Updated vlc to actual version

[ipfire-2.x.git] / src / patches / reiser4-for-2.6.20.patch

diff -urN linux-2.6.20.orig/arch/i386/lib/usercopy.c linux-2.6.20/arch/i386/lib/usercopy.c
--- linux-2.6.20.orig/arch/i386/lib/usercopy.c  2006-11-30 00:57:37.000000000 +0300
+++ linux-2.6.20/arch/i386/lib/usercopy.c       2007-05-06 14:50:43.658963226 +0400
@@ -812,6 +812,7 @@
 #endif
        return n;
 }
+EXPORT_SYMBOL(__copy_from_user_ll_nocache);
 
 unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
                                        unsigned long n)
@@ -827,6 +828,7 @@
 #endif
        return n;
 }
+EXPORT_SYMBOL(__copy_from_user_ll_nocache_nozero);
 
 /**
  * copy_to_user: - Copy a block of data into user space.
diff -urN linux-2.6.20.orig/Documentation/Changes linux-2.6.20/Documentation/Changes
--- linux-2.6.20.orig/Documentation/Changes     2007-05-06 15:04:34.226399593 +0400
+++ linux-2.6.20/Documentation/Changes  2007-05-06 14:50:43.658963226 +0400
@@ -36,6 +36,7 @@
 o  e2fsprogs              1.29                    # tune2fs
 o  jfsutils               1.1.3                   # fsck.jfs -V
 o  reiserfsprogs          3.6.3                   # reiserfsck -V 2>&1|grep reiserfsprogs
+o  reiser4progs           1.0.0                   # fsck.reiser4 -V
 o  xfsprogs               2.6.0                   # xfs_db -V
 o  pcmciautils            004                     # pccardctl -V
 o  quota-tools            3.09                    # quota -V
@@ -144,6 +145,13 @@
 versions of mkreiserfs, resize_reiserfs, debugreiserfs and
 reiserfsck. These utils work on both i386 and alpha platforms.
 
+Reiser4progs
+------------
+
+The reiser4progs package contains utilities for the reiser4 file system.
+Detailed instructions are provided in the README file located at:
+<ftp://ftp.namesys.com/pub/reiser4progs/README>.
+
 Xfsprogs
 --------
 
@@ -322,6 +330,10 @@
 -------------
 o  <http://www.namesys.com/pub/reiserfsprogs/reiserfsprogs-3.6.3.tar.gz>
 
+Reiser4progs
+------------
+o  <ftp://ftp.namesys.com/pub/reiser4progs/>
+
 Xfsprogs
 --------
 o  <ftp://oss.sgi.com/projects/xfs/download/>
diff -urN linux-2.6.20.orig/Documentation/filesystems/reiser4.txt linux-2.6.20/Documentation/filesystems/reiser4.txt
--- linux-2.6.20.orig/Documentation/filesystems/reiser4.txt     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/Documentation/filesystems/reiser4.txt  2007-05-06 14:50:43.658963226 +0400
@@ -0,0 +1,75 @@
+Reiser4 filesystem
+==================
+Reiser4 is a file system based on dancing tree algorithms, and is
+described at http://www.namesys.com
+
+
+References
+==========
+web page               http://namesys.com/v4/v4.html
+source code            ftp://ftp.namesys.com/pub/reiser4-for-2.6/
+userland tools         ftp://ftp.namesys.com/pub/reiser4progs/
+install page           http://www.namesys.com/install_v4.html
+
+Compile options
+===============
+Enable reiser4 debug mode
+       This checks everything imaginable while reiser4
+       runs
+
+Mount options
+=============
+tmgr.atom_max_size=N
+       Atoms containing more than N blocks will be forced to commit.
+       N is decimal.
+       Default is nr_free_pagecache_pages() / 2 at mount time.
+
+tmgr.atom_max_age=N
+       Atoms older than N seconds will be forced to commit. N is decimal.
+       Default is 600.
+
+tmgr.atom_max_flushers=N
+       Limit of concurrent flushers for one atom. 0 means no limit.
+       Default is 0.
+
+tree.cbk_cache.nr_slots=N
+       Number of slots in the cbk cache.
+
+flush.relocate_threshold=N
+       If flush finds more than N adjacent dirty leaf-level blocks it
+       will force them to be relocated.
+       Default is 64.
+
+flush.relocate_distance=N
+       If flush finds can find a block allocation closer than at most
+       N from the preceder it will relocate to that position.
+       Default is 64.
+
+flush.scan_maxnodes=N
+       The maximum number of nodes to scan left on a level during
+       flush.
+       Default is 10000.
+
+optimal_io_size=N
+       Preferred IO size. This value is used to set st_blksize of
+       struct stat.
+       Default is 65536.
+
+bsdgroups
+       Turn on BSD-style gid assignment.
+
+32bittimes
+       By default file in reiser4 have 64 bit timestamps. Files
+       created when filesystem is mounted with 32bittimes mount
+       option will get 32 bit timestamps.
+
+mtflush
+       Turn off concurrent flushing.
+
+nopseudo
+       Disable pseudo files support. See
+       http://namesys.com/v4/pseudo.html for more about pseudo files.
+
+dont_load_bitmap
+       Don't load all bitmap blocks at mount time, it is useful for
+       machines with tiny RAM and large disks.
diff -urN linux-2.6.20.orig/fs/fs-writeback.c linux-2.6.20/fs/fs-writeback.c
--- linux-2.6.20.orig/fs/fs-writeback.c 2007-05-06 15:04:39.848155607 +0400
+++ linux-2.6.20/fs/fs-writeback.c      2007-05-06 14:50:43.662964476 +0400
@@ -296,8 +296,6 @@
  * WB_SYNC_HOLD is a hack for sys_sync(): reattach the inode to sb->s_dirty so
  * that it can be located for waiting on in __writeback_single_inode().
  *
- * Called under inode_lock.
- *
  * If `bdi' is non-zero then we're being asked to writeback a specific queue.
  * This function assumes that the blockdev superblock's inodes are backed by
  * a variety of queues, so all inodes are searched.  For other superblocks,
@@ -313,11 +311,13 @@
  * on the writer throttling path, and we get decent balancing between many
  * throttled threads: we don't want them all piling up on __wait_on_inode.
  */
-static void
-sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
+void
+generic_sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
 {
        const unsigned long start = jiffies;    /* livelock avoidance */
 
+       spin_lock(&inode_lock);
+
        if (!wbc->for_kupdate || list_empty(&sb->s_io))
                list_splice_init(&sb->s_dirty, &sb->s_io);
 
@@ -397,8 +397,19 @@
                if (wbc->nr_to_write <= 0)
                        break;
        }
+       spin_unlock(&inode_lock);
        return;         /* Leave any unwritten inodes on s_io */
 }
+EXPORT_SYMBOL(generic_sync_sb_inodes);
+
+static void
+sync_sb_inodes(struct super_block *sb, struct writeback_control *wbc)
+{
+       if (sb->s_op->sync_inodes)
+               sb->s_op->sync_inodes(sb, wbc);
+       else
+               generic_sync_sb_inodes(sb, wbc);
+}
 
 /*
  * Start writeback of dirty pagecache data against all unlocked inodes.
@@ -439,11 +450,8 @@
                         * be unmounted by the time it is released.
                         */
                        if (down_read_trylock(&sb->s_umount)) {
-                               if (sb->s_root) {
-                                       spin_lock(&inode_lock);
+                               if (sb->s_root)
                                        sync_sb_inodes(sb, wbc);
-                                       spin_unlock(&inode_lock);
-                               }
                                up_read(&sb->s_umount);
                        }
                        spin_lock(&sb_lock);
@@ -481,9 +489,7 @@
                        (inodes_stat.nr_inodes - inodes_stat.nr_unused) +
                        nr_dirty + nr_unstable;
        wbc.nr_to_write += wbc.nr_to_write / 2;         /* Bit more for luck */
-       spin_lock(&inode_lock);
        sync_sb_inodes(sb, &wbc);
-       spin_unlock(&inode_lock);
 }
 
 /*
diff -urN linux-2.6.20.orig/fs/Kconfig linux-2.6.20/fs/Kconfig
--- linux-2.6.20.orig/fs/Kconfig        2007-05-06 15:04:39.668099364 +0400
+++ linux-2.6.20/fs/Kconfig     2007-05-06 14:50:43.662964476 +0400
@@ -272,6 +272,8 @@
        default y if EXT2_FS=y || EXT3_FS=y || EXT4DEV_FS=y
        default m if EXT2_FS=m || EXT3_FS=m || EXT4DEV_FS=m
 
+source "fs/reiser4/Kconfig"
+
 config REISERFS_FS
        tristate "Reiserfs support"
        help
diff -urN linux-2.6.20.orig/fs/Makefile linux-2.6.20/fs/Makefile
--- linux-2.6.20.orig/fs/Makefile       2007-05-06 15:04:39.668099364 +0400
+++ linux-2.6.20/fs/Makefile    2007-05-06 14:50:43.666965726 +0400
@@ -62,6 +62,7 @@
  
 # Do not add any filesystems before this line
 obj-$(CONFIG_REISERFS_FS)      += reiserfs/
+obj-$(CONFIG_REISER4_FS)       += reiser4/
 obj-$(CONFIG_EXT3_FS)          += ext3/ # Before ext2 so root fs can be ext3
 obj-$(CONFIG_EXT4DEV_FS)       += ext4/ # Before ext2 so root fs can be ext4dev
 obj-$(CONFIG_JBD)              += jbd/
diff -urN linux-2.6.20.orig/fs/reiser4/as_ops.c linux-2.6.20/fs/reiser4/as_ops.c
--- linux-2.6.20.orig/fs/reiser4/as_ops.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/as_ops.c    2007-05-06 14:50:43.666965726 +0400
@@ -0,0 +1,337 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Interface to VFS. Reiser4 address_space_operations are defined here. */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/file/file.h"
+#include "plugin/security/perm.h"
+#include "plugin/disk_format/disk_format.h"
+#include "plugin/plugin.h"
+#include "plugin/plugin_set.h"
+#include "plugin/object.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "page_cache.h"
+#include "ktxnmgrd.h"
+#include "super.h"
+#include "reiser4.h"
+#include "entd.h"
+
+#include <linux/profile.h>
+#include <linux/types.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/mm.h>
+#include <linux/buffer_head.h>
+#include <linux/dcache.h>
+#include <linux/list.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/quotaops.h>
+#include <linux/security.h>
+
+/* address space operations */
+
+/**
+ * reiser4_set_page_dirty - set dirty bit, tag in page tree, dirty accounting
+ * @page: page to be dirtied
+ *
+ * Operation of struct address_space_operations. This implementation is used by
+ * unix and cryptcompress file plugins.
+ *
+ * This is called when reiser4 page gets dirtied outside of reiser4, for
+ * example, when dirty bit is moved from pte to physical page.
+ *
+ * Tags page in the mapping's page tree with special tag so that it is possible
+ * to do all the reiser4 specific work wrt dirty pages (jnode creation,
+ * capturing by an atom) later because it can not be done in the contexts where
+ * set_page_dirty is called.
+ */
+int reiser4_set_page_dirty(struct page *page)
+{
+       /* this page can be unformatted only */
+       assert("vs-1734", (page->mapping &&
+                          page->mapping->host &&
+                          reiser4_get_super_fake(page->mapping->host->i_sb) !=
+                          page->mapping->host
+                          && reiser4_get_cc_fake(page->mapping->host->i_sb) !=
+                          page->mapping->host
+                          && reiser4_get_bitmap_fake(page->mapping->host->i_sb) !=
+                          page->mapping->host));
+
+       if (!TestSetPageDirty(page)) {
+               struct address_space *mapping = page->mapping;
+
+               if (mapping) {
+                       write_lock_irq(&mapping->tree_lock);
+
+                       /* check for race with truncate */
+                       if (page->mapping) {
+                               assert("vs-1652", page->mapping == mapping);
+                               if (mapping_cap_account_dirty(mapping))
+                                       inc_zone_page_state(page,
+                                                       NR_FILE_DIRTY);
+                               radix_tree_tag_set(&mapping->page_tree,
+                                                  page->index,
+                                                  PAGECACHE_TAG_REISER4_MOVED);
+                       }
+                       write_unlock_irq(&mapping->tree_lock);
+                       __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+               }
+       }
+       return 0;
+}
+
+/* ->invalidatepage method for reiser4 */
+
+/*
+ * this is called for each truncated page from
+ * truncate_inode_pages()->truncate_{complete,partial}_page().
+ *
+ * At the moment of call, page is under lock, and outstanding io (if any) has
+ * completed.
+ */
+
+/**
+ * reiser4_invalidatepage
+ * @page: page to invalidate
+ * @offset: starting offset for partial invalidation
+ *
+ */
+void reiser4_invalidatepage(struct page *page, unsigned long offset)
+{
+       int ret = 0;
+       reiser4_context *ctx;
+       struct inode *inode;
+       jnode *node;
+
+       /*
+        * This is called to truncate file's page.
+        *
+        * Originally, reiser4 implemented truncate in a standard way
+        * (vmtruncate() calls ->invalidatepage() on all truncated pages
+        * first, then file system ->truncate() call-back is invoked).
+        *
+        * This lead to the problem when ->invalidatepage() was called on a
+        * page with jnode that was captured into atom in ASTAGE_PRE_COMMIT
+        * process. That is, truncate was bypassing transactions. To avoid
+        * this, try_capture_page_to_invalidate() call was added here.
+        *
+        * After many troubles with vmtruncate() based truncate (including
+        * races with flush, tail conversion, etc.) it was re-written in the
+        * top-to-bottom style: items are killed in reiser4_cut_tree_object()
+        * and pages belonging to extent are invalidated in kill_hook_extent().
+        * So probably now additional call to capture is not needed here.
+        */
+
+       assert("nikita-3137", PageLocked(page));
+       assert("nikita-3138", !PageWriteback(page));
+       inode = page->mapping->host;
+
+       /*
+        * ->invalidatepage() should only be called for the unformatted
+        * jnodes. Destruction of all other types of jnodes is performed
+        * separately. But, during some corner cases (like handling errors
+        * during mount) it is simpler to let ->invalidatepage to be called on
+        * them. Check for this, and do nothing.
+        */
+       if (reiser4_get_super_fake(inode->i_sb) == inode)
+               return;
+       if (reiser4_get_cc_fake(inode->i_sb) == inode)
+               return;
+       if (reiser4_get_bitmap_fake(inode->i_sb) == inode)
+               return;
+       assert("vs-1426", PagePrivate(page));
+       assert("vs-1427",
+              page->mapping == jnode_get_mapping(jnode_by_page(page)));
+       assert("", jprivate(page) != NULL);
+       assert("", ergo(inode_file_plugin(inode) !=
+                       file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID),
+                       offset == 0));
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return;
+
+       node = jprivate(page);
+       spin_lock_jnode(node);
+       if (!(node->state & ((1 << JNODE_DIRTY) | (1<< JNODE_FLUSH_QUEUED) |
+                         (1 << JNODE_WRITEBACK) | (1 << JNODE_OVRWR)))) {
+               /* there is not need to capture */
+               jref(node);
+               JF_SET(node, JNODE_HEARD_BANSHEE);
+               page_clear_jnode(page, node);
+               reiser4_uncapture_jnode(node);
+               unhash_unformatted_jnode(node);
+               jput(node);
+               reiser4_exit_context(ctx);
+               return;
+       }
+       spin_unlock_jnode(node);
+
+       /* capture page being truncated. */
+       ret = try_capture_page_to_invalidate(page);
+       if (ret != 0)
+               warning("nikita-3141", "Cannot capture: %i", ret);
+
+       if (offset == 0) {
+               /* remove jnode from transaction and detach it from page. */
+               jref(node);
+               JF_SET(node, JNODE_HEARD_BANSHEE);
+               /* page cannot be detached from jnode concurrently, because it
+                * is locked */
+               reiser4_uncapture_page(page);
+
+               /* this detaches page from jnode, so that jdelete will not try
+                * to lock page which is already locked */
+               spin_lock_jnode(node);
+               page_clear_jnode(page, node);
+               spin_unlock_jnode(node);
+               unhash_unformatted_jnode(node);
+
+               jput(node);
+       }
+
+       reiser4_exit_context(ctx);
+}
+
+/* help function called from reiser4_releasepage(). It returns true if jnode
+ * can be detached from its page and page released. */
+int jnode_is_releasable(jnode * node /* node to check */ )
+{
+       assert("nikita-2781", node != NULL);
+       assert_spin_locked(&(node->guard));
+       assert_spin_locked(&(node->load));
+
+       /* is some thread is currently using jnode page, later cannot be
+        * detached */
+       if (atomic_read(&node->d_count) != 0) {
+               return 0;
+       }
+
+       assert("vs-1214", !jnode_is_loaded(node));
+
+       /*
+        * can only release page if real block number is assigned to it. Simple
+        * check for ->atom wouldn't do, because it is possible for node to be
+        * clean, not it atom yet, and still having fake block number. For
+        * example, node just created in jinit_new().
+        */
+       if (reiser4_blocknr_is_fake(jnode_get_block(node)))
+               return 0;
+
+       /*
+        * pages prepared for write can not be released anyway, so avoid
+        * detaching jnode from the page
+        */
+       if (JF_ISSET(node, JNODE_WRITE_PREPARED))
+               return 0;
+
+       /*
+        * dirty jnode cannot be released. It can however be submitted to disk
+        * as part of early flushing, but only after getting flush-prepped.
+        */
+       if (JF_ISSET(node, JNODE_DIRTY))
+               return 0;
+
+       /* overwrite set is only written by log writer. */
+       if (JF_ISSET(node, JNODE_OVRWR))
+               return 0;
+
+       /* jnode is already under writeback */
+       if (JF_ISSET(node, JNODE_WRITEBACK))
+               return 0;
+
+       /* don't flush bitmaps or journal records */
+       if (!jnode_is_znode(node) && !jnode_is_unformatted(node))
+               return 0;
+
+       return 1;
+}
+
+/*
+ * ->releasepage method for reiser4
+ *
+ * This is called by VM scanner when it comes across clean page.  What we have
+ * to do here is to check whether page can really be released (freed that is)
+ * and if so, detach jnode from it and remove page from the page cache.
+ *
+ * Check for releasability is done by releasable() function.
+ */
+int reiser4_releasepage(struct page *page, gfp_t gfp UNUSED_ARG)
+{
+       jnode *node;
+
+       assert("nikita-2257", PagePrivate(page));
+       assert("nikita-2259", PageLocked(page));
+       assert("nikita-2892", !PageWriteback(page));
+       assert("nikita-3019", reiser4_schedulable());
+
+       /* NOTE-NIKITA: this can be called in the context of reiser4 call. It
+          is not clear what to do in this case. A lot of deadlocks seems be
+          possible. */
+
+       node = jnode_by_page(page);
+       assert("nikita-2258", node != NULL);
+       assert("reiser4-4", page->mapping != NULL);
+       assert("reiser4-5", page->mapping->host != NULL);
+
+       if (PageDirty(page))
+               return 0;
+
+       /* extra page reference is used by reiser4 to protect
+        * jnode<->page link from this ->releasepage(). */
+       if (page_count(page) > 3)
+               return 0;
+
+       /* releasable() needs jnode lock, because it looks at the jnode fields
+        * and we need jload_lock here to avoid races with jload(). */
+       spin_lock_jnode(node);
+       spin_lock(&(node->load));
+       if (jnode_is_releasable(node)) {
+               struct address_space *mapping;
+
+               mapping = page->mapping;
+               jref(node);
+               /* there is no need to synchronize against
+                * jnode_extent_write() here, because pages seen by
+                * jnode_extent_write() are !releasable(). */
+               page_clear_jnode(page, node);
+               spin_unlock(&(node->load));
+               spin_unlock_jnode(node);
+
+               /* we are under memory pressure so release jnode also. */
+               jput(node);
+
+               return 1;
+       } else {
+               spin_unlock(&(node->load));
+               spin_unlock_jnode(node);
+               assert("nikita-3020", reiser4_schedulable());
+               return 0;
+       }
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/block_alloc.c linux-2.6.20/fs/reiser4/block_alloc.c
--- linux-2.6.20.orig/fs/reiser4/block_alloc.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/block_alloc.c       2007-05-06 14:50:43.682970725 +0400
@@ -0,0 +1,1137 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "debug.h"
+#include "dformat.h"
+#include "plugin/plugin.h"
+#include "txnmgr.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "super.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/spinlock.h>
+
+/* THE REISER4 DISK SPACE RESERVATION SCHEME. */
+
+/* We need to be able to reserve enough disk space to ensure that an atomic
+   operation will have enough disk space to flush (see flush.c and
+   http://namesys.com/v4/v4.html) and commit it once it is started.
+
+   In our design a call for reserving disk space may fail but not an actual
+   block allocation.
+
+   All free blocks, already allocated blocks, and all kinds of reserved blocks
+   are counted in different per-fs block counters.
+
+   A reiser4 super block's set of block counters currently is:
+
+   free -- free blocks,
+   used -- already allocated blocks,
+
+   grabbed -- initially reserved for performing an fs operation, those blocks
+          are taken from free blocks, then grabbed disk space leaks from grabbed
+          blocks counter to other counters like "fake allocated", "flush
+          reserved", "used", the rest of not used grabbed space is returned to
+          free space at the end of fs operation;
+
+   fake allocated -- counts all nodes without real disk block numbers assigned,
+                     we have separate accounting for formatted and unformatted
+                     nodes (for easier debugging);
+
+   flush reserved -- disk space needed for flushing and committing an atom.
+                     Each dirty already allocated block could be written as a
+                     part of atom's overwrite set or as a part of atom's
+                     relocate set.  In both case one additional block is needed,
+                     it is used as a wandered block if we do overwrite or as a
+                    new location for a relocated block.
+
+   In addition, blocks in some states are counted on per-thread and per-atom
+   basis.  A reiser4 context has a counter of blocks grabbed by this transaction
+   and the sb's grabbed blocks counter is a sum of grabbed blocks counter values
+   of each reiser4 context.  Each reiser4 atom has a counter of "flush reserved"
+   blocks, which are reserved for flush processing and atom commit. */
+
+/* AN EXAMPLE: suppose we insert new item to the reiser4 tree.  We estimate
+   number of blocks to grab for most expensive case of balancing when the leaf
+   node we insert new item to gets split and new leaf node is allocated.
+
+   So, we need to grab blocks for
+
+   1) one block for possible dirtying the node we insert an item to. That block
+      would be used for node relocation at flush time or for allocating of a
+      wandered one, it depends what will be a result (what set, relocate or
+      overwrite the node gets assigned to) of the node processing by the flush
+      algorithm.
+
+   2) one block for either allocating a new node, or dirtying of right or left
+      clean neighbor, only one case may happen.
+
+   VS-FIXME-HANS: why can only one case happen? I would expect to see dirtying of left neighbor, right neighbor, current
+   node, and creation of new node.  have I forgotten something?  email me.
+
+   These grabbed blocks are counted in both reiser4 context "grabbed blocks"
+   counter and in the fs-wide one (both ctx->grabbed_blocks and
+   sbinfo->blocks_grabbed get incremented by 2), sb's free blocks counter is
+   decremented by 2.
+
+   Suppose both two blocks were spent for dirtying of an already allocated clean
+   node (one block went from "grabbed" to "flush reserved") and for new block
+   allocating (one block went from "grabbed" to "fake allocated formatted").
+
+   Inserting of a child pointer to the parent node caused parent node to be
+   split, the balancing code takes care about this grabbing necessary space
+   immediately by calling reiser4_grab with BA_RESERVED flag set which means
+   "can use the 5% reserved disk space".
+
+   At this moment insertion completes and grabbed blocks (if they were not used)
+   should be returned to the free space counter.
+
+   However the atom life-cycle is not completed.  The atom had one "flush
+   reserved" block added by our insertion and the new fake allocated node is
+   counted as a "fake allocated formatted" one.  The atom has to be fully
+   processed by flush before commit.  Suppose that the flush moved the first,
+   already allocated node to the atom's overwrite list, the new fake allocated
+   node, obviously, went into the atom relocate set.  The reiser4 flush
+   allocates the new node using one unit from "fake allocated formatted"
+   counter, the log writer uses one from "flush reserved" for wandered block
+   allocation.
+
+   And, it is not the end.  When the wandered block is deallocated after the
+   atom gets fully played (see wander.c for term description), the disk space
+   occupied for it is returned to free blocks. */
+
+/* BLOCK NUMBERS */
+
+/* Any reiser4 node has a block number assigned to it.  We use these numbers for
+   indexing in hash tables, so if a block has not yet been assigned a location
+   on disk we need to give it a temporary fake block number.
+
+   Current implementation of reiser4 uses 64-bit integers for block numbers. We
+   use highest bit in 64-bit block number to distinguish fake and real block
+   numbers. So, only 63 bits may be used to addressing of real device
+   blocks. That "fake" block numbers space is divided into subspaces of fake
+   block numbers for data blocks and for shadow (working) bitmap blocks.
+
+   Fake block numbers for data blocks are generated by a cyclic counter, which
+   gets incremented after each real block allocation. We assume that it is
+   impossible to overload this counter during one transaction life. */
+
+/* Initialize a blocknr hint. */
+void reiser4_blocknr_hint_init(reiser4_blocknr_hint * hint)
+{
+       memset(hint, 0, sizeof(reiser4_blocknr_hint));
+}
+
+/* Release any resources of a blocknr hint. */
+void reiser4_blocknr_hint_done(reiser4_blocknr_hint * hint UNUSED_ARG)
+{
+       /* No resources should be freed in current blocknr_hint implementation. */
+}
+
+/* see above for explanation of fake block number.  */
+/* Audited by: green(2002.06.11) */
+int reiser4_blocknr_is_fake(const reiser4_block_nr * da)
+{
+       /* The reason for not simply returning result of '&' operation is that
+          while return value is (possibly 32bit) int,  the reiser4_block_nr is
+          at least 64 bits long, and high bit (which is the only possible
+          non zero bit after the masking) would be stripped off */
+       return (*da & REISER4_FAKE_BLOCKNR_BIT_MASK) ? 1 : 0;
+}
+
+/* Static functions for <reiser4 super block>/<reiser4 context> block counters
+   arithmetic. Mostly, they are isolated to not to code same assertions in
+   several places. */
+static void sub_from_ctx_grabbed(reiser4_context * ctx, __u64 count)
+{
+       BUG_ON(ctx->grabbed_blocks < count);
+       assert("zam-527", ctx->grabbed_blocks >= count);
+       ctx->grabbed_blocks -= count;
+}
+
+static void add_to_ctx_grabbed(reiser4_context * ctx, __u64 count)
+{
+       ctx->grabbed_blocks += count;
+}
+
+static void sub_from_sb_grabbed(reiser4_super_info_data * sbinfo, __u64 count)
+{
+       assert("zam-525", sbinfo->blocks_grabbed >= count);
+       sbinfo->blocks_grabbed -= count;
+}
+
+/* Decrease the counter of block reserved for flush in super block. */
+static void
+sub_from_sb_flush_reserved(reiser4_super_info_data * sbinfo, __u64 count)
+{
+       assert("vpf-291", sbinfo->blocks_flush_reserved >= count);
+       sbinfo->blocks_flush_reserved -= count;
+}
+
+static void
+sub_from_sb_fake_allocated(reiser4_super_info_data * sbinfo, __u64 count,
+                          reiser4_ba_flags_t flags)
+{
+       if (flags & BA_FORMATTED) {
+               assert("zam-806", sbinfo->blocks_fake_allocated >= count);
+               sbinfo->blocks_fake_allocated -= count;
+       } else {
+               assert("zam-528",
+                      sbinfo->blocks_fake_allocated_unformatted >= count);
+               sbinfo->blocks_fake_allocated_unformatted -= count;
+       }
+}
+
+static void sub_from_sb_used(reiser4_super_info_data * sbinfo, __u64 count)
+{
+       assert("zam-530",
+              sbinfo->blocks_used >= count + sbinfo->min_blocks_used);
+       sbinfo->blocks_used -= count;
+}
+
+static void
+sub_from_cluster_reserved(reiser4_super_info_data * sbinfo, __u64 count)
+{
+       assert("edward-501", sbinfo->blocks_clustered >= count);
+       sbinfo->blocks_clustered -= count;
+}
+
+/* Increase the counter of block reserved for flush in atom. */
+static void add_to_atom_flush_reserved_nolock(txn_atom * atom, __u32 count)
+{
+       assert("zam-772", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+       atom->flush_reserved += count;
+}
+
+/* Decrease the counter of block reserved for flush in atom. */
+static void sub_from_atom_flush_reserved_nolock(txn_atom * atom, __u32 count)
+{
+       assert("zam-774", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+       assert("nikita-2790", atom->flush_reserved >= count);
+       atom->flush_reserved -= count;
+}
+
+/* super block has 6 counters: free, used, grabbed, fake allocated
+   (formatted and unformatted) and flush reserved. Their sum must be
+   number of blocks on a device. This function checks this */
+int reiser4_check_block_counters(const struct super_block *super)
+{
+       __u64 sum;
+
+       sum = reiser4_grabbed_blocks(super) + reiser4_free_blocks(super) +
+           reiser4_data_blocks(super) + reiser4_fake_allocated(super) +
+           reiser4_fake_allocated_unformatted(super) + reiser4_flush_reserved(super) +
+           reiser4_clustered_blocks(super);
+       if (reiser4_block_count(super) != sum) {
+               printk("super block counters: "
+                      "used %llu, free %llu, "
+                      "grabbed %llu, fake allocated (formatetd %llu, unformatted %llu), "
+                      "reserved %llu, clustered %llu, sum %llu, must be (block count) %llu\n",
+                      (unsigned long long)reiser4_data_blocks(super),
+                      (unsigned long long)reiser4_free_blocks(super),
+                      (unsigned long long)reiser4_grabbed_blocks(super),
+                      (unsigned long long)reiser4_fake_allocated(super),
+                      (unsigned long long)
+                      reiser4_fake_allocated_unformatted(super),
+                      (unsigned long long)reiser4_flush_reserved(super),
+                      (unsigned long long)reiser4_clustered_blocks(super),
+                      (unsigned long long)sum,
+                      (unsigned long long)reiser4_block_count(super));
+               return 0;
+       }
+       return 1;
+}
+
+/* Adjust "working" free blocks counter for number of blocks we are going to
+   allocate.  Record number of grabbed blocks in fs-wide and per-thread
+   counters.  This function should be called before bitmap scanning or
+   allocating fake block numbers
+
+   @super           -- pointer to reiser4 super block;
+   @count           -- number of blocks we reserve;
+
+   @return          -- 0 if success,  -ENOSPC, if all
+                       free blocks are preserved or already allocated.
+*/
+
+static int
+reiser4_grab(reiser4_context * ctx, __u64 count, reiser4_ba_flags_t flags)
+{
+       __u64 free_blocks;
+       int ret = 0, use_reserved = flags & BA_RESERVED;
+       reiser4_super_info_data *sbinfo;
+
+       assert("vs-1276", ctx == get_current_context());
+
+       /* Do not grab anything on ro-mounted fs. */
+       if (rofs_super(ctx->super)) {
+               ctx->grab_enabled = 0;
+               return 0;
+       }
+
+       sbinfo = get_super_private(ctx->super);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       free_blocks = sbinfo->blocks_free;
+
+       if ((use_reserved && free_blocks < count) ||
+           (!use_reserved && free_blocks < count + sbinfo->blocks_reserved)) {
+               ret = RETERR(-ENOSPC);
+               goto unlock_and_ret;
+       }
+
+       add_to_ctx_grabbed(ctx, count);
+
+       sbinfo->blocks_grabbed += count;
+       sbinfo->blocks_free -= count;
+
+#if REISER4_DEBUG
+       if (ctx->grabbed_initially == 0)
+               ctx->grabbed_initially = count;
+#endif
+
+       assert("nikita-2986", reiser4_check_block_counters(ctx->super));
+
+       /* disable grab space in current context */
+       ctx->grab_enabled = 0;
+
+      unlock_and_ret:
+       spin_unlock_reiser4_super(sbinfo);
+
+       return ret;
+}
+
+int reiser4_grab_space(__u64 count, reiser4_ba_flags_t flags)
+{
+       int ret;
+       reiser4_context *ctx;
+
+       assert("nikita-2964", ergo(flags & BA_CAN_COMMIT,
+                                  lock_stack_isclean(get_current_lock_stack
+                                                     ())));
+       ctx = get_current_context();
+       if (!(flags & BA_FORCE) && !is_grab_enabled(ctx)) {
+               return 0;
+       }
+
+       ret = reiser4_grab(ctx, count, flags);
+       if (ret == -ENOSPC) {
+
+               /* Trying to commit the all transactions if BA_CAN_COMMIT flag present */
+               if (flags & BA_CAN_COMMIT) {
+                       txnmgr_force_commit_all(ctx->super, 0);
+                       ctx->grab_enabled = 1;
+                       ret = reiser4_grab(ctx, count, flags);
+               }
+       }
+       /*
+        * allocation from reserved pool cannot fail. This is severe error.
+        */
+       assert("nikita-3005", ergo(flags & BA_RESERVED, ret == 0));
+       return ret;
+}
+
+/*
+ * SPACE RESERVED FOR UNLINK/TRUNCATE
+ *
+ * Unlink and truncate require space in transaction (to update stat data, at
+ * least). But we don't want rm(1) to fail with "No space on device" error.
+ *
+ * Solution is to reserve 5% of disk space for truncates and
+ * unlinks. Specifically, normal space grabbing requests don't grab space from
+ * reserved area. Only requests with BA_RESERVED bit in flags are allowed to
+ * drain it. Per super block delete mutex is used to allow only one
+ * thread at a time to grab from reserved area.
+ *
+ * Grabbing from reserved area should always be performed with BA_CAN_COMMIT
+ * flag.
+ *
+ */
+
+int reiser4_grab_reserved(struct super_block *super,
+                         __u64 count, reiser4_ba_flags_t flags)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(super);
+
+       assert("nikita-3175", flags & BA_CAN_COMMIT);
+
+       /* Check the delete mutex already taken by us, we assume that
+        * reading of machine word is atomic. */
+       if (sbinfo->delete_mutex_owner == current) {
+               if (reiser4_grab_space
+                   (count, (flags | BA_RESERVED) & ~BA_CAN_COMMIT)) {
+                       warning("zam-1003",
+                               "nested call of grab_reserved fails count=(%llu)",
+                               (unsigned long long)count);
+                       reiser4_release_reserved(super);
+                       return RETERR(-ENOSPC);
+               }
+               return 0;
+       }
+
+       if (reiser4_grab_space(count, flags)) {
+               mutex_lock(&sbinfo->delete_mutex);
+               assert("nikita-2929", sbinfo->delete_mutex_owner == NULL);
+               sbinfo->delete_mutex_owner = current;
+
+               if (reiser4_grab_space(count, flags | BA_RESERVED)) {
+                       warning("zam-833",
+                               "reserved space is not enough (%llu)",
+                               (unsigned long long)count);
+                       reiser4_release_reserved(super);
+                       return RETERR(-ENOSPC);
+               }
+       }
+       return 0;
+}
+
+void reiser4_release_reserved(struct super_block *super)
+{
+       reiser4_super_info_data *info;
+
+       info = get_super_private(super);
+       if (info->delete_mutex_owner == current) {
+               info->delete_mutex_owner = NULL;
+               mutex_unlock(&info->delete_mutex);
+       }
+}
+
+static reiser4_super_info_data *grabbed2fake_allocated_head(int count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sub_from_ctx_grabbed(ctx, count);
+
+       sbinfo = get_super_private(ctx->super);
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_grabbed(sbinfo, count);
+       /* return sbinfo locked */
+       return sbinfo;
+}
+
+/* is called after @count fake block numbers are allocated and pointer to
+   those blocks are inserted into tree. */
+static void grabbed2fake_allocated_formatted(void)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = grabbed2fake_allocated_head(1);
+       sbinfo->blocks_fake_allocated++;
+
+       assert("vs-922", reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/**
+ * grabbed2fake_allocated_unformatted
+ * @count:
+ *
+ */
+static void grabbed2fake_allocated_unformatted(int count)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = grabbed2fake_allocated_head(count);
+       sbinfo->blocks_fake_allocated_unformatted += count;
+
+       assert("vs-9221", reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+void grabbed2cluster_reserved(int count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sub_from_ctx_grabbed(ctx, count);
+
+       sbinfo = get_super_private(ctx->super);
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_grabbed(sbinfo, count);
+       sbinfo->blocks_clustered += count;
+
+       assert("edward-504", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+void cluster_reserved2grabbed(int count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+
+       sbinfo = get_super_private(ctx->super);
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_cluster_reserved(sbinfo, count);
+       sbinfo->blocks_grabbed += count;
+
+       assert("edward-505", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+       add_to_ctx_grabbed(ctx, count);
+}
+
+void cluster_reserved2free(int count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       cluster_reserved2grabbed(count);
+       grabbed2free(ctx, sbinfo, count);
+}
+
+static DEFINE_SPINLOCK(fake_lock);
+static reiser4_block_nr fake_gen = 0;
+
+/**
+ * assign_fake_blocknr
+ * @blocknr:
+ * @count:
+ *
+ * Obtain a fake block number for new node which will be used to refer to
+ * this newly allocated node until real allocation is done.
+ */
+static void assign_fake_blocknr(reiser4_block_nr *blocknr, int count)
+{
+       spin_lock(&fake_lock);
+       *blocknr = fake_gen;
+       fake_gen += count;
+       spin_unlock(&fake_lock);
+
+       BUG_ON(*blocknr & REISER4_BLOCKNR_STATUS_BIT_MASK);
+       /**blocknr &= ~REISER4_BLOCKNR_STATUS_BIT_MASK;*/
+       *blocknr |= REISER4_UNALLOCATED_STATUS_VALUE;
+       assert("zam-394", zlook(current_tree, blocknr) == NULL);
+}
+
+int assign_fake_blocknr_formatted(reiser4_block_nr * blocknr)
+{
+       assign_fake_blocknr(blocknr, 1);
+       grabbed2fake_allocated_formatted();
+       return 0;
+}
+
+/**
+ * fake_blocknrs_unformatted
+ * @count: number of fake numbers to get
+ *
+ * Allocates @count fake block numbers which will be assigned to jnodes
+ */
+reiser4_block_nr fake_blocknr_unformatted(int count)
+{
+       reiser4_block_nr blocknr;
+
+       assign_fake_blocknr(&blocknr, count);
+       grabbed2fake_allocated_unformatted(count);
+
+       return blocknr;
+}
+
+/* adjust sb block counters, if real (on-disk) block allocation immediately
+   follows grabbing of free disk space. */
+static void grabbed2used(reiser4_context *ctx, reiser4_super_info_data *sbinfo,
+                        __u64 count)
+{
+       sub_from_ctx_grabbed(ctx, count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_grabbed(sbinfo, count);
+       sbinfo->blocks_used += count;
+
+       assert("nikita-2679", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* adjust sb block counters when @count unallocated blocks get mapped to disk */
+static void fake_allocated2used(reiser4_super_info_data *sbinfo, __u64 count,
+                               reiser4_ba_flags_t flags)
+{
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_fake_allocated(sbinfo, count, flags);
+       sbinfo->blocks_used += count;
+
+       assert("nikita-2680",
+              reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+static void flush_reserved2used(txn_atom * atom, __u64 count)
+{
+       reiser4_super_info_data *sbinfo;
+
+       assert("zam-787", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       sub_from_atom_flush_reserved_nolock(atom, (__u32) count);
+
+       sbinfo = get_current_super_private();
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_flush_reserved(sbinfo, count);
+       sbinfo->blocks_used += count;
+
+       assert("zam-789",
+              reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* update the per fs  blocknr hint default value. */
+void
+update_blocknr_hint_default(const struct super_block *s,
+                           const reiser4_block_nr * block)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+
+       assert("nikita-3342", !reiser4_blocknr_is_fake(block));
+
+       spin_lock_reiser4_super(sbinfo);
+       if (*block < sbinfo->block_count) {
+               sbinfo->blocknr_hint_default = *block;
+       } else {
+               warning("zam-676",
+                       "block number %llu is too large to be used in a blocknr hint\n",
+                       (unsigned long long)*block);
+               dump_stack();
+               DEBUGON(1);
+       }
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* get current value of the default blocknr hint. */
+void get_blocknr_hint_default(reiser4_block_nr * result)
+{
+       reiser4_super_info_data *sbinfo = get_current_super_private();
+
+       spin_lock_reiser4_super(sbinfo);
+       *result = sbinfo->blocknr_hint_default;
+       assert("zam-677", *result < sbinfo->block_count);
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* Allocate "real" disk blocks by calling a proper space allocation plugin
+ * method. Blocks are allocated in one contiguous disk region. The plugin
+ * independent part accounts blocks by subtracting allocated amount from grabbed
+ * or fake block counter and add the same amount to the counter of allocated
+ * blocks.
+ *
+ * @hint -- a reiser4 blocknr hint object which contains further block
+ *          allocation hints and parameters (search start, a stage of block
+ *          which will be mapped to disk, etc.),
+ * @blk  -- an out parameter for the beginning of the allocated region,
+ * @len  -- in/out parameter, it should contain the maximum number of allocated
+ *          blocks, after block allocation completes, it contains the length of
+ *          allocated disk region.
+ * @flags -- see reiser4_ba_flags_t description.
+ *
+ * @return -- 0 if success, error code otherwise.
+ */
+int
+reiser4_alloc_blocks(reiser4_blocknr_hint * hint, reiser4_block_nr * blk,
+                    reiser4_block_nr * len, reiser4_ba_flags_t flags)
+{
+       __u64 needed = *len;
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+       int ret;
+
+       assert("zam-986", hint != NULL);
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       /* For write-optimized data we use default search start value, which is
+        * close to last write location. */
+       if (flags & BA_USE_DEFAULT_SEARCH_START) {
+               get_blocknr_hint_default(&hint->blk);
+       }
+
+       /* VITALY: allocator should grab this for internal/tx-lists/similar only. */
+/* VS-FIXME-HANS: why is this comment above addressed to vitaly (from vitaly)? */
+       if (hint->block_stage == BLOCK_NOT_COUNTED) {
+               ret = reiser4_grab_space_force(*len, flags);
+               if (ret != 0)
+                       return ret;
+       }
+
+       ret =
+           sa_alloc_blocks(reiser4_get_space_allocator(ctx->super),
+                           hint, (int)needed, blk, len);
+
+       if (!ret) {
+               assert("zam-680", *blk < reiser4_block_count(ctx->super));
+               assert("zam-681",
+                      *blk + *len <= reiser4_block_count(ctx->super));
+
+               if (flags & BA_PERMANENT) {
+                       /* we assume that current atom exists at this moment */
+                       txn_atom *atom = get_current_atom_locked();
+                       atom->nr_blocks_allocated += *len;
+                       spin_unlock_atom(atom);
+               }
+
+               switch (hint->block_stage) {
+               case BLOCK_NOT_COUNTED:
+               case BLOCK_GRABBED:
+                       grabbed2used(ctx, sbinfo, *len);
+                       break;
+               case BLOCK_UNALLOCATED:
+                       fake_allocated2used(sbinfo, *len, flags);
+                       break;
+               case BLOCK_FLUSH_RESERVED:
+                       {
+                               txn_atom *atom = get_current_atom_locked();
+                               flush_reserved2used(atom, *len);
+                               spin_unlock_atom(atom);
+                       }
+                       break;
+               default:
+                       impossible("zam-531", "wrong block stage");
+               }
+       } else {
+               assert("zam-821",
+                      ergo(hint->max_dist == 0
+                           && !hint->backward, ret != -ENOSPC));
+               if (hint->block_stage == BLOCK_NOT_COUNTED)
+                       grabbed2free(ctx, sbinfo, needed);
+       }
+
+       return ret;
+}
+
+/* used -> fake_allocated -> grabbed -> free */
+
+/* adjust sb block counters when @count unallocated blocks get unmapped from
+   disk */
+static void
+used2fake_allocated(reiser4_super_info_data * sbinfo, __u64 count,
+                   int formatted)
+{
+       spin_lock_reiser4_super(sbinfo);
+
+       if (formatted)
+               sbinfo->blocks_fake_allocated += count;
+       else
+               sbinfo->blocks_fake_allocated_unformatted += count;
+
+       sub_from_sb_used(sbinfo, count);
+
+       assert("nikita-2681",
+              reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+static void
+used2flush_reserved(reiser4_super_info_data * sbinfo, txn_atom * atom,
+                   __u64 count, reiser4_ba_flags_t flags UNUSED_ARG)
+{
+       assert("nikita-2791", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       add_to_atom_flush_reserved_nolock(atom, (__u32) count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sbinfo->blocks_flush_reserved += count;
+       /*add_to_sb_flush_reserved(sbinfo, count); */
+       sub_from_sb_used(sbinfo, count);
+
+       assert("nikita-2681",
+              reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* disk space, virtually used by fake block numbers is counted as "grabbed" again. */
+static void
+fake_allocated2grabbed(reiser4_context * ctx, reiser4_super_info_data * sbinfo,
+                      __u64 count, reiser4_ba_flags_t flags)
+{
+       add_to_ctx_grabbed(ctx, count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       assert("nikita-2682", reiser4_check_block_counters(ctx->super));
+
+       sbinfo->blocks_grabbed += count;
+       sub_from_sb_fake_allocated(sbinfo, count, flags & BA_FORMATTED);
+
+       assert("nikita-2683", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+void fake_allocated2free(__u64 count, reiser4_ba_flags_t flags)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       fake_allocated2grabbed(ctx, sbinfo, count, flags);
+       grabbed2free(ctx, sbinfo, count);
+}
+
+void grabbed2free_mark(__u64 mark)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       assert("nikita-3007", (__s64) mark >= 0);
+       assert("nikita-3006", ctx->grabbed_blocks >= mark);
+       grabbed2free(ctx, sbinfo, ctx->grabbed_blocks - mark);
+}
+
+/**
+ * grabbed2free - adjust grabbed and free block counters
+ * @ctx: context to update grabbed block counter of
+ * @sbinfo: super block to update grabbed and free block counters of
+ * @count: number of blocks to adjust counters by
+ *
+ * Decreases context's and per filesystem's counters of grabbed
+ * blocks. Increases per filesystem's counter of free blocks.
+ */
+void grabbed2free(reiser4_context *ctx, reiser4_super_info_data *sbinfo,
+                 __u64 count)
+{
+       sub_from_ctx_grabbed(ctx, count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sub_from_sb_grabbed(sbinfo, count);
+       sbinfo->blocks_free += count;
+       assert("nikita-2684", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+void grabbed2flush_reserved_nolock(txn_atom * atom, __u64 count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       assert("vs-1095", atom);
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       sub_from_ctx_grabbed(ctx, count);
+
+       add_to_atom_flush_reserved_nolock(atom, count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sbinfo->blocks_flush_reserved += count;
+       sub_from_sb_grabbed(sbinfo, count);
+
+       assert("vpf-292", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+void grabbed2flush_reserved(__u64 count)
+{
+       txn_atom *atom = get_current_atom_locked();
+
+       grabbed2flush_reserved_nolock(atom, count);
+
+       spin_unlock_atom(atom);
+}
+
+void flush_reserved2grabbed(txn_atom * atom, __u64 count)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       assert("nikita-2788", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       add_to_ctx_grabbed(ctx, count);
+
+       sub_from_atom_flush_reserved_nolock(atom, (__u32) count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sbinfo->blocks_grabbed += count;
+       sub_from_sb_flush_reserved(sbinfo, count);
+
+       assert("vpf-292", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/**
+ * all_grabbed2free - releases all blocks grabbed in context
+ *
+ * Decreases context's and super block's grabbed block counters by number of
+ * blocks grabbed by current context and increases super block's free block
+ * counter correspondingly.
+ */
+void all_grabbed2free(void)
+{
+       reiser4_context *ctx = get_current_context();
+
+       grabbed2free(ctx, get_super_private(ctx->super), ctx->grabbed_blocks);
+}
+
+/* adjust sb block counters if real (on-disk) blocks do not become unallocated
+   after freeing, @count blocks become "grabbed". */
+static void
+used2grabbed(reiser4_context * ctx, reiser4_super_info_data * sbinfo,
+            __u64 count)
+{
+       add_to_ctx_grabbed(ctx, count);
+
+       spin_lock_reiser4_super(sbinfo);
+
+       sbinfo->blocks_grabbed += count;
+       sub_from_sb_used(sbinfo, count);
+
+       assert("nikita-2685", reiser4_check_block_counters(ctx->super));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+/* this used to be done through used2grabbed and grabbed2free*/
+static void used2free(reiser4_super_info_data * sbinfo, __u64 count)
+{
+       spin_lock_reiser4_super(sbinfo);
+
+       sbinfo->blocks_free += count;
+       sub_from_sb_used(sbinfo, count);
+
+       assert("nikita-2685",
+              reiser4_check_block_counters(reiser4_get_current_sb()));
+
+       spin_unlock_reiser4_super(sbinfo);
+}
+
+#if REISER4_DEBUG
+
+/* check "allocated" state of given block range */
+static void
+reiser4_check_blocks(const reiser4_block_nr * start,
+                    const reiser4_block_nr * len, int desired)
+{
+       sa_check_blocks(start, len, desired);
+}
+
+/* check "allocated" state of given block */
+void reiser4_check_block(const reiser4_block_nr * block, int desired)
+{
+       const reiser4_block_nr one = 1;
+
+       reiser4_check_blocks(block, &one, desired);
+}
+
+#endif
+
+/* Blocks deallocation function may do an actual deallocation through space
+   plugin allocation or store deleted block numbers in atom's delete_set data
+   structure depend on @defer parameter. */
+
+/* if BA_DEFER bit is not turned on, @target_stage means the stage of blocks which
+   will be deleted from WORKING bitmap. They might be just unmapped from disk, or
+   freed but disk space is still grabbed by current thread, or these blocks must
+   not be counted in any reiser4 sb block counters, see block_stage_t comment */
+
+/* BA_FORMATTED bit is only used when BA_DEFER in not present: it is used to
+   distinguish blocks allocated for unformatted and formatted nodes */
+
+int
+reiser4_dealloc_blocks(const reiser4_block_nr * start,
+                      const reiser4_block_nr * len,
+                      block_stage_t target_stage, reiser4_ba_flags_t flags)
+{
+       txn_atom *atom = NULL;
+       int ret;
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       if (REISER4_DEBUG) {
+               assert("zam-431", *len != 0);
+               assert("zam-432", *start != 0);
+               assert("zam-558", !reiser4_blocknr_is_fake(start));
+
+               spin_lock_reiser4_super(sbinfo);
+               assert("zam-562", *start < sbinfo->block_count);
+               spin_unlock_reiser4_super(sbinfo);
+       }
+
+       if (flags & BA_DEFER) {
+               blocknr_set_entry *bsep = NULL;
+
+               /* storing deleted block numbers in a blocknr set
+                  datastructure for further actual deletion */
+               do {
+                       atom = get_current_atom_locked();
+                       assert("zam-430", atom != NULL);
+
+                       ret =
+                           blocknr_set_add_extent(atom, &atom->delete_set,
+                                                  &bsep, start, len);
+
+                       if (ret == -ENOMEM)
+                               return ret;
+
+                       /* This loop might spin at most two times */
+               } while (ret == -E_REPEAT);
+
+               assert("zam-477", ret == 0);
+               assert("zam-433", atom != NULL);
+
+               spin_unlock_atom(atom);
+
+       } else {
+               assert("zam-425", get_current_super_private() != NULL);
+               sa_dealloc_blocks(reiser4_get_space_allocator(ctx->super),
+                                 *start, *len);
+
+               if (flags & BA_PERMANENT) {
+                       /* These blocks were counted as allocated, we have to revert it
+                        * back if allocation is discarded. */
+                       txn_atom *atom = get_current_atom_locked();
+                       atom->nr_blocks_allocated -= *len;
+                       spin_unlock_atom(atom);
+               }
+
+               switch (target_stage) {
+               case BLOCK_NOT_COUNTED:
+                       assert("vs-960", flags & BA_FORMATTED);
+                       /* VITALY: This is what was grabbed for internal/tx-lists/similar only */
+                       used2free(sbinfo, *len);
+                       break;
+
+               case BLOCK_GRABBED:
+                       used2grabbed(ctx, sbinfo, *len);
+                       break;
+
+               case BLOCK_UNALLOCATED:
+                       used2fake_allocated(sbinfo, *len, flags & BA_FORMATTED);
+                       break;
+
+               case BLOCK_FLUSH_RESERVED:{
+                               txn_atom *atom;
+
+                               atom = get_current_atom_locked();
+                               used2flush_reserved(sbinfo, atom, *len,
+                                                   flags & BA_FORMATTED);
+                               spin_unlock_atom(atom);
+                               break;
+                       }
+               default:
+                       impossible("zam-532", "wrong block stage");
+               }
+       }
+
+       return 0;
+}
+
+/* wrappers for block allocator plugin methods */
+int reiser4_pre_commit_hook(void)
+{
+       assert("zam-502", get_current_super_private() != NULL);
+       sa_pre_commit_hook();
+       return 0;
+}
+
+/* an actor which applies delete set to block allocator data */
+static int
+apply_dset(txn_atom * atom UNUSED_ARG, const reiser4_block_nr * a,
+          const reiser4_block_nr * b, void *data UNUSED_ARG)
+{
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       __u64 len = 1;
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       assert("zam-877", atom->stage >= ASTAGE_PRE_COMMIT);
+       assert("zam-552", sbinfo != NULL);
+
+       if (b != NULL)
+               len = *b;
+
+       if (REISER4_DEBUG) {
+               spin_lock_reiser4_super(sbinfo);
+
+               assert("zam-554", *a < reiser4_block_count(ctx->super));
+               assert("zam-555", *a + len <= reiser4_block_count(ctx->super));
+
+               spin_unlock_reiser4_super(sbinfo);
+       }
+
+       sa_dealloc_blocks(&sbinfo->space_allocator, *a, len);
+       /* adjust sb block counters */
+       used2free(sbinfo, len);
+       return 0;
+}
+
+void reiser4_post_commit_hook(void)
+{
+       txn_atom *atom;
+
+       atom = get_current_atom_locked();
+       assert("zam-452", atom->stage == ASTAGE_POST_COMMIT);
+       spin_unlock_atom(atom);
+
+       /* do the block deallocation which was deferred
+          until commit is done */
+       blocknr_set_iterator(atom, &atom->delete_set, apply_dset, NULL, 1);
+
+       assert("zam-504", get_current_super_private() != NULL);
+       sa_post_commit_hook();
+}
+
+void reiser4_post_write_back_hook(void)
+{
+       assert("zam-504", get_current_super_private() != NULL);
+
+       sa_post_commit_hook();
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/block_alloc.h linux-2.6.20/fs/reiser4/block_alloc.h
--- linux-2.6.20.orig/fs/reiser4/block_alloc.h  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/block_alloc.h       2007-05-06 14:50:43.682970725 +0400
@@ -0,0 +1,175 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined (__FS_REISER4_BLOCK_ALLOC_H__)
+#define __FS_REISER4_BLOCK_ALLOC_H__
+
+#include "dformat.h"
+#include "forward.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>
+
+/* Mask when is applied to given block number shows is that block number is a fake one */
+#define REISER4_FAKE_BLOCKNR_BIT_MASK   0x8000000000000000ULL
+/* Mask which isolates a type of object this fake block number was assigned to */
+#define REISER4_BLOCKNR_STATUS_BIT_MASK 0xC000000000000000ULL
+
+/*result after applying the REISER4_BLOCKNR_STATUS_BIT_MASK should be compared
+   against these two values to understand is the object unallocated or bitmap
+   shadow object (WORKING BITMAP block, look at the plugin/space/bitmap.c) */
+#define REISER4_UNALLOCATED_STATUS_VALUE    0xC000000000000000ULL
+#define REISER4_BITMAP_BLOCKS_STATUS_VALUE  0x8000000000000000ULL
+
+/* specification how block allocation was counted in sb block counters */
+typedef enum {
+       BLOCK_NOT_COUNTED = 0,  /* reiser4 has no info about this block yet */
+       BLOCK_GRABBED = 1,      /* free space grabbed for further allocation
+                                  of this block */
+       BLOCK_FLUSH_RESERVED = 2,       /* block is reserved for flush needs. */
+       BLOCK_UNALLOCATED = 3,  /* block is used for existing in-memory object
+                                  ( unallocated formatted or unformatted
+                                  node) */
+       BLOCK_ALLOCATED = 4     /* block is mapped to disk, real on-disk block
+                                  number assigned */
+} block_stage_t;
+
+/* a hint for block allocator */
+struct reiser4_blocknr_hint {
+       /* FIXME: I think we want to add a longterm lock on the bitmap block here.  This
+          is to prevent jnode_flush() calls from interleaving allocations on the same
+          bitmap, once a hint is established. */
+
+       /* search start hint */
+       reiser4_block_nr blk;
+       /* if not zero, it is a region size we search for free blocks in */
+       reiser4_block_nr max_dist;
+       /* level for allocation, may be useful have branch-level and higher
+          write-optimized. */
+       tree_level level;
+       /* block allocator assumes that blocks, which will be mapped to disk,
+          are in this specified block_stage */
+       block_stage_t block_stage;
+       /* If direction = 1 allocate blocks in backward direction from the end
+        * of disk to the beginning of disk.  */
+       unsigned int backward:1;
+
+};
+
+/* These flags control block allocation/deallocation behavior */
+enum reiser4_ba_flags {
+       /* do allocatations from reserved (5%) area */
+       BA_RESERVED = (1 << 0),
+
+       /* block allocator can do commit trying to recover free space */
+       BA_CAN_COMMIT = (1 << 1),
+
+       /* if operation will be applied to formatted block */
+       BA_FORMATTED = (1 << 2),
+
+       /* defer actual block freeing until transaction commit */
+       BA_DEFER = (1 << 3),
+
+       /* allocate blocks for permanent fs objects (formatted or unformatted), not
+          wandered of log blocks */
+       BA_PERMANENT = (1 << 4),
+
+       /* grab space even it was disabled */
+       BA_FORCE = (1 << 5),
+
+       /* use default start value for free blocks search. */
+       BA_USE_DEFAULT_SEARCH_START = (1 << 6)
+};
+
+typedef enum reiser4_ba_flags reiser4_ba_flags_t;
+
+extern void reiser4_blocknr_hint_init(reiser4_blocknr_hint * hint);
+extern void reiser4_blocknr_hint_done(reiser4_blocknr_hint * hint);
+extern void update_blocknr_hint_default(const struct super_block *,
+                                       const reiser4_block_nr *);
+extern void get_blocknr_hint_default(reiser4_block_nr *);
+
+extern reiser4_block_nr reiser4_fs_reserved_space(struct super_block *super);
+
+int assign_fake_blocknr_formatted(reiser4_block_nr *);
+reiser4_block_nr fake_blocknr_unformatted(int);
+
+/* free -> grabbed -> fake_allocated -> used */
+
+int reiser4_grab_space(__u64 count, reiser4_ba_flags_t flags);
+void all_grabbed2free(void);
+void grabbed2free(reiser4_context *, reiser4_super_info_data *, __u64 count);
+void fake_allocated2free(__u64 count, reiser4_ba_flags_t flags);
+void grabbed2flush_reserved_nolock(txn_atom * atom, __u64 count);
+void grabbed2flush_reserved(__u64 count);
+int reiser4_alloc_blocks(reiser4_blocknr_hint * hint,
+                        reiser4_block_nr * start,
+                        reiser4_block_nr * len, reiser4_ba_flags_t flags);
+int reiser4_dealloc_blocks(const reiser4_block_nr *,
+                          const reiser4_block_nr *,
+                          block_stage_t, reiser4_ba_flags_t flags);
+
+static inline int reiser4_alloc_block(reiser4_blocknr_hint * hint,
+                                     reiser4_block_nr * start,
+                                     reiser4_ba_flags_t flags)
+{
+       reiser4_block_nr one = 1;
+       return reiser4_alloc_blocks(hint, start, &one, flags);
+}
+
+static inline int reiser4_dealloc_block(const reiser4_block_nr * block,
+                                       block_stage_t stage,
+                                       reiser4_ba_flags_t flags)
+{
+       const reiser4_block_nr one = 1;
+       return reiser4_dealloc_blocks(block, &one, stage, flags);
+}
+
+#define reiser4_grab_space_force(count, flags)         \
+       reiser4_grab_space(count, flags | BA_FORCE)
+
+extern void grabbed2free_mark(__u64 mark);
+extern int reiser4_grab_reserved(struct super_block *,
+                                __u64, reiser4_ba_flags_t);
+extern void reiser4_release_reserved(struct super_block *super);
+
+/* grabbed -> fake_allocated */
+
+/* fake_allocated -> used */
+
+/* used -> fake_allocated -> grabbed -> free */
+
+extern void flush_reserved2grabbed(txn_atom * atom, __u64 count);
+
+extern int reiser4_blocknr_is_fake(const reiser4_block_nr * da);
+
+extern void grabbed2cluster_reserved(int count);
+extern void cluster_reserved2grabbed(int count);
+extern void cluster_reserved2free(int count);
+
+extern int reiser4_check_block_counters(const struct super_block *);
+
+#if REISER4_DEBUG
+
+extern void reiser4_check_block(const reiser4_block_nr *, int);
+
+#else
+
+#  define reiser4_check_block(beg, val)        noop
+
+#endif
+
+extern int reiser4_pre_commit_hook(void);
+extern void reiser4_post_commit_hook(void);
+extern void reiser4_post_write_back_hook(void);
+
+#endif                         /* __FS_REISER4_BLOCK_ALLOC_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/blocknrset.c linux-2.6.20/fs/reiser4/blocknrset.c
--- linux-2.6.20.orig/fs/reiser4/blocknrset.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/blocknrset.c        2007-05-06 14:50:43.686971975 +0400
@@ -0,0 +1,368 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* This file contains code for various block number sets used by the atom to
+   track the deleted set and wandered block mappings. */
+
+#include "debug.h"
+#include "dformat.h"
+#include "txnmgr.h"
+#include "context.h"
+
+#include <linux/slab.h>
+
+/* The proposed data structure for storing unordered block number sets is a
+   list of elements, each of which contains an array of block number or/and
+   array of block number pairs. That element called blocknr_set_entry is used
+   to store block numbers from the beginning and for extents from the end of
+   the data field (char data[...]). The ->nr_blocks and ->nr_pairs fields
+   count numbers of blocks and extents.
+
+   +------------------- blocknr_set_entry->data ------------------+
+   |block1|block2| ... <free space> ... |pair3|pair2|pair1|
+   +------------------------------------------------------------+
+
+   When current blocknr_set_entry is full, allocate a new one. */
+
+/* Usage examples: blocknr sets are used in reiser4 for storing atom's delete
+ * set (single blocks and block extents), in that case blocknr pair represent an
+ * extent; atom's wandered map is also stored as a blocknr set, blocknr pairs
+ * there represent a (real block) -> (wandered block) mapping. */
+
+/* Protection: blocknr sets belong to reiser4 atom, and
+ * their modifications are performed with the atom lock held */
+
+typedef struct blocknr_pair blocknr_pair;
+
+/* The total size of a blocknr_set_entry. */
+#define BLOCKNR_SET_ENTRY_SIZE 128
+
+/* The number of blocks that can fit the blocknr data area. */
+#define BLOCKNR_SET_ENTRIES_NUMBER             \
+       ((BLOCKNR_SET_ENTRY_SIZE -              \
+         2 * sizeof (unsigned) -               \
+         sizeof(struct list_head)) /           \
+        sizeof(reiser4_block_nr))
+
+/* An entry of the blocknr_set */
+struct blocknr_set_entry {
+       unsigned nr_singles;
+       unsigned nr_pairs;
+       struct list_head link;
+       reiser4_block_nr entries[BLOCKNR_SET_ENTRIES_NUMBER];
+};
+
+/* A pair of blocks as recorded in the blocknr_set_entry data. */
+struct blocknr_pair {
+       reiser4_block_nr a;
+       reiser4_block_nr b;
+};
+
+/* Return the number of blocknr slots available in a blocknr_set_entry. */
+/* Audited by: green(2002.06.11) */
+static unsigned bse_avail(blocknr_set_entry * bse)
+{
+       unsigned used = bse->nr_singles + 2 * bse->nr_pairs;
+
+       assert("jmacd-5088", BLOCKNR_SET_ENTRIES_NUMBER >= used);
+       cassert(sizeof(blocknr_set_entry) == BLOCKNR_SET_ENTRY_SIZE);
+
+       return BLOCKNR_SET_ENTRIES_NUMBER - used;
+}
+
+/* Initialize a blocknr_set_entry. */
+static void bse_init(blocknr_set_entry *bse)
+{
+       bse->nr_singles = 0;
+       bse->nr_pairs = 0;
+       INIT_LIST_HEAD(&bse->link);
+}
+
+/* Allocate and initialize a blocknr_set_entry. */
+/* Audited by: green(2002.06.11) */
+static blocknr_set_entry *bse_alloc(void)
+{
+       blocknr_set_entry *e;
+
+       if ((e = (blocknr_set_entry *) kmalloc(sizeof(blocknr_set_entry),
+                                          reiser4_ctx_gfp_mask_get())) == NULL)
+               return NULL;
+
+       bse_init(e);
+
+       return e;
+}
+
+/* Free a blocknr_set_entry. */
+/* Audited by: green(2002.06.11) */
+static void bse_free(blocknr_set_entry * bse)
+{
+       kfree(bse);
+}
+
+/* Add a block number to a blocknr_set_entry */
+/* Audited by: green(2002.06.11) */
+static void
+bse_put_single(blocknr_set_entry * bse, const reiser4_block_nr * block)
+{
+       assert("jmacd-5099", bse_avail(bse) >= 1);
+
+       bse->entries[bse->nr_singles++] = *block;
+}
+
+/* Get a pair of block numbers */
+/* Audited by: green(2002.06.11) */
+static inline blocknr_pair *bse_get_pair(blocknr_set_entry * bse, unsigned pno)
+{
+       assert("green-1", BLOCKNR_SET_ENTRIES_NUMBER >= 2 * (pno + 1));
+
+       return (blocknr_pair *) (bse->entries + BLOCKNR_SET_ENTRIES_NUMBER -
+                                2 * (pno + 1));
+}
+
+/* Add a pair of block numbers to a blocknr_set_entry */
+/* Audited by: green(2002.06.11) */
+static void
+bse_put_pair(blocknr_set_entry * bse, const reiser4_block_nr * a,
+            const reiser4_block_nr * b)
+{
+       blocknr_pair *pair;
+
+       assert("jmacd-5100", bse_avail(bse) >= 2 && a != NULL && b != NULL);
+
+       pair = bse_get_pair(bse, bse->nr_pairs++);
+
+       pair->a = *a;
+       pair->b = *b;
+}
+
+/* Add either a block or pair of blocks to the block number set.  The first
+   blocknr (@a) must be non-NULL.  If @b is NULL a single blocknr is added, if
+   @b is non-NULL a pair is added.  The block number set belongs to atom, and
+   the call is made with the atom lock held.  There may not be enough space in
+   the current blocknr_set_entry.  If new_bsep points to a non-NULL
+   blocknr_set_entry then it will be added to the blocknr_set and new_bsep
+   will be set to NULL.  If new_bsep contains NULL then the atom lock will be
+   released and a new bse will be allocated in new_bsep.  E_REPEAT will be
+   returned with the atom unlocked for the operation to be tried again.  If
+   the operation succeeds, 0 is returned.  If new_bsep is non-NULL and not
+   used during the call, it will be freed automatically. */
+static int blocknr_set_add(txn_atom *atom, struct list_head *bset,
+                          blocknr_set_entry **new_bsep, const reiser4_block_nr *a,
+                          const reiser4_block_nr *b)
+{
+       blocknr_set_entry *bse;
+       unsigned entries_needed;
+
+       assert("jmacd-5101", a != NULL);
+
+       entries_needed = (b == NULL) ? 1 : 2;
+       if (list_empty(bset) ||
+           bse_avail(list_entry(bset->next, blocknr_set_entry, link)) < entries_needed) {
+               /* See if a bse was previously allocated. */
+               if (*new_bsep == NULL) {
+                       spin_unlock_atom(atom);
+                       *new_bsep = bse_alloc();
+                       return (*new_bsep != NULL) ? -E_REPEAT :
+                               RETERR(-ENOMEM);
+               }
+
+               /* Put it on the head of the list. */
+               list_add(&((*new_bsep)->link), bset);
+
+               *new_bsep = NULL;
+       }
+
+       /* Add the single or pair. */
+       bse = list_entry(bset->next, blocknr_set_entry, link);
+       if (b == NULL) {
+               bse_put_single(bse, a);
+       } else {
+               bse_put_pair(bse, a, b);
+       }
+
+       /* If new_bsep is non-NULL then there was an allocation race, free this copy. */
+       if (*new_bsep != NULL) {
+               bse_free(*new_bsep);
+               *new_bsep = NULL;
+       }
+
+       return 0;
+}
+
+/* Add an extent to the block set.  If the length is 1, it is treated as a
+   single block (e.g., reiser4_set_add_block). */
+/* Audited by: green(2002.06.11) */
+/* Auditor note: Entire call chain cannot hold any spinlocks, because
+   kmalloc might schedule. The only exception is atom spinlock, which is
+   properly freed. */
+int
+blocknr_set_add_extent(txn_atom * atom,
+                      struct list_head * bset,
+                      blocknr_set_entry ** new_bsep,
+                      const reiser4_block_nr * start,
+                      const reiser4_block_nr * len)
+{
+       assert("jmacd-5102", start != NULL && len != NULL && *len > 0);
+       return blocknr_set_add(atom, bset, new_bsep, start,
+                              *len == 1 ? NULL : len);
+}
+
+/* Add a block pair to the block set. It adds exactly a pair, which is checked
+ * by an assertion that both arguments are not null.*/
+/* Audited by: green(2002.06.11) */
+/* Auditor note: Entire call chain cannot hold any spinlocks, because
+   kmalloc might schedule. The only exception is atom spinlock, which is
+   properly freed. */
+int
+blocknr_set_add_pair(txn_atom * atom,
+                    struct list_head * bset,
+                    blocknr_set_entry ** new_bsep, const reiser4_block_nr * a,
+                    const reiser4_block_nr * b)
+{
+       assert("jmacd-5103", a != NULL && b != NULL);
+       return blocknr_set_add(atom, bset, new_bsep, a, b);
+}
+
+/* Initialize a blocknr_set. */
+void blocknr_set_init(struct list_head *bset)
+{
+       INIT_LIST_HEAD(bset);
+}
+
+/* Release the entries of a blocknr_set. */
+void blocknr_set_destroy(struct list_head *bset)
+{
+       blocknr_set_entry *bse;
+
+       while (!list_empty(bset)) {
+               bse = list_entry(bset->next, blocknr_set_entry, link);
+               list_del_init(&bse->link);
+               bse_free(bse);
+       }
+}
+
+/* Merge blocknr_set entries out of @from into @into. */
+/* Audited by: green(2002.06.11) */
+/* Auditor comments: This merge does not know if merged sets contain
+   blocks pairs (As for wandered sets) or extents, so it cannot really merge
+   overlapping ranges if there is some. So I believe it may lead to
+   some blocks being presented several times in one blocknr_set. To help
+   debugging such problems it might help to check for duplicate entries on
+   actual processing of this set. Testing this kind of stuff right here is
+   also complicated by the fact that these sets are not sorted and going
+   through whole set on each element addition is going to be CPU-heavy task */
+void blocknr_set_merge(struct list_head * from, struct list_head * into)
+{
+       blocknr_set_entry *bse_into = NULL;
+
+       /* If @from is empty, no work to perform. */
+       if (list_empty(from))
+               return;
+       /* If @into is not empty, try merging partial-entries. */
+       if (!list_empty(into)) {
+
+               /* Neither set is empty, pop the front to members and try to combine them. */
+               blocknr_set_entry *bse_from;
+               unsigned into_avail;
+
+               bse_into = list_entry(into->next, blocknr_set_entry, link);
+               list_del_init(&bse_into->link);
+               bse_from = list_entry(from->next, blocknr_set_entry, link);
+               list_del_init(&bse_from->link);
+
+               /* Combine singles. */
+               for (into_avail = bse_avail(bse_into);
+                    into_avail != 0 && bse_from->nr_singles != 0;
+                    into_avail -= 1) {
+                       bse_put_single(bse_into,
+                                      &bse_from->entries[--bse_from->
+                                                         nr_singles]);
+               }
+
+               /* Combine pairs. */
+               for (; into_avail > 1 && bse_from->nr_pairs != 0;
+                    into_avail -= 2) {
+                       blocknr_pair *pair =
+                           bse_get_pair(bse_from, --bse_from->nr_pairs);
+                       bse_put_pair(bse_into, &pair->a, &pair->b);
+               }
+
+               /* If bse_from is empty, delete it now. */
+               if (bse_avail(bse_from) == BLOCKNR_SET_ENTRIES_NUMBER) {
+                       bse_free(bse_from);
+               } else {
+                       /* Otherwise, bse_into is full or nearly full (e.g.,
+                          it could have one slot avail and bse_from has one
+                          pair left).  Push it back onto the list.  bse_from
+                          becomes bse_into, which will be the new partial. */
+                       list_add(&bse_into->link, into);
+                       bse_into = bse_from;
+               }
+       }
+
+       /* Splice lists together. */
+       list_splice_init(from, into->prev);
+
+       /* Add the partial entry back to the head of the list. */
+       if (bse_into != NULL)
+               list_add(&bse_into->link, into);
+}
+
+/* Iterate over all blocknr set elements. */
+int blocknr_set_iterator(txn_atom *atom, struct list_head *bset,
+                        blocknr_set_actor_f actor, void *data, int delete)
+{
+
+       blocknr_set_entry *entry;
+
+       assert("zam-429", atom != NULL);
+       assert("zam-430", atom_is_protected(atom));
+       assert("zam-431", bset != 0);
+       assert("zam-432", actor != NULL);
+
+       entry = list_entry(bset->next, blocknr_set_entry, link);
+       while (bset != &entry->link) {
+               blocknr_set_entry *tmp = list_entry(entry->link.next, blocknr_set_entry, link);
+               unsigned int i;
+               int ret;
+
+               for (i = 0; i < entry->nr_singles; i++) {
+                       ret = actor(atom, &entry->entries[i], NULL, data);
+
+                       /* We can't break a loop if delete flag is set. */
+                       if (ret != 0 && !delete)
+                               return ret;
+               }
+
+               for (i = 0; i < entry->nr_pairs; i++) {
+                       struct blocknr_pair *ab;
+
+                       ab = bse_get_pair(entry, i);
+
+                       ret = actor(atom, &ab->a, &ab->b, data);
+
+                       if (ret != 0 && !delete)
+                               return ret;
+               }
+
+               if (delete) {
+                       list_del(&entry->link);
+                       bse_free(entry);
+               }
+
+               entry = tmp;
+       }
+
+       return 0;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/carry.c linux-2.6.20/fs/reiser4/carry.c
--- linux-2.6.20.orig/fs/reiser4/carry.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/carry.c     2007-05-06 14:50:43.686971975 +0400
@@ -0,0 +1,1391 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* Functions to "carry" tree modification(s) upward. */
+/* Tree is modified one level at a time. As we modify a level we accumulate a
+   set of changes that need to be propagated to the next level.  We manage
+   node locking such that any searches that collide with carrying are
+   restarted, from the root if necessary.
+
+   Insertion of a new item may result in items being moved among nodes and
+   this requires the delimiting key to be updated at the least common parent
+   of the nodes modified to preserve search tree invariants. Also, insertion
+   may require allocation of a new node. A pointer to the new node has to be
+   inserted into some node on the parent level, etc.
+
+   Tree carrying is meant to be analogous to arithmetic carrying.
+
+   A carry operation is always associated with some node (&carry_node).
+
+   Carry process starts with some initial set of operations to be performed
+   and an initial set of already locked nodes.  Operations are performed one
+   by one. Performing each single operation has following possible effects:
+
+    - content of carry node associated with operation is modified
+    - new carry nodes are locked and involved into carry process on this level
+    - new carry operations are posted to the next level
+
+   After all carry operations on this level are done, process is repeated for
+   the accumulated sequence on carry operations for the next level. This
+   starts by trying to lock (in left to right order) all carry nodes
+   associated with carry operations on the parent level. After this, we decide
+   whether more nodes are required on the left of already locked set. If so,
+   all locks taken on the parent level are released, new carry nodes are
+   added, and locking process repeats.
+
+   It may happen that balancing process fails owing to unrecoverable error on
+   some of upper levels of a tree (possible causes are io error, failure to
+   allocate new node, etc.). In this case we should unmount the filesystem,
+   rebooting if it is the root, and possibly advise the use of fsck.
+
+   USAGE:
+
+    int some_tree_operation( znode *node, ... )
+    {
+       // Allocate on a stack pool of carry objects: operations and nodes.
+       // Most carry processes will only take objects from here, without
+       // dynamic allocation.
+
+I feel uneasy about this pool.  It adds to code complexity, I understand why it exists, but.... -Hans
+
+       carry_pool  pool;
+       carry_level lowest_level;
+       carry_op   *op;
+
+       init_carry_pool( &pool );
+       init_carry_level( &lowest_level, &pool );
+
+       // operation may be one of:
+       //   COP_INSERT    --- insert new item into node
+       //   COP_CUT       --- remove part of or whole node
+       //   COP_PASTE     --- increase size of item
+       //   COP_DELETE    --- delete pointer from parent node
+       //   COP_UPDATE    --- update delimiting key in least
+       //                     common ancestor of two
+
+       op = reiser4_post_carry( &lowest_level, operation, node, 0 );
+       if( IS_ERR( op ) || ( op == NULL ) ) {
+           handle error
+       } else {
+           // fill in remaining fields in @op, according to carry.h:carry_op
+           result = carry( &lowest_level, NULL );
+       }
+       done_carry_pool( &pool );
+    }
+
+   When you are implementing node plugin method that participates in carry
+   (shifting, insertion, deletion, etc.), do the following:
+
+   int foo_node_method( znode *node, ..., carry_level *todo )
+   {
+       carry_op   *op;
+
+       ....
+
+       // note, that last argument to reiser4_post_carry() is non-null
+       // here, because @op is to be applied to the parent of @node, rather
+       // than to the @node itself as in the previous case.
+
+       op = node_post_carry( todo, operation, node, 1 );
+       // fill in remaining fields in @op, according to carry.h:carry_op
+
+       ....
+
+   }
+
+   BATCHING:
+
+   One of the main advantages of level-by-level balancing implemented here is
+   ability to batch updates on a parent level and to peform them more
+   efficiently as a result.
+
+   Description To Be Done (TBD).
+
+   DIFFICULTIES AND SUBTLE POINTS:
+
+   1. complex plumbing is required, because:
+
+       a. effective allocation through pools is needed
+
+       b. target of operation is not exactly known when operation is
+       posted. This is worked around through bitfields in &carry_node and
+       logic in lock_carry_node()
+
+       c. of interaction with locking code: node should be added into sibling
+       list when pointer to it is inserted into its parent, which is some time
+       after node was created. Between these moments, node is somewhat in
+       suspended state and is only registered in the carry lists
+
+    2. whole balancing logic is implemented here, in particular, insertion
+    logic is coded in make_space().
+
+    3. special cases like insertion (reiser4_add_tree_root()) or deletion
+    (reiser4_kill_tree_root()) of tree root and morphing of paste into insert
+    (insert_paste()) have to be handled.
+
+    4. there is non-trivial interdependency between allocation of new nodes
+    and almost everything else. This is mainly due to the (1.c) above. I shall
+    write about this later.
+
+*/
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/item/extent.h"
+#include "plugin/node/node.h"
+#include "jnode.h"
+#include "znode.h"
+#include "tree_mod.h"
+#include "tree_walk.h"
+#include "block_alloc.h"
+#include "pool.h"
+#include "tree.h"
+#include "carry.h"
+#include "carry_ops.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/types.h>
+
+/* level locking/unlocking */
+static int lock_carry_level(carry_level * level);
+static void unlock_carry_level(carry_level * level, int failure);
+static void done_carry_level(carry_level * level);
+static void unlock_carry_node(carry_level * level, carry_node * node, int fail);
+
+int lock_carry_node(carry_level * level, carry_node * node);
+int lock_carry_node_tail(carry_node * node);
+
+/* carry processing proper */
+static int carry_on_level(carry_level * doing, carry_level * todo);
+
+static carry_op *add_op(carry_level * level, pool_ordering order,
+                       carry_op * reference);
+
+/* handlers for carry operations. */
+
+static void fatal_carry_error(carry_level * doing, int ecode);
+static int add_new_root(carry_level * level, carry_node * node, znode * fake);
+
+static void print_level(const char *prefix, carry_level * level);
+
+#if REISER4_DEBUG
+typedef enum {
+       CARRY_TODO,
+       CARRY_DOING
+} carry_queue_state;
+static int carry_level_invariant(carry_level * level, carry_queue_state state);
+#endif
+
+/* main entry point for tree balancing.
+
+   Tree carry performs operations from @doing and while doing so accumulates
+   information about operations to be performed on the next level ("carried"
+   to the parent level). Carried operations are performed, causing possibly
+   more operations to be carried upward etc. carry() takes care about
+   locking and pinning znodes while operating on them.
+
+   For usage, see comment at the top of fs/reiser4/carry.c
+
+*/
+int reiser4_carry(carry_level * doing /* set of carry operations to be
+                                      * performed */ ,
+                 carry_level * done  /* set of nodes, already performed
+                                      *  at the previous level.
+                                      * NULL in most cases */)
+{
+       int result = 0;
+       /* queue of new requests */
+       carry_level *todo;
+       ON_DEBUG(STORE_COUNTERS);
+
+       assert("nikita-888", doing != NULL);
+       BUG_ON(done != NULL);
+
+       todo = doing + 1;
+       init_carry_level(todo, doing->pool);
+
+       /* queue of requests preformed on the previous level */
+       done = todo + 1;
+       init_carry_level(done, doing->pool);
+
+       /* iterate until there is nothing more to do */
+       while (result == 0 && doing->ops_num > 0) {
+               carry_level *tmp;
+
+               /* at this point @done is locked. */
+               /* repeat lock/do/unlock while
+
+                  (1) lock_carry_level() fails due to deadlock avoidance, or
+
+                  (2) carry_on_level() decides that more nodes have to
+                  be involved.
+
+                  (3) some unexpected error occurred while balancing on the
+                  upper levels. In this case all changes are rolled back.
+
+                */
+               while (1) {
+                       result = lock_carry_level(doing);
+                       if (result == 0) {
+                               /* perform operations from @doing and
+                                  accumulate new requests in @todo */
+                               result = carry_on_level(doing, todo);
+                               if (result == 0)
+                                       break;
+                               else if (result != -E_REPEAT ||
+                                        !doing->restartable) {
+                                       warning("nikita-1043",
+                                               "Fatal error during carry: %i",
+                                               result);
+                                       print_level("done", done);
+                                       print_level("doing", doing);
+                                       print_level("todo", todo);
+                                       /* do some rough stuff like aborting
+                                          all pending transcrashes and thus
+                                          pushing tree back to the consistent
+                                          state. Alternatvely, just panic.
+                                        */
+                                       fatal_carry_error(doing, result);
+                                       return result;
+                               }
+                       } else if (result != -E_REPEAT) {
+                               fatal_carry_error(doing, result);
+                               return result;
+                       }
+                       unlock_carry_level(doing, 1);
+               }
+               /* at this point @done can be safely unlocked */
+               done_carry_level(done);
+
+               /* cyclically shift queues */
+               tmp = done;
+               done = doing;
+               doing = todo;
+               todo = tmp;
+               init_carry_level(todo, doing->pool);
+
+               /* give other threads chance to run */
+               reiser4_preempt_point();
+       }
+       done_carry_level(done);
+
+       /* all counters, but x_refs should remain the same. x_refs can change
+          owing to transaction manager */
+       ON_DEBUG(CHECK_COUNTERS);
+       return result;
+}
+
+/* perform carry operations on given level.
+
+   Optimizations proposed by pooh:
+
+   (1) don't lock all nodes from queue at the same time. Lock nodes lazily as
+   required;
+
+   (2) unlock node if there are no more operations to be performed upon it and
+   node didn't add any operation to @todo. This can be implemented by
+   attaching to each node two counters: counter of operaions working on this
+   node and counter and operations carried upward from this node.
+
+*/
+static int carry_on_level(carry_level * doing  /* queue of carry operations to
+                                                * do on this level */ ,
+                         carry_level * todo    /* queue where new carry
+                                                * operations to be performed on
+                                                * the * parent level are
+                                                * accumulated during @doing
+                                                * processing. */ )
+{
+       int result;
+       int (*f) (carry_op *, carry_level *, carry_level *);
+       carry_op *op;
+       carry_op *tmp_op;
+
+       assert("nikita-1034", doing != NULL);
+       assert("nikita-1035", todo != NULL);
+
+       /* @doing->nodes are locked. */
+
+       /* This function can be split into two phases: analysis and modification.
+
+          Analysis calculates precisely what items should be moved between
+          nodes. This information is gathered in some structures attached to
+          each carry_node in a @doing queue. Analysis also determines whether
+          new nodes are to be allocated etc.
+
+          After analysis is completed, actual modification is performed. Here
+          we can take advantage of "batch modification": if there are several
+          operations acting on the same node, modifications can be performed
+          more efficiently when batched together.
+
+          Above is an optimization left for the future.
+        */
+       /* Important, but delayed optimization: it's possible to batch
+          operations together and perform them more efficiently as a
+          result. For example, deletion of several neighboring items from a
+          node can be converted to a single ->cut() operation.
+
+          Before processing queue, it should be scanned and "mergeable"
+          operations merged.
+        */
+       result = 0;
+       for_all_ops(doing, op, tmp_op) {
+               carry_opcode opcode;
+
+               assert("nikita-1041", op != NULL);
+               opcode = op->op;
+               assert("nikita-1042", op->op < COP_LAST_OP);
+               f = op_dispatch_table[op->op].handler;
+               result = f(op, doing, todo);
+               /* locking can fail with -E_REPEAT. Any different error is fatal
+                  and will be handled by fatal_carry_error() sledgehammer.
+                */
+               if (result != 0)
+                       break;
+       }
+       if (result == 0) {
+               carry_plugin_info info;
+               carry_node *scan;
+               carry_node *tmp_scan;
+
+               info.doing = doing;
+               info.todo = todo;
+
+               assert("nikita-3002",
+                      carry_level_invariant(doing, CARRY_DOING));
+               for_all_nodes(doing, scan, tmp_scan) {
+                       znode *node;
+
+                       node = reiser4_carry_real(scan);
+                       assert("nikita-2547", node != NULL);
+                       if (node_is_empty(node)) {
+                               result =
+                                   node_plugin_by_node(node)->
+                                   prepare_removal(node, &info);
+                               if (result != 0)
+                                       break;
+                       }
+               }
+       }
+       return result;
+}
+
+/* post carry operation
+
+   This is main function used by external carry clients: node layout plugins
+   and tree operations to create new carry operation to be performed on some
+   level.
+
+   New operation will be included in the @level queue. To actually perform it,
+   call carry( level, ... ). This function takes write lock on @node. Carry
+   manages all its locks by itself, don't worry about this.
+
+   This function adds operation and node at the end of the queue. It is up to
+   caller to guarantee proper ordering of node queue.
+
+*/
+carry_op * reiser4_post_carry(carry_level * level /* queue where new operation
+                                                  * is to be posted at */ ,
+                             carry_opcode op /* opcode of operation */ ,
+                             znode * node      /* node on which this operation
+                                                * will operate */ ,
+                             int apply_to_parent_p /* whether operation will
+                                                    * operate directly on @node
+                                                    * or on it parent. */)
+{
+       carry_op *result;
+       carry_node *child;
+
+       assert("nikita-1046", level != NULL);
+       assert("nikita-1788", znode_is_write_locked(node));
+
+       result = add_op(level, POOLO_LAST, NULL);
+       if (IS_ERR(result))
+               return result;
+       child = reiser4_add_carry(level, POOLO_LAST, NULL);
+       if (IS_ERR(child)) {
+               reiser4_pool_free(&level->pool->op_pool, &result->header);
+               return (carry_op *) child;
+       }
+       result->node = child;
+       result->op = op;
+       child->parent = apply_to_parent_p;
+       if (ZF_ISSET(node, JNODE_ORPHAN))
+               child->left_before = 1;
+       child->node = node;
+       return result;
+}
+
+/* initialize carry queue */
+void init_carry_level(carry_level * level /* level to initialize */ ,
+                     carry_pool * pool /* pool @level will allocate objects
+                                        * from */ )
+{
+       assert("nikita-1045", level != NULL);
+       assert("nikita-967", pool != NULL);
+
+       memset(level, 0, sizeof *level);
+       level->pool = pool;
+
+       INIT_LIST_HEAD(&level->nodes);
+       INIT_LIST_HEAD(&level->ops);
+}
+
+/* allocate carry pool and initialize pools within queue */
+carry_pool *init_carry_pool(int size)
+{
+       carry_pool *pool;
+
+       assert("", size >= sizeof(carry_pool) + 3 * sizeof(carry_level));
+       pool = kmalloc(size, reiser4_ctx_gfp_mask_get());
+       if (pool == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+
+       reiser4_init_pool(&pool->op_pool, sizeof(carry_op), CARRIES_POOL_SIZE,
+                         (char *)pool->op);
+       reiser4_init_pool(&pool->node_pool, sizeof(carry_node),
+                         NODES_LOCKED_POOL_SIZE, (char *)pool->node);
+       return pool;
+}
+
+/* finish with queue pools */
+void done_carry_pool(carry_pool * pool /* pool to destroy */ )
+{
+       reiser4_done_pool(&pool->op_pool);
+       reiser4_done_pool(&pool->node_pool);
+       kfree(pool);
+}
+
+/* add new carry node to the @level.
+
+   Returns pointer to the new carry node allocated from pool.  It's up to
+   callers to maintain proper order in the @level. Assumption is that if carry
+   nodes on one level are already sorted and modifications are peroformed from
+   left to right, carry nodes added on the parent level will be ordered
+   automatically. To control ordering use @order and @reference parameters.
+
+*/
+carry_node *reiser4_add_carry_skip(carry_level * level /* &carry_level to add
+                                                        * node to */ ,
+                                  pool_ordering order  /* where to insert:
+                                                        * at the beginning of
+                                                        * @level,
+                                                        * before @reference,
+                                                        * after @reference,
+                                                        * at the end of @level
+                                                        */ ,
+                                  carry_node * reference/* reference node for
+                                                         * insertion */)
+{
+       ON_DEBUG(carry_node * orig_ref = reference);
+
+       if (order == POOLO_BEFORE) {
+               reference = find_left_carry(reference, level);
+               if (reference == NULL)
+                       reference = list_entry(level->nodes.next, carry_node,
+                                              header.level_linkage);
+               else
+                       reference = list_entry(reference->header.level_linkage.next,
+                                              carry_node, header.level_linkage);
+       } else if (order == POOLO_AFTER) {
+               reference = find_right_carry(reference, level);
+               if (reference == NULL)
+                       reference = list_entry(level->nodes.prev, carry_node,
+                                              header.level_linkage);
+               else
+                       reference = list_entry(reference->header.level_linkage.prev,
+                                              carry_node, header.level_linkage);
+       }
+       assert("nikita-2209",
+              ergo(orig_ref != NULL,
+                   reiser4_carry_real(reference) ==
+                   reiser4_carry_real(orig_ref)));
+       return reiser4_add_carry(level, order, reference);
+}
+
+carry_node *reiser4_add_carry(carry_level * level      /* &carry_level to add node
+                                                * to */ ,
+                     pool_ordering order       /* where to insert: at the
+                                                * beginning of @level, before
+                                                * @reference, after @reference,
+                                                * at the end of @level */ ,
+                     carry_node * reference    /* reference node for
+                                                * insertion */ )
+{
+       carry_node *result;
+
+       result =
+           (carry_node *) reiser4_add_obj(&level->pool->node_pool,
+                                          &level->nodes,
+                                          order, &reference->header);
+       if (!IS_ERR(result) && (result != NULL))
+               ++level->nodes_num;
+       return result;
+}
+
+/* add new carry operation to the @level.
+
+   Returns pointer to the new carry operations allocated from pool. It's up to
+   callers to maintain proper order in the @level. To control ordering use
+   @order and @reference parameters.
+
+*/
+static carry_op *add_op(carry_level * level /* &carry_level to add node to */ ,
+                       pool_ordering order     /* where to insert: at the beginning of
+                                                * @level, before @reference, after
+                                                * @reference, at the end of @level */ ,
+                       carry_op *
+                       reference /* reference node for insertion */ )
+{
+       carry_op *result;
+
+       result =
+           (carry_op *) reiser4_add_obj(&level->pool->op_pool, &level->ops,
+                                        order, &reference->header);
+       if (!IS_ERR(result) && (result != NULL))
+               ++level->ops_num;
+       return result;
+}
+
+/* Return node on the right of which @node was created.
+
+   Each node is created on the right of some existing node (or it is new root,
+   which is special case not handled here).
+
+   @node is new node created on some level, but not yet inserted into its
+   parent, it has corresponding bit (JNODE_ORPHAN) set in zstate.
+
+*/
+static carry_node *find_begetting_brother(carry_node * node    /* node to start search
+                                                                * from */ ,
+                                         carry_level * kin UNUSED_ARG  /* level to
+                                                                        * scan */ )
+{
+       carry_node *scan;
+
+       assert("nikita-1614", node != NULL);
+       assert("nikita-1615", kin != NULL);
+       assert("nikita-1616", LOCK_CNT_GTZ(rw_locked_tree));
+       assert("nikita-1619", ergo(reiser4_carry_real(node) != NULL,
+                                  ZF_ISSET(reiser4_carry_real(node),
+                                           JNODE_ORPHAN)));
+       for (scan = node;;
+            scan = list_entry(scan->header.level_linkage.prev, carry_node,
+                              header.level_linkage)) {
+               assert("nikita-1617", &kin->nodes != &scan->header.level_linkage);
+               if ((scan->node != node->node) &&
+                   !ZF_ISSET(scan->node, JNODE_ORPHAN)) {
+                       assert("nikita-1618", reiser4_carry_real(scan) != NULL);
+                       break;
+               }
+       }
+       return scan;
+}
+
+static cmp_t
+carry_node_cmp(carry_level * level, carry_node * n1, carry_node * n2)
+{
+       assert("nikita-2199", n1 != NULL);
+       assert("nikita-2200", n2 != NULL);
+
+       if (n1 == n2)
+               return EQUAL_TO;
+       while (1) {
+               n1 = carry_node_next(n1);
+               if (carry_node_end(level, n1))
+                       return GREATER_THAN;
+               if (n1 == n2)
+                       return LESS_THAN;
+       }
+       impossible("nikita-2201", "End of level reached");
+}
+
+carry_node *find_carry_node(carry_level * level, const znode * node)
+{
+       carry_node *scan;
+       carry_node *tmp_scan;
+
+       assert("nikita-2202", level != NULL);
+       assert("nikita-2203", node != NULL);
+
+       for_all_nodes(level, scan, tmp_scan) {
+               if (reiser4_carry_real(scan) == node)
+                       return scan;
+       }
+       return NULL;
+}
+
+znode *reiser4_carry_real(const carry_node * node)
+{
+       assert("nikita-3061", node != NULL);
+
+       return node->lock_handle.node;
+}
+
+carry_node *insert_carry_node(carry_level * doing, carry_level * todo,
+                             const znode * node)
+{
+       carry_node *base;
+       carry_node *scan;
+       carry_node *tmp_scan;
+       carry_node *proj;
+
+       base = find_carry_node(doing, node);
+       assert("nikita-2204", base != NULL);
+
+       for_all_nodes(todo, scan, tmp_scan) {
+               proj = find_carry_node(doing, scan->node);
+               assert("nikita-2205", proj != NULL);
+               if (carry_node_cmp(doing, proj, base) != LESS_THAN)
+                       break;
+       }
+       return scan;
+}
+
+static carry_node *add_carry_atplace(carry_level * doing, carry_level * todo,
+                                    znode * node)
+{
+       carry_node *reference;
+
+       assert("nikita-2994", doing != NULL);
+       assert("nikita-2995", todo != NULL);
+       assert("nikita-2996", node != NULL);
+
+       reference = insert_carry_node(doing, todo, node);
+       assert("nikita-2997", reference != NULL);
+
+       return reiser4_add_carry(todo, POOLO_BEFORE, reference);
+}
+
+/* like reiser4_post_carry(), but designed to be called from node plugin methods.
+   This function is different from reiser4_post_carry() in that it finds proper
+   place to insert node in the queue. */
+carry_op *node_post_carry(carry_plugin_info * info     /* carry parameters
+                                                        * passed down to node
+                                                        * plugin */ ,
+                         carry_opcode op /* opcode of operation */ ,
+                         znode * node  /* node on which this
+                                        * operation will operate */ ,
+                         int apply_to_parent_p /* whether operation will
+                                                * operate directly on @node
+                                                * or on it parent. */ )
+{
+       carry_op *result;
+       carry_node *child;
+
+       assert("nikita-2207", info != NULL);
+       assert("nikita-2208", info->todo != NULL);
+
+       if (info->doing == NULL)
+               return reiser4_post_carry(info->todo, op, node,
+                                         apply_to_parent_p);
+
+       result = add_op(info->todo, POOLO_LAST, NULL);
+       if (IS_ERR(result))
+               return result;
+       child = add_carry_atplace(info->doing, info->todo, node);
+       if (IS_ERR(child)) {
+               reiser4_pool_free(&info->todo->pool->op_pool, &result->header);
+               return (carry_op *) child;
+       }
+       result->node = child;
+       result->op = op;
+       child->parent = apply_to_parent_p;
+       if (ZF_ISSET(node, JNODE_ORPHAN))
+               child->left_before = 1;
+       child->node = node;
+       return result;
+}
+
+/* lock all carry nodes in @level */
+static int lock_carry_level(carry_level * level /* level to lock */ )
+{
+       int result;
+       carry_node *node;
+       carry_node *tmp_node;
+
+       assert("nikita-881", level != NULL);
+       assert("nikita-2229", carry_level_invariant(level, CARRY_TODO));
+
+       /* lock nodes from left to right */
+       result = 0;
+       for_all_nodes(level, node, tmp_node) {
+               result = lock_carry_node(level, node);
+               if (result != 0)
+                       break;
+       }
+       return result;
+}
+
+/* Synchronize delimiting keys between @node and its left neighbor.
+
+   To reduce contention on dk key and simplify carry code, we synchronize
+   delimiting keys only when carry ultimately leaves tree level (carrying
+   changes upward) and unlocks nodes at this level.
+
+   This function first finds left neighbor of @node and then updates left
+   neighbor's right delimiting key to conincide with least key in @node.
+
+*/
+
+ON_DEBUG(extern atomic_t delim_key_version;
+    )
+
+static void sync_dkeys(znode * spot /* node to update */ )
+{
+       reiser4_key pivot;
+       reiser4_tree *tree;
+
+       assert("nikita-1610", spot != NULL);
+       assert("nikita-1612", LOCK_CNT_NIL(rw_locked_dk));
+
+       tree = znode_get_tree(spot);
+       read_lock_tree(tree);
+       write_lock_dk(tree);
+
+       assert("nikita-2192", znode_is_loaded(spot));
+
+       /* sync left delimiting key of @spot with key in its leftmost item */
+       if (node_is_empty(spot))
+               pivot = *znode_get_rd_key(spot);
+       else
+               leftmost_key_in_node(spot, &pivot);
+
+       znode_set_ld_key(spot, &pivot);
+
+       /* there can be sequence of empty nodes pending removal on the left of
+          @spot. Scan them and update their left and right delimiting keys to
+          match left delimiting key of @spot. Also, update right delimiting
+          key of first non-empty left neighbor.
+        */
+       while (1) {
+               if (!ZF_ISSET(spot, JNODE_LEFT_CONNECTED))
+                       break;
+
+               spot = spot->left;
+               if (spot == NULL)
+                       break;
+
+               znode_set_rd_key(spot, &pivot);
+               /* don't sink into the domain of another balancing */
+               if (!znode_is_write_locked(spot))
+                       break;
+               if (ZF_ISSET(spot, JNODE_HEARD_BANSHEE))
+                       znode_set_ld_key(spot, &pivot);
+               else
+                       break;
+       }
+
+       write_unlock_dk(tree);
+       read_unlock_tree(tree);
+}
+
+/* unlock all carry nodes in @level */
+static void unlock_carry_level(carry_level * level /* level to unlock */ ,
+                              int failure      /* true if unlocking owing to
+                                                * failure */ )
+{
+       carry_node *node;
+       carry_node *tmp_node;
+
+       assert("nikita-889", level != NULL);
+
+       if (!failure) {
+               znode *spot;
+
+               spot = NULL;
+               /* update delimiting keys */
+               for_all_nodes(level, node, tmp_node) {
+                       if (reiser4_carry_real(node) != spot) {
+                               spot = reiser4_carry_real(node);
+                               sync_dkeys(spot);
+                       }
+               }
+       }
+
+       /* nodes can be unlocked in arbitrary order.  In preemptible
+          environment it's better to unlock in reverse order of locking,
+          though.
+        */
+       for_all_nodes_back(level, node, tmp_node) {
+               /* all allocated nodes should be already linked to their
+                  parents at this moment. */
+               assert("nikita-1631",
+                      ergo(!failure, !ZF_ISSET(reiser4_carry_real(node),
+                                               JNODE_ORPHAN)));
+               ON_DEBUG(check_dkeys(reiser4_carry_real(node)));
+               unlock_carry_node(level, node, failure);
+       }
+       level->new_root = NULL;
+}
+
+/* finish with @level
+
+   Unlock nodes and release all allocated resources */
+static void done_carry_level(carry_level * level /* level to finish */ )
+{
+       carry_node *node;
+       carry_node *tmp_node;
+       carry_op *op;
+       carry_op *tmp_op;
+
+       assert("nikita-1076", level != NULL);
+
+       unlock_carry_level(level, 0);
+       for_all_nodes(level, node, tmp_node) {
+               assert("nikita-2113", list_empty_careful(&node->lock_handle.locks_link));
+               assert("nikita-2114", list_empty_careful(&node->lock_handle.owners_link));
+               reiser4_pool_free(&level->pool->node_pool, &node->header);
+       }
+       for_all_ops(level, op, tmp_op)
+           reiser4_pool_free(&level->pool->op_pool, &op->header);
+}
+
+/* helper function to complete locking of carry node
+
+   Finish locking of carry node. There are several ways in which new carry
+   node can be added into carry level and locked. Normal is through
+   lock_carry_node(), but also from find_{left|right}_neighbor(). This
+   function factors out common final part of all locking scenarios. It
+   supposes that @node -> lock_handle is lock handle for lock just taken and
+   fills ->real_node from this lock handle.
+
+*/
+int lock_carry_node_tail(carry_node * node /* node to complete locking of */ )
+{
+       assert("nikita-1052", node != NULL);
+       assert("nikita-1187", reiser4_carry_real(node) != NULL);
+       assert("nikita-1188", !node->unlock);
+
+       node->unlock = 1;
+       /* Load node content into memory and install node plugin by
+          looking at the node header.
+
+          Most of the time this call is cheap because the node is
+          already in memory.
+
+          Corresponding zrelse() is in unlock_carry_node()
+        */
+       return zload(reiser4_carry_real(node));
+}
+
+/* lock carry node
+
+   "Resolve" node to real znode, lock it and mark as locked.
+   This requires recursive locking of znodes.
+
+   When operation is posted to the parent level, node it will be applied to is
+   not yet known. For example, when shifting data between two nodes,
+   delimiting has to be updated in parent or parents of nodes involved. But
+   their parents is not yet locked and, moreover said nodes can be reparented
+   by concurrent balancing.
+
+   To work around this, carry operation is applied to special "carry node"
+   rather than to the znode itself. Carry node consists of some "base" or
+   "reference" znode and flags indicating how to get to the target of carry
+   operation (->real_node field of carry_node) from base.
+
+*/
+int lock_carry_node(carry_level * level /* level @node is in */ ,
+                   carry_node * node /* node to lock */ )
+{
+       int result;
+       znode *reference_point;
+       lock_handle lh;
+       lock_handle tmp_lh;
+       reiser4_tree *tree;
+
+       assert("nikita-887", level != NULL);
+       assert("nikita-882", node != NULL);
+
+       result = 0;
+       reference_point = node->node;
+       init_lh(&lh);
+       init_lh(&tmp_lh);
+       if (node->left_before) {
+               /* handling of new nodes, allocated on the previous level:
+
+                  some carry ops were propably posted from the new node, but
+                  this node neither has parent pointer set, nor is
+                  connected. This will be done in ->create_hook() for
+                  internal item.
+
+                  No then less, parent of new node has to be locked. To do
+                  this, first go to the "left" in the carry order. This
+                  depends on the decision to always allocate new node on the
+                  right of existing one.
+
+                  Loop handles case when multiple nodes, all orphans, were
+                  inserted.
+
+                  Strictly speaking, taking tree lock is not necessary here,
+                  because all nodes scanned by loop in
+                  find_begetting_brother() are write-locked by this thread,
+                  and thus, their sibling linkage cannot change.
+
+                */
+               tree = znode_get_tree(reference_point);
+               read_lock_tree(tree);
+               reference_point = find_begetting_brother(node, level)->node;
+               read_unlock_tree(tree);
+               assert("nikita-1186", reference_point != NULL);
+       }
+       if (node->parent && (result == 0)) {
+               result =
+                   reiser4_get_parent(&tmp_lh, reference_point,
+                                      ZNODE_WRITE_LOCK);
+               if (result != 0) {
+                       ;       /* nothing */
+               } else if (znode_get_level(tmp_lh.node) == 0) {
+                       assert("nikita-1347", znode_above_root(tmp_lh.node));
+                       result = add_new_root(level, node, tmp_lh.node);
+                       if (result == 0) {
+                               reference_point = level->new_root;
+                               move_lh(&lh, &node->lock_handle);
+                       }
+               } else if ((level->new_root != NULL)
+                          && (level->new_root !=
+                              znode_parent_nolock(reference_point))) {
+                       /* parent of node exists, but this level aready
+                          created different new root, so */
+                       warning("nikita-1109",
+                               /* it should be "radicis", but tradition is
+                                  tradition.  do banshees read latin? */
+                               "hodie natus est radici frater");
+                       result = -EIO;
+               } else {
+                       move_lh(&lh, &tmp_lh);
+                       reference_point = lh.node;
+               }
+       }
+       if (node->left && (result == 0)) {
+               assert("nikita-1183", node->parent);
+               assert("nikita-883", reference_point != NULL);
+               result =
+                   reiser4_get_left_neighbor(&tmp_lh, reference_point,
+                                             ZNODE_WRITE_LOCK,
+                                             GN_CAN_USE_UPPER_LEVELS);
+               if (result == 0) {
+                       done_lh(&lh);
+                       move_lh(&lh, &tmp_lh);
+                       reference_point = lh.node;
+               }
+       }
+       if (!node->parent && !node->left && !node->left_before) {
+               result =
+                   longterm_lock_znode(&lh, reference_point, ZNODE_WRITE_LOCK,
+                                       ZNODE_LOCK_HIPRI);
+       }
+       if (result == 0) {
+               move_lh(&node->lock_handle, &lh);
+               result = lock_carry_node_tail(node);
+       }
+       done_lh(&tmp_lh);
+       done_lh(&lh);
+       return result;
+}
+
+/* release a lock on &carry_node.
+
+   Release if necessary lock on @node. This opearion is pair of
+   lock_carry_node() and is idempotent: you can call it more than once on the
+   same node.
+
+*/
+static void
+unlock_carry_node(carry_level * level,
+                 carry_node * node /* node to be released */ ,
+                 int failure   /* 0 if node is unlocked due
+                                * to some error */ )
+{
+       znode *real_node;
+
+       assert("nikita-884", node != NULL);
+
+       real_node = reiser4_carry_real(node);
+       /* pair to zload() in lock_carry_node_tail() */
+       zrelse(real_node);
+       if (node->unlock && (real_node != NULL)) {
+               assert("nikita-899", real_node == node->lock_handle.node);
+               longterm_unlock_znode(&node->lock_handle);
+       }
+       if (failure) {
+               if (node->deallocate && (real_node != NULL)) {
+                       /* free node in bitmap
+
+                          Prepare node for removal. Last zput() will finish
+                          with it.
+                        */
+                       ZF_SET(real_node, JNODE_HEARD_BANSHEE);
+               }
+               if (node->free) {
+                       assert("nikita-2177",
+                              list_empty_careful(&node->lock_handle.locks_link));
+                       assert("nikita-2112",
+                              list_empty_careful(&node->lock_handle.owners_link));
+                       reiser4_pool_free(&level->pool->node_pool,
+                                         &node->header);
+               }
+       }
+}
+
+/* fatal_carry_error() - all-catching error handling function
+
+   It is possible that carry faces unrecoverable error, like unability to
+   insert pointer at the internal level. Our simple solution is just panic in
+   this situation. More sophisticated things like attempt to remount
+   file-system as read-only can be implemented without much difficlties.
+
+   It is believed, that:
+
+   1. in stead of panicking, all current transactions can be aborted rolling
+   system back to the consistent state.
+
+Umm, if you simply panic without doing anything more at all, then all current
+transactions are aborted and the system is rolled back to a consistent state,
+by virtue of the design of the transactional mechanism. Well, wait, let's be
+precise.  If an internal node is corrupted on disk due to hardware failure,
+then there may be no consistent state that can be rolled back to, so instead
+we should say that it will rollback the transactions, which barring other
+factors means rolling back to a consistent state.
+
+# Nikita: there is a subtle difference between panic and aborting
+# transactions: machine doesn't reboot. Processes aren't killed. Processes
+# don't using reiser4 (not that we care about such processes), or using other
+# reiser4 mounts (about them we do care) will simply continue to run. With
+# some luck, even application using aborted file system can survive: it will
+# get some error, like EBADF, from each file descriptor on failed file system,
+# but applications that do care about tolerance will cope with this (squid
+# will).
+
+It would be a nice feature though to support rollback without rebooting
+followed by remount, but this can wait for later versions.
+
+   2. once isolated transactions will be implemented it will be possible to
+   roll back offending transaction.
+
+2. is additional code complexity of inconsistent value (it implies that a broken tree should be kept in operation), so we must think about
+it more before deciding if it should be done.  -Hans
+
+*/
+static void fatal_carry_error(carry_level * doing UNUSED_ARG   /* carry level
+                                                                * where
+                                                                * unrecoverable
+                                                                * error
+                                                                * occurred */ ,
+                             int ecode /* error code */ )
+{
+       assert("nikita-1230", doing != NULL);
+       assert("nikita-1231", ecode < 0);
+
+       reiser4_panic("nikita-1232", "Carry failed: %i", ecode);
+}
+
+/* add new root to the tree
+
+   This function itself only manages changes in carry structures and delegates
+   all hard work (allocation of znode for new root, changes of parent and
+   sibling pointers to the reiser4_add_tree_root().
+
+   Locking: old tree root is locked by carry at this point. Fake znode is also
+   locked.
+
+*/
+static int add_new_root(carry_level * level    /* carry level in context of which
+                                                * operation is performed */ ,
+                       carry_node * node /* carry node for existing root */ ,
+                       znode * fake    /* "fake" znode already locked by
+                                        * us */ )
+{
+       int result;
+
+       assert("nikita-1104", level != NULL);
+       assert("nikita-1105", node != NULL);
+
+       assert("nikita-1403", znode_is_write_locked(node->node));
+       assert("nikita-1404", znode_is_write_locked(fake));
+
+       /* trying to create new root. */
+       /* @node is root and it's already locked by us. This
+          means that nobody else can be trying to add/remove
+          tree root right now.
+        */
+       if (level->new_root == NULL)
+               level->new_root = reiser4_add_tree_root(node->node, fake);
+       if (!IS_ERR(level->new_root)) {
+               assert("nikita-1210", znode_is_root(level->new_root));
+               node->deallocate = 1;
+               result =
+                   longterm_lock_znode(&node->lock_handle, level->new_root,
+                                       ZNODE_WRITE_LOCK, ZNODE_LOCK_LOPRI);
+               if (result == 0)
+                       zput(level->new_root);
+       } else {
+               result = PTR_ERR(level->new_root);
+               level->new_root = NULL;
+       }
+       return result;
+}
+
+/* allocate new znode and add the operation that inserts the
+   pointer to it into the parent node into the todo level
+
+   Allocate new znode, add it into carry queue and post into @todo queue
+   request to add pointer to new node into its parent.
+
+   This is carry related routing that calls reiser4_new_node() to allocate new
+   node.
+*/
+carry_node *add_new_znode(znode * brother      /* existing left neighbor of new
+                                                * node */ ,
+                         carry_node * ref      /* carry node after which new
+                                                * carry node is to be inserted
+                                                * into queue. This affects
+                                                * locking. */ ,
+                         carry_level * doing   /* carry queue where new node is
+                                                * to be added */ ,
+                         carry_level * todo    /* carry queue where COP_INSERT
+                                                * operation to add pointer to
+                                                * new node will ne added */ )
+{
+       carry_node *fresh;
+       znode *new_znode;
+       carry_op *add_pointer;
+       carry_plugin_info info;
+
+       assert("nikita-1048", brother != NULL);
+       assert("nikita-1049", todo != NULL);
+
+       /* There is a lot of possible variations here: to what parent
+          new node will be attached and where. For simplicity, always
+          do the following:
+
+          (1) new node and @brother will have the same parent.
+
+          (2) new node is added on the right of @brother
+
+        */
+
+       fresh = reiser4_add_carry_skip(doing,
+                                      ref ? POOLO_AFTER : POOLO_LAST, ref);
+       if (IS_ERR(fresh))
+               return fresh;
+
+       fresh->deallocate = 1;
+       fresh->free = 1;
+
+       new_znode = reiser4_new_node(brother, znode_get_level(brother));
+       if (IS_ERR(new_znode))
+               /* @fresh will be deallocated automatically by error
+                  handling code in the caller. */
+               return (carry_node *) new_znode;
+
+       /* new_znode returned znode with x_count 1. Caller has to decrease
+          it. make_space() does. */
+
+       ZF_SET(new_znode, JNODE_ORPHAN);
+       fresh->node = new_znode;
+
+       while (ZF_ISSET(reiser4_carry_real(ref), JNODE_ORPHAN)) {
+               ref = carry_node_prev(ref);
+               assert("nikita-1606", !carry_node_end(doing, ref));
+       }
+
+       info.todo = todo;
+       info.doing = doing;
+       add_pointer = node_post_carry(&info, COP_INSERT,
+                                     reiser4_carry_real(ref), 1);
+       if (IS_ERR(add_pointer)) {
+               /* no need to deallocate @new_znode here: it will be
+                  deallocated during carry error handling. */
+               return (carry_node *) add_pointer;
+       }
+
+       add_pointer->u.insert.type = COPT_CHILD;
+       add_pointer->u.insert.child = fresh;
+       add_pointer->u.insert.brother = brother;
+       /* initially new node spawns empty key range */
+       write_lock_dk(znode_get_tree(brother));
+       znode_set_ld_key(new_znode,
+                        znode_set_rd_key(new_znode,
+                                         znode_get_rd_key(brother)));
+       write_unlock_dk(znode_get_tree(brother));
+       return fresh;
+}
+
+/* DEBUGGING FUNCTIONS.
+
+   Probably we also should leave them on even when
+   debugging is turned off to print dumps at errors.
+*/
+#if REISER4_DEBUG
+static int carry_level_invariant(carry_level * level, carry_queue_state state)
+{
+       carry_node *node;
+       carry_node *tmp_node;
+
+       if (level == NULL)
+               return 0;
+
+       if (level->track_type != 0 &&
+           level->track_type != CARRY_TRACK_NODE &&
+           level->track_type != CARRY_TRACK_CHANGE)
+               return 0;
+
+       /* check that nodes are in ascending order */
+       for_all_nodes(level, node, tmp_node) {
+               znode *left;
+               znode *right;
+
+               reiser4_key lkey;
+               reiser4_key rkey;
+
+               if (node != carry_node_front(level)) {
+                       if (state == CARRY_TODO) {
+                               right = node->node;
+                               left = carry_node_prev(node)->node;
+                       } else {
+                               right = reiser4_carry_real(node);
+                               left = reiser4_carry_real(carry_node_prev(node));
+                       }
+                       if (right == NULL || left == NULL)
+                               continue;
+                       if (node_is_empty(right) || node_is_empty(left))
+                               continue;
+                       if (!keyle(leftmost_key_in_node(left, &lkey),
+                                  leftmost_key_in_node(right, &rkey))) {
+                               warning("", "wrong key order");
+                               return 0;
+                       }
+               }
+       }
+       return 1;
+}
+#endif
+
+/* get symbolic name for boolean */
+static const char *tf(int boolean /* truth value */ )
+{
+       return boolean ? "t" : "f";
+}
+
+/* symbolic name for carry operation */
+static const char *carry_op_name(carry_opcode op /* carry opcode */ )
+{
+       switch (op) {
+       case COP_INSERT:
+               return "COP_INSERT";
+       case COP_DELETE:
+               return "COP_DELETE";
+       case COP_CUT:
+               return "COP_CUT";
+       case COP_PASTE:
+               return "COP_PASTE";
+       case COP_UPDATE:
+               return "COP_UPDATE";
+       case COP_EXTENT:
+               return "COP_EXTENT";
+       case COP_INSERT_FLOW:
+               return "COP_INSERT_FLOW";
+       default:{
+                       /* not mt safe, but who cares? */
+                       static char buf[20];
+
+                       sprintf(buf, "unknown op: %x", op);
+                       return buf;
+               }
+       }
+}
+
+/* dump information about carry node */
+static void print_carry(const char *prefix /* prefix to print */ ,
+                       carry_node * node /* node to print */ )
+{
+       if (node == NULL) {
+               printk("%s: null\n", prefix);
+               return;
+       }
+       printk
+           ("%s: %p parent: %s, left: %s, unlock: %s, free: %s, dealloc: %s\n",
+            prefix, node, tf(node->parent), tf(node->left), tf(node->unlock),
+            tf(node->free), tf(node->deallocate));
+}
+
+/* dump information about carry operation */
+static void print_op(const char *prefix /* prefix to print */ ,
+                    carry_op * op /* operation to print */ )
+{
+       if (op == NULL) {
+               printk("%s: null\n", prefix);
+               return;
+       }
+       printk("%s: %p carry_opcode: %s\n", prefix, op, carry_op_name(op->op));
+       print_carry("\tnode", op->node);
+       switch (op->op) {
+       case COP_INSERT:
+       case COP_PASTE:
+               print_coord("\tcoord",
+                           op->u.insert.d ? op->u.insert.d->coord : NULL, 0);
+               reiser4_print_key("\tkey",
+                                 op->u.insert.d ? op->u.insert.d->key : NULL);
+               print_carry("\tchild", op->u.insert.child);
+               break;
+       case COP_DELETE:
+               print_carry("\tchild", op->u.delete.child);
+               break;
+       case COP_CUT:
+               if (op->u.cut_or_kill.is_cut) {
+                       print_coord("\tfrom",
+                                   op->u.cut_or_kill.u.kill->params.from, 0);
+                       print_coord("\tto", op->u.cut_or_kill.u.kill->params.to,
+                                   0);
+               } else {
+                       print_coord("\tfrom",
+                                   op->u.cut_or_kill.u.cut->params.from, 0);
+                       print_coord("\tto", op->u.cut_or_kill.u.cut->params.to,
+                                   0);
+               }
+               break;
+       case COP_UPDATE:
+               print_carry("\tleft", op->u.update.left);
+               break;
+       default:
+               /* do nothing */
+               break;
+       }
+}
+
+/* dump information about all nodes and operations in a @level */
+static void print_level(const char *prefix /* prefix to print */ ,
+                       carry_level * level /* level to print */ )
+{
+       carry_node *node;
+       carry_node *tmp_node;
+       carry_op *op;
+       carry_op *tmp_op;
+
+       if (level == NULL) {
+               printk("%s: null\n", prefix);
+               return;
+       }
+       printk("%s: %p, restartable: %s\n",
+              prefix, level, tf(level->restartable));
+
+       for_all_nodes(level, node, tmp_node)
+           print_carry("\tcarry node", node);
+       for_all_ops(level, op, tmp_op)
+           print_op("\tcarry op", op);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/carry.h linux-2.6.20/fs/reiser4/carry.h
--- linux-2.6.20.orig/fs/reiser4/carry.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/carry.h     2007-05-06 14:50:43.690973225 +0400
@@ -0,0 +1,442 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Functions and data types to "carry" tree modification(s) upward.
+   See fs/reiser4/carry.c for details. */
+
+#if !defined( __FS_REISER4_CARRY_H__ )
+#define __FS_REISER4_CARRY_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "pool.h"
+#include "znode.h"
+
+#include <linux/types.h>
+
+/* &carry_node - "location" of carry node.
+
+   "location" of node that is involved or going to be involved into
+   carry process. Node where operation will be carried to on the
+   parent level cannot be recorded explicitly. Operation will be carried
+   usually to the parent of some node (where changes are performed at
+   the current level) or, to the left neighbor of its parent. But while
+   modifications are performed at the current level, parent may
+   change. So, we have to allow some indirection (or, positevly,
+   flexibility) in locating carry nodes.
+
+*/
+typedef struct carry_node {
+       /* pool linkage */
+       reiser4_pool_header header;
+
+       /* base node from which real_node is calculated. See
+          fs/reiser4/carry.c:lock_carry_node(). */
+       znode *node;
+
+       /* how to get ->real_node */
+       /* to get ->real_node obtain parent of ->node */
+       __u32 parent:1;
+       /* to get ->real_node obtain left neighbor of parent of
+          ->node */
+       __u32 left:1;
+       __u32 left_before:1;
+
+       /* locking */
+
+       /* this node was locked by carry process and should be
+          unlocked when carry leaves a level */
+       __u32 unlock:1;
+
+       /* disk block for this node was allocated by carry process and
+          should be deallocated when carry leaves a level */
+       __u32 deallocate:1;
+       /* this carry node was allocated by carry process and should be
+          freed when carry leaves a level */
+       __u32 free:1;
+
+       /* type of lock we want to take on this node */
+       lock_handle lock_handle;
+} carry_node;
+
+/* &carry_opcode - elementary operations that can be carried upward
+
+   Operations that carry() can handle. This list is supposed to be
+   expanded.
+
+   Each carry operation (cop) is handled by appropriate function defined
+   in fs/reiser4/carry.c. For example COP_INSERT is handled by
+   fs/reiser4/carry.c:carry_insert() etc. These functions in turn
+   call plugins of nodes affected by operation to modify nodes' content
+   and to gather operations to be performed on the next level.
+
+*/
+typedef enum {
+       /* insert new item into node. */
+       COP_INSERT,
+       /* delete pointer from parent node */
+       COP_DELETE,
+       /* remove part of or whole node. */
+       COP_CUT,
+       /* increase size of item. */
+       COP_PASTE,
+       /* insert extent (that is sequence of unformatted nodes). */
+       COP_EXTENT,
+       /* update delimiting key in least common ancestor of two
+          nodes. This is performed when items are moved between two
+          nodes.
+        */
+       COP_UPDATE,
+       /* insert flow */
+       COP_INSERT_FLOW,
+       COP_LAST_OP,
+} carry_opcode;
+
+#define CARRY_FLOW_NEW_NODES_LIMIT 20
+
+/* mode (or subtype) of COP_{INSERT|PASTE} operation. Specifies how target
+   item is determined. */
+typedef enum {
+       /* target item is one containing pointer to the ->child node */
+       COPT_CHILD,
+       /* target item is given explicitly by @coord */
+       COPT_ITEM_DATA,
+       /* target item is given by key */
+       COPT_KEY,
+       /* see insert_paste_common() for more comments on this. */
+       COPT_PASTE_RESTARTED,
+} cop_insert_pos_type;
+
+/* flags to cut and delete */
+typedef enum {
+       /* don't kill node even if it became completely empty as results of
+        * cut. This is needed for eottl handling. See carry_extent() for
+        * details. */
+       DELETE_RETAIN_EMPTY = (1 << 0)
+} cop_delete_flag;
+
+/*
+ * carry() implements "lock handle tracking" feature.
+ *
+ * Callers supply carry with node where to perform initial operation and lock
+ * handle on this node. Trying to optimize node utilization carry may actually
+ * move insertion point to different node. Callers expect that lock handle
+ * will rebe transferred to the new node also.
+ *
+ */
+typedef enum {
+       /* transfer lock handle along with insertion point */
+       CARRY_TRACK_CHANGE = 1,
+       /* acquire new lock handle to the node where insertion point is. This
+        * is used when carry() client doesn't initially possess lock handle
+        * on the insertion point node, for example, by extent insertion
+        * code. See carry_extent(). */
+       CARRY_TRACK_NODE = 2
+} carry_track_type;
+
+/* data supplied to COP_{INSERT|PASTE} by callers */
+typedef struct carry_insert_data {
+       /* position where new item is to be inserted */
+       coord_t *coord;
+       /* new item description */
+       reiser4_item_data *data;
+       /* key of new item */
+       const reiser4_key *key;
+} carry_insert_data;
+
+/* cut and kill are similar, so carry_cut_data and carry_kill_data share the below structure of parameters */
+struct cut_kill_params {
+       /* coord where cut starts (inclusive) */
+       coord_t *from;
+       /* coord where cut stops (inclusive, this item/unit will also be
+        * cut) */
+       coord_t *to;
+       /* starting key. This is necessary when item and unit pos don't
+        * uniquely identify what portion or tree to remove. For example, this
+        * indicates what portion of extent unit will be affected. */
+       const reiser4_key *from_key;
+       /* exclusive stop key */
+       const reiser4_key *to_key;
+       /* if this is not NULL, smallest actually removed key is stored
+        * here. */
+       reiser4_key *smallest_removed;
+       /* kill_node_content()  is called for file truncate */
+       int truncate;
+};
+
+struct carry_cut_data {
+       struct cut_kill_params params;
+};
+
+struct carry_kill_data {
+       struct cut_kill_params params;
+       /* parameter to be passed to the ->kill_hook() method of item
+        * plugin */
+       /*void *iplug_params; *//* FIXME: unused currently */
+       /* if not NULL---inode whose items are being removed. This is needed
+        * for ->kill_hook() of extent item to update VM structures when
+        * removing pages. */
+       struct inode *inode;
+       /* sibling list maintenance is complicated by existence of eottl. When
+        * eottl whose left and right neighbors are formatted leaves is
+        * removed, one has to connect said leaves in the sibling list. This
+        * cannot be done when extent removal is just started as locking rules
+        * require sibling list update to happen atomically with removal of
+        * extent item. Therefore: 1. pointers to left and right neighbors
+        * have to be passed down to the ->kill_hook() of extent item, and
+        * 2. said neighbors have to be locked. */
+       lock_handle *left;
+       lock_handle *right;
+       /* flags modifying behavior of kill. Currently, it may have DELETE_RETAIN_EMPTY set. */
+       unsigned flags;
+       char *buf;
+};
+
+/* &carry_tree_op - operation to "carry" upward.
+
+   Description of an operation we want to "carry" to the upper level of
+   a tree: e.g, when we insert something and there is not enough space
+   we allocate a new node and "carry" the operation of inserting a
+   pointer to the new node to the upper level, on removal of empty node,
+   we carry up operation of removing appropriate entry from parent.
+
+   There are two types of carry ops: when adding or deleting node we
+   node at the parent level where appropriate modification has to be
+   performed is known in advance. When shifting items between nodes
+   (split, merge), delimiting key should be changed in the least common
+   parent of the nodes involved that is not known in advance.
+
+   For the operations of the first type we store in &carry_op pointer to
+   the &carry_node at the parent level. For the operation of the second
+   type we store &carry_node or parents of the left and right nodes
+   modified and keep track of them upward until they coincide.
+
+*/
+typedef struct carry_op {
+       /* pool linkage */
+       reiser4_pool_header header;
+       carry_opcode op;
+       /* node on which operation is to be performed:
+
+          for insert, paste: node where new item is to be inserted
+
+          for delete: node where pointer is to be deleted
+
+          for cut: node to cut from
+
+          for update: node where delimiting key is to be modified
+
+          for modify: parent of modified node
+
+        */
+       carry_node *node;
+       union {
+               struct {
+                       /* (sub-)type of insertion/paste. Taken from
+                          cop_insert_pos_type. */
+                       __u8 type;
+                       /* various operation flags. Taken from
+                          cop_insert_flag. */
+                       __u8 flags;
+                       carry_insert_data *d;
+                       carry_node *child;
+                       znode *brother;
+               } insert, paste, extent;
+
+               struct {
+                       int is_cut;
+                       union {
+                               carry_kill_data *kill;
+                               carry_cut_data *cut;
+                       } u;
+               } cut_or_kill;
+
+               struct {
+                       carry_node *left;
+               } update;
+               struct {
+                       /* changed child */
+                       carry_node *child;
+                       /* bitmask of changes. See &cop_modify_flag */
+                       __u32 flag;
+               } modify;
+               struct {
+                       /* flags to deletion operation. Are taken from
+                          cop_delete_flag */
+                       __u32 flags;
+                       /* child to delete from parent. If this is
+                          NULL, delete op->node.  */
+                       carry_node *child;
+               } delete;
+               struct {
+                       /* various operation flags. Taken from
+                          cop_insert_flag. */
+                       __u32 flags;
+                       flow_t *flow;
+                       coord_t *insert_point;
+                       reiser4_item_data *data;
+                       /* flow insertion is limited by number of new blocks
+                          added in that operation which do not get any data
+                          but part of flow. This limit is set by macro
+                          CARRY_FLOW_NEW_NODES_LIMIT. This field stores number
+                          of nodes added already during one carry_flow */
+                       int new_nodes;
+               } insert_flow;
+       } u;
+} carry_op;
+
+/* &carry_op_pool - preallocated pool of carry operations, and nodes */
+typedef struct carry_pool {
+       carry_op op[CARRIES_POOL_SIZE];
+       reiser4_pool op_pool;
+       carry_node node[NODES_LOCKED_POOL_SIZE];
+       reiser4_pool node_pool;
+} carry_pool;
+
+/* &carry_tree_level - carry process on given level
+
+   Description of balancing process on the given level.
+
+   No need for locking here, as carry_tree_level is essentially per
+   thread thing (for now).
+
+*/
+struct carry_level {
+       /* this level may be restarted */
+       __u32 restartable:1;
+       /* list of carry nodes on this level, ordered by key order */
+       struct list_head nodes;
+       struct list_head ops;
+       /* pool where new objects are allocated from */
+       carry_pool *pool;
+       int ops_num;
+       int nodes_num;
+       /* new root created on this level, if any */
+       znode *new_root;
+       /* This is set by caller (insert_by_key(), rreiser4_esize_item(), etc.)
+          when they want ->tracked to automagically wander to the node where
+          insertion point moved after insert or paste.
+        */
+       carry_track_type track_type;
+       /* lock handle supplied by user that we are tracking. See
+          above. */
+       lock_handle *tracked;
+};
+
+/* information carry passes to plugin methods that may add new operations to
+   the @todo queue  */
+struct carry_plugin_info {
+       carry_level *doing;
+       carry_level *todo;
+};
+
+int reiser4_carry(carry_level * doing, carry_level * done);
+
+carry_node *reiser4_add_carry(carry_level * level, pool_ordering order,
+                             carry_node * reference);
+carry_node *reiser4_add_carry_skip(carry_level * level, pool_ordering order,
+                                  carry_node * reference);
+
+extern carry_node *insert_carry_node(carry_level * doing,
+                                    carry_level * todo, const znode * node);
+
+extern carry_pool *init_carry_pool(int);
+extern void done_carry_pool(carry_pool * pool);
+
+extern void init_carry_level(carry_level * level, carry_pool * pool);
+
+extern carry_op *reiser4_post_carry(carry_level * level, carry_opcode op,
+                                   znode * node, int apply_to_parent);
+extern carry_op *node_post_carry(carry_plugin_info * info, carry_opcode op,
+                                znode * node, int apply_to_parent_p);
+
+carry_node *add_new_znode(znode * brother, carry_node * reference,
+                         carry_level * doing, carry_level * todo);
+
+carry_node *find_carry_node(carry_level * level, const znode * node);
+
+extern znode *reiser4_carry_real(const carry_node * node);
+
+/* helper macros to iterate over carry queues */
+
+#define carry_node_next( node )                                        \
+       list_entry((node)->header.level_linkage.next, carry_node,       \
+                  header.level_linkage)
+
+#define carry_node_prev( node )                                        \
+       list_entry((node)->header.level_linkage.prev, carry_node,       \
+                  header.level_linkage)
+
+#define carry_node_front( level )                                              \
+       list_entry((level)->nodes.next, carry_node, header.level_linkage)
+
+#define carry_node_back( level )                                               \
+       list_entry((level)->nodes.prev, carry_node, header.level_linkage)
+
+#define carry_node_end( level, node )                          \
+       (&(level)->nodes == &(node)->header.level_linkage)
+
+/* macro to iterate over all operations in a @level */
+#define for_all_ops( level /* carry level (of type carry_level *) */,                  \
+                    op    /* pointer to carry operation, modified by loop (of          \
+                           * type carry_op *) */,                                      \
+                    tmp   /* pointer to carry operation (of type carry_op *),          \
+                           * used to make iterator stable in the face of               \
+                           * deletions from the level */ )                             \
+for (op = list_entry(level->ops.next, carry_op, header.level_linkage),                 \
+     tmp = list_entry(op->header.level_linkage.next, carry_op, header.level_linkage);  \
+     &op->header.level_linkage != &level->ops;                                         \
+     op = tmp,                                                                         \
+     tmp = list_entry(op->header.level_linkage.next, carry_op, header.level_linkage))
+
+#if 0
+for( op = ( carry_op * ) pool_level_list_front( &level -> ops ),               \
+     tmp = ( carry_op * ) pool_level_list_next( &op -> header ) ;              \
+     ! pool_level_list_end( &level -> ops, &op -> header ) ;                   \
+     op = tmp, tmp = ( carry_op * ) pool_level_list_next( &op -> header ) )
+#endif
+
+/* macro to iterate over all nodes in a @level */                                              \
+#define for_all_nodes( level /* carry level (of type carry_level *) */,                                \
+                      node  /* pointer to carry node, modified by loop (of                     \
+                             * type carry_node *) */,                                          \
+                      tmp   /* pointer to carry node (of type carry_node *),                   \
+                             * used to make iterator stable in the face of *                   \
+                             * deletions from the level */ )                                   \
+for (node = list_entry(level->nodes.next, carry_node, header.level_linkage),                   \
+     tmp = list_entry(node->header.level_linkage.next, carry_node, header.level_linkage);      \
+     &node->header.level_linkage != &level->nodes;                                             \
+     node = tmp,                                                                               \
+     tmp = list_entry(node->header.level_linkage.next, carry_node, header.level_linkage))
+
+#if 0
+for( node = carry_node_front( level ),                                         \
+     tmp = carry_node_next( node ) ; ! carry_node_end( level, node ) ;         \
+     node = tmp, tmp = carry_node_next( node ) )
+#endif
+
+/* macro to iterate over all nodes in a @level in reverse order
+
+   This is used, because nodes are unlocked in reversed order of locking */
+#define for_all_nodes_back( level /* carry level (of type carry_level *) */,   \
+                           node  /* pointer to carry node, modified by loop    \
+                                  * (of type carry_node *) */,                 \
+                           tmp   /* pointer to carry node (of type carry_node  \
+                                  * *), used to make iterator stable in the    \
+                                  * face of deletions from the level */ )      \
+for( node = carry_node_back( level ),          \
+     tmp = carry_node_prev( node ) ; ! carry_node_end( level, node ) ;         \
+     node = tmp, tmp = carry_node_prev( node ) )
+
+/* __FS_REISER4_CARRY_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/carry_ops.c linux-2.6.20/fs/reiser4/carry_ops.c
--- linux-2.6.20.orig/fs/reiser4/carry_ops.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/carry_ops.c 2007-05-06 14:50:43.694974475 +0400
@@ -0,0 +1,2131 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* implementation of carry operations */
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/node/node.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "pool.h"
+#include "tree_mod.h"
+#include "carry.h"
+#include "carry_ops.h"
+#include "tree.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/types.h>
+#include <linux/err.h>
+
+static int carry_shift_data(sideof side, coord_t * insert_coord, znode * node,
+                           carry_level * doing, carry_level * todo,
+                           unsigned int including_insert_coord_p);
+
+extern int lock_carry_node(carry_level * level, carry_node * node);
+extern int lock_carry_node_tail(carry_node * node);
+
+/* find left neighbor of a carry node
+
+   Look for left neighbor of @node and add it to the @doing queue. See
+   comments in the body.
+
+*/
+static carry_node *find_left_neighbor(carry_op * op    /* node to find left
+                                                        * neighbor of */ ,
+                                     carry_level * doing /* level to scan */ )
+{
+       int result;
+       carry_node *node;
+       carry_node *left;
+       int flags;
+       reiser4_tree *tree;
+
+       node = op->node;
+
+       tree = current_tree;
+       read_lock_tree(tree);
+       /* first, check whether left neighbor is already in a @doing queue */
+       if (reiser4_carry_real(node)->left != NULL) {
+               /* NOTE: there is locking subtlety here. Look into
+                * find_right_neighbor() for more info */
+               if (find_carry_node(doing,
+                                   reiser4_carry_real(node)->left) != NULL) {
+                       read_unlock_tree(tree);
+                       left = node;
+                       do {
+                               left = list_entry(left->header.level_linkage.prev,
+                                                 carry_node, header.level_linkage);
+                               assert("nikita-3408", !carry_node_end(doing,
+                                                                     left));
+                       } while (reiser4_carry_real(left) ==
+                                reiser4_carry_real(node));
+                       return left;
+               }
+       }
+       read_unlock_tree(tree);
+
+       left = reiser4_add_carry_skip(doing, POOLO_BEFORE, node);
+       if (IS_ERR(left))
+               return left;
+
+       left->node = node->node;
+       left->free = 1;
+
+       flags = GN_TRY_LOCK;
+       if (!op->u.insert.flags & COPI_LOAD_LEFT)
+               flags |= GN_NO_ALLOC;
+
+       /* then, feeling lucky, peek left neighbor in the cache. */
+       result = reiser4_get_left_neighbor(&left->lock_handle,
+                                          reiser4_carry_real(node),
+                                          ZNODE_WRITE_LOCK, flags);
+       if (result == 0) {
+               /* ok, node found and locked. */
+               result = lock_carry_node_tail(left);
+               if (result != 0)
+                       left = ERR_PTR(result);
+       } else if (result == -E_NO_NEIGHBOR || result == -ENOENT) {
+               /* node is leftmost node in a tree, or neighbor wasn't in
+                  cache, or there is an extent on the left. */
+               reiser4_pool_free(&doing->pool->node_pool, &left->header);
+               left = NULL;
+       } else if (doing->restartable) {
+               /* if left neighbor is locked, and level is restartable, add
+                  new node to @doing and restart. */
+               assert("nikita-913", node->parent != 0);
+               assert("nikita-914", node->node != NULL);
+               left->left = 1;
+               left->free = 0;
+               left = ERR_PTR(-E_REPEAT);
+       } else {
+               /* left neighbor is locked, level cannot be restarted. Just
+                  ignore left neighbor. */
+               reiser4_pool_free(&doing->pool->node_pool, &left->header);
+               left = NULL;
+       }
+       return left;
+}
+
+/* find right neighbor of a carry node
+
+   Look for right neighbor of @node and add it to the @doing queue. See
+   comments in the body.
+
+*/
+static carry_node *find_right_neighbor(carry_op * op   /* node to find right
+                                                        * neighbor of */ ,
+                                      carry_level * doing /* level to scan */ )
+{
+       int result;
+       carry_node *node;
+       carry_node *right;
+       lock_handle lh;
+       int flags;
+       reiser4_tree *tree;
+
+       init_lh(&lh);
+
+       node = op->node;
+
+       tree = current_tree;
+       read_lock_tree(tree);
+       /* first, check whether right neighbor is already in a @doing queue */
+       if (reiser4_carry_real(node)->right != NULL) {
+               /*
+                * Tree lock is taken here anyway, because, even if _outcome_
+                * of (find_carry_node() != NULL) doesn't depends on
+                * concurrent updates to ->right, find_carry_node() cannot
+                * work with second argument NULL. Hence, following comment is
+                * of historic importance only.
+                *
+                * Subtle:
+                *
+                * Q: why don't we need tree lock here, looking for the right
+                * neighbor?
+                *
+                * A: even if value of node->real_node->right were changed
+                * during find_carry_node() execution, outcome of execution
+                * wouldn't change, because (in short) other thread cannot add
+                * elements to the @doing, and if node->real_node->right
+                * already was in @doing, value of node->real_node->right
+                * couldn't change, because node cannot be inserted between
+                * locked neighbors.
+                */
+               if (find_carry_node(doing,
+                                   reiser4_carry_real(node)->right) != NULL) {
+                       read_unlock_tree(tree);
+                       /*
+                        * What we are doing here (this is also applicable to
+                        * the find_left_neighbor()).
+                        *
+                        * tree_walk.c code requires that insertion of a
+                        * pointer to a child, modification of parent pointer
+                        * in the child, and insertion of the child into
+                        * sibling list are atomic (see
+                        * plugin/item/internal.c:create_hook_internal()).
+                        *
+                        * carry allocates new node long before pointer to it
+                        * is inserted into parent and, actually, long before
+                        * parent is even known. Such allocated-but-orphaned
+                        * nodes are only trackable through carry level lists.
+                        *
+                        * Situation that is handled here is following: @node
+                        * has valid ->right pointer, but there is
+                        * allocated-but-orphaned node in the carry queue that
+                        * is logically between @node and @node->right. Here
+                        * we are searching for it. Critical point is that
+                        * this is only possible if @node->right is also in
+                        * the carry queue (this is checked above), because
+                        * this is the only way new orphaned node could be
+                        * inserted between them (before inserting new node,
+                        * make_space() first tries to shift to the right, so,
+                        * right neighbor will be locked and queued).
+                        *
+                        */
+                       right = node;
+                       do {
+                               right = list_entry(right->header.level_linkage.next,
+                                                  carry_node, header.level_linkage);
+                               assert("nikita-3408", !carry_node_end(doing,
+                                                                     right));
+                       } while (reiser4_carry_real(right) ==
+                                reiser4_carry_real(node));
+                       return right;
+               }
+       }
+       read_unlock_tree(tree);
+
+       flags = GN_CAN_USE_UPPER_LEVELS;
+       if (!op->u.insert.flags & COPI_LOAD_RIGHT)
+               flags = GN_NO_ALLOC;
+
+       /* then, try to lock right neighbor */
+       init_lh(&lh);
+       result = reiser4_get_right_neighbor(&lh,
+                                           reiser4_carry_real(node),
+                                           ZNODE_WRITE_LOCK, flags);
+       if (result == 0) {
+               /* ok, node found and locked. */
+               right = reiser4_add_carry_skip(doing, POOLO_AFTER, node);
+               if (!IS_ERR(right)) {
+                       right->node = lh.node;
+                       move_lh(&right->lock_handle, &lh);
+                       right->free = 1;
+                       result = lock_carry_node_tail(right);
+                       if (result != 0)
+                               right = ERR_PTR(result);
+               }
+       } else if ((result == -E_NO_NEIGHBOR) || (result == -ENOENT)) {
+               /* node is rightmost node in a tree, or neighbor wasn't in
+                  cache, or there is an extent on the right. */
+               right = NULL;
+       } else
+               right = ERR_PTR(result);
+       done_lh(&lh);
+       return right;
+}
+
+/* how much free space in a @node is needed for @op
+
+   How much space in @node is required for completion of @op, where @op is
+   insert or paste operation.
+*/
+static unsigned int space_needed_for_op(znode * node   /* znode data are
+                                                        * inserted or
+                                                        * pasted in */ ,
+                                       carry_op * op   /* carry
+                                                          operation */ )
+{
+       assert("nikita-919", op != NULL);
+
+       switch (op->op) {
+       default:
+               impossible("nikita-1701", "Wrong opcode");
+       case COP_INSERT:
+               return space_needed(node, NULL, op->u.insert.d->data, 1);
+       case COP_PASTE:
+               return space_needed(node, op->u.insert.d->coord,
+                                   op->u.insert.d->data, 0);
+       }
+}
+
+/* how much space in @node is required to insert or paste @data at
+   @coord. */
+unsigned int space_needed(const znode * node   /* node data are inserted or
+                                                * pasted in */ ,
+                         const coord_t * coord /* coord where data are
+                                                * inserted or pasted
+                                                * at */ ,
+                         const reiser4_item_data * data        /* data to insert or
+                                                                * paste */ ,
+                         int insertion /* non-0 is inserting, 0---paste */ )
+{
+       int result;
+       item_plugin *iplug;
+
+       assert("nikita-917", node != NULL);
+       assert("nikita-918", node_plugin_by_node(node) != NULL);
+       assert("vs-230", !insertion || (coord == NULL));
+
+       result = 0;
+       iplug = data->iplug;
+       if (iplug->b.estimate != NULL) {
+               /* ask item plugin how much space is needed to insert this
+                  item */
+               result += iplug->b.estimate(insertion ? NULL : coord, data);
+       } else {
+               /* reasonable default */
+               result += data->length;
+       }
+       if (insertion) {
+               node_plugin *nplug;
+
+               nplug = node->nplug;
+               /* and add node overhead */
+               if (nplug->item_overhead != NULL) {
+                       result += nplug->item_overhead(node, NULL);
+               }
+       }
+       return result;
+}
+
+/* find &coord in parent where pointer to new child is to be stored. */
+static int find_new_child_coord(carry_op * op  /* COP_INSERT carry operation to
+                                                * insert pointer to new
+                                                * child */ )
+{
+       int result;
+       znode *node;
+       znode *child;
+
+       assert("nikita-941", op != NULL);
+       assert("nikita-942", op->op == COP_INSERT);
+
+       node = reiser4_carry_real(op->node);
+       assert("nikita-943", node != NULL);
+       assert("nikita-944", node_plugin_by_node(node) != NULL);
+
+       child = reiser4_carry_real(op->u.insert.child);
+       result =
+           find_new_child_ptr(node, child, op->u.insert.brother,
+                              op->u.insert.d->coord);
+
+       build_child_ptr_data(child, op->u.insert.d->data);
+       return result;
+}
+
+/* additional amount of free space in @node required to complete @op */
+static int free_space_shortage(znode * node /* node to check */ ,
+                              carry_op * op /* operation being performed */ )
+{
+       assert("nikita-1061", node != NULL);
+       assert("nikita-1062", op != NULL);
+
+       switch (op->op) {
+       default:
+               impossible("nikita-1702", "Wrong opcode");
+       case COP_INSERT:
+       case COP_PASTE:
+               return space_needed_for_op(node, op) - znode_free_space(node);
+       case COP_EXTENT:
+               /* when inserting extent shift data around until insertion
+                  point is utmost in the node. */
+               if (coord_wrt(op->u.insert.d->coord) == COORD_INSIDE)
+                       return +1;
+               else
+                       return -1;
+       }
+}
+
+/* helper function: update node pointer in operation after insertion
+   point was probably shifted into @target. */
+static znode *sync_op(carry_op * op, carry_node * target)
+{
+       znode *insertion_node;
+
+       /* reget node from coord: shift might move insertion coord to
+          the neighbor */
+       insertion_node = op->u.insert.d->coord->node;
+       /* if insertion point was actually moved into new node,
+          update carry node pointer in operation. */
+       if (insertion_node != reiser4_carry_real(op->node)) {
+               op->node = target;
+               assert("nikita-2540",
+                      reiser4_carry_real(target) == insertion_node);
+       }
+       assert("nikita-2541",
+              reiser4_carry_real(op->node) == op->u.insert.d->coord->node);
+       return insertion_node;
+}
+
+/*
+ * complete make_space() call: update tracked lock handle if necessary. See
+ * comments for fs/reiser4/carry.h:carry_track_type
+ */
+static int
+make_space_tail(carry_op * op, carry_level * doing, znode * orig_node)
+{
+       int result;
+       carry_track_type tracking;
+       znode *node;
+
+       tracking = doing->track_type;
+       node = op->u.insert.d->coord->node;
+
+       if (tracking == CARRY_TRACK_NODE ||
+           (tracking == CARRY_TRACK_CHANGE && node != orig_node)) {
+               /* inserting or pasting into node different from
+                  original. Update lock handle supplied by caller. */
+               assert("nikita-1417", doing->tracked != NULL);
+               done_lh(doing->tracked);
+               init_lh(doing->tracked);
+               result = longterm_lock_znode(doing->tracked, node,
+                                            ZNODE_WRITE_LOCK,
+                                            ZNODE_LOCK_HIPRI);
+       } else
+               result = 0;
+       return result;
+}
+
+/* This is insertion policy function. It shifts data to the left and right
+   neighbors of insertion coord and allocates new nodes until there is enough
+   free space to complete @op.
+
+   See comments in the body.
+
+   Assumes that the node format favors insertions at the right end of the node
+   as node40 does.
+
+   See carry_flow() on detail about flow insertion
+*/
+static int make_space(carry_op * op /* carry operation, insert or paste */ ,
+                     carry_level * doing /* current carry queue */ ,
+                     carry_level * todo /* carry queue on the parent level */ )
+{
+       znode *node;
+       int result;
+       int not_enough_space;
+       int blk_alloc;
+       znode *orig_node;
+       __u32 flags;
+
+       coord_t *coord;
+
+       assert("nikita-890", op != NULL);
+       assert("nikita-891", todo != NULL);
+       assert("nikita-892",
+              op->op == COP_INSERT ||
+              op->op == COP_PASTE || op->op == COP_EXTENT);
+       assert("nikita-1607",
+              reiser4_carry_real(op->node) == op->u.insert.d->coord->node);
+
+       flags = op->u.insert.flags;
+
+       /* NOTE check that new node can only be allocated after checking left
+        * and right neighbors. This is necessary for proper work of
+        * find_{left,right}_neighbor(). */
+       assert("nikita-3410", ergo(flags & COPI_DONT_ALLOCATE,
+                                  flags & COPI_DONT_SHIFT_LEFT));
+       assert("nikita-3411", ergo(flags & COPI_DONT_ALLOCATE,
+                                  flags & COPI_DONT_SHIFT_RIGHT));
+
+       coord = op->u.insert.d->coord;
+       orig_node = node = coord->node;
+
+       assert("nikita-908", node != NULL);
+       assert("nikita-909", node_plugin_by_node(node) != NULL);
+
+       result = 0;
+       /* If there is not enough space in a node, try to shift something to
+          the left neighbor. This is a bit tricky, as locking to the left is
+          low priority. This is handled by restart logic in carry().
+        */
+       not_enough_space = free_space_shortage(node, op);
+       if (not_enough_space <= 0)
+               /* it is possible that carry was called when there actually
+                  was enough space in the node. For example, when inserting
+                  leftmost item so that delimiting keys have to be updated.
+                */
+               return make_space_tail(op, doing, orig_node);
+       if (!(flags & COPI_DONT_SHIFT_LEFT)) {
+               carry_node *left;
+               /* make note in statistics of an attempt to move
+                  something into the left neighbor */
+               left = find_left_neighbor(op, doing);
+               if (unlikely(IS_ERR(left))) {
+                       if (PTR_ERR(left) == -E_REPEAT)
+                               return -E_REPEAT;
+                       else {
+                               /* some error other than restart request
+                                  occurred. This shouldn't happen. Issue a
+                                  warning and continue as if left neighbor
+                                  weren't existing.
+                                */
+                               warning("nikita-924",
+                                       "Error accessing left neighbor: %li",
+                                       PTR_ERR(left));
+                       }
+               } else if (left != NULL) {
+
+                       /* shift everything possible on the left of and
+                          including insertion coord into the left neighbor */
+                       result = carry_shift_data(LEFT_SIDE, coord,
+                                                 reiser4_carry_real(left),
+                                                 doing, todo,
+                                                 flags & COPI_GO_LEFT);
+
+                       /* reget node from coord: shift_left() might move
+                          insertion coord to the left neighbor */
+                       node = sync_op(op, left);
+
+                       not_enough_space = free_space_shortage(node, op);
+                       /* There is not enough free space in @node, but
+                          may be, there is enough free space in
+                          @left. Various balancing decisions are valid here.
+                          The same for the shifiting to the right.
+                        */
+               }
+       }
+       /* If there still is not enough space, shift to the right */
+       if (not_enough_space > 0 && !(flags & COPI_DONT_SHIFT_RIGHT)) {
+               carry_node *right;
+
+               right = find_right_neighbor(op, doing);
+               if (IS_ERR(right)) {
+                       warning("nikita-1065",
+                               "Error accessing right neighbor: %li",
+                               PTR_ERR(right));
+               } else if (right != NULL) {
+                       /* node containing insertion point, and its right
+                          neighbor node are write locked by now.
+
+                          shift everything possible on the right of but
+                          excluding insertion coord into the right neighbor
+                        */
+                       result = carry_shift_data(RIGHT_SIDE, coord,
+                                                 reiser4_carry_real(right),
+                                                 doing, todo,
+                                                 flags & COPI_GO_RIGHT);
+                       /* reget node from coord: shift_right() might move
+                          insertion coord to the right neighbor */
+                       node = sync_op(op, right);
+                       not_enough_space = free_space_shortage(node, op);
+               }
+       }
+       /* If there is still not enough space, allocate new node(s).
+
+          We try to allocate new blocks if COPI_DONT_ALLOCATE is not set in
+          the carry operation flags (currently this is needed during flush
+          only).
+        */
+       for (blk_alloc = 0;
+            not_enough_space > 0 && result == 0 && blk_alloc < 2 &&
+            !(flags & COPI_DONT_ALLOCATE); ++blk_alloc) {
+               carry_node *fresh;      /* new node we are allocating */
+               coord_t coord_shadow;   /* remembered insertion point before
+                                        * shifting data into new node */
+               carry_node *node_shadow;        /* remembered insertion node before
+                                                * shifting */
+               unsigned int gointo;    /* whether insertion point should move
+                                        * into newly allocated node */
+
+               /* allocate new node on the right of @node. Znode and disk
+                  fake block number for new node are allocated.
+
+                  add_new_znode() posts carry operation COP_INSERT with
+                  COPT_CHILD option to the parent level to add
+                  pointer to newly created node to its parent.
+
+                  Subtle point: if several new nodes are required to complete
+                  insertion operation at this level, they will be inserted
+                  into their parents in the order of creation, which means
+                  that @node will be valid "cookie" at the time of insertion.
+
+                */
+               fresh = add_new_znode(node, op->node, doing, todo);
+               if (IS_ERR(fresh))
+                       return PTR_ERR(fresh);
+
+               /* Try to shift into new node. */
+               result = lock_carry_node(doing, fresh);
+               zput(reiser4_carry_real(fresh));
+               if (result != 0) {
+                       warning("nikita-947",
+                               "Cannot lock new node: %i", result);
+                       return result;
+               }
+
+               /* both nodes are write locked by now.
+
+                  shift everything possible on the right of and
+                  including insertion coord into the right neighbor.
+                */
+               coord_dup(&coord_shadow, op->u.insert.d->coord);
+               node_shadow = op->node;
+               /* move insertion point into newly created node if:
+
+                  . insertion point is rightmost in the source node, or
+                  . this is not the first node we are allocating in a row.
+                */
+               gointo =
+                   (blk_alloc > 0) ||
+                   coord_is_after_rightmost(op->u.insert.d->coord);
+
+               if (gointo &&
+                   op->op == COP_PASTE &&
+                   coord_is_existing_item(op->u.insert.d->coord) &&
+                   is_solid_item((item_plugin_by_coord(op->u.insert.d->coord)))) {
+                       /* paste into solid (atomic) item, which can contain
+                          only one unit, so we need to shift it right, where
+                          insertion point supposed to be */
+
+                       assert("edward-1444", op->u.insert.d->data->iplug ==
+                              item_plugin_by_id(STATIC_STAT_DATA_ID));
+                       assert("edward-1445",
+                              op->u.insert.d->data->length >
+                              node_plugin_by_node(coord->node)->free_space
+                              (coord->node));
+
+                       op->u.insert.d->coord->between = BEFORE_UNIT;
+               }
+
+               result = carry_shift_data(RIGHT_SIDE, coord,
+                                         reiser4_carry_real(fresh),
+                                         doing, todo, gointo);
+               /* if insertion point was actually moved into new node,
+                  update carry node pointer in operation. */
+               node = sync_op(op, fresh);
+               not_enough_space = free_space_shortage(node, op);
+               if ((not_enough_space > 0) && (node != coord_shadow.node)) {
+                       /* there is not enough free in new node. Shift
+                          insertion point back to the @shadow_node so that
+                          next new node would be inserted between
+                          @shadow_node and @fresh.
+                        */
+                       coord_normalize(&coord_shadow);
+                       coord_dup(coord, &coord_shadow);
+                       node = coord->node;
+                       op->node = node_shadow;
+                       if (1 || (flags & COPI_STEP_BACK)) {
+                               /* still not enough space?! Maybe there is
+                                  enough space in the source node (i.e., node
+                                  data are moved from) now.
+                                */
+                               not_enough_space =
+                                   free_space_shortage(node, op);
+                       }
+               }
+       }
+       if (not_enough_space > 0) {
+               if (!(flags & COPI_DONT_ALLOCATE))
+                       warning("nikita-948", "Cannot insert new item");
+               result = -E_NODE_FULL;
+       }
+       assert("nikita-1622", ergo(result == 0,
+                                 reiser4_carry_real(op->node) == coord->node));
+       assert("nikita-2616", coord == op->u.insert.d->coord);
+       if (result == 0)
+               result = make_space_tail(op, doing, orig_node);
+       return result;
+}
+
+/* insert_paste_common() - common part of insert and paste operations
+
+   This function performs common part of COP_INSERT and COP_PASTE.
+
+   There are two ways in which insertion/paste can be requested:
+
+    . by directly supplying reiser4_item_data. In this case, op ->
+    u.insert.type is set to COPT_ITEM_DATA.
+
+    . by supplying child pointer to which is to inserted into parent. In this
+    case op -> u.insert.type == COPT_CHILD.
+
+    . by supplying key of new item/unit. This is currently only used during
+    extent insertion
+
+   This is required, because when new node is allocated we don't know at what
+   position pointer to it is to be stored in the parent. Actually, we don't
+   even know what its parent will be, because parent can be re-balanced
+   concurrently and new node re-parented, and because parent can be full and
+   pointer to the new node will go into some other node.
+
+   insert_paste_common() resolves pointer to child node into position in the
+   parent by calling find_new_child_coord(), that fills
+   reiser4_item_data. After this, insertion/paste proceeds uniformly.
+
+   Another complication is with finding free space during pasting. It may
+   happen that while shifting items to the neighbors and newly allocated
+   nodes, insertion coord can no longer be in the item we wanted to paste
+   into. At this point, paste becomes (morphs) into insert. Moreover free
+   space analysis has to be repeated, because amount of space required for
+   insertion is different from that of paste (item header overhead, etc).
+
+   This function "unifies" different insertion modes (by resolving child
+   pointer or key into insertion coord), and then calls make_space() to free
+   enough space in the node by shifting data to the left and right and by
+   allocating new nodes if necessary. Carry operation knows amount of space
+   required for its completion. After enough free space is obtained, caller of
+   this function (carry_{insert,paste,etc.}) performs actual insertion/paste
+   by calling item plugin method.
+
+*/
+static int insert_paste_common(carry_op * op   /* carry operation being
+                                                * performed */ ,
+                              carry_level * doing /* current carry level */ ,
+                              carry_level * todo /* next carry level */ ,
+                              carry_insert_data * cdata        /* pointer to
+                                                                * cdata */ ,
+                              coord_t * coord /* insertion/paste coord */ ,
+                              reiser4_item_data * data /* data to be
+                                                        * inserted/pasted */ )
+{
+       assert("nikita-981", op != NULL);
+       assert("nikita-980", todo != NULL);
+       assert("nikita-979", (op->op == COP_INSERT) || (op->op == COP_PASTE)
+              || (op->op == COP_EXTENT));
+
+       if (op->u.insert.type == COPT_PASTE_RESTARTED) {
+               /* nothing to do. Fall through to make_space(). */
+               ;
+       } else if (op->u.insert.type == COPT_KEY) {
+               node_search_result intra_node;
+               znode *node;
+               /* Problem with doing batching at the lowest level, is that
+                  operations here are given by coords where modification is
+                  to be performed, and one modification can invalidate coords
+                  of all following operations.
+
+                  So, we are implementing yet another type for operation that
+                  will use (the only) "locator" stable across shifting of
+                  data between nodes, etc.: key (COPT_KEY).
+
+                  This clause resolves key to the coord in the node.
+
+                  But node can change also. Probably some pieces have to be
+                  added to the lock_carry_node(), to lock node by its key.
+
+                */
+               /* NOTE-NIKITA Lookup bias is fixed to FIND_EXACT. Complain
+                  if you need something else. */
+               op->u.insert.d->coord = coord;
+               node = reiser4_carry_real(op->node);
+               intra_node = node_plugin_by_node(node)->lookup
+                   (node, op->u.insert.d->key, FIND_EXACT,
+                    op->u.insert.d->coord);
+               if ((intra_node != NS_FOUND) && (intra_node != NS_NOT_FOUND)) {
+                       warning("nikita-1715", "Intra node lookup failure: %i",
+                               intra_node);
+                       return intra_node;
+               }
+       } else if (op->u.insert.type == COPT_CHILD) {
+               /* if we are asked to insert pointer to the child into
+                  internal node, first convert pointer to the child into
+                  coord within parent node.
+                */
+               znode *child;
+               int result;
+
+               op->u.insert.d = cdata;
+               op->u.insert.d->coord = coord;
+               op->u.insert.d->data = data;
+               op->u.insert.d->coord->node = reiser4_carry_real(op->node);
+               result = find_new_child_coord(op);
+               child = reiser4_carry_real(op->u.insert.child);
+               if (result != NS_NOT_FOUND) {
+                       warning("nikita-993",
+                               "Cannot find a place for child pointer: %i",
+                               result);
+                       return result;
+               }
+               /* This only happens when we did multiple insertions at
+                  the previous level, trying to insert single item and
+                  it so happened, that insertion of pointers to all new
+                  nodes before this one already caused parent node to
+                  split (may be several times).
+
+                  I am going to come up with better solution.
+
+                  You are not expected to understand this.
+                  -- v6root/usr/sys/ken/slp.c
+
+                  Basically, what happens here is the following: carry came
+                  to the parent level and is about to insert internal item
+                  pointing to the child node that it just inserted in the
+                  level below. Position where internal item is to be inserted
+                  was found by find_new_child_coord() above, but node of the
+                  current carry operation (that is, parent node of child
+                  inserted on the previous level), was determined earlier in
+                  the lock_carry_level/lock_carry_node. It could so happen
+                  that other carry operations already performed on the parent
+                  level already split parent node, so that insertion point
+                  moved into another node. Handle this by creating new carry
+                  node for insertion point if necessary.
+                */
+               if (reiser4_carry_real(op->node) !=
+                   op->u.insert.d->coord->node) {
+                       pool_ordering direction;
+                       znode *z1;
+                       znode *z2;
+                       reiser4_key k1;
+                       reiser4_key k2;
+
+                       /*
+                        * determine in what direction insertion point
+                        * moved. Do this by comparing delimiting keys.
+                        */
+                       z1 = op->u.insert.d->coord->node;
+                       z2 = reiser4_carry_real(op->node);
+                       if (keyle(leftmost_key_in_node(z1, &k1),
+                                 leftmost_key_in_node(z2, &k2)))
+                               /* insertion point moved to the left */
+                               direction = POOLO_BEFORE;
+                       else
+                               /* insertion point moved to the right */
+                               direction = POOLO_AFTER;
+
+                       op->node = reiser4_add_carry_skip(doing,
+                                                         direction, op->node);
+                       if (IS_ERR(op->node))
+                               return PTR_ERR(op->node);
+                       op->node->node = op->u.insert.d->coord->node;
+                       op->node->free = 1;
+                       result = lock_carry_node(doing, op->node);
+                       if (result != 0)
+                               return result;
+               }
+
+               /*
+                * set up key of an item being inserted: we are inserting
+                * internal item and its key is (by the very definition of
+                * search tree) is leftmost key in the child node.
+                */
+               write_lock_dk(znode_get_tree(child));
+               op->u.insert.d->key = leftmost_key_in_node(child,
+                                                          znode_get_ld_key(child));
+               write_unlock_dk(znode_get_tree(child));
+               op->u.insert.d->data->arg = op->u.insert.brother;
+       } else {
+               assert("vs-243", op->u.insert.d->coord != NULL);
+               op->u.insert.d->coord->node = reiser4_carry_real(op->node);
+       }
+
+       /* find free space. */
+       return make_space(op, doing, todo);
+}
+
+/* handle carry COP_INSERT operation.
+
+   Insert new item into node. New item can be given in one of two ways:
+
+   - by passing &tree_coord and &reiser4_item_data as part of @op. This is
+   only applicable at the leaf/twig level.
+
+   - by passing a child node pointer to which is to be inserted by this
+   operation.
+
+*/
+static int carry_insert(carry_op * op /* operation to perform */ ,
+                       carry_level * doing     /* queue of operations @op
+                                                * is part of */ ,
+                       carry_level * todo      /* queue where new operations
+                                                * are accumulated */ )
+{
+       znode *node;
+       carry_insert_data cdata;
+       coord_t coord;
+       reiser4_item_data data;
+       carry_plugin_info info;
+       int result;
+
+       assert("nikita-1036", op != NULL);
+       assert("nikita-1037", todo != NULL);
+       assert("nikita-1038", op->op == COP_INSERT);
+
+       coord_init_zero(&coord);
+
+       /* perform common functionality of insert and paste. */
+       result = insert_paste_common(op, doing, todo, &cdata, &coord, &data);
+       if (result != 0)
+               return result;
+
+       node = op->u.insert.d->coord->node;
+       assert("nikita-1039", node != NULL);
+       assert("nikita-1040", node_plugin_by_node(node) != NULL);
+
+       assert("nikita-949",
+              space_needed_for_op(node, op) <= znode_free_space(node));
+
+       /* ask node layout to create new item. */
+       info.doing = doing;
+       info.todo = todo;
+       result = node_plugin_by_node(node)->create_item
+           (op->u.insert.d->coord, op->u.insert.d->key, op->u.insert.d->data,
+            &info);
+       doing->restartable = 0;
+       znode_make_dirty(node);
+
+       return result;
+}
+
+/*
+ * Flow insertion code. COP_INSERT_FLOW is special tree operation that is
+ * supplied with a "flow" (that is, a stream of data) and inserts it into tree
+ * by slicing into multiple items.
+ */
+
+#define flow_insert_point(op) ( ( op ) -> u.insert_flow.insert_point )
+#define flow_insert_flow(op) ( ( op ) -> u.insert_flow.flow )
+#define flow_insert_data(op) ( ( op ) -> u.insert_flow.data )
+
+static size_t item_data_overhead(carry_op * op)
+{
+       if (flow_insert_data(op)->iplug->b.estimate == NULL)
+               return 0;
+       return (flow_insert_data(op)->iplug->b.
+               estimate(NULL /* estimate insertion */ , flow_insert_data(op)) -
+               flow_insert_data(op)->length);
+}
+
+/* FIXME-VS: this is called several times during one make_flow_for_insertion
+   and it will always return the same result. Some optimization could be made
+   by calculating this value once at the beginning and passing it around. That
+   would reduce some flexibility in future changes
+*/
+static int can_paste(coord_t *, const reiser4_key *, const reiser4_item_data *);
+static size_t flow_insertion_overhead(carry_op * op)
+{
+       znode *node;
+       size_t insertion_overhead;
+
+       node = flow_insert_point(op)->node;
+       insertion_overhead = 0;
+       if (node->nplug->item_overhead &&
+           !can_paste(flow_insert_point(op), &flow_insert_flow(op)->key,
+                      flow_insert_data(op)))
+               insertion_overhead =
+                   node->nplug->item_overhead(node, NULL) +
+                       item_data_overhead(op);
+       return insertion_overhead;
+}
+
+/* how many bytes of flow does fit to the node */
+static int what_can_fit_into_node(carry_op * op)
+{
+       size_t free, overhead;
+
+       overhead = flow_insertion_overhead(op);
+       free = znode_free_space(flow_insert_point(op)->node);
+       if (free <= overhead)
+               return 0;
+       free -= overhead;
+       /* FIXME: flow->length is loff_t only to not get overflowed in case of expandign truncate */
+       if (free < op->u.insert_flow.flow->length)
+               return free;
+       return (int)op->u.insert_flow.flow->length;
+}
+
+/* in make_space_for_flow_insertion we need to check either whether whole flow
+   fits into a node or whether minimal fraction of flow fits into a node */
+static int enough_space_for_whole_flow(carry_op * op)
+{
+       return (unsigned)what_can_fit_into_node(op) ==
+           op->u.insert_flow.flow->length;
+}
+
+#define MIN_FLOW_FRACTION 1
+static int enough_space_for_min_flow_fraction(carry_op * op)
+{
+       assert("vs-902", coord_is_after_rightmost(flow_insert_point(op)));
+
+       return what_can_fit_into_node(op) >= MIN_FLOW_FRACTION;
+}
+
+/* this returns 0 if left neighbor was obtained successfully and everything
+   upto insertion point including it were shifted and left neighbor still has
+   some free space to put minimal fraction of flow into it */
+static int
+make_space_by_shift_left(carry_op * op, carry_level * doing, carry_level * todo)
+{
+       carry_node *left;
+       znode *orig;
+
+       left = find_left_neighbor(op, doing);
+       if (unlikely(IS_ERR(left))) {
+               warning("vs-899",
+                       "make_space_by_shift_left: "
+                       "error accessing left neighbor: %li", PTR_ERR(left));
+               return 1;
+       }
+       if (left == NULL)
+               /* left neighbor either does not exist or is unformatted
+                  node */
+               return 1;
+
+       orig = flow_insert_point(op)->node;
+       /* try to shift content of node @orig from its head upto insert point
+          including insertion point into the left neighbor */
+       carry_shift_data(LEFT_SIDE, flow_insert_point(op),
+                        reiser4_carry_real(left), doing, todo,
+                        1 /* including insert point */);
+       if (reiser4_carry_real(left) != flow_insert_point(op)->node) {
+               /* insertion point did not move */
+               return 1;
+       }
+
+       /* insertion point is set after last item in the node */
+       assert("vs-900", coord_is_after_rightmost(flow_insert_point(op)));
+
+       if (!enough_space_for_min_flow_fraction(op)) {
+               /* insertion point node does not have enough free space to put
+                  even minimal portion of flow into it, therefore, move
+                  insertion point back to orig node (before first item) */
+               coord_init_before_first_item(flow_insert_point(op), orig);
+               return 1;
+       }
+
+       /* part of flow is to be written to the end of node */
+       op->node = left;
+       return 0;
+}
+
+/* this returns 0 if right neighbor was obtained successfully and everything to
+   the right of insertion point was shifted to it and node got enough free
+   space to put minimal fraction of flow into it */
+static int
+make_space_by_shift_right(carry_op * op, carry_level * doing,
+                         carry_level * todo)
+{
+       carry_node *right;
+
+       right = find_right_neighbor(op, doing);
+       if (unlikely(IS_ERR(right))) {
+               warning("nikita-1065", "shift_right_excluding_insert_point: "
+                       "error accessing right neighbor: %li", PTR_ERR(right));
+               return 1;
+       }
+       if (right) {
+               /* shift everything possible on the right of but excluding
+                  insertion coord into the right neighbor */
+               carry_shift_data(RIGHT_SIDE, flow_insert_point(op),
+                                reiser4_carry_real(right), doing, todo,
+                                0 /* not including insert point */);
+       } else {
+               /* right neighbor either does not exist or is unformatted
+                  node */
+               ;
+       }
+       if (coord_is_after_rightmost(flow_insert_point(op))) {
+               if (enough_space_for_min_flow_fraction(op)) {
+                       /* part of flow is to be written to the end of node */
+                       return 0;
+               }
+       }
+
+       /* new node is to be added if insert point node did not get enough
+          space for whole flow */
+       return 1;
+}
+
+/* this returns 0 when insert coord is set at the node end and fraction of flow
+   fits into that node */
+static int
+make_space_by_new_nodes(carry_op * op, carry_level * doing, carry_level * todo)
+{
+       int result;
+       znode *node;
+       carry_node *new;
+
+       node = flow_insert_point(op)->node;
+
+       if (op->u.insert_flow.new_nodes == CARRY_FLOW_NEW_NODES_LIMIT)
+               return RETERR(-E_NODE_FULL);
+       /* add new node after insert point node */
+       new = add_new_znode(node, op->node, doing, todo);
+       if (unlikely(IS_ERR(new))) {
+               return PTR_ERR(new);
+       }
+       result = lock_carry_node(doing, new);
+       zput(reiser4_carry_real(new));
+       if (unlikely(result)) {
+               return result;
+       }
+       op->u.insert_flow.new_nodes++;
+       if (!coord_is_after_rightmost(flow_insert_point(op))) {
+               carry_shift_data(RIGHT_SIDE, flow_insert_point(op),
+                                reiser4_carry_real(new), doing, todo,
+                                0 /* not including insert point */);
+               assert("vs-901",
+                      coord_is_after_rightmost(flow_insert_point(op)));
+
+               if (enough_space_for_min_flow_fraction(op)) {
+                       return 0;
+               }
+               if (op->u.insert_flow.new_nodes == CARRY_FLOW_NEW_NODES_LIMIT)
+                       return RETERR(-E_NODE_FULL);
+
+               /* add one more new node */
+               new = add_new_znode(node, op->node, doing, todo);
+               if (unlikely(IS_ERR(new))) {
+                       return PTR_ERR(new);
+               }
+               result = lock_carry_node(doing, new);
+               zput(reiser4_carry_real(new));
+               if (unlikely(result)) {
+                       return result;
+               }
+               op->u.insert_flow.new_nodes++;
+       }
+
+       /* move insertion point to new node */
+       coord_init_before_first_item(flow_insert_point(op),
+                                    reiser4_carry_real(new));
+       op->node = new;
+       return 0;
+}
+
+static int
+make_space_for_flow_insertion(carry_op * op, carry_level * doing,
+                             carry_level * todo)
+{
+       __u32 flags = op->u.insert_flow.flags;
+
+       if (enough_space_for_whole_flow(op)) {
+               /* whole flow fits into insert point node */
+               return 0;
+       }
+
+       if (!(flags & COPI_DONT_SHIFT_LEFT)
+           && (make_space_by_shift_left(op, doing, todo) == 0)) {
+               /* insert point is shifted to left neighbor of original insert
+                  point node and is set after last unit in that node. It has
+                  enough space to fit at least minimal fraction of flow. */
+               return 0;
+       }
+
+       if (enough_space_for_whole_flow(op)) {
+               /* whole flow fits into insert point node */
+               return 0;
+       }
+
+       if (!(flags & COPI_DONT_SHIFT_RIGHT)
+           && (make_space_by_shift_right(op, doing, todo) == 0)) {
+               /* insert point is still set to the same node, but there is
+                  nothing to the right of insert point. */
+               return 0;
+       }
+
+       if (enough_space_for_whole_flow(op)) {
+               /* whole flow fits into insert point node */
+               return 0;
+       }
+
+       return make_space_by_new_nodes(op, doing, todo);
+}
+
+/* implements COP_INSERT_FLOW operation */
+static int
+carry_insert_flow(carry_op * op, carry_level * doing, carry_level * todo)
+{
+       int result;
+       flow_t *f;
+       coord_t *insert_point;
+       node_plugin *nplug;
+       carry_plugin_info info;
+       znode *orig_node;
+       lock_handle *orig_lh;
+
+       f = op->u.insert_flow.flow;
+       result = 0;
+
+       /* carry system needs this to work */
+       info.doing = doing;
+       info.todo = todo;
+
+       orig_node = flow_insert_point(op)->node;
+       orig_lh = doing->tracked;
+
+       while (f->length) {
+               result = make_space_for_flow_insertion(op, doing, todo);
+               if (result)
+                       break;
+
+               insert_point = flow_insert_point(op);
+               nplug = node_plugin_by_node(insert_point->node);
+
+               /* compose item data for insertion/pasting */
+               flow_insert_data(op)->data = f->data;
+               flow_insert_data(op)->length = what_can_fit_into_node(op);
+
+               if (can_paste(insert_point, &f->key, flow_insert_data(op))) {
+                       /* insert point is set to item of file we are writing to and we have to append to it */
+                       assert("vs-903", insert_point->between == AFTER_UNIT);
+                       nplug->change_item_size(insert_point,
+                                               flow_insert_data(op)->length);
+                       flow_insert_data(op)->iplug->b.paste(insert_point,
+                                                            flow_insert_data
+                                                            (op), &info);
+               } else {
+                       /* new item must be inserted */
+                       pos_in_node_t new_pos;
+                       flow_insert_data(op)->length += item_data_overhead(op);
+
+                       /* FIXME-VS: this is because node40_create_item changes
+                          insert_point for obscure reasons */
+                       switch (insert_point->between) {
+                       case AFTER_ITEM:
+                               new_pos = insert_point->item_pos + 1;
+                               break;
+                       case EMPTY_NODE:
+                               new_pos = 0;
+                               break;
+                       case BEFORE_ITEM:
+                               assert("vs-905", insert_point->item_pos == 0);
+                               new_pos = 0;
+                               break;
+                       default:
+                               impossible("vs-906",
+                                          "carry_insert_flow: invalid coord");
+                               new_pos = 0;
+                               break;
+                       }
+
+                       nplug->create_item(insert_point, &f->key,
+                                          flow_insert_data(op), &info);
+                       coord_set_item_pos(insert_point, new_pos);
+               }
+               coord_init_after_item_end(insert_point);
+               doing->restartable = 0;
+               znode_make_dirty(insert_point->node);
+
+               move_flow_forward(f, (unsigned)flow_insert_data(op)->length);
+       }
+
+       if (orig_node != flow_insert_point(op)->node) {
+               /* move lock to new insert point */
+               done_lh(orig_lh);
+               init_lh(orig_lh);
+               result =
+                   longterm_lock_znode(orig_lh, flow_insert_point(op)->node,
+                                       ZNODE_WRITE_LOCK, ZNODE_LOCK_HIPRI);
+       }
+
+       return result;
+}
+
+/* implements COP_DELETE operation
+
+   Remove pointer to @op -> u.delete.child from it's parent.
+
+   This function also handles killing of a tree root is last pointer from it
+   was removed. This is complicated by our handling of "twig" level: root on
+   twig level is never killed.
+
+*/
+static int carry_delete(carry_op * op /* operation to be performed */ ,
+                       carry_level * doing UNUSED_ARG  /* current carry
+                                                        * level */ ,
+                       carry_level * todo /* next carry level */ )
+{
+       int result;
+       coord_t coord;
+       coord_t coord2;
+       znode *parent;
+       znode *child;
+       carry_plugin_info info;
+       reiser4_tree *tree;
+
+       /*
+        * This operation is called to delete internal item pointing to the
+        * child node that was removed by carry from the tree on the previous
+        * tree level.
+        */
+
+       assert("nikita-893", op != NULL);
+       assert("nikita-894", todo != NULL);
+       assert("nikita-895", op->op == COP_DELETE);
+
+       coord_init_zero(&coord);
+       coord_init_zero(&coord2);
+
+       parent = reiser4_carry_real(op->node);
+       child = op->u.delete.child ?
+               reiser4_carry_real(op->u.delete.child) : op->node->node;
+       tree = znode_get_tree(child);
+       read_lock_tree(tree);
+
+       /*
+        * @parent was determined when carry entered parent level
+        * (lock_carry_level/lock_carry_node). Since then, actual parent of
+        * @child node could change due to other carry operations performed on
+        * the parent level. Check for this.
+        */
+
+       if (znode_parent(child) != parent) {
+               /* NOTE-NIKITA add stat counter for this. */
+               parent = znode_parent(child);
+               assert("nikita-2581", find_carry_node(doing, parent));
+       }
+       read_unlock_tree(tree);
+
+       assert("nikita-1213", znode_get_level(parent) > LEAF_LEVEL);
+
+       /* Twig level horrors: tree should be of height at least 2. So, last
+          pointer from the root at twig level is preserved even if child is
+          empty. This is ugly, but so it was architectured.
+        */
+
+       if (znode_is_root(parent) &&
+           znode_get_level(parent) <= REISER4_MIN_TREE_HEIGHT &&
+           node_num_items(parent) == 1) {
+               /* Delimiting key manipulations. */
+               write_lock_dk(tree);
+               znode_set_ld_key(child, znode_set_ld_key(parent, reiser4_min_key()));
+               znode_set_rd_key(child, znode_set_rd_key(parent, reiser4_max_key()));
+               ZF_SET(child, JNODE_DKSET);
+               write_unlock_dk(tree);
+
+               /* @child escaped imminent death! */
+               ZF_CLR(child, JNODE_HEARD_BANSHEE);
+               return 0;
+       }
+
+       /* convert child pointer to the coord_t */
+       result = find_child_ptr(parent, child, &coord);
+       if (result != NS_FOUND) {
+               warning("nikita-994", "Cannot find child pointer: %i", result);
+               print_coord_content("coord", &coord);
+               return result;
+       }
+
+       coord_dup(&coord2, &coord);
+       info.doing = doing;
+       info.todo = todo;
+       {
+               /*
+                * Actually kill internal item: prepare structure with
+                * arguments for ->cut_and_kill() method...
+                */
+
+               struct carry_kill_data kdata;
+               kdata.params.from = &coord;
+               kdata.params.to = &coord2;
+               kdata.params.from_key = NULL;
+               kdata.params.to_key = NULL;
+               kdata.params.smallest_removed = NULL;
+               kdata.params.truncate = 1;
+               kdata.flags = op->u.delete.flags;
+               kdata.inode = NULL;
+               kdata.left = NULL;
+               kdata.right = NULL;
+               kdata.buf = NULL;
+               /* ... and call it. */
+               result = node_plugin_by_node(parent)->cut_and_kill(&kdata,
+                                                                  &info);
+       }
+       doing->restartable = 0;
+
+       /* check whether root should be killed violently */
+       if (znode_is_root(parent) &&
+           /* don't kill roots at and lower than twig level */
+           znode_get_level(parent) > REISER4_MIN_TREE_HEIGHT &&
+           node_num_items(parent) == 1) {
+               result = reiser4_kill_tree_root(coord.node);
+       }
+
+       return result < 0 ? : 0;
+}
+
+/* implements COP_CUT opration
+
+   Cuts part or whole content of node.
+
+*/
+static int carry_cut(carry_op * op /* operation to be performed */ ,
+                    carry_level * doing /* current carry level */ ,
+                    carry_level * todo /* next carry level */ )
+{
+       int result;
+       carry_plugin_info info;
+       node_plugin *nplug;
+
+       assert("nikita-896", op != NULL);
+       assert("nikita-897", todo != NULL);
+       assert("nikita-898", op->op == COP_CUT);
+
+       info.doing = doing;
+       info.todo = todo;
+
+       nplug = node_plugin_by_node(reiser4_carry_real(op->node));
+       if (op->u.cut_or_kill.is_cut)
+               result = nplug->cut(op->u.cut_or_kill.u.cut, &info);
+       else
+               result = nplug->cut_and_kill(op->u.cut_or_kill.u.kill, &info);
+
+       doing->restartable = 0;
+       return result < 0 ? : 0;
+}
+
+/* helper function for carry_paste(): returns true if @op can be continued as
+   paste  */
+static int
+can_paste(coord_t * icoord, const reiser4_key * key,
+         const reiser4_item_data * data)
+{
+       coord_t circa;
+       item_plugin *new_iplug;
+       item_plugin *old_iplug;
+       int result = 0;         /* to keep gcc shut */
+
+       assert("", icoord->between != AT_UNIT);
+
+       /* obviously, one cannot paste when node is empty---there is nothing
+          to paste into. */
+       if (node_is_empty(icoord->node))
+               return 0;
+       /* if insertion point is at the middle of the item, then paste */
+       if (!coord_is_between_items(icoord))
+               return 1;
+       coord_dup(&circa, icoord);
+       circa.between = AT_UNIT;
+
+       old_iplug = item_plugin_by_coord(&circa);
+       new_iplug = data->iplug;
+
+       /* check whether we can paste to the item @icoord is "at" when we
+          ignore ->between field */
+       if (old_iplug == new_iplug && item_can_contain_key(&circa, key, data)) {
+               result = 1;
+       } else if (icoord->between == BEFORE_UNIT
+                  || icoord->between == BEFORE_ITEM) {
+               /* otherwise, try to glue to the item at the left, if any */
+               coord_dup(&circa, icoord);
+               if (coord_set_to_left(&circa)) {
+                       result = 0;
+                       coord_init_before_item(icoord);
+               } else {
+                       old_iplug = item_plugin_by_coord(&circa);
+                       result = (old_iplug == new_iplug)
+                           && item_can_contain_key(icoord, key, data);
+                       if (result) {
+                               coord_dup(icoord, &circa);
+                               icoord->between = AFTER_UNIT;
+                       }
+               }
+       } else if (icoord->between == AFTER_UNIT
+                  || icoord->between == AFTER_ITEM) {
+               coord_dup(&circa, icoord);
+               /* otherwise, try to glue to the item at the right, if any */
+               if (coord_set_to_right(&circa)) {
+                       result = 0;
+                       coord_init_after_item(icoord);
+               } else {
+                       int (*cck) (const coord_t *, const reiser4_key *,
+                                   const reiser4_item_data *);
+
+                       old_iplug = item_plugin_by_coord(&circa);
+
+                       cck = old_iplug->b.can_contain_key;
+                       if (cck == NULL)
+                               /* item doesn't define ->can_contain_key
+                                  method? So it is not expandable. */
+                               result = 0;
+                       else {
+                               result = (old_iplug == new_iplug)
+                                   && cck(&circa /*icoord */ , key, data);
+                               if (result) {
+                                       coord_dup(icoord, &circa);
+                                       icoord->between = BEFORE_UNIT;
+                               }
+                       }
+               }
+       } else
+               impossible("nikita-2513", "Nothing works");
+       if (result) {
+               if (icoord->between == BEFORE_ITEM) {
+                       assert("vs-912", icoord->unit_pos == 0);
+                       icoord->between = BEFORE_UNIT;
+               } else if (icoord->between == AFTER_ITEM) {
+                       coord_init_after_item_end(icoord);
+               }
+       }
+       return result;
+}
+
+/* implements COP_PASTE operation
+
+   Paste data into existing item. This is complicated by the fact that after
+   we shifted something to the left or right neighbors trying to free some
+   space, item we were supposed to paste into can be in different node than
+   insertion coord. If so, we are no longer doing paste, but insert. See
+   comments in insert_paste_common().
+
+*/
+static int carry_paste(carry_op * op /* operation to be performed */ ,
+                      carry_level * doing UNUSED_ARG   /* current carry
+                                                        * level */ ,
+                      carry_level * todo /* next carry level */ )
+{
+       znode *node;
+       carry_insert_data cdata;
+       coord_t dcoord;
+       reiser4_item_data data;
+       int result;
+       int real_size;
+       item_plugin *iplug;
+       carry_plugin_info info;
+       coord_t *coord;
+
+       assert("nikita-982", op != NULL);
+       assert("nikita-983", todo != NULL);
+       assert("nikita-984", op->op == COP_PASTE);
+
+       coord_init_zero(&dcoord);
+
+       result = insert_paste_common(op, doing, todo, &cdata, &dcoord, &data);
+       if (result != 0)
+               return result;
+
+       coord = op->u.insert.d->coord;
+
+       /* handle case when op -> u.insert.coord doesn't point to the item
+          of required type. restart as insert. */
+       if (!can_paste(coord, op->u.insert.d->key, op->u.insert.d->data)) {
+               op->op = COP_INSERT;
+               op->u.insert.type = COPT_PASTE_RESTARTED;
+               result = op_dispatch_table[COP_INSERT].handler(op, doing, todo);
+
+               return result;
+       }
+
+       node = coord->node;
+       iplug = item_plugin_by_coord(coord);
+       assert("nikita-992", iplug != NULL);
+
+       assert("nikita-985", node != NULL);
+       assert("nikita-986", node_plugin_by_node(node) != NULL);
+
+       assert("nikita-987",
+              space_needed_for_op(node, op) <= znode_free_space(node));
+
+       assert("nikita-1286", coord_is_existing_item(coord));
+
+       /*
+        * if item is expanded as a result of this operation, we should first
+        * change item size, than call ->b.paste item method. If item is
+        * shrunk, it should be done other way around: first call ->b.paste
+        * method, then reduce item size.
+        */
+
+       real_size = space_needed_for_op(node, op);
+       if (real_size > 0)
+               node->nplug->change_item_size(coord, real_size);
+
+       doing->restartable = 0;
+       info.doing = doing;
+       info.todo = todo;
+
+       result = iplug->b.paste(coord, op->u.insert.d->data, &info);
+
+       if (real_size < 0)
+               node->nplug->change_item_size(coord, real_size);
+
+       /* if we pasted at the beginning of the item, update item's key. */
+       if (coord->unit_pos == 0 && coord->between != AFTER_UNIT)
+               node->nplug->update_item_key(coord, op->u.insert.d->key, &info);
+
+       znode_make_dirty(node);
+       return result;
+}
+
+/* handle carry COP_EXTENT operation. */
+static int carry_extent(carry_op * op /* operation to perform */ ,
+                       carry_level * doing     /* queue of operations @op
+                                                * is part of */ ,
+                       carry_level * todo      /* queue where new operations
+                                                * are accumulated */ )
+{
+       znode *node;
+       carry_insert_data cdata;
+       coord_t coord;
+       reiser4_item_data data;
+       carry_op *delete_dummy;
+       carry_op *insert_extent;
+       int result;
+       carry_plugin_info info;
+
+       assert("nikita-1751", op != NULL);
+       assert("nikita-1752", todo != NULL);
+       assert("nikita-1753", op->op == COP_EXTENT);
+
+       /* extent insertion overview:
+
+          extents live on the TWIG LEVEL, which is level one above the leaf
+          one. This complicates extent insertion logic somewhat: it may
+          happen (and going to happen all the time) that in logical key
+          ordering extent has to be placed between items I1 and I2, located
+          at the leaf level, but I1 and I2 are in the same formatted leaf
+          node N1. To insert extent one has to
+
+          (1) reach node N1 and shift data between N1, its neighbors and
+          possibly newly allocated nodes until I1 and I2 fall into different
+          nodes. Since I1 and I2 are still neighboring items in logical key
+          order, they will be necessary utmost items in their respective
+          nodes.
+
+          (2) After this new extent item is inserted into node on the twig
+          level.
+
+          Fortunately this process can reuse almost all code from standard
+          insertion procedure (viz. make_space() and insert_paste_common()),
+          due to the following observation: make_space() only shifts data up
+          to and excluding or including insertion point. It never
+          "over-moves" through insertion point. Thus, one can use
+          make_space() to perform step (1). All required for this is just to
+          instruct free_space_shortage() to keep make_space() shifting data
+          until insertion point is at the node border.
+
+        */
+
+       /* perform common functionality of insert and paste. */
+       result = insert_paste_common(op, doing, todo, &cdata, &coord, &data);
+       if (result != 0)
+               return result;
+
+       node = op->u.extent.d->coord->node;
+       assert("nikita-1754", node != NULL);
+       assert("nikita-1755", node_plugin_by_node(node) != NULL);
+       assert("nikita-1700", coord_wrt(op->u.extent.d->coord) != COORD_INSIDE);
+
+       /* NOTE-NIKITA add some checks here. Not assertions, -EIO. Check that
+          extent fits between items. */
+
+       info.doing = doing;
+       info.todo = todo;
+
+       /* there is another complication due to placement of extents on the
+          twig level: extents are "rigid" in the sense that key-range
+          occupied by extent cannot grow indefinitely to the right as it is
+          for the formatted leaf nodes. Because of this when search finds two
+          adjacent extents on the twig level, it has to "drill" to the leaf
+          level, creating new node. Here we are removing this node.
+        */
+       if (node_is_empty(node)) {
+               delete_dummy = node_post_carry(&info, COP_DELETE, node, 1);
+               if (IS_ERR(delete_dummy))
+                       return PTR_ERR(delete_dummy);
+               delete_dummy->u.delete.child = NULL;
+               delete_dummy->u.delete.flags = DELETE_RETAIN_EMPTY;
+               ZF_SET(node, JNODE_HEARD_BANSHEE);
+       }
+
+       /* proceed with inserting extent item into parent. We are definitely
+          inserting rather than pasting if we get that far. */
+       insert_extent = node_post_carry(&info, COP_INSERT, node, 1);
+       if (IS_ERR(insert_extent))
+               /* @delete_dummy will be automatically destroyed on the level
+                  exiting  */
+               return PTR_ERR(insert_extent);
+       /* NOTE-NIKITA insertion by key is simplest option here. Another
+          possibility is to insert on the left or right of already existing
+          item.
+        */
+       insert_extent->u.insert.type = COPT_KEY;
+       insert_extent->u.insert.d = op->u.extent.d;
+       assert("nikita-1719", op->u.extent.d->key != NULL);
+       insert_extent->u.insert.d->data->arg = op->u.extent.d->coord;
+       insert_extent->u.insert.flags =
+           znode_get_tree(node)->carry.new_extent_flags;
+
+       /*
+        * if carry was asked to track lock handle we should actually track
+        * lock handle on the twig node rather than on the leaf where
+        * operation was started from. Transfer tracked lock handle.
+        */
+       if (doing->track_type) {
+               assert("nikita-3242", doing->tracked != NULL);
+               assert("nikita-3244", todo->tracked == NULL);
+               todo->tracked = doing->tracked;
+               todo->track_type = CARRY_TRACK_NODE;
+               doing->tracked = NULL;
+               doing->track_type = 0;
+       }
+
+       return 0;
+}
+
+/* update key in @parent between pointers to @left and @right.
+
+   Find coords of @left and @right and update delimiting key between them.
+   This is helper function called by carry_update(). Finds position of
+   internal item involved. Updates item key. Updates delimiting keys of child
+   nodes involved.
+*/
+static int update_delimiting_key(znode * parent        /* node key is updated
+                                                * in */ ,
+                                znode * left /* child of @parent */ ,
+                                znode * right /* child of @parent */ ,
+                                carry_level * doing    /* current carry
+                                                        * level */ ,
+                                carry_level * todo     /* parent carry
+                                                        * level */ ,
+                                const char **error_msg /* place to
+                                                        * store error
+                                                        * message */ )
+{
+       coord_t left_pos;
+       coord_t right_pos;
+       int result;
+       reiser4_key ldkey;
+       carry_plugin_info info;
+
+       assert("nikita-1177", right != NULL);
+       /* find position of right left child in a parent */
+       result = find_child_ptr(parent, right, &right_pos);
+       if (result != NS_FOUND) {
+               *error_msg = "Cannot find position of right child";
+               return result;
+       }
+
+       if ((left != NULL) && !coord_is_leftmost_unit(&right_pos)) {
+               /* find position of the left child in a parent */
+               result = find_child_ptr(parent, left, &left_pos);
+               if (result != NS_FOUND) {
+                       *error_msg = "Cannot find position of left child";
+                       return result;
+               }
+               assert("nikita-1355", left_pos.node != NULL);
+       } else
+               left_pos.node = NULL;
+
+       /* check that they are separated by exactly one key and are basically
+          sane */
+       if (REISER4_DEBUG) {
+               if ((left_pos.node != NULL)
+                   && !coord_is_existing_unit(&left_pos)) {
+                       *error_msg = "Left child is bastard";
+                       return RETERR(-EIO);
+               }
+               if (!coord_is_existing_unit(&right_pos)) {
+                       *error_msg = "Right child is bastard";
+                       return RETERR(-EIO);
+               }
+               if (left_pos.node != NULL &&
+                   !coord_are_neighbors(&left_pos, &right_pos)) {
+                       *error_msg = "Children are not direct siblings";
+                       return RETERR(-EIO);
+               }
+       }
+       *error_msg = NULL;
+
+       info.doing = doing;
+       info.todo = todo;
+
+       /*
+        * If child node is not empty, new key of internal item is a key of
+        * leftmost item in the child node. If the child is empty, take its
+        * right delimiting key as a new key of the internal item. Precise key
+        * in the latter case is not important per se, because the child (and
+        * the internal item) are going to be killed shortly anyway, but we
+        * have to preserve correct order of keys in the parent node.
+        */
+
+       if (!ZF_ISSET(right, JNODE_HEARD_BANSHEE))
+               leftmost_key_in_node(right, &ldkey);
+       else {
+               read_lock_dk(znode_get_tree(parent));
+               ldkey = *znode_get_rd_key(right);
+               read_unlock_dk(znode_get_tree(parent));
+       }
+       node_plugin_by_node(parent)->update_item_key(&right_pos, &ldkey, &info);
+       doing->restartable = 0;
+       znode_make_dirty(parent);
+       return 0;
+}
+
+/* implements COP_UPDATE opration
+
+   Update delimiting keys.
+
+*/
+static int carry_update(carry_op * op /* operation to be performed */ ,
+                       carry_level * doing /* current carry level */ ,
+                       carry_level * todo /* next carry level */ )
+{
+       int result;
+       carry_node *missing UNUSED_ARG;
+       znode *left;
+       znode *right;
+       carry_node *lchild;
+       carry_node *rchild;
+       const char *error_msg;
+       reiser4_tree *tree;
+
+       /*
+        * This operation is called to update key of internal item. This is
+        * necessary when carry shifted of cut data on the child
+        * level. Arguments of this operation are:
+        *
+        *     @right --- child node. Operation should update key of internal
+        *     item pointing to @right.
+        *
+        *     @left --- left neighbor of @right. This parameter is optional.
+        */
+
+       assert("nikita-902", op != NULL);
+       assert("nikita-903", todo != NULL);
+       assert("nikita-904", op->op == COP_UPDATE);
+
+       lchild = op->u.update.left;
+       rchild = op->node;
+
+       if (lchild != NULL) {
+               assert("nikita-1001", lchild->parent);
+               assert("nikita-1003", !lchild->left);
+               left = reiser4_carry_real(lchild);
+       } else
+               left = NULL;
+
+       tree = znode_get_tree(rchild->node);
+       read_lock_tree(tree);
+       right = znode_parent(rchild->node);
+       read_unlock_tree(tree);
+
+       if (right != NULL) {
+               result = update_delimiting_key(right,
+                                              lchild ? lchild->node : NULL,
+                                              rchild->node,
+                                              doing, todo, &error_msg);
+       } else {
+               error_msg = "Cannot find node to update key in";
+               result = RETERR(-EIO);
+       }
+       /* operation will be reposted to the next level by the
+          ->update_item_key() method of node plugin, if necessary. */
+
+       if (result != 0) {
+               warning("nikita-999", "Error updating delimiting key: %s (%i)",
+                       error_msg ? : "", result);
+       }
+       return result;
+}
+
+/* move items from @node during carry */
+static int carry_shift_data(sideof side /* in what direction to move data */ ,
+                           coord_t * insert_coord      /* coord where new item
+                                                        * is to be inserted */ ,
+                           znode * node /* node which data are moved from */ ,
+                           carry_level * doing /* active carry queue */ ,
+                           carry_level * todo  /* carry queue where new
+                                                * operations are to be put
+                                                * in */ ,
+                           unsigned int including_insert_coord_p       /* true if
+                                                                        * @insertion_coord
+                                                                        * can be moved */ )
+{
+       int result;
+       znode *source;
+       carry_plugin_info info;
+       node_plugin *nplug;
+
+       source = insert_coord->node;
+
+       info.doing = doing;
+       info.todo = todo;
+
+       nplug = node_plugin_by_node(node);
+       result = nplug->shift(insert_coord, node,
+                             (side == LEFT_SIDE) ? SHIFT_LEFT : SHIFT_RIGHT, 0,
+                             (int)including_insert_coord_p, &info);
+       /* the only error ->shift() method of node plugin can return is
+          -ENOMEM due to carry node/operation allocation. */
+       assert("nikita-915", result >= 0 || result == -ENOMEM);
+       if (result > 0) {
+               /*
+                * if some number of bytes was actually shifted, mark nodes
+                * dirty, and carry level as non-restartable.
+                */
+               doing->restartable = 0;
+               znode_make_dirty(source);
+               znode_make_dirty(node);
+       }
+
+       assert("nikita-2077", coord_check(insert_coord));
+       return 0;
+}
+
+typedef carry_node *(*carry_iterator) (carry_node * node);
+static carry_node *find_dir_carry(carry_node * node, carry_level * level,
+                                 carry_iterator iterator);
+
+static carry_node *pool_level_list_prev(carry_node *node)
+{
+       return list_entry(node->header.level_linkage.prev, carry_node, header.level_linkage);
+}
+
+/* look for the left neighbor of given carry node in a carry queue.
+
+   This is used by find_left_neighbor(), but I am not sure that this
+   really gives any advantage. More statistics required.
+
+*/
+carry_node *find_left_carry(carry_node * node  /* node to find left neighbor
+                                                * of */ ,
+                           carry_level * level /* level to scan */ )
+{
+       return find_dir_carry(node, level,
+                             (carry_iterator) pool_level_list_prev);
+}
+
+static carry_node *pool_level_list_next(carry_node *node)
+{
+       return list_entry(node->header.level_linkage.next, carry_node, header.level_linkage);
+}
+
+/* look for the right neighbor of given carry node in a
+   carry queue.
+
+   This is used by find_right_neighbor(), but I am not sure that this
+   really gives any advantage. More statistics required.
+
+*/
+carry_node *find_right_carry(carry_node * node /* node to find right neighbor
+                                                * of */ ,
+                            carry_level * level /* level to scan */ )
+{
+       return find_dir_carry(node, level,
+                             (carry_iterator) pool_level_list_next);
+}
+
+/* look for the left or right neighbor of given carry node in a carry
+   queue.
+
+   Helper function used by find_{left|right}_carry().
+*/
+static carry_node *find_dir_carry(carry_node * node    /* node to start scanning
+                                                        * from */ ,
+                                 carry_level * level /* level to scan */ ,
+                                 carry_iterator iterator       /* operation to
+                                                                * move to the next
+                                                                * node */ )
+{
+       carry_node *neighbor;
+
+       assert("nikita-1059", node != NULL);
+       assert("nikita-1060", level != NULL);
+
+       /* scan list of carry nodes on this list dir-ward, skipping all
+          carry nodes referencing the same znode. */
+       neighbor = node;
+       while (1) {
+               neighbor = iterator(neighbor);
+               if (carry_node_end(level, neighbor))
+                       /* list head is reached */
+                       return NULL;
+               if (reiser4_carry_real(neighbor) != reiser4_carry_real(node))
+                       return neighbor;
+       }
+}
+
+/*
+ * Memory reservation estimation.
+ *
+ * Carry process proceeds through tree levels upwards. Carry assumes that it
+ * takes tree in consistent state (e.g., that search tree invariants hold),
+ * and leaves tree consistent after it finishes. This means that when some
+ * error occurs carry cannot simply return if there are pending carry
+ * operations. Generic solution for this problem is carry-undo either as
+ * transaction manager feature (requiring checkpoints and isolation), or
+ * through some carry specific mechanism.
+ *
+ * Our current approach is to panic if carry hits an error while tree is
+ * inconsistent. Unfortunately -ENOMEM can easily be triggered. To work around
+ * this "memory reservation" mechanism was added.
+ *
+ * Memory reservation is implemented by perthread-pages.diff patch from
+ * core-patches. Its API is defined in <linux/gfp.h>
+ *
+ *     int  perthread_pages_reserve(int nrpages, gfp_t gfp);
+ *     void perthread_pages_release(int nrpages);
+ *     int  perthread_pages_count(void);
+ *
+ * carry estimates its worst case memory requirements at the entry, reserved
+ * enough memory, and released unused pages before returning.
+ *
+ * Code below estimates worst case memory requirements for a given carry
+ * queue. This is dome by summing worst case memory requirements for each
+ * operation in the queue.
+ *
+ */
+
+/*
+ * Memory memory requirements of many operations depends on the tree
+ * height. For example, item insertion requires new node to be inserted at
+ * each tree level in the worst case. What tree height should be used for
+ * estimation? Current tree height is wrong, because tree height can change
+ * between the time when estimation was done and the time when operation is
+ * actually performed. Maximal possible tree height (REISER4_MAX_ZTREE_HEIGHT)
+ * is also not desirable, because it would lead to the huge over-estimation
+ * all the time. Plausible solution is "capped tree height": if current tree
+ * height is less than some TREE_HEIGHT_CAP constant, capped tree height is
+ * TREE_HEIGHT_CAP, otherwise it's current tree height. Idea behind this is
+ * that if tree height is TREE_HEIGHT_CAP or larger, it's extremely unlikely
+ * to be increased even more during short interval of time.
+ */
+#define TREE_HEIGHT_CAP (5)
+
+/* return capped tree height for the @tree. See comment above. */
+static int cap_tree_height(reiser4_tree * tree)
+{
+       return max_t(int, tree->height, TREE_HEIGHT_CAP);
+}
+
+/* return capped tree height for the current tree. */
+static int capped_height(void)
+{
+       return cap_tree_height(current_tree);
+}
+
+/* return number of pages required to store given number of bytes */
+static int bytes_to_pages(int bytes)
+{
+       return (bytes + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+}
+
+/* how many pages are required to allocate znodes during item insertion. */
+static int carry_estimate_znodes(void)
+{
+       /*
+        * Note, that there we have some problem here: there is no way to
+        * reserve pages specifically for the given slab. This means that
+        * these pages can be hijacked for some other end.
+        */
+
+       /* in the worst case we need 3 new znode on each tree level */
+       return bytes_to_pages(capped_height() * sizeof(znode) * 3);
+}
+
+/*
+ * how many pages are required to load bitmaps. One bitmap per level.
+ */
+static int carry_estimate_bitmaps(void)
+{
+       if (reiser4_is_set(reiser4_get_current_sb(), REISER4_DONT_LOAD_BITMAP)) {
+               int bytes;
+
+               bytes = capped_height() * (0 +  /* bnode should be added, but its is private to
+                                                * bitmap.c, skip for now. */
+                                          2 * sizeof(jnode));  /* working and commit jnodes */
+               return bytes_to_pages(bytes) + 2;       /* and their contents */
+       } else
+               /* bitmaps were pre-loaded during mount */
+               return 0;
+}
+
+/* worst case item insertion memory requirements */
+static int carry_estimate_insert(carry_op * op, carry_level * level)
+{
+       return carry_estimate_bitmaps() + carry_estimate_znodes() + 1 + /* new atom */
+           capped_height() +   /* new block on each level */
+           1 +                 /* and possibly extra new block at the leaf level */
+           3;                  /* loading of leaves into memory */
+}
+
+/* worst case item deletion memory requirements */
+static int carry_estimate_delete(carry_op * op, carry_level * level)
+{
+       return carry_estimate_bitmaps() + carry_estimate_znodes() + 1 + /* new atom */
+           3;                  /* loading of leaves into memory */
+}
+
+/* worst case tree cut memory requirements */
+static int carry_estimate_cut(carry_op * op, carry_level * level)
+{
+       return carry_estimate_bitmaps() + carry_estimate_znodes() + 1 + /* new atom */
+           3;                  /* loading of leaves into memory */
+}
+
+/* worst case memory requirements of pasting into item */
+static int carry_estimate_paste(carry_op * op, carry_level * level)
+{
+       return carry_estimate_bitmaps() + carry_estimate_znodes() + 1 + /* new atom */
+           capped_height() +   /* new block on each level */
+           1 +                 /* and possibly extra new block at the leaf level */
+           3;                  /* loading of leaves into memory */
+}
+
+/* worst case memory requirements of extent insertion */
+static int carry_estimate_extent(carry_op * op, carry_level * level)
+{
+       return carry_estimate_insert(op, level) +       /* insert extent */
+           carry_estimate_delete(op, level);   /* kill leaf */
+}
+
+/* worst case memory requirements of key update */
+static int carry_estimate_update(carry_op * op, carry_level * level)
+{
+       return 0;
+}
+
+/* worst case memory requirements of flow insertion */
+static int carry_estimate_insert_flow(carry_op * op, carry_level * level)
+{
+       int newnodes;
+
+       newnodes = min(bytes_to_pages(op->u.insert_flow.flow->length),
+                      CARRY_FLOW_NEW_NODES_LIMIT);
+       /*
+        * roughly estimate insert_flow as a sequence of insertions.
+        */
+       return newnodes * carry_estimate_insert(op, level);
+}
+
+/* This is dispatch table for carry operations. It can be trivially
+   abstracted into useful plugin: tunable balancing policy is a good
+   thing. */
+carry_op_handler op_dispatch_table[COP_LAST_OP] = {
+       [COP_INSERT] = {
+                       .handler = carry_insert,
+                       .estimate = carry_estimate_insert}
+       ,
+       [COP_DELETE] = {
+                       .handler = carry_delete,
+                       .estimate = carry_estimate_delete}
+       ,
+       [COP_CUT] = {
+                    .handler = carry_cut,
+                    .estimate = carry_estimate_cut}
+       ,
+       [COP_PASTE] = {
+                      .handler = carry_paste,
+                      .estimate = carry_estimate_paste}
+       ,
+       [COP_EXTENT] = {
+                       .handler = carry_extent,
+                       .estimate = carry_estimate_extent}
+       ,
+       [COP_UPDATE] = {
+                       .handler = carry_update,
+                       .estimate = carry_estimate_update}
+       ,
+       [COP_INSERT_FLOW] = {
+                            .handler = carry_insert_flow,
+                            .estimate = carry_estimate_insert_flow}
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/carry_ops.h linux-2.6.20/fs/reiser4/carry_ops.h
--- linux-2.6.20.orig/fs/reiser4/carry_ops.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/carry_ops.h 2007-05-06 14:50:43.694974475 +0400
@@ -0,0 +1,42 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* implementation of carry operations. See carry_ops.c for details. */
+
+#if !defined( __CARRY_OPS_H__ )
+#define __CARRY_OPS_H__
+
+#include "forward.h"
+#include "znode.h"
+#include "carry.h"
+
+/* carry operation handlers */
+typedef struct carry_op_handler {
+       /* perform operation */
+       int (*handler) (carry_op * op, carry_level * doing, carry_level * todo);
+       /* estimate memory requirements for @op */
+       int (*estimate) (carry_op * op, carry_level * level);
+} carry_op_handler;
+
+/* This is dispatch table for carry operations. It can be trivially
+   abstracted into useful plugin: tunable balancing policy is a good
+   thing. */
+extern carry_op_handler op_dispatch_table[COP_LAST_OP];
+
+unsigned int space_needed(const znode * node, const coord_t * coord,
+                         const reiser4_item_data * data, int inserting);
+extern carry_node *find_left_carry(carry_node * node, carry_level * level);
+extern carry_node *find_right_carry(carry_node * node, carry_level * level);
+
+/* __CARRY_OPS_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/context.c linux-2.6.20/fs/reiser4/context.c
--- linux-2.6.20.orig/fs/reiser4/context.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/context.c   2007-05-06 14:50:43.694974475 +0400
@@ -0,0 +1,288 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Manipulation of reiser4_context */
+
+/*
+ * global context used during system call. Variable of this type is allocated
+ * on the stack at the beginning of the reiser4 part of the system call and
+ * pointer to it is stored in the current->fs_context. This allows us to avoid
+ * passing pointer to current transaction and current lockstack (both in
+ * one-to-one mapping with threads) all over the call chain.
+ *
+ * It's kind of like those global variables the prof used to tell you not to
+ * use in CS1, except thread specific.;-) Nikita, this was a good idea.
+ *
+ * In some situations it is desirable to have ability to enter reiser4_context
+ * more than once for the same thread (nested contexts). For example, there
+ * are some functions that can be called either directly from VFS/VM or from
+ * already active reiser4 context (->writepage, for example).
+ *
+ * In such situations "child" context acts like dummy: all activity is
+ * actually performed in the top level context, and get_current_context()
+ * always returns top level context.
+ * Of course, reiser4_init_context()/reiser4_done_context() have to be properly
+ * nested any way.
+ *
+ * Note that there is an important difference between reiser4 uses
+ * ->fs_context and the way other file systems use it. Other file systems
+ * (ext3 and reiserfs) use ->fs_context only for the duration of _transaction_
+ * (this is why ->fs_context was initially called ->journal_info). This means,
+ * that when ext3 or reiserfs finds that ->fs_context is not NULL on the entry
+ * to the file system, they assume that some transaction is already underway,
+ * and usually bail out, because starting nested transaction would most likely
+ * lead to the deadlock. This gives false positives with reiser4, because we
+ * set ->fs_context before starting transaction.
+ */
+
+#include "debug.h"
+#include "super.h"
+#include "context.h"
+
+#include <linux/writeback.h>   /* balance_dirty_pages() */
+#include <linux/hardirq.h>
+
+static void _reiser4_init_context(reiser4_context * context,
+                                 struct super_block *super)
+{
+       memset(context, 0, sizeof(*context));
+
+       context->super = super;
+       context->magic = context_magic;
+       context->outer = current->journal_info;
+       current->journal_info = (void *)context;
+       context->nr_children = 0;
+       context->gfp_mask = GFP_KERNEL;
+
+       init_lock_stack(&context->stack);
+
+       reiser4_txn_begin(context);
+
+       /* initialize head of tap list */
+       INIT_LIST_HEAD(&context->taps);
+#if REISER4_DEBUG
+       context->task = current;
+#endif
+       grab_space_enable();
+}
+
+/* initialize context and bind it to the current thread
+
+   This function should be called at the beginning of reiser4 part of
+   syscall.
+*/
+reiser4_context * reiser4_init_context(struct super_block * super)
+{
+       reiser4_context *context;
+
+       assert("nikita-2662", !in_interrupt() && !in_irq());
+       assert("nikita-3357", super != NULL);
+       assert("nikita-3358", super->s_op == NULL || is_reiser4_super(super));
+
+       context = get_current_context_check();
+       if (context && context->super == super) {
+               context = (reiser4_context *) current->journal_info;
+               context->nr_children++;
+               return context;
+       }
+
+       context = kmalloc(sizeof(*context), GFP_KERNEL);
+       if (context == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+
+       _reiser4_init_context(context, super);
+       return context;
+}
+
+/* this is used in scan_mgr which is called with spinlock held and in
+   reiser4_fill_super magic */
+void init_stack_context(reiser4_context *context, struct super_block *super)
+{
+       assert("nikita-2662", !in_interrupt() && !in_irq());
+       assert("nikita-3357", super != NULL);
+       assert("nikita-3358", super->s_op == NULL || is_reiser4_super(super));
+       assert("vs-12", !is_in_reiser4_context());
+
+       _reiser4_init_context(context, super);
+       context->on_stack = 1;
+       return;
+}
+
+/* cast lock stack embedded into reiser4 context up to its container */
+reiser4_context *get_context_by_lock_stack(lock_stack * owner)
+{
+       return container_of(owner, reiser4_context, stack);
+}
+
+/* true if there is already _any_ reiser4 context for the current thread */
+int is_in_reiser4_context(void)
+{
+       reiser4_context *ctx;
+
+       ctx = current->journal_info;
+       return ctx != NULL && ((unsigned long)ctx->magic) == context_magic;
+}
+
+/*
+ * call balance dirty pages for the current context.
+ *
+ * File system is expected to call balance_dirty_pages_ratelimited() whenever
+ * it dirties a page. reiser4 does this for unformatted nodes (that is, during
+ * write---this covers vast majority of all dirty traffic), but we cannot do
+ * this immediately when formatted node is dirtied, because long term lock is
+ * usually held at that time. To work around this, dirtying of formatted node
+ * simply increases ->nr_marked_dirty counter in the current reiser4
+ * context. When we are about to leave this context,
+ * balance_dirty_pages_ratelimited() is called, if necessary.
+ *
+ * This introduces another problem: sometimes we do not want to run
+ * balance_dirty_pages_ratelimited() when leaving a context, for example
+ * because some important lock (like ->i_mutex on the parent directory) is
+ * held. To achieve this, ->nobalance flag can be set in the current context.
+ */
+static void balance_dirty_pages_at(reiser4_context *context)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(context->super);
+
+       /*
+        * call balance_dirty_pages_ratelimited() to process formatted nodes
+        * dirtied during this system call. Do that only if we are not in mount
+        * and there were nodes dirtied in this context and we are not in
+        * writepage (to avoid deadlock) and not in pdflush
+        */
+       if (sbinfo != NULL && sbinfo->fake != NULL &&
+           context->nr_marked_dirty != 0 &&
+           !(current->flags & PF_MEMALLOC) &&
+           !current_is_pdflush())
+               balance_dirty_pages_ratelimited(sbinfo->fake->i_mapping);
+}
+
+/* release resources associated with context.
+
+   This function should be called at the end of "session" with reiser4,
+   typically just before leaving reiser4 driver back to VFS.
+
+   This is good place to put some degugging consistency checks, like that
+   thread released all locks and closed transcrash etc.
+
+*/
+static void reiser4_done_context(reiser4_context * context /* context being released */ )
+{
+       assert("nikita-860", context != NULL);
+       assert("nikita-859", context->magic == context_magic);
+       assert("vs-646", (reiser4_context *) current->journal_info == context);
+       assert("zam-686", !in_interrupt() && !in_irq());
+
+       /* only do anything when leaving top-level reiser4 context. All nested
+        * contexts are just dummies. */
+       if (context->nr_children == 0) {
+               assert("jmacd-673", context->trans == NULL);
+               assert("jmacd-1002", lock_stack_isclean(&context->stack));
+               assert("nikita-1936", reiser4_no_counters_are_held());
+               assert("nikita-2626", list_empty_careful(reiser4_taps_list()));
+               assert("zam-1004", ergo(get_super_private(context->super),
+                                       get_super_private(context->super)->delete_mutex_owner !=
+                                       current));
+
+               /* release all grabbed but as yet unused blocks */
+               if (context->grabbed_blocks != 0)
+                       all_grabbed2free();
+
+               /*
+                * synchronize against longterm_unlock_znode():
+                * wake_up_requestor() wakes up requestors without holding
+                * zlock (otherwise they will immediately bump into that lock
+                * after wake up on another CPU). To work around (rare)
+                * situation where requestor has been woken up asynchronously
+                * and managed to run until completion (and destroy its
+                * context and lock stack) before wake_up_requestor() called
+                * wake_up() on it, wake_up_requestor() synchronize on lock
+                * stack spin lock. It has actually been observed that spin
+                * lock _was_ locked at this point, because
+                * wake_up_requestor() took interrupt.
+                */
+               spin_lock_stack(&context->stack);
+               spin_unlock_stack(&context->stack);
+
+               assert("zam-684", context->nr_children == 0);
+               /* restore original ->fs_context value */
+               current->journal_info = context->outer;
+               if (context->on_stack == 0)
+                       kfree(context);
+       } else {
+               context->nr_children--;
+#if REISER4_DEBUG
+               assert("zam-685", context->nr_children >= 0);
+#endif
+       }
+}
+
+/*
+ * exit reiser4 context. Call balance_dirty_pages_at() if necessary. Close
+ * transaction. Call done_context() to do context related book-keeping.
+ */
+void reiser4_exit_context(reiser4_context * context)
+{
+       assert("nikita-3021", reiser4_schedulable());
+
+       if (context->nr_children == 0) {
+               if (!context->nobalance) {
+                       reiser4_txn_restart(context);
+                       balance_dirty_pages_at(context);
+               }
+
+               /* if filesystem is mounted with -o sync or -o dirsync - commit
+                  transaction.  FIXME: TXNH_DONT_COMMIT is used to avoid
+                  commiting on exit_context when inode semaphore is held and
+                  to have ktxnmgrd to do commit instead to get better
+                  concurrent filesystem accesses. But, when one mounts with -o
+                  sync, he cares more about reliability than about
+                  performance. So, for now we have this simple mount -o sync
+                  support. */
+               if (context->super->s_flags & (MS_SYNCHRONOUS | MS_DIRSYNC)) {
+                       txn_atom *atom;
+
+                       atom = get_current_atom_locked_nocheck();
+                       if (atom) {
+                               atom->flags |= ATOM_FORCE_COMMIT;
+                               context->trans->flags &= ~TXNH_DONT_COMMIT;
+                               spin_unlock_atom(atom);
+                       }
+               }
+               reiser4_txn_end(context);
+       }
+       reiser4_done_context(context);
+}
+
+void reiser4_ctx_gfp_mask_set(void)
+{
+       reiser4_context *ctx;
+
+       ctx = get_current_context();
+       if (ctx->entd == 0 &&
+           list_empty(&ctx->stack.locks) &&
+           ctx->trans->atom == NULL)
+               ctx->gfp_mask = GFP_KERNEL;
+       else
+               ctx->gfp_mask = GFP_NOFS;
+}
+
+void reiser4_ctx_gfp_mask_force (gfp_t mask)
+{
+       reiser4_context *ctx;
+       ctx = get_current_context();
+
+       assert("edward-1454", ctx != NULL);
+
+       ctx->gfp_mask = mask;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/context.h linux-2.6.20/fs/reiser4/context.h
--- linux-2.6.20.orig/fs/reiser4/context.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/context.h   2007-05-06 14:50:43.698975725 +0400
@@ -0,0 +1,228 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Reiser4 context. See context.c for details. */
+
+#if !defined( __REISER4_CONTEXT_H__ )
+#define __REISER4_CONTEXT_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "tap.h"
+#include "lock.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/spinlock.h>
+#include <linux/sched.h>       /* for struct task_struct */
+
+/* reiser4 per-thread context */
+struct reiser4_context {
+       /* magic constant. For identification of reiser4 contexts. */
+       __u32 magic;
+
+       /* current lock stack. See lock.[ch]. This is where list of all
+          locks taken by current thread is kept. This is also used in
+          deadlock detection. */
+       lock_stack stack;
+
+       /* current transcrash. */
+       txn_handle *trans;
+       /* transaction handle embedded into reiser4_context. ->trans points
+        * here by default. */
+       txn_handle trans_in_ctx;
+
+       /* super block we are working with.  To get the current tree
+          use &get_super_private (reiser4_get_current_sb ())->tree. */
+       struct super_block *super;
+
+       /* parent fs activation */
+       struct fs_activation *outer;
+
+       /* per-thread grabbed (for further allocation) blocks counter */
+       reiser4_block_nr grabbed_blocks;
+
+       /* list of taps currently monitored. See tap.c */
+       struct list_head taps;
+
+       /* grabbing space is enabled */
+       unsigned int grab_enabled:1;
+       /* should be set when we are write dirty nodes to disk in jnode_flush or
+        * reiser4_write_logs() */
+       unsigned int writeout_mode:1;
+       /* true, if current thread is an ent thread */
+       unsigned int entd:1;
+       /* true, if balance_dirty_pages() should not be run when leaving this
+        * context. This is used to avoid lengthly balance_dirty_pages()
+        * operation when holding some important resource, like directory
+        * ->i_mutex */
+       unsigned int nobalance:1;
+
+       /* this bit is used on reiser4_done_context to decide whether context is
+          kmalloc-ed and has to be kfree-ed */
+       unsigned int on_stack:1;
+
+       /* count non-trivial jnode_set_dirty() calls */
+       unsigned long nr_marked_dirty;
+
+       /* reiser4_sync_inodes calls (via generic_sync_sb_inodes)
+        * reiser4_writepages for each of dirty inodes. Reiser4_writepages
+        * captures pages. When number of pages captured in one
+        * reiser4_sync_inodes reaches some threshold - some atoms get
+        * flushed */
+       int nr_captured;
+       int nr_children;        /* number of child contexts */
+#if REISER4_DEBUG
+       /* debugging information about reiser4 locks held by the current
+        * thread */
+       reiser4_lock_counters_info locks;
+       struct task_struct *task;       /* so we can easily find owner of the stack */
+
+       /*
+        * disk space grabbing debugging support
+        */
+       /* how many disk blocks were grabbed by the first call to
+        * reiser4_grab_space() in this context */
+       reiser4_block_nr grabbed_initially;
+
+       /* list of all threads doing flush currently */
+       struct list_head flushers_link;
+       /* information about last error encountered by reiser4 */
+       err_site err;
+#endif
+       void *vp;
+       gfp_t gfp_mask;
+};
+
+extern reiser4_context *get_context_by_lock_stack(lock_stack *);
+
+/* Debugging helps. */
+#if REISER4_DEBUG
+extern void print_contexts(void);
+#endif
+
+#define current_tree (&(get_super_private(reiser4_get_current_sb())->tree))
+#define current_blocksize reiser4_get_current_sb()->s_blocksize
+#define current_blocksize_bits reiser4_get_current_sb()->s_blocksize_bits
+
+extern reiser4_context *reiser4_init_context(struct super_block *);
+extern void init_stack_context(reiser4_context *, struct super_block *);
+extern void reiser4_exit_context(reiser4_context *);
+
+/* magic constant we store in reiser4_context allocated at the stack. Used to
+   catch accesses to staled or uninitialized contexts. */
+#define context_magic ((__u32) 0x4b1b5d0b)
+
+extern int is_in_reiser4_context(void);
+
+/*
+ * return reiser4_context for the thread @tsk
+ */
+static inline reiser4_context *get_context(const struct task_struct *tsk)
+{
+       assert("vs-1682",
+              ((reiser4_context *) tsk->journal_info)->magic == context_magic);
+       return (reiser4_context *) tsk->journal_info;
+}
+
+/*
+ * return reiser4 context of the current thread, or NULL if there is none.
+ */
+static inline reiser4_context *get_current_context_check(void)
+{
+       if (is_in_reiser4_context())
+               return get_context(current);
+       else
+               return NULL;
+}
+
+static inline reiser4_context *get_current_context(void);      /* __attribute__((const)); */
+
+/* return context associated with current thread */
+static inline reiser4_context *get_current_context(void)
+{
+       return get_context(current);
+}
+
+static inline gfp_t reiser4_ctx_gfp_mask_get(void)
+{
+       reiser4_context *ctx;
+
+       ctx = get_current_context_check();
+       return (ctx == NULL) ? GFP_KERNEL : ctx->gfp_mask;
+}
+
+void reiser4_ctx_gfp_mask_set(void);
+void reiser4_ctx_gfp_mask_force (gfp_t mask);
+
+/*
+ * true if current thread is in the write-out mode. Thread enters write-out
+ * mode during jnode_flush and reiser4_write_logs().
+ */
+static inline int is_writeout_mode(void)
+{
+       return get_current_context()->writeout_mode;
+}
+
+/*
+ * enter write-out mode
+ */
+static inline void writeout_mode_enable(void)
+{
+       assert("zam-941", !get_current_context()->writeout_mode);
+       get_current_context()->writeout_mode = 1;
+}
+
+/*
+ * leave write-out mode
+ */
+static inline void writeout_mode_disable(void)
+{
+       assert("zam-942", get_current_context()->writeout_mode);
+       get_current_context()->writeout_mode = 0;
+}
+
+static inline void grab_space_enable(void)
+{
+       get_current_context()->grab_enabled = 1;
+}
+
+static inline void grab_space_disable(void)
+{
+       get_current_context()->grab_enabled = 0;
+}
+
+static inline void grab_space_set_enabled(int enabled)
+{
+       get_current_context()->grab_enabled = enabled;
+}
+
+static inline int is_grab_enabled(reiser4_context * ctx)
+{
+       return ctx->grab_enabled;
+}
+
+/* mark transaction handle in @ctx as TXNH_DONT_COMMIT, so that no commit or
+ * flush would be performed when it is closed. This is necessary when handle
+ * has to be closed under some coarse semaphore, like i_mutex of
+ * directory. Commit will be performed by ktxnmgrd. */
+static inline void context_set_commit_async(reiser4_context * context)
+{
+       context->nobalance = 1;
+       context->trans->flags |= TXNH_DONT_COMMIT;
+}
+
+/* __REISER4_CONTEXT_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/coord.c linux-2.6.20/fs/reiser4/coord.c
--- linux-2.6.20.orig/fs/reiser4/coord.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/coord.c     2007-05-06 14:50:43.698975725 +0400
@@ -0,0 +1,935 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "tree.h"
+#include "plugin/item/item.h"
+#include "znode.h"
+#include "coord.h"
+
+/* Internal constructor. */
+static inline void
+coord_init_values(coord_t * coord, const znode * node, pos_in_node_t item_pos,
+                 pos_in_node_t unit_pos, between_enum between)
+{
+       coord->node = (znode *) node;
+       coord_set_item_pos(coord, item_pos);
+       coord->unit_pos = unit_pos;
+       coord->between = between;
+       ON_DEBUG(coord->plug_v = 0);
+       ON_DEBUG(coord->body_v = 0);
+
+       /*ON_TRACE (TRACE_COORDS, "init coord %p node %p: %u %u %s\n", coord, node, item_pos, unit_pos, coord_tween_tostring (between)); */
+}
+
+/* after shifting of node content, coord previously set properly may become
+   invalid, try to "normalize" it. */
+void coord_normalize(coord_t * coord)
+{
+       znode *node;
+
+       node = coord->node;
+       assert("vs-683", node);
+
+       coord_clear_iplug(coord);
+
+       if (node_is_empty(node)) {
+               coord_init_first_unit(coord, node);
+       } else if ((coord->between == AFTER_ITEM)
+                  || (coord->between == AFTER_UNIT)) {
+               return;
+       } else if (coord->item_pos == coord_num_items(coord)
+                  && coord->between == BEFORE_ITEM) {
+               coord_dec_item_pos(coord);
+               coord->between = AFTER_ITEM;
+       } else if (coord->unit_pos == coord_num_units(coord)
+                  && coord->between == BEFORE_UNIT) {
+               coord->unit_pos--;
+               coord->between = AFTER_UNIT;
+       } else if (coord->item_pos == coord_num_items(coord)
+                  && coord->unit_pos == 0 && coord->between == BEFORE_UNIT) {
+               coord_dec_item_pos(coord);
+               coord->unit_pos = 0;
+               coord->between = AFTER_ITEM;
+       }
+}
+
+/* Copy a coordinate. */
+void coord_dup(coord_t * coord, const coord_t * old_coord)
+{
+       assert("jmacd-9800", coord_check(old_coord));
+       coord_dup_nocheck(coord, old_coord);
+}
+
+/* Copy a coordinate without check. Useful when old_coord->node is not
+   loaded. As in cbk_tree_lookup -> connect_znode -> connect_one_side */
+void coord_dup_nocheck(coord_t * coord, const coord_t * old_coord)
+{
+       coord->node = old_coord->node;
+       coord_set_item_pos(coord, old_coord->item_pos);
+       coord->unit_pos = old_coord->unit_pos;
+       coord->between = old_coord->between;
+       coord->iplugid = old_coord->iplugid;
+       ON_DEBUG(coord->plug_v = old_coord->plug_v);
+       ON_DEBUG(coord->body_v = old_coord->body_v);
+}
+
+/* Initialize an invalid coordinate. */
+void coord_init_invalid(coord_t * coord, const znode * node)
+{
+       coord_init_values(coord, node, 0, 0, INVALID_COORD);
+}
+
+void coord_init_first_unit_nocheck(coord_t * coord, const znode * node)
+{
+       coord_init_values(coord, node, 0, 0, AT_UNIT);
+}
+
+/* Initialize a coordinate to point at the first unit of the first item.  If the node is
+   empty, it is positioned at the EMPTY_NODE. */
+void coord_init_first_unit(coord_t * coord, const znode * node)
+{
+       int is_empty = node_is_empty(node);
+
+       coord_init_values(coord, node, 0, 0, (is_empty ? EMPTY_NODE : AT_UNIT));
+
+       assert("jmacd-9801", coord_check(coord));
+}
+
+/* Initialize a coordinate to point at the last unit of the last item.  If the node is
+   empty, it is positioned at the EMPTY_NODE. */
+void coord_init_last_unit(coord_t * coord, const znode * node)
+{
+       int is_empty = node_is_empty(node);
+
+       coord_init_values(coord, node,
+                         (is_empty ? 0 : node_num_items(node) - 1), 0,
+                         (is_empty ? EMPTY_NODE : AT_UNIT));
+       if (!is_empty)
+               coord->unit_pos = coord_last_unit_pos(coord);
+       assert("jmacd-9802", coord_check(coord));
+}
+
+/* Initialize a coordinate to before the first item.  If the node is empty, it is
+   positioned at the EMPTY_NODE. */
+void coord_init_before_first_item(coord_t * coord, const znode * node)
+{
+       int is_empty = node_is_empty(node);
+
+       coord_init_values(coord, node, 0, 0,
+                         (is_empty ? EMPTY_NODE : BEFORE_UNIT));
+
+       assert("jmacd-9803", coord_check(coord));
+}
+
+/* Initialize a coordinate to after the last item.  If the node is empty, it is positioned
+   at the EMPTY_NODE. */
+void coord_init_after_last_item(coord_t * coord, const znode * node)
+{
+       int is_empty = node_is_empty(node);
+
+       coord_init_values(coord, node,
+                         (is_empty ? 0 : node_num_items(node) - 1), 0,
+                         (is_empty ? EMPTY_NODE : AFTER_ITEM));
+
+       assert("jmacd-9804", coord_check(coord));
+}
+
+/* Initialize a coordinate to after last unit in the item. Coord must be set
+   already to existing item */
+void coord_init_after_item_end(coord_t * coord)
+{
+       coord->between = AFTER_UNIT;
+       coord->unit_pos = coord_last_unit_pos(coord);
+}
+
+/* Initialize a coordinate to before the item. Coord must be set already to existing item */
+void coord_init_before_item(coord_t * coord)
+{
+       coord->unit_pos = 0;
+       coord->between = BEFORE_ITEM;
+}
+
+/* Initialize a coordinate to after the item. Coord must be set already to existing item */
+void coord_init_after_item(coord_t * coord)
+{
+       coord->unit_pos = 0;
+       coord->between = AFTER_ITEM;
+}
+
+/* Initialize a coordinate by 0s. Used in places where init_coord was used and
+   it was not clear how actually */
+void coord_init_zero(coord_t * coord)
+{
+       memset(coord, 0, sizeof(*coord));
+}
+
+/* Return the number of units at the present item.  Asserts coord_is_existing_item(). */
+unsigned coord_num_units(const coord_t * coord)
+{
+       assert("jmacd-9806", coord_is_existing_item(coord));
+
+       return item_plugin_by_coord(coord)->b.nr_units(coord);
+}
+
+/* Returns true if the coord was initializewd by coord_init_invalid (). */
+/* Audited by: green(2002.06.15) */
+int coord_is_invalid(const coord_t * coord)
+{
+       return coord->between == INVALID_COORD;
+}
+
+/* Returns true if the coordinate is positioned at an existing item, not before or after
+   an item.  It may be placed at, before, or after any unit within the item, whether
+   existing or not. */
+int coord_is_existing_item(const coord_t * coord)
+{
+       switch (coord->between) {
+       case EMPTY_NODE:
+       case BEFORE_ITEM:
+       case AFTER_ITEM:
+       case INVALID_COORD:
+               return 0;
+
+       case BEFORE_UNIT:
+       case AT_UNIT:
+       case AFTER_UNIT:
+               return coord->item_pos < coord_num_items(coord);
+       }
+
+       impossible("jmacd-9900", "unreachable coord: %p", coord);
+       return 0;
+}
+
+/* Returns true if the coordinate is positioned at an existing unit, not before or after a
+   unit. */
+/* Audited by: green(2002.06.15) */
+int coord_is_existing_unit(const coord_t * coord)
+{
+       switch (coord->between) {
+       case EMPTY_NODE:
+       case BEFORE_UNIT:
+       case AFTER_UNIT:
+       case BEFORE_ITEM:
+       case AFTER_ITEM:
+       case INVALID_COORD:
+               return 0;
+
+       case AT_UNIT:
+               return (coord->item_pos < coord_num_items(coord)
+                       && coord->unit_pos < coord_num_units(coord));
+       }
+
+       impossible("jmacd-9902", "unreachable");
+       return 0;
+}
+
+/* Returns true if the coordinate is positioned at the first unit of the first item.  Not
+   true for empty nodes nor coordinates positioned before the first item. */
+/* Audited by: green(2002.06.15) */
+int coord_is_leftmost_unit(const coord_t * coord)
+{
+       return (coord->between == AT_UNIT && coord->item_pos == 0
+               && coord->unit_pos == 0);
+}
+
+#if REISER4_DEBUG
+/* For assertions only, checks for a valid coordinate. */
+int coord_check(const coord_t * coord)
+{
+       if (coord->node == NULL) {
+               return 0;
+       }
+       if (znode_above_root(coord->node))
+               return 1;
+
+       switch (coord->between) {
+       default:
+       case INVALID_COORD:
+               return 0;
+       case EMPTY_NODE:
+               if (!node_is_empty(coord->node)) {
+                       return 0;
+               }
+               return coord->item_pos == 0 && coord->unit_pos == 0;
+
+       case BEFORE_UNIT:
+       case AFTER_UNIT:
+               if (node_is_empty(coord->node) && (coord->item_pos == 0)
+                   && (coord->unit_pos == 0))
+                       return 1;
+       case AT_UNIT:
+               break;
+       case AFTER_ITEM:
+       case BEFORE_ITEM:
+               /* before/after item should not set unit_pos. */
+               if (coord->unit_pos != 0) {
+                       return 0;
+               }
+               break;
+       }
+
+       if (coord->item_pos >= node_num_items(coord->node)) {
+               return 0;
+       }
+
+       /* FIXME-VS: we are going to check unit_pos. This makes no sense when
+          between is set either AFTER_ITEM or BEFORE_ITEM */
+       if (coord->between == AFTER_ITEM || coord->between == BEFORE_ITEM)
+               return 1;
+
+       if (coord_is_iplug_set(coord) &&
+           coord->unit_pos >
+           item_plugin_by_coord(coord)->b.nr_units(coord) - 1) {
+               return 0;
+       }
+       return 1;
+}
+#endif
+
+/* Adjust coordinate boundaries based on the number of items prior to coord_next/prev.
+   Returns 1 if the new position is does not exist. */
+static int coord_adjust_items(coord_t * coord, unsigned items, int is_next)
+{
+       /* If the node is invalid, leave it. */
+       if (coord->between == INVALID_COORD) {
+               return 1;
+       }
+
+       /* If the node is empty, set it appropriately. */
+       if (items == 0) {
+               coord->between = EMPTY_NODE;
+               coord_set_item_pos(coord, 0);
+               coord->unit_pos = 0;
+               return 1;
+       }
+
+       /* If it was empty and it no longer is, set to BEFORE/AFTER_ITEM. */
+       if (coord->between == EMPTY_NODE) {
+               coord->between = (is_next ? BEFORE_ITEM : AFTER_ITEM);
+               coord_set_item_pos(coord, 0);
+               coord->unit_pos = 0;
+               return 0;
+       }
+
+       /* If the item_pos is out-of-range, set it appropriatly. */
+       if (coord->item_pos >= items) {
+               coord->between = AFTER_ITEM;
+               coord_set_item_pos(coord, items - 1);
+               coord->unit_pos = 0;
+               /* If is_next, return 1 (can't go any further). */
+               return is_next;
+       }
+
+       return 0;
+}
+
+/* Advances the coordinate by one unit to the right.  If empty, no change.  If
+   coord_is_rightmost_unit, advances to AFTER THE LAST ITEM.  Returns 0 if new position is an
+   existing unit. */
+int coord_next_unit(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 1) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case BEFORE_UNIT:
+               /* Now it is positioned at the same unit. */
+               coord->between = AT_UNIT;
+               return 0;
+
+       case AFTER_UNIT:
+       case AT_UNIT:
+               /* If it was at or after a unit and there are more units in this item,
+                  advance to the next one. */
+               if (coord->unit_pos < coord_last_unit_pos(coord)) {
+                       coord->unit_pos += 1;
+                       coord->between = AT_UNIT;
+                       return 0;
+               }
+
+               /* Otherwise, it is crossing an item boundary and treated as if it was
+                  after the current item. */
+               coord->between = AFTER_ITEM;
+               coord->unit_pos = 0;
+               /* FALLTHROUGH */
+
+       case AFTER_ITEM:
+               /* Check for end-of-node. */
+               if (coord->item_pos == items - 1) {
+                       return 1;
+               }
+
+               coord_inc_item_pos(coord);
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+               return 0;
+
+       case BEFORE_ITEM:
+               /* The adjust_items checks ensure that we are valid here. */
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+               return 0;
+
+       case INVALID_COORD:
+       case EMPTY_NODE:
+               /* Handled in coord_adjust_items(). */
+               break;
+       }
+
+       impossible("jmacd-9902", "unreachable");
+       return 0;
+}
+
+/* Advances the coordinate by one item to the right.  If empty, no change.  If
+   coord_is_rightmost_unit, advances to AFTER THE LAST ITEM.  Returns 0 if new position is
+   an existing item. */
+int coord_next_item(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 1) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case AFTER_UNIT:
+       case AT_UNIT:
+       case BEFORE_UNIT:
+       case AFTER_ITEM:
+               /* Check for end-of-node. */
+               if (coord->item_pos == items - 1) {
+                       coord->between = AFTER_ITEM;
+                       coord->unit_pos = 0;
+                       coord_clear_iplug(coord);
+                       return 1;
+               }
+
+               /* Anywhere in an item, go to the next one. */
+               coord->between = AT_UNIT;
+               coord_inc_item_pos(coord);
+               coord->unit_pos = 0;
+               return 0;
+
+       case BEFORE_ITEM:
+               /* The out-of-range check ensures that we are valid here. */
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+               return 0;
+       case INVALID_COORD:
+       case EMPTY_NODE:
+               /* Handled in coord_adjust_items(). */
+               break;
+       }
+
+       impossible("jmacd-9903", "unreachable");
+       return 0;
+}
+
+/* Advances the coordinate by one unit to the left.  If empty, no change.  If
+   coord_is_leftmost_unit, advances to BEFORE THE FIRST ITEM.  Returns 0 if new position
+   is an existing unit. */
+int coord_prev_unit(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 0) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case AT_UNIT:
+       case BEFORE_UNIT:
+               if (coord->unit_pos > 0) {
+                       coord->unit_pos -= 1;
+                       coord->between = AT_UNIT;
+                       return 0;
+               }
+
+               if (coord->item_pos == 0) {
+                       coord->between = BEFORE_ITEM;
+                       return 1;
+               }
+
+               coord_dec_item_pos(coord);
+               coord->unit_pos = coord_last_unit_pos(coord);
+               coord->between = AT_UNIT;
+               return 0;
+
+       case AFTER_UNIT:
+               /* What if unit_pos is out-of-range? */
+               assert("jmacd-5442",
+                      coord->unit_pos <= coord_last_unit_pos(coord));
+               coord->between = AT_UNIT;
+               return 0;
+
+       case BEFORE_ITEM:
+               if (coord->item_pos == 0) {
+                       return 1;
+               }
+
+               coord_dec_item_pos(coord);
+               /* FALLTHROUGH */
+
+       case AFTER_ITEM:
+               coord->between = AT_UNIT;
+               coord->unit_pos = coord_last_unit_pos(coord);
+               return 0;
+
+       case INVALID_COORD:
+       case EMPTY_NODE:
+               break;
+       }
+
+       impossible("jmacd-9904", "unreachable");
+       return 0;
+}
+
+/* Advances the coordinate by one item to the left.  If empty, no change.  If
+   coord_is_leftmost_unit, advances to BEFORE THE FIRST ITEM.  Returns 0 if new position
+   is an existing item. */
+int coord_prev_item(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 0) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case AT_UNIT:
+       case AFTER_UNIT:
+       case BEFORE_UNIT:
+       case BEFORE_ITEM:
+
+               if (coord->item_pos == 0) {
+                       coord->between = BEFORE_ITEM;
+                       coord->unit_pos = 0;
+                       return 1;
+               }
+
+               coord_dec_item_pos(coord);
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+               return 0;
+
+       case AFTER_ITEM:
+               coord->between = AT_UNIT;
+               coord->unit_pos = 0;
+               return 0;
+
+       case INVALID_COORD:
+       case EMPTY_NODE:
+               break;
+       }
+
+       impossible("jmacd-9905", "unreachable");
+       return 0;
+}
+
+/* Calls either coord_init_first_unit or coord_init_last_unit depending on sideof argument. */
+void coord_init_sideof_unit(coord_t * coord, const znode * node, sideof dir)
+{
+       assert("jmacd-9821", dir == LEFT_SIDE || dir == RIGHT_SIDE);
+       if (dir == LEFT_SIDE) {
+               coord_init_first_unit(coord, node);
+       } else {
+               coord_init_last_unit(coord, node);
+       }
+}
+
+/* Calls either coord_is_before_leftmost or coord_is_after_rightmost depending on sideof
+   argument. */
+/* Audited by: green(2002.06.15) */
+int coord_is_after_sideof_unit(coord_t * coord, sideof dir)
+{
+       assert("jmacd-9822", dir == LEFT_SIDE || dir == RIGHT_SIDE);
+       if (dir == LEFT_SIDE) {
+               return coord_is_before_leftmost(coord);
+       } else {
+               return coord_is_after_rightmost(coord);
+       }
+}
+
+/* Calls either coord_next_unit or coord_prev_unit depending on sideof argument. */
+/* Audited by: green(2002.06.15) */
+int coord_sideof_unit(coord_t * coord, sideof dir)
+{
+       assert("jmacd-9823", dir == LEFT_SIDE || dir == RIGHT_SIDE);
+       if (dir == LEFT_SIDE) {
+               return coord_prev_unit(coord);
+       } else {
+               return coord_next_unit(coord);
+       }
+}
+
+#if REISER4_DEBUG
+int coords_equal(const coord_t * c1, const coord_t * c2)
+{
+       assert("nikita-2840", c1 != NULL);
+       assert("nikita-2841", c2 != NULL);
+
+       return
+           c1->node == c2->node &&
+           c1->item_pos == c2->item_pos &&
+           c1->unit_pos == c2->unit_pos && c1->between == c2->between;
+}
+#endif  /*  REISER4_DEBUG  */
+
+/* If coord_is_after_rightmost return NCOORD_ON_THE_RIGHT, if coord_is_after_leftmost
+   return NCOORD_ON_THE_LEFT, otherwise return NCOORD_INSIDE. */
+/* Audited by: green(2002.06.15) */
+coord_wrt_node coord_wrt(const coord_t * coord)
+{
+       if (coord_is_before_leftmost(coord)) {
+               return COORD_ON_THE_LEFT;
+       }
+
+       if (coord_is_after_rightmost(coord)) {
+               return COORD_ON_THE_RIGHT;
+       }
+
+       return COORD_INSIDE;
+}
+
+/* Returns true if the coordinate is positioned after the last item or after the last unit
+   of the last item or it is an empty node. */
+/* Audited by: green(2002.06.15) */
+int coord_is_after_rightmost(const coord_t * coord)
+{
+       assert("jmacd-7313", coord_check(coord));
+
+       switch (coord->between) {
+       case INVALID_COORD:
+       case AT_UNIT:
+       case BEFORE_UNIT:
+       case BEFORE_ITEM:
+               return 0;
+
+       case EMPTY_NODE:
+               return 1;
+
+       case AFTER_ITEM:
+               return (coord->item_pos == node_num_items(coord->node) - 1);
+
+       case AFTER_UNIT:
+               return ((coord->item_pos == node_num_items(coord->node) - 1) &&
+                       coord->unit_pos == coord_last_unit_pos(coord));
+       }
+
+       impossible("jmacd-9908", "unreachable");
+       return 0;
+}
+
+/* Returns true if the coordinate is positioned before the first item or it is an empty
+   node. */
+int coord_is_before_leftmost(const coord_t * coord)
+{
+       /* FIXME-VS: coord_check requires node to be loaded whereas it is not
+          necessary to check if coord is set before leftmost
+          assert ("jmacd-7313", coord_check (coord)); */
+       switch (coord->between) {
+       case INVALID_COORD:
+       case AT_UNIT:
+       case AFTER_ITEM:
+       case AFTER_UNIT:
+               return 0;
+
+       case EMPTY_NODE:
+               return 1;
+
+       case BEFORE_ITEM:
+       case BEFORE_UNIT:
+               return (coord->item_pos == 0) && (coord->unit_pos == 0);
+       }
+
+       impossible("jmacd-9908", "unreachable");
+       return 0;
+}
+
+/* Returns true if the coordinate is positioned after a item, before a item, after the
+   last unit of an item, before the first unit of an item, or at an empty node. */
+/* Audited by: green(2002.06.15) */
+int coord_is_between_items(const coord_t * coord)
+{
+       assert("jmacd-7313", coord_check(coord));
+
+       switch (coord->between) {
+       case INVALID_COORD:
+       case AT_UNIT:
+               return 0;
+
+       case AFTER_ITEM:
+       case BEFORE_ITEM:
+       case EMPTY_NODE:
+               return 1;
+
+       case BEFORE_UNIT:
+               return coord->unit_pos == 0;
+
+       case AFTER_UNIT:
+               return coord->unit_pos == coord_last_unit_pos(coord);
+       }
+
+       impossible("jmacd-9908", "unreachable");
+       return 0;
+}
+
+#if REISER4_DEBUG
+/* Returns true if the coordinates are positioned at adjacent units, regardless of
+   before-after or item boundaries. */
+int coord_are_neighbors(coord_t * c1, coord_t * c2)
+{
+       coord_t *left;
+       coord_t *right;
+
+       assert("nikita-1241", c1 != NULL);
+       assert("nikita-1242", c2 != NULL);
+       assert("nikita-1243", c1->node == c2->node);
+       assert("nikita-1244", coord_is_existing_unit(c1));
+       assert("nikita-1245", coord_is_existing_unit(c2));
+
+       left = right = NULL;
+       switch (coord_compare(c1, c2)) {
+       case COORD_CMP_ON_LEFT:
+               left = c1;
+               right = c2;
+               break;
+       case COORD_CMP_ON_RIGHT:
+               left = c2;
+               right = c1;
+               break;
+       case COORD_CMP_SAME:
+               return 0;
+       default:
+               wrong_return_value("nikita-1246", "compare_coords()");
+       }
+       assert("vs-731", left && right);
+       if (left->item_pos == right->item_pos) {
+               return left->unit_pos + 1 == right->unit_pos;
+       } else if (left->item_pos + 1 == right->item_pos) {
+               return (left->unit_pos == coord_last_unit_pos(left))
+                   && (right->unit_pos == 0);
+       } else {
+               return 0;
+       }
+}
+#endif  /*  REISER4_DEBUG  */
+
+/* Assuming two coordinates are positioned in the same node, return COORD_CMP_ON_RIGHT,
+   COORD_CMP_ON_LEFT, or COORD_CMP_SAME depending on c1's position relative to c2.  */
+/* Audited by: green(2002.06.15) */
+coord_cmp coord_compare(coord_t * c1, coord_t * c2)
+{
+       assert("vs-209", c1->node == c2->node);
+       assert("vs-194", coord_is_existing_unit(c1)
+              && coord_is_existing_unit(c2));
+
+       if (c1->item_pos > c2->item_pos)
+               return COORD_CMP_ON_RIGHT;
+       if (c1->item_pos < c2->item_pos)
+               return COORD_CMP_ON_LEFT;
+       if (c1->unit_pos > c2->unit_pos)
+               return COORD_CMP_ON_RIGHT;
+       if (c1->unit_pos < c2->unit_pos)
+               return COORD_CMP_ON_LEFT;
+       return COORD_CMP_SAME;
+}
+
+/* If the coordinate is between items, shifts it to the right.  Returns 0 on success and
+   non-zero if there is no position to the right. */
+int coord_set_to_right(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 1) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case AT_UNIT:
+               return 0;
+
+       case BEFORE_ITEM:
+       case BEFORE_UNIT:
+               coord->between = AT_UNIT;
+               return 0;
+
+       case AFTER_UNIT:
+               if (coord->unit_pos < coord_last_unit_pos(coord)) {
+                       coord->unit_pos += 1;
+                       coord->between = AT_UNIT;
+                       return 0;
+               } else {
+
+                       coord->unit_pos = 0;
+
+                       if (coord->item_pos == items - 1) {
+                               coord->between = AFTER_ITEM;
+                               return 1;
+                       }
+
+                       coord_inc_item_pos(coord);
+                       coord->between = AT_UNIT;
+                       return 0;
+               }
+
+       case AFTER_ITEM:
+               if (coord->item_pos == items - 1) {
+                       return 1;
+               }
+
+               coord_inc_item_pos(coord);
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+               return 0;
+
+       case EMPTY_NODE:
+               return 1;
+
+       case INVALID_COORD:
+               break;
+       }
+
+       impossible("jmacd-9920", "unreachable");
+       return 0;
+}
+
+/* If the coordinate is between items, shifts it to the left.  Returns 0 on success and
+   non-zero if there is no position to the left. */
+int coord_set_to_left(coord_t * coord)
+{
+       unsigned items = coord_num_items(coord);
+
+       if (coord_adjust_items(coord, items, 0) == 1) {
+               return 1;
+       }
+
+       switch (coord->between) {
+       case AT_UNIT:
+               return 0;
+
+       case AFTER_UNIT:
+               coord->between = AT_UNIT;
+               return 0;
+
+       case AFTER_ITEM:
+               coord->between = AT_UNIT;
+               coord->unit_pos = coord_last_unit_pos(coord);
+               return 0;
+
+       case BEFORE_UNIT:
+               if (coord->unit_pos > 0) {
+                       coord->unit_pos -= 1;
+                       coord->between = AT_UNIT;
+                       return 0;
+               } else {
+
+                       if (coord->item_pos == 0) {
+                               coord->between = BEFORE_ITEM;
+                               return 1;
+                       }
+
+                       coord->unit_pos = coord_last_unit_pos(coord);
+                       coord_dec_item_pos(coord);
+                       coord->between = AT_UNIT;
+                       return 0;
+               }
+
+       case BEFORE_ITEM:
+               if (coord->item_pos == 0) {
+                       return 1;
+               }
+
+               coord_dec_item_pos(coord);
+               coord->unit_pos = coord_last_unit_pos(coord);
+               coord->between = AT_UNIT;
+               return 0;
+
+       case EMPTY_NODE:
+               return 1;
+
+       case INVALID_COORD:
+               break;
+       }
+
+       impossible("jmacd-9920", "unreachable");
+       return 0;
+}
+
+static const char *coord_tween_tostring(between_enum n)
+{
+       switch (n) {
+       case BEFORE_UNIT:
+               return "before unit";
+       case BEFORE_ITEM:
+               return "before item";
+       case AT_UNIT:
+               return "at unit";
+       case AFTER_UNIT:
+               return "after unit";
+       case AFTER_ITEM:
+               return "after item";
+       case EMPTY_NODE:
+               return "empty node";
+       case INVALID_COORD:
+               return "invalid";
+       default:
+       {
+               static char buf[30];
+
+               sprintf(buf, "unknown: %i", n);
+               return buf;
+       }
+       }
+}
+
+void print_coord(const char *mes, const coord_t * coord, int node)
+{
+       if (coord == NULL) {
+               printk("%s: null\n", mes);
+               return;
+       }
+       printk("%s: item_pos = %d, unit_pos %d, tween=%s, iplug=%d\n",
+              mes, coord->item_pos, coord->unit_pos,
+              coord_tween_tostring(coord->between), coord->iplugid);
+}
+
+int
+item_utmost_child_real_block(const coord_t * coord, sideof side,
+                            reiser4_block_nr * blk)
+{
+       return item_plugin_by_coord(coord)->f.utmost_child_real_block(coord,
+                                                                     side,
+                                                                     blk);
+}
+
+int item_utmost_child(const coord_t * coord, sideof side, jnode ** child)
+{
+       return item_plugin_by_coord(coord)->f.utmost_child(coord, side, child);
+}
+
+/* @count bytes of flow @f got written, update correspondingly f->length,
+   f->data and f->key */
+void move_flow_forward(flow_t * f, unsigned count)
+{
+       if (f->data)
+               f->data += count;
+       f->length -= count;
+       set_key_offset(&f->key, get_key_offset(&f->key) + count);
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/coord.h linux-2.6.20/fs/reiser4/coord.h
--- linux-2.6.20.orig/fs/reiser4/coord.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/coord.h     2007-05-06 14:50:43.698975725 +0400
@@ -0,0 +1,389 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Coords */
+
+#if !defined( __REISER4_COORD_H__ )
+#define __REISER4_COORD_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+
+/* insertions happen between coords in the tree, so we need some means
+   of specifying the sense of betweenness. */
+typedef enum {
+       BEFORE_UNIT,            /* Note: we/init_coord depends on this value being zero. */
+       AT_UNIT,
+       AFTER_UNIT,
+       BEFORE_ITEM,
+       AFTER_ITEM,
+       INVALID_COORD,
+       EMPTY_NODE,
+} between_enum;
+
+/* location of coord w.r.t. its node */
+typedef enum {
+       COORD_ON_THE_LEFT = -1,
+       COORD_ON_THE_RIGHT = +1,
+       COORD_INSIDE = 0
+} coord_wrt_node;
+
+typedef enum {
+       COORD_CMP_SAME = 0, COORD_CMP_ON_LEFT = -1, COORD_CMP_ON_RIGHT = +1
+} coord_cmp;
+
+struct coord {
+       /* node in a tree */
+       /*  0 */ znode *node;
+
+       /* position of item within node */
+       /*  4 */ pos_in_node_t item_pos;
+       /* position of unit within item */
+       /*  6 */ pos_in_node_t unit_pos;
+       /* optimization: plugin of item is stored in coord_t. Until this was
+          implemented, item_plugin_by_coord() was major CPU consumer. ->iplugid
+          is invalidated (set to 0xff) on each modification of ->item_pos,
+          and all such modifications are funneled through coord_*_item_pos()
+          functions below.
+        */
+       /*  8 */ char iplugid;
+       /* position of coord w.r.t. to neighboring items and/or units.
+          Values are taken from &between_enum above.
+        */
+       /*  9 */ char between;
+       /* padding. It will be added by the compiler anyway to conform to the
+        * C language alignment requirements. We keep it here to be on the
+        * safe side and to have a clear picture of the memory layout of this
+        * structure. */
+       /* 10 */ __u16 pad;
+       /* 12 */ int offset;
+#if REISER4_DEBUG
+       unsigned long plug_v;
+       unsigned long body_v;
+#endif
+};
+
+#define INVALID_PLUGID  ((char)((1 << 8) - 1))
+#define INVALID_OFFSET -1
+
+static inline void coord_clear_iplug(coord_t * coord)
+{
+       assert("nikita-2835", coord != NULL);
+       coord->iplugid = INVALID_PLUGID;
+       coord->offset = INVALID_OFFSET;
+}
+
+static inline int coord_is_iplug_set(const coord_t * coord)
+{
+       assert("nikita-2836", coord != NULL);
+       return coord->iplugid != INVALID_PLUGID;
+}
+
+static inline void coord_set_item_pos(coord_t * coord, pos_in_node_t pos)
+{
+       assert("nikita-2478", coord != NULL);
+       coord->item_pos = pos;
+       coord_clear_iplug(coord);
+}
+
+static inline void coord_dec_item_pos(coord_t * coord)
+{
+       assert("nikita-2480", coord != NULL);
+       --coord->item_pos;
+       coord_clear_iplug(coord);
+}
+
+static inline void coord_inc_item_pos(coord_t * coord)
+{
+       assert("nikita-2481", coord != NULL);
+       ++coord->item_pos;
+       coord_clear_iplug(coord);
+}
+
+static inline void coord_add_item_pos(coord_t * coord, int delta)
+{
+       assert("nikita-2482", coord != NULL);
+       coord->item_pos += delta;
+       coord_clear_iplug(coord);
+}
+
+static inline void coord_invalid_item_pos(coord_t * coord)
+{
+       assert("nikita-2832", coord != NULL);
+       coord->item_pos = (unsigned short)~0;
+       coord_clear_iplug(coord);
+}
+
+/* Reverse a direction. */
+static inline sideof sideof_reverse(sideof side)
+{
+       return side == LEFT_SIDE ? RIGHT_SIDE : LEFT_SIDE;
+}
+
+/* NOTE: There is a somewhat odd mixture of the following opposed terms:
+
+   "first" and "last"
+   "next" and "prev"
+   "before" and "after"
+   "leftmost" and "rightmost"
+
+   But I think the chosen names are decent the way they are.
+*/
+
+/* COORD INITIALIZERS */
+
+/* Initialize an invalid coordinate. */
+extern void coord_init_invalid(coord_t * coord, const znode * node);
+
+extern void coord_init_first_unit_nocheck(coord_t * coord, const znode * node);
+
+/* Initialize a coordinate to point at the first unit of the first item.  If the node is
+   empty, it is positioned at the EMPTY_NODE. */
+extern void coord_init_first_unit(coord_t * coord, const znode * node);
+
+/* Initialize a coordinate to point at the last unit of the last item.  If the node is
+   empty, it is positioned at the EMPTY_NODE. */
+extern void coord_init_last_unit(coord_t * coord, const znode * node);
+
+/* Initialize a coordinate to before the first item.  If the node is empty, it is
+   positioned at the EMPTY_NODE. */
+extern void coord_init_before_first_item(coord_t * coord, const znode * node);
+
+/* Initialize a coordinate to after the last item.  If the node is empty, it is positioned
+   at the EMPTY_NODE. */
+extern void coord_init_after_last_item(coord_t * coord, const znode * node);
+
+/* Initialize a coordinate to after last unit in the item. Coord must be set
+   already to existing item */
+void coord_init_after_item_end(coord_t * coord);
+
+/* Initialize a coordinate to before the item. Coord must be set already to existing item */
+void coord_init_before_item(coord_t *);
+/* Initialize a coordinate to after the item. Coord must be set already to existing item */
+void coord_init_after_item(coord_t *);
+
+/* Calls either coord_init_first_unit or coord_init_last_unit depending on sideof argument. */
+extern void coord_init_sideof_unit(coord_t * coord, const znode * node,
+                                  sideof dir);
+
+/* Initialize a coordinate by 0s. Used in places where init_coord was used and
+   it was not clear how actually
+   FIXME-VS: added by vs (2002, june, 8) */
+extern void coord_init_zero(coord_t * coord);
+
+/* COORD METHODS */
+
+/* after shifting of node content, coord previously set properly may become
+   invalid, try to "normalize" it. */
+void coord_normalize(coord_t * coord);
+
+/* Copy a coordinate. */
+extern void coord_dup(coord_t * coord, const coord_t * old_coord);
+
+/* Copy a coordinate without check. */
+void coord_dup_nocheck(coord_t * coord, const coord_t * old_coord);
+
+unsigned coord_num_units(const coord_t * coord);
+
+/* Return the last valid unit number at the present item (i.e.,
+   coord_num_units() - 1). */
+static inline unsigned coord_last_unit_pos(const coord_t * coord)
+{
+       return coord_num_units(coord) - 1;
+}
+
+#if REISER4_DEBUG
+/* For assertions only, checks for a valid coordinate. */
+extern int coord_check(const coord_t * coord);
+
+extern unsigned long znode_times_locked(const znode * z);
+
+static inline void coord_update_v(coord_t * coord)
+{
+       coord->plug_v = coord->body_v = znode_times_locked(coord->node);
+}
+#endif
+
+extern int coords_equal(const coord_t * c1, const coord_t * c2);
+
+extern void print_coord(const char *mes, const coord_t * coord, int print_node);
+
+/* If coord_is_after_rightmost return NCOORD_ON_THE_RIGHT, if coord_is_after_leftmost
+   return NCOORD_ON_THE_LEFT, otherwise return NCOORD_INSIDE. */
+extern coord_wrt_node coord_wrt(const coord_t * coord);
+
+/* Returns true if the coordinates are positioned at adjacent units, regardless of
+   before-after or item boundaries. */
+extern int coord_are_neighbors(coord_t * c1, coord_t * c2);
+
+/* Assuming two coordinates are positioned in the same node, return NCOORD_CMP_ON_RIGHT,
+   NCOORD_CMP_ON_LEFT, or NCOORD_CMP_SAME depending on c1's position relative to c2.  */
+extern coord_cmp coord_compare(coord_t * c1, coord_t * c2);
+
+/* COORD PREDICATES */
+
+/* Returns true if the coord was initializewd by coord_init_invalid (). */
+extern int coord_is_invalid(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned at an existing item, not before or after
+   an item.  It may be placed at, before, or after any unit within the item, whether
+   existing or not.  If this is true you can call methods of the item plugin.  */
+extern int coord_is_existing_item(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned after a item, before a item, after the
+   last unit of an item, before the first unit of an item, or at an empty node. */
+extern int coord_is_between_items(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned at an existing unit, not before or after a
+   unit. */
+extern int coord_is_existing_unit(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned at an empty node. */
+extern int coord_is_empty(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned at the first unit of the first item.  Not
+   true for empty nodes nor coordinates positioned before the first item. */
+extern int coord_is_leftmost_unit(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned after the last item or after the last unit
+   of the last item or it is an empty node. */
+extern int coord_is_after_rightmost(const coord_t * coord);
+
+/* Returns true if the coordinate is positioned before the first item or it is an empty
+   node. */
+extern int coord_is_before_leftmost(const coord_t * coord);
+
+/* Calls either coord_is_before_leftmost or coord_is_after_rightmost depending on sideof
+   argument. */
+extern int coord_is_after_sideof_unit(coord_t * coord, sideof dir);
+
+/* COORD MODIFIERS */
+
+/* Advances the coordinate by one unit to the right.  If empty, no change.  If
+   coord_is_rightmost_unit, advances to AFTER THE LAST ITEM.  Returns 0 if new position is
+   an existing unit. */
+extern int coord_next_unit(coord_t * coord);
+
+/* Advances the coordinate by one item to the right.  If empty, no change.  If
+   coord_is_rightmost_unit, advances to AFTER THE LAST ITEM.  Returns 0 if new position is
+   an existing item. */
+extern int coord_next_item(coord_t * coord);
+
+/* Advances the coordinate by one unit to the left.  If empty, no change.  If
+   coord_is_leftmost_unit, advances to BEFORE THE FIRST ITEM.  Returns 0 if new position
+   is an existing unit. */
+extern int coord_prev_unit(coord_t * coord);
+
+/* Advances the coordinate by one item to the left.  If empty, no change.  If
+   coord_is_leftmost_unit, advances to BEFORE THE FIRST ITEM.  Returns 0 if new position
+   is an existing item. */
+extern int coord_prev_item(coord_t * coord);
+
+/* If the coordinate is between items, shifts it to the right.  Returns 0 on success and
+   non-zero if there is no position to the right. */
+extern int coord_set_to_right(coord_t * coord);
+
+/* If the coordinate is between items, shifts it to the left.  Returns 0 on success and
+   non-zero if there is no position to the left. */
+extern int coord_set_to_left(coord_t * coord);
+
+/* If the coordinate is at an existing unit, set to after that unit.  Returns 0 on success
+   and non-zero if the unit did not exist. */
+extern int coord_set_after_unit(coord_t * coord);
+
+/* Calls either coord_next_unit or coord_prev_unit depending on sideof argument. */
+extern int coord_sideof_unit(coord_t * coord, sideof dir);
+
+/* iterate over all units in @node */
+#define for_all_units( coord, node )                                   \
+       for( coord_init_before_first_item( ( coord ), ( node ) ) ;      \
+            coord_next_unit( coord ) == 0 ; )
+
+/* iterate over all items in @node */
+#define for_all_items( coord, node )                                   \
+       for( coord_init_before_first_item( ( coord ), ( node ) ) ;      \
+            coord_next_item( coord ) == 0 ; )
+
+/* COORD/ITEM METHODS */
+
+extern int item_utmost_child_real_block(const coord_t * coord, sideof side,
+                                       reiser4_block_nr * blk);
+extern int item_utmost_child(const coord_t * coord, sideof side,
+                            jnode ** child);
+
+/* a flow is a sequence of bytes being written to or read from the tree.  The
+   tree will slice the flow into items while storing it into nodes, but all of
+   that is hidden from anything outside the tree.  */
+
+struct flow {
+       reiser4_key key;        /* key of start of flow's sequence of bytes */
+       loff_t length;          /* length of flow's sequence of bytes */
+       char *data;             /* start of flow's sequence of bytes */
+       int user;               /* if 1 data is user space, 0 - kernel space */
+       rw_op op;               /* NIKITA-FIXME-HANS: comment is where?  */
+};
+
+void move_flow_forward(flow_t * f, unsigned count);
+
+/* &reiser4_item_data - description of data to be inserted or pasted
+
+   Q: articulate the reasons for the difference between this and flow.
+
+   A: Becides flow we insert into tree other things: stat data, directory
+   entry, etc.  To insert them into tree one has to provide this structure. If
+   one is going to insert flow - he can use insert_flow, where this structure
+   does not have to be created
+*/
+struct reiser4_item_data {
+       /* actual data to be inserted. If NULL, ->create_item() will not
+          do xmemcpy itself, leaving this up to the caller. This can
+          save some amount of unnecessary memory copying, for example,
+          during insertion of stat data.
+
+        */
+       char *data;
+       /* 1 if 'char * data' contains pointer to user space and 0 if it is
+          kernel space */
+       int user;
+       /* amount of data we are going to insert or paste */
+       int length;
+       /* "Arg" is opaque data that is passed down to the
+          ->create_item() method of node layout, which in turn
+          hands it to the ->create_hook() of item being created. This
+          arg is currently used by:
+
+          .  ->create_hook() of internal item
+          (fs/reiser4/plugin/item/internal.c:internal_create_hook()),
+          . ->paste() method of directory item.
+          . ->create_hook() of extent item
+
+          For internal item, this is left "brother" of new node being
+          inserted and it is used to add new node into sibling list
+          after parent to it was just inserted into parent.
+
+          While ->arg does look somewhat of unnecessary compication,
+          it actually saves a lot of headache in many places, because
+          all data necessary to insert or paste new data into tree are
+          collected in one place, and this eliminates a lot of extra
+          argument passing and storing everywhere.
+
+        */
+       void *arg;
+       /* plugin of item we are inserting */
+       item_plugin *iplug;
+};
+
+/* __REISER4_COORD_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/debug.c linux-2.6.20/fs/reiser4/debug.c
--- linux-2.6.20.orig/fs/reiser4/debug.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/debug.c     2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,308 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Debugging facilities. */
+
+/*
+ * This file contains generic debugging functions used by reiser4. Roughly
+ * following:
+ *
+ *     panicking: reiser4_do_panic(), reiser4_print_prefix().
+ *
+ *     locking:
+ *     reiser4_schedulable(), reiser4_lock_counters(), print_lock_counters(),
+ *     reiser4_no_counters_are_held(), reiser4_commit_check_locks()
+ *
+ *     error code monitoring (see comment before RETERR macro):
+ *     reiser4_return_err(), reiser4_report_err().
+ *
+ *     stack back-tracing: fill_backtrace()
+ *
+ *     miscellaneous: reiser4_preempt_point(), call_on_each_assert(),
+ *     reiser4_debugtrap().
+ *
+ */
+
+#include "reiser4.h"
+#include "context.h"
+#include "super.h"
+#include "txnmgr.h"
+#include "znode.h"
+
+#include <linux/sysfs.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/spinlock.h>
+#include <linux/kallsyms.h>
+#include <linux/vmalloc.h>
+#include <linux/ctype.h>
+#include <linux/sysctl.h>
+#include <linux/hardirq.h>
+
+#if 0
+#if REISER4_DEBUG
+static void reiser4_report_err(void);
+#else
+#define reiser4_report_err() noop
+#endif
+#endif  /*  0  */
+
+/*
+ * global buffer where message given to reiser4_panic is formatted.
+ */
+static char panic_buf[REISER4_PANIC_MSG_BUFFER_SIZE];
+
+/*
+ * lock protecting consistency of panic_buf under concurrent panics
+ */
+static DEFINE_SPINLOCK(panic_guard);
+
+/* Your best friend. Call it on each occasion.  This is called by
+    fs/reiser4/debug.h:reiser4_panic(). */
+void reiser4_do_panic(const char *format /* format string */ , ... /* rest */ )
+{
+       static int in_panic = 0;
+       va_list args;
+
+       /*
+        * check for recursive panic.
+        */
+       if (in_panic == 0) {
+               in_panic = 1;
+
+               spin_lock(&panic_guard);
+               va_start(args, format);
+               vsnprintf(panic_buf, sizeof(panic_buf), format, args);
+               va_end(args);
+               printk(KERN_EMERG "reiser4 panicked cowardly: %s", panic_buf);
+               spin_unlock(&panic_guard);
+
+               /*
+                * if kernel debugger is configured---drop in. Early dropping
+                * into kgdb is not always convenient, because panic message
+                * is not yet printed most of the times. But:
+                *
+                *     (1) message can be extracted from printk_buf[]
+                *     (declared static inside of printk()), and
+                *
+                *     (2) sometimes serial/kgdb combo dies while printing
+                *     long panic message, so it's more prudent to break into
+                *     debugger earlier.
+                *
+                */
+               DEBUGON(1);
+       }
+       /* to make gcc happy about noreturn attribute */
+       panic("%s", panic_buf);
+}
+
+#if 0
+void
+reiser4_print_prefix(const char *level, int reperr, const char *mid,
+                    const char *function, const char *file, int lineno)
+{
+       const char *comm;
+       int pid;
+
+       if (unlikely(in_interrupt() || in_irq())) {
+               comm = "interrupt";
+               pid = 0;
+       } else {
+               comm = current->comm;
+               pid = current->pid;
+       }
+       printk("%sreiser4[%.16s(%i)]: %s (%s:%i)[%s]:\n",
+              level, comm, pid, function, file, lineno, mid);
+       if (reperr)
+               reiser4_report_err();
+}
+#endif  /*  0  */
+
+/* Preemption point: this should be called periodically during long running
+   operations (carry, allocate, and squeeze are best examples) */
+int reiser4_preempt_point(void)
+{
+       assert("nikita-3008", reiser4_schedulable());
+       cond_resched();
+       return signal_pending(current);
+}
+
+#if REISER4_DEBUG
+/* Debugging aid: return struct where information about locks taken by current
+   thread is accumulated. This can be used to formulate lock ordering
+   constraints and various assertions.
+
+*/
+reiser4_lock_counters_info *reiser4_lock_counters(void)
+{
+       reiser4_context *ctx = get_current_context();
+       assert("jmacd-1123", ctx != NULL);
+       return &ctx->locks;
+}
+
+/*
+ * print human readable information about locks held by the reiser4 context.
+ */
+static void print_lock_counters(const char *prefix,
+                               const reiser4_lock_counters_info * info)
+{
+       printk("%s: jnode: %i, tree: %i (r:%i,w:%i), dk: %i (r:%i,w:%i)\n"
+              "jload: %i, "
+              "txnh: %i, atom: %i, stack: %i, txnmgr: %i, "
+              "ktxnmgrd: %i, fq: %i\n"
+              "inode: %i, "
+              "cbk_cache: %i (r:%i,w%i), "
+              "eflush: %i, "
+              "zlock: %i,\n"
+              "spin: %i, long: %i inode_sem: (r:%i,w:%i)\n"
+              "d: %i, x: %i, t: %i\n", prefix,
+              info->spin_locked_jnode,
+              info->rw_locked_tree, info->read_locked_tree,
+              info->write_locked_tree,
+              info->rw_locked_dk, info->read_locked_dk, info->write_locked_dk,
+              info->spin_locked_jload,
+              info->spin_locked_txnh,
+              info->spin_locked_atom, info->spin_locked_stack,
+              info->spin_locked_txnmgr, info->spin_locked_ktxnmgrd,
+              info->spin_locked_fq,
+              info->spin_locked_inode,
+              info->rw_locked_cbk_cache,
+              info->read_locked_cbk_cache,
+              info->write_locked_cbk_cache,
+              info->spin_locked_super_eflush,
+              info->spin_locked_zlock,
+              info->spin_locked,
+              info->long_term_locked_znode,
+              info->inode_sem_r, info->inode_sem_w,
+              info->d_refs, info->x_refs, info->t_refs);
+}
+
+/* check that no spinlocks are held */
+int reiser4_schedulable(void)
+{
+       if (get_current_context_check() != NULL) {
+               if (!LOCK_CNT_NIL(spin_locked)) {
+                       print_lock_counters("in atomic", reiser4_lock_counters());
+                       return 0;
+               }
+       }
+       might_sleep();
+       return 1;
+}
+/*
+ * return true, iff no locks are held.
+ */
+int reiser4_no_counters_are_held(void)
+{
+       reiser4_lock_counters_info *counters;
+
+       counters = reiser4_lock_counters();
+       return
+           (counters->spin_locked_zlock == 0) &&
+           (counters->spin_locked_jnode == 0) &&
+           (counters->rw_locked_tree == 0) &&
+           (counters->read_locked_tree == 0) &&
+           (counters->write_locked_tree == 0) &&
+           (counters->rw_locked_dk == 0) &&
+           (counters->read_locked_dk == 0) &&
+           (counters->write_locked_dk == 0) &&
+           (counters->spin_locked_txnh == 0) &&
+           (counters->spin_locked_atom == 0) &&
+           (counters->spin_locked_stack == 0) &&
+           (counters->spin_locked_txnmgr == 0) &&
+           (counters->spin_locked_inode == 0) &&
+           (counters->spin_locked == 0) &&
+           (counters->long_term_locked_znode == 0) &&
+           (counters->inode_sem_r == 0) &&
+           (counters->inode_sem_w == 0) && (counters->d_refs == 0);
+}
+
+/*
+ * return true, iff transaction commit can be done under locks held by the
+ * current thread.
+ */
+int reiser4_commit_check_locks(void)
+{
+       reiser4_lock_counters_info *counters;
+       int inode_sem_r;
+       int inode_sem_w;
+       int result;
+
+       /*
+        * inode's read/write semaphore is the only reiser4 lock that can be
+        * held during commit.
+        */
+
+       counters = reiser4_lock_counters();
+       inode_sem_r = counters->inode_sem_r;
+       inode_sem_w = counters->inode_sem_w;
+
+       counters->inode_sem_r = counters->inode_sem_w = 0;
+       result = reiser4_no_counters_are_held();
+       counters->inode_sem_r = inode_sem_r;
+       counters->inode_sem_w = inode_sem_w;
+       return result;
+}
+
+/*
+ * fill "error site" in the current reiser4 context. See comment before RETERR
+ * macro for more details.
+ */
+void reiser4_return_err(int code, const char *file, int line)
+{
+       if (code < 0 && is_in_reiser4_context()) {
+               reiser4_context *ctx = get_current_context();
+
+               if (ctx != NULL) {
+                       ctx->err.code = code;
+                       ctx->err.file = file;
+                       ctx->err.line = line;
+               }
+       }
+}
+
+#if 0
+/*
+ * report error information recorder by reiser4_return_err().
+ */
+static void reiser4_report_err(void)
+{
+       reiser4_context *ctx = get_current_context_check();
+
+       if (ctx != NULL) {
+               if (ctx->err.code != 0) {
+                       printk("code: %i at %s:%i\n",
+                              ctx->err.code, ctx->err.file, ctx->err.line);
+               }
+       }
+}
+#endif  /*  0  */
+
+#endif                         /* REISER4_DEBUG */
+
+#if KERNEL_DEBUGGER
+
+/*
+ * this functions just drops into kernel debugger. It is a convenient place to
+ * put breakpoint in.
+ */
+void reiser4_debugtrap(void)
+{
+       /* do nothing. Put break point here. */
+#if defined(CONFIG_KGDB) && !defined(CONFIG_REISER4_FS_MODULE)
+       extern void breakpoint(void);
+       breakpoint();
+#endif
+}
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/debug.h linux-2.6.20/fs/reiser4/debug.h
--- linux-2.6.20.orig/fs/reiser4/debug.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/debug.h     2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,350 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Declarations of debug macros. */
+
+#if !defined( __FS_REISER4_DEBUG_H__ )
+#define __FS_REISER4_DEBUG_H__
+
+#include "forward.h"
+#include "reiser4.h"
+
+/* generic function to produce formatted output, decorating it with
+   whatever standard prefixes/postfixes we want. "Fun" is a function
+   that will be actually called, can be printk, panic etc.
+   This is for use by other debugging macros, not by users. */
+#define DCALL(lev, fun, reperr, label, format, ...)                    \
+({                                                                     \
+       fun(lev "reiser4[%.16s(%i)]: %s (%s:%i)[%s]:\n" format "\n" ,   \
+           current->comm, current->pid, __FUNCTION__,                  \
+           __FILE__, __LINE__, label, ## __VA_ARGS__);                 \
+})
+
+/*
+ * cause kernel to crash
+ */
+#define reiser4_panic(mid, format, ...)                                \
+       DCALL("", reiser4_do_panic, 1, mid, format , ## __VA_ARGS__)
+
+/* print message with indication of current process, file, line and
+   function */
+#define reiser4_log(label, format, ...)                                \
+       DCALL(KERN_DEBUG, printk, 0, label, format , ## __VA_ARGS__)
+
+/* Assertion checked during compilation.
+    If "cond" is false (0) we get duplicate case label in switch.
+    Use this to check something like famous
+       cassert (sizeof(struct reiserfs_journal_commit) == 4096) ;
+    in 3.x journal.c. If cassertion fails you get compiler error,
+    so no "maintainer-id".
+*/
+#define cassert(cond) ({ switch(-1) { case (cond): case 0: break; } })
+
+#define noop   do {;} while(0)
+
+#if REISER4_DEBUG
+/* version of info that only actually prints anything when _d_ebugging
+    is on */
+#define dinfo(format, ...) printk(format , ## __VA_ARGS__)
+/* macro to catch logical errors. Put it into `default' clause of
+    switch() statement. */
+#define impossible(label, format, ...)                         \
+         reiser4_panic(label, "impossible: " format , ## __VA_ARGS__)
+/* assert assures that @cond is true. If it is not, reiser4_panic() is
+   called. Use this for checking logical consistency and _never_ call
+   this to check correctness of external data: disk blocks and user-input . */
+#define assert(label, cond)                                                    \
+({                                                                             \
+       /* call_on_each_assert(); */                                            \
+       if (cond) {                                                             \
+               /* put negated check to avoid using !(cond) that would lose     \
+                * warnings for things like assert(a = b); */                   \
+               ;                                                               \
+       } else {                                                                \
+               DEBUGON(1);                                                     \
+               reiser4_panic(label, "assertion failed: %s", #cond);            \
+       }                                                                       \
+})
+
+/* like assertion, but @expr is evaluated even if REISER4_DEBUG is off. */
+#define check_me( label, expr )        assert( label, ( expr ) )
+
+#define ON_DEBUG( exp ) exp
+
+extern int reiser4_schedulable(void);
+extern void call_on_each_assert(void);
+
+#else
+
+#define dinfo( format, args... ) noop
+#define impossible( label, format, args... ) noop
+#define assert( label, cond ) noop
+#define check_me( label, expr )        ( ( void ) ( expr ) )
+#define ON_DEBUG( exp )
+#define reiser4_schedulable() might_sleep()
+
+/* REISER4_DEBUG */
+#endif
+
+#if REISER4_DEBUG
+/* per-thread information about lock acquired by this thread. Used by lock
+ * ordering checking in spin_macros.h */
+typedef struct reiser4_lock_counters_info {
+       int rw_locked_tree;
+       int read_locked_tree;
+       int write_locked_tree;
+
+       int rw_locked_dk;
+       int read_locked_dk;
+       int write_locked_dk;
+
+       int rw_locked_cbk_cache;
+       int read_locked_cbk_cache;
+       int write_locked_cbk_cache;
+
+       int spin_locked_zlock;
+       int spin_locked_jnode;
+       int spin_locked_jload;
+       int spin_locked_txnh;
+       int spin_locked_atom;
+       int spin_locked_stack;
+       int spin_locked_txnmgr;
+       int spin_locked_ktxnmgrd;
+       int spin_locked_fq;
+       int spin_locked_inode;
+       int spin_locked_super_eflush;
+       int spin_locked;
+       int long_term_locked_znode;
+
+       int inode_sem_r;
+       int inode_sem_w;
+
+       int d_refs;
+       int x_refs;
+       int t_refs;
+} reiser4_lock_counters_info;
+
+extern reiser4_lock_counters_info *reiser4_lock_counters(void);
+#define IN_CONTEXT(a, b) (is_in_reiser4_context() ? (a) : (b))
+
+/* increment lock-counter @counter, if present */
+#define LOCK_CNT_INC(counter)                                  \
+       IN_CONTEXT(++(reiser4_lock_counters()->counter), 0)
+
+/* decrement lock-counter @counter, if present */
+#define LOCK_CNT_DEC(counter)                                  \
+       IN_CONTEXT(--(reiser4_lock_counters()->counter), 0)
+
+/* check that lock-counter is zero. This is for use in assertions */
+#define LOCK_CNT_NIL(counter)                                  \
+       IN_CONTEXT(reiser4_lock_counters()->counter == 0, 1)
+
+/* check that lock-counter is greater than zero. This is for use in
+ * assertions */
+#define LOCK_CNT_GTZ(counter)                                  \
+       IN_CONTEXT(reiser4_lock_counters()->counter > 0, 1)
+#define LOCK_CNT_LT(counter,n)                                 \
+       IN_CONTEXT(reiser4_lock_counters()->counter < n, 1)
+
+#else                          /* REISER4_DEBUG */
+
+/* no-op versions on the above */
+
+typedef struct reiser4_lock_counters_info {
+} reiser4_lock_counters_info;
+
+#define reiser4_lock_counters() ((reiser4_lock_counters_info *)NULL)
+#define LOCK_CNT_INC(counter) noop
+#define LOCK_CNT_DEC(counter) noop
+#define LOCK_CNT_NIL(counter) (1)
+#define LOCK_CNT_GTZ(counter) (1)
+#define LOCK_CNT_LT(counter,n) (1)
+
+#endif                         /* REISER4_DEBUG */
+
+#define assert_spin_not_locked(lock) BUG_ON(0)
+#define assert_rw_write_locked(lock) BUG_ON(0)
+#define assert_rw_read_locked(lock) BUG_ON(0)
+#define assert_rw_locked(lock) BUG_ON(0)
+#define assert_rw_not_write_locked(lock) BUG_ON(0)
+#define assert_rw_not_read_locked(lock) BUG_ON(0)
+#define assert_rw_not_locked(lock) BUG_ON(0)
+
+/* flags controlling debugging behavior. Are set through debug_flags=N mount
+   option. */
+typedef enum {
+       /* print a lot of information during panic. When this is on all jnodes
+        * are listed. This can be *very* large output. Usually you don't want
+        * this. Especially over serial line. */
+       REISER4_VERBOSE_PANIC = 0x00000001,
+       /* print a lot of information during umount */
+       REISER4_VERBOSE_UMOUNT = 0x00000002,
+       /* print gathered statistics on umount */
+       REISER4_STATS_ON_UMOUNT = 0x00000004,
+       /* check node consistency */
+       REISER4_CHECK_NODE = 0x00000008
+} reiser4_debug_flags;
+
+extern int is_in_reiser4_context(void);
+
+/*
+ * evaluate expression @e only if with reiser4 context
+ */
+#define ON_CONTEXT(e)  do {                    \
+       if(is_in_reiser4_context()) {           \
+               e;                              \
+       } } while(0)
+
+/*
+ * evaluate expression @e only when within reiser4_context and debugging is
+ * on.
+ */
+#define ON_DEBUG_CONTEXT( e ) ON_DEBUG( ON_CONTEXT( e ) )
+
+/*
+ * complain about unexpected function result and crash. Used in "default"
+ * branches of switch statements and alike to assert that invalid results are
+ * not silently ignored.
+ */
+#define wrong_return_value( label, function )                          \
+       impossible( label, "wrong return value from " function )
+
+/* Issue different types of reiser4 messages to the console */
+#define warning( label, format, ... )                                  \
+       DCALL( KERN_WARNING,                                            \
+              printk, 1, label, "WARNING: " format , ## __VA_ARGS__ )
+#define notice( label, format, ... )                                   \
+       DCALL( KERN_NOTICE,                                             \
+              printk, 1, label, "NOTICE: " format , ## __VA_ARGS__ )
+
+/* mark not yet implemented functionality */
+#define not_yet( label, format, ... )                          \
+       reiser4_panic( label, "NOT YET IMPLEMENTED: " format , ## __VA_ARGS__ )
+
+extern void reiser4_do_panic(const char *format, ...)
+    __attribute__ ((noreturn, format(printf, 1, 2)));
+
+extern int reiser4_preempt_point(void);
+extern void reiser4_print_stats(void);
+
+#if REISER4_DEBUG
+extern int reiser4_no_counters_are_held(void);
+extern int reiser4_commit_check_locks(void);
+#else
+#define reiser4_no_counters_are_held() (1)
+#define reiser4_commit_check_locks() (1)
+#endif
+
+/* true if @i is power-of-two. Useful for rate-limited warnings, etc. */
+#define IS_POW(i)                              \
+({                                             \
+       typeof(i) __i;                          \
+                                               \
+       __i = (i);                              \
+       !(__i & (__i - 1));                     \
+})
+
+#define KERNEL_DEBUGGER (1)
+
+#if KERNEL_DEBUGGER
+
+extern void reiser4_debugtrap(void);
+
+/*
+ * Check condition @cond and drop into kernel debugger (kgdb) if it's true. If
+ * kgdb is not compiled in, do nothing.
+ */
+#define DEBUGON(cond)                                  \
+({                                                     \
+       if (unlikely(cond))                             \
+               reiser4_debugtrap();                    \
+})
+#else
+#define DEBUGON(cond) noop
+#endif
+
+/*
+ * Error code tracing facility. (Idea is borrowed from XFS code.)
+ *
+ * Suppose some strange and/or unexpected code is returned from some function
+ * (for example, write(2) returns -EEXIST). It is possible to place a
+ * breakpoint in the reiser4_write(), but it is too late here. How to find out
+ * in what particular place -EEXIST was generated first?
+ *
+ * In reiser4 all places where actual error codes are produced (that is,
+ * statements of the form
+ *
+ *     return -EFOO;        // (1), or
+ *
+ *     result = -EFOO;      // (2)
+ *
+ * are replaced with
+ *
+ *     return RETERR(-EFOO);        // (1a), and
+ *
+ *     result = RETERR(-EFOO);      // (2a) respectively
+ *
+ * RETERR() macro fills a backtrace in reiser4_context. This back-trace is
+ * printed in error and warning messages. Moreover, it's possible to put a
+ * conditional breakpoint in reiser4_return_err (low-level function called
+ * by RETERR() to do the actual work) to break into debugger immediately
+ * when particular error happens.
+ *
+ */
+
+#if REISER4_DEBUG
+
+/*
+ * data-type to store information about where error happened ("error site").
+ */
+typedef struct err_site {
+       int code;               /* error code */
+       const char *file;       /* source file, filled by __FILE__ */
+       int line;               /* source file line, filled by __LINE__ */
+} err_site;
+
+extern void reiser4_return_err(int code, const char *file, int line);
+
+/*
+ * fill &get_current_context()->err_site with error information.
+ */
+#define RETERR(code)                                   \
+({                                                     \
+       typeof(code) __code;                            \
+                                                       \
+       __code = (code);                                \
+       reiser4_return_err(__code, __FILE__, __LINE__); \
+       __code;                                         \
+})
+
+#else
+
+/*
+ * no-op versions of the above
+ */
+
+typedef struct err_site {
+} err_site;
+#define RETERR(code) code
+#endif
+
+#if REISER4_LARGE_KEY
+/*
+ * conditionally compile arguments only if REISER4_LARGE_KEY is on.
+ */
+#define ON_LARGE_KEY(...) __VA_ARGS__
+#else
+#define ON_LARGE_KEY(...)
+#endif
+
+/* __FS_REISER4_DEBUG_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/dformat.h linux-2.6.20/fs/reiser4/dformat.h
--- linux-2.6.20.orig/fs/reiser4/dformat.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/dformat.h   2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,70 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Formats of on-disk data and conversion functions. */
+
+/* put all item formats in the files describing the particular items,
+   our model is, everything you need to do to add an item to reiser4,
+   (excepting the changes to the plugin that uses the item which go
+   into the file defining that plugin), you put into one file. */
+/* Data on disk are stored in little-endian format.
+   To declare fields of on-disk structures, use d8, d16, d32 and d64.
+   d??tocpu() and cputod??() to convert. */
+
+#if !defined( __FS_REISER4_DFORMAT_H__ )
+#define __FS_REISER4_DFORMAT_H__
+
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+#include <linux/types.h>
+
+typedef __u8 d8;
+typedef __le16 d16;
+typedef __le32 d32;
+typedef __le64 d64;
+
+#define PACKED __attribute__((packed))
+
+/* data-type for block number */
+typedef __u64 reiser4_block_nr;
+
+/* data-type for block number on disk, disk format */
+typedef __le64 reiser4_dblock_nr;
+
+/**
+ * disk_addr_eq - compare disk addresses
+ * @b1: pointer to block number ot compare
+ * @b2: pointer to block number ot compare
+ *
+ * Returns true if if disk addresses are the same
+ */
+static inline int disk_addr_eq(const reiser4_block_nr *b1,
+                              const reiser4_block_nr * b2)
+{
+       assert("nikita-1033", b1 != NULL);
+       assert("nikita-1266", b2 != NULL);
+
+       return !memcmp(b1, b2, sizeof *b1);
+}
+
+/* structure of master reiser4 super block */
+typedef struct reiser4_master_sb {
+       char magic[16];         /* "ReIsEr4" */
+       __le16 disk_plugin_id;  /* id of disk layout plugin */
+       __le16 blocksize;
+       char uuid[16];          /* unique id */
+       char label[16];         /* filesystem label */
+       __le64 diskmap;         /* location of the diskmap. 0 if not present */
+} reiser4_master_sb;
+
+/* __FS_REISER4_DFORMAT_H__ */
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/dscale.c linux-2.6.20/fs/reiser4/dscale.c
--- linux-2.6.20.orig/fs/reiser4/dscale.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/dscale.c    2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,174 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Scalable on-disk integers */
+
+/*
+ * Various on-disk structures contain integer-like structures. Stat-data
+ * contain [yes, "data" is plural, check the dictionary] file size, link
+ * count; extent unit contains extent width etc. To accommodate for general
+ * case enough space is reserved to keep largest possible value. 64 bits in
+ * all cases above. But in overwhelming majority of cases numbers actually
+ * stored in these fields will be comparatively small and reserving 8 bytes is
+ * a waste of precious disk bandwidth.
+ *
+ * Scalable integers are one way to solve this problem. dscale_write()
+ * function stores __u64 value in the given area consuming from 1 to 9 bytes,
+ * depending on the magnitude of the value supplied. dscale_read() reads value
+ * previously stored by dscale_write().
+ *
+ * dscale_write() produces format not completely unlike of UTF: two highest
+ * bits of the first byte are used to store "tag". One of 4 possible tag
+ * values is chosen depending on the number being encoded:
+ *
+ *           0 ... 0x3f               => 0           [table 1]
+ *        0x40 ... 0x3fff             => 1
+ *      0x4000 ... 0x3fffffff         => 2
+ *  0x40000000 ... 0xffffffffffffffff => 3
+ *
+ * (see dscale_range() function)
+ *
+ * Values in the range 0x40000000 ... 0xffffffffffffffff require 8 full bytes
+ * to be stored, so in this case there is no place in the first byte to store
+ * tag. For such values tag is stored in an extra 9th byte.
+ *
+ * As _highest_ bits are used for the test (which is natural) scaled integers
+ * are stored in BIG-ENDIAN format in contrast with the rest of reiser4 which
+ * uses LITTLE-ENDIAN.
+ *
+ */
+
+#include "debug.h"
+#include "dscale.h"
+
+/* return tag of scaled integer stored at @address */
+static int gettag(const unsigned char *address)
+{
+       /* tag is stored in two highest bits */
+       return (*address) >> 6;
+}
+
+/* clear tag from value. Clear tag embedded into @value. */
+static void cleartag(__u64 * value, int tag)
+{
+       /*
+        * W-w-what ?!
+        *
+        * Actually, this is rather simple: @value passed here was read by
+        * dscale_read(), converted from BIG-ENDIAN, and padded to __u64 by
+        * zeroes. Tag is still stored in the highest (arithmetically)
+        * non-zero bits of @value, but relative position of tag within __u64
+        * depends on @tag.
+        *
+        * For example if @tag is 0, it's stored 2 highest bits of lowest
+        * byte, and its offset (counting from lowest bit) is 8 - 2 == 6 bits.
+        *
+        * If tag is 1, it's stored in two highest bits of 2nd lowest byte,
+        * and it's offset if (2 * 8) - 2 == 14 bits.
+        *
+        * See table 1 above for details.
+        *
+        * All these cases are captured by the formula:
+        */
+       *value &= ~(3 << (((1 << tag) << 3) - 2));
+       /*
+        * That is, clear two (3 == 0t11) bits at the offset
+        *
+        *                  8 * (2 ^ tag) - 2,
+        *
+        * that is, two highest bits of (2 ^ tag)-th byte of @value.
+        */
+}
+
+/* return tag for @value. See table 1 above for details. */
+static int dscale_range(__u64 value)
+{
+       if (value > 0x3fffffff)
+               return 3;
+       if (value > 0x3fff)
+               return 2;
+       if (value > 0x3f)
+               return 1;
+       return 0;
+}
+
+/* restore value stored at @adderss by dscale_write() and return number of
+ * bytes consumed */
+int dscale_read(unsigned char *address, __u64 * value)
+{
+       int tag;
+
+       /* read tag */
+       tag = gettag(address);
+       switch (tag) {
+       case 3:
+               /* In this case tag is stored in an extra byte, skip this byte
+                * and decode value stored in the next 8 bytes.*/
+               *value = __be64_to_cpu(get_unaligned((__be64 *)(address + 1)));
+               /* worst case: 8 bytes for value itself plus one byte for
+                * tag. */
+               return 9;
+       case 0:
+               *value = get_unaligned(address);
+               break;
+       case 1:
+               *value = __be16_to_cpu(get_unaligned((__be16 *)address));
+               break;
+       case 2:
+               *value = __be32_to_cpu(get_unaligned((__be32 *)address));
+               break;
+       default:
+               return RETERR(-EIO);
+       }
+       /* clear tag embedded into @value */
+       cleartag(value, tag);
+       /* number of bytes consumed is (2 ^ tag)---see table 1. */
+       return 1 << tag;
+}
+
+/* store @value at @address and return number of bytes consumed */
+int dscale_write(unsigned char *address, __u64 value)
+{
+       int tag;
+       int shift;
+       __be64 v;
+       unsigned char *valarr;
+
+       tag = dscale_range(value);
+       v = __cpu_to_be64(value);
+       valarr = (unsigned char *)&v;
+       shift = (tag == 3) ? 1 : 0;
+       memcpy(address + shift, valarr + sizeof v - (1 << tag), 1 << tag);
+       *address |= (tag << 6);
+       return shift + (1 << tag);
+}
+
+/* number of bytes required to store @value */
+int dscale_bytes(__u64 value)
+{
+       int bytes;
+
+       bytes = 1 << dscale_range(value);
+       if (bytes == 8)
+               ++bytes;
+       return bytes;
+}
+
+/* returns true if @value and @other require the same number of bytes to be
+ * stored. Used by detect when data structure (like stat-data) has to be
+ * expanded or contracted. */
+int dscale_fit(__u64 value, __u64 other)
+{
+       return dscale_range(value) == dscale_range(other);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/dscale.h linux-2.6.20/fs/reiser4/dscale.h
--- linux-2.6.20.orig/fs/reiser4/dscale.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/dscale.h    2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,27 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Scalable on-disk integers. See dscale.h for details. */
+
+#if !defined( __FS_REISER4_DSCALE_H__ )
+#define __FS_REISER4_DSCALE_H__
+
+#include "dformat.h"
+
+extern int dscale_read(unsigned char *address, __u64 * value);
+extern int dscale_write(unsigned char *address, __u64 value);
+extern int dscale_bytes(__u64 value);
+extern int dscale_fit(__u64 value, __u64 other);
+
+/* __FS_REISER4_DSCALE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/entd.c linux-2.6.20/fs/reiser4/entd.c
--- linux-2.6.20.orig/fs/reiser4/entd.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/entd.c      2007-05-06 14:50:43.702976975 +0400
@@ -0,0 +1,335 @@
+/* Copyright 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Ent daemon. */
+
+#include "debug.h"
+#include "txnmgr.h"
+#include "tree.h"
+#include "entd.h"
+#include "super.h"
+#include "context.h"
+#include "reiser4.h"
+#include "vfs_ops.h"
+#include "page_cache.h"
+#include "inode.h"
+
+#include <linux/sched.h>       /* struct task_struct */
+#include <linux/suspend.h>
+#include <linux/kernel.h>
+#include <linux/writeback.h>
+#include <linux/time.h>                /* INITIAL_JIFFIES */
+#include <linux/backing-dev.h> /* bdi_write_congested */
+#include <linux/wait.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+#define DEF_PRIORITY 12
+#define MAX_ENTD_ITERS 10
+
+static void entd_flush(struct super_block *, struct wbq *);
+static int entd(void *arg);
+
+/*
+ * set ->comm field of end thread to make its state visible to the user level
+ */
+#define entd_set_comm(state)                                   \
+       snprintf(current->comm, sizeof(current->comm),  \
+                "ent:%s%s", super->s_id, (state))
+
+/**
+ * reiser4_init_entd - initialize entd context and start kernel daemon
+ * @super: super block to start ent thread for
+ *
+ * Creates entd contexts, starts kernel thread and waits until it
+ * initializes.
+ */
+int reiser4_init_entd(struct super_block *super)
+{
+       entd_context *ctx;
+
+       assert("nikita-3104", super != NULL);
+
+       ctx = get_entd_context(super);
+
+       memset(ctx, 0, sizeof *ctx);
+       spin_lock_init(&ctx->guard);
+       init_waitqueue_head(&ctx->wait);
+#if REISER4_DEBUG
+       INIT_LIST_HEAD(&ctx->flushers_list);
+#endif
+       /* lists of writepage requests */
+       INIT_LIST_HEAD(&ctx->todo_list);
+       INIT_LIST_HEAD(&ctx->done_list);
+       /* start entd */
+       ctx->tsk = kthread_run(entd, super, "ent:%s", super->s_id);
+       if (IS_ERR(ctx->tsk))
+               return PTR_ERR(ctx->tsk);
+       return 0;
+}
+
+static void put_wbq(struct wbq *rq)
+{
+       iput(rq->mapping->host);
+       complete(&rq->completion);
+}
+
+/* ent should be locked */
+static struct wbq *__get_wbq(entd_context * ent)
+{
+       struct wbq *wbq;
+
+       if (list_empty(&ent->todo_list))
+               return NULL;
+
+       ent->nr_todo_reqs --;
+       wbq = list_entry(ent->todo_list.next, struct wbq, link);
+       list_del_init(&wbq->link);
+       return wbq;
+}
+
+/* ent thread function */
+static int entd(void *arg)
+{
+       struct super_block *super;
+       entd_context *ent;
+       int done = 0;
+
+       super = arg;
+       /* do_fork() just copies task_struct into the new
+          thread. ->fs_context shouldn't be copied of course. This shouldn't
+          be a problem for the rest of the code though.
+        */
+       current->journal_info = NULL;
+
+       ent = get_entd_context(super);
+
+       while (!done) {
+               try_to_freeze();
+
+               spin_lock(&ent->guard);
+               while (ent->nr_todo_reqs != 0) {
+                       struct wbq *rq;
+
+                       assert("", list_empty(&ent->done_list));
+
+                       /* take request from the queue head */
+                       rq = __get_wbq(ent);
+                       assert("", rq != NULL);
+                       ent->cur_request = rq;
+                       spin_unlock(&ent->guard);
+
+                       entd_set_comm("!");
+                       entd_flush(super, rq);
+
+                       put_wbq(rq);
+
+                       /*
+                        * wakeup all requestors and iput their inodes
+                        */
+                       spin_lock(&ent->guard);
+                       while (!list_empty(&ent->done_list)) {
+                               rq = list_entry(ent->done_list.next, struct wbq, link);
+                               list_del_init(&rq->link);
+                               ent->nr_done_reqs --;
+                               spin_unlock(&ent->guard);
+                               assert("", rq->written == 1);
+                               put_wbq(rq);
+                               spin_lock(&ent->guard);
+                       }
+               }
+               spin_unlock(&ent->guard);
+
+               entd_set_comm(".");
+
+               {
+                       DEFINE_WAIT(__wait);
+
+                       do {
+                               prepare_to_wait(&ent->wait, &__wait, TASK_INTERRUPTIBLE);
+                               if (kthread_should_stop()) {
+                                       done = 1;
+                                       break;
+                               }
+                               if (ent->nr_todo_reqs != 0)
+                                       break;
+                               schedule();
+                       } while (0);
+                       finish_wait(&ent->wait, &__wait);
+               }
+       }
+       BUG_ON(ent->nr_todo_reqs != 0);
+       return 0;
+}
+
+/**
+ * reiser4_done_entd - stop entd kernel thread
+ * @super: super block to stop ent thread for
+ *
+ * It is called on umount. Sends stop signal to entd and wait until it handles
+ * it.
+ */
+void reiser4_done_entd(struct super_block *super)
+{
+       entd_context *ent;
+
+       assert("nikita-3103", super != NULL);
+
+       ent = get_entd_context(super);
+       assert("zam-1055", ent->tsk != NULL);
+       kthread_stop(ent->tsk);
+}
+
+/* called at the beginning of jnode_flush to register flusher thread with ent
+ * daemon */
+void reiser4_enter_flush(struct super_block *super)
+{
+       entd_context *ent;
+
+       assert("zam-1029", super != NULL);
+       ent = get_entd_context(super);
+
+       assert("zam-1030", ent != NULL);
+
+       spin_lock(&ent->guard);
+       ent->flushers++;
+#if REISER4_DEBUG
+       list_add(&get_current_context()->flushers_link, &ent->flushers_list);
+#endif
+       spin_unlock(&ent->guard);
+}
+
+/* called at the end of jnode_flush */
+void reiser4_leave_flush(struct super_block *super)
+{
+       entd_context *ent;
+       int wake_up_ent;
+
+       assert("zam-1027", super != NULL);
+       ent = get_entd_context(super);
+
+       assert("zam-1028", ent != NULL);
+
+       spin_lock(&ent->guard);
+       ent->flushers--;
+       wake_up_ent = (ent->flushers == 0 && ent->nr_todo_reqs != 0);
+#if REISER4_DEBUG
+       list_del_init(&get_current_context()->flushers_link);
+#endif
+       spin_unlock(&ent->guard);
+       if (wake_up_ent)
+               wake_up(&ent->wait);
+}
+
+#define ENTD_CAPTURE_APAGE_BURST SWAP_CLUSTER_MAX
+
+static void entd_flush(struct super_block *super, struct wbq *rq)
+{
+       reiser4_context ctx;
+       int tmp;
+
+       init_stack_context(&ctx, super);
+       ctx.entd = 1;
+       ctx.gfp_mask = GFP_NOFS;
+
+       rq->wbc->range_start = page_offset(rq->page);
+       rq->wbc->range_end = rq->wbc->range_start +
+               (ENTD_CAPTURE_APAGE_BURST << PAGE_CACHE_SHIFT);
+       tmp = rq->wbc->nr_to_write;
+       rq->mapping->a_ops->writepages(rq->mapping, rq->wbc);
+
+       if (rq->wbc->nr_to_write > 0) {
+               rq->wbc->range_start = 0;
+               rq->wbc->range_end = LLONG_MAX;
+               generic_sync_sb_inodes(super, rq->wbc);
+       }
+       rq->wbc->nr_to_write = ENTD_CAPTURE_APAGE_BURST;
+       reiser4_writeout(super, rq->wbc);
+
+       context_set_commit_async(&ctx);
+       reiser4_exit_context(&ctx);
+}
+
+/**
+ * write_page_by_ent - ask entd thread to flush this page as part of slum
+ * @page: page to be written
+ * @wbc: writeback control passed to reiser4_writepage
+ *
+ * Creates a request, puts it on entd list of requests, wakeups entd if
+ * necessary, waits until entd completes with the request.
+ */
+int write_page_by_ent(struct page *page, struct writeback_control *wbc)
+{
+       struct super_block *sb;
+       struct inode *inode;
+       entd_context *ent;
+       struct wbq rq;
+
+       assert("", PageLocked(page));
+       assert("", page->mapping != NULL);
+
+       sb = page->mapping->host->i_sb;
+       ent = get_entd_context(sb);
+       assert("", ent && ent->done == 0);
+
+       /*
+        * we are going to unlock page and ask ent thread to write the
+        * page. Re-dirty page before unlocking so that if ent thread fails to
+        * write it - it will remain dirty
+        */
+       reiser4_set_page_dirty_internal(page);
+
+       /*
+        * pin inode in memory, unlock page, entd_flush will iput. We can not
+        * iput here becasue we can not allow delete_inode to be called here
+        */
+       inode = igrab(page->mapping->host);
+       unlock_page(page);
+       if (inode == NULL)
+               /* inode is getting freed */
+               return 0;
+
+       /* init wbq */
+       INIT_LIST_HEAD(&rq.link);
+       rq.magic = WBQ_MAGIC;
+       rq.wbc = wbc;
+       rq.page = page;
+       rq.mapping = inode->i_mapping;
+       rq.node = NULL;
+       rq.written = 0;
+       init_completion(&rq.completion);
+
+       /* add request to entd's list of writepage requests */
+       spin_lock(&ent->guard);
+       ent->nr_todo_reqs++;
+       list_add_tail(&rq.link, &ent->todo_list);
+       if (ent->nr_todo_reqs == 1)
+               wake_up(&ent->wait);
+
+       spin_unlock(&ent->guard);
+
+       /* wait until entd finishes */
+       wait_for_completion(&rq.completion);
+
+       if (rq.written)
+               /* Eventually ENTD has written the page to disk. */
+               return 0;
+       return 0;
+}
+
+int wbq_available(void)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+       entd_context *ent = get_entd_context(sb);
+       return ent->nr_todo_reqs;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/entd.h linux-2.6.20/fs/reiser4/entd.h
--- linux-2.6.20.orig/fs/reiser4/entd.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/entd.h      2007-05-06 14:50:43.706978224 +0400
@@ -0,0 +1,90 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Ent daemon. */
+
+#ifndef __ENTD_H__
+#define __ENTD_H__
+
+#include "context.h"
+
+#include <linux/fs.h>
+#include <linux/completion.h>
+#include <linux/wait.h>
+#include <linux/spinlock.h>
+#include <linux/sched.h>       /* for struct task_struct */
+
+#define WBQ_MAGIC 0x7876dc76
+
+/* write-back request. */
+struct wbq {
+       int magic;
+       struct list_head link; /* list head of this list is in entd context */
+       struct writeback_control *wbc;
+       struct page *page;
+       struct address_space *mapping;
+       struct completion completion;
+       jnode *node; /* set if ent thread captured requested page */
+       int written; /* set if ent thread wrote requested page */
+};
+
+/* ent-thread context. This is used to synchronize starting/stopping ent
+ * threads. */
+typedef struct entd_context {
+        /* wait queue that ent thread waits on for more work. It's
+         * signaled by write_page_by_ent(). */
+       wait_queue_head_t wait;
+       /* spinlock protecting other fields */
+       spinlock_t guard;
+       /* ent thread */
+       struct task_struct *tsk;
+       /* set to indicate that ent thread should leave. */
+       int done;
+       /* counter of active flushers */
+       int flushers;
+       /*
+        * when reiser4_writepage asks entd to write a page - it adds struct
+        * wbq to this list
+        */
+       struct list_head todo_list;
+       /* number of elements on the above list */
+       int nr_todo_reqs;
+
+       struct wbq *cur_request;
+       /*
+        * when entd writes a page it moves write-back request from todo_list
+        * to done_list. This list is used at the end of entd iteration to
+        * wakeup requestors and iput inodes.
+        */
+       struct list_head done_list;
+       /* number of elements on the above list */
+       int nr_done_reqs;
+
+#if REISER4_DEBUG
+       /* list of all active flushers */
+       struct list_head flushers_list;
+#endif
+} entd_context;
+
+extern int  reiser4_init_entd(struct super_block *);
+extern void reiser4_done_entd(struct super_block *);
+
+extern void reiser4_enter_flush(struct super_block *);
+extern void reiser4_leave_flush(struct super_block *);
+
+extern int write_page_by_ent(struct page *, struct writeback_control *);
+extern int wbq_available(void);
+extern void ent_writes_page(struct super_block *, struct page *);
+
+extern jnode *get_jnode_by_wbq(struct super_block *, struct wbq *);
+/* __ENTD_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/eottl.c linux-2.6.20/fs/reiser4/eottl.c
--- linux-2.6.20.orig/fs/reiser4/eottl.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/eottl.c     2007-05-06 14:50:43.706978224 +0400
@@ -0,0 +1,509 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/node/node.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "tree_mod.h"
+#include "carry.h"
+#include "tree.h"
+#include "super.h"
+
+#include <linux/types.h>       /* for __u??  */
+
+/*
+ * Extents on the twig level (EOTTL) handling.
+ *
+ * EOTTL poses some problems to the tree traversal, that are better explained
+ * by example.
+ *
+ * Suppose we have block B1 on the twig level with the following items:
+ *
+ * 0. internal item I0 with key (0:0:0:0) (locality, key-type, object-id,
+ * offset)
+ * 1. extent item E1 with key (1:4:100:0), having 10 blocks of 4k each
+ * 2. internal item I2 with key (10:0:0:0)
+ *
+ * We are trying to insert item with key (5:0:0:0). Lookup finds node B1, and
+ * then intra-node lookup is done. This lookup finished on the E1, because the
+ * key we are looking for is larger than the key of E1 and is smaller than key
+ * the of I2.
+ *
+ * Here search is stuck.
+ *
+ * After some thought it is clear what is wrong here: extents on the twig level
+ * break some basic property of the *search* tree (on the pretext, that they
+ * restore property of balanced tree).
+ *
+ * Said property is the following: if in the internal node of the search tree
+ * we have [ ... Key1 Pointer Key2 ... ] then, all data that are or will be
+ * keyed in the tree with the Key such that Key1 <= Key < Key2 are accessible
+ * through the Pointer.
+ *
+ * This is not true, when Pointer is Extent-Pointer, simply because extent
+ * cannot expand indefinitely to the right to include any item with
+ *
+ *   Key1 <= Key <= Key2.
+ *
+ * For example, our E1 extent is only responsible for the data with keys
+ *
+ *   (1:4:100:0) <= key <= (1:4:100:0xffffffffffffffff), and
+ *
+ * so, key range
+ *
+ *   ( (1:4:100:0xffffffffffffffff), (10:0:0:0) )
+ *
+ * is orphaned: there is no way to get there from the tree root.
+ *
+ * In other words, extent pointers are different than normal child pointers as
+ * far as search tree is concerned, and this creates such problems.
+ *
+ * Possible solution for this problem is to insert our item into node pointed
+ * to by I2. There are some problems through:
+ *
+ * (1) I2 can be in a different node.
+ * (2) E1 can be immediately followed by another extent E2.
+ *
+ * (1) is solved by calling reiser4_get_right_neighbor() and accounting
+ * for locks/coords as necessary.
+ *
+ * (2) is more complex. Solution here is to insert new empty leaf node and
+ * insert internal item between E1 and E2 pointing to said leaf node. This is
+ * further complicated by possibility that E2 is in a different node, etc.
+ *
+ * Problems:
+ *
+ * (1) if there was internal item I2 immediately on the right of an extent E1
+ * we and we decided to insert new item S1 into node N2 pointed to by I2, then
+ * key of S1 will be less than smallest key in the N2. Normally, search key
+ * checks that key we are looking for is in the range of keys covered by the
+ * node key is being looked in. To work around of this situation, while
+ * preserving useful consistency check new flag CBK_TRUST_DK was added to the
+ * cbk falgs bitmask. This flag is automatically set on entrance to the
+ * coord_by_key() and is only cleared when we are about to enter situation
+ * described above.
+ *
+ * (2) If extent E1 is immediately followed by another extent E2 and we are
+ * searching for the key that is between E1 and E2 we only have to insert new
+ * empty leaf node when coord_by_key was called for insertion, rather than just
+ * for lookup. To distinguish these cases, new flag CBK_FOR_INSERT was added to
+ * the cbk falgs bitmask. This flag is automatically set by coord_by_key calls
+ * performed by insert_by_key() and friends.
+ *
+ * (3) Insertion of new empty leaf node (possibly) requires balancing. In any
+ * case it requires modification of node content which is only possible under
+ * write lock. It may well happen that we only have read lock on the node where
+ * new internal pointer is to be inserted (common case: lookup of non-existent
+ * stat-data that fells between two extents). If only read lock is held, tree
+ * traversal is restarted with lock_level modified so that next time we hit
+ * this problem, write lock will be held. Once we have write lock, balancing
+ * will be performed.
+ */
+
+/**
+ * is_next_item_internal - check whether next item is internal
+ * @coord: coordinate of extent item in twig node
+ * @key: search key
+ * @lh: twig node lock handle
+ *
+ * Looks at the unit next to @coord. If it is an internal one - 1 is returned,
+ * @coord is set to that unit. If that unit is in right neighbor, @lh is moved
+ * to that node, @coord is set to its first unit. If next item is not internal
+ * or does not exist then 0 is returned, @coord and @lh are left unchanged. 2
+ * is returned if search restart has to be done.
+ */
+static int
+is_next_item_internal(coord_t *coord, const reiser4_key *key,
+                     lock_handle *lh)
+{
+       coord_t next;
+       lock_handle rn;
+       int result;
+
+       coord_dup(&next, coord);
+       if (coord_next_unit(&next) == 0) {
+               /* next unit is in this node */
+               if (item_is_internal(&next)) {
+                       coord_dup(coord, &next);
+                       return 1;
+               }
+               assert("vs-3", item_is_extent(&next));
+               return 0;
+       }
+
+       /*
+        * next unit either does not exist or is in right neighbor. If it is in
+        * right neighbor we have to check right delimiting key because
+        * concurrent thread could get their first and insert item with a key
+        * smaller than @key
+        */
+       read_lock_dk(current_tree);
+       result = keycmp(key, znode_get_rd_key(coord->node));
+       read_unlock_dk(current_tree);
+       assert("vs-6", result != EQUAL_TO);
+       if (result == GREATER_THAN)
+               return 2;
+
+       /* lock right neighbor */
+       init_lh(&rn);
+       result = reiser4_get_right_neighbor(&rn, coord->node,
+                                           znode_is_wlocked(coord->node) ?
+                                           ZNODE_WRITE_LOCK : ZNODE_READ_LOCK,
+                                           GN_CAN_USE_UPPER_LEVELS);
+       if (result == -E_NO_NEIGHBOR) {
+               /* we are on the rightmost edge of the tree */
+               done_lh(&rn);
+               return 0;
+       }
+
+       if (result) {
+               assert("vs-4", result < 0);
+               done_lh(&rn);
+               return result;
+       }
+
+       /*
+        * check whether concurrent thread managed to insert item with a key
+        * smaller than @key
+        */
+       read_lock_dk(current_tree);
+       result = keycmp(key, znode_get_ld_key(rn.node));
+       read_unlock_dk(current_tree);
+       assert("vs-6", result != EQUAL_TO);
+       if (result == GREATER_THAN) {
+               done_lh(&rn);
+               return 2;
+       }
+
+       result = zload(rn.node);
+       if (result) {
+               assert("vs-5", result < 0);
+               done_lh(&rn);
+               return result;
+       }
+
+       coord_init_first_unit(&next, rn.node);
+       if (item_is_internal(&next)) {
+               /*
+                * next unit is in right neighbor and it is an unit of internal
+                * item. Unlock coord->node. Move @lh to right neighbor. @coord
+                * is set to the first unit of right neighbor.
+                */
+               coord_dup(coord, &next);
+               zrelse(rn.node);
+               done_lh(lh);
+               move_lh(lh, &rn);
+               return 1;
+       }
+
+       /*
+        * next unit is unit of extent item. Return without chaning @lh and
+        * @coord.
+        */
+       assert("vs-6", item_is_extent(&next));
+       zrelse(rn.node);
+       done_lh(&rn);
+       return 0;
+}
+
+/**
+ * rd_key - calculate key of an item next to the given one
+ * @coord: position in a node
+ * @key: storage for result key
+ *
+ * @coord is set between items or after the last item in a node. Calculate key
+ * of item to the right of @coord.
+ */
+static reiser4_key *rd_key(const coord_t *coord, reiser4_key *key)
+{
+       coord_t dup;
+
+       assert("nikita-2281", coord_is_between_items(coord));
+       coord_dup(&dup, coord);
+
+       if (coord_set_to_right(&dup) == 0)
+               /* next item is in this node. Return its key. */
+               unit_key_by_coord(&dup, key);
+       else {
+               /*
+                * next item either does not exist or is in right
+                * neighbor. Return znode's right delimiting key.
+                */
+               read_lock_dk(current_tree);
+               *key = *znode_get_rd_key(coord->node);
+               read_unlock_dk(current_tree);
+       }
+       return key;
+}
+
+/**
+ * add_empty_leaf - insert empty leaf between two extents
+ * @insert_coord: position in twig node between two extents
+ * @lh: twig node lock handle
+ * @key: left delimiting key of new node
+ * @rdkey: right delimiting key of new node
+ *
+ * Inserts empty leaf node between two extent items. It is necessary when we
+ * have to insert an item on leaf level between two extents (items on the twig
+ * level).
+ */
+static int
+add_empty_leaf(coord_t *insert_coord, lock_handle *lh,
+              const reiser4_key *key, const reiser4_key *rdkey)
+{
+       int result;
+       carry_pool *pool;
+       carry_level *todo;
+       reiser4_item_data *item;
+       carry_insert_data *cdata;
+       carry_op *op;
+       znode *node;
+       reiser4_tree *tree;
+
+       assert("vs-49827", znode_contains_key_lock(insert_coord->node, key));
+       tree = znode_get_tree(insert_coord->node);
+       node = reiser4_new_node(insert_coord->node, LEAF_LEVEL);
+       if (IS_ERR(node))
+               return PTR_ERR(node);
+
+       /* setup delimiting keys for node being inserted */
+       write_lock_dk(tree);
+       znode_set_ld_key(node, key);
+       znode_set_rd_key(node, rdkey);
+       ON_DEBUG(node->creator = current);
+       ON_DEBUG(node->first_key = *key);
+       write_unlock_dk(tree);
+
+       ZF_SET(node, JNODE_ORPHAN);
+
+       /*
+        * allocate carry_pool, 3 carry_level-s, reiser4_item_data and
+        * carry_insert_data
+        */
+       pool = init_carry_pool(sizeof(*pool) + 3 * sizeof(*todo) +
+                              sizeof(*item) + sizeof(*cdata));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       todo = (carry_level *) (pool + 1);
+       init_carry_level(todo, pool);
+
+       item = (reiser4_item_data *) (todo + 3);
+       cdata = (carry_insert_data *) (item + 1);
+
+       op = reiser4_post_carry(todo, COP_INSERT, insert_coord->node, 0);
+       if (!IS_ERR(op)) {
+               cdata->coord = insert_coord;
+               cdata->key = key;
+               cdata->data = item;
+               op->u.insert.d = cdata;
+               op->u.insert.type = COPT_ITEM_DATA;
+               build_child_ptr_data(node, item);
+               item->arg = NULL;
+               /* have @insert_coord to be set at inserted item after
+                  insertion is done */
+               todo->track_type = CARRY_TRACK_CHANGE;
+               todo->tracked = lh;
+
+               result = reiser4_carry(todo, NULL);
+               if (result == 0) {
+                       /*
+                        * pin node in memory. This is necessary for
+                        * znode_make_dirty() below.
+                        */
+                       result = zload(node);
+                       if (result == 0) {
+                               lock_handle local_lh;
+
+                               /*
+                                * if we inserted new child into tree we have
+                                * to mark it dirty so that flush will be able
+                                * to process it.
+                                */
+                               init_lh(&local_lh);
+                               result = longterm_lock_znode(&local_lh, node,
+                                                            ZNODE_WRITE_LOCK,
+                                                            ZNODE_LOCK_LOPRI);
+                               if (result == 0) {
+                                       znode_make_dirty(node);
+
+                                       /*
+                                        * when internal item pointing to @node
+                                        * was inserted into twig node
+                                        * create_hook_internal did not connect
+                                        * it properly because its right
+                                        * neighbor was not known. Do it
+                                        * here
+                                        */
+                                       write_lock_tree(tree);
+                                       assert("nikita-3312",
+                                              znode_is_right_connected(node));
+                                       assert("nikita-2984",
+                                              node->right == NULL);
+                                       ZF_CLR(node, JNODE_RIGHT_CONNECTED);
+                                       write_unlock_tree(tree);
+                                       result =
+                                           connect_znode(insert_coord, node);
+                                       ON_DEBUG(if (result == 0) check_dkeys(node););
+
+                                       done_lh(lh);
+                                       move_lh(lh, &local_lh);
+                                       assert("vs-1676", node_is_empty(node));
+                                       coord_init_first_unit(insert_coord,
+                                                             node);
+                               } else {
+                                       warning("nikita-3136",
+                                               "Cannot lock child");
+                               }
+                               done_lh(&local_lh);
+                               zrelse(node);
+                       }
+               }
+       } else
+               result = PTR_ERR(op);
+       zput(node);
+       done_carry_pool(pool);
+       return result;
+}
+
+/**
+ * handle_eottl - handle extent-on-the-twig-level cases in tree traversal
+ * @h: search handle
+ * @outcome: flag saying whether search has to restart or is done
+ *
+ * Handles search on twig level. If this function completes search itself then
+ * it returns 1. If search has to go one level down then 0 is returned. If
+ * error happens then LOOKUP_DONE is returned via @outcome and error code is saved
+ * in @h->result.
+ */
+int handle_eottl(cbk_handle *h, int *outcome)
+{
+       int result;
+       reiser4_key key;
+       coord_t *coord;
+
+       coord = h->coord;
+
+       if (h->level != TWIG_LEVEL ||
+           (coord_is_existing_item(coord) && item_is_internal(coord))) {
+               /* Continue to traverse tree downward. */
+               return 0;
+       }
+
+       /*
+        * make sure that @h->coord is set to twig node and that it is either
+        * set to extent item or after extent item
+        */
+       assert("vs-356", h->level == TWIG_LEVEL);
+       assert("vs-357", ( {
+                         coord_t lcoord;
+                         coord_dup(&lcoord, coord);
+                         check_me("vs-733", coord_set_to_left(&lcoord) == 0);
+                         item_is_extent(&lcoord);
+                         }
+              ));
+
+       if (*outcome == NS_FOUND) {
+               /* we have found desired key on twig level in extent item */
+               h->result = CBK_COORD_FOUND;
+               *outcome = LOOKUP_DONE;
+               return 1;
+       }
+
+       if (!(h->flags & CBK_FOR_INSERT)) {
+               /* tree traversal is not for insertion. Just return
+                  CBK_COORD_NOTFOUND. */
+               h->result = CBK_COORD_NOTFOUND;
+               *outcome = LOOKUP_DONE;
+               return 1;
+       }
+
+       /* take a look at the item to the right of h -> coord */
+       result = is_next_item_internal(coord, h->key, h->active_lh);
+       if (unlikely(result < 0)) {
+               h->error = "get_right_neighbor failed";
+               h->result = result;
+               *outcome = LOOKUP_DONE;
+               return 1;
+       }
+       if (result == 0) {
+               /*
+                * item to the right is also an extent one. Allocate a new node
+                * and insert pointer to it after item h -> coord.
+                *
+                * This is a result of extents being located at the twig
+                * level. For explanation, see comment just above
+                * is_next_item_internal().
+                */
+               znode *loaded;
+
+               if (cbk_lock_mode(h->level, h) != ZNODE_WRITE_LOCK) {
+                       /*
+                        * we got node read locked, restart coord_by_key to
+                        * have write lock on twig level
+                        */
+                       h->lock_level = TWIG_LEVEL;
+                       h->lock_mode = ZNODE_WRITE_LOCK;
+                       *outcome = LOOKUP_REST;
+                       return 1;
+               }
+
+               loaded = coord->node;
+               result =
+                   add_empty_leaf(coord, h->active_lh, h->key,
+                                  rd_key(coord, &key));
+               if (result) {
+                       h->error = "could not add empty leaf";
+                       h->result = result;
+                       *outcome = LOOKUP_DONE;
+                       return 1;
+               }
+               /* added empty leaf is locked (h->active_lh), its parent node
+                  is unlocked, h->coord is set as EMPTY */
+               assert("vs-13", coord->between == EMPTY_NODE);
+               assert("vs-14", znode_is_write_locked(coord->node));
+               assert("vs-15",
+                      WITH_DATA(coord->node, node_is_empty(coord->node)));
+               assert("vs-16", jnode_is_leaf(ZJNODE(coord->node)));
+               assert("vs-17", coord->node == h->active_lh->node);
+               *outcome = LOOKUP_DONE;
+               h->result = CBK_COORD_NOTFOUND;
+               return 1;
+       } else if (result == 1) {
+               /*
+                * this is special case mentioned in the comment on
+                * tree.h:cbk_flags. We have found internal item immediately on
+                * the right of extent, and we are going to insert new item
+                * there. Key of item we are going to insert is smaller than
+                * leftmost key in the node pointed to by said internal item
+                * (otherwise search wouldn't come to the extent in the first
+                * place).
+                *
+                * This is a result of extents being located at the twig
+                * level. For explanation, see comment just above
+                * is_next_item_internal().
+                */
+               h->flags &= ~CBK_TRUST_DK;
+       } else {
+               assert("vs-8", result == 2);
+               *outcome = LOOKUP_REST;
+               return 1;
+       }
+       assert("vs-362", WITH_DATA(coord->node, item_is_internal(coord)));
+       return 0;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/estimate.c linux-2.6.20/fs/reiser4/estimate.c
--- linux-2.6.20.orig/fs/reiser4/estimate.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/estimate.c  2007-05-06 14:50:43.706978224 +0400
@@ -0,0 +1,111 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "debug.h"
+#include "dformat.h"
+#include "tree.h"
+#include "carry.h"
+#include "inode.h"
+#include "plugin/cluster.h"
+#include "plugin/item/ctail.h"
+
+/* this returns how many nodes might get dirty and added nodes if @children nodes are dirtied
+
+   Amount of internals which will get dirty or get allocated we estimate as 5% of the childs + 1 balancing. 1 balancing
+   is 2 neighbours, 2 new blocks and the current block on the leaf level, 2 neighbour nodes + the current (or 1
+   neighbour and 1 new and the current) on twig level, 2 neighbour nodes on upper levels and 1 for a new root. So 5 for
+   leaf level, 3 for twig level, 2 on upper + 1 for root.
+
+   Do not calculate the current node of the lowest level here - this is overhead only.
+
+   children is almost always 1 here. Exception is flow insertion
+*/
+static reiser4_block_nr
+max_balance_overhead(reiser4_block_nr childen, tree_level tree_height)
+{
+       reiser4_block_nr ten_percent;
+
+       ten_percent = ((103 * childen) >> 10);
+
+       /* If we have too many balancings at the time, tree height can raise on more
+          then 1. Assume that if tree_height is 5, it can raise on 1 only. */
+       return ((tree_height < 5 ? 5 : tree_height) * 2 + (4 + ten_percent));
+}
+
+/* this returns maximal possible number of nodes which can be modified plus number of new nodes which can be required to
+   perform insertion of one item into the tree */
+/* it is only called when tree height changes, or gets initialized */
+reiser4_block_nr calc_estimate_one_insert(tree_level height)
+{
+       return 1 + max_balance_overhead(1, height);
+}
+
+reiser4_block_nr estimate_one_insert_item(reiser4_tree * tree)
+{
+       return tree->estimate_one_insert;
+}
+
+/* this returns maximal possible number of nodes which can be modified plus number of new nodes which can be required to
+   perform insertion of one unit into an item in the tree */
+reiser4_block_nr estimate_one_insert_into_item(reiser4_tree * tree)
+{
+       /* estimate insert into item just like item insertion */
+       return tree->estimate_one_insert;
+}
+
+reiser4_block_nr estimate_one_item_removal(reiser4_tree * tree)
+{
+       /* on item removal reiser4 does not try to pack nodes more complact, so, only one node may be dirtied on leaf
+          level */
+       return tree->estimate_one_insert;
+}
+
+/* on leaf level insert_flow may add CARRY_FLOW_NEW_NODES_LIMIT new nodes and dirty 3 existing nodes (insert point and
+   both its neighbors). Max_balance_overhead should estimate number of blocks which may change/get added on internal
+   levels */
+reiser4_block_nr estimate_insert_flow(tree_level height)
+{
+       return 3 + CARRY_FLOW_NEW_NODES_LIMIT + max_balance_overhead(3 +
+                                                                    CARRY_FLOW_NEW_NODES_LIMIT,
+                                                                    height);
+}
+
+/* returnes max number of nodes can be occupied by disk cluster */
+static reiser4_block_nr estimate_cluster(struct inode * inode, int unprepped)
+{
+       int per_cluster;
+       per_cluster = (unprepped ? 1 : cluster_nrpages(inode));
+       return 3 + per_cluster +
+               max_balance_overhead(3 + per_cluster,
+                                    REISER4_MAX_ZTREE_HEIGHT);
+}
+
+/* how many nodes might get dirty and added
+   during insertion of a disk cluster */
+reiser4_block_nr estimate_insert_cluster(struct inode * inode)
+{
+       return estimate_cluster(inode, 1); /* 24 */
+}
+
+/* how many nodes might get dirty and added
+   during update of a (prepped or unprepped) disk cluster */
+reiser4_block_nr estimate_update_cluster(struct inode * inode)
+{
+       return estimate_cluster(inode, 0); /* 44, for 64K-cluster */
+}
+
+/* how many nodes occupied by a disk cluster might get dirty */
+reiser4_block_nr estimate_dirty_cluster(struct inode * inode)
+{
+       return cluster_nrpages(inode) + 4;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/export_ops.c linux-2.6.20/fs/reiser4/export_ops.c
--- linux-2.6.20.orig/fs/reiser4/export_ops.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/export_ops.c        2007-05-06 14:50:43.706978224 +0400
@@ -0,0 +1,295 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "inode.h"
+#include "plugin/plugin.h"
+
+/*
+ * Supported file-handle types
+ */
+typedef enum {
+       FH_WITH_PARENT = 0x10,  /* file handle with parent */
+       FH_WITHOUT_PARENT = 0x11        /* file handle without parent */
+} reiser4_fhtype;
+
+#define NFSERROR (255)
+
+/* initialize place-holder for object */
+static void object_on_wire_init(reiser4_object_on_wire *o)
+{
+       o->plugin = NULL;
+}
+
+/* finish with @o */
+static void object_on_wire_done(reiser4_object_on_wire *o)
+{
+       if (o->plugin != NULL)
+               o->plugin->wire.done(o);
+}
+
+/*
+ * read serialized object identity from @addr and store information about
+ * object in @obj. This is dual to encode_inode().
+ */
+static char *decode_inode(struct super_block *s, char *addr,
+                         reiser4_object_on_wire * obj)
+{
+       file_plugin *fplug;
+
+       /* identifier of object plugin is stored in the first two bytes,
+        * followed by... */
+       fplug = file_plugin_by_disk_id(reiser4_get_tree(s), (d16 *) addr);
+       if (fplug != NULL) {
+               addr += sizeof(d16);
+               obj->plugin = fplug;
+               assert("nikita-3520", fplug->wire.read != NULL);
+               /* plugin specific encoding of object identity. */
+               addr = fplug->wire.read(addr, obj);
+       } else
+               addr = ERR_PTR(RETERR(-EINVAL));
+       return addr;
+}
+
+/**
+ * reiser4_decode_fh - decode_fh of export operations
+ * @super: super block
+ * @fh: nfsd file handle
+ * @len: length of file handle
+ * @fhtype: type of file handle
+ * @acceptable: acceptability testing function
+ * @context: argument for @acceptable
+ *
+ * Returns dentry referring to the same file as @fh.
+ */
+static struct dentry *reiser4_decode_fh(struct super_block *super, __u32 *fh,
+                                       int len, int fhtype,
+                                       int (*acceptable) (void *context,
+                                                          struct dentry *de),
+                                       void *context)
+{
+       reiser4_context *ctx;
+       reiser4_object_on_wire object;
+       reiser4_object_on_wire parent;
+       char *addr;
+       int with_parent;
+
+       ctx = reiser4_init_context(super);
+       if (IS_ERR(ctx))
+               return (struct dentry *)ctx;
+
+       assert("vs-1482",
+              fhtype == FH_WITH_PARENT || fhtype == FH_WITHOUT_PARENT);
+
+       with_parent = (fhtype == FH_WITH_PARENT);
+
+       addr = (char *)fh;
+
+       object_on_wire_init(&object);
+       object_on_wire_init(&parent);
+
+       addr = decode_inode(super, addr, &object);
+       if (!IS_ERR(addr)) {
+               if (with_parent)
+                       addr = decode_inode(super, addr, &parent);
+               if (!IS_ERR(addr)) {
+                       struct dentry *d;
+                       typeof(super->s_export_op->find_exported_dentry) fn;
+
+                       fn = super->s_export_op->find_exported_dentry;
+                       assert("nikita-3521", fn != NULL);
+                       d = fn(super, &object, with_parent ? &parent : NULL,
+                              acceptable, context);
+                       if (d != NULL && !IS_ERR(d))
+                               /* FIXME check for -ENOMEM */
+                               reiser4_get_dentry_fsdata(d)->stateless = 1;
+                       addr = (char *)d;
+               }
+       }
+
+       object_on_wire_done(&object);
+       object_on_wire_done(&parent);
+
+       reiser4_exit_context(ctx);
+       return (void *)addr;
+}
+
+/*
+ * Object serialization support.
+ *
+ * To support knfsd file system provides export_operations that are used to
+ * construct and interpret NFS file handles. As a generalization of this,
+ * reiser4 object plugins have serialization support: it provides methods to
+ * create on-wire representation of identity of reiser4 object, and
+ * re-create/locate object given its on-wire identity.
+ *
+ */
+
+/*
+ * return number of bytes that on-wire representation of @inode's identity
+ * consumes.
+ */
+static int encode_inode_size(struct inode *inode)
+{
+       assert("nikita-3514", inode != NULL);
+       assert("nikita-3515", inode_file_plugin(inode) != NULL);
+       assert("nikita-3516", inode_file_plugin(inode)->wire.size != NULL);
+
+       return inode_file_plugin(inode)->wire.size(inode) + sizeof(d16);
+}
+
+/*
+ * store on-wire representation of @inode's identity at the area beginning at
+ * @start.
+ */
+static char *encode_inode(struct inode *inode, char *start)
+{
+       assert("nikita-3517", inode != NULL);
+       assert("nikita-3518", inode_file_plugin(inode) != NULL);
+       assert("nikita-3519", inode_file_plugin(inode)->wire.write != NULL);
+
+       /*
+        * first, store two-byte identifier of object plugin, then
+        */
+       save_plugin_id(file_plugin_to_plugin(inode_file_plugin(inode)),
+                      (d16 *) start);
+       start += sizeof(d16);
+       /*
+        * call plugin to serialize object's identity
+        */
+       return inode_file_plugin(inode)->wire.write(inode, start);
+}
+
+/* this returns number of 32 bit long numbers encoded in @lenp. 255 is
+ * returned if file handle can not be stored */
+/**
+ * reiser4_encode_fh - encode_fh of export operations
+ * @dentry:
+ * @fh:
+ * @lenp:
+ * @need_parent:
+ *
+ */
+static int
+reiser4_encode_fh(struct dentry *dentry, __u32 *fh, int *lenp,
+                 int need_parent)
+{
+       struct inode *inode;
+       struct inode *parent;
+       char *addr;
+       int need;
+       int delta;
+       int result;
+       reiser4_context *ctx;
+
+       /*
+        * knfsd asks as to serialize object in @dentry, and, optionally its
+        * parent (if need_parent != 0).
+        *
+        * encode_inode() and encode_inode_size() is used to build
+        * representation of object and its parent. All hard work is done by
+        * object plugins.
+        */
+       inode = dentry->d_inode;
+       parent = dentry->d_parent->d_inode;
+
+       addr = (char *)fh;
+
+       need = encode_inode_size(inode);
+       if (need < 0)
+               return NFSERROR;
+       if (need_parent) {
+               delta = encode_inode_size(parent);
+               if (delta < 0)
+                       return NFSERROR;
+               need += delta;
+       }
+
+       ctx = reiser4_init_context(dentry->d_inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       if (need <= sizeof(__u32) * (*lenp)) {
+               addr = encode_inode(inode, addr);
+               if (need_parent)
+                       addr = encode_inode(parent, addr);
+
+               /* store in lenp number of 32bit words required for file
+                * handle. */
+               *lenp = (need + sizeof(__u32) - 1) >> 2;
+               result = need_parent ? FH_WITH_PARENT : FH_WITHOUT_PARENT;
+       } else
+               /* no enough space in file handle */
+               result = NFSERROR;
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/**
+ * reiser4_get_dentry_parent - get_parent of export operations
+ * @child:
+ *
+ */
+static struct dentry *reiser4_get_dentry_parent(struct dentry *child)
+{
+       struct inode *dir;
+       dir_plugin *dplug;
+
+       assert("nikita-3527", child != NULL);
+       /* see comment in reiser4_get_dentry() about following assertion */
+       assert("nikita-3528", is_in_reiser4_context());
+
+       dir = child->d_inode;
+       assert("nikita-3529", dir != NULL);
+       dplug = inode_dir_plugin(dir);
+       assert("nikita-3531", ergo(dplug != NULL, dplug->get_parent != NULL));
+       if (dplug != NULL)
+               return dplug->get_parent(dir);
+       else
+               return ERR_PTR(RETERR(-ENOTDIR));
+}
+
+/**
+ * reiser4_get_dentry - get_dentry of export operations
+ * @super:
+ * @data:
+ *
+ *
+ */
+static struct dentry *reiser4_get_dentry(struct super_block *super, void *data)
+{
+       reiser4_object_on_wire *o;
+
+       assert("nikita-3522", super != NULL);
+       assert("nikita-3523", data != NULL);
+       /*
+        * this is only supposed to be called by
+        *
+        *     reiser4_decode_fh->find_exported_dentry
+        *
+        * so, reiser4_context should be here already.
+        */
+       assert("nikita-3526", is_in_reiser4_context());
+
+       o = (reiser4_object_on_wire *)data;
+       assert("nikita-3524", o->plugin != NULL);
+       assert("nikita-3525", o->plugin->wire.get != NULL);
+
+       return o->plugin->wire.get(super, o);
+}
+
+struct export_operations reiser4_export_operations = {
+       .encode_fh = reiser4_encode_fh,
+       .decode_fh = reiser4_decode_fh,
+       .get_parent = reiser4_get_dentry_parent,
+       .get_dentry = reiser4_get_dentry
+};
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/flush.c linux-2.6.20/fs/reiser4/flush.c
--- linux-2.6.20.orig/fs/reiser4/flush.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/flush.c     2007-05-06 14:50:43.000000000 +0400
@@ -0,0 +1,3622 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* The design document for this file is at http://www.namesys.com/v4/v4.html. */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/plugin.h"
+#include "plugin/object.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "carry.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "page_cache.h"
+#include "wander.h"
+#include "super.h"
+#include "entd.h"
+#include "reiser4.h"
+#include "flush.h"
+#include "writeout.h"
+
+#include <asm/atomic.h>
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/mm.h>          /* for struct page */
+#include <linux/bio.h>         /* for struct bio */
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+
+/* IMPLEMENTATION NOTES */
+
+/* PARENT-FIRST: Some terminology: A parent-first traversal is a way of assigning a total
+   order to the nodes of the tree in which the parent is placed before its children, which
+   are ordered (recursively) in left-to-right order.  When we speak of a "parent-first preceder", it
+   describes the node that "came before in forward parent-first order".  When we speak of a
+   "parent-first follower", it describes the node that "comes next in parent-first
+   order" (alternatively the node that "came before in reverse parent-first order").
+
+   The following pseudo-code prints the nodes of a tree in forward parent-first order:
+
+   void parent_first (node)
+   {
+     print_node (node);
+     if (node->level > leaf) {
+       for (i = 0; i < num_children; i += 1) {
+         parent_first (node->child[i]);
+       }
+     }
+   }
+*/
+
+/* JUST WHAT ARE WE TRYING TO OPTIMIZE, HERE?  The idea is to optimize block allocation so
+   that a left-to-right scan of the tree's data (i.e., the leaves in left-to-right order)
+   can be accomplished with sequential reads, which results in reading nodes in their
+   parent-first order.  This is a read-optimization aspect of the flush algorithm, and
+   there is also a write-optimization aspect, which is that we wish to make large
+   sequential writes to the disk by allocating or reallocating blocks so that they can be
+   written in sequence.  Sometimes the read-optimization and write-optimization goals
+   conflict with each other, as we discuss in more detail below.
+*/
+
+/* STATE BITS: The flush code revolves around the state of the jnodes it covers.  Here are
+   the relevant jnode->state bits and their relevence to flush:
+
+     JNODE_DIRTY: If a node is dirty, it must be flushed.  But in order to be written it
+     must be allocated first.  In order to be considered allocated, the jnode must have
+     exactly one of { JNODE_OVRWR, JNODE_RELOC } set.  These two bits are exclusive, and
+     all dirtied jnodes eventually have one of these bits set during each transaction.
+
+     JNODE_CREATED: The node was freshly created in its transaction and has no previous
+     block address, so it is unconditionally assigned to be relocated, although this is
+     mainly for code-convenience.  It is not being 'relocated' from anything, but in
+     almost every regard it is treated as part of the relocate set.  The JNODE_CREATED bit
+     remains set even after JNODE_RELOC is set, so the actual relocate can be
+     distinguished from the created-and-allocated set easily: relocate-set members
+     (belonging to the preserve-set) have (JNODE_RELOC) set and created-set members which
+     have no previous location to preserve have (JNODE_RELOC | JNODE_CREATED) set.
+
+     JNODE_OVRWR: The node belongs to atom's overwrite set. The flush algorithm made the
+     decision to maintain the pre-existing location for this node and it will be written
+     to the wandered-log.
+
+     JNODE_RELOC: The flush algorithm made the decision to relocate this block (if it was
+     not created, see note above).  A block with JNODE_RELOC set is eligible for
+     early-flushing and may be submitted during flush_empty_queues.  When the JNODE_RELOC
+     bit is set on a znode, the parent node's internal item is modified and the znode is
+     rehashed.
+
+     JNODE_SQUEEZABLE: Before shifting everything left, the flush algorithm scans the node
+     and calls plugin->f.squeeze() method for its items. By this technology we update disk
+     clusters of cryptcompress objects. Also if leftmost point that was found by flush scan
+     has this flag (races with write(), rare case) the flush algorythm makes the decision
+     to pass it to squalloc() in spite of its flushprepped status for squeezing, not for
+     repeated allocation.
+
+     JNODE_FLUSH_QUEUED: This bit is set when a call to flush enters the jnode into its
+     flush queue.  This means the jnode is not on any clean or dirty list, instead it is
+     moved to one of the flush queue (see flush_queue.h) object private list. This
+     prevents multiple concurrent flushes from attempting to start flushing from the
+     same node.
+
+     (DEAD STATE BIT) JNODE_FLUSH_BUSY: This bit was set during the bottom-up
+     squeeze-and-allocate on a node while its children are actively being squeezed and
+     allocated.  This flag was created to avoid submitting a write request for a node
+     while its children are still being allocated and squeezed. Then flush queue was
+     re-implemented to allow unlimited number of nodes be queued. This flag support was
+     commented out in source code because we decided that there was no reason to submit
+     queued nodes before jnode_flush() finishes.  However, current code calls fq_write()
+     during a slum traversal and may submit "busy nodes" to disk. Probably we can
+     re-enable the JNODE_FLUSH_BUSY bit support in future.
+
+   With these state bits, we describe a test used frequently in the code below,
+   jnode_is_flushprepped() (and the spin-lock-taking jnode_check_flushprepped()).  The
+   test for "flushprepped" returns true if any of the following are true:
+
+     - The node is not dirty
+     - The node has JNODE_RELOC set
+     - The node has JNODE_OVRWR set
+
+   If either the node is not dirty or it has already been processed by flush (and assigned
+   JNODE_OVRWR or JNODE_RELOC), then it is prepped.  If jnode_is_flushprepped() returns
+   true then flush has work to do on that node.
+*/
+
+/* FLUSH_PREP_ONCE_PER_TRANSACTION: Within a single transaction a node is never
+   flushprepped twice (unless an explicit call to flush_unprep is made as described in
+   detail below).  For example a node is dirtied, allocated, and then early-flushed to
+   disk and set clean.  Before the transaction commits, the page is dirtied again and, due
+   to memory pressure, the node is flushed again.  The flush algorithm will not relocate
+   the node to a new disk location, it will simply write it to the same, previously
+   relocated position again.
+*/
+
+/* THE BOTTOM-UP VS. TOP-DOWN ISSUE: This code implements a bottom-up algorithm where we
+   start at a leaf node and allocate in parent-first order by iterating to the right.  At
+   each step of the iteration, we check for the right neighbor.  Before advancing to the
+   right neighbor, we check if the current position and the right neighbor share the same
+   parent.  If they do not share the same parent, the parent is allocated before the right
+   neighbor.
+
+   This process goes recursively up the tree and squeeze nodes level by level as long as
+   the right neighbor and the current position have different parents, then it allocates
+   the right-neighbors-with-different-parents on the way back down.  This process is
+   described in more detail in flush_squalloc_changed_ancestor and the recursive function
+   squalloc_one_changed_ancestor.  But the purpose here is not to discuss the
+   specifics of the bottom-up approach as it is to contrast the bottom-up and top-down
+   approaches.
+
+   The top-down algorithm was implemented earlier (April-May 2002).  In the top-down
+   approach, we find a starting point by scanning left along each level past dirty nodes,
+   then going up and repeating the process until the left node and the parent node are
+   clean.  We then perform a parent-first traversal from the starting point, which makes
+   allocating in parent-first order trivial.  After one subtree has been allocated in this
+   manner, we move to the right, try moving upward, then repeat the parent-first
+   traversal.
+
+   Both approaches have problems that need to be addressed.  Both are approximately the
+   same amount of code, but the bottom-up approach has advantages in the order it acquires
+   locks which, at the very least, make it the better approach.  At first glance each one
+   makes the other one look simpler, so it is important to remember a few of the problems
+   with each one.
+
+   Main problem with the top-down approach: When you encounter a clean child during the
+   parent-first traversal, what do you do?  You would like to avoid searching through a
+   large tree of nodes just to find a few dirty leaves at the bottom, and there is not an
+   obvious solution.  One of the advantages of the top-down approach is that during the
+   parent-first traversal you check every child of a parent to see if it is dirty.  In
+   this way, the top-down approach easily handles the main problem of the bottom-up
+   approach: unallocated children.
+
+   The unallocated children problem is that before writing a node to disk we must make
+   sure that all of its children are allocated.  Otherwise, the writing the node means
+   extra I/O because the node will have to be written again when the child is finally
+   allocated.
+
+   WE HAVE NOT YET ELIMINATED THE UNALLOCATED CHILDREN PROBLEM.  Except for bugs, this
+   should not cause any file system corruption, it only degrades I/O performance because a
+   node may be written when it is sure to be written at least one more time in the same
+   transaction when the remaining children are allocated.  What follows is a description
+   of how we will solve the problem.
+*/
+
+/* HANDLING UNALLOCATED CHILDREN: During flush we may allocate a parent node then,
+   proceeding in parent first order, allocate some of its left-children, then encounter a
+   clean child in the middle of the parent.  We do not allocate the clean child, but there
+   may remain unallocated (dirty) children to the right of the clean child.  If we were to
+   stop flushing at this moment and write everything to disk, the parent might still
+   contain unallocated children.
+
+   We could try to allocate all the descendents of every node that we allocate, but this
+   is not necessary.  Doing so could result in allocating the entire tree: if the root
+   node is allocated then every unallocated node would have to be allocated before
+   flushing.  Actually, we do not have to write a node just because we allocate it.  It is
+   possible to allocate but not write a node during flush, when it still has unallocated
+   children.  However, this approach is probably not optimal for the following reason.
+
+   The flush algorithm is designed to allocate nodes in parent-first order in an attempt
+   to optimize reads that occur in the same order.  Thus we are read-optimizing for a
+   left-to-right scan through all the leaves in the system, and we are hoping to
+   write-optimize at the same time because those nodes will be written together in batch.
+   What happens, however, if we assign a block number to a node in its read-optimized
+   order but then avoid writing it because it has unallocated children?  In that
+   situation, we lose out on the write-optimization aspect because a node will have to be
+   written again to the its location on the device, later, which likely means seeking back
+   to that location.
+
+   So there are tradeoffs. We can choose either:
+
+   A. Allocate all unallocated children to preserve both write-optimization and
+   read-optimization, but this is not always desirable because it may mean having to
+   allocate and flush very many nodes at once.
+
+   B. Defer writing nodes with unallocated children, keep their read-optimized locations,
+   but sacrifice write-optimization because those nodes will be written again.
+
+   C. Defer writing nodes with unallocated children, but do not keep their read-optimized
+   locations.  Instead, choose to write-optimize them later, when they are written.  To
+   facilitate this, we "undo" the read-optimized allocation that was given to the node so
+   that later it can be write-optimized, thus "unpreparing" the flush decision.  This is a
+   case where we disturb the FLUSH_PREP_ONCE_PER_TRANSACTION rule described above.  By a
+   call to flush_unprep() we will: if the node was wandered, unset the JNODE_OVRWR bit;
+   if the node was relocated, unset the JNODE_RELOC bit, non-deferred-deallocate its block
+   location, and set the JNODE_CREATED bit, effectively setting the node back to an
+   unallocated state.
+
+   We will take the following approach in v4.0: for twig nodes we will always finish
+   allocating unallocated children (A).  For nodes with (level > TWIG) we will defer
+   writing and choose write-optimization (C).
+
+   To summarize, there are several parts to a solution that avoids the problem with
+   unallocated children:
+
+   FIXME-ZAM: Still no one approach is implemented to eliminate the "UNALLOCATED CHILDREN"
+   problem because there was an experiment which was done showed that we have 1-2 nodes
+   with unallocated children for thousands of written nodes.  The experiment was simple
+   like coping / deletion of linux kernel sources.  However the problem can arise in more
+   complex tests.  I think we have jnode_io_hook to insert a check for unallocated
+   children and see what kind of problem we have.
+
+   1. When flush reaches a stopping point (e.g., a clean node), it should continue calling
+   squeeze-and-allocate on any remaining unallocated children.  FIXME: Difficulty to
+   implement: should be simple -- amounts to adding a while loop to jnode_flush, see
+   comments in that function.
+
+   2. When flush reaches flush_empty_queue(), some of the (level > TWIG) nodes may still
+   have unallocated children.  If the twig level has unallocated children it is an
+   assertion failure.  If a higher-level node has unallocated children, then it should be
+   explicitly de-allocated by a call to flush_unprep().  FIXME: Difficulty to implement:
+   should be simple.
+
+   3. (CPU-Optimization) Checking whether a node has unallocated children may consume more
+   CPU cycles than we would like, and it is possible (but medium complexity) to optimize
+   this somewhat in the case where large sub-trees are flushed.  The following observation
+   helps: if both the left- and right-neighbor of a node are processed by the flush
+   algorithm then the node itself is guaranteed to have all of its children allocated.
+   However, the cost of this check may not be so expensive after all: it is not needed for
+   leaves and flush can guarantee this property for twigs.  That leaves only (level >
+   TWIG) nodes that have to be checked, so this optimization only helps if at least three
+   (level > TWIG) nodes are flushed in one pass, and the savings will be very small unless
+   there are many more (level > TWIG) nodes.  But if there are many (level > TWIG) nodes
+   then the number of blocks being written will be very large, so the savings may be
+   insignificant.  That said, the idea is to maintain both the left and right edges of
+   nodes that are processed in flush.  When flush_empty_queue() is called, a relatively
+   simple test will tell whether the (level > TWIG) node is on the edge.  If it is on the
+   edge, the slow check is necessary, but if it is in the interior then it can be assumed
+   to have all of its children allocated.  FIXME: medium complexity to implement, but
+   simple to verify given that we must have a slow check anyway.
+
+   4. (Optional) This part is optional, not for v4.0--flush should work independently of
+   whether this option is used or not.  Called RAPID_SCAN, the idea is to amend the
+   left-scan operation to take unallocated children into account.  Normally, the left-scan
+   operation goes left as long as adjacent nodes are dirty up until some large maximum
+   value (FLUSH_SCAN_MAXNODES) at which point it stops and begins flushing.  But scan-left
+   may stop at a position where there are unallocated children to the left with the same
+   parent.  When RAPID_SCAN is enabled, the ordinary scan-left operation stops after
+   FLUSH_RELOCATE_THRESHOLD, which is much smaller than FLUSH_SCAN_MAXNODES, then procedes
+   with a rapid scan.  The rapid scan skips all the interior children of a node--if the
+   leftmost child of a twig is dirty, check its left neighbor (the rightmost child of the
+   twig to the left).  If the left neighbor of the leftmost child is also dirty, then
+   continue the scan at the left twig and repeat.  This option will cause flush to
+   allocate more twigs in a single pass, but it also has the potential to write many more
+   nodes than would otherwise be written without the RAPID_SCAN option.  RAPID_SCAN
+   was partially implemented, code removed August 12, 2002 by JMACD.
+*/
+
+/* FLUSH CALLED ON NON-LEAF LEVEL.  Most of our design considerations assume that the
+   starting point for flush is a leaf node, but actually the flush code cares very little
+   about whether or not this is true.  It is possible that all the leaf nodes are flushed
+   and dirty parent nodes still remain, in which case jnode_flush() is called on a
+   non-leaf argument.  Flush doesn't care--it treats the argument node as if it were a
+   leaf, even when it is not.  This is a simple approach, and there may be a more optimal
+   policy but until a problem with this approach is discovered, simplest is probably best.
+
+   NOTE: In this case, the ordering produced by flush is parent-first only if you ignore
+   the leaves.  This is done as a matter of simplicity and there is only one (shaky)
+   justification.  When an atom commits, it flushes all leaf level nodes first, followed
+   by twigs, and so on.  With flushing done in this order, if flush is eventually called
+   on a non-leaf node it means that (somehow) we reached a point where all leaves are
+   clean and only internal nodes need to be flushed.  If that it the case, then it means
+   there were no leaves that were the parent-first preceder/follower of the parent.  This
+   is expected to be a rare case, which is why we do nothing special about it.  However,
+   memory pressure may pass an internal node to flush when there are still dirty leaf
+   nodes that need to be flushed, which could prove our original assumptions
+   "inoperative".  If this needs to be fixed, then scan_left/right should have
+   special checks for the non-leaf levels.  For example, instead of passing from a node to
+   the left neighbor, it should pass from the node to the left neighbor's rightmost
+   descendent (if dirty).
+
+*/
+
+/* UNIMPLEMENTED AS YET: REPACKING AND RESIZING.  We walk the tree in 4MB-16MB chunks, dirtying everything and putting
+   it into a transaction.  We tell the allocator to allocate the blocks as far as possible towards one end of the
+   logical device--the left (starting) end of the device if we are walking from left to right, the right end of the
+   device if we are walking from right to left.  We then make passes in alternating directions, and as we do this the
+   device becomes sorted such that tree order and block number order fully correlate.
+
+   Resizing is done by shifting everything either all the way to the left or all the way
+   to the right, and then reporting the last block.
+*/
+
+/* RELOCATE DECISIONS: The code makes a decision to relocate in several places.  This
+   descibes the policy from the highest level:
+
+   The FLUSH_RELOCATE_THRESHOLD parameter: If we count this many consecutive nodes on the
+   leaf level during flush-scan (right, left), then we unconditionally decide to relocate
+   leaf nodes.
+
+   Otherwise, there are two contexts in which we make a decision to relocate:
+
+   1. The REVERSE PARENT-FIRST context: Implemented in reverse_relocate_test().
+   During the initial stages of flush, after scan-right completes, we want to ask the
+   question: should we relocate this leaf node and thus dirty the parent node.  Then if
+   the node is a leftmost child its parent is its own parent-first preceder, thus we repeat
+   the question at the next level up, and so on.  In these cases we are moving in the
+   reverse-parent first direction.
+
+   There is another case which is considered the reverse direction, which comes at the end
+   of a twig in reverse_relocate_end_of_twig().  As we finish processing a twig we may
+   reach a point where there is a clean twig to the right with a dirty leftmost child.  In
+   this case, we may wish to relocate the child by testing if it should be relocated
+   relative to its parent.
+
+   2. The FORWARD PARENT-FIRST context: Testing for forward relocation is done in
+   allocate_znode.  What distinguishes the forward parent-first case from the
+   reverse-parent first case is that the preceder has already been allocated in the
+   forward case, whereas in the reverse case we don't know what the preceder is until we
+   finish "going in reverse".  That simplifies the forward case considerably, and there we
+   actually use the block allocator to determine whether, e.g., a block closer to the
+   preceder is available.
+*/
+
+/* SQUEEZE_LEFT_EDGE: Unimplemented idea for future consideration.  The idea is, once we
+   finish scan-left and find a starting point, if the parent's left neighbor is dirty then
+   squeeze the parent's left neighbor and the parent.  This may change the
+   flush-starting-node's parent.  Repeat until the child's parent is stable.  If the child
+   is a leftmost child, repeat this left-edge squeezing operation at the next level up.
+   Note that we cannot allocate extents during this or they will be out of parent-first
+   order.  There is also some difficult coordinate maintenence issues.  We can't do a tree
+   search to find coordinates again (because we hold locks), we have to determine them
+   from the two nodes being squeezed.  Looks difficult, but has potential to increase
+   space utilization. */
+
+/* Flush-scan helper functions. */
+static void scan_init(flush_scan * scan);
+static void scan_done(flush_scan * scan);
+
+/* Flush-scan algorithm. */
+static int scan_left(flush_scan * scan, flush_scan * right, jnode * node,
+                    unsigned limit);
+static int scan_right(flush_scan * scan, jnode * node, unsigned limit);
+static int scan_common(flush_scan * scan, flush_scan * other);
+static int scan_formatted(flush_scan * scan);
+static int scan_unformatted(flush_scan * scan, flush_scan * other);
+static int scan_by_coord(flush_scan * scan);
+
+/* Initial flush-point ancestor allocation. */
+static int alloc_pos_and_ancestors(flush_pos_t * pos);
+static int alloc_one_ancestor(const coord_t * coord, flush_pos_t * pos);
+static int set_preceder(const coord_t * coord_in, flush_pos_t * pos);
+
+/* Main flush algorithm.  Note on abbreviation: "squeeze and allocate" == "squalloc". */
+static int squalloc(flush_pos_t * pos);
+
+/* Flush squeeze implementation. */
+static int squeeze_right_non_twig(znode * left, znode * right);
+static int shift_one_internal_unit(znode * left, znode * right);
+
+/* Flush reverse parent-first relocation routines. */
+static int reverse_relocate_if_close_enough(const reiser4_block_nr * pblk,
+                                           const reiser4_block_nr * nblk);
+static int reverse_relocate_test(jnode * node, const coord_t * parent_coord,
+                                flush_pos_t * pos);
+static int reverse_relocate_check_dirty_parent(jnode * node,
+                                              const coord_t * parent_coord,
+                                              flush_pos_t * pos);
+
+/* Flush allocate write-queueing functions: */
+static int allocate_znode(znode * node, const coord_t * parent_coord,
+                         flush_pos_t * pos);
+static int allocate_znode_update(znode * node, const coord_t * parent_coord,
+                                flush_pos_t * pos);
+static int lock_parent_and_allocate_znode(znode *, flush_pos_t *);
+
+/* Flush helper functions: */
+static int jnode_lock_parent_coord(jnode * node,
+                                  coord_t * coord,
+                                  lock_handle * parent_lh,
+                                  load_count * parent_zh,
+                                  znode_lock_mode mode, int try);
+static int neighbor_in_slum(znode * node, lock_handle * right_lock, sideof side,
+                           znode_lock_mode mode, int check_dirty);
+static int znode_same_parents(znode * a, znode * b);
+
+static int znode_check_flushprepped(znode * node)
+{
+       return jnode_check_flushprepped(ZJNODE(node));
+}
+
+/* Flush position functions */
+static void pos_init(flush_pos_t * pos);
+static int pos_valid(flush_pos_t * pos);
+static void pos_done(flush_pos_t * pos);
+static int pos_stop(flush_pos_t * pos);
+
+/* check that @org is first jnode extent unit, if extent is unallocated,
+ * because all jnodes of unallocated extent are dirty and of the same atom. */
+#define checkchild(scan)                                               \
+assert("nikita-3435",                                                  \
+       ergo(scan->direction == LEFT_SIDE &&                            \
+            (scan->parent_coord.node->level == TWIG_LEVEL) &&           \
+           jnode_is_unformatted(scan->node) &&                         \
+           extent_is_unallocated(&scan->parent_coord),                 \
+           extent_unit_index(&scan->parent_coord) == index_jnode(scan->node)))
+
+/* This flush_cnt variable is used to track the number of concurrent flush operations,
+   useful for debugging.  It is initialized in txnmgr.c out of laziness (because flush has
+   no static initializer function...) */
+ON_DEBUG(atomic_t flush_cnt;
+    )
+
+/* check fs backing device for write congestion */
+static int check_write_congestion(void)
+{
+       struct super_block *sb;
+       struct backing_dev_info *bdi;
+
+       sb = reiser4_get_current_sb();
+       bdi = reiser4_get_super_fake(sb)->i_mapping->backing_dev_info;
+       return bdi_write_congested(bdi);
+}
+
+/* conditionally write flush queue */
+static int write_prepped_nodes(flush_pos_t * pos)
+{
+       int ret;
+
+       assert("zam-831", pos);
+       assert("zam-832", pos->fq);
+
+       if (!(pos->flags & JNODE_FLUSH_WRITE_BLOCKS))
+               return 0;
+
+       if (check_write_congestion())
+               return 0;
+
+       ret = reiser4_write_fq(pos->fq, pos->nr_written,
+                      WRITEOUT_SINGLE_STREAM | WRITEOUT_FOR_PAGE_RECLAIM);
+       return ret;
+}
+
+/* Proper release all flush pos. resources then move flush position to new
+   locked node */
+static void move_flush_pos(flush_pos_t * pos, lock_handle * new_lock,
+                          load_count * new_load, const coord_t * new_coord)
+{
+       assert("zam-857", new_lock->node == new_load->node);
+
+       if (new_coord) {
+               assert("zam-858", new_coord->node == new_lock->node);
+               coord_dup(&pos->coord, new_coord);
+       } else {
+               coord_init_first_unit(&pos->coord, new_lock->node);
+       }
+
+       if (pos->child) {
+               jput(pos->child);
+               pos->child = NULL;
+       }
+
+       move_load_count(&pos->load, new_load);
+       done_lh(&pos->lock);
+       move_lh(&pos->lock, new_lock);
+}
+
+/* delete empty node which link from the parent still exists. */
+static int delete_empty_node(znode * node)
+{
+       reiser4_key smallest_removed;
+
+       assert("zam-1019", node != NULL);
+       assert("zam-1020", node_is_empty(node));
+       assert("zam-1023", znode_is_wlocked(node));
+
+       return reiser4_delete_node(node, &smallest_removed, NULL, 1);
+}
+
+/* Prepare flush position for alloc_pos_and_ancestors() and squalloc() */
+static int prepare_flush_pos(flush_pos_t * pos, jnode * org)
+{
+       int ret;
+       load_count load;
+       lock_handle lock;
+
+       init_lh(&lock);
+       init_load_count(&load);
+
+       if (jnode_is_znode(org)) {
+               ret = longterm_lock_znode(&lock, JZNODE(org),
+                                         ZNODE_WRITE_LOCK, ZNODE_LOCK_HIPRI);
+               if (ret)
+                       return ret;
+
+               ret = incr_load_count_znode(&load, JZNODE(org));
+               if (ret)
+                       return ret;
+
+               pos->state =
+                   (jnode_get_level(org) ==
+                    LEAF_LEVEL) ? POS_ON_LEAF : POS_ON_INTERNAL;
+               move_flush_pos(pos, &lock, &load, NULL);
+       } else {
+               coord_t parent_coord;
+               ret = jnode_lock_parent_coord(org, &parent_coord, &lock,
+                                             &load, ZNODE_WRITE_LOCK, 0);
+               if (ret)
+                       goto done;
+               if (!item_is_extent(&parent_coord)) {
+                       /* file was converted to tail, org became HB, we found internal
+                          item */
+                       ret = -EAGAIN;
+                       goto done;
+               }
+
+               pos->state = POS_ON_EPOINT;
+               move_flush_pos(pos, &lock, &load, &parent_coord);
+               pos->child = jref(org);
+               if (extent_is_unallocated(&parent_coord)
+                   && extent_unit_index(&parent_coord) != index_jnode(org)) {
+                       /* @org is not first child of its parent unit. This may happen
+                          because longerm lock of its parent node was released between
+                          scan_left and scan_right. For now work around this having flush to repeat */
+                       ret = -EAGAIN;
+               }
+       }
+
+      done:
+       done_load_count(&load);
+       done_lh(&lock);
+       return ret;
+}
+
+/* TODO LIST (no particular order): */
+/* I have labelled most of the legitimate FIXME comments in this file with letters to
+   indicate which issue they relate to.  There are a few miscellaneous FIXMEs with
+   specific names mentioned instead that need to be inspected/resolved. */
+/* B. There is an issue described in reverse_relocate_test having to do with an
+   imprecise is_preceder? check having to do with partially-dirty extents.  The code that
+   sets preceder hints and computes the preceder is basically untested.  Careful testing
+   needs to be done that preceder calculations are done correctly, since if it doesn't
+   affect correctness we will not catch this stuff during regular testing. */
+/* C. EINVAL, E_DEADLOCK, E_NO_NEIGHBOR, ENOENT handling.  It is unclear which of these are
+   considered expected but unlikely conditions.  Flush currently returns 0 (i.e., success
+   but no progress, i.e., restart) whenever it receives any of these in jnode_flush().
+   Many of the calls that may produce one of these return values (i.e.,
+   longterm_lock_znode, reiser4_get_parent, reiser4_get_neighbor, ...) check some of these
+   values themselves and, for instance, stop flushing instead of resulting in a restart.
+   If any of these results are true error conditions then flush will go into a busy-loop,
+   as we noticed during testing when a corrupt tree caused find_child_ptr to return
+   ENOENT.  It needs careful thought and testing of corner conditions.
+*/
+/* D. Atomicity of flush_prep against deletion and flush concurrency.  Suppose a created
+   block is assigned a block number then early-flushed to disk.  It is dirtied again and
+   flush is called again.  Concurrently, that block is deleted, and the de-allocation of
+   its block number does not need to be deferred, since it is not part of the preserve set
+   (i.e., it didn't exist before the transaction).  I think there may be a race condition
+   where flush writes the dirty, created block after the non-deferred deallocated block
+   number is re-allocated, making it possible to write deleted data on top of non-deleted
+   data.  Its just a theory, but it needs to be thought out. */
+/* F. bio_alloc() failure is not handled gracefully. */
+/* G. Unallocated children. */
+/* H. Add a WANDERED_LIST to the atom to clarify the placement of wandered blocks. */
+/* I. Rename flush-scan to scan-point, (flush-pos to flush-point?) */
+
+/* JNODE_FLUSH: MAIN ENTRY POINT */
+/* This is the main entry point for flushing a jnode and its dirty neighborhood (dirty
+   neighborhood is named "slum").  Jnode_flush() is called if reiser4 has to write dirty
+   blocks to disk, it happens when Linux VM decides to reduce number of dirty pages or as
+   a part of transaction commit.
+
+   Our objective here is to prep and flush the slum the jnode belongs to. We want to
+   squish the slum together, and allocate the nodes in it as we squish because allocation
+   of children affects squishing of parents.
+
+   The "argument" @node tells flush where to start.  From there, flush finds the left edge
+   of the slum, and calls squalloc (in which nodes are squeezed and allocated).  To find a
+   "better place" to start squalloc first we perform a flush_scan.
+
+   Flush-scanning may be performed in both left and right directions, but for different
+   purposes.  When scanning to the left, we are searching for a node that precedes a
+   sequence of parent-first-ordered nodes which we will then flush in parent-first order.
+   During flush-scanning, we also take the opportunity to count the number of consecutive
+   leaf nodes.  If this number is past some threshold (FLUSH_RELOCATE_THRESHOLD), then we
+   make a decision to reallocate leaf nodes (thus favoring write-optimization).
+
+   Since the flush argument node can be anywhere in a sequence of dirty leaves, there may
+   also be dirty nodes to the right of the argument.  If the scan-left operation does not
+   count at least FLUSH_RELOCATE_THRESHOLD nodes then we follow it with a right-scan
+   operation to see whether there is, in fact, enough nodes to meet the relocate
+   threshold.  Each right- and left-scan operation uses a single flush_scan object.
+
+   After left-scan and possibly right-scan, we prepare a flush_position object with the
+   starting flush point or parent coordinate, which was determined using scan-left.
+
+   Next we call the main flush routine, squalloc, which iterates along the
+   leaf level, squeezing and allocating nodes (and placing them into the flush queue).
+
+   After squalloc returns we take extra steps to ensure that all the children
+   of the final twig node are allocated--this involves repeating squalloc
+   until we finish at a twig with no unallocated children.
+
+   Finally, we call flush_empty_queue to submit write-requests to disk.  If we encounter
+   any above-twig nodes during flush_empty_queue that still have unallocated children, we
+   flush_unprep them.
+
+   Flush treats several "failure" cases as non-failures, essentially causing them to start
+   over.  E_DEADLOCK is one example.  FIXME:(C) EINVAL, E_NO_NEIGHBOR, ENOENT: these should
+   probably be handled properly rather than restarting, but there are a bunch of cases to
+   audit.
+*/
+
+static int
+jnode_flush(jnode * node, long nr_to_write, long *nr_written,
+           flush_queue_t * fq, int flags)
+{
+       long ret = 0;
+       flush_scan *right_scan;
+       flush_scan *left_scan;
+       flush_pos_t *flush_pos;
+       int todo;
+       struct super_block *sb;
+       reiser4_super_info_data *sbinfo;
+       jnode *leftmost_in_slum = NULL;
+
+       assert("jmacd-76619", lock_stack_isclean(get_current_lock_stack()));
+       assert("nikita-3022", reiser4_schedulable());
+
+       assert("nikita-3185",
+              get_current_super_private()->delete_mutex_owner != current);
+
+       /* allocate right_scan, left_scan and flush_pos */
+       right_scan =
+           kmalloc(2 * sizeof(*right_scan) + sizeof(*flush_pos),
+                   reiser4_ctx_gfp_mask_get());
+       if (right_scan == NULL)
+               return RETERR(-ENOMEM);
+       left_scan = right_scan + 1;
+       flush_pos = (flush_pos_t *) (left_scan + 1);
+
+       sb = reiser4_get_current_sb();
+       sbinfo = get_super_private(sb);
+
+       /* Flush-concurrency debug code */
+#if REISER4_DEBUG
+       atomic_inc(&flush_cnt);
+#endif
+
+       reiser4_enter_flush(sb);
+
+       /* Initialize a flush position. */
+       pos_init(flush_pos);
+
+       flush_pos->nr_written = nr_written;
+       flush_pos->fq = fq;
+       flush_pos->flags = flags;
+       flush_pos->nr_to_write = nr_to_write;
+
+       scan_init(right_scan);
+       scan_init(left_scan);
+
+       /* First scan left and remember the leftmost scan position.  If the leftmost
+          position is unformatted we remember its parent_coord.  We scan until counting
+          FLUSH_SCAN_MAXNODES.
+
+          If starting @node is unformatted, at the beginning of left scan its
+          parent (twig level node, containing extent item) will be long term
+          locked and lock handle will be stored in the
+          @right_scan->parent_lock. This lock is used to start the rightward
+          scan without redoing the tree traversal (necessary to find parent)
+          and, hence, is kept during leftward scan. As a result, we have to
+          use try-lock when taking long term locks during the leftward scan.
+        */
+       ret = scan_left(left_scan, right_scan,
+                       node, sbinfo->flush.scan_maxnodes);
+       if (ret != 0)
+               goto failed;
+
+       leftmost_in_slum = jref(left_scan->node);
+       scan_done(left_scan);
+
+       /* Then possibly go right to decide if we will use a policy of relocating leaves.
+          This is only done if we did not scan past (and count) enough nodes during the
+          leftward scan.  If we do scan right, we only care to go far enough to establish
+          that at least FLUSH_RELOCATE_THRESHOLD number of nodes are being flushed.  The
+          scan limit is the difference between left_scan.count and the threshold. */
+
+       todo = sbinfo->flush.relocate_threshold - left_scan->count;
+       /* scan right is inherently deadlock prone, because we are
+        * (potentially) holding a lock on the twig node at this moment.
+        * FIXME: this is incorrect comment: lock is not held */
+       if (todo > 0) {
+               ret = scan_right(right_scan, node, (unsigned)todo);
+               if (ret != 0)
+                       goto failed;
+       }
+
+       /* Only the right-scan count is needed, release any rightward locks right away. */
+       scan_done(right_scan);
+
+       /* ... and the answer is: we should relocate leaf nodes if at least
+          FLUSH_RELOCATE_THRESHOLD nodes were found. */
+       flush_pos->leaf_relocate = JF_ISSET(node, JNODE_REPACK) ||
+           (left_scan->count + right_scan->count >=
+            sbinfo->flush.relocate_threshold);
+
+       /* Funny business here.  We set the 'point' in the flush_position at prior to
+          starting squalloc regardless of whether the first point is
+          formatted or unformatted.  Without this there would be an invariant, in the
+          rest of the code, that if the flush_position is unformatted then
+          flush_position->point is NULL and flush_position->parent_{lock,coord} is set,
+          and if the flush_position is formatted then flush_position->point is non-NULL
+          and no parent info is set.
+
+          This seems lazy, but it makes the initial calls to reverse_relocate_test
+          (which ask "is it the pos->point the leftmost child of its parent") much easier
+          because we know the first child already.  Nothing is broken by this, but the
+          reasoning is subtle.  Holding an extra reference on a jnode during flush can
+          cause us to see nodes with HEARD_BANSHEE during squalloc, because nodes are not
+          removed from sibling lists until they have zero reference count.  Flush would
+          never observe a HEARD_BANSHEE node on the left-edge of flush, nodes are only
+          deleted to the right.  So if nothing is broken, why fix it?
+
+          NOTE-NIKITA actually, flush can meet HEARD_BANSHEE node at any
+          point and in any moment, because of the concurrent file system
+          activity (for example, truncate). */
+
+       /* Check jnode state after flush_scan completed. Having a lock on this
+          node or its parent (in case of unformatted) helps us in case of
+          concurrent flushing. */
+       if (jnode_check_flushprepped(leftmost_in_slum)
+           && !jnode_convertible(leftmost_in_slum)) {
+               ret = 0;
+               goto failed;
+       }
+
+       /* Now setup flush_pos using scan_left's endpoint. */
+       ret = prepare_flush_pos(flush_pos, leftmost_in_slum);
+       if (ret)
+               goto failed;
+
+       if (znode_get_level(flush_pos->coord.node) == LEAF_LEVEL
+           && node_is_empty(flush_pos->coord.node)) {
+               znode *empty = flush_pos->coord.node;
+
+               assert("zam-1022", !ZF_ISSET(empty, JNODE_HEARD_BANSHEE));
+               ret = delete_empty_node(empty);
+               goto failed;
+       }
+
+       if (jnode_check_flushprepped(leftmost_in_slum)
+           && !jnode_convertible(leftmost_in_slum)) {
+               ret = 0;
+               goto failed;
+       }
+
+       /* Set pos->preceder and (re)allocate pos and its ancestors if it is needed  */
+       ret = alloc_pos_and_ancestors(flush_pos);
+       if (ret)
+               goto failed;
+
+       /* Do the main rightward-bottom-up squeeze and allocate loop. */
+       ret = squalloc(flush_pos);
+       pos_stop(flush_pos);
+       if (ret)
+               goto failed;
+
+       /* FIXME_NFQUCMPD: Here, handle the twig-special case for unallocated children.
+          First, the pos_stop() and pos_valid() routines should be modified
+          so that pos_stop() sets a flush_position->stop flag to 1 without
+          releasing the current position immediately--instead release it in
+          pos_done().  This is a better implementation than the current one anyway.
+
+          It is not clear that all fields of the flush_position should not be released,
+          but at the very least the parent_lock, parent_coord, and parent_load should
+          remain held because they are hold the last twig when pos_stop() is
+          called.
+
+          When we reach this point in the code, if the parent_coord is set to after the
+          last item then we know that flush reached the end of a twig (and according to
+          the new flush queueing design, we will return now).  If parent_coord is not
+          past the last item, we should check if the current twig has any unallocated
+          children to the right (we are not concerned with unallocated children to the
+          left--in that case the twig itself should not have been allocated).  If the
+          twig has unallocated children to the right, set the parent_coord to that
+          position and then repeat the call to squalloc.
+
+          Testing for unallocated children may be defined in two ways: if any internal
+          item has a fake block number, it is unallocated; if any extent item is
+          unallocated then all of its children are unallocated.  But there is a more
+          aggressive approach: if there are any dirty children of the twig to the right
+          of the current position, we may wish to relocate those nodes now.  Checking for
+          potential relocation is more expensive as it requires knowing whether there are
+          any dirty children that are not unallocated.  The extent_needs_allocation
+          should be used after setting the correct preceder.
+
+          When we reach the end of a twig at this point in the code, if the flush can
+          continue (when the queue is ready) it will need some information on the future
+          starting point.  That should be stored away in the flush_handle using a seal, I
+          believe.  Holding a jref() on the future starting point may break other code
+          that deletes that node.
+        */
+
+       /* FIXME_NFQUCMPD: Also, we don't want to do any flushing when flush is called
+          above the twig level.  If the VM calls flush above the twig level, do nothing
+          and return (but figure out why this happens).  The txnmgr should be modified to
+          only flush its leaf-level dirty list.  This will do all the necessary squeeze
+          and allocate steps but leave unallocated branches and possibly unallocated
+          twigs (when the twig's leftmost child is not dirty).  After flushing the leaf
+          level, the remaining unallocated nodes should be given write-optimized
+          locations.  (Possibly, the remaining unallocated twigs should be allocated just
+          before their leftmost child.)
+        */
+
+       /* Any failure reaches this point. */
+      failed:
+
+       switch (ret) {
+       case -E_REPEAT:
+       case -EINVAL:
+       case -E_DEADLOCK:
+       case -E_NO_NEIGHBOR:
+       case -ENOENT:
+               /* FIXME(C): Except for E_DEADLOCK, these should probably be handled properly
+                  in each case.  They already are handled in many cases. */
+               /* Something bad happened, but difficult to avoid...  Try again! */
+               ret = 0;
+       }
+
+       if (leftmost_in_slum)
+               jput(leftmost_in_slum);
+
+       pos_done(flush_pos);
+       scan_done(left_scan);
+       scan_done(right_scan);
+       kfree(right_scan);
+
+       ON_DEBUG(atomic_dec(&flush_cnt));
+
+       reiser4_leave_flush(sb);
+
+       return ret;
+}
+
+/* The reiser4 flush subsystem can be turned into "rapid flush mode" means that
+ * flusher should submit all prepped nodes immediately without keeping them in
+ * flush queues for long time.  The reason for rapid flush mode is to free
+ * memory as fast as possible. */
+
+#if REISER4_USE_RAPID_FLUSH
+
+/**
+ * submit all prepped nodes if rapid flush mode is set,
+ * turn rapid flush mode off.
+ */
+
+static int rapid_flush(flush_pos_t * pos)
+{
+       if (!wbq_available())
+               return 0;
+
+       return write_prepped_nodes(pos);
+}
+
+#else
+
+#define rapid_flush(pos) (0)
+
+#endif                         /* REISER4_USE_RAPID_FLUSH */
+
+static jnode *find_flush_start_jnode(jnode *start, txn_atom *atom,
+                                    flush_queue_t *fq, int *nr_queued,
+                                    int flags)
+{
+       jnode * node;
+
+       if (start != NULL) {
+               spin_lock_jnode(start);
+               if (!jnode_is_flushprepped(start)) {
+                       assert("zam-1056", start->atom == atom);
+                       node = start;
+                       goto enter;
+               }
+               spin_unlock_jnode(start);
+       }
+       /*
+        * In this loop we process all already prepped (RELOC or OVRWR) and dirtied again
+        * nodes. The atom spin lock is not released until all dirty nodes processed or
+        * not prepped node found in the atom dirty lists.
+        */
+       while ((node = find_first_dirty_jnode(atom, flags))) {
+               spin_lock_jnode(node);
+       enter:
+               assert("zam-881", JF_ISSET(node, JNODE_DIRTY));
+               assert("zam-898", !JF_ISSET(node, JNODE_OVRWR));
+
+               if (JF_ISSET(node, JNODE_WRITEBACK)) {
+                       /* move node to the end of atom's writeback list */
+                       list_move_tail(&node->capture_link, ATOM_WB_LIST(atom));
+
+                       /*
+                        * jnode is not necessarily on dirty list: if it was dirtied when
+                        * it was on flush queue - it does not get moved to dirty list
+                        */
+                       ON_DEBUG(count_jnode(atom, node, NODE_LIST(node),
+                                            WB_LIST, 1));
+
+               } else if (jnode_is_znode(node)
+                          && znode_above_root(JZNODE(node))) {
+                       /*
+                        * A special case for znode-above-root.  The above-root (fake)
+                        * znode is captured and dirtied when the tree height changes or
+                        * when the root node is relocated.  This causes atoms to fuse so
+                        * that changes at the root are serialized.  However, this node is
+                        * never flushed.  This special case used to be in lock.c to
+                        * prevent the above-root node from ever being captured, but now
+                        * that it is captured we simply prevent it from flushing.  The
+                        * log-writer code relies on this to properly log superblock
+                        * modifications of the tree height.
+                        */
+                       jnode_make_wander_nolock(node);
+               } else if (JF_ISSET(node, JNODE_RELOC)) {
+                       queue_jnode(fq, node);
+                       ++(*nr_queued);
+               } else
+                       break;
+
+               spin_unlock_jnode(node);
+       }
+       return node;
+}
+
+/* Flush some nodes of current atom, usually slum, return -E_REPEAT if there are more nodes
+ * to flush, return 0 if atom's dirty lists empty and keep current atom locked, return
+ * other errors as they are. */
+int
+flush_current_atom(int flags, long nr_to_write, long *nr_submitted,
+                  txn_atom ** atom, jnode *start)
+{
+       reiser4_super_info_data *sinfo = get_current_super_private();
+       flush_queue_t *fq = NULL;
+       jnode *node;
+       int nr_queued;
+       int ret;
+
+       assert("zam-889", atom != NULL && *atom != NULL);
+       assert_spin_locked(&((*atom)->alock));
+       assert("zam-892", get_current_context()->trans->atom == *atom);
+
+       nr_to_write = LONG_MAX;
+       while (1) {
+               ret = reiser4_fq_by_atom(*atom, &fq);
+               if (ret != -E_REPEAT)
+                       break;
+               *atom = get_current_atom_locked();
+       }
+       if (ret)
+               return ret;
+
+       assert_spin_locked(&((*atom)->alock));
+
+       /* parallel flushers limit */
+       if (sinfo->tmgr.atom_max_flushers != 0) {
+               while ((*atom)->nr_flushers >= sinfo->tmgr.atom_max_flushers) {
+                       /* An reiser4_atom_send_event() call is inside
+                          reiser4_fq_put_nolock() which is called when flush is
+                          finished and nr_flushers is decremented. */
+                       reiser4_atom_wait_event(*atom);
+                       *atom = get_current_atom_locked();
+               }
+       }
+
+       /* count ourself as a flusher */
+       (*atom)->nr_flushers++;
+
+       writeout_mode_enable();
+
+       nr_queued = 0;
+       node = find_flush_start_jnode(start, *atom, fq, &nr_queued, flags);
+
+       if (node == NULL) {
+               if (nr_queued == 0) {
+                       (*atom)->nr_flushers--;
+                       reiser4_fq_put_nolock(fq);
+                       reiser4_atom_send_event(*atom);
+                       /* current atom remains locked */
+                       writeout_mode_disable();
+                       return 0;
+               }
+               spin_unlock_atom(*atom);
+       } else {
+               jref(node);
+               BUG_ON((*atom)->super != node->tree->super);
+               spin_unlock_atom(*atom);
+               spin_unlock_jnode(node);
+               BUG_ON(nr_to_write == 0);
+               ret = jnode_flush(node, nr_to_write, nr_submitted, fq, flags);
+               jput(node);
+       }
+
+       ret =
+           reiser4_write_fq(fq, nr_submitted,
+                    WRITEOUT_SINGLE_STREAM | WRITEOUT_FOR_PAGE_RECLAIM);
+
+       *atom = get_current_atom_locked();
+       (*atom)->nr_flushers--;
+       reiser4_fq_put_nolock(fq);
+       reiser4_atom_send_event(*atom);
+       spin_unlock_atom(*atom);
+
+       writeout_mode_disable();
+
+       if (ret == 0)
+               ret = -E_REPEAT;
+
+       return ret;
+}
+
+/* REVERSE PARENT-FIRST RELOCATION POLICIES */
+
+/* This implements the is-it-close-enough-to-its-preceder? test for relocation in the
+   reverse parent-first relocate context.  Here all we know is the preceder and the block
+   number.  Since we are going in reverse, the preceder may still be relocated as well, so
+   we can't ask the block allocator "is there a closer block available to relocate?" here.
+   In the _forward_ parent-first relocate context (not here) we actually call the block
+   allocator to try and find a closer location. */
+static int
+reverse_relocate_if_close_enough(const reiser4_block_nr * pblk,
+                                const reiser4_block_nr * nblk)
+{
+       reiser4_block_nr dist;
+
+       assert("jmacd-7710", *pblk != 0 && *nblk != 0);
+       assert("jmacd-7711", !reiser4_blocknr_is_fake(pblk));
+       assert("jmacd-7712", !reiser4_blocknr_is_fake(nblk));
+
+       /* Distance is the absolute value. */
+       dist = (*pblk > *nblk) ? (*pblk - *nblk) : (*nblk - *pblk);
+
+       /* If the block is less than FLUSH_RELOCATE_DISTANCE blocks away from its preceder
+          block, do not relocate. */
+       if (dist <= get_current_super_private()->flush.relocate_distance) {
+               return 0;
+       }
+
+       return 1;
+}
+
+/* This function is a predicate that tests for relocation.  Always called in the
+   reverse-parent-first context, when we are asking whether the current node should be
+   relocated in order to expand the flush by dirtying the parent level (and thus
+   proceeding to flush that level).  When traversing in the forward parent-first direction
+   (not here), relocation decisions are handled in two places: allocate_znode() and
+   extent_needs_allocation(). */
+static int
+reverse_relocate_test(jnode * node, const coord_t * parent_coord,
+                     flush_pos_t * pos)
+{
+       reiser4_block_nr pblk = 0;
+       reiser4_block_nr nblk = 0;
+
+       assert("jmacd-8989", !jnode_is_root(node));
+
+       /*
+        * This function is called only from the
+        * reverse_relocate_check_dirty_parent() and only if the parent
+        * node is clean. This implies that the parent has the real (i.e., not
+        * fake) block number, and, so does the child, because otherwise the
+        * parent would be dirty.
+        */
+
+       /* New nodes are treated as if they are being relocated. */
+       if (JF_ISSET (node, JNODE_CREATED) ||
+           (pos->leaf_relocate && jnode_get_level(node) == LEAF_LEVEL)) {
+               return 1;
+       }
+
+       /* Find the preceder.  FIXME(B): When the child is an unformatted, previously
+          existing node, the coord may be leftmost even though the child is not the
+          parent-first preceder of the parent.  If the first dirty node appears somewhere
+          in the middle of the first extent unit, this preceder calculation is wrong.
+          Needs more logic in here. */
+       if (coord_is_leftmost_unit(parent_coord)) {
+               pblk = *znode_get_block(parent_coord->node);
+       } else {
+               pblk = pos->preceder.blk;
+       }
+       check_preceder(pblk);
+
+       /* If (pblk == 0) then the preceder isn't allocated or isn't known: relocate. */
+       if (pblk == 0) {
+               return 1;
+       }
+
+       nblk = *jnode_get_block(node);
+
+       if (reiser4_blocknr_is_fake(&nblk))
+               /* child is unallocated, mark parent dirty */
+               return 1;
+
+       return reverse_relocate_if_close_enough(&pblk, &nblk);
+}
+
+/* This function calls reverse_relocate_test to make a reverse-parent-first
+   relocation decision and then, if yes, it marks the parent dirty. */
+static int
+reverse_relocate_check_dirty_parent(jnode * node, const coord_t * parent_coord,
+                                   flush_pos_t * pos)
+{
+       int ret;
+
+       if (!JF_ISSET(ZJNODE(parent_coord->node), JNODE_DIRTY)) {
+
+               ret = reverse_relocate_test(node, parent_coord, pos);
+               if (ret < 0) {
+                       return ret;
+               }
+
+               /* FIXME-ZAM
+                  if parent is already relocated - we do not want to grab space, right? */
+               if (ret == 1) {
+                       int grabbed;
+
+                       grabbed = get_current_context()->grabbed_blocks;
+                       if (reiser4_grab_space_force((__u64) 1, BA_RESERVED) !=
+                           0)
+                               reiser4_panic("umka-1250",
+                                             "No space left during flush.");
+
+                       assert("jmacd-18923",
+                              znode_is_write_locked(parent_coord->node));
+                       znode_make_dirty(parent_coord->node);
+                       grabbed2free_mark(grabbed);
+               }
+       }
+
+       return 0;
+}
+
+/* INITIAL ALLOCATE ANCESTORS STEP (REVERSE PARENT-FIRST ALLOCATION BEFORE FORWARD
+   PARENT-FIRST LOOP BEGINS) */
+
+/* Get the leftmost child for given coord. */
+static int get_leftmost_child_of_unit(const coord_t * coord, jnode ** child)
+{
+       int ret;
+
+       ret = item_utmost_child(coord, LEFT_SIDE, child);
+
+       if (ret)
+               return ret;
+
+       if (IS_ERR(*child))
+               return PTR_ERR(*child);
+
+       return 0;
+}
+
+/* This step occurs after the left- and right-scans are completed, before starting the
+   forward parent-first traversal.  Here we attempt to allocate ancestors of the starting
+   flush point, which means continuing in the reverse parent-first direction to the
+   parent, grandparent, and so on (as long as the child is a leftmost child).  This
+   routine calls a recursive process, alloc_one_ancestor, which does the real work,
+   except there is special-case handling here for the first ancestor, which may be a twig.
+   At each level (here and alloc_one_ancestor), we check for relocation and then, if
+   the child is a leftmost child, repeat at the next level.  On the way back down (the
+   recursion), we allocate the ancestors in parent-first order. */
+static int alloc_pos_and_ancestors(flush_pos_t * pos)
+{
+       int ret = 0;
+       lock_handle plock;
+       load_count pload;
+       coord_t pcoord;
+
+       if (znode_check_flushprepped(pos->lock.node))
+               return 0;
+
+       coord_init_invalid(&pcoord, NULL);
+       init_lh(&plock);
+       init_load_count(&pload);
+
+       if (pos->state == POS_ON_EPOINT) {
+               /* a special case for pos on twig level, where we already have
+                  a lock on parent node. */
+               /* The parent may not be dirty, in which case we should decide
+                  whether to relocate the child now. If decision is made to
+                  relocate the child, the parent is marked dirty. */
+               ret =
+                   reverse_relocate_check_dirty_parent(pos->child, &pos->coord,
+                                                       pos);
+               if (ret)
+                       goto exit;
+
+               /* FIXME_NFQUCMPD: We only need to allocate the twig (if child
+                  is leftmost) and the leaf/child, so recursion is not needed.
+                  Levels above the twig will be allocated for
+                  write-optimization before the transaction commits.  */
+
+               /* Do the recursive step, allocating zero or more of our
+                * ancestors. */
+               ret = alloc_one_ancestor(&pos->coord, pos);
+
+       } else {
+               if (!znode_is_root(pos->lock.node)) {
+                       /* all formatted nodes except tree root */
+                       ret =
+                           reiser4_get_parent(&plock, pos->lock.node,
+                                              ZNODE_WRITE_LOCK);
+                       if (ret)
+                               goto exit;
+
+                       ret = incr_load_count_znode(&pload, plock.node);
+                       if (ret)
+                               goto exit;
+
+                       ret =
+                           find_child_ptr(plock.node, pos->lock.node, &pcoord);
+                       if (ret)
+                               goto exit;
+
+                       ret =
+                           reverse_relocate_check_dirty_parent(ZJNODE
+                                                               (pos->lock.
+                                                                node), &pcoord,
+                                                               pos);
+                       if (ret)
+                               goto exit;
+
+                       ret = alloc_one_ancestor(&pcoord, pos);
+                       if (ret)
+                               goto exit;
+               }
+
+               ret = allocate_znode(pos->lock.node, &pcoord, pos);
+       }
+      exit:
+       done_load_count(&pload);
+       done_lh(&plock);
+       return ret;
+}
+
+/* This is the recursive step described in alloc_pos_and_ancestors, above.  Ignoring the
+   call to set_preceder, which is the next function described, this checks if the
+   child is a leftmost child and returns if it is not.  If the child is a leftmost child
+   it checks for relocation, possibly dirtying the parent.  Then it performs the recursive
+   step. */
+static int alloc_one_ancestor(const coord_t * coord, flush_pos_t * pos)
+{
+       int ret = 0;
+       lock_handle alock;
+       load_count aload;
+       coord_t acoord;
+
+       /* As we ascend at the left-edge of the region to flush, take this opportunity at
+          the twig level to find our parent-first preceder unless we have already set
+          it. */
+       if (pos->preceder.blk == 0) {
+               ret = set_preceder(coord, pos);
+               if (ret != 0)
+                       return ret;
+       }
+
+       /* If the ancestor is clean or already allocated, or if the child is not a
+          leftmost child, stop going up, even leaving coord->node not flushprepped. */
+       if (znode_check_flushprepped(coord->node)
+           || !coord_is_leftmost_unit(coord))
+               return 0;
+
+       init_lh(&alock);
+       init_load_count(&aload);
+       coord_init_invalid(&acoord, NULL);
+
+       /* Only ascend to the next level if it is a leftmost child, but write-lock the
+          parent in case we will relocate the child. */
+       if (!znode_is_root(coord->node)) {
+
+               ret =
+                   jnode_lock_parent_coord(ZJNODE(coord->node), &acoord,
+                                           &alock, &aload, ZNODE_WRITE_LOCK,
+                                           0);
+               if (ret != 0) {
+                       /* FIXME(C): check EINVAL, E_DEADLOCK */
+                       goto exit;
+               }
+
+               ret =
+                   reverse_relocate_check_dirty_parent(ZJNODE(coord->node),
+                                                       &acoord, pos);
+               if (ret != 0) {
+                       goto exit;
+               }
+
+               /* Recursive call. */
+               if (!znode_check_flushprepped(acoord.node)) {
+                       ret = alloc_one_ancestor(&acoord, pos);
+                       if (ret)
+                               goto exit;
+               }
+       }
+
+       /* Note: we call allocate with the parent write-locked (except at the root) in
+          case we relocate the child, in which case it will modify the parent during this
+          call. */
+       ret = allocate_znode(coord->node, &acoord, pos);
+
+      exit:
+       done_load_count(&aload);
+       done_lh(&alock);
+       return ret;
+}
+
+/* During the reverse parent-first alloc_pos_and_ancestors process described above there is
+   a call to this function at the twig level.  During alloc_pos_and_ancestors we may ask:
+   should this node be relocated (in reverse parent-first context)?  We repeat this
+   process as long as the child is the leftmost child, eventually reaching an ancestor of
+   the flush point that is not a leftmost child.  The preceder of that ancestors, which is
+   not a leftmost child, is actually on the leaf level.  The preceder of that block is the
+   left-neighbor of the flush point.  The preceder of that block is the rightmost child of
+   the twig on the left.  So, when alloc_pos_and_ancestors passes upward through the twig
+   level, it stops momentarily to remember the block of the rightmost child of the twig on
+   the left and sets it to the flush_position's preceder_hint.
+
+   There is one other place where we may set the flush_position's preceder hint, which is
+   during scan-left.
+*/
+static int set_preceder(const coord_t * coord_in, flush_pos_t * pos)
+{
+       int ret;
+       coord_t coord;
+       lock_handle left_lock;
+       load_count left_load;
+
+       coord_dup(&coord, coord_in);
+
+       init_lh(&left_lock);
+       init_load_count(&left_load);
+
+       /* FIXME(B): Same FIXME as in "Find the preceder" in reverse_relocate_test.
+          coord_is_leftmost_unit is not the right test if the unformatted child is in the
+          middle of the first extent unit. */
+       if (!coord_is_leftmost_unit(&coord)) {
+               coord_prev_unit(&coord);
+       } else {
+               ret =
+                   reiser4_get_left_neighbor(&left_lock, coord.node,
+                                             ZNODE_READ_LOCK, GN_SAME_ATOM);
+               if (ret) {
+                       /* If we fail for any reason it doesn't matter because the
+                          preceder is only a hint.  We are low-priority at this point, so
+                          this must be the case. */
+                       if (ret == -E_REPEAT || ret == -E_NO_NEIGHBOR ||
+                           ret == -ENOENT || ret == -EINVAL
+                           || ret == -E_DEADLOCK) {
+                               ret = 0;
+                       }
+                       goto exit;
+               }
+
+               ret = incr_load_count_znode(&left_load, left_lock.node);
+               if (ret)
+                       goto exit;
+
+               coord_init_last_unit(&coord, left_lock.node);
+       }
+
+       ret =
+           item_utmost_child_real_block(&coord, RIGHT_SIDE,
+                                        &pos->preceder.blk);
+      exit:
+       check_preceder(pos->preceder.blk);
+       done_load_count(&left_load);
+       done_lh(&left_lock);
+       return ret;
+}
+
+/* MAIN SQUEEZE AND ALLOCATE LOOP (THREE BIG FUNCTIONS) */
+
+/* This procedure implements the outer loop of the flush algorithm.  To put this in
+   context, here is the general list of steps taken by the flush routine as a whole:
+
+   1. Scan-left
+   2. Scan-right (maybe)
+   3. Allocate initial flush position and its ancestors
+   4. <handle extents>
+   5. <squeeze and next position and its ancestors to-the-right,
+       then update position to-the-right>
+   6. <repeat from #4 until flush is stopped>
+
+   This procedure implements the loop in steps 4 through 6 in the above listing.
+
+   Step 4: if the current flush position is an extent item (position on the twig level),
+   it allocates the extent (allocate_extent_item_in_place) then shifts to the next
+   coordinate.  If the next coordinate's leftmost child needs flushprep, we will continue.
+   If the next coordinate is an internal item, we descend back to the leaf level,
+   otherwise we repeat a step #4 (labeled ALLOC_EXTENTS below).  If the "next coordinate"
+   brings us past the end of the twig level, then we call
+   reverse_relocate_end_of_twig to possibly dirty the next (right) twig, prior to
+   step #5 which moves to the right.
+
+   Step 5: calls squalloc_changed_ancestors, which initiates a recursive call up the
+   tree to allocate any ancestors of the next-right flush position that are not also
+   ancestors of the current position.  Those ancestors (in top-down order) are the next in
+   parent-first order.  We squeeze adjacent nodes on the way up until the right node and
+   current node share the same parent, then allocate on the way back down.  Finally, this
+   step sets the flush position to the next-right node.  Then repeat steps 4 and 5.
+*/
+
+/* SQUEEZE CODE */
+
+/* squalloc_right_twig helper function, cut a range of extent items from
+   cut node to->node from the beginning up to coord @to. */
+static int squalloc_right_twig_cut(coord_t * to, reiser4_key * to_key,
+                                  znode * left)
+{
+       coord_t from;
+       reiser4_key from_key;
+
+       coord_init_first_unit(&from, to->node);
+       item_key_by_coord(&from, &from_key);
+
+       return cut_node_content(&from, to, &from_key, to_key, NULL);
+}
+
+/* Copy as much of the leading extents from @right to @left, allocating
+   unallocated extents as they are copied.  Returns SQUEEZE_TARGET_FULL or
+   SQUEEZE_SOURCE_EMPTY when no more can be shifted.  If the next item is an
+   internal item it calls shift_one_internal_unit and may then return
+   SUBTREE_MOVED. */
+static int squeeze_right_twig(znode * left, znode * right, flush_pos_t * pos)
+{
+       int ret = SUBTREE_MOVED;
+       coord_t coord;          /* used to iterate over items */
+       reiser4_key stop_key;
+
+       assert("jmacd-2008", !node_is_empty(right));
+       coord_init_first_unit(&coord, right);
+
+       /* FIXME: can be optimized to cut once */
+       while (!node_is_empty(coord.node) && item_is_extent(&coord)) {
+               ON_DEBUG(void *vp);
+
+               assert("vs-1468", coord_is_leftmost_unit(&coord));
+               ON_DEBUG(vp = shift_check_prepare(left, coord.node));
+
+               /* stop_key is used to find what was copied and what to cut */
+               stop_key = *reiser4_min_key();
+               ret = squalloc_extent(left, &coord, pos, &stop_key);
+               if (ret != SQUEEZE_CONTINUE) {
+                       ON_DEBUG(kfree(vp));
+                       break;
+               }
+               assert("vs-1465", !keyeq(&stop_key, reiser4_min_key()));
+
+               /* Helper function to do the cutting. */
+               set_key_offset(&stop_key, get_key_offset(&stop_key) - 1);
+               check_me("vs-1466",
+                        squalloc_right_twig_cut(&coord, &stop_key, left) == 0);
+
+               ON_DEBUG(shift_check(vp, left, coord.node));
+       }
+
+       if (node_is_empty(coord.node))
+               ret = SQUEEZE_SOURCE_EMPTY;
+
+       if (ret == SQUEEZE_TARGET_FULL) {
+               goto out;
+       }
+
+       if (node_is_empty(right)) {
+               /* The whole right node was copied into @left. */
+               assert("vs-464", ret == SQUEEZE_SOURCE_EMPTY);
+               goto out;
+       }
+
+       coord_init_first_unit(&coord, right);
+
+       if (!item_is_internal(&coord)) {
+               /* we do not want to squeeze anything else to left neighbor because "slum"
+                  is over */
+               ret = SQUEEZE_TARGET_FULL;
+               goto out;
+       }
+       assert("jmacd-433", item_is_internal(&coord));
+
+       /* Shift an internal unit.  The child must be allocated before shifting any more
+          extents, so we stop here. */
+       ret = shift_one_internal_unit(left, right);
+
+      out:
+       assert("jmacd-8612", ret < 0 || ret == SQUEEZE_TARGET_FULL
+              || ret == SUBTREE_MOVED || ret == SQUEEZE_SOURCE_EMPTY);
+
+       if (ret == SQUEEZE_TARGET_FULL) {
+               /* We submit prepped nodes here and expect that this @left twig
+                * will not be modified again during this jnode_flush() call. */
+               int ret1;
+
+               /* NOTE: seems like io is done under long term locks. */
+               ret1 = write_prepped_nodes(pos);
+               if (ret1 < 0)
+                       return ret1;
+       }
+
+       return ret;
+}
+
+#if REISER4_DEBUG
+static void item_convert_invariant(flush_pos_t * pos)
+{
+       assert("edward-1225", coord_is_existing_item(&pos->coord));
+       if (chaining_data_present(pos)) {
+               item_plugin *iplug = item_convert_plug(pos);
+
+               assert("edward-1000",
+                      iplug == item_plugin_by_coord(&pos->coord));
+               assert("edward-1001", iplug->f.convert != NULL);
+       } else
+               assert("edward-1226", pos->child == NULL);
+}
+#else
+
+#define item_convert_invariant(pos) noop
+
+#endif
+
+/* Scan node items starting from the first one and apply for each
+   item its flush ->convert() method (if any). This method may
+   resize/kill the item so the tree will be changed.
+*/
+static int convert_node(flush_pos_t * pos, znode * node)
+{
+       int ret = 0;
+       item_plugin *iplug;
+
+       assert("edward-304", pos != NULL);
+       assert("edward-305", pos->child == NULL);
+       assert("edward-475", znode_convertible(node));
+       assert("edward-669", znode_is_wlocked(node));
+       assert("edward-1210", !node_is_empty(node));
+
+       if (znode_get_level(node) != LEAF_LEVEL)
+               /* unsupported */
+               goto exit;
+
+       coord_init_first_unit(&pos->coord, node);
+
+       while (1) {
+               ret = 0;
+               coord_set_to_left(&pos->coord);
+               item_convert_invariant(pos);
+
+               iplug = item_plugin_by_coord(&pos->coord);
+               assert("edward-844", iplug != NULL);
+
+               if (iplug->f.convert) {
+                       ret = iplug->f.convert(pos);
+                       if (ret)
+                               goto exit;
+               }
+               assert("edward-307", pos->child == NULL);
+
+               if (coord_next_item(&pos->coord)) {
+                       /* node is over */
+
+                       if (!chaining_data_present(pos))
+                               /* finished this node */
+                               break;
+                       if (should_chain_next_node(pos)) {
+                               /* go to next node */
+                               move_chaining_data(pos, 0 /* to next node */ );
+                               break;
+                       }
+                       /* repeat this node */
+                       move_chaining_data(pos, 1 /* this node */ );
+                       continue;
+               }
+               /* Node is not over.
+                  Check if there is attached convert data.
+                  If so roll one item position back and repeat
+                  on this node
+                */
+               if (chaining_data_present(pos)) {
+
+                       if (iplug != item_plugin_by_coord(&pos->coord))
+                               set_item_convert_count(pos, 0);
+
+                       ret = coord_prev_item(&pos->coord);
+                       assert("edward-1003", !ret);
+
+                       move_chaining_data(pos, 1 /* this node */ );
+               }
+       }
+       JF_CLR(ZJNODE(node), JNODE_CONVERTIBLE);
+       znode_make_dirty(node);
+      exit:
+       assert("edward-1004", !ret);
+       return ret;
+}
+
+/* Squeeze and allocate the right neighbor.  This is called after @left and
+   its current children have been squeezed and allocated already.  This
+   procedure's job is to squeeze and items from @right to @left.
+
+   If at the leaf level, use the shift_everything_left memcpy-optimized
+   version of shifting (squeeze_right_leaf).
+
+   If at the twig level, extents are allocated as they are shifted from @right
+   to @left (squalloc_right_twig).
+
+   At any other level, shift one internal item and return to the caller
+   (squalloc_parent_first) so that the shifted-subtree can be processed in
+   parent-first order.
+
+   When unit of internal item is moved, squeezing stops and SUBTREE_MOVED is
+   returned.  When all content of @right is squeezed, SQUEEZE_SOURCE_EMPTY is
+   returned.  If nothing can be moved into @left anymore, SQUEEZE_TARGET_FULL
+   is returned.
+*/
+
+static int squeeze_right_neighbor(flush_pos_t * pos, znode * left,
+                                 znode * right)
+{
+       int ret;
+
+       /* FIXME it is possible to see empty hasn't-heard-banshee node in a
+        * tree owing to error (for example, ENOSPC) in write */
+       /* assert("jmacd-9321", !node_is_empty(left)); */
+       assert("jmacd-9322", !node_is_empty(right));
+       assert("jmacd-9323", znode_get_level(left) == znode_get_level(right));
+
+       switch (znode_get_level(left)) {
+       case TWIG_LEVEL:
+               /* Shift with extent allocating until either an internal item
+                  is encountered or everything is shifted or no free space
+                  left in @left */
+               ret = squeeze_right_twig(left, right, pos);
+               break;
+
+       default:
+               /* All other levels can use shift_everything until we implement per-item
+                  flush plugins. */
+               ret = squeeze_right_non_twig(left, right);
+               break;
+       }
+
+       assert("jmacd-2011", (ret < 0 ||
+                             ret == SQUEEZE_SOURCE_EMPTY
+                             || ret == SQUEEZE_TARGET_FULL
+                             || ret == SUBTREE_MOVED));
+       return ret;
+}
+
+static int squeeze_right_twig_and_advance_coord(flush_pos_t * pos,
+                                               znode * right)
+{
+       int ret;
+
+       ret = squeeze_right_twig(pos->lock.node, right, pos);
+       if (ret < 0)
+               return ret;
+       if (ret > 0) {
+               coord_init_after_last_item(&pos->coord, pos->lock.node);
+               return ret;
+       }
+
+       coord_init_last_unit(&pos->coord, pos->lock.node);
+       return 0;
+}
+
+/* forward declaration */
+static int squalloc_upper_levels(flush_pos_t *, znode *, znode *);
+
+/* do a fast check for "same parents" condition before calling
+ * squalloc_upper_levels() */
+static inline int check_parents_and_squalloc_upper_levels(flush_pos_t * pos,
+                                                         znode * left,
+                                                         znode * right)
+{
+       if (znode_same_parents(left, right))
+               return 0;
+
+       return squalloc_upper_levels(pos, left, right);
+}
+
+/* Check whether the parent of given @right node needs to be processes
+   ((re)allocated) prior to processing of the child.  If @left and @right do not
+   share at least the parent of the @right is after the @left but before the
+   @right in parent-first order, we have to (re)allocate it before the @right
+   gets (re)allocated. */
+static int squalloc_upper_levels(flush_pos_t * pos, znode * left, znode * right)
+{
+       int ret;
+
+       lock_handle left_parent_lock;
+       lock_handle right_parent_lock;
+
+       load_count left_parent_load;
+       load_count right_parent_load;
+
+       init_lh(&left_parent_lock);
+       init_lh(&right_parent_lock);
+
+       init_load_count(&left_parent_load);
+       init_load_count(&right_parent_load);
+
+       ret = reiser4_get_parent(&left_parent_lock, left, ZNODE_WRITE_LOCK);
+       if (ret)
+               goto out;
+
+       ret = reiser4_get_parent(&right_parent_lock, right, ZNODE_WRITE_LOCK);
+       if (ret)
+               goto out;
+
+       /* Check for same parents */
+       if (left_parent_lock.node == right_parent_lock.node)
+               goto out;
+
+       if (znode_check_flushprepped(right_parent_lock.node)) {
+               /* Keep parent-first order.  In the order, the right parent node stands
+                  before the @right node.  If it is already allocated, we set the
+                  preceder (next block search start point) to its block number, @right
+                  node should be allocated after it.
+
+                  However, preceder is set only if the right parent is on twig level.
+                  The explanation is the following: new branch nodes are allocated over
+                  already allocated children while the tree grows, it is difficult to
+                  keep tree ordered, we assume that only leaves and twings are correctly
+                  allocated.  So, only twigs are used as a preceder for allocating of the
+                  rest of the slum. */
+               if (znode_get_level(right_parent_lock.node) == TWIG_LEVEL) {
+                       pos->preceder.blk =
+                           *znode_get_block(right_parent_lock.node);
+                       check_preceder(pos->preceder.blk);
+               }
+               goto out;
+       }
+
+       ret = incr_load_count_znode(&left_parent_load, left_parent_lock.node);
+       if (ret)
+               goto out;
+
+       ret = incr_load_count_znode(&right_parent_load, right_parent_lock.node);
+       if (ret)
+               goto out;
+
+       ret =
+           squeeze_right_neighbor(pos, left_parent_lock.node,
+                                  right_parent_lock.node);
+       /* We stop if error. We stop if some items/units were shifted (ret == 0)
+        * and thus @right changed its parent. It means we have not process
+        * right_parent node prior to processing of @right. Positive return
+        * values say that shifting items was not happen because of "empty
+        * source" or "target full" conditions. */
+       if (ret <= 0)
+               goto out;
+
+       /* parent(@left) and parent(@right) may have different parents also. We
+        * do a recursive call for checking that. */
+       ret =
+           check_parents_and_squalloc_upper_levels(pos, left_parent_lock.node,
+                                                   right_parent_lock.node);
+       if (ret)
+               goto out;
+
+       /* allocate znode when going down */
+       ret = lock_parent_and_allocate_znode(right_parent_lock.node, pos);
+
+      out:
+       done_load_count(&left_parent_load);
+       done_load_count(&right_parent_load);
+
+       done_lh(&left_parent_lock);
+       done_lh(&right_parent_lock);
+
+       return ret;
+}
+
+/* Check the leftmost child "flushprepped" status, also returns true if child
+ * node was not found in cache.  */
+static int leftmost_child_of_unit_check_flushprepped(const coord_t * coord)
+{
+       int ret;
+       int prepped;
+
+       jnode *child;
+
+       ret = get_leftmost_child_of_unit(coord, &child);
+
+       if (ret)
+               return ret;
+
+       if (child) {
+               prepped = jnode_check_flushprepped(child);
+               jput(child);
+       } else {
+               /* We consider not existing child as a node which slum
+                  processing should not continue to.  Not cached node is clean,
+                  so it is flushprepped. */
+               prepped = 1;
+       }
+
+       return prepped;
+}
+
+/* (re)allocate znode with automated getting parent node */
+static int lock_parent_and_allocate_znode(znode * node, flush_pos_t * pos)
+{
+       int ret;
+       lock_handle parent_lock;
+       load_count parent_load;
+       coord_t pcoord;
+
+       assert("zam-851", znode_is_write_locked(node));
+
+       init_lh(&parent_lock);
+       init_load_count(&parent_load);
+
+       ret = reiser4_get_parent(&parent_lock, node, ZNODE_WRITE_LOCK);
+       if (ret)
+               goto out;
+
+       ret = incr_load_count_znode(&parent_load, parent_lock.node);
+       if (ret)
+               goto out;
+
+       ret = find_child_ptr(parent_lock.node, node, &pcoord);
+       if (ret)
+               goto out;
+
+       ret = allocate_znode(node, &pcoord, pos);
+
+      out:
+       done_load_count(&parent_load);
+       done_lh(&parent_lock);
+       return ret;
+}
+
+/* Process nodes on leaf level until unformatted node or rightmost node in the
+ * slum reached.  */
+static int handle_pos_on_formatted(flush_pos_t * pos)
+{
+       int ret;
+       lock_handle right_lock;
+       load_count right_load;
+
+       init_lh(&right_lock);
+       init_load_count(&right_load);
+
+       if (should_convert_node(pos, pos->lock.node)) {
+               ret = convert_node(pos, pos->lock.node);
+               if (ret)
+                       return ret;
+       }
+
+       while (1) {
+               ret =
+                   neighbor_in_slum(pos->lock.node, &right_lock, RIGHT_SIDE,
+                                    ZNODE_WRITE_LOCK,
+                                    !should_convert_next_node(pos,
+                                                              right_lock.
+                                                              node));
+               if (ret)
+                       break;
+
+               /* we don't prep(allocate) nodes for flushing twice.  This can be suboptimal, or it
+                * can be optimal.  For now we choose to live with the risk that it will
+                * be suboptimal because it would be quite complex to code it to be
+                * smarter. */
+               if (znode_check_flushprepped(right_lock.node)
+                   && !znode_convertible(right_lock.node)) {
+                       assert("edward-1005",
+                              !should_convert_next_node(pos, right_lock.node));
+                       pos_stop(pos);
+                       break;
+               }
+
+               ret = incr_load_count_znode(&right_load, right_lock.node);
+               if (ret)
+                       break;
+
+               if (should_convert_node(pos, right_lock.node)) {
+                       ret = convert_node(pos, right_lock.node);
+                       if (ret)
+                               break;
+                       if (node_is_empty(right_lock.node)) {
+                               /* node became empty after converting, repeat */
+                               done_load_count(&right_load);
+                               done_lh(&right_lock);
+                               continue;
+                       }
+               }
+
+               /* squeeze _before_ going upward. */
+               ret =
+                   squeeze_right_neighbor(pos, pos->lock.node,
+                                          right_lock.node);
+               if (ret < 0)
+                       break;
+
+               if (znode_check_flushprepped(right_lock.node)) {
+                       if (should_convert_next_node(pos, right_lock.node)) {
+                               /* in spite of flushprepped status of the node,
+                                  its right slum neighbor should be converted */
+                               assert("edward-953", convert_data(pos));
+                               assert("edward-954", item_convert_data(pos));
+
+                               if (node_is_empty(right_lock.node)) {
+                                       done_load_count(&right_load);
+                                       done_lh(&right_lock);
+                               } else
+                                       move_flush_pos(pos, &right_lock,
+                                                      &right_load, NULL);
+                               continue;
+                       }
+                       pos_stop(pos);
+                       break;
+               }
+
+               if (node_is_empty(right_lock.node)) {
+                       /* repeat if right node was squeezed completely */
+                       done_load_count(&right_load);
+                       done_lh(&right_lock);
+                       continue;
+               }
+
+               /* parent(right_lock.node) has to be processed before
+                * (right_lock.node) due to "parent-first" allocation order. */
+               ret =
+                   check_parents_and_squalloc_upper_levels(pos, pos->lock.node,
+                                                           right_lock.node);
+               if (ret)
+                       break;
+               /* (re)allocate _after_ going upward */
+               ret = lock_parent_and_allocate_znode(right_lock.node, pos);
+               if (ret)
+                       break;
+
+               if (should_terminate_squalloc(pos)) {
+                       set_item_convert_count(pos, 0);
+                       break;
+               }
+
+               /* advance the flush position to the right neighbor */
+               move_flush_pos(pos, &right_lock, &right_load, NULL);
+
+               ret = rapid_flush(pos);
+               if (ret)
+                       break;
+       }
+
+       assert("edward-1006", !convert_data(pos) || !item_convert_data(pos));
+
+       done_load_count(&right_load);
+       done_lh(&right_lock);
+
+       /* This function indicates via pos whether to stop or go to twig or continue on current
+        * level. */
+       return ret;
+
+}
+
+/* Process nodes on leaf level until unformatted node or rightmost node in the
+ * slum reached.  */
+static int handle_pos_on_leaf(flush_pos_t * pos)
+{
+       int ret;
+
+       assert("zam-845", pos->state == POS_ON_LEAF);
+
+       ret = handle_pos_on_formatted(pos);
+
+       if (ret == -E_NO_NEIGHBOR) {
+               /* cannot get right neighbor, go process extents. */
+               pos->state = POS_TO_TWIG;
+               return 0;
+       }
+
+       return ret;
+}
+
+/* Process slum on level > 1 */
+static int handle_pos_on_internal(flush_pos_t * pos)
+{
+       assert("zam-850", pos->state == POS_ON_INTERNAL);
+       return handle_pos_on_formatted(pos);
+}
+
+/* check whether squalloc should stop before processing given extent */
+static int squalloc_extent_should_stop(flush_pos_t * pos)
+{
+       assert("zam-869", item_is_extent(&pos->coord));
+
+       /* pos->child is a jnode handle_pos_on_extent() should start with in
+        * stead of the first child of the first extent unit. */
+       if (pos->child) {
+               int prepped;
+
+               assert("vs-1383", jnode_is_unformatted(pos->child));
+               prepped = jnode_check_flushprepped(pos->child);
+               pos->pos_in_unit =
+                   jnode_get_index(pos->child) -
+                   extent_unit_index(&pos->coord);
+               assert("vs-1470",
+                      pos->pos_in_unit < extent_unit_width(&pos->coord));
+               assert("nikita-3434",
+                      ergo(extent_is_unallocated(&pos->coord),
+                           pos->pos_in_unit == 0));
+               jput(pos->child);
+               pos->child = NULL;
+
+               return prepped;
+       }
+
+       pos->pos_in_unit = 0;
+       if (extent_is_unallocated(&pos->coord))
+               return 0;
+
+       return leftmost_child_of_unit_check_flushprepped(&pos->coord);
+}
+
+/* Handle the case when regular reiser4 tree (znodes connected one to its
+ * neighbors by sibling pointers) is interrupted on leaf level by one or more
+ * unformatted nodes.  By having a lock on twig level and use extent code
+ * routines to process unformatted nodes we swim around an irregular part of
+ * reiser4 tree. */
+static int handle_pos_on_twig(flush_pos_t * pos)
+{
+       int ret;
+
+       assert("zam-844", pos->state == POS_ON_EPOINT);
+       assert("zam-843", item_is_extent(&pos->coord));
+
+       /* We decide should we continue slum processing with current extent
+          unit: if leftmost child of current extent unit is flushprepped
+          (i.e. clean or already processed by flush) we stop squalloc().  There
+          is a fast check for unallocated extents which we assume contain all
+          not flushprepped nodes. */
+       /* FIXME: Here we implement simple check, we are only looking on the
+          leftmost child. */
+       ret = squalloc_extent_should_stop(pos);
+       if (ret != 0) {
+               pos_stop(pos);
+               return ret;
+       }
+
+       while (pos_valid(pos) && coord_is_existing_unit(&pos->coord)
+              && item_is_extent(&pos->coord)) {
+               ret = reiser4_alloc_extent(pos);
+               if (ret) {
+                       break;
+               }
+               coord_next_unit(&pos->coord);
+       }
+
+       if (coord_is_after_rightmost(&pos->coord)) {
+               pos->state = POS_END_OF_TWIG;
+               return 0;
+       }
+       if (item_is_internal(&pos->coord)) {
+               pos->state = POS_TO_LEAF;
+               return 0;
+       }
+
+       assert("zam-860", item_is_extent(&pos->coord));
+
+       /* "slum" is over */
+       pos->state = POS_INVALID;
+       return 0;
+}
+
+/* When we about to return flush position from twig to leaf level we can process
+ * the right twig node or move position to the leaf.  This processes right twig
+ * if it is possible and jump to leaf level if not. */
+static int handle_pos_end_of_twig(flush_pos_t * pos)
+{
+       int ret;
+       lock_handle right_lock;
+       load_count right_load;
+       coord_t at_right;
+       jnode *child = NULL;
+
+       assert("zam-848", pos->state == POS_END_OF_TWIG);
+       assert("zam-849", coord_is_after_rightmost(&pos->coord));
+
+       init_lh(&right_lock);
+       init_load_count(&right_load);
+
+       /* We get a lock on the right twig node even it is not dirty because
+        * slum continues or discontinues on leaf level not on next twig. This
+        * lock on the right twig is needed for getting its leftmost child. */
+       ret =
+           reiser4_get_right_neighbor(&right_lock, pos->lock.node,
+                                      ZNODE_WRITE_LOCK, GN_SAME_ATOM);
+       if (ret)
+               goto out;
+
+       ret = incr_load_count_znode(&right_load, right_lock.node);
+       if (ret)
+               goto out;
+
+       /* right twig could be not dirty */
+       if (JF_ISSET(ZJNODE(right_lock.node), JNODE_DIRTY)) {
+               /* If right twig node is dirty we always attempt to squeeze it
+                * content to the left... */
+             became_dirty:
+               ret =
+                   squeeze_right_twig_and_advance_coord(pos, right_lock.node);
+               if (ret <= 0) {
+                       /* pos->coord is on internal item, go to leaf level, or
+                        * we have an error which will be caught in squalloc() */
+                       pos->state = POS_TO_LEAF;
+                       goto out;
+               }
+
+               /* If right twig was squeezed completely we wave to re-lock
+                * right twig. now it is done through the top-level squalloc
+                * routine. */
+               if (node_is_empty(right_lock.node))
+                       goto out;
+
+               /* ... and prep it if it is not yet prepped */
+               if (!znode_check_flushprepped(right_lock.node)) {
+                       /* As usual, process parent before ... */
+                       ret =
+                           check_parents_and_squalloc_upper_levels(pos,
+                                                                   pos->lock.
+                                                                   node,
+                                                                   right_lock.
+                                                                   node);
+                       if (ret)
+                               goto out;
+
+                       /* ... processing the child */
+                       ret =
+                           lock_parent_and_allocate_znode(right_lock.node,
+                                                          pos);
+                       if (ret)
+                               goto out;
+               }
+       } else {
+               coord_init_first_unit(&at_right, right_lock.node);
+
+               /* check first child of next twig, should we continue there ? */
+               ret = get_leftmost_child_of_unit(&at_right, &child);
+               if (ret || child == NULL || jnode_check_flushprepped(child)) {
+                       pos_stop(pos);
+                       goto out;
+               }
+
+               /* check clean twig for possible relocation */
+               if (!znode_check_flushprepped(right_lock.node)) {
+                       ret =
+                           reverse_relocate_check_dirty_parent(child,
+                                                               &at_right, pos);
+                       if (ret)
+                               goto out;
+                       if (JF_ISSET(ZJNODE(right_lock.node), JNODE_DIRTY))
+                               goto became_dirty;
+               }
+       }
+
+       assert("zam-875", znode_check_flushprepped(right_lock.node));
+
+       /* Update the preceder by a block number of just processed right twig
+        * node. The code above could miss the preceder updating because
+        * allocate_znode() could not be called for this node. */
+       pos->preceder.blk = *znode_get_block(right_lock.node);
+       check_preceder(pos->preceder.blk);
+
+       coord_init_first_unit(&at_right, right_lock.node);
+       assert("zam-868", coord_is_existing_unit(&at_right));
+
+       pos->state = item_is_extent(&at_right) ? POS_ON_EPOINT : POS_TO_LEAF;
+       move_flush_pos(pos, &right_lock, &right_load, &at_right);
+
+      out:
+       done_load_count(&right_load);
+       done_lh(&right_lock);
+
+       if (child)
+               jput(child);
+
+       return ret;
+}
+
+/* Move the pos->lock to leaf node pointed by pos->coord, check should we
+ * continue there. */
+static int handle_pos_to_leaf(flush_pos_t * pos)
+{
+       int ret;
+       lock_handle child_lock;
+       load_count child_load;
+       jnode *child;
+
+       assert("zam-846", pos->state == POS_TO_LEAF);
+       assert("zam-847", item_is_internal(&pos->coord));
+
+       init_lh(&child_lock);
+       init_load_count(&child_load);
+
+       ret = get_leftmost_child_of_unit(&pos->coord, &child);
+       if (ret)
+               return ret;
+       if (child == NULL) {
+               pos_stop(pos);
+               return 0;
+       }
+
+       if (jnode_check_flushprepped(child)) {
+               pos->state = POS_INVALID;
+               goto out;
+       }
+
+       ret =
+           longterm_lock_znode(&child_lock, JZNODE(child), ZNODE_WRITE_LOCK,
+                               ZNODE_LOCK_LOPRI);
+       if (ret)
+               goto out;
+
+       ret = incr_load_count_znode(&child_load, JZNODE(child));
+       if (ret)
+               goto out;
+
+       ret = allocate_znode(JZNODE(child), &pos->coord, pos);
+       if (ret)
+               goto out;
+
+       /* move flush position to leaf level */
+       pos->state = POS_ON_LEAF;
+       move_flush_pos(pos, &child_lock, &child_load, NULL);
+
+       if (node_is_empty(JZNODE(child))) {
+               ret = delete_empty_node(JZNODE(child));
+               pos->state = POS_INVALID;
+       }
+      out:
+       done_load_count(&child_load);
+       done_lh(&child_lock);
+       jput(child);
+
+       return ret;
+}
+
+/* move pos from leaf to twig, and move lock from leaf to twig. */
+/* Move pos->lock to upper (twig) level */
+static int handle_pos_to_twig(flush_pos_t * pos)
+{
+       int ret;
+
+       lock_handle parent_lock;
+       load_count parent_load;
+       coord_t pcoord;
+
+       assert("zam-852", pos->state == POS_TO_TWIG);
+
+       init_lh(&parent_lock);
+       init_load_count(&parent_load);
+
+       ret =
+           reiser4_get_parent(&parent_lock, pos->lock.node, ZNODE_WRITE_LOCK);
+       if (ret)
+               goto out;
+
+       ret = incr_load_count_znode(&parent_load, parent_lock.node);
+       if (ret)
+               goto out;
+
+       ret = find_child_ptr(parent_lock.node, pos->lock.node, &pcoord);
+       if (ret)
+               goto out;
+
+       assert("zam-870", item_is_internal(&pcoord));
+       coord_next_item(&pcoord);
+
+       if (coord_is_after_rightmost(&pcoord))
+               pos->state = POS_END_OF_TWIG;
+       else if (item_is_extent(&pcoord))
+               pos->state = POS_ON_EPOINT;
+       else {
+               /* Here we understand that getting -E_NO_NEIGHBOR in
+                * handle_pos_on_leaf() was because of just a reaching edge of
+                * slum */
+               pos_stop(pos);
+               goto out;
+       }
+
+       move_flush_pos(pos, &parent_lock, &parent_load, &pcoord);
+
+      out:
+       done_load_count(&parent_load);
+       done_lh(&parent_lock);
+
+       return ret;
+}
+
+typedef int (*pos_state_handle_t) (flush_pos_t *);
+static pos_state_handle_t flush_pos_handlers[] = {
+       /* process formatted nodes on leaf level, keep lock on a leaf node */
+       [POS_ON_LEAF] = handle_pos_on_leaf,
+       /* process unformatted nodes, keep lock on twig node, pos->coord points to extent currently
+        * being processed */
+       [POS_ON_EPOINT] = handle_pos_on_twig,
+       /* move a lock from leaf node to its parent for further processing of unformatted nodes */
+       [POS_TO_TWIG] = handle_pos_to_twig,
+       /* move a lock from twig to leaf level when a processing of unformatted nodes finishes,
+        * pos->coord points to the leaf node we jump to */
+       [POS_TO_LEAF] = handle_pos_to_leaf,
+       /* after processing last extent in the twig node, attempting to shift items from the twigs
+        * right neighbor and process them while shifting */
+       [POS_END_OF_TWIG] = handle_pos_end_of_twig,
+       /* process formatted nodes on internal level, keep lock on an internal node */
+       [POS_ON_INTERNAL] = handle_pos_on_internal
+};
+
+/* Advance flush position horizontally, prepare for flushing ((re)allocate, squeeze,
+ * encrypt) nodes and their ancestors in "parent-first" order */
+static int squalloc(flush_pos_t * pos)
+{
+       int ret = 0;
+
+       /* maybe needs to be made a case statement with handle_pos_on_leaf as first case, for
+        * greater CPU efficiency? Measure and see.... -Hans */
+       while (pos_valid(pos)) {
+               ret = flush_pos_handlers[pos->state] (pos);
+               if (ret < 0)
+                       break;
+
+               ret = rapid_flush(pos);
+               if (ret)
+                       break;
+       }
+
+       /* any positive value or -E_NO_NEIGHBOR are legal return codes for handle_pos*
+          routines, -E_NO_NEIGHBOR means that slum edge was reached */
+       if (ret > 0 || ret == -E_NO_NEIGHBOR)
+               ret = 0;
+
+       return ret;
+}
+
+static void update_ldkey(znode * node)
+{
+       reiser4_key ldkey;
+
+       assert_rw_write_locked(&(znode_get_tree(node)->dk_lock));
+       if (node_is_empty(node))
+               return;
+
+       znode_set_ld_key(node, leftmost_key_in_node(node, &ldkey));
+}
+
+/* this is to be called after calling of shift node's method to shift data from @right to
+   @left. It sets left delimiting keys of @left and @right to keys of first items of @left
+   and @right correspondingly and sets right delimiting key of @left to first key of @right */
+static void update_znode_dkeys(znode * left, znode * right)
+{
+       assert_rw_write_locked(&(znode_get_tree(right)->dk_lock));
+       assert("vs-1629", (znode_is_write_locked(left) &&
+                          znode_is_write_locked(right)));
+
+       /* we need to update left delimiting of left if it was empty before shift */
+       update_ldkey(left);
+       update_ldkey(right);
+       if (node_is_empty(right))
+               znode_set_rd_key(left, znode_get_rd_key(right));
+       else
+               znode_set_rd_key(left, znode_get_ld_key(right));
+}
+
+/* try to shift everything from @right to @left. If everything was shifted -
+   @right is removed from the tree.  Result is the number of bytes shifted. */
+static int
+shift_everything_left(znode * right, znode * left, carry_level * todo)
+{
+       coord_t from;
+       node_plugin *nplug;
+       carry_plugin_info info;
+
+       coord_init_after_last_item(&from, right);
+
+       nplug = node_plugin_by_node(right);
+       info.doing = NULL;
+       info.todo = todo;
+       return nplug->shift(&from, left, SHIFT_LEFT,
+                           1 /* delete @right if it becomes empty */ ,
+                           1
+                           /* move coord @from to node @left if everything will be shifted */
+                           ,
+                           &info);
+}
+
+/* Shift as much as possible from @right to @left using the memcpy-optimized
+   shift_everything_left.  @left and @right are formatted neighboring nodes on
+   leaf level. */
+static int squeeze_right_non_twig(znode * left, znode * right)
+{
+       int ret;
+       carry_pool *pool;
+       carry_level *todo;
+
+       assert("nikita-2246", znode_get_level(left) == znode_get_level(right));
+
+       if (!JF_ISSET(ZJNODE(left), JNODE_DIRTY) ||
+           !JF_ISSET(ZJNODE(right), JNODE_DIRTY))
+               return SQUEEZE_TARGET_FULL;
+
+       pool = init_carry_pool(sizeof(*pool) + 3 * sizeof(*todo));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       todo = (carry_level *) (pool + 1);
+       init_carry_level(todo, pool);
+
+       ret = shift_everything_left(right, left, todo);
+       if (ret > 0) {
+               /* something was shifted */
+               reiser4_tree *tree;
+               __u64 grabbed;
+
+               znode_make_dirty(left);
+               znode_make_dirty(right);
+
+               /* update delimiting keys of nodes which participated in
+                  shift. FIXME: it would be better to have this in shift
+                  node's operation. But it can not be done there. Nobody
+                  remembers why, though */
+               tree = znode_get_tree(left);
+               write_lock_dk(tree);
+               update_znode_dkeys(left, right);
+               write_unlock_dk(tree);
+
+               /* Carry is called to update delimiting key and, maybe, to remove empty
+                  node. */
+               grabbed = get_current_context()->grabbed_blocks;
+               ret = reiser4_grab_space_force(tree->height, BA_RESERVED);
+               assert("nikita-3003", ret == 0);        /* reserved space is exhausted. Ask Hans. */
+               ret = reiser4_carry(todo, NULL /* previous level */ );
+               grabbed2free_mark(grabbed);
+       } else {
+               /* Shifting impossible, we return appropriate result code */
+               ret =
+                   node_is_empty(right) ? SQUEEZE_SOURCE_EMPTY :
+                   SQUEEZE_TARGET_FULL;
+       }
+
+       done_carry_pool(pool);
+
+       return ret;
+}
+
+#if REISER4_DEBUG
+static int sibling_link_is_ok(const znode *left, const znode *right)
+{
+       int result;
+
+       read_lock_tree(znode_get_tree(left));
+       result = (left->right == right && left == right->left);
+       read_unlock_tree(znode_get_tree(left));
+       return result;
+}
+#endif
+
+/* Shift first unit of first item if it is an internal one.  Return
+   SQUEEZE_TARGET_FULL if it fails to shift an item, otherwise return
+   SUBTREE_MOVED. */
+static int shift_one_internal_unit(znode * left, znode * right)
+{
+       int ret;
+       carry_pool *pool;
+       carry_level *todo;
+       coord_t *coord;
+       carry_plugin_info *info;
+       int size, moved;
+
+       assert("nikita-2247", znode_get_level(left) == znode_get_level(right));
+       assert("nikita-2435", znode_is_write_locked(left));
+       assert("nikita-2436", znode_is_write_locked(right));
+       assert("nikita-2434", sibling_link_is_ok(left, right));
+
+       pool = init_carry_pool(sizeof(*pool) + 3 * sizeof(*todo) +
+                              sizeof(*coord) + sizeof(*info)
+#if REISER4_DEBUG
+                              + sizeof(*coord) + 2 * sizeof(reiser4_key)
+#endif
+           );
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       todo = (carry_level *) (pool + 1);
+       init_carry_level(todo, pool);
+
+       coord = (coord_t *) (todo + 3);
+       coord_init_first_unit(coord, right);
+       info = (carry_plugin_info *) (coord + 1);
+
+#if REISER4_DEBUG
+       if (!node_is_empty(left)) {
+               coord_t *last;
+               reiser4_key *right_key;
+               reiser4_key *left_key;
+
+               last = (coord_t *) (info + 1);
+               right_key = (reiser4_key *) (last + 1);
+               left_key = right_key + 1;
+               coord_init_last_unit(last, left);
+
+               assert("nikita-2463",
+                      keyle(item_key_by_coord(last, left_key),
+                            item_key_by_coord(coord, right_key)));
+       }
+#endif
+
+       assert("jmacd-2007", item_is_internal(coord));
+
+       size = item_length_by_coord(coord);
+       info->todo = todo;
+       info->doing = NULL;
+
+       ret = node_plugin_by_node(left)->shift(coord, left, SHIFT_LEFT,
+                                              1
+                                              /* delete @right if it becomes empty */
+                                              ,
+                                              0
+                                              /* do not move coord @coord to node @left */
+                                              ,
+                                              info);
+
+       /* If shift returns positive, then we shifted the item. */
+       assert("vs-423", ret <= 0 || size == ret);
+       moved = (ret > 0);
+
+       if (moved) {
+               /* something was moved */
+               reiser4_tree *tree;
+               int grabbed;
+
+               znode_make_dirty(left);
+               znode_make_dirty(right);
+               tree = znode_get_tree(left);
+               write_lock_dk(tree);
+               update_znode_dkeys(left, right);
+               write_unlock_dk(tree);
+
+               /* reserve space for delimiting keys after shifting */
+               grabbed = get_current_context()->grabbed_blocks;
+               ret = reiser4_grab_space_force(tree->height, BA_RESERVED);
+               assert("nikita-3003", ret == 0);        /* reserved space is exhausted. Ask Hans. */
+
+               ret = reiser4_carry(todo, NULL /* previous level */ );
+               grabbed2free_mark(grabbed);
+       }
+
+       done_carry_pool(pool);
+
+       if (ret != 0) {
+               /* Shift or carry operation failed. */
+               assert("jmacd-7325", ret < 0);
+               return ret;
+       }
+
+       return moved ? SUBTREE_MOVED : SQUEEZE_TARGET_FULL;
+}
+
+/* Make the final relocate/wander decision during forward parent-first squalloc for a
+   znode.  For unformatted nodes this is done in plugin/item/extent.c:extent_needs_allocation(). */
+static int
+allocate_znode_loaded(znode * node,
+                     const coord_t * parent_coord, flush_pos_t * pos)
+{
+       int ret;
+       reiser4_super_info_data *sbinfo = get_current_super_private();
+       /* FIXME(D): We have the node write-locked and should have checked for !
+          allocated() somewhere before reaching this point, but there can be a race, so
+          this assertion is bogus. */
+       assert("jmacd-7987", !jnode_check_flushprepped(ZJNODE(node)));
+       assert("jmacd-7988", znode_is_write_locked(node));
+       assert("jmacd-7989", coord_is_invalid(parent_coord)
+              || znode_is_write_locked(parent_coord->node));
+
+       if (ZF_ISSET(node, JNODE_REPACK) || ZF_ISSET(node, JNODE_CREATED) ||
+           znode_is_root(node) ||
+           /* We have enough nodes to relocate no matter what. */
+           (pos->leaf_relocate != 0 && znode_get_level(node) == LEAF_LEVEL)) {
+               /* No need to decide with new nodes, they are treated the same as
+                  relocate. If the root node is dirty, relocate. */
+               if (pos->preceder.blk == 0) {
+                       /* preceder is unknown and we have decided to relocate node --
+                          using of default value for search start is better than search
+                          from block #0. */
+                       get_blocknr_hint_default(&pos->preceder.blk);
+                       check_preceder(pos->preceder.blk);
+               }
+
+               goto best_reloc;
+
+       } else if (pos->preceder.blk == 0) {
+               /* If we don't know the preceder, leave it where it is. */
+               jnode_make_wander(ZJNODE(node));
+       } else {
+               /* Make a decision based on block distance. */
+               reiser4_block_nr dist;
+               reiser4_block_nr nblk = *znode_get_block(node);
+
+               assert("jmacd-6172", !reiser4_blocknr_is_fake(&nblk));
+               assert("jmacd-6173", !reiser4_blocknr_is_fake(&pos->preceder.blk));
+               assert("jmacd-6174", pos->preceder.blk != 0);
+
+               if (pos->preceder.blk == nblk - 1) {
+                       /* Ideal. */
+                       jnode_make_wander(ZJNODE(node));
+               } else {
+
+                       dist =
+                           (nblk <
+                            pos->preceder.blk) ? (pos->preceder.blk -
+                                                  nblk) : (nblk -
+                                                           pos->preceder.blk);
+
+                       /* See if we can find a closer block (forward direction only). */
+                       pos->preceder.max_dist =
+                           min((reiser4_block_nr) sbinfo->flush.
+                               relocate_distance, dist);
+                       pos->preceder.level = znode_get_level(node);
+
+                       ret = allocate_znode_update(node, parent_coord, pos);
+
+                       pos->preceder.max_dist = 0;
+
+                       if (ret && (ret != -ENOSPC))
+                               return ret;
+
+                       if (ret == 0) {
+                               /* Got a better allocation. */
+                               znode_make_reloc(node, pos->fq);
+                       } else if (dist < sbinfo->flush.relocate_distance) {
+                               /* The present allocation is good enough. */
+                               jnode_make_wander(ZJNODE(node));
+                       } else {
+                               /* Otherwise, try to relocate to the best position. */
+                             best_reloc:
+                               ret =
+                                   allocate_znode_update(node, parent_coord,
+                                                         pos);
+                               if (ret != 0)
+                                       return ret;
+
+                               /* set JNODE_RELOC bit _after_ node gets allocated */
+                               znode_make_reloc(node, pos->fq);
+                       }
+               }
+       }
+
+       /* This is the new preceder. */
+       pos->preceder.blk = *znode_get_block(node);
+       check_preceder(pos->preceder.blk);
+       pos->alloc_cnt += 1;
+
+       assert("jmacd-4277", !reiser4_blocknr_is_fake(&pos->preceder.blk));
+
+       return 0;
+}
+
+static int
+allocate_znode(znode * node, const coord_t * parent_coord, flush_pos_t * pos)
+{
+       /*
+        * perform znode allocation with znode pinned in memory to avoid races
+        * with asynchronous emergency flush (which plays with
+        * JNODE_FLUSH_RESERVED bit).
+        */
+       return WITH_DATA(node, allocate_znode_loaded(node, parent_coord, pos));
+}
+
+/* A subroutine of allocate_znode, this is called first to see if there is a close
+   position to relocate to.  It may return ENOSPC if there is no close position.  If there
+   is no close position it may not relocate.  This takes care of updating the parent node
+   with the relocated block address. */
+static int
+allocate_znode_update(znode * node, const coord_t * parent_coord,
+                     flush_pos_t * pos)
+{
+       int ret;
+       reiser4_block_nr blk;
+       lock_handle uber_lock;
+       int flush_reserved_used = 0;
+       int grabbed;
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       init_lh(&uber_lock);
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       grabbed = ctx->grabbed_blocks;
+
+       /* discard e-flush allocation */
+       ret = zload(node);
+       if (ret)
+               return ret;
+
+       if (ZF_ISSET(node, JNODE_CREATED)) {
+               assert("zam-816", reiser4_blocknr_is_fake(znode_get_block(node)));
+               pos->preceder.block_stage = BLOCK_UNALLOCATED;
+       } else {
+               pos->preceder.block_stage = BLOCK_GRABBED;
+
+               /* The disk space for relocating the @node is already reserved in "flush reserved"
+                * counter if @node is leaf, otherwise we grab space using BA_RESERVED (means grab
+                * space from whole disk not from only 95%). */
+               if (znode_get_level(node) == LEAF_LEVEL) {
+                       /*
+                        * earlier (during do_jnode_make_dirty()) we decided
+                        * that @node can possibly go into overwrite set and
+                        * reserved block for its wandering location.
+                        */
+                       txn_atom *atom = get_current_atom_locked();
+                       assert("nikita-3449",
+                              ZF_ISSET(node, JNODE_FLUSH_RESERVED));
+                       flush_reserved2grabbed(atom, (__u64) 1);
+                       spin_unlock_atom(atom);
+                       /*
+                        * we are trying to move node into relocate
+                        * set. Allocation of relocated position "uses"
+                        * reserved block.
+                        */
+                       ZF_CLR(node, JNODE_FLUSH_RESERVED);
+                       flush_reserved_used = 1;
+               } else {
+                       ret = reiser4_grab_space_force((__u64) 1, BA_RESERVED);
+                       if (ret != 0)
+                               goto exit;
+               }
+       }
+
+       /* We may do not use 5% of reserved disk space here and flush will not pack tightly. */
+       ret = reiser4_alloc_block(&pos->preceder, &blk,
+                                 BA_FORMATTED | BA_PERMANENT);
+       if (ret)
+               goto exit;
+
+       if (!ZF_ISSET(node, JNODE_CREATED) &&
+           (ret =
+            reiser4_dealloc_block(znode_get_block(node), 0,
+                                  BA_DEFER | BA_FORMATTED)))
+               goto exit;
+
+       if (likely(!znode_is_root(node))) {
+               item_plugin *iplug;
+
+               iplug = item_plugin_by_coord(parent_coord);
+               assert("nikita-2954", iplug->f.update != NULL);
+               iplug->f.update(parent_coord, &blk);
+
+               znode_make_dirty(parent_coord->node);
+
+       } else {
+               reiser4_tree *tree = znode_get_tree(node);
+               znode *uber;
+
+               /* We take a longterm lock on the fake node in order to change
+                  the root block number.  This may cause atom fusion. */
+               ret = get_uber_znode(tree, ZNODE_WRITE_LOCK, ZNODE_LOCK_HIPRI,
+                                    &uber_lock);
+               /* The fake node cannot be deleted, and we must have priority
+                  here, and may not be confused with ENOSPC. */
+               assert("jmacd-74412",
+                      ret != -EINVAL && ret != -E_DEADLOCK && ret != -ENOSPC);
+
+               if (ret)
+                       goto exit;
+
+               uber = uber_lock.node;
+
+               write_lock_tree(tree);
+               tree->root_block = blk;
+               write_unlock_tree(tree);
+
+               znode_make_dirty(uber);
+       }
+
+       ret = znode_rehash(node, &blk);
+      exit:
+       if (ret) {
+               /* Get flush reserved block back if something fails, because
+                * callers assume that on error block wasn't relocated and its
+                * flush reserved block wasn't used. */
+               if (flush_reserved_used) {
+                       /*
+                        * ok, we failed to move node into relocate
+                        * set. Restore status quo.
+                        */
+                       grabbed2flush_reserved((__u64) 1);
+                       ZF_SET(node, JNODE_FLUSH_RESERVED);
+               }
+       }
+       zrelse(node);
+       done_lh(&uber_lock);
+       grabbed2free_mark(grabbed);
+       return ret;
+}
+
+/* JNODE INTERFACE */
+
+/* Lock a node (if formatted) and then get its parent locked, set the child's
+   coordinate in the parent.  If the child is the root node, the above_root
+   znode is returned but the coord is not set.  This function may cause atom
+   fusion, but it is only used for read locks (at this point) and therefore
+   fusion only occurs when the parent is already dirty. */
+/* Hans adds this note: remember to ask how expensive this operation is vs. storing parent
+   pointer in jnodes. */
+static int
+jnode_lock_parent_coord(jnode * node,
+                       coord_t * coord,
+                       lock_handle * parent_lh,
+                       load_count * parent_zh,
+                       znode_lock_mode parent_mode, int try)
+{
+       int ret;
+
+       assert("edward-53", jnode_is_unformatted(node) || jnode_is_znode(node));
+       assert("edward-54", jnode_is_unformatted(node)
+              || znode_is_any_locked(JZNODE(node)));
+
+       if (!jnode_is_znode(node)) {
+               reiser4_key key;
+               tree_level stop_level = TWIG_LEVEL;
+               lookup_bias bias = FIND_EXACT;
+
+               assert("edward-168", !(jnode_get_type(node) == JNODE_BITMAP));
+
+               /* The case when node is not znode, but can have parent coord
+                  (unformatted node, node which represents cluster page,
+                  etc..).  Generate a key for the appropriate entry, search
+                  in the tree using coord_by_key, which handles locking for
+                  us. */
+
+               /*
+                * nothing is locked at this moment, so, nothing prevents
+                * concurrent truncate from removing jnode from inode. To
+                * prevent this spin-lock jnode. jnode can be truncated just
+                * after call to the jnode_build_key(), but this is ok,
+                * because coord_by_key() will just fail to find appropriate
+                * extent.
+                */
+               spin_lock_jnode(node);
+               if (!JF_ISSET(node, JNODE_HEARD_BANSHEE)) {
+                       jnode_build_key(node, &key);
+                       ret = 0;
+               } else
+                       ret = RETERR(-ENOENT);
+               spin_unlock_jnode(node);
+
+               if (ret != 0)
+                       return ret;
+
+               if (jnode_is_cluster_page(node))
+                       stop_level = LEAF_LEVEL;
+
+               assert("jmacd-1812", coord != NULL);
+
+               ret = coord_by_key(jnode_get_tree(node), &key, coord, parent_lh,
+                                  parent_mode, bias, stop_level, stop_level,
+                                  CBK_UNIQUE, NULL /*ra_info */ );
+               switch (ret) {
+               case CBK_COORD_NOTFOUND:
+                       assert("edward-1038",
+                              ergo(jnode_is_cluster_page(node),
+                                   JF_ISSET(node, JNODE_HEARD_BANSHEE)));
+                       if (!JF_ISSET(node, JNODE_HEARD_BANSHEE))
+                               warning("nikita-3177", "Parent not found");
+                       return ret;
+               case CBK_COORD_FOUND:
+                       if (coord->between != AT_UNIT) {
+                               /* FIXME: comment needed */
+                               done_lh(parent_lh);
+                               if (!JF_ISSET(node, JNODE_HEARD_BANSHEE)) {
+                                       warning("nikita-3178",
+                                               "Found but not happy: %i",
+                                               coord->between);
+                               }
+                               return RETERR(-ENOENT);
+                       }
+                       ret = incr_load_count_znode(parent_zh, parent_lh->node);
+                       if (ret != 0)
+                               return ret;
+                       /* if (jnode_is_cluster_page(node)) {
+                          races with write() are possible
+                          check_child_cluster (parent_lh->node);
+                          }
+                        */
+                       break;
+               default:
+                       return ret;
+               }
+
+       } else {
+               int flags;
+               znode *z;
+
+               z = JZNODE(node);
+               /* Formatted node case: */
+               assert("jmacd-2061", !znode_is_root(z));
+
+               flags = GN_ALLOW_NOT_CONNECTED;
+               if (try)
+                       flags |= GN_TRY_LOCK;
+
+               ret =
+                   reiser4_get_parent_flags(parent_lh, z, parent_mode, flags);
+               if (ret != 0)
+                       /* -E_REPEAT is ok here, it is handled by the caller. */
+                       return ret;
+
+               /* Make the child's position "hint" up-to-date.  (Unless above
+                  root, which caller must check.) */
+               if (coord != NULL) {
+
+                       ret = incr_load_count_znode(parent_zh, parent_lh->node);
+                       if (ret != 0) {
+                               warning("jmacd-976812386",
+                                       "incr_load_count_znode failed: %d",
+                                       ret);
+                               return ret;
+                       }
+
+                       ret = find_child_ptr(parent_lh->node, z, coord);
+                       if (ret != 0) {
+                               warning("jmacd-976812",
+                                       "find_child_ptr failed: %d", ret);
+                               return ret;
+                       }
+               }
+       }
+
+       return 0;
+}
+
+/* Get the (locked) next neighbor of a znode which is dirty and a member of the same atom.
+   If there is no next neighbor or the neighbor is not in memory or if there is a
+   neighbor but it is not dirty or not in the same atom, -E_NO_NEIGHBOR is returned.
+   In some cases the slum may include nodes which are not dirty, if so @check_dirty should be 0 */
+static int neighbor_in_slum(znode * node,      /* starting point */
+                           lock_handle * lock, /* lock on starting point */
+                           sideof side,        /* left or right direction we seek the next node in */
+                           znode_lock_mode mode,       /* kind of lock we want */
+                           int check_dirty)
+{                              /* true if the neighbor should be dirty */
+       int ret;
+
+       assert("jmacd-6334", znode_is_connected(node));
+
+       ret =
+           reiser4_get_neighbor(lock, node, mode,
+                                GN_SAME_ATOM | (side ==
+                                                LEFT_SIDE ? GN_GO_LEFT : 0));
+
+       if (ret) {
+               /* May return -ENOENT or -E_NO_NEIGHBOR. */
+               /* FIXME(C): check EINVAL, E_DEADLOCK */
+               if (ret == -ENOENT) {
+                       ret = RETERR(-E_NO_NEIGHBOR);
+               }
+
+               return ret;
+       }
+       if (!check_dirty)
+               return 0;
+       /* Check dirty bit of locked znode, no races here */
+       if (JF_ISSET(ZJNODE(lock->node), JNODE_DIRTY))
+               return 0;
+
+       done_lh(lock);
+       return RETERR(-E_NO_NEIGHBOR);
+}
+
+/* Return true if two znodes have the same parent.  This is called with both nodes
+   write-locked (for squeezing) so no tree lock is needed. */
+static int znode_same_parents(znode * a, znode * b)
+{
+       int result;
+
+       assert("jmacd-7011", znode_is_write_locked(a));
+       assert("jmacd-7012", znode_is_write_locked(b));
+
+       /* We lock the whole tree for this check.... I really don't like whole tree
+        * locks... -Hans */
+       read_lock_tree(znode_get_tree(a));
+       result = (znode_parent(a) == znode_parent(b));
+       read_unlock_tree(znode_get_tree(a));
+       return result;
+}
+
+/* FLUSH SCAN */
+
+/* Initialize the flush_scan data structure. */
+static void scan_init(flush_scan * scan)
+{
+       memset(scan, 0, sizeof(*scan));
+       init_lh(&scan->node_lock);
+       init_lh(&scan->parent_lock);
+       init_load_count(&scan->parent_load);
+       init_load_count(&scan->node_load);
+       coord_init_invalid(&scan->parent_coord, NULL);
+}
+
+/* Release any resources held by the flush scan, e.g., release locks, free memory, etc. */
+static void scan_done(flush_scan * scan)
+{
+       done_load_count(&scan->node_load);
+       if (scan->node != NULL) {
+               jput(scan->node);
+               scan->node = NULL;
+       }
+       done_load_count(&scan->parent_load);
+       done_lh(&scan->parent_lock);
+       done_lh(&scan->node_lock);
+}
+
+/* Returns true if flush scanning is finished. */
+int reiser4_scan_finished(flush_scan * scan)
+{
+       return scan->stop || (scan->direction == RIGHT_SIDE &&
+                             scan->count >= scan->max_count);
+}
+
+/* Return true if the scan should continue to the @tonode.  True if the node meets the
+   same_slum_check condition.  If not, deref the "left" node and stop the scan. */
+int reiser4_scan_goto(flush_scan * scan, jnode * tonode)
+{
+       int go = same_slum_check(scan->node, tonode, 1, 0);
+
+       if (!go) {
+               scan->stop = 1;
+               jput(tonode);
+       }
+
+       return go;
+}
+
+/* Set the current scan->node, refcount it, increment count by the @add_count (number to
+   count, e.g., skipped unallocated nodes), deref previous current, and copy the current
+   parent coordinate. */
+int
+scan_set_current(flush_scan * scan, jnode * node, unsigned add_count,
+                const coord_t * parent)
+{
+       /* Release the old references, take the new reference. */
+       done_load_count(&scan->node_load);
+
+       if (scan->node != NULL) {
+               jput(scan->node);
+       }
+       scan->node = node;
+       scan->count += add_count;
+
+       /* This next stmt is somewhat inefficient.  The reiser4_scan_extent() code could
+          delay this update step until it finishes and update the parent_coord only once.
+          It did that before, but there was a bug and this was the easiest way to make it
+          correct. */
+       if (parent != NULL) {
+               coord_dup(&scan->parent_coord, parent);
+       }
+
+       /* Failure may happen at the incr_load_count call, but the caller can assume the reference
+          is safely taken. */
+       return incr_load_count_jnode(&scan->node_load, node);
+}
+
+/* Return true if scanning in the leftward direction. */
+int reiser4_scanning_left(flush_scan * scan)
+{
+       return scan->direction == LEFT_SIDE;
+}
+
+/* Performs leftward scanning starting from either kind of node.  Counts the starting
+   node.  The right-scan object is passed in for the left-scan in order to copy the parent
+   of an unformatted starting position.  This way we avoid searching for the unformatted
+   node's parent when scanning in each direction.  If we search for the parent once it is
+   set in both scan objects.  The limit parameter tells flush-scan when to stop.
+
+   Rapid scanning is used only during scan_left, where we are interested in finding the
+   'leftpoint' where we begin flushing.  We are interested in stopping at the left child
+   of a twig that does not have a dirty left neighbor.  THIS IS A SPECIAL CASE.  The
+   problem is finding a way to flush only those nodes without unallocated children, and it
+   is difficult to solve in the bottom-up flushing algorithm we are currently using.  The
+   problem can be solved by scanning left at every level as we go upward, but this would
+   basically bring us back to using a top-down allocation strategy, which we already tried
+   (see BK history from May 2002), and has a different set of problems.  The top-down
+   strategy makes avoiding unallocated children easier, but makes it difficult to
+   propertly flush dirty children with clean parents that would otherwise stop the
+   top-down flush, only later to dirty the parent once the children are flushed.  So we
+   solve the problem in the bottom-up algorithm with a special case for twigs and leaves
+   only.
+
+   The first step in solving the problem is this rapid leftward scan.  After we determine
+   that there are at least enough nodes counted to qualify for FLUSH_RELOCATE_THRESHOLD we
+   are no longer interested in the exact count, we are only interested in finding a the
+   best place to start the flush.  We could choose one of two possibilities:
+
+   1. Stop at the leftmost child (of a twig) that does not have a dirty left neighbor.
+   This requires checking one leaf per rapid-scan twig
+
+   2. Stop at the leftmost child (of a twig) where there are no dirty children of the twig
+   to the left.  This requires checking possibly all of the in-memory children of each
+   twig during the rapid scan.
+
+   For now we implement the first policy.
+*/
+static int
+scan_left(flush_scan * scan, flush_scan * right, jnode * node, unsigned limit)
+{
+       int ret = 0;
+
+       scan->max_count = limit;
+       scan->direction = LEFT_SIDE;
+
+       ret = scan_set_current(scan, jref(node), 1, NULL);
+       if (ret != 0) {
+               return ret;
+       }
+
+       ret = scan_common(scan, right);
+       if (ret != 0) {
+               return ret;
+       }
+
+       /* Before rapid scanning, we need a lock on scan->node so that we can get its
+          parent, only if formatted. */
+       if (jnode_is_znode(scan->node)) {
+               ret = longterm_lock_znode(&scan->node_lock, JZNODE(scan->node),
+                                         ZNODE_WRITE_LOCK, ZNODE_LOCK_LOPRI);
+       }
+
+       /* Rapid_scan would go here (with limit set to FLUSH_RELOCATE_THRESHOLD). */
+       return ret;
+}
+
+/* Performs rightward scanning... Does not count the starting node.  The limit parameter
+   is described in scan_left.  If the starting node is unformatted then the
+   parent_coord was already set during scan_left.  The rapid_after parameter is not used
+   during right-scanning.
+
+   scan_right is only called if the scan_left operation does not count at least
+   FLUSH_RELOCATE_THRESHOLD nodes for flushing.  Otherwise, the limit parameter is set to
+   the difference between scan-left's count and FLUSH_RELOCATE_THRESHOLD, meaning
+   scan-right counts as high as FLUSH_RELOCATE_THRESHOLD and then stops. */
+static int scan_right(flush_scan * scan, jnode * node, unsigned limit)
+{
+       int ret;
+
+       scan->max_count = limit;
+       scan->direction = RIGHT_SIDE;
+
+       ret = scan_set_current(scan, jref(node), 0, NULL);
+       if (ret != 0) {
+               return ret;
+       }
+
+       return scan_common(scan, NULL);
+}
+
+/* Common code to perform left or right scanning. */
+static int scan_common(flush_scan * scan, flush_scan * other)
+{
+       int ret;
+
+       assert("nikita-2376", scan->node != NULL);
+       assert("edward-54", jnode_is_unformatted(scan->node)
+              || jnode_is_znode(scan->node));
+
+       /* Special case for starting at an unformatted node.  Optimization: we only want
+          to search for the parent (which requires a tree traversal) once.  Obviously, we
+          shouldn't have to call it once for the left scan and once for the right scan.
+          For this reason, if we search for the parent during scan-left we then duplicate
+          the coord/lock/load into the scan-right object. */
+       if (jnode_is_unformatted(scan->node)) {
+               ret = scan_unformatted(scan, other);
+               if (ret != 0)
+                       return ret;
+       }
+       /* This loop expects to start at a formatted position and performs chaining of
+          formatted regions */
+       while (!reiser4_scan_finished(scan)) {
+
+               ret = scan_formatted(scan);
+               if (ret != 0) {
+                       return ret;
+               }
+       }
+
+       return 0;
+}
+
+static int scan_unformatted(flush_scan * scan, flush_scan * other)
+{
+       int ret = 0;
+       int try = 0;
+
+       if (!coord_is_invalid(&scan->parent_coord))
+               goto scan;
+
+       /* set parent coord from */
+       if (!jnode_is_unformatted(scan->node)) {
+               /* formatted position */
+
+               lock_handle lock;
+               assert("edward-301", jnode_is_znode(scan->node));
+               init_lh(&lock);
+
+               /*
+                * when flush starts from unformatted node, first thing it
+                * does is tree traversal to find formatted parent of starting
+                * node. This parent is then kept lock across scans to the
+                * left and to the right. This means that during scan to the
+                * left we cannot take left-ward lock, because this is
+                * dead-lock prone. So, if we are scanning to the left and
+                * there is already lock held by this thread,
+                * jnode_lock_parent_coord() should use try-lock.
+                */
+               try = reiser4_scanning_left(scan)
+                   && !lock_stack_isclean(get_current_lock_stack());
+               /* Need the node locked to get the parent lock, We have to
+                  take write lock since there is at least one call path
+                  where this znode is already write-locked by us. */
+               ret =
+                   longterm_lock_znode(&lock, JZNODE(scan->node),
+                                       ZNODE_WRITE_LOCK,
+                                       reiser4_scanning_left(scan) ?
+                                       ZNODE_LOCK_LOPRI :
+                                       ZNODE_LOCK_HIPRI);
+               if (ret != 0)
+                       /* EINVAL or E_DEADLOCK here mean... try again!  At this point we've
+                          scanned too far and can't back out, just start over. */
+                       return ret;
+
+               ret = jnode_lock_parent_coord(scan->node,
+                                             &scan->parent_coord,
+                                             &scan->parent_lock,
+                                             &scan->parent_load,
+                                             ZNODE_WRITE_LOCK, try);
+
+               /* FIXME(C): check EINVAL, E_DEADLOCK */
+               done_lh(&lock);
+               if (ret == -E_REPEAT) {
+                       scan->stop = 1;
+                       return 0;
+               }
+               if (ret)
+                       return ret;
+
+       } else {
+               /* unformatted position */
+
+               ret =
+                   jnode_lock_parent_coord(scan->node, &scan->parent_coord,
+                                           &scan->parent_lock,
+                                           &scan->parent_load,
+                                           ZNODE_WRITE_LOCK, try);
+
+               if (IS_CBKERR(ret))
+                       return ret;
+
+               if (ret == CBK_COORD_NOTFOUND)
+                       /* FIXME(C): check EINVAL, E_DEADLOCK */
+                       return ret;
+
+               /* parent was found */
+               assert("jmacd-8661", other != NULL);
+               /* Duplicate the reference into the other flush_scan. */
+               coord_dup(&other->parent_coord, &scan->parent_coord);
+               copy_lh(&other->parent_lock, &scan->parent_lock);
+               copy_load_count(&other->parent_load, &scan->parent_load);
+       }
+      scan:
+       return scan_by_coord(scan);
+}
+
+/* Performs left- or rightward scanning starting from a formatted node. Follow left
+   pointers under tree lock as long as:
+
+   - node->left/right is non-NULL
+   - node->left/right is connected, dirty
+   - node->left/right belongs to the same atom
+   - scan has not reached maximum count
+*/
+static int scan_formatted(flush_scan * scan)
+{
+       int ret;
+       znode *neighbor = NULL;
+
+       assert("jmacd-1401", !reiser4_scan_finished(scan));
+
+       do {
+               znode *node = JZNODE(scan->node);
+
+               /* Node should be connected, but if not stop the scan. */
+               if (!znode_is_connected(node)) {
+                       scan->stop = 1;
+                       break;
+               }
+
+               /* Lock the tree, check-for and reference the next sibling. */
+               read_lock_tree(znode_get_tree(node));
+
+               /* It may be that a node is inserted or removed between a node and its
+                  left sibling while the tree lock is released, but the flush-scan count
+                  does not need to be precise.  Thus, we release the tree lock as soon as
+                  we get the neighboring node. */
+               neighbor =
+                       reiser4_scanning_left(scan) ? node->left : node->right;
+               if (neighbor != NULL) {
+                       zref(neighbor);
+               }
+
+               read_unlock_tree(znode_get_tree(node));
+
+               /* If neighbor is NULL at the leaf level, need to check for an unformatted
+                  sibling using the parent--break in any case. */
+               if (neighbor == NULL) {
+                       break;
+               }
+
+               /* Check the condition for going left, break if it is not met.  This also
+                  releases (jputs) the neighbor if false. */
+               if (!reiser4_scan_goto(scan, ZJNODE(neighbor))) {
+                       break;
+               }
+
+               /* Advance the flush_scan state to the left, repeat. */
+               ret = scan_set_current(scan, ZJNODE(neighbor), 1, NULL);
+               if (ret != 0) {
+                       return ret;
+               }
+
+       } while (!reiser4_scan_finished(scan));
+
+       /* If neighbor is NULL then we reached the end of a formatted region, or else the
+          sibling is out of memory, now check for an extent to the left (as long as
+          LEAF_LEVEL). */
+       if (neighbor != NULL || jnode_get_level(scan->node) != LEAF_LEVEL
+           || reiser4_scan_finished(scan)) {
+               scan->stop = 1;
+               return 0;
+       }
+       /* Otherwise, calls scan_by_coord for the right(left)most item of the
+          left(right) neighbor on the parent level, then possibly continue. */
+
+       coord_init_invalid(&scan->parent_coord, NULL);
+       return scan_unformatted(scan, NULL);
+}
+
+/* NOTE-EDWARD:
+   This scans adjacent items of the same type and calls scan flush plugin for each one.
+   Performs left(right)ward scanning starting from a (possibly) unformatted node.  If we start
+   from unformatted node, then we continue only if the next neighbor is also unformatted.
+   When called from scan_formatted, we skip first iteration (to make sure that
+   right(left)most item of the left(right) neighbor on the parent level is of the same
+   type and set appropriate coord). */
+static int scan_by_coord(flush_scan * scan)
+{
+       int ret = 0;
+       int scan_this_coord;
+       lock_handle next_lock;
+       load_count next_load;
+       coord_t next_coord;
+       jnode *child;
+       item_plugin *iplug;
+
+       init_lh(&next_lock);
+       init_load_count(&next_load);
+       scan_this_coord = (jnode_is_unformatted(scan->node) ? 1 : 0);
+
+       /* set initial item id */
+       iplug = item_plugin_by_coord(&scan->parent_coord);
+
+       for (; !reiser4_scan_finished(scan); scan_this_coord = 1) {
+               if (scan_this_coord) {
+                       /* Here we expect that unit is scannable. it would not be so due
+                        * to race with extent->tail conversion.  */
+                       if (iplug->f.scan == NULL) {
+                               scan->stop = 1;
+                               ret = -E_REPEAT;
+                               /* skip the check at the end. */
+                               goto race;
+                       }
+
+                       ret = iplug->f.scan(scan);
+                       if (ret != 0)
+                               goto exit;
+
+                       if (reiser4_scan_finished(scan)) {
+                               checkchild(scan);
+                               break;
+                       }
+               } else {
+                       /* the same race against truncate as above is possible
+                        * here, it seems */
+
+                       /* NOTE-JMACD: In this case, apply the same end-of-node logic but don't scan
+                          the first coordinate. */
+                       assert("jmacd-1231",
+                              item_is_internal(&scan->parent_coord));
+               }
+
+               if (iplug->f.utmost_child == NULL
+                   || znode_get_level(scan->parent_coord.node) != TWIG_LEVEL) {
+                       /* stop this coord and continue on parrent level */
+                       ret =
+                           scan_set_current(scan,
+                                            ZJNODE(zref
+                                                   (scan->parent_coord.node)),
+                                            1, NULL);
+                       if (ret != 0)
+                               goto exit;
+                       break;
+               }
+
+               /* Either way, the invariant is that scan->parent_coord is set to the
+                  parent of scan->node. Now get the next unit. */
+               coord_dup(&next_coord, &scan->parent_coord);
+               coord_sideof_unit(&next_coord, scan->direction);
+
+               /* If off-the-end of the twig, try the next twig. */
+               if (coord_is_after_sideof_unit(&next_coord, scan->direction)) {
+                       /* We take the write lock because we may start flushing from this
+                        * coordinate. */
+                       ret =
+                           neighbor_in_slum(next_coord.node, &next_lock,
+                                            scan->direction, ZNODE_WRITE_LOCK,
+                                            1 /* check dirty */ );
+                       if (ret == -E_NO_NEIGHBOR) {
+                               scan->stop = 1;
+                               ret = 0;
+                               break;
+                       }
+
+                       if (ret != 0) {
+                               goto exit;
+                       }
+
+                       ret = incr_load_count_znode(&next_load, next_lock.node);
+                       if (ret != 0) {
+                               goto exit;
+                       }
+
+                       coord_init_sideof_unit(&next_coord, next_lock.node,
+                                              sideof_reverse(scan->direction));
+               }
+
+               iplug = item_plugin_by_coord(&next_coord);
+
+               /* Get the next child. */
+               ret =
+                   iplug->f.utmost_child(&next_coord,
+                                         sideof_reverse(scan->direction),
+                                         &child);
+               if (ret != 0)
+                       goto exit;
+               /* If the next child is not in memory, or, item_utmost_child
+                  failed (due to race with unlink, most probably), stop
+                  here. */
+               if (child == NULL || IS_ERR(child)) {
+                       scan->stop = 1;
+                       checkchild(scan);
+                       break;
+               }
+
+               assert("nikita-2374", jnode_is_unformatted(child)
+                      || jnode_is_znode(child));
+
+               /* See if it is dirty, part of the same atom. */
+               if (!reiser4_scan_goto(scan, child)) {
+                       checkchild(scan);
+                       break;
+               }
+
+               /* If so, make this child current. */
+               ret = scan_set_current(scan, child, 1, &next_coord);
+               if (ret != 0)
+                       goto exit;
+
+               /* Now continue.  If formatted we release the parent lock and return, then
+                  proceed. */
+               if (jnode_is_znode(child))
+                       break;
+
+               /* Otherwise, repeat the above loop with next_coord. */
+               if (next_load.node != NULL) {
+                       done_lh(&scan->parent_lock);
+                       move_lh(&scan->parent_lock, &next_lock);
+                       move_load_count(&scan->parent_load, &next_load);
+               }
+       }
+
+       assert("jmacd-6233",
+              reiser4_scan_finished(scan) || jnode_is_znode(scan->node));
+      exit:
+       checkchild(scan);
+      race:                    /* skip the above check  */
+       if (jnode_is_znode(scan->node)) {
+               done_lh(&scan->parent_lock);
+               done_load_count(&scan->parent_load);
+       }
+
+       done_load_count(&next_load);
+       done_lh(&next_lock);
+       return ret;
+}
+
+/* FLUSH POS HELPERS */
+
+/* Initialize the fields of a flush_position. */
+static void pos_init(flush_pos_t * pos)
+{
+       memset(pos, 0, sizeof *pos);
+
+       pos->state = POS_INVALID;
+       coord_init_invalid(&pos->coord, NULL);
+       init_lh(&pos->lock);
+       init_load_count(&pos->load);
+
+       reiser4_blocknr_hint_init(&pos->preceder);
+}
+
+/* The flush loop inside squalloc periodically checks pos_valid to
+   determine when "enough flushing" has been performed.  This will return true until one
+   of the following conditions is met:
+
+   1. the number of flush-queued nodes has reached the kernel-supplied "int *nr_to_flush"
+   parameter, meaning we have flushed as many blocks as the kernel requested.  When
+   flushing to commit, this parameter is NULL.
+
+   2. pos_stop() is called because squalloc discovers that the "next" node in the
+   flush order is either non-existant, not dirty, or not in the same atom.
+*/
+
+static int pos_valid(flush_pos_t * pos)
+{
+       return pos->state != POS_INVALID;
+}
+
+/* Release any resources of a flush_position.  Called when jnode_flush finishes. */
+static void pos_done(flush_pos_t * pos)
+{
+       pos_stop(pos);
+       reiser4_blocknr_hint_done(&pos->preceder);
+       if (convert_data(pos))
+               free_convert_data(pos);
+}
+
+/* Reset the point and parent.  Called during flush subroutines to terminate the
+   squalloc loop. */
+static int pos_stop(flush_pos_t * pos)
+{
+       pos->state = POS_INVALID;
+       done_lh(&pos->lock);
+       done_load_count(&pos->load);
+       coord_init_invalid(&pos->coord, NULL);
+
+       if (pos->child) {
+               jput(pos->child);
+               pos->child = NULL;
+       }
+
+       return 0;
+}
+
+/* Return the flush_position's block allocator hint. */
+reiser4_blocknr_hint *reiser4_pos_hint(flush_pos_t * pos)
+{
+       return &pos->preceder;
+}
+
+flush_queue_t * reiser4_pos_fq(flush_pos_t * pos)
+{
+       return pos->fq;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 90
+   LocalWords:  preceder
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/flush.h linux-2.6.20/fs/reiser4/flush.h
--- linux-2.6.20.orig/fs/reiser4/flush.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/flush.h     2007-05-06 14:50:43.718981974 +0400
@@ -0,0 +1,274 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* DECLARATIONS: */
+
+#if !defined(__REISER4_FLUSH_H__)
+#define __REISER4_FLUSH_H__
+
+#include "plugin/cluster.h"
+
+/* The flush_scan data structure maintains the state of an in-progress flush-scan on a
+   single level of the tree.  A flush-scan is used for counting the number of adjacent
+   nodes to flush, which is used to determine whether we should relocate, and it is also
+   used to find a starting point for flush.  A flush-scan object can scan in both right
+   and left directions via the scan_left() and scan_right() interfaces.  The
+   right- and left-variations are similar but perform different functions.  When scanning
+   left we (optionally perform rapid scanning and then) longterm-lock the endpoint node.
+   When scanning right we are simply counting the number of adjacent, dirty nodes. */
+struct flush_scan {
+
+       /* The current number of nodes scanned on this level. */
+       unsigned count;
+
+       /* There may be a maximum number of nodes for a scan on any single level.  When
+          going leftward, max_count is determined by FLUSH_SCAN_MAXNODES (see reiser4.h) */
+       unsigned max_count;
+
+       /* Direction: Set to one of the sideof enumeration: { LEFT_SIDE, RIGHT_SIDE }. */
+       sideof direction;
+
+       /* Initially @stop is set to false then set true once some condition stops the
+          search (e.g., we found a clean node before reaching max_count or we found a
+          node belonging to another atom). */
+       int stop;
+
+       /* The current scan position.  If @node is non-NULL then its reference count has
+          been incremented to reflect this reference. */
+       jnode *node;
+
+       /* A handle for zload/zrelse of current scan position node. */
+       load_count node_load;
+
+       /* During left-scan, if the final position (a.k.a. endpoint node) is formatted the
+          node is locked using this lock handle.  The endpoint needs to be locked for
+          transfer to the flush_position object after scanning finishes. */
+       lock_handle node_lock;
+
+       /* When the position is unformatted, its parent, coordinate, and parent
+          zload/zrelse handle. */
+       lock_handle parent_lock;
+       coord_t parent_coord;
+       load_count parent_load;
+
+       /* The block allocator preceder hint.  Sometimes flush_scan determines what the
+          preceder is and if so it sets it here, after which it is copied into the
+          flush_position.  Otherwise, the preceder is computed later. */
+       reiser4_block_nr preceder_blk;
+};
+
+typedef struct convert_item_info {
+       dc_item_stat d_cur;     /* disk cluster state of the current item */
+       dc_item_stat d_next;    /* disk cluster state of the next slum item */
+       struct inode *inode;
+       flow_t flow;
+} convert_item_info_t;
+
+typedef struct convert_info {
+       int count;              /* for squalloc terminating */
+       reiser4_cluster_t clust;        /* transform cluster */
+       item_plugin *iplug;     /* current item plugin */
+       convert_item_info_t *itm;       /* current item info */
+} convert_info_t;
+
+typedef enum flush_position_state {
+       POS_INVALID,            /* Invalid or stopped pos, do not continue slum
+                                * processing */
+       POS_ON_LEAF,            /* pos points to already prepped, locked formatted node at
+                                * leaf level */
+       POS_ON_EPOINT,          /* pos keeps a lock on twig level, "coord" field is used
+                                * to traverse unformatted nodes */
+       POS_TO_LEAF,            /* pos is being moved to leaf level */
+       POS_TO_TWIG,            /* pos is being moved to twig level */
+       POS_END_OF_TWIG,        /* special case of POS_ON_TWIG, when coord is after
+                                * rightmost unit of the current twig */
+       POS_ON_INTERNAL         /* same as POS_ON_LEAF, but points to internal node */
+} flushpos_state_t;
+
+/* An encapsulation of the current flush point and all the parameters that are passed
+   through the entire squeeze-and-allocate stage of the flush routine.  A single
+   flush_position object is constructed after left- and right-scanning finishes. */
+struct flush_position {
+       flushpos_state_t state;
+
+       coord_t coord;          /* coord to traverse unformatted nodes */
+       lock_handle lock;       /* current lock we hold */
+       load_count load;        /* load status for current locked formatted node  */
+
+       jnode *child;           /* for passing a reference to unformatted child
+                                * across pos state changes */
+
+       reiser4_blocknr_hint preceder;  /* The flush 'hint' state. */
+       int leaf_relocate;      /* True if enough leaf-level nodes were
+                                * found to suggest a relocate policy. */
+       int alloc_cnt;          /* The number of nodes allocated during squeeze and allococate. */
+       int prep_or_free_cnt;   /* The number of nodes prepared for write (allocate) or squeezed and freed. */
+       flush_queue_t *fq;
+       long *nr_written;       /* number of nodes submitted to disk */
+       int flags;              /* a copy of jnode_flush flags argument */
+
+       znode *prev_twig;       /* previous parent pointer value, used to catch
+                                * processing of new twig node */
+       convert_info_t *sq;     /* convert info */
+
+       unsigned long pos_in_unit;      /* for extents only. Position
+                                          within an extent unit of first
+                                          jnode of slum */
+       long nr_to_write;       /* number of unformatted nodes to handle on flush */
+};
+
+static inline int item_convert_count(flush_pos_t * pos)
+{
+       return pos->sq->count;
+}
+static inline void inc_item_convert_count(flush_pos_t * pos)
+{
+       pos->sq->count++;
+}
+static inline void set_item_convert_count(flush_pos_t * pos, int count)
+{
+       pos->sq->count = count;
+}
+static inline item_plugin *item_convert_plug(flush_pos_t * pos)
+{
+       return pos->sq->iplug;
+}
+
+static inline convert_info_t *convert_data(flush_pos_t * pos)
+{
+       return pos->sq;
+}
+
+static inline convert_item_info_t *item_convert_data(flush_pos_t * pos)
+{
+       assert("edward-955", convert_data(pos));
+       return pos->sq->itm;
+}
+
+static inline tfm_cluster_t *tfm_cluster_sq(flush_pos_t * pos)
+{
+       return &pos->sq->clust.tc;
+}
+
+static inline tfm_stream_t *tfm_stream_sq(flush_pos_t * pos, tfm_stream_id id)
+{
+       assert("edward-854", pos->sq != NULL);
+       return tfm_stream(tfm_cluster_sq(pos), id);
+}
+
+static inline int chaining_data_present(flush_pos_t * pos)
+{
+       return convert_data(pos) && item_convert_data(pos);
+}
+
+/* Returns true if next node contains next item of the disk cluster
+   so item convert data should be moved to the right slum neighbor.
+*/
+static inline int should_chain_next_node(flush_pos_t * pos)
+{
+       int result = 0;
+
+       assert("edward-1007", chaining_data_present(pos));
+
+       switch (item_convert_data(pos)->d_next) {
+       case DC_CHAINED_ITEM:
+               result = 1;
+               break;
+       case DC_AFTER_CLUSTER:
+               break;
+       default:
+               impossible("edward-1009", "bad state of next slum item");
+       }
+       return result;
+}
+
+/* update item state in a disk cluster to assign conversion mode */
+static inline void
+move_chaining_data(flush_pos_t * pos, int this_node /* where is next item */ )
+{
+
+       assert("edward-1010", chaining_data_present(pos));
+
+       if (this_node == 0) {
+               /* next item is on the right neighbor */
+               assert("edward-1011",
+                      item_convert_data(pos)->d_cur == DC_FIRST_ITEM ||
+                      item_convert_data(pos)->d_cur == DC_CHAINED_ITEM);
+               assert("edward-1012",
+                      item_convert_data(pos)->d_next == DC_CHAINED_ITEM);
+
+               item_convert_data(pos)->d_cur = DC_CHAINED_ITEM;
+               item_convert_data(pos)->d_next = DC_INVALID_STATE;
+       } else {
+               /* next item is on the same node */
+               assert("edward-1013",
+                      item_convert_data(pos)->d_cur == DC_FIRST_ITEM ||
+                      item_convert_data(pos)->d_cur == DC_CHAINED_ITEM);
+               assert("edward-1227",
+                      item_convert_data(pos)->d_next == DC_AFTER_CLUSTER ||
+                      item_convert_data(pos)->d_next == DC_INVALID_STATE);
+
+               item_convert_data(pos)->d_cur = DC_AFTER_CLUSTER;
+               item_convert_data(pos)->d_next = DC_INVALID_STATE;
+       }
+}
+
+static inline int should_convert_node(flush_pos_t * pos, znode * node)
+{
+       return znode_convertible(node);
+}
+
+/* true if there is attached convert item info */
+static inline int should_convert_next_node(flush_pos_t * pos, znode * node)
+{
+       return convert_data(pos) && item_convert_data(pos);
+}
+
+#define SQUALLOC_THRESHOLD 256
+
+static inline int should_terminate_squalloc(flush_pos_t * pos)
+{
+       return convert_data(pos) &&
+           !item_convert_data(pos) &&
+           item_convert_count(pos) >= SQUALLOC_THRESHOLD;
+}
+
+void free_convert_data(flush_pos_t * pos);
+/* used in extent.c */
+int scan_set_current(flush_scan * scan, jnode * node, unsigned add_size,
+                    const coord_t * parent);
+int reiser4_scan_finished(flush_scan * scan);
+int reiser4_scanning_left(flush_scan * scan);
+int reiser4_scan_goto(flush_scan * scan, jnode * tonode);
+txn_atom *atom_locked_by_fq(flush_queue_t * fq);
+int reiser4_alloc_extent(flush_pos_t *flush_pos);
+squeeze_result squalloc_extent(znode *left, const coord_t *, flush_pos_t *,
+                              reiser4_key *stop_key);
+extern int reiser4_init_fqs(void);
+extern void reiser4_done_fqs(void);
+
+#if REISER4_DEBUG
+
+extern void reiser4_check_fq(const txn_atom *atom);
+extern atomic_t flush_cnt;
+
+#define check_preceder(blk) \
+assert("nikita-2588", blk < reiser4_block_count(reiser4_get_current_sb()));
+extern void check_pos(flush_pos_t * pos);
+#else
+#define check_preceder(b) noop
+#define check_pos(pos) noop
+#endif
+
+/* __REISER4_FLUSH_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 90
+   LocalWords:  preceder
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/flush_queue.c linux-2.6.20/fs/reiser4/flush_queue.c
--- linux-2.6.20.orig/fs/reiser4/flush_queue.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/flush_queue.c       2007-05-06 14:50:43.718981974 +0400
@@ -0,0 +1,680 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "debug.h"
+#include "super.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "page_cache.h"
+#include "wander.h"
+#include "vfs_ops.h"
+#include "writeout.h"
+#include "flush.h"
+
+#include <linux/bio.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/blkdev.h>
+#include <linux/writeback.h>
+
+/* A flush queue object is an accumulator for keeping jnodes prepared
+   by the jnode_flush() function for writing to disk. Those "queued" jnodes are
+   kept on the flush queue until memory pressure or atom commit asks
+   flush queues to write some or all from their jnodes. */
+
+/*
+   LOCKING:
+
+   fq->guard spin lock protects fq->atom pointer and nothing else.  fq->prepped
+   list protected by atom spin lock.  fq->prepped list uses the following
+   locking:
+
+   two ways to protect fq->prepped list for read-only list traversal:
+
+   1. atom spin-lock atom.
+   2. fq is IN_USE, atom->nr_running_queues increased.
+
+   and one for list modification:
+
+   1. atom is spin-locked and one condition is true: fq is IN_USE or
+      atom->nr_running_queues == 0.
+
+   The deadlock-safe order for flush queues and atoms is: first lock atom, then
+   lock flush queue, then lock jnode.
+*/
+
+#define fq_in_use(fq)          ((fq)->state & FQ_IN_USE)
+#define fq_ready(fq)           (!fq_in_use(fq))
+
+#define mark_fq_in_use(fq)     do { (fq)->state |= FQ_IN_USE;    } while (0)
+#define mark_fq_ready(fq)      do { (fq)->state &= ~FQ_IN_USE;   } while (0)
+
+/* get lock on atom from locked flush queue object */
+static txn_atom *atom_locked_by_fq_nolock(flush_queue_t * fq)
+{
+       /* This code is similar to jnode_get_atom(), look at it for the
+        * explanation. */
+       txn_atom *atom;
+
+       assert_spin_locked(&(fq->guard));
+
+       while (1) {
+               atom = fq->atom;
+               if (atom == NULL)
+                       break;
+
+               if (spin_trylock_atom(atom))
+                       break;
+
+               atomic_inc(&atom->refcount);
+               spin_unlock(&(fq->guard));
+               spin_lock_atom(atom);
+               spin_lock(&(fq->guard));
+
+               if (fq->atom == atom) {
+                       atomic_dec(&atom->refcount);
+                       break;
+               }
+
+               spin_unlock(&(fq->guard));
+               atom_dec_and_unlock(atom);
+               spin_lock(&(fq->guard));
+       }
+
+       return atom;
+}
+
+txn_atom *atom_locked_by_fq(flush_queue_t * fq)
+{
+       txn_atom *atom;
+
+       spin_lock(&(fq->guard));
+       atom = atom_locked_by_fq_nolock(fq);
+       spin_unlock(&(fq->guard));
+       return atom;
+}
+
+static void init_fq(flush_queue_t * fq)
+{
+       memset(fq, 0, sizeof *fq);
+
+       atomic_set(&fq->nr_submitted, 0);
+
+       INIT_LIST_HEAD(ATOM_FQ_LIST(fq));
+
+       init_waitqueue_head(&fq->wait);
+       spin_lock_init(&fq->guard);
+}
+
+/* slab for flush queues */
+static struct kmem_cache *fq_slab;
+
+/**
+ * reiser4_init_fqs - create flush queue cache
+ *
+ * Initializes slab cache of flush queues. It is part of reiser4 module
+ * initialization.
+ */
+int reiser4_init_fqs(void)
+{
+       fq_slab = kmem_cache_create("fq",
+                                   sizeof(flush_queue_t),
+                                   0, SLAB_HWCACHE_ALIGN, NULL, NULL);
+       if (fq_slab == NULL)
+               return RETERR(-ENOMEM);
+       return 0;
+}
+
+/**
+ * reiser4_done_fqs - delete flush queue cache
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void reiser4_done_fqs(void)
+{
+       destroy_reiser4_cache(&fq_slab);
+}
+
+/* create new flush queue object */
+static flush_queue_t *create_fq(gfp_t gfp)
+{
+       flush_queue_t *fq;
+
+       fq = kmem_cache_alloc(fq_slab, gfp);
+       if (fq)
+               init_fq(fq);
+
+       return fq;
+}
+
+/* adjust atom's and flush queue's counters of queued nodes */
+static void count_enqueued_node(flush_queue_t * fq)
+{
+       ON_DEBUG(fq->atom->num_queued++);
+}
+
+static void count_dequeued_node(flush_queue_t * fq)
+{
+       assert("zam-993", fq->atom->num_queued > 0);
+       ON_DEBUG(fq->atom->num_queued--);
+}
+
+/* attach flush queue object to the atom */
+static void attach_fq(txn_atom *atom, flush_queue_t *fq)
+{
+       assert_spin_locked(&(atom->alock));
+       list_add(&fq->alink, &atom->flush_queues);
+       fq->atom = atom;
+       ON_DEBUG(atom->nr_flush_queues++);
+}
+
+static void detach_fq(flush_queue_t * fq)
+{
+       assert_spin_locked(&(fq->atom->alock));
+
+       spin_lock(&(fq->guard));
+       list_del_init(&fq->alink);
+       assert("vs-1456", fq->atom->nr_flush_queues > 0);
+       ON_DEBUG(fq->atom->nr_flush_queues--);
+       fq->atom = NULL;
+       spin_unlock(&(fq->guard));
+}
+
+/* destroy flush queue object */
+static void done_fq(flush_queue_t * fq)
+{
+       assert("zam-763", list_empty_careful(ATOM_FQ_LIST(fq)));
+       assert("zam-766", atomic_read(&fq->nr_submitted) == 0);
+
+       kmem_cache_free(fq_slab, fq);
+}
+
+/* */
+static void mark_jnode_queued(flush_queue_t * fq, jnode * node)
+{
+       JF_SET(node, JNODE_FLUSH_QUEUED);
+       count_enqueued_node(fq);
+}
+
+/* Putting jnode into the flush queue. Both atom and jnode should be
+   spin-locked. */
+void queue_jnode(flush_queue_t * fq, jnode * node)
+{
+       assert_spin_locked(&(node->guard));
+       assert("zam-713", node->atom != NULL);
+       assert_spin_locked(&(node->atom->alock));
+       assert("zam-716", fq->atom != NULL);
+       assert("zam-717", fq->atom == node->atom);
+       assert("zam-907", fq_in_use(fq));
+
+       assert("zam-714", JF_ISSET(node, JNODE_DIRTY));
+       assert("zam-826", JF_ISSET(node, JNODE_RELOC));
+       assert("vs-1481", !JF_ISSET(node, JNODE_FLUSH_QUEUED));
+       assert("vs-1481", NODE_LIST(node) != FQ_LIST);
+
+       mark_jnode_queued(fq, node);
+       list_move_tail(&node->capture_link, ATOM_FQ_LIST(fq));
+
+       ON_DEBUG(count_jnode(node->atom, node, NODE_LIST(node),
+                            FQ_LIST, 1));
+}
+
+/* repeatable process for waiting io completion on a flush queue object */
+static int wait_io(flush_queue_t * fq, int *nr_io_errors)
+{
+       assert("zam-738", fq->atom != NULL);
+       assert_spin_locked(&(fq->atom->alock));
+       assert("zam-736", fq_in_use(fq));
+       assert("zam-911", list_empty_careful(ATOM_FQ_LIST(fq)));
+
+       if (atomic_read(&fq->nr_submitted) != 0) {
+               struct super_block *super;
+
+               spin_unlock_atom(fq->atom);
+
+               assert("nikita-3013", reiser4_schedulable());
+
+               super = reiser4_get_current_sb();
+
+               /* FIXME: this is instead of blk_run_queues() */
+               blk_run_address_space(reiser4_get_super_fake(super)->i_mapping);
+
+               if (!(super->s_flags & MS_RDONLY))
+                       wait_event(fq->wait, atomic_read(&fq->nr_submitted) == 0);
+
+               /* Ask the caller to re-acquire the locks and call this
+                  function again. Note: this technique is commonly used in
+                  the txnmgr code. */
+               return -E_REPEAT;
+       }
+
+       *nr_io_errors += atomic_read(&fq->nr_errors);
+       return 0;
+}
+
+/* wait on I/O completion, re-submit dirty nodes to write */
+static int finish_fq(flush_queue_t * fq, int *nr_io_errors)
+{
+       int ret;
+       txn_atom *atom = fq->atom;
+
+       assert("zam-801", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+       assert("zam-762", fq_in_use(fq));
+
+       ret = wait_io(fq, nr_io_errors);
+       if (ret)
+               return ret;
+
+       detach_fq(fq);
+       done_fq(fq);
+
+       reiser4_atom_send_event(atom);
+
+       return 0;
+}
+
+/* wait for all i/o for given atom to be completed, actually do one iteration
+   on that and return -E_REPEAT if there more iterations needed */
+static int finish_all_fq(txn_atom * atom, int *nr_io_errors)
+{
+       flush_queue_t *fq;
+
+       assert_spin_locked(&(atom->alock));
+
+       if (list_empty_careful(&atom->flush_queues))
+               return 0;
+
+       list_for_each_entry(fq, &atom->flush_queues, alink) {
+               if (fq_ready(fq)) {
+                       int ret;
+
+                       mark_fq_in_use(fq);
+                       assert("vs-1247", fq->owner == NULL);
+                       ON_DEBUG(fq->owner = current);
+                       ret = finish_fq(fq, nr_io_errors);
+
+                       if (*nr_io_errors)
+                               reiser4_handle_error();
+
+                       if (ret) {
+                               reiser4_fq_put(fq);
+                               return ret;
+                       }
+
+                       spin_unlock_atom(atom);
+
+                       return -E_REPEAT;
+               }
+       }
+
+       /* All flush queues are in use; atom remains locked */
+       return -EBUSY;
+}
+
+/* wait all i/o for current atom */
+int current_atom_finish_all_fq(void)
+{
+       txn_atom *atom;
+       int nr_io_errors = 0;
+       int ret = 0;
+
+       do {
+               while (1) {
+                       atom = get_current_atom_locked();
+                       ret = finish_all_fq(atom, &nr_io_errors);
+                       if (ret != -EBUSY)
+                               break;
+                       reiser4_atom_wait_event(atom);
+               }
+       } while (ret == -E_REPEAT);
+
+       /* we do not need locked atom after this function finishes, SUCCESS or
+          -EBUSY are two return codes when atom remains locked after
+          finish_all_fq */
+       if (!ret)
+               spin_unlock_atom(atom);
+
+       assert_spin_not_locked(&(atom->alock));
+
+       if (ret)
+               return ret;
+
+       if (nr_io_errors)
+               return RETERR(-EIO);
+
+       return 0;
+}
+
+/* change node->atom field for all jnode from given list */
+static void
+scan_fq_and_update_atom_ref(struct list_head *list, txn_atom *atom)
+{
+       jnode *cur;
+
+       list_for_each_entry(cur, list, capture_link) {
+               spin_lock_jnode(cur);
+               cur->atom = atom;
+               spin_unlock_jnode(cur);
+       }
+}
+
+/* support for atom fusion operation */
+void reiser4_fuse_fq(txn_atom *to, txn_atom *from)
+{
+       flush_queue_t *fq;
+
+       assert_spin_locked(&(to->alock));
+       assert_spin_locked(&(from->alock));
+
+       list_for_each_entry(fq, &from->flush_queues, alink) {
+               scan_fq_and_update_atom_ref(ATOM_FQ_LIST(fq), to);
+               spin_lock(&(fq->guard));
+               fq->atom = to;
+               spin_unlock(&(fq->guard));
+       }
+
+       list_splice_init(&from->flush_queues, to->flush_queues.prev);
+
+#if REISER4_DEBUG
+       to->num_queued += from->num_queued;
+       to->nr_flush_queues += from->nr_flush_queues;
+       from->nr_flush_queues = 0;
+#endif
+}
+
+#if REISER4_DEBUG
+int atom_fq_parts_are_clean(txn_atom * atom)
+{
+       assert("zam-915", atom != NULL);
+       return list_empty_careful(&atom->flush_queues);
+}
+#endif
+/* Bio i/o completion routine for reiser4 write operations. */
+static int
+end_io_handler(struct bio *bio, unsigned int bytes_done UNUSED_ARG,
+              int err)
+{
+       int i;
+       int nr_errors = 0;
+       flush_queue_t *fq;
+
+       assert("zam-958", bio->bi_rw & WRITE);
+
+       /* i/o op. is not fully completed */
+       if (bio->bi_size != 0)
+               return 1;
+
+       if (err == -EOPNOTSUPP)
+               set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+
+       /* we expect that bio->private is set to NULL or fq object which is used
+        * for synchronization and error counting. */
+       fq = bio->bi_private;
+       /* Check all elements of io_vec for correct write completion. */
+       for (i = 0; i < bio->bi_vcnt; i += 1) {
+               struct page *pg = bio->bi_io_vec[i].bv_page;
+
+               if (!test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+                       SetPageError(pg);
+                       nr_errors++;
+               }
+
+               {
+                       /* jnode WRITEBACK ("write is in progress bit") is
+                        * atomically cleared here. */
+                       jnode *node;
+
+                       assert("zam-736", pg != NULL);
+                       assert("zam-736", PagePrivate(pg));
+                       node = jprivate(pg);
+
+                       JF_CLR(node, JNODE_WRITEBACK);
+               }
+
+               end_page_writeback(pg);
+               page_cache_release(pg);
+       }
+
+       if (fq) {
+               /* count i/o error in fq object */
+               atomic_add(nr_errors, &fq->nr_errors);
+
+               /* If all write requests registered in this "fq" are done we up
+                * the waiter. */
+               if (atomic_sub_and_test(bio->bi_vcnt, &fq->nr_submitted))
+                       wake_up(&fq->wait);
+       }
+
+       bio_put(bio);
+       return 0;
+}
+
+/* Count I/O requests which will be submitted by @bio in given flush queues
+   @fq */
+void add_fq_to_bio(flush_queue_t * fq, struct bio *bio)
+{
+       bio->bi_private = fq;
+       bio->bi_end_io = end_io_handler;
+
+       if (fq)
+               atomic_add(bio->bi_vcnt, &fq->nr_submitted);
+}
+
+/* Move all queued nodes out from @fq->prepped list. */
+static void release_prepped_list(flush_queue_t * fq)
+{
+       txn_atom *atom;
+
+       assert("zam-904", fq_in_use(fq));
+       atom = atom_locked_by_fq(fq);
+
+       while (!list_empty(ATOM_FQ_LIST(fq))) {
+               jnode *cur;
+
+               cur = list_entry(ATOM_FQ_LIST(fq)->next, jnode, capture_link);
+               list_del_init(&cur->capture_link);
+
+               count_dequeued_node(fq);
+               spin_lock_jnode(cur);
+               assert("nikita-3154", !JF_ISSET(cur, JNODE_OVRWR));
+               assert("nikita-3154", JF_ISSET(cur, JNODE_RELOC));
+               assert("nikita-3154", JF_ISSET(cur, JNODE_FLUSH_QUEUED));
+               JF_CLR(cur, JNODE_FLUSH_QUEUED);
+
+               if (JF_ISSET(cur, JNODE_DIRTY)) {
+                       list_add_tail(&cur->capture_link,
+                                     ATOM_DIRTY_LIST(atom, jnode_get_level(cur)));
+                       ON_DEBUG(count_jnode(atom, cur, FQ_LIST,
+                                            DIRTY_LIST, 1));
+               } else {
+                       list_add_tail(&cur->capture_link, ATOM_CLEAN_LIST(atom));
+                       ON_DEBUG(count_jnode(atom, cur, FQ_LIST,
+                                            CLEAN_LIST, 1));
+               }
+
+               spin_unlock_jnode(cur);
+       }
+
+       if (--atom->nr_running_queues == 0)
+               reiser4_atom_send_event(atom);
+
+       spin_unlock_atom(atom);
+}
+
+/* Submit write requests for nodes on the already filled flush queue @fq.
+
+   @fq: flush queue object which contains jnodes we can (and will) write.
+   @return: number of submitted blocks (>=0) if success, otherwise -- an error
+            code (<0). */
+int reiser4_write_fq(flush_queue_t * fq, long *nr_submitted, int flags)
+{
+       int ret;
+       txn_atom *atom;
+
+       while (1) {
+               atom = atom_locked_by_fq(fq);
+               assert("zam-924", atom);
+               /* do not write fq in parallel. */
+               if (atom->nr_running_queues == 0
+                   || !(flags & WRITEOUT_SINGLE_STREAM))
+                       break;
+               reiser4_atom_wait_event(atom);
+       }
+
+       atom->nr_running_queues++;
+       spin_unlock_atom(atom);
+
+       ret = write_jnode_list(ATOM_FQ_LIST(fq), fq, nr_submitted, flags);
+       release_prepped_list(fq);
+
+       return ret;
+}
+
+/* Getting flush queue object for exclusive use by one thread. May require
+   several iterations which is indicated by -E_REPEAT return code.
+
+   This function does not contain code for obtaining an atom lock because an
+   atom lock is obtained by different ways in different parts of reiser4,
+   usually it is current atom, but we need a possibility for getting fq for the
+   atom of given jnode. */
+static int fq_by_atom_gfp(txn_atom *atom, flush_queue_t **new_fq, gfp_t gfp)
+{
+       flush_queue_t *fq;
+
+       assert_spin_locked(&(atom->alock));
+
+       fq = list_entry(atom->flush_queues.next, flush_queue_t, alink);
+       while (&atom->flush_queues != &fq->alink) {
+               spin_lock(&(fq->guard));
+
+               if (fq_ready(fq)) {
+                       mark_fq_in_use(fq);
+                       assert("vs-1246", fq->owner == NULL);
+                       ON_DEBUG(fq->owner = current);
+                       spin_unlock(&(fq->guard));
+
+                       if (*new_fq)
+                               done_fq(*new_fq);
+
+                       *new_fq = fq;
+
+                       return 0;
+               }
+
+               spin_unlock(&(fq->guard));
+
+               fq = list_entry(fq->alink.next, flush_queue_t, alink);
+       }
+
+       /* Use previously allocated fq object */
+       if (*new_fq) {
+               mark_fq_in_use(*new_fq);
+               assert("vs-1248", (*new_fq)->owner == 0);
+               ON_DEBUG((*new_fq)->owner = current);
+               attach_fq(atom, *new_fq);
+
+               return 0;
+       }
+
+       spin_unlock_atom(atom);
+
+       *new_fq = create_fq(gfp);
+
+       if (*new_fq == NULL)
+               return RETERR(-ENOMEM);
+
+       return RETERR(-E_REPEAT);
+}
+
+int reiser4_fq_by_atom(txn_atom * atom, flush_queue_t ** new_fq)
+{
+       return fq_by_atom_gfp(atom, new_fq, reiser4_ctx_gfp_mask_get());
+}
+
+/* A wrapper around reiser4_fq_by_atom for getting a flush queue
+   object for current atom, if success fq->atom remains locked. */
+flush_queue_t *get_fq_for_current_atom(void)
+{
+       flush_queue_t *fq = NULL;
+       txn_atom *atom;
+       int ret;
+
+       do {
+               atom = get_current_atom_locked();
+               ret = reiser4_fq_by_atom(atom, &fq);
+       } while (ret == -E_REPEAT);
+
+       if (ret)
+               return ERR_PTR(ret);
+       return fq;
+}
+
+/* Releasing flush queue object after exclusive use */
+void reiser4_fq_put_nolock(flush_queue_t *fq)
+{
+       assert("zam-747", fq->atom != NULL);
+       assert("zam-902", list_empty_careful(ATOM_FQ_LIST(fq)));
+       mark_fq_ready(fq);
+       assert("vs-1245", fq->owner == current);
+       ON_DEBUG(fq->owner = NULL);
+}
+
+void reiser4_fq_put(flush_queue_t * fq)
+{
+       txn_atom *atom;
+
+       spin_lock(&(fq->guard));
+       atom = atom_locked_by_fq_nolock(fq);
+
+       assert("zam-746", atom != NULL);
+
+       reiser4_fq_put_nolock(fq);
+       reiser4_atom_send_event(atom);
+
+       spin_unlock(&(fq->guard));
+       spin_unlock_atom(atom);
+}
+
+/* A part of atom object initialization related to the embedded flush queue
+   list head */
+
+void init_atom_fq_parts(txn_atom *atom)
+{
+       INIT_LIST_HEAD(&atom->flush_queues);
+}
+
+#if REISER4_DEBUG
+
+void reiser4_check_fq(const txn_atom *atom)
+{
+       /* check number of nodes on all atom's flush queues */
+       flush_queue_t *fq;
+       int count;
+       struct list_head *pos;
+
+       count = 0;
+       list_for_each_entry(fq, &atom->flush_queues, alink) {
+               spin_lock(&(fq->guard));
+               /* calculate number of jnodes on fq' list of prepped jnodes */
+               list_for_each(pos, ATOM_FQ_LIST(fq))
+                       count++;
+               spin_unlock(&(fq->guard));
+       }
+       if (count != atom->fq)
+               warning("", "fq counter %d, real %d\n", atom->fq, count);
+
+}
+
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/forward.h linux-2.6.20/fs/reiser4/forward.h
--- linux-2.6.20.orig/fs/reiser4/forward.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/forward.h   2007-05-06 14:50:43.718981974 +0400
@@ -0,0 +1,256 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Forward declarations. Thank you Kernighan. */
+
+#if !defined( __REISER4_FORWARD_H__ )
+#define __REISER4_FORWARD_H__
+
+#include <asm/errno.h>
+#include <linux/types.h>
+
+typedef struct zlock zlock;
+typedef struct lock_stack lock_stack;
+typedef struct lock_handle lock_handle;
+typedef struct znode znode;
+typedef struct flow flow_t;
+typedef struct coord coord_t;
+typedef struct tree_access_pointer tap_t;
+typedef struct item_coord item_coord;
+typedef struct shift_params shift_params;
+typedef struct reiser4_object_create_data reiser4_object_create_data;
+typedef union reiser4_plugin reiser4_plugin;
+typedef __u16 reiser4_plugin_id;
+typedef __u64 reiser4_plugin_groups;
+typedef struct item_plugin item_plugin;
+typedef struct jnode_plugin jnode_plugin;
+typedef struct reiser4_item_data reiser4_item_data;
+typedef union reiser4_key reiser4_key;
+typedef struct reiser4_tree reiser4_tree;
+typedef struct carry_cut_data carry_cut_data;
+typedef struct carry_kill_data carry_kill_data;
+typedef struct carry_tree_op carry_tree_op;
+typedef struct carry_tree_node carry_tree_node;
+typedef struct carry_plugin_info carry_plugin_info;
+typedef struct reiser4_journal reiser4_journal;
+typedef struct txn_atom txn_atom;
+typedef struct txn_handle txn_handle;
+typedef struct txn_mgr txn_mgr;
+typedef struct reiser4_dir_entry_desc reiser4_dir_entry_desc;
+typedef struct reiser4_context reiser4_context;
+typedef struct carry_level carry_level;
+typedef struct blocknr_set_entry blocknr_set_entry;
+/* super_block->s_fs_info points to this */
+typedef struct reiser4_super_info_data reiser4_super_info_data;
+/* next two objects are fields of reiser4_super_info_data */
+typedef struct reiser4_oid_allocator reiser4_oid_allocator;
+typedef struct reiser4_space_allocator reiser4_space_allocator;
+
+typedef struct flush_scan flush_scan;
+typedef struct flush_position flush_pos_t;
+
+typedef unsigned short pos_in_node_t;
+#define MAX_POS_IN_NODE 65535
+
+typedef struct jnode jnode;
+typedef struct reiser4_blocknr_hint reiser4_blocknr_hint;
+
+typedef struct uf_coord uf_coord_t;
+typedef struct hint hint_t;
+
+typedef struct ktxnmgrd_context ktxnmgrd_context;
+
+typedef struct reiser4_xattr_plugin reiser4_xattr_plugin;
+
+struct inode;
+struct page;
+struct file;
+struct dentry;
+struct super_block;
+
+/* return values of coord_by_key(). cbk == coord_by_key */
+typedef enum {
+       CBK_COORD_FOUND = 0,
+       CBK_COORD_NOTFOUND = -ENOENT,
+} lookup_result;
+
+/* results of lookup with directory file */
+typedef enum {
+       FILE_NAME_FOUND = 0,
+       FILE_NAME_NOTFOUND = -ENOENT,
+       FILE_IO_ERROR = -EIO,   /* FIXME: it seems silly to have special OOM, IO_ERROR return codes for each search. */
+       FILE_OOM = -ENOMEM      /* FIXME: it seems silly to have special OOM, IO_ERROR return codes for each search. */
+} file_lookup_result;
+
+/* behaviors of lookup. If coord we are looking for is actually in a tree,
+    both coincide. */
+typedef enum {
+       /* search exactly for the coord with key given */
+       FIND_EXACT,
+       /* search for coord with the maximal key not greater than one
+          given */
+       FIND_MAX_NOT_MORE_THAN  /*LEFT_SLANT_BIAS */
+} lookup_bias;
+
+typedef enum {
+       /* number of leaf level of the tree
+          The fake root has (tree_level=0). */
+       LEAF_LEVEL = 1,
+
+       /* number of level one above leaf level of the tree.
+
+          It is supposed that internal tree used by reiser4 to store file
+          system data and meta data will have height 2 initially (when
+          created by mkfs).
+        */
+       TWIG_LEVEL = 2,
+} tree_level;
+
+/* The "real" maximum ztree height is the 0-origin size of any per-level
+   array, since the zero'th level is not used. */
+#define REAL_MAX_ZTREE_HEIGHT     (REISER4_MAX_ZTREE_HEIGHT-LEAF_LEVEL)
+
+/* enumeration of possible mutual position of item and coord.  This enum is
+    return type of ->is_in_item() item plugin method which see. */
+typedef enum {
+       /* coord is on the left of an item */
+       IP_ON_THE_LEFT,
+       /* coord is inside item */
+       IP_INSIDE,
+       /* coord is inside item, but to the right of the rightmost unit of
+          this item */
+       IP_RIGHT_EDGE,
+       /* coord is on the right of an item */
+       IP_ON_THE_RIGHT
+} interposition;
+
+/* type of lock to acquire on znode before returning it to caller */
+typedef enum {
+       ZNODE_NO_LOCK = 0,
+       ZNODE_READ_LOCK = 1,
+       ZNODE_WRITE_LOCK = 2,
+} znode_lock_mode;
+
+/* type of lock request */
+typedef enum {
+       ZNODE_LOCK_LOPRI = 0,
+       ZNODE_LOCK_HIPRI = (1 << 0),
+
+       /* By setting the ZNODE_LOCK_NONBLOCK flag in a lock request the call to longterm_lock_znode will not sleep
+          waiting for the lock to become available.  If the lock is unavailable, reiser4_znode_lock will immediately
+          return the value -E_REPEAT. */
+       ZNODE_LOCK_NONBLOCK = (1 << 1),
+       /* An option for longterm_lock_znode which prevents atom fusion */
+       ZNODE_LOCK_DONT_FUSE = (1 << 2)
+} znode_lock_request;
+
+typedef enum { READ_OP = 0, WRITE_OP = 1 } rw_op;
+
+/* used to specify direction of shift. These must be -1 and 1 */
+typedef enum {
+       SHIFT_LEFT = 1,
+       SHIFT_RIGHT = -1
+} shift_direction;
+
+typedef enum {
+       LEFT_SIDE,
+       RIGHT_SIDE
+} sideof;
+
+#define round_up( value, order )                                               \
+       ( ( typeof( value ) )( ( ( long ) ( value ) + ( order ) - 1U ) &        \
+                            ~( ( order ) - 1 ) ) )
+
+/* values returned by squalloc_right_neighbor and its auxiliary functions */
+typedef enum {
+       /* unit of internal item is moved */
+       SUBTREE_MOVED = 0,
+       /* nothing else can be squeezed into left neighbor */
+       SQUEEZE_TARGET_FULL = 1,
+       /* all content of node is squeezed into its left neighbor */
+       SQUEEZE_SOURCE_EMPTY = 2,
+       /* one more item is copied (this is only returned by
+          allocate_and_copy_extent to squalloc_twig)) */
+       SQUEEZE_CONTINUE = 3
+} squeeze_result;
+
+/* Do not change items ids. If you do - there will be format change */
+typedef enum {
+       STATIC_STAT_DATA_ID = 0x0,
+       SIMPLE_DIR_ENTRY_ID = 0x1,
+       COMPOUND_DIR_ID = 0x2,
+       NODE_POINTER_ID = 0x3,
+       EXTENT_POINTER_ID = 0x5,
+       FORMATTING_ID = 0x6,
+       CTAIL_ID = 0x7,
+       BLACK_BOX_ID = 0x8,
+       LAST_ITEM_ID = 0x9
+} item_id;
+
+/* Flags passed to jnode_flush() to allow it to distinguish default settings based on
+   whether commit() was called or VM memory pressure was applied. */
+typedef enum {
+       /* submit flush queue to disk at jnode_flush completion */
+       JNODE_FLUSH_WRITE_BLOCKS = 1,
+
+       /* flush is called for commit */
+       JNODE_FLUSH_COMMIT = 2,
+       /* not implemented */
+       JNODE_FLUSH_MEMORY_FORMATTED = 4,
+
+       /* not implemented */
+       JNODE_FLUSH_MEMORY_UNFORMATTED = 8,
+} jnode_flush_flags;
+
+/* Flags to insert/paste carry operations. Currently they only used in
+   flushing code, but in future, they can be used to optimize for repetitive
+   accesses.  */
+typedef enum {
+       /* carry is not allowed to shift data to the left when trying to find
+          free space  */
+       COPI_DONT_SHIFT_LEFT = (1 << 0),
+       /* carry is not allowed to shift data to the right when trying to find
+          free space  */
+       COPI_DONT_SHIFT_RIGHT = (1 << 1),
+       /* carry is not allowed to allocate new node(s) when trying to find
+          free space */
+       COPI_DONT_ALLOCATE = (1 << 2),
+       /* try to load left neighbor if its not in a cache */
+       COPI_LOAD_LEFT = (1 << 3),
+       /* try to load right neighbor if its not in a cache */
+       COPI_LOAD_RIGHT = (1 << 4),
+       /* shift insertion point to the left neighbor */
+       COPI_GO_LEFT = (1 << 5),
+       /* shift insertion point to the right neighbor */
+       COPI_GO_RIGHT = (1 << 6),
+       /* try to step back into original node if insertion into new node
+          fails after shifting data there. */
+       COPI_STEP_BACK = (1 << 7)
+} cop_insert_flag;
+
+typedef enum {
+       SAFE_UNLINK,            /* safe-link for unlink */
+       SAFE_TRUNCATE           /* safe-link for truncate */
+} reiser4_safe_link_t;
+
+/* this is to show on which list of atom jnode is */
+typedef enum {
+       NOT_CAPTURED,
+       DIRTY_LIST,
+       CLEAN_LIST,
+       FQ_LIST,
+       WB_LIST,
+       OVRWR_LIST
+} atom_list;
+
+/* __REISER4_FORWARD_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/fsdata.c linux-2.6.20/fs/reiser4/fsdata.c
--- linux-2.6.20.orig/fs/reiser4/fsdata.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/fsdata.c    2007-05-06 14:50:43.722983224 +0400
@@ -0,0 +1,803 @@
+/* Copyright 2001, 2002, 2003, 2004, 2005 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "fsdata.h"
+#include "inode.h"
+
+/* cache or dir_cursors */
+static struct kmem_cache *d_cursor_cache;
+static struct shrinker *d_cursor_shrinker;
+
+/* list of unused cursors */
+static LIST_HEAD(cursor_cache);
+
+/* number of cursors in list of ununsed cursors */
+static unsigned long d_cursor_unused = 0;
+
+/* spinlock protecting manipulations with dir_cursor's hash table and lists */
+DEFINE_SPINLOCK(d_lock);
+
+static reiser4_file_fsdata *create_fsdata(struct file *file);
+static int file_is_stateless(struct file *file);
+static void free_fsdata(reiser4_file_fsdata *fsdata);
+static void kill_cursor(dir_cursor *);
+
+/**
+ * d_cursor_shrink - shrink callback for cache of dir_cursor-s
+ * @nr: number of objects to free
+ * @mask: GFP mask
+ *
+ * Shrinks d_cursor_cache. Scan LRU list of unused cursors, freeing requested
+ * number. Return number of still freeable cursors.
+ */
+static int d_cursor_shrink(int nr, gfp_t mask)
+{
+       if (nr != 0) {
+               dir_cursor *scan;
+               int killed;
+
+               killed = 0;
+               spin_lock(&d_lock);
+               while (!list_empty(&cursor_cache)) {
+                       scan = list_entry(cursor_cache.next, dir_cursor, alist);
+                       assert("nikita-3567", scan->ref == 0);
+                       kill_cursor(scan);
+                       ++killed;
+                       --nr;
+                       if (nr == 0)
+                               break;
+               }
+               spin_unlock(&d_lock);
+       }
+       return d_cursor_unused;
+}
+
+/**
+ * reiser4_init_d_cursor - create d_cursor cache
+ *
+ * Initializes slab cache of d_cursors. It is part of reiser4 module
+ * initialization.
+ */
+int reiser4_init_d_cursor(void)
+{
+       d_cursor_cache = kmem_cache_create("d_cursor", sizeof(dir_cursor), 0,
+                                          SLAB_HWCACHE_ALIGN, NULL, NULL);
+       if (d_cursor_cache == NULL)
+               return RETERR(-ENOMEM);
+
+       /*
+        * actually, d_cursors are "priceless", because there is no way to
+        * recover information stored in them. On the other hand, we don't
+        * want to consume all kernel memory by them. As a compromise, just
+        * assign higher "seeks" value to d_cursor cache, so that it will be
+        * shrunk only if system is really tight on memory.
+        */
+       d_cursor_shrinker = set_shrinker(DEFAULT_SEEKS << 3,
+                                        d_cursor_shrink);
+       if (d_cursor_shrinker == NULL) {
+               destroy_reiser4_cache(&d_cursor_cache);
+               d_cursor_cache = NULL;
+               return RETERR(-ENOMEM);
+       }
+       return 0;
+}
+
+/**
+ * reiser4_done_d_cursor - delete d_cursor cache and d_cursor shrinker
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void reiser4_done_d_cursor(void)
+{
+       BUG_ON(d_cursor_shrinker == NULL);
+       remove_shrinker(d_cursor_shrinker);
+       d_cursor_shrinker = NULL;
+
+       destroy_reiser4_cache(&d_cursor_cache);
+}
+
+#define D_CURSOR_TABLE_SIZE (256)
+
+static inline unsigned long
+d_cursor_hash(d_cursor_hash_table *table, const d_cursor_key *key)
+{
+       assert("nikita-3555", IS_POW(D_CURSOR_TABLE_SIZE));
+       return (key->oid + key->cid) & (D_CURSOR_TABLE_SIZE - 1);
+}
+
+static inline int d_cursor_eq(const d_cursor_key *k1, const d_cursor_key *k2)
+{
+       return k1->cid == k2->cid && k1->oid == k2->oid;
+}
+
+/*
+ * define functions to manipulate reiser4 super block's hash table of
+ * dir_cursors
+ */
+#define KMALLOC(size) kmalloc((size), reiser4_ctx_gfp_mask_get())
+#define KFREE(ptr, size) kfree(ptr)
+TYPE_SAFE_HASH_DEFINE(d_cursor,
+                     dir_cursor,
+                     d_cursor_key, key, hash, d_cursor_hash, d_cursor_eq);
+#undef KFREE
+#undef KMALLOC
+
+/**
+ * reiser4_init_super_d_info - initialize per-super-block d_cursor resources
+ * @super: super block to initialize
+ *
+ * Initializes per-super-block d_cursor's hash table and radix tree. It is part
+ * of mount.
+ */
+int reiser4_init_super_d_info(struct super_block *super)
+{
+       d_cursor_info *p;
+
+       p = &get_super_private(super)->d_info;
+
+       INIT_RADIX_TREE(&p->tree, reiser4_ctx_gfp_mask_get());
+       return d_cursor_hash_init(&p->table, D_CURSOR_TABLE_SIZE);
+}
+
+/**
+ * reiser4_done_super_d_info - release per-super-block d_cursor resources
+ * @super: super block being umounted
+ *
+ * It is called on umount. Kills all directory cursors attached to suoer block.
+ */
+void reiser4_done_super_d_info(struct super_block *super)
+{
+       d_cursor_info *d_info;
+       dir_cursor *cursor, *next;
+
+       d_info = &get_super_private(super)->d_info;
+       for_all_in_htable(&d_info->table, d_cursor, cursor, next)
+               kill_cursor(cursor);
+
+       BUG_ON(d_info->tree.rnode != NULL);
+       d_cursor_hash_done(&d_info->table);
+}
+
+/**
+ * kill_cursor - free dir_cursor and reiser4_file_fsdata attached to it
+ * @cursor: cursor to free
+ *
+ * Removes reiser4_file_fsdata attached to @cursor from readdir list of
+ * reiser4_inode, frees that reiser4_file_fsdata. Removes @cursor from from
+ * indices, hash table, list of unused cursors and frees it.
+ */
+static void kill_cursor(dir_cursor *cursor)
+{
+       unsigned long index;
+
+       assert("nikita-3566", cursor->ref == 0);
+       assert("nikita-3572", cursor->fsdata != NULL);
+
+       index = (unsigned long)cursor->key.oid;
+       list_del_init(&cursor->fsdata->dir.linkage);
+       free_fsdata(cursor->fsdata);
+       cursor->fsdata = NULL;
+
+       if (list_empty_careful(&cursor->list))
+               /* this is last cursor for a file. Kill radix-tree entry */
+               radix_tree_delete(&cursor->info->tree, index);
+       else {
+               void **slot;
+
+               /*
+                * there are other cursors for the same oid.
+                */
+
+               /*
+                * if radix tree point to the cursor being removed, re-target
+                * radix tree slot to the next cursor in the (non-empty as was
+                * checked above) element of the circular list of all cursors
+                * for this oid.
+                */
+               slot = radix_tree_lookup_slot(&cursor->info->tree, index);
+               assert("nikita-3571", *slot != NULL);
+               if (*slot == cursor)
+                       *slot = list_entry(cursor->list.next, dir_cursor, list);
+               /* remove cursor from circular list */
+               list_del_init(&cursor->list);
+       }
+       /* remove cursor from the list of unused cursors */
+       list_del_init(&cursor->alist);
+       /* remove cursor from the hash table */
+       d_cursor_hash_remove(&cursor->info->table, cursor);
+       /* and free it */
+       kmem_cache_free(d_cursor_cache, cursor);
+       --d_cursor_unused;
+}
+
+/* possible actions that can be performed on all cursors for the given file */
+enum cursor_action {
+       /*
+        * load all detached state: this is called when stat-data is loaded
+        * from the disk to recover information about all pending readdirs
+        */
+       CURSOR_LOAD,
+       /*
+        * detach all state from inode, leaving it in the cache. This is called
+        * when inode is removed form the memory by memory pressure
+        */
+       CURSOR_DISPOSE,
+       /*
+        * detach cursors from the inode, and free them. This is called when
+        * inode is destroyed
+        */
+       CURSOR_KILL
+};
+
+/*
+ * return d_cursor data for the file system @inode is in.
+ */
+static inline d_cursor_info *d_info(struct inode *inode)
+{
+       return &get_super_private(inode->i_sb)->d_info;
+}
+
+/*
+ * lookup d_cursor in the per-super-block radix tree.
+ */
+static inline dir_cursor *lookup(d_cursor_info * info, unsigned long index)
+{
+       return (dir_cursor *) radix_tree_lookup(&info->tree, index);
+}
+
+/*
+ * attach @cursor to the radix tree. There may be multiple cursors for the
+ * same oid, they are chained into circular list.
+ */
+static void bind_cursor(dir_cursor * cursor, unsigned long index)
+{
+       dir_cursor *head;
+
+       head = lookup(cursor->info, index);
+       if (head == NULL) {
+               /* this is the first cursor for this index */
+               INIT_LIST_HEAD(&cursor->list);
+               radix_tree_insert(&cursor->info->tree, index, cursor);
+       } else {
+               /* some cursor already exists. Chain ours */
+               list_add(&cursor->list, &head->list);
+       }
+}
+
+/*
+ * detach fsdata (if detachable) from file descriptor, and put cursor on the
+ * "unused" list. Called when file descriptor is not longer in active use.
+ */
+static void clean_fsdata(struct file *file)
+{
+       dir_cursor *cursor;
+       reiser4_file_fsdata *fsdata;
+
+       assert("nikita-3570", file_is_stateless(file));
+
+       fsdata = (reiser4_file_fsdata *) file->private_data;
+       if (fsdata != NULL) {
+               cursor = fsdata->cursor;
+               if (cursor != NULL) {
+                       spin_lock(&d_lock);
+                       --cursor->ref;
+                       if (cursor->ref == 0) {
+                               list_add_tail(&cursor->alist, &cursor_cache);
+                               ++d_cursor_unused;
+                       }
+                       spin_unlock(&d_lock);
+                       file->private_data = NULL;
+               }
+       }
+}
+
+/*
+ * global counter used to generate "client ids". These ids are encoded into
+ * high bits of fpos.
+ */
+static __u32 cid_counter = 0;
+#define CID_SHIFT (20)
+#define CID_MASK  (0xfffffull)
+
+static void free_file_fsdata_nolock(struct file *);
+
+/**
+ * insert_cursor - allocate file_fsdata, insert cursor to tree and hash table
+ * @cursor:
+ * @file:
+ * @inode:
+ *
+ * Allocates reiser4_file_fsdata, attaches it to @cursor, inserts cursor to
+ * reiser4 super block's hash table and radix tree.
+ add detachable readdir
+ * state to the @f
+ */
+static int insert_cursor(dir_cursor *cursor, struct file *file,
+                        struct inode *inode)
+{
+       int result;
+       reiser4_file_fsdata *fsdata;
+
+       memset(cursor, 0, sizeof *cursor);
+
+       /* this is either first call to readdir, or rewind. Anyway, create new
+        * cursor. */
+       fsdata = create_fsdata(NULL);
+       if (fsdata != NULL) {
+               result = radix_tree_preload(reiser4_ctx_gfp_mask_get());
+               if (result == 0) {
+                       d_cursor_info *info;
+                       oid_t oid;
+
+                       info = d_info(inode);
+                       oid = get_inode_oid(inode);
+                       /* cid occupies higher 12 bits of f->f_pos. Don't
+                        * allow it to become negative: this confuses
+                        * nfsd_readdir() */
+                       cursor->key.cid = (++cid_counter) & 0x7ff;
+                       cursor->key.oid = oid;
+                       cursor->fsdata = fsdata;
+                       cursor->info = info;
+                       cursor->ref = 1;
+
+                       spin_lock_inode(inode);
+                       /* install cursor as @f's private_data, discarding old
+                        * one if necessary */
+#if REISER4_DEBUG
+                       if (file->private_data)
+                               warning("", "file has fsdata already");
+#endif
+                       clean_fsdata(file);
+                       free_file_fsdata_nolock(file);
+                       file->private_data = fsdata;
+                       fsdata->cursor = cursor;
+                       spin_unlock_inode(inode);
+                       spin_lock(&d_lock);
+                       /* insert cursor into hash table */
+                       d_cursor_hash_insert(&info->table, cursor);
+                       /* and chain it into radix-tree */
+                       bind_cursor(cursor, (unsigned long)oid);
+                       spin_unlock(&d_lock);
+                       radix_tree_preload_end();
+                       file->f_pos = ((__u64) cursor->key.cid) << CID_SHIFT;
+               }
+       } else
+               result = RETERR(-ENOMEM);
+       return result;
+}
+
+/**
+ * process_cursors - do action on each cursor attached to inode
+ * @inode:
+ * @act: action to do
+ *
+ * Finds all cursors of @inode in reiser4's super block radix tree of cursors
+ * and performs action specified by @act on each of cursors.
+ */
+static void process_cursors(struct inode *inode, enum cursor_action act)
+{
+       oid_t oid;
+       dir_cursor *start;
+       struct list_head *head;
+       reiser4_context *ctx;
+       d_cursor_info *info;
+
+       /* this can be called by
+        *
+        * kswapd->...->prune_icache->..reiser4_destroy_inode
+        *
+        * without reiser4_context
+        */
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx)) {
+               warning("vs-23", "failed to init context");
+               return;
+       }
+
+       assert("nikita-3558", inode != NULL);
+
+       info = d_info(inode);
+       oid = get_inode_oid(inode);
+       spin_lock_inode(inode);
+       head = get_readdir_list(inode);
+       spin_lock(&d_lock);
+       /* find any cursor for this oid: reference to it is hanging of radix
+        * tree */
+       start = lookup(info, (unsigned long)oid);
+       if (start != NULL) {
+               dir_cursor *scan;
+               reiser4_file_fsdata *fsdata;
+
+               /* process circular list of cursors for this oid */
+               scan = start;
+               do {
+                       dir_cursor *next;
+
+                       next = list_entry(scan->list.next, dir_cursor, list);
+                       fsdata = scan->fsdata;
+                       assert("nikita-3557", fsdata != NULL);
+                       if (scan->key.oid == oid) {
+                               switch (act) {
+                               case CURSOR_DISPOSE:
+                                       list_del_init(&fsdata->dir.linkage);
+                                       break;
+                               case CURSOR_LOAD:
+                                       list_add(&fsdata->dir.linkage, head);
+                                       break;
+                               case CURSOR_KILL:
+                                       kill_cursor(scan);
+                                       break;
+                               }
+                       }
+                       if (scan == next)
+                               /* last cursor was just killed */
+                               break;
+                       scan = next;
+               } while (scan != start);
+       }
+       spin_unlock(&d_lock);
+       /* check that we killed 'em all */
+       assert("nikita-3568",
+              ergo(act == CURSOR_KILL,
+                   list_empty_careful(get_readdir_list(inode))));
+       assert("nikita-3569",
+              ergo(act == CURSOR_KILL, lookup(info, oid) == NULL));
+       spin_unlock_inode(inode);
+       reiser4_exit_context(ctx);
+}
+
+/**
+ * reiser4_dispose_cursors - removes cursors from inode's list
+ * @inode: inode to dispose cursors of
+ *
+ * For each of cursors corresponding to @inode - removes reiser4_file_fsdata
+ * attached to cursor from inode's readdir list. This is called when inode is
+ * removed from the memory by memory pressure.
+ */
+void reiser4_dispose_cursors(struct inode *inode)
+{
+       process_cursors(inode, CURSOR_DISPOSE);
+}
+
+/**
+ * reiser4_load_cursors - attach cursors to inode
+ * @inode: inode to load cursors to
+ *
+ * For each of cursors corresponding to @inode - attaches reiser4_file_fsdata
+ * attached to cursor to inode's readdir list. This is done when inode is
+ * loaded into memory.
+ */
+void reiser4_load_cursors(struct inode *inode)
+{
+       process_cursors(inode, CURSOR_LOAD);
+}
+
+/**
+ * reiser4_kill_cursors - kill all inode cursors
+ * @inode: inode to kill cursors of
+ *
+ * Frees all cursors for this inode. This is called when inode is destroyed.
+ */
+void reiser4_kill_cursors(struct inode *inode)
+{
+       process_cursors(inode, CURSOR_KILL);
+}
+
+/**
+ * file_is_stateless -
+ * @file:
+ *
+ * true, if file descriptor @f is created by NFS server by "demand" to serve
+ * one file system operation. This means that there may be "detached state"
+ * for underlying inode.
+ */
+static int file_is_stateless(struct file *file)
+{
+       return reiser4_get_dentry_fsdata(file->f_dentry)->stateless;
+}
+
+/**
+ * reiser4_get_dir_fpos -
+ * @dir:
+ *
+ * Calculates ->fpos from user-supplied cookie. Normally it is dir->f_pos, but
+ * in the case of stateless directory operation (readdir-over-nfs), client id
+ * was encoded in the high bits of cookie and should me masked off.
+ */
+loff_t reiser4_get_dir_fpos(struct file *dir)
+{
+       if (file_is_stateless(dir))
+               return dir->f_pos & CID_MASK;
+       else
+               return dir->f_pos;
+}
+
+/**
+ * reiser4_attach_fsdata - try to attach fsdata
+ * @file:
+ * @inode:
+ *
+ * Finds or creates cursor for readdir-over-nfs.
+ */
+int reiser4_attach_fsdata(struct file *file, struct inode *inode)
+{
+       loff_t pos;
+       int result;
+       dir_cursor *cursor;
+
+       /*
+        * we are serialized by inode->i_mutex
+        */
+       if (!file_is_stateless(file))
+               return 0;
+
+       pos = file->f_pos;
+       result = 0;
+       if (pos == 0) {
+               /*
+                * first call to readdir (or rewind to the beginning of
+                * directory)
+                */
+               cursor = kmem_cache_alloc(d_cursor_cache,
+                                         reiser4_ctx_gfp_mask_get());
+               if (cursor != NULL)
+                       result = insert_cursor(cursor, file, inode);
+               else
+                       result = RETERR(-ENOMEM);
+       } else {
+               /* try to find existing cursor */
+               d_cursor_key key;
+
+               key.cid = pos >> CID_SHIFT;
+               key.oid = get_inode_oid(inode);
+               spin_lock(&d_lock);
+               cursor = d_cursor_hash_find(&d_info(inode)->table, &key);
+               if (cursor != NULL) {
+                       /* cursor was found */
+                       if (cursor->ref == 0) {
+                               /* move it from unused list */
+                               list_del_init(&cursor->alist);
+                               --d_cursor_unused;
+                       }
+                       ++cursor->ref;
+               }
+               spin_unlock(&d_lock);
+               if (cursor != NULL) {
+                       spin_lock_inode(inode);
+                       assert("nikita-3556", cursor->fsdata->back == NULL);
+                       clean_fsdata(file);
+                       free_file_fsdata_nolock(file);
+                       file->private_data = cursor->fsdata;
+                       spin_unlock_inode(inode);
+               }
+       }
+       return result;
+}
+
+/**
+ * reiser4_detach_fsdata - ???
+ * @file:
+ *
+ * detach fsdata, if necessary
+ */
+void reiser4_detach_fsdata(struct file *file)
+{
+       struct inode *inode;
+
+       if (!file_is_stateless(file))
+               return;
+
+       inode = file->f_dentry->d_inode;
+       spin_lock_inode(inode);
+       clean_fsdata(file);
+       spin_unlock_inode(inode);
+}
+
+/* slab for reiser4_dentry_fsdata */
+static struct kmem_cache *dentry_fsdata_cache;
+
+/**
+ * reiser4_init_dentry_fsdata - create cache of dentry_fsdata
+ *
+ * Initializes slab cache of structures attached to denty->d_fsdata. It is
+ * part of reiser4 module initialization.
+ */
+int reiser4_init_dentry_fsdata(void)
+{
+       dentry_fsdata_cache = kmem_cache_create("dentry_fsdata",
+                                               sizeof(reiser4_dentry_fsdata),
+                                               0,
+                                               SLAB_HWCACHE_ALIGN |
+                                               SLAB_RECLAIM_ACCOUNT, NULL,
+                                               NULL);
+       if (dentry_fsdata_cache == NULL)
+               return RETERR(-ENOMEM);
+       return 0;
+}
+
+/**
+ * reiser4_done_dentry_fsdata - delete cache of dentry_fsdata
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void reiser4_done_dentry_fsdata(void)
+{
+       destroy_reiser4_cache(&dentry_fsdata_cache);
+}
+
+/**
+ * reiser4_get_dentry_fsdata - get fs-specific dentry data
+ * @dentry: queried dentry
+ *
+ * Allocates if necessary and returns per-dentry data that we attach to each
+ * dentry.
+ */
+reiser4_dentry_fsdata *reiser4_get_dentry_fsdata(struct dentry *dentry)
+{
+       assert("nikita-1365", dentry != NULL);
+
+       if (dentry->d_fsdata == NULL) {
+               dentry->d_fsdata = kmem_cache_alloc(dentry_fsdata_cache,
+                                                   reiser4_ctx_gfp_mask_get());
+               if (dentry->d_fsdata == NULL)
+                       return ERR_PTR(RETERR(-ENOMEM));
+               memset(dentry->d_fsdata, 0, sizeof(reiser4_dentry_fsdata));
+       }
+       return dentry->d_fsdata;
+}
+
+/**
+ * reiser4_free_dentry_fsdata - detach and free dentry_fsdata
+ * @dentry: dentry to free fsdata of
+ *
+ * Detaches and frees fs-specific dentry data
+ */
+void reiser4_free_dentry_fsdata(struct dentry *dentry)
+{
+       if (dentry->d_fsdata != NULL) {
+               kmem_cache_free(dentry_fsdata_cache, dentry->d_fsdata);
+               dentry->d_fsdata = NULL;
+       }
+}
+
+/* slab for reiser4_file_fsdata */
+static struct kmem_cache *file_fsdata_cache;
+
+/**
+ * reiser4_init_file_fsdata - create cache of reiser4_file_fsdata
+ *
+ * Initializes slab cache of structures attached to file->private_data. It is
+ * part of reiser4 module initialization.
+ */
+int reiser4_init_file_fsdata(void)
+{
+       file_fsdata_cache = kmem_cache_create("file_fsdata",
+                                             sizeof(reiser4_file_fsdata),
+                                             0,
+                                             SLAB_HWCACHE_ALIGN |
+                                             SLAB_RECLAIM_ACCOUNT, NULL, NULL);
+       if (file_fsdata_cache == NULL)
+               return RETERR(-ENOMEM);
+       return 0;
+}
+
+/**
+ * reiser4_done_file_fsdata - delete cache of reiser4_file_fsdata
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void reiser4_done_file_fsdata(void)
+{
+       destroy_reiser4_cache(&file_fsdata_cache);
+}
+
+/**
+ * create_fsdata - allocate and initialize reiser4_file_fsdata
+ * @file: what to create file_fsdata for, may be NULL
+ *
+ * Allocates and initializes reiser4_file_fsdata structure.
+ */
+static reiser4_file_fsdata *create_fsdata(struct file *file)
+{
+       reiser4_file_fsdata *fsdata;
+
+       fsdata = kmem_cache_alloc(file_fsdata_cache,
+                                 reiser4_ctx_gfp_mask_get());
+       if (fsdata != NULL) {
+               memset(fsdata, 0, sizeof *fsdata);
+               fsdata->ra1.max_window_size = VM_MAX_READAHEAD * 1024;
+               fsdata->back = file;
+               INIT_LIST_HEAD(&fsdata->dir.linkage);
+       }
+       return fsdata;
+}
+
+/**
+ * free_fsdata - free reiser4_file_fsdata
+ * @fsdata: object to free
+ *
+ * Dual to create_fsdata(). Free reiser4_file_fsdata.
+ */
+static void free_fsdata(reiser4_file_fsdata *fsdata)
+{
+       BUG_ON(fsdata == NULL);
+       kmem_cache_free(file_fsdata_cache, fsdata);
+}
+
+/**
+ * reiser4_get_file_fsdata - get fs-specific file data
+ * @file: queried file
+ *
+ * Returns fs-specific data of @file. If it is NULL, allocates it and attaches
+ * to @file.
+ */
+reiser4_file_fsdata *reiser4_get_file_fsdata(struct file *file)
+{
+       assert("nikita-1603", file != NULL);
+
+       if (file->private_data == NULL) {
+               reiser4_file_fsdata *fsdata;
+               struct inode *inode;
+
+               fsdata = create_fsdata(file);
+               if (fsdata == NULL)
+                       return ERR_PTR(RETERR(-ENOMEM));
+
+               inode = file->f_dentry->d_inode;
+               spin_lock_inode(inode);
+               if (file->private_data == NULL) {
+                       file->private_data = fsdata;
+                       fsdata = NULL;
+               }
+               spin_unlock_inode(inode);
+               if (fsdata != NULL)
+                       /* other thread initialized ->fsdata */
+                       kmem_cache_free(file_fsdata_cache, fsdata);
+       }
+       assert("nikita-2665", file->private_data != NULL);
+       return file->private_data;
+}
+
+/**
+ * free_file_fsdata_nolock - detach and free reiser4_file_fsdata
+ * @file:
+ *
+ * Detaches reiser4_file_fsdata from @file, removes reiser4_file_fsdata from
+ * readdir list, frees if it is not linked to d_cursor object.
+ */
+static void free_file_fsdata_nolock(struct file *file)
+{
+       reiser4_file_fsdata *fsdata;
+
+       assert("", spin_inode_is_locked(file->f_dentry->d_inode));
+       fsdata = file->private_data;
+       if (fsdata != NULL) {
+               list_del_init(&fsdata->dir.linkage);
+               if (fsdata->cursor == NULL)
+                       free_fsdata(fsdata);
+       }
+       file->private_data = NULL;
+}
+
+/**
+ * reiser4_free_file_fsdata - detach from struct file and free reiser4_file_fsdata
+ * @file:
+ *
+ * Spinlocks inode and calls free_file_fsdata_nolock to do the work.
+ */
+void reiser4_free_file_fsdata(struct file *file)
+{
+       spin_lock_inode(file->f_dentry->d_inode);
+       free_file_fsdata_nolock(file);
+       spin_unlock_inode(file->f_dentry->d_inode);
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/fsdata.h linux-2.6.20/fs/reiser4/fsdata.h
--- linux-2.6.20.orig/fs/reiser4/fsdata.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/fsdata.h    2007-05-06 14:50:43.722983224 +0400
@@ -0,0 +1,207 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#if !defined( __REISER4_FSDATA_H__ )
+#define __REISER4_FSDATA_H__
+
+#include "debug.h"
+#include "kassign.h"
+#include "seal.h"
+#include "type_safe_hash.h"
+#include "plugin/file/file.h"
+#include "readahead.h"
+
+/*
+ * comment about reiser4_dentry_fsdata
+ *
+ *
+ */
+
+/*
+ * locking: fields of per file descriptor readdir_pos and ->f_pos are
+ * protected by ->i_mutex on inode. Under this lock following invariant
+ * holds:
+ *
+ *     file descriptor is "looking" at the entry_no-th directory entry from
+ *     the beginning of directory. This entry has key dir_entry_key and is
+ *     pos-th entry with duplicate-key sequence.
+ *
+ */
+
+/* logical position within directory */
+typedef struct {
+       /* key of directory entry (actually, part of a key sufficient to
+          identify directory entry)  */
+       de_id dir_entry_key;
+       /* ordinal number of directory entry among all entries with the same
+          key. (Starting from 0.) */
+       unsigned pos;
+} dir_pos;
+
+typedef struct {
+       /* f_pos corresponding to this readdir position */
+       __u64 fpos;
+       /* logical position within directory */
+       dir_pos position;
+       /* logical number of directory entry within
+          directory  */
+       __u64 entry_no;
+} readdir_pos;
+
+/*
+ * this is used to speed up lookups for directory entry: on initial call to
+ * ->lookup() seal and coord of directory entry (if found, that is) are stored
+ * in struct dentry and reused later to avoid tree traversals.
+ */
+typedef struct de_location {
+       /* seal covering directory entry */
+       seal_t entry_seal;
+       /* coord of directory entry */
+       coord_t entry_coord;
+       /* ordinal number of directory entry among all entries with the same
+          key. (Starting from 0.) */
+       int pos;
+} de_location;
+
+/**
+ * reiser4_dentry_fsdata - reiser4-specific data attached to dentries
+ *
+ * This is allocated dynamically and released in d_op->d_release()
+ *
+ * Currently it only contains cached location (hint) of directory entry, but
+ * it is expected that other information will be accumulated here.
+ */
+typedef struct reiser4_dentry_fsdata {
+       /*
+        * here will go fields filled by ->lookup() to speedup next
+        * create/unlink, like blocknr of znode with stat-data, or key of
+        * stat-data.
+        */
+       de_location dec;
+       int stateless;          /* created through reiser4_decode_fh, needs special
+                                * treatment in readdir. */
+} reiser4_dentry_fsdata;
+
+extern int reiser4_init_dentry_fsdata(void);
+extern void reiser4_done_dentry_fsdata(void);
+extern reiser4_dentry_fsdata *reiser4_get_dentry_fsdata(struct dentry *);
+extern void reiser4_free_dentry_fsdata(struct dentry *dentry);
+
+/**
+ * reiser4_file_fsdata - reiser4-specific data attached to file->private_data
+ *
+ * This is allocated dynamically and released in inode->i_fop->release
+ */
+typedef struct reiser4_file_fsdata {
+       /*
+        * pointer back to the struct file which this reiser4_file_fsdata is
+        * part of
+        */
+       struct file *back;
+       /* detached cursor for stateless readdir. */
+       struct dir_cursor *cursor;
+       /*
+        * We need both directory and regular file parts here, because there
+        * are file system objects that are files and directories.
+        */
+       struct {
+               /*
+                * position in directory. It is updated each time directory is
+                * modified
+                */
+               readdir_pos readdir;
+               /* head of this list is reiser4_inode->lists.readdir_list */
+               struct list_head linkage;
+       } dir;
+       /* hints to speed up operations with regular files: read and write. */
+       struct {
+               hint_t hint;
+       } reg;
+       struct reiser4_file_ra_state ra1;
+
+} reiser4_file_fsdata;
+
+extern int reiser4_init_file_fsdata(void);
+extern void reiser4_done_file_fsdata(void);
+extern reiser4_file_fsdata *reiser4_get_file_fsdata(struct file *);
+extern void reiser4_free_file_fsdata(struct file *);
+
+/*
+ * d_cursor is reiser4_file_fsdata not attached to struct file. d_cursors are
+ * used to address problem reiser4 has with readdir accesses via NFS. See
+ * plugin/file_ops_readdir.c for more details.
+ */
+typedef struct {
+       __u16 cid;
+       __u64 oid;
+} d_cursor_key;
+
+/*
+ * define structures d_cursor_hash_table d_cursor_hash_link which are used to
+ * maintain hash table of dir_cursor-s in reiser4's super block
+ */
+typedef struct dir_cursor dir_cursor;
+TYPE_SAFE_HASH_DECLARE(d_cursor, dir_cursor);
+
+typedef struct d_cursor_info d_cursor_info;
+
+struct dir_cursor {
+       int ref;
+       reiser4_file_fsdata *fsdata;
+
+       /* link to reiser4 super block hash table of cursors */
+       d_cursor_hash_link hash;
+
+       /*
+        * this is to link cursors to reiser4 super block's radix tree of
+        * cursors if there are more than one cursor of the same objectid
+        */
+       struct list_head list;
+       d_cursor_key key;
+       d_cursor_info *info;
+       /* list of unused cursors */
+       struct list_head alist;
+};
+
+extern int reiser4_init_d_cursor(void);
+extern void reiser4_done_d_cursor(void);
+
+extern int reiser4_init_super_d_info(struct super_block *);
+extern void reiser4_done_super_d_info(struct super_block *);
+
+extern loff_t reiser4_get_dir_fpos(struct file *);
+extern int reiser4_attach_fsdata(struct file *, struct inode *);
+extern void reiser4_detach_fsdata(struct file *);
+
+/* these are needed for "stateless" readdir. See plugin/file_ops_readdir.c for
+   more details */
+void reiser4_dispose_cursors(struct inode *inode);
+void reiser4_load_cursors(struct inode *inode);
+void reiser4_kill_cursors(struct inode *inode);
+void reiser4_adjust_dir_file(struct inode *dir, const struct dentry *de,
+                            int offset, int adj);
+
+/*
+ * this structure is embedded to reise4_super_info_data. It maintains d_cursors
+ * (detached readdir state). See plugin/file_ops_readdir.c for more details.
+ */
+struct d_cursor_info {
+       d_cursor_hash_table table;
+       struct radix_tree_root tree;
+};
+
+/* spinlock protecting readdir cursors */
+extern spinlock_t d_lock;
+
+/* __REISER4_FSDATA_H__ */
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/init_super.c linux-2.6.20/fs/reiser4/init_super.c
--- linux-2.6.20.orig/fs/reiser4/init_super.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/init_super.c        2007-05-06 14:50:43.722983224 +0400
@@ -0,0 +1,750 @@
+/* Copyright by Hans Reiser, 2003 */
+
+#include "super.h"
+#include "inode.h"
+#include "plugin/plugin_set.h"
+
+#include <linux/swap.h>
+
+/**
+ * init_fs_info - allocate reiser4 specific super block
+ * @super: super block of filesystem
+ *
+ * Allocates and initialize reiser4_super_info_data, attaches it to
+ * super->s_fs_info, initializes structures maintaining d_cursor-s.
+ */
+int reiser4_init_fs_info(struct super_block *super)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = kmalloc(sizeof(reiser4_super_info_data),
+                        reiser4_ctx_gfp_mask_get());
+       if (!sbinfo)
+               return RETERR(-ENOMEM);
+
+       super->s_fs_info = sbinfo;
+       super->s_op = NULL;
+       memset(sbinfo, 0, sizeof(*sbinfo));
+
+       ON_DEBUG(INIT_LIST_HEAD(&sbinfo->all_jnodes));
+       ON_DEBUG(spin_lock_init(&sbinfo->all_guard));
+
+       mutex_init(&sbinfo->delete_mutex);
+       spin_lock_init(&(sbinfo->guard));
+
+       /*  initialize per-super-block d_cursor resources */
+       reiser4_init_super_d_info(super);
+
+       return 0;
+}
+
+/**
+ * reiser4_done_fs_info - free reiser4 specific super block
+ * @super: super block of filesystem
+ *
+ * Performs some sanity checks, releases structures maintaining d_cursor-s,
+ * frees reiser4_super_info_data.
+ */
+void reiser4_done_fs_info(struct super_block *super)
+{
+       assert("zam-990", super->s_fs_info != NULL);
+
+       /* release per-super-block d_cursor resources */
+       reiser4_done_super_d_info(super);
+
+       /* make sure that there are not jnodes already */
+       assert("", list_empty(&get_super_private(super)->all_jnodes));
+       assert("", get_current_context()->trans->atom == NULL);
+       reiser4_check_block_counters(super);
+       kfree(super->s_fs_info);
+       super->s_fs_info = NULL;
+}
+
+/* type of option parseable by parse_option() */
+typedef enum {
+       /* value of option is arbitrary string */
+       OPT_STRING,
+
+       /*
+        * option specifies bit in a bitmask. When option is set - bit in
+        * sbinfo->fs_flags is set. Examples are bsdgroups, 32bittimes, mtflush,
+        * dont_load_bitmap, atomic_write.
+        */
+       OPT_BIT,
+
+       /*
+        * value of option should conform to sprintf() format. Examples are
+        * tmgr.atom_max_size=N, tmgr.atom_max_age=N
+        */
+       OPT_FORMAT,
+
+       /*
+        * option can take one of predefined values. Example is onerror=panic or
+        * onerror=remount-ro
+        */
+       OPT_ONEOF,
+} opt_type_t;
+
+typedef struct opt_bitmask_bit {
+       const char *bit_name;
+       int bit_nr;
+} opt_bitmask_bit;
+
+/* description of option parseable by parse_option() */
+typedef struct opt_desc {
+       /* option name.
+
+          parsed portion of string has a form "name=value".
+        */
+       const char *name;
+       /* type of option */
+       opt_type_t type;
+       union {
+               /* where to store value of string option (type == OPT_STRING) */
+               char **string;
+               /* description of bits for bit option (type == OPT_BIT) */
+               struct {
+                       int nr;
+                       void *addr;
+               } bit;
+               /* description of format and targets for format option (type
+                  == OPT_FORMAT) */
+               struct {
+                       const char *format;
+                       int nr_args;
+                       void *arg1;
+                       void *arg2;
+                       void *arg3;
+                       void *arg4;
+               } f;
+               struct {
+                       int *result;
+                       const char *list[10];
+               } oneof;
+               struct {
+                       void *addr;
+                       int nr_bits;
+                       opt_bitmask_bit *bits;
+               } bitmask;
+       } u;
+} opt_desc_t;
+
+/**
+ * parse_option - parse one option
+ * @opt_strin: starting point of parsing
+ * @opt: option description
+ *
+ * foo=bar,
+ * ^   ^  ^
+ * |   |  +-- replaced to '\0'
+ * |   +-- val_start
+ * +-- opt_string
+ * Figures out option type and handles option correspondingly.
+ */
+static int parse_option(char *opt_string, opt_desc_t *opt)
+{
+       char *val_start;
+       int result;
+       const char *err_msg;
+
+       /* NOTE-NIKITA think about using lib/cmdline.c functions here. */
+
+       val_start = strchr(opt_string, '=');
+       if (val_start != NULL) {
+               *val_start = '\0';
+               ++val_start;
+       }
+
+       err_msg = NULL;
+       result = 0;
+       switch (opt->type) {
+       case OPT_STRING:
+               if (val_start == NULL) {
+                       err_msg = "String arg missing";
+                       result = RETERR(-EINVAL);
+               } else
+                       *opt->u.string = val_start;
+               break;
+       case OPT_BIT:
+               if (val_start != NULL)
+                       err_msg = "Value ignored";
+               else
+                       set_bit(opt->u.bit.nr, opt->u.bit.addr);
+               break;
+       case OPT_FORMAT:
+               if (val_start == NULL) {
+                       err_msg = "Formatted arg missing";
+                       result = RETERR(-EINVAL);
+                       break;
+               }
+               if (sscanf(val_start, opt->u.f.format,
+                          opt->u.f.arg1, opt->u.f.arg2, opt->u.f.arg3,
+                          opt->u.f.arg4) != opt->u.f.nr_args) {
+                       err_msg = "Wrong conversion";
+                       result = RETERR(-EINVAL);
+               }
+               break;
+       case OPT_ONEOF:
+               {
+                       int i = 0;
+
+                       if (val_start == NULL) {
+                               err_msg = "Value is missing";
+                               result = RETERR(-EINVAL);
+                               break;
+                       }
+                       err_msg = "Wrong option value";
+                       result = RETERR(-EINVAL);
+                       while (opt->u.oneof.list[i]) {
+                               if (!strcmp(opt->u.oneof.list[i], val_start)) {
+                                       result = 0;
+                                       err_msg = NULL;
+                                       *opt->u.oneof.result = i;
+                                       break;
+                               }
+                               i++;
+                       }
+                       break;
+               }
+       default:
+               wrong_return_value("nikita-2100", "opt -> type");
+               break;
+       }
+       if (err_msg != NULL) {
+               warning("nikita-2496", "%s when parsing option \"%s%s%s\"",
+                       err_msg, opt->name, val_start ? "=" : "",
+                       val_start ? : "");
+       }
+       return result;
+}
+
+/**
+ * parse_options - parse reiser4 mount options
+ * @opt_string: starting point
+ * @opts: array of option description
+ * @nr_opts: number of elements in @opts
+ *
+ * Parses comma separated list of reiser4 mount options.
+ */
+static int parse_options(char *opt_string, opt_desc_t *opts, int nr_opts)
+{
+       int result;
+
+       result = 0;
+       while ((result == 0) && opt_string && *opt_string) {
+               int j;
+               char *next;
+
+               next = strchr(opt_string, ',');
+               if (next != NULL) {
+                       *next = '\0';
+                       ++next;
+               }
+               for (j = 0; j < nr_opts; ++j) {
+                       if (!strncmp(opt_string, opts[j].name,
+                                    strlen(opts[j].name))) {
+                               result = parse_option(opt_string, &opts[j]);
+                               break;
+                       }
+               }
+               if (j == nr_opts) {
+                       warning("nikita-2307", "Unrecognized option: \"%s\"",
+                               opt_string);
+                       /* traditionally, -EINVAL is returned on wrong mount
+                          option */
+                       result = RETERR(-EINVAL);
+               }
+               opt_string = next;
+       }
+       return result;
+}
+
+#define NUM_OPT( label, fmt, addr )                            \
+               {                                               \
+                       .name = ( label ),                      \
+                       .type = OPT_FORMAT,                     \
+                       .u = {                                  \
+                               .f = {                          \
+                                       .format  = ( fmt ),     \
+                                       .nr_args = 1,           \
+                                       .arg1 = ( addr ),       \
+                                       .arg2 = NULL,           \
+                                       .arg3 = NULL,           \
+                                       .arg4 = NULL            \
+                               }                               \
+                       }                                       \
+               }
+
+#define SB_FIELD_OPT( field, fmt ) NUM_OPT( #field, fmt, &sbinfo -> field )
+
+#define BIT_OPT(label, bitnr)                                  \
+       {                                                       \
+               .name = label,                                  \
+               .type = OPT_BIT,                                \
+               .u = {                                          \
+                       .bit = {                                \
+                               .nr = bitnr,                    \
+                               .addr = &sbinfo->fs_flags       \
+                       }                                       \
+               }                                               \
+       }
+
+#define MAX_NR_OPTIONS (30)
+
+/**
+ * reiser4_init_super_data - initialize reiser4 private super block
+ * @super: super block to initialize
+ * @opt_string: list of reiser4 mount options
+ *
+ * Sets various reiser4 parameters to default values. Parses mount options and
+ * overwrites default settings.
+ */
+int reiser4_init_super_data(struct super_block *super, char *opt_string)
+{
+       int result;
+       opt_desc_t *opts, *p;
+       reiser4_super_info_data *sbinfo = get_super_private(super);
+
+       /* initialize super, export, dentry operations */
+       sbinfo->ops.super = reiser4_super_operations;
+       sbinfo->ops.export = reiser4_export_operations;
+       sbinfo->ops.dentry = reiser4_dentry_operations;
+       super->s_op = &sbinfo->ops.super;
+       super->s_export_op = &sbinfo->ops.export;
+
+       /* initialize transaction manager parameters to default values */
+       sbinfo->tmgr.atom_max_size = totalram_pages / 4;
+       sbinfo->tmgr.atom_max_age = REISER4_ATOM_MAX_AGE / HZ;
+       sbinfo->tmgr.atom_min_size = 256;
+       sbinfo->tmgr.atom_max_flushers = ATOM_MAX_FLUSHERS;
+
+       /* initialize cbk cache parameter */
+       sbinfo->tree.cbk_cache.nr_slots = CBK_CACHE_SLOTS;
+
+       /* initialize flush parameters */
+       sbinfo->flush.relocate_threshold = FLUSH_RELOCATE_THRESHOLD;
+       sbinfo->flush.relocate_distance = FLUSH_RELOCATE_DISTANCE;
+       sbinfo->flush.written_threshold = FLUSH_WRITTEN_THRESHOLD;
+       sbinfo->flush.scan_maxnodes = FLUSH_SCAN_MAXNODES;
+
+       sbinfo->optimal_io_size = REISER4_OPTIMAL_IO_SIZE;
+
+       /* preliminary tree initializations */
+       sbinfo->tree.super = super;
+       sbinfo->tree.carry.new_node_flags = REISER4_NEW_NODE_FLAGS;
+       sbinfo->tree.carry.new_extent_flags = REISER4_NEW_EXTENT_FLAGS;
+       sbinfo->tree.carry.paste_flags = REISER4_PASTE_FLAGS;
+       sbinfo->tree.carry.insert_flags = REISER4_INSERT_FLAGS;
+       rwlock_init(&(sbinfo->tree.tree_lock));
+       spin_lock_init(&(sbinfo->tree.epoch_lock));
+
+       /* initialize default readahead params */
+       sbinfo->ra_params.max = num_physpages / 4;
+       sbinfo->ra_params.flags = 0;
+
+       /* allocate memory for structure describing reiser4 mount options */
+       opts = kmalloc(sizeof(opt_desc_t) * MAX_NR_OPTIONS,
+                      reiser4_ctx_gfp_mask_get());
+       if (opts == NULL)
+               return RETERR(-ENOMEM);
+
+       /* initialize structure describing reiser4 mount options */
+       p = opts;
+
+#if REISER4_DEBUG
+#  define OPT_ARRAY_CHECK if ((p) > (opts) + MAX_NR_OPTIONS) {         \
+               warning ("zam-1046", "opt array is overloaded"); break; \
+       }
+#else
+#   define OPT_ARRAY_CHECK noop
+#endif
+
+#define PUSH_OPT(...)                          \
+do {                                           \
+        opt_desc_t o = __VA_ARGS__;            \
+        OPT_ARRAY_CHECK;                       \
+        *p ++ = o;                             \
+} while (0)
+
+#define PUSH_SB_FIELD_OPT(field, format) PUSH_OPT(SB_FIELD_OPT(field, format))
+#define PUSH_BIT_OPT(name, bit) PUSH_OPT(BIT_OPT(name, bit))
+
+       /*
+        * tmgr.atom_max_size=N
+        * Atoms containing more than N blocks will be forced to commit. N is
+        * decimal.
+        */
+       PUSH_SB_FIELD_OPT(tmgr.atom_max_size, "%u");
+       /*
+        * tmgr.atom_max_age=N
+        * Atoms older than N seconds will be forced to commit. N is decimal.
+        */
+       PUSH_SB_FIELD_OPT(tmgr.atom_max_age, "%u");
+       /*
+        * tmgr.atom_min_size=N
+        * In committing an atom to free dirty pages, force the atom less than
+        * N in size to fuse with another one.
+        */
+       PUSH_SB_FIELD_OPT(tmgr.atom_min_size, "%u");
+       /*
+        * tmgr.atom_max_flushers=N
+        * limit of concurrent flushers for one atom. 0 means no limit.
+        */
+       PUSH_SB_FIELD_OPT(tmgr.atom_max_flushers, "%u");
+       /*
+        * tree.cbk_cache_slots=N
+        * Number of slots in the cbk cache.
+        */
+       PUSH_SB_FIELD_OPT(tree.cbk_cache.nr_slots, "%u");
+       /*
+        * If flush finds more than FLUSH_RELOCATE_THRESHOLD adjacent dirty
+        * leaf-level blocks it will force them to be relocated.
+        */
+       PUSH_SB_FIELD_OPT(flush.relocate_threshold, "%u");
+       /*
+        * If flush finds can find a block allocation closer than at most
+        * FLUSH_RELOCATE_DISTANCE from the preceder it will relocate to that
+        * position.
+        */
+       PUSH_SB_FIELD_OPT(flush.relocate_distance, "%u");
+       /*
+        * If we have written this much or more blocks before encountering busy
+        * jnode in flush list - abort flushing hoping that next time we get
+        * called this jnode will be clean already, and we will save some
+        * seeks.
+        */
+       PUSH_SB_FIELD_OPT(flush.written_threshold, "%u");
+       /* The maximum number of nodes to scan left on a level during flush. */
+       PUSH_SB_FIELD_OPT(flush.scan_maxnodes, "%u");
+       /* preferred IO size */
+       PUSH_SB_FIELD_OPT(optimal_io_size, "%u");
+       /* carry flags used for insertion of new nodes */
+       PUSH_SB_FIELD_OPT(tree.carry.new_node_flags, "%u");
+       /* carry flags used for insertion of new extents */
+       PUSH_SB_FIELD_OPT(tree.carry.new_extent_flags, "%u");
+       /* carry flags used for paste operations */
+       PUSH_SB_FIELD_OPT(tree.carry.paste_flags, "%u");
+       /* carry flags used for insert operations */
+       PUSH_SB_FIELD_OPT(tree.carry.insert_flags, "%u");
+
+#ifdef CONFIG_REISER4_BADBLOCKS
+       /*
+        * Alternative master superblock location in case if it's original
+        * location is not writeable/accessable. This is offset in BYTES.
+        */
+       PUSH_SB_FIELD_OPT(altsuper, "%lu");
+#endif
+
+       /* turn on BSD-style gid assignment */
+       PUSH_BIT_OPT("bsdgroups", REISER4_BSD_GID);
+       /* turn on 32 bit times */
+       PUSH_BIT_OPT("32bittimes", REISER4_32_BIT_TIMES);
+       /*
+        * Don't load all bitmap blocks at mount time, it is useful for
+        * machines with tiny RAM and large disks.
+        */
+       PUSH_BIT_OPT("dont_load_bitmap", REISER4_DONT_LOAD_BITMAP);
+       /* disable transaction commits during write() */
+       PUSH_BIT_OPT("atomic_write", REISER4_ATOMIC_WRITE);
+       /* disable use of write barriers in the reiser4 log writer. */
+       PUSH_BIT_OPT("no_write_barrier", REISER4_NO_WRITE_BARRIER);
+
+       PUSH_OPT(
+       {
+               /*
+                * tree traversal readahead parameters:
+                * -o readahead:MAXNUM:FLAGS
+                * MAXNUM - max number fo nodes to request readahead for: -1UL
+                * will set it to max_sane_readahead()
+                * FLAGS - combination of bits: RA_ADJCENT_ONLY, RA_ALL_LEVELS,
+                * CONTINUE_ON_PRESENT
+                */
+               .name = "readahead",
+               .type = OPT_FORMAT,
+               .u = {
+                       .f = {
+                               .format = "%u:%u",
+                               .nr_args = 2,
+                               .arg1 = &sbinfo->ra_params.max,
+                               .arg2 = &sbinfo->ra_params.flags,
+                               .arg3 = NULL,
+                               .arg4 = NULL
+                       }
+               }
+       }
+       );
+
+       /* What to do in case of fs error */
+       PUSH_OPT(
+       {
+               .name = "onerror",
+               .type = OPT_ONEOF,
+               .u = {
+                       .oneof = {
+                               .result = &sbinfo->onerror,
+                               .list = {
+                                       "panic", "remount-ro", NULL
+                               },
+                       }
+               }
+       }
+       );
+
+       /* modify default settings to values set by mount options */
+       result = parse_options(opt_string, opts, p - opts);
+       kfree(opts);
+       if (result != 0)
+               return result;
+
+       /* correct settings to sanity values */
+       sbinfo->tmgr.atom_max_age *= HZ;
+       if (sbinfo->tmgr.atom_max_age <= 0)
+               /* overflow */
+               sbinfo->tmgr.atom_max_age = REISER4_ATOM_MAX_AGE;
+
+       /* round optimal io size up to 512 bytes */
+       sbinfo->optimal_io_size >>= VFS_BLKSIZE_BITS;
+       sbinfo->optimal_io_size <<= VFS_BLKSIZE_BITS;
+       if (sbinfo->optimal_io_size == 0) {
+               warning("nikita-2497", "optimal_io_size is too small");
+               return RETERR(-EINVAL);
+       }
+       return result;
+}
+
+/**
+ * reiser4_init_read_super - read reiser4 master super block
+ * @super: super block to fill
+ * @silent: if 0 - print warnings
+ *
+ * Reads reiser4 master super block either from predefined location or from
+ * location specified by altsuper mount option, initializes disk format plugin.
+ */
+int reiser4_init_read_super(struct super_block *super, int silent)
+{
+       struct buffer_head *super_bh;
+       struct reiser4_master_sb *master_sb;
+       reiser4_super_info_data *sbinfo = get_super_private(super);
+       unsigned long blocksize;
+
+ read_super_block:
+#ifdef CONFIG_REISER4_BADBLOCKS
+       if (sbinfo->altsuper)
+               /*
+                * read reiser4 master super block at position specified by
+                * mount option
+                */
+               super_bh = sb_bread(super,
+                                   (sector_t)(sbinfo->altsuper / super->s_blocksize));
+       else
+#endif
+               /* read reiser4 master super block at 16-th 4096 block */
+               super_bh = sb_bread(super,
+                                   (sector_t)(REISER4_MAGIC_OFFSET / super->s_blocksize));
+       if (!super_bh)
+               return RETERR(-EIO);
+
+       master_sb = (struct reiser4_master_sb *)super_bh->b_data;
+       /* check reiser4 magic string */
+       if (!strncmp(master_sb->magic, REISER4_SUPER_MAGIC_STRING,
+                    sizeof(REISER4_SUPER_MAGIC_STRING))) {
+               /* reiser4 master super block contains filesystem blocksize */
+               blocksize = le16_to_cpu(get_unaligned(&master_sb->blocksize));
+
+               if (blocksize != PAGE_CACHE_SIZE) {
+                       /*
+                        * currenly reiser4's blocksize must be equal to
+                        * pagesize
+                        */
+                       if (!silent)
+                               warning("nikita-2609",
+                                       "%s: wrong block size %ld\n", super->s_id,
+                                       blocksize);
+                       brelse(super_bh);
+                       return RETERR(-EINVAL);
+               }
+               if (blocksize != super->s_blocksize) {
+                       /*
+                        * filesystem uses different blocksize. Reread master
+                        * super block with correct blocksize
+                        */
+                       brelse(super_bh);
+                       if (!sb_set_blocksize(super, (int)blocksize))
+                               return RETERR(-EINVAL);
+                       goto read_super_block;
+               }
+
+               sbinfo->df_plug =
+                       disk_format_plugin_by_id(
+                               le16_to_cpu(get_unaligned(&master_sb->disk_plugin_id)));
+               if (sbinfo->df_plug == NULL) {
+                       if (!silent)
+                               warning("nikita-26091",
+                                       "%s: unknown disk format plugin %d\n",
+                                       super->s_id,
+                                       le16_to_cpu(get_unaligned(&master_sb->disk_plugin_id)));
+                       brelse(super_bh);
+                       return RETERR(-EINVAL);
+               }
+               sbinfo->diskmap_block = le64_to_cpu(get_unaligned(&master_sb->diskmap));
+               brelse(super_bh);
+               return 0;
+       }
+
+       /* there is no reiser4 on the device */
+       if (!silent)
+               warning("nikita-2608",
+                       "%s: wrong master super block magic", super->s_id);
+       brelse(super_bh);
+       return RETERR(-EINVAL);
+}
+
+static struct {
+       reiser4_plugin_type type;
+       reiser4_plugin_id id;
+} default_plugins[PSET_LAST] = {
+       [PSET_FILE] = {
+               .type = REISER4_FILE_PLUGIN_TYPE,
+               .id = UNIX_FILE_PLUGIN_ID
+       },
+       [PSET_DIR] = {
+               .type = REISER4_DIR_PLUGIN_TYPE,
+               .id = HASHED_DIR_PLUGIN_ID
+       },
+       [PSET_HASH] = {
+               .type = REISER4_HASH_PLUGIN_TYPE,
+               .id = R5_HASH_ID
+       },
+       [PSET_FIBRATION] = {
+               .type = REISER4_FIBRATION_PLUGIN_TYPE,
+               .id = FIBRATION_DOT_O
+       },
+       [PSET_PERM] = {
+               .type = REISER4_PERM_PLUGIN_TYPE,
+               .id = NULL_PERM_ID
+       },
+       [PSET_FORMATTING] = {
+               .type = REISER4_FORMATTING_PLUGIN_TYPE,
+               .id = SMALL_FILE_FORMATTING_ID
+       },
+       [PSET_SD] = {
+               .type = REISER4_ITEM_PLUGIN_TYPE,
+               .id = STATIC_STAT_DATA_ID
+       },
+       [PSET_DIR_ITEM] = {
+               .type = REISER4_ITEM_PLUGIN_TYPE,
+               .id = COMPOUND_DIR_ID
+       },
+       [PSET_CIPHER] = {
+               .type = REISER4_CIPHER_PLUGIN_TYPE,
+               .id = NONE_CIPHER_ID
+       },
+       [PSET_DIGEST] = {
+               .type = REISER4_DIGEST_PLUGIN_TYPE,
+               .id = SHA256_32_DIGEST_ID
+       },
+       [PSET_COMPRESSION] = {
+               .type = REISER4_COMPRESSION_PLUGIN_TYPE,
+               .id = LZO1_COMPRESSION_ID
+       },
+       [PSET_COMPRESSION_MODE] = {
+               .type = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+               .id = CONVX_COMPRESSION_MODE_ID
+       },
+       [PSET_CLUSTER] = {
+               .type = REISER4_CLUSTER_PLUGIN_TYPE,
+               .id = CLUSTER_64K_ID
+       },
+       [PSET_CREATE] = {
+               .type = REISER4_FILE_PLUGIN_TYPE,
+               .id = UNIX_FILE_PLUGIN_ID
+       }
+};
+
+/* access to default plugin table */
+reiser4_plugin *get_default_plugin(pset_member memb)
+{
+       return plugin_by_id(default_plugins[memb].type,
+                           default_plugins[memb].id);
+}
+
+/**
+ * reiser4_init_root_inode - obtain inode of root directory
+ * @super: super block of filesystem
+ *
+ * Obtains inode of root directory (reading it from disk), initializes plugin
+ * set it was not initialized.
+ */
+int reiser4_init_root_inode(struct super_block *super)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(super);
+       struct inode *inode;
+       int result = 0;
+
+       inode = reiser4_iget(super, sbinfo->df_plug->root_dir_key(super), 0);
+       if (IS_ERR(inode))
+               return RETERR(PTR_ERR(inode));
+
+       super->s_root = d_alloc_root(inode);
+       if (!super->s_root) {
+               iput(inode);
+               return RETERR(-ENOMEM);
+       }
+
+       super->s_root->d_op = &sbinfo->ops.dentry;
+
+       if (!is_inode_loaded(inode)) {
+               pset_member memb;
+               plugin_set *pset;
+
+               pset = reiser4_inode_data(inode)->pset;
+               for (memb = 0; memb < PSET_LAST; ++memb) {
+
+                       if (aset_get(pset, memb) != NULL)
+                               continue;
+
+                       result = grab_plugin_pset(inode, NULL, memb);
+                       if (result != 0)
+                               break;
+
+                       reiser4_inode_clr_flag(inode, REISER4_SDLEN_KNOWN);
+               }
+
+               if (result == 0) {
+                       if (REISER4_DEBUG) {
+                               for (memb = 0; memb < PSET_LAST; ++memb)
+                                       assert("nikita-3500",
+                                              aset_get(pset, memb) != NULL);
+                       }
+               } else
+                       warning("nikita-3448", "Cannot set plugins of root: %i",
+                               result);
+               reiser4_iget_complete(inode);
+
+               /* As the default pset kept in the root dir may has been changed
+                  (length is unknown), call update_sd. */
+               if (!reiser4_inode_get_flag(inode, REISER4_SDLEN_KNOWN)) {
+                       result = reiser4_grab_space(
+                               inode_file_plugin(inode)->estimate.update(inode),
+                               BA_CAN_COMMIT);
+
+                       if (result == 0)
+                               result = reiser4_update_sd(inode);
+
+                       all_grabbed2free();
+               }
+       }
+
+       super->s_maxbytes = MAX_LFS_FILESIZE;
+       return result;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/inode.c linux-2.6.20/fs/reiser4/inode.c
--- linux-2.6.20.orig/fs/reiser4/inode.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/inode.c     2007-05-06 14:50:43.726984474 +0400
@@ -0,0 +1,709 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Inode specific operations. */
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "kassign.h"
+#include "coord.h"
+#include "seal.h"
+#include "dscale.h"
+#include "plugin/item/item.h"
+#include "plugin/security/perm.h"
+#include "plugin/plugin.h"
+#include "plugin/object.h"
+#include "znode.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/fs.h>          /* for struct super_block,  address_space */
+
+/* return reiser4 internal tree which inode belongs to */
+/* Audited by: green(2002.06.17) */
+reiser4_tree *reiser4_tree_by_inode(const struct inode *inode /* inode queried */ )
+{
+       assert("nikita-256", inode != NULL);
+       assert("nikita-257", inode->i_sb != NULL);
+       return reiser4_get_tree(inode->i_sb);
+}
+
+/* return reiser4-specific inode flags */
+static inline unsigned long *inode_flags(const struct inode *const inode)
+{
+       assert("nikita-2842", inode != NULL);
+       return &reiser4_inode_data(inode)->flags;
+}
+
+/* set reiser4-specific flag @f in @inode */
+void reiser4_inode_set_flag(struct inode *inode, reiser4_file_plugin_flags f)
+{
+       assert("nikita-2248", inode != NULL);
+       set_bit((int)f, inode_flags(inode));
+}
+
+/* clear reiser4-specific flag @f in @inode */
+void reiser4_inode_clr_flag(struct inode *inode, reiser4_file_plugin_flags f)
+{
+       assert("nikita-2250", inode != NULL);
+       clear_bit((int)f, inode_flags(inode));
+}
+
+/* true if reiser4-specific flag @f is set in @inode */
+int reiser4_inode_get_flag(const struct inode *inode,
+                          reiser4_file_plugin_flags f)
+{
+       assert("nikita-2251", inode != NULL);
+       return test_bit((int)f, inode_flags(inode));
+}
+
+/* convert oid to inode number */
+ino_t oid_to_ino(oid_t oid)
+{
+       return (ino_t) oid;
+}
+
+/* convert oid to user visible inode number */
+ino_t oid_to_uino(oid_t oid)
+{
+       /* reiser4 object is uniquely identified by oid which is 64 bit
+          quantity. Kernel in-memory inode is indexed (in the hash table) by
+          32 bit i_ino field, but this is not a problem, because there is a
+          way to further distinguish inodes with identical inode numbers
+          (find_actor supplied to iget()).
+
+          But user space expects unique 32 bit inode number. Obviously this
+          is impossible. Work-around is to somehow hash oid into user visible
+          inode number.
+        */
+       oid_t max_ino = (ino_t) ~ 0;
+
+       if (REISER4_INO_IS_OID || (oid <= max_ino))
+               return oid;
+       else
+               /* this is remotely similar to algorithm used to find next pid
+                  to use for process: after wrap-around start from some
+                  offset rather than from 0. Idea is that there are some long
+                  living objects with which we don't want to collide.
+                */
+               return REISER4_UINO_SHIFT + ((oid - max_ino) & (max_ino >> 1));
+}
+
+/* check that "inode" is on reiser4 file-system */
+int is_reiser4_inode(const struct inode *inode /* inode queried */ )
+{
+       return inode != NULL && is_reiser4_super(inode->i_sb);
+}
+
+/* Maximal length of a name that can be stored in directory @inode.
+
+   This is used in check during file creation and lookup. */
+int reiser4_max_filename_len(const struct inode *inode /* inode queried */ )
+{
+       assert("nikita-287", is_reiser4_inode(inode));
+       assert("nikita-1710", inode_dir_item_plugin(inode));
+       if (inode_dir_item_plugin(inode)->s.dir.max_name_len)
+               return inode_dir_item_plugin(inode)->s.dir.max_name_len(inode);
+       else
+               return 255;
+}
+
+#if REISER4_USE_COLLISION_LIMIT
+/* Maximal number of hash collisions for this directory. */
+int max_hash_collisions(const struct inode *dir /* inode queried */ )
+{
+       assert("nikita-1711", dir != NULL);
+       return reiser4_inode_data(dir)->plugin.max_collisions;
+}
+#endif  /*  REISER4_USE_COLLISION_LIMIT  */
+
+/* Install file, inode, and address_space operation on @inode, depending on
+   its mode. */
+int setup_inode_ops(struct inode *inode /* inode to intialize */ ,
+                   reiser4_object_create_data * data   /* parameters to create
+                                                        * object */ )
+{
+       reiser4_super_info_data *sinfo;
+       file_plugin *fplug;
+       dir_plugin *dplug;
+
+       fplug = inode_file_plugin(inode);
+       dplug = inode_dir_plugin(inode);
+
+       sinfo = get_super_private(inode->i_sb);
+
+       switch (inode->i_mode & S_IFMT) {
+       case S_IFSOCK:
+       case S_IFBLK:
+       case S_IFCHR:
+       case S_IFIFO:
+               {
+                       dev_t rdev;     /* to keep gcc happy */
+
+                       assert("vs-46", fplug != NULL);
+                       /* ugly hack with rdev */
+                       if (data == NULL) {
+                               rdev = inode->i_rdev;
+                               inode->i_rdev = 0;
+                       } else
+                               rdev = data->rdev;
+                       inode->i_blocks = 0;
+                       assert("vs-42", fplug->h.id == SPECIAL_FILE_PLUGIN_ID);
+                       inode->i_op = &file_plugins[fplug->h.id].inode_ops;
+                       /* initialize inode->i_fop and inode->i_rdev for block and char
+                          devices */
+                       init_special_inode(inode, inode->i_mode, rdev);
+                       /* all address space operations are null */
+                       inode->i_mapping->a_ops =
+                           &file_plugins[fplug->h.id].as_ops;
+                       break;
+               }
+       case S_IFLNK:
+               assert("vs-46", fplug != NULL);
+               assert("vs-42", fplug->h.id == SYMLINK_FILE_PLUGIN_ID);
+               inode->i_op = &file_plugins[fplug->h.id].inode_ops;
+               inode->i_fop = NULL;
+               /* all address space operations are null */
+               inode->i_mapping->a_ops = &file_plugins[fplug->h.id].as_ops;
+               break;
+       case S_IFDIR:
+               assert("vs-46", dplug != NULL);
+               assert("vs-43", (dplug->h.id == HASHED_DIR_PLUGIN_ID ||
+                                dplug->h.id == SEEKABLE_HASHED_DIR_PLUGIN_ID));
+               inode->i_op = &dir_plugins[dplug->h.id].inode_ops;
+               inode->i_fop = &dir_plugins[dplug->h.id].file_ops;
+               inode->i_mapping->a_ops = &dir_plugins[dplug->h.id].as_ops;
+               break;
+       case S_IFREG:
+               assert("vs-46", fplug != NULL);
+               assert("vs-43", (fplug->h.id == UNIX_FILE_PLUGIN_ID ||
+                                fplug->h.id == CRYPTCOMPRESS_FILE_PLUGIN_ID));
+               inode->i_op = &file_plugins[fplug->h.id].inode_ops;
+               inode->i_fop = &file_plugins[fplug->h.id].file_ops;
+               inode->i_mapping->a_ops = &file_plugins[fplug->h.id].as_ops;
+               break;
+       default:
+               warning("nikita-291", "wrong file mode: %o for %llu",
+                       inode->i_mode,
+                       (unsigned long long)get_inode_oid(inode));
+               reiser4_make_bad_inode(inode);
+               return RETERR(-EINVAL);
+       }
+       return 0;
+}
+
+/* Initialize inode from disk data. Called with inode locked.
+   Return inode locked. */
+static int init_inode(struct inode *inode /* inode to intialise */ ,
+                     coord_t * coord /* coord of stat data */ )
+{
+       int result;
+       item_plugin *iplug;
+       void *body;
+       int length;
+       reiser4_inode *state;
+
+       assert("nikita-292", coord != NULL);
+       assert("nikita-293", inode != NULL);
+
+       coord_clear_iplug(coord);
+       result = zload(coord->node);
+       if (result)
+               return result;
+       iplug = item_plugin_by_coord(coord);
+       body = item_body_by_coord(coord);
+       length = item_length_by_coord(coord);
+
+       assert("nikita-295", iplug != NULL);
+       assert("nikita-296", body != NULL);
+       assert("nikita-297", length > 0);
+
+       /* inode is under I_LOCK now */
+
+       state = reiser4_inode_data(inode);
+       /* call stat-data plugin method to load sd content into inode */
+       result = iplug->s.sd.init_inode(inode, body, length);
+       set_plugin(&state->pset, PSET_SD, item_plugin_to_plugin(iplug));
+       if (result == 0) {
+               result = setup_inode_ops(inode, NULL);
+               if (result == 0 && inode->i_sb->s_root &&
+                   inode->i_sb->s_root->d_inode)
+                       result = finish_pset(inode);
+       }
+       zrelse(coord->node);
+       return result;
+}
+
+/* read `inode' from the disk. This is what was previously in
+   reiserfs_read_inode2().
+
+   Must be called with inode locked. Return inode still locked.
+*/
+static int read_inode(struct inode *inode /* inode to read from disk */ ,
+                     const reiser4_key * key /* key of stat data */ ,
+                     int silent)
+{
+       int result;
+       lock_handle lh;
+       reiser4_inode *info;
+       coord_t coord;
+
+       assert("nikita-298", inode != NULL);
+       assert("nikita-1945", !is_inode_loaded(inode));
+
+       info = reiser4_inode_data(inode);
+       assert("nikita-300", info->locality_id != 0);
+
+       coord_init_zero(&coord);
+       init_lh(&lh);
+       /* locate stat-data in a tree and return znode locked */
+       result = lookup_sd(inode, ZNODE_READ_LOCK, &coord, &lh, key, silent);
+       assert("nikita-301", !is_inode_loaded(inode));
+       if (result == 0) {
+               /* use stat-data plugin to load sd into inode. */
+               result = init_inode(inode, &coord);
+               if (result == 0) {
+                       /* initialize stat-data seal */
+                       spin_lock_inode(inode);
+                       reiser4_seal_init(&info->sd_seal, &coord, key);
+                       info->sd_coord = coord;
+                       spin_unlock_inode(inode);
+
+                       /* call file plugin's method to initialize plugin
+                        * specific part of inode */
+                       if (inode_file_plugin(inode)->init_inode_data)
+                               inode_file_plugin(inode)->init_inode_data(inode,
+                                                                         NULL,
+                                                                         0);
+                       /* load detached directory cursors for stateless
+                        * directory readers (NFS). */
+                       reiser4_load_cursors(inode);
+
+                       /* Check the opened inode for consistency. */
+                       result =
+                           get_super_private(inode->i_sb)->df_plug->
+                           check_open(inode);
+               }
+       }
+       /* lookup_sd() doesn't release coord because we want znode
+          stay read-locked while stat-data fields are accessed in
+          init_inode() */
+       done_lh(&lh);
+
+       if (result != 0)
+               reiser4_make_bad_inode(inode);
+       return result;
+}
+
+/* initialise new reiser4 inode being inserted into hash table. */
+static int init_locked_inode(struct inode *inode /* new inode */ ,
+                            void *opaque       /* key of stat data passed to the
+                                                * iget5_locked as cookie */ )
+{
+       reiser4_key *key;
+
+       assert("nikita-1995", inode != NULL);
+       assert("nikita-1996", opaque != NULL);
+       key = opaque;
+       set_inode_oid(inode, get_key_objectid(key));
+       reiser4_inode_data(inode)->locality_id = get_key_locality(key);
+       return 0;
+}
+
+/* reiser4_inode_find_actor() - "find actor" supplied by reiser4 to iget5_locked().
+
+   This function is called by iget5_locked() to distinguish reiser4 inodes
+   having the same inode numbers. Such inodes can only exist due to some error
+   condition. One of them should be bad. Inodes with identical inode numbers
+   (objectids) are distinguished by their packing locality.
+
+*/
+static int reiser4_inode_find_actor(struct inode *inode        /* inode from hash table to
+                                                        * check */ ,
+                                   void *opaque        /* "cookie" passed to
+                                                        * iget5_locked(). This is stat data
+                                                        * key */ )
+{
+       reiser4_key *key;
+
+       key = opaque;
+       return
+           /* oid is unique, so first term is enough, actually. */
+           get_inode_oid(inode) == get_key_objectid(key) &&
+           /*
+            * also, locality should be checked, but locality is stored in
+            * the reiser4-specific part of the inode, and actor can be
+            * called against arbitrary inode that happened to be in this
+            * hash chain. Hence we first have to check that this is
+            * reiser4 inode at least. is_reiser4_inode() is probably too
+            * early to call, as inode may have ->i_op not yet
+            * initialised.
+            */
+           is_reiser4_super(inode->i_sb) &&
+           /*
+            * usually objectid is unique, but pseudo files use counter to
+            * generate objectid. All pseudo files are placed into special
+            * (otherwise unused) locality.
+            */
+           reiser4_inode_data(inode)->locality_id == get_key_locality(key);
+}
+
+/* hook for kmem_cache_create */
+void loading_init_once(reiser4_inode * info)
+{
+       mutex_init(&info->loading);
+}
+
+/* for reiser4_alloc_inode */
+void loading_alloc(reiser4_inode * info)
+{
+       assert("vs-1717", !mutex_is_locked(&info->loading));
+}
+
+/* for reiser4_destroy */
+void loading_destroy(reiser4_inode * info)
+{
+       assert("vs-1717a", !mutex_is_locked(&info->loading));
+}
+
+static void loading_begin(reiser4_inode * info)
+{
+       mutex_lock(&info->loading);
+}
+
+static void loading_end(reiser4_inode * info)
+{
+       mutex_unlock(&info->loading);
+}
+
+/**
+ * reiser4_iget - obtain inode via iget5_locked, read from disk if necessary
+ * @super: super block of filesystem
+ * @key: key of inode's stat-data
+ * @silent:
+ *
+ * This is our helper function a la iget(). This is be called by
+ * lookup_common() and reiser4_read_super(). Return inode locked or error
+ * encountered.
+ */
+struct inode *reiser4_iget(struct super_block *super, const reiser4_key *key,
+                          int silent)
+{
+       struct inode *inode;
+       int result;
+       reiser4_inode *info;
+
+       assert("nikita-302", super != NULL);
+       assert("nikita-303", key != NULL);
+
+       result = 0;
+
+       /* call iget(). Our ->read_inode() is dummy, so this will either
+          find inode in cache or return uninitialised inode */
+       inode = iget5_locked(super,
+                            (unsigned long)get_key_objectid(key),
+                            reiser4_inode_find_actor,
+                            init_locked_inode, (reiser4_key *) key);
+       if (inode == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+       if (is_bad_inode(inode)) {
+               warning("nikita-304", "Bad inode found");
+               reiser4_print_key("key", key);
+               iput(inode);
+               return ERR_PTR(RETERR(-EIO));
+       }
+
+       info = reiser4_inode_data(inode);
+
+       /* Reiser4 inode state bit REISER4_LOADED is used to distinguish fully
+          loaded and initialized inode from just allocated inode. If
+          REISER4_LOADED bit is not set, reiser4_iget() completes loading under
+          info->loading.  The place in reiser4 which uses not initialized inode
+          is the reiser4 repacker, see repacker-related functions in
+          plugin/item/extent.c */
+       if (!is_inode_loaded(inode)) {
+               loading_begin(info);
+               if (!is_inode_loaded(inode)) {
+                       /* locking: iget5_locked returns locked inode */
+                       assert("nikita-1941", !is_inode_loaded(inode));
+                       assert("nikita-1949",
+                              reiser4_inode_find_actor(inode,
+                                                       (reiser4_key *) key));
+                       /* now, inode has objectid as ->i_ino and locality in
+                          reiser4-specific part. This is enough for
+                          read_inode() to read stat data from the disk */
+                       result = read_inode(inode, key, silent);
+               } else
+                       loading_end(info);
+       }
+
+       if (inode->i_state & I_NEW)
+               unlock_new_inode(inode);
+
+       if (is_bad_inode(inode)) {
+               assert("vs-1717", result != 0);
+               loading_end(info);
+               iput(inode);
+               inode = ERR_PTR(result);
+       } else if (REISER4_DEBUG) {
+               reiser4_key found_key;
+
+               assert("vs-1717", result == 0);
+               build_sd_key(inode, &found_key);
+               if (!keyeq(&found_key, key)) {
+                       warning("nikita-305", "Wrong key in sd");
+                       reiser4_print_key("sought for", key);
+                       reiser4_print_key("found", &found_key);
+               }
+               if (inode->i_nlink == 0) {
+                       warning("nikita-3559", "Unlinked inode found: %llu\n",
+                               (unsigned long long)get_inode_oid(inode));
+               }
+       }
+       return inode;
+}
+
+/* reiser4_iget() may return not fully initialized inode, this function should
+ * be called after one completes reiser4 inode initializing. */
+void reiser4_iget_complete(struct inode *inode)
+{
+       assert("zam-988", is_reiser4_inode(inode));
+
+       if (!is_inode_loaded(inode)) {
+               reiser4_inode_set_flag(inode, REISER4_LOADED);
+               loading_end(reiser4_inode_data(inode));
+       }
+}
+
+void reiser4_make_bad_inode(struct inode *inode)
+{
+       assert("nikita-1934", inode != NULL);
+
+       /* clear LOADED bit */
+       reiser4_inode_clr_flag(inode, REISER4_LOADED);
+       make_bad_inode(inode);
+       return;
+}
+
+file_plugin *inode_file_plugin(const struct inode * inode)
+{
+       assert("nikita-1997", inode != NULL);
+       return reiser4_inode_data(inode)->pset->file;
+}
+
+dir_plugin *inode_dir_plugin(const struct inode * inode)
+{
+       assert("nikita-1998", inode != NULL);
+       return reiser4_inode_data(inode)->pset->dir;
+}
+
+formatting_plugin *inode_formatting_plugin(const struct inode * inode)
+{
+       assert("nikita-2000", inode != NULL);
+       return reiser4_inode_data(inode)->pset->formatting;
+}
+
+hash_plugin *inode_hash_plugin(const struct inode * inode)
+{
+       assert("nikita-2001", inode != NULL);
+       return reiser4_inode_data(inode)->pset->hash;
+}
+
+fibration_plugin *inode_fibration_plugin(const struct inode * inode)
+{
+       assert("nikita-2001", inode != NULL);
+       return reiser4_inode_data(inode)->pset->fibration;
+}
+
+cipher_plugin *inode_cipher_plugin(const struct inode * inode)
+{
+       assert("edward-36", inode != NULL);
+       return reiser4_inode_data(inode)->pset->cipher;
+}
+
+compression_plugin *inode_compression_plugin(const struct inode * inode)
+{
+       assert("edward-37", inode != NULL);
+       return reiser4_inode_data(inode)->pset->compression;
+}
+
+compression_mode_plugin *inode_compression_mode_plugin(const struct inode *
+                                                      inode)
+{
+       assert("edward-1330", inode != NULL);
+       return reiser4_inode_data(inode)->pset->compression_mode;
+}
+
+cluster_plugin *inode_cluster_plugin(const struct inode * inode)
+{
+       assert("edward-1328", inode != NULL);
+       return reiser4_inode_data(inode)->pset->cluster;
+}
+
+file_plugin *inode_create_plugin(const struct inode * inode)
+{
+       assert("edward-1329", inode != NULL);
+       return reiser4_inode_data(inode)->pset->create;
+}
+
+digest_plugin *inode_digest_plugin(const struct inode * inode)
+{
+       assert("edward-86", inode != NULL);
+       return reiser4_inode_data(inode)->pset->digest;
+}
+
+item_plugin *inode_sd_plugin(const struct inode * inode)
+{
+       assert("vs-534", inode != NULL);
+       return reiser4_inode_data(inode)->pset->sd;
+}
+
+item_plugin *inode_dir_item_plugin(const struct inode * inode)
+{
+       assert("vs-534", inode != NULL);
+       return reiser4_inode_data(inode)->pset->dir_item;
+}
+
+file_plugin *child_create_plugin(const struct inode * inode)
+{
+       assert("edward-1329", inode != NULL);
+       return reiser4_inode_data(inode)->hset->create;
+}
+
+void inode_set_extension(struct inode *inode, sd_ext_bits ext)
+{
+       reiser4_inode *state;
+
+       assert("nikita-2716", inode != NULL);
+       assert("nikita-2717", ext < LAST_SD_EXTENSION);
+       assert("nikita-3491", spin_inode_is_locked(inode));
+
+       state = reiser4_inode_data(inode);
+       state->extmask |= 1 << ext;
+       /* force re-calculation of stat-data length on next call to
+          update_sd(). */
+       reiser4_inode_clr_flag(inode, REISER4_SDLEN_KNOWN);
+}
+
+void inode_clr_extension(struct inode *inode, sd_ext_bits ext)
+{
+       reiser4_inode *state;
+
+       assert("vpf-1926", inode != NULL);
+       assert("vpf-1927", ext < LAST_SD_EXTENSION);
+       assert("vpf-1928", spin_inode_is_locked(inode));
+
+       state = reiser4_inode_data(inode);
+       state->extmask &= ~(1 << ext);
+       /* force re-calculation of stat-data length on next call to
+          update_sd(). */
+       reiser4_inode_clr_flag(inode, REISER4_SDLEN_KNOWN);
+}
+
+void inode_check_scale_nolock(struct inode *inode, __u64 old, __u64 new)
+{
+       assert("edward-1287", inode != NULL);
+       if (!dscale_fit(old, new))
+               reiser4_inode_clr_flag(inode, REISER4_SDLEN_KNOWN);
+       return;
+}
+
+void inode_check_scale(struct inode *inode, __u64 old, __u64 new)
+{
+       assert("nikita-2875", inode != NULL);
+       spin_lock_inode(inode);
+       inode_check_scale_nolock(inode, old, new);
+       spin_unlock_inode(inode);
+}
+
+/*
+ * initialize ->ordering field of inode. This field defines how file stat-data
+ * and body is ordered within a tree with respect to other objects within the
+ * same parent directory.
+ */
+void
+init_inode_ordering(struct inode *inode,
+                   reiser4_object_create_data * crd, int create)
+{
+       reiser4_key key;
+
+       if (create) {
+               struct inode *parent;
+
+               parent = crd->parent;
+               assert("nikita-3224", inode_dir_plugin(parent) != NULL);
+               inode_dir_plugin(parent)->build_entry_key(parent,
+                                                         &crd->dentry->d_name,
+                                                         &key);
+       } else {
+               coord_t *coord;
+
+               coord = &reiser4_inode_data(inode)->sd_coord;
+               coord_clear_iplug(coord);
+               /* safe to use ->sd_coord, because node is under long term
+                * lock */
+               WITH_DATA(coord->node, item_key_by_coord(coord, &key));
+       }
+
+       set_inode_ordering(inode, get_key_ordering(&key));
+}
+
+znode *inode_get_vroot(struct inode *inode)
+{
+       reiser4_block_nr blk;
+       znode *result;
+
+       spin_lock_inode(inode);
+       blk = reiser4_inode_data(inode)->vroot;
+       spin_unlock_inode(inode);
+       if (!disk_addr_eq(&UBER_TREE_ADDR, &blk))
+               result = zlook(reiser4_tree_by_inode(inode), &blk);
+       else
+               result = NULL;
+       return result;
+}
+
+void inode_set_vroot(struct inode *inode, znode *vroot)
+{
+       spin_lock_inode(inode);
+       reiser4_inode_data(inode)->vroot = *znode_get_block(vroot);
+       spin_unlock_inode(inode);
+}
+
+#if REISER4_DEBUG
+
+void reiser4_inode_invariant(const struct inode *inode)
+{
+       assert("nikita-3077", spin_inode_is_locked(inode));
+}
+
+int inode_has_no_jnodes(reiser4_inode * r4_inode)
+{
+       return jnode_tree_by_reiser4_inode(r4_inode)->rnode == NULL &&
+               r4_inode->nr_jnodes == 0;
+}
+
+#endif
+
+/* true if directory is empty (only contains dot and dotdot) */
+/* FIXME: shouldn't it be dir plugin method? */
+int is_dir_empty(const struct inode *dir)
+{
+       assert("nikita-1976", dir != NULL);
+
+       /* rely on our method to maintain directory i_size being equal to the
+          number of entries. */
+       return dir->i_size <= 2 ? 0 : RETERR(-ENOTEMPTY);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/inode.h linux-2.6.20/fs/reiser4/inode.h
--- linux-2.6.20.orig/fs/reiser4/inode.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/inode.h     2007-05-06 14:50:43.726984474 +0400
@@ -0,0 +1,438 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Inode functions. */
+
+#if !defined( __REISER4_INODE_H__ )
+#define __REISER4_INODE_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "seal.h"
+#include "plugin/plugin.h"
+#include "plugin/file/cryptcompress.h"
+#include "plugin/file/file.h"
+#include "plugin/dir/dir.h"
+#include "plugin/plugin_set.h"
+#include "plugin/security/perm.h"
+#include "vfs_ops.h"
+#include "jnode.h"
+#include "fsdata.h"
+
+#include <linux/types.h>       /* for __u?? , ino_t */
+#include <linux/fs.h>          /* for struct super_block, struct
+                                * rw_semaphore, etc  */
+#include <linux/spinlock.h>
+#include <asm/types.h>
+
+/* reiser4-specific inode flags. They are "transient" and are not
+   supposed to be stored on disk. Used to trace "state" of
+   inode
+*/
+typedef enum {
+       /* this is light-weight inode, inheriting some state from its
+          parent  */
+       REISER4_LIGHT_WEIGHT = 0,
+       /* stat data wasn't yet created */
+       REISER4_NO_SD = 1,
+       /* internal immutable flag. Currently is only used
+          to avoid race condition during file creation.
+          See comment in create_object(). */
+       REISER4_IMMUTABLE = 2,
+       /* inode was read from storage */
+       REISER4_LOADED = 3,
+       /* this bit is set for symlinks. inode->i_private points to target
+          name of symlink. */
+       REISER4_GENERIC_PTR_USED = 4,
+       /* set if size of stat-data item for this inode is known. If this is
+        * set we can avoid recalculating size of stat-data on each update. */
+       REISER4_SDLEN_KNOWN = 5,
+       /* reiser4_inode->crypt points to the crypto stat */
+       REISER4_CRYPTO_STAT_LOADED = 6,
+       /* cryptcompress_inode_data points to the secret key */
+       REISER4_SECRET_KEY_INSTALLED = 7,
+       /* File (possibly) has pages corresponding to the tail items, that
+        * were created by ->readpage. It is set by mmap_unix_file() and
+        * sendfile_unix_file(). This bit is inspected by write_unix_file and
+        * kill-hook of tail items. It is never cleared once set. This bit is
+        * modified and inspected under i_mutex. */
+       REISER4_HAS_MMAP = 8,
+       REISER4_PART_MIXED = 9,
+       REISER4_PART_IN_CONV = 10,
+       /* This flag indicates that file plugin conversion is in progress */
+       REISER4_FILE_CONV_IN_PROGRESS = 11
+} reiser4_file_plugin_flags;
+
+/* state associated with each inode.
+   reiser4 inode.
+
+   NOTE-NIKITA In 2.5 kernels it is not necessary that all file-system inodes
+   be of the same size. File-system allocates inodes by itself through
+   s_op->allocate_inode() method. So, it is possible to adjust size of inode
+   at the time of its creation.
+
+   Invariants involving parts of this data-type:
+
+      [inode->eflushed]
+
+*/
+
+typedef struct reiser4_inode reiser4_inode;
+/* return pointer to reiser4-specific part of inode */
+static inline reiser4_inode *reiser4_inode_data(const struct inode *inode
+                                               /* inode queried */ );
+
+#if BITS_PER_LONG == 64
+
+#define REISER4_INO_IS_OID (1)
+typedef struct {;
+} oid_hi_t;
+
+/* BITS_PER_LONG == 64 */
+#else
+
+#define REISER4_INO_IS_OID (0)
+typedef __u32 oid_hi_t;
+
+/* BITS_PER_LONG == 64 */
+#endif
+
+struct reiser4_inode {
+       /* spin lock protecting fields of this structure. */
+       spinlock_t guard;
+       /* main plugin set that control the file
+          (see comments in plugin/plugin_set.c) */
+       plugin_set *pset;
+       /* plugin set for inheritance
+          (see comments in plugin/plugin_set.c) */
+       plugin_set *hset;
+       /* high 32 bits of object id */
+       oid_hi_t oid_hi;
+       /* seal for stat-data */
+       seal_t sd_seal;
+       /* locality id for this file */
+       oid_t locality_id;
+#if REISER4_LARGE_KEY
+       __u64 ordering;
+#endif
+       /* coord of stat-data in sealed node */
+       coord_t sd_coord;
+       /* bit-mask of stat-data extentions used by this file */
+       __u64 extmask;
+       /* bitmask of non-default plugins for this inode */
+       __u16 plugin_mask;
+       /* bitmask of set heir plugins for this inode. */
+       __u16 heir_mask;
+       union {
+               struct list_head readdir_list;
+               struct list_head not_used;
+       } lists;
+       /* per-inode flags. Filled by values of reiser4_file_plugin_flags */
+       unsigned long flags;
+       union {
+               /* fields specific to unix_file plugin */
+               unix_file_info_t unix_file_info;
+               /* fields specific to cryptcompress plugin */
+               cryptcompress_info_t cryptcompress_info;
+       } file_plugin_data;
+
+       /* this semaphore is to serialize readers and writers of @pset->file
+        * when file plugin conversion is enabled
+        */
+       struct rw_semaphore conv_sem;
+
+       /* tree of jnodes. Phantom jnodes (ones not attched to any atom) are
+          tagged in that tree by EFLUSH_TAG_ANONYMOUS */
+       struct radix_tree_root jnodes_tree;
+#if REISER4_DEBUG
+       /* number of unformatted node jnodes of this file in jnode hash table */
+       unsigned long nr_jnodes;
+#endif
+
+       /* block number of virtual root for this object. See comment above
+        * fs/reiser4/search.c:handle_vroot() */
+       reiser4_block_nr vroot;
+       struct mutex loading;
+};
+
+void loading_init_once(reiser4_inode *);
+void loading_alloc(reiser4_inode *);
+void loading_destroy(reiser4_inode *);
+
+typedef struct reiser4_inode_object {
+       /* private part */
+       reiser4_inode p;
+       /* generic fields not specific to reiser4, but used by VFS */
+       struct inode vfs_inode;
+} reiser4_inode_object;
+
+/* return pointer to the reiser4 specific portion of @inode */
+static inline reiser4_inode *reiser4_inode_data(const struct inode *inode
+                                               /* inode queried */ )
+{
+       assert("nikita-254", inode != NULL);
+       return &container_of(inode, reiser4_inode_object, vfs_inode)->p;
+}
+
+static inline struct inode *inode_by_reiser4_inode(const reiser4_inode *
+                                                  r4_inode /* inode queried */
+                                                  )
+{
+       return &container_of(r4_inode, reiser4_inode_object, p)->vfs_inode;
+}
+
+/*
+ * reiser4 inodes are identified by 64bit object-id (oid_t), but in struct
+ * inode ->i_ino field is of type ino_t (long) that can be either 32 or 64
+ * bits.
+ *
+ * If ->i_ino is 32 bits we store remaining 32 bits in reiser4 specific part
+ * of inode, otherwise whole oid is stored in i_ino.
+ *
+ * Wrappers below ([sg]et_inode_oid()) are used to hide this difference.
+ */
+
+#define OID_HI_SHIFT (sizeof(ino_t) * 8)
+
+#if REISER4_INO_IS_OID
+
+static inline oid_t get_inode_oid(const struct inode *inode)
+{
+       return inode->i_ino;
+}
+
+static inline void set_inode_oid(struct inode *inode, oid_t oid)
+{
+       inode->i_ino = oid;
+}
+
+/* REISER4_INO_IS_OID */
+#else
+
+static inline oid_t get_inode_oid(const struct inode *inode)
+{
+       return
+           ((__u64) reiser4_inode_data(inode)->oid_hi << OID_HI_SHIFT) |
+           inode->i_ino;
+}
+
+static inline void set_inode_oid(struct inode *inode, oid_t oid)
+{
+       assert("nikita-2519", inode != NULL);
+       inode->i_ino = (ino_t) (oid);
+       reiser4_inode_data(inode)->oid_hi = (oid) >> OID_HI_SHIFT;
+       assert("nikita-2521", get_inode_oid(inode) == (oid));
+}
+
+/* REISER4_INO_IS_OID */
+#endif
+
+static inline oid_t get_inode_locality(const struct inode *inode)
+{
+       return reiser4_inode_data(inode)->locality_id;
+}
+
+#if REISER4_LARGE_KEY
+static inline __u64 get_inode_ordering(const struct inode *inode)
+{
+       return reiser4_inode_data(inode)->ordering;
+}
+
+static inline void set_inode_ordering(const struct inode *inode, __u64 ordering)
+{
+       reiser4_inode_data(inode)->ordering = ordering;
+}
+
+#else
+
+#define get_inode_ordering(inode) (0)
+#define set_inode_ordering(inode, val) noop
+
+#endif
+
+/* return inode in which @uf_info is embedded */
+static inline struct inode *unix_file_info_to_inode(const unix_file_info_t *
+                                                   uf_info)
+{
+       return &container_of(uf_info, reiser4_inode_object,
+                            p.file_plugin_data.unix_file_info)->vfs_inode;
+}
+
+extern ino_t oid_to_ino(oid_t oid) __attribute__ ((const));
+extern ino_t oid_to_uino(oid_t oid) __attribute__ ((const));
+
+extern reiser4_tree *reiser4_tree_by_inode(const struct inode *inode);
+
+#if REISER4_DEBUG
+extern void reiser4_inode_invariant(const struct inode *inode);
+extern int inode_has_no_jnodes(reiser4_inode *);
+#else
+#define reiser4_inode_invariant(inode) noop
+#endif
+
+static inline int spin_inode_is_locked(const struct inode *inode)
+{
+       assert_spin_locked(&reiser4_inode_data(inode)->guard);
+       return 1;
+}
+
+/**
+ * spin_lock_inode - lock reiser4_inode' embedded spinlock
+ * @inode: inode to lock
+ *
+ * In debug mode it checks that lower priority locks are not held and
+ * increments reiser4_context's lock counters on which lock ordering checking
+ * is based.
+ */
+static inline void spin_lock_inode(struct inode *inode)
+{
+       assert("", LOCK_CNT_NIL(spin_locked));
+       /* check lock ordering */
+       assert_spin_not_locked(&d_lock);
+
+       spin_lock(&reiser4_inode_data(inode)->guard);
+
+       LOCK_CNT_INC(spin_locked_inode);
+       LOCK_CNT_INC(spin_locked);
+
+       reiser4_inode_invariant(inode);
+}
+
+/**
+ * spin_unlock_inode - unlock reiser4_inode' embedded spinlock
+ * @inode: inode to unlock
+ *
+ * In debug mode it checks that spinlock is held and decrements
+ * reiser4_context's lock counters on which lock ordering checking is based.
+ */
+static inline void spin_unlock_inode(struct inode *inode)
+{
+       assert_spin_locked(&reiser4_inode_data(inode)->guard);
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_inode));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       reiser4_inode_invariant(inode);
+
+       LOCK_CNT_DEC(spin_locked_inode);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&reiser4_inode_data(inode)->guard);
+}
+
+extern znode *inode_get_vroot(struct inode *inode);
+extern void inode_set_vroot(struct inode *inode, znode * vroot);
+
+extern int reiser4_max_filename_len(const struct inode *inode);
+extern int max_hash_collisions(const struct inode *dir);
+extern void reiser4_unlock_inode(struct inode *inode);
+extern int is_reiser4_inode(const struct inode *inode);
+extern int setup_inode_ops(struct inode *inode, reiser4_object_create_data *);
+extern struct inode *reiser4_iget(struct super_block *super,
+                                 const reiser4_key * key, int silent);
+extern void reiser4_iget_complete(struct inode *inode);
+extern void reiser4_inode_set_flag(struct inode *inode, reiser4_file_plugin_flags f);
+extern void reiser4_inode_clr_flag(struct inode *inode, reiser4_file_plugin_flags f);
+extern int reiser4_inode_get_flag(const struct inode *inode,
+                                 reiser4_file_plugin_flags f);
+
+/*  has inode been initialized? */
+static inline int
+is_inode_loaded(const struct inode *inode /* inode queried */ )
+{
+       assert("nikita-1120", inode != NULL);
+       return reiser4_inode_get_flag(inode, REISER4_LOADED);
+}
+
+extern file_plugin *inode_file_plugin(const struct inode *inode);
+extern dir_plugin *inode_dir_plugin(const struct inode *inode);
+extern formatting_plugin *inode_formatting_plugin(const struct inode *inode);
+extern hash_plugin *inode_hash_plugin(const struct inode *inode);
+extern fibration_plugin *inode_fibration_plugin(const struct inode *inode);
+extern cipher_plugin *inode_cipher_plugin(const struct inode *inode);
+extern digest_plugin *inode_digest_plugin(const struct inode *inode);
+extern compression_plugin *inode_compression_plugin(const struct inode *inode);
+extern compression_mode_plugin *inode_compression_mode_plugin(const struct inode
+                                                             *inode);
+extern cluster_plugin *inode_cluster_plugin(const struct inode *inode);
+extern file_plugin *inode_create_plugin(const struct inode *inode);
+extern item_plugin *inode_sd_plugin(const struct inode *inode);
+extern item_plugin *inode_dir_item_plugin(const struct inode *inode);
+extern file_plugin *child_create_plugin(const struct inode *inode);
+
+extern void reiser4_make_bad_inode(struct inode *inode);
+
+extern void inode_set_extension(struct inode *inode, sd_ext_bits ext);
+extern void inode_clr_extension(struct inode *inode, sd_ext_bits ext);
+extern void inode_check_scale(struct inode *inode, __u64 old, __u64 new);
+extern void inode_check_scale_nolock(struct inode * inode, __u64 old, __u64 new);
+
+/*
+ * update field @field in inode @i to contain value @value.
+ */
+#define INODE_SET_FIELD(i, field, value)               \
+({                                                     \
+       struct inode *__i;                              \
+       typeof(value) __v;                              \
+                                                       \
+       __i = (i);                                      \
+       __v = (value);                                  \
+       inode_check_scale(__i, __i->field, __v);        \
+       __i->field = __v;                               \
+})
+
+#define INODE_INC_FIELD(i, field)                              \
+({                                                             \
+       struct inode *__i;                                      \
+                                                               \
+       __i = (i);                                              \
+       inode_check_scale(__i, __i->field, __i->field + 1);     \
+       ++ __i->field;                                          \
+})
+
+#define INODE_DEC_FIELD(i, field)                              \
+({                                                             \
+       struct inode *__i;                                      \
+                                                               \
+       __i = (i);                                              \
+       inode_check_scale(__i, __i->field, __i->field - 1);     \
+       -- __i->field;                                          \
+})
+
+/* See comment before reiser4_readdir_common() for description. */
+static inline struct list_head *get_readdir_list(const struct inode *inode)
+{
+       return &reiser4_inode_data(inode)->lists.readdir_list;
+}
+
+extern void init_inode_ordering(struct inode *inode,
+                               reiser4_object_create_data * crd, int create);
+
+static inline struct radix_tree_root *jnode_tree_by_inode(struct inode *inode)
+{
+       return &reiser4_inode_data(inode)->jnodes_tree;
+}
+
+static inline struct radix_tree_root *jnode_tree_by_reiser4_inode(reiser4_inode
+                                                                 * r4_inode)
+{
+       return &r4_inode->jnodes_tree;
+}
+
+#if REISER4_DEBUG
+extern void print_inode(const char *prefix, const struct inode *i);
+#endif
+
+int is_dir_empty(const struct inode *);
+
+/* __REISER4_INODE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/ioctl.h linux-2.6.20/fs/reiser4/ioctl.h
--- linux-2.6.20.orig/fs/reiser4/ioctl.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/ioctl.h     2007-05-06 14:50:43.726984474 +0400
@@ -0,0 +1,41 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#if !defined( __REISER4_IOCTL_H__ )
+#define __REISER4_IOCTL_H__
+
+#include <linux/fs.h>
+
+/*
+ * ioctl(2) command used to "unpack" reiser4 file, that is, convert it into
+ * extents and fix in this state. This is used by applications that rely on
+ *
+ *     . files being block aligned, and
+ *
+ *     . files never migrating on disk
+ *
+ * for example, boot loaders (LILO) need this.
+ *
+ * This ioctl should be used as
+ *
+ *     result = ioctl(fd, REISER4_IOC_UNPACK);
+ *
+ * File behind fd descriptor will be converted to the extents (if necessary),
+ * and its stat-data will be updated so that it will never be converted back
+ * into tails again.
+ */
+#define REISER4_IOC_UNPACK _IOW(0xCD,1,long)
+
+/* __REISER4_IOCTL_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/jnode.c linux-2.6.20/fs/reiser4/jnode.c
--- linux-2.6.20.orig/fs/reiser4/jnode.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/jnode.c     2007-05-06 14:50:43.730985723 +0400
@@ -0,0 +1,1925 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+/* Jnode manipulation functions. */
+/* Jnode is entity used to track blocks with data and meta-data in reiser4.
+
+   In particular, jnodes are used to track transactional information
+   associated with each block. Each znode contains jnode as ->zjnode field.
+
+   Jnode stands for either Josh or Journal node.
+*/
+
+/*
+ * Taxonomy.
+ *
+ *     Jnode represents block containing data or meta-data. There are jnodes
+ *     for:
+ *
+ *         unformatted blocks (jnodes proper). There are plans, however to
+ *         have a handle per extent unit rather than per each unformatted
+ *         block, because there are so many of them.
+ *
+ *         For bitmaps. Each bitmap is actually represented by two jnodes--one
+ *         for working and another for "commit" data, together forming bnode.
+ *
+ *         For io-heads. These are used by log writer.
+ *
+ *         For formatted nodes (znode). See comment at the top of znode.c for
+ *         details specific to the formatted nodes (znodes).
+ *
+ * Node data.
+ *
+ *     Jnode provides access to the data of node it represents. Data are
+ *     stored in a page. Page is kept in a page cache. This means, that jnodes
+ *     are highly interconnected with page cache and VM internals.
+ *
+ *     jnode has a pointer to page (->pg) containing its data. Pointer to data
+ *     themselves is cached in ->data field to avoid frequent calls to
+ *     page_address().
+ *
+ *     jnode and page are attached to each other by jnode_attach_page(). This
+ *     function places pointer to jnode in set_page_private(), sets PG_private
+ *     flag and increments page counter.
+ *
+ *     Opposite operation is performed by page_clear_jnode().
+ *
+ *     jnode->pg is protected by jnode spin lock, and page->private is
+ *     protected by page lock. See comment at the top of page_cache.c for
+ *     more.
+ *
+ *     page can be detached from jnode for two reasons:
+ *
+ *         . jnode is removed from a tree (file is truncated, of formatted
+ *         node is removed by balancing).
+ *
+ *         . during memory pressure, VM calls ->releasepage() method
+ *         (reiser4_releasepage()) to evict page from memory.
+ *
+ *    (there, of course, is also umount, but this is special case we are not
+ *    concerned with here).
+ *
+ *    To protect jnode page from eviction, one calls jload() function that
+ *    "pins" page in memory (loading it if necessary), increments
+ *    jnode->d_count, and kmap()s page. Page is unpinned through call to
+ *    jrelse().
+ *
+ * Jnode life cycle.
+ *
+ *    jnode is created, placed in hash table, and, optionally, in per-inode
+ *    radix tree. Page can be attached to jnode, pinned, released, etc.
+ *
+ *    When jnode is captured into atom its reference counter is
+ *    increased. While being part of an atom, jnode can be "early
+ *    flushed". This means that as part of flush procedure, jnode is placed
+ *    into "relocate set", and its page is submitted to the disk. After io
+ *    completes, page can be detached, then loaded again, re-dirtied, etc.
+ *
+ *    Thread acquired reference to jnode by calling jref() and releases it by
+ *    jput(). When last reference is removed, jnode is still retained in
+ *    memory (cached) if it has page attached, _unless_ it is scheduled for
+ *    destruction (has JNODE_HEARD_BANSHEE bit set).
+ *
+ *    Tree read-write lock was used as "existential" lock for jnodes. That is,
+ *    jnode->x_count could be changed from 0 to 1 only under tree write lock,
+ *    that is, tree lock protected unreferenced jnodes stored in the hash
+ *    table, from recycling.
+ *
+ *    This resulted in high contention on tree lock, because jref()/jput() is
+ *    frequent operation. To ameliorate this problem, RCU is used: when jput()
+ *    is just about to release last reference on jnode it sets JNODE_RIP bit
+ *    on it, and then proceed with jnode destruction (removing jnode from hash
+ *    table, cbk_cache, detaching page, etc.). All places that change jnode
+ *    reference counter from 0 to 1 (jlookup(), zlook(), zget(), and
+ *    cbk_cache_scan_slots()) check for JNODE_RIP bit (this is done by
+ *    jnode_rip_check() function), and pretend that nothing was found in hash
+ *    table if bit is set.
+ *
+ *    jput defers actual return of jnode into slab cache to some later time
+ *    (by call_rcu()), this guarantees that other threads can safely continue
+ *    working with JNODE_RIP-ped jnode.
+ *
+ */
+
+#include "reiser4.h"
+#include "debug.h"
+#include "dformat.h"
+#include "jnode.h"
+#include "plugin/plugin_header.h"
+#include "plugin/plugin.h"
+#include "txnmgr.h"
+/*#include "jnode.h"*/
+#include "znode.h"
+#include "tree.h"
+#include "tree_walk.h"
+#include "super.h"
+#include "inode.h"
+#include "page_cache.h"
+
+#include <asm/uaccess.h>       /* UML needs this for PAGE_OFFSET */
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/swap.h>
+#include <linux/fs.h>          /* for struct address_space  */
+#include <linux/writeback.h>   /* for inode_lock */
+
+static struct kmem_cache *_jnode_slab = NULL;
+
+static void jnode_set_type(jnode * node, jnode_type type);
+static int jdelete(jnode * node);
+static int jnode_try_drop(jnode * node);
+
+#if REISER4_DEBUG
+static int jnode_invariant(const jnode * node, int tlocked, int jlocked);
+#endif
+
+/* true if valid page is attached to jnode */
+static inline int jnode_is_parsed(jnode * node)
+{
+       return JF_ISSET(node, JNODE_PARSED);
+}
+
+/* hash table support */
+
+/* compare two jnode keys for equality. Used by hash-table macros */
+static inline int jnode_key_eq(const jnode_key_t * k1, const jnode_key_t * k2)
+{
+       assert("nikita-2350", k1 != NULL);
+       assert("nikita-2351", k2 != NULL);
+
+       return (k1->index == k2->index && k1->objectid == k2->objectid);
+}
+
+/* Hash jnode by its key (inode plus offset). Used by hash-table macros */
+static inline __u32
+jnode_key_hashfn(j_hash_table * table, const jnode_key_t * key)
+{
+       assert("nikita-2352", key != NULL);
+       assert("nikita-3346", IS_POW(table->_buckets));
+
+       /* yes, this is remarkable simply (where not stupid) hash function. */
+       return (key->objectid + key->index) & (table->_buckets - 1);
+}
+
+/* The hash table definition */
+#define KMALLOC(size) reiser4_vmalloc(size)
+#define KFREE(ptr, size) vfree(ptr)
+TYPE_SAFE_HASH_DEFINE(j, jnode, jnode_key_t, key.j, link.j, jnode_key_hashfn,
+                     jnode_key_eq);
+#undef KFREE
+#undef KMALLOC
+
+/* call this to initialise jnode hash table */
+int jnodes_tree_init(reiser4_tree * tree /* tree to initialise jnodes for */ )
+{
+       assert("nikita-2359", tree != NULL);
+       return j_hash_init(&tree->jhash_table, 16384);
+}
+
+/* call this to destroy jnode hash table. This is called during umount. */
+int jnodes_tree_done(reiser4_tree * tree /* tree to destroy jnodes for */ )
+{
+       j_hash_table *jtable;
+       jnode *node;
+       jnode *next;
+
+       assert("nikita-2360", tree != NULL);
+
+       /*
+        * Scan hash table and free all jnodes.
+        */
+       jtable = &tree->jhash_table;
+       if (jtable->_table) {
+               for_all_in_htable(jtable, j, node, next) {
+                       assert("nikita-2361", !atomic_read(&node->x_count));
+                       jdrop(node);
+               }
+
+               j_hash_done(&tree->jhash_table);
+       }
+       return 0;
+}
+
+/**
+ * init_jnodes - create jnode cache
+ *
+ * Initializes slab cache jnodes. It is part of reiser4 module initialization.
+ */
+int init_jnodes(void)
+{
+       assert("umka-168", _jnode_slab == NULL);
+
+       _jnode_slab = kmem_cache_create("jnode", sizeof(jnode), 0,
+                                       SLAB_HWCACHE_ALIGN |
+                                       SLAB_RECLAIM_ACCOUNT, NULL, NULL);
+       if (_jnode_slab == NULL)
+               return RETERR(-ENOMEM);
+
+       return 0;
+}
+
+/**
+ * done_znodes - delete znode cache
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void done_jnodes(void)
+{
+       destroy_reiser4_cache(&_jnode_slab);
+}
+
+/* Initialize a jnode. */
+void jnode_init(jnode * node, reiser4_tree * tree, jnode_type type)
+{
+       assert("umka-175", node != NULL);
+
+       memset(node, 0, sizeof(jnode));
+       ON_DEBUG(node->magic = JMAGIC);
+       jnode_set_type(node, type);
+       atomic_set(&node->d_count, 0);
+       atomic_set(&node->x_count, 0);
+       spin_lock_init(&node->guard);
+       spin_lock_init(&node->load);
+       node->atom = NULL;
+       node->tree = tree;
+       INIT_LIST_HEAD(&node->capture_link);
+
+       ASSIGN_NODE_LIST(node, NOT_CAPTURED);
+
+       INIT_RCU_HEAD(&node->rcu);
+
+#if REISER4_DEBUG
+       {
+               reiser4_super_info_data *sbinfo;
+
+               sbinfo = get_super_private(tree->super);
+               spin_lock_irq(&sbinfo->all_guard);
+               list_add(&node->jnodes, &sbinfo->all_jnodes);
+               spin_unlock_irq(&sbinfo->all_guard);
+       }
+#endif
+}
+
+#if REISER4_DEBUG
+/*
+ * Remove jnode from ->all_jnodes list.
+ */
+static void jnode_done(jnode * node, reiser4_tree * tree)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = get_super_private(tree->super);
+
+       spin_lock_irq(&sbinfo->all_guard);
+       assert("nikita-2422", !list_empty(&node->jnodes));
+       list_del_init(&node->jnodes);
+       spin_unlock_irq(&sbinfo->all_guard);
+}
+#endif
+
+/* return already existing jnode of page */
+jnode *jnode_by_page(struct page *pg)
+{
+       assert("nikita-2066", pg != NULL);
+       assert("nikita-2400", PageLocked(pg));
+       assert("nikita-2068", PagePrivate(pg));
+       assert("nikita-2067", jprivate(pg) != NULL);
+       return jprivate(pg);
+}
+
+/* exported functions to allocate/free jnode objects outside this file */
+jnode *jalloc(void)
+{
+       jnode *jal = kmem_cache_alloc(_jnode_slab, reiser4_ctx_gfp_mask_get());
+       return jal;
+}
+
+/* return jnode back to the slab allocator */
+inline void jfree(jnode * node)
+{
+       assert("zam-449", node != NULL);
+
+       assert("nikita-2663", (list_empty_careful(&node->capture_link) &&
+                              NODE_LIST(node) == NOT_CAPTURED));
+       assert("nikita-3222", list_empty(&node->jnodes));
+       assert("nikita-3221", jnode_page(node) == NULL);
+
+       /* not yet phash_jnode_destroy(node); */
+
+       kmem_cache_free(_jnode_slab, node);
+}
+
+/*
+ * This function is supplied as RCU callback. It actually frees jnode when
+ * last reference to it is gone.
+ */
+static void jnode_free_actor(struct rcu_head *head)
+{
+       jnode *node;
+       jnode_type jtype;
+
+       node = container_of(head, jnode, rcu);
+       jtype = jnode_get_type(node);
+
+       ON_DEBUG(jnode_done(node, jnode_get_tree(node)));
+
+       switch (jtype) {
+       case JNODE_IO_HEAD:
+       case JNODE_BITMAP:
+       case JNODE_UNFORMATTED_BLOCK:
+               jfree(node);
+               break;
+       case JNODE_FORMATTED_BLOCK:
+               zfree(JZNODE(node));
+               break;
+       case JNODE_INODE:
+       default:
+               wrong_return_value("nikita-3197", "Wrong jnode type");
+       }
+}
+
+/*
+ * Free a jnode. Post a callback to be executed later through RCU when all
+ * references to @node are released.
+ */
+static inline void jnode_free(jnode * node, jnode_type jtype)
+{
+       if (jtype != JNODE_INODE) {
+               /*assert("nikita-3219", list_empty(&node->rcu.list)); */
+               call_rcu(&node->rcu, jnode_free_actor);
+       } else
+               jnode_list_remove(node);
+}
+
+/* allocate new unformatted jnode */
+static jnode *jnew_unformatted(void)
+{
+       jnode *jal;
+
+       jal = jalloc();
+       if (jal == NULL)
+               return NULL;
+
+       jnode_init(jal, current_tree, JNODE_UNFORMATTED_BLOCK);
+       jal->key.j.mapping = NULL;
+       jal->key.j.index = (unsigned long)-1;
+       jal->key.j.objectid = 0;
+       return jal;
+}
+
+/* look for jnode with given mapping and offset within hash table */
+jnode *jlookup(reiser4_tree * tree, oid_t objectid, unsigned long index)
+{
+       jnode_key_t jkey;
+       jnode *node;
+
+       assert("nikita-2353", tree != NULL);
+
+       jkey.objectid = objectid;
+       jkey.index = index;
+
+       /*
+        * hash table is _not_ protected by any lock during lookups. All we
+        * have to do is to disable preemption to keep RCU happy.
+        */
+
+       rcu_read_lock();
+       node = j_hash_find(&tree->jhash_table, &jkey);
+       if (node != NULL) {
+               /* protect @node from recycling */
+               jref(node);
+               assert("nikita-2955", jnode_invariant(node, 0, 0));
+               node = jnode_rip_check(tree, node);
+       }
+       rcu_read_unlock();
+       return node;
+}
+
+/* per inode radix tree of jnodes is protected by tree's read write spin lock */
+static jnode *jfind_nolock(struct address_space *mapping, unsigned long index)
+{
+       assert("vs-1694", mapping->host != NULL);
+
+       return radix_tree_lookup(jnode_tree_by_inode(mapping->host), index);
+}
+
+jnode *jfind(struct address_space * mapping, unsigned long index)
+{
+       reiser4_tree *tree;
+       jnode *node;
+
+       assert("vs-1694", mapping->host != NULL);
+       tree = reiser4_tree_by_inode(mapping->host);
+
+       read_lock_tree(tree);
+       node = jfind_nolock(mapping, index);
+       if (node != NULL)
+               jref(node);
+       read_unlock_tree(tree);
+       return node;
+}
+
+static void inode_attach_jnode(jnode * node)
+{
+       struct inode *inode;
+       reiser4_inode *info;
+       struct radix_tree_root *rtree;
+
+       assert_rw_write_locked(&(jnode_get_tree(node)->tree_lock));
+       assert("zam-1043", node->key.j.mapping != NULL);
+       inode = node->key.j.mapping->host;
+       info = reiser4_inode_data(inode);
+       rtree = jnode_tree_by_reiser4_inode(info);
+       if (rtree->rnode == NULL) {
+               /* prevent inode from being pruned when it has jnodes attached
+                  to it */
+               write_lock_irq(&inode->i_data.tree_lock);
+               inode->i_data.nrpages++;
+               write_unlock_irq(&inode->i_data.tree_lock);
+       }
+       assert("zam-1049", equi(rtree->rnode != NULL, info->nr_jnodes != 0));
+       check_me("zam-1045",
+                !radix_tree_insert(rtree, node->key.j.index, node));
+       ON_DEBUG(info->nr_jnodes++);
+}
+
+static void inode_detach_jnode(jnode * node)
+{
+       struct inode *inode;
+       reiser4_inode *info;
+       struct radix_tree_root *rtree;
+
+       assert_rw_write_locked(&(jnode_get_tree(node)->tree_lock));
+       assert("zam-1044", node->key.j.mapping != NULL);
+       inode = node->key.j.mapping->host;
+       info = reiser4_inode_data(inode);
+       rtree = jnode_tree_by_reiser4_inode(info);
+
+       assert("zam-1051", info->nr_jnodes != 0);
+       assert("zam-1052", rtree->rnode != NULL);
+       ON_DEBUG(info->nr_jnodes--);
+
+       /* delete jnode from inode's radix tree of jnodes */
+       check_me("zam-1046", radix_tree_delete(rtree, node->key.j.index));
+       if (rtree->rnode == NULL) {
+               /* inode can be pruned now */
+               write_lock_irq(&inode->i_data.tree_lock);
+               inode->i_data.nrpages--;
+               write_unlock_irq(&inode->i_data.tree_lock);
+       }
+}
+
+/* put jnode into hash table (where they can be found by flush who does not know
+   mapping) and to inode's tree of jnodes (where they can be found (hopefully
+   faster) in places where mapping is known). Currently it is used by
+   fs/reiser4/plugin/item/extent_file_ops.c:index_extent_jnode when new jnode is
+   created */
+static void
+hash_unformatted_jnode(jnode * node, struct address_space *mapping,
+                      unsigned long index)
+{
+       j_hash_table *jtable;
+
+       assert("vs-1446", jnode_is_unformatted(node));
+       assert("vs-1442", node->key.j.mapping == 0);
+       assert("vs-1443", node->key.j.objectid == 0);
+       assert("vs-1444", node->key.j.index == (unsigned long)-1);
+       assert_rw_write_locked(&(jnode_get_tree(node)->tree_lock));
+
+       node->key.j.mapping = mapping;
+       node->key.j.objectid = get_inode_oid(mapping->host);
+       node->key.j.index = index;
+
+       jtable = &jnode_get_tree(node)->jhash_table;
+
+       /* race with some other thread inserting jnode into the hash table is
+        * impossible, because we keep the page lock. */
+       /*
+        * following assertion no longer holds because of RCU: it is possible
+        * jnode is in the hash table, but with JNODE_RIP bit set.
+        */
+       /* assert("nikita-3211", j_hash_find(jtable, &node->key.j) == NULL); */
+       j_hash_insert_rcu(jtable, node);
+       inode_attach_jnode(node);
+}
+
+static void unhash_unformatted_node_nolock(jnode * node)
+{
+       assert("vs-1683", node->key.j.mapping != NULL);
+       assert("vs-1684",
+              node->key.j.objectid ==
+              get_inode_oid(node->key.j.mapping->host));
+
+       /* remove jnode from hash-table */
+       j_hash_remove_rcu(&node->tree->jhash_table, node);
+       inode_detach_jnode(node);
+       node->key.j.mapping = NULL;
+       node->key.j.index = (unsigned long)-1;
+       node->key.j.objectid = 0;
+
+}
+
+/* remove jnode from hash table and from inode's tree of jnodes. This is used in
+   reiser4_invalidatepage and in kill_hook_extent -> truncate_inode_jnodes ->
+   reiser4_uncapture_jnode */
+void unhash_unformatted_jnode(jnode * node)
+{
+       assert("vs-1445", jnode_is_unformatted(node));
+
+       write_lock_tree(node->tree);
+       unhash_unformatted_node_nolock(node);
+       write_unlock_tree(node->tree);
+}
+
+/*
+ * search hash table for a jnode with given oid and index. If not found,
+ * allocate new jnode, insert it, and also insert into radix tree for the
+ * given inode/mapping.
+ */
+static jnode *find_get_jnode(reiser4_tree * tree,
+                            struct address_space *mapping,
+                            oid_t oid, unsigned long index)
+{
+       jnode *result;
+       jnode *shadow;
+       int preload;
+
+       result = jnew_unformatted();
+
+       if (unlikely(result == NULL))
+               return ERR_PTR(RETERR(-ENOMEM));
+
+       preload = radix_tree_preload(reiser4_ctx_gfp_mask_get());
+       if (preload != 0)
+               return ERR_PTR(preload);
+
+       write_lock_tree(tree);
+       shadow = jfind_nolock(mapping, index);
+       if (likely(shadow == NULL)) {
+               /* add new jnode to hash table and inode's radix tree of jnodes */
+               jref(result);
+               hash_unformatted_jnode(result, mapping, index);
+       } else {
+               /* jnode is found in inode's radix tree of jnodes */
+               jref(shadow);
+               jnode_free(result, JNODE_UNFORMATTED_BLOCK);
+               assert("vs-1498", shadow->key.j.mapping == mapping);
+               result = shadow;
+       }
+       write_unlock_tree(tree);
+
+       assert("nikita-2955",
+              ergo(result != NULL, jnode_invariant(result, 0, 0)));
+       radix_tree_preload_end();
+       return result;
+}
+
+/* jget() (a la zget() but for unformatted nodes). Returns (and possibly
+   creates) jnode corresponding to page @pg. jnode is attached to page and
+   inserted into jnode hash-table. */
+static jnode *do_jget(reiser4_tree * tree, struct page *pg)
+{
+       /*
+        * There are two ways to create jnode: starting with pre-existing page
+        * and without page.
+        *
+        * When page already exists, jnode is created
+        * (jnode_of_page()->do_jget()) under page lock. This is done in
+        * ->writepage(), or when capturing anonymous page dirtied through
+        * mmap.
+        *
+        * Jnode without page is created by index_extent_jnode().
+        *
+        */
+
+       jnode *result;
+       oid_t oid = get_inode_oid(pg->mapping->host);
+
+       assert("umka-176", pg != NULL);
+       assert("nikita-2394", PageLocked(pg));
+
+       result = jprivate(pg);
+       if (likely(result != NULL))
+               return jref(result);
+
+       tree = reiser4_tree_by_page(pg);
+
+       /* check hash-table first */
+       result = jfind(pg->mapping, pg->index);
+       if (unlikely(result != NULL)) {
+               spin_lock_jnode(result);
+               jnode_attach_page(result, pg);
+               spin_unlock_jnode(result);
+               result->key.j.mapping = pg->mapping;
+               return result;
+       }
+
+       /* since page is locked, jnode should be allocated with GFP_NOFS flag */
+       reiser4_ctx_gfp_mask_force(GFP_NOFS);
+       result = find_get_jnode(tree, pg->mapping, oid, pg->index);
+       if (unlikely(IS_ERR(result)))
+               return result;
+       /* attach jnode to page */
+       spin_lock_jnode(result);
+       jnode_attach_page(result, pg);
+       spin_unlock_jnode(result);
+       return result;
+}
+
+/*
+ * return jnode for @pg, creating it if necessary.
+ */
+jnode *jnode_of_page(struct page * pg)
+{
+       jnode *result;
+
+       assert("umka-176", pg != NULL);
+       assert("nikita-2394", PageLocked(pg));
+
+       result = do_jget(reiser4_tree_by_page(pg), pg);
+
+       if (REISER4_DEBUG && !IS_ERR(result)) {
+               assert("nikita-3210", result == jprivate(pg));
+               assert("nikita-2046", jnode_page(jprivate(pg)) == pg);
+               if (jnode_is_unformatted(jprivate(pg))) {
+                       assert("nikita-2364",
+                              jprivate(pg)->key.j.index == pg->index);
+                       assert("nikita-2367",
+                              jprivate(pg)->key.j.mapping == pg->mapping);
+                       assert("nikita-2365",
+                              jprivate(pg)->key.j.objectid ==
+                              get_inode_oid(pg->mapping->host));
+                       assert("vs-1200",
+                              jprivate(pg)->key.j.objectid ==
+                              pg->mapping->host->i_ino);
+                       assert("nikita-2356",
+                              jnode_is_unformatted(jnode_by_page(pg)));
+               }
+               assert("nikita-2956", jnode_invariant(jprivate(pg), 0, 0));
+       }
+       return result;
+}
+
+/* attach page to jnode: set ->pg pointer in jnode, and ->private one in the
+ * page.*/
+void jnode_attach_page(jnode * node, struct page *pg)
+{
+       assert("nikita-2060", node != NULL);
+       assert("nikita-2061", pg != NULL);
+
+       assert("nikita-2050", jprivate(pg) == 0ul);
+       assert("nikita-2393", !PagePrivate(pg));
+       assert("vs-1741", node->pg == NULL);
+
+       assert("nikita-2396", PageLocked(pg));
+       assert_spin_locked(&(node->guard));
+
+       page_cache_get(pg);
+       set_page_private(pg, (unsigned long)node);
+       node->pg = pg;
+       SetPagePrivate(pg);
+}
+
+/* Dual to jnode_attach_page: break a binding between page and jnode */
+void page_clear_jnode(struct page *page, jnode * node)
+{
+       assert("nikita-2424", page != NULL);
+       assert("nikita-2425", PageLocked(page));
+       assert("nikita-2426", node != NULL);
+       assert_spin_locked(&(node->guard));
+       assert("nikita-2428", PagePrivate(page));
+
+       assert("nikita-3551", !PageWriteback(page));
+
+       JF_CLR(node, JNODE_PARSED);
+       set_page_private(page, 0ul);
+       ClearPagePrivate(page);
+       node->pg = NULL;
+       page_cache_release(page);
+}
+
+#if 0
+/* it is only used in one place to handle error */
+void
+page_detach_jnode(struct page *page, struct address_space *mapping,
+                 unsigned long index)
+{
+       assert("nikita-2395", page != NULL);
+
+       lock_page(page);
+       if ((page->mapping == mapping) && (page->index == index)
+           && PagePrivate(page)) {
+               jnode *node;
+
+               node = jprivate(page);
+               spin_lock_jnode(node);
+               page_clear_jnode(page, node);
+               spin_unlock_jnode(node);
+       }
+       unlock_page(page);
+}
+#endif  /*  0  */
+
+/* return @node page locked.
+
+   Locking ordering requires that one first takes page lock and afterwards
+   spin lock on node attached to this page. Sometimes it is necessary to go in
+   the opposite direction. This is done through standard trylock-and-release
+   loop.
+*/
+static struct page *jnode_lock_page(jnode * node)
+{
+       struct page *page;
+
+       assert("nikita-2052", node != NULL);
+       assert("nikita-2401", LOCK_CNT_NIL(spin_locked_jnode));
+
+       while (1) {
+
+               spin_lock_jnode(node);
+               page = jnode_page(node);
+               if (page == NULL) {
+                       break;
+               }
+
+               /* no need to page_cache_get( page ) here, because page cannot
+                  be evicted from memory without detaching it from jnode and
+                  this requires spin lock on jnode that we already hold.
+                */
+               if (!TestSetPageLocked(page)) {
+                       /* We won a lock on jnode page, proceed. */
+                       break;
+               }
+
+               /* Page is locked by someone else. */
+               page_cache_get(page);
+               spin_unlock_jnode(node);
+               wait_on_page_locked(page);
+               /* it is possible that page was detached from jnode and
+                  returned to the free pool, or re-assigned while we were
+                  waiting on locked bit. This will be rechecked on the next
+                  loop iteration.
+                */
+               page_cache_release(page);
+
+               /* try again */
+       }
+       return page;
+}
+
+/*
+ * is JNODE_PARSED bit is not set, call ->parse() method of jnode, to verify
+ * validness of jnode content.
+ */
+static inline int jparse(jnode * node)
+{
+       int result;
+
+       assert("nikita-2466", node != NULL);
+
+       spin_lock_jnode(node);
+       if (likely(!jnode_is_parsed(node))) {
+               result = jnode_ops(node)->parse(node);
+               if (likely(result == 0))
+                       JF_SET(node, JNODE_PARSED);
+       } else
+               result = 0;
+       spin_unlock_jnode(node);
+       return result;
+}
+
+/* Lock a page attached to jnode, create and attach page to jnode if it had no
+ * one. */
+static struct page *jnode_get_page_locked(jnode * node, gfp_t gfp_flags)
+{
+       struct page *page;
+
+       spin_lock_jnode(node);
+       page = jnode_page(node);
+
+       if (page == NULL) {
+               spin_unlock_jnode(node);
+               page = find_or_create_page(jnode_get_mapping(node),
+                                          jnode_get_index(node), gfp_flags);
+               if (page == NULL)
+                       return ERR_PTR(RETERR(-ENOMEM));
+       } else {
+               if (!TestSetPageLocked(page)) {
+                       spin_unlock_jnode(node);
+                       return page;
+               }
+               page_cache_get(page);
+               spin_unlock_jnode(node);
+               lock_page(page);
+               assert("nikita-3134", page->mapping == jnode_get_mapping(node));
+       }
+
+       spin_lock_jnode(node);
+       if (!jnode_page(node))
+               jnode_attach_page(node, page);
+       spin_unlock_jnode(node);
+
+       page_cache_release(page);
+       assert("zam-894", jnode_page(node) == page);
+       return page;
+}
+
+/* Start read operation for jnode's page if page is not up-to-date. */
+static int jnode_start_read(jnode * node, struct page *page)
+{
+       assert("zam-893", PageLocked(page));
+
+       if (PageUptodate(page)) {
+               unlock_page(page);
+               return 0;
+       }
+       return reiser4_page_io(page, node, READ, reiser4_ctx_gfp_mask_get());
+}
+
+#if REISER4_DEBUG
+static void check_jload(jnode * node, struct page *page)
+{
+       if (jnode_is_znode(node)) {
+               node40_header *nh;
+               znode *z;
+
+               z = JZNODE(node);
+               if (znode_is_any_locked(z)) {
+                       nh = (node40_header *) kmap(page);
+                       /* this only works for node40-only file systems. For
+                        * debugging. */
+                       assert("nikita-3253",
+                              z->nr_items == le16_to_cpu(get_unaligned(&nh->nr_items)));
+                       kunmap(page);
+               }
+               assert("nikita-3565", znode_invariant(z));
+       }
+}
+#else
+#define check_jload(node, page) noop
+#endif
+
+/* prefetch jnode to speed up next call to jload. Call this when you are going
+ * to call jload() shortly. This will bring appropriate portion of jnode into
+ * CPU cache. */
+void jload_prefetch(jnode * node)
+{
+       prefetchw(&node->x_count);
+}
+
+/* load jnode's data into memory */
+int jload_gfp(jnode * node /* node to load */ ,
+             gfp_t gfp_flags /* allocation flags */ ,
+             int do_kmap /* true if page should be kmapped */ )
+{
+       struct page *page;
+       int result = 0;
+       int parsed;
+
+       assert("nikita-3010", reiser4_schedulable());
+
+       prefetchw(&node->pg);
+
+       /* taking d-reference implies taking x-reference. */
+       jref(node);
+
+       /*
+        * acquiring d-reference to @jnode and check for JNODE_PARSED bit
+        * should be atomic, otherwise there is a race against
+        * reiser4_releasepage().
+        */
+       spin_lock(&(node->load));
+       add_d_ref(node);
+       parsed = jnode_is_parsed(node);
+       spin_unlock(&(node->load));
+
+       if (unlikely(!parsed)) {
+               page = jnode_get_page_locked(node, gfp_flags);
+               if (unlikely(IS_ERR(page))) {
+                       result = PTR_ERR(page);
+                       goto failed;
+               }
+
+               result = jnode_start_read(node, page);
+               if (unlikely(result != 0))
+                       goto failed;
+
+               wait_on_page_locked(page);
+               if (unlikely(!PageUptodate(page))) {
+                       result = RETERR(-EIO);
+                       goto failed;
+               }
+
+               if (do_kmap)
+                       node->data = kmap(page);
+
+               result = jparse(node);
+               if (unlikely(result != 0)) {
+                       if (do_kmap)
+                               kunmap(page);
+                       goto failed;
+               }
+               check_jload(node, page);
+       } else {
+               page = jnode_page(node);
+               check_jload(node, page);
+               if (do_kmap)
+                       node->data = kmap(page);
+       }
+
+       if (!is_writeout_mode())
+               /* We do not mark pages active if jload is called as a part of
+                * jnode_flush() or reiser4_write_logs().  Both jnode_flush()
+                * and write_logs() add no value to cached data, there is no
+                * sense to mark pages as active when they go to disk, it just
+                * confuses vm scanning routines because clean page could be
+                * moved out from inactive list as a result of this
+                * mark_page_accessed() call. */
+               mark_page_accessed(page);
+
+       return 0;
+
+      failed:
+       jrelse_tail(node);
+       return result;
+
+}
+
+/* start asynchronous reading for given jnode's page. */
+int jstartio(jnode * node)
+{
+       struct page *page;
+
+       page = jnode_get_page_locked(node, reiser4_ctx_gfp_mask_get());
+       if (IS_ERR(page))
+               return PTR_ERR(page);
+
+       return jnode_start_read(node, page);
+}
+
+/* Initialize a node by calling appropriate plugin instead of reading
+ * node from disk as in jload(). */
+int jinit_new(jnode * node, gfp_t gfp_flags)
+{
+       struct page *page;
+       int result;
+
+       jref(node);
+       add_d_ref(node);
+
+       page = jnode_get_page_locked(node, gfp_flags);
+       if (IS_ERR(page)) {
+               result = PTR_ERR(page);
+               goto failed;
+       }
+
+       SetPageUptodate(page);
+       unlock_page(page);
+
+       node->data = kmap(page);
+
+       if (!jnode_is_parsed(node)) {
+               jnode_plugin *jplug = jnode_ops(node);
+               spin_lock_jnode(node);
+               result = jplug->init(node);
+               spin_unlock_jnode(node);
+               if (result) {
+                       kunmap(page);
+                       goto failed;
+               }
+               JF_SET(node, JNODE_PARSED);
+       }
+
+       return 0;
+
+      failed:
+       jrelse(node);
+       return result;
+}
+
+/* release a reference to jnode acquired by jload(), decrement ->d_count */
+void jrelse_tail(jnode * node /* jnode to release references to */ )
+{
+       assert("nikita-489", atomic_read(&node->d_count) > 0);
+       atomic_dec(&node->d_count);
+       /* release reference acquired in jload_gfp() or jinit_new() */
+       jput(node);
+       if (jnode_is_unformatted(node) || jnode_is_znode(node))
+               LOCK_CNT_DEC(d_refs);
+}
+
+/* drop reference to node data. When last reference is dropped, data are
+   unloaded. */
+void jrelse(jnode * node /* jnode to release references to */ )
+{
+       struct page *page;
+
+       assert("nikita-487", node != NULL);
+       assert_spin_not_locked(&(node->guard));
+
+       page = jnode_page(node);
+       if (likely(page != NULL)) {
+               /*
+                * it is safe not to lock jnode here, because at this point
+                * @node->d_count is greater than zero (if jrelse() is used
+                * correctly, that is). JNODE_PARSED may be not set yet, if,
+                * for example, we got here as a result of error handling path
+                * in jload(). Anyway, page cannot be detached by
+                * reiser4_releasepage(). truncate will invalidate page
+                * regardless, but this should not be a problem.
+                */
+               kunmap(page);
+       }
+       jrelse_tail(node);
+}
+
+/* called from jput() to wait for io completion */
+static void jnode_finish_io(jnode * node)
+{
+       struct page *page;
+
+       assert("nikita-2922", node != NULL);
+
+       spin_lock_jnode(node);
+       page = jnode_page(node);
+       if (page != NULL) {
+               page_cache_get(page);
+               spin_unlock_jnode(node);
+               wait_on_page_writeback(page);
+               page_cache_release(page);
+       } else
+               spin_unlock_jnode(node);
+}
+
+/*
+ * This is called by jput() when last reference to jnode is released. This is
+ * separate function, because we want fast path of jput() to be inline and,
+ * therefore, small.
+ */
+void jput_final(jnode * node)
+{
+       int r_i_p;
+
+       /* A fast check for keeping node in cache. We always keep node in cache
+        * if its page is present and node was not marked for deletion */
+       if (jnode_page(node) != NULL && !JF_ISSET(node, JNODE_HEARD_BANSHEE)) {
+               rcu_read_unlock();
+               return;
+       }
+       assert("edward-1432", node->page_count == 0);
+
+       r_i_p = !JF_TEST_AND_SET(node, JNODE_RIP);
+       /*
+        * if r_i_p is true, we were first to set JNODE_RIP on this node. In
+        * this case it is safe to access node after unlock.
+        */
+       rcu_read_unlock();
+       if (r_i_p) {
+               jnode_finish_io(node);
+               if (JF_ISSET(node, JNODE_HEARD_BANSHEE))
+                       /* node is removed from the tree. */
+                       jdelete(node);
+               else
+                       jnode_try_drop(node);
+       }
+       /* if !r_i_p some other thread is already killing it */
+}
+
+int jwait_io(jnode * node, int rw)
+{
+       struct page *page;
+       int result;
+
+       assert("zam-447", node != NULL);
+       assert("zam-448", jnode_page(node) != NULL);
+
+       page = jnode_page(node);
+
+       result = 0;
+       if (rw == READ) {
+               wait_on_page_locked(page);
+       } else {
+               assert("nikita-2227", rw == WRITE);
+               wait_on_page_writeback(page);
+       }
+       if (PageError(page))
+               result = RETERR(-EIO);
+
+       return result;
+}
+
+/*
+ * jnode types and plugins.
+ *
+ * jnode by itself is a "base type". There are several different jnode
+ * flavors, called "jnode types" (see jnode_type for a list). Sometimes code
+ * has to do different things based on jnode type. In the standard reiser4 way
+ * this is done by having jnode plugin (see fs/reiser4/plugin.h:jnode_plugin).
+ *
+ * Functions below deal with jnode types and define methods of jnode plugin.
+ *
+ */
+
+/* set jnode type. This is done during jnode initialization. */
+static void jnode_set_type(jnode * node, jnode_type type)
+{
+       static unsigned long type_to_mask[] = {
+               [JNODE_UNFORMATTED_BLOCK] = 1,
+               [JNODE_FORMATTED_BLOCK] = 0,
+               [JNODE_BITMAP] = 2,
+               [JNODE_IO_HEAD] = 6,
+               [JNODE_INODE] = 4
+       };
+
+       assert("zam-647", type < LAST_JNODE_TYPE);
+       assert("nikita-2815", !jnode_is_loaded(node));
+       assert("nikita-3386", node->state == 0);
+
+       node->state |= (type_to_mask[type] << JNODE_TYPE_1);
+}
+
+/* ->init() method of jnode plugin for jnodes that don't require plugin
+ * specific initialization. */
+static int init_noinit(jnode * node UNUSED_ARG)
+{
+       return 0;
+}
+
+/* ->parse() method of jnode plugin for jnodes that don't require plugin
+ * specific pasring. */
+static int parse_noparse(jnode * node UNUSED_ARG)
+{
+       return 0;
+}
+
+/* ->mapping() method for unformatted jnode */
+struct address_space *mapping_jnode(const jnode * node)
+{
+       struct address_space *map;
+
+       assert("nikita-2713", node != NULL);
+
+       /* mapping is stored in jnode */
+
+       map = node->key.j.mapping;
+       assert("nikita-2714", map != NULL);
+       assert("nikita-2897", is_reiser4_inode(map->host));
+       assert("nikita-2715", get_inode_oid(map->host) == node->key.j.objectid);
+       return map;
+}
+
+/* ->index() method for unformatted jnodes */
+unsigned long index_jnode(const jnode * node)
+{
+       /* index is stored in jnode */
+       return node->key.j.index;
+}
+
+/* ->remove() method for unformatted jnodes */
+static inline void remove_jnode(jnode * node, reiser4_tree * tree)
+{
+       /* remove jnode from hash table and radix tree */
+       if (node->key.j.mapping)
+               unhash_unformatted_node_nolock(node);
+}
+
+/* ->mapping() method for znodes */
+static struct address_space *mapping_znode(const jnode * node)
+{
+       /* all znodes belong to fake inode */
+       return reiser4_get_super_fake(jnode_get_tree(node)->super)->i_mapping;
+}
+
+/* ->index() method for znodes */
+static unsigned long index_znode(const jnode * node)
+{
+       unsigned long addr;
+       assert("nikita-3317", (1 << znode_shift_order) < sizeof(znode));
+
+       /* index of znode is just its address (shifted) */
+       addr = (unsigned long)node;
+       return (addr - PAGE_OFFSET) >> znode_shift_order;
+}
+
+/* ->mapping() method for bitmap jnode */
+static struct address_space *mapping_bitmap(const jnode * node)
+{
+       /* all bitmap blocks belong to special bitmap inode */
+       return get_super_private(jnode_get_tree(node)->super)->bitmap->
+           i_mapping;
+}
+
+/* ->index() method for jnodes that are indexed by address */
+static unsigned long index_is_address(const jnode * node)
+{
+       unsigned long ind;
+
+       ind = (unsigned long)node;
+       return ind - PAGE_OFFSET;
+}
+
+/* resolve race with jput */
+jnode *jnode_rip_sync(reiser4_tree *tree, jnode *node)
+{
+       /*
+        * This is used as part of RCU-based jnode handling.
+        *
+        * jlookup(), zlook(), zget(), and cbk_cache_scan_slots() have to work
+        * with unreferenced jnodes (ones with ->x_count == 0). Hash table is
+        * not protected during this, so concurrent thread may execute
+        * zget-set-HEARD_BANSHEE-zput, or somehow else cause jnode to be
+        * freed in jput_final(). To avoid such races, jput_final() sets
+        * JNODE_RIP on jnode (under tree lock). All places that work with
+        * unreferenced jnodes call this function. It checks for JNODE_RIP bit
+        * (first without taking tree lock), and if this bit is set, released
+        * reference acquired by the current thread and returns NULL.
+        *
+        * As a result, if jnode is being concurrently freed, NULL is returned
+        * and caller should pretend that jnode wasn't found in the first
+        * place.
+        *
+        * Otherwise it's safe to release "rcu-read-lock" and continue with
+        * jnode.
+        */
+       if (unlikely(JF_ISSET(node, JNODE_RIP))) {
+               read_lock_tree(tree);
+               if (JF_ISSET(node, JNODE_RIP)) {
+                       dec_x_ref(node);
+                       node = NULL;
+               }
+               read_unlock_tree(tree);
+       }
+       return node;
+}
+
+reiser4_key *jnode_build_key(const jnode * node, reiser4_key * key)
+{
+       struct inode *inode;
+       item_plugin *iplug;
+       loff_t off;
+
+       assert("nikita-3092", node != NULL);
+       assert("nikita-3093", key != NULL);
+       assert("nikita-3094", jnode_is_unformatted(node));
+
+       off = ((loff_t) index_jnode(node)) << PAGE_CACHE_SHIFT;
+       inode = mapping_jnode(node)->host;
+
+       if (node->parent_item_id != 0)
+               iplug = item_plugin_by_id(node->parent_item_id);
+       else
+               iplug = NULL;
+
+       if (iplug != NULL && iplug->f.key_by_offset)
+               iplug->f.key_by_offset(inode, off, key);
+       else {
+               file_plugin *fplug;
+
+               fplug = inode_file_plugin(inode);
+               assert("zam-1007", fplug != NULL);
+               assert("zam-1008", fplug->key_by_inode != NULL);
+
+               fplug->key_by_inode(inode, off, key);
+       }
+
+       return key;
+}
+
+/* ->parse() method for formatted nodes */
+static int parse_znode(jnode * node)
+{
+       return zparse(JZNODE(node));
+}
+
+/* ->delete() method for formatted nodes */
+static void delete_znode(jnode * node, reiser4_tree * tree)
+{
+       znode *z;
+
+       assert_rw_write_locked(&(tree->tree_lock));
+       assert("vs-898", JF_ISSET(node, JNODE_HEARD_BANSHEE));
+
+       z = JZNODE(node);
+       assert("vs-899", z->c_count == 0);
+
+       /* delete znode from sibling list. */
+       sibling_list_remove(z);
+
+       znode_remove(z, tree);
+}
+
+/* ->remove() method for formatted nodes */
+static int remove_znode(jnode * node, reiser4_tree * tree)
+{
+       znode *z;
+
+       assert_rw_write_locked(&(tree->tree_lock));
+       z = JZNODE(node);
+
+       if (z->c_count == 0) {
+               /* detach znode from sibling list. */
+               sibling_list_drop(z);
+               /* this is called with tree spin-lock held, so call
+                  znode_remove() directly (rather than znode_lock_remove()). */
+               znode_remove(z, tree);
+               return 0;
+       }
+       return RETERR(-EBUSY);
+}
+
+/* ->init() method for formatted nodes */
+static int init_znode(jnode * node)
+{
+       znode *z;
+
+       z = JZNODE(node);
+       /* call node plugin to do actual initialization */
+       return z->nplug->init(z);
+}
+
+/* ->clone() method for formatted nodes */
+static jnode *clone_formatted(jnode * node)
+{
+       znode *clone;
+
+       assert("vs-1430", jnode_is_znode(node));
+       clone = zalloc(reiser4_ctx_gfp_mask_get());
+       if (clone == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+       zinit(clone, NULL, current_tree);
+       jnode_set_block(ZJNODE(clone), jnode_get_block(node));
+       /* ZJNODE(clone)->key.z is not initialized */
+       clone->level = JZNODE(node)->level;
+
+       return ZJNODE(clone);
+}
+
+/* jplug->clone for unformatted nodes */
+static jnode *clone_unformatted(jnode * node)
+{
+       jnode *clone;
+
+       assert("vs-1431", jnode_is_unformatted(node));
+       clone = jalloc();
+       if (clone == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+
+       jnode_init(clone, current_tree, JNODE_UNFORMATTED_BLOCK);
+       jnode_set_block(clone, jnode_get_block(node));
+
+       return clone;
+
+}
+
+/*
+ * Setup jnode plugin methods for various jnode types.
+ */
+jnode_plugin jnode_plugins[LAST_JNODE_TYPE] = {
+       [JNODE_UNFORMATTED_BLOCK] = {
+               .h = {
+                       .type_id = REISER4_JNODE_PLUGIN_TYPE,
+                       .id = JNODE_UNFORMATTED_BLOCK,
+                       .pops = NULL,
+                       .label = "unformatted",
+                       .desc = "unformatted node",
+                       .linkage = {NULL, NULL}
+               },
+               .init = init_noinit,
+               .parse = parse_noparse,
+               .mapping = mapping_jnode,
+               .index = index_jnode,
+               .clone = clone_unformatted
+       },
+       [JNODE_FORMATTED_BLOCK] = {
+               .h = {
+                       .type_id = REISER4_JNODE_PLUGIN_TYPE,
+                       .id = JNODE_FORMATTED_BLOCK,
+                       .pops = NULL,
+                       .label = "formatted",
+                       .desc = "formatted tree node",
+                       .linkage = {NULL, NULL}
+               },
+               .init = init_znode,
+               .parse = parse_znode,
+               .mapping = mapping_znode,
+               .index = index_znode,
+               .clone = clone_formatted
+       },
+       [JNODE_BITMAP] = {
+               .h = {
+                       .type_id = REISER4_JNODE_PLUGIN_TYPE,
+                       .id = JNODE_BITMAP,
+                       .pops = NULL,
+                       .label = "bitmap",
+                       .desc = "bitmap node",
+                       .linkage = {NULL, NULL}
+               },
+               .init = init_noinit,
+               .parse = parse_noparse,
+               .mapping = mapping_bitmap,
+               .index = index_is_address,
+               .clone = NULL
+       },
+       [JNODE_IO_HEAD] = {
+               .h = {
+                       .type_id = REISER4_JNODE_PLUGIN_TYPE,
+                       .id = JNODE_IO_HEAD,
+                       .pops = NULL,
+                       .label = "io head",
+                       .desc = "io head",
+                       .linkage = {NULL, NULL}
+               },
+               .init = init_noinit,
+               .parse = parse_noparse,
+               .mapping = mapping_bitmap,
+               .index = index_is_address,
+               .clone = NULL
+       },
+       [JNODE_INODE] = {
+               .h = {
+                       .type_id = REISER4_JNODE_PLUGIN_TYPE,
+                       .id = JNODE_INODE,
+                       .pops = NULL,
+                       .label = "inode",
+                       .desc = "inode's builtin jnode",
+                       .linkage = {NULL, NULL}
+               },
+               .init = NULL,
+               .parse = NULL,
+               .mapping = NULL,
+               .index = NULL,
+               .clone = NULL
+       }
+};
+
+/*
+ * jnode destruction.
+ *
+ * Thread may use a jnode after it acquired a reference to it. References are
+ * counted in ->x_count field. Reference protects jnode from being
+ * recycled. This is different from protecting jnode data (that are stored in
+ * jnode page) from being evicted from memory. Data are protected by jload()
+ * and released by jrelse().
+ *
+ * If thread already possesses a reference to the jnode it can acquire another
+ * one through jref(). Initial reference is obtained (usually) by locating
+ * jnode in some indexing structure that depends on jnode type: formatted
+ * nodes are kept in global hash table, where they are indexed by block
+ * number, and also in the cbk cache. Unformatted jnodes are also kept in hash
+ * table, which is indexed by oid and offset within file, and in per-inode
+ * radix tree.
+ *
+ * Reference to jnode is released by jput(). If last reference is released,
+ * jput_final() is called. This function determines whether jnode has to be
+ * deleted (this happens when corresponding node is removed from the file
+ * system, jnode is marked with JNODE_HEARD_BANSHEE bit in this case), or it
+ * should be just "removed" (deleted from memory).
+ *
+ * Jnode destruction is signally delicate dance because of locking and RCU.
+ */
+
+/*
+ * Returns true if jnode cannot be removed right now. This check is called
+ * under tree lock. If it returns true, jnode is irrevocably committed to be
+ * deleted/removed.
+ */
+static inline int jnode_is_busy(const jnode * node, jnode_type jtype)
+{
+       /* if other thread managed to acquire a reference to this jnode, don't
+        * free it. */
+       if (atomic_read(&node->x_count) > 0)
+               return 1;
+       /* also, don't free znode that has children in memory */
+       if (jtype == JNODE_FORMATTED_BLOCK && JZNODE(node)->c_count > 0)
+               return 1;
+       return 0;
+}
+
+/*
+ * this is called as part of removing jnode. Based on jnode type, call
+ * corresponding function that removes jnode from indices and returns it back
+ * to the appropriate slab (through RCU).
+ */
+static inline void
+jnode_remove(jnode * node, jnode_type jtype, reiser4_tree * tree)
+{
+       switch (jtype) {
+       case JNODE_UNFORMATTED_BLOCK:
+               remove_jnode(node, tree);
+               break;
+       case JNODE_IO_HEAD:
+       case JNODE_BITMAP:
+               break;
+       case JNODE_INODE:
+               break;
+       case JNODE_FORMATTED_BLOCK:
+               remove_znode(node, tree);
+               break;
+       default:
+               wrong_return_value("nikita-3196", "Wrong jnode type");
+       }
+}
+
+/*
+ * this is called as part of deleting jnode. Based on jnode type, call
+ * corresponding function that removes jnode from indices and returns it back
+ * to the appropriate slab (through RCU).
+ *
+ * This differs from jnode_remove() only for formatted nodes---for them
+ * sibling list handling is different for removal and deletion.
+ */
+static inline void
+jnode_delete(jnode * node, jnode_type jtype, reiser4_tree * tree UNUSED_ARG)
+{
+       switch (jtype) {
+       case JNODE_UNFORMATTED_BLOCK:
+               remove_jnode(node, tree);
+               break;
+       case JNODE_IO_HEAD:
+       case JNODE_BITMAP:
+               break;
+       case JNODE_FORMATTED_BLOCK:
+               delete_znode(node, tree);
+               break;
+       case JNODE_INODE:
+       default:
+               wrong_return_value("nikita-3195", "Wrong jnode type");
+       }
+}
+
+#if REISER4_DEBUG
+/*
+ * remove jnode from the debugging list of all jnodes hanging off super-block.
+ */
+void jnode_list_remove(jnode * node)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = get_super_private(jnode_get_tree(node)->super);
+
+       spin_lock_irq(&sbinfo->all_guard);
+       assert("nikita-2422", !list_empty(&node->jnodes));
+       list_del_init(&node->jnodes);
+       spin_unlock_irq(&sbinfo->all_guard);
+}
+#endif
+
+/*
+ * this is called by jput_final() to remove jnode when last reference to it is
+ * released.
+ */
+static int jnode_try_drop(jnode * node)
+{
+       int result;
+       reiser4_tree *tree;
+       jnode_type jtype;
+
+       assert("nikita-2491", node != NULL);
+       assert("nikita-2583", JF_ISSET(node, JNODE_RIP));
+
+       tree = jnode_get_tree(node);
+       jtype = jnode_get_type(node);
+
+       spin_lock_jnode(node);
+       write_lock_tree(tree);
+       /*
+        * if jnode has a page---leave it alone. Memory pressure will
+        * eventually kill page and jnode.
+        */
+       if (jnode_page(node) != NULL) {
+               write_unlock_tree(tree);
+               spin_unlock_jnode(node);
+               JF_CLR(node, JNODE_RIP);
+               return RETERR(-EBUSY);
+       }
+
+       /* re-check ->x_count under tree lock. */
+       result = jnode_is_busy(node, jtype);
+       if (result == 0) {
+               assert("nikita-2582", !JF_ISSET(node, JNODE_HEARD_BANSHEE));
+               assert("jmacd-511/b", atomic_read(&node->d_count) == 0);
+
+               spin_unlock_jnode(node);
+               /* no page and no references---despatch him. */
+               jnode_remove(node, jtype, tree);
+               write_unlock_tree(tree);
+               jnode_free(node, jtype);
+       } else {
+               /* busy check failed: reference was acquired by concurrent
+                * thread. */
+               write_unlock_tree(tree);
+               spin_unlock_jnode(node);
+               JF_CLR(node, JNODE_RIP);
+       }
+       return result;
+}
+
+/* jdelete() -- Delete jnode from the tree and file system */
+static int jdelete(jnode * node /* jnode to finish with */ )
+{
+       struct page *page;
+       int result;
+       reiser4_tree *tree;
+       jnode_type jtype;
+
+       assert("nikita-467", node != NULL);
+       assert("nikita-2531", JF_ISSET(node, JNODE_RIP));
+
+       jtype = jnode_get_type(node);
+
+       page = jnode_lock_page(node);
+       assert_spin_locked(&(node->guard));
+
+       tree = jnode_get_tree(node);
+
+       write_lock_tree(tree);
+       /* re-check ->x_count under tree lock. */
+       result = jnode_is_busy(node, jtype);
+       if (likely(!result)) {
+               assert("nikita-2123", JF_ISSET(node, JNODE_HEARD_BANSHEE));
+               assert("jmacd-511", atomic_read(&node->d_count) == 0);
+
+               /* detach page */
+               if (page != NULL) {
+                       /*
+                        * FIXME this is racy against jnode_extent_write().
+                        */
+                       page_clear_jnode(page, node);
+               }
+               spin_unlock_jnode(node);
+               /* goodbye */
+               jnode_delete(node, jtype, tree);
+               write_unlock_tree(tree);
+               jnode_free(node, jtype);
+               /* @node is no longer valid pointer */
+               if (page != NULL)
+                       reiser4_drop_page(page);
+       } else {
+               /* busy check failed: reference was acquired by concurrent
+                * thread. */
+               JF_CLR(node, JNODE_RIP);
+               write_unlock_tree(tree);
+               spin_unlock_jnode(node);
+               if (page != NULL)
+                       unlock_page(page);
+       }
+       return result;
+}
+
+/* drop jnode on the floor.
+
+   Return value:
+
+    -EBUSY:  failed to drop jnode, because there are still references to it
+
+    0:       successfully dropped jnode
+
+*/
+static int jdrop_in_tree(jnode * node, reiser4_tree * tree)
+{
+       struct page *page;
+       jnode_type jtype;
+       int result;
+
+       assert("zam-602", node != NULL);
+       assert_rw_not_read_locked(&(tree->tree_lock));
+       assert_rw_not_write_locked(&(tree->tree_lock));
+       assert("nikita-2403", !JF_ISSET(node, JNODE_HEARD_BANSHEE));
+
+       jtype = jnode_get_type(node);
+
+       page = jnode_lock_page(node);
+       assert_spin_locked(&(node->guard));
+
+       write_lock_tree(tree);
+
+       /* re-check ->x_count under tree lock. */
+       result = jnode_is_busy(node, jtype);
+       if (!result) {
+               assert("nikita-2488", page == jnode_page(node));
+               assert("nikita-2533", atomic_read(&node->d_count) == 0);
+               if (page != NULL) {
+                       assert("nikita-2126", !PageDirty(page));
+                       assert("nikita-2127", PageUptodate(page));
+                       assert("nikita-2181", PageLocked(page));
+                       page_clear_jnode(page, node);
+               }
+               spin_unlock_jnode(node);
+               jnode_remove(node, jtype, tree);
+               write_unlock_tree(tree);
+               jnode_free(node, jtype);
+               if (page != NULL) {
+                       reiser4_drop_page(page);
+               }
+       } else {
+               /* busy check failed: reference was acquired by concurrent
+                * thread. */
+               JF_CLR(node, JNODE_RIP);
+               write_unlock_tree(tree);
+               spin_unlock_jnode(node);
+               if (page != NULL)
+                       unlock_page(page);
+       }
+       return result;
+}
+
+/* This function frees jnode "if possible". In particular, [dcx]_count has to
+   be 0 (where applicable).  */
+void jdrop(jnode * node)
+{
+       jdrop_in_tree(node, jnode_get_tree(node));
+}
+
+/* IO head jnode implementation; The io heads are simple j-nodes with limited
+   functionality (these j-nodes are not in any hash table) just for reading
+   from and writing to disk. */
+
+jnode *reiser4_alloc_io_head(const reiser4_block_nr * block)
+{
+       jnode *jal = jalloc();
+
+       if (jal != NULL) {
+               jnode_init(jal, current_tree, JNODE_IO_HEAD);
+               jnode_set_block(jal, block);
+       }
+
+       jref(jal);
+
+       return jal;
+}
+
+void reiser4_drop_io_head(jnode * node)
+{
+       assert("zam-648", jnode_get_type(node) == JNODE_IO_HEAD);
+
+       jput(node);
+       jdrop(node);
+}
+
+/* protect keep jnode data from reiser4_releasepage()  */
+void pin_jnode_data(jnode * node)
+{
+       assert("zam-671", jnode_page(node) != NULL);
+       page_cache_get(jnode_page(node));
+}
+
+/* make jnode data free-able again */
+void unpin_jnode_data(jnode * node)
+{
+       assert("zam-672", jnode_page(node) != NULL);
+       page_cache_release(jnode_page(node));
+}
+
+struct address_space *jnode_get_mapping(const jnode * node)
+{
+       assert("nikita-3162", node != NULL);
+       return jnode_ops(node)->mapping(node);
+}
+
+#if REISER4_DEBUG
+/* debugging aid: jnode invariant */
+int jnode_invariant_f(const jnode * node, char const **msg)
+{
+#define _ergo(ant, con)                                                \
+       ((*msg) = "{" #ant "} ergo {" #con "}", ergo((ant), (con)))
+#define _check(exp) ((*msg) = #exp, (exp))
+
+       return _check(node != NULL) &&
+           /* [jnode-queued] */
+           /* only relocated node can be queued, except that when znode
+            * is being deleted, its JNODE_RELOC bit is cleared */
+           _ergo(JF_ISSET(node, JNODE_FLUSH_QUEUED),
+                 JF_ISSET(node, JNODE_RELOC) ||
+                 JF_ISSET(node, JNODE_HEARD_BANSHEE)) &&
+           _check(node->jnodes.prev != NULL) &&
+           _check(node->jnodes.next != NULL) &&
+           /* [jnode-dirty] invariant */
+           /* dirty inode is part of atom */
+           _ergo(JF_ISSET(node, JNODE_DIRTY), node->atom != NULL) &&
+           /* [jnode-oid] invariant */
+           /* for unformatted node ->objectid and ->mapping fields are
+            * consistent */
+           _ergo(jnode_is_unformatted(node) && node->key.j.mapping != NULL,
+                 node->key.j.objectid ==
+                 get_inode_oid(node->key.j.mapping->host)) &&
+           /* [jnode-atom-valid] invariant */
+           /* node atom has valid state */
+           _ergo(node->atom != NULL, node->atom->stage != ASTAGE_INVALID) &&
+           /* [jnode-page-binding] invariant */
+           /* if node points to page, it points back to node */
+           _ergo(node->pg != NULL, jprivate(node->pg) == node) &&
+           /* [jnode-refs] invariant */
+           /* only referenced jnode can be loaded */
+           _check(atomic_read(&node->x_count) >= atomic_read(&node->d_count));
+
+}
+
+static const char *jnode_type_name(jnode_type type)
+{
+       switch (type) {
+       case JNODE_UNFORMATTED_BLOCK:
+               return "unformatted";
+       case JNODE_FORMATTED_BLOCK:
+               return "formatted";
+       case JNODE_BITMAP:
+               return "bitmap";
+       case JNODE_IO_HEAD:
+               return "io head";
+       case JNODE_INODE:
+               return "inode";
+       case LAST_JNODE_TYPE:
+               return "last";
+       default:{
+                       static char unknown[30];
+
+                       sprintf(unknown, "unknown %i", type);
+                       return unknown;
+               }
+       }
+}
+
+#define jnode_state_name( node, flag )                 \
+       ( JF_ISSET( ( node ), ( flag ) ) ? ((#flag "|")+6) : "" )
+
+/* debugging aid: output human readable information about @node */
+static void info_jnode(const char *prefix /* prefix to print */ ,
+                      const jnode * node /* node to print */ )
+{
+       assert("umka-068", prefix != NULL);
+
+       if (node == NULL) {
+               printk("%s: null\n", prefix);
+               return;
+       }
+
+       printk
+           ("%s: %p: state: %lx: [%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s%s], level: %i,"
+            " block: %s, d_count: %d, x_count: %d, "
+            "pg: %p, atom: %p, lock: %i:%i, type: %s, ", prefix, node,
+            node->state,
+            jnode_state_name(node, JNODE_PARSED),
+            jnode_state_name(node, JNODE_HEARD_BANSHEE),
+            jnode_state_name(node, JNODE_LEFT_CONNECTED),
+            jnode_state_name(node, JNODE_RIGHT_CONNECTED),
+            jnode_state_name(node, JNODE_ORPHAN),
+            jnode_state_name(node, JNODE_CREATED),
+            jnode_state_name(node, JNODE_RELOC),
+            jnode_state_name(node, JNODE_OVRWR),
+            jnode_state_name(node, JNODE_DIRTY),
+            jnode_state_name(node, JNODE_IS_DYING),
+            jnode_state_name(node, JNODE_RIP),
+            jnode_state_name(node, JNODE_MISSED_IN_CAPTURE),
+            jnode_state_name(node, JNODE_WRITEBACK),
+            jnode_state_name(node, JNODE_NEW),
+            jnode_state_name(node, JNODE_DKSET),
+            jnode_state_name(node, JNODE_REPACK),
+            jnode_state_name(node, JNODE_CLUSTER_PAGE),
+            jnode_get_level(node), sprint_address(jnode_get_block(node)),
+            atomic_read(&node->d_count), atomic_read(&node->x_count),
+            jnode_page(node), node->atom, 0, 0,
+            jnode_type_name(jnode_get_type(node)));
+       if (jnode_is_unformatted(node)) {
+               printk("inode: %llu, index: %lu, ",
+                      node->key.j.objectid, node->key.j.index);
+       }
+}
+
+/* debugging aid: check znode invariant and panic if it doesn't hold */
+static int jnode_invariant(const jnode * node, int tlocked, int jlocked)
+{
+       char const *failed_msg;
+       int result;
+       reiser4_tree *tree;
+
+       tree = jnode_get_tree(node);
+
+       assert("umka-063312", node != NULL);
+       assert("umka-064321", tree != NULL);
+
+       if (!jlocked && !tlocked)
+               spin_lock_jnode((jnode *) node);
+       if (!tlocked)
+               read_lock_tree(jnode_get_tree(node));
+       result = jnode_invariant_f(node, &failed_msg);
+       if (!result) {
+               info_jnode("corrupted node", node);
+               warning("jmacd-555", "Condition %s failed", failed_msg);
+       }
+       if (!tlocked)
+               read_unlock_tree(jnode_get_tree(node));
+       if (!jlocked && !tlocked)
+               spin_unlock_jnode((jnode *) node);
+       return result;
+}
+
+#endif                         /* REISER4_DEBUG */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/jnode.h linux-2.6.20/fs/reiser4/jnode.h
--- linux-2.6.20.orig/fs/reiser4/jnode.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/jnode.h     2007-05-06 14:50:43.734986973 +0400
@@ -0,0 +1,705 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Declaration of jnode. See jnode.c for details. */
+
+#ifndef __JNODE_H__
+#define __JNODE_H__
+
+#include "forward.h"
+#include "type_safe_hash.h"
+#include "txnmgr.h"
+#include "key.h"
+#include "debug.h"
+#include "dformat.h"
+#include "page_cache.h"
+#include "context.h"
+
+#include "plugin/plugin.h"
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <asm/bitops.h>
+#include <linux/list.h>
+#include <linux/rcupdate.h>
+
+/* declare hash table of jnodes (jnodes proper, that is, unformatted
+   nodes)  */
+TYPE_SAFE_HASH_DECLARE(j, jnode);
+
+/* declare hash table of znodes */
+TYPE_SAFE_HASH_DECLARE(z, znode);
+
+typedef struct {
+       __u64 objectid;
+       unsigned long index;
+       struct address_space *mapping;
+} jnode_key_t;
+
+/*
+   Jnode is the "base class" of other nodes in reiser4. It is also happens to
+   be exactly the node we use for unformatted tree nodes.
+
+   Jnode provides following basic functionality:
+
+   . reference counting and indexing.
+
+   . integration with page cache. Jnode has ->pg reference to which page can
+   be attached.
+
+   . interface to transaction manager. It is jnode that is kept in transaction
+   manager lists, attached to atoms, etc. (NOTE-NIKITA one may argue that this
+   means, there should be special type of jnode for inode.)
+
+   Locking:
+
+   Spin lock: the following fields are protected by the per-jnode spin lock:
+
+    ->state
+    ->atom
+    ->capture_link
+
+   Following fields are protected by the global tree lock:
+
+    ->link
+    ->key.z (content of ->key.z is only changed in znode_rehash())
+    ->key.j
+
+   Atomic counters
+
+    ->x_count
+    ->d_count
+
+    ->pg, and ->data are protected by spin lock for unused jnode and are
+    immutable for used jnode (one for which fs/reiser4/vfs_ops.c:releasable()
+    is false).
+
+    ->tree is immutable after creation
+
+   Unclear
+
+    ->blocknr: should be under jnode spin-lock, but current interface is based
+    on passing of block address.
+
+   If you ever need to spin lock two nodes at once, do this in "natural"
+   memory order: lock znode with lower address first. (See lock_two_nodes().)
+
+   Invariants involving this data-type:
+
+      [jnode-dirty]
+      [jnode-refs]
+      [jnode-oid]
+      [jnode-queued]
+      [jnode-atom-valid]
+      [jnode-page-binding]
+*/
+
+struct jnode {
+#if REISER4_DEBUG
+#define JMAGIC 0x52654973      /* "ReIs" */
+       int magic;
+#endif
+       /* FIRST CACHE LINE (16 bytes): data used by jload */
+
+       /* jnode's state: bitwise flags from the reiser4_jnode_state enum. */
+       /*   0 */ unsigned long state;
+
+       /* lock, protecting jnode's fields. */
+       /*   4 */ spinlock_t load;
+
+       /* counter of references to jnode itself. Increased on jref().
+          Decreased on jput().
+        */
+       /*   8 */ atomic_t x_count;
+
+       /* counter of references to jnode's data. Pin data page(s) in
+          memory while this is greater than 0. Increased on jload().
+          Decreased on jrelse().
+        */
+       /*   12 */ atomic_t d_count;
+
+       /* SECOND CACHE LINE: data used by hash table lookups */
+
+       /*   16 */ union {
+               /* znodes are hashed by block number */
+               reiser4_block_nr z;
+               /* unformatted nodes are hashed by mapping plus offset */
+               jnode_key_t j;
+       } key;
+
+       /* THIRD CACHE LINE */
+
+       /*   32 */ union {
+               /* pointers to maintain hash-table */
+               z_hash_link z;
+               j_hash_link j;
+       } link;
+
+       /* pointer to jnode page.  */
+       /*   36 */ struct page *pg;
+       /* pointer to node itself. This is page_address(node->pg) when page is
+          attached to the jnode
+        */
+       /*   40 */ void *data;
+
+       /*   44 */ reiser4_tree *tree;
+
+       /* FOURTH CACHE LINE: atom related fields */
+
+       /*   48 */ spinlock_t guard;
+
+       /* atom the block is in, if any */
+       /*   52 */ txn_atom *atom;
+
+       /* capture list */
+       /*   56 */ struct list_head capture_link;
+
+       /* FIFTH CACHE LINE */
+
+       /*   64 */ struct rcu_head rcu;
+       /* crosses cache line */
+
+       /* SIXTH CACHE LINE */
+
+       /* the real blocknr (where io is going to/from) */
+       /*   80 */ reiser4_block_nr blocknr;
+       /* Parent item type, unformatted and CRC need it for offset => key conversion.  */
+       /* NOTE: this parent_item_id looks like jnode type. */
+       /*   88 */ reiser4_plugin_id parent_item_id;
+       /*   92 */
+#if REISER4_DEBUG
+       /* number of pages referenced by the jnode (meaningful while capturing of
+          page clusters) */
+       int page_count;
+       /* list of all jnodes for debugging purposes. */
+       struct list_head jnodes;
+       /* how many times this jnode was written in one transaction */
+       int written;
+       /* this indicates which atom's list the jnode is on */
+       atom_list list;
+#endif
+} __attribute__ ((aligned(16)));
+
+/*
+ * jnode types. Enumeration of existing jnode types.
+ */
+typedef enum {
+       JNODE_UNFORMATTED_BLOCK,        /* unformatted block */
+       JNODE_FORMATTED_BLOCK,  /* formatted block, znode */
+       JNODE_BITMAP,           /* bitmap */
+       JNODE_IO_HEAD,          /* jnode representing a block in the
+                                * wandering log */
+       JNODE_INODE,            /* jnode embedded into inode */
+       LAST_JNODE_TYPE
+} jnode_type;
+
+/* jnode states */
+typedef enum {
+       /* jnode's page is loaded and data checked */
+       JNODE_PARSED = 0,
+       /* node was deleted, not all locks on it were released. This
+          node is empty and is going to be removed from the tree
+          shortly. */
+       JNODE_HEARD_BANSHEE = 1,
+       /* left sibling pointer is valid */
+       JNODE_LEFT_CONNECTED = 2,
+       /* right sibling pointer is valid */
+       JNODE_RIGHT_CONNECTED = 3,
+
+       /* znode was just created and doesn't yet have a pointer from
+          its parent */
+       JNODE_ORPHAN = 4,
+
+       /* this node was created by its transaction and has not been assigned
+          a block address. */
+       JNODE_CREATED = 5,
+
+       /* this node is currently relocated */
+       JNODE_RELOC = 6,
+       /* this node is currently wandered */
+       JNODE_OVRWR = 7,
+
+       /* this znode has been modified */
+       JNODE_DIRTY = 8,
+
+       /* znode lock is being invalidated */
+       JNODE_IS_DYING = 9,
+
+       /* THIS PLACE IS INTENTIONALLY LEFT BLANK */
+
+       /* jnode is queued for flushing. */
+       JNODE_FLUSH_QUEUED = 12,
+
+       /* In the following bits jnode type is encoded. */
+       JNODE_TYPE_1 = 13,
+       JNODE_TYPE_2 = 14,
+       JNODE_TYPE_3 = 15,
+
+       /* jnode is being destroyed */
+       JNODE_RIP = 16,
+
+       /* znode was not captured during locking (it might so be because
+          ->level != LEAF_LEVEL and lock_mode == READ_LOCK) */
+       JNODE_MISSED_IN_CAPTURE = 17,
+
+       /* write is in progress */
+       JNODE_WRITEBACK = 18,
+
+       /* FIXME: now it is used by crypto-compress plugin only */
+       JNODE_NEW = 19,
+
+       /* delimiting keys are already set for this znode. */
+       JNODE_DKSET = 20,
+
+       /* when this bit is set page and jnode can not be disconnected */
+       JNODE_WRITE_PREPARED = 21,
+
+       JNODE_CLUSTER_PAGE = 22,
+       /* Jnode is marked for repacking, that means the reiser4 flush and the
+        * block allocator should process this node special way  */
+       JNODE_REPACK = 23,
+       /* node should be converted by flush in squalloc phase */
+       JNODE_CONVERTIBLE = 24,
+       /*
+        * When jnode is dirtied for the first time in given transaction,
+        * do_jnode_make_dirty() checks whether this jnode can possible became
+        * member of overwrite set. If so, this bit is set, and one block is
+        * reserved in the ->flush_reserved space of atom.
+        *
+        * This block is "used" (and JNODE_FLUSH_RESERVED bit is cleared) when
+        *
+        *     (1) flush decides that we want this block to go into relocate
+        *     set after all.
+        *
+        *     (2) wandering log is allocated (by log writer)
+        *
+        *     (3) extent is allocated
+        *
+        */
+       JNODE_FLUSH_RESERVED = 29
+} reiser4_jnode_state;
+
+/* Macros for accessing the jnode state. */
+
+static inline void JF_CLR(jnode * j, int f)
+{
+       assert("unknown-1", j->magic == JMAGIC);
+       clear_bit(f, &j->state);
+}
+static inline int JF_ISSET(const jnode * j, int f)
+{
+       assert("unknown-2", j->magic == JMAGIC);
+       return test_bit(f, &((jnode *) j)->state);
+}
+static inline void JF_SET(jnode * j, int f)
+{
+       assert("unknown-3", j->magic == JMAGIC);
+       set_bit(f, &j->state);
+}
+
+static inline int JF_TEST_AND_SET(jnode * j, int f)
+{
+       assert("unknown-4", j->magic == JMAGIC);
+       return test_and_set_bit(f, &j->state);
+}
+
+static inline void spin_lock_jnode(jnode *node)
+{
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(rw_locked_tree) &&
+                   LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(spin_locked_zlock) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_LT(spin_locked_jnode, 2)));
+
+       spin_lock(&(node->guard));
+
+       LOCK_CNT_INC(spin_locked_jnode);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void spin_unlock_jnode(jnode *node)
+{
+       assert_spin_locked(&(node->guard));
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_jnode));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(spin_locked_jnode);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&(node->guard));
+}
+
+static inline int jnode_is_in_deleteset(const jnode * node)
+{
+       return JF_ISSET(node, JNODE_RELOC);
+}
+
+extern int init_jnodes(void);
+extern void done_jnodes(void);
+
+/* Jnode routines */
+extern jnode *jalloc(void);
+extern void jfree(jnode * node) NONNULL;
+extern jnode *jclone(jnode *);
+extern jnode *jlookup(reiser4_tree * tree,
+                     oid_t objectid, unsigned long ind) NONNULL;
+extern jnode *jfind(struct address_space *, unsigned long index) NONNULL;
+extern jnode *jnode_by_page(struct page *pg) NONNULL;
+extern jnode *jnode_of_page(struct page *pg) NONNULL;
+void jnode_attach_page(jnode * node, struct page *pg);
+
+void unhash_unformatted_jnode(jnode *);
+extern jnode *page_next_jnode(jnode * node) NONNULL;
+extern void jnode_init(jnode * node, reiser4_tree * tree, jnode_type) NONNULL;
+extern void jnode_make_dirty(jnode * node) NONNULL;
+extern void jnode_make_clean(jnode * node) NONNULL;
+extern void jnode_make_wander_nolock(jnode * node) NONNULL;
+extern void jnode_make_wander(jnode *) NONNULL;
+extern void znode_make_reloc(znode *, flush_queue_t *) NONNULL;
+extern void unformatted_make_reloc(jnode *, flush_queue_t *) NONNULL;
+extern struct address_space *jnode_get_mapping(const jnode * node) NONNULL;
+
+/**
+ * jnode_get_block
+ * @node: jnode to query
+ *
+ */
+static inline const reiser4_block_nr *jnode_get_block(const jnode *node)
+{
+       assert("nikita-528", node != NULL);
+
+       return &node->blocknr;
+}
+
+/**
+ * jnode_set_block
+ * @node: jnode to update
+ * @blocknr: new block nr
+ */
+static inline void jnode_set_block(jnode *node, const reiser4_block_nr *blocknr)
+{
+       assert("nikita-2020", node != NULL);
+       assert("umka-055", blocknr != NULL);
+       node->blocknr = *blocknr;
+}
+
+
+/* block number for IO. Usually this is the same as jnode_get_block(), unless
+ * jnode was emergency flushed---then block number chosen by eflush is
+ * used. */
+static inline const reiser4_block_nr *jnode_get_io_block(jnode * node)
+{
+       assert("nikita-2768", node != NULL);
+       assert_spin_locked(&(node->guard));
+
+       return jnode_get_block(node);
+}
+
+/* Jnode flush interface. */
+extern reiser4_blocknr_hint *reiser4_pos_hint(flush_pos_t * pos);
+extern flush_queue_t *reiser4_pos_fq(flush_pos_t * pos);
+
+/* FIXME-VS: these are used in plugin/item/extent.c */
+
+/* does extent_get_block have to be called */
+#define jnode_mapped(node)     JF_ISSET (node, JNODE_MAPPED)
+#define jnode_set_mapped(node) JF_SET (node, JNODE_MAPPED)
+
+/* the node should be converted during flush squalloc phase */
+#define jnode_convertible(node)        JF_ISSET (node, JNODE_CONVERTIBLE)
+#define jnode_set_convertible(node)    JF_SET (node, JNODE_CONVERTIBLE)
+
+/* Macros to convert from jnode to znode, znode to jnode.  These are macros
+   because C doesn't allow overloading of const prototypes. */
+#define ZJNODE(x) (& (x) -> zjnode)
+#define JZNODE(x)                                              \
+({                                                             \
+       typeof (x) __tmp_x;                                     \
+                                                               \
+       __tmp_x = (x);                                          \
+       assert ("jmacd-1300", jnode_is_znode (__tmp_x));        \
+       (znode*) __tmp_x;                                       \
+})
+
+extern int jnodes_tree_init(reiser4_tree * tree);
+extern int jnodes_tree_done(reiser4_tree * tree);
+
+#if REISER4_DEBUG
+
+extern int znode_is_any_locked(const znode * node);
+extern void jnode_list_remove(jnode * node);
+
+#else
+
+#define jnode_list_remove(node) noop
+
+#endif
+
+int znode_is_root(const znode * node) NONNULL;
+
+/* bump reference counter on @node */
+static inline void add_x_ref(jnode * node /* node to increase x_count of */ )
+{
+       assert("nikita-1911", node != NULL);
+
+       atomic_inc(&node->x_count);
+       LOCK_CNT_INC(x_refs);
+}
+
+static inline void dec_x_ref(jnode * node)
+{
+       assert("nikita-3215", node != NULL);
+       assert("nikita-3216", atomic_read(&node->x_count) > 0);
+
+       atomic_dec(&node->x_count);
+       assert("nikita-3217", LOCK_CNT_GTZ(x_refs));
+       LOCK_CNT_DEC(x_refs);
+}
+
+/* jref() - increase counter of references to jnode/znode (x_count) */
+static inline jnode *jref(jnode * node)
+{
+       assert("jmacd-508", (node != NULL) && !IS_ERR(node));
+       add_x_ref(node);
+       return node;
+}
+
+/* get the page of jnode */
+static inline struct page *jnode_page(const jnode * node)
+{
+       return node->pg;
+}
+
+/* return pointer to jnode data */
+static inline char *jdata(const jnode * node)
+{
+       assert("nikita-1415", node != NULL);
+       assert("nikita-3198", jnode_page(node) != NULL);
+       return node->data;
+}
+
+static inline int jnode_is_loaded(const jnode * node)
+{
+       assert("zam-506", node != NULL);
+       return atomic_read(&node->d_count) > 0;
+}
+
+extern void page_clear_jnode(struct page *page, jnode * node) NONNULL;
+
+static inline void jnode_set_reloc(jnode * node)
+{
+       assert("nikita-2431", node != NULL);
+       assert("nikita-2432", !JF_ISSET(node, JNODE_OVRWR));
+       JF_SET(node, JNODE_RELOC);
+}
+
+/* jload/jwrite/junload give a bread/bwrite/brelse functionality for jnodes */
+
+extern int jload_gfp(jnode *, gfp_t, int do_kmap) NONNULL;
+
+static inline int jload(jnode *node)
+{
+       return jload_gfp(node, reiser4_ctx_gfp_mask_get(), 1);
+}
+
+extern int jinit_new(jnode *, gfp_t) NONNULL;
+extern int jstartio(jnode *) NONNULL;
+
+extern void jdrop(jnode *) NONNULL;
+extern int jwait_io(jnode *, int rw) NONNULL;
+
+void jload_prefetch(jnode *);
+
+extern jnode *reiser4_alloc_io_head(const reiser4_block_nr * block) NONNULL;
+extern void reiser4_drop_io_head(jnode * node) NONNULL;
+
+static inline reiser4_tree *jnode_get_tree(const jnode * node)
+{
+       assert("nikita-2691", node != NULL);
+       return node->tree;
+}
+
+extern void pin_jnode_data(jnode *);
+extern void unpin_jnode_data(jnode *);
+
+static inline jnode_type jnode_get_type(const jnode * node)
+{
+       static const unsigned long state_mask =
+           (1 << JNODE_TYPE_1) | (1 << JNODE_TYPE_2) | (1 << JNODE_TYPE_3);
+
+       static jnode_type mask_to_type[] = {
+               /*  JNODE_TYPE_3 : JNODE_TYPE_2 : JNODE_TYPE_1 */
+
+               /* 000 */
+               [0] = JNODE_FORMATTED_BLOCK,
+               /* 001 */
+               [1] = JNODE_UNFORMATTED_BLOCK,
+               /* 010 */
+               [2] = JNODE_BITMAP,
+               /* 011 */
+               [3] = LAST_JNODE_TYPE,  /*invalid */
+               /* 100 */
+               [4] = JNODE_INODE,
+               /* 101 */
+               [5] = LAST_JNODE_TYPE,
+               /* 110 */
+               [6] = JNODE_IO_HEAD,
+               /* 111 */
+               [7] = LAST_JNODE_TYPE,  /* invalid */
+       };
+
+       return mask_to_type[(node->state & state_mask) >> JNODE_TYPE_1];
+}
+
+/* returns true if node is a znode */
+static inline int jnode_is_znode(const jnode * node)
+{
+       return jnode_get_type(node) == JNODE_FORMATTED_BLOCK;
+}
+
+static inline int jnode_is_flushprepped(jnode * node)
+{
+       assert("jmacd-78212", node != NULL);
+       assert_spin_locked(&(node->guard));
+       return !JF_ISSET(node, JNODE_DIRTY) || JF_ISSET(node, JNODE_RELOC) ||
+               JF_ISSET(node, JNODE_OVRWR);
+}
+
+/* Return true if @node has already been processed by the squeeze and allocate
+   process.  This implies the block address has been finalized for the
+   duration of this atom (or it is clean and will remain in place).  If this
+   returns true you may use the block number as a hint. */
+static inline int jnode_check_flushprepped(jnode * node)
+{
+       int result;
+
+       /* It must be clean or relocated or wandered.  New allocations are set to relocate. */
+       spin_lock_jnode(node);
+       result = jnode_is_flushprepped(node);
+       spin_unlock_jnode(node);
+       return result;
+}
+
+/* returns true if node is unformatted */
+static inline int jnode_is_unformatted(const jnode * node)
+{
+       assert("jmacd-0123", node != NULL);
+       return jnode_get_type(node) == JNODE_UNFORMATTED_BLOCK;
+}
+
+/* returns true if node represents a cluster cache page */
+static inline int jnode_is_cluster_page(const jnode * node)
+{
+       assert("edward-50", node != NULL);
+       return (JF_ISSET(node, JNODE_CLUSTER_PAGE));
+}
+
+/* returns true is node is builtin inode's jnode */
+static inline int jnode_is_inode(const jnode * node)
+{
+       assert("vs-1240", node != NULL);
+       return jnode_get_type(node) == JNODE_INODE;
+}
+
+static inline jnode_plugin *jnode_ops_of(const jnode_type type)
+{
+       assert("nikita-2367", type < LAST_JNODE_TYPE);
+       return jnode_plugin_by_id((reiser4_plugin_id) type);
+}
+
+static inline jnode_plugin *jnode_ops(const jnode * node)
+{
+       assert("nikita-2366", node != NULL);
+
+       return jnode_ops_of(jnode_get_type(node));
+}
+
+/* Get the index of a block. */
+static inline unsigned long jnode_get_index(jnode * node)
+{
+       return jnode_ops(node)->index(node);
+}
+
+/* return true if "node" is the root */
+static inline int jnode_is_root(const jnode * node)
+{
+       return jnode_is_znode(node) && znode_is_root(JZNODE(node));
+}
+
+extern struct address_space *mapping_jnode(const jnode * node);
+extern unsigned long index_jnode(const jnode * node);
+
+static inline void jput(jnode * node);
+extern void jput_final(jnode * node);
+
+/* bump data counter on @node */
+static inline void add_d_ref(jnode * node /* node to increase d_count of */ )
+{
+       assert("nikita-1962", node != NULL);
+
+       atomic_inc(&node->d_count);
+       if (jnode_is_unformatted(node) || jnode_is_znode(node))
+               LOCK_CNT_INC(d_refs);
+}
+
+/* jput() - decrement x_count reference counter on znode.
+
+   Count may drop to 0, jnode stays in cache until memory pressure causes the
+   eviction of its page. The c_count variable also ensures that children are
+   pressured out of memory before the parent. The jnode remains hashed as
+   long as the VM allows its page to stay in memory.
+*/
+static inline void jput(jnode * node)
+{
+       assert("jmacd-509", node != NULL);
+       assert("jmacd-510", atomic_read(&node->x_count) > 0);
+       assert("zam-926", reiser4_schedulable());
+       LOCK_CNT_DEC(x_refs);
+
+       rcu_read_lock();
+       /*
+        * we don't need any kind of lock here--jput_final() uses RCU.
+        */
+       if (unlikely(atomic_dec_and_test(&node->x_count))) {
+               jput_final(node);
+       } else
+               rcu_read_unlock();
+       assert("nikita-3473", reiser4_schedulable());
+}
+
+extern void jrelse(jnode * node);
+extern void jrelse_tail(jnode * node);
+
+extern jnode *jnode_rip_sync(reiser4_tree * t, jnode * node);
+
+/* resolve race with jput */
+static inline jnode *jnode_rip_check(reiser4_tree * tree, jnode * node)
+{
+       if (unlikely(JF_ISSET(node, JNODE_RIP)))
+               node = jnode_rip_sync(tree, node);
+       return node;
+}
+
+extern reiser4_key *jnode_build_key(const jnode *node, reiser4_key * key);
+
+#if REISER4_DEBUG
+extern int jnode_invariant_f(const jnode *node, char const **msg);
+#endif
+
+extern jnode_plugin jnode_plugins[LAST_JNODE_TYPE];
+
+/* __JNODE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/kassign.c linux-2.6.20/fs/reiser4/kassign.c
--- linux-2.6.20.orig/fs/reiser4/kassign.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/kassign.c   2007-05-06 14:50:43.734986973 +0400
@@ -0,0 +1,661 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Key assignment policy implementation */
+
+/*
+ * In reiser4 every piece of file system data and meta-data has a key. Keys
+ * are used to store information in and retrieve it from reiser4 internal
+ * tree. In addition to this, keys define _ordering_ of all file system
+ * information: things having close keys are placed into the same or
+ * neighboring (in the tree order) nodes of the tree. As our block allocator
+ * tries to respect tree order (see flush.c), keys also define order in which
+ * things are laid out on the disk, and hence, affect performance directly.
+ *
+ * Obviously, assignment of keys to data and meta-data should be consistent
+ * across whole file system. Algorithm that calculates a key for a given piece
+ * of data or meta-data is referred to as "key assignment".
+ *
+ * Key assignment is too expensive to be implemented as a plugin (that is,
+ * with an ability to support different key assignment schemas in the same
+ * compiled kernel image). As a compromise, all key-assignment functions and
+ * data-structures are collected in this single file, so that modifications to
+ * key assignment algorithm can be localized. Additional changes may be
+ * required in key.[ch].
+ *
+ * Current default reiser4 key assignment algorithm is dubbed "Plan A". As one
+ * may guess, there is "Plan B" too.
+ *
+ */
+
+/*
+ * Additional complication with key assignment implementation is a requirement
+ * to support different key length.
+ */
+
+/*
+ *                   KEY ASSIGNMENT: PLAN A, LONG KEYS.
+ *
+ * DIRECTORY ITEMS
+ *
+ *  |       60     | 4 | 7 |1|   56        |        64        |        64       |
+ *  +--------------+---+---+-+-------------+------------------+-----------------+
+ *  |    dirid     | 0 | F |H|  prefix-1   |    prefix-2      |  prefix-3/hash  |
+ *  +--------------+---+---+-+-------------+------------------+-----------------+
+ *  |                  |                   |                  |                 |
+ *  |    8 bytes       |      8 bytes      |     8 bytes      |     8 bytes     |
+ *
+ * dirid         objectid of directory this item is for
+ *
+ * F             fibration, see fs/reiser4/plugin/fibration.[ch]
+ *
+ * H             1 if last 8 bytes of the key contain hash,
+ *               0 if last 8 bytes of the key contain prefix-3
+ *
+ * prefix-1      first 7 characters of file name.
+ *               Padded by zeroes if name is not long enough.
+ *
+ * prefix-2      next 8 characters of the file name.
+ *
+ * prefix-3      next 8 characters of the file name.
+ *
+ * hash          hash of the rest of file name (i.e., portion of file
+ *               name not included into prefix-1 and prefix-2).
+ *
+ * File names shorter than 23 (== 7 + 8 + 8) characters are completely encoded
+ * in the key. Such file names are called "short". They are distinguished by H
+ * bit set 0 in the key.
+ *
+ * Other file names are "long". For long name, H bit is 1, and first 15 (== 7
+ * + 8) characters are encoded in prefix-1 and prefix-2 portions of the
+ * key. Last 8 bytes of the key are occupied by hash of the remaining
+ * characters of the name.
+ *
+ * This key assignment reaches following important goals:
+ *
+ *     (1) directory entries are sorted in approximately lexicographical
+ *     order.
+ *
+ *     (2) collisions (when multiple directory items have the same key), while
+ *     principally unavoidable in a tree with fixed length keys, are rare.
+ *
+ * STAT DATA
+ *
+ *  |       60     | 4 |       64        | 4 |     60       |        64       |
+ *  +--------------+---+-----------------+---+--------------+-----------------+
+ *  |  locality id | 1 |    ordering     | 0 |  objectid    |        0        |
+ *  +--------------+---+-----------------+---+--------------+-----------------+
+ *  |                  |                 |                  |                 |
+ *  |    8 bytes       |    8 bytes      |     8 bytes      |     8 bytes     |
+ *
+ * locality id     object id of a directory where first name was created for
+ *                 the object
+ *
+ * ordering        copy of second 8-byte portion of the key of directory
+ *                 entry for the first name of this object. Ordering has a form
+ *                         {
+ *                                 fibration :7;
+ *                                 h         :1;
+ *                                 prefix1   :56;
+ *                         }
+ *                 see description of key for directory entry above.
+ *
+ * objectid        object id for this object
+ *
+ * This key assignment policy is designed to keep stat-data in the same order
+ * as corresponding directory items, thus speeding up readdir/stat types of
+ * workload.
+ *
+ * FILE BODY
+ *
+ *  |       60     | 4 |       64        | 4 |     60       |        64       |
+ *  +--------------+---+-----------------+---+--------------+-----------------+
+ *  |  locality id | 4 |    ordering     | 0 |  objectid    |      offset     |
+ *  +--------------+---+-----------------+---+--------------+-----------------+
+ *  |                  |                 |                  |                 |
+ *  |    8 bytes       |    8 bytes      |     8 bytes      |     8 bytes     |
+ *
+ * locality id     object id of a directory where first name was created for
+ *                 the object
+ *
+ * ordering        the same as in the key of stat-data for this object
+ *
+ * objectid        object id for this object
+ *
+ * offset          logical offset from the beginning of this file.
+ *                 Measured in bytes.
+ *
+ *
+ *                   KEY ASSIGNMENT: PLAN A, SHORT KEYS.
+ *
+ * DIRECTORY ITEMS
+ *
+ *  |       60     | 4 | 7 |1|   56        |        64       |
+ *  +--------------+---+---+-+-------------+-----------------+
+ *  |    dirid     | 0 | F |H|  prefix-1   |  prefix-2/hash  |
+ *  +--------------+---+---+-+-------------+-----------------+
+ *  |                  |                   |                 |
+ *  |    8 bytes       |      8 bytes      |     8 bytes     |
+ *
+ * dirid         objectid of directory this item is for
+ *
+ * F             fibration, see fs/reiser4/plugin/fibration.[ch]
+ *
+ * H             1 if last 8 bytes of the key contain hash,
+ *               0 if last 8 bytes of the key contain prefix-2
+ *
+ * prefix-1      first 7 characters of file name.
+ *               Padded by zeroes if name is not long enough.
+ *
+ * prefix-2      next 8 characters of the file name.
+ *
+ * hash          hash of the rest of file name (i.e., portion of file
+ *               name not included into prefix-1).
+ *
+ * File names shorter than 15 (== 7 + 8) characters are completely encoded in
+ * the key. Such file names are called "short". They are distinguished by H
+ * bit set in the key.
+ *
+ * Other file names are "long". For long name, H bit is 0, and first 7
+ * characters are encoded in prefix-1 portion of the key. Last 8 bytes of the
+ * key are occupied by hash of the remaining characters of the name.
+ *
+ * STAT DATA
+ *
+ *  |       60     | 4 | 4 |     60       |        64       |
+ *  +--------------+---+---+--------------+-----------------+
+ *  |  locality id | 1 | 0 |  objectid    |        0        |
+ *  +--------------+---+---+--------------+-----------------+
+ *  |                  |                  |                 |
+ *  |    8 bytes       |     8 bytes      |     8 bytes     |
+ *
+ * locality id     object id of a directory where first name was created for
+ *                 the object
+ *
+ * objectid        object id for this object
+ *
+ * FILE BODY
+ *
+ *  |       60     | 4 | 4 |     60       |        64       |
+ *  +--------------+---+---+--------------+-----------------+
+ *  |  locality id | 4 | 0 |  objectid    |      offset     |
+ *  +--------------+---+---+--------------+-----------------+
+ *  |                  |                  |                 |
+ *  |    8 bytes       |     8 bytes      |     8 bytes     |
+ *
+ * locality id     object id of a directory where first name was created for
+ *                 the object
+ *
+ * objectid        object id for this object
+ *
+ * offset          logical offset from the beginning of this file.
+ *                 Measured in bytes.
+ *
+ *
+ */
+
+#include "debug.h"
+#include "key.h"
+#include "kassign.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "super.h"
+#include "dscale.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block, etc  */
+
+/* bitmask for H bit (see comment at the beginning of this file */
+static const __u64 longname_mark = 0x0100000000000000ull;
+/* bitmask for F and H portions of the key. */
+static const __u64 fibration_mask = 0xff00000000000000ull;
+
+/* return true if name is not completely encoded in @key */
+int is_longname_key(const reiser4_key * key)
+{
+       __u64 highpart;
+
+       assert("nikita-2863", key != NULL);
+       if (get_key_type(key) != KEY_FILE_NAME_MINOR)
+               reiser4_print_key("oops", key);
+       assert("nikita-2864", get_key_type(key) == KEY_FILE_NAME_MINOR);
+
+       if (REISER4_LARGE_KEY)
+               highpart = get_key_ordering(key);
+       else
+               highpart = get_key_objectid(key);
+
+       return (highpart & longname_mark) ? 1 : 0;
+}
+
+/* return true if @name is too long to be completely encoded in the key */
+int is_longname(const char *name UNUSED_ARG, int len)
+{
+       if (REISER4_LARGE_KEY)
+               return len > 23;
+       else
+               return len > 15;
+}
+
+/* code ascii string into __u64.
+
+   Put characters of @name into result (@str) one after another starting
+   from @start_idx-th highest (arithmetically) byte. This produces
+   endian-safe encoding. memcpy(2) will not do.
+
+*/
+static __u64 pack_string(const char *name /* string to encode */ ,
+                        int start_idx  /* highest byte in result from
+                                        * which to start encoding */ )
+{
+       unsigned i;
+       __u64 str;
+
+       str = 0;
+       for (i = 0; (i < sizeof str - start_idx) && name[i]; ++i) {
+               str <<= 8;
+               str |= (unsigned char)name[i];
+       }
+       str <<= (sizeof str - i - start_idx) << 3;
+       return str;
+}
+
+/* opposite to pack_string(). Takes value produced by pack_string(), restores
+ * string encoded in it and stores result in @buf */
+char * reiser4_unpack_string(__u64 value, char *buf)
+{
+       do {
+               *buf = value >> (64 - 8);
+               if (*buf)
+                       ++buf;
+               value <<= 8;
+       } while (value != 0);
+       *buf = 0;
+       return buf;
+}
+
+/* obtain name encoded in @key and store it in @buf */
+char *extract_name_from_key(const reiser4_key * key, char *buf)
+{
+       char *c;
+
+       assert("nikita-2868", !is_longname_key(key));
+
+       c = buf;
+       if (REISER4_LARGE_KEY) {
+               c = reiser4_unpack_string(get_key_ordering(key) &
+                                         ~fibration_mask, c);
+               c = reiser4_unpack_string(get_key_fulloid(key), c);
+       } else
+               c = reiser4_unpack_string(get_key_fulloid(key) &
+                                         ~fibration_mask, c);
+       reiser4_unpack_string(get_key_offset(key), c);
+       return buf;
+}
+
+/**
+ * complete_entry_key - calculate entry key by name
+ * @dir: directory where entry is (or will be) in
+ * @name: name to calculate key of
+ * @len: lenth of name
+ * @result: place to store result in
+ *
+ * Sets fields of entry key @result which depend on file name.
+ * When REISER4_LARGE_KEY is defined three fields of @result are set: ordering,
+ * objectid and offset. Otherwise, objectid and offset are set.
+ */
+void complete_entry_key(const struct inode *dir, const char *name,
+                       int len, reiser4_key *result)
+{
+#if REISER4_LARGE_KEY
+       __u64 ordering;
+       __u64 objectid;
+       __u64 offset;
+
+       assert("nikita-1139", dir != NULL);
+       assert("nikita-1142", result != NULL);
+       assert("nikita-2867", strlen(name) == len);
+
+       /*
+        * key allocation algorithm for directory entries in case of large
+        * keys:
+        *
+        * If name is not longer than 7 + 8 + 8 = 23 characters, put first 7
+        * characters into ordering field of key, next 8 charactes (if any)
+        * into objectid field of key and next 8 ones (of any) into offset
+        * field of key
+        *
+        * If file name is longer than 23 characters, put first 7 characters
+        * into key's ordering, next 8 to objectid and hash of remaining
+        * characters into offset field.
+        *
+        * To distinguish above cases, in latter set up unused high bit in
+        * ordering field.
+        */
+
+       /* [0-6] characters to ordering */
+       ordering = pack_string(name, 1);
+       if (len > 7) {
+               /* [7-14] characters to objectid */
+               objectid = pack_string(name + 7, 0);
+               if (len > 15) {
+                       if (len <= 23) {
+                               /* [15-23] characters to offset */
+                               offset = pack_string(name + 15, 0);
+                       } else {
+                               /* note in a key the fact that offset contains hash. */
+                               ordering |= longname_mark;
+
+                               /* offset is the hash of the file name's tail. */
+                               offset = inode_hash_plugin(dir)->hash(name + 15,
+                                                                     len - 15);
+                       }
+               } else {
+                       offset = 0ull;
+               }
+       } else {
+               objectid = 0ull;
+               offset = 0ull;
+       }
+
+       assert("nikita-3480", inode_fibration_plugin(dir) != NULL);
+       ordering |= inode_fibration_plugin(dir)->fibre(dir, name, len);
+
+       set_key_ordering(result, ordering);
+       set_key_fulloid(result, objectid);
+       set_key_offset(result, offset);
+       return;
+
+#else
+       __u64 objectid;
+       __u64 offset;
+
+       assert("nikita-1139", dir != NULL);
+       assert("nikita-1142", result != NULL);
+       assert("nikita-2867", strlen(name) == len);
+
+       /*
+        * key allocation algorithm for directory entries in case of not large
+        * keys:
+        *
+        * If name is not longer than 7 + 8 = 15 characters, put first 7
+        * characters into objectid field of key, next 8 charactes (if any)
+        * into offset field of key
+        *
+        * If file name is longer than 15 characters, put first 7 characters
+        * into key's objectid, and hash of remaining characters into offset
+        * field.
+        *
+        * To distinguish above cases, in latter set up unused high bit in
+        * objectid field.
+        */
+
+       /* [0-6] characters to objectid */
+       objectid = pack_string(name, 1);
+       if (len > 7) {
+               if (len <= 15) {
+                       /* [7-14] characters to offset */
+                       offset = pack_string(name + 7, 0);
+               } else {
+                       /* note in a key the fact that offset contains hash. */
+                       objectid |= longname_mark;
+
+                       /* offset is the hash of the file name. */
+                       offset = inode_hash_plugin(dir)->hash(name + 7,
+                                                             len - 7);
+               }
+       } else
+               offset = 0ull;
+
+       assert("nikita-3480", inode_fibration_plugin(dir) != NULL);
+       objectid |= inode_fibration_plugin(dir)->fibre(dir, name, len);
+
+       set_key_fulloid(result, objectid);
+       set_key_offset(result, offset);
+       return;
+#endif                         /* ! REISER4_LARGE_KEY */
+}
+
+/* true, if @key is the key of "." */
+int is_dot_key(const reiser4_key * key /* key to check */ )
+{
+       assert("nikita-1717", key != NULL);
+       assert("nikita-1718", get_key_type(key) == KEY_FILE_NAME_MINOR);
+       return
+           (get_key_ordering(key) == 0ull) &&
+           (get_key_objectid(key) == 0ull) && (get_key_offset(key) == 0ull);
+}
+
+/* build key for stat-data.
+
+   return key of stat-data of this object. This should became sd plugin
+   method in the future. For now, let it be here.
+
+*/
+reiser4_key *build_sd_key(const struct inode * target /* inode of an object */ ,
+                         reiser4_key * result  /* resulting key of @target
+                                                  stat-data */ )
+{
+       assert("nikita-261", result != NULL);
+
+       reiser4_key_init(result);
+       set_key_locality(result, reiser4_inode_data(target)->locality_id);
+       set_key_ordering(result, get_inode_ordering(target));
+       set_key_objectid(result, get_inode_oid(target));
+       set_key_type(result, KEY_SD_MINOR);
+       set_key_offset(result, (__u64) 0);
+       return result;
+}
+
+/* encode part of key into &obj_key_id
+
+   This encodes into @id part of @key sufficient to restore @key later,
+   given that latter is key of object (key of stat-data).
+
+   See &obj_key_id
+*/
+int build_obj_key_id(const reiser4_key * key /* key to encode */ ,
+                    obj_key_id * id /* id where key is encoded in */ )
+{
+       assert("nikita-1151", key != NULL);
+       assert("nikita-1152", id != NULL);
+
+       memcpy(id, key, sizeof *id);
+       return 0;
+}
+
+/* encode reference to @obj in @id.
+
+   This is like build_obj_key_id() above, but takes inode as parameter. */
+int build_inode_key_id(const struct inode *obj /* object to build key of */ ,
+                      obj_key_id * id /* result */ )
+{
+       reiser4_key sdkey;
+
+       assert("nikita-1166", obj != NULL);
+       assert("nikita-1167", id != NULL);
+
+       build_sd_key(obj, &sdkey);
+       build_obj_key_id(&sdkey, id);
+       return 0;
+}
+
+/* decode @id back into @key
+
+   Restore key of object stat-data from @id. This is dual to
+   build_obj_key_id() above.
+*/
+int extract_key_from_id(const obj_key_id * id  /* object key id to extract key
+                                                * from */ ,
+                       reiser4_key * key /* result */ )
+{
+       assert("nikita-1153", id != NULL);
+       assert("nikita-1154", key != NULL);
+
+       reiser4_key_init(key);
+       memcpy(key, id, sizeof *id);
+       return 0;
+}
+
+/* extract objectid of directory from key of directory entry within said
+   directory.
+   */
+oid_t extract_dir_id_from_key(const reiser4_key * de_key       /* key of
+                                                                * directory
+                                                                * entry */ )
+{
+       assert("nikita-1314", de_key != NULL);
+       return get_key_locality(de_key);
+}
+
+/* encode into @id key of directory entry.
+
+   Encode into @id information sufficient to later distinguish directory
+   entries within the same directory. This is not whole key, because all
+   directory entries within directory item share locality which is equal
+   to objectid of their directory.
+
+*/
+int build_de_id(const struct inode *dir /* inode of directory */ ,
+               const struct qstr *name /* name to be given to @obj by
+                                        * directory entry being
+                                        * constructed */ ,
+               de_id * id /* short key of directory entry */ )
+{
+       reiser4_key key;
+
+       assert("nikita-1290", dir != NULL);
+       assert("nikita-1292", id != NULL);
+
+       /* NOTE-NIKITA this is suboptimal. */
+       inode_dir_plugin(dir)->build_entry_key(dir, name, &key);
+       return build_de_id_by_key(&key, id);
+}
+
+/* encode into @id key of directory entry.
+
+   Encode into @id information sufficient to later distinguish directory
+   entries within the same directory. This is not whole key, because all
+   directory entries within directory item share locality which is equal
+   to objectid of their directory.
+
+*/
+int build_de_id_by_key(const reiser4_key * entry_key   /* full key of directory
+                                                        * entry */ ,
+                      de_id * id /* short key of directory entry */ )
+{
+       memcpy(id, ((__u64 *) entry_key) + 1, sizeof *id);
+       return 0;
+}
+
+/* restore from @id key of directory entry.
+
+   Function dual to build_de_id(): given @id and locality, build full
+   key of directory entry within directory item.
+
+*/
+int extract_key_from_de_id(const oid_t locality        /* locality of directory
+                                                * entry */ ,
+                          const de_id * id /* directory entry id */ ,
+                          reiser4_key * key /* result */ )
+{
+       /* no need to initialise key here: all fields are overwritten */
+       memcpy(((__u64 *) key) + 1, id, sizeof *id);
+       set_key_locality(key, locality);
+       set_key_type(key, KEY_FILE_NAME_MINOR);
+       return 0;
+}
+
+/* compare two &de_id's */
+cmp_t de_id_cmp(const de_id * id1 /* first &de_id to compare */ ,
+               const de_id * id2 /* second &de_id to compare */ )
+{
+       /* NOTE-NIKITA ugly implementation */
+       reiser4_key k1;
+       reiser4_key k2;
+
+       extract_key_from_de_id((oid_t) 0, id1, &k1);
+       extract_key_from_de_id((oid_t) 0, id2, &k2);
+       return keycmp(&k1, &k2);
+}
+
+/* compare &de_id with key */
+cmp_t de_id_key_cmp(const de_id * id /* directory entry id to compare */ ,
+                   const reiser4_key * key /* key to compare */ )
+{
+       cmp_t result;
+       reiser4_key *k1;
+
+       k1 = (reiser4_key *) (((unsigned long)id) - sizeof key->el[0]);
+       result = KEY_DIFF_EL(k1, key, 1);
+       if (result == EQUAL_TO) {
+               result = KEY_DIFF_EL(k1, key, 2);
+               if (REISER4_LARGE_KEY && result == EQUAL_TO) {
+                       result = KEY_DIFF_EL(k1, key, 3);
+               }
+       }
+       return result;
+}
+
+/*
+ * return number of bytes necessary to encode @inode identity.
+ */
+int inode_onwire_size(const struct inode *inode)
+{
+       int result;
+
+       result = dscale_bytes(get_inode_oid(inode));
+       result += dscale_bytes(get_inode_locality(inode));
+
+       /*
+        * ordering is large (it usually has highest bits set), so it makes
+        * little sense to dscale it.
+        */
+       if (REISER4_LARGE_KEY)
+               result += sizeof(get_inode_ordering(inode));
+       return result;
+}
+
+/*
+ * encode @inode identity at @start
+ */
+char *build_inode_onwire(const struct inode *inode, char *start)
+{
+       start += dscale_write(start, get_inode_locality(inode));
+       start += dscale_write(start, get_inode_oid(inode));
+
+       if (REISER4_LARGE_KEY) {
+               put_unaligned(cpu_to_le64(get_inode_ordering(inode)), (__le64 *)start);
+               start += sizeof(get_inode_ordering(inode));
+       }
+       return start;
+}
+
+/*
+ * extract key that was previously encoded by build_inode_onwire() at @addr
+ */
+char *extract_obj_key_id_from_onwire(char *addr, obj_key_id * key_id)
+{
+       __u64 val;
+
+       addr += dscale_read(addr, &val);
+       val = (val << KEY_LOCALITY_SHIFT) | KEY_SD_MINOR;
+       put_unaligned(cpu_to_le64(val), (__le64 *)key_id->locality);
+       addr += dscale_read(addr, &val);
+       put_unaligned(cpu_to_le64(val), (__le64 *)key_id->objectid);
+#if REISER4_LARGE_KEY
+       memcpy(&key_id->ordering, addr, sizeof key_id->ordering);
+       addr += sizeof key_id->ordering;
+#endif
+       return addr;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/kassign.h linux-2.6.20/fs/reiser4/kassign.h
--- linux-2.6.20.orig/fs/reiser4/kassign.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/kassign.h   2007-05-06 14:50:43.734986973 +0400
@@ -0,0 +1,110 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Key assignment policy interface. See kassign.c for details. */
+
+#if !defined( __KASSIGN_H__ )
+#define __KASSIGN_H__
+
+#include "forward.h"
+#include "key.h"
+#include "dformat.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block, etc  */
+#include <linux/dcache.h>      /* for struct qstr */
+
+/* key assignment functions */
+
+/* Information from which key of file stat-data can be uniquely
+   restored. This depends on key assignment policy for
+   stat-data. Currently it's enough to store object id and locality id
+   (60+60==120) bits, because minor packing locality and offset of
+   stat-data key are always known constants: KEY_SD_MINOR and 0
+   respectively. For simplicity 4 bits are wasted in each id, and just
+   two 64 bit integers are stored.
+
+   This field has to be byte-aligned, because we don't want to waste
+   space in directory entries. There is another side of a coin of
+   course: we waste CPU and bus bandwidth in stead, by copying data back
+   and forth.
+
+   Next optimization: &obj_key_id is mainly used to address stat data from
+   directory entries. Under the assumption that majority of files only have
+   only name (one hard link) from *the* parent directory it seems reasonable
+   to only store objectid of stat data and take its locality from key of
+   directory item.
+
+   This requires some flag to be added to the &obj_key_id to distinguish
+   between these two cases. Remaining bits in flag byte are then asking to be
+   used to store file type.
+
+   This optimization requires changes in directory item handling code.
+
+*/
+typedef struct obj_key_id {
+       d8 locality[sizeof(__u64)];
+        ON_LARGE_KEY(d8 ordering[sizeof(__u64)];
+           )
+       d8 objectid[sizeof(__u64)];
+}
+obj_key_id;
+
+/* Information sufficient to uniquely identify directory entry within
+   compressed directory item.
+
+   For alignment issues see &obj_key_id above.
+*/
+typedef struct de_id {
+       ON_LARGE_KEY(d8 ordering[sizeof(__u64)];)
+       d8 objectid[sizeof(__u64)];
+       d8 offset[sizeof(__u64)];
+}
+de_id;
+
+extern int inode_onwire_size(const struct inode *obj);
+extern char *build_inode_onwire(const struct inode *obj, char *area);
+extern char *extract_obj_key_id_from_onwire(char *area, obj_key_id * key_id);
+
+extern int build_inode_key_id(const struct inode *obj, obj_key_id * id);
+extern int extract_key_from_id(const obj_key_id * id, reiser4_key * key);
+extern int build_obj_key_id(const reiser4_key * key, obj_key_id * id);
+extern oid_t extract_dir_id_from_key(const reiser4_key * de_key);
+extern int build_de_id(const struct inode *dir, const struct qstr *name,
+                      de_id * id);
+extern int build_de_id_by_key(const reiser4_key * entry_key, de_id * id);
+extern int extract_key_from_de_id(const oid_t locality, const de_id * id,
+                                 reiser4_key * key);
+extern cmp_t de_id_cmp(const de_id * id1, const de_id * id2);
+extern cmp_t de_id_key_cmp(const de_id * id, const reiser4_key * key);
+
+extern int build_readdir_key_common(struct file *dir, reiser4_key * result);
+extern void build_entry_key_common(const struct inode *dir,
+                                  const struct qstr *name,
+                                  reiser4_key * result);
+extern void build_entry_key_stable_entry(const struct inode *dir,
+                                        const struct qstr *name,
+                                        reiser4_key * result);
+extern int is_dot_key(const reiser4_key * key);
+extern reiser4_key *build_sd_key(const struct inode *target,
+                                reiser4_key * result);
+
+extern int is_longname_key(const reiser4_key * key);
+extern int is_longname(const char *name, int len);
+extern char *extract_name_from_key(const reiser4_key * key, char *buf);
+extern char *reiser4_unpack_string(__u64 value, char *buf);
+extern void complete_entry_key(const struct inode *dir, const char *name,
+                              int len, reiser4_key *result);
+
+/* __KASSIGN_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/Kconfig linux-2.6.20/fs/reiser4/Kconfig
--- linux-2.6.20.orig/fs/reiser4/Kconfig        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/Kconfig     2007-05-06 14:50:43.734986973 +0400
@@ -0,0 +1,32 @@
+config REISER4_FS
+       tristate "Reiser4 (EXPERIMENTAL)"
+       depends on EXPERIMENTAL
+       select ZLIB_INFLATE
+       select ZLIB_DEFLATE
+       select CRYPTO
+       help
+         Reiser4 is a filesystem that performs all filesystem operations
+         as atomic transactions, which means that it either performs a
+         write, or it does not, and in the event of a crash it does not
+         partially perform it or corrupt it.
+
+         It stores files in dancing trees, which are like balanced trees but
+         faster.  It packs small files together so that they share blocks
+         without wasting space.  This means you can use it to store really
+         small files.  It also means that it saves you disk space.  It avoids
+         hassling you with anachronisms like having a maximum number of
+         inodes, and wasting space if you use less than that number.
+
+         Reiser4 is a distinct filesystem type from reiserfs (V3).
+         It's therefore not possible to use reiserfs file systems
+         with reiser4.
+
+         To learn more about reiser4, go to http://www.namesys.com
+
+config REISER4_DEBUG
+       bool "Enable reiser4 debug mode"
+       depends on REISER4_FS
+       help
+         Don't use this unless you are debugging reiser4.
+
+         If unsure, say N.
diff -urN linux-2.6.20.orig/fs/reiser4/key.c linux-2.6.20/fs/reiser4/key.c
--- linux-2.6.20.orig/fs/reiser4/key.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/key.c       2007-05-06 14:50:43.734986973 +0400
@@ -0,0 +1,137 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Key manipulations. */
+
+#include "debug.h"
+#include "key.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/types.h>       /* for __u??  */
+
+/* Minimal possible key: all components are zero. It is presumed that this is
+   independent of key scheme. */
+static const reiser4_key MINIMAL_KEY = {
+       .el = {
+               0ull,
+               ON_LARGE_KEY(0ull,)
+               0ull,
+               0ull
+       }
+};
+
+/* Maximal possible key: all components are ~0. It is presumed that this is
+   independent of key scheme. */
+static const reiser4_key MAXIMAL_KEY = {
+       .el = {
+               __constant_cpu_to_le64(~0ull),
+               ON_LARGE_KEY(__constant_cpu_to_le64(~0ull),)
+               __constant_cpu_to_le64(~0ull),
+               __constant_cpu_to_le64(~0ull)
+       }
+};
+
+/* Initialize key. */
+void reiser4_key_init(reiser4_key * key /* key to init */ )
+{
+       assert("nikita-1169", key != NULL);
+       memset(key, 0, sizeof *key);
+}
+
+/* minimal possible key in the tree. Return pointer to the static storage. */
+const reiser4_key *reiser4_min_key(void)
+{
+       return &MINIMAL_KEY;
+}
+
+/* maximum possible key in the tree. Return pointer to the static storage. */
+const reiser4_key *reiser4_max_key(void)
+{
+       return &MAXIMAL_KEY;
+}
+
+#if REISER4_DEBUG
+/* debugging aid: print symbolic name of key type */
+static const char *type_name(unsigned int key_type /* key type */ )
+{
+       switch (key_type) {
+       case KEY_FILE_NAME_MINOR:
+               return "file name";
+       case KEY_SD_MINOR:
+               return "stat data";
+       case KEY_ATTR_NAME_MINOR:
+               return "attr name";
+       case KEY_ATTR_BODY_MINOR:
+               return "attr body";
+       case KEY_BODY_MINOR:
+               return "file body";
+       default:
+               return "unknown";
+       }
+}
+
+/* debugging aid: print human readable information about key */
+void reiser4_print_key(const char *prefix /* prefix to print */ ,
+              const reiser4_key * key /* key to print */ )
+{
+       /* turn bold on */
+       /* printf ("\033[1m"); */
+       if (key == NULL)
+               printk("%s: null key\n", prefix);
+       else {
+               if (REISER4_LARGE_KEY)
+                       printk("%s: (%Lx:%x:%Lx:%Lx:%Lx:%Lx)", prefix,
+                              get_key_locality(key),
+                              get_key_type(key),
+                              get_key_ordering(key),
+                              get_key_band(key),
+                              get_key_objectid(key), get_key_offset(key));
+               else
+                       printk("%s: (%Lx:%x:%Lx:%Lx:%Lx)", prefix,
+                              get_key_locality(key),
+                              get_key_type(key),
+                              get_key_band(key),
+                              get_key_objectid(key), get_key_offset(key));
+               /*
+                * if this is a key of directory entry, try to decode part of
+                * a name stored in the key, and output it.
+                */
+               if (get_key_type(key) == KEY_FILE_NAME_MINOR) {
+                       char buf[DE_NAME_BUF_LEN];
+                       char *c;
+
+                       c = buf;
+                       c = reiser4_unpack_string(get_key_ordering(key), c);
+                       reiser4_unpack_string(get_key_fulloid(key), c);
+                       printk("[%s", buf);
+                       if (is_longname_key(key))
+                               /*
+                                * only part of the name is stored in the key.
+                                */
+                               printk("...]\n");
+                       else {
+                               /*
+                                * whole name is stored in the key.
+                                */
+                               reiser4_unpack_string(get_key_offset(key), buf);
+                               printk("%s]\n", buf);
+                       }
+               } else {
+                       printk("[%s]\n", type_name(get_key_type(key)));
+               }
+       }
+       /* turn bold off */
+       /* printf ("\033[m\017"); */
+}
+
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/key.h linux-2.6.20/fs/reiser4/key.h
--- linux-2.6.20.orig/fs/reiser4/key.h  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/key.h       2007-05-06 14:50:43.738988223 +0400
@@ -0,0 +1,384 @@
+/* Copyright 2000, 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Declarations of key-related data-structures and operations on keys. */
+
+#if !defined( __REISER4_KEY_H__ )
+#define __REISER4_KEY_H__
+
+#include "dformat.h"
+#include "forward.h"
+#include "debug.h"
+
+#include <linux/types.h>       /* for __u??  */
+
+/* Operations on keys in reiser4 tree */
+
+/* No access to any of these fields shall be done except via a
+   wrapping macro/function, and that wrapping macro/function shall
+   convert to little endian order.  Compare keys will consider cpu byte order. */
+
+/* A storage layer implementation difference between a regular unix file body and its attributes is in the typedef below
+   which causes all of the attributes of a file to be near in key to all of the other attributes for all of the files
+   within that directory, and not near to the file itself.  It is interesting to consider whether this is the wrong
+   approach, and whether there should be no difference at all. For current usage patterns this choice is probably the
+   right one.  */
+
+/* possible values for minor packing locality (4 bits required) */
+typedef enum {
+       /* file name */
+       KEY_FILE_NAME_MINOR = 0,
+       /* stat-data */
+       KEY_SD_MINOR = 1,
+       /* file attribute name */
+       KEY_ATTR_NAME_MINOR = 2,
+       /* file attribute value */
+       KEY_ATTR_BODY_MINOR = 3,
+       /* file body (tail or extent) */
+       KEY_BODY_MINOR = 4,
+} key_minor_locality;
+
+/* everything stored in the tree has a unique key, which means that the tree is (logically) fully ordered by key.
+   Physical order is determined by dynamic heuristics that attempt to reflect key order when allocating available space,
+   and by the repacker.  It is stylistically better to put aggregation information into the key.  Thus, if you want to
+   segregate extents from tails, it is better to give them distinct minor packing localities rather than changing
+   block_alloc.c to check the node type when deciding where to allocate the node.
+
+   The need to randomly displace new directories and large files disturbs this symmetry unfortunately.  However, it
+   should be noted that this is a need that is not clearly established given the existence of a repacker.  Also, in our
+   current implementation tails have a different minor packing locality from extents, and no files have both extents and
+   tails, so maybe symmetry can be had without performance cost after all.  Symmetry is what we ship for now....
+*/
+
+/* Arbitrary major packing localities can be assigned to objects using
+   the reiser4(filenameA/..packing<=some_number) system call.
+
+   In reiser4, the creat() syscall creates a directory
+
+   whose default flow (that which is referred to if the directory is
+   read as a file) is the traditional unix file body.
+
+   whose directory plugin is the 'filedir'
+
+   whose major packing locality is that of the parent of the object created.
+
+   The static_stat item is a particular commonly used directory
+   compression (the one for normal unix files).
+
+   The filedir plugin checks to see if the static_stat item exists.
+   There is a unique key for static_stat.  If yes, then it uses the
+   static_stat item for all of the values that it contains.  The
+   static_stat item contains a flag for each stat it contains which
+   indicates whether one should look outside the static_stat item for its
+   contents.
+*/
+
+/* offset of fields in reiser4_key. Value of each element of this enum
+    is index within key (thought as array of __u64's) where this field
+    is. */
+typedef enum {
+       /* major "locale", aka dirid. Sits in 1st element */
+       KEY_LOCALITY_INDEX = 0,
+       /* minor "locale", aka item type. Sits in 1st element */
+       KEY_TYPE_INDEX = 0,
+       ON_LARGE_KEY(KEY_ORDERING_INDEX,)
+           /* "object band". Sits in 2nd element */
+           KEY_BAND_INDEX,
+       /* objectid. Sits in 2nd element */
+       KEY_OBJECTID_INDEX = KEY_BAND_INDEX,
+       /* full objectid. Sits in 2nd element */
+       KEY_FULLOID_INDEX = KEY_BAND_INDEX,
+       /* Offset. Sits in 3rd element */
+       KEY_OFFSET_INDEX,
+       /* Name hash. Sits in 3rd element */
+       KEY_HASH_INDEX = KEY_OFFSET_INDEX,
+       KEY_CACHELINE_END = KEY_OFFSET_INDEX,
+       KEY_LAST_INDEX
+} reiser4_key_field_index;
+
+/* key in reiser4 internal "balanced" tree. It is just array of three
+    64bit integers in disk byte order (little-endian by default). This
+    array is actually indexed by reiser4_key_field.  Each __u64 within
+    this array is called "element". Logical key component encoded within
+    elements are called "fields".
+
+    We declare this as union with second component dummy to suppress
+    inconvenient array<->pointer casts implied in C. */
+union reiser4_key {
+       __le64 el[KEY_LAST_INDEX];
+       int pad;
+};
+
+/* bitmasks showing where within reiser4_key particular key is stored. */
+/* major locality occupies higher 60 bits of the first element */
+#define KEY_LOCALITY_MASK 0xfffffffffffffff0ull
+
+/* minor locality occupies lower 4 bits of the first element */
+#define KEY_TYPE_MASK 0xfull
+
+/* controversial band occupies higher 4 bits of the 2nd element */
+#define KEY_BAND_MASK 0xf000000000000000ull
+
+/* objectid occupies lower 60 bits of the 2nd element */
+#define KEY_OBJECTID_MASK 0x0fffffffffffffffull
+
+/* full 64bit objectid*/
+#define KEY_FULLOID_MASK 0xffffffffffffffffull
+
+/* offset is just 3rd L.M.Nt itself */
+#define KEY_OFFSET_MASK 0xffffffffffffffffull
+
+/* ordering is whole second element */
+#define KEY_ORDERING_MASK 0xffffffffffffffffull
+
+/* how many bits key element should be shifted to left to get particular field */
+typedef enum {
+       KEY_LOCALITY_SHIFT = 4,
+       KEY_TYPE_SHIFT = 0,
+       KEY_BAND_SHIFT = 60,
+       KEY_OBJECTID_SHIFT = 0,
+       KEY_FULLOID_SHIFT = 0,
+       KEY_OFFSET_SHIFT = 0,
+       KEY_ORDERING_SHIFT = 0,
+} reiser4_key_field_shift;
+
+static inline __u64
+get_key_el(const reiser4_key * key, reiser4_key_field_index off)
+{
+       assert("nikita-753", key != NULL);
+       assert("nikita-754", off < KEY_LAST_INDEX);
+       return le64_to_cpu(get_unaligned(&key->el[off]));
+}
+
+static inline void
+set_key_el(reiser4_key * key, reiser4_key_field_index off, __u64 value)
+{
+       assert("nikita-755", key != NULL);
+       assert("nikita-756", off < KEY_LAST_INDEX);
+       put_unaligned(cpu_to_le64(value), &key->el[off]);
+}
+
+/* macro to define getter and setter functions for field F with type T */
+#define DEFINE_KEY_FIELD( L, U, T )                                    \
+static inline T get_key_ ## L ( const reiser4_key *key )               \
+{                                                                      \
+       assert( "nikita-750", key != NULL );                            \
+       return ( T ) ( get_key_el( key, KEY_ ## U ## _INDEX ) &         \
+                KEY_ ## U ## _MASK ) >> KEY_ ## U ## _SHIFT;           \
+}                                                                      \
+                                                                       \
+static inline void set_key_ ## L ( reiser4_key *key, T loc )           \
+{                                                                      \
+       __u64 el;                                                       \
+                                                                       \
+       assert( "nikita-752", key != NULL );                            \
+                                                                       \
+       el = get_key_el( key, KEY_ ## U ## _INDEX );                    \
+       /* clear field bits in the key */                               \
+       el &= ~KEY_ ## U ## _MASK;                                      \
+       /* actually it should be                                        \
+                                                                       \
+          el |= ( loc << KEY_ ## U ## _SHIFT ) & KEY_ ## U ## _MASK;   \
+                                                                       \
+          but we trust user to never pass values that wouldn't fit     \
+          into field. Clearing extra bits is one operation, but this   \
+          function is time-critical.                                   \
+          But check this in assertion. */                              \
+       assert( "nikita-759", ( ( loc << KEY_ ## U ## _SHIFT ) &        \
+               ~KEY_ ## U ## _MASK ) == 0 );                           \
+       el |= ( loc << KEY_ ## U ## _SHIFT );                           \
+       set_key_el( key, KEY_ ## U ## _INDEX, el );                     \
+}
+
+typedef __u64 oid_t;
+
+/* define get_key_locality(), set_key_locality() */
+DEFINE_KEY_FIELD(locality, LOCALITY, oid_t);
+/* define get_key_type(), set_key_type() */
+DEFINE_KEY_FIELD(type, TYPE, key_minor_locality);
+/* define get_key_band(), set_key_band() */
+DEFINE_KEY_FIELD(band, BAND, __u64);
+/* define get_key_objectid(), set_key_objectid() */
+DEFINE_KEY_FIELD(objectid, OBJECTID, oid_t);
+/* define get_key_fulloid(), set_key_fulloid() */
+DEFINE_KEY_FIELD(fulloid, FULLOID, oid_t);
+/* define get_key_offset(), set_key_offset() */
+DEFINE_KEY_FIELD(offset, OFFSET, __u64);
+#if (REISER4_LARGE_KEY)
+/* define get_key_ordering(), set_key_ordering() */
+DEFINE_KEY_FIELD(ordering, ORDERING, __u64);
+#else
+static inline __u64 get_key_ordering(const reiser4_key * key)
+{
+       return 0;
+}
+
+static inline void set_key_ordering(reiser4_key * key, __u64 val)
+{
+}
+#endif
+
+/* key comparison result */
+typedef enum { LESS_THAN = -1, /* if first key is less than second */
+       EQUAL_TO = 0,           /* if keys are equal */
+       GREATER_THAN = +1       /* if first key is greater than second */
+} cmp_t;
+
+void reiser4_key_init(reiser4_key * key);
+
+/* minimal possible key in the tree. Return pointer to the static storage. */
+extern const reiser4_key *reiser4_min_key(void);
+extern const reiser4_key *reiser4_max_key(void);
+
+/* helper macro for keycmp() */
+#define KEY_DIFF(k1, k2, field)                                                        \
+({                                                                             \
+       typeof (get_key_ ## field (k1)) f1;                                     \
+       typeof (get_key_ ## field (k2)) f2;                                     \
+                                                                               \
+       f1 = get_key_ ## field (k1);                                            \
+       f2 = get_key_ ## field (k2);                                            \
+                                                                               \
+       (f1 < f2) ? LESS_THAN : ((f1 == f2) ? EQUAL_TO : GREATER_THAN);         \
+})
+
+/* helper macro for keycmp() */
+#define KEY_DIFF_EL(k1, k2, off)                                               \
+({                                                                             \
+       __u64 e1;                                                               \
+       __u64 e2;                                                               \
+                                                                               \
+       e1 = get_key_el(k1, off);                                               \
+       e2 = get_key_el(k2, off);                                               \
+                                                                               \
+       (e1 < e2) ? LESS_THAN : ((e1 == e2) ? EQUAL_TO : GREATER_THAN);         \
+})
+
+/* compare `k1' and `k2'.  This function is a heart of "key allocation
+    policy". All you need to implement new policy is to add yet another
+    clause here. */
+static inline cmp_t keycmp(const reiser4_key * k1 /* first key to compare */ ,
+                          const reiser4_key * k2 /* second key to compare */ )
+{
+       cmp_t result;
+
+       /*
+        * This function is the heart of reiser4 tree-routines. Key comparison
+        * is among most heavily used operations in the file system.
+        */
+
+       assert("nikita-439", k1 != NULL);
+       assert("nikita-440", k2 != NULL);
+
+       /* there is no actual branch here: condition is compile time constant
+        * and constant folding and propagation ensures that only one branch
+        * is actually compiled in. */
+
+       if (REISER4_PLANA_KEY_ALLOCATION) {
+               /* if physical order of fields in a key is identical
+                  with logical order, we can implement key comparison
+                  as three 64bit comparisons. */
+               /* logical order of fields in plan-a:
+                  locality->type->objectid->offset. */
+               /* compare locality and type at once */
+               result = KEY_DIFF_EL(k1, k2, 0);
+               if (result == EQUAL_TO) {
+                       /* compare objectid (and band if it's there) */
+                       result = KEY_DIFF_EL(k1, k2, 1);
+                       /* compare offset */
+                       if (result == EQUAL_TO) {
+                               result = KEY_DIFF_EL(k1, k2, 2);
+                               if (REISER4_LARGE_KEY && result == EQUAL_TO) {
+                                       result = KEY_DIFF_EL(k1, k2, 3);
+                               }
+                       }
+               }
+       } else if (REISER4_3_5_KEY_ALLOCATION) {
+               result = KEY_DIFF(k1, k2, locality);
+               if (result == EQUAL_TO) {
+                       result = KEY_DIFF(k1, k2, objectid);
+                       if (result == EQUAL_TO) {
+                               result = KEY_DIFF(k1, k2, type);
+                               if (result == EQUAL_TO)
+                                       result = KEY_DIFF(k1, k2, offset);
+                       }
+               }
+       } else
+               impossible("nikita-441", "Unknown key allocation scheme!");
+       return result;
+}
+
+/* true if @k1 equals @k2 */
+static inline int keyeq(const reiser4_key * k1 /* first key to compare */ ,
+                       const reiser4_key * k2 /* second key to compare */ )
+{
+       assert("nikita-1879", k1 != NULL);
+       assert("nikita-1880", k2 != NULL);
+       return !memcmp(k1, k2, sizeof *k1);
+}
+
+/* true if @k1 is less than @k2 */
+static inline int keylt(const reiser4_key * k1 /* first key to compare */ ,
+                       const reiser4_key * k2 /* second key to compare */ )
+{
+       assert("nikita-1952", k1 != NULL);
+       assert("nikita-1953", k2 != NULL);
+       return keycmp(k1, k2) == LESS_THAN;
+}
+
+/* true if @k1 is less than or equal to @k2 */
+static inline int keyle(const reiser4_key * k1 /* first key to compare */ ,
+                       const reiser4_key * k2 /* second key to compare */ )
+{
+       assert("nikita-1954", k1 != NULL);
+       assert("nikita-1955", k2 != NULL);
+       return keycmp(k1, k2) != GREATER_THAN;
+}
+
+/* true if @k1 is greater than @k2 */
+static inline int keygt(const reiser4_key * k1 /* first key to compare */ ,
+                       const reiser4_key * k2 /* second key to compare */ )
+{
+       assert("nikita-1959", k1 != NULL);
+       assert("nikita-1960", k2 != NULL);
+       return keycmp(k1, k2) == GREATER_THAN;
+}
+
+/* true if @k1 is greater than or equal to @k2 */
+static inline int keyge(const reiser4_key * k1 /* first key to compare */ ,
+                       const reiser4_key * k2 /* second key to compare */ )
+{
+       assert("nikita-1956", k1 != NULL);
+       assert("nikita-1957", k2 != NULL);      /* October  4: sputnik launched
+                                                * November 3: Laika */
+       return keycmp(k1, k2) != LESS_THAN;
+}
+
+static inline void prefetchkey(reiser4_key * key)
+{
+       prefetch(key);
+       prefetch(&key->el[KEY_CACHELINE_END]);
+}
+
+/* (%Lx:%x:%Lx:%Lx:%Lx:%Lx) =
+           1 + 16 + 1 + 1 + 1 + 1 + 1 + 16 + 1 + 16 + 1 + 16 + 1 */
+/* size of a buffer suitable to hold human readable key representation */
+#define KEY_BUF_LEN (80)
+
+#if REISER4_DEBUG
+extern void reiser4_print_key(const char *prefix, const reiser4_key * key);
+#else
+#define reiser4_print_key(p,k) noop
+#endif
+
+/* __FS_REISERFS_KEY_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/ktxnmgrd.c linux-2.6.20/fs/reiser4/ktxnmgrd.c
--- linux-2.6.20.orig/fs/reiser4/ktxnmgrd.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/ktxnmgrd.c  2007-05-06 14:50:43.738988223 +0400
@@ -0,0 +1,215 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* Transaction manager daemon. */
+
+/*
+ * ktxnmgrd is a kernel daemon responsible for committing transactions. It is
+ * needed/important for the following reasons:
+ *
+ *     1. in reiser4 atom is not committed immediately when last transaction
+ *     handle closes, unless atom is either too old or too large (see
+ *     atom_should_commit()). This is done to avoid committing too frequently.
+ *     because:
+ *
+ *     2. sometimes we don't want to commit atom when closing last transaction
+ *     handle even if it is old and fat enough. For example, because we are at
+ *     this point under directory semaphore, and committing would stall all
+ *     accesses to this directory.
+ *
+ * ktxnmgrd binds its time sleeping on condition variable. When is awakes
+ * either due to (tunable) timeout or because it was explicitly woken up by
+ * call to ktxnmgrd_kick(), it scans list of all atoms and commits ones
+ * eligible.
+ *
+ */
+
+#include "debug.h"
+#include "txnmgr.h"
+#include "tree.h"
+#include "ktxnmgrd.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/sched.h>       /* for struct task_struct */
+#include <linux/wait.h>
+#include <linux/suspend.h>
+#include <linux/kernel.h>
+#include <linux/writeback.h>
+#include <linux/kthread.h>
+#include <linux/freezer.h>
+
+static int scan_mgr(struct super_block *);
+
+/*
+ * change current->comm so that ps, top, and friends will see changed
+ * state. This serves no useful purpose whatsoever, but also costs nothing. May
+ * be it will make lonely system administrator feeling less alone at 3 A.M.
+ */
+#define set_comm( state )                                              \
+       snprintf( current -> comm, sizeof( current -> comm ),   \
+                 "%s:%s:%s", __FUNCTION__, (super)->s_id, ( state ) )
+
+/**
+ * ktxnmgrd - kernel txnmgr daemon
+ * @arg: pointer to super block
+ *
+ * The background transaction manager daemon, started as a kernel thread during
+ * reiser4 initialization.
+ */
+static int ktxnmgrd(void *arg)
+{
+       struct super_block *super;
+       ktxnmgrd_context *ctx;
+       txn_mgr *mgr;
+       int done = 0;
+
+       super = arg;
+       mgr = &get_super_private(super)->tmgr;
+
+       /*
+        * do_fork() just copies task_struct into the new thread. ->fs_context
+        * shouldn't be copied of course. This shouldn't be a problem for the
+        * rest of the code though.
+        */
+       current->journal_info = NULL;
+       ctx = mgr->daemon;
+       while (1) {
+               try_to_freeze();
+               set_comm("wait");
+               {
+                       DEFINE_WAIT(__wait);
+
+                       prepare_to_wait(&ctx->wait, &__wait, TASK_INTERRUPTIBLE);
+                       if (kthread_should_stop()) {
+                               done = 1;
+                       } else
+                               schedule_timeout(ctx->timeout);
+                       finish_wait(&ctx->wait, &__wait);
+               }
+               if (done)
+                       break;
+               set_comm("run");
+               spin_lock(&ctx->guard);
+               /*
+                * wait timed out or ktxnmgrd was woken up by explicit request
+                * to commit something. Scan list of atoms in txnmgr and look
+                * for too old atoms.
+                */
+               do {
+                       ctx->rescan = 0;
+                       scan_mgr(super);
+                       spin_lock(&ctx->guard);
+                       if (ctx->rescan) {
+                               /*
+                                * the list could be modified while ctx
+                                * spinlock was released, we have to repeat
+                                * scanning from the beginning
+                                */
+                               break;
+                       }
+               } while (ctx->rescan);
+               spin_unlock(&ctx->guard);
+       }
+       return 0;
+}
+
+#undef set_comm
+
+/**
+ * reiser4_init_ktxnmgrd - initialize ktxnmgrd context and start kernel daemon
+ * @super: pointer to super block
+ *
+ * Allocates and initializes ktxnmgrd_context, attaches it to transaction
+ * manager. Starts kernel txnmgr daemon. This is called on mount.
+ */
+int reiser4_init_ktxnmgrd(struct super_block *super)
+{
+       txn_mgr *mgr;
+       ktxnmgrd_context *ctx;
+
+       mgr = &get_super_private(super)->tmgr;
+
+       assert("zam-1014", mgr->daemon == NULL);
+
+       ctx = kmalloc(sizeof(ktxnmgrd_context), reiser4_ctx_gfp_mask_get());
+       if (ctx == NULL)
+               return RETERR(-ENOMEM);
+
+       assert("nikita-2442", ctx != NULL);
+
+       memset(ctx, 0, sizeof *ctx);
+       init_waitqueue_head(&ctx->wait);
+
+       /*kcond_init(&ctx->startup);*/
+       spin_lock_init(&ctx->guard);
+       ctx->timeout = REISER4_TXNMGR_TIMEOUT;
+       ctx->rescan = 1;
+       mgr->daemon = ctx;
+
+       ctx->tsk = kthread_run(ktxnmgrd, super, "ktxnmgrd");
+       if (IS_ERR(ctx->tsk)) {
+               int ret = PTR_ERR(ctx->tsk);
+               mgr->daemon = NULL;
+               kfree(ctx);
+               return RETERR(ret);
+       }
+       return 0;
+}
+
+void ktxnmgrd_kick(txn_mgr *mgr)
+{
+       assert("nikita-3234", mgr != NULL);
+       assert("nikita-3235", mgr->daemon != NULL);
+       wake_up(&mgr->daemon->wait);
+}
+
+int is_current_ktxnmgrd(void)
+{
+       return (get_current_super_private()->tmgr.daemon->tsk == current);
+}
+
+/**
+ * scan_mgr - commit atoms which are to be committed
+ * @super: super block to commit atoms of
+ *
+ * Commits old atoms.
+ */
+static int scan_mgr(struct super_block *super)
+{
+       int ret;
+       reiser4_context ctx;
+
+       init_stack_context(&ctx, super);
+
+       ret = commit_some_atoms(&get_super_private(super)->tmgr);
+
+       reiser4_exit_context(&ctx);
+       return ret;
+}
+
+/**
+ * reiser4_done_ktxnmgrd - stop kernel thread and frees ktxnmgrd context
+ * @mgr:
+ *
+ * This is called on umount. Stops ktxnmgrd and free t
+ */
+void reiser4_done_ktxnmgrd(struct super_block *super)
+{
+       txn_mgr *mgr;
+
+       mgr = &get_super_private(super)->tmgr;
+       assert("zam-1012", mgr->daemon != NULL);
+
+       kthread_stop(mgr->daemon->tsk);
+       kfree(mgr->daemon);
+       mgr->daemon = NULL;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/ktxnmgrd.h linux-2.6.20/fs/reiser4/ktxnmgrd.h
--- linux-2.6.20.orig/fs/reiser4/ktxnmgrd.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/ktxnmgrd.h  2007-05-06 14:50:43.738988223 +0400
@@ -0,0 +1,52 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Transaction manager daemon. See ktxnmgrd.c for comments. */
+
+#ifndef __KTXNMGRD_H__
+#define __KTXNMGRD_H__
+
+#include "txnmgr.h"
+
+#include <linux/fs.h>
+#include <linux/wait.h>
+#include <linux/completion.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <linux/sched.h>       /* for struct task_struct */
+
+/* in this structure all data necessary to start up, shut down and communicate
+ * with ktxnmgrd are kept. */
+struct ktxnmgrd_context {
+       /* wait queue head on which ktxnmgrd sleeps */
+       wait_queue_head_t wait;
+       /* spin lock protecting all fields of this structure */
+       spinlock_t guard;
+       /* timeout of sleeping on ->wait */
+       signed long timeout;
+       /* kernel thread running ktxnmgrd */
+       struct task_struct *tsk;
+       /* list of all file systems served by this ktxnmgrd */
+       struct list_head queue;
+       /* should ktxnmgrd repeat scanning of atoms? */
+       unsigned int rescan:1;
+};
+
+extern int reiser4_init_ktxnmgrd(struct super_block *);
+extern void reiser4_done_ktxnmgrd(struct super_block *);
+
+extern void ktxnmgrd_kick(txn_mgr * mgr);
+extern int is_current_ktxnmgrd(void);
+
+/* __KTXNMGRD_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/lock.c linux-2.6.20/fs/reiser4/lock.c
--- linux-2.6.20.orig/fs/reiser4/lock.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/lock.c      2007-05-06 14:50:43.742989473 +0400
@@ -0,0 +1,1232 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Traditional deadlock avoidance is achieved by acquiring all locks in a single
+   order.  V4 balances the tree from the bottom up, and searches the tree from
+   the top down, and that is really the way we want it, so tradition won't work
+   for us.
+
+   Instead we have two lock orderings, a high priority lock ordering, and a low
+   priority lock ordering.  Each node in the tree has a lock in its znode.
+
+   Suppose we have a set of processes which lock (R/W) tree nodes. Each process
+   has a set (maybe empty) of already locked nodes ("process locked set"). Each
+   process may have a pending lock request to a node locked by another process.
+   Note: we lock and unlock, but do not transfer locks: it is possible
+   transferring locks instead would save some bus locking....
+
+   Deadlock occurs when we have a loop constructed from process locked sets and
+   lock request vectors.
+
+   NOTE: The reiser4 "tree" is a tree on disk, but its cached representation in
+   memory is extended with "znodes" with which we connect nodes with their left
+   and right neighbors using sibling pointers stored in the znodes.  When we
+   perform balancing operations we often go from left to right and from right to
+   left.
+
+   +-P1-+          +-P3-+
+   |+--+|   V1     |+--+|
+   ||N1|| -------> ||N3||
+   |+--+|          |+--+|
+   +----+          +----+
+     ^               |
+     |V2             |V3
+     |               v
+   +---------P2---------+
+   |+--+            +--+|
+   ||N2|  --------  |N4||
+   |+--+            +--+|
+   +--------------------+
+
+   We solve this by ensuring that only low priority processes lock in top to
+   bottom order and from right to left, and high priority processes lock from
+   bottom to top and left to right.
+
+   ZAM-FIXME-HANS: order not just node locks in this way, order atom locks, and
+   kill those damn busy loops.
+   ANSWER(ZAM): atom locks (which are introduced by ASTAGE_CAPTURE_WAIT atom
+   stage) cannot be ordered that way. There are no rules what nodes can belong
+   to the atom and what nodes cannot.  We cannot define what is right or left
+   direction, what is top or bottom.  We can take immediate parent or side
+   neighbor of one node, but nobody guarantees that, say, left neighbor node is
+   not a far right neighbor for other nodes from the same atom.  It breaks
+   deadlock avoidance rules and hi-low priority locking cannot be applied for
+   atom locks.
+
+   How does it help to avoid deadlocks ?
+
+   Suppose we have a deadlock with n processes. Processes from one priority
+   class never deadlock because they take locks in one consistent
+   order.
+
+   So, any possible deadlock loop must have low priority as well as high
+   priority processes.  There are no other lock priority levels except low and
+   high. We know that any deadlock loop contains at least one node locked by a
+   low priority process and requested by a high priority process. If this
+   situation is caught and resolved it is sufficient to avoid deadlocks.
+
+   V4 DEADLOCK PREVENTION ALGORITHM IMPLEMENTATION.
+
+   The deadlock prevention algorithm is based on comparing
+   priorities of node owners (processes which keep znode locked) and
+   requesters (processes which want to acquire a lock on znode).  We
+   implement a scheme where low-priority owners yield locks to
+   high-priority requesters. We created a signal passing system that
+   is used to ask low-priority processes to yield one or more locked
+   znodes.
+
+   The condition when a znode needs to change its owners is described by the
+   following formula:
+
+   #############################################
+   #                                           #
+   # (number of high-priority requesters) >  0 #
+   #                AND                        #
+   # (numbers of high-priority owners)    == 0 #
+   #                                           #
+   #############################################
+
+   Note that a low-priority process delays node releasing if another
+   high-priority process owns this node.  So, slightly more strictly speaking,
+   to have a deadlock capable cycle you must have a loop in which a high
+   priority process is waiting on a low priority process to yield a node, which
+   is slightly different from saying a high priority process is waiting on a
+   node owned by a low priority process.
+
+   It is enough to avoid deadlocks if we prevent any low-priority process from
+   falling asleep if its locked set contains a node which satisfies the
+   deadlock condition.
+
+   That condition is implicitly or explicitly checked in all places where new
+   high-priority requests may be added or removed from node request queue or
+   high-priority process takes or releases a lock on node. The main
+   goal of these checks is to never lose the moment when node becomes "has
+   wrong owners" and send "must-yield-this-lock" signals to its low-pri owners
+   at that time.
+
+   The information about received signals is stored in the per-process
+   structure (lock stack) and analyzed before a low-priority process goes to
+   sleep but after a "fast" attempt to lock a node fails. Any signal wakes
+   sleeping process up and forces him to re-check lock status and received
+   signal info. If "must-yield-this-lock" signals were received the locking
+   primitive (longterm_lock_znode()) fails with -E_DEADLOCK error code.
+
+   V4 LOCKING DRAWBACKS
+
+   If we have already balanced on one level, and we are propagating our changes
+   upward to a higher level, it could be very messy to surrender all locks on
+   the lower level because we put so much computational work into it, and
+   reverting them to their state before they were locked might be very complex.
+   We also don't want to acquire all locks before performing balancing because
+   that would either be almost as much work as the balancing, or it would be
+   too conservative and lock too much.  We want balancing to be done only at
+   high priority.  Yet, we might want to go to the left one node and use some
+   of its empty space... So we make one attempt at getting the node to the left
+   using try_lock, and if it fails we do without it, because we didn't really
+   need it, it was only a nice to have.
+
+   LOCK STRUCTURES DESCRIPTION
+
+   The following data structures are used in the reiser4 locking
+   implementation:
+
+   All fields related to long-term locking are stored in znode->lock.
+
+   The lock stack is a per thread object.  It owns all znodes locked by the
+   thread. One znode may be locked by several threads in case of read lock or
+   one znode may be write locked by one thread several times. The special link
+   objects (lock handles) support n<->m relation between znodes and lock
+   owners.
+
+   <Thread 1>                       <Thread 2>
+
+   +---------+                     +---------+
+   |  LS1    |                    |  LS2    |
+   +---------+                    +---------+
+       ^                                ^
+       |---------------+                +----------+
+       v               v                v          v
+   +---------+      +---------+    +---------+   +---------+
+   |  LH1    |      |   LH2   |           |  LH3    |   |   LH4   |
+   +---------+     +---------+    +---------+   +---------+
+       ^                   ^            ^           ^
+       |                   +------------+           |
+       v                   v                        v
+   +---------+      +---------+                  +---------+
+   |  Z1     |     |   Z2    |                  |  Z3     |
+   +---------+     +---------+                  +---------+
+
+   Thread 1 locked znodes Z1 and Z2, thread 2 locked znodes Z2 and Z3. The
+   picture above shows that lock stack LS1 has a list of 2 lock handles LH1 and
+   LH2, lock stack LS2 has a list with lock handles LH3 and LH4 on it.  Znode
+   Z1 is locked by only one thread, znode has only one lock handle LH1 on its
+   list, similar situation is for Z3 which is locked by the thread 2 only. Z2
+   is locked (for read) twice by different threads and two lock handles are on
+   its list. Each lock handle represents a single relation of a locking of a
+   znode by a thread. Locking of a znode is an establishing of a locking
+   relation between the lock stack and the znode by adding of a new lock handle
+   to a list of lock handles, the lock stack.  The lock stack links all lock
+   handles for all znodes locked by the lock stack.  The znode list groups all
+   lock handles for all locks stacks which locked the znode.
+
+   Yet another relation may exist between znode and lock owners.  If lock
+   procedure cannot immediately take lock on an object it adds the lock owner
+   on special `requestors' list belongs to znode.  That list represents a
+   queue of pending lock requests.  Because one lock owner may request only
+   only one lock object at a time, it is a 1->n relation between lock objects
+   and a lock owner implemented as it is described above. Full information
+   (priority, pointers to lock and link objects) about each lock request is
+   stored in lock owner structure in `request' field.
+
+   SHORT_TERM LOCKING
+
+   This is a list of primitive operations over lock stacks / lock handles /
+   znodes and locking descriptions for them.
+
+   1. locking / unlocking which is done by two list insertion/deletion, one
+      to/from znode's list of lock handles, another one is to/from lock stack's
+      list of lock handles.  The first insertion is protected by
+      znode->lock.guard spinlock.  The list owned by the lock stack can be
+      modified only by thread who owns the lock stack and nobody else can
+      modify/read it. There is nothing to be protected by a spinlock or
+      something else.
+
+   2. adding/removing a lock request to/from znode requesters list. The rule is
+      that znode->lock.guard spinlock should be taken for this.
+
+   3. we can traverse list of lock handles and use references to lock stacks who
+      locked given znode if znode->lock.guard spinlock is taken.
+
+   4. If a lock stack is associated with a znode as a lock requestor or lock
+      owner its existence is guaranteed by znode->lock.guard spinlock.  Some its
+      (lock stack's) fields should be protected from being accessed in parallel
+      by two or more threads. Please look at  lock_stack structure definition
+      for the info how those fields are protected. */
+
+/* Znode lock and capturing intertwining. */
+/* In current implementation we capture formatted nodes before locking
+   them. Take a look on longterm lock znode, reiser4_try_capture() request
+   precedes locking requests.  The longterm_lock_znode function unconditionally
+   captures znode before even checking of locking conditions.
+
+   Another variant is to capture znode after locking it.  It was not tested, but
+   at least one deadlock condition is supposed to be there.  One thread has
+   locked a znode (Node-1) and calls reiser4_try_capture() for it.
+   reiser4_try_capture() sleeps because znode's atom has CAPTURE_WAIT state.
+   Second thread is a flushing thread, its current atom is the atom Node-1
+   belongs to. Second thread wants to lock Node-1 and sleeps because Node-1
+   is locked by the first thread.  The described situation is a deadlock. */
+
+#include "debug.h"
+#include "txnmgr.h"
+#include "znode.h"
+#include "jnode.h"
+#include "tree.h"
+#include "plugin/node/node.h"
+#include "super.h"
+
+#include <linux/spinlock.h>
+
+#if REISER4_DEBUG
+static int request_is_deadlock_safe(znode *, znode_lock_mode,
+                                   znode_lock_request);
+#endif
+
+/* Returns a lock owner associated with current thread */
+lock_stack *get_current_lock_stack(void)
+{
+       return &get_current_context()->stack;
+}
+
+/* Wakes up all low priority owners informing them about possible deadlock */
+static void wake_up_all_lopri_owners(znode * node)
+{
+       lock_handle *handle;
+
+       assert_spin_locked(&(node->lock.guard));
+       list_for_each_entry(handle, &node->lock.owners, owners_link) {
+               assert("nikita-1832", handle->node == node);
+               /* count this signal in owner->nr_signaled */
+               if (!handle->signaled) {
+                       handle->signaled = 1;
+                       atomic_inc(&handle->owner->nr_signaled);
+                       /* Wake up a single process */
+                       reiser4_wake_up(handle->owner);
+               }
+       }
+}
+
+/* Adds a lock to a lock owner, which means creating a link to the lock and
+   putting the link into the two lists all links are on (the doubly linked list
+   that forms the lock_stack, and the doubly linked list of links attached
+   to a lock.
+*/
+static inline void
+link_object(lock_handle * handle, lock_stack * owner, znode * node)
+{
+       assert("jmacd-810", handle->owner == NULL);
+       assert_spin_locked(&(node->lock.guard));
+
+       handle->owner = owner;
+       handle->node = node;
+
+       assert("reiser4-4",
+              ergo(list_empty_careful(&owner->locks), owner->nr_locks == 0));
+
+       /* add lock handle to the end of lock_stack's list of locks */
+       list_add_tail(&handle->locks_link, &owner->locks);
+       ON_DEBUG(owner->nr_locks++);
+       reiser4_ctx_gfp_mask_set();
+
+       /* add lock handle to the head of znode's list of owners */
+       list_add(&handle->owners_link, &node->lock.owners);
+       handle->signaled = 0;
+}
+
+/* Breaks a relation between a lock and its owner */
+static inline void unlink_object(lock_handle * handle)
+{
+       assert("zam-354", handle->owner != NULL);
+       assert("nikita-1608", handle->node != NULL);
+       assert_spin_locked(&(handle->node->lock.guard));
+       assert("nikita-1829", handle->owner == get_current_lock_stack());
+       assert("reiser4-5", handle->owner->nr_locks > 0);
+
+       /* remove lock handle from lock_stack's list of locks */
+       list_del(&handle->locks_link);
+       ON_DEBUG(handle->owner->nr_locks--);
+       reiser4_ctx_gfp_mask_set();
+       assert("reiser4-6",
+              ergo(list_empty_careful(&handle->owner->locks),
+                   handle->owner->nr_locks == 0));
+       /* remove lock handle from znode's list of owners */
+       list_del(&handle->owners_link);
+       /* indicates that lock handle is free now */
+       handle->node = NULL;
+#if REISER4_DEBUG
+       INIT_LIST_HEAD(&handle->locks_link);
+       INIT_LIST_HEAD(&handle->owners_link);
+       handle->owner = NULL;
+#endif
+}
+
+/* Actually locks an object knowing that we are able to do this */
+static void lock_object(lock_stack * owner)
+{
+       lock_request *request;
+       znode *node;
+
+       request = &owner->request;
+       node = request->node;
+       assert_spin_locked(&(node->lock.guard));
+       if (request->mode == ZNODE_READ_LOCK) {
+               node->lock.nr_readers++;
+       } else {
+               /* check that we don't switched from read to write lock */
+               assert("nikita-1840", node->lock.nr_readers <= 0);
+               /* We allow recursive locking; a node can be locked several
+                  times for write by same process */
+               node->lock.nr_readers--;
+       }
+
+       link_object(request->handle, owner, node);
+
+       if (owner->curpri) {
+               node->lock.nr_hipri_owners++;
+       }
+}
+
+/* Check for recursive write locking */
+static int recursive(lock_stack * owner)
+{
+       int ret;
+       znode *node;
+       lock_handle *lh;
+
+       node = owner->request.node;
+
+       /* Owners list is not empty for a locked node */
+       assert("zam-314", !list_empty_careful(&node->lock.owners));
+       assert("nikita-1841", owner == get_current_lock_stack());
+       assert_spin_locked(&(node->lock.guard));
+
+       lh = list_entry(node->lock.owners.next, lock_handle, owners_link);
+       ret = (lh->owner == owner);
+
+       /* Recursive read locking should be done usual way */
+       assert("zam-315", !ret || owner->request.mode == ZNODE_WRITE_LOCK);
+       /* mixing of read/write locks is not allowed */
+       assert("zam-341", !ret || znode_is_wlocked(node));
+
+       return ret;
+}
+
+#if REISER4_DEBUG
+/* Returns true if the lock is held by the calling thread. */
+int znode_is_any_locked(const znode * node)
+{
+       lock_handle *handle;
+       lock_stack *stack;
+       int ret;
+
+       if (!znode_is_locked(node)) {
+               return 0;
+       }
+
+       stack = get_current_lock_stack();
+
+       spin_lock_stack(stack);
+
+       ret = 0;
+
+       list_for_each_entry(handle, &stack->locks, locks_link) {
+               if (handle->node == node) {
+                       ret = 1;
+                       break;
+               }
+       }
+
+       spin_unlock_stack(stack);
+
+       return ret;
+}
+
+#endif
+
+/* Returns true if a write lock is held by the calling thread. */
+int znode_is_write_locked(const znode * node)
+{
+       lock_stack *stack;
+       lock_handle *handle;
+
+       assert("jmacd-8765", node != NULL);
+
+       if (!znode_is_wlocked(node)) {
+               return 0;
+       }
+
+       stack = get_current_lock_stack();
+
+       /*
+        * When znode is write locked, all owner handles point to the same lock
+        * stack. Get pointer to lock stack from the first lock handle from
+        * znode's owner list
+        */
+       handle = list_entry(node->lock.owners.next, lock_handle, owners_link);
+
+       return (handle->owner == stack);
+}
+
+/* This "deadlock" condition is the essential part of reiser4 locking
+   implementation. This condition is checked explicitly by calling
+   check_deadlock_condition() or implicitly in all places where znode lock
+   state (set of owners and request queue) is changed. Locking code is
+   designed to use this condition to trigger procedure of passing object from
+   low priority owner(s) to high priority one(s).
+
+   The procedure results in passing an event (setting lock_handle->signaled
+   flag) and counting this event in nr_signaled field of owner's lock stack
+   object and wakeup owner's process.
+*/
+static inline int check_deadlock_condition(znode * node)
+{
+       assert_spin_locked(&(node->lock.guard));
+       return node->lock.nr_hipri_requests > 0
+           && node->lock.nr_hipri_owners == 0;
+}
+
+static int check_livelock_condition(znode * node, znode_lock_mode mode)
+{
+       zlock * lock = &node->lock;
+
+       return mode == ZNODE_READ_LOCK &&
+               lock -> nr_readers >= 0 && lock->nr_hipri_write_requests > 0;
+}
+
+/* checks lock/request compatibility */
+static int can_lock_object(lock_stack * owner)
+{
+       znode *node = owner->request.node;
+
+       assert_spin_locked(&(node->lock.guard));
+
+       /* See if the node is disconnected. */
+       if (unlikely(ZF_ISSET(node, JNODE_IS_DYING)))
+               return RETERR(-EINVAL);
+
+       /* Do not ever try to take a lock if we are going in low priority
+          direction and a node have a high priority request without high
+          priority owners. */
+       if (unlikely(!owner->curpri && check_deadlock_condition(node)))
+               return RETERR(-E_REPEAT);
+       if (unlikely(owner->curpri && check_livelock_condition(node, owner->request.mode)))
+               return RETERR(-E_REPEAT);
+       if (unlikely(!is_lock_compatible(node, owner->request.mode)))
+               return RETERR(-E_REPEAT);
+       return 0;
+}
+
+/* Setting of a high priority to the process. It clears "signaled" flags
+   because znode locked by high-priority process can't satisfy our "deadlock
+   condition". */
+static void set_high_priority(lock_stack * owner)
+{
+       assert("nikita-1846", owner == get_current_lock_stack());
+       /* Do nothing if current priority is already high */
+       if (!owner->curpri) {
+               /* We don't need locking for owner->locks list, because, this
+                * function is only called with the lock stack of the current
+                * thread, and no other thread can play with owner->locks list
+                * and/or change ->node pointers of lock handles in this list.
+                *
+                * (Interrupts also are not involved.)
+                */
+               lock_handle *item = list_entry(owner->locks.next, lock_handle, locks_link);
+               while (&owner->locks != &item->locks_link) {
+                       znode *node = item->node;
+
+                       spin_lock_zlock(&node->lock);
+
+                       node->lock.nr_hipri_owners++;
+
+                       /* we can safely set signaled to zero, because
+                          previous statement (nr_hipri_owners ++) guarantees
+                          that signaled will be never set again. */
+                       item->signaled = 0;
+                       spin_unlock_zlock(&node->lock);
+
+                       item = list_entry(item->locks_link.next, lock_handle, locks_link);
+               }
+               owner->curpri = 1;
+               atomic_set(&owner->nr_signaled, 0);
+       }
+}
+
+/* Sets a low priority to the process. */
+static void set_low_priority(lock_stack * owner)
+{
+       assert("nikita-3075", owner == get_current_lock_stack());
+       /* Do nothing if current priority is already low */
+       if (owner->curpri) {
+               /* scan all locks (lock handles) held by @owner, which is
+                  actually current thread, and check whether we are reaching
+                  deadlock possibility anywhere.
+                */
+               lock_handle *handle = list_entry(owner->locks.next, lock_handle, locks_link);
+               while (&owner->locks != &handle->locks_link) {
+                       znode *node = handle->node;
+                       spin_lock_zlock(&node->lock);
+                       /* this thread just was hipri owner of @node, so
+                          nr_hipri_owners has to be greater than zero. */
+                       assert("nikita-1835", node->lock.nr_hipri_owners > 0);
+                       node->lock.nr_hipri_owners--;
+                       /* If we have deadlock condition, adjust a nr_signaled
+                          field. It is enough to set "signaled" flag only for
+                          current process, other low-pri owners will be
+                          signaled and waken up after current process unlocks
+                          this object and any high-priority requestor takes
+                          control. */
+                       if (check_deadlock_condition(node)
+                           && !handle->signaled) {
+                               handle->signaled = 1;
+                               atomic_inc(&owner->nr_signaled);
+                       }
+                       spin_unlock_zlock(&node->lock);
+                       handle = list_entry(handle->locks_link.next, lock_handle, locks_link);
+               }
+               owner->curpri = 0;
+       }
+}
+
+static void remove_lock_request(lock_stack * requestor)
+{
+       zlock * lock = &requestor->request.node->lock;
+
+       if (requestor->curpri) {
+               assert("nikita-1838", lock->nr_hipri_requests > 0);
+               lock->nr_hipri_requests--;
+               if (requestor->request.mode == ZNODE_WRITE_LOCK)
+                       lock->nr_hipri_write_requests --;
+       }
+       list_del(&requestor->requestors_link);
+}
+
+static void invalidate_all_lock_requests(znode * node)
+{
+       lock_stack *requestor, *tmp;
+
+       assert_spin_locked(&(node->lock.guard));
+
+       list_for_each_entry_safe(requestor, tmp, &node->lock.requestors, requestors_link) {
+               remove_lock_request(requestor);
+               requestor->request.ret_code = -EINVAL;
+               reiser4_wake_up(requestor);
+               requestor->request.mode = ZNODE_NO_LOCK;
+       }
+}
+
+static void dispatch_lock_requests(znode * node)
+{
+       lock_stack *requestor, *tmp;
+
+       assert_spin_locked(&(node->lock.guard));
+
+       list_for_each_entry_safe(requestor, tmp, &node->lock.requestors, requestors_link) {
+               if (znode_is_write_locked(node))
+                       break;
+               if (!can_lock_object(requestor)) {
+                       lock_object(requestor);
+                       remove_lock_request(requestor);
+                       requestor->request.ret_code = 0;
+                       reiser4_wake_up(requestor);
+                       requestor->request.mode = ZNODE_NO_LOCK;
+               }
+       }
+}
+
+/* release long-term lock, acquired by longterm_lock_znode() */
+void longterm_unlock_znode(lock_handle * handle)
+{
+       znode *node = handle->node;
+       lock_stack *oldowner = handle->owner;
+       int hipri;
+       int readers;
+       int rdelta;
+       int youdie;
+
+       /*
+        * this is time-critical and highly optimized code. Modify carefully.
+        */
+
+       assert("jmacd-1021", handle != NULL);
+       assert("jmacd-1022", handle->owner != NULL);
+       assert("nikita-1392", LOCK_CNT_GTZ(long_term_locked_znode));
+
+       assert("zam-130", oldowner == get_current_lock_stack());
+
+       LOCK_CNT_DEC(long_term_locked_znode);
+
+       /*
+        * to minimize amount of operations performed under lock, pre-compute
+        * all variables used within critical section. This makes code
+        * obscure.
+        */
+
+       /* was this lock of hi or lo priority */
+       hipri = oldowner->curpri ? 1 : 0;
+       /* number of readers */
+       readers = node->lock.nr_readers;
+       /* +1 if write lock, -1 if read lock */
+       rdelta = (readers > 0) ? -1 : +1;
+       /* true if node is to die and write lock is released */
+       youdie = ZF_ISSET(node, JNODE_HEARD_BANSHEE) && (readers < 0);
+
+       spin_lock_zlock(&node->lock);
+
+       assert("zam-101", znode_is_locked(node));
+
+       /* Adjust a number of high priority owners of this lock */
+       assert("nikita-1836", node->lock.nr_hipri_owners >= hipri);
+       node->lock.nr_hipri_owners -= hipri;
+
+       /* Handle znode deallocation on last write-lock release. */
+       if (znode_is_wlocked_once(node)) {
+               if (youdie) {
+                       forget_znode(handle);
+                       assert("nikita-2191", znode_invariant(node));
+                       zput(node);
+                       return;
+               }
+       }
+
+       if (handle->signaled)
+               atomic_dec(&oldowner->nr_signaled);
+
+       /* Unlocking means owner<->object link deletion */
+       unlink_object(handle);
+
+       /* This is enough to be sure whether an object is completely
+          unlocked. */
+       node->lock.nr_readers += rdelta;
+
+       /* If the node is locked it must have an owners list.  Likewise, if
+          the node is unlocked it must have an empty owners list. */
+       assert("zam-319", equi(znode_is_locked(node),
+                              !list_empty_careful(&node->lock.owners)));
+
+#if REISER4_DEBUG
+       if (!znode_is_locked(node))
+               ++node->times_locked;
+#endif
+
+       /* If there are pending lock requests we wake up a requestor */
+       if (!znode_is_wlocked(node))
+               dispatch_lock_requests(node);
+       if (check_deadlock_condition(node))
+               wake_up_all_lopri_owners(node);
+       spin_unlock_zlock(&node->lock);
+
+       /* minus one reference from handle->node */
+       assert("nikita-2190", znode_invariant(node));
+       ON_DEBUG(check_lock_data());
+       ON_DEBUG(check_lock_node_data(node));
+       zput(node);
+}
+
+/* final portion of longterm-lock */
+static int
+lock_tail(lock_stack * owner, int ok, znode_lock_mode mode)
+{
+       znode *node = owner->request.node;
+
+       assert_spin_locked(&(node->lock.guard));
+
+       /* If we broke with (ok == 0) it means we can_lock, now do it. */
+       if (ok == 0) {
+               lock_object(owner);
+               owner->request.mode = 0;
+               /* count a reference from lockhandle->node
+
+                  znode was already referenced at the entry to this function,
+                  hence taking spin-lock here is not necessary (see comment
+                  in the zref()).
+                */
+               zref(node);
+
+               LOCK_CNT_INC(long_term_locked_znode);
+       }
+       spin_unlock_zlock(&node->lock);
+       ON_DEBUG(check_lock_data());
+       ON_DEBUG(check_lock_node_data(node));
+       return ok;
+}
+
+/*
+ * version of longterm_znode_lock() optimized for the most common case: read
+ * lock without any special flags. This is the kind of lock that any tree
+ * traversal takes on the root node of the tree, which is very frequent.
+ */
+static int longterm_lock_tryfast(lock_stack * owner)
+{
+       int result;
+       znode *node;
+       zlock *lock;
+
+       node = owner->request.node;
+       lock = &node->lock;
+
+       assert("nikita-3340", reiser4_schedulable());
+       assert("nikita-3341", request_is_deadlock_safe(node,
+                                                      ZNODE_READ_LOCK,
+                                                      ZNODE_LOCK_LOPRI));
+       spin_lock_zlock(lock);
+       result = can_lock_object(owner);
+       spin_unlock_zlock(lock);
+
+       if (likely(result != -EINVAL)) {
+               spin_lock_znode(node);
+               result = reiser4_try_capture(ZJNODE(node), ZNODE_READ_LOCK, 0);
+               spin_unlock_znode(node);
+               spin_lock_zlock(lock);
+               if (unlikely(result != 0)) {
+                       owner->request.mode = 0;
+               } else {
+                       result = can_lock_object(owner);
+                       if (unlikely(result == -E_REPEAT)) {
+                               /* fall back to longterm_lock_znode() */
+                               spin_unlock_zlock(lock);
+                               return 1;
+                       }
+               }
+               return lock_tail(owner, result, ZNODE_READ_LOCK);
+       } else
+               return 1;
+}
+
+/* locks given lock object */
+int longterm_lock_znode(
+                              /* local link object (allocated by lock owner thread, usually on its own
+                               * stack) */
+                              lock_handle * handle,
+                              /* znode we want to lock. */
+                              znode * node,
+                              /* {ZNODE_READ_LOCK, ZNODE_WRITE_LOCK}; */
+                              znode_lock_mode mode,
+                              /* {0, -EINVAL, -E_DEADLOCK}, see return codes description. */
+                              znode_lock_request request) {
+       int ret;
+       int hipri = (request & ZNODE_LOCK_HIPRI) != 0;
+       int non_blocking = 0;
+       int has_atom;
+       txn_capture cap_flags;
+       zlock *lock;
+       txn_handle *txnh;
+       tree_level level;
+
+       /* Get current process context */
+       lock_stack *owner = get_current_lock_stack();
+
+       /* Check that the lock handle is initialized and isn't already being
+        * used. */
+       assert("jmacd-808", handle->owner == NULL);
+       assert("nikita-3026", reiser4_schedulable());
+       assert("nikita-3219", request_is_deadlock_safe(node, mode, request));
+       assert("zam-1056", atomic_read(&ZJNODE(node)->x_count) > 0);
+       /* long term locks are not allowed in the VM contexts (->writepage(),
+        * prune_{d,i}cache()).
+        *
+        * FIXME this doesn't work due to unused-dentry-with-unlinked-inode
+        * bug caused by d_splice_alias() only working for directories.
+        */
+       assert("nikita-3547", 1 || ((current->flags & PF_MEMALLOC) == 0));
+       assert ("zam-1055", mode != ZNODE_NO_LOCK);
+
+       cap_flags = 0;
+       if (request & ZNODE_LOCK_NONBLOCK) {
+               cap_flags |= TXN_CAPTURE_NONBLOCKING;
+               non_blocking = 1;
+       }
+
+       if (request & ZNODE_LOCK_DONT_FUSE)
+               cap_flags |= TXN_CAPTURE_DONT_FUSE;
+
+       /* If we are changing our process priority we must adjust a number
+          of high priority owners for each znode that we already lock */
+       if (hipri) {
+               set_high_priority(owner);
+       } else {
+               set_low_priority(owner);
+       }
+
+       level = znode_get_level(node);
+
+       /* Fill request structure with our values. */
+       owner->request.mode = mode;
+       owner->request.handle = handle;
+       owner->request.node = node;
+
+       txnh = get_current_context()->trans;
+       lock = &node->lock;
+
+       if (mode == ZNODE_READ_LOCK && request == 0) {
+               ret = longterm_lock_tryfast(owner);
+               if (ret <= 0)
+                       return ret;
+       }
+
+       has_atom = (txnh->atom != NULL);
+
+       /* Synchronize on node's zlock guard lock. */
+       spin_lock_zlock(lock);
+
+       if (znode_is_locked(node) &&
+           mode == ZNODE_WRITE_LOCK && recursive(owner))
+               return lock_tail(owner, 0, mode);
+
+       for (;;) {
+               /* Check the lock's availability: if it is unavaiable we get
+                  E_REPEAT, 0 indicates "can_lock", otherwise the node is
+                  invalid.  */
+               ret = can_lock_object(owner);
+
+               if (unlikely(ret == -EINVAL)) {
+                       /* @node is dying. Leave it alone. */
+                       break;
+               }
+
+               if (unlikely(ret == -E_REPEAT && non_blocking)) {
+                       /* either locking of @node by the current thread will
+                        * lead to the deadlock, or lock modes are
+                        * incompatible. */
+                       break;
+               }
+
+               assert("nikita-1844", (ret == 0)
+                      || ((ret == -E_REPEAT) && !non_blocking));
+               /* If we can get the lock... Try to capture first before
+                  taking the lock. */
+
+               /* first handle commonest case where node and txnh are already
+                * in the same atom. */
+               /* safe to do without taking locks, because:
+                *
+                * 1. read of aligned word is atomic with respect to writes to
+                * this word
+                *
+                * 2. false negatives are handled in reiser4_try_capture().
+                *
+                * 3. false positives are impossible.
+                *
+                * PROOF: left as an exercise to the curious reader.
+                *
+                * Just kidding. Here is one:
+                *
+                * At the time T0 txnh->atom is stored in txnh_atom.
+                *
+                * At the time T1 node->atom is stored in node_atom.
+                *
+                * At the time T2 we observe that
+                *
+                *     txnh_atom != NULL && node_atom == txnh_atom.
+                *
+                * Imagine that at this moment we acquire node and txnh spin
+                * lock in this order. Suppose that under spin lock we have
+                *
+                *     node->atom != txnh->atom,                       (S1)
+                *
+                * at the time T3.
+                *
+                * txnh->atom != NULL still, because txnh is open by the
+                * current thread.
+                *
+                * Suppose node->atom == NULL, that is, node was un-captured
+                * between T1, and T3. But un-capturing of formatted node is
+                * always preceded by the call to reiser4_invalidate_lock(),
+                * which marks znode as JNODE_IS_DYING under zlock spin
+                * lock. Contradiction, because can_lock_object() above checks
+                * for JNODE_IS_DYING. Hence, node->atom != NULL at T3.
+                *
+                * Suppose that node->atom != node_atom, that is, atom, node
+                * belongs to was fused into another atom: node_atom was fused
+                * into node->atom. Atom of txnh was equal to node_atom at T2,
+                * which means that under spin lock, txnh->atom == node->atom,
+                * because txnh->atom can only follow fusion
+                * chain. Contradicts S1.
+                *
+                * The same for hypothesis txnh->atom != txnh_atom. Hence,
+                * node->atom == node_atom == txnh_atom == txnh->atom. Again
+                * contradicts S1. Hence S1 is false. QED.
+                *
+                */
+
+               if (likely(has_atom && ZJNODE(node)->atom == txnh->atom)) {
+                       ;
+               } else {
+                       /*
+                        * unlock zlock spin lock here. It is possible for
+                        * longterm_unlock_znode() to sneak in here, but there
+                        * is no harm: reiser4_invalidate_lock() will mark znode
+                        * as JNODE_IS_DYING and this will be noted by
+                        * can_lock_object() below.
+                        */
+                       spin_unlock_zlock(lock);
+                       spin_lock_znode(node);
+                       ret = reiser4_try_capture(ZJNODE(node), mode, cap_flags);
+                       spin_unlock_znode(node);
+                       spin_lock_zlock(lock);
+                       if (unlikely(ret != 0)) {
+                               /* In the failure case, the txnmgr releases
+                                  the znode's lock (or in some cases, it was
+                                  released a while ago).  There's no need to
+                                  reacquire it so we should return here,
+                                  avoid releasing the lock. */
+                               owner->request.mode = 0;
+                               break;
+                       }
+
+                       /* Check the lock's availability again -- this is
+                          because under some circumstances the capture code
+                          has to release and reacquire the znode spinlock. */
+                       ret = can_lock_object(owner);
+               }
+
+               /* This time, a return of (ret == 0) means we can lock, so we
+                  should break out of the loop. */
+               if (likely(ret != -E_REPEAT || non_blocking))
+                       break;
+
+               /* Lock is unavailable, we have to wait. */
+               ret = reiser4_prepare_to_sleep(owner);
+               if (unlikely(ret != 0))
+                       break;
+
+               assert_spin_locked(&(node->lock.guard));
+               if (hipri) {
+                       /* If we are going in high priority direction then
+                          increase high priority requests counter for the
+                          node */
+                       lock->nr_hipri_requests++;
+                       if (mode == ZNODE_WRITE_LOCK)
+                               lock->nr_hipri_write_requests ++;
+                       /* If there are no high priority owners for a node,
+                          then immediately wake up low priority owners, so
+                          they can detect possible deadlock */
+                       if (lock->nr_hipri_owners == 0)
+                               wake_up_all_lopri_owners(node);
+               }
+               list_add_tail(&owner->requestors_link, &lock->requestors);
+
+               /* Ok, here we have prepared a lock request, so unlock
+                  a znode ... */
+               spin_unlock_zlock(lock);
+               /* ... and sleep */
+               reiser4_go_to_sleep(owner);
+               if (owner->request.mode == ZNODE_NO_LOCK)
+                       goto request_is_done;
+               spin_lock_zlock(lock);
+               if (owner->request.mode == ZNODE_NO_LOCK) {
+                       spin_unlock_zlock(lock);
+               request_is_done:
+                       if (owner->request.ret_code == 0) {
+                               LOCK_CNT_INC(long_term_locked_znode);
+                               zref(node);
+                       }
+                       return owner->request.ret_code;
+               }
+               remove_lock_request(owner);
+       }
+
+       return lock_tail(owner, ret, mode);
+}
+
+/* lock object invalidation means changing of lock object state to `INVALID'
+   and waiting for all other processes to cancel theirs lock requests. */
+void reiser4_invalidate_lock(lock_handle * handle      /* path to lock
+                                                        * owner and lock
+                                                        * object is being
+                                                        * invalidated. */ )
+{
+       znode *node = handle->node;
+       lock_stack *owner = handle->owner;
+
+       assert("zam-325", owner == get_current_lock_stack());
+       assert("zam-103", znode_is_write_locked(node));
+       assert("nikita-1393", !ZF_ISSET(node, JNODE_LEFT_CONNECTED));
+       assert("nikita-1793", !ZF_ISSET(node, JNODE_RIGHT_CONNECTED));
+       assert("nikita-1394", ZF_ISSET(node, JNODE_HEARD_BANSHEE));
+       assert("nikita-3097", znode_is_wlocked_once(node));
+       assert_spin_locked(&(node->lock.guard));
+
+       if (handle->signaled)
+               atomic_dec(&owner->nr_signaled);
+
+       ZF_SET(node, JNODE_IS_DYING);
+       unlink_object(handle);
+       node->lock.nr_readers = 0;
+
+       invalidate_all_lock_requests(node);
+       spin_unlock_zlock(&node->lock);
+}
+
+/* Initializes lock_stack. */
+void init_lock_stack(lock_stack * owner        /* pointer to
+                                        * allocated
+                                        * structure. */ )
+{
+       INIT_LIST_HEAD(&owner->locks);
+       INIT_LIST_HEAD(&owner->requestors_link);
+       spin_lock_init(&owner->sguard);
+       owner->curpri = 1;
+       init_waitqueue_head(&owner->wait);
+}
+
+/* Initializes lock object. */
+void reiser4_init_lock(zlock * lock    /* pointer on allocated
+                                        * uninitialized lock object
+                                        * structure. */ )
+{
+       memset(lock, 0, sizeof(zlock));
+       spin_lock_init(&lock->guard);
+       INIT_LIST_HEAD(&lock->requestors);
+       INIT_LIST_HEAD(&lock->owners);
+}
+
+/* Transfer a lock handle (presumably so that variables can be moved between stack and
+   heap locations). */
+static void
+move_lh_internal(lock_handle * new, lock_handle * old, int unlink_old)
+{
+       znode *node = old->node;
+       lock_stack *owner = old->owner;
+       int signaled;
+
+       /* locks_list, modified by link_object() is not protected by
+          anything. This is valid because only current thread ever modifies
+          locks_list of its lock_stack.
+        */
+       assert("nikita-1827", owner == get_current_lock_stack());
+       assert("nikita-1831", new->owner == NULL);
+
+       spin_lock_zlock(&node->lock);
+
+       signaled = old->signaled;
+       if (unlink_old) {
+               unlink_object(old);
+       } else {
+               if (node->lock.nr_readers > 0) {
+                       node->lock.nr_readers += 1;
+               } else {
+                       node->lock.nr_readers -= 1;
+               }
+               if (signaled) {
+                       atomic_inc(&owner->nr_signaled);
+               }
+               if (owner->curpri) {
+                       node->lock.nr_hipri_owners += 1;
+               }
+               LOCK_CNT_INC(long_term_locked_znode);
+
+               zref(node);
+       }
+       link_object(new, owner, node);
+       new->signaled = signaled;
+
+       spin_unlock_zlock(&node->lock);
+}
+
+void move_lh(lock_handle * new, lock_handle * old)
+{
+       move_lh_internal(new, old, /*unlink_old */ 1);
+}
+
+void copy_lh(lock_handle * new, lock_handle * old)
+{
+       move_lh_internal(new, old, /*unlink_old */ 0);
+}
+
+/* after getting -E_DEADLOCK we unlock znodes until this function returns false */
+int reiser4_check_deadlock(void)
+{
+       lock_stack *owner = get_current_lock_stack();
+       return atomic_read(&owner->nr_signaled) != 0;
+}
+
+/* Before going to sleep we re-check "release lock" requests which might come from threads with hi-pri lock
+   priorities. */
+int reiser4_prepare_to_sleep(lock_stack * owner)
+{
+       assert("nikita-1847", owner == get_current_lock_stack());
+
+       /* We return -E_DEADLOCK if one or more "give me the lock" messages are
+        * counted in nr_signaled */
+       if (unlikely(atomic_read(&owner->nr_signaled) != 0)) {
+               assert("zam-959", !owner->curpri);
+               return RETERR(-E_DEADLOCK);
+       }
+       return 0;
+}
+
+/* Wakes up a single thread */
+void __reiser4_wake_up(lock_stack * owner)
+{
+       atomic_set(&owner->wakeup, 1);
+       wake_up(&owner->wait);
+}
+
+/* Puts a thread to sleep */
+void reiser4_go_to_sleep(lock_stack * owner)
+{
+       /* Well, we might sleep here, so holding of any spinlocks is no-no */
+       assert("nikita-3027", reiser4_schedulable());
+
+       wait_event(owner->wait, atomic_read(&owner->wakeup));
+       atomic_set(&owner->wakeup, 0);
+}
+
+int lock_stack_isclean(lock_stack * owner)
+{
+       if (list_empty_careful(&owner->locks)) {
+               assert("zam-353", atomic_read(&owner->nr_signaled) == 0);
+               return 1;
+       }
+
+       return 0;
+}
+
+#if REISER4_DEBUG
+
+/*
+ * debugging functions
+ */
+
+static void list_check(struct list_head *head)
+{
+       struct list_head *pos;
+
+       list_for_each(pos, head)
+               assert("", (pos->prev != NULL && pos->next != NULL &&
+                           pos->prev->next == pos && pos->next->prev == pos));
+}
+
+/* check consistency of locking data-structures hanging of the @stack */
+static void check_lock_stack(lock_stack * stack)
+{
+       spin_lock_stack(stack);
+       /* check that stack->locks is not corrupted */
+       list_check(&stack->locks);
+       spin_unlock_stack(stack);
+}
+
+/* check consistency of locking data structures */
+void check_lock_data(void)
+{
+       check_lock_stack(&get_current_context()->stack);
+}
+
+/* check consistency of locking data structures for @node */
+void check_lock_node_data(znode * node)
+{
+       spin_lock_zlock(&node->lock);
+       list_check(&node->lock.owners);
+       list_check(&node->lock.requestors);
+       spin_unlock_zlock(&node->lock);
+}
+
+/* check that given lock request is dead lock safe. This check is, of course,
+ * not exhaustive. */
+static int
+request_is_deadlock_safe(znode * node, znode_lock_mode mode,
+                        znode_lock_request request)
+{
+       lock_stack *owner;
+
+       owner = get_current_lock_stack();
+       /*
+        * check that hipri lock request is not issued when there are locked
+        * nodes at the higher levels.
+        */
+       if (request & ZNODE_LOCK_HIPRI && !(request & ZNODE_LOCK_NONBLOCK) &&
+           znode_get_level(node) != 0) {
+               lock_handle *item;
+
+               list_for_each_entry(item, &owner->locks, locks_link) {
+                       znode *other;
+
+                       other = item->node;
+
+                       if (znode_get_level(other) == 0)
+                               continue;
+                       if (znode_get_level(other) > znode_get_level(node))
+                               return 0;
+               }
+       }
+       return 1;
+}
+
+#endif
+
+/* return pointer to static storage with name of lock_mode. For
+    debugging */
+const char *lock_mode_name(znode_lock_mode lock /* lock mode to get name of */ )
+{
+       if (lock == ZNODE_READ_LOCK)
+               return "read";
+       else if (lock == ZNODE_WRITE_LOCK)
+               return "write";
+       else {
+               static char buf[30];
+
+               sprintf(buf, "unknown: %i", lock);
+               return buf;
+       }
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 79
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/lock.h linux-2.6.20/fs/reiser4/lock.h
--- linux-2.6.20.orig/fs/reiser4/lock.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/lock.h      2007-05-06 14:50:43.742989473 +0400
@@ -0,0 +1,249 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Long term locking data structures. See lock.c for details. */
+
+#ifndef __LOCK_H__
+#define __LOCK_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/node/node.h"
+#include "txnmgr.h"
+#include "readahead.h"
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/pagemap.h>     /* for PAGE_CACHE_SIZE */
+#include <asm/atomic.h>
+#include <linux/wait.h>
+
+/* Per-znode lock object */
+struct zlock {
+       spinlock_t guard;
+       /* The number of readers if positive; the number of recursively taken
+          write locks if negative. Protected by zlock spin lock. */
+       int nr_readers;
+       /* A number of processes (lock_stacks) that have this object
+          locked with high priority */
+       unsigned nr_hipri_owners;
+       /* A number of attempts to lock znode in high priority direction */
+       unsigned nr_hipri_requests;
+       /* A linked list of lock_handle objects that contains pointers
+          for all lock_stacks which have this lock object locked */
+       unsigned nr_hipri_write_requests;
+       struct list_head owners;
+       /* A linked list of lock_stacks that wait for this lock */
+       struct list_head requestors;
+};
+
+static inline void spin_lock_zlock(zlock *lock)
+{
+       /* check that zlock is not locked */
+       assert("", LOCK_CNT_NIL(spin_locked_zlock));
+       /* check that spinlocks of lower priorities are not held */
+       assert("", LOCK_CNT_NIL(spin_locked_stack));
+
+       spin_lock(&lock->guard);
+
+       LOCK_CNT_INC(spin_locked_zlock);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void spin_unlock_zlock(zlock *lock)
+{
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_zlock));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(spin_locked_zlock);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&lock->guard);
+}
+
+#define lock_is_locked(lock)          ((lock)->nr_readers != 0)
+#define lock_is_rlocked(lock)         ((lock)->nr_readers > 0)
+#define lock_is_wlocked(lock)         ((lock)->nr_readers < 0)
+#define lock_is_wlocked_once(lock)    ((lock)->nr_readers == -1)
+#define lock_can_be_rlocked(lock)     ((lock)->nr_readers >=0)
+#define lock_mode_compatible(lock, mode)                               \
+             (((mode) == ZNODE_WRITE_LOCK && !lock_is_locked(lock)) || \
+              ((mode) == ZNODE_READ_LOCK && lock_can_be_rlocked(lock)))
+
+/* Since we have R/W znode locks we need additional bidirectional `link'
+   objects to implement n<->m relationship between lock owners and lock
+   objects. We call them `lock handles'.
+
+   Locking: see lock.c/"SHORT-TERM LOCKING"
+*/
+struct lock_handle {
+       /* This flag indicates that a signal to yield a lock was passed to
+          lock owner and counted in owner->nr_signalled
+
+          Locking: this is accessed under spin lock on ->node.
+        */
+       int signaled;
+       /* A link to owner of a lock */
+       lock_stack *owner;
+       /* A link to znode locked */
+       znode *node;
+       /* A list of all locks for a process */
+       struct list_head locks_link;
+       /* A list of all owners for a znode */
+       struct list_head owners_link;
+};
+
+typedef struct lock_request {
+       /* A pointer to uninitialized link object */
+       lock_handle *handle;
+       /* A pointer to the object we want to lock */
+       znode *node;
+       /* Lock mode (ZNODE_READ_LOCK or ZNODE_WRITE_LOCK) */
+       znode_lock_mode mode;
+       /* how dispatch_lock_requests() returns lock request result code */
+       int ret_code;
+} lock_request;
+
+/* A lock stack structure for accumulating locks owned by a process */
+struct lock_stack {
+       /* A guard lock protecting a lock stack */
+       spinlock_t sguard;
+       /* number of znodes which were requested by high priority processes */
+       atomic_t nr_signaled;
+       /* Current priority of a process
+
+          This is only accessed by the current thread and thus requires no
+          locking.
+        */
+       int curpri;
+       /* A list of all locks owned by this process. Elements can be added to
+        * this list only by the current thread. ->node pointers in this list
+        * can be only changed by the current thread. */
+       struct list_head locks;
+       /* When lock_stack waits for the lock, it puts itself on double-linked
+          requestors list of that lock */
+       struct list_head requestors_link;
+       /* Current lock request info.
+
+          This is only accessed by the current thread and thus requires no
+          locking.
+        */
+       lock_request request;
+       /* the following two fields are the lock stack's
+        * synchronization object to use with the standard linux/wait.h
+        * interface. See reiser4_go_to_sleep and __reiser4_wake_up for
+        * usage details. */
+       wait_queue_head_t wait;
+       atomic_t wakeup;
+#if REISER4_DEBUG
+       int nr_locks;           /* number of lock handles in the above list */
+#endif
+};
+
+/*
+  User-visible znode locking functions
+*/
+
+extern int longterm_lock_znode(lock_handle * handle,
+                              znode * node,
+                              znode_lock_mode mode,
+                              znode_lock_request request);
+
+extern void longterm_unlock_znode(lock_handle * handle);
+
+extern int reiser4_check_deadlock(void);
+
+extern lock_stack *get_current_lock_stack(void);
+
+extern void init_lock_stack(lock_stack * owner);
+extern void reiser4_init_lock(zlock * lock);
+
+static inline void init_lh(lock_handle *lh)
+{
+#if REISER4_DEBUG
+       memset(lh, 0, sizeof *lh);
+       INIT_LIST_HEAD(&lh->locks_link);
+       INIT_LIST_HEAD(&lh->owners_link);
+#else
+       lh->node = NULL;
+#endif
+}
+
+static inline  void done_lh(lock_handle *lh)
+{
+       assert("zam-342", lh != NULL);
+       if (lh->node != NULL)
+               longterm_unlock_znode(lh);
+}
+
+extern void move_lh(lock_handle * new, lock_handle * old);
+extern void copy_lh(lock_handle * new, lock_handle * old);
+
+extern int reiser4_prepare_to_sleep(lock_stack * owner);
+extern void reiser4_go_to_sleep(lock_stack * owner);
+extern void __reiser4_wake_up(lock_stack * owner);
+
+extern int lock_stack_isclean(lock_stack * owner);
+
+/* zlock object state check macros: only used in assertions.  Both forms imply that the
+   lock is held by the current thread. */
+extern int znode_is_write_locked(const znode *);
+extern void reiser4_invalidate_lock(lock_handle *);
+
+/* lock ordering is: first take zlock spin lock, then lock stack spin lock */
+#define spin_ordering_pred_stack(stack)                        \
+       (LOCK_CNT_NIL(spin_locked_stack) &&             \
+        LOCK_CNT_NIL(spin_locked_txnmgr) &&            \
+        LOCK_CNT_NIL(spin_locked_inode) &&             \
+        LOCK_CNT_NIL(rw_locked_cbk_cache) &&           \
+        LOCK_CNT_NIL(spin_locked_super_eflush) )
+
+static inline void spin_lock_stack(lock_stack *stack)
+{
+       assert("", spin_ordering_pred_stack(stack));
+       spin_lock(&(stack->sguard));
+       LOCK_CNT_INC(spin_locked_stack);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void spin_unlock_stack(lock_stack *stack)
+{
+       assert_spin_locked(&(stack->sguard));
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_stack));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+       LOCK_CNT_DEC(spin_locked_stack);
+       LOCK_CNT_DEC(spin_locked);
+       spin_unlock(&(stack->sguard));
+}
+
+static inline void reiser4_wake_up(lock_stack * owner)
+{
+       spin_lock_stack(owner);
+       __reiser4_wake_up(owner);
+       spin_unlock_stack(owner);
+}
+
+const char *lock_mode_name(znode_lock_mode lock);
+
+#if REISER4_DEBUG
+extern void check_lock_data(void);
+extern void check_lock_node_data(znode * node);
+#else
+#define check_lock_data() noop
+#define check_lock_node_data() noop
+#endif
+
+/* __LOCK_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/Makefile linux-2.6.20/fs/reiser4/Makefile
--- linux-2.6.20.orig/fs/reiser4/Makefile       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/Makefile    2007-05-06 14:50:43.742989473 +0400
@@ -0,0 +1,99 @@
+#
+# reiser4/Makefile
+#
+
+obj-$(CONFIG_REISER4_FS) += reiser4.o
+
+reiser4-y := \
+                  debug.o \
+                  jnode.o \
+                  znode.o \
+                  key.o \
+                  pool.o \
+                  tree_mod.o \
+                  estimate.o \
+                  carry.o \
+                  carry_ops.o \
+                  lock.o \
+                  tree.o \
+                  context.o \
+                  tap.o \
+                  coord.o \
+                  block_alloc.o \
+                  txnmgr.o \
+                  kassign.o \
+                  flush.o \
+                  wander.o \
+                  eottl.o \
+                  search.o \
+                  page_cache.o \
+                  seal.o \
+                  dscale.o \
+                  flush_queue.o \
+                  ktxnmgrd.o \
+                  blocknrset.o \
+                  super.o \
+                  super_ops.o \
+                  fsdata.o \
+                  export_ops.o \
+                  oid.o \
+                  tree_walk.o \
+                  inode.o \
+                  vfs_ops.o \
+                  as_ops.o \
+                  entd.o\
+                  readahead.o \
+                  status_flags.o \
+                  init_super.o \
+                  safe_link.o \
+           \
+                  plugin/plugin.o \
+                  plugin/plugin_set.o \
+                  plugin/node/node.o \
+                  plugin/object.o \
+                  plugin/cluster.o \
+                  plugin/inode_ops.o \
+                  plugin/inode_ops_rename.o \
+                  plugin/file_ops.o \
+                  plugin/file_ops_readdir.o \
+                  plugin/file_plugin_common.o \
+                  plugin/file/file.o \
+                  plugin/file/tail_conversion.o \
+                  plugin/file/file_conversion.o \
+                  plugin/file/symlink.o \
+                  plugin/file/cryptcompress.o \
+                  plugin/dir_plugin_common.o \
+                  plugin/dir/hashed_dir.o \
+                  plugin/dir/seekable_dir.o \
+                  plugin/node/node40.o \
+           \
+                  plugin/crypto/cipher.o \
+                  plugin/crypto/digest.o \
+           \
+                  plugin/compress/minilzo.o \
+                  plugin/compress/compress.o \
+                  plugin/compress/compress_mode.o \
+           \
+                  plugin/item/static_stat.o \
+                  plugin/item/sde.o \
+                  plugin/item/cde.o \
+                  plugin/item/blackbox.o \
+                  plugin/item/internal.o \
+                  plugin/item/tail.o \
+                  plugin/item/ctail.o \
+                  plugin/item/extent.o \
+                  plugin/item/extent_item_ops.o \
+                  plugin/item/extent_file_ops.o \
+                  plugin/item/extent_flush_ops.o \
+           \
+                  plugin/hash.o \
+                  plugin/fibration.o \
+                  plugin/tail_policy.o \
+                  plugin/item/item.o \
+           \
+                  plugin/security/perm.o \
+                  plugin/space/bitmap.o \
+           \
+                  plugin/disk_format/disk_format40.o \
+                  plugin/disk_format/disk_format.o
+
diff -urN linux-2.6.20.orig/fs/reiser4/oid.c linux-2.6.20/fs/reiser4/oid.c
--- linux-2.6.20.orig/fs/reiser4/oid.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/oid.c       2007-05-06 14:50:43.742989473 +0400
@@ -0,0 +1,141 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "debug.h"
+#include "super.h"
+#include "txnmgr.h"
+
+/* we used to have oid allocation plugin. It was removed because it
+   was recognized as providing unneeded level of abstraction. If one
+   ever will find it useful - look at yet_unneeded_abstractions/oid
+*/
+
+/*
+ * initialize in-memory data for oid allocator at @super. @nr_files and @next
+ * are provided by disk format plugin that reads them from the disk during
+ * mount.
+ */
+int oid_init_allocator(struct super_block *super, oid_t nr_files, oid_t next)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = get_super_private(super);
+
+       sbinfo->next_to_use = next;
+       sbinfo->oids_in_use = nr_files;
+       return 0;
+}
+
+/*
+ * allocate oid and return it. ABSOLUTE_MAX_OID is returned when allocator
+ * runs out of oids.
+ */
+oid_t oid_allocate(struct super_block * super)
+{
+       reiser4_super_info_data *sbinfo;
+       oid_t oid;
+
+       sbinfo = get_super_private(super);
+
+       spin_lock_reiser4_super(sbinfo);
+       if (sbinfo->next_to_use != ABSOLUTE_MAX_OID) {
+               oid = sbinfo->next_to_use++;
+               sbinfo->oids_in_use++;
+       } else
+               oid = ABSOLUTE_MAX_OID;
+       spin_unlock_reiser4_super(sbinfo);
+       return oid;
+}
+
+/*
+ * Tell oid allocator that @oid is now free.
+ */
+int oid_release(struct super_block *super, oid_t oid UNUSED_ARG)
+{
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = get_super_private(super);
+
+       spin_lock_reiser4_super(sbinfo);
+       sbinfo->oids_in_use--;
+       spin_unlock_reiser4_super(sbinfo);
+       return 0;
+}
+
+/*
+ * return next @oid that would be allocated (i.e., returned by oid_allocate())
+ * without actually allocating it. This is used by disk format plugin to save
+ * oid allocator state on the disk.
+ */
+oid_t oid_next(const struct super_block * super)
+{
+       reiser4_super_info_data *sbinfo;
+       oid_t oid;
+
+       sbinfo = get_super_private(super);
+
+       spin_lock_reiser4_super(sbinfo);
+       oid = sbinfo->next_to_use;
+       spin_unlock_reiser4_super(sbinfo);
+       return oid;
+}
+
+/*
+ * returns number of currently used oids. This is used by statfs(2) to report
+ * number of "inodes" and by disk format plugin to save oid allocator state on
+ * the disk.
+ */
+long oids_used(const struct super_block *super)
+{
+       reiser4_super_info_data *sbinfo;
+       oid_t used;
+
+       sbinfo = get_super_private(super);
+
+       spin_lock_reiser4_super(sbinfo);
+       used = sbinfo->oids_in_use;
+       spin_unlock_reiser4_super(sbinfo);
+       if (used < (__u64) ((long)~0) >> 1)
+               return (long)used;
+       else
+               return (long)-1;
+}
+
+/*
+ * Count oid as allocated in atom. This is done after call to oid_allocate()
+ * at the point when we are irrevocably committed to creation of the new file
+ * (i.e., when oid allocation cannot be any longer rolled back due to some
+ * error).
+ */
+void oid_count_allocated(void)
+{
+       txn_atom *atom;
+
+       atom = get_current_atom_locked();
+       atom->nr_objects_created++;
+       spin_unlock_atom(atom);
+}
+
+/*
+ * Count oid as free in atom. This is done after call to oid_release() at the
+ * point when we are irrevocably committed to the deletion of the file (i.e.,
+ * when oid release cannot be any longer rolled back due to some error).
+ */
+void oid_count_released(void)
+{
+       txn_atom *atom;
+
+       atom = get_current_atom_locked();
+       atom->nr_objects_deleted++;
+       spin_unlock_atom(atom);
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/page_cache.c linux-2.6.20/fs/reiser4/page_cache.c
--- linux-2.6.20.orig/fs/reiser4/page_cache.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/page_cache.c        2007-05-06 14:50:43.742989473 +0400
@@ -0,0 +1,736 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Memory pressure hooks. Fake inodes handling. */
+
+/*   GLOSSARY
+
+   . Formatted and unformatted nodes.
+     Elements of reiser4 balanced tree to store data and metadata.
+     Unformatted nodes are pointed to by extent pointers. Such nodes
+     are used to store data of large objects. Unlike unformatted nodes,
+     formatted ones have associated format described by node4X plugin.
+
+   . Jnode (or journal node)
+     The in-memory header which is used to track formatted and unformatted
+     nodes, bitmap nodes, etc. In particular, jnodes are used to track
+     transactional information associated with each block(see reiser4/jnode.c
+     for details).
+
+   . Znode
+     The in-memory header which is used to track formatted nodes. Contains
+     embedded jnode (see reiser4/znode.c for details).
+*/
+
+/* We store all file system meta data (and data, of course) in the page cache.
+
+   What does this mean? In stead of using bread/brelse we create special
+   "fake" inode (one per super block) and store content of formatted nodes
+   into pages bound to this inode in the page cache. In newer kernels bread()
+   already uses inode attached to block device (bd_inode). Advantage of having
+   our own fake inode is that we can install appropriate methods in its
+   address_space operations. Such methods are called by VM on memory pressure
+   (or during background page flushing) and we can use them to react
+   appropriately.
+
+   In initial version we only support one block per page. Support for multiple
+   blocks per page is complicated by relocation.
+
+   To each page, used by reiser4, jnode is attached. jnode is analogous to
+   buffer head. Difference is that jnode is bound to the page permanently:
+   jnode cannot be removed from memory until its backing page is.
+
+   jnode contain pointer to page (->pg field) and page contain pointer to
+   jnode in ->private field. Pointer from jnode to page is protected to by
+   jnode's spinlock and pointer from page to jnode is protected by page lock
+   (PG_locked bit). Lock ordering is: first take page lock, then jnode spin
+   lock. To go into reverse direction use jnode_lock_page() function that uses
+   standard try-lock-and-release device.
+
+   Properties:
+
+   1. when jnode-to-page mapping is established (by jnode_attach_page()), page
+   reference counter is increased.
+
+   2. when jnode-to-page mapping is destroyed (by page_clear_jnode(), page
+   reference counter is decreased.
+
+   3. on jload() reference counter on jnode page is increased, page is
+   kmapped and `referenced'.
+
+   4. on jrelse() inverse operations are performed.
+
+   5. kmapping/kunmapping of unformatted pages is done by read/write methods.
+
+   DEADLOCKS RELATED TO MEMORY PRESSURE. [OUTDATED. Only interesting
+   historically.]
+
+   [In the following discussion, `lock' invariably means long term lock on
+   znode.] (What about page locks?)
+
+   There is some special class of deadlock possibilities related to memory
+   pressure. Locks acquired by other reiser4 threads are accounted for in
+   deadlock prevention mechanism (lock.c), but when ->vm_writeback() is
+   invoked additional hidden arc is added to the locking graph: thread that
+   tries to allocate memory waits for ->vm_writeback() to finish. If this
+   thread keeps lock and ->vm_writeback() tries to acquire this lock, deadlock
+   prevention is useless.
+
+   Another related problem is possibility for ->vm_writeback() to run out of
+   memory itself. This is not a problem for ext2 and friends, because their
+   ->vm_writeback() don't allocate much memory, but reiser4 flush is
+   definitely able to allocate huge amounts of memory.
+
+   It seems that there is no reliable way to cope with the problems above. In
+   stead it was decided that ->vm_writeback() (as invoked in the kswapd
+   context) wouldn't perform any flushing itself, but rather should just wake
+   up some auxiliary thread dedicated for this purpose (or, the same thread
+   that does periodic commit of old atoms (ktxnmgrd.c)).
+
+   Details:
+
+   1. Page is called `reclaimable' against particular reiser4 mount F if this
+   page can be ultimately released by try_to_free_pages() under presumptions
+   that:
+
+    a. ->vm_writeback() for F is no-op, and
+
+    b. none of the threads accessing F are making any progress, and
+
+    c. other reiser4 mounts obey the same memory reservation protocol as F
+    (described below).
+
+   For example, clean un-pinned page, or page occupied by ext2 data are
+   reclaimable against any reiser4 mount.
+
+   When there is more than one reiser4 mount in a system, condition (c) makes
+   reclaim-ability not easily verifiable beyond trivial cases mentioned above.
+
+   THIS COMMENT IS VALID FOR "MANY BLOCKS ON PAGE" CASE
+
+   Fake inode is used to bound formatted nodes and each node is indexed within
+   fake inode by its block number. If block size of smaller than page size, it
+   may so happen that block mapped to the page with formatted node is occupied
+   by unformatted node or is unallocated. This lead to some complications,
+   because flushing whole page can lead to an incorrect overwrite of
+   unformatted node that is moreover, can be cached in some other place as
+   part of the file body. To avoid this, buffers for unformatted nodes are
+   never marked dirty. Also pages in the fake are never marked dirty. This
+   rules out usage of ->writepage() as memory pressure hook. In stead
+   ->releasepage() is used.
+
+   Josh is concerned that page->buffer is going to die. This should not pose
+   significant problem though, because we need to add some data structures to
+   the page anyway (jnode) and all necessary book keeping can be put there.
+
+*/
+
+/* Life cycle of pages/nodes.
+
+   jnode contains reference to page and page contains reference back to
+   jnode. This reference is counted in page ->count. Thus, page bound to jnode
+   cannot be released back into free pool.
+
+    1. Formatted nodes.
+
+      1. formatted node is represented by znode. When new znode is created its
+      ->pg pointer is NULL initially.
+
+      2. when node content is loaded into znode (by call to zload()) for the
+      first time following happens (in call to ->read_node() or
+      ->allocate_node()):
+
+        1. new page is added to the page cache.
+
+        2. this page is attached to znode and its ->count is increased.
+
+        3. page is kmapped.
+
+      3. if more calls to zload() follow (without corresponding zrelses), page
+      counter is left intact and in its stead ->d_count is increased in znode.
+
+      4. each call to zrelse decreases ->d_count. When ->d_count drops to zero
+      ->release_node() is called and page is kunmapped as result.
+
+      5. at some moment node can be captured by a transaction. Its ->x_count
+      is then increased by transaction manager.
+
+      6. if node is removed from the tree (empty node with JNODE_HEARD_BANSHEE
+      bit set) following will happen (also see comment at the top of znode.c):
+
+        1. when last lock is released, node will be uncaptured from
+        transaction. This released reference that transaction manager acquired
+        at the step 5.
+
+        2. when last reference is released, zput() detects that node is
+        actually deleted and calls ->delete_node()
+        operation. page_cache_delete_node() implementation detaches jnode from
+        page and releases page.
+
+      7. otherwise (node wasn't removed from the tree), last reference to
+      znode will be released after transaction manager committed transaction
+      node was in. This implies squallocing of this node (see
+      flush.c). Nothing special happens at this point. Znode is still in the
+      hash table and page is still attached to it.
+
+      8. znode is actually removed from the memory because of the memory
+      pressure, or during umount (znodes_tree_done()). Anyway, znode is
+      removed by the call to zdrop(). At this moment, page is detached from
+      znode and removed from the inode address space.
+
+*/
+
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "super.h"
+#include "entd.h"
+#include "page_cache.h"
+#include "ktxnmgrd.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/mm.h>          /* for struct page */
+#include <linux/swap.h>                /* for struct page */
+#include <linux/pagemap.h>
+#include <linux/bio.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+
+static struct bio *page_bio(struct page *, jnode *, int rw, gfp_t gfp);
+
+static struct address_space_operations formatted_fake_as_ops;
+
+static const oid_t fake_ino = 0x1;
+static const oid_t bitmap_ino = 0x2;
+static const oid_t cc_ino = 0x3;
+
+static void
+init_fake_inode(struct super_block *super, struct inode *fake,
+               struct inode **pfake)
+{
+       assert("nikita-2168", fake->i_state & I_NEW);
+       fake->i_mapping->a_ops = &formatted_fake_as_ops;
+       *pfake = fake;
+       /* NOTE-NIKITA something else? */
+       unlock_new_inode(fake);
+}
+
+/**
+ * reiser4_init_formatted_fake - iget inodes for formatted nodes and bitmaps
+ * @super: super block to init fake inode for
+ *
+ * Initializes fake inode to which formatted nodes are bound in the page cache
+ * and inode for bitmaps.
+ */
+int reiser4_init_formatted_fake(struct super_block *super)
+{
+       struct inode *fake;
+       struct inode *bitmap;
+       struct inode *cc;
+       reiser4_super_info_data *sinfo;
+
+       assert("nikita-1703", super != NULL);
+
+       sinfo = get_super_private_nocheck(super);
+       fake = iget_locked(super, oid_to_ino(fake_ino));
+
+       if (fake != NULL) {
+               init_fake_inode(super, fake, &sinfo->fake);
+
+               bitmap = iget_locked(super, oid_to_ino(bitmap_ino));
+               if (bitmap != NULL) {
+                       init_fake_inode(super, bitmap, &sinfo->bitmap);
+
+                       cc = iget_locked(super, oid_to_ino(cc_ino));
+                       if (cc != NULL) {
+                               init_fake_inode(super, cc, &sinfo->cc);
+                               return 0;
+                       } else {
+                               iput(sinfo->fake);
+                               iput(sinfo->bitmap);
+                               sinfo->fake = NULL;
+                               sinfo->bitmap = NULL;
+                       }
+               } else {
+                       iput(sinfo->fake);
+                       sinfo->fake = NULL;
+               }
+       }
+       return RETERR(-ENOMEM);
+}
+
+/**
+ * reiser4_done_formatted_fake - release inode used by formatted nodes and bitmaps
+ * @super: super block to init fake inode for
+ *
+ * Releases inodes which were used as address spaces of bitmap and formatted
+ * nodes.
+ */
+void reiser4_done_formatted_fake(struct super_block *super)
+{
+       reiser4_super_info_data *sinfo;
+
+       sinfo = get_super_private_nocheck(super);
+
+       if (sinfo->fake != NULL) {
+               iput(sinfo->fake);
+               sinfo->fake = NULL;
+       }
+
+       if (sinfo->bitmap != NULL) {
+               iput(sinfo->bitmap);
+               sinfo->bitmap = NULL;
+       }
+
+       if (sinfo->cc != NULL) {
+               iput(sinfo->cc);
+               sinfo->cc = NULL;
+       }
+       return;
+}
+
+void reiser4_wait_page_writeback(struct page *page)
+{
+       assert("zam-783", PageLocked(page));
+
+       do {
+               unlock_page(page);
+               wait_on_page_writeback(page);
+               lock_page(page);
+       } while (PageWriteback(page));
+}
+
+/* return tree @page is in */
+reiser4_tree *reiser4_tree_by_page(const struct page *page /* page to query */ )
+{
+       assert("nikita-2461", page != NULL);
+       return &get_super_private(page->mapping->host->i_sb)->tree;
+}
+
+/* completion handler for single page bio-based read.
+
+   mpage_end_io_read() would also do. But it's static.
+
+*/
+static int
+end_bio_single_page_read(struct bio *bio, unsigned int bytes_done UNUSED_ARG,
+                        int err UNUSED_ARG)
+{
+       struct page *page;
+
+       if (bio->bi_size != 0) {
+               warning("nikita-3332", "Truncated single page read: %i",
+                       bio->bi_size);
+               return 1;
+       }
+
+       page = bio->bi_io_vec[0].bv_page;
+
+       if (test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+               SetPageUptodate(page);
+       } else {
+               ClearPageUptodate(page);
+               SetPageError(page);
+       }
+       unlock_page(page);
+       bio_put(bio);
+       return 0;
+}
+
+/* completion handler for single page bio-based write.
+
+   mpage_end_io_write() would also do. But it's static.
+
+*/
+static int
+end_bio_single_page_write(struct bio *bio, unsigned int bytes_done UNUSED_ARG,
+                         int err UNUSED_ARG)
+{
+       struct page *page;
+
+       if (bio->bi_size != 0) {
+               warning("nikita-3333", "Truncated single page write: %i",
+                       bio->bi_size);
+               return 1;
+       }
+
+       page = bio->bi_io_vec[0].bv_page;
+
+       if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
+               SetPageError(page);
+       end_page_writeback(page);
+       bio_put(bio);
+       return 0;
+}
+
+/* ->readpage() method for formatted nodes */
+static int formatted_readpage(struct file *f UNUSED_ARG,
+                             struct page *page /* page to read */ )
+{
+       assert("nikita-2412", PagePrivate(page) && jprivate(page));
+       return reiser4_page_io(page, jprivate(page), READ,
+                              reiser4_ctx_gfp_mask_get());
+}
+
+/**
+ * reiser4_page_io - submit single-page bio request
+ * @page: page to perform io for
+ * @node: jnode of page
+ * @rw: read or write
+ * @gfp: gfp mask for bio allocation
+ *
+ * Submits single page read or write.
+ */
+int reiser4_page_io(struct page *page, jnode *node, int rw, gfp_t gfp)
+{
+       struct bio *bio;
+       int result;
+
+       assert("nikita-2094", page != NULL);
+       assert("nikita-2226", PageLocked(page));
+       assert("nikita-2634", node != NULL);
+       assert("nikita-2893", rw == READ || rw == WRITE);
+
+       if (rw) {
+               if (unlikely(page->mapping->host->i_sb->s_flags & MS_RDONLY)) {
+                       unlock_page(page);
+                       return 0;
+               }
+       }
+
+       bio = page_bio(page, node, rw, gfp);
+       if (!IS_ERR(bio)) {
+               if (rw == WRITE) {
+                       SetPageWriteback(page);
+                       unlock_page(page);
+               }
+               reiser4_submit_bio(rw, bio);
+               result = 0;
+       } else {
+               unlock_page(page);
+               result = PTR_ERR(bio);
+       }
+
+       return result;
+}
+
+/* helper function to construct bio for page */
+static struct bio *page_bio(struct page *page, jnode * node, int rw, gfp_t gfp)
+{
+       struct bio *bio;
+       assert("nikita-2092", page != NULL);
+       assert("nikita-2633", node != NULL);
+
+       /* Simple implementation in the assumption that blocksize == pagesize.
+
+          We only have to submit one block, but submit_bh() will allocate bio
+          anyway, so lets use all the bells-and-whistles of bio code.
+        */
+
+       bio = bio_alloc(gfp, 1);
+       if (bio != NULL) {
+               int blksz;
+               struct super_block *super;
+               reiser4_block_nr blocknr;
+
+               super = page->mapping->host->i_sb;
+               assert("nikita-2029", super != NULL);
+               blksz = super->s_blocksize;
+               assert("nikita-2028", blksz == (int)PAGE_CACHE_SIZE);
+
+               spin_lock_jnode(node);
+               blocknr = *jnode_get_io_block(node);
+               spin_unlock_jnode(node);
+
+               assert("nikita-2275", blocknr != (reiser4_block_nr) 0);
+               assert("nikita-2276", !reiser4_blocknr_is_fake(&blocknr));
+
+               bio->bi_bdev = super->s_bdev;
+               /* fill bio->bi_sector before calling bio_add_page(), because
+                * q->merge_bvec_fn may want to inspect it (see
+                * drivers/md/linear.c:linear_mergeable_bvec() for example. */
+               bio->bi_sector = blocknr * (blksz >> 9);
+
+               if (!bio_add_page(bio, page, blksz, 0)) {
+                       warning("nikita-3452",
+                               "Single page bio cannot be constructed");
+                       return ERR_PTR(RETERR(-EINVAL));
+               }
+
+               /* bio -> bi_idx is filled by bio_init() */
+               bio->bi_end_io = (rw == READ) ?
+                   end_bio_single_page_read : end_bio_single_page_write;
+
+               return bio;
+       } else
+               return ERR_PTR(RETERR(-ENOMEM));
+}
+
+/* this function is internally called by jnode_make_dirty() */
+int reiser4_set_page_dirty_internal(struct page *page)
+{
+       struct address_space *mapping;
+
+       mapping = page->mapping;
+       BUG_ON(mapping == NULL);
+
+       if (!TestSetPageDirty(page)) {
+               if (mapping_cap_account_dirty(mapping))
+                       inc_zone_page_state(page, NR_FILE_DIRTY);
+
+               __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+       }
+
+       /* znode must be dirty ? */
+       if (mapping->host == reiser4_get_super_fake(mapping->host->i_sb))
+               assert("", JF_ISSET(jprivate(page), JNODE_DIRTY));
+       return 0;
+}
+
+#if REISER4_DEBUG
+
+/**
+ * can_hit_entd
+ *
+ * This is used on
+ */
+static int can_hit_entd(reiser4_context *ctx, struct super_block *s)
+{
+       if (ctx == NULL || ((unsigned long)ctx->magic) != context_magic)
+               return 1;
+       if (ctx->super != s)
+               return 1;
+       if (get_super_private(s)->entd.tsk == current)
+               return 0;
+       if (!lock_stack_isclean(&ctx->stack))
+               return 0;
+       if (ctx->trans->atom != NULL)
+               return 0;
+       return 1;
+}
+
+#endif
+
+/**
+ * reiser4_writepage - writepage of struct address_space_operations
+ * @page: page to write
+ * @wbc:
+ *
+ *
+ */
+/* Common memory pressure notification. */
+int reiser4_writepage(struct page *page,
+                     struct writeback_control *wbc)
+{
+       struct super_block *s;
+       reiser4_context *ctx;
+
+       assert("vs-828", PageLocked(page));
+
+       s = page->mapping->host->i_sb;
+       ctx = get_current_context_check();
+
+       assert("", can_hit_entd(ctx, s));
+
+       return write_page_by_ent(page, wbc);
+}
+
+/* ->set_page_dirty() method of formatted address_space */
+static int formatted_set_page_dirty(struct page *page)
+{
+       assert("nikita-2173", page != NULL);
+       BUG();
+       return __set_page_dirty_nobuffers(page);
+}
+
+/* writepages method of address space operations in reiser4 is used to involve
+   into transactions pages which are dirtied via mmap. Only regular files can
+   have such pages. Fake inode is used to access formatted nodes via page
+   cache. As formatted nodes can never be mmaped, fake inode's writepages has
+   nothing to do */
+static int
+writepages_fake(struct address_space *mapping, struct writeback_control *wbc)
+{
+       return 0;
+}
+
+/* address space operations for the fake inode */
+static struct address_space_operations formatted_fake_as_ops = {
+       /* Perform a writeback of a single page as a memory-freeing
+        * operation. */
+       .writepage = reiser4_writepage,
+       /* this is called to read formatted node */
+       .readpage = formatted_readpage,
+       /* ->sync_page() method of fake inode address space operations. Called
+          from wait_on_page() and lock_page().
+
+          This is most annoyingly misnomered method. Actually it is called
+          from wait_on_page_bit() and lock_page() and its purpose is to
+          actually start io by jabbing device drivers.
+        */
+       .sync_page = block_sync_page,
+       /* Write back some dirty pages from this mapping. Called from sync.
+          called during sync (pdflush) */
+       .writepages = writepages_fake,
+       /* Set a page dirty */
+       .set_page_dirty = formatted_set_page_dirty,
+       /* used for read-ahead. Not applicable */
+       .readpages = NULL,
+       .prepare_write = NULL,
+       .commit_write = NULL,
+       .bmap = NULL,
+       /* called just before page is being detached from inode mapping and
+          removed from memory. Called on truncate, cut/squeeze, and
+          umount. */
+       .invalidatepage = reiser4_invalidatepage,
+       /* this is called by shrink_cache() so that file system can try to
+          release objects (jnodes, buffers, journal heads) attached to page
+          and, may be made page itself free-able.
+        */
+       .releasepage = reiser4_releasepage,
+       .direct_IO = NULL
+};
+
+/* called just before page is released (no longer used by reiser4). Callers:
+   jdelete() and extent2tail(). */
+void reiser4_drop_page(struct page *page)
+{
+       assert("nikita-2181", PageLocked(page));
+       clear_page_dirty_for_io(page);
+       ClearPageUptodate(page);
+#if defined(PG_skipped)
+       ClearPageSkipped(page);
+#endif
+       unlock_page(page);
+}
+
+#define JNODE_GANG_SIZE (16)
+
+/* find all jnodes from range specified and invalidate them */
+static int
+truncate_jnodes_range(struct inode *inode, pgoff_t from, pgoff_t count)
+{
+       reiser4_inode *info;
+       int truncated_jnodes;
+       reiser4_tree *tree;
+       unsigned long index;
+       unsigned long end;
+
+       if (inode_file_plugin(inode) ==
+           file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID))
+               /* No need to get rid of jnodes here: if the single jnode of
+                  page cluster did not have page, then it was found and killed
+                  before in
+                  truncate_page_cluster_cryptcompress()->jput()->jput_final(),
+                  otherwise it will be dropped by reiser4_invalidatepage() */
+               return 0;
+       truncated_jnodes = 0;
+
+       info = reiser4_inode_data(inode);
+       tree = reiser4_tree_by_inode(inode);
+
+       index = from;
+       end = from + count;
+
+       while (1) {
+               jnode *gang[JNODE_GANG_SIZE];
+               int taken;
+               int i;
+               jnode *node;
+
+               assert("nikita-3466", index <= end);
+
+               read_lock_tree(tree);
+               taken =
+                   radix_tree_gang_lookup(jnode_tree_by_reiser4_inode(info),
+                                          (void **)gang, index,
+                                          JNODE_GANG_SIZE);
+               for (i = 0; i < taken; ++i) {
+                       node = gang[i];
+                       if (index_jnode(node) < end)
+                               jref(node);
+                       else
+                               gang[i] = NULL;
+               }
+               read_unlock_tree(tree);
+
+               for (i = 0; i < taken; ++i) {
+                       node = gang[i];
+                       if (node != NULL) {
+                               index = max(index, index_jnode(node));
+                               spin_lock_jnode(node);
+                               assert("edward-1457", node->pg == NULL);
+                               /* this is always called after
+                                  truncate_inode_pages_range(). Therefore, here
+                                  jnode can not have page. New pages can not be
+                                  created because truncate_jnodes_range goes
+                                  under exclusive access on file obtained,
+                                  where as new page creation requires
+                                  non-exclusive access obtained */
+                               JF_SET(node, JNODE_HEARD_BANSHEE);
+                               reiser4_uncapture_jnode(node);
+                               unhash_unformatted_jnode(node);
+                               truncated_jnodes++;
+                               jput(node);
+                       } else
+                               break;
+               }
+               if (i != taken || taken == 0)
+                       break;
+       }
+       return truncated_jnodes;
+}
+
+/* Truncating files in reiser4: problems and solutions.
+
+   VFS calls fs's truncate after it has called truncate_inode_pages()
+   to get rid of pages corresponding to part of file being truncated.
+   In reiser4 it may cause existence of unallocated extents which do
+   not have jnodes. Flush code does not expect that. Solution of this
+   problem is straightforward. As vfs's truncate is implemented using
+   setattr operation, it seems reasonable to have ->setattr() that
+   will cut file body. However, flush code also does not expect dirty
+   pages without parent items, so it is impossible to cut all items,
+   then truncate all pages in two steps. We resolve this problem by
+   cutting items one-by-one. Each such fine-grained step performed
+   under longterm znode lock calls at the end ->kill_hook() method of
+   a killed item to remove its binded pages and jnodes.
+
+   The following function is a common part of mentioned kill hooks.
+   Also, this is called before tail-to-extent conversion (to not manage
+   few copies of the data).
+*/
+void reiser4_invalidate_pages(struct address_space *mapping, pgoff_t from,
+                             unsigned long count, int even_cows)
+{
+       loff_t from_bytes, count_bytes;
+
+       if (count == 0)
+               return;
+       from_bytes = ((loff_t) from) << PAGE_CACHE_SHIFT;
+       count_bytes = ((loff_t) count) << PAGE_CACHE_SHIFT;
+
+       unmap_mapping_range(mapping, from_bytes, count_bytes, even_cows);
+       truncate_inode_pages_range(mapping, from_bytes,
+                                  from_bytes + count_bytes - 1);
+       truncate_jnodes_range(mapping->host, from, count);
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/page_cache.h linux-2.6.20/fs/reiser4/page_cache.h
--- linux-2.6.20.orig/fs/reiser4/page_cache.h   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/page_cache.h        2007-05-06 14:50:43.746990723 +0400
@@ -0,0 +1,68 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+/* Memory pressure hooks. Fake inodes handling. See page_cache.c. */
+
+#if !defined( __REISER4_PAGE_CACHE_H__ )
+#define __REISER4_PAGE_CACHE_H__
+
+#include "forward.h"
+#include "context.h"            /* for reiser4_ctx_gfp_mask_get() */
+
+#include <linux/fs.h>          /* for struct super_block, address_space  */
+#include <linux/mm.h>          /* for struct page  */
+#include <linux/pagemap.h>     /* for lock_page()  */
+#include <linux/vmalloc.h>     /* for __vmalloc()  */
+
+extern int reiser4_init_formatted_fake(struct super_block *);
+extern void reiser4_done_formatted_fake(struct super_block *);
+
+extern reiser4_tree *reiser4_tree_by_page(const struct page *);
+
+extern int reiser4_set_page_dirty_internal(struct page *);
+
+#define reiser4_submit_bio(rw, bio) submit_bio((rw), (bio))
+
+extern void reiser4_wait_page_writeback(struct page *);
+static inline void lock_and_wait_page_writeback(struct page *page)
+{
+       lock_page(page);
+       if (unlikely(PageWriteback(page)))
+               reiser4_wait_page_writeback(page);
+}
+
+#define jprivate(page) ((jnode *)page_private(page))
+
+extern int reiser4_page_io(struct page *, jnode *, int rw, gfp_t);
+extern void reiser4_drop_page(struct page *);
+extern void reiser4_invalidate_pages(struct address_space *, pgoff_t from,
+                                    unsigned long count, int even_cows);
+extern void capture_reiser4_inodes(struct super_block *,
+                                  struct writeback_control *);
+static inline void * reiser4_vmalloc (unsigned long size)
+{
+       return __vmalloc(size,
+                        reiser4_ctx_gfp_mask_get() | __GFP_HIGHMEM,
+                        PAGE_KERNEL);
+}
+
+#define PAGECACHE_TAG_REISER4_MOVED PAGECACHE_TAG_DIRTY
+
+#if REISER4_DEBUG
+extern void print_page(const char *prefix, struct page *page);
+#else
+#define print_page(prf, p) noop
+#endif
+
+/* __REISER4_PAGE_CACHE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/cluster.c linux-2.6.20/fs/reiser4/plugin/cluster.c
--- linux-2.6.20.orig/fs/reiser4/plugin/cluster.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/cluster.c    2007-05-06 14:50:43.746990723 +0400
@@ -0,0 +1,71 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Contains reiser4 cluster plugins (see
+   http://www.namesys.com/cryptcompress_design.html
+   "Concepts of clustering" for details). */
+
+#include "plugin_header.h"
+#include "plugin.h"
+#include "../inode.h"
+
+static int change_cluster(struct inode *inode,
+                         reiser4_plugin * plugin,
+                         pset_member memb)
+{
+       assert("edward-1324", inode != NULL);
+       assert("edward-1325", plugin != NULL);
+       assert("edward-1326", is_reiser4_inode(inode));
+       assert("edward-1327", plugin->h.type_id == REISER4_CLUSTER_PLUGIN_TYPE);
+
+       /* Can't change the cluster plugin for already existent regular files. */
+       if (!plugin_of_group(inode_file_plugin(inode), REISER4_DIRECTORY_FILE))
+               return RETERR(-EINVAL);
+
+       /* If matches, nothing to change. */
+       if (inode_hash_plugin(inode) != NULL &&
+           inode_hash_plugin(inode)->h.id == plugin->h.id)
+               return 0;
+
+       return aset_set_unsafe(&reiser4_inode_data(inode)->pset,
+                              PSET_CLUSTER, plugin);
+}
+
+static reiser4_plugin_ops cluster_plugin_ops = {
+       .init = NULL,
+       .load = NULL,
+       .save_len = NULL,
+       .save = NULL,
+       .change = &change_cluster
+};
+
+#define SUPPORT_CLUSTER(SHIFT, ID, LABEL, DESC)                        \
+       [CLUSTER_ ## ID ## _ID] = {                             \
+               .h = {                                          \
+                       .type_id = REISER4_CLUSTER_PLUGIN_TYPE, \
+                       .id = CLUSTER_ ## ID ## _ID,            \
+                       .pops = &cluster_plugin_ops,            \
+                       .label = LABEL,                         \
+                       .desc = DESC,                           \
+                       .linkage = {NULL, NULL}                 \
+               },                                              \
+               .shift = SHIFT                                  \
+       }
+
+cluster_plugin cluster_plugins[LAST_CLUSTER_ID] = {
+       SUPPORT_CLUSTER(16, 64K, "64K", "Large"),
+       SUPPORT_CLUSTER(15, 32K, "32K", "Big"),
+       SUPPORT_CLUSTER(14, 16K, "16K", "Average"),
+       SUPPORT_CLUSTER(13, 8K, "8K", "Small"),
+       SUPPORT_CLUSTER(12, 4K, "4K", "Minimal")
+};
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 120
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/cluster.h linux-2.6.20/fs/reiser4/plugin/cluster.h
--- linux-2.6.20.orig/fs/reiser4/plugin/cluster.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/cluster.h    2007-05-06 14:50:43.746990723 +0400
@@ -0,0 +1,343 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* This file contains page/cluster index translators and offset modulators
+   See http://www.namesys.com/cryptcompress_design.html for details */
+
+#if !defined( __FS_REISER4_CLUSTER_H__ )
+#define __FS_REISER4_CLUSTER_H__
+
+#include "../inode.h"
+
+static inline int inode_cluster_shift(struct inode *inode)
+{
+       assert("edward-92", inode != NULL);
+       assert("edward-93", reiser4_inode_data(inode) != NULL);
+
+       return inode_cluster_plugin(inode)->shift;
+}
+
+static inline unsigned cluster_nrpages_shift(struct inode *inode)
+{
+       return inode_cluster_shift(inode) - PAGE_CACHE_SHIFT;
+}
+
+/* cluster size in page units */
+static inline unsigned cluster_nrpages(struct inode *inode)
+{
+       return 1U << cluster_nrpages_shift(inode);
+}
+
+static inline size_t inode_cluster_size(struct inode *inode)
+{
+       assert("edward-96", inode != NULL);
+
+       return 1U << inode_cluster_shift(inode);
+}
+
+static inline cloff_t pg_to_clust(pgoff_t idx, struct inode *inode)
+{
+       return idx >> cluster_nrpages_shift(inode);
+}
+
+static inline pgoff_t clust_to_pg(cloff_t idx, struct inode *inode)
+{
+       return idx << cluster_nrpages_shift(inode);
+}
+
+static inline pgoff_t pg_to_clust_to_pg(pgoff_t idx, struct inode *inode)
+{
+       return clust_to_pg(pg_to_clust(idx, inode), inode);
+}
+
+static inline pgoff_t off_to_pg(loff_t off)
+{
+       return (off >> PAGE_CACHE_SHIFT);
+}
+
+static inline loff_t pg_to_off(pgoff_t idx)
+{
+       return ((loff_t) (idx) << PAGE_CACHE_SHIFT);
+}
+
+static inline cloff_t off_to_clust(loff_t off, struct inode *inode)
+{
+       return off >> inode_cluster_shift(inode);
+}
+
+static inline loff_t clust_to_off(cloff_t idx, struct inode *inode)
+{
+       return (loff_t) idx << inode_cluster_shift(inode);
+}
+
+static inline unsigned long count_to_nr(loff_t count, unsigned shift)
+{
+       return (count + (1UL << shift) - 1) >> shift;
+}
+
+/* number of pages occupied by @count bytes */
+static inline pgoff_t count_to_nrpages(loff_t count)
+{
+       return count_to_nr(count, PAGE_CACHE_SHIFT);
+}
+
+/* number of clusters occupied by @count bytes */
+static inline cloff_t count_to_nrclust(loff_t count, struct inode *inode)
+{
+       return count_to_nr(count, inode_cluster_shift(inode));
+}
+
+/* number of clusters occupied by @count pages */
+static inline cloff_t pgcount_to_nrclust(pgoff_t count, struct inode *inode)
+{
+       return count_to_nr(count, cluster_nrpages_shift(inode));
+}
+
+static inline loff_t off_to_clust_to_off(loff_t off, struct inode *inode)
+{
+       return clust_to_off(off_to_clust(off, inode), inode);
+}
+
+static inline pgoff_t off_to_clust_to_pg(loff_t off, struct inode *inode)
+{
+       return clust_to_pg(off_to_clust(off, inode), inode);
+}
+
+static inline unsigned off_to_pgoff(loff_t off)
+{
+       return off & (PAGE_CACHE_SIZE - 1);
+}
+
+static inline unsigned off_to_cloff(loff_t off, struct inode *inode)
+{
+       return off & ((loff_t) (inode_cluster_size(inode)) - 1);
+}
+
+static inline unsigned
+pg_to_off_to_cloff(unsigned long idx, struct inode *inode)
+{
+       return off_to_cloff(pg_to_off(idx), inode);
+}
+
+/* if @size != 0, returns index of the page
+   which contains the last byte of the file */
+static inline pgoff_t size_to_pg(loff_t size)
+{
+       return (size ? off_to_pg(size - 1) : 0);
+}
+
+/* minimal index of the page which doesn't contain
+   file data */
+static inline pgoff_t size_to_next_pg(loff_t size)
+{
+       return (size ? off_to_pg(size - 1) + 1 : 0);
+}
+
+/* how many bytes of file of size @cnt can be contained
+   in page of index @idx */
+static inline unsigned cnt_to_pgcnt(loff_t cnt, pgoff_t idx)
+{
+       if (idx > off_to_pg(cnt))
+               return 0;
+       if (idx < off_to_pg(cnt))
+               return PAGE_CACHE_SIZE;
+       return off_to_pgoff(cnt);
+}
+
+/* how many bytes of file of size @cnt can be contained
+   in logical cluster of index @idx */
+static inline unsigned cnt_to_clcnt(loff_t cnt, cloff_t idx,
+                                   struct inode *inode)
+{
+       if (idx > off_to_clust(cnt, inode))
+               return 0;
+       if (idx < off_to_clust(cnt, inode))
+               return inode_cluster_size(inode);
+       return off_to_cloff(cnt, inode);
+}
+
+static inline unsigned
+fsize_to_count(reiser4_cluster_t * clust, struct inode *inode)
+{
+       assert("edward-288", clust != NULL);
+       assert("edward-289", inode != NULL);
+
+       return cnt_to_clcnt(inode->i_size, clust->index, inode);
+}
+
+static inline int
+cluster_is_complete(reiser4_cluster_t * clust, struct inode * inode)
+{
+       return clust->tc.lsize == inode_cluster_size(inode);
+}
+
+static inline void reiser4_slide_init(reiser4_slide_t * win)
+{
+       assert("edward-1084", win != NULL);
+       memset(win, 0, sizeof *win);
+}
+
+static inline tfm_action
+cluster_get_tfm_act(tfm_cluster_t * tc)
+{
+       assert("edward-1356", tc != NULL);
+       return tc->act;
+}
+
+static inline void
+cluster_set_tfm_act(tfm_cluster_t * tc, tfm_action act)
+{
+       assert("edward-1356", tc != NULL);
+       tc->act = act;
+}
+
+static inline void
+cluster_init_act (reiser4_cluster_t * clust, tfm_action act, reiser4_slide_t * window){
+       assert("edward-84", clust != NULL);
+       memset(clust, 0, sizeof *clust);
+       cluster_set_tfm_act(&clust->tc, act);
+       clust->dstat = INVAL_DISK_CLUSTER;
+       clust->win = window;
+}
+
+static inline void
+cluster_init_read(reiser4_cluster_t * clust, reiser4_slide_t * window)
+{
+       cluster_init_act (clust, TFMA_READ, window);
+}
+
+static inline void
+cluster_init_write(reiser4_cluster_t * clust, reiser4_slide_t * window)
+{
+       cluster_init_act (clust, TFMA_WRITE, window);
+}
+
+static inline int dclust_get_extension_dsize(hint_t * hint)
+{
+       return hint->ext_coord.extension.ctail.dsize;
+}
+
+static inline void dclust_set_extension_dsize(hint_t * hint, int dsize)
+{
+       hint->ext_coord.extension.ctail.dsize = dsize;
+}
+
+static inline int dclust_get_extension_shift(hint_t * hint)
+{
+       return hint->ext_coord.extension.ctail.shift;
+}
+
+static inline int dclust_get_extension_ncount(hint_t * hint)
+{
+       return hint->ext_coord.extension.ctail.ncount;
+}
+
+static inline void dclust_inc_extension_ncount(hint_t * hint)
+{
+       hint->ext_coord.extension.ctail.ncount ++;
+}
+
+static inline void dclust_init_extension(hint_t * hint)
+{
+       memset(&hint->ext_coord.extension.ctail, 0,
+              sizeof(hint->ext_coord.extension.ctail));
+}
+
+static inline int hint_is_unprepped_dclust(hint_t * hint)
+{
+       assert("edward-1451", hint_is_valid(hint));
+       return dclust_get_extension_shift(hint) == (int)UCTAIL_SHIFT;
+}
+
+static inline void coord_set_between_clusters(coord_t * coord)
+{
+#if REISER4_DEBUG
+       int result;
+       result = zload(coord->node);
+       assert("edward-1296", !result);
+#endif
+       if (!coord_is_between_items(coord)) {
+               coord->between = AFTER_ITEM;
+               coord->unit_pos = 0;
+       }
+#if REISER4_DEBUG
+       zrelse(coord->node);
+#endif
+}
+
+int reiser4_inflate_cluster(reiser4_cluster_t *, struct inode *);
+int find_disk_cluster(reiser4_cluster_t *, struct inode *, int read,
+                     znode_lock_mode mode);
+int flush_cluster_pages(reiser4_cluster_t *, jnode *, struct inode *);
+int reiser4_deflate_cluster(reiser4_cluster_t *, struct inode *);
+void truncate_page_cluster_cryptcompress(struct inode *inode, cloff_t start,
+                                        int even_cows);
+void invalidate_hint_cluster(reiser4_cluster_t * clust);
+void put_hint_cluster(reiser4_cluster_t * clust, struct inode *inode,
+                     znode_lock_mode mode);
+int get_disk_cluster_locked(reiser4_cluster_t * clust, struct inode *inode,
+                           znode_lock_mode lock_mode);
+void reset_cluster_params(reiser4_cluster_t * clust);
+int set_cluster_by_page(reiser4_cluster_t * clust, struct page * page,
+                       int count);
+int prepare_page_cluster(struct inode *inode, reiser4_cluster_t * clust,
+                        int capture);
+void reiser4_release_cluster_pages(reiser4_cluster_t *);
+void put_cluster_handle(reiser4_cluster_t * clust);
+int grab_tfm_stream(struct inode *inode, tfm_cluster_t * tc, tfm_stream_id id);
+int tfm_cluster_is_uptodate(tfm_cluster_t * tc);
+void tfm_cluster_set_uptodate(tfm_cluster_t * tc);
+void tfm_cluster_clr_uptodate(tfm_cluster_t * tc);
+
+/* move cluster handle to the target position
+   specified by the page of index @pgidx
+*/
+static inline void move_cluster_forward(reiser4_cluster_t * clust,
+                                       struct inode *inode,
+                                       pgoff_t pgidx)
+{
+       assert("edward-1297", clust != NULL);
+       assert("edward-1298", inode != NULL);
+
+       reset_cluster_params(clust);
+       if (clust->index_valid &&
+           /* Hole in the indices. Hint became invalid and can not be
+              used by find_cluster_item() even if seal/node versions
+              will coincide */
+           pg_to_clust(pgidx, inode) != clust->index + 1) {
+               reiser4_unset_hint(clust->hint);
+               invalidate_hint_cluster(clust);
+       }
+       clust->index = pg_to_clust(pgidx, inode);
+       clust->index_valid = 1;
+}
+
+static inline int
+alloc_clust_pages(reiser4_cluster_t * clust, struct inode *inode)
+{
+       assert("edward-791", clust != NULL);
+       assert("edward-792", inode != NULL);
+       clust->pages =
+               kmalloc(sizeof(*clust->pages) << inode_cluster_shift(inode),
+                       reiser4_ctx_gfp_mask_get());
+       if (!clust->pages)
+               return -ENOMEM;
+       return 0;
+}
+
+static inline void free_clust_pages(reiser4_cluster_t * clust)
+{
+       kfree(clust->pages);
+}
+
+#endif                         /* __FS_REISER4_CLUSTER_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/compress.c linux-2.6.20/fs/reiser4/plugin/compress/compress.c
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/compress.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/compress.c  2007-05-06 14:50:43.746990723 +0400
@@ -0,0 +1,381 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* reiser4 compression transform plugins */
+
+#include "../../debug.h"
+#include "../../inode.h"
+#include "../plugin.h"
+#include "minilzo.h"
+
+#include <linux/zlib.h>
+#include <linux/types.h>
+#include <linux/hardirq.h>
+
+static int change_compression(struct inode *inode,
+                             reiser4_plugin * plugin,
+                             pset_member memb)
+{
+       assert("edward-1316", inode != NULL);
+       assert("edward-1317", plugin != NULL);
+       assert("edward-1318", is_reiser4_inode(inode));
+       assert("edward-1319",
+              plugin->h.type_id == REISER4_COMPRESSION_PLUGIN_TYPE);
+
+       /* cannot change compression plugin of already existing regular object */
+       if (!plugin_of_group(inode_file_plugin(inode), REISER4_DIRECTORY_FILE))
+               return RETERR(-EINVAL);
+
+       /* If matches, nothing to change. */
+       if (inode_hash_plugin(inode) != NULL &&
+           inode_hash_plugin(inode)->h.id == plugin->h.id)
+               return 0;
+
+       return aset_set_unsafe(&reiser4_inode_data(inode)->pset,
+                              PSET_COMPRESSION, plugin);
+}
+
+static reiser4_plugin_ops compression_plugin_ops = {
+       .init = NULL,
+       .load = NULL,
+       .save_len = NULL,
+       .save = NULL,
+       .change = &change_compression
+};
+
+/******************************************************************************/
+/*                         gzip1 compression                                  */
+/******************************************************************************/
+
+#define GZIP1_DEF_LEVEL                        Z_BEST_SPEED
+#define GZIP1_DEF_WINBITS              15
+#define GZIP1_DEF_MEMLEVEL             MAX_MEM_LEVEL
+
+static int gzip1_init(void)
+{
+       int ret = -EINVAL;
+#if REISER4_ZLIB
+       ret = 0;
+#endif
+       if (ret == -EINVAL)
+               warning("edward-1337", "Zlib not compiled into kernel");
+       return ret;
+}
+
+static int gzip1_overrun(unsigned src_len UNUSED_ARG)
+{
+       return 0;
+}
+
+static coa_t gzip1_alloc(tfm_action act)
+{
+       coa_t coa = NULL;
+#if REISER4_ZLIB
+       int ret = 0;
+       switch (act) {
+       case TFMA_WRITE:        /* compress */
+               coa = reiser4_vmalloc(zlib_deflate_workspacesize());
+               if (!coa) {
+                       ret = -ENOMEM;
+                       break;
+               }
+               memset(coa, 0, zlib_deflate_workspacesize());
+               break;
+       case TFMA_READ: /* decompress */
+               coa = reiser4_vmalloc(zlib_inflate_workspacesize());
+               if (!coa) {
+                       ret = -ENOMEM;
+                       break;
+               }
+               memset(coa, 0, zlib_inflate_workspacesize());
+               break;
+       default:
+               impossible("edward-767",
+                          "trying to alloc workspace for unknown tfm action");
+       }
+       if (ret) {
+               warning("edward-768",
+                       "alloc workspace for gzip1 (tfm action = %d) failed\n",
+                       act);
+               return ERR_PTR(ret);
+       }
+#endif
+       return coa;
+}
+
+static void gzip1_free(coa_t coa, tfm_action act)
+{
+       assert("edward-769", coa != NULL);
+
+       switch (act) {
+       case TFMA_WRITE:        /* compress */
+               vfree(coa);
+               break;
+       case TFMA_READ:         /* decompress */
+               vfree(coa);
+               break;
+       default:
+               impossible("edward-770", "unknown tfm action");
+       }
+       return;
+}
+
+static int gzip1_min_size_deflate(void)
+{
+       return 64;
+}
+
+static void
+gzip1_compress(coa_t coa, __u8 * src_first, unsigned src_len,
+              __u8 * dst_first, unsigned *dst_len)
+{
+#if REISER4_ZLIB
+       int ret = 0;
+       struct z_stream_s stream;
+
+       memset(&stream, 0, sizeof(stream));
+
+       assert("edward-842", coa != NULL);
+       assert("edward-875", src_len != 0);
+
+       stream.workspace = coa;
+       ret = zlib_deflateInit2(&stream, GZIP1_DEF_LEVEL, Z_DEFLATED,
+                               -GZIP1_DEF_WINBITS, GZIP1_DEF_MEMLEVEL,
+                               Z_DEFAULT_STRATEGY);
+       if (ret != Z_OK) {
+               warning("edward-771", "zlib_deflateInit2 returned %d\n", ret);
+               goto rollback;
+       }
+       ret = zlib_deflateReset(&stream);
+       if (ret != Z_OK) {
+               warning("edward-772", "zlib_deflateReset returned %d\n", ret);
+               goto rollback;
+       }
+       stream.next_in = src_first;
+       stream.avail_in = src_len;
+       stream.next_out = dst_first;
+       stream.avail_out = *dst_len;
+
+       ret = zlib_deflate(&stream, Z_FINISH);
+       if (ret != Z_STREAM_END) {
+               if (ret != Z_OK)
+                       warning("edward-773",
+                               "zlib_deflate returned %d\n", ret);
+               goto rollback;
+       }
+       *dst_len = stream.total_out;
+       return;
+      rollback:
+       *dst_len = src_len;
+#endif
+       return;
+}
+
+static void
+gzip1_decompress(coa_t coa, __u8 * src_first, unsigned src_len,
+                __u8 * dst_first, unsigned *dst_len)
+{
+#if REISER4_ZLIB
+       int ret = 0;
+       struct z_stream_s stream;
+
+       memset(&stream, 0, sizeof(stream));
+
+       assert("edward-843", coa != NULL);
+       assert("edward-876", src_len != 0);
+
+       stream.workspace = coa;
+       ret = zlib_inflateInit2(&stream, -GZIP1_DEF_WINBITS);
+       if (ret != Z_OK) {
+               warning("edward-774", "zlib_inflateInit2 returned %d\n", ret);
+               return;
+       }
+       ret = zlib_inflateReset(&stream);
+       if (ret != Z_OK) {
+               warning("edward-775", "zlib_inflateReset returned %d\n", ret);
+               return;
+       }
+
+       stream.next_in = src_first;
+       stream.avail_in = src_len;
+       stream.next_out = dst_first;
+       stream.avail_out = *dst_len;
+
+       ret = zlib_inflate(&stream, Z_SYNC_FLUSH);
+       /*
+        * Work around a bug in zlib, which sometimes wants to taste an extra
+        * byte when being used in the (undocumented) raw deflate mode.
+        * (From USAGI).
+        */
+       if (ret == Z_OK && !stream.avail_in && stream.avail_out) {
+               u8 zerostuff = 0;
+               stream.next_in = &zerostuff;
+               stream.avail_in = 1;
+               ret = zlib_inflate(&stream, Z_FINISH);
+       }
+       if (ret != Z_STREAM_END) {
+               warning("edward-776", "zlib_inflate returned %d\n", ret);
+               return;
+       }
+       *dst_len = stream.total_out;
+#endif
+       return;
+}
+
+/******************************************************************************/
+/*                            lzo1 compression                                */
+/******************************************************************************/
+
+static int lzo1_init(void)
+{
+       int ret;
+       ret = lzo_init();
+       if (ret != LZO_E_OK)
+               warning("edward-848", "lzo_init() failed with ret = %d\n", ret);
+       return ret;
+}
+
+static int lzo1_overrun(unsigned in_len)
+{
+       return in_len / 64 + 16 + 3;
+}
+
+#define LZO_HEAP_SIZE(size) \
+       sizeof(lzo_align_t) * (((size) + (sizeof(lzo_align_t) - 1)) / sizeof(lzo_align_t))
+
+static coa_t lzo1_alloc(tfm_action act)
+{
+       int ret = 0;
+       coa_t coa = NULL;
+
+       switch (act) {
+       case TFMA_WRITE:        /* compress */
+               coa = reiser4_vmalloc(LZO_HEAP_SIZE(LZO1X_1_MEM_COMPRESS));
+               if (!coa) {
+                       ret = -ENOMEM;
+                       break;
+               }
+               memset(coa, 0, LZO_HEAP_SIZE(LZO1X_1_MEM_COMPRESS));
+       case TFMA_READ:         /* decompress */
+               break;
+       default:
+               impossible("edward-877",
+                          "trying to alloc workspace for unknown tfm action");
+       }
+       if (ret) {
+               warning("edward-878",
+                       "alloc workspace for lzo1 (tfm action = %d) failed\n",
+                       act);
+               return ERR_PTR(ret);
+       }
+       return coa;
+}
+
+static void lzo1_free(coa_t coa, tfm_action act)
+{
+       assert("edward-879", coa != NULL);
+
+       switch (act) {
+       case TFMA_WRITE:        /* compress */
+               vfree(coa);
+               break;
+       case TFMA_READ:         /* decompress */
+               impossible("edward-1304",
+                          "trying to free non-allocated workspace");
+       default:
+               impossible("edward-880", "unknown tfm action");
+       }
+       return;
+}
+
+static int lzo1_min_size_deflate(void)
+{
+       return 256;
+}
+
+static void
+lzo1_compress(coa_t coa, __u8 * src_first, unsigned src_len,
+             __u8 * dst_first, unsigned *dst_len)
+{
+       int result;
+
+       assert("edward-846", coa != NULL);
+       assert("edward-847", src_len != 0);
+
+       result = lzo1x_1_compress(src_first, src_len, dst_first, dst_len, coa);
+       if (result != LZO_E_OK) {
+               warning("edward-849", "lzo1x_1_compress failed\n");
+               goto out;
+       }
+       if (*dst_len >= src_len) {
+               //warning("edward-850", "lzo1x_1_compress: incompressible data\n");
+               goto out;
+       }
+       return;
+      out:
+       *dst_len = src_len;
+       return;
+}
+
+static void
+lzo1_decompress(coa_t coa, __u8 * src_first, unsigned src_len,
+               __u8 * dst_first, unsigned *dst_len)
+{
+       int result;
+
+       assert("edward-851", coa == NULL);
+       assert("edward-852", src_len != 0);
+
+       result = lzo1x_decompress(src_first, src_len, dst_first, dst_len, NULL);
+       if (result != LZO_E_OK)
+               warning("edward-853", "lzo1x_1_decompress failed\n");
+       return;
+}
+
+compression_plugin compression_plugins[LAST_COMPRESSION_ID] = {
+       [LZO1_COMPRESSION_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_PLUGIN_TYPE,
+                       .id = LZO1_COMPRESSION_ID,
+                       .pops = &compression_plugin_ops,
+                       .label = "lzo1",
+                       .desc = "lzo1 compression transform",
+                       .linkage = {NULL, NULL}
+               },
+               .init = lzo1_init,
+               .overrun = lzo1_overrun,
+               .alloc = lzo1_alloc,
+               .free = lzo1_free,
+               .min_size_deflate = lzo1_min_size_deflate,
+               .checksum = reiser4_adler32,
+               .compress = lzo1_compress,
+               .decompress = lzo1_decompress
+       },
+       [GZIP1_COMPRESSION_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_PLUGIN_TYPE,
+                       .id = GZIP1_COMPRESSION_ID,
+                       .pops = &compression_plugin_ops,
+                       .label = "gzip1",
+                       .desc = "gzip1 compression transform",
+                       .linkage = {NULL, NULL}
+               },
+               .init = gzip1_init,
+               .overrun = gzip1_overrun,
+               .alloc = gzip1_alloc,
+               .free = gzip1_free,
+               .min_size_deflate = gzip1_min_size_deflate,
+               .checksum = reiser4_adler32,
+               .compress = gzip1_compress,
+               .decompress = gzip1_decompress
+       }
+};
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 120
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/compress.h linux-2.6.20/fs/reiser4/plugin/compress/compress.h
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/compress.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/compress.h  2007-05-06 14:50:43.746990723 +0400
@@ -0,0 +1,38 @@
+#if !defined( __FS_REISER4_COMPRESS_H__ )
+#define __FS_REISER4_COMPRESS_H__
+
+#include <linux/types.h>
+#include <linux/string.h>
+
+typedef enum {
+       TFMA_READ,
+       TFMA_WRITE,
+       TFMA_LAST
+} tfm_action;
+
+/* builtin compression plugins */
+
+typedef enum {
+       LZO1_COMPRESSION_ID,
+       GZIP1_COMPRESSION_ID,
+       LAST_COMPRESSION_ID,
+} reiser4_compression_id;
+
+typedef unsigned long cloff_t;
+typedef void *coa_t;
+typedef coa_t coa_set[LAST_COMPRESSION_ID][TFMA_LAST];
+
+__u32 reiser4_adler32(char *data, __u32 len);
+
+#endif                         /* __FS_REISER4_COMPRESS_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/compress_mode.c linux-2.6.20/fs/reiser4/plugin/compress/compress_mode.c
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/compress_mode.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/compress_mode.c     2007-05-06 14:50:43.750991972 +0400
@@ -0,0 +1,162 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* This file contains Reiser4 compression mode plugins.
+
+   Compression mode plugin is a set of handlers called by compressor
+   at flush time and represent some heuristics including the ones
+   which are to avoid compression of incompressible data, see
+   http://www.namesys.com/cryptcompress_design.html for more details.
+*/
+#include "../../inode.h"
+#include "../plugin.h"
+
+static int should_deflate_none(struct inode * inode, cloff_t index)
+{
+       return 0;
+}
+
+static int should_deflate_common(struct inode * inode, cloff_t index)
+{
+       return compression_is_on(cryptcompress_inode_data(inode));
+}
+
+static int discard_hook_ultim(struct inode *inode, cloff_t index)
+{
+       turn_off_compression(cryptcompress_inode_data(inode));
+       return 0;
+}
+
+static int discard_hook_lattd(struct inode *inode, cloff_t index)
+{
+       cryptcompress_info_t * info = cryptcompress_inode_data(inode);
+
+       assert("edward-1462",
+              get_lattice_factor(info) >= MIN_LATTICE_FACTOR &&
+              get_lattice_factor(info) <= MAX_LATTICE_FACTOR);
+
+       turn_off_compression(info);
+       if (get_lattice_factor(info) < MAX_LATTICE_FACTOR)
+               set_lattice_factor(info, get_lattice_factor(info) << 1);
+       return 0;
+}
+
+static int accept_hook_lattd(struct inode *inode, cloff_t index)
+{
+       turn_on_compression(cryptcompress_inode_data(inode));
+       set_lattice_factor(cryptcompress_inode_data(inode), MIN_LATTICE_FACTOR);
+       return 0;
+}
+
+/* Check on dynamic lattice, the adaptive compression modes which
+   defines the following behavior:
+
+   Compression is on: try to compress everything and turn
+   it off, whenever cluster is incompressible.
+
+   Compression is off: try to compress clusters of indexes
+   k * FACTOR (k = 0, 1, 2, ...) and turn it on, if some of
+   them is compressible. If incompressible, then increase FACTOR */
+
+/* check if @index belongs to one-dimensional lattice
+   of sparce factor @factor */
+static int is_on_lattice(cloff_t index, int factor)
+{
+       return (factor ? index % factor == 0: index == 0);
+}
+
+static int should_deflate_lattd(struct inode * inode, cloff_t index)
+{
+       return should_deflate_common(inode, index) ||
+               is_on_lattice(index,
+                             get_lattice_factor
+                             (cryptcompress_inode_data(inode)));
+}
+
+/* compression mode_plugins */
+compression_mode_plugin compression_mode_plugins[LAST_COMPRESSION_MODE_ID] = {
+       [NONE_COMPRESSION_MODE_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+                       .id = NONE_COMPRESSION_MODE_ID,
+                       .pops = NULL,
+                       .label = "none",
+                       .desc = "Compress nothing",
+                       .linkage = {NULL, NULL}
+               },
+               .should_deflate = should_deflate_none,
+               .accept_hook = NULL,
+               .discard_hook = NULL
+       },
+       /* Check-on-dynamic-lattice adaptive compression mode */
+       [LATTD_COMPRESSION_MODE_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+                       .id = LATTD_COMPRESSION_MODE_ID,
+                       .pops = NULL,
+                       .label = "lattd",
+                       .desc = "Check on dynamic lattice",
+                       .linkage = {NULL, NULL}
+               },
+               .should_deflate = should_deflate_lattd,
+               .accept_hook = accept_hook_lattd,
+               .discard_hook = discard_hook_lattd
+       },
+       /* Check-ultimately compression mode:
+          Turn off compression forever as soon as we meet
+          incompressible data */
+       [ULTIM_COMPRESSION_MODE_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+                       .id = ULTIM_COMPRESSION_MODE_ID,
+                       .pops = NULL,
+                       .label = "ultim",
+                       .desc = "Check ultimately",
+                       .linkage = {NULL, NULL}
+               },
+               .should_deflate = should_deflate_common,
+               .accept_hook = NULL,
+               .discard_hook = discard_hook_ultim
+       },
+       /* Force-to-compress-everything compression mode */
+       [FORCE_COMPRESSION_MODE_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+                       .id = FORCE_COMPRESSION_MODE_ID,
+                       .pops = NULL,
+                       .label = "force",
+                       .desc = "Force to compress everything",
+                       .linkage = {NULL, NULL}
+               },
+               .should_deflate = NULL,
+               .accept_hook = NULL,
+               .discard_hook = NULL
+       },
+       /* Convert-to-extent compression mode.
+          In this mode items will be converted to extents and management
+          will be passed to (classic) unix file plugin as soon as ->write()
+          detects that the first complete logical cluster (of index #0) is
+          incompressible. */
+       [CONVX_COMPRESSION_MODE_ID] = {
+               .h = {
+                       .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+                       .id = CONVX_COMPRESSION_MODE_ID,
+                       .pops = NULL,
+                       .label = "conv",
+                       .desc = "Convert to extent",
+                       .linkage = {NULL, NULL}
+               },
+               .should_deflate = should_deflate_common,
+               .accept_hook = NULL,
+               .discard_hook = NULL
+       }
+};
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 120
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/lzoconf.h linux-2.6.20/fs/reiser4/plugin/compress/lzoconf.h
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/lzoconf.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/lzoconf.h   2007-05-06 14:50:43.750991972 +0400
@@ -0,0 +1,216 @@
+/* lzoconf.h -- configuration for the LZO real-time data compression library
+   adopted for reiser4 compression transform plugin.
+
+   This file is part of the LZO real-time data compression library
+   and not included in any proprietary licenses of reiser4.
+
+   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
+   All Rights Reserved.
+
+   The LZO library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   The LZO library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the LZO library; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+   Markus F.X.J. Oberhumer
+   <markus@oberhumer.com>
+   http://www.oberhumer.com/opensource/lzo/
+ */
+
+#include <linux/kernel.h>      /* for UINT_MAX, ULONG_MAX - edward */
+
+#ifndef __LZOCONF_H
+#define __LZOCONF_H
+
+#define LZO_VERSION             0x1080
+#define LZO_VERSION_STRING      "1.08"
+#define LZO_VERSION_DATE        "Jul 12 2002"
+
+/* internal Autoconf configuration file - only used when building LZO */
+
+/***********************************************************************
+// LZO requires a conforming <limits.h>
+************************************************************************/
+
+#define CHAR_BIT  8
+#define USHRT_MAX 0xffff
+
+/* workaround a cpp bug under hpux 10.20 */
+#define LZO_0xffffffffL         4294967295ul
+
+/***********************************************************************
+// architecture defines
+************************************************************************/
+
+#if !defined(__LZO_i386)
+#  if defined(__i386__) || defined(__386__) || defined(_M_IX86)
+#    define __LZO_i386
+#  endif
+#endif
+
+/* memory checkers */
+#if !defined(__LZO_CHECKER)
+#  if defined(__BOUNDS_CHECKING_ON)
+#    define __LZO_CHECKER
+#  elif defined(__CHECKER__)
+#    define __LZO_CHECKER
+#  elif defined(__INSURE__)
+#    define __LZO_CHECKER
+#  elif defined(__PURIFY__)
+#    define __LZO_CHECKER
+#  endif
+#endif
+
+/***********************************************************************
+// integral and pointer types
+************************************************************************/
+
+/* Integral types with 32 bits or more */
+#if !defined(LZO_UINT32_MAX)
+#  if (UINT_MAX >= LZO_0xffffffffL)
+       typedef unsigned int lzo_uint32;
+       typedef int lzo_int32;
+#    define LZO_UINT32_MAX      UINT_MAX
+#    define LZO_INT32_MAX       INT_MAX
+#    define LZO_INT32_MIN       INT_MIN
+#  elif (ULONG_MAX >= LZO_0xffffffffL)
+       typedef unsigned long lzo_uint32;
+       typedef long lzo_int32;
+#    define LZO_UINT32_MAX      ULONG_MAX
+#    define LZO_INT32_MAX       LONG_MAX
+#    define LZO_INT32_MIN       LONG_MIN
+#  else
+#    error "lzo_uint32"
+#  endif
+#endif
+
+/* lzo_uint is used like size_t */
+#if !defined(LZO_UINT_MAX)
+#  if (UINT_MAX >= LZO_0xffffffffL)
+       typedef unsigned int lzo_uint;
+       typedef int lzo_int;
+#    define LZO_UINT_MAX        UINT_MAX
+#    define LZO_INT_MAX         INT_MAX
+#    define LZO_INT_MIN         INT_MIN
+#  elif (ULONG_MAX >= LZO_0xffffffffL)
+       typedef unsigned long lzo_uint;
+       typedef long lzo_int;
+#    define LZO_UINT_MAX        ULONG_MAX
+#    define LZO_INT_MAX         LONG_MAX
+#    define LZO_INT_MIN         LONG_MIN
+#  else
+#    error "lzo_uint"
+#  endif
+#endif
+
+       typedef int lzo_bool;
+
+/***********************************************************************
+// memory models
+************************************************************************/
+
+/* Memory model that allows to access memory at offsets of lzo_uint. */
+#if !defined(__LZO_MMODEL)
+#  if (LZO_UINT_MAX <= UINT_MAX)
+#    define __LZO_MMODEL
+#  else
+#    error "__LZO_MMODEL"
+#  endif
+#endif
+
+/* no typedef here because of const-pointer issues */
+#define lzo_byte                unsigned char __LZO_MMODEL
+#define lzo_bytep               unsigned char __LZO_MMODEL *
+#define lzo_charp               char __LZO_MMODEL *
+#define lzo_voidp               void __LZO_MMODEL *
+#define lzo_shortp              short __LZO_MMODEL *
+#define lzo_ushortp             unsigned short __LZO_MMODEL *
+#define lzo_uint32p             lzo_uint32 __LZO_MMODEL *
+#define lzo_int32p              lzo_int32 __LZO_MMODEL *
+#define lzo_uintp               lzo_uint __LZO_MMODEL *
+#define lzo_intp                lzo_int __LZO_MMODEL *
+#define lzo_voidpp              lzo_voidp __LZO_MMODEL *
+#define lzo_bytepp              lzo_bytep __LZO_MMODEL *
+
+#ifndef lzo_sizeof_dict_t
+#  define lzo_sizeof_dict_t     sizeof(lzo_bytep)
+#endif
+
+typedef int (*lzo_compress_t) (const lzo_byte * src, lzo_uint src_len,
+                              lzo_byte * dst, lzo_uintp dst_len,
+                              lzo_voidp wrkmem);
+
+
+/***********************************************************************
+// error codes and prototypes
+************************************************************************/
+
+/* Error codes for the compression/decompression functions. Negative
+ * values are errors, positive values will be used for special but
+ * normal events.
+ */
+#define LZO_E_OK                    0
+#define LZO_E_ERROR                 (-1)
+#define LZO_E_OUT_OF_MEMORY         (-2)       /* not used right now */
+#define LZO_E_NOT_COMPRESSIBLE      (-3)       /* not used right now */
+#define LZO_E_INPUT_OVERRUN         (-4)
+#define LZO_E_OUTPUT_OVERRUN        (-5)
+#define LZO_E_LOOKBEHIND_OVERRUN    (-6)
+#define LZO_E_EOF_NOT_FOUND         (-7)
+#define LZO_E_INPUT_NOT_CONSUMED    (-8)
+
+/* lzo_init() should be the first function you call.
+ * Check the return code !
+ *
+ * lzo_init() is a macro to allow checking that the library and the
+ * compiler's view of various types are consistent.
+ */
+#define lzo_init() __lzo_init2(LZO_VERSION,(int)sizeof(short),(int)sizeof(int),\
+    (int)sizeof(long),(int)sizeof(lzo_uint32),(int)sizeof(lzo_uint),\
+    (int)lzo_sizeof_dict_t,(int)sizeof(char *),(int)sizeof(lzo_voidp),\
+    (int)sizeof(lzo_compress_t))
+        extern int __lzo_init2(unsigned, int, int, int, int, int, int,
+                               int, int, int);
+
+/* checksum functions */
+extern lzo_uint32 lzo_crc32(lzo_uint32 _c, const lzo_byte * _buf,
+                           lzo_uint _len);
+/* misc. */
+       typedef union {
+               lzo_bytep p;
+               lzo_uint u;
+       } __lzo_pu_u;
+       typedef union {
+               lzo_bytep p;
+               lzo_uint32 u32;
+       } __lzo_pu32_u;
+       typedef union {
+               void *vp;
+               lzo_bytep bp;
+               lzo_uint32 u32;
+               long l;
+       } lzo_align_t;
+
+#define LZO_PTR_ALIGN_UP(_ptr,_size) \
+    ((_ptr) + (lzo_uint) __lzo_align_gap((const lzo_voidp)(_ptr),(lzo_uint)(_size)))
+
+/* deprecated - only for backward compatibility */
+#define LZO_ALIGN(_ptr,_size) LZO_PTR_ALIGN_UP(_ptr,_size)
+
+#endif                         /* already included */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/Makefile linux-2.6.20/fs/reiser4/plugin/compress/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/Makefile       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/Makefile    2007-05-06 14:50:43.750991972 +0400
@@ -0,0 +1,6 @@
+obj-$(CONFIG_REISER4_FS) += compress_plugins.o
+
+compress_plugins-objs :=       \
+       compress.o              \
+       minilzo.o               \
+       compress_mode.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/minilzo.c linux-2.6.20/fs/reiser4/plugin/compress/minilzo.c
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/minilzo.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/minilzo.c   2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,1967 @@
+/* minilzo.c -- mini subset of the LZO real-time data compression library
+   adopted for reiser4 compression transform plugin.
+
+   This file is part of the LZO real-time data compression library
+   and not included in any proprietary licenses of reiser4.
+
+   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
+   All Rights Reserved.
+
+   The LZO library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   The LZO library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the LZO library; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+   Markus F.X.J. Oberhumer
+   <markus@oberhumer.com>
+   http://www.oberhumer.com/opensource/lzo/
+ */
+
+/*
+ * NOTE:
+ *   the full LZO package can be found at
+ *   http://www.oberhumer.com/opensource/lzo/
+ */
+
+#include "../../debug.h"       /* for reiser4 assert macro -edward */
+
+#define __LZO_IN_MINILZO
+#define LZO_BUILD
+
+#include "minilzo.h"
+
+#if !defined(MINILZO_VERSION) || (MINILZO_VERSION != 0x1080)
+#  error "version mismatch in miniLZO source files"
+#endif
+
+#ifndef __LZO_CONF_H
+#define __LZO_CONF_H
+
+#  define BOUNDS_CHECKING_OFF_DURING(stmt)      stmt
+#  define BOUNDS_CHECKING_OFF_IN_EXPR(expr)     (expr)
+
+#  define HAVE_MEMCMP
+#  define HAVE_MEMCPY
+#  define HAVE_MEMMOVE
+#  define HAVE_MEMSET
+
+#undef NDEBUG
+#if !defined(LZO_DEBUG)
+#  define NDEBUG
+#endif
+#if defined(LZO_DEBUG) || !defined(NDEBUG)
+#  if !defined(NO_STDIO_H)
+#    include <stdio.h>
+#  endif
+#endif
+
+#if !defined(LZO_COMPILE_TIME_ASSERT)
+#  define LZO_COMPILE_TIME_ASSERT(expr) \
+       { typedef int __lzo_compile_time_assert_fail[1 - 2 * !(expr)]; }
+#endif
+
+#if !defined(LZO_UNUSED)
+#  if 1
+#    define LZO_UNUSED(var)     ((void)&var)
+#  elif 0
+#    define LZO_UNUSED(var)     { typedef int __lzo_unused[sizeof(var) ? 2 : 1]; }
+#  else
+#    define LZO_UNUSED(parm)    (parm = parm)
+#  endif
+#endif
+
+#if defined(NO_MEMCMP)
+#  undef HAVE_MEMCMP
+#endif
+
+#if !defined(HAVE_MEMSET)
+#  undef memset
+#  define memset    lzo_memset
+#endif
+
+#  define LZO_BYTE(x)       ((unsigned char) ((x) & 0xff))
+
+#define LZO_MAX(a,b)        ((a) >= (b) ? (a) : (b))
+#define LZO_MIN(a,b)        ((a) <= (b) ? (a) : (b))
+#define LZO_MAX3(a,b,c)     ((a) >= (b) ? LZO_MAX(a,c) : LZO_MAX(b,c))
+#define LZO_MIN3(a,b,c)     ((a) <= (b) ? LZO_MIN(a,c) : LZO_MIN(b,c))
+
+#define lzo_sizeof(type)    ((lzo_uint) (sizeof(type)))
+
+#define LZO_HIGH(array)     ((lzo_uint) (sizeof(array)/sizeof(*(array))))
+
+#define LZO_SIZE(bits)      (1u << (bits))
+#define LZO_MASK(bits)      (LZO_SIZE(bits) - 1)
+
+#define LZO_LSIZE(bits)     (1ul << (bits))
+#define LZO_LMASK(bits)     (LZO_LSIZE(bits) - 1)
+
+#define LZO_USIZE(bits)     ((lzo_uint) 1 << (bits))
+#define LZO_UMASK(bits)     (LZO_USIZE(bits) - 1)
+
+#define LZO_STYPE_MAX(b)    (((1l  << (8*(b)-2)) - 1l)  + (1l  << (8*(b)-2)))
+#define LZO_UTYPE_MAX(b)    (((1ul << (8*(b)-1)) - 1ul) + (1ul << (8*(b)-1)))
+
+#if !defined(SIZEOF_UNSIGNED)
+#  if (UINT_MAX == 0xffff)
+#    define SIZEOF_UNSIGNED         2
+#  elif (UINT_MAX == LZO_0xffffffffL)
+#    define SIZEOF_UNSIGNED         4
+#  elif (UINT_MAX >= LZO_0xffffffffL)
+#    define SIZEOF_UNSIGNED         8
+#  else
+#    error "SIZEOF_UNSIGNED"
+#  endif
+#endif
+
+#if !defined(SIZEOF_UNSIGNED_LONG)
+#  if (ULONG_MAX == LZO_0xffffffffL)
+#    define SIZEOF_UNSIGNED_LONG    4
+#  elif (ULONG_MAX >= LZO_0xffffffffL)
+#    define SIZEOF_UNSIGNED_LONG    8
+#  else
+#    error "SIZEOF_UNSIGNED_LONG"
+#  endif
+#endif
+
+#if !defined(SIZEOF_SIZE_T)
+#  define SIZEOF_SIZE_T             SIZEOF_UNSIGNED
+#endif
+#if !defined(SIZE_T_MAX)
+#  define SIZE_T_MAX                LZO_UTYPE_MAX(SIZEOF_SIZE_T)
+#endif
+
+#if 1 && defined(__LZO_i386) && (UINT_MAX == LZO_0xffffffffL)
+#  if !defined(LZO_UNALIGNED_OK_2) && (USHRT_MAX == 0xffff)
+#    define LZO_UNALIGNED_OK_2
+#  endif
+#  if !defined(LZO_UNALIGNED_OK_4) && (LZO_UINT32_MAX == LZO_0xffffffffL)
+#    define LZO_UNALIGNED_OK_4
+#  endif
+#endif
+
+#if defined(LZO_UNALIGNED_OK_2) || defined(LZO_UNALIGNED_OK_4)
+#  if !defined(LZO_UNALIGNED_OK)
+#    define LZO_UNALIGNED_OK
+#  endif
+#endif
+
+#if defined(__LZO_NO_UNALIGNED)
+#  undef LZO_UNALIGNED_OK
+#  undef LZO_UNALIGNED_OK_2
+#  undef LZO_UNALIGNED_OK_4
+#endif
+
+#if defined(LZO_UNALIGNED_OK_2) && (USHRT_MAX != 0xffff)
+#  error "LZO_UNALIGNED_OK_2 must not be defined on this system"
+#endif
+#if defined(LZO_UNALIGNED_OK_4) && (LZO_UINT32_MAX != LZO_0xffffffffL)
+#  error "LZO_UNALIGNED_OK_4 must not be defined on this system"
+#endif
+
+#if defined(__LZO_NO_ALIGNED)
+#  undef LZO_ALIGNED_OK_4
+#endif
+
+#if defined(LZO_ALIGNED_OK_4) && (LZO_UINT32_MAX != LZO_0xffffffffL)
+#  error "LZO_ALIGNED_OK_4 must not be defined on this system"
+#endif
+
+#define LZO_LITTLE_ENDIAN       1234
+#define LZO_BIG_ENDIAN          4321
+#define LZO_PDP_ENDIAN          3412
+
+#if !defined(LZO_BYTE_ORDER)
+#  if defined(MFX_BYTE_ORDER)
+#    define LZO_BYTE_ORDER      MFX_BYTE_ORDER
+#  elif defined(__LZO_i386)
+#    define LZO_BYTE_ORDER      LZO_LITTLE_ENDIAN
+#  elif defined(BYTE_ORDER)
+#    define LZO_BYTE_ORDER      BYTE_ORDER
+#  elif defined(__BYTE_ORDER)
+#    define LZO_BYTE_ORDER      __BYTE_ORDER
+#  endif
+#endif
+
+#if defined(LZO_BYTE_ORDER)
+#  if (LZO_BYTE_ORDER != LZO_LITTLE_ENDIAN) && \
+      (LZO_BYTE_ORDER != LZO_BIG_ENDIAN)
+#    error "invalid LZO_BYTE_ORDER"
+#  endif
+#endif
+
+#if defined(LZO_UNALIGNED_OK) && !defined(LZO_BYTE_ORDER)
+#  error "LZO_BYTE_ORDER is not defined"
+#endif
+
+#define LZO_OPTIMIZE_GNUC_i386_IS_BUGGY
+
+#if defined(NDEBUG) && !defined(LZO_DEBUG) && !defined(__LZO_CHECKER)
+#  if defined(__GNUC__) && defined(__i386__)
+#    if !defined(LZO_OPTIMIZE_GNUC_i386_IS_BUGGY)
+#      define LZO_OPTIMIZE_GNUC_i386
+#    endif
+#  endif
+#endif
+
+extern const lzo_uint32 _lzo_crc32_table[256];
+
+#define _LZO_STRINGIZE(x)           #x
+#define _LZO_MEXPAND(x)             _LZO_STRINGIZE(x)
+
+#define _LZO_CONCAT2(a,b)           a ## b
+#define _LZO_CONCAT3(a,b,c)         a ## b ## c
+#define _LZO_CONCAT4(a,b,c,d)       a ## b ## c ## d
+#define _LZO_CONCAT5(a,b,c,d,e)     a ## b ## c ## d ## e
+
+#define _LZO_ECONCAT2(a,b)          _LZO_CONCAT2(a,b)
+#define _LZO_ECONCAT3(a,b,c)        _LZO_CONCAT3(a,b,c)
+#define _LZO_ECONCAT4(a,b,c,d)      _LZO_CONCAT4(a,b,c,d)
+#define _LZO_ECONCAT5(a,b,c,d,e)    _LZO_CONCAT5(a,b,c,d,e)
+
+#ifndef __LZO_PTR_H
+#define __LZO_PTR_H
+
+#if !defined(lzo_ptrdiff_t)
+#  if (UINT_MAX >= LZO_0xffffffffL)
+typedef ptrdiff_t lzo_ptrdiff_t;
+#  else
+typedef long lzo_ptrdiff_t;
+#  endif
+#endif
+
+#if !defined(__LZO_HAVE_PTR_T)
+#  if defined(lzo_ptr_t)
+#    define __LZO_HAVE_PTR_T
+#  endif
+#endif
+#if !defined(__LZO_HAVE_PTR_T)
+#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_LONG)
+#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_LONG)
+typedef unsigned long lzo_ptr_t;
+typedef long lzo_sptr_t;
+#      define __LZO_HAVE_PTR_T
+#    endif
+#  endif
+#endif
+#if !defined(__LZO_HAVE_PTR_T)
+#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED)
+#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED)
+typedef unsigned int lzo_ptr_t;
+typedef int lzo_sptr_t;
+#      define __LZO_HAVE_PTR_T
+#    endif
+#  endif
+#endif
+#if !defined(__LZO_HAVE_PTR_T)
+#  if defined(SIZEOF_CHAR_P) && defined(SIZEOF_UNSIGNED_SHORT)
+#    if (SIZEOF_CHAR_P == SIZEOF_UNSIGNED_SHORT)
+typedef unsigned short lzo_ptr_t;
+typedef short lzo_sptr_t;
+#      define __LZO_HAVE_PTR_T
+#    endif
+#  endif
+#endif
+#if !defined(__LZO_HAVE_PTR_T)
+#  if defined(LZO_HAVE_CONFIG_H) || defined(SIZEOF_CHAR_P)
+#    error "no suitable type for lzo_ptr_t"
+#  else
+typedef unsigned long lzo_ptr_t;
+typedef long lzo_sptr_t;
+#    define __LZO_HAVE_PTR_T
+#  endif
+#endif
+
+#define PTR(a)              ((lzo_ptr_t) (a))
+#define PTR_LINEAR(a)       PTR(a)
+#define PTR_ALIGNED_4(a)    ((PTR_LINEAR(a) & 3) == 0)
+#define PTR_ALIGNED_8(a)    ((PTR_LINEAR(a) & 7) == 0)
+#define PTR_ALIGNED2_4(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 3) == 0)
+#define PTR_ALIGNED2_8(a,b) (((PTR_LINEAR(a) | PTR_LINEAR(b)) & 7) == 0)
+
+#define PTR_LT(a,b)         (PTR(a) < PTR(b))
+#define PTR_GE(a,b)         (PTR(a) >= PTR(b))
+#define PTR_DIFF(a,b)       ((lzo_ptrdiff_t) (PTR(a) - PTR(b)))
+#define pd(a,b)             ((lzo_uint) ((a)-(b)))
+
+typedef union {
+       char a_char;
+       unsigned char a_uchar;
+       short a_short;
+       unsigned short a_ushort;
+       int a_int;
+       unsigned int a_uint;
+       long a_long;
+       unsigned long a_ulong;
+       lzo_int a_lzo_int;
+       lzo_uint a_lzo_uint;
+       lzo_int32 a_lzo_int32;
+       lzo_uint32 a_lzo_uint32;
+       ptrdiff_t a_ptrdiff_t;
+       lzo_ptrdiff_t a_lzo_ptrdiff_t;
+       lzo_ptr_t a_lzo_ptr_t;
+       lzo_voidp a_lzo_voidp;
+       void *a_void_p;
+       lzo_bytep a_lzo_bytep;
+       lzo_bytepp a_lzo_bytepp;
+       lzo_uintp a_lzo_uintp;
+       lzo_uint *a_lzo_uint_p;
+       lzo_uint32p a_lzo_uint32p;
+       lzo_uint32 *a_lzo_uint32_p;
+       unsigned char *a_uchar_p;
+       char *a_char_p;
+} lzo_full_align_t;
+
+#endif
+#define LZO_DETERMINISTIC
+#define LZO_DICT_USE_PTR
+#  define lzo_dict_t    const lzo_bytep
+#  define lzo_dict_p    lzo_dict_t __LZO_MMODEL *
+#if !defined(lzo_moff_t)
+#define lzo_moff_t      lzo_uint
+#endif
+#endif
+static lzo_ptr_t __lzo_ptr_linear(const lzo_voidp ptr)
+{
+       return PTR_LINEAR(ptr);
+}
+
+static unsigned __lzo_align_gap(const lzo_voidp ptr, lzo_uint size)
+{
+       lzo_ptr_t p, s, n;
+
+       assert("lzo-01", size > 0);
+
+       p = __lzo_ptr_linear(ptr);
+       s = (lzo_ptr_t) (size - 1);
+       n = (((p + s) / size) * size) - p;
+
+       assert("lzo-02", (long)n >= 0);
+       assert("lzo-03", n <= s);
+
+       return (unsigned)n;
+}
+
+#ifndef __LZO_UTIL_H
+#define __LZO_UTIL_H
+
+#ifndef __LZO_CONF_H
+#endif
+
+#if 1 && defined(HAVE_MEMCPY)
+#define MEMCPY8_DS(dest,src,len) \
+    memcpy(dest,src,len); \
+    dest += len; \
+    src += len
+#endif
+
+#if !defined(MEMCPY8_DS)
+
+#define MEMCPY8_DS(dest,src,len) \
+    { register lzo_uint __l = (len) / 8; \
+    do { \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+       *dest++ = *src++; \
+    } while (--__l > 0); }
+
+#endif
+
+#define MEMCPY_DS(dest,src,len) \
+    do *dest++ = *src++; \
+    while (--len > 0)
+
+#define MEMMOVE_DS(dest,src,len) \
+    do *dest++ = *src++; \
+    while (--len > 0)
+
+#if (LZO_UINT_MAX <= SIZE_T_MAX) && defined(HAVE_MEMSET)
+
+#define BZERO8_PTR(s,l,n)   memset((s),0,(lzo_uint)(l)*(n))
+
+#else
+
+#define BZERO8_PTR(s,l,n) \
+    lzo_memset((lzo_voidp)(s),0,(lzo_uint)(l)*(n))
+
+#endif
+#endif
+
+/* If you use the LZO library in a product, you *must* keep this
+ * copyright string in the executable of your product.
+ */
+
+static const lzo_byte __lzo_copyright[] =
+#if !defined(__LZO_IN_MINLZO)
+    LZO_VERSION_STRING;
+#else
+    "\n\n\n"
+    "LZO real-time data compression library.\n"
+    "Copyright (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002 Markus Franz Xaver Johannes Oberhumer\n"
+    "<markus.oberhumer@jk.uni-linz.ac.at>\n"
+    "http://www.oberhumer.com/opensource/lzo/\n"
+    "\n"
+    "LZO version: v" LZO_VERSION_STRING ", " LZO_VERSION_DATE "\n"
+    "LZO build date: " __DATE__ " " __TIME__ "\n\n"
+    "LZO special compilation options:\n"
+#ifdef __cplusplus
+    " __cplusplus\n"
+#endif
+#if defined(__PIC__)
+    " __PIC__\n"
+#elif defined(__pic__)
+    " __pic__\n"
+#endif
+#if (UINT_MAX < LZO_0xffffffffL)
+    " 16BIT\n"
+#endif
+#if defined(__LZO_STRICT_16BIT)
+    " __LZO_STRICT_16BIT\n"
+#endif
+#if (UINT_MAX > LZO_0xffffffffL)
+    " UINT_MAX=" _LZO_MEXPAND(UINT_MAX) "\n"
+#endif
+#if (ULONG_MAX > LZO_0xffffffffL)
+    " ULONG_MAX=" _LZO_MEXPAND(ULONG_MAX) "\n"
+#endif
+#if defined(LZO_BYTE_ORDER)
+    " LZO_BYTE_ORDER=" _LZO_MEXPAND(LZO_BYTE_ORDER) "\n"
+#endif
+#if defined(LZO_UNALIGNED_OK_2)
+    " LZO_UNALIGNED_OK_2\n"
+#endif
+#if defined(LZO_UNALIGNED_OK_4)
+    " LZO_UNALIGNED_OK_4\n"
+#endif
+#if defined(LZO_ALIGNED_OK_4)
+    " LZO_ALIGNED_OK_4\n"
+#endif
+#if defined(LZO_DICT_USE_PTR)
+    " LZO_DICT_USE_PTR\n"
+#endif
+#if defined(__LZO_QUERY_COMPRESS)
+    " __LZO_QUERY_COMPRESS\n"
+#endif
+#if defined(__LZO_QUERY_DECOMPRESS)
+    " __LZO_QUERY_DECOMPRESS\n"
+#endif
+#if defined(__LZO_IN_MINILZO)
+    " __LZO_IN_MINILZO\n"
+#endif
+    "\n\n" "$Id: LZO " LZO_VERSION_STRING " built " __DATE__ " " __TIME__
+#if defined(__GNUC__) && defined(__VERSION__)
+    " by gcc " __VERSION__
+#elif defined(__BORLANDC__)
+    " by Borland C " _LZO_MEXPAND(__BORLANDC__)
+#elif defined(_MSC_VER)
+    " by Microsoft C " _LZO_MEXPAND(_MSC_VER)
+#elif defined(__PUREC__)
+    " by Pure C " _LZO_MEXPAND(__PUREC__)
+#elif defined(__SC__)
+    " by Symantec C " _LZO_MEXPAND(__SC__)
+#elif defined(__TURBOC__)
+    " by Turbo C " _LZO_MEXPAND(__TURBOC__)
+#elif defined(__WATCOMC__)
+    " by Watcom C " _LZO_MEXPAND(__WATCOMC__)
+#endif
+    " $\n"
+    "$Copyright: LZO (C) 1996, 1997, 1998, 1999, 2000, 2001, 2002 Markus Franz Xaver Johannes Oberhumer $\n";
+#endif
+
+#define LZO_BASE 65521u
+#define LZO_NMAX 5552
+
+#define LZO_DO1(buf,i)  {s1 += buf[i]; s2 += s1;}
+#define LZO_DO2(buf,i)  LZO_DO1(buf,i); LZO_DO1(buf,i+1);
+#define LZO_DO4(buf,i)  LZO_DO2(buf,i); LZO_DO2(buf,i+2);
+#define LZO_DO8(buf,i)  LZO_DO4(buf,i); LZO_DO4(buf,i+4);
+#define LZO_DO16(buf,i) LZO_DO8(buf,i); LZO_DO8(buf,i+8);
+
+#  define IS_SIGNED(type)       (((type) (-1)) < ((type) 0))
+#  define IS_UNSIGNED(type)     (((type) (-1)) > ((type) 0))
+
+#define IS_POWER_OF_2(x)        (((x) & ((x) - 1)) == 0)
+
+static lzo_bool schedule_insns_bug(void);
+static lzo_bool strength_reduce_bug(int *);
+
+#  define __lzo_assert(x)   ((x) ? 1 : 0)
+
+#undef COMPILE_TIME_ASSERT
+
+#  define COMPILE_TIME_ASSERT(expr)     LZO_COMPILE_TIME_ASSERT(expr)
+
+static lzo_bool basic_integral_check(void)
+{
+       lzo_bool r = 1;
+
+       COMPILE_TIME_ASSERT(CHAR_BIT == 8);
+       COMPILE_TIME_ASSERT(sizeof(char) == 1);
+       COMPILE_TIME_ASSERT(sizeof(short) >= 2);
+       COMPILE_TIME_ASSERT(sizeof(long) >= 4);
+       COMPILE_TIME_ASSERT(sizeof(int) >= sizeof(short));
+       COMPILE_TIME_ASSERT(sizeof(long) >= sizeof(int));
+
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint) == sizeof(lzo_int));
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint32) == sizeof(lzo_int32));
+
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint32) >= 4);
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint32) >= sizeof(unsigned));
+#if defined(__LZO_STRICT_16BIT)
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint) == 2);
+#else
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint) >= 4);
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint) >= sizeof(unsigned));
+#endif
+
+#if (USHRT_MAX == 65535u)
+       COMPILE_TIME_ASSERT(sizeof(short) == 2);
+#elif (USHRT_MAX == LZO_0xffffffffL)
+       COMPILE_TIME_ASSERT(sizeof(short) == 4);
+#elif (USHRT_MAX >= LZO_0xffffffffL)
+       COMPILE_TIME_ASSERT(sizeof(short) > 4);
+#endif
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(unsigned char));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(unsigned short));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(unsigned));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(unsigned long));
+       COMPILE_TIME_ASSERT(IS_SIGNED(short));
+       COMPILE_TIME_ASSERT(IS_SIGNED(int));
+       COMPILE_TIME_ASSERT(IS_SIGNED(long));
+
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(lzo_uint32));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(lzo_uint));
+       COMPILE_TIME_ASSERT(IS_SIGNED(lzo_int32));
+       COMPILE_TIME_ASSERT(IS_SIGNED(lzo_int));
+
+       COMPILE_TIME_ASSERT(INT_MAX == LZO_STYPE_MAX(sizeof(int)));
+       COMPILE_TIME_ASSERT(UINT_MAX == LZO_UTYPE_MAX(sizeof(unsigned)));
+       COMPILE_TIME_ASSERT(LONG_MAX == LZO_STYPE_MAX(sizeof(long)));
+       COMPILE_TIME_ASSERT(ULONG_MAX == LZO_UTYPE_MAX(sizeof(unsigned long)));
+       COMPILE_TIME_ASSERT(USHRT_MAX == LZO_UTYPE_MAX(sizeof(unsigned short)));
+       COMPILE_TIME_ASSERT(LZO_UINT32_MAX ==
+                           LZO_UTYPE_MAX(sizeof(lzo_uint32)));
+       COMPILE_TIME_ASSERT(LZO_UINT_MAX == LZO_UTYPE_MAX(sizeof(lzo_uint)));
+
+       r &= __lzo_assert(LZO_BYTE(257) == 1);
+
+       return r;
+}
+
+static lzo_bool basic_ptr_check(void)
+{
+       lzo_bool r = 1;
+
+       COMPILE_TIME_ASSERT(sizeof(char *) >= sizeof(int));
+       COMPILE_TIME_ASSERT(sizeof(lzo_byte *) >= sizeof(char *));
+
+       COMPILE_TIME_ASSERT(sizeof(lzo_voidp) == sizeof(lzo_byte *));
+       COMPILE_TIME_ASSERT(sizeof(lzo_voidp) == sizeof(lzo_voidpp));
+       COMPILE_TIME_ASSERT(sizeof(lzo_voidp) == sizeof(lzo_bytepp));
+       COMPILE_TIME_ASSERT(sizeof(lzo_voidp) >= sizeof(lzo_uint));
+
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptr_t) == sizeof(lzo_voidp));
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptr_t) == sizeof(lzo_sptr_t));
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptr_t) >= sizeof(lzo_uint));
+
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptrdiff_t) >= 4);
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptrdiff_t) >= sizeof(ptrdiff_t));
+
+       COMPILE_TIME_ASSERT(sizeof(ptrdiff_t) >= sizeof(size_t));
+       COMPILE_TIME_ASSERT(sizeof(lzo_ptrdiff_t) >= sizeof(lzo_uint));
+
+#if defined(SIZEOF_CHAR_P)
+       COMPILE_TIME_ASSERT(SIZEOF_CHAR_P == sizeof(char *));
+#endif
+#if defined(SIZEOF_PTRDIFF_T)
+       COMPILE_TIME_ASSERT(SIZEOF_PTRDIFF_T == sizeof(ptrdiff_t));
+#endif
+
+       COMPILE_TIME_ASSERT(IS_SIGNED(ptrdiff_t));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(size_t));
+       COMPILE_TIME_ASSERT(IS_SIGNED(lzo_ptrdiff_t));
+       COMPILE_TIME_ASSERT(IS_SIGNED(lzo_sptr_t));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(lzo_ptr_t));
+       COMPILE_TIME_ASSERT(IS_UNSIGNED(lzo_moff_t));
+
+       return r;
+}
+
+static lzo_bool ptr_check(void)
+{
+       lzo_bool r = 1;
+       int i;
+       char _wrkmem[10 * sizeof(lzo_byte *) + sizeof(lzo_full_align_t)];
+       lzo_bytep wrkmem;
+       lzo_bytepp dict;
+       unsigned char x[4 * sizeof(lzo_full_align_t)];
+       long d;
+       lzo_full_align_t a;
+       lzo_full_align_t u;
+
+       for (i = 0; i < (int)sizeof(x); i++)
+               x[i] = LZO_BYTE(i);
+
+       wrkmem =
+           LZO_PTR_ALIGN_UP((lzo_byte *) _wrkmem, sizeof(lzo_full_align_t));
+
+       u.a_lzo_bytep = wrkmem;
+       dict = u.a_lzo_bytepp;
+
+       d = (long)((const lzo_bytep)dict - (const lzo_bytep)_wrkmem);
+       r &= __lzo_assert(d >= 0);
+       r &= __lzo_assert(d < (long)sizeof(lzo_full_align_t));
+
+       memset(&a, 0, sizeof(a));
+       r &= __lzo_assert(a.a_lzo_voidp == NULL);
+
+       memset(&a, 0xff, sizeof(a));
+       r &= __lzo_assert(a.a_ushort == USHRT_MAX);
+       r &= __lzo_assert(a.a_uint == UINT_MAX);
+       r &= __lzo_assert(a.a_ulong == ULONG_MAX);
+       r &= __lzo_assert(a.a_lzo_uint == LZO_UINT_MAX);
+       r &= __lzo_assert(a.a_lzo_uint32 == LZO_UINT32_MAX);
+
+       if (r == 1) {
+               for (i = 0; i < 8; i++)
+                       r &= __lzo_assert((const lzo_voidp)(&dict[i]) ==
+                                         (const
+                                          lzo_voidp)(&wrkmem[i *
+                                                             sizeof(lzo_byte
+                                                                    *)]));
+       }
+
+       memset(&a, 0, sizeof(a));
+       r &= __lzo_assert(a.a_char_p == NULL);
+       r &= __lzo_assert(a.a_lzo_bytep == NULL);
+       r &= __lzo_assert(NULL == (void *)0);
+       if (r == 1) {
+               for (i = 0; i < 10; i++)
+                       dict[i] = wrkmem;
+               BZERO8_PTR(dict + 1, sizeof(dict[0]), 8);
+               r &= __lzo_assert(dict[0] == wrkmem);
+               for (i = 1; i < 9; i++)
+                       r &= __lzo_assert(dict[i] == NULL);
+               r &= __lzo_assert(dict[9] == wrkmem);
+       }
+
+       if (r == 1) {
+               unsigned k = 1;
+               const unsigned n = (unsigned)sizeof(lzo_uint32);
+               lzo_byte *p0;
+               lzo_byte *p1;
+
+               k += __lzo_align_gap(&x[k], n);
+               p0 = (lzo_bytep) & x[k];
+#if defined(PTR_LINEAR)
+               r &= __lzo_assert((PTR_LINEAR(p0) & (n - 1)) == 0);
+#else
+               r &= __lzo_assert(n == 4);
+               r &= __lzo_assert(PTR_ALIGNED_4(p0));
+#endif
+
+               r &= __lzo_assert(k >= 1);
+               p1 = (lzo_bytep) & x[1];
+               r &= __lzo_assert(PTR_GE(p0, p1));
+
+               r &= __lzo_assert(k < 1 + n);
+               p1 = (lzo_bytep) & x[1 + n];
+               r &= __lzo_assert(PTR_LT(p0, p1));
+
+               if (r == 1) {
+                       lzo_uint32 v0, v1;
+
+                       u.a_uchar_p = &x[k];
+                       v0 = *u.a_lzo_uint32_p;
+                       u.a_uchar_p = &x[k + n];
+                       v1 = *u.a_lzo_uint32_p;
+
+                       r &= __lzo_assert(v0 > 0);
+                       r &= __lzo_assert(v1 > 0);
+               }
+       }
+
+       return r;
+}
+
+static int _lzo_config_check(void)
+{
+       lzo_bool r = 1;
+       int i;
+       union {
+               lzo_uint32 a;
+               unsigned short b;
+               lzo_uint32 aa[4];
+               unsigned char x[4 * sizeof(lzo_full_align_t)];
+       } u;
+
+       COMPILE_TIME_ASSERT((int)((unsigned char)((signed char)-1)) == 255);
+       COMPILE_TIME_ASSERT((((unsigned char)128) << (int)(8 * sizeof(int) - 8))
+                           < 0);
+
+       r &= basic_integral_check();
+       r &= basic_ptr_check();
+       if (r != 1)
+               return LZO_E_ERROR;
+
+       u.a = 0;
+       u.b = 0;
+       for (i = 0; i < (int)sizeof(u.x); i++)
+               u.x[i] = LZO_BYTE(i);
+
+#if defined(LZO_BYTE_ORDER)
+       if (r == 1) {
+#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
+               lzo_uint32 a = (lzo_uint32) (u.a & LZO_0xffffffffL);
+               unsigned short b = (unsigned short)(u.b & 0xffff);
+               r &= __lzo_assert(a == 0x03020100L);
+               r &= __lzo_assert(b == 0x0100);
+#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
+               lzo_uint32 a = u.a >> (8 * sizeof(u.a) - 32);
+               unsigned short b = u.b >> (8 * sizeof(u.b) - 16);
+               r &= __lzo_assert(a == 0x00010203L);
+               r &= __lzo_assert(b == 0x0001);
+#  else
+#    error "invalid LZO_BYTE_ORDER"
+#  endif
+       }
+#endif
+
+#if defined(LZO_UNALIGNED_OK_2)
+       COMPILE_TIME_ASSERT(sizeof(short) == 2);
+       if (r == 1) {
+               unsigned short b[4];
+
+               for (i = 0; i < 4; i++)
+                       b[i] = *(const unsigned short *)&u.x[i];
+
+#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
+               r &= __lzo_assert(b[0] == 0x0100);
+               r &= __lzo_assert(b[1] == 0x0201);
+               r &= __lzo_assert(b[2] == 0x0302);
+               r &= __lzo_assert(b[3] == 0x0403);
+#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
+               r &= __lzo_assert(b[0] == 0x0001);
+               r &= __lzo_assert(b[1] == 0x0102);
+               r &= __lzo_assert(b[2] == 0x0203);
+               r &= __lzo_assert(b[3] == 0x0304);
+#  endif
+       }
+#endif
+
+#if defined(LZO_UNALIGNED_OK_4)
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint32) == 4);
+       if (r == 1) {
+               lzo_uint32 a[4];
+
+               for (i = 0; i < 4; i++)
+                       a[i] = *(const lzo_uint32 *)&u.x[i];
+
+#  if (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
+               r &= __lzo_assert(a[0] == 0x03020100L);
+               r &= __lzo_assert(a[1] == 0x04030201L);
+               r &= __lzo_assert(a[2] == 0x05040302L);
+               r &= __lzo_assert(a[3] == 0x06050403L);
+#  elif (LZO_BYTE_ORDER == LZO_BIG_ENDIAN)
+               r &= __lzo_assert(a[0] == 0x00010203L);
+               r &= __lzo_assert(a[1] == 0x01020304L);
+               r &= __lzo_assert(a[2] == 0x02030405L);
+               r &= __lzo_assert(a[3] == 0x03040506L);
+#  endif
+       }
+#endif
+
+#if defined(LZO_ALIGNED_OK_4)
+       COMPILE_TIME_ASSERT(sizeof(lzo_uint32) == 4);
+#endif
+
+       COMPILE_TIME_ASSERT(lzo_sizeof_dict_t == sizeof(lzo_dict_t));
+
+       if (r == 1) {
+               r &= __lzo_assert(!schedule_insns_bug());
+       }
+
+       if (r == 1) {
+               static int x[3];
+               static unsigned xn = 3;
+               register unsigned j;
+
+               for (j = 0; j < xn; j++)
+                       x[j] = (int)j - 3;
+               r &= __lzo_assert(!strength_reduce_bug(x));
+       }
+
+       if (r == 1) {
+               r &= ptr_check();
+       }
+
+       return r == 1 ? LZO_E_OK : LZO_E_ERROR;
+}
+
+static lzo_bool schedule_insns_bug(void)
+{
+#if defined(__LZO_CHECKER)
+       return 0;
+#else
+       const int clone[] = { 1, 2, 0 };
+       const int *q;
+       q = clone;
+       return (*q) ? 0 : 1;
+#endif
+}
+
+static lzo_bool strength_reduce_bug(int *x)
+{
+       return x[0] != -3 || x[1] != -2 || x[2] != -1;
+}
+
+#undef COMPILE_TIME_ASSERT
+
+int __lzo_init2(unsigned v, int s1, int s2, int s3, int s4, int s5,
+               int s6, int s7, int s8, int s9)
+{
+       int r;
+
+       if (v == 0)
+               return LZO_E_ERROR;
+
+       r = (s1 == -1 || s1 == (int)sizeof(short)) &&
+           (s2 == -1 || s2 == (int)sizeof(int)) &&
+           (s3 == -1 || s3 == (int)sizeof(long)) &&
+           (s4 == -1 || s4 == (int)sizeof(lzo_uint32)) &&
+           (s5 == -1 || s5 == (int)sizeof(lzo_uint)) &&
+           (s6 == -1 || s6 == (int)lzo_sizeof_dict_t) &&
+           (s7 == -1 || s7 == (int)sizeof(char *)) &&
+           (s8 == -1 || s8 == (int)sizeof(lzo_voidp)) &&
+           (s9 == -1 || s9 == (int)sizeof(lzo_compress_t));
+       if (!r)
+               return LZO_E_ERROR;
+
+       r = _lzo_config_check();
+       if (r != LZO_E_OK)
+               return r;
+
+       return r;
+}
+
+#define do_compress         _lzo1x_1_do_compress
+
+#define LZO_NEED_DICT_H
+#define D_BITS          14
+#define D_INDEX1(d,p)       d = DM((0x21*DX3(p,5,5,6)) >> 5)
+#define D_INDEX2(d,p)       d = (d & (D_MASK & 0x7ff)) ^ (D_HIGH | 0x1f)
+
+#ifndef __LZO_CONFIG1X_H
+#define __LZO_CONFIG1X_H
+
+#if !defined(LZO1X) && !defined(LZO1Y) && !defined(LZO1Z)
+#  define LZO1X
+#endif
+
+#define LZO_EOF_CODE
+#undef LZO_DETERMINISTIC
+
+#define M1_MAX_OFFSET   0x0400
+#ifndef M2_MAX_OFFSET
+#define M2_MAX_OFFSET   0x0800
+#endif
+#define M3_MAX_OFFSET   0x4000
+#define M4_MAX_OFFSET   0xbfff
+
+#define MX_MAX_OFFSET   (M1_MAX_OFFSET + M2_MAX_OFFSET)
+
+#define M1_MIN_LEN      2
+#define M1_MAX_LEN      2
+#define M2_MIN_LEN      3
+#ifndef M2_MAX_LEN
+#define M2_MAX_LEN      8
+#endif
+#define M3_MIN_LEN      3
+#define M3_MAX_LEN      33
+#define M4_MIN_LEN      3
+#define M4_MAX_LEN      9
+
+#define M1_MARKER       0
+#define M2_MARKER       64
+#define M3_MARKER       32
+#define M4_MARKER       16
+
+#ifndef MIN_LOOKAHEAD
+#define MIN_LOOKAHEAD       (M2_MAX_LEN + 1)
+#endif
+
+#if defined(LZO_NEED_DICT_H)
+
+#ifndef LZO_HASH
+#define LZO_HASH            LZO_HASH_LZO_INCREMENTAL_B
+#endif
+#define DL_MIN_LEN          M2_MIN_LEN
+
+#ifndef __LZO_DICT_H
+#define __LZO_DICT_H
+
+#if !defined(D_BITS) && defined(DBITS)
+#  define D_BITS        DBITS
+#endif
+#if !defined(D_BITS)
+#  error "D_BITS is not defined"
+#endif
+#if (D_BITS < 16)
+#  define D_SIZE        LZO_SIZE(D_BITS)
+#  define D_MASK        LZO_MASK(D_BITS)
+#else
+#  define D_SIZE        LZO_USIZE(D_BITS)
+#  define D_MASK        LZO_UMASK(D_BITS)
+#endif
+#define D_HIGH          ((D_MASK >> 1) + 1)
+
+#if !defined(DD_BITS)
+#  define DD_BITS       0
+#endif
+#define DD_SIZE         LZO_SIZE(DD_BITS)
+#define DD_MASK         LZO_MASK(DD_BITS)
+
+#if !defined(DL_BITS)
+#  define DL_BITS       (D_BITS - DD_BITS)
+#endif
+#if (DL_BITS < 16)
+#  define DL_SIZE       LZO_SIZE(DL_BITS)
+#  define DL_MASK       LZO_MASK(DL_BITS)
+#else
+#  define DL_SIZE       LZO_USIZE(DL_BITS)
+#  define DL_MASK       LZO_UMASK(DL_BITS)
+#endif
+
+#if (D_BITS != DL_BITS + DD_BITS)
+#  error "D_BITS does not match"
+#endif
+#if (D_BITS < 8 || D_BITS > 18)
+#  error "invalid D_BITS"
+#endif
+#if (DL_BITS < 8 || DL_BITS > 20)
+#  error "invalid DL_BITS"
+#endif
+#if (DD_BITS < 0 || DD_BITS > 6)
+#  error "invalid DD_BITS"
+#endif
+
+#if !defined(DL_MIN_LEN)
+#  define DL_MIN_LEN    3
+#endif
+#if !defined(DL_SHIFT)
+#  define DL_SHIFT      ((DL_BITS + (DL_MIN_LEN - 1)) / DL_MIN_LEN)
+#endif
+
+#define LZO_HASH_GZIP                   1
+#define LZO_HASH_GZIP_INCREMENTAL       2
+#define LZO_HASH_LZO_INCREMENTAL_A      3
+#define LZO_HASH_LZO_INCREMENTAL_B      4
+
+#if !defined(LZO_HASH)
+#  error "choose a hashing strategy"
+#endif
+
+#if (DL_MIN_LEN == 3)
+#  define _DV2_A(p,shift1,shift2) \
+       (((( (lzo_uint32)((p)[0]) << shift1) ^ (p)[1]) << shift2) ^ (p)[2])
+#  define _DV2_B(p,shift1,shift2) \
+       (((( (lzo_uint32)((p)[2]) << shift1) ^ (p)[1]) << shift2) ^ (p)[0])
+#  define _DV3_B(p,shift1,shift2,shift3) \
+       ((_DV2_B((p)+1,shift1,shift2) << (shift3)) ^ (p)[0])
+#elif (DL_MIN_LEN == 2)
+#  define _DV2_A(p,shift1,shift2) \
+       (( (lzo_uint32)(p[0]) << shift1) ^ p[1])
+#  define _DV2_B(p,shift1,shift2) \
+       (( (lzo_uint32)(p[1]) << shift1) ^ p[2])
+#else
+#  error "invalid DL_MIN_LEN"
+#endif
+#define _DV_A(p,shift)      _DV2_A(p,shift,shift)
+#define _DV_B(p,shift)      _DV2_B(p,shift,shift)
+#define DA2(p,s1,s2) \
+       (((((lzo_uint32)((p)[2]) << (s2)) + (p)[1]) << (s1)) + (p)[0])
+#define DS2(p,s1,s2) \
+       (((((lzo_uint32)((p)[2]) << (s2)) - (p)[1]) << (s1)) - (p)[0])
+#define DX2(p,s1,s2) \
+       (((((lzo_uint32)((p)[2]) << (s2)) ^ (p)[1]) << (s1)) ^ (p)[0])
+#define DA3(p,s1,s2,s3) ((DA2((p)+1,s2,s3) << (s1)) + (p)[0])
+#define DS3(p,s1,s2,s3) ((DS2((p)+1,s2,s3) << (s1)) - (p)[0])
+#define DX3(p,s1,s2,s3) ((DX2((p)+1,s2,s3) << (s1)) ^ (p)[0])
+#define DMS(v,s)        ((lzo_uint) (((v) & (D_MASK >> (s))) << (s)))
+#define DM(v)           DMS(v,0)
+
+#if (LZO_HASH == LZO_HASH_GZIP)
+#  define _DINDEX(dv,p)     (_DV_A((p),DL_SHIFT))
+
+#elif (LZO_HASH == LZO_HASH_GZIP_INCREMENTAL)
+#  define __LZO_HASH_INCREMENTAL
+#  define DVAL_FIRST(dv,p)  dv = _DV_A((p),DL_SHIFT)
+#  define DVAL_NEXT(dv,p)   dv = (((dv) << DL_SHIFT) ^ p[2])
+#  define _DINDEX(dv,p)     (dv)
+#  define DVAL_LOOKAHEAD    DL_MIN_LEN
+
+#elif (LZO_HASH == LZO_HASH_LZO_INCREMENTAL_A)
+#  define __LZO_HASH_INCREMENTAL
+#  define DVAL_FIRST(dv,p)  dv = _DV_A((p),5)
+#  define DVAL_NEXT(dv,p) \
+               dv ^= (lzo_uint32)(p[-1]) << (2*5); dv = (((dv) << 5) ^ p[2])
+#  define _DINDEX(dv,p)     ((0x9f5f * (dv)) >> 5)
+#  define DVAL_LOOKAHEAD    DL_MIN_LEN
+
+#elif (LZO_HASH == LZO_HASH_LZO_INCREMENTAL_B)
+#  define __LZO_HASH_INCREMENTAL
+#  define DVAL_FIRST(dv,p)  dv = _DV_B((p),5)
+#  define DVAL_NEXT(dv,p) \
+               dv ^= p[-1]; dv = (((dv) >> 5) ^ ((lzo_uint32)(p[2]) << (2*5)))
+#  define _DINDEX(dv,p)     ((0x9f5f * (dv)) >> 5)
+#  define DVAL_LOOKAHEAD    DL_MIN_LEN
+
+#else
+#  error "choose a hashing strategy"
+#endif
+
+#ifndef DINDEX
+#define DINDEX(dv,p)        ((lzo_uint)((_DINDEX(dv,p)) & DL_MASK) << DD_BITS)
+#endif
+#if !defined(DINDEX1) && defined(D_INDEX1)
+#define DINDEX1             D_INDEX1
+#endif
+#if !defined(DINDEX2) && defined(D_INDEX2)
+#define DINDEX2             D_INDEX2
+#endif
+
+#if !defined(__LZO_HASH_INCREMENTAL)
+#  define DVAL_FIRST(dv,p)  ((void) 0)
+#  define DVAL_NEXT(dv,p)   ((void) 0)
+#  define DVAL_LOOKAHEAD    0
+#endif
+
+#if !defined(DVAL_ASSERT)
+#if defined(__LZO_HASH_INCREMENTAL) && !defined(NDEBUG)
+static void DVAL_ASSERT(lzo_uint32 dv, const lzo_byte * p)
+{
+       lzo_uint32 df;
+       DVAL_FIRST(df, (p));
+       assert(DINDEX(dv, p) == DINDEX(df, p));
+}
+#else
+#  define DVAL_ASSERT(dv,p) ((void) 0)
+#endif
+#endif
+
+#  define DENTRY(p,in)                          (p)
+#  define GINDEX(m_pos,m_off,dict,dindex,in)    m_pos = dict[dindex]
+
+#if (DD_BITS == 0)
+
+#  define UPDATE_D(dict,drun,dv,p,in)       dict[ DINDEX(dv,p) ] = DENTRY(p,in)
+#  define UPDATE_I(dict,drun,index,p,in)    dict[index] = DENTRY(p,in)
+#  define UPDATE_P(ptr,drun,p,in)           (ptr)[0] = DENTRY(p,in)
+
+#else
+
+#  define UPDATE_D(dict,drun,dv,p,in)   \
+       dict[ DINDEX(dv,p) + drun++ ] = DENTRY(p,in); drun &= DD_MASK
+#  define UPDATE_I(dict,drun,index,p,in)    \
+       dict[ (index) + drun++ ] = DENTRY(p,in); drun &= DD_MASK
+#  define UPDATE_P(ptr,drun,p,in)   \
+       (ptr) [ drun++ ] = DENTRY(p,in); drun &= DD_MASK
+
+#endif
+
+#define LZO_CHECK_MPOS_DET(m_pos,m_off,in,ip,max_offset) \
+       (m_pos == NULL || (m_off = (lzo_moff_t) (ip - m_pos)) > max_offset)
+
+#define LZO_CHECK_MPOS_NON_DET(m_pos,m_off,in,ip,max_offset) \
+    (BOUNDS_CHECKING_OFF_IN_EXPR( \
+       (PTR_LT(m_pos,in) || \
+        (m_off = (lzo_moff_t) PTR_DIFF(ip,m_pos)) <= 0 || \
+         m_off > max_offset) ))
+
+#if defined(LZO_DETERMINISTIC)
+#  define LZO_CHECK_MPOS    LZO_CHECK_MPOS_DET
+#else
+#  define LZO_CHECK_MPOS    LZO_CHECK_MPOS_NON_DET
+#endif
+#endif
+#endif
+#endif
+#define DO_COMPRESS     lzo1x_1_compress
+static
+lzo_uint do_compress(const lzo_byte * in, lzo_uint in_len,
+                    lzo_byte * out, lzo_uintp out_len, lzo_voidp wrkmem)
+{
+       register const lzo_byte *ip;
+       lzo_byte *op;
+       const lzo_byte *const in_end = in + in_len;
+       const lzo_byte *const ip_end = in + in_len - M2_MAX_LEN - 5;
+       const lzo_byte *ii;
+       lzo_dict_p const dict = (lzo_dict_p) wrkmem;
+
+       op = out;
+       ip = in;
+       ii = ip;
+
+       ip += 4;
+       for (;;) {
+               register const lzo_byte *m_pos;
+
+               lzo_moff_t m_off;
+               lzo_uint m_len;
+               lzo_uint dindex;
+
+               DINDEX1(dindex, ip);
+               GINDEX(m_pos, m_off, dict, dindex, in);
+               if (LZO_CHECK_MPOS_NON_DET(m_pos, m_off, in, ip, M4_MAX_OFFSET))
+                       goto literal;
+#if 1
+               if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+                       goto try_match;
+               DINDEX2(dindex, ip);
+#endif
+               GINDEX(m_pos, m_off, dict, dindex, in);
+               if (LZO_CHECK_MPOS_NON_DET(m_pos, m_off, in, ip, M4_MAX_OFFSET))
+                       goto literal;
+               if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+                       goto try_match;
+               goto literal;
+
+             try_match:
+#if 1 && defined(LZO_UNALIGNED_OK_2)
+               if (*(const lzo_ushortp)m_pos != *(const lzo_ushortp)ip) {
+#else
+               if (m_pos[0] != ip[0] || m_pos[1] != ip[1]) {
+#endif
+                       ;
+               } else {
+                       if (m_pos[2] == ip[2]) {
+                               goto match;
+                       } else {
+                               ;
+                       }
+               }
+
+             literal:
+               UPDATE_I(dict, 0, dindex, ip, in);
+               ++ip;
+               if (ip >= ip_end)
+                       break;
+               continue;
+
+             match:
+               UPDATE_I(dict, 0, dindex, ip, in);
+               if (pd(ip, ii) > 0) {
+                       register lzo_uint t = pd(ip, ii);
+
+                       if (t <= 3) {
+                               assert("lzo-04", op - 2 > out);
+                               op[-2] |= LZO_BYTE(t);
+                       } else if (t <= 18)
+                               *op++ = LZO_BYTE(t - 3);
+                       else {
+                               register lzo_uint tt = t - 18;
+
+                               *op++ = 0;
+                               while (tt > 255) {
+                                       tt -= 255;
+                                       *op++ = 0;
+                               }
+                               assert("lzo-05", tt > 0);
+                               *op++ = LZO_BYTE(tt);
+                       }
+                       do
+                               *op++ = *ii++;
+                       while (--t > 0);
+               }
+
+               assert("lzo-06", ii == ip);
+               ip += 3;
+               if (m_pos[3] != *ip++ || m_pos[4] != *ip++ || m_pos[5] != *ip++
+                   || m_pos[6] != *ip++ || m_pos[7] != *ip++
+                   || m_pos[8] != *ip++
+#ifdef LZO1Y
+                   || m_pos[9] != *ip++ || m_pos[10] != *ip++
+                   || m_pos[11] != *ip++ || m_pos[12] != *ip++
+                   || m_pos[13] != *ip++ || m_pos[14] != *ip++
+#endif
+                   ) {
+                       --ip;
+                       m_len = ip - ii;
+                       assert("lzo-07", m_len >= 3);
+                       assert("lzo-08", m_len <= M2_MAX_LEN);
+
+                       if (m_off <= M2_MAX_OFFSET) {
+                               m_off -= 1;
+#if defined(LZO1X)
+                               *op++ =
+                                   LZO_BYTE(((m_len -
+                                              1) << 5) | ((m_off & 7) << 2));
+                               *op++ = LZO_BYTE(m_off >> 3);
+#elif defined(LZO1Y)
+                               *op++ =
+                                   LZO_BYTE(((m_len +
+                                              1) << 4) | ((m_off & 3) << 2));
+                               *op++ = LZO_BYTE(m_off >> 2);
+#endif
+                       } else if (m_off <= M3_MAX_OFFSET) {
+                               m_off -= 1;
+                               *op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
+                               goto m3_m4_offset;
+                       } else
+#if defined(LZO1X)
+                       {
+                               m_off -= 0x4000;
+                               assert("lzo-09", m_off > 0);
+                               assert("lzo-10", m_off <= 0x7fff);
+                               *op++ = LZO_BYTE(M4_MARKER |
+                                                ((m_off & 0x4000) >> 11) |
+                                                (m_len - 2));
+                               goto m3_m4_offset;
+                       }
+#elif defined(LZO1Y)
+                               goto m4_match;
+#endif
+               } else {
+                       {
+                               const lzo_byte *end = in_end;
+                               const lzo_byte *m = m_pos + M2_MAX_LEN + 1;
+                               while (ip < end && *m == *ip)
+                                       m++, ip++;
+                               m_len = (ip - ii);
+                       }
+                       assert("lzo-11", m_len > M2_MAX_LEN);
+
+                       if (m_off <= M3_MAX_OFFSET) {
+                               m_off -= 1;
+                               if (m_len <= 33)
+                                       *op++ =
+                                           LZO_BYTE(M3_MARKER | (m_len - 2));
+                               else {
+                                       m_len -= 33;
+                                       *op++ = M3_MARKER | 0;
+                                       goto m3_m4_len;
+                               }
+                       } else {
+#if defined(LZO1Y)
+                             m4_match:
+#endif
+                               m_off -= 0x4000;
+                               assert("lzo-12", m_off > 0);
+                               assert("lzo-13", m_off <= 0x7fff);
+                               if (m_len <= M4_MAX_LEN)
+                                       *op++ = LZO_BYTE(M4_MARKER |
+                                                        ((m_off & 0x4000) >>
+                                                         11) | (m_len - 2));
+                               else {
+                                       m_len -= M4_MAX_LEN;
+                                       *op++ =
+                                           LZO_BYTE(M4_MARKER |
+                                                    ((m_off & 0x4000) >> 11));
+                                     m3_m4_len:
+                                       while (m_len > 255) {
+                                               m_len -= 255;
+                                               *op++ = 0;
+                                       }
+                                       assert("lzo-14", m_len > 0);
+                                       *op++ = LZO_BYTE(m_len);
+                               }
+                       }
+
+                     m3_m4_offset:
+                       *op++ = LZO_BYTE((m_off & 63) << 2);
+                       *op++ = LZO_BYTE(m_off >> 6);
+               }
+
+               ii = ip;
+               if (ip >= ip_end)
+                       break;
+       }
+
+       *out_len = op - out;
+       return pd(in_end, ii);
+}
+
+int DO_COMPRESS(const lzo_byte * in, lzo_uint in_len,
+               lzo_byte * out, lzo_uintp out_len, lzo_voidp wrkmem)
+{
+       lzo_byte *op = out;
+       lzo_uint t;
+
+#if defined(__LZO_QUERY_COMPRESS)
+       if (__LZO_IS_COMPRESS_QUERY(in, in_len, out, out_len, wrkmem))
+               return __LZO_QUERY_COMPRESS(in, in_len, out, out_len, wrkmem,
+                                           D_SIZE, lzo_sizeof(lzo_dict_t));
+#endif
+
+       if (in_len <= M2_MAX_LEN + 5)
+               t = in_len;
+       else {
+               t = do_compress(in, in_len, op, out_len, wrkmem);
+               op += *out_len;
+       }
+
+       if (t > 0) {
+               const lzo_byte *ii = in + in_len - t;
+
+               if (op == out && t <= 238)
+                       *op++ = LZO_BYTE(17 + t);
+               else if (t <= 3)
+                       op[-2] |= LZO_BYTE(t);
+               else if (t <= 18)
+                       *op++ = LZO_BYTE(t - 3);
+               else {
+                       lzo_uint tt = t - 18;
+
+                       *op++ = 0;
+                       while (tt > 255) {
+                               tt -= 255;
+                               *op++ = 0;
+                       }
+                       assert("lzo-15", tt > 0);
+                       *op++ = LZO_BYTE(tt);
+               }
+               do
+                       *op++ = *ii++;
+               while (--t > 0);
+       }
+
+       *op++ = M4_MARKER | 1;
+       *op++ = 0;
+       *op++ = 0;
+
+       *out_len = op - out;
+       return LZO_E_OK;
+}
+
+#undef do_compress
+#undef DO_COMPRESS
+#undef LZO_HASH
+
+#undef LZO_TEST_DECOMPRESS_OVERRUN
+#undef LZO_TEST_DECOMPRESS_OVERRUN_INPUT
+#undef LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT
+#undef LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND
+#undef DO_DECOMPRESS
+#define DO_DECOMPRESS       lzo1x_decompress
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN)
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_INPUT)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_INPUT       2
+#  endif
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT      2
+#  endif
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND
+#  endif
+#endif
+
+#undef TEST_IP
+#undef TEST_OP
+#undef TEST_LOOKBEHIND
+#undef NEED_IP
+#undef NEED_OP
+#undef HAVE_TEST_IP
+#undef HAVE_TEST_OP
+#undef HAVE_NEED_IP
+#undef HAVE_NEED_OP
+#undef HAVE_ANY_IP
+#undef HAVE_ANY_OP
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_INPUT)
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_INPUT >= 1)
+#    define TEST_IP             (ip < ip_end)
+#  endif
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_INPUT >= 2)
+#    define NEED_IP(x) \
+           if ((lzo_uint)(ip_end - ip) < (lzo_uint)(x))  goto input_overrun
+#  endif
+#endif
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT)
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT >= 1)
+#    define TEST_OP             (op <= op_end)
+#  endif
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT >= 2)
+#    undef TEST_OP
+#    define NEED_OP(x) \
+           if ((lzo_uint)(op_end - op) < (lzo_uint)(x))  goto output_overrun
+#  endif
+#endif
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND)
+#  define TEST_LOOKBEHIND(m_pos,out)    if (m_pos < out) goto lookbehind_overrun
+#else
+#  define TEST_LOOKBEHIND(m_pos,op)     ((void) 0)
+#endif
+
+#if !defined(LZO_EOF_CODE) && !defined(TEST_IP)
+#  define TEST_IP               (ip < ip_end)
+#endif
+
+#if defined(TEST_IP)
+#  define HAVE_TEST_IP
+#else
+#  define TEST_IP               1
+#endif
+#if defined(TEST_OP)
+#  define HAVE_TEST_OP
+#else
+#  define TEST_OP               1
+#endif
+
+#if defined(NEED_IP)
+#  define HAVE_NEED_IP
+#else
+#  define NEED_IP(x)            ((void) 0)
+#endif
+#if defined(NEED_OP)
+#  define HAVE_NEED_OP
+#else
+#  define NEED_OP(x)            ((void) 0)
+#endif
+
+#if defined(HAVE_TEST_IP) || defined(HAVE_NEED_IP)
+#  define HAVE_ANY_IP
+#endif
+#if defined(HAVE_TEST_OP) || defined(HAVE_NEED_OP)
+#  define HAVE_ANY_OP
+#endif
+
+#undef __COPY4
+#define __COPY4(dst,src)    * (lzo_uint32p)(dst) = * (const lzo_uint32p)(src)
+
+#undef COPY4
+#if defined(LZO_UNALIGNED_OK_4)
+#  define COPY4(dst,src)    __COPY4(dst,src)
+#elif defined(LZO_ALIGNED_OK_4)
+#  define COPY4(dst,src)    __COPY4((lzo_ptr_t)(dst),(lzo_ptr_t)(src))
+#endif
+
+#if defined(DO_DECOMPRESS)
+int DO_DECOMPRESS(const lzo_byte * in, lzo_uint in_len,
+                 lzo_byte * out, lzo_uintp out_len, lzo_voidp wrkmem)
+#endif
+{
+       register lzo_byte *op;
+       register const lzo_byte *ip;
+       register lzo_uint t;
+#if defined(COPY_DICT)
+       lzo_uint m_off;
+       const lzo_byte *dict_end;
+#else
+       register const lzo_byte *m_pos;
+#endif
+
+       const lzo_byte *const ip_end = in + in_len;
+#if defined(HAVE_ANY_OP)
+       lzo_byte *const op_end = out + *out_len;
+#endif
+#if defined(LZO1Z)
+       lzo_uint last_m_off = 0;
+#endif
+
+       LZO_UNUSED(wrkmem);
+
+#if defined(__LZO_QUERY_DECOMPRESS)
+       if (__LZO_IS_DECOMPRESS_QUERY(in, in_len, out, out_len, wrkmem))
+               return __LZO_QUERY_DECOMPRESS(in, in_len, out, out_len, wrkmem,
+                                             0, 0);
+#endif
+
+#if defined(COPY_DICT)
+       if (dict) {
+               if (dict_len > M4_MAX_OFFSET) {
+                       dict += dict_len - M4_MAX_OFFSET;
+                       dict_len = M4_MAX_OFFSET;
+               }
+               dict_end = dict + dict_len;
+       } else {
+               dict_len = 0;
+               dict_end = NULL;
+       }
+#endif
+
+       *out_len = 0;
+
+       op = out;
+       ip = in;
+
+       if (*ip > 17) {
+               t = *ip++ - 17;
+               if (t < 4)
+                       goto match_next;
+               assert("lzo-16", t > 0);
+               NEED_OP(t);
+               NEED_IP(t + 1);
+               do
+                       *op++ = *ip++;
+               while (--t > 0);
+               goto first_literal_run;
+       }
+
+       while (TEST_IP && TEST_OP) {
+               t = *ip++;
+               if (t >= 16)
+                       goto match;
+               if (t == 0) {
+                       NEED_IP(1);
+                       while (*ip == 0) {
+                               t += 255;
+                               ip++;
+                               NEED_IP(1);
+                       }
+                       t += 15 + *ip++;
+               }
+               assert("lzo-17", t > 0);
+               NEED_OP(t + 3);
+               NEED_IP(t + 4);
+#if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
+#if !defined(LZO_UNALIGNED_OK_4)
+               if (PTR_ALIGNED2_4(op, ip)) {
+#endif
+                       COPY4(op, ip);
+                       op += 4;
+                       ip += 4;
+                       if (--t > 0) {
+                               if (t >= 4) {
+                                       do {
+                                               COPY4(op, ip);
+                                               op += 4;
+                                               ip += 4;
+                                               t -= 4;
+                                       } while (t >= 4);
+                                       if (t > 0)
+                                               do
+                                                       *op++ = *ip++;
+                                               while (--t > 0);
+                               } else
+                                       do
+                                               *op++ = *ip++;
+                                       while (--t > 0);
+                       }
+#if !defined(LZO_UNALIGNED_OK_4)
+               } else
+#endif
+#endif
+#if !defined(LZO_UNALIGNED_OK_4)
+               {
+                       *op++ = *ip++;
+                       *op++ = *ip++;
+                       *op++ = *ip++;
+                       do
+                               *op++ = *ip++;
+                       while (--t > 0);
+               }
+#endif
+
+             first_literal_run:
+
+               t = *ip++;
+               if (t >= 16)
+                       goto match;
+#if defined(COPY_DICT)
+#if defined(LZO1Z)
+               m_off = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
+               last_m_off = m_off;
+#else
+               m_off = (1 + M2_MAX_OFFSET) + (t >> 2) + (*ip++ << 2);
+#endif
+               NEED_OP(3);
+               t = 3;
+               COPY_DICT(t, m_off)
+#else
+#if defined(LZO1Z)
+               t = (1 + M2_MAX_OFFSET) + (t << 6) + (*ip++ >> 2);
+               m_pos = op - t;
+               last_m_off = t;
+#else
+               m_pos = op - (1 + M2_MAX_OFFSET);
+               m_pos -= t >> 2;
+               m_pos -= *ip++ << 2;
+#endif
+               TEST_LOOKBEHIND(m_pos, out);
+               NEED_OP(3);
+               *op++ = *m_pos++;
+               *op++ = *m_pos++;
+               *op++ = *m_pos;
+#endif
+               goto match_done;
+
+               while (TEST_IP && TEST_OP) {
+                     match:
+                       if (t >= 64) {
+#if defined(COPY_DICT)
+#if defined(LZO1X)
+                               m_off = 1 + ((t >> 2) & 7) + (*ip++ << 3);
+                               t = (t >> 5) - 1;
+#elif defined(LZO1Y)
+                               m_off = 1 + ((t >> 2) & 3) + (*ip++ << 2);
+                               t = (t >> 4) - 3;
+#elif defined(LZO1Z)
+                               m_off = t & 0x1f;
+                               if (m_off >= 0x1c)
+                                       m_off = last_m_off;
+                               else {
+                                       m_off = 1 + (m_off << 6) + (*ip++ >> 2);
+                                       last_m_off = m_off;
+                               }
+                               t = (t >> 5) - 1;
+#endif
+#else
+#if defined(LZO1X)
+                               m_pos = op - 1;
+                               m_pos -= (t >> 2) & 7;
+                               m_pos -= *ip++ << 3;
+                               t = (t >> 5) - 1;
+#elif defined(LZO1Y)
+                               m_pos = op - 1;
+                               m_pos -= (t >> 2) & 3;
+                               m_pos -= *ip++ << 2;
+                               t = (t >> 4) - 3;
+#elif defined(LZO1Z)
+                               {
+                                       lzo_uint off = t & 0x1f;
+                                       m_pos = op;
+                                       if (off >= 0x1c) {
+                                               assert(last_m_off > 0);
+                                               m_pos -= last_m_off;
+                                       } else {
+                                               off =
+                                                   1 + (off << 6) +
+                                                   (*ip++ >> 2);
+                                               m_pos -= off;
+                                               last_m_off = off;
+                                       }
+                               }
+                               t = (t >> 5) - 1;
+#endif
+                               TEST_LOOKBEHIND(m_pos, out);
+                               assert("lzo-18", t > 0);
+                               NEED_OP(t + 3 - 1);
+                               goto copy_match;
+#endif
+                       } else if (t >= 32) {
+                               t &= 31;
+                               if (t == 0) {
+                                       NEED_IP(1);
+                                       while (*ip == 0) {
+                                               t += 255;
+                                               ip++;
+                                               NEED_IP(1);
+                                       }
+                                       t += 31 + *ip++;
+                               }
+#if defined(COPY_DICT)
+#if defined(LZO1Z)
+                               m_off = 1 + (ip[0] << 6) + (ip[1] >> 2);
+                               last_m_off = m_off;
+#else
+                               m_off = 1 + (ip[0] >> 2) + (ip[1] << 6);
+#endif
+#else
+#if defined(LZO1Z)
+                               {
+                                       lzo_uint off =
+                                           1 + (ip[0] << 6) + (ip[1] >> 2);
+                                       m_pos = op - off;
+                                       last_m_off = off;
+                               }
+#elif defined(LZO_UNALIGNED_OK_2) && (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
+                               m_pos = op - 1;
+                               m_pos -= (*(const lzo_ushortp)ip) >> 2;
+#else
+                               m_pos = op - 1;
+                               m_pos -= (ip[0] >> 2) + (ip[1] << 6);
+#endif
+#endif
+                               ip += 2;
+                       } else if (t >= 16) {
+#if defined(COPY_DICT)
+                               m_off = (t & 8) << 11;
+#else
+                               m_pos = op;
+                               m_pos -= (t & 8) << 11;
+#endif
+                               t &= 7;
+                               if (t == 0) {
+                                       NEED_IP(1);
+                                       while (*ip == 0) {
+                                               t += 255;
+                                               ip++;
+                                               NEED_IP(1);
+                                       }
+                                       t += 7 + *ip++;
+                               }
+#if defined(COPY_DICT)
+#if defined(LZO1Z)
+                               m_off += (ip[0] << 6) + (ip[1] >> 2);
+#else
+                               m_off += (ip[0] >> 2) + (ip[1] << 6);
+#endif
+                               ip += 2;
+                               if (m_off == 0)
+                                       goto eof_found;
+                               m_off += 0x4000;
+#if defined(LZO1Z)
+                               last_m_off = m_off;
+#endif
+#else
+#if defined(LZO1Z)
+                               m_pos -= (ip[0] << 6) + (ip[1] >> 2);
+#elif defined(LZO_UNALIGNED_OK_2) && (LZO_BYTE_ORDER == LZO_LITTLE_ENDIAN)
+                               m_pos -= (*(const lzo_ushortp)ip) >> 2;
+#else
+                               m_pos -= (ip[0] >> 2) + (ip[1] << 6);
+#endif
+                               ip += 2;
+                               if (m_pos == op)
+                                       goto eof_found;
+                               m_pos -= 0x4000;
+#if defined(LZO1Z)
+                               last_m_off = op - m_pos;
+#endif
+#endif
+                       } else {
+#if defined(COPY_DICT)
+#if defined(LZO1Z)
+                               m_off = 1 + (t << 6) + (*ip++ >> 2);
+                               last_m_off = m_off;
+#else
+                               m_off = 1 + (t >> 2) + (*ip++ << 2);
+#endif
+                               NEED_OP(2);
+                               t = 2;
+                               COPY_DICT(t, m_off)
+#else
+#if defined(LZO1Z)
+                               t = 1 + (t << 6) + (*ip++ >> 2);
+                               m_pos = op - t;
+                               last_m_off = t;
+#else
+                               m_pos = op - 1;
+                               m_pos -= t >> 2;
+                               m_pos -= *ip++ << 2;
+#endif
+                               TEST_LOOKBEHIND(m_pos, out);
+                               NEED_OP(2);
+                               *op++ = *m_pos++;
+                               *op++ = *m_pos;
+#endif
+                               goto match_done;
+                       }
+
+#if defined(COPY_DICT)
+
+                       NEED_OP(t + 3 - 1);
+                       t += 3 - 1;
+                       COPY_DICT(t, m_off)
+#else
+
+                       TEST_LOOKBEHIND(m_pos, out);
+                       assert("lzo-19", t > 0);
+                       NEED_OP(t + 3 - 1);
+#if defined(LZO_UNALIGNED_OK_4) || defined(LZO_ALIGNED_OK_4)
+#if !defined(LZO_UNALIGNED_OK_4)
+                       if (t >= 2 * 4 - (3 - 1) && PTR_ALIGNED2_4(op, m_pos)) {
+                               assert((op - m_pos) >= 4);
+#else
+                       if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) {
+#endif
+                               COPY4(op, m_pos);
+                               op += 4;
+                               m_pos += 4;
+                               t -= 4 - (3 - 1);
+                               do {
+                                       COPY4(op, m_pos);
+                                       op += 4;
+                                       m_pos += 4;
+                                       t -= 4;
+                               } while (t >= 4);
+                               if (t > 0)
+                                       do
+                                               *op++ = *m_pos++;
+                                       while (--t > 0);
+                       } else
+#endif
+                       {
+                             copy_match:
+                               *op++ = *m_pos++;
+                               *op++ = *m_pos++;
+                               do
+                                       *op++ = *m_pos++;
+                               while (--t > 0);
+                       }
+
+#endif
+
+                     match_done:
+#if defined(LZO1Z)
+                       t = ip[-1] & 3;
+#else
+                       t = ip[-2] & 3;
+#endif
+                       if (t == 0)
+                               break;
+
+                     match_next:
+                       assert("lzo-20", t > 0);
+                       NEED_OP(t);
+                       NEED_IP(t + 1);
+                       do
+                               *op++ = *ip++;
+                       while (--t > 0);
+                       t = *ip++;
+               }
+       }
+
+#if defined(HAVE_TEST_IP) || defined(HAVE_TEST_OP)
+       *out_len = op - out;
+       return LZO_E_EOF_NOT_FOUND;
+#endif
+
+      eof_found:
+       assert("lzo-21", t == 1);
+       *out_len = op - out;
+       return (ip == ip_end ? LZO_E_OK :
+               (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
+
+#if defined(HAVE_NEED_IP)
+      input_overrun:
+       *out_len = op - out;
+       return LZO_E_INPUT_OVERRUN;
+#endif
+
+#if defined(HAVE_NEED_OP)
+      output_overrun:
+       *out_len = op - out;
+       return LZO_E_OUTPUT_OVERRUN;
+#endif
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND)
+      lookbehind_overrun:
+       *out_len = op - out;
+       return LZO_E_LOOKBEHIND_OVERRUN;
+#endif
+}
+
+#define LZO_TEST_DECOMPRESS_OVERRUN
+#undef DO_DECOMPRESS
+#define DO_DECOMPRESS       lzo1x_decompress_safe
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN)
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_INPUT)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_INPUT       2
+#  endif
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT      2
+#  endif
+#  if !defined(LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND)
+#    define LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND
+#  endif
+#endif
+
+#undef TEST_IP
+#undef TEST_OP
+#undef TEST_LOOKBEHIND
+#undef NEED_IP
+#undef NEED_OP
+#undef HAVE_TEST_IP
+#undef HAVE_TEST_OP
+#undef HAVE_NEED_IP
+#undef HAVE_NEED_OP
+#undef HAVE_ANY_IP
+#undef HAVE_ANY_OP
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_INPUT)
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_INPUT >= 1)
+#    define TEST_IP             (ip < ip_end)
+#  endif
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_INPUT >= 2)
+#    define NEED_IP(x) \
+           if ((lzo_uint)(ip_end - ip) < (lzo_uint)(x))  goto input_overrun
+#  endif
+#endif
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT)
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT >= 1)
+#    define TEST_OP             (op <= op_end)
+#  endif
+#  if (LZO_TEST_DECOMPRESS_OVERRUN_OUTPUT >= 2)
+#    undef TEST_OP
+#    define NEED_OP(x) \
+           if ((lzo_uint)(op_end - op) < (lzo_uint)(x))  goto output_overrun
+#  endif
+#endif
+
+#if defined(LZO_TEST_DECOMPRESS_OVERRUN_LOOKBEHIND)
+#  define TEST_LOOKBEHIND(m_pos,out)    if (m_pos < out) goto lookbehind_overrun
+#else
+#  define TEST_LOOKBEHIND(m_pos,op)     ((void) 0)
+#endif
+
+#if !defined(LZO_EOF_CODE) && !defined(TEST_IP)
+#  define TEST_IP               (ip < ip_end)
+#endif
+
+#if defined(TEST_IP)
+#  define HAVE_TEST_IP
+#else
+#  define TEST_IP               1
+#endif
+#if defined(TEST_OP)
+#  define HAVE_TEST_OP
+#else
+#  define TEST_OP               1
+#endif
+
+#if defined(NEED_IP)
+#  define HAVE_NEED_IP
+#else
+#  define NEED_IP(x)            ((void) 0)
+#endif
+#if defined(NEED_OP)
+#  define HAVE_NEED_OP
+#else
+#  define NEED_OP(x)            ((void) 0)
+#endif
+
+#if defined(HAVE_TEST_IP) || defined(HAVE_NEED_IP)
+#  define HAVE_ANY_IP
+#endif
+#if defined(HAVE_TEST_OP) || defined(HAVE_NEED_OP)
+#  define HAVE_ANY_OP
+#endif
+
+#undef __COPY4
+#define __COPY4(dst,src)    * (lzo_uint32p)(dst) = * (const lzo_uint32p)(src)
+
+#undef COPY4
+#if defined(LZO_UNALIGNED_OK_4)
+#  define COPY4(dst,src)    __COPY4(dst,src)
+#elif defined(LZO_ALIGNED_OK_4)
+#  define COPY4(dst,src)    __COPY4((lzo_ptr_t)(dst),(lzo_ptr_t)(src))
+#endif
+
+/***** End of minilzo.c *****/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/compress/minilzo.h linux-2.6.20/fs/reiser4/plugin/compress/minilzo.h
--- linux-2.6.20.orig/fs/reiser4/plugin/compress/minilzo.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/compress/minilzo.h   2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,70 @@
+/* minilzo.h -- mini subset of the LZO real-time data compression library
+   adopted for reiser4 compression transform plugin.
+
+   This file is part of the LZO real-time data compression library
+   and not included in any proprietary licenses of reiser4.
+
+   Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+   Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
+   All Rights Reserved.
+
+   The LZO library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU General Public License as
+   published by the Free Software Foundation; either version 2 of
+   the License, or (at your option) any later version.
+
+   The LZO library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with the LZO library; see the file COPYING.
+   If not, write to the Free Software Foundation, Inc.,
+   59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+
+   Markus F.X.J. Oberhumer
+   <markus@oberhumer.com>
+   http://www.oberhumer.com/opensource/lzo/
+ */
+
+/*
+ * NOTE:
+ *   the full LZO package can be found at
+ *   http://www.oberhumer.com/opensource/lzo/
+ */
+
+#ifndef __MINILZO_H
+#define __MINILZO_H
+
+#define MINILZO_VERSION         0x1080
+
+#include "lzoconf.h"
+
+/* Memory required for the wrkmem parameter.
+ * When the required size is 0, you can also pass a NULL pointer.
+ */
+
+#define LZO1X_MEM_COMPRESS      LZO1X_1_MEM_COMPRESS
+#define LZO1X_1_MEM_COMPRESS    ((lzo_uint32) (16384L * lzo_sizeof_dict_t))
+#define LZO1X_MEM_DECOMPRESS    (0)
+
+/* compression */
+extern int lzo1x_1_compress(const lzo_byte * src, lzo_uint src_len,
+                           lzo_byte * dst, lzo_uintp dst_len,
+                           lzo_voidp wrkmem);
+/* decompression */
+extern int lzo1x_decompress(const lzo_byte * src, lzo_uint src_len,
+                           lzo_byte * dst, lzo_uintp dst_len,
+                           lzo_voidp wrkmem /* NOT USED */);
+/* safe decompression with overrun testing */
+extern int lzo1x_decompress_safe(const lzo_byte * src, lzo_uint src_len,
+                                lzo_byte * dst, lzo_uintp dst_len,
+                                lzo_voidp wrkmem /* NOT USED */ );
+
+#endif                         /* already included */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/crypto/cipher.c linux-2.6.20/fs/reiser4/plugin/crypto/cipher.c
--- linux-2.6.20.orig/fs/reiser4/plugin/crypto/cipher.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/crypto/cipher.c      2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,37 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser,
+   licensing governed by reiser4/README */
+/* Reiser4 cipher transform plugins */
+
+#include "../../debug.h"
+#include "../plugin.h"
+
+cipher_plugin cipher_plugins[LAST_CIPHER_ID] = {
+       [NONE_CIPHER_ID] = {
+               .h = {
+                       .type_id = REISER4_CIPHER_PLUGIN_TYPE,
+                       .id = NONE_CIPHER_ID,
+                       .pops = NULL,
+                       .label = "none",
+                       .desc = "no cipher transform",
+                       .linkage = {NULL, NULL}
+               },
+               .alloc = NULL,
+               .free = NULL,
+               .scale = NULL,
+               .align_stream = NULL,
+               .setkey = NULL,
+               .encrypt = NULL,
+               .decrypt = NULL
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/crypto/cipher.h linux-2.6.20/fs/reiser4/plugin/crypto/cipher.h
--- linux-2.6.20.orig/fs/reiser4/plugin/crypto/cipher.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/crypto/cipher.h      2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,55 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* This file contains definitions for the objects operated
+   by reiser4 key manager, which is something like keyring
+   wrapped by appropriate reiser4 plugin */
+
+#if !defined( __FS_REISER4_CRYPT_H__ )
+#define __FS_REISER4_CRYPT_H__
+
+#include <linux/crypto.h>
+
+/* key info imported from user space */
+typedef struct crypto_data {
+       int keysize;    /* uninstantiated key size */
+       __u8 * key;     /* uninstantiated key */
+       int keyid_size; /* size of passphrase */
+       __u8 * keyid;   /* passphrase */
+} crypto_data_t;
+
+/* This object contains all needed infrastructure to implement
+   cipher transform. This is operated (allocating, inheriting,
+   validating, binding to host inode, etc..) by reiser4 key manager.
+
+   This info can be allocated in two cases:
+   1. importing a key from user space.
+   2. reading inode from disk */
+typedef struct crypto_stat {
+       struct inode * host;
+       struct crypto_hash      * digest;
+       struct crypto_blkcipher * cipher;
+#if 0
+       cipher_key_plugin * kplug; /* key manager */
+#endif
+       __u8 * keyid;              /* key fingerprint, created by digest plugin,
+                                     using uninstantiated key and passphrase.
+                                     supposed to be stored in disk stat-data */
+       int inst;                  /* this indicates if the cipher key is
+                                     instantiated (case 1 above) */
+       int keysize;               /* uninstantiated key size (bytes), supposed
+                                     to be stored in disk stat-data */
+       int keyload_count;         /* number of the objects which has this
+                                     crypto-stat attached */
+} crypto_stat_t;
+
+#endif /* __FS_REISER4_CRYPT_H__ */
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/crypto/digest.c linux-2.6.20/fs/reiser4/plugin/crypto/digest.c
--- linux-2.6.20.orig/fs/reiser4/plugin/crypto/digest.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/crypto/digest.c      2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,58 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* reiser4 digest transform plugin (is used by cryptcompress object plugin) */
+/* EDWARD-FIXME-HANS: and it does what? a digest is a what? */
+#include "../../debug.h"
+#include "../plugin_header.h"
+#include "../plugin.h"
+#include "../file/cryptcompress.h"
+
+#include <linux/types.h>
+
+extern digest_plugin digest_plugins[LAST_DIGEST_ID];
+
+static struct crypto_hash * alloc_sha256 (void)
+{
+#if REISER4_SHA256
+       return crypto_alloc_hash ("sha256", 0, CRYPTO_ALG_ASYNC);
+#else
+       warning("edward-1418", "sha256 unsupported");
+       return ERR_PTR(-EINVAL);
+#endif
+}
+
+static void free_sha256 (struct crypto_hash * tfm)
+{
+#if REISER4_SHA256
+       crypto_free_hash(tfm);
+#endif
+       return;
+}
+
+/* digest plugins */
+digest_plugin digest_plugins[LAST_DIGEST_ID] = {
+       [SHA256_32_DIGEST_ID] = {
+               .h = {
+                       .type_id = REISER4_DIGEST_PLUGIN_TYPE,
+                       .id = SHA256_32_DIGEST_ID,
+                       .pops = NULL,
+                       .label = "sha256_32",
+                       .desc = "sha256_32 digest transform",
+                       .linkage = {NULL, NULL}
+               },
+               .fipsize = sizeof(__u32),
+               .alloc = alloc_sha256,
+               .free = free_sha256
+       }
+};
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 120
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/dir/dir.h linux-2.6.20/fs/reiser4/plugin/dir/dir.h
--- linux-2.6.20.orig/fs/reiser4/plugin/dir/dir.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/dir/dir.h    2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,36 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* this file contains declarations of methods implementing directory plugins */
+
+#if !defined( __REISER4_DIR_H__ )
+#define __REISER4_DIR_H__
+
+/*#include "../../key.h"
+
+#include <linux/fs.h>*/
+
+/* declarations of functions implementing HASHED_DIR_PLUGIN_ID dir plugin */
+
+/* "hashed" directory methods of dir plugin */
+void build_entry_key_hashed(const struct inode *, const struct qstr *,
+                           reiser4_key *);
+
+/* declarations of functions implementing SEEKABLE_HASHED_DIR_PLUGIN_ID dir plugin */
+
+/* "seekable" directory methods of dir plugin */
+void build_entry_key_seekable(const struct inode *, const struct qstr *,
+                             reiser4_key *);
+
+/* __REISER4_DIR_H__ */
+#endif
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/dir/hashed_dir.c linux-2.6.20/fs/reiser4/plugin/dir/hashed_dir.c
--- linux-2.6.20.orig/fs/reiser4/plugin/dir/hashed_dir.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/dir/hashed_dir.c     2007-05-06 14:50:43.754993222 +0400
@@ -0,0 +1,81 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Directory plugin using hashes (see fs/reiser4/plugin/hash.c) to map file
+   names to the files. */
+
+/*
+ * Hashed directory logically consists of persistent directory
+ * entries. Directory entry is a pair of a file name and a key of stat-data of
+ * a file that has this name in the given directory.
+ *
+ * Directory entries are stored in the tree in the form of directory
+ * items. Directory item should implement dir_entry_ops portion of item plugin
+ * interface (see plugin/item/item.h). Hashed directory interacts with
+ * directory item plugin exclusively through dir_entry_ops operations.
+ *
+ * Currently there are two implementations of directory items: "simple
+ * directory item" (plugin/item/sde.[ch]), and "compound directory item"
+ * (plugin/item/cde.[ch]) with the latter being the default.
+ *
+ * There is, however some delicate way through which directory code interferes
+ * with item plugin: key assignment policy. A key for a directory item is
+ * chosen by directory code, and as described in kassign.c, this key contains
+ * a portion of file name. Directory item uses this knowledge to avoid storing
+ * this portion of file name twice: in the key and in the directory item body.
+ *
+ */
+
+#include "../../inode.h"
+
+void complete_entry_key(const struct inode *, const char *name,
+                       int len, reiser4_key * result);
+
+/* this is implementation of build_entry_key method of dir
+   plugin for HASHED_DIR_PLUGIN_ID
+ */
+void build_entry_key_hashed(const struct inode *dir,   /* directory where entry is
+                                                        * (or will be) in.*/
+                           const struct qstr *qname,   /* name of file referenced
+                                                        * by this entry */
+                           reiser4_key * result        /* resulting key of directory
+                                                        * entry */ )
+{
+       const char *name;
+       int len;
+
+       assert("nikita-1139", dir != NULL);
+       assert("nikita-1140", qname != NULL);
+       assert("nikita-1141", qname->name != NULL);
+       assert("nikita-1142", result != NULL);
+
+       name = qname->name;
+       len = qname->len;
+
+       assert("nikita-2867", strlen(name) == len);
+
+       reiser4_key_init(result);
+       /* locality of directory entry's key is objectid of parent
+          directory */
+       set_key_locality(result, get_inode_oid(dir));
+       /* minor packing locality is constant */
+       set_key_type(result, KEY_FILE_NAME_MINOR);
+       /* dot is special case---we always want it to be first entry in
+          a directory. Actually, we just want to have smallest
+          directory entry.
+        */
+       if (len == 1 && name[0] == '.')
+               return;
+
+       /* initialize part of entry key which depends on file name */
+       complete_entry_key(dir, name, len, result);
+}
+
+/* Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/dir/Makefile linux-2.6.20/fs/reiser4/plugin/dir/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/dir/Makefile    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/dir/Makefile 2007-05-06 14:50:43.758994472 +0400
@@ -0,0 +1,5 @@
+obj-$(CONFIG_REISER4_FS) += dir_plugins.o
+
+dir_plugins-objs :=    \
+       hashed_dir.o    \
+       seekable_dir.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/dir/seekable_dir.c linux-2.6.20/fs/reiser4/plugin/dir/seekable_dir.c
--- linux-2.6.20.orig/fs/reiser4/plugin/dir/seekable_dir.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/dir/seekable_dir.c   2007-05-06 14:50:43.758994472 +0400
@@ -0,0 +1,46 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "../../inode.h"
+
+/* this is implementation of build_entry_key method of dir
+   plugin for SEEKABLE_HASHED_DIR_PLUGIN_ID
+   This is for directories where we want repeatable and restartable readdir()
+   even in case 32bit user level struct dirent (readdir(3)).
+*/
+void
+build_entry_key_seekable(const struct inode *dir, const struct qstr *name,
+                        reiser4_key * result)
+{
+       oid_t objectid;
+
+       assert("nikita-2283", dir != NULL);
+       assert("nikita-2284", name != NULL);
+       assert("nikita-2285", name->name != NULL);
+       assert("nikita-2286", result != NULL);
+
+       reiser4_key_init(result);
+       /* locality of directory entry's key is objectid of parent
+          directory */
+       set_key_locality(result, get_inode_oid(dir));
+       /* minor packing locality is constant */
+       set_key_type(result, KEY_FILE_NAME_MINOR);
+       /* dot is special case---we always want it to be first entry in
+          a directory. Actually, we just want to have smallest
+          directory entry.
+        */
+       if ((name->len == 1) && (name->name[0] == '.'))
+               return;
+
+       /* objectid of key is 31 lowest bits of hash. */
+       objectid =
+           inode_hash_plugin(dir)->hash(name->name,
+                                        (int)name->len) & 0x7fffffff;
+
+       assert("nikita-2303", !(objectid & ~KEY_OBJECTID_MASK));
+       set_key_objectid(result, objectid);
+
+       /* offset is always 0. */
+       set_key_offset(result, (__u64) 0);
+       return;
+}
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/dir_plugin_common.c linux-2.6.20/fs/reiser4/plugin/dir_plugin_common.c
--- linux-2.6.20.orig/fs/reiser4/plugin/dir_plugin_common.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/dir_plugin_common.c  2007-05-06 14:50:43.758994472 +0400
@@ -0,0 +1,872 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+   reiser4/README */
+
+/* this file contains typical implementations for most of methods of
+   directory plugin
+*/
+
+#include "../inode.h"
+
+int reiser4_find_entry(struct inode *dir, struct dentry *name,
+              lock_handle *, znode_lock_mode, reiser4_dir_entry_desc *);
+int reiser4_lookup_name(struct inode *parent, struct dentry *dentry, reiser4_key * key);
+void check_light_weight(struct inode *inode, struct inode *parent);
+
+/* this is common implementation of get_parent method of dir plugin
+   this is used by NFS kernel server to "climb" up directory tree to
+   check permissions
+ */
+struct dentry *get_parent_common(struct inode *child)
+{
+       struct super_block *s;
+       struct inode *parent;
+       struct dentry dotdot;
+       struct dentry *dentry;
+       reiser4_key key;
+       int result;
+
+       /*
+        * lookup dotdot entry.
+        */
+
+       s = child->i_sb;
+       memset(&dotdot, 0, sizeof(dotdot));
+       dotdot.d_name.name = "..";
+       dotdot.d_name.len = 2;
+       dotdot.d_op = &get_super_private(s)->ops.dentry;
+
+       result = reiser4_lookup_name(child, &dotdot, &key);
+       if (result != 0)
+               return ERR_PTR(result);
+
+       parent = reiser4_iget(s, &key, 1);
+       if (!IS_ERR(parent)) {
+               /*
+                * FIXME-NIKITA dubious: attributes are inherited from @child
+                * to @parent. But:
+                *
+                *     (*) this is the only this we can do
+                *
+                *     (*) attributes of light-weight object are inherited
+                *     from a parent through which object was looked up first,
+                *     so it is ambiguous anyway.
+                *
+                */
+               check_light_weight(parent, child);
+               reiser4_iget_complete(parent);
+               dentry = d_alloc_anon(parent);
+               if (dentry == NULL) {
+                       iput(parent);
+                       dentry = ERR_PTR(RETERR(-ENOMEM));
+               } else
+                       dentry->d_op = &get_super_private(s)->ops.dentry;
+       } else if (PTR_ERR(parent) == -ENOENT)
+               dentry = ERR_PTR(RETERR(-ESTALE));
+       else
+               dentry = (void *)parent;
+       return dentry;
+}
+
+/* this is common implementation of is_name_acceptable method of dir
+   plugin
+ */
+int is_name_acceptable_common(const struct inode *inode,       /* directory to check */
+                             const char *name UNUSED_ARG,      /* name to check */
+                             int len /* @name's length */ )
+{
+       assert("nikita-733", inode != NULL);
+       assert("nikita-734", name != NULL);
+       assert("nikita-735", len > 0);
+
+       return len <= reiser4_max_filename_len(inode);
+}
+
+/* there is no common implementation of build_entry_key method of dir
+   plugin. See plugin/dir/hashed_dir.c:build_entry_key_hashed() or
+   plugin/dir/seekable.c:build_entry_key_seekable() for example
+*/
+
+/* this is common implementation of build_readdir_key method of dir
+   plugin
+   see reiser4_readdir_common for more details
+*/
+int build_readdir_key_common(struct file *dir /* directory being read */ ,
+                            reiser4_key * result /* where to store key */ )
+{
+       reiser4_file_fsdata *fdata;
+       struct inode *inode;
+
+       assert("nikita-1361", dir != NULL);
+       assert("nikita-1362", result != NULL);
+       assert("nikita-1363", dir->f_dentry != NULL);
+       inode = dir->f_dentry->d_inode;
+       assert("nikita-1373", inode != NULL);
+
+       fdata = reiser4_get_file_fsdata(dir);
+       if (IS_ERR(fdata))
+               return PTR_ERR(fdata);
+       assert("nikita-1364", fdata != NULL);
+       return extract_key_from_de_id(get_inode_oid(inode),
+                                     &fdata->dir.readdir.position.
+                                     dir_entry_key, result);
+
+}
+
+void reiser4_adjust_dir_file(struct inode *, const struct dentry *, int offset,
+                            int adj);
+
+/* this is common implementation of add_entry method of dir plugin
+*/
+int reiser4_add_entry_common(struct inode *object, /* directory to add new name
+                                                   * in */
+                            struct dentry *where,      /* new name */
+                            reiser4_object_create_data * data, /* parameters of
+                                                               *  new object */
+                            reiser4_dir_entry_desc * entry /* parameters of
+                                                            * new directory
+                                                            * entry */)
+{
+       int result;
+       coord_t *coord;
+       lock_handle lh;
+       reiser4_dentry_fsdata *fsdata;
+       reiser4_block_nr reserve;
+
+       assert("nikita-1114", object != NULL);
+       assert("nikita-1250", where != NULL);
+
+       fsdata = reiser4_get_dentry_fsdata(where);
+       if (unlikely(IS_ERR(fsdata)))
+               return PTR_ERR(fsdata);
+
+       reserve = inode_dir_plugin(object)->estimate.add_entry(object);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT))
+               return RETERR(-ENOSPC);
+
+       init_lh(&lh);
+       coord = &fsdata->dec.entry_coord;
+       coord_clear_iplug(coord);
+
+       /* check for this entry in a directory. This is plugin method. */
+       result = reiser4_find_entry(object, where, &lh, ZNODE_WRITE_LOCK,
+                                   entry);
+       if (likely(result == -ENOENT)) {
+               /* add new entry. Just pass control to the directory
+                  item plugin. */
+               assert("nikita-1709", inode_dir_item_plugin(object));
+               assert("nikita-2230", coord->node == lh.node);
+               reiser4_seal_done(&fsdata->dec.entry_seal);
+               result =
+                   inode_dir_item_plugin(object)->s.dir.add_entry(object,
+                                                                  coord, &lh,
+                                                                  where,
+                                                                  entry);
+               if (result == 0) {
+                       reiser4_adjust_dir_file(object, where,
+                                               fsdata->dec.pos + 1, +1);
+                       INODE_INC_FIELD(object, i_size);
+               }
+       } else if (result == 0) {
+               assert("nikita-2232", coord->node == lh.node);
+               result = RETERR(-EEXIST);
+       }
+       done_lh(&lh);
+
+       return result;
+}
+
+/**
+ * rem_entry - remove entry from directory item
+ * @dir:
+ * @dentry:
+ * @entry:
+ * @coord:
+ * @lh:
+ *
+ * Checks that coordinate @coord is set properly and calls item plugin
+ * method to cut entry.
+ */
+static int
+rem_entry(struct inode *dir, struct dentry *dentry,
+         reiser4_dir_entry_desc * entry, coord_t * coord, lock_handle * lh)
+{
+       item_plugin *iplug;
+       struct inode *child;
+
+       iplug = inode_dir_item_plugin(dir);
+       child = dentry->d_inode;
+       assert("nikita-3399", child != NULL);
+
+       /* check that we are really destroying an entry for @child */
+       if (REISER4_DEBUG) {
+               int result;
+               reiser4_key key;
+
+               result = iplug->s.dir.extract_key(coord, &key);
+               if (result != 0)
+                       return result;
+               if (get_key_objectid(&key) != get_inode_oid(child)) {
+                       warning("nikita-3397",
+                               "rem_entry: %#llx != %#llx\n",
+                               get_key_objectid(&key),
+                               (unsigned long long)get_inode_oid(child));
+                       return RETERR(-EIO);
+               }
+       }
+       return iplug->s.dir.rem_entry(dir, &dentry->d_name, coord, lh, entry);
+}
+
+/**
+ * reiser4_rem_entry_common - remove entry from a directory
+ * @dir: directory to remove entry from
+ * @where: name that is being removed
+ * @entry: description of entry being removed
+ *
+ * This is common implementation of rem_entry method of dir plugin.
+ */
+int reiser4_rem_entry_common(struct inode *dir,
+                            struct dentry *dentry,
+                            reiser4_dir_entry_desc *entry)
+{
+       int result;
+       coord_t *coord;
+       lock_handle lh;
+       reiser4_dentry_fsdata *fsdata;
+       __u64 tograb;
+
+       assert("nikita-1124", dir != NULL);
+       assert("nikita-1125", dentry != NULL);
+
+       tograb = inode_dir_plugin(dir)->estimate.rem_entry(dir);
+       result = reiser4_grab_space(tograb, BA_CAN_COMMIT | BA_RESERVED);
+       if (result != 0)
+               return RETERR(-ENOSPC);
+
+       init_lh(&lh);
+
+       /* check for this entry in a directory. This is plugin method. */
+       result = reiser4_find_entry(dir, dentry, &lh, ZNODE_WRITE_LOCK, entry);
+       fsdata = reiser4_get_dentry_fsdata(dentry);
+       if (IS_ERR(fsdata)) {
+               done_lh(&lh);
+               return PTR_ERR(fsdata);
+       }
+
+       coord = &fsdata->dec.entry_coord;
+
+       assert("nikita-3404",
+              get_inode_oid(dentry->d_inode) != get_inode_oid(dir) ||
+              dir->i_size <= 1);
+
+       coord_clear_iplug(coord);
+       if (result == 0) {
+               /* remove entry. Just pass control to the directory item
+                  plugin. */
+               assert("vs-542", inode_dir_item_plugin(dir));
+               reiser4_seal_done(&fsdata->dec.entry_seal);
+               reiser4_adjust_dir_file(dir, dentry, fsdata->dec.pos, -1);
+               result =
+                   WITH_COORD(coord,
+                              rem_entry(dir, dentry, entry, coord, &lh));
+               if (result == 0) {
+                       if (dir->i_size >= 1)
+                               INODE_DEC_FIELD(dir, i_size);
+                       else {
+                               warning("nikita-2509", "Dir %llu is runt",
+                                       (unsigned long long)
+                                       get_inode_oid(dir));
+                               result = RETERR(-EIO);
+                       }
+
+                       assert("nikita-3405", dentry->d_inode->i_nlink != 1 ||
+                              dentry->d_inode->i_size != 2 ||
+                              inode_dir_plugin(dentry->d_inode) == NULL);
+               }
+       }
+       done_lh(&lh);
+
+       return result;
+}
+
+static reiser4_block_nr estimate_init(struct inode *parent,
+                                     struct inode *object);
+static int create_dot_dotdot(struct inode *object, struct inode *parent);
+
+/* this is common implementation of init method of dir plugin
+   create "." and ".." entries
+*/
+int reiser4_dir_init_common(struct inode *object,      /* new directory */
+                           struct inode *parent,       /* parent directory */
+                           reiser4_object_create_data * data /* info passed
+                                                              * to us, this
+                                                              * is filled by
+                                                              * reiser4()
+                                                              * syscall in
+                                                              * particular */)
+{
+       reiser4_block_nr reserve;
+
+       assert("nikita-680", object != NULL);
+       assert("nikita-681", S_ISDIR(object->i_mode));
+       assert("nikita-682", parent != NULL);
+       assert("nikita-684", data != NULL);
+       assert("nikita-686", data->id == DIRECTORY_FILE_PLUGIN_ID);
+       assert("nikita-687", object->i_mode & S_IFDIR);
+
+       reserve = estimate_init(parent, object);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT))
+               return RETERR(-ENOSPC);
+
+       return create_dot_dotdot(object, parent);
+}
+
+/* this is common implementation of done method of dir plugin
+   remove "." entry
+*/
+int reiser4_dir_done_common(struct inode *object /* object being deleted */ )
+{
+       int result;
+       reiser4_block_nr reserve;
+       struct dentry goodby_dots;
+       reiser4_dir_entry_desc entry;
+
+       assert("nikita-1449", object != NULL);
+
+       if (reiser4_inode_get_flag(object, REISER4_NO_SD))
+               return 0;
+
+       /* of course, this can be rewritten to sweep everything in one
+          reiser4_cut_tree(). */
+       memset(&entry, 0, sizeof entry);
+
+       /* FIXME: this done method is called from reiser4_delete_dir_common which
+        * reserved space already */
+       reserve = inode_dir_plugin(object)->estimate.rem_entry(object);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT | BA_RESERVED))
+               return RETERR(-ENOSPC);
+
+       memset(&goodby_dots, 0, sizeof goodby_dots);
+       entry.obj = goodby_dots.d_inode = object;
+       goodby_dots.d_name.name = ".";
+       goodby_dots.d_name.len = 1;
+       result = reiser4_rem_entry_common(object, &goodby_dots, &entry);
+       reiser4_free_dentry_fsdata(&goodby_dots);
+       if (unlikely(result != 0 && result != -ENOMEM && result != -ENOENT))
+               /* only worth a warning
+
+                  "values of \ eB\ f will give rise to dom!\n"
+                  -- v6src/s2/mv.c:89
+                */
+               warning("nikita-2252", "Cannot remove dot of %lli: %i",
+                       (unsigned long long)get_inode_oid(object), result);
+       return 0;
+}
+
+/* this is common implementation of attach method of dir plugin
+*/
+int reiser4_attach_common(struct inode *child UNUSED_ARG,
+                         struct inode *parent UNUSED_ARG)
+{
+       assert("nikita-2647", child != NULL);
+       assert("nikita-2648", parent != NULL);
+
+       return 0;
+}
+
+/* this is common implementation of detach method of dir plugin
+   remove "..", decrease nlink on parent
+*/
+int reiser4_detach_common(struct inode *object, struct inode *parent)
+{
+       int result;
+       struct dentry goodby_dots;
+       reiser4_dir_entry_desc entry;
+
+       assert("nikita-2885", object != NULL);
+       assert("nikita-2886", !reiser4_inode_get_flag(object, REISER4_NO_SD));
+
+       memset(&entry, 0, sizeof entry);
+
+       /* NOTE-NIKITA this only works if @parent is -the- parent of
+          @object, viz. object whose key is stored in dotdot
+          entry. Wouldn't work with hard-links on directories. */
+       memset(&goodby_dots, 0, sizeof goodby_dots);
+       entry.obj = goodby_dots.d_inode = parent;
+       goodby_dots.d_name.name = "..";
+       goodby_dots.d_name.len = 2;
+       result = reiser4_rem_entry_common(object, &goodby_dots, &entry);
+       reiser4_free_dentry_fsdata(&goodby_dots);
+       if (result == 0) {
+               /* the dot should be the only entry remaining at this time... */
+               assert("nikita-3400",
+                      object->i_size == 1 && object->i_nlink <= 2);
+#if 0
+               /* and, together with the only name directory can have, they
+                * provides for the last 2 remaining references. If we get
+                * here as part of error handling during mkdir, @object
+                * possibly has no name yet, so its nlink == 1. If we get here
+                * from rename (targeting empty directory), it has no name
+                * already, so its nlink == 1. */
+               assert("nikita-3401",
+                      object->i_nlink == 2 || object->i_nlink == 1);
+#endif
+
+               /* decrement nlink of directory removed ".." pointed
+                  to */
+               reiser4_del_nlink(parent, NULL, 0);
+       }
+       return result;
+}
+
+/* this is common implementation of estimate.add_entry method of
+   dir plugin
+   estimation of adding entry which supposes that entry is inserting a
+   unit into item
+*/
+reiser4_block_nr estimate_add_entry_common(const struct inode * inode)
+{
+       return estimate_one_insert_into_item(reiser4_tree_by_inode(inode));
+}
+
+/* this is common implementation of estimate.rem_entry method of dir
+   plugin
+*/
+reiser4_block_nr estimate_rem_entry_common(const struct inode * inode)
+{
+       return estimate_one_item_removal(reiser4_tree_by_inode(inode));
+}
+
+/* this is common implementation of estimate.unlink method of dir
+   plugin
+*/
+reiser4_block_nr
+dir_estimate_unlink_common(const struct inode * parent,
+                          const struct inode * object)
+{
+       reiser4_block_nr res;
+
+       /* hashed_rem_entry(object) */
+       res = inode_dir_plugin(object)->estimate.rem_entry(object);
+       /* del_nlink(parent) */
+       res += 2 * inode_file_plugin(parent)->estimate.update(parent);
+
+       return res;
+}
+
+/*
+ * helper for inode_ops ->lookup() and dir plugin's ->get_parent()
+ * methods: if @inode is a light-weight file, setup its credentials
+ * that are not stored in the stat-data in this case
+ */
+void check_light_weight(struct inode *inode, struct inode *parent)
+{
+       if (reiser4_inode_get_flag(inode, REISER4_LIGHT_WEIGHT)) {
+               inode->i_uid = parent->i_uid;
+               inode->i_gid = parent->i_gid;
+               /* clear light-weight flag. If inode would be read by any
+                  other name, [ug]id wouldn't change. */
+               reiser4_inode_clr_flag(inode, REISER4_LIGHT_WEIGHT);
+       }
+}
+
+/* looks for name specified in @dentry in directory @parent and if name is
+   found - key of object found entry points to is stored in @entry->key */
+int reiser4_lookup_name(struct inode *parent,  /* inode of directory to lookup for
+                                        * name in */
+               struct dentry *dentry,  /* name to look for */
+               reiser4_key * key /* place to store key */ )
+{
+       int result;
+       coord_t *coord;
+       lock_handle lh;
+       const char *name;
+       int len;
+       reiser4_dir_entry_desc entry;
+       reiser4_dentry_fsdata *fsdata;
+
+       assert("nikita-1247", parent != NULL);
+       assert("nikita-1248", dentry != NULL);
+       assert("nikita-1123", dentry->d_name.name != NULL);
+       assert("vs-1486",
+              dentry->d_op == &get_super_private(parent->i_sb)->ops.dentry);
+
+       name = dentry->d_name.name;
+       len = dentry->d_name.len;
+
+       if (!inode_dir_plugin(parent)->is_name_acceptable(parent, name, len))
+               /* some arbitrary error code to return */
+               return RETERR(-ENAMETOOLONG);
+
+       fsdata = reiser4_get_dentry_fsdata(dentry);
+       if (IS_ERR(fsdata))
+               return PTR_ERR(fsdata);
+
+       coord = &fsdata->dec.entry_coord;
+       coord_clear_iplug(coord);
+       init_lh(&lh);
+
+       /* find entry in a directory. This is plugin method. */
+       result = reiser4_find_entry(parent, dentry, &lh, ZNODE_READ_LOCK,
+                                   &entry);
+       if (result == 0) {
+               /* entry was found, extract object key from it. */
+               result =
+                   WITH_COORD(coord,
+                              item_plugin_by_coord(coord)->s.dir.
+                              extract_key(coord, key));
+       }
+       done_lh(&lh);
+       return result;
+
+}
+
+/* helper for reiser4_dir_init_common(): estimate number of blocks to reserve */
+static reiser4_block_nr
+estimate_init(struct inode *parent, struct inode *object)
+{
+       reiser4_block_nr res = 0;
+
+       assert("vpf-321", parent != NULL);
+       assert("vpf-322", object != NULL);
+
+       /* hashed_add_entry(object) */
+       res += inode_dir_plugin(object)->estimate.add_entry(object);
+       /* reiser4_add_nlink(object) */
+       res += inode_file_plugin(object)->estimate.update(object);
+       /* hashed_add_entry(object) */
+       res += inode_dir_plugin(object)->estimate.add_entry(object);
+       /* reiser4_add_nlink(parent) */
+       res += inode_file_plugin(parent)->estimate.update(parent);
+
+       return 0;
+}
+
+/* helper function for reiser4_dir_init_common(). Create "." and ".." */
+static int create_dot_dotdot(struct inode *object /* object to create dot and
+                                                  * dotdot for */ ,
+                            struct inode *parent /* parent of @object */)
+{
+       int result;
+       struct dentry dots_entry;
+       reiser4_dir_entry_desc entry;
+
+       assert("nikita-688", object != NULL);
+       assert("nikita-689", S_ISDIR(object->i_mode));
+       assert("nikita-691", parent != NULL);
+
+       /* We store dot and dotdot as normal directory entries. This is
+          not necessary, because almost all information stored in them
+          is already in the stat-data of directory, the only thing
+          being missed is objectid of grand-parent directory that can
+          easily be added there as extension.
+
+          But it is done the way it is done, because not storing dot
+          and dotdot will lead to the following complications:
+
+          . special case handling in ->lookup().
+          . addition of another extension to the sd.
+          . dependency on key allocation policy for stat data.
+
+        */
+
+       memset(&entry, 0, sizeof entry);
+       memset(&dots_entry, 0, sizeof dots_entry);
+       entry.obj = dots_entry.d_inode = object;
+       dots_entry.d_name.name = ".";
+       dots_entry.d_name.len = 1;
+       result = reiser4_add_entry_common(object, &dots_entry, NULL, &entry);
+       reiser4_free_dentry_fsdata(&dots_entry);
+
+       if (result == 0) {
+               result = reiser4_add_nlink(object, object, 0);
+               if (result == 0) {
+                       entry.obj = dots_entry.d_inode = parent;
+                       dots_entry.d_name.name = "..";
+                       dots_entry.d_name.len = 2;
+                       result = reiser4_add_entry_common(object,
+                                                 &dots_entry, NULL, &entry);
+                       reiser4_free_dentry_fsdata(&dots_entry);
+                       /* if creation of ".." failed, iput() will delete
+                          object with ".". */
+                       if (result == 0) {
+                               result = reiser4_add_nlink(parent, object, 0);
+                               if (result != 0)
+                                       /*
+                                        * if we failed to bump i_nlink, try
+                                        * to remove ".."
+                                        */
+                                       reiser4_detach_common(object, parent);
+                       }
+               }
+       }
+
+       if (result != 0) {
+               /*
+                * in the case of error, at least update stat-data so that,
+                * ->i_nlink updates are not lingering.
+                */
+               reiser4_update_sd(object);
+               reiser4_update_sd(parent);
+       }
+
+       return result;
+}
+
+/*
+ * return 0 iff @coord contains a directory entry for the file with the name
+ * @name.
+ */
+static int
+check_item(const struct inode *dir, const coord_t * coord, const char *name)
+{
+       item_plugin *iplug;
+       char buf[DE_NAME_BUF_LEN];
+
+       iplug = item_plugin_by_coord(coord);
+       if (iplug == NULL) {
+               warning("nikita-1135", "Cannot get item plugin");
+               print_coord("coord", coord, 1);
+               return RETERR(-EIO);
+       } else if (item_id_by_coord(coord) !=
+                  item_id_by_plugin(inode_dir_item_plugin(dir))) {
+               /* item id of current item does not match to id of items a
+                  directory is built of */
+               warning("nikita-1136", "Wrong item plugin");
+               print_coord("coord", coord, 1);
+               return RETERR(-EIO);
+       }
+       assert("nikita-1137", iplug->s.dir.extract_name);
+
+       /* Compare name stored in this entry with name we are looking for.
+
+          NOTE-NIKITA Here should go code for support of something like
+          unicode, code tables, etc.
+        */
+       return !!strcmp(name, iplug->s.dir.extract_name(coord, buf));
+}
+
+static int
+check_entry(const struct inode *dir, coord_t * coord, const struct qstr *name)
+{
+       return WITH_COORD(coord, check_item(dir, coord, name->name));
+}
+
+/*
+ * argument package used by entry_actor to scan entries with identical keys.
+ */
+typedef struct entry_actor_args {
+       /* name we are looking for */
+       const char *name;
+       /* key of directory entry. entry_actor() scans through sequence of
+        * items/units having the same key */
+       reiser4_key *key;
+       /* how many entries with duplicate key was scanned so far. */
+       int non_uniq;
+#if REISER4_USE_COLLISION_LIMIT
+       /* scan limit */
+       int max_non_uniq;
+#endif
+       /* return parameter: set to true, if ->name wasn't found */
+       int not_found;
+       /* what type of lock to take when moving to the next node during
+        * scan */
+       znode_lock_mode mode;
+
+       /* last coord that was visited during scan */
+       coord_t last_coord;
+       /* last node locked during scan */
+       lock_handle last_lh;
+       /* inode of directory */
+       const struct inode *inode;
+} entry_actor_args;
+
+/* Function called by reiser4_find_entry() to look for given name
+   in the directory. */
+static int entry_actor(reiser4_tree * tree UNUSED_ARG /* tree being scanned */ ,
+                      coord_t * coord /* current coord */ ,
+                      lock_handle * lh /* current lock handle */ ,
+                      void *entry_actor_arg /* argument to scan */ )
+{
+       reiser4_key unit_key;
+       entry_actor_args *args;
+
+       assert("nikita-1131", tree != NULL);
+       assert("nikita-1132", coord != NULL);
+       assert("nikita-1133", entry_actor_arg != NULL);
+
+       args = entry_actor_arg;
+       ++args->non_uniq;
+#if REISER4_USE_COLLISION_LIMIT
+       if (args->non_uniq > args->max_non_uniq) {
+               args->not_found = 1;
+               /* hash collision overflow. */
+               return RETERR(-EBUSY);
+       }
+#endif
+
+       /*
+        * did we just reach the end of the sequence of items/units with
+        * identical keys?
+        */
+       if (!keyeq(args->key, unit_key_by_coord(coord, &unit_key))) {
+               assert("nikita-1791",
+                      keylt(args->key, unit_key_by_coord(coord, &unit_key)));
+               args->not_found = 1;
+               args->last_coord.between = AFTER_UNIT;
+               return 0;
+       }
+
+       coord_dup(&args->last_coord, coord);
+       /*
+        * did scan just moved to the next node?
+        */
+       if (args->last_lh.node != lh->node) {
+               int lock_result;
+
+               /*
+                * if so, lock new node with the mode requested by the caller
+                */
+               done_lh(&args->last_lh);
+               assert("nikita-1896", znode_is_any_locked(lh->node));
+               lock_result = longterm_lock_znode(&args->last_lh, lh->node,
+                                                 args->mode, ZNODE_LOCK_HIPRI);
+               if (lock_result != 0)
+                       return lock_result;
+       }
+       return check_item(args->inode, coord, args->name);
+}
+
+/* Look for given @name within directory @dir.
+
+   This is called during lookup, creation and removal of directory
+   entries and on reiser4_rename_common
+
+   First calculate key that directory entry for @name would have. Search
+   for this key in the tree. If such key is found, scan all items with
+   the same key, checking name in each directory entry along the way.
+*/
+int reiser4_find_entry(struct inode *dir,      /* directory to scan */
+                      struct dentry *de,       /* name to search for */
+                      lock_handle * lh,        /* resulting lock handle */
+                      znode_lock_mode mode,    /* required lock mode */
+                      reiser4_dir_entry_desc * entry   /* parameters of found
+                                                          directory entry */)
+{
+       const struct qstr *name;
+       seal_t *seal;
+       coord_t *coord;
+       int result;
+       __u32 flags;
+       de_location *dec;
+       reiser4_dentry_fsdata *fsdata;
+
+       assert("nikita-1130", lh != NULL);
+       assert("nikita-1128", dir != NULL);
+
+       name = &de->d_name;
+       assert("nikita-1129", name != NULL);
+
+       /* dentry private data don't require lock, because dentry
+          manipulations are protected by i_mutex on parent.
+
+          This is not so for inodes, because there is no -the- parent in
+          inode case.
+        */
+       fsdata = reiser4_get_dentry_fsdata(de);
+       if (IS_ERR(fsdata))
+               return PTR_ERR(fsdata);
+       dec = &fsdata->dec;
+
+       coord = &dec->entry_coord;
+       coord_clear_iplug(coord);
+       seal = &dec->entry_seal;
+       /* compose key of directory entry for @name */
+       inode_dir_plugin(dir)->build_entry_key(dir, name, &entry->key);
+
+       if (reiser4_seal_is_set(seal)) {
+               /* check seal */
+               result = reiser4_seal_validate(seal, coord, &entry->key,
+                                              lh, mode, ZNODE_LOCK_LOPRI);
+               if (result == 0) {
+                       /* key was found. Check that it is really item we are
+                          looking for. */
+                       result = check_entry(dir, coord, name);
+                       if (result == 0)
+                               return 0;
+               }
+       }
+       flags = (mode == ZNODE_WRITE_LOCK) ? CBK_FOR_INSERT : 0;
+       /*
+        * find place in the tree where directory item should be located.
+        */
+       result = reiser4_object_lookup(dir, &entry->key, coord, lh, mode,
+                                      FIND_EXACT, LEAF_LEVEL, LEAF_LEVEL,
+                                      flags, NULL /*ra_info */ );
+       if (result == CBK_COORD_FOUND) {
+               entry_actor_args arg;
+
+               /* fast path: no hash collisions */
+               result = check_entry(dir, coord, name);
+               if (result == 0) {
+                       reiser4_seal_init(seal, coord, &entry->key);
+                       dec->pos = 0;
+               } else if (result > 0) {
+                       /* Iterate through all units with the same keys. */
+                       arg.name = name->name;
+                       arg.key = &entry->key;
+                       arg.not_found = 0;
+                       arg.non_uniq = 0;
+#if REISER4_USE_COLLISION_LIMIT
+                       arg.max_non_uniq = max_hash_collisions(dir);
+                       assert("nikita-2851", arg.max_non_uniq > 1);
+#endif
+                       arg.mode = mode;
+                       arg.inode = dir;
+                       coord_init_zero(&arg.last_coord);
+                       init_lh(&arg.last_lh);
+
+                       result = reiser4_iterate_tree
+                               (reiser4_tree_by_inode(dir),
+                                coord, lh,
+                                entry_actor, &arg, mode, 1);
+                       /* if end of the tree or extent was reached during
+                          scanning. */
+                       if (arg.not_found || (result == -E_NO_NEIGHBOR)) {
+                               /* step back */
+                               done_lh(lh);
+
+                               result = zload(arg.last_coord.node);
+                               if (result == 0) {
+                                       coord_clear_iplug(&arg.last_coord);
+                                       coord_dup(coord, &arg.last_coord);
+                                       move_lh(lh, &arg.last_lh);
+                                       result = RETERR(-ENOENT);
+                                       zrelse(arg.last_coord.node);
+                                       --arg.non_uniq;
+                               }
+                       }
+
+                       done_lh(&arg.last_lh);
+                       if (result == 0)
+                               reiser4_seal_init(seal, coord, &entry->key);
+
+                       if (result == 0 || result == -ENOENT) {
+                               assert("nikita-2580", arg.non_uniq > 0);
+                               dec->pos = arg.non_uniq - 1;
+                       }
+               }
+       } else
+               dec->pos = -1;
+       return result;
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format40.c linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format40.c
--- linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format40.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format40.c  2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,655 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../key.h"
+#include "../node/node.h"
+#include "../space/space_allocator.h"
+#include "disk_format40.h"
+#include "../plugin.h"
+#include "../../txnmgr.h"
+#include "../../jnode.h"
+#include "../../tree.h"
+#include "../../super.h"
+#include "../../wander.h"
+#include "../../inode.h"
+#include "../../ktxnmgrd.h"
+#include "../../status_flags.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/buffer_head.h>
+
+/* reiser 4.0 default disk layout */
+
+/* Amount of free blocks needed to perform release_format40 when fs gets
+   mounted RW: 1 for SB, 1 for non-leaves in overwrite set, 2 for tx header
+   & tx record. */
+#define RELEASE_RESERVED 4
+
+/* The greatest supported format40 version number */
+#define FORMAT40_VERSION PLUGIN_LIBRARY_VERSION
+
+/* This flag indicates that backup should be updated
+   (the update is performed by fsck) */
+#define FORMAT40_UPDATE_BACKUP (1 << 31)
+
+/* functions to access fields of format40_disk_super_block */
+static __u64 get_format40_block_count(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->block_count));
+}
+
+static __u64 get_format40_free_blocks(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->free_blocks));
+}
+
+static __u64 get_format40_root_block(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->root_block));
+}
+
+static __u16 get_format40_tree_height(const format40_disk_super_block * sb)
+{
+       return le16_to_cpu(get_unaligned(&sb->tree_height));
+}
+
+static __u64 get_format40_file_count(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->file_count));
+}
+
+static __u64 get_format40_oid(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->oid));
+}
+
+static __u32 get_format40_mkfs_id(const format40_disk_super_block * sb)
+{
+       return le32_to_cpu(get_unaligned(&sb->mkfs_id));
+}
+
+static __u64 get_format40_flags(const format40_disk_super_block * sb)
+{
+       return le64_to_cpu(get_unaligned(&sb->flags));
+}
+
+static __u32 get_format40_version(const format40_disk_super_block * sb)
+{
+       return le32_to_cpu(get_unaligned(&sb->version)) &
+               ~FORMAT40_UPDATE_BACKUP;
+}
+
+static int update_backup_version(const format40_disk_super_block * sb)
+{
+       return (le32_to_cpu(get_unaligned(&sb->version)) &
+               FORMAT40_UPDATE_BACKUP);
+}
+
+static int update_disk_version(const format40_disk_super_block * sb)
+{
+       return (get_format40_version(sb) < FORMAT40_VERSION);
+}
+
+static int incomplete_compatibility(const format40_disk_super_block * sb)
+{
+       return (get_format40_version(sb) > FORMAT40_VERSION);
+}
+
+static format40_super_info *get_sb_info(struct super_block *super)
+{
+       return &get_super_private(super)->u.format40;
+}
+
+static int consult_diskmap(struct super_block *s)
+{
+       format40_super_info *info;
+       journal_location *jloc;
+
+       info = get_sb_info(s);
+       jloc = &get_super_private(s)->jloc;
+       /* Default format-specific locations, if there is nothing in
+        * diskmap */
+       jloc->footer = FORMAT40_JOURNAL_FOOTER_BLOCKNR;
+       jloc->header = FORMAT40_JOURNAL_HEADER_BLOCKNR;
+       info->loc.super = FORMAT40_OFFSET / s->s_blocksize;
+#ifdef CONFIG_REISER4_BADBLOCKS
+       reiser4_get_diskmap_value(FORMAT40_PLUGIN_DISKMAP_ID, FORMAT40_JF,
+                                 &jloc->footer);
+       reiser4_get_diskmap_value(FORMAT40_PLUGIN_DISKMAP_ID, FORMAT40_JH,
+                                 &jloc->header);
+       reiser4_get_diskmap_value(FORMAT40_PLUGIN_DISKMAP_ID, FORMAT40_SUPER,
+                                 &info->loc.super);
+#endif
+       return 0;
+}
+
+/* find any valid super block of disk_format40 (even if the first
+   super block is destroyed), will change block numbers of actual journal header/footer (jf/jh)
+   if needed */
+static struct buffer_head *find_a_disk_format40_super_block(struct super_block
+                                                           *s)
+{
+       struct buffer_head *super_bh;
+       format40_disk_super_block *disk_sb;
+       format40_super_info *info;
+
+       assert("umka-487", s != NULL);
+
+       info = get_sb_info(s);
+
+       super_bh = sb_bread(s, info->loc.super);
+       if (super_bh == NULL)
+               return ERR_PTR(RETERR(-EIO));
+
+       disk_sb = (format40_disk_super_block *) super_bh->b_data;
+       if (strncmp(disk_sb->magic, FORMAT40_MAGIC, sizeof(FORMAT40_MAGIC))) {
+               brelse(super_bh);
+               return ERR_PTR(RETERR(-EINVAL));
+       }
+
+       reiser4_set_block_count(s, le64_to_cpu(get_unaligned(&disk_sb->block_count)));
+       reiser4_set_data_blocks(s, le64_to_cpu(get_unaligned(&disk_sb->block_count)) -
+                               le64_to_cpu(get_unaligned(&disk_sb->free_blocks)));
+       reiser4_set_free_blocks(s, le64_to_cpu(get_unaligned(&disk_sb->free_blocks)));
+
+       return super_bh;
+}
+
+/* find the most recent version of super block. This is called after journal is
+   replayed */
+static struct buffer_head *read_super_block(struct super_block *s UNUSED_ARG)
+{
+       /* Here the most recent superblock copy has to be read. However, as
+          journal replay isn't complete, we are using
+          find_a_disk_format40_super_block() function. */
+       return find_a_disk_format40_super_block(s);
+}
+
+static int get_super_jnode(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+       jnode *sb_jnode;
+       int ret;
+
+       sb_jnode = reiser4_alloc_io_head(&get_sb_info(s)->loc.super);
+
+       ret = jload(sb_jnode);
+
+       if (ret) {
+               reiser4_drop_io_head(sb_jnode);
+               return ret;
+       }
+
+       pin_jnode_data(sb_jnode);
+       jrelse(sb_jnode);
+
+       sbinfo->u.format40.sb_jnode = sb_jnode;
+
+       return 0;
+}
+
+static void done_super_jnode(struct super_block *s)
+{
+       jnode *sb_jnode = get_super_private(s)->u.format40.sb_jnode;
+
+       if (sb_jnode) {
+               unpin_jnode_data(sb_jnode);
+               reiser4_drop_io_head(sb_jnode);
+       }
+}
+
+typedef enum format40_init_stage {
+       NONE_DONE = 0,
+       CONSULT_DISKMAP,
+       FIND_A_SUPER,
+       INIT_JOURNAL_INFO,
+       INIT_STATUS,
+       JOURNAL_REPLAY,
+       READ_SUPER,
+       KEY_CHECK,
+       INIT_OID,
+       INIT_TREE,
+       JOURNAL_RECOVER,
+       INIT_SA,
+       INIT_JNODE,
+       ALL_DONE
+} format40_init_stage;
+
+static format40_disk_super_block *copy_sb(const struct buffer_head *super_bh)
+{
+       format40_disk_super_block *sb_copy;
+
+       sb_copy = kmalloc(sizeof(format40_disk_super_block),
+                         reiser4_ctx_gfp_mask_get());
+       if (sb_copy == NULL)
+               return ERR_PTR(RETERR(-ENOMEM));
+       memcpy(sb_copy, ((format40_disk_super_block *) super_bh->b_data),
+              sizeof(format40_disk_super_block));
+       return sb_copy;
+}
+
+static int check_key_format(const format40_disk_super_block *sb_copy)
+{
+       if (!equi(REISER4_LARGE_KEY,
+                 get_format40_flags(sb_copy) & (1 << FORMAT40_LARGE_KEYS))) {
+               warning("nikita-3228", "Key format mismatch. "
+                       "Only %s keys are supported.",
+                       REISER4_LARGE_KEY ? "large" : "small");
+               return RETERR(-EINVAL);
+       }
+       return 0;
+}
+
+/**
+ * try_init_format40
+ * @super:
+ * @stage:
+ *
+ */
+static int try_init_format40(struct super_block *super,
+                            format40_init_stage *stage)
+{
+       int result;
+       struct buffer_head *super_bh;
+       reiser4_super_info_data *sbinfo;
+       format40_disk_super_block *sb_copy;
+       tree_level height;
+       reiser4_block_nr root_block;
+       node_plugin *nplug;
+
+       assert("vs-475", super != NULL);
+       assert("vs-474", get_super_private(super));
+
+       *stage = NONE_DONE;
+
+       result = consult_diskmap(super);
+       if (result)
+               return result;
+       *stage = CONSULT_DISKMAP;
+
+       super_bh = find_a_disk_format40_super_block(super);
+       if (IS_ERR(super_bh))
+               return PTR_ERR(super_bh);
+       brelse(super_bh);
+       *stage = FIND_A_SUPER;
+
+       /* ok, we are sure that filesystem format is a format40 format */
+
+       /* map jnodes for journal control blocks (header, footer) to disk  */
+       result = reiser4_init_journal_info(super);
+       if (result)
+               return result;
+       *stage = INIT_JOURNAL_INFO;
+
+       /* ok, we are sure that filesystem format is a format40 format */
+       /* Now check it's state */
+       result = reiser4_status_init(FORMAT40_STATUS_BLOCKNR);
+       if (result != 0 && result != -EINVAL)
+               /* -EINVAL means there is no magic, so probably just old
+                * fs. */
+               return result;
+       *stage = INIT_STATUS;
+
+       result = reiser4_status_query(NULL, NULL);
+       if (result == REISER4_STATUS_MOUNT_WARN)
+               notice("vpf-1363", "Warning: mounting %s with errors.",
+                      super->s_id);
+       if (result == REISER4_STATUS_MOUNT_RO)
+               notice("vpf-1364", "Warning: mounting %s with fatal errors,"
+                      " forcing read-only mount.", super->s_id);
+       result = reiser4_journal_replay(super);
+       if (result)
+               return result;
+       *stage = JOURNAL_REPLAY;
+
+       super_bh = read_super_block(super);
+       if (IS_ERR(super_bh))
+               return PTR_ERR(super_bh);
+       *stage = READ_SUPER;
+
+       /* allocate and make a copy of format40_disk_super_block */
+       sb_copy = copy_sb(super_bh);
+       brelse(super_bh);
+
+       if (IS_ERR(sb_copy))
+               return PTR_ERR(sb_copy);
+       printk("reiser4: %s: found disk format 4.0.%u.\n",
+              super->s_id,
+              get_format40_version(sb_copy));
+       if (incomplete_compatibility(sb_copy))
+               printk("reiser4: Warning: The last completely supported "
+                      "version of disk format40 is %u. Some objects of "
+                      "the semantic tree can be unaccessible.\n",
+                      FORMAT40_VERSION);
+       /* make sure that key format of kernel and filesystem match */
+       result = check_key_format(sb_copy);
+       if (result) {
+               kfree(sb_copy);
+               return result;
+       }
+       *stage = KEY_CHECK;
+
+       result = oid_init_allocator(super, get_format40_file_count(sb_copy),
+                                   get_format40_oid(sb_copy));
+       if (result) {
+               kfree(sb_copy);
+               return result;
+       }
+       *stage = INIT_OID;
+
+       /* get things necessary to init reiser4_tree */
+       root_block = get_format40_root_block(sb_copy);
+       height = get_format40_tree_height(sb_copy);
+       nplug = node_plugin_by_id(NODE40_ID);
+
+       /* initialize reiser4_super_info_data */
+       sbinfo = get_super_private(super);
+       assert("", sbinfo->tree.super == super);
+       /* init reiser4_tree for the filesystem */
+       result = reiser4_init_tree(&sbinfo->tree, &root_block, height, nplug);
+       if (result) {
+               kfree(sb_copy);
+               return result;
+       }
+       *stage = INIT_TREE;
+
+       /*
+        * initialize reiser4_super_info_data with data from format40 super
+        * block
+        */
+       sbinfo->default_uid = 0;
+       sbinfo->default_gid = 0;
+       sbinfo->mkfs_id = get_format40_mkfs_id(sb_copy);
+       /* number of blocks in filesystem and reserved space */
+       reiser4_set_block_count(super, get_format40_block_count(sb_copy));
+       sbinfo->blocks_free = get_format40_free_blocks(sb_copy);
+       sbinfo->version = get_format40_version(sb_copy);
+       kfree(sb_copy);
+
+       if (update_backup_version(sb_copy))
+               printk("reiser4: Warning: metadata backup is not updated. "
+                      "Please run 'fsck.reiser4 --fix' on %s.\n",
+                      super->s_id);
+
+       sbinfo->fsuid = 0;
+       sbinfo->fs_flags |= (1 << REISER4_ADG); /* hard links for directories
+                                                * are not supported */
+       sbinfo->fs_flags |= (1 << REISER4_ONE_NODE_PLUGIN);     /* all nodes in
+                                                                * layout 40 are
+                                                                * of one
+                                                                * plugin */
+       /* sbinfo->tmgr is initialized already */
+
+       /* recover sb data which were logged separately from sb block */
+
+       /* NOTE-NIKITA: reiser4_journal_recover_sb_data() calls
+        * oid_init_allocator() and reiser4_set_free_blocks() with new
+        * data. What's the reason to call them above? */
+       result = reiser4_journal_recover_sb_data(super);
+       if (result != 0)
+               return result;
+       *stage = JOURNAL_RECOVER;
+
+       /*
+        * Set number of used blocks.  The number of used blocks is not stored
+        * neither in on-disk super block nor in the journal footer blocks.  At
+        * this moment actual values of total blocks and free block counters
+        * are set in the reiser4 super block (in-memory structure) and we can
+        * calculate number of used blocks from them.
+        */
+       reiser4_set_data_blocks(super,
+                               reiser4_block_count(super) -
+                               reiser4_free_blocks(super));
+
+#if REISER4_DEBUG
+       sbinfo->min_blocks_used = 16 /* reserved area */  +
+               2 /* super blocks */  +
+               2 /* journal footer and header */ ;
+#endif
+
+       /* init disk space allocator */
+       result = sa_init_allocator(reiser4_get_space_allocator(super),
+                                  super, NULL);
+       if (result)
+               return result;
+       *stage = INIT_SA;
+
+       result = get_super_jnode(super);
+       if (result == 0)
+               *stage = ALL_DONE;
+       return result;
+}
+
+/* plugin->u.format.get_ready */
+int init_format_format40(struct super_block *s, void *data UNUSED_ARG)
+{
+       int result;
+       format40_init_stage stage;
+
+       result = try_init_format40(s, &stage);
+       switch (stage) {
+       case ALL_DONE:
+               assert("nikita-3458", result == 0);
+               break;
+       case INIT_JNODE:
+               done_super_jnode(s);
+       case INIT_SA:
+               sa_destroy_allocator(reiser4_get_space_allocator(s), s);
+       case JOURNAL_RECOVER:
+       case INIT_TREE:
+               reiser4_done_tree(&get_super_private(s)->tree);
+       case INIT_OID:
+       case KEY_CHECK:
+       case READ_SUPER:
+       case JOURNAL_REPLAY:
+       case INIT_STATUS:
+               reiser4_status_finish();
+       case INIT_JOURNAL_INFO:
+               reiser4_done_journal_info(s);
+       case FIND_A_SUPER:
+       case CONSULT_DISKMAP:
+       case NONE_DONE:
+               break;
+       default:
+               impossible("nikita-3457", "init stage: %i", stage);
+       }
+
+       if (!rofs_super(s) && reiser4_free_blocks(s) < RELEASE_RESERVED)
+               return RETERR(-ENOSPC);
+
+       return result;
+}
+
+static void pack_format40_super(const struct super_block *s, char *data)
+{
+       format40_disk_super_block *super_data =
+           (format40_disk_super_block *) data;
+
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+
+       assert("zam-591", data != NULL);
+
+       put_unaligned(cpu_to_le64(reiser4_free_committed_blocks(s)),
+                     &super_data->free_blocks);
+
+       put_unaligned(cpu_to_le64(sbinfo->tree.root_block),
+                     &super_data->root_block);
+
+       put_unaligned(cpu_to_le64(oid_next(s)),
+                     &super_data->oid);
+
+       put_unaligned(cpu_to_le64(oids_used(s)),
+                     &super_data->file_count);
+
+       put_unaligned(cpu_to_le16(sbinfo->tree.height),
+                     &super_data->tree_height);
+
+       if (update_disk_version(super_data)) {
+               __u32 version = FORMAT40_VERSION | FORMAT40_UPDATE_BACKUP;
+
+               put_unaligned(cpu_to_le32(version), &super_data->version);
+       }
+}
+
+/* plugin->u.format.log_super
+   return a jnode which should be added to transaction when the super block
+   gets logged */
+jnode *log_super_format40(struct super_block *s)
+{
+       jnode *sb_jnode;
+
+       sb_jnode = get_super_private(s)->u.format40.sb_jnode;
+
+       jload(sb_jnode);
+
+       pack_format40_super(s, jdata(sb_jnode));
+
+       jrelse(sb_jnode);
+
+       return sb_jnode;
+}
+
+/* plugin->u.format.release */
+int release_format40(struct super_block *s)
+{
+       int ret;
+       reiser4_super_info_data *sbinfo;
+
+       sbinfo = get_super_private(s);
+       assert("zam-579", sbinfo != NULL);
+
+       if (!rofs_super(s)) {
+               ret = reiser4_capture_super_block(s);
+               if (ret != 0)
+                       warning("vs-898",
+                               "reiser4_capture_super_block failed: %d",
+                               ret);
+
+               ret = txnmgr_force_commit_all(s, 1);
+               if (ret != 0)
+                       warning("jmacd-74438", "txn_force failed: %d", ret);
+
+               all_grabbed2free();
+       }
+
+       sa_destroy_allocator(&sbinfo->space_allocator, s);
+       reiser4_done_journal_info(s);
+       done_super_jnode(s);
+
+       rcu_barrier();
+       reiser4_done_tree(&sbinfo->tree);
+       /* call finish_rcu(), because some znode were "released" in
+        * reiser4_done_tree(). */
+       rcu_barrier();
+
+       return 0;
+}
+
+#define FORMAT40_ROOT_LOCALITY 41
+#define FORMAT40_ROOT_OBJECTID 42
+
+/* plugin->u.format.root_dir_key */
+const reiser4_key *root_dir_key_format40(const struct super_block *super
+                                        UNUSED_ARG)
+{
+       static const reiser4_key FORMAT40_ROOT_DIR_KEY = {
+               .el = {
+                       __constant_cpu_to_le64((FORMAT40_ROOT_LOCALITY << 4) | KEY_SD_MINOR),
+#if REISER4_LARGE_KEY
+                       ON_LARGE_KEY(0ull,)
+#endif
+                       __constant_cpu_to_le64(FORMAT40_ROOT_OBJECTID),
+                       0ull
+               }
+       };
+
+       return &FORMAT40_ROOT_DIR_KEY;
+}
+
+/* plugin->u.format.check_open.
+   Check the opened object for validness. For now it checks for the valid oid &
+   locality only, can be improved later and it its work may depend on the mount
+   options. */
+int check_open_format40(const struct inode *object)
+{
+       oid_t max, oid;
+
+       max = oid_next(object->i_sb) - 1;
+
+       /* Check the oid. */
+       oid = get_inode_oid(object);
+       if (oid > max) {
+               warning("vpf-1360", "The object with the oid %llu "
+                       "greater then the max used oid %llu found.",
+                       (unsigned long long)oid, (unsigned long long)max);
+
+               return RETERR(-EIO);
+       }
+
+       /* Check the locality. */
+       oid = reiser4_inode_data(object)->locality_id;
+       if (oid > max) {
+               warning("vpf-1361", "The object with the locality %llu "
+                       "greater then the max used oid %llu found.",
+                       (unsigned long long)oid, (unsigned long long)max);
+
+               return RETERR(-EIO);
+       }
+
+       return 0;
+}
+
+/* plugin->u.format.version_update.
+   Perform all version update operations from the on-disk
+   format40_disk_super_block.version on disk to FORMAT40_VERSION.
+ */
+int version_update_format40(struct super_block *super) {
+       txn_handle * trans;
+       lock_handle lh;
+       txn_atom *atom;
+       int ret;
+
+       /* Nothing to do if RO mount or the on-disk version is not less. */
+       if (super->s_flags & MS_RDONLY)
+               return 0;
+
+       if (get_super_private(super)->version >= FORMAT40_VERSION)
+               return 0;
+
+       printk("reiser4: Updating disk format to 4.0.%u. The reiser4 metadata "
+              "backup is left unchanged. Please run 'fsck.reiser4 --fix' "
+              "on %s to update it too.\n", FORMAT40_VERSION, super->s_id);
+
+       /* Mark the uber znode dirty to call log_super on write_logs. */
+       init_lh(&lh);
+       ret = get_uber_znode(reiser4_get_tree(super), ZNODE_WRITE_LOCK,
+                            ZNODE_LOCK_HIPRI, &lh);
+       if (ret != 0)
+               return ret;
+
+       znode_make_dirty(lh.node);
+       done_lh(&lh);
+
+       /* Update the backup blocks. */
+
+       /* Force write_logs immediately. */
+       trans = get_current_context()->trans;
+       atom = get_current_atom_locked();
+       assert("vpf-1906", atom != NULL);
+
+       spin_lock_txnh(trans);
+       return force_commit_atom(trans);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format40.h linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format40.h
--- linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format40.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format40.h  2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,109 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* this file contains:
+   - definition of ondisk super block of standart disk layout for
+     reiser 4.0 (layout 40)
+   - definition of layout 40 specific portion of in-core super block
+   - declarations of functions implementing methods of layout plugin
+     for layout 40
+   - declarations of functions used to get/set fields in layout 40 super block
+*/
+
+#ifndef __DISK_FORMAT40_H__
+#define __DISK_FORMAT40_H__
+
+/* magic for default reiser4 layout */
+#define FORMAT40_MAGIC "ReIsEr40FoRmAt"
+#define FORMAT40_OFFSET (REISER4_MASTER_OFFSET + PAGE_CACHE_SIZE)
+
+#include "../../dformat.h"
+
+#include <linux/fs.h>          /* for struct super_block  */
+
+typedef enum {
+       FORMAT40_LARGE_KEYS
+} format40_flags;
+
+/* ondisk super block for format 40. It is 512 bytes long */
+typedef struct format40_disk_super_block {
+       /*   0 */ d64 block_count;
+       /* number of block in a filesystem */
+       /*   8 */ d64 free_blocks;
+       /* number of free blocks */
+       /*  16 */ d64 root_block;
+       /* filesystem tree root block */
+       /*  24 */ d64 oid;
+       /* smallest free objectid */
+       /*  32 */ d64 file_count;
+       /* number of files in a filesystem */
+       /*  40 */ d64 flushes;
+       /* number of times super block was
+          flushed. Needed if format 40
+          will have few super blocks */
+       /*  48 */ d32 mkfs_id;
+       /* unique identifier of fs */
+       /*  52 */ char magic[16];
+       /* magic string ReIsEr40FoRmAt */
+       /*  68 */ d16 tree_height;
+       /* height of filesystem tree */
+       /*  70 */ d16 formatting_policy;
+       /* not used anymore */
+       /*  72 */ d64 flags;
+       /*  80 */ d32 version;
+       /* on-disk format version number
+          initially assigned by mkfs as the greatest format40
+          version number supported by reiser4progs and updated
+          in mount time in accordance with the greatest format40
+          version number supported by kernel.
+          Is used by fsck to catch possible corruption and
+          for various compatibility issues */
+       /*  84 */ char not_used[428];
+} format40_disk_super_block;
+
+/* format 40 specific part of reiser4_super_info_data */
+typedef struct format40_super_info {
+/*     format40_disk_super_block actual_sb; */
+       jnode *sb_jnode;
+       struct {
+               reiser4_block_nr super;
+       } loc;
+} format40_super_info;
+
+/* Defines for journal header and footer respectively. */
+#define FORMAT40_JOURNAL_HEADER_BLOCKNR \
+       ((REISER4_MASTER_OFFSET / PAGE_CACHE_SIZE) + 3)
+
+#define FORMAT40_JOURNAL_FOOTER_BLOCKNR \
+       ((REISER4_MASTER_OFFSET / PAGE_CACHE_SIZE) + 4)
+
+#define FORMAT40_STATUS_BLOCKNR \
+       ((REISER4_MASTER_OFFSET / PAGE_CACHE_SIZE) + 5)
+
+/* Diskmap declarations */
+#define FORMAT40_PLUGIN_DISKMAP_ID ((REISER4_FORMAT_PLUGIN_TYPE<<16) | (FORMAT40_ID))
+#define FORMAT40_SUPER 1
+#define FORMAT40_JH 2
+#define FORMAT40_JF 3
+
+/* declarations of functions implementing methods of layout plugin for
+   format 40. The functions theirself are in disk_format40.c */
+extern int init_format_format40(struct super_block *, void *data);
+extern const reiser4_key *root_dir_key_format40(const struct super_block *);
+extern int release_format40(struct super_block *s);
+extern jnode *log_super_format40(struct super_block *s);
+extern int check_open_format40(const struct inode *object);
+extern int version_update_format40(struct super_block *super);
+
+/* __DISK_FORMAT40_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format.c linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format.c
--- linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format.c    2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,38 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../debug.h"
+#include "../plugin_header.h"
+#include "disk_format40.h"
+#include "disk_format.h"
+#include "../plugin.h"
+
+/* initialization of disk layout plugins */
+disk_format_plugin format_plugins[LAST_FORMAT_ID] = {
+       [FORMAT40_ID] = {
+               .h = {
+                       .type_id = REISER4_FORMAT_PLUGIN_TYPE,
+                       .id = FORMAT40_ID,
+                       .pops = NULL,
+                       .label = "reiser40",
+                       .desc = "standard disk layout for reiser40",
+                       .linkage = {NULL, NULL}
+               },
+               .init_format = init_format_format40,
+               .root_dir_key = root_dir_key_format40,
+               .release = release_format40,
+               .log_super = log_super_format40,
+               .check_open = check_open_format40,
+               .version_update = version_update_format40
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format.h linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format.h
--- linux-2.6.20.orig/fs/reiser4/plugin/disk_format/disk_format.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/disk_format/disk_format.h    2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,27 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* identifiers for disk layouts, they are also used as indexes in array of disk
+   plugins */
+
+#if !defined( __REISER4_DISK_FORMAT_H__ )
+#define __REISER4_DISK_FORMAT_H__
+
+typedef enum {
+       /* standard reiser4 disk layout plugin id */
+       FORMAT40_ID,
+       LAST_FORMAT_ID
+} disk_format_id;
+
+/* __REISER4_DISK_FORMAT_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/disk_format/Makefile linux-2.6.20/fs/reiser4/plugin/disk_format/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/disk_format/Makefile    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/disk_format/Makefile 2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,5 @@
+obj-$(CONFIG_REISER4_FS) += df_plugins.o
+
+df_plugins-objs :=     \
+       disk_format40.o \
+       disk_format.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/fibration.c linux-2.6.20/fs/reiser4/plugin/fibration.c
--- linux-2.6.20.orig/fs/reiser4/plugin/fibration.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/fibration.c  2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,175 @@
+/* Copyright 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Directory fibrations */
+
+/*
+ * Suppose we have a directory tree with sources of some project. During
+ * compilation .o files are created within this tree. This makes access
+ * to the original source files less efficient, because source files are
+ * now "diluted" by object files: default directory plugin uses prefix
+ * of a file name as a part of the key for directory entry (and this
+ * part is also inherited by the key of file body). This means that
+ * foo.o will be located close to foo.c and foo.h in the tree.
+ *
+ * To avoid this effect directory plugin fill highest 7 (unused
+ * originally) bits of the second component of the directory entry key
+ * by bit-pattern depending on the file name (see
+ * fs/reiser4/kassign.c:build_entry_key_common()). These bits are called
+ * "fibre". Fibre of the file name key is inherited by key of stat data
+ * and keys of file body (in the case of REISER4_LARGE_KEY).
+ *
+ * Fibre for a given file is chosen by per-directory fibration
+ * plugin. Names within given fibre are ordered lexicographically.
+ */
+
+#include "../debug.h"
+#include "plugin_header.h"
+#include "plugin.h"
+#include "../super.h"
+#include "../inode.h"
+
+#include <linux/types.h>
+
+static const int fibre_shift = 57;
+
+#define FIBRE_NO(n) (((__u64)(n)) << fibre_shift)
+
+/*
+ * Trivial fibration: all files of directory are just ordered
+ * lexicographically.
+ */
+static __u64 fibre_trivial(const struct inode *dir, const char *name, int len)
+{
+       return FIBRE_NO(0);
+}
+
+/*
+ * dot-o fibration: place .o files after all others.
+ */
+static __u64 fibre_dot_o(const struct inode *dir, const char *name, int len)
+{
+       /* special treatment for .*\.o */
+       if (len > 2 && name[len - 1] == 'o' && name[len - 2] == '.')
+               return FIBRE_NO(1);
+       else
+               return FIBRE_NO(0);
+}
+
+/*
+ * ext.1 fibration: subdivide directory into 128 fibrations one for each
+ * 7bit extension character (file "foo.h" goes into fibre "h"), plus
+ * default fibre for the rest.
+ */
+static __u64 fibre_ext_1(const struct inode *dir, const char *name, int len)
+{
+       if (len > 2 && name[len - 2] == '.')
+               return FIBRE_NO(name[len - 1]);
+       else
+               return FIBRE_NO(0);
+}
+
+/*
+ * ext.3 fibration: try to separate files with different 3-character
+ * extensions from each other.
+ */
+static __u64 fibre_ext_3(const struct inode *dir, const char *name, int len)
+{
+       if (len > 4 && name[len - 4] == '.')
+               return FIBRE_NO(name[len - 3] + name[len - 2] + name[len - 1]);
+       else
+               return FIBRE_NO(0);
+}
+
+static int change_fibration(struct inode *inode,
+                           reiser4_plugin * plugin,
+                           pset_member memb)
+{
+       int result;
+
+       assert("nikita-3503", inode != NULL);
+       assert("nikita-3504", plugin != NULL);
+
+       assert("nikita-3505", is_reiser4_inode(inode));
+       assert("nikita-3506", inode_dir_plugin(inode) != NULL);
+       assert("nikita-3507",
+              plugin->h.type_id == REISER4_FIBRATION_PLUGIN_TYPE);
+
+       result = 0;
+       if (inode_fibration_plugin(inode) == NULL ||
+           inode_fibration_plugin(inode)->h.id != plugin->h.id) {
+               if (is_dir_empty(inode) == 0)
+                       result = aset_set_unsafe(&reiser4_inode_data(inode)->pset,
+                                                PSET_FIBRATION, plugin);
+               else
+                       result = RETERR(-ENOTEMPTY);
+
+       }
+       return result;
+}
+
+static reiser4_plugin_ops fibration_plugin_ops = {
+       .init = NULL,
+       .load = NULL,
+       .save_len = NULL,
+       .save = NULL,
+       .change = change_fibration
+};
+
+/* fibration plugins */
+fibration_plugin fibration_plugins[LAST_FIBRATION_ID] = {
+       [FIBRATION_LEXICOGRAPHIC] = {
+               .h = {
+                       .type_id = REISER4_FIBRATION_PLUGIN_TYPE,
+                       .id = FIBRATION_LEXICOGRAPHIC,
+                       .pops = &fibration_plugin_ops,
+                       .label = "lexicographic",
+                       .desc = "no fibration",
+                       .linkage = {NULL, NULL}
+               },
+               .fibre = fibre_trivial
+       },
+       [FIBRATION_DOT_O] = {
+               .h = {
+                       .type_id = REISER4_FIBRATION_PLUGIN_TYPE,
+                       .id = FIBRATION_DOT_O,
+                       .pops = &fibration_plugin_ops,
+                       .label = "dot-o",
+                       .desc = "fibrate .o files separately",
+                       .linkage = {NULL, NULL}
+               },
+               .fibre = fibre_dot_o
+       },
+       [FIBRATION_EXT_1] = {
+               .h = {
+                       .type_id = REISER4_FIBRATION_PLUGIN_TYPE,
+                       .id = FIBRATION_EXT_1,
+                       .pops = &fibration_plugin_ops,
+                       .label = "ext-1",
+                       .desc = "fibrate file by single character extension",
+                       .linkage = {NULL, NULL}
+               },
+               .fibre = fibre_ext_1
+       },
+       [FIBRATION_EXT_3] = {
+               .h = {
+                       .type_id = REISER4_FIBRATION_PLUGIN_TYPE,
+                       .id = FIBRATION_EXT_3,
+                       .pops = &fibration_plugin_ops,
+                       .label = "ext-3",
+                       .desc = "fibrate file by three character extension",
+                       .linkage = {NULL, NULL}
+               },
+               .fibre = fibre_ext_3
+       }
+};
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/fibration.h linux-2.6.20/fs/reiser4/plugin/fibration.h
--- linux-2.6.20.orig/fs/reiser4/plugin/fibration.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/fibration.h  2007-05-06 14:50:43.762995722 +0400
@@ -0,0 +1,37 @@
+/* Copyright 2004 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Fibration plugin used by hashed directory plugin to segment content
+ * of directory. See fs/reiser4/plugin/fibration.c for more on this. */
+
+#if !defined( __FS_REISER4_PLUGIN_FIBRATION_H__ )
+#define __FS_REISER4_PLUGIN_FIBRATION_H__
+
+#include "plugin_header.h"
+
+typedef struct fibration_plugin {
+       /* generic fields */
+       plugin_header h;
+
+        __u64(*fibre) (const struct inode * dir, const char *name, int len);
+} fibration_plugin;
+
+typedef enum {
+       FIBRATION_LEXICOGRAPHIC,
+       FIBRATION_DOT_O,
+       FIBRATION_EXT_1,
+       FIBRATION_EXT_3,
+       LAST_FIBRATION_ID
+} reiser4_fibration_id;
+
+/* __FS_REISER4_PLUGIN_FIBRATION_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/cryptcompress.c linux-2.6.20/fs/reiser4/plugin/file/cryptcompress.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/cryptcompress.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/cryptcompress.c 2007-05-06 14:50:43.770998222 +0400
@@ -0,0 +1,3760 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+   reiser4/README */
+
+/* This file contains implementations of inode/file/address_space/file plugin
+ * operations specific for cryptcompress file plugin which manages files with
+ * compressed and encrypted bodies. "Cryptcompress file" is built of items of
+ * CTAIL_ID (see http://www.namesys.com/cryptcompress_design.html for details).
+ */
+
+#include "../../inode.h"
+#include "../cluster.h"
+#include "../object.h"
+#include "../../tree_walk.h"
+#include "cryptcompress.h"
+
+#include <asm/scatterlist.h>
+#include <linux/pagevec.h>
+#include <asm/uaccess.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+#include <linux/random.h>
+
+/* get cryptcompress specific portion of inode */
+cryptcompress_info_t *cryptcompress_inode_data(const struct inode *inode)
+{
+       return &reiser4_inode_data(inode)->file_plugin_data.cryptcompress_info;
+}
+
+/* plugin->u.file.init_inode_data */
+void init_inode_data_cryptcompress(struct inode *inode,
+                                  reiser4_object_create_data * crd,
+                                  int create)
+{
+       cryptcompress_info_t *data;
+
+       data = cryptcompress_inode_data(inode);
+       assert("edward-685", data != NULL);
+
+       memset(data, 0, sizeof(*data));
+
+       turn_on_compression(data);
+       set_lattice_factor(data, MIN_LATTICE_FACTOR);
+       init_inode_ordering(inode, crd, create);
+}
+
+#if REISER4_DEBUG
+int cryptcompress_inode_ok(struct inode *inode)
+{
+       if (!(reiser4_inode_data(inode)->plugin_mask & (1 << PSET_FILE)))
+               return 0;
+       if (!cluster_shift_ok(inode_cluster_shift(inode)))
+               return 0;
+       return 1;
+}
+#endif
+
+/* The following is a part of reiser4 cipher key manager
+   which is called when opening/creating a cryptcompress file */
+
+/* get/set cipher key info */
+crypto_stat_t * inode_crypto_stat (struct inode * inode)
+{
+       assert("edward-90", inode != NULL);
+       assert("edward-91", reiser4_inode_data(inode) != NULL);
+       return cryptcompress_inode_data(inode)->crypt;
+}
+
+static void set_inode_crypto_stat (struct inode * inode, crypto_stat_t * stat)
+{
+       cryptcompress_inode_data(inode)->crypt = stat;
+}
+
+/* allocate a cipher key info */
+crypto_stat_t * reiser4_alloc_crypto_stat (struct inode * inode)
+{
+       crypto_stat_t * info;
+       int fipsize;
+
+       info = kmalloc(sizeof(*info), reiser4_ctx_gfp_mask_get());
+       if (!info)
+               return ERR_PTR(-ENOMEM);
+       memset(info, 0, sizeof (*info));
+       fipsize = inode_digest_plugin(inode)->fipsize;
+       info->keyid = kmalloc(fipsize, reiser4_ctx_gfp_mask_get());
+       if (!info->keyid) {
+               kfree(info);
+               return ERR_PTR(-ENOMEM);
+       }
+       info->host = inode;
+       return info;
+}
+
+#if 0
+/* allocate/free low-level info for cipher and digest
+   transforms */
+static int alloc_crypto_tfms(crypto_stat_t * info)
+{
+       struct crypto_blkcipher * ctfm = NULL;
+       struct crypto_hash      * dtfm = NULL;
+       cipher_plugin * cplug = inode_cipher_plugin(info->host);
+       digest_plugin * dplug = inode_digest_plugin(info->host);
+
+       if (cplug->alloc) {
+               ctfm = cplug->alloc();
+               if (IS_ERR(ctfm)) {
+                       warning("edward-1364",
+                               "Can not allocate info for %s\n",
+                               cplug->h.desc);
+                       return RETERR(PTR_ERR(ctfm));
+               }
+       }
+       info_set_cipher(info, ctfm);
+       if (dplug->alloc) {
+               dtfm = dplug->alloc();
+               if (IS_ERR(dtfm)) {
+                       warning("edward-1365",
+                               "Can not allocate info for %s\n",
+                               dplug->h.desc);
+                       goto unhappy_with_digest;
+               }
+       }
+       info_set_digest(info, dtfm);
+       return 0;
+ unhappy_with_digest:
+       if (cplug->free) {
+               cplug->free(ctfm);
+               info_set_cipher(info, NULL);
+       }
+       return RETERR(PTR_ERR(dtfm));
+}
+#endif
+
+static void
+free_crypto_tfms(crypto_stat_t * info)
+{
+       assert("edward-1366", info != NULL);
+       if (!info_get_cipher(info)) {
+               assert("edward-1601", !info_get_digest(info));
+               return;
+       }
+       inode_cipher_plugin(info->host)->free(info_get_cipher(info));
+       info_set_cipher(info, NULL);
+       inode_digest_plugin(info->host)->free(info_get_digest(info));
+       info_set_digest(info, NULL);
+       return;
+}
+
+#if 0
+/* create a key fingerprint for disk stat-data */
+static int create_keyid (crypto_stat_t * info, crypto_data_t * data)
+{
+       int ret = -ENOMEM;
+       size_t blk, pad;
+       __u8 * dmem;
+       __u8 * cmem;
+       struct hash_desc      ddesc;
+       struct blkcipher_desc cdesc;
+       struct scatterlist sg;
+
+       assert("edward-1367", info != NULL);
+       assert("edward-1368", info->keyid != NULL);
+
+       ddesc.tfm = info_get_digest(info);
+       ddesc.flags = 0;
+       cdesc.tfm = info_get_cipher(info);
+       cdesc.flags = 0;
+
+       dmem = kmalloc((size_t)crypto_hash_digestsize(ddesc.tfm),
+                      reiser4_ctx_gfp_mask_get());
+       if (!dmem)
+               goto exit1;
+
+       blk = crypto_blkcipher_blocksize(cdesc.tfm);
+
+       pad = data->keyid_size % blk;
+       pad = (pad ? blk - pad : 0);
+
+       cmem = kmalloc((size_t)data->keyid_size + pad,
+                      reiser4_ctx_gfp_mask_get());
+       if (!cmem)
+               goto exit2;
+       memcpy(cmem, data->keyid, data->keyid_size);
+       memset(cmem + data->keyid_size, 0, pad);
+
+       sg.page = virt_to_page(cmem);
+       sg.offset = offset_in_page(cmem);
+       sg.length = data->keyid_size + pad;
+
+       ret = crypto_blkcipher_encrypt(&cdesc, &sg, &sg,
+                                      data->keyid_size + pad);
+       if (ret) {
+               warning("edward-1369",
+                       "encryption failed flags=%x\n", cdesc.flags);
+               goto exit3;
+       }
+       ret = crypto_hash_digest(&ddesc, &sg, sg.length, dmem);
+       if (ret) {
+               warning("edward-1602",
+                       "digest failed flags=%x\n", ddesc.flags);
+               goto exit3;
+       }
+       memcpy(info->keyid, dmem, inode_digest_plugin(info->host)->fipsize);
+ exit3:
+       kfree(cmem);
+ exit2:
+       kfree(dmem);
+ exit1:
+       return ret;
+}
+#endif
+
+static void destroy_keyid(crypto_stat_t * info)
+{
+       assert("edward-1370", info != NULL);
+       assert("edward-1371", info->keyid != NULL);
+       kfree(info->keyid);
+       return;
+}
+
+static void __free_crypto_stat (struct inode * inode)
+{
+       crypto_stat_t * info = inode_crypto_stat(inode);
+       assert("edward-1372", info != NULL);
+
+       free_crypto_tfms(info);
+       destroy_keyid(info);
+       kfree(info);
+}
+
+#if 0
+static void instantiate_crypto_stat(crypto_stat_t * info)
+{
+       assert("edward-1373", info != NULL);
+       assert("edward-1374", info->inst == 0);
+       info->inst = 1;
+}
+#endif
+
+static void uninstantiate_crypto_stat(crypto_stat_t * info)
+{
+       assert("edward-1375", info != NULL);
+       info->inst = 0;
+}
+
+static int crypto_stat_instantiated(crypto_stat_t * info)
+{
+       return info->inst;
+}
+
+static int inode_has_cipher_key(struct inode * inode)
+{
+       assert("edward-1376", inode != NULL);
+       return inode_crypto_stat(inode) &&
+               crypto_stat_instantiated(inode_crypto_stat(inode));
+}
+
+static void free_crypto_stat (struct inode * inode)
+{
+       uninstantiate_crypto_stat(inode_crypto_stat(inode));
+       __free_crypto_stat(inode);
+}
+
+static int need_cipher(struct inode * inode)
+{
+       return inode_cipher_plugin(inode) !=
+               cipher_plugin_by_id(NONE_CIPHER_ID);
+}
+
+/* Create a crypto-stat and attach result to the @object.
+   If success is returned, then low-level cipher info contains
+   an instantiated key */
+#if 0
+crypto_stat_t *
+create_crypto_stat(struct inode * object,
+                  crypto_data_t * data /* this contains a (uninstantiated)
+                                          cipher key imported from user
+                                          space */)
+{
+       int ret;
+       crypto_stat_t * info;
+
+       assert("edward-1377", data != NULL);
+       assert("edward-1378", need_cipher(object));
+
+       if (inode_file_plugin(object) !=
+           file_plugin_by_id(DIRECTORY_FILE_PLUGIN_ID))
+               return ERR_PTR(-EINVAL);
+
+       info = reiser4_alloc_crypto_stat(object);
+       if (IS_ERR(info))
+               return info;
+       ret = alloc_crypto_tfms(info);
+       if (ret)
+               goto err;
+       /* instantiating a key */
+       ret = crypto_blkcipher_setkey(info_get_cipher(info),
+                                     data->key,
+                                     data->keysize);
+       if (ret) {
+               warning("edward-1379",
+                       "setkey failed flags=%x\n",
+                       crypto_blkcipher_get_flags(info_get_cipher(info)));
+               goto err;
+       }
+       info->keysize = data->keysize;
+       ret = create_keyid(info, data);
+       if (ret)
+               goto err;
+       instantiate_crypto_stat(info);
+       return info;
+ err:
+       __free_crypto_stat(object);
+       return ERR_PTR(ret);
+}
+#endif
+
+/* increment/decrement a load counter when
+   attaching/detaching the crypto-stat to any object */
+static void load_crypto_stat(crypto_stat_t * info)
+{
+       assert("edward-1380", info != NULL);
+       inc_keyload_count(info);
+}
+
+static void unload_crypto_stat(struct inode * inode)
+{
+       crypto_stat_t * info = inode_crypto_stat(inode);
+       assert("edward-1381", info->keyload_count > 0);
+
+       dec_keyload_count(inode_crypto_stat(inode));
+       if (info->keyload_count == 0)
+               /* final release */
+               free_crypto_stat(inode);
+}
+
+/* attach/detach an existing crypto-stat */
+void reiser4_attach_crypto_stat(struct inode * inode, crypto_stat_t * info)
+{
+       assert("edward-1382", inode != NULL);
+       assert("edward-1383", info != NULL);
+       assert("edward-1384", inode_crypto_stat(inode) == NULL);
+
+       set_inode_crypto_stat(inode, info);
+       load_crypto_stat(info);
+}
+
+/* returns true, if crypto stat can be attached to the @host */
+#if REISER4_DEBUG
+static int host_allows_crypto_stat(struct inode * host)
+{
+       int ret;
+       file_plugin * fplug = inode_file_plugin(host);
+
+       switch (fplug->h.id) {
+       case CRYPTCOMPRESS_FILE_PLUGIN_ID:
+               ret = 1;
+               break;
+       default:
+               ret = 0;
+       }
+       return ret;
+}
+#endif  /*  REISER4_DEBUG  */
+
+static void reiser4_detach_crypto_stat(struct inode * inode)
+{
+       assert("edward-1385", inode != NULL);
+       assert("edward-1386", host_allows_crypto_stat(inode));
+
+       if (inode_crypto_stat(inode))
+               unload_crypto_stat(inode);
+       set_inode_crypto_stat(inode, NULL);
+}
+
+#if 0
+
+/* compare fingerprints of @child and @parent */
+static int keyid_eq(crypto_stat_t * child, crypto_stat_t * parent)
+{
+       return !memcmp(child->keyid, parent->keyid, info_digest_plugin(parent)->fipsize);
+}
+
+/* check if a crypto-stat (which is bound to @parent) can be inherited */
+int can_inherit_crypto_cryptcompress(struct inode *child, struct inode *parent)
+{
+       if (!need_cipher(child))
+               return 0;
+       /* the child is created */
+       if (!inode_crypto_stat(child))
+               return 1;
+       /* the child is looked up */
+       if (!inode_crypto_stat(parent))
+               return 0;
+       return (inode_cipher_plugin(child) == inode_cipher_plugin(parent) &&
+               inode_digest_plugin(child) == inode_digest_plugin(parent) &&
+               inode_crypto_stat(child)->keysize == inode_crypto_stat(parent)->keysize &&
+               keyid_eq(inode_crypto_stat(child), inode_crypto_stat(parent)));
+}
+#endif
+
+/* helper functions for ->create() method of the cryptcompress plugin */
+static int inode_set_crypto(struct inode * object)
+{
+       reiser4_inode * info;
+       if (!inode_crypto_stat(object)) {
+               if (need_cipher(object))
+                       return RETERR(-EINVAL);
+               /* the file is not to be encrypted */
+               return 0;
+       }
+       info = reiser4_inode_data(object);
+       info->extmask |= (1 << CRYPTO_STAT);
+       return 0;
+}
+
+static int inode_init_compression(struct inode * object)
+{
+       int result = 0;
+       assert("edward-1461", object != NULL);
+       if (inode_compression_plugin(object)->init)
+               result = inode_compression_plugin(object)->init();
+       return result;
+}
+
+static int inode_check_cluster(struct inode * object)
+{
+       assert("edward-696", object != NULL);
+
+       if (inode_cluster_size(object) < PAGE_CACHE_SIZE) {
+               warning("edward-1320", "Can not support '%s' "
+                       "logical clusters (less then page size)",
+                       inode_cluster_plugin(object)->h.label);
+               return RETERR(-EINVAL);
+       }
+       return 0;
+}
+
+/* ->destroy_inode() method of the cryptcompress plugin */
+void destroy_inode_cryptcompress(struct inode * inode)
+{
+       assert("edward-23", cryptcompress_inode_data(inode)->pgcount == 0);
+       reiser4_detach_crypto_stat(inode);
+       return;
+}
+
+/* ->create() method of the cryptcompress plugin
+
+. install plugins
+. attach crypto info if specified
+. attach compression info if specified
+. attach cluster info
+*/
+int
+create_cryptcompress(struct inode *object, struct inode *parent,
+                    reiser4_object_create_data * data)
+{
+       int result;
+       reiser4_inode *info;
+
+       assert("edward-23", object != NULL);
+       assert("edward-24", parent != NULL);
+       assert("edward-30", data != NULL);
+       assert("edward-26", reiser4_inode_get_flag(object, REISER4_NO_SD));
+       assert("edward-27", data->id == CRYPTCOMPRESS_FILE_PLUGIN_ID);
+
+       info = reiser4_inode_data(object);
+
+       assert("edward-29", info != NULL);
+
+       /* set file bit */
+       info->plugin_mask |= (1 << PSET_FILE);
+
+       /* set crypto */
+       result = inode_set_crypto(object);
+       if (result)
+               goto error;
+       /* set compression */
+       result = inode_init_compression(object);
+       if (result)
+               goto error;
+       /* set cluster */
+       result = inode_check_cluster(object);
+       if (result)
+               goto error;
+
+       /* save everything in disk stat-data */
+       result = write_sd_by_inode_common(object);
+       if (!result)
+               return 0;
+ error:
+       reiser4_detach_crypto_stat(object);
+       return result;
+}
+
+/* ->open() method of the cryptcompress plugin */
+int open_object_cryptcompress(struct inode * inode, struct file * file)
+{
+       int result;
+       struct inode * parent;
+
+       assert("edward-1394", inode != NULL);
+       assert("edward-1395", file != NULL);
+       assert("edward-1396", file != NULL);
+       assert("edward-1397", file->f_dentry->d_inode == inode);
+       assert("edward-1398", file->f_dentry->d_parent != NULL);
+       assert("edward-1399", file->f_dentry->d_parent->d_inode != NULL);
+       assert("edward-698",
+              inode_file_plugin(inode) ==
+              file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID));
+       result = inode_check_cluster(inode);
+       if (result)
+               return result;
+       result = inode_init_compression(inode);
+       if (result)
+               return result;
+       if (!need_cipher(inode))
+               /* the file is not to be ciphered */
+               return 0;
+       parent = file->f_dentry->d_parent->d_inode;
+       if (!inode_has_cipher_key(inode))
+               return RETERR(-EINVAL);
+       return 0;
+}
+
+/* returns a blocksize, the attribute of a cipher algorithm */
+static unsigned int
+cipher_blocksize(struct inode * inode)
+{
+       assert("edward-758", need_cipher(inode));
+       assert("edward-1400", inode_crypto_stat(inode) != NULL);
+       return crypto_blkcipher_blocksize
+               (info_get_cipher(inode_crypto_stat(inode)));
+}
+
+/* returns offset translated by scale factor of the crypto-algorithm */
+static loff_t inode_scaled_offset (struct inode * inode,
+                                  const loff_t src_off /* input offset */)
+{
+       assert("edward-97", inode != NULL);
+
+       if (!need_cipher(inode) ||
+           src_off == get_key_offset(reiser4_min_key()) ||
+           src_off == get_key_offset(reiser4_max_key()))
+               return src_off;
+
+       return inode_cipher_plugin(inode)->scale(inode,
+                                                cipher_blocksize(inode),
+                                                src_off);
+}
+
+/* returns disk cluster size */
+size_t inode_scaled_cluster_size(struct inode * inode)
+{
+       assert("edward-110", inode != NULL);
+
+       return inode_scaled_offset(inode, inode_cluster_size(inode));
+}
+
+static int new_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       return (clust_to_off(clust->index, inode) >= inode->i_size);
+}
+
+/* set number of cluster pages */
+static void set_cluster_nrpages(reiser4_cluster_t * clust, struct inode *inode)
+{
+       reiser4_slide_t *win;
+
+       assert("edward-180", clust != NULL);
+       assert("edward-1040", inode != NULL);
+
+       win = clust->win;
+       if (!win) {
+               /* NOTE-EDWARD: i_size should be protected */
+               clust->nr_pages =
+                   count_to_nrpages(fsize_to_count(clust, inode));
+               return;
+       }
+       assert("edward-1176", clust->op != PCL_UNKNOWN);
+       assert("edward-1064", win->off + win->count + win->delta != 0);
+
+       if (win->stat == HOLE_WINDOW &&
+           win->off == 0 && win->count == inode_cluster_size(inode)) {
+               /* special case: we start write hole from fake cluster */
+               clust->nr_pages = 0;
+               return;
+       }
+       clust->nr_pages =
+           count_to_nrpages(max_count(win->off + win->count + win->delta,
+                                      fsize_to_count(clust, inode)));
+       return;
+}
+
+/* ->key_by_inode() method of the cryptcompress plugin */
+/* see plugin/plugin.h for details */
+int
+key_by_inode_cryptcompress(struct inode *inode, loff_t off, reiser4_key * key)
+{
+       loff_t clust_off;
+
+       assert("edward-64", inode != 0);
+       //      assert("edward-112", ergo(off != get_key_offset(reiser4_max_key()), !off_to_cloff(off, inode)));
+       /* don't come here with other offsets */
+
+       clust_off =
+           (off ==
+            get_key_offset(reiser4_max_key())? get_key_offset(reiser4_max_key()) :
+            off_to_clust_to_off(off, inode));
+
+       key_by_inode_and_offset_common(inode, 0, key);
+       set_key_offset(key,
+                      (__u64) (!inode_crypto_stat(inode) ? clust_off :
+                               inode_scaled_offset(inode, clust_off)));
+       return 0;
+}
+
+/* plugin->flow_by_inode */
+int
+flow_by_inode_cryptcompress(struct inode *inode /* file to build flow for */ ,
+                           const char __user *buf /* user level buffer */ ,
+                           int user    /* 1 if @buf is of user space, 0 - if it is
+                                          kernel space */ ,
+                           loff_t size /* buffer size */ ,
+                           loff_t off /* offset to start io from */ ,
+                           rw_op op /* READ or WRITE */ ,
+                           flow_t * f /* resulting flow */ )
+{
+       assert("edward-436", f != NULL);
+       assert("edward-149", inode != NULL);
+       assert("edward-150", inode_file_plugin(inode) != NULL);
+
+       f->length = size;
+       memcpy(&f->data, &buf, sizeof(buf));
+       f->user = user;
+       f->op = op;
+
+       if (op == WRITE_OP && user == 1)
+               return 0;
+       return key_by_inode_cryptcompress(inode, off, &f->key);
+}
+
+static int
+cryptcompress_hint_validate(hint_t * hint, const reiser4_key * key,
+                           znode_lock_mode lock_mode)
+{
+       coord_t *coord;
+
+       assert("edward-704", hint != NULL);
+       assert("edward-1089", !hint_is_valid(hint));
+       assert("edward-706", hint->lh.owner == NULL);
+
+       coord = &hint->ext_coord.coord;
+
+       if (!hint || !hint_is_set(hint) || hint->mode != lock_mode)
+               /* hint either not set or set by different operation */
+               return RETERR(-E_REPEAT);
+
+       if (get_key_offset(key) != hint->offset)
+               /* hint is set for different key */
+               return RETERR(-E_REPEAT);
+
+       assert("edward-707", reiser4_schedulable());
+
+       return reiser4_seal_validate(&hint->seal, &hint->ext_coord.coord,
+                                    key, &hint->lh, lock_mode,
+                                    ZNODE_LOCK_LOPRI);
+}
+
+/* reserve disk space when writing a logical cluster */
+static int reserve4cluster(struct inode *inode, reiser4_cluster_t *clust)
+{
+       int result = 0;
+
+       assert("edward-965", reiser4_schedulable());
+       assert("edward-439", inode != NULL);
+       assert("edward-440", clust != NULL);
+       assert("edward-441", clust->pages != NULL);
+
+       if (clust->nr_pages == 0) {
+               assert("edward-1152", clust->win != NULL);
+               assert("edward-1153", clust->win->stat == HOLE_WINDOW);
+               /* don't reserve space for fake disk clusteer */
+               return 0;
+       }
+       assert("edward-442", jprivate(clust->pages[0]) != NULL);
+
+       result = reiser4_grab_space_force(estimate_insert_cluster(inode) +
+                                         estimate_update_cluster(inode),
+                                         BA_CAN_COMMIT);
+       if (result)
+               return result;
+       clust->reserved = 1;
+       grabbed2cluster_reserved(estimate_insert_cluster(inode) +
+                                estimate_update_cluster(inode));
+#if REISER4_DEBUG
+       clust->reserved_prepped = estimate_update_cluster(inode);
+       clust->reserved_unprepped = estimate_insert_cluster(inode);
+#endif
+       /* there can be space grabbed by txnmgr_force_commit_all */
+       return 0;
+}
+
+/* free reserved disk space if writing a logical cluster fails */
+static void
+free_reserved4cluster(struct inode *inode, reiser4_cluster_t * clust, int count)
+{
+       assert("edward-967", clust->reserved == 1);
+
+       cluster_reserved2free(count);
+       clust->reserved = 0;
+}
+
+/* The core search procedure of the cryptcompress plugin.
+   If returned value is not cbk_errored, then current znode is locked */
+static int find_cluster_item(hint_t * hint,
+                            const reiser4_key * key, /* key of the item we are
+                                                        looking for */
+                            znode_lock_mode lock_mode /* which lock */ ,
+                            ra_info_t * ra_info, lookup_bias bias, __u32 flags)
+{
+       int result;
+       reiser4_key ikey;
+       int went_right = 0;
+       coord_t *coord = &hint->ext_coord.coord;
+       coord_t orig = *coord;
+
+       assert("edward-152", hint != NULL);
+
+       if (!hint_is_valid(hint)) {
+               result = cryptcompress_hint_validate(hint, key, lock_mode);
+               if (result == -E_REPEAT)
+                       goto traverse_tree;
+               else if (result) {
+                       assert("edward-1216", 0);
+                       return result;
+               }
+               hint_set_valid(hint);
+       }
+       assert("edward-709", znode_is_any_locked(coord->node));
+
+       /* In-place lookup is going here, it means we just need to
+          check if next item of the @coord match to the @keyhint) */
+
+       if (equal_to_rdk(coord->node, key)) {
+               result = goto_right_neighbor(coord, &hint->lh);
+               if (result == -E_NO_NEIGHBOR) {
+                       assert("edward-1217", 0);
+                       return RETERR(-EIO);
+               }
+               if (result)
+                       return result;
+               assert("edward-1218", equal_to_ldk(coord->node, key));
+               went_right = 1;
+       } else {
+               coord->item_pos++;
+               coord->unit_pos = 0;
+               coord->between = AT_UNIT;
+       }
+       result = zload(coord->node);
+       if (result)
+               return result;
+       assert("edward-1219", !node_is_empty(coord->node));
+
+       if (!coord_is_existing_item(coord)) {
+               zrelse(coord->node);
+               goto not_found;
+       }
+       item_key_by_coord(coord, &ikey);
+       zrelse(coord->node);
+       if (!keyeq(key, &ikey))
+               goto not_found;
+       /* Ok, item is found, update node counts */
+       if (went_right)
+               dclust_inc_extension_ncount(hint);
+       return CBK_COORD_FOUND;
+
+      not_found:
+       assert("edward-1220", coord->item_pos > 0);
+       //coord->item_pos--;
+       /* roll back */
+       *coord = orig;
+       ON_DEBUG(coord_update_v(coord));
+       return CBK_COORD_NOTFOUND;
+
+      traverse_tree:
+       assert("edward-713", hint->lh.owner == NULL);
+       assert("edward-714", reiser4_schedulable());
+
+       reiser4_unset_hint(hint);
+       dclust_init_extension(hint);
+       coord_init_zero(coord);
+       result = coord_by_key(current_tree, key, coord, &hint->lh,
+                             lock_mode, bias, LEAF_LEVEL, LEAF_LEVEL,
+                             CBK_UNIQUE | flags, ra_info);
+       if (cbk_errored(result))
+               return result;
+       if(result == CBK_COORD_FOUND)
+               dclust_inc_extension_ncount(hint);
+       hint_set_valid(hint);
+       return result;
+}
+
+/* This function is called by deflate[inflate] manager when
+   creating a transformed/plain stream to check if we should
+   create/cut some overhead. If this returns true, then @oh
+   contains the size of this overhead.
+ */
+static int
+need_cut_or_align(struct inode * inode, reiser4_cluster_t * clust,
+                 rw_op rw, int * oh)
+{
+       tfm_cluster_t * tc = &clust->tc;
+       switch (rw) {
+       case WRITE_OP: /* estimate align */
+               *oh = tc->len % cipher_blocksize(inode);
+               if (*oh != 0)
+                       return 1;
+               break;
+       case READ_OP:  /* estimate cut */
+               *oh = *(tfm_output_data(clust) + tc->len - 1);
+               break;
+       default:
+               impossible("edward-1401", "bad option");
+       }
+       return (tc->len != tc->lsize);
+}
+
+/* create/cut an overhead of transformed/plain stream */
+static void
+align_or_cut_overhead(struct inode * inode, reiser4_cluster_t * clust, rw_op rw)
+{
+       int oh;
+       cipher_plugin * cplug = inode_cipher_plugin(inode);
+
+       assert("edward-1402", need_cipher(inode));
+
+       if (!need_cut_or_align(inode, clust, rw, &oh))
+               return;
+       switch (rw) {
+       case WRITE_OP: /* do align */
+               clust->tc.len +=
+                       cplug->align_stream(tfm_input_data(clust) +
+                                           clust->tc.len, clust->tc.len,
+                                           cipher_blocksize(inode));
+               *(tfm_input_data(clust) + clust->tc.len - 1) =
+                       cipher_blocksize(inode) - oh;
+               break;
+       case READ_OP: /* do cut */
+               assert("edward-1403", oh <= cipher_blocksize(inode));
+               clust->tc.len -= oh;
+               break;
+       default:
+               impossible("edward-1404", "bad option");
+       }
+       return;
+}
+
+/* the following two functions are to evaluate results
+   of compression transform */
+static unsigned
+max_cipher_overhead(struct inode * inode)
+{
+       if (!need_cipher(inode) || !inode_cipher_plugin(inode)->align_stream)
+               return 0;
+       return cipher_blocksize(inode);
+}
+
+static int deflate_overhead(struct inode *inode)
+{
+       return (inode_compression_plugin(inode)->
+               checksum ? DC_CHECKSUM_SIZE : 0);
+}
+
+static unsigned deflate_overrun(struct inode * inode, int ilen)
+{
+       return coa_overrun(inode_compression_plugin(inode), ilen);
+}
+
+/* Estimating compressibility of a logical cluster by various
+   policies represented by compression mode plugin.
+   If this returns false, then compressor won't be called for
+   the cluster of index @index.
+*/
+static int should_compress(tfm_cluster_t * tc, cloff_t index,
+                          struct inode *inode)
+{
+       compression_plugin *cplug = inode_compression_plugin(inode);
+       compression_mode_plugin *mplug = inode_compression_mode_plugin(inode);
+
+       assert("edward-1321", tc->len != 0);
+       assert("edward-1322", cplug != NULL);
+       assert("edward-1323", mplug != NULL);
+
+       return /* estimate by size */
+               (cplug->min_size_deflate ?
+                tc->len >= cplug->min_size_deflate() :
+                1) &&
+               /* estimate by compression mode plugin */
+               (mplug->should_deflate ?
+                mplug->should_deflate(inode, index) :
+                1);
+}
+
+/* Evaluating results of compression transform.
+   Returns true, if we need to accept this results */
+static int
+save_compressed(int size_before, int size_after, struct inode * inode)
+{
+       return (size_after + deflate_overhead(inode) +
+               max_cipher_overhead(inode) < size_before);
+}
+
+/* Guess result of the evaluation above */
+static int
+need_inflate(reiser4_cluster_t * clust, struct inode *inode,
+            int encrypted /* is cluster encrypted */ )
+{
+       tfm_cluster_t *tc = &clust->tc;
+
+       assert("edward-142", tc != 0);
+       assert("edward-143", inode != NULL);
+
+       return tc->len <
+           (encrypted ?
+            inode_scaled_offset(inode, tc->lsize) :
+            tc->lsize);
+}
+
+/* If results of compression were accepted, then we add
+   a checksum to catch possible disk cluster corruption.
+   The following is a format of the data stored in disk clusters:
+
+                  data                   This is (transformed) logical cluster.
+                  cipher_overhead        This is created by ->align() method
+                                          of cipher plugin. May be absent.
+                  checksum          (4)  This is created by ->checksum method
+                                          of compression plugin to check
+                                          integrity. May be absent.
+
+                  Crypto overhead format:
+
+                  data
+                  control_byte      (1)   contains aligned overhead size:
+                                          1 <= overhead <= cipher_blksize
+*/
+/* Append a checksum at the end of a transformed stream */
+static void dc_set_checksum(compression_plugin * cplug, tfm_cluster_t * tc)
+{
+       __u32 checksum;
+
+       assert("edward-1309", tc != NULL);
+       assert("edward-1310", tc->len > 0);
+       assert("edward-1311", cplug->checksum != NULL);
+
+       checksum = cplug->checksum(tfm_stream_data(tc, OUTPUT_STREAM), tc->len);
+       put_unaligned(cpu_to_le32(checksum),
+                (d32 *)(tfm_stream_data(tc, OUTPUT_STREAM) + tc->len));
+       tc->len += (int)DC_CHECKSUM_SIZE;
+}
+
+/* Check a disk cluster checksum.
+   Returns 0 if checksum is correct, otherwise returns 1 */
+static int dc_check_checksum(compression_plugin * cplug, tfm_cluster_t * tc)
+{
+       assert("edward-1312", tc != NULL);
+       assert("edward-1313", tc->len > (int)DC_CHECKSUM_SIZE);
+       assert("edward-1314", cplug->checksum != NULL);
+
+       if (cplug->checksum(tfm_stream_data(tc, INPUT_STREAM),
+                           tc->len - (int)DC_CHECKSUM_SIZE) !=
+           le32_to_cpu(get_unaligned((d32 *)
+                                     (tfm_stream_data(tc, INPUT_STREAM)
+                                      + tc->len - (int)DC_CHECKSUM_SIZE)))) {
+               warning("edward-156",
+                       "Bad disk cluster checksum %d, (should be %d) Fsck?\n",
+                       (int)le32_to_cpu
+                       (get_unaligned((d32 *)
+                                      (tfm_stream_data(tc, INPUT_STREAM) +
+                                       tc->len - (int)DC_CHECKSUM_SIZE))),
+                       (int)cplug->checksum
+                       (tfm_stream_data(tc, INPUT_STREAM),
+                        tc->len - (int)DC_CHECKSUM_SIZE));
+               return 1;
+       }
+       tc->len -= (int)DC_CHECKSUM_SIZE;
+       return 0;
+}
+
+/* get input/output stream for some transform action */
+int grab_tfm_stream(struct inode * inode, tfm_cluster_t * tc,
+                   tfm_stream_id id)
+{
+       size_t size = inode_scaled_cluster_size(inode);
+
+       assert("edward-901", tc != NULL);
+       assert("edward-1027", inode_compression_plugin(inode) != NULL);
+
+       if (cluster_get_tfm_act(tc) == TFMA_WRITE)
+               size += deflate_overrun(inode, inode_cluster_size(inode));
+
+       if (!tfm_stream(tc, id) && id == INPUT_STREAM)
+               alternate_streams(tc);
+       if (!tfm_stream(tc, id))
+               return alloc_tfm_stream(tc, size, id);
+
+       assert("edward-902", tfm_stream_is_set(tc, id));
+
+       if (tfm_stream_size(tc, id) < size)
+               return realloc_tfm_stream(tc, size, id);
+       return 0;
+}
+
+/* Common deflate manager */
+int reiser4_deflate_cluster(reiser4_cluster_t * clust, struct inode * inode)
+{
+       int result = 0;
+       int compressed = 0;
+       int encrypted = 0;
+       tfm_cluster_t * tc = &clust->tc;
+       compression_plugin * coplug;
+
+       assert("edward-401", inode != NULL);
+       assert("edward-903", tfm_stream_is_set(tc, INPUT_STREAM));
+       assert("edward-1348", cluster_get_tfm_act(tc) == TFMA_WRITE);
+       assert("edward-498", !tfm_cluster_is_uptodate(tc));
+
+       coplug = inode_compression_plugin(inode);
+       if (should_compress(tc, clust->index, inode)) {
+               /* try to compress, discard bad results */
+               __u32 dst_len;
+               compression_mode_plugin * mplug =
+                       inode_compression_mode_plugin(inode);
+               assert("edward-602", coplug != NULL);
+               assert("edward-1423", coplug->compress != NULL);
+
+               result = grab_coa(tc, coplug);
+               if (result) {
+                   warning("edward-1424",
+                           "alloc_coa failed with ret=%d, skipped compression",
+                           result);
+                   goto cipher;
+               }
+               result = grab_tfm_stream(inode, tc, OUTPUT_STREAM);
+               if (result) {
+                   warning("edward-1425",
+                        "alloc stream failed with ret=%d, skipped compression",
+                           result);
+                   goto cipher;
+               }
+               dst_len = tfm_stream_size(tc, OUTPUT_STREAM);
+               coplug->compress(get_coa(tc, coplug->h.id, tc->act),
+                                tfm_input_data(clust), tc->len,
+                                tfm_output_data(clust), &dst_len);
+               /* make sure we didn't overwrite extra bytes */
+               assert("edward-603",
+                      dst_len <= tfm_stream_size(tc, OUTPUT_STREAM));
+
+               /* evaluate results of compression transform */
+               if (save_compressed(tc->len, dst_len, inode)) {
+                       /* good result, accept */
+                       tc->len = dst_len;
+                       if (mplug->accept_hook != NULL) {
+                              result = mplug->accept_hook(inode, clust->index);
+                              if (result)
+                                      warning("edward-1426",
+                                              "accept_hook failed with ret=%d",
+                                              result);
+                       }
+                       compressed = 1;
+               }
+               else {
+                       /* bad result, discard */
+#if REISER4_DEBUG
+                       if (cluster_is_complete(clust, inode))
+                             warning("edward-1338",
+                                     "incompressible cluster %lu (inode %llu)",
+                                     clust->index,
+                                     (unsigned long long)get_inode_oid(inode));
+#endif
+                       if (mplug->discard_hook != NULL &&
+                           cluster_is_complete(clust, inode)) {
+                               result = mplug->discard_hook(inode,
+                                                            clust->index);
+                               if (result)
+                                     warning("edward-1427",
+                                             "discard_hook failed with ret=%d",
+                                             result);
+                       }
+               }
+       }
+ cipher:
+       if (need_cipher(inode)) {
+               cipher_plugin * ciplug;
+               struct blkcipher_desc desc;
+               struct scatterlist src;
+               struct scatterlist dst;
+
+               ciplug = inode_cipher_plugin(inode);
+               desc.tfm = info_get_cipher(inode_crypto_stat(inode));
+               desc.flags = 0;
+               if (compressed)
+                       alternate_streams(tc);
+               result = grab_tfm_stream(inode, tc, OUTPUT_STREAM);
+               if (result)
+                       return result;
+
+               align_or_cut_overhead(inode, clust, WRITE_OP);
+               src.page = virt_to_page(tfm_input_data(clust));
+               src.offset = offset_in_page(tfm_input_data(clust));
+               src.length = tc->len;
+
+               dst.page = virt_to_page(tfm_output_data(clust));
+               dst.offset = offset_in_page(tfm_output_data(clust));
+               dst.length = tc->len;
+
+               result = crypto_blkcipher_encrypt(&desc, &dst, &src, tc->len);
+               if (result) {
+                       warning("edward-1405",
+                               "encryption failed flags=%x\n", desc.flags);
+                       return result;
+               }
+               encrypted = 1;
+       }
+       if (compressed && coplug->checksum != NULL)
+               dc_set_checksum(coplug, tc);
+       if (!compressed && !encrypted)
+               alternate_streams(tc);
+       return result;
+}
+
+/* Common inflate manager. */
+int reiser4_inflate_cluster(reiser4_cluster_t * clust, struct inode * inode)
+{
+       int result = 0;
+       int transformed = 0;
+       tfm_cluster_t * tc = &clust->tc;
+       compression_plugin * coplug;
+
+       assert("edward-905", inode != NULL);
+       assert("edward-1178", clust->dstat == PREP_DISK_CLUSTER);
+       assert("edward-906", tfm_stream_is_set(&clust->tc, INPUT_STREAM));
+       assert("edward-1349", tc->act == TFMA_READ);
+       assert("edward-907", !tfm_cluster_is_uptodate(tc));
+
+       /* Handle a checksum (if any) */
+       coplug = inode_compression_plugin(inode);
+       if (need_inflate(clust, inode, need_cipher(inode)) &&
+           coplug->checksum != NULL) {
+               result = dc_check_checksum(coplug, tc);
+               if (unlikely(result)) {
+                       warning("edward-1460",
+                               "Inode %llu: disk cluster %lu looks corrupted",
+                               (unsigned long long)get_inode_oid(inode),
+                               clust->index);
+                       return RETERR(-EIO);
+               }
+       }
+       if (need_cipher(inode)) {
+               cipher_plugin * ciplug;
+               struct blkcipher_desc desc;
+               struct scatterlist src;
+               struct scatterlist dst;
+
+               ciplug = inode_cipher_plugin(inode);
+               desc.tfm = info_get_cipher(inode_crypto_stat(inode));
+               desc.flags = 0;
+               result = grab_tfm_stream(inode, tc, OUTPUT_STREAM);
+               if (result)
+                       return result;
+               assert("edward-909", tfm_cluster_is_set(tc));
+
+               src.page   =   virt_to_page(tfm_input_data(clust));
+               src.offset = offset_in_page(tfm_input_data(clust));
+               src.length = tc->len;
+
+               dst.page   =   virt_to_page(tfm_output_data(clust));
+               dst.offset = offset_in_page(tfm_output_data(clust));
+               dst.length = tc->len;
+
+               result = crypto_blkcipher_decrypt(&desc, &dst, &src, tc->len);
+               if (result) {
+                       warning("edward-1600", "decrypt failed flags=%x\n",
+                               desc.flags);
+                       return result;
+               }
+               align_or_cut_overhead(inode, clust, READ_OP);
+               transformed = 1;
+       }
+       if (need_inflate(clust, inode, 0)) {
+               unsigned dst_len = inode_cluster_size(inode);
+               if(transformed)
+                       alternate_streams(tc);
+
+               result = grab_tfm_stream(inode, tc, OUTPUT_STREAM);
+               if (result)
+                       return result;
+               assert("edward-1305", coplug->decompress != NULL);
+               assert("edward-910", tfm_cluster_is_set(tc));
+
+               coplug->decompress(get_coa(tc, coplug->h.id, tc->act),
+                                  tfm_input_data(clust), tc->len,
+                                  tfm_output_data(clust), &dst_len);
+               /* check length */
+               tc->len = dst_len;
+               assert("edward-157", dst_len == tc->lsize);
+               transformed = 1;
+       }
+       if (!transformed)
+               alternate_streams(tc);
+       return result;
+}
+
+/* This is implementation of readpage method of struct
+   address_space_operations for cryptcompress plugin. */
+int readpage_cryptcompress(struct file *file, struct page *page)
+{
+       reiser4_context *ctx;
+       reiser4_cluster_t clust;
+       item_plugin *iplug;
+       int result;
+
+       assert("edward-88", PageLocked(page));
+       assert("vs-976", !PageUptodate(page));
+       assert("edward-89", page->mapping && page->mapping->host);
+
+       ctx = reiser4_init_context(page->mapping->host->i_sb);
+       if (IS_ERR(ctx)) {
+               unlock_page(page);
+               return PTR_ERR(ctx);
+       }
+       assert("edward-113",
+              ergo(file != NULL,
+                   page->mapping == file->f_dentry->d_inode->i_mapping));
+
+       if (PageUptodate(page)) {
+               warning("edward-1338", "page is already uptodate\n");
+               unlock_page(page);
+               reiser4_exit_context(ctx);
+               return 0;
+       }
+       cluster_init_read(&clust, NULL);
+       clust.file = file;
+       iplug = item_plugin_by_id(CTAIL_ID);
+       if (!iplug->s.file.readpage) {
+               unlock_page(page);
+               put_cluster_handle(&clust);
+               reiser4_exit_context(ctx);
+               return -EINVAL;
+       }
+       result = iplug->s.file.readpage(&clust, page);
+
+       assert("edward-1459", !PageLocked(page));
+       assert("edward-64", ergo(result == 0, PageUptodate(page)));
+       put_cluster_handle(&clust);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* how much pages will be captured */
+static int cluster_nrpages_to_capture(reiser4_cluster_t * clust)
+{
+       switch (clust->op) {
+       case PCL_APPEND:
+               return clust->nr_pages;
+       case PCL_TRUNCATE:
+               assert("edward-1179", clust->win != NULL);
+               return count_to_nrpages(clust->win->off + clust->win->count);
+       default:
+               impossible("edward-1180", "bad page cluster option");
+               return 0;
+       }
+}
+
+static void set_cluster_pages_dirty(reiser4_cluster_t * clust)
+{
+       int i;
+       struct page *pg;
+       int nrpages = cluster_nrpages_to_capture(clust);
+
+       for (i = 0; i < nrpages; i++) {
+
+               pg = clust->pages[i];
+               assert("edward-968", pg != NULL);
+               lock_page(pg);
+               assert("edward-1065", PageUptodate(pg));
+               reiser4_set_page_dirty_internal(pg);
+               unlock_page(pg);
+               mark_page_accessed(pg);
+       }
+}
+
+static void clear_cluster_pages_dirty(reiser4_cluster_t * clust)
+{
+       int i;
+       assert("edward-1275", clust != NULL);
+
+       for (i = 0; i < clust->nr_pages; i++) {
+               assert("edward-1276", clust->pages[i] != NULL);
+
+               lock_page(clust->pages[i]);
+               if (PageDirty(clust->pages[i])) {
+                       assert("edward-1277", PageUptodate(clust->pages[i]));
+                       cancel_dirty_page(clust->pages[i], PAGE_CACHE_SIZE);
+               }
+#if REISER4_DEBUG
+               else
+                       /* Race between flush and write:
+                          some pages became clean when write() (or another
+                          process which modifies data) capture the cluster. */
+                       warning("edward-985", "Page of index %lu (inode %llu)"
+                               " is not dirty\n", clust->pages[i]->index,
+                               (unsigned long long)get_inode_oid(clust->
+                                                                 pages[i]->
+                                                                 mapping->
+                                                                 host));
+#endif
+               unlock_page(clust->pages[i]);
+       }
+}
+
+/* update i_size by window */
+static void inode_set_new_size(reiser4_cluster_t * clust, struct inode *inode)
+{
+       loff_t size;
+       reiser4_slide_t *win;
+
+       assert("edward-1181", clust != NULL);
+       assert("edward-1182", inode != NULL);
+
+       win = clust->win;
+       assert("edward-1183", win != NULL);
+       assert("edward-1183", win->count != 0);
+
+       size = clust_to_off(clust->index, inode) + win->off;
+
+       switch (clust->op) {
+       case PCL_APPEND:
+               if (size + win->count <= inode->i_size)
+                       /* overwrite only */
+                       return;
+               size += win->count;
+               break;
+       case PCL_TRUNCATE:
+               break;
+       default:
+               impossible("edward-1184", "bad page cluster option");
+               break;
+       }
+       inode_check_scale_nolock(inode, inode->i_size, size);
+       inode->i_size = size;
+       return;
+}
+
+/* Check in page cluster modifications.
+   . Make jnode dirty, if it wasn't;
+   . Reserve space for a disk cluster update by flush algorithm, if needed;
+   . Clean up old references (if any).
+   . Put pages (grabbed in this thread) which will be truncated
+*/
+static void
+make_cluster_jnode_dirty_locked(reiser4_cluster_t * clust, jnode * node,
+                               loff_t * old_isize, struct inode *inode)
+{
+       int i;
+       int old_nrpages;
+       int new_nrpages = cluster_nrpages_to_capture(clust);
+
+       assert("edward-973", new_nrpages > 0);
+       assert("edward-221", node != NULL);
+       assert("edward-971", clust->reserved == 1);
+       assert_spin_locked(&(node->guard));
+       assert("edward-972", node->page_count <= cluster_nrpages(inode));
+       assert("edward-1263",
+              clust->reserved_prepped == estimate_update_cluster(inode));
+       assert("edward-1264", clust->reserved_unprepped == 0);
+
+       if (JF_ISSET(node, JNODE_DIRTY)) {
+               /* someone has modified this cluster, but
+                  the modifications are not committed yet */
+               old_nrpages =
+                       count_to_nrpages(cnt_to_clcnt(*old_isize,
+                                                     clust->index, inode));
+               /* free space which is already reserved */
+               free_reserved4cluster(inode, clust,
+                                     estimate_update_cluster(inode));
+               /* put old references */
+               for (i = 0; i < old_nrpages; i++) {
+                       assert("edward-975", clust->pages[i]);
+                       assert("edward-1185", PageUptodate(clust->pages[i]));
+
+                       page_cache_release(clust->pages[i]);
+#if REISER4_DEBUG
+                       cryptcompress_inode_data(inode)->pgcount --;
+#endif
+               }
+       } else {
+               /* no captured pages */
+               assert("edward-1043", node->page_count == 0);
+               jnode_make_dirty_locked(node);
+               clust->reserved = 0;
+       }
+       /* put pages that will be truncated (if any) */
+       for (i = new_nrpages; i < clust->nr_pages; i++) {
+               assert("edward-1433", clust->pages[i]);
+               assert("edward-1434", PageUptodate(clust->pages[i]));
+               page_cache_release(clust->pages[i]);
+#if REISER4_DEBUG
+               cryptcompress_inode_data(inode)->pgcount --;
+#endif
+       }
+#if REISER4_DEBUG
+       clust->reserved_prepped -= estimate_update_cluster(inode);
+       node->page_count = new_nrpages;
+#endif
+       return;
+}
+
+/* This function spawns a transaction and
+   is called by any thread as a final step in page cluster modification.
+*/
+static int try_capture_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       int result = 0;
+       loff_t old_size;
+       jnode *node;
+
+       assert("edward-1029", clust != NULL);
+       assert("edward-1030", clust->reserved == 1);
+       assert("edward-1031", clust->nr_pages != 0);
+       assert("edward-1032", clust->pages != NULL);
+       assert("edward-1033", clust->pages[0] != NULL);
+
+       node = jprivate(clust->pages[0]);
+       assert("edward-1035", node != NULL);
+       assert("edward-1446", jnode_is_cluster_page(node));
+
+       spin_lock_jnode(node);
+
+       old_size = inode->i_size;
+       if (clust->win)
+               inode_set_new_size(clust, inode);
+
+       result = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+       if (result)
+               goto exit;
+       make_cluster_jnode_dirty_locked(clust, node, &old_size, inode);
+      exit:
+       spin_unlock_jnode(node);
+       jput(node);
+       return result;
+}
+
+/* Collect unlocked cluster pages for any modifications and attach a jnode.
+   We allocate only one jnode per cluster, this jnode is binded to the first
+   page of this cluster, so we have an extra-reference that will exist with
+   this jnode, other references will be cleaned up in flush time.
+*/
+static int
+grab_cluster_pages_jnode(struct inode *inode, reiser4_cluster_t * clust)
+{
+       int i;
+       int result = 0;
+       jnode *node = NULL;
+
+       assert("edward-182", clust != NULL);
+       assert("edward-183", clust->pages != NULL);
+       assert("edward-184", clust->nr_pages <= cluster_nrpages(inode));
+
+       if (clust->nr_pages == 0)
+               return 0;
+
+       for (i = 0; i < clust->nr_pages; i++) {
+
+               assert("edward-1044", clust->pages[i] == NULL);
+
+               clust->pages[i] =
+                       find_or_create_page(inode->i_mapping,
+                                           clust_to_pg(clust->index, inode) + i,
+                                           reiser4_ctx_gfp_mask_get());
+               if (!clust->pages[i]) {
+                       result = RETERR(-ENOMEM);
+                       break;
+               }
+               if (i == 0) {
+                       node = jnode_of_page(clust->pages[i]);
+                       if (IS_ERR(node)) {
+                               result = PTR_ERR(node);
+                               unlock_page(clust->pages[i]);
+                               break;
+                       }
+                       JF_SET(node, JNODE_CLUSTER_PAGE);
+                       unlock_page(clust->pages[i]);
+                       assert("edward-919", node);
+                       continue;
+               }
+               unlock_page(clust->pages[i]);
+       }
+       if (result) {
+               while (i)
+                       page_cache_release(clust->pages[--i]);
+               if (node && !IS_ERR(node))
+                       jput(node);
+               return result;
+       }
+       assert("edward-920", jprivate(clust->pages[0]));
+#if REISER4_DEBUG
+       cryptcompress_inode_data(inode)->pgcount += clust->nr_pages;
+#endif
+       return 0;
+}
+
+/* Collect unlocked cluster pages only for read (not to modify) */
+int grab_cluster_pages(struct inode *inode, reiser4_cluster_t * clust)
+{
+       int i;
+       int result = 0;
+
+       assert("edward-1428", inode != NULL);
+       assert("edward-1429", inode->i_mapping != NULL);
+       assert("edward-787", clust != NULL);
+       assert("edward-788", clust->pages != NULL);
+       assert("edward-789", clust->nr_pages != 0);
+       assert("edward-790", clust->nr_pages <= cluster_nrpages(inode));
+
+       for (i = 0; i < clust->nr_pages; i++) {
+               clust->pages[i] =
+                      find_or_create_page(inode->i_mapping,
+                                          clust_to_pg(clust->index, inode) + i,
+                                          reiser4_ctx_gfp_mask_get());
+               if (!clust->pages[i]) {
+                       result = RETERR(-ENOMEM);
+                       break;
+               }
+               unlock_page(clust->pages[i]);
+       }
+       if (result)
+               while (i)
+                       page_cache_release(clust->pages[--i]);
+       return result;
+}
+
+/* @node might be attached by reiser4_writepage(), not by
+   cryptcompress plugin code, but emergency flush should
+   understand that pages of cryptcompress files are not
+   flushable.
+*/
+#if 0
+int jnode_of_cluster(const jnode * node, struct page * page)
+{
+       assert("edward-1339", node != NULL);
+       assert("edward-1340", page != NULL);
+       assert("edward-1341", page->mapping != NULL);
+       assert("edward-1342", page->mapping->host != NULL);
+       assert("edward-1343",
+              ergo(jnode_is_unformatted(node),
+                   get_inode_oid(page->mapping->host) ==
+                   node->key.j.objectid));
+       if (inode_file_plugin(page->mapping->host) ==
+           file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID)) {
+#if REISER4_DEBUG
+               if (!jnode_is_cluster_page(node))
+                       warning("edward-1345",
+                       "inode %llu: cluster page of index %lu became private",
+                       (unsigned long long)get_inode_oid(page->mapping->host),
+                       page->index);
+#endif
+               return 1;
+       }
+       return 0;
+}
+#endif  /*  0  */
+
+/* put cluster pages */
+void reiser4_release_cluster_pages(reiser4_cluster_t * clust)
+{
+       int i;
+
+       assert("edward-447", clust != NULL);
+       for (i = 0; i < clust->nr_pages; i++) {
+
+               assert("edward-449", clust->pages[i] != NULL);
+
+               page_cache_release(clust->pages[i]);
+       }
+}
+
+/* this is called when something is failed */
+static void reiser4_release_cluster_pages_and_jnode(reiser4_cluster_t * clust)
+{
+       jnode *node;
+
+       assert("edward-445", clust != NULL);
+       assert("edward-922", clust->pages != NULL);
+       assert("edward-446", clust->pages[0] != NULL);
+
+       node = jprivate(clust->pages[0]);
+
+       assert("edward-447", node != NULL);
+
+       reiser4_release_cluster_pages(clust);
+       jput(node);
+}
+
+#if REISER4_DEBUG
+static int window_ok(reiser4_slide_t * win, struct inode *inode)
+{
+       assert("edward-1115", win != NULL);
+       assert("edward-1116", ergo(win->delta, win->stat == HOLE_WINDOW));
+
+       return (win->off != inode_cluster_size(inode)) &&
+           (win->off + win->count + win->delta <= inode_cluster_size(inode));
+}
+
+static int cluster_ok(reiser4_cluster_t * clust, struct inode *inode)
+{
+       assert("edward-279", clust != NULL);
+
+       if (!clust->pages)
+               return 0;
+       return (clust->win ? window_ok(clust->win, inode) : 1);
+}
+#endif
+
+/* guess next window stat */
+static inline window_stat next_window_stat(reiser4_slide_t * win)
+{
+       assert("edward-1130", win != NULL);
+       return ((win->stat == HOLE_WINDOW && win->delta == 0) ?
+               HOLE_WINDOW : DATA_WINDOW);
+}
+
+/* guess next cluster index and window params */
+static void
+update_cluster(struct inode *inode, reiser4_cluster_t * clust, loff_t file_off,
+              loff_t to_file)
+{
+       reiser4_slide_t *win;
+
+       assert("edward-185", clust != NULL);
+       assert("edward-438", clust->pages != NULL);
+       assert("edward-281", cluster_ok(clust, inode));
+
+       win = clust->win;
+       if (!win)
+               return;
+
+       switch (win->stat) {
+       case DATA_WINDOW:
+               /* increment window position */
+               clust->index++;
+               win->stat = DATA_WINDOW;
+               win->off = 0;
+               win->count = min_count(inode_cluster_size(inode), to_file);
+               break;
+       case HOLE_WINDOW:
+               switch (next_window_stat(win)) {
+               case HOLE_WINDOW:
+                       /* set window to fit the offset we start write from */
+                       clust->index = off_to_clust(file_off, inode);
+                       win->stat = HOLE_WINDOW;
+                       win->off = 0;
+                       win->count = off_to_cloff(file_off, inode);
+                       win->delta =
+                           min_count(inode_cluster_size(inode) - win->count,
+                                     to_file);
+                       break;
+               case DATA_WINDOW:
+                       /* do not move the window, just change its state,
+                          off+count+delta=inv */
+                       win->stat = DATA_WINDOW;
+                       win->off = win->off + win->count;
+                       win->count = win->delta;
+                       win->delta = 0;
+                       break;
+               default:
+                       impossible("edward-282", "wrong next window state");
+               }
+               break;
+       default:
+               impossible("edward-283", "wrong current window state");
+       }
+       assert("edward-1068", cluster_ok(clust, inode));
+}
+
+static int update_sd_cryptcompress(struct inode *inode)
+{
+       int result = 0;
+
+       assert("edward-978", reiser4_schedulable());
+
+       result = reiser4_grab_space_force(      /* one for stat data update */
+                                                estimate_update_common(inode),
+                                                BA_CAN_COMMIT);
+       if (result)
+               return result;
+       inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+       result = reiser4_update_sd(inode);
+
+       return result;
+}
+
+/* NOTE-Edward: this is too similar to reiser4/txnmgr.c:uncapture_jnode() */
+static void uncapture_cluster_jnode(jnode * node)
+{
+       txn_atom *atom;
+
+       assert_spin_locked(&(node->guard));
+
+       /*jnode_make_clean(node); */
+       atom = jnode_get_atom(node);
+       if (atom == NULL) {
+               assert("jmacd-7111", !JF_ISSET(node, JNODE_DIRTY));
+               spin_unlock_jnode(node);
+               return;
+       }
+
+       reiser4_uncapture_block(node);
+       spin_unlock_atom(atom);
+       jput(node);
+}
+
+static void forget_cluster_pages(struct page **pages, int nr)
+{
+       int i;
+       for (i = 0; i < nr; i++) {
+
+               assert("edward-1045", pages[i] != NULL);
+               page_cache_release(pages[i]);
+       }
+}
+
+/* Check out last modifications we are about to commit,
+   and prepare input stream for transform operations.
+*/
+int
+flush_cluster_pages(reiser4_cluster_t * clust, jnode * node,
+                   struct inode *inode)
+{
+       int result = 0;
+       int i;
+       int nr_pages = 0;
+       tfm_cluster_t *tc = &clust->tc;
+#if REISER4_DEBUG
+       int node_pgcount;
+#endif
+       assert("edward-980", node != NULL);
+       assert("edward-236", inode != NULL);
+       assert("edward-237", clust != NULL);
+       assert("edward-240", !clust->win);
+       assert("edward-241", reiser4_schedulable());
+       assert("edward-718", cryptcompress_inode_ok(inode));
+
+       result = grab_tfm_stream(inode, tc, INPUT_STREAM);
+       if (result) {
+               warning("edward-1430",
+                       "alloc stream failed with ret=%d", result);
+               return result;
+       }
+       spin_lock_jnode(node);
+#if REISER4_DEBUG
+       node_pgcount = node->page_count;
+#endif
+       if (!JF_ISSET(node, JNODE_DIRTY)) {
+               /* race with another flush */
+#if REISER4_DEBUG
+               assert("edward-981", node_pgcount == 0);
+               warning("edward-982", "flush_cluster_pages: jnode is not dirty "
+                       "clust %lu, inode %llu\n",
+                       clust->index, (unsigned long long)get_inode_oid(inode));
+#endif
+               spin_unlock_jnode(node);
+               return RETERR(-E_REPEAT);
+       }
+       /* Check out a size of logical cluster and
+          set a number of cluster pages to commit. */
+       tc->len = tc->lsize = fsize_to_count(clust, inode);
+       clust->nr_pages = count_to_nrpages(tc->len);
+
+#if REISER4_DEBUG
+       node->page_count = 0;
+#endif
+       cluster_reserved2grabbed(estimate_update_cluster(inode));
+       uncapture_cluster_jnode(node);
+
+       assert("edward-1224", reiser4_schedulable());
+       /* Check out page cluster for commit */
+       nr_pages =
+             find_get_pages(inode->i_mapping, clust_to_pg(clust->index, inode),
+                            clust->nr_pages, clust->pages);
+       if (nr_pages != clust->nr_pages)
+               goto checkout_failed;
+
+       /* Try to construct input stream from the checked out pages */
+       for (i = 0; i < clust->nr_pages; i++) {
+               char *data;
+
+               assert("edward-242", clust->pages[i] != NULL);
+               if (clust->pages[i]->index !=
+                   clust_to_pg(clust->index, inode) + i)
+                       goto checkout_failed;
+               BUG_ON(!PageUptodate(clust->pages[i]));
+
+               /* flush the page into input transform stream */
+               lock_page(clust->pages[i]);
+               data = kmap(clust->pages[i]);
+
+               assert("edward-986", cnt_to_pgcnt(tc->len, i) != 0);
+
+               memcpy(tfm_stream_data(tc, INPUT_STREAM) + pg_to_off(i),
+                      data, cnt_to_pgcnt(tc->len, i));
+               kunmap(clust->pages[i]);
+               unlock_page(clust->pages[i]);
+       }
+       /* page cluster flushed successfully */
+
+       clear_cluster_pages_dirty(clust);
+       reiser4_release_cluster_pages(clust);
+#if REISER4_DEBUG
+       cryptcompress_inode_data(inode)->pgcount -= clust->nr_pages;
+#endif
+       goto out;
+ checkout_failed:
+#if REISER4_DEBUG
+       assert("edward-1282", node_pgcount == 0);
+       warning("edward-1435", "Inode %llu : checkout page cluster"
+               "of index %lu failed\n",
+                       (unsigned long long)get_inode_oid(inode), clust->index);
+#endif /* REISER4_DEBUG */
+       result = RETERR(-E_REPEAT);
+ out:
+       /* put pages that were found here */
+       forget_cluster_pages(clust->pages, nr_pages);
+       return result;
+}
+
+/* set hint for the cluster of the index @index */
+static void set_hint_cluster(struct inode *inode, hint_t * hint,
+                            cloff_t index, znode_lock_mode mode)
+{
+       reiser4_key key;
+       assert("edward-722", cryptcompress_inode_ok(inode));
+       assert("edward-723",
+              inode_file_plugin(inode) ==
+              file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID));
+
+       inode_file_plugin(inode)->key_by_inode(inode,
+                                              clust_to_off(index, inode),
+                                              &key);
+
+       reiser4_seal_init(&hint->seal, &hint->ext_coord.coord, &key);
+       hint->offset = get_key_offset(&key);
+       hint->mode = mode;
+}
+
+void invalidate_hint_cluster(reiser4_cluster_t * clust)
+{
+       assert("edward-1291", clust != NULL);
+       assert("edward-1292", clust->hint != NULL);
+
+       done_lh(&clust->hint->lh);
+       hint_clr_valid(clust->hint);
+}
+
+void put_hint_cluster(reiser4_cluster_t * clust, struct inode *inode,
+                znode_lock_mode mode)
+{
+       assert("edward-1286", clust != NULL);
+       assert("edward-1287", clust->hint != NULL);
+
+       set_hint_cluster(inode, clust->hint, clust->index + 1, mode);
+       invalidate_hint_cluster(clust);
+}
+
+static int
+balance_dirty_page_cluster(reiser4_cluster_t * clust, struct inode *inode,
+                          loff_t off, loff_t to_file)
+{
+       int result;
+
+       assert("edward-724", inode != NULL);
+       assert("edward-725", cryptcompress_inode_ok(inode));
+
+       /* set next window params */
+       update_cluster(inode, clust, off, to_file);
+
+       result = update_sd_cryptcompress(inode);
+       if (result)
+               return result;
+       assert("edward-726", clust->hint->lh.owner == NULL);
+
+       reiser4_throttle_write(inode);
+       return 0;
+}
+
+/* set zeroes to the cluster, update it, and maybe, try to capture its pages */
+static int
+write_hole(struct inode *inode, reiser4_cluster_t * clust, loff_t file_off,
+          loff_t to_file)
+{
+       char *data;
+       int result = 0;
+       unsigned cl_off, cl_count = 0;
+       unsigned to_pg, pg_off;
+       reiser4_slide_t *win;
+
+       assert("edward-190", clust != NULL);
+       assert("edward-1069", clust->win != NULL);
+       assert("edward-191", inode != NULL);
+       assert("edward-727", cryptcompress_inode_ok(inode));
+       assert("edward-1171", clust->dstat != INVAL_DISK_CLUSTER);
+       assert("edward-1154",
+              ergo(clust->dstat != FAKE_DISK_CLUSTER, clust->reserved == 1));
+
+       win = clust->win;
+
+       assert("edward-1070", win != NULL);
+       assert("edward-201", win->stat == HOLE_WINDOW);
+       assert("edward-192", cluster_ok(clust, inode));
+
+       if (win->off == 0 && win->count == inode_cluster_size(inode)) {
+               /* the hole will be represented by fake disk cluster */
+               update_cluster(inode, clust, file_off, to_file);
+               return 0;
+       }
+       cl_count = win->count;  /* number of zeroes to write */
+       cl_off = win->off;
+       pg_off = off_to_pgoff(win->off);
+
+       while (cl_count) {
+               struct page *page;
+               page = clust->pages[off_to_pg(cl_off)];
+
+               assert("edward-284", page != NULL);
+
+               to_pg = min_count(PAGE_CACHE_SIZE - pg_off, cl_count);
+               lock_page(page);
+               data = kmap_atomic(page, KM_USER0);
+               memset(data + pg_off, 0, to_pg);
+               flush_dcache_page(page);
+               kunmap_atomic(data, KM_USER0);
+               SetPageUptodate(page);
+               unlock_page(page);
+
+               cl_off += to_pg;
+               cl_count -= to_pg;
+               pg_off = 0;
+       }
+       if (!win->delta) {
+               /* only zeroes, try to capture */
+
+               set_cluster_pages_dirty(clust);
+               result = try_capture_cluster(clust, inode);
+               if (result)
+                       return result;
+               put_hint_cluster(clust, inode, ZNODE_WRITE_LOCK);
+               result =
+                   balance_dirty_page_cluster(clust, inode, file_off, to_file);
+       } else
+               update_cluster(inode, clust, file_off, to_file);
+       return result;
+}
+
+/*
+  The main disk search procedure for cryptcompress plugins, which
+  . scans all items of disk cluster with the lock mode @mode
+  . maybe reads each one (if @read)
+  . maybe makes its znode dirty (if write lock mode was specified)
+
+  NOTE-EDWARD: Callers should handle the case when disk cluster
+  is incomplete (-EIO)
+*/
+int find_disk_cluster(reiser4_cluster_t * clust,
+                     struct inode *inode, int read, znode_lock_mode mode)
+{
+       flow_t f;
+       hint_t *hint;
+       int result = 0;
+       unsigned long cl_idx;
+       ra_info_t ra_info;
+       file_plugin *fplug;
+       item_plugin *iplug;
+       tfm_cluster_t *tc;
+       int was_grabbed;
+
+       assert("edward-138", clust != NULL);
+       assert("edward-728", clust->hint != NULL);
+       assert("edward-226", reiser4_schedulable());
+       assert("edward-137", inode != NULL);
+       assert("edward-729", cryptcompress_inode_ok(inode));
+
+       hint = clust->hint;
+       cl_idx = clust->index;
+       fplug = inode_file_plugin(inode);
+       was_grabbed = get_current_context()->grabbed_blocks;
+       tc = &clust->tc;
+
+       assert("edward-462", !tfm_cluster_is_uptodate(tc));
+       assert("edward-461", ergo(read, tfm_stream_is_set(tc, INPUT_STREAM)));
+
+       dclust_init_extension(hint);
+
+       /* set key of the first disk cluster item */
+       fplug->flow_by_inode(inode,
+                            (read ? (char __user *)tfm_stream_data(tc, INPUT_STREAM) : NULL),
+                            0 /* kernel space */ ,
+                            inode_scaled_cluster_size(inode),
+                            clust_to_off(cl_idx, inode), READ_OP, &f);
+       if (mode == ZNODE_WRITE_LOCK) {
+               /* reserve for flush to make dirty all the leaf nodes
+                  which contain disk cluster */
+               result =
+                   reiser4_grab_space_force(estimate_dirty_cluster(inode),
+                                            BA_CAN_COMMIT);
+               if (result)
+                       goto out;
+       }
+
+       ra_info.key_to_stop = f.key;
+       set_key_offset(&ra_info.key_to_stop, get_key_offset(reiser4_max_key()));
+
+       while (f.length) {
+               result = find_cluster_item(hint, &f.key, mode,
+                                          NULL, FIND_EXACT,
+                                          (mode == ZNODE_WRITE_LOCK ?
+                                           CBK_FOR_INSERT : 0));
+               switch (result) {
+               case CBK_COORD_NOTFOUND:
+                       result = 0;
+                       if (inode_scaled_offset
+                           (inode,
+                            clust_to_off(cl_idx,
+                                         inode)) == get_key_offset(&f.key)) {
+                               /* first item not found, this is treated
+                                  as disk cluster is absent */
+                               clust->dstat = FAKE_DISK_CLUSTER;
+                               goto out;
+                       }
+                       /* we are outside the cluster, stop search here */
+                       assert("edward-146",
+                              f.length != inode_scaled_cluster_size(inode));
+                       goto ok;
+               case CBK_COORD_FOUND:
+                       assert("edward-148",
+                              hint->ext_coord.coord.between == AT_UNIT);
+                       assert("edward-460",
+                              hint->ext_coord.coord.unit_pos == 0);
+
+                       coord_clear_iplug(&hint->ext_coord.coord);
+                       result = zload_ra(hint->ext_coord.coord.node, &ra_info);
+                       if (unlikely(result))
+                               goto out;
+                       iplug = item_plugin_by_coord(&hint->ext_coord.coord);
+                       assert("edward-147",
+                              item_id_by_coord(&hint->ext_coord.coord) ==
+                              CTAIL_ID);
+
+                       result = iplug->s.file.read(NULL, &f, hint);
+                       if (result) {
+                               zrelse(hint->ext_coord.coord.node);
+                               goto out;
+                       }
+                       if (mode == ZNODE_WRITE_LOCK) {
+                               /* Don't make dirty more nodes then it was
+                                  estimated (see comments before
+                                  estimate_dirty_cluster). Missed nodes will be
+                                  read up in flush time if they are evicted from
+                                  memory */
+                               if (dclust_get_extension_ncount(hint) <=
+                                   estimate_dirty_cluster(inode))
+                                  znode_make_dirty(hint->ext_coord.coord.node);
+
+                               znode_set_convertible(hint->ext_coord.coord.
+                                                     node);
+                       }
+                       zrelse(hint->ext_coord.coord.node);
+                       break;
+               default:
+                       goto out;
+               }
+       }
+ ok:
+       /* at least one item was found  */
+       /* NOTE-EDWARD: Callers should handle the case
+          when disk cluster is incomplete (-EIO) */
+       tc->len = inode_scaled_cluster_size(inode) - f.length;
+       tc->lsize = fsize_to_count(clust, inode);
+       assert("edward-1196", tc->len > 0);
+       assert("edward-1406", tc->lsize > 0);
+
+       if (hint_is_unprepped_dclust(clust->hint))
+               clust->dstat = UNPR_DISK_CLUSTER;
+       else {
+               dclust_set_extension_dsize(clust->hint, tc->len);
+               clust->dstat = PREP_DISK_CLUSTER;
+       }
+ out:
+       assert("edward-1339",
+              get_current_context()->grabbed_blocks >= was_grabbed);
+       grabbed2free(get_current_context(),
+                    get_current_super_private(),
+                    get_current_context()->grabbed_blocks - was_grabbed);
+       return result;
+}
+
+int
+get_disk_cluster_locked(reiser4_cluster_t * clust, struct inode *inode,
+                       znode_lock_mode lock_mode)
+{
+       reiser4_key key;
+       ra_info_t ra_info;
+
+       assert("edward-730", reiser4_schedulable());
+       assert("edward-731", clust != NULL);
+       assert("edward-732", inode != NULL);
+
+       if (hint_is_valid(clust->hint)) {
+               assert("edward-1293", clust->dstat != INVAL_DISK_CLUSTER);
+               assert("edward-1294",
+                      znode_is_write_locked(clust->hint->lh.node));
+               /* already have a valid locked position */
+               return (clust->dstat ==
+                       FAKE_DISK_CLUSTER ? CBK_COORD_NOTFOUND :
+                       CBK_COORD_FOUND);
+       }
+       key_by_inode_cryptcompress(inode, clust_to_off(clust->index, inode),
+                                  &key);
+       ra_info.key_to_stop = key;
+       set_key_offset(&ra_info.key_to_stop, get_key_offset(reiser4_max_key()));
+
+       return find_cluster_item(clust->hint, &key, lock_mode, NULL, FIND_EXACT,
+                                CBK_FOR_INSERT);
+}
+
+/* Read needed cluster pages before modifying.
+   If success, @clust->hint contains locked position in the tree.
+   Also:
+   . find and set disk cluster state
+   . make disk cluster dirty if its state is not FAKE_DISK_CLUSTER.
+*/
+static int
+read_some_cluster_pages(struct inode *inode, reiser4_cluster_t * clust)
+{
+       int i;
+       int result = 0;
+       item_plugin *iplug;
+       reiser4_slide_t *win = clust->win;
+       znode_lock_mode mode = ZNODE_WRITE_LOCK;
+
+       iplug = item_plugin_by_id(CTAIL_ID);
+
+       assert("edward-924", !tfm_cluster_is_uptodate(&clust->tc));
+
+#if REISER4_DEBUG
+       if (clust->nr_pages == 0) {
+               /* start write hole from fake disk cluster */
+               assert("edward-1117", win != NULL);
+               assert("edward-1118", win->stat == HOLE_WINDOW);
+               assert("edward-1119", new_cluster(clust, inode));
+       }
+#endif
+       if (new_cluster(clust, inode)) {
+               /*
+                  new page cluster is about to be written, nothing to read,
+                */
+               assert("edward-734", reiser4_schedulable());
+               assert("edward-735", clust->hint->lh.owner == NULL);
+
+               if (clust->nr_pages) {
+                       int off;
+                       char *data;
+                       struct page * pg;
+                       assert("edward-1419", clust->pages != NULL);
+                       pg = clust->pages[clust->nr_pages - 1];
+                       assert("edward-1420", pg != NULL);
+                       off = off_to_pgoff(win->off+win->count+win->delta);
+                       if (off) {
+                               lock_page(pg);
+                               data = kmap_atomic(pg, KM_USER0);
+                               memset(data + off, 0, PAGE_CACHE_SIZE - off);
+                               flush_dcache_page(pg);
+                               kunmap_atomic(data, KM_USER0);
+                               unlock_page(pg);
+                       }
+               }
+               clust->dstat = FAKE_DISK_CLUSTER;
+               return 0;
+       }
+       /*
+          Here we should search for disk cluster to figure out its real state.
+          Also there is one more important reason to do disk search: we need
+          to make disk cluster _dirty_ if it exists
+        */
+
+       /* if windows is specified, read the only pages
+          that will be modified partially */
+
+       for (i = 0; i < clust->nr_pages; i++) {
+               struct page *pg = clust->pages[i];
+
+               lock_page(pg);
+               if (PageUptodate(pg)) {
+                       unlock_page(pg);
+                       continue;
+               }
+               unlock_page(pg);
+
+               if (win &&
+                   i >= count_to_nrpages(win->off) &&
+                   i < off_to_pg(win->off + win->count + win->delta))
+                       /* page will be completely overwritten */
+                       continue;
+
+               if (win && (i == clust->nr_pages - 1) &&
+                   /* the last page is
+                      partially modified,
+                      not uptodate .. */
+                   (count_to_nrpages(inode->i_size) <= pg->index)) {
+                       /* .. and appended,
+                          so set zeroes to the rest */
+                       char *data;
+                       int offset;
+                       lock_page(pg);
+                       data = kmap_atomic(pg, KM_USER0);
+
+                       assert("edward-1260",
+                              count_to_nrpages(win->off + win->count +
+                                               win->delta) - 1 == i);
+
+                       offset =
+                           off_to_pgoff(win->off + win->count + win->delta);
+                       memset(data + offset, 0, PAGE_CACHE_SIZE - offset);
+                       flush_dcache_page(pg);
+                       kunmap_atomic(data, KM_USER0);
+                       unlock_page(pg);
+                       /* still not uptodate */
+                       break;
+               }
+               if (!tfm_cluster_is_uptodate(&clust->tc)) {
+                       result = ctail_read_disk_cluster(clust, inode, mode);
+                       if (result)
+                               goto out;
+                       assert("edward-925",
+                              tfm_cluster_is_uptodate(&clust->tc));
+               }
+               lock_page(pg);
+               result = do_readpage_ctail(inode, clust, pg, mode);
+               unlock_page(pg);
+               if (result) {
+                       impossible("edward-219",
+                                  "do_readpage_ctail returned crap");
+                       goto out;
+               }
+       }
+       if (!tfm_cluster_is_uptodate(&clust->tc)) {
+               /* disk cluster unclaimed, but we need to make its znodes dirty
+                  to make flush update convert its content */
+               result = find_disk_cluster(clust, inode, 0 /* do not read items */,
+                                          mode);
+       }
+ out:
+       tfm_cluster_clr_uptodate(&clust->tc);
+       return result;
+}
+
+static int
+should_create_unprepped_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       assert("edward-737", clust != NULL);
+
+       switch (clust->dstat) {
+       case PREP_DISK_CLUSTER:
+       case UNPR_DISK_CLUSTER:
+               return 0;
+       case FAKE_DISK_CLUSTER:
+               if (clust->win &&
+                   clust->win->stat == HOLE_WINDOW && clust->nr_pages == 0) {
+                       assert("edward-1172", new_cluster(clust, inode));
+                       return 0;
+               }
+               return 1;
+       default:
+               impossible("edward-1173", "bad disk cluster state");
+               return 0;
+       }
+}
+
+static int
+cryptcompress_make_unprepped_cluster(reiser4_cluster_t * clust,
+                                    struct inode *inode)
+{
+       int result;
+
+       assert("edward-1123", reiser4_schedulable());
+       assert("edward-737", clust != NULL);
+       assert("edward-738", inode != NULL);
+       assert("edward-739", cryptcompress_inode_ok(inode));
+       assert("edward-1053", clust->hint != NULL);
+
+       if (!should_create_unprepped_cluster(clust, inode)) {
+               if (clust->reserved) {
+                       cluster_reserved2free(estimate_insert_cluster(inode));
+#if REISER4_DEBUG
+                       assert("edward-1267",
+                              clust->reserved_unprepped ==
+                              estimate_insert_cluster(inode));
+                       clust->reserved_unprepped -=
+                               estimate_insert_cluster(inode);
+#endif
+               }
+               return 0;
+       }
+       assert("edward-1268", clust->reserved);
+       cluster_reserved2grabbed(estimate_insert_cluster(inode));
+#if REISER4_DEBUG
+       assert("edward-1441",
+              clust->reserved_unprepped == estimate_insert_cluster(inode));
+       clust->reserved_unprepped -= estimate_insert_cluster(inode);
+#endif
+       result = ctail_insert_unprepped_cluster(clust, inode);
+       if (result)
+               return result;
+
+       inode_add_bytes(inode, inode_cluster_size(inode));
+
+       assert("edward-743", cryptcompress_inode_ok(inode));
+       assert("edward-744", znode_is_write_locked(clust->hint->lh.node));
+
+       clust->dstat = UNPR_DISK_CLUSTER;
+       return 0;
+}
+
+#if REISER4_DEBUG
+static int jnode_truncate_ok(struct inode *inode, cloff_t index)
+{
+       jnode *node;
+       node =
+           jlookup(current_tree, get_inode_oid(inode),
+                   clust_to_pg(index, inode));
+       if (likely(!node))
+               return 1;
+       /* someone got this jnode */
+       warning("edward-1315", "jnode %p is untruncated\n", node);
+       jput(node);
+       return (atomic_read(&node->x_count));
+}
+#endif
+
+/* Collect unlocked cluster pages and jnode (the last is in the
+   case when the page cluster will be modified and captured) */
+int
+prepare_page_cluster(struct inode *inode, reiser4_cluster_t * clust,
+                    int capture)
+{
+       assert("edward-177", inode != NULL);
+       assert("edward-741", cryptcompress_inode_ok(inode));
+       assert("edward-740", clust->pages != NULL);
+
+       set_cluster_nrpages(clust, inode);
+       reset_cluster_pgset(clust, cluster_nrpages(inode));
+       return (capture ?
+               grab_cluster_pages_jnode(inode, clust) :
+               grab_cluster_pages(inode, clust));
+}
+
+/* Truncate all pages of the cluster of index @index.
+   This is called by ->kill_hook() method of item plugin */
+void truncate_page_cluster_cryptcompress(struct inode *inode, cloff_t index,
+                                        int even_cows)
+{
+       int i;
+       int found = 0;
+       int nr_pages;
+       jnode *node;
+       struct page *pages[MAX_CLUSTER_NRPAGES];
+
+       node =
+           jlookup(current_tree, get_inode_oid(inode),
+                   clust_to_pg(index, inode));
+       /* jnode is absent, just drop pages which can not
+          acquire jnode because of exclusive access */
+       if (!node)
+               goto truncate;
+       /* jnode is present and may be dirty */
+       nr_pages = count_to_nrpages(cnt_to_clcnt(inode->i_size, index, inode));
+
+       found = find_get_pages(inode->i_mapping, clust_to_pg(index, inode),
+                              nr_pages, pages);
+       spin_lock_jnode(node);
+
+       if (reiser4_inode_get_flag(inode, REISER4_FILE_CONV_IN_PROGRESS)
+           && index == 0)
+               /* converting to unix_file in progress */
+               JF_CLR(node, JNODE_CLUSTER_PAGE);
+       if (JF_ISSET(node, JNODE_DIRTY)) {
+               /* someone has done modifications which are not
+                  yet committed, so we need to release some resources */
+
+               /* free disk space grabbed for disk cluster converting */
+               cluster_reserved2grabbed(estimate_update_cluster(inode));
+               grabbed2free(get_current_context(),
+                            get_current_super_private(),
+                            estimate_update_cluster(inode));
+
+               assert("edward-1198", found == nr_pages);
+               assert("edward-1199", node->page_count == nr_pages);
+#if REISER4_DEBUG
+               node->page_count = 0;
+#endif
+               /* This will clear dirty bit */
+               uncapture_cluster_jnode(node);
+
+               /* put pages grabbed for last uncommitted modifications */
+               for (i = 0; i < nr_pages; i++) {
+                       assert("edward-1200", PageUptodate(pages[i]));
+                       page_cache_release(pages[i]);
+#if REISER4_DEBUG
+                       cryptcompress_inode_data(inode)->pgcount --;
+#endif
+               }
+       } else
+               spin_unlock_jnode(node);
+       /* FIXME-EDWARD: Use truncate_complete_page in the loop above instead */
+
+       jput(node);
+       /* put pages found here */
+       forget_cluster_pages(pages, found);
+ truncate:
+       if (reiser4_inode_get_flag(inode, REISER4_FILE_CONV_IN_PROGRESS) &&
+           index == 0)
+               return;
+       reiser4_invalidate_pages(inode->i_mapping,
+                                clust_to_pg(index, inode),
+                                cluster_nrpages(inode),
+                                even_cows);
+       assert("edward-1201",
+              ergo(!reiser4_inode_get_flag(inode,
+                                           REISER4_FILE_CONV_IN_PROGRESS),
+                   jnode_truncate_ok(inode, index)));
+       return;
+}
+
+/* Prepare cluster handle before(after) modifications
+   which are supposed to be committed.
+
+   . grab cluster pages;
+   . reserve disk space;
+   . maybe read pages from disk and set the disk cluster dirty;
+   . maybe write hole;
+   . maybe create 'unprepped' disk cluster if the last one is fake
+     (i.e. is not represenred by any items)
+*/
+
+static int
+prepare_cluster(struct inode *inode,
+               loff_t file_off /* write position in the file */ ,
+               loff_t to_file, /* bytes of users data to write to the file */
+               reiser4_cluster_t * clust, page_cluster_op op)
+{
+       int result = 0;
+       reiser4_slide_t *win = clust->win;
+
+       reset_cluster_params(clust);
+       cluster_set_tfm_act(&clust->tc, TFMA_READ);
+#if REISER4_DEBUG
+       clust->ctx = get_current_context();
+#endif
+       assert("edward-1190", op != PCL_UNKNOWN);
+
+       clust->op = op;
+
+       result = prepare_page_cluster(inode, clust, 1);
+       if (result)
+               return result;
+       assert("edward-1447",
+              ergo(clust->nr_pages != 0, jprivate(clust->pages[0])));
+       assert("edward-1448",
+              ergo(clust->nr_pages != 0,
+                   jnode_is_cluster_page(jprivate(clust->pages[0]))));
+
+       result = reserve4cluster(inode, clust);
+       if (result)
+               goto err1;
+       result = read_some_cluster_pages(inode, clust);
+       if (result) {
+               free_reserved4cluster(inode,
+                                     clust,
+                                     estimate_update_cluster(inode) +
+                                     estimate_insert_cluster(inode));
+               goto err1;
+       }
+       assert("edward-1124", clust->dstat != INVAL_DISK_CLUSTER);
+
+       result = cryptcompress_make_unprepped_cluster(clust, inode);
+       if (result)
+               goto err2;
+       if (win && win->stat == HOLE_WINDOW) {
+               result = write_hole(inode, clust, file_off, to_file);
+               if (result)
+                       goto err2;
+       }
+       return 0;
+      err2:
+       free_reserved4cluster(inode, clust,
+                             estimate_update_cluster(inode));
+      err1:
+       reiser4_release_cluster_pages_and_jnode(clust);
+       assert("edward-1125", result == -ENOSPC);
+       return result;
+}
+
+/* set window by two offsets */
+static void
+set_window(reiser4_cluster_t * clust, reiser4_slide_t * win,
+          struct inode *inode, loff_t o1, loff_t o2)
+{
+       assert("edward-295", clust != NULL);
+       assert("edward-296", inode != NULL);
+       assert("edward-1071", win != NULL);
+       assert("edward-297", o1 <= o2);
+
+       clust->index = off_to_clust(o1, inode);
+
+       win->off = off_to_cloff(o1, inode);
+       win->count = min_count(inode_cluster_size(inode) - win->off, o2 - o1);
+       win->delta = 0;
+
+       clust->win = win;
+}
+
+static int
+set_cluster_by_window(struct inode *inode, reiser4_cluster_t * clust,
+                     reiser4_slide_t * win, flow_t * f, loff_t file_off)
+{
+       int result;
+
+       assert("edward-197", clust != NULL);
+       assert("edward-1072", win != NULL);
+       assert("edward-198", inode != NULL);
+
+       result = alloc_cluster_pgset(clust, cluster_nrpages(inode));
+       if (result)
+               return result;
+
+       if (file_off > inode->i_size) {
+               /* Uhmm, hole in cryptcompress file... */
+               loff_t hole_size;
+               hole_size = file_off - inode->i_size;
+
+               set_window(clust, win, inode, inode->i_size, file_off);
+               win->stat = HOLE_WINDOW;
+               if (win->off + hole_size < inode_cluster_size(inode))
+                       /* there is also user's data to append to the hole */
+                       win->delta =
+                           min_count(inode_cluster_size(inode) -
+                                     (win->off + win->count), f->length);
+               return 0;
+       }
+       set_window(clust, win, inode, file_off, file_off + f->length);
+       win->stat = DATA_WINDOW;
+       return 0;
+}
+
+int set_cluster_by_page(reiser4_cluster_t * clust, struct page * page,
+                       int count)
+{
+       int result = 0;
+       int (*setting_actor)(reiser4_cluster_t * clust, int count);
+
+       assert("edward-1358", clust != NULL);
+       assert("edward-1359", page != NULL);
+       assert("edward-1360", page->mapping != NULL);
+       assert("edward-1361", page->mapping->host != NULL);
+
+       setting_actor  = (clust->pages ? reset_cluster_pgset : alloc_cluster_pgset);
+       result = setting_actor(clust, count);
+       clust->index = pg_to_clust(page->index, page->mapping->host);
+       return result;
+}
+
+/* reset all the params that not get updated */
+void reset_cluster_params(reiser4_cluster_t * clust)
+{
+       assert("edward-197", clust != NULL);
+
+       clust->dstat = INVAL_DISK_CLUSTER;
+       clust->tc.uptodate = 0;
+       clust->tc.len = 0;
+}
+
+/* Core write procedure of cryptcompress plugin, which slices user's
+   flow into logical clusters, maps the last ones to the appropriate
+   page clusters, and tries to capture them.
+   If @buf != NULL, returns number of successfully written bytes,
+   otherwise returns error
+*/
+static loff_t
+write_cryptcompress_flow(struct file *file, struct inode *inode,
+                        const char __user *buf, size_t count, loff_t pos,
+                        int *conv_occured)
+{
+       int i;
+       flow_t f;
+       hint_t *hint;
+       int result = 0;
+       size_t to_write = 0;
+       loff_t file_off;
+       reiser4_slide_t win;
+       reiser4_cluster_t clust;
+
+       assert("edward-161", reiser4_schedulable());
+       assert("edward-748", cryptcompress_inode_ok(inode));
+       assert("edward-159", current_blocksize == PAGE_CACHE_SIZE);
+       assert("edward-1274", get_current_context()->grabbed_blocks == 0);
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+
+       result = load_file_hint(file, hint);
+       if (result) {
+               kfree(hint);
+               return result;
+       }
+
+       result =
+           flow_by_inode_cryptcompress(inode, buf, 1 /* user space */ ,
+                                       count, pos, WRITE_OP, &f);
+       if (result)
+               goto out;
+       to_write = f.length;
+
+       /* current write position in file */
+       file_off = pos;
+       reiser4_slide_init(&win);
+       cluster_init_read(&clust, &win);
+       clust.hint = hint;
+
+       result = set_cluster_by_window(inode, &clust, &win, &f, file_off);
+       if (result)
+               goto out;
+
+       if (next_window_stat(&win) == HOLE_WINDOW) {
+               result = write_conversion_hook(file, inode, pos, &clust, NULL);
+               if (result)
+                       goto out;
+               result =
+                   prepare_cluster(inode, file_off, f.length, &clust,
+                                   PCL_APPEND);
+               if (result)
+                       goto out;
+       }
+       do {
+               char *src;
+               unsigned page_off, page_count;
+
+               assert("edward-750", reiser4_schedulable());
+
+               result = write_conversion_hook(file, inode, pos, &clust,
+                                              conv_occured);
+               if (result || *conv_occured)
+                       goto out;
+               result =
+                   prepare_cluster(inode, file_off, f.length, &clust,
+                                   PCL_APPEND);
+               if (result)
+                       goto out;
+
+               assert("edward-751", cryptcompress_inode_ok(inode));
+               assert("edward-204", win.stat == DATA_WINDOW);
+               assert("edward-1288", hint_is_valid(clust.hint));
+               assert("edward-752",
+                      znode_is_write_locked(hint->ext_coord.coord.node));
+
+               put_hint_cluster(&clust, inode, ZNODE_WRITE_LOCK);
+
+               /* set write position in page */
+               page_off = off_to_pgoff(win.off);
+
+               /* copy user's data to cluster pages */
+               for (i = off_to_pg(win.off), src = f.data;
+                    i < count_to_nrpages(win.off + win.count);
+                    i++, src += page_count) {
+                       page_count =
+                           cnt_to_pgcnt(win.off + win.count, i) - page_off;
+
+                       assert("edward-1039",
+                              page_off + page_count <= PAGE_CACHE_SIZE);
+                       assert("edward-287", clust.pages[i] != NULL);
+
+                       lock_page(clust.pages[i]);
+                       result =
+                           __copy_from_user((char *)kmap(clust.pages[i]) +
+                                            page_off, (char __user *)src, page_count);
+                       kunmap(clust.pages[i]);
+                       if (unlikely(result)) {
+                               unlock_page(clust.pages[i]);
+                               result = -EFAULT;
+                               goto err2;
+                       }
+                       SetPageUptodate(clust.pages[i]);
+                       unlock_page(clust.pages[i]);
+                       page_off = 0;
+               }
+               assert("edward-753", cryptcompress_inode_ok(inode));
+
+               set_cluster_pages_dirty(&clust);
+
+               result = try_capture_cluster(&clust, inode);
+               if (result)
+                       goto err2;
+
+               assert("edward-998", f.user == 1);
+
+               move_flow_forward(&f, win.count);
+
+               /* disk cluster may be already clean at this point */
+
+               /* . update cluster
+                  . set hint for new offset
+                  . unlock znode
+                  . update inode
+                  . balance dirty pages
+                */
+               result = balance_dirty_page_cluster(&clust, inode, 0, f.length);
+               if (result)
+                       goto err1;
+               assert("edward-755", hint->lh.owner == NULL);
+               reset_cluster_params(&clust);
+               continue;
+             err2:
+               reiser4_release_cluster_pages_and_jnode(&clust);
+             err1:
+               if (clust.reserved)
+                       free_reserved4cluster(inode,
+                                             &clust,
+                                             estimate_update_cluster(inode));
+               break;
+       } while (f.length);
+      out:
+       done_lh(&hint->lh);
+       if (result == -EEXIST)
+               warning("edward-1407", "write returns EEXIST!\n");
+
+       put_cluster_handle(&clust);
+       save_file_hint(file, hint);
+       kfree(hint);
+       if (buf) {
+               /* if nothing were written - there must be an error */
+               assert("edward-195", ergo((to_write == f.length),
+                                         (result < 0 || *conv_occured)));
+               return (to_write - f.length) ? (to_write - f.length) : result;
+       }
+       return result;
+}
+
+/**
+ * write_cryptcompress - write of struct file_operations
+ * @file: file to write to
+ * @buf: address of user-space buffer
+ * @read_amount: number of bytes to write
+ * @off: position in file to write to
+ *
+ * This is implementation of vfs's write method of struct file_operations for
+ * cryptcompress plugin.
+ */
+ssize_t write_cryptcompress(struct file *file, const char __user *buf,
+                           size_t count, loff_t *off, int *conv)
+{
+       ssize_t result;
+       struct inode *inode;
+       reiser4_context *ctx;
+       loff_t pos = *off;
+       cryptcompress_info_t *info;
+
+       assert("edward-1449", *conv == 0);
+
+       inode = file->f_dentry->d_inode;
+       assert("edward-196", cryptcompress_inode_ok(inode));
+
+       info = cryptcompress_inode_data(inode);
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       mutex_lock(&inode->i_mutex);
+
+       result = generic_write_checks(file, &pos, &count, 0);
+       if (unlikely(result != 0))
+               goto out;
+       if (unlikely(count == 0))
+               goto out;
+       result = remove_suid(file->f_dentry);
+       if (unlikely(result != 0))
+               goto out;
+       /* remove_suid might create a transaction */
+       reiser4_txn_restart(ctx);
+
+       result = write_cryptcompress_flow(file, inode, buf, count, pos, conv);
+
+       if (result < 0)
+               goto out;
+       /* update position in a file */
+       *off = pos + result;
+ out:
+       mutex_unlock(&inode->i_mutex);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+int readpages_cryptcompress(struct file *file, struct address_space *mapping,
+                           struct list_head *pages, unsigned nr_pages)
+{
+       reiser4_context * ctx;
+       int ret;
+
+       ctx = reiser4_init_context(mapping->host->i_sb);
+       if (IS_ERR(ctx)) {
+               ret = PTR_ERR(ctx);
+               goto err;
+       }
+       /* crc files can be built of ctail items only */
+       ret = readpages_ctail(file, mapping, pages);
+       reiser4_exit_context(ctx);
+       if (ret) {
+err:
+               put_pages_list(pages);
+       }
+       return ret;
+}
+
+static reiser4_block_nr cryptcompress_estimate_read(struct inode *inode)
+{
+       /* reserve one block to update stat data item */
+       assert("edward-1193",
+              inode_file_plugin(inode)->estimate.update ==
+              estimate_update_common);
+       return estimate_update_common(inode);
+}
+
+/**
+ * read_cryptcompress - read of struct file_operations
+ * @file: file to read from
+ * @buf: address of user-space buffer
+ * @read_amount: number of bytes to read
+ * @off: position in file to read from
+ *
+ * This is implementation of vfs's read method of struct file_operations for
+ * cryptcompress plugin.
+ */
+ssize_t read_cryptcompress(struct file * file, char __user *buf, size_t size,
+                          loff_t * off)
+{
+       ssize_t result;
+       struct inode *inode;
+       reiser4_context *ctx;
+       cryptcompress_info_t *info;
+       reiser4_block_nr needed;
+
+       inode = file->f_dentry->d_inode;
+       assert("edward-1194", !reiser4_inode_get_flag(inode, REISER4_NO_SD));
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       info = cryptcompress_inode_data(inode);
+       needed = cryptcompress_estimate_read(inode);
+
+       result = reiser4_grab_space(needed, BA_CAN_COMMIT);
+       if (result != 0) {
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       LOCK_CNT_INC(inode_sem_r);
+
+       result = do_sync_read(file, buf, size, off);
+
+       LOCK_CNT_DEC(inode_sem_r);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+
+       return result;
+}
+
+/* If @index > 0, find real disk cluster of the index (@index - 1),
+   If @index == 0 find the real disk cluster of the object of maximal index.
+   Keep incremented index of the result in @found.
+   It succes was returned:
+   (@index == 0 && @found == 0) means that the object doesn't have real disk
+   clusters.
+   (@index != 0 && @found == 0) means that disk cluster of (@index -1) doesn't
+   exist.
+*/
+static int
+find_real_disk_cluster(struct inode *inode, cloff_t * found, cloff_t index)
+{
+       int result;
+       reiser4_key key;
+       loff_t offset;
+       hint_t *hint;
+       lock_handle *lh;
+       lookup_bias bias;
+       coord_t *coord;
+       item_plugin *iplug;
+
+       assert("edward-1131", inode != NULL);
+       assert("edward-95", cryptcompress_inode_ok(inode));
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+       hint_init_zero(hint);
+       lh = &hint->lh;
+
+       bias = (index ? FIND_EXACT : FIND_MAX_NOT_MORE_THAN);
+       offset =
+           (index ? clust_to_off(index, inode) -
+            1 : get_key_offset(reiser4_max_key()));
+
+       key_by_inode_cryptcompress(inode, offset, &key);
+
+       /* find the last item of this object */
+       result =
+           find_cluster_item(hint, &key, ZNODE_READ_LOCK, NULL /* ra_info */,
+                             bias, 0);
+       if (cbk_errored(result)) {
+               done_lh(lh);
+               kfree(hint);
+               return result;
+       }
+       if (result == CBK_COORD_NOTFOUND) {
+               /* no real disk clusters */
+               done_lh(lh);
+               kfree(hint);
+               *found = 0;
+               return 0;
+       }
+       /* disk cluster is found */
+       coord = &hint->ext_coord.coord;
+       coord_clear_iplug(coord);
+       result = zload(coord->node);
+       if (unlikely(result)) {
+               done_lh(lh);
+               kfree(hint);
+               return result;
+       }
+       iplug = item_plugin_by_coord(coord);
+       assert("edward-277", iplug == item_plugin_by_id(CTAIL_ID));
+       assert("edward-1202", ctail_ok(coord));
+
+       item_key_by_coord(coord, &key);
+       *found = off_to_clust(get_key_offset(&key), inode) + 1;
+
+       assert("edward-1132", ergo(index, index == *found));
+
+       zrelse(coord->node);
+       done_lh(lh);
+       kfree(hint);
+       return 0;
+}
+
+static int find_fake_appended(struct inode *inode, cloff_t * index)
+{
+       return find_real_disk_cluster(inode, index,
+                                     0 /* find last real one */ );
+}
+
+/* Set left coord when unit is not found after node_lookup()
+   This takes into account that there can be holes in a sequence
+   of disk clusters */
+
+static void adjust_left_coord(coord_t * left_coord)
+{
+       switch (left_coord->between) {
+       case AFTER_UNIT:
+               left_coord->between = AFTER_ITEM;
+       case AFTER_ITEM:
+       case BEFORE_UNIT:
+               break;
+       default:
+               impossible("edward-1204", "bad left coord to cut");
+       }
+       return;
+}
+
+#define CRC_CUT_TREE_MIN_ITERATIONS 64
+int
+cut_tree_worker_cryptcompress(tap_t * tap, const reiser4_key * from_key,
+                             const reiser4_key * to_key,
+                             reiser4_key * smallest_removed,
+                             struct inode *object, int truncate, int *progress)
+{
+       lock_handle next_node_lock;
+       coord_t left_coord;
+       int result;
+
+       assert("edward-1158", tap->coord->node != NULL);
+       assert("edward-1159", znode_is_write_locked(tap->coord->node));
+       assert("edward-1160", znode_get_level(tap->coord->node) == LEAF_LEVEL);
+
+       *progress = 0;
+       init_lh(&next_node_lock);
+
+       while (1) {
+               znode *node;    /* node from which items are cut */
+               node_plugin *nplug;     /* node plugin for @node */
+
+               node = tap->coord->node;
+
+               /* Move next_node_lock to the next node on the left. */
+               result =
+                   reiser4_get_left_neighbor(&next_node_lock, node,
+                                             ZNODE_WRITE_LOCK,
+                                             GN_CAN_USE_UPPER_LEVELS);
+               if (result != 0 && result != -E_NO_NEIGHBOR)
+                       break;
+               /* FIXME-EDWARD: Check can we delete the node as a whole. */
+               result = reiser4_tap_load(tap);
+               if (result)
+                       return result;
+
+               /* Prepare the second (right) point for cut_node() */
+               if (*progress)
+                       coord_init_last_unit(tap->coord, node);
+
+               else if (item_plugin_by_coord(tap->coord)->b.lookup == NULL)
+                       /* set rightmost unit for the items without lookup method */
+                       tap->coord->unit_pos = coord_last_unit_pos(tap->coord);
+
+               nplug = node->nplug;
+
+               assert("edward-1161", nplug);
+               assert("edward-1162", nplug->lookup);
+
+               /* left_coord is leftmost unit cut from @node */
+               result = nplug->lookup(node, from_key, FIND_EXACT, &left_coord);
+
+               if (IS_CBKERR(result))
+                       break;
+
+               if (result == CBK_COORD_NOTFOUND)
+                       adjust_left_coord(&left_coord);
+
+               /* adjust coordinates so that they are set to existing units */
+               if (coord_set_to_right(&left_coord)
+                   || coord_set_to_left(tap->coord)) {
+                       result = 0;
+                       break;
+               }
+
+               if (coord_compare(&left_coord, tap->coord) ==
+                   COORD_CMP_ON_RIGHT) {
+                       /* keys from @from_key to @to_key are not in the tree */
+                       result = 0;
+                       break;
+               }
+
+               /* cut data from one node */
+               *smallest_removed = *reiser4_min_key();
+               result = kill_node_content(&left_coord,
+                                          tap->coord,
+                                          from_key,
+                                          to_key,
+                                          smallest_removed,
+                                          next_node_lock.node,
+                                          object, truncate);
+#if REISER4_DEBUG
+               /*node_check(node, ~0U); */
+#endif
+               reiser4_tap_relse(tap);
+
+               if (result)
+                       break;
+
+               ++(*progress);
+
+               /* Check whether all items with keys >= from_key were removed
+                * from the tree. */
+               if (keyle(smallest_removed, from_key))
+                       /* result = 0; */
+                       break;
+
+               if (next_node_lock.node == NULL)
+                       break;
+
+               result = reiser4_tap_move(tap, &next_node_lock);
+               done_lh(&next_node_lock);
+               if (result)
+                       break;
+
+               /* Break long cut_tree operation (deletion of a large file) if
+                * atom requires commit. */
+               if (*progress > CRC_CUT_TREE_MIN_ITERATIONS
+                   && current_atom_should_commit()) {
+                       result = -E_REPEAT;
+                       break;
+               }
+       }
+       done_lh(&next_node_lock);
+       return result;
+}
+
+/* Append or expand hole in two steps (exclusive access should be aquired!)
+   1) write zeroes to the current real cluster,
+   2) expand hole via fake clusters (just increase i_size) */
+static int
+cryptcompress_append_hole(struct inode *inode /*contains old i_size */ ,
+                         loff_t new_size)
+{
+       int result = 0;
+       hint_t *hint;
+       lock_handle *lh;
+       loff_t hole_size;
+       int nr_zeroes;
+       reiser4_slide_t win;
+       reiser4_cluster_t clust;
+
+       assert("edward-1133", inode->i_size < new_size);
+       assert("edward-1134", reiser4_schedulable());
+       assert("edward-1135", cryptcompress_inode_ok(inode));
+       assert("edward-1136", current_blocksize == PAGE_CACHE_SIZE);
+       assert("edward-1333", off_to_cloff(inode->i_size, inode) != 0);
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+       hint_init_zero(hint);
+       lh = &hint->lh;
+
+       reiser4_slide_init(&win);
+       cluster_init_read(&clust, &win);
+       clust.hint = hint;
+
+       result = alloc_cluster_pgset(&clust, cluster_nrpages(inode));
+       if (result)
+               goto out;
+       if (off_to_cloff(inode->i_size, inode) == 0)
+               goto fake_append;
+       hole_size = new_size - inode->i_size;
+       nr_zeroes =
+               inode_cluster_size(inode) - off_to_cloff(inode->i_size, inode);
+       if (hole_size < nr_zeroes)
+               nr_zeroes = hole_size;
+       set_window(&clust, &win, inode, inode->i_size,
+                  inode->i_size + nr_zeroes);
+       win.stat = HOLE_WINDOW;
+
+       assert("edward-1137",
+              clust.index == off_to_clust(inode->i_size, inode));
+
+       result = prepare_cluster(inode, 0, 0, &clust, PCL_APPEND);
+
+       assert("edward-1271", !result || result == -ENOSPC);
+       if (result)
+               goto out;
+       assert("edward-1139",
+              clust.dstat == PREP_DISK_CLUSTER ||
+              clust.dstat == UNPR_DISK_CLUSTER);
+
+       assert("edward-1431", hole_size >= nr_zeroes);
+       if (hole_size == nr_zeroes)
+       /* nothing to append anymore */
+               goto out;
+      fake_append:
+       INODE_SET_FIELD(inode, i_size, new_size);
+      out:
+       done_lh(lh);
+       kfree(hint);
+       put_cluster_handle(&clust);
+       return result;
+}
+
+#if REISER4_DEBUG
+static int
+pages_truncate_ok(struct inode *inode, loff_t old_size, pgoff_t start)
+{
+       struct pagevec pvec;
+       int i;
+       int count;
+       int rest;
+
+       rest = count_to_nrpages(old_size) - start;
+
+       pagevec_init(&pvec, 0);
+       count = min_count(pagevec_space(&pvec), rest);
+
+       while (rest) {
+               count = min_count(pagevec_space(&pvec), rest);
+               pvec.nr = find_get_pages(inode->i_mapping, start,
+                                        count, pvec.pages);
+               for (i = 0; i < pagevec_count(&pvec); i++) {
+                       if (PageUptodate(pvec.pages[i])) {
+                               warning("edward-1205",
+                                       "truncated page of index %lu is uptodate",
+                                       pvec.pages[i]->index);
+                               return 0;
+                       }
+               }
+               start += count;
+               rest -= count;
+               pagevec_release(&pvec);
+       }
+       return 1;
+}
+
+static int body_truncate_ok(struct inode *inode, cloff_t aidx)
+{
+       int result;
+       cloff_t raidx;
+
+       result = find_fake_appended(inode, &raidx);
+       return !result && (aidx == raidx);
+}
+#endif
+
+static int
+update_cryptcompress_size(struct inode *inode, reiser4_key * key, int update_sd)
+{
+       return (get_key_offset(key) & ((loff_t) (inode_cluster_size(inode)) - 1)
+               ? 0 : reiser4_update_file_size(inode, key, update_sd));
+}
+
+/* prune cryptcompress file in two steps (exclusive access should be acquired!)
+   1) cut all disk clusters but the last one partially truncated,
+   2) set zeroes and capture last partially truncated page cluster if the last
+      one exists, otherwise truncate via prune fake cluster (just decrease i_size)
+*/
+static int
+prune_cryptcompress(struct inode *inode, loff_t new_size, int update_sd,
+                   cloff_t aidx)
+{
+       int result = 0;
+       unsigned nr_zeroes;
+       loff_t to_prune;
+       loff_t old_size;
+       cloff_t ridx;
+
+       hint_t *hint;
+       lock_handle *lh;
+       reiser4_slide_t win;
+       reiser4_cluster_t clust;
+
+       assert("edward-1140", inode->i_size >= new_size);
+       assert("edward-1141", reiser4_schedulable());
+       assert("edward-1142", cryptcompress_inode_ok(inode));
+       assert("edward-1143", current_blocksize == PAGE_CACHE_SIZE);
+
+       old_size = inode->i_size;
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+       hint_init_zero(hint);
+       lh = &hint->lh;
+
+       reiser4_slide_init(&win);
+       cluster_init_read(&clust, &win);
+       clust.hint = hint;
+
+       /* rightmost completely truncated cluster */
+       ridx = count_to_nrclust(new_size, inode);
+
+       assert("edward-1174", ridx <= aidx);
+       old_size = inode->i_size;
+       if (ridx != aidx) {
+               result = cut_file_items(inode,
+                                       clust_to_off(ridx, inode),
+                                       update_sd,
+                                       clust_to_off(aidx, inode),
+                                       update_cryptcompress_size);
+               if (result)
+                       goto out;
+       }
+       if (!off_to_cloff(new_size, inode)) {
+               /* no partially truncated clusters */
+               assert("edward-1145", inode->i_size == new_size);
+               goto finish;
+       }
+       assert("edward-1146", new_size < inode->i_size);
+
+       to_prune = inode->i_size - new_size;
+
+       /* partial truncate of leftmost cluster,
+          first check if it is fake */
+       result = find_real_disk_cluster(inode, &aidx, ridx);
+       if (result)
+               goto out;
+       if (!aidx)
+               /* yup, this is fake one */
+               goto finish;
+
+       assert("edward-1148", aidx == ridx);
+
+       /* do partial truncate of the leftmost page cluster,
+          then try to capture this one */
+       result = alloc_cluster_pgset(&clust, cluster_nrpages(inode));
+       if (result)
+               goto out;
+       nr_zeroes = (off_to_pgoff(new_size) ?
+                    PAGE_CACHE_SIZE - off_to_pgoff(new_size) : 0);
+       set_window(&clust, &win, inode, new_size, new_size + nr_zeroes);
+       win.stat = HOLE_WINDOW;
+
+       assert("edward-1149", clust.index == ridx - 1);
+
+       result = prepare_cluster(inode, 0, 0, &clust, PCL_TRUNCATE);
+       if (result)
+               goto out;
+       assert("edward-1151",
+              clust.dstat == PREP_DISK_CLUSTER ||
+              clust.dstat == UNPR_DISK_CLUSTER);
+
+       assert("edward-1191", inode->i_size == new_size);
+       assert("edward-1206", body_truncate_ok(inode, ridx));
+      finish:
+       /* drop all the pages that don't have jnodes (i.e. pages
+          which can not be truncated by cut_file_items() because
+          of holes represented by fake disk clusters) including
+          the pages of partially truncated cluster which was
+          released by prepare_cluster() */
+       truncate_inode_pages(inode->i_mapping, new_size);
+       INODE_SET_FIELD(inode, i_size, new_size);
+      out:
+       assert("edward-1334", !result || result == -ENOSPC);
+       assert("edward-1209",
+              pages_truncate_ok(inode, old_size, count_to_nrpages(new_size)));
+       done_lh(lh);
+       kfree(hint);
+       put_cluster_handle(&clust);
+       return result;
+}
+
+/* Prepare cryptcompress file for truncate:
+   prune or append rightmost fake logical clusters (if any)
+*/
+static int
+start_truncate_fake(struct inode *inode, cloff_t aidx, loff_t new_size,
+                   int update_sd)
+{
+       int result = 0;
+       int bytes;
+
+       if (new_size > inode->i_size) {
+               /* append */
+               if (inode->i_size < clust_to_off(aidx, inode))
+                       /* no fake bytes */
+                       return 0;
+               bytes = new_size - inode->i_size;
+               INODE_SET_FIELD(inode, i_size, inode->i_size + bytes);
+       } else {
+               /* prune */
+               if (inode->i_size <= clust_to_off(aidx, inode))
+                       /* no fake bytes */
+                       return 0;
+               bytes =
+                   inode->i_size - max_count(new_size,
+                                             clust_to_off(aidx, inode));
+               if (!bytes)
+                       return 0;
+               INODE_SET_FIELD(inode, i_size, inode->i_size - bytes);
+               /* In the case of fake prune we need to drop page cluster.
+                  There are only 2 cases for partially truncated page:
+                  1. If is is dirty, therefore it is anonymous
+                  (was dirtied via mmap), and will be captured
+                  later via ->capture().
+                  2. If is clean, therefore it is filled by zeroes.
+                  In both cases we don't need to make it dirty and
+                  capture here.
+                */
+               truncate_inode_pages(inode->i_mapping, inode->i_size);
+       }
+       if (update_sd)
+               result = update_sd_cryptcompress(inode);
+       return result;
+}
+
+/* This is called in setattr_cryptcompress when it is used to truncate,
+   and in delete_cryptcompress */
+static int cryptcompress_truncate(struct inode *inode, /* old size */
+                                 loff_t new_size,      /* new size */
+                                 int update_sd)
+{
+       int result;
+       cloff_t aidx;
+
+       result = find_fake_appended(inode, &aidx);
+       if (result)
+               return result;
+       assert("edward-1208",
+              ergo(aidx > 0, inode->i_size > clust_to_off(aidx - 1, inode)));
+
+       result = start_truncate_fake(inode, aidx, new_size, update_sd);
+       if (result)
+               return result;
+       if (inode->i_size == new_size)
+               /* nothing to truncate anymore */
+               return 0;
+       result = (inode->i_size < new_size ?
+                 cryptcompress_append_hole(inode, new_size) :
+                 prune_cryptcompress(inode, new_size, update_sd, aidx));
+       if (!result && update_sd)
+               result = update_sd_cryptcompress(inode);
+       return result;
+}
+
+static void clear_moved_tag_cluster(struct address_space * mapping,
+                                   reiser4_cluster_t * clust)
+{
+       int i;
+       void * ret;
+       read_lock_irq(&mapping->tree_lock);
+       for (i = 0; i < clust->nr_pages; i++) {
+               assert("edward-1438", clust->pages[i] != NULL);
+               ret = radix_tree_tag_clear(&mapping->page_tree,
+                                          clust->pages[i]->index,
+                                          PAGECACHE_TAG_REISER4_MOVED);
+               assert("edward-1439", ret == clust->pages[i]);
+       }
+       read_unlock_irq(&mapping->tree_lock);
+}
+
+/* Capture an anonymous pager cluster. (Page cluser is
+   anonymous if it contains at least one anonymous page */
+static int
+capture_page_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       int result;
+
+       assert("edward-1073", clust != NULL);
+       assert("edward-1074", inode != NULL);
+       assert("edward-1075", clust->dstat == INVAL_DISK_CLUSTER);
+
+       result = prepare_cluster(inode, 0, 0, clust, PCL_APPEND);
+       if (result)
+               return result;
+       set_cluster_pages_dirty(clust);
+       clear_moved_tag_cluster(inode->i_mapping, clust);
+
+       result = try_capture_cluster(clust, inode);
+       put_hint_cluster(clust, inode, ZNODE_WRITE_LOCK);
+       if (unlikely(result)) {
+               /* set cleared tag back, so it will be
+                  possible to capture it again later */
+               read_lock_irq(&inode->i_mapping->tree_lock);
+               radix_tree_tag_set(&inode->i_mapping->page_tree,
+                                  clust_to_pg(clust->index, inode),
+                                  PAGECACHE_TAG_REISER4_MOVED);
+               read_unlock_irq(&inode->i_mapping->tree_lock);
+
+               reiser4_release_cluster_pages_and_jnode(clust);
+       }
+       return result;
+}
+
+#define MAX_CLUSTERS_TO_CAPTURE(inode)    (1024 >> cluster_nrpages_shift(inode))
+
+/* read lock should be acquired */
+static int
+capture_anonymous_clusters(struct address_space *mapping, pgoff_t * index,
+                          int to_capture)
+{
+       int result = 0;
+       int found;
+       struct page *page = NULL;
+       hint_t *hint;
+       lock_handle *lh;
+       reiser4_cluster_t clust;
+
+       assert("edward-1127", mapping != NULL);
+       assert("edward-1128", mapping->host != NULL);
+       assert("edward-1440",  mapping->host->i_mapping == mapping);
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+       hint_init_zero(hint);
+       lh = &hint->lh;
+
+       cluster_init_read(&clust, NULL);
+       clust.hint = hint;
+
+       result = alloc_cluster_pgset(&clust, cluster_nrpages(mapping->host));
+       if (result)
+               goto out;
+
+       while (to_capture > 0) {
+               found =
+                   find_get_pages_tag(mapping, index,
+                                      PAGECACHE_TAG_REISER4_MOVED, 1, &page);
+               if (!found) {
+                       *index = (pgoff_t) - 1;
+                       break;
+               }
+               assert("edward-1109", page != NULL);
+
+               move_cluster_forward(&clust, mapping->host, page->index);
+               result = capture_page_cluster(&clust, mapping->host);
+               page_cache_release(page);
+               if (result)
+                       break;
+               to_capture -= clust.nr_pages;
+       }
+       if (result) {
+               warning("edward-1077",
+                       "Cannot capture anon pages: result=%i (captured=%d)\n",
+                       result,
+                       ((__u32) MAX_CLUSTERS_TO_CAPTURE(mapping->host)) -
+                       to_capture);
+       } else {
+               /* something had to be found */
+               assert("edward-1078",
+                      to_capture <= MAX_CLUSTERS_TO_CAPTURE(mapping->host));
+               if (to_capture <= 0)
+                       /* there may be left more pages */
+                       __mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
+       }
+      out:
+       done_lh(lh);
+       kfree(hint);
+       put_cluster_handle(&clust);
+       return result;
+}
+
+/* Check mapping for existence of not captured dirty pages.
+   This returns !0 if either page tree contains pages tagged
+   PAGECACHE_TAG_REISER4_MOVED */
+static int cryptcompress_inode_has_anon_pages(struct inode *inode)
+{
+       return mapping_tagged(inode->i_mapping, PAGECACHE_TAG_REISER4_MOVED);
+}
+
+/* this is implementation of vfs's writepages method of struct
+   address_space_operations */
+int
+writepages_cryptcompress(struct address_space *mapping,
+                        struct writeback_control *wbc)
+{
+       int result;
+       int to_capture;
+       pgoff_t nrpages;
+       pgoff_t index = 0;
+       cryptcompress_info_t *info;
+       struct inode *inode;
+
+       inode = mapping->host;
+       if (!cryptcompress_inode_has_anon_pages(inode)) {
+               result = 0;
+               goto end;
+       }
+
+       info = cryptcompress_inode_data(inode);
+       nrpages = count_to_nrpages(i_size_read(inode));
+
+       if (wbc->sync_mode != WB_SYNC_ALL)
+               to_capture =
+                   min_count(wbc->nr_to_write, MAX_CLUSTERS_TO_CAPTURE(inode));
+       else
+               to_capture = MAX_CLUSTERS_TO_CAPTURE(inode);
+       do {
+               reiser4_context *ctx;
+
+               ctx = reiser4_init_context(inode->i_sb);
+               if (IS_ERR(ctx)) {
+                       result = PTR_ERR(ctx);
+                       break;
+               }
+               ctx->nobalance = 1;
+
+               assert("edward-1079",
+                      lock_stack_isclean(get_current_lock_stack()));
+
+               LOCK_CNT_INC(inode_sem_r);
+
+               result =
+                   capture_anonymous_clusters(inode->i_mapping, &index,
+                                              to_capture);
+
+               if (result != 0 || wbc->sync_mode != WB_SYNC_ALL) {
+                       reiser4_exit_context(ctx);
+                       break;
+               }
+               result = txnmgr_force_commit_all(inode->i_sb, 0);
+               reiser4_exit_context(ctx);
+       } while (result == 0 && index < nrpages);
+
+      end:
+       if (is_in_reiser4_context()) {
+               if (get_current_context()->nr_captured >= CAPTURE_APAGE_BURST) {
+                       /* there are already pages to flush, flush them out, do
+                          not delay until end of reiser4_sync_inodes */
+                       reiser4_writeout(inode->i_sb, wbc);
+                       get_current_context()->nr_captured = 0;
+               }
+       }
+       return result;
+}
+
+/* plugin->u.file.mmap */
+int mmap_cryptcompress(struct file *file, struct vm_area_struct *vma)
+{
+       int result;
+       struct inode *inode;
+       reiser4_context *ctx;
+
+       inode = file->f_dentry->d_inode;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       /*
+        * generic_file_mmap will do update_atime. Grab space for stat data
+        * update.
+        */
+       result = reiser4_grab_space_force
+               (inode_file_plugin(inode)->estimate.update(inode),
+                BA_CAN_COMMIT);
+       if (result) {
+               reiser4_exit_context(ctx);
+               return result;
+       }
+       result = generic_file_mmap(file, vma);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* plugin->u.file.release */
+/* plugin->u.file.get_block */
+
+/* this is implementation of delete method of file plugin for
+   cryptcompress objects */
+int delete_object_cryptcompress(struct inode *inode)
+{
+       int result;
+
+       assert("edward-429", inode->i_nlink == 0);
+
+       reiser4_txn_restart_current();
+
+       result = cryptcompress_truncate(inode, 0, 0);
+       if (result) {
+               warning("edward-430",
+                       "cannot truncate cryptcompress file  %lli: %i",
+                       (unsigned long long)get_inode_oid(inode),
+                       result);
+       }
+       truncate_inode_pages(inode->i_mapping, 0);
+       /* and remove stat data */
+       return reiser4_delete_object_common(inode);
+}
+
+/* plugin->u.file.setattr method
+   This implements actual truncate (see comments in reiser4/page_cache.c) */
+int setattr_cryptcompress(struct dentry *dentry, struct iattr *attr)
+{
+       int result;
+       struct inode *inode;
+
+       inode = dentry->d_inode;
+       if (attr->ia_valid & ATTR_SIZE) {
+               if (inode->i_size != attr->ia_size) {
+                       reiser4_context *ctx;
+                       loff_t old_size;
+
+                       ctx = reiser4_init_context(dentry->d_inode->i_sb);
+                       if (IS_ERR(ctx))
+                               return PTR_ERR(ctx);
+
+                       inode_check_scale(inode, inode->i_size, attr->ia_size);
+
+                       old_size = inode->i_size;
+
+                       result =
+                           cryptcompress_truncate(inode, attr->ia_size,
+                                                  1 /* update stat data */ );
+                       if (result) {
+                               warning("edward-1192",
+                                       "truncate_cryptcompress failed: oid %lli, "
+                                       "old size %lld, new size %lld, retval %d",
+                                       (unsigned long long)
+                                       get_inode_oid(inode), old_size,
+                                       attr->ia_size, result);
+                       }
+                       context_set_commit_async(ctx);
+                       reiser4_exit_context(ctx);
+               } else
+                       result = 0;
+       } else
+               result = reiser4_setattr_common(dentry, attr);
+       return result;
+}
+
+/* sendfile_cryptcompress - sendfile of struct file_operations */
+ssize_t
+sendfile_cryptcompress(struct file *file, loff_t *ppos, size_t count,
+                      read_actor_t actor, void *target)
+{
+       reiser4_context *ctx;
+       ssize_t result;
+       struct inode *inode;
+       cryptcompress_info_t *info;
+
+       inode = file->f_dentry->d_inode;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       /*
+        * generic_file_sndfile may want to call update_atime. Grab space for
+        * stat data update
+        */
+       result = reiser4_grab_space(estimate_update_common(inode),
+                                   BA_CAN_COMMIT);
+       if (result)
+               goto exit;
+       info = cryptcompress_inode_data(inode);
+
+       result = generic_file_sendfile(file, ppos, count, actor, target);
+ exit:
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/*
+ * release_cryptcompress - release of struct file_operations
+ * @inode: inode of released file
+ * @file: file to release
+ */
+int release_cryptcompress(struct inode *inode, struct file *file)
+{
+       reiser4_context *ctx = reiser4_init_context(inode->i_sb);
+
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       reiser4_free_file_fsdata(file);
+       reiser4_exit_context(ctx);
+       return 0;
+}
+
+#if 0
+int prepare_write_cryptcompress(struct file *file, struct page *page,
+                               unsigned from, unsigned to)
+{
+       return prepare_write_common(file, page, from, to);
+}
+#endif  /*  0  */
+
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 80
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/cryptcompress.h linux-2.6.20/fs/reiser4/plugin/file/cryptcompress.h
--- linux-2.6.20.orig/fs/reiser4/plugin/file/cryptcompress.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/cryptcompress.h 2007-05-06 14:50:43.774999471 +0400
@@ -0,0 +1,554 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* See http://www.namesys.com/cryptcompress_design.html */
+
+#if !defined( __FS_REISER4_CRYPTCOMPRESS_H__ )
+#define __FS_REISER4_CRYPTCOMPRESS_H__
+
+#include "../../page_cache.h"
+#include "../compress/compress.h"
+#include "../crypto/cipher.h"
+
+#include <linux/pagemap.h>
+
+#define MIN_CLUSTER_SHIFT PAGE_CACHE_SHIFT
+#define MAX_CLUSTER_SHIFT 16
+#define MAX_CLUSTER_NRPAGES (1U << MAX_CLUSTER_SHIFT >> PAGE_CACHE_SHIFT)
+#define DC_CHECKSUM_SIZE 4
+
+#define MIN_LATTICE_FACTOR 1
+#define MAX_LATTICE_FACTOR 32
+
+/* this mask contains all non-standard plugins that might
+   be present in reiser4-specific part of inode managed by
+   cryptcompress file plugin */
+#define cryptcompress_mask                             \
+       ((1 << PSET_FILE) |                             \
+        (1 << PSET_CLUSTER) |                          \
+        (1 << PSET_CIPHER) |                           \
+        (1 << PSET_DIGEST) |                           \
+        (1 << PSET_COMPRESSION) |                      \
+        (1 << PSET_COMPRESSION_MODE))
+
+static inline loff_t min_count(loff_t a, loff_t b)
+{
+       return (a < b ? a : b);
+}
+
+static inline loff_t max_count(loff_t a, loff_t b)
+{
+       return (a > b ? a : b);
+}
+
+#if REISER4_DEBUG
+static inline int cluster_shift_ok(int shift)
+{
+       return (shift >= MIN_CLUSTER_SHIFT) && (shift <= MAX_CLUSTER_SHIFT);
+}
+#endif
+
+typedef struct tfm_stream {
+       __u8 *data;
+       size_t size;
+} tfm_stream_t;
+
+typedef enum {
+       INPUT_STREAM,
+       OUTPUT_STREAM,
+       LAST_STREAM
+} tfm_stream_id;
+
+typedef tfm_stream_t *tfm_unit[LAST_STREAM];
+
+static inline __u8 *ts_data(tfm_stream_t * stm)
+{
+       assert("edward-928", stm != NULL);
+       return stm->data;
+}
+
+static inline size_t ts_size(tfm_stream_t * stm)
+{
+       assert("edward-929", stm != NULL);
+       return stm->size;
+}
+
+static inline void set_ts_size(tfm_stream_t * stm, size_t size)
+{
+       assert("edward-930", stm != NULL);
+
+       stm->size = size;
+}
+
+static inline int alloc_ts(tfm_stream_t ** stm)
+{
+       assert("edward-931", stm);
+       assert("edward-932", *stm == NULL);
+
+       *stm = kmalloc(sizeof **stm, reiser4_ctx_gfp_mask_get());
+       if (*stm == NULL)
+               return -ENOMEM;
+       memset(*stm, 0, sizeof **stm);
+       return 0;
+}
+
+static inline void free_ts(tfm_stream_t * stm)
+{
+       assert("edward-933", !ts_data(stm));
+       assert("edward-934", !ts_size(stm));
+
+       kfree(stm);
+}
+
+static inline int alloc_ts_data(tfm_stream_t * stm, size_t size)
+{
+       assert("edward-935", !ts_data(stm));
+       assert("edward-936", !ts_size(stm));
+       assert("edward-937", size != 0);
+
+       stm->data = reiser4_vmalloc(size);
+       if (!stm->data)
+               return -ENOMEM;
+       set_ts_size(stm, size);
+       return 0;
+}
+
+static inline void free_ts_data(tfm_stream_t * stm)
+{
+       assert("edward-938", equi(ts_data(stm), ts_size(stm)));
+
+       if (ts_data(stm))
+               vfree(ts_data(stm));
+       memset(stm, 0, sizeof *stm);
+}
+
+/* Write modes for item conversion in flush convert phase */
+typedef enum {
+       CRC_APPEND_ITEM = 1,
+       CRC_OVERWRITE_ITEM = 2,
+       CRC_CUT_ITEM = 3
+} cryptcompress_write_mode_t;
+
+typedef enum {
+       PCL_UNKNOWN = 0,        /* invalid option */
+       PCL_APPEND = 1,         /* append and/or overwrite */
+       PCL_TRUNCATE = 2        /* truncate */
+} page_cluster_op;
+
+/* Reiser4 file write/read transforms page cluster into disk cluster (and back)
+   using crypto/compression transforms implemented by reiser4 transform plugins.
+   Before each transform we allocate a pair of streams (tfm_unit) and assemble
+   page cluster into the input one. After transform we split output stream into
+   a set of items (disk cluster).
+*/
+typedef struct tfm_cluster {
+       coa_set coa;
+       tfm_unit tun;
+       tfm_action act;
+       int uptodate;
+       int lsize;        /* size of the logical cluster */
+       int len;          /* length of the transform stream */
+} tfm_cluster_t;
+
+static inline coa_t get_coa(tfm_cluster_t * tc, reiser4_compression_id id, tfm_action act)
+{
+       return tc->coa[id][act];
+}
+
+static inline void
+set_coa(tfm_cluster_t * tc, reiser4_compression_id id, tfm_action act, coa_t coa)
+{
+       tc->coa[id][act] = coa;
+}
+
+static inline int
+alloc_coa(tfm_cluster_t * tc, compression_plugin * cplug)
+{
+       coa_t coa;
+
+       coa = cplug->alloc(tc->act);
+       if (IS_ERR(coa))
+               return PTR_ERR(coa);
+       set_coa(tc, cplug->h.id, tc->act, coa);
+       return 0;
+}
+
+static inline int
+grab_coa(tfm_cluster_t * tc, compression_plugin * cplug)
+{
+       return (cplug->alloc && !get_coa(tc, cplug->h.id, tc->act) ?
+               alloc_coa(tc, cplug) : 0);
+}
+
+static inline void free_coa_set(tfm_cluster_t * tc)
+{
+       tfm_action j;
+       reiser4_compression_id i;
+       compression_plugin *cplug;
+
+       assert("edward-810", tc != NULL);
+
+       for (j = 0; j < TFMA_LAST; j++)
+               for (i = 0; i < LAST_COMPRESSION_ID; i++) {
+                       if (!get_coa(tc, i, j))
+                               continue;
+                       cplug = compression_plugin_by_id(i);
+                       assert("edward-812", cplug->free != NULL);
+                       cplug->free(get_coa(tc, i, j), j);
+                       set_coa(tc, i, j, 0);
+               }
+       return;
+}
+
+static inline tfm_stream_t *tfm_stream(tfm_cluster_t * tc, tfm_stream_id id)
+{
+       return tc->tun[id];
+}
+
+static inline void
+set_tfm_stream(tfm_cluster_t * tc, tfm_stream_id id, tfm_stream_t * ts)
+{
+       tc->tun[id] = ts;
+}
+
+static inline __u8 *tfm_stream_data(tfm_cluster_t * tc, tfm_stream_id id)
+{
+       return ts_data(tfm_stream(tc, id));
+}
+
+static inline void
+set_tfm_stream_data(tfm_cluster_t * tc, tfm_stream_id id, __u8 * data)
+{
+       tfm_stream(tc, id)->data = data;
+}
+
+static inline size_t tfm_stream_size(tfm_cluster_t * tc, tfm_stream_id id)
+{
+       return ts_size(tfm_stream(tc, id));
+}
+
+static inline void
+set_tfm_stream_size(tfm_cluster_t * tc, tfm_stream_id id, size_t size)
+{
+       tfm_stream(tc, id)->size = size;
+}
+
+static inline int
+alloc_tfm_stream(tfm_cluster_t * tc, size_t size, tfm_stream_id id)
+{
+       assert("edward-939", tc != NULL);
+       assert("edward-940", !tfm_stream(tc, id));
+
+       tc->tun[id] = kmalloc(sizeof(tfm_stream_t), reiser4_ctx_gfp_mask_get());
+       if (!tc->tun[id])
+               return -ENOMEM;
+       memset(tfm_stream(tc, id), 0, sizeof(tfm_stream_t));
+       return alloc_ts_data(tfm_stream(tc, id), size);
+}
+
+static inline int
+realloc_tfm_stream(tfm_cluster_t * tc, size_t size, tfm_stream_id id)
+{
+       assert("edward-941", tfm_stream_size(tc, id) < size);
+       free_ts_data(tfm_stream(tc, id));
+       return alloc_ts_data(tfm_stream(tc, id), size);
+}
+
+static inline void free_tfm_stream(tfm_cluster_t * tc, tfm_stream_id id)
+{
+       free_ts_data(tfm_stream(tc, id));
+       free_ts(tfm_stream(tc, id));
+       set_tfm_stream(tc, id, 0);
+}
+
+static inline unsigned coa_overrun(compression_plugin * cplug, int ilen)
+{
+       return (cplug->overrun != NULL ? cplug->overrun(ilen) : 0);
+}
+
+static inline void free_tfm_unit(tfm_cluster_t * tc)
+{
+       tfm_stream_id id;
+       for (id = 0; id < LAST_STREAM; id++) {
+               if (!tfm_stream(tc, id))
+                       continue;
+               free_tfm_stream(tc, id);
+       }
+}
+
+static inline void put_tfm_cluster(tfm_cluster_t * tc)
+{
+       assert("edward-942", tc != NULL);
+       free_coa_set(tc);
+       free_tfm_unit(tc);
+}
+
+static inline int tfm_cluster_is_uptodate(tfm_cluster_t * tc)
+{
+       assert("edward-943", tc != NULL);
+       assert("edward-944", tc->uptodate == 0 || tc->uptodate == 1);
+       return (tc->uptodate == 1);
+}
+
+static inline void tfm_cluster_set_uptodate(tfm_cluster_t * tc)
+{
+       assert("edward-945", tc != NULL);
+       assert("edward-946", tc->uptodate == 0 || tc->uptodate == 1);
+       tc->uptodate = 1;
+       return;
+}
+
+static inline void tfm_cluster_clr_uptodate(tfm_cluster_t * tc)
+{
+       assert("edward-947", tc != NULL);
+       assert("edward-948", tc->uptodate == 0 || tc->uptodate == 1);
+       tc->uptodate = 0;
+       return;
+}
+
+static inline int tfm_stream_is_set(tfm_cluster_t * tc, tfm_stream_id id)
+{
+       return (tfm_stream(tc, id) &&
+               tfm_stream_data(tc, id) && tfm_stream_size(tc, id));
+}
+
+static inline int tfm_cluster_is_set(tfm_cluster_t * tc)
+{
+       int i;
+       for (i = 0; i < LAST_STREAM; i++)
+               if (!tfm_stream_is_set(tc, i))
+                       return 0;
+       return 1;
+}
+
+static inline void alternate_streams(tfm_cluster_t * tc)
+{
+       tfm_stream_t *tmp = tfm_stream(tc, INPUT_STREAM);
+
+       set_tfm_stream(tc, INPUT_STREAM, tfm_stream(tc, OUTPUT_STREAM));
+       set_tfm_stream(tc, OUTPUT_STREAM, tmp);
+}
+
+/* a kind of data that we can write to the window */
+typedef enum {
+       DATA_WINDOW,            /* the data we copy form user space */
+       HOLE_WINDOW             /* zeroes if we write hole */
+} window_stat;
+
+/* Sliding window of cluster size which should be set to the approprite position
+   (defined by cluster index) in a file before page cluster modification by
+   file_write. Then we translate file size, offset to write from, number of
+   bytes to write, etc.. to the following configuration needed to estimate
+   number of pages to read before write, etc...
+*/
+typedef struct reiser4_slide {
+       unsigned off;           /* offset we start to write/truncate from */
+       unsigned count;         /* number of bytes (zeroes) to write/truncate */
+       unsigned delta;         /* number of bytes to append to the hole */
+       window_stat stat;       /* a kind of data to write to the window */
+} reiser4_slide_t;
+
+/* The following is a set of possible disk cluster states */
+typedef enum {
+       INVAL_DISK_CLUSTER,     /* unknown state */
+       PREP_DISK_CLUSTER,      /* disk cluster got converted by flush
+                                  at least 1 time */
+       UNPR_DISK_CLUSTER,      /* disk cluster just created and should be
+                                  converted by flush */
+       FAKE_DISK_CLUSTER       /* disk cluster doesn't exist neither in memory
+                                  nor on disk */
+} disk_cluster_stat;
+
+/*
+   While implementing all transforms (from page to disk cluster, and back)
+   reiser4 cluster manager fills the following structure incapsulating pointers
+   to all the clusters for the same index including the sliding window above
+*/
+typedef struct reiser4_cluster {
+       tfm_cluster_t tc;       /* transform cluster */
+       int nr_pages;           /* number of pages */
+       struct page **pages;    /* page cluster */
+       page_cluster_op op;     /* page cluster operation */
+       struct file *file;
+       hint_t *hint;           /* disk cluster item for traversal */
+       disk_cluster_stat dstat;        /* state of the current disk cluster */
+       cloff_t index;          /* offset in the units of cluster size */
+       int index_valid;        /* to validate the index above, if needed */
+       reiser4_slide_t *win;   /* sliding window of cluster size */
+       int reserved;           /* this indicates that space for disk
+                                  cluster modification is reserved */
+#if REISER4_DEBUG
+       reiser4_context *ctx;
+       int reserved_prepped;
+       int reserved_unprepped;
+#endif
+
+} reiser4_cluster_t;
+
+static inline __u8 * tfm_input_data (reiser4_cluster_t * clust)
+{
+       return tfm_stream_data(&clust->tc, INPUT_STREAM);
+}
+
+static inline __u8 * tfm_output_data (reiser4_cluster_t * clust)
+{
+       return tfm_stream_data(&clust->tc, OUTPUT_STREAM);
+}
+
+static inline int reset_cluster_pgset(reiser4_cluster_t * clust, int nrpages)
+{
+       assert("edward-1057", clust->pages != NULL);
+       memset(clust->pages, 0, sizeof(*clust->pages) * nrpages);
+       return 0;
+}
+
+static inline int alloc_cluster_pgset(reiser4_cluster_t * clust, int nrpages)
+{
+       assert("edward-949", clust != NULL);
+       assert("edward-1362", clust->pages == NULL);
+       assert("edward-950", nrpages != 0 && nrpages <= MAX_CLUSTER_NRPAGES);
+
+       clust->pages =
+               kmalloc(sizeof(*clust->pages) * nrpages,
+                       reiser4_ctx_gfp_mask_get());
+       if (!clust->pages)
+               return RETERR(-ENOMEM);
+       reset_cluster_pgset(clust, nrpages);
+       return 0;
+}
+
+static inline void free_cluster_pgset(reiser4_cluster_t * clust)
+{
+       assert("edward-951", clust->pages != NULL);
+       kfree(clust->pages);
+       clust->pages = NULL;
+}
+
+static inline void put_cluster_handle(reiser4_cluster_t * clust)
+{
+       assert("edward-435", clust != NULL);
+
+       put_tfm_cluster(&clust->tc);
+       if (clust->pages)
+               free_cluster_pgset(clust);
+       memset(clust, 0, sizeof *clust);
+}
+
+static inline void inc_keyload_count(crypto_stat_t * data)
+{
+       assert("edward-1410", data != NULL);
+       data->keyload_count++;
+}
+
+static inline void dec_keyload_count(crypto_stat_t * data)
+{
+       assert("edward-1411", data != NULL);
+       assert("edward-1412", data->keyload_count > 0);
+       data->keyload_count--;
+}
+
+/* cryptcompress specific part of reiser4_inode */
+typedef struct cryptcompress_info {
+       crypto_stat_t *crypt;
+       /* the following 2 fields are controlled by compression mode plugin */
+       int compress_toggle; /* current status of compressibility */
+       int lattice_factor;  /* factor of dynamic lattice. FIXME: Have a
+                               compression_toggle to keep the factor */
+#if REISER4_DEBUG
+       int pgcount;              /* number of captured pages */
+#endif
+} cryptcompress_info_t;
+
+static inline void set_compression_toggle (cryptcompress_info_t * info, int val)
+{
+       info->compress_toggle = val;
+}
+
+static inline int get_compression_toggle (cryptcompress_info_t * info)
+{
+       return info->compress_toggle;
+}
+
+static inline int compression_is_on(cryptcompress_info_t * info)
+{
+       return get_compression_toggle(info) == 1;
+}
+
+static inline void turn_on_compression(cryptcompress_info_t * info)
+{
+       set_compression_toggle(info, 1);
+}
+
+static inline void turn_off_compression(cryptcompress_info_t * info)
+{
+       set_compression_toggle(info, 0);
+}
+
+static inline void set_lattice_factor(cryptcompress_info_t * info, int val)
+{
+       info->lattice_factor = val;
+}
+
+static inline int get_lattice_factor(cryptcompress_info_t * info)
+{
+       return info->lattice_factor;
+}
+
+cryptcompress_info_t *cryptcompress_inode_data(const struct inode *);
+int equal_to_rdk(znode *, const reiser4_key *);
+int goto_right_neighbor(coord_t *, lock_handle *);
+int cryptcompress_inode_ok(struct inode *inode);
+int coord_is_unprepped_ctail(const coord_t * coord);
+extern int ctail_read_disk_cluster (reiser4_cluster_t *, struct inode *,
+                                   znode_lock_mode mode);
+extern int do_readpage_ctail(struct inode *, reiser4_cluster_t *,
+                            struct page * page, znode_lock_mode mode);
+extern int ctail_insert_unprepped_cluster(reiser4_cluster_t * clust,
+                                         struct inode * inode);
+extern int readpages_cryptcompress(struct file*, struct address_space*,
+                                  struct list_head*, unsigned);
+int bind_cryptcompress(struct inode *child, struct inode *parent);
+void destroy_inode_cryptcompress(struct inode * inode);
+int grab_cluster_pages(struct inode *inode, reiser4_cluster_t * clust);
+int write_conversion_hook(struct file *file, struct inode * inode, loff_t pos,
+                         reiser4_cluster_t * clust, int * progress);
+crypto_stat_t * inode_crypto_stat (struct inode * inode);
+void inherit_crypto_stat_common(struct inode * parent, struct inode * object,
+                               int (*can_inherit)(struct inode * child,
+                                                  struct inode * parent));
+void reiser4_attach_crypto_stat(struct inode * inode, crypto_stat_t * info);
+void change_crypto_stat(struct inode * inode, crypto_stat_t * new);
+crypto_stat_t * reiser4_alloc_crypto_stat (struct inode * inode);
+
+static inline struct crypto_blkcipher * info_get_cipher(crypto_stat_t * info)
+{
+       return info->cipher;
+}
+
+static inline void info_set_cipher(crypto_stat_t * info,
+                                  struct crypto_blkcipher * tfm)
+{
+       info->cipher = tfm;
+}
+
+static inline struct crypto_hash * info_get_digest(crypto_stat_t * info)
+{
+       return info->digest;
+}
+
+static inline void info_set_digest(crypto_stat_t * info,
+                                  struct crypto_hash * tfm)
+{
+       info->digest = tfm;
+}
+
+#endif                         /* __FS_REISER4_CRYPTCOMPRESS_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/file.c linux-2.6.20/fs/reiser4/plugin/file/file.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/file.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/file.c  2007-05-06 14:50:43.779000721 +0400
@@ -0,0 +1,2821 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/*
+ * this file contains implementations of inode/file/address_space/file plugin
+ * operations specific for "unix file plugin" (plugin id is
+ * UNIX_FILE_PLUGIN_ID). "Unix file" is either built of tail items only
+ * (FORMATTING_ID) or of extent items only (EXTENT_POINTER_ID) or empty (have
+ * no items but stat data)
+ */
+
+#include "../../inode.h"
+#include "../../super.h"
+#include "../../tree_walk.h"
+#include "../../carry.h"
+#include "../../page_cache.h"
+#include "../../ioctl.h"
+#include "../object.h"
+#include "../../safe_link.h"
+
+#include <linux/writeback.h>
+#include <linux/pagevec.h>
+#include <linux/syscalls.h>
+
+
+static int unpack(struct file *file, struct inode *inode, int forever);
+static void drop_access(unix_file_info_t *);
+static int hint_validate(hint_t * hint, const reiser4_key * key, int check_key,
+                        znode_lock_mode lock_mode);
+
+/* Get exclusive access and make sure that file is not partially
+ * converted (It may happen that another process is doing tail
+ * conversion. If so, wait until it completes)
+ */
+static inline void get_exclusive_access_careful(unix_file_info_t * uf_info,
+                                               struct inode *inode)
+{
+        do {
+               get_exclusive_access(uf_info);
+               if (!reiser4_inode_get_flag(inode, REISER4_PART_IN_CONV))
+                       break;
+               drop_exclusive_access(uf_info);
+               schedule();
+       } while (1);
+}
+
+/* get unix file plugin specific portion of inode */
+unix_file_info_t *unix_file_inode_data(const struct inode *inode)
+{
+       return &reiser4_inode_data(inode)->file_plugin_data.unix_file_info;
+}
+
+/**
+ * equal_to_rdk - compare key and znode's right delimiting key
+ * @node: node whose right delimiting key to compare with @key
+ * @key: key to compare with @node's right delimiting key
+ *
+ * Returns true if @key is equal to right delimiting key of @node.
+ */
+int equal_to_rdk(znode *node, const reiser4_key *key)
+{
+       int result;
+
+       read_lock_dk(znode_get_tree(node));
+       result = keyeq(key, znode_get_rd_key(node));
+       read_unlock_dk(znode_get_tree(node));
+       return result;
+}
+
+#if REISER4_DEBUG
+
+/**
+ * equal_to_ldk - compare key and znode's left delimiting key
+ * @node: node whose left delimiting key to compare with @key
+ * @key: key to compare with @node's left delimiting key
+ *
+ * Returns true if @key is equal to left delimiting key of @node.
+ */
+int equal_to_ldk(znode *node, const reiser4_key *key)
+{
+       int result;
+
+       read_lock_dk(znode_get_tree(node));
+       result = keyeq(key, znode_get_ld_key(node));
+       read_unlock_dk(znode_get_tree(node));
+       return result;
+}
+
+/**
+ * check_coord - check whether coord corresponds to key
+ * @coord: coord to check
+ * @key: key @coord has to correspond to
+ *
+ * Returns true if @coord is set as if it was set as result of lookup with @key
+ * in coord->node.
+ */
+static int check_coord(const coord_t *coord, const reiser4_key *key)
+{
+       coord_t twin;
+
+       node_plugin_by_node(coord->node)->lookup(coord->node, key,
+                                                FIND_MAX_NOT_MORE_THAN, &twin);
+       return coords_equal(coord, &twin);
+}
+
+#endif /* REISER4_DEBUG */
+
+/**
+ * init_uf_coord - initialize extended coord
+ * @uf_coord:
+ * @lh:
+ *
+ *
+ */
+void init_uf_coord(uf_coord_t *uf_coord, lock_handle *lh)
+{
+       coord_init_zero(&uf_coord->coord);
+       coord_clear_iplug(&uf_coord->coord);
+       uf_coord->lh = lh;
+       init_lh(lh);
+       memset(&uf_coord->extension, 0, sizeof(uf_coord->extension));
+       uf_coord->valid = 0;
+}
+
+static void validate_extended_coord(uf_coord_t *uf_coord, loff_t offset)
+{
+       assert("vs-1333", uf_coord->valid == 0);
+
+       if (coord_is_between_items(&uf_coord->coord))
+               return;
+
+       assert("vs-1348",
+              item_plugin_by_coord(&uf_coord->coord)->s.file.
+              init_coord_extension);
+
+       item_body_by_coord(&uf_coord->coord);
+       item_plugin_by_coord(&uf_coord->coord)->s.file.
+           init_coord_extension(uf_coord, offset);
+}
+
+/**
+ * goto_right_neighbor - lock right neighbor, drop current node lock
+ * @coord:
+ * @lh:
+ *
+ * Obtain lock on right neighbor and drop lock on current node.
+ */
+int goto_right_neighbor(coord_t *coord, lock_handle *lh)
+{
+       int result;
+       lock_handle lh_right;
+
+       assert("vs-1100", znode_is_locked(coord->node));
+
+       init_lh(&lh_right);
+       result = reiser4_get_right_neighbor(&lh_right, coord->node,
+                                           znode_is_wlocked(coord->node) ?
+                                           ZNODE_WRITE_LOCK : ZNODE_READ_LOCK,
+                                           GN_CAN_USE_UPPER_LEVELS);
+       if (result) {
+               done_lh(&lh_right);
+               return result;
+       }
+
+       /*
+        * we hold two longterm locks on neighboring nodes. Unlock left of
+        * them
+        */
+       done_lh(lh);
+
+       coord_init_first_unit_nocheck(coord, lh_right.node);
+       move_lh(lh, &lh_right);
+
+       return 0;
+
+}
+
+/**
+ * set_file_state
+ * @uf_info:
+ * @cbk_result:
+ * @level:
+ *
+ * This is to be used by find_file_item and in find_file_state to
+ * determine real state of file
+ */
+static void set_file_state(unix_file_info_t *uf_info, int cbk_result,
+                          tree_level level)
+{
+       if (cbk_errored(cbk_result))
+               /* error happened in find_file_item */
+               return;
+
+       assert("vs-1164", level == LEAF_LEVEL || level == TWIG_LEVEL);
+
+       if (uf_info->container == UF_CONTAINER_UNKNOWN) {
+               /*
+                * container is unknown, therefore conversion can not be in
+                * progress
+                */
+               assert("",
+                      !reiser4_inode_get_flag(unix_file_info_to_inode(uf_info),
+                                              REISER4_PART_IN_CONV));
+               if (cbk_result == CBK_COORD_NOTFOUND)
+                       uf_info->container = UF_CONTAINER_EMPTY;
+               else if (level == LEAF_LEVEL)
+                       uf_info->container = UF_CONTAINER_TAILS;
+               else
+                       uf_info->container = UF_CONTAINER_EXTENTS;
+       } else {
+               /*
+                * file state is known, check whether it is set correctly if
+                * file is not being tail converted
+                */
+               if (!reiser4_inode_get_flag(unix_file_info_to_inode(uf_info),
+                                           REISER4_PART_IN_CONV)) {
+                       assert("vs-1162",
+                              ergo(level == LEAF_LEVEL &&
+                                   cbk_result == CBK_COORD_FOUND,
+                                   uf_info->container == UF_CONTAINER_TAILS));
+                       assert("vs-1165",
+                              ergo(level == TWIG_LEVEL &&
+                                   cbk_result == CBK_COORD_FOUND,
+                                   uf_info->container == UF_CONTAINER_EXTENTS));
+               }
+       }
+}
+
+int find_file_item_nohint(coord_t *coord, lock_handle *lh,
+                         const reiser4_key *key, znode_lock_mode lock_mode,
+                         struct inode *inode)
+{
+       return reiser4_object_lookup(inode, key, coord, lh, lock_mode,
+                                    FIND_MAX_NOT_MORE_THAN,
+                                    TWIG_LEVEL, LEAF_LEVEL,
+                                    (lock_mode == ZNODE_READ_LOCK) ? CBK_UNIQUE :
+                                    (CBK_UNIQUE | CBK_FOR_INSERT),
+                                    NULL /* ra_info */ );
+}
+
+/**
+ * find_file_item - look for file item in the tree
+ * @hint: provides coordinate, lock handle, seal
+ * @key: key for search
+ * @mode: mode of lock to put on returned node
+ * @ra_info:
+ * @inode:
+ *
+ * This finds position in the tree corresponding to @key. It first tries to use
+ * @hint's seal if it is set.
+ */
+int find_file_item(hint_t *hint, const reiser4_key *key,
+                  znode_lock_mode lock_mode,
+                  struct inode *inode)
+{
+       int result;
+       coord_t *coord;
+       lock_handle *lh;
+
+       assert("nikita-3030", reiser4_schedulable());
+       assert("vs-1707", hint != NULL);
+       assert("vs-47", inode != NULL);
+
+       coord = &hint->ext_coord.coord;
+       lh = hint->ext_coord.lh;
+       init_lh(lh);
+
+       result = hint_validate(hint, key, 1 /* check key */, lock_mode);
+       if (!result) {
+               if (coord->between == AFTER_UNIT &&
+                   equal_to_rdk(coord->node, key)) {
+                       result = goto_right_neighbor(coord, lh);
+                       if (result == -E_NO_NEIGHBOR)
+                               return RETERR(-EIO);
+                       if (result)
+                               return result;
+                       assert("vs-1152", equal_to_ldk(coord->node, key));
+                       /*
+                        * we moved to different node. Invalidate coord
+                        * extension, zload is necessary to init it again
+                        */
+                       hint->ext_coord.valid = 0;
+               }
+
+               set_file_state(unix_file_inode_data(inode), CBK_COORD_FOUND,
+                              znode_get_level(coord->node));
+
+               return CBK_COORD_FOUND;
+       }
+
+       coord_init_zero(coord);
+       result = find_file_item_nohint(coord, lh, key, lock_mode, inode);
+       set_file_state(unix_file_inode_data(inode), result,
+                      znode_get_level(coord->node));
+
+       /* FIXME: we might already have coord extension initialized */
+       hint->ext_coord.valid = 0;
+       return result;
+}
+
+/* plugin->u.file.write_flowom = NULL
+   plugin->u.file.read_flow = NULL */
+
+void hint_init_zero(hint_t * hint)
+{
+       memset(hint, 0, sizeof(*hint));
+       init_lh(&hint->lh);
+       hint->ext_coord.lh = &hint->lh;
+}
+
+static int find_file_state(struct inode *inode, unix_file_info_t *uf_info)
+{
+       int result;
+       reiser4_key key;
+       coord_t coord;
+       lock_handle lh;
+
+       assert("vs-1628", ea_obtained(uf_info));
+
+       if (uf_info->container == UF_CONTAINER_UNKNOWN) {
+               key_by_inode_and_offset_common(inode, 0, &key);
+               init_lh(&lh);
+               result = find_file_item_nohint(&coord, &lh, &key,
+                                              ZNODE_READ_LOCK, inode);
+               set_file_state(uf_info, result, znode_get_level(coord.node));
+               done_lh(&lh);
+               if (!cbk_errored(result))
+                       result = 0;
+       } else
+               result = 0;
+       assert("vs-1074",
+              ergo(result == 0, uf_info->container != UF_CONTAINER_UNKNOWN));
+       reiser4_txn_restart_current();
+       return result;
+}
+
+/* estimate and reserve space needed to truncate page which gets partially truncated: one block for page itself, stat
+   data update (estimate_one_insert_into_item) and one item insertion (estimate_one_insert_into_item) which may happen
+   if page corresponds to hole extent and unallocated one will have to be created */
+static int reserve_partial_page(reiser4_tree * tree)
+{
+       grab_space_enable();
+       return reiser4_grab_reserved(reiser4_get_current_sb(),
+                                    1 +
+                                    2 * estimate_one_insert_into_item(tree),
+                                    BA_CAN_COMMIT);
+}
+
+/* estimate and reserve space needed to cut one item and update one stat data */
+static int reserve_cut_iteration(reiser4_tree * tree)
+{
+       __u64 estimate = estimate_one_item_removal(tree)
+           + estimate_one_insert_into_item(tree);
+
+       assert("nikita-3172", lock_stack_isclean(get_current_lock_stack()));
+
+       grab_space_enable();
+       /* We need to double our estimate now that we can delete more than one
+          node. */
+       return reiser4_grab_reserved(reiser4_get_current_sb(), estimate * 2,
+                                    BA_CAN_COMMIT);
+}
+
+int reiser4_update_file_size(struct inode *inode, reiser4_key * key,
+                            int update_sd)
+{
+       int result = 0;
+
+       INODE_SET_FIELD(inode, i_size, get_key_offset(key));
+       if (update_sd) {
+               inode->i_ctime = inode->i_mtime = CURRENT_TIME;
+               result = reiser4_update_sd(inode);
+       }
+       return result;
+}
+
+/* cut file items one by one starting from the last one until new file size (inode->i_size) is reached. Reserve space
+   and update file stat data on every single cut from the tree */
+int
+cut_file_items(struct inode *inode, loff_t new_size, int update_sd,
+              loff_t cur_size, int (*update_actor) (struct inode *,
+                                                    reiser4_key *, int))
+{
+       reiser4_key from_key, to_key;
+       reiser4_key smallest_removed;
+       file_plugin *fplug = inode_file_plugin(inode);
+       int result;
+       int progress = 0;
+
+       assert("vs-1248",
+              fplug == file_plugin_by_id(UNIX_FILE_PLUGIN_ID) ||
+              fplug == file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID));
+
+       fplug->key_by_inode(inode, new_size, &from_key);
+       to_key = from_key;
+       set_key_offset(&to_key, cur_size - 1 /*get_key_offset(reiser4_max_key()) */ );
+       /* this loop normally runs just once */
+       while (1) {
+               result = reserve_cut_iteration(reiser4_tree_by_inode(inode));
+               if (result)
+                       break;
+
+               result = reiser4_cut_tree_object(current_tree, &from_key, &to_key,
+                                                &smallest_removed, inode, 1,
+                                                &progress);
+               if (result == -E_REPEAT) {
+                       /* -E_REPEAT is a signal to interrupt a long file truncation process */
+                       if (progress) {
+                               result =
+                                   update_actor(inode, &smallest_removed,
+                                                update_sd);
+                               if (result)
+                                       break;
+                       }
+
+                       /* the below does up(sbinfo->delete_mutex). Do not get folled */
+                       reiser4_release_reserved(inode->i_sb);
+
+                       /* reiser4_cut_tree_object() was interrupted probably because
+                        * current atom requires commit, we have to release
+                        * transaction handle to allow atom commit. */
+                       reiser4_txn_restart_current();
+                       continue;
+               }
+               if (result
+                   && !(result == CBK_COORD_NOTFOUND && new_size == 0
+                        && inode->i_size == 0))
+                       break;
+
+               set_key_offset(&smallest_removed, new_size);
+               /* Final sd update after the file gets its correct size */
+               result = update_actor(inode, &smallest_removed, update_sd);
+               break;
+       }
+
+       /* the below does up(sbinfo->delete_mutex). Do not get folled */
+       reiser4_release_reserved(inode->i_sb);
+
+       return result;
+}
+
+int find_or_create_extent(struct page *page);
+
+/* part of truncate_file_body: it is called when truncate is used to make file
+   shorter */
+static int shorten_file(struct inode *inode, loff_t new_size)
+{
+       int result;
+       struct page *page;
+       int padd_from;
+       unsigned long index;
+       char *kaddr;
+       unix_file_info_t *uf_info;
+
+       /*
+        * all items of ordinary reiser4 file are grouped together. That is why
+        * we can use reiser4_cut_tree. Plan B files (for instance) can not be
+        * truncated that simply
+        */
+       result = cut_file_items(inode, new_size, 1 /*update_sd */ ,
+                               get_key_offset(reiser4_max_key()),
+                               reiser4_update_file_size);
+       if (result)
+               return result;
+
+       uf_info = unix_file_inode_data(inode);
+       assert("vs-1105", new_size == inode->i_size);
+       if (new_size == 0) {
+               uf_info->container = UF_CONTAINER_EMPTY;
+               return 0;
+       }
+
+       result = find_file_state(inode, uf_info);
+       if (result)
+               return result;
+       if (uf_info->container == UF_CONTAINER_TAILS)
+               /*
+                * No need to worry about zeroing last page after new file
+                * end
+                */
+               return 0;
+
+       padd_from = inode->i_size & (PAGE_CACHE_SIZE - 1);
+       if (!padd_from)
+               /* file is truncated to page boundary */
+               return 0;
+
+       result = reserve_partial_page(reiser4_tree_by_inode(inode));
+       if (result) {
+               reiser4_release_reserved(inode->i_sb);
+               return result;
+       }
+
+       /* last page is partially truncated - zero its content */
+       index = (inode->i_size >> PAGE_CACHE_SHIFT);
+       page = read_mapping_page(inode->i_mapping, index, NULL);
+       if (IS_ERR(page)) {
+               /*
+                * the below does up(sbinfo->delete_mutex). Do not get
+                * confused
+                */
+               reiser4_release_reserved(inode->i_sb);
+               if (likely(PTR_ERR(page) == -EINVAL)) {
+                       /* looks like file is built of tail items */
+                       return 0;
+               }
+               return PTR_ERR(page);
+       }
+       wait_on_page_locked(page);
+       if (!PageUptodate(page)) {
+               page_cache_release(page);
+               /*
+                * the below does up(sbinfo->delete_mutex). Do not get
+                * confused
+                */
+               reiser4_release_reserved(inode->i_sb);
+               return RETERR(-EIO);
+       }
+
+       /*
+        * if page correspons to hole extent unit - unallocated one will be
+        * created here. This is not necessary
+        */
+       result = find_or_create_extent(page);
+
+       /*
+        * FIXME: cut_file_items has already updated inode. Probably it would
+        * be better to update it here when file is really truncated
+        */
+       if (result) {
+               page_cache_release(page);
+               /*
+                * the below does up(sbinfo->delete_mutex). Do not get
+                * confused
+                */
+               reiser4_release_reserved(inode->i_sb);
+               return result;
+       }
+
+       lock_page(page);
+       assert("vs-1066", PageLocked(page));
+       kaddr = kmap_atomic(page, KM_USER0);
+       memset(kaddr + padd_from, 0, PAGE_CACHE_SIZE - padd_from);
+       flush_dcache_page(page);
+       kunmap_atomic(kaddr, KM_USER0);
+       unlock_page(page);
+       page_cache_release(page);
+       /* the below does up(sbinfo->delete_mutex). Do not get confused */
+       reiser4_release_reserved(inode->i_sb);
+       return 0;
+}
+
+/**
+ * should_have_notail
+ * @uf_info:
+ * @new_size:
+ *
+ * Calls formatting plugin to see whether file of size @new_size has to be
+ * stored in unformatted nodes or in tail items. 0 is returned for later case.
+ */
+static int should_have_notail(const unix_file_info_t *uf_info, loff_t new_size)
+{
+       if (!uf_info->tplug)
+               return 1;
+       return !uf_info->tplug->have_tail(unix_file_info_to_inode(uf_info),
+                                         new_size);
+
+}
+
+/**
+ * truncate_file_body - change length of file
+ * @inode: inode of file
+ * @new_size: new file length
+ *
+ * Adjusts items file @inode is built of to match @new_size. It may either cut
+ * items or add them to represent a hole at the end of file. The caller has to
+ * obtain exclusive access to the file.
+ */
+static int truncate_file_body(struct inode *inode, loff_t new_size)
+{
+       int result;
+
+       if (inode->i_size < new_size) {
+               /* expanding truncate */
+               struct dentry dentry;
+               struct file file;
+               unix_file_info_t *uf_info;
+
+               dentry.d_inode = inode;
+               file.f_dentry = &dentry;
+               file.private_data = NULL;
+               file.f_pos = new_size;
+               file.private_data = NULL;
+               uf_info = unix_file_inode_data(inode);
+               result = find_file_state(inode, uf_info);
+               if (result)
+                       return result;
+
+               if (should_have_notail(uf_info, new_size)) {
+                       /*
+                        * file of size @new_size has to be built of
+                        * extents. If it is built of tails - convert to
+                        * extents
+                        */
+                       if (uf_info->container ==  UF_CONTAINER_TAILS) {
+                               /*
+                                * if file is being convered by another process
+                                * - wait until it completes
+                                */
+                               while (1) {
+                                       if (reiser4_inode_get_flag(inode,
+                                                                  REISER4_PART_IN_CONV)) {
+                                               drop_exclusive_access(uf_info);
+                                               schedule();
+                                               get_exclusive_access(uf_info);
+                                               continue;
+                                       }
+                                       break;
+                               }
+
+                               if (uf_info->container ==  UF_CONTAINER_TAILS) {
+                                       result = tail2extent(uf_info);
+                                       if (result)
+                                               return result;
+                               }
+                       }
+                       result = reiser4_write_extent(&file, NULL, 0,
+                                                     &new_size);
+                       if (result)
+                               return result;
+                       uf_info->container = UF_CONTAINER_EXTENTS;
+               } else {
+                       if (uf_info->container ==  UF_CONTAINER_EXTENTS) {
+                               result = reiser4_write_extent(&file, NULL, 0,
+                                                             &new_size);
+                               if (result)
+                                       return result;
+                       } else {
+                               result = reiser4_write_tail(&file, NULL, 0,
+                                                           &new_size);
+                               if (result)
+                                       return result;
+                               uf_info->container = UF_CONTAINER_TAILS;
+                       }
+               }
+               BUG_ON(result > 0);
+               INODE_SET_FIELD(inode, i_size, new_size);
+               file_update_time(&file);
+               result = reiser4_update_sd(inode);
+               BUG_ON(result != 0);
+               reiser4_free_file_fsdata(&file);
+       } else
+               result = shorten_file(inode, new_size);
+       return result;
+}
+
+/* plugin->u.write_sd_by_inode = write_sd_by_inode_common */
+
+/**
+ * load_file_hint - copy hint from struct file to local variable
+ * @file: file to get hint from
+ * @hint: structure to fill
+ *
+ * Reiser4 specific portion of struct file may contain information (hint)
+ * stored on exiting from previous read or write. That information includes
+ * seal of znode and coord within that znode where previous read or write
+ * stopped. This function copies that information to @hint if it was stored or
+ * initializes @hint by 0s otherwise.
+ */
+int load_file_hint(struct file *file, hint_t *hint)
+{
+       reiser4_file_fsdata *fsdata;
+
+       if (file) {
+               fsdata = reiser4_get_file_fsdata(file);
+               if (IS_ERR(fsdata))
+                       return PTR_ERR(fsdata);
+
+               spin_lock_inode(file->f_dentry->d_inode);
+               if (reiser4_seal_is_set(&fsdata->reg.hint.seal)) {
+                       *hint = fsdata->reg.hint;
+                       init_lh(&hint->lh);
+                       hint->ext_coord.lh = &hint->lh;
+                       spin_unlock_inode(file->f_dentry->d_inode);
+                       /*
+                        * force re-validation of the coord on the first
+                        * iteration of the read/write loop.
+                        */
+                       hint->ext_coord.valid = 0;
+                       assert("nikita-19892", coords_equal(&hint->seal.coord1,
+                                                           &hint->ext_coord.
+                                                           coord));
+                       return 0;
+               }
+               memset(&fsdata->reg.hint, 0, sizeof(hint_t));
+               spin_unlock_inode(file->f_dentry->d_inode);
+       }
+       hint_init_zero(hint);
+       return 0;
+}
+
+/**
+ * save_file_hint - copy hint to reiser4 private struct file's part
+ * @file: file to save hint in
+ * @hint: hint to save
+ *
+ * This copies @hint to reiser4 private part of struct file. It can help
+ * speedup future accesses to the file.
+ */
+void save_file_hint(struct file *file, const hint_t *hint)
+{
+       reiser4_file_fsdata *fsdata;
+
+       assert("edward-1337", hint != NULL);
+
+       if (!file || !reiser4_seal_is_set(&hint->seal))
+               return;
+       fsdata = reiser4_get_file_fsdata(file);
+       assert("vs-965", !IS_ERR(fsdata));
+       assert("nikita-19891",
+              coords_equal(&hint->seal.coord1, &hint->ext_coord.coord));
+       assert("vs-30", hint->lh.owner == NULL);
+       spin_lock_inode(file->f_dentry->d_inode);
+       fsdata->reg.hint = *hint;
+       spin_unlock_inode(file->f_dentry->d_inode);
+       return;
+}
+
+void reiser4_unset_hint(hint_t * hint)
+{
+       assert("vs-1315", hint);
+       hint->ext_coord.valid = 0;
+       reiser4_seal_done(&hint->seal);
+       done_lh(&hint->lh);
+}
+
+/* coord must be set properly. So, that reiser4_set_hint
+   has nothing to do */
+void reiser4_set_hint(hint_t * hint, const reiser4_key * key,
+                     znode_lock_mode mode)
+{
+       ON_DEBUG(coord_t * coord = &hint->ext_coord.coord);
+       assert("vs-1207", WITH_DATA(coord->node, check_coord(coord, key)));
+
+       reiser4_seal_init(&hint->seal, &hint->ext_coord.coord, key);
+       hint->offset = get_key_offset(key);
+       hint->mode = mode;
+       done_lh(&hint->lh);
+}
+
+int hint_is_set(const hint_t * hint)
+{
+       return reiser4_seal_is_set(&hint->seal);
+}
+
+#if REISER4_DEBUG
+static int all_but_offset_key_eq(const reiser4_key * k1, const reiser4_key * k2)
+{
+       return (get_key_locality(k1) == get_key_locality(k2) &&
+               get_key_type(k1) == get_key_type(k2) &&
+               get_key_band(k1) == get_key_band(k2) &&
+               get_key_ordering(k1) == get_key_ordering(k2) &&
+               get_key_objectid(k1) == get_key_objectid(k2));
+}
+#endif
+
+static int
+hint_validate(hint_t * hint, const reiser4_key * key, int check_key,
+             znode_lock_mode lock_mode)
+{
+       if (!hint || !hint_is_set(hint) || hint->mode != lock_mode)
+               /* hint either not set or set by different operation */
+               return RETERR(-E_REPEAT);
+
+       assert("vs-1277", all_but_offset_key_eq(key, &hint->seal.key));
+
+       if (check_key && get_key_offset(key) != hint->offset)
+               /* hint is set for different key */
+               return RETERR(-E_REPEAT);
+
+       assert("vs-31", hint->ext_coord.lh == &hint->lh);
+       return reiser4_seal_validate(&hint->seal, &hint->ext_coord.coord, key,
+                                    hint->ext_coord.lh, lock_mode,
+                                    ZNODE_LOCK_LOPRI);
+}
+
+/**
+ * find_or_create_extent -
+ * @page:
+ *
+ *
+ */
+/* look for place at twig level for extent corresponding to page, call extent's writepage method to create
+   unallocated extent if it does not exist yet, initialize jnode, capture page */
+int find_or_create_extent(struct page *page)
+{
+       int result;
+       struct inode *inode;
+       int plugged_hole;
+
+       jnode *node;
+
+       assert("vs-1065", page->mapping && page->mapping->host);
+       inode = page->mapping->host;
+
+       lock_page(page);
+       node = jnode_of_page(page);
+       if (IS_ERR(node)) {
+               unlock_page(page);
+               return PTR_ERR(node);
+       }
+       JF_SET(node, JNODE_WRITE_PREPARED);
+       unlock_page(page);
+
+       if (node->blocknr == 0) {
+               plugged_hole = 0;
+               result = reiser4_update_extent(inode, node, page_offset(page),
+                                              &plugged_hole);
+               if (result) {
+                       JF_CLR(node, JNODE_WRITE_PREPARED);
+                       jput(node);
+                       warning("", "reiser4_update_extent failed: %d", result);
+                       return result;
+               }
+               if (plugged_hole)
+                       reiser4_update_sd(inode);
+       } else {
+               spin_lock_jnode(node);
+               result = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+               BUG_ON(result != 0);
+               jnode_make_dirty_locked(node);
+               spin_unlock_jnode(node);
+       }
+
+       BUG_ON(node->atom == NULL);
+       JF_CLR(node, JNODE_WRITE_PREPARED);
+       jput(node);
+
+       if (get_current_context()->entd) {
+               entd_context *ent = get_entd_context(node->tree->super);
+
+               if (ent->cur_request->page == page)
+                       ent->cur_request->node = node;
+       }
+       return 0;
+}
+
+/**
+ * has_anonymous_pages - check whether inode has pages dirtied via mmap
+ * @inode: inode to check
+ *
+ * Returns true if inode's mapping has dirty pages which do not belong to any
+ * atom. Those are either tagged PAGECACHE_TAG_REISER4_MOVED in mapping's page
+ * tree or were eflushed and can be found via jnodes tagged
+ * EFLUSH_TAG_ANONYMOUS in radix tree of jnodes.
+ */
+static int has_anonymous_pages(struct inode *inode)
+{
+       int result;
+
+       read_lock_irq(&inode->i_mapping->tree_lock);
+       result = radix_tree_tagged(&inode->i_mapping->page_tree, PAGECACHE_TAG_REISER4_MOVED);
+       read_unlock_irq(&inode->i_mapping->tree_lock);
+       return result;
+}
+
+/**
+ * capture_page_and_create_extent -
+ * @page: page to be captured
+ *
+ * Grabs space for extent creation and stat data update and calls function to
+ * do actual work.
+ */
+static int capture_page_and_create_extent(struct page *page)
+{
+       int result;
+       struct inode *inode;
+
+       assert("vs-1084", page->mapping && page->mapping->host);
+       inode = page->mapping->host;
+       assert("vs-1139",
+              unix_file_inode_data(inode)->container == UF_CONTAINER_EXTENTS);
+       /* page belongs to file */
+       assert("vs-1393",
+              inode->i_size > page_offset(page));
+
+       /* page capture may require extent creation (if it does not exist yet)
+          and stat data's update (number of blocks changes on extent
+          creation) */
+       grab_space_enable();
+       result = reiser4_grab_space(2 * estimate_one_insert_into_item
+                                   (reiser4_tree_by_inode(inode)),
+                                   BA_CAN_COMMIT);
+       if (likely(!result))
+               result = find_or_create_extent(page);
+
+       if (result != 0)
+               SetPageError(page);
+       return result;
+}
+
+/* this is implementation of method commit_write of struct
+   address_space_operations for unix file plugin */
+int
+commit_write_unix_file(struct file *file, struct page *page,
+                      unsigned from, unsigned to)
+{
+       reiser4_context *ctx;
+       struct inode *inode;
+       int result;
+
+       assert("umka-3101", file != NULL);
+       assert("umka-3102", page != NULL);
+       assert("umka-3093", PageLocked(page));
+
+       SetPageUptodate(page);
+
+       inode = page->mapping->host;
+       ctx = reiser4_init_context(page->mapping->host->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       page_cache_get(page);
+       unlock_page(page);
+       result = capture_page_and_create_extent(page);
+       lock_page(page);
+       page_cache_release(page);
+
+       /* don't commit transaction under inode semaphore */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/*
+ * Support for "anonymous" pages and jnodes.
+ *
+ * When file is write-accessed through mmap pages can be dirtied from the user
+ * level. In this case kernel is not notified until one of following happens:
+ *
+ *     (1) msync()
+ *
+ *     (2) truncate() (either explicit or through unlink)
+ *
+ *     (3) VM scanner starts reclaiming mapped pages, dirtying them before
+ *     starting write-back.
+ *
+ * As a result of (3) ->writepage may be called on a dirty page without
+ * jnode. Such page is called "anonymous" in reiser4. Certain work-loads
+ * (iozone) generate huge number of anonymous pages. Emergency flush handles
+ * this situation by creating jnode for anonymous page, starting IO on the
+ * page, and marking jnode with JNODE_KEEPME bit so that it's not thrown out of
+ * memory. Such jnode is also called anonymous.
+ *
+ * reiser4_sync_sb() method tries to insert anonymous pages and jnodes into
+ * tree. This is done by capture_anonymous_*() functions below.
+ */
+
+/**
+ * capture_anonymous_page - involve page into transaction
+ * @pg: page to deal with
+ *
+ * Takes care that @page has corresponding metadata in the tree, creates jnode
+ * for @page and captures it. On success 1 is returned.
+ */
+static int capture_anonymous_page(struct page *page)
+{
+       int result;
+
+       if (PageWriteback(page))
+               /* FIXME: do nothing? */
+               return 0;
+
+       result = capture_page_and_create_extent(page);
+       if (result == 0) {
+               result = 1;
+       } else
+               warning("nikita-3329",
+                               "Cannot capture anon page: %i", result);
+
+       return result;
+}
+
+/**
+ * capture_anonymous_pages - find and capture pages dirtied via mmap
+ * @mapping: address space where to look for pages
+ * @index: start index
+ * @to_capture: maximum number of pages to capture
+ *
+ * Looks for pages tagged REISER4_MOVED starting from the *@index-th page,
+ * captures (involves into atom) them, returns number of captured pages,
+ * updates @index to next page after the last captured one.
+ */
+static int
+capture_anonymous_pages(struct address_space *mapping, pgoff_t *index,
+                       unsigned int to_capture)
+{
+       int result;
+       struct pagevec pvec;
+       unsigned int i, count;
+       int nr;
+
+       pagevec_init(&pvec, 0);
+       count = min(pagevec_space(&pvec), to_capture);
+       nr = 0;
+
+       /* find pages tagged MOVED */
+       write_lock_irq(&mapping->tree_lock);
+       pvec.nr = radix_tree_gang_lookup_tag(&mapping->page_tree,
+                                            (void **)pvec.pages, *index, count,
+                                            PAGECACHE_TAG_REISER4_MOVED);
+       if (pagevec_count(&pvec) == 0) {
+               /*
+                * there are no pages tagged MOVED in mapping->page_tree
+                * starting from *index
+                */
+               write_unlock_irq(&mapping->tree_lock);
+               *index = (pgoff_t)-1;
+               return 0;
+       }
+
+       /* clear MOVED tag for all found pages */
+       for (i = 0; i < pagevec_count(&pvec); i++) {
+               void *p;
+
+               page_cache_get(pvec.pages[i]);
+               p = radix_tree_tag_clear(&mapping->page_tree, pvec.pages[i]->index,
+                                        PAGECACHE_TAG_REISER4_MOVED);
+               assert("vs-49", p == pvec.pages[i]);
+       }
+       write_unlock_irq(&mapping->tree_lock);
+
+
+       *index = pvec.pages[i - 1]->index + 1;
+
+       for (i = 0; i < pagevec_count(&pvec); i++) {
+               /*
+                * tag PAGECACHE_TAG_REISER4_MOVED will be cleared by
+                * reiser4_set_page_dirty_internal which is called when jnode is
+                * captured
+                */
+               result = capture_anonymous_page(pvec.pages[i]);
+               if (result == 1)
+                       nr++;
+               else {
+                       if (result < 0) {
+                               warning("vs-1454",
+                                       "failed to capture page: "
+                                       "result=%d, captured=%d)\n",
+                                       result, i);
+
+                               /*
+                                * set MOVED tag to all pages which left not
+                                * captured
+                                */
+                               write_lock_irq(&mapping->tree_lock);
+                               for (; i < pagevec_count(&pvec); i ++) {
+                                       radix_tree_tag_set(&mapping->page_tree,
+                                                          pvec.pages[i]->index,
+                                                          PAGECACHE_TAG_REISER4_MOVED);
+                               }
+                               write_unlock_irq(&mapping->tree_lock);
+
+                               pagevec_release(&pvec);
+                               return result;
+                       } else {
+                               /*
+                                * result == 0. capture_anonymous_page returns
+                                * 0 for Writeback-ed page. Set MOVED tag on
+                                * that page
+                                */
+                               write_lock_irq(&mapping->tree_lock);
+                               radix_tree_tag_set(&mapping->page_tree,
+                                                  pvec.pages[i]->index,
+                                                  PAGECACHE_TAG_REISER4_MOVED);
+                               write_unlock_irq(&mapping->tree_lock);
+                               if (i == 0)
+                                       *index = pvec.pages[0]->index;
+                               else
+                                       *index = pvec.pages[i - 1]->index + 1;
+                       }
+               }
+       }
+       pagevec_release(&pvec);
+       return nr;
+}
+
+/**
+ * capture_anonymous_jnodes - find and capture anonymous jnodes
+ * @mapping: address space where to look for jnodes
+ * @from: start index
+ * @to: end index
+ * @to_capture: maximum number of jnodes to capture
+ *
+ * Looks for jnodes tagged EFLUSH_TAG_ANONYMOUS in inode's tree of jnodes in
+ * the range of indexes @from-@to and captures them, returns number of captured
+ * jnodes, updates @from to next jnode after the last captured one.
+ */
+static int
+capture_anonymous_jnodes(struct address_space *mapping,
+                        pgoff_t *from, pgoff_t to, int to_capture)
+{
+       *from = to;
+       return 0;
+}
+
+/*
+ * Commit atom of the jnode of a page.
+ */
+static int sync_page(struct page *page)
+{
+       int result;
+       do {
+               jnode *node;
+               txn_atom *atom;
+
+               lock_page(page);
+               node = jprivate(page);
+               if (node != NULL) {
+                       spin_lock_jnode(node);
+                       atom = jnode_get_atom(node);
+                       spin_unlock_jnode(node);
+               } else
+                       atom = NULL;
+               unlock_page(page);
+               result = reiser4_sync_atom(atom);
+       } while (result == -E_REPEAT);
+       /*
+        * ZAM-FIXME-HANS: document the logic of this loop, is it just to
+        * handle the case where more pages get added to the atom while we are
+        * syncing it?
+        */
+       assert("nikita-3485", ergo(result == 0,
+                                  get_current_context()->trans->atom == NULL));
+       return result;
+}
+
+/*
+ * Commit atoms of pages on @pages list.
+ * call sync_page for each page from mapping's page tree
+ */
+static int sync_page_list(struct inode *inode)
+{
+       int result;
+       struct address_space *mapping;
+       unsigned long from;     /* start index for radix_tree_gang_lookup */
+       unsigned int found;     /* return value for radix_tree_gang_lookup */
+
+       mapping = inode->i_mapping;
+       from = 0;
+       result = 0;
+       read_lock_irq(&mapping->tree_lock);
+       while (result == 0) {
+               struct page *page;
+
+               found =
+                   radix_tree_gang_lookup(&mapping->page_tree, (void **)&page,
+                                          from, 1);
+               assert("", found < 2);
+               if (found == 0)
+                       break;
+
+               /* page may not leave radix tree because it is protected from truncating by inode->i_mutex locked by
+                  sys_fsync */
+               page_cache_get(page);
+               read_unlock_irq(&mapping->tree_lock);
+
+               from = page->index + 1;
+
+               result = sync_page(page);
+
+               page_cache_release(page);
+               read_lock_irq(&mapping->tree_lock);
+       }
+
+       read_unlock_irq(&mapping->tree_lock);
+       return result;
+}
+
+static int commit_file_atoms(struct inode *inode)
+{
+       int result;
+       unix_file_info_t *uf_info;
+
+       uf_info = unix_file_inode_data(inode);
+
+       get_exclusive_access(uf_info);
+       /*
+        * find what items file is made from
+        */
+       result = find_file_state(inode, uf_info);
+       drop_exclusive_access(uf_info);
+       if (result != 0)
+               return result;
+
+       /*
+        * file state cannot change because we are under ->i_mutex
+        */
+       switch (uf_info->container) {
+       case UF_CONTAINER_EXTENTS:
+               /* find_file_state might open join an atom */
+               reiser4_txn_restart_current();
+               result =
+                   /*
+                    * when we are called by
+                    * filemap_fdatawrite->
+                    *    do_writepages()->
+                    *       reiser4_writepages()
+                    *
+                    * inode->i_mapping->dirty_pages are spices into
+                    * ->io_pages, leaving ->dirty_pages dirty.
+                    *
+                    * When we are called from
+                    * reiser4_fsync()->sync_unix_file(), we have to
+                    * commit atoms of all pages on the ->dirty_list.
+                    *
+                    * So for simplicity we just commit ->io_pages and
+                    * ->dirty_pages.
+                    */
+                   sync_page_list(inode);
+               break;
+       case UF_CONTAINER_TAILS:
+               /*
+                * NOTE-NIKITA probably we can be smarter for tails. For now
+                * just commit all existing atoms.
+                */
+               result = txnmgr_force_commit_all(inode->i_sb, 0);
+               break;
+       case UF_CONTAINER_EMPTY:
+               result = 0;
+               break;
+       case UF_CONTAINER_UNKNOWN:
+       default:
+               result = -EIO;
+               break;
+       }
+
+       /*
+        * commit current transaction: there can be captured nodes from
+        * find_file_state() and finish_conversion().
+        */
+       reiser4_txn_restart_current();
+       return result;
+}
+
+/**
+ * writepages_unix_file - writepages of struct address_space_operations
+ * @mapping:
+ * @wbc:
+ *
+ * This captures anonymous pages and anonymous jnodes. Anonymous pages are
+ * pages which are dirtied via mmapping. Anonymous jnodes are ones which were
+ * created by reiser4_writepage.
+ */
+int writepages_unix_file(struct address_space *mapping,
+                    struct writeback_control *wbc)
+{
+       int result;
+       unix_file_info_t *uf_info;
+       pgoff_t pindex, jindex, nr_pages;
+       long to_capture;
+       struct inode *inode;
+
+       inode = mapping->host;
+       if (!has_anonymous_pages(inode)) {
+               result = 0;
+               goto end;
+       }
+       jindex = pindex = wbc->range_start >> PAGE_CACHE_SHIFT;
+       result = 0;
+       nr_pages =
+           (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       uf_info = unix_file_inode_data(inode);
+
+       do {
+               reiser4_context *ctx;
+
+               if (wbc->sync_mode != WB_SYNC_ALL)
+                       to_capture = min(wbc->nr_to_write, CAPTURE_APAGE_BURST);
+               else
+                       to_capture = CAPTURE_APAGE_BURST;
+
+               ctx = reiser4_init_context(inode->i_sb);
+               if (IS_ERR(ctx)) {
+                       result = PTR_ERR(ctx);
+                       break;
+               }
+               /* avoid recursive calls to ->sync_inodes */
+               ctx->nobalance = 1;
+               assert("zam-760", lock_stack_isclean(get_current_lock_stack()));
+               assert("", LOCK_CNT_NIL(inode_sem_w));
+               assert("", LOCK_CNT_NIL(inode_sem_r));
+
+               reiser4_txn_restart_current();
+
+               /* we have to get nonexclusive access to the file */
+               if (get_current_context()->entd) {
+                       /*
+                        * use nonblocking version of nonexclusive_access to
+                        * avoid deadlock which might look like the following:
+                        * process P1 holds NEA on file F1 and called entd to
+                        * reclaim some memory. Entd works for P1 and is going
+                        * to capture pages of file F2. To do that entd has to
+                        * get NEA to F2. F2 is held by process P2 which also
+                        * called entd. But entd is serving P1 at the moment
+                        * and P2 has to wait. Process P3 trying to get EA to
+                        * file F2. Existence of pending EA request to file F2
+                        * makes impossible for entd to get NEA to file
+                        * F2. Neither of these process can continue. Using
+                        * nonblocking version of gettign NEA is supposed to
+                        * avoid this deadlock.
+                        */
+                       if (try_to_get_nonexclusive_access(uf_info) == 0) {
+                               result = RETERR(-EBUSY);
+                               reiser4_exit_context(ctx);
+                               break;
+                       }
+               } else
+                       get_nonexclusive_access(uf_info);
+
+               while (to_capture > 0) {
+                       pgoff_t start;
+
+                       assert("vs-1727", jindex <= pindex);
+                       if (pindex == jindex) {
+                               start = pindex;
+                               result =
+                                   capture_anonymous_pages(inode->i_mapping,
+                                                           &pindex,
+                                                           to_capture);
+                               if (result <= 0)
+                                       break;
+                               to_capture -= result;
+                               wbc->nr_to_write -= result;
+                               if (start + result == pindex) {
+                                       jindex = pindex;
+                                       continue;
+                               }
+                               if (to_capture <= 0)
+                                       break;
+                       }
+                       /* deal with anonymous jnodes between jindex and pindex */
+                       result =
+                           capture_anonymous_jnodes(inode->i_mapping, &jindex,
+                                                    pindex, to_capture);
+                       if (result < 0)
+                               break;
+                       to_capture -= result;
+                       get_current_context()->nr_captured += result;
+
+                       if (jindex == (pgoff_t) - 1) {
+                               assert("vs-1728", pindex == (pgoff_t) - 1);
+                               break;
+                       }
+               }
+               if (to_capture <= 0)
+                       /* there may be left more pages */
+                       __mark_inode_dirty(inode, I_DIRTY_PAGES);
+
+               drop_nonexclusive_access(uf_info);
+               if (result < 0) {
+                       /* error happened */
+                       reiser4_exit_context(ctx);
+                       return result;
+               }
+               if (wbc->sync_mode != WB_SYNC_ALL) {
+                       reiser4_exit_context(ctx);
+                       return 0;
+               }
+               result = commit_file_atoms(inode);
+               reiser4_exit_context(ctx);
+               if (pindex >= nr_pages && jindex == pindex)
+                       break;
+       } while (1);
+
+      end:
+       if (is_in_reiser4_context()) {
+               if (get_current_context()->nr_captured >= CAPTURE_APAGE_BURST) {
+                       /*
+                        * there are already pages to flush, flush them out, do
+                        * not delay until end of reiser4_sync_inodes
+                        */
+                       reiser4_writeout(inode->i_sb, wbc);
+                       get_current_context()->nr_captured = 0;
+               }
+       }
+       return result;
+}
+
+/*
+ * ->sync() method for unix file.
+ *
+ * We are trying to be smart here. Instead of committing all atoms (original
+ * solution), we scan dirty pages of this file and commit all atoms they are
+ * part of.
+ *
+ * Situation is complicated by anonymous pages: i.e., extent-less pages
+ * dirtied through mmap. Fortunately sys_fsync() first calls
+ * filemap_fdatawrite() that will ultimately call reiser4_writepages(), insert
+ * all missing extents and capture anonymous pages.
+ */
+int sync_unix_file(struct file *file, struct dentry *dentry, int datasync)
+{
+       reiser4_context *ctx;
+       txn_atom *atom;
+       reiser4_block_nr reserve;
+
+       ctx = reiser4_init_context(dentry->d_inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       reserve = estimate_update_common(dentry->d_inode);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT)) {
+               reiser4_exit_context(ctx);
+               return RETERR(-ENOSPC);
+       }
+       write_sd_by_inode_common(dentry->d_inode);
+
+       atom = get_current_atom_locked();
+       spin_lock_txnh(ctx->trans);
+       force_commit_atom(ctx->trans);
+       reiser4_exit_context(ctx);
+       return 0;
+}
+
+/**
+ * readpage_unix_file_nolock - readpage of struct address_space_operations
+ * @file:
+ * @page:
+ *
+ * Compose a key and search for item containing information about @page
+ * data. If item is found - its readpage method is called.
+ */
+int readpage_unix_file(struct file *file, struct page *page)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *inode;
+       reiser4_key key;
+       item_plugin *iplug;
+       hint_t *hint;
+       lock_handle *lh;
+       coord_t *coord;
+
+       assert("vs-1062", PageLocked(page));
+       assert("vs-976", !PageUptodate(page));
+       assert("vs-1061", page->mapping && page->mapping->host);
+
+       if (page->mapping->host->i_size <= page_offset(page)) {
+               /* page is out of file already */
+               unlock_page(page);
+               return -EINVAL;
+       }
+
+       inode = page->mapping->host;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx)) {
+               unlock_page(page);
+               return PTR_ERR(ctx);
+       }
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL) {
+               unlock_page(page);
+               reiser4_exit_context(ctx);
+               return RETERR(-ENOMEM);
+       }
+
+       result = load_file_hint(file, hint);
+       if (result) {
+               kfree(hint);
+               unlock_page(page);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+       lh = &hint->lh;
+
+       /* get key of first byte of the page */
+       key_by_inode_and_offset_common(inode, page_offset(page), &key);
+
+       /* look for file metadata corresponding to first byte of page */
+       page_cache_get(page);
+       unlock_page(page);
+       result = find_file_item(hint, &key, ZNODE_READ_LOCK, inode);
+       lock_page(page);
+       page_cache_release(page);
+
+       if (page->mapping == NULL) {
+               /*
+                * readpage allows truncate to run concurrently. Page was
+                * truncated while it was not locked
+                */
+               done_lh(lh);
+               kfree(hint);
+               unlock_page(page);
+               reiser4_txn_restart(ctx);
+               reiser4_exit_context(ctx);
+               return -EINVAL;
+       }
+
+       if (result != CBK_COORD_FOUND || hint->ext_coord.coord.between != AT_UNIT) {
+               if (result == CBK_COORD_FOUND &&
+                   hint->ext_coord.coord.between != AT_UNIT)
+                       /* file is truncated */
+                       result = -EINVAL;
+               done_lh(lh);
+               kfree(hint);
+               unlock_page(page);
+               reiser4_txn_restart(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       /*
+        * item corresponding to page is found. It can not be removed because
+        * znode lock is held
+        */
+       if (PageUptodate(page)) {
+               done_lh(lh);
+               kfree(hint);
+               unlock_page(page);
+               reiser4_txn_restart(ctx);
+               reiser4_exit_context(ctx);
+               return 0;
+       }
+
+       coord = &hint->ext_coord.coord;
+       result = zload(coord->node);
+       if (result) {
+               done_lh(lh);
+               kfree(hint);
+               unlock_page(page);
+               reiser4_txn_restart(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       validate_extended_coord(&hint->ext_coord, page_offset(page));
+
+       if (!coord_is_existing_unit(coord)) {
+               /* this indicates corruption */
+               warning("vs-280",
+                       "Looking for page %lu of file %llu (size %lli). "
+                       "No file items found (%d). File is corrupted?\n",
+                       page->index, (unsigned long long)get_inode_oid(inode),
+                       inode->i_size, result);
+               zrelse(coord->node);
+               done_lh(lh);
+               kfree(hint);
+               unlock_page(page);
+               reiser4_txn_restart(ctx);
+               reiser4_exit_context(ctx);
+               return RETERR(-EIO);
+       }
+
+       /*
+        * get plugin of found item or use plugin if extent if there are no
+        * one
+        */
+       iplug = item_plugin_by_coord(coord);
+       if (iplug->s.file.readpage)
+               result = iplug->s.file.readpage(coord, page);
+       else
+               result = RETERR(-EINVAL);
+
+       if (!result) {
+               set_key_offset(&key,
+                              (loff_t) (page->index + 1) << PAGE_CACHE_SHIFT);
+               /* FIXME should call reiser4_set_hint() */
+               reiser4_unset_hint(hint);
+       } else {
+               unlock_page(page);
+               reiser4_unset_hint(hint);
+       }
+       assert("vs-979",
+              ergo(result == 0, (PageLocked(page) || PageUptodate(page))));
+       assert("vs-9791", ergo(result != 0, !PageLocked(page)));
+
+       zrelse(coord->node);
+       done_lh(lh);
+
+       save_file_hint(file, hint);
+       kfree(hint);
+
+       /*
+        * FIXME: explain why it is needed. HINT: page allocation in write can
+        * not be done when atom is not NULL because reiser4_writepage can not
+        * kick entd and have to eflush
+        */
+       reiser4_txn_restart(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+struct uf_readpages_context {
+       lock_handle lh;
+       coord_t coord;
+};
+
+/* A callback function for readpages_unix_file/read_cache_pages.
+ * If the file is build of tails, then return error (-ENOENT).
+ *
+ * @data -- a pointer to reiser4_readpages_context object,
+ *            to save the twig lock and the coord between
+ *            read_cache_page iterations.
+ * @page -- page to start read.
+ */
+static int uf_readpages_filler(void * data, struct page * page)
+{
+       struct uf_readpages_context *rc = data;
+       jnode * node;
+       int ret = 0;
+       reiser4_extent *ext;
+       __u64 ext_index;
+       int cbk_done = 0;
+       struct address_space * mapping = page->mapping;
+
+       if (PageUptodate(page)) {
+               unlock_page(page);
+               return 0;
+       }
+       if (rc->lh.node == 0) {
+               /* no twig lock  - have to do tree search. */
+               reiser4_key key;
+       repeat:
+               unlock_page(page);
+               key_by_inode_and_offset_common(
+                       mapping->host, page_offset(page), &key);
+               ret = coord_by_key(
+                       &get_super_private(mapping->host->i_sb)->tree,
+                       &key, &rc->coord, &rc->lh,
+                       ZNODE_READ_LOCK, FIND_EXACT,
+                       TWIG_LEVEL, TWIG_LEVEL, CBK_UNIQUE, NULL);
+               if (ret)
+                       return ret;
+               lock_page(page);
+               cbk_done = 1;
+       }
+       ret = zload(rc->coord.node);
+       if (ret) {
+               unlock_page(page);
+               return ret;
+       }
+       if (!coord_is_existing_item(&rc->coord) ||
+           !item_is_extent(&rc->coord)) {
+               zrelse(rc->coord.node);
+               unlock_page(page);
+               return RETERR(-EIO);
+       }
+       ext = extent_by_coord(&rc->coord);
+       ext_index = extent_unit_index(&rc->coord);
+       if (page->index < ext_index ||
+           page->index >= ext_index + extent_get_width(ext)) {
+               /* the page index doesn't belong to the extent unit
+                  which the coord points to - release the lock and
+                  repeat with tree search. */
+               zrelse(rc->coord.node);
+               done_lh(&rc->lh);
+               /* we can be here after a CBK call only in case of
+                  corruption of the tree or the tree lookup algorithm bug. */
+               if (unlikely(cbk_done)) {
+                       unlock_page(page);
+                       return RETERR(-EIO);
+               }
+               goto repeat;
+       }
+       node = jnode_of_page(page);
+       if (unlikely(IS_ERR(node))) {
+               zrelse(rc->coord.node);
+               unlock_page(page);
+               return PTR_ERR(node);
+       }
+       ret = reiser4_do_readpage_extent(ext, page->index - ext_index, page);
+       jput(node);
+       zrelse(rc->coord.node);
+       if (ret)
+               unlock_page(page);
+       return ret;
+}
+
+/**
+ * readpages_unix_file - called by the readahead code, starts reading for each
+ * page of given list of pages
+ */
+int readpages_unix_file(
+       struct file *file, struct address_space *mapping,
+       struct list_head *pages, unsigned nr_pages)
+{
+       reiser4_context *ctx;
+       struct uf_readpages_context rc;
+       int ret;
+
+       ctx = reiser4_init_context(mapping->host->i_sb);
+       if (IS_ERR(ctx)) {
+               put_pages_list(pages);
+               return PTR_ERR(ctx);
+       }
+       init_lh(&rc.lh);
+       ret = read_cache_pages(mapping, pages,  uf_readpages_filler, &rc);
+       done_lh(&rc.lh);
+       context_set_commit_async(ctx);
+       /* close the transaction to protect further page allocation from deadlocks */
+       reiser4_txn_restart(ctx);
+       reiser4_exit_context(ctx);
+       return ret;
+}
+
+static reiser4_block_nr unix_file_estimate_read(struct inode *inode,
+                                               loff_t count UNUSED_ARG)
+{
+       /* We should reserve one block, because of updating of the stat data
+          item */
+       assert("vs-1249",
+              inode_file_plugin(inode)->estimate.update ==
+              estimate_update_common);
+       return estimate_update_common(inode);
+}
+
+/* this is called with nonexclusive access obtained, file's container can not change */
+static ssize_t read_file(hint_t *hint, struct file *file,      /* file to read from to */
+                        char __user *buf,      /* address of user-space buffer */
+                        size_t count,  /* number of bytes to read */
+                        loff_t *off)
+{
+       int result;
+       struct inode *inode;
+       flow_t flow;
+       int (*read_f) (struct file *, flow_t *, hint_t *);
+       coord_t *coord;
+       znode *loaded;
+
+       inode = file->f_dentry->d_inode;
+
+       /* build flow */
+       assert("vs-1250",
+              inode_file_plugin(inode)->flow_by_inode ==
+              flow_by_inode_unix_file);
+       result =
+           flow_by_inode_unix_file(inode, buf, 1 /* user space */ , count,
+                                   *off, READ_OP, &flow);
+       if (unlikely(result))
+               return result;
+
+       /* get seal and coord sealed with it from reiser4 private data
+          of struct file.  The coord will tell us where our last read
+          of this file finished, and the seal will help to determine
+          if that location is still valid.
+        */
+       coord = &hint->ext_coord.coord;
+       while (flow.length && result == 0) {
+               result =
+                       find_file_item(hint, &flow.key, ZNODE_READ_LOCK, inode);
+               if (cbk_errored(result))
+                       /* error happened */
+                       break;
+
+               if (coord->between != AT_UNIT) {
+                       /* there were no items corresponding to given offset */
+                       done_lh(hint->ext_coord.lh);
+                       break;
+               }
+
+               loaded = coord->node;
+               result = zload(loaded);
+               if (unlikely(result)) {
+                       done_lh(hint->ext_coord.lh);
+                       break;
+               }
+
+               if (hint->ext_coord.valid == 0)
+                       validate_extended_coord(&hint->ext_coord,
+                                               get_key_offset(&flow.key));
+
+               assert("vs-4", hint->ext_coord.valid == 1);
+               assert("vs-33", hint->ext_coord.lh == &hint->lh);
+               /* call item's read method */
+               read_f = item_plugin_by_coord(coord)->s.file.read;
+               result = read_f(file, &flow, hint);
+               zrelse(loaded);
+               done_lh(hint->ext_coord.lh);
+       }
+
+       return (count - flow.length) ? (count - flow.length) : result;
+}
+
+static ssize_t read_unix_file_container_tails(struct file*, char __user*, size_t, loff_t*);
+
+/**
+ * read_unix_file - read of struct file_operations
+ * @file: file to read from
+ * @buf: address of user-space buffer
+ * @read_amount: number of bytes to read
+ * @off: position in file to read from
+ *
+ * This is implementation of vfs's read method of struct file_operations for
+ * unix file plugin.
+ */
+ssize_t read_unix_file(struct file *file, char __user *buf, size_t read_amount,
+                      loff_t *off)
+{
+       reiser4_context *ctx;
+       ssize_t result;
+       struct inode *inode;
+       unix_file_info_t *uf_info;
+
+       if (unlikely(read_amount == 0))
+               return 0;
+
+       assert("umka-072", file != NULL);
+       assert("umka-074", off != NULL);
+       inode = file->f_dentry->d_inode;
+       assert("vs-972", !reiser4_inode_get_flag(inode, REISER4_NO_SD));
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       uf_info = unix_file_inode_data(inode);
+       if (uf_info->container == UF_CONTAINER_UNKNOWN) {
+               get_exclusive_access(uf_info);
+               result = find_file_state(inode, uf_info);
+               if (unlikely(result != 0))
+                       goto out;
+       } else
+               get_nonexclusive_access(uf_info);
+       result = reiser4_grab_space_force(unix_file_estimate_read(inode, read_amount),
+                                         BA_CAN_COMMIT);
+       if (unlikely(result != 0))
+               goto out;
+       if (uf_info->container == UF_CONTAINER_EXTENTS){
+               result = do_sync_read(file, buf, read_amount, off);
+       } else if (uf_info->container == UF_CONTAINER_TAILS ||
+                  reiser4_inode_get_flag(inode, REISER4_PART_IN_CONV) ||
+                  reiser4_inode_get_flag(inode, REISER4_PART_MIXED)) {
+               result = read_unix_file_container_tails(file, buf, read_amount, off);
+       } else {
+               assert("zam-1085", uf_info->container == UF_CONTAINER_EMPTY);
+               result = 0;
+       }
+out:
+       drop_access(uf_info);
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+static ssize_t read_unix_file_container_tails(
+       struct file *file, char __user *buf, size_t read_amount, loff_t *off)
+{
+       int result;
+       struct inode *inode;
+       hint_t *hint;
+       unix_file_info_t *uf_info;
+       size_t count, read, left;
+       loff_t size;
+
+       assert("umka-072", file != NULL);
+       assert("umka-074", off != NULL);
+       inode = file->f_dentry->d_inode;
+       assert("vs-972", !reiser4_inode_get_flag(inode, REISER4_NO_SD));
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL)
+               return RETERR(-ENOMEM);
+
+       result = load_file_hint(file, hint);
+       if (result) {
+               kfree(hint);
+               return result;
+       }
+
+       left = read_amount;
+       count = 0;
+       uf_info = unix_file_inode_data(inode);
+       while (left > 0) {
+               reiser4_txn_restart_current();
+               size = i_size_read(inode);
+               if (*off >= size)
+                       /* position to read from is past the end of file */
+                       break;
+               if (*off + left > size)
+                       left = size - *off;
+               /* faultin user page */
+               result = fault_in_pages_writeable(buf, left > PAGE_CACHE_SIZE ? PAGE_CACHE_SIZE : left);
+               if (result)
+                       return RETERR(-EFAULT);
+
+               read = read_file(hint, file, buf,
+                                left > PAGE_CACHE_SIZE ? PAGE_CACHE_SIZE : left,
+                                off);
+               if (read < 0) {
+                       result = read;
+                       break;
+               }
+               left -= read;
+               buf += read;
+
+               /* update position in a file */
+               *off += read;
+               /* total number of read bytes */
+               count += read;
+       }
+       done_lh(&hint->lh);
+       save_file_hint(file, hint);
+       kfree(hint);
+       if (count)
+               file_accessed(file);
+       /* return number of read bytes or error code if nothing is read */
+       return count ? count : result;
+}
+
+/* This function takes care about @file's pages. First of all it checks if
+   filesystems readonly and if so gets out. Otherwise, it throws out all
+   pages of file if it was mapped for read and going to be mapped for write
+   and consists of tails. This is done in order to not manage few copies
+   of the data (first in page cache and second one in tails them selves)
+   for the case of mapping files consisting tails.
+
+   Here also tail2extent conversion is performed if it is allowed and file
+   is going to be written or mapped for write. This functions may be called
+   from write_unix_file() or mmap_unix_file(). */
+static int check_pages_unix_file(struct file *file, struct inode *inode)
+{
+       reiser4_invalidate_pages(inode->i_mapping, 0,
+                                (inode->i_size + PAGE_CACHE_SIZE -
+                                 1) >> PAGE_CACHE_SHIFT, 0);
+       return unpack(file, inode, 0 /* not forever */ );
+}
+
+/**
+ * mmap_unix_file - mmap of struct file_operations
+ * @file: file to mmap
+ * @vma:
+ *
+ * This is implementation of vfs's mmap method of struct file_operations for
+ * unix file plugin. It converts file to extent if necessary. Sets
+ * reiser4_inode's flag - REISER4_HAS_MMAP.
+ */
+int mmap_unix_file(struct file *file, struct vm_area_struct *vma)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *inode;
+       unix_file_info_t *uf_info;
+       reiser4_block_nr needed;
+
+       inode = file->f_dentry->d_inode;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       uf_info = unix_file_inode_data(inode);
+
+       get_exclusive_access_careful(uf_info, inode);
+
+       if (!IS_RDONLY(inode) && (vma->vm_flags & (VM_MAYWRITE | VM_SHARED))) {
+               /*
+                * we need file built of extent items. If it is still built of
+                * tail items we have to convert it. Find what items the file
+                * is built of
+                */
+               result = find_file_state(inode, uf_info);
+               if (result != 0) {
+                       drop_exclusive_access(uf_info);
+                       reiser4_exit_context(ctx);
+                       return result;
+               }
+
+               assert("vs-1648", (uf_info->container == UF_CONTAINER_TAILS ||
+                                  uf_info->container == UF_CONTAINER_EXTENTS ||
+                                  uf_info->container == UF_CONTAINER_EMPTY));
+               if (uf_info->container == UF_CONTAINER_TAILS) {
+                       /*
+                        * invalidate all pages and convert file from tails to
+                        * extents
+                        */
+                       result = check_pages_unix_file(file, inode);
+                       if (result) {
+                               drop_exclusive_access(uf_info);
+                               reiser4_exit_context(ctx);
+                               return result;
+                       }
+               }
+       }
+
+       /*
+        * generic_file_mmap will do update_atime. Grab space for stat data
+        * update.
+        */
+       needed = inode_file_plugin(inode)->estimate.update(inode);
+       result = reiser4_grab_space_force(needed, BA_CAN_COMMIT);
+       if (result) {
+               drop_exclusive_access(uf_info);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       result = generic_file_mmap(file, vma);
+       if (result == 0) {
+               /* mark file as having mapping. */
+               reiser4_inode_set_flag(inode, REISER4_HAS_MMAP);
+       }
+
+       drop_exclusive_access(uf_info);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/**
+ * find_first_item
+ * @inode:
+ *
+ * Finds file item which is responsible for first byte in the file.
+ */
+static int find_first_item(struct inode *inode)
+{
+       coord_t coord;
+       lock_handle lh;
+       reiser4_key key;
+       int result;
+
+       coord_init_zero(&coord);
+       init_lh(&lh);
+       inode_file_plugin(inode)->key_by_inode(inode, 0, &key);
+       result = find_file_item_nohint(&coord, &lh, &key, ZNODE_READ_LOCK,
+                                      inode);
+       if (result == CBK_COORD_FOUND) {
+               if (coord.between == AT_UNIT) {
+                       result = zload(coord.node);
+                       if (result == 0) {
+                               result = item_id_by_coord(&coord);
+                               zrelse(coord.node);
+                               if (result != EXTENT_POINTER_ID &&
+                                   result != FORMATTING_ID)
+                                       result = RETERR(-EIO);
+                       }
+               } else
+                       result = RETERR(-EIO);
+       }
+       done_lh(&lh);
+       return result;
+}
+
+/**
+ * open_unix_file
+ * @inode:
+ * @file:
+ *
+ * If filesystem is not readonly - complete uncompleted tail conversion if
+ * there was one
+ */
+int open_unix_file(struct inode *inode, struct file *file)
+{
+       int result;
+       reiser4_context *ctx;
+       unix_file_info_t *uf_info;
+
+       if (IS_RDONLY(inode))
+               return 0;
+
+       if (!reiser4_inode_get_flag(inode, REISER4_PART_MIXED))
+               return 0;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       uf_info = unix_file_inode_data(inode);
+
+       get_exclusive_access_careful(uf_info, inode);
+
+       if (!reiser4_inode_get_flag(inode, REISER4_PART_MIXED)) {
+               /*
+                * other process completed the conversion
+                */
+               drop_exclusive_access(uf_info);
+               reiser4_exit_context(ctx);
+               return 0;
+       }
+
+       /*
+        * file left in semi converted state after unclean shutdown or another
+        * thread is doing conversion and dropped exclusive access which doing
+        * balance dirty pages. Complete the conversion
+        */
+       result = find_first_item(inode);
+       if (result == EXTENT_POINTER_ID)
+               /*
+                * first item is extent, therefore there was incomplete
+                * tail2extent conversion. Complete it
+                */
+               result = tail2extent(unix_file_inode_data(inode));
+       else if (result == FORMATTING_ID)
+               /*
+                * first item is formatting item, therefore there was
+                * incomplete extent2tail conversion. Complete it
+                */
+               result = extent2tail(unix_file_inode_data(inode));
+       else
+               result = -EIO;
+
+       assert("vs-1712",
+              ergo(result == 0,
+                   (!reiser4_inode_get_flag(inode, REISER4_PART_MIXED) &&
+                    !reiser4_inode_get_flag(inode, REISER4_PART_IN_CONV))));
+       drop_exclusive_access(uf_info);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+#define NEITHER_OBTAINED 0
+#define EA_OBTAINED 1
+#define NEA_OBTAINED 2
+
+static void drop_access(unix_file_info_t *uf_info)
+{
+       if (uf_info->exclusive_use)
+               drop_exclusive_access(uf_info);
+       else
+               drop_nonexclusive_access(uf_info);
+}
+
+#define debug_wuf(format, ...) printk("%s: %d: %s: " format "\n", \
+                             __FILE__, __LINE__, __FUNCTION__, ## __VA_ARGS__)
+
+/**
+ * write_unix_file - write of struct file_operations
+ * @file: file to write to
+ * @buf: address of user-space buffer
+ * @write_amount: number of bytes to write
+ * @off: position in file to write to
+ *
+ * This is implementation of vfs's write method of struct file_operations for
+ * unix file plugin.
+ */
+ssize_t write_unix_file(struct file *file, const char __user *buf,
+                       size_t count, loff_t *pos)
+{
+       int result;
+       reiser4_context *ctx;
+       struct inode *inode;
+       unix_file_info_t *uf_info;
+       ssize_t written;
+       int try_free_space;
+       int to_write = PAGE_CACHE_SIZE * WRITE_GRANULARITY;
+       size_t left;
+       ssize_t (*write_op)(struct file *, const char __user *, size_t,
+                           loff_t *pos);
+       int ea;
+       loff_t new_size;
+
+       inode = file->f_dentry->d_inode;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       mutex_lock(&inode->i_mutex);
+
+       assert("vs-947", !reiser4_inode_get_flag(inode, REISER4_NO_SD));
+       assert("vs-9471", (!reiser4_inode_get_flag(inode, REISER4_PART_MIXED)));
+
+       /* check amount of bytes to write and writing position */
+       result = generic_write_checks(file, pos, &count, 0);
+       if (result) {
+               mutex_unlock(&inode->i_mutex);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       result = remove_suid(file->f_dentry);
+       if (result) {
+               mutex_unlock(&inode->i_mutex);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       uf_info = unix_file_inode_data(inode);
+
+       current->backing_dev_info = inode->i_mapping->backing_dev_info;
+       written = 0;
+       try_free_space = 0;
+       left = count;
+       ea = NEITHER_OBTAINED;
+
+       new_size = i_size_read(inode);
+       if (*pos + count > new_size)
+               new_size = *pos + count;
+
+       while (left) {
+               if (left < to_write)
+                       to_write = left;
+
+               if (uf_info->container == UF_CONTAINER_EMPTY) {
+                       get_exclusive_access(uf_info);
+                       ea = EA_OBTAINED;
+                       if (uf_info->container != UF_CONTAINER_EMPTY) {
+                               /* file is made not empty by another process */
+                               drop_exclusive_access(uf_info);
+                               ea = NEITHER_OBTAINED;
+                               continue;
+                       }
+               } else if (uf_info->container == UF_CONTAINER_UNKNOWN) {
+                       /*
+                        * get exclusive access directly just to not have to
+                        * re-obtain it if file will appear empty
+                        */
+                       get_exclusive_access(uf_info);
+                       ea = EA_OBTAINED;
+                       result = find_file_state(inode, uf_info);
+                       if (result) {
+                               drop_exclusive_access(uf_info);
+                               ea = NEITHER_OBTAINED;
+                               break;
+                       }
+               } else {
+                       get_nonexclusive_access(uf_info);
+                       ea = NEA_OBTAINED;
+               }
+
+               /* either EA or NEA is obtained. Choose item write method */
+               if (uf_info->container == UF_CONTAINER_EXTENTS) {
+                       /* file is built of extent items */
+                       write_op = reiser4_write_extent;
+               } else if (uf_info->container == UF_CONTAINER_EMPTY) {
+                       /* file is empty */
+                       if (should_have_notail(uf_info, new_size))
+                               write_op = reiser4_write_extent;
+                       else
+                               write_op = reiser4_write_tail;
+               } else {
+                       /* file is built of tail items */
+                       if (should_have_notail(uf_info, new_size)) {
+                               if (ea == NEA_OBTAINED) {
+                                       drop_nonexclusive_access(uf_info);
+                                       get_exclusive_access(uf_info);
+                                       ea = EA_OBTAINED;
+                               }
+                               if (uf_info->container == UF_CONTAINER_TAILS) {
+                                       /*
+                                        * if file is being convered by another
+                                        * process - wait until it completes
+                                        */
+                                       while (1) {
+                                               if (reiser4_inode_get_flag(inode,
+                                                                          REISER4_PART_IN_CONV)) {
+                                                       drop_exclusive_access(uf_info);
+                                                       schedule();
+                                                       get_exclusive_access(uf_info);
+                                                       continue;
+                                               }
+                                               break;
+                                       }
+                                       if (uf_info->container ==  UF_CONTAINER_TAILS) {
+                                               result = tail2extent(uf_info);
+                                               if (result)
+                                                       break;
+                                       }
+                               }
+                               drop_exclusive_access(uf_info);
+                               ea = NEITHER_OBTAINED;
+                               continue;
+                       }
+                       write_op = reiser4_write_tail;
+               }
+
+               written = write_op(file, buf, to_write, pos);
+               if (written == -ENOSPC && try_free_space) {
+                       drop_access(uf_info);
+                       txnmgr_force_commit_all(inode->i_sb, 0);
+                       try_free_space = 0;
+                       continue;
+               }
+               if (written < 0) {
+                       drop_access(uf_info);
+                       result = written;
+                       break;
+               }
+               /* something is written. */
+               if (uf_info->container == UF_CONTAINER_EMPTY) {
+                       assert("", ea == EA_OBTAINED);
+                       uf_info->container =
+                               (write_op == reiser4_write_extent) ?
+                               UF_CONTAINER_EXTENTS : UF_CONTAINER_TAILS;
+               } else {
+                       assert("", ergo(uf_info->container == UF_CONTAINER_EXTENTS,
+                                       write_op == reiser4_write_extent));
+                       assert("", ergo(uf_info->container == UF_CONTAINER_TAILS,
+                                       write_op == reiser4_write_tail));
+               }
+               if (*pos + written > inode->i_size)
+                       INODE_SET_FIELD(inode, i_size, *pos + written);
+               file_update_time(file);
+               result = reiser4_update_sd(inode);
+               if (result) {
+                       mutex_unlock(&inode->i_mutex);
+                       current->backing_dev_info = NULL;
+                       drop_access(uf_info);
+                       context_set_commit_async(ctx);
+                       reiser4_exit_context(ctx);
+                       return result;
+               }
+               drop_access(uf_info);
+               ea = NEITHER_OBTAINED;
+               reiser4_txn_restart(ctx);
+               current->journal_info = NULL;
+               /*
+                * tell VM how many pages were dirtied. Maybe number of pages
+                * which were dirty already should not be counted
+                */
+               balance_dirty_pages_ratelimited_nr(inode->i_mapping,
+                                                  (written + PAGE_CACHE_SIZE - 1) / PAGE_CACHE_SIZE);
+               current->journal_info = ctx;
+
+               left -= written;
+               buf += written;
+               *pos += written;
+       }
+
+       mutex_unlock(&inode->i_mutex);
+
+       if (result == 0 && ((file->f_flags & O_SYNC) || IS_SYNC(inode))) {
+               reiser4_txn_restart_current();
+               grab_space_enable();
+               result = sync_unix_file(file, file->f_dentry,
+                                       0 /* data and stat data */ );
+               if (result)
+                       warning("reiser4-7", "failed to sync file %llu",
+                               (unsigned long long)get_inode_oid(inode));
+       }
+
+       current->backing_dev_info = NULL;
+
+       reiser4_exit_context(ctx);
+
+       /*
+        * return number of written bytes or error code if nothing is
+        * written. Note, that it does not work correctly in case when
+        * sync_unix_file returns error
+        */
+       return (count - left) ? (count - left) : result;
+}
+
+/**
+ * release_unix_file - release of struct file_operations
+ * @inode: inode of released file
+ * @file: file to release
+ *
+ * Implementation of release method of struct file_operations for unix file
+ * plugin. If last reference to indode is released - convert all extent items
+ * into tail items if necessary. Frees reiser4 specific file data.
+ */
+int release_unix_file(struct inode *inode, struct file *file)
+{
+       reiser4_context *ctx;
+       unix_file_info_t *uf_info;
+       int result;
+       int in_reiser4;
+
+       in_reiser4 = is_in_reiser4_context();
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       result = 0;
+       if (in_reiser4 == 0) {
+               uf_info = unix_file_inode_data(inode);
+
+               get_exclusive_access_careful(uf_info, inode);
+               if (atomic_read(&file->f_dentry->d_count) == 1 &&
+                   uf_info->container == UF_CONTAINER_EXTENTS &&
+                   !should_have_notail(uf_info, inode->i_size) &&
+                   !rofs_inode(inode)) {
+                       result = extent2tail(uf_info);
+                       if (result != 0) {
+                               warning("nikita-3233",
+                                       "Failed (%d) to convert in %s (%llu)",
+                                       result, __FUNCTION__,
+                                       (unsigned long long)
+                                       get_inode_oid(inode));
+                       }
+               }
+               drop_exclusive_access(uf_info);
+       } else {
+               /*
+                  we are within reiser4 context already. How latter is
+                  possible? Simple:
+
+                  (gdb) bt
+                  #0  get_exclusive_access ()
+                  #2  0xc01e56d3 in release_unix_file ()
+                  #3  0xc01c3643 in reiser4_release ()
+                  #4  0xc014cae0 in __fput ()
+                  #5  0xc013ffc3 in remove_vm_struct ()
+                  #6  0xc0141786 in exit_mmap ()
+                  #7  0xc0118480 in mmput ()
+                  #8  0xc0133205 in oom_kill ()
+                  #9  0xc01332d1 in out_of_memory ()
+                  #10 0xc013bc1d in try_to_free_pages ()
+                  #11 0xc013427b in __alloc_pages ()
+                  #12 0xc013f058 in do_anonymous_page ()
+                  #13 0xc013f19d in do_no_page ()
+                  #14 0xc013f60e in handle_mm_fault ()
+                  #15 0xc01131e5 in do_page_fault ()
+                  #16 0xc0104935 in error_code ()
+                  #17 0xc025c0c6 in __copy_to_user_ll ()
+                  #18 0xc01d496f in reiser4_read_tail ()
+                  #19 0xc01e4def in read_unix_file ()
+                  #20 0xc01c3504 in reiser4_read ()
+                  #21 0xc014bd4f in vfs_read ()
+                  #22 0xc014bf66 in sys_read ()
+                */
+               warning("vs-44", "out of memory?");
+       }
+
+       reiser4_free_file_fsdata(file);
+
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+static void set_file_notail(struct inode *inode)
+{
+       reiser4_inode *state;
+       formatting_plugin *tplug;
+
+       state = reiser4_inode_data(inode);
+       tplug = formatting_plugin_by_id(NEVER_TAILS_FORMATTING_ID);
+       force_plugin_pset(inode, PSET_FORMATTING, (reiser4_plugin *)tplug);
+}
+
+/* if file is built of tails - convert it to extents */
+static int unpack(struct file *filp, struct inode *inode, int forever)
+{
+       int result = 0;
+       unix_file_info_t *uf_info;
+
+       uf_info = unix_file_inode_data(inode);
+       assert("vs-1628", ea_obtained(uf_info));
+
+       result = find_file_state(inode, uf_info);
+       if (result)
+               return result;
+       assert("vs-1074", uf_info->container != UF_CONTAINER_UNKNOWN);
+
+       if (uf_info->container == UF_CONTAINER_TAILS) {
+               /*
+                * if file is being convered by another process - wait until it
+                * completes
+                */
+               while (1) {
+                       if (reiser4_inode_get_flag(inode,
+                                                  REISER4_PART_IN_CONV)) {
+                               drop_exclusive_access(uf_info);
+                               schedule();
+                               get_exclusive_access(uf_info);
+                               continue;
+                       }
+                       break;
+               }
+               if (uf_info->container == UF_CONTAINER_TAILS) {
+                       result = tail2extent(uf_info);
+                       if (result)
+                               return result;
+               }
+       }
+       if (forever) {
+               /* safe new formatting plugin in stat data */
+               __u64 tograb;
+
+               set_file_notail(inode);
+
+               grab_space_enable();
+               tograb = inode_file_plugin(inode)->estimate.update(inode);
+               result = reiser4_grab_space(tograb, BA_CAN_COMMIT);
+               result = reiser4_update_sd(inode);
+       }
+
+       return result;
+}
+
+/* implentation of vfs' ioctl method of struct file_operations for unix file
+   plugin
+*/
+int
+ioctl_unix_file(struct inode *inode, struct file *filp,
+               unsigned int cmd, unsigned long arg UNUSED_ARG)
+{
+       reiser4_context *ctx;
+       int result;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       switch (cmd) {
+       case REISER4_IOC_UNPACK:
+               get_exclusive_access(unix_file_inode_data(inode));
+               result = unpack(filp, inode, 1 /* forever */ );
+               drop_exclusive_access(unix_file_inode_data(inode));
+               break;
+
+       default:
+               result = RETERR(-ENOSYS);
+               break;
+       }
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* implentation of vfs' bmap method of struct address_space_operations for unix
+   file plugin
+*/
+sector_t bmap_unix_file(struct address_space * mapping, sector_t lblock)
+{
+       reiser4_context *ctx;
+       sector_t result;
+       reiser4_key key;
+       coord_t coord;
+       lock_handle lh;
+       struct inode *inode;
+       item_plugin *iplug;
+       sector_t block;
+
+       inode = mapping->host;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       key_by_inode_and_offset_common(inode,
+                                      (loff_t) lblock * current_blocksize,
+                                      &key);
+
+       init_lh(&lh);
+       result =
+           find_file_item_nohint(&coord, &lh, &key, ZNODE_READ_LOCK, inode);
+       if (cbk_errored(result)) {
+               done_lh(&lh);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       result = zload(coord.node);
+       if (result) {
+               done_lh(&lh);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       iplug = item_plugin_by_coord(&coord);
+       if (iplug->s.file.get_block) {
+               result = iplug->s.file.get_block(&coord, lblock, &block);
+               if (result == 0)
+                       result = block;
+       } else
+               result = RETERR(-EINVAL);
+
+       zrelse(coord.node);
+       done_lh(&lh);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/**
+ * flow_by_inode_unix_file - initizlize structure flow
+ * @inode: inode of file for which read or write is abou
+ * @buf: buffer to perform read to or write from
+ * @user: flag showing whether @buf is user space or kernel space
+ * @size: size of buffer @buf
+ * @off: start offset fro read or write
+ * @op: READ or WRITE
+ * @flow:
+ *
+ * Initializes fields of @flow: key, size of data, i/o mode (read or write).
+ */
+int flow_by_inode_unix_file(struct inode *inode,
+                           const char __user *buf, int user,
+                           loff_t size, loff_t off,
+                           rw_op op, flow_t *flow)
+{
+       assert("nikita-1100", inode != NULL);
+
+       flow->length = size;
+       memcpy(&flow->data, &buf, sizeof(buf));
+       flow->user = user;
+       flow->op = op;
+       assert("nikita-1931", inode_file_plugin(inode) != NULL);
+       assert("nikita-1932",
+              inode_file_plugin(inode)->key_by_inode ==
+              key_by_inode_and_offset_common);
+       /* calculate key of write position and insert it into flow->key */
+       return key_by_inode_and_offset_common(inode, off, &flow->key);
+}
+
+/* plugin->u.file.set_plug_in_sd = NULL
+   plugin->u.file.set_plug_in_inode = NULL
+   plugin->u.file.create_blank_sd = NULL */
+/* plugin->u.file.delete */
+/*
+   plugin->u.file.add_link = reiser4_add_link_common
+   plugin->u.file.rem_link = NULL */
+
+/* plugin->u.file.owns_item
+   this is common_file_owns_item with assertion */
+/* Audited by: green(2002.06.15) */
+int
+owns_item_unix_file(const struct inode *inode /* object to check against */ ,
+                   const coord_t * coord /* coord to check */ )
+{
+       int result;
+
+       result = owns_item_common(inode, coord);
+       if (!result)
+               return 0;
+       if (!plugin_of_group(item_plugin_by_coord(coord),
+                            UNIX_FILE_METADATA_ITEM_TYPE))
+               return 0;
+       assert("vs-547",
+              item_id_by_coord(coord) == EXTENT_POINTER_ID ||
+              item_id_by_coord(coord) == FORMATTING_ID);
+       return 1;
+}
+
+static int setattr_truncate(struct inode *inode, struct iattr *attr)
+{
+       int result;
+       int s_result;
+       loff_t old_size;
+       reiser4_tree *tree;
+
+       inode_check_scale(inode, inode->i_size, attr->ia_size);
+
+       old_size = inode->i_size;
+       tree = reiser4_tree_by_inode(inode);
+
+       result = safe_link_grab(tree, BA_CAN_COMMIT);
+       if (result == 0)
+               result = safe_link_add(inode, SAFE_TRUNCATE);
+       if (result == 0)
+               result = truncate_file_body(inode, attr->ia_size);
+       if (result)
+               warning("vs-1588", "truncate_file failed: oid %lli, "
+                       "old size %lld, new size %lld, retval %d",
+                       (unsigned long long)get_inode_oid(inode),
+                       old_size, attr->ia_size, result);
+
+       s_result = safe_link_grab(tree, BA_CAN_COMMIT);
+       if (s_result == 0)
+               s_result =
+                   safe_link_del(tree, get_inode_oid(inode), SAFE_TRUNCATE);
+       if (s_result != 0) {
+               warning("nikita-3417", "Cannot kill safelink %lli: %i",
+                       (unsigned long long)get_inode_oid(inode), s_result);
+       }
+       safe_link_release(tree);
+       return result;
+}
+
+/* plugin->u.file.setattr method */
+/* This calls inode_setattr and if truncate is in effect it also takes
+   exclusive inode access to avoid races */
+int setattr_unix_file(struct dentry *dentry,   /* Object to change attributes */
+                     struct iattr *attr /* change description */ )
+{
+       int result;
+
+       if (attr->ia_valid & ATTR_SIZE) {
+               reiser4_context *ctx;
+               unix_file_info_t *uf_info;
+
+               /* truncate does reservation itself and requires exclusive
+                  access obtained */
+               ctx = reiser4_init_context(dentry->d_inode->i_sb);
+               if (IS_ERR(ctx))
+                       return PTR_ERR(ctx);
+
+               uf_info = unix_file_inode_data(dentry->d_inode);
+               get_exclusive_access_careful(uf_info, dentry->d_inode);
+               result = setattr_truncate(dentry->d_inode, attr);
+               drop_exclusive_access(uf_info);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+       } else
+               result = reiser4_setattr_common(dentry, attr);
+
+       return result;
+}
+
+/* plugin->u.file.init_inode_data */
+void
+init_inode_data_unix_file(struct inode *inode,
+                         reiser4_object_create_data * crd, int create)
+{
+       unix_file_info_t *data;
+
+       data = unix_file_inode_data(inode);
+       data->container = create ? UF_CONTAINER_EMPTY : UF_CONTAINER_UNKNOWN;
+       init_rwsem(&data->latch);
+       data->tplug = inode_formatting_plugin(inode);
+       data->exclusive_use = 0;
+
+#if REISER4_DEBUG
+       data->ea_owner = NULL;
+       atomic_set(&data->nr_neas, 0);
+#endif
+       init_inode_ordering(inode, crd, create);
+}
+
+/**
+ * delete_object_unix_file - delete_object of file_plugin
+ * @inode: inode to be deleted
+ *
+ * Truncates file to length 0, removes stat data and safe link.
+ */
+int delete_object_unix_file(struct inode *inode)
+{
+       unix_file_info_t *uf_info;
+       int result;
+
+       if (reiser4_inode_get_flag(inode, REISER4_NO_SD))
+               return 0;
+
+       /* truncate file bogy first */
+       uf_info = unix_file_inode_data(inode);
+       get_exclusive_access(uf_info);
+       result = truncate_file_body(inode, 0 /* size */ );
+       drop_exclusive_access(uf_info);
+
+       if (result)
+               warning("", "failed to truncate file (%llu) on removal: %d",
+                       get_inode_oid(inode), result);
+
+       /* remove stat data and safe link */
+       return reiser4_delete_object_common(inode);
+}
+
+/**
+ * sendfile_unix_file - sendfile of struct file_operations
+ * @file: file to be sent
+ * @ppos: position to start from
+ * @count: number of bytes to send
+ * @actor: function to copy data
+ * @target: where to copy read data
+ *
+ * Reads @count bytes from @file and calls @actor for every page read. This is
+ * needed for loop back devices support.
+ */
+ssize_t
+sendfile_unix_file(struct file *file, loff_t *ppos, size_t count,
+                  read_actor_t actor, void *target)
+{
+       reiser4_context *ctx;
+       ssize_t result;
+       struct inode *inode;
+       unix_file_info_t *uf_info;
+
+       inode = file->f_dentry->d_inode;
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       /*
+        * generic_file_sndfile may want to call update_atime. Grab space for
+        * stat data update
+        */
+       result = reiser4_grab_space(estimate_update_common(inode),
+                                   BA_CAN_COMMIT);
+       if (result)
+               goto error;
+       mutex_lock(&inode->i_mutex);
+       reiser4_inode_set_flag(inode, REISER4_HAS_MMAP);
+       mutex_unlock(&inode->i_mutex);
+
+       uf_info = unix_file_inode_data(inode);
+       get_nonexclusive_access(uf_info);
+       result = generic_file_sendfile(file, ppos, count, actor, target);
+       drop_nonexclusive_access(uf_info);
+ error:
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+int
+prepare_write_unix_file(struct file *file, struct page *page,
+                       unsigned from, unsigned to)
+{
+       reiser4_context *ctx;
+       unix_file_info_t *uf_info;
+       int ret;
+
+       ctx = reiser4_init_context(file->f_dentry->d_inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       uf_info = unix_file_inode_data(file->f_dentry->d_inode);
+       get_exclusive_access(uf_info);
+       ret = find_file_state(file->f_dentry->d_inode, uf_info);
+       if (ret == 0) {
+               if (uf_info->container == UF_CONTAINER_TAILS)
+                       ret = -EINVAL;
+               else
+                       ret = do_prepare_write(file, page, from, to);
+       }
+       drop_exclusive_access(uf_info);
+
+       /* don't commit transaction under inode semaphore */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return ret;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/file_conversion.c linux-2.6.20/fs/reiser4/plugin/file/file_conversion.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/file_conversion.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/file_conversion.c       2007-05-06 14:50:43.783001971 +0400
@@ -0,0 +1,594 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser,
+   licensing governed by reiser4/README */
+
+/* This file contains hooks that converts (*) cryptcompress files to unix-files,
+   and a set of protected (**) methods of a cryptcompress file plugin to perform
+   such conversion.
+
+(*)
+   The conversion is performed for incompressible files to reduce cpu and memory
+   usage. If first logical cluster (64K by default) of a file is incompressible,
+   then we make a desicion, that the whole file is incompressible.
+   The conversion can be enabled via installing a special compression mode
+   plugin (CONVX_COMPRESSION_MODE_ID, see plugin/compress/compress_mode.c for
+   details).
+
+(**)
+   The protection means serialization of critical sections (readers and writers
+   of @pset->file)
+*/
+
+#include "../../inode.h"
+#include "../cluster.h"
+#include "file.h"
+
+#define conversion_enabled(inode)                                      \
+        (inode_compression_mode_plugin(inode) ==                      \
+         compression_mode_plugin_by_id(CONVX_COMPRESSION_MODE_ID))
+
+
+/* Located sections (readers and writers of @pset->file) are not
+   permanently critical: cryptcompress file can be converted only
+   if the conversion is enabled (see the macrio above). And we don't
+   convert unix files at all.
+   The following helper macro is a sanity check to decide if we
+   need to protect a located section.
+*/
+#define should_protect(inode)                                          \
+       (inode_file_plugin(inode) ==                                    \
+        file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID) &&             \
+        conversion_enabled(inode))
+
+/* All protected methods have prefix "prot" in their names.
+   It is convenient to construct them by usual (unprotected) ones
+   using the following common macros:
+*/
+
+/* Macro for passive protection.
+   method_cryptcompress contains only readers */
+#define PROT_PASSIVE(type, method, args)                               \
+({                                                                     \
+       type _result;                                                   \
+       struct rw_semaphore * guard =                                   \
+               &reiser4_inode_data(inode)->conv_sem;                   \
+                                                                       \
+       if (should_protect(inode)) {                                    \
+               down_read(guard);                                       \
+               if (!should_protect(inode))                             \
+                       up_read(guard);                                 \
+       }                                                               \
+       if (inode_file_plugin(inode) ==                                 \
+           file_plugin_by_id(UNIX_FILE_PLUGIN_ID))                     \
+               _result = method ## _unix_file args;                    \
+       else                                                            \
+               _result = method ## _cryptcompress args;                \
+       if (should_protect(inode))                                      \
+               up_read(guard);                                         \
+       _result;                                                        \
+})
+
+#define PROT_PASSIVE_VOID(method, args)                                        \
+({                                                                     \
+       struct rw_semaphore * guard =                                   \
+               &reiser4_inode_data(inode)->conv_sem;                   \
+                                                                       \
+       if (should_protect(inode)) {                                    \
+               down_read(guard);                                       \
+               if (!should_protect(inode))                             \
+                       up_read(guard);                                 \
+       }                                                               \
+       if (inode_file_plugin(inode) ==                                 \
+           file_plugin_by_id(UNIX_FILE_PLUGIN_ID))                     \
+               method ## _unix_file args;                              \
+       else                                                            \
+               method ## _cryptcompress args;                          \
+       if (should_protect(inode))                                      \
+               up_read(guard);                                         \
+})
+
+/* Macro for active protection.
+   active_expr contains readers and writers; after its
+   evaluation conversion should be disabled */
+#define PROT_ACTIVE(type, method, args, active_expr)                   \
+({                                                                     \
+       type _result = 0;                                               \
+       struct rw_semaphore * guard =                                   \
+               &reiser4_inode_data(inode)->conv_sem;                   \
+       reiser4_context * ctx = reiser4_init_context(inode->i_sb);      \
+       if (IS_ERR(ctx))                                                \
+               return PTR_ERR(ctx);                                    \
+                                                                       \
+       if (should_protect(inode)) {                                    \
+               down_write(guard);                                      \
+               if (should_protect(inode))                              \
+                       _result = active_expr;                          \
+               up_write(guard);                                        \
+       }                                                               \
+       if (_result == 0) {                                             \
+               if (inode_file_plugin(inode) ==                         \
+                   file_plugin_by_id(UNIX_FILE_PLUGIN_ID))             \
+                       _result =  method ## _unix_file args;           \
+               else                                                    \
+                       _result =  method ## _cryptcompress args;       \
+       }                                                               \
+       reiser4_exit_context(ctx);                                      \
+       _result;                                                        \
+})
+
+/* Pass management to the unix-file plugin with "notail" policy */
+static int __cryptcompress2unixfile(struct file *file, struct inode * inode)
+{
+       int result;
+       reiser4_inode *info;
+       unix_file_info_t * uf;
+       info = reiser4_inode_data(inode);
+
+       result = aset_set_unsafe(&info->pset,
+                           PSET_FILE,
+                           (reiser4_plugin *)
+                           file_plugin_by_id(UNIX_FILE_PLUGIN_ID));
+       if (result)
+               return result;
+       result = aset_set_unsafe(&info->pset,
+                           PSET_FORMATTING,
+                           (reiser4_plugin *)
+                           formatting_plugin_by_id(NEVER_TAILS_FORMATTING_ID));
+       if (result)
+               return result;
+       /* get rid of non-standard plugins */
+       info->plugin_mask &= ~cryptcompress_mask;
+       /* get rid of plugin stat-data extension */
+       info->extmask &= ~(1 << PLUGIN_STAT);
+
+       reiser4_inode_clr_flag(inode, REISER4_SDLEN_KNOWN);
+
+       /* FIXME use init_inode_data_unix_file() instead,
+          but aviod init_inode_ordering() */
+       /* Init unix-file specific part of inode */
+       uf = unix_file_inode_data(inode);
+       uf->container = UF_CONTAINER_UNKNOWN;
+       init_rwsem(&uf->latch);
+       uf->tplug = inode_formatting_plugin(inode);
+       uf->exclusive_use = 0;
+#if REISER4_DEBUG
+       uf->ea_owner = NULL;
+       atomic_set(&uf->nr_neas, 0);
+#endif
+       inode->i_op =
+               &file_plugin_by_id(UNIX_FILE_PLUGIN_ID)->inode_ops;
+       inode->i_fop =
+               &file_plugin_by_id(UNIX_FILE_PLUGIN_ID)->file_ops;
+       inode->i_mapping->a_ops =
+               &file_plugin_by_id(UNIX_FILE_PLUGIN_ID)->as_ops;
+       file->f_op = inode->i_fop;
+       return 0;
+}
+
+#if REISER4_DEBUG
+static int disabled_conversion_inode_ok(struct inode * inode)
+{
+       __u64 extmask = reiser4_inode_data(inode)->extmask;
+       __u16 plugin_mask = reiser4_inode_data(inode)->plugin_mask;
+
+       return ((extmask & (1 << LIGHT_WEIGHT_STAT)) &&
+               (extmask & (1 << UNIX_STAT)) &&
+               (extmask & (1 << LARGE_TIMES_STAT)) &&
+               (extmask & (1 << PLUGIN_STAT)) &&
+               (plugin_mask & (1 << PSET_COMPRESSION_MODE)));
+}
+#endif
+
+/* Assign another mode that will control
+   compression at flush time only */
+static int disable_conversion_no_update_sd(struct inode * inode)
+{
+       int result;
+       result =
+              force_plugin_pset(inode,
+                                PSET_COMPRESSION_MODE,
+                                (reiser4_plugin *)compression_mode_plugin_by_id
+                                (LATTD_COMPRESSION_MODE_ID));
+       assert("edward-1500",
+              ergo(!result, disabled_conversion_inode_ok(inode)));
+       return result;
+}
+
+/* Disable future attempts to check/convert. This function is called by
+   conversion hooks. */
+static int disable_conversion(struct inode * inode)
+{
+       return disable_conversion_no_update_sd(inode);
+}
+
+static int check_position(struct inode * inode,
+                         loff_t pos /* initial position in the file */,
+                         reiser4_cluster_t * clust,
+                         int * check_compress)
+{
+       assert("edward-1505", conversion_enabled(inode));
+       assert("edward-1506", inode->i_size <= inode_cluster_size(inode));
+       /* if file size is more then cluster size, then compressible
+          status must be figured out (i.e. compression was disabled,
+          or file plugin was converted to unix_file) */
+
+       if (pos > inode->i_size)
+               /* first logical cluster will contain a (partial) hole */
+               return disable_conversion(inode);
+       if (inode->i_size == inode_cluster_size(inode))
+               *check_compress = 1;
+       return 0;
+}
+
+static void start_check_compressibility(struct inode * inode,
+                                       reiser4_cluster_t * clust,
+                                       hint_t * hint)
+{
+       assert("edward-1507", clust->index == 1);
+       assert("edward-1508", !tfm_cluster_is_uptodate(&clust->tc));
+       assert("edward-1509", cluster_get_tfm_act(&clust->tc) == TFMA_READ);
+
+       hint_init_zero(hint);
+       clust->hint = hint;
+       clust->index --;
+       clust->nr_pages = count_to_nrpages(fsize_to_count(clust, inode));
+
+       /* first logical cluster (of index #0) must be complete */
+       assert("edward-1510", fsize_to_count(clust, inode) ==
+              inode_cluster_size(inode));
+}
+
+static void finish_check_compressibility(struct inode * inode,
+                                        reiser4_cluster_t * clust,
+                                        hint_t * hint)
+{
+       reiser4_unset_hint(clust->hint);
+       clust->hint = hint;
+       clust->index ++;
+}
+
+#if REISER4_DEBUG
+static int prepped_dclust_ok(hint_t * hint)
+{
+       reiser4_key key;
+       coord_t * coord = &hint->ext_coord.coord;
+
+       item_key_by_coord(coord, &key);
+       return (item_id_by_coord(coord) == CTAIL_ID &&
+               !coord_is_unprepped_ctail(coord) &&
+               (get_key_offset(&key) + nr_units_ctail(coord) ==
+                dclust_get_extension_dsize(hint)));
+}
+#endif
+
+#define fifty_persent(size) (size >> 1)
+/* evaluation of data compressibility */
+#define data_is_compressible(osize, isize)             \
+       (osize < fifty_persent(isize))
+
+/* This is called only once per file life.
+   Read first logical cluster (of index #0) and estimate its compressibility.
+   Save estimation result in @compressible */
+static int read_check_compressibility(struct inode * inode,
+                                     reiser4_cluster_t * clust,
+                                     int * compressible)
+{
+       int i;
+       int result;
+       __u32 dst_len;
+       hint_t tmp_hint;
+       hint_t * cur_hint = clust->hint;
+
+       start_check_compressibility(inode, clust, &tmp_hint);
+
+       result = grab_cluster_pages(inode, clust);
+       if (result)
+               return result;
+       /* Read page cluster here */
+       for (i = 0; i < clust->nr_pages; i++) {
+               struct page *page = clust->pages[i];
+               lock_page(page);
+               result = do_readpage_ctail(inode, clust, page,
+                                          ZNODE_READ_LOCK);
+               unlock_page(page);
+               if (result)
+                       goto error;
+       }
+       tfm_cluster_clr_uptodate(&clust->tc);
+
+       cluster_set_tfm_act(&clust->tc, TFMA_WRITE);
+
+       if (hint_is_valid(&tmp_hint) && !hint_is_unprepped_dclust(&tmp_hint)) {
+               /* lenght of compressed data is known, no need to compress */
+               assert("edward-1511",
+                      znode_is_write_locked(tmp_hint.ext_coord.coord.node));
+               assert("edward-1512",
+                      WITH_DATA(tmp_hint.ext_coord.coord.node,
+                                prepped_dclust_ok(&tmp_hint)));
+               dst_len = dclust_get_extension_dsize(&tmp_hint);
+       }
+       else {
+               tfm_cluster_t * tc = &clust->tc;
+               compression_plugin * cplug = inode_compression_plugin(inode);
+               result = grab_tfm_stream(inode, tc, INPUT_STREAM);
+               if (result)
+                       goto error;
+               for (i = 0; i < clust->nr_pages; i++) {
+                       char *data;
+                       lock_page(clust->pages[i]);
+                       BUG_ON(!PageUptodate(clust->pages[i]));
+                       data = kmap(clust->pages[i]);
+                       memcpy(tfm_stream_data(tc, INPUT_STREAM) + pg_to_off(i),
+                              data, PAGE_CACHE_SIZE);
+                       kunmap(clust->pages[i]);
+                       unlock_page(clust->pages[i]);
+               }
+               result = grab_tfm_stream(inode, tc, OUTPUT_STREAM);
+               if (result)
+                       goto error;
+               result = grab_coa(tc, cplug);
+               if (result)
+                       goto error;
+               tc->len = tc->lsize = fsize_to_count(clust, inode);
+               assert("edward-1513", tc->len == inode_cluster_size(inode));
+               dst_len = tfm_stream_size(tc, OUTPUT_STREAM);
+               cplug->compress(get_coa(tc, cplug->h.id, tc->act),
+                               tfm_input_data(clust), tc->len,
+                               tfm_output_data(clust), &dst_len);
+               assert("edward-1514",
+                      dst_len <= tfm_stream_size(tc, OUTPUT_STREAM));
+       }
+       finish_check_compressibility(inode, clust, cur_hint);
+       *compressible = data_is_compressible(dst_len,
+                                            inode_cluster_size(inode));
+       return 0;
+ error:
+       reiser4_release_cluster_pages(clust);
+       return result;
+}
+
+/* Cut disk cluster of index @idx */
+static int cut_disk_cluster(struct inode * inode, cloff_t idx)
+{
+       reiser4_key from, to;
+       assert("edward-1515", inode_file_plugin(inode) ==
+              file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID));
+       key_by_inode_cryptcompress(inode, clust_to_off(idx, inode), &from);
+       to = from;
+       set_key_offset(&to,
+                      get_key_offset(&from) + inode_cluster_size(inode) - 1);
+       return reiser4_cut_tree(reiser4_tree_by_inode(inode),
+                               &from, &to, inode, 0);
+}
+
+static int reserve_cryptcompress2unixfile(struct inode *inode)
+{
+       reiser4_block_nr unformatted_nodes;
+       reiser4_tree *tree;
+
+       tree = reiser4_tree_by_inode(inode);
+
+       /* number of unformatted nodes which will be created */
+       unformatted_nodes = cluster_nrpages(inode); /* N */
+
+       /*
+        * space required for one iteration of extent->tail conversion:
+        *
+        *     1. kill ctail items
+        *
+        *     2. insert N unformatted nodes
+        *
+        *     3. insert N (worst-case single-block
+        *     extents) extent units.
+        *
+        *     4. drilling to the leaf level by coord_by_key()
+        *
+        *     5. possible update of stat-data
+        *
+        */
+       grab_space_enable();
+       return reiser4_grab_space
+               (2 * tree->height +
+                unformatted_nodes  +
+                unformatted_nodes * estimate_one_insert_into_item(tree) +
+                1 + estimate_one_insert_item(tree) +
+                inode_file_plugin(inode)->estimate.update(inode),
+                BA_CAN_COMMIT);
+}
+
+/* clear flag that indicated conversion and update
+   stat-data with new (unix-file - specific) info */
+static int complete_file_conversion(struct inode *inode)
+{
+       int result;
+
+       grab_space_enable();
+       result =
+           reiser4_grab_space(inode_file_plugin(inode)->estimate.update(inode),
+                              BA_CAN_COMMIT);
+       if (result == 0) {
+               reiser4_inode_clr_flag(inode, REISER4_FILE_CONV_IN_PROGRESS);
+               result = reiser4_update_sd(inode);
+       }
+       if (result)
+               warning("edward-1452",
+                       "Converting %llu to unix-file: update sd failed (%i)",
+                       (unsigned long long)get_inode_oid(inode), result);
+       return 0;
+}
+
+
+/* do conversion */
+static int cryptcompress2unixfile(struct file *file, struct inode * inode,
+                                 reiser4_cluster_t * clust)
+{
+       int i;
+       int result = 0;
+       cryptcompress_info_t *cr_info;
+       unix_file_info_t *uf_info;
+
+       assert("edward-1516", clust->pages[0]->index == 0);
+       assert("edward-1517", clust->hint != NULL);
+
+       /* release all cryptcompress-specific recources */
+       cr_info = cryptcompress_inode_data(inode);
+       result = reserve_cryptcompress2unixfile(inode);
+       if (result)
+               goto out;
+       reiser4_inode_set_flag(inode, REISER4_FILE_CONV_IN_PROGRESS);
+       reiser4_unset_hint(clust->hint);
+       result = cut_disk_cluster(inode, 0);
+       if (result)
+               goto out;
+       /* captured jnode of cluster and assotiated resources (pages,
+          reserved disk space) were released by ->kill_hook() method
+          of the item plugin */
+
+       result = __cryptcompress2unixfile(file, inode);
+       if (result)
+               goto out;
+       /* At this point file is managed by unix file plugin */
+
+       uf_info = unix_file_inode_data(inode);
+
+       assert("edward-1518",
+              ergo(jprivate(clust->pages[0]),
+                   !jnode_is_cluster_page(jprivate(clust->pages[0]))));
+       for(i = 0; i < clust->nr_pages; i++) {
+               assert("edward-1519", clust->pages[i]);
+               assert("edward-1520", PageUptodate(clust->pages[i]));
+
+               result = find_or_create_extent(clust->pages[i]);
+               if (result)
+                       break;
+       }
+       if (!result) {
+               uf_info->container = UF_CONTAINER_EXTENTS;
+               complete_file_conversion(inode);
+       }
+ out:
+       all_grabbed2free();
+       if (result)
+               warning("edward-1453", "Failed to convert file %llu: %i",
+                       (unsigned long long)get_inode_oid(inode), result);
+       return result;
+}
+
+/* Check, then perform or disable conversion if needed */
+int write_conversion_hook(struct file *file, struct inode * inode, loff_t pos,
+                         reiser4_cluster_t * clust, int * progress)
+{
+       int result;
+       int check_compress = 0;
+       int compressible = 0;
+
+       if (!conversion_enabled(inode))
+               return 0;
+       result = check_position(inode, pos, clust, &check_compress);
+       if (result || !check_compress)
+               return result;
+       result = read_check_compressibility(inode, clust, &compressible);
+       if (result)
+               return result;
+
+       /* At this point page cluster is grabbed and uptodate */
+       if (!compressible) {
+               result = cryptcompress2unixfile(file, inode, clust);
+               if (result == 0)
+                       *progress = 1;
+       }
+       else
+               result = disable_conversion(inode);
+
+       reiser4_release_cluster_pages(clust);
+       return result;
+}
+
+static int setattr_conversion_hook(struct inode * inode, struct iattr *attr)
+{
+       return (attr->ia_valid & ATTR_SIZE ? disable_conversion(inode) : 0);
+}
+
+/* Protected methods of cryptcompress file plugin constructed
+   by the macros above */
+
+/* Wrappers with active protection for:
+   . write_cryptcompress;
+   . setattr_cryptcompress;
+*/
+
+ssize_t prot_write_cryptcompress(struct file *file, const char __user *buf,
+                                size_t count, loff_t *off)
+{
+       int prot = 0;
+       int conv = 0;
+       ssize_t written_cr = 0;
+       ssize_t written_uf = 0;
+       struct inode * inode = file->f_dentry->d_inode;
+       struct rw_semaphore * guard = &reiser4_inode_data(inode)->conv_sem;
+
+       if (should_protect(inode)) {
+               prot = 1;
+               down_write(guard);
+       }
+       written_cr = write_cryptcompress(file, buf, count, off, &conv);
+       if (prot)
+               up_write(guard);
+       if (written_cr < 0)
+               return written_cr;
+       if (conv)
+               written_uf = write_unix_file(file, buf + written_cr,
+                                            count - written_cr, off);
+       return written_cr + (written_uf < 0 ? 0 : written_uf);
+}
+
+int prot_setattr_cryptcompress(struct dentry *dentry, struct iattr *attr)
+{
+       struct inode * inode = dentry->d_inode;
+       return PROT_ACTIVE(int, setattr, (dentry, attr),
+                          setattr_conversion_hook(inode, attr));
+}
+
+/* Wrappers with passive protection for:
+   . read_cryptcomperess;
+   . mmap_cryptcompress;
+   . release_cryptcompress;
+   . sendfile_cryptcompress;
+   . delete_object_cryptcompress.
+*/
+ssize_t prot_read_cryptcompress(struct file * file, char __user * buf,
+                               size_t size, loff_t * off)
+{
+       struct inode * inode = file->f_dentry->d_inode;
+       return PROT_PASSIVE(ssize_t, read, (file, buf, size, off));
+}
+
+int prot_mmap_cryptcompress(struct file *file, struct vm_area_struct *vma)
+{
+       struct inode *inode = file->f_dentry->d_inode;
+       return PROT_PASSIVE(int, mmap, (file, vma));
+}
+
+int prot_release_cryptcompress(struct inode *inode, struct file *file)
+{
+       return PROT_PASSIVE(int, release, (inode, file));
+}
+
+ssize_t prot_sendfile_cryptcompress(struct file *file, loff_t *ppos,
+                                   size_t count, read_actor_t actor,
+                                   void *target)
+{
+       struct inode * inode = file->f_dentry->d_inode;
+       return PROT_PASSIVE(ssize_t, sendfile,
+                           (file, ppos, count, actor, target));
+}
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 80
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/file.h linux-2.6.20/fs/reiser4/plugin/file/file.h
--- linux-2.6.20.orig/fs/reiser4/plugin/file/file.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/file.h  2007-05-06 14:50:43.783001971 +0400
@@ -0,0 +1,272 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* this file contains declarations of methods implementing
+   file plugins (UNIX_FILE_PLUGIN_ID, CRYPTCOMPRESS_FILE_PLUGIN_ID
+   and SYMLINK_FILE_PLUGIN_ID) */
+
+#if !defined( __REISER4_FILE_H__ )
+#define __REISER4_FILE_H__
+
+/* declarations of functions implementing UNIX_FILE_PLUGIN_ID file plugin */
+
+/* inode operations */
+int setattr_unix_file(struct dentry *, struct iattr *);
+
+/* file operations */
+ssize_t read_unix_file(struct file *, char __user *buf, size_t read_amount,
+                      loff_t *off);
+ssize_t write_unix_file(struct file *, const char __user *buf, size_t write_amount,
+                       loff_t * off);
+int ioctl_unix_file(struct inode *, struct file *, unsigned int cmd,
+                   unsigned long arg);
+int mmap_unix_file(struct file *, struct vm_area_struct *);
+int open_unix_file(struct inode *, struct file *);
+int release_unix_file(struct inode *, struct file *);
+int sync_unix_file(struct file *, struct dentry *, int datasync);
+ssize_t sendfile_unix_file(struct file *, loff_t *ppos, size_t count,
+                          read_actor_t, void *target);
+
+/* address space operations */
+int readpage_unix_file(struct file *, struct page *);
+int readpages_unix_file(struct file*, struct address_space*, struct list_head*, unsigned);
+int writepages_unix_file(struct address_space *, struct writeback_control *);
+int prepare_write_unix_file(struct file *, struct page *, unsigned from,
+                           unsigned to);
+int commit_write_unix_file(struct file *, struct page *, unsigned from,
+                          unsigned to);
+sector_t bmap_unix_file(struct address_space *, sector_t lblock);
+
+/* file plugin operations */
+int flow_by_inode_unix_file(struct inode *, const char __user *buf,
+                           int user, loff_t, loff_t, rw_op, flow_t *);
+int owns_item_unix_file(const struct inode *, const coord_t *);
+void init_inode_data_unix_file(struct inode *, reiser4_object_create_data *,
+                              int create);
+int delete_object_unix_file(struct inode *);
+
+/*
+ * all the write into unix file is performed by item write method. Write method
+ * of unix file plugin only decides which item plugin (extent or tail) and in
+ * which mode (one from the enum below) to call
+ */
+typedef enum {
+       FIRST_ITEM = 1,
+       APPEND_ITEM = 2,
+       OVERWRITE_ITEM = 3
+} write_mode_t;
+
+/* unix file may be in one the following states */
+typedef enum {
+       UF_CONTAINER_UNKNOWN = 0,
+       UF_CONTAINER_TAILS = 1,
+       UF_CONTAINER_EXTENTS = 2,
+       UF_CONTAINER_EMPTY = 3
+} file_container_t;
+
+struct formatting_plugin;
+struct inode;
+
+/* unix file plugin specific part of reiser4 inode */
+typedef struct unix_file_info {
+       /*
+        * this read-write lock protects file containerization change. Accesses
+        * which do not change file containerization (see file_container_t)
+        * (read, readpage, writepage, write (until tail conversion is
+        * involved)) take read-lock. Accesses which modify file
+        * containerization (truncate, conversion from tail to extent and back)
+        * take write-lock.
+        */
+       struct rw_semaphore latch;
+       /* this enum specifies which items are used to build the file */
+       file_container_t container;
+       /*
+        * plugin which controls when file is to be converted to extents and
+        * back to tail
+        */
+       struct formatting_plugin *tplug;
+       /* if this is set, file is in exclusive use */
+       int exclusive_use;
+#if REISER4_DEBUG
+       /* pointer to task struct of thread owning exclusive access to file */
+       void *ea_owner;
+       atomic_t nr_neas;
+       void *last_reader;
+#endif
+} unix_file_info_t;
+
+struct unix_file_info *unix_file_inode_data(const struct inode *inode);
+void get_exclusive_access(unix_file_info_t *);
+void drop_exclusive_access(unix_file_info_t *);
+void get_nonexclusive_access(unix_file_info_t *);
+void drop_nonexclusive_access(unix_file_info_t *);
+int try_to_get_nonexclusive_access(unix_file_info_t *);
+int find_file_item(hint_t *, const reiser4_key *, znode_lock_mode,
+                  struct inode *);
+int find_file_item_nohint(coord_t *, lock_handle *,
+                         const reiser4_key *, znode_lock_mode,
+                         struct inode *);
+
+int load_file_hint(struct file *, hint_t *);
+void save_file_hint(struct file *, const hint_t *);
+
+#include "../item/extent.h"
+#include "../item/tail.h"
+#include "../item/ctail.h"
+
+struct uf_coord {
+       coord_t coord;
+       lock_handle *lh;
+       int valid;
+       union {
+               extent_coord_extension_t extent;
+               tail_coord_extension_t tail;
+               ctail_coord_extension_t ctail;
+       } extension;
+};
+
+#include "../../forward.h"
+#include "../../seal.h"
+#include "../../lock.h"
+
+/*
+ * This structure is used to speed up file operations (reads and writes).  A
+ * hint is a suggestion about where a key resolved to last time.  A seal
+ * indicates whether a node has been modified since a hint was last recorded.
+ * You check the seal, and if the seal is still valid, you can use the hint
+ * without traversing the tree again.
+ */
+struct hint {
+       seal_t seal; /* a seal over last file item accessed */
+       uf_coord_t ext_coord;
+       loff_t offset;
+       znode_lock_mode mode;
+       lock_handle lh;
+};
+
+static inline int hint_is_valid(hint_t * hint)
+{
+       return hint->ext_coord.valid;
+}
+
+static inline void hint_set_valid(hint_t * hint)
+{
+       hint->ext_coord.valid = 1;
+}
+
+static inline void hint_clr_valid(hint_t * hint)
+{
+       hint->ext_coord.valid = 0;
+}
+
+int load_file_hint(struct file *, hint_t *);
+void save_file_hint(struct file *, const hint_t *);
+void hint_init_zero(hint_t *);
+void reiser4_set_hint(hint_t *, const reiser4_key *, znode_lock_mode);
+int hint_is_set(const hint_t *);
+void reiser4_unset_hint(hint_t *);
+
+int reiser4_update_file_size(struct inode *, reiser4_key *, int update_sd);
+int cut_file_items(struct inode *, loff_t new_size, int update_sd,
+                  loff_t cur_size, int (*update_actor) (struct inode *,
+                                                        reiser4_key *, int));
+#if REISER4_DEBUG
+
+/* return 1 is exclusive access is obtained, 0 - otherwise */
+static inline int ea_obtained(unix_file_info_t * uf_info)
+{
+       int ret;
+
+       ret = down_read_trylock(&uf_info->latch);
+       if (ret)
+               up_read(&uf_info->latch);
+       return !ret;
+}
+
+#endif
+
+/* declarations of functions implementing SYMLINK_FILE_PLUGIN_ID file plugin */
+int reiser4_create_symlink(struct inode *symlink, struct inode *dir,
+                          reiser4_object_create_data *);
+void destroy_inode_symlink(struct inode *);
+
+/* declarations of functions implementing CRYPTCOMPRESS_FILE_PLUGIN_ID
+   file plugin */
+
+/* inode operations */
+int setattr_cryptcompress(struct dentry *, struct iattr *);
+int prot_setattr_cryptcompress(struct dentry *, struct iattr *);
+
+/* file operations */
+ssize_t read_cryptcompress(struct file *, char __user *buf, size_t read_amount,
+                          loff_t * off);
+ssize_t prot_read_cryptcompress(struct file *, char __user *buf,
+                               size_t read_amount, loff_t * off);
+
+ssize_t write_cryptcompress(struct file *, const char __user *buf, size_t write_amount,
+                           loff_t * off, int * conv);
+ssize_t prot_write_cryptcompress(struct file *, const char __user *buf, size_t write_amount,
+                                loff_t * off);
+int mmap_cryptcompress(struct file *, struct vm_area_struct *);
+int prot_mmap_cryptcompress(struct file *, struct vm_area_struct *);
+ssize_t sendfile_cryptcompress(struct file *file, loff_t *ppos, size_t count,
+                              read_actor_t actor, void *target);
+ssize_t prot_sendfile_cryptcompress(struct file *file, loff_t *ppos, size_t count,
+                                   read_actor_t actor, void *target);
+
+int release_cryptcompress(struct inode *, struct file *);
+int prot_release_cryptcompress(struct inode *, struct file *);
+
+/* address space operations */
+extern int readpage_cryptcompress(struct file *, struct page *);
+extern int writepages_cryptcompress(struct address_space *,
+                                    struct writeback_control *);
+/* file plugin operations */
+int flow_by_inode_cryptcompress(struct inode *, const char __user *buf,
+                               int user, loff_t, loff_t, rw_op, flow_t *);
+int key_by_inode_cryptcompress(struct inode *, loff_t off, reiser4_key *);
+int create_cryptcompress(struct inode *, struct inode *,
+                        reiser4_object_create_data *);
+int delete_object_cryptcompress(struct inode *);
+void init_inode_data_cryptcompress(struct inode *, reiser4_object_create_data *,
+                                  int create);
+int cut_tree_worker_cryptcompress(tap_t *, const reiser4_key * from_key,
+                                 const reiser4_key * to_key,
+                                 reiser4_key * smallest_removed,
+                                 struct inode *object, int truncate,
+                                 int *progress);
+void destroy_inode_cryptcompress(struct inode *);
+int open_object_cryptcompress(struct inode * inode, struct file * file);
+
+extern reiser4_plugin_ops cryptcompress_plugin_ops;
+
+#define WRITE_GRANULARITY 32
+
+int tail2extent(unix_file_info_t *);
+int extent2tail(unix_file_info_t *);
+
+int goto_right_neighbor(coord_t *, lock_handle *);
+int find_or_create_extent(struct page *);
+int equal_to_ldk(znode *, const reiser4_key *);
+
+void init_uf_coord(uf_coord_t *uf_coord, lock_handle *lh);
+
+static inline int cbk_errored(int cbk_result)
+{
+       return (cbk_result != CBK_COORD_NOTFOUND
+               && cbk_result != CBK_COORD_FOUND);
+}
+
+/* __REISER4_FILE_H__ */
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/invert.c linux-2.6.20/fs/reiser4/plugin/file/invert.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/invert.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/invert.c        2007-05-06 14:50:43.783001971 +0400
@@ -0,0 +1,493 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Suppose you want to conveniently read and write a large variety of small files conveniently within a single emacs
+   buffer, without having a separate buffer for each 8 byte or so file.  Inverts are the way to do that.  An invert
+   provides you with the contents of a set of subfiles plus its own contents.  It is a file which inherits other files
+   when you read it, and allows you to write to it and through it to the files that it inherits from.  In order for it
+   to know which subfiles each part of your write should go into, there must be delimiters indicating that.  It tries to
+   make that easy for you by providing those delimiters in what you read from it.
+
+  When you read it, an invert performs an inverted assignment.  Instead of taking an assignment command and writing a
+  bunch of files, it takes a bunch of files and composes an assignment command for you to read from it that if executed
+  would create those files.  But which files?  Well, that must be specified in the body of the invert using a special
+  syntax, and that specification is called the invert of the assignment.
+
+  When written to, an invert performs the assignment command that is written
+  to it, and modifies its own body to contain the invert of that
+  assignment.
+
+  In other words, writing to an invert file what you have read from it
+  is the identity operation.
+
+  Malformed assignments cause write errors.  Partial writes are not
+  supported in v4.0, but will be.
+
+  Example:
+
+    If an invert contains:
+
+    /filenameA/<>+"(some text stored in the invert)+/filenameB/<>
+
+======================
+Each element in this definition should be an invert, and all files
+should be called recursively - too.  This is bad. If one of the
+included files in not a regular or invert file, then we can't read
+main file.
+
+I think to make it is possible easier:
+
+internal structure of invert file should be like symlink file. But
+read and write method should be explitely indicated in i/o operation..
+
+By default we read and write (if probably) as symlink and if we
+specify ..invert at reading time that too we can specify it at write time.
+
+example:
+/my_invert_file/..invert<- ( (/filenameA<-"(The contents of filenameA))+"(some text stored in the invert)+(/filenameB<-"(The contents of filenameB) ) )
+will create  /my_invert_file as invert, and will creat /filenameA and /filenameB with specified body.
+
+read of /my_invert_file/..invert will be
+/filenameA<-"(The contents of filenameA)+"(some text stored in the invert)+/filenameB<-"(The contents of filenameB)
+
+but read of /my_invert_file/ will be
+The contents of filenameAsome text stored in the invertThe contents of filenameB
+
+we also can creat this file as
+/my_invert_file/<-/filenameA+"(some text stored in the invert)+/filenameB
+will create  /my_invert_file , and use existing files /filenameA and /filenameB.
+
+and when we will read it will be as previously invert file.
+
+This is correct?
+
+ vv
+DEMIDOV-FIXME-HANS:
+
+Maybe you are right, but then you must disable writes to /my_invert_file/ and only allow writes to /my_invert_file/..invert
+
+Do you agree?  Discuss it on reiserfs-list....
+
+-Hans
+=======================
+
+  Then a read will return:
+
+    /filenameA<-"(The contents of filenameA)+"(some text stored in the invert)+/filenameB<-"(The contents of filenameB)
+
+    and a write of the line above to the invert will set the contents of
+    the invert and filenameA and filenameB to their original values.
+
+  Note that the contents of an invert have no influence on the effect
+  of a write unless the write is a partial write (and a write of a
+  shorter file without using truncate first is a partial write).
+
+  truncate() has no effect on filenameA and filenameB, it merely
+  resets the value of the invert.
+
+  Writes to subfiles via the invert are implemented by preceding them
+  with truncates.
+
+  Parse failures cause write failures.
+
+  Questions to ponder: should the invert be acted on prior to file
+  close when writing to an open filedescriptor?
+
+ Example:
+
+ If an invert contains:
+
+   "(This text and a pair of quotes are all that is here.)
+
+Then a read will return:
+
+   "(This text and a pair of quotes are all that is here.)
+
+*/
+
+/* OPEN method places a struct file in memory associated with invert body
+  and returns something like file descriptor to the user for the future access
+  to the invert file.
+  During opening we parse the body of invert and get a list of the 'entryes'
+  (that describes all its subfiles) and place pointer on the first struct in
+  reiserfs-specific part of invert inode (arbitrary decision).
+
+  Each subfile is described by the struct inv_entry that has a pointer @sd on
+  in-core based stat-data and  a pointer on struct file @f (if we find that the
+  subfile uses more then one unformated node (arbitrary decision), we load
+  struct file in memory, otherwise we load base stat-data (and maybe 1-2 bytes
+  of some other information we need)
+
+  Since READ and WRITE methods for inverts were formulated in assignment
+  language, they don't contain arguments 'size' and 'offset' that make sense
+  only in ordinary read/write methods.
+
+  READ method is a combination of two methods:
+  1) ordinary read method (with offset=0, lenght = @f->...->i_size) for entries
+  with @f != 0, this method uses pointer on struct file as an argument
+  2) read method for inode-less files with @sd != 0, this method uses
+  in-core based stat-data instead struct file as an argument.
+  in the first case we don't use pagecache, just copy data that we got after
+  cbk() into userspace.
+
+  WRITE method for invert files is more complex.
+  Besides declared WRITE-interface in assignment languageb above we need
+  to have an opportunity to edit unwrapped body of invert file with some
+  text editor, it means we need GENERIC WRITE METHOD for invert file:
+
+  my_invert_file/..invert <- "string"
+
+  this method parses "string" and looks for correct subfile signatures, also
+  the parsing process splits this "string" on the set of flows in  accordance
+  with the set of subfiles specified by this signarure.
+  The found list of signatures #S is compared with the opened one #I of invert
+  file. If it doesn't have this one (#I==0, it will be so for instance if we
+  have just create this invert file) the write method assignes found signature
+  (#I=#S;) to the invert file. Then if #I==#S, generic write method splits
+  itself to the some write methods for ordinary or light-weight, or call itself
+  recursively for invert files with corresponding flows.
+  I am not sure, but the list of signatures looks like what mr.Demidov means
+  by 'delimiters'.
+
+  The cases when #S<#I (#I<#S) (in the sense of set-theory) are also available
+  and cause delete (create new) subfiles (arbitrary decision - it may looks
+  too complex, but this interface will be the completest). The order of entries
+  of list #S (#I) and inherited order on #I (#S) must coincide.
+  The other parsing results give malformed signature that aborts READ method
+  and releases all resources.
+
+  Format of subfile (entry) signature:
+
+  "START_MAGIC"<>(TYPE="...",LOOKUP_ARG="...")SUBFILE_BODY"END_MAGIC"
+
+  Legend:
+
+    START_MAGIC - keyword indicates the start of subfile signature;
+
+    <> indicates the start of 'subfile metadata', that is the pair
+  (TYPE="...",LOOKUP_ARG="...") in parenthesis separated by comma.
+
+    TYPE - the string "type" indicates the start of one of the three words:
+  - ORDINARY_FILE,
+  - LIGHT_WEIGHT_FILE,
+  - INVERT_FILE;
+
+    LOOKUP_ARG - lookup argument depends on previous type:
+  */
+
+ /************************************************************/
+ /*       TYPE        *          LOOKUP ARGUMENT             */
+ /************************************************************/
+ /* LIGH_WEIGHT_FILE  *           stat-data key              */
+ /************************************************************/
+ /*   ORDINARY_FILE   *             filename                 */
+ /************************************************************/
+ /*   INVERT_FILE     *             filename                 */
+ /************************************************************/
+
+ /* where:
+  *stat-data key - the string contains stat data key of this subfile, it will be
+  passed to fast-access lookup method for light-weight files;
+  *filename - pathname of this subfile, iyt well be passed to VFS lookup methods
+  for ordinary and invert files;
+
+  SUBFILE_BODY - data of this subfile (it will go to the flow)
+  END_MAGIC - the keyword indicates the end of subfile signature.
+
+  The other simbols inside the signature interpreted as 'unformatted content',
+  which is available with VFS's read_link() (arbitraruy decision).
+
+  NOTE: Parse method for a body of invert file uses mentioned signatures _without_
+  subfile bodies.
+
+  Now the only unclear thing is WRITE in regular light-weight subfile A that we
+  can describe only in  assignment language:
+
+  A <- "some_string"
+
+  I guess we don't want to change stat-data and body items of file A
+  if this file exist, and size(A) != size("some_string") because this operation is
+  expencive, so we only do the partial write if size(A) > size("some_string")
+  and do truncate of the "some_string", and then do A <- "truncated string", if
+  size(A) < size("some_string"). This decision is also arbitrary..
+  */
+
+/* here is infrastructure for formated flows */
+
+#define SUBFILE_HEADER_MAGIC 0x19196605
+#define FLOW_HEADER_MAGIC 0x01194304
+
+#include "../plugin.h"
+#include "../../debug.h"
+#include "../../forward.h"
+#include "../object.h"
+#include "../item/item.h"
+#include "../item/static_stat.h"
+#include "../../dformat.h"
+#include "../znode.h"
+#include "../inode.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>          /* for struct file  */
+#include <linux/list.h>                /* for struct list_head */
+
+typedef enum {
+       LIGHT_WEIGHT_FILE,
+       ORDINARY_FILE,
+       INVERT_FILE
+} inv_entry_type;
+
+typedef struct flow_header {
+       d32 fl_magic;
+       d16 fl_nr;              /* number of subfiles in the flow */
+};
+
+typedef struct subfile_header {
+       d32 sh_magic;           /* subfile magic */
+       d16 sh_type;            /* type of subfile: light-weight, ordinary, invert */
+       d16 sh_arg_len;         /* lenght of lookup argument (filename, key) */
+       d32 sh_body_len;        /* lenght of subfile body */
+};
+
+/* functions to get/set fields of flow header */
+
+static void fl_set_magic(flow_header * fh, __u32 value)
+{
+       cputod32(value, &fh->fh_magic);
+}
+
+static __u32 fl_get_magic(flow_header * fh)
+{
+       return d32tocpu(&fh->fh_magic);
+}
+static void fl_set_number(flow_header * fh, __u16 value)
+{
+       cputod16(value, &fh->fh_nr);
+}
+static unsigned fl_get_number(flow_header * fh)
+{
+       return d16tocpu(&fh->fh_nr);
+}
+
+/* functions to get/set fields of subfile header */
+
+static void sh_set_magic(subfile_header * sh, __u32 value)
+{
+       cputod32(value, &sh->sh_magic);
+}
+
+static __u32 sh_get_magic(subfile_header * sh)
+{
+       return d32tocpu(&sh->sh_magic);
+}
+static void sh_set_type(subfile_header * sh, __u16 value)
+{
+       cputod16(value, &sh->sh_magic);
+}
+static unsigned sh_get_type(subfile_header * sh)
+{
+       return d16tocpu(&sh->sh_magic);
+}
+static void sh_set_arg_len(subfile_header * sh, __u16 value)
+{
+       cputod16(value, &sh->sh_arg_len);
+}
+static unsigned sh_get_arg_len(subfile_header * sh)
+{
+       return d16tocpu(&sh->sh_arg_len);
+}
+static void sh_set_body_len(subfile_header * sh, __u32 value)
+{
+       cputod32(value, &sh->sh_body_len);
+}
+
+static __u32 sh_get_body_len(subfile_header * sh)
+{
+       return d32tocpu(&sh->sh_body_len);
+}
+
+/* in-core minimal stat-data, light-weight analog of inode */
+
+struct incore_sd_base {
+       umode_t isd_mode;
+       nlink_t isd_nlink;
+       loff_t isd_size;
+       char *isd_data;         /* 'subflow' to write */
+};
+
+/* open invert create a list of invert entries,
+   every entry is represented by structure inv_entry */
+
+struct inv_entry {
+       struct list_head *ie_list;
+       struct file *ie_file;   /* this is NULL if the file doesn't
+                                  have unformated nodes */
+       struct incore_sd_base *ie_sd;   /* inode-less analog of struct file */
+};
+
+/* allocate and init invert entry */
+
+static struct inv_entry *allocate_inv_entry(void)
+{
+       struct inv_entry *inv_entry;
+
+       inv_entry = reiser4_kmalloc(sizeof(struct inv_entry), GFP_KERNEL);
+       if (!inv_entry)
+               return ERR_PTR(RETERR(-ENOMEM));
+       inv_entry->ie_file = NULL;
+       inv_entry->ie_sd = NULL;
+       INIT_LIST_HEAD(&inv_entry->ie_list);
+       return inv_entry;
+}
+
+static int put_inv_entry(struct inv_entry *ientry)
+{
+       int result = 0;
+
+       assert("edward-96", ientry != NULL);
+       assert("edward-97", ientry->ie_list != NULL);
+
+       list_del(ientry->ie_list);
+       if (ientry->ie_sd != NULL) {
+               kfree(ientry->ie_sd);
+               kfree(ientry);
+       }
+       if (ientry->ie_file != NULL)
+               result = filp_close(ientry->file, NULL);
+       return result;
+}
+
+static int allocate_incore_sd_base(struct inv_entry *inv_entry)
+{
+       struct incore_sd_base *isd_base assert("edward-98", inv_entry != NULL);
+       assert("edward-99", inv_entry->ie_inode = NULL);
+       assert("edward-100", inv_entry->ie_sd = NULL);
+
+       isd_base = reiser4_kmalloc(sizeof(struct incore_sd_base), GFP_KERNEL);
+       if (!isd_base)
+               return RETERR(-ENOMEM);
+       inv_entry->ie_sd = isd_base;
+       return 0;
+}
+
+/* this can be installed as ->init_inv_entry () method of
+   item_plugins[ STATIC_STAT_DATA_IT ] (fs/reiser4/plugin/item/item.c).
+   Copies data from on-disk stat-data format into light-weight analog of inode .
+   Doesn't hanlde stat-data extensions. */
+
+static void sd_base_load(struct inv_entry *inv_entry, char *sd)
+{
+       reiser4_stat_data_base *sd_base;
+
+       assert("edward-101", inv_entry != NULL);
+       assert("edward-101", inv_entry->ie_sd != NULL);
+       assert("edward-102", sd != NULL);
+
+       sd_base = (reiser4_stat_data_base *) sd;
+       inv_entry->incore_sd_base->isd_mode = d16tocpu(&sd_base->mode);
+       inv_entry->incore_sd_base->isd_nlink = d32tocpu(&sd_base->nlink);
+       inv_entry->incore_sd_base->isd_size = d64tocpu(&sd_base->size);
+       inv_entry->incore_sd_base->isd_data = NULL;
+}
+
+/* initialise incore stat-data */
+
+static void init_incore_sd_base(struct inv_entry *inv_entry, coord_t * coord)
+{
+       reiser4_plugin *plugin = item_plugin_by_coord(coord);
+       void *body = item_body_by_coord(coord);
+
+       assert("edward-103", inv_entry != NULL);
+       assert("edward-104", plugin != NULL);
+       assert("edward-105", body != NULL);
+
+       sd_base_load(inv_entry, body);
+}
+
+/* takes a key or filename and allocates new invert_entry,
+   init and adds it into the list,
+   we use lookup_sd_by_key() for light-weight files and VFS lookup by filename */
+
+int get_inv_entry(struct inode *invert_inode,  /* inode of invert's body */
+                 inv_entry_type type,  /* LIGHT-WEIGHT or ORDINARY */
+                 const reiser4_key * key,      /* key of invert entry stat-data */
+                 char *filename,       /* filename of the file to be opened */
+                 int flags, int mode)
+{
+       int result;
+       struct inv_entry *ientry;
+
+       assert("edward-107", invert_inode != NULL);
+
+       ientry = allocate_inv_entry();
+       if (IS_ERR(ientry))
+               return (PTR_ERR(ientry));
+
+       if (type == LIGHT_WEIGHT_FILE) {
+               coord_t coord;
+               lock_handle lh;
+
+               assert("edward-108", key != NULL);
+
+               init_coord(&coord);
+               init_lh(&lh);
+               result =
+                       lookup_sd_by_key(reiser4_tree_by_inode(invert_inode),
+                                        ZNODE_READ_LOCK, &coord, &lh, key);
+               if (result == 0)
+                       init_incore_sd_base(ientry, coord);
+
+               done_lh(&lh);
+               done_coord(&coord);
+               return (result);
+       } else {
+               struct file *file = filp_open(filename, flags, mode);
+               /* FIXME_EDWARD here we need to check if we
+                  did't follow to any mount point */
+
+               assert("edward-108", filename != NULL);
+
+               if (IS_ERR(file))
+                       return (PTR_ERR(file));
+               ientry->ie_file = file;
+               return 0;
+       }
+}
+
+/* takes inode of invert, reads the body of this invert, parses it,
+   opens all invert entries and return pointer on the first inv_entry */
+
+struct inv_entry *open_invert(struct file *invert_file)
+{
+
+}
+
+ssize_t subfile_read(struct *invert_entry, flow * f)
+{
+
+}
+
+ssize_t subfile_write(struct *invert_entry, flow * f)
+{
+
+}
+
+ssize_t invert_read(struct *file, flow * f)
+{
+
+}
+
+ssize_t invert_write(struct *file, flow * f)
+{
+
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/Makefile linux-2.6.20/fs/reiser4/plugin/file/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/file/Makefile   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/Makefile        2007-05-06 14:50:43.783001971 +0400
@@ -0,0 +1,7 @@
+obj-$(CONFIG_REISER4_FS) += file_plugins.o
+
+file_plugins-objs :=           \
+       file.o                  \
+       tail_conversion.o       \
+       symlink.o               \
+       cryptcompress.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/symfile.c linux-2.6.20/fs/reiser4/plugin/file/symfile.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/symfile.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/symfile.c       2007-05-06 14:50:43.787003221 +0400
@@ -0,0 +1,87 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Symfiles are a generalization of Unix symlinks.
+
+   A symfile when read behaves as though you took its contents and
+   substituted them into the reiser4 naming system as the right hand side
+   of an assignment, and then read that which you had assigned to it.
+
+   A key issue for symfiles is how to implement writes through to
+   subfiles.  In general, one must have some method of determining what
+   of that which is written to the symfile is written to what subfile.
+   This can be done by use of custom plugin methods written by users, or
+   by using a few general methods we provide for those willing to endure
+   the insertion of delimiters into what is read.
+
+   Writing to symfiles without delimiters to denote what is written to
+   what subfile is not supported by any plugins we provide in this
+   release.  Our most sophisticated support for writes is that embodied
+   by the invert plugin (see invert.c).
+
+   A read only version of the /etc/passwd file might be
+   constructed as a symfile whose contents are as follows:
+
+   /etc/passwd/userlines/*
+
+   or
+
+   /etc/passwd/userlines/demidov+/etc/passwd/userlines/edward+/etc/passwd/userlines/reiser+/etc/passwd/userlines/root
+
+   or
+
+   /etc/passwd/userlines/(demidov+edward+reiser+root)
+
+   A symfile with contents
+
+   /filenameA+"(some text stored in the uninvertable symfile)+/filenameB
+
+   will return when read
+
+   The contents of filenameAsome text stored in the uninvertable symfileThe contents of filenameB
+
+   and write of what has been read will not be possible to implement as
+   an identity operation because there are no delimiters denoting the
+   boundaries of what is to be written to what subfile.
+
+   Note that one could make this a read/write symfile if one specified
+   delimiters, and the write method understood those delimiters delimited
+   what was written to subfiles.
+
+   So, specifying the symfile in a manner that allows writes:
+
+   /etc/passwd/userlines/demidov+"(
+   )+/etc/passwd/userlines/edward+"(
+   )+/etc/passwd/userlines/reiser+"(
+   )+/etc/passwd/userlines/root+"(
+   )
+
+   or
+
+   /etc/passwd/userlines/(demidov+"(
+   )+edward+"(
+   )+reiser+"(
+   )+root+"(
+   ))
+
+   and the file demidov might be specified as:
+
+   /etc/passwd/userlines/demidov/username+"(:)+/etc/passwd/userlines/demidov/password+"(:)+/etc/passwd/userlines/demidov/userid+"(:)+/etc/passwd/userlines/demidov/groupid+"(:)+/etc/passwd/userlines/demidov/gecos+"(:)+/etc/passwd/userlines/demidov/home+"(:)+/etc/passwd/userlines/demidov/shell
+
+   or
+
+   /etc/passwd/userlines/demidov/(username+"(:)+password+"(:)+userid+"(:)+groupid+"(:)+gecos+"(:)+home+"(:)+shell)
+
+   Notice that if the file demidov has a carriage return in it, the
+   parsing fails, but then if you put carriage returns in the wrong place
+   in a normal /etc/passwd file it breaks things also.
+
+   Note that it is forbidden to have no text between two interpolations
+   if one wants to be able to define what parts of a write go to what
+   subfiles referenced in an interpolation.
+
+   If one wants to be able to add new lines by writing to the file, one
+   must either write a custom plugin for /etc/passwd that knows how to
+   name an added line, or one must use an invert, or one must use a more
+   sophisticated symfile syntax that we are not planning to write for
+   version 4.0.
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/symlink.c linux-2.6.20/fs/reiser4/plugin/file/symlink.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/symlink.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/symlink.c       2007-05-06 14:50:43.787003221 +0400
@@ -0,0 +1,95 @@
+/* Copyright 2002, 2003, 2005 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../inode.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>
+
+/* file plugin methods specific for symlink files
+   (SYMLINK_FILE_PLUGIN_ID) */
+
+/* this is implementation of create_object method of file plugin for
+   SYMLINK_FILE_PLUGIN_ID
+ */
+
+/**
+ * reiser4_create_symlink - create_object of file plugin for SYMLINK_FILE_PLUGIN_ID
+ * @symlink: inode of symlink object
+ * @dir: inode of parent directory
+ * @info:  parameters of new object
+ *
+ * Inserts stat data with symlink extension where into the tree.
+ */
+int reiser4_create_symlink(struct inode *symlink,
+                          struct inode *dir UNUSED_ARG,
+                          reiser4_object_create_data *data /* info passed to us
+                                                            * this is filled by
+                                                            * reiser4() syscall
+                                                            * in particular */)
+{
+       int result;
+
+       assert("nikita-680", symlink != NULL);
+       assert("nikita-681", S_ISLNK(symlink->i_mode));
+       assert("nikita-685", reiser4_inode_get_flag(symlink, REISER4_NO_SD));
+       assert("nikita-682", dir != NULL);
+       assert("nikita-684", data != NULL);
+       assert("nikita-686", data->id == SYMLINK_FILE_PLUGIN_ID);
+
+       /*
+        * stat data of symlink has symlink extension in which we store
+        * symlink content, that is, path symlink is pointing to.
+        */
+       reiser4_inode_data(symlink)->extmask |= (1 << SYMLINK_STAT);
+
+       assert("vs-838", symlink->i_private == NULL);
+       symlink->i_private = (void *)data->name;
+
+       assert("vs-843", symlink->i_size == 0);
+       INODE_SET_FIELD(symlink, i_size, strlen(data->name));
+
+       /* insert stat data appended with data->name */
+       result = inode_file_plugin(symlink)->write_sd_by_inode(symlink);
+       if (result) {
+               /* FIXME-VS: Make sure that symlink->i_private is not attached
+                  to kmalloced data */
+               INODE_SET_FIELD(symlink, i_size, 0);
+       } else {
+               assert("vs-849", symlink->i_private
+                      && reiser4_inode_get_flag(symlink,
+                                                REISER4_GENERIC_PTR_USED));
+               assert("vs-850",
+                      !memcmp((char *)symlink->i_private, data->name,
+                              (size_t) symlink->i_size + 1));
+       }
+       return result;
+}
+
+/* this is implementation of destroy_inode method of file plugin for
+   SYMLINK_FILE_PLUGIN_ID
+ */
+void destroy_inode_symlink(struct inode *inode)
+{
+       assert("edward-799",
+              inode_file_plugin(inode) ==
+              file_plugin_by_id(SYMLINK_FILE_PLUGIN_ID));
+       assert("edward-800", !is_bad_inode(inode) && is_inode_loaded(inode));
+       assert("edward-801", reiser4_inode_get_flag(inode,
+                                                   REISER4_GENERIC_PTR_USED));
+       assert("vs-839", S_ISLNK(inode->i_mode));
+
+       kfree(inode->i_private);
+       inode->i_private = NULL;
+       reiser4_inode_clr_flag(inode, REISER4_GENERIC_PTR_USED);
+}
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 80
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file/tail_conversion.c linux-2.6.20/fs/reiser4/plugin/file/tail_conversion.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file/tail_conversion.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file/tail_conversion.c       2007-05-06 14:50:43.787003221 +0400
@@ -0,0 +1,729 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../inode.h"
+#include "../../super.h"
+#include "../../page_cache.h"
+#include "../../carry.h"
+#include "../../safe_link.h"
+#include "../../vfs_ops.h"
+
+#include <linux/writeback.h>
+
+/* this file contains:
+   tail2extent and extent2tail */
+
+/* exclusive access to a file is acquired when file state changes: tail2extent, empty2tail, extent2tail, etc */
+void get_exclusive_access(unix_file_info_t * uf_info)
+{
+       assert("nikita-3028", reiser4_schedulable());
+       assert("nikita-3047", LOCK_CNT_NIL(inode_sem_w));
+       assert("nikita-3048", LOCK_CNT_NIL(inode_sem_r));
+       /*
+        * "deadlock avoidance": sometimes we commit a transaction under
+        * rw-semaphore on a file. Such commit can deadlock with another
+        * thread that captured some block (hence preventing atom from being
+        * committed) and waits on rw-semaphore.
+        */
+       reiser4_txn_restart_current();
+       LOCK_CNT_INC(inode_sem_w);
+       down_write(&uf_info->latch);
+       uf_info->exclusive_use = 1;
+       assert("vs-1713", uf_info->ea_owner == NULL);
+       assert("vs-1713", atomic_read(&uf_info->nr_neas) == 0);
+       ON_DEBUG(uf_info->ea_owner = current);
+}
+
+void drop_exclusive_access(unix_file_info_t * uf_info)
+{
+       assert("vs-1714", uf_info->ea_owner == current);
+       assert("vs-1715", atomic_read(&uf_info->nr_neas) == 0);
+       ON_DEBUG(uf_info->ea_owner = NULL);
+       uf_info->exclusive_use = 0;
+       up_write(&uf_info->latch);
+       assert("nikita-3049", LOCK_CNT_NIL(inode_sem_r));
+       assert("nikita-3049", LOCK_CNT_GTZ(inode_sem_w));
+       LOCK_CNT_DEC(inode_sem_w);
+       reiser4_txn_restart_current();
+}
+
+/**
+ * nea_grabbed - do something when file semaphore is down_read-ed
+ * @uf_info:
+ *
+ * This is called when nonexclisive access is obtained on file. All it does is
+ * for debugging purposes.
+ */
+static void nea_grabbed(unix_file_info_t *uf_info)
+{
+#if REISER4_DEBUG
+       LOCK_CNT_INC(inode_sem_r);
+       assert("vs-1716", uf_info->ea_owner == NULL);
+       atomic_inc(&uf_info->nr_neas);
+       uf_info->last_reader = current;
+#endif
+}
+
+/**
+ * get_nonexclusive_access - get nonexclusive access to a file
+ * @uf_info: unix file specific part of inode to obtain access to
+ *
+ * Nonexclusive access is obtained on a file before read, write, readpage.
+ */
+void get_nonexclusive_access(unix_file_info_t *uf_info)
+{
+       assert("nikita-3029", reiser4_schedulable());
+       assert("nikita-3361", get_current_context()->trans->atom == NULL);
+
+       down_read(&uf_info->latch);
+       nea_grabbed(uf_info);
+}
+
+/**
+ * try_to_get_nonexclusive_access - try to get nonexclusive access to a file
+ * @uf_info: unix file specific part of inode to obtain access to
+ *
+ * Non-blocking version of nonexclusive access obtaining.
+ */
+int try_to_get_nonexclusive_access(unix_file_info_t *uf_info)
+{
+       int result;
+
+       result = down_read_trylock(&uf_info->latch);
+       if (result)
+               nea_grabbed(uf_info);
+       return result;
+}
+
+void drop_nonexclusive_access(unix_file_info_t * uf_info)
+{
+       assert("vs-1718", uf_info->ea_owner == NULL);
+       assert("vs-1719", atomic_read(&uf_info->nr_neas) > 0);
+       ON_DEBUG(atomic_dec(&uf_info->nr_neas));
+
+       up_read(&uf_info->latch);
+
+       LOCK_CNT_DEC(inode_sem_r);
+       reiser4_txn_restart_current();
+}
+
+/* part of tail2extent. Cut all items covering @count bytes starting from
+   @offset */
+/* Audited by: green(2002.06.15) */
+static int cut_formatting_items(struct inode *inode, loff_t offset, int count)
+{
+       reiser4_key from, to;
+
+       /* AUDIT: How about putting an assertion here, what would check
+          all provided range is covered by tail items only? */
+       /* key of first byte in the range to be cut  */
+       inode_file_plugin(inode)->key_by_inode(inode, offset, &from);
+
+       /* key of last byte in that range */
+       to = from;
+       set_key_offset(&to, (__u64) (offset + count - 1));
+
+       /* cut everything between those keys */
+       return reiser4_cut_tree(reiser4_tree_by_inode(inode), &from, &to,
+                               inode, 0);
+}
+
+static void release_all_pages(struct page **pages, unsigned nr_pages)
+{
+       unsigned i;
+
+       for (i = 0; i < nr_pages; i++) {
+               if (pages[i] == NULL) {
+                       unsigned j;
+                       for (j = i + 1; j < nr_pages; j++)
+                               assert("vs-1620", pages[j] == NULL);
+                       break;
+               }
+               page_cache_release(pages[i]);
+               pages[i] = NULL;
+       }
+}
+
+/* part of tail2extent. replace tail items with extent one. Content of tail
+   items (@count bytes) being cut are copied already into
+   pages. extent_writepage method is called to create extents corresponding to
+   those pages */
+static int replace(struct inode *inode, struct page **pages, unsigned nr_pages, int count)
+{
+       int result;
+       unsigned i;
+       STORE_COUNTERS;
+
+       if (nr_pages == 0)
+               return 0;
+
+       assert("vs-596", pages[0]);
+
+       /* cut copied items */
+       result = cut_formatting_items(inode, page_offset(pages[0]), count);
+       if (result)
+               return result;
+
+       CHECK_COUNTERS;
+
+       /* put into tree replacement for just removed items: extent item, namely */
+       for (i = 0; i < nr_pages; i++) {
+               result = add_to_page_cache_lru(pages[i], inode->i_mapping,
+                                              pages[i]->index,
+                                              mapping_gfp_mask(inode->
+                                                               i_mapping));
+               if (result)
+                       break;
+               unlock_page(pages[i]);
+               result = find_or_create_extent(pages[i]);
+               if (result)
+                       break;
+               SetPageUptodate(pages[i]);
+       }
+       return result;
+}
+
+#define TAIL2EXTENT_PAGE_NUM 3 /* number of pages to fill before cutting tail
+                                * items */
+
+static int reserve_tail2extent_iteration(struct inode *inode)
+{
+       reiser4_block_nr unformatted_nodes;
+       reiser4_tree *tree;
+
+       tree = reiser4_tree_by_inode(inode);
+
+       /* number of unformatted nodes which will be created */
+       unformatted_nodes = TAIL2EXTENT_PAGE_NUM;
+
+       /*
+        * space required for one iteration of extent->tail conversion:
+        *
+        *     1. kill N tail items
+        *
+        *     2. insert TAIL2EXTENT_PAGE_NUM unformatted nodes
+        *
+        *     3. insert TAIL2EXTENT_PAGE_NUM (worst-case single-block
+        *     extents) extent units.
+        *
+        *     4. drilling to the leaf level by coord_by_key()
+        *
+        *     5. possible update of stat-data
+        *
+        */
+       grab_space_enable();
+       return reiser4_grab_space
+           (2 * tree->height +
+            TAIL2EXTENT_PAGE_NUM +
+            TAIL2EXTENT_PAGE_NUM * estimate_one_insert_into_item(tree) +
+            1 + estimate_one_insert_item(tree) +
+            inode_file_plugin(inode)->estimate.update(inode), BA_CAN_COMMIT);
+}
+
+/* clear stat data's flag indicating that conversion is being converted */
+static int complete_conversion(struct inode *inode)
+{
+       int result;
+
+       grab_space_enable();
+       result =
+           reiser4_grab_space(inode_file_plugin(inode)->estimate.update(inode),
+                              BA_CAN_COMMIT);
+       if (result == 0) {
+               reiser4_inode_clr_flag(inode, REISER4_PART_MIXED);
+               result = reiser4_update_sd(inode);
+       }
+       if (result)
+               warning("vs-1696", "Failed to clear converting bit of %llu: %i",
+                       (unsigned long long)get_inode_oid(inode), result);
+       return 0;
+}
+
+/**
+ * find_start
+ * @inode:
+ * @id:
+ * @offset:
+ *
+ * this is used by tail2extent and extent2tail to detect where previous
+ * uncompleted conversion stopped
+ */
+static int find_start(struct inode *inode, reiser4_plugin_id id, __u64 *offset)
+{
+       int result;
+       lock_handle lh;
+       coord_t coord;
+       unix_file_info_t *ufo;
+       int found;
+       reiser4_key key;
+
+       ufo = unix_file_inode_data(inode);
+       init_lh(&lh);
+       result = 0;
+       found = 0;
+       inode_file_plugin(inode)->key_by_inode(inode, *offset, &key);
+       do {
+               init_lh(&lh);
+               result = find_file_item_nohint(&coord, &lh, &key,
+                                              ZNODE_READ_LOCK, inode);
+
+               if (result == CBK_COORD_FOUND) {
+                       if (coord.between == AT_UNIT) {
+                               /*coord_clear_iplug(&coord); */
+                               result = zload(coord.node);
+                               if (result == 0) {
+                                       if (item_id_by_coord(&coord) == id)
+                                               found = 1;
+                                       else
+                                               item_plugin_by_coord(&coord)->s.
+                                                   file.append_key(&coord,
+                                                                   &key);
+                                       zrelse(coord.node);
+                               }
+                       } else
+                               result = RETERR(-ENOENT);
+               }
+               done_lh(&lh);
+       } while (result == 0 && !found);
+       *offset = get_key_offset(&key);
+       return result;
+}
+
+/**
+ * tail2extent
+ * @uf_info:
+ *
+ *
+ */
+int tail2extent(unix_file_info_t *uf_info)
+{
+       int result;
+       reiser4_key key;        /* key of next byte to be moved to page */
+       char *p_data;           /* data of page */
+       unsigned page_off = 0,  /* offset within the page where to copy data */
+           count;              /* number of bytes of item which can be
+                                * copied to page */
+       struct page *pages[TAIL2EXTENT_PAGE_NUM];
+       struct page *page;
+       int done;               /* set to 1 when all file is read */
+       char *item;
+       int i;
+       struct inode *inode;
+       int first_iteration;
+       int bytes;
+       __u64 offset;
+
+       assert("nikita-3362", ea_obtained(uf_info));
+       inode = unix_file_info_to_inode(uf_info);
+       assert("nikita-3412", !IS_RDONLY(inode));
+       assert("vs-1649", uf_info->container != UF_CONTAINER_EXTENTS);
+       assert("", !reiser4_inode_get_flag(inode, REISER4_PART_IN_CONV));
+
+       offset = 0;
+       first_iteration = 1;
+       result = 0;
+       if (reiser4_inode_get_flag(inode, REISER4_PART_MIXED)) {
+               /*
+                * file is marked on disk as there was a conversion which did
+                * not complete due to either crash or some error. Find which
+                * offset tail conversion stopped at
+                */
+               result = find_start(inode, FORMATTING_ID, &offset);
+               if (result == -ENOENT) {
+                       /* no tail items found, everything is converted */
+                       uf_info->container = UF_CONTAINER_EXTENTS;
+                       complete_conversion(inode);
+                       return 0;
+               } else if (result != 0)
+                       /* some other error */
+                       return result;
+               first_iteration = 0;
+       }
+
+       reiser4_inode_set_flag(inode, REISER4_PART_IN_CONV);
+
+       /* get key of first byte of a file */
+       inode_file_plugin(inode)->key_by_inode(inode, offset, &key);
+
+       done = 0;
+       while (done == 0) {
+               memset(pages, 0, sizeof(pages));
+               result = reserve_tail2extent_iteration(inode);
+               if (result != 0)
+                       goto out;
+               if (first_iteration) {
+                       reiser4_inode_set_flag(inode, REISER4_PART_MIXED);
+                       reiser4_update_sd(inode);
+                       first_iteration = 0;
+               }
+               bytes = 0;
+               for (i = 0; i < sizeof_array(pages) && done == 0; i++) {
+                       assert("vs-598",
+                              (get_key_offset(&key) & ~PAGE_CACHE_MASK) == 0);
+                       page = alloc_page(reiser4_ctx_gfp_mask_get());
+                       if (!page) {
+                               result = RETERR(-ENOMEM);
+                               goto error;
+                       }
+
+                       page->index =
+                           (unsigned long)(get_key_offset(&key) >>
+                                           PAGE_CACHE_SHIFT);
+                       /*
+                        * usually when one is going to longterm lock znode (as
+                        * find_file_item does, for instance) he must not hold
+                        * locked pages. However, there is an exception for
+                        * case tail2extent. Pages appearing here are not
+                        * reachable to everyone else, they are clean, they do
+                        * not have jnodes attached so keeping them locked do
+                        * not risk deadlock appearance
+                        */
+                       assert("vs-983", !PagePrivate(page));
+                       reiser4_invalidate_pages(inode->i_mapping, page->index,
+                                                1, 0);
+
+                       for (page_off = 0; page_off < PAGE_CACHE_SIZE;) {
+                               coord_t coord;
+                               lock_handle lh;
+
+                               /* get next item */
+                               /* FIXME: we might want to readahead here */
+                               init_lh(&lh);
+                               result =
+                                   find_file_item_nohint(&coord, &lh, &key,
+                                                         ZNODE_READ_LOCK,
+                                                         inode);
+                               if (result != CBK_COORD_FOUND) {
+                                       /*
+                                        * error happened of not items of file
+                                        * were found
+                                        */
+                                       done_lh(&lh);
+                                       page_cache_release(page);
+                                       goto error;
+                               }
+
+                               if (coord.between == AFTER_UNIT) {
+                                       /*
+                                        * end of file is reached. Padd page
+                                        * with zeros
+                                        */
+                                       done_lh(&lh);
+                                       done = 1;
+                                       p_data = kmap_atomic(page, KM_USER0);
+                                       memset(p_data + page_off, 0,
+                                              PAGE_CACHE_SIZE - page_off);
+                                       kunmap_atomic(p_data, KM_USER0);
+                                       break;
+                               }
+
+                               result = zload(coord.node);
+                               if (result) {
+                                       page_cache_release(page);
+                                       done_lh(&lh);
+                                       goto error;
+                               }
+                               assert("vs-856", coord.between == AT_UNIT);
+                               item = ((char *)item_body_by_coord(&coord)) +
+                                       coord.unit_pos;
+
+                               /* how many bytes to copy */
+                               count =
+                                   item_length_by_coord(&coord) -
+                                   coord.unit_pos;
+                               /* limit length of copy to end of page */
+                               if (count > PAGE_CACHE_SIZE - page_off)
+                                       count = PAGE_CACHE_SIZE - page_off;
+
+                               /*
+                                * copy item (as much as will fit starting from
+                                * the beginning of the item) into the page
+                                */
+                               p_data = kmap_atomic(page, KM_USER0);
+                               memcpy(p_data + page_off, item, count);
+                               kunmap_atomic(p_data, KM_USER0);
+
+                               page_off += count;
+                               bytes += count;
+                               set_key_offset(&key,
+                                              get_key_offset(&key) + count);
+
+                               zrelse(coord.node);
+                               done_lh(&lh);
+                       } /* end of loop which fills one page by content of
+                          * formatting items */
+
+                       if (page_off) {
+                               /* something was copied into page */
+                               pages[i] = page;
+                       } else {
+                               page_cache_release(page);
+                               assert("vs-1648", done == 1);
+                               break;
+                       }
+               } /* end of loop through pages of one conversion iteration */
+
+               if (i > 0) {
+                       result = replace(inode, pages, i, bytes);
+                       release_all_pages(pages, sizeof_array(pages));
+                       if (result)
+                               goto error;
+                       /*
+                        * We have to drop exclusive access to avoid deadlock
+                        * which may happen because called by reiser4_writepages
+                        * capture_unix_file requires to get non-exclusive
+                        * access to a file. It is safe to drop EA in the middle
+                        * of tail2extent conversion because write_unix_file,
+                        * setattr_unix_file(truncate), mmap_unix_file,
+                        * release_unix_file(extent2tail) checks if conversion
+                        * is not in progress (see comments before
+                        * get_exclusive_access_careful().
+                        * Other processes that acquire non-exclusive access
+                        * (read_unix_file, reiser4_writepages, etc) should work
+                        * on partially converted files.
+                        */
+                       drop_exclusive_access(uf_info);
+                       /* throttle the conversion */
+                       reiser4_throttle_write(inode);
+                       get_exclusive_access(uf_info);
+
+                       /*
+                        * nobody is allowed to complete conversion but a
+                        * process which started it
+                        */
+                       assert("", reiser4_inode_get_flag(inode,
+                                                         REISER4_PART_MIXED));
+               }
+       }
+
+       reiser4_inode_clr_flag(inode, REISER4_PART_IN_CONV);
+
+       if (result == 0) {
+               /* file is converted to extent items */
+               assert("vs-1697", reiser4_inode_get_flag(inode,
+                                                        REISER4_PART_MIXED));
+
+               uf_info->container = UF_CONTAINER_EXTENTS;
+               complete_conversion(inode);
+       } else {
+               /*
+                * conversion is not complete. Inode was already marked as
+                * REISER4_PART_CONV and stat-data were updated at the first
+                * iteration of the loop above.
+                */
+             error:
+               release_all_pages(pages, sizeof_array(pages));
+               warning("nikita-2282", "Partial conversion of %llu: %i",
+                       (unsigned long long)get_inode_oid(inode), result);
+       }
+
+      out:
+       return result;
+}
+
+static int reserve_extent2tail_iteration(struct inode *inode)
+{
+       reiser4_tree *tree;
+
+       tree = reiser4_tree_by_inode(inode);
+       /*
+        * reserve blocks for (in this order):
+        *
+        *     1. removal of extent item
+        *
+        *     2. insertion of tail by insert_flow()
+        *
+        *     3. drilling to the leaf level by coord_by_key()
+        *
+        *     4. possible update of stat-data
+        */
+       grab_space_enable();
+       return reiser4_grab_space
+           (estimate_one_item_removal(tree) +
+            estimate_insert_flow(tree->height) +
+            1 + estimate_one_insert_item(tree) +
+            inode_file_plugin(inode)->estimate.update(inode), BA_CAN_COMMIT);
+}
+
+/* for every page of file: read page, cut part of extent pointing to this page,
+   put data of page tree by tail item */
+int extent2tail(unix_file_info_t *uf_info)
+{
+       int result;
+       struct inode *inode;
+       struct page *page;
+       unsigned long num_pages, i;
+       unsigned long start_page;
+       reiser4_key from;
+       reiser4_key to;
+       unsigned count;
+       __u64 offset;
+
+       assert("nikita-3362", ea_obtained(uf_info));
+       inode = unix_file_info_to_inode(uf_info);
+       assert("nikita-3412", !IS_RDONLY(inode));
+       assert("vs-1649", uf_info->container != UF_CONTAINER_TAILS);
+       assert("", !reiser4_inode_get_flag(inode, REISER4_PART_IN_CONV));
+
+       offset = 0;
+       if (reiser4_inode_get_flag(inode, REISER4_PART_MIXED)) {
+               /*
+                * file is marked on disk as there was a conversion which did
+                * not complete due to either crash or some error. Find which
+                * offset tail conversion stopped at
+                */
+               result = find_start(inode, EXTENT_POINTER_ID, &offset);
+               if (result == -ENOENT) {
+                       /* no extent found, everything is converted */
+                       uf_info->container = UF_CONTAINER_TAILS;
+                       complete_conversion(inode);
+                       return 0;
+               } else if (result != 0)
+                       /* some other error */
+                       return result;
+       }
+
+       reiser4_inode_set_flag(inode, REISER4_PART_IN_CONV);
+
+       /* number of pages in the file */
+       num_pages =
+           (inode->i_size + - offset + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+       start_page = offset >> PAGE_CACHE_SHIFT;
+
+       inode_file_plugin(inode)->key_by_inode(inode, offset, &from);
+       to = from;
+
+       result = 0;
+       for (i = 0; i < num_pages; i++) {
+               __u64 start_byte;
+
+               result = reserve_extent2tail_iteration(inode);
+               if (result != 0)
+                       break;
+               if (i == 0 && offset == 0) {
+                       reiser4_inode_set_flag(inode, REISER4_PART_MIXED);
+                       reiser4_update_sd(inode);
+               }
+
+               page = read_mapping_page(inode->i_mapping,
+                                        (unsigned)(i + start_page), NULL);
+               if (IS_ERR(page)) {
+                       result = PTR_ERR(page);
+                       break;
+               }
+
+               wait_on_page_locked(page);
+
+               if (!PageUptodate(page)) {
+                       page_cache_release(page);
+                       result = RETERR(-EIO);
+                       break;
+               }
+
+               /* cut part of file we have read */
+               start_byte = (__u64) (i << PAGE_CACHE_SHIFT);
+               set_key_offset(&from, start_byte);
+               set_key_offset(&to, start_byte + PAGE_CACHE_SIZE - 1);
+               /*
+                * reiser4_cut_tree_object() returns -E_REPEAT to allow atom
+                * commits during over-long truncates. But
+                * extent->tail conversion should be performed in one
+                * transaction.
+                */
+               result = reiser4_cut_tree(reiser4_tree_by_inode(inode), &from,
+                                         &to, inode, 0);
+
+               if (result) {
+                       page_cache_release(page);
+                       break;
+               }
+
+               /* put page data into tree via tail_write */
+               count = PAGE_CACHE_SIZE;
+               if ((i == (num_pages - 1)) &&
+                   (inode->i_size & ~PAGE_CACHE_MASK))
+                       /* last page can be incompleted */
+                       count = (inode->i_size & ~PAGE_CACHE_MASK);
+               while (count) {
+                       struct dentry dentry;
+                       struct file file;
+                       loff_t pos;
+
+                       dentry.d_inode = inode;
+                       file.f_dentry = &dentry;
+                       file.private_data = NULL;
+                       file.f_pos = start_byte;
+                       file.private_data = NULL;
+                       pos = start_byte;
+                       result = reiser4_write_tail(&file,
+                                                   (char __user *)kmap(page),
+                                                   count, &pos);
+                       reiser4_free_file_fsdata(&file);
+                       if (result <= 0) {
+                               warning("", "reiser4_write_tail failed");
+                               page_cache_release(page);
+                               reiser4_inode_clr_flag(inode, REISER4_PART_IN_CONV);
+                               return result;
+                       }
+                       count -= result;
+               }
+
+               /* release page */
+               lock_page(page);
+               /* page is already detached from jnode and mapping. */
+               assert("vs-1086", page->mapping == NULL);
+               assert("nikita-2690",
+                      (!PagePrivate(page) && jprivate(page) == 0));
+               /* waiting for writeback completion with page lock held is
+                * perfectly valid. */
+               wait_on_page_writeback(page);
+               reiser4_drop_page(page);
+               /* release reference taken by read_cache_page() above */
+               page_cache_release(page);
+
+               drop_exclusive_access(uf_info);
+               /* throttle the conversion */
+               reiser4_throttle_write(inode);
+               get_exclusive_access(uf_info);
+               /*
+                * nobody is allowed to complete conversion but a process which
+                * started it
+                */
+               assert("", reiser4_inode_get_flag(inode, REISER4_PART_MIXED));
+       }
+
+       reiser4_inode_clr_flag(inode, REISER4_PART_IN_CONV);
+
+       if (i == num_pages) {
+               /* file is converted to formatted items */
+               assert("vs-1698", reiser4_inode_get_flag(inode,
+                                                        REISER4_PART_MIXED));
+               assert("vs-1260",
+                      inode_has_no_jnodes(reiser4_inode_data(inode)));
+
+               uf_info->container = UF_CONTAINER_TAILS;
+               complete_conversion(inode);
+               return 0;
+       }
+       /*
+        * conversion is not complete. Inode was already marked as
+        * REISER4_PART_MIXED and stat-data were updated at the first *
+        * iteration of the loop above.
+        */
+       warning("nikita-2282",
+               "Partial conversion of %llu: %lu of %lu: %i",
+               (unsigned long long)get_inode_oid(inode), i,
+               num_pages, result);
+
+       return result;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file_ops.c linux-2.6.20/fs/reiser4/plugin/file_ops.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file_ops.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file_ops.c   2007-05-06 14:50:43.787003221 +0400
@@ -0,0 +1,168 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+   reiser4/README */
+
+/* this file contains typical implementations for some of methods of
+   struct file_operations and of struct address_space_operations
+*/
+
+#include "../inode.h"
+#include "object.h"
+
+/* file operations */
+
+/* implementation of vfs's llseek method of struct file_operations for
+   typical directory can be found in readdir_common.c
+*/
+loff_t reiser4_llseek_dir_common(struct file *, loff_t, int origin);
+
+/* implementation of vfs's readdir method of struct file_operations for
+   typical directory can be found in readdir_common.c
+*/
+int reiser4_readdir_common(struct file *, void *dirent, filldir_t);
+
+/**
+ * reiser4_release_dir_common - release of struct file_operations
+ * @inode: inode of released file
+ * @file: file to release
+ *
+ * Implementation of release method of struct file_operations for typical
+ * directory. All it does is freeing of reiser4 specific file data.
+*/
+int reiser4_release_dir_common(struct inode *inode, struct file *file)
+{
+       reiser4_context *ctx;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       reiser4_free_file_fsdata(file);
+       reiser4_exit_context(ctx);
+       return 0;
+}
+
+/* this is common implementation of vfs's fsync method of struct
+   file_operations
+*/
+int reiser4_sync_common(struct file *file, struct dentry *dentry, int datasync)
+{
+       reiser4_context *ctx;
+       int result;
+
+       ctx = reiser4_init_context(dentry->d_inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       result = txnmgr_force_commit_all(dentry->d_inode->i_sb, 0);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* this is common implementation of vfs's sendfile method of struct
+   file_operations
+
+   Reads @count bytes from @file and calls @actor for every page read. This is
+   needed for loop back devices support.
+*/
+#if 0
+ssize_t
+sendfile_common(struct file *file, loff_t *ppos, size_t count,
+               read_actor_t actor, void *target)
+{
+       reiser4_context *ctx;
+       ssize_t result;
+
+       ctx = reiser4_init_context(file->f_dentry->d_inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       result = generic_file_sendfile(file, ppos, count, actor, target);
+       reiser4_exit_context(ctx);
+       return result;
+}
+#endif  /*  0  */
+
+/* address space operations */
+
+/* this is common implementation of vfs's prepare_write method of struct
+   address_space_operations
+*/
+int
+prepare_write_common(struct file *file, struct page *page, unsigned from,
+                    unsigned to)
+{
+       reiser4_context *ctx;
+       int result;
+
+       ctx = reiser4_init_context(page->mapping->host->i_sb);
+       result = do_prepare_write(file, page, from, to);
+
+       /* don't commit transaction under inode semaphore */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+
+       return result;
+}
+
+/* this is helper for prepare_write_common and prepare_write_unix_file
+ */
+int
+do_prepare_write(struct file *file, struct page *page, unsigned from,
+                unsigned to)
+{
+       int result;
+       file_plugin *fplug;
+       struct inode *inode;
+
+       assert("umka-3099", file != NULL);
+       assert("umka-3100", page != NULL);
+       assert("umka-3095", PageLocked(page));
+
+       if (to - from == PAGE_CACHE_SIZE || PageUptodate(page))
+               return 0;
+
+       inode = page->mapping->host;
+       fplug = inode_file_plugin(inode);
+
+       if (page->mapping->a_ops->readpage == NULL)
+               return RETERR(-EINVAL);
+
+       result = page->mapping->a_ops->readpage(file, page);
+       if (result != 0) {
+               SetPageError(page);
+               ClearPageUptodate(page);
+               /* All reiser4 readpage() implementations should return the
+                * page locked in case of error. */
+               assert("nikita-3472", PageLocked(page));
+       } else {
+               /*
+                * ->readpage() either:
+                *
+                *     1. starts IO against @page. @page is locked for IO in
+                *     this case.
+                *
+                *     2. doesn't start IO. @page is unlocked.
+                *
+                * In either case, page should be locked.
+                */
+               lock_page(page);
+               /*
+                * IO (if any) is completed at this point. Check for IO
+                * errors.
+                */
+               if (!PageUptodate(page))
+                       result = RETERR(-EIO);
+       }
+       assert("umka-3098", PageLocked(page));
+       return result;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file_ops_readdir.c linux-2.6.20/fs/reiser4/plugin/file_ops_readdir.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file_ops_readdir.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file_ops_readdir.c   2007-05-06 14:50:43.791004471 +0400
@@ -0,0 +1,657 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "../inode.h"
+
+/* return true, iff @coord points to the valid directory item that is part of
+ * @inode directory. */
+static int is_valid_dir_coord(struct inode *inode, coord_t * coord)
+{
+       return plugin_of_group(item_plugin_by_coord(coord),
+                              DIR_ENTRY_ITEM_TYPE) &&
+              inode_file_plugin(inode)->owns_item(inode, coord);
+}
+
+/* compare two logical positions within the same directory */
+static cmp_t dir_pos_cmp(const dir_pos * p1, const dir_pos * p2)
+{
+       cmp_t result;
+
+       assert("nikita-2534", p1 != NULL);
+       assert("nikita-2535", p2 != NULL);
+
+       result = de_id_cmp(&p1->dir_entry_key, &p2->dir_entry_key);
+       if (result == EQUAL_TO) {
+               int diff;
+
+               diff = p1->pos - p2->pos;
+               result =
+                   (diff < 0) ? LESS_THAN : (diff ? GREATER_THAN : EQUAL_TO);
+       }
+       return result;
+}
+
+/* see comment before reiser4_readdir_common() for overview of why "adjustment" is
+ * necessary. */
+static void
+adjust_dir_pos(struct file *dir,
+              readdir_pos * readdir_spot, const dir_pos * mod_point, int adj)
+{
+       dir_pos *pos;
+
+       /*
+        * new directory entry was added (adj == +1) or removed (adj == -1) at
+        * the @mod_point. Directory file descriptor @dir is doing readdir and
+        * is currently positioned at @readdir_spot. Latter has to be updated
+        * to maintain stable readdir.
+        */
+       /* directory is positioned to the beginning. */
+       if (readdir_spot->entry_no == 0)
+               return;
+
+       pos = &readdir_spot->position;
+       switch (dir_pos_cmp(mod_point, pos)) {
+       case LESS_THAN:
+               /* @mod_pos is _before_ @readdir_spot, that is, entry was
+                * added/removed on the left (in key order) of current
+                * position. */
+               /* logical number of directory entry readdir is "looking" at
+                * changes */
+               readdir_spot->entry_no += adj;
+               assert("nikita-2577",
+                      ergo(dir != NULL, reiser4_get_dir_fpos(dir) + adj >= 0));
+               if (de_id_cmp(&pos->dir_entry_key,
+                             &mod_point->dir_entry_key) == EQUAL_TO) {
+                       assert("nikita-2575", mod_point->pos < pos->pos);
+                       /*
+                        * if entry added/removed has the same key as current
+                        * for readdir, update counter of duplicate keys in
+                        * @readdir_spot.
+                        */
+                       pos->pos += adj;
+               }
+               break;
+       case GREATER_THAN:
+               /* directory is modified after @pos: nothing to do. */
+               break;
+       case EQUAL_TO:
+               /* cannot insert an entry readdir is looking at, because it
+                  already exists. */
+               assert("nikita-2576", adj < 0);
+               /* directory entry to which @pos points to is being
+                  removed.
+
+                  NOTE-NIKITA: Right thing to do is to update @pos to point
+                  to the next entry. This is complex (we are under spin-lock
+                  for one thing). Just rewind it to the beginning. Next
+                  readdir will have to scan the beginning of
+                  directory. Proper solution is to use semaphore in
+                  spin lock's stead and use rewind_right() here.
+
+                  NOTE-NIKITA: now, semaphore is used, so...
+                */
+               memset(readdir_spot, 0, sizeof *readdir_spot);
+       }
+}
+
+/* scan all file-descriptors for this directory and adjust their
+   positions respectively. Should be used by implementations of
+   add_entry and rem_entry of dir plugin */
+void reiser4_adjust_dir_file(struct inode *dir, const struct dentry *de,
+                            int offset, int adj)
+{
+       reiser4_file_fsdata *scan;
+       dir_pos mod_point;
+
+       assert("nikita-2536", dir != NULL);
+       assert("nikita-2538", de != NULL);
+       assert("nikita-2539", adj != 0);
+
+       build_de_id(dir, &de->d_name, &mod_point.dir_entry_key);
+       mod_point.pos = offset;
+
+       spin_lock_inode(dir);
+
+       /*
+        * new entry was added/removed in directory @dir. Scan all file
+        * descriptors for @dir that are currently involved into @readdir and
+        * update them.
+        */
+
+       list_for_each_entry(scan, get_readdir_list(dir), dir.linkage)
+               adjust_dir_pos(scan->back, &scan->dir.readdir, &mod_point, adj);
+
+       spin_unlock_inode(dir);
+}
+
+/*
+ * traverse tree to start/continue readdir from the readdir position @pos.
+ */
+static int dir_go_to(struct file *dir, readdir_pos * pos, tap_t * tap)
+{
+       reiser4_key key;
+       int result;
+       struct inode *inode;
+
+       assert("nikita-2554", pos != NULL);
+
+       inode = dir->f_dentry->d_inode;
+       result = inode_dir_plugin(inode)->build_readdir_key(dir, &key);
+       if (result != 0)
+               return result;
+       result = reiser4_object_lookup(inode,
+                                      &key,
+                                      tap->coord,
+                                      tap->lh,
+                                      tap->mode,
+                                      FIND_EXACT,
+                                      LEAF_LEVEL, LEAF_LEVEL,
+                                      0, &tap->ra_info);
+       if (result == CBK_COORD_FOUND)
+               result = rewind_right(tap, (int)pos->position.pos);
+       else {
+               tap->coord->node = NULL;
+               done_lh(tap->lh);
+               result = RETERR(-EIO);
+       }
+       return result;
+}
+
+/*
+ * handling of non-unique keys: calculate at what ordinal position within
+ * sequence of directory items with identical keys @pos is.
+ */
+static int set_pos(struct inode *inode, readdir_pos * pos, tap_t * tap)
+{
+       int result;
+       coord_t coord;
+       lock_handle lh;
+       tap_t scan;
+       de_id *did;
+       reiser4_key de_key;
+
+       coord_init_zero(&coord);
+       init_lh(&lh);
+       reiser4_tap_init(&scan, &coord, &lh, ZNODE_READ_LOCK);
+       reiser4_tap_copy(&scan, tap);
+       reiser4_tap_load(&scan);
+       pos->position.pos = 0;
+
+       did = &pos->position.dir_entry_key;
+
+       if (is_valid_dir_coord(inode, scan.coord)) {
+
+               build_de_id_by_key(unit_key_by_coord(scan.coord, &de_key), did);
+
+               while (1) {
+
+                       result = go_prev_unit(&scan);
+                       if (result != 0)
+                               break;
+
+                       if (!is_valid_dir_coord(inode, scan.coord)) {
+                               result = -EINVAL;
+                               break;
+                       }
+
+                       /* get key of directory entry */
+                       unit_key_by_coord(scan.coord, &de_key);
+                       if (de_id_key_cmp(did, &de_key) != EQUAL_TO) {
+                               /* duplicate-sequence is over */
+                               break;
+                       }
+                       pos->position.pos++;
+               }
+       } else
+               result = RETERR(-ENOENT);
+       reiser4_tap_relse(&scan);
+       reiser4_tap_done(&scan);
+       return result;
+}
+
+/*
+ * "rewind" directory to @offset, i.e., set @pos and @tap correspondingly.
+ */
+static int dir_rewind(struct file *dir, readdir_pos * pos, tap_t * tap)
+{
+       __u64 destination;
+       __s64 shift;
+       int result;
+       struct inode *inode;
+       loff_t dirpos;
+
+       assert("nikita-2553", dir != NULL);
+       assert("nikita-2548", pos != NULL);
+       assert("nikita-2551", tap->coord != NULL);
+       assert("nikita-2552", tap->lh != NULL);
+
+       dirpos = reiser4_get_dir_fpos(dir);
+       shift = dirpos - pos->fpos;
+       /* this is logical directory entry within @dir which we are rewinding
+        * to */
+       destination = pos->entry_no + shift;
+
+       inode = dir->f_dentry->d_inode;
+       if (dirpos < 0)
+               return RETERR(-EINVAL);
+       else if (destination == 0ll || dirpos == 0) {
+               /* rewind to the beginning of directory */
+               memset(pos, 0, sizeof *pos);
+               return dir_go_to(dir, pos, tap);
+       } else if (destination >= inode->i_size)
+               return RETERR(-ENOENT);
+
+       if (shift < 0) {
+               /* I am afraid of negative numbers */
+               shift = -shift;
+               /* rewinding to the left */
+               if (shift <= (int)pos->position.pos) {
+                       /* destination is within sequence of entries with
+                          duplicate keys. */
+                       result = dir_go_to(dir, pos, tap);
+               } else {
+                       shift -= pos->position.pos;
+                       while (1) {
+                               /* repetitions: deadlock is possible when
+                                  going to the left. */
+                               result = dir_go_to(dir, pos, tap);
+                               if (result == 0) {
+                                       result = rewind_left(tap, shift);
+                                       if (result == -E_DEADLOCK) {
+                                               reiser4_tap_done(tap);
+                                               continue;
+                                       }
+                               }
+                               break;
+                       }
+               }
+       } else {
+               /* rewinding to the right */
+               result = dir_go_to(dir, pos, tap);
+               if (result == 0)
+                       result = rewind_right(tap, shift);
+       }
+       if (result == 0) {
+               result = set_pos(inode, pos, tap);
+               if (result == 0) {
+                       /* update pos->position.pos */
+                       pos->entry_no = destination;
+                       pos->fpos = dirpos;
+               }
+       }
+       return result;
+}
+
+/*
+ * Function that is called by common_readdir() on each directory entry while
+ * doing readdir. ->filldir callback may block, so we had to release long term
+ * lock while calling it. To avoid repeating tree traversal, seal is used. If
+ * seal is broken, we return -E_REPEAT. Node is unlocked in this case.
+ *
+ * Whether node is unlocked in case of any other error is undefined. It is
+ * guaranteed to be still locked if success (0) is returned.
+ *
+ * When ->filldir() wants no more, feed_entry() returns 1, and node is
+ * unlocked.
+ */
+static int
+feed_entry(struct file *f,
+          readdir_pos * pos, tap_t * tap, filldir_t filldir, void *dirent)
+{
+       item_plugin *iplug;
+       char *name;
+       reiser4_key sd_key;
+       int result;
+       char buf[DE_NAME_BUF_LEN];
+       char name_buf[32];
+       char *local_name;
+       unsigned file_type;
+       seal_t seal;
+       coord_t *coord;
+       reiser4_key entry_key;
+
+       coord = tap->coord;
+       iplug = item_plugin_by_coord(coord);
+
+       /* pointer to name within the node */
+       name = iplug->s.dir.extract_name(coord, buf);
+       assert("nikita-1371", name != NULL);
+
+       /* key of object the entry points to */
+       if (iplug->s.dir.extract_key(coord, &sd_key) != 0)
+               return RETERR(-EIO);
+
+       /* we must release longterm znode lock before calling filldir to avoid
+          deadlock which may happen if filldir causes page fault. So, copy
+          name to intermediate buffer */
+       if (strlen(name) + 1 > sizeof(name_buf)) {
+               local_name = kmalloc(strlen(name) + 1,
+                                    reiser4_ctx_gfp_mask_get());
+               if (local_name == NULL)
+                       return RETERR(-ENOMEM);
+       } else
+               local_name = name_buf;
+
+       strcpy(local_name, name);
+       file_type = iplug->s.dir.extract_file_type(coord);
+
+       unit_key_by_coord(coord, &entry_key);
+       reiser4_seal_init(&seal, coord, &entry_key);
+
+       longterm_unlock_znode(tap->lh);
+
+       /*
+        * send information about directory entry to the ->filldir() filler
+        * supplied to us by caller (VFS).
+        *
+        * ->filldir is entitled to do weird things. For example, ->filldir
+        * supplied by knfsd re-enters file system. Make sure no locks are
+        * held.
+        */
+       assert("nikita-3436", lock_stack_isclean(get_current_lock_stack()));
+
+       reiser4_txn_restart_current();
+       result = filldir(dirent, name, (int)strlen(name),
+                        /* offset of this entry */
+                        f->f_pos,
+                        /* inode number of object bounden by this entry */
+                        oid_to_uino(get_key_objectid(&sd_key)), file_type);
+       if (local_name != name_buf)
+               kfree(local_name);
+       if (result < 0)
+               /* ->filldir() is satisfied. (no space in buffer, IOW) */
+               result = 1;
+       else
+               result = reiser4_seal_validate(&seal, coord, &entry_key,
+                                              tap->lh, tap->mode,
+                                              ZNODE_LOCK_HIPRI);
+       return result;
+}
+
+static void move_entry(readdir_pos * pos, coord_t * coord)
+{
+       reiser4_key de_key;
+       de_id *did;
+
+       /* update @pos */
+       ++pos->entry_no;
+       did = &pos->position.dir_entry_key;
+
+       /* get key of directory entry */
+       unit_key_by_coord(coord, &de_key);
+
+       if (de_id_key_cmp(did, &de_key) == EQUAL_TO)
+               /* we are within sequence of directory entries
+                  with duplicate keys. */
+               ++pos->position.pos;
+       else {
+               pos->position.pos = 0;
+               build_de_id_by_key(&de_key, did);
+       }
+       ++pos->fpos;
+}
+
+/*
+ *     STATELESS READDIR
+ *
+ * readdir support in reiser4 relies on ability to update readdir_pos embedded
+ * into reiser4_file_fsdata on each directory modification (name insertion and
+ * removal), see reiser4_readdir_common() function below. This obviously doesn't
+ * work when reiser4 is accessed over NFS, because NFS doesn't keep any state
+ * across client READDIR requests for the same directory.
+ *
+ * To address this we maintain a "pool" of detached reiser4_file_fsdata
+ * (d_cursor). Whenever NFS readdir request comes, we detect this, and try to
+ * find detached reiser4_file_fsdata corresponding to previous readdir
+ * request. In other words, additional state is maintained on the
+ * server. (This is somewhat contrary to the design goals of NFS protocol.)
+ *
+ * To efficiently detect when our ->readdir() method is called by NFS server,
+ * dentry is marked as "stateless" in reiser4_decode_fh() (this is checked by
+ * file_is_stateless() function).
+ *
+ * To find out d_cursor in the pool, we encode client id (cid) in the highest
+ * bits of NFS readdir cookie: when first readdir request comes to the given
+ * directory from the given client, cookie is set to 0. This situation is
+ * detected, global cid_counter is incremented, and stored in highest bits of
+ * all direntry offsets returned to the client, including last one. As the
+ * only valid readdir cookie is one obtained as direntry->offset, we are
+ * guaranteed that next readdir request (continuing current one) will have
+ * current cid in the highest bits of starting readdir cookie. All d_cursors
+ * are hashed into per-super-block hash table by (oid, cid) key.
+ *
+ * In addition d_cursors are placed into per-super-block radix tree where they
+ * are keyed by oid alone. This is necessary to efficiently remove them during
+ * rmdir.
+ *
+ * At last, currently unused d_cursors are linked into special list. This list
+ * is used d_cursor_shrink to reclaim d_cursors on memory pressure.
+ *
+ */
+
+/*
+ * prepare for readdir.
+ */
+static int dir_readdir_init(struct file *f, tap_t * tap, readdir_pos ** pos)
+{
+       struct inode *inode;
+       reiser4_file_fsdata *fsdata;
+       int result;
+
+       assert("nikita-1359", f != NULL);
+       inode = f->f_dentry->d_inode;
+       assert("nikita-1360", inode != NULL);
+
+       if (!S_ISDIR(inode->i_mode))
+               return RETERR(-ENOTDIR);
+
+       /* try to find detached readdir state */
+       result = reiser4_attach_fsdata(f, inode);
+       if (result != 0)
+               return result;
+
+       fsdata = reiser4_get_file_fsdata(f);
+       assert("nikita-2571", fsdata != NULL);
+       if (IS_ERR(fsdata))
+               return PTR_ERR(fsdata);
+
+       /* add file descriptor to the readdir list hanging of directory
+        * inode. This list is used to scan "readdirs-in-progress" while
+        * inserting or removing names in the directory. */
+       spin_lock_inode(inode);
+       if (list_empty_careful(&fsdata->dir.linkage))
+               list_add(&fsdata->dir.linkage, get_readdir_list(inode));
+       *pos = &fsdata->dir.readdir;
+       spin_unlock_inode(inode);
+
+       /* move @tap to the current position */
+       return dir_rewind(f, *pos, tap);
+}
+
+/* this is implementation of vfs's llseek method of struct file_operations for
+   typical directory
+   See comment before reiser4_readdir_common() for explanation.
+*/
+loff_t reiser4_llseek_dir_common(struct file * file, loff_t off, int origin)
+{
+       reiser4_context *ctx;
+       loff_t result;
+       struct inode *inode;
+
+       inode = file->f_dentry->d_inode;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       mutex_lock(&inode->i_mutex);
+
+       /* update ->f_pos */
+       result = default_llseek(file, off, origin);
+       if (result >= 0) {
+               int ff;
+               coord_t coord;
+               lock_handle lh;
+               tap_t tap;
+               readdir_pos *pos;
+
+               coord_init_zero(&coord);
+               init_lh(&lh);
+               reiser4_tap_init(&tap, &coord, &lh, ZNODE_READ_LOCK);
+
+               ff = dir_readdir_init(file, &tap, &pos);
+               reiser4_detach_fsdata(file);
+               if (ff != 0)
+                       result = (loff_t) ff;
+               reiser4_tap_done(&tap);
+       }
+       reiser4_detach_fsdata(file);
+       mutex_unlock(&inode->i_mutex);
+
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* this is common implementation of vfs's readdir method of struct
+   file_operations
+
+   readdir problems:
+
+   readdir(2)/getdents(2) interface is based on implicit assumption that
+   readdir can be restarted from any particular point by supplying file system
+   with off_t-full of data. That is, file system fills ->d_off field in struct
+   dirent and later user passes ->d_off to the seekdir(3), which is, actually,
+   implemented by glibc as lseek(2) on directory.
+
+   Reiser4 cannot restart readdir from 64 bits of data, because two last
+   components of the key of directory entry are unknown, which given 128 bits:
+   locality and type fields in the key of directory entry are always known, to
+   start readdir() from given point objectid and offset fields have to be
+   filled.
+
+   Traditional UNIX API for scanning through directory
+   (readdir/seekdir/telldir/opendir/closedir/rewindir/getdents) is based on the
+   assumption that directory is structured very much like regular file, in
+   particular, it is implied that each name within given directory (directory
+   entry) can be uniquely identified by scalar offset and that such offset is
+   stable across the life-time of the name is identifies.
+
+   This is manifestly not so for reiser4. In reiser4 the only stable unique
+   identifies for the directory entry is its key that doesn't fit into
+   seekdir/telldir API.
+
+   solution:
+
+   Within each file descriptor participating in readdir-ing of directory
+   plugin/dir/dir.h:readdir_pos is maintained. This structure keeps track of
+   the "current" directory entry that file descriptor looks at. It contains a
+   key of directory entry (plus some additional info to deal with non-unique
+   keys that we wouldn't dwell onto here) and a logical position of this
+   directory entry starting from the beginning of the directory, that is
+   ordinal number of this entry in the readdir order.
+
+   Obviously this logical position is not stable in the face of directory
+   modifications. To work around this, on each addition or removal of directory
+   entry all file descriptors for directory inode are scanned and their
+   readdir_pos are updated accordingly (adjust_dir_pos()).
+*/
+int reiser4_readdir_common(struct file *f /* directory file being read */,
+                          void *dirent /* opaque data passed to us by VFS */,
+                          filldir_t filld /* filler function passed to us
+                                           * by VFS */)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *inode;
+       coord_t coord;
+       lock_handle lh;
+       tap_t tap;
+       readdir_pos *pos;
+
+       assert("nikita-1359", f != NULL);
+       inode = f->f_dentry->d_inode;
+       assert("nikita-1360", inode != NULL);
+
+       if (!S_ISDIR(inode->i_mode))
+               return RETERR(-ENOTDIR);
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       coord_init_zero(&coord);
+       init_lh(&lh);
+       reiser4_tap_init(&tap, &coord, &lh, ZNODE_READ_LOCK);
+
+       reiser4_readdir_readahead_init(inode, &tap);
+
+      repeat:
+       result = dir_readdir_init(f, &tap, &pos);
+       if (result == 0) {
+               result = reiser4_tap_load(&tap);
+               /* scan entries one by one feeding them to @filld */
+               while (result == 0) {
+                       coord_t *coord;
+
+                       coord = tap.coord;
+                       assert("nikita-2572", coord_is_existing_unit(coord));
+                       assert("nikita-3227", is_valid_dir_coord(inode, coord));
+
+                       result = feed_entry(f, pos, &tap, filld, dirent);
+                       if (result > 0) {
+                               break;
+                       } else if (result == 0) {
+                               ++f->f_pos;
+                               result = go_next_unit(&tap);
+                               if (result == -E_NO_NEIGHBOR ||
+                                   result == -ENOENT) {
+                                       result = 0;
+                                       break;
+                               } else if (result == 0) {
+                                       if (is_valid_dir_coord(inode, coord))
+                                               move_entry(pos, coord);
+                                       else
+                                               break;
+                               }
+                       } else if (result == -E_REPEAT) {
+                               /* feed_entry() had to restart. */
+                               ++f->f_pos;
+                               reiser4_tap_relse(&tap);
+                               goto repeat;
+                       } else
+                               warning("vs-1617",
+                                       "reiser4_readdir_common: unexpected error %d",
+                                       result);
+               }
+               reiser4_tap_relse(&tap);
+
+               if (result >= 0)
+                       f->f_version = inode->i_version;
+       } else if (result == -E_NO_NEIGHBOR || result == -ENOENT)
+               result = 0;
+       reiser4_tap_done(&tap);
+       reiser4_detach_fsdata(f);
+
+       /* try to update directory's atime */
+       if (reiser4_grab_space_force(inode_file_plugin(inode)->estimate.update(inode),
+                              BA_CAN_COMMIT) != 0)
+               warning("", "failed to update atime on readdir: %llu",
+                       get_inode_oid(inode));
+       else
+               file_accessed(f);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+
+       return (result <= 0) ? result : 0;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/file_plugin_common.c linux-2.6.20/fs/reiser4/plugin/file_plugin_common.c
--- linux-2.6.20.orig/fs/reiser4/plugin/file_plugin_common.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/file_plugin_common.c 2007-05-06 14:50:43.791004471 +0400
@@ -0,0 +1,1007 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+   reiser4/README */
+
+/* this file contains typical implementations for most of methods of
+   file plugin
+*/
+
+#include "../inode.h"
+#include "object.h"
+#include "../safe_link.h"
+
+#include <linux/quotaops.h>
+
+static int insert_new_sd(struct inode *inode);
+static int update_sd(struct inode *inode);
+
+/* this is common implementation of write_sd_by_inode method of file plugin
+   either insert stat data or update it
+ */
+int write_sd_by_inode_common(struct inode *inode /* object to save */ )
+{
+       int result;
+
+       assert("nikita-730", inode != NULL);
+
+       if (reiser4_inode_get_flag(inode, REISER4_NO_SD))
+               /* object doesn't have stat-data yet */
+               result = insert_new_sd(inode);
+       else
+               result = update_sd(inode);
+       if (result != 0 && result != -ENAMETOOLONG && result != -ENOMEM)
+               /* Don't issue warnings about "name is too long" */
+               warning("nikita-2221", "Failed to save sd for %llu: %i",
+                       (unsigned long long)get_inode_oid(inode), result);
+       return result;
+}
+
+/* this is common implementation of key_by_inode method of file plugin
+ */
+int
+key_by_inode_and_offset_common(struct inode *inode, loff_t off,
+                              reiser4_key * key)
+{
+       reiser4_key_init(key);
+       set_key_locality(key, reiser4_inode_data(inode)->locality_id);
+       set_key_ordering(key, get_inode_ordering(inode));
+       set_key_objectid(key, get_inode_oid(inode));    /*FIXME: inode->i_ino */
+       set_key_type(key, KEY_BODY_MINOR);
+       set_key_offset(key, (__u64) off);
+       return 0;
+}
+
+/* this is common implementation of set_plug_in_inode method of file plugin
+ */
+int set_plug_in_inode_common(struct inode *object /* inode to set plugin on */ ,
+                            struct inode *parent /* parent object */ ,
+                            reiser4_object_create_data * data  /* creational
+                                                                * data */ )
+{
+       __u64 mask;
+
+       object->i_mode = data->mode;
+       /* this should be plugin decision */
+       object->i_uid = current->fsuid;
+       object->i_mtime = object->i_atime = object->i_ctime = CURRENT_TIME;
+
+       /* support for BSD style group-id assignment. See mount's manual page
+          description of bsdgroups ext2 mount options for more details */
+       if (reiser4_is_set(object->i_sb, REISER4_BSD_GID))
+               object->i_gid = parent->i_gid;
+       else if (parent->i_mode & S_ISGID) {
+               /* parent directory has sguid bit */
+               object->i_gid = parent->i_gid;
+               if (S_ISDIR(object->i_mode))
+                       /* sguid is inherited by sub-directories */
+                       object->i_mode |= S_ISGID;
+       } else
+               object->i_gid = current->fsgid;
+
+       /* this object doesn't have stat-data yet */
+       reiser4_inode_set_flag(object, REISER4_NO_SD);
+#if 0
+       /* this is now called after all inode plugins are initialized:
+          do_create_vfs_child after adjust_to_parent */
+       /* setup inode and file-operations for this inode */
+       setup_inode_ops(object, data);
+#endif
+       object->i_nlink = 0;
+       reiser4_seal_init(&reiser4_inode_data(object)->sd_seal, NULL, NULL);
+       mask = (1 << UNIX_STAT) | (1 << LIGHT_WEIGHT_STAT);
+       if (!reiser4_is_set(object->i_sb, REISER4_32_BIT_TIMES))
+               mask |= (1 << LARGE_TIMES_STAT);
+
+       reiser4_inode_data(object)->extmask = mask;
+       return 0;
+}
+
+/* this is common implementation of adjust_to_parent method of file plugin for
+   regular files
+ */
+int adjust_to_parent_common(struct inode *object /* new object */ ,
+                           struct inode *parent /* parent directory */ ,
+                           struct inode *root /* root directory */ )
+{
+       assert("nikita-2165", object != NULL);
+       if (parent == NULL)
+               parent = root;
+       assert("nikita-2069", parent != NULL);
+
+       /*
+        * inherit missing plugins from parent
+        */
+
+       grab_plugin_pset(object, parent, PSET_FILE);
+       grab_plugin_pset(object, parent, PSET_SD);
+       grab_plugin_pset(object, parent, PSET_FORMATTING);
+       grab_plugin_pset(object, parent, PSET_PERM);
+       return 0;
+}
+
+/* this is common implementation of adjust_to_parent method of file plugin for
+   typical directories
+ */
+int adjust_to_parent_common_dir(struct inode *object /* new object */ ,
+                               struct inode *parent /* parent directory */ ,
+                               struct inode *root /* root directory */ )
+{
+       int result = 0;
+       pset_member memb;
+
+       assert("nikita-2166", object != NULL);
+       if (parent == NULL)
+               parent = root;
+       assert("nikita-2167", parent != NULL);
+
+       /*
+        * inherit missing plugins from parent
+        */
+       for (memb = 0; memb < PSET_LAST; ++memb) {
+               result = grab_plugin_pset(object, parent, memb);
+               if (result != 0)
+                       break;
+       }
+       return result;
+}
+
+int adjust_to_parent_cryptcompress(struct inode *object /* new object */ ,
+                                  struct inode *parent /* parent directory */,
+                                  struct inode *root /* root directory */)
+{
+       int result;
+       result = adjust_to_parent_common(object, parent, root);
+       if (result)
+               return result;
+       assert("edward-1416", parent != NULL);
+
+       grab_plugin_pset(object, parent, PSET_CLUSTER);
+       grab_plugin_pset(object, parent, PSET_CIPHER);
+       grab_plugin_pset(object, parent, PSET_DIGEST);
+       grab_plugin_pset(object, parent, PSET_COMPRESSION);
+       grab_plugin_pset(object, parent, PSET_COMPRESSION_MODE);
+
+       return 0;
+}
+
+/* this is common implementation of create_object method of file plugin
+ */
+int reiser4_create_object_common(struct inode *object, struct inode *parent,
+                                reiser4_object_create_data * data)
+{
+       reiser4_block_nr reserve;
+       assert("nikita-744", object != NULL);
+       assert("nikita-745", parent != NULL);
+       assert("nikita-747", data != NULL);
+       assert("nikita-748", reiser4_inode_get_flag(object, REISER4_NO_SD));
+
+       reserve = estimate_create_common(object);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT))
+               return RETERR(-ENOSPC);
+       return write_sd_by_inode_common(object);
+}
+
+static int common_object_delete_no_reserve(struct inode *inode);
+
+/**
+ * reiser4_delete_object_common - delete_object of file_plugin
+ * @inode: inode to be deleted
+ *
+ * This is common implementation of delete_object method of file_plugin. It
+ * applies to object its deletion consists of removing two items - stat data
+ * and safe-link.
+ */
+int reiser4_delete_object_common(struct inode *inode)
+{
+       int result;
+
+       assert("nikita-1477", inode != NULL);
+       /* FIXME: if file body deletion failed (i/o error, for instance),
+          inode->i_size can be != 0 here */
+       assert("nikita-3420", inode->i_size == 0 || S_ISLNK(inode->i_mode));
+       assert("nikita-3421", inode->i_nlink == 0);
+
+       if (!reiser4_inode_get_flag(inode, REISER4_NO_SD)) {
+               reiser4_block_nr reserve;
+
+               /* grab space which is needed to remove 2 items from the tree:
+                  stat data and safe-link */
+               reserve = 2 *
+                 estimate_one_item_removal(reiser4_tree_by_inode(inode));
+               if (reiser4_grab_space_force(reserve,
+                                            BA_RESERVED | BA_CAN_COMMIT))
+                       return RETERR(-ENOSPC);
+               result = common_object_delete_no_reserve(inode);
+       } else
+               result = 0;
+       return result;
+}
+
+/**
+ * reiser4_delete_dir_common - delete_object of file_plugin
+ * @inode: inode to be deleted
+ *
+ * This is common implementation of delete_object method of file_plugin for
+ * typical directory. It calls done method of dir_plugin to remove "." and
+ * removes stat data and safe-link.
+ */
+int reiser4_delete_dir_common(struct inode *inode)
+{
+       int result;
+       dir_plugin *dplug;
+
+       assert("", (get_current_context() &&
+                   get_current_context()->trans->atom == NULL));
+
+       dplug = inode_dir_plugin(inode);
+       assert("vs-1101", dplug && dplug->done);
+
+       /* kill cursors which might be attached to inode */
+       reiser4_kill_cursors(inode);
+
+       /* grab space enough for removing two items */
+       if (reiser4_grab_space
+           (2 * estimate_one_item_removal(reiser4_tree_by_inode(inode)),
+            BA_RESERVED | BA_CAN_COMMIT))
+               return RETERR(-ENOSPC);
+
+       result = dplug->done(inode);
+       if (!result)
+               result = common_object_delete_no_reserve(inode);
+       return result;
+}
+
+/* this is common implementation of add_link method of file plugin
+ */
+int reiser4_add_link_common(struct inode *object, struct inode *parent)
+{
+       /*
+        * increment ->i_nlink and update ->i_ctime
+        */
+
+       INODE_INC_FIELD(object, i_nlink);
+       object->i_ctime = CURRENT_TIME;
+       return 0;
+}
+
+/* this is common implementation of rem_link method of file plugin
+ */
+int reiser4_rem_link_common(struct inode *object, struct inode *parent)
+{
+       assert("nikita-2021", object != NULL);
+       assert("nikita-2163", object->i_nlink > 0);
+
+       /*
+        * decrement ->i_nlink and update ->i_ctime
+        */
+
+       INODE_DEC_FIELD(object, i_nlink);
+       object->i_ctime = CURRENT_TIME;
+       return 0;
+}
+
+/* this is common implementation of rem_link method of file plugin for typical
+   directory
+*/
+int rem_link_common_dir(struct inode *object, struct inode *parent UNUSED_ARG)
+{
+       assert("nikita-20211", object != NULL);
+       assert("nikita-21631", object->i_nlink > 0);
+
+       /*
+        * decrement ->i_nlink and update ->i_ctime
+        */
+       INODE_DEC_FIELD(object, i_nlink);
+       if (object->i_nlink == 1)
+               INODE_DEC_FIELD(object, i_nlink);
+       object->i_ctime = CURRENT_TIME;
+       return 0;
+}
+
+/* this is common implementation of owns_item method of file plugin
+   compare objectids of keys in inode and coord */
+int owns_item_common(const struct inode *inode,        /* object to check
+                                                * against */
+                    const coord_t * coord /* coord to check */ )
+{
+       reiser4_key item_key;
+       reiser4_key file_key;
+
+       assert("nikita-760", inode != NULL);
+       assert("nikita-761", coord != NULL);
+
+       return coord_is_existing_item(coord) &&
+           (get_key_objectid(build_sd_key(inode, &file_key)) ==
+            get_key_objectid(item_key_by_coord(coord, &item_key)));
+}
+
+/* this is common implementation of owns_item method of file plugin
+   for typical directory
+*/
+int owns_item_common_dir(const struct inode *inode,    /* object to check against */
+                        const coord_t * coord /* coord of item to check */ )
+{
+       reiser4_key item_key;
+
+       assert("nikita-1335", inode != NULL);
+       assert("nikita-1334", coord != NULL);
+
+       if (plugin_of_group(item_plugin_by_coord(coord), DIR_ENTRY_ITEM_TYPE))
+               return get_key_locality(item_key_by_coord(coord, &item_key)) ==
+                   get_inode_oid(inode);
+       else
+               return owns_item_common(inode, coord);
+}
+
+/* this is common implementation of can_add_link method of file plugin
+   checks whether yet another hard links to this object can be added
+*/
+int can_add_link_common(const struct inode *object /* object to check */ )
+{
+       assert("nikita-732", object != NULL);
+
+       /* inode->i_nlink is unsigned int, so just check for integer
+          overflow */
+       return object->i_nlink + 1 != 0;
+}
+
+/* this is common implementation of can_rem_link method of file plugin for
+   typical directory
+*/
+int can_rem_link_common_dir(const struct inode *inode)
+{
+       /* is_dir_empty() returns 0 is dir is empty */
+       return !is_dir_empty(inode);
+}
+
+/* this is common implementation of detach method of file plugin for typical
+   directory
+*/
+int reiser4_detach_common_dir(struct inode *child, struct inode *parent)
+{
+       dir_plugin *dplug;
+
+       dplug = inode_dir_plugin(child);
+       assert("nikita-2883", dplug != NULL);
+       assert("nikita-2884", dplug->detach != NULL);
+       return dplug->detach(child, parent);
+}
+
+/* this is common implementation of bind method of file plugin for typical
+   directory
+*/
+int reiser4_bind_common_dir(struct inode *child, struct inode *parent)
+{
+       dir_plugin *dplug;
+
+       dplug = inode_dir_plugin(child);
+       assert("nikita-2646", dplug != NULL);
+       return dplug->attach(child, parent);
+}
+
+static int process_truncate(struct inode *, __u64 size);
+
+/* this is common implementation of safelink method of file plugin
+ */
+int safelink_common(struct inode *object, reiser4_safe_link_t link, __u64 value)
+{
+       int result;
+
+       assert("vs-1705", get_current_context()->trans->atom == NULL);
+       if (link == SAFE_UNLINK)
+               /* nothing to do. iput() in the caller (process_safelink) will
+                * finish with file */
+               result = 0;
+       else if (link == SAFE_TRUNCATE)
+               result = process_truncate(object, value);
+       else {
+               warning("nikita-3438", "Unrecognized safe-link type: %i", link);
+               result = RETERR(-EIO);
+       }
+       return result;
+}
+
+/* this is common implementation of estimate.create method of file plugin
+   can be used when object creation involves insertion of one item (usually stat
+   data) into tree
+*/
+reiser4_block_nr estimate_create_common(const struct inode * object)
+{
+       return estimate_one_insert_item(reiser4_tree_by_inode(object));
+}
+
+/* this is common implementation of estimate.create method of file plugin for
+   typical directory
+   can be used when directory creation involves insertion of two items (usually
+   stat data and item containing "." and "..") into tree
+*/
+reiser4_block_nr estimate_create_common_dir(const struct inode * object)
+{
+       return 2 * estimate_one_insert_item(reiser4_tree_by_inode(object));
+}
+
+/* this is common implementation of estimate.update method of file plugin
+   can be used when stat data update does not do more than inserting a unit
+   into a stat data item which is probably true for most cases
+*/
+reiser4_block_nr estimate_update_common(const struct inode * inode)
+{
+       return estimate_one_insert_into_item(reiser4_tree_by_inode(inode));
+}
+
+/* this is common implementation of estimate.unlink method of file plugin
+ */
+reiser4_block_nr
+estimate_unlink_common(const struct inode * object UNUSED_ARG,
+                      const struct inode * parent UNUSED_ARG)
+{
+       return 0;
+}
+
+/* this is common implementation of estimate.unlink method of file plugin for
+   typical directory
+*/
+reiser4_block_nr
+estimate_unlink_common_dir(const struct inode * object,
+                          const struct inode * parent)
+{
+       dir_plugin *dplug;
+
+       dplug = inode_dir_plugin(object);
+       assert("nikita-2888", dplug != NULL);
+       assert("nikita-2887", dplug->estimate.unlink != NULL);
+       return dplug->estimate.unlink(object, parent);
+}
+
+char *wire_write_common(struct inode *inode, char *start)
+{
+       return build_inode_onwire(inode, start);
+}
+
+char *wire_read_common(char *addr, reiser4_object_on_wire * obj)
+{
+       return extract_obj_key_id_from_onwire(addr, &obj->u.std.key_id);
+}
+
+struct dentry *wire_get_common(struct super_block *sb,
+                              reiser4_object_on_wire * obj)
+{
+       struct inode *inode;
+       struct dentry *dentry;
+       reiser4_key key;
+
+       extract_key_from_id(&obj->u.std.key_id, &key);
+       inode = reiser4_iget(sb, &key, 1);
+       if (!IS_ERR(inode)) {
+               reiser4_iget_complete(inode);
+               dentry = d_alloc_anon(inode);
+               if (dentry == NULL) {
+                       iput(inode);
+                       dentry = ERR_PTR(-ENOMEM);
+               } else
+                       dentry->d_op = &get_super_private(sb)->ops.dentry;
+       } else if (PTR_ERR(inode) == -ENOENT)
+               /*
+                * inode wasn't found at the key encoded in the file
+                * handle. Hence, file handle is stale.
+                */
+               dentry = ERR_PTR(RETERR(-ESTALE));
+       else
+               dentry = (void *)inode;
+       return dentry;
+}
+
+int wire_size_common(struct inode *inode)
+{
+       return inode_onwire_size(inode);
+}
+
+void wire_done_common(reiser4_object_on_wire * obj)
+{
+       /* nothing to do */
+}
+
+/* helper function to print errors */
+static void key_warning(const reiser4_key * key /* key to print */ ,
+                       const struct inode *inode,
+                       int code /* error code to print */ )
+{
+       assert("nikita-716", key != NULL);
+
+       if (code != -ENOMEM) {
+               warning("nikita-717", "Error for inode %llu (%i)",
+                       (unsigned long long)get_key_objectid(key), code);
+               reiser4_print_key("for key", key);
+       }
+}
+
+/* NIKITA-FIXME-HANS: perhaps this function belongs in another file? */
+#if REISER4_DEBUG
+static void
+check_inode_seal(const struct inode *inode,
+                const coord_t * coord, const reiser4_key * key)
+{
+       reiser4_key unit_key;
+
+       unit_key_by_coord(coord, &unit_key);
+       assert("nikita-2752",
+              WITH_DATA_RET(coord->node, 1, keyeq(key, &unit_key)));
+       assert("nikita-2753", get_inode_oid(inode) == get_key_objectid(key));
+}
+
+static void check_sd_coord(coord_t * coord, const reiser4_key * key)
+{
+       reiser4_key ukey;
+
+       coord_clear_iplug(coord);
+       if (zload(coord->node))
+               return;
+
+       if (!coord_is_existing_unit(coord) ||
+           !item_plugin_by_coord(coord) ||
+           !keyeq(unit_key_by_coord(coord, &ukey), key) ||
+           (znode_get_level(coord->node) != LEAF_LEVEL) ||
+           !item_is_statdata(coord)) {
+               warning("nikita-1901", "Conspicuous seal");
+               reiser4_print_key("key", key);
+               print_coord("coord", coord, 1);
+               impossible("nikita-2877", "no way");
+       }
+       zrelse(coord->node);
+}
+
+#else
+#define check_inode_seal(inode, coord, key) noop
+#define check_sd_coord(coord, key) noop
+#endif
+
+/* insert new stat-data into tree. Called with inode state
+    locked. Return inode state locked. */
+static int insert_new_sd(struct inode *inode /* inode to create sd for */ )
+{
+       int result;
+       reiser4_key key;
+       coord_t coord;
+       reiser4_item_data data;
+       char *area;
+       reiser4_inode *ref;
+       lock_handle lh;
+       oid_t oid;
+
+       assert("nikita-723", inode != NULL);
+       assert("nikita-3406", reiser4_inode_get_flag(inode, REISER4_NO_SD));
+
+       ref = reiser4_inode_data(inode);
+       spin_lock_inode(inode);
+
+       if (ref->plugin_mask != 0)
+               /* inode has non-standard plugins */
+               inode_set_extension(inode, PLUGIN_STAT);
+       /*
+        * prepare specification of new item to be inserted
+        */
+
+       data.iplug = inode_sd_plugin(inode);
+       data.length = data.iplug->s.sd.save_len(inode);
+       spin_unlock_inode(inode);
+
+       data.data = NULL;
+       data.user = 0;
+/* could be optimized for case where there is only one node format in
+ * use in the filesystem, probably there are lots of such
+ * places we could optimize for only one node layout.... -Hans */
+       if (data.length > reiser4_tree_by_inode(inode)->nplug->max_item_size()){
+               /* This is silly check, but we don't know actual node where
+                  insertion will go into. */
+               return RETERR(-ENAMETOOLONG);
+       }
+       oid = oid_allocate(inode->i_sb);
+/* NIKITA-FIXME-HANS: what is your opinion on whether this error check should be encapsulated into oid_allocate? */
+       if (oid == ABSOLUTE_MAX_OID)
+               return RETERR(-EOVERFLOW);
+
+       set_inode_oid(inode, oid);
+
+       coord_init_zero(&coord);
+       init_lh(&lh);
+
+       result = insert_by_key(reiser4_tree_by_inode(inode),
+                              build_sd_key(inode, &key), &data, &coord, &lh,
+                              /* stat data lives on a leaf level */
+                              LEAF_LEVEL, CBK_UNIQUE);
+
+       /* we don't want to re-check that somebody didn't insert
+          stat-data while we were doing io, because if it did,
+          insert_by_key() returned error. */
+       /* but what _is_ possible is that plugin for inode's stat-data,
+          list of non-standard plugins or their state would change
+          during io, so that stat-data wouldn't fit into sd. To avoid
+          this race we keep inode_state lock. This lock has to be
+          taken each time you access inode in a way that would cause
+          changes in sd size: changing plugins etc.
+        */
+
+       if (result == IBK_INSERT_OK) {
+               coord_clear_iplug(&coord);
+               result = zload(coord.node);
+               if (result == 0) {
+                       /* have we really inserted stat data? */
+                       assert("nikita-725", item_is_statdata(&coord));
+
+                       /* inode was just created. It is inserted into hash
+                          table, but no directory entry was yet inserted into
+                          parent. So, inode is inaccessible through
+                          ->lookup(). All places that directly grab inode
+                          from hash-table (like old knfsd), should check
+                          IMMUTABLE flag that is set by common_create_child.
+                        */
+                       assert("nikita-3240", data.iplug != NULL);
+                       assert("nikita-3241", data.iplug->s.sd.save != NULL);
+                       area = item_body_by_coord(&coord);
+                       result = data.iplug->s.sd.save(inode, &area);
+                       znode_make_dirty(coord.node);
+                       if (result == 0) {
+                               /* object has stat-data now */
+                               reiser4_inode_clr_flag(inode, REISER4_NO_SD);
+                               reiser4_inode_set_flag(inode, REISER4_SDLEN_KNOWN);
+                               /* initialise stat-data seal */
+                               reiser4_seal_init(&ref->sd_seal, &coord, &key);
+                               ref->sd_coord = coord;
+                               check_inode_seal(inode, &coord, &key);
+                       } else if (result != -ENOMEM)
+                               /*
+                                * convert any other error code to -EIO to
+                                * avoid confusing user level with unexpected
+                                * errors.
+                                */
+                               result = RETERR(-EIO);
+                       zrelse(coord.node);
+               }
+       }
+       done_lh(&lh);
+
+       if (result != 0)
+               key_warning(&key, inode, result);
+       else
+               oid_count_allocated();
+
+       return result;
+}
+
+/* find sd of inode in a tree, deal with errors */
+int lookup_sd(struct inode *inode /* inode to look sd for */ ,
+             znode_lock_mode lock_mode /* lock mode */ ,
+             coord_t * coord /* resulting coord */ ,
+             lock_handle * lh /* resulting lock handle */ ,
+             const reiser4_key * key /* resulting key */ ,
+             int silent)
+{
+       int result;
+       __u32 flags;
+
+       assert("nikita-1692", inode != NULL);
+       assert("nikita-1693", coord != NULL);
+       assert("nikita-1694", key != NULL);
+
+       /* look for the object's stat data in a tree.
+          This returns in "node" pointer to a locked znode and in "pos"
+          position of an item found in node. Both are only valid if
+          coord_found is returned. */
+       flags = (lock_mode == ZNODE_WRITE_LOCK) ? CBK_FOR_INSERT : 0;
+       flags |= CBK_UNIQUE;
+       /*
+        * traverse tree to find stat data. We cannot use vroot here, because
+        * it only covers _body_ of the file, and stat data don't belong
+        * there.
+        */
+       result = coord_by_key(reiser4_tree_by_inode(inode),
+                             key,
+                             coord,
+                             lh,
+                             lock_mode,
+                             FIND_EXACT, LEAF_LEVEL, LEAF_LEVEL, flags, NULL);
+       if (REISER4_DEBUG && result == 0)
+               check_sd_coord(coord, key);
+
+       if (result != 0 && !silent)
+               key_warning(key, inode, result);
+       return result;
+}
+
+static int
+locate_inode_sd(struct inode *inode,
+               reiser4_key * key, coord_t * coord, lock_handle * lh)
+{
+       reiser4_inode *state;
+       seal_t seal;
+       int result;
+
+       assert("nikita-3483", inode != NULL);
+
+       state = reiser4_inode_data(inode);
+       spin_lock_inode(inode);
+       *coord = state->sd_coord;
+       coord_clear_iplug(coord);
+       seal = state->sd_seal;
+       spin_unlock_inode(inode);
+
+       build_sd_key(inode, key);
+       if (reiser4_seal_is_set(&seal)) {
+               /* first, try to use seal */
+               result = reiser4_seal_validate(&seal,
+                                              coord,
+                                              key,
+                                              lh, ZNODE_WRITE_LOCK,
+                                              ZNODE_LOCK_LOPRI);
+               if (result == 0)
+                       check_sd_coord(coord, key);
+       } else
+               result = -E_REPEAT;
+
+       if (result != 0) {
+               coord_init_zero(coord);
+               result = lookup_sd(inode, ZNODE_WRITE_LOCK, coord, lh, key, 0);
+       }
+       return result;
+}
+
+#if REISER4_DEBUG
+static int all_but_offset_key_eq(const reiser4_key * k1, const reiser4_key * k2)
+{
+       return (get_key_locality(k1) == get_key_locality(k2) &&
+               get_key_type(k1) == get_key_type(k2) &&
+               get_key_band(k1) == get_key_band(k2) &&
+               get_key_ordering(k1) == get_key_ordering(k2) &&
+               get_key_objectid(k1) == get_key_objectid(k2));
+}
+
+#include "../tree_walk.h"
+
+/* make some checks before and after stat-data resize operation */
+static int check_sd_resize(struct inode * inode, coord_t * coord,
+                          int length, int progress /* 1 means after resize */)
+{
+       int ret = 0;
+       lock_handle left_lock;
+       coord_t left_coord;
+       reiser4_key left_key;
+       reiser4_key key;
+
+       if (inode_file_plugin(inode) !=
+           file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID))
+               return 0;
+       if (!length)
+               return 0;
+       if (coord->item_pos != 0)
+               return 0;
+
+       init_lh(&left_lock);
+       ret = reiser4_get_left_neighbor(&left_lock,
+                                       coord->node,
+                                       ZNODE_WRITE_LOCK,
+                                       GN_CAN_USE_UPPER_LEVELS);
+       if (ret == -E_REPEAT || ret == -E_NO_NEIGHBOR ||
+           ret == -ENOENT || ret == -EINVAL
+           || ret == -E_DEADLOCK) {
+               ret = 0;
+               goto exit;
+       }
+       ret = zload(left_lock.node);
+       if (ret)
+               goto exit;
+       coord_init_last_unit(&left_coord, left_lock.node);
+       item_key_by_coord(&left_coord, &left_key);
+       item_key_by_coord(coord, &key);
+
+       if (all_but_offset_key_eq(&key, &left_key))
+               /* corruption occured */
+               ret = 1;
+       zrelse(left_lock.node);
+ exit:
+       done_lh(&left_lock);
+       return ret;
+}
+#endif
+
+/* update stat-data at @coord */
+static int
+update_sd_at(struct inode *inode, coord_t * coord, reiser4_key * key,
+            lock_handle * lh)
+{
+       int result;
+       reiser4_item_data data;
+       char *area;
+       reiser4_inode *state;
+       znode *loaded;
+
+       state = reiser4_inode_data(inode);
+
+       coord_clear_iplug(coord);
+       result = zload(coord->node);
+       if (result != 0)
+               return result;
+       loaded = coord->node;
+
+       spin_lock_inode(inode);
+       assert("nikita-728", inode_sd_plugin(inode) != NULL);
+       data.iplug = inode_sd_plugin(inode);
+
+       /* if inode has non-standard plugins, add appropriate stat data
+        * extension */
+       if (state->extmask & (1 << PLUGIN_STAT)) {
+               if (state->plugin_mask == 0)
+                       inode_clr_extension(inode, PLUGIN_STAT);
+       } else if (state->plugin_mask != 0)
+               inode_set_extension(inode, PLUGIN_STAT);
+
+       if (state->extmask & (1 << HEIR_STAT)) {
+               if (state->heir_mask == 0)
+                       inode_clr_extension(inode, HEIR_STAT);
+       } else if (state->heir_mask != 0)
+                       inode_set_extension(inode, HEIR_STAT);
+
+       /* data.length is how much space to add to (or remove
+          from if negative) sd */
+       if (!reiser4_inode_get_flag(inode, REISER4_SDLEN_KNOWN)) {
+               /* recalculate stat-data length */
+               data.length =
+                   data.iplug->s.sd.save_len(inode) -
+                   item_length_by_coord(coord);
+               reiser4_inode_set_flag(inode, REISER4_SDLEN_KNOWN);
+       } else
+               data.length = 0;
+       spin_unlock_inode(inode);
+
+       /* if on-disk stat data is of different length than required
+          for this inode, resize it */
+
+       if (data.length != 0) {
+               data.data = NULL;
+               data.user = 0;
+
+               assert("edward-1441",
+                      !check_sd_resize(inode, coord,
+                                       data.length, 0/* before resize */));
+
+               /* insertion code requires that insertion point (coord) was
+                * between units. */
+               coord->between = AFTER_UNIT;
+               result = reiser4_resize_item(coord, &data, key, lh,
+                                            COPI_DONT_SHIFT_LEFT);
+               if (result != 0) {
+                       key_warning(key, inode, result);
+                       zrelse(loaded);
+                       return result;
+               }
+               if (loaded != coord->node) {
+                 /* reiser4_resize_item moved coord to another node.
+                    Zload it */
+                       zrelse(loaded);
+                       coord_clear_iplug(coord);
+                       result = zload(coord->node);
+                       if (result != 0)
+                               return result;
+                       loaded = coord->node;
+               }
+               assert("edward-1442",
+                      !check_sd_resize(inode, coord,
+                                       data.length, 1/* after resize */));
+       }
+       area = item_body_by_coord(coord);
+       spin_lock_inode(inode);
+       result = data.iplug->s.sd.save(inode, &area);
+       znode_make_dirty(coord->node);
+
+       /* re-initialise stat-data seal */
+
+       /*
+        * coord.between was possibly skewed from AT_UNIT when stat-data size
+        * was changed and new extensions were pasted into item.
+        */
+       coord->between = AT_UNIT;
+       reiser4_seal_init(&state->sd_seal, coord, key);
+       state->sd_coord = *coord;
+       spin_unlock_inode(inode);
+       check_inode_seal(inode, coord, key);
+       zrelse(loaded);
+       return result;
+}
+
+/* Update existing stat-data in a tree. Called with inode state locked. Return
+   inode state locked. */
+static int update_sd(struct inode *inode /* inode to update sd for */ )
+{
+       int result;
+       reiser4_key key;
+       coord_t coord;
+       lock_handle lh;
+
+       assert("nikita-726", inode != NULL);
+
+       /* no stat-data, nothing to update?! */
+       assert("nikita-3482", !reiser4_inode_get_flag(inode, REISER4_NO_SD));
+
+       init_lh(&lh);
+
+       result = locate_inode_sd(inode, &key, &coord, &lh);
+       if (result == 0)
+               result = update_sd_at(inode, &coord, &key, &lh);
+       done_lh(&lh);
+
+       return result;
+}
+
+/* helper for reiser4_delete_object_common and reiser4_delete_dir_common.
+   Remove object stat data. Space for that must be reserved by caller before
+*/
+static int
+common_object_delete_no_reserve(struct inode *inode /* object to remove */ )
+{
+       int result;
+
+       assert("nikita-1477", inode != NULL);
+
+       if (!reiser4_inode_get_flag(inode, REISER4_NO_SD)) {
+               reiser4_key sd_key;
+
+               DQUOT_FREE_INODE(inode);
+               DQUOT_DROP(inode);
+
+               build_sd_key(inode, &sd_key);
+               result =
+                   reiser4_cut_tree(reiser4_tree_by_inode(inode),
+                                    &sd_key, &sd_key, NULL, 0);
+               if (result == 0) {
+                       reiser4_inode_set_flag(inode, REISER4_NO_SD);
+                       result = oid_release(inode->i_sb, get_inode_oid(inode));
+                       if (result == 0) {
+                               oid_count_released();
+
+                               result = safe_link_del(reiser4_tree_by_inode(inode),
+                                                      get_inode_oid(inode),
+                                                      SAFE_UNLINK);
+                       }
+               }
+       } else
+               result = 0;
+       return result;
+}
+
+/* helper for safelink_common */
+static int process_truncate(struct inode *inode, __u64 size)
+{
+       int result;
+       struct iattr attr;
+       file_plugin *fplug;
+       reiser4_context *ctx;
+       struct dentry dentry;
+
+       assert("vs-21", is_in_reiser4_context());
+       ctx = reiser4_init_context(inode->i_sb);
+       assert("vs-22", !IS_ERR(ctx));
+
+       attr.ia_size = size;
+       attr.ia_valid = ATTR_SIZE | ATTR_CTIME;
+       fplug = inode_file_plugin(inode);
+
+       mutex_lock(&inode->i_mutex);
+       assert("vs-1704", get_current_context()->trans->atom == NULL);
+       dentry.d_inode = inode;
+       result = inode->i_op->setattr(&dentry, &attr);
+       mutex_unlock(&inode->i_mutex);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+
+       return result;
+}
+
+/*
+  Local variables:
+  c-indentation-style: "K&R"
+  mode-name: "LC"
+  c-basic-offset: 8
+  tab-width: 8
+  fill-column: 80
+  scroll-step: 1
+  End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/hash.c linux-2.6.20/fs/reiser4/plugin/hash.c
--- linux-2.6.20.orig/fs/reiser4/plugin/hash.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/hash.c       2007-05-06 14:50:43.791004471 +0400
@@ -0,0 +1,353 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Hash functions */
+
+#include "../debug.h"
+#include "plugin_header.h"
+#include "plugin.h"
+#include "../super.h"
+#include "../inode.h"
+
+#include <linux/types.h>
+
+/* old rupasov (yura) hash */
+static __u64 hash_rupasov(const unsigned char *name /* name to hash */ ,
+                         int len /* @name's length */ )
+{
+       int i;
+       int j;
+       int pow;
+       __u64 a;
+       __u64 c;
+
+       assert("nikita-672", name != NULL);
+       assert("nikita-673", len >= 0);
+
+       for (pow = 1, i = 1; i < len; ++i)
+               pow = pow * 10;
+
+       if (len == 1)
+               a = name[0] - 48;
+       else
+               a = (name[0] - 48) * pow;
+
+       for (i = 1; i < len; ++i) {
+               c = name[i] - 48;
+               for (pow = 1, j = i; j < len - 1; ++j)
+                       pow = pow * 10;
+               a = a + c * pow;
+       }
+       for (; i < 40; ++i) {
+               c = '0' - 48;
+               for (pow = 1, j = i; j < len - 1; ++j)
+                       pow = pow * 10;
+               a = a + c * pow;
+       }
+
+       for (; i < 256; ++i) {
+               c = i;
+               for (pow = 1, j = i; j < len - 1; ++j)
+                       pow = pow * 10;
+               a = a + c * pow;
+       }
+
+       a = a << 7;
+       return a;
+}
+
+/* r5 hash */
+static __u64 hash_r5(const unsigned char *name /* name to hash */ ,
+                    int len UNUSED_ARG /* @name's length */ )
+{
+       __u64 a = 0;
+
+       assert("nikita-674", name != NULL);
+       assert("nikita-675", len >= 0);
+
+       while (*name) {
+               a += *name << 4;
+               a += *name >> 4;
+               a *= 11;
+               name++;
+       }
+       return a;
+}
+
+/* Keyed 32-bit hash function using TEA in a Davis-Meyer function
+     H0 = Key
+     Hi = E Mi(Hi-1) + Hi-1
+
+   (see Applied Cryptography, 2nd edition, p448).
+
+   Jeremy Fitzhardinge <jeremy@zip.com.au> 1998
+
+   Jeremy has agreed to the contents of reiserfs/README. -Hans
+
+   This code was blindly upgraded to __u64 by s/__u32/__u64/g.
+*/
+static __u64 hash_tea(const unsigned char *name /* name to hash */ ,
+                     int len /* @name's length */ )
+{
+       __u64 k[] = { 0x9464a485u, 0x542e1a94u, 0x3e846bffu, 0xb75bcfc3u };
+
+       __u64 h0 = k[0], h1 = k[1];
+       __u64 a, b, c, d;
+       __u64 pad;
+       int i;
+
+       assert("nikita-676", name != NULL);
+       assert("nikita-677", len >= 0);
+
+#define DELTA 0x9E3779B9u
+#define FULLROUNDS 10          /* 32 is overkill, 16 is strong crypto */
+#define PARTROUNDS 6           /* 6 gets complete mixing */
+
+/* a, b, c, d - data; h0, h1 - accumulated hash */
+#define TEACORE(rounds)                                                        \
+       do {                                                            \
+               __u64 sum = 0;                                          \
+               int n = rounds;                                         \
+               __u64 b0, b1;                                           \
+                                                                       \
+               b0 = h0;                                                \
+               b1 = h1;                                                \
+                                                                       \
+               do                                                      \
+               {                                                       \
+                       sum += DELTA;                                   \
+                       b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); \
+                       b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); \
+               } while(--n);                                           \
+                                                                       \
+               h0 += b0;                                               \
+               h1 += b1;                                               \
+       } while(0)
+
+       pad = (__u64) len | ((__u64) len << 8);
+       pad |= pad << 16;
+
+       while (len >= 16) {
+               a = (__u64) name[0] | (__u64) name[1] << 8 | (__u64) name[2] <<
+                   16 | (__u64) name[3] << 24;
+               b = (__u64) name[4] | (__u64) name[5] << 8 | (__u64) name[6] <<
+                   16 | (__u64) name[7] << 24;
+               c = (__u64) name[8] | (__u64) name[9] << 8 | (__u64) name[10] <<
+                   16 | (__u64) name[11] << 24;
+               d = (__u64) name[12] | (__u64) name[13] << 8 | (__u64) name[14]
+                   << 16 | (__u64) name[15] << 24;
+
+               TEACORE(PARTROUNDS);
+
+               len -= 16;
+               name += 16;
+       }
+
+       if (len >= 12) {
+               //assert(len < 16);
+               if (len >= 16)
+                       *(int *)0 = 0;
+
+               a = (__u64) name[0] | (__u64) name[1] << 8 | (__u64) name[2] <<
+                   16 | (__u64) name[3] << 24;
+               b = (__u64) name[4] | (__u64) name[5] << 8 | (__u64) name[6] <<
+                   16 | (__u64) name[7] << 24;
+               c = (__u64) name[8] | (__u64) name[9] << 8 | (__u64) name[10] <<
+                   16 | (__u64) name[11] << 24;
+
+               d = pad;
+               for (i = 12; i < len; i++) {
+                       d <<= 8;
+                       d |= name[i];
+               }
+       } else if (len >= 8) {
+               //assert(len < 12);
+               if (len >= 12)
+                       *(int *)0 = 0;
+               a = (__u64) name[0] | (__u64) name[1] << 8 | (__u64) name[2] <<
+                   16 | (__u64) name[3] << 24;
+               b = (__u64) name[4] | (__u64) name[5] << 8 | (__u64) name[6] <<
+                   16 | (__u64) name[7] << 24;
+
+               c = d = pad;
+               for (i = 8; i < len; i++) {
+                       c <<= 8;
+                       c |= name[i];
+               }
+       } else if (len >= 4) {
+               //assert(len < 8);
+               if (len >= 8)
+                       *(int *)0 = 0;
+               a = (__u64) name[0] | (__u64) name[1] << 8 | (__u64) name[2] <<
+                   16 | (__u64) name[3] << 24;
+
+               b = c = d = pad;
+               for (i = 4; i < len; i++) {
+                       b <<= 8;
+                       b |= name[i];
+               }
+       } else {
+               //assert(len < 4);
+               if (len >= 4)
+                       *(int *)0 = 0;
+               a = b = c = d = pad;
+               for (i = 0; i < len; i++) {
+                       a <<= 8;
+                       a |= name[i];
+               }
+       }
+
+       TEACORE(FULLROUNDS);
+
+/*     return 0;*/
+       return h0 ^ h1;
+
+}
+
+/* classical 64 bit Fowler/Noll/Vo-1 (FNV-1) hash.
+
+   See http://www.isthe.com/chongo/tech/comp/fnv/ for details.
+
+   Excerpts:
+
+     FNV hashes are designed to be fast while maintaining a low collision
+     rate.
+
+     [This version also seems to preserve lexicographical order locally.]
+
+     FNV hash algorithms and source code have been released into the public
+     domain.
+
+*/
+static __u64 hash_fnv1(const unsigned char *name /* name to hash */ ,
+                      int len UNUSED_ARG /* @name's length */ )
+{
+       unsigned long long a = 0xcbf29ce484222325ull;
+       const unsigned long long fnv_64_prime = 0x100000001b3ull;
+
+       assert("nikita-678", name != NULL);
+       assert("nikita-679", len >= 0);
+
+       /* FNV-1 hash each octet in the buffer */
+       for (; *name; ++name) {
+               /* multiply by the 32 bit FNV magic prime mod 2^64 */
+               a *= fnv_64_prime;
+               /* xor the bottom with the current octet */
+               a ^= (unsigned long long)(*name);
+       }
+       /* return our new hash value */
+       return a;
+}
+
+/* degenerate hash function used to simplify testing of non-unique key
+   handling */
+static __u64 hash_deg(const unsigned char *name UNUSED_ARG /* name to hash */ ,
+                     int len UNUSED_ARG /* @name's length */ )
+{
+       return 0xc0c0c0c010101010ull;
+}
+
+static int change_hash(struct inode *inode,
+                      reiser4_plugin * plugin,
+                      pset_member memb)
+{
+       int result;
+
+       assert("nikita-3503", inode != NULL);
+       assert("nikita-3504", plugin != NULL);
+
+       assert("nikita-3505", is_reiser4_inode(inode));
+       assert("nikita-3507", plugin->h.type_id == REISER4_HASH_PLUGIN_TYPE);
+
+       if (!plugin_of_group(inode_file_plugin(inode), REISER4_DIRECTORY_FILE))
+               return RETERR(-EINVAL);
+
+       result = 0;
+       if (inode_hash_plugin(inode) == NULL ||
+           inode_hash_plugin(inode)->h.id != plugin->h.id) {
+               if (is_dir_empty(inode) == 0)
+                       result = aset_set_unsafe(&reiser4_inode_data(inode)->pset,
+                                                PSET_HASH, plugin);
+               else
+                       result = RETERR(-ENOTEMPTY);
+
+       }
+       return result;
+}
+
+static reiser4_plugin_ops hash_plugin_ops = {
+       .init = NULL,
+       .load = NULL,
+       .save_len = NULL,
+       .save = NULL,
+       .change = change_hash
+};
+
+/* hash plugins */
+hash_plugin hash_plugins[LAST_HASH_ID] = {
+       [RUPASOV_HASH_ID] = {
+               .h = {
+                       .type_id = REISER4_HASH_PLUGIN_TYPE,
+                       .id = RUPASOV_HASH_ID,
+                       .pops = &hash_plugin_ops,
+                       .label = "rupasov",
+                       .desc = "Original Yura's hash",
+                       .linkage = {NULL, NULL}
+               },
+               .hash = hash_rupasov
+       },
+       [R5_HASH_ID] = {
+               .h = {
+                       .type_id = REISER4_HASH_PLUGIN_TYPE,
+                       .id = R5_HASH_ID,
+                       .pops = &hash_plugin_ops,
+                       .label = "r5",
+                       .desc = "r5 hash",
+                       .linkage = {NULL, NULL}
+               },
+               .hash = hash_r5
+       },
+       [TEA_HASH_ID] = {
+               .h = {
+                       .type_id = REISER4_HASH_PLUGIN_TYPE,
+                       .id = TEA_HASH_ID,
+                       .pops = &hash_plugin_ops,
+                       .label = "tea",
+                       .desc = "tea hash",
+                       .linkage = {NULL, NULL}
+               },
+               .hash = hash_tea
+       },
+       [FNV1_HASH_ID] = {
+               .h = {
+                       .type_id = REISER4_HASH_PLUGIN_TYPE,
+                       .id = FNV1_HASH_ID,
+                       .pops = &hash_plugin_ops,
+                       .label = "fnv1",
+                       .desc = "fnv1 hash",
+                       .linkage = {NULL, NULL}
+               },
+               .hash = hash_fnv1
+       },
+       [DEGENERATE_HASH_ID] = {
+               .h = {
+                       .type_id = REISER4_HASH_PLUGIN_TYPE,
+                       .id = DEGENERATE_HASH_ID,
+                       .pops = &hash_plugin_ops,
+                       .label = "degenerate hash",
+                       .desc = "Degenerate hash: only for testing",
+                       .linkage = {NULL, NULL}
+               },
+               .hash = hash_deg
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/inode_ops.c linux-2.6.20/fs/reiser4/plugin/inode_ops.c
--- linux-2.6.20.orig/fs/reiser4/plugin/inode_ops.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/inode_ops.c  2007-05-06 14:50:43.795005721 +0400
@@ -0,0 +1,897 @@
+/*
+ * Copyright 2005 by Hans Reiser, licensing governed by reiser4/README
+ */
+
+/*
+ * this file contains typical implementations for most of methods of struct
+ * inode_operations
+ */
+
+#include "../inode.h"
+#include "../safe_link.h"
+
+#include <linux/quotaops.h>
+#include <linux/namei.h>
+
+static int create_vfs_object(struct inode *parent, struct dentry *dentry,
+                     reiser4_object_create_data *data);
+
+/**
+ * reiser4_create_common - create of inode operations
+ * @parent: inode of parent directory
+ * @dentry: dentry of new object to create
+ * @mode: the permissions to use
+ * @nameidata:
+ *
+ * This is common implementation of vfs's create method of struct
+ * inode_operations.
+ * Creates regular file using file plugin from parent directory plugin set.
+ */
+int reiser4_create_common(struct inode *parent, struct dentry *dentry,
+                         int mode, struct nameidata *nameidata)
+{
+       reiser4_object_create_data data;
+       file_plugin *fplug;
+
+       memset(&data, 0, sizeof data);
+       data.mode = S_IFREG | mode;
+       fplug = child_create_plugin(parent) ? : inode_create_plugin(parent);
+       if (!plugin_of_group(fplug, REISER4_REGULAR_FILE)) {
+               warning("vpf-1900", "'%s' is not a regular file plugin.",
+                       fplug->h.label);
+               return RETERR(-EIO);
+       }
+       data.id = fplug->h.id;
+       return create_vfs_object(parent, dentry, &data);
+}
+
+int reiser4_lookup_name(struct inode *dir, struct dentry *, reiser4_key *);
+void check_light_weight(struct inode *inode, struct inode *parent);
+
+/**
+ * reiser4_lookup_common - lookup of inode operations
+ * @parent: inode of directory to lookup into
+ * @dentry: name to look for
+ * @nameidata:
+ *
+ * This is common implementation of vfs's lookup method of struct
+ * inode_operations.
+ */
+struct dentry *reiser4_lookup_common(struct inode *parent,
+                                    struct dentry *dentry,
+                                    struct nameidata *nameidata)
+{
+       reiser4_context *ctx;
+       int result;
+       struct dentry *new;
+       struct inode *inode;
+       reiser4_dir_entry_desc entry;
+
+       ctx = reiser4_init_context(parent->i_sb);
+       if (IS_ERR(ctx))
+               return (struct dentry *)ctx;
+
+       /* set up operations on dentry. */
+       dentry->d_op = &get_super_private(parent->i_sb)->ops.dentry;
+
+       result = reiser4_lookup_name(parent, dentry, &entry.key);
+       if (result) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               if (result == -ENOENT) {
+                       /* object not found */
+                       if (!IS_DEADDIR(parent))
+                               d_add(dentry, NULL);
+                       return NULL;
+               }
+               return ERR_PTR(result);
+       }
+
+       inode = reiser4_iget(parent->i_sb, &entry.key, 0);
+       if (IS_ERR(inode)) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return ERR_PTR(PTR_ERR(inode));
+       }
+
+       /* success */
+       check_light_weight(inode, parent);
+       new = d_splice_alias(inode, dentry);
+       reiser4_iget_complete(inode);
+
+       /* prevent balance_dirty_pages() from being called: we don't want to
+        * do this under directory i_mutex. */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return new;
+}
+
+static reiser4_block_nr common_estimate_link(struct inode *parent,
+                                            struct inode *object);
+int reiser4_update_dir(struct inode *);
+
+/**
+ * reiser4_link_common - link of inode operations
+ * @existing: dentry of object which is to get new name
+ * @parent: directory where new name is to be created
+ * @newname: new name
+ *
+ * This is common implementation of vfs's link method of struct
+ * inode_operations.
+ */
+int reiser4_link_common(struct dentry *existing, struct inode *parent,
+                       struct dentry *newname)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *object;
+       dir_plugin *parent_dplug;
+       reiser4_dir_entry_desc entry;
+       reiser4_object_create_data data;
+       reiser4_block_nr reserve;
+
+       ctx = reiser4_init_context(parent->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       assert("nikita-1431", existing != NULL);
+       assert("nikita-1432", parent != NULL);
+       assert("nikita-1433", newname != NULL);
+
+       object = existing->d_inode;
+       assert("nikita-1434", object != NULL);
+
+       /* check for race with create_object() */
+       if (reiser4_inode_get_flag(object, REISER4_IMMUTABLE)) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return RETERR(-E_REPEAT);
+       }
+
+       parent_dplug = inode_dir_plugin(parent);
+
+       memset(&entry, 0, sizeof entry);
+       entry.obj = object;
+
+       data.mode = object->i_mode;
+       data.id = inode_file_plugin(object)->h.id;
+
+       reserve = common_estimate_link(parent, existing->d_inode);
+       if ((__s64) reserve < 0) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return reserve;
+       }
+
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT)) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return RETERR(-ENOSPC);
+       }
+
+       /*
+        * Subtle race handling: sys_link() doesn't take i_mutex on @parent. It
+        * means that link(2) can race against unlink(2) or rename(2), and
+        * inode is dead (->i_nlink == 0) when reiser4_link() is entered.
+        *
+        * For such inode we have to undo special processing done in
+        * reiser4_unlink() viz. creation of safe-link.
+        */
+       if (unlikely(object->i_nlink == 0)) {
+               result = safe_link_del(reiser4_tree_by_inode(object),
+                                      get_inode_oid(object), SAFE_UNLINK);
+               if (result != 0) {
+                       context_set_commit_async(ctx);
+                       reiser4_exit_context(ctx);
+                       return result;
+               }
+       }
+
+       /* increment nlink of @existing and update its stat data */
+       result = reiser4_add_nlink(object, parent, 1);
+       if (result == 0) {
+               /* add entry to the parent */
+               result =
+                   parent_dplug->add_entry(parent, newname, &data, &entry);
+               if (result != 0) {
+                       /* failed to add entry to the parent, decrement nlink
+                          of @existing */
+                       reiser4_del_nlink(object, parent, 1);
+                       /*
+                        * now, if that failed, we have a file with too big
+                        * nlink---space leak, much better than directory
+                        * entry pointing to nowhere
+                        */
+               }
+       }
+       if (result == 0) {
+               atomic_inc(&object->i_count);
+               /*
+                * Upon successful completion, link() shall mark for update
+                * the st_ctime field of the file. Also, the st_ctime and
+                * st_mtime fields of the directory that contains the new
+                * entry shall be marked for update. --SUS
+                */
+               result = reiser4_update_dir(parent);
+       }
+       if (result == 0)
+               d_instantiate(newname, existing->d_inode);
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+static int unlink_check_and_grab(struct inode *parent, struct dentry *victim);
+
+/**
+ * reiser4_unlink_common - unlink of inode operations
+ * @parent: inode of directory to remove name from
+ * @victim: name to be removed
+ *
+ * This is common implementation of vfs's unlink method of struct
+ * inode_operations.
+ */
+int reiser4_unlink_common(struct inode *parent, struct dentry *victim)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *object;
+       file_plugin *fplug;
+
+       ctx = reiser4_init_context(parent->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       object = victim->d_inode;
+       fplug = inode_file_plugin(object);
+       assert("nikita-2882", fplug->detach != NULL);
+
+       result = unlink_check_and_grab(parent, victim);
+       if (result != 0) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       result = fplug->detach(object, parent);
+       if (result == 0) {
+               dir_plugin *parent_dplug;
+               reiser4_dir_entry_desc entry;
+
+               parent_dplug = inode_dir_plugin(parent);
+               memset(&entry, 0, sizeof entry);
+
+               /* first, delete directory entry */
+               result = parent_dplug->rem_entry(parent, victim, &entry);
+               if (result == 0) {
+                       /*
+                        * if name was removed successfully, we _have_ to
+                        * return 0 from this function, because upper level
+                        * caller (vfs_{rmdir,unlink}) expect this.
+                        *
+                        * now that directory entry is removed, update
+                        * stat-data
+                        */
+                       reiser4_del_nlink(object, parent, 1);
+                       /*
+                        * Upon successful completion, unlink() shall mark for
+                        * update the st_ctime and st_mtime fields of the
+                        * parent directory. Also, if the file's link count is
+                        * not 0, the st_ctime field of the file shall be
+                        * marked for update. --SUS
+                        */
+                       reiser4_update_dir(parent);
+                       /* add safe-link for this file */
+                       if (object->i_nlink == 0)
+                               safe_link_add(object, SAFE_UNLINK);
+               }
+       }
+
+       if (unlikely(result != 0)) {
+               if (result != -ENOMEM)
+                       warning("nikita-3398", "Cannot unlink %llu (%i)",
+                               (unsigned long long)get_inode_oid(object),
+                               result);
+               /* if operation failed commit pending inode modifications to
+                * the stat-data */
+               reiser4_update_sd(object);
+               reiser4_update_sd(parent);
+       }
+
+       reiser4_release_reserved(object->i_sb);
+
+       /* @object's i_ctime was updated by ->rem_link() method(). */
+
+       /* @victim can be already removed from the disk by this time. Inode is
+          then marked so that iput() wouldn't try to remove stat data. But
+          inode itself is still there.
+        */
+
+       /*
+        * we cannot release directory semaphore here, because name has
+        * already been deleted, but dentry (@victim) still exists.  Prevent
+        * balance_dirty_pages() from being called on exiting this context: we
+        * don't want to do this under directory i_mutex.
+        */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/**
+ * reiser4_symlink_common - symlink of inode operations
+ * @parent: inode of parent directory
+ * @dentry: dentry of object to be created
+ * @linkname: string symlink is to contain
+ *
+ * This is common implementation of vfs's symlink method of struct
+ * inode_operations.
+ * Creates object using file plugin SYMLINK_FILE_PLUGIN_ID.
+ */
+int reiser4_symlink_common(struct inode *parent, struct dentry *dentry,
+                          const char *linkname)
+{
+       reiser4_object_create_data data;
+
+       memset(&data, 0, sizeof data);
+       data.name = linkname;
+       data.id = SYMLINK_FILE_PLUGIN_ID;
+       data.mode = S_IFLNK | S_IRWXUGO;
+       return create_vfs_object(parent, dentry, &data);
+}
+
+/**
+ * reiser4_mkdir_common - mkdir of inode operations
+ * @parent: inode of parent directory
+ * @dentry: dentry of object to be created
+ * @mode: the permissions to use
+ *
+ * This is common implementation of vfs's mkdir method of struct
+ * inode_operations.
+ * Creates object using file plugin DIRECTORY_FILE_PLUGIN_ID.
+ */
+int reiser4_mkdir_common(struct inode *parent, struct dentry *dentry, int mode)
+{
+       reiser4_object_create_data data;
+
+       memset(&data, 0, sizeof data);
+       data.mode = S_IFDIR | mode;
+       data.id = DIRECTORY_FILE_PLUGIN_ID;
+       return create_vfs_object(parent, dentry, &data);
+}
+
+/**
+ * reiser4_mknod_common - mknod of inode operations
+ * @parent: inode of parent directory
+ * @dentry: dentry of object to be created
+ * @mode: the permissions to use and file type
+ * @rdev: minor and major of new device file
+ *
+ * This is common implementation of vfs's mknod method of struct
+ * inode_operations.
+ * Creates object using file plugin SPECIAL_FILE_PLUGIN_ID.
+ */
+int reiser4_mknod_common(struct inode *parent, struct dentry *dentry,
+                        int mode, dev_t rdev)
+{
+       reiser4_object_create_data data;
+
+       memset(&data, 0, sizeof data);
+       data.mode = mode;
+       data.rdev = rdev;
+       data.id = SPECIAL_FILE_PLUGIN_ID;
+       return create_vfs_object(parent, dentry, &data);
+}
+
+/*
+ * implementation of vfs's rename method of struct inode_operations for typical
+ * directory is in inode_ops_rename.c
+ */
+
+/**
+ * reiser4_follow_link_common - follow_link of inode operations
+ * @dentry: dentry of symlink
+ * @data:
+ *
+ * This is common implementation of vfs's followlink method of struct
+ * inode_operations.
+ * Assumes that inode's i_private points to the content of symbolic link.
+ */
+void *reiser4_follow_link_common(struct dentry *dentry, struct nameidata *nd)
+{
+       assert("vs-851", S_ISLNK(dentry->d_inode->i_mode));
+
+       if (!dentry->d_inode->i_private
+           || !reiser4_inode_get_flag(dentry->d_inode,
+                                      REISER4_GENERIC_PTR_USED))
+               return ERR_PTR(RETERR(-EINVAL));
+       nd_set_link(nd, dentry->d_inode->i_private);
+       return NULL;
+}
+
+/**
+ * reiser4_permission_common - permission of inode operations
+ * @inode: inode to check permissions for
+ * @mask: mode bits to check permissions for
+ * @nameidata:
+ *
+ * Uses generic function to check for rwx permissions.
+ */
+int reiser4_permission_common(struct inode *inode, int mask,
+                             struct nameidata *nameidata)
+{
+       return generic_permission(inode, mask, NULL);
+}
+
+static int setattr_reserve(reiser4_tree *);
+
+/* this is common implementation of vfs's setattr method of struct
+   inode_operations
+*/
+int reiser4_setattr_common(struct dentry *dentry, struct iattr *attr)
+{
+       reiser4_context *ctx;
+       struct inode *inode;
+       int result;
+
+       inode = dentry->d_inode;
+       result = inode_change_ok(inode, attr);
+       if (result)
+               return result;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       assert("nikita-3119", !(attr->ia_valid & ATTR_SIZE));
+
+       /*
+        * grab disk space and call standard inode_setattr().
+        */
+       result = setattr_reserve(reiser4_tree_by_inode(inode));
+       if (!result) {
+               if ((attr->ia_valid & ATTR_UID && attr->ia_uid != inode->i_uid)
+                   || (attr->ia_valid & ATTR_GID
+                       && attr->ia_gid != inode->i_gid)) {
+                       result = DQUOT_TRANSFER(inode, attr) ? -EDQUOT : 0;
+                       if (result) {
+                               context_set_commit_async(ctx);
+                               reiser4_exit_context(ctx);
+                               return result;
+                       }
+               }
+               result = inode_setattr(inode, attr);
+               if (!result)
+                       reiser4_update_sd(inode);
+       }
+
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* this is common implementation of vfs's getattr method of struct
+   inode_operations
+*/
+int reiser4_getattr_common(struct vfsmount *mnt UNUSED_ARG,
+                          struct dentry *dentry, struct kstat *stat)
+{
+       struct inode *obj;
+
+       assert("nikita-2298", dentry != NULL);
+       assert("nikita-2299", stat != NULL);
+       assert("nikita-2300", dentry->d_inode != NULL);
+
+       obj = dentry->d_inode;
+
+       stat->dev = obj->i_sb->s_dev;
+       stat->ino = oid_to_uino(get_inode_oid(obj));
+       stat->mode = obj->i_mode;
+       /* don't confuse userland with huge nlink. This is not entirely
+        * correct, because nlink_t is not necessary 16 bit signed. */
+       stat->nlink = min(obj->i_nlink, (typeof(obj->i_nlink)) 0x7fff);
+       stat->uid = obj->i_uid;
+       stat->gid = obj->i_gid;
+       stat->rdev = obj->i_rdev;
+       stat->atime = obj->i_atime;
+       stat->mtime = obj->i_mtime;
+       stat->ctime = obj->i_ctime;
+       stat->size = obj->i_size;
+       stat->blocks =
+           (inode_get_bytes(obj) + VFS_BLKSIZE - 1) >> VFS_BLKSIZE_BITS;
+       /* "preferred" blocksize for efficient file system I/O */
+       stat->blksize = get_super_private(obj->i_sb)->optimal_io_size;
+
+       return 0;
+}
+
+/* Estimate the maximum amount of nodes which might be allocated or changed on
+   typical new object creation. Typical creation consists of calling create
+   method of file plugin, adding directory entry to parent and update parent
+   directory's stat data.
+*/
+static reiser4_block_nr estimate_create_vfs_object(struct inode *parent,       /* parent object */
+                                                  struct inode *object
+                                                  /* object */ )
+{
+       assert("vpf-309", parent != NULL);
+       assert("vpf-307", object != NULL);
+
+       return
+           /* object creation estimation */
+           inode_file_plugin(object)->estimate.create(object) +
+           /* stat data of parent directory estimation */
+           inode_file_plugin(parent)->estimate.update(parent) +
+           /* adding entry estimation */
+           inode_dir_plugin(parent)->estimate.add_entry(parent) +
+           /* to undo in the case of failure */
+           inode_dir_plugin(parent)->estimate.rem_entry(parent);
+}
+
+/* Create child in directory.
+
+   . get object's plugin
+   . get fresh inode
+   . initialize inode
+   . add object's stat-data
+   . initialize object's directory
+   . add entry to the parent
+   . instantiate dentry
+
+*/
+static int do_create_vfs_child(reiser4_object_create_data * data,      /* parameters of new
+                                                                          object */
+                              struct inode **retobj)
+{
+       int result;
+
+       struct dentry *dentry;  /* parent object */
+       struct inode *parent;   /* new name */
+
+       dir_plugin *par_dir;    /* directory plugin on the parent */
+       dir_plugin *obj_dir;    /* directory plugin on the new object */
+       file_plugin *obj_plug;  /* object plugin on the new object */
+       struct inode *object;   /* new object */
+       reiser4_block_nr reserve;
+
+       reiser4_dir_entry_desc entry;   /* new directory entry */
+
+       assert("nikita-1420", data != NULL);
+       parent = data->parent;
+       dentry = data->dentry;
+
+       assert("nikita-1418", parent != NULL);
+       assert("nikita-1419", dentry != NULL);
+
+       /* check, that name is acceptable for parent */
+       par_dir = inode_dir_plugin(parent);
+       if (par_dir->is_name_acceptable &&
+           !par_dir->is_name_acceptable(parent,
+                                        dentry->d_name.name,
+                                        (int)dentry->d_name.len))
+               return RETERR(-ENAMETOOLONG);
+
+       result = 0;
+       obj_plug = file_plugin_by_id((int)data->id);
+       if (obj_plug == NULL) {
+               warning("nikita-430", "Cannot find plugin %i", data->id);
+               return RETERR(-ENOENT);
+       }
+       object = new_inode(parent->i_sb);
+       if (object == NULL)
+               return RETERR(-ENOMEM);
+       /* we'll update i_nlink below */
+       object->i_nlink = 0;
+       /* new_inode() initializes i_ino to "arbitrary" value. Reset it to 0,
+        * to simplify error handling: if some error occurs before i_ino is
+        * initialized with oid, i_ino should already be set to some
+        * distinguished value. */
+       object->i_ino = 0;
+
+       /* So that on error iput will be called. */
+       *retobj = object;
+
+       if (DQUOT_ALLOC_INODE(object)) {
+               DQUOT_DROP(object);
+               object->i_flags |= S_NOQUOTA;
+               return RETERR(-EDQUOT);
+       }
+
+       memset(&entry, 0, sizeof entry);
+       entry.obj = object;
+
+       set_plugin(&reiser4_inode_data(object)->pset, PSET_FILE,
+                  file_plugin_to_plugin(obj_plug));
+       result = obj_plug->set_plug_in_inode(object, parent, data);
+       if (result) {
+               warning("nikita-431", "Cannot install plugin %i on %llx",
+                       data->id, (unsigned long long)get_inode_oid(object));
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return result;
+       }
+
+       /* reget plugin after installation */
+       obj_plug = inode_file_plugin(object);
+
+       if (obj_plug->create_object == NULL) {
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return RETERR(-EPERM);
+       }
+
+       /* if any of hash, tail, sd or permission plugins for newly created
+          object are not set yet set them here inheriting them from parent
+          directory
+        */
+       assert("nikita-2070", obj_plug->adjust_to_parent != NULL);
+       result = obj_plug->adjust_to_parent(object,
+                                           parent,
+                                           object->i_sb->s_root->d_inode);
+       if (result == 0)
+               result = finish_pset(object);
+       if (result != 0) {
+               warning("nikita-432", "Cannot inherit from %llx to %llx",
+                       (unsigned long long)get_inode_oid(parent),
+                       (unsigned long long)get_inode_oid(object));
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return result;
+       }
+
+       /* setup inode and file-operations for this inode */
+       setup_inode_ops(object, data);
+
+       /* call file plugin's method to initialize plugin specific part of
+        * inode */
+       if (obj_plug->init_inode_data)
+               obj_plug->init_inode_data(object, data, 1 /*create */ );
+
+       /* obtain directory plugin (if any) for new object. */
+       obj_dir = inode_dir_plugin(object);
+       if (obj_dir != NULL && obj_dir->init == NULL) {
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return RETERR(-EPERM);
+       }
+
+       reiser4_inode_data(object)->locality_id = get_inode_oid(parent);
+
+       reserve = estimate_create_vfs_object(parent, object);
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT)) {
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return RETERR(-ENOSPC);
+       }
+
+       /* mark inode `immutable'. We disable changes to the file being
+          created until valid directory entry for it is inserted. Otherwise,
+          if file were expanded and insertion of directory entry fails, we
+          have to remove file, but we only alloted enough space in
+          transaction to remove _empty_ file. 3.x code used to remove stat
+          data in different transaction thus possibly leaking disk space on
+          crash. This all only matters if it's possible to access file
+          without name, for example, by inode number
+        */
+       reiser4_inode_set_flag(object, REISER4_IMMUTABLE);
+
+       /* create empty object, this includes allocation of new objectid. For
+          directories this implies creation of dot and dotdot  */
+       assert("nikita-2265", reiser4_inode_get_flag(object, REISER4_NO_SD));
+
+       /* mark inode as `loaded'. From this point onward
+          reiser4_delete_inode() will try to remove its stat-data. */
+       reiser4_inode_set_flag(object, REISER4_LOADED);
+
+       result = obj_plug->create_object(object, parent, data);
+       if (result != 0) {
+               reiser4_inode_clr_flag(object, REISER4_IMMUTABLE);
+               if (result != -ENAMETOOLONG && result != -ENOMEM)
+                       warning("nikita-2219",
+                               "Failed to create sd for %llu",
+                               (unsigned long long)get_inode_oid(object));
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               return result;
+       }
+
+       if (obj_dir != NULL)
+               result = obj_dir->init(object, parent, data);
+       if (result == 0) {
+               assert("nikita-434", !reiser4_inode_get_flag(object,
+                                                            REISER4_NO_SD));
+               /* insert inode into VFS hash table */
+               insert_inode_hash(object);
+               /* create entry */
+               result = par_dir->add_entry(parent, dentry, data, &entry);
+               if (result == 0) {
+                       result = reiser4_add_nlink(object, parent, 0);
+                       /* If O_CREAT is set and the file did not previously
+                          exist, upon successful completion, open() shall
+                          mark for update the st_atime, st_ctime, and
+                          st_mtime fields of the file and the st_ctime and
+                          st_mtime fields of the parent directory. --SUS
+                        */
+                       /* @object times are already updated by
+                          reiser4_add_nlink() */
+                       if (result == 0)
+                               reiser4_update_dir(parent);
+                       if (result != 0)
+                               /* cleanup failure to add nlink */
+                               par_dir->rem_entry(parent, dentry, &entry);
+               }
+               if (result != 0)
+                       /* cleanup failure to add entry */
+                       obj_plug->detach(object, parent);
+       } else if (result != -ENOMEM)
+               warning("nikita-2219", "Failed to initialize dir for %llu: %i",
+                       (unsigned long long)get_inode_oid(object), result);
+
+       /*
+        * update stat-data, committing all pending modifications to the inode
+        * fields.
+        */
+       reiser4_update_sd(object);
+       if (result != 0) {
+               DQUOT_FREE_INODE(object);
+               object->i_flags |= S_NOQUOTA;
+               /* if everything was ok (result == 0), parent stat-data is
+                * already updated above (update_parent_dir()) */
+               reiser4_update_sd(parent);
+               /* failure to create entry, remove object */
+               obj_plug->delete_object(object);
+       }
+
+       /* file has name now, clear immutable flag */
+       reiser4_inode_clr_flag(object, REISER4_IMMUTABLE);
+
+       /* on error, iput() will call ->delete_inode(). We should keep track
+          of the existence of stat-data for this inode and avoid attempt to
+          remove it in reiser4_delete_inode(). This is accomplished through
+          REISER4_NO_SD bit in inode.u.reiser4_i.plugin.flags
+        */
+       return result;
+}
+
+/* this is helper for common implementations of reiser4_mkdir, reiser4_create,
+   reiser4_mknod and reiser4_symlink
+*/
+static int
+create_vfs_object(struct inode *parent,
+                 struct dentry *dentry, reiser4_object_create_data * data)
+{
+       reiser4_context *ctx;
+       int result;
+       struct inode *child;
+
+       ctx = reiser4_init_context(parent->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+       context_set_commit_async(ctx);
+
+       data->parent = parent;
+       data->dentry = dentry;
+       child = NULL;
+       result = do_create_vfs_child(data, &child);
+       if (unlikely(result != 0)) {
+               if (child != NULL) {
+                       reiser4_make_bad_inode(child);
+                       iput(child);
+               }
+       } else
+               d_instantiate(dentry, child);
+
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+/* helper for link_common. Estimate disk space necessary to add a link
+   from @parent to @object
+*/
+static reiser4_block_nr common_estimate_link(struct inode *parent,     /* parent directory */
+                                            struct inode *object
+                                            /* object to which new link is being cerated */
+                                            )
+{
+       reiser4_block_nr res = 0;
+       file_plugin *fplug;
+       dir_plugin *dplug;
+
+       assert("vpf-317", object != NULL);
+       assert("vpf-318", parent != NULL);
+
+       fplug = inode_file_plugin(object);
+       dplug = inode_dir_plugin(parent);
+       /* VS-FIXME-HANS: why do we do fplug->estimate.update(object) twice instead of multiplying by 2? */
+       /* reiser4_add_nlink(object) */
+       res += fplug->estimate.update(object);
+       /* add_entry(parent) */
+       res += dplug->estimate.add_entry(parent);
+       /* reiser4_del_nlink(object) */
+       res += fplug->estimate.update(object);
+       /* update_dir(parent) */
+       res += inode_file_plugin(parent)->estimate.update(parent);
+       /* safe-link */
+       res += estimate_one_item_removal(reiser4_tree_by_inode(object));
+
+       return res;
+}
+
+/* Estimate disk space necessary to remove a link between @parent and
+   @object.
+*/
+static reiser4_block_nr estimate_unlink(struct inode *parent,  /* parent directory */
+                                       struct inode *object
+                                       /* object to which new link is being cerated */
+                                       )
+{
+       reiser4_block_nr res = 0;
+       file_plugin *fplug;
+       dir_plugin *dplug;
+
+       assert("vpf-317", object != NULL);
+       assert("vpf-318", parent != NULL);
+
+       fplug = inode_file_plugin(object);
+       dplug = inode_dir_plugin(parent);
+
+       /* rem_entry(parent) */
+       res += dplug->estimate.rem_entry(parent);
+       /* reiser4_del_nlink(object) */
+       res += fplug->estimate.update(object);
+       /* update_dir(parent) */
+       res += inode_file_plugin(parent)->estimate.update(parent);
+       /* fplug->unlink */
+       res += fplug->estimate.unlink(object, parent);
+       /* safe-link */
+       res += estimate_one_insert_item(reiser4_tree_by_inode(object));
+
+       return res;
+}
+
+/* helper for reiser4_unlink_common. Estimate and grab space for unlink. */
+static int unlink_check_and_grab(struct inode *parent, struct dentry *victim)
+{
+       file_plugin *fplug;
+       struct inode *child;
+       int result;
+
+       result = 0;
+       child = victim->d_inode;
+       fplug = inode_file_plugin(child);
+
+       /* check for race with create_object() */
+       if (reiser4_inode_get_flag(child, REISER4_IMMUTABLE))
+               return RETERR(-E_REPEAT);
+       /* object being deleted should have stat data */
+       assert("vs-949", !reiser4_inode_get_flag(child, REISER4_NO_SD));
+
+       /* ask object plugin */
+       if (fplug->can_rem_link != NULL && !fplug->can_rem_link(child))
+               return RETERR(-ENOTEMPTY);
+
+       result = (int)estimate_unlink(parent, child);
+       if (result < 0)
+               return result;
+
+       return reiser4_grab_reserved(child->i_sb, result, BA_CAN_COMMIT);
+}
+
+/* helper for reiser4_setattr_common */
+static int setattr_reserve(reiser4_tree * tree)
+{
+       assert("vs-1096", is_grab_enabled(get_current_context()));
+       return reiser4_grab_space(estimate_one_insert_into_item(tree),
+                                 BA_CAN_COMMIT);
+}
+
+/* helper function. Standards require that for many file-system operations
+   on success ctime and mtime of parent directory is to be updated. */
+int reiser4_update_dir(struct inode *dir)
+{
+       assert("nikita-2525", dir != NULL);
+
+       dir->i_ctime = dir->i_mtime = CURRENT_TIME;
+       return reiser4_update_sd(dir);
+}
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/inode_ops_rename.c linux-2.6.20/fs/reiser4/plugin/inode_ops_rename.c
--- linux-2.6.20.orig/fs/reiser4/plugin/inode_ops_rename.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/inode_ops_rename.c   2007-05-06 14:50:43.795005721 +0400
@@ -0,0 +1,914 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "../inode.h"
+#include "../safe_link.h"
+
+static const char *possible_leak = "Possible disk space leak.";
+
+/* re-bind existing name at @from_coord in @from_dir to point to @to_inode.
+
+   Helper function called from hashed_rename() */
+static int replace_name(struct inode *to_inode,        /* inode where @from_coord is
+                                                * to be re-targeted at */
+                       struct inode *from_dir, /* directory where @from_coord
+                                                * lives */
+                       struct inode *from_inode,       /* inode @from_coord
+                                                        * originally point to */
+                       coord_t * from_coord,   /* where directory entry is in
+                                                * the tree */
+                       lock_handle * from_lh /* lock handle on @from_coord */ )
+{
+       item_plugin *from_item;
+       int result;
+       znode *node;
+
+       coord_clear_iplug(from_coord);
+       node = from_coord->node;
+       result = zload(node);
+       if (result != 0)
+               return result;
+       from_item = item_plugin_by_coord(from_coord);
+       if (plugin_of_group(item_plugin_by_coord(from_coord),
+                           DIR_ENTRY_ITEM_TYPE))
+       {
+               reiser4_key to_key;
+
+               build_sd_key(to_inode, &to_key);
+
+               /* everything is found and prepared to change directory entry
+                  at @from_coord to point to @to_inode.
+
+                  @to_inode is just about to get new name, so bump its link
+                  counter.
+
+                */
+               result = reiser4_add_nlink(to_inode, from_dir, 0);
+               if (result != 0) {
+                       /* Don't issue warning: this may be plain -EMLINK */
+                       zrelse(node);
+                       return result;
+               }
+
+               result =
+                   from_item->s.dir.update_key(from_coord, &to_key, from_lh);
+               if (result != 0) {
+                       reiser4_del_nlink(to_inode, from_dir, 0);
+                       zrelse(node);
+                       return result;
+               }
+
+               /* @from_inode just lost its name, he-he.
+
+                  If @from_inode was directory, it contained dotdot pointing
+                  to @from_dir. @from_dir i_nlink will be decreased when
+                  iput() will be called on @from_inode.
+
+                  If file-system is not ADG (hard-links are
+                  supported on directories), iput(from_inode) will not remove
+                  @from_inode, and thus above is incorrect, but hard-links on
+                  directories are problematic in many other respects.
+                */
+               result = reiser4_del_nlink(from_inode, from_dir, 0);
+               if (result != 0) {
+                       warning("nikita-2330",
+                               "Cannot remove link from source: %i. %s",
+                               result, possible_leak);
+               }
+               /* Has to return success, because entry is already
+                * modified. */
+               result = 0;
+
+               /* NOTE-NIKITA consider calling plugin method in stead of
+                  accessing inode fields directly. */
+               from_dir->i_mtime = CURRENT_TIME;
+       } else {
+               warning("nikita-2326", "Unexpected item type");
+               result = RETERR(-EIO);
+       }
+       zrelse(node);
+       return result;
+}
+
+/* add new entry pointing to @inode into @dir at @coord, locked by @lh
+
+   Helper function used by hashed_rename(). */
+static int add_name(struct inode *inode,       /* inode where @coord is to be
+                                                * re-targeted at */
+                   struct inode *dir,  /* directory where @coord lives */
+                   struct dentry *name,        /* new name */
+                   coord_t * coord,    /* where directory entry is in the tree */
+                   lock_handle * lh,   /* lock handle on @coord */
+                   int is_dir /* true, if @inode is directory */ )
+{
+       int result;
+       reiser4_dir_entry_desc entry;
+
+       assert("nikita-2333", lh->node == coord->node);
+       assert("nikita-2334", is_dir == S_ISDIR(inode->i_mode));
+
+       memset(&entry, 0, sizeof entry);
+       entry.obj = inode;
+       /* build key of directory entry description */
+       inode_dir_plugin(dir)->build_entry_key(dir, &name->d_name, &entry.key);
+
+       /* ext2 does this in different order: first inserts new entry,
+          then increases directory nlink. We don't want do this,
+          because reiser4_add_nlink() calls ->add_link() plugin
+          method that can fail for whatever reason, leaving as with
+          cleanup problems.
+        */
+       /* @inode is getting new name */
+       reiser4_add_nlink(inode, dir, 0);
+       /* create @new_name in @new_dir pointing to
+          @old_inode */
+       result = WITH_COORD(coord,
+                           inode_dir_item_plugin(dir)->s.dir.add_entry(dir,
+                                                                       coord,
+                                                                       lh,
+                                                                       name,
+                                                                       &entry));
+       if (result != 0) {
+               int result2;
+               result2 = reiser4_del_nlink(inode, dir, 0);
+               if (result2 != 0) {
+                       warning("nikita-2327",
+                               "Cannot drop link on %lli %i. %s",
+                               (unsigned long long)get_inode_oid(inode),
+                               result2, possible_leak);
+               }
+       } else
+               INODE_INC_FIELD(dir, i_size);
+       return result;
+}
+
+static reiser4_block_nr estimate_rename(struct inode *old_dir, /* directory where @old is located */
+                                       struct dentry *old_name,        /* old name */
+                                       struct inode *new_dir,  /* directory where @new is located */
+                                       struct dentry *new_name /* new name */ )
+{
+       reiser4_block_nr res1, res2;
+       dir_plugin *p_parent_old, *p_parent_new;
+       file_plugin *p_child_old, *p_child_new;
+
+       assert("vpf-311", old_dir != NULL);
+       assert("vpf-312", new_dir != NULL);
+       assert("vpf-313", old_name != NULL);
+       assert("vpf-314", new_name != NULL);
+
+       p_parent_old = inode_dir_plugin(old_dir);
+       p_parent_new = inode_dir_plugin(new_dir);
+       p_child_old = inode_file_plugin(old_name->d_inode);
+       if (new_name->d_inode)
+               p_child_new = inode_file_plugin(new_name->d_inode);
+       else
+               p_child_new = NULL;
+
+       /* find_entry - can insert one leaf. */
+       res1 = res2 = 1;
+
+       /* replace_name */
+       {
+               /* reiser4_add_nlink(p_child_old) and reiser4_del_nlink(p_child_old) */
+               res1 += 2 * p_child_old->estimate.update(old_name->d_inode);
+               /* update key */
+               res1 += 1;
+               /* reiser4_del_nlink(p_child_new) */
+               if (p_child_new)
+                       res1 += p_child_new->estimate.update(new_name->d_inode);
+       }
+
+       /* else add_name */
+       {
+               /* reiser4_add_nlink(p_parent_new) and reiser4_del_nlink(p_parent_new) */
+               res2 +=
+                   2 * inode_file_plugin(new_dir)->estimate.update(new_dir);
+               /* reiser4_add_nlink(p_parent_old) */
+               res2 += p_child_old->estimate.update(old_name->d_inode);
+               /* add_entry(p_parent_new) */
+               res2 += p_parent_new->estimate.add_entry(new_dir);
+               /* reiser4_del_nlink(p_parent_old) */
+               res2 += p_child_old->estimate.update(old_name->d_inode);
+       }
+
+       res1 = res1 < res2 ? res2 : res1;
+
+       /* reiser4_write_sd(p_parent_new) */
+       res1 += inode_file_plugin(new_dir)->estimate.update(new_dir);
+
+       /* reiser4_write_sd(p_child_new) */
+       if (p_child_new)
+               res1 += p_child_new->estimate.update(new_name->d_inode);
+
+       /* hashed_rem_entry(p_parent_old) */
+       res1 += p_parent_old->estimate.rem_entry(old_dir);
+
+       /* reiser4_del_nlink(p_child_old) */
+       res1 += p_child_old->estimate.update(old_name->d_inode);
+
+       /* replace_name */
+       {
+               /* reiser4_add_nlink(p_parent_dir_new) */
+               res1 += inode_file_plugin(new_dir)->estimate.update(new_dir);
+               /* update_key */
+               res1 += 1;
+               /* reiser4_del_nlink(p_parent_new) */
+               res1 += inode_file_plugin(new_dir)->estimate.update(new_dir);
+               /* reiser4_del_nlink(p_parent_old) */
+               res1 += inode_file_plugin(old_dir)->estimate.update(old_dir);
+       }
+
+       /* reiser4_write_sd(p_parent_old) */
+       res1 += inode_file_plugin(old_dir)->estimate.update(old_dir);
+
+       /* reiser4_write_sd(p_child_old) */
+       res1 += p_child_old->estimate.update(old_name->d_inode);
+
+       return res1;
+}
+
+static int hashed_rename_estimate_and_grab(struct inode *old_dir,      /* directory where @old is located */
+                                          struct dentry *old_name,     /* old name */
+                                          struct inode *new_dir,       /* directory where @new is located */
+                                          struct dentry *new_name
+                                          /* new name */ )
+{
+       reiser4_block_nr reserve;
+
+       reserve = estimate_rename(old_dir, old_name, new_dir, new_name);
+
+       if (reiser4_grab_space(reserve, BA_CAN_COMMIT))
+               return RETERR(-ENOSPC);
+
+       return 0;
+}
+
+/* check whether @old_inode and @new_inode can be moved within file system
+ * tree. This singles out attempts to rename pseudo-files, for example. */
+static int can_rename(struct inode *old_dir, struct inode *old_inode,
+                     struct inode *new_dir, struct inode *new_inode)
+{
+       file_plugin *fplug;
+       dir_plugin *dplug;
+
+       assert("nikita-3370", old_inode != NULL);
+
+       dplug = inode_dir_plugin(new_dir);
+       fplug = inode_file_plugin(old_inode);
+
+       if (dplug == NULL)
+               return RETERR(-ENOTDIR);
+       else if (new_dir->i_op->create == NULL)
+               return RETERR(-EPERM);
+       else if (!fplug->can_add_link(old_inode))
+               return RETERR(-EMLINK);
+       else if (new_inode != NULL) {
+               fplug = inode_file_plugin(new_inode);
+               if (fplug->can_rem_link != NULL &&
+                   !fplug->can_rem_link(new_inode))
+                       return RETERR(-EBUSY);
+       }
+       return 0;
+}
+
+int reiser4_find_entry(struct inode *, struct dentry *, lock_handle *,
+              znode_lock_mode, reiser4_dir_entry_desc *);
+int reiser4_update_dir(struct inode *);
+
+/* this is common implementation of vfs's rename method of struct
+   inode_operations
+   See comments in the body.
+
+   It is arguable that this function can be made generic so, that it
+   will be applicable to any kind of directory plugin that deals with
+   directories composed out of directory entries. The only obstacle
+   here is that we don't have any data-type to represent directory
+   entry. This should be re-considered when more than one different
+   directory plugin will be implemented.
+*/
+int reiser4_rename_common(struct inode *old_dir /* directory where @old
+                                                * is located */ ,
+                         struct dentry *old_name /* old name */ ,
+                         struct inode *new_dir /* directory where @new
+                                                * is located */ ,
+                         struct dentry *new_name /* new name */ )
+{
+       /* From `The Open Group Base Specifications Issue 6'
+
+          If either the old or new argument names a symbolic link, rename()
+          shall operate on the symbolic link itself, and shall not resolve
+          the last component of the argument. If the old argument and the new
+          argument resolve to the same existing file, rename() shall return
+          successfully and perform no other action.
+
+          [this is done by VFS: vfs_rename()]
+
+          If the old argument points to the pathname of a file that is not a
+          directory, the new argument shall not point to the pathname of a
+          directory.
+
+          [checked by VFS: vfs_rename->may_delete()]
+
+          If the link named by the new argument exists, it shall
+          be removed and old renamed to new. In this case, a link named new
+          shall remain visible to other processes throughout the renaming
+          operation and refer either to the file referred to by new or old
+          before the operation began.
+
+          [we should assure this]
+
+          Write access permission is required for
+          both the directory containing old and the directory containing new.
+
+          [checked by VFS: vfs_rename->may_delete(), may_create()]
+
+          If the old argument points to the pathname of a directory, the new
+          argument shall not point to the pathname of a file that is not a
+          directory.
+
+          [checked by VFS: vfs_rename->may_delete()]
+
+          If the directory named by the new argument exists, it
+          shall be removed and old renamed to new. In this case, a link named
+          new shall exist throughout the renaming operation and shall refer
+          either to the directory referred to by new or old before the
+          operation began.
+
+          [we should assure this]
+
+          If new names an existing directory, it shall be
+          required to be an empty directory.
+
+          [we should check this]
+
+          If the old argument points to a pathname of a symbolic link, the
+          symbolic link shall be renamed. If the new argument points to a
+          pathname of a symbolic link, the symbolic link shall be removed.
+
+          The new pathname shall not contain a path prefix that names
+          old. Write access permission is required for the directory
+          containing old and the directory containing new. If the old
+          argument points to the pathname of a directory, write access
+          permission may be required for the directory named by old, and, if
+          it exists, the directory named by new.
+
+          [checked by VFS: vfs_rename(), vfs_rename_dir()]
+
+          If the link named by the new argument exists and the file's link
+          count becomes 0 when it is removed and no process has the file
+          open, the space occupied by the file shall be freed and the file
+          shall no longer be accessible. If one or more processes have the
+          file open when the last link is removed, the link shall be removed
+          before rename() returns, but the removal of the file contents shall
+          be postponed until all references to the file are closed.
+
+          [iput() handles this, but we can do this manually, a la
+          reiser4_unlink()]
+
+          Upon successful completion, rename() shall mark for update the
+          st_ctime and st_mtime fields of the parent directory of each file.
+
+          [N/A]
+
+        */
+       reiser4_context *ctx;
+       int result;
+       int is_dir;             /* is @old_name directory */
+
+       struct inode *old_inode;
+       struct inode *new_inode;
+       coord_t *new_coord;
+
+       reiser4_dentry_fsdata *new_fsdata;
+       dir_plugin *dplug;
+       file_plugin *fplug;
+
+       reiser4_dir_entry_desc *old_entry, *new_entry, *dotdot_entry;
+       lock_handle *new_lh, *dotdot_lh;
+       struct dentry *dotdot_name;
+       reiser4_dentry_fsdata *dataonstack;
+
+       ctx = reiser4_init_context(old_dir->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       old_entry = kmalloc(3 * sizeof(*old_entry) + 2 * sizeof(*new_lh) +
+                           sizeof(*dotdot_name) + sizeof(*dataonstack),
+                           reiser4_ctx_gfp_mask_get());
+       if (old_entry == NULL) {
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return RETERR(-ENOMEM);
+       }
+       memset(old_entry, 0, 3 * sizeof(*old_entry) + 2 * sizeof(*new_lh) +
+              sizeof(*dotdot_name) + sizeof(*dataonstack));
+
+       new_entry = old_entry + 1;
+       dotdot_entry = old_entry + 2;
+       new_lh = (lock_handle *)(old_entry + 3);
+       dotdot_lh = new_lh + 1;
+       dotdot_name = (struct dentry *)(new_lh + 2);
+       dataonstack = (reiser4_dentry_fsdata *)(dotdot_name + 1);
+
+       assert("nikita-2318", old_dir != NULL);
+       assert("nikita-2319", new_dir != NULL);
+       assert("nikita-2320", old_name != NULL);
+       assert("nikita-2321", new_name != NULL);
+
+       old_inode = old_name->d_inode;
+       new_inode = new_name->d_inode;
+
+       dplug = inode_dir_plugin(old_dir);
+       fplug = NULL;
+
+       new_fsdata = reiser4_get_dentry_fsdata(new_name);
+       if (IS_ERR(new_fsdata)) {
+               kfree(old_entry);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return PTR_ERR(new_fsdata);
+       }
+
+       new_coord = &new_fsdata->dec.entry_coord;
+       coord_clear_iplug(new_coord);
+
+       is_dir = S_ISDIR(old_inode->i_mode);
+
+       assert("nikita-3461", old_inode->i_nlink >= 1 + !!is_dir);
+
+       /* if target is existing directory and it's not empty---return error.
+
+          This check is done specifically, because is_dir_empty() requires
+          tree traversal and have to be done before locks are taken.
+        */
+       if (is_dir && new_inode != NULL && is_dir_empty(new_inode) != 0) {
+               kfree(old_entry);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return RETERR(-ENOTEMPTY);
+       }
+
+       result = can_rename(old_dir, old_inode, new_dir, new_inode);
+       if (result != 0) {
+               kfree(old_entry);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       result = hashed_rename_estimate_and_grab(old_dir, old_name,
+                                                new_dir, new_name);
+       if (result != 0) {
+               kfree(old_entry);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       init_lh(new_lh);
+
+       /* find entry for @new_name */
+       result = reiser4_find_entry(new_dir, new_name, new_lh, ZNODE_WRITE_LOCK,
+                                   new_entry);
+
+       if (IS_CBKERR(result)) {
+               done_lh(new_lh);
+               kfree(old_entry);
+               context_set_commit_async(ctx);
+               reiser4_exit_context(ctx);
+               return result;
+       }
+
+       reiser4_seal_done(&new_fsdata->dec.entry_seal);
+
+       /* add or replace name for @old_inode as @new_name */
+       if (new_inode != NULL) {
+               /* target (@new_name) exists. */
+               /* Not clear what to do with objects that are
+                  both directories and files at the same time. */
+               if (result == CBK_COORD_FOUND) {
+                       result = replace_name(old_inode,
+                                             new_dir,
+                                             new_inode, new_coord, new_lh);
+                       if (result == 0)
+                               fplug = inode_file_plugin(new_inode);
+               } else if (result == CBK_COORD_NOTFOUND) {
+                       /* VFS told us that @new_name is bound to existing
+                          inode, but we failed to find directory entry. */
+                       warning("nikita-2324", "Target not found");
+                       result = RETERR(-ENOENT);
+               }
+       } else {
+               /* target (@new_name) doesn't exists. */
+               if (result == CBK_COORD_NOTFOUND)
+                       result = add_name(old_inode,
+                                         new_dir,
+                                         new_name, new_coord, new_lh, is_dir);
+               else if (result == CBK_COORD_FOUND) {
+                       /* VFS told us that @new_name is "negative" dentry,
+                          but we found directory entry. */
+                       warning("nikita-2331", "Target found unexpectedly");
+                       result = RETERR(-EIO);
+               }
+       }
+
+       assert("nikita-3462", ergo(result == 0,
+                                  old_inode->i_nlink >= 2 + !!is_dir));
+
+       /* We are done with all modifications to the @new_dir, release lock on
+          node. */
+       done_lh(new_lh);
+
+       if (fplug != NULL) {
+               /* detach @new_inode from name-space */
+               result = fplug->detach(new_inode, new_dir);
+               if (result != 0)
+                       warning("nikita-2330", "Cannot detach %lli: %i. %s",
+                               (unsigned long long)get_inode_oid(new_inode),
+                               result, possible_leak);
+       }
+
+       if (new_inode != NULL)
+               reiser4_update_sd(new_inode);
+
+       if (result == 0) {
+               old_entry->obj = old_inode;
+
+               dplug->build_entry_key(old_dir,
+                                      &old_name->d_name, &old_entry->key);
+
+               /* At this stage new name was introduced for
+                  @old_inode. @old_inode, @new_dir, and @new_inode i_nlink
+                  counters were updated.
+
+                  We want to remove @old_name now. If @old_inode wasn't
+                  directory this is simple.
+                */
+               result = dplug->rem_entry(old_dir, old_name, old_entry);
+               if (result != 0 && result != -ENOMEM) {
+                       warning("nikita-2335",
+                               "Cannot remove old name: %i", result);
+               } else {
+                       result = reiser4_del_nlink(old_inode, old_dir, 0);
+                       if (result != 0 && result != -ENOMEM) {
+                               warning("nikita-2337",
+                                       "Cannot drop link on old: %i", result);
+                       }
+               }
+
+               if (result == 0 && is_dir) {
+                       /* @old_inode is directory. We also have to update
+                          dotdot entry. */
+                       coord_t *dotdot_coord;
+
+                       memset(dataonstack, 0, sizeof dataonstack);
+                       memset(dotdot_entry, 0, sizeof dotdot_entry);
+                       dotdot_entry->obj = old_dir;
+                       memset(dotdot_name, 0, sizeof dotdot_name);
+                       dotdot_name->d_name.name = "..";
+                       dotdot_name->d_name.len = 2;
+                       /*
+                        * allocate ->d_fsdata on the stack to avoid using
+                        * reiser4_get_dentry_fsdata(). Locking is not needed,
+                        * because dentry is private to the current thread.
+                        */
+                       dotdot_name->d_fsdata = dataonstack;
+                       init_lh(dotdot_lh);
+
+                       dotdot_coord = &dataonstack->dec.entry_coord;
+                       coord_clear_iplug(dotdot_coord);
+
+                       result = reiser4_find_entry(old_inode, dotdot_name,
+                                                   dotdot_lh, ZNODE_WRITE_LOCK,
+                                                   dotdot_entry);
+                       if (result == 0) {
+                               /* replace_name() decreases i_nlink on
+                                * @old_dir */
+                               result = replace_name(new_dir,
+                                                     old_inode,
+                                                     old_dir,
+                                                     dotdot_coord, dotdot_lh);
+                       } else
+                               result = RETERR(-EIO);
+                       done_lh(dotdot_lh);
+               }
+       }
+       reiser4_update_dir(new_dir);
+       reiser4_update_dir(old_dir);
+       reiser4_update_sd(old_inode);
+       if (result == 0) {
+               file_plugin *fplug;
+
+               if (new_inode != NULL) {
+                       /* add safe-link for target file (in case we removed
+                        * last reference to the poor fellow */
+                       fplug = inode_file_plugin(new_inode);
+                       if (new_inode->i_nlink == 0)
+                               result = safe_link_add(new_inode, SAFE_UNLINK);
+               }
+       }
+       kfree(old_entry);
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+
+#if 0
+int reiser4_rename_common(struct inode *old_dir /* directory where @old
+                                                * is located */ ,
+                         struct dentry *old_name /* old name */ ,
+                         struct inode *new_dir /* directory where @new
+                                                * is located */ ,
+                         struct dentry *new_name /* new name */ )
+{
+       /* From `The Open Group Base Specifications Issue 6'
+
+          If either the old or new argument names a symbolic link, rename()
+          shall operate on the symbolic link itself, and shall not resolve
+          the last component of the argument. If the old argument and the new
+          argument resolve to the same existing file, rename() shall return
+          successfully and perform no other action.
+
+          [this is done by VFS: vfs_rename()]
+
+          If the old argument points to the pathname of a file that is not a
+          directory, the new argument shall not point to the pathname of a
+          directory.
+
+          [checked by VFS: vfs_rename->may_delete()]
+
+          If the link named by the new argument exists, it shall
+          be removed and old renamed to new. In this case, a link named new
+          shall remain visible to other processes throughout the renaming
+          operation and refer either to the file referred to by new or old
+          before the operation began.
+
+          [we should assure this]
+
+          Write access permission is required for
+          both the directory containing old and the directory containing new.
+
+          [checked by VFS: vfs_rename->may_delete(), may_create()]
+
+          If the old argument points to the pathname of a directory, the new
+          argument shall not point to the pathname of a file that is not a
+          directory.
+
+          [checked by VFS: vfs_rename->may_delete()]
+
+          If the directory named by the new argument exists, it
+          shall be removed and old renamed to new. In this case, a link named
+          new shall exist throughout the renaming operation and shall refer
+          either to the directory referred to by new or old before the
+          operation began.
+
+          [we should assure this]
+
+          If new names an existing directory, it shall be
+          required to be an empty directory.
+
+          [we should check this]
+
+          If the old argument points to a pathname of a symbolic link, the
+          symbolic link shall be renamed. If the new argument points to a
+          pathname of a symbolic link, the symbolic link shall be removed.
+
+          The new pathname shall not contain a path prefix that names
+          old. Write access permission is required for the directory
+          containing old and the directory containing new. If the old
+          argument points to the pathname of a directory, write access
+          permission may be required for the directory named by old, and, if
+          it exists, the directory named by new.
+
+          [checked by VFS: vfs_rename(), vfs_rename_dir()]
+
+          If the link named by the new argument exists and the file's link
+          count becomes 0 when it is removed and no process has the file
+          open, the space occupied by the file shall be freed and the file
+          shall no longer be accessible. If one or more processes have the
+          file open when the last link is removed, the link shall be removed
+          before rename() returns, but the removal of the file contents shall
+          be postponed until all references to the file are closed.
+
+          [iput() handles this, but we can do this manually, a la
+          reiser4_unlink()]
+
+          Upon successful completion, rename() shall mark for update the
+          st_ctime and st_mtime fields of the parent directory of each file.
+
+          [N/A]
+
+        */
+       reiser4_context *ctx;
+       int result;
+       int is_dir;             /* is @old_name directory */
+       struct inode *old_inode;
+       struct inode *new_inode;
+       reiser4_dir_entry_desc old_entry;
+       reiser4_dir_entry_desc new_entry;
+       coord_t *new_coord;
+       reiser4_dentry_fsdata *new_fsdata;
+       lock_handle new_lh;
+       dir_plugin *dplug;
+       file_plugin *fplug;
+
+       ctx = reiser4_init_context(old_dir->i_sb);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       assert("nikita-2318", old_dir != NULL);
+       assert("nikita-2319", new_dir != NULL);
+       assert("nikita-2320", old_name != NULL);
+       assert("nikita-2321", new_name != NULL);
+
+       old_inode = old_name->d_inode;
+       new_inode = new_name->d_inode;
+
+       dplug = inode_dir_plugin(old_dir);
+       fplug = NULL;
+
+       new_fsdata = reiser4_get_dentry_fsdata(new_name);
+       if (IS_ERR(new_fsdata)) {
+               result = PTR_ERR(new_fsdata);
+               goto exit;
+       }
+
+       new_coord = &new_fsdata->dec.entry_coord;
+       coord_clear_iplug(new_coord);
+
+       is_dir = S_ISDIR(old_inode->i_mode);
+
+       assert("nikita-3461", old_inode->i_nlink >= 1 + !!is_dir);
+
+       /* if target is existing directory and it's not empty---return error.
+
+          This check is done specifically, because is_dir_empty() requires
+          tree traversal and have to be done before locks are taken.
+        */
+       if (is_dir && new_inode != NULL && is_dir_empty(new_inode) != 0)
+               return RETERR(-ENOTEMPTY);
+
+       result = can_rename(old_dir, old_inode, new_dir, new_inode);
+       if (result != 0)
+               goto exit;
+
+       result = hashed_rename_estimate_and_grab(old_dir, old_name,
+                                                new_dir, new_name);
+       if (result != 0)
+               goto exit;
+
+       init_lh(&new_lh);
+
+       /* find entry for @new_name */
+       result = reiser4_find_entry(new_dir, new_name, &new_lh,
+                                   ZNODE_WRITE_LOCK, &new_entry);
+
+       if (IS_CBKERR(result)) {
+               done_lh(&new_lh);
+               goto exit;
+       }
+
+       reiser4_seal_done(&new_fsdata->dec.entry_seal);
+
+       /* add or replace name for @old_inode as @new_name */
+       if (new_inode != NULL) {
+               /* target (@new_name) exists. */
+               /* Not clear what to do with objects that are
+                  both directories and files at the same time. */
+               if (result == CBK_COORD_FOUND) {
+                       result = replace_name(old_inode,
+                                             new_dir,
+                                             new_inode, new_coord, &new_lh);
+                       if (result == 0)
+                               fplug = inode_file_plugin(new_inode);
+               } else if (result == CBK_COORD_NOTFOUND) {
+                       /* VFS told us that @new_name is bound to existing
+                          inode, but we failed to find directory entry. */
+                       warning("nikita-2324", "Target not found");
+                       result = RETERR(-ENOENT);
+               }
+       } else {
+               /* target (@new_name) doesn't exists. */
+               if (result == CBK_COORD_NOTFOUND)
+                       result = add_name(old_inode,
+                                         new_dir,
+                                         new_name, new_coord, &new_lh, is_dir);
+               else if (result == CBK_COORD_FOUND) {
+                       /* VFS told us that @new_name is "negative" dentry,
+                          but we found directory entry. */
+                       warning("nikita-2331", "Target found unexpectedly");
+                       result = RETERR(-EIO);
+               }
+       }
+
+       assert("nikita-3462", ergo(result == 0,
+                                  old_inode->i_nlink >= 2 + !!is_dir));
+
+       /* We are done with all modifications to the @new_dir, release lock on
+          node. */
+       done_lh(&new_lh);
+
+       if (fplug != NULL) {
+               /* detach @new_inode from name-space */
+               result = fplug->detach(new_inode, new_dir);
+               if (result != 0)
+                       warning("nikita-2330", "Cannot detach %lli: %i. %s",
+                               (unsigned long long)get_inode_oid(new_inode),
+                               result, possible_leak);
+       }
+
+       if (new_inode != NULL)
+               reiser4_update_sd(new_inode);
+
+       if (result == 0) {
+               memset(&old_entry, 0, sizeof old_entry);
+               old_entry.obj = old_inode;
+
+               dplug->build_entry_key(old_dir,
+                                      &old_name->d_name, &old_entry.key);
+
+               /* At this stage new name was introduced for
+                  @old_inode. @old_inode, @new_dir, and @new_inode i_nlink
+                  counters were updated.
+
+                  We want to remove @old_name now. If @old_inode wasn't
+                  directory this is simple.
+                */
+               result = dplug->rem_entry(old_dir, old_name, &old_entry);
+               /*result = rem_entry_hashed(old_dir, old_name, &old_entry); */
+               if (result != 0 && result != -ENOMEM) {
+                       warning("nikita-2335",
+                               "Cannot remove old name: %i", result);
+               } else {
+                       result = reiser4_del_nlink(old_inode, old_dir, 0);
+                       if (result != 0 && result != -ENOMEM) {
+                               warning("nikita-2337",
+                                       "Cannot drop link on old: %i", result);
+                       }
+               }
+
+               if (result == 0 && is_dir) {
+                       /* @old_inode is directory. We also have to update
+                          dotdot entry. */
+                       coord_t *dotdot_coord;
+                       lock_handle dotdot_lh;
+                       struct dentry dotdot_name;
+                       reiser4_dir_entry_desc dotdot_entry;
+                       reiser4_dentry_fsdata dataonstack;
+                       reiser4_dentry_fsdata *fsdata;
+
+                       memset(&dataonstack, 0, sizeof dataonstack);
+                       memset(&dotdot_entry, 0, sizeof dotdot_entry);
+                       dotdot_entry.obj = old_dir;
+                       memset(&dotdot_name, 0, sizeof dotdot_name);
+                       dotdot_name.d_name.name = "..";
+                       dotdot_name.d_name.len = 2;
+                       /*
+                        * allocate ->d_fsdata on the stack to avoid using
+                        * reiser4_get_dentry_fsdata(). Locking is not needed,
+                        * because dentry is private to the current thread.
+                        */
+                       dotdot_name.d_fsdata = &dataonstack;
+                       init_lh(&dotdot_lh);
+
+                       fsdata = &dataonstack;
+                       dotdot_coord = &fsdata->dec.entry_coord;
+                       coord_clear_iplug(dotdot_coord);
+
+                       result = reiser4_find_entry(old_inode,
+                                                   &dotdot_name,
+                                                   &dotdot_lh,
+                                                   ZNODE_WRITE_LOCK,
+                                                   &dotdot_entry);
+                       if (result == 0) {
+                               /* replace_name() decreases i_nlink on
+                                * @old_dir */
+                               result = replace_name(new_dir,
+                                                     old_inode,
+                                                     old_dir,
+                                                     dotdot_coord, &dotdot_lh);
+                       } else
+                               result = RETERR(-EIO);
+                       done_lh(&dotdot_lh);
+               }
+       }
+       reiser4_update_dir(new_dir);
+       reiser4_update_dir(old_dir);
+       reiser4_update_sd(old_inode);
+       if (result == 0) {
+               file_plugin *fplug;
+
+               if (new_inode != NULL) {
+                       /* add safe-link for target file (in case we removed
+                        * last reference to the poor fellow */
+                       fplug = inode_file_plugin(new_inode);
+                       if (new_inode->i_nlink == 0)
+                               result = safe_link_add(new_inode, SAFE_UNLINK);
+               }
+       }
+      exit:
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+       return result;
+}
+#endif
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/acl.h linux-2.6.20/fs/reiser4/plugin/item/acl.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/acl.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/acl.h   2007-05-06 14:50:43.799006970 +0400
@@ -0,0 +1,66 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Directory entry. */
+
+#if !defined( __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__ )
+#define __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../key.h"
+
+#include <linux/fs.h>
+#include <linux/dcache.h>      /* for struct dentry */
+
+typedef struct directory_entry_format {
+       /* key of object stat-data. It's not necessary to store whole
+          key here, because it's always key of stat-data, so minor
+          packing locality and offset can be omitted here. But this
+          relies on particular key allocation scheme for stat-data, so,
+          for extensibility sake, whole key can be stored here.
+
+          We store key as array of bytes, because we don't want 8-byte
+          alignment of dir entries.
+        */
+       obj_key_id id;
+       /* file name. Null terminated string. */
+       d8 name[0];
+} directory_entry_format;
+
+void print_de(const char *prefix, coord_t * coord);
+int extract_key_de(const coord_t * coord, reiser4_key * key);
+int update_key_de(const coord_t * coord, const reiser4_key * key,
+                 lock_handle * lh);
+char *extract_name_de(const coord_t * coord, char *buf);
+unsigned extract_file_type_de(const coord_t * coord);
+int add_entry_de(struct inode *dir, coord_t * coord,
+                lock_handle * lh, const struct dentry *name,
+                reiser4_dir_entry_desc * entry);
+int rem_entry_de(struct inode *dir, const struct qstr *name, coord_t * coord,
+                lock_handle * lh, reiser4_dir_entry_desc * entry);
+int max_name_len_de(const struct inode *dir);
+
+int de_rem_and_shrink(struct inode *dir, coord_t * coord, int length);
+
+char *extract_dent_name(const coord_t * coord,
+                       directory_entry_format * dent, char *buf);
+
+#if REISER4_LARGE_KEY
+#define DE_NAME_BUF_LEN (24)
+#else
+#define DE_NAME_BUF_LEN (16)
+#endif
+
+/* __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/blackbox.c linux-2.6.20/fs/reiser4/plugin/item/blackbox.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/blackbox.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/blackbox.c      2007-05-06 14:50:43.799006970 +0400
@@ -0,0 +1,142 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Black box item implementation */
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../coord.h"
+#include "../../tree.h"
+#include "../../lock.h"
+
+#include "blackbox.h"
+#include "item.h"
+#include "../plugin.h"
+
+int
+store_black_box(reiser4_tree * tree,
+               const reiser4_key * key, void *data, int length)
+{
+       int result;
+       reiser4_item_data idata;
+       coord_t coord;
+       lock_handle lh;
+
+       memset(&idata, 0, sizeof idata);
+
+       idata.data = data;
+       idata.user = 0;
+       idata.length = length;
+       idata.iplug = item_plugin_by_id(BLACK_BOX_ID);
+
+       init_lh(&lh);
+       result = insert_by_key(tree, key,
+                              &idata, &coord, &lh, LEAF_LEVEL, CBK_UNIQUE);
+
+       assert("nikita-3413",
+              ergo(result == 0,
+                   WITH_COORD(&coord,
+                              item_length_by_coord(&coord) == length)));
+
+       done_lh(&lh);
+       return result;
+}
+
+int
+load_black_box(reiser4_tree * tree,
+              reiser4_key * key, void *data, int length, int exact)
+{
+       int result;
+       coord_t coord;
+       lock_handle lh;
+
+       init_lh(&lh);
+       result = coord_by_key(tree, key,
+                             &coord, &lh, ZNODE_READ_LOCK,
+                             exact ? FIND_EXACT : FIND_MAX_NOT_MORE_THAN,
+                             LEAF_LEVEL, LEAF_LEVEL, CBK_UNIQUE, NULL);
+
+       if (result == 0) {
+               int ilen;
+
+               result = zload(coord.node);
+               if (result == 0) {
+                       ilen = item_length_by_coord(&coord);
+                       if (ilen <= length) {
+                               memcpy(data, item_body_by_coord(&coord), ilen);
+                               unit_key_by_coord(&coord, key);
+                       } else if (exact) {
+                               /*
+                                * item is larger than buffer provided by the
+                                * user. Only issue a warning if @exact is
+                                * set. If @exact is false, we are iterating
+                                * over all safe-links and here we are reaching
+                                * the end of the iteration.
+                                */
+                               warning("nikita-3415",
+                                       "Wrong black box length: %i > %i",
+                                       ilen, length);
+                               result = RETERR(-EIO);
+                       }
+                       zrelse(coord.node);
+               }
+       }
+
+       done_lh(&lh);
+       return result;
+
+}
+
+int
+update_black_box(reiser4_tree * tree,
+                const reiser4_key * key, void *data, int length)
+{
+       int result;
+       coord_t coord;
+       lock_handle lh;
+
+       init_lh(&lh);
+       result = coord_by_key(tree, key,
+                             &coord, &lh, ZNODE_READ_LOCK,
+                             FIND_EXACT,
+                             LEAF_LEVEL, LEAF_LEVEL, CBK_UNIQUE, NULL);
+       if (result == 0) {
+               int ilen;
+
+               result = zload(coord.node);
+               if (result == 0) {
+                       ilen = item_length_by_coord(&coord);
+                       if (length <= ilen) {
+                               memcpy(item_body_by_coord(&coord), data,
+                                      length);
+                       } else {
+                               warning("nikita-3437",
+                                       "Wrong black box length: %i < %i",
+                                       ilen, length);
+                               result = RETERR(-EIO);
+                       }
+                       zrelse(coord.node);
+               }
+       }
+
+       done_lh(&lh);
+       return result;
+
+}
+
+int kill_black_box(reiser4_tree * tree, const reiser4_key * key)
+{
+       return reiser4_cut_tree(tree, key, key, NULL, 1);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/blackbox.h linux-2.6.20/fs/reiser4/plugin/item/blackbox.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/blackbox.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/blackbox.h      2007-05-06 14:50:43.799006970 +0400
@@ -0,0 +1,33 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* "Black box" entry to fixed-width contain user supplied data */
+
+#if !defined( __FS_REISER4_BLACK_BOX_H__ )
+#define __FS_REISER4_BLACK_BOX_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../key.h"
+
+extern int store_black_box(reiser4_tree * tree,
+                          const reiser4_key * key, void *data, int length);
+extern int load_black_box(reiser4_tree * tree,
+                         reiser4_key * key, void *data, int length, int exact);
+extern int kill_black_box(reiser4_tree * tree, const reiser4_key * key);
+extern int update_black_box(reiser4_tree * tree,
+                           const reiser4_key * key, void *data, int length);
+
+/* __FS_REISER4_BLACK_BOX_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/cde.c linux-2.6.20/fs/reiser4/plugin/item/cde.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/cde.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/cde.c   2007-05-06 14:50:43.799006970 +0400
@@ -0,0 +1,1008 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Directory entry implementation */
+
+/* DESCRIPTION:
+
+   This is "compound" directory item plugin implementation. This directory
+   item type is compound (as opposed to the "simple directory item" in
+   fs/reiser4/plugin/item/sde.[ch]), because it consists of several directory
+   entries.
+
+   The reason behind this decision is disk space efficiency: all directory
+   entries inside the same directory have identical fragment in their
+   keys. This, of course, depends on key assignment policy. In our default key
+   assignment policy, all directory entries have the same locality which is
+   equal to the object id of their directory.
+
+   Composing directory item out of several directory entries for the same
+   directory allows us to store said key fragment only once. That is, this is
+   some ad hoc form of key compression (stem compression) that is implemented
+   here, because general key compression is not supposed to be implemented in
+   v4.0.
+
+   Another decision that was made regarding all directory item plugins, is
+   that they will store entry keys unaligned. This is for that sake of disk
+   space efficiency again.
+
+   In should be noted, that storing keys unaligned increases CPU consumption,
+   at least on some architectures.
+
+   Internal on-disk structure of the compound directory item is the following:
+
+        HEADER          cde_item_format.        Here number of entries is stored.
+        ENTRY_HEADER_0  cde_unit_header.        Here part of entry key and
+        ENTRY_HEADER_1                          offset of entry body are stored.
+        ENTRY_HEADER_2                         (basically two last parts of key)
+        ...
+        ENTRY_HEADER_N
+        ENTRY_BODY_0    directory_entry_format. Here part of stat data key and
+        ENTRY_BODY_1                            NUL-terminated name are stored.
+        ENTRY_BODY_2                           (part of statadta key in the
+                                                sence that since all SDs have
+                                                zero offset, this offset is not
+                                                stored on disk).
+        ...
+        ENTRY_BODY_N
+
+   When it comes to the balancing, each directory entry in compound directory
+   item is unit, that is, something that can be cut from one item and pasted
+   into another item of the same type. Handling of unit cut and paste is major
+   reason for the complexity of code below.
+
+*/
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "sde.h"
+#include "cde.h"
+#include "item.h"
+#include "../node/node.h"
+#include "../plugin.h"
+#include "../../znode.h"
+#include "../../carry.h"
+#include "../../tree.h"
+#include "../../inode.h"
+
+#include <linux/fs.h>          /* for struct inode */
+#include <linux/dcache.h>      /* for struct dentry */
+#include <linux/quotaops.h>
+
+#if 0
+#define CHECKME(coord)                                         \
+({                                                             \
+       const char *message;                                    \
+       coord_t dup;                                            \
+                                                               \
+       coord_dup_nocheck(&dup, (coord));                       \
+       dup.unit_pos = 0;                                       \
+       assert("nikita-2871", cde_check(&dup, &message) == 0);  \
+})
+#else
+#define CHECKME(coord) noop
+#endif
+
+/* return body of compound directory item at @coord */
+static inline cde_item_format *formatted_at(const coord_t * coord)
+{
+       assert("nikita-1282", coord != NULL);
+       return item_body_by_coord(coord);
+}
+
+/* return entry header at @coord */
+static inline cde_unit_header *header_at(const coord_t *
+                                        coord /* coord of item */ ,
+                                        int idx /* index of unit */ )
+{
+       assert("nikita-1283", coord != NULL);
+       return &formatted_at(coord)->entry[idx];
+}
+
+/* return number of units in compound directory item at @coord */
+static int units(const coord_t * coord /* coord of item */ )
+{
+       return le16_to_cpu(get_unaligned(&formatted_at(coord)->num_of_entries));
+}
+
+/* return offset of the body of @idx-th entry in @coord */
+static unsigned int offset_of(const coord_t * coord /* coord of item */ ,
+                             int idx /* index of unit */ )
+{
+       if (idx < units(coord))
+               return le16_to_cpu(get_unaligned(&header_at(coord, idx)->offset));
+       else if (idx == units(coord))
+               return item_length_by_coord(coord);
+       else
+               impossible("nikita-1308", "Wrong idx");
+       return 0;
+}
+
+/* set offset of the body of @idx-th entry in @coord */
+static void set_offset(const coord_t * coord /* coord of item */ ,
+                      int idx /* index of unit */ ,
+                      unsigned int offset /* new offset */ )
+{
+       put_unaligned(cpu_to_le16((__u16) offset), &header_at(coord, idx)->offset);
+}
+
+static void adj_offset(const coord_t * coord /* coord of item */ ,
+                      int idx /* index of unit */ ,
+                      int delta /* offset change */ )
+{
+       d16 *doffset;
+       __u16 offset;
+
+       doffset = &header_at(coord, idx)->offset;
+       offset = le16_to_cpu(get_unaligned(doffset));
+       offset += delta;
+       put_unaligned(cpu_to_le16((__u16) offset), doffset);
+}
+
+/* return pointer to @offset-th byte from the beginning of @coord */
+static char *address(const coord_t * coord /* coord of item */ ,
+                    int offset)
+{
+       return ((char *)item_body_by_coord(coord)) + offset;
+}
+
+/* return pointer to the body of @idx-th entry in @coord */
+static directory_entry_format *entry_at(const coord_t * coord  /* coord of
+                                                                * item */ ,
+                                       int idx /* index of unit */ )
+{
+       return (directory_entry_format *) address(coord,
+                                                 (int)offset_of(coord, idx));
+}
+
+/* return number of unit referenced by @coord */
+static int idx_of(const coord_t * coord /* coord of item */ )
+{
+       assert("nikita-1285", coord != NULL);
+       return coord->unit_pos;
+}
+
+/* find position where entry with @entry_key would be inserted into @coord */
+static int find(const coord_t * coord /* coord of item */ ,
+               const reiser4_key * entry_key /* key to look for */ ,
+               cmp_t * last /* result of last comparison */ )
+{
+       int entries;
+
+       int left;
+       int right;
+
+       cde_unit_header *header;
+
+       assert("nikita-1295", coord != NULL);
+       assert("nikita-1296", entry_key != NULL);
+       assert("nikita-1297", last != NULL);
+
+       entries = units(coord);
+       left = 0;
+       right = entries - 1;
+       while (right - left >= REISER4_SEQ_SEARCH_BREAK) {
+               int median;
+
+               median = (left + right) >> 1;
+
+               header = header_at(coord, median);
+               *last = de_id_key_cmp(&header->hash, entry_key);
+               switch (*last) {
+               case LESS_THAN:
+                       left = median;
+                       break;
+               case GREATER_THAN:
+                       right = median;
+                       break;
+               case EQUAL_TO:{
+                               do {
+                                       median--;
+                                       header--;
+                               } while (median >= 0 &&
+                                        de_id_key_cmp(&header->hash,
+                                                      entry_key) == EQUAL_TO);
+                               return median + 1;
+                       }
+               }
+       }
+       header = header_at(coord, left);
+       for (; left < entries; ++left, ++header) {
+               prefetch(header + 1);
+               *last = de_id_key_cmp(&header->hash, entry_key);
+               if (*last != LESS_THAN)
+                       break;
+       }
+       if (left < entries)
+               return left;
+       else
+               return RETERR(-ENOENT);
+
+}
+
+/* expand @coord as to accommodate for insertion of @no new entries starting
+   from @pos, with total bodies size @size. */
+static int expand_item(const coord_t * coord /* coord of item */ ,
+                      int pos /* unit position */ , int no     /* number of new
+                                                                * units*/ ,
+                      int size /* total size of new units' data */ ,
+                      unsigned int data_size   /* free space already reserved
+                                                * in the item for insertion */ )
+{
+       int entries;
+       cde_unit_header *header;
+       char *dent;
+       int i;
+
+       assert("nikita-1310", coord != NULL);
+       assert("nikita-1311", pos >= 0);
+       assert("nikita-1312", no > 0);
+       assert("nikita-1313", data_size >= no * sizeof(directory_entry_format));
+       assert("nikita-1343",
+              item_length_by_coord(coord) >=
+              (int)(size + data_size + no * sizeof *header));
+
+       entries = units(coord);
+
+       if (pos == entries)
+               dent = address(coord, size);
+       else
+               dent = (char *)entry_at(coord, pos);
+       /* place where new header will be in */
+       header = header_at(coord, pos);
+       /* free space for new entry headers */
+       memmove(header + no, header,
+               (unsigned)(address(coord, size) - (char *)header));
+       /* if adding to the end initialise first new header */
+       if (pos == entries) {
+               set_offset(coord, pos, (unsigned)size);
+       }
+
+       /* adjust entry pointer and size */
+       dent = dent + no * sizeof *header;
+       size += no * sizeof *header;
+       /* free space for new entries */
+       memmove(dent + data_size, dent,
+               (unsigned)(address(coord, size) - dent));
+
+       /* increase counter */
+       entries += no;
+       put_unaligned(cpu_to_le16((__u16) entries), &formatted_at(coord)->num_of_entries);
+
+       /* [ 0 ... pos ] entries were shifted by no * ( sizeof *header )
+          bytes.  */
+       for (i = 0; i <= pos; ++i)
+               adj_offset(coord, i, no * sizeof *header);
+       /* [ pos + no ... +\infty ) entries were shifted by ( no *
+          sizeof *header + data_size ) bytes */
+       for (i = pos + no; i < entries; ++i)
+               adj_offset(coord, i, no * sizeof *header + data_size);
+       return 0;
+}
+
+/* insert new @entry into item */
+static int expand(const coord_t * coord /* coord of item */ ,
+                 cde_entry * entry /* entry to insert */ ,
+                 int len /* length of @entry data */ ,
+                 int *pos /* position to insert */ ,
+                 reiser4_dir_entry_desc * dir_entry    /* parameters for new
+                                                        * entry */ )
+{
+       cmp_t cmp_res;
+       int datasize;
+
+       *pos = find(coord, &dir_entry->key, &cmp_res);
+       if (*pos < 0)
+               *pos = units(coord);
+
+       datasize = sizeof(directory_entry_format);
+       if (is_longname(entry->name->name, entry->name->len))
+               datasize += entry->name->len + 1;
+
+       expand_item(coord, *pos, 1, item_length_by_coord(coord) - len,
+                   datasize);
+       return 0;
+}
+
+/* paste body of @entry into item */
+static int paste_entry(const coord_t * coord /* coord of item */ ,
+                      cde_entry * entry /* new entry */ ,
+                      int pos /* position to insert */ ,
+                      reiser4_dir_entry_desc * dir_entry       /* parameters for
+                                                                * new entry */ )
+{
+       cde_unit_header *header;
+       directory_entry_format *dent;
+       const char *name;
+       int len;
+
+       header = header_at(coord, pos);
+       dent = entry_at(coord, pos);
+
+       build_de_id_by_key(&dir_entry->key, &header->hash);
+       build_inode_key_id(entry->obj, &dent->id);
+       /* AUDIT unsafe strcpy() operation! It should be replaced with
+          much less CPU hungry
+          memcpy( ( char * ) dent -> name, entry -> name -> name , entry -> name -> len );
+
+          Also a more major thing is that there should be a way to figure out
+          amount of space in dent -> name and be able to check that we are
+          not going to overwrite more than we supposed to */
+       name = entry->name->name;
+       len = entry->name->len;
+       if (is_longname(name, len)) {
+               strcpy((unsigned char *)dent->name, name);
+               put_unaligned(0, &dent->name[len]);
+       }
+       return 0;
+}
+
+/* estimate how much space is necessary in item to insert/paste set of entries
+   described in @data. */
+int estimate_cde(const coord_t * coord /* coord of item */ ,
+                const reiser4_item_data * data /* parameters for new item */ )
+{
+       cde_entry_data *e;
+       int result;
+       int i;
+
+       e = (cde_entry_data *) data->data;
+
+       assert("nikita-1288", e != NULL);
+       assert("nikita-1289", e->num_of_entries >= 0);
+
+       if (coord == NULL)
+               /* insert */
+               result = sizeof(cde_item_format);
+       else
+               /* paste */
+               result = 0;
+
+       result += e->num_of_entries *
+           (sizeof(cde_unit_header) + sizeof(directory_entry_format));
+       for (i = 0; i < e->num_of_entries; ++i) {
+               const char *name;
+               int len;
+
+               name = e->entry[i].name->name;
+               len = e->entry[i].name->len;
+               assert("nikita-2054", strlen(name) == len);
+               if (is_longname(name, len))
+                       result += len + 1;
+       }
+       ((reiser4_item_data *) data)->length = result;
+       return result;
+}
+
+/* ->nr_units() method for this item plugin. */
+pos_in_node_t nr_units_cde(const coord_t * coord /* coord of item */ )
+{
+       return units(coord);
+}
+
+/* ->unit_key() method for this item plugin. */
+reiser4_key *unit_key_cde(const coord_t * coord /* coord of item */ ,
+                         reiser4_key * key /* resulting key */ )
+{
+       assert("nikita-1452", coord != NULL);
+       assert("nikita-1345", idx_of(coord) < units(coord));
+       assert("nikita-1346", key != NULL);
+
+       item_key_by_coord(coord, key);
+       extract_key_from_de_id(extract_dir_id_from_key(key),
+                              &header_at(coord, idx_of(coord))->hash, key);
+       return key;
+}
+
+/* mergeable_cde(): implementation of ->mergeable() item method.
+
+   Two directory items are mergeable iff they are from the same
+   directory. That simple.
+
+*/
+int mergeable_cde(const coord_t * p1 /* coord of first item */ ,
+                 const coord_t * p2 /* coord of second item */ )
+{
+       reiser4_key k1;
+       reiser4_key k2;
+
+       assert("nikita-1339", p1 != NULL);
+       assert("nikita-1340", p2 != NULL);
+
+       return
+           (item_plugin_by_coord(p1) == item_plugin_by_coord(p2)) &&
+           (extract_dir_id_from_key(item_key_by_coord(p1, &k1)) ==
+            extract_dir_id_from_key(item_key_by_coord(p2, &k2)));
+
+}
+
+/* ->max_key_inside() method for this item plugin. */
+reiser4_key *max_key_inside_cde(const coord_t * coord /* coord of item */ ,
+                               reiser4_key * result /* resulting key */ )
+{
+       assert("nikita-1342", coord != NULL);
+
+       item_key_by_coord(coord, result);
+       set_key_ordering(result, get_key_ordering(reiser4_max_key()));
+       set_key_fulloid(result, get_key_fulloid(reiser4_max_key()));
+       set_key_offset(result, get_key_offset(reiser4_max_key()));
+       return result;
+}
+
+/* @data contains data which are to be put into tree */
+int can_contain_key_cde(const coord_t * coord /* coord of item */ ,
+                       const reiser4_key * key /* key to check */ ,
+                       const reiser4_item_data * data  /* parameters of new
+                                                        * item/unit being
+                                                        * created */ )
+{
+       reiser4_key item_key;
+
+       /* FIXME-VS: do not rely on anything but iplug field of @data. Only
+          data->iplug is initialized */
+       assert("vs-457", data && data->iplug);
+/*     assert( "vs-553", data -> user == 0 );*/
+       item_key_by_coord(coord, &item_key);
+
+       return (item_plugin_by_coord(coord) == data->iplug) &&
+           (extract_dir_id_from_key(&item_key) ==
+            extract_dir_id_from_key(key));
+}
+
+#if REISER4_DEBUG
+/* cde_check ->check() method for compressed directory items
+
+   used for debugging, every item should have here the most complete
+   possible check of the consistency of the item that the inventor can
+   construct
+*/
+int reiser4_check_cde(const coord_t * coord /* coord of item to check */,
+                     const char **error /* where to store error message */)
+{
+       int i;
+       int result;
+       char *item_start;
+       char *item_end;
+       reiser4_key key;
+
+       coord_t c;
+
+       assert("nikita-1357", coord != NULL);
+       assert("nikita-1358", error != NULL);
+
+       if (!ergo(coord->item_pos != 0,
+                 is_dot_key(item_key_by_coord(coord, &key)))) {
+               *error = "CDE doesn't start with dot";
+               return -1;
+       }
+       item_start = item_body_by_coord(coord);
+       item_end = item_start + item_length_by_coord(coord);
+
+       coord_dup(&c, coord);
+       result = 0;
+       for (i = 0; i < units(coord); ++i) {
+               directory_entry_format *entry;
+
+               if ((char *)(header_at(coord, i) + 1) >
+                   item_end - units(coord) * sizeof *entry) {
+                       *error = "CDE header is out of bounds";
+                       result = -1;
+                       break;
+               }
+               entry = entry_at(coord, i);
+               if ((char *)entry < item_start + sizeof(cde_item_format)) {
+                       *error = "CDE header is too low";
+                       result = -1;
+                       break;
+               }
+               if ((char *)(entry + 1) > item_end) {
+                       *error = "CDE header is too high";
+                       result = -1;
+                       break;
+               }
+       }
+
+       return result;
+}
+#endif
+
+/* ->init() method for this item plugin. */
+int init_cde(coord_t * coord /* coord of item */ ,
+            coord_t * from UNUSED_ARG, reiser4_item_data * data        /* structure used for insertion */
+            UNUSED_ARG)
+{
+       put_unaligned(cpu_to_le16(0), &formatted_at(coord)->num_of_entries);
+       return 0;
+}
+
+/* ->lookup() method for this item plugin. */
+lookup_result lookup_cde(const reiser4_key * key /* key to search for */ ,
+                        lookup_bias bias /* search bias */ ,
+                        coord_t * coord /* coord of item to lookup in */ )
+{
+       cmp_t last_comp;
+       int pos;
+
+       reiser4_key utmost_key;
+
+       assert("nikita-1293", coord != NULL);
+       assert("nikita-1294", key != NULL);
+
+       CHECKME(coord);
+
+       if (keygt(item_key_by_coord(coord, &utmost_key), key)) {
+               coord->unit_pos = 0;
+               coord->between = BEFORE_UNIT;
+               return CBK_COORD_NOTFOUND;
+       }
+       pos = find(coord, key, &last_comp);
+       if (pos >= 0) {
+               coord->unit_pos = (int)pos;
+               switch (last_comp) {
+               case EQUAL_TO:
+                       coord->between = AT_UNIT;
+                       return CBK_COORD_FOUND;
+               case GREATER_THAN:
+                       coord->between = BEFORE_UNIT;
+                       return RETERR(-ENOENT);
+               case LESS_THAN:
+               default:
+                       impossible("nikita-1298", "Broken find");
+                       return RETERR(-EIO);
+               }
+       } else {
+               coord->unit_pos = units(coord) - 1;
+               coord->between = AFTER_UNIT;
+               return (bias ==
+                       FIND_MAX_NOT_MORE_THAN) ? CBK_COORD_FOUND :
+                   CBK_COORD_NOTFOUND;
+       }
+}
+
+/* ->paste() method for this item plugin. */
+int paste_cde(coord_t * coord /* coord of item */ ,
+             reiser4_item_data * data  /* parameters of new unit being
+                                        * inserted */ ,
+             carry_plugin_info * info UNUSED_ARG /* todo carry queue */ )
+{
+       cde_entry_data *e;
+       int result;
+       int i;
+
+       CHECKME(coord);
+       e = (cde_entry_data *) data->data;
+
+       result = 0;
+       for (i = 0; i < e->num_of_entries; ++i) {
+               int pos;
+               int phantom_size;
+
+               phantom_size = data->length;
+               if (units(coord) == 0)
+                       phantom_size -= sizeof(cde_item_format);
+
+               result =
+                   expand(coord, e->entry + i, phantom_size, &pos, data->arg);
+               if (result != 0)
+                       break;
+               result = paste_entry(coord, e->entry + i, pos, data->arg);
+               if (result != 0)
+                       break;
+       }
+       CHECKME(coord);
+       return result;
+}
+
+/* amount of space occupied by all entries starting from @idx both headers and
+   bodies. */
+static unsigned int part_size(const coord_t * coord /* coord of item */ ,
+                             int idx /* index of unit */ )
+{
+       assert("nikita-1299", coord != NULL);
+       assert("nikita-1300", idx < (int)units(coord));
+
+       return sizeof(cde_item_format) +
+           (idx + 1) * sizeof(cde_unit_header) + offset_of(coord,
+                                                           idx + 1) -
+           offset_of(coord, 0);
+}
+
+/* how many but not more than @want units of @source can be merged with
+   item in @target node. If pend == append - we try to append last item
+   of @target by first units of @source. If pend == prepend - we try to
+   "prepend" first item in @target by last units of @source. @target
+   node has @free_space bytes of free space. Total size of those units
+   are returned via @size */
+int can_shift_cde(unsigned free_space /* free space in item */ ,
+                 coord_t * coord /* coord of source item */ ,
+                 znode * target /* target node */ ,
+                 shift_direction pend /* shift direction */ ,
+                 unsigned *size /* resulting number of shifted bytes */ ,
+                 unsigned want /* maximal number of bytes to shift */ )
+{
+       int shift;
+
+       CHECKME(coord);
+       if (want == 0) {
+               *size = 0;
+               return 0;
+       }
+
+       /* pend == SHIFT_LEFT <==> shifting to the left */
+       if (pend == SHIFT_LEFT) {
+               for (shift = min((int)want - 1, units(coord)); shift >= 0;
+                    --shift) {
+                       *size = part_size(coord, shift);
+                       if (target != NULL)
+                               *size -= sizeof(cde_item_format);
+                       if (*size <= free_space)
+                               break;
+               }
+               shift = shift + 1;
+       } else {
+               int total_size;
+
+               assert("nikita-1301", pend == SHIFT_RIGHT);
+
+               total_size = item_length_by_coord(coord);
+               for (shift = units(coord) - want - 1; shift < units(coord) - 1;
+                    ++shift) {
+                       *size = total_size - part_size(coord, shift);
+                       if (target == NULL)
+                               *size += sizeof(cde_item_format);
+                       if (*size <= free_space)
+                               break;
+               }
+               shift = units(coord) - shift - 1;
+       }
+       if (shift == 0)
+               *size = 0;
+       CHECKME(coord);
+       return shift;
+}
+
+/* ->copy_units() method for this item plugin. */
+void copy_units_cde(coord_t * target /* coord of target item */ ,
+                   coord_t * source /* coord of source item */ ,
+                   unsigned from /* starting unit */ ,
+                   unsigned count /* how many units to copy */ ,
+                   shift_direction where_is_free_space /* shift direction */ ,
+                   unsigned free_space /* free space in item */ )
+{
+       char *header_from;
+       char *header_to;
+
+       char *entry_from;
+       char *entry_to;
+
+       int pos_in_target;
+       int data_size;
+       int data_delta;
+       int i;
+
+       assert("nikita-1303", target != NULL);
+       assert("nikita-1304", source != NULL);
+       assert("nikita-1305", (int)from < units(source));
+       assert("nikita-1307", (int)(from + count) <= units(source));
+
+       if (where_is_free_space == SHIFT_LEFT) {
+               assert("nikita-1453", from == 0);
+               pos_in_target = units(target);
+       } else {
+               assert("nikita-1309", (int)(from + count) == units(source));
+               pos_in_target = 0;
+               memmove(item_body_by_coord(target),
+                       (char *)item_body_by_coord(target) + free_space,
+                       item_length_by_coord(target) - free_space);
+       }
+
+       CHECKME(target);
+       CHECKME(source);
+
+       /* expand @target */
+       data_size =
+           offset_of(source, (int)(from + count)) - offset_of(source,
+                                                              (int)from);
+
+       if (units(target) == 0)
+               free_space -= sizeof(cde_item_format);
+
+       expand_item(target, pos_in_target, (int)count,
+                   (int)(item_length_by_coord(target) - free_space),
+                   (unsigned)data_size);
+
+       /* copy first @count units of @source into @target */
+       data_delta =
+           offset_of(target, pos_in_target) - offset_of(source, (int)from);
+
+       /* copy entries */
+       entry_from = (char *)entry_at(source, (int)from);
+       entry_to = (char *)entry_at(source, (int)(from + count));
+       memmove(entry_at(target, pos_in_target), entry_from,
+               (unsigned)(entry_to - entry_from));
+
+       /* copy headers */
+       header_from = (char *)header_at(source, (int)from);
+       header_to = (char *)header_at(source, (int)(from + count));
+       memmove(header_at(target, pos_in_target), header_from,
+               (unsigned)(header_to - header_from));
+
+       /* update offsets */
+       for (i = pos_in_target; i < (int)(pos_in_target + count); ++i)
+               adj_offset(target, i, data_delta);
+       CHECKME(target);
+       CHECKME(source);
+}
+
+/* ->cut_units() method for this item plugin. */
+int cut_units_cde(coord_t * coord /* coord of item */ ,
+                 pos_in_node_t from /* start unit pos */ ,
+                 pos_in_node_t to /* stop unit pos */ ,
+                 struct carry_cut_data *cdata UNUSED_ARG,
+                 reiser4_key * smallest_removed, reiser4_key * new_first)
+{
+       char *header_from;
+       char *header_to;
+
+       char *entry_from;
+       char *entry_to;
+
+       int size;
+       int entry_delta;
+       int header_delta;
+       int i;
+
+       unsigned count;
+
+       CHECKME(coord);
+
+       count = to - from + 1;
+
+       assert("nikita-1454", coord != NULL);
+       assert("nikita-1455", (int)(from + count) <= units(coord));
+
+       if (smallest_removed)
+               unit_key_by_coord(coord, smallest_removed);
+
+       if (new_first) {
+               coord_t next;
+
+               /* not everything is cut from item head */
+               assert("vs-1527", from == 0);
+               assert("vs-1528", to < units(coord) - 1);
+
+               coord_dup(&next, coord);
+               next.unit_pos++;
+               unit_key_by_coord(&next, new_first);
+       }
+
+       size = item_length_by_coord(coord);
+       if (count == (unsigned)units(coord)) {
+               return size;
+       }
+
+       header_from = (char *)header_at(coord, (int)from);
+       header_to = (char *)header_at(coord, (int)(from + count));
+
+       entry_from = (char *)entry_at(coord, (int)from);
+       entry_to = (char *)entry_at(coord, (int)(from + count));
+
+       /* move headers */
+       memmove(header_from, header_to,
+               (unsigned)(address(coord, size) - header_to));
+
+       header_delta = header_to - header_from;
+
+       entry_from -= header_delta;
+       entry_to -= header_delta;
+       size -= header_delta;
+
+       /* copy entries */
+       memmove(entry_from, entry_to,
+               (unsigned)(address(coord, size) - entry_to));
+
+       entry_delta = entry_to - entry_from;
+       size -= entry_delta;
+
+       /* update offsets */
+
+       for (i = 0; i < (int)from; ++i)
+               adj_offset(coord, i, -header_delta);
+
+       for (i = from; i < units(coord) - (int)count; ++i)
+               adj_offset(coord, i, -header_delta - entry_delta);
+
+       put_unaligned(cpu_to_le16((__u16) units(coord) - count),
+                     &formatted_at(coord)->num_of_entries);
+
+       if (from == 0) {
+               /* entries from head was removed - move remaining to right */
+               memmove((char *)item_body_by_coord(coord) +
+                       header_delta + entry_delta, item_body_by_coord(coord),
+                       (unsigned)size);
+               if (REISER4_DEBUG)
+                       memset(item_body_by_coord(coord), 0,
+                              (unsigned)header_delta + entry_delta);
+       } else {
+               /* freed space is already at the end of item */
+               if (REISER4_DEBUG)
+                       memset((char *)item_body_by_coord(coord) + size, 0,
+                              (unsigned)header_delta + entry_delta);
+       }
+
+       return header_delta + entry_delta;
+}
+
+int kill_units_cde(coord_t * coord /* coord of item */ ,
+                  pos_in_node_t from /* start unit pos */ ,
+                  pos_in_node_t to /* stop unit pos */ ,
+                  struct carry_kill_data *kdata UNUSED_ARG,
+                  reiser4_key * smallest_removed, reiser4_key * new_first)
+{
+       return cut_units_cde(coord, from, to, NULL, smallest_removed, new_first);
+}
+
+/* ->s.dir.extract_key() method for this item plugin. */
+int extract_key_cde(const coord_t * coord /* coord of item */ ,
+                   reiser4_key * key /* resulting key */ )
+{
+       directory_entry_format *dent;
+
+       assert("nikita-1155", coord != NULL);
+       assert("nikita-1156", key != NULL);
+
+       dent = entry_at(coord, idx_of(coord));
+       return extract_key_from_id(&dent->id, key);
+}
+
+int
+update_key_cde(const coord_t * coord, const reiser4_key * key,
+              lock_handle * lh UNUSED_ARG)
+{
+       directory_entry_format *dent;
+       obj_key_id obj_id;
+       int result;
+
+       assert("nikita-2344", coord != NULL);
+       assert("nikita-2345", key != NULL);
+
+       dent = entry_at(coord, idx_of(coord));
+       result = build_obj_key_id(key, &obj_id);
+       if (result == 0) {
+               dent->id = obj_id;
+               znode_make_dirty(coord->node);
+       }
+       return 0;
+}
+
+/* ->s.dir.extract_name() method for this item plugin. */
+char *extract_name_cde(const coord_t * coord /* coord of item */ , char *buf)
+{
+       directory_entry_format *dent;
+
+       assert("nikita-1157", coord != NULL);
+
+       dent = entry_at(coord, idx_of(coord));
+       return extract_dent_name(coord, dent, buf);
+}
+
+static int cde_bytes(int pasting, const reiser4_item_data * data)
+{
+       int result;
+
+       result = data->length;
+       if (!pasting)
+               result -= sizeof(cde_item_format);
+       return result;
+}
+
+/* ->s.dir.add_entry() method for this item plugin */
+int add_entry_cde(struct inode *dir /* directory object */ ,
+                 coord_t * coord /* coord of item */ ,
+                 lock_handle * lh /* lock handle for insertion */ ,
+                 const struct dentry *name /* name to insert */ ,
+                 reiser4_dir_entry_desc * dir_entry    /* parameters of new
+                                                        * directory entry */ )
+{
+       reiser4_item_data data;
+       cde_entry entry;
+       cde_entry_data edata;
+       int result;
+
+       assert("nikita-1656", coord->node == lh->node);
+       assert("nikita-1657", znode_is_write_locked(coord->node));
+
+       edata.num_of_entries = 1;
+       edata.entry = &entry;
+
+       entry.dir = dir;
+       entry.obj = dir_entry->obj;
+       entry.name = &name->d_name;
+
+       data.data = (char *)&edata;
+       data.user = 0;          /* &edata is not user space */
+       data.iplug = item_plugin_by_id(COMPOUND_DIR_ID);
+       data.arg = dir_entry;
+       assert("nikita-1302", data.iplug != NULL);
+
+       result = is_dot_key(&dir_entry->key);
+       data.length = estimate_cde(result ? coord : NULL, &data);
+
+       /* NOTE-NIKITA quota plugin? */
+       if (DQUOT_ALLOC_SPACE_NODIRTY(dir, cde_bytes(result, &data)))
+               return RETERR(-EDQUOT);
+
+       if (result)
+               result = insert_by_coord(coord, &data, &dir_entry->key, lh, 0);
+       else
+               result = reiser4_resize_item(coord, &data, &dir_entry->key,
+                                            lh, 0);
+       return result;
+}
+
+/* ->s.dir.rem_entry() */
+int rem_entry_cde(struct inode *dir /* directory of item */ ,
+                 const struct qstr *name, coord_t * coord /* coord of item */ ,
+                 lock_handle * lh UNUSED_ARG   /* lock handle for
+                                                * removal */ ,
+                 reiser4_dir_entry_desc * entry UNUSED_ARG     /* parameters of
+                                                                * directory entry
+                                                                * being removed */ )
+{
+       coord_t shadow;
+       int result;
+       int length;
+       ON_DEBUG(char buf[DE_NAME_BUF_LEN]);
+
+       assert("nikita-2870", strlen(name->name) == name->len);
+       assert("nikita-2869",
+              !strcmp(name->name, extract_name_cde(coord, buf)));
+
+       length = sizeof(directory_entry_format) + sizeof(cde_unit_header);
+       if (is_longname(name->name, name->len))
+               length += name->len + 1;
+
+       if (inode_get_bytes(dir) < length) {
+               warning("nikita-2628", "Dir is broke: %llu: %llu",
+                       (unsigned long long)get_inode_oid(dir),
+                       inode_get_bytes(dir));
+
+               return RETERR(-EIO);
+       }
+
+       /* cut_node() is supposed to take pointers to _different_
+          coords, because it will modify them without respect to
+          possible aliasing. To work around this, create temporary copy
+          of @coord.
+        */
+       coord_dup(&shadow, coord);
+       result =
+           kill_node_content(coord, &shadow, NULL, NULL, NULL, NULL, NULL, 0);
+       if (result == 0) {
+               /* NOTE-NIKITA quota plugin? */
+               DQUOT_FREE_SPACE_NODIRTY(dir, length);
+       }
+       return result;
+}
+
+/* ->s.dir.max_name_len() method for this item plugin */
+int max_name_len_cde(const struct inode *dir /* directory */ )
+{
+       return
+               reiser4_tree_by_inode(dir)->nplug->max_item_size() -
+               sizeof(directory_entry_format) - sizeof(cde_item_format) -
+               sizeof(cde_unit_header) - 2;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/cde.h linux-2.6.20/fs/reiser4/plugin/item/cde.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/cde.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/cde.h   2007-05-06 14:50:43.803008220 +0400
@@ -0,0 +1,87 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Compound directory item. See cde.c for description. */
+
+#if !defined( __FS_REISER4_PLUGIN_COMPRESSED_DE_H__ )
+#define __FS_REISER4_PLUGIN_COMPRESSED_DE_H__
+
+#include "../../forward.h"
+#include "../../kassign.h"
+#include "../../dformat.h"
+
+#include <linux/fs.h>          /* for struct inode */
+#include <linux/dcache.h>      /* for struct dentry, etc  */
+
+typedef struct cde_unit_header {
+       de_id hash;
+       d16 offset;
+} cde_unit_header;
+
+typedef struct cde_item_format {
+       d16 num_of_entries;
+       cde_unit_header entry[0];
+} cde_item_format;
+
+typedef struct cde_entry {
+       const struct inode *dir;
+       const struct inode *obj;
+       const struct qstr *name;
+} cde_entry;
+
+typedef struct cde_entry_data {
+       int num_of_entries;
+       cde_entry *entry;
+} cde_entry_data;
+
+/* plugin->item.b.* */
+reiser4_key *max_key_inside_cde(const coord_t * coord, reiser4_key * result);
+int can_contain_key_cde(const coord_t * coord, const reiser4_key * key,
+                       const reiser4_item_data *);
+int mergeable_cde(const coord_t * p1, const coord_t * p2);
+pos_in_node_t nr_units_cde(const coord_t * coord);
+reiser4_key *unit_key_cde(const coord_t * coord, reiser4_key * key);
+int estimate_cde(const coord_t * coord, const reiser4_item_data * data);
+void print_cde(const char *prefix, coord_t * coord);
+int init_cde(coord_t * coord, coord_t * from, reiser4_item_data * data);
+lookup_result lookup_cde(const reiser4_key * key, lookup_bias bias,
+                        coord_t * coord);
+int paste_cde(coord_t * coord, reiser4_item_data * data,
+             carry_plugin_info * info UNUSED_ARG);
+int can_shift_cde(unsigned free_space, coord_t * coord, znode * target,
+                 shift_direction pend, unsigned *size, unsigned want);
+void copy_units_cde(coord_t * target, coord_t * source, unsigned from,
+                   unsigned count, shift_direction where_is_free_space,
+                   unsigned free_space);
+int cut_units_cde(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                 struct carry_cut_data *, reiser4_key * smallest_removed,
+                 reiser4_key * new_first);
+int kill_units_cde(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                  struct carry_kill_data *, reiser4_key * smallest_removed,
+                  reiser4_key * new_first);
+void print_cde(const char *prefix, coord_t * coord);
+int reiser4_check_cde(const coord_t * coord, const char **error);
+
+/* plugin->u.item.s.dir.* */
+int extract_key_cde(const coord_t * coord, reiser4_key * key);
+int update_key_cde(const coord_t * coord, const reiser4_key * key,
+                  lock_handle * lh);
+char *extract_name_cde(const coord_t * coord, char *buf);
+int add_entry_cde(struct inode *dir, coord_t * coord,
+                 lock_handle * lh, const struct dentry *name,
+                 reiser4_dir_entry_desc * entry);
+int rem_entry_cde(struct inode *dir, const struct qstr *name, coord_t * coord,
+                 lock_handle * lh, reiser4_dir_entry_desc * entry);
+int max_name_len_cde(const struct inode *dir);
+
+/* __FS_REISER4_PLUGIN_COMPRESSED_DE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/ctail.c linux-2.6.20/fs/reiser4/plugin/item/ctail.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/ctail.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/ctail.c 2007-05-06 14:50:43.803008220 +0400
@@ -0,0 +1,1570 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* ctails (aka "clustered tails") are items for cryptcompress objects */
+
+/* DESCRIPTION:
+
+Each cryptcompress object is stored on disk as a set of clusters sliced
+into ctails.
+
+Internal on-disk structure:
+
+        HEADER   (1)  Here stored disk cluster shift
+       BODY
+*/
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "item.h"
+#include "../node/node.h"
+#include "../plugin.h"
+#include "../object.h"
+#include "../../znode.h"
+#include "../../carry.h"
+#include "../../tree.h"
+#include "../../inode.h"
+#include "../../super.h"
+#include "../../context.h"
+#include "../../page_cache.h"
+#include "../cluster.h"
+#include "../../flush.h"
+#include "../../tree_walk.h"
+
+#include <linux/pagevec.h>
+#include <linux/swap.h>
+#include <linux/fs.h>
+
+/* return body of ctail item at @coord */
+static ctail_item_format *ctail_formatted_at(const coord_t * coord)
+{
+       assert("edward-60", coord != NULL);
+       return item_body_by_coord(coord);
+}
+
+static int cluster_shift_by_coord(const coord_t * coord)
+{
+       return get_unaligned(&ctail_formatted_at(coord)->cluster_shift);
+}
+
+static inline void dclust_set_extension_shift(hint_t * hint)
+{
+       assert("edward-1270",
+              item_id_by_coord(&hint->ext_coord.coord) == CTAIL_ID);
+       hint->ext_coord.extension.ctail.shift =
+           cluster_shift_by_coord(&hint->ext_coord.coord);
+}
+
+static loff_t off_by_coord(const coord_t * coord)
+{
+       reiser4_key key;
+       return get_key_offset(item_key_by_coord(coord, &key));
+}
+
+int coord_is_unprepped_ctail(const coord_t * coord)
+{
+       assert("edward-1233", coord != NULL);
+       assert("edward-1234", item_id_by_coord(coord) == CTAIL_ID);
+       assert("edward-1235",
+              ergo((int)cluster_shift_by_coord(coord) == (int)UCTAIL_SHIFT,
+                   nr_units_ctail(coord) == (pos_in_node_t) UCTAIL_NR_UNITS));
+
+       return (int)cluster_shift_by_coord(coord) == (int)UCTAIL_SHIFT;
+}
+
+static cloff_t clust_by_coord(const coord_t * coord, struct inode *inode)
+{
+       int shift;
+
+       if (inode != NULL) {
+               shift = inode_cluster_shift(inode);
+               assert("edward-1236",
+                      ergo(!coord_is_unprepped_ctail(coord),
+                           shift == cluster_shift_by_coord(coord)));
+       } else {
+               assert("edward-1237", !coord_is_unprepped_ctail(coord));
+               shift = cluster_shift_by_coord(coord);
+       }
+       return off_by_coord(coord) >> shift;
+}
+
+static int disk_cluster_size(const coord_t * coord)
+{
+       assert("edward-1156",
+              item_plugin_by_coord(coord) == item_plugin_by_id(CTAIL_ID));
+       /* calculation of disk cluster size
+          is meaninless if ctail is unprepped */
+       assert("edward-1238", !coord_is_unprepped_ctail(coord));
+
+       return 1 << cluster_shift_by_coord(coord);
+}
+
+/* true if the key is of first disk cluster item */
+static int is_disk_cluster_key(const reiser4_key * key, const coord_t * coord)
+{
+       assert("edward-1239", item_id_by_coord(coord) == CTAIL_ID);
+
+       return coord_is_unprepped_ctail(coord) ||
+           ((get_key_offset(key) &
+             ((loff_t) disk_cluster_size(coord) - 1)) == 0);
+}
+
+static char *first_unit(coord_t * coord)
+{
+       /* FIXME: warning: pointer of type `void *' used in arithmetic */
+       return (char *)item_body_by_coord(coord) + sizeof(ctail_item_format);
+}
+
+/* plugin->u.item.b.max_key_inside :
+   tail_max_key_inside */
+
+/* plugin->u.item.b.can_contain_key */
+int
+can_contain_key_ctail(const coord_t * coord, const reiser4_key * key,
+                     const reiser4_item_data * data)
+{
+       reiser4_key item_key;
+
+       if (item_plugin_by_coord(coord) != data->iplug)
+               return 0;
+
+       item_key_by_coord(coord, &item_key);
+       if (get_key_locality(key) != get_key_locality(&item_key) ||
+           get_key_objectid(key) != get_key_objectid(&item_key))
+               return 0;
+       if (get_key_offset(&item_key) + nr_units_ctail(coord) !=
+           get_key_offset(key))
+               return 0;
+       if (is_disk_cluster_key(key, coord))
+               return 0;
+       return 1;
+}
+
+/* plugin->u.item.b.mergeable
+   c-tails of different clusters are not mergeable */
+int mergeable_ctail(const coord_t * p1, const coord_t * p2)
+{
+       reiser4_key key1, key2;
+
+       assert("edward-62", item_id_by_coord(p1) == CTAIL_ID);
+       assert("edward-61", plugin_of_group(item_plugin_by_coord(p1),
+                                           UNIX_FILE_METADATA_ITEM_TYPE));
+
+       if (item_id_by_coord(p2) != CTAIL_ID) {
+               /* second item is of another type */
+               return 0;
+       }
+
+       item_key_by_coord(p1, &key1);
+       item_key_by_coord(p2, &key2);
+       if (get_key_locality(&key1) != get_key_locality(&key2) ||
+           get_key_objectid(&key1) != get_key_objectid(&key2) ||
+           get_key_type(&key1) != get_key_type(&key2)) {
+               /* items of different objects */
+               return 0;
+       }
+       if (get_key_offset(&key1) + nr_units_ctail(p1) != get_key_offset(&key2))
+               /*  not adjacent items */
+               return 0;
+       if (is_disk_cluster_key(&key2, p2))
+               return 0;
+       return 1;
+}
+
+/* plugin->u.item.b.nr_units */
+pos_in_node_t nr_units_ctail(const coord_t * coord)
+{
+       return (item_length_by_coord(coord) -
+               sizeof(ctail_formatted_at(coord)->cluster_shift));
+}
+
+/* plugin->u.item.b.estimate:
+   estimate how much space is needed to insert/paste @data->length bytes
+   into ctail at @coord */
+int estimate_ctail(const coord_t * coord /* coord of item */ ,
+                  const reiser4_item_data *
+                  data /* parameters for new item */ )
+{
+       if (coord == NULL)
+               /* insert */
+               return (sizeof(ctail_item_format) + data->length);
+       else
+               /* paste */
+               return data->length;
+}
+
+/* ->init() method for this item plugin. */
+int init_ctail(coord_t * to /* coord of item */ ,
+              coord_t * from /* old_item */ ,
+              reiser4_item_data * data /* structure used for insertion */ )
+{
+       int cluster_shift;      /* cpu value to convert */
+
+       if (data) {
+               assert("edward-463", data->length > sizeof(ctail_item_format));
+               cluster_shift = *((int *)(data->arg));
+               data->length -= sizeof(ctail_item_format);
+       } else {
+               assert("edward-464", from != NULL);
+               assert("edward-855", ctail_ok(from));
+               cluster_shift = (int)(cluster_shift_by_coord(from));
+       }
+       put_unaligned((d8)cluster_shift, &ctail_formatted_at(to)->cluster_shift);
+       assert("edward-856", ctail_ok(to));
+       return 0;
+}
+
+/* plugin->u.item.b.lookup:
+   NULL: We are looking for item keys only */
+
+#if REISER4_DEBUG
+int ctail_ok(const coord_t * coord)
+{
+       return coord_is_unprepped_ctail(coord) ||
+           cluster_shift_ok(cluster_shift_by_coord(coord));
+}
+
+/* plugin->u.item.b.check */
+int check_ctail(const coord_t * coord, const char **error)
+{
+       if (!ctail_ok(coord)) {
+               if (error)
+                       *error = "bad cluster shift in ctail";
+               return 1;
+       }
+       return 0;
+}
+#endif
+
+/* plugin->u.item.b.paste */
+int
+paste_ctail(coord_t * coord, reiser4_item_data * data,
+           carry_plugin_info * info UNUSED_ARG)
+{
+       unsigned old_nr_units;
+
+       assert("edward-268", data->data != NULL);
+       /* copy only from kernel space */
+       assert("edward-66", data->user == 0);
+
+       old_nr_units =
+           item_length_by_coord(coord) - sizeof(ctail_item_format) -
+           data->length;
+
+       /* ctail items never get pasted in the middle */
+
+       if (coord->unit_pos == 0 && coord->between == AT_UNIT) {
+
+               /* paste at the beginning when create new item */
+               assert("edward-450",
+                      item_length_by_coord(coord) ==
+                      data->length + sizeof(ctail_item_format));
+               assert("edward-451", old_nr_units == 0);
+       } else if (coord->unit_pos == old_nr_units - 1
+                  && coord->between == AFTER_UNIT) {
+
+               /* paste at the end */
+               coord->unit_pos++;
+       } else
+               impossible("edward-453", "bad paste position");
+
+       memcpy(first_unit(coord) + coord->unit_pos, data->data, data->length);
+
+       assert("edward-857", ctail_ok(coord));
+
+       return 0;
+}
+
+/* plugin->u.item.b.fast_paste */
+
+/* plugin->u.item.b.can_shift
+   number of units is returned via return value, number of bytes via @size. For
+   ctail items they coincide */
+int
+can_shift_ctail(unsigned free_space, coord_t * source,
+               znode * target, shift_direction direction UNUSED_ARG,
+               unsigned *size /* number of bytes */ , unsigned want)
+{
+       /* make sure that that we do not want to shift more than we have */
+       assert("edward-68", want > 0 && want <= nr_units_ctail(source));
+
+       *size = min(want, free_space);
+
+       if (!target) {
+               /* new item will be created */
+               if (*size <= sizeof(ctail_item_format)) {
+                       *size = 0;
+                       return 0;
+               }
+               return *size - sizeof(ctail_item_format);
+       }
+       return *size;
+}
+
+/* plugin->u.item.b.copy_units
+   cooperates with ->can_shift() */
+void
+copy_units_ctail(coord_t * target, coord_t * source,
+                unsigned from, unsigned count /* units */ ,
+                shift_direction where_is_free_space,
+                unsigned free_space /* bytes */ )
+{
+       /* make sure that item @target is expanded already */
+       assert("edward-69", (unsigned)item_length_by_coord(target) >= count);
+       assert("edward-70", free_space == count || free_space == count + 1);
+
+       assert("edward-858", ctail_ok(source));
+
+       if (where_is_free_space == SHIFT_LEFT) {
+               /* append item @target with @count first bytes of @source:
+                  this restriction came from ordinary tails */
+               assert("edward-71", from == 0);
+               assert("edward-860", ctail_ok(target));
+
+               memcpy(first_unit(target) + nr_units_ctail(target) - count,
+                      first_unit(source), count);
+       } else {
+               /* target item is moved to right already */
+               reiser4_key key;
+
+               assert("edward-72", nr_units_ctail(source) == from + count);
+
+               if (free_space == count) {
+                       init_ctail(target, source, NULL);
+               } else {
+                       /* new item has been created */
+                       assert("edward-862", ctail_ok(target));
+               }
+               memcpy(first_unit(target), first_unit(source) + from, count);
+
+               assert("edward-863", ctail_ok(target));
+
+               /* new units are inserted before first unit in an item,
+                  therefore, we have to update item key */
+               item_key_by_coord(source, &key);
+               set_key_offset(&key, get_key_offset(&key) + from);
+
+               node_plugin_by_node(target->node)->update_item_key(target, &key,
+                                                                  NULL /*info */);
+       }
+}
+
+/* plugin->u.item.b.create_hook */
+int create_hook_ctail(const coord_t * coord, void *arg)
+{
+       assert("edward-864", znode_is_loaded(coord->node));
+
+       znode_set_convertible(coord->node);
+       return 0;
+}
+
+/* plugin->u.item.b.kill_hook */
+int
+kill_hook_ctail(const coord_t * coord, pos_in_node_t from, pos_in_node_t count,
+               carry_kill_data * kdata)
+{
+       struct inode *inode;
+
+       assert("edward-1157", item_id_by_coord(coord) == CTAIL_ID);
+       assert("edward-291", znode_is_write_locked(coord->node));
+
+       inode = kdata->inode;
+       if (inode) {
+               reiser4_key key;
+               item_key_by_coord(coord, &key);
+
+               if (from == 0 && is_disk_cluster_key(&key, coord)) {
+                       /* disk cluster is killed */
+                       cloff_t start =
+                           off_to_clust(get_key_offset(&key), inode);
+                       truncate_page_cluster_cryptcompress(inode, start,
+                                                       kdata->params.truncate);
+                       inode_sub_bytes(inode, inode_cluster_size(inode));
+               }
+       }
+       return 0;
+}
+
+/* for shift_hook_ctail(),
+   return true if the first disk cluster item has dirty child
+*/
+static int ctail_convertible(const coord_t * coord)
+{
+       int result;
+       reiser4_key key;
+       jnode *child = NULL;
+
+       assert("edward-477", coord != NULL);
+       assert("edward-478", item_id_by_coord(coord) == CTAIL_ID);
+
+       if (coord_is_unprepped_ctail(coord))
+               /* unprepped ctail should be converted */
+               return 1;
+
+       item_key_by_coord(coord, &key);
+       child = jlookup(current_tree,
+                       get_key_objectid(&key),
+                       off_to_pg(off_by_coord(coord)));
+       if (!child)
+               return 0;
+       result = JF_ISSET(child, JNODE_DIRTY);
+       jput(child);
+       return result;
+}
+
+/* FIXME-EDWARD */
+/* plugin->u.item.b.shift_hook */
+int shift_hook_ctail(const coord_t * item /* coord of item */ ,
+                    unsigned from UNUSED_ARG /* start unit */ ,
+                    unsigned count UNUSED_ARG /* stop unit */ ,
+                    znode * old_node /* old parent */ )
+{
+       assert("edward-479", item != NULL);
+       assert("edward-480", item->node != old_node);
+
+       if (!znode_convertible(old_node) || znode_convertible(item->node))
+               return 0;
+       if (ctail_convertible(item))
+               znode_set_convertible(item->node);
+       return 0;
+}
+
+static int
+cut_or_kill_ctail_units(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                       int cut, void *p, reiser4_key * smallest_removed,
+                       reiser4_key * new_first)
+{
+       pos_in_node_t count;    /* number of units to cut */
+       char *item;
+
+       count = to - from + 1;
+       item = item_body_by_coord(coord);
+
+       assert("edward-74", ergo(from != 0, to == coord_last_unit_pos(coord)));
+
+       if (smallest_removed) {
+               /* store smallest key removed */
+               item_key_by_coord(coord, smallest_removed);
+               set_key_offset(smallest_removed,
+                              get_key_offset(smallest_removed) + from);
+       }
+
+       if (new_first) {
+               assert("vs-1531", from == 0);
+
+               item_key_by_coord(coord, new_first);
+               set_key_offset(new_first,
+                              get_key_offset(new_first) + from + count);
+       }
+
+       if (!cut)
+               kill_hook_ctail(coord, from, 0, (struct carry_kill_data *)p);
+
+       if (from == 0) {
+               if (count != nr_units_ctail(coord)) {
+                       /* part of item is removed, so move free space at the beginning
+                          of the item and update item key */
+                       reiser4_key key;
+                       memcpy(item + to + 1, item, sizeof(ctail_item_format));
+                       item_key_by_coord(coord, &key);
+                       set_key_offset(&key, get_key_offset(&key) + count);
+                       node_plugin_by_node(coord->node)->update_item_key(coord,
+                                                                         &key,
+                                                                         NULL);
+               } else {
+                       /* cut_units should not be called to cut evrything */
+                       assert("vs-1532", ergo(cut, 0));
+                       /* whole item is cut, so more then amount of space occupied
+                          by units got freed */
+                       count += sizeof(ctail_item_format);
+               }
+               if (REISER4_DEBUG)
+                       memset(item, 0, count);
+       } else if (REISER4_DEBUG)
+               memset(item + sizeof(ctail_item_format) + from, 0, count);
+       return count;
+}
+
+/* plugin->u.item.b.cut_units */
+int
+cut_units_ctail(coord_t * item, pos_in_node_t from, pos_in_node_t to,
+               carry_cut_data * cdata, reiser4_key * smallest_removed,
+               reiser4_key * new_first)
+{
+       return cut_or_kill_ctail_units(item, from, to, 1, NULL,
+                                      smallest_removed, new_first);
+}
+
+/* plugin->u.item.b.kill_units */
+int
+kill_units_ctail(coord_t * item, pos_in_node_t from, pos_in_node_t to,
+                struct carry_kill_data *kdata, reiser4_key * smallest_removed,
+                reiser4_key * new_first)
+{
+       return cut_or_kill_ctail_units(item, from, to, 0, kdata,
+                                      smallest_removed, new_first);
+}
+
+/* plugin->u.item.s.file.read */
+int read_ctail(struct file *file UNUSED_ARG, flow_t * f, hint_t * hint)
+{
+       uf_coord_t *uf_coord;
+       coord_t *coord;
+
+       uf_coord = &hint->ext_coord;
+       coord = &uf_coord->coord;
+       assert("edward-127", f->user == 0);
+       assert("edward-129", coord && coord->node);
+       assert("edward-130", coord_is_existing_unit(coord));
+       assert("edward-132", znode_is_loaded(coord->node));
+
+       /* start read only from the beginning of ctail */
+       assert("edward-133", coord->unit_pos == 0);
+       /* read only whole ctails */
+       assert("edward-135", nr_units_ctail(coord) <= f->length);
+
+       assert("edward-136", reiser4_schedulable());
+       assert("edward-886", ctail_ok(coord));
+
+       if (f->data)
+               memcpy(f->data, (char *)first_unit(coord),
+                      (size_t) nr_units_ctail(coord));
+
+       dclust_set_extension_shift(hint);
+       mark_page_accessed(znode_page(coord->node));
+       move_flow_forward(f, nr_units_ctail(coord));
+
+       return 0;
+}
+
+/* Reads a disk cluster consists of ctail items,
+   attaches a transform stream with plain text */
+int ctail_read_disk_cluster(reiser4_cluster_t * clust, struct inode *inode,
+                           znode_lock_mode mode)
+{
+       int result;
+       assert("edward-1450", mode == ZNODE_READ_LOCK || ZNODE_WRITE_LOCK);
+       assert("edward-671", clust->hint != NULL);
+       assert("edward-140", clust->dstat == INVAL_DISK_CLUSTER);
+       assert("edward-672", cryptcompress_inode_ok(inode));
+
+       /* set input stream */
+       result = grab_tfm_stream(inode, &clust->tc, INPUT_STREAM);
+       if (result)
+               return result;
+
+       result = find_disk_cluster(clust, inode, 1 /* read items */, mode);
+       assert("edward-1340", !result);
+       if (result)
+               return result;
+       if (mode == ZNODE_READ_LOCK)
+               /* write still need the lock to insert unprepped
+                  items, etc... */
+               put_hint_cluster(clust, inode, ZNODE_READ_LOCK);
+
+       if (clust->dstat == FAKE_DISK_CLUSTER ||
+           clust->dstat == UNPR_DISK_CLUSTER) {
+               tfm_cluster_set_uptodate(&clust->tc);
+               return 0;
+       }
+       result = grab_coa(&clust->tc, inode_compression_plugin(inode));
+       if (result)
+               return result;
+       result = reiser4_inflate_cluster(clust, inode);
+       if (result)
+               return result;
+       tfm_cluster_set_uptodate(&clust->tc);
+       return 0;
+}
+
+/* read one locked page */
+int do_readpage_ctail(struct inode * inode, reiser4_cluster_t * clust,
+                     struct page *page, znode_lock_mode mode)
+{
+       int ret;
+       unsigned cloff;
+       char *data;
+       size_t pgcnt;
+       tfm_cluster_t *tc = &clust->tc;
+
+       assert("edward-212", PageLocked(page));
+
+       if (PageUptodate(page))
+               goto exit;
+
+       if (!tfm_cluster_is_uptodate(&clust->tc)) {
+               clust->index = pg_to_clust(page->index, inode);
+               unlock_page(page);
+               ret = ctail_read_disk_cluster(clust, inode, mode);
+               lock_page(page);
+               if (ret)
+                       return ret;
+       }
+       if (PageUptodate(page))
+               /* races with another read/write */
+               goto exit;
+
+       /* bytes in the page */
+       pgcnt = cnt_to_pgcnt(i_size_read(inode), page->index);
+
+       if (pgcnt == 0) {
+               assert("edward-1290", 0);
+               return RETERR(-EINVAL);
+       }
+       assert("edward-119", tfm_cluster_is_uptodate(tc));
+
+       switch (clust->dstat) {
+       case UNPR_DISK_CLUSTER:
+               assert("edward-1285", 0);
+#if REISER4_DEBUG
+               warning("edward-1168",
+                       "page %lu is not uptodate and disk cluster %lu (inode %llu) is unprepped\n",
+                       page->index, clust->index,
+                       (unsigned long long)get_inode_oid(inode));
+#endif
+       case FAKE_DISK_CLUSTER:
+               /* fill the page by zeroes */
+               data = kmap_atomic(page, KM_USER0);
+
+               memset(data, 0, PAGE_CACHE_SIZE);
+               flush_dcache_page(page);
+               kunmap_atomic(data, KM_USER0);
+               SetPageUptodate(page);
+               break;
+       case PREP_DISK_CLUSTER:
+               /* fill the page by transformed data */
+               assert("edward-1058", !PageUptodate(page));
+               assert("edward-120", tc->len <= inode_cluster_size(inode));
+
+               /* start page offset in the cluster */
+               cloff = pg_to_off_to_cloff(page->index, inode);
+
+               data = kmap(page);
+               memcpy(data, tfm_stream_data(tc, OUTPUT_STREAM) + cloff, pgcnt);
+               memset(data + pgcnt, 0, (size_t) PAGE_CACHE_SIZE - pgcnt);
+               flush_dcache_page(page);
+               kunmap(page);
+               SetPageUptodate(page);
+               break;
+       default:
+               impossible("edward-1169", "bad disk cluster state");
+       }
+      exit:
+       return 0;
+}
+
+/* plugin->u.item.s.file.readpage */
+int readpage_ctail(void *vp, struct page *page)
+{
+       int result;
+       hint_t *hint;
+       reiser4_cluster_t *clust = vp;
+
+       assert("edward-114", clust != NULL);
+       assert("edward-115", PageLocked(page));
+       assert("edward-116", !PageUptodate(page));
+       assert("edward-117", !jprivate(page) && !PagePrivate(page));
+       assert("edward-118", page->mapping && page->mapping->host);
+       assert("edward-867", !tfm_cluster_is_uptodate(&clust->tc));
+
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL) {
+               unlock_page(page);
+               return RETERR(-ENOMEM);
+       }
+       clust->hint = hint;
+       result = load_file_hint(clust->file, hint);
+       if (result) {
+               kfree(hint);
+               unlock_page(page);
+               return result;
+       }
+       assert("vs-25", hint->ext_coord.lh == &hint->lh);
+       result = do_readpage_ctail(page->mapping->host, clust, page,
+                                  ZNODE_READ_LOCK);
+
+       assert("edward-213", PageLocked(page));
+       assert("edward-1163", ergo(!result, PageUptodate(page)));
+       assert("edward-868",
+              ergo(!result, tfm_cluster_is_uptodate(&clust->tc)));
+
+       unlock_page(page);
+       done_lh(&hint->lh);
+       hint->ext_coord.valid = 0;
+       save_file_hint(clust->file, hint);
+       kfree(hint);
+       tfm_cluster_clr_uptodate(&clust->tc);
+
+       return result;
+}
+
+/* Helper function for ->readpages() */
+static int
+ctail_read_page_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       int i;
+       int result;
+       assert("edward-779", clust != NULL);
+       assert("edward-1059", clust->win == NULL);
+       assert("edward-780", inode != NULL);
+
+       result = prepare_page_cluster(inode, clust, 0 /* do not capture */ );
+       if (result)
+               return result;
+       result = ctail_read_disk_cluster(clust, inode, ZNODE_READ_LOCK);
+       if (result)
+               goto out;
+       /* at this point stream with valid plain text is attached */
+       assert("edward-781", tfm_cluster_is_uptodate(&clust->tc));
+
+       for (i = 0; i < clust->nr_pages; i++) {
+               struct page *page = clust->pages[i];
+               lock_page(page);
+               result = do_readpage_ctail(inode, clust, page, ZNODE_READ_LOCK);
+               unlock_page(page);
+               if (result)
+                       break;
+       }
+       tfm_cluster_clr_uptodate(&clust->tc);
+      out:
+       reiser4_release_cluster_pages(clust);
+       return result;
+}
+
+/* filler for read_cache_pages() */
+static int ctail_readpages_filler(void * data, struct page * page)
+{
+       int ret = 0;
+       reiser4_cluster_t * clust = data;
+       struct inode * inode = clust->file->f_dentry->d_inode;
+
+       if (PageUptodate(page)) {
+               unlock_page(page);
+               return 0;
+       }
+       unlock_page(page);
+       move_cluster_forward(clust, inode, page->index);
+       ret = ctail_read_page_cluster(clust, inode);
+       if (ret)
+               return ret;
+       assert("edward-869", !tfm_cluster_is_uptodate(&clust->tc));
+
+       lock_page(page);
+       ret = do_readpage_ctail(inode, clust, page, ZNODE_READ_LOCK);
+       assert("edward-1061", ergo(!ret, PageUptodate(page)));
+       unlock_page(page);
+
+       return ret;
+}
+
+/* We populate a bit more then upper readahead suggests:
+   with each nominated page we read the whole page cluster
+   this page belongs to. */
+int readpages_ctail(struct file *file, struct address_space *mapping,
+                   struct list_head *pages)
+{
+       int ret = 0;
+       hint_t *hint;
+       reiser4_cluster_t clust;
+       struct inode *inode = mapping->host;
+
+       assert("edward-1521", inode == file->f_dentry->d_inode);
+
+       cluster_init_read(&clust, NULL);
+       clust.file = file;
+       hint = kmalloc(sizeof(*hint), reiser4_ctx_gfp_mask_get());
+       if (hint == NULL) {
+               warning("vs-28", "failed to allocate hint");
+               ret = RETERR(-ENOMEM);
+               goto exit1;
+       }
+       clust.hint = hint;
+       ret = load_file_hint(clust.file, hint);
+       if (ret) {
+               warning("edward-1522", "failed to load hint");
+               goto exit2;
+       }
+       assert("vs-26", hint->ext_coord.lh == &hint->lh);
+       ret = alloc_cluster_pgset(&clust, cluster_nrpages(inode));
+       if (ret) {
+               warning("edward-1523", "failed to alloc pgset");
+               goto exit3;
+       }
+       ret = read_cache_pages(mapping, pages, ctail_readpages_filler, &clust);
+
+       assert("edward-870", !tfm_cluster_is_uptodate(&clust.tc));
+ exit3:
+       done_lh(&hint->lh);
+       save_file_hint(file, hint);
+       hint->ext_coord.valid = 0;
+ exit2:
+       kfree(hint);
+ exit1:
+       put_cluster_handle(&clust);
+       return ret;
+}
+
+/*
+   plugin->u.item.s.file.append_key
+   key of the first item of the next disk cluster
+*/
+reiser4_key *append_key_ctail(const coord_t * coord, reiser4_key * key)
+{
+       assert("edward-1241", item_id_by_coord(coord) == CTAIL_ID);
+       assert("edward-1242", cluster_shift_ok(cluster_shift_by_coord(coord)));
+
+       item_key_by_coord(coord, key);
+       set_key_offset(key,
+                      ((__u64) (clust_by_coord(coord, NULL)) +
+                       1) << cluster_shift_by_coord(coord));
+       return key;
+}
+
+static int
+insert_unprepped_ctail(reiser4_cluster_t * clust, struct inode *inode)
+{
+       int result;
+       char buf[UCTAIL_NR_UNITS];
+       reiser4_item_data data;
+       reiser4_key key;
+       int shift = (int)UCTAIL_SHIFT;
+
+       memset(buf, 0, (size_t) UCTAIL_NR_UNITS);
+       result = key_by_inode_cryptcompress(inode,
+                                           clust_to_off(clust->index, inode),
+                                           &key);
+       if (result)
+               return result;
+       data.user = 0;
+       data.iplug = item_plugin_by_id(CTAIL_ID);
+       data.arg = &shift;
+       data.length = sizeof(ctail_item_format) + (size_t) UCTAIL_NR_UNITS;
+       data.data = buf;
+
+       result = insert_by_coord(&clust->hint->ext_coord.coord,
+                                &data, &key, clust->hint->ext_coord.lh, 0);
+       return result;
+}
+
+static int
+insert_cryptcompress_flow(coord_t * coord, lock_handle * lh, flow_t * f,
+                         struct inode *inode)
+{
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       reiser4_item_data *data;
+       carry_op *op;
+       int cluster_shift = inode_cluster_shift(inode);
+
+       pool =
+           init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                           sizeof(*data));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+       data = (reiser4_item_data *) (lowest_level + 3);
+
+       assert("edward-466", coord->between == AFTER_ITEM
+              || coord->between == AFTER_UNIT || coord->between == BEFORE_ITEM
+              || coord->between == EMPTY_NODE
+              || coord->between == BEFORE_UNIT);
+
+       if (coord->between == AFTER_UNIT) {
+               coord->unit_pos = 0;
+               coord->between = AFTER_ITEM;
+       }
+       op = reiser4_post_carry(lowest_level, COP_INSERT_FLOW, coord->node,
+                               0 /* operate directly on coord -> node */);
+       if (IS_ERR(op) || (op == NULL)) {
+               done_carry_pool(pool);
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+       }
+       data->user = 0;
+       data->iplug = item_plugin_by_id(CTAIL_ID);
+       data->arg = &cluster_shift;
+
+       data->length = 0;
+       data->data = NULL;
+
+       op->u.insert_flow.flags = COPI_DONT_SHIFT_LEFT | COPI_DONT_SHIFT_RIGHT;
+       op->u.insert_flow.insert_point = coord;
+       op->u.insert_flow.flow = f;
+       op->u.insert_flow.data = data;
+       op->u.insert_flow.new_nodes = 0;
+
+       lowest_level->track_type = CARRY_TRACK_CHANGE;
+       lowest_level->tracked = lh;
+
+       result = reiser4_carry(lowest_level, NULL);
+       done_carry_pool(pool);
+
+       return result;
+}
+
+/* Implementation of CRC_APPEND_ITEM mode of ctail conversion */
+static int insert_cryptcompress_flow_in_place(coord_t * coord,
+                                             lock_handle * lh, flow_t * f,
+                                             struct inode *inode)
+{
+       int ret;
+       coord_t pos;
+       lock_handle lock;
+
+       assert("edward-674", f->length <= inode_scaled_cluster_size(inode));
+       assert("edward-484", coord->between == AT_UNIT
+              || coord->between == AFTER_ITEM);
+       assert("edward-485", item_id_by_coord(coord) == CTAIL_ID);
+
+       coord_dup(&pos, coord);
+       pos.unit_pos = 0;
+       pos.between = AFTER_ITEM;
+
+       init_lh(&lock);
+       copy_lh(&lock, lh);
+
+       ret = insert_cryptcompress_flow(&pos, &lock, f, inode);
+       done_lh(&lock);
+       assert("edward-1347", znode_is_write_locked(lh->node));
+       assert("edward-1228", !ret);
+       return ret;
+}
+
+/* Implementation of CRC_OVERWRITE_ITEM mode of ctail conversion */
+static int overwrite_ctail(coord_t * coord, flow_t * f)
+{
+       unsigned count;
+
+       assert("edward-269", f->user == 0);
+       assert("edward-270", f->data != NULL);
+       assert("edward-271", f->length > 0);
+       assert("edward-272", coord_is_existing_unit(coord));
+       assert("edward-273", coord->unit_pos == 0);
+       assert("edward-274", znode_is_write_locked(coord->node));
+       assert("edward-275", reiser4_schedulable());
+       assert("edward-467", item_id_by_coord(coord) == CTAIL_ID);
+       assert("edward-1243", ctail_ok(coord));
+
+       count = nr_units_ctail(coord);
+
+       if (count > f->length)
+               count = f->length;
+       memcpy(first_unit(coord), f->data, count);
+       move_flow_forward(f, count);
+       coord->unit_pos += count;
+       return 0;
+}
+
+/* Implementation of CRC_CUT_ITEM mode of ctail conversion:
+   cut ctail (part or whole) starting from next unit position */
+static int cut_ctail(coord_t * coord)
+{
+       coord_t stop;
+
+       assert("edward-435", coord->between == AT_UNIT &&
+              coord->item_pos < coord_num_items(coord) &&
+              coord->unit_pos <= coord_num_units(coord));
+
+       if (coord->unit_pos == coord_num_units(coord))
+               /* nothing to cut */
+               return 0;
+       coord_dup(&stop, coord);
+       stop.unit_pos = coord_last_unit_pos(coord);
+
+       return cut_node_content(coord, &stop, NULL, NULL, NULL);
+}
+
+int
+ctail_insert_unprepped_cluster(reiser4_cluster_t * clust, struct inode *inode)
+{
+       int result;
+       assert("edward-1244", inode != NULL);
+       assert("edward-1245", clust->hint != NULL);
+       assert("edward-1246", clust->dstat == FAKE_DISK_CLUSTER);
+       assert("edward-1247", clust->reserved == 1);
+
+       result = get_disk_cluster_locked(clust, inode, ZNODE_WRITE_LOCK);
+       if (cbk_errored(result))
+               return result;
+       assert("edward-1249", result == CBK_COORD_NOTFOUND);
+       assert("edward-1250", znode_is_write_locked(clust->hint->lh.node));
+
+       assert("edward-1295",
+              clust->hint->ext_coord.lh->node ==
+              clust->hint->ext_coord.coord.node);
+
+       coord_set_between_clusters(&clust->hint->ext_coord.coord);
+
+       result = insert_unprepped_ctail(clust, inode);
+       all_grabbed2free();
+
+       assert("edward-1251", !result);
+       assert("edward-1252", cryptcompress_inode_ok(inode));
+       assert("edward-1253", znode_is_write_locked(clust->hint->lh.node));
+       assert("edward-1254",
+              reiser4_clustered_blocks(reiser4_get_current_sb()));
+       assert("edward-1255",
+              znode_convertible(clust->hint->ext_coord.coord.node));
+
+       return result;
+}
+
+static int do_convert_ctail(flush_pos_t * pos, cryptcompress_write_mode_t mode)
+{
+       int result = 0;
+       convert_item_info_t *info;
+
+       assert("edward-468", pos != NULL);
+       assert("edward-469", pos->sq != NULL);
+       assert("edward-845", item_convert_data(pos) != NULL);
+
+       info = item_convert_data(pos);
+       assert("edward-679", info->flow.data != NULL);
+
+       switch (mode) {
+       case CRC_APPEND_ITEM:
+               assert("edward-1229", info->flow.length != 0);
+               assert("edward-1256",
+                      cluster_shift_ok(cluster_shift_by_coord(&pos->coord)));
+               result =
+                   insert_cryptcompress_flow_in_place(&pos->coord,
+                                                      &pos->lock,
+                                                      &info->flow,
+                                                      info->inode);
+               break;
+       case CRC_OVERWRITE_ITEM:
+               assert("edward-1230", info->flow.length != 0);
+               overwrite_ctail(&pos->coord, &info->flow);
+               if (info->flow.length != 0)
+                       break;
+       case CRC_CUT_ITEM:
+               assert("edward-1231", info->flow.length == 0);
+               result = cut_ctail(&pos->coord);
+               break;
+       default:
+               result = RETERR(-EIO);
+               impossible("edward-244", "bad convert mode");
+       }
+       return result;
+}
+
+/* plugin->u.item.f.scan */
+int scan_ctail(flush_scan * scan)
+{
+       int result = 0;
+       struct page *page;
+       struct inode *inode;
+       jnode *node = scan->node;
+
+       assert("edward-227", scan->node != NULL);
+       assert("edward-228", jnode_is_cluster_page(scan->node));
+       assert("edward-639", znode_is_write_locked(scan->parent_lock.node));
+
+       page = jnode_page(node);
+       inode = page->mapping->host;
+
+       if (!reiser4_scanning_left(scan))
+               return result;
+       if (!ZF_ISSET(scan->parent_lock.node, JNODE_DIRTY))
+               znode_make_dirty(scan->parent_lock.node);
+
+       if (!znode_convertible(scan->parent_lock.node)) {
+               if (JF_ISSET(scan->node, JNODE_DIRTY))
+                       znode_set_convertible(scan->parent_lock.node);
+               else {
+                       warning("edward-681",
+                               "cluster page is already processed");
+                       return -EAGAIN;
+               }
+       }
+       return result;
+}
+
+/* If true, this function attaches children */
+static int should_attach_convert_idata(flush_pos_t * pos)
+{
+       int result;
+       assert("edward-431", pos != NULL);
+       assert("edward-432", pos->child == NULL);
+       assert("edward-619", znode_is_write_locked(pos->coord.node));
+       assert("edward-470",
+              item_plugin_by_coord(&pos->coord) ==
+              item_plugin_by_id(CTAIL_ID));
+
+       /* check for leftmost child */
+       utmost_child_ctail(&pos->coord, LEFT_SIDE, &pos->child);
+
+       if (!pos->child)
+               return 0;
+       spin_lock_jnode(pos->child);
+       result = (JF_ISSET(pos->child, JNODE_DIRTY) &&
+                 pos->child->atom == ZJNODE(pos->coord.node)->atom);
+       spin_unlock_jnode(pos->child);
+       if (!result && pos->child) {
+               /* existing child isn't to attach, clear up this one */
+               jput(pos->child);
+               pos->child = NULL;
+       }
+       return result;
+}
+
+/* plugin->init_convert_data() */
+static int
+init_convert_data_ctail(convert_item_info_t * idata, struct inode *inode)
+{
+       assert("edward-813", idata != NULL);
+       assert("edward-814", inode != NULL);
+
+       idata->inode = inode;
+       idata->d_cur = DC_FIRST_ITEM;
+       idata->d_next = DC_INVALID_STATE;
+
+       return 0;
+}
+
+static int alloc_item_convert_data(convert_info_t * sq)
+{
+       assert("edward-816", sq != NULL);
+       assert("edward-817", sq->itm == NULL);
+
+       sq->itm = kmalloc(sizeof(*sq->itm), reiser4_ctx_gfp_mask_get());
+       if (sq->itm == NULL)
+               return RETERR(-ENOMEM);
+       return 0;
+}
+
+static void free_item_convert_data(convert_info_t * sq)
+{
+       assert("edward-818", sq != NULL);
+       assert("edward-819", sq->itm != NULL);
+       assert("edward-820", sq->iplug != NULL);
+
+       kfree(sq->itm);
+       sq->itm = NULL;
+       return;
+}
+
+static int alloc_convert_data(flush_pos_t * pos)
+{
+       assert("edward-821", pos != NULL);
+       assert("edward-822", pos->sq == NULL);
+
+       pos->sq = kmalloc(sizeof(*pos->sq), reiser4_ctx_gfp_mask_get());
+       if (!pos->sq)
+               return RETERR(-ENOMEM);
+       memset(pos->sq, 0, sizeof(*pos->sq));
+       cluster_init_write(&pos->sq->clust, 0);
+       return 0;
+}
+
+void free_convert_data(flush_pos_t * pos)
+{
+       convert_info_t *sq;
+
+       assert("edward-823", pos != NULL);
+       assert("edward-824", pos->sq != NULL);
+
+       sq = pos->sq;
+       if (sq->itm)
+               free_item_convert_data(sq);
+       put_cluster_handle(&sq->clust);
+       kfree(pos->sq);
+       pos->sq = NULL;
+       return;
+}
+
+static int init_item_convert_data(flush_pos_t * pos, struct inode *inode)
+{
+       convert_info_t *sq;
+
+       assert("edward-825", pos != NULL);
+       assert("edward-826", pos->sq != NULL);
+       assert("edward-827", item_convert_data(pos) != NULL);
+       assert("edward-828", inode != NULL);
+
+       sq = pos->sq;
+
+       memset(sq->itm, 0, sizeof(*sq->itm));
+
+       /* iplug->init_convert_data() */
+       return init_convert_data_ctail(sq->itm, inode);
+}
+
+/* create and attach disk cluster info used by 'convert' phase of the flush
+   squalloc() */
+static int attach_convert_idata(flush_pos_t * pos, struct inode *inode)
+{
+       int ret = 0;
+       convert_item_info_t *info;
+       reiser4_cluster_t *clust;
+       file_plugin *fplug = inode_file_plugin(inode);
+       compression_plugin *cplug = inode_compression_plugin(inode);
+
+       assert("edward-248", pos != NULL);
+       assert("edward-249", pos->child != NULL);
+       assert("edward-251", inode != NULL);
+       assert("edward-682", cryptcompress_inode_ok(inode));
+       assert("edward-252",
+              fplug == file_plugin_by_id(CRYPTCOMPRESS_FILE_PLUGIN_ID));
+       assert("edward-473",
+              item_plugin_by_coord(&pos->coord) ==
+              item_plugin_by_id(CTAIL_ID));
+
+       if (!pos->sq) {
+               ret = alloc_convert_data(pos);
+               if (ret)
+                       return ret;
+       }
+       clust = &pos->sq->clust;
+       ret = grab_coa(&clust->tc, cplug);
+       if (ret)
+               goto err;
+       ret = set_cluster_by_page(clust,
+                                 jnode_page(pos->child),
+                                 MAX_CLUSTER_NRPAGES);
+       if (ret)
+               goto err;
+
+       assert("edward-829", pos->sq != NULL);
+       assert("edward-250", item_convert_data(pos) == NULL);
+
+       pos->sq->iplug = item_plugin_by_id(CTAIL_ID);
+
+       ret = alloc_item_convert_data(pos->sq);
+       if (ret)
+               goto err;
+       ret = init_item_convert_data(pos, inode);
+       if (ret)
+               goto err;
+       info = item_convert_data(pos);
+
+       ret = flush_cluster_pages(clust, pos->child, inode);
+       if (ret)
+               goto err;
+
+       reiser4_deflate_cluster(clust, inode);
+       inc_item_convert_count(pos);
+
+       /* make flow by transformed stream */
+       fplug->flow_by_inode(info->inode,
+                            (const char __user *)tfm_stream_data(&clust->tc, OUTPUT_STREAM),
+                            0 /* kernel space */ ,
+                            clust->tc.len,
+                            clust_to_off(clust->index, inode),
+                            WRITE_OP, &info->flow);
+       jput(pos->child);
+
+       assert("edward-683", cryptcompress_inode_ok(inode));
+       return 0;
+      err:
+       jput(pos->child);
+       free_convert_data(pos);
+       return ret;
+}
+
+/* clear up disk cluster info */
+static void detach_convert_idata(convert_info_t * sq)
+{
+       convert_item_info_t *info;
+
+       assert("edward-253", sq != NULL);
+       assert("edward-840", sq->itm != NULL);
+
+       info = sq->itm;
+       assert("edward-255", info->inode != NULL);
+       assert("edward-1212", info->flow.length == 0);
+
+       free_item_convert_data(sq);
+       return;
+}
+
+/* plugin->u.item.f.utmost_child */
+
+/* This function sets leftmost child for a first cluster item,
+   if the child exists, and NULL in other cases.
+   NOTE-EDWARD: Do not call this for RIGHT_SIDE */
+
+int utmost_child_ctail(const coord_t * coord, sideof side, jnode ** child)
+{
+       reiser4_key key;
+
+       item_key_by_coord(coord, &key);
+
+       assert("edward-257", coord != NULL);
+       assert("edward-258", child != NULL);
+       assert("edward-259", side == LEFT_SIDE);
+       assert("edward-260",
+              item_plugin_by_coord(coord) == item_plugin_by_id(CTAIL_ID));
+
+       if (!is_disk_cluster_key(&key, coord))
+               *child = NULL;
+       else
+               *child = jlookup(current_tree,
+                                get_key_objectid(item_key_by_coord
+                                                 (coord, &key)),
+                                off_to_pg(get_key_offset(&key)));
+       return 0;
+}
+
+/* Returns true if @p2 is the next item to @p1
+   in the _same_ disk cluster.
+   Disk cluster is a set of items. If ->clustered() != NULL,
+   with each item the whole disk cluster should be read/modified
+*/
+static int clustered_ctail(const coord_t * p1, const coord_t * p2)
+{
+       return mergeable_ctail(p1, p2);
+}
+
+/* Go rightward and check for next disk cluster item, set
+   d_next to DC_CHAINED_ITEM, if the last one exists.
+   If the current position is last item, go to right neighbor.
+   Skip empty nodes. Note, that right neighbors may be not in
+   the slum because of races. If so, make it dirty and
+   convertible.
+*/
+static int next_item_dc_stat(flush_pos_t * pos)
+{
+       int ret = 0;
+       int stop = 0;
+       znode *cur;
+       coord_t coord;
+       lock_handle lh;
+       lock_handle right_lock;
+
+       assert("edward-1232", !node_is_empty(pos->coord.node));
+       assert("edward-1014",
+              pos->coord.item_pos < coord_num_items(&pos->coord));
+       assert("edward-1015", chaining_data_present(pos));
+       assert("edward-1017",
+              item_convert_data(pos)->d_next == DC_INVALID_STATE);
+
+       item_convert_data(pos)->d_next = DC_AFTER_CLUSTER;
+
+       if (item_convert_data(pos)->d_cur == DC_AFTER_CLUSTER)
+               return ret;
+       if (pos->coord.item_pos < coord_num_items(&pos->coord) - 1)
+               return ret;
+
+       /* check next slum item */
+       init_lh(&right_lock);
+       cur = pos->coord.node;
+
+       while (!stop) {
+               init_lh(&lh);
+               ret = reiser4_get_right_neighbor(&lh,
+                                                cur,
+                                                ZNODE_WRITE_LOCK,
+                                                GN_CAN_USE_UPPER_LEVELS);
+               if (ret)
+                       break;
+               ret = zload(lh.node);
+               if (ret) {
+                       done_lh(&lh);
+                       break;
+               }
+               coord_init_before_first_item(&coord, lh.node);
+
+               if (node_is_empty(lh.node)) {
+                       znode_make_dirty(lh.node);
+                       znode_set_convertible(lh.node);
+                       stop = 0;
+               } else if (clustered_ctail(&pos->coord, &coord)) {
+
+                       item_convert_data(pos)->d_next = DC_CHAINED_ITEM;
+
+                       if (!ZF_ISSET(lh.node, JNODE_DIRTY)) {
+                               /*
+                                  warning("edward-1024",
+                                  "next slum item mergeable, "
+                                  "but znode %p isn't dirty\n",
+                                  lh.node);
+                                */
+                               znode_make_dirty(lh.node);
+                       }
+                       if (!znode_convertible(lh.node)) {
+                               /*
+                                  warning("edward-1272",
+                                  "next slum item mergeable, "
+                                  "but znode %p isn't convertible\n",
+                                  lh.node);
+                                */
+                               znode_set_convertible(lh.node);
+                       }
+                       stop = 1;
+               } else
+                       stop = 1;
+               zrelse(lh.node);
+               done_lh(&right_lock);
+               copy_lh(&right_lock, &lh);
+               done_lh(&lh);
+               cur = right_lock.node;
+       }
+       done_lh(&right_lock);
+
+       if (ret == -E_NO_NEIGHBOR)
+               ret = 0;
+       return ret;
+}
+
+static int
+assign_convert_mode(convert_item_info_t * idata,
+                   cryptcompress_write_mode_t * mode)
+{
+       int result = 0;
+
+       assert("edward-1025", idata != NULL);
+
+       if (idata->flow.length) {
+               /* append or overwrite */
+               switch (idata->d_cur) {
+               case DC_FIRST_ITEM:
+               case DC_CHAINED_ITEM:
+                       *mode = CRC_OVERWRITE_ITEM;
+                       break;
+               case DC_AFTER_CLUSTER:
+                       *mode = CRC_APPEND_ITEM;
+                       break;
+               default:
+                       impossible("edward-1018", "wrong current item state");
+               }
+       } else {
+               /* cut or invalidate */
+               switch (idata->d_cur) {
+               case DC_FIRST_ITEM:
+               case DC_CHAINED_ITEM:
+                       *mode = CRC_CUT_ITEM;
+                       break;
+               case DC_AFTER_CLUSTER:
+                       result = 1;
+                       break;
+               default:
+                       impossible("edward-1019", "wrong current item state");
+               }
+       }
+       return result;
+}
+
+/* plugin->u.item.f.convert */
+/* write ctail in guessed mode */
+int convert_ctail(flush_pos_t * pos)
+{
+       int result;
+       int nr_items;
+       cryptcompress_write_mode_t mode = CRC_OVERWRITE_ITEM;
+
+       assert("edward-1020", pos != NULL);
+       assert("edward-1213", coord_num_items(&pos->coord) != 0);
+       assert("edward-1257", item_id_by_coord(&pos->coord) == CTAIL_ID);
+       assert("edward-1258", ctail_ok(&pos->coord));
+       assert("edward-261", pos->coord.node != NULL);
+
+       nr_items = coord_num_items(&pos->coord);
+       if (!chaining_data_present(pos)) {
+               if (should_attach_convert_idata(pos)) {
+                       /* attach convert item info */
+                       struct inode *inode;
+
+                       assert("edward-264", pos->child != NULL);
+                       assert("edward-265", jnode_page(pos->child) != NULL);
+                       assert("edward-266",
+                              jnode_page(pos->child)->mapping != NULL);
+
+                       inode = jnode_page(pos->child)->mapping->host;
+
+                       assert("edward-267", inode != NULL);
+
+                       /* attach item convert info by child and put the last one */
+                       result = attach_convert_idata(pos, inode);
+                       pos->child = NULL;
+                       if (result == -E_REPEAT) {
+                               /* jnode became clean, or there is no dirty
+                                  pages (nothing to update in disk cluster) */
+                               warning("edward-1021",
+                                       "convert_ctail: nothing to attach");
+                               return 0;
+                       }
+                       if (result != 0)
+                               return result;
+               } else
+                       /* unconvertible */
+                       return 0;
+       } else {
+               /* use old convert info */
+
+               convert_item_info_t *idata;
+
+               idata = item_convert_data(pos);
+
+               result = assign_convert_mode(idata, &mode);
+               if (result) {
+                       /* disk cluster is over,
+                          nothing to update anymore */
+                       detach_convert_idata(pos->sq);
+                       return 0;
+               }
+       }
+
+       assert("edward-433", chaining_data_present(pos));
+       assert("edward-1022",
+              pos->coord.item_pos < coord_num_items(&pos->coord));
+
+       result = next_item_dc_stat(pos);
+       if (result) {
+               detach_convert_idata(pos->sq);
+               return result;
+       }
+       result = do_convert_ctail(pos, mode);
+       if (result) {
+               detach_convert_idata(pos->sq);
+               return result;
+       }
+       switch (mode) {
+       case CRC_CUT_ITEM:
+               assert("edward-1214", item_convert_data(pos)->flow.length == 0);
+               assert("edward-1215",
+                      coord_num_items(&pos->coord) == nr_items ||
+                      coord_num_items(&pos->coord) == nr_items - 1);
+               if (item_convert_data(pos)->d_next == DC_CHAINED_ITEM)
+                       break;
+               if (coord_num_items(&pos->coord) != nr_items) {
+                       /* the item was killed, no more chained items */
+                       detach_convert_idata(pos->sq);
+                       if (!node_is_empty(pos->coord.node))
+                               /* make sure the next item will be scanned */
+                               coord_init_before_item(&pos->coord);
+                       break;
+               }
+       case CRC_APPEND_ITEM:
+               assert("edward-434", item_convert_data(pos)->flow.length == 0);
+               detach_convert_idata(pos->sq);
+               break;
+       case CRC_OVERWRITE_ITEM:
+               if (coord_is_unprepped_ctail(&pos->coord)) {
+                       /* convert unpprepped ctail to prepped one */
+                       int shift;
+                       shift =
+                           inode_cluster_shift(item_convert_data(pos)->inode);
+                       assert("edward-1259", cluster_shift_ok(shift));
+                       put_unaligned((d8)shift,
+                               &ctail_formatted_at(&pos->coord)->
+                               cluster_shift);
+               }
+               break;
+       }
+       return result;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/ctail.h linux-2.6.20/fs/reiser4/plugin/item/ctail.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/ctail.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/ctail.h 2007-05-06 14:50:43.803008220 +0400
@@ -0,0 +1,97 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined( __FS_REISER4_CTAIL_H__ )
+#define __FS_REISER4_CTAIL_H__
+
+/* Disk format of ctail item */
+typedef struct ctail_item_format {
+       /* packed shift; size of (prepped) disk cluster
+          is calculated as (1 << cluster_shift) */
+       d8 cluster_shift;
+       /* ctail body */
+       d8 body[0];
+} __attribute__ ((packed)) ctail_item_format;
+
+/* Unprepped disk cluster is represented by a single ctail item
+   with the following "magic" attributes: */
+/* "magic" cluster_shift */
+#define UCTAIL_SHIFT 0xff
+/* How many units unprepped ctail item has */
+#define UCTAIL_NR_UNITS 1
+
+/* The following is a set of various item states in a disk cluster.
+   Disk cluster is a set of items whose keys belong to the interval
+   [dc_key , dc_key + disk_cluster_size - 1] */
+typedef enum {
+       DC_INVALID_STATE = 0,
+       DC_FIRST_ITEM = 1,
+       DC_CHAINED_ITEM = 2,
+       DC_AFTER_CLUSTER = 3
+} dc_item_stat;
+
+/* ctail-specific extension.
+   In particular this describes parameters of disk cluster an item belongs to */
+typedef struct {
+       int shift; /* this contains cluster_shift extracted from
+                     ctail_item_format (above), or UCTAIL_SHIFT
+                     (the last one is the "magic" of unprepped disk clusters)*/
+       int dsize; /* size of a prepped disk cluster */
+       int ncount; /* count of nodes occupied by a disk cluster */
+} ctail_coord_extension_t;
+
+struct cut_list;
+
+/* plugin->item.b.* */
+int can_contain_key_ctail(const coord_t *, const reiser4_key *,
+                         const reiser4_item_data *);
+int mergeable_ctail(const coord_t * p1, const coord_t * p2);
+pos_in_node_t nr_units_ctail(const coord_t * coord);
+int estimate_ctail(const coord_t * coord, const reiser4_item_data * data);
+void print_ctail(const char *prefix, coord_t * coord);
+lookup_result lookup_ctail(const reiser4_key *, lookup_bias, coord_t *);
+
+int paste_ctail(coord_t * coord, reiser4_item_data * data,
+               carry_plugin_info * info UNUSED_ARG);
+int init_ctail(coord_t *, coord_t *, reiser4_item_data *);
+int can_shift_ctail(unsigned free_space, coord_t * coord,
+                   znode * target, shift_direction pend, unsigned *size,
+                   unsigned want);
+void copy_units_ctail(coord_t * target, coord_t * source, unsigned from,
+                     unsigned count, shift_direction where_is_free_space,
+                     unsigned free_space);
+int cut_units_ctail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                   carry_cut_data *, reiser4_key * smallest_removed,
+                   reiser4_key * new_first);
+int kill_units_ctail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                    carry_kill_data *, reiser4_key * smallest_removed,
+                    reiser4_key * new_first);
+int ctail_ok(const coord_t * coord);
+int check_ctail(const coord_t * coord, const char **error);
+
+/* plugin->u.item.s.* */
+int read_ctail(struct file *, flow_t *, hint_t *);
+int readpage_ctail(void *, struct page *);
+int readpages_ctail(struct file *, struct address_space *, struct list_head *);
+reiser4_key *append_key_ctail(const coord_t *, reiser4_key *);
+int create_hook_ctail(const coord_t * coord, void *arg);
+int kill_hook_ctail(const coord_t *, pos_in_node_t, pos_in_node_t,
+                   carry_kill_data *);
+int shift_hook_ctail(const coord_t *, unsigned, unsigned, znode *);
+
+/* plugin->u.item.f */
+int utmost_child_ctail(const coord_t *, sideof, jnode **);
+int scan_ctail(flush_scan *);
+int convert_ctail(flush_pos_t *);
+size_t inode_scaled_cluster_size(struct inode *);
+
+#endif                         /* __FS_REISER4_CTAIL_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/extent.c linux-2.6.20/fs/reiser4/plugin/item/extent.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/extent.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/extent.c        2007-05-06 14:50:43.807009470 +0400
@@ -0,0 +1,197 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "item.h"
+#include "../../key.h"
+#include "../../super.h"
+#include "../../carry.h"
+#include "../../inode.h"
+#include "../../page_cache.h"
+#include "../../flush.h"
+#include "../object.h"
+
+/* prepare structure reiser4_item_data. It is used to put one extent unit into tree */
+/* Audited by: green(2002.06.13) */
+reiser4_item_data *init_new_extent(reiser4_item_data * data, void *ext_unit,
+                                  int nr_extents)
+{
+       data->data = ext_unit;
+       /* data->data is kernel space */
+       data->user = 0;
+       data->length = sizeof(reiser4_extent) * nr_extents;
+       data->arg = NULL;
+       data->iplug = item_plugin_by_id(EXTENT_POINTER_ID);
+       return data;
+}
+
+/* how many bytes are addressed by @nr first extents of the extent item */
+reiser4_block_nr reiser4_extent_size(const coord_t * coord, pos_in_node_t nr)
+{
+       pos_in_node_t i;
+       reiser4_block_nr blocks;
+       reiser4_extent *ext;
+
+       ext = item_body_by_coord(coord);
+       assert("vs-263", nr <= nr_units_extent(coord));
+
+       blocks = 0;
+       for (i = 0; i < nr; i++, ext++) {
+               blocks += extent_get_width(ext);
+       }
+
+       return blocks * current_blocksize;
+}
+
+extent_state state_of_extent(reiser4_extent * ext)
+{
+       switch ((int)extent_get_start(ext)) {
+       case 0:
+               return HOLE_EXTENT;
+       case 1:
+               return UNALLOCATED_EXTENT;
+       default:
+               break;
+       }
+       return ALLOCATED_EXTENT;
+}
+
+int extent_is_unallocated(const coord_t * item)
+{
+       assert("jmacd-5133", item_is_extent(item));
+
+       return state_of_extent(extent_by_coord(item)) == UNALLOCATED_EXTENT;
+}
+
+/* set extent's start and width */
+void reiser4_set_extent(reiser4_extent * ext, reiser4_block_nr start,
+                       reiser4_block_nr width)
+{
+       extent_set_start(ext, start);
+       extent_set_width(ext, width);
+}
+
+/**
+ * reiser4_replace_extent - replace extent and paste 1 or 2 after it
+ * @un_extent: coordinate of extent to be overwritten
+ * @lh: need better comment
+ * @key: need better comment
+ * @exts_to_add: data prepared for insertion into tree
+ * @replace: need better comment
+ * @flags: need better comment
+ * @return_insert_position: need better comment
+ *
+ * Overwrites one extent, pastes 1 or 2 more ones after overwritten one.  If
+ * @return_inserted_position is 1 - @un_extent and @lh are returned set to
+ * first of newly inserted units, if it is 0 - @un_extent and @lh are returned
+ * set to extent which was overwritten.
+ */
+int reiser4_replace_extent(struct replace_handle *h,
+                          int return_inserted_position)
+{
+       int result;
+       znode *orig_znode;
+       /*ON_DEBUG(reiser4_extent orig_ext);*/  /* this is for debugging */
+
+       assert("vs-990", coord_is_existing_unit(h->coord));
+       assert("vs-1375", znode_is_write_locked(h->coord->node));
+       assert("vs-1426", extent_get_width(&h->overwrite) != 0);
+       assert("vs-1427", extent_get_width(&h->new_extents[0]) != 0);
+       assert("vs-1427", ergo(h->nr_new_extents == 2,
+                              extent_get_width(&h->new_extents[1]) != 0));
+
+       /* compose structure for paste */
+       init_new_extent(&h->item, &h->new_extents[0], h->nr_new_extents);
+
+       coord_dup(&h->coord_after, h->coord);
+       init_lh(&h->lh_after);
+       copy_lh(&h->lh_after, h->lh);
+       reiser4_tap_init(&h->watch, &h->coord_after, &h->lh_after, ZNODE_WRITE_LOCK);
+       reiser4_tap_monitor(&h->watch);
+
+       ON_DEBUG(h->orig_ext = *extent_by_coord(h->coord));
+       orig_znode = h->coord->node;
+
+#if REISER4_DEBUG
+       /* make sure that key is set properly */
+       unit_key_by_coord(h->coord, &h->tmp);
+       set_key_offset(&h->tmp,
+                      get_key_offset(&h->tmp) +
+                      extent_get_width(&h->overwrite) * current_blocksize);
+       assert("vs-1080", keyeq(&h->tmp, &h->paste_key));
+#endif
+
+       /* set insert point after unit to be replaced */
+       h->coord->between = AFTER_UNIT;
+
+       result = insert_into_item(h->coord, return_inserted_position ? h->lh : NULL,
+                                 &h->paste_key, &h->item, h->flags);
+       if (!result) {
+               /* now we have to replace the unit after which new units were
+                  inserted. Its position is tracked by @watch */
+               reiser4_extent *ext;
+               znode *node;
+
+               node = h->coord_after.node;
+               if (node != orig_znode) {
+                       coord_clear_iplug(&h->coord_after);
+                       result = zload(node);
+               }
+
+               if (likely(!result)) {
+                       ext = extent_by_coord(&h->coord_after);
+
+                       assert("vs-987", znode_is_loaded(node));
+                       assert("vs-988", !memcmp(ext, &h->orig_ext, sizeof(*ext)));
+
+                       /* overwrite extent unit */
+                       memcpy(ext, &h->overwrite, sizeof(reiser4_extent));
+                       znode_make_dirty(node);
+
+                       if (node != orig_znode)
+                               zrelse(node);
+
+                       if (return_inserted_position == 0) {
+                               /* coord and lh are to be set to overwritten
+                                  extent */
+                               assert("vs-1662",
+                                      WITH_DATA(node, !memcmp(&h->overwrite,
+                                                              extent_by_coord(
+                                                                      &h->coord_after),
+                                                              sizeof(reiser4_extent))));
+
+                               *h->coord = h->coord_after;
+                               done_lh(h->lh);
+                               copy_lh(h->lh, &h->lh_after);
+                       } else {
+                               /* h->coord and h->lh are to be set to first of
+                                  inserted units */
+                               assert("vs-1663",
+                                      WITH_DATA(h->coord->node,
+                                                !memcmp(&h->new_extents[0],
+                                                        extent_by_coord(h->coord),
+                                                        sizeof(reiser4_extent))));
+                               assert("vs-1664", h->lh->node == h->coord->node);
+                       }
+               }
+       }
+       reiser4_tap_done(&h->watch);
+
+       return result;
+}
+
+lock_handle *znode_lh(znode *node)
+{
+       assert("vs-1371", znode_is_write_locked(node));
+       assert("vs-1372", znode_is_wlocked_once(node));
+       return list_entry(node->lock.owners.next, lock_handle, owners_link);
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/extent_file_ops.c linux-2.6.20/fs/reiser4/plugin/item/extent_file_ops.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/extent_file_ops.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/extent_file_ops.c       2007-05-06 14:50:43.807009470 +0400
@@ -0,0 +1,1443 @@
+/* COPYRIGHT 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "item.h"
+#include "../../inode.h"
+#include "../../page_cache.h"
+#include "../object.h"
+
+#include <linux/quotaops.h>
+#include <linux/swap.h>
+#include "../../../../mm/filemap.h"
+
+static inline reiser4_extent *ext_by_offset(const znode *node, int offset)
+{
+       reiser4_extent *ext;
+
+       ext = (reiser4_extent *) (zdata(node) + offset);
+       return ext;
+}
+
+/**
+ * check_uf_coord - verify coord extension
+ * @uf_coord:
+ * @key:
+ *
+ * Makes sure that all fields of @uf_coord are set properly. If @key is
+ * specified - check whether @uf_coord is set correspondingly.
+ */
+static void check_uf_coord(const uf_coord_t *uf_coord, const reiser4_key *key)
+{
+#if REISER4_DEBUG
+       const coord_t *coord;
+       const extent_coord_extension_t *ext_coord;
+       reiser4_extent *ext;
+
+       coord = &uf_coord->coord;
+       ext_coord = &uf_coord->extension.extent;
+       ext = ext_by_offset(coord->node, uf_coord->extension.extent.ext_offset);
+
+       assert("",
+              WITH_DATA(coord->node,
+                        (uf_coord->valid == 1 &&
+                         coord_is_iplug_set(coord) &&
+                         item_is_extent(coord) &&
+                         ext_coord->nr_units == nr_units_extent(coord) &&
+                         ext == extent_by_coord(coord) &&
+                         ext_coord->width == extent_get_width(ext) &&
+                         coord->unit_pos < ext_coord->nr_units &&
+                         ext_coord->pos_in_unit < ext_coord->width &&
+                         memcmp(ext, &ext_coord->extent,
+                                sizeof(reiser4_extent)) == 0)));
+       if (key) {
+               reiser4_key coord_key;
+
+               unit_key_by_coord(&uf_coord->coord, &coord_key);
+               set_key_offset(&coord_key,
+                              get_key_offset(&coord_key) +
+                              (uf_coord->extension.extent.
+                               pos_in_unit << PAGE_CACHE_SHIFT));
+               assert("", keyeq(key, &coord_key));
+       }
+#endif
+}
+
+static inline reiser4_extent *ext_by_ext_coord(const uf_coord_t *uf_coord)
+{
+       check_uf_coord(uf_coord, NULL);
+
+       return ext_by_offset(uf_coord->coord.node,
+                            uf_coord->extension.extent.ext_offset);
+}
+
+#if REISER4_DEBUG
+
+/**
+ * offset_is_in_unit
+ *
+ *
+ *
+ */
+/* return 1 if offset @off is inside of extent unit pointed to by @coord. Set
+   pos_in_unit inside of unit correspondingly */
+static int offset_is_in_unit(const coord_t *coord, loff_t off)
+{
+       reiser4_key unit_key;
+       __u64 unit_off;
+       reiser4_extent *ext;
+
+       ext = extent_by_coord(coord);
+
+       unit_key_extent(coord, &unit_key);
+       unit_off = get_key_offset(&unit_key);
+       if (off < unit_off)
+               return 0;
+       if (off >= (unit_off + (current_blocksize * extent_get_width(ext))))
+               return 0;
+       return 1;
+}
+
+static int
+coord_matches_key_extent(const coord_t * coord, const reiser4_key * key)
+{
+       reiser4_key item_key;
+
+       assert("vs-771", coord_is_existing_unit(coord));
+       assert("vs-1258", keylt(key, append_key_extent(coord, &item_key)));
+       assert("vs-1259", keyge(key, item_key_by_coord(coord, &item_key)));
+
+       return offset_is_in_unit(coord, get_key_offset(key));
+}
+
+#endif
+
+/**
+ * can_append -
+ * @key:
+ * @coord:
+ *
+ * Returns 1 if @key is equal to an append key of item @coord is set to
+ */
+static int can_append(const reiser4_key *key, const coord_t *coord)
+{
+       reiser4_key append_key;
+
+       return keyeq(key, append_key_extent(coord, &append_key));
+}
+
+/**
+ * append_hole
+ * @coord:
+ * @lh:
+ * @key:
+ *
+ */
+static int append_hole(coord_t *coord, lock_handle *lh,
+                      const reiser4_key *key)
+{
+       reiser4_key append_key;
+       reiser4_block_nr hole_width;
+       reiser4_extent *ext, new_ext;
+       reiser4_item_data idata;
+
+       /* last item of file may have to be appended with hole */
+       assert("vs-708", znode_get_level(coord->node) == TWIG_LEVEL);
+       assert("vs-714", item_id_by_coord(coord) == EXTENT_POINTER_ID);
+
+       /* key of first byte which is not addressed by this extent */
+       append_key_extent(coord, &append_key);
+
+       assert("", keyle(&append_key, key));
+
+       /*
+        * extent item has to be appended with hole. Calculate length of that
+        * hole
+        */
+       hole_width = ((get_key_offset(key) - get_key_offset(&append_key) +
+                      current_blocksize - 1) >> current_blocksize_bits);
+       assert("vs-954", hole_width > 0);
+
+       /* set coord after last unit */
+       coord_init_after_item_end(coord);
+
+       /* get last extent in the item */
+       ext = extent_by_coord(coord);
+       if (state_of_extent(ext) == HOLE_EXTENT) {
+               /*
+                * last extent of a file is hole extent. Widen that extent by
+                * @hole_width blocks. Note that we do not worry about
+                * overflowing - extent width is 64 bits
+                */
+               reiser4_set_extent(ext, HOLE_EXTENT_START,
+                                  extent_get_width(ext) + hole_width);
+               znode_make_dirty(coord->node);
+               return 0;
+       }
+
+       /* append last item of the file with hole extent unit */
+       assert("vs-713", (state_of_extent(ext) == ALLOCATED_EXTENT ||
+                         state_of_extent(ext) == UNALLOCATED_EXTENT));
+
+       reiser4_set_extent(&new_ext, HOLE_EXTENT_START, hole_width);
+       init_new_extent(&idata, &new_ext, 1);
+       return insert_into_item(coord, lh, &append_key, &idata, 0);
+}
+
+/**
+ * check_jnodes
+ * @twig: longterm locked twig node
+ * @key:
+ *
+ */
+static void check_jnodes(znode *twig, const reiser4_key *key, int count)
+{
+#if REISER4_DEBUG
+       coord_t c;
+       reiser4_key node_key, jnode_key;
+
+       jnode_key = *key;
+
+       assert("", twig != NULL);
+       assert("", znode_get_level(twig) == TWIG_LEVEL);
+       assert("", znode_is_write_locked(twig));
+
+       zload(twig);
+       /* get the smallest key in twig node */
+       coord_init_first_unit(&c, twig);
+       unit_key_by_coord(&c, &node_key);
+       assert("", keyle(&node_key, &jnode_key));
+
+       coord_init_last_unit(&c, twig);
+       unit_key_by_coord(&c, &node_key);
+       if (item_plugin_by_coord(&c)->s.file.append_key)
+               item_plugin_by_coord(&c)->s.file.append_key(&c, &node_key);
+       set_key_offset(&jnode_key,
+                      get_key_offset(&jnode_key) + (loff_t)count * PAGE_CACHE_SIZE - 1);
+       assert("", keylt(&jnode_key, &node_key));
+       zrelse(twig);
+#endif
+}
+
+/**
+ * append_last_extent - append last file item
+ * @uf_coord: coord to start insertion from
+ * @jnodes: array of jnodes
+ * @count: number of jnodes in the array
+ *
+ * There is already at least one extent item of file @inode in the tree. Append
+ * the last of them with unallocated extent unit of width @count. Assign
+ * fake block numbers to jnodes corresponding to the inserted extent.
+ */
+static int append_last_extent(uf_coord_t *uf_coord, const reiser4_key *key,
+                             jnode **jnodes, int count)
+{
+       int result;
+       reiser4_extent new_ext;
+       reiser4_item_data idata;
+       coord_t *coord;
+       extent_coord_extension_t *ext_coord;
+       reiser4_extent *ext;
+       reiser4_block_nr block;
+       jnode *node;
+       int i;
+
+       coord = &uf_coord->coord;
+       ext_coord = &uf_coord->extension.extent;
+       ext = ext_by_ext_coord(uf_coord);
+
+       /* check correctness of position in the item */
+       assert("vs-228", coord->unit_pos == coord_last_unit_pos(coord));
+       assert("vs-1311", coord->between == AFTER_UNIT);
+       assert("vs-1302", ext_coord->pos_in_unit == ext_coord->width - 1);
+
+       if (!can_append(key, coord)) {
+               /* hole extent has to be inserted */
+               result = append_hole(coord, uf_coord->lh, key);
+               uf_coord->valid = 0;
+               return result;
+       }
+
+       if (count == 0)
+               return 0;
+
+       assert("", get_key_offset(key) == (loff_t)index_jnode(jnodes[0]) * PAGE_CACHE_SIZE);
+
+       result = DQUOT_ALLOC_BLOCK_NODIRTY(mapping_jnode(jnodes[0])->host,
+                                          count);
+       BUG_ON(result != 0);
+
+       switch (state_of_extent(ext)) {
+       case UNALLOCATED_EXTENT:
+               /*
+                * last extent unit of the file is unallocated one. Increase
+                * its width by @count
+                */
+               reiser4_set_extent(ext, UNALLOCATED_EXTENT_START,
+                                  extent_get_width(ext) + count);
+               znode_make_dirty(coord->node);
+
+               /* update coord extension */
+               ext_coord->width += count;
+               ON_DEBUG(extent_set_width
+                        (&uf_coord->extension.extent.extent,
+                         ext_coord->width));
+               break;
+
+       case HOLE_EXTENT:
+       case ALLOCATED_EXTENT:
+               /*
+                * last extent unit of the file is either hole or allocated
+                * one. Append one unallocated extent of width @count
+                */
+               reiser4_set_extent(&new_ext, UNALLOCATED_EXTENT_START, count);
+               init_new_extent(&idata, &new_ext, 1);
+               result = insert_into_item(coord, uf_coord->lh, key, &idata, 0);
+               uf_coord->valid = 0;
+               if (result)
+                       return result;
+               break;
+
+       default:
+               return RETERR(-EIO);
+       }
+
+       /*
+        * make sure that we hold long term locked twig node containing all
+        * jnodes we are about to capture
+        */
+       check_jnodes(uf_coord->lh->node, key, count);
+
+       /*
+        * assign fake block numbers to all jnodes. FIXME: make sure whether
+        * twig node containing inserted extent item is locked
+        */
+       block = fake_blocknr_unformatted(count);
+       for (i = 0; i < count; i ++, block ++) {
+               node = jnodes[i];
+               spin_lock_jnode(node);
+               JF_SET(node, JNODE_CREATED);
+               jnode_set_block(node, &block);
+               result = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+               BUG_ON(result != 0);
+               jnode_make_dirty_locked(node);
+               spin_unlock_jnode(node);
+       }
+       return count;
+}
+
+/**
+ * insert_first_hole - inser hole extent into tree
+ * @coord:
+ * @lh:
+ * @key:
+ *
+ *
+ */
+static int insert_first_hole(coord_t *coord, lock_handle *lh,
+                            const reiser4_key *key)
+{
+       reiser4_extent new_ext;
+       reiser4_item_data idata;
+       reiser4_key item_key;
+       reiser4_block_nr hole_width;
+
+       /* @coord must be set for inserting of new item */
+       assert("vs-711", coord_is_between_items(coord));
+
+       item_key = *key;
+       set_key_offset(&item_key, 0ull);
+
+       hole_width = ((get_key_offset(key) + current_blocksize - 1) >>
+                     current_blocksize_bits);
+       assert("vs-710", hole_width > 0);
+
+       /* compose body of hole extent and insert item into tree */
+       reiser4_set_extent(&new_ext, HOLE_EXTENT_START, hole_width);
+       init_new_extent(&idata, &new_ext, 1);
+       return insert_extent_by_coord(coord, &idata, &item_key, lh);
+}
+
+
+/**
+ * insert_first_extent - insert first file item
+ * @inode: inode of file
+ * @uf_coord: coord to start insertion from
+ * @jnodes: array of jnodes
+ * @count: number of jnodes in the array
+ * @inode:
+ *
+ * There are no items of file @inode in the tree yet. Insert unallocated extent
+ * of width @count into tree or hole extent if writing not to the
+ * beginning. Assign fake block numbers to jnodes corresponding to the inserted
+ * unallocated extent. Returns number of jnodes or error code.
+ */
+static int insert_first_extent(uf_coord_t *uf_coord, const reiser4_key *key,
+                              jnode **jnodes, int count,
+                              struct inode *inode)
+{
+       int result;
+       int i;
+       reiser4_extent new_ext;
+       reiser4_item_data idata;
+       reiser4_block_nr block;
+       unix_file_info_t *uf_info;
+       jnode *node;
+
+       /* first extent insertion starts at leaf level */
+       assert("vs-719", znode_get_level(uf_coord->coord.node) == LEAF_LEVEL);
+       assert("vs-711", coord_is_between_items(&uf_coord->coord));
+
+       if (get_key_offset(key) != 0) {
+               result = insert_first_hole(&uf_coord->coord, uf_coord->lh, key);
+               uf_coord->valid = 0;
+               uf_info = unix_file_inode_data(inode);
+
+               /*
+                * first item insertion is only possible when writing to empty
+                * file or performing tail conversion
+                */
+               assert("", (uf_info->container == UF_CONTAINER_EMPTY ||
+                           (reiser4_inode_get_flag(inode,
+                                                   REISER4_PART_MIXED) &&
+                            reiser4_inode_get_flag(inode,
+                                                   REISER4_PART_IN_CONV))));
+               /* if file was empty - update its state */
+               if (result == 0 && uf_info->container == UF_CONTAINER_EMPTY)
+                       uf_info->container = UF_CONTAINER_EXTENTS;
+               return result;
+       }
+
+       if (count == 0)
+               return 0;
+
+       result = DQUOT_ALLOC_BLOCK_NODIRTY(mapping_jnode(jnodes[0])->host, count);
+       BUG_ON(result != 0);
+
+       /*
+        * prepare for tree modification: compose body of item and item data
+        * structure needed for insertion
+        */
+       reiser4_set_extent(&new_ext, UNALLOCATED_EXTENT_START, count);
+       init_new_extent(&idata, &new_ext, 1);
+
+       /* insert extent item into the tree */
+       result = insert_extent_by_coord(&uf_coord->coord, &idata, key,
+                                       uf_coord->lh);
+       if (result)
+               return result;
+
+       /*
+        * make sure that we hold long term locked twig node containing all
+        * jnodes we are about to capture
+        */
+       check_jnodes(uf_coord->lh->node, key, count);
+       /*
+        * assign fake block numbers to all jnodes, capture and mark them dirty
+        */
+       block = fake_blocknr_unformatted(count);
+       for (i = 0; i < count; i ++, block ++) {
+               node = jnodes[i];
+               spin_lock_jnode(node);
+               JF_SET(node, JNODE_CREATED);
+               jnode_set_block(node, &block);
+               result = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+               BUG_ON(result != 0);
+               jnode_make_dirty_locked(node);
+               spin_unlock_jnode(node);
+       }
+
+       /*
+        * invalidate coordinate, research must be performed to continue
+        * because write will continue on twig level
+        */
+       uf_coord->valid = 0;
+       return count;
+}
+
+/**
+ * plug_hole - replace hole extent with unallocated and holes
+ * @uf_coord:
+ * @key:
+ * @node:
+ * @h: structure containing coordinate, lock handle, key, etc
+ *
+ * Creates an unallocated extent of width 1 within a hole. In worst case two
+ * additional extents can be created.
+ */
+static int plug_hole(uf_coord_t *uf_coord, const reiser4_key *key, int *how)
+{
+       struct replace_handle rh;
+       reiser4_extent *ext;
+       reiser4_block_nr width, pos_in_unit;
+       coord_t *coord;
+       extent_coord_extension_t *ext_coord;
+       int return_inserted_position;
+
+       check_uf_coord(uf_coord, key);
+
+       rh.coord = coord_by_uf_coord(uf_coord);
+       rh.lh = uf_coord->lh;
+       rh.flags = 0;
+
+       coord = coord_by_uf_coord(uf_coord);
+       ext_coord = ext_coord_by_uf_coord(uf_coord);
+       ext = ext_by_ext_coord(uf_coord);
+
+       width = ext_coord->width;
+       pos_in_unit = ext_coord->pos_in_unit;
+
+       *how = 0;
+       if (width == 1) {
+               reiser4_set_extent(ext, UNALLOCATED_EXTENT_START, 1);
+               znode_make_dirty(coord->node);
+               /* update uf_coord */
+               ON_DEBUG(ext_coord->extent = *ext);
+               *how = 1;
+               return 0;
+       } else if (pos_in_unit == 0) {
+               /* we deal with first element of extent */
+               if (coord->unit_pos) {
+                       /* there is an extent to the left */
+                       if (state_of_extent(ext - 1) == UNALLOCATED_EXTENT) {
+                               /*
+                                * left neighboring unit is an unallocated
+                                * extent. Increase its width and decrease
+                                * width of hole
+                                */
+                               extent_set_width(ext - 1,
+                                                extent_get_width(ext - 1) + 1);
+                               extent_set_width(ext, width - 1);
+                               znode_make_dirty(coord->node);
+
+                               /* update coord extension */
+                               coord->unit_pos--;
+                               ext_coord->width = extent_get_width(ext - 1);
+                               ext_coord->pos_in_unit = ext_coord->width - 1;
+                               ext_coord->ext_offset -= sizeof(reiser4_extent);
+                               ON_DEBUG(ext_coord->extent =
+                                        *extent_by_coord(coord));
+                               *how = 2;
+                               return 0;
+                       }
+               }
+               /* extent for replace */
+               reiser4_set_extent(&rh.overwrite, UNALLOCATED_EXTENT_START, 1);
+               /* extent to be inserted */
+               reiser4_set_extent(&rh.new_extents[0], HOLE_EXTENT_START,
+                                  width - 1);
+               rh.nr_new_extents = 1;
+
+               /* have reiser4_replace_extent to return with @coord and
+                  @uf_coord->lh set to unit which was replaced */
+               return_inserted_position = 0;
+               *how = 3;
+       } else if (pos_in_unit == width - 1) {
+               /* we deal with last element of extent */
+               if (coord->unit_pos < nr_units_extent(coord) - 1) {
+                       /* there is an extent unit to the right */
+                       if (state_of_extent(ext + 1) == UNALLOCATED_EXTENT) {
+                               /*
+                                * right neighboring unit is an unallocated
+                                * extent. Increase its width and decrease
+                                * width of hole
+                                */
+                               extent_set_width(ext + 1,
+                                                extent_get_width(ext + 1) + 1);
+                               extent_set_width(ext, width - 1);
+                               znode_make_dirty(coord->node);
+
+                               /* update coord extension */
+                               coord->unit_pos++;
+                               ext_coord->width = extent_get_width(ext + 1);
+                               ext_coord->pos_in_unit = 0;
+                               ext_coord->ext_offset += sizeof(reiser4_extent);
+                               ON_DEBUG(ext_coord->extent =
+                                        *extent_by_coord(coord));
+                               *how = 4;
+                               return 0;
+                       }
+               }
+               /* extent for replace */
+               reiser4_set_extent(&rh.overwrite, HOLE_EXTENT_START, width - 1);
+               /* extent to be inserted */
+               reiser4_set_extent(&rh.new_extents[0], UNALLOCATED_EXTENT_START,
+                                  1);
+               rh.nr_new_extents = 1;
+
+               /* have reiser4_replace_extent to return with @coord and
+                  @uf_coord->lh set to unit which was inserted */
+               return_inserted_position = 1;
+               *how = 5;
+       } else {
+               /* extent for replace */
+               reiser4_set_extent(&rh.overwrite, HOLE_EXTENT_START,
+                                  pos_in_unit);
+               /* extents to be inserted */
+               reiser4_set_extent(&rh.new_extents[0], UNALLOCATED_EXTENT_START,
+                                  1);
+               reiser4_set_extent(&rh.new_extents[1], HOLE_EXTENT_START,
+                                  width - pos_in_unit - 1);
+               rh.nr_new_extents = 2;
+
+               /* have reiser4_replace_extent to return with @coord and
+                  @uf_coord->lh set to first of units which were inserted */
+               return_inserted_position = 1;
+               *how = 6;
+       }
+       unit_key_by_coord(coord, &rh.paste_key);
+       set_key_offset(&rh.paste_key, get_key_offset(&rh.paste_key) +
+                      extent_get_width(&rh.overwrite) * current_blocksize);
+
+       uf_coord->valid = 0;
+       return reiser4_replace_extent(&rh, return_inserted_position);
+}
+
+/**
+ * overwrite_one_block -
+ * @uf_coord:
+ * @key:
+ * @node:
+ *
+ * If @node corresponds to hole extent - create unallocated extent for it and
+ * assign fake block number. If @node corresponds to allocated extent - assign
+ * block number of jnode
+ */
+static int overwrite_one_block(uf_coord_t *uf_coord, const reiser4_key *key,
+                              jnode *node, int *hole_plugged)
+{
+       int result;
+       extent_coord_extension_t *ext_coord;
+       reiser4_extent *ext;
+       reiser4_block_nr block;
+       int how;
+
+       assert("vs-1312", uf_coord->coord.between == AT_UNIT);
+
+       result = 0;
+       ext_coord = ext_coord_by_uf_coord(uf_coord);
+       ext = ext_by_ext_coord(uf_coord);
+       assert("", state_of_extent(ext) != UNALLOCATED_EXTENT);
+
+       switch (state_of_extent(ext)) {
+       case ALLOCATED_EXTENT:
+               block = extent_get_start(ext) + ext_coord->pos_in_unit;
+               break;
+
+       case HOLE_EXTENT:
+               result = DQUOT_ALLOC_BLOCK_NODIRTY(mapping_jnode(node)->host, 1);
+               BUG_ON(result != 0);
+               result = plug_hole(uf_coord, key, &how);
+               if (result)
+                       return result;
+               block = fake_blocknr_unformatted(1);
+               if (hole_plugged)
+                       *hole_plugged = 1;
+               JF_SET(node, JNODE_CREATED);
+               break;
+
+       default:
+               return RETERR(-EIO);
+       }
+
+       jnode_set_block(node, &block);
+       return 0;
+}
+
+/**
+ * move_coord - move coordinate forward
+ * @uf_coord:
+ *
+ * Move coordinate one data block pointer forward. Return 1 if coord is set to
+ * the last one already or is invalid.
+ */
+static int move_coord(uf_coord_t *uf_coord)
+{
+       extent_coord_extension_t *ext_coord;
+
+       if (uf_coord->valid == 0)
+               return 1;
+       ext_coord = &uf_coord->extension.extent;
+       ext_coord->pos_in_unit ++;
+       if (ext_coord->pos_in_unit < ext_coord->width)
+               /* coordinate moved within the unit */
+               return 0;
+
+       /* end of unit is reached. Try to move to next unit */
+       ext_coord->pos_in_unit = 0;
+       uf_coord->coord.unit_pos ++;
+       if (uf_coord->coord.unit_pos < ext_coord->nr_units) {
+               /* coordinate moved to next unit */
+               ext_coord->ext_offset += sizeof(reiser4_extent);
+               ext_coord->width =
+                       extent_get_width(ext_by_offset
+                                        (uf_coord->coord.node,
+                                         ext_coord->ext_offset));
+               ON_DEBUG(ext_coord->extent =
+                        *ext_by_offset(uf_coord->coord.node,
+                                       ext_coord->ext_offset));
+               return 0;
+       }
+       /* end of item is reached */
+       uf_coord->valid = 0;
+       return 1;
+}
+
+/**
+ * overwrite_extent -
+ * @inode:
+ *
+ * Returns number of handled jnodes.
+ */
+static int overwrite_extent(uf_coord_t *uf_coord, const reiser4_key *key,
+                           jnode **jnodes, int count, int *plugged_hole)
+{
+       int result;
+       reiser4_key k;
+       int i;
+       jnode *node;
+
+       k = *key;
+       for (i = 0; i < count; i ++) {
+               node = jnodes[i];
+               if (*jnode_get_block(node) == 0) {
+                       result = overwrite_one_block(uf_coord, &k, node, plugged_hole);
+                       if (result)
+                               return result;
+               }
+               /*
+                * make sure that we hold long term locked twig node containing
+                * all jnodes we are about to capture
+                */
+               check_jnodes(uf_coord->lh->node, &k, 1);
+               /*
+                * assign fake block numbers to all jnodes, capture and mark
+                * them dirty
+                */
+               spin_lock_jnode(node);
+               result = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+               BUG_ON(result != 0);
+               jnode_make_dirty_locked(node);
+               spin_unlock_jnode(node);
+
+               if (uf_coord->valid == 0)
+                       return i + 1;
+
+               check_uf_coord(uf_coord, &k);
+
+               if (move_coord(uf_coord)) {
+                       /*
+                        * failed to move to the next node pointer. Either end
+                        * of file or end of twig node is reached. In the later
+                        * case we might go to the right neighbor.
+                        */
+                       uf_coord->valid = 0;
+                       return i + 1;
+               }
+               set_key_offset(&k, get_key_offset(&k) + PAGE_CACHE_SIZE);
+       }
+
+       return count;
+}
+
+/**
+ * reiser4_update_extent
+ * @file:
+ * @jnodes:
+ * @count:
+ * @off:
+ *
+ */
+int reiser4_update_extent(struct inode *inode, jnode *node, loff_t pos,
+                 int *plugged_hole)
+{
+       int result;
+       znode *loaded;
+       uf_coord_t uf_coord;
+       coord_t *coord;
+       lock_handle lh;
+       reiser4_key key;
+
+       assert("", reiser4_lock_counters()->d_refs == 0);
+
+       key_by_inode_and_offset_common(inode, pos, &key);
+
+       init_uf_coord(&uf_coord, &lh);
+       coord = &uf_coord.coord;
+       result = find_file_item_nohint(coord, &lh, &key,
+                                      ZNODE_WRITE_LOCK, inode);
+       if (IS_CBKERR(result)) {
+               assert("", reiser4_lock_counters()->d_refs == 0);
+               return result;
+       }
+
+       result = zload(coord->node);
+       BUG_ON(result != 0);
+       loaded = coord->node;
+
+       if (coord->between == AFTER_UNIT) {
+               /*
+                * append existing extent item with unallocated extent of width
+                * nr_jnodes
+                */
+               init_coord_extension_extent(&uf_coord,
+                                           get_key_offset(&key));
+               result = append_last_extent(&uf_coord, &key,
+                                           &node, 1);
+       } else if (coord->between == AT_UNIT) {
+               /*
+                * overwrite
+                * not optimal yet. Will be optimized if new write will show
+                * performance win.
+                */
+               init_coord_extension_extent(&uf_coord,
+                                           get_key_offset(&key));
+               result = overwrite_extent(&uf_coord, &key,
+                                         &node, 1, plugged_hole);
+       } else {
+               /*
+                * there are no items of this file in the tree yet. Create
+                * first item of the file inserting one unallocated extent of
+                * width nr_jnodes
+                */
+               result = insert_first_extent(&uf_coord, &key, &node, 1, inode);
+       }
+       assert("", result == 1 || result < 0);
+       zrelse(loaded);
+       done_lh(&lh);
+       assert("", reiser4_lock_counters()->d_refs == 0);
+       return (result == 1) ? 0 : result;
+}
+
+/**
+ * update_extents
+ * @file:
+ * @jnodes:
+ * @count:
+ * @off:
+ *
+ */
+static int update_extents(struct file *file, jnode **jnodes, int count, loff_t pos)
+{
+       struct inode *inode;
+       struct hint hint;
+       reiser4_key key;
+       int result;
+       znode *loaded;
+
+       result = load_file_hint(file, &hint);
+       BUG_ON(result != 0);
+
+       inode = file->f_dentry->d_inode;
+       if (count != 0)
+               /*
+                * count == 0 is special case: expanding truncate
+                */
+               pos = (loff_t)index_jnode(jnodes[0]) << PAGE_CACHE_SHIFT;
+       key_by_inode_and_offset_common(inode, pos, &key);
+
+       assert("", reiser4_lock_counters()->d_refs == 0);
+
+       do {
+               result = find_file_item(&hint, &key, ZNODE_WRITE_LOCK, inode);
+               if (IS_CBKERR(result)) {
+                       assert("", reiser4_lock_counters()->d_refs == 0);
+                       return result;
+               }
+
+               result = zload(hint.ext_coord.coord.node);
+               BUG_ON(result != 0);
+               loaded = hint.ext_coord.coord.node;
+
+               if (hint.ext_coord.coord.between == AFTER_UNIT) {
+                       /*
+                        * append existing extent item with unallocated extent
+                        * of width nr_jnodes
+                        */
+                       if (hint.ext_coord.valid == 0)
+                               /* NOTE: get statistics on this */
+                               init_coord_extension_extent(&hint.ext_coord,
+                                                           get_key_offset(&key));
+                       result = append_last_extent(&hint.ext_coord, &key,
+                                                   jnodes, count);
+               } else if (hint.ext_coord.coord.between == AT_UNIT) {
+                       /*
+                        * overwrite
+                        * not optimal yet. Will be optimized if new write will
+                        * show performance win.
+                        */
+                       if (hint.ext_coord.valid == 0)
+                               /* NOTE: get statistics on this */
+                               init_coord_extension_extent(&hint.ext_coord,
+                                                           get_key_offset(&key));
+                       result = overwrite_extent(&hint.ext_coord, &key,
+                                                 jnodes, count, NULL);
+               } else {
+                       /*
+                        * there are no items of this file in the tree
+                        * yet. Create first item of the file inserting one
+                        * unallocated extent of * width nr_jnodes
+                        */
+                       result = insert_first_extent(&hint.ext_coord, &key,
+                                                    jnodes, count, inode);
+               }
+               zrelse(loaded);
+               if (result < 0) {
+                       done_lh(hint.ext_coord.lh);
+                       break;
+               }
+
+               jnodes += result;
+               count -= result;
+               set_key_offset(&key, get_key_offset(&key) + result * PAGE_CACHE_SIZE);
+
+               /* seal and unlock znode */
+               if (hint.ext_coord.valid)
+                       reiser4_set_hint(&hint, &key, ZNODE_WRITE_LOCK);
+               else
+                       reiser4_unset_hint(&hint);
+
+       } while (count > 0);
+
+       save_file_hint(file, &hint);
+       assert("", reiser4_lock_counters()->d_refs == 0);
+       return result;
+}
+
+/**
+ * write_extent_reserve_space - reserve space for extent write operation
+ * @inode:
+ *
+ * Estimates and reserves space which may be required for writing
+ * WRITE_GRANULARITY pages of file.
+ */
+static int write_extent_reserve_space(struct inode *inode)
+{
+       __u64 count;
+       reiser4_tree *tree;
+
+       /*
+        * to write WRITE_GRANULARITY pages to a file by extents we have to
+        * reserve disk space for:
+
+        * 1. find_file_item may have to insert empty node to the tree (empty
+        * leaf node between two extent items). This requires 1 block and
+        * number of blocks which are necessary to perform insertion of an
+        * internal item into twig level.
+
+        * 2. for each of written pages there might be needed 1 block and
+        * number of blocks which might be necessary to perform insertion of or
+        * paste to an extent item.
+
+        * 3. stat data update
+        */
+       tree = reiser4_tree_by_inode(inode);
+       count = estimate_one_insert_item(tree) +
+               WRITE_GRANULARITY * (1 + estimate_one_insert_into_item(tree)) +
+               estimate_one_insert_item(tree);
+       grab_space_enable();
+       return reiser4_grab_space(count, 0 /* flags */);
+}
+
+/**
+ * reiser4_write_extent - write method of extent item plugin
+ * @file: file to write to
+ * @buf: address of user-space buffer
+ * @count: number of bytes to write
+ * @pos: position in file to write to
+ *
+ */
+ssize_t reiser4_write_extent(struct file *file, const char __user *buf,
+                            size_t count, loff_t *pos)
+{
+       int have_to_update_extent;
+       int nr_pages, nr_dirty;
+       struct page *page;
+       jnode *jnodes[WRITE_GRANULARITY + 1];
+       struct inode *inode;
+       unsigned long index;
+       unsigned long end;
+       int i;
+       int to_page, page_off;
+       size_t left, written;
+       int result = 0;
+
+       inode = file->f_dentry->d_inode;
+       if (write_extent_reserve_space(inode))
+               return RETERR(-ENOSPC);
+
+       if (count == 0) {
+               /* truncate case */
+               update_extents(file, jnodes, 0, *pos);
+               return 0;
+       }
+
+       BUG_ON(get_current_context()->trans->atom != NULL);
+
+       left = count;
+       index = *pos >> PAGE_CACHE_SHIFT;
+       /* calculate number of pages which are to be written */
+       end = ((*pos + count - 1) >> PAGE_CACHE_SHIFT);
+       nr_pages = end - index + 1;
+       nr_dirty = 0;
+       assert("", nr_pages <= WRITE_GRANULARITY + 1);
+
+       /* get pages and jnodes */
+       for (i = 0; i < nr_pages; i ++) {
+               page = find_or_create_page(inode->i_mapping, index + i,
+                                          reiser4_ctx_gfp_mask_get());
+               if (page == NULL) {
+                       nr_pages = i;
+                       result = RETERR(-ENOMEM);
+                       goto out;
+               }
+
+               jnodes[i] = jnode_of_page(page);
+               if (IS_ERR(jnodes[i])) {
+                       unlock_page(page);
+                       page_cache_release(page);
+                       nr_pages = i;
+                       result = RETERR(-ENOMEM);
+                       goto out;
+               }
+               /* prevent jnode and page from disconnecting */
+               JF_SET(jnodes[i], JNODE_WRITE_PREPARED);
+               unlock_page(page);
+       }
+
+       BUG_ON(get_current_context()->trans->atom != NULL);
+
+       have_to_update_extent = 0;
+
+       page_off = (*pos & (PAGE_CACHE_SIZE - 1));
+       for (i = 0; i < nr_pages; i ++) {
+               to_page = PAGE_CACHE_SIZE - page_off;
+               if (to_page > left)
+                       to_page = left;
+               page = jnode_page(jnodes[i]);
+               if (page_offset(page) < inode->i_size &&
+                   !PageUptodate(page) && to_page != PAGE_CACHE_SIZE) {
+                       /*
+                        * the above is not optimal for partial write to last
+                        * page of file when file size is not at boundary of
+                        * page
+                        */
+                       lock_page(page);
+                       if (!PageUptodate(page)) {
+                               result = readpage_unix_file(NULL, page);
+                               BUG_ON(result != 0);
+                               /* wait for read completion */
+                               lock_page(page);
+                               BUG_ON(!PageUptodate(page));
+                       } else
+                               result = 0;
+                       unlock_page(page);
+               }
+
+               BUG_ON(get_current_context()->trans->atom != NULL);
+               fault_in_pages_readable(buf, to_page);
+               BUG_ON(get_current_context()->trans->atom != NULL);
+
+               lock_page(page);
+               if (!PageUptodate(page) && to_page != PAGE_CACHE_SIZE) {
+                       void *kaddr;
+
+                       kaddr = kmap_atomic(page, KM_USER0);
+                       memset(kaddr, 0, page_off);
+                       memset(kaddr + page_off + to_page, 0,
+                              PAGE_CACHE_SIZE - (page_off + to_page));
+                       flush_dcache_page(page);
+                       kunmap_atomic(kaddr, KM_USER0);
+               }
+
+               written = filemap_copy_from_user(page, page_off, buf, to_page);
+               if (unlikely(written != to_page)) {
+                       unlock_page(page);
+                       result = RETERR(-EFAULT);
+                       break;
+               }
+
+               flush_dcache_page(page);
+               reiser4_set_page_dirty_internal(page);
+               unlock_page(page);
+               nr_dirty++;
+
+               mark_page_accessed(page);
+               SetPageUptodate(page);
+
+               if (jnodes[i]->blocknr == 0)
+                       have_to_update_extent ++;
+
+               page_off = 0;
+               buf += to_page;
+               left -= to_page;
+               BUG_ON(get_current_context()->trans->atom != NULL);
+       }
+
+       if (have_to_update_extent) {
+               update_extents(file, jnodes, nr_dirty, *pos);
+       } else {
+               for (i = 0; i < nr_dirty; i ++) {
+                       int ret;
+                       spin_lock_jnode(jnodes[i]);
+                       ret = reiser4_try_capture(jnodes[i],
+                                                    ZNODE_WRITE_LOCK, 0);
+                       BUG_ON(ret != 0);
+                       jnode_make_dirty_locked(jnodes[i]);
+                       spin_unlock_jnode(jnodes[i]);
+               }
+       }
+out:
+       for (i = 0; i < nr_pages; i ++) {
+               page_cache_release(jnode_page(jnodes[i]));
+               JF_CLR(jnodes[i], JNODE_WRITE_PREPARED);
+               jput(jnodes[i]);
+       }
+
+       /* the only errors handled so far is ENOMEM and
+          EFAULT on copy_from_user  */
+
+       return (count - left) ? (count - left) : result;
+}
+
+static inline void zero_page(struct page *page)
+{
+       char *kaddr = kmap_atomic(page, KM_USER0);
+
+       memset(kaddr, 0, PAGE_CACHE_SIZE);
+       flush_dcache_page(page);
+       kunmap_atomic(kaddr, KM_USER0);
+       SetPageUptodate(page);
+       unlock_page(page);
+}
+
+int reiser4_do_readpage_extent(reiser4_extent * ext, reiser4_block_nr pos,
+                              struct page *page)
+{
+       jnode *j;
+       struct address_space *mapping;
+       unsigned long index;
+       oid_t oid;
+       reiser4_block_nr block;
+
+       mapping = page->mapping;
+       oid = get_inode_oid(mapping->host);
+       index = page->index;
+
+       switch (state_of_extent(ext)) {
+       case HOLE_EXTENT:
+               /*
+                * it is possible to have hole page with jnode, if page was
+                * eflushed previously.
+                */
+               j = jfind(mapping, index);
+               if (j == NULL) {
+                       zero_page(page);
+                       return 0;
+               }
+               spin_lock_jnode(j);
+               if (!jnode_page(j)) {
+                       jnode_attach_page(j, page);
+               } else {
+                       BUG_ON(jnode_page(j) != page);
+                       assert("vs-1504", jnode_page(j) == page);
+               }
+               block = *jnode_get_io_block(j);
+               spin_unlock_jnode(j);
+               if (block == 0) {
+                       zero_page(page);
+                       jput(j);
+                       return 0;
+               }
+               break;
+
+       case ALLOCATED_EXTENT:
+               j = jnode_of_page(page);
+               if (IS_ERR(j))
+                       return PTR_ERR(j);
+               if (*jnode_get_block(j) == 0) {
+                       reiser4_block_nr blocknr;
+
+                       blocknr = extent_get_start(ext) + pos;
+                       jnode_set_block(j, &blocknr);
+               } else
+                       assert("vs-1403",
+                              j->blocknr == extent_get_start(ext) + pos);
+               break;
+
+       case UNALLOCATED_EXTENT:
+               j = jfind(mapping, index);
+               assert("nikita-2688", j);
+               assert("vs-1426", jnode_page(j) == NULL);
+
+               spin_lock_jnode(j);
+               jnode_attach_page(j, page);
+               spin_unlock_jnode(j);
+               break;
+
+       default:
+               warning("vs-957", "wrong extent\n");
+               return RETERR(-EIO);
+       }
+
+       BUG_ON(j == 0);
+       reiser4_page_io(page, j, READ, reiser4_ctx_gfp_mask_get());
+       jput(j);
+       return 0;
+}
+
+/* Implements plugin->u.item.s.file.read operation for extent items. */
+int reiser4_read_extent(struct file *file, flow_t *flow, hint_t *hint)
+{
+       int result;
+       struct page *page;
+       unsigned long cur_page, next_page;
+       unsigned long page_off, count;
+       struct address_space *mapping;
+       loff_t file_off;
+       uf_coord_t *uf_coord;
+       coord_t *coord;
+       extent_coord_extension_t *ext_coord;
+       unsigned long nr_pages;
+       char *kaddr;
+
+       assert("vs-1353", current_blocksize == PAGE_CACHE_SIZE);
+       assert("vs-572", flow->user == 1);
+       assert("vs-1351", flow->length > 0);
+
+       uf_coord = &hint->ext_coord;
+
+       check_uf_coord(uf_coord, NULL);
+       assert("vs-33", uf_coord->lh == &hint->lh);
+
+       coord = &uf_coord->coord;
+       assert("vs-1119", znode_is_rlocked(coord->node));
+       assert("vs-1120", znode_is_loaded(coord->node));
+       assert("vs-1256", coord_matches_key_extent(coord, &flow->key));
+
+       mapping = file->f_dentry->d_inode->i_mapping;
+       ext_coord = &uf_coord->extension.extent;
+
+       /* offset in a file to start read from */
+       file_off = get_key_offset(&flow->key);
+       /* offset within the page to start read from */
+       page_off = (unsigned long)(file_off & (PAGE_CACHE_SIZE - 1));
+       /* bytes which can be read from the page which contains file_off */
+       count = PAGE_CACHE_SIZE - page_off;
+
+       /* index of page containing offset read is to start from */
+       cur_page = (unsigned long)(file_off >> PAGE_CACHE_SHIFT);
+       next_page = cur_page;
+       /* number of pages flow spans over */
+       nr_pages =
+           ((file_off + flow->length + PAGE_CACHE_SIZE -
+             1) >> PAGE_CACHE_SHIFT) - cur_page;
+
+       /* we start having twig node read locked. However, we do not want to
+          keep that lock all the time readahead works. So, set a sel and
+          release twig node. */
+       reiser4_set_hint(hint, &flow->key, ZNODE_READ_LOCK);
+       /* &hint->lh is done-ed */
+
+       do {
+               reiser4_txn_restart_current();
+               page = read_mapping_page(mapping, cur_page, file);
+               if (IS_ERR(page))
+                       return PTR_ERR(page);
+               lock_page(page);
+               if (!PageUptodate(page)) {
+                       unlock_page(page);
+                       page_cache_release(page);
+                       warning("jmacd-97178", "extent_read: page is not up to date");
+                       return RETERR(-EIO);
+               }
+               mark_page_accessed(page);
+               unlock_page(page);
+
+               /* If users can be writing to this page using arbitrary virtual
+                  addresses, take care about potential aliasing before reading
+                  the page on the kernel side.
+                */
+               if (mapping_writably_mapped(mapping))
+                       flush_dcache_page(page);
+
+               assert("nikita-3034", reiser4_schedulable());
+
+               /* number of bytes which are to be read from the page */
+               if (count > flow->length)
+                       count = flow->length;
+
+               result = fault_in_pages_writeable(flow->data, count);
+               if (result) {
+                       page_cache_release(page);
+                       return RETERR(-EFAULT);
+               }
+
+               kaddr = kmap_atomic(page, KM_USER0);
+               result = __copy_to_user_inatomic(flow->data,
+                                              kaddr + page_off, count);
+               kunmap_atomic(kaddr, KM_USER0);
+               if (result != 0) {
+                       kaddr = kmap(page);
+                       result = __copy_to_user(flow->data, kaddr + page_off, count);
+                       kunmap(page);
+                       if (unlikely(result))
+                               return RETERR(-EFAULT);
+               }
+
+               page_cache_release(page);
+
+               /* increase key (flow->key), update user area pointer (flow->data) */
+               move_flow_forward(flow, count);
+
+               page_off = 0;
+               cur_page ++;
+               count = PAGE_CACHE_SIZE;
+               nr_pages--;
+       } while (flow->length);
+
+       return 0;
+}
+
+/*
+   plugin->s.file.readpage
+   reiser4_read->unix_file_read->page_cache_readahead->reiser4_readpage->unix_file_readpage->extent_readpage
+   or
+   filemap_nopage->reiser4_readpage->readpage_unix_file->->readpage_extent
+
+   At the beginning: coord->node is read locked, zloaded, page is
+   locked, coord is set to existing unit inside of extent item (it is not necessary that coord matches to page->index)
+*/
+int reiser4_readpage_extent(void *vp, struct page *page)
+{
+       uf_coord_t *uf_coord = vp;
+       ON_DEBUG(coord_t * coord = &uf_coord->coord);
+       ON_DEBUG(reiser4_key key);
+
+       assert("vs-1040", PageLocked(page));
+       assert("vs-1050", !PageUptodate(page));
+       assert("vs-1039", page->mapping && page->mapping->host);
+
+       assert("vs-1044", znode_is_loaded(coord->node));
+       assert("vs-758", item_is_extent(coord));
+       assert("vs-1046", coord_is_existing_unit(coord));
+       assert("vs-1045", znode_is_rlocked(coord->node));
+       assert("vs-1047",
+              page->mapping->host->i_ino ==
+              get_key_objectid(item_key_by_coord(coord, &key)));
+       check_uf_coord(uf_coord, NULL);
+
+       return reiser4_do_readpage_extent(
+               ext_by_ext_coord(uf_coord),
+               uf_coord->extension.extent.pos_in_unit, page);
+}
+
+/**
+ * get_block_address_extent
+ * @coord:
+ * @block:
+ * @result:
+ *
+ *
+ */
+int get_block_address_extent(const coord_t *coord, sector_t block,
+                            sector_t *result)
+{
+       reiser4_extent *ext;
+
+       if (!coord_is_existing_unit(coord))
+               return RETERR(-EINVAL);
+
+       ext = extent_by_coord(coord);
+
+       if (state_of_extent(ext) != ALLOCATED_EXTENT)
+               /* FIXME: bad things may happen if it is unallocated extent */
+               *result = 0;
+       else {
+               reiser4_key key;
+
+               unit_key_by_coord(coord, &key);
+               assert("vs-1645",
+                      block >= get_key_offset(&key) >> current_blocksize_bits);
+               assert("vs-1646",
+                      block <
+                      (get_key_offset(&key) >> current_blocksize_bits) +
+                      extent_get_width(ext));
+               *result =
+                   extent_get_start(ext) + (block -
+                                            (get_key_offset(&key) >>
+                                             current_blocksize_bits));
+       }
+       return 0;
+}
+
+/*
+  plugin->u.item.s.file.append_key
+  key of first byte which is the next to last byte by addressed by this extent
+*/
+reiser4_key *append_key_extent(const coord_t * coord, reiser4_key * key)
+{
+       item_key_by_coord(coord, key);
+       set_key_offset(key,
+                      get_key_offset(key) + reiser4_extent_size(coord,
+                                                                nr_units_extent
+                                                                (coord)));
+
+       assert("vs-610", get_key_offset(key)
+              && (get_key_offset(key) & (current_blocksize - 1)) == 0);
+       return key;
+}
+
+/* plugin->u.item.s.file.init_coord_extension */
+void init_coord_extension_extent(uf_coord_t * uf_coord, loff_t lookuped)
+{
+       coord_t *coord;
+       extent_coord_extension_t *ext_coord;
+       reiser4_key key;
+       loff_t offset;
+
+       assert("vs-1295", uf_coord->valid == 0);
+
+       coord = &uf_coord->coord;
+       assert("vs-1288", coord_is_iplug_set(coord));
+       assert("vs-1327", znode_is_loaded(coord->node));
+
+       if (coord->between != AFTER_UNIT && coord->between != AT_UNIT)
+               return;
+
+       ext_coord = &uf_coord->extension.extent;
+       ext_coord->nr_units = nr_units_extent(coord);
+       ext_coord->ext_offset =
+           (char *)extent_by_coord(coord) - zdata(coord->node);
+       ext_coord->width = extent_get_width(extent_by_coord(coord));
+       ON_DEBUG(ext_coord->extent = *extent_by_coord(coord));
+       uf_coord->valid = 1;
+
+       /* pos_in_unit is the only uninitialized field in extended coord */
+       if (coord->between == AFTER_UNIT) {
+               assert("vs-1330",
+                      coord->unit_pos == nr_units_extent(coord) - 1);
+
+               ext_coord->pos_in_unit = ext_coord->width - 1;
+       } else {
+               /* AT_UNIT */
+               unit_key_by_coord(coord, &key);
+               offset = get_key_offset(&key);
+
+               assert("vs-1328", offset <= lookuped);
+               assert("vs-1329",
+                      lookuped <
+                      offset + ext_coord->width * current_blocksize);
+               ext_coord->pos_in_unit =
+                   ((lookuped - offset) >> current_blocksize_bits);
+       }
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/extent_flush_ops.c linux-2.6.20/fs/reiser4/plugin/item/extent_flush_ops.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/extent_flush_ops.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/extent_flush_ops.c      2007-05-06 14:50:43.811010720 +0400
@@ -0,0 +1,1028 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "item.h"
+#include "../../tree.h"
+#include "../../jnode.h"
+#include "../../super.h"
+#include "../../flush.h"
+#include "../../carry.h"
+#include "../object.h"
+
+#include <linux/pagemap.h>
+
+static reiser4_block_nr extent_unit_start(const coord_t * item);
+
+/* Return either first or last extent (depending on @side) of the item
+   @coord is set to. Set @pos_in_unit either to first or to last block
+   of extent. */
+static reiser4_extent *extent_utmost_ext(const coord_t * coord, sideof side,
+                                        reiser4_block_nr * pos_in_unit)
+{
+       reiser4_extent *ext;
+
+       if (side == LEFT_SIDE) {
+               /* get first extent of item */
+               ext = extent_item(coord);
+               *pos_in_unit = 0;
+       } else {
+               /* get last extent of item and last position within it */
+               assert("vs-363", side == RIGHT_SIDE);
+               ext = extent_item(coord) + coord_last_unit_pos(coord);
+               *pos_in_unit = extent_get_width(ext) - 1;
+       }
+
+       return ext;
+}
+
+/* item_plugin->f.utmost_child */
+/* Return the child. Coord is set to extent item. Find jnode corresponding
+   either to first or to last unformatted node pointed by the item */
+int utmost_child_extent(const coord_t * coord, sideof side, jnode ** childp)
+{
+       reiser4_extent *ext;
+       reiser4_block_nr pos_in_unit;
+
+       ext = extent_utmost_ext(coord, side, &pos_in_unit);
+
+       switch (state_of_extent(ext)) {
+       case HOLE_EXTENT:
+               *childp = NULL;
+               return 0;
+       case ALLOCATED_EXTENT:
+       case UNALLOCATED_EXTENT:
+               break;
+       default:
+               /* this should never happen */
+               assert("vs-1417", 0);
+       }
+
+       {
+               reiser4_key key;
+               reiser4_tree *tree;
+               unsigned long index;
+
+               if (side == LEFT_SIDE) {
+                       /* get key of first byte addressed by the extent */
+                       item_key_by_coord(coord, &key);
+               } else {
+                       /* get key of byte which next after last byte addressed by the extent */
+                       append_key_extent(coord, &key);
+               }
+
+               assert("vs-544",
+                      (get_key_offset(&key) >> PAGE_CACHE_SHIFT) < ~0ul);
+               /* index of first or last (depending on @side) page addressed
+                  by the extent */
+               index =
+                   (unsigned long)(get_key_offset(&key) >> PAGE_CACHE_SHIFT);
+               if (side == RIGHT_SIDE)
+                       index--;
+
+               tree = coord->node->zjnode.tree;
+               *childp = jlookup(tree, get_key_objectid(&key), index);
+       }
+
+       return 0;
+}
+
+/* item_plugin->f.utmost_child_real_block */
+/* Return the child's block, if allocated. */
+int
+utmost_child_real_block_extent(const coord_t * coord, sideof side,
+                              reiser4_block_nr * block)
+{
+       reiser4_extent *ext;
+
+       ext = extent_by_coord(coord);
+
+       switch (state_of_extent(ext)) {
+       case ALLOCATED_EXTENT:
+               *block = extent_get_start(ext);
+               if (side == RIGHT_SIDE)
+                       *block += extent_get_width(ext) - 1;
+               break;
+       case HOLE_EXTENT:
+       case UNALLOCATED_EXTENT:
+               *block = 0;
+               break;
+       default:
+               /* this should never happen */
+               assert("vs-1418", 0);
+       }
+
+       return 0;
+}
+
+/* item_plugin->f.scan */
+/* Performs leftward scanning starting from an unformatted node and its parent coordinate.
+   This scan continues, advancing the parent coordinate, until either it encounters a
+   formatted child or it finishes scanning this node.
+
+   If unallocated, the entire extent must be dirty and in the same atom.  (Actually, I'm
+   not sure this is last property (same atom) is enforced, but it should be the case since
+   one atom must write the parent and the others must read the parent, thus fusing?).  In
+   any case, the code below asserts this case for unallocated extents.  Unallocated
+   extents are thus optimized because we can skip to the endpoint when scanning.
+
+   It returns control to reiser4_scan_extent, handles these terminating conditions,
+   e.g., by loading the next twig.
+*/
+int reiser4_scan_extent(flush_scan * scan)
+{
+       coord_t coord;
+       jnode *neighbor;
+       unsigned long scan_index, unit_index, unit_width, scan_max, scan_dist;
+       reiser4_block_nr unit_start;
+       __u64 oid;
+       reiser4_key key;
+       int ret = 0, allocated, incr;
+       reiser4_tree *tree;
+
+       if (!JF_ISSET(scan->node, JNODE_DIRTY)) {
+               scan->stop = 1;
+               return 0;       /* Race with truncate, this node is already
+                                * truncated. */
+       }
+
+       coord_dup(&coord, &scan->parent_coord);
+
+       assert("jmacd-1404", !reiser4_scan_finished(scan));
+       assert("jmacd-1405", jnode_get_level(scan->node) == LEAF_LEVEL);
+       assert("jmacd-1406", jnode_is_unformatted(scan->node));
+
+       /* The scan_index variable corresponds to the current page index of the
+          unformatted block scan position. */
+       scan_index = index_jnode(scan->node);
+
+       assert("jmacd-7889", item_is_extent(&coord));
+
+      repeat:
+       /* objectid of file */
+       oid = get_key_objectid(item_key_by_coord(&coord, &key));
+
+       allocated = !extent_is_unallocated(&coord);
+       /* Get the values of this extent unit: */
+       unit_index = extent_unit_index(&coord);
+       unit_width = extent_unit_width(&coord);
+       unit_start = extent_unit_start(&coord);
+
+       assert("jmacd-7187", unit_width > 0);
+       assert("jmacd-7188", scan_index >= unit_index);
+       assert("jmacd-7189", scan_index <= unit_index + unit_width - 1);
+
+       /* Depending on the scan direction, we set different maximum values for scan_index
+          (scan_max) and the number of nodes that would be passed if the scan goes the
+          entire way (scan_dist).  Incr is an integer reflecting the incremental
+          direction of scan_index. */
+       if (reiser4_scanning_left(scan)) {
+               scan_max = unit_index;
+               scan_dist = scan_index - unit_index;
+               incr = -1;
+       } else {
+               scan_max = unit_index + unit_width - 1;
+               scan_dist = scan_max - unit_index;
+               incr = +1;
+       }
+
+       tree = coord.node->zjnode.tree;
+
+       /* If the extent is allocated we have to check each of its blocks.  If the extent
+          is unallocated we can skip to the scan_max. */
+       if (allocated) {
+               do {
+                       neighbor = jlookup(tree, oid, scan_index);
+                       if (neighbor == NULL)
+                               goto stop_same_parent;
+
+                       if (scan->node != neighbor
+                           && !reiser4_scan_goto(scan, neighbor)) {
+                               /* @neighbor was jput() by reiser4_scan_goto */
+                               goto stop_same_parent;
+                       }
+
+                       ret = scan_set_current(scan, neighbor, 1, &coord);
+                       if (ret != 0) {
+                               goto exit;
+                       }
+
+                       /* reference to @neighbor is stored in @scan, no need
+                          to jput(). */
+                       scan_index += incr;
+
+               } while (incr + scan_max != scan_index);
+
+       } else {
+               /* Optimized case for unallocated extents, skip to the end. */
+               neighbor = jlookup(tree, oid, scan_max /*index */ );
+               if (neighbor == NULL) {
+                       /* Race with truncate */
+                       scan->stop = 1;
+                       ret = 0;
+                       goto exit;
+               }
+
+               assert("zam-1043",
+                      reiser4_blocknr_is_fake(jnode_get_block(neighbor)));
+
+               ret = scan_set_current(scan, neighbor, scan_dist, &coord);
+               if (ret != 0) {
+                       goto exit;
+               }
+       }
+
+       if (coord_sideof_unit(&coord, scan->direction) == 0
+           && item_is_extent(&coord)) {
+               /* Continue as long as there are more extent units. */
+
+               scan_index =
+                   extent_unit_index(&coord) +
+                   (reiser4_scanning_left(scan) ?
+                    extent_unit_width(&coord) - 1 : 0);
+               goto repeat;
+       }
+
+       if (0) {
+             stop_same_parent:
+
+               /* If we are scanning left and we stop in the middle of an allocated
+                  extent, we know the preceder immediately.. */
+               /* middle of extent is (scan_index - unit_index) != 0. */
+               if (reiser4_scanning_left(scan) &&
+                   (scan_index - unit_index) != 0) {
+                       /* FIXME(B): Someone should step-through and verify that this preceder
+                          calculation is indeed correct. */
+                       /* @unit_start is starting block (number) of extent
+                          unit. Flush stopped at the @scan_index block from
+                          the beginning of the file, which is (scan_index -
+                          unit_index) block within extent.
+                        */
+                       if (unit_start) {
+                               /* skip preceder update when we are at hole */
+                               scan->preceder_blk =
+                                   unit_start + scan_index - unit_index;
+                               check_preceder(scan->preceder_blk);
+                       }
+               }
+
+               /* In this case, we leave coord set to the parent of scan->node. */
+               scan->stop = 1;
+
+       } else {
+               /* In this case, we are still scanning, coord is set to the next item which is
+                  either off-the-end of the node or not an extent. */
+               assert("jmacd-8912", scan->stop == 0);
+               assert("jmacd-7812",
+                      (coord_is_after_sideof_unit(&coord, scan->direction)
+                       || !item_is_extent(&coord)));
+       }
+
+       ret = 0;
+      exit:
+       return ret;
+}
+
+/* ask block allocator for some blocks */
+static void extent_allocate_blocks(reiser4_blocknr_hint *preceder,
+                                  reiser4_block_nr wanted_count,
+                                  reiser4_block_nr *first_allocated,
+                                  reiser4_block_nr *allocated,
+                                  block_stage_t block_stage)
+{
+       *allocated = wanted_count;
+       preceder->max_dist = 0; /* scan whole disk, if needed */
+
+       /* that number of blocks (wanted_count) is either in UNALLOCATED or in GRABBED */
+       preceder->block_stage = block_stage;
+
+       /* FIXME: we do not handle errors here now */
+       check_me("vs-420",
+                reiser4_alloc_blocks(preceder, first_allocated, allocated,
+                                     BA_PERMANENT) == 0);
+       /* update flush_pos's preceder to last allocated block number */
+       preceder->blk = *first_allocated + *allocated - 1;
+}
+
+/* when on flush time unallocated extent is to be replaced with allocated one it may happen that one unallocated extent
+   will have to be replaced with set of allocated extents. In this case insert_into_item will be called which may have
+   to add new nodes into tree. Space for that is taken from inviolable reserve (5%). */
+static reiser4_block_nr reserve_replace(void)
+{
+       reiser4_block_nr grabbed, needed;
+
+       grabbed = get_current_context()->grabbed_blocks;
+       needed = estimate_one_insert_into_item(current_tree);
+       check_me("vpf-340", !reiser4_grab_space_force(needed, BA_RESERVED));
+       return grabbed;
+}
+
+static void free_replace_reserved(reiser4_block_nr grabbed)
+{
+       reiser4_context *ctx;
+
+       ctx = get_current_context();
+       grabbed2free(ctx, get_super_private(ctx->super),
+                    ctx->grabbed_blocks - grabbed);
+}
+
+/* Block offset of first block addressed by unit */
+__u64 extent_unit_index(const coord_t * item)
+{
+       reiser4_key key;
+
+       assert("vs-648", coord_is_existing_unit(item));
+       unit_key_by_coord(item, &key);
+       return get_key_offset(&key) >> current_blocksize_bits;
+}
+
+/* AUDIT shouldn't return value be of reiser4_block_nr type?
+   Josh's answer: who knows?  Is a "number of blocks" the same type as "block offset"? */
+__u64 extent_unit_width(const coord_t * item)
+{
+       assert("vs-649", coord_is_existing_unit(item));
+       return width_by_coord(item);
+}
+
+/* Starting block location of this unit */
+static reiser4_block_nr extent_unit_start(const coord_t * item)
+{
+       return extent_get_start(extent_by_coord(item));
+}
+
+/**
+ * split_allocated_extent -
+ * @coord:
+ * @pos_in_unit:
+ *
+ * replace allocated extent with two allocated extents
+ */
+static int split_allocated_extent(coord_t *coord, reiser4_block_nr pos_in_unit)
+{
+       int result;
+       struct replace_handle *h;
+       reiser4_extent *ext;
+       reiser4_block_nr grabbed;
+
+       ext = extent_by_coord(coord);
+       assert("vs-1410", state_of_extent(ext) == ALLOCATED_EXTENT);
+       assert("vs-1411", extent_get_width(ext) > pos_in_unit);
+
+       h = kmalloc(sizeof(*h), reiser4_ctx_gfp_mask_get());
+       if (h == NULL)
+               return RETERR(-ENOMEM);
+       h->coord = coord;
+       h->lh = znode_lh(coord->node);
+       h->pkey = &h->key;
+       unit_key_by_coord(coord, h->pkey);
+       set_key_offset(h->pkey,
+                      (get_key_offset(h->pkey) +
+                       pos_in_unit * current_blocksize));
+       reiser4_set_extent(&h->overwrite, extent_get_start(ext),
+                          pos_in_unit);
+       reiser4_set_extent(&h->new_extents[0],
+                          extent_get_start(ext) + pos_in_unit,
+                          extent_get_width(ext) - pos_in_unit);
+       h->nr_new_extents = 1;
+       h->flags = COPI_DONT_SHIFT_LEFT;
+       h->paste_key = h->key;
+
+       /* reserve space for extent unit paste, @grabbed is reserved before */
+       grabbed = reserve_replace();
+       result = reiser4_replace_extent(h, 0 /* leave @coord set to overwritten
+                                               extent */);
+       /* restore reserved */
+       free_replace_reserved(grabbed);
+       kfree(h);
+       return result;
+}
+
+/* replace extent @ext by extent @replace. Try to merge @replace with previous extent of the item (if there is
+   one). Return 1 if it succeeded, 0 - otherwise */
+static int try_to_merge_with_left(coord_t *coord, reiser4_extent *ext,
+                      reiser4_extent *replace)
+{
+       assert("vs-1415", extent_by_coord(coord) == ext);
+
+       if (coord->unit_pos == 0
+           || state_of_extent(ext - 1) != ALLOCATED_EXTENT)
+               /* @ext either does not exist or is not allocated extent */
+               return 0;
+       if (extent_get_start(ext - 1) + extent_get_width(ext - 1) !=
+           extent_get_start(replace))
+               return 0;
+
+       /* we can glue, widen previous unit */
+       extent_set_width(ext - 1,
+                        extent_get_width(ext - 1) + extent_get_width(replace));
+
+       if (extent_get_width(ext) != extent_get_width(replace)) {
+               /* make current extent narrower */
+               if (state_of_extent(ext) == ALLOCATED_EXTENT)
+                       extent_set_start(ext,
+                                        extent_get_start(ext) +
+                                        extent_get_width(replace));
+               extent_set_width(ext,
+                                extent_get_width(ext) -
+                                extent_get_width(replace));
+       } else {
+               /* current extent completely glued with its left neighbor, remove it */
+               coord_t from, to;
+
+               coord_dup(&from, coord);
+               from.unit_pos = nr_units_extent(coord) - 1;
+               coord_dup(&to, &from);
+
+               /* currently cut from extent can cut either from the beginning or from the end. Move place which got
+                  freed after unit removal to end of item */
+               memmove(ext, ext + 1,
+                       (from.unit_pos -
+                        coord->unit_pos) * sizeof(reiser4_extent));
+               /* wipe part of item which is going to be cut, so that node_check will not be confused */
+               cut_node_content(&from, &to, NULL, NULL, NULL);
+       }
+       znode_make_dirty(coord->node);
+       /* move coord back */
+       coord->unit_pos--;
+       return 1;
+}
+
+/**
+ * conv_extent - replace extent with 2 ones
+ * @coord: coordinate of extent to be replaced
+ * @replace: extent to overwrite the one @coord is set to
+ *
+ * Overwrites extent @coord is set to and paste one extent unit after
+ * overwritten one if @replace is shorter than initial extent
+ */
+static int conv_extent(coord_t *coord, reiser4_extent *replace)
+{
+       int result;
+       struct replace_handle *h;
+       reiser4_extent *ext;
+       reiser4_block_nr start, width, new_width;
+       reiser4_block_nr grabbed;
+       extent_state state;
+
+       ext = extent_by_coord(coord);
+       state = state_of_extent(ext);
+       start = extent_get_start(ext);
+       width = extent_get_width(ext);
+       new_width = extent_get_width(replace);
+
+       assert("vs-1458", (state == UNALLOCATED_EXTENT ||
+                          state == ALLOCATED_EXTENT));
+       assert("vs-1459", width >= new_width);
+
+       if (try_to_merge_with_left(coord, ext, replace)) {
+               /* merged @replace with left neighbor. Current unit is either
+                  removed or narrowed */
+               return 0;
+       }
+
+       if (width == new_width) {
+               /* replace current extent with @replace */
+               *ext = *replace;
+               znode_make_dirty(coord->node);
+               return 0;
+       }
+
+       h = kmalloc(sizeof(*h), reiser4_ctx_gfp_mask_get());
+       if (h == NULL)
+               return RETERR(-ENOMEM);
+       h->coord = coord;
+       h->lh = znode_lh(coord->node);
+       h->pkey = &h->key;
+       unit_key_by_coord(coord, h->pkey);
+       set_key_offset(h->pkey,
+                      (get_key_offset(h->pkey) + new_width * current_blocksize));
+       h->overwrite = *replace;
+
+       /* replace @ext with @replace and padding extent */
+       reiser4_set_extent(&h->new_extents[0],
+                          (state == ALLOCATED_EXTENT) ?
+                          (start + new_width) :
+                          UNALLOCATED_EXTENT_START,
+                          width - new_width);
+       h->nr_new_extents = 1;
+       h->flags = COPI_DONT_SHIFT_LEFT;
+       h->paste_key = h->key;
+
+       /* reserve space for extent unit paste, @grabbed is reserved before */
+       grabbed = reserve_replace();
+       result = reiser4_replace_extent(h, 0 /* leave @coord set to overwritten
+                                               extent */);
+
+       /* restore reserved */
+       free_replace_reserved(grabbed);
+       kfree(h);
+       return result;
+}
+
+/**
+ * assign_real_blocknrs
+ * @flush_pos:
+ * @oid: objectid of file jnodes to assign block number to belongs to
+ * @index: first jnode on the range
+ * @count: number of jnodes to assign block numbers to
+ * @first: start of allocated block range
+ *
+ * Assigns block numbers to each of @count jnodes. Index of first jnode is
+ * @index. Jnodes get lookuped with jlookup.
+ */
+static void assign_real_blocknrs(flush_pos_t *flush_pos, oid_t oid,
+                                unsigned long index, reiser4_block_nr count,
+                                reiser4_block_nr first)
+{
+       unsigned long i;
+       reiser4_tree *tree;
+       txn_atom *atom;
+       int nr;
+
+       atom = atom_locked_by_fq(flush_pos->fq);
+       assert("vs-1468", atom);
+       BUG_ON(atom == NULL);
+
+       nr = 0;
+       tree = current_tree;
+       for (i = 0; i < count; ++i, ++index) {
+               jnode *node;
+
+               node = jlookup(tree, oid, index);
+               assert("", node != NULL);
+               BUG_ON(node == NULL);
+
+               spin_lock_jnode(node);
+               assert("", !jnode_is_flushprepped(node));
+               assert("vs-1475", node->atom == atom);
+               assert("vs-1476", atomic_read(&node->x_count) > 0);
+
+               JF_CLR(node, JNODE_FLUSH_RESERVED);
+               jnode_set_block(node, &first);
+               unformatted_make_reloc(node, flush_pos->fq);
+               ON_DEBUG(count_jnode(node->atom, node, NODE_LIST(node),
+                                    FQ_LIST, 0));
+               spin_unlock_jnode(node);
+               first++;
+
+               atomic_dec(&node->x_count);
+               nr ++;
+       }
+
+       spin_unlock_atom(atom);
+       return;
+}
+
+/**
+ * make_node_ovrwr - assign node to overwrite set
+ * @jnodes: overwrite set list head
+ * @node: jnode to belong to overwrite set
+ *
+ * Sets OVRWR jnode state bit and puts @node to the end of list head @jnodes
+ * which is an accumulator for nodes before they get to overwrite set list of
+ * atom.
+ */
+static void make_node_ovrwr(struct list_head *jnodes, jnode *node)
+{
+       spin_lock_jnode(node);
+
+       assert("zam-917", !JF_ISSET(node, JNODE_RELOC));
+       assert("zam-918", !JF_ISSET(node, JNODE_OVRWR));
+
+       JF_SET(node, JNODE_OVRWR);
+       list_move_tail(&node->capture_link, jnodes);
+       ON_DEBUG(count_jnode(node->atom, node, DIRTY_LIST, OVRWR_LIST, 0));
+
+       spin_unlock_jnode(node);
+}
+
+/**
+ * mark_jnodes_overwrite - put bunch of jnodes to overwrite set
+ * @flush_pos: flush position
+ * @oid: objectid of file jnodes belong to
+ * @index: starting index
+ * @width: extent width
+ *
+ * Puts nodes of one extent (file objectid @oid, extent width @width) to atom's
+ * overwrite set. Starting from the one with index @index. If end of slum is
+ * detected (node is not found or flushprepped) - stop iterating and set flush
+ * position's state to POS_INVALID.
+ */
+static void mark_jnodes_overwrite(flush_pos_t *flush_pos, oid_t oid,
+                                 unsigned long index, reiser4_block_nr width)
+{
+       unsigned long i;
+       reiser4_tree *tree;
+       jnode *node;
+       txn_atom *atom;
+       LIST_HEAD(jnodes);
+
+       tree = current_tree;
+
+       atom = atom_locked_by_fq(reiser4_pos_fq(flush_pos));
+       assert("vs-1478", atom);
+
+       for (i = flush_pos->pos_in_unit; i < width; i++, index++) {
+               node = jlookup(tree, oid, index);
+               if (!node) {
+                       flush_pos->state = POS_INVALID;
+                       break;
+               }
+               if (jnode_check_flushprepped(node)) {
+                       flush_pos->state = POS_INVALID;
+                       atomic_dec(&node->x_count);
+                       break;
+               }
+               if (node->atom != atom) {
+                       flush_pos->state = POS_INVALID;
+                       atomic_dec(&node->x_count);
+                       break;
+               }
+               make_node_ovrwr(&jnodes, node);
+               atomic_dec(&node->x_count);
+       }
+
+       list_splice_init(&jnodes, ATOM_OVRWR_LIST(atom)->prev);
+       spin_unlock_atom(atom);
+}
+
+/**
+ * allocated_extent_slum_size
+ * @flush_pos:
+ * @oid:
+ * @index:
+ * @count:
+ *
+ *
+ */
+static int allocated_extent_slum_size(flush_pos_t *flush_pos, oid_t oid,
+                                     unsigned long index, unsigned long count)
+{
+       unsigned long i;
+       reiser4_tree *tree;
+       txn_atom *atom;
+       int nr;
+
+       atom = atom_locked_by_fq(reiser4_pos_fq(flush_pos));
+       assert("vs-1468", atom);
+
+       nr = 0;
+       tree = current_tree;
+       for (i = 0; i < count; ++i, ++index) {
+               jnode *node;
+
+               node = jlookup(tree, oid, index);
+               if (!node)
+                       break;
+
+               if (jnode_check_flushprepped(node)) {
+                       atomic_dec(&node->x_count);
+                       break;
+               }
+
+               if (node->atom != atom) {
+                       /*
+                        * this is possible on overwrite: extent_write may
+                        * capture several unformatted nodes without capturing
+                        * any formatted nodes.
+                        */
+                       atomic_dec(&node->x_count);
+                       break;
+               }
+
+               assert("vs-1476", atomic_read(&node->x_count) > 1);
+               atomic_dec(&node->x_count);
+               nr ++;
+       }
+
+       spin_unlock_atom(atom);
+       return nr;
+}
+
+/**
+ * alloc_extent
+ * @flush_pos:
+ *
+ *
+ * this is called by handle_pos_on_twig to proceed extent unit flush_pos->coord
+ * is set to. It is to prepare for flushing sequence of not flushprepped nodes
+ * (slum). It supposes that slum starts at flush_pos->pos_in_unit position
+ * within the extent. Slum gets to relocate set if flush_pos->leaf_relocate is
+ * set to 1 and to overwrite set otherwise
+ */
+int reiser4_alloc_extent(flush_pos_t *flush_pos)
+{
+       coord_t *coord;
+       reiser4_extent *ext;
+       reiser4_extent replace_ext;
+       oid_t oid;
+       reiser4_block_nr protected;
+       reiser4_block_nr start;
+       __u64 index;
+       __u64 width;
+       extent_state state;
+       int result;
+       reiser4_block_nr first_allocated;
+       __u64 allocated;
+       reiser4_key key;
+       block_stage_t block_stage;
+
+       assert("vs-1468", flush_pos->state == POS_ON_EPOINT);
+       assert("vs-1469", coord_is_existing_unit(&flush_pos->coord)
+              && item_is_extent(&flush_pos->coord));
+
+       coord = &flush_pos->coord;
+
+       ext = extent_by_coord(coord);
+       state = state_of_extent(ext);
+       if (state == HOLE_EXTENT) {
+               flush_pos->state = POS_INVALID;
+               return 0;
+       }
+
+       item_key_by_coord(coord, &key);
+       oid = get_key_objectid(&key);
+       index = extent_unit_index(coord) + flush_pos->pos_in_unit;
+       start = extent_get_start(ext);
+       width = extent_get_width(ext);
+
+       assert("vs-1457", width > flush_pos->pos_in_unit);
+
+       if (flush_pos->leaf_relocate || state == UNALLOCATED_EXTENT) {
+               /* relocate */
+               if (flush_pos->pos_in_unit) {
+                       /* split extent unit into two */
+                       result =
+                           split_allocated_extent(coord,
+                                                  flush_pos->pos_in_unit);
+                       flush_pos->pos_in_unit = 0;
+                       return result;
+               }
+
+               /* limit number of nodes to allocate */
+               if (flush_pos->nr_to_write < width)
+                       width = flush_pos->nr_to_write;
+
+               if (state == ALLOCATED_EXTENT) {
+                       /*
+                        * all protected nodes are not flushprepped, therefore
+                        * they are counted as flush_reserved
+                        */
+                       block_stage = BLOCK_FLUSH_RESERVED;
+                       protected = allocated_extent_slum_size(flush_pos, oid,
+                                                              index, width);
+                       if (protected == 0) {
+                               flush_pos->state = POS_INVALID;
+                               flush_pos->pos_in_unit = 0;
+                               return 0;
+                       }
+               } else {
+                       block_stage = BLOCK_UNALLOCATED;
+                       protected = width;
+               }
+
+               /*
+                * look at previous unit if possible. If it is allocated, make
+                * preceder more precise
+                */
+               if (coord->unit_pos &&
+                   (state_of_extent(ext - 1) == ALLOCATED_EXTENT))
+                       reiser4_pos_hint(flush_pos)->blk =
+                               extent_get_start(ext - 1) +
+                               extent_get_width(ext - 1);
+
+               /* allocate new block numbers for protected nodes */
+               extent_allocate_blocks(reiser4_pos_hint(flush_pos),
+                                      protected,
+                                      &first_allocated, &allocated,
+                                      block_stage);
+
+               if (state == ALLOCATED_EXTENT)
+                       /*
+                        * on relocating - free nodes which are going to be
+                        * relocated
+                        */
+                       reiser4_dealloc_blocks(&start, &allocated,
+                                              BLOCK_ALLOCATED, BA_DEFER);
+
+               /* assign new block numbers to protected nodes */
+               assign_real_blocknrs(flush_pos, oid, index, allocated, first_allocated);
+
+               /* prepare extent which will replace current one */
+               reiser4_set_extent(&replace_ext, first_allocated, allocated);
+
+               /* adjust extent item */
+               result = conv_extent(coord, &replace_ext);
+               if (result != 0 && result != -ENOMEM) {
+                       warning("vs-1461",
+                               "Failed to allocate extent. Should not happen\n");
+                       return result;
+               }
+
+               /*
+                * break flush: we prepared for flushing as many blocks as we
+                * were asked for
+                */
+               if (flush_pos->nr_to_write == allocated)
+                       flush_pos->state = POS_INVALID;
+       } else {
+               /* overwrite */
+               mark_jnodes_overwrite(flush_pos, oid, index, width);
+       }
+       flush_pos->pos_in_unit = 0;
+       return 0;
+}
+
+/* if @key is glueable to the item @coord is set to */
+static int must_insert(const coord_t *coord, const reiser4_key *key)
+{
+       reiser4_key last;
+
+       if (item_id_by_coord(coord) == EXTENT_POINTER_ID
+           && keyeq(append_key_extent(coord, &last), key))
+               return 0;
+       return 1;
+}
+
+/* copy extent @copy to the end of @node. It may have to either insert new item after the last one, or append last item,
+   or modify last unit of last item to have greater width */
+static int put_unit_to_end(znode *node, const reiser4_key *key,
+                          reiser4_extent *copy_ext)
+{
+       int result;
+       coord_t coord;
+       cop_insert_flag flags;
+       reiser4_extent *last_ext;
+       reiser4_item_data data;
+
+       /* set coord after last unit in an item */
+       coord_init_last_unit(&coord, node);
+       coord.between = AFTER_UNIT;
+
+       flags =
+           COPI_DONT_SHIFT_LEFT | COPI_DONT_SHIFT_RIGHT | COPI_DONT_ALLOCATE;
+       if (must_insert(&coord, key)) {
+               result =
+                   insert_by_coord(&coord, init_new_extent(&data, copy_ext, 1),
+                                   key, NULL /*lh */ , flags);
+
+       } else {
+               /* try to glue with last unit */
+               last_ext = extent_by_coord(&coord);
+               if (state_of_extent(last_ext) &&
+                   extent_get_start(last_ext) + extent_get_width(last_ext) ==
+                   extent_get_start(copy_ext)) {
+                       /* widen last unit of node */
+                       extent_set_width(last_ext,
+                                        extent_get_width(last_ext) +
+                                        extent_get_width(copy_ext));
+                       znode_make_dirty(node);
+                       return 0;
+               }
+
+               /* FIXME: put an assertion here that we can not merge last unit in @node and new unit */
+               result =
+                   insert_into_item(&coord, NULL /*lh */ , key,
+                                    init_new_extent(&data, copy_ext, 1),
+                                    flags);
+       }
+
+       assert("vs-438", result == 0 || result == -E_NODE_FULL);
+       return result;
+}
+
+/* @coord is set to extent unit */
+squeeze_result squalloc_extent(znode *left, const coord_t *coord,
+                              flush_pos_t *flush_pos,
+                              reiser4_key *stop_key)
+{
+       reiser4_extent *ext;
+       __u64 index;
+       __u64 width;
+       reiser4_block_nr start;
+       extent_state state;
+       oid_t oid;
+       reiser4_block_nr first_allocated;
+       __u64 allocated;
+       __u64 protected;
+       reiser4_extent copy_extent;
+       reiser4_key key;
+       int result;
+       block_stage_t block_stage;
+
+       assert("vs-1457", flush_pos->pos_in_unit == 0);
+       assert("vs-1467", coord_is_leftmost_unit(coord));
+       assert("vs-1467", item_is_extent(coord));
+
+       ext = extent_by_coord(coord);
+       index = extent_unit_index(coord);
+       start = extent_get_start(ext);
+       width = extent_get_width(ext);
+       state = state_of_extent(ext);
+       unit_key_by_coord(coord, &key);
+       oid = get_key_objectid(&key);
+
+       if ((flush_pos->leaf_relocate && state == ALLOCATED_EXTENT) ||
+           (state == UNALLOCATED_EXTENT)) {
+               /* relocate */
+               if (state == ALLOCATED_EXTENT) {
+                       /* all protected nodes are not flushprepped, therefore
+                        * they are counted as flush_reserved */
+                       block_stage = BLOCK_FLUSH_RESERVED;
+                       protected = allocated_extent_slum_size(flush_pos, oid,
+                                                              index, width);
+                       if (protected == 0) {
+                               flush_pos->state = POS_INVALID;
+                               flush_pos->pos_in_unit = 0;
+                               return 0;
+                       }
+               } else {
+                       block_stage = BLOCK_UNALLOCATED;
+                       protected = width;
+               }
+
+               /*
+                * look at previous unit if possible. If it is allocated, make
+                * preceder more precise
+                */
+               if (coord->unit_pos &&
+                   (state_of_extent(ext - 1) == ALLOCATED_EXTENT))
+                       reiser4_pos_hint(flush_pos)->blk =
+                               extent_get_start(ext - 1) +
+                               extent_get_width(ext - 1);
+
+               /* allocate new block numbers for protected nodes */
+               extent_allocate_blocks(reiser4_pos_hint(flush_pos),
+                                      protected,
+                                      &first_allocated, &allocated,
+                                      block_stage);
+
+               /* prepare extent which will be copied to left */
+               reiser4_set_extent(&copy_extent, first_allocated, allocated);
+
+               result = put_unit_to_end(left, &key, &copy_extent);
+               if (result == -E_NODE_FULL) {
+                       int target_block_stage;
+
+                       /* free blocks which were just allocated */
+                       target_block_stage =
+                           (state ==
+                            ALLOCATED_EXTENT) ? BLOCK_FLUSH_RESERVED :
+                           BLOCK_UNALLOCATED;
+                       reiser4_dealloc_blocks(&first_allocated, &allocated,
+                                              target_block_stage,
+                                              BA_PERMANENT);
+
+                       /* rewind the preceder. */
+                       flush_pos->preceder.blk = first_allocated;
+                       check_preceder(flush_pos->preceder.blk);
+
+                       return SQUEEZE_TARGET_FULL;
+               }
+
+               if (state == ALLOCATED_EXTENT) {
+                       /* free nodes which were relocated */
+                       reiser4_dealloc_blocks(&start, &allocated,
+                                              BLOCK_ALLOCATED, BA_DEFER);
+               }
+
+               /* assign new block numbers to protected nodes */
+               assign_real_blocknrs(flush_pos, oid, index, allocated,
+                                    first_allocated);
+
+               set_key_offset(&key,
+                              get_key_offset(&key) +
+                              (allocated << current_blocksize_bits));
+       } else {
+               /*
+                * overwrite: try to copy unit as it is to left neighbor and
+                * make all first not flushprepped nodes overwrite nodes
+                */
+               reiser4_set_extent(&copy_extent, start, width);
+               result = put_unit_to_end(left, &key, &copy_extent);
+               if (result == -E_NODE_FULL)
+                       return SQUEEZE_TARGET_FULL;
+
+               if (state != HOLE_EXTENT)
+                       mark_jnodes_overwrite(flush_pos, oid, index, width);
+               set_key_offset(&key,
+                              get_key_offset(&key) +
+                              (width << current_blocksize_bits));
+       }
+       *stop_key = key;
+       return SQUEEZE_CONTINUE;
+}
+
+int key_by_offset_extent(struct inode *inode, loff_t off, reiser4_key * key)
+{
+       return key_by_inode_and_offset_common(inode, off, key);
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/extent.h linux-2.6.20/fs/reiser4/plugin/item/extent.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/extent.h   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/extent.h        2007-05-06 14:50:43.811010720 +0400
@@ -0,0 +1,231 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#ifndef __REISER4_EXTENT_H__
+#define __REISER4_EXTENT_H__
+
+/* on disk extent */
+typedef struct {
+       reiser4_dblock_nr start;
+       reiser4_dblock_nr width;
+} reiser4_extent;
+
+typedef struct extent_stat {
+       int unallocated_units;
+       int unallocated_blocks;
+       int allocated_units;
+       int allocated_blocks;
+       int hole_units;
+       int hole_blocks;
+} extent_stat;
+
+/* extents in an extent item can be either holes, or unallocated or allocated
+   extents */
+typedef enum {
+       HOLE_EXTENT,
+       UNALLOCATED_EXTENT,
+       ALLOCATED_EXTENT
+} extent_state;
+
+#define HOLE_EXTENT_START 0
+#define UNALLOCATED_EXTENT_START 1
+#define UNALLOCATED_EXTENT_START2 2
+
+typedef struct {
+       reiser4_block_nr pos_in_unit;
+       reiser4_block_nr width; /* width of current unit */
+       pos_in_node_t nr_units; /* number of units */
+       int ext_offset;         /* offset from the beginning of zdata() */
+       unsigned long expected_page;
+#if REISER4_DEBUG
+       reiser4_extent extent;
+#endif
+} extent_coord_extension_t;
+
+/* macros to set/get fields of on-disk extent */
+static inline reiser4_block_nr extent_get_start(const reiser4_extent * ext)
+{
+       return le64_to_cpu(ext->start);
+}
+
+static inline reiser4_block_nr extent_get_width(const reiser4_extent * ext)
+{
+       return le64_to_cpu(ext->width);
+}
+
+extern __u64 reiser4_current_block_count(void);
+
+static inline void
+extent_set_start(reiser4_extent * ext, reiser4_block_nr start)
+{
+       cassert(sizeof(ext->start) == 8);
+       assert("nikita-2510",
+              ergo(start > 1, start < reiser4_current_block_count()));
+       put_unaligned(cpu_to_le64(start), &ext->start);
+}
+
+static inline void
+extent_set_width(reiser4_extent * ext, reiser4_block_nr width)
+{
+       cassert(sizeof(ext->width) == 8);
+       assert("", width > 0);
+       put_unaligned(cpu_to_le64(width), &ext->width);
+       assert("nikita-2511",
+              ergo(extent_get_start(ext) > 1,
+                   extent_get_start(ext) + width <=
+                   reiser4_current_block_count()));
+}
+
+#define extent_item(coord)                                     \
+({                                                             \
+       assert("nikita-3143", item_is_extent(coord));           \
+       ((reiser4_extent *)item_body_by_coord (coord));         \
+})
+
+#define extent_by_coord(coord)                                 \
+({                                                             \
+       assert("nikita-3144", item_is_extent(coord));           \
+       (extent_item (coord) + (coord)->unit_pos);              \
+})
+
+#define width_by_coord(coord)                                  \
+({                                                             \
+       assert("nikita-3145", item_is_extent(coord));           \
+       extent_get_width (extent_by_coord(coord));              \
+})
+
+struct carry_cut_data;
+struct carry_kill_data;
+
+/* plugin->u.item.b.* */
+reiser4_key *max_key_inside_extent(const coord_t *, reiser4_key *);
+int can_contain_key_extent(const coord_t * coord, const reiser4_key * key,
+                          const reiser4_item_data *);
+int mergeable_extent(const coord_t * p1, const coord_t * p2);
+pos_in_node_t nr_units_extent(const coord_t *);
+lookup_result lookup_extent(const reiser4_key *, lookup_bias, coord_t *);
+void init_coord_extent(coord_t *);
+int init_extent(coord_t *, reiser4_item_data *);
+int paste_extent(coord_t *, reiser4_item_data *, carry_plugin_info *);
+int can_shift_extent(unsigned free_space,
+                    coord_t * source, znode * target, shift_direction,
+                    unsigned *size, unsigned want);
+void copy_units_extent(coord_t * target, coord_t * source, unsigned from,
+                      unsigned count, shift_direction where_is_free_space,
+                      unsigned free_space);
+int kill_hook_extent(const coord_t *, pos_in_node_t from, pos_in_node_t count,
+                    struct carry_kill_data *);
+int create_hook_extent(const coord_t * coord, void *arg);
+int cut_units_extent(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                    struct carry_cut_data *, reiser4_key * smallest_removed,
+                    reiser4_key * new_first);
+int kill_units_extent(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                     struct carry_kill_data *, reiser4_key * smallest_removed,
+                     reiser4_key * new_first);
+reiser4_key *unit_key_extent(const coord_t *, reiser4_key *);
+reiser4_key *max_unit_key_extent(const coord_t *, reiser4_key *);
+void print_extent(const char *, coord_t *);
+int utmost_child_extent(const coord_t * coord, sideof side, jnode ** child);
+int utmost_child_real_block_extent(const coord_t * coord, sideof side,
+                                  reiser4_block_nr * block);
+void item_stat_extent(const coord_t * coord, void *vp);
+int reiser4_check_extent(const coord_t * coord, const char **error);
+
+/* plugin->u.item.s.file.* */
+ssize_t reiser4_write_extent(struct file *, const char __user *,
+                            size_t, loff_t *);
+int reiser4_read_extent(struct file *, flow_t *, hint_t *);
+int reiser4_readpage_extent(void *, struct page *);
+int reiser4_do_readpage_extent(reiser4_extent*, reiser4_block_nr, struct page*);
+reiser4_key *append_key_extent(const coord_t *, reiser4_key *);
+void init_coord_extension_extent(uf_coord_t *, loff_t offset);
+int get_block_address_extent(const coord_t *, sector_t block,
+                            sector_t * result);
+
+/* these are used in flush.c
+   FIXME-VS: should they be somewhere in item_plugin? */
+int allocate_extent_item_in_place(coord_t *, lock_handle *, flush_pos_t * pos);
+int allocate_and_copy_extent(znode * left, coord_t * right, flush_pos_t * pos,
+                            reiser4_key * stop_key);
+
+int extent_is_unallocated(const coord_t * item);       /* True if this extent is unallocated (i.e., not a hole, not allocated). */
+__u64 extent_unit_index(const coord_t * item); /* Block offset of this unit. */
+__u64 extent_unit_width(const coord_t * item); /* Number of blocks in this unit. */
+
+/* plugin->u.item.f. */
+int reiser4_scan_extent(flush_scan * scan);
+extern int key_by_offset_extent(struct inode *, loff_t, reiser4_key *);
+
+reiser4_item_data *init_new_extent(reiser4_item_data * data, void *ext_unit,
+                                  int nr_extents);
+reiser4_block_nr reiser4_extent_size(const coord_t * coord, pos_in_node_t nr);
+extent_state state_of_extent(reiser4_extent * ext);
+void reiser4_set_extent(reiser4_extent *, reiser4_block_nr start,
+                       reiser4_block_nr width);
+int reiser4_update_extent(struct inode *, jnode *, loff_t pos,
+                         int *plugged_hole);
+
+#include "../../coord.h"
+#include "../../lock.h"
+#include "../../tap.h"
+
+struct replace_handle {
+       /* these are to be set before calling reiser4_replace_extent */
+       coord_t *coord;
+       lock_handle *lh;
+       reiser4_key key;
+       reiser4_key *pkey;
+       reiser4_extent overwrite;
+       reiser4_extent new_extents[2];
+       int nr_new_extents;
+       unsigned flags;
+
+       /* these are used by reiser4_replace_extent */
+       reiser4_item_data item;
+       coord_t coord_after;
+       lock_handle lh_after;
+       tap_t watch;
+       reiser4_key paste_key;
+#if REISER4_DEBUG
+       reiser4_extent orig_ext;
+       reiser4_key tmp;
+#endif
+};
+
+/* this structure is kmalloced before calling make_extent to avoid excessive
+   stack consumption on plug_hole->reiser4_replace_extent */
+struct make_extent_handle {
+       uf_coord_t *uf_coord;
+       reiser4_block_nr blocknr;
+       int created;
+       struct inode *inode;
+       union {
+               struct {
+               } append;
+               struct replace_handle replace;
+       } u;
+};
+
+int reiser4_replace_extent(struct replace_handle *,
+                          int return_inserted_position);
+lock_handle *znode_lh(znode *);
+
+/* the reiser4 repacker support */
+struct repacker_cursor;
+extern int process_extent_backward_for_repacking(tap_t *,
+                                                struct repacker_cursor *);
+extern int mark_extent_for_repacking(tap_t *, int);
+
+#define coord_by_uf_coord(uf_coord) (&((uf_coord)->coord))
+#define ext_coord_by_uf_coord(uf_coord) (&((uf_coord)->extension.extent))
+
+/* __REISER4_EXTENT_H__ */
+#endif
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/extent_item_ops.c linux-2.6.20/fs/reiser4/plugin/item/extent_item_ops.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/extent_item_ops.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/extent_item_ops.c       2007-05-06 14:50:43.815011970 +0400
@@ -0,0 +1,889 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "item.h"
+#include "../../inode.h"
+#include "../../tree_walk.h"   /* check_sibling_list() */
+#include "../../page_cache.h"
+#include "../../carry.h"
+
+#include <linux/quotaops.h>
+
+/* item_plugin->b.max_key_inside */
+reiser4_key *max_key_inside_extent(const coord_t * coord, reiser4_key * key)
+{
+       item_key_by_coord(coord, key);
+       set_key_offset(key, get_key_offset(reiser4_max_key()));
+       return key;
+}
+
+/* item_plugin->b.can_contain_key
+   this checks whether @key of @data is matching to position set by @coord */
+int
+can_contain_key_extent(const coord_t * coord, const reiser4_key * key,
+                      const reiser4_item_data * data)
+{
+       reiser4_key item_key;
+
+       if (item_plugin_by_coord(coord) != data->iplug)
+               return 0;
+
+       item_key_by_coord(coord, &item_key);
+       if (get_key_locality(key) != get_key_locality(&item_key) ||
+           get_key_objectid(key) != get_key_objectid(&item_key) ||
+           get_key_ordering(key) != get_key_ordering(&item_key))
+               return 0;
+
+       return 1;
+}
+
+/* item_plugin->b.mergeable
+   first item is of extent type */
+/* Audited by: green(2002.06.13) */
+int mergeable_extent(const coord_t * p1, const coord_t * p2)
+{
+       reiser4_key key1, key2;
+
+       assert("vs-299", item_id_by_coord(p1) == EXTENT_POINTER_ID);
+       /* FIXME-VS: Which is it? Assert or return 0 */
+       if (item_id_by_coord(p2) != EXTENT_POINTER_ID) {
+               return 0;
+       }
+
+       item_key_by_coord(p1, &key1);
+       item_key_by_coord(p2, &key2);
+       if (get_key_locality(&key1) != get_key_locality(&key2) ||
+           get_key_objectid(&key1) != get_key_objectid(&key2) ||
+           get_key_ordering(&key1) != get_key_ordering(&key2) ||
+           get_key_type(&key1) != get_key_type(&key2))
+               return 0;
+       if (get_key_offset(&key1) +
+           reiser4_extent_size(p1, nr_units_extent(p1)) !=
+           get_key_offset(&key2))
+               return 0;
+       return 1;
+}
+
+/* item_plugin->b.nr_units */
+pos_in_node_t nr_units_extent(const coord_t * coord)
+{
+       /* length of extent item has to be multiple of extent size */
+       assert("vs-1424",
+              (item_length_by_coord(coord) % sizeof(reiser4_extent)) == 0);
+       return item_length_by_coord(coord) / sizeof(reiser4_extent);
+}
+
+/* item_plugin->b.lookup */
+lookup_result
+lookup_extent(const reiser4_key * key, lookup_bias bias UNUSED_ARG,
+             coord_t * coord)
+{                              /* znode and item_pos are
+                                  set to an extent item to
+                                  look through */
+       reiser4_key item_key;
+       reiser4_block_nr lookuped, offset;
+       unsigned i, nr_units;
+       reiser4_extent *ext;
+       unsigned blocksize;
+       unsigned char blocksize_bits;
+
+       item_key_by_coord(coord, &item_key);
+       offset = get_key_offset(&item_key);
+
+       /* key we are looking for must be greater than key of item @coord */
+       assert("vs-414", keygt(key, &item_key));
+
+       assert("umka-99945",
+              !keygt(key, max_key_inside_extent(coord, &item_key)));
+
+       ext = extent_item(coord);
+       assert("vs-1350", (char *)ext == (zdata(coord->node) + coord->offset));
+
+       blocksize = current_blocksize;
+       blocksize_bits = current_blocksize_bits;
+
+       /* offset we are looking for */
+       lookuped = get_key_offset(key);
+
+       nr_units = nr_units_extent(coord);
+       /* go through all extents until the one which address given offset */
+       for (i = 0; i < nr_units; i++, ext++) {
+               offset += (extent_get_width(ext) << blocksize_bits);
+               if (offset > lookuped) {
+                       /* desired byte is somewhere in this extent */
+                       coord->unit_pos = i;
+                       coord->between = AT_UNIT;
+                       return CBK_COORD_FOUND;
+               }
+       }
+
+       /* set coord after last unit */
+       coord->unit_pos = nr_units - 1;
+       coord->between = AFTER_UNIT;
+       return CBK_COORD_FOUND;
+}
+
+/* item_plugin->b.paste
+   item @coord is set to has been appended with @data->length of free
+   space. data->data contains data to be pasted into the item in position
+   @coord->in_item.unit_pos. It must fit into that free space.
+   @coord must be set between units.
+*/
+int
+paste_extent(coord_t * coord, reiser4_item_data * data,
+            carry_plugin_info * info UNUSED_ARG)
+{
+       unsigned old_nr_units;
+       reiser4_extent *ext;
+       int item_length;
+
+       ext = extent_item(coord);
+       item_length = item_length_by_coord(coord);
+       old_nr_units = (item_length - data->length) / sizeof(reiser4_extent);
+
+       /* this is also used to copy extent into newly created item, so
+          old_nr_units could be 0 */
+       assert("vs-260", item_length >= data->length);
+
+       /* make sure that coord is set properly */
+       assert("vs-35",
+              ((!coord_is_existing_unit(coord))
+               || (!old_nr_units && !coord->unit_pos)));
+
+       /* first unit to be moved */
+       switch (coord->between) {
+       case AFTER_UNIT:
+               coord->unit_pos++;
+       case BEFORE_UNIT:
+               coord->between = AT_UNIT;
+               break;
+       case AT_UNIT:
+               assert("vs-331", !old_nr_units && !coord->unit_pos);
+               break;
+       default:
+               impossible("vs-330", "coord is set improperly");
+       }
+
+       /* prepare space for new units */
+       memmove(ext + coord->unit_pos + data->length / sizeof(reiser4_extent),
+               ext + coord->unit_pos,
+               (old_nr_units - coord->unit_pos) * sizeof(reiser4_extent));
+
+       /* copy new data from kernel space */
+       assert("vs-556", data->user == 0);
+       memcpy(ext + coord->unit_pos, data->data, (unsigned)data->length);
+
+       /* after paste @coord is set to first of pasted units */
+       assert("vs-332", coord_is_existing_unit(coord));
+       assert("vs-333",
+              !memcmp(data->data, extent_by_coord(coord),
+                      (unsigned)data->length));
+       return 0;
+}
+
+/* item_plugin->b.can_shift */
+int
+can_shift_extent(unsigned free_space, coord_t * source,
+                znode * target UNUSED_ARG, shift_direction pend UNUSED_ARG,
+                unsigned *size, unsigned want)
+{
+       *size = item_length_by_coord(source);
+       if (*size > free_space)
+               /* never split a unit of extent item */
+               *size = free_space - free_space % sizeof(reiser4_extent);
+
+       /* we can shift *size bytes, calculate how many do we want to shift */
+       if (*size > want * sizeof(reiser4_extent))
+               *size = want * sizeof(reiser4_extent);
+
+       if (*size % sizeof(reiser4_extent) != 0)
+               impossible("vs-119", "Wrong extent size: %i %zd", *size,
+                          sizeof(reiser4_extent));
+       return *size / sizeof(reiser4_extent);
+
+}
+
+/* item_plugin->b.copy_units */
+void
+copy_units_extent(coord_t * target, coord_t * source,
+                 unsigned from, unsigned count,
+                 shift_direction where_is_free_space, unsigned free_space)
+{
+       char *from_ext, *to_ext;
+
+       assert("vs-217", free_space == count * sizeof(reiser4_extent));
+
+       from_ext = item_body_by_coord(source);
+       to_ext = item_body_by_coord(target);
+
+       if (where_is_free_space == SHIFT_LEFT) {
+               assert("vs-215", from == 0);
+
+               /* At this moment, item length was already updated in the item
+                  header by shifting code, hence nr_units_extent() will
+                  return "new" number of units---one we obtain after copying
+                  units.
+                */
+               to_ext +=
+                   (nr_units_extent(target) - count) * sizeof(reiser4_extent);
+       } else {
+               reiser4_key key;
+               coord_t coord;
+
+               assert("vs-216",
+                      from + count == coord_last_unit_pos(source) + 1);
+
+               from_ext += item_length_by_coord(source) - free_space;
+
+               /* new units are inserted before first unit in an item,
+                  therefore, we have to update item key */
+               coord = *source;
+               coord.unit_pos = from;
+               unit_key_extent(&coord, &key);
+
+               node_plugin_by_node(target->node)->update_item_key(target, &key,
+                                                                  NULL /*info */);
+       }
+
+       memcpy(to_ext, from_ext, free_space);
+}
+
+/* item_plugin->b.create_hook
+   @arg is znode of leaf node for which we need to update right delimiting key */
+int create_hook_extent(const coord_t * coord, void *arg)
+{
+       coord_t *child_coord;
+       znode *node;
+       reiser4_key key;
+       reiser4_tree *tree;
+
+       if (!arg)
+               return 0;
+
+       child_coord = arg;
+       tree = znode_get_tree(coord->node);
+
+       assert("nikita-3246", znode_get_level(child_coord->node) == LEAF_LEVEL);
+
+       write_lock_tree(tree);
+       write_lock_dk(tree);
+       /* find a node on the left level for which right delimiting key has to
+          be updated */
+       if (coord_wrt(child_coord) == COORD_ON_THE_LEFT) {
+               assert("vs-411", znode_is_left_connected(child_coord->node));
+               node = child_coord->node->left;
+       } else {
+               assert("vs-412", coord_wrt(child_coord) == COORD_ON_THE_RIGHT);
+               node = child_coord->node;
+               assert("nikita-3314", node != NULL);
+       }
+
+       if (node != NULL) {
+               znode_set_rd_key(node, item_key_by_coord(coord, &key));
+
+               assert("nikita-3282", check_sibling_list(node));
+               /* break sibling links */
+               if (ZF_ISSET(node, JNODE_RIGHT_CONNECTED) && node->right) {
+                       ON_DEBUG(node->right->left_version =
+                                atomic_inc_return(&delim_key_version);
+                                node->right_version =
+                                atomic_inc_return(&delim_key_version););
+
+                       node->right->left = NULL;
+                       node->right = NULL;
+               }
+       }
+       write_unlock_dk(tree);
+       write_unlock_tree(tree);
+       return 0;
+}
+
+#define ITEM_TAIL_KILLED 0
+#define ITEM_HEAD_KILLED 1
+#define ITEM_KILLED 2
+
+/* item_plugin->b.kill_hook
+   this is called when @count units starting from @from-th one are going to be removed
+   */
+int
+kill_hook_extent(const coord_t * coord, pos_in_node_t from, pos_in_node_t count,
+                struct carry_kill_data *kdata)
+{
+       reiser4_extent *ext;
+       reiser4_block_nr start, length;
+       const reiser4_key *pfrom_key, *pto_key;
+       struct inode *inode;
+       reiser4_tree *tree;
+       pgoff_t from_off, to_off, offset, skip;
+       int retval;
+
+       /* these are located in memory kmalloc-ed by kill_node_content */
+       reiser4_key *min_item_key, *max_item_key, *from_key, *to_key, *key;
+       coord_t *dup, *next;
+
+       assert("zam-811", znode_is_write_locked(coord->node));
+       assert("nikita-3315", kdata != NULL);
+       assert("vs-34", kdata->buf != NULL);
+
+       /* map structures to kdata->buf */
+       min_item_key = (reiser4_key *) (kdata->buf);
+       max_item_key = min_item_key + 1;
+       from_key = max_item_key + 1;
+       to_key = from_key + 1;
+       key = to_key + 1;
+       dup = (coord_t *) (key + 1);
+       next = dup + 1;
+
+       item_key_by_coord(coord, min_item_key);
+       max_item_key_by_coord(coord, max_item_key);
+
+       if (kdata->params.from_key) {
+               pfrom_key = kdata->params.from_key;
+               pto_key = kdata->params.to_key;
+       } else {
+               assert("vs-1549", from == coord->unit_pos);
+               unit_key_by_coord(coord, from_key);
+               pfrom_key = from_key;
+
+               coord_dup(dup, coord);
+               dup->unit_pos = from + count - 1;
+               max_unit_key_by_coord(dup, to_key);
+               pto_key = to_key;
+       }
+
+       if (!keylt(pto_key, max_item_key)) {
+               if (!keygt(pfrom_key, min_item_key)) {
+                       znode *left, *right;
+
+                       /* item is to be removed completely */
+                       assert("nikita-3316", kdata->left != NULL
+                              && kdata->right != NULL);
+
+                       left = kdata->left->node;
+                       right = kdata->right->node;
+
+                       tree = current_tree;
+                       /* we have to do two things:
+                        *
+                        *     1. link left and right formatted neighbors of
+                        *        extent being removed, and
+                        *
+                        *     2. update their delimiting keys.
+                        *
+                        * atomicity of these operations is protected by
+                        * taking dk-lock and tree-lock.
+                        */
+                       /* if neighbors of item being removed are znodes -
+                        * link them */
+                       write_lock_tree(tree);
+                       write_lock_dk(tree);
+                       link_left_and_right(left, right);
+                       if (left) {
+                               /* update right delimiting key of left
+                                * neighbor of extent item */
+                               /*coord_t next;
+                                  reiser4_key key; */
+
+                               coord_dup(next, coord);
+
+                               if (coord_next_item(next))
+                                       *key = *znode_get_rd_key(coord->node);
+                               else
+                                       item_key_by_coord(next, key);
+                               znode_set_rd_key(left, key);
+                       }
+                       write_unlock_dk(tree);
+                       write_unlock_tree(tree);
+
+                       from_off =
+                           get_key_offset(min_item_key) >> PAGE_CACHE_SHIFT;
+                       to_off =
+                           (get_key_offset(max_item_key) +
+                            1) >> PAGE_CACHE_SHIFT;
+                       retval = ITEM_KILLED;
+               } else {
+                       /* tail of item is to be removed */
+                       from_off =
+                           (get_key_offset(pfrom_key) + PAGE_CACHE_SIZE -
+                            1) >> PAGE_CACHE_SHIFT;
+                       to_off =
+                           (get_key_offset(max_item_key) +
+                            1) >> PAGE_CACHE_SHIFT;
+                       retval = ITEM_TAIL_KILLED;
+               }
+       } else {
+               /* head of item is to be removed */
+               assert("vs-1571", keyeq(pfrom_key, min_item_key));
+               assert("vs-1572",
+                      (get_key_offset(pfrom_key) & (PAGE_CACHE_SIZE - 1)) ==
+                      0);
+               assert("vs-1573",
+                      ((get_key_offset(pto_key) + 1) & (PAGE_CACHE_SIZE -
+                                                        1)) == 0);
+
+               if (kdata->left->node) {
+                       /* update right delimiting key of left neighbor of extent item */
+                       /*reiser4_key key; */
+
+                       *key = *pto_key;
+                       set_key_offset(key, get_key_offset(pto_key) + 1);
+
+                       write_lock_dk(current_tree);
+                       znode_set_rd_key(kdata->left->node, key);
+                       write_unlock_dk(current_tree);
+               }
+
+               from_off = get_key_offset(pfrom_key) >> PAGE_CACHE_SHIFT;
+               to_off = (get_key_offset(pto_key) + 1) >> PAGE_CACHE_SHIFT;
+               retval = ITEM_HEAD_KILLED;
+       }
+
+       inode = kdata->inode;
+       assert("vs-1545", inode != NULL);
+       if (inode != NULL)
+               /* take care of pages and jnodes corresponding to part of item being killed */
+               reiser4_invalidate_pages(inode->i_mapping, from_off,
+                                        to_off - from_off,
+                                        kdata->params.truncate);
+
+       ext = extent_item(coord) + from;
+       offset =
+           (get_key_offset(min_item_key) +
+            reiser4_extent_size(coord, from)) >> PAGE_CACHE_SHIFT;
+
+       assert("vs-1551", from_off >= offset);
+       assert("vs-1552", from_off - offset <= extent_get_width(ext));
+       skip = from_off - offset;
+       offset = from_off;
+
+       while (offset < to_off) {
+               length = extent_get_width(ext) - skip;
+               if (state_of_extent(ext) == HOLE_EXTENT) {
+                       skip = 0;
+                       offset += length;
+                       ext++;
+                       continue;
+               }
+
+               if (offset + length > to_off) {
+                       length = to_off - offset;
+               }
+
+               DQUOT_FREE_BLOCK_NODIRTY(inode, length);
+
+               if (state_of_extent(ext) == UNALLOCATED_EXTENT) {
+                       /* some jnodes corresponding to this unallocated extent */
+                       fake_allocated2free(length, 0 /* unformatted */ );
+
+                       skip = 0;
+                       offset += length;
+                       ext++;
+                       continue;
+               }
+
+               assert("vs-1218", state_of_extent(ext) == ALLOCATED_EXTENT);
+
+               if (length != 0) {
+                       start = extent_get_start(ext) + skip;
+
+                       /* BA_DEFER bit parameter is turned on because blocks which get freed are not safe to be freed
+                          immediately */
+                       reiser4_dealloc_blocks(&start, &length,
+                                              0 /* not used */ ,
+                                              BA_DEFER
+                                              /* unformatted with defer */ );
+               }
+               skip = 0;
+               offset += length;
+               ext++;
+       }
+       return retval;
+}
+
+/* item_plugin->b.kill_units */
+int
+kill_units_extent(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                 struct carry_kill_data *kdata, reiser4_key * smallest_removed,
+                 reiser4_key * new_first)
+{
+       reiser4_extent *ext;
+       reiser4_key item_key;
+       pos_in_node_t count;
+       reiser4_key from_key, to_key;
+       const reiser4_key *pfrom_key, *pto_key;
+       loff_t off;
+       int result;
+
+       assert("vs-1541",
+              ((kdata->params.from_key == NULL && kdata->params.to_key == NULL)
+               || (kdata->params.from_key != NULL
+                   && kdata->params.to_key != NULL)));
+
+       if (kdata->params.from_key) {
+               pfrom_key = kdata->params.from_key;
+               pto_key = kdata->params.to_key;
+       } else {
+               coord_t dup;
+
+               /* calculate key range of kill */
+               assert("vs-1549", from == coord->unit_pos);
+               unit_key_by_coord(coord, &from_key);
+               pfrom_key = &from_key;
+
+               coord_dup(&dup, coord);
+               dup.unit_pos = to;
+               max_unit_key_by_coord(&dup, &to_key);
+               pto_key = &to_key;
+       }
+
+       item_key_by_coord(coord, &item_key);
+
+#if REISER4_DEBUG
+       {
+               reiser4_key max_item_key;
+
+               max_item_key_by_coord(coord, &max_item_key);
+
+               if (new_first) {
+                       /* head of item is to be cut */
+                       assert("vs-1542", keyeq(pfrom_key, &item_key));
+                       assert("vs-1538", keylt(pto_key, &max_item_key));
+               } else {
+                       /* tail of item is to be cut */
+                       assert("vs-1540", keygt(pfrom_key, &item_key));
+                       assert("vs-1543", !keylt(pto_key, &max_item_key));
+               }
+       }
+#endif
+
+       if (smallest_removed)
+               *smallest_removed = *pfrom_key;
+
+       if (new_first) {
+               /* item head is cut. Item key will change. This new key is calculated here */
+               assert("vs-1556",
+                      (get_key_offset(pto_key) & (PAGE_CACHE_SIZE - 1)) ==
+                      (PAGE_CACHE_SIZE - 1));
+               *new_first = *pto_key;
+               set_key_offset(new_first, get_key_offset(new_first) + 1);
+       }
+
+       count = to - from + 1;
+       result = kill_hook_extent(coord, from, count, kdata);
+       if (result == ITEM_TAIL_KILLED) {
+               assert("vs-1553",
+                      get_key_offset(pfrom_key) >=
+                      get_key_offset(&item_key) +
+                      reiser4_extent_size(coord, from));
+               off =
+                   get_key_offset(pfrom_key) -
+                       (get_key_offset(&item_key) +
+                        reiser4_extent_size(coord, from));
+               if (off) {
+                       /* unit @from is to be cut partially. Its width decreases */
+                       ext = extent_item(coord) + from;
+                       extent_set_width(ext,
+                                        (off + PAGE_CACHE_SIZE -
+                                         1) >> PAGE_CACHE_SHIFT);
+                       count--;
+               }
+       } else {
+               __u64 max_to_offset;
+               __u64 rest;
+
+               assert("vs-1575", result == ITEM_HEAD_KILLED);
+               assert("", from == 0);
+               assert("",
+                      ((get_key_offset(pto_key) + 1) & (PAGE_CACHE_SIZE -
+                                                        1)) == 0);
+               assert("",
+                      get_key_offset(pto_key) + 1 >
+                      get_key_offset(&item_key) +
+                      reiser4_extent_size(coord, to));
+               max_to_offset =
+                   get_key_offset(&item_key) +
+                       reiser4_extent_size(coord, to + 1) - 1;
+               assert("", get_key_offset(pto_key) <= max_to_offset);
+
+               rest =
+                   (max_to_offset -
+                    get_key_offset(pto_key)) >> PAGE_CACHE_SHIFT;
+               if (rest) {
+                       /* unit @to is to be cut partially */
+                       ext = extent_item(coord) + to;
+
+                       assert("", extent_get_width(ext) > rest);
+
+                       if (state_of_extent(ext) == ALLOCATED_EXTENT)
+                               extent_set_start(ext,
+                                                extent_get_start(ext) +
+                                                (extent_get_width(ext) -
+                                                 rest));
+
+                       extent_set_width(ext, rest);
+                       count--;
+               }
+       }
+       return count * sizeof(reiser4_extent);
+}
+
+/* item_plugin->b.cut_units
+   this is too similar to kill_units_extent */
+int
+cut_units_extent(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+                struct carry_cut_data *cdata, reiser4_key * smallest_removed,
+                reiser4_key * new_first)
+{
+       reiser4_extent *ext;
+       reiser4_key item_key;
+       pos_in_node_t count;
+       reiser4_key from_key, to_key;
+       const reiser4_key *pfrom_key, *pto_key;
+       loff_t off;
+
+       assert("vs-1541",
+              ((cdata->params.from_key == NULL && cdata->params.to_key == NULL)
+               || (cdata->params.from_key != NULL
+                   && cdata->params.to_key != NULL)));
+
+       if (cdata->params.from_key) {
+               pfrom_key = cdata->params.from_key;
+               pto_key = cdata->params.to_key;
+       } else {
+               coord_t dup;
+
+               /* calculate key range of kill */
+               coord_dup(&dup, coord);
+               dup.unit_pos = from;
+               unit_key_by_coord(&dup, &from_key);
+
+               dup.unit_pos = to;
+               max_unit_key_by_coord(&dup, &to_key);
+
+               pfrom_key = &from_key;
+               pto_key = &to_key;
+       }
+
+       assert("vs-1555",
+              (get_key_offset(pfrom_key) & (PAGE_CACHE_SIZE - 1)) == 0);
+       assert("vs-1556",
+              (get_key_offset(pto_key) & (PAGE_CACHE_SIZE - 1)) ==
+              (PAGE_CACHE_SIZE - 1));
+
+       item_key_by_coord(coord, &item_key);
+
+#if REISER4_DEBUG
+       {
+               reiser4_key max_item_key;
+
+               assert("vs-1584",
+                      get_key_locality(pfrom_key) ==
+                      get_key_locality(&item_key));
+               assert("vs-1585",
+                      get_key_type(pfrom_key) == get_key_type(&item_key));
+               assert("vs-1586",
+                      get_key_objectid(pfrom_key) ==
+                      get_key_objectid(&item_key));
+               assert("vs-1587",
+                      get_key_ordering(pfrom_key) ==
+                      get_key_ordering(&item_key));
+
+               max_item_key_by_coord(coord, &max_item_key);
+
+               if (new_first != NULL) {
+                       /* head of item is to be cut */
+                       assert("vs-1542", keyeq(pfrom_key, &item_key));
+                       assert("vs-1538", keylt(pto_key, &max_item_key));
+               } else {
+                       /* tail of item is to be cut */
+                       assert("vs-1540", keygt(pfrom_key, &item_key));
+                       assert("vs-1543", keyeq(pto_key, &max_item_key));
+               }
+       }
+#endif
+
+       if (smallest_removed)
+               *smallest_removed = *pfrom_key;
+
+       if (new_first) {
+               /* item head is cut. Item key will change. This new key is calculated here */
+               *new_first = *pto_key;
+               set_key_offset(new_first, get_key_offset(new_first) + 1);
+       }
+
+       count = to - from + 1;
+
+       assert("vs-1553",
+              get_key_offset(pfrom_key) >=
+              get_key_offset(&item_key) + reiser4_extent_size(coord, from));
+       off =
+           get_key_offset(pfrom_key) - (get_key_offset(&item_key) +
+                                        reiser4_extent_size(coord, from));
+       if (off) {
+               /* tail of unit @from is to be cut partially. Its width decreases */
+               assert("vs-1582", new_first == NULL);
+               ext = extent_item(coord) + from;
+               extent_set_width(ext, off >> PAGE_CACHE_SHIFT);
+               count--;
+       }
+
+       assert("vs-1554",
+              get_key_offset(pto_key) <=
+              get_key_offset(&item_key) +
+              reiser4_extent_size(coord, to + 1) - 1);
+       off =
+               (get_key_offset(&item_key) +
+                reiser4_extent_size(coord, to + 1) - 1) -
+               get_key_offset(pto_key);
+       if (off) {
+               /* @to_key is smaller than max key of unit @to. Unit @to will not be removed. It gets start increased
+                  and width decreased. */
+               assert("vs-1583", (off & (PAGE_CACHE_SIZE - 1)) == 0);
+               ext = extent_item(coord) + to;
+               if (state_of_extent(ext) == ALLOCATED_EXTENT)
+                       extent_set_start(ext,
+                                        extent_get_start(ext) +
+                                        (extent_get_width(ext) -
+                                         (off >> PAGE_CACHE_SHIFT)));
+
+               extent_set_width(ext, (off >> PAGE_CACHE_SHIFT));
+               count--;
+       }
+       return count * sizeof(reiser4_extent);
+}
+
+/* item_plugin->b.unit_key */
+reiser4_key *unit_key_extent(const coord_t * coord, reiser4_key * key)
+{
+       assert("vs-300", coord_is_existing_unit(coord));
+
+       item_key_by_coord(coord, key);
+       set_key_offset(key,
+                      (get_key_offset(key) +
+                       reiser4_extent_size(coord, coord->unit_pos)));
+
+       return key;
+}
+
+/* item_plugin->b.max_unit_key */
+reiser4_key *max_unit_key_extent(const coord_t * coord, reiser4_key * key)
+{
+       assert("vs-300", coord_is_existing_unit(coord));
+
+       item_key_by_coord(coord, key);
+       set_key_offset(key,
+                      (get_key_offset(key) +
+                       reiser4_extent_size(coord, coord->unit_pos + 1) - 1));
+       return key;
+}
+
+/* item_plugin->b.estimate
+   item_plugin->b.item_data_by_flow */
+
+#if REISER4_DEBUG
+
+/* item_plugin->b.check
+   used for debugging, every item should have here the most complete
+   possible check of the consistency of the item that the inventor can
+   construct
+*/
+int reiser4_check_extent(const coord_t * coord /* coord of item to check */,
+                        const char **error /* where to store error message */)
+{
+       reiser4_extent *ext, *first;
+       unsigned i, j;
+       reiser4_block_nr start, width, blk_cnt;
+       unsigned num_units;
+       reiser4_tree *tree;
+       oid_t oid;
+       reiser4_key key;
+       coord_t scan;
+
+       assert("vs-933", REISER4_DEBUG);
+
+       if (znode_get_level(coord->node) != TWIG_LEVEL) {
+               *error = "Extent on the wrong level";
+               return -1;
+       }
+       if (item_length_by_coord(coord) % sizeof(reiser4_extent) != 0) {
+               *error = "Wrong item size";
+               return -1;
+       }
+       ext = first = extent_item(coord);
+       blk_cnt = reiser4_block_count(reiser4_get_current_sb());
+       num_units = coord_num_units(coord);
+       tree = znode_get_tree(coord->node);
+       item_key_by_coord(coord, &key);
+       oid = get_key_objectid(&key);
+       coord_dup(&scan, coord);
+
+       for (i = 0; i < num_units; ++i, ++ext) {
+               __u64 index;
+
+               scan.unit_pos = i;
+               index = extent_unit_index(&scan);
+
+#if 0
+               /* check that all jnodes are present for the unallocated
+                * extent */
+               if (state_of_extent(ext) == UNALLOCATED_EXTENT) {
+                       for (j = 0; j < extent_get_width(ext); j++) {
+                               jnode *node;
+
+                               node = jlookup(tree, oid, index + j);
+                               if (node == NULL) {
+                                       print_coord("scan", &scan, 0);
+                                       *error = "Jnode missing";
+                                       return -1;
+                               }
+                               jput(node);
+                       }
+               }
+#endif
+
+               start = extent_get_start(ext);
+               if (start < 2)
+                       continue;
+               /* extent is allocated one */
+               width = extent_get_width(ext);
+               if (start >= blk_cnt) {
+                       *error = "Start too large";
+                       return -1;
+               }
+               if (start + width > blk_cnt) {
+                       *error = "End too large";
+                       return -1;
+               }
+               /* make sure that this extent does not overlap with other
+                  allocated extents extents */
+               for (j = 0; j < i; j++) {
+                       if (state_of_extent(first + j) != ALLOCATED_EXTENT)
+                               continue;
+                       if (!
+                           ((extent_get_start(ext) >=
+                             extent_get_start(first + j) +
+                             extent_get_width(first + j))
+                            || (extent_get_start(ext) +
+                                extent_get_width(ext) <=
+                                extent_get_start(first + j)))) {
+                               *error = "Extent overlaps with others";
+                               return -1;
+                       }
+               }
+
+       }
+
+       return 0;
+}
+
+#endif                         /* REISER4_DEBUG */
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/internal.c linux-2.6.20/fs/reiser4/plugin/item/internal.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/internal.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/internal.c      2007-05-06 14:50:43.815011970 +0400
@@ -0,0 +1,396 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Implementation of internal-item plugin methods. */
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "internal.h"
+#include "item.h"
+#include "../node/node.h"
+#include "../plugin.h"
+#include "../../jnode.h"
+#include "../../znode.h"
+#include "../../tree_walk.h"
+#include "../../tree_mod.h"
+#include "../../tree.h"
+#include "../../super.h"
+#include "../../block_alloc.h"
+
+/* see internal.h for explanation */
+
+/* plugin->u.item.b.mergeable */
+int mergeable_internal(const coord_t * p1 UNUSED_ARG /* first item */ ,
+                      const coord_t * p2 UNUSED_ARG /* second item */ )
+{
+       /* internal items are not mergeable */
+       return 0;
+}
+
+/* ->lookup() method for internal items */
+lookup_result lookup_internal(const reiser4_key * key /* key to look up */ ,
+                             lookup_bias bias UNUSED_ARG /* lookup bias */ ,
+                             coord_t * coord /* coord of item */ )
+{
+       reiser4_key ukey;
+
+       switch (keycmp(unit_key_by_coord(coord, &ukey), key)) {
+       default:
+               impossible("", "keycmp()?!");
+       case LESS_THAN:
+               /* FIXME-VS: AFTER_ITEM used to be here. But with new coord
+                  item plugin can not be taken using coord set this way */
+               assert("vs-681", coord->unit_pos == 0);
+               coord->between = AFTER_UNIT;
+       case EQUAL_TO:
+               return CBK_COORD_FOUND;
+       case GREATER_THAN:
+               return CBK_COORD_NOTFOUND;
+       }
+}
+
+/* return body of internal item at @coord */
+static internal_item_layout *internal_at(const coord_t * coord /* coord of
+                                                                * item */ )
+{
+       assert("nikita-607", coord != NULL);
+       assert("nikita-1650",
+              item_plugin_by_coord(coord) ==
+              item_plugin_by_id(NODE_POINTER_ID));
+       return (internal_item_layout *) item_body_by_coord(coord);
+}
+
+void reiser4_update_internal(const coord_t * coord,
+                            const reiser4_block_nr * blocknr)
+{
+       internal_item_layout *item = internal_at(coord);
+       assert("nikita-2959", reiser4_blocknr_is_sane(blocknr));
+
+       put_unaligned(cpu_to_le64(*blocknr), &item->pointer);
+}
+
+/* return child block number stored in the internal item at @coord */
+static reiser4_block_nr pointer_at(const coord_t * coord /* coord of item */ )
+{
+       assert("nikita-608", coord != NULL);
+       return le64_to_cpu(get_unaligned(&internal_at(coord)->pointer));
+}
+
+/* get znode pointed to by internal @item */
+static znode *znode_at(const coord_t * item /* coord of item */ ,
+                      znode * parent /* parent node */ )
+{
+       return child_znode(item, parent, 1, 0);
+}
+
+/* store pointer from internal item into "block". Implementation of
+    ->down_link() method */
+void down_link_internal(const coord_t * coord /* coord of item */ ,
+                       const reiser4_key * key UNUSED_ARG      /* key to get
+                                                                * pointer for */ ,
+                       reiser4_block_nr * block /* resulting block number */ )
+{
+       ON_DEBUG(reiser4_key item_key);
+
+       assert("nikita-609", coord != NULL);
+       assert("nikita-611", block != NULL);
+       assert("nikita-612", (key == NULL) ||
+              /* twig horrors */
+              (znode_get_level(coord->node) == TWIG_LEVEL)
+              || keyle(item_key_by_coord(coord, &item_key), key));
+
+       *block = pointer_at(coord);
+       assert("nikita-2960", reiser4_blocknr_is_sane(block));
+}
+
+/* Get the child's block number, or 0 if the block is unallocated. */
+int
+utmost_child_real_block_internal(const coord_t * coord, sideof side UNUSED_ARG,
+                                reiser4_block_nr * block)
+{
+       assert("jmacd-2059", coord != NULL);
+
+       *block = pointer_at(coord);
+       assert("nikita-2961", reiser4_blocknr_is_sane(block));
+
+       if (reiser4_blocknr_is_fake(block)) {
+               *block = 0;
+       }
+
+       return 0;
+}
+
+/* Return the child. */
+int
+utmost_child_internal(const coord_t * coord, sideof side UNUSED_ARG,
+                     jnode ** childp)
+{
+       reiser4_block_nr block = pointer_at(coord);
+       znode *child;
+
+       assert("jmacd-2059", childp != NULL);
+       assert("nikita-2962", reiser4_blocknr_is_sane(&block));
+
+       child = zlook(znode_get_tree(coord->node), &block);
+
+       if (IS_ERR(child)) {
+               return PTR_ERR(child);
+       }
+
+       *childp = ZJNODE(child);
+
+       return 0;
+}
+
+#if REISER4_DEBUG
+
+static void check_link(znode * left, znode * right)
+{
+       znode *scan;
+
+       for (scan = left; scan != right; scan = scan->right) {
+               if (ZF_ISSET(scan, JNODE_RIP))
+                       break;
+               if (znode_is_right_connected(scan) && scan->right != NULL) {
+                       if (ZF_ISSET(scan->right, JNODE_RIP))
+                               break;
+                       assert("nikita-3285",
+                              znode_is_left_connected(scan->right));
+                       assert("nikita-3265",
+                              ergo(scan != left,
+                                   ZF_ISSET(scan, JNODE_HEARD_BANSHEE)));
+                       assert("nikita-3284", scan->right->left == scan);
+               } else
+                       break;
+       }
+}
+
+int check__internal(const coord_t * coord, const char **error)
+{
+       reiser4_block_nr blk;
+       znode *child;
+       coord_t cpy;
+
+       blk = pointer_at(coord);
+       if (!reiser4_blocknr_is_sane(&blk)) {
+               *error = "Invalid pointer";
+               return -1;
+       }
+       coord_dup(&cpy, coord);
+       child = znode_at(&cpy, cpy.node);
+       if (child != NULL) {
+               znode *left_child;
+               znode *right_child;
+
+               left_child = right_child = NULL;
+
+               assert("nikita-3256", znode_invariant(child));
+               if (coord_prev_item(&cpy) == 0 && item_is_internal(&cpy)) {
+                       left_child = znode_at(&cpy, cpy.node);
+                       if (left_child != NULL) {
+                               read_lock_tree(znode_get_tree(child));
+                               check_link(left_child, child);
+                               read_unlock_tree(znode_get_tree(child));
+                               zput(left_child);
+                       }
+               }
+               coord_dup(&cpy, coord);
+               if (coord_next_item(&cpy) == 0 && item_is_internal(&cpy)) {
+                       right_child = znode_at(&cpy, cpy.node);
+                       if (right_child != NULL) {
+                               read_lock_tree(znode_get_tree(child));
+                               check_link(child, right_child);
+                               read_unlock_tree(znode_get_tree(child));
+                               zput(right_child);
+                       }
+               }
+               zput(child);
+       }
+       return 0;
+}
+
+#endif  /*  REISER4_DEBUG  */
+
+/* return true only if this item really points to "block" */
+/* Audited by: green(2002.06.14) */
+int has_pointer_to_internal(const coord_t * coord /* coord of item */ ,
+                           const reiser4_block_nr * block      /* block number to
+                                                                * check */ )
+{
+       assert("nikita-613", coord != NULL);
+       assert("nikita-614", block != NULL);
+
+       return pointer_at(coord) == *block;
+}
+
+/* hook called by ->create_item() method of node plugin after new internal
+   item was just created.
+
+   This is point where pointer to new node is inserted into tree. Initialize
+   parent pointer in child znode, insert child into sibling list and slum.
+
+*/
+int create_hook_internal(const coord_t * item /* coord of item */ ,
+                        void *arg /* child's left neighbor, if any */ )
+{
+       znode *child;
+       __u64 child_ptr;
+
+       assert("nikita-1252", item != NULL);
+       assert("nikita-1253", item->node != NULL);
+       assert("nikita-1181", znode_get_level(item->node) > LEAF_LEVEL);
+       assert("nikita-1450", item->unit_pos == 0);
+
+       /*
+        * preparing to item insertion build_child_ptr_data sets pointer to
+        * data to be inserted to jnode's blocknr which is in cpu byte
+        * order. Node's create_item simply copied those data. As result we
+        * have child pointer in cpu's byte order. Convert content of internal
+        * item to little endian byte order.
+        */
+       child_ptr = get_unaligned((__u64 *)item_body_by_coord(item));
+       reiser4_update_internal(item, &child_ptr);
+
+       child = znode_at(item, item->node);
+       if (child != NULL && !IS_ERR(child)) {
+               znode *left;
+               int result = 0;
+               reiser4_tree *tree;
+
+               left = arg;
+               tree = znode_get_tree(item->node);
+               write_lock_tree(tree);
+               write_lock_dk(tree);
+               assert("nikita-1400", (child->in_parent.node == NULL)
+                      || (znode_above_root(child->in_parent.node)));
+               ++item->node->c_count;
+               coord_to_parent_coord(item, &child->in_parent);
+               sibling_list_insert_nolock(child, left);
+
+               assert("nikita-3297", ZF_ISSET(child, JNODE_ORPHAN));
+               ZF_CLR(child, JNODE_ORPHAN);
+
+               if ((left != NULL) && !keyeq(znode_get_rd_key(left),
+                                            znode_get_rd_key(child))) {
+                       znode_set_rd_key(child, znode_get_rd_key(left));
+               }
+               write_unlock_dk(tree);
+               write_unlock_tree(tree);
+               zput(child);
+               return result;
+       } else {
+               if (child == NULL)
+                       child = ERR_PTR(-EIO);
+               return PTR_ERR(child);
+       }
+}
+
+/* hook called by ->cut_and_kill() method of node plugin just before internal
+   item is removed.
+
+   This is point where empty node is removed from the tree. Clear parent
+   pointer in child, and mark node for pending deletion.
+
+   Node will be actually deleted later and in several installations:
+
+    . when last lock on this node will be released, node will be removed from
+    the sibling list and its lock will be invalidated
+
+    . when last reference to this node will be dropped, bitmap will be updated
+    and node will be actually removed from the memory.
+
+*/
+int kill_hook_internal(const coord_t * item /* coord of item */ ,
+                      pos_in_node_t from UNUSED_ARG /* start unit */ ,
+                      pos_in_node_t count UNUSED_ARG /* stop unit */ ,
+                      struct carry_kill_data *p UNUSED_ARG)
+{
+       znode *child;
+
+       assert("nikita-1222", item != NULL);
+       assert("nikita-1224", from == 0);
+       assert("nikita-1225", count == 1);
+
+       child = znode_at(item, item->node);
+       if (IS_ERR(child))
+               return PTR_ERR(child);
+       else if (node_is_empty(child)) {
+               reiser4_tree *tree;
+
+               assert("nikita-1397", znode_is_write_locked(child));
+               assert("nikita-1398", child->c_count == 0);
+               assert("nikita-2546", ZF_ISSET(child, JNODE_HEARD_BANSHEE));
+
+               tree = znode_get_tree(item->node);
+               write_lock_tree(tree);
+               init_parent_coord(&child->in_parent, NULL);
+               --item->node->c_count;
+               write_unlock_tree(tree);
+               zput(child);
+               return 0;
+       } else {
+               warning("nikita-1223",
+                       "Cowardly refuse to remove link to non-empty node");
+               zput(child);
+               return RETERR(-EIO);
+       }
+}
+
+/* hook called by ->shift() node plugin method when iternal item was just
+   moved from one node to another.
+
+   Update parent pointer in child and c_counts in old and new parent
+
+*/
+int shift_hook_internal(const coord_t * item /* coord of item */ ,
+                       unsigned from UNUSED_ARG /* start unit */ ,
+                       unsigned count UNUSED_ARG /* stop unit */ ,
+                       znode * old_node /* old parent */ )
+{
+       znode *child;
+       znode *new_node;
+       reiser4_tree *tree;
+
+       assert("nikita-1276", item != NULL);
+       assert("nikita-1277", from == 0);
+       assert("nikita-1278", count == 1);
+       assert("nikita-1451", item->unit_pos == 0);
+
+       new_node = item->node;
+       assert("nikita-2132", new_node != old_node);
+       tree = znode_get_tree(item->node);
+       child = child_znode(item, old_node, 1, 0);
+       if (child == NULL)
+               return 0;
+       if (!IS_ERR(child)) {
+               write_lock_tree(tree);
+               ++new_node->c_count;
+               assert("nikita-1395", znode_parent(child) == old_node);
+               assert("nikita-1396", old_node->c_count > 0);
+               coord_to_parent_coord(item, &child->in_parent);
+               assert("nikita-1781", znode_parent(child) == new_node);
+               assert("nikita-1782",
+                      check_tree_pointer(item, child) == NS_FOUND);
+               --old_node->c_count;
+               write_unlock_tree(tree);
+               zput(child);
+               return 0;
+       } else
+               return PTR_ERR(child);
+}
+
+/* plugin->u.item.b.max_key_inside - not defined */
+
+/* plugin->u.item.b.nr_units - item.c:single_unit */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/internal.h linux-2.6.20/fs/reiser4/plugin/item/internal.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/internal.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/internal.h      2007-05-06 14:50:43.815011970 +0400
@@ -0,0 +1,57 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* Internal item contains down-link to the child of the internal/twig
+   node in a tree. It is internal items that are actually used during
+   tree traversal. */
+
+#if !defined( __FS_REISER4_PLUGIN_ITEM_INTERNAL_H__ )
+#define __FS_REISER4_PLUGIN_ITEM_INTERNAL_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+
+/* on-disk layout of internal item */
+typedef struct internal_item_layout {
+       /*  0 */ reiser4_dblock_nr pointer;
+       /*  4 */
+} internal_item_layout;
+
+struct cut_list;
+
+int mergeable_internal(const coord_t * p1, const coord_t * p2);
+lookup_result lookup_internal(const reiser4_key * key, lookup_bias bias,
+                             coord_t * coord);
+/* store pointer from internal item into "block". Implementation of
+    ->down_link() method */
+extern void down_link_internal(const coord_t * coord, const reiser4_key * key,
+                              reiser4_block_nr * block);
+extern int has_pointer_to_internal(const coord_t * coord,
+                                  const reiser4_block_nr * block);
+extern int create_hook_internal(const coord_t * item, void *arg);
+extern int kill_hook_internal(const coord_t * item, pos_in_node_t from,
+                             pos_in_node_t count, struct carry_kill_data *);
+extern int shift_hook_internal(const coord_t * item, unsigned from,
+                              unsigned count, znode * old_node);
+extern void reiser4_print_internal(const char *prefix, coord_t * coord);
+
+extern int utmost_child_internal(const coord_t * coord, sideof side,
+                                jnode ** child);
+int utmost_child_real_block_internal(const coord_t * coord, sideof side,
+                                    reiser4_block_nr * block);
+
+extern void reiser4_update_internal(const coord_t * coord,
+                                   const reiser4_block_nr * blocknr);
+/* FIXME: reiserfs has check_internal */
+extern int check__internal(const coord_t * coord, const char **error);
+
+/* __FS_REISER4_PLUGIN_ITEM_INTERNAL_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/item.c linux-2.6.20/fs/reiser4/plugin/item/item.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/item.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/item.c  2007-05-06 14:50:43.815011970 +0400
@@ -0,0 +1,719 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* definition of item plugins. */
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "../plugin_header.h"
+#include "sde.h"
+#include "internal.h"
+#include "item.h"
+#include "static_stat.h"
+#include "../plugin.h"
+#include "../../znode.h"
+#include "../../tree.h"
+#include "../../context.h"
+#include "ctail.h"
+
+/* return pointer to item body */
+void item_body_by_coord_hard(coord_t * coord /* coord to query */ )
+{
+       assert("nikita-324", coord != NULL);
+       assert("nikita-325", coord->node != NULL);
+       assert("nikita-326", znode_is_loaded(coord->node));
+       assert("nikita-3200", coord->offset == INVALID_OFFSET);
+
+       coord->offset =
+           node_plugin_by_node(coord->node)->item_by_coord(coord) -
+           zdata(coord->node);
+       ON_DEBUG(coord->body_v = coord->node->times_locked);
+}
+
+void *item_body_by_coord_easy(const coord_t * coord /* coord to query */ )
+{
+       return zdata(coord->node) + coord->offset;
+}
+
+#if REISER4_DEBUG
+
+int item_body_is_valid(const coord_t * coord)
+{
+       return
+           coord->offset ==
+           node_plugin_by_node(coord->node)->item_by_coord(coord) -
+           zdata(coord->node);
+}
+
+#endif
+
+/* return length of item at @coord */
+pos_in_node_t item_length_by_coord(const coord_t * coord /* coord to query */ )
+{
+       int len;
+
+       assert("nikita-327", coord != NULL);
+       assert("nikita-328", coord->node != NULL);
+       assert("nikita-329", znode_is_loaded(coord->node));
+
+       len = node_plugin_by_node(coord->node)->length_by_coord(coord);
+       return len;
+}
+
+void obtain_item_plugin(const coord_t * coord)
+{
+       assert("nikita-330", coord != NULL);
+       assert("nikita-331", coord->node != NULL);
+       assert("nikita-332", znode_is_loaded(coord->node));
+
+       coord_set_iplug((coord_t *) coord,
+                       node_plugin_by_node(coord->node)->
+                       plugin_by_coord(coord));
+       assert("nikita-2479",
+              coord_iplug(coord) ==
+              node_plugin_by_node(coord->node)->plugin_by_coord(coord));
+}
+
+/* return id of item */
+/* Audited by: green(2002.06.15) */
+item_id item_id_by_coord(const coord_t * coord /* coord to query */ )
+{
+       assert("vs-539", coord != NULL);
+       assert("vs-538", coord->node != NULL);
+       assert("vs-537", znode_is_loaded(coord->node));
+       assert("vs-536", item_plugin_by_coord(coord) != NULL);
+       assert("vs-540",
+              item_id_by_plugin(item_plugin_by_coord(coord)) < LAST_ITEM_ID);
+
+       return item_id_by_plugin(item_plugin_by_coord(coord));
+}
+
+/* return key of item at @coord */
+/* Audited by: green(2002.06.15) */
+reiser4_key *item_key_by_coord(const coord_t * coord /* coord to query */ ,
+                              reiser4_key * key /* result */ )
+{
+       assert("nikita-338", coord != NULL);
+       assert("nikita-339", coord->node != NULL);
+       assert("nikita-340", znode_is_loaded(coord->node));
+
+       return node_plugin_by_node(coord->node)->key_at(coord, key);
+}
+
+/* this returns max key in the item */
+reiser4_key *max_item_key_by_coord(const coord_t * coord /* coord to query */ ,
+                                  reiser4_key * key /* result */ )
+{
+       coord_t last;
+
+       assert("nikita-338", coord != NULL);
+       assert("nikita-339", coord->node != NULL);
+       assert("nikita-340", znode_is_loaded(coord->node));
+
+       /* make coord pointing to last item's unit */
+       coord_dup(&last, coord);
+       last.unit_pos = coord_num_units(&last) - 1;
+       assert("vs-1560", coord_is_existing_unit(&last));
+
+       max_unit_key_by_coord(&last, key);
+       return key;
+}
+
+/* return key of unit at @coord */
+reiser4_key *unit_key_by_coord(const coord_t * coord /* coord to query */ ,
+                              reiser4_key * key /* result */ )
+{
+       assert("nikita-772", coord != NULL);
+       assert("nikita-774", coord->node != NULL);
+       assert("nikita-775", znode_is_loaded(coord->node));
+
+       if (item_plugin_by_coord(coord)->b.unit_key != NULL)
+               return item_plugin_by_coord(coord)->b.unit_key(coord, key);
+       else
+               return item_key_by_coord(coord, key);
+}
+
+/* return the biggest key contained the unit @coord */
+reiser4_key *max_unit_key_by_coord(const coord_t * coord /* coord to query */ ,
+                                  reiser4_key * key /* result */ )
+{
+       assert("nikita-772", coord != NULL);
+       assert("nikita-774", coord->node != NULL);
+       assert("nikita-775", znode_is_loaded(coord->node));
+
+       if (item_plugin_by_coord(coord)->b.max_unit_key != NULL)
+               return item_plugin_by_coord(coord)->b.max_unit_key(coord, key);
+       else
+               return unit_key_by_coord(coord, key);
+}
+
+/* ->max_key_inside() method for items consisting of exactly one key (like
+    stat-data) */
+static reiser4_key *max_key_inside_single_key(const coord_t *
+                                             coord /* coord of item */ ,
+                                             reiser4_key *
+                                             result /* resulting key */ )
+{
+       assert("nikita-604", coord != NULL);
+
+       /* coord -> key is starting key of this item and it has to be already
+          filled in */
+       return unit_key_by_coord(coord, result);
+}
+
+/* ->nr_units() method for items consisting of exactly one unit always */
+pos_in_node_t
+nr_units_single_unit(const coord_t * coord UNUSED_ARG /* coord of item */ )
+{
+       return 1;
+}
+
+static int
+paste_no_paste(coord_t * coord UNUSED_ARG,
+              reiser4_item_data * data UNUSED_ARG,
+              carry_plugin_info * info UNUSED_ARG)
+{
+       return 0;
+}
+
+/* default ->fast_paste() method */
+static int
+agree_to_fast_op(const coord_t * coord UNUSED_ARG /* coord of item */ )
+{
+       return 1;
+}
+
+int item_can_contain_key(const coord_t * item /* coord of item */ ,
+                        const reiser4_key * key /* key to check */ ,
+                        const reiser4_item_data * data /* parameters of item
+                                                        * being created */ )
+{
+       item_plugin *iplug;
+       reiser4_key min_key_in_item;
+       reiser4_key max_key_in_item;
+
+       assert("nikita-1658", item != NULL);
+       assert("nikita-1659", key != NULL);
+
+       iplug = item_plugin_by_coord(item);
+       if (iplug->b.can_contain_key != NULL)
+               return iplug->b.can_contain_key(item, key, data);
+       else {
+               assert("nikita-1681", iplug->b.max_key_inside != NULL);
+               item_key_by_coord(item, &min_key_in_item);
+               iplug->b.max_key_inside(item, &max_key_in_item);
+
+               /* can contain key if
+                  min_key_in_item <= key &&
+                  key <= max_key_in_item
+                */
+               return keyle(&min_key_in_item, key)
+                   && keyle(key, &max_key_in_item);
+       }
+}
+
+/* mergeable method for non mergeable items */
+static int
+not_mergeable(const coord_t * i1 UNUSED_ARG, const coord_t * i2 UNUSED_ARG)
+{
+       return 0;
+}
+
+/* return 0 if @item1 and @item2 are not mergeable, !0 - otherwise */
+int are_items_mergeable(const coord_t * i1 /* coord of first item */ ,
+                       const coord_t * i2 /* coord of second item */ )
+{
+       item_plugin *iplug;
+       reiser4_key k1;
+       reiser4_key k2;
+
+       assert("nikita-1336", i1 != NULL);
+       assert("nikita-1337", i2 != NULL);
+
+       iplug = item_plugin_by_coord(i1);
+       assert("nikita-1338", iplug != NULL);
+
+       /* NOTE-NIKITA are_items_mergeable() is also called by assertions in
+          shifting code when nodes are in "suspended" state. */
+       assert("nikita-1663",
+              keyle(item_key_by_coord(i1, &k1), item_key_by_coord(i2, &k2)));
+
+       if (iplug->b.mergeable != NULL) {
+               return iplug->b.mergeable(i1, i2);
+       } else if (iplug->b.max_key_inside != NULL) {
+               iplug->b.max_key_inside(i1, &k1);
+               item_key_by_coord(i2, &k2);
+
+               /* mergeable if ->max_key_inside() >= key of i2; */
+               return keyge(iplug->b.max_key_inside(i1, &k1),
+                            item_key_by_coord(i2, &k2));
+       } else {
+               item_key_by_coord(i1, &k1);
+               item_key_by_coord(i2, &k2);
+
+               return
+                   (get_key_locality(&k1) == get_key_locality(&k2)) &&
+                   (get_key_objectid(&k1) == get_key_objectid(&k2))
+                   && (iplug == item_plugin_by_coord(i2));
+       }
+}
+
+int item_is_extent(const coord_t * item)
+{
+       assert("vs-482", coord_is_existing_item(item));
+       return item_id_by_coord(item) == EXTENT_POINTER_ID;
+}
+
+int item_is_tail(const coord_t * item)
+{
+       assert("vs-482", coord_is_existing_item(item));
+       return item_id_by_coord(item) == FORMATTING_ID;
+}
+
+#if REISER4_DEBUG
+
+int item_is_statdata(const coord_t * item)
+{
+       assert("vs-516", coord_is_existing_item(item));
+       return plugin_of_group(item_plugin_by_coord(item), STAT_DATA_ITEM_TYPE);
+}
+
+int item_is_ctail(const coord_t * item)
+{
+       assert("edward-xx", coord_is_existing_item(item));
+       return item_id_by_coord(item) == CTAIL_ID;
+}
+
+#endif  /*  REISER4_DEBUG  */
+
+static int change_item(struct inode *inode,
+                      reiser4_plugin * plugin,
+                      pset_member memb)
+{
+       /* cannot change constituent item (sd, or dir_item) */
+       return RETERR(-EINVAL);
+}
+
+static reiser4_plugin_ops item_plugin_ops = {
+       .init = NULL,
+       .load = NULL,
+       .save_len = NULL,
+       .save = NULL,
+       .change = change_item
+};
+
+item_plugin item_plugins[LAST_ITEM_ID] = {
+       [STATIC_STAT_DATA_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = STATIC_STAT_DATA_ID,
+                       .groups = (1 << STAT_DATA_ITEM_TYPE),
+                       .pops = &item_plugin_ops,
+                       .label = "sd",
+                       .desc = "stat-data",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_single_key,
+                       .can_contain_key = NULL,
+                       .mergeable = not_mergeable,
+                       .nr_units = nr_units_single_unit,
+                       .lookup = NULL,
+                       .init = NULL,
+                       .paste = paste_no_paste,
+                       .fast_paste = NULL,
+                       .can_shift = NULL,
+                       .copy_units = NULL,
+                       .create_hook = NULL,
+                       .kill_hook = NULL,
+                       .shift_hook = NULL,
+                       .cut_units = NULL,
+                       .kill_units = NULL,
+                       .unit_key = NULL,
+                       .max_unit_key = NULL,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = NULL
+#endif
+               },
+               .f = {
+                       .utmost_child = NULL,
+                       .utmost_child_real_block = NULL,
+                       .update = NULL,
+                       .scan = NULL,
+                       .convert = NULL
+               },
+               .s = {
+                       .sd = {
+                               .init_inode = init_inode_static_sd,
+                               .save_len = save_len_static_sd,
+                               .save = save_static_sd
+                       }
+               }
+       },
+       [SIMPLE_DIR_ENTRY_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = SIMPLE_DIR_ENTRY_ID,
+                       .groups = (1 << DIR_ENTRY_ITEM_TYPE),
+                       .pops = &item_plugin_ops,
+                       .label = "de",
+                       .desc = "directory entry",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_single_key,
+                       .can_contain_key = NULL,
+                       .mergeable = NULL,
+                       .nr_units = nr_units_single_unit,
+                       .lookup = NULL,
+                       .init = NULL,
+                       .paste = NULL,
+                       .fast_paste = NULL,
+                       .can_shift = NULL,
+                       .copy_units = NULL,
+                       .create_hook = NULL,
+                       .kill_hook = NULL,
+                       .shift_hook = NULL,
+                       .cut_units = NULL,
+                       .kill_units = NULL,
+                       .unit_key = NULL,
+                       .max_unit_key = NULL,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = NULL
+#endif
+               },
+               .f = {
+                       .utmost_child = NULL,
+                       .utmost_child_real_block = NULL,
+                       .update = NULL,
+                       .scan = NULL,
+                       .convert = NULL
+               },
+               .s = {
+                       .dir = {
+                               .extract_key = extract_key_de,
+                               .update_key = update_key_de,
+                               .extract_name = extract_name_de,
+                               .extract_file_type = extract_file_type_de,
+                               .add_entry = add_entry_de,
+                               .rem_entry = rem_entry_de,
+                               .max_name_len = max_name_len_de
+                       }
+               }
+       },
+       [COMPOUND_DIR_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = COMPOUND_DIR_ID,
+                       .groups = (1 << DIR_ENTRY_ITEM_TYPE),
+                       .pops = &item_plugin_ops,
+                       .label = "cde",
+                       .desc = "compressed directory entry",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_cde,
+                       .can_contain_key = can_contain_key_cde,
+                       .mergeable = mergeable_cde,
+                       .nr_units = nr_units_cde,
+                       .lookup = lookup_cde,
+                       .init = init_cde,
+                       .paste = paste_cde,
+                       .fast_paste = agree_to_fast_op,
+                       .can_shift = can_shift_cde,
+                       .copy_units = copy_units_cde,
+                       .create_hook = NULL,
+                       .kill_hook = NULL,
+                       .shift_hook = NULL,
+                       .cut_units = cut_units_cde,
+                       .kill_units = kill_units_cde,
+                       .unit_key = unit_key_cde,
+                       .max_unit_key = unit_key_cde,
+                       .estimate = estimate_cde,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = reiser4_check_cde
+#endif
+               },
+               .f = {
+                       .utmost_child = NULL,
+                       .utmost_child_real_block = NULL,
+                       .update = NULL,
+                       .scan = NULL,
+                       .convert = NULL
+               },
+               .s = {
+                       .dir = {
+                               .extract_key = extract_key_cde,
+                               .update_key = update_key_cde,
+                               .extract_name = extract_name_cde,
+                               .extract_file_type = extract_file_type_de,
+                               .add_entry = add_entry_cde,
+                               .rem_entry = rem_entry_cde,
+                               .max_name_len = max_name_len_cde
+                       }
+               }
+       },
+       [NODE_POINTER_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = NODE_POINTER_ID,
+                       .groups = (1 << INTERNAL_ITEM_TYPE),
+                       .pops = NULL,
+                       .label = "internal",
+                       .desc = "internal item",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = NULL,
+                       .can_contain_key = NULL,
+                       .mergeable = mergeable_internal,
+                       .nr_units = nr_units_single_unit,
+                       .lookup = lookup_internal,
+                       .init = NULL,
+                       .paste = NULL,
+                       .fast_paste = NULL,
+                       .can_shift = NULL,
+                       .copy_units = NULL,
+                       .create_hook = create_hook_internal,
+                       .kill_hook = kill_hook_internal,
+                       .shift_hook = shift_hook_internal,
+                       .cut_units = NULL,
+                       .kill_units = NULL,
+                       .unit_key = NULL,
+                       .max_unit_key = NULL,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = check__internal
+#endif
+               },
+               .f = {
+                       .utmost_child = utmost_child_internal,
+                       .utmost_child_real_block =
+                       utmost_child_real_block_internal,
+                       .update = reiser4_update_internal,
+                       .scan = NULL,
+                       .convert = NULL
+               },
+               .s = {
+                       .internal = {
+                               .down_link = down_link_internal,
+                               .has_pointer_to = has_pointer_to_internal
+                       }
+               }
+       },
+       [EXTENT_POINTER_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = EXTENT_POINTER_ID,
+                       .groups = (1 << UNIX_FILE_METADATA_ITEM_TYPE),
+                       .pops = NULL,
+                       .label = "extent",
+                       .desc = "extent item",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_extent,
+                       .can_contain_key = can_contain_key_extent,
+                       .mergeable = mergeable_extent,
+                       .nr_units = nr_units_extent,
+                       .lookup = lookup_extent,
+                       .init = NULL,
+                       .paste = paste_extent,
+                       .fast_paste = agree_to_fast_op,
+                       .can_shift = can_shift_extent,
+                       .create_hook = create_hook_extent,
+                       .copy_units = copy_units_extent,
+                       .kill_hook = kill_hook_extent,
+                       .shift_hook = NULL,
+                       .cut_units = cut_units_extent,
+                       .kill_units = kill_units_extent,
+                       .unit_key = unit_key_extent,
+                       .max_unit_key = max_unit_key_extent,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = reiser4_check_extent
+#endif
+               },
+               .f = {
+                       .utmost_child = utmost_child_extent,
+                       .utmost_child_real_block =
+                       utmost_child_real_block_extent,
+                       .update = NULL,
+                       .scan = reiser4_scan_extent,
+                       .convert = NULL,
+                       .key_by_offset = key_by_offset_extent
+               },
+               .s = {
+                       .file = {
+                               .write = reiser4_write_extent,
+                               .read = reiser4_read_extent,
+                               .readpage = reiser4_readpage_extent,
+                               .get_block = get_block_address_extent,
+                               .append_key = append_key_extent,
+                               .init_coord_extension =
+                               init_coord_extension_extent
+                       }
+               }
+       },
+       [FORMATTING_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = FORMATTING_ID,
+                       .groups = (1 << UNIX_FILE_METADATA_ITEM_TYPE),
+                       .pops = NULL,
+                       .label = "body",
+                       .desc = "body (or tail?) item",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_tail,
+                       .can_contain_key = can_contain_key_tail,
+                       .mergeable = mergeable_tail,
+                       .nr_units = nr_units_tail,
+                       .lookup = lookup_tail,
+                       .init = NULL,
+                       .paste = paste_tail,
+                       .fast_paste = agree_to_fast_op,
+                       .can_shift = can_shift_tail,
+                       .create_hook = NULL,
+                       .copy_units = copy_units_tail,
+                       .kill_hook = kill_hook_tail,
+                       .shift_hook = NULL,
+                       .cut_units = cut_units_tail,
+                       .kill_units = kill_units_tail,
+                       .unit_key = unit_key_tail,
+                       .max_unit_key = unit_key_tail,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = NULL
+#endif
+               },
+               .f = {
+                       .utmost_child = NULL,
+                       .utmost_child_real_block = NULL,
+                       .update = NULL,
+                       .scan = NULL,
+                       .convert = NULL
+               },
+               .s = {
+                       .file = {
+                               .write = reiser4_write_tail,
+                               .read = reiser4_read_tail,
+                               .readpage = readpage_tail,
+                               .get_block = get_block_address_tail,
+                               .append_key = append_key_tail,
+                               .init_coord_extension =
+                               init_coord_extension_tail
+                       }
+               }
+       },
+       [CTAIL_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = CTAIL_ID,
+                       .groups = (1 << UNIX_FILE_METADATA_ITEM_TYPE),
+                       .pops = NULL,
+                       .label = "ctail",
+                       .desc = "cryptcompress tail item",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = max_key_inside_tail,
+                       .can_contain_key = can_contain_key_ctail,
+                       .mergeable = mergeable_ctail,
+                       .nr_units = nr_units_ctail,
+                       .lookup = NULL,
+                       .init = init_ctail,
+                       .paste = paste_ctail,
+                       .fast_paste = agree_to_fast_op,
+                       .can_shift = can_shift_ctail,
+                       .create_hook = create_hook_ctail,
+                       .copy_units = copy_units_ctail,
+                       .kill_hook = kill_hook_ctail,
+                       .shift_hook = shift_hook_ctail,
+                       .cut_units = cut_units_ctail,
+                       .kill_units = kill_units_ctail,
+                       .unit_key = unit_key_tail,
+                       .max_unit_key = unit_key_tail,
+                       .estimate = estimate_ctail,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = check_ctail
+#endif
+               },
+               .f = {
+                       .utmost_child = utmost_child_ctail,
+                       /* FIXME-EDWARD: write this */
+                       .utmost_child_real_block = NULL,
+                       .update = NULL,
+                       .scan = scan_ctail,
+                       .convert = convert_ctail
+               },
+               .s = {
+                       .file = {
+                               .write = NULL,
+                               .read = read_ctail,
+                               .readpage = readpage_ctail,
+                               .get_block = get_block_address_tail,
+                               .append_key = append_key_ctail,
+                               .init_coord_extension =
+                               init_coord_extension_tail
+                       }
+               }
+       },
+       [BLACK_BOX_ID] = {
+               .h = {
+                       .type_id = REISER4_ITEM_PLUGIN_TYPE,
+                       .id = BLACK_BOX_ID,
+                       .groups = (1 << OTHER_ITEM_TYPE),
+                       .pops = NULL,
+                       .label = "blackbox",
+                       .desc = "black box item",
+                       .linkage = {NULL, NULL}
+               },
+               .b = {
+                       .max_key_inside = NULL,
+                       .can_contain_key = NULL,
+                       .mergeable = not_mergeable,
+                       .nr_units = nr_units_single_unit,
+                       /* to need for ->lookup method */
+                       .lookup = NULL,
+                       .init = NULL,
+                       .paste = NULL,
+                       .fast_paste = NULL,
+                       .can_shift = NULL,
+                       .copy_units = NULL,
+                       .create_hook = NULL,
+                       .kill_hook = NULL,
+                       .shift_hook = NULL,
+                       .cut_units = NULL,
+                       .kill_units = NULL,
+                       .unit_key = NULL,
+                       .max_unit_key = NULL,
+                       .estimate = NULL,
+                       .item_data_by_flow = NULL,
+#if REISER4_DEBUG
+                       .check = NULL
+#endif
+               }
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/item.h linux-2.6.20/fs/reiser4/plugin/item/item.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/item.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/item.h  2007-05-06 14:50:43.819013220 +0400
@@ -0,0 +1,400 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* first read balance.c comments before reading this */
+
+/* An item_plugin implements all of the operations required for
+   balancing that are item specific. */
+
+/* an item plugin also implements other operations that are specific to that
+   item.  These go into the item specific operations portion of the item
+   handler, and all of the item specific portions of the item handler are put
+   into a union. */
+
+#if !defined( __REISER4_ITEM_H__ )
+#define __REISER4_ITEM_H__
+
+#include "../../forward.h"
+#include "../plugin_header.h"
+#include "../../dformat.h"
+#include "../../seal.h"
+#include "../../plugin/file/file.h"
+
+#include <linux/fs.h>          /* for struct file, struct inode  */
+#include <linux/mm.h>          /* for struct page */
+#include <linux/dcache.h>      /* for struct dentry */
+
+typedef enum {
+       STAT_DATA_ITEM_TYPE,
+       DIR_ENTRY_ITEM_TYPE,
+       INTERNAL_ITEM_TYPE,
+       UNIX_FILE_METADATA_ITEM_TYPE,
+       OTHER_ITEM_TYPE
+} item_type_id;
+
+/* this is the part of each item plugin that all items are expected to
+   support or at least explicitly fail to support by setting the
+   pointer to null. */
+typedef struct {
+       /* operations called by balancing
+
+          It is interesting to consider that some of these item
+          operations could be given sources or targets that are not
+          really items in nodes.  This could be ok/useful.
+
+        */
+       /* maximal key that can _possibly_ be occupied by this item
+
+          When inserting, and node ->lookup() method (called by
+          coord_by_key()) reaches an item after binary search,
+          the  ->max_key_inside() item plugin method is used to determine
+          whether new item should pasted into existing item
+          (new_key<=max_key_inside()) or new item has to be created
+          (new_key>max_key_inside()).
+
+          For items that occupy exactly one key (like stat-data)
+          this method should return this key. For items that can
+          grow indefinitely (extent, directory item) this should
+          return reiser4_max_key().
+
+          For example extent with the key
+
+          (LOCALITY,4,OBJID,STARTING-OFFSET), and length BLK blocks,
+
+          ->max_key_inside is (LOCALITY,4,OBJID,0xffffffffffffffff), and
+        */
+       reiser4_key *(*max_key_inside) (const coord_t *, reiser4_key *);
+
+       /* true if item @coord can merge data at @key. */
+       int (*can_contain_key) (const coord_t *, const reiser4_key *,
+                               const reiser4_item_data *);
+       /* mergeable() - check items for mergeability
+
+          Optional method. Returns true if two items can be merged.
+
+        */
+       int (*mergeable) (const coord_t *, const coord_t *);
+
+       /* number of atomic things in an item.
+          NOTE FOR CONTRIBUTORS: use a generic method
+          nr_units_single_unit() for solid (atomic) items, as
+          tree operations use it as a criterion of solidness
+          (see is_solid_item macro) */
+       pos_in_node_t(*nr_units) (const coord_t *);
+
+       /* search within item for a unit within the item, and return a
+          pointer to it.  This can be used to calculate how many
+          bytes to shrink an item if you use pointer arithmetic and
+          compare to the start of the item body if the item's data
+          are continuous in the node, if the item's data are not
+          continuous in the node, all sorts of other things are maybe
+          going to break as well. */
+        lookup_result(*lookup) (const reiser4_key *, lookup_bias, coord_t *);
+       /* method called by ode_plugin->create_item() to initialise new
+          item */
+       int (*init) (coord_t * target, coord_t * from,
+                    reiser4_item_data * data);
+       /* method called (e.g., by reiser4_resize_item()) to place new data
+          into item when it grows */
+       int (*paste) (coord_t *, reiser4_item_data *, carry_plugin_info *);
+       /* return true if paste into @coord is allowed to skip
+          carry. That is, if such paste would require any changes
+          at the parent level
+        */
+       int (*fast_paste) (const coord_t *);
+       /* how many but not more than @want units of @source can be
+          shifted into @target node. If pend == append - we try to
+          append last item of @target by first units of @source. If
+          pend == prepend - we try to "prepend" first item in @target
+          by last units of @source. @target node has @free_space
+          bytes of free space. Total size of those units are returned
+          via @size.
+
+          @target is not NULL if shifting to the mergeable item and
+          NULL is new item will be created during shifting.
+        */
+       int (*can_shift) (unsigned free_space, coord_t *,
+                         znode *, shift_direction, unsigned *size,
+                         unsigned want);
+
+       /* starting off @from-th unit of item @source append or
+          prepend @count units to @target. @target has been already
+          expanded by @free_space bytes. That must be exactly what is
+          needed for those items in @target. If @where_is_free_space
+          == SHIFT_LEFT - free space is at the end of @target item,
+          othersize - it is in the beginning of it. */
+       void (*copy_units) (coord_t *, coord_t *,
+                           unsigned from, unsigned count,
+                           shift_direction where_is_free_space,
+                           unsigned free_space);
+
+       int (*create_hook) (const coord_t *, void *);
+       /* do whatever is necessary to do when @count units starting
+          from @from-th one are removed from the tree */
+       /* FIXME-VS: this is used to be here for, in particular,
+          extents and items of internal type to free blocks they point
+          to at the same time with removing items from a
+          tree. Problems start, however, when dealloc_block fails due
+          to some reason. Item gets removed, but blocks it pointed to
+          are not freed. It is not clear how to fix this for items of
+          internal type because a need to remove internal item may
+          appear in the middle of balancing, and there is no way to
+          undo changes made. OTOH, if space allocator involves
+          balancing to perform dealloc_block - this will probably
+          break balancing due to deadlock issues
+        */
+       int (*kill_hook) (const coord_t *, pos_in_node_t from,
+                         pos_in_node_t count, struct carry_kill_data *);
+       int (*shift_hook) (const coord_t *, unsigned from, unsigned count,
+                          znode * _node);
+
+       /* unit @*from contains @from_key. unit @*to contains @to_key. Cut all keys between @from_key and @to_key
+          including boundaries. When units are cut from item beginning - move space which gets freed to head of
+          item. When units are cut from item end - move freed space to item end. When units are cut from the middle of
+          item - move freed space to item head. Return amount of space which got freed. Save smallest removed key in
+          @smallest_removed if it is not 0. Save new first item key in @new_first_key if it is not 0
+        */
+       int (*cut_units) (coord_t *, pos_in_node_t from, pos_in_node_t to,
+                         struct carry_cut_data *,
+                         reiser4_key * smallest_removed,
+                         reiser4_key * new_first_key);
+
+       /* like cut_units, except that these units are removed from the
+          tree, not only from a node */
+       int (*kill_units) (coord_t *, pos_in_node_t from, pos_in_node_t to,
+                          struct carry_kill_data *,
+                          reiser4_key * smallest_removed,
+                          reiser4_key * new_first);
+
+       /* if @key_of_coord == 1 - returned key of coord, otherwise -
+          key of unit is returned. If @coord is not set to certain
+          unit - ERR_PTR(-ENOENT) is returned */
+       reiser4_key *(*unit_key) (const coord_t *, reiser4_key *);
+       reiser4_key *(*max_unit_key) (const coord_t *, reiser4_key *);
+       /* estimate how much space is needed for paste @data into item at
+          @coord. if @coord==0 - estimate insertion, otherwise - estimate
+          pasting
+        */
+       int (*estimate) (const coord_t *, const reiser4_item_data *);
+
+       /* converts flow @f to item data. @coord == 0 on insert */
+       int (*item_data_by_flow) (const coord_t *, const flow_t *,
+                                 reiser4_item_data *);
+
+       /*void (*show) (struct seq_file *, coord_t *); */
+
+#if REISER4_DEBUG
+       /* used for debugging, every item should have here the most
+          complete possible check of the consistency of the item that
+          the inventor can construct */
+       int (*check) (const coord_t *, const char **error);
+#endif
+
+} balance_ops;
+
+typedef struct {
+       /* return the right or left child of @coord, only if it is in memory */
+       int (*utmost_child) (const coord_t *, sideof side, jnode ** child);
+
+       /* return whether the right or left child of @coord has a non-fake
+          block number. */
+       int (*utmost_child_real_block) (const coord_t *, sideof side,
+                                       reiser4_block_nr *);
+       /* relocate child at @coord to the @block */
+       void (*update) (const coord_t *, const reiser4_block_nr *);
+       /* count unformatted nodes per item for leave relocation policy, etc.. */
+       int (*scan) (flush_scan * scan);
+       /* convert item by flush */
+       int (*convert) (flush_pos_t * pos);
+       /* backward mapping from jnode offset to a key.  */
+       int (*key_by_offset) (struct inode *, loff_t, reiser4_key *);
+} flush_ops;
+
+/* operations specific to the directory item */
+typedef struct {
+       /* extract stat-data key from directory entry at @coord and place it
+          into @key. */
+       int (*extract_key) (const coord_t *, reiser4_key * key);
+       /* update object key in item. */
+       int (*update_key) (const coord_t *, const reiser4_key *, lock_handle *);
+       /* extract name from directory entry at @coord and return it */
+       char *(*extract_name) (const coord_t *, char *buf);
+       /* extract file type (DT_* stuff) from directory entry at @coord and
+          return it */
+       unsigned (*extract_file_type) (const coord_t *);
+       int (*add_entry) (struct inode * dir,
+                         coord_t *, lock_handle *,
+                         const struct dentry * name,
+                         reiser4_dir_entry_desc * entry);
+       int (*rem_entry) (struct inode * dir, const struct qstr * name,
+                         coord_t *, lock_handle *,
+                         reiser4_dir_entry_desc * entry);
+       int (*max_name_len) (const struct inode * dir);
+} dir_entry_ops;
+
+/* operations specific to items regular (unix) file metadata are built of */
+typedef struct {
+       int (*write) (struct file *, const char __user *, size_t, loff_t *pos);
+       int (*read) (struct file *, flow_t *, hint_t *);
+       int (*readpage) (void *, struct page *);
+       int (*get_block) (const coord_t *, sector_t, sector_t *);
+       /*
+        * key of first byte which is not addressed by the item @coord is set
+        * to.
+        * For example, for extent item with the key
+        *
+        * (LOCALITY,4,OBJID,STARTING-OFFSET), and length BLK blocks,
+        *
+        * ->append_key is
+        *
+        * (LOCALITY,4,OBJID,STARTING-OFFSET + BLK * block_size)
+        */
+       reiser4_key *(*append_key) (const coord_t *, reiser4_key *);
+
+       void (*init_coord_extension) (uf_coord_t *, loff_t);
+} file_ops;
+
+/* operations specific to items of stat data type */
+typedef struct {
+       int (*init_inode) (struct inode * inode, char *sd, int len);
+       int (*save_len) (struct inode * inode);
+       int (*save) (struct inode * inode, char **area);
+} sd_ops;
+
+/* operations specific to internal item */
+typedef struct {
+       /* all tree traversal want to know from internal item is where
+          to go next. */
+       void (*down_link) (const coord_t * coord,
+                          const reiser4_key * key, reiser4_block_nr * block);
+       /* check that given internal item contains given pointer. */
+       int (*has_pointer_to) (const coord_t * coord,
+                              const reiser4_block_nr * block);
+} internal_item_ops;
+
+struct item_plugin {
+       /* generic fields */
+       plugin_header h;
+
+       /* methods common for all item types */
+       balance_ops b;
+       /* methods used during flush */
+       flush_ops f;
+
+       /* methods specific to particular type of item */
+       union {
+               dir_entry_ops dir;
+               file_ops file;
+               sd_ops sd;
+               internal_item_ops internal;
+       } s;
+
+};
+
+#define is_solid_item(iplug) ((iplug)->b.nr_units == nr_units_single_unit)
+
+static inline item_id item_id_by_plugin(item_plugin * plugin)
+{
+       return plugin->h.id;
+}
+
+static inline char get_iplugid(item_plugin * iplug)
+{
+       assert("nikita-2838", iplug != NULL);
+       assert("nikita-2839", iplug->h.id < 0xff);
+       return (char)item_id_by_plugin(iplug);
+}
+
+extern unsigned long znode_times_locked(const znode * z);
+
+static inline void coord_set_iplug(coord_t * coord, item_plugin * iplug)
+{
+       assert("nikita-2837", coord != NULL);
+       assert("nikita-2838", iplug != NULL);
+       coord->iplugid = get_iplugid(iplug);
+       ON_DEBUG(coord->plug_v = znode_times_locked(coord->node));
+}
+
+static inline item_plugin *coord_iplug(const coord_t * coord)
+{
+       assert("nikita-2833", coord != NULL);
+       assert("nikita-2834", coord->iplugid != INVALID_PLUGID);
+       assert("nikita-3549", coord->plug_v == znode_times_locked(coord->node));
+       return (item_plugin *) plugin_by_id(REISER4_ITEM_PLUGIN_TYPE,
+                                           coord->iplugid);
+}
+
+extern int item_can_contain_key(const coord_t * item, const reiser4_key * key,
+                               const reiser4_item_data *);
+extern int are_items_mergeable(const coord_t * i1, const coord_t * i2);
+extern int item_is_extent(const coord_t *);
+extern int item_is_tail(const coord_t *);
+extern int item_is_statdata(const coord_t * item);
+extern int item_is_ctail(const coord_t *);
+
+extern pos_in_node_t item_length_by_coord(const coord_t * coord);
+extern pos_in_node_t nr_units_single_unit(const coord_t * coord);
+extern item_id item_id_by_coord(const coord_t * coord /* coord to query */ );
+extern reiser4_key *item_key_by_coord(const coord_t * coord, reiser4_key * key);
+extern reiser4_key *max_item_key_by_coord(const coord_t *, reiser4_key *);
+extern reiser4_key *unit_key_by_coord(const coord_t * coord, reiser4_key * key);
+extern reiser4_key *max_unit_key_by_coord(const coord_t * coord,
+                                         reiser4_key * key);
+extern void obtain_item_plugin(const coord_t * coord);
+
+#if defined(REISER4_DEBUG)
+extern int znode_is_loaded(const znode * node);
+#endif
+
+/* return plugin of item at @coord */
+static inline item_plugin *item_plugin_by_coord(const coord_t *
+                                               coord /* coord to query */ )
+{
+       assert("nikita-330", coord != NULL);
+       assert("nikita-331", coord->node != NULL);
+       assert("nikita-332", znode_is_loaded(coord->node));
+
+       if (unlikely(!coord_is_iplug_set(coord)))
+               obtain_item_plugin(coord);
+       return coord_iplug(coord);
+}
+
+/* this returns true if item is of internal type */
+static inline int item_is_internal(const coord_t * item)
+{
+       assert("vs-483", coord_is_existing_item(item));
+       return plugin_of_group(item_plugin_by_coord(item), INTERNAL_ITEM_TYPE);
+}
+
+extern void item_body_by_coord_hard(coord_t * coord);
+extern void *item_body_by_coord_easy(const coord_t * coord);
+#if REISER4_DEBUG
+extern int item_body_is_valid(const coord_t * coord);
+#endif
+
+/* return pointer to item body */
+static inline void *item_body_by_coord(const coord_t *
+                                      coord /* coord to query */ )
+{
+       assert("nikita-324", coord != NULL);
+       assert("nikita-325", coord->node != NULL);
+       assert("nikita-326", znode_is_loaded(coord->node));
+
+       if (coord->offset == INVALID_OFFSET)
+               item_body_by_coord_hard((coord_t *) coord);
+       assert("nikita-3201", item_body_is_valid(coord));
+       assert("nikita-3550", coord->body_v == znode_times_locked(coord->node));
+       return item_body_by_coord_easy(coord);
+}
+
+/* __REISER4_ITEM_H__ */
+#endif
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/Makefile linux-2.6.20/fs/reiser4/plugin/item/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/item/Makefile   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/Makefile        2007-05-06 14:50:43.819013220 +0400
@@ -0,0 +1,18 @@
+obj-$(CONFIG_REISER4_FS) += item_plugins.o
+
+item_plugins-objs :=           \
+       item.o                  \
+       static_stat.o           \
+       sde.o                   \
+       cde.o                   \
+       blackbox.o              \
+       internal.o              \
+       tail.o                  \
+       ctail.o                 \
+       extent.o                \
+       extent_item_ops.o       \
+       extent_file_ops.o       \
+       extent_flush_ops.o
+
+
+
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/sde.c linux-2.6.20/fs/reiser4/plugin/item/sde.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/sde.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/sde.c   2007-05-06 14:50:43.819013220 +0400
@@ -0,0 +1,190 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Directory entry implementation */
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../coord.h"
+#include "sde.h"
+#include "item.h"
+#include "../plugin.h"
+#include "../../znode.h"
+#include "../../carry.h"
+#include "../../tree.h"
+#include "../../inode.h"
+
+#include <linux/fs.h>          /* for struct inode */
+#include <linux/dcache.h>      /* for struct dentry */
+#include <linux/quotaops.h>
+
+/* ->extract_key() method of simple directory item plugin. */
+int extract_key_de(const coord_t * coord /* coord of item */ ,
+                  reiser4_key * key /* resulting key */ )
+{
+       directory_entry_format *dent;
+
+       assert("nikita-1458", coord != NULL);
+       assert("nikita-1459", key != NULL);
+
+       dent = (directory_entry_format *) item_body_by_coord(coord);
+       assert("nikita-1158", item_length_by_coord(coord) >= (int)sizeof *dent);
+       return extract_key_from_id(&dent->id, key);
+}
+
+int
+update_key_de(const coord_t * coord, const reiser4_key * key,
+             lock_handle * lh UNUSED_ARG)
+{
+       directory_entry_format *dent;
+       obj_key_id obj_id;
+       int result;
+
+       assert("nikita-2342", coord != NULL);
+       assert("nikita-2343", key != NULL);
+
+       dent = (directory_entry_format *) item_body_by_coord(coord);
+       result = build_obj_key_id(key, &obj_id);
+       if (result == 0) {
+               dent->id = obj_id;
+               znode_make_dirty(coord->node);
+       }
+       return 0;
+}
+
+char *extract_dent_name(const coord_t * coord, directory_entry_format * dent,
+                       char *buf)
+{
+       reiser4_key key;
+
+       unit_key_by_coord(coord, &key);
+       if (get_key_type(&key) != KEY_FILE_NAME_MINOR)
+               reiser4_print_address("oops", znode_get_block(coord->node));
+       if (!is_longname_key(&key)) {
+               if (is_dot_key(&key))
+                       return (char *)".";
+               else
+                       return extract_name_from_key(&key, buf);
+       } else
+               return (char *)dent->name;
+}
+
+/* ->extract_name() method of simple directory item plugin. */
+char *extract_name_de(const coord_t * coord /* coord of item */ , char *buf)
+{
+       directory_entry_format *dent;
+
+       assert("nikita-1460", coord != NULL);
+
+       dent = (directory_entry_format *) item_body_by_coord(coord);
+       return extract_dent_name(coord, dent, buf);
+}
+
+/* ->extract_file_type() method of simple directory item plugin. */
+unsigned extract_file_type_de(const coord_t * coord UNUSED_ARG /* coord of
+                                                                * item */ )
+{
+       assert("nikita-1764", coord != NULL);
+       /* we don't store file type in the directory entry yet.
+
+          But see comments at kassign.h:obj_key_id
+        */
+       return DT_UNKNOWN;
+}
+
+int add_entry_de(struct inode *dir /* directory of item */ ,
+                coord_t * coord /* coord of item */ ,
+                lock_handle * lh /* insertion lock handle */ ,
+                const struct dentry *de /* name to add */ ,
+                reiser4_dir_entry_desc * entry /* parameters of new directory
+                                                * entry */ )
+{
+       reiser4_item_data data;
+       directory_entry_format *dent;
+       int result;
+       const char *name;
+       int len;
+       int longname;
+
+       name = de->d_name.name;
+       len = de->d_name.len;
+       assert("nikita-1163", strlen(name) == len);
+
+       longname = is_longname(name, len);
+
+       data.length = sizeof *dent;
+       if (longname)
+               data.length += len + 1;
+       data.data = NULL;
+       data.user = 0;
+       data.iplug = item_plugin_by_id(SIMPLE_DIR_ENTRY_ID);
+
+       /* NOTE-NIKITA quota plugin */
+       if (DQUOT_ALLOC_SPACE_NODIRTY(dir, data.length))
+               return -EDQUOT;
+
+       result = insert_by_coord(coord, &data, &entry->key, lh, 0 /*flags */ );
+       if (result != 0)
+               return result;
+
+       dent = (directory_entry_format *) item_body_by_coord(coord);
+       build_inode_key_id(entry->obj, &dent->id);
+       if (longname) {
+               memcpy(dent->name, name, len);
+               put_unaligned(0, &dent->name[len]);
+       }
+       return 0;
+}
+
+int rem_entry_de(struct inode *dir /* directory of item */ ,
+                const struct qstr *name UNUSED_ARG,
+                coord_t * coord /* coord of item */ ,
+                lock_handle * lh UNUSED_ARG    /* lock handle for
+                                                * removal */ ,
+                reiser4_dir_entry_desc * entry UNUSED_ARG      /* parameters of
+                                                                * directory entry
+                                                                * being removed */ )
+{
+       coord_t shadow;
+       int result;
+       int length;
+
+       length = item_length_by_coord(coord);
+       if (inode_get_bytes(dir) < length) {
+               warning("nikita-2627", "Dir is broke: %llu: %llu",
+                       (unsigned long long)get_inode_oid(dir),
+                       inode_get_bytes(dir));
+
+               return RETERR(-EIO);
+       }
+
+       /* cut_node() is supposed to take pointers to _different_
+          coords, because it will modify them without respect to
+          possible aliasing. To work around this, create temporary copy
+          of @coord.
+        */
+       coord_dup(&shadow, coord);
+       result =
+           kill_node_content(coord, &shadow, NULL, NULL, NULL, NULL, NULL, 0);
+       if (result == 0) {
+               /* NOTE-NIKITA quota plugin */
+               DQUOT_FREE_SPACE_NODIRTY(dir, length);
+       }
+       return result;
+}
+
+int max_name_len_de(const struct inode *dir)
+{
+       return reiser4_tree_by_inode(dir)->nplug->max_item_size() -
+               sizeof(directory_entry_format) - 2;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/sde.h linux-2.6.20/fs/reiser4/plugin/item/sde.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/sde.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/sde.h   2007-05-06 14:50:43.819013220 +0400
@@ -0,0 +1,66 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Directory entry. */
+
+#if !defined( __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__ )
+#define __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+#include "../../kassign.h"
+#include "../../key.h"
+
+#include <linux/fs.h>
+#include <linux/dcache.h>      /* for struct dentry */
+
+typedef struct directory_entry_format {
+       /* key of object stat-data. It's not necessary to store whole
+          key here, because it's always key of stat-data, so minor
+          packing locality and offset can be omitted here. But this
+          relies on particular key allocation scheme for stat-data, so,
+          for extensibility sake, whole key can be stored here.
+
+          We store key as array of bytes, because we don't want 8-byte
+          alignment of dir entries.
+        */
+       obj_key_id id;
+       /* file name. Null terminated string. */
+       d8 name[0];
+} directory_entry_format;
+
+void print_de(const char *prefix, coord_t * coord);
+int extract_key_de(const coord_t * coord, reiser4_key * key);
+int update_key_de(const coord_t * coord, const reiser4_key * key,
+                 lock_handle * lh);
+char *extract_name_de(const coord_t * coord, char *buf);
+unsigned extract_file_type_de(const coord_t * coord);
+int add_entry_de(struct inode *dir, coord_t * coord,
+                lock_handle * lh, const struct dentry *name,
+                reiser4_dir_entry_desc * entry);
+int rem_entry_de(struct inode *dir, const struct qstr *name, coord_t * coord,
+                lock_handle * lh, reiser4_dir_entry_desc * entry);
+int max_name_len_de(const struct inode *dir);
+
+int de_rem_and_shrink(struct inode *dir, coord_t * coord, int length);
+
+char *extract_dent_name(const coord_t * coord,
+                       directory_entry_format * dent, char *buf);
+
+#if REISER4_LARGE_KEY
+#define DE_NAME_BUF_LEN (24)
+#else
+#define DE_NAME_BUF_LEN (16)
+#endif
+
+/* __FS_REISER4_PLUGIN_DIRECTORY_ENTRY_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/static_stat.c linux-2.6.20/fs/reiser4/plugin/item/static_stat.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/static_stat.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/static_stat.c   2007-05-06 14:50:43.823014469 +0400
@@ -0,0 +1,1107 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* stat data manipulation. */
+
+#include "../../forward.h"
+#include "../../super.h"
+#include "../../vfs_ops.h"
+#include "../../inode.h"
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../object.h"
+#include "../plugin.h"
+#include "../plugin_header.h"
+#include "static_stat.h"
+#include "item.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>
+
+/* see static_stat.h for explanation */
+
+/* helper function used while we are dumping/loading inode/plugin state
+    to/from the stat-data. */
+
+static void move_on(int *length /* space remaining in stat-data */ ,
+                   char **area /* current coord in stat data */ ,
+                   int size_of /* how many bytes to move forward */ )
+{
+       assert("nikita-615", length != NULL);
+       assert("nikita-616", area != NULL);
+
+       *length -= size_of;
+       *area += size_of;
+
+       assert("nikita-617", *length >= 0);
+}
+
+/* helper function used while loading inode/plugin state from stat-data.
+    Complain if there is less space in stat-data than was expected.
+    Can only happen on disk corruption. */
+static int not_enough_space(struct inode *inode /* object being processed */ ,
+                           const char *where /* error message */ )
+{
+       assert("nikita-618", inode != NULL);
+
+       warning("nikita-619", "Not enough space in %llu while loading %s",
+               (unsigned long long)get_inode_oid(inode), where);
+
+       return RETERR(-EINVAL);
+}
+
+/* helper function used while loading inode/plugin state from
+    stat-data. Call it if invalid plugin id was found. */
+static int unknown_plugin(reiser4_plugin_id id /* invalid id */ ,
+                         struct inode *inode /* object being processed */ )
+{
+       warning("nikita-620", "Unknown plugin %i in %llu",
+               id, (unsigned long long)get_inode_oid(inode));
+
+       return RETERR(-EINVAL);
+}
+
+/* this is installed as ->init_inode() method of
+    item_plugins[ STATIC_STAT_DATA_IT ] (fs/reiser4/plugin/item/item.c).
+    Copies data from on-disk stat-data format into inode.
+    Handles stat-data extensions. */
+/* was sd_load */
+int init_inode_static_sd(struct inode *inode /* object being processed */ ,
+                        char *sd /* stat-data body */ ,
+                        int len /* length of stat-data */ )
+{
+       int result;
+       int bit;
+       int chunk;
+       __u16 mask;
+       __u64 bigmask;
+       reiser4_stat_data_base *sd_base;
+       reiser4_inode *state;
+
+       assert("nikita-625", inode != NULL);
+       assert("nikita-626", sd != NULL);
+
+       result = 0;
+       sd_base = (reiser4_stat_data_base *) sd;
+       state = reiser4_inode_data(inode);
+       mask = le16_to_cpu(get_unaligned(&sd_base->extmask));
+       bigmask = mask;
+       reiser4_inode_set_flag(inode, REISER4_SDLEN_KNOWN);
+
+       move_on(&len, &sd, sizeof *sd_base);
+       for (bit = 0, chunk = 0;
+            mask != 0 || bit <= LAST_IMPORTANT_SD_EXTENSION;
+            ++bit, mask >>= 1) {
+               if (((bit + 1) % 16) != 0) {
+                       /* handle extension */
+                       sd_ext_plugin *sdplug;
+
+                       if (bit >= LAST_SD_EXTENSION) {
+                               warning("vpf-1904",
+                                       "No such extension %i in inode %llu",
+                                       bit,
+                                       (unsigned long long)
+                                       get_inode_oid(inode));
+
+                               result = RETERR(-EINVAL);
+                               break;
+                       }
+
+                       sdplug = sd_ext_plugin_by_id(bit);
+                       if (sdplug == NULL) {
+                               warning("nikita-627",
+                                       "No such extension %i in inode %llu",
+                                       bit,
+                                       (unsigned long long)
+                                       get_inode_oid(inode));
+
+                               result = RETERR(-EINVAL);
+                               break;
+                       }
+                       if (mask & 1) {
+                               assert("nikita-628", sdplug->present);
+                               /* alignment is not supported in node layout
+                                  plugin yet.
+                                  result = align( inode, &len, &sd,
+                                  sdplug -> alignment );
+                                  if( result != 0 )
+                                  return result; */
+                               result = sdplug->present(inode, &sd, &len);
+                       } else if (sdplug->absent != NULL)
+                               result = sdplug->absent(inode);
+                       if (result)
+                               break;
+                       /* else, we are looking at the last bit in 16-bit
+                          portion of bitmask */
+               } else if (mask & 1) {
+                       /* next portion of bitmask */
+                       if (len < (int)sizeof(d16)) {
+                               warning("nikita-629",
+                                       "No space for bitmap in inode %llu",
+                                       (unsigned long long)
+                                       get_inode_oid(inode));
+
+                               result = RETERR(-EINVAL);
+                               break;
+                       }
+                       mask = le16_to_cpu(get_unaligned((d16 *)sd));
+                       bigmask <<= 16;
+                       bigmask |= mask;
+                       move_on(&len, &sd, sizeof(d16));
+                       ++chunk;
+                       if (chunk == 3) {
+                               if (!(mask & 0x8000)) {
+                                       /* clear last bit */
+                                       mask &= ~0x8000;
+                                       continue;
+                               }
+                               /* too much */
+                               warning("nikita-630",
+                                       "Too many extensions in %llu",
+                                       (unsigned long long)
+                                       get_inode_oid(inode));
+
+                               result = RETERR(-EINVAL);
+                               break;
+                       }
+               } else
+                       /* bitmask exhausted */
+                       break;
+       }
+       state->extmask = bigmask;
+       /* common initialisations */
+       if (len - (bit / 16 * sizeof(d16)) > 0) {
+               /* alignment in save_len_static_sd() is taken into account
+                  -edward */
+               warning("nikita-631", "unused space in inode %llu",
+                       (unsigned long long)get_inode_oid(inode));
+       }
+
+       return result;
+}
+
+/* estimates size of stat-data required to store inode.
+    Installed as ->save_len() method of
+    item_plugins[ STATIC_STAT_DATA_IT ] (fs/reiser4/plugin/item/item.c). */
+/* was sd_len */
+int save_len_static_sd(struct inode *inode /* object being processed */ )
+{
+       unsigned int result;
+       __u64 mask;
+       int bit;
+
+       assert("nikita-632", inode != NULL);
+
+       result = sizeof(reiser4_stat_data_base);
+       mask = reiser4_inode_data(inode)->extmask;
+       for (bit = 0; mask != 0; ++bit, mask >>= 1) {
+               if (mask & 1) {
+                       sd_ext_plugin *sdplug;
+
+                       sdplug = sd_ext_plugin_by_id(bit);
+                       assert("nikita-633", sdplug != NULL);
+                       /* no aligment support
+                          result +=
+                          round_up( result, sdplug -> alignment ) - result; */
+                       result += sdplug->save_len(inode);
+               }
+       }
+       result += bit / 16 * sizeof(d16);
+       return result;
+}
+
+/* saves inode into stat-data.
+    Installed as ->save() method of
+    item_plugins[ STATIC_STAT_DATA_IT ] (fs/reiser4/plugin/item/item.c). */
+/* was sd_save */
+int save_static_sd(struct inode *inode /* object being processed */ ,
+                  char **area /* where to save stat-data */ )
+{
+       int result;
+       __u64 emask;
+       int bit;
+       unsigned int len;
+       reiser4_stat_data_base *sd_base;
+
+       assert("nikita-634", inode != NULL);
+       assert("nikita-635", area != NULL);
+
+       result = 0;
+       emask = reiser4_inode_data(inode)->extmask;
+       sd_base = (reiser4_stat_data_base *) * area;
+       put_unaligned(cpu_to_le16((__u16)(emask & 0xffff)), &sd_base->extmask);
+       /*cputod16((unsigned)(emask & 0xffff), &sd_base->extmask);*/
+
+       *area += sizeof *sd_base;
+       len = 0xffffffffu;
+       for (bit = 0; emask != 0; ++bit, emask >>= 1) {
+               if (emask & 1) {
+                       if ((bit + 1) % 16 != 0) {
+                               sd_ext_plugin *sdplug;
+                               sdplug = sd_ext_plugin_by_id(bit);
+                               assert("nikita-636", sdplug != NULL);
+                               /* no alignment support yet
+                                  align( inode, &len, area,
+                                  sdplug -> alignment ); */
+                               result = sdplug->save(inode, area);
+                               if (result)
+                                       break;
+                       } else {
+                               put_unaligned(cpu_to_le16((__u16)(emask & 0xffff)),
+                                             (d16 *)(*area));
+                               /*cputod16((unsigned)(emask & 0xffff),
+                                 (d16 *) * area);*/
+                               *area += sizeof(d16);
+                       }
+               }
+       }
+       return result;
+}
+
+/* stat-data extension handling functions. */
+
+static int present_lw_sd(struct inode *inode /* object being processed */ ,
+                        char **area /* position in stat-data */ ,
+                        int *len /* remaining length */ )
+{
+       if (*len >= (int)sizeof(reiser4_light_weight_stat)) {
+               reiser4_light_weight_stat *sd_lw;
+
+               sd_lw = (reiser4_light_weight_stat *) * area;
+
+               inode->i_mode = le16_to_cpu(get_unaligned(&sd_lw->mode));
+               inode->i_nlink = le32_to_cpu(get_unaligned(&sd_lw->nlink));
+               inode->i_size = le64_to_cpu(get_unaligned(&sd_lw->size));
+               if ((inode->i_mode & S_IFMT) == (S_IFREG | S_IFIFO)) {
+                       inode->i_mode &= ~S_IFIFO;
+                       warning("", "partially converted file is encountered");
+                       reiser4_inode_set_flag(inode, REISER4_PART_MIXED);
+               }
+               move_on(len, area, sizeof *sd_lw);
+               return 0;
+       } else
+               return not_enough_space(inode, "lw sd");
+}
+
+static int save_len_lw_sd(struct inode *inode UNUSED_ARG       /* object being
+                                                                * processed */ )
+{
+       return sizeof(reiser4_light_weight_stat);
+}
+
+static int save_lw_sd(struct inode *inode /* object being processed */ ,
+                     char **area /* position in stat-data */ )
+{
+       reiser4_light_weight_stat *sd;
+       mode_t delta;
+
+       assert("nikita-2705", inode != NULL);
+       assert("nikita-2706", area != NULL);
+       assert("nikita-2707", *area != NULL);
+
+       sd = (reiser4_light_weight_stat *) * area;
+
+       delta = (reiser4_inode_get_flag(inode,
+                                       REISER4_PART_MIXED) ? S_IFIFO : 0);
+       put_unaligned(cpu_to_le16(inode->i_mode | delta), &sd->mode);
+       put_unaligned(cpu_to_le32(inode->i_nlink), &sd->nlink);
+       put_unaligned(cpu_to_le64((__u64) inode->i_size), &sd->size);
+       *area += sizeof *sd;
+       return 0;
+}
+
+static int present_unix_sd(struct inode *inode /* object being processed */ ,
+                          char **area /* position in stat-data */ ,
+                          int *len /* remaining length */ )
+{
+       assert("nikita-637", inode != NULL);
+       assert("nikita-638", area != NULL);
+       assert("nikita-639", *area != NULL);
+       assert("nikita-640", len != NULL);
+       assert("nikita-641", *len > 0);
+
+       if (*len >= (int)sizeof(reiser4_unix_stat)) {
+               reiser4_unix_stat *sd;
+
+               sd = (reiser4_unix_stat *) * area;
+
+               inode->i_uid = le32_to_cpu(get_unaligned(&sd->uid));
+               inode->i_gid = le32_to_cpu(get_unaligned(&sd->gid));
+               inode->i_atime.tv_sec = le32_to_cpu(get_unaligned(&sd->atime));
+               inode->i_mtime.tv_sec = le32_to_cpu(get_unaligned(&sd->mtime));
+               inode->i_ctime.tv_sec = le32_to_cpu(get_unaligned(&sd->ctime));
+               if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode))
+                       inode->i_rdev = le64_to_cpu(get_unaligned(&sd->u.rdev));
+               else
+                       inode_set_bytes(inode, (loff_t) le64_to_cpu(get_unaligned(&sd->u.bytes)));
+               move_on(len, area, sizeof *sd);
+               return 0;
+       } else
+               return not_enough_space(inode, "unix sd");
+}
+
+static int absent_unix_sd(struct inode *inode /* object being processed */ )
+{
+       inode->i_uid = get_super_private(inode->i_sb)->default_uid;
+       inode->i_gid = get_super_private(inode->i_sb)->default_gid;
+       inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
+       inode_set_bytes(inode, inode->i_size);
+       /* mark inode as lightweight, so that caller (lookup_common) will
+          complete initialisation by copying [ug]id from a parent. */
+       reiser4_inode_set_flag(inode, REISER4_LIGHT_WEIGHT);
+       return 0;
+}
+
+/* Audited by: green(2002.06.14) */
+static int save_len_unix_sd(struct inode *inode UNUSED_ARG     /* object being
+                                                                * processed */ )
+{
+       return sizeof(reiser4_unix_stat);
+}
+
+static int save_unix_sd(struct inode *inode /* object being processed */ ,
+                       char **area /* position in stat-data */ )
+{
+       reiser4_unix_stat *sd;
+
+       assert("nikita-642", inode != NULL);
+       assert("nikita-643", area != NULL);
+       assert("nikita-644", *area != NULL);
+
+       sd = (reiser4_unix_stat *) * area;
+       put_unaligned(cpu_to_le32(inode->i_uid), &sd->uid);
+       put_unaligned(cpu_to_le32(inode->i_gid), &sd->gid);
+       put_unaligned(cpu_to_le32((__u32) inode->i_atime.tv_sec), &sd->atime);
+       put_unaligned(cpu_to_le32((__u32) inode->i_ctime.tv_sec), &sd->ctime);
+       put_unaligned(cpu_to_le32((__u32) inode->i_mtime.tv_sec), &sd->mtime);
+       if (S_ISBLK(inode->i_mode) || S_ISCHR(inode->i_mode))
+               put_unaligned(cpu_to_le64(inode->i_rdev), &sd->u.rdev);
+       else
+               put_unaligned(cpu_to_le64((__u64) inode_get_bytes(inode)), &sd->u.bytes);
+       *area += sizeof *sd;
+       return 0;
+}
+
+static int
+present_large_times_sd(struct inode *inode /* object being processed */ ,
+                      char **area /* position in stat-data */ ,
+                      int *len /* remaining length */ )
+{
+       if (*len >= (int)sizeof(reiser4_large_times_stat)) {
+               reiser4_large_times_stat *sd_lt;
+
+               sd_lt = (reiser4_large_times_stat *) * area;
+
+               inode->i_atime.tv_nsec = le32_to_cpu(get_unaligned(&sd_lt->atime));
+               inode->i_mtime.tv_nsec = le32_to_cpu(get_unaligned(&sd_lt->mtime));
+               inode->i_ctime.tv_nsec = le32_to_cpu(get_unaligned(&sd_lt->ctime));
+
+               move_on(len, area, sizeof *sd_lt);
+               return 0;
+       } else
+               return not_enough_space(inode, "large times sd");
+}
+
+static int
+save_len_large_times_sd(struct inode *inode UNUSED_ARG
+                       /* object being processed */ )
+{
+       return sizeof(reiser4_large_times_stat);
+}
+
+static int
+save_large_times_sd(struct inode *inode /* object being processed */ ,
+                   char **area /* position in stat-data */ )
+{
+       reiser4_large_times_stat *sd;
+
+       assert("nikita-2817", inode != NULL);
+       assert("nikita-2818", area != NULL);
+       assert("nikita-2819", *area != NULL);
+
+       sd = (reiser4_large_times_stat *) * area;
+
+       put_unaligned(cpu_to_le32((__u32) inode->i_atime.tv_nsec), &sd->atime);
+       put_unaligned(cpu_to_le32((__u32) inode->i_ctime.tv_nsec), &sd->ctime);
+       put_unaligned(cpu_to_le32((__u32) inode->i_mtime.tv_nsec), &sd->mtime);
+
+       *area += sizeof *sd;
+       return 0;
+}
+
+/* symlink stat data extension */
+
+/* allocate memory for symlink target and attach it to inode->i_private */
+static int
+symlink_target_to_inode(struct inode *inode, const char *target, int len)
+{
+       assert("vs-845", inode->i_private == NULL);
+       assert("vs-846", !reiser4_inode_get_flag(inode,
+                                                REISER4_GENERIC_PTR_USED));
+       /* FIXME-VS: this is prone to deadlock. Not more than other similar
+          places, though */
+       inode->i_private = kmalloc((size_t) len + 1,
+                                  reiser4_ctx_gfp_mask_get());
+       if (!inode->i_private)
+               return RETERR(-ENOMEM);
+
+       memcpy((char *)(inode->i_private), target, (size_t) len);
+       ((char *)(inode->i_private))[len] = 0;
+       reiser4_inode_set_flag(inode, REISER4_GENERIC_PTR_USED);
+       return 0;
+}
+
+/* this is called on read_inode. There is nothing to do actually, but some
+   sanity checks */
+static int present_symlink_sd(struct inode *inode, char **area, int *len)
+{
+       int result;
+       int length;
+       reiser4_symlink_stat *sd;
+
+       length = (int)inode->i_size;
+       /*
+        * *len is number of bytes in stat data item from *area to the end of
+        * item. It must be not less than size of symlink + 1 for ending 0
+        */
+       if (length > *len)
+               return not_enough_space(inode, "symlink");
+
+       if (*(*area + length) != 0) {
+               warning("vs-840", "Symlink is not zero terminated");
+               return RETERR(-EIO);
+       }
+
+       sd = (reiser4_symlink_stat *) * area;
+       result = symlink_target_to_inode(inode, sd->body, length);
+
+       move_on(len, area, length + 1);
+       return result;
+}
+
+static int save_len_symlink_sd(struct inode *inode)
+{
+       return inode->i_size + 1;
+}
+
+/* this is called on create and update stat data. Do nothing on update but
+   update @area */
+static int save_symlink_sd(struct inode *inode, char **area)
+{
+       int result;
+       int length;
+       reiser4_symlink_stat *sd;
+
+       length = (int)inode->i_size;
+       /* inode->i_size must be set already */
+       assert("vs-841", length);
+
+       result = 0;
+       sd = (reiser4_symlink_stat *) * area;
+       if (!reiser4_inode_get_flag(inode, REISER4_GENERIC_PTR_USED)) {
+               const char *target;
+
+               target = (const char *)(inode->i_private);
+               inode->i_private = NULL;
+
+               result = symlink_target_to_inode(inode, target, length);
+
+               /* copy symlink to stat data */
+               memcpy(sd->body, target, (size_t) length);
+               (*area)[length] = 0;
+       } else {
+               /* there is nothing to do in update but move area */
+               assert("vs-844",
+                      !memcmp(inode->i_private, sd->body,
+                              (size_t) length + 1));
+       }
+
+       *area += (length + 1);
+       return result;
+}
+
+static int present_flags_sd(struct inode *inode /* object being processed */ ,
+                           char **area /* position in stat-data */ ,
+                           int *len /* remaining length */ )
+{
+       assert("nikita-645", inode != NULL);
+       assert("nikita-646", area != NULL);
+       assert("nikita-647", *area != NULL);
+       assert("nikita-648", len != NULL);
+       assert("nikita-649", *len > 0);
+
+       if (*len >= (int)sizeof(reiser4_flags_stat)) {
+               reiser4_flags_stat *sd;
+
+               sd = (reiser4_flags_stat *) * area;
+               inode->i_flags = le32_to_cpu(get_unaligned(&sd->flags));
+               move_on(len, area, sizeof *sd);
+               return 0;
+       } else
+               return not_enough_space(inode, "generation and attrs");
+}
+
+/* Audited by: green(2002.06.14) */
+static int save_len_flags_sd(struct inode *inode UNUSED_ARG    /* object being
+                                                                * processed */ )
+{
+       return sizeof(reiser4_flags_stat);
+}
+
+static int save_flags_sd(struct inode *inode /* object being processed */ ,
+                        char **area /* position in stat-data */ )
+{
+       reiser4_flags_stat *sd;
+
+       assert("nikita-650", inode != NULL);
+       assert("nikita-651", area != NULL);
+       assert("nikita-652", *area != NULL);
+
+       sd = (reiser4_flags_stat *) * area;
+       put_unaligned(cpu_to_le32(inode->i_flags), &sd->flags);
+       *area += sizeof *sd;
+       return 0;
+}
+
+static int absent_plugin_sd(struct inode *inode);
+static int present_plugin_sd(struct inode *inode /* object being processed */ ,
+                            char **area /* position in stat-data */ ,
+                            int *len /* remaining length */,
+                            int is_pset /* 1 if plugin set, 0 if heir set. */)
+{
+       reiser4_plugin_stat *sd;
+       reiser4_plugin *plugin;
+       reiser4_inode *info;
+       int i;
+       __u16 mask;
+       int result;
+       int num_of_plugins;
+
+       assert("nikita-653", inode != NULL);
+       assert("nikita-654", area != NULL);
+       assert("nikita-655", *area != NULL);
+       assert("nikita-656", len != NULL);
+       assert("nikita-657", *len > 0);
+
+       if (*len < (int)sizeof(reiser4_plugin_stat))
+               return not_enough_space(inode, "plugin");
+
+       sd = (reiser4_plugin_stat *) * area;
+       info = reiser4_inode_data(inode);
+
+       mask = 0;
+       num_of_plugins = le16_to_cpu(get_unaligned(&sd->plugins_no));
+       move_on(len, area, sizeof *sd);
+       result = 0;
+       for (i = 0; i < num_of_plugins; ++i) {
+               reiser4_plugin_slot *slot;
+               reiser4_plugin_type type;
+               pset_member memb;
+
+               slot = (reiser4_plugin_slot *) * area;
+               if (*len < (int)sizeof *slot)
+                       return not_enough_space(inode, "additional plugin");
+
+               memb = le16_to_cpu(get_unaligned(&slot->pset_memb));
+               type = aset_member_to_type_unsafe(memb);
+
+               if (type == REISER4_PLUGIN_TYPES) {
+                       warning("nikita-3502",
+                               "wrong %s member (%i) for %llu", is_pset ?
+                               "pset" : "hset", memb,
+                               (unsigned long long)get_inode_oid(inode));
+                       return RETERR(-EINVAL);
+               }
+               plugin = plugin_by_disk_id(reiser4_tree_by_inode(inode),
+                                          type, &slot->id);
+               if (plugin == NULL)
+                       return unknown_plugin(le16_to_cpu(get_unaligned(&slot->id)), inode);
+
+               /* plugin is loaded into inode, mark this into inode's
+                  bitmask of loaded non-standard plugins */
+               if (!(mask & (1 << memb))) {
+                       mask |= (1 << memb);
+               } else {
+                       warning("nikita-658", "duplicate plugin for %llu",
+                               (unsigned long long)get_inode_oid(inode));
+                       return RETERR(-EINVAL);
+               }
+               move_on(len, area, sizeof *slot);
+               /* load plugin data, if any */
+               if (plugin->h.pops != NULL && plugin->h.pops->load)
+                       result = plugin->h.pops->load(inode, plugin, area, len);
+               else
+                       result = aset_set_unsafe(is_pset ? &info->pset :
+                                                &info->hset, memb, plugin);
+               if (result)
+                       return result;
+       }
+       if (is_pset) {
+               /* if object plugin wasn't loaded from stat-data, guess it by
+                  mode bits */
+               plugin = file_plugin_to_plugin(inode_file_plugin(inode));
+               if (plugin == NULL)
+                       result = absent_plugin_sd(inode);
+               info->plugin_mask = mask;
+       } else
+               info->heir_mask = mask;
+
+       return result;
+}
+
+static int present_pset_sd(struct inode *inode, char **area, int *len) {
+       return present_plugin_sd(inode, area, len, 1 /* pset */);
+}
+
+/* Determine object plugin for @inode based on i_mode.
+
+   Many objects in reiser4 file system are controlled by standard object
+   plugins that emulate traditional unix objects: unix file, directory, symlink, fifo, and so on.
+
+   For such files we don't explicitly store plugin id in object stat
+   data. Rather required plugin is guessed from mode bits, where file "type"
+   is encoded (see stat(2)).
+*/
+static int
+guess_plugin_by_mode(struct inode *inode /* object to guess plugins for */ )
+{
+       int fplug_id;
+       int dplug_id;
+       reiser4_inode *info;
+
+       assert("nikita-736", inode != NULL);
+
+       dplug_id = fplug_id = -1;
+
+       switch (inode->i_mode & S_IFMT) {
+       case S_IFSOCK:
+       case S_IFBLK:
+       case S_IFCHR:
+       case S_IFIFO:
+               fplug_id = SPECIAL_FILE_PLUGIN_ID;
+               break;
+       case S_IFLNK:
+               fplug_id = SYMLINK_FILE_PLUGIN_ID;
+               break;
+       case S_IFDIR:
+               fplug_id = DIRECTORY_FILE_PLUGIN_ID;
+               dplug_id = HASHED_DIR_PLUGIN_ID;
+               break;
+       default:
+               warning("nikita-737", "wrong file mode: %o", inode->i_mode);
+               return RETERR(-EIO);
+       case S_IFREG:
+               fplug_id = UNIX_FILE_PLUGIN_ID;
+               break;
+       }
+       info = reiser4_inode_data(inode);
+       set_plugin(&info->pset, PSET_FILE, (fplug_id >= 0) ?
+                  plugin_by_id(REISER4_FILE_PLUGIN_TYPE, fplug_id) : NULL);
+       set_plugin(&info->pset, PSET_DIR, (dplug_id >= 0) ?
+                  plugin_by_id(REISER4_DIR_PLUGIN_TYPE, dplug_id) : NULL);
+       return 0;
+}
+
+/* Audited by: green(2002.06.14) */
+static int absent_plugin_sd(struct inode *inode /* object being processed */ )
+{
+       int result;
+
+       assert("nikita-659", inode != NULL);
+
+       result = guess_plugin_by_mode(inode);
+       /* if mode was wrong, guess_plugin_by_mode() returns "regular file",
+          but setup_inode_ops() will call make_bad_inode().
+          Another, more logical but bit more complex solution is to add
+          "bad-file plugin". */
+       /* FIXME-VS: activate was called here */
+       return result;
+}
+
+/* helper function for plugin_sd_save_len(): calculate how much space
+    required to save state of given plugin */
+/* Audited by: green(2002.06.14) */
+static int len_for(reiser4_plugin * plugin /* plugin to save */ ,
+                  struct inode *inode /* object being processed */ ,
+                  pset_member memb,
+                  int len, int is_pset)
+{
+       reiser4_inode *info;
+       assert("nikita-661", inode != NULL);
+
+       if (plugin == NULL)
+               return len;
+
+       info = reiser4_inode_data(inode);
+       if (is_pset ?
+           info->plugin_mask & (1 << memb) :
+           info->heir_mask & (1 << memb)) {
+               len += sizeof(reiser4_plugin_slot);
+               if (plugin->h.pops && plugin->h.pops->save_len != NULL) {
+                       /* non-standard plugin, call method */
+                       /* commented as it is incompatible with alignment
+                        * policy in save_plug() -edward */
+                       /* len = round_up(len, plugin->h.pops->alignment); */
+                       len += plugin->h.pops->save_len(inode, plugin);
+               }
+       }
+       return len;
+}
+
+/* calculate how much space is required to save state of all plugins,
+    associated with inode */
+static int save_len_plugin_sd(struct inode *inode /* object being processed */,
+                             int is_pset)
+{
+       int len;
+       int last;
+       reiser4_inode *state;
+       pset_member memb;
+
+       assert("nikita-663", inode != NULL);
+
+       state = reiser4_inode_data(inode);
+
+       /* common case: no non-standard plugins */
+       if (is_pset ? state->plugin_mask == 0 : state->heir_mask == 0)
+               return 0;
+       len = sizeof(reiser4_plugin_stat);
+       last = PSET_LAST;
+
+       for (memb = 0; memb < last; ++memb) {
+             len = len_for(aset_get(is_pset ? state->pset : state->hset, memb),
+                           inode, memb, len, is_pset);
+       }
+       assert("nikita-664", len > (int)sizeof(reiser4_plugin_stat));
+       return len;
+}
+
+static int save_len_pset_sd(struct inode *inode) {
+       return save_len_plugin_sd(inode, 1 /* pset */);
+}
+
+/* helper function for plugin_sd_save(): save plugin, associated with
+    inode. */
+static int save_plug(reiser4_plugin * plugin /* plugin to save */ ,
+                    struct inode *inode /* object being processed */ ,
+                    int memb /* what element of pset is saved */ ,
+                    char **area /* position in stat-data */ ,
+                    int *count /* incremented if plugin were actually saved. */,
+                    int is_pset /* 1 for plugin set, 0 for heir set */)
+{
+       reiser4_plugin_slot *slot;
+       int fake_len;
+       int result;
+
+       assert("nikita-665", inode != NULL);
+       assert("nikita-666", area != NULL);
+       assert("nikita-667", *area != NULL);
+
+       if (plugin == NULL)
+               return 0;
+
+       if (is_pset ?
+           !(reiser4_inode_data(inode)->plugin_mask & (1 << memb)) :
+           !(reiser4_inode_data(inode)->heir_mask & (1 << memb)))
+               return 0;
+       slot = (reiser4_plugin_slot *) * area;
+       put_unaligned(cpu_to_le16(memb), &slot->pset_memb);
+       put_unaligned(cpu_to_le16(plugin->h.id), &slot->id);
+       fake_len = (int)0xffff;
+       move_on(&fake_len, area, sizeof *slot);
+       ++*count;
+       result = 0;
+       if (plugin->h.pops != NULL) {
+               if (plugin->h.pops->save != NULL)
+                       result = plugin->h.pops->save(inode, plugin, area);
+       }
+       return result;
+}
+
+/* save state of all non-standard plugins associated with inode */
+static int save_plugin_sd(struct inode *inode /* object being processed */ ,
+                         char **area /* position in stat-data */,
+                         int is_pset /* 1 for pset, 0 for hset */)
+{
+       int fake_len;
+       int result = 0;
+       int num_of_plugins;
+       reiser4_plugin_stat *sd;
+       reiser4_inode *state;
+       pset_member memb;
+
+       assert("nikita-669", inode != NULL);
+       assert("nikita-670", area != NULL);
+       assert("nikita-671", *area != NULL);
+
+       state = reiser4_inode_data(inode);
+       if (is_pset ? state->plugin_mask == 0 : state->heir_mask == 0)
+               return 0;
+       sd = (reiser4_plugin_stat *) * area;
+       fake_len = (int)0xffff;
+       move_on(&fake_len, area, sizeof *sd);
+
+       num_of_plugins = 0;
+       for (memb = 0; memb < PSET_LAST; ++memb) {
+               result = save_plug(aset_get(is_pset ? state->pset : state->hset,
+                                           memb),
+                                  inode, memb, area, &num_of_plugins, is_pset);
+               if (result != 0)
+                       break;
+       }
+
+       put_unaligned(cpu_to_le16((__u16)num_of_plugins), &sd->plugins_no);
+       return result;
+}
+
+static int save_pset_sd(struct inode *inode, char **area) {
+       return save_plugin_sd(inode, area, 1 /* pset */);
+}
+
+static int present_hset_sd(struct inode *inode, char **area, int *len) {
+       return present_plugin_sd(inode, area, len, 0 /* hset */);
+}
+
+static int save_len_hset_sd(struct inode *inode) {
+       return save_len_plugin_sd(inode, 0 /* pset */);
+}
+
+static int save_hset_sd(struct inode *inode, char **area) {
+       return save_plugin_sd(inode, area, 0 /* hset */);
+}
+
+/* helper function for crypto_sd_present(), crypto_sd_save.
+   Allocates memory for crypto stat, keyid and attaches it to the inode */
+static int extract_crypto_stat (struct inode * inode,
+                               reiser4_crypto_stat * sd)
+{
+       crypto_stat_t * info;
+       assert("edward-11", !inode_crypto_stat(inode));
+       assert("edward-1413",
+              !reiser4_inode_get_flag(inode, REISER4_CRYPTO_STAT_LOADED));
+       /* create and attach a crypto-stat without secret key loaded */
+       info = reiser4_alloc_crypto_stat(inode);
+       if (IS_ERR(info))
+               return PTR_ERR(info);
+       info->keysize = le16_to_cpu(get_unaligned(&sd->keysize));
+       memcpy(info->keyid, sd->keyid, inode_digest_plugin(inode)->fipsize);
+       reiser4_attach_crypto_stat(inode, info);
+       reiser4_inode_set_flag(inode, REISER4_CRYPTO_STAT_LOADED);
+       return 0;
+}
+
+/* crypto stat-data extension */
+
+static int present_crypto_sd(struct inode *inode, char **area, int *len)
+{
+       int result;
+       reiser4_crypto_stat *sd;
+       digest_plugin *dplug = inode_digest_plugin(inode);
+
+       assert("edward-06", dplug != NULL);
+       assert("edward-684", dplug->fipsize);
+       assert("edward-07", area != NULL);
+       assert("edward-08", *area != NULL);
+       assert("edward-09", len != NULL);
+       assert("edward-10", *len > 0);
+
+       if (*len < (int)sizeof(reiser4_crypto_stat)) {
+               return not_enough_space(inode, "crypto-sd");
+       }
+       /* *len is number of bytes in stat data item from *area to the end of
+          item. It must be not less than size of this extension */
+       assert("edward-75", sizeof(*sd) + dplug->fipsize <= *len);
+
+       sd = (reiser4_crypto_stat *) * area;
+       result = extract_crypto_stat(inode, sd);
+       move_on(len, area, sizeof(*sd) + dplug->fipsize);
+
+       return result;
+}
+
+static int save_len_crypto_sd(struct inode *inode)
+{
+       return sizeof(reiser4_crypto_stat) +
+               inode_digest_plugin(inode)->fipsize;
+}
+
+static int save_crypto_sd(struct inode *inode, char **area)
+{
+       int result = 0;
+       reiser4_crypto_stat *sd;
+       crypto_stat_t * info = inode_crypto_stat(inode);
+       digest_plugin *dplug = inode_digest_plugin(inode);
+
+       assert("edward-12", dplug != NULL);
+       assert("edward-13", area != NULL);
+       assert("edward-14", *area != NULL);
+       assert("edward-15", info != NULL);
+       assert("edward-1414", info->keyid != NULL);
+       assert("edward-1415", info->keysize != 0);
+       assert("edward-76", reiser4_inode_data(inode) != NULL);
+
+       if (!reiser4_inode_get_flag(inode, REISER4_CRYPTO_STAT_LOADED)) {
+               /* file is just created */
+               sd = (reiser4_crypto_stat *) *area;
+               /* copy everything but private key to the disk stat-data */
+               put_unaligned(cpu_to_le16(info->keysize), &sd->keysize);
+               memcpy(sd->keyid, info->keyid, (size_t) dplug->fipsize);
+               reiser4_inode_set_flag(inode, REISER4_CRYPTO_STAT_LOADED);
+       }
+       *area += (sizeof(*sd) + dplug->fipsize);
+       return result;
+}
+
+static int eio(struct inode *inode, char **area, int *len)
+{
+       return RETERR(-EIO);
+}
+
+sd_ext_plugin sd_ext_plugins[LAST_SD_EXTENSION] = {
+       [LIGHT_WEIGHT_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = LIGHT_WEIGHT_STAT,
+                       .pops = NULL,
+                       .label = "light-weight sd",
+                       .desc = "sd for light-weight files",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_lw_sd,
+               .absent = NULL,
+               .save_len = save_len_lw_sd,
+               .save = save_lw_sd,
+               .alignment = 8
+       },
+       [UNIX_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = UNIX_STAT,
+                       .pops = NULL,
+                       .label = "unix-sd",
+                       .desc = "unix stat-data fields",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_unix_sd,
+               .absent = absent_unix_sd,
+               .save_len = save_len_unix_sd,
+               .save = save_unix_sd,
+               .alignment = 8
+       },
+       [LARGE_TIMES_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = LARGE_TIMES_STAT,
+                       .pops = NULL,
+                       .label = "64time-sd",
+                       .desc = "nanosecond resolution for times",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_large_times_sd,
+               .absent = NULL,
+               .save_len = save_len_large_times_sd,
+               .save = save_large_times_sd,
+               .alignment = 8
+       },
+       [SYMLINK_STAT] = {
+               /* stat data of symlink has this extension */
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = SYMLINK_STAT,
+                       .pops = NULL,
+                       .label = "symlink-sd",
+                       .desc =
+                       "stat data is appended with symlink name",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_symlink_sd,
+               .absent = NULL,
+               .save_len = save_len_symlink_sd,
+               .save = save_symlink_sd,
+               .alignment = 8
+       },
+       [PLUGIN_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = PLUGIN_STAT,
+                       .pops = NULL,
+                       .label = "plugin-sd",
+                       .desc = "plugin stat-data fields",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_pset_sd,
+               .absent = absent_plugin_sd,
+               .save_len = save_len_pset_sd,
+               .save = save_pset_sd,
+               .alignment = 8
+       },
+       [HEIR_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = HEIR_STAT,
+                       .pops = NULL,
+                       .label = "heir-plugin-sd",
+                       .desc = "heir plugin stat-data fields",
+                       .linkage = {NULL,NULL}
+               },
+               .present = present_hset_sd,
+               .absent = NULL,
+               .save_len = save_len_hset_sd,
+               .save = save_hset_sd,
+               .alignment = 8
+       },
+       [FLAGS_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = FLAGS_STAT,
+                       .pops = NULL,
+                       .label = "flags-sd",
+                       .desc = "inode bit flags",
+                       .linkage = {NULL, NULL}
+               },
+               .present = present_flags_sd,
+               .absent = NULL,
+               .save_len = save_len_flags_sd,
+               .save = save_flags_sd,
+               .alignment = 8
+       },
+       [CAPABILITIES_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = CAPABILITIES_STAT,
+                       .pops = NULL,
+                       .label = "capabilities-sd",
+                       .desc = "capabilities",
+                       .linkage = {NULL, NULL}
+               },
+               .present = eio,
+               .absent = NULL,
+               .save_len = save_len_flags_sd,
+               .save = save_flags_sd,
+               .alignment = 8
+       },
+       [CRYPTO_STAT] = {
+               .h = {
+                       .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+                       .id = CRYPTO_STAT,
+                       .pops = NULL,
+                       .label = "crypto-sd",
+                       .desc = "secret key size and id",
+                       .linkage = {NULL, NULL}
+               },
+               .present = present_crypto_sd,
+               .absent = NULL,
+               .save_len = save_len_crypto_sd,
+               .save = save_crypto_sd,
+               .alignment = 8
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/static_stat.h linux-2.6.20/fs/reiser4/plugin/item/static_stat.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/static_stat.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/static_stat.h   2007-05-06 14:50:43.823014469 +0400
@@ -0,0 +1,224 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* This describes the static_stat item, used to hold all information needed by the stat() syscall.
+
+In the case where each file has not less than the fields needed by the
+stat() syscall, it is more compact to store those fields in this
+struct.
+
+If this item does not exist, then all stats are dynamically resolved.
+At the moment, we either resolve all stats dynamically or all of them
+statically.  If you think this is not fully optimal, and the rest of
+reiser4 is working, then fix it...:-)
+
+*/
+
+#if !defined( __FS_REISER4_PLUGIN_ITEM_STATIC_STAT_H__ )
+#define __FS_REISER4_PLUGIN_ITEM_STATIC_STAT_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+
+#include <linux/fs.h>          /* for struct inode */
+
+/* Stat data layout: goals and implementation.
+
+   We want to be able to have lightweight files which have complete flexibility in what semantic metadata is attached to
+   them, including not having semantic metadata attached to them.
+
+   There is one problem with doing that, which is that if in fact you have exactly the same metadata for most files you
+   want to store, then it takes more space to store that metadata in a dynamically sized structure than in a statically
+   sized structure because the statically sized structure knows without recording it what the names and lengths of the
+   attributes are.
+
+   This leads to a natural compromise, which is to special case those files which have simply the standard unix file
+   attributes, and only employ the full dynamic stat data mechanism for those files that differ from the standard unix
+   file in their use of file attributes.
+
+   Yet this compromise deserves to be compromised a little.
+
+   We accommodate the case where you have no more than the standard unix file attributes by using an "extension
+   bitmask": each bit in it indicates presence or absence of or particular stat data extension (see sd_ext_bits enum).
+
+   If the first bit of the extension bitmask bit is 0, we have light-weight file whose attributes are either inherited
+   from parent directory (as uid, gid) or initialised to some sane values.
+
+   To capitalize on existing code infrastructure, extensions are
+   implemented as plugins of type REISER4_SD_EXT_PLUGIN_TYPE.
+   Each stat-data extension plugin implements four methods:
+
+    ->present() called by sd_load() when this extension is found in stat-data
+    ->absent() called by sd_load() when this extension is not found in stat-data
+    ->save_len() called by sd_len() to calculate total length of stat-data
+    ->save() called by sd_save() to store extension data into stat-data
+
+    Implementation is in fs/reiser4/plugin/item/static_stat.c
+*/
+
+/* stat-data extension. Please order this by presumed frequency of use */
+typedef enum {
+       /* support for light-weight files */
+       LIGHT_WEIGHT_STAT,
+       /* data required to implement unix stat(2) call. Layout is in
+          reiser4_unix_stat. If this is not present, file is light-weight */
+       UNIX_STAT,
+       /* this contains additional set of 32bit [anc]time fields to implement
+          nanosecond resolution. Layout is in reiser4_large_times_stat. Usage
+          if this extension is governed by 32bittimes mount option. */
+       LARGE_TIMES_STAT,
+       /* stat data has link name included */
+       SYMLINK_STAT,
+       /* on-disk slots of non-standard plugins for main plugin table
+          (@reiser4_inode->pset), that is, plugins that cannot be deduced
+          from file mode bits), for example, aggregation, interpolation etc. */
+       PLUGIN_STAT,
+       /* this extension contains persistent inode flags. These flags are
+          single bits: immutable, append, only, etc. Layout is in
+          reiser4_flags_stat. */
+       FLAGS_STAT,
+       /* this extension contains capabilities sets, associated with this
+          file. Layout is in reiser4_capabilities_stat */
+       CAPABILITIES_STAT,
+       /* this extension contains size and public id of the secret key.
+          Layout is in reiser4_crypto_stat */
+       CRYPTO_STAT,
+       /* on-disk slots of non-default plugins for inheritance, which
+          are extracted to special plugin table (@reiser4_inode->hset).
+          By default, children of the object will inherit plugins from
+          its main plugin table (pset). */
+       HEIR_STAT,
+       LAST_SD_EXTENSION,
+       /*
+        * init_inode_static_sd() iterates over extension mask until all
+        * non-zero bits are processed. This means, that neither ->present(),
+        * nor ->absent() methods will be called for stat-data extensions that
+        * go after last present extension. But some basic extensions, we want
+        * either ->absent() or ->present() method to be called, because these
+        * extensions set up something in inode even when they are not
+        * present. This is what LAST_IMPORTANT_SD_EXTENSION is for: for all
+        * extensions before and including LAST_IMPORTANT_SD_EXTENSION either
+        * ->present(), or ->absent() method will be called, independently of
+        * what other extensions are present.
+        */
+       LAST_IMPORTANT_SD_EXTENSION = PLUGIN_STAT
+} sd_ext_bits;
+
+/* minimal stat-data. This allows to support light-weight files. */
+typedef struct reiser4_stat_data_base {
+       /*  0 */ __le16 extmask;
+       /*  2 */
+} PACKED reiser4_stat_data_base;
+
+typedef struct reiser4_light_weight_stat {
+       /*  0 */ __le16 mode;
+       /*  2 */ __le32 nlink;
+       /*  6 */ __le64 size;
+       /* size in bytes */
+       /* 14 */
+} PACKED reiser4_light_weight_stat;
+
+typedef struct reiser4_unix_stat {
+       /* owner id */
+       /*  0 */ __le32 uid;
+       /* group id */
+       /*  4 */ __le32 gid;
+       /* access time */
+       /*  8 */ __le32 atime;
+       /* modification time */
+       /* 12 */ __le32 mtime;
+       /* change time */
+       /* 16 */ __le32 ctime;
+       union {
+               /* minor:major for device files */
+               /* 20 */ __le64 rdev;
+               /* bytes used by file */
+               /* 20 */ __le64 bytes;
+       } u;
+       /* 28 */
+} PACKED reiser4_unix_stat;
+
+/* symlink stored as part of inode */
+typedef struct reiser4_symlink_stat {
+       char body[0];
+} PACKED reiser4_symlink_stat;
+
+typedef struct reiser4_plugin_slot {
+       /*  0 */ __le16 pset_memb;
+       /*  2 */ __le16 id;
+       /*  4 *//* here plugin stores its persistent state */
+} PACKED reiser4_plugin_slot;
+
+/* stat-data extension for files with non-standard plugin. */
+typedef struct reiser4_plugin_stat {
+       /* number of additional plugins, associated with this object */
+       /*  0 */ __le16 plugins_no;
+       /*  2 */ reiser4_plugin_slot slot[0];
+       /*  2 */
+} PACKED reiser4_plugin_stat;
+
+/* stat-data extension for inode flags. Currently it is just fixed-width 32
+ * bit mask. If need arise, this can be replaced with variable width
+ * bitmask. */
+typedef struct reiser4_flags_stat {
+       /*  0 */ __le32 flags;
+       /*  4 */
+} PACKED reiser4_flags_stat;
+
+typedef struct reiser4_capabilities_stat {
+       /*  0 */ __le32 effective;
+       /*  8 */ __le32 permitted;
+       /* 16 */
+} PACKED reiser4_capabilities_stat;
+
+typedef struct reiser4_cluster_stat {
+/* this defines cluster size (an attribute of cryptcompress objects) as PAGE_SIZE << cluster shift */
+       /* 0 */ d8 cluster_shift;
+       /* 1 */
+} PACKED reiser4_cluster_stat;
+
+typedef struct reiser4_crypto_stat {
+       /* secret key size, bits */
+       /*  0 */ d16 keysize;
+       /* secret key id */
+       /*  2 */ d8 keyid[0];
+       /* 2 */
+} PACKED reiser4_crypto_stat;
+
+typedef struct reiser4_large_times_stat {
+       /* access time */
+       /* 0 */ d32 atime;
+       /* modification time */
+       /* 4 */ d32 mtime;
+       /* change time */
+       /* 8 */ d32 ctime;
+       /* 12 */
+} PACKED reiser4_large_times_stat;
+
+/* this structure is filled by sd_item_stat */
+typedef struct sd_stat {
+       int dirs;
+       int files;
+       int others;
+} sd_stat;
+
+/* plugin->item.common.* */
+extern void print_sd(const char *prefix, coord_t * coord);
+extern void item_stat_static_sd(const coord_t * coord, void *vp);
+
+/* plugin->item.s.sd.* */
+extern int init_inode_static_sd(struct inode *inode, char *sd, int len);
+extern int save_len_static_sd(struct inode *inode);
+extern int save_static_sd(struct inode *inode, char **area);
+
+/* __FS_REISER4_PLUGIN_ITEM_STATIC_STAT_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/tail.c linux-2.6.20/fs/reiser4/plugin/item/tail.c
--- linux-2.6.20.orig/fs/reiser4/plugin/item/tail.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/tail.c  2007-05-06 14:50:43.823014469 +0400
@@ -0,0 +1,812 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "item.h"
+#include "../../inode.h"
+#include "../../page_cache.h"
+#include "../../carry.h"
+#include "../../vfs_ops.h"
+
+#include <linux/quotaops.h>
+#include <asm/uaccess.h>
+#include <linux/swap.h>
+#include <linux/writeback.h>
+
+/* plugin->u.item.b.max_key_inside */
+reiser4_key *max_key_inside_tail(const coord_t *coord, reiser4_key *key)
+{
+       item_key_by_coord(coord, key);
+       set_key_offset(key, get_key_offset(reiser4_max_key()));
+       return key;
+}
+
+/* plugin->u.item.b.can_contain_key */
+int can_contain_key_tail(const coord_t *coord, const reiser4_key *key,
+                        const reiser4_item_data *data)
+{
+       reiser4_key item_key;
+
+       if (item_plugin_by_coord(coord) != data->iplug)
+               return 0;
+
+       item_key_by_coord(coord, &item_key);
+       if (get_key_locality(key) != get_key_locality(&item_key) ||
+           get_key_objectid(key) != get_key_objectid(&item_key))
+               return 0;
+
+       return 1;
+}
+
+/* plugin->u.item.b.mergeable
+   first item is of tail type */
+/* Audited by: green(2002.06.14) */
+int mergeable_tail(const coord_t *p1, const coord_t *p2)
+{
+       reiser4_key key1, key2;
+
+       assert("vs-535", plugin_of_group(item_plugin_by_coord(p1),
+                                        UNIX_FILE_METADATA_ITEM_TYPE));
+       assert("vs-365", item_id_by_coord(p1) == FORMATTING_ID);
+
+       if (item_id_by_coord(p2) != FORMATTING_ID) {
+               /* second item is of another type */
+               return 0;
+       }
+
+       item_key_by_coord(p1, &key1);
+       item_key_by_coord(p2, &key2);
+       if (get_key_locality(&key1) != get_key_locality(&key2) ||
+           get_key_objectid(&key1) != get_key_objectid(&key2)
+           || get_key_type(&key1) != get_key_type(&key2)) {
+               /* items of different objects */
+               return 0;
+       }
+       if (get_key_offset(&key1) + nr_units_tail(p1) != get_key_offset(&key2)) {
+               /* not adjacent items */
+               return 0;
+       }
+       return 1;
+}
+
+/* plugin->u.item.b.print
+   plugin->u.item.b.check */
+
+/* plugin->u.item.b.nr_units */
+pos_in_node_t nr_units_tail(const coord_t * coord)
+{
+       return item_length_by_coord(coord);
+}
+
+/* plugin->u.item.b.lookup */
+lookup_result
+lookup_tail(const reiser4_key * key, lookup_bias bias, coord_t * coord)
+{
+       reiser4_key item_key;
+       __u64 lookuped, offset;
+       unsigned nr_units;
+
+       item_key_by_coord(coord, &item_key);
+       offset = get_key_offset(item_key_by_coord(coord, &item_key));
+       nr_units = nr_units_tail(coord);
+
+       /* key we are looking for must be greater than key of item @coord */
+       assert("vs-416", keygt(key, &item_key));
+
+       /* offset we are looking for */
+       lookuped = get_key_offset(key);
+
+       if (lookuped >= offset && lookuped < offset + nr_units) {
+               /* byte we are looking for is in this item */
+               coord->unit_pos = lookuped - offset;
+               coord->between = AT_UNIT;
+               return CBK_COORD_FOUND;
+       }
+
+       /* set coord after last unit */
+       coord->unit_pos = nr_units - 1;
+       coord->between = AFTER_UNIT;
+       return bias ==
+           FIND_MAX_NOT_MORE_THAN ? CBK_COORD_FOUND : CBK_COORD_NOTFOUND;
+}
+
+/* plugin->u.item.b.paste */
+int
+paste_tail(coord_t *coord, reiser4_item_data *data,
+          carry_plugin_info *info UNUSED_ARG)
+{
+       unsigned old_item_length;
+       char *item;
+
+       /* length the item had before resizing has been performed */
+       old_item_length = item_length_by_coord(coord) - data->length;
+
+       /* tail items never get pasted in the middle */
+       assert("vs-363",
+              (coord->unit_pos == 0 && coord->between == BEFORE_UNIT) ||
+              (coord->unit_pos == old_item_length - 1 &&
+               coord->between == AFTER_UNIT) ||
+              (coord->unit_pos == 0 && old_item_length == 0
+               && coord->between == AT_UNIT));
+
+       item = item_body_by_coord(coord);
+       if (coord->unit_pos == 0)
+               /* make space for pasted data when pasting at the beginning of
+                  the item */
+               memmove(item + data->length, item, old_item_length);
+
+       if (coord->between == AFTER_UNIT)
+               coord->unit_pos++;
+
+       if (data->data) {
+               assert("vs-554", data->user == 0 || data->user == 1);
+               if (data->user) {
+                       assert("nikita-3035", reiser4_schedulable());
+                       /* copy from user space */
+                       if (__copy_from_user(item + coord->unit_pos,
+                                            (const char __user *)data->data,
+                                            (unsigned)data->length))
+                               return RETERR(-EFAULT);
+               } else
+                       /* copy from kernel space */
+                       memcpy(item + coord->unit_pos, data->data,
+                              (unsigned)data->length);
+       } else {
+               memset(item + coord->unit_pos, 0, (unsigned)data->length);
+       }
+       return 0;
+}
+
+/* plugin->u.item.b.fast_paste */
+
+/* plugin->u.item.b.can_shift
+   number of units is returned via return value, number of bytes via @size. For
+   tail items they coincide */
+int
+can_shift_tail(unsigned free_space, coord_t * source UNUSED_ARG,
+              znode * target UNUSED_ARG, shift_direction direction UNUSED_ARG,
+              unsigned *size, unsigned want)
+{
+       /* make sure that that we do not want to shift more than we have */
+       assert("vs-364", want > 0
+              && want <= (unsigned)item_length_by_coord(source));
+
+       *size = min(want, free_space);
+       return *size;
+}
+
+/* plugin->u.item.b.copy_units */
+void
+copy_units_tail(coord_t * target, coord_t * source,
+               unsigned from, unsigned count,
+               shift_direction where_is_free_space,
+               unsigned free_space UNUSED_ARG)
+{
+       /* make sure that item @target is expanded already */
+       assert("vs-366", (unsigned)item_length_by_coord(target) >= count);
+       assert("vs-370", free_space >= count);
+
+       if (where_is_free_space == SHIFT_LEFT) {
+               /* append item @target with @count first bytes of @source */
+               assert("vs-365", from == 0);
+
+               memcpy((char *)item_body_by_coord(target) +
+                      item_length_by_coord(target) - count,
+                      (char *)item_body_by_coord(source), count);
+       } else {
+               /* target item is moved to right already */
+               reiser4_key key;
+
+               assert("vs-367",
+                      (unsigned)item_length_by_coord(source) == from + count);
+
+               memcpy((char *)item_body_by_coord(target),
+                      (char *)item_body_by_coord(source) + from, count);
+
+               /* new units are inserted before first unit in an item,
+                  therefore, we have to update item key */
+               item_key_by_coord(source, &key);
+               set_key_offset(&key, get_key_offset(&key) + from);
+
+               node_plugin_by_node(target->node)->update_item_key(target, &key,
+                                                                  NULL /*info */);
+       }
+}
+
+/* plugin->u.item.b.create_hook */
+
+/* item_plugin->b.kill_hook
+   this is called when @count units starting from @from-th one are going to be removed
+   */
+int
+kill_hook_tail(const coord_t * coord, pos_in_node_t from,
+              pos_in_node_t count, struct carry_kill_data *kdata)
+{
+       reiser4_key key;
+       loff_t start, end;
+
+       assert("vs-1577", kdata);
+       assert("vs-1579", kdata->inode);
+
+       item_key_by_coord(coord, &key);
+       start = get_key_offset(&key) + from;
+       end = start + count;
+       fake_kill_hook_tail(kdata->inode, start, end, kdata->params.truncate);
+       return 0;
+}
+
+/* plugin->u.item.b.shift_hook */
+
+/* helper for kill_units_tail and cut_units_tail */
+static int
+do_cut_or_kill(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+              reiser4_key * smallest_removed, reiser4_key * new_first)
+{
+       pos_in_node_t count;
+
+       /* this method is only called to remove part of item */
+       assert("vs-374", (to - from + 1) < item_length_by_coord(coord));
+       /* tails items are never cut from the middle of an item */
+       assert("vs-396", ergo(from != 0, to == coord_last_unit_pos(coord)));
+       assert("vs-1558", ergo(from == 0, to < coord_last_unit_pos(coord)));
+
+       count = to - from + 1;
+
+       if (smallest_removed) {
+               /* store smallest key removed */
+               item_key_by_coord(coord, smallest_removed);
+               set_key_offset(smallest_removed,
+                              get_key_offset(smallest_removed) + from);
+       }
+       if (new_first) {
+               /* head of item is cut */
+               assert("vs-1529", from == 0);
+
+               item_key_by_coord(coord, new_first);
+               set_key_offset(new_first,
+                              get_key_offset(new_first) + from + count);
+       }
+
+       if (REISER4_DEBUG)
+               memset((char *)item_body_by_coord(coord) + from, 0, count);
+       return count;
+}
+
+/* plugin->u.item.b.cut_units */
+int
+cut_units_tail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+              struct carry_cut_data *cdata UNUSED_ARG,
+              reiser4_key * smallest_removed, reiser4_key * new_first)
+{
+       return do_cut_or_kill(coord, from, to, smallest_removed, new_first);
+}
+
+/* plugin->u.item.b.kill_units */
+int
+kill_units_tail(coord_t * coord, pos_in_node_t from, pos_in_node_t to,
+               struct carry_kill_data *kdata, reiser4_key * smallest_removed,
+               reiser4_key * new_first)
+{
+       kill_hook_tail(coord, from, to - from + 1, kdata);
+       return do_cut_or_kill(coord, from, to, smallest_removed, new_first);
+}
+
+/* plugin->u.item.b.unit_key */
+reiser4_key *unit_key_tail(const coord_t * coord, reiser4_key * key)
+{
+       assert("vs-375", coord_is_existing_unit(coord));
+
+       item_key_by_coord(coord, key);
+       set_key_offset(key, (get_key_offset(key) + coord->unit_pos));
+
+       return key;
+}
+
+/* plugin->u.item.b.estimate
+   plugin->u.item.b.item_data_by_flow */
+
+/* tail redpage function. It is called from readpage_tail(). */
+static int do_readpage_tail(uf_coord_t *uf_coord, struct page *page)
+{
+       tap_t tap;
+       int result;
+       coord_t coord;
+       lock_handle lh;
+       int count, mapped;
+       struct inode *inode;
+       char *pagedata;
+
+       /* saving passed coord in order to do not move it by tap. */
+       init_lh(&lh);
+       copy_lh(&lh, uf_coord->lh);
+       inode = page->mapping->host;
+       coord_dup(&coord, &uf_coord->coord);
+
+       reiser4_tap_init(&tap, &coord, &lh, ZNODE_READ_LOCK);
+
+       if ((result = reiser4_tap_load(&tap)))
+               goto out_tap_done;
+
+       /* lookup until page is filled up. */
+       for (mapped = 0; mapped < PAGE_CACHE_SIZE; ) {
+               /* number of bytes to be copied to page */
+               count = item_length_by_coord(&coord) - coord.unit_pos;
+               if (count > PAGE_CACHE_SIZE - mapped)
+                       count = PAGE_CACHE_SIZE - mapped;
+
+               /* attach @page to address space and get data address */
+               pagedata = kmap_atomic(page, KM_USER0);
+
+               /* copy tail item to page */
+               memcpy(pagedata + mapped,
+                      ((char *)item_body_by_coord(&coord) + coord.unit_pos),
+                      count);
+               mapped += count;
+
+               flush_dcache_page(page);
+
+               /* dettach page from address space */
+               kunmap_atomic(pagedata, KM_USER0);
+
+               /* Getting next tail item. */
+               if (mapped < PAGE_CACHE_SIZE) {
+                       /*
+                        * unlock page in order to avoid keep it locked
+                        * during tree lookup, which takes long term locks
+                        */
+                       unlock_page(page);
+
+                       /* getting right neighbour. */
+                       result = go_dir_el(&tap, RIGHT_SIDE, 0);
+
+                       /* lock page back */
+                       lock_page(page);
+                       if (PageUptodate(page)) {
+                               /*
+                                * another thread read the page, we have
+                                * nothing to do
+                                */
+                               result = 0;
+                               goto out_unlock_page;
+                       }
+
+                       if (result) {
+                               if (result == -E_NO_NEIGHBOR) {
+                                       /*
+                                        * rigth neighbor is not a formatted
+                                        * node
+                                        */
+                                       result = 0;
+                                       goto done;
+                               } else {
+                                       goto out_tap_relse;
+                               }
+                       } else {
+                               if (!inode_file_plugin(inode)->
+                                   owns_item(inode, &coord)) {
+                                       /* item of another file is found */
+                                       result = 0;
+                                       goto done;
+                               }
+                       }
+               }
+       }
+
+ done:
+       if (mapped != PAGE_CACHE_SIZE) {
+               pagedata = kmap_atomic(page, KM_USER0);
+               memset(pagedata + mapped, 0, PAGE_CACHE_SIZE - mapped);
+               flush_dcache_page(page);
+               kunmap_atomic(pagedata, KM_USER0);
+       }
+       SetPageUptodate(page);
+ out_unlock_page:
+       unlock_page(page);
+ out_tap_relse:
+       reiser4_tap_relse(&tap);
+ out_tap_done:
+       reiser4_tap_done(&tap);
+       return result;
+}
+
+/*
+   plugin->s.file.readpage
+   reiser4_read->unix_file_read->page_cache_readahead->reiser4_readpage->unix_file_readpage->readpage_tail
+   or
+   filemap_nopage->reiser4_readpage->readpage_unix_file->->readpage_tail
+
+   At the beginning: coord->node is read locked, zloaded, page is locked, coord is set to existing unit inside of tail
+   item. */
+int readpage_tail(void *vp, struct page *page)
+{
+       uf_coord_t *uf_coord = vp;
+       ON_DEBUG(coord_t * coord = &uf_coord->coord);
+       ON_DEBUG(reiser4_key key);
+
+       assert("umka-2515", PageLocked(page));
+       assert("umka-2516", !PageUptodate(page));
+       assert("umka-2517", !jprivate(page) && !PagePrivate(page));
+       assert("umka-2518", page->mapping && page->mapping->host);
+
+       assert("umka-2519", znode_is_loaded(coord->node));
+       assert("umka-2520", item_is_tail(coord));
+       assert("umka-2521", coord_is_existing_unit(coord));
+       assert("umka-2522", znode_is_rlocked(coord->node));
+       assert("umka-2523",
+              page->mapping->host->i_ino ==
+              get_key_objectid(item_key_by_coord(coord, &key)));
+
+       return do_readpage_tail(uf_coord, page);
+}
+
+/**
+ * overwrite_tail
+ * @flow:
+ * @coord:
+ *
+ * Overwrites tail item or its part by user data. Returns number of bytes
+ * written or error code.
+ */
+static int overwrite_tail(flow_t *flow, coord_t *coord)
+{
+       unsigned count;
+
+       assert("vs-570", flow->user == 1);
+       assert("vs-946", flow->data);
+       assert("vs-947", coord_is_existing_unit(coord));
+       assert("vs-948", znode_is_write_locked(coord->node));
+       assert("nikita-3036", reiser4_schedulable());
+
+       count = item_length_by_coord(coord) - coord->unit_pos;
+       if (count > flow->length)
+               count = flow->length;
+
+       if (__copy_from_user((char *)item_body_by_coord(coord) + coord->unit_pos,
+                            (const char __user *)flow->data, count))
+               return RETERR(-EFAULT);
+
+       znode_make_dirty(coord->node);
+       return count;
+}
+
+/**
+ * insert_first_tail
+ * @inode:
+ * @flow:
+ * @coord:
+ * @lh:
+ *
+ * Returns number of bytes written or error code.
+ */
+static ssize_t insert_first_tail(struct inode *inode, flow_t *flow,
+                                coord_t *coord, lock_handle *lh)
+{
+       int result;
+       loff_t to_write;
+       unix_file_info_t *uf_info;
+
+       if (get_key_offset(&flow->key) != 0) {
+               /*
+                * file is empty and we have to write not to the beginning of
+                * file. Create a hole at the beginning of file. On success
+                * insert_flow returns 0 as number of written bytes which is
+                * what we have to return on padding a file with holes
+                */
+               flow->data = NULL;
+               flow->length = get_key_offset(&flow->key);
+               set_key_offset(&flow->key, 0);
+               /*
+                * holes in files built of tails are stored just like if there
+                * were real data which are all zeros. Therefore we have to
+                * allocate quota here as well
+                */
+               if (DQUOT_ALLOC_SPACE_NODIRTY(inode, flow->length))
+                       return RETERR(-EDQUOT);
+               result = reiser4_insert_flow(coord, lh, flow);
+               if (flow->length)
+                       DQUOT_FREE_SPACE_NODIRTY(inode, flow->length);
+
+               uf_info = unix_file_inode_data(inode);
+
+               /*
+                * first item insertion is only possible when writing to empty
+                * file or performing tail conversion
+                */
+               assert("", (uf_info->container == UF_CONTAINER_EMPTY ||
+                           (reiser4_inode_get_flag(inode,
+                                                   REISER4_PART_MIXED) &&
+                            reiser4_inode_get_flag(inode,
+                                                   REISER4_PART_IN_CONV))));
+               /* if file was empty - update its state */
+               if (result == 0 && uf_info->container == UF_CONTAINER_EMPTY)
+                       uf_info->container = UF_CONTAINER_TAILS;
+               return result;
+       }
+
+       /* check quota before appending data */
+       if (DQUOT_ALLOC_SPACE_NODIRTY(inode, flow->length))
+               return RETERR(-EDQUOT);
+
+       to_write = flow->length;
+       result = reiser4_insert_flow(coord, lh, flow);
+       if (flow->length)
+               DQUOT_FREE_SPACE_NODIRTY(inode, flow->length);
+       return (to_write - flow->length) ? (to_write - flow->length) : result;
+}
+
+/**
+ * append_tail
+ * @inode:
+ * @flow:
+ * @coord:
+ * @lh:
+ *
+ * Returns number of bytes written or error code.
+ */
+static ssize_t append_tail(struct inode *inode,
+                          flow_t *flow, coord_t *coord, lock_handle *lh)
+{
+       int result;
+       reiser4_key append_key;
+       loff_t to_write;
+
+       if (!keyeq(&flow->key, append_key_tail(coord, &append_key))) {
+               flow->data = NULL;
+               flow->length = get_key_offset(&flow->key) - get_key_offset(&append_key);
+               set_key_offset(&flow->key, get_key_offset(&append_key));
+               /*
+                * holes in files built of tails are stored just like if there
+                * were real data which are all zeros. Therefore we have to
+                * allocate quota here as well
+                */
+               if (DQUOT_ALLOC_SPACE_NODIRTY(inode, flow->length))
+                       return RETERR(-EDQUOT);
+               result = reiser4_insert_flow(coord, lh, flow);
+               if (flow->length)
+                       DQUOT_FREE_SPACE_NODIRTY(inode, flow->length);
+               return result;
+       }
+
+       /* check quota before appending data */
+       if (DQUOT_ALLOC_SPACE_NODIRTY(inode, flow->length))
+               return RETERR(-EDQUOT);
+
+       to_write = flow->length;
+       result = reiser4_insert_flow(coord, lh, flow);
+       if (flow->length)
+               DQUOT_FREE_SPACE_NODIRTY(inode, flow->length);
+       return (to_write - flow->length) ? (to_write - flow->length) : result;
+}
+
+/**
+ * write_tail_reserve_space - reserve space for tail write operation
+ * @inode:
+ *
+ * Estimates and reserves space which may be required for writing one flow to a
+ * file
+ */
+static int write_extent_reserve_space(struct inode *inode)
+{
+       __u64 count;
+       reiser4_tree *tree;
+
+       /*
+        * to write one flow to a file by tails we have to reserve disk space for:
+
+        * 1. find_file_item may have to insert empty node to the tree (empty
+        * leaf node between two extent items). This requires 1 block and
+        * number of blocks which are necessary to perform insertion of an
+        * internal item into twig level.
+        *
+        * 2. flow insertion
+        *
+        * 3. stat data update
+        */
+       tree = reiser4_tree_by_inode(inode);
+       count = estimate_one_insert_item(tree) +
+               estimate_insert_flow(tree->height) +
+               estimate_one_insert_item(tree);
+       grab_space_enable();
+       return reiser4_grab_space(count, 0 /* flags */);
+}
+
+#define PAGE_PER_FLOW 4
+
+static loff_t faultin_user_pages(const char __user *buf, size_t count)
+{
+       loff_t faulted;
+       int to_fault;
+
+       if (count > PAGE_PER_FLOW * PAGE_CACHE_SIZE)
+               count = PAGE_PER_FLOW * PAGE_CACHE_SIZE;
+       faulted = 0;
+       while (count > 0) {
+               to_fault = PAGE_CACHE_SIZE;
+               if (count < to_fault)
+                       to_fault = count;
+               fault_in_pages_readable(buf + faulted, to_fault);
+               count -= to_fault;
+               faulted += to_fault;
+       }
+       return faulted;
+}
+
+/**
+ * reiser4_write_extent - write method of tail item plugin
+ * @file: file to write to
+ * @buf: address of user-space buffer
+ * @count: number of bytes to write
+ * @pos: position in file to write to
+ *
+ * Returns number of written bytes or error code.
+ */
+ssize_t reiser4_write_tail(struct file *file, const char __user *buf,
+                          size_t count, loff_t *pos)
+{
+       struct inode *inode;
+       struct hint hint;
+       int result;
+       flow_t flow;
+       coord_t *coord;
+       lock_handle *lh;
+       znode *loaded;
+
+       inode = file->f_dentry->d_inode;
+
+       if (write_extent_reserve_space(inode))
+               return RETERR(-ENOSPC);
+
+       result = load_file_hint(file, &hint);
+       BUG_ON(result != 0);
+
+       flow.length = faultin_user_pages(buf, count);
+       flow.user = 1;
+       memcpy(&flow.data, &buf, sizeof(buf));
+       flow.op = WRITE_OP;
+       key_by_inode_and_offset_common(inode, *pos, &flow.key);
+
+       result = find_file_item(&hint, &flow.key, ZNODE_WRITE_LOCK, inode);
+       if (IS_CBKERR(result))
+               return result;
+
+       coord = &hint.ext_coord.coord;
+       lh = hint.ext_coord.lh;
+
+       result = zload(coord->node);
+       BUG_ON(result != 0);
+       loaded = coord->node;
+
+       if (coord->between == AFTER_UNIT) {
+               /* append with data or hole */
+               result = append_tail(inode, &flow, coord, lh);
+       } else if (coord->between == AT_UNIT) {
+               /* overwrite */
+               result = overwrite_tail(&flow, coord);
+       } else {
+               /* no items of this file yet. insert data or hole */
+               result = insert_first_tail(inode, &flow, coord, lh);
+       }
+       zrelse(loaded);
+       if (result < 0) {
+               done_lh(lh);
+               return result;
+       }
+
+       /* seal and unlock znode */
+       hint.ext_coord.valid = 0;
+       if (hint.ext_coord.valid)
+               reiser4_set_hint(&hint, &flow.key, ZNODE_WRITE_LOCK);
+       else
+               reiser4_unset_hint(&hint);
+
+       save_file_hint(file, &hint);
+       return result;
+}
+
+#if REISER4_DEBUG
+
+static int
+coord_matches_key_tail(const coord_t * coord, const reiser4_key * key)
+{
+       reiser4_key item_key;
+
+       assert("vs-1356", coord_is_existing_unit(coord));
+       assert("vs-1354", keylt(key, append_key_tail(coord, &item_key)));
+       assert("vs-1355", keyge(key, item_key_by_coord(coord, &item_key)));
+       return get_key_offset(key) ==
+           get_key_offset(&item_key) + coord->unit_pos;
+
+}
+
+#endif
+
+/* plugin->u.item.s.file.read */
+int reiser4_read_tail(struct file *file UNUSED_ARG, flow_t *f, hint_t *hint)
+{
+       unsigned count;
+       int item_length;
+       coord_t *coord;
+       uf_coord_t *uf_coord;
+
+       uf_coord = &hint->ext_coord;
+       coord = &uf_coord->coord;
+
+       assert("vs-571", f->user == 1);
+       assert("vs-571", f->data);
+       assert("vs-967", coord && coord->node);
+       assert("vs-1117", znode_is_rlocked(coord->node));
+       assert("vs-1118", znode_is_loaded(coord->node));
+
+       assert("nikita-3037", reiser4_schedulable());
+       assert("vs-1357", coord_matches_key_tail(coord, &f->key));
+
+       /* calculate number of bytes to read off the item */
+       item_length = item_length_by_coord(coord);
+       count = item_length_by_coord(coord) - coord->unit_pos;
+       if (count > f->length)
+               count = f->length;
+
+       /* user page has to be brought in so that major page fault does not
+        * occur here when longtem lock is held */
+       if (__copy_to_user((char __user *)f->data,
+                          ((char *)item_body_by_coord(coord) + coord->unit_pos),
+                          count))
+               return RETERR(-EFAULT);
+
+       /* probably mark_page_accessed() should only be called if
+        * coord->unit_pos is zero. */
+       mark_page_accessed(znode_page(coord->node));
+       move_flow_forward(f, count);
+
+       coord->unit_pos += count;
+       if (item_length == coord->unit_pos) {
+               coord->unit_pos--;
+               coord->between = AFTER_UNIT;
+       }
+
+       return 0;
+}
+
+/*
+   plugin->u.item.s.file.append_key
+   key of first byte which is the next to last byte by addressed by this item
+*/
+reiser4_key *append_key_tail(const coord_t * coord, reiser4_key * key)
+{
+       item_key_by_coord(coord, key);
+       set_key_offset(key, get_key_offset(key) + item_length_by_coord(coord));
+       return key;
+}
+
+/* plugin->u.item.s.file.init_coord_extension */
+void init_coord_extension_tail(uf_coord_t * uf_coord, loff_t lookuped)
+{
+       uf_coord->valid = 1;
+}
+
+/*
+  plugin->u.item.s.file.get_block
+*/
+int
+get_block_address_tail(const coord_t * coord, sector_t lblock, sector_t * block)
+{
+       assert("nikita-3252", znode_get_level(coord->node) == LEAF_LEVEL);
+
+       if (reiser4_blocknr_is_fake(znode_get_block(coord->node)))
+               /* if node has'nt obtainet its block number yet, return 0.
+                * Lets avoid upsetting users with some cosmic numbers beyond
+                * the device capacity.*/
+               *block = 0;
+       else
+               *block = *znode_get_block(coord->node);
+       return 0;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/item/tail.h linux-2.6.20/fs/reiser4/plugin/item/tail.h
--- linux-2.6.20.orig/fs/reiser4/plugin/item/tail.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/item/tail.h  2007-05-06 14:50:43.827015719 +0400
@@ -0,0 +1,58 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined( __REISER4_TAIL_H__ )
+#define __REISER4_TAIL_H__
+
+typedef struct {
+       int not_used;
+} tail_coord_extension_t;
+
+struct cut_list;
+
+/* plugin->u.item.b.* */
+reiser4_key *max_key_inside_tail(const coord_t *, reiser4_key *);
+int can_contain_key_tail(const coord_t * coord, const reiser4_key * key,
+                        const reiser4_item_data *);
+int mergeable_tail(const coord_t * p1, const coord_t * p2);
+pos_in_node_t nr_units_tail(const coord_t *);
+lookup_result lookup_tail(const reiser4_key *, lookup_bias, coord_t *);
+int paste_tail(coord_t *, reiser4_item_data *, carry_plugin_info *);
+int can_shift_tail(unsigned free_space, coord_t * source,
+                  znode * target, shift_direction, unsigned *size,
+                  unsigned want);
+void copy_units_tail(coord_t * target, coord_t * source, unsigned from,
+                    unsigned count, shift_direction, unsigned free_space);
+int kill_hook_tail(const coord_t *, pos_in_node_t from, pos_in_node_t count,
+                  struct carry_kill_data *);
+int cut_units_tail(coord_t *, pos_in_node_t from, pos_in_node_t to,
+                  struct carry_cut_data *, reiser4_key * smallest_removed,
+                  reiser4_key * new_first);
+int kill_units_tail(coord_t *, pos_in_node_t from, pos_in_node_t to,
+                   struct carry_kill_data *, reiser4_key * smallest_removed,
+                   reiser4_key * new_first);
+reiser4_key *unit_key_tail(const coord_t *, reiser4_key *);
+
+/* plugin->u.item.s.* */
+ssize_t reiser4_write_tail(struct file *file, const char __user *buf,
+                          size_t count, loff_t *pos);
+int reiser4_read_tail(struct file *, flow_t *, hint_t *);
+int readpage_tail(void *vp, struct page *page);
+reiser4_key *append_key_tail(const coord_t *, reiser4_key *);
+void init_coord_extension_tail(uf_coord_t *, loff_t offset);
+int get_block_address_tail(const coord_t *, sector_t, sector_t *);
+int item_balance_dirty_pages(struct address_space *, const flow_t *,
+                            hint_t *, int back_to_dirty, int set_hint);
+
+/* __REISER4_TAIL_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/Makefile linux-2.6.20/fs/reiser4/plugin/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/Makefile        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/Makefile     2007-05-06 14:50:43.827015719 +0400
@@ -0,0 +1,26 @@
+obj-$(CONFIG_REISER4_FS) += plugins.o
+
+plugins-objs :=                        \
+       plugin.o                \
+       plugin_set.o            \
+       object.o                \
+       inode_ops.o             \
+       inode_ops_rename.o      \
+       file_ops.o              \
+       file_ops_readdir.o      \
+       file_plugin_common.o    \
+       dir_plugin_common.o     \
+       digest.o                \
+       hash.o                  \
+       fibration.o             \
+       tail_policy.o           \
+       regular.o
+
+obj-$(CONFIG_REISER4_FS) += item/
+obj-$(CONFIG_REISER4_FS) += file/
+obj-$(CONFIG_REISER4_FS) += dir/
+obj-$(CONFIG_REISER4_FS) += node/
+obj-$(CONFIG_REISER4_FS) += compress/
+obj-$(CONFIG_REISER4_FS) += space/
+obj-$(CONFIG_REISER4_FS) += disk_format/
+obj-$(CONFIG_REISER4_FS) += security/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/node/Makefile linux-2.6.20/fs/reiser4/plugin/node/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/node/Makefile   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/node/Makefile        2007-05-06 14:50:43.827015719 +0400
@@ -0,0 +1,5 @@
+obj-$(CONFIG_REISER4_FS) += node_plugins.o
+
+node_plugins-objs :=   \
+       node.o          \
+       node40.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/node/node40.c linux-2.6.20/fs/reiser4/plugin/node/node40.c
--- linux-2.6.20.orig/fs/reiser4/plugin/node/node40.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/node/node40.c        2007-05-06 14:50:43.831016969 +0400
@@ -0,0 +1,2924 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../debug.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "../plugin_header.h"
+#include "../item/item.h"
+#include "node.h"
+#include "node40.h"
+#include "../plugin.h"
+#include "../../jnode.h"
+#include "../../znode.h"
+#include "../../pool.h"
+#include "../../carry.h"
+#include "../../tap.h"
+#include "../../tree.h"
+#include "../../super.h"
+#include "../../reiser4.h"
+
+#include <asm/uaccess.h>
+#include <linux/types.h>
+#include <linux/prefetch.h>
+
+/* leaf 40 format:
+
+  [node header | item 0, item 1, .., item N-1 |  free space | item_head N-1, .. item_head 1, item head 0 ]
+   plugin_id (16)                                                key
+   free_space (16)                                               pluginid (16)
+   free_space_start (16)                                         offset (16)
+   level (8)
+   num_items (16)
+   magic (32)
+   flush_time (32)
+*/
+/* NIKITA-FIXME-HANS: I told you guys not less than 10 times to not call it r4fs.  Change to "ReIs". */
+/* magic number that is stored in ->magic field of node header */
+static const __u32 REISER4_NODE_MAGIC = 0x52344653;    /* (*(__u32 *)"R4FS"); */
+
+static int prepare_for_update(znode * left, znode * right,
+                             carry_plugin_info * info);
+
+/* header of node of reiser40 format is at the beginning of node */
+static inline node40_header *node40_node_header(const znode * node     /* node to
+                                                                        * query */ )
+{
+       assert("nikita-567", node != NULL);
+       assert("nikita-568", znode_page(node) != NULL);
+       assert("nikita-569", zdata(node) != NULL);
+       return (node40_header *) zdata(node);
+}
+
+/* functions to get/set fields of node40_header */
+#define nh40_get_magic(nh) le32_to_cpu(get_unaligned(&(nh)->magic))
+#define nh40_get_free_space(nh) le16_to_cpu(get_unaligned(&(nh)->free_space))
+#define nh40_get_free_space_start(nh) le16_to_cpu(get_unaligned(&(nh)->free_space_start))
+#define nh40_get_level(nh) get_unaligned(&(nh)->level)
+#define nh40_get_num_items(nh) le16_to_cpu(get_unaligned(&(nh)->nr_items))
+#define nh40_get_flush_id(nh) le64_to_cpu(get_unaligned(&(nh)->flush_id))
+
+#define nh40_set_magic(nh, value) put_unaligned(cpu_to_le32(value), &(nh)->magic)
+#define nh40_set_free_space(nh, value) put_unaligned(cpu_to_le16(value), &(nh)->free_space)
+#define nh40_set_free_space_start(nh, value) put_unaligned(cpu_to_le16(value), &(nh)->free_space_start)
+#define nh40_set_level(nh, value) put_unaligned(value, &(nh)->level)
+#define nh40_set_num_items(nh, value) put_unaligned(cpu_to_le16(value), &(nh)->nr_items)
+#define nh40_set_mkfs_id(nh, value) put_unaligned(cpu_to_le32(value), &(nh)->mkfs_id)
+
+/* plugin field of node header should be read/set by
+   plugin_by_disk_id/save_disk_plugin */
+
+/* array of item headers is at the end of node */
+static inline item_header40 *node40_ih_at(const znode * node, unsigned pos)
+{
+       return (item_header40 *) (zdata(node) + znode_size(node)) - pos - 1;
+}
+
+/* ( page_address( node -> pg ) + PAGE_CACHE_SIZE ) - pos - 1
+ */
+static inline item_header40 *node40_ih_at_coord(const coord_t * coord)
+{
+       return (item_header40 *) (zdata(coord->node) +
+                                 znode_size(coord->node)) - (coord->item_pos) -
+           1;
+}
+
+/* functions to get/set fields of item_header40 */
+#define ih40_get_offset(ih) le16_to_cpu(get_unaligned(&(ih)->offset))
+
+#define ih40_set_offset(ih, value) put_unaligned(cpu_to_le16(value), &(ih)->offset)
+
+/* plugin field of item header should be read/set by
+   plugin_by_disk_id/save_disk_plugin */
+
+/* plugin methods */
+
+/* plugin->u.node.item_overhead
+   look for description of this method in plugin/node/node.h */
+size_t
+item_overhead_node40(const znode * node UNUSED_ARG, flow_t * f UNUSED_ARG)
+{
+       return sizeof(item_header40);
+}
+
+/* plugin->u.node.free_space
+   look for description of this method in plugin/node/node.h */
+size_t free_space_node40(znode * node)
+{
+       assert("nikita-577", node != NULL);
+       assert("nikita-578", znode_is_loaded(node));
+       assert("nikita-579", zdata(node) != NULL);
+
+       return nh40_get_free_space(node40_node_header(node));
+}
+
+/* private inline version of node40_num_of_items() for use in this file. This
+   is necessary, because address of node40_num_of_items() is taken and it is
+   never inlined as a result. */
+static inline short node40_num_of_items_internal(const znode * node)
+{
+       return nh40_get_num_items(node40_node_header(node));
+}
+
+#if REISER4_DEBUG
+static inline void check_num_items(const znode * node)
+{
+       assert("nikita-2749",
+              node40_num_of_items_internal(node) == node->nr_items);
+       assert("nikita-2746", znode_is_write_locked(node));
+}
+#else
+#define check_num_items(node) noop
+#endif
+
+/* plugin->u.node.num_of_items
+   look for description of this method in plugin/node/node.h */
+int num_of_items_node40(const znode * node)
+{
+       return node40_num_of_items_internal(node);
+}
+
+static void
+node40_set_num_items(znode * node, node40_header * nh, unsigned value)
+{
+       assert("nikita-2751", node != NULL);
+       assert("nikita-2750", nh == node40_node_header(node));
+
+       check_num_items(node);
+       nh40_set_num_items(nh, value);
+       node->nr_items = value;
+       check_num_items(node);
+}
+
+/* plugin->u.node.item_by_coord
+   look for description of this method in plugin/node/node.h */
+char *item_by_coord_node40(const coord_t * coord)
+{
+       item_header40 *ih;
+       char *p;
+
+       /* @coord is set to existing item */
+       assert("nikita-596", coord != NULL);
+       assert("vs-255", coord_is_existing_item(coord));
+
+       ih = node40_ih_at_coord(coord);
+       p = zdata(coord->node) + ih40_get_offset(ih);
+       return p;
+}
+
+/* plugin->u.node.length_by_coord
+   look for description of this method in plugin/node/node.h */
+int length_by_coord_node40(const coord_t * coord)
+{
+       item_header40 *ih;
+       int result;
+
+       /* @coord is set to existing item */
+       assert("vs-256", coord != NULL);
+       assert("vs-257", coord_is_existing_item(coord));
+
+       ih = node40_ih_at_coord(coord);
+       if ((int)coord->item_pos ==
+           node40_num_of_items_internal(coord->node) - 1)
+               result =
+                   nh40_get_free_space_start(node40_node_header(coord->node)) -
+                   ih40_get_offset(ih);
+       else
+               result = ih40_get_offset(ih - 1) - ih40_get_offset(ih);
+
+       return result;
+}
+
+static pos_in_node_t
+node40_item_length(const znode * node, pos_in_node_t item_pos)
+{
+       item_header40 *ih;
+       pos_in_node_t result;
+
+       /* @coord is set to existing item */
+       assert("vs-256", node != NULL);
+       assert("vs-257", node40_num_of_items_internal(node) > item_pos);
+
+       ih = node40_ih_at(node, item_pos);
+       if (item_pos == node40_num_of_items_internal(node) - 1)
+               result =
+                   nh40_get_free_space_start(node40_node_header(node)) -
+                   ih40_get_offset(ih);
+       else
+               result = ih40_get_offset(ih - 1) - ih40_get_offset(ih);
+
+       return result;
+}
+
+/* plugin->u.node.plugin_by_coord
+   look for description of this method in plugin/node/node.h */
+item_plugin *plugin_by_coord_node40(const coord_t * coord)
+{
+       item_header40 *ih;
+       item_plugin *result;
+
+       /* @coord is set to existing item */
+       assert("vs-258", coord != NULL);
+       assert("vs-259", coord_is_existing_item(coord));
+
+       ih = node40_ih_at_coord(coord);
+       /* pass NULL in stead of current tree. This is time critical call. */
+       result = item_plugin_by_disk_id(NULL, &ih->plugin_id);
+       return result;
+}
+
+/* plugin->u.node.key_at
+   look for description of this method in plugin/node/node.h */
+reiser4_key *key_at_node40(const coord_t * coord, reiser4_key * key)
+{
+       item_header40 *ih;
+
+       assert("nikita-1765", coord_is_existing_item(coord));
+
+       /* @coord is set to existing item */
+       ih = node40_ih_at_coord(coord);
+       memcpy(key, &ih->key, sizeof(reiser4_key));
+       return key;
+}
+
+/* VS-FIXME-HANS: please review whether the below are properly disabled when debugging is disabled */
+
+#define NODE_INCSTAT(n, counter)                                               \
+       reiser4_stat_inc_at_level(znode_get_level(n), node.lookup.counter)
+
+#define NODE_ADDSTAT(n, counter, val)                                          \
+       reiser4_stat_add_at_level(znode_get_level(n), node.lookup.counter, val)
+
+/* plugin->u.node.lookup
+   look for description of this method in plugin/node/node.h */
+node_search_result lookup_node40(znode * node /* node to query */ ,
+                                const reiser4_key * key /* key to look for */ ,
+                                lookup_bias bias /* search bias */ ,
+                                coord_t * coord /* resulting coord */ )
+{
+       int left;
+       int right;
+       int found;
+       int items;
+
+       item_header40 *lefth;
+       item_header40 *righth;
+
+       item_plugin *iplug;
+       item_header40 *bstop;
+       item_header40 *ih;
+       cmp_t order;
+
+       assert("nikita-583", node != NULL);
+       assert("nikita-584", key != NULL);
+       assert("nikita-585", coord != NULL);
+       assert("nikita-2693", znode_is_any_locked(node));
+       cassert(REISER4_SEQ_SEARCH_BREAK > 2);
+
+       items = node_num_items(node);
+
+       if (unlikely(items == 0)) {
+               coord_init_first_unit(coord, node);
+               return NS_NOT_FOUND;
+       }
+
+       /* binary search for item that can contain given key */
+       left = 0;
+       right = items - 1;
+       coord->node = node;
+       coord_clear_iplug(coord);
+       found = 0;
+
+       lefth = node40_ih_at(node, left);
+       righth = node40_ih_at(node, right);
+
+       /* It is known that for small arrays sequential search is on average
+          more efficient than binary. This is because sequential search is
+          coded as tight loop that can be better optimized by compilers and
+          for small array size gain from this optimization makes sequential
+          search the winner. Another, maybe more important, reason for this,
+          is that sequential array is more CPU cache friendly, whereas binary
+          search effectively destroys CPU caching.
+
+          Critical here is the notion of "smallness". Reasonable value of
+          REISER4_SEQ_SEARCH_BREAK can be found by playing with code in
+          fs/reiser4/ulevel/ulevel.c:test_search().
+
+          Don't try to further optimize sequential search by scanning from
+          right to left in attempt to use more efficient loop termination
+          condition (comparison with 0). This doesn't work.
+
+        */
+
+       while (right - left >= REISER4_SEQ_SEARCH_BREAK) {
+               int median;
+               item_header40 *medianh;
+
+               median = (left + right) / 2;
+               medianh = node40_ih_at(node, median);
+
+               assert("nikita-1084", median >= 0);
+               assert("nikita-1085", median < items);
+               switch (keycmp(key, &medianh->key)) {
+               case LESS_THAN:
+                       right = median;
+                       righth = medianh;
+                       break;
+               default:
+                       wrong_return_value("nikita-586", "keycmp");
+               case GREATER_THAN:
+                       left = median;
+                       lefth = medianh;
+                       break;
+               case EQUAL_TO:
+                       do {
+                               --median;
+                               /* headers are ordered from right to left */
+                               ++medianh;
+                       } while (median >= 0 && keyeq(key, &medianh->key));
+                       right = left = median + 1;
+                       ih = lefth = righth = medianh - 1;
+                       found = 1;
+                       break;
+               }
+       }
+       /* sequential scan. Item headers, and, therefore, keys are stored at
+          the rightmost part of a node from right to left. We are trying to
+          access memory from left to right, and hence, scan in _descending_
+          order of item numbers.
+        */
+       if (!found) {
+               for (left = right, ih = righth; left >= 0; ++ih, --left) {
+                       cmp_t comparison;
+
+                       prefetchkey(&(ih + 1)->key);
+                       comparison = keycmp(&ih->key, key);
+                       if (comparison == GREATER_THAN)
+                               continue;
+                       if (comparison == EQUAL_TO) {
+                               found = 1;
+                               do {
+                                       --left;
+                                       ++ih;
+                               } while (left >= 0 && keyeq(&ih->key, key));
+                               ++left;
+                               --ih;
+                       } else {
+                               assert("nikita-1256", comparison == LESS_THAN);
+                       }
+                       break;
+               }
+               if (unlikely(left < 0))
+                       left = 0;
+       }
+
+       assert("nikita-3212", right >= left);
+       assert("nikita-3214",
+              equi(found, keyeq(&node40_ih_at(node, left)->key, key)));
+
+       coord_set_item_pos(coord, left);
+       coord->unit_pos = 0;
+       coord->between = AT_UNIT;
+
+       /* key < leftmost key in a mode or node is corrupted and keys
+          are not sorted  */
+       bstop = node40_ih_at(node, (unsigned)left);
+       order = keycmp(&bstop->key, key);
+       if (unlikely(order == GREATER_THAN)) {
+               if (unlikely(left != 0)) {
+                       /* screw up */
+                       warning("nikita-587", "Key less than %i key in a node",
+                               left);
+                       reiser4_print_key("key", key);
+                       reiser4_print_key("min", &bstop->key);
+                       print_coord_content("coord", coord);
+                       return RETERR(-EIO);
+               } else {
+                       coord->between = BEFORE_UNIT;
+                       return NS_NOT_FOUND;
+               }
+       }
+       /* left <= key, ok */
+       iplug = item_plugin_by_disk_id(znode_get_tree(node), &bstop->plugin_id);
+
+       if (unlikely(iplug == NULL)) {
+               warning("nikita-588", "Unknown plugin %i",
+                       le16_to_cpu(get_unaligned(&bstop->plugin_id)));
+               reiser4_print_key("key", key);
+               print_coord_content("coord", coord);
+               return RETERR(-EIO);
+       }
+
+       coord_set_iplug(coord, iplug);
+
+       /* if exact key from item header was found by binary search, no
+          further checks are necessary. */
+       if (found) {
+               assert("nikita-1259", order == EQUAL_TO);
+               return NS_FOUND;
+       }
+       if (iplug->b.max_key_inside != NULL) {
+               reiser4_key max_item_key;
+
+               /* key > max_item_key --- outside of an item */
+               if (keygt(key, iplug->b.max_key_inside(coord, &max_item_key))) {
+                       coord->unit_pos = 0;
+                       coord->between = AFTER_ITEM;
+                       /* FIXME-VS: key we are looking for does not fit into
+                          found item. Return NS_NOT_FOUND then. Without that
+                          the following case does not work: there is extent of
+                          file 10000, 10001. File 10000, 10002 has been just
+                          created. When writing to position 0 in that file -
+                          traverse_tree will stop here on twig level. When we
+                          want it to go down to leaf level
+                        */
+                       return NS_NOT_FOUND;
+               }
+       }
+
+       if (iplug->b.lookup != NULL) {
+               return iplug->b.lookup(key, bias, coord);
+       } else {
+               assert("nikita-1260", order == LESS_THAN);
+               coord->between = AFTER_UNIT;
+               return (bias == FIND_EXACT) ? NS_NOT_FOUND : NS_FOUND;
+       }
+}
+
+#undef NODE_ADDSTAT
+#undef NODE_INCSTAT
+
+/* plugin->u.node.estimate
+   look for description of this method in plugin/node/node.h */
+size_t estimate_node40(znode * node)
+{
+       size_t result;
+
+       assert("nikita-597", node != NULL);
+
+       result = free_space_node40(node) - sizeof(item_header40);
+
+       return (result > 0) ? result : 0;
+}
+
+/* plugin->u.node.check
+   look for description of this method in plugin/node/node.h */
+int check_node40(const znode * node /* node to check */ ,
+                __u32 flags /* check flags */ ,
+                const char **error /* where to store error message */ )
+{
+       int nr_items;
+       int i;
+       reiser4_key prev;
+       unsigned old_offset;
+       tree_level level;
+       coord_t coord;
+       int result;
+
+       assert("nikita-580", node != NULL);
+       assert("nikita-581", error != NULL);
+       assert("nikita-2948", znode_is_loaded(node));
+
+       if (ZF_ISSET(node, JNODE_HEARD_BANSHEE))
+               return 0;
+
+       assert("nikita-582", zdata(node) != NULL);
+
+       nr_items = node40_num_of_items_internal(node);
+       if (nr_items < 0) {
+               *error = "Negative number of items";
+               return -1;
+       }
+
+       if (flags & REISER4_NODE_DKEYS)
+               prev = *znode_get_ld_key((znode *) node);
+       else
+               prev = *reiser4_min_key();
+
+       old_offset = 0;
+       coord_init_zero(&coord);
+       coord.node = (znode *) node;
+       coord.unit_pos = 0;
+       coord.between = AT_UNIT;
+       level = znode_get_level(node);
+       for (i = 0; i < nr_items; i++) {
+               item_header40 *ih;
+               reiser4_key unit_key;
+               unsigned j;
+
+               ih = node40_ih_at(node, (unsigned)i);
+               coord_set_item_pos(&coord, i);
+               if ((ih40_get_offset(ih) >=
+                    znode_size(node) - nr_items * sizeof(item_header40)) ||
+                   (ih40_get_offset(ih) < sizeof(node40_header))) {
+                       *error = "Offset is out of bounds";
+                       return -1;
+               }
+               if (ih40_get_offset(ih) <= old_offset) {
+                       *error = "Offsets are in wrong order";
+                       return -1;
+               }
+               if ((i == 0) && (ih40_get_offset(ih) != sizeof(node40_header))) {
+                       *error = "Wrong offset of first item";
+                       return -1;
+               }
+               old_offset = ih40_get_offset(ih);
+
+               if (keygt(&prev, &ih->key)) {
+                       *error = "Keys are in wrong order";
+                       return -1;
+               }
+               if (!keyeq(&ih->key, unit_key_by_coord(&coord, &unit_key))) {
+                       *error = "Wrong key of first unit";
+                       return -1;
+               }
+               prev = ih->key;
+               for (j = 0; j < coord_num_units(&coord); ++j) {
+                       coord.unit_pos = j;
+                       unit_key_by_coord(&coord, &unit_key);
+                       if (keygt(&prev, &unit_key)) {
+                               *error = "Unit keys are in wrong order";
+                               return -1;
+                       }
+                       prev = unit_key;
+               }
+               coord.unit_pos = 0;
+               if (level != TWIG_LEVEL && item_is_extent(&coord)) {
+                       *error = "extent on the wrong level";
+                       return -1;
+               }
+               if (level == LEAF_LEVEL && item_is_internal(&coord)) {
+                       *error = "internal item on the wrong level";
+                       return -1;
+               }
+               if (level != LEAF_LEVEL &&
+                   !item_is_internal(&coord) && !item_is_extent(&coord)) {
+                       *error = "wrong item on the internal level";
+                       return -1;
+               }
+               if (level > TWIG_LEVEL && !item_is_internal(&coord)) {
+                       *error = "non-internal item on the internal level";
+                       return -1;
+               }
+#if REISER4_DEBUG
+               if (item_plugin_by_coord(&coord)->b.check
+                   && item_plugin_by_coord(&coord)->b.check(&coord, error))
+                       return -1;
+#endif
+               if (i) {
+                       coord_t prev_coord;
+                       /* two neighboring items can not be mergeable */
+                       coord_dup(&prev_coord, &coord);
+                       coord_prev_item(&prev_coord);
+                       if (are_items_mergeable(&prev_coord, &coord)) {
+                               *error = "mergeable items in one node";
+                               return -1;
+                       }
+
+               }
+       }
+
+       if ((flags & REISER4_NODE_DKEYS) && !node_is_empty(node)) {
+               coord_t coord;
+               item_plugin *iplug;
+
+               coord_init_last_unit(&coord, node);
+               iplug = item_plugin_by_coord(&coord);
+               if ((item_is_extent(&coord) || item_is_tail(&coord)) &&
+                   iplug->s.file.append_key != NULL) {
+                       reiser4_key mkey;
+
+                       iplug->s.file.append_key(&coord, &mkey);
+                       set_key_offset(&mkey, get_key_offset(&mkey) - 1);
+                       read_lock_dk(current_tree);
+                       result = keygt(&mkey, znode_get_rd_key((znode *) node));
+                       read_unlock_dk(current_tree);
+                       if (result) {
+                               *error = "key of rightmost item is too large";
+                               return -1;
+                       }
+               }
+       }
+       if (flags & REISER4_NODE_DKEYS) {
+               read_lock_tree(current_tree);
+               read_lock_dk(current_tree);
+
+               flags |= REISER4_NODE_TREE_STABLE;
+
+               if (keygt(&prev, znode_get_rd_key((znode *) node))) {
+                       if (flags & REISER4_NODE_TREE_STABLE) {
+                               *error = "Last key is greater than rdkey";
+                               read_unlock_dk(current_tree);
+                               read_unlock_tree(current_tree);
+                               return -1;
+                       }
+               }
+               if (keygt
+                   (znode_get_ld_key((znode *) node),
+                    znode_get_rd_key((znode *) node))) {
+                       *error = "ldkey is greater than rdkey";
+                       read_unlock_dk(current_tree);
+                       read_unlock_tree(current_tree);
+                       return -1;
+               }
+               if (ZF_ISSET(node, JNODE_LEFT_CONNECTED) &&
+                   (node->left != NULL) &&
+                   !ZF_ISSET(node->left, JNODE_HEARD_BANSHEE) &&
+                   ergo(flags & REISER4_NODE_TREE_STABLE,
+                        !keyeq(znode_get_rd_key(node->left),
+                               znode_get_ld_key((znode *) node)))
+                   && ergo(!(flags & REISER4_NODE_TREE_STABLE),
+                           keygt(znode_get_rd_key(node->left),
+                                 znode_get_ld_key((znode *) node)))) {
+                       *error = "left rdkey or ldkey is wrong";
+                       read_unlock_dk(current_tree);
+                       read_unlock_tree(current_tree);
+                       return -1;
+               }
+               if (ZF_ISSET(node, JNODE_RIGHT_CONNECTED) &&
+                   (node->right != NULL) &&
+                   !ZF_ISSET(node->right, JNODE_HEARD_BANSHEE) &&
+                   ergo(flags & REISER4_NODE_TREE_STABLE,
+                        !keyeq(znode_get_rd_key((znode *) node),
+                               znode_get_ld_key(node->right)))
+                   && ergo(!(flags & REISER4_NODE_TREE_STABLE),
+                           keygt(znode_get_rd_key((znode *) node),
+                                 znode_get_ld_key(node->right)))) {
+                       *error = "rdkey or right ldkey is wrong";
+                       read_unlock_dk(current_tree);
+                       read_unlock_tree(current_tree);
+                       return -1;
+               }
+
+               read_unlock_dk(current_tree);
+               read_unlock_tree(current_tree);
+       }
+
+       return 0;
+}
+
+/* plugin->u.node.parse
+   look for description of this method in plugin/node/node.h */
+int parse_node40(znode * node /* node to parse */ )
+{
+       node40_header *header;
+       int result;
+       d8 level;
+
+       header = node40_node_header((znode *) node);
+       result = -EIO;
+       level = nh40_get_level(header);
+       if (unlikely(((__u8) znode_get_level(node)) != level))
+               warning("nikita-494", "Wrong level found in node: %i != %i",
+                       znode_get_level(node), level);
+       else if (unlikely(nh40_get_magic(header) != REISER4_NODE_MAGIC))
+               warning("nikita-495",
+                       "Wrong magic in tree node: want %x, got %x",
+                       REISER4_NODE_MAGIC, nh40_get_magic(header));
+       else {
+               node->nr_items = node40_num_of_items_internal(node);
+               result = 0;
+       }
+       return RETERR(result);
+}
+
+/* plugin->u.node.init
+   look for description of this method in plugin/node/node.h */
+int init_node40(znode * node /* node to initialise */ )
+{
+       node40_header *header;
+
+       assert("nikita-570", node != NULL);
+       assert("nikita-572", zdata(node) != NULL);
+
+       header = node40_node_header(node);
+       memset(header, 0, sizeof(node40_header));
+       nh40_set_free_space(header, znode_size(node) - sizeof(node40_header));
+       nh40_set_free_space_start(header, sizeof(node40_header));
+       /* sane hypothesis: 0 in CPU format is 0 in disk format */
+       /* items: 0 */
+       save_plugin_id(node_plugin_to_plugin(node->nplug),
+                      &header->common_header.plugin_id);
+       nh40_set_level(header, znode_get_level(node));
+       nh40_set_magic(header, REISER4_NODE_MAGIC);
+       node->nr_items = 0;
+       nh40_set_mkfs_id(header, reiser4_mkfs_id(reiser4_get_current_sb()));
+
+       /* flags: 0 */
+       return 0;
+}
+
+#ifdef GUESS_EXISTS
+int guess_node40(const znode * node /* node to guess plugin of */ )
+{
+       node40_header *nethack;
+
+       assert("nikita-1058", node != NULL);
+       nethack = node40_node_header(node);
+       return
+           (nh40_get_magic(nethack) == REISER4_NODE_MAGIC) &&
+           (plugin_by_disk_id(znode_get_tree(node),
+                              REISER4_NODE_PLUGIN_TYPE,
+                              &nethack->common_header.plugin_id)->h.id ==
+            NODE40_ID);
+}
+#endif
+
+/* plugin->u.node.chage_item_size
+   look for description of this method in plugin/node/node.h */
+void change_item_size_node40(coord_t * coord, int by)
+{
+       node40_header *nh;
+       item_header40 *ih;
+       char *item_data;
+       int item_length;
+       unsigned i;
+
+       /* make sure that @item is coord of existing item */
+       assert("vs-210", coord_is_existing_item(coord));
+
+       nh = node40_node_header(coord->node);
+
+       item_data = item_by_coord_node40(coord);
+       item_length = length_by_coord_node40(coord);
+
+       /* move item bodies */
+       ih = node40_ih_at_coord(coord);
+       memmove(item_data + item_length + by, item_data + item_length,
+               nh40_get_free_space_start(node40_node_header(coord->node)) -
+               (ih40_get_offset(ih) + item_length));
+
+       /* update offsets of moved items */
+       for (i = coord->item_pos + 1; i < nh40_get_num_items(nh); i++) {
+               ih = node40_ih_at(coord->node, i);
+               ih40_set_offset(ih, ih40_get_offset(ih) + by);
+       }
+
+       /* update node header */
+       nh40_set_free_space(nh, nh40_get_free_space(nh) - by);
+       nh40_set_free_space_start(nh, nh40_get_free_space_start(nh) + by);
+}
+
+static int should_notify_parent(const znode * node)
+{
+       /* FIXME_JMACD This looks equivalent to znode_is_root(), right? -josh */
+       return !disk_addr_eq(znode_get_block(node),
+                            &znode_get_tree(node)->root_block);
+}
+
+/* plugin->u.node.create_item
+   look for description of this method in plugin/node/node.h */
+int
+create_item_node40(coord_t *target, const reiser4_key *key,
+                  reiser4_item_data *data, carry_plugin_info *info)
+{
+       node40_header *nh;
+       item_header40 *ih;
+       unsigned offset;
+       unsigned i;
+
+       nh = node40_node_header(target->node);
+
+       assert("vs-212", coord_is_between_items(target));
+       /* node must have enough free space */
+       assert("vs-254",
+              free_space_node40(target->node) >=
+              data->length + sizeof(item_header40));
+       assert("vs-1410", data->length >= 0);
+
+       if (coord_set_to_right(target))
+               /* there are not items to the right of @target, so, new item
+                  will be inserted after last one */
+               coord_set_item_pos(target, nh40_get_num_items(nh));
+
+       if (target->item_pos < nh40_get_num_items(nh)) {
+               /* there are items to be moved to prepare space for new
+                  item */
+               ih = node40_ih_at_coord(target);
+               /* new item will start at this offset */
+               offset = ih40_get_offset(ih);
+
+               memmove(zdata(target->node) + offset + data->length,
+                       zdata(target->node) + offset,
+                       nh40_get_free_space_start(nh) - offset);
+               /* update headers of moved items */
+               for (i = target->item_pos; i < nh40_get_num_items(nh); i++) {
+                       ih = node40_ih_at(target->node, i);
+                       ih40_set_offset(ih, ih40_get_offset(ih) + data->length);
+               }
+
+               /* @ih is set to item header of the last item, move item headers */
+               memmove(ih - 1, ih,
+                       sizeof(item_header40) * (nh40_get_num_items(nh) -
+                                                target->item_pos));
+       } else {
+               /* new item will start at this offset */
+               offset = nh40_get_free_space_start(nh);
+       }
+
+       /* make item header for the new item */
+       ih = node40_ih_at_coord(target);
+       memcpy(&ih->key, key, sizeof(reiser4_key));
+       ih40_set_offset(ih, offset);
+       save_plugin_id(item_plugin_to_plugin(data->iplug), &ih->plugin_id);
+
+       /* update node header */
+       nh40_set_free_space(nh,
+                           nh40_get_free_space(nh) - data->length -
+                           sizeof(item_header40));
+       nh40_set_free_space_start(nh,
+                                 nh40_get_free_space_start(nh) + data->length);
+       node40_set_num_items(target->node, nh, nh40_get_num_items(nh) + 1);
+
+       /* FIXME: check how does create_item work when between is set to BEFORE_UNIT */
+       target->unit_pos = 0;
+       target->between = AT_UNIT;
+       coord_clear_iplug(target);
+
+       /* initialize item */
+       if (data->iplug->b.init != NULL) {
+               data->iplug->b.init(target, NULL, data);
+       }
+       /* copy item body */
+       if (data->iplug->b.paste != NULL) {
+               data->iplug->b.paste(target, data, info);
+       } else if (data->data != NULL) {
+               if (data->user) {
+                       /* AUDIT: Are we really should not check that pointer
+                          from userspace was valid and data bytes were
+                          available? How will we return -EFAULT of some kind
+                          without this check? */
+                       assert("nikita-3038", reiser4_schedulable());
+                       /* copy data from user space */
+                       __copy_from_user(zdata(target->node) + offset,
+                                        (const char __user *)data->data,
+                                        (unsigned)data->length);
+               } else
+                       /* copy from kernel space */
+                       memcpy(zdata(target->node) + offset, data->data,
+                              (unsigned)data->length);
+       }
+
+       if (target->item_pos == 0) {
+               /* left delimiting key has to be updated */
+               prepare_for_update(NULL, target->node, info);
+       }
+
+       if (item_plugin_by_coord(target)->b.create_hook != NULL) {
+               item_plugin_by_coord(target)->b.create_hook(target, data->arg);
+       }
+
+       return 0;
+}
+
+/* plugin->u.node.update_item_key
+   look for description of this method in plugin/node/node.h */
+void
+update_item_key_node40(coord_t * target, const reiser4_key * key,
+                      carry_plugin_info * info)
+{
+       item_header40 *ih;
+
+       ih = node40_ih_at_coord(target);
+       memcpy(&ih->key, key, sizeof(reiser4_key));
+
+       if (target->item_pos == 0) {
+               prepare_for_update(NULL, target->node, info);
+       }
+}
+
+/* this bits encode cut mode */
+#define CMODE_TAIL 1
+#define CMODE_WHOLE 2
+#define CMODE_HEAD 4
+
+struct cut40_info {
+       int mode;
+       pos_in_node_t tail_removed;     /* position of item which gets tail removed */
+       pos_in_node_t first_removed;    /* position of first the leftmost item among items removed completely */
+       pos_in_node_t removed_count;    /* number of items removed completely */
+       pos_in_node_t head_removed;     /* position of item which gets head removed */
+
+       pos_in_node_t freed_space_start;
+       pos_in_node_t freed_space_end;
+       pos_in_node_t first_moved;
+       pos_in_node_t head_removed_location;
+};
+
+static void init_cinfo(struct cut40_info *cinfo)
+{
+       cinfo->mode = 0;
+       cinfo->tail_removed = MAX_POS_IN_NODE;
+       cinfo->first_removed = MAX_POS_IN_NODE;
+       cinfo->removed_count = MAX_POS_IN_NODE;
+       cinfo->head_removed = MAX_POS_IN_NODE;
+       cinfo->freed_space_start = MAX_POS_IN_NODE;
+       cinfo->freed_space_end = MAX_POS_IN_NODE;
+       cinfo->first_moved = MAX_POS_IN_NODE;
+       cinfo->head_removed_location = MAX_POS_IN_NODE;
+}
+
+/* complete cut_node40/kill_node40 content by removing the gap created by */
+static void compact(znode * node, struct cut40_info *cinfo)
+{
+       node40_header *nh;
+       item_header40 *ih;
+       pos_in_node_t freed;
+       pos_in_node_t pos, nr_items;
+
+       assert("vs-1526", (cinfo->freed_space_start != MAX_POS_IN_NODE &&
+                          cinfo->freed_space_end != MAX_POS_IN_NODE &&
+                          cinfo->first_moved != MAX_POS_IN_NODE));
+       assert("vs-1523", cinfo->freed_space_end >= cinfo->freed_space_start);
+
+       nh = node40_node_header(node);
+       nr_items = nh40_get_num_items(nh);
+
+       /* remove gap made up by removal */
+       memmove(zdata(node) + cinfo->freed_space_start,
+               zdata(node) + cinfo->freed_space_end,
+               nh40_get_free_space_start(nh) - cinfo->freed_space_end);
+
+       /* update item headers of moved items - change their locations */
+       pos = cinfo->first_moved;
+       ih = node40_ih_at(node, pos);
+       if (cinfo->head_removed_location != MAX_POS_IN_NODE) {
+               assert("vs-1580", pos == cinfo->head_removed);
+               ih40_set_offset(ih, cinfo->head_removed_location);
+               pos++;
+               ih--;
+       }
+
+       freed = cinfo->freed_space_end - cinfo->freed_space_start;
+       for (; pos < nr_items; pos++, ih--) {
+               assert("vs-1581", ih == node40_ih_at(node, pos));
+               ih40_set_offset(ih, ih40_get_offset(ih) - freed);
+       }
+
+       /* free space start moved to right */
+       nh40_set_free_space_start(nh, nh40_get_free_space_start(nh) - freed);
+
+       if (cinfo->removed_count != MAX_POS_IN_NODE) {
+               /* number of items changed. Remove item headers of those items */
+               ih = node40_ih_at(node, nr_items - 1);
+               memmove(ih + cinfo->removed_count, ih,
+                       sizeof(item_header40) * (nr_items -
+                                                cinfo->removed_count -
+                                                cinfo->first_removed));
+               freed += sizeof(item_header40) * cinfo->removed_count;
+               node40_set_num_items(node, nh, nr_items - cinfo->removed_count);
+       }
+
+       /* total amount of free space increased */
+       nh40_set_free_space(nh, nh40_get_free_space(nh) + freed);
+}
+
+int shrink_item_node40(coord_t * coord, int delta)
+{
+       node40_header *nh;
+       item_header40 *ih;
+       pos_in_node_t pos;
+       pos_in_node_t nr_items;
+       char *end;
+       znode *node;
+       int off;
+
+       assert("nikita-3487", coord != NULL);
+       assert("nikita-3488", delta >= 0);
+
+       node = coord->node;
+       nh = node40_node_header(node);
+       nr_items = nh40_get_num_items(nh);
+
+       ih = node40_ih_at_coord(coord);
+       assert("nikita-3489", delta <= length_by_coord_node40(coord));
+       off = ih40_get_offset(ih) + length_by_coord_node40(coord);
+       end = zdata(node) + off;
+
+       /* remove gap made up by removal */
+       memmove(end - delta, end, nh40_get_free_space_start(nh) - off);
+
+       /* update item headers of moved items - change their locations */
+       pos = coord->item_pos + 1;
+       ih = node40_ih_at(node, pos);
+       for (; pos < nr_items; pos++, ih--) {
+               assert("nikita-3490", ih == node40_ih_at(node, pos));
+               ih40_set_offset(ih, ih40_get_offset(ih) - delta);
+       }
+
+       /* free space start moved to left */
+       nh40_set_free_space_start(nh, nh40_get_free_space_start(nh) - delta);
+       /* total amount of free space increased */
+       nh40_set_free_space(nh, nh40_get_free_space(nh) + delta);
+       /*
+        * This method does _not_ changes number of items. Hence, it cannot
+        * make node empty. Also it doesn't remove items at all, which means
+        * that no keys have to be updated either.
+        */
+       return 0;
+}
+
+/* this is used by cut_node40 and kill_node40. It analyses input parameters and calculates cut mode. There are 2 types
+   of cut. First is when a unit is removed from the middle of an item.  In this case this function returns 1. All the
+   rest fits into second case: 0 or 1 of items getting tail cut, 0 or more items removed completely and 0 or 1 item
+   getting head cut. Function returns 0 in this case */
+static int
+parse_cut(struct cut40_info *cinfo, const struct cut_kill_params *params)
+{
+       reiser4_key left_key, right_key;
+       reiser4_key min_from_key, max_to_key;
+       const reiser4_key *from_key, *to_key;
+
+       init_cinfo(cinfo);
+
+       /* calculate minimal key stored in first item of items to be cut (params->from) */
+       item_key_by_coord(params->from, &min_from_key);
+       /* and max key stored in last item of items to be cut (params->to) */
+       max_item_key_by_coord(params->to, &max_to_key);
+
+       /* if cut key range is not defined in input parameters - define it using cut coord range */
+       if (params->from_key == NULL) {
+               assert("vs-1513", params->to_key == NULL);
+               unit_key_by_coord(params->from, &left_key);
+               from_key = &left_key;
+               max_unit_key_by_coord(params->to, &right_key);
+               to_key = &right_key;
+       } else {
+               from_key = params->from_key;
+               to_key = params->to_key;
+       }
+
+       if (params->from->item_pos == params->to->item_pos) {
+               if (keylt(&min_from_key, from_key)
+                   && keylt(to_key, &max_to_key))
+                       return 1;
+
+               if (keygt(from_key, &min_from_key)) {
+                       /* tail of item is to be cut cut */
+                       cinfo->tail_removed = params->from->item_pos;
+                       cinfo->mode |= CMODE_TAIL;
+               } else if (keylt(to_key, &max_to_key)) {
+                       /* head of item is to be cut */
+                       cinfo->head_removed = params->from->item_pos;
+                       cinfo->mode |= CMODE_HEAD;
+               } else {
+                       /* item is removed completely */
+                       cinfo->first_removed = params->from->item_pos;
+                       cinfo->removed_count = 1;
+                       cinfo->mode |= CMODE_WHOLE;
+               }
+       } else {
+               cinfo->first_removed = params->from->item_pos + 1;
+               cinfo->removed_count =
+                   params->to->item_pos - params->from->item_pos - 1;
+
+               if (keygt(from_key, &min_from_key)) {
+                       /* first item is not cut completely */
+                       cinfo->tail_removed = params->from->item_pos;
+                       cinfo->mode |= CMODE_TAIL;
+               } else {
+                       cinfo->first_removed--;
+                       cinfo->removed_count++;
+               }
+               if (keylt(to_key, &max_to_key)) {
+                       /* last item is not cut completely */
+                       cinfo->head_removed = params->to->item_pos;
+                       cinfo->mode |= CMODE_HEAD;
+               } else {
+                       cinfo->removed_count++;
+               }
+               if (cinfo->removed_count)
+                       cinfo->mode |= CMODE_WHOLE;
+       }
+
+       return 0;
+}
+
+static void
+call_kill_hooks(znode * node, pos_in_node_t from, pos_in_node_t count,
+               carry_kill_data * kdata)
+{
+       coord_t coord;
+       item_plugin *iplug;
+       pos_in_node_t pos;
+
+       coord.node = node;
+       coord.unit_pos = 0;
+       coord.between = AT_UNIT;
+       for (pos = 0; pos < count; pos++) {
+               coord_set_item_pos(&coord, from + pos);
+               coord.unit_pos = 0;
+               coord.between = AT_UNIT;
+               iplug = item_plugin_by_coord(&coord);
+               if (iplug->b.kill_hook) {
+                       iplug->b.kill_hook(&coord, 0, coord_num_units(&coord),
+                                          kdata);
+               }
+       }
+}
+
+/* this is used to kill item partially */
+static pos_in_node_t
+kill_units(coord_t * coord, pos_in_node_t from, pos_in_node_t to, void *data,
+          reiser4_key * smallest_removed, reiser4_key * new_first_key)
+{
+       struct carry_kill_data *kdata;
+       item_plugin *iplug;
+
+       kdata = data;
+       iplug = item_plugin_by_coord(coord);
+
+       assert("vs-1524", iplug->b.kill_units);
+       return iplug->b.kill_units(coord, from, to, kdata, smallest_removed,
+                                  new_first_key);
+}
+
+/* call item plugin to cut tail of file */
+static pos_in_node_t
+kill_tail(coord_t * coord, void *data, reiser4_key * smallest_removed)
+{
+       struct carry_kill_data *kdata;
+       pos_in_node_t to;
+
+       kdata = data;
+       to = coord_last_unit_pos(coord);
+       return kill_units(coord, coord->unit_pos, to, kdata, smallest_removed,
+                         NULL);
+}
+
+/* call item plugin to cut head of item */
+static pos_in_node_t
+kill_head(coord_t * coord, void *data, reiser4_key * smallest_removed,
+         reiser4_key * new_first_key)
+{
+       return kill_units(coord, 0, coord->unit_pos, data, smallest_removed,
+                         new_first_key);
+}
+
+/* this is used to cut item partially */
+static pos_in_node_t
+cut_units(coord_t * coord, pos_in_node_t from, pos_in_node_t to, void *data,
+         reiser4_key * smallest_removed, reiser4_key * new_first_key)
+{
+       carry_cut_data *cdata;
+       item_plugin *iplug;
+
+       cdata = data;
+       iplug = item_plugin_by_coord(coord);
+       assert("vs-302", iplug->b.cut_units);
+       return iplug->b.cut_units(coord, from, to, cdata, smallest_removed,
+                                 new_first_key);
+}
+
+/* call item plugin to cut tail of file */
+static pos_in_node_t
+cut_tail(coord_t * coord, void *data, reiser4_key * smallest_removed)
+{
+       carry_cut_data *cdata;
+       pos_in_node_t to;
+
+       cdata = data;
+       to = coord_last_unit_pos(cdata->params.from);
+       return cut_units(coord, coord->unit_pos, to, data, smallest_removed, NULL);
+}
+
+/* call item plugin to cut head of item */
+static pos_in_node_t
+cut_head(coord_t * coord, void *data, reiser4_key * smallest_removed,
+        reiser4_key * new_first_key)
+{
+       return cut_units(coord, 0, coord->unit_pos, data, smallest_removed,
+                        new_first_key);
+}
+
+/* this returns 1 of key of first item changed, 0 - if it did not */
+static int
+prepare_for_compact(struct cut40_info *cinfo,
+                   const struct cut_kill_params *params, int is_cut,
+                   void *data, carry_plugin_info * info)
+{
+       znode *node;
+       item_header40 *ih;
+       pos_in_node_t freed;
+       pos_in_node_t item_pos;
+       coord_t coord;
+       reiser4_key new_first_key;
+       pos_in_node_t(*kill_units_f) (coord_t *, pos_in_node_t, pos_in_node_t,
+                                     void *, reiser4_key *, reiser4_key *);
+       pos_in_node_t(*kill_tail_f) (coord_t *, void *, reiser4_key *);
+       pos_in_node_t(*kill_head_f) (coord_t *, void *, reiser4_key *,
+                                    reiser4_key *);
+       int retval;
+
+       retval = 0;
+
+       node = params->from->node;
+
+       assert("vs-184", node == params->to->node);
+       assert("vs-312", !node_is_empty(node));
+       assert("vs-297",
+              coord_compare(params->from, params->to) != COORD_CMP_ON_RIGHT);
+
+       if (is_cut) {
+               kill_units_f = cut_units;
+               kill_tail_f = cut_tail;
+               kill_head_f = cut_head;
+       } else {
+               kill_units_f = kill_units;
+               kill_tail_f = kill_tail;
+               kill_head_f = kill_head;
+       }
+
+       if (parse_cut(cinfo, params) == 1) {
+               /* cut from the middle of item */
+               freed =
+                   kill_units_f(params->from, params->from->unit_pos,
+                                params->to->unit_pos, data,
+                                params->smallest_removed, NULL);
+
+               item_pos = params->from->item_pos;
+               ih = node40_ih_at(node, item_pos);
+               cinfo->freed_space_start =
+                   ih40_get_offset(ih) + node40_item_length(node,
+                                                            item_pos) - freed;
+               cinfo->freed_space_end = cinfo->freed_space_start + freed;
+               cinfo->first_moved = item_pos + 1;
+       } else {
+               assert("vs-1521", (cinfo->tail_removed != MAX_POS_IN_NODE ||
+                                  cinfo->first_removed != MAX_POS_IN_NODE ||
+                                  cinfo->head_removed != MAX_POS_IN_NODE));
+
+               switch (cinfo->mode) {
+               case CMODE_TAIL:
+                       /* one item gets cut partially from its end */
+                       assert("vs-1562",
+                              cinfo->tail_removed == params->from->item_pos);
+
+                       freed =
+                           kill_tail_f(params->from, data,
+                                       params->smallest_removed);
+
+                       item_pos = cinfo->tail_removed;
+                       ih = node40_ih_at(node, item_pos);
+                       cinfo->freed_space_start =
+                           ih40_get_offset(ih) + node40_item_length(node,
+                                                                    item_pos) -
+                           freed;
+                       cinfo->freed_space_end =
+                           cinfo->freed_space_start + freed;
+                       cinfo->first_moved = cinfo->tail_removed + 1;
+                       break;
+
+               case CMODE_WHOLE:
+                       /* one or more items get removed completely */
+                       assert("vs-1563",
+                              cinfo->first_removed == params->from->item_pos);
+                       assert("vs-1564", cinfo->removed_count > 0
+                              && cinfo->removed_count != MAX_POS_IN_NODE);
+
+                       /* call kill hook for all items removed completely */
+                       if (is_cut == 0)
+                               call_kill_hooks(node, cinfo->first_removed,
+                                               cinfo->removed_count, data);
+
+                       item_pos = cinfo->first_removed;
+                       ih = node40_ih_at(node, item_pos);
+
+                       if (params->smallest_removed)
+                               memcpy(params->smallest_removed, &ih->key,
+                                      sizeof(reiser4_key));
+
+                       cinfo->freed_space_start = ih40_get_offset(ih);
+
+                       item_pos += (cinfo->removed_count - 1);
+                       ih -= (cinfo->removed_count - 1);
+                       cinfo->freed_space_end =
+                           ih40_get_offset(ih) + node40_item_length(node,
+                                                                    item_pos);
+                       cinfo->first_moved = item_pos + 1;
+                       if (cinfo->first_removed == 0)
+                               /* key of first item of the node changes */
+                               retval = 1;
+                       break;
+
+               case CMODE_HEAD:
+                       /* one item gets cut partially from its head */
+                       assert("vs-1565",
+                              cinfo->head_removed == params->from->item_pos);
+
+                       freed =
+                           kill_head_f(params->to, data,
+                                       params->smallest_removed,
+                                       &new_first_key);
+
+                       item_pos = cinfo->head_removed;
+                       ih = node40_ih_at(node, item_pos);
+                       cinfo->freed_space_start = ih40_get_offset(ih);
+                       cinfo->freed_space_end = ih40_get_offset(ih) + freed;
+                       cinfo->first_moved = cinfo->head_removed + 1;
+
+                       /* item head is removed, therefore, item key changed */
+                       coord.node = node;
+                       coord_set_item_pos(&coord, item_pos);
+                       coord.unit_pos = 0;
+                       coord.between = AT_UNIT;
+                       update_item_key_node40(&coord, &new_first_key, NULL);
+                       if (item_pos == 0)
+                               /* key of first item of the node changes */
+                               retval = 1;
+                       break;
+
+               case CMODE_TAIL | CMODE_WHOLE:
+                       /* one item gets cut from its end and one or more items get removed completely */
+                       assert("vs-1566",
+                              cinfo->tail_removed == params->from->item_pos);
+                       assert("vs-1567",
+                              cinfo->first_removed == cinfo->tail_removed + 1);
+                       assert("vs-1564", cinfo->removed_count > 0
+                              && cinfo->removed_count != MAX_POS_IN_NODE);
+
+                       freed =
+                           kill_tail_f(params->from, data,
+                                       params->smallest_removed);
+
+                       item_pos = cinfo->tail_removed;
+                       ih = node40_ih_at(node, item_pos);
+                       cinfo->freed_space_start =
+                           ih40_get_offset(ih) + node40_item_length(node,
+                                                                    item_pos) -
+                           freed;
+
+                       /* call kill hook for all items removed completely */
+                       if (is_cut == 0)
+                               call_kill_hooks(node, cinfo->first_removed,
+                                               cinfo->removed_count, data);
+
+                       item_pos += cinfo->removed_count;
+                       ih -= cinfo->removed_count;
+                       cinfo->freed_space_end =
+                           ih40_get_offset(ih) + node40_item_length(node,
+                                                                    item_pos);
+                       cinfo->first_moved = item_pos + 1;
+                       break;
+
+               case CMODE_WHOLE | CMODE_HEAD:
+                       /* one or more items get removed completely and one item gets cut partially from its head */
+                       assert("vs-1568",
+                              cinfo->first_removed == params->from->item_pos);
+                       assert("vs-1564", cinfo->removed_count > 0
+                              && cinfo->removed_count != MAX_POS_IN_NODE);
+                       assert("vs-1569",
+                              cinfo->head_removed ==
+                              cinfo->first_removed + cinfo->removed_count);
+
+                       /* call kill hook for all items removed completely */
+                       if (is_cut == 0)
+                               call_kill_hooks(node, cinfo->first_removed,
+                                               cinfo->removed_count, data);
+
+                       item_pos = cinfo->first_removed;
+                       ih = node40_ih_at(node, item_pos);
+
+                       if (params->smallest_removed)
+                               memcpy(params->smallest_removed, &ih->key,
+                                      sizeof(reiser4_key));
+
+                       freed =
+                           kill_head_f(params->to, data, NULL, &new_first_key);
+
+                       cinfo->freed_space_start = ih40_get_offset(ih);
+
+                       ih = node40_ih_at(node, cinfo->head_removed);
+                       /* this is the most complex case. Item which got head removed and items which are to be moved
+                          intact change their location differently. */
+                       cinfo->freed_space_end = ih40_get_offset(ih) + freed;
+                       cinfo->first_moved = cinfo->head_removed;
+                       cinfo->head_removed_location = cinfo->freed_space_start;
+
+                       /* item head is removed, therefore, item key changed */
+                       coord.node = node;
+                       coord_set_item_pos(&coord, cinfo->head_removed);
+                       coord.unit_pos = 0;
+                       coord.between = AT_UNIT;
+                       update_item_key_node40(&coord, &new_first_key, NULL);
+
+                       assert("vs-1579", cinfo->first_removed == 0);
+                       /* key of first item of the node changes */
+                       retval = 1;
+                       break;
+
+               case CMODE_TAIL | CMODE_HEAD:
+                       /* one item get cut from its end and its neighbor gets cut from its tail */
+                       impossible("vs-1576", "this can not happen currently");
+                       break;
+
+               case CMODE_TAIL | CMODE_WHOLE | CMODE_HEAD:
+                       impossible("vs-1577", "this can not happen currently");
+                       break;
+               default:
+                       impossible("vs-1578", "unexpected cut mode");
+                       break;
+               }
+       }
+       return retval;
+}
+
+/* plugin->u.node.kill
+   return value is number of items removed completely */
+int kill_node40(struct carry_kill_data *kdata, carry_plugin_info * info)
+{
+       znode *node;
+       struct cut40_info cinfo;
+       int first_key_changed;
+
+       node = kdata->params.from->node;
+
+       first_key_changed =
+           prepare_for_compact(&cinfo, &kdata->params, 0 /* not cut */ , kdata,
+                               info);
+       compact(node, &cinfo);
+
+       if (info) {
+               /* it is not called by node40_shift, so we have to take care
+                  of changes on upper levels */
+               if (node_is_empty(node)
+                   && !(kdata->flags & DELETE_RETAIN_EMPTY))
+                       /* all contents of node is deleted */
+                       prepare_removal_node40(node, info);
+               else if (first_key_changed) {
+                       prepare_for_update(NULL, node, info);
+               }
+       }
+
+       coord_clear_iplug(kdata->params.from);
+       coord_clear_iplug(kdata->params.to);
+
+       znode_make_dirty(node);
+       return cinfo.removed_count == MAX_POS_IN_NODE ? 0 : cinfo.removed_count;
+}
+
+/* plugin->u.node.cut
+   return value is number of items removed completely */
+int cut_node40(struct carry_cut_data *cdata, carry_plugin_info * info)
+{
+       znode *node;
+       struct cut40_info cinfo;
+       int first_key_changed;
+
+       node = cdata->params.from->node;
+
+       first_key_changed =
+           prepare_for_compact(&cinfo, &cdata->params, 1 /* not cut */ , cdata,
+                               info);
+       compact(node, &cinfo);
+
+       if (info) {
+               /* it is not called by node40_shift, so we have to take care
+                  of changes on upper levels */
+               if (node_is_empty(node))
+                       /* all contents of node is deleted */
+                       prepare_removal_node40(node, info);
+               else if (first_key_changed) {
+                       prepare_for_update(NULL, node, info);
+               }
+       }
+
+       coord_clear_iplug(cdata->params.from);
+       coord_clear_iplug(cdata->params.to);
+
+       znode_make_dirty(node);
+       return cinfo.removed_count == MAX_POS_IN_NODE ? 0 : cinfo.removed_count;
+}
+
+/* this structure is used by shift method of node40 plugin */
+struct shift_params {
+       shift_direction pend;   /* when @pend == append - we are shifting to
+                                  left, when @pend == prepend - to right */
+       coord_t wish_stop;      /* when shifting to left this is last unit we
+                                  want shifted, when shifting to right - this
+                                  is set to unit we want to start shifting
+                                  from */
+       znode *target;
+       int everything;         /* it is set to 1 if everything we have to shift is
+                                  shifted, 0 - otherwise */
+
+       /* FIXME-VS: get rid of read_stop */
+
+       /* these are set by estimate_shift */
+       coord_t real_stop;      /* this will be set to last unit which will be
+                                  really shifted */
+
+       /* coordinate in source node before operation of unit which becomes
+          first after shift to left of last after shift to right */
+       union {
+               coord_t future_first;
+               coord_t future_last;
+       } u;
+
+       unsigned merging_units; /* number of units of first item which have to
+                                  be merged with last item of target node */
+       unsigned merging_bytes; /* number of bytes in those units */
+
+       unsigned entire;        /* items shifted in their entirety */
+       unsigned entire_bytes;  /* number of bytes in those items */
+
+       unsigned part_units;    /* number of units of partially copied item */
+       unsigned part_bytes;    /* number of bytes in those units */
+
+       unsigned shift_bytes;   /* total number of bytes in items shifted (item
+                                  headers not included) */
+
+};
+
+static int item_creation_overhead(coord_t *item)
+{
+       return node_plugin_by_coord(item)->item_overhead(item->node, NULL);
+}
+
+/* how many units are there in @source starting from source->unit_pos
+   but not further than @stop_coord */
+static int
+wanted_units(coord_t *source, coord_t *stop_coord, shift_direction pend)
+{
+       if (pend == SHIFT_LEFT) {
+               assert("vs-181", source->unit_pos == 0);
+       } else {
+               assert("vs-182",
+                      source->unit_pos == coord_last_unit_pos(source));
+       }
+
+       if (source->item_pos != stop_coord->item_pos) {
+               /* @source and @stop_coord are different items */
+               return coord_last_unit_pos(source) + 1;
+       }
+
+       if (pend == SHIFT_LEFT) {
+               return stop_coord->unit_pos + 1;
+       } else {
+               return source->unit_pos - stop_coord->unit_pos + 1;
+       }
+}
+
+/* this calculates what can be copied from @shift->wish_stop.node to
+   @shift->target */
+static void
+estimate_shift(struct shift_params *shift, const reiser4_context * ctx)
+{
+       unsigned target_free_space, size;
+       pos_in_node_t stop_item;        /* item which estimating should not consider */
+       unsigned want;          /* number of units of item we want shifted */
+       coord_t source;         /* item being estimated */
+       item_plugin *iplug;
+
+       /* shifting to left/right starts from first/last units of
+          @shift->wish_stop.node */
+       if (shift->pend == SHIFT_LEFT) {
+               coord_init_first_unit(&source, shift->wish_stop.node);
+       } else {
+               coord_init_last_unit(&source, shift->wish_stop.node);
+       }
+       shift->real_stop = source;
+
+       /* free space in target node and number of items in source */
+       target_free_space = znode_free_space(shift->target);
+
+       shift->everything = 0;
+       if (!node_is_empty(shift->target)) {
+               /* target node is not empty, check for boundary items
+                  mergeability */
+               coord_t to;
+
+               /* item we try to merge @source with */
+               if (shift->pend == SHIFT_LEFT) {
+                       coord_init_last_unit(&to, shift->target);
+               } else {
+                       coord_init_first_unit(&to, shift->target);
+               }
+
+               if ((shift->pend == SHIFT_LEFT) ? are_items_mergeable(&to,
+                                                                     &source) :
+                   are_items_mergeable(&source, &to)) {
+                       /* how many units of @source do we want to merge to
+                          item @to */
+                       want =
+                           wanted_units(&source, &shift->wish_stop,
+                                        shift->pend);
+
+                       /* how many units of @source we can merge to item
+                          @to */
+                       iplug = item_plugin_by_coord(&source);
+                       if (iplug->b.can_shift != NULL)
+                               shift->merging_units =
+                                   iplug->b.can_shift(target_free_space,
+                                                      &source, shift->target,
+                                                      shift->pend, &size,
+                                                      want);
+                       else {
+                               shift->merging_units = 0;
+                               size = 0;
+                       }
+                       shift->merging_bytes = size;
+                       shift->shift_bytes += size;
+                       /* update stop coord to be set to last unit of @source
+                          we can merge to @target */
+                       if (shift->merging_units)
+                               /* at least one unit can be shifted */
+                               shift->real_stop.unit_pos =
+                                   (shift->merging_units - source.unit_pos -
+                                    1) * shift->pend;
+                       else {
+                               /* nothing can be shifted */
+                               if (shift->pend == SHIFT_LEFT)
+                                       coord_init_before_first_item(&shift->
+                                                                    real_stop,
+                                                                    source.
+                                                                    node);
+                               else
+                                       coord_init_after_last_item(&shift->
+                                                                  real_stop,
+                                                                  source.node);
+                       }
+                       assert("nikita-2081", shift->real_stop.unit_pos + 1);
+
+                       if (shift->merging_units != want) {
+                               /* we could not copy as many as we want, so,
+                                  there is no reason for estimating any
+                                  longer */
+                               return;
+                       }
+
+                       target_free_space -= size;
+                       coord_add_item_pos(&source, shift->pend);
+               }
+       }
+
+       /* number of item nothing of which we want to shift */
+       stop_item = shift->wish_stop.item_pos + shift->pend;
+
+       /* calculate how many items can be copied into given free
+          space as whole */
+       for (; source.item_pos != stop_item;
+            coord_add_item_pos(&source, shift->pend)) {
+               if (shift->pend == SHIFT_RIGHT)
+                       source.unit_pos = coord_last_unit_pos(&source);
+
+               /* how many units of @source do we want to copy */
+               want = wanted_units(&source, &shift->wish_stop, shift->pend);
+
+               if (want == coord_last_unit_pos(&source) + 1) {
+                       /* we want this item to be copied entirely */
+                       size =
+                           item_length_by_coord(&source) +
+                           item_creation_overhead(&source);
+                       if (size <= target_free_space) {
+                               /* item fits into target node as whole */
+                               target_free_space -= size;
+                               shift->shift_bytes +=
+                                   size - item_creation_overhead(&source);
+                               shift->entire_bytes +=
+                                   size - item_creation_overhead(&source);
+                               shift->entire++;
+
+                               /* update shift->real_stop coord to be set to
+                                  last unit of @source we can merge to
+                                  @target */
+                               shift->real_stop = source;
+                               if (shift->pend == SHIFT_LEFT)
+                                       shift->real_stop.unit_pos =
+                                           coord_last_unit_pos(&shift->
+                                                               real_stop);
+                               else
+                                       shift->real_stop.unit_pos = 0;
+                               continue;
+                       }
+               }
+
+               /* we reach here only for an item which does not fit into
+                  target node in its entirety. This item may be either
+                  partially shifted, or not shifted at all. We will have to
+                  create new item in target node, so decrease amout of free
+                  space by an item creation overhead. We can reach here also
+                  if stop coord is in this item */
+               if (target_free_space >=
+                   (unsigned)item_creation_overhead(&source)) {
+                       target_free_space -= item_creation_overhead(&source);
+                       iplug = item_plugin_by_coord(&source);
+                       if (iplug->b.can_shift) {
+                               shift->part_units = iplug->b.can_shift(target_free_space,
+                                                                      &source,
+                                                                      NULL, /* target */
+                                                                      shift->pend,
+                                                                      &size,
+                                                                      want);
+                       } else {
+                               target_free_space = 0;
+                               shift->part_units = 0;
+                               size = 0;
+                       }
+               } else {
+                       target_free_space = 0;
+                       shift->part_units = 0;
+                       size = 0;
+               }
+               shift->part_bytes = size;
+               shift->shift_bytes += size;
+
+               /* set @shift->real_stop to last unit of @source we can merge
+                  to @shift->target */
+               if (shift->part_units) {
+                       shift->real_stop = source;
+                       shift->real_stop.unit_pos =
+                           (shift->part_units - source.unit_pos -
+                            1) * shift->pend;
+                       assert("nikita-2082", shift->real_stop.unit_pos + 1);
+               }
+
+               if (want != shift->part_units)
+                       /* not everything wanted were shifted */
+                       return;
+               break;
+       }
+
+       shift->everything = 1;
+}
+
+static void
+copy_units(coord_t * target, coord_t * source, unsigned from, unsigned count,
+          shift_direction dir, unsigned free_space)
+{
+       item_plugin *iplug;
+
+       assert("nikita-1463", target != NULL);
+       assert("nikita-1464", source != NULL);
+       assert("nikita-1465", from + count <= coord_num_units(source));
+
+       iplug = item_plugin_by_coord(source);
+       assert("nikita-1468", iplug == item_plugin_by_coord(target));
+       iplug->b.copy_units(target, source, from, count, dir, free_space);
+
+       if (dir == SHIFT_RIGHT) {
+               /* FIXME-VS: this looks not necessary. update_item_key was
+                  called already by copy_units method */
+               reiser4_key split_key;
+
+               assert("nikita-1469", target->unit_pos == 0);
+
+               unit_key_by_coord(target, &split_key);
+               node_plugin_by_coord(target)->update_item_key(target,
+                                                             &split_key, NULL);
+       }
+}
+
+/* copy part of @shift->real_stop.node starting either from its beginning or
+   from its end and ending at @shift->real_stop to either the end or the
+   beginning of @shift->target */
+static void copy(struct shift_params *shift)
+{
+       node40_header *nh;
+       coord_t from;
+       coord_t to;
+       item_header40 *from_ih, *to_ih;
+       int free_space_start;
+       int new_items;
+       unsigned old_items;
+       int old_offset;
+       unsigned i;
+
+       nh = node40_node_header(shift->target);
+       free_space_start = nh40_get_free_space_start(nh);
+       old_items = nh40_get_num_items(nh);
+       new_items = shift->entire + (shift->part_units ? 1 : 0);
+       assert("vs-185",
+              shift->shift_bytes ==
+              shift->merging_bytes + shift->entire_bytes + shift->part_bytes);
+
+       from = shift->wish_stop;
+
+       coord_init_first_unit(&to, shift->target);
+
+       /* NOTE:NIKITA->VS not sure what I am doing: shift->target is empty,
+          hence to.between is set to EMPTY_NODE above. Looks like we want it
+          to be AT_UNIT.
+
+          Oh, wonders of ->betweeness...
+
+        */
+       to.between = AT_UNIT;
+
+       if (shift->pend == SHIFT_LEFT) {
+               /* copying to left */
+
+               coord_set_item_pos(&from, 0);
+               from_ih = node40_ih_at(from.node, 0);
+
+               coord_set_item_pos(&to,
+                                  node40_num_of_items_internal(to.node) - 1);
+               if (shift->merging_units) {
+                       /* expand last item, so that plugin methods will see
+                          correct data */
+                       free_space_start += shift->merging_bytes;
+                       nh40_set_free_space_start(nh,
+                                                 (unsigned)free_space_start);
+                       nh40_set_free_space(nh,
+                                           nh40_get_free_space(nh) -
+                                           shift->merging_bytes);
+
+                       /* appending last item of @target */
+                       copy_units(&to, &from, 0,       /* starting from 0-th unit */
+                                  shift->merging_units, SHIFT_LEFT,
+                                  shift->merging_bytes);
+                       coord_inc_item_pos(&from);
+                       from_ih--;
+                       coord_inc_item_pos(&to);
+               }
+
+               to_ih = node40_ih_at(shift->target, old_items);
+               if (shift->entire) {
+                       /* copy @entire items entirely */
+
+                       /* copy item headers */
+                       memcpy(to_ih - shift->entire + 1,
+                              from_ih - shift->entire + 1,
+                              shift->entire * sizeof(item_header40));
+                       /* update item header offset */
+                       old_offset = ih40_get_offset(from_ih);
+                       /* AUDIT: Looks like if we calculate old_offset + free_space_start here instead of just old_offset, we can perform one "add" operation less per each iteration */
+                       for (i = 0; i < shift->entire; i++, to_ih--, from_ih--)
+                               ih40_set_offset(to_ih,
+                                               ih40_get_offset(from_ih) -
+                                               old_offset + free_space_start);
+
+                       /* copy item bodies */
+                       memcpy(zdata(shift->target) + free_space_start, zdata(from.node) + old_offset,  /*ih40_get_offset (from_ih), */
+                              shift->entire_bytes);
+
+                       coord_add_item_pos(&from, (int)shift->entire);
+                       coord_add_item_pos(&to, (int)shift->entire);
+               }
+
+               nh40_set_free_space_start(nh,
+                                         free_space_start +
+                                         shift->shift_bytes -
+                                         shift->merging_bytes);
+               nh40_set_free_space(nh,
+                                   nh40_get_free_space(nh) -
+                                   (shift->shift_bytes - shift->merging_bytes +
+                                    sizeof(item_header40) * new_items));
+
+               /* update node header */
+               node40_set_num_items(shift->target, nh, old_items + new_items);
+               assert("vs-170",
+                      nh40_get_free_space(nh) < znode_size(shift->target));
+
+               if (shift->part_units) {
+                       /* copy heading part (@part units) of @source item as
+                          a new item into @target->node */
+
+                       /* copy item header of partially copied item */
+                       coord_set_item_pos(&to,
+                                          node40_num_of_items_internal(to.node)
+                                          - 1);
+                       memcpy(to_ih, from_ih, sizeof(item_header40));
+                       ih40_set_offset(to_ih,
+                                       nh40_get_free_space_start(nh) -
+                                       shift->part_bytes);
+                       if (item_plugin_by_coord(&to)->b.init)
+                               item_plugin_by_coord(&to)->b.init(&to, &from,
+                                                                 NULL);
+                       copy_units(&to, &from, 0, shift->part_units, SHIFT_LEFT,
+                                  shift->part_bytes);
+               }
+
+       } else {
+               /* copying to right */
+
+               coord_set_item_pos(&from,
+                                  node40_num_of_items_internal(from.node) - 1);
+               from_ih = node40_ih_at_coord(&from);
+
+               coord_set_item_pos(&to, 0);
+
+               /* prepare space for new items */
+               memmove(zdata(to.node) + sizeof(node40_header) +
+                       shift->shift_bytes,
+                       zdata(to.node) + sizeof(node40_header),
+                       free_space_start - sizeof(node40_header));
+               /* update item headers of moved items */
+               to_ih = node40_ih_at(to.node, 0);
+               /* first item gets @merging_bytes longer. free space appears
+                  at its beginning */
+               if (!node_is_empty(to.node))
+                       ih40_set_offset(to_ih,
+                                       ih40_get_offset(to_ih) +
+                                       shift->shift_bytes -
+                                       shift->merging_bytes);
+
+               for (i = 1; i < old_items; i++)
+                       ih40_set_offset(to_ih - i,
+                                       ih40_get_offset(to_ih - i) +
+                                       shift->shift_bytes);
+
+               /* move item headers to make space for new items */
+               memmove(to_ih - old_items + 1 - new_items,
+                       to_ih - old_items + 1,
+                       sizeof(item_header40) * old_items);
+               to_ih -= (new_items - 1);
+
+               nh40_set_free_space_start(nh,
+                                         free_space_start +
+                                         shift->shift_bytes);
+               nh40_set_free_space(nh,
+                                   nh40_get_free_space(nh) -
+                                   (shift->shift_bytes +
+                                    sizeof(item_header40) * new_items));
+
+               /* update node header */
+               node40_set_num_items(shift->target, nh, old_items + new_items);
+               assert("vs-170",
+                      nh40_get_free_space(nh) < znode_size(shift->target));
+
+               if (shift->merging_units) {
+                       coord_add_item_pos(&to, new_items);
+                       to.unit_pos = 0;
+                       to.between = AT_UNIT;
+                       /* prepend first item of @to */
+                       copy_units(&to, &from,
+                                  coord_last_unit_pos(&from) -
+                                  shift->merging_units + 1,
+                                  shift->merging_units, SHIFT_RIGHT,
+                                  shift->merging_bytes);
+                       coord_dec_item_pos(&from);
+                       from_ih++;
+               }
+
+               if (shift->entire) {
+                       /* copy @entire items entirely */
+
+                       /* copy item headers */
+                       memcpy(to_ih, from_ih,
+                              shift->entire * sizeof(item_header40));
+
+                       /* update item header offset */
+                       old_offset =
+                           ih40_get_offset(from_ih + shift->entire - 1);
+                       /* AUDIT: old_offset + sizeof (node40_header) + shift->part_bytes calculation can be taken off the loop. */
+                       for (i = 0; i < shift->entire; i++, to_ih++, from_ih++)
+                               ih40_set_offset(to_ih,
+                                               ih40_get_offset(from_ih) -
+                                               old_offset +
+                                               sizeof(node40_header) +
+                                               shift->part_bytes);
+                       /* copy item bodies */
+                       coord_add_item_pos(&from, -(int)(shift->entire - 1));
+                       memcpy(zdata(to.node) + sizeof(node40_header) +
+                              shift->part_bytes, item_by_coord_node40(&from),
+                              shift->entire_bytes);
+                       coord_dec_item_pos(&from);
+               }
+
+               if (shift->part_units) {
+                       coord_set_item_pos(&to, 0);
+                       to.unit_pos = 0;
+                       to.between = AT_UNIT;
+                       /* copy heading part (@part units) of @source item as
+                          a new item into @target->node */
+
+                       /* copy item header of partially copied item */
+                       memcpy(to_ih, from_ih, sizeof(item_header40));
+                       ih40_set_offset(to_ih, sizeof(node40_header));
+                       if (item_plugin_by_coord(&to)->b.init)
+                               item_plugin_by_coord(&to)->b.init(&to, &from,
+                                                                 NULL);
+                       copy_units(&to, &from,
+                                  coord_last_unit_pos(&from) -
+                                  shift->part_units + 1, shift->part_units,
+                                  SHIFT_RIGHT, shift->part_bytes);
+               }
+       }
+}
+
+/* remove everything either before or after @fact_stop. Number of items
+   removed completely is returned */
+static int delete_copied(struct shift_params *shift)
+{
+       coord_t from;
+       coord_t to;
+       struct carry_cut_data cdata;
+
+       if (shift->pend == SHIFT_LEFT) {
+               /* we were shifting to left, remove everything from the
+                  beginning of @shift->wish_stop->node upto
+                  @shift->wish_stop */
+               coord_init_first_unit(&from, shift->real_stop.node);
+               to = shift->real_stop;
+
+               /* store old coordinate of unit which will be first after
+                  shift to left */
+               shift->u.future_first = to;
+               coord_next_unit(&shift->u.future_first);
+       } else {
+               /* we were shifting to right, remove everything from
+                  @shift->stop_coord upto to end of
+                  @shift->stop_coord->node */
+               from = shift->real_stop;
+               coord_init_last_unit(&to, from.node);
+
+               /* store old coordinate of unit which will be last after
+                  shift to right */
+               shift->u.future_last = from;
+               coord_prev_unit(&shift->u.future_last);
+       }
+
+       cdata.params.from = &from;
+       cdata.params.to = &to;
+       cdata.params.from_key = NULL;
+       cdata.params.to_key = NULL;
+       cdata.params.smallest_removed = NULL;
+       return cut_node40(&cdata, NULL);
+}
+
+/* something was moved between @left and @right. Add carry operation to @info
+   list to have carry to update delimiting key between them */
+static int
+prepare_for_update(znode * left, znode * right, carry_plugin_info * info)
+{
+       carry_op *op;
+       carry_node *cn;
+
+       if (info == NULL)
+               /* nowhere to send operation to. */
+               return 0;
+
+       if (!should_notify_parent(right))
+               return 0;
+
+       op = node_post_carry(info, COP_UPDATE, right, 1);
+       if (IS_ERR(op) || op == NULL)
+               return op ? PTR_ERR(op) : -EIO;
+
+       if (left != NULL) {
+               carry_node *reference;
+
+               if (info->doing)
+                       reference = insert_carry_node(info->doing,
+                                                     info->todo, left);
+               else
+                       reference = op->node;
+               assert("nikita-2992", reference != NULL);
+               cn = reiser4_add_carry(info->todo, POOLO_BEFORE, reference);
+               if (IS_ERR(cn))
+                       return PTR_ERR(cn);
+               cn->parent = 1;
+               cn->node = left;
+               if (ZF_ISSET(left, JNODE_ORPHAN))
+                       cn->left_before = 1;
+               op->u.update.left = cn;
+       } else
+               op->u.update.left = NULL;
+       return 0;
+}
+
+/* plugin->u.node.prepare_removal
+   to delete a pointer to @empty from the tree add corresponding carry
+   operation (delete) to @info list */
+int prepare_removal_node40(znode * empty, carry_plugin_info * info)
+{
+       carry_op *op;
+       reiser4_tree *tree;
+
+       if (!should_notify_parent(empty))
+               return 0;
+       /* already on a road to Styx */
+       if (ZF_ISSET(empty, JNODE_HEARD_BANSHEE))
+               return 0;
+       op = node_post_carry(info, COP_DELETE, empty, 1);
+       if (IS_ERR(op) || op == NULL)
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+
+       op->u.delete.child = NULL;
+       op->u.delete.flags = 0;
+
+       /* fare thee well */
+       tree = znode_get_tree(empty);
+       read_lock_tree(tree);
+       write_lock_dk(tree);
+       znode_set_ld_key(empty, znode_get_rd_key(empty));
+       if (znode_is_left_connected(empty) && empty->left)
+               znode_set_rd_key(empty->left, znode_get_rd_key(empty));
+       write_unlock_dk(tree);
+       read_unlock_tree(tree);
+
+       ZF_SET(empty, JNODE_HEARD_BANSHEE);
+       return 0;
+}
+
+/* something were shifted from @insert_coord->node to @shift->target, update
+   @insert_coord correspondingly */
+static void
+adjust_coord(coord_t * insert_coord, struct shift_params *shift, int removed,
+            int including_insert_coord)
+{
+       /* item plugin was invalidated by shifting */
+       coord_clear_iplug(insert_coord);
+
+       if (node_is_empty(shift->wish_stop.node)) {
+               assert("vs-242", shift->everything);
+               if (including_insert_coord) {
+                       if (shift->pend == SHIFT_RIGHT) {
+                               /* set @insert_coord before first unit of
+                                  @shift->target node */
+                               coord_init_before_first_item(insert_coord,
+                                                            shift->target);
+                       } else {
+                               /* set @insert_coord after last in target node */
+                               coord_init_after_last_item(insert_coord,
+                                                          shift->target);
+                       }
+               } else {
+                       /* set @insert_coord inside of empty node. There is
+                          only one possible coord within an empty
+                          node. init_first_unit will set that coord */
+                       coord_init_first_unit(insert_coord,
+                                             shift->wish_stop.node);
+               }
+               return;
+       }
+
+       if (shift->pend == SHIFT_RIGHT) {
+               /* there was shifting to right */
+               if (shift->everything) {
+                       /* everything wanted was shifted */
+                       if (including_insert_coord) {
+                               /* @insert_coord is set before first unit of
+                                  @to node */
+                               coord_init_before_first_item(insert_coord,
+                                                            shift->target);
+                               insert_coord->between = BEFORE_UNIT;
+                       } else {
+                               /* @insert_coord is set after last unit of
+                                  @insert->node */
+                               coord_init_last_unit(insert_coord,
+                                                    shift->wish_stop.node);
+                               insert_coord->between = AFTER_UNIT;
+                       }
+               }
+               return;
+       }
+
+       /* there was shifting to left */
+       if (shift->everything) {
+               /* everything wanted was shifted */
+               if (including_insert_coord) {
+                       /* @insert_coord is set after last unit in @to node */
+                       coord_init_after_last_item(insert_coord, shift->target);
+               } else {
+                       /* @insert_coord is set before first unit in the same
+                          node */
+                       coord_init_before_first_item(insert_coord,
+                                                    shift->wish_stop.node);
+               }
+               return;
+       }
+
+       /* FIXME-VS: the code below is complicated because with between ==
+          AFTER_ITEM unit_pos is set to 0 */
+
+       if (!removed) {
+               /* no items were shifted entirely */
+               assert("vs-195", shift->merging_units == 0
+                      || shift->part_units == 0);
+
+               if (shift->real_stop.item_pos == insert_coord->item_pos) {
+                       if (shift->merging_units) {
+                               if (insert_coord->between == AFTER_UNIT) {
+                                       assert("nikita-1441",
+                                              insert_coord->unit_pos >=
+                                              shift->merging_units);
+                                       insert_coord->unit_pos -=
+                                           shift->merging_units;
+                               } else if (insert_coord->between == BEFORE_UNIT) {
+                                       assert("nikita-2090",
+                                              insert_coord->unit_pos >
+                                              shift->merging_units);
+                                       insert_coord->unit_pos -=
+                                           shift->merging_units;
+                               }
+
+                               assert("nikita-2083",
+                                      insert_coord->unit_pos + 1);
+                       } else {
+                               if (insert_coord->between == AFTER_UNIT) {
+                                       assert("nikita-1442",
+                                              insert_coord->unit_pos >=
+                                              shift->part_units);
+                                       insert_coord->unit_pos -=
+                                           shift->part_units;
+                               } else if (insert_coord->between == BEFORE_UNIT) {
+                                       assert("nikita-2089",
+                                              insert_coord->unit_pos >
+                                              shift->part_units);
+                                       insert_coord->unit_pos -=
+                                           shift->part_units;
+                               }
+
+                               assert("nikita-2084",
+                                      insert_coord->unit_pos + 1);
+                       }
+               }
+               return;
+       }
+
+       /* we shifted to left and there was no enough space for everything */
+       switch (insert_coord->between) {
+       case AFTER_UNIT:
+       case BEFORE_UNIT:
+               if (shift->real_stop.item_pos == insert_coord->item_pos)
+                       insert_coord->unit_pos -= shift->part_units;
+       case AFTER_ITEM:
+               coord_add_item_pos(insert_coord, -removed);
+               break;
+       default:
+               impossible("nikita-2087", "not ready");
+       }
+       assert("nikita-2085", insert_coord->unit_pos + 1);
+}
+
+static int call_shift_hooks(struct shift_params *shift)
+{
+       unsigned i, shifted;
+       coord_t coord;
+       item_plugin *iplug;
+
+       assert("vs-275", !node_is_empty(shift->target));
+
+       /* number of items shift touches */
+       shifted =
+           shift->entire + (shift->merging_units ? 1 : 0) +
+           (shift->part_units ? 1 : 0);
+
+       if (shift->pend == SHIFT_LEFT) {
+               /* moved items are at the end */
+               coord_init_last_unit(&coord, shift->target);
+               coord.unit_pos = 0;
+
+               assert("vs-279", shift->pend == 1);
+               for (i = 0; i < shifted; i++) {
+                       unsigned from, count;
+
+                       iplug = item_plugin_by_coord(&coord);
+                       if (i == 0 && shift->part_units) {
+                               assert("vs-277",
+                                      coord_num_units(&coord) ==
+                                      shift->part_units);
+                               count = shift->part_units;
+                               from = 0;
+                       } else if (i == shifted - 1 && shift->merging_units) {
+                               count = shift->merging_units;
+                               from = coord_num_units(&coord) - count;
+                       } else {
+                               count = coord_num_units(&coord);
+                               from = 0;
+                       }
+
+                       if (iplug->b.shift_hook) {
+                               iplug->b.shift_hook(&coord, from, count,
+                                                   shift->wish_stop.node);
+                       }
+                       coord_add_item_pos(&coord, -shift->pend);
+               }
+       } else {
+               /* moved items are at the beginning */
+               coord_init_first_unit(&coord, shift->target);
+
+               assert("vs-278", shift->pend == -1);
+               for (i = 0; i < shifted; i++) {
+                       unsigned from, count;
+
+                       iplug = item_plugin_by_coord(&coord);
+                       if (i == 0 && shift->part_units) {
+                               assert("vs-277",
+                                      coord_num_units(&coord) ==
+                                      shift->part_units);
+                               count = coord_num_units(&coord);
+                               from = 0;
+                       } else if (i == shifted - 1 && shift->merging_units) {
+                               count = shift->merging_units;
+                               from = 0;
+                       } else {
+                               count = coord_num_units(&coord);
+                               from = 0;
+                       }
+
+                       if (iplug->b.shift_hook) {
+                               iplug->b.shift_hook(&coord, from, count,
+                                                   shift->wish_stop.node);
+                       }
+                       coord_add_item_pos(&coord, -shift->pend);
+               }
+       }
+
+       return 0;
+}
+
+/* shift to left is completed. Return 1 if unit @old was moved to left neighbor */
+static int
+unit_moved_left(const struct shift_params *shift, const coord_t * old)
+{
+       assert("vs-944", shift->real_stop.node == old->node);
+
+       if (shift->real_stop.item_pos < old->item_pos)
+               return 0;
+       if (shift->real_stop.item_pos == old->item_pos) {
+               if (shift->real_stop.unit_pos < old->unit_pos)
+                       return 0;
+       }
+       return 1;
+}
+
+/* shift to right is completed. Return 1 if unit @old was moved to right
+   neighbor */
+static int
+unit_moved_right(const struct shift_params *shift, const coord_t * old)
+{
+       assert("vs-944", shift->real_stop.node == old->node);
+
+       if (shift->real_stop.item_pos > old->item_pos)
+               return 0;
+       if (shift->real_stop.item_pos == old->item_pos) {
+               if (shift->real_stop.unit_pos > old->unit_pos)
+                       return 0;
+       }
+       return 1;
+}
+
+/* coord @old was set in node from which shift was performed. What was shifted
+   is stored in @shift. Update @old correspondingly to performed shift */
+static coord_t *adjust_coord2(const struct shift_params *shift,
+                             const coord_t * old, coord_t * new)
+{
+       coord_clear_iplug(new);
+       new->between = old->between;
+
+       coord_clear_iplug(new);
+       if (old->node == shift->target) {
+               if (shift->pend == SHIFT_LEFT) {
+                       /* coord which is set inside of left neighbor does not
+                          change during shift to left */
+                       coord_dup(new, old);
+                       return new;
+               }
+               new->node = old->node;
+               coord_set_item_pos(new,
+                                  old->item_pos + shift->entire +
+                                  (shift->part_units ? 1 : 0));
+               new->unit_pos = old->unit_pos;
+               if (old->item_pos == 0 && shift->merging_units)
+                       new->unit_pos += shift->merging_units;
+               return new;
+       }
+
+       assert("vs-977", old->node == shift->wish_stop.node);
+       if (shift->pend == SHIFT_LEFT) {
+               if (unit_moved_left(shift, old)) {
+                       /* unit @old moved to left neighbor. Calculate its
+                          coordinate there */
+                       new->node = shift->target;
+                       coord_set_item_pos(new,
+                                          node_num_items(shift->target) -
+                                          shift->entire -
+                                          (shift->part_units ? 1 : 0) +
+                                          old->item_pos);
+
+                       new->unit_pos = old->unit_pos;
+                       if (shift->merging_units) {
+                               coord_dec_item_pos(new);
+                               if (old->item_pos == 0) {
+                                       /* unit_pos only changes if item got
+                                          merged */
+                                       new->unit_pos =
+                                           coord_num_units(new) -
+                                           (shift->merging_units -
+                                            old->unit_pos);
+                               }
+                       }
+               } else {
+                       /* unit @old did not move to left neighbor.
+
+                          Use _nocheck, because @old is outside of its node.
+                        */
+                       coord_dup_nocheck(new, old);
+                       coord_add_item_pos(new,
+                                          -shift->u.future_first.item_pos);
+                       if (new->item_pos == 0)
+                               new->unit_pos -= shift->u.future_first.unit_pos;
+               }
+       } else {
+               if (unit_moved_right(shift, old)) {
+                       /* unit @old moved to right neighbor */
+                       new->node = shift->target;
+                       coord_set_item_pos(new,
+                                          old->item_pos -
+                                          shift->real_stop.item_pos);
+                       if (new->item_pos == 0) {
+                               /* unit @old might change unit pos */
+                               coord_set_item_pos(new,
+                                                  old->unit_pos -
+                                                  shift->real_stop.unit_pos);
+                       }
+               } else {
+                       /* unit @old did not move to right neighbor, therefore
+                          it did not change */
+                       coord_dup(new, old);
+               }
+       }
+       coord_set_iplug(new, item_plugin_by_coord(new));
+       return new;
+}
+
+/* this is called when shift is completed (something of source node is copied
+   to target and deleted in source) to update all taps set in current
+   context */
+static void update_taps(const struct shift_params *shift)
+{
+       tap_t *tap;
+       coord_t new;
+
+       for_all_taps(tap) {
+               /* update only taps set to nodes participating in shift */
+               if (tap->coord->node == shift->wish_stop.node
+                   || tap->coord->node == shift->target)
+                       tap_to_coord(tap,
+                                    adjust_coord2(shift, tap->coord, &new));
+       }
+}
+
+#if REISER4_DEBUG
+
+struct shift_check {
+       reiser4_key key;
+       __u16 plugin_id;
+       union {
+               __u64 bytes;
+               __u64 entries;
+               void *unused;
+       } u;
+};
+
+void *shift_check_prepare(const znode * left, const znode * right)
+{
+       pos_in_node_t i, nr_items;
+       int mergeable;
+       struct shift_check *data;
+       item_header40 *ih;
+
+       if (node_is_empty(left) || node_is_empty(right))
+               mergeable = 0;
+       else {
+               coord_t l, r;
+
+               coord_init_last_unit(&l, left);
+               coord_init_first_unit(&r, right);
+               mergeable = are_items_mergeable(&l, &r);
+       }
+       nr_items =
+           node40_num_of_items_internal(left) +
+           node40_num_of_items_internal(right) - (mergeable ? 1 : 0);
+       data =
+               kmalloc(sizeof(struct shift_check) * nr_items,
+                       reiser4_ctx_gfp_mask_get());
+       if (data != NULL) {
+               coord_t coord;
+               pos_in_node_t item_pos;
+
+               coord_init_first_unit(&coord, left);
+               i = 0;
+
+               for (item_pos = 0;
+                    item_pos < node40_num_of_items_internal(left);
+                    item_pos++) {
+
+                       coord_set_item_pos(&coord, item_pos);
+                       ih = node40_ih_at_coord(&coord);
+
+                       data[i].key = ih->key;
+                       data[i].plugin_id = le16_to_cpu(get_unaligned(&ih->plugin_id));
+                       switch (data[i].plugin_id) {
+                       case CTAIL_ID:
+                       case FORMATTING_ID:
+                               data[i].u.bytes = coord_num_units(&coord);
+                               break;
+                       case EXTENT_POINTER_ID:
+                               data[i].u.bytes =
+                                       reiser4_extent_size(&coord,
+                                                      coord_num_units(&coord));
+                               break;
+                       case COMPOUND_DIR_ID:
+                               data[i].u.entries = coord_num_units(&coord);
+                               break;
+                       default:
+                               data[i].u.unused = NULL;
+                               break;
+                       }
+                       i++;
+               }
+
+               coord_init_first_unit(&coord, right);
+
+               if (mergeable) {
+                       assert("vs-1609", i != 0);
+
+                       ih = node40_ih_at_coord(&coord);
+
+                       assert("vs-1589",
+                              data[i - 1].plugin_id ==
+                              le16_to_cpu(get_unaligned(&ih->plugin_id)));
+                       switch (data[i - 1].plugin_id) {
+                       case CTAIL_ID:
+                       case FORMATTING_ID:
+                               data[i - 1].u.bytes += coord_num_units(&coord);
+                               break;
+                       case EXTENT_POINTER_ID:
+                               data[i - 1].u.bytes +=
+                                   reiser4_extent_size(&coord,
+                                               coord_num_units(&coord));
+                               break;
+                       case COMPOUND_DIR_ID:
+                               data[i - 1].u.entries +=
+                                   coord_num_units(&coord);
+                               break;
+                       default:
+                               impossible("vs-1605", "wrong mergeable item");
+                               break;
+                       }
+                       item_pos = 1;
+               } else
+                       item_pos = 0;
+               for (; item_pos < node40_num_of_items_internal(right);
+                    item_pos++) {
+
+                       assert("vs-1604", i < nr_items);
+                       coord_set_item_pos(&coord, item_pos);
+                       ih = node40_ih_at_coord(&coord);
+
+                       data[i].key = ih->key;
+                       data[i].plugin_id = le16_to_cpu(get_unaligned(&ih->plugin_id));
+                       switch (data[i].plugin_id) {
+                       case CTAIL_ID:
+                       case FORMATTING_ID:
+                               data[i].u.bytes = coord_num_units(&coord);
+                               break;
+                       case EXTENT_POINTER_ID:
+                               data[i].u.bytes =
+                                   reiser4_extent_size(&coord,
+                                               coord_num_units(&coord));
+                               break;
+                       case COMPOUND_DIR_ID:
+                               data[i].u.entries = coord_num_units(&coord);
+                               break;
+                       default:
+                               data[i].u.unused = NULL;
+                               break;
+                       }
+                       i++;
+               }
+               assert("vs-1606", i == nr_items);
+       }
+       return data;
+}
+
+void shift_check(void *vp, const znode * left, const znode * right)
+{
+       pos_in_node_t i, nr_items;
+       coord_t coord;
+       __u64 last_bytes;
+       int mergeable;
+       item_header40 *ih;
+       pos_in_node_t item_pos;
+       struct shift_check *data;
+
+       data = (struct shift_check *)vp;
+
+       if (data == NULL)
+               return;
+
+       if (node_is_empty(left) || node_is_empty(right))
+               mergeable = 0;
+       else {
+               coord_t l, r;
+
+               coord_init_last_unit(&l, left);
+               coord_init_first_unit(&r, right);
+               mergeable = are_items_mergeable(&l, &r);
+       }
+
+       nr_items =
+           node40_num_of_items_internal(left) +
+           node40_num_of_items_internal(right) - (mergeable ? 1 : 0);
+
+       i = 0;
+       last_bytes = 0;
+
+       coord_init_first_unit(&coord, left);
+
+       for (item_pos = 0; item_pos < node40_num_of_items_internal(left);
+            item_pos++) {
+
+               coord_set_item_pos(&coord, item_pos);
+               ih = node40_ih_at_coord(&coord);
+
+               assert("vs-1611", i == item_pos);
+               assert("vs-1590", keyeq(&ih->key, &data[i].key));
+               assert("vs-1591",
+                      le16_to_cpu(get_unaligned(&ih->plugin_id)) == data[i].plugin_id);
+               if ((i < (node40_num_of_items_internal(left) - 1))
+                   || !mergeable) {
+                       switch (data[i].plugin_id) {
+                       case CTAIL_ID:
+                       case FORMATTING_ID:
+                               assert("vs-1592",
+                                      data[i].u.bytes ==
+                                      coord_num_units(&coord));
+                               break;
+                       case EXTENT_POINTER_ID:
+                               assert("vs-1593",
+                                      data[i].u.bytes ==
+                                      reiser4_extent_size(&coord,
+                                                          coord_num_units
+                                                          (&coord)));
+                               break;
+                       case COMPOUND_DIR_ID:
+                               assert("vs-1594",
+                                      data[i].u.entries ==
+                                      coord_num_units(&coord));
+                               break;
+                       default:
+                               break;
+                       }
+               }
+               if (item_pos == (node40_num_of_items_internal(left) - 1)
+                   && mergeable) {
+                       switch (data[i].plugin_id) {
+                       case CTAIL_ID:
+                       case FORMATTING_ID:
+                               last_bytes = coord_num_units(&coord);
+                               break;
+                       case EXTENT_POINTER_ID:
+                               last_bytes =
+                                   reiser4_extent_size(&coord,
+                                               coord_num_units(&coord));
+                               break;
+                       case COMPOUND_DIR_ID:
+                               last_bytes = coord_num_units(&coord);
+                               break;
+                       default:
+                               impossible("vs-1595", "wrong mergeable item");
+                               break;
+                       }
+               }
+               i++;
+       }
+
+       coord_init_first_unit(&coord, right);
+       if (mergeable) {
+               ih = node40_ih_at_coord(&coord);
+
+               assert("vs-1589",
+                      data[i - 1].plugin_id == le16_to_cpu(get_unaligned(&ih->plugin_id)));
+               assert("vs-1608", last_bytes != 0);
+               switch (data[i - 1].plugin_id) {
+               case CTAIL_ID:
+               case FORMATTING_ID:
+                       assert("vs-1596",
+                              data[i - 1].u.bytes ==
+                              last_bytes + coord_num_units(&coord));
+                       break;
+
+               case EXTENT_POINTER_ID:
+                       assert("vs-1597",
+                              data[i - 1].u.bytes ==
+                              last_bytes + reiser4_extent_size(&coord,
+                                                               coord_num_units
+                                                               (&coord)));
+                       break;
+
+               case COMPOUND_DIR_ID:
+                       assert("vs-1598",
+                              data[i - 1].u.bytes ==
+                              last_bytes + coord_num_units(&coord));
+                       break;
+               default:
+                       impossible("vs-1599", "wrong mergeable item");
+                       break;
+               }
+               item_pos = 1;
+       } else
+               item_pos = 0;
+
+       for (; item_pos < node40_num_of_items_internal(right); item_pos++) {
+
+               coord_set_item_pos(&coord, item_pos);
+               ih = node40_ih_at_coord(&coord);
+
+               assert("vs-1612", keyeq(&ih->key, &data[i].key));
+               assert("vs-1613",
+                      le16_to_cpu(get_unaligned(&ih->plugin_id)) == data[i].plugin_id);
+               switch (data[i].plugin_id) {
+               case CTAIL_ID:
+               case FORMATTING_ID:
+                       assert("vs-1600",
+                              data[i].u.bytes == coord_num_units(&coord));
+                       break;
+               case EXTENT_POINTER_ID:
+                       assert("vs-1601",
+                              data[i].u.bytes ==
+                              reiser4_extent_size(&coord,
+                                                  coord_num_units
+                                                  (&coord)));
+                       break;
+               case COMPOUND_DIR_ID:
+                       assert("vs-1602",
+                              data[i].u.entries == coord_num_units(&coord));
+                       break;
+               default:
+                       break;
+               }
+               i++;
+       }
+
+       assert("vs-1603", i == nr_items);
+       kfree(data);
+}
+
+#endif
+
+/* plugin->u.node.shift
+   look for description of this method in plugin/node/node.h */
+int shift_node40(coord_t * from, znode * to, shift_direction pend, int delete_child,   /* if @from->node becomes empty - it will be
+                                                                                          deleted from the tree if this is set to 1 */
+                int including_stop_coord, carry_plugin_info * info)
+{
+       struct shift_params shift;
+       int result;
+       znode *left, *right;
+       znode *source;
+       int target_empty;
+
+       assert("nikita-2161", coord_check(from));
+
+       memset(&shift, 0, sizeof(shift));
+       shift.pend = pend;
+       shift.wish_stop = *from;
+       shift.target = to;
+
+       assert("nikita-1473", znode_is_write_locked(from->node));
+       assert("nikita-1474", znode_is_write_locked(to));
+
+       source = from->node;
+
+       /* set @shift.wish_stop to rightmost/leftmost unit among units we want
+          shifted */
+       if (pend == SHIFT_LEFT) {
+               result = coord_set_to_left(&shift.wish_stop);
+               left = to;
+               right = from->node;
+       } else {
+               result = coord_set_to_right(&shift.wish_stop);
+               left = from->node;
+               right = to;
+       }
+
+       if (result) {
+               /* move insertion coord even if there is nothing to move */
+               if (including_stop_coord) {
+                       /* move insertion coord (@from) */
+                       if (pend == SHIFT_LEFT) {
+                               /* after last item in target node */
+                               coord_init_after_last_item(from, to);
+                       } else {
+                               /* before first item in target node */
+                               coord_init_before_first_item(from, to);
+                       }
+               }
+
+               if (delete_child && node_is_empty(shift.wish_stop.node))
+                       result =
+                           prepare_removal_node40(shift.wish_stop.node, info);
+               else
+                       result = 0;
+               /* there is nothing to shift */
+               assert("nikita-2078", coord_check(from));
+               return result;
+       }
+
+       target_empty = node_is_empty(to);
+
+       /* when first node plugin with item body compression is implemented,
+          this must be changed to call node specific plugin */
+
+       /* shift->stop_coord is updated to last unit which really will be
+          shifted */
+       estimate_shift(&shift, get_current_context());
+       if (!shift.shift_bytes) {
+               /* we could not shift anything */
+               assert("nikita-2079", coord_check(from));
+               return 0;
+       }
+
+       copy(&shift);
+
+       /* result value of this is important. It is used by adjust_coord below */
+       result = delete_copied(&shift);
+
+       assert("vs-1610", result >= 0);
+       assert("vs-1471",
+              ((reiser4_context *) current->journal_info)->magic ==
+              context_magic);
+
+       /* item which has been moved from one node to another might want to do
+          something on that event. This can be done by item's shift_hook
+          method, which will be now called for every moved items */
+       call_shift_hooks(&shift);
+
+       assert("vs-1472",
+              ((reiser4_context *) current->journal_info)->magic ==
+              context_magic);
+
+       update_taps(&shift);
+
+       assert("vs-1473",
+              ((reiser4_context *) current->journal_info)->magic ==
+              context_magic);
+
+       /* adjust @from pointer in accordance with @including_stop_coord flag
+          and amount of data which was really shifted */
+       adjust_coord(from, &shift, result, including_stop_coord);
+
+       if (target_empty)
+               /*
+                * items were shifted into empty node. Update delimiting key.
+                */
+               result = prepare_for_update(NULL, left, info);
+
+       /* add update operation to @info, which is the list of operations to
+          be performed on a higher level */
+       result = prepare_for_update(left, right, info);
+       if (!result && node_is_empty(source) && delete_child) {
+               /* all contents of @from->node is moved to @to and @from->node
+                  has to be removed from the tree, so, on higher level we
+                  will be removing the pointer to node @from->node */
+               result = prepare_removal_node40(source, info);
+       }
+       assert("nikita-2080", coord_check(from));
+       return result ? result : (int)shift.shift_bytes;
+}
+
+/* plugin->u.node.fast_insert()
+   look for description of this method in plugin/node/node.h */
+int fast_insert_node40(const coord_t * coord UNUSED_ARG /* node to query */ )
+{
+       return 1;
+}
+
+/* plugin->u.node.fast_paste()
+   look for description of this method in plugin/node/node.h */
+int fast_paste_node40(const coord_t * coord UNUSED_ARG /* node to query */ )
+{
+       return 1;
+}
+
+/* plugin->u.node.fast_cut()
+   look for description of this method in plugin/node/node.h */
+int fast_cut_node40(const coord_t * coord UNUSED_ARG /* node to query */ )
+{
+       return 1;
+}
+
+/* plugin->u.node.modify - not defined */
+
+/* plugin->u.node.max_item_size */
+int max_item_size_node40(void)
+{
+       return reiser4_get_current_sb()->s_blocksize - sizeof(node40_header) -
+           sizeof(item_header40);
+}
+
+/* plugin->u.node.set_item_plugin */
+int set_item_plugin_node40(coord_t *coord, item_id id)
+{
+       item_header40 *ih;
+
+       ih = node40_ih_at_coord(coord);
+       put_unaligned(cpu_to_le16(id), &ih->plugin_id);
+       coord->iplugid = id;
+       return 0;
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/node/node40.h linux-2.6.20/fs/reiser4/plugin/node/node40.h
--- linux-2.6.20.orig/fs/reiser4/plugin/node/node40.h   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/node/node40.h        2007-05-06 14:50:43.835018219 +0400
@@ -0,0 +1,125 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined( __REISER4_NODE40_H__ )
+#define __REISER4_NODE40_H__
+
+#include "../../forward.h"
+#include "../../dformat.h"
+#include "node.h"
+
+#include <linux/types.h>
+
+/* format of node header for 40 node layouts. Keep bloat out of this struct.  */
+typedef struct node40_header {
+       /* identifier of node plugin. Must be located at the very beginning
+          of a node. */
+       common_node_header common_header;       /* this is 16 bits */
+       /* number of items. Should be first element in the node header,
+          because we haven't yet finally decided whether it shouldn't go into
+          common_header.
+        */
+/* NIKITA-FIXME-HANS: Create a macro such that if there is only one
+ * node format at compile time, and it is this one, accesses do not function dereference when
+ * accessing these fields (and otherwise they do).  Probably 80% of users will only have one node format at a time throughout the life of reiser4.  */
+       d16 nr_items;
+       /* free space in node measured in bytes */
+       d16 free_space;
+       /* offset to start of free space in node */
+       d16 free_space_start;
+       /* for reiser4_fsck.  When information about what is a free
+          block is corrupted, and we try to recover everything even
+          if marked as freed, then old versions of data may
+          duplicate newer versions, and this field allows us to
+          restore the newer version.  Also useful for when users
+          who don't have the new trashcan installed on their linux distro
+          delete the wrong files and send us desperate emails
+          offering $25 for them back.  */
+
+       /* magic field we need to tell formatted nodes NIKITA-FIXME-HANS: improve this comment */
+       d32 magic;
+       /* flushstamp is made of mk_id and write_counter. mk_id is an
+          id generated randomly at mkreiserfs time. So we can just
+          skip all nodes with different mk_id. write_counter is d64
+          incrementing counter of writes on disk. It is used for
+          choosing the newest data at fsck time. NIKITA-FIXME-HANS: why was field name changed but not comment? */
+
+       d32 mkfs_id;
+       d64 flush_id;
+       /* node flags to be used by fsck (reiser4ck or reiser4fsck?)
+          and repacker NIKITA-FIXME-HANS: say more or reference elsewhere that says more */
+       d16 flags;
+
+       /* 1 is leaf level, 2 is twig level, root is the numerically
+          largest level */
+       d8 level;
+
+       d8 pad;
+} PACKED node40_header;
+
+/* item headers are not standard across all node layouts, pass
+   pos_in_node to functions instead */
+typedef struct item_header40 {
+       /* key of item */
+       /*  0 */ reiser4_key key;
+       /* offset from start of a node measured in 8-byte chunks */
+       /* 24 */ d16 offset;
+       /* 26 */ d16 flags;
+       /* 28 */ d16 plugin_id;
+} PACKED item_header40;
+
+size_t item_overhead_node40(const znode * node, flow_t * aflow);
+size_t free_space_node40(znode * node);
+node_search_result lookup_node40(znode * node, const reiser4_key * key,
+                                lookup_bias bias, coord_t * coord);
+int num_of_items_node40(const znode * node);
+char *item_by_coord_node40(const coord_t * coord);
+int length_by_coord_node40(const coord_t * coord);
+item_plugin *plugin_by_coord_node40(const coord_t * coord);
+reiser4_key *key_at_node40(const coord_t * coord, reiser4_key * key);
+size_t estimate_node40(znode * node);
+int check_node40(const znode * node, __u32 flags, const char **error);
+int parse_node40(znode * node);
+int init_node40(znode * node);
+#ifdef GUESS_EXISTS
+int guess_node40(const znode * node);
+#endif
+void change_item_size_node40(coord_t * coord, int by);
+int create_item_node40(coord_t * target, const reiser4_key * key,
+                      reiser4_item_data * data, carry_plugin_info * info);
+void update_item_key_node40(coord_t * target, const reiser4_key * key,
+                           carry_plugin_info * info);
+int kill_node40(struct carry_kill_data *, carry_plugin_info *);
+int cut_node40(struct carry_cut_data *, carry_plugin_info *);
+int shift_node40(coord_t * from, znode * to, shift_direction pend,
+                /* if @from->node becomes
+                   empty - it will be deleted from
+                   the tree if this is set to 1
+                 */
+                int delete_child, int including_stop_coord,
+                carry_plugin_info * info);
+
+int fast_insert_node40(const coord_t * coord);
+int fast_paste_node40(const coord_t * coord);
+int fast_cut_node40(const coord_t * coord);
+int max_item_size_node40(void);
+int prepare_removal_node40(znode * empty, carry_plugin_info * info);
+int set_item_plugin_node40(coord_t * coord, item_id id);
+int shrink_item_node40(coord_t * coord, int delta);
+
+#if REISER4_DEBUG
+void *shift_check_prepare(const znode *left, const znode *right);
+void shift_check(void *vp, const znode *left, const znode *right);
+#endif
+
+/* __REISER4_NODE40_H__ */
+#endif
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/node/node.c linux-2.6.20/fs/reiser4/plugin/node/node.c
--- linux-2.6.20.orig/fs/reiser4/plugin/node/node.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/node/node.c  2007-05-06 14:50:43.835018219 +0400
@@ -0,0 +1,131 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Node plugin interface.
+
+   Description: The tree provides the abstraction of flows, which it
+   internally fragments into items which it stores in nodes.
+
+   A key_atom is a piece of data bound to a single key.
+
+   For reasonable space efficiency to be achieved it is often
+   necessary to store key_atoms in the nodes in the form of items, where
+   an item is a sequence of key_atoms of the same or similar type. It is
+   more space-efficient, because the item can implement (very)
+   efficient compression of key_atom's bodies using internal knowledge
+   about their semantics, and it can often avoid having a key for each
+   key_atom. Each type of item has specific operations implemented by its
+   item handler (see balance.c).
+
+   Rationale: the rest of the code (specifically balancing routines)
+   accesses leaf level nodes through this interface. This way we can
+   implement various block layouts and even combine various layouts
+   within the same tree. Balancing/allocating algorithms should not
+   care about peculiarities of splitting/merging specific item types,
+   but rather should leave that to the item's item handler.
+
+   Items, including those that provide the abstraction of flows, have
+   the property that if you move them in part or in whole to another
+   node, the balancing code invokes their is_left_mergeable()
+   item_operation to determine if they are mergeable with their new
+   neighbor in the node you have moved them to.  For some items the
+   is_left_mergeable() function always returns null.
+
+   When moving the bodies of items from one node to another:
+
+     if a partial item is shifted to another node the balancing code invokes
+     an item handler method to handle the item splitting.
+
+     if the balancing code needs to merge with an item in the node it
+     is shifting to, it will invoke an item handler method to handle
+     the item merging.
+
+     if it needs to move whole item bodies unchanged, the balancing code uses xmemcpy()
+     adjusting the item headers after the move is done using the node handler.
+*/
+
+#include "../../forward.h"
+#include "../../debug.h"
+#include "../../key.h"
+#include "../../coord.h"
+#include "../plugin_header.h"
+#include "../item/item.h"
+#include "node.h"
+#include "../plugin.h"
+#include "../../znode.h"
+#include "../../tree.h"
+#include "../../super.h"
+#include "../../reiser4.h"
+
+/**
+ * leftmost_key_in_node - get the smallest key in node
+ * @node:
+ * @key: store result here
+ *
+ * Stores the leftmost key of @node in @key.
+ */
+reiser4_key *leftmost_key_in_node(const znode *node, reiser4_key *key)
+{
+       assert("nikita-1634", node != NULL);
+       assert("nikita-1635", key != NULL);
+
+       if (!node_is_empty(node)) {
+               coord_t first_item;
+
+               coord_init_first_unit(&first_item, (znode *) node);
+               item_key_by_coord(&first_item, key);
+       } else
+               *key = *reiser4_max_key();
+       return key;
+}
+
+node_plugin node_plugins[LAST_NODE_ID] = {
+       [NODE40_ID] = {
+               .h = {
+                       .type_id = REISER4_NODE_PLUGIN_TYPE,
+                       .id = NODE40_ID,
+                       .pops = NULL,
+                       .label = "unified",
+                       .desc = "unified node layout",
+                       .linkage = {NULL, NULL}
+               },
+               .item_overhead = item_overhead_node40,
+               .free_space = free_space_node40,
+               .lookup = lookup_node40,
+               .num_of_items = num_of_items_node40,
+               .item_by_coord = item_by_coord_node40,
+               .length_by_coord = length_by_coord_node40,
+               .plugin_by_coord = plugin_by_coord_node40,
+               .key_at = key_at_node40,
+               .estimate = estimate_node40,
+               .check = check_node40,
+               .parse = parse_node40,
+               .init = init_node40,
+#ifdef GUESS_EXISTS
+               .guess = guess_node40,
+#endif
+               .change_item_size = change_item_size_node40,
+               .create_item = create_item_node40,
+               .update_item_key = update_item_key_node40,
+               .cut_and_kill = kill_node40,
+               .cut = cut_node40,
+               .shift = shift_node40,
+               .shrink_item = shrink_item_node40,
+               .fast_insert = fast_insert_node40,
+               .fast_paste = fast_paste_node40,
+               .fast_cut = fast_cut_node40,
+               .max_item_size = max_item_size_node40,
+               .prepare_removal = prepare_removal_node40,
+               .set_item_plugin = set_item_plugin_node40
+       }
+};
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/node/node.h linux-2.6.20/fs/reiser4/plugin/node/node.h
--- linux-2.6.20.orig/fs/reiser4/plugin/node/node.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/node/node.h  2007-05-06 14:50:43.835018219 +0400
@@ -0,0 +1,272 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* We need a definition of the default node layout here. */
+
+/* Generally speaking, it is best to have free space in the middle of the
+   node so that two sets of things can grow towards it, and to have the
+   item bodies on the left so that the last one of them grows into free
+   space.  We optimize for the case where we append new items to the end
+   of the node, or grow the last item, because it hurts nothing to so
+   optimize and it is a common special case to do massive insertions in
+   increasing key order (and one of cases more likely to have a real user
+   notice the delay time for).
+
+   formatted leaf default layout: (leaf1)
+
+   |node header:item bodies:free space:key + pluginid + item offset|
+
+   We grow towards the middle, optimizing layout for the case where we
+   append new items to the end of the node.  The node header is fixed
+   length.  Keys, and item offsets plus pluginids for the items
+   corresponding to them are in increasing key order, and are fixed
+   length.  Item offsets are relative to start of node (16 bits creating
+   a node size limit of 64k, 12 bits might be a better choice....).  Item
+   bodies are in decreasing key order.  Item bodies have a variable size.
+   There is a one to one to one mapping of keys to item offsets to item
+   bodies.  Item offsets consist of pointers to the zeroth byte of the
+   item body.  Item length equals the start of the next item minus the
+   start of this item, except the zeroth item whose length equals the end
+   of the node minus the start of that item (plus a byte).  In other
+   words, the item length is not recorded anywhere, and it does not need
+   to be since it is computable.
+
+   Leaf variable length items and keys layout : (lvar)
+
+   |node header:key offset + item offset + pluginid triplets:free space:key bodies:item bodies|
+
+   We grow towards the middle, optimizing layout for the case where we
+   append new items to the end of the node.  The node header is fixed
+   length.  Keys and item offsets for the items corresponding to them are
+   in increasing key order, and keys are variable length.  Item offsets
+   are relative to start of node (16 bits).  Item bodies are in
+   decreasing key order.  Item bodies have a variable size.  There is a
+   one to one to one mapping of keys to item offsets to item bodies.
+   Item offsets consist of pointers to the zeroth byte of the item body.
+   Item length equals the start of the next item's key minus the start of
+   this item, except the zeroth item whose length equals the end of the
+   node minus the start of that item (plus a byte).
+
+   leaf compressed keys layout: (lcomp)
+
+   |node header:key offset + key inherit + item offset pairs:free space:key bodies:item bodies|
+
+   We grow towards the middle, optimizing layout for the case where we
+   append new items to the end of the node.  The node header is fixed
+   length.  Keys and item offsets for the items corresponding to them are
+   in increasing key order, and keys are variable length.  The "key
+   inherit" field indicates how much of the key prefix is identical to
+   the previous key (stem compression as described in "Managing
+   Gigabytes" is used).  key_inherit is a one byte integer.  The
+   intra-node searches performed through this layout are linear searches,
+   and this is theorized to not hurt performance much due to the high
+   cost of processor stalls on modern CPUs, and the small number of keys
+   in a single node.  Item offsets are relative to start of node (16
+   bits).  Item bodies are in decreasing key order.  Item bodies have a
+   variable size.  There is a one to one to one mapping of keys to item
+   offsets to item bodies.  Item offsets consist of pointers to the
+   zeroth byte of the item body.  Item length equals the start of the
+   next item minus the start of this item, except the zeroth item whose
+   length equals the end of the node minus the start of that item (plus a
+   byte).  In other words, item length and key length is not recorded
+   anywhere, and it does not need to be since it is computable.
+
+   internal node default layout: (idef1)
+
+   just like ldef1 except that item bodies are either blocknrs of
+   children or extents, and moving them may require updating parent
+   pointers in the nodes that they point to.
+*/
+
+/* There is an inherent 3-way tradeoff between optimizing and
+   exchanging disks between different architectures and code
+   complexity.  This is optimal and simple and inexchangeable.
+   Someone else can do the code for exchanging disks and make it
+   complex. It would not be that hard.  Using other than the PAGE_SIZE
+   might be suboptimal.
+*/
+
+#if !defined( __REISER4_NODE_H__ )
+#define __REISER4_NODE_H__
+
+#define LEAF40_NODE_SIZE PAGE_CACHE_SIZE
+
+#include "../../dformat.h"
+#include "../plugin_header.h"
+
+#include <linux/types.h>
+
+typedef enum {
+       NS_FOUND = 0,
+       NS_NOT_FOUND = -ENOENT
+} node_search_result;
+
+/* Maximal possible space overhead for creation of new item in a node */
+#define REISER4_NODE_MAX_OVERHEAD ( sizeof( reiser4_key ) + 32 )
+
+typedef enum {
+       REISER4_NODE_DKEYS = (1 << 0),
+       REISER4_NODE_TREE_STABLE = (1 << 1)
+} reiser4_node_check_flag;
+
+/* cut and cut_and_kill have too long list of parameters. This structure is just to safe some space on stack */
+struct cut_list {
+       coord_t *from;
+       coord_t *to;
+       const reiser4_key *from_key;
+       const reiser4_key *to_key;
+       reiser4_key *smallest_removed;
+       carry_plugin_info *info;
+       __u32 flags;
+       struct inode *inode;    /* this is to pass list of eflushed jnodes down to extent_kill_hook */
+       lock_handle *left;
+       lock_handle *right;
+};
+
+struct carry_cut_data;
+struct carry_kill_data;
+
+/* The responsibility of the node plugin is to store and give access
+   to the sequence of items within the node.  */
+typedef struct node_plugin {
+       /* generic plugin fields */
+       plugin_header h;
+
+       /* calculates the amount of space that will be required to store an
+          item which is in addition to the space consumed by the item body.
+          (the space consumed by the item body can be gotten by calling
+          item->estimate) */
+        size_t(*item_overhead) (const znode * node, flow_t * f);
+
+       /* returns free space by looking into node (i.e., without using
+          znode->free_space). */
+        size_t(*free_space) (znode * node);
+       /* search within the node for the one item which might
+          contain the key, invoking item->search_within to search within
+          that item to see if it is in there */
+        node_search_result(*lookup) (znode * node, const reiser4_key * key,
+                                     lookup_bias bias, coord_t * coord);
+       /* number of items in node */
+       int (*num_of_items) (const znode * node);
+
+       /* store information about item in @coord in @data */
+       /* break into several node ops, don't add any more uses of this before doing so */
+       /*int ( *item_at )( const coord_t *coord, reiser4_item_data *data ); */
+       char *(*item_by_coord) (const coord_t * coord);
+       int (*length_by_coord) (const coord_t * coord);
+       item_plugin *(*plugin_by_coord) (const coord_t * coord);
+
+       /* store item key in @key */
+       reiser4_key *(*key_at) (const coord_t * coord, reiser4_key * key);
+       /* conservatively estimate whether unit of what size can fit
+          into node. This estimation should be performed without
+          actually looking into the node's content (free space is saved in
+          znode). */
+        size_t(*estimate) (znode * node);
+
+       /* performs every consistency check the node plugin author could
+          imagine. Optional. */
+       int (*check) (const znode * node, __u32 flags, const char **error);
+
+       /* Called when node is read into memory and node plugin is
+          already detected. This should read some data into znode (like free
+          space counter) and, optionally, check data consistency.
+        */
+       int (*parse) (znode * node);
+       /* This method is called on a new node to initialise plugin specific
+          data (header, etc.) */
+       int (*init) (znode * node);
+       /* Check whether @node content conforms to this plugin format.
+          Probably only useful after support for old V3.x formats is added.
+          Uncomment after 4.0 only.
+        */
+       /*      int ( *guess )( const znode *node ); */
+#if REISER4_DEBUG
+       void (*print) (const char *prefix, const znode * node, __u32 flags);
+#endif
+       /* change size of @item by @by bytes. @item->node has enough free
+          space. When @by > 0 - free space is appended to end of item. When
+          @by < 0 - item is truncated - it is assumed that last @by bytes if
+          the item are freed already */
+       void (*change_item_size) (coord_t * item, int by);
+
+       /* create new item @length bytes long in coord @target */
+       int (*create_item) (coord_t * target, const reiser4_key * key,
+                           reiser4_item_data * data, carry_plugin_info * info);
+
+       /* update key of item. */
+       void (*update_item_key) (coord_t * target, const reiser4_key * key,
+                                carry_plugin_info * info);
+
+       int (*cut_and_kill) (struct carry_kill_data *, carry_plugin_info *);
+       int (*cut) (struct carry_cut_data *, carry_plugin_info *);
+
+       /*
+        * shrink item pointed to by @coord by @delta bytes.
+        */
+       int (*shrink_item) (coord_t * coord, int delta);
+
+       /* copy as much as possible but not more than up to @stop from
+          @stop->node to @target. If (pend == append) then data from beginning of
+          @stop->node are copied to the end of @target. If (pend == prepend) then
+          data from the end of @stop->node are copied to the beginning of
+          @target. Copied data are removed from @stop->node. Information
+          about what to do on upper level is stored in @todo */
+       int (*shift) (coord_t * stop, znode * target, shift_direction pend,
+                     int delete_node, int including_insert_coord,
+                     carry_plugin_info * info);
+       /* return true if this node allows skip carry() in some situations
+          (see fs/reiser4/tree.c:insert_by_coord()). Reiser3.x format
+          emulation doesn't.
+
+          This will speedup insertions that doesn't require updates to the
+          parent, by bypassing initialisation of carry() structures. It's
+          believed that majority of insertions will fit there.
+
+        */
+       int (*fast_insert) (const coord_t * coord);
+       int (*fast_paste) (const coord_t * coord);
+       int (*fast_cut) (const coord_t * coord);
+       /* this limits max size of item which can be inserted into a node and
+          number of bytes item in a node may be appended with */
+       int (*max_item_size) (void);
+       int (*prepare_removal) (znode * empty, carry_plugin_info * info);
+       /* change plugin id of items which are in a node already. Currently it is Used in tail conversion for regular
+        * files */
+       int (*set_item_plugin) (coord_t * coord, item_id);
+} node_plugin;
+
+typedef enum {
+       /* standard unified node layout used for both leaf and internal
+          nodes */
+       NODE40_ID,
+       LAST_NODE_ID
+} reiser4_node_id;
+
+extern reiser4_key *leftmost_key_in_node(const znode * node, reiser4_key * key);
+#if REISER4_DEBUG
+extern void print_node_content(const char *prefix, const znode * node,
+                              __u32 flags);
+#endif
+
+extern void indent_znode(const znode * node);
+
+typedef struct common_node_header {
+       /*
+        * identifier of node plugin. Must be located at the very beginning of
+        * a node.
+        */
+       __le16 plugin_id;
+} common_node_header;
+
+/* __REISER4_NODE_H__ */
+#endif
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/object.c linux-2.6.20/fs/reiser4/plugin/object.c
--- linux-2.6.20.orig/fs/reiser4/plugin/object.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/object.c     2007-05-06 14:50:43.835018219 +0400
@@ -0,0 +1,516 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/*
+ * Examples of object plugins: file, directory, symlink, special file.
+ *
+ * Plugins associated with inode:
+ *
+ * Plugin of inode is plugin referenced by plugin-id field of on-disk
+ * stat-data. How we store this plugin in in-core inode is not
+ * important. Currently pointers are used, another variant is to store offsets
+ * and do array lookup on each access.
+ *
+ * Now, each inode has one selected plugin: object plugin that
+ * determines what type of file this object is: directory, regular etc.
+ *
+ * This main plugin can use other plugins that are thus subordinated to
+ * it. Directory instance of object plugin uses hash; regular file
+ * instance uses tail policy plugin.
+ *
+ * Object plugin is either taken from id in stat-data or guessed from
+ * i_mode bits. Once it is established we ask it to install its
+ * subordinate plugins, by looking again in stat-data or inheriting them
+ * from parent.
+ *
+ * How new inode is initialized during ->read_inode():
+ * 1 read stat-data and initialize inode fields: i_size, i_mode,
+ *   i_generation, capabilities etc.
+ * 2 read plugin id from stat data or try to guess plugin id
+ *   from inode->i_mode bits if plugin id is missing.
+ * 3 Call ->init_inode() method of stat-data plugin to initialise inode fields.
+ *
+ * NIKITA-FIXME-HANS: can you say a little about 1 being done before 3?  What
+ * if stat data does contain i_size, etc., due to it being an unusual plugin?
+ *
+ * 4 Call ->activate() method of object's plugin. Plugin is either read from
+ *    from stat-data or guessed from mode bits
+ * 5 Call ->inherit() method of object plugin to inherit as yet un initialized
+ *    plugins from parent.
+ *
+ * Easy induction proves that on last step all plugins of inode would be
+ * initialized.
+ *
+ * When creating new object:
+ * 1 obtain object plugin id (see next period)
+ * NIKITA-FIXME-HANS: period?
+ * 2 ->install() this plugin
+ * 3 ->inherit() the rest from the parent
+ *
+ * We need some examples of creating an object with default and non-default
+ * plugin ids.  Nikita, please create them.
+ */
+
+#include "../inode.h"
+
+static int _bugop(void)
+{
+       BUG_ON(1);
+       return 0;
+}
+
+#define bugop ((void *)_bugop)
+
+static int _dummyop(void)
+{
+       return 0;
+}
+
+#define dummyop ((void *)_dummyop)
+
+static int change_file(struct inode *inode,
+                      reiser4_plugin * plugin,
+                      pset_member memb)
+{
+       /* cannot change object plugin of already existing object */
+       if (memb == PSET_FILE)
+               return RETERR(-EINVAL);
+
+       /* Change PSET_CREATE */
+       return aset_set_unsafe(&reiser4_inode_data(inode)->pset, memb, plugin);
+}
+
+static reiser4_plugin_ops file_plugin_ops = {
+       .change = change_file
+};
+
+/*
+ * Definitions of object plugins.
+ */
+
+file_plugin file_plugins[LAST_FILE_PLUGIN_ID] = {
+       [UNIX_FILE_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_FILE_PLUGIN_TYPE,
+                       .id = UNIX_FILE_PLUGIN_ID,
+                       .groups = (1 << REISER4_REGULAR_FILE),
+                       .pops = &file_plugin_ops,
+                       .label = "reg",
+                       .desc = "regular file",
+                       .linkage = {NULL, NULL},
+               },
+               .inode_ops = {
+                       .permission = reiser4_permission_common,
+                       .setattr = setattr_unix_file,
+                       .getattr = reiser4_getattr_common
+               },
+               .file_ops = {
+                       .llseek = generic_file_llseek,
+                       .read = read_unix_file,
+                       .write = write_unix_file,
+                       .aio_read = generic_file_aio_read,
+                       .ioctl = ioctl_unix_file,
+                       .mmap = mmap_unix_file,
+                       .open = open_unix_file,
+                       .release = release_unix_file,
+                       .fsync = sync_unix_file,
+                       .sendfile = sendfile_unix_file
+               },
+               .as_ops = {
+                       .writepage = reiser4_writepage,
+                       .readpage = readpage_unix_file,
+                       .sync_page = block_sync_page,
+                       .writepages = writepages_unix_file,
+                       .set_page_dirty = reiser4_set_page_dirty,
+                       .readpages = readpages_unix_file,
+                       .prepare_write = prepare_write_unix_file,
+                       .commit_write = commit_write_unix_file,
+                       .bmap = bmap_unix_file,
+                       .invalidatepage = reiser4_invalidatepage,
+                       .releasepage = reiser4_releasepage
+               },
+               .write_sd_by_inode = write_sd_by_inode_common,
+               .flow_by_inode = flow_by_inode_unix_file,
+               .key_by_inode = key_by_inode_and_offset_common,
+               .set_plug_in_inode = set_plug_in_inode_common,
+               .adjust_to_parent = adjust_to_parent_common,
+               .create_object = reiser4_create_object_common,
+               .delete_object = delete_object_unix_file,
+               .add_link = reiser4_add_link_common,
+               .rem_link = reiser4_rem_link_common,
+               .owns_item = owns_item_unix_file,
+               .can_add_link = can_add_link_common,
+               .detach = dummyop,
+               .bind = dummyop,
+               .safelink = safelink_common,
+               .estimate = {
+                       .create = estimate_create_common,
+                       .update = estimate_update_common,
+                       .unlink = estimate_unlink_common
+               },
+               .init_inode_data = init_inode_data_unix_file,
+               .cut_tree_worker = cut_tree_worker_common,
+               .wire = {
+                       .write = wire_write_common,
+                       .read = wire_read_common,
+                       .get = wire_get_common,
+                       .size = wire_size_common,
+                       .done = wire_done_common
+               }
+       },
+       [DIRECTORY_FILE_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_FILE_PLUGIN_TYPE,
+                       .id = DIRECTORY_FILE_PLUGIN_ID,
+                       .groups = (1 << REISER4_DIRECTORY_FILE),
+                       .pops = &file_plugin_ops,
+                       .label = "dir",
+                       .desc = "directory",
+                       .linkage = {NULL, NULL}
+               },
+               .inode_ops = {.create = NULL},
+               .file_ops = {.owner = NULL},
+               .as_ops = {.writepage = NULL},
+
+               .write_sd_by_inode = write_sd_by_inode_common,
+               .flow_by_inode = bugop,
+               .key_by_inode = bugop,
+               .set_plug_in_inode = set_plug_in_inode_common,
+               .adjust_to_parent = adjust_to_parent_common_dir,
+               .create_object = reiser4_create_object_common,
+               .delete_object = reiser4_delete_dir_common,
+               .add_link = reiser4_add_link_common,
+               .rem_link = rem_link_common_dir,
+               .owns_item = owns_item_common_dir,
+               .can_add_link = can_add_link_common,
+               .can_rem_link = can_rem_link_common_dir,
+               .detach = reiser4_detach_common_dir,
+               .bind = reiser4_bind_common_dir,
+               .safelink = safelink_common,
+               .estimate = {
+                       .create = estimate_create_common_dir,
+                       .update = estimate_update_common,
+                       .unlink = estimate_unlink_common_dir
+               },
+               .wire = {
+                       .write = wire_write_common,
+                       .read = wire_read_common,
+                       .get = wire_get_common,
+                       .size = wire_size_common,
+                       .done = wire_done_common
+               },
+               .init_inode_data = init_inode_ordering,
+               .cut_tree_worker = cut_tree_worker_common,
+       },
+       [SYMLINK_FILE_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_FILE_PLUGIN_TYPE,
+                       .id = SYMLINK_FILE_PLUGIN_ID,
+                       .groups = (1 << REISER4_SYMLINK_FILE),
+                       .pops = &file_plugin_ops,
+                       .label = "symlink",
+                       .desc = "symbolic link",
+                       .linkage = {NULL,NULL}
+               },
+               .inode_ops = {
+                       .readlink = generic_readlink,
+                       .follow_link = reiser4_follow_link_common,
+                       .permission = reiser4_permission_common,
+                       .setattr = reiser4_setattr_common,
+                       .getattr = reiser4_getattr_common
+               },
+               /* inode->i_fop of symlink is initialized by NULL in setup_inode_ops */
+               .file_ops = {.owner = NULL},
+               .as_ops = {.writepage = NULL},
+
+               .write_sd_by_inode = write_sd_by_inode_common,
+               .set_plug_in_inode = set_plug_in_inode_common,
+               .adjust_to_parent = adjust_to_parent_common,
+               .create_object = reiser4_create_symlink,
+               .delete_object = reiser4_delete_object_common,
+               .add_link = reiser4_add_link_common,
+               .rem_link = reiser4_rem_link_common,
+               .can_add_link = can_add_link_common,
+               .detach = dummyop,
+               .bind = dummyop,
+               .safelink = safelink_common,
+               .estimate = {
+                       .create = estimate_create_common,
+                       .update = estimate_update_common,
+                       .unlink = estimate_unlink_common
+               },
+               .init_inode_data = init_inode_ordering,
+               .cut_tree_worker = cut_tree_worker_common,
+               .destroy_inode = destroy_inode_symlink,
+               .wire = {
+                       .write = wire_write_common,
+                       .read = wire_read_common,
+                       .get = wire_get_common,
+                       .size = wire_size_common,
+                       .done = wire_done_common
+               }
+       },
+       [SPECIAL_FILE_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_FILE_PLUGIN_TYPE,
+                       .id = SPECIAL_FILE_PLUGIN_ID,
+                       .groups = (1 << REISER4_SPECIAL_FILE),
+                       .pops = &file_plugin_ops,
+                       .label = "special",
+                       .desc =
+                       "special: fifo, device or socket",
+                       .linkage = {NULL, NULL}
+               },
+               .inode_ops = {
+                       .permission = reiser4_permission_common,
+                       .setattr = reiser4_setattr_common,
+                       .getattr = reiser4_getattr_common
+               },
+               /* file_ops of special files (sockets, block, char, fifo) are
+                  initialized by init_special_inode. */
+               .file_ops = {.owner = NULL},
+               .as_ops = {.writepage = NULL},
+
+               .write_sd_by_inode = write_sd_by_inode_common,
+               .set_plug_in_inode = set_plug_in_inode_common,
+               .adjust_to_parent = adjust_to_parent_common,
+               .create_object = reiser4_create_object_common,
+               .delete_object = reiser4_delete_object_common,
+               .add_link = reiser4_add_link_common,
+               .rem_link = reiser4_rem_link_common,
+               .owns_item = owns_item_common,
+               .can_add_link = can_add_link_common,
+               .detach = dummyop,
+               .bind = dummyop,
+               .safelink = safelink_common,
+               .estimate = {
+                       .create = estimate_create_common,
+                       .update = estimate_update_common,
+                       .unlink = estimate_unlink_common
+               },
+               .init_inode_data = init_inode_ordering,
+               .cut_tree_worker = cut_tree_worker_common,
+               .wire = {
+                       .write = wire_write_common,
+                       .read = wire_read_common,
+                       .get = wire_get_common,
+                       .size = wire_size_common,
+                       .done = wire_done_common
+               }
+       },
+       [CRYPTCOMPRESS_FILE_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_FILE_PLUGIN_TYPE,
+                       .id = CRYPTCOMPRESS_FILE_PLUGIN_ID,
+                       .groups = (1 << REISER4_REGULAR_FILE),
+                       .pops = &file_plugin_ops,
+                       .label = "cryptcompress",
+                       .desc = "cryptcompress file",
+                       .linkage = {NULL, NULL}
+               },
+               .inode_ops = {
+                       .permission = reiser4_permission_common,
+                       .setattr = prot_setattr_cryptcompress,
+                       .getattr = reiser4_getattr_common
+               },
+               .file_ops = {
+                       .llseek = generic_file_llseek,
+                       .read = prot_read_cryptcompress,
+                       .write = prot_write_cryptcompress,
+                       .aio_read = generic_file_aio_read,
+                       .mmap = prot_mmap_cryptcompress,
+                       .release = prot_release_cryptcompress,
+                       .fsync = reiser4_sync_common,
+                       .sendfile = prot_sendfile_cryptcompress
+               },
+               .as_ops = {
+                       .writepage = reiser4_writepage,
+                       .readpage = readpage_cryptcompress,
+                       .sync_page = block_sync_page,
+                       .writepages = writepages_cryptcompress,
+                       .set_page_dirty = reiser4_set_page_dirty,
+                       .readpages = readpages_cryptcompress,
+                       .prepare_write = prepare_write_common,
+                       .invalidatepage = reiser4_invalidatepage,
+                       .releasepage = reiser4_releasepage
+               },
+               .write_sd_by_inode = write_sd_by_inode_common,
+               .flow_by_inode = flow_by_inode_cryptcompress,
+               .key_by_inode = key_by_inode_cryptcompress,
+               .set_plug_in_inode = set_plug_in_inode_common,
+               .adjust_to_parent = adjust_to_parent_cryptcompress,
+               .create_object = create_cryptcompress,
+               .open_object = open_object_cryptcompress,
+               .delete_object = delete_object_cryptcompress,
+               .add_link = reiser4_add_link_common,
+               .rem_link = reiser4_rem_link_common,
+               .owns_item = owns_item_common,
+               .can_add_link = can_add_link_common,
+               .detach = dummyop,
+               .bind = dummyop,
+               .safelink = safelink_common,
+               .estimate = {
+                       .create = estimate_create_common,
+                       .update = estimate_update_common,
+                       .unlink = estimate_unlink_common
+               },
+               .init_inode_data = init_inode_data_cryptcompress,
+               .cut_tree_worker = cut_tree_worker_cryptcompress,
+               .destroy_inode = destroy_inode_cryptcompress,
+               .wire = {
+                       .write = wire_write_common,
+                       .read = wire_read_common,
+                       .get = wire_get_common,
+                       .size = wire_size_common,
+                       .done = wire_done_common
+               }
+       }
+};
+
+static int change_dir(struct inode *inode,
+                     reiser4_plugin * plugin,
+                     pset_member memb)
+{
+       /* cannot change dir plugin of already existing object */
+       return RETERR(-EINVAL);
+}
+
+static reiser4_plugin_ops dir_plugin_ops = {
+       .change = change_dir
+};
+
+/*
+ * definition of directory plugins
+ */
+
+dir_plugin dir_plugins[LAST_DIR_ID] = {
+       /* standard hashed directory plugin */
+       [HASHED_DIR_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_DIR_PLUGIN_TYPE,
+                       .id = HASHED_DIR_PLUGIN_ID,
+                       .pops = &dir_plugin_ops,
+                       .label = "dir",
+                       .desc = "hashed directory",
+                       .linkage = {NULL, NULL}
+               },
+               .inode_ops = {
+                       .create = reiser4_create_common,
+                       .lookup = reiser4_lookup_common,
+                       .link = reiser4_link_common,
+                       .unlink = reiser4_unlink_common,
+                       .symlink = reiser4_symlink_common,
+                       .mkdir = reiser4_mkdir_common,
+                       .rmdir = reiser4_unlink_common,
+                       .mknod = reiser4_mknod_common,
+                       .rename = reiser4_rename_common,
+                       .permission = reiser4_permission_common,
+                       .setattr = reiser4_setattr_common,
+                       .getattr = reiser4_getattr_common
+               },
+               .file_ops = {
+                       .llseek = reiser4_llseek_dir_common,
+                       .read = generic_read_dir,
+                       .readdir = reiser4_readdir_common,
+                       .release = reiser4_release_dir_common,
+                       .fsync = reiser4_sync_common
+               },
+               .as_ops = {
+                       .writepage = bugop,
+                       .sync_page = bugop,
+                       .writepages = dummyop,
+                       .set_page_dirty = bugop,
+                       .readpages = bugop,
+                       .prepare_write = bugop,
+                       .commit_write = bugop,
+                       .bmap = bugop,
+                       .invalidatepage = bugop,
+                       .releasepage = bugop
+               },
+               .get_parent = get_parent_common,
+               .is_name_acceptable = is_name_acceptable_common,
+               .build_entry_key = build_entry_key_hashed,
+               .build_readdir_key = build_readdir_key_common,
+               .add_entry = reiser4_add_entry_common,
+               .rem_entry = reiser4_rem_entry_common,
+               .init = reiser4_dir_init_common,
+               .done = reiser4_dir_done_common,
+               .attach = reiser4_attach_common,
+               .detach = reiser4_detach_common,
+               .estimate = {
+                       .add_entry = estimate_add_entry_common,
+                       .rem_entry = estimate_rem_entry_common,
+                       .unlink = dir_estimate_unlink_common
+               }
+       },
+       /* hashed directory for which seekdir/telldir are guaranteed to
+        * work. Brain-damage. */
+       [SEEKABLE_HASHED_DIR_PLUGIN_ID] = {
+               .h = {
+                       .type_id = REISER4_DIR_PLUGIN_TYPE,
+                       .id = SEEKABLE_HASHED_DIR_PLUGIN_ID,
+                       .pops = &dir_plugin_ops,
+                       .label = "dir32",
+                       .desc = "directory hashed with 31 bit hash",
+                       .linkage = {NULL, NULL}
+               },
+               .inode_ops = {
+                       .create = reiser4_create_common,
+                       .lookup = reiser4_lookup_common,
+                       .link = reiser4_link_common,
+                       .unlink = reiser4_unlink_common,
+                       .symlink = reiser4_symlink_common,
+                       .mkdir = reiser4_mkdir_common,
+                       .rmdir = reiser4_unlink_common,
+                       .mknod = reiser4_mknod_common,
+                       .rename = reiser4_rename_common,
+                       .permission = reiser4_permission_common,
+                       .setattr = reiser4_setattr_common,
+                       .getattr = reiser4_getattr_common
+               },
+               .file_ops = {
+                       .llseek = reiser4_llseek_dir_common,
+                       .read = generic_read_dir,
+                       .readdir = reiser4_readdir_common,
+                       .release = reiser4_release_dir_common,
+                       .fsync = reiser4_sync_common
+               },
+               .as_ops = {
+                       .writepage = bugop,
+                       .sync_page = bugop,
+                       .writepages = dummyop,
+                       .set_page_dirty = bugop,
+                       .readpages = bugop,
+                       .prepare_write = bugop,
+                       .commit_write = bugop,
+                       .bmap = bugop,
+                       .invalidatepage = bugop,
+                       .releasepage = bugop
+               },
+               .get_parent = get_parent_common,
+               .is_name_acceptable = is_name_acceptable_common,
+               .build_entry_key = build_entry_key_seekable,
+               .build_readdir_key = build_readdir_key_common,
+               .add_entry = reiser4_add_entry_common,
+               .rem_entry = reiser4_rem_entry_common,
+               .init = reiser4_dir_init_common,
+               .done = reiser4_dir_done_common,
+               .attach = reiser4_attach_common,
+               .detach = reiser4_detach_common,
+               .estimate = {
+                       .add_entry = estimate_add_entry_common,
+                       .rem_entry = estimate_rem_entry_common,
+                       .unlink = dir_estimate_unlink_common
+               }
+       }
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/object.h linux-2.6.20/fs/reiser4/plugin/object.h
--- linux-2.6.20.orig/fs/reiser4/plugin/object.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/object.h     2007-05-06 14:50:43.839019469 +0400
@@ -0,0 +1,121 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Declaration of object plugin functions. */
+
+#if !defined( __FS_REISER4_PLUGIN_OBJECT_H__ )
+#define __FS_REISER4_PLUGIN_OBJECT_H__
+
+#include "../type_safe_hash.h"
+
+/* common implementations of inode operations */
+int reiser4_create_common(struct inode *parent, struct dentry *dentry,
+                         int mode, struct nameidata *);
+struct dentry * reiser4_lookup_common(struct inode *parent,
+                                     struct dentry *dentry,
+                                     struct nameidata *nameidata);
+int reiser4_link_common(struct dentry *existing, struct inode *parent,
+                       struct dentry *newname);
+int reiser4_unlink_common(struct inode *parent, struct dentry *victim);
+int reiser4_mkdir_common(struct inode *parent, struct dentry *dentry, int mode);
+int reiser4_symlink_common(struct inode *parent, struct dentry *dentry,
+                  const char *linkname);
+int reiser4_mknod_common(struct inode *parent, struct dentry *dentry,
+                int mode, dev_t rdev);
+int reiser4_rename_common(struct inode *old_dir, struct dentry *old_name,
+                         struct inode *new_dir, struct dentry *new_name);
+void *reiser4_follow_link_common(struct dentry *, struct nameidata *data);
+int reiser4_permission_common(struct inode *, int mask,
+                             struct nameidata *nameidata);
+int reiser4_setattr_common(struct dentry *, struct iattr *);
+int reiser4_getattr_common(struct vfsmount *mnt, struct dentry *,
+                          struct kstat *);
+
+/* common implementations of file operations */
+loff_t reiser4_llseek_dir_common(struct file *, loff_t off, int origin);
+int reiser4_readdir_common(struct file *, void *dirent, filldir_t);
+int reiser4_release_dir_common(struct inode *, struct file *);
+int reiser4_sync_common(struct file *, struct dentry *, int datasync);
+
+/* common implementations of address space operations */
+int prepare_write_common(struct file *, struct page *, unsigned from,
+                        unsigned to);
+
+/* file plugin operations: common implementations */
+int write_sd_by_inode_common(struct inode *);
+int key_by_inode_and_offset_common(struct inode *, loff_t, reiser4_key *);
+int set_plug_in_inode_common(struct inode *object, struct inode *parent,
+                            reiser4_object_create_data *);
+int adjust_to_parent_common(struct inode *object, struct inode *parent,
+                           struct inode *root);
+int adjust_to_parent_common_dir(struct inode *object, struct inode *parent,
+                               struct inode *root);
+int adjust_to_parent_cryptcompress(struct inode *object, struct inode *parent,
+                                  struct inode *root);
+int reiser4_create_object_common(struct inode *object, struct inode *parent,
+                                reiser4_object_create_data *);
+int reiser4_delete_object_common(struct inode *);
+int reiser4_delete_dir_common(struct inode *);
+int reiser4_add_link_common(struct inode *object, struct inode *parent);
+int reiser4_rem_link_common(struct inode *object, struct inode *parent);
+int rem_link_common_dir(struct inode *object, struct inode *parent);
+int owns_item_common(const struct inode *, const coord_t *);
+int owns_item_common_dir(const struct inode *, const coord_t *);
+int can_add_link_common(const struct inode *);
+int can_rem_link_common_dir(const struct inode *);
+int reiser4_detach_common_dir(struct inode *child, struct inode *parent);
+int reiser4_bind_common_dir(struct inode *child, struct inode *parent);
+int safelink_common(struct inode *, reiser4_safe_link_t, __u64 value);
+reiser4_block_nr estimate_create_common(const struct inode *);
+reiser4_block_nr estimate_create_common_dir(const struct inode *);
+reiser4_block_nr estimate_update_common(const struct inode *);
+reiser4_block_nr estimate_unlink_common(const struct inode *,
+                                       const struct inode *);
+reiser4_block_nr estimate_unlink_common_dir(const struct inode *,
+                                           const struct inode *);
+char *wire_write_common(struct inode *, char *start);
+char *wire_read_common(char *addr, reiser4_object_on_wire *);
+struct dentry *wire_get_common(struct super_block *, reiser4_object_on_wire *);
+int wire_size_common(struct inode *);
+void wire_done_common(reiser4_object_on_wire *);
+
+/* dir plugin operations: common implementations */
+struct dentry *get_parent_common(struct inode *child);
+int is_name_acceptable_common(const struct inode *, const char *name, int len);
+void build_entry_key_common(const struct inode *,
+                           const struct qstr *qname, reiser4_key *);
+int build_readdir_key_common(struct file *dir, reiser4_key *);
+int reiser4_add_entry_common(struct inode *object, struct dentry *where,
+                    reiser4_object_create_data *, reiser4_dir_entry_desc *);
+int reiser4_rem_entry_common(struct inode *object, struct dentry *where,
+                    reiser4_dir_entry_desc *);
+int reiser4_dir_init_common(struct inode *object, struct inode *parent,
+                           reiser4_object_create_data *);
+int reiser4_dir_done_common(struct inode *);
+int reiser4_attach_common(struct inode *child, struct inode *parent);
+int reiser4_detach_common(struct inode *object, struct inode *parent);
+reiser4_block_nr estimate_add_entry_common(const struct inode *);
+reiser4_block_nr estimate_rem_entry_common(const struct inode *);
+reiser4_block_nr dir_estimate_unlink_common(const struct inode *,
+                                           const struct inode *);
+
+/* these are essential parts of common implementations, they are to make
+   customized implementations easier */
+int do_prepare_write(struct file *, struct page *, unsigned from, unsigned to);
+
+/* merely useful functions */
+int lookup_sd(struct inode *, znode_lock_mode, coord_t *, lock_handle *,
+             const reiser4_key *, int silent);
+
+/* __FS_REISER4_PLUGIN_OBJECT_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/plugin.c linux-2.6.20/fs/reiser4/plugin/plugin.c
--- linux-2.6.20.orig/fs/reiser4/plugin/plugin.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/plugin.c     2007-05-06 14:50:43.839019469 +0400
@@ -0,0 +1,578 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Basic plugin infrastructure, lookup etc. */
+
+/* PLUGINS:
+
+   Plugins are internal Reiser4 "modules" or "objects" used to increase
+   extensibility and allow external users to easily adapt reiser4 to
+   their needs.
+
+   Plugins are classified into several disjoint "types". Plugins
+   belonging to the particular plugin type are termed "instances" of
+   this type. Currently the following types are present:
+
+    . object plugin
+    . hash plugin
+    . tail plugin
+    . perm plugin
+    . item plugin
+    . node layout plugin
+
+NIKITA-FIXME-HANS: update this list, and review this entire comment for currency
+
+   Object (file) plugin determines how given file-system object serves
+   standard VFS requests for read, write, seek, mmap etc. Instances of
+   file plugins are: regular file, directory, symlink. Another example
+   of file plugin is audit plugin, that optionally records accesses to
+   underlying object and forwards requests to it.
+
+   Hash plugins compute hashes used by reiser4 to store and locate
+   files within directories. Instances of hash plugin type are: r5,
+   tea, rupasov.
+
+   Tail plugins (or, more precisely, tail policy plugins) determine
+   when last part of the file should be stored in a formatted item.
+
+   Perm plugins control permissions granted for a process accessing a file.
+
+   Scope and lookup:
+
+   label such that pair ( type_label, plugin_label ) is unique.  This
+   pair is a globally persistent and user-visible plugin
+   identifier. Internally kernel maintains plugins and plugin types in
+   arrays using an index into those arrays as plugin and plugin type
+   identifiers. File-system in turn, also maintains persistent
+   "dictionary" which is mapping from plugin label to numerical
+   identifier which is stored in file-system objects.  That is, we
+   store the offset into the plugin array for that plugin type as the
+   plugin id in the stat data of the filesystem object.
+
+   plugin_labels have meaning for the user interface that assigns
+   plugins to files, and may someday have meaning for dynamic loading of
+   plugins and for copying of plugins from one fs instance to
+   another by utilities like cp and tar.
+
+   Internal kernel plugin type identifier (index in plugins[] array) is
+   of type reiser4_plugin_type. Set of available plugin types is
+   currently static, but dynamic loading doesn't seem to pose
+   insurmountable problems.
+
+   Within each type plugins are addressed by the identifiers of type
+   reiser4_plugin_id (indices in
+   reiser4_plugin_type_data.builtin[]). Such identifiers are only
+   required to be unique within one type, not globally.
+
+   Thus, plugin in memory is uniquely identified by the pair (type_id,
+   id).
+
+   Usage:
+
+   There exists only one instance of each plugin instance, but this
+   single instance can be associated with many entities (file-system
+   objects, items, nodes, transactions, file-descriptors etc.). Entity
+   to which plugin of given type is termed (due to the lack of
+   imagination) "subject" of this plugin type and, by abuse of
+   terminology, subject of particular instance of this type to which
+   it's attached currently. For example, inode is subject of object
+   plugin type. Inode representing directory is subject of directory
+   plugin, hash plugin type and some particular instance of hash plugin
+   type. Inode, representing regular file is subject of "regular file"
+   plugin, tail-policy plugin type etc.
+
+   With each subject the plugin possibly stores some state. For example,
+   the state of a directory plugin (instance of object plugin type) is pointer
+   to hash plugin (if directories always use hashing that is). State of
+   audit plugin is file descriptor (struct file) of log file or some
+   magic value to do logging through printk().
+
+   Interface:
+
+   In addition to a scalar identifier, each plugin type and plugin
+   proper has a "label": short string and a "description"---longer
+   descriptive string. Labels and descriptions of plugin types are
+   hard-coded into plugins[] array, declared and defined in
+   plugin.c. Label and description of plugin are stored in .label and
+   .desc fields of reiser4_plugin_header respectively. It's possible to
+   locate plugin by the pair of labels.
+
+   Features:
+
+    . user-level plugin manipulations:
+      + reiser4("filename/..file_plugin<='audit'");
+      + write(open("filename/..file_plugin"), "audit", 8);
+
+    . user level utilities lsplug and chplug to manipulate plugins.
+      Utilities are not of primary priority. Possibly they will be not
+      working on v4.0
+
+NIKITA-FIXME-HANS: this should be a mkreiserfs option not a mount option, do you agree?  I don't think that specifying it at mount time, and then changing it with each mount, is a good model for usage.
+
+    . mount option "plug" to set-up plugins of root-directory.
+      "plug=foo:bar" will set "bar" as default plugin of type "foo".
+
+   Limitations:
+
+    . each plugin type has to provide at least one builtin
+      plugin. This is technical limitation and it can be lifted in the
+      future.
+
+   TODO:
+
+   New plugin types/plugings:
+   Things we should be able to separately choose to inherit:
+
+   security plugins
+
+   stat data
+
+   file bodies
+
+   file plugins
+
+   dir plugins
+
+    . perm:acl
+
+    d audi---audit plugin intercepting and possibly logging all
+      accesses to object. Requires to put stub functions in file_operations
+      in stead of generic_file_*.
+
+NIKITA-FIXME-HANS: why make overflows a plugin?
+    . over---handle hash overflows
+
+    . sqnt---handle different access patterns and instruments read-ahead
+
+NIKITA-FIXME-HANS: describe the line below in more detail.
+
+    . hier---handle inheritance of plugins along file-system hierarchy
+
+   Different kinds of inheritance: on creation vs. on access.
+   Compatible/incompatible plugins.
+   Inheritance for multi-linked files.
+   Layered plugins.
+   Notion of plugin context is abandoned.
+
+Each file is associated
+   with one plugin and dependant plugins (hash, etc.) are stored as
+   main plugin state. Now, if we have plugins used for regular files
+   but not for directories, how such plugins would be inherited?
+    . always store them with directories also
+
+NIKTIA-FIXME-HANS: Do the line above.  It is not exclusive of doing the line below which is also useful.
+
+    . use inheritance hierarchy, independent of file-system namespace
+
+*/
+
+#include "../debug.h"
+#include "../dformat.h"
+#include "plugin_header.h"
+#include "item/static_stat.h"
+#include "node/node.h"
+#include "security/perm.h"
+#include "space/space_allocator.h"
+#include "disk_format/disk_format.h"
+#include "plugin.h"
+#include "../reiser4.h"
+#include "../jnode.h"
+#include "../inode.h"
+
+#include <linux/fs.h>          /* for struct super_block  */
+
+/* public interface */
+
+/* initialise plugin sub-system. Just call this once on reiser4 startup. */
+int init_plugins(void);
+int setup_plugins(struct super_block *super, reiser4_plugin ** area);
+int locate_plugin(struct inode *inode, plugin_locator * loc);
+
+/**
+ * init_plugins - initialize plugins
+ *
+ * Initializes plugin sub-system. It is part of reiser4 module
+ * initialization. For each plugin of each type init method is called and each
+ * plugin is put into list of plugins.
+ */
+int init_plugins(void)
+{
+       reiser4_plugin_type type_id;
+
+       for (type_id = 0; type_id < REISER4_PLUGIN_TYPES; ++type_id) {
+               reiser4_plugin_type_data *ptype;
+               int i;
+
+               ptype = &plugins[type_id];
+               assert("nikita-3508", ptype->label != NULL);
+               assert("nikita-3509", ptype->type_id == type_id);
+
+               INIT_LIST_HEAD(&ptype->plugins_list);
+/* NIKITA-FIXME-HANS: change builtin_num to some other name lacking the term builtin. */
+               for (i = 0; i < ptype->builtin_num; ++i) {
+                       reiser4_plugin *plugin;
+
+                       plugin = plugin_at(ptype, i);
+
+                       if (plugin->h.label == NULL)
+                               /* uninitialized slot encountered */
+                               continue;
+                       assert("nikita-3445", plugin->h.type_id == type_id);
+                       plugin->h.id = i;
+                       if (plugin->h.pops != NULL &&
+                           plugin->h.pops->init != NULL) {
+                               int result;
+
+                               result = plugin->h.pops->init(plugin);
+                               if (result != 0)
+                                       return result;
+                       }
+                       INIT_LIST_HEAD(&plugin->h.linkage);
+                       list_add_tail(&plugin->h.linkage, &ptype->plugins_list);
+               }
+       }
+       return 0;
+}
+
+/* true if plugin type id is valid */
+int is_plugin_type_valid(reiser4_plugin_type type)
+{
+       /* "type" is unsigned, so no comparison with 0 is
+          necessary */
+       return (type < REISER4_PLUGIN_TYPES);
+}
+
+/* true if plugin id is valid */
+int is_plugin_id_valid(reiser4_plugin_type type, reiser4_plugin_id id)
+{
+       assert("nikita-1653", is_plugin_type_valid(type));
+       return id < plugins[type].builtin_num;
+}
+
+/* return plugin by its @type and @id.
+
+   Both arguments are checked for validness: this is supposed to be called
+   from user-level.
+
+NIKITA-FIXME-HANS: Do you instead mean that this checks ids created in
+user space, and passed to the filesystem by use of method files? Your
+comment really confused me on the first reading....
+
+*/
+reiser4_plugin *plugin_by_unsafe_id(reiser4_plugin_type type /* plugin type
+                                                                * unchecked */,
+                                   reiser4_plugin_id id        /* plugin id,
+                                                                * unchecked */)
+{
+       if (is_plugin_type_valid(type)) {
+               if (is_plugin_id_valid(type, id))
+                       return plugin_at(&plugins[type], id);
+               else
+                       /* id out of bounds */
+                       warning("nikita-2913",
+                               "Invalid plugin id: [%i:%i]", type, id);
+       } else
+               /* type_id out of bounds */
+               warning("nikita-2914", "Invalid type_id: %i", type);
+       return NULL;
+}
+
+/**
+ * save_plugin_id - store plugin id in disk format
+ * @plugin: plugin to convert
+ * @area: where to store result
+ *
+ * Puts id of @plugin in little endian format to address @area.
+ */
+int save_plugin_id(reiser4_plugin *plugin /* plugin to convert */ ,
+                  d16 *area /* where to store result */ )
+{
+       assert("nikita-1261", plugin != NULL);
+       assert("nikita-1262", area != NULL);
+
+       put_unaligned(cpu_to_le16(plugin->h.id), area);
+       return 0;
+}
+
+/* list of all plugins of given type */
+struct list_head *get_plugin_list(reiser4_plugin_type type)
+{
+       assert("nikita-1056", is_plugin_type_valid(type));
+       return &plugins[type].plugins_list;
+}
+
+static void update_pset_mask(reiser4_inode * info, pset_member memb)
+{
+       struct dentry *rootdir;
+       reiser4_inode *root;
+
+       assert("edward-1443", memb != PSET_FILE);
+
+       rootdir = inode_by_reiser4_inode(info)->i_sb->s_root;
+       if (rootdir != NULL) {
+               root = reiser4_inode_data(rootdir->d_inode);
+               /*
+                * if inode is different from the default one, or we are
+                * changing plugin of root directory, update plugin_mask
+                */
+               if (aset_get(info->pset, memb) !=
+                   aset_get(root->pset, memb) ||
+                   info == root)
+                       info->plugin_mask |= (1 << memb);
+               else
+                       info->plugin_mask &= ~(1 << memb);
+       }
+}
+
+/* Get specified plugin set member from parent,
+   or from fs-defaults (if no parent is given) and
+   install the result to pset of @self */
+int grab_plugin_pset(struct inode *self,
+                    struct inode *ancestor,
+                    pset_member memb)
+{
+       reiser4_plugin *plug;
+       reiser4_inode *info;
+       int result = 0;
+
+       /* Do not grab if initialised already. */
+       info = reiser4_inode_data(self);
+       if (aset_get(info->pset, memb) != NULL)
+               return 0;
+       if (ancestor) {
+               reiser4_inode *parent;
+
+               parent = reiser4_inode_data(ancestor);
+               plug = aset_get(parent->hset, memb) ? :
+                       aset_get(parent->pset, memb);
+       }
+       else
+               plug = get_default_plugin(memb);
+
+       result = set_plugin(&info->pset, memb, plug);
+       if (result == 0) {
+               if (!ancestor || self->i_sb->s_root->d_inode != self)
+                       update_pset_mask(info, memb);
+       }
+       return result;
+}
+
+/* Take missing pset members from root inode */
+int finish_pset(struct inode *inode)
+{
+       reiser4_plugin *plug;
+       reiser4_inode *root;
+       reiser4_inode *info;
+       pset_member memb;
+       int result = 0;
+
+       root = reiser4_inode_data(inode->i_sb->s_root->d_inode);
+       info = reiser4_inode_data(inode);
+
+       assert("edward-1455", root != NULL);
+       assert("edward-1456", info != NULL);
+
+       /* file and directory plugins are already initialized. */
+       for (memb = PSET_DIR + 1; memb < PSET_LAST; ++memb) {
+
+               /* Do not grab if initialised already. */
+               if (aset_get(info->pset, memb) != NULL)
+                       continue;
+
+               plug = aset_get(root->pset, memb);
+               result = set_plugin(&info->pset, memb, plug);
+               if (result != 0)
+                       break;
+       }
+       if (result != 0) {
+               warning("nikita-3447",
+                       "Cannot set up plugins for %lli",
+                       (unsigned long long)
+                       get_inode_oid(inode));
+       }
+       return result;
+}
+
+int force_plugin_pset(struct inode *self, pset_member memb, reiser4_plugin * plug)
+{
+       reiser4_inode *info;
+       int result = 0;
+
+       if (!self->i_sb->s_root || self->i_sb->s_root->d_inode == self) {
+               /* Changing pset in the root object. */
+               return RETERR(-EINVAL);
+       }
+
+       info = reiser4_inode_data(self);
+       if (plug->h.pops != NULL && plug->h.pops->change != NULL)
+               result = plug->h.pops->change(self, plug, memb);
+       else
+               result = aset_set_unsafe(&info->pset, memb, plug);
+       if (result == 0) {
+               __u16 oldmask = info->plugin_mask;
+
+               update_pset_mask(info, memb);
+               if (oldmask != info->plugin_mask)
+                       reiser4_inode_clr_flag(self, REISER4_SDLEN_KNOWN);
+       }
+       return result;
+}
+
+reiser4_plugin_type_data plugins[REISER4_PLUGIN_TYPES] = {
+       /* C90 initializers */
+       [REISER4_FILE_PLUGIN_TYPE] = {
+               .type_id = REISER4_FILE_PLUGIN_TYPE,
+               .label = "file",
+               .desc = "Object plugins",
+               .builtin_num = sizeof_array(file_plugins),
+               .builtin = file_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(file_plugin)
+       },
+       [REISER4_DIR_PLUGIN_TYPE] = {
+               .type_id = REISER4_DIR_PLUGIN_TYPE,
+               .label = "dir",
+               .desc = "Directory plugins",
+               .builtin_num = sizeof_array(dir_plugins),
+               .builtin = dir_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(dir_plugin)
+       },
+       [REISER4_HASH_PLUGIN_TYPE] = {
+               .type_id = REISER4_HASH_PLUGIN_TYPE,
+               .label = "hash",
+               .desc = "Directory hashes",
+               .builtin_num = sizeof_array(hash_plugins),
+               .builtin = hash_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(hash_plugin)
+       },
+       [REISER4_FIBRATION_PLUGIN_TYPE] = {
+               .type_id =
+               REISER4_FIBRATION_PLUGIN_TYPE,
+               .label = "fibration",
+               .desc = "Directory fibrations",
+               .builtin_num = sizeof_array(fibration_plugins),
+               .builtin = fibration_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(fibration_plugin)
+       },
+       [REISER4_CIPHER_PLUGIN_TYPE] = {
+               .type_id = REISER4_CIPHER_PLUGIN_TYPE,
+               .label = "cipher",
+               .desc = "Cipher plugins",
+               .builtin_num = sizeof_array(cipher_plugins),
+               .builtin = cipher_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(cipher_plugin)
+       },
+       [REISER4_DIGEST_PLUGIN_TYPE] = {
+               .type_id = REISER4_DIGEST_PLUGIN_TYPE,
+               .label = "digest",
+               .desc = "Digest plugins",
+               .builtin_num = sizeof_array(digest_plugins),
+               .builtin = digest_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(digest_plugin)
+       },
+       [REISER4_COMPRESSION_PLUGIN_TYPE] = {
+               .type_id = REISER4_COMPRESSION_PLUGIN_TYPE,
+               .label = "compression",
+               .desc = "Compression plugins",
+               .builtin_num = sizeof_array(compression_plugins),
+               .builtin = compression_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(compression_plugin)
+       },
+       [REISER4_FORMATTING_PLUGIN_TYPE] = {
+               .type_id = REISER4_FORMATTING_PLUGIN_TYPE,
+               .label = "formatting",
+               .desc = "Tail inlining policies",
+               .builtin_num = sizeof_array(formatting_plugins),
+               .builtin = formatting_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(formatting_plugin)
+       },
+       [REISER4_PERM_PLUGIN_TYPE] = {
+               .type_id = REISER4_PERM_PLUGIN_TYPE,
+               .label = "perm",
+               .desc = "Permission checks",
+               .builtin_num = sizeof_array(perm_plugins),
+               .builtin = perm_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(perm_plugin)
+       },
+       [REISER4_ITEM_PLUGIN_TYPE] = {
+               .type_id = REISER4_ITEM_PLUGIN_TYPE,
+               .label = "item",
+               .desc = "Item handlers",
+               .builtin_num = sizeof_array(item_plugins),
+               .builtin = item_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(item_plugin)
+       },
+       [REISER4_NODE_PLUGIN_TYPE] = {
+               .type_id = REISER4_NODE_PLUGIN_TYPE,
+               .label = "node",
+               .desc = "node layout handlers",
+               .builtin_num = sizeof_array(node_plugins),
+               .builtin = node_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(node_plugin)
+       },
+       [REISER4_SD_EXT_PLUGIN_TYPE] = {
+               .type_id = REISER4_SD_EXT_PLUGIN_TYPE,
+               .label = "sd_ext",
+               .desc = "Parts of stat-data",
+               .builtin_num = sizeof_array(sd_ext_plugins),
+               .builtin = sd_ext_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(sd_ext_plugin)
+       },
+       [REISER4_FORMAT_PLUGIN_TYPE] = {
+               .type_id = REISER4_FORMAT_PLUGIN_TYPE,
+               .label = "disk_layout",
+               .desc = "defines filesystem on disk layout",
+               .builtin_num = sizeof_array(format_plugins),
+               .builtin = format_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(disk_format_plugin)
+       },
+       [REISER4_JNODE_PLUGIN_TYPE] = {
+               .type_id = REISER4_JNODE_PLUGIN_TYPE,
+               .label = "jnode",
+               .desc = "defines kind of jnode",
+               .builtin_num = sizeof_array(jnode_plugins),
+               .builtin = jnode_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(jnode_plugin)
+       },
+       [REISER4_COMPRESSION_MODE_PLUGIN_TYPE] = {
+               .type_id = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+               .label = "compression_mode",
+               .desc = "Defines compression mode",
+               .builtin_num = sizeof_array(compression_mode_plugins),
+               .builtin = compression_mode_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(compression_mode_plugin)
+       },
+       [REISER4_CLUSTER_PLUGIN_TYPE] = {
+               .type_id = REISER4_CLUSTER_PLUGIN_TYPE,
+               .label = "cluster",
+               .desc = "Defines cluster size",
+               .builtin_num = sizeof_array(cluster_plugins),
+               .builtin = cluster_plugins,
+               .plugins_list = {NULL, NULL},
+               .size = sizeof(cluster_plugin)
+       }
+};
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/plugin.h linux-2.6.20/fs/reiser4/plugin/plugin.h
--- linux-2.6.20.orig/fs/reiser4/plugin/plugin.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/plugin.h     2007-05-06 14:50:43.855024468 +0400
@@ -0,0 +1,920 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Basic plugin data-types.
+   see fs/reiser4/plugin/plugin.c for details */
+
+#if !defined( __FS_REISER4_PLUGIN_TYPES_H__ )
+#define __FS_REISER4_PLUGIN_TYPES_H__
+
+#include "../forward.h"
+#include "../debug.h"
+#include "../dformat.h"
+#include "../key.h"
+#include "compress/compress.h"
+#include "crypto/cipher.h"
+#include "plugin_header.h"
+#include "item/static_stat.h"
+#include "item/internal.h"
+#include "item/sde.h"
+#include "item/cde.h"
+#include "item/item.h"
+#include "node/node.h"
+#include "node/node40.h"
+#include "security/perm.h"
+#include "fibration.h"
+
+#include "space/bitmap.h"
+#include "space/space_allocator.h"
+
+#include "disk_format/disk_format40.h"
+#include "disk_format/disk_format.h"
+
+#include <linux/fs.h>          /* for struct super_block, address_space  */
+#include <linux/mm.h>          /* for struct page */
+#include <linux/buffer_head.h> /* for struct buffer_head */
+#include <linux/dcache.h>      /* for struct dentry */
+#include <linux/types.h>
+#include <linux/crypto.h>
+
+typedef struct reiser4_object_on_wire reiser4_object_on_wire;
+
+/*
+ * File plugin.  Defines the set of methods that file plugins implement, some
+ * of which are optional.
+ *
+ * A file plugin offers to the caller an interface for IO ( writing to and/or
+ * reading from) to what the caller sees as one sequence of bytes.  An IO to it
+ * may affect more than one physical sequence of bytes, or no physical sequence
+ * of bytes, it may affect sequences of bytes offered by other file plugins to
+ * the semantic layer, and the file plugin may invoke other plugins and
+ * delegate work to them, but its interface is structured for offering the
+ * caller the ability to read and/or write what the caller sees as being a
+ * single sequence of bytes.
+ *
+ * The file plugin must present a sequence of bytes to the caller, but it does
+ * not necessarily have to store a sequence of bytes, it does not necessarily
+ * have to support efficient tree traversal to any offset in the sequence of
+ * bytes (tail and extent items, whose keys contain offsets, do however provide
+ * efficient non-sequential lookup of any offset in the sequence of bytes).
+ *
+ * Directory plugins provide methods for selecting file plugins by resolving a
+ * name for them.
+ *
+ * The functionality other filesystems call an attribute, and rigidly tie
+ * together, we decompose into orthogonal selectable features of files.  Using
+ * the terminology we will define next, an attribute is a perhaps constrained,
+ * perhaps static length, file whose parent has a uni-count-intra-link to it,
+ * which might be grandparent-major-packed, and whose parent has a deletion
+ * method that deletes it.
+ *
+ * File plugins can implement constraints.
+ *
+ * Files can be of variable length (e.g. regular unix files), or of static
+ * length (e.g. static sized attributes).
+ *
+ * An object may have many sequences of bytes, and many file plugins, but, it
+ * has exactly one objectid.  It is usually desirable that an object has a
+ * deletion method which deletes every item with that objectid.  Items cannot
+ * in general be found by just their objectids.  This means that an object must
+ * have either a method built into its deletion plugin method for knowing what
+ * items need to be deleted, or links stored with the object that provide the
+ * plugin with a method for finding those items.  Deleting a file within an
+ * object may or may not have the effect of deleting the entire object,
+ * depending on the file plugin's deletion method.
+ *
+ * LINK TAXONOMY:
+ *
+ * Many objects have a reference count, and when the reference count reaches 0
+ * the object's deletion method is invoked.  Some links embody a reference
+ * count increase ("countlinks"), and others do not ("nocountlinks").
+ *
+ * Some links are bi-directional links ("bilinks"), and some are
+ * uni-directional("unilinks").
+ *
+ * Some links are between parts of the same object ("intralinks"), and some are
+ * between different objects ("interlinks").
+ *
+ * PACKING TAXONOMY:
+ *
+ * Some items of an object are stored with a major packing locality based on
+ * their object's objectid (e.g. unix directory items in plan A), and these are
+ * called "self-major-packed".
+ *
+ * Some items of an object are stored with a major packing locality based on
+ * their semantic parent object's objectid (e.g. unix file bodies in plan A),
+ * and these are called "parent-major-packed".
+ *
+ * Some items of an object are stored with a major packing locality based on
+ * their semantic grandparent, and these are called "grandparent-major-packed".
+ * Now carefully notice that we run into trouble with key length if we have to
+ * store a 8 byte major+minor grandparent based packing locality, an 8 byte
+ * parent objectid, an 8 byte attribute objectid, and an 8 byte offset, all in
+ * a 24 byte key.  One of these fields must be sacrificed if an item is to be
+ * grandparent-major-packed, and which to sacrifice is left to the item author
+ * choosing to make the item grandparent-major-packed.  You cannot make tail
+ * items and extent items grandparent-major-packed, though you could make them
+ * self-major-packed (usually they are parent-major-packed).
+ *
+ * In the case of ACLs (which are composed of fixed length ACEs which consist
+ * of {subject-type, subject, and permission bitmask} triples), it makes sense
+ * to not have an offset field in the ACE item key, and to allow duplicate keys
+ * for ACEs.  Thus, the set of ACES for a given file is found by looking for a
+ * key consisting of the objectid of the grandparent (thus grouping all ACLs in
+ * a directory together), the minor packing locality of ACE, the objectid of
+ * the file, and 0.
+ *
+ * IO involves moving data from one location to another, which means that two
+ * locations must be specified, source and destination.
+ *
+ * This source and destination can be in the filesystem, or they can be a
+ * pointer in the user process address space plus a byte count.
+ *
+ * If both source and destination are in the filesystem, then at least one of
+ * them must be representable as a pure stream of bytes (which we call a flow,
+ * and define as a struct containing a key, a data pointer, and a length).
+ * This may mean converting one of them into a flow.  We provide a generic
+ * cast_into_flow() method, which will work for any plugin supporting
+ * read_flow(), though it is inefficiently implemented in that it temporarily
+ * stores the flow in a buffer (Question: what to do with huge flows that
+ * cannot fit into memory?  Answer: we must not convert them all at once. )
+ *
+ * Performing a write requires resolving the write request into a flow defining
+ * the source, and a method that performs the write, and a key that defines
+ * where in the tree the write is to go.
+ *
+ * Performing a read requires resolving the read request into a flow defining
+ * the target, and a method that performs the read, and a key that defines
+ * where in the tree the read is to come from.
+ *
+ * There will exist file plugins which have no pluginid stored on the disk for
+ * them, and which are only invoked by other plugins.
+ */
+
+/* This should be incremented with each new contributed
+   pair (plugin type, plugin id).
+   NOTE: Make sure there is a release of reiser4progs
+   with the corresponding version number */
+#define PLUGIN_LIBRARY_VERSION 0
+
+ /* enumeration of fields within plugin_set */
+typedef enum {
+       PSET_FILE,
+       PSET_DIR,               /* PSET_FILE and PSET_DIR should be first elements:
+                                * inode.c:read_inode() depends on this. */
+       PSET_PERM,
+       PSET_FORMATTING,
+       PSET_HASH,
+       PSET_FIBRATION,
+       PSET_SD,
+       PSET_DIR_ITEM,
+       PSET_CIPHER,
+       PSET_DIGEST,
+       PSET_COMPRESSION,
+       PSET_COMPRESSION_MODE,
+       PSET_CLUSTER,
+       PSET_CREATE,
+       PSET_LAST
+} pset_member;
+
+/* builtin file-plugins */
+typedef enum {
+       /* regular file */
+       UNIX_FILE_PLUGIN_ID,
+       /* directory */
+       DIRECTORY_FILE_PLUGIN_ID,
+       /* symlink */
+       SYMLINK_FILE_PLUGIN_ID,
+       /* for objects completely handled by the VFS: fifos, devices,
+          sockets  */
+       SPECIAL_FILE_PLUGIN_ID,
+       /* regular cryptcompress file */
+       CRYPTCOMPRESS_FILE_PLUGIN_ID,
+       /* number of file plugins. Used as size of arrays to hold
+          file plugins. */
+       LAST_FILE_PLUGIN_ID
+} reiser4_file_id;
+
+typedef struct file_plugin {
+
+       /* generic fields */
+       plugin_header h;
+
+       struct inode_operations inode_ops;
+       struct file_operations file_ops;
+       struct address_space_operations as_ops;
+
+       /* save inode cached stat-data onto disk. It was called
+          reiserfs_update_sd() in 3.x */
+       int (*write_sd_by_inode) (struct inode *);
+
+       /*
+        * private methods: These are optional.  If used they will allow you to
+        * minimize the amount of code needed to implement a deviation from
+        * some other method that also uses them.
+        */
+
+       /*
+        * Construct flow into @flow according to user-supplied data.
+        *
+        * This is used by read/write methods to construct a flow to
+        * write/read. ->flow_by_inode() is plugin method, rather than single
+        * global implementation, because key in a flow used by plugin may
+        * depend on data in a @buf.
+        *
+        * NIKITA-FIXME-HANS: please create statistics on what functions are
+        * dereferenced how often for the mongo benchmark.  You can supervise
+        * Elena doing this for you if that helps.  Email me the list of the
+        * top 10, with their counts, and an estimate of the total number of
+        * CPU cycles spent dereferencing as a percentage of CPU cycles spent
+        * processing (non-idle processing).  If the total percent is, say,
+        * less than 1%, it will make our coding discussions much easier, and
+        * keep me from questioning whether functions like the below are too
+        * frequently called to be dereferenced.  If the total percent is more
+        * than 1%, perhaps private methods should be listed in a "required"
+        * comment at the top of each plugin (with stern language about how if
+        * the comment is missing it will not be accepted by the maintainer),
+        * and implemented using macros not dereferenced functions.  How about
+        * replacing this whole private methods part of the struct with a
+        * thorough documentation of what the standard helper functions are for
+        * use in constructing plugins?  I think users have been asking for
+        * that, though not in so many words.
+        */
+       int (*flow_by_inode) (struct inode *, const char __user *buf,
+                             int user, loff_t size,
+                             loff_t off, rw_op op, flow_t *);
+
+       /*
+        * Return the key used to retrieve an offset of a file. It is used by
+        * default implementation of ->flow_by_inode() method
+        * (common_build_flow()) and, among other things, to get to the extent
+        * from jnode of unformatted node.
+        */
+       int (*key_by_inode) (struct inode *, loff_t off, reiser4_key *);
+
+       /* NIKITA-FIXME-HANS: this comment is not as clear to others as you think.... */
+       /*
+        * set the plugin for a file.  Called during file creation in creat()
+        * but not reiser4() unless an inode already exists for the file.
+        */
+       int (*set_plug_in_inode) (struct inode *inode, struct inode *parent,
+                                 reiser4_object_create_data *);
+
+       /* NIKITA-FIXME-HANS: comment and name seem to say different things,
+        * are you setting up the object itself also or just adjusting the
+        * parent?.... */
+       /* set up plugins for new @object created in @parent. @root is root
+          directory. */
+       int (*adjust_to_parent) (struct inode *object, struct inode *parent,
+                                struct inode *root);
+       /*
+        * this does whatever is necessary to do when object is created. For
+        * instance, for unix files stat data is inserted. It is supposed to be
+        * called by create of struct inode_operations.
+        */
+       int (*create_object) (struct inode *object, struct inode *parent,
+                             reiser4_object_create_data *);
+
+       /* this does whatever is necessary to do when object is opened */
+       int (*open_object) (struct inode * inode, struct file * file);
+       /*
+        * this method should check REISER4_NO_SD and set REISER4_NO_SD on
+        * success. Deletion of an object usually includes removal of items
+        * building file body (for directories this is removal of "." and "..")
+        * and removal of stat-data item.
+        */
+       int (*delete_object) (struct inode *);
+
+       /* add link from @parent to @object */
+       int (*add_link) (struct inode *object, struct inode *parent);
+
+       /* remove link from @parent to @object */
+       int (*rem_link) (struct inode *object, struct inode *parent);
+
+       /*
+        * return true if item addressed by @coord belongs to @inode.  This is
+        * used by read/write to properly slice flow into items in presence of
+        * multiple key assignment policies, because items of a file are not
+        * necessarily contiguous in a key space, for example, in a plan-b.
+        */
+       int (*owns_item) (const struct inode *, const coord_t *);
+
+       /* checks whether yet another hard links to this object can be
+          added  */
+       int (*can_add_link) (const struct inode *);
+
+       /* checks whether hard links to this object can be removed */
+       int (*can_rem_link) (const struct inode *);
+
+       /* not empty for DIRECTORY_FILE_PLUGIN_ID only currently. It calls
+          detach of directory plugin to remove ".." */
+       int (*detach) (struct inode * child, struct inode * parent);
+
+       /* called when @child was just looked up in the @parent. It is not
+          empty for DIRECTORY_FILE_PLUGIN_ID only where it calls attach of
+          directory plugin */
+       int (*bind) (struct inode * child, struct inode * parent);
+
+       /* process safe-link during mount */
+       int (*safelink) (struct inode * object, reiser4_safe_link_t link,
+                        __u64 value);
+
+       /* The couple of estimate methods for all file operations */
+       struct {
+               reiser4_block_nr(*create) (const struct inode *);
+               reiser4_block_nr(*update) (const struct inode *);
+               reiser4_block_nr(*unlink) (const struct inode *,
+                                          const struct inode *);
+       } estimate;
+
+       /*
+        * reiser4 specific part of inode has a union of structures which are
+        * specific to a plugin. This method is called when inode is read
+        * (read_inode) and when file is created (common_create_child) so that
+        * file plugin could initialize its inode data
+        */
+       void (*init_inode_data) (struct inode *, reiser4_object_create_data *,
+                                int);
+
+       /*
+        * This method performs progressive deletion of items and whole nodes
+        * from right to left.
+        *
+        * @tap: the point deletion process begins from,
+        * @from_key: the beginning of the deleted key range,
+        * @to_key: the end of the deleted key range,
+        * @smallest_removed: the smallest removed key,
+        *
+        * @return: 0 if success, error code otherwise, -E_REPEAT means that long cut_tree
+        * operation was interrupted for allowing atom commit .
+        */
+       int (*cut_tree_worker) (tap_t *, const reiser4_key * from_key,
+                               const reiser4_key * to_key,
+                               reiser4_key * smallest_removed, struct inode *,
+                               int, int *);
+
+       /* called from ->destroy_inode() */
+       void (*destroy_inode) (struct inode *);
+
+       /*
+        * methods to serialize object identify. This is used, for example, by
+        * reiser4_{en,de}code_fh().
+        */
+       struct {
+               /* store object's identity at @area */
+               char *(*write) (struct inode * inode, char *area);
+               /* parse object from wire to the @obj */
+               char *(*read) (char *area, reiser4_object_on_wire * obj);
+               /* given object identity in @obj, find or create its dentry */
+               struct dentry *(*get) (struct super_block * s,
+                                      reiser4_object_on_wire * obj);
+               /* how many bytes ->wire.write() consumes */
+               int (*size) (struct inode * inode);
+               /* finish with object identify */
+               void (*done) (reiser4_object_on_wire * obj);
+       } wire;
+} file_plugin;
+
+extern file_plugin file_plugins[LAST_FILE_PLUGIN_ID];
+
+struct reiser4_object_on_wire {
+       file_plugin *plugin;
+       union {
+               struct {
+                       obj_key_id key_id;
+               } std;
+               void *generic;
+       } u;
+};
+
+/* builtin dir-plugins */
+typedef enum {
+       HASHED_DIR_PLUGIN_ID,
+       SEEKABLE_HASHED_DIR_PLUGIN_ID,
+       LAST_DIR_ID
+} reiser4_dir_id;
+
+typedef struct dir_plugin {
+       /* generic fields */
+       plugin_header h;
+
+       struct inode_operations inode_ops;
+       struct file_operations file_ops;
+       struct address_space_operations as_ops;
+
+       /*
+        * private methods: These are optional.  If used they will allow you to
+        * minimize the amount of code needed to implement a deviation from
+        * some other method that uses them.  You could logically argue that
+        * they should be a separate type of plugin.
+        */
+
+       struct dentry *(*get_parent) (struct inode * childdir);
+
+       /*
+        * check whether "name" is acceptable name to be inserted into this
+        * object. Optionally implemented by directory-like objects.  Can check
+        * for maximal length, reserved symbols etc
+        */
+       int (*is_name_acceptable) (const struct inode * inode, const char *name,
+                                  int len);
+
+       void (*build_entry_key) (const struct inode * dir       /* directory where
+                                                                * entry is (or will
+                                                                * be) in.*/ ,
+                                const struct qstr * name       /* name of file
+                                                                * referenced by this
+                                                                * entry */ ,
+                                reiser4_key * result   /* resulting key of
+                                                        * directory entry */ );
+       int (*build_readdir_key) (struct file * dir, reiser4_key * result);
+       int (*add_entry) (struct inode * object, struct dentry * where,
+                         reiser4_object_create_data * data,
+                         reiser4_dir_entry_desc * entry);
+       int (*rem_entry) (struct inode * object, struct dentry * where,
+                         reiser4_dir_entry_desc * entry);
+
+       /*
+        * initialize directory structure for newly created object. For normal
+        * unix directories, insert dot and dotdot.
+        */
+       int (*init) (struct inode * object, struct inode * parent,
+                    reiser4_object_create_data * data);
+
+       /* destroy directory */
+       int (*done) (struct inode * child);
+
+       /* called when @subdir was just looked up in the @dir */
+       int (*attach) (struct inode * subdir, struct inode * dir);
+       int (*detach) (struct inode * subdir, struct inode * dir);
+
+       struct {
+               reiser4_block_nr(*add_entry) (const struct inode *);
+               reiser4_block_nr(*rem_entry) (const struct inode *);
+               reiser4_block_nr(*unlink) (const struct inode *,
+                                          const struct inode *);
+       } estimate;
+} dir_plugin;
+
+extern dir_plugin dir_plugins[LAST_DIR_ID];
+
+typedef struct formatting_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* returns non-zero iff file's tail has to be stored
+          in a direct item. */
+       int (*have_tail) (const struct inode * inode, loff_t size);
+} formatting_plugin;
+
+typedef struct hash_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* computes hash of the given name */
+        __u64(*hash) (const unsigned char *name, int len);
+} hash_plugin;
+
+typedef struct cipher_plugin {
+       /* generic fields */
+       plugin_header h;
+       struct crypto_blkcipher * (*alloc) (void);
+       void (*free) (struct crypto_blkcipher * tfm);
+       /* Offset translator. For each offset this returns (k * offset), where
+          k (k >= 1) is an expansion factor of the cipher algorithm.
+          For all symmetric algorithms k == 1. For asymmetric algorithms (which
+          inflate data) offset translation guarantees that all disk cluster's
+          units will have keys smaller then next cluster's one.
+        */
+        loff_t(*scale) (struct inode * inode, size_t blocksize, loff_t src);
+       /* Cipher algorithms can accept data only by chunks of cipher block
+          size. This method is to align any flow up to cipher block size when
+          we pass it to cipher algorithm. To align means to append padding of
+          special format specific to the cipher algorithm */
+       int (*align_stream) (__u8 * tail, int clust_size, int blocksize);
+       /* low-level key manager (check, install, etc..) */
+       int (*setkey) (struct crypto_tfm * tfm, const __u8 * key,
+                      unsigned int keylen);
+       /* main text processing procedures */
+       void (*encrypt) (__u32 * expkey, __u8 * dst, const __u8 * src);
+       void (*decrypt) (__u32 * expkey, __u8 * dst, const __u8 * src);
+} cipher_plugin;
+
+typedef struct digest_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* fingerprint size in bytes */
+       int fipsize;
+       struct crypto_hash * (*alloc) (void);
+       void (*free) (struct crypto_hash * tfm);
+} digest_plugin;
+
+typedef struct compression_plugin {
+       /* generic fields */
+       plugin_header h;
+       int (*init) (void);
+       /* the maximum number of bytes the size of the "compressed" data can
+        * exceed the uncompressed data. */
+       int (*overrun) (unsigned src_len);
+        coa_t(*alloc) (tfm_action act);
+       void (*free) (coa_t coa, tfm_action act);
+       /* minimal size of the flow we still try to compress */
+       int (*min_size_deflate) (void);
+        __u32(*checksum) (char *data, __u32 length);
+       /* main transform procedures */
+       void (*compress) (coa_t coa, __u8 * src_first, unsigned src_len,
+                         __u8 * dst_first, unsigned *dst_len);
+       void (*decompress) (coa_t coa, __u8 * src_first, unsigned src_len,
+                           __u8 * dst_first, unsigned *dst_len);
+} compression_plugin;
+
+typedef struct compression_mode_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* this is called when estimating compressibility
+          of a logical cluster by its content */
+       int (*should_deflate) (struct inode * inode, cloff_t index);
+       /* this is called when results of compression should be saved */
+       int (*accept_hook) (struct inode * inode, cloff_t index);
+       /* this is called when results of compression should be discarded */
+       int (*discard_hook) (struct inode * inode, cloff_t index);
+} compression_mode_plugin;
+
+typedef struct cluster_plugin {
+       /* generic fields */
+       plugin_header h;
+       int shift;
+} cluster_plugin;
+
+typedef struct sd_ext_plugin {
+       /* generic fields */
+       plugin_header h;
+       int (*present) (struct inode * inode, char **area, int *len);
+       int (*absent) (struct inode * inode);
+       int (*save_len) (struct inode * inode);
+       int (*save) (struct inode * inode, char **area);
+       /* alignment requirement for this stat-data part */
+       int alignment;
+} sd_ext_plugin;
+
+/* this plugin contains methods to allocate objectid for newly created files,
+   to deallocate objectid when file gets removed, to report number of used and
+   free objectids */
+typedef struct oid_allocator_plugin {
+       /* generic fields */
+       plugin_header h;
+       int (*init_oid_allocator) (reiser4_oid_allocator * map, __u64 nr_files,
+                                  __u64 oids);
+       /* used to report statfs->f_files */
+        __u64(*oids_used) (reiser4_oid_allocator * map);
+       /* get next oid to use */
+        __u64(*next_oid) (reiser4_oid_allocator * map);
+       /* used to report statfs->f_ffree */
+        __u64(*oids_free) (reiser4_oid_allocator * map);
+       /* allocate new objectid */
+       int (*allocate_oid) (reiser4_oid_allocator * map, oid_t *);
+       /* release objectid */
+       int (*release_oid) (reiser4_oid_allocator * map, oid_t);
+       /* how many pages to reserve in transaction for allocation of new
+          objectid */
+       int (*oid_reserve_allocate) (reiser4_oid_allocator * map);
+       /* how many pages to reserve in transaction for freeing of an
+          objectid */
+       int (*oid_reserve_release) (reiser4_oid_allocator * map);
+       void (*print_info) (const char *, reiser4_oid_allocator *);
+} oid_allocator_plugin;
+
+/* disk layout plugin: this specifies super block, journal, bitmap (if there
+   are any) locations, etc */
+typedef struct disk_format_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* replay journal, initialize super_info_data, etc */
+       int (*init_format) (struct super_block *, void *data);
+
+       /* key of root directory stat data */
+       const reiser4_key *(*root_dir_key) (const struct super_block *);
+
+       int (*release) (struct super_block *);
+       jnode *(*log_super) (struct super_block *);
+       int (*check_open) (const struct inode * object);
+       int (*version_update) (struct super_block *);
+} disk_format_plugin;
+
+struct jnode_plugin {
+       /* generic fields */
+       plugin_header h;
+       int (*init) (jnode * node);
+       int (*parse) (jnode * node);
+       struct address_space *(*mapping) (const jnode * node);
+       unsigned long (*index) (const jnode * node);
+       jnode *(*clone) (jnode * node);
+};
+
+/* plugin instance.                                                         */
+/*                                                                          */
+/* This is "wrapper" union for all types of plugins. Most of the code uses  */
+/* plugins of particular type (file_plugin, dir_plugin, etc.)  rather than  */
+/* operates with pointers to reiser4_plugin. This union is only used in     */
+/* some generic code in plugin/plugin.c that operates on all                */
+/* plugins. Technically speaking purpose of this union is to add type       */
+/* safety to said generic code: each plugin type (file_plugin, for          */
+/* example), contains plugin_header as its first memeber. This first member */
+/* is located at the same place in memory as .h member of                   */
+/* reiser4_plugin. Generic code, obtains pointer to reiser4_plugin and      */
+/* looks in the .h which is header of plugin type located in union. This    */
+/* allows to avoid type-casts.                                              */
+union reiser4_plugin {
+       /* generic fields */
+       plugin_header h;
+       /* file plugin */
+       file_plugin file;
+       /* directory plugin */
+       dir_plugin dir;
+       /* hash plugin, used by directory plugin */
+       hash_plugin hash;
+       /* fibration plugin used by directory plugin */
+       fibration_plugin fibration;
+       /* cipher transform plugin, used by file plugin */
+       cipher_plugin cipher;
+       /* digest transform plugin, used by file plugin */
+       digest_plugin digest;
+       /* compression transform plugin, used by file plugin */
+       compression_plugin compression;
+       /* tail plugin, used by file plugin */
+       formatting_plugin formatting;
+       /* permission plugin */
+       perm_plugin perm;
+       /* node plugin */
+       node_plugin node;
+       /* item plugin */
+       item_plugin item;
+       /* stat-data extension plugin */
+       sd_ext_plugin sd_ext;
+       /* disk layout plugin */
+       disk_format_plugin format;
+       /* object id allocator plugin */
+       oid_allocator_plugin oid_allocator;
+       /* plugin for different jnode types */
+       jnode_plugin jnode;
+       /* compression mode plugin, used by object plugin */
+       compression_mode_plugin compression_mode;
+       /* cluster plugin, used by object plugin */
+       cluster_plugin clust;
+       /* place-holder for new plugin types that can be registered
+          dynamically, and used by other dynamically loaded plugins.  */
+       void *generic;
+};
+
+struct reiser4_plugin_ops {
+       /* called when plugin is initialized */
+       int (*init) (reiser4_plugin * plugin);
+       /* called when plugin is unloaded */
+       int (*done) (reiser4_plugin * plugin);
+       /* load given plugin from disk */
+       int (*load) (struct inode * inode,
+                    reiser4_plugin * plugin, char **area, int *len);
+       /* how many space is required to store this plugin's state
+          in stat-data */
+       int (*save_len) (struct inode * inode, reiser4_plugin * plugin);
+       /* save persistent plugin-data to disk */
+       int (*save) (struct inode * inode, reiser4_plugin * plugin,
+                    char **area);
+       /* alignment requirement for on-disk state of this plugin
+          in number of bytes */
+       int alignment;
+       /* install itself into given inode. This can return error
+          (e.g., you cannot change hash of non-empty directory). */
+       int (*change) (struct inode * inode, reiser4_plugin * plugin,
+                      pset_member memb);
+       /* install itself into given inode. This can return error
+          (e.g., you cannot change hash of non-empty directory). */
+       int (*inherit) (struct inode * inode, struct inode * parent,
+                       reiser4_plugin * plugin);
+};
+
+/* functions implemented in fs/reiser4/plugin/plugin.c */
+
+/* stores plugin reference in reiser4-specific part of inode */
+extern int set_object_plugin(struct inode *inode, reiser4_plugin_id id);
+extern int setup_plugins(struct super_block *super, reiser4_plugin ** area);
+extern int init_plugins(void);
+
+/* builtin plugins */
+
+/* builtin hash-plugins */
+
+typedef enum {
+       RUPASOV_HASH_ID,
+       R5_HASH_ID,
+       TEA_HASH_ID,
+       FNV1_HASH_ID,
+       DEGENERATE_HASH_ID,
+       LAST_HASH_ID
+} reiser4_hash_id;
+
+/* builtin cipher plugins */
+
+typedef enum {
+       NONE_CIPHER_ID,
+       LAST_CIPHER_ID
+} reiser4_cipher_id;
+
+/* builtin digest plugins */
+
+typedef enum {
+       SHA256_32_DIGEST_ID,
+       LAST_DIGEST_ID
+} reiser4_digest_id;
+
+/* builtin compression mode plugins */
+typedef enum {
+       NONE_COMPRESSION_MODE_ID,
+       LATTD_COMPRESSION_MODE_ID,
+       ULTIM_COMPRESSION_MODE_ID,
+       FORCE_COMPRESSION_MODE_ID,
+       CONVX_COMPRESSION_MODE_ID,
+       LAST_COMPRESSION_MODE_ID
+} reiser4_compression_mode_id;
+
+/* builtin cluster plugins */
+typedef enum {
+       CLUSTER_64K_ID,
+       CLUSTER_32K_ID,
+       CLUSTER_16K_ID,
+       CLUSTER_8K_ID,
+       CLUSTER_4K_ID,
+       LAST_CLUSTER_ID
+} reiser4_cluster_id;
+
+/* builtin tail-plugins */
+
+typedef enum {
+       NEVER_TAILS_FORMATTING_ID,
+       ALWAYS_TAILS_FORMATTING_ID,
+       SMALL_FILE_FORMATTING_ID,
+       LAST_TAIL_FORMATTING_ID
+} reiser4_formatting_id;
+
+/* compression/clustering specific data */
+typedef struct compression_data {
+       reiser4_compression_id coa;     /* id of the compression algorithm */
+} compression_data_t;
+
+typedef __u8 cluster_data_t;   /* cluster info */
+
+/* data type used to pack parameters that we pass to vfs object creation
+   function create_object() */
+struct reiser4_object_create_data {
+       /* plugin to control created object */
+       reiser4_file_id id;
+       /* mode of regular file, directory or special file */
+/* what happens if some other sort of perm plugin is in use? */
+       int mode;
+       /* rdev of special file */
+       dev_t rdev;
+       /* symlink target */
+       const char *name;
+       /* add here something for non-standard objects you invent, like
+          query for interpolation file etc. */
+
+       crypto_stat_t * crypto;
+       compression_data_t *compression;
+       cluster_data_t *cluster;
+
+       struct inode *parent;
+       struct dentry *dentry;
+};
+
+/* description of directory entry being created/destroyed/sought for
+
+   It is passed down to the directory plugin and farther to the
+   directory item plugin methods. Creation of new directory is done in
+   several stages: first we search for an entry with the same name, then
+   create new one. reiser4_dir_entry_desc is used to store some information
+   collected at some stage of this process and required later: key of
+   item that we want to insert/delete and pointer to an object that will
+   be bound by the new directory entry. Probably some more fields will
+   be added there.
+
+*/
+struct reiser4_dir_entry_desc {
+       /* key of directory entry */
+       reiser4_key key;
+       /* object bound by this entry. */
+       struct inode *obj;
+};
+
+#define MAX_PLUGIN_TYPE_LABEL_LEN  32
+#define MAX_PLUGIN_PLUG_LABEL_LEN  32
+
+/* used for interface with user-land: table-driven parsing in
+    reiser4(). */
+typedef struct plugin_locator {
+       reiser4_plugin_type type_id;
+       reiser4_plugin_id id;
+       char type_label[MAX_PLUGIN_TYPE_LABEL_LEN];
+       char plug_label[MAX_PLUGIN_PLUG_LABEL_LEN];
+} plugin_locator;
+
+extern int locate_plugin(struct inode *inode, plugin_locator * loc);
+
+#define PLUGIN_BY_ID(TYPE,ID,FIELD)                                    \
+static inline TYPE *TYPE ## _by_id( reiser4_plugin_id id )             \
+{                                                                      \
+       reiser4_plugin *plugin = plugin_by_id ( ID, id );               \
+       return plugin ? & plugin -> FIELD : NULL;                       \
+}                                                                      \
+static inline TYPE *TYPE ## _by_disk_id( reiser4_tree *tree, d16 *id ) \
+{                                                                      \
+       reiser4_plugin *plugin = plugin_by_disk_id ( tree, ID, id );    \
+       return plugin ? & plugin -> FIELD : NULL;                       \
+}                                                                      \
+static inline TYPE *TYPE ## _by_unsafe_id( reiser4_plugin_id id )      \
+{                                                                      \
+       reiser4_plugin *plugin = plugin_by_unsafe_id ( ID, id );        \
+       return plugin ? & plugin -> FIELD : NULL;                       \
+}                                                                      \
+static inline reiser4_plugin* TYPE ## _to_plugin( TYPE* plugin )       \
+{                                                                      \
+       return ( reiser4_plugin * ) plugin;                             \
+}                                                                      \
+static inline reiser4_plugin_id TYPE ## _id( TYPE* plugin )            \
+{                                                                      \
+       return TYPE ## _to_plugin (plugin) -> h.id;                     \
+}                                                                      \
+typedef struct { int foo; } TYPE ## _plugin_dummy
+
+PLUGIN_BY_ID(item_plugin, REISER4_ITEM_PLUGIN_TYPE, item);
+PLUGIN_BY_ID(file_plugin, REISER4_FILE_PLUGIN_TYPE, file);
+PLUGIN_BY_ID(dir_plugin, REISER4_DIR_PLUGIN_TYPE, dir);
+PLUGIN_BY_ID(node_plugin, REISER4_NODE_PLUGIN_TYPE, node);
+PLUGIN_BY_ID(sd_ext_plugin, REISER4_SD_EXT_PLUGIN_TYPE, sd_ext);
+PLUGIN_BY_ID(perm_plugin, REISER4_PERM_PLUGIN_TYPE, perm);
+PLUGIN_BY_ID(hash_plugin, REISER4_HASH_PLUGIN_TYPE, hash);
+PLUGIN_BY_ID(fibration_plugin, REISER4_FIBRATION_PLUGIN_TYPE, fibration);
+PLUGIN_BY_ID(cipher_plugin, REISER4_CIPHER_PLUGIN_TYPE, cipher);
+PLUGIN_BY_ID(digest_plugin, REISER4_DIGEST_PLUGIN_TYPE, digest);
+PLUGIN_BY_ID(compression_plugin, REISER4_COMPRESSION_PLUGIN_TYPE, compression);
+PLUGIN_BY_ID(formatting_plugin, REISER4_FORMATTING_PLUGIN_TYPE, formatting);
+PLUGIN_BY_ID(disk_format_plugin, REISER4_FORMAT_PLUGIN_TYPE, format);
+PLUGIN_BY_ID(jnode_plugin, REISER4_JNODE_PLUGIN_TYPE, jnode);
+PLUGIN_BY_ID(compression_mode_plugin, REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+            compression_mode);
+PLUGIN_BY_ID(cluster_plugin, REISER4_CLUSTER_PLUGIN_TYPE, clust);
+
+extern int save_plugin_id(reiser4_plugin * plugin, d16 * area);
+
+extern struct list_head *get_plugin_list(reiser4_plugin_type type_id);
+
+#define for_all_plugins(ptype, plugin)                                                 \
+for (plugin = list_entry(get_plugin_list(ptype)->next, reiser4_plugin, h.linkage);     \
+     get_plugin_list(ptype) != &plugin->h.linkage;                                     \
+     plugin = list_entry(plugin->h.linkage.next, reiser4_plugin, h.linkage))
+
+
+extern int grab_plugin_pset(struct inode *self, struct inode *ancestor, pset_member memb);
+extern int force_plugin_pset(struct inode *self, pset_member memb, reiser4_plugin *plug);
+extern int finish_pset(struct inode *inode);
+
+/* defined in fs/reiser4/plugin/object.c */
+extern file_plugin file_plugins[LAST_FILE_PLUGIN_ID];
+/* defined in fs/reiser4/plugin/object.c */
+extern dir_plugin dir_plugins[LAST_DIR_ID];
+/* defined in fs/reiser4/plugin/item/static_stat.c */
+extern sd_ext_plugin sd_ext_plugins[LAST_SD_EXTENSION];
+/* defined in fs/reiser4/plugin/hash.c */
+extern hash_plugin hash_plugins[LAST_HASH_ID];
+/* defined in fs/reiser4/plugin/fibration.c */
+extern fibration_plugin fibration_plugins[LAST_FIBRATION_ID];
+/* defined in fs/reiser4/plugin/crypt.c */
+extern cipher_plugin cipher_plugins[LAST_CIPHER_ID];
+/* defined in fs/reiser4/plugin/digest.c */
+extern digest_plugin digest_plugins[LAST_DIGEST_ID];
+/* defined in fs/reiser4/plugin/compress/compress.c */
+extern compression_plugin compression_plugins[LAST_COMPRESSION_ID];
+/* defined in fs/reiser4/plugin/compress/compression_mode.c */
+extern compression_mode_plugin
+compression_mode_plugins[LAST_COMPRESSION_MODE_ID];
+/* defined in fs/reiser4/plugin/cluster.c */
+extern cluster_plugin cluster_plugins[LAST_CLUSTER_ID];
+/* defined in fs/reiser4/plugin/tail.c */
+extern formatting_plugin formatting_plugins[LAST_TAIL_FORMATTING_ID];
+/* defined in fs/reiser4/plugin/security/security.c */
+extern perm_plugin perm_plugins[LAST_PERM_ID];
+/* defined in fs/reiser4/plugin/item/item.c */
+extern item_plugin item_plugins[LAST_ITEM_ID];
+/* defined in fs/reiser4/plugin/node/node.c */
+extern node_plugin node_plugins[LAST_NODE_ID];
+/* defined in fs/reiser4/plugin/disk_format/disk_format.c */
+extern disk_format_plugin format_plugins[LAST_FORMAT_ID];
+
+/* __FS_REISER4_PLUGIN_TYPES_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/plugin_header.h linux-2.6.20/fs/reiser4/plugin/plugin_header.h
--- linux-2.6.20.orig/fs/reiser4/plugin/plugin_header.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/plugin_header.h      2007-05-06 14:50:43.855024468 +0400
@@ -0,0 +1,144 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* plugin header. Data structures required by all plugin types. */
+
+#if !defined( __PLUGIN_HEADER_H__ )
+#define __PLUGIN_HEADER_H__
+
+/* plugin data-types and constants */
+
+#include "../debug.h"
+#include "../dformat.h"
+
+typedef enum {
+       REISER4_FILE_PLUGIN_TYPE,
+       REISER4_DIR_PLUGIN_TYPE,
+       REISER4_ITEM_PLUGIN_TYPE,
+       REISER4_NODE_PLUGIN_TYPE,
+       REISER4_HASH_PLUGIN_TYPE,
+       REISER4_FIBRATION_PLUGIN_TYPE,
+       REISER4_FORMATTING_PLUGIN_TYPE,
+       REISER4_PERM_PLUGIN_TYPE,
+       REISER4_SD_EXT_PLUGIN_TYPE,
+       REISER4_FORMAT_PLUGIN_TYPE,
+       REISER4_JNODE_PLUGIN_TYPE,
+       REISER4_CIPHER_PLUGIN_TYPE,
+       REISER4_DIGEST_PLUGIN_TYPE,
+       REISER4_COMPRESSION_PLUGIN_TYPE,
+       REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+       REISER4_CLUSTER_PLUGIN_TYPE,
+       REISER4_PLUGIN_TYPES
+} reiser4_plugin_type;
+
+typedef enum {
+       REISER4_DIRECTORY_FILE,
+       REISER4_REGULAR_FILE,
+       REISER4_SYMLINK_FILE,
+       REISER4_SPECIAL_FILE,
+} reiser4_plugin_group;
+
+struct reiser4_plugin_ops;
+/* generic plugin operations, supported by each
+    plugin type. */
+typedef struct reiser4_plugin_ops reiser4_plugin_ops;
+
+/* the common part of all plugin instances. */
+typedef struct plugin_header {
+       /* plugin type */
+       reiser4_plugin_type type_id;
+       /* id of this plugin */
+       reiser4_plugin_id id;
+       /* bitmask of groups the plugin belongs to. */
+       reiser4_plugin_groups groups;
+       /* plugin operations */
+       reiser4_plugin_ops *pops;
+/* NIKITA-FIXME-HANS: usage of and access to label and desc is not commented and defined. */
+       /* short label of this plugin */
+       const char *label;
+       /* descriptive string.. */
+       const char *desc;
+       /* list linkage */
+       struct list_head linkage;
+} plugin_header;
+
+#define plugin_of_group(plug, group) (plug->h.groups & (1 << group))
+
+/* PRIVATE INTERFACES */
+/* NIKITA-FIXME-HANS: what is this for and why does it duplicate what is in plugin_header? */
+/* plugin type representation. */
+typedef struct reiser4_plugin_type_data {
+       /* internal plugin type identifier. Should coincide with
+          index of this item in plugins[] array. */
+       reiser4_plugin_type type_id;
+       /* short symbolic label of this plugin type. Should be no longer
+          than MAX_PLUGIN_TYPE_LABEL_LEN characters including '\0'. */
+       const char *label;
+       /* plugin type description longer than .label */
+       const char *desc;
+
+/* NIKITA-FIXME-HANS: define built-in */
+       /* number of built-in plugin instances of this type */
+       int builtin_num;
+       /* array of built-in plugins */
+       void *builtin;
+       struct list_head plugins_list;
+       size_t size;
+} reiser4_plugin_type_data;
+
+extern reiser4_plugin_type_data plugins[REISER4_PLUGIN_TYPES];
+
+int is_plugin_type_valid(reiser4_plugin_type type);
+int is_plugin_id_valid(reiser4_plugin_type type, reiser4_plugin_id id);
+
+static inline reiser4_plugin *plugin_at(reiser4_plugin_type_data * ptype, int i)
+{
+       char *builtin;
+
+       builtin = ptype->builtin;
+       return (reiser4_plugin *) (builtin + i * ptype->size);
+}
+
+/* return plugin by its @type_id and @id */
+static inline reiser4_plugin *plugin_by_id(reiser4_plugin_type type,
+                                          reiser4_plugin_id id)
+{
+       assert("nikita-1651", is_plugin_type_valid(type));
+       assert("nikita-1652", is_plugin_id_valid(type, id));
+       return plugin_at(&plugins[type], id);
+}
+
+extern reiser4_plugin *plugin_by_unsafe_id(reiser4_plugin_type type_id,
+                                          reiser4_plugin_id id);
+
+/**
+ * plugin_by_disk_id - get reiser4_plugin
+ * @type_id: plugin type id
+ * @did: plugin id in disk format
+ *
+ * Returns reiser4_plugin by plugin type id an dplugin_id.
+ */
+static inline reiser4_plugin *plugin_by_disk_id(reiser4_tree * tree UNUSED_ARG,
+                                               reiser4_plugin_type type_id,
+                                               __le16 *plugin_id)
+{
+       /*
+        * what we should do properly is to maintain within each file-system a
+        * dictionary that maps on-disk plugin ids to "universal" ids. This
+        * dictionary will be resolved on mount time, so that this function
+        * will perform just one additional array lookup.
+        */
+       return plugin_by_unsafe_id(type_id, le16_to_cpu(*plugin_id));
+}
+
+/* __PLUGIN_HEADER_H__ */
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/plugin_set.c linux-2.6.20/fs/reiser4/plugin/plugin_set.c
--- linux-2.6.20.orig/fs/reiser4/plugin/plugin_set.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/plugin_set.c 2007-05-06 14:50:43.855024468 +0400
@@ -0,0 +1,379 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+/* This file contains Reiser4 plugin set operations */
+
+/* plugin sets
+ *
+ * Each file in reiser4 is controlled by a whole set of plugins (file plugin,
+ * directory plugin, hash plugin, tail policy plugin, security plugin, etc.)
+ * assigned (inherited, deduced from mode bits, etc.) at creation time. This
+ * set of plugins (so called pset) is described by structure plugin_set (see
+ * plugin/plugin_set.h), which contains pointers to all required plugins.
+ *
+ * Children can inherit some pset members from their parent, however sometimes
+ * it is useful to specify members different from parent ones. Since object's
+ * pset can not be easily changed without fatal consequences, we use for this
+ * purpose another special plugin table (so called hset, or heir set) described
+ * by the same structure.
+ *
+ * Inode only stores a pointers to pset and hset. Different inodes with the
+ * same set of pset (hset) members point to the same pset (hset). This is
+ * archived by storing psets and hsets in global hash table. Races are avoided
+ * by simple (and efficient so far) solution of never recycling psets, even
+ * when last inode pointing to it is destroyed.
+ */
+
+#include "../debug.h"
+#include "../super.h"
+#include "plugin_set.h"
+
+#include <linux/slab.h>
+#include <linux/stddef.h>
+
+/* slab for plugin sets */
+static struct kmem_cache *plugin_set_slab;
+
+static spinlock_t plugin_set_lock[8] __cacheline_aligned_in_smp = {
+       [0 ... 7] = SPIN_LOCK_UNLOCKED
+};
+
+/* hash table support */
+
+#define PS_TABLE_SIZE (32)
+
+static inline plugin_set *cast_to(const unsigned long *a)
+{
+       return container_of(a, plugin_set, hashval);
+}
+
+static inline int pseq(const unsigned long *a1, const unsigned long *a2)
+{
+       plugin_set *set1;
+       plugin_set *set2;
+
+       /* make sure fields are not missed in the code below */
+       cassert(sizeof *set1 ==
+               sizeof set1->hashval +
+               sizeof set1->link +
+               sizeof set1->file +
+               sizeof set1->dir +
+               sizeof set1->perm +
+               sizeof set1->formatting +
+               sizeof set1->hash +
+               sizeof set1->fibration +
+               sizeof set1->sd +
+               sizeof set1->dir_item +
+               sizeof set1->cipher +
+               sizeof set1->digest +
+               sizeof set1->compression +
+               sizeof set1->compression_mode +
+               sizeof set1->cluster +
+               sizeof set1->create);
+
+       set1 = cast_to(a1);
+       set2 = cast_to(a2);
+       return
+           set1->hashval == set2->hashval &&
+           set1->file == set2->file &&
+           set1->dir == set2->dir &&
+           set1->perm == set2->perm &&
+           set1->formatting == set2->formatting &&
+           set1->hash == set2->hash &&
+           set1->fibration == set2->fibration &&
+           set1->sd == set2->sd &&
+           set1->dir_item == set2->dir_item &&
+           set1->cipher == set2->cipher &&
+           set1->digest == set2->digest &&
+           set1->compression == set2->compression &&
+           set1->compression_mode == set2->compression_mode &&
+           set1->cluster == set2->cluster &&
+           set1->create == set2->create;
+}
+
+#define HASH_FIELD(hash, set, field)           \
+({                                             \
+        (hash) += (unsigned long)(set)->field >> 2;    \
+})
+
+static inline unsigned long calculate_hash(const plugin_set * set)
+{
+       unsigned long result;
+
+       result = 0;
+       HASH_FIELD(result, set, file);
+       HASH_FIELD(result, set, dir);
+       HASH_FIELD(result, set, perm);
+       HASH_FIELD(result, set, formatting);
+       HASH_FIELD(result, set, hash);
+       HASH_FIELD(result, set, fibration);
+       HASH_FIELD(result, set, sd);
+       HASH_FIELD(result, set, dir_item);
+       HASH_FIELD(result, set, cipher);
+       HASH_FIELD(result, set, digest);
+       HASH_FIELD(result, set, compression);
+       HASH_FIELD(result, set, compression_mode);
+       HASH_FIELD(result, set, cluster);
+       HASH_FIELD(result, set, create);
+       return result & (PS_TABLE_SIZE - 1);
+}
+
+static inline unsigned long
+pshash(ps_hash_table * table, const unsigned long *a)
+{
+       return *a;
+}
+
+/* The hash table definition */
+#define KMALLOC(size) kmalloc((size), reiser4_ctx_gfp_mask_get())
+#define KFREE(ptr, size) kfree(ptr)
+TYPE_SAFE_HASH_DEFINE(ps, plugin_set, unsigned long, hashval, link, pshash,
+                     pseq);
+#undef KFREE
+#undef KMALLOC
+
+static ps_hash_table ps_table;
+static plugin_set empty_set = {
+       .hashval = 0,
+       .file = NULL,
+       .dir = NULL,
+       .perm = NULL,
+       .formatting = NULL,
+       .hash = NULL,
+       .fibration = NULL,
+       .sd = NULL,
+       .dir_item = NULL,
+       .cipher = NULL,
+       .digest = NULL,
+       .compression = NULL,
+       .compression_mode = NULL,
+       .cluster = NULL,
+       .create = NULL,
+       .link = {NULL}
+};
+
+plugin_set *plugin_set_get_empty(void)
+{
+       return &empty_set;
+}
+
+void plugin_set_put(plugin_set * set)
+{
+}
+
+static inline unsigned long *pset_field(plugin_set * set, int offset)
+{
+       return (unsigned long *)(((char *)set) + offset);
+}
+
+static int plugin_set_field(plugin_set ** set, const unsigned long val,
+                           const int offset)
+{
+       unsigned long *spot;
+       spinlock_t *lock;
+       plugin_set replica;
+       plugin_set *twin;
+       plugin_set *psal;
+       plugin_set *orig;
+
+       assert("nikita-2902", set != NULL);
+       assert("nikita-2904", *set != NULL);
+
+       spot = pset_field(*set, offset);
+       if (unlikely(*spot == val))
+               return 0;
+
+       replica = *(orig = *set);
+       *pset_field(&replica, offset) = val;
+       replica.hashval = calculate_hash(&replica);
+       rcu_read_lock();
+       twin = ps_hash_find(&ps_table, &replica.hashval);
+       if (unlikely(twin == NULL)) {
+               rcu_read_unlock();
+               psal = kmem_cache_alloc(plugin_set_slab,
+                                       reiser4_ctx_gfp_mask_get());
+               if (psal == NULL)
+                       return RETERR(-ENOMEM);
+               *psal = replica;
+               lock = &plugin_set_lock[replica.hashval & 7];
+               spin_lock(lock);
+               twin = ps_hash_find(&ps_table, &replica.hashval);
+               if (likely(twin == NULL)) {
+                       *set = psal;
+                       ps_hash_insert_rcu(&ps_table, psal);
+               } else {
+                       *set = twin;
+                       kmem_cache_free(plugin_set_slab, psal);
+               }
+               spin_unlock(lock);
+       } else {
+               rcu_read_unlock();
+               *set = twin;
+       }
+       return 0;
+}
+
+static struct {
+       int offset;
+       reiser4_plugin_groups groups;
+       reiser4_plugin_type type;
+} pset_descr[PSET_LAST] = {
+       [PSET_FILE] = {
+               .offset = offsetof(plugin_set, file),
+               .type = REISER4_FILE_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_DIR] = {
+               .offset = offsetof(plugin_set, dir),
+               .type = REISER4_DIR_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_PERM] = {
+               .offset = offsetof(plugin_set, perm),
+               .type = REISER4_PERM_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_FORMATTING] = {
+               .offset = offsetof(plugin_set, formatting),
+               .type = REISER4_FORMATTING_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_HASH] = {
+               .offset = offsetof(plugin_set, hash),
+               .type = REISER4_HASH_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_FIBRATION] = {
+               .offset = offsetof(plugin_set, fibration),
+               .type = REISER4_FIBRATION_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_SD] = {
+               .offset = offsetof(plugin_set, sd),
+               .type = REISER4_ITEM_PLUGIN_TYPE,
+               .groups = (1 << STAT_DATA_ITEM_TYPE)
+       },
+       [PSET_DIR_ITEM] = {
+               .offset = offsetof(plugin_set, dir_item),
+               .type = REISER4_ITEM_PLUGIN_TYPE,
+               .groups = (1 << DIR_ENTRY_ITEM_TYPE)
+       },
+       [PSET_CIPHER] = {
+               .offset = offsetof(plugin_set, cipher),
+               .type = REISER4_CIPHER_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_DIGEST] = {
+               .offset = offsetof(plugin_set, digest),
+               .type = REISER4_DIGEST_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_COMPRESSION] = {
+               .offset = offsetof(plugin_set, compression),
+               .type = REISER4_COMPRESSION_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_COMPRESSION_MODE] = {
+               .offset = offsetof(plugin_set, compression_mode),
+               .type = REISER4_COMPRESSION_MODE_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_CLUSTER] = {
+               .offset = offsetof(plugin_set, cluster),
+               .type = REISER4_CLUSTER_PLUGIN_TYPE,
+               .groups = 0
+       },
+       [PSET_CREATE] = {
+               .offset = offsetof(plugin_set, create),
+               .type = REISER4_FILE_PLUGIN_TYPE,
+               .groups = (1 << REISER4_REGULAR_FILE)
+       }
+};
+
+#define DEFINE_PSET_OPS(PREFIX)                                                       \
+       reiser4_plugin_type PREFIX##_member_to_type_unsafe(pset_member memb)   \
+{                                                                             \
+       if (memb > PSET_LAST)                                                  \
+               return REISER4_PLUGIN_TYPES;                                   \
+       return pset_descr[memb].type;                                          \
+}                                                                             \
+                                                                              \
+int PREFIX##_set_unsafe(plugin_set ** set, pset_member memb,                  \
+                    reiser4_plugin * plugin)                                  \
+{                                                                             \
+       assert("nikita-3492", set != NULL);                                    \
+       assert("nikita-3493", *set != NULL);                                   \
+       assert("nikita-3494", plugin != NULL);                                 \
+       assert("nikita-3495", 0 <= memb && memb < PSET_LAST);                  \
+       assert("nikita-3496", plugin->h.type_id == pset_descr[memb].type);     \
+                                                                              \
+       if (pset_descr[memb].groups)                                           \
+               if (!(pset_descr[memb].groups & plugin->h.groups))             \
+                       return -EINVAL;                                        \
+                                                                              \
+       return plugin_set_field(set,                                           \
+                       (unsigned long)plugin, pset_descr[memb].offset);       \
+}                                                                             \
+                                                                              \
+reiser4_plugin *PREFIX##_get(plugin_set * set, pset_member memb)              \
+{                                                                             \
+       assert("nikita-3497", set != NULL);                                    \
+       assert("nikita-3498", 0 <= memb && memb < PSET_LAST);                  \
+                                                                              \
+       return *(reiser4_plugin **) (((char *)set) + pset_descr[memb].offset); \
+}
+
+DEFINE_PSET_OPS(aset);
+
+int set_plugin(plugin_set ** set, pset_member memb, reiser4_plugin * plugin) {
+       return plugin_set_field(set,
+               (unsigned long)plugin, pset_descr[memb].offset);
+}
+
+/**
+ * init_plugin_set - create plugin set cache and hash table
+ *
+ * Initializes slab cache of plugin_set-s and their hash table. It is part of
+ * reiser4 module initialization.
+ */
+int init_plugin_set(void)
+{
+       int result;
+
+       result = ps_hash_init(&ps_table, PS_TABLE_SIZE);
+       if (result == 0) {
+               plugin_set_slab = kmem_cache_create("plugin_set",
+                                                   sizeof(plugin_set), 0,
+                                                   SLAB_HWCACHE_ALIGN,
+                                                   NULL, NULL);
+               if (plugin_set_slab == NULL)
+                       result = RETERR(-ENOMEM);
+       }
+       return result;
+}
+
+/**
+ * done_plugin_set - delete plugin_set cache and plugin_set hash table
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void done_plugin_set(void)
+{
+       plugin_set *cur, *next;
+
+       for_all_in_htable(&ps_table, ps, cur, next) {
+               ps_hash_remove(&ps_table, cur);
+               kmem_cache_free(plugin_set_slab, cur);
+       }
+       destroy_reiser4_cache(&plugin_set_slab);
+       ps_hash_done(&ps_table);
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/plugin_set.h linux-2.6.20/fs/reiser4/plugin/plugin_set.h
--- linux-2.6.20.orig/fs/reiser4/plugin/plugin_set.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/plugin_set.h 2007-05-06 14:50:43.855024468 +0400
@@ -0,0 +1,77 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Reiser4 plugin set definition.
+   See fs/reiser4/plugin/plugin_set.c for details */
+
+#if !defined( __PLUGIN_SET_H__ )
+#define __PLUGIN_SET_H__
+
+#include "../type_safe_hash.h"
+#include "plugin.h"
+
+#include <linux/rcupdate.h>
+
+struct plugin_set;
+typedef struct plugin_set plugin_set;
+
+TYPE_SAFE_HASH_DECLARE(ps, plugin_set);
+
+struct plugin_set {
+       unsigned long hashval;
+       /* plugin of file */
+       file_plugin *file;
+       /* plugin of dir */
+       dir_plugin *dir;
+       /* perm plugin for this file */
+       perm_plugin *perm;
+       /* tail policy plugin. Only meaningful for regular files */
+       formatting_plugin *formatting;
+       /* hash plugin. Only meaningful for directories. */
+       hash_plugin *hash;
+       /* fibration plugin. Only meaningful for directories. */
+       fibration_plugin *fibration;
+       /* plugin of stat-data */
+       item_plugin *sd;
+       /* plugin of items a directory is built of */
+       item_plugin *dir_item;
+       /* cipher plugin */
+       cipher_plugin *cipher;
+       /* digest plugin */
+       digest_plugin *digest;
+       /* compression plugin */
+       compression_plugin *compression;
+       /* compression mode plugin */
+       compression_mode_plugin *compression_mode;
+       /* cluster plugin */
+       cluster_plugin *cluster;
+       /* this specifies file plugin of regular children.
+          only meaningful for directories */
+       file_plugin *create;
+       ps_hash_link link;
+};
+
+extern plugin_set *plugin_set_get_empty(void);
+extern void plugin_set_put(plugin_set * set);
+
+extern int init_plugin_set(void);
+extern void done_plugin_set(void);
+
+extern reiser4_plugin *aset_get(plugin_set * set, pset_member memb);
+extern int set_plugin(plugin_set ** set, pset_member memb,
+                     reiser4_plugin * plugin);
+extern int aset_set_unsafe(plugin_set ** set, pset_member memb,
+                          reiser4_plugin * plugin);
+extern reiser4_plugin_type aset_member_to_type_unsafe(pset_member memb);
+
+/* __PLUGIN_SET_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/security/Makefile linux-2.6.20/fs/reiser4/plugin/security/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/security/Makefile       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/security/Makefile    2007-05-06 14:50:43.855024468 +0400
@@ -0,0 +1,4 @@
+obj-$(CONFIG_REISER4_FS) += security_plugins.o
+
+security_plugins-objs :=       \
+       perm.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/security/perm.c linux-2.6.20/fs/reiser4/plugin/security/perm.c
--- linux-2.6.20.orig/fs/reiser4/plugin/security/perm.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/security/perm.c      2007-05-06 14:50:43.859025718 +0400
@@ -0,0 +1,44 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/*
+ * this file contains implementation of permission plugins. Currently, only
+ * RWX_PERM_ID is implemented
+ */
+
+#include "../plugin.h"
+#include "../plugin_header.h"
+#include "../../debug.h"
+
+perm_plugin perm_plugins[LAST_PERM_ID] = {
+       [NULL_PERM_ID] = {
+               .h = {
+                       .type_id = REISER4_PERM_PLUGIN_TYPE,
+                       .id = NULL_PERM_ID,
+                       .pops = NULL,
+                       .label = "null",
+                       .desc = "stub permission plugin",
+                       .linkage = {NULL, NULL}
+               },
+               .read_ok = NULL,
+               .write_ok = NULL,
+               .lookup_ok = NULL,
+               .create_ok = NULL,
+               .link_ok = NULL,
+               .unlink_ok = NULL,
+               .delete_ok = NULL,
+               .mask_ok = NULL,
+               .setattr_ok = NULL,
+               .getattr_ok = NULL,
+               .rename_ok = NULL,
+       }
+};
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/security/perm.h linux-2.6.20/fs/reiser4/plugin/security/perm.h
--- linux-2.6.20.orig/fs/reiser4/plugin/security/perm.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/security/perm.h      2007-05-06 14:50:43.859025718 +0400
@@ -0,0 +1,82 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Perm (short for "permissions") plugins common stuff. */
+
+#if !defined( __REISER4_PERM_H__ )
+#define __REISER4_PERM_H__
+
+#include "../../forward.h"
+#include "../plugin_header.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>          /* for struct file  */
+#include <linux/dcache.h>      /* for struct dentry */
+
+/* interface for perm plugin.
+
+   Perm plugin method can be implemented through:
+
+    1. consulting ->i_mode bits in stat data
+
+    2. obtaining acl from the tree and inspecting it
+
+    3. asking some kernel module or user-level program to authorize access.
+
+   This allows for integration with things like capabilities, SELinux-style
+   secutiry contexts, etc.
+
+*/
+/* NIKITA-FIXME-HANS: define what this is targeted for.  It does not seem to be intended for use with sys_reiser4.  Explain. */
+typedef struct perm_plugin {
+       /* generic plugin fields */
+       plugin_header h;
+
+       /* check permissions for read/write */
+       int (*read_ok) (struct file *file, const char __user *buf,
+                       size_t size, loff_t *off);
+       int (*write_ok) (struct file *file, const char __user *buf,
+                        size_t size, loff_t *off);
+
+       /* check permissions for lookup */
+       int (*lookup_ok) (struct inode * parent, struct dentry * dentry);
+
+       /* check permissions for create */
+       int (*create_ok) (struct inode * parent, struct dentry * dentry,
+                         reiser4_object_create_data * data);
+
+       /* check permissions for linking @where to @existing */
+       int (*link_ok) (struct dentry * existing, struct inode * parent,
+                       struct dentry * where);
+
+       /* check permissions for unlinking @victim from @parent */
+       int (*unlink_ok) (struct inode * parent, struct dentry * victim);
+
+       /* check permissions for deletion of @object whose last reference is
+          by @parent */
+       int (*delete_ok) (struct inode * parent, struct dentry * victim);
+       int (*mask_ok) (struct inode * inode, int mask);
+       /* check whether attribute change is acceptable */
+       int (*setattr_ok) (struct dentry * dentry, struct iattr * attr);
+
+       /* check whether stat(2) is allowed */
+       int (*getattr_ok) (struct vfsmount * mnt UNUSED_ARG,
+                          struct dentry * dentry, struct kstat * stat);
+       /* check whether rename(2) is allowed */
+       int (*rename_ok) (struct inode * old_dir, struct dentry * old,
+                         struct inode * new_dir, struct dentry * new);
+} perm_plugin;
+
+typedef enum { NULL_PERM_ID, LAST_PERM_ID } reiser4_perm_id;
+
+/* __REISER4_PERM_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/space/bitmap.c linux-2.6.20/fs/reiser4/plugin/space/bitmap.c
--- linux-2.6.20.orig/fs/reiser4/plugin/space/bitmap.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/space/bitmap.c       2007-05-06 14:50:43.859025718 +0400
@@ -0,0 +1,1585 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#include "../../debug.h"
+#include "../../dformat.h"
+#include "../../txnmgr.h"
+#include "../../jnode.h"
+#include "../../block_alloc.h"
+#include "../../tree.h"
+#include "../../super.h"
+#include "../plugin.h"
+#include "space_allocator.h"
+#include "bitmap.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/mutex.h>
+#include <asm/div64.h>
+
+/* Proposed (but discarded) optimization: dynamic loading/unloading of bitmap
+ * blocks
+
+   A useful optimization of reiser4 bitmap handling would be dynamic bitmap
+   blocks loading/unloading which is different from v3.x where all bitmap
+   blocks are loaded at mount time.
+
+   To implement bitmap blocks unloading we need to count bitmap block usage
+   and detect currently unused blocks allowing them to be unloaded. It is not
+   a simple task since we allow several threads to modify one bitmap block
+   simultaneously.
+
+   Briefly speaking, the following schema is proposed: we count in special
+   variable associated with each bitmap block. That is for counting of block
+   alloc/dealloc operations on that bitmap block. With a deferred block
+   deallocation feature of reiser4 all those operation will be represented in
+   atom dirty/deleted lists as jnodes for freshly allocated or deleted
+   nodes.
+
+   So, we increment usage counter for each new node allocated or deleted, and
+   decrement it at atom commit one time for each node from the dirty/deleted
+   atom's list.  Of course, freshly allocated node deletion and node reusing
+   from atom deleted (if we do so) list should decrement bitmap usage counter
+   also.
+
+   This schema seems to be working but that reference counting is
+   not easy to debug. I think we should agree with Hans and do not implement
+   it in v4.0. Current code implements "on-demand" bitmap blocks loading only.
+
+   For simplicity all bitmap nodes (both commit and working bitmap blocks) are
+   loaded into memory on fs mount time or each bitmap nodes are loaded at the
+   first access to it, the "dont_load_bitmap" mount option controls whether
+   bimtap nodes should be loaded at mount time. Dynamic unloading of bitmap
+   nodes currently is not supported. */
+
+#define CHECKSUM_SIZE    4
+
+#define BYTES_PER_LONG   (sizeof(long))
+
+#if BITS_PER_LONG == 64
+#  define LONG_INT_SHIFT (6)
+#else
+#  define LONG_INT_SHIFT (5)
+#endif
+
+#define LONG_INT_MASK (BITS_PER_LONG - 1UL)
+
+typedef unsigned long ulong_t;
+
+#define bmap_size(blocksize)       ((blocksize) - CHECKSUM_SIZE)
+#define bmap_bit_count(blocksize)   (bmap_size(blocksize) << 3)
+
+/* Block allocation/deallocation are done through special bitmap objects which
+   are allocated in an array at fs mount. */
+struct bitmap_node {
+       struct mutex mutex;     /* long term lock object */
+
+       jnode *wjnode;          /* j-nodes for WORKING ... */
+       jnode *cjnode;          /* ... and COMMIT bitmap blocks */
+
+       bmap_off_t first_zero_bit;      /* for skip_busy option implementation */
+
+       atomic_t loaded;        /* a flag which shows that bnode is loaded
+                                * already */
+};
+
+static inline char *bnode_working_data(struct bitmap_node *bnode)
+{
+       char *data;
+
+       data = jdata(bnode->wjnode);
+       assert("zam-429", data != NULL);
+
+       return data + CHECKSUM_SIZE;
+}
+
+static inline char *bnode_commit_data(const struct bitmap_node *bnode)
+{
+       char *data;
+
+       data = jdata(bnode->cjnode);
+       assert("zam-430", data != NULL);
+
+       return data + CHECKSUM_SIZE;
+}
+
+static inline __u32 bnode_commit_crc(const struct bitmap_node *bnode)
+{
+       char *data;
+
+       data = jdata(bnode->cjnode);
+       assert("vpf-261", data != NULL);
+
+       return le32_to_cpu(get_unaligned((d32 *)data));
+}
+
+static inline void bnode_set_commit_crc(struct bitmap_node *bnode, __u32 crc)
+{
+       char *data;
+
+       data = jdata(bnode->cjnode);
+       assert("vpf-261", data != NULL);
+
+       put_unaligned(cpu_to_le32(crc), (d32 *)data);
+}
+
+/* ZAM-FIXME-HANS: is the idea that this might be a union someday? having
+ * written the code, does this added abstraction still have */
+/* ANSWER(Zam): No, the abstractions is in the level above (exact place is the
+ * reiser4_space_allocator structure) */
+/* ZAM-FIXME-HANS: I don't understand your english in comment above. */
+/* FIXME-HANS(Zam): I don't understand the questions like "might be a union
+ * someday?". What they about?  If there is a reason to have a union, it should
+ * be a union, if not, it should not be a union.  "..might be someday" means no
+ * reason. */
+struct bitmap_allocator_data {
+       /* an array for bitmap blocks direct access */
+       struct bitmap_node *bitmap;
+};
+
+#define get_barray(super) \
+(((struct bitmap_allocator_data *)(get_super_private(super)->space_allocator.u.generic)) -> bitmap)
+
+#define get_bnode(super, i) (get_barray(super) + i)
+
+/* allocate and initialize jnode with JNODE_BITMAP type */
+static jnode *bnew(void)
+{
+       jnode *jal = jalloc();
+
+       if (jal)
+               jnode_init(jal, current_tree, JNODE_BITMAP);
+
+       return jal;
+}
+
+/* this file contains:
+   - bitmap based implementation of space allocation plugin
+   - all the helper functions like set bit, find_first_zero_bit, etc */
+
+/* Audited by: green(2002.06.12) */
+static int find_next_zero_bit_in_word(ulong_t word, int start_bit)
+{
+       ulong_t mask = 1UL << start_bit;
+       int i = start_bit;
+
+       while ((word & mask) != 0) {
+               mask <<= 1;
+               if (++i >= BITS_PER_LONG)
+                       break;
+       }
+
+       return i;
+}
+
+#include <asm/bitops.h>
+
+#if BITS_PER_LONG == 64
+
+#define OFF(addr)  (((ulong_t)(addr) & (BYTES_PER_LONG - 1)) << 3)
+#define BASE(addr) ((ulong_t*) ((ulong_t)(addr) & ~(BYTES_PER_LONG - 1)))
+
+static inline void reiser4_set_bit(int nr, void *addr)
+{
+       ext2_set_bit(nr + OFF(addr), BASE(addr));
+}
+
+static inline void reiser4_clear_bit(int nr, void *addr)
+{
+       ext2_clear_bit(nr + OFF(addr), BASE(addr));
+}
+
+static inline int reiser4_test_bit(int nr, void *addr)
+{
+       return ext2_test_bit(nr + OFF(addr), BASE(addr));
+}
+static inline int reiser4_find_next_zero_bit(void *addr, int maxoffset,
+                                            int offset)
+{
+       int off = OFF(addr);
+
+       return ext2_find_next_zero_bit(BASE(addr), maxoffset + off,
+                                      offset + off) - off;
+}
+
+#else
+
+#define reiser4_set_bit(nr, addr)    ext2_set_bit(nr, addr)
+#define reiser4_clear_bit(nr, addr)  ext2_clear_bit(nr, addr)
+#define reiser4_test_bit(nr, addr)  ext2_test_bit(nr, addr)
+
+#define reiser4_find_next_zero_bit(addr, maxoffset, offset) \
+ext2_find_next_zero_bit(addr, maxoffset, offset)
+#endif
+
+/* Search for a set bit in the bit array [@start_offset, @max_offset[, offsets
+ * are counted from @addr, return the offset of the first bit if it is found,
+ * @maxoffset otherwise. */
+static bmap_off_t __reiser4_find_next_set_bit(void *addr, bmap_off_t max_offset,
+                                             bmap_off_t start_offset)
+{
+       ulong_t *base = addr;
+       /* start_offset is in bits, convert it to byte offset within bitmap. */
+       int word_nr = start_offset >> LONG_INT_SHIFT;
+       /* bit number within the byte. */
+       int bit_nr = start_offset & LONG_INT_MASK;
+       int max_word_nr = (max_offset - 1) >> LONG_INT_SHIFT;
+
+       assert("zam-387", max_offset != 0);
+
+       /* Unaligned @start_offset case.  */
+       if (bit_nr != 0) {
+               bmap_nr_t nr;
+
+               nr = find_next_zero_bit_in_word(~(base[word_nr]), bit_nr);
+
+               if (nr < BITS_PER_LONG)
+                       return (word_nr << LONG_INT_SHIFT) + nr;
+
+               ++word_nr;
+       }
+
+       /* Fast scan trough aligned words. */
+       while (word_nr <= max_word_nr) {
+               if (base[word_nr] != 0) {
+                       return (word_nr << LONG_INT_SHIFT)
+                           + find_next_zero_bit_in_word(~(base[word_nr]), 0);
+               }
+
+               ++word_nr;
+       }
+
+       return max_offset;
+}
+
+#if BITS_PER_LONG == 64
+
+static bmap_off_t reiser4_find_next_set_bit(void *addr, bmap_off_t max_offset,
+                                           bmap_off_t start_offset)
+{
+       bmap_off_t off = OFF(addr);
+
+       return __reiser4_find_next_set_bit(BASE(addr), max_offset + off,
+                                          start_offset + off) - off;
+}
+
+#else
+#define reiser4_find_next_set_bit(addr, max_offset, start_offset) \
+  __reiser4_find_next_set_bit(addr, max_offset, start_offset)
+#endif
+
+/* search for the first set bit in single word. */
+static int find_last_set_bit_in_word(ulong_t word, int start_bit)
+{
+       ulong_t bit_mask;
+       int nr = start_bit;
+
+       assert("zam-965", start_bit < BITS_PER_LONG);
+       assert("zam-966", start_bit >= 0);
+
+       bit_mask = (1UL << nr);
+
+       while (bit_mask != 0) {
+               if (bit_mask & word)
+                       return nr;
+               bit_mask >>= 1;
+               nr--;
+       }
+       return BITS_PER_LONG;
+}
+
+/* Search bitmap for a set bit in backward direction from the end to the
+ * beginning of given region
+ *
+ * @result: result offset of the last set bit
+ * @addr:   base memory address,
+ * @low_off:  low end of the search region, edge bit included into the region,
+ * @high_off: high end of the search region, edge bit included into the region,
+ *
+ * @return: 0 - set bit was found, -1 otherwise.
+ */
+static int
+reiser4_find_last_set_bit(bmap_off_t * result, void *addr, bmap_off_t low_off,
+                         bmap_off_t high_off)
+{
+       ulong_t *base = addr;
+       int last_word;
+       int first_word;
+       int last_bit;
+       int nr;
+
+       assert("zam-962", high_off >= low_off);
+
+       last_word = high_off >> LONG_INT_SHIFT;
+       last_bit = high_off & LONG_INT_MASK;
+       first_word = low_off >> LONG_INT_SHIFT;
+
+       if (last_bit < BITS_PER_LONG) {
+               nr = find_last_set_bit_in_word(base[last_word], last_bit);
+               if (nr < BITS_PER_LONG) {
+                       *result = (last_word << LONG_INT_SHIFT) + nr;
+                       return 0;
+               }
+               --last_word;
+       }
+       while (last_word >= first_word) {
+               if (base[last_word] != 0x0) {
+                       last_bit =
+                           find_last_set_bit_in_word(base[last_word],
+                                                     BITS_PER_LONG - 1);
+                       assert("zam-972", last_bit < BITS_PER_LONG);
+                       *result = (last_word << LONG_INT_SHIFT) + last_bit;
+                       return 0;
+               }
+               --last_word;
+       }
+
+       return -1;              /* set bit not found */
+}
+
+/* Search bitmap for a clear bit in backward direction from the end to the
+ * beginning of given region */
+static int
+reiser4_find_last_zero_bit(bmap_off_t * result, void *addr, bmap_off_t low_off,
+                          bmap_off_t high_off)
+{
+       ulong_t *base = addr;
+       int last_word;
+       int first_word;
+       int last_bit;
+       int nr;
+
+       last_word = high_off >> LONG_INT_SHIFT;
+       last_bit = high_off & LONG_INT_MASK;
+       first_word = low_off >> LONG_INT_SHIFT;
+
+       if (last_bit < BITS_PER_LONG) {
+               nr = find_last_set_bit_in_word(~base[last_word], last_bit);
+               if (nr < BITS_PER_LONG) {
+                       *result = (last_word << LONG_INT_SHIFT) + nr;
+                       return 0;
+               }
+               --last_word;
+       }
+       while (last_word >= first_word) {
+               if (base[last_word] != (ulong_t) (-1)) {
+                       *result = (last_word << LONG_INT_SHIFT) +
+                           find_last_set_bit_in_word(~base[last_word],
+                                                     BITS_PER_LONG - 1);
+                       return 0;
+               }
+               --last_word;
+       }
+
+       return -1;              /* zero bit not found */
+}
+
+/* Audited by: green(2002.06.12) */
+static void reiser4_clear_bits(char *addr, bmap_off_t start, bmap_off_t end)
+{
+       int first_byte;
+       int last_byte;
+
+       unsigned char first_byte_mask = 0xFF;
+       unsigned char last_byte_mask = 0xFF;
+
+       assert("zam-410", start < end);
+
+       first_byte = start >> 3;
+       last_byte = (end - 1) >> 3;
+
+       if (last_byte > first_byte + 1)
+               memset(addr + first_byte + 1, 0,
+                      (size_t) (last_byte - first_byte - 1));
+
+       first_byte_mask >>= 8 - (start & 0x7);
+       last_byte_mask <<= ((end - 1) & 0x7) + 1;
+
+       if (first_byte == last_byte) {
+               addr[first_byte] &= (first_byte_mask | last_byte_mask);
+       } else {
+               addr[first_byte] &= first_byte_mask;
+               addr[last_byte] &= last_byte_mask;
+       }
+}
+
+/* Audited by: green(2002.06.12) */
+/* ZAM-FIXME-HANS: comment this */
+static void reiser4_set_bits(char *addr, bmap_off_t start, bmap_off_t end)
+{
+       int first_byte;
+       int last_byte;
+
+       unsigned char first_byte_mask = 0xFF;
+       unsigned char last_byte_mask = 0xFF;
+
+       assert("zam-386", start < end);
+
+       first_byte = start >> 3;
+       last_byte = (end - 1) >> 3;
+
+       if (last_byte > first_byte + 1)
+               memset(addr + first_byte + 1, 0xFF,
+                      (size_t) (last_byte - first_byte - 1));
+
+       first_byte_mask <<= start & 0x7;
+       last_byte_mask >>= 7 - ((end - 1) & 0x7);
+
+       if (first_byte == last_byte) {
+               addr[first_byte] |= (first_byte_mask & last_byte_mask);
+       } else {
+               addr[first_byte] |= first_byte_mask;
+               addr[last_byte] |= last_byte_mask;
+       }
+}
+
+#define ADLER_BASE    65521
+#define ADLER_NMAX    5552
+
+/* Calculates the adler32 checksum for the data pointed by `data` of the
+    length `len`. This function was originally taken from zlib, version 1.1.3,
+    July 9th, 1998.
+
+    Copyright (C) 1995-1998 Jean-loup Gailly and Mark Adler
+
+    This software is provided 'as-is', without any express or implied
+    warranty.  In no event will the authors be held liable for any damages
+    arising from the use of this software.
+
+    Permission is granted to anyone to use this software for any purpose,
+    including commercial applications, and to alter it and redistribute it
+    freely, subject to the following restrictions:
+
+    1. The origin of this software must not be misrepresented; you must not
+       claim that you wrote the original software. If you use this software
+       in a product, an acknowledgment in the product documentation would be
+       appreciated but is not required.
+    2. Altered source versions must be plainly marked as such, and must not be
+       misrepresented as being the original software.
+    3. This notice may not be removed or altered from any source distribution.
+
+    Jean-loup Gailly        Mark Adler
+    jloup@gzip.org          madler@alumni.caltech.edu
+
+    The above comment applies only to the reiser4_adler32 function.
+*/
+
+__u32 reiser4_adler32(char *data, __u32 len)
+{
+       unsigned char *t = data;
+       __u32 s1 = 1;
+       __u32 s2 = 0;
+       int k;
+
+       while (len > 0) {
+               k = len < ADLER_NMAX ? len : ADLER_NMAX;
+               len -= k;
+
+               while (k--) {
+                       s1 += *t++;
+                       s2 += s1;
+               }
+
+               s1 %= ADLER_BASE;
+               s2 %= ADLER_BASE;
+       }
+       return (s2 << 16) | s1;
+}
+
+#define sb_by_bnode(bnode) \
+       ((struct super_block *)jnode_get_tree(bnode->wjnode)->super)
+
+static __u32 bnode_calc_crc(const struct bitmap_node *bnode, unsigned long size)
+{
+       return reiser4_adler32(bnode_commit_data(bnode), bmap_size(size));
+}
+
+static int
+bnode_check_adler32(const struct bitmap_node *bnode, unsigned long size)
+{
+       if (bnode_calc_crc(bnode, size) != bnode_commit_crc(bnode)) {
+               bmap_nr_t bmap;
+
+               bmap = bnode - get_bnode(sb_by_bnode(bnode), 0);
+
+               warning("vpf-263",
+                       "Checksum for the bitmap block %llu is incorrect",
+                       bmap);
+
+               return RETERR(-EIO);
+       }
+
+       return 0;
+}
+
+#define REISER4_CHECK_BMAP_CRC (0)
+
+#if REISER4_CHECK_BMAP_CRC
+static int bnode_check_crc(const struct bitmap_node *bnode)
+{
+       return bnode_check_adler32(bnode,
+                                  bmap_size(sb_by_bnode(bnode)->s_blocksize));
+}
+
+/* REISER4_CHECK_BMAP_CRC */
+#else
+
+#define bnode_check_crc(bnode) (0)
+
+/* REISER4_CHECK_BMAP_CRC */
+#endif
+
+/* Recalculates the adler32 checksum for only 1 byte change.
+    adler - previous adler checksum
+    old_data, data - old, new byte values.
+    tail == (chunk - offset) : length, checksum was calculated for, - offset of
+    the changed byte within this chunk.
+    This function can be used for checksum calculation optimisation.
+*/
+
+static __u32
+adler32_recalc(__u32 adler, unsigned char old_data, unsigned char data,
+              __u32 tail)
+{
+       __u32 delta = data - old_data + 2 * ADLER_BASE;
+       __u32 s1 = adler & 0xffff;
+       __u32 s2 = (adler >> 16) & 0xffff;
+
+       s1 = (delta + s1) % ADLER_BASE;
+       s2 = (delta * tail + s2) % ADLER_BASE;
+
+       return (s2 << 16) | s1;
+}
+
+#define LIMIT(val, boundary) ((val) > (boundary) ? (boundary) : (val))
+
+/**
+ * get_nr_bitmap - calculate number of bitmap blocks
+ * @super: super block with initialized blocksize and block count
+ *
+ * Calculates number of bitmap blocks of a filesystem which uses bitmaps to
+ * maintain free disk space. It assumes that each bitmap addresses the same
+ * number of blocks which is calculated by bmap_block_count macro defined in
+ * above. Number of blocks in the filesystem has to be initialized in reiser4
+ * private data of super block already so that it can be obtained via
+ * reiser4_block_count(). Unfortunately, number of blocks addressed by a bitmap
+ * is not power of 2 because 4 bytes are used for checksum. Therefore, we have
+ * to use special function to divide and modulo 64bits filesystem block
+ * counters.
+ *
+ * Example: suppose filesystem have 32768 blocks. Blocksize is 4096. Each bitmap
+ * block addresses (4096 - 4) * 8 = 32736 blocks. Number of bitmaps to address
+ * all 32768 blocks is calculated as (32768 - 1) / 32736 + 1 = 2.
+ */
+static bmap_nr_t get_nr_bmap(const struct super_block *super)
+{
+       u64 quotient;
+
+       assert("zam-393", reiser4_block_count(super) != 0);
+
+       quotient = reiser4_block_count(super) - 1;
+       do_div(quotient, bmap_bit_count(super->s_blocksize));
+       return quotient + 1;
+}
+
+/**
+ * parse_blocknr - calculate bitmap number and offset in it by block number
+ * @block: pointer to block number to calculate location in bitmap of
+ * @bmap: pointer where to store bitmap block number
+ * @offset: pointer where to store offset within bitmap block
+ *
+ * Calculates location of bit which is responsible for allocation/freeing of
+ * block @*block. That location is represented by bitmap block number and offset
+ * within that bitmap block.
+ */
+static void
+parse_blocknr(const reiser4_block_nr *block, bmap_nr_t *bmap,
+             bmap_off_t *offset)
+{
+       struct super_block *super = get_current_context()->super;
+       u64 quotient = *block;
+
+       *offset = do_div(quotient, bmap_bit_count(super->s_blocksize));
+       *bmap = quotient;
+
+       assert("zam-433", *bmap < get_nr_bmap(super));
+       assert("", *offset < bmap_bit_count(super->s_blocksize));
+}
+
+#if REISER4_DEBUG
+/* Audited by: green(2002.06.12) */
+static void
+check_block_range(const reiser4_block_nr * start, const reiser4_block_nr * len)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+
+       assert("zam-436", sb != NULL);
+
+       assert("zam-455", start != NULL);
+       assert("zam-437", *start != 0);
+       assert("zam-541", !reiser4_blocknr_is_fake(start));
+       assert("zam-441", *start < reiser4_block_count(sb));
+
+       if (len != NULL) {
+               assert("zam-438", *len != 0);
+               assert("zam-442", *start + *len <= reiser4_block_count(sb));
+       }
+}
+
+static void check_bnode_loaded(const struct bitmap_node *bnode)
+{
+       assert("zam-485", bnode != NULL);
+       assert("zam-483", jnode_page(bnode->wjnode) != NULL);
+       assert("zam-484", jnode_page(bnode->cjnode) != NULL);
+       assert("nikita-2820", jnode_is_loaded(bnode->wjnode));
+       assert("nikita-2821", jnode_is_loaded(bnode->cjnode));
+}
+
+#else
+
+#  define check_block_range(start, len) do { /* nothing */} while(0)
+#  define check_bnode_loaded(bnode)     do { /* nothing */} while(0)
+
+#endif
+
+/* modify bnode->first_zero_bit (if we free bits before); bnode should be
+   spin-locked */
+static inline void
+adjust_first_zero_bit(struct bitmap_node *bnode, bmap_off_t offset)
+{
+       if (offset < bnode->first_zero_bit)
+               bnode->first_zero_bit = offset;
+}
+
+/* return a physical disk address for logical bitmap number @bmap */
+/* FIXME-VS: this is somehow related to disk layout? */
+/* ZAM-FIXME-HANS: your answer is? Use not more than one function dereference
+ * per block allocation so that performance is not affected.  Probably this
+ * whole file should be considered part of the disk layout plugin, and other
+ * disk layouts can use other defines and efficiency will not be significantly
+ * affected.  */
+
+#define REISER4_FIRST_BITMAP_BLOCK \
+       ((REISER4_MASTER_OFFSET / PAGE_CACHE_SIZE) + 2)
+
+/* Audited by: green(2002.06.12) */
+static void
+get_bitmap_blocknr(struct super_block *super, bmap_nr_t bmap,
+                  reiser4_block_nr * bnr)
+{
+
+       assert("zam-390", bmap < get_nr_bmap(super));
+
+#ifdef CONFIG_REISER4_BADBLOCKS
+#define BITMAP_PLUGIN_DISKMAP_ID ((0xc0e1<<16) | (0xe0ff))
+       /* Check if the diskmap have this already, first. */
+       if (reiser4_get_diskmap_value(BITMAP_PLUGIN_DISKMAP_ID, bmap, bnr) == 0)
+               return;         /* Found it in diskmap */
+#endif
+       /* FIXME_ZAM: before discussing of disk layouts and disk format
+          plugins I implement bitmap location scheme which is close to scheme
+          used in reiser 3.6 */
+       if (bmap == 0) {
+               *bnr = REISER4_FIRST_BITMAP_BLOCK;
+       } else {
+               *bnr = bmap * bmap_bit_count(super->s_blocksize);
+       }
+}
+
+/* construct a fake block number for shadow bitmap (WORKING BITMAP) block */
+/* Audited by: green(2002.06.12) */
+static void get_working_bitmap_blocknr(bmap_nr_t bmap, reiser4_block_nr * bnr)
+{
+       *bnr =
+           (reiser4_block_nr) ((bmap & ~REISER4_BLOCKNR_STATUS_BIT_MASK) |
+                               REISER4_BITMAP_BLOCKS_STATUS_VALUE);
+}
+
+/* bnode structure initialization */
+static void
+init_bnode(struct bitmap_node *bnode,
+          struct super_block *super UNUSED_ARG, bmap_nr_t bmap UNUSED_ARG)
+{
+       memset(bnode, 0, sizeof(struct bitmap_node));
+
+       mutex_init(&bnode->mutex);
+       atomic_set(&bnode->loaded, 0);
+}
+
+static void release(jnode * node)
+{
+       jrelse(node);
+       JF_SET(node, JNODE_HEARD_BANSHEE);
+       jput(node);
+}
+
+/* This function is for internal bitmap.c use because it assumes that jnode is
+   in under full control of this thread */
+static void done_bnode(struct bitmap_node *bnode)
+{
+       if (bnode) {
+               atomic_set(&bnode->loaded, 0);
+               if (bnode->wjnode != NULL)
+                       release(bnode->wjnode);
+               if (bnode->cjnode != NULL)
+                       release(bnode->cjnode);
+               bnode->wjnode = bnode->cjnode = NULL;
+       }
+}
+
+/* ZAM-FIXME-HANS: comment this.  Called only by load_and_lock_bnode()*/
+static int prepare_bnode(struct bitmap_node *bnode, jnode **cjnode_ret,
+                        jnode **wjnode_ret)
+{
+       struct super_block *super;
+       jnode *cjnode;
+       jnode *wjnode;
+       bmap_nr_t bmap;
+       int ret;
+
+       super = reiser4_get_current_sb();
+
+       *wjnode_ret = wjnode = bnew();
+       if (wjnode == NULL) {
+               *cjnode_ret = NULL;
+               return RETERR(-ENOMEM);
+       }
+
+       *cjnode_ret = cjnode = bnew();
+       if (cjnode == NULL)
+               return RETERR(-ENOMEM);
+
+       bmap = bnode - get_bnode(super, 0);
+
+       get_working_bitmap_blocknr(bmap, &wjnode->blocknr);
+       get_bitmap_blocknr(super, bmap, &cjnode->blocknr);
+
+       jref(cjnode);
+       jref(wjnode);
+
+       /* load commit bitmap */
+       ret = jload_gfp(cjnode, GFP_NOFS, 1);
+
+       if (ret)
+               goto error;
+
+       /* allocate memory for working bitmap block. Note that for
+        * bitmaps jinit_new() doesn't actually modifies node content,
+        * so parallel calls to this are ok. */
+       ret = jinit_new(wjnode, GFP_NOFS);
+
+       if (ret != 0) {
+               jrelse(cjnode);
+               goto error;
+       }
+
+       return 0;
+
+      error:
+       jput(cjnode);
+       jput(wjnode);
+       *wjnode_ret = *cjnode_ret = NULL;
+       return ret;
+
+}
+
+/* Check the bnode data on read. */
+static int check_struct_bnode(struct bitmap_node *bnode, __u32 blksize)
+{
+       void *data;
+       int ret;
+
+       /* Check CRC */
+       ret = bnode_check_adler32(bnode, blksize);
+
+       if (ret) {
+               return ret;
+       }
+
+       data = jdata(bnode->cjnode) + CHECKSUM_SIZE;
+
+       /* Check the very first bit -- it must be busy. */
+       if (!reiser4_test_bit(0, data)) {
+               warning("vpf-1362", "The allocator block %llu is not marked "
+                       "as used.", (unsigned long long)bnode->cjnode->blocknr);
+
+               return -EINVAL;
+       }
+
+       return 0;
+}
+
+/* load bitmap blocks "on-demand" */
+static int load_and_lock_bnode(struct bitmap_node *bnode)
+{
+       int ret;
+
+       jnode *cjnode;
+       jnode *wjnode;
+
+       assert("nikita-3040", reiser4_schedulable());
+
+/* ZAM-FIXME-HANS: since bitmaps are never unloaded, this does not
+ * need to be atomic, right? Just leave a comment that if bitmaps were
+ * unloadable, this would need to be atomic.  */
+       if (atomic_read(&bnode->loaded)) {
+               /* bitmap is already loaded, nothing to do */
+               check_bnode_loaded(bnode);
+               mutex_lock(&bnode->mutex);
+               assert("nikita-2827", atomic_read(&bnode->loaded));
+               return 0;
+       }
+
+       ret = prepare_bnode(bnode, &cjnode, &wjnode);
+       if (ret == 0) {
+               mutex_lock(&bnode->mutex);
+
+               if (!atomic_read(&bnode->loaded)) {
+                       assert("nikita-2822", cjnode != NULL);
+                       assert("nikita-2823", wjnode != NULL);
+                       assert("nikita-2824", jnode_is_loaded(cjnode));
+                       assert("nikita-2825", jnode_is_loaded(wjnode));
+
+                       bnode->wjnode = wjnode;
+                       bnode->cjnode = cjnode;
+
+                       ret = check_struct_bnode(bnode, current_blocksize);
+                       if (!ret) {
+                               cjnode = wjnode = NULL;
+                               atomic_set(&bnode->loaded, 1);
+                               /* working bitmap is initialized by on-disk
+                                * commit bitmap. This should be performed
+                                * under mutex. */
+                               memcpy(bnode_working_data(bnode),
+                                      bnode_commit_data(bnode),
+                                      bmap_size(current_blocksize));
+                       } else
+                               mutex_unlock(&bnode->mutex);
+               } else
+                       /* race: someone already loaded bitmap while we were
+                        * busy initializing data. */
+                       check_bnode_loaded(bnode);
+       }
+
+       if (wjnode != NULL) {
+               release(wjnode);
+               bnode->wjnode = NULL;
+       }
+       if (cjnode != NULL) {
+               release(cjnode);
+               bnode->cjnode = NULL;
+       }
+
+       return ret;
+}
+
+static void release_and_unlock_bnode(struct bitmap_node *bnode)
+{
+       check_bnode_loaded(bnode);
+       mutex_unlock(&bnode->mutex);
+}
+
+/* This function does all block allocation work but only for one bitmap
+   block.*/
+/* FIXME_ZAM: It does not allow us to allocate block ranges across bitmap
+   block responsibility zone boundaries. This had no sense in v3.6 but may
+   have it in v4.x */
+/* ZAM-FIXME-HANS: do you mean search one bitmap block forward? */
+static int
+search_one_bitmap_forward(bmap_nr_t bmap, bmap_off_t * offset,
+                         bmap_off_t max_offset, int min_len, int max_len)
+{
+       struct super_block *super = get_current_context()->super;
+       struct bitmap_node *bnode = get_bnode(super, bmap);
+
+       char *data;
+
+       bmap_off_t search_end;
+       bmap_off_t start;
+       bmap_off_t end;
+
+       int set_first_zero_bit = 0;
+
+       int ret;
+
+       assert("zam-364", min_len > 0);
+       assert("zam-365", max_len >= min_len);
+       assert("zam-366", *offset <= max_offset);
+
+       ret = load_and_lock_bnode(bnode);
+
+       if (ret)
+               return ret;
+
+       data = bnode_working_data(bnode);
+
+       start = *offset;
+
+       if (bnode->first_zero_bit >= start) {
+               start = bnode->first_zero_bit;
+               set_first_zero_bit = 1;
+       }
+
+       while (start + min_len < max_offset) {
+
+               start =
+                   reiser4_find_next_zero_bit((long *)data, max_offset, start);
+               if (set_first_zero_bit) {
+                       bnode->first_zero_bit = start;
+                       set_first_zero_bit = 0;
+               }
+               if (start >= max_offset)
+                       break;
+
+               search_end = LIMIT(start + max_len, max_offset);
+               end =
+                   reiser4_find_next_set_bit((long *)data, search_end, start);
+               if (end >= start + min_len) {
+                       /* we can't trust find_next_set_bit result if set bit
+                          was not fount, result may be bigger than
+                          max_offset */
+                       if (end > search_end)
+                               end = search_end;
+
+                       ret = end - start;
+                       *offset = start;
+
+                       reiser4_set_bits(data, start, end);
+
+                       /* FIXME: we may advance first_zero_bit if [start,
+                          end] region overlaps the first_zero_bit point */
+
+                       break;
+               }
+
+               start = end + 1;
+       }
+
+       release_and_unlock_bnode(bnode);
+
+       return ret;
+}
+
+static int
+search_one_bitmap_backward(bmap_nr_t bmap, bmap_off_t * start_offset,
+                          bmap_off_t end_offset, int min_len, int max_len)
+{
+       struct super_block *super = get_current_context()->super;
+       struct bitmap_node *bnode = get_bnode(super, bmap);
+       char *data;
+       bmap_off_t start;
+       int ret;
+
+       assert("zam-958", min_len > 0);
+       assert("zam-959", max_len >= min_len);
+       assert("zam-960", *start_offset >= end_offset);
+
+       ret = load_and_lock_bnode(bnode);
+       if (ret)
+               return ret;
+
+       data = bnode_working_data(bnode);
+       start = *start_offset;
+
+       while (1) {
+               bmap_off_t end, search_end;
+
+               /* Find the beginning of the zero filled region */
+               if (reiser4_find_last_zero_bit(&start, data, end_offset, start))
+                       break;
+               /* Is there more than `min_len' bits from `start' to
+                * `end_offset'?  */
+               if (start < end_offset + min_len - 1)
+                       break;
+
+               /* Do not search to `end_offset' if we need to find less than
+                * `max_len' zero bits. */
+               if (end_offset + max_len - 1 < start)
+                       search_end = start - max_len + 1;
+               else
+                       search_end = end_offset;
+
+               if (reiser4_find_last_set_bit(&end, data, search_end, start))
+                       end = search_end;
+               else
+                       end++;
+
+               if (end + min_len <= start + 1) {
+                       if (end < search_end)
+                               end = search_end;
+                       ret = start - end + 1;
+                       *start_offset = end;    /* `end' is lowest offset */
+                       assert("zam-987",
+                              reiser4_find_next_set_bit(data, start + 1,
+                                                        end) >= start + 1);
+                       reiser4_set_bits(data, end, start + 1);
+                       break;
+               }
+
+               if (end <= end_offset)
+                       /* left search boundary reached. */
+                       break;
+               start = end - 1;
+       }
+
+       release_and_unlock_bnode(bnode);
+       return ret;
+}
+
+/* allocate contiguous range of blocks in bitmap */
+static int bitmap_alloc_forward(reiser4_block_nr * start,
+                               const reiser4_block_nr * end, int min_len,
+                               int max_len)
+{
+       bmap_nr_t bmap, end_bmap;
+       bmap_off_t offset, end_offset;
+       int len;
+
+       reiser4_block_nr tmp;
+
+       struct super_block *super = get_current_context()->super;
+       const bmap_off_t max_offset = bmap_bit_count(super->s_blocksize);
+
+       parse_blocknr(start, &bmap, &offset);
+
+       tmp = *end - 1;
+       parse_blocknr(&tmp, &end_bmap, &end_offset);
+       ++end_offset;
+
+       assert("zam-358", end_bmap >= bmap);
+       assert("zam-359", ergo(end_bmap == bmap, end_offset >= offset));
+
+       for (; bmap < end_bmap; bmap++, offset = 0) {
+               len =
+                   search_one_bitmap_forward(bmap, &offset, max_offset,
+                                             min_len, max_len);
+               if (len != 0)
+                       goto out;
+       }
+
+       len =
+           search_one_bitmap_forward(bmap, &offset, end_offset, min_len,
+                                     max_len);
+      out:
+       *start = bmap * max_offset + offset;
+       return len;
+}
+
+/* allocate contiguous range of blocks in bitmap (from @start to @end in
+ * backward direction) */
+static int bitmap_alloc_backward(reiser4_block_nr * start,
+                                const reiser4_block_nr * end, int min_len,
+                                int max_len)
+{
+       bmap_nr_t bmap, end_bmap;
+       bmap_off_t offset, end_offset;
+       int len;
+       struct super_block *super = get_current_context()->super;
+       const bmap_off_t max_offset = bmap_bit_count(super->s_blocksize);
+
+       parse_blocknr(start, &bmap, &offset);
+       parse_blocknr(end, &end_bmap, &end_offset);
+
+       assert("zam-961", end_bmap <= bmap);
+       assert("zam-962", ergo(end_bmap == bmap, end_offset <= offset));
+
+       for (; bmap > end_bmap; bmap--, offset = max_offset - 1) {
+               len =
+                   search_one_bitmap_backward(bmap, &offset, 0, min_len,
+                                              max_len);
+               if (len != 0)
+                       goto out;
+       }
+
+       len =
+           search_one_bitmap_backward(bmap, &offset, end_offset, min_len,
+                                      max_len);
+      out:
+       *start = bmap * max_offset + offset;
+       return len;
+}
+
+/* plugin->u.space_allocator.alloc_blocks() */
+static int alloc_blocks_forward(reiser4_blocknr_hint *hint, int needed,
+                               reiser4_block_nr *start, reiser4_block_nr *len)
+{
+       struct super_block *super = get_current_context()->super;
+       int actual_len;
+
+       reiser4_block_nr search_start;
+       reiser4_block_nr search_end;
+
+       assert("zam-398", super != NULL);
+       assert("zam-412", hint != NULL);
+       assert("zam-397", hint->blk <= reiser4_block_count(super));
+
+       if (hint->max_dist == 0)
+               search_end = reiser4_block_count(super);
+       else
+               search_end =
+                   LIMIT(hint->blk + hint->max_dist,
+                         reiser4_block_count(super));
+
+       /* We use @hint -> blk as a search start and search from it to the end
+          of the disk or in given region if @hint -> max_dist is not zero */
+       search_start = hint->blk;
+
+       actual_len =
+           bitmap_alloc_forward(&search_start, &search_end, 1, needed);
+
+       /* There is only one bitmap search if max_dist was specified or first
+          pass was from the beginning of the bitmap. We also do one pass for
+          scanning bitmap in backward direction. */
+       if (!(actual_len != 0 || hint->max_dist != 0 || search_start == 0)) {
+               /* next step is a scanning from 0 to search_start */
+               search_end = search_start;
+               search_start = 0;
+               actual_len =
+                   bitmap_alloc_forward(&search_start, &search_end, 1, needed);
+       }
+       if (actual_len == 0)
+               return RETERR(-ENOSPC);
+       if (actual_len < 0)
+               return RETERR(actual_len);
+       *len = actual_len;
+       *start = search_start;
+       return 0;
+}
+
+static int alloc_blocks_backward(reiser4_blocknr_hint * hint, int needed,
+                                reiser4_block_nr * start,
+                                reiser4_block_nr * len)
+{
+       reiser4_block_nr search_start;
+       reiser4_block_nr search_end;
+       int actual_len;
+
+       ON_DEBUG(struct super_block *super = reiser4_get_current_sb());
+
+       assert("zam-969", super != NULL);
+       assert("zam-970", hint != NULL);
+       assert("zam-971", hint->blk <= reiser4_block_count(super));
+
+       search_start = hint->blk;
+       if (hint->max_dist == 0 || search_start <= hint->max_dist)
+               search_end = 0;
+       else
+               search_end = search_start - hint->max_dist;
+
+       actual_len =
+           bitmap_alloc_backward(&search_start, &search_end, 1, needed);
+       if (actual_len == 0)
+               return RETERR(-ENOSPC);
+       if (actual_len < 0)
+               return RETERR(actual_len);
+       *len = actual_len;
+       *start = search_start;
+       return 0;
+}
+
+/* plugin->u.space_allocator.alloc_blocks() */
+int reiser4_alloc_blocks_bitmap(reiser4_space_allocator * allocator,
+                               reiser4_blocknr_hint * hint, int needed,
+                               reiser4_block_nr * start, reiser4_block_nr * len)
+{
+       if (hint->backward)
+               return alloc_blocks_backward(hint, needed, start, len);
+       return alloc_blocks_forward(hint, needed, start, len);
+}
+
+/* plugin->u.space_allocator.dealloc_blocks(). */
+/* It just frees blocks in WORKING BITMAP. Usually formatted an unformatted
+   nodes deletion is deferred until transaction commit.  However, deallocation
+   of temporary objects like wandered blocks and transaction commit records
+   requires immediate node deletion from WORKING BITMAP.*/
+void reiser4_dealloc_blocks_bitmap(reiser4_space_allocator * allocator,
+                                  reiser4_block_nr start, reiser4_block_nr len)
+{
+       struct super_block *super = reiser4_get_current_sb();
+
+       bmap_nr_t bmap;
+       bmap_off_t offset;
+
+       struct bitmap_node *bnode;
+       int ret;
+
+       assert("zam-468", len != 0);
+       check_block_range(&start, &len);
+
+       parse_blocknr(&start, &bmap, &offset);
+
+       assert("zam-469", offset + len <= bmap_bit_count(super->s_blocksize));
+
+       bnode = get_bnode(super, bmap);
+
+       assert("zam-470", bnode != NULL);
+
+       ret = load_and_lock_bnode(bnode);
+       assert("zam-481", ret == 0);
+
+       reiser4_clear_bits(bnode_working_data(bnode), offset,
+                          (bmap_off_t) (offset + len));
+
+       adjust_first_zero_bit(bnode, offset);
+
+       release_and_unlock_bnode(bnode);
+}
+
+/* plugin->u.space_allocator.check_blocks(). */
+void reiser4_check_blocks_bitmap(const reiser4_block_nr * start,
+                                const reiser4_block_nr * len, int desired)
+{
+#if REISER4_DEBUG
+       struct super_block *super = reiser4_get_current_sb();
+
+       bmap_nr_t bmap;
+       bmap_off_t start_offset;
+       bmap_off_t end_offset;
+
+       struct bitmap_node *bnode;
+       int ret;
+
+       assert("zam-622", len != NULL);
+       check_block_range(start, len);
+       parse_blocknr(start, &bmap, &start_offset);
+
+       end_offset = start_offset + *len;
+       assert("nikita-2214", end_offset <= bmap_bit_count(super->s_blocksize));
+
+       bnode = get_bnode(super, bmap);
+
+       assert("nikita-2215", bnode != NULL);
+
+       ret = load_and_lock_bnode(bnode);
+       assert("zam-626", ret == 0);
+
+       assert("nikita-2216", jnode_is_loaded(bnode->wjnode));
+
+       if (desired) {
+               assert("zam-623",
+                      reiser4_find_next_zero_bit(bnode_working_data(bnode),
+                                                 end_offset, start_offset)
+                      >= end_offset);
+       } else {
+               assert("zam-624",
+                      reiser4_find_next_set_bit(bnode_working_data(bnode),
+                                                end_offset, start_offset)
+                      >= end_offset);
+       }
+
+       release_and_unlock_bnode(bnode);
+#endif
+}
+
+/* conditional insertion of @node into atom's overwrite set  if it was not there */
+static void cond_add_to_overwrite_set(txn_atom * atom, jnode * node)
+{
+       assert("zam-546", atom != NULL);
+       assert("zam-547", atom->stage == ASTAGE_PRE_COMMIT);
+       assert("zam-548", node != NULL);
+
+       spin_lock_atom(atom);
+       spin_lock_jnode(node);
+
+       if (node->atom == NULL) {
+               JF_SET(node, JNODE_OVRWR);
+               insert_into_atom_ovrwr_list(atom, node);
+       } else {
+               assert("zam-549", node->atom == atom);
+       }
+
+       spin_unlock_jnode(node);
+       spin_unlock_atom(atom);
+}
+
+/* an actor which applies delete set to COMMIT bitmap pages and link modified
+   pages in a single-linked list */
+static int
+apply_dset_to_commit_bmap(txn_atom * atom, const reiser4_block_nr * start,
+                         const reiser4_block_nr * len, void *data)
+{
+
+       bmap_nr_t bmap;
+       bmap_off_t offset;
+       int ret;
+
+       long long *blocks_freed_p = data;
+
+       struct bitmap_node *bnode;
+
+       struct super_block *sb = reiser4_get_current_sb();
+
+       check_block_range(start, len);
+
+       parse_blocknr(start, &bmap, &offset);
+
+       /* FIXME-ZAM: we assume that all block ranges are allocated by this
+          bitmap-based allocator and each block range can't go over a zone of
+          responsibility of one bitmap block; same assumption is used in
+          other journal hooks in bitmap code. */
+       bnode = get_bnode(sb, bmap);
+       assert("zam-448", bnode != NULL);
+
+       /* it is safe to unlock atom with is in ASTAGE_PRE_COMMIT */
+       assert("zam-767", atom->stage == ASTAGE_PRE_COMMIT);
+       ret = load_and_lock_bnode(bnode);
+       if (ret)
+               return ret;
+
+       /* put bnode into atom's overwrite set */
+       cond_add_to_overwrite_set(atom, bnode->cjnode);
+
+       data = bnode_commit_data(bnode);
+
+       ret = bnode_check_crc(bnode);
+       if (ret != 0)
+               return ret;
+
+       if (len != NULL) {
+               /* FIXME-ZAM: a check that all bits are set should be there */
+               assert("zam-443",
+                      offset + *len <= bmap_bit_count(sb->s_blocksize));
+               reiser4_clear_bits(data, offset, (bmap_off_t) (offset + *len));
+
+               (*blocks_freed_p) += *len;
+       } else {
+               reiser4_clear_bit(offset, data);
+               (*blocks_freed_p)++;
+       }
+
+       bnode_set_commit_crc(bnode, bnode_calc_crc(bnode, sb->s_blocksize));
+
+       release_and_unlock_bnode(bnode);
+
+       return 0;
+}
+
+/* plugin->u.space_allocator.pre_commit_hook(). */
+/* It just applies transaction changes to fs-wide COMMIT BITMAP, hoping the
+   rest is done by transaction manager (allocate wandered locations for COMMIT
+   BITMAP blocks, copy COMMIT BITMAP blocks data). */
+/* Only one instance of this function can be running at one given time, because
+   only one transaction can be committed a time, therefore it is safe to access
+   some global variables without any locking */
+
+int reiser4_pre_commit_hook_bitmap(void)
+{
+       struct super_block *super = reiser4_get_current_sb();
+       txn_atom *atom;
+
+       long long blocks_freed = 0;
+
+       atom = get_current_atom_locked();
+       assert("zam-876", atom->stage == ASTAGE_PRE_COMMIT);
+       spin_unlock_atom(atom);
+
+       {                       /* scan atom's captured list and find all freshly allocated nodes,
+                                * mark corresponded bits in COMMIT BITMAP as used */
+               struct list_head *head = ATOM_CLEAN_LIST(atom);
+               jnode *node = list_entry(head->next, jnode, capture_link);
+
+               while (head != &node->capture_link) {
+                       /* we detect freshly allocated jnodes */
+                       if (JF_ISSET(node, JNODE_RELOC)) {
+                               int ret;
+                               bmap_nr_t bmap;
+
+                               bmap_off_t offset;
+                               bmap_off_t index;
+                               struct bitmap_node *bn;
+                               __u32 size = bmap_size(super->s_blocksize);
+                               __u32 crc;
+                               char byte;
+
+                               assert("zam-559", !JF_ISSET(node, JNODE_OVRWR));
+                               assert("zam-460",
+                                      !reiser4_blocknr_is_fake(&node->blocknr));
+
+                               parse_blocknr(&node->blocknr, &bmap, &offset);
+                               bn = get_bnode(super, bmap);
+
+                               index = offset >> 3;
+                               assert("vpf-276", index < size);
+
+                               ret = bnode_check_crc(bnode);
+                               if (ret != 0)
+                                       return ret;
+
+                               check_bnode_loaded(bn);
+                               load_and_lock_bnode(bn);
+
+                               byte = *(bnode_commit_data(bn) + index);
+                               reiser4_set_bit(offset, bnode_commit_data(bn));
+
+                               crc = adler32_recalc(bnode_commit_crc(bn), byte,
+                                                    *(bnode_commit_data(bn) +
+                                                      index),
+                                                    size - index),
+                                   bnode_set_commit_crc(bn, crc);
+
+                               release_and_unlock_bnode(bn);
+
+                               ret = bnode_check_crc(bn);
+                               if (ret != 0)
+                                       return ret;
+
+                               /* working of this depends on how it inserts
+                                  new j-node into clean list, because we are
+                                  scanning the same list now. It is OK, if
+                                  insertion is done to the list front */
+                               cond_add_to_overwrite_set(atom, bn->cjnode);
+                       }
+
+                       node = list_entry(node->capture_link.next, jnode, capture_link);
+               }
+       }
+
+       blocknr_set_iterator(atom, &atom->delete_set, apply_dset_to_commit_bmap,
+                            &blocks_freed, 0);
+
+       blocks_freed -= atom->nr_blocks_allocated;
+
+       {
+               reiser4_super_info_data *sbinfo;
+
+               sbinfo = get_super_private(super);
+
+               spin_lock_reiser4_super(sbinfo);
+               sbinfo->blocks_free_committed += blocks_freed;
+               spin_unlock_reiser4_super(sbinfo);
+       }
+
+       return 0;
+}
+
+/* plugin->u.space_allocator.init_allocator
+    constructor of reiser4_space_allocator object. It is called on fs mount */
+int reiser4_init_allocator_bitmap(reiser4_space_allocator * allocator,
+                                 struct super_block *super, void *arg)
+{
+       struct bitmap_allocator_data *data = NULL;
+       bmap_nr_t bitmap_blocks_nr;
+       bmap_nr_t i;
+
+       assert("nikita-3039", reiser4_schedulable());
+
+       /* getting memory for bitmap allocator private data holder */
+       data =
+               kmalloc(sizeof(struct bitmap_allocator_data),
+                       reiser4_ctx_gfp_mask_get());
+
+       if (data == NULL)
+               return RETERR(-ENOMEM);
+
+       /* allocation and initialization for the array of bnodes */
+       bitmap_blocks_nr = get_nr_bmap(super);
+
+       /* FIXME-ZAM: it is not clear what to do with huge number of bitmaps
+          which is bigger than 2^32 (= 8 * 4096 * 4096 * 2^32 bytes = 5.76e+17,
+          may I never meet someone who still uses the ia32 architecture when
+          storage devices of that size enter the market, and wants to use ia32
+          with that storage device, much less reiser4. ;-) -Hans). Kmalloc is not possible and,
+          probably, another dynamic data structure should replace a static
+          array of bnodes. */
+       /*data->bitmap = reiser4_kmalloc((size_t) (sizeof (struct bitmap_node) * bitmap_blocks_nr), GFP_KERNEL); */
+       data->bitmap = reiser4_vmalloc(sizeof(struct bitmap_node) * bitmap_blocks_nr);
+       if (data->bitmap == NULL) {
+               kfree(data);
+               return RETERR(-ENOMEM);
+       }
+
+       for (i = 0; i < bitmap_blocks_nr; i++)
+               init_bnode(data->bitmap + i, super, i);
+
+       allocator->u.generic = data;
+
+#if REISER4_DEBUG
+       get_super_private(super)->min_blocks_used += bitmap_blocks_nr;
+#endif
+
+       /* Load all bitmap blocks at mount time. */
+       if (!test_bit
+           (REISER4_DONT_LOAD_BITMAP, &get_super_private(super)->fs_flags)) {
+               __u64 start_time, elapsed_time;
+               struct bitmap_node *bnode;
+               int ret;
+
+               if (REISER4_DEBUG)
+                       printk(KERN_INFO "loading reiser4 bitmap...");
+               start_time = jiffies;
+
+               for (i = 0; i < bitmap_blocks_nr; i++) {
+                       bnode = data->bitmap + i;
+                       ret = load_and_lock_bnode(bnode);
+                       if (ret) {
+                               reiser4_destroy_allocator_bitmap(allocator,
+                                                                super);
+                               return ret;
+                       }
+                       release_and_unlock_bnode(bnode);
+               }
+
+               elapsed_time = jiffies - start_time;
+               if (REISER4_DEBUG)
+                       printk("...done (%llu jiffies)\n",
+                              (unsigned long long)elapsed_time);
+       }
+
+       return 0;
+}
+
+/* plugin->u.space_allocator.destroy_allocator
+   destructor. It is called on fs unmount */
+int reiser4_destroy_allocator_bitmap(reiser4_space_allocator * allocator,
+                                    struct super_block *super)
+{
+       bmap_nr_t bitmap_blocks_nr;
+       bmap_nr_t i;
+
+       struct bitmap_allocator_data *data = allocator->u.generic;
+
+       assert("zam-414", data != NULL);
+       assert("zam-376", data->bitmap != NULL);
+
+       bitmap_blocks_nr = get_nr_bmap(super);
+
+       for (i = 0; i < bitmap_blocks_nr; i++) {
+               struct bitmap_node *bnode = data->bitmap + i;
+
+               mutex_lock(&bnode->mutex);
+
+#if REISER4_DEBUG
+               if (atomic_read(&bnode->loaded)) {
+                       jnode *wj = bnode->wjnode;
+                       jnode *cj = bnode->cjnode;
+
+                       assert("zam-480", jnode_page(cj) != NULL);
+                       assert("zam-633", jnode_page(wj) != NULL);
+
+                       assert("zam-634",
+                              memcmp(jdata(wj), jdata(wj),
+                                     bmap_size(super->s_blocksize)) == 0);
+
+               }
+#endif
+               done_bnode(bnode);
+               mutex_unlock(&bnode->mutex);
+       }
+
+       vfree(data->bitmap);
+       kfree(data);
+
+       allocator->u.generic = NULL;
+
+       return 0;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * scroll-step: 1
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/space/bitmap.h linux-2.6.20/fs/reiser4/plugin/space/bitmap.h
--- linux-2.6.20.orig/fs/reiser4/plugin/space/bitmap.h  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/space/bitmap.h       2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,47 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined (__REISER4_PLUGIN_SPACE_BITMAP_H__)
+#define __REISER4_PLUGIN_SPACE_BITMAP_H__
+
+#include "../../dformat.h"
+#include "../../block_alloc.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+/* EDWARD-FIXME-HANS: write something as informative as the below for every .h file lacking it. */
+/* declarations of functions implementing methods of space allocator plugin for
+   bitmap based allocator. The functions themselves are in bitmap.c */
+extern int reiser4_init_allocator_bitmap(reiser4_space_allocator *,
+                                        struct super_block *, void *);
+extern int reiser4_destroy_allocator_bitmap(reiser4_space_allocator *,
+                                           struct super_block *);
+extern int reiser4_alloc_blocks_bitmap(reiser4_space_allocator *,
+                                      reiser4_blocknr_hint *, int needed,
+                                      reiser4_block_nr * start,
+                                      reiser4_block_nr * len);
+extern void reiser4_check_blocks_bitmap(const reiser4_block_nr *,
+                                       const reiser4_block_nr *, int);
+extern void reiser4_dealloc_blocks_bitmap(reiser4_space_allocator *,
+                                         reiser4_block_nr,
+                                         reiser4_block_nr);
+extern int reiser4_pre_commit_hook_bitmap(void);
+
+#define reiser4_post_commit_hook_bitmap() do{}while(0)
+#define reiser4_post_write_back_hook_bitmap() do{}while(0)
+#define reiser4_print_info_bitmap(pref, al) do{}while(0)
+
+typedef __u64 bmap_nr_t;
+typedef __u32 bmap_off_t;
+
+#endif                         /* __REISER4_PLUGIN_SPACE_BITMAP_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/space/Makefile linux-2.6.20/fs/reiser4/plugin/space/Makefile
--- linux-2.6.20.orig/fs/reiser4/plugin/space/Makefile  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/space/Makefile       2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,4 @@
+obj-$(CONFIG_REISER4_FS) += space_plugins.o
+
+space_plugins-objs := \
+       bitmap.o
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/space/space_allocator.h linux-2.6.20/fs/reiser4/plugin/space/space_allocator.h
--- linux-2.6.20.orig/fs/reiser4/plugin/space/space_allocator.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/space/space_allocator.h      2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,80 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#ifndef __SPACE_ALLOCATOR_H__
+#define __SPACE_ALLOCATOR_H__
+
+#include "../../forward.h"
+#include "bitmap.h"
+/* NIKITA-FIXME-HANS: surely this could use a comment. Something about how bitmap is the only space allocator for now,
+ * but... */
+#define DEF_SPACE_ALLOCATOR(allocator)                                                                                 \
+                                                                                                                       \
+static inline int sa_init_allocator (reiser4_space_allocator * al, struct super_block *s, void * opaque)               \
+{                                                                                                                      \
+       return reiser4_init_allocator_##allocator (al, s, opaque);                                                      \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_destroy_allocator (reiser4_space_allocator *al, struct super_block *s)                           \
+{                                                                                                                      \
+       reiser4_destroy_allocator_##allocator (al, s);                                                                  \
+}                                                                                                                      \
+                                                                                                                       \
+static inline int sa_alloc_blocks (reiser4_space_allocator *al, reiser4_blocknr_hint * hint,                           \
+                                  int needed, reiser4_block_nr * start, reiser4_block_nr * len)                        \
+{                                                                                                                      \
+       return reiser4_alloc_blocks_##allocator (al, hint, needed, start, len);                                         \
+}                                                                                                                      \
+static inline void sa_dealloc_blocks (reiser4_space_allocator * al, reiser4_block_nr start, reiser4_block_nr len)      \
+{                                                                                                                      \
+       reiser4_dealloc_blocks_##allocator (al, start, len);                                                            \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_check_blocks (const reiser4_block_nr * start, const reiser4_block_nr * end, int desired)                 \
+{                                                                                                                      \
+       reiser4_check_blocks_##allocator (start, end, desired);                                                         \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_pre_commit_hook (void)                                                                           \
+{                                                                                                                      \
+       reiser4_pre_commit_hook_##allocator ();                                                                         \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_post_commit_hook (void)                                                                          \
+{                                                                                                                      \
+       reiser4_post_commit_hook_##allocator ();                                                                        \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_post_write_back_hook (void)                                                                      \
+{                                                                                                                      \
+       reiser4_post_write_back_hook_##allocator();                                                                     \
+}                                                                                                                      \
+                                                                                                                       \
+static inline void sa_print_info(const char * prefix, reiser4_space_allocator * al)                                    \
+{                                                                                                                      \
+       reiser4_print_info_##allocator (prefix, al);                                                                    \
+}
+
+DEF_SPACE_ALLOCATOR(bitmap)
+
+/* this object is part of reiser4 private in-core super block */
+struct reiser4_space_allocator {
+       union {
+               /* space allocators might use this pointer to reference their
+                * data. */
+               void *generic;
+       } u;
+};
+
+/* __SPACE_ALLOCATOR_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/plugin/tail_policy.c linux-2.6.20/fs/reiser4/plugin/tail_policy.c
--- linux-2.6.20.orig/fs/reiser4/plugin/tail_policy.c   1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/plugin/tail_policy.c        2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,113 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Formatting policy plugins */
+
+/*
+ * Formatting policy plugin is used by object plugin (of regular file) to
+ * convert file between two representations.
+ *
+ * Currently following policies are implemented:
+ *  never store file in formatted nodes
+ *  always store file in formatted nodes
+ *  store file in formatted nodes if file is smaller than 4 blocks (default)
+ */
+
+#include "../tree.h"
+#include "../inode.h"
+#include "../super.h"
+#include "object.h"
+#include "plugin.h"
+#include "node/node.h"
+#include "plugin_header.h"
+
+#include <linux/pagemap.h>
+#include <linux/fs.h>          /* For struct inode */
+
+/**
+ * have_formatting_never -
+ * @inode:
+ * @size:
+ *
+ *
+ */
+/* Never store file's tail as direct item */
+/* Audited by: green(2002.06.12) */
+static int have_formatting_never(const struct inode *inode UNUSED_ARG
+                     /* inode to operate on */ ,
+                     loff_t size UNUSED_ARG /* new object size */ )
+{
+       return 0;
+}
+
+/* Always store file's tail as direct item */
+/* Audited by: green(2002.06.12) */
+static int
+have_formatting_always(const struct inode *inode UNUSED_ARG
+                      /* inode to operate on */ ,
+                      loff_t size UNUSED_ARG /* new object size */ )
+{
+       return 1;
+}
+
+/* This function makes test if we should store file denoted @inode as tails only or
+   as extents only. */
+static int
+have_formatting_default(const struct inode *inode UNUSED_ARG
+                       /* inode to operate on */ ,
+                       loff_t size /* new object size */ )
+{
+       assert("umka-1253", inode != NULL);
+
+       if (size > inode->i_sb->s_blocksize * 4)
+               return 0;
+
+       return 1;
+}
+
+/* tail plugins */
+formatting_plugin formatting_plugins[LAST_TAIL_FORMATTING_ID] = {
+       [NEVER_TAILS_FORMATTING_ID] = {
+               .h = {
+                       .type_id = REISER4_FORMATTING_PLUGIN_TYPE,
+                       .id = NEVER_TAILS_FORMATTING_ID,
+                       .pops = NULL,
+                       .label = "never",
+                       .desc = "Never store file's tail",
+                       .linkage = {NULL, NULL}
+               },
+               .have_tail = have_formatting_never
+       },
+       [ALWAYS_TAILS_FORMATTING_ID] = {
+               .h = {
+                       .type_id = REISER4_FORMATTING_PLUGIN_TYPE,
+                       .id = ALWAYS_TAILS_FORMATTING_ID,
+                       .pops = NULL,
+                       .label = "always",
+                       .desc = "Always store file's tail",
+                       .linkage = {NULL, NULL}
+               },
+               .have_tail = have_formatting_always
+       },
+       [SMALL_FILE_FORMATTING_ID] = {
+               .h = {
+                       .type_id = REISER4_FORMATTING_PLUGIN_TYPE,
+                       .id = SMALL_FILE_FORMATTING_ID,
+                       .pops = NULL,
+                       .label = "4blocks",
+                       .desc = "store files shorter than 4 blocks in tail items",
+                       .linkage = {NULL, NULL}
+               },
+               .have_tail = have_formatting_default
+       }
+};
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/pool.c linux-2.6.20/fs/reiser4/pool.c
--- linux-2.6.20.orig/fs/reiser4/pool.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/pool.c      2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,234 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Fast pool allocation.
+
+   There are situations when some sub-system normally asks memory allocator
+   for only few objects, but under some circumstances could require much
+   more. Typical and actually motivating example is tree balancing. It needs
+   to keep track of nodes that were involved into it, and it is well-known
+   that in reasonable packed balanced tree most (92.938121%) percent of all
+   balancings end up after working with only few nodes (3.141592 on
+   average). But in rare cases balancing can involve much more nodes
+   (3*tree_height+1 in extremal situation).
+
+   On the one hand, we don't want to resort to dynamic allocation (slab,
+    malloc(), etc.) to allocate data structures required to keep track of
+   nodes during balancing. On the other hand, we cannot statically allocate
+   required amount of space on the stack, because first: it is useless wastage
+   of precious resource, and second: this amount is unknown in advance (tree
+   height can change).
+
+   Pools, implemented in this file are solution for this problem:
+
+    - some configurable amount of objects is statically preallocated on the
+    stack
+
+    - if this preallocated pool is exhausted and more objects is requested
+    they are allocated dynamically.
+
+   Pools encapsulate distinction between statically and dynamically allocated
+   objects. Both allocation and recycling look exactly the same.
+
+   To keep track of dynamically allocated objects, pool adds its own linkage
+   to each object.
+
+   NOTE-NIKITA This linkage also contains some balancing-specific data. This
+   is not perfect. On the other hand, balancing is currently the only client
+   of pool code.
+
+   NOTE-NIKITA Another desirable feature is to rewrite all pool manipulation
+   functions in the style of tslist/tshash, i.e., make them unreadable, but
+   type-safe.
+
+*/
+
+#include "debug.h"
+#include "pool.h"
+#include "super.h"
+
+#include <linux/types.h>
+#include <linux/err.h>
+
+/* initialize new pool object */
+static void reiser4_init_pool_obj(reiser4_pool_header * h      /* pool object to
+                                                                * initialize */ )
+{
+       INIT_LIST_HEAD(&h->usage_linkage);
+       INIT_LIST_HEAD(&h->level_linkage);
+       INIT_LIST_HEAD(&h->extra_linkage);
+}
+
+/* initialize new pool */
+void reiser4_init_pool(reiser4_pool * pool /* pool to initialize */ ,
+                      size_t obj_size /* size of objects in @pool */ ,
+                      int num_of_objs /* number of preallocated objects */ ,
+                      char *data /* area for preallocated objects */ )
+{
+       reiser4_pool_header *h;
+       int i;
+
+       assert("nikita-955", pool != NULL);
+       assert("nikita-1044", obj_size > 0);
+       assert("nikita-956", num_of_objs >= 0);
+       assert("nikita-957", data != NULL);
+
+       memset(pool, 0, sizeof *pool);
+       pool->obj_size = obj_size;
+       pool->data = data;
+       INIT_LIST_HEAD(&pool->free);
+       INIT_LIST_HEAD(&pool->used);
+       INIT_LIST_HEAD(&pool->extra);
+       memset(data, 0, obj_size * num_of_objs);
+       for (i = 0; i < num_of_objs; ++i) {
+               h = (reiser4_pool_header *) (data + i * obj_size);
+               reiser4_init_pool_obj(h);
+               /* add pool header to the end of pool's free list */
+               list_add_tail(&h->usage_linkage, &pool->free);
+       }
+}
+
+/* release pool resources
+
+   Release all resources acquired by this pool, specifically, dynamically
+   allocated objects.
+
+*/
+void reiser4_done_pool(reiser4_pool * pool UNUSED_ARG /* pool to destroy */ )
+{
+}
+
+/* allocate carry object from pool
+
+   First, try to get preallocated object. If this fails, resort to dynamic
+   allocation.
+
+*/
+static void *reiser4_pool_alloc(reiser4_pool * pool    /* pool to allocate object
+                                                        * from */ )
+{
+       reiser4_pool_header *result;
+
+       assert("nikita-959", pool != NULL);
+
+       if (!list_empty(&pool->free)) {
+               struct list_head *linkage;
+
+               linkage = pool->free.next;
+               list_del(linkage);
+               INIT_LIST_HEAD(linkage);
+               result = list_entry(linkage, reiser4_pool_header, usage_linkage);
+               BUG_ON(!list_empty(&result->level_linkage) ||
+                      !list_empty(&result->extra_linkage));
+       } else {
+               /* pool is empty. Extra allocations don't deserve dedicated
+                  slab to be served from, as they are expected to be rare. */
+               result = kmalloc(pool->obj_size, reiser4_ctx_gfp_mask_get());
+               if (result != 0) {
+                       reiser4_init_pool_obj(result);
+                       list_add(&result->extra_linkage, &pool->extra);
+               } else
+                       return ERR_PTR(RETERR(-ENOMEM));
+               BUG_ON(!list_empty(&result->usage_linkage) ||
+                      !list_empty(&result->level_linkage));
+       }
+       ++pool->objs;
+       list_add(&result->usage_linkage, &pool->used);
+       memset(result + 1, 0, pool->obj_size - sizeof *result);
+       return result;
+}
+
+/* return object back to the pool */
+void reiser4_pool_free(reiser4_pool * pool, reiser4_pool_header * h    /* pool to return object back
+                                                                        * into */ )
+{
+       assert("nikita-961", h != NULL);
+       assert("nikita-962", pool != NULL);
+
+       --pool->objs;
+       assert("nikita-963", pool->objs >= 0);
+
+       list_del_init(&h->usage_linkage);
+       list_del_init(&h->level_linkage);
+
+       if (list_empty(&h->extra_linkage))
+               /*
+                * pool header is not an extra one. Push it onto free list
+                * using usage_linkage
+                */
+               list_add(&h->usage_linkage, &pool->free);
+       else {
+               /* remove pool header from pool's extra list and kfree it */
+               list_del(&h->extra_linkage);
+               kfree(h);
+       }
+}
+
+/* add new object to the carry level list
+
+   Carry level is FIFO most of the time, but not always. Complications arise
+   when make_space() function tries to go to the left neighbor and thus adds
+   carry node before existing nodes, and also, when updating delimiting keys
+   after moving data between two nodes, we want left node to be locked before
+   right node.
+
+   Latter case is confusing at the first glance. Problem is that COP_UPDATE
+   opration that updates delimiting keys is sometimes called with two nodes
+   (when data are moved between two nodes) and sometimes with only one node
+   (when leftmost item is deleted in a node). In any case operation is
+   supplied with at least node whose left delimiting key is to be updated
+   (that is "right" node).
+
+*/
+reiser4_pool_header *reiser4_add_obj(reiser4_pool * pool /* pool from which to
+                                                         * allocate new object
+                                                         */,
+                                    struct list_head *list /* list where to add
+                                                            * object */,
+                                    pool_ordering order /* where to add */,
+                                    reiser4_pool_header * reference
+                                    /* after (or before) which existing object
+                                       to add */)
+{
+       reiser4_pool_header *result;
+
+       assert("nikita-972", pool != NULL);
+
+       result = reiser4_pool_alloc(pool);
+       if (IS_ERR(result))
+               return result;
+
+       assert("nikita-973", result != NULL);
+
+       switch (order) {
+       case POOLO_BEFORE:
+               __list_add(&result->level_linkage,
+                          reference->level_linkage.prev,
+                          &reference->level_linkage);
+               break;
+       case POOLO_AFTER:
+               __list_add(&result->level_linkage,
+                          &reference->level_linkage,
+                          reference->level_linkage.next);
+               break;
+       case POOLO_LAST:
+               list_add_tail(&result->level_linkage, list);
+               break;
+       case POOLO_FIRST:
+               list_add(&result->level_linkage, list);
+               break;
+       default:
+               wrong_return_value("nikita-927", "order");
+       }
+       return result;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/pool.h linux-2.6.20/fs/reiser4/pool.h
--- linux-2.6.20.orig/fs/reiser4/pool.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/pool.h      2007-05-06 14:50:43.863026968 +0400
@@ -0,0 +1,55 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Fast pool allocation */
+
+#ifndef __REISER4_POOL_H__
+#define __REISER4_POOL_H__
+
+#include <linux/types.h>
+
+typedef struct reiser4_pool {
+       size_t obj_size;
+       int objs;
+       char *data;
+       struct list_head free;
+       struct list_head used;
+       struct list_head extra;
+} reiser4_pool;
+
+typedef struct reiser4_pool_header {
+       /* object is either on free or "used" lists */
+       struct list_head usage_linkage;
+       struct list_head level_linkage;
+       struct list_head extra_linkage;
+} reiser4_pool_header;
+
+typedef enum {
+       POOLO_BEFORE,
+       POOLO_AFTER,
+       POOLO_LAST,
+       POOLO_FIRST
+} pool_ordering;
+
+/* pool manipulation functions */
+
+extern void reiser4_init_pool(reiser4_pool * pool, size_t obj_size,
+                             int num_of_objs, char *data);
+extern void reiser4_done_pool(reiser4_pool * pool);
+extern void reiser4_pool_free(reiser4_pool * pool, reiser4_pool_header * h);
+reiser4_pool_header *reiser4_add_obj(reiser4_pool * pool,
+                                    struct list_head * list,
+                                    pool_ordering order,
+                                    reiser4_pool_header * reference);
+
+/* __REISER4_POOL_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/readahead.c linux-2.6.20/fs/reiser4/readahead.c
--- linux-2.6.20.orig/fs/reiser4/readahead.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/readahead.c 2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,138 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "forward.h"
+#include "tree.h"
+#include "tree_walk.h"
+#include "super.h"
+#include "inode.h"
+#include "key.h"
+#include "znode.h"
+
+#include <linux/swap.h>                /* for totalram_pages */
+
+void reiser4_init_ra_info(ra_info_t * rai)
+{
+       rai->key_to_stop = *reiser4_min_key();
+}
+
+/* global formatted node readahead parameter. It can be set by mount option -o readahead:NUM:1 */
+static inline int ra_adjacent_only(int flags)
+{
+       return flags & RA_ADJACENT_ONLY;
+}
+
+/* this is used by formatted_readahead to decide whether read for right neighbor of node is to be issued. It returns 1
+   if right neighbor's first key is less or equal to readahead's stop key */
+static int should_readahead_neighbor(znode * node, ra_info_t * info)
+{
+       int result;
+
+       read_lock_dk(znode_get_tree(node));
+       result = keyle(znode_get_rd_key(node), &info->key_to_stop);
+       read_unlock_dk(znode_get_tree(node));
+       return result;
+}
+
+#define LOW_MEM_PERCENTAGE (5)
+
+static int low_on_memory(void)
+{
+       unsigned int freepages;
+
+       freepages = nr_free_pages();
+       return freepages < (totalram_pages * LOW_MEM_PERCENTAGE / 100);
+}
+
+/* start read for @node and for a few of its right neighbors */
+void formatted_readahead(znode * node, ra_info_t * info)
+{
+       ra_params_t *ra_params;
+       znode *cur;
+       int i;
+       int grn_flags;
+       lock_handle next_lh;
+
+       /* do nothing if node block number has not been assigned to node (which means it is still in cache). */
+       if (reiser4_blocknr_is_fake(znode_get_block(node)))
+               return;
+
+       ra_params = get_current_super_ra_params();
+
+       if (znode_page(node) == NULL)
+               jstartio(ZJNODE(node));
+
+       if (znode_get_level(node) != LEAF_LEVEL)
+               return;
+
+       /* don't waste memory for read-ahead when low on memory */
+       if (low_on_memory())
+               return;
+
+       /* We can have locked nodes on upper tree levels, in this situation lock
+          priorities do not help to resolve deadlocks, we have to use TRY_LOCK
+          here. */
+       grn_flags = (GN_CAN_USE_UPPER_LEVELS | GN_TRY_LOCK);
+
+       i = 0;
+       cur = zref(node);
+       init_lh(&next_lh);
+       while (i < ra_params->max) {
+               const reiser4_block_nr *nextblk;
+
+               if (!should_readahead_neighbor(cur, info))
+                       break;
+
+               if (reiser4_get_right_neighbor
+                   (&next_lh, cur, ZNODE_READ_LOCK, grn_flags))
+                       break;
+
+               nextblk = znode_get_block(next_lh.node);
+               if (reiser4_blocknr_is_fake(nextblk) ||
+                   (ra_adjacent_only(ra_params->flags)
+                    && *nextblk != *znode_get_block(cur) + 1)) {
+                       break;
+               }
+
+               zput(cur);
+               cur = zref(next_lh.node);
+               done_lh(&next_lh);
+               if (znode_page(cur) == NULL)
+                       jstartio(ZJNODE(cur));
+               else
+                       /* Do not scan read-ahead window if pages already
+                        * allocated (and i/o already started). */
+                       break;
+
+               i++;
+       }
+       zput(cur);
+       done_lh(&next_lh);
+}
+
+void reiser4_readdir_readahead_init(struct inode *dir, tap_t * tap)
+{
+       reiser4_key *stop_key;
+
+       assert("nikita-3542", dir != NULL);
+       assert("nikita-3543", tap != NULL);
+
+       stop_key = &tap->ra_info.key_to_stop;
+       /* initialize readdir readahead information: include into readahead
+        * stat data of all files of the directory */
+       set_key_locality(stop_key, get_inode_oid(dir));
+       set_key_type(stop_key, KEY_SD_MINOR);
+       set_key_ordering(stop_key, get_key_ordering(reiser4_max_key()));
+       set_key_objectid(stop_key, get_key_objectid(reiser4_max_key()));
+       set_key_offset(stop_key, get_key_offset(reiser4_max_key()));
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/readahead.h linux-2.6.20/fs/reiser4/readahead.h
--- linux-2.6.20.orig/fs/reiser4/readahead.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/readahead.h 2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,48 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#ifndef __READAHEAD_H__
+#define __READAHEAD_H__
+
+#include "key.h"
+
+typedef enum {
+       RA_ADJACENT_ONLY = 1,   /* only requests nodes which are adjacent. Default is NO (not only adjacent) */
+} ra_global_flags;
+
+/* reiser4 super block has a field of this type. It controls readahead during tree traversals */
+typedef struct formatted_read_ahead_params {
+       unsigned long max;      /* request not more than this amount of nodes. Default is totalram_pages / 4 */
+       int flags;
+} ra_params_t;
+
+typedef struct {
+       reiser4_key key_to_stop;
+} ra_info_t;
+
+void formatted_readahead(znode *, ra_info_t *);
+void reiser4_init_ra_info(ra_info_t * rai);
+
+struct reiser4_file_ra_state {
+       loff_t start;           /* Current window */
+       loff_t size;
+       loff_t next_size;       /* Next window size */
+       loff_t ahead_start;     /* Ahead window */
+       loff_t ahead_size;
+       loff_t max_window_size; /* Maximum readahead window */
+       loff_t slow_start;      /* enlarging r/a size algorithm. */
+};
+
+extern void reiser4_readdir_readahead_init(struct inode *dir, tap_t * tap);
+
+/* __READAHEAD_H__ */
+#endif
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/README linux-2.6.20/fs/reiser4/README
--- linux-2.6.20.orig/fs/reiser4/README 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/README      2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,125 @@
+[LICENSING]
+
+Reiser4 is hereby licensed under the GNU General
+Public License version 2.
+
+Source code files that contain the phrase "licensing governed by
+reiser4/README" are "governed files" throughout this file.  Governed
+files are licensed under the GPL.  The portions of them owned by Hans
+Reiser, or authorized to be licensed by him, have been in the past,
+and likely will be in the future, licensed to other parties under
+other licenses.  If you add your code to governed files, and don't
+want it to be owned by Hans Reiser, put your copyright label on that
+code so the poor blight and his customers can keep things straight.
+All portions of governed files not labeled otherwise are owned by Hans
+Reiser, and by adding your code to it, widely distributing it to
+others or sending us a patch, and leaving the sentence in stating that
+licensing is governed by the statement in this file, you accept this.
+It will be a kindness if you identify whether Hans Reiser is allowed
+to license code labeled as owned by you on your behalf other than
+under the GPL, because he wants to know if it is okay to do so and put
+a check in the mail to you (for non-trivial improvements) when he
+makes his next sale.  He makes no guarantees as to the amount if any,
+though he feels motivated to motivate contributors, and you can surely
+discuss this with him before or after contributing.  You have the
+right to decline to allow him to license your code contribution other
+than under the GPL.
+
+Further licensing options are available for commercial and/or other
+interests directly from Hans Reiser: reiser@namesys.com.  If you interpret
+the GPL as not allowing those additional licensing options, you read
+it wrongly, and Richard Stallman agrees with me, when carefully read
+you can see that those restrictions on additional terms do not apply
+to the owner of the copyright, and my interpretation of this shall
+govern for this license.
+
+[END LICENSING]
+
+Reiser4 is a file system based on dancing tree algorithms, and is
+described at http://www.namesys.com
+
+mkfs.reiser4 and other utilities are on our webpage or wherever your
+Linux provider put them.  You really want to be running the latest
+version off the website if you use fsck.
+
+Yes, if you update your reiser4 kernel module you do have to
+recompile your kernel, most of the time.  The errors you get will be
+quite cryptic if your forget to do so.
+
+Hideous Commercial Pitch: Spread your development costs across other OS
+vendors.  Select from the best in the world, not the best in your
+building, by buying from third party OS component suppliers.  Leverage
+the software component development power of the internet.  Be the most
+aggressive in taking advantage of the commercial possibilities of
+decentralized internet development, and add value through your branded
+integration that you sell as an operating system.  Let your competitors
+be the ones to compete against the entire internet by themselves.  Be
+hip, get with the new economic trend, before your competitors do.  Send
+email to reiser@namesys.com
+
+Hans Reiser was the primary architect of Reiser4, but a whole team
+chipped their ideas in.  He invested everything he had into Namesys
+for 5.5 dark years of no money before Reiser3 finally started to work well
+enough to bring in money.  He owns the copyright.
+
+DARPA was the primary sponsor of Reiser4.  DARPA does not endorse
+Reiser4, it merely sponsors it.  DARPA is, in solely Hans's personal
+opinion, unique in its willingness to invest into things more
+theoretical than the VC community can readily understand, and more
+longterm than allows them to be sure that they will be the ones to
+extract the economic benefits from.  DARPA also integrated us into a
+security community that transformed our security worldview.
+
+Vladimir Saveliev is our lead programmer, with us from the beginning,
+and he worked long hours writing the cleanest code.  This is why he is
+now the lead programmer after years of commitment to our work.  He
+always made the effort to be the best he could be, and to make his
+code the best that it could be.  What resulted was quite remarkable. I
+don't think that money can ever motivate someone to work the way he
+did, he is one of the most selfless men I know.
+
+Alexander Lyamin was our sysadmin, and helped to educate us in
+security issues.  Moscow State University and IMT were very generous
+in the internet access they provided us, and in lots of other little
+ways that a generous institution can be.
+
+Alexander Zarochentcev (sometimes known as zam, or sasha), wrote the
+locking code, the block allocator, and finished the flushing code.
+His code is always crystal clean and well structured.
+
+Nikita Danilov wrote the core of the balancing code, the core of the
+plugins code, and the directory code.  He worked a steady pace of long
+hours that produced a whole lot of well abstracted code.  He is our
+senior computer scientist.
+
+Vladimir Demidov wrote the parser.  Writing an in kernel parser is
+something very few persons have the skills for, and it is thanks to
+him that we can say that the parser is really not so big compared to
+various bits of our other code, and making a parser work in the kernel
+was not so complicated as everyone would imagine mainly because it was
+him doing it...
+
+Joshua McDonald wrote the transaction manager, and the flush code.
+The flush code unexpectedly turned out be extremely hairy for reasons
+you can read about on our web page, and he did a great job on an
+extremely difficult task.
+
+Nina Reiser handled our accounting, government relations, and much
+more.
+
+Ramon Reiser developed our website.
+
+Beverly Palmer drew our graphics.
+
+Vitaly Fertman developed librepair, userspace plugins repair code, fsck
+and worked with Umka on developing libreiser4 and userspace plugins.
+
+Yury Umanets (aka Umka) developed libreiser4, userspace plugins and
+userspace tools (reiser4progs).
+
+Oleg Drokin (aka Green) is the release manager who fixes everything.
+It is so nice to have someone like that on the team.  He (plus Chris
+and Jeff) make it possible for the entire rest of the Namesys team to
+focus on Reiser4, and he fixed a whole lot of Reiser4 bugs also.  It
+is just amazing to watch his talent for spotting bugs in action.
+
diff -urN linux-2.6.20.orig/fs/reiser4/reiser4.h linux-2.6.20/fs/reiser4/reiser4.h
--- linux-2.6.20.orig/fs/reiser4/reiser4.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/reiser4.h   2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,269 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* definitions of common constants used by reiser4 */
+
+#if !defined( __REISER4_H__ )
+#define __REISER4_H__
+
+#include <asm/param.h>         /* for HZ */
+#include <linux/errno.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/hardirq.h>
+#include <linux/sched.h>
+
+/*
+ * reiser4 compilation options.
+ */
+
+#if defined(CONFIG_REISER4_DEBUG)
+/* turn on assertion checks */
+#define REISER4_DEBUG (1)
+#else
+#define REISER4_DEBUG (0)
+#endif
+
+#if defined(CONFIG_ZLIB_INFLATE)
+/* turn on zlib */
+#define REISER4_ZLIB (1)
+#else
+#define REISER4_ZLIB (0)
+#endif
+
+#if defined(CONFIG_CRYPTO_SHA256)
+#define REISER4_SHA256 (1)
+#else
+#define REISER4_SHA256 (0)
+#endif
+
+/*
+ * Turn on large keys mode. In his mode (which is default), reiser4 key has 4
+ * 8-byte components. In the old "small key" mode, it's 3 8-byte
+ * components. Additional component, referred to as "ordering" is used to
+ * order items from which given object is composed of. As such, ordering is
+ * placed between locality and objectid. For directory item ordering contains
+ * initial prefix of the file name this item is for. This sorts all directory
+ * items within given directory lexicographically (but see
+ * fibration.[ch]). For file body and stat-data, ordering contains initial
+ * prefix of the name file was initially created with. In the common case
+ * (files with single name) this allows to order file bodies and stat-datas in
+ * the same order as their respective directory entries, thus speeding up
+ * readdir.
+ *
+ * Note, that kernel can only mount file system with the same key size as one
+ * it is compiled for, so flipping this option may render your data
+ * inaccessible.
+ */
+#define REISER4_LARGE_KEY (1)
+/*#define REISER4_LARGE_KEY (0)*/
+
+/*#define GUESS_EXISTS 1*/
+
+/*
+ * PLEASE update fs/reiser4/kattr.c:show_options() when adding new compilation
+ * option
+ */
+
+extern const char *REISER4_SUPER_MAGIC_STRING;
+extern const int REISER4_MAGIC_OFFSET; /* offset to magic string from the
+                                        * beginning of device */
+
+/* here go tunable parameters that are not worth special entry in kernel
+   configuration */
+
+/* default number of slots in coord-by-key caches */
+#define CBK_CACHE_SLOTS    (16)
+/* how many elementary tree operation to carry on the next level */
+#define CARRIES_POOL_SIZE        (5)
+/* size of pool of preallocated nodes for carry process. */
+#define NODES_LOCKED_POOL_SIZE   (5)
+
+#define REISER4_NEW_NODE_FLAGS (COPI_LOAD_LEFT | COPI_LOAD_RIGHT | COPI_GO_LEFT)
+#define REISER4_NEW_EXTENT_FLAGS (COPI_LOAD_LEFT | COPI_LOAD_RIGHT | COPI_GO_LEFT)
+#define REISER4_PASTE_FLAGS (COPI_GO_LEFT)
+#define REISER4_INSERT_FLAGS (COPI_GO_LEFT)
+
+/* we are supporting reservation of disk space on uid basis */
+#define REISER4_SUPPORT_UID_SPACE_RESERVATION (0)
+/* we are supporting reservation of disk space for groups */
+#define REISER4_SUPPORT_GID_SPACE_RESERVATION (0)
+/* we are supporting reservation of disk space for root */
+#define REISER4_SUPPORT_ROOT_SPACE_RESERVATION (0)
+/* we use rapid flush mode, see flush.c for comments.  */
+#define REISER4_USE_RAPID_FLUSH (1)
+
+/*
+ * set this to 0 if you don't want to use wait-for-flush in ->writepage().
+ */
+#define REISER4_USE_ENTD (1)
+
+/* key allocation is Plan-A */
+#define REISER4_PLANA_KEY_ALLOCATION (1)
+/* key allocation follows good old 3.x scheme */
+#define REISER4_3_5_KEY_ALLOCATION (0)
+
+/* size of hash-table for znodes */
+#define REISER4_ZNODE_HASH_TABLE_SIZE (1 << 13)
+
+/* number of buckets in lnode hash-table */
+#define LNODE_HTABLE_BUCKETS (1024)
+
+/* some ridiculously high maximal limit on height of znode tree. This
+    is used in declaration of various per level arrays and
+    to allocate stattistics gathering array for per-level stats. */
+#define REISER4_MAX_ZTREE_HEIGHT     (8)
+
+#define REISER4_PANIC_MSG_BUFFER_SIZE (1024)
+
+/* If array contains less than REISER4_SEQ_SEARCH_BREAK elements then,
+   sequential search is on average faster than binary. This is because
+   of better optimization and because sequential search is more CPU
+   cache friendly. This number (25) was found by experiments on dual AMD
+   Athlon(tm), 1400MHz.
+
+   NOTE: testing in kernel has shown that binary search is more effective than
+   implied by results of the user level benchmarking. Probably because in the
+   node keys are separated by other data. So value was adjusted after few
+   tests. More thorough tuning is needed.
+*/
+#define REISER4_SEQ_SEARCH_BREAK      (3)
+
+/* don't allow tree to be lower than this */
+#define REISER4_MIN_TREE_HEIGHT       (TWIG_LEVEL)
+
+/* NOTE NIKITA this is no longer used: maximal atom size is auto-adjusted to
+ * available memory. */
+/* Default value of maximal atom size. Can be ovewritten by
+   tmgr.atom_max_size mount option. By default infinity. */
+#define REISER4_ATOM_MAX_SIZE         ((unsigned)(~0))
+
+/* Default value of maximal atom age (in jiffies). After reaching this age
+   atom will be forced to commit, either synchronously or asynchronously. Can
+   be overwritten by tmgr.atom_max_age mount option. */
+#define REISER4_ATOM_MAX_AGE          (600 * HZ)
+
+/* sleeping period for ktxnmrgd */
+#define REISER4_TXNMGR_TIMEOUT  (5 * HZ)
+
+/* timeout to wait for ent thread in writepage. Default: 3 milliseconds. */
+#define REISER4_ENTD_TIMEOUT (3 * HZ / 1000)
+
+/* start complaining after that many restarts in coord_by_key().
+
+   This either means incredibly heavy contention for this part of a tree, or
+   some corruption or bug.
+*/
+#define REISER4_CBK_ITERATIONS_LIMIT  (100)
+
+/* return -EIO after that many iterations in coord_by_key().
+
+   I have witnessed more than 800 iterations (in 30 thread test) before cbk
+   finished. --nikita
+*/
+#define REISER4_MAX_CBK_ITERATIONS    500000
+
+/* put a per-inode limit on maximal number of directory entries with identical
+   keys in hashed directory.
+
+   Disable this until inheritance interfaces stabilize: we need some way to
+   set per directory limit.
+*/
+#define REISER4_USE_COLLISION_LIMIT    (0)
+
+/* If flush finds more than FLUSH_RELOCATE_THRESHOLD adjacent dirty leaf-level blocks it
+   will force them to be relocated. */
+#define FLUSH_RELOCATE_THRESHOLD 64
+/* If flush finds can find a block allocation closer than at most FLUSH_RELOCATE_DISTANCE
+   from the preceder it will relocate to that position. */
+#define FLUSH_RELOCATE_DISTANCE  64
+
+/* If we have written this much or more blocks before encountering busy jnode
+   in flush list - abort flushing hoping that next time we get called
+   this jnode will be clean already, and we will save some seeks. */
+#define FLUSH_WRITTEN_THRESHOLD 50
+
+/* The maximum number of nodes to scan left on a level during flush. */
+#define FLUSH_SCAN_MAXNODES 10000
+
+/* per-atom limit of flushers */
+#define ATOM_MAX_FLUSHERS (1)
+
+/* default tracing buffer size */
+#define REISER4_TRACE_BUF_SIZE (1 << 15)
+
+/* what size units of IO we would like cp, etc., to use, in writing to
+   reiser4. In bytes.
+
+   Can be overwritten by optimal_io_size mount option.
+*/
+#define REISER4_OPTIMAL_IO_SIZE (64 * 1024)
+
+/* see comments in inode.c:oid_to_uino() */
+#define REISER4_UINO_SHIFT (1 << 30)
+
+/* Mark function argument as unused to avoid compiler warnings. */
+#define UNUSED_ARG __attribute__((unused))
+
+#if ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 3)) || (__GNUC__ > 3)
+#define NONNULL __attribute__((nonnull))
+#else
+#define NONNULL
+#endif
+
+/* master super block offset in bytes.*/
+#define REISER4_MASTER_OFFSET 65536
+
+/* size of VFS block */
+#define VFS_BLKSIZE 512
+/* number of bits in size of VFS block (512==2^9) */
+#define VFS_BLKSIZE_BITS 9
+
+#define REISER4_I reiser4_inode_data
+
+/* implication */
+#define ergo( antecedent, consequent ) ( !( antecedent ) || ( consequent ) )
+/* logical equivalence */
+#define equi( p1, p2 ) ( ergo( ( p1 ), ( p2 ) ) && ergo( ( p2 ), ( p1 ) ) )
+
+#define sizeof_array(x) ((int) (sizeof(x) / sizeof(x[0])))
+
+#define NOT_YET                       (0)
+
+/** Reiser4 specific error codes **/
+
+#define REISER4_ERROR_CODE_BASE 500
+
+/* Neighbor is not available (side neighbor or parent) */
+#define E_NO_NEIGHBOR  (REISER4_ERROR_CODE_BASE)
+
+/* Node was not found in cache */
+#define E_NOT_IN_CACHE (REISER4_ERROR_CODE_BASE + 1)
+
+/* node has no free space enough for completion of balancing operation */
+#define E_NODE_FULL    (REISER4_ERROR_CODE_BASE + 2)
+
+/* repeat operation */
+#define E_REPEAT       (REISER4_ERROR_CODE_BASE + 3)
+
+/* deadlock happens */
+#define E_DEADLOCK     (REISER4_ERROR_CODE_BASE + 4)
+
+/* operation cannot be performed, because it would block and non-blocking mode
+ * was requested. */
+#define E_BLOCK        (REISER4_ERROR_CODE_BASE + 5)
+
+/* wait some event (depends on context), then repeat */
+#define E_WAIT         (REISER4_ERROR_CODE_BASE + 6)
+
+#endif                         /* __REISER4_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/safe_link.c linux-2.6.20/fs/reiser4/safe_link.c
--- linux-2.6.20.orig/fs/reiser4/safe_link.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/safe_link.c 2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,351 @@
+/* Copyright 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Safe-links. */
+
+/*
+ * Safe-links are used to maintain file system consistency during operations
+ * that spawns multiple transactions. For example:
+ *
+ *     1. Unlink. UNIX supports "open-but-unlinked" files, that is files
+ *     without user-visible names in the file system, but still opened by some
+ *     active process. What happens here is that unlink proper (i.e., removal
+ *     of the last file name) and file deletion (truncate of file body to zero
+ *     and deletion of stat-data, that happens when last file descriptor is
+ *     closed), may belong to different transactions T1 and T2. If a crash
+ *     happens after T1 commit, but before T2 commit, on-disk file system has
+ *     a file without name, that is, disk space leak.
+ *
+ *     2. Truncate. Truncate of large file may spawn multiple transactions. If
+ *     system crashes while truncate was in-progress, file is left partially
+ *     truncated, which violates "atomicity guarantees" of reiser4, viz. that
+ *     every system is atomic.
+ *
+ * Safe-links address both above cases. Basically, safe-link is a way post
+ * some operation to be executed during commit of some other transaction than
+ * current one. (Another way to look at the safe-link is to interpret it as a
+ * logical logging.)
+ *
+ * Specifically, at the beginning of unlink safe-link in inserted in the
+ * tree. This safe-link is normally removed by file deletion code (during
+ * transaction T2 in the above terms). Truncate also inserts safe-link that is
+ * normally removed when truncate operation is finished.
+ *
+ * This means, that in the case of "clean umount" there are no safe-links in
+ * the tree. If safe-links are observed during mount, it means that (a) system
+ * was terminated abnormally, and (b) safe-link correspond to the "pending"
+ * (i.e., not finished) operations that were in-progress during system
+ * termination. Each safe-link record enough information to complete
+ * corresponding operation, and mount simply "replays" them (hence, the
+ * analogy with the logical logging).
+ *
+ * Safe-links are implemented as blackbox items (see
+ * plugin/item/blackbox.[ch]).
+ *
+ * For the reference: ext3 also has similar mechanism, it's called "an orphan
+ * list" there.
+ */
+
+#include "safe_link.h"
+#include "debug.h"
+#include "inode.h"
+
+#include "plugin/item/blackbox.h"
+
+#include <linux/fs.h>
+
+/*
+ * On-disk format of safe-link.
+ */
+typedef struct safelink {
+       reiser4_key sdkey;      /* key of stat-data for the file safe-link is
+                                * for */
+       d64 size;               /* size to which file should be truncated */
+} safelink_t;
+
+/*
+ * locality where safe-link items are stored. Next to the objectid of root
+ * directory.
+ */
+static oid_t safe_link_locality(reiser4_tree * tree)
+{
+       return get_key_objectid(get_super_private(tree->super)->df_plug->
+                               root_dir_key(tree->super)) + 1;
+}
+
+/*
+  Construct a key for the safe-link. Key has the following format:
+
+|        60     | 4 |        64        | 4 |      60       |         64       |
++---------------+---+------------------+---+---------------+------------------+
+|   locality    | 0 |        0         | 0 |   objectid    |     link type    |
++---------------+---+------------------+---+---------------+------------------+
+|                   |                  |                   |                  |
+|     8 bytes       |     8 bytes      |      8 bytes      |      8 bytes     |
+
+   This is in large keys format. In small keys format second 8 byte chunk is
+   out. Locality is a constant returned by safe_link_locality(). objectid is
+   an oid of a file on which operation protected by this safe-link is
+   performed. link-type is used to distinguish safe-links for different
+   operations.
+
+ */
+static reiser4_key *build_link_key(reiser4_tree * tree, oid_t oid,
+                                  reiser4_safe_link_t link, reiser4_key * key)
+{
+       reiser4_key_init(key);
+       set_key_locality(key, safe_link_locality(tree));
+       set_key_objectid(key, oid);
+       set_key_offset(key, link);
+       return key;
+}
+
+/*
+ * how much disk space is necessary to insert and remove (in the
+ * error-handling path) safe-link.
+ */
+static __u64 safe_link_tograb(reiser4_tree * tree)
+{
+       return
+           /* insert safe link */
+           estimate_one_insert_item(tree) +
+           /* remove safe link */
+           estimate_one_item_removal(tree) +
+           /* drill to the leaf level during insertion */
+           1 + estimate_one_insert_item(tree) +
+           /*
+            * possible update of existing safe-link. Actually, if
+            * safe-link existed already (we failed to remove it), then no
+            * insertion is necessary, so this term is already "covered",
+            * but for simplicity let's left it.
+            */
+           1;
+}
+
+/*
+ * grab enough disk space to insert and remove (in the error-handling path)
+ * safe-link.
+ */
+int safe_link_grab(reiser4_tree * tree, reiser4_ba_flags_t flags)
+{
+       int result;
+
+       grab_space_enable();
+       /* The sbinfo->delete_mutex can be taken here.
+        * safe_link_release() should be called before leaving reiser4
+        * context. */
+       result =
+           reiser4_grab_reserved(tree->super, safe_link_tograb(tree), flags);
+       grab_space_enable();
+       return result;
+}
+
+/*
+ * release unused disk space reserved by safe_link_grab().
+ */
+void safe_link_release(reiser4_tree * tree)
+{
+       reiser4_release_reserved(tree->super);
+}
+
+/*
+ * insert into tree safe-link for operation @link on inode @inode.
+ */
+int safe_link_add(struct inode *inode, reiser4_safe_link_t link)
+{
+       reiser4_key key;
+       safelink_t sl;
+       int length;
+       int result;
+       reiser4_tree *tree;
+
+       build_sd_key(inode, &sl.sdkey);
+       length = sizeof sl.sdkey;
+
+       if (link == SAFE_TRUNCATE) {
+               /*
+                * for truncate we have to store final file length also,
+                * expand item.
+                */
+               length += sizeof(sl.size);
+               put_unaligned(cpu_to_le64(inode->i_size), &sl.size);
+       }
+       tree = reiser4_tree_by_inode(inode);
+       build_link_key(tree, get_inode_oid(inode), link, &key);
+
+       result = store_black_box(tree, &key, &sl, length);
+       if (result == -EEXIST)
+               result = update_black_box(tree, &key, &sl, length);
+       return result;
+}
+
+/*
+ * remove safe-link corresponding to the operation @link on inode @inode from
+ * the tree.
+ */
+int safe_link_del(reiser4_tree * tree, oid_t oid, reiser4_safe_link_t link)
+{
+       reiser4_key key;
+
+       return kill_black_box(tree, build_link_key(tree, oid, link, &key));
+}
+
+/*
+ * in-memory structure to keep information extracted from safe-link. This is
+ * used to iterate over all safe-links.
+ */
+typedef struct {
+       reiser4_tree *tree;     /* internal tree */
+       reiser4_key key;        /* safe-link key */
+       reiser4_key sdkey;      /* key of object stat-data */
+       reiser4_safe_link_t link;       /* safe-link type */
+       oid_t oid;              /* object oid */
+       __u64 size;             /* final size for truncate */
+} safe_link_context;
+
+/*
+ * start iterating over all safe-links.
+ */
+static void safe_link_iter_begin(reiser4_tree * tree, safe_link_context * ctx)
+{
+       ctx->tree = tree;
+       reiser4_key_init(&ctx->key);
+       set_key_locality(&ctx->key, safe_link_locality(tree));
+       set_key_objectid(&ctx->key, get_key_objectid(reiser4_max_key()));
+       set_key_offset(&ctx->key, get_key_offset(reiser4_max_key()));
+}
+
+/*
+ * return next safe-link.
+ */
+static int safe_link_iter_next(safe_link_context * ctx)
+{
+       int result;
+       safelink_t sl;
+
+       result = load_black_box(ctx->tree, &ctx->key, &sl, sizeof sl, 0);
+       if (result == 0) {
+               ctx->oid = get_key_objectid(&ctx->key);
+               ctx->link = get_key_offset(&ctx->key);
+               ctx->sdkey = sl.sdkey;
+               if (ctx->link == SAFE_TRUNCATE)
+                       ctx->size = le64_to_cpu(get_unaligned(&sl.size));
+       }
+       return result;
+}
+
+/*
+ * check are there any more safe-links left in the tree.
+ */
+static int safe_link_iter_finished(safe_link_context * ctx)
+{
+       return get_key_locality(&ctx->key) != safe_link_locality(ctx->tree);
+}
+
+/*
+ * finish safe-link iteration.
+ */
+static void safe_link_iter_end(safe_link_context * ctx)
+{
+       /* nothing special */
+}
+
+/*
+ * process single safe-link.
+ */
+static int process_safelink(struct super_block *super, reiser4_safe_link_t link,
+                           reiser4_key * sdkey, oid_t oid, __u64 size)
+{
+       struct inode *inode;
+       int result;
+
+       /*
+        * obtain object inode by reiser4_iget(), then call object plugin
+        * ->safelink() method to do actual work, then delete safe-link on
+        * success.
+        */
+       inode = reiser4_iget(super, sdkey, 1);
+       if (!IS_ERR(inode)) {
+               file_plugin *fplug;
+
+               fplug = inode_file_plugin(inode);
+               assert("nikita-3428", fplug != NULL);
+               assert("", oid == get_inode_oid(inode));
+               if (fplug->safelink != NULL) {
+                       /* reiser4_txn_restart_current is not necessary because
+                        * mounting is signle thread. However, without it
+                        * deadlock detection code will complain (see
+                        * nikita-3361). */
+                       reiser4_txn_restart_current();
+                       result = fplug->safelink(inode, link, size);
+               } else {
+                       warning("nikita-3430",
+                               "Cannot handle safelink for %lli",
+                               (unsigned long long)oid);
+                       reiser4_print_key("key", sdkey);
+                       result = 0;
+               }
+               if (result != 0) {
+                       warning("nikita-3431",
+                               "Error processing safelink for %lli: %i",
+                               (unsigned long long)oid, result);
+               }
+               reiser4_iget_complete(inode);
+               iput(inode);
+               if (result == 0) {
+                       result = safe_link_grab(reiser4_get_tree(super), BA_CAN_COMMIT);
+                       if (result == 0)
+                               result =
+                                   safe_link_del(reiser4_get_tree(super), oid, link);
+                       safe_link_release(reiser4_get_tree(super));
+                       /*
+                        * restart transaction: if there was large number of
+                        * safe-links, their processing may fail to fit into
+                        * single transaction.
+                        */
+                       if (result == 0)
+                               reiser4_txn_restart_current();
+               }
+       } else
+               result = PTR_ERR(inode);
+       return result;
+}
+
+/*
+ * iterate over all safe-links in the file-system processing them one by one.
+ */
+int process_safelinks(struct super_block *super)
+{
+       safe_link_context ctx;
+       int result;
+
+       if (rofs_super(super))
+               /* do nothing on the read-only file system */
+               return 0;
+       safe_link_iter_begin(&get_super_private(super)->tree, &ctx);
+       result = 0;
+       do {
+               result = safe_link_iter_next(&ctx);
+               if (safe_link_iter_finished(&ctx) || result == -ENOENT) {
+                       result = 0;
+                       break;
+               }
+               if (result == 0)
+                       result = process_safelink(super, ctx.link,
+                                                 &ctx.sdkey, ctx.oid,
+                                                 ctx.size);
+       } while (result == 0);
+       safe_link_iter_end(&ctx);
+       return result;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/safe_link.h linux-2.6.20/fs/reiser4/safe_link.h
--- linux-2.6.20.orig/fs/reiser4/safe_link.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/safe_link.h 2007-05-06 14:50:43.867028218 +0400
@@ -0,0 +1,29 @@
+/* Copyright 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Safe-links. See safe_link.c for details. */
+
+#if !defined( __FS_SAFE_LINK_H__ )
+#define __FS_SAFE_LINK_H__
+
+#include "tree.h"
+
+int safe_link_grab(reiser4_tree * tree, reiser4_ba_flags_t flags);
+void safe_link_release(reiser4_tree * tree);
+int safe_link_add(struct inode *inode, reiser4_safe_link_t link);
+int safe_link_del(reiser4_tree *, oid_t oid, reiser4_safe_link_t link);
+
+int process_safelinks(struct super_block *super);
+
+/* __FS_SAFE_LINK_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/seal.c linux-2.6.20/fs/reiser4/seal.c
--- linux-2.6.20.orig/fs/reiser4/seal.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/seal.c      2007-05-06 14:50:43.871029467 +0400
@@ -0,0 +1,218 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+/* Seals implementation. */
+/* Seals are "weak" tree pointers. They are analogous to tree coords in
+   allowing to bypass tree traversal. But normal usage of coords implies that
+   node pointed to by coord is locked, whereas seals don't keep a lock (or
+   even a reference) to znode. In stead, each znode contains a version number,
+   increased on each znode modification. This version number is copied into a
+   seal when seal is created. Later, one can "validate" seal by calling
+   reiser4_seal_validate(). If znode is in cache and its version number is
+   still the same, seal is "pristine" and coord associated with it can be
+   re-used immediately.
+
+   If, on the other hand, znode is out of cache, or it is obviously different
+   one from the znode seal was initially attached to (for example, it is on
+   the different level, or is being removed from the tree), seal is
+   irreparably invalid ("burned") and tree traversal has to be repeated.
+
+   Otherwise, there is some hope, that while znode was modified (and seal was
+   "broken" as a result), key attached to the seal is still in the node. This
+   is checked by first comparing this key with delimiting keys of node and, if
+   key is ok, doing intra-node lookup.
+
+   Znode version is maintained in the following way:
+
+   there is reiser4_tree.znode_epoch counter. Whenever new znode is created,
+   znode_epoch is incremented and its new value is stored in ->version field
+   of new znode. Whenever znode is dirtied (which means it was probably
+   modified), znode_epoch is also incremented and its new value is stored in
+   znode->version. This is done so, because just incrementing znode->version
+   on each update is not enough: it may so happen, that znode get deleted, new
+   znode is allocated for the same disk block and gets the same version
+   counter, tricking seal code into false positive.
+*/
+
+#include "forward.h"
+#include "debug.h"
+#include "key.h"
+#include "coord.h"
+#include "seal.h"
+#include "plugin/item/item.h"
+#include "plugin/node/node.h"
+#include "jnode.h"
+#include "znode.h"
+#include "super.h"
+
+static znode *seal_node(const seal_t * seal);
+static int seal_matches(const seal_t * seal, znode * node);
+
+/* initialise seal. This can be called several times on the same seal. @coord
+   and @key can be NULL.  */
+void reiser4_seal_init(seal_t * seal /* seal to initialise */ ,
+                      const coord_t * coord /* coord @seal will be
+                                             * attached to */ ,
+                      const reiser4_key * key UNUSED_ARG /* key @seal will be
+                                                          * attached to */ )
+{
+       assert("nikita-1886", seal != NULL);
+       memset(seal, 0, sizeof *seal);
+       if (coord != NULL) {
+               znode *node;
+
+               node = coord->node;
+               assert("nikita-1987", node != NULL);
+               spin_lock_znode(node);
+               seal->version = node->version;
+               assert("nikita-1988", seal->version != 0);
+               seal->block = *znode_get_block(node);
+#if REISER4_DEBUG
+               seal->coord1 = *coord;
+               if (key != NULL)
+                       seal->key = *key;
+#endif
+               spin_unlock_znode(node);
+       }
+}
+
+/* finish with seal */
+void reiser4_seal_done(seal_t * seal /* seal to clear */ )
+{
+       assert("nikita-1887", seal != NULL);
+       seal->version = 0;
+}
+
+/* true if seal was initialised */
+int reiser4_seal_is_set(const seal_t * seal /* seal to query */ )
+{
+       assert("nikita-1890", seal != NULL);
+       return seal->version != 0;
+}
+
+#if REISER4_DEBUG
+/* helper function for reiser4_seal_validate(). It checks that item at @coord
+ * has expected key. This is to detect cases where node was modified but wasn't
+ * marked dirty. */
+static inline int check_seal_match(const coord_t * coord /* coord to check */ ,
+                                  const reiser4_key * k /* expected key */ )
+{
+       reiser4_key ukey;
+
+       return (coord->between != AT_UNIT) ||
+           /* FIXME-VS: we only can compare keys for items whose units
+              represent exactly one key */
+           ((coord_is_existing_unit(coord))
+            && (item_is_extent(coord)
+                || keyeq(k, unit_key_by_coord(coord, &ukey))))
+           || ((coord_is_existing_unit(coord)) && (item_is_ctail(coord))
+               && keyge(k, unit_key_by_coord(coord, &ukey)));
+}
+#endif
+
+/* this is used by reiser4_seal_validate. It accepts return value of
+ * longterm_lock_znode and returns 1 if it can be interpreted as seal
+ * validation failure. For instance, when longterm_lock_znode returns -EINVAL,
+ * reiser4_seal_validate returns -E_REPEAT and caller will call tre search.
+ * We cannot do this in longterm_lock_znode(), because sometimes we want to
+ * distinguish between -EINVAL and -E_REPEAT. */
+static int should_repeat(int return_code)
+{
+       return return_code == -EINVAL;
+}
+
+/* (re-)validate seal.
+
+   Checks whether seal is pristine, and try to revalidate it if possible.
+
+   If seal was burned, or broken irreparably, return -E_REPEAT.
+
+   NOTE-NIKITA currently reiser4_seal_validate() returns -E_REPEAT if key we are
+   looking for is in range of keys covered by the sealed node, but item wasn't
+   found by node ->lookup() method. Alternative is to return -ENOENT in this
+   case, but this would complicate callers logic.
+
+*/
+int reiser4_seal_validate(seal_t * seal /* seal to validate */,
+                         coord_t * coord /* coord to validate against */,
+                         const reiser4_key * key /* key to validate against */,
+                         lock_handle * lh /* resulting lock handle */,
+                         znode_lock_mode mode /* lock node */,
+                         znode_lock_request request /* locking priority */)
+{
+       znode *node;
+       int result;
+
+       assert("nikita-1889", seal != NULL);
+       assert("nikita-1881", reiser4_seal_is_set(seal));
+       assert("nikita-1882", key != NULL);
+       assert("nikita-1883", coord != NULL);
+       assert("nikita-1884", lh != NULL);
+       assert("nikita-1885", keyeq(&seal->key, key));
+       assert("nikita-1989", coords_equal(&seal->coord1, coord));
+
+       /* obtain znode by block number */
+       node = seal_node(seal);
+       if (node != NULL) {
+               /* znode was in cache, lock it */
+               result = longterm_lock_znode(lh, node, mode, request);
+               zput(node);
+               if (result == 0) {
+                       if (seal_matches(seal, node)) {
+                               /* if seal version and znode version
+                                  coincide */
+                               ON_DEBUG(coord_update_v(coord));
+                               assert("nikita-1990",
+                                      node == seal->coord1.node);
+                               assert("nikita-1898",
+                                      WITH_DATA_RET(coord->node, 1,
+                                                    check_seal_match(coord,
+                                                                     key)));
+                       } else
+                               result = RETERR(-E_REPEAT);
+               }
+               if (result != 0) {
+                       if (should_repeat(result))
+                               result = RETERR(-E_REPEAT);
+                       /* unlock node on failure */
+                       done_lh(lh);
+               }
+       } else {
+               /* znode wasn't in cache */
+               result = RETERR(-E_REPEAT);
+       }
+       return result;
+}
+
+/* helpers functions */
+
+/* obtain reference to znode seal points to, if in cache */
+static znode *seal_node(const seal_t * seal /* seal to query */ )
+{
+       assert("nikita-1891", seal != NULL);
+       return zlook(current_tree, &seal->block);
+}
+
+/* true if @seal version and @node version coincide */
+static int seal_matches(const seal_t * seal /* seal to check */ ,
+                       znode * node /* node to check */ )
+{
+       int result;
+
+       assert("nikita-1991", seal != NULL);
+       assert("nikita-1993", node != NULL);
+
+       spin_lock_znode(node);
+       result = (seal->version == node->version);
+       spin_unlock_znode(node);
+       return result;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/seal.h linux-2.6.20/fs/reiser4/seal.h
--- linux-2.6.20.orig/fs/reiser4/seal.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/seal.h      2007-05-06 14:50:43.871029467 +0400
@@ -0,0 +1,49 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Declaration of seals: "weak" tree pointers. See seal.c for comments. */
+
+#ifndef __SEAL_H__
+#define __SEAL_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+
+/* for __u?? types */
+/*#include <linux/types.h>*/
+
+/* seal. See comment at the top of seal.c */
+typedef struct seal_s {
+       /* version of znode recorder at the time of seal creation */
+       __u64 version;
+       /* block number of znode attached to this seal */
+       reiser4_block_nr block;
+#if REISER4_DEBUG
+       /* coord this seal is attached to. For debugging. */
+       coord_t coord1;
+       /* key this seal is attached to. For debugging. */
+       reiser4_key key;
+#endif
+} seal_t;
+
+extern void reiser4_seal_init(seal_t *, const coord_t *, const reiser4_key *);
+extern void reiser4_seal_done(seal_t *);
+extern int reiser4_seal_is_set(const seal_t *);
+extern int reiser4_seal_validate(seal_t *, coord_t *,
+                        const reiser4_key *, lock_handle *,
+                        znode_lock_mode mode, znode_lock_request request);
+
+/* __SEAL_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/search.c linux-2.6.20/fs/reiser4/search.c
--- linux-2.6.20.orig/fs/reiser4/search.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/search.c    2007-05-06 14:50:43.871029467 +0400
@@ -0,0 +1,1611 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "seal.h"
+#include "plugin/item/item.h"
+#include "plugin/node/node.h"
+#include "plugin/plugin.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "tree.h"
+#include "reiser4.h"
+#include "super.h"
+#include "inode.h"
+
+#include <linux/slab.h>
+
+static const char *bias_name(lookup_bias bias);
+
+/* tree searching algorithm, intranode searching algorithms are in
+   plugin/node/ */
+
+/* tree lookup cache
+ *
+ * The coord by key cache consists of small list of recently accessed nodes
+ * maintained according to the LRU discipline. Before doing real top-to-down
+ * tree traversal this cache is scanned for nodes that can contain key
+ * requested.
+ *
+ * The efficiency of coord cache depends heavily on locality of reference for
+ * tree accesses. Our user level simulations show reasonably good hit ratios
+ * for coord cache under most loads so far.
+ */
+
+/* Initialise coord cache slot */
+static void cbk_cache_init_slot(cbk_cache_slot *slot)
+{
+       assert("nikita-345", slot != NULL);
+
+       INIT_LIST_HEAD(&slot->lru);
+       slot->node = NULL;
+}
+
+/* Initialize coord cache */
+int cbk_cache_init(cbk_cache *cache /* cache to init */ )
+{
+       int i;
+
+       assert("nikita-346", cache != NULL);
+
+       cache->slot =
+               kmalloc(sizeof(cbk_cache_slot) * cache->nr_slots,
+                       reiser4_ctx_gfp_mask_get());
+       if (cache->slot == NULL)
+               return RETERR(-ENOMEM);
+
+       INIT_LIST_HEAD(&cache->lru);
+       for (i = 0; i < cache->nr_slots; ++i) {
+               cbk_cache_init_slot(cache->slot + i);
+               list_add_tail(&((cache->slot + i)->lru), &cache->lru);
+       }
+       rwlock_init(&cache->guard);
+       return 0;
+}
+
+/* free cbk cache data */
+void cbk_cache_done(cbk_cache * cache /* cache to release */ )
+{
+       assert("nikita-2493", cache != NULL);
+       if (cache->slot != NULL) {
+               kfree(cache->slot);
+               cache->slot = NULL;
+       }
+}
+
+/* macro to iterate over all cbk cache slots */
+#define for_all_slots(cache, slot)                                             \
+       for ((slot) = list_entry((cache)->lru.next, cbk_cache_slot, lru);       \
+            &(cache)->lru != &(slot)->lru;                                     \
+            (slot) = list_entry(slot->lru.next, cbk_cache_slot, lru))
+
+#if REISER4_DEBUG
+/* this function assures that [cbk-cache-invariant] invariant holds */
+static int cbk_cache_invariant(const cbk_cache *cache)
+{
+       cbk_cache_slot *slot;
+       int result;
+       int unused;
+
+       if (cache->nr_slots == 0)
+               return 1;
+
+       assert("nikita-2469", cache != NULL);
+       unused = 0;
+       result = 1;
+       read_lock(&((cbk_cache *)cache)->guard);
+       for_all_slots(cache, slot) {
+               /* in LRU first go all `used' slots followed by `unused' */
+               if (unused && (slot->node != NULL))
+                       result = 0;
+               if (slot->node == NULL)
+                       unused = 1;
+               else {
+                       cbk_cache_slot *scan;
+
+                       /* all cached nodes are different */
+                       scan = slot;
+                       while (result) {
+                               scan = list_entry(scan->lru.next, cbk_cache_slot, lru);
+                               if (&cache->lru == &scan->lru)
+                                       break;
+                               if (slot->node == scan->node)
+                                       result = 0;
+                       }
+               }
+               if (!result)
+                       break;
+       }
+       read_unlock(&((cbk_cache *)cache)->guard);
+       return result;
+}
+
+#endif
+
+/* Remove references, if any, to @node from coord cache */
+void cbk_cache_invalidate(const znode * node /* node to remove from cache */ ,
+                         reiser4_tree * tree /* tree to remove node from */ )
+{
+       cbk_cache_slot *slot;
+       cbk_cache *cache;
+       int i;
+
+       assert("nikita-350", node != NULL);
+       assert("nikita-1479", LOCK_CNT_GTZ(rw_locked_tree));
+
+       cache = &tree->cbk_cache;
+       assert("nikita-2470", cbk_cache_invariant(cache));
+
+       write_lock(&(cache->guard));
+       for (i = 0, slot = cache->slot; i < cache->nr_slots; ++i, ++slot) {
+               if (slot->node == node) {
+                       list_move_tail(&slot->lru, &cache->lru);
+                       slot->node = NULL;
+                       break;
+               }
+       }
+       write_unlock(&(cache->guard));
+       assert("nikita-2471", cbk_cache_invariant(cache));
+}
+
+/* add to the cbk-cache in the "tree" information about "node". This
+    can actually be update of existing slot in a cache. */
+static void cbk_cache_add(const znode *node /* node to add to the cache */ )
+{
+       cbk_cache *cache;
+       cbk_cache_slot *slot;
+       int i;
+
+       assert("nikita-352", node != NULL);
+
+       cache = &znode_get_tree(node)->cbk_cache;
+       assert("nikita-2472", cbk_cache_invariant(cache));
+
+       if (cache->nr_slots == 0)
+               return;
+
+       write_lock(&(cache->guard));
+       /* find slot to update/add */
+       for (i = 0, slot = cache->slot; i < cache->nr_slots; ++i, ++slot) {
+               /* oops, this node is already in a cache */
+               if (slot->node == node)
+                       break;
+       }
+       /* if all slots are used, reuse least recently used one */
+       if (i == cache->nr_slots) {
+               slot = list_entry(cache->lru.prev, cbk_cache_slot, lru);
+               slot->node = (znode *) node;
+       }
+       list_move(&slot->lru, &cache->lru);
+       write_unlock(&(cache->guard));
+       assert("nikita-2473", cbk_cache_invariant(cache));
+}
+
+static int setup_delimiting_keys(cbk_handle * h);
+static lookup_result coord_by_handle(cbk_handle * handle);
+static lookup_result traverse_tree(cbk_handle * h);
+static int cbk_cache_search(cbk_handle * h);
+
+static level_lookup_result cbk_level_lookup(cbk_handle * h);
+static level_lookup_result cbk_node_lookup(cbk_handle * h);
+
+/* helper functions */
+
+static void update_stale_dk(reiser4_tree * tree, znode * node);
+
+/* release parent node during traversal */
+static void put_parent(cbk_handle * h);
+/* check consistency of fields */
+static int sanity_check(cbk_handle * h);
+/* release resources in handle */
+static void hput(cbk_handle * h);
+
+static level_lookup_result search_to_left(cbk_handle * h);
+
+/* pack numerous (numberous I should say) arguments of coord_by_key() into
+ * cbk_handle */
+static cbk_handle *cbk_pack(cbk_handle * handle,
+                           reiser4_tree * tree,
+                           const reiser4_key * key,
+                           coord_t * coord,
+                           lock_handle * active_lh,
+                           lock_handle * parent_lh,
+                           znode_lock_mode lock_mode,
+                           lookup_bias bias,
+                           tree_level lock_level,
+                           tree_level stop_level,
+                           __u32 flags, ra_info_t * info)
+{
+       memset(handle, 0, sizeof *handle);
+
+       handle->tree = tree;
+       handle->key = key;
+       handle->lock_mode = lock_mode;
+       handle->bias = bias;
+       handle->lock_level = lock_level;
+       handle->stop_level = stop_level;
+       handle->coord = coord;
+       /* set flags. See comment in tree.h:cbk_flags */
+       handle->flags = flags | CBK_TRUST_DK | CBK_USE_CRABLOCK;
+
+       handle->active_lh = active_lh;
+       handle->parent_lh = parent_lh;
+       handle->ra_info = info;
+       return handle;
+}
+
+/* main tree lookup procedure
+
+   Check coord cache. If key we are looking for is not found there, call cbk()
+   to do real tree traversal.
+
+   As we have extents on the twig level, @lock_level and @stop_level can
+   be different from LEAF_LEVEL and each other.
+
+   Thread cannot keep any reiser4 locks (tree, znode, dk spin-locks, or znode
+   long term locks) while calling this.
+*/
+lookup_result coord_by_key(reiser4_tree * tree /* tree to perform search
+                                                * in. Usually this tree is
+                                                * part of file-system
+                                                * super-block */ ,
+                          const reiser4_key * key /* key to look for */ ,
+                          coord_t * coord      /* where to store found
+                                                * position in a tree. Fields
+                                                * in "coord" are only valid if
+                                                * coord_by_key() returned
+                                                * "CBK_COORD_FOUND" */ ,
+                          lock_handle * lh,    /* resulting lock handle */
+                          znode_lock_mode lock_mode    /* type of lookup we
+                                                        * want on node. Pass
+                                                        * ZNODE_READ_LOCK here
+                                                        * if you only want to
+                                                        * read item found and
+                                                        * ZNODE_WRITE_LOCK if
+                                                        * you want to modify
+                                                        * it */ ,
+                          lookup_bias bias     /* what to return if coord
+                                                * with exactly the @key is
+                                                * not in the tree */ ,
+                          tree_level lock_level        /* tree level where to start
+                                                        * taking @lock type of
+                                                        * locks */ ,
+                          tree_level stop_level        /* tree level to stop. Pass
+                                                        * LEAF_LEVEL or TWIG_LEVEL
+                                                        * here Item being looked
+                                                        * for has to be between
+                                                        * @lock_level and
+                                                        * @stop_level, inclusive */ ,
+                          __u32 flags /* search flags */ ,
+                          ra_info_t *
+                          info
+                          /* information about desired tree traversal readahead */
+                          )
+{
+       cbk_handle handle;
+       lock_handle parent_lh;
+       lookup_result result;
+
+       init_lh(lh);
+       init_lh(&parent_lh);
+
+       assert("nikita-3023", reiser4_schedulable());
+
+       assert("nikita-353", tree != NULL);
+       assert("nikita-354", key != NULL);
+       assert("nikita-355", coord != NULL);
+       assert("nikita-356", (bias == FIND_EXACT)
+              || (bias == FIND_MAX_NOT_MORE_THAN));
+       assert("nikita-357", stop_level >= LEAF_LEVEL);
+       /* no locks can be held during tree traversal */
+       assert("nikita-2104", lock_stack_isclean(get_current_lock_stack()));
+
+       cbk_pack(&handle,
+                tree,
+                key,
+                coord,
+                lh,
+                &parent_lh,
+                lock_mode, bias, lock_level, stop_level, flags, info);
+
+       result = coord_by_handle(&handle);
+       assert("nikita-3247",
+              ergo(!IS_CBKERR(result), coord->node == lh->node));
+       return result;
+}
+
+/* like coord_by_key(), but starts traversal from vroot of @object rather than
+ * from tree root. */
+lookup_result reiser4_object_lookup(struct inode * object,
+                                   const reiser4_key * key,
+                                   coord_t * coord,
+                                   lock_handle * lh,
+                                   znode_lock_mode lock_mode,
+                                   lookup_bias bias,
+                                   tree_level lock_level,
+                                   tree_level stop_level, __u32 flags,
+                                   ra_info_t * info)
+{
+       cbk_handle handle;
+       lock_handle parent_lh;
+       lookup_result result;
+
+       init_lh(lh);
+       init_lh(&parent_lh);
+
+       assert("nikita-3023", reiser4_schedulable());
+
+       assert("nikita-354", key != NULL);
+       assert("nikita-355", coord != NULL);
+       assert("nikita-356", (bias == FIND_EXACT)
+              || (bias == FIND_MAX_NOT_MORE_THAN));
+       assert("nikita-357", stop_level >= LEAF_LEVEL);
+       /* no locks can be held during tree search by key */
+       assert("nikita-2104", lock_stack_isclean(get_current_lock_stack()));
+
+       cbk_pack(&handle,
+                object != NULL ? reiser4_tree_by_inode(object) : current_tree,
+                key,
+                coord,
+                lh,
+                &parent_lh,
+                lock_mode, bias, lock_level, stop_level, flags, info);
+       handle.object = object;
+
+       result = coord_by_handle(&handle);
+       assert("nikita-3247",
+              ergo(!IS_CBKERR(result), coord->node == lh->node));
+       return result;
+}
+
+/* lookup by cbk_handle. Common part of coord_by_key() and
+   reiser4_object_lookup(). */
+static lookup_result coord_by_handle(cbk_handle * handle)
+{
+       /*
+        * first check cbk_cache (which is look-aside cache for our tree) and
+        * of this fails, start traversal.
+        */
+       /* first check whether "key" is in cache of recent lookups. */
+       if (cbk_cache_search(handle) == 0)
+               return handle->result;
+       else
+               return traverse_tree(handle);
+}
+
+/* Execute actor for each item (or unit, depending on @through_units_p),
+   starting from @coord, right-ward, until either:
+
+   - end of the tree is reached
+   - unformatted node is met
+   - error occurred
+   - @actor returns 0 or less
+
+   Error code, or last actor return value is returned.
+
+   This is used by plugin/dir/hashe_dir.c:reiser4_find_entry() to move through
+   sequence of entries with identical keys and alikes.
+*/
+int reiser4_iterate_tree(reiser4_tree * tree /* tree to scan */ ,
+                        coord_t * coord /* coord to start from */ ,
+                        lock_handle * lh /* lock handle to start with and to
+                                          * update along the way */ ,
+                        tree_iterate_actor_t actor /* function to call on each
+                                                    * item/unit */ ,
+                        void *arg /* argument to pass to @actor */ ,
+                        znode_lock_mode mode /* lock mode on scanned nodes */ ,
+                        int through_units_p /* call @actor on each item or on
+                                             * each unit */ )
+{
+       int result;
+
+       assert("nikita-1143", tree != NULL);
+       assert("nikita-1145", coord != NULL);
+       assert("nikita-1146", lh != NULL);
+       assert("nikita-1147", actor != NULL);
+
+       result = zload(coord->node);
+       coord_clear_iplug(coord);
+       if (result != 0)
+               return result;
+       if (!coord_is_existing_unit(coord)) {
+               zrelse(coord->node);
+               return -ENOENT;
+       }
+       while ((result = actor(tree, coord, lh, arg)) > 0) {
+               /* move further  */
+               if ((through_units_p && coord_next_unit(coord)) ||
+                   (!through_units_p && coord_next_item(coord))) {
+                       do {
+                               lock_handle couple;
+
+                               /* move to the next node  */
+                               init_lh(&couple);
+                               result =
+                                   reiser4_get_right_neighbor(&couple,
+                                                              coord->node,
+                                                              (int)mode,
+                                                              GN_CAN_USE_UPPER_LEVELS);
+                               zrelse(coord->node);
+                               if (result == 0) {
+
+                                       result = zload(couple.node);
+                                       if (result != 0) {
+                                               done_lh(&couple);
+                                               return result;
+                                       }
+
+                                       coord_init_first_unit(coord,
+                                                             couple.node);
+                                       done_lh(lh);
+                                       move_lh(lh, &couple);
+                               } else
+                                       return result;
+                       } while (node_is_empty(coord->node));
+               }
+
+               assert("nikita-1149", coord_is_existing_unit(coord));
+       }
+       zrelse(coord->node);
+       return result;
+}
+
+/* return locked uber znode for @tree */
+int get_uber_znode(reiser4_tree * tree, znode_lock_mode mode,
+                  znode_lock_request pri, lock_handle * lh)
+{
+       int result;
+
+       result = longterm_lock_znode(lh, tree->uber, mode, pri);
+       return result;
+}
+
+/* true if @key is strictly within @node
+
+   we are looking for possibly non-unique key and it is item is at the edge of
+   @node. May be it is in the neighbor.
+*/
+static int znode_contains_key_strict(znode * node      /* node to check key
+                                                        * against */ ,
+                                    const reiser4_key *
+                                    key /* key to check */ ,
+                                    int isunique)
+{
+       int answer;
+
+       assert("nikita-1760", node != NULL);
+       assert("nikita-1722", key != NULL);
+
+       if (keyge(key, &node->rd_key))
+               return 0;
+
+       answer = keycmp(&node->ld_key, key);
+
+       if (isunique)
+               return answer != GREATER_THAN;
+       else
+               return answer == LESS_THAN;
+}
+
+/*
+ * Virtual Root (vroot) code.
+ *
+ *     For given file system object (e.g., regular file or directory) let's
+ *     define its "virtual root" as lowest in the tree (that is, furtherest
+ *     from the tree root) node such that all body items of said object are
+ *     located in a tree rooted at this node.
+ *
+ *     Once vroot of object is found all tree lookups for items within body of
+ *     this object ("object lookups") can be started from its vroot rather
+ *     than from real root. This has following advantages:
+ *
+ *         1. amount of nodes traversed during lookup (and, hence, amount of
+ *         key comparisons made) decreases, and
+ *
+ *         2. contention on tree root is decreased. This latter was actually
+ *         motivating reason behind vroot, because spin lock of root node,
+ *         which is taken when acquiring long-term lock on root node is the
+ *         hottest lock in the reiser4.
+ *
+ * How to find vroot.
+ *
+ *     When vroot of object F is not yet determined, all object lookups start
+ *     from the root of the tree. At each tree level during traversal we have
+ *     a node N such that a key we are looking for (which is the key inside
+ *     object's body) is located within N. In function handle_vroot() called
+ *     from cbk_level_lookup() we check whether N is possible vroot for
+ *     F. Check is trivial---if neither leftmost nor rightmost item of N
+ *     belongs to F (and we already have helpful ->owns_item() method of
+ *     object plugin for this), then N is possible vroot of F. This, of
+ *     course, relies on the assumption that each object occupies contiguous
+ *     range of keys in the tree.
+ *
+ *     Thus, traversing tree downward and checking each node as we go, we can
+ *     find lowest such node, which, by definition, is vroot.
+ *
+ * How to track vroot.
+ *
+ *     Nohow. If actual vroot changes, next object lookup will just restart
+ *     from the actual tree root, refreshing object's vroot along the way.
+ *
+ */
+
+/*
+ * Check whether @node is possible vroot of @object.
+ */
+static void handle_vroot(struct inode *object, znode * node)
+{
+       file_plugin *fplug;
+       coord_t coord;
+
+       fplug = inode_file_plugin(object);
+       assert("nikita-3353", fplug != NULL);
+       assert("nikita-3354", fplug->owns_item != NULL);
+
+       if (unlikely(node_is_empty(node)))
+               return;
+
+       coord_init_first_unit(&coord, node);
+       /*
+        * if leftmost item of @node belongs to @object, we cannot be sure
+        * that @node is vroot of @object, because, some items of @object are
+        * probably in the sub-tree rooted at the left neighbor of @node.
+        */
+       if (fplug->owns_item(object, &coord))
+               return;
+       coord_init_last_unit(&coord, node);
+       /* mutatis mutandis for the rightmost item */
+       if (fplug->owns_item(object, &coord))
+               return;
+       /* otherwise, @node is possible vroot of @object */
+       inode_set_vroot(object, node);
+}
+
+/*
+ * helper function used by traverse tree to start tree traversal not from the
+ * tree root, but from @h->object's vroot, if possible.
+ */
+static int prepare_object_lookup(cbk_handle * h)
+{
+       znode *vroot;
+       int result;
+
+       vroot = inode_get_vroot(h->object);
+       if (vroot == NULL) {
+               /*
+                * object doesn't have known vroot, start from real tree root.
+                */
+               return LOOKUP_CONT;
+       }
+
+       h->level = znode_get_level(vroot);
+       /* take a long-term lock on vroot */
+       h->result = longterm_lock_znode(h->active_lh, vroot,
+                                       cbk_lock_mode(h->level, h),
+                                       ZNODE_LOCK_LOPRI);
+       result = LOOKUP_REST;
+       if (h->result == 0) {
+               int isunique;
+               int inside;
+
+               isunique = h->flags & CBK_UNIQUE;
+               /* check that key is inside vroot */
+               read_lock_dk(h->tree);
+               inside = (znode_contains_key_strict(vroot, h->key, isunique) &&
+                         !ZF_ISSET(vroot, JNODE_HEARD_BANSHEE));
+               read_unlock_dk(h->tree);
+               if (inside) {
+                       h->result = zload(vroot);
+                       if (h->result == 0) {
+                               /* search for key in vroot. */
+                               result = cbk_node_lookup(h);
+                               zrelse(vroot);  /*h->active_lh->node); */
+                               if (h->active_lh->node != vroot) {
+                                       result = LOOKUP_REST;
+                               } else if (result == LOOKUP_CONT) {
+                                       move_lh(h->parent_lh, h->active_lh);
+                                       h->flags &= ~CBK_DKSET;
+                               }
+                       }
+               }
+       }
+
+       zput(vroot);
+
+       if (IS_CBKERR(h->result) || result == LOOKUP_REST)
+               hput(h);
+       return result;
+}
+
+/* main function that handles common parts of tree traversal: starting
+    (fake znode handling), restarts, error handling, completion */
+static lookup_result traverse_tree(cbk_handle * h /* search handle */ )
+{
+       int done;
+       int iterations;
+       int vroot_used;
+
+       assert("nikita-365", h != NULL);
+       assert("nikita-366", h->tree != NULL);
+       assert("nikita-367", h->key != NULL);
+       assert("nikita-368", h->coord != NULL);
+       assert("nikita-369", (h->bias == FIND_EXACT)
+              || (h->bias == FIND_MAX_NOT_MORE_THAN));
+       assert("nikita-370", h->stop_level >= LEAF_LEVEL);
+       assert("nikita-2949", !(h->flags & CBK_DKSET));
+       assert("zam-355", lock_stack_isclean(get_current_lock_stack()));
+
+       done = 0;
+       iterations = 0;
+       vroot_used = 0;
+
+       /* loop for restarts */
+      restart:
+
+       assert("nikita-3024", reiser4_schedulable());
+
+       h->result = CBK_COORD_FOUND;
+       /* connect_znode() needs it */
+       h->ld_key = *reiser4_min_key();
+       h->rd_key = *reiser4_max_key();
+       h->flags |= CBK_DKSET;
+       h->error = NULL;
+
+       if (!vroot_used && h->object != NULL) {
+               vroot_used = 1;
+               done = prepare_object_lookup(h);
+               if (done == LOOKUP_REST) {
+                       goto restart;
+               } else if (done == LOOKUP_DONE)
+                       return h->result;
+       }
+       if (h->parent_lh->node == NULL) {
+               done =
+                   get_uber_znode(h->tree, ZNODE_READ_LOCK, ZNODE_LOCK_LOPRI,
+                                  h->parent_lh);
+
+               assert("nikita-1637", done != -E_DEADLOCK);
+
+               h->block = h->tree->root_block;
+               h->level = h->tree->height;
+               h->coord->node = h->parent_lh->node;
+
+               if (done != 0)
+                       return done;
+       }
+
+       /* loop descending a tree */
+       while (!done) {
+
+               if (unlikely((iterations > REISER4_CBK_ITERATIONS_LIMIT) &&
+                            IS_POW(iterations))) {
+                       warning("nikita-1481", "Too many iterations: %i",
+                               iterations);
+                       reiser4_print_key("key", h->key);
+                       ++iterations;
+               } else if (unlikely(iterations > REISER4_MAX_CBK_ITERATIONS)) {
+                       h->error =
+                           "reiser-2018: Too many iterations. Tree corrupted, or (less likely) starvation occurring.";
+                       h->result = RETERR(-EIO);
+                       break;
+               }
+               switch (cbk_level_lookup(h)) {
+               case LOOKUP_CONT:
+                       move_lh(h->parent_lh, h->active_lh);
+                       continue;
+               default:
+                       wrong_return_value("nikita-372", "cbk_level");
+               case LOOKUP_DONE:
+                       done = 1;
+                       break;
+               case LOOKUP_REST:
+                       hput(h);
+                       /* deadlock avoidance is normal case. */
+                       if (h->result != -E_DEADLOCK)
+                               ++iterations;
+                       reiser4_preempt_point();
+                       goto restart;
+               }
+       }
+       /* that's all. The rest is error handling */
+       if (unlikely(h->error != NULL)) {
+               warning("nikita-373", "%s: level: %i, "
+                       "lock_level: %i, stop_level: %i "
+                       "lock_mode: %s, bias: %s",
+                       h->error, h->level, h->lock_level, h->stop_level,
+                       lock_mode_name(h->lock_mode), bias_name(h->bias));
+               reiser4_print_address("block", &h->block);
+               reiser4_print_key("key", h->key);
+               print_coord_content("coord", h->coord);
+       }
+       /* `unlikely' error case */
+       if (unlikely(IS_CBKERR(h->result))) {
+               /* failure. do cleanup */
+               hput(h);
+       } else {
+               assert("nikita-1605", WITH_DATA_RET
+                      (h->coord->node, 1,
+                       ergo((h->result == CBK_COORD_FOUND) &&
+                            (h->bias == FIND_EXACT) &&
+                            (!node_is_empty(h->coord->node)),
+                            coord_is_existing_item(h->coord))));
+       }
+       return h->result;
+}
+
+/* find delimiting keys of child
+
+   Determine left and right delimiting keys for child pointed to by
+   @parent_coord.
+
+*/
+static void find_child_delimiting_keys(znode * parent  /* parent znode, passed
+                                                        * locked */ ,
+                                      const coord_t * parent_coord     /* coord where
+                                                                        * pointer to
+                                                                        * child is
+                                                                        * stored */ ,
+                                      reiser4_key * ld /* where to store left
+                                                        * delimiting key */ ,
+                                      reiser4_key * rd /* where to store right
+                                                        * delimiting key */ )
+{
+       coord_t neighbor;
+
+       assert("nikita-1484", parent != NULL);
+       assert_rw_locked(&(znode_get_tree(parent)->dk_lock));
+
+       coord_dup(&neighbor, parent_coord);
+
+       if (neighbor.between == AT_UNIT)
+               /* imitate item ->lookup() behavior. */
+               neighbor.between = AFTER_UNIT;
+
+       if (coord_set_to_left(&neighbor) == 0)
+               unit_key_by_coord(&neighbor, ld);
+       else {
+               assert("nikita-14851", 0);
+               *ld = *znode_get_ld_key(parent);
+       }
+
+       coord_dup(&neighbor, parent_coord);
+       if (neighbor.between == AT_UNIT)
+               neighbor.between = AFTER_UNIT;
+       if (coord_set_to_right(&neighbor) == 0)
+               unit_key_by_coord(&neighbor, rd);
+       else
+               *rd = *znode_get_rd_key(parent);
+}
+
+/*
+ * setup delimiting keys for a child
+ *
+ * @parent parent node
+ *
+ * @coord location in @parent where pointer to @child is
+ *
+ * @child child node
+ */
+int
+set_child_delimiting_keys(znode * parent, const coord_t * coord, znode * child)
+{
+       reiser4_tree *tree;
+
+       assert("nikita-2952",
+              znode_get_level(parent) == znode_get_level(coord->node));
+
+       /* fast check without taking dk lock. This is safe, because
+        * JNODE_DKSET is never cleared once set. */
+       if (!ZF_ISSET(child, JNODE_DKSET)) {
+               tree = znode_get_tree(parent);
+               write_lock_dk(tree);
+               if (likely(!ZF_ISSET(child, JNODE_DKSET))) {
+                       find_child_delimiting_keys(parent, coord,
+                                                  &child->ld_key,
+                                                  &child->rd_key);
+                       ON_DEBUG(child->ld_key_version =
+                                atomic_inc_return(&delim_key_version);
+                                child->rd_key_version =
+                                atomic_inc_return(&delim_key_version););
+                       ZF_SET(child, JNODE_DKSET);
+               }
+               write_unlock_dk(tree);
+               return 1;
+       }
+       return 0;
+}
+
+/* Perform tree lookup at one level. This is called from cbk_traverse()
+   function that drives lookup through tree and calls cbk_node_lookup() to
+   perform lookup within one node.
+
+   See comments in a code.
+*/
+static level_lookup_result cbk_level_lookup(cbk_handle * h /* search handle */ )
+{
+       int ret;
+       int setdk;
+       int ldkeyset = 0;
+       reiser4_key ldkey;
+       reiser4_key key;
+       znode *active;
+
+       assert("nikita-3025", reiser4_schedulable());
+
+       /* acquire reference to @active node */
+       active =
+           zget(h->tree, &h->block, h->parent_lh->node, h->level,
+                reiser4_ctx_gfp_mask_get());
+
+       if (IS_ERR(active)) {
+               h->result = PTR_ERR(active);
+               return LOOKUP_DONE;
+       }
+
+       /* lock @active */
+       h->result = longterm_lock_znode(h->active_lh,
+                                       active,
+                                       cbk_lock_mode(h->level, h),
+                                       ZNODE_LOCK_LOPRI);
+       /* longterm_lock_znode() acquires additional reference to znode (which
+          will be later released by longterm_unlock_znode()). Release
+          reference acquired by zget().
+        */
+       zput(active);
+       if (unlikely(h->result != 0))
+               goto fail_or_restart;
+
+       setdk = 0;
+       /* if @active is accessed for the first time, setup delimiting keys on
+          it. Delimiting keys are taken from the parent node. See
+          setup_delimiting_keys() for details.
+        */
+       if (h->flags & CBK_DKSET) {
+               setdk = setup_delimiting_keys(h);
+               h->flags &= ~CBK_DKSET;
+       } else {
+               znode *parent;
+
+               parent = h->parent_lh->node;
+               h->result = zload(parent);
+               if (unlikely(h->result != 0))
+                       goto fail_or_restart;
+
+               if (!ZF_ISSET(active, JNODE_DKSET))
+                       setdk = set_child_delimiting_keys(parent,
+                                                         h->coord, active);
+               else {
+                       read_lock_dk(h->tree);
+                       find_child_delimiting_keys(parent, h->coord, &ldkey,
+                                                  &key);
+                       read_unlock_dk(h->tree);
+                       ldkeyset = 1;
+               }
+               zrelse(parent);
+       }
+
+       /* this is ugly kludge. Reminder: this is necessary, because
+          ->lookup() method returns coord with ->between field probably set
+          to something different from AT_UNIT.
+        */
+       h->coord->between = AT_UNIT;
+
+       if (znode_just_created(active) && (h->coord->node != NULL)) {
+               write_lock_tree(h->tree);
+               /* if we are going to load znode right now, setup
+                  ->in_parent: coord where pointer to this node is stored in
+                  parent.
+                */
+               coord_to_parent_coord(h->coord, &active->in_parent);
+               write_unlock_tree(h->tree);
+       }
+
+       /* check connectedness without holding tree lock---false negatives
+        * will be re-checked by connect_znode(), and false positives are
+        * impossible---@active cannot suddenly turn into unconnected
+        * state. */
+       if (!znode_is_connected(active)) {
+               h->result = connect_znode(h->coord, active);
+               if (unlikely(h->result != 0)) {
+                       put_parent(h);
+                       goto fail_or_restart;
+               }
+       }
+
+       jload_prefetch(ZJNODE(active));
+
+       if (setdk)
+               update_stale_dk(h->tree, active);
+
+       /* put_parent() cannot be called earlier, because connect_znode()
+          assumes parent node is referenced; */
+       put_parent(h);
+
+       if ((!znode_contains_key_lock(active, h->key) &&
+            (h->flags & CBK_TRUST_DK))
+           || ZF_ISSET(active, JNODE_HEARD_BANSHEE)) {
+               /* 1. key was moved out of this node while this thread was
+                  waiting for the lock. Restart. More elaborate solution is
+                  to determine where key moved (to the left, or to the right)
+                  and try to follow it through sibling pointers.
+
+                  2. or, node itself is going to be removed from the
+                  tree. Release lock and restart.
+                */
+               h->result = -E_REPEAT;
+       }
+       if (h->result == -E_REPEAT)
+               return LOOKUP_REST;
+
+       h->result = zload_ra(active, h->ra_info);
+       if (h->result) {
+               return LOOKUP_DONE;
+       }
+
+       /* sanity checks */
+       if (sanity_check(h)) {
+               zrelse(active);
+               return LOOKUP_DONE;
+       }
+
+       /* check that key of leftmost item in the @active is the same as in
+        * its parent */
+       if (ldkeyset && !node_is_empty(active) &&
+           !keyeq(leftmost_key_in_node(active, &key), &ldkey)) {
+               warning("vs-3533", "Keys are inconsistent. Fsck?");
+               reiser4_print_key("inparent", &ldkey);
+               reiser4_print_key("inchild", &key);
+               h->result = RETERR(-EIO);
+               zrelse(active);
+               return LOOKUP_DONE;
+       }
+
+       if (h->object != NULL)
+               handle_vroot(h->object, active);
+
+       ret = cbk_node_lookup(h);
+
+       /* h->active_lh->node might change, but active is yet to be zrelsed */
+       zrelse(active);
+
+       return ret;
+
+      fail_or_restart:
+       if (h->result == -E_DEADLOCK)
+               return LOOKUP_REST;
+       return LOOKUP_DONE;
+}
+
+#if REISER4_DEBUG
+/* check left and right delimiting keys of a znode */
+void check_dkeys(znode * node)
+{
+       znode *left;
+       znode *right;
+
+       read_lock_tree(current_tree);
+       read_lock_dk(current_tree);
+
+       assert("vs-1710", znode_is_any_locked(node));
+       assert("vs-1197",
+              !keygt(znode_get_ld_key(node), znode_get_rd_key(node)));
+
+       left = node->left;
+       right = node->right;
+
+       if (ZF_ISSET(node, JNODE_LEFT_CONNECTED) && ZF_ISSET(node, JNODE_DKSET)
+           && left != NULL && ZF_ISSET(left, JNODE_DKSET))
+               /* check left neighbor. Note that left neighbor is not locked,
+                  so it might get wrong delimiting keys therefore */
+               assert("vs-1198",
+                      (keyeq(znode_get_rd_key(left), znode_get_ld_key(node))
+                       || ZF_ISSET(left, JNODE_HEARD_BANSHEE)));
+
+       if (ZF_ISSET(node, JNODE_RIGHT_CONNECTED) && ZF_ISSET(node, JNODE_DKSET)
+           && right != NULL && ZF_ISSET(right, JNODE_DKSET))
+               /* check right neighbor. Note that right neighbor is not
+                  locked, so it might get wrong delimiting keys therefore  */
+               assert("vs-1199",
+                      (keyeq(znode_get_rd_key(node), znode_get_ld_key(right))
+                       || ZF_ISSET(right, JNODE_HEARD_BANSHEE)));
+
+       read_unlock_dk(current_tree);
+       read_unlock_tree(current_tree);
+}
+#endif
+
+/* true if @key is left delimiting key of @node */
+static int key_is_ld(znode * node, const reiser4_key * key)
+{
+       int ld;
+
+       assert("nikita-1716", node != NULL);
+       assert("nikita-1758", key != NULL);
+
+       read_lock_dk(znode_get_tree(node));
+       assert("nikita-1759", znode_contains_key(node, key));
+       ld = keyeq(znode_get_ld_key(node), key);
+       read_unlock_dk(znode_get_tree(node));
+       return ld;
+}
+
+/* Process one node during tree traversal.
+
+   This is called by cbk_level_lookup(). */
+static level_lookup_result cbk_node_lookup(cbk_handle * h /* search handle */ )
+{
+       /* node plugin of @active */
+       node_plugin *nplug;
+       /* item plugin of item that was found */
+       item_plugin *iplug;
+       /* search bias */
+       lookup_bias node_bias;
+       /* node we are operating upon */
+       znode *active;
+       /* tree we are searching in */
+       reiser4_tree *tree;
+       /* result */
+       int result;
+
+       assert("nikita-379", h != NULL);
+
+       active = h->active_lh->node;
+       tree = h->tree;
+
+       nplug = active->nplug;
+       assert("nikita-380", nplug != NULL);
+
+       ON_DEBUG(check_dkeys(active));
+
+       /* return item from "active" node with maximal key not greater than
+          "key"  */
+       node_bias = h->bias;
+       result = nplug->lookup(active, h->key, node_bias, h->coord);
+       if (unlikely(result != NS_FOUND && result != NS_NOT_FOUND)) {
+               /* error occurred */
+               h->result = result;
+               return LOOKUP_DONE;
+       }
+       if (h->level == h->stop_level) {
+               /* welcome to the stop level */
+               assert("nikita-381", h->coord->node == active);
+               if (result == NS_FOUND) {
+                       /* success of tree lookup */
+                       if (!(h->flags & CBK_UNIQUE)
+                           && key_is_ld(active, h->key)) {
+                               return search_to_left(h);
+                       } else
+                               h->result = CBK_COORD_FOUND;
+               } else {
+                       h->result = CBK_COORD_NOTFOUND;
+               }
+               if (!(h->flags & CBK_IN_CACHE))
+                       cbk_cache_add(active);
+               return LOOKUP_DONE;
+       }
+
+       if (h->level > TWIG_LEVEL && result == NS_NOT_FOUND) {
+               h->error = "not found on internal node";
+               h->result = result;
+               return LOOKUP_DONE;
+       }
+
+       assert("vs-361", h->level > h->stop_level);
+
+       if (handle_eottl(h, &result)) {
+               assert("vs-1674", (result == LOOKUP_DONE ||
+                                  result == LOOKUP_REST));
+               return result;
+       }
+
+       /* go down to next level */
+       check_me("vs-12", zload(h->coord->node) == 0);
+       assert("nikita-2116", item_is_internal(h->coord));
+       iplug = item_plugin_by_coord(h->coord);
+       iplug->s.internal.down_link(h->coord, h->key, &h->block);
+       zrelse(h->coord->node);
+       --h->level;
+       return LOOKUP_CONT;     /* continue */
+}
+
+/* scan cbk_cache slots looking for a match for @h */
+static int cbk_cache_scan_slots(cbk_handle * h /* cbk handle */ )
+{
+       level_lookup_result llr;
+       znode *node;
+       reiser4_tree *tree;
+       cbk_cache_slot *slot;
+       cbk_cache *cache;
+       tree_level level;
+       int isunique;
+       const reiser4_key *key;
+       int result;
+
+       assert("nikita-1317", h != NULL);
+       assert("nikita-1315", h->tree != NULL);
+       assert("nikita-1316", h->key != NULL);
+
+       tree = h->tree;
+       cache = &tree->cbk_cache;
+       if (cache->nr_slots == 0)
+               /* size of cbk cache was set to 0 by mount time option. */
+               return RETERR(-ENOENT);
+
+       assert("nikita-2474", cbk_cache_invariant(cache));
+       node = NULL;            /* to keep gcc happy */
+       level = h->level;
+       key = h->key;
+       isunique = h->flags & CBK_UNIQUE;
+       result = RETERR(-ENOENT);
+
+       /*
+        * this is time-critical function and dragons had, hence, been settled
+        * here.
+        *
+        * Loop below scans cbk cache slots trying to find matching node with
+        * suitable range of delimiting keys and located at the h->level.
+        *
+        * Scan is done under cbk cache spin lock that protects slot->node
+        * pointers. If suitable node is found we want to pin it in
+        * memory. But slot->node can point to the node with x_count 0
+        * (unreferenced). Such node can be recycled at any moment, or can
+        * already be in the process of being recycled (within jput()).
+        *
+        * As we found node in the cbk cache, it means that jput() hasn't yet
+        * called cbk_cache_invalidate().
+        *
+        * We acquire reference to the node without holding tree lock, and
+        * later, check node's RIP bit. This avoids races with jput().
+        */
+
+       rcu_read_lock();
+       read_lock(&((cbk_cache *)cache)->guard);
+
+       slot = list_entry(cache->lru.next, cbk_cache_slot, lru);
+       slot = list_entry(slot->lru.prev, cbk_cache_slot, lru);
+       BUG_ON(&slot->lru != &cache->lru);/*????*/
+       while (1) {
+
+               slot = list_entry(slot->lru.next, cbk_cache_slot, lru);
+
+               if (&cache->lru != &slot->lru)
+                       node = slot->node;
+               else
+                       node = NULL;
+
+               if (unlikely(node == NULL))
+                       break;
+
+               /*
+                * this is (hopefully) the only place in the code where we are
+                * working with delimiting keys without holding dk lock. This
+                * is fine here, because this is only "guess" anyway---keys
+                * are rechecked under dk lock below.
+                */
+               if (znode_get_level(node) == level &&
+                   /* reiser4_min_key < key < reiser4_max_key */
+                   znode_contains_key_strict(node, key, isunique)) {
+                       zref(node);
+                       result = 0;
+                       spin_lock_prefetch(&tree->tree_lock);
+                       break;
+               }
+       }
+       read_unlock(&((cbk_cache *)cache)->guard);
+
+       assert("nikita-2475", cbk_cache_invariant(cache));
+
+       if (unlikely(result == 0 && ZF_ISSET(node, JNODE_RIP)))
+               result = -ENOENT;
+
+       rcu_read_unlock();
+
+       if (result != 0) {
+               h->result = CBK_COORD_NOTFOUND;
+               return RETERR(-ENOENT);
+       }
+
+       result =
+           longterm_lock_znode(h->active_lh, node, cbk_lock_mode(level, h),
+                               ZNODE_LOCK_LOPRI);
+       zput(node);
+       if (result != 0)
+               return result;
+       result = zload(node);
+       if (result != 0)
+               return result;
+
+       /* recheck keys */
+       read_lock_dk(tree);
+       result = (znode_contains_key_strict(node, key, isunique) &&
+               !ZF_ISSET(node, JNODE_HEARD_BANSHEE));
+       read_unlock_dk(tree);
+       if (result) {
+               /* do lookup inside node */
+               llr = cbk_node_lookup(h);
+               /* if cbk_node_lookup() wandered to another node (due to eottl
+                  or non-unique keys), adjust @node */
+               /*node = h->active_lh->node; */
+
+               if (llr != LOOKUP_DONE) {
+                       /* restart or continue on the next level */
+                       result = RETERR(-ENOENT);
+               } else if (IS_CBKERR(h->result))
+                       /* io or oom */
+                       result = RETERR(-ENOENT);
+               else {
+                       /* good. Either item found or definitely not found. */
+                       result = 0;
+
+                       write_lock(&(cache->guard));
+                       if (slot->node == h->active_lh->node /*node */ ) {
+                               /* if this node is still in cbk cache---move
+                                  its slot to the head of the LRU list. */
+                               list_move(&slot->lru, &cache->lru);
+                       }
+                       write_unlock(&(cache->guard));
+               }
+       } else {
+               /* race. While this thread was waiting for the lock, node was
+                  rebalanced and item we are looking for, shifted out of it
+                  (if it ever was here).
+
+                  Continuing scanning is almost hopeless: node key range was
+                  moved to, is almost certainly at the beginning of the LRU
+                  list at this time, because it's hot, but restarting
+                  scanning from the very beginning is complex. Just return,
+                  so that cbk() will be performed. This is not that
+                  important, because such races should be rare. Are they?
+                */
+               result = RETERR(-ENOENT);       /* -ERAUGHT */
+       }
+       zrelse(node);
+       assert("nikita-2476", cbk_cache_invariant(cache));
+       return result;
+}
+
+/* look for item with given key in the coord cache
+
+   This function, called by coord_by_key(), scans "coord cache" (&cbk_cache)
+   which is a small LRU list of znodes accessed lately. For each znode in
+   znode in this list, it checks whether key we are looking for fits into key
+   range covered by this node. If so, and in addition, node lies at allowed
+   level (this is to handle extents on a twig level), node is locked, and
+   lookup inside it is performed.
+
+   we need a measurement of the cost of this cache search compared to the cost
+   of coord_by_key.
+
+*/
+static int cbk_cache_search(cbk_handle * h /* cbk handle */ )
+{
+       int result = 0;
+       tree_level level;
+
+       /* add CBK_IN_CACHE to the handle flags. This means that
+        * cbk_node_lookup() assumes that cbk_cache is scanned and would add
+        * found node to the cache. */
+       h->flags |= CBK_IN_CACHE;
+       for (level = h->stop_level; level <= h->lock_level; ++level) {
+               h->level = level;
+               result = cbk_cache_scan_slots(h);
+               if (result != 0) {
+                       done_lh(h->active_lh);
+                       done_lh(h->parent_lh);
+               } else {
+                       assert("nikita-1319", !IS_CBKERR(h->result));
+                       break;
+               }
+       }
+       h->flags &= ~CBK_IN_CACHE;
+       return result;
+}
+
+/* type of lock we want to obtain during tree traversal. On stop level
+    we want type of lock user asked for, on upper levels: read lock. */
+znode_lock_mode cbk_lock_mode(tree_level level, cbk_handle * h)
+{
+       assert("nikita-382", h != NULL);
+
+       return (level <= h->lock_level) ? h->lock_mode : ZNODE_READ_LOCK;
+}
+
+/* update outdated delimiting keys */
+static void stale_dk(reiser4_tree * tree, znode * node)
+{
+       znode *right;
+
+       read_lock_tree(tree);
+       write_lock_dk(tree);
+       right = node->right;
+
+       if (ZF_ISSET(node, JNODE_RIGHT_CONNECTED) &&
+           right && ZF_ISSET(right, JNODE_DKSET) &&
+           !keyeq(znode_get_rd_key(node), znode_get_ld_key(right)))
+               znode_set_rd_key(node, znode_get_ld_key(right));
+
+       write_unlock_dk(tree);
+       read_unlock_tree(tree);
+}
+
+/* check for possibly outdated delimiting keys, and update them if
+ * necessary. */
+static void update_stale_dk(reiser4_tree * tree, znode * node)
+{
+       znode *right;
+       reiser4_key rd;
+
+       read_lock_tree(tree);
+       read_lock_dk(tree);
+       rd = *znode_get_rd_key(node);
+       right = node->right;
+       if (unlikely(ZF_ISSET(node, JNODE_RIGHT_CONNECTED) &&
+                    right && ZF_ISSET(right, JNODE_DKSET) &&
+                    !keyeq(&rd, znode_get_ld_key(right)))) {
+               assert("nikita-38211", ZF_ISSET(node, JNODE_DKSET));
+               read_unlock_dk(tree);
+               read_unlock_tree(tree);
+               stale_dk(tree, node);
+               return;
+       }
+       read_unlock_dk(tree);
+       read_unlock_tree(tree);
+}
+
+/*
+ * handle searches a the non-unique key.
+ *
+ * Suppose that we are looking for an item with possibly non-unique key 100.
+ *
+ * Root node contains two pointers: one to a node with left delimiting key 0,
+ * and another to a node with left delimiting key 100. Item we interested in
+ * may well happen in the sub-tree rooted at the first pointer.
+ *
+ * To handle this search_to_left() is called when search reaches stop
+ * level. This function checks it is _possible_ that item we are looking for
+ * is in the left neighbor (this can be done by comparing delimiting keys) and
+ * if so, tries to lock left neighbor (this is low priority lock, so it can
+ * deadlock, tree traversal is just restarted if it did) and then checks
+ * whether left neighbor actually contains items with our key.
+ *
+ * Note that this is done on the stop level only. It is possible to try such
+ * left-check on each level, but as duplicate keys are supposed to be rare
+ * (very unlikely that more than one node is completely filled with items with
+ * duplicate keys), it sis cheaper to scan to the left on the stop level once.
+ *
+ */
+static level_lookup_result search_to_left(cbk_handle * h /* search handle */ )
+{
+       level_lookup_result result;
+       coord_t *coord;
+       znode *node;
+       znode *neighbor;
+
+       lock_handle lh;
+
+       assert("nikita-1761", h != NULL);
+       assert("nikita-1762", h->level == h->stop_level);
+
+       init_lh(&lh);
+       coord = h->coord;
+       node = h->active_lh->node;
+       assert("nikita-1763", coord_is_leftmost_unit(coord));
+
+       h->result =
+           reiser4_get_left_neighbor(&lh, node, (int)h->lock_mode,
+                                     GN_CAN_USE_UPPER_LEVELS);
+       neighbor = NULL;
+       switch (h->result) {
+       case -E_DEADLOCK:
+               result = LOOKUP_REST;
+               break;
+       case 0:{
+                       node_plugin *nplug;
+                       coord_t crd;
+                       lookup_bias bias;
+
+                       neighbor = lh.node;
+                       h->result = zload(neighbor);
+                       if (h->result != 0) {
+                               result = LOOKUP_DONE;
+                               break;
+                       }
+
+                       nplug = neighbor->nplug;
+
+                       coord_init_zero(&crd);
+                       bias = h->bias;
+                       h->bias = FIND_EXACT;
+                       h->result =
+                           nplug->lookup(neighbor, h->key, h->bias, &crd);
+                       h->bias = bias;
+
+                       if (h->result == NS_NOT_FOUND) {
+       case -E_NO_NEIGHBOR:
+                               h->result = CBK_COORD_FOUND;
+                               if (!(h->flags & CBK_IN_CACHE))
+                                       cbk_cache_add(node);
+       default:                /* some other error */
+                               result = LOOKUP_DONE;
+                       } else if (h->result == NS_FOUND) {
+                               read_lock_dk(znode_get_tree(neighbor));
+                               h->rd_key = *znode_get_ld_key(node);
+                               leftmost_key_in_node(neighbor, &h->ld_key);
+                               read_unlock_dk(znode_get_tree(neighbor));
+                               h->flags |= CBK_DKSET;
+
+                               h->block = *znode_get_block(neighbor);
+                               /* clear coord -> node so that cbk_level_lookup()
+                                  wouldn't overwrite parent hint in neighbor.
+
+                                  Parent hint was set up by
+                                  reiser4_get_left_neighbor()
+                                */
+                               /* FIXME: why do we have to spinlock here? */
+                               write_lock_tree(znode_get_tree(neighbor));
+                               h->coord->node = NULL;
+                               write_unlock_tree(znode_get_tree(neighbor));
+                               result = LOOKUP_CONT;
+                       } else {
+                               result = LOOKUP_DONE;
+                       }
+                       if (neighbor != NULL)
+                               zrelse(neighbor);
+               }
+       }
+       done_lh(&lh);
+       return result;
+}
+
+/* debugging aid: return symbolic name of search bias */
+static const char *bias_name(lookup_bias bias /* bias to get name of */ )
+{
+       if (bias == FIND_EXACT)
+               return "exact";
+       else if (bias == FIND_MAX_NOT_MORE_THAN)
+               return "left-slant";
+/*     else if( bias == RIGHT_SLANT_BIAS ) */
+/*             return "right-bias"; */
+       else {
+               static char buf[30];
+
+               sprintf(buf, "unknown: %i", bias);
+               return buf;
+       }
+}
+
+#if REISER4_DEBUG
+/* debugging aid: print human readable information about @p */
+void print_coord_content(const char *prefix /* prefix to print */ ,
+                        coord_t * p /* coord to print */ )
+{
+       reiser4_key key;
+
+       if (p == NULL) {
+               printk("%s: null\n", prefix);
+               return;
+       }
+       if ((p->node != NULL) && znode_is_loaded(p->node)
+           && coord_is_existing_item(p))
+               printk("%s: data: %p, length: %i\n", prefix,
+                      item_body_by_coord(p), item_length_by_coord(p));
+       if (znode_is_loaded(p->node)) {
+               item_key_by_coord(p, &key);
+               reiser4_print_key(prefix, &key);
+       }
+}
+
+/* debugging aid: print human readable information about @block */
+void reiser4_print_address(const char *prefix /* prefix to print */ ,
+                  const reiser4_block_nr * block /* block number to print */ )
+{
+       printk("%s: %s\n", prefix, sprint_address(block));
+}
+#endif
+
+/* return string containing human readable representation of @block */
+char *sprint_address(const reiser4_block_nr *
+                    block /* block number to print */ )
+{
+       static char address[30];
+
+       if (block == NULL)
+               sprintf(address, "null");
+       else if (reiser4_blocknr_is_fake(block))
+               sprintf(address, "%llx", (unsigned long long)(*block));
+       else
+               sprintf(address, "%llu", (unsigned long long)(*block));
+       return address;
+}
+
+/* release parent node during traversal */
+static void put_parent(cbk_handle * h /* search handle */ )
+{
+       assert("nikita-383", h != NULL);
+       if (h->parent_lh->node != NULL) {
+               longterm_unlock_znode(h->parent_lh);
+       }
+}
+
+/* helper function used by coord_by_key(): release reference to parent znode
+   stored in handle before processing its child. */
+static void hput(cbk_handle * h /* search handle */ )
+{
+       assert("nikita-385", h != NULL);
+       done_lh(h->parent_lh);
+       done_lh(h->active_lh);
+}
+
+/* Helper function used by cbk(): update delimiting keys of child node (stored
+   in h->active_lh->node) using key taken from parent on the parent level. */
+static int setup_delimiting_keys(cbk_handle * h /* search handle */ )
+{
+       znode *active;
+       reiser4_tree *tree;
+
+       assert("nikita-1088", h != NULL);
+
+       active = h->active_lh->node;
+
+       /* fast check without taking dk lock. This is safe, because
+        * JNODE_DKSET is never cleared once set. */
+       if (!ZF_ISSET(active, JNODE_DKSET)) {
+               tree = znode_get_tree(active);
+               write_lock_dk(tree);
+               if (!ZF_ISSET(active, JNODE_DKSET)) {
+                       znode_set_ld_key(active, &h->ld_key);
+                       znode_set_rd_key(active, &h->rd_key);
+                       ZF_SET(active, JNODE_DKSET);
+               }
+               write_unlock_dk(tree);
+               return 1;
+       }
+       return 0;
+}
+
+/* true if @block makes sense for the @tree. Used to detect corrupted node
+ * pointers */
+static int
+block_nr_is_correct(reiser4_block_nr * block /* block number to check */ ,
+                   reiser4_tree * tree /* tree to check against */ )
+{
+       assert("nikita-757", block != NULL);
+       assert("nikita-758", tree != NULL);
+
+       /* check to see if it exceeds the size of the device. */
+       return reiser4_blocknr_is_sane_for(tree->super, block);
+}
+
+/* check consistency of fields */
+static int sanity_check(cbk_handle * h /* search handle */ )
+{
+       assert("nikita-384", h != NULL);
+
+       if (h->level < h->stop_level) {
+               h->error = "Buried under leaves";
+               h->result = RETERR(-EIO);
+               return LOOKUP_DONE;
+       } else if (!block_nr_is_correct(&h->block, h->tree)) {
+               h->error = "bad block number";
+               h->result = RETERR(-EIO);
+               return LOOKUP_DONE;
+       } else
+               return 0;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/status_flags.c linux-2.6.20/fs/reiser4/status_flags.c
--- linux-2.6.20.orig/fs/reiser4/status_flags.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/status_flags.c      2007-05-06 14:50:43.875030717 +0400
@@ -0,0 +1,175 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Functions that deal with reiser4 status block, query status and update it, if needed */
+
+#include <linux/bio.h>
+#include <linux/highmem.h>
+#include <linux/fs.h>
+#include <linux/blkdev.h>
+#include "debug.h"
+#include "dformat.h"
+#include "status_flags.h"
+#include "super.h"
+
+/* This is our end I/O handler that marks page uptodate if IO was successful. It also
+   unconditionally unlocks the page, so we can see that io was done.
+   We do not free bio, because we hope to reuse that. */
+static int reiser4_status_endio(struct bio *bio, unsigned int bytes_done,
+                               int err)
+{
+       if (bio->bi_size)
+               return 1;
+
+       if (test_bit(BIO_UPTODATE, &bio->bi_flags)) {
+               SetPageUptodate(bio->bi_io_vec->bv_page);
+       } else {
+               ClearPageUptodate(bio->bi_io_vec->bv_page);
+               SetPageError(bio->bi_io_vec->bv_page);
+       }
+       unlock_page(bio->bi_io_vec->bv_page);
+       return 0;
+}
+
+/* Initialise status code. This is expected to be called from the disk format
+   code. block paremeter is where status block lives. */
+int reiser4_status_init(reiser4_block_nr block)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+       struct reiser4_status *statuspage;
+       struct bio *bio;
+       struct page *page;
+
+       get_super_private(sb)->status_page = NULL;
+       get_super_private(sb)->status_bio = NULL;
+
+       page = alloc_pages(reiser4_ctx_gfp_mask_get(), 0);
+       if (!page)
+               return -ENOMEM;
+
+       bio = bio_alloc(reiser4_ctx_gfp_mask_get(), 1);
+       if (bio != NULL) {
+               bio->bi_sector = block * (sb->s_blocksize >> 9);
+               bio->bi_bdev = sb->s_bdev;
+               bio->bi_io_vec[0].bv_page = page;
+               bio->bi_io_vec[0].bv_len = sb->s_blocksize;
+               bio->bi_io_vec[0].bv_offset = 0;
+               bio->bi_vcnt = 1;
+               bio->bi_size = sb->s_blocksize;
+               bio->bi_end_io = reiser4_status_endio;
+       } else {
+               __free_pages(page, 0);
+               return -ENOMEM;
+       }
+       lock_page(page);
+       submit_bio(READ, bio);
+       blk_run_address_space(reiser4_get_super_fake(sb)->i_mapping);
+       wait_on_page_locked(page);
+       if (!PageUptodate(page)) {
+               warning("green-2007",
+                       "I/O error while tried to read status page\n");
+               return -EIO;
+       }
+
+       statuspage = (struct reiser4_status *)kmap_atomic(page, KM_USER0);
+       if (memcmp
+           (statuspage->magic, REISER4_STATUS_MAGIC,
+            sizeof(REISER4_STATUS_MAGIC))) {
+               /* Magic does not match. */
+               kunmap_atomic((char *)statuspage, KM_USER0);
+               warning("green-2008", "Wrong magic in status block\n");
+               __free_pages(page, 0);
+               bio_put(bio);
+               return -EINVAL;
+       }
+       kunmap_atomic((char *)statuspage, KM_USER0);
+
+       get_super_private(sb)->status_page = page;
+       get_super_private(sb)->status_bio = bio;
+       return 0;
+}
+
+/* Query the status of fs. Returns if the FS can be safely mounted.
+   Also if "status" and "extended" parameters are given, it will fill
+   actual parts of status from disk there. */
+int reiser4_status_query(u64 * status, u64 * extended)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+       struct reiser4_status *statuspage;
+       int retval;
+
+       if (!get_super_private(sb)->status_page) {      // No status page?
+               return REISER4_STATUS_MOUNT_UNKNOWN;
+       }
+       statuspage = (struct reiser4_status *)
+           kmap_atomic(get_super_private(sb)->status_page, KM_USER0);
+       switch ((long)le64_to_cpu(get_unaligned(&statuspage->status))) {        // FIXME: this cast is a hack for 32 bit arches to work.
+       case REISER4_STATUS_OK:
+               retval = REISER4_STATUS_MOUNT_OK;
+               break;
+       case REISER4_STATUS_CORRUPTED:
+               retval = REISER4_STATUS_MOUNT_WARN;
+               break;
+       case REISER4_STATUS_DAMAGED:
+       case REISER4_STATUS_DESTROYED:
+       case REISER4_STATUS_IOERROR:
+               retval = REISER4_STATUS_MOUNT_RO;
+               break;
+       default:
+               retval = REISER4_STATUS_MOUNT_UNKNOWN;
+               break;
+       }
+
+       if (status)
+               *status = le64_to_cpu(get_unaligned(&statuspage->status));
+       if (extended)
+               *extended = le64_to_cpu(get_unaligned(&statuspage->extended_status));
+
+       kunmap_atomic((char *)statuspage, KM_USER0);
+       return retval;
+}
+
+/* This function should be called when something bad happens (e.g. from reiser4_panic).
+   It fills the status structure and tries to push it to disk. */
+int reiser4_status_write(__u64 status, __u64 extended_status, char *message)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+       struct reiser4_status *statuspage;
+       struct bio *bio = get_super_private(sb)->status_bio;
+
+       if (!get_super_private(sb)->status_page) {      // No status page?
+               return -1;
+       }
+       statuspage = (struct reiser4_status *)
+           kmap_atomic(get_super_private(sb)->status_page, KM_USER0);
+
+       put_unaligned(cpu_to_le64(status), &statuspage->status);
+       put_unaligned(cpu_to_le64(extended_status), &statuspage->extended_status);
+       strncpy(statuspage->texterror, message, REISER4_TEXTERROR_LEN);
+
+       kunmap_atomic((char *)statuspage, KM_USER0);
+       bio->bi_bdev = sb->s_bdev;
+       bio->bi_io_vec[0].bv_page = get_super_private(sb)->status_page;
+       bio->bi_io_vec[0].bv_len = sb->s_blocksize;
+       bio->bi_io_vec[0].bv_offset = 0;
+       bio->bi_vcnt = 1;
+       bio->bi_size = sb->s_blocksize;
+       bio->bi_end_io = reiser4_status_endio;
+       lock_page(get_super_private(sb)->status_page);  // Safe as nobody should touch our page.
+       /* We can block now, but we have no other choice anyway */
+       submit_bio(WRITE, bio);
+       blk_run_address_space(reiser4_get_super_fake(sb)->i_mapping);
+       return 0;               // We do not wait for io to finish.
+}
+
+/* Frees the page with status and bio structure. Should be called by disk format at umount time */
+int reiser4_status_finish(void)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+
+       __free_pages(get_super_private(sb)->status_page, 0);
+       get_super_private(sb)->status_page = NULL;
+       bio_put(get_super_private(sb)->status_bio);
+       get_super_private(sb)->status_bio = NULL;
+       return 0;
+}
diff -urN linux-2.6.20.orig/fs/reiser4/status_flags.h linux-2.6.20/fs/reiser4/status_flags.h
--- linux-2.6.20.orig/fs/reiser4/status_flags.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/status_flags.h      2007-05-06 14:50:43.875030717 +0400
@@ -0,0 +1,43 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Here we declare structures and flags that store reiser4 status on disk.
+   The status that helps us to find out if the filesystem is valid or if it
+   contains some critical, or not so critical errors */
+
+#if !defined( __REISER4_STATUS_FLAGS_H__ )
+#define __REISER4_STATUS_FLAGS_H__
+
+#include "dformat.h"
+/* These are major status flags */
+#define REISER4_STATUS_OK 0
+#define REISER4_STATUS_CORRUPTED 0x1
+#define REISER4_STATUS_DAMAGED 0x2
+#define REISER4_STATUS_DESTROYED 0x4
+#define REISER4_STATUS_IOERROR 0x8
+
+/* Return values for reiser4_status_query() */
+#define REISER4_STATUS_MOUNT_OK 0
+#define REISER4_STATUS_MOUNT_WARN 1
+#define REISER4_STATUS_MOUNT_RO 2
+#define REISER4_STATUS_MOUNT_UNKNOWN -1
+
+#define REISER4_TEXTERROR_LEN 256
+
+#define REISER4_STATUS_MAGIC "ReiSeR4StATusBl"
+/* We probably need to keep its size under sector size which is 512 bytes */
+struct reiser4_status {
+       char magic[16];
+       d64 status;             /* Current FS state */
+       d64 extended_status;    /* Any additional info that might have sense in addition to "status". E.g.
+                                  last sector where io error happened if status is "io error encountered" */
+       d64 stacktrace[10];     /* Last ten functional calls made (addresses) */
+       char texterror[REISER4_TEXTERROR_LEN];  /* Any error message if appropriate, otherwise filled with zeroes */
+};
+
+int reiser4_status_init(reiser4_block_nr block);
+int reiser4_status_query(u64 * status, u64 * extended);
+int reiser4_status_write(u64 status, u64 extended_status, char *message);
+int reiser4_status_finish(void);
+
+#endif
diff -urN linux-2.6.20.orig/fs/reiser4/super.c linux-2.6.20/fs/reiser4/super.c
--- linux-2.6.20.orig/fs/reiser4/super.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/super.c     2007-05-06 14:50:43.875030717 +0400
@@ -0,0 +1,316 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Super-block manipulations. */
+
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "plugin/security/perm.h"
+#include "plugin/space/space_allocator.h"
+#include "plugin/plugin.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+
+static __u64 reserved_for_gid(const struct super_block *super, gid_t gid);
+static __u64 reserved_for_uid(const struct super_block *super, uid_t uid);
+static __u64 reserved_for_root(const struct super_block *super);
+
+/* Return reiser4-specific part of super block */
+reiser4_super_info_data *get_super_private_nocheck(const struct super_block *super     /* super block
+                                                                                        * queried */ )
+{
+       return (reiser4_super_info_data *) super->s_fs_info;
+}
+
+/* Return reiser4 fstype: value that is returned in ->f_type field by statfs() */
+long reiser4_statfs_type(const struct super_block *super UNUSED_ARG)
+{
+       assert("nikita-448", super != NULL);
+       assert("nikita-449", is_reiser4_super(super));
+       return (long)REISER4_SUPER_MAGIC;
+}
+
+/* functions to read/modify fields of reiser4_super_info_data */
+
+/* get number of blocks in file system */
+__u64 reiser4_block_count(const struct super_block *super      /* super block
+                                                                  queried */ )
+{
+       assert("vs-494", super != NULL);
+       assert("vs-495", is_reiser4_super(super));
+       return get_super_private(super)->block_count;
+}
+
+#if REISER4_DEBUG
+/*
+ * number of blocks in the current file system
+ */
+__u64 reiser4_current_block_count(void)
+{
+       return get_current_super_private()->block_count;
+}
+#endif  /*  REISER4_DEBUG  */
+
+/* set number of block in filesystem */
+void reiser4_set_block_count(const struct super_block *super, __u64 nr)
+{
+       assert("vs-501", super != NULL);
+       assert("vs-502", is_reiser4_super(super));
+       get_super_private(super)->block_count = nr;
+       /*
+        * The proper calculation of the reserved space counter (%5 of device
+        * block counter) we need a 64 bit division which is missing in Linux
+        * on i386 platform. Because we do not need a precise calculation here
+        * we can replace a div64 operation by this combination of
+        * multiplication and shift: 51. / (2^10) == .0498 .
+        * FIXME: this is a bug. It comes up only for very small filesystems
+        * which probably are never used. Nevertheless, it is a bug. Number of
+        * reserved blocks must be not less than maximal number of blocks which
+        * get grabbed with BA_RESERVED.
+        */
+       get_super_private(super)->blocks_reserved = ((nr * 51) >> 10);
+}
+
+/* amount of blocks used (allocated for data) in file system */
+__u64 reiser4_data_blocks(const struct super_block *super      /* super block
+                                                                  queried */ )
+{
+       assert("nikita-452", super != NULL);
+       assert("nikita-453", is_reiser4_super(super));
+       return get_super_private(super)->blocks_used;
+}
+
+/* set number of block used in filesystem */
+void reiser4_set_data_blocks(const struct super_block *super, __u64 nr)
+{
+       assert("vs-503", super != NULL);
+       assert("vs-504", is_reiser4_super(super));
+       get_super_private(super)->blocks_used = nr;
+}
+
+/* amount of free blocks in file system */
+__u64 reiser4_free_blocks(const struct super_block *super      /* super block
+                                                                  queried */ )
+{
+       assert("nikita-454", super != NULL);
+       assert("nikita-455", is_reiser4_super(super));
+       return get_super_private(super)->blocks_free;
+}
+
+/* set number of blocks free in filesystem */
+void reiser4_set_free_blocks(const struct super_block *super, __u64 nr)
+{
+       assert("vs-505", super != NULL);
+       assert("vs-506", is_reiser4_super(super));
+       get_super_private(super)->blocks_free = nr;
+}
+
+/* get mkfs unique identifier */
+__u32 reiser4_mkfs_id(const struct super_block *super  /* super block
+                                                          queried */ )
+{
+       assert("vpf-221", super != NULL);
+       assert("vpf-222", is_reiser4_super(super));
+       return get_super_private(super)->mkfs_id;
+}
+
+/* amount of free blocks in file system */
+__u64 reiser4_free_committed_blocks(const struct super_block *super)
+{
+       assert("vs-497", super != NULL);
+       assert("vs-498", is_reiser4_super(super));
+       return get_super_private(super)->blocks_free_committed;
+}
+
+/* amount of blocks in the file system reserved for @uid and @gid */
+long reiser4_reserved_blocks(const struct super_block *super   /* super block
+                                                                  queried */ ,
+                            uid_t uid /* user id */ ,
+                            gid_t gid /* group id */ )
+{
+       long reserved;
+
+       assert("nikita-456", super != NULL);
+       assert("nikita-457", is_reiser4_super(super));
+
+       reserved = 0;
+       if (REISER4_SUPPORT_GID_SPACE_RESERVATION)
+               reserved += reserved_for_gid(super, gid);
+       if (REISER4_SUPPORT_UID_SPACE_RESERVATION)
+               reserved += reserved_for_uid(super, uid);
+       if (REISER4_SUPPORT_ROOT_SPACE_RESERVATION && (uid == 0))
+               reserved += reserved_for_root(super);
+       return reserved;
+}
+
+/* get/set value of/to grabbed blocks counter */
+__u64 reiser4_grabbed_blocks(const struct super_block * super)
+{
+       assert("zam-512", super != NULL);
+       assert("zam-513", is_reiser4_super(super));
+
+       return get_super_private(super)->blocks_grabbed;
+}
+
+__u64 reiser4_flush_reserved(const struct super_block * super)
+{
+       assert("vpf-285", super != NULL);
+       assert("vpf-286", is_reiser4_super(super));
+
+       return get_super_private(super)->blocks_flush_reserved;
+}
+
+/* get/set value of/to counter of fake allocated formatted blocks */
+__u64 reiser4_fake_allocated(const struct super_block * super)
+{
+       assert("zam-516", super != NULL);
+       assert("zam-517", is_reiser4_super(super));
+
+       return get_super_private(super)->blocks_fake_allocated;
+}
+
+/* get/set value of/to counter of fake allocated unformatted blocks */
+__u64 reiser4_fake_allocated_unformatted(const struct super_block * super)
+{
+       assert("zam-516", super != NULL);
+       assert("zam-517", is_reiser4_super(super));
+
+       return get_super_private(super)->blocks_fake_allocated_unformatted;
+}
+
+/* get/set value of/to counter of clustered blocks */
+__u64 reiser4_clustered_blocks(const struct super_block * super)
+{
+       assert("edward-601", super != NULL);
+       assert("edward-602", is_reiser4_super(super));
+
+       return get_super_private(super)->blocks_clustered;
+}
+
+/* space allocator used by this file system */
+reiser4_space_allocator * reiser4_get_space_allocator(const struct super_block
+                                                     *super)
+{
+       assert("nikita-1965", super != NULL);
+       assert("nikita-1966", is_reiser4_super(super));
+       return &get_super_private(super)->space_allocator;
+}
+
+/* return fake inode used to bind formatted nodes in the page cache */
+struct inode *reiser4_get_super_fake(const struct super_block *super   /* super block
+                                                                  queried */ )
+{
+       assert("nikita-1757", super != NULL);
+       return get_super_private(super)->fake;
+}
+
+/* return fake inode used to bind copied on capture nodes in the page cache */
+struct inode *reiser4_get_cc_fake(const struct super_block *super      /* super block
+                                                                  queried */ )
+{
+       assert("nikita-1757", super != NULL);
+       return get_super_private(super)->cc;
+}
+
+/* return fake inode used to bind bitmaps and journlal heads */
+struct inode *reiser4_get_bitmap_fake(const struct super_block *super)
+{
+       assert("nikita-17571", super != NULL);
+       return get_super_private(super)->bitmap;
+}
+
+/* tree used by this file system */
+reiser4_tree *reiser4_get_tree(const struct super_block * super        /* super block
+                                                        * queried */ )
+{
+       assert("nikita-460", super != NULL);
+       assert("nikita-461", is_reiser4_super(super));
+       return &get_super_private(super)->tree;
+}
+
+/* Check that @super is (looks like) reiser4 super block. This is mainly for
+   use in assertions. */
+int is_reiser4_super(const struct super_block *super   /* super block
+                                                        * queried */ )
+{
+       return
+           super != NULL &&
+           get_super_private(super) != NULL &&
+           super->s_op == &(get_super_private(super)->ops.super);
+}
+
+int reiser4_is_set(const struct super_block *super, reiser4_fs_flag f)
+{
+       return test_bit((int)f, &get_super_private(super)->fs_flags);
+}
+
+/* amount of blocks reserved for given group in file system */
+static __u64 reserved_for_gid(const struct super_block *super UNUSED_ARG       /* super
+                                                                                * block
+                                                                                * queried */ ,
+                             gid_t gid UNUSED_ARG /* group id */ )
+{
+       return 0;
+}
+
+/* amount of blocks reserved for given user in file system */
+static __u64 reserved_for_uid(const struct super_block *super UNUSED_ARG       /* super
+                                                                                  block
+                                                                                  queried */ ,
+                             uid_t uid UNUSED_ARG /* user id */ )
+{
+       return 0;
+}
+
+/* amount of blocks reserved for super user in file system */
+static __u64 reserved_for_root(const struct super_block *super UNUSED_ARG      /* super
+                                                                                  block
+                                                                                  queried */ )
+{
+       return 0;
+}
+
+/*
+ * true if block number @blk makes sense for the file system at @super.
+ */
+int
+reiser4_blocknr_is_sane_for(const struct super_block *super,
+                           const reiser4_block_nr * blk)
+{
+       reiser4_super_info_data *sbinfo;
+
+       assert("nikita-2957", super != NULL);
+       assert("nikita-2958", blk != NULL);
+
+       if (reiser4_blocknr_is_fake(blk))
+               return 1;
+
+       sbinfo = get_super_private(super);
+       return *blk < sbinfo->block_count;
+}
+
+#if REISER4_DEBUG
+/*
+ * true, if block number @blk makes sense for the current file system
+ */
+int reiser4_blocknr_is_sane(const reiser4_block_nr * blk)
+{
+       return reiser4_blocknr_is_sane_for(reiser4_get_current_sb(), blk);
+}
+#endif  /*  REISER4_DEBUG  */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/super.h linux-2.6.20/fs/reiser4/super.h
--- linux-2.6.20.orig/fs/reiser4/super.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/super.h     2007-05-06 14:50:43.875030717 +0400
@@ -0,0 +1,464 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Super-block functions. See super.c for details. */
+
+#if !defined( __REISER4_SUPER_H__ )
+#define __REISER4_SUPER_H__
+
+#include "tree.h"
+#include "entd.h"
+#include "wander.h"
+#include "fsdata.h"
+#include "plugin/object.h"
+#include "plugin/space/space_allocator.h"
+
+/*
+ * Flush algorithms parameters.
+ */
+typedef struct {
+       unsigned relocate_threshold;
+       unsigned relocate_distance;
+       unsigned written_threshold;
+       unsigned scan_maxnodes;
+} flush_params;
+
+typedef enum {
+       /*
+        * True if this file system doesn't support hard-links (multiple names)
+        * for directories: this is default UNIX behavior.
+        *
+        * If hard-links on directoires are not allowed, file system is Acyclic
+        * Directed Graph (modulo dot, and dotdot, of course).
+        *
+        * This is used by reiser4_link().
+        */
+       REISER4_ADG = 0,
+       /*
+        * set if all nodes in internal tree have the same node layout plugin.
+        * If so, znode_guess_plugin() will return tree->node_plugin in stead
+        * of guessing plugin by plugin id stored in the node.
+        */
+       REISER4_ONE_NODE_PLUGIN = 1,
+       /* if set, bsd gid assignment is supported. */
+       REISER4_BSD_GID = 2,
+       /* [mac]_time are 32 bit in inode */
+       REISER4_32_BIT_TIMES = 3,
+       /* load all bitmap blocks at mount time */
+       REISER4_DONT_LOAD_BITMAP = 5,
+       /* enforce atomicity during write(2) */
+       REISER4_ATOMIC_WRITE = 6,
+       /* don't use write barriers in the log writer code. */
+       REISER4_NO_WRITE_BARRIER = 7
+} reiser4_fs_flag;
+
+/*
+ * VFS related operation vectors.
+ */
+typedef struct object_ops {
+       struct super_operations super;
+       struct dentry_operations dentry;
+       struct export_operations export;
+} object_ops;
+
+/* reiser4-specific part of super block
+
+   Locking
+
+   Fields immutable after mount:
+
+    ->oid*
+    ->space*
+    ->default_[ug]id
+    ->mkfs_id
+    ->trace_flags
+    ->debug_flags
+    ->fs_flags
+    ->df_plug
+    ->optimal_io_size
+    ->plug
+    ->flush
+    ->u (bad name)
+    ->txnmgr
+    ->ra_params
+    ->fsuid
+    ->journal_header
+    ->journal_footer
+
+   Fields protected by ->lnode_guard
+
+    ->lnode_htable
+
+   Fields protected by per-super block spin lock
+
+    ->block_count
+    ->blocks_used
+    ->blocks_free
+    ->blocks_free_committed
+    ->blocks_grabbed
+    ->blocks_fake_allocated_unformatted
+    ->blocks_fake_allocated
+    ->blocks_flush_reserved
+    ->eflushed
+    ->blocknr_hint_default
+
+   After journal replaying during mount,
+
+    ->last_committed_tx
+
+   is protected by ->tmgr.commit_mutex
+
+   Invariants involving this data-type:
+
+      [sb-block-counts]
+      [sb-grabbed]
+      [sb-fake-allocated]
+*/
+struct reiser4_super_info_data {
+       /*
+        * guard spinlock which protects reiser4 super block fields (currently
+        * blocks_free, blocks_free_committed)
+        */
+       spinlock_t guard;
+
+       /* next oid that will be returned by oid_allocate() */
+       oid_t next_to_use;
+       /* total number of used oids */
+       oid_t oids_in_use;
+
+       /* space manager plugin */
+       reiser4_space_allocator space_allocator;
+
+       /* reiser4 internal tree */
+       reiser4_tree tree;
+
+       /*
+        * default user id used for light-weight files without their own
+        * stat-data.
+        */
+       uid_t default_uid;
+
+       /*
+        * default group id used for light-weight files without their own
+        * stat-data.
+        */
+       gid_t default_gid;
+
+       /* mkfs identifier generated at mkfs time. */
+       __u32 mkfs_id;
+       /* amount of blocks in a file system */
+       __u64 block_count;
+
+       /* inviolable reserve */
+       __u64 blocks_reserved;
+
+       /* amount of blocks used by file system data and meta-data. */
+       __u64 blocks_used;
+
+       /*
+        * amount of free blocks. This is "working" free blocks counter. It is
+        * like "working" bitmap, please see block_alloc.c for description.
+        */
+       __u64 blocks_free;
+
+       /*
+        * free block count for fs committed state. This is "commit" version of
+        * free block counter.
+        */
+       __u64 blocks_free_committed;
+
+       /*
+        * number of blocks reserved for further allocation, for all
+        * threads.
+        */
+       __u64 blocks_grabbed;
+
+       /* number of fake allocated unformatted blocks in tree. */
+       __u64 blocks_fake_allocated_unformatted;
+
+       /* number of fake allocated formatted blocks in tree. */
+       __u64 blocks_fake_allocated;
+
+       /* number of blocks reserved for flush operations. */
+       __u64 blocks_flush_reserved;
+
+       /* number of blocks reserved for cluster operations. */
+       __u64 blocks_clustered;
+
+       /* unique file-system identifier */
+       __u32 fsuid;
+
+       /* On-disk format version. If does not equal to the disk_format
+          plugin version, some format updates (e.g. enlarging plugin
+          set, etc) may have place on mount. */
+       int version;
+
+       /* file-system wide flags. See reiser4_fs_flag enum */
+       unsigned long fs_flags;
+
+       /* transaction manager */
+       txn_mgr tmgr;
+
+       /* ent thread */
+       entd_context entd;
+
+       /* fake inode used to bind formatted nodes */
+       struct inode *fake;
+       /* inode used to bind bitmaps (and journal heads) */
+       struct inode *bitmap;
+       /* inode used to bind copied on capture nodes */
+       struct inode *cc;
+
+       /* disk layout plugin */
+       disk_format_plugin *df_plug;
+
+       /* disk layout specific part of reiser4 super info data */
+       union {
+               format40_super_info format40;
+       } u;
+
+       /* value we return in st_blksize on stat(2) */
+       unsigned long optimal_io_size;
+
+       /* parameters for the flush algorithm */
+       flush_params flush;
+
+       /* pointers to jnodes for journal header and footer */
+       jnode *journal_header;
+       jnode *journal_footer;
+
+       journal_location jloc;
+
+       /* head block number of last committed transaction */
+       __u64 last_committed_tx;
+
+       /*
+        * we remember last written location for using as a hint for new block
+        * allocation
+        */
+       __u64 blocknr_hint_default;
+
+       /* committed number of files (oid allocator state variable ) */
+       __u64 nr_files_committed;
+
+       ra_params_t ra_params;
+
+       /*
+        * A mutex for serializing cut tree operation if out-of-free-space:
+        * the only one cut_tree thread is allowed to grab space from reserved
+        * area (it is 5% of disk space)
+        */
+       struct mutex delete_mutex;
+       /* task owning ->delete_mutex */
+       struct task_struct *delete_mutex_owner;
+
+       /* Diskmap's blocknumber */
+       __u64 diskmap_block;
+
+       /* What to do in case of error */
+       int onerror;
+
+       /* operations for objects on this file system */
+       object_ops ops;
+
+       /*
+        * structure to maintain d_cursors. See plugin/file_ops_readdir.c for
+        * more details
+        */
+       d_cursor_info d_info;
+
+#ifdef CONFIG_REISER4_BADBLOCKS
+       /* Alternative master superblock offset (in bytes) */
+       unsigned long altsuper;
+#endif
+       struct repacker *repacker;
+       struct page *status_page;
+       struct bio *status_bio;
+
+#if REISER4_DEBUG
+       /*
+        * minimum used blocks value (includes super blocks, bitmap blocks and
+        * other fs reserved areas), depends on fs format and fs size.
+        */
+       __u64 min_blocks_used;
+
+       /*
+        * when debugging is on, all jnodes (including znodes, bitmaps, etc.)
+        * are kept on a list anchored at sbinfo->all_jnodes. This list is
+        * protected by sbinfo->all_guard spin lock. This lock should be taken
+        * with _irq modifier, because it is also modified from interrupt
+        * contexts (by RCU).
+        */
+       spinlock_t all_guard;
+       /* list of all jnodes */
+       struct list_head all_jnodes;
+#endif
+       struct dentry *debugfs_root;
+};
+
+extern reiser4_super_info_data *get_super_private_nocheck(const struct
+                                                         super_block *super);
+
+/* Return reiser4-specific part of super block */
+static inline reiser4_super_info_data *get_super_private(const struct
+                                                        super_block *super)
+{
+       assert("nikita-447", super != NULL);
+
+       return (reiser4_super_info_data *) super->s_fs_info;
+}
+
+/* get ent context for the @super */
+static inline entd_context *get_entd_context(struct super_block *super)
+{
+       return &get_super_private(super)->entd;
+}
+
+/* "Current" super-block: main super block used during current system
+   call. Reference to this super block is stored in reiser4_context. */
+static inline struct super_block *reiser4_get_current_sb(void)
+{
+       return get_current_context()->super;
+}
+
+/* Reiser4-specific part of "current" super-block: main super block used
+   during current system call. Reference to this super block is stored in
+   reiser4_context. */
+static inline reiser4_super_info_data *get_current_super_private(void)
+{
+       return get_super_private(reiser4_get_current_sb());
+}
+
+static inline ra_params_t *get_current_super_ra_params(void)
+{
+       return &(get_current_super_private()->ra_params);
+}
+
+/*
+ * true, if file system on @super is read-only
+ */
+static inline int rofs_super(struct super_block *super)
+{
+       return super->s_flags & MS_RDONLY;
+}
+
+/*
+ * true, if @tree represents read-only file system
+ */
+static inline int rofs_tree(reiser4_tree * tree)
+{
+       return rofs_super(tree->super);
+}
+
+/*
+ * true, if file system where @inode lives on, is read-only
+ */
+static inline int rofs_inode(struct inode *inode)
+{
+       return rofs_super(inode->i_sb);
+}
+
+/*
+ * true, if file system where @node lives on, is read-only
+ */
+static inline int rofs_jnode(jnode * node)
+{
+       return rofs_tree(jnode_get_tree(node));
+}
+
+extern __u64 reiser4_current_block_count(void);
+
+extern void build_object_ops(struct super_block *super, object_ops * ops);
+
+#define REISER4_SUPER_MAGIC 0x52345362 /* (*(__u32 *)"R4Sb"); */
+
+static inline void spin_lock_reiser4_super(reiser4_super_info_data *sbinfo)
+{
+       spin_lock(&(sbinfo->guard));
+}
+
+static inline void spin_unlock_reiser4_super(reiser4_super_info_data *sbinfo)
+{
+       assert_spin_locked(&(sbinfo->guard));
+       spin_unlock(&(sbinfo->guard));
+}
+
+extern __u64 reiser4_flush_reserved(const struct super_block *);
+extern int reiser4_is_set(const struct super_block *super, reiser4_fs_flag f);
+extern long reiser4_statfs_type(const struct super_block *super);
+extern __u64 reiser4_block_count(const struct super_block *super);
+extern void reiser4_set_block_count(const struct super_block *super, __u64 nr);
+extern __u64 reiser4_data_blocks(const struct super_block *super);
+extern void reiser4_set_data_blocks(const struct super_block *super, __u64 nr);
+extern __u64 reiser4_free_blocks(const struct super_block *super);
+extern void reiser4_set_free_blocks(const struct super_block *super, __u64 nr);
+extern __u32 reiser4_mkfs_id(const struct super_block *super);
+
+extern __u64 reiser4_free_committed_blocks(const struct super_block *super);
+
+extern __u64 reiser4_grabbed_blocks(const struct super_block *);
+extern __u64 reiser4_fake_allocated(const struct super_block *);
+extern __u64 reiser4_fake_allocated_unformatted(const struct super_block *);
+extern __u64 reiser4_clustered_blocks(const struct super_block *);
+
+extern long reiser4_reserved_blocks(const struct super_block *super, uid_t uid,
+                                   gid_t gid);
+
+extern reiser4_space_allocator *
+reiser4_get_space_allocator(const struct super_block *super);
+extern reiser4_oid_allocator *
+reiser4_get_oid_allocator(const struct super_block *super);
+extern struct inode *reiser4_get_super_fake(const struct super_block *super);
+extern struct inode *reiser4_get_cc_fake(const struct super_block *super);
+extern struct inode *reiser4_get_bitmap_fake(const struct super_block *super);
+extern reiser4_tree *reiser4_get_tree(const struct super_block *super);
+extern int is_reiser4_super(const struct super_block *super);
+
+extern int reiser4_blocknr_is_sane(const reiser4_block_nr * blk);
+extern int reiser4_blocknr_is_sane_for(const struct super_block *super,
+                                      const reiser4_block_nr * blk);
+extern int reiser4_fill_super(struct super_block *s, void *data, int silent);
+extern int reiser4_done_super(struct super_block *s);
+
+/* step of fill super */
+extern int reiser4_init_fs_info(struct super_block *);
+extern void reiser4_done_fs_info(struct super_block *);
+extern int reiser4_init_super_data(struct super_block *, char *opt_string);
+extern int reiser4_init_read_super(struct super_block *, int silent);
+extern int reiser4_init_root_inode(struct super_block *);
+extern reiser4_plugin *get_default_plugin(pset_member memb);
+
+/* Maximal possible object id. */
+#define  ABSOLUTE_MAX_OID ((oid_t)~0)
+
+#define OIDS_RESERVED  ( 1 << 16 )
+int oid_init_allocator(struct super_block *, oid_t nr_files, oid_t next);
+oid_t oid_allocate(struct super_block *);
+int oid_release(struct super_block *, oid_t);
+oid_t oid_next(const struct super_block *);
+void oid_count_allocated(void);
+void oid_count_released(void);
+long oids_used(const struct super_block *);
+
+#if REISER4_DEBUG
+void print_fs_info(const char *prefix, const struct super_block *);
+#endif
+
+extern void destroy_reiser4_cache(struct kmem_cache **);
+
+extern struct super_operations reiser4_super_operations;
+extern struct export_operations reiser4_export_operations;
+extern struct dentry_operations reiser4_dentry_operations;
+
+/* __REISER4_SUPER_H__ */
+#endif
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 120
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/super_ops.c linux-2.6.20/fs/reiser4/super_ops.c
--- linux-2.6.20.orig/fs/reiser4/super_ops.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/super_ops.c 2007-05-06 14:50:43.879031967 +0400
@@ -0,0 +1,728 @@
+/* Copyright 2005 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+#include "inode.h"
+#include "page_cache.h"
+#include "ktxnmgrd.h"
+#include "flush.h"
+#include "safe_link.h"
+
+#include <linux/vfs.h>
+#include <linux/writeback.h>
+#include <linux/mount.h>
+#include <linux/seq_file.h>
+#include <linux/debugfs.h>
+
+/* slab cache for inodes */
+static struct kmem_cache *inode_cache;
+
+static struct dentry *reiser4_debugfs_root = NULL;
+
+/**
+ * init_once - constructor for reiser4 inodes
+ * @obj: inode to be initialized
+ * @cache: cache @obj belongs to
+ * @flags: SLAB flags
+ *
+ * Initialization function to be called when new page is allocated by reiser4
+ * inode cache. It is set on inode cache creation.
+ */
+static void init_once(void *obj, struct kmem_cache *cache, unsigned long flags)
+{
+       reiser4_inode_object *info;
+
+       info = obj;
+
+       if ((flags & (SLAB_CTOR_VERIFY | SLAB_CTOR_CONSTRUCTOR)) ==
+           SLAB_CTOR_CONSTRUCTOR) {
+               /* initialize vfs inode */
+               inode_init_once(&info->vfs_inode);
+
+               /*
+                * initialize reiser4 specific part fo inode.
+                * NOTE-NIKITA add here initializations for locks, list heads,
+                * etc. that will be added to our private inode part.
+                */
+               INIT_LIST_HEAD(get_readdir_list(&info->vfs_inode));
+               init_rwsem(&info->p.conv_sem);
+               /* init semaphore which is used during inode loading */
+               loading_init_once(&info->p);
+               INIT_RADIX_TREE(jnode_tree_by_reiser4_inode(&info->p),
+                               GFP_ATOMIC);
+#if REISER4_DEBUG
+               info->p.nr_jnodes = 0;
+#endif
+       }
+}
+
+/**
+ * init_inodes - create znode cache
+ *
+ * Initializes slab cache of inodes. It is part of reiser4 module initialization.
+ */
+static int init_inodes(void)
+{
+       inode_cache = kmem_cache_create("reiser4_inode",
+                                       sizeof(reiser4_inode_object),
+                                       0,
+                                       SLAB_HWCACHE_ALIGN |
+                                       SLAB_RECLAIM_ACCOUNT, init_once, NULL);
+       if (inode_cache == NULL)
+               return RETERR(-ENOMEM);
+       return 0;
+}
+
+/**
+ * done_inodes - delete inode cache
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+static void done_inodes(void)
+{
+       destroy_reiser4_cache(&inode_cache);
+}
+
+/**
+ * reiser4_alloc_inode - alloc_inode of super operations
+ * @super: super block new inode is allocated for
+ *
+ * Allocates new inode, initializes reiser4 specific part of it.
+ */
+static struct inode *reiser4_alloc_inode(struct super_block *super)
+{
+       reiser4_inode_object *obj;
+
+       assert("nikita-1696", super != NULL);
+       obj = kmem_cache_alloc(inode_cache, reiser4_ctx_gfp_mask_get());
+       if (obj != NULL) {
+               reiser4_inode *info;
+
+               info = &obj->p;
+
+               info->pset = plugin_set_get_empty();
+               info->hset = plugin_set_get_empty();
+               info->extmask = 0;
+               info->locality_id = 0ull;
+               info->plugin_mask = 0;
+               info->heir_mask = 0;
+#if !REISER4_INO_IS_OID
+               info->oid_hi = 0;
+#endif
+               reiser4_seal_init(&info->sd_seal, NULL, NULL);
+               coord_init_invalid(&info->sd_coord, NULL);
+               info->flags = 0;
+               spin_lock_init(&info->guard);
+               /* this deals with info's loading semaphore */
+               loading_alloc(info);
+               info->vroot = UBER_TREE_ADDR;
+               return &obj->vfs_inode;
+       } else
+               return NULL;
+}
+
+/**
+ * reiser4_destroy_inode - destroy_inode of super operations
+ * @inode: inode being destroyed
+ *
+ * Puts reiser4 specific portion of inode, frees memory occupied by inode.
+ */
+static void reiser4_destroy_inode(struct inode *inode)
+{
+       reiser4_inode *info;
+
+       info = reiser4_inode_data(inode);
+
+       assert("vs-1220", inode_has_no_jnodes(info));
+
+       if (!is_bad_inode(inode) && is_inode_loaded(inode)) {
+               file_plugin *fplug = inode_file_plugin(inode);
+               if (fplug->destroy_inode != NULL)
+                       fplug->destroy_inode(inode);
+       }
+       reiser4_dispose_cursors(inode);
+       if (info->pset)
+               plugin_set_put(info->pset);
+       if (info->hset)
+               plugin_set_put(info->hset);
+
+       /*
+        * cannot add similar assertion about ->i_list as prune_icache return
+        * inode into slab with dangling ->list.{next,prev}. This is safe,
+        * because they are re-initialized in the new_inode().
+        */
+       assert("nikita-2895", list_empty(&inode->i_dentry));
+       assert("nikita-2896", hlist_unhashed(&inode->i_hash));
+       assert("nikita-2898", list_empty_careful(get_readdir_list(inode)));
+
+       /* this deals with info's loading semaphore */
+       loading_destroy(info);
+
+       kmem_cache_free(inode_cache,
+                       container_of(info, reiser4_inode_object, p));
+}
+
+/**
+ * reiser4_dirty_inode - dirty_inode of super operations
+ * @inode: inode being dirtied
+ *
+ * Updates stat data.
+ */
+static void reiser4_dirty_inode(struct inode *inode)
+{
+       int result;
+
+       if (!is_in_reiser4_context())
+               return;
+       assert("", !IS_RDONLY(inode));
+       assert("", (inode_file_plugin(inode)->estimate.update(inode) <=
+                   get_current_context()->grabbed_blocks));
+
+       result = reiser4_update_sd(inode);
+       if (result)
+               warning("", "failed to dirty inode for %llu: %d",
+                       get_inode_oid(inode), result);
+}
+
+/**
+ * reiser4_delete_inode - delete_inode of super operations
+ * @inode: inode to delete
+ *
+ * Calls file plugin's delete_object method to delete object items from
+ * filesystem tree and calls clear_inode.
+ */
+static void reiser4_delete_inode(struct inode *inode)
+{
+       reiser4_context *ctx;
+       file_plugin *fplug;
+
+       ctx = reiser4_init_context(inode->i_sb);
+       if (IS_ERR(ctx)) {
+               warning("vs-15", "failed to init context");
+               return;
+       }
+
+       if (is_inode_loaded(inode)) {
+               fplug = inode_file_plugin(inode);
+               if (fplug != NULL && fplug->delete_object != NULL)
+                       fplug->delete_object(inode);
+       }
+
+       truncate_inode_pages(&inode->i_data, 0);
+       inode->i_blocks = 0;
+       clear_inode(inode);
+       reiser4_exit_context(ctx);
+}
+
+/**
+ * reiser4_put_super - put_super of super operations
+ * @super: super block to free
+ *
+ * Stops daemons, release resources, umounts in short.
+ */
+static void reiser4_put_super(struct super_block *super)
+{
+       reiser4_super_info_data *sbinfo;
+       reiser4_context *ctx;
+
+       sbinfo = get_super_private(super);
+       assert("vs-1699", sbinfo);
+
+       debugfs_remove(sbinfo->tmgr.debugfs_atom_count);
+       debugfs_remove(sbinfo->tmgr.debugfs_id_count);
+       debugfs_remove(sbinfo->debugfs_root);
+
+       ctx = reiser4_init_context(super);
+       if (IS_ERR(ctx)) {
+               warning("vs-17", "failed to init context");
+               return;
+       }
+
+       /* have disk format plugin to free its resources */
+       if (get_super_private(super)->df_plug->release)
+               get_super_private(super)->df_plug->release(super);
+
+       reiser4_done_formatted_fake(super);
+
+       /* stop daemons: ktxnmgr and entd */
+       reiser4_done_entd(super);
+       reiser4_done_ktxnmgrd(super);
+       reiser4_done_txnmgr(&sbinfo->tmgr);
+
+       reiser4_done_fs_info(super);
+       reiser4_exit_context(ctx);
+}
+
+/**
+ * reiser4_write_super - write_super of super operations
+ * @super: super block to write
+ *
+ * Captures znode associated with super block, comit all transactions.
+ */
+static void reiser4_write_super(struct super_block *super)
+{
+       int ret;
+       reiser4_context *ctx;
+
+       assert("vs-1700", !rofs_super(super));
+
+       ctx = reiser4_init_context(super);
+       if (IS_ERR(ctx)) {
+               warning("vs-16", "failed to init context");
+               return;
+       }
+
+       ret = reiser4_capture_super_block(super);
+       if (ret != 0)
+               warning("vs-1701",
+                       "reiser4_capture_super_block failed in write_super: %d",
+                       ret);
+       ret = txnmgr_force_commit_all(super, 0);
+       if (ret != 0)
+               warning("jmacd-77113",
+                       "txn_force failed in write_super: %d", ret);
+
+       super->s_dirt = 0;
+
+       reiser4_exit_context(ctx);
+}
+
+/**
+ * reiser4_statfs - statfs of super operations
+ * @super: super block of file system in queried
+ * @stafs: buffer to fill with statistics
+ *
+ * Returns information about filesystem.
+ */
+static int reiser4_statfs(struct dentry *dentry, struct kstatfs *statfs)
+{
+       sector_t total;
+       sector_t reserved;
+       sector_t free;
+       sector_t forroot;
+       sector_t deleted;
+       reiser4_context *ctx;
+       struct super_block *super = dentry->d_sb;
+
+       assert("nikita-408", super != NULL);
+       assert("nikita-409", statfs != NULL);
+
+       ctx = reiser4_init_context(super);
+       if (IS_ERR(ctx))
+               return PTR_ERR(ctx);
+
+       statfs->f_type = reiser4_statfs_type(super);
+       statfs->f_bsize = super->s_blocksize;
+
+       /*
+        * 5% of total block space is reserved. This is needed for flush and
+        * for truncates (so that we are able to perform truncate/unlink even
+        * on the otherwise completely full file system). If this reservation
+        * is hidden from statfs(2), users will mistakenly guess that they
+        * have enough free space to complete some operation, which is
+        * frustrating.
+        *
+        * Another possible solution is to subtract ->blocks_reserved from
+        * ->f_bfree, but changing available space seems less intrusive than
+        * letting user to see 5% of disk space to be used directly after
+        * mkfs.
+        */
+       total = reiser4_block_count(super);
+       reserved = get_super_private(super)->blocks_reserved;
+       deleted = txnmgr_count_deleted_blocks();
+       free = reiser4_free_blocks(super) + deleted;
+       forroot = reiser4_reserved_blocks(super, 0, 0);
+
+       /*
+        * These counters may be in inconsistent state because we take the
+        * values without keeping any global spinlock.  Here we do a sanity
+        * check that free block counter does not exceed the number of all
+        * blocks.
+        */
+       if (free > total)
+               free = total;
+       statfs->f_blocks = total - reserved;
+       /* make sure statfs->f_bfree is never larger than statfs->f_blocks */
+       if (free > reserved)
+               free -= reserved;
+       else
+               free = 0;
+       statfs->f_bfree = free;
+
+       if (free > forroot)
+               free -= forroot;
+       else
+               free = 0;
+       statfs->f_bavail = free;
+
+       statfs->f_files = 0;
+       statfs->f_ffree = 0;
+
+       /* maximal acceptable name length depends on directory plugin. */
+       assert("nikita-3351", super->s_root->d_inode != NULL);
+       statfs->f_namelen = reiser4_max_filename_len(super->s_root->d_inode);
+       reiser4_exit_context(ctx);
+       return 0;
+}
+
+/**
+ * reiser4_clear_inode - clear_inode of super operation
+ * @inode: inode about to destroy
+ *
+ * Does sanity checks: being destroyed should have all jnodes detached.
+ */
+static void reiser4_clear_inode(struct inode *inode)
+{
+#if REISER4_DEBUG
+       reiser4_inode *r4_inode;
+
+       r4_inode = reiser4_inode_data(inode);
+       if (!inode_has_no_jnodes(r4_inode))
+               warning("vs-1732", "reiser4 inode has %ld jnodes\n",
+                       r4_inode->nr_jnodes);
+#endif
+}
+
+/**
+ * reiser4_sync_inodes - sync_inodes of super operations
+ * @super:
+ * @wbc:
+ *
+ * This method is called by background and non-backgound writeback. Reiser4's
+ * implementation uses generic_sync_sb_inodes to call reiser4_writepages for
+ * each of dirty inodes. Reiser4_writepages handles pages dirtied via shared
+ * mapping - dirty pages get into atoms. Writeout is called to flush some
+ * atoms.
+ */
+static void reiser4_sync_inodes(struct super_block *super,
+                               struct writeback_control *wbc)
+{
+       reiser4_context *ctx;
+       long to_write;
+
+       if (wbc->for_kupdate)
+               /* reiser4 has its own means of periodical write-out */
+               return;
+
+       to_write = wbc->nr_to_write;
+       assert("vs-49", wbc->older_than_this == NULL);
+
+       ctx = reiser4_init_context(super);
+       if (IS_ERR(ctx)) {
+               warning("vs-13", "failed to init context");
+               return;
+       }
+
+       /*
+        * call reiser4_writepages for each of dirty inodes to turn dirty pages
+        * into transactions if they were not yet.
+        */
+       generic_sync_sb_inodes(super, wbc);
+
+       /* flush goes here */
+       wbc->nr_to_write = to_write;
+       reiser4_writeout(super, wbc);
+
+       /* avoid recursive calls to ->sync_inodes */
+       context_set_commit_async(ctx);
+       reiser4_exit_context(ctx);
+}
+
+/**
+ * reiser4_show_options - show_options of super operations
+ * @m: file where to write information
+ * @mnt: mount structure
+ *
+ * Makes reiser4 mount options visible in /proc/mounts.
+ */
+static int reiser4_show_options(struct seq_file *m, struct vfsmount *mnt)
+{
+       struct super_block *super;
+       reiser4_super_info_data *sbinfo;
+
+       super = mnt->mnt_sb;
+       sbinfo = get_super_private(super);
+
+       seq_printf(m, ",atom_max_size=0x%x", sbinfo->tmgr.atom_max_size);
+       seq_printf(m, ",atom_max_age=0x%x", sbinfo->tmgr.atom_max_age);
+       seq_printf(m, ",atom_min_size=0x%x", sbinfo->tmgr.atom_min_size);
+       seq_printf(m, ",atom_max_flushers=0x%x",
+                  sbinfo->tmgr.atom_max_flushers);
+       seq_printf(m, ",cbk_cache_slots=0x%x",
+                  sbinfo->tree.cbk_cache.nr_slots);
+
+       return 0;
+}
+
+struct super_operations reiser4_super_operations = {
+       .alloc_inode = reiser4_alloc_inode,
+       .destroy_inode = reiser4_destroy_inode,
+       .dirty_inode = reiser4_dirty_inode,
+       .delete_inode = reiser4_delete_inode,
+       .put_super = reiser4_put_super,
+       .write_super = reiser4_write_super,
+       .statfs = reiser4_statfs,
+       .clear_inode = reiser4_clear_inode,
+       .sync_inodes = reiser4_sync_inodes,
+       .show_options = reiser4_show_options
+};
+
+/**
+ * fill_super - initialize super block on mount
+ * @super: super block to fill
+ * @data: reiser4 specific mount option
+ * @silent:
+ *
+ * This is to be called by reiser4_get_sb. Mounts filesystem.
+ */
+static int fill_super(struct super_block *super, void *data, int silent)
+{
+       reiser4_context ctx;
+       int result;
+       reiser4_super_info_data *sbinfo;
+
+       assert("zam-989", super != NULL);
+
+       super->s_op = NULL;
+       init_stack_context(&ctx, super);
+
+       /* allocate reiser4 specific super block */
+       if ((result = reiser4_init_fs_info(super)) != 0)
+               goto failed_init_sinfo;
+
+       sbinfo = get_super_private(super);
+       /* initialize various reiser4 parameters, parse mount options */
+       if ((result = reiser4_init_super_data(super, data)) != 0)
+               goto failed_init_super_data;
+
+       /* read reiser4 master super block, initialize disk format plugin */
+       if ((result = reiser4_init_read_super(super, silent)) != 0)
+               goto failed_init_read_super;
+
+       /* initialize transaction manager */
+       reiser4_init_txnmgr(&sbinfo->tmgr);
+
+       /* initialize ktxnmgrd context and start kernel thread ktxnmrgd */
+       if ((result = reiser4_init_ktxnmgrd(super)) != 0)
+               goto failed_init_ktxnmgrd;
+
+       /* initialize entd context and start kernel thread entd */
+       if ((result = reiser4_init_entd(super)) != 0)
+               goto failed_init_entd;
+
+       /* initialize address spaces for formatted nodes and bitmaps */
+       if ((result = reiser4_init_formatted_fake(super)) != 0)
+               goto failed_init_formatted_fake;
+
+       /* initialize disk format plugin */
+       if ((result = get_super_private(super)->df_plug->init_format(super, data)) != 0 )
+               goto failed_init_disk_format;
+
+       /*
+        * There are some 'committed' versions of reiser4 super block counters,
+        * which correspond to reiser4 on-disk state. These counters are
+        * initialized here
+        */
+       sbinfo->blocks_free_committed = sbinfo->blocks_free;
+       sbinfo->nr_files_committed = oids_used(super);
+
+       /* get inode of root directory */
+       if ((result = reiser4_init_root_inode(super)) != 0)
+               goto failed_init_root_inode;
+
+       if ((result = get_super_private(super)->df_plug->version_update(super)) != 0 )
+               goto failed_update_format_version;
+
+       process_safelinks(super);
+       reiser4_exit_context(&ctx);
+
+       sbinfo->debugfs_root = debugfs_create_dir(super->s_id,
+                                                 reiser4_debugfs_root);
+       if (sbinfo->debugfs_root) {
+               sbinfo->tmgr.debugfs_atom_count =
+                       debugfs_create_u32("atom_count", S_IFREG|S_IRUSR,
+                                          sbinfo->debugfs_root,
+                                          &sbinfo->tmgr.atom_count);
+               sbinfo->tmgr.debugfs_id_count =
+                       debugfs_create_u32("id_count", S_IFREG|S_IRUSR,
+                                          sbinfo->debugfs_root,
+                                          &sbinfo->tmgr.id_count);
+       }
+       return 0;
+
+ failed_update_format_version:
+ failed_init_root_inode:
+       if (sbinfo->df_plug->release)
+               sbinfo->df_plug->release(super);
+ failed_init_disk_format:
+       reiser4_done_formatted_fake(super);
+ failed_init_formatted_fake:
+       reiser4_done_entd(super);
+ failed_init_entd:
+       reiser4_done_ktxnmgrd(super);
+ failed_init_ktxnmgrd:
+       reiser4_done_txnmgr(&sbinfo->tmgr);
+ failed_init_read_super:
+ failed_init_super_data:
+       reiser4_done_fs_info(super);
+ failed_init_sinfo:
+       reiser4_exit_context(&ctx);
+       return result;
+}
+
+/**
+ * reiser4_get_sb - get_sb of file_system_type operations
+ * @fs_type:
+ * @flags: mount flags MS_RDONLY, MS_VERBOSE, etc
+ * @dev_name: block device file name
+ * @data: specific mount options
+ *
+ * Reiser4 mount entry.
+ */
+static int reiser4_get_sb(struct file_system_type *fs_type, int flags,
+                       const char *dev_name, void *data, struct vfsmount *mnt)
+{
+       return get_sb_bdev(fs_type, flags, dev_name, data, fill_super, mnt);
+}
+
+/* structure describing the reiser4 filesystem implementation */
+static struct file_system_type reiser4_fs_type = {
+       .owner = THIS_MODULE,
+       .name = "reiser4",
+       .fs_flags = FS_REQUIRES_DEV,
+       .get_sb = reiser4_get_sb,
+       .kill_sb = kill_block_super,
+       .next = NULL
+};
+
+void destroy_reiser4_cache(struct kmem_cache **cachep)
+{
+       BUG_ON(*cachep == NULL);
+       kmem_cache_destroy(*cachep);
+       *cachep = NULL;
+}
+
+/**
+ * init_reiser4 - reiser4 initialization entry point
+ *
+ * Initializes reiser4 slabs, registers reiser4 filesystem type. It is called
+ * on kernel initialization or during reiser4 module load.
+ */
+static int __init init_reiser4(void)
+{
+       int result;
+
+       printk(KERN_INFO
+              "Loading Reiser4. "
+              "See www.namesys.com for a description of Reiser4.\n");
+
+       /* initialize slab cache of inodes */
+       if ((result = init_inodes()) != 0)
+               goto failed_inode_cache;
+
+       /* initialize cache of znodes */
+       if ((result = init_znodes()) != 0)
+               goto failed_init_znodes;
+
+       /* initialize all plugins */
+       if ((result = init_plugins()) != 0)
+               goto failed_init_plugins;
+
+       /* initialize cache of plugin_set-s and plugin_set's hash table */
+       if ((result = init_plugin_set()) != 0)
+               goto failed_init_plugin_set;
+
+       /* initialize caches of txn_atom-s and txn_handle-s */
+       if ((result = init_txnmgr_static()) != 0)
+               goto failed_init_txnmgr_static;
+
+       /* initialize cache of jnodes */
+       if ((result = init_jnodes()) != 0)
+               goto failed_init_jnodes;
+
+       /* initialize cache of flush queues */
+       if ((result = reiser4_init_fqs()) != 0)
+               goto failed_init_fqs;
+
+       /* initialize cache of structures attached to dentry->d_fsdata */
+       if ((result = reiser4_init_dentry_fsdata()) != 0)
+               goto failed_init_dentry_fsdata;
+
+       /* initialize cache of structures attached to file->private_data */
+       if ((result = reiser4_init_file_fsdata()) != 0)
+               goto failed_init_file_fsdata;
+
+       /*
+        * initialize cache of d_cursors. See plugin/file_ops_readdir.c for
+        * more details
+        */
+       if ((result = reiser4_init_d_cursor()) != 0)
+               goto failed_init_d_cursor;
+
+       if ((result = register_filesystem(&reiser4_fs_type)) == 0) {
+               reiser4_debugfs_root = debugfs_create_dir("reiser4", NULL);
+               return 0;
+       }
+
+       reiser4_done_d_cursor();
+ failed_init_d_cursor:
+       reiser4_done_file_fsdata();
+ failed_init_file_fsdata:
+       reiser4_done_dentry_fsdata();
+ failed_init_dentry_fsdata:
+       reiser4_done_fqs();
+ failed_init_fqs:
+       done_jnodes();
+ failed_init_jnodes:
+       done_txnmgr_static();
+ failed_init_txnmgr_static:
+       done_plugin_set();
+ failed_init_plugin_set:
+ failed_init_plugins:
+       done_znodes();
+ failed_init_znodes:
+       done_inodes();
+ failed_inode_cache:
+       return result;
+}
+
+/**
+ * done_reiser4 - reiser4 exit entry point
+ *
+ * Unregister reiser4 filesystem type, deletes caches. It is called on shutdown
+ * or at module unload.
+ */
+static void __exit done_reiser4(void)
+{
+       int result;
+
+       debugfs_remove(reiser4_debugfs_root);
+       result = unregister_filesystem(&reiser4_fs_type);
+       BUG_ON(result != 0);
+       reiser4_done_d_cursor();
+       reiser4_done_file_fsdata();
+       reiser4_done_dentry_fsdata();
+       reiser4_done_fqs();
+       done_jnodes();
+       done_txnmgr_static();
+       done_plugin_set();
+       done_znodes();
+       destroy_reiser4_cache(&inode_cache);
+}
+
+module_init(init_reiser4);
+module_exit(done_reiser4);
+
+MODULE_DESCRIPTION("Reiser4 filesystem");
+MODULE_AUTHOR("Hans Reiser <Reiser@Namesys.COM>");
+
+MODULE_LICENSE("GPL");
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/tap.c linux-2.6.20/fs/reiser4/tap.c
--- linux-2.6.20.orig/fs/reiser4/tap.c  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tap.c       2007-05-06 14:50:43.879031967 +0400
@@ -0,0 +1,377 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/*
+   Tree Access Pointer (tap).
+
+   tap is data structure combining coord and lock handle (mostly). It is
+   useful when one has to scan tree nodes (for example, in readdir, or flush),
+   for tap functions allow to move tap in either direction transparently
+   crossing unit/item/node borders.
+
+   Tap doesn't provide automatic synchronization of its fields as it is
+   supposed to be per-thread object.
+*/
+
+#include "forward.h"
+#include "debug.h"
+#include "coord.h"
+#include "tree.h"
+#include "context.h"
+#include "tap.h"
+#include "znode.h"
+#include "tree_walk.h"
+
+#if REISER4_DEBUG
+static int tap_invariant(const tap_t * tap);
+static void tap_check(const tap_t * tap);
+#else
+#define tap_check(tap) noop
+#endif
+
+/** load node tap is pointing to, if not loaded already */
+int reiser4_tap_load(tap_t * tap)
+{
+       tap_check(tap);
+       if (tap->loaded == 0) {
+               int result;
+
+               result = zload_ra(tap->coord->node, &tap->ra_info);
+               if (result != 0)
+                       return result;
+               coord_clear_iplug(tap->coord);
+       }
+       ++tap->loaded;
+       tap_check(tap);
+       return 0;
+}
+
+/** release node tap is pointing to. Dual to tap_load() */
+void reiser4_tap_relse(tap_t * tap)
+{
+       tap_check(tap);
+       if (tap->loaded > 0) {
+               --tap->loaded;
+               if (tap->loaded == 0) {
+                       zrelse(tap->coord->node);
+               }
+       }
+       tap_check(tap);
+}
+
+/**
+ * init tap to consist of @coord and @lh. Locks on nodes will be acquired with
+ * @mode
+ */
+void reiser4_tap_init(tap_t * tap, coord_t * coord, lock_handle * lh,
+                     znode_lock_mode mode)
+{
+       tap->coord = coord;
+       tap->lh = lh;
+       tap->mode = mode;
+       tap->loaded = 0;
+       INIT_LIST_HEAD(&tap->linkage);
+       reiser4_init_ra_info(&tap->ra_info);
+}
+
+/** add @tap to the per-thread list of all taps */
+void reiser4_tap_monitor(tap_t * tap)
+{
+       assert("nikita-2623", tap != NULL);
+       tap_check(tap);
+       list_add(&tap->linkage, reiser4_taps_list());
+       tap_check(tap);
+}
+
+/* duplicate @src into @dst. Copy lock handle. @dst is not initially
+ * loaded. */
+void reiser4_tap_copy(tap_t * dst, tap_t * src)
+{
+       assert("nikita-3193", src != NULL);
+       assert("nikita-3194", dst != NULL);
+
+       *dst->coord = *src->coord;
+       if (src->lh->node)
+               copy_lh(dst->lh, src->lh);
+       dst->mode = src->mode;
+       dst->loaded = 0;
+       INIT_LIST_HEAD(&dst->linkage);
+       dst->ra_info = src->ra_info;
+}
+
+/** finish with @tap */
+void reiser4_tap_done(tap_t * tap)
+{
+       assert("nikita-2565", tap != NULL);
+       tap_check(tap);
+       if (tap->loaded > 0)
+               zrelse(tap->coord->node);
+       done_lh(tap->lh);
+       tap->loaded = 0;
+       list_del_init(&tap->linkage);
+       tap->coord->node = NULL;
+}
+
+/**
+ * move @tap to the new node, locked with @target. Load @target, if @tap was
+ * already loaded.
+ */
+int reiser4_tap_move(tap_t * tap, lock_handle * target)
+{
+       int result = 0;
+
+       assert("nikita-2567", tap != NULL);
+       assert("nikita-2568", target != NULL);
+       assert("nikita-2570", target->node != NULL);
+       assert("nikita-2569", tap->coord->node == tap->lh->node);
+
+       tap_check(tap);
+       if (tap->loaded > 0)
+               result = zload_ra(target->node, &tap->ra_info);
+
+       if (result == 0) {
+               if (tap->loaded > 0)
+                       zrelse(tap->coord->node);
+               done_lh(tap->lh);
+               copy_lh(tap->lh, target);
+               tap->coord->node = target->node;
+               coord_clear_iplug(tap->coord);
+       }
+       tap_check(tap);
+       return result;
+}
+
+/**
+ * move @tap to @target. Acquire lock on @target, if @tap was already
+ * loaded.
+ */
+static int tap_to(tap_t * tap, znode * target)
+{
+       int result;
+
+       assert("nikita-2624", tap != NULL);
+       assert("nikita-2625", target != NULL);
+
+       tap_check(tap);
+       result = 0;
+       if (tap->coord->node != target) {
+               lock_handle here;
+
+               init_lh(&here);
+               result = longterm_lock_znode(&here, target,
+                                            tap->mode, ZNODE_LOCK_HIPRI);
+               if (result == 0) {
+                       result = reiser4_tap_move(tap, &here);
+                       done_lh(&here);
+               }
+       }
+       tap_check(tap);
+       return result;
+}
+
+/**
+ * move @tap to given @target, loading and locking @target->node if
+ * necessary
+ */
+int tap_to_coord(tap_t * tap, coord_t * target)
+{
+       int result;
+
+       tap_check(tap);
+       result = tap_to(tap, target->node);
+       if (result == 0)
+               coord_dup(tap->coord, target);
+       tap_check(tap);
+       return result;
+}
+
+/** return list of all taps */
+struct list_head *reiser4_taps_list(void)
+{
+       return &get_current_context()->taps;
+}
+
+/** helper function for go_{next,prev}_{item,unit,node}() */
+int go_dir_el(tap_t * tap, sideof dir, int units_p)
+{
+       coord_t dup;
+       coord_t *coord;
+       int result;
+
+       int (*coord_dir) (coord_t *);
+       int (*get_dir_neighbor) (lock_handle *, znode *, int, int);
+       void (*coord_init) (coord_t *, const znode *);
+       ON_DEBUG(int (*coord_check) (const coord_t *));
+
+       assert("nikita-2556", tap != NULL);
+       assert("nikita-2557", tap->coord != NULL);
+       assert("nikita-2558", tap->lh != NULL);
+       assert("nikita-2559", tap->coord->node != NULL);
+
+       tap_check(tap);
+       if (dir == LEFT_SIDE) {
+               coord_dir = units_p ? coord_prev_unit : coord_prev_item;
+               get_dir_neighbor = reiser4_get_left_neighbor;
+               coord_init = coord_init_last_unit;
+       } else {
+               coord_dir = units_p ? coord_next_unit : coord_next_item;
+               get_dir_neighbor = reiser4_get_right_neighbor;
+               coord_init = coord_init_first_unit;
+       }
+       ON_DEBUG(coord_check =
+                units_p ? coord_is_existing_unit : coord_is_existing_item);
+       assert("nikita-2560", coord_check(tap->coord));
+
+       coord = tap->coord;
+       coord_dup(&dup, coord);
+       if (coord_dir(&dup) != 0) {
+               do {
+                       /* move to the left neighboring node */
+                       lock_handle dup;
+
+                       init_lh(&dup);
+                       result =
+                           get_dir_neighbor(&dup, coord->node, (int)tap->mode,
+                                            GN_CAN_USE_UPPER_LEVELS);
+                       if (result == 0) {
+                               result = reiser4_tap_move(tap, &dup);
+                               if (result == 0)
+                                       coord_init(tap->coord, dup.node);
+                               done_lh(&dup);
+                       }
+                       /* skip empty nodes */
+               } while ((result == 0) && node_is_empty(coord->node));
+       } else {
+               result = 0;
+               coord_dup(coord, &dup);
+       }
+       assert("nikita-2564", ergo(!result, coord_check(tap->coord)));
+       tap_check(tap);
+       return result;
+}
+
+/**
+ * move @tap to the next unit, transparently crossing item and node
+ * boundaries
+ */
+int go_next_unit(tap_t * tap)
+{
+       return go_dir_el(tap, RIGHT_SIDE, 1);
+}
+
+/**
+ * move @tap to the previous unit, transparently crossing item and node
+ * boundaries
+ */
+int go_prev_unit(tap_t * tap)
+{
+       return go_dir_el(tap, LEFT_SIDE, 1);
+}
+
+/**
+ * @shift times apply @actor to the @tap. This is used to move @tap by
+ * @shift units (or items, or nodes) in either direction.
+ */
+static int rewind_to(tap_t * tap, go_actor_t actor, int shift)
+{
+       int result;
+
+       assert("nikita-2555", shift >= 0);
+       assert("nikita-2562", tap->coord->node == tap->lh->node);
+
+       tap_check(tap);
+       result = reiser4_tap_load(tap);
+       if (result != 0)
+               return result;
+
+       for (; shift > 0; --shift) {
+               result = actor(tap);
+               assert("nikita-2563", tap->coord->node == tap->lh->node);
+               if (result != 0)
+                       break;
+       }
+       reiser4_tap_relse(tap);
+       tap_check(tap);
+       return result;
+}
+
+/** move @tap @shift units rightward */
+int rewind_right(tap_t * tap, int shift)
+{
+       return rewind_to(tap, go_next_unit, shift);
+}
+
+/** move @tap @shift units leftward */
+int rewind_left(tap_t * tap, int shift)
+{
+       return rewind_to(tap, go_prev_unit, shift);
+}
+
+#if REISER4_DEBUG
+/** debugging function: print @tap content in human readable form */
+static void print_tap(const char *prefix, const tap_t * tap)
+{
+       if (tap == NULL) {
+               printk("%s: null tap\n", prefix);
+               return;
+       }
+       printk("%s: loaded: %i, in-list: %i, node: %p, mode: %s\n", prefix,
+              tap->loaded, (&tap->linkage == tap->linkage.next &&
+                            &tap->linkage == tap->linkage.prev),
+              tap->lh->node,
+              lock_mode_name(tap->mode));
+       print_coord("\tcoord", tap->coord, 0);
+}
+
+/** check [tap-sane] invariant */
+static int tap_invariant(const tap_t * tap)
+{
+       /* [tap-sane] invariant */
+
+       if (tap == NULL)
+               return 1;
+       /* tap->mode is one of
+        *
+        * {ZNODE_NO_LOCK, ZNODE_READ_LOCK, ZNODE_WRITE_LOCK}, and
+        */
+       if (tap->mode != ZNODE_NO_LOCK &&
+           tap->mode != ZNODE_READ_LOCK && tap->mode != ZNODE_WRITE_LOCK)
+               return 2;
+       /* tap->coord != NULL, and */
+       if (tap->coord == NULL)
+               return 3;
+       /* tap->lh != NULL, and */
+       if (tap->lh == NULL)
+               return 4;
+       /* tap->loaded > 0 => znode_is_loaded(tap->coord->node), and */
+       if (!ergo(tap->loaded, znode_is_loaded(tap->coord->node)))
+               return 5;
+       /* tap->coord->node == tap->lh->node if tap->lh->node is not 0 */
+       if (tap->lh->node != NULL && tap->coord->node != tap->lh->node)
+               return 6;
+       return 0;
+}
+
+/** debugging function: check internal @tap consistency */
+static void tap_check(const tap_t * tap)
+{
+       int result;
+
+       result = tap_invariant(tap);
+       if (result != 0) {
+               print_tap("broken", tap);
+               reiser4_panic("nikita-2831", "tap broken: %i\n", result);
+       }
+}
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tap.h linux-2.6.20/fs/reiser4/tap.h
--- linux-2.6.20.orig/fs/reiser4/tap.h  1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tap.h       2007-05-06 14:50:43.879031967 +0400
@@ -0,0 +1,70 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* Tree Access Pointers. See tap.c for more details. */
+
+#if !defined( __REISER4_TAP_H__ )
+#define __REISER4_TAP_H__
+
+#include "forward.h"
+#include "readahead.h"
+
+/**
+    tree_access_pointer aka tap. Data structure combining coord_t and lock
+    handle.
+    Invariants involving this data-type, see doc/lock-ordering for details:
+
+      [tap-sane]
+ */
+struct tree_access_pointer {
+       /* coord tap is at */
+       coord_t *coord;
+       /* lock handle on ->coord->node */
+       lock_handle *lh;
+       /* mode of lock acquired by this tap */
+       znode_lock_mode mode;
+       /* incremented by reiser4_tap_load().
+          Decremented by reiser4_tap_relse(). */
+       int loaded;
+       /* list of taps */
+       struct list_head linkage;
+       /* read-ahead hint */
+       ra_info_t ra_info;
+};
+
+typedef int (*go_actor_t) (tap_t * tap);
+
+extern int reiser4_tap_load(tap_t * tap);
+extern void reiser4_tap_relse(tap_t * tap);
+extern void reiser4_tap_init(tap_t * tap, coord_t * coord, lock_handle * lh,
+                    znode_lock_mode mode);
+extern void reiser4_tap_monitor(tap_t * tap);
+extern void reiser4_tap_copy(tap_t * dst, tap_t * src);
+extern void reiser4_tap_done(tap_t * tap);
+extern int reiser4_tap_move(tap_t * tap, lock_handle * target);
+extern int tap_to_coord(tap_t * tap, coord_t * target);
+
+extern int go_dir_el(tap_t * tap, sideof dir, int units_p);
+extern int go_next_unit(tap_t * tap);
+extern int go_prev_unit(tap_t * tap);
+extern int rewind_right(tap_t * tap, int shift);
+extern int rewind_left(tap_t * tap, int shift);
+
+extern struct list_head *reiser4_taps_list(void);
+
+#define for_all_taps(tap)                                                     \
+       for (tap = list_entry(reiser4_taps_list()->next, tap_t, linkage);      \
+            reiser4_taps_list() != &tap->linkage;                             \
+            tap = list_entry(tap->linkage.next, tap_t, linkage))
+
+/* __REISER4_TAP_H__ */
+#endif
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree.c linux-2.6.20/fs/reiser4/tree.c
--- linux-2.6.20.orig/fs/reiser4/tree.c 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree.c      2007-05-06 14:50:43.883033217 +0400
@@ -0,0 +1,1876 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/*
+ * KEYS IN A TREE.
+ *
+ * The tree consists of nodes located on the disk. Node in the tree is either
+ * formatted or unformatted. Formatted node is one that has structure
+ * understood by the tree balancing and traversal code. Formatted nodes are
+ * further classified into leaf and internal nodes. Latter distinctions is
+ * (almost) of only historical importance: general structure of leaves and
+ * internal nodes is the same in Reiser4. Unformatted nodes contain raw data
+ * that are part of bodies of ordinary files and attributes.
+ *
+ * Each node in the tree spawns some interval in the key space. Key ranges for
+ * all nodes in the tree are disjoint. Actually, this only holds in some weak
+ * sense, because of the non-unique keys: intersection of key ranges for
+ * different nodes is either empty, or consists of exactly one key.
+ *
+ * Formatted node consists of a sequence of items. Each item spawns some
+ * interval in key space. Key ranges for all items in a tree are disjoint,
+ * modulo non-unique keys again. Items within nodes are ordered in the key
+ * order of the smallest key in a item.
+ *
+ * Particular type of item can be further split into units. Unit is piece of
+ * item that can be cut from item and moved into another item of the same
+ * time. Units are used by balancing code to repack data during balancing.
+ *
+ * Unit can be further split into smaller entities (for example, extent unit
+ * represents several pages, and it is natural for extent code to operate on
+ * particular pages and even bytes within one unit), but this is of no
+ * relevance to the generic balancing and lookup code.
+ *
+ * Although item is said to "spawn" range or interval of keys, it is not
+ * necessary that item contains piece of data addressable by each and every
+ * key in this range. For example, compound directory item, consisting of
+ * units corresponding to directory entries and keyed by hashes of file names,
+ * looks more as having "discrete spectrum": only some disjoint keys inside
+ * range occupied by this item really address data.
+ *
+ * No than less, each item always has well-defined least (minimal) key, that
+ * is recorded in item header, stored in the node this item is in. Also, item
+ * plugin can optionally define method ->max_key_inside() returning maximal
+ * key that can _possibly_ be located within this item. This method is used
+ * (mainly) to determine when given piece of data should be merged into
+ * existing item, in stead of creating new one. Because of this, even though
+ * ->max_key_inside() can be larger that any key actually located in the item,
+ * intervals
+ *
+ * [ reiser4_min_key( item ), ->max_key_inside( item ) ]
+ *
+ * are still disjoint for all items within the _same_ node.
+ *
+ * In memory node is represented by znode. It plays several roles:
+ *
+ *  . something locks are taken on
+ *
+ *  . something tracked by transaction manager (this is going to change)
+ *
+ *  . something used to access node data
+ *
+ *  . something used to maintain tree structure in memory: sibling and
+ *  parental linkage.
+ *
+ *  . something used to organize nodes into "slums"
+ *
+ * More on znodes see in znode.[ch]
+ *
+ * DELIMITING KEYS
+ *
+ *   To simplify balancing, allow some flexibility in locking and speed up
+ *   important coord cache optimization, we keep delimiting keys of nodes in
+ *   memory. Depending on disk format (implemented by appropriate node plugin)
+ *   node on disk can record both left and right delimiting key, only one of
+ *   them, or none. Still, our balancing and tree traversal code keep both
+ *   delimiting keys for a node that is in memory stored in the znode. When
+ *   node is first brought into memory during tree traversal, its left
+ *   delimiting key is taken from its parent, and its right delimiting key is
+ *   either next key in its parent, or is right delimiting key of parent if
+ *   node is the rightmost child of parent.
+ *
+ *   Physical consistency of delimiting key is protected by special dk
+ *   read-write lock. That is, delimiting keys can only be inspected or
+ *   modified under this lock. But dk lock is only sufficient for fast
+ *   "pessimistic" check, because to simplify code and to decrease lock
+ *   contention, balancing (carry) only updates delimiting keys right before
+ *   unlocking all locked nodes on the given tree level. For example,
+ *   coord-by-key cache scans LRU list of recently accessed znodes. For each
+ *   node it first does fast check under dk spin lock. If key looked for is
+ *   not between delimiting keys for this node, next node is inspected and so
+ *   on. If key is inside of the key range, long term lock is taken on node
+ *   and key range is rechecked.
+ *
+ * COORDINATES
+ *
+ *   To find something in the tree, you supply a key, and the key is resolved
+ *   by coord_by_key() into a coord (coordinate) that is valid as long as the
+ *   node the coord points to remains locked.  As mentioned above trees
+ *   consist of nodes that consist of items that consist of units. A unit is
+ *   the smallest and indivisible piece of tree as far as balancing and tree
+ *   search are concerned. Each node, item, and unit can be addressed by
+ *   giving its level in the tree and the key occupied by this entity.  A node
+ *   knows what the key ranges are of the items within it, and how to find its
+ *   items and invoke their item handlers, but it does not know how to access
+ *   individual units within its items except through the item handlers.
+ *   coord is a structure containing a pointer to the node, the ordinal number
+ *   of the item within this node (a sort of item offset), and the ordinal
+ *   number of the unit within this item.
+ *
+ * TREE LOOKUP
+ *
+ *   There are two types of access to the tree: lookup and modification.
+ *
+ *   Lookup is a search for the key in the tree. Search can look for either
+ *   exactly the key given to it, or for the largest key that is not greater
+ *   than the key given to it. This distinction is determined by "bias"
+ *   parameter of search routine (coord_by_key()). coord_by_key() either
+ *   returns error (key is not in the tree, or some kind of external error
+ *   occurred), or successfully resolves key into coord.
+ *
+ *   This resolution is done by traversing tree top-to-bottom from root level
+ *   to the desired level. On levels above twig level (level one above the
+ *   leaf level) nodes consist exclusively of internal items. Internal item is
+ *   nothing more than pointer to the tree node on the child level. On twig
+ *   level nodes consist of internal items intermixed with extent
+ *   items. Internal items form normal search tree structure used by traversal
+ *   to descent through the tree.
+ *
+ * TREE LOOKUP OPTIMIZATIONS
+ *
+ * Tree lookup described above is expensive even if all nodes traversed are
+ * already in the memory: for each node binary search within it has to be
+ * performed and binary searches are CPU consuming and tend to destroy CPU
+ * caches.
+ *
+ * Several optimizations are used to work around this:
+ *
+ *   . cbk_cache (look-aside cache for tree traversals, see search.c for
+ *   details)
+ *
+ *   . seals (see seal.[ch])
+ *
+ *   . vroot (see search.c)
+ *
+ * General search-by-key is layered thusly:
+ *
+ *                   [check seal, if any]   --ok--> done
+ *                           |
+ *                         failed
+ *                           |
+ *                           V
+ *                     [vroot defined] --no--> node = tree_root
+ *                           |                   |
+ *                          yes                  |
+ *                           |                   |
+ *                           V                   |
+ *                       node = vroot            |
+ *                                 |             |
+ *                                 |             |
+ *                                 |             |
+ *                                 V             V
+ *                            [check cbk_cache for key]  --ok--> done
+ *                                        |
+ *                                      failed
+ *                                        |
+ *                                        V
+ *                       [start tree traversal from node]
+ *
+ */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/item/static_stat.h"
+#include "plugin/item/item.h"
+#include "plugin/node/node.h"
+#include "plugin/plugin.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "carry.h"
+#include "carry_ops.h"
+#include "tap.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "page_cache.h"
+#include "super.h"
+#include "reiser4.h"
+#include "inode.h"
+
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/spinlock.h>
+
+/* Disk address (block number) never ever used for any real tree node. This is
+   used as block number of "uber" znode.
+
+   Invalid block addresses are 0 by tradition.
+
+*/
+const reiser4_block_nr UBER_TREE_ADDR = 0ull;
+
+#define CUT_TREE_MIN_ITERATIONS 64
+
+static int find_child_by_addr(znode * parent, znode * child, coord_t * result);
+
+/* return node plugin of coord->node */
+node_plugin *node_plugin_by_coord(const coord_t * coord)
+{
+       assert("vs-1", coord != NULL);
+       assert("vs-2", coord->node != NULL);
+
+       return coord->node->nplug;
+}
+
+/* insert item into tree. Fields of @coord are updated so that they can be
+ * used by consequent insert operation. */
+insert_result insert_by_key(reiser4_tree * tree        /* tree to insert new item
+                                                * into */ ,
+                           const reiser4_key * key /* key of new item */ ,
+                           reiser4_item_data * data    /* parameters for item
+                                                        * creation */ ,
+                           coord_t * coord /* resulting insertion coord */ ,
+                           lock_handle * lh    /* resulting lock
+                                                * handle */ ,
+                           tree_level stop_level /** level where to insert */ ,
+                           __u32 flags /* insertion flags */ )
+{
+       int result;
+
+       assert("nikita-358", tree != NULL);
+       assert("nikita-360", coord != NULL);
+
+       result = coord_by_key(tree, key, coord, lh, ZNODE_WRITE_LOCK,
+                             FIND_EXACT, stop_level, stop_level,
+                             flags | CBK_FOR_INSERT, NULL /*ra_info */ );
+       switch (result) {
+       default:
+               break;
+       case CBK_COORD_FOUND:
+               result = IBK_ALREADY_EXISTS;
+               break;
+       case CBK_COORD_NOTFOUND:
+               assert("nikita-2017", coord->node != NULL);
+               result = insert_by_coord(coord, data, key, lh, 0 /*flags */ );
+               break;
+       }
+       return result;
+}
+
+/* insert item by calling carry. Helper function called if short-cut
+   insertion failed  */
+static insert_result insert_with_carry_by_coord(coord_t * coord,       /* coord where to insert */
+                                               lock_handle * lh,       /* lock handle of insertion
+                                                                        * node */
+                                               reiser4_item_data * data,       /* parameters of new
+                                                                                * item */
+                                               const reiser4_key * key,        /* key of new item */
+                                               carry_opcode cop,       /* carry operation to perform */
+                                               cop_insert_flag flags
+                                               /* carry flags */ )
+{
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       carry_insert_data *cdata;
+       carry_op *op;
+
+       assert("umka-314", coord != NULL);
+
+       /* allocate carry_pool and 3 carry_level-s */
+       pool =
+           init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                           sizeof(*cdata));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+
+       op = reiser4_post_carry(lowest_level, cop, coord->node, 0);
+       if (IS_ERR(op) || (op == NULL)) {
+               done_carry_pool(pool);
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+       }
+       cdata = (carry_insert_data *) (lowest_level + 3);
+       cdata->coord = coord;
+       cdata->data = data;
+       cdata->key = key;
+       op->u.insert.d = cdata;
+       if (flags == 0)
+               flags = znode_get_tree(coord->node)->carry.insert_flags;
+       op->u.insert.flags = flags;
+       op->u.insert.type = COPT_ITEM_DATA;
+       op->u.insert.child = NULL;
+       if (lh != NULL) {
+               assert("nikita-3245", lh->node == coord->node);
+               lowest_level->track_type = CARRY_TRACK_CHANGE;
+               lowest_level->tracked = lh;
+       }
+
+       result = reiser4_carry(lowest_level, NULL);
+       done_carry_pool(pool);
+
+       return result;
+}
+
+/* form carry queue to perform paste of @data with @key at @coord, and launch
+   its execution by calling carry().
+
+   Instruct carry to update @lh it after balancing insertion coord moves into
+   different block.
+
+*/
+static int paste_with_carry(coord_t * coord,   /* coord of paste */
+                           lock_handle * lh,   /* lock handle of node
+                                                * where item is
+                                                * pasted */
+                           reiser4_item_data * data,   /* parameters of new
+                                                        * item */
+                           const reiser4_key * key,    /* key of new item */
+                           unsigned flags /* paste flags */ )
+{
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       carry_insert_data *cdata;
+       carry_op *op;
+
+       assert("umka-315", coord != NULL);
+       assert("umka-316", key != NULL);
+
+       pool =
+           init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                           sizeof(*cdata));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+
+       op = reiser4_post_carry(lowest_level, COP_PASTE, coord->node, 0);
+       if (IS_ERR(op) || (op == NULL)) {
+               done_carry_pool(pool);
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+       }
+       cdata = (carry_insert_data *) (lowest_level + 3);
+       cdata->coord = coord;
+       cdata->data = data;
+       cdata->key = key;
+       op->u.paste.d = cdata;
+       if (flags == 0)
+               flags = znode_get_tree(coord->node)->carry.paste_flags;
+       op->u.paste.flags = flags;
+       op->u.paste.type = COPT_ITEM_DATA;
+       if (lh != NULL) {
+               lowest_level->track_type = CARRY_TRACK_CHANGE;
+               lowest_level->tracked = lh;
+       }
+
+       result = reiser4_carry(lowest_level, NULL);
+       done_carry_pool(pool);
+
+       return result;
+}
+
+/* insert item at the given coord.
+
+   First try to skip carry by directly calling ->create_item() method of node
+   plugin. If this is impossible (there is not enough free space in the node,
+   or leftmost item in the node is created), call insert_with_carry_by_coord()
+   that will do full carry().
+
+*/
+insert_result insert_by_coord(coord_t * coord  /* coord where to
+                                                * insert. coord->node has
+                                                * to be write locked by
+                                                * caller */ ,
+                             reiser4_item_data * data  /* data to be
+                                                        * inserted */ ,
+                             const reiser4_key * key /* key of new item */ ,
+                             lock_handle * lh  /* lock handle of write
+                                                * lock on node */ ,
+                             __u32 flags /* insertion flags */ )
+{
+       unsigned item_size;
+       int result;
+       znode *node;
+
+       assert("vs-247", coord != NULL);
+       assert("vs-248", data != NULL);
+       assert("vs-249", data->length >= 0);
+       assert("nikita-1191", znode_is_write_locked(coord->node));
+
+       node = coord->node;
+       coord_clear_iplug(coord);
+       result = zload(node);
+       if (result != 0)
+               return result;
+
+       item_size = space_needed(node, NULL, data, 1);
+       if (item_size > znode_free_space(node) &&
+           (flags & COPI_DONT_SHIFT_LEFT) && (flags & COPI_DONT_SHIFT_RIGHT)
+           && (flags & COPI_DONT_ALLOCATE)) {
+               /* we are forced to use free space of coord->node and new item
+                  does not fit into it.
+
+                  Currently we get here only when we allocate and copy units
+                  of extent item from a node to its left neighbor during
+                  "squalloc"-ing.  If @node (this is left neighbor) does not
+                  have enough free space - we do not want to attempt any
+                  shifting and allocations because we are in squeezing and
+                  everything to the left of @node is tightly packed.
+                */
+               result = -E_NODE_FULL;
+       } else if ((item_size <= znode_free_space(node)) &&
+                  !coord_is_before_leftmost(coord) &&
+                  (node_plugin_by_node(node)->fast_insert != NULL)
+                  && node_plugin_by_node(node)->fast_insert(coord)) {
+               /* shortcut insertion without carry() overhead.
+
+                  Only possible if:
+
+                  - there is enough free space
+
+                  - insertion is not into the leftmost position in a node
+                  (otherwise it would require updating of delimiting key in a
+                  parent)
+
+                  - node plugin agrees with this
+
+                */
+               result =
+                   node_plugin_by_node(node)->create_item(coord, key, data,
+                                                          NULL);
+               znode_make_dirty(node);
+       } else {
+               /* otherwise do full-fledged carry(). */
+               result =
+                   insert_with_carry_by_coord(coord, lh, data, key, COP_INSERT,
+                                              flags);
+       }
+       zrelse(node);
+       return result;
+}
+
+/* @coord is set to leaf level and @data is to be inserted to twig level */
+insert_result
+insert_extent_by_coord(coord_t *
+                      coord
+                      /* coord where to insert. coord->node * has to be write * locked by caller */
+                      ,
+                      reiser4_item_data * data /* data to be inserted */ ,
+                      const reiser4_key * key /* key of new item */ ,
+                      lock_handle *
+                      lh /* lock handle of write lock on * node */ )
+{
+       assert("vs-405", coord != NULL);
+       assert("vs-406", data != NULL);
+       assert("vs-407", data->length > 0);
+       assert("vs-408", znode_is_write_locked(coord->node));
+       assert("vs-409", znode_get_level(coord->node) == LEAF_LEVEL);
+
+       return insert_with_carry_by_coord(coord, lh, data, key, COP_EXTENT,
+                                         0 /*flags */ );
+}
+
+/* Insert into the item at the given coord.
+
+   First try to skip carry by directly calling ->paste() method of item
+   plugin. If this is impossible (there is not enough free space in the node,
+   or we are pasting into leftmost position in the node), call
+   paste_with_carry() that will do full carry().
+
+*/
+/* paste_into_item */
+int insert_into_item(coord_t * coord /* coord of pasting */ ,
+                    lock_handle * lh /* lock handle on node involved */ ,
+                    const reiser4_key * key /* key of unit being pasted */ ,
+                    reiser4_item_data * data /* parameters for new unit */ ,
+                    unsigned flags /* insert/paste flags */ )
+{
+       int result;
+       int size_change;
+       node_plugin *nplug;
+       item_plugin *iplug;
+
+       assert("umka-317", coord != NULL);
+       assert("umka-318", key != NULL);
+
+       iplug = item_plugin_by_coord(coord);
+       nplug = node_plugin_by_coord(coord);
+
+       assert("nikita-1480", iplug == data->iplug);
+
+       size_change = space_needed(coord->node, coord, data, 0);
+       if (size_change > (int)znode_free_space(coord->node) &&
+           (flags & COPI_DONT_SHIFT_LEFT) && (flags & COPI_DONT_SHIFT_RIGHT)
+           && (flags & COPI_DONT_ALLOCATE)) {
+               /* we are forced to use free space of coord->node and new data
+                  does not fit into it. */
+               return -E_NODE_FULL;
+       }
+
+       /* shortcut paste without carry() overhead.
+
+          Only possible if:
+
+          - there is enough free space
+
+          - paste is not into the leftmost unit in a node (otherwise
+          it would require updating of delimiting key in a parent)
+
+          - node plugin agrees with this
+
+          - item plugin agrees with us
+        */
+       if (size_change <= (int)znode_free_space(coord->node) &&
+           (coord->item_pos != 0 ||
+            coord->unit_pos != 0 || coord->between == AFTER_UNIT) &&
+           coord->unit_pos != 0 && nplug->fast_paste != NULL &&
+           nplug->fast_paste(coord) &&
+           iplug->b.fast_paste != NULL && iplug->b.fast_paste(coord)) {
+               if (size_change > 0)
+                       nplug->change_item_size(coord, size_change);
+               /* NOTE-NIKITA: huh? where @key is used? */
+               result = iplug->b.paste(coord, data, NULL);
+               if (size_change < 0)
+                       nplug->change_item_size(coord, size_change);
+               znode_make_dirty(coord->node);
+       } else
+               /* otherwise do full-fledged carry(). */
+               result = paste_with_carry(coord, lh, data, key, flags);
+       return result;
+}
+
+/* this either appends or truncates item @coord */
+int reiser4_resize_item(coord_t * coord /* coord of item being resized */ ,
+                       reiser4_item_data * data /* parameters of resize */ ,
+                       reiser4_key * key /* key of new unit */ ,
+                       lock_handle * lh        /* lock handle of node
+                                                * being modified */ ,
+                       cop_insert_flag flags /* carry flags */ )
+{
+       int result;
+       znode *node;
+
+       assert("nikita-362", coord != NULL);
+       assert("nikita-363", data != NULL);
+       assert("vs-245", data->length != 0);
+
+       node = coord->node;
+       coord_clear_iplug(coord);
+       result = zload(node);
+       if (result != 0)
+               return result;
+
+       if (data->length < 0)
+               result = node_plugin_by_coord(coord)->shrink_item(coord,
+                                                                 -data->length);
+       else
+               result = insert_into_item(coord, lh, key, data, flags);
+
+       zrelse(node);
+       return result;
+}
+
+/* insert flow @f */
+int reiser4_insert_flow(coord_t * coord, lock_handle * lh, flow_t * f)
+{
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       reiser4_item_data *data;
+       carry_op *op;
+
+       pool =
+           init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                           sizeof(*data));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+
+       op = reiser4_post_carry(lowest_level, COP_INSERT_FLOW, coord->node,
+                       0 /* operate directly on coord -> node */ );
+       if (IS_ERR(op) || (op == NULL)) {
+               done_carry_pool(pool);
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+       }
+
+       /* these are permanent during insert_flow */
+       data = (reiser4_item_data *) (lowest_level + 3);
+       data->user = 1;
+       data->iplug = item_plugin_by_id(FORMATTING_ID);
+       data->arg = NULL;
+       /* data.length and data.data will be set before calling paste or
+          insert */
+       data->length = 0;
+       data->data = NULL;
+
+       op->u.insert_flow.flags = 0;
+       op->u.insert_flow.insert_point = coord;
+       op->u.insert_flow.flow = f;
+       op->u.insert_flow.data = data;
+       op->u.insert_flow.new_nodes = 0;
+
+       lowest_level->track_type = CARRY_TRACK_CHANGE;
+       lowest_level->tracked = lh;
+
+       result = reiser4_carry(lowest_level, NULL);
+       done_carry_pool(pool);
+
+       return result;
+}
+
+/* Given a coord in parent node, obtain a znode for the corresponding child */
+znode *child_znode(const coord_t * parent_coord        /* coord of pointer to
+                                                * child */ ,
+                  znode * parent /* parent of child */ ,
+                  int incore_p /* if !0 only return child if already in
+                                * memory */ ,
+                  int setup_dkeys_p    /* if !0 update delimiting keys of
+                                        * child */ )
+{
+       znode *child;
+
+       assert("nikita-1374", parent_coord != NULL);
+       assert("nikita-1482", parent != NULL);
+#if REISER4_DEBUG
+       if (setup_dkeys_p)
+               assert_rw_not_locked(&(znode_get_tree(parent)->dk_lock));
+#endif
+       assert("nikita-2947", znode_is_any_locked(parent));
+
+       if (znode_get_level(parent) <= LEAF_LEVEL) {
+               /* trying to get child of leaf node */
+               warning("nikita-1217", "Child of maize?");
+               return ERR_PTR(RETERR(-EIO));
+       }
+       if (item_is_internal(parent_coord)) {
+               reiser4_block_nr addr;
+               item_plugin *iplug;
+               reiser4_tree *tree;
+
+               iplug = item_plugin_by_coord(parent_coord);
+               assert("vs-512", iplug->s.internal.down_link);
+               iplug->s.internal.down_link(parent_coord, NULL, &addr);
+
+               tree = znode_get_tree(parent);
+               if (incore_p)
+                       child = zlook(tree, &addr);
+               else
+                       child =
+                           zget(tree, &addr, parent,
+                                znode_get_level(parent) - 1,
+                                reiser4_ctx_gfp_mask_get());
+               if ((child != NULL) && !IS_ERR(child) && setup_dkeys_p)
+                       set_child_delimiting_keys(parent, parent_coord, child);
+       } else {
+               warning("nikita-1483", "Internal item expected");
+               child = ERR_PTR(RETERR(-EIO));
+       }
+       return child;
+}
+
+/* remove znode from transaction */
+static void uncapture_znode(znode * node)
+{
+       struct page *page;
+
+       assert("zam-1001", ZF_ISSET(node, JNODE_HEARD_BANSHEE));
+
+       if (!reiser4_blocknr_is_fake(znode_get_block(node))) {
+               int ret;
+
+               /* An already allocated block goes right to the atom's delete set. */
+               ret =
+                   reiser4_dealloc_block(znode_get_block(node), 0,
+                                         BA_DEFER | BA_FORMATTED);
+               if (ret)
+                       warning("zam-942",
+                               "can\'t add a block (%llu) number to atom's delete set\n",
+                               (unsigned long long)(*znode_get_block(node)));
+
+               spin_lock_znode(node);
+               /* Here we return flush reserved block which was reserved at the
+                * moment when this allocated node was marked dirty and still
+                * not used by flush in node relocation procedure.  */
+               if (ZF_ISSET(node, JNODE_FLUSH_RESERVED)) {
+                       txn_atom *atom;
+
+                       atom = jnode_get_atom(ZJNODE(node));
+                       assert("zam-939", atom != NULL);
+                       spin_unlock_znode(node);
+                       flush_reserved2grabbed(atom, (__u64) 1);
+                       spin_unlock_atom(atom);
+               } else
+                       spin_unlock_znode(node);
+       } else {
+               /* znode has assigned block which is counted as "fake
+                  allocated". Return it back to "free blocks") */
+               fake_allocated2free((__u64) 1, BA_FORMATTED);
+       }
+
+       /*
+        * uncapture page from transaction. There is a possibility of a race
+        * with ->releasepage(): reiser4_releasepage() detaches page from this
+        * jnode and we have nothing to uncapture. To avoid this, get
+        * reference of node->pg under jnode spin lock. reiser4_uncapture_page()
+        * will deal with released page itself.
+        */
+       spin_lock_znode(node);
+       page = znode_page(node);
+       if (likely(page != NULL)) {
+               /*
+                * reiser4_uncapture_page() can only be called when we are sure
+                * that znode is pinned in memory, which we are, because
+                * forget_znode() is only called from longterm_unlock_znode().
+                */
+               page_cache_get(page);
+               spin_unlock_znode(node);
+               lock_page(page);
+               reiser4_uncapture_page(page);
+               unlock_page(page);
+               page_cache_release(page);
+       } else {
+               txn_atom *atom;
+
+               /* handle "flush queued" znodes */
+               while (1) {
+                       atom = jnode_get_atom(ZJNODE(node));
+                       assert("zam-943", atom != NULL);
+
+                       if (!ZF_ISSET(node, JNODE_FLUSH_QUEUED)
+                           || !atom->nr_running_queues)
+                               break;
+
+                       spin_unlock_znode(node);
+                       reiser4_atom_wait_event(atom);
+                       spin_lock_znode(node);
+               }
+
+               reiser4_uncapture_block(ZJNODE(node));
+               spin_unlock_atom(atom);
+               zput(node);
+       }
+}
+
+/* This is called from longterm_unlock_znode() when last lock is released from
+   the node that has been removed from the tree. At this point node is removed
+   from sibling list and its lock is invalidated. */
+void forget_znode(lock_handle * handle)
+{
+       znode *node;
+       reiser4_tree *tree;
+
+       assert("umka-319", handle != NULL);
+
+       node = handle->node;
+       tree = znode_get_tree(node);
+
+       assert("vs-164", znode_is_write_locked(node));
+       assert("nikita-1280", ZF_ISSET(node, JNODE_HEARD_BANSHEE));
+       assert_rw_locked(&(node->lock.guard));
+
+       /* We assume that this node was detached from its parent before
+        * unlocking, it gives no way to reach this node from parent through a
+        * down link.  The node should have no children and, thereby, can't be
+        * reached from them by their parent pointers.  The only way to obtain a
+        * reference to the node is to use sibling pointers from its left and
+        * right neighbors.  In the next several lines we remove the node from
+        * the sibling list. */
+
+       write_lock_tree(tree);
+       sibling_list_remove(node);
+       znode_remove(node, tree);
+       write_unlock_tree(tree);
+
+       /* Here we set JNODE_DYING and cancel all pending lock requests.  It
+        * forces all lock requestor threads to repeat iterations of getting
+        * lock on a child, neighbor or parent node.  But, those threads can't
+        * come to this node again, because this node is no longer a child,
+        * neighbor or parent of any other node.  This order of znode
+        * invalidation does not allow other threads to waste cpu time is a busy
+        * loop, trying to lock dying object.  The exception is in the flush
+        * code when we take node directly from atom's capture list.*/
+       reiser4_invalidate_lock(handle);
+       uncapture_znode(node);
+}
+
+/* Check that internal item at @pointer really contains pointer to @child. */
+int check_tree_pointer(const coord_t * pointer /* would-be pointer to
+                                                * @child */ ,
+                      const znode * child /* child znode */ )
+{
+       assert("nikita-1016", pointer != NULL);
+       assert("nikita-1017", child != NULL);
+       assert("nikita-1018", pointer->node != NULL);
+
+       assert("nikita-1325", znode_is_any_locked(pointer->node));
+
+       assert("nikita-2985",
+              znode_get_level(pointer->node) == znode_get_level(child) + 1);
+
+       coord_clear_iplug((coord_t *) pointer);
+
+       if (coord_is_existing_unit(pointer)) {
+               item_plugin *iplug;
+               reiser4_block_nr addr;
+
+               if (item_is_internal(pointer)) {
+                       iplug = item_plugin_by_coord(pointer);
+                       assert("vs-513", iplug->s.internal.down_link);
+                       iplug->s.internal.down_link(pointer, NULL, &addr);
+                       /* check that cached value is correct */
+                       if (disk_addr_eq(&addr, znode_get_block(child))) {
+                               return NS_FOUND;
+                       }
+               }
+       }
+       /* warning ("jmacd-1002", "tree pointer incorrect"); */
+       return NS_NOT_FOUND;
+}
+
+/* find coord of pointer to new @child in @parent.
+
+   Find the &coord_t in the @parent where pointer to a given @child will
+   be in.
+
+*/
+int find_new_child_ptr(znode * parent /* parent znode, passed locked */ ,
+                      znode *
+                      child UNUSED_ARG /* child znode, passed locked */ ,
+                      znode * left /* left brother of new node */ ,
+                      coord_t * result /* where result is stored in */ )
+{
+       int ret;
+
+       assert("nikita-1486", parent != NULL);
+       assert("nikita-1487", child != NULL);
+       assert("nikita-1488", result != NULL);
+
+       ret = find_child_ptr(parent, left, result);
+       if (ret != NS_FOUND) {
+               warning("nikita-1489", "Cannot find brother position: %i", ret);
+               return RETERR(-EIO);
+       } else {
+               result->between = AFTER_UNIT;
+               return RETERR(NS_NOT_FOUND);
+       }
+}
+
+/* find coord of pointer to @child in @parent.
+
+   Find the &coord_t in the @parent where pointer to a given @child is in.
+
+*/
+int find_child_ptr(znode * parent /* parent znode, passed locked */ ,
+                  znode * child /* child znode, passed locked */ ,
+                  coord_t * result /* where result is stored in */ )
+{
+       int lookup_res;
+       node_plugin *nplug;
+       /* left delimiting key of a child */
+       reiser4_key ld;
+       reiser4_tree *tree;
+
+       assert("nikita-934", parent != NULL);
+       assert("nikita-935", child != NULL);
+       assert("nikita-936", result != NULL);
+       assert("zam-356", znode_is_loaded(parent));
+
+       coord_init_zero(result);
+       result->node = parent;
+
+       nplug = parent->nplug;
+       assert("nikita-939", nplug != NULL);
+
+       tree = znode_get_tree(parent);
+       /* NOTE-NIKITA taking read-lock on tree here assumes that @result is
+        * not aliased to ->in_parent of some znode. Otherwise,
+        * parent_coord_to_coord() below would modify data protected by tree
+        * lock. */
+       read_lock_tree(tree);
+       /* fast path. Try to use cached value. Lock tree to keep
+          node->pos_in_parent and pos->*_blocknr consistent. */
+       if (child->in_parent.item_pos + 1 != 0) {
+               parent_coord_to_coord(&child->in_parent, result);
+               if (check_tree_pointer(result, child) == NS_FOUND) {
+                       read_unlock_tree(tree);
+                       return NS_FOUND;
+               }
+
+               child->in_parent.item_pos = (unsigned short)~0;
+       }
+       read_unlock_tree(tree);
+
+       /* is above failed, find some key from @child. We are looking for the
+          least key in a child. */
+       read_lock_dk(tree);
+       ld = *znode_get_ld_key(child);
+       read_unlock_dk(tree);
+       /*
+        * now, lookup parent with key just found. Note, that left delimiting
+        * key doesn't identify node uniquely, because (in extremely rare
+        * case) two nodes can have equal left delimiting keys, if one of them
+        * is completely filled with directory entries that all happened to be
+        * hash collision. But, we check block number in check_tree_pointer()
+        * and, so, are safe.
+        */
+       lookup_res = nplug->lookup(parent, &ld, FIND_EXACT, result);
+       /* update cached pos_in_node */
+       if (lookup_res == NS_FOUND) {
+               write_lock_tree(tree);
+               coord_to_parent_coord(result, &child->in_parent);
+               write_unlock_tree(tree);
+               lookup_res = check_tree_pointer(result, child);
+       }
+       if (lookup_res == NS_NOT_FOUND)
+               lookup_res = find_child_by_addr(parent, child, result);
+       return lookup_res;
+}
+
+/* find coord of pointer to @child in @parent by scanning
+
+   Find the &coord_t in the @parent where pointer to a given @child
+   is in by scanning all internal items in @parent and comparing block
+   numbers in them with that of @child.
+
+*/
+static int find_child_by_addr(znode * parent /* parent znode, passed locked */ ,
+                             znode * child /* child znode, passed locked */ ,
+                             coord_t * result /* where result is stored in */ )
+{
+       int ret;
+
+       assert("nikita-1320", parent != NULL);
+       assert("nikita-1321", child != NULL);
+       assert("nikita-1322", result != NULL);
+
+       ret = NS_NOT_FOUND;
+
+       for_all_units(result, parent) {
+               if (check_tree_pointer(result, child) == NS_FOUND) {
+                       write_lock_tree(znode_get_tree(parent));
+                       coord_to_parent_coord(result, &child->in_parent);
+                       write_unlock_tree(znode_get_tree(parent));
+                       ret = NS_FOUND;
+                       break;
+               }
+       }
+       return ret;
+}
+
+/* true, if @addr is "unallocated block number", which is just address, with
+   highest bit set. */
+int is_disk_addr_unallocated(const reiser4_block_nr * addr     /* address to
+                                                                * check */ )
+{
+       assert("nikita-1766", addr != NULL);
+       cassert(sizeof(reiser4_block_nr) == 8);
+       return (*addr & REISER4_BLOCKNR_STATUS_BIT_MASK) ==
+           REISER4_UNALLOCATED_STATUS_VALUE;
+}
+
+/* returns true if removing bytes of given range of key [from_key, to_key]
+   causes removing of whole item @from */
+static int
+item_removed_completely(coord_t * from, const reiser4_key * from_key,
+                       const reiser4_key * to_key)
+{
+       item_plugin *iplug;
+       reiser4_key key_in_item;
+
+       assert("umka-325", from != NULL);
+       assert("", item_is_extent(from));
+
+       /* check first key just for case */
+       item_key_by_coord(from, &key_in_item);
+       if (keygt(from_key, &key_in_item))
+               return 0;
+
+       /* check last key */
+       iplug = item_plugin_by_coord(from);
+       assert("vs-611", iplug && iplug->s.file.append_key);
+
+       iplug->s.file.append_key(from, &key_in_item);
+       set_key_offset(&key_in_item, get_key_offset(&key_in_item) - 1);
+
+       if (keylt(to_key, &key_in_item))
+               /* last byte is not removed */
+               return 0;
+       return 1;
+}
+
+/* helper function for prepare_twig_kill(): @left and @right are formatted
+ * neighbors of extent item being completely removed. Load and lock neighbors
+ * and store lock handles into @cdata for later use by kill_hook_extent() */
+static int
+prepare_children(znode * left, znode * right, carry_kill_data * kdata)
+{
+       int result;
+       int left_loaded;
+       int right_loaded;
+
+       result = 0;
+       left_loaded = right_loaded = 0;
+
+       if (left != NULL) {
+               result = zload(left);
+               if (result == 0) {
+                       left_loaded = 1;
+                       result = longterm_lock_znode(kdata->left, left,
+                                                    ZNODE_READ_LOCK,
+                                                    ZNODE_LOCK_LOPRI);
+               }
+       }
+       if (result == 0 && right != NULL) {
+               result = zload(right);
+               if (result == 0) {
+                       right_loaded = 1;
+                       result = longterm_lock_znode(kdata->right, right,
+                                                    ZNODE_READ_LOCK,
+                                                    ZNODE_LOCK_HIPRI |
+                                                    ZNODE_LOCK_NONBLOCK);
+               }
+       }
+       if (result != 0) {
+               done_lh(kdata->left);
+               done_lh(kdata->right);
+               if (left_loaded != 0)
+                       zrelse(left);
+               if (right_loaded != 0)
+                       zrelse(right);
+       }
+       return result;
+}
+
+static void done_children(carry_kill_data * kdata)
+{
+       if (kdata->left != NULL && kdata->left->node != NULL) {
+               zrelse(kdata->left->node);
+               done_lh(kdata->left);
+       }
+       if (kdata->right != NULL && kdata->right->node != NULL) {
+               zrelse(kdata->right->node);
+               done_lh(kdata->right);
+       }
+}
+
+/* part of cut_node. It is called when cut_node is called to remove or cut part
+   of extent item. When head of that item is removed - we have to update right
+   delimiting of left neighbor of extent. When item is removed completely - we
+   have to set sibling link between left and right neighbor of removed
+   extent. This may return -E_DEADLOCK because of trying to get left neighbor
+   locked. So, caller should repeat an attempt
+*/
+/* Audited by: umka (2002.06.16) */
+static int
+prepare_twig_kill(carry_kill_data * kdata, znode * locked_left_neighbor)
+{
+       int result;
+       reiser4_key key;
+       lock_handle left_lh;
+       lock_handle right_lh;
+       coord_t left_coord;
+       coord_t *from;
+       znode *left_child;
+       znode *right_child;
+       reiser4_tree *tree;
+       int left_zloaded_here, right_zloaded_here;
+
+       from = kdata->params.from;
+       assert("umka-326", from != NULL);
+       assert("umka-327", kdata->params.to != NULL);
+
+       /* for one extent item only yet */
+       assert("vs-591", item_is_extent(from));
+       assert("vs-592", from->item_pos == kdata->params.to->item_pos);
+
+       if ((kdata->params.from_key
+            && keygt(kdata->params.from_key, item_key_by_coord(from, &key)))
+           || from->unit_pos != 0) {
+               /* head of item @from is not removed, there is nothing to
+                  worry about */
+               return 0;
+       }
+
+       result = 0;
+       left_zloaded_here = 0;
+       right_zloaded_here = 0;
+
+       left_child = right_child = NULL;
+
+       coord_dup(&left_coord, from);
+       init_lh(&left_lh);
+       init_lh(&right_lh);
+       if (coord_prev_unit(&left_coord)) {
+               /* @from is leftmost item in its node */
+               if (!locked_left_neighbor) {
+                       result =
+                           reiser4_get_left_neighbor(&left_lh, from->node,
+                                                     ZNODE_READ_LOCK,
+                                                     GN_CAN_USE_UPPER_LEVELS);
+                       switch (result) {
+                       case 0:
+                               break;
+                       case -E_NO_NEIGHBOR:
+                               /* there is no formatted node to the left of
+                                  from->node */
+                               warning("vs-605",
+                                       "extent item has smallest key in "
+                                       "the tree and it is about to be removed");
+                               return 0;
+                       case -E_DEADLOCK:
+                               /* need to restart */
+                       default:
+                               return result;
+                       }
+
+                       /* we have acquired left neighbor of from->node */
+                       result = zload(left_lh.node);
+                       if (result)
+                               goto done;
+
+                       locked_left_neighbor = left_lh.node;
+               } else {
+                       /* squalloc_right_twig_cut should have supplied locked
+                        * left neighbor */
+                       assert("vs-834",
+                              znode_is_write_locked(locked_left_neighbor));
+                       result = zload(locked_left_neighbor);
+                       if (result)
+                               return result;
+               }
+
+               left_zloaded_here = 1;
+               coord_init_last_unit(&left_coord, locked_left_neighbor);
+       }
+
+       if (!item_is_internal(&left_coord)) {
+               /* what else but extent can be on twig level */
+               assert("vs-606", item_is_extent(&left_coord));
+
+               /* there is no left formatted child */
+               if (left_zloaded_here)
+                       zrelse(locked_left_neighbor);
+               done_lh(&left_lh);
+               return 0;
+       }
+
+       tree = znode_get_tree(left_coord.node);
+       left_child = child_znode(&left_coord, left_coord.node, 1, 0);
+
+       if (IS_ERR(left_child)) {
+               result = PTR_ERR(left_child);
+               goto done;
+       }
+
+       /* left child is acquired, calculate new right delimiting key for it
+          and get right child if it is necessary */
+       if (item_removed_completely
+           (from, kdata->params.from_key, kdata->params.to_key)) {
+               /* try to get right child of removed item */
+               coord_t right_coord;
+
+               assert("vs-607",
+                      kdata->params.to->unit_pos ==
+                      coord_last_unit_pos(kdata->params.to));
+               coord_dup(&right_coord, kdata->params.to);
+               if (coord_next_unit(&right_coord)) {
+                       /* @to is rightmost unit in the node */
+                       result =
+                           reiser4_get_right_neighbor(&right_lh, from->node,
+                                                      ZNODE_READ_LOCK,
+                                                      GN_CAN_USE_UPPER_LEVELS);
+                       switch (result) {
+                       case 0:
+                               result = zload(right_lh.node);
+                               if (result)
+                                       goto done;
+
+                               right_zloaded_here = 1;
+                               coord_init_first_unit(&right_coord,
+                                                     right_lh.node);
+                               item_key_by_coord(&right_coord, &key);
+                               break;
+
+                       case -E_NO_NEIGHBOR:
+                               /* there is no formatted node to the right of
+                                  from->node */
+                               read_lock_dk(tree);
+                               key = *znode_get_rd_key(from->node);
+                               read_unlock_dk(tree);
+                               right_coord.node = NULL;
+                               result = 0;
+                               break;
+                       default:
+                               /* real error */
+                               goto done;
+                       }
+               } else {
+                       /* there is an item to the right of @from - take its key */
+                       item_key_by_coord(&right_coord, &key);
+               }
+
+               /* try to get right child of @from */
+               if (right_coord.node && /* there is right neighbor of @from */
+                   item_is_internal(&right_coord)) {   /* it is internal item */
+                       right_child = child_znode(&right_coord,
+                                                 right_coord.node, 1, 0);
+
+                       if (IS_ERR(right_child)) {
+                               result = PTR_ERR(right_child);
+                               goto done;
+                       }
+
+               }
+               /* whole extent is removed between znodes left_child and right_child. Prepare them for linking and
+                  update of right delimiting key of left_child */
+               result = prepare_children(left_child, right_child, kdata);
+       } else {
+               /* head of item @to is removed. left_child has to get right delimting key update. Prepare it for that */
+               result = prepare_children(left_child, NULL, kdata);
+       }
+
+      done:
+       if (right_child)
+               zput(right_child);
+       if (right_zloaded_here)
+               zrelse(right_lh.node);
+       done_lh(&right_lh);
+
+       if (left_child)
+               zput(left_child);
+       if (left_zloaded_here)
+               zrelse(locked_left_neighbor);
+       done_lh(&left_lh);
+       return result;
+}
+
+/* this is used to remove part of node content between coordinates @from and @to. Units to which @from and @to are set
+   are to be cut completely */
+/* for try_to_merge_with_left, delete_copied, reiser4_delete_node */
+int cut_node_content(coord_t * from, coord_t * to, const reiser4_key * from_key,       /* first key to be removed */
+                    const reiser4_key * to_key,        /* last key to be removed */
+                    reiser4_key *
+                    smallest_removed /* smallest key actually removed */ )
+{
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       carry_cut_data *cut_data;
+       carry_op *op;
+
+       assert("vs-1715", coord_compare(from, to) != COORD_CMP_ON_RIGHT);
+
+       pool =
+           init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                           sizeof(*cut_data));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+
+       op = reiser4_post_carry(lowest_level, COP_CUT, from->node, 0);
+       assert("vs-1509", op != 0);
+       if (IS_ERR(op)) {
+               done_carry_pool(pool);
+               return PTR_ERR(op);
+       }
+
+       cut_data = (carry_cut_data *) (lowest_level + 3);
+       cut_data->params.from = from;
+       cut_data->params.to = to;
+       cut_data->params.from_key = from_key;
+       cut_data->params.to_key = to_key;
+       cut_data->params.smallest_removed = smallest_removed;
+
+       op->u.cut_or_kill.is_cut = 1;
+       op->u.cut_or_kill.u.cut = cut_data;
+
+       result = reiser4_carry(lowest_level, NULL);
+       done_carry_pool(pool);
+
+       return result;
+}
+
+/* cut part of the node
+
+   Cut part or whole content of node.
+
+   cut data between @from and @to of @from->node and call carry() to make
+   corresponding changes in the tree. @from->node may become empty. If so -
+   pointer to it will be removed. Neighboring nodes are not changed. Smallest
+   removed key is stored in @smallest_removed
+
+*/
+int kill_node_content(coord_t * from,  /* coord of the first unit/item that will be eliminated */
+                     coord_t * to,     /* coord of the last unit/item that will be eliminated */
+                     const reiser4_key * from_key,     /* first key to be removed */
+                     const reiser4_key * to_key,       /* last key to be removed */
+                     reiser4_key * smallest_removed,   /* smallest key actually removed */
+                     znode * locked_left_neighbor,     /* this is set when kill_node_content is called with left neighbor
+                                                        * locked (in squalloc_right_twig_cut, namely) */
+                     struct inode *inode,      /* inode of file whose item (or its part) is to be killed. This is necessary to
+                                                  invalidate pages together with item pointing to them */
+                     int truncate)
+{                              /* this call is made for file truncate)  */
+       int result;
+       carry_pool *pool;
+       carry_level *lowest_level;
+       carry_kill_data *kdata;
+       lock_handle *left_child;
+       lock_handle *right_child;
+       carry_op *op;
+
+       assert("umka-328", from != NULL);
+       assert("vs-316", !node_is_empty(from->node));
+       assert("nikita-1812", coord_is_existing_unit(from)
+              && coord_is_existing_unit(to));
+
+       /* allocate carry_pool, 3 carry_level-s, carry_kill_data and structures for kill_hook_extent */
+       pool = init_carry_pool(sizeof(*pool) + 3 * sizeof(*lowest_level) +
+                              sizeof(carry_kill_data) +
+                              2 * sizeof(lock_handle) +
+                              5 * sizeof(reiser4_key) + 2 * sizeof(coord_t));
+       if (IS_ERR(pool))
+               return PTR_ERR(pool);
+
+       lowest_level = (carry_level *) (pool + 1);
+       init_carry_level(lowest_level, pool);
+
+       kdata = (carry_kill_data *) (lowest_level + 3);
+       left_child = (lock_handle *) (kdata + 1);
+       right_child = left_child + 1;
+
+       init_lh(left_child);
+       init_lh(right_child);
+
+       kdata->params.from = from;
+       kdata->params.to = to;
+       kdata->params.from_key = from_key;
+       kdata->params.to_key = to_key;
+       kdata->params.smallest_removed = smallest_removed;
+       kdata->params.truncate = truncate;
+       kdata->flags = 0;
+       kdata->inode = inode;
+       kdata->left = left_child;
+       kdata->right = right_child;
+       /* memory for 5 reiser4_key and 2 coord_t will be used in kill_hook_extent */
+       kdata->buf = (char *)(right_child + 1);
+
+       if (znode_get_level(from->node) == TWIG_LEVEL && item_is_extent(from)) {
+               /* left child of extent item may have to get updated right
+                  delimiting key and to get linked with right child of extent
+                  @from if it will be removed completely */
+               result = prepare_twig_kill(kdata, locked_left_neighbor);
+               if (result) {
+                       done_children(kdata);
+                       done_carry_pool(pool);
+                       return result;
+               }
+       }
+
+       op = reiser4_post_carry(lowest_level, COP_CUT, from->node, 0);
+       if (IS_ERR(op) || (op == NULL)) {
+               done_children(kdata);
+               done_carry_pool(pool);
+               return RETERR(op ? PTR_ERR(op) : -EIO);
+       }
+
+       op->u.cut_or_kill.is_cut = 0;
+       op->u.cut_or_kill.u.kill = kdata;
+
+       result = reiser4_carry(lowest_level, NULL);
+
+       done_children(kdata);
+       done_carry_pool(pool);
+       return result;
+}
+
+void
+fake_kill_hook_tail(struct inode *inode, loff_t start, loff_t end, int truncate)
+{
+       if (reiser4_inode_get_flag(inode, REISER4_HAS_MMAP)) {
+               pgoff_t start_pg, end_pg;
+
+               start_pg = start >> PAGE_CACHE_SHIFT;
+               end_pg = (end - 1) >> PAGE_CACHE_SHIFT;
+
+               if ((start & (PAGE_CACHE_SIZE - 1)) == 0) {
+                       /*
+                        * kill up to the page boundary.
+                        */
+                       assert("vs-123456", start_pg == end_pg);
+                       reiser4_invalidate_pages(inode->i_mapping, start_pg, 1,
+                                                truncate);
+               } else if (start_pg != end_pg) {
+                       /*
+                        * page boundary is within killed portion of node.
+                        */
+                       assert("vs-654321", end_pg - start_pg == 1);
+                       reiser4_invalidate_pages(inode->i_mapping, end_pg,
+                                                end_pg - start_pg, 1);
+               }
+       }
+       inode_sub_bytes(inode, end - start);
+}
+
+/**
+ * Delete whole @node from the reiser4 tree without loading it.
+ *
+ * @left: locked left neighbor,
+ * @node: node to be deleted,
+ * @smallest_removed: leftmost key of deleted node,
+ * @object: inode pointer, if we truncate a file body.
+ * @truncate: true if called for file truncate.
+ *
+ * @return: 0 if success, error code otherwise.
+ *
+ * NOTE: if @object!=NULL we assume that @smallest_removed != NULL and it
+ * contains the right value of the smallest removed key from the previous
+ * cut_worker() iteration.  This is needed for proper accounting of
+ * "i_blocks" and "i_bytes" fields of the @object.
+ */
+int reiser4_delete_node(znode * node, reiser4_key * smallest_removed,
+                       struct inode *object, int truncate)
+{
+       lock_handle parent_lock;
+       coord_t cut_from;
+       coord_t cut_to;
+       reiser4_tree *tree;
+       int ret;
+
+       assert("zam-937", node != NULL);
+       assert("zam-933", znode_is_write_locked(node));
+       assert("zam-999", smallest_removed != NULL);
+
+       init_lh(&parent_lock);
+
+       ret = reiser4_get_parent(&parent_lock, node, ZNODE_WRITE_LOCK);
+       if (ret)
+               return ret;
+
+       assert("zam-934", !znode_above_root(parent_lock.node));
+
+       ret = zload(parent_lock.node);
+       if (ret)
+               goto failed_nozrelse;
+
+       ret = find_child_ptr(parent_lock.node, node, &cut_from);
+       if (ret)
+               goto failed;
+
+       /* decrement child counter and set parent pointer to NULL before
+          deleting the list from parent node because of checks in
+          internal_kill_item_hook (we can delete the last item from the parent
+          node, the parent node is going to be deleted and its c_count should
+          be zero). */
+
+       tree = znode_get_tree(node);
+       write_lock_tree(tree);
+       init_parent_coord(&node->in_parent, NULL);
+       --parent_lock.node->c_count;
+       write_unlock_tree(tree);
+
+       assert("zam-989", item_is_internal(&cut_from));
+
+       /* @node should be deleted after unlocking. */
+       ZF_SET(node, JNODE_HEARD_BANSHEE);
+
+       /* remove a pointer from the parent node to the node being deleted. */
+       coord_dup(&cut_to, &cut_from);
+       /* FIXME: shouldn't this be kill_node_content */
+       ret = cut_node_content(&cut_from, &cut_to, NULL, NULL, NULL);
+       if (ret)
+               /* FIXME(Zam): Should we re-connect the node to its parent if
+                * cut_node fails? */
+               goto failed;
+
+       {
+               reiser4_tree *tree = current_tree;
+               __u64 start_offset = 0, end_offset = 0;
+
+               read_lock_tree(tree);
+               write_lock_dk(tree);
+               if (object) {
+                       /* We use @smallest_removed and the left delimiting of
+                        * the current node for @object->i_blocks, i_bytes
+                        * calculation.  We assume that the items after the
+                        * *@smallest_removed key have been deleted from the
+                        * file body. */
+                       start_offset = get_key_offset(znode_get_ld_key(node));
+                       end_offset = get_key_offset(smallest_removed);
+               }
+
+               assert("zam-1021", znode_is_connected(node));
+               if (node->left)
+                       znode_set_rd_key(node->left, znode_get_rd_key(node));
+
+               *smallest_removed = *znode_get_ld_key(node);
+
+               write_unlock_dk(tree);
+               read_unlock_tree(tree);
+
+               if (object) {
+                       /* we used to perform actions which are to be performed on items on their removal from tree in
+                          special item method - kill_hook. Here for optimization reasons we avoid reading node
+                          containing item we remove and can not call item's kill hook. Instead we call function which
+                          does exactly the same things as tail kill hook in assumption that node we avoid reading
+                          contains only one item and that item is a tail one. */
+                       fake_kill_hook_tail(object, start_offset, end_offset,
+                                           truncate);
+               }
+       }
+      failed:
+       zrelse(parent_lock.node);
+      failed_nozrelse:
+       done_lh(&parent_lock);
+
+       return ret;
+}
+
+static int can_delete(const reiser4_key *key, znode *node)
+{
+       int result;
+
+       read_lock_dk(current_tree);
+       result = keyle(key, znode_get_ld_key(node));
+       read_unlock_dk(current_tree);
+       return result;
+}
+
+/**
+ * This subroutine is not optimal but implementation seems to
+ * be easier).
+ *
+ * @tap: the point deletion process begins from,
+ * @from_key: the beginning of the deleted key range,
+ * @to_key: the end of the deleted key range,
+ * @smallest_removed: the smallest removed key,
+ * @truncate: true if called for file truncate.
+ * @progress: return true if a progress in file items deletions was made,
+ *            @smallest_removed value is actual in that case.
+ *
+ * @return: 0 if success, error code otherwise, -E_REPEAT means that long
+ * reiser4_cut_tree operation was interrupted for allowing atom commit.
+ */
+int
+cut_tree_worker_common(tap_t * tap, const reiser4_key * from_key,
+                      const reiser4_key * to_key,
+                      reiser4_key * smallest_removed, struct inode *object,
+                      int truncate, int *progress)
+{
+       lock_handle next_node_lock;
+       coord_t left_coord;
+       int result;
+
+       assert("zam-931", tap->coord->node != NULL);
+       assert("zam-932", znode_is_write_locked(tap->coord->node));
+
+       *progress = 0;
+       init_lh(&next_node_lock);
+
+       while (1) {
+               znode *node;    /* node from which items are cut */
+               node_plugin *nplug;     /* node plugin for @node */
+
+               node = tap->coord->node;
+
+               /* Move next_node_lock to the next node on the left. */
+               result =
+                   reiser4_get_left_neighbor(&next_node_lock, node,
+                                             ZNODE_WRITE_LOCK,
+                                             GN_CAN_USE_UPPER_LEVELS);
+               if (result != 0 && result != -E_NO_NEIGHBOR)
+                       break;
+               /* Check can we delete the node as a whole. */
+               if (*progress && znode_get_level(node) == LEAF_LEVEL &&
+                   can_delete(from_key, node)) {
+                       result = reiser4_delete_node(node, smallest_removed,
+                                                    object, truncate);
+               } else {
+                       result = reiser4_tap_load(tap);
+                       if (result)
+                               return result;
+
+                       /* Prepare the second (right) point for cut_node() */
+                       if (*progress)
+                               coord_init_last_unit(tap->coord, node);
+
+                       else if (item_plugin_by_coord(tap->coord)->b.lookup ==
+                                NULL)
+                               /* set rightmost unit for the items without lookup method */
+                               tap->coord->unit_pos =
+                                   coord_last_unit_pos(tap->coord);
+
+                       nplug = node->nplug;
+
+                       assert("vs-686", nplug);
+                       assert("vs-687", nplug->lookup);
+
+                       /* left_coord is leftmost unit cut from @node */
+                       result = nplug->lookup(node, from_key,
+                                              FIND_MAX_NOT_MORE_THAN,
+                                              &left_coord);
+
+                       if (IS_CBKERR(result))
+                               break;
+
+                       /* adjust coordinates so that they are set to existing units */
+                       if (coord_set_to_right(&left_coord)
+                           || coord_set_to_left(tap->coord)) {
+                               result = 0;
+                               break;
+                       }
+
+                       if (coord_compare(&left_coord, tap->coord) ==
+                           COORD_CMP_ON_RIGHT) {
+                               /* keys from @from_key to @to_key are not in the tree */
+                               result = 0;
+                               break;
+                       }
+
+                       if (left_coord.item_pos != tap->coord->item_pos) {
+                               /* do not allow to cut more than one item. It is added to solve problem of truncating
+                                  partially converted files. If file is partially converted there may exist a twig node
+                                  containing both internal item or items pointing to leaf nodes with formatting items
+                                  and extent item. We do not want to kill internal items being at twig node here
+                                  because cut_tree_worker assumes killing them from level level */
+                               coord_dup(&left_coord, tap->coord);
+                               assert("vs-1652",
+                                      coord_is_existing_unit(&left_coord));
+                               left_coord.unit_pos = 0;
+                       }
+
+                       /* cut data from one node */
+                       // *smallest_removed = *reiser4_min_key();
+                       result =
+                           kill_node_content(&left_coord, tap->coord, from_key,
+                                             to_key, smallest_removed,
+                                             next_node_lock.node, object,
+                                             truncate);
+                       reiser4_tap_relse(tap);
+               }
+               if (result)
+                       break;
+
+               ++(*progress);
+
+               /* Check whether all items with keys >= from_key were removed
+                * from the tree. */
+               if (keyle(smallest_removed, from_key))
+                       /* result = 0; */
+                       break;
+
+               if (next_node_lock.node == NULL)
+                       break;
+
+               result = reiser4_tap_move(tap, &next_node_lock);
+               done_lh(&next_node_lock);
+               if (result)
+                       break;
+
+               /* Break long reiser4_cut_tree operation (deletion of a large
+                  file) if atom requires commit. */
+               if (*progress > CUT_TREE_MIN_ITERATIONS
+                   && current_atom_should_commit()) {
+                       result = -E_REPEAT;
+                       break;
+               }
+       }
+       done_lh(&next_node_lock);
+       // assert("vs-301", !keyeq(&smallest_removed, reiser4_min_key()));
+       return result;
+}
+
+/* there is a fundamental problem with optimizing deletes: VFS does it
+   one file at a time.  Another problem is that if an item can be
+   anything, then deleting items must be done one at a time.  It just
+   seems clean to writes this to specify a from and a to key, and cut
+   everything between them though.  */
+
+/* use this function with care if deleting more than what is part of a single file. */
+/* do not use this when cutting a single item, it is suboptimal for that */
+
+/* You are encouraged to write plugin specific versions of this.  It
+   cannot be optimal for all plugins because it works item at a time,
+   and some plugins could sometimes work node at a time. Regular files
+   however are not optimizable to work node at a time because of
+   extents needing to free the blocks they point to.
+
+   Optimizations compared to v3 code:
+
+   It does not balance (that task is left to memory pressure code).
+
+   Nodes are deleted only if empty.
+
+   Uses extents.
+
+   Performs read-ahead of formatted nodes whose contents are part of
+   the deletion.
+*/
+
+/**
+ * Delete everything from the reiser4 tree between two keys: @from_key and
+ * @to_key.
+ *
+ * @from_key: the beginning of the deleted key range,
+ * @to_key: the end of the deleted key range,
+ * @smallest_removed: the smallest removed key,
+ * @object: owner of cutting items.
+ * @truncate: true if called for file truncate.
+ * @progress: return true if a progress in file items deletions was made,
+ *            @smallest_removed value is actual in that case.
+ *
+ * @return: 0 if success, error code otherwise, -E_REPEAT means that long cut_tree
+ * operation was interrupted for allowing atom commit .
+ */
+
+int reiser4_cut_tree_object(reiser4_tree * tree, const reiser4_key * from_key,
+                           const reiser4_key * to_key,
+                           reiser4_key * smallest_removed_p,
+                           struct inode *object, int truncate, int *progress)
+{
+       lock_handle lock;
+       int result;
+       tap_t tap;
+       coord_t right_coord;
+       reiser4_key smallest_removed;
+       int (*cut_tree_worker) (tap_t *, const reiser4_key *,
+                               const reiser4_key *, reiser4_key *,
+                               struct inode *, int, int *);
+       STORE_COUNTERS;
+
+       assert("umka-329", tree != NULL);
+       assert("umka-330", from_key != NULL);
+       assert("umka-331", to_key != NULL);
+       assert("zam-936", keyle(from_key, to_key));
+
+       if (smallest_removed_p == NULL)
+               smallest_removed_p = &smallest_removed;
+
+       init_lh(&lock);
+
+       do {
+               /* Find rightmost item to cut away from the tree. */
+               result = reiser4_object_lookup(object, to_key, &right_coord,
+                                              &lock, ZNODE_WRITE_LOCK,
+                                              FIND_MAX_NOT_MORE_THAN,
+                                              TWIG_LEVEL, LEAF_LEVEL,
+                                              CBK_UNIQUE, NULL /*ra_info */);
+               if (result != CBK_COORD_FOUND)
+                       break;
+               if (object == NULL
+                   || inode_file_plugin(object)->cut_tree_worker == NULL)
+                       cut_tree_worker = cut_tree_worker_common;
+               else
+                       cut_tree_worker =
+                           inode_file_plugin(object)->cut_tree_worker;
+               reiser4_tap_init(&tap, &right_coord, &lock, ZNODE_WRITE_LOCK);
+               result =
+                   cut_tree_worker(&tap, from_key, to_key, smallest_removed_p,
+                                   object, truncate, progress);
+               reiser4_tap_done(&tap);
+
+               reiser4_preempt_point();
+
+       } while (0);
+
+       done_lh(&lock);
+
+       if (result) {
+               switch (result) {
+               case -E_NO_NEIGHBOR:
+                       result = 0;
+                       break;
+               case -E_DEADLOCK:
+                       result = -E_REPEAT;
+               case -E_REPEAT:
+               case -ENOMEM:
+               case -ENOENT:
+                       break;
+               default:
+                       warning("nikita-2861", "failure: %i", result);
+               }
+       }
+
+       CHECK_COUNTERS;
+       return result;
+}
+
+/* repeat reiser4_cut_tree_object until everything is deleted.
+ * unlike cut_file_items, it does not end current transaction if -E_REPEAT
+ * is returned by cut_tree_object. */
+int reiser4_cut_tree(reiser4_tree * tree, const reiser4_key * from,
+                    const reiser4_key * to, struct inode *inode, int truncate)
+{
+       int result;
+       int progress;
+
+       do {
+               result = reiser4_cut_tree_object(tree, from, to, NULL,
+                                                inode, truncate, &progress);
+       } while (result == -E_REPEAT);
+
+       return result;
+}
+
+/* finishing reiser4 initialization */
+int reiser4_init_tree(reiser4_tree * tree      /* pointer to structure being
+                                        * initialized */ ,
+             const reiser4_block_nr * root_block       /* address of a root block
+                                                        * on a disk */ ,
+             tree_level height /* height of a tree */ ,
+             node_plugin * nplug /* default node plugin */ )
+{
+       int result;
+
+       assert("nikita-306", tree != NULL);
+       assert("nikita-307", root_block != NULL);
+       assert("nikita-308", height > 0);
+       assert("nikita-309", nplug != NULL);
+       assert("zam-587", tree->super != NULL);
+
+       tree->root_block = *root_block;
+       tree->height = height;
+       tree->estimate_one_insert = calc_estimate_one_insert(height);
+       tree->nplug = nplug;
+
+       tree->znode_epoch = 1ull;
+
+       cbk_cache_init(&tree->cbk_cache);
+
+       result = znodes_tree_init(tree);
+       if (result == 0)
+               result = jnodes_tree_init(tree);
+       if (result == 0) {
+               tree->uber = zget(tree, &UBER_TREE_ADDR, NULL, 0,
+                                 reiser4_ctx_gfp_mask_get());
+               if (IS_ERR(tree->uber)) {
+                       result = PTR_ERR(tree->uber);
+                       tree->uber = NULL;
+               }
+       }
+       return result;
+}
+
+/* release resources associated with @tree */
+void reiser4_done_tree(reiser4_tree * tree /* tree to release */ )
+{
+       if (tree == NULL)
+               return;
+
+       if (tree->uber != NULL) {
+               zput(tree->uber);
+               tree->uber = NULL;
+       }
+       znodes_tree_done(tree);
+       jnodes_tree_done(tree);
+       cbk_cache_done(&tree->cbk_cache);
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree.h linux-2.6.20/fs/reiser4/tree.h
--- linux-2.6.20.orig/fs/reiser4/tree.h 1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree.h      2007-05-06 14:50:43.883033217 +0400
@@ -0,0 +1,577 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Tree operations. See fs/reiser4/tree.c for comments */
+
+#if !defined( __REISER4_TREE_H__ )
+#define __REISER4_TREE_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "plugin/node/node.h"
+#include "plugin/plugin.h"
+#include "znode.h"
+#include "tap.h"
+
+#include <linux/types.h>       /* for __u??  */
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/spinlock.h>
+#include <linux/sched.h>       /* for struct task_struct */
+
+/* fictive block number never actually used */
+extern const reiser4_block_nr UBER_TREE_ADDR;
+
+/* &cbk_cache_slot - entry in a coord cache.
+
+   This is entry in a coord_by_key (cbk) cache, represented by
+   &cbk_cache.
+
+*/
+typedef struct cbk_cache_slot {
+       /* cached node */
+       znode *node;
+       /* linkage to the next cbk cache slot in a LRU order */
+       struct list_head lru;
+} cbk_cache_slot;
+
+/* &cbk_cache - coord cache. This is part of reiser4_tree.
+
+   cbk_cache is supposed to speed up tree lookups by caching results of recent
+   successful lookups (we don't cache negative results as dentry cache
+   does). Cache consists of relatively small number of entries kept in a LRU
+   order. Each entry (&cbk_cache_slot) contains a pointer to znode, from
+   which we can obtain a range of keys that covered by this znode. Before
+   embarking into real tree traversal we scan cbk_cache slot by slot and for
+   each slot check whether key we are looking for is between minimal and
+   maximal keys for node pointed to by this slot. If no match is found, real
+   tree traversal is performed and if result is successful, appropriate entry
+   is inserted into cache, possibly pulling least recently used entry out of
+   it.
+
+   Tree spin lock is used to protect coord cache. If contention for this
+   lock proves to be too high, more finer grained locking can be added.
+
+   Invariants involving parts of this data-type:
+
+      [cbk-cache-invariant]
+*/
+typedef struct cbk_cache {
+       /* serializator */
+       rwlock_t guard;
+       int nr_slots;
+       /* head of LRU list of cache slots */
+       struct list_head lru;
+       /* actual array of slots */
+       cbk_cache_slot *slot;
+} cbk_cache;
+
+/* level_lookup_result - possible outcome of looking up key at some level.
+   This is used by coord_by_key when traversing tree downward. */
+typedef enum {
+       /* continue to the next level */
+       LOOKUP_CONT,
+       /* done. Either required item was found, or we can prove it
+          doesn't exist, or some error occurred. */
+       LOOKUP_DONE,
+       /* restart traversal from the root. Infamous "repetition". */
+       LOOKUP_REST
+} level_lookup_result;
+
+/*    This is representation of internal reiser4 tree where all file-system
+   data and meta-data are stored. This structure is passed to all tree
+   manipulation functions. It's different from the super block because:
+   we don't want to limit ourselves to strictly one to one mapping
+   between super blocks and trees, and, because they are logically
+   different: there are things in a super block that have no relation to
+   the tree (bitmaps, journalling area, mount options, etc.) and there
+   are things in a tree that bear no relation to the super block, like
+   tree of znodes.
+
+   At this time, there is only one tree
+   per filesystem, and this struct is part of the super block.  We only
+   call the super block the super block for historical reasons (most
+   other filesystems call the per filesystem metadata the super block).
+*/
+
+struct reiser4_tree {
+       /* block_nr == 0 is fake znode. Write lock it, while changing
+          tree height. */
+       /* disk address of root node of a tree */
+       reiser4_block_nr root_block;
+
+       /* level of the root node. If this is 1, tree consists of root
+          node only */
+       tree_level height;
+
+       /*
+        * this is cached here avoid calling plugins through function
+        * dereference all the time.
+        */
+       __u64 estimate_one_insert;
+
+       /* cache of recent tree lookup results */
+       cbk_cache cbk_cache;
+
+       /* hash table to look up znodes by block number. */
+       z_hash_table zhash_table;
+       z_hash_table zfake_table;
+       /* hash table to look up jnodes by inode and offset. */
+       j_hash_table jhash_table;
+
+       /* lock protecting:
+          - parent pointers,
+          - sibling pointers,
+          - znode hash table
+          - coord cache
+        */
+       /* NOTE: The "giant" tree lock can be replaced by more spin locks,
+          hoping they will be less contented. We can use one spin lock per one
+          znode hash bucket.  With adding of some code complexity, sibling
+          pointers can be protected by both znode spin locks.  However it looks
+          more SMP scalable we should test this locking change on n-ways (n >
+          4) SMP machines.  Current 4-ways machine test does not show that tree
+          lock is contented and it is a bottleneck (2003.07.25). */
+
+       rwlock_t tree_lock;
+
+       /* lock protecting delimiting keys */
+       rwlock_t dk_lock;
+
+       /* spin lock protecting znode_epoch */
+       spinlock_t epoch_lock;
+       /* version stamp used to mark znode updates. See seal.[ch] for more
+        * information. */
+       __u64 znode_epoch;
+
+       znode *uber;
+       node_plugin *nplug;
+       struct super_block *super;
+       struct {
+               /* carry flags used for insertion of new nodes */
+               __u32 new_node_flags;
+               /* carry flags used for insertion of new extents */
+               __u32 new_extent_flags;
+               /* carry flags used for paste operations */
+               __u32 paste_flags;
+               /* carry flags used for insert operations */
+               __u32 insert_flags;
+       } carry;
+};
+
+extern int reiser4_init_tree(reiser4_tree * tree,
+                            const reiser4_block_nr * root_block,
+                            tree_level height, node_plugin * default_plugin);
+extern void reiser4_done_tree(reiser4_tree * tree);
+
+/* cbk flags: options for coord_by_key() */
+typedef enum {
+       /* coord_by_key() is called for insertion. This is necessary because
+          of extents being located at the twig level. For explanation, see
+          comment just above is_next_item_internal().
+        */
+       CBK_FOR_INSERT = (1 << 0),
+       /* coord_by_key() is called with key that is known to be unique */
+       CBK_UNIQUE = (1 << 1),
+       /* coord_by_key() can trust delimiting keys. This options is not user
+          accessible. coord_by_key() will set it automatically. It will be
+          only cleared by special-case in extents-on-the-twig-level handling
+          where it is necessary to insert item with a key smaller than
+          leftmost key in a node. This is necessary because of extents being
+          located at the twig level. For explanation, see comment just above
+          is_next_item_internal().
+        */
+       CBK_TRUST_DK = (1 << 2),
+       CBK_READA = (1 << 3),   /* original: readahead leaves which contain items of certain file */
+       CBK_READDIR_RA = (1 << 4),      /* readdir: readahead whole directory and all its stat datas */
+       CBK_DKSET = (1 << 5),
+       CBK_EXTENDED_COORD = (1 << 6),  /* coord_t is actually */
+       CBK_IN_CACHE = (1 << 7),        /* node is already in cache */
+       CBK_USE_CRABLOCK = (1 << 8)     /* use crab_lock in stead of long term
+                                        * lock */
+} cbk_flags;
+
+/* insertion outcome. IBK = insert by key */
+typedef enum {
+       IBK_INSERT_OK = 0,
+       IBK_ALREADY_EXISTS = -EEXIST,
+       IBK_IO_ERROR = -EIO,
+       IBK_NO_SPACE = -E_NODE_FULL,
+       IBK_OOM = -ENOMEM
+} insert_result;
+
+#define IS_CBKERR(err) ((err) != CBK_COORD_FOUND && (err) != CBK_COORD_NOTFOUND)
+
+typedef int (*tree_iterate_actor_t) (reiser4_tree * tree, coord_t * coord,
+                                    lock_handle * lh, void *arg);
+extern int reiser4_iterate_tree(reiser4_tree * tree, coord_t * coord,
+                               lock_handle * lh,
+                               tree_iterate_actor_t actor, void *arg,
+                               znode_lock_mode mode, int through_units_p);
+extern int get_uber_znode(reiser4_tree * tree, znode_lock_mode mode,
+                         znode_lock_request pri, lock_handle * lh);
+
+/* return node plugin of @node */
+static inline node_plugin *node_plugin_by_node(const znode *
+                                              node /* node to query */ )
+{
+       assert("vs-213", node != NULL);
+       assert("vs-214", znode_is_loaded(node));
+
+       return node->nplug;
+}
+
+/* number of items in @node */
+static inline pos_in_node_t node_num_items(const znode * node)
+{
+       assert("nikita-2754", znode_is_loaded(node));
+       assert("nikita-2468",
+              node_plugin_by_node(node)->num_of_items(node) == node->nr_items);
+
+       return node->nr_items;
+}
+
+/* Return the number of items at the present node.  Asserts coord->node !=
+   NULL. */
+static inline unsigned coord_num_items(const coord_t * coord)
+{
+       assert("jmacd-9805", coord->node != NULL);
+
+       return node_num_items(coord->node);
+}
+
+/* true if @node is empty */
+static inline int node_is_empty(const znode * node)
+{
+       return node_num_items(node) == 0;
+}
+
+typedef enum {
+       SHIFTED_SOMETHING = 0,
+       SHIFT_NO_SPACE = -E_NODE_FULL,
+       SHIFT_IO_ERROR = -EIO,
+       SHIFT_OOM = -ENOMEM,
+} shift_result;
+
+extern node_plugin *node_plugin_by_coord(const coord_t * coord);
+extern int is_coord_in_node(const coord_t * coord);
+extern int key_in_node(const reiser4_key *, const coord_t *);
+extern void coord_item_move_to(coord_t * coord, int items);
+extern void coord_unit_move_to(coord_t * coord, int units);
+
+/* there are two types of repetitive accesses (ra): intra-syscall
+   (local) and inter-syscall (global). Local ra is used when
+   during single syscall we add/delete several items and units in the
+   same place in a tree. Note that plan-A fragments local ra by
+   separating stat-data and file body in key-space. Global ra is
+   used when user does repetitive modifications in the same place in a
+   tree.
+
+   Our ra implementation serves following purposes:
+    1 it affects balancing decisions so that next operation in a row
+      can be performed faster;
+    2 it affects lower-level read-ahead in page-cache;
+    3 it allows to avoid unnecessary lookups by maintaining some state
+      across several operations (this is only for local ra);
+    4 it leaves room for lazy-micro-balancing: when we start a sequence of
+      operations they are performed without actually doing any intra-node
+      shifts, until we finish sequence or scope of sequence leaves
+      current node, only then we really pack node (local ra only).
+*/
+
+/* another thing that can be useful is to keep per-tree and/or
+   per-process cache of recent lookups. This cache can be organised as a
+   list of block numbers of formatted nodes sorted by starting key in
+   this node. Balancings should invalidate appropriate parts of this
+   cache.
+*/
+
+lookup_result coord_by_key(reiser4_tree * tree, const reiser4_key * key,
+                          coord_t * coord, lock_handle * handle,
+                          znode_lock_mode lock, lookup_bias bias,
+                          tree_level lock_level, tree_level stop_level,
+                          __u32 flags, ra_info_t *);
+
+lookup_result reiser4_object_lookup(struct inode *object,
+                                   const reiser4_key * key,
+                                   coord_t * coord,
+                                   lock_handle * lh,
+                                   znode_lock_mode lock_mode,
+                                   lookup_bias bias,
+                                   tree_level lock_level,
+                                   tree_level stop_level,
+                                   __u32 flags, ra_info_t * info);
+
+insert_result insert_by_key(reiser4_tree * tree, const reiser4_key * key,
+                           reiser4_item_data * data, coord_t * coord,
+                           lock_handle * lh,
+                           tree_level stop_level, __u32 flags);
+insert_result insert_by_coord(coord_t * coord,
+                             reiser4_item_data * data, const reiser4_key * key,
+                             lock_handle * lh, __u32);
+insert_result insert_extent_by_coord(coord_t * coord,
+                                    reiser4_item_data * data,
+                                    const reiser4_key * key, lock_handle * lh);
+int cut_node_content(coord_t * from, coord_t * to, const reiser4_key * from_key,
+                    const reiser4_key * to_key,
+                    reiser4_key * smallest_removed);
+int kill_node_content(coord_t * from, coord_t * to,
+                     const reiser4_key * from_key, const reiser4_key * to_key,
+                     reiser4_key * smallest_removed,
+                     znode * locked_left_neighbor, struct inode *inode,
+                     int truncate);
+
+int reiser4_resize_item(coord_t * coord, reiser4_item_data * data,
+                       reiser4_key * key, lock_handle * lh, cop_insert_flag);
+int insert_into_item(coord_t * coord, lock_handle * lh, const reiser4_key * key,
+                    reiser4_item_data * data, unsigned);
+int reiser4_insert_flow(coord_t * coord, lock_handle * lh, flow_t * f);
+int find_new_child_ptr(znode * parent, znode * child, znode * left,
+                      coord_t * result);
+
+int shift_right_of_but_excluding_insert_coord(coord_t * insert_coord);
+int shift_left_of_and_including_insert_coord(coord_t * insert_coord);
+
+void fake_kill_hook_tail(struct inode *, loff_t start, loff_t end, int);
+
+extern int cut_tree_worker_common(tap_t *, const reiser4_key *,
+                                 const reiser4_key *, reiser4_key *,
+                                 struct inode *, int, int *);
+extern int reiser4_cut_tree_object(reiser4_tree *, const reiser4_key *,
+                                  const reiser4_key *, reiser4_key *,
+                                  struct inode *, int, int *);
+extern int reiser4_cut_tree(reiser4_tree * tree, const reiser4_key * from,
+                           const reiser4_key * to, struct inode *, int);
+
+extern int reiser4_delete_node(znode *, reiser4_key *, struct inode *, int);
+extern int check_tree_pointer(const coord_t * pointer, const znode * child);
+extern int find_new_child_ptr(znode * parent, znode * child UNUSED_ARG,
+                             znode * left, coord_t * result);
+extern int find_child_ptr(znode * parent, znode * child, coord_t * result);
+extern int set_child_delimiting_keys(znode * parent, const coord_t * in_parent,
+                                    znode * child);
+extern znode *child_znode(const coord_t * in_parent, znode * parent,
+                         int incore_p, int setup_dkeys_p);
+
+extern int cbk_cache_init(cbk_cache * cache);
+extern void cbk_cache_done(cbk_cache * cache);
+extern void cbk_cache_invalidate(const znode * node, reiser4_tree * tree);
+
+extern char *sprint_address(const reiser4_block_nr * block);
+
+#if REISER4_DEBUG
+extern void print_coord_content(const char *prefix, coord_t * p);
+extern void reiser4_print_address(const char *prefix,
+                       const reiser4_block_nr * block);
+extern void print_tree_rec(const char *prefix, reiser4_tree * tree,
+                          __u32 flags);
+extern void check_dkeys(znode *node);
+#else
+#define print_coord_content(p, c) noop
+#define reiser4_print_address(p, b) noop
+#endif
+
+extern void forget_znode(lock_handle * handle);
+extern int deallocate_znode(znode * node);
+
+extern int is_disk_addr_unallocated(const reiser4_block_nr * addr);
+
+/* struct used internally to pack all numerous arguments of tree lookup.
+    Used to avoid passing a lot of arguments to helper functions. */
+typedef struct cbk_handle {
+       /* tree we are in */
+       reiser4_tree *tree;
+       /* key we are going after */
+       const reiser4_key *key;
+       /* coord we will store result in */
+       coord_t *coord;
+       /* type of lock to take on target node */
+       znode_lock_mode lock_mode;
+       /* lookup bias. See comments at the declaration of lookup_bias */
+       lookup_bias bias;
+       /* lock level: level starting from which tree traversal starts taking
+        * write locks. */
+       tree_level lock_level;
+       /* level where search will stop. Either item will be found between
+          lock_level and stop_level, or CBK_COORD_NOTFOUND will be
+          returned.
+        */
+       tree_level stop_level;
+       /* level we are currently at */
+       tree_level level;
+       /* block number of @active node. Tree traversal operates on two
+          nodes: active and parent.  */
+       reiser4_block_nr block;
+       /* put here error message to be printed by caller */
+       const char *error;
+       /* result passed back to caller */
+       lookup_result result;
+       /* lock handles for active and parent */
+       lock_handle *parent_lh;
+       lock_handle *active_lh;
+       reiser4_key ld_key;
+       reiser4_key rd_key;
+       /* flags, passed to the cbk routine. Bits of this bitmask are defined
+          in tree.h:cbk_flags enum. */
+       __u32 flags;
+       ra_info_t *ra_info;
+       struct inode *object;
+} cbk_handle;
+
+extern znode_lock_mode cbk_lock_mode(tree_level level, cbk_handle * h);
+
+/* eottl.c */
+extern int handle_eottl(cbk_handle *h, int *outcome);
+
+int lookup_multikey(cbk_handle * handle, int nr_keys);
+int lookup_couple(reiser4_tree * tree,
+                 const reiser4_key * key1, const reiser4_key * key2,
+                 coord_t * coord1, coord_t * coord2,
+                 lock_handle * lh1, lock_handle * lh2,
+                 znode_lock_mode lock_mode, lookup_bias bias,
+                 tree_level lock_level, tree_level stop_level, __u32 flags,
+                 int *result1, int *result2);
+
+static inline void read_lock_tree(reiser4_tree *tree)
+{
+       /* check that tree is not locked */
+       assert("", (LOCK_CNT_NIL(rw_locked_tree) &&
+                   LOCK_CNT_NIL(read_locked_tree) &&
+                   LOCK_CNT_NIL(write_locked_tree)));
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(spin_locked_stack)));
+
+       read_lock(&(tree->tree_lock));
+
+       LOCK_CNT_INC(read_locked_tree);
+       LOCK_CNT_INC(rw_locked_tree);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void read_unlock_tree(reiser4_tree *tree)
+{
+       assert("nikita-1375", LOCK_CNT_GTZ(read_locked_tree));
+       assert("nikita-1376", LOCK_CNT_GTZ(rw_locked_tree));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(read_locked_tree);
+       LOCK_CNT_DEC(rw_locked_tree);
+       LOCK_CNT_DEC(spin_locked);
+
+       read_unlock(&(tree->tree_lock));
+}
+
+static inline void write_lock_tree(reiser4_tree *tree)
+{
+       /* check that tree is not locked */
+       assert("", (LOCK_CNT_NIL(rw_locked_tree) &&
+                   LOCK_CNT_NIL(read_locked_tree) &&
+                   LOCK_CNT_NIL(write_locked_tree)));
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(spin_locked_stack)));
+
+       write_lock(&(tree->tree_lock));
+
+       LOCK_CNT_INC(write_locked_tree);
+       LOCK_CNT_INC(rw_locked_tree);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void write_unlock_tree(reiser4_tree *tree)
+{
+       assert("nikita-1375", LOCK_CNT_GTZ(write_locked_tree));
+       assert("nikita-1376", LOCK_CNT_GTZ(rw_locked_tree));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(write_locked_tree);
+       LOCK_CNT_DEC(rw_locked_tree);
+       LOCK_CNT_DEC(spin_locked);
+
+       write_unlock(&(tree->tree_lock));
+}
+
+static inline void read_lock_dk(reiser4_tree *tree)
+{
+       /* check that dk is not locked */
+       assert("", (LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(read_locked_dk) &&
+                   LOCK_CNT_NIL(write_locked_dk)));
+       /* check that spinlocks of lower priorities are not held */
+       assert("", LOCK_CNT_NIL(spin_locked_stack));
+
+       read_lock(&((tree)->dk_lock));
+
+       LOCK_CNT_INC(read_locked_dk);
+       LOCK_CNT_INC(rw_locked_dk);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void read_unlock_dk(reiser4_tree *tree)
+{
+       assert("nikita-1375", LOCK_CNT_GTZ(read_locked_dk));
+       assert("nikita-1376", LOCK_CNT_GTZ(rw_locked_dk));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(read_locked_dk);
+       LOCK_CNT_DEC(rw_locked_dk);
+       LOCK_CNT_DEC(spin_locked);
+
+       read_unlock(&(tree->dk_lock));
+}
+
+static inline void write_lock_dk(reiser4_tree *tree)
+{
+       /* check that dk is not locked */
+       assert("", (LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(read_locked_dk) &&
+                   LOCK_CNT_NIL(write_locked_dk)));
+       /* check that spinlocks of lower priorities are not held */
+       assert("", LOCK_CNT_NIL(spin_locked_stack));
+
+       write_lock(&((tree)->dk_lock));
+
+       LOCK_CNT_INC(write_locked_dk);
+       LOCK_CNT_INC(rw_locked_dk);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void write_unlock_dk(reiser4_tree *tree)
+{
+       assert("nikita-1375", LOCK_CNT_GTZ(write_locked_dk));
+       assert("nikita-1376", LOCK_CNT_GTZ(rw_locked_dk));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(write_locked_dk);
+       LOCK_CNT_DEC(rw_locked_dk);
+       LOCK_CNT_DEC(spin_locked);
+
+       write_unlock(&(tree->dk_lock));
+}
+
+/* estimate api. Implementation is in estimate.c */
+reiser4_block_nr estimate_one_insert_item(reiser4_tree *);
+reiser4_block_nr estimate_one_insert_into_item(reiser4_tree *);
+reiser4_block_nr estimate_insert_flow(tree_level);
+reiser4_block_nr estimate_one_item_removal(reiser4_tree *);
+reiser4_block_nr calc_estimate_one_insert(tree_level);
+reiser4_block_nr estimate_dirty_cluster(struct inode *);
+reiser4_block_nr estimate_insert_cluster(struct inode *);
+reiser4_block_nr estimate_update_cluster(struct inode *);
+
+/* __REISER4_TREE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree_mod.c linux-2.6.20/fs/reiser4/tree_mod.c
--- linux-2.6.20.orig/fs/reiser4/tree_mod.c     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree_mod.c  2007-05-06 14:50:43.887034467 +0400
@@ -0,0 +1,386 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/*
+ * Functions to add/delete new nodes to/from the tree.
+ *
+ * Functions from this file are used by carry (see carry*) to handle:
+ *
+ *     . insertion of new formatted node into tree
+ *
+ *     . addition of new tree root, increasing tree height
+ *
+ *     . removing tree root, decreasing tree height
+ *
+ */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/plugin.h"
+#include "jnode.h"
+#include "znode.h"
+#include "tree_mod.h"
+#include "block_alloc.h"
+#include "tree_walk.h"
+#include "tree.h"
+#include "super.h"
+
+#include <linux/err.h>
+
+static int add_child_ptr(znode * parent, znode * child);
+/* warning only issued if error is not -E_REPEAT */
+#define ewarning( error, ... )                 \
+       if( ( error ) != -E_REPEAT )            \
+               warning( __VA_ARGS__ )
+
+/* allocate new node on the @level and immediately on the right of @brother. */
+znode * reiser4_new_node(znode * brother /* existing left neighbor
+                                         *  of new node */,
+                        tree_level level /* tree level at which new node is to
+                                          * be allocated */)
+{
+       znode *result;
+       int retcode;
+       reiser4_block_nr blocknr;
+
+       assert("nikita-930", brother != NULL);
+       assert("umka-264", level < REAL_MAX_ZTREE_HEIGHT);
+
+       retcode = assign_fake_blocknr_formatted(&blocknr);
+       if (retcode == 0) {
+               result =
+                   zget(znode_get_tree(brother), &blocknr, NULL, level,
+                        reiser4_ctx_gfp_mask_get());
+               if (IS_ERR(result)) {
+                       ewarning(PTR_ERR(result), "nikita-929",
+                                "Cannot allocate znode for carry: %li",
+                                PTR_ERR(result));
+                       return result;
+               }
+               /* cheap test, can be executed even when debugging is off */
+               if (!znode_just_created(result)) {
+                       warning("nikita-2213",
+                               "Allocated already existing block: %llu",
+                               (unsigned long long)blocknr);
+                       zput(result);
+                       return ERR_PTR(RETERR(-EIO));
+               }
+
+               assert("nikita-931", result != NULL);
+               result->nplug = znode_get_tree(brother)->nplug;
+               assert("nikita-933", result->nplug != NULL);
+
+               retcode = zinit_new(result, reiser4_ctx_gfp_mask_get());
+               if (retcode == 0) {
+                       ZF_SET(result, JNODE_CREATED);
+                       zrelse(result);
+               } else {
+                       zput(result);
+                       result = ERR_PTR(retcode);
+               }
+       } else {
+               /* failure to allocate new node during balancing.
+                  This should never happen. Ever. Returning -E_REPEAT
+                  is not viable solution, because "out of disk space"
+                  is not transient error that will go away by itself.
+                */
+               ewarning(retcode, "nikita-928",
+                        "Cannot allocate block for carry: %i", retcode);
+               result = ERR_PTR(retcode);
+       }
+       assert("nikita-1071", result != NULL);
+       return result;
+}
+
+/* allocate new root and add it to the tree
+
+   This helper function is called by add_new_root().
+
+*/
+znode *reiser4_add_tree_root(znode * old_root /* existing tree root */ ,
+                    znode * fake /* "fake" znode */ )
+{
+       reiser4_tree *tree = znode_get_tree(old_root);
+       znode *new_root = NULL; /* to shut gcc up */
+       int result;
+
+       assert("nikita-1069", old_root != NULL);
+       assert("umka-262", fake != NULL);
+       assert("umka-263", tree != NULL);
+
+       /* "fake" znode---one always hanging just above current root. This
+          node is locked when new root is created or existing root is
+          deleted. Downward tree traversal takes lock on it before taking
+          lock on a root node. This avoids race conditions with root
+          manipulations.
+
+        */
+       assert("nikita-1348", znode_above_root(fake));
+       assert("nikita-1211", znode_is_root(old_root));
+
+       result = 0;
+       if (tree->height >= REAL_MAX_ZTREE_HEIGHT) {
+               warning("nikita-1344", "Tree is too tall: %i", tree->height);
+               /* ext2 returns -ENOSPC when it runs out of free inodes with a
+                  following comment (fs/ext2/ialloc.c:441): Is it really
+                  ENOSPC?
+
+                  -EXFULL? -EINVAL?
+                */
+               result = RETERR(-ENOSPC);
+       } else {
+               /* Allocate block for new root. It's not that
+                  important where it will be allocated, as root is
+                  almost always in memory. Moreover, allocate on
+                  flush can be going here.
+                */
+               assert("nikita-1448", znode_is_root(old_root));
+               new_root = reiser4_new_node(fake, tree->height + 1);
+               if (!IS_ERR(new_root) && (result = zload(new_root)) == 0) {
+                       lock_handle rlh;
+
+                       init_lh(&rlh);
+                       result =
+                           longterm_lock_znode(&rlh, new_root,
+                                               ZNODE_WRITE_LOCK,
+                                               ZNODE_LOCK_LOPRI);
+                       if (result == 0) {
+                               parent_coord_t *in_parent;
+
+                               znode_make_dirty(fake);
+
+                               /* new root is a child of "fake" node */
+                               write_lock_tree(tree);
+
+                               ++tree->height;
+
+                               /* recalculate max balance overhead */
+                               tree->estimate_one_insert =
+                                   estimate_one_insert_item(tree);
+
+                               tree->root_block = *znode_get_block(new_root);
+                               in_parent = &new_root->in_parent;
+                               init_parent_coord(in_parent, fake);
+                               /* manually insert new root into sibling
+                                * list. With this all nodes involved into
+                                * balancing are connected after balancing is
+                                * done---useful invariant to check. */
+                               sibling_list_insert_nolock(new_root, NULL);
+                               write_unlock_tree(tree);
+
+                               /* insert into new root pointer to the
+                                  @old_root. */
+                               assert("nikita-1110",
+                                      WITH_DATA(new_root,
+                                                node_is_empty(new_root)));
+                               write_lock_dk(tree);
+                               znode_set_ld_key(new_root, reiser4_min_key());
+                               znode_set_rd_key(new_root, reiser4_max_key());
+                               write_unlock_dk(tree);
+                               if (REISER4_DEBUG) {
+                                       ZF_CLR(old_root, JNODE_LEFT_CONNECTED);
+                                       ZF_CLR(old_root, JNODE_RIGHT_CONNECTED);
+                                       ZF_SET(old_root, JNODE_ORPHAN);
+                               }
+                               result = add_child_ptr(new_root, old_root);
+                               done_lh(&rlh);
+                       }
+                       zrelse(new_root);
+               }
+       }
+       if (result != 0)
+               new_root = ERR_PTR(result);
+       return new_root;
+}
+
+/* build &reiser4_item_data for inserting child pointer
+
+   Build &reiser4_item_data that can be later used to insert pointer to @child
+   in its parent.
+
+*/
+void build_child_ptr_data(znode * child        /* node pointer to which will be
+                                        * inserted */ ,
+                         reiser4_item_data * data /* where to store result */ )
+{
+       assert("nikita-1116", child != NULL);
+       assert("nikita-1117", data != NULL);
+
+       /*
+        * NOTE: use address of child's blocknr as address of data to be
+        * inserted. As result of this data gets into on-disk structure in cpu
+        * byte order. internal's create_hook converts it to little endian byte
+        * order.
+        */
+       data->data = (char *)znode_get_block(child);
+       /* data -> data is kernel space */
+       data->user = 0;
+       data->length = sizeof(reiser4_block_nr);
+       /* FIXME-VS: hardcoded internal item? */
+
+       /* AUDIT: Is it possible that "item_plugin_by_id" may find nothing? */
+       data->iplug = item_plugin_by_id(NODE_POINTER_ID);
+}
+
+/* add pointer to @child into empty @parent.
+
+   This is used when pointer to old root is inserted into new root which is
+   empty.
+*/
+static int add_child_ptr(znode * parent, znode * child)
+{
+       coord_t coord;
+       reiser4_item_data data;
+       int result;
+       reiser4_key key;
+
+       assert("nikita-1111", parent != NULL);
+       assert("nikita-1112", child != NULL);
+       assert("nikita-1115",
+              znode_get_level(parent) == znode_get_level(child) + 1);
+
+       result = zload(parent);
+       if (result != 0)
+               return result;
+       assert("nikita-1113", node_is_empty(parent));
+       coord_init_first_unit(&coord, parent);
+
+       build_child_ptr_data(child, &data);
+       data.arg = NULL;
+
+       read_lock_dk(znode_get_tree(parent));
+       key = *znode_get_ld_key(child);
+       read_unlock_dk(znode_get_tree(parent));
+
+       result = node_plugin_by_node(parent)->create_item(&coord, &key, &data,
+                                                         NULL);
+       znode_make_dirty(parent);
+       zrelse(parent);
+       return result;
+}
+
+/* actually remove tree root */
+static int reiser4_kill_root(reiser4_tree * tree /* tree from which root is
+                                                 * being removed */,
+                            znode * old_root /* root node that is being
+                                              * removed */ ,
+                            znode * new_root   /* new root---sole child of
+                                                * @old_root */,
+                    const reiser4_block_nr * new_root_blk /* disk address of
+                                                           * @new_root */)
+{
+       znode *uber;
+       int result;
+       lock_handle handle_for_uber;
+
+       assert("umka-265", tree != NULL);
+       assert("nikita-1198", new_root != NULL);
+       assert("nikita-1199",
+              znode_get_level(new_root) + 1 == znode_get_level(old_root));
+
+       assert("nikita-1201", znode_is_write_locked(old_root));
+
+       assert("nikita-1203",
+              disk_addr_eq(new_root_blk, znode_get_block(new_root)));
+
+       init_lh(&handle_for_uber);
+       /* obtain and lock "fake" znode protecting changes in tree height. */
+       result = get_uber_znode(tree, ZNODE_WRITE_LOCK, ZNODE_LOCK_HIPRI,
+                               &handle_for_uber);
+       if (result == 0) {
+               uber = handle_for_uber.node;
+
+               znode_make_dirty(uber);
+
+               /* don't take long term lock a @new_root. Take spinlock. */
+
+               write_lock_tree(tree);
+
+               tree->root_block = *new_root_blk;
+               --tree->height;
+
+               /* recalculate max balance overhead */
+               tree->estimate_one_insert = estimate_one_insert_item(tree);
+
+               assert("nikita-1202",
+                      tree->height == znode_get_level(new_root));
+
+               /* new root is child on "fake" node */
+               init_parent_coord(&new_root->in_parent, uber);
+               ++uber->c_count;
+
+               /* sibling_list_insert_nolock(new_root, NULL); */
+               write_unlock_tree(tree);
+
+               /* reinitialise old root. */
+               result = node_plugin_by_node(old_root)->init(old_root);
+               znode_make_dirty(old_root);
+               if (result == 0) {
+                       assert("nikita-1279", node_is_empty(old_root));
+                       ZF_SET(old_root, JNODE_HEARD_BANSHEE);
+                       old_root->c_count = 0;
+               }
+       }
+       done_lh(&handle_for_uber);
+
+       return result;
+}
+
+/* remove tree root
+
+   This function removes tree root, decreasing tree height by one.  Tree root
+   and its only child (that is going to become new tree root) are write locked
+   at the entry.
+
+   To remove tree root we need to take lock on special "fake" znode that
+   protects changes of tree height. See comments in reiser4_add_tree_root() for
+   more on this.
+
+   Also parent pointers have to be updated in
+   old and new root. To simplify code, function is split into two parts: outer
+   reiser4_kill_tree_root() collects all necessary arguments and calls
+   reiser4_kill_root() to do the actual job.
+
+*/
+int reiser4_kill_tree_root(znode * old_root /* tree root that we are
+                                              removing*/)
+{
+       int result;
+       coord_t down_link;
+       znode *new_root;
+       reiser4_tree *tree;
+
+       assert("umka-266", current_tree != NULL);
+       assert("nikita-1194", old_root != NULL);
+       assert("nikita-1196", znode_is_root(old_root));
+       assert("nikita-1200", node_num_items(old_root) == 1);
+       assert("nikita-1401", znode_is_write_locked(old_root));
+
+       coord_init_first_unit(&down_link, old_root);
+
+       tree = znode_get_tree(old_root);
+       new_root = child_znode(&down_link, old_root, 0, 1);
+       if (!IS_ERR(new_root)) {
+               result =
+                       reiser4_kill_root(tree, old_root, new_root,
+                                         znode_get_block(new_root));
+               zput(new_root);
+       } else
+               result = PTR_ERR(new_root);
+
+       return result;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree_mod.h linux-2.6.20/fs/reiser4/tree_mod.h
--- linux-2.6.20.orig/fs/reiser4/tree_mod.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree_mod.h  2007-05-06 14:50:43.887034467 +0400
@@ -0,0 +1,29 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Functions to add/delete new nodes to/from the tree. See tree_mod.c for
+ * comments. */
+
+#if !defined( __REISER4_TREE_MOD_H__ )
+#define __REISER4_TREE_MOD_H__
+
+#include "forward.h"
+
+znode *reiser4_new_node(znode * brother, tree_level level);
+znode *reiser4_add_tree_root(znode * old_root, znode * fake);
+int reiser4_kill_tree_root(znode * old_root);
+void build_child_ptr_data(znode * child, reiser4_item_data * data);
+
+/* __REISER4_TREE_MOD_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree_walk.c linux-2.6.20/fs/reiser4/tree_walk.c
--- linux-2.6.20.orig/fs/reiser4/tree_walk.c    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree_walk.c 2007-05-06 14:50:43.887034467 +0400
@@ -0,0 +1,927 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Routines and macros to:
+
+   get_left_neighbor()
+
+   get_right_neighbor()
+
+   get_parent()
+
+   get_first_child()
+
+   get_last_child()
+
+   various routines to walk the whole tree and do things to it like
+   repack it, or move it to tertiary storage.  Please make them as
+   generic as is reasonable.
+
+*/
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "jnode.h"
+#include "znode.h"
+#include "tree_walk.h"
+#include "tree.h"
+#include "super.h"
+
+/* These macros are used internally in tree_walk.c in attempt to make
+   lock_neighbor() code usable to build lock_parent(), lock_right_neighbor,
+   lock_left_neighbor */
+#define GET_NODE_BY_PTR_OFFSET(node, off) (*(znode**)(((unsigned long)(node)) + (off)))
+#define FIELD_OFFSET(name)  offsetof(znode, name)
+#define PARENT_PTR_OFFSET FIELD_OFFSET(in_parent.node)
+#define LEFT_PTR_OFFSET   FIELD_OFFSET(left)
+#define RIGHT_PTR_OFFSET  FIELD_OFFSET(right)
+
+/* This is the generic procedure to get and lock `generic' neighbor (left or
+    right neighbor or parent). It implements common algorithm for all cases of
+    getting lock on neighbor node, only znode structure field is different in
+    each case. This is parameterized by ptr_offset argument, which is byte
+    offset for the pointer to the desired neighbor within the current node's
+    znode structure. This function should be called with the tree lock held */
+static int lock_neighbor(
+                               /* resulting lock handle */
+                               lock_handle * result,
+                               /* znode to lock */
+                               znode * node,
+                               /* pointer to neighbor (or parent) znode field offset, in bytes from
+                                  the base address of znode structure  */
+                               int ptr_offset,
+                               /* lock mode for longterm_lock_znode call */
+                               znode_lock_mode mode,
+                               /* lock request for longterm_lock_znode call */
+                               znode_lock_request req,
+                               /* GN_* flags */
+                               int flags, int rlocked)
+{
+       reiser4_tree *tree = znode_get_tree(node);
+       znode *neighbor;
+       int ret;
+
+       assert("umka-236", node != NULL);
+       assert("umka-237", tree != NULL);
+       assert_rw_locked(&(tree->tree_lock));
+
+       if (flags & GN_TRY_LOCK)
+               req |= ZNODE_LOCK_NONBLOCK;
+       if (flags & GN_SAME_ATOM)
+               req |= ZNODE_LOCK_DONT_FUSE;
+
+       /* get neighbor's address by using of sibling link, quit while loop
+          (and return) if link is not available. */
+       while (1) {
+               neighbor = GET_NODE_BY_PTR_OFFSET(node, ptr_offset);
+
+               /* return -E_NO_NEIGHBOR if parent or side pointer is NULL or if
+                * node pointed by it is not connected.
+                *
+                * However, GN_ALLOW_NOT_CONNECTED option masks "connected"
+                * check and allows passing reference to not connected znode to
+                * subsequent longterm_lock_znode() call.  This kills possible
+                * busy loop if we are trying to get longterm lock on locked but
+                * not yet connected parent node. */
+               if (neighbor == NULL || !((flags & GN_ALLOW_NOT_CONNECTED)
+                                         || znode_is_connected(neighbor))) {
+                       return RETERR(-E_NO_NEIGHBOR);
+               }
+
+               /* protect it from deletion. */
+               zref(neighbor);
+
+               rlocked ? read_unlock_tree(tree) : write_unlock_tree(tree);
+
+               ret = longterm_lock_znode(result, neighbor, mode, req);
+
+               /* The lock handle obtains its own reference, release the one from above. */
+               zput(neighbor);
+
+               rlocked ? read_lock_tree(tree) : write_lock_tree(tree);
+
+               /* restart if node we got reference to is being
+                  invalidated. we should not get reference to this node
+                  again. */
+               if (ret == -EINVAL)
+                       continue;
+               if (ret)
+                       return ret;
+
+               /* check if neighbor link still points to just locked znode;
+                  the link could have been changed while the process slept. */
+               if (neighbor == GET_NODE_BY_PTR_OFFSET(node, ptr_offset))
+                       return 0;
+
+               /* znode was locked by mistake; unlock it and restart locking
+                  process from beginning. */
+               rlocked ? read_unlock_tree(tree) : write_unlock_tree(tree);
+               longterm_unlock_znode(result);
+               rlocked ? read_lock_tree(tree) : write_lock_tree(tree);
+       }
+}
+
+/* get parent node with longterm lock, accepts GN* flags. */
+int reiser4_get_parent_flags(lock_handle * lh /* resulting lock handle */ ,
+                            znode * node /* child node */ ,
+                            znode_lock_mode mode
+                            /* type of lock: read or write */ ,
+                            int flags /* GN_* flags */ )
+{
+       int result;
+
+       read_lock_tree(znode_get_tree(node));
+       result = lock_neighbor(lh, node, PARENT_PTR_OFFSET, mode,
+                              ZNODE_LOCK_HIPRI, flags, 1);
+       read_unlock_tree(znode_get_tree(node));
+       return result;
+}
+
+/* wrapper function to lock right or left neighbor depending on GN_GO_LEFT
+   bit in @flags parameter  */
+/* Audited by: umka (2002.06.14) */
+static inline int
+lock_side_neighbor(lock_handle * result,
+                  znode * node, znode_lock_mode mode, int flags, int rlocked)
+{
+       int ret;
+       int ptr_offset;
+       znode_lock_request req;
+
+       if (flags & GN_GO_LEFT) {
+               ptr_offset = LEFT_PTR_OFFSET;
+               req = ZNODE_LOCK_LOPRI;
+       } else {
+               ptr_offset = RIGHT_PTR_OFFSET;
+               req = ZNODE_LOCK_HIPRI;
+       }
+
+       ret =
+           lock_neighbor(result, node, ptr_offset, mode, req, flags, rlocked);
+
+       if (ret == -E_NO_NEIGHBOR)      /* if we walk left or right -E_NO_NEIGHBOR does not
+                                        * guarantee that neighbor is absent in the
+                                        * tree; in this case we return -ENOENT --
+                                        * means neighbor at least not found in
+                                        * cache */
+               return RETERR(-ENOENT);
+
+       return ret;
+}
+
+#if REISER4_DEBUG
+
+int check_sibling_list(znode * node)
+{
+       znode *scan;
+       znode *next;
+
+       assert("nikita-3283", LOCK_CNT_GTZ(write_locked_tree));
+
+       if (node == NULL)
+               return 1;
+
+       if (ZF_ISSET(node, JNODE_RIP))
+               return 1;
+
+       assert("nikita-3270", node != NULL);
+       assert_rw_write_locked(&(znode_get_tree(node)->tree_lock));
+
+       for (scan = node; znode_is_left_connected(scan); scan = next) {
+               next = scan->left;
+               if (next != NULL && !ZF_ISSET(next, JNODE_RIP)) {
+                       assert("nikita-3271", znode_is_right_connected(next));
+                       assert("nikita-3272", next->right == scan);
+               } else
+                       break;
+       }
+       for (scan = node; znode_is_right_connected(scan); scan = next) {
+               next = scan->right;
+               if (next != NULL && !ZF_ISSET(next, JNODE_RIP)) {
+                       assert("nikita-3273", znode_is_left_connected(next));
+                       assert("nikita-3274", next->left == scan);
+               } else
+                       break;
+       }
+       return 1;
+}
+
+#endif
+
+/* Znode sibling pointers maintenence. */
+
+/* Znode sibling pointers are established between any neighbored nodes which are
+   in cache.  There are two znode state bits (JNODE_LEFT_CONNECTED,
+   JNODE_RIGHT_CONNECTED), if left or right sibling pointer contains actual
+   value (even NULL), corresponded JNODE_*_CONNECTED bit is set.
+
+   Reiser4 tree operations which may allocate new znodes (CBK, tree balancing)
+   take care about searching (hash table lookup may be required) of znode
+   neighbors, establishing sibling pointers between them and setting
+   JNODE_*_CONNECTED state bits. */
+
+/* adjusting of sibling pointers and `connected' states for two
+   neighbors; works if one neighbor is NULL (was not found). */
+
+/* FIXME-VS: this is unstatic-ed to use in tree.c in prepare_twig_cut */
+void link_left_and_right(znode * left, znode * right)
+{
+       assert("nikita-3275", check_sibling_list(left));
+       assert("nikita-3275", check_sibling_list(right));
+
+       if (left != NULL) {
+               if (left->right == NULL) {
+                       left->right = right;
+                       ZF_SET(left, JNODE_RIGHT_CONNECTED);
+
+                       ON_DEBUG(left->right_version =
+                                atomic_inc_return(&delim_key_version);
+                           );
+
+               } else if (ZF_ISSET(left->right, JNODE_HEARD_BANSHEE)
+                          && left->right != right) {
+
+                       ON_DEBUG(left->right->left_version =
+                                atomic_inc_return(&delim_key_version);
+                                left->right_version =
+                                atomic_inc_return(&delim_key_version););
+
+                       left->right->left = NULL;
+                       left->right = right;
+                       ZF_SET(left, JNODE_RIGHT_CONNECTED);
+               } else
+                       /*
+                        * there is a race condition in renew_sibling_link()
+                        * and assertions below check that it is only one
+                        * there. Thread T1 calls renew_sibling_link() without
+                        * GN_NO_ALLOC flag. zlook() doesn't find neighbor
+                        * node, but before T1 gets to the
+                        * link_left_and_right(), another thread T2 creates
+                        * neighbor node and connects it. check for
+                        * left->right == NULL above protects T1 from
+                        * overwriting correct left->right pointer installed
+                        * by T2.
+                        */
+                       assert("nikita-3302",
+                              right == NULL || left->right == right);
+       }
+       if (right != NULL) {
+               if (right->left == NULL) {
+                       right->left = left;
+                       ZF_SET(right, JNODE_LEFT_CONNECTED);
+
+                       ON_DEBUG(right->left_version =
+                                atomic_inc_return(&delim_key_version);
+                           );
+
+               } else if (ZF_ISSET(right->left, JNODE_HEARD_BANSHEE)
+                          && right->left != left) {
+
+                       ON_DEBUG(right->left->right_version =
+                                atomic_inc_return(&delim_key_version);
+                                right->left_version =
+                                atomic_inc_return(&delim_key_version););
+
+                       right->left->right = NULL;
+                       right->left = left;
+                       ZF_SET(right, JNODE_LEFT_CONNECTED);
+
+               } else
+                       assert("nikita-3303",
+                              left == NULL || right->left == left);
+       }
+       assert("nikita-3275", check_sibling_list(left));
+       assert("nikita-3275", check_sibling_list(right));
+}
+
+/* Audited by: umka (2002.06.14) */
+static void link_znodes(znode * first, znode * second, int to_left)
+{
+       if (to_left)
+               link_left_and_right(second, first);
+       else
+               link_left_and_right(first, second);
+}
+
+/* getting of next (to left or to right, depend on gn_to_left bit in flags)
+   coord's unit position in horizontal direction, even across node
+   boundary. Should be called under tree lock, it protects nonexistence of
+   sibling link on parent level, if lock_side_neighbor() fails with
+   -ENOENT. */
+static int far_next_coord(coord_t * coord, lock_handle * handle, int flags)
+{
+       int ret;
+       znode *node;
+       reiser4_tree *tree;
+
+       assert("umka-243", coord != NULL);
+       assert("umka-244", handle != NULL);
+       assert("zam-1069", handle->node == NULL);
+
+       ret =
+           (flags & GN_GO_LEFT) ? coord_prev_unit(coord) :
+           coord_next_unit(coord);
+       if (!ret)
+               return 0;
+
+       ret =
+           lock_side_neighbor(handle, coord->node, ZNODE_READ_LOCK, flags, 0);
+       if (ret)
+               return ret;
+
+       node = handle->node;
+       tree = znode_get_tree(node);
+       write_unlock_tree(tree);
+
+       coord_init_zero(coord);
+
+       /* We avoid synchronous read here if it is specified by flag. */
+       if ((flags & GN_ASYNC) && znode_page(handle->node) == NULL) {
+               ret = jstartio(ZJNODE(handle->node));
+               if (!ret)
+                       ret = -E_REPEAT;
+               goto error_locked;
+       }
+
+       /* corresponded zrelse() should be called by the clients of
+          far_next_coord(), in place when this node gets unlocked. */
+       ret = zload(handle->node);
+       if (ret)
+               goto error_locked;
+
+       if (flags & GN_GO_LEFT)
+               coord_init_last_unit(coord, node);
+       else
+               coord_init_first_unit(coord, node);
+
+       if (0) {
+             error_locked:
+               longterm_unlock_znode(handle);
+       }
+       write_lock_tree(tree);
+       return ret;
+}
+
+/* Very significant function which performs a step in horizontal direction
+   when sibling pointer is not available.  Actually, it is only function which
+   does it.
+   Note: this function does not restore locking status at exit,
+   caller should does care about proper unlocking and zrelsing */
+static int
+renew_sibling_link(coord_t * coord, lock_handle * handle, znode * child,
+                  tree_level level, int flags, int *nr_locked)
+{
+       int ret;
+       int to_left = flags & GN_GO_LEFT;
+       reiser4_block_nr da;
+       /* parent of the neighbor node; we set it to parent until not sharing
+          of one parent between child and neighbor node is detected */
+       znode *side_parent = coord->node;
+       reiser4_tree *tree = znode_get_tree(child);
+       znode *neighbor = NULL;
+
+       assert("umka-245", coord != NULL);
+       assert("umka-246", handle != NULL);
+       assert("umka-247", child != NULL);
+       assert("umka-303", tree != NULL);
+
+       init_lh(handle);
+       write_lock_tree(tree);
+       ret = far_next_coord(coord, handle, flags);
+
+       if (ret) {
+               if (ret != -ENOENT) {
+                       write_unlock_tree(tree);
+                       return ret;
+               }
+       } else {
+               item_plugin *iplug;
+
+               if (handle->node != NULL) {
+                       (*nr_locked)++;
+                       side_parent = handle->node;
+               }
+
+               /* does coord object points to internal item? We do not
+                  support sibling pointers between znode for formatted and
+                  unformatted nodes and return -E_NO_NEIGHBOR in that case. */
+               iplug = item_plugin_by_coord(coord);
+               if (!item_is_internal(coord)) {
+                       link_znodes(child, NULL, to_left);
+                       write_unlock_tree(tree);
+                       /* we know there can't be formatted neighbor */
+                       return RETERR(-E_NO_NEIGHBOR);
+               }
+               write_unlock_tree(tree);
+
+               iplug->s.internal.down_link(coord, NULL, &da);
+
+               if (flags & GN_NO_ALLOC) {
+                       neighbor = zlook(tree, &da);
+               } else {
+                       neighbor =
+                           zget(tree, &da, side_parent, level,
+                                reiser4_ctx_gfp_mask_get());
+               }
+
+               if (IS_ERR(neighbor)) {
+                       ret = PTR_ERR(neighbor);
+                       return ret;
+               }
+
+               if (neighbor)
+                       /* update delimiting keys */
+                       set_child_delimiting_keys(coord->node, coord, neighbor);
+
+               write_lock_tree(tree);
+       }
+
+       if (likely(neighbor == NULL ||
+                  (znode_get_level(child) == znode_get_level(neighbor)
+                   && child != neighbor)))
+               link_znodes(child, neighbor, to_left);
+       else {
+               warning("nikita-3532",
+                       "Sibling nodes on the different levels: %i != %i\n",
+                       znode_get_level(child), znode_get_level(neighbor));
+               ret = RETERR(-EIO);
+       }
+
+       write_unlock_tree(tree);
+
+       /* if GN_NO_ALLOC isn't set we keep reference to neighbor znode */
+       if (neighbor != NULL && (flags & GN_NO_ALLOC))
+               /* atomic_dec(&ZJNODE(neighbor)->x_count); */
+               zput(neighbor);
+
+       return ret;
+}
+
+/* This function is for establishing of one side relation. */
+/* Audited by: umka (2002.06.14) */
+static int connect_one_side(coord_t * coord, znode * node, int flags)
+{
+       coord_t local;
+       lock_handle handle;
+       int nr_locked;
+       int ret;
+
+       assert("umka-248", coord != NULL);
+       assert("umka-249", node != NULL);
+
+       coord_dup_nocheck(&local, coord);
+
+       init_lh(&handle);
+
+       ret =
+           renew_sibling_link(&local, &handle, node, znode_get_level(node),
+                              flags | GN_NO_ALLOC, &nr_locked);
+
+       if (handle.node != NULL) {
+               /* complementary operations for zload() and lock() in far_next_coord() */
+               zrelse(handle.node);
+               longterm_unlock_znode(&handle);
+       }
+
+       /* we catch error codes which are not interesting for us because we
+          run renew_sibling_link() only for znode connection. */
+       if (ret == -ENOENT || ret == -E_NO_NEIGHBOR)
+               return 0;
+
+       return ret;
+}
+
+/* if @child is not in `connected' state, performs hash searches for left and
+   right neighbor nodes and establishes horizontal sibling links */
+/* Audited by: umka (2002.06.14), umka (2002.06.15) */
+int connect_znode(coord_t * parent_coord, znode * child)
+{
+       reiser4_tree *tree = znode_get_tree(child);
+       int ret = 0;
+
+       assert("zam-330", parent_coord != NULL);
+       assert("zam-331", child != NULL);
+       assert("zam-332", parent_coord->node != NULL);
+       assert("umka-305", tree != NULL);
+
+       /* it is trivial to `connect' root znode because it can't have
+          neighbors */
+       if (znode_above_root(parent_coord->node)) {
+               child->left = NULL;
+               child->right = NULL;
+               ZF_SET(child, JNODE_LEFT_CONNECTED);
+               ZF_SET(child, JNODE_RIGHT_CONNECTED);
+
+               ON_DEBUG(child->left_version =
+                        atomic_inc_return(&delim_key_version);
+                        child->right_version =
+                        atomic_inc_return(&delim_key_version););
+
+               return 0;
+       }
+
+       /* load parent node */
+       coord_clear_iplug(parent_coord);
+       ret = zload(parent_coord->node);
+
+       if (ret != 0)
+               return ret;
+
+       /* protect `connected' state check by tree_lock */
+       read_lock_tree(tree);
+
+       if (!znode_is_right_connected(child)) {
+               read_unlock_tree(tree);
+               /* connect right (default is right) */
+               ret = connect_one_side(parent_coord, child, GN_NO_ALLOC);
+               if (ret)
+                       goto zrelse_and_ret;
+
+               read_lock_tree(tree);
+       }
+
+       ret = znode_is_left_connected(child);
+
+       read_unlock_tree(tree);
+
+       if (!ret) {
+               ret =
+                   connect_one_side(parent_coord, child,
+                                    GN_NO_ALLOC | GN_GO_LEFT);
+       } else
+               ret = 0;
+
+      zrelse_and_ret:
+       zrelse(parent_coord->node);
+
+       return ret;
+}
+
+/* this function is like renew_sibling_link() but allocates neighbor node if
+   it doesn't exist and `connects' it. It may require making two steps in
+   horizontal direction, first one for neighbor node finding/allocation,
+   second one is for finding neighbor of neighbor to connect freshly allocated
+   znode. */
+/* Audited by: umka (2002.06.14), umka (2002.06.15) */
+static int
+renew_neighbor(coord_t * coord, znode * node, tree_level level, int flags)
+{
+       coord_t local;
+       lock_handle empty[2];
+       reiser4_tree *tree = znode_get_tree(node);
+       znode *neighbor = NULL;
+       int nr_locked = 0;
+       int ret;
+
+       assert("umka-250", coord != NULL);
+       assert("umka-251", node != NULL);
+       assert("umka-307", tree != NULL);
+       assert("umka-308", level <= tree->height);
+
+       /* umka (2002.06.14)
+          Here probably should be a check for given "level" validness.
+          Something like assert("xxx-yyy", level < REAL_MAX_ZTREE_HEIGHT);
+        */
+
+       coord_dup(&local, coord);
+
+       ret =
+           renew_sibling_link(&local, &empty[0], node, level,
+                              flags & ~GN_NO_ALLOC, &nr_locked);
+       if (ret)
+               goto out;
+
+       /* tree lock is not needed here because we keep parent node(s) locked
+          and reference to neighbor znode incremented */
+       neighbor = (flags & GN_GO_LEFT) ? node->left : node->right;
+
+       read_lock_tree(tree);
+       ret = znode_is_connected(neighbor);
+       read_unlock_tree(tree);
+       if (ret) {
+               ret = 0;
+               goto out;
+       }
+
+       ret =
+           renew_sibling_link(&local, &empty[nr_locked], neighbor, level,
+                              flags | GN_NO_ALLOC, &nr_locked);
+       /* second renew_sibling_link() call is used for znode connection only,
+          so we can live with these errors */
+       if (-ENOENT == ret || -E_NO_NEIGHBOR == ret)
+               ret = 0;
+
+      out:
+
+       for (--nr_locked; nr_locked >= 0; --nr_locked) {
+               zrelse(empty[nr_locked].node);
+               longterm_unlock_znode(&empty[nr_locked]);
+       }
+
+       if (neighbor != NULL)
+               /* decrement znode reference counter without actually
+                  releasing it. */
+               atomic_dec(&ZJNODE(neighbor)->x_count);
+
+       return ret;
+}
+
+/*
+   reiser4_get_neighbor() -- lock node's neighbor.
+
+   reiser4_get_neighbor() locks node's neighbor (left or right one, depends on
+   given parameter) using sibling link to it. If sibling link is not available
+   (i.e. neighbor znode is not in cache) and flags allow read blocks, we go one
+   level up for information about neighbor's disk address. We lock node's
+   parent, if it is common parent for both 'node' and its neighbor, neighbor's
+   disk address is in next (to left or to right) down link from link that points
+   to original node. If not, we need to lock parent's neighbor, read its content
+   and take first(last) downlink with neighbor's disk address.  That locking
+   could be done by using sibling link and lock_neighbor() function, if sibling
+   link exists. In another case we have to go level up again until we find
+   common parent or valid sibling link. Then go down
+   allocating/connecting/locking/reading nodes until neighbor of first one is
+   locked.
+
+   @neighbor:  result lock handle,
+   @node: a node which we lock neighbor of,
+   @lock_mode: lock mode {LM_READ, LM_WRITE},
+   @flags: logical OR of {GN_*} (see description above) subset.
+
+   @return: 0 if success, negative value if lock was impossible due to an error
+   or lack of neighbor node.
+*/
+
+/* Audited by: umka (2002.06.14), umka (2002.06.15) */
+int
+reiser4_get_neighbor(lock_handle * neighbor, znode * node,
+                    znode_lock_mode lock_mode, int flags)
+{
+       reiser4_tree *tree = znode_get_tree(node);
+       lock_handle path[REAL_MAX_ZTREE_HEIGHT];
+
+       coord_t coord;
+
+       tree_level base_level;
+       tree_level h = 0;
+       int ret;
+
+       assert("umka-252", tree != NULL);
+       assert("umka-253", neighbor != NULL);
+       assert("umka-254", node != NULL);
+
+       base_level = znode_get_level(node);
+
+       assert("umka-310", base_level <= tree->height);
+
+       coord_init_zero(&coord);
+
+      again:
+       /* first, we try to use simple lock_neighbor() which requires sibling
+          link existence */
+       read_lock_tree(tree);
+       ret = lock_side_neighbor(neighbor, node, lock_mode, flags, 1);
+       read_unlock_tree(tree);
+       if (!ret) {
+               /* load znode content if it was specified */
+               if (flags & GN_LOAD_NEIGHBOR) {
+                       ret = zload(node);
+                       if (ret)
+                               longterm_unlock_znode(neighbor);
+               }
+               return ret;
+       }
+
+       /* only -ENOENT means we may look upward and try to connect
+          @node with its neighbor (if @flags allow us to do it) */
+       if (ret != -ENOENT || !(flags & GN_CAN_USE_UPPER_LEVELS))
+               return ret;
+
+       /* before establishing of sibling link we lock parent node; it is
+          required by renew_neighbor() to work.  */
+       init_lh(&path[0]);
+       ret = reiser4_get_parent(&path[0], node, ZNODE_READ_LOCK);
+       if (ret)
+               return ret;
+       if (znode_above_root(path[0].node)) {
+               longterm_unlock_znode(&path[0]);
+               return RETERR(-E_NO_NEIGHBOR);
+       }
+
+       while (1) {
+               znode *child = (h == 0) ? node : path[h - 1].node;
+               znode *parent = path[h].node;
+
+               ret = zload(parent);
+               if (ret)
+                       break;
+
+               ret = find_child_ptr(parent, child, &coord);
+
+               if (ret) {
+                       zrelse(parent);
+                       break;
+               }
+
+               /* try to establish missing sibling link */
+               ret = renew_neighbor(&coord, child, h + base_level, flags);
+
+               zrelse(parent);
+
+               switch (ret) {
+               case 0:
+                       /* unlocking of parent znode prevents simple
+                          deadlock situation */
+                       done_lh(&path[h]);
+
+                       /* depend on tree level we stay on we repeat first
+                          locking attempt ...  */
+                       if (h == 0)
+                               goto again;
+
+                       /* ... or repeat establishing of sibling link at
+                          one level below. */
+                       --h;
+                       break;
+
+               case -ENOENT:
+                       /* sibling link is not available -- we go
+                          upward. */
+                       init_lh(&path[h + 1]);
+                       ret =
+                           reiser4_get_parent(&path[h + 1], parent,
+                                              ZNODE_READ_LOCK);
+                       if (ret)
+                               goto fail;
+                       ++h;
+                       if (znode_above_root(path[h].node)) {
+                               ret = RETERR(-E_NO_NEIGHBOR);
+                               goto fail;
+                       }
+                       break;
+
+               case -E_DEADLOCK:
+                       /* there was lock request from hi-pri locker. if
+                          it is possible we unlock last parent node and
+                          re-lock it again. */
+                       for (; reiser4_check_deadlock(); h--) {
+                               done_lh(&path[h]);
+                               if (h == 0)
+                                       goto fail;
+                       }
+
+                       break;
+
+               default:        /* other errors. */
+                       goto fail;
+               }
+       }
+      fail:
+       ON_DEBUG(check_lock_node_data(node));
+       ON_DEBUG(check_lock_data());
+
+       /* unlock path */
+       do {
+               /* FIXME-Zam: when we get here from case -E_DEADLOCK's goto
+                  fail; path[0] is already done_lh-ed, therefore
+                  longterm_unlock_znode(&path[h]); is not applicable */
+               done_lh(&path[h]);
+               --h;
+       } while (h + 1 != 0);
+
+       return ret;
+}
+
+/* remove node from sibling list */
+/* Audited by: umka (2002.06.14) */
+void sibling_list_remove(znode * node)
+{
+       reiser4_tree *tree;
+
+       tree = znode_get_tree(node);
+       assert("umka-255", node != NULL);
+       assert_rw_write_locked(&(tree->tree_lock));
+       assert("nikita-3275", check_sibling_list(node));
+
+       write_lock_dk(tree);
+       if (znode_is_right_connected(node) && node->right != NULL &&
+           znode_is_left_connected(node) && node->left != NULL) {
+               assert("zam-32245",
+                      keyeq(znode_get_rd_key(node),
+                            znode_get_ld_key(node->right)));
+               znode_set_rd_key(node->left, znode_get_ld_key(node->right));
+       }
+       write_unlock_dk(tree);
+
+       if (znode_is_right_connected(node) && node->right != NULL) {
+               assert("zam-322", znode_is_left_connected(node->right));
+               node->right->left = node->left;
+               ON_DEBUG(node->right->left_version =
+                        atomic_inc_return(&delim_key_version);
+                   );
+       }
+       if (znode_is_left_connected(node) && node->left != NULL) {
+               assert("zam-323", znode_is_right_connected(node->left));
+               node->left->right = node->right;
+               ON_DEBUG(node->left->right_version =
+                        atomic_inc_return(&delim_key_version);
+                   );
+       }
+
+       ZF_CLR(node, JNODE_LEFT_CONNECTED);
+       ZF_CLR(node, JNODE_RIGHT_CONNECTED);
+       ON_DEBUG(node->left = node->right = NULL;
+                node->left_version = atomic_inc_return(&delim_key_version);
+                node->right_version = atomic_inc_return(&delim_key_version););
+       assert("nikita-3276", check_sibling_list(node));
+}
+
+/* disconnect node from sibling list */
+void sibling_list_drop(znode * node)
+{
+       znode *right;
+       znode *left;
+
+       assert("nikita-2464", node != NULL);
+       assert("nikita-3277", check_sibling_list(node));
+
+       right = node->right;
+       if (right != NULL) {
+               assert("nikita-2465", znode_is_left_connected(right));
+               right->left = NULL;
+               ON_DEBUG(right->left_version =
+                        atomic_inc_return(&delim_key_version);
+                   );
+       }
+       left = node->left;
+       if (left != NULL) {
+               assert("zam-323", znode_is_right_connected(left));
+               left->right = NULL;
+               ON_DEBUG(left->right_version =
+                        atomic_inc_return(&delim_key_version);
+                   );
+       }
+       ZF_CLR(node, JNODE_LEFT_CONNECTED);
+       ZF_CLR(node, JNODE_RIGHT_CONNECTED);
+       ON_DEBUG(node->left = node->right = NULL;
+                node->left_version = atomic_inc_return(&delim_key_version);
+                node->right_version = atomic_inc_return(&delim_key_version););
+}
+
+/* Insert new node into sibling list. Regular balancing inserts new node
+   after (at right side) existing and locked node (@before), except one case
+   of adding new tree root node. @before should be NULL in that case. */
+void sibling_list_insert_nolock(znode * new, znode * before)
+{
+       assert("zam-334", new != NULL);
+       assert("nikita-3298", !znode_is_left_connected(new));
+       assert("nikita-3299", !znode_is_right_connected(new));
+       assert("nikita-3300", new->left == NULL);
+       assert("nikita-3301", new->right == NULL);
+       assert("nikita-3278", check_sibling_list(new));
+       assert("nikita-3279", check_sibling_list(before));
+
+       if (before != NULL) {
+               assert("zam-333", znode_is_connected(before));
+               new->right = before->right;
+               new->left = before;
+               ON_DEBUG(new->right_version =
+                        atomic_inc_return(&delim_key_version);
+                        new->left_version =
+                        atomic_inc_return(&delim_key_version););
+               if (before->right != NULL) {
+                       before->right->left = new;
+                       ON_DEBUG(before->right->left_version =
+                                atomic_inc_return(&delim_key_version);
+                           );
+               }
+               before->right = new;
+               ON_DEBUG(before->right_version =
+                        atomic_inc_return(&delim_key_version);
+                   );
+       } else {
+               new->right = NULL;
+               new->left = NULL;
+               ON_DEBUG(new->right_version =
+                        atomic_inc_return(&delim_key_version);
+                        new->left_version =
+                        atomic_inc_return(&delim_key_version););
+       }
+       ZF_SET(new, JNODE_LEFT_CONNECTED);
+       ZF_SET(new, JNODE_RIGHT_CONNECTED);
+       assert("nikita-3280", check_sibling_list(new));
+       assert("nikita-3281", check_sibling_list(before));
+}
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/tree_walk.h linux-2.6.20/fs/reiser4/tree_walk.h
--- linux-2.6.20.orig/fs/reiser4/tree_walk.h    1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/tree_walk.h 2007-05-06 14:50:43.887034467 +0400
@@ -0,0 +1,125 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+/* definitions of reiser4 tree walk functions */
+
+#ifndef __FS_REISER4_TREE_WALK_H__
+#define __FS_REISER4_TREE_WALK_H__
+
+#include "debug.h"
+#include "forward.h"
+
+/* establishes horizontal links between cached znodes */
+int connect_znode(coord_t * coord, znode * node);
+
+/* tree traversal functions (reiser4_get_parent(), reiser4_get_neighbor())
+  have the following common arguments:
+
+  return codes:
+
+  @return : 0        - OK,
+
+ZAM-FIXME-HANS: wrong return code name.  Change them all.
+           -ENOENT  - neighbor is not in cache, what is detected by sibling
+                      link absence.
+
+            -E_NO_NEIGHBOR - we are sure that neighbor (or parent) node cannot be
+                       found (because we are left-/right- most node of the
+                      tree, for example). Also, this return code is for
+                      reiser4_get_parent() when we see no parent link -- it
+                      means that our node is root node.
+
+            -E_DEADLOCK - deadlock detected (request from high-priority process
+                      received), other error codes are conformed to
+                      /usr/include/asm/errno.h .
+*/
+
+int
+reiser4_get_parent_flags(lock_handle * result, znode * node,
+                        znode_lock_mode mode, int flags);
+
+/* bits definition for reiser4_get_neighbor function `flags' arg. */
+typedef enum {
+       /* If sibling pointer is NULL, this flag allows get_neighbor() to try to
+        * find not allocated not connected neigbor by going though upper
+        * levels */
+       GN_CAN_USE_UPPER_LEVELS = 0x1,
+       /* locking left neighbor instead of right one */
+       GN_GO_LEFT = 0x2,
+       /* automatically load neighbor node content */
+       GN_LOAD_NEIGHBOR = 0x4,
+       /* return -E_REPEAT if can't lock  */
+       GN_TRY_LOCK = 0x8,
+       /* used internally in tree_walk.c, causes renew_sibling to not
+          allocate neighbor znode, but only search for it in znode cache */
+       GN_NO_ALLOC = 0x10,
+       /* do not go across atom boundaries */
+       GN_SAME_ATOM = 0x20,
+       /* allow to lock not connected nodes */
+       GN_ALLOW_NOT_CONNECTED = 0x40,
+       /*  Avoid synchronous jload, instead, call jstartio() and return -E_REPEAT. */
+       GN_ASYNC = 0x80
+} znode_get_neigbor_flags;
+
+/* A commonly used wrapper for reiser4_get_parent_flags(). */
+static inline int reiser4_get_parent(lock_handle * result, znode * node,
+                                    znode_lock_mode mode)
+{
+       return reiser4_get_parent_flags(result, node, mode,
+                                       GN_ALLOW_NOT_CONNECTED);
+}
+
+int reiser4_get_neighbor(lock_handle * neighbor, znode * node,
+                        znode_lock_mode lock_mode, int flags);
+
+/* there are wrappers for most common usages of reiser4_get_neighbor() */
+static inline int
+reiser4_get_left_neighbor(lock_handle * result, znode * node, int lock_mode,
+                         int flags)
+{
+       return reiser4_get_neighbor(result, node, lock_mode,
+                                   flags | GN_GO_LEFT);
+}
+
+static inline int
+reiser4_get_right_neighbor(lock_handle * result, znode * node, int lock_mode,
+                          int flags)
+{
+       ON_DEBUG(check_lock_node_data(node));
+       ON_DEBUG(check_lock_data());
+       return reiser4_get_neighbor(result, node, lock_mode,
+                                   flags & (~GN_GO_LEFT));
+}
+
+extern void sibling_list_remove(znode * node);
+extern void sibling_list_drop(znode * node);
+extern void sibling_list_insert_nolock(znode * new, znode * before);
+extern void link_left_and_right(znode * left, znode * right);
+
+/* Functions called by tree_walk() when tree_walk() ...  */
+struct tree_walk_actor {
+       /* ... meets a formatted node, */
+       int (*process_znode) (tap_t *, void *);
+       /* ... meets an extent, */
+       int (*process_extent) (tap_t *, void *);
+       /* ... begins tree traversal or repeats it after -E_REPEAT was returned by
+        * node or extent processing functions. */
+       int (*before) (void *);
+};
+
+#if REISER4_DEBUG
+int check_sibling_list(znode * node);
+#else
+#define check_sibling_list(n) (1)
+#endif
+
+#endif                         /* __FS_REISER4_TREE_WALK_H__ */
+
+/*
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/txnmgr.c linux-2.6.20/fs/reiser4/txnmgr.c
--- linux-2.6.20.orig/fs/reiser4/txnmgr.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/txnmgr.c    2007-05-06 14:50:43.895036966 +0400
@@ -0,0 +1,3164 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Joshua MacDonald wrote the first draft of this code. */
+
+/* ZAM-LONGTERM-FIXME-HANS: The locking in this file is badly designed, and a
+filesystem scales only as well as its worst locking design.  You need to
+substantially restructure this code. Josh was not as experienced a programmer
+as you.  Particularly review how the locking style differs from what you did
+for znodes usingt hi-lo priority locking, and present to me an opinion on
+whether the differences are well founded.  */
+
+/* I cannot help but to disagree with the sentiment above. Locking of
+ * transaction manager is _not_ badly designed, and, at the very least, is not
+ * the scaling bottleneck. Scaling bottleneck is _exactly_ hi-lo priority
+ * locking on znodes, especially on the root node of the tree. --nikita,
+ * 2003.10.13 */
+
+/* The txnmgr is a set of interfaces that keep track of atoms and transcrash handles.  The
+   txnmgr processes capture_block requests and manages the relationship between jnodes and
+   atoms through the various stages of a transcrash, and it also oversees the fusion and
+   capture-on-copy processes.  The main difficulty with this task is maintaining a
+   deadlock-free lock ordering between atoms and jnodes/handles.  The reason for the
+   difficulty is that jnodes, handles, and atoms contain pointer circles, and the cycle
+   must be broken.  The main requirement is that atom-fusion be deadlock free, so once you
+   hold the atom_lock you may then wait to acquire any jnode or handle lock.  This implies
+   that any time you check the atom-pointer of a jnode or handle and then try to lock that
+   atom, you must use trylock() and possibly reverse the order.
+
+   This code implements the design documented at:
+
+     http://namesys.com/txn-doc.html
+
+ZAM-FIXME-HANS: update v4.html to contain all of the information present in the above (but updated), and then remove the
+above document and reference the new.  Be sure to provide some credit to Josh.  I already have some writings on this
+topic in v4.html, but they are lacking in details present in the above.  Cure that.  Remember to write for the bright 12
+year old --- define all technical terms used.
+
+*/
+
+/* Thoughts on the external transaction interface:
+
+   In the current code, a TRANSCRASH handle is created implicitly by reiser4_init_context() (which
+   creates state that lasts for the duration of a system call and is called at the start
+   of ReiserFS methods implementing VFS operations), and closed by reiser4_exit_context(),
+   occupying the scope of a single system call.  We wish to give certain applications an
+   interface to begin and close (commit) transactions.  Since our implementation of
+   transactions does not yet support isolation, allowing an application to open a
+   transaction implies trusting it to later close the transaction.  Part of the
+   transaction interface will be aimed at enabling that trust, but the interface for
+   actually using transactions is fairly narrow.
+
+   BEGIN_TRANSCRASH: Returns a transcrash identifier.  It should be possible to translate
+   this identifier into a string that a shell-script could use, allowing you to start a
+   transaction by issuing a command.  Once open, the transcrash should be set in the task
+   structure, and there should be options (I suppose) to allow it to be carried across
+   fork/exec.  A transcrash has several options:
+
+     - READ_FUSING or WRITE_FUSING: The default policy is for txn-capture to capture only
+     on writes (WRITE_FUSING) and allow "dirty reads".  If the application wishes to
+     capture on reads as well, it should set READ_FUSING.
+
+     - TIMEOUT: Since a non-isolated transcrash cannot be undone, every transcrash must
+     eventually close (or else the machine must crash).  If the application dies an
+     unexpected death with an open transcrash, for example, or if it hangs for a long
+     duration, one solution (to avoid crashing the machine) is to simply close it anyway.
+     This is a dangerous option, but it is one way to solve the problem until isolated
+     transcrashes are available for untrusted applications.
+
+     It seems to be what databases do, though it is unclear how one avoids a DoS attack
+     creating a vulnerability based on resource starvation.  Guaranteeing that some
+     minimum amount of computational resources are made available would seem more correct
+     than guaranteeing some amount of time.  When we again have someone to code the work,
+     this issue should be considered carefully.  -Hans
+
+   RESERVE_BLOCKS: A running transcrash should indicate to the transaction manager how
+   many dirty blocks it expects.  The reserve_blocks interface should be called at a point
+   where it is safe for the application to fail, because the system may not be able to
+   grant the allocation and the application must be able to back-out.  For this reason,
+   the number of reserve-blocks can also be passed as an argument to BEGIN_TRANSCRASH, but
+   the application may also wish to extend the allocation after beginning its transcrash.
+
+   CLOSE_TRANSCRASH: The application closes the transcrash when it is finished making
+   modifications that require transaction protection.  When isolated transactions are
+   supported the CLOSE operation is replaced by either COMMIT or ABORT.  For example, if a
+   RESERVE_BLOCKS call fails for the application, it should "abort" by calling
+   CLOSE_TRANSCRASH, even though it really commits any changes that were made (which is
+   why, for safety, the application should call RESERVE_BLOCKS before making any changes).
+
+   For actually implementing these out-of-system-call-scopped transcrashes, the
+   reiser4_context has a "txn_handle *trans" pointer that may be set to an open
+   transcrash.  Currently there are no dynamically-allocated transcrashes, but there is a
+   "struct kmem_cache *_txnh_slab" created for that purpose in this file.
+*/
+
+/* Extending the other system call interfaces for future transaction features:
+
+   Specialized applications may benefit from passing flags to the ordinary system call
+   interface such as read(), write(), or stat().  For example, the application specifies
+   WRITE_FUSING by default but wishes to add that a certain read() command should be
+   treated as READ_FUSING.  But which read?  Is it the directory-entry read, the stat-data
+   read, or the file-data read?  These issues are straight-forward, but there are a lot of
+   them and adding the necessary flags-passing code will be tedious.
+
+   When supporting isolated transactions, there is a corresponding READ_MODIFY_WRITE (RMW)
+   flag, which specifies that although it is a read operation being requested, a
+   write-lock should be taken.  The reason is that read-locks are shared while write-locks
+   are exclusive, so taking a read-lock when a later-write is known in advance will often
+   leads to deadlock.  If a reader knows it will write later, it should issue read
+   requests with the RMW flag set.
+*/
+
+/*
+   The znode/atom deadlock avoidance.
+
+   FIXME(Zam): writing of this comment is in progress.
+
+   The atom's special stage ASTAGE_CAPTURE_WAIT introduces a kind of atom's
+   long-term locking, which makes reiser4 locking scheme more complex.  It had
+   deadlocks until we implement deadlock avoidance algorithms.  That deadlocks
+   looked as the following: one stopped thread waits for a long-term lock on
+   znode, the thread who owns that lock waits when fusion with another atom will
+   be allowed.
+
+   The source of the deadlocks is an optimization of not capturing index nodes
+   for read.  Let's prove it.  Suppose we have dumb node capturing scheme which
+   unconditionally captures each block before locking it.
+
+   That scheme has no deadlocks.  Let's begin with the thread which stage is
+   ASTAGE_CAPTURE_WAIT and it waits for a znode lock.  The thread can't wait for
+   a capture because it's stage allows fusion with any atom except which are
+   being committed currently. A process of atom commit can't deadlock because
+   atom commit procedure does not acquire locks and does not fuse with other
+   atoms.  Reiser4 does capturing right before going to sleep inside the
+   longtertm_lock_znode() function, it means the znode which we want to lock is
+   already captured and its atom is in ASTAGE_CAPTURE_WAIT stage.  If we
+   continue the analysis we understand that no one process in the sequence may
+   waits atom fusion.  Thereby there are no deadlocks of described kind.
+
+   The capturing optimization makes the deadlocks possible.  A thread can wait a
+   lock which owner did not captured that node.  The lock owner's current atom
+   is not fused with the first atom and it does not get a ASTAGE_CAPTURE_WAIT
+   state. A deadlock is possible when that atom meets another one which is in
+   ASTAGE_CAPTURE_WAIT already.
+
+   The deadlock avoidance scheme includes two algorithms:
+
+   First algorithm is used when a thread captures a node which is locked but not
+   captured by another thread.  Those nodes are marked MISSED_IN_CAPTURE at the
+   moment we skip their capturing.  If such a node (marked MISSED_IN_CAPTURE) is
+   being captured by a thread with current atom is in ASTAGE_CAPTURE_WAIT, the
+   routine which forces all lock owners to join with current atom is executed.
+
+   Second algorithm does not allow to skip capturing of already captured nodes.
+
+   Both algorithms together prevent waiting a longterm lock without atom fusion
+   with atoms of all lock owners, which is a key thing for getting atom/znode
+   locking deadlocks.
+*/
+
+/*
+ * Transactions and mmap(2).
+ *
+ *     1. Transactions are not supported for accesses through mmap(2), because
+ *     this would effectively amount to user-level transactions whose duration
+ *     is beyond control of the kernel.
+ *
+ *     2. That said, we still want to preserve some decency with regard to
+ *     mmap(2). During normal write(2) call, following sequence of events
+ *     happens:
+ *
+ *         1. page is created;
+ *
+ *         2. jnode is created, dirtied and captured into current atom.
+ *
+ *         3. extent is inserted and modified.
+ *
+ *     Steps (2) and (3) take place under long term lock on the twig node.
+ *
+ *     When file is accessed through mmap(2) page is always created during
+ *     page fault.
+ *     After this (in reiser4_readpage()->reiser4_readpage_extent()):
+ *
+ *         1. if access is made to non-hole page new jnode is created, (if
+ *         necessary)
+ *
+ *         2. if access is made to the hole page, jnode is not created (XXX
+ *         not clear why).
+ *
+ *     Also, even if page is created by write page fault it is not marked
+ *     dirty immediately by handle_mm_fault(). Probably this is to avoid races
+ *     with page write-out.
+ *
+ *     Dirty bit installed by hardware is only transferred to the struct page
+ *     later, when page is unmapped (in zap_pte_range(), or
+ *     try_to_unmap_one()).
+ *
+ *     So, with mmap(2) we have to handle following irksome situations:
+ *
+ *         1. there exists modified page (clean or dirty) without jnode
+ *
+ *         2. there exists modified page (clean or dirty) with clean jnode
+ *
+ *         3. clean page which is a part of atom can be transparently modified
+ *         at any moment through mapping without becoming dirty.
+ *
+ *     (1) and (2) can lead to the out-of-memory situation: ->writepage()
+ *     doesn't know what to do with such pages and ->sync_sb()/->writepages()
+ *     don't see them, because these methods operate on atoms.
+ *
+ *     (3) can lead to the loss of data: suppose we have dirty page with dirty
+ *     captured jnode captured by some atom. As part of early flush (for
+ *     example) page was written out. Dirty bit was cleared on both page and
+ *     jnode. After this page is modified through mapping, but kernel doesn't
+ *     notice and just discards page and jnode as part of commit. (XXX
+ *     actually it doesn't, because to reclaim page ->releasepage() has to be
+ *     called and before this dirty bit will be transferred to the struct
+ *     page).
+ *
+ */
+
+#include "debug.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "wander.h"
+#include "ktxnmgrd.h"
+#include "super.h"
+#include "page_cache.h"
+#include "reiser4.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "flush.h"
+
+#include <asm/atomic.h>
+#include <linux/types.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h>
+#include <linux/swap.h>                /* for totalram_pages */
+
+static void atom_free(txn_atom * atom);
+
+static int commit_txnh(txn_handle * txnh);
+
+static void wakeup_atom_waitfor_list(txn_atom * atom);
+static void wakeup_atom_waiting_list(txn_atom * atom);
+
+static void capture_assign_txnh_nolock(txn_atom * atom, txn_handle * txnh);
+
+static void capture_assign_block_nolock(txn_atom * atom, jnode * node);
+
+static void fuse_not_fused_lock_owners(txn_handle * txnh, znode * node);
+
+static int capture_init_fusion(jnode * node, txn_handle * txnh,
+                              txn_capture mode);
+
+static int capture_fuse_wait(txn_handle *, txn_atom *, txn_atom *, txn_capture);
+
+static void capture_fuse_into(txn_atom * small, txn_atom * large);
+
+void reiser4_invalidate_list(struct list_head *);
+
+/* GENERIC STRUCTURES */
+
+typedef struct _txn_wait_links txn_wait_links;
+
+struct _txn_wait_links {
+       lock_stack *_lock_stack;
+       struct list_head _fwaitfor_link;
+       struct list_head _fwaiting_link;
+       int (*waitfor_cb) (txn_atom * atom, struct _txn_wait_links * wlinks);
+       int (*waiting_cb) (txn_atom * atom, struct _txn_wait_links * wlinks);
+};
+
+/* FIXME: In theory, we should be using the slab cache init & destructor
+   methods instead of, e.g., jnode_init, etc. */
+static struct kmem_cache *_atom_slab = NULL;
+/* this is for user-visible, cross system-call transactions. */
+static struct kmem_cache *_txnh_slab = NULL;
+
+/**
+ * init_txnmgr_static - create transaction manager slab caches
+ *
+ * Initializes caches of txn-atoms and txn_handle. It is part of reiser4 module
+ * initialization.
+ */
+int init_txnmgr_static(void)
+{
+       assert("jmacd-600", _atom_slab == NULL);
+       assert("jmacd-601", _txnh_slab == NULL);
+
+       ON_DEBUG(atomic_set(&flush_cnt, 0));
+
+       _atom_slab = kmem_cache_create("txn_atom", sizeof(txn_atom), 0,
+                                      SLAB_HWCACHE_ALIGN |
+                                      SLAB_RECLAIM_ACCOUNT, NULL, NULL);
+       if (_atom_slab == NULL)
+               return RETERR(-ENOMEM);
+
+       _txnh_slab = kmem_cache_create("txn_handle", sizeof(txn_handle), 0,
+                             SLAB_HWCACHE_ALIGN, NULL, NULL);
+       if (_txnh_slab == NULL) {
+               kmem_cache_destroy(_atom_slab);
+               _atom_slab = NULL;
+               return RETERR(-ENOMEM);
+       }
+
+       return 0;
+}
+
+/**
+ * done_txnmgr_static - delete txn_atom and txn_handle caches
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void done_txnmgr_static(void)
+{
+       destroy_reiser4_cache(&_atom_slab);
+       destroy_reiser4_cache(&_txnh_slab);
+}
+
+/**
+ * init_txnmgr - initialize a new transaction manager
+ * @mgr: pointer to transaction manager embedded in reiser4 super block
+ *
+ * This is called on mount. Makes necessary initializations.
+ */
+void reiser4_init_txnmgr(txn_mgr *mgr)
+{
+       assert("umka-169", mgr != NULL);
+
+       mgr->atom_count = 0;
+       mgr->id_count = 1;
+       INIT_LIST_HEAD(&mgr->atoms_list);
+       spin_lock_init(&mgr->tmgr_lock);
+       mutex_init(&mgr->commit_mutex);
+}
+
+/**
+ * reiser4_done_txnmgr - stop transaction manager
+ * @mgr: pointer to transaction manager embedded in reiser4 super block
+ *
+ * This is called on umount. Does sanity checks.
+ */
+void reiser4_done_txnmgr(txn_mgr *mgr)
+{
+       assert("umka-170", mgr != NULL);
+       assert("umka-1701", list_empty_careful(&mgr->atoms_list));
+       assert("umka-1702", mgr->atom_count == 0);
+}
+
+/* Initialize a transaction handle. */
+/* Audited by: umka (2002.06.13) */
+static void txnh_init(txn_handle * txnh, txn_mode mode)
+{
+       assert("umka-171", txnh != NULL);
+
+       txnh->mode = mode;
+       txnh->atom = NULL;
+       reiser4_ctx_gfp_mask_set();
+       txnh->flags = 0;
+       spin_lock_init(&txnh->hlock);
+       INIT_LIST_HEAD(&txnh->txnh_link);
+}
+
+#if REISER4_DEBUG
+/* Check if a transaction handle is clean. */
+static int txnh_isclean(txn_handle * txnh)
+{
+       assert("umka-172", txnh != NULL);
+       return txnh->atom == NULL &&
+               LOCK_CNT_NIL(spin_locked_txnh);
+}
+#endif
+
+/* Initialize an atom. */
+static void atom_init(txn_atom * atom)
+{
+       int level;
+
+       assert("umka-173", atom != NULL);
+
+       memset(atom, 0, sizeof(txn_atom));
+
+       atom->stage = ASTAGE_FREE;
+       atom->start_time = jiffies;
+
+       for (level = 0; level < REAL_MAX_ZTREE_HEIGHT + 1; level += 1)
+               INIT_LIST_HEAD(ATOM_DIRTY_LIST(atom, level));
+
+       INIT_LIST_HEAD(ATOM_CLEAN_LIST(atom));
+       INIT_LIST_HEAD(ATOM_OVRWR_LIST(atom));
+       INIT_LIST_HEAD(ATOM_WB_LIST(atom));
+       INIT_LIST_HEAD(&atom->inodes);
+       spin_lock_init(&(atom->alock));
+       /* list of transaction handles */
+       INIT_LIST_HEAD(&atom->txnh_list);
+       /* link to transaction manager's list of atoms */
+       INIT_LIST_HEAD(&atom->atom_link);
+       INIT_LIST_HEAD(&atom->fwaitfor_list);
+       INIT_LIST_HEAD(&atom->fwaiting_list);
+       blocknr_set_init(&atom->delete_set);
+       blocknr_set_init(&atom->wandered_map);
+
+       init_atom_fq_parts(atom);
+}
+
+#if REISER4_DEBUG
+/* Check if an atom is clean. */
+static int atom_isclean(txn_atom * atom)
+{
+       int level;
+
+       assert("umka-174", atom != NULL);
+
+       for (level = 0; level < REAL_MAX_ZTREE_HEIGHT + 1; level += 1) {
+               if (!list_empty_careful(ATOM_DIRTY_LIST(atom, level))) {
+                       return 0;
+               }
+       }
+
+       return  atom->stage == ASTAGE_FREE &&
+               atom->txnh_count == 0 &&
+               atom->capture_count == 0 &&
+               atomic_read(&atom->refcount) == 0 &&
+               (&atom->atom_link == atom->atom_link.next &&
+                &atom->atom_link == atom->atom_link.prev) &&
+               list_empty_careful(&atom->txnh_list) &&
+               list_empty_careful(ATOM_CLEAN_LIST(atom)) &&
+               list_empty_careful(ATOM_OVRWR_LIST(atom)) &&
+               list_empty_careful(ATOM_WB_LIST(atom)) &&
+               list_empty_careful(&atom->fwaitfor_list) &&
+               list_empty_careful(&atom->fwaiting_list) &&
+               atom_fq_parts_are_clean(atom);
+}
+#endif
+
+/* Begin a transaction in this context.  Currently this uses the reiser4_context's
+   trans_in_ctx, which means that transaction handles are stack-allocated.  Eventually
+   this will be extended to allow transaction handles to span several contexts. */
+/* Audited by: umka (2002.06.13) */
+void reiser4_txn_begin(reiser4_context * context)
+{
+       assert("jmacd-544", context->trans == NULL);
+
+       context->trans = &context->trans_in_ctx;
+
+       /* FIXME_LATER_JMACD Currently there's no way to begin a TXN_READ_FUSING
+          transcrash.  Default should be TXN_WRITE_FUSING.  Also, the _trans variable is
+          stack allocated right now, but we would like to allow for dynamically allocated
+          transcrashes that span multiple system calls.
+        */
+       txnh_init(context->trans, TXN_WRITE_FUSING);
+}
+
+/* Finish a transaction handle context. */
+int reiser4_txn_end(reiser4_context * context)
+{
+       long ret = 0;
+       txn_handle *txnh;
+
+       assert("umka-283", context != NULL);
+       assert("nikita-3012", reiser4_schedulable());
+       assert("vs-24", context == get_current_context());
+       assert("nikita-2967", lock_stack_isclean(get_current_lock_stack()));
+
+       txnh = context->trans;
+       if (txnh != NULL) {
+               if (txnh->atom != NULL)
+                       ret = commit_txnh(txnh);
+               assert("jmacd-633", txnh_isclean(txnh));
+               context->trans = NULL;
+       }
+       return ret;
+}
+
+void reiser4_txn_restart(reiser4_context * context)
+{
+       reiser4_txn_end(context);
+       reiser4_preempt_point();
+       reiser4_txn_begin(context);
+}
+
+void reiser4_txn_restart_current(void)
+{
+       reiser4_txn_restart(get_current_context());
+}
+
+/* TXN_ATOM */
+
+/* Get the atom belonging to a txnh, which is not locked.  Return txnh locked. Locks atom, if atom
+   is not NULL.  This performs the necessary spin_trylock to break the lock-ordering cycle.  May
+   return NULL. */
+static txn_atom *txnh_get_atom(txn_handle * txnh)
+{
+       txn_atom *atom;
+
+       assert("umka-180", txnh != NULL);
+       assert_spin_not_locked(&(txnh->hlock));
+
+       while (1) {
+               spin_lock_txnh(txnh);
+               atom = txnh->atom;
+
+               if (atom == NULL)
+                       break;
+
+               if (spin_trylock_atom(atom))
+                       break;
+
+               atomic_inc(&atom->refcount);
+
+               spin_unlock_txnh(txnh);
+               spin_lock_atom(atom);
+               spin_lock_txnh(txnh);
+
+               if (txnh->atom == atom) {
+                       atomic_dec(&atom->refcount);
+                       break;
+               }
+
+               spin_unlock_txnh(txnh);
+               atom_dec_and_unlock(atom);
+       }
+
+       return atom;
+}
+
+/* Get the current atom and spinlock it if current atom present. May return NULL  */
+txn_atom *get_current_atom_locked_nocheck(void)
+{
+       reiser4_context *cx;
+       txn_atom *atom;
+       txn_handle *txnh;
+
+       cx = get_current_context();
+       assert("zam-437", cx != NULL);
+
+       txnh = cx->trans;
+       assert("zam-435", txnh != NULL);
+
+       atom = txnh_get_atom(txnh);
+
+       spin_unlock_txnh(txnh);
+       return atom;
+}
+
+/* Get the atom belonging to a jnode, which is initially locked.  Return with
+   both jnode and atom locked.  This performs the necessary spin_trylock to
+   break the lock-ordering cycle.  Assumes the jnode is already locked, and
+   returns NULL if atom is not set. */
+txn_atom *jnode_get_atom(jnode * node)
+{
+       txn_atom *atom;
+
+       assert("umka-181", node != NULL);
+
+       while (1) {
+               assert_spin_locked(&(node->guard));
+
+               atom = node->atom;
+               /* node is not in any atom */
+               if (atom == NULL)
+                       break;
+
+               /* If atom is not locked, grab the lock and return */
+               if (spin_trylock_atom(atom))
+                       break;
+
+               /* At least one jnode belongs to this atom it guarantees that
+                * atom->refcount > 0, we can safely increment refcount. */
+               atomic_inc(&atom->refcount);
+               spin_unlock_jnode(node);
+
+               /* re-acquire spin locks in the right order */
+               spin_lock_atom(atom);
+               spin_lock_jnode(node);
+
+               /* check if node still points to the same atom. */
+               if (node->atom == atom) {
+                       atomic_dec(&atom->refcount);
+                       break;
+               }
+
+               /* releasing of atom lock and reference requires not holding
+                * locks on jnodes.  */
+               spin_unlock_jnode(node);
+
+               /* We do not sure that this atom has extra references except our
+                * one, so we should call proper function which may free atom if
+                * last reference is released. */
+               atom_dec_and_unlock(atom);
+
+               /* lock jnode again for getting valid node->atom pointer
+                * value. */
+               spin_lock_jnode(node);
+       }
+
+       return atom;
+}
+
+/* Returns true if @node is dirty and part of the same atom as one of its neighbors.  Used
+   by flush code to indicate whether the next node (in some direction) is suitable for
+   flushing. */
+int
+same_slum_check(jnode * node, jnode * check, int alloc_check, int alloc_value)
+{
+       int compat;
+       txn_atom *atom;
+
+       assert("umka-182", node != NULL);
+       assert("umka-183", check != NULL);
+
+       /* Not sure what this function is supposed to do if supplied with @check that is
+          neither formatted nor unformatted (bitmap or so). */
+       assert("nikita-2373", jnode_is_znode(check)
+              || jnode_is_unformatted(check));
+
+       /* Need a lock on CHECK to get its atom and to check various state bits.
+          Don't need a lock on NODE once we get the atom lock. */
+       /* It is not enough to lock two nodes and check (node->atom ==
+          check->atom) because atom could be locked and being fused at that
+          moment, jnodes of the atom of that state (being fused) can point to
+          different objects, but the atom is the same. */
+       spin_lock_jnode(check);
+
+       atom = jnode_get_atom(check);
+
+       if (atom == NULL) {
+               compat = 0;
+       } else {
+               compat = (node->atom == atom && JF_ISSET(check, JNODE_DIRTY));
+
+               if (compat && jnode_is_znode(check)) {
+                       compat &= znode_is_connected(JZNODE(check));
+               }
+
+               if (compat && alloc_check) {
+                       compat &= (alloc_value == jnode_is_flushprepped(check));
+               }
+
+               spin_unlock_atom(atom);
+       }
+
+       spin_unlock_jnode(check);
+
+       return compat;
+}
+
+/* Decrement the atom's reference count and if it falls to zero, free it. */
+void atom_dec_and_unlock(txn_atom * atom)
+{
+       txn_mgr *mgr = &get_super_private(reiser4_get_current_sb())->tmgr;
+
+       assert("umka-186", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+       assert("zam-1039", atomic_read(&atom->refcount) > 0);
+
+       if (atomic_dec_and_test(&atom->refcount)) {
+               /* take txnmgr lock and atom lock in proper order. */
+               if (!spin_trylock_txnmgr(mgr)) {
+                       /* This atom should exist after we re-acquire its
+                        * spinlock, so we increment its reference counter. */
+                       atomic_inc(&atom->refcount);
+                       spin_unlock_atom(atom);
+                       spin_lock_txnmgr(mgr);
+                       spin_lock_atom(atom);
+
+                       if (!atomic_dec_and_test(&atom->refcount)) {
+                               spin_unlock_atom(atom);
+                               spin_unlock_txnmgr(mgr);
+                               return;
+                       }
+               }
+               assert_spin_locked(&(mgr->tmgr_lock));
+               atom_free(atom);
+               spin_unlock_txnmgr(mgr);
+       } else
+               spin_unlock_atom(atom);
+}
+
+/* Create new atom and connect it to given transaction handle.  This adds the
+   atom to the transaction manager's list and sets its reference count to 1, an
+   artificial reference which is kept until it commits.  We play strange games
+   to avoid allocation under jnode & txnh spinlocks.*/
+
+static int atom_begin_and_assign_to_txnh(txn_atom ** atom_alloc, txn_handle * txnh)
+{
+       txn_atom *atom;
+       txn_mgr *mgr;
+
+       if (REISER4_DEBUG && rofs_tree(current_tree)) {
+               warning("nikita-3366", "Creating atom on rofs");
+               dump_stack();
+       }
+
+       if (*atom_alloc == NULL) {
+               (*atom_alloc) = kmem_cache_alloc(_atom_slab,
+                                                reiser4_ctx_gfp_mask_get());
+
+               if (*atom_alloc == NULL)
+                       return RETERR(-ENOMEM);
+       }
+
+       /* and, also, txnmgr spin lock should be taken before jnode and txnh
+          locks. */
+       mgr = &get_super_private(reiser4_get_current_sb())->tmgr;
+       spin_lock_txnmgr(mgr);
+       spin_lock_txnh(txnh);
+
+       /* Check whether new atom still needed */
+       if (txnh->atom != NULL) {
+               /* NOTE-NIKITA probably it is rather better to free
+                * atom_alloc here than thread it up to reiser4_try_capture() */
+
+               spin_unlock_txnh(txnh);
+               spin_unlock_txnmgr(mgr);
+
+               return -E_REPEAT;
+       }
+
+       atom = *atom_alloc;
+       *atom_alloc = NULL;
+
+       atom_init(atom);
+
+       assert("jmacd-17", atom_isclean(atom));
+
+        /*
+        * lock ordering is broken here. It is ok, as long as @atom is new
+        * and inaccessible for others. We can't use spin_lock_atom or
+        * spin_lock(&atom->alock) because they care about locking
+        * dependencies. spin_trylock_lock doesn't.
+        */
+       check_me("", spin_trylock_atom(atom));
+
+       /* add atom to the end of transaction manager's list of atoms */
+       list_add_tail(&atom->atom_link, &mgr->atoms_list);
+       atom->atom_id = mgr->id_count++;
+       mgr->atom_count += 1;
+
+       /* Release txnmgr lock */
+       spin_unlock_txnmgr(mgr);
+
+       /* One reference until it commits. */
+       atomic_inc(&atom->refcount);
+       atom->stage = ASTAGE_CAPTURE_FUSE;
+       atom->super = reiser4_get_current_sb();
+       capture_assign_txnh_nolock(atom, txnh);
+
+       spin_unlock_atom(atom);
+       spin_unlock_txnh(txnh);
+
+       return -E_REPEAT;
+}
+
+/* Return true if an atom is currently "open". */
+static int atom_isopen(const txn_atom * atom)
+{
+       assert("umka-185", atom != NULL);
+
+       return atom->stage > 0 && atom->stage < ASTAGE_PRE_COMMIT;
+}
+
+/* Return the number of pointers to this atom that must be updated during fusion.  This
+   approximates the amount of work to be done.  Fusion chooses the atom with fewer
+   pointers to fuse into the atom with more pointers. */
+static int atom_pointer_count(const txn_atom * atom)
+{
+       assert("umka-187", atom != NULL);
+
+       /* This is a measure of the amount of work needed to fuse this atom
+        * into another. */
+       return atom->txnh_count + atom->capture_count;
+}
+
+/* Called holding the atom lock, this removes the atom from the transaction manager list
+   and frees it. */
+static void atom_free(txn_atom * atom)
+{
+       txn_mgr *mgr = &get_super_private(reiser4_get_current_sb())->tmgr;
+
+       assert("umka-188", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       /* Remove from the txn_mgr's atom list */
+       assert_spin_locked(&(mgr->tmgr_lock));
+       mgr->atom_count -= 1;
+       list_del_init(&atom->atom_link);
+
+       /* Clean the atom */
+       assert("jmacd-16",
+              (atom->stage == ASTAGE_INVALID || atom->stage == ASTAGE_DONE));
+       atom->stage = ASTAGE_FREE;
+
+       blocknr_set_destroy(&atom->delete_set);
+       blocknr_set_destroy(&atom->wandered_map);
+
+       assert("jmacd-16", atom_isclean(atom));
+
+       spin_unlock_atom(atom);
+
+       kmem_cache_free(_atom_slab, atom);
+}
+
+static int atom_is_dotard(const txn_atom * atom)
+{
+       return time_after(jiffies, atom->start_time +
+                         get_current_super_private()->tmgr.atom_max_age);
+}
+
+static int atom_can_be_committed(txn_atom * atom)
+{
+       assert_spin_locked(&(atom->alock));
+       assert("zam-885", atom->txnh_count > atom->nr_waiters);
+       return atom->txnh_count == atom->nr_waiters + 1;
+}
+
+/* Return true if an atom should commit now.  This is determined by aging, atom
+   size or atom flags. */
+static int atom_should_commit(const txn_atom * atom)
+{
+       assert("umka-189", atom != NULL);
+       return
+           (atom->flags & ATOM_FORCE_COMMIT) ||
+           ((unsigned)atom_pointer_count(atom) >
+            get_current_super_private()->tmgr.atom_max_size)
+           || atom_is_dotard(atom);
+}
+
+/* return 1 if current atom exists and requires commit. */
+int current_atom_should_commit(void)
+{
+       txn_atom *atom;
+       int result = 0;
+
+       atom = get_current_atom_locked_nocheck();
+       if (atom) {
+               result = atom_should_commit(atom);
+               spin_unlock_atom(atom);
+       }
+       return result;
+}
+
+static int atom_should_commit_asap(const txn_atom * atom)
+{
+       unsigned int captured;
+       unsigned int pinnedpages;
+
+       assert("nikita-3309", atom != NULL);
+
+       captured = (unsigned)atom->capture_count;
+       pinnedpages = (captured >> PAGE_CACHE_SHIFT) * sizeof(znode);
+
+       return (pinnedpages > (totalram_pages >> 3)) || (atom->flushed > 100);
+}
+
+static jnode *find_first_dirty_in_list(struct list_head *head, int flags)
+{
+       jnode *first_dirty;
+
+       list_for_each_entry(first_dirty, head, capture_link) {
+               if (!(flags & JNODE_FLUSH_COMMIT)) {
+                       /*
+                        * skip jnodes which "heard banshee" or having active
+                        * I/O
+                        */
+                       if (JF_ISSET(first_dirty, JNODE_HEARD_BANSHEE) ||
+                           JF_ISSET(first_dirty, JNODE_WRITEBACK))
+                               continue;
+               }
+               return first_dirty;
+       }
+       return NULL;
+}
+
+/* Get first dirty node from the atom's dirty_nodes[n] lists; return NULL if atom has no dirty
+   nodes on atom's lists */
+jnode *find_first_dirty_jnode(txn_atom * atom, int flags)
+{
+       jnode *first_dirty;
+       tree_level level;
+
+       assert_spin_locked(&(atom->alock));
+
+       /* The flush starts from LEAF_LEVEL (=1). */
+       for (level = 1; level < REAL_MAX_ZTREE_HEIGHT + 1; level += 1) {
+               if (list_empty_careful(ATOM_DIRTY_LIST(atom, level)))
+                       continue;
+
+               first_dirty =
+                   find_first_dirty_in_list(ATOM_DIRTY_LIST(atom, level),
+                                            flags);
+               if (first_dirty)
+                       return first_dirty;
+       }
+
+       /* znode-above-root is on the list #0. */
+       return find_first_dirty_in_list(ATOM_DIRTY_LIST(atom, 0), flags);
+}
+
+static void dispatch_wb_list(txn_atom * atom, flush_queue_t * fq)
+{
+       jnode *cur;
+
+       assert("zam-905", atom_is_protected(atom));
+
+       cur = list_entry(ATOM_WB_LIST(atom)->next, jnode, capture_link);
+       while (ATOM_WB_LIST(atom) != &cur->capture_link) {
+               jnode *next = list_entry(cur->capture_link.next, jnode, capture_link);
+
+               spin_lock_jnode(cur);
+               if (!JF_ISSET(cur, JNODE_WRITEBACK)) {
+                       if (JF_ISSET(cur, JNODE_DIRTY)) {
+                               queue_jnode(fq, cur);
+                       } else {
+                               /* move jnode to atom's clean list */
+                               list_move_tail(&cur->capture_link,
+                                             ATOM_CLEAN_LIST(atom));
+                       }
+               }
+               spin_unlock_jnode(cur);
+
+               cur = next;
+       }
+}
+
+/* Scan current atom->writeback_nodes list, re-submit dirty and !writeback
+ * jnodes to disk. */
+static int submit_wb_list(void)
+{
+       int ret;
+       flush_queue_t *fq;
+
+       fq = get_fq_for_current_atom();
+       if (IS_ERR(fq))
+               return PTR_ERR(fq);
+
+       dispatch_wb_list(fq->atom, fq);
+       spin_unlock_atom(fq->atom);
+
+       ret = reiser4_write_fq(fq, NULL, 1);
+       reiser4_fq_put(fq);
+
+       return ret;
+}
+
+/* Wait completion of all writes, re-submit atom writeback list if needed. */
+static int current_atom_complete_writes(void)
+{
+       int ret;
+
+       /* Each jnode from that list was modified and dirtied when it had i/o
+        * request running already. After i/o completion we have to resubmit
+        * them to disk again.*/
+       ret = submit_wb_list();
+       if (ret < 0)
+               return ret;
+
+       /* Wait all i/o completion */
+       ret = current_atom_finish_all_fq();
+       if (ret)
+               return ret;
+
+       /* Scan wb list again; all i/o should be completed, we re-submit dirty
+        * nodes to disk */
+       ret = submit_wb_list();
+       if (ret < 0)
+               return ret;
+
+       /* Wait all nodes we just submitted */
+       return current_atom_finish_all_fq();
+}
+
+#if REISER4_DEBUG
+
+static void reiser4_info_atom(const char *prefix, const txn_atom * atom)
+{
+       if (atom == NULL) {
+               printk("%s: no atom\n", prefix);
+               return;
+       }
+
+       printk("%s: refcount: %i id: %i flags: %x txnh_count: %i"
+              " capture_count: %i stage: %x start: %lu, flushed: %i\n", prefix,
+              atomic_read(&atom->refcount), atom->atom_id, atom->flags,
+              atom->txnh_count, atom->capture_count, atom->stage,
+              atom->start_time, atom->flushed);
+}
+
+#else  /*  REISER4_DEBUG  */
+
+static inline void reiser4_info_atom(const char *prefix, const txn_atom * atom) {}
+
+#endif  /*  REISER4_DEBUG  */
+
+#define TOOMANYFLUSHES (1 << 13)
+
+/* Called with the atom locked and no open "active" transaction handlers except
+   ours, this function calls flush_current_atom() until all dirty nodes are
+   processed.  Then it initiates commit processing.
+
+   Called by the single remaining open "active" txnh, which is closing. Other
+   open txnhs belong to processes which wait atom commit in commit_txnh()
+   routine. They are counted as "waiters" in atom->nr_waiters.  Therefore as
+   long as we hold the atom lock none of the jnodes can be captured and/or
+   locked.
+
+   Return value is an error code if commit fails.
+*/
+static int commit_current_atom(long *nr_submitted, txn_atom ** atom)
+{
+       reiser4_super_info_data *sbinfo = get_current_super_private();
+       long ret = 0;
+       /* how many times jnode_flush() was called as a part of attempt to
+        * commit this atom. */
+       int flushiters;
+
+       assert("zam-888", atom != NULL && *atom != NULL);
+       assert_spin_locked(&((*atom)->alock));
+       assert("zam-887", get_current_context()->trans->atom == *atom);
+       assert("jmacd-151", atom_isopen(*atom));
+
+       assert("nikita-3184",
+              get_current_super_private()->delete_mutex_owner != current);
+
+       for (flushiters = 0;; ++flushiters) {
+               ret =
+                   flush_current_atom(JNODE_FLUSH_WRITE_BLOCKS |
+                                      JNODE_FLUSH_COMMIT,
+                                      LONG_MAX /* nr_to_write */ ,
+                                      nr_submitted, atom, NULL);
+               if (ret != -E_REPEAT)
+                       break;
+
+               /* if atom's dirty list contains one znode which is
+                  HEARD_BANSHEE and is locked we have to allow lock owner to
+                  continue and uncapture that znode */
+               reiser4_preempt_point();
+
+               *atom = get_current_atom_locked();
+               if (flushiters > TOOMANYFLUSHES && IS_POW(flushiters)) {
+                       warning("nikita-3176",
+                               "Flushing like mad: %i", flushiters);
+                       reiser4_info_atom("atom", *atom);
+                       DEBUGON(flushiters > (1 << 20));
+               }
+       }
+
+       if (ret)
+               return ret;
+
+       assert_spin_locked(&((*atom)->alock));
+
+       if (!atom_can_be_committed(*atom)) {
+               spin_unlock_atom(*atom);
+               return RETERR(-E_REPEAT);
+       }
+
+       if ((*atom)->capture_count == 0)
+               goto done;
+
+       /* Up to this point we have been flushing and after flush is called we
+          return -E_REPEAT.  Now we can commit.  We cannot return -E_REPEAT
+          at this point, commit should be successful. */
+       reiser4_atom_set_stage(*atom, ASTAGE_PRE_COMMIT);
+       ON_DEBUG(((*atom)->committer = current));
+       spin_unlock_atom(*atom);
+
+       ret = current_atom_complete_writes();
+       if (ret)
+               return ret;
+
+       assert("zam-906", list_empty(ATOM_WB_LIST(*atom)));
+
+       /* isolate critical code path which should be executed by only one
+        * thread using tmgr mutex */
+       mutex_lock(&sbinfo->tmgr.commit_mutex);
+
+       ret = reiser4_write_logs(nr_submitted);
+       if (ret < 0)
+               reiser4_panic("zam-597", "write log failed (%ld)\n", ret);
+
+       /* The atom->ovrwr_nodes list is processed under commit mutex held
+          because of bitmap nodes which are captured by special way in
+          reiser4_pre_commit_hook_bitmap(), that way does not include
+          capture_fuse_wait() as a capturing of other nodes does -- the commit
+          mutex is used for transaction isolation instead. */
+       reiser4_invalidate_list(ATOM_OVRWR_LIST(*atom));
+       mutex_unlock(&sbinfo->tmgr.commit_mutex);
+
+       reiser4_invalidate_list(ATOM_CLEAN_LIST(*atom));
+       reiser4_invalidate_list(ATOM_WB_LIST(*atom));
+       assert("zam-927", list_empty(&(*atom)->inodes));
+
+       spin_lock_atom(*atom);
+ done:
+       reiser4_atom_set_stage(*atom, ASTAGE_DONE);
+       ON_DEBUG((*atom)->committer = NULL);
+
+       /* Atom's state changes, so wake up everybody waiting for this
+          event. */
+       wakeup_atom_waiting_list(*atom);
+
+       /* Decrement the "until commit" reference, at least one txnh (the caller) is
+          still open. */
+       atomic_dec(&(*atom)->refcount);
+
+       assert("jmacd-1070", atomic_read(&(*atom)->refcount) > 0);
+       assert("jmacd-1062", (*atom)->capture_count == 0);
+       BUG_ON((*atom)->capture_count != 0);
+       assert_spin_locked(&((*atom)->alock));
+
+       return ret;
+}
+
+/* TXN_TXNH */
+
+/**
+ * force_commit_atom - commit current atom and wait commit completion
+ * @txnh:
+ *
+ * Commits current atom and wait commit completion; current atom and @txnh have
+ * to be spinlocked before call, this function unlocks them on exit.
+ */
+int force_commit_atom(txn_handle *txnh)
+{
+       txn_atom *atom;
+
+       assert("zam-837", txnh != NULL);
+       assert_spin_locked(&(txnh->hlock));
+       assert("nikita-2966", lock_stack_isclean(get_current_lock_stack()));
+
+       atom = txnh->atom;
+
+       assert("zam-834", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       /*
+        * Set flags for atom and txnh: forcing atom commit and waiting for
+        * commit completion
+        */
+       txnh->flags |= TXNH_WAIT_COMMIT;
+       atom->flags |= ATOM_FORCE_COMMIT;
+
+       spin_unlock_txnh(txnh);
+       spin_unlock_atom(atom);
+
+       /* commit is here */
+       reiser4_txn_restart_current();
+       return 0;
+}
+
+/* Called to force commit of any outstanding atoms.  @commit_all_atoms controls
+ * should we commit all atoms including new ones which are created after this
+ * functions is called. */
+int txnmgr_force_commit_all(struct super_block *super, int commit_all_atoms)
+{
+       int ret;
+       txn_atom *atom;
+       txn_mgr *mgr;
+       txn_handle *txnh;
+       unsigned long start_time = jiffies;
+       reiser4_context *ctx = get_current_context();
+
+       assert("nikita-2965", lock_stack_isclean(get_current_lock_stack()));
+       assert("nikita-3058", reiser4_commit_check_locks());
+
+       reiser4_txn_restart_current();
+
+       mgr = &get_super_private(super)->tmgr;
+
+       txnh = ctx->trans;
+
+      again:
+
+       spin_lock_txnmgr(mgr);
+
+       list_for_each_entry(atom, &mgr->atoms_list, atom_link) {
+               spin_lock_atom(atom);
+
+               /* Commit any atom which can be committed.  If @commit_new_atoms
+                * is not set we commit only atoms which were created before
+                * this call is started. */
+               if (commit_all_atoms
+                   || time_before_eq(atom->start_time, start_time)) {
+                       if (atom->stage <= ASTAGE_POST_COMMIT) {
+                               spin_unlock_txnmgr(mgr);
+
+                               if (atom->stage < ASTAGE_PRE_COMMIT) {
+                                       spin_lock_txnh(txnh);
+                                       /* Add force-context txnh */
+                                       capture_assign_txnh_nolock(atom, txnh);
+                                       ret = force_commit_atom(txnh);
+                                       if (ret)
+                                               return ret;
+                               } else
+                                       /* wait atom commit */
+                                       reiser4_atom_wait_event(atom);
+
+                               goto again;
+                       }
+               }
+
+               spin_unlock_atom(atom);
+       }
+
+#if REISER4_DEBUG
+       if (commit_all_atoms) {
+               reiser4_super_info_data *sbinfo = get_super_private(super);
+               spin_lock_reiser4_super(sbinfo);
+               assert("zam-813",
+                      sbinfo->blocks_fake_allocated_unformatted == 0);
+               assert("zam-812", sbinfo->blocks_fake_allocated == 0);
+               spin_unlock_reiser4_super(sbinfo);
+       }
+#endif
+
+       spin_unlock_txnmgr(mgr);
+
+       return 0;
+}
+
+/* check whether commit_some_atoms() can commit @atom. Locking is up to the
+ * caller */
+static int atom_is_committable(txn_atom * atom)
+{
+       return
+           atom->stage < ASTAGE_PRE_COMMIT &&
+           atom->txnh_count == atom->nr_waiters && atom_should_commit(atom);
+}
+
+/* called periodically from ktxnmgrd to commit old atoms. Releases ktxnmgrd spin
+ * lock at exit */
+int commit_some_atoms(txn_mgr * mgr)
+{
+       int ret = 0;
+       txn_atom *atom;
+       txn_handle *txnh;
+       reiser4_context *ctx;
+       struct list_head *pos, *tmp;
+
+       ctx = get_current_context();
+       assert("nikita-2444", ctx != NULL);
+
+       txnh = ctx->trans;
+       spin_lock_txnmgr(mgr);
+
+       /*
+        * this is to avoid gcc complain that atom might be used
+        * uninitialized
+        */
+       atom = NULL;
+
+       /* look for atom to commit */
+       list_for_each_safe(pos, tmp, &mgr->atoms_list) {
+               atom = list_entry(pos, txn_atom, atom_link);
+               /*
+                * first test without taking atom spin lock, whether it is
+                * eligible for committing at all
+                */
+               if (atom_is_committable(atom)) {
+                       /* now, take spin lock and re-check */
+                       spin_lock_atom(atom);
+                       if (atom_is_committable(atom))
+                               break;
+                       spin_unlock_atom(atom);
+               }
+       }
+
+       ret = (&mgr->atoms_list == pos);
+       spin_unlock_txnmgr(mgr);
+
+       if (ret) {
+               /* nothing found */
+               spin_unlock(&mgr->daemon->guard);
+               return 0;
+       }
+
+       spin_lock_txnh(txnh);
+
+       BUG_ON(atom == NULL);
+       /* Set the atom to force committing */
+       atom->flags |= ATOM_FORCE_COMMIT;
+
+       /* Add force-context txnh */
+       capture_assign_txnh_nolock(atom, txnh);
+
+       spin_unlock_txnh(txnh);
+       spin_unlock_atom(atom);
+
+       /* we are about to release daemon spin lock, notify daemon it
+          has to rescan atoms */
+       mgr->daemon->rescan = 1;
+       spin_unlock(&mgr->daemon->guard);
+       reiser4_txn_restart_current();
+       return 0;
+}
+
+static int txn_try_to_fuse_small_atom(txn_mgr * tmgr, txn_atom * atom)
+{
+       int atom_stage;
+       txn_atom *atom_2;
+       int repeat;
+
+       assert("zam-1051", atom->stage < ASTAGE_PRE_COMMIT);
+
+       atom_stage = atom->stage;
+       repeat = 0;
+
+       if (!spin_trylock_txnmgr(tmgr)) {
+               atomic_inc(&atom->refcount);
+               spin_unlock_atom(atom);
+               spin_lock_txnmgr(tmgr);
+               spin_lock_atom(atom);
+               repeat = 1;
+               if (atom->stage != atom_stage) {
+                       spin_unlock_txnmgr(tmgr);
+                       atom_dec_and_unlock(atom);
+                       return -E_REPEAT;
+               }
+               atomic_dec(&atom->refcount);
+       }
+
+       list_for_each_entry(atom_2, &tmgr->atoms_list, atom_link) {
+               if (atom == atom_2)
+                       continue;
+               /*
+                * if trylock does not succeed we just do not fuse with that
+                * atom.
+                */
+               if (spin_trylock_atom(atom_2)) {
+                       if (atom_2->stage < ASTAGE_PRE_COMMIT) {
+                               spin_unlock_txnmgr(tmgr);
+                               capture_fuse_into(atom_2, atom);
+                               /* all locks are lost we can only repeat here */
+                               return -E_REPEAT;
+                       }
+                       spin_unlock_atom(atom_2);
+               }
+       }
+       atom->flags |= ATOM_CANCEL_FUSION;
+       spin_unlock_txnmgr(tmgr);
+       if (repeat) {
+               spin_unlock_atom(atom);
+               return -E_REPEAT;
+       }
+       return 0;
+}
+
+/* Calls jnode_flush for current atom if it exists; if not, just take another
+   atom and call jnode_flush() for him.  If current transaction handle has
+   already assigned atom (current atom) we have to close current transaction
+   prior to switch to another atom or do something with current atom. This
+   code tries to flush current atom.
+
+   flush_some_atom() is called as part of memory clearing process. It is
+   invoked from balance_dirty_pages(), pdflushd, and entd.
+
+   If we can flush no nodes, atom is committed, because this frees memory.
+
+   If atom is too large or too old it is committed also.
+*/
+int
+flush_some_atom(jnode * start, long *nr_submitted, const struct writeback_control *wbc,
+               int flags)
+{
+       reiser4_context *ctx = get_current_context();
+       txn_mgr *tmgr = &get_super_private(ctx->super)->tmgr;
+       txn_handle *txnh = ctx->trans;
+       txn_atom *atom;
+       int ret;
+
+       BUG_ON(wbc->nr_to_write == 0);
+       BUG_ON(*nr_submitted != 0);
+       assert("zam-1042", txnh != NULL);
+      repeat:
+       if (txnh->atom == NULL) {
+               /* current atom is not available, take first from txnmgr */
+               spin_lock_txnmgr(tmgr);
+
+               /* traverse the list of all atoms */
+               list_for_each_entry(atom, &tmgr->atoms_list, atom_link) {
+                       /* lock atom before checking its state */
+                       spin_lock_atom(atom);
+
+                       /*
+                        * we need an atom which is not being committed and
+                        * which has no flushers (jnode_flush() add one flusher
+                        * at the beginning and subtract one at the end).
+                        */
+                       if (atom->stage < ASTAGE_PRE_COMMIT &&
+                           atom->nr_flushers == 0) {
+                               spin_lock_txnh(txnh);
+                               capture_assign_txnh_nolock(atom, txnh);
+                               spin_unlock_txnh(txnh);
+
+                               goto found;
+                       }
+
+                       spin_unlock_atom(atom);
+               }
+
+               /*
+                * Write throttling is case of no one atom can be
+                * flushed/committed.
+                */
+               if (!current_is_pdflush() && !wbc->nonblocking) {
+                       list_for_each_entry(atom, &tmgr->atoms_list, atom_link) {
+                               spin_lock_atom(atom);
+                               /* Repeat the check from the above. */
+                               if (atom->stage < ASTAGE_PRE_COMMIT
+                                   && atom->nr_flushers == 0) {
+                                       spin_lock_txnh(txnh);
+                                       capture_assign_txnh_nolock(atom, txnh);
+                                       spin_unlock_txnh(txnh);
+
+                                       goto found;
+                               }
+                               if (atom->stage <= ASTAGE_POST_COMMIT) {
+                                       spin_unlock_txnmgr(tmgr);
+                                       /*
+                                        * we just wait until atom's flusher
+                                        * makes a progress in flushing or
+                                        * committing the atom
+                                        */
+                                       reiser4_atom_wait_event(atom);
+                                       goto repeat;
+                               }
+                               spin_unlock_atom(atom);
+                       }
+               }
+               spin_unlock_txnmgr(tmgr);
+               return 0;
+             found:
+               spin_unlock_txnmgr(tmgr);
+       } else
+               atom = get_current_atom_locked();
+
+       BUG_ON(atom->super != ctx->super);
+       assert("vs-35", atom->super == ctx->super);
+       if (start) {
+               spin_lock_jnode(start);
+               ret = (atom == start->atom) ? 1 : 0;
+               spin_unlock_jnode(start);
+               if (ret == 0)
+                       start = NULL;
+       }
+       ret = flush_current_atom(flags, wbc->nr_to_write, nr_submitted, &atom, start);
+       if (ret == 0) {
+               /* flush_current_atom returns 0 only if it submitted for write
+                  nothing */
+               BUG_ON(*nr_submitted != 0);
+               if (*nr_submitted == 0 || atom_should_commit_asap(atom)) {
+                       if (atom->capture_count < tmgr->atom_min_size &&
+                           !(atom->flags & ATOM_CANCEL_FUSION)) {
+                               ret = txn_try_to_fuse_small_atom(tmgr, atom);
+                               if (ret == -E_REPEAT) {
+                                       reiser4_preempt_point();
+                                       goto repeat;
+                               }
+                       }
+                       /* if early flushing could not make more nodes clean,
+                        * or atom is too old/large,
+                        * we force current atom to commit */
+                       /* wait for commit completion but only if this
+                        * wouldn't stall pdflushd and ent thread. */
+                       if (!wbc->nonblocking && !ctx->entd)
+                               txnh->flags |= TXNH_WAIT_COMMIT;
+                       atom->flags |= ATOM_FORCE_COMMIT;
+               }
+               spin_unlock_atom(atom);
+       } else if (ret == -E_REPEAT) {
+               if (*nr_submitted == 0) {
+                       /* let others who hampers flushing (hold longterm locks,
+                          for instance) to free the way for flush */
+                       reiser4_preempt_point();
+                       goto repeat;
+               }
+               ret = 0;
+       }
+/*
+       if (*nr_submitted > wbc->nr_to_write)
+               warning("", "asked for %ld, written %ld\n", wbc->nr_to_write, *nr_submitted);
+*/
+       reiser4_txn_restart(ctx);
+
+       return ret;
+}
+
+/* Remove processed nodes from atom's clean list (thereby remove them from transaction). */
+void reiser4_invalidate_list(struct list_head *head)
+{
+       while (!list_empty(head)) {
+               jnode *node;
+
+               node = list_entry(head->next, jnode, capture_link);
+               spin_lock_jnode(node);
+               reiser4_uncapture_block(node);
+               jput(node);
+       }
+}
+
+static void init_wlinks(txn_wait_links * wlinks)
+{
+       wlinks->_lock_stack = get_current_lock_stack();
+       INIT_LIST_HEAD(&wlinks->_fwaitfor_link);
+       INIT_LIST_HEAD(&wlinks->_fwaiting_link);
+       wlinks->waitfor_cb = NULL;
+       wlinks->waiting_cb = NULL;
+}
+
+/* Add atom to the atom's waitfor list and wait for somebody to wake us up; */
+void reiser4_atom_wait_event(txn_atom * atom)
+{
+       txn_wait_links _wlinks;
+
+       assert_spin_locked(&(atom->alock));
+       assert("nikita-3156",
+              lock_stack_isclean(get_current_lock_stack()) ||
+              atom->nr_running_queues > 0);
+
+       init_wlinks(&_wlinks);
+       list_add_tail(&_wlinks._fwaitfor_link, &atom->fwaitfor_list);
+       atomic_inc(&atom->refcount);
+       spin_unlock_atom(atom);
+
+       reiser4_prepare_to_sleep(_wlinks._lock_stack);
+       reiser4_go_to_sleep(_wlinks._lock_stack);
+
+       spin_lock_atom(atom);
+       list_del(&_wlinks._fwaitfor_link);
+       atom_dec_and_unlock(atom);
+}
+
+void reiser4_atom_set_stage(txn_atom * atom, txn_stage stage)
+{
+       assert("nikita-3535", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+       assert("nikita-3536", stage <= ASTAGE_INVALID);
+       /* Excelsior! */
+       assert("nikita-3537", stage >= atom->stage);
+       if (atom->stage != stage) {
+               atom->stage = stage;
+               reiser4_atom_send_event(atom);
+       }
+}
+
+/* wake all threads which wait for an event */
+void reiser4_atom_send_event(txn_atom * atom)
+{
+       assert_spin_locked(&(atom->alock));
+       wakeup_atom_waitfor_list(atom);
+}
+
+/* Informs txn manager code that owner of this txn_handle should wait atom commit completion (for
+   example, because it does fsync(2)) */
+static int should_wait_commit(txn_handle * h)
+{
+       return h->flags & TXNH_WAIT_COMMIT;
+}
+
+typedef struct commit_data {
+       txn_atom *atom;
+       txn_handle *txnh;
+       long nr_written;
+       /* as an optimization we start committing atom by first trying to
+        * flush it few times without switching into ASTAGE_CAPTURE_WAIT. This
+        * allows to reduce stalls due to other threads waiting for atom in
+        * ASTAGE_CAPTURE_WAIT stage. ->preflush is counter of these
+        * preliminary flushes. */
+       int preflush;
+       /* have we waited on atom. */
+       int wait;
+       int failed;
+       int wake_ktxnmgrd_up;
+} commit_data;
+
+/*
+ * Called from commit_txnh() repeatedly, until either error happens, or atom
+ * commits successfully.
+ */
+static int try_commit_txnh(commit_data * cd)
+{
+       int result;
+
+       assert("nikita-2968", lock_stack_isclean(get_current_lock_stack()));
+
+       /* Get the atom and txnh locked. */
+       cd->atom = txnh_get_atom(cd->txnh);
+       assert("jmacd-309", cd->atom != NULL);
+       spin_unlock_txnh(cd->txnh);
+
+       if (cd->wait) {
+               cd->atom->nr_waiters--;
+               cd->wait = 0;
+       }
+
+       if (cd->atom->stage == ASTAGE_DONE)
+               return 0;
+
+       if (cd->failed)
+               return 0;
+
+       if (atom_should_commit(cd->atom)) {
+               /* if atom is _very_ large schedule it for commit as soon as
+                * possible. */
+               if (atom_should_commit_asap(cd->atom)) {
+                       /*
+                        * When atom is in PRE_COMMIT or later stage following
+                        * invariant (encoded   in    atom_can_be_committed())
+                        * holds:  there is exactly one non-waiter transaction
+                        * handle opened  on this atom.  When  thread wants to
+                        * wait  until atom  commits (for  example  sync()) it
+                        * waits    on    atom  event     after     increasing
+                        * atom->nr_waiters (see blow  in  this  function). It
+                        * cannot be guaranteed that atom is already committed
+                        * after    receiving event,  so     loop has   to  be
+                        * re-started. But  if  atom switched into  PRE_COMMIT
+                        * stage and became  too  large, we cannot  change its
+                        * state back   to CAPTURE_WAIT (atom  stage can  only
+                        * increase monotonically), hence this check.
+                        */
+                       if (cd->atom->stage < ASTAGE_CAPTURE_WAIT)
+                               reiser4_atom_set_stage(cd->atom,
+                                                      ASTAGE_CAPTURE_WAIT);
+                       cd->atom->flags |= ATOM_FORCE_COMMIT;
+               }
+               if (cd->txnh->flags & TXNH_DONT_COMMIT) {
+                       /*
+                        * this  thread (transaction  handle  that is) doesn't
+                        * want to commit  atom. Notify waiters that handle is
+                        * closed. This can happen, for  example, when we  are
+                        * under  VFS directory lock  and don't want to commit
+                        * atom  right   now to  avoid  stalling other threads
+                        * working in the same directory.
+                        */
+
+                       /* Wake  the ktxnmgrd up if  the ktxnmgrd is needed to
+                        * commit this  atom: no  atom  waiters  and only  one
+                        * (our) open transaction handle. */
+                       cd->wake_ktxnmgrd_up =
+                           cd->atom->txnh_count == 1 &&
+                           cd->atom->nr_waiters == 0;
+                       reiser4_atom_send_event(cd->atom);
+                       result = 0;
+               } else if (!atom_can_be_committed(cd->atom)) {
+                       if (should_wait_commit(cd->txnh)) {
+                               /* sync(): wait for commit */
+                               cd->atom->nr_waiters++;
+                               cd->wait = 1;
+                               reiser4_atom_wait_event(cd->atom);
+                               result = RETERR(-E_REPEAT);
+                       } else {
+                               result = 0;
+                       }
+               } else if (cd->preflush > 0 && !is_current_ktxnmgrd()) {
+                       /*
+                        * optimization: flush  atom without switching it into
+                        * ASTAGE_CAPTURE_WAIT.
+                        *
+                        * But don't  do this for  ktxnmgrd, because  ktxnmgrd
+                        * should never block on atom fusion.
+                        */
+                       result = flush_current_atom(JNODE_FLUSH_WRITE_BLOCKS,
+                                                   LONG_MAX, &cd->nr_written,
+                                                   &cd->atom, NULL);
+                       if (result == 0) {
+                               spin_unlock_atom(cd->atom);
+                               cd->preflush = 0;
+                               result = RETERR(-E_REPEAT);
+                       } else  /* Atoms wasn't flushed
+                                * completely. Rinse. Repeat. */
+                               --cd->preflush;
+               } else {
+                       /* We change   atom state  to   ASTAGE_CAPTURE_WAIT to
+                          prevent atom fusion and count  ourself as an active
+                          flusher */
+                       reiser4_atom_set_stage(cd->atom, ASTAGE_CAPTURE_WAIT);
+                       cd->atom->flags |= ATOM_FORCE_COMMIT;
+
+                       result =
+                           commit_current_atom(&cd->nr_written, &cd->atom);
+                       if (result != 0 && result != -E_REPEAT)
+                               cd->failed = 1;
+               }
+       } else
+               result = 0;
+
+#if REISER4_DEBUG
+       if (result == 0)
+               assert_spin_locked(&(cd->atom->alock));
+#endif
+
+       /* perfectly valid assertion, except that when atom/txnh is not locked
+        * fusion can take place, and cd->atom points nowhere. */
+       /*
+          assert("jmacd-1028", ergo(result != 0, spin_atom_is_not_locked(cd->atom)));
+        */
+       return result;
+}
+
+/* Called to commit a transaction handle.  This decrements the atom's number of open
+   handles and if it is the last handle to commit and the atom should commit, initiates
+   atom commit. if commit does not fail, return number of written blocks */
+static int commit_txnh(txn_handle * txnh)
+{
+       commit_data cd;
+       assert("umka-192", txnh != NULL);
+
+       memset(&cd, 0, sizeof cd);
+       cd.txnh = txnh;
+       cd.preflush = 10;
+
+       /* calls try_commit_txnh() until either atom commits, or error
+        * happens */
+       while (try_commit_txnh(&cd) != 0)
+               reiser4_preempt_point();
+
+       spin_lock_txnh(txnh);
+
+       cd.atom->txnh_count -= 1;
+       txnh->atom = NULL;
+       /* remove transaction handle from atom's list of transaction handles */
+       list_del_init(&txnh->txnh_link);
+
+       spin_unlock_txnh(txnh);
+       atom_dec_and_unlock(cd.atom);
+       /* if we don't want to do a commit (TXNH_DONT_COMMIT is set, probably
+        * because it takes time) by current thread, we do that work
+        * asynchronously by ktxnmgrd daemon. */
+       if (cd.wake_ktxnmgrd_up)
+               ktxnmgrd_kick(&get_current_super_private()->tmgr);
+
+       return 0;
+}
+
+/* TRY_CAPTURE */
+
+/* This routine attempts a single block-capture request.  It may return -E_REPEAT if some
+   condition indicates that the request should be retried, and it may block if the
+   txn_capture mode does not include the TXN_CAPTURE_NONBLOCKING request flag.
+
+   This routine encodes the basic logic of block capturing described by:
+
+     http://namesys.com/v4/v4.html
+
+   Our goal here is to ensure that any two blocks that contain dependent modifications
+   should commit at the same time.  This function enforces this discipline by initiating
+   fusion whenever a transaction handle belonging to one atom requests to read or write a
+   block belonging to another atom (TXN_CAPTURE_WRITE or TXN_CAPTURE_READ_ATOMIC).
+
+   In addition, this routine handles the initial assignment of atoms to blocks and
+   transaction handles.  These are possible outcomes of this function:
+
+   1. The block and handle are already part of the same atom: return immediate success
+
+   2. The block is assigned but the handle is not: call capture_assign_txnh to assign
+      the handle to the block's atom.
+
+   3. The handle is assigned but the block is not: call capture_assign_block to assign
+      the block to the handle's atom.
+
+   4. Both handle and block are assigned, but to different atoms: call capture_init_fusion
+      to fuse atoms.
+
+   5. Neither block nor handle are assigned: create a new atom and assign them both.
+
+   6. A read request for a non-captured block: return immediate success.
+
+   This function acquires and releases the handle's spinlock.  This function is called
+   under the jnode lock and if the return value is 0, it returns with the jnode lock still
+   held.  If the return is -E_REPEAT or some other error condition, the jnode lock is
+   released.  The external interface (reiser4_try_capture) manages re-aquiring the jnode
+   lock in the failure case.
+*/
+static int try_capture_block(
+       txn_handle * txnh, jnode * node, txn_capture mode,
+       txn_atom ** atom_alloc)
+{
+       txn_atom *block_atom;
+       txn_atom *txnh_atom;
+
+       /* Should not call capture for READ_NONCOM requests, handled in reiser4_try_capture. */
+       assert("jmacd-567", CAPTURE_TYPE(mode) != TXN_CAPTURE_READ_NONCOM);
+
+       /* FIXME-ZAM-HANS: FIXME_LATER_JMACD Should assert that atom->tree ==
+        * node->tree somewhere. */
+       assert("umka-194", txnh != NULL);
+       assert("umka-195", node != NULL);
+
+       /* The jnode is already locked!  Being called from reiser4_try_capture(). */
+       assert_spin_locked(&(node->guard));
+       block_atom = node->atom;
+
+       /* Get txnh spinlock, this allows us to compare txn_atom pointers but it doesn't
+          let us touch the atoms themselves. */
+       spin_lock_txnh(txnh);
+       txnh_atom = txnh->atom;
+       /* Process of capturing continues into one of four branches depends on
+          which atoms from (block atom (node->atom), current atom (txnh->atom))
+          exist. */
+       if (txnh_atom == NULL) {
+               if (block_atom == NULL) {
+                       spin_unlock_txnh(txnh);
+                       spin_unlock_jnode(node);
+                       /* assign empty atom to the txnh and repeat */
+                       return atom_begin_and_assign_to_txnh(atom_alloc, txnh);
+               } else {
+                       atomic_inc(&block_atom->refcount);
+                       /* node spin-lock isn't needed anymore */
+                       spin_unlock_jnode(node);
+                       if (!spin_trylock_atom(block_atom)) {
+                               spin_unlock_txnh(txnh);
+                               spin_lock_atom(block_atom);
+                               spin_lock_txnh(txnh);
+                       }
+                       /* re-check state after getting txnh and the node
+                        * atom spin-locked */
+                       if (node->atom != block_atom || txnh->atom != NULL) {
+                               spin_unlock_txnh(txnh);
+                               atom_dec_and_unlock(block_atom);
+                               return RETERR(-E_REPEAT);
+                       }
+                       atomic_dec(&block_atom->refcount);
+                       if (block_atom->stage > ASTAGE_CAPTURE_WAIT ||
+                           (block_atom->stage == ASTAGE_CAPTURE_WAIT &&
+                            block_atom->txnh_count != 0))
+                               return capture_fuse_wait(txnh, block_atom, NULL, mode);
+                       capture_assign_txnh_nolock(block_atom, txnh);
+                       spin_unlock_txnh(txnh);
+                       spin_unlock_atom(block_atom);
+                       return RETERR(-E_REPEAT);
+               }
+       } else {
+               /* It is time to perform deadlock prevention check over the
+                  node we want to capture.  It is possible this node was locked
+                  for read without capturing it. The optimization which allows
+                  to do it helps us in keeping atoms independent as long as
+                  possible but it may cause lock/fuse deadlock problems.
+
+                  A number of similar deadlock situations with locked but not
+                  captured nodes were found.  In each situation there are two
+                  or more threads: one of them does flushing while another one
+                  does routine balancing or tree lookup.  The flushing thread
+                  (F) sleeps in long term locking request for node (N), another
+                  thread (A) sleeps in trying to capture some node already
+                  belonging the atom F, F has a state which prevents
+                  immediately fusion .
+
+                  Deadlocks of this kind cannot happen if node N was properly
+                  captured by thread A. The F thread fuse atoms before locking
+                  therefore current atom of thread F and current atom of thread
+                  A became the same atom and thread A may proceed.  This does
+                  not work if node N was not captured because the fusion of
+                  atom does not happens.
+
+                  The following scheme solves the deadlock: If
+                  longterm_lock_znode locks and does not capture a znode, that
+                  znode is marked as MISSED_IN_CAPTURE.  A node marked this way
+                  is processed by the code below which restores the missed
+                  capture and fuses current atoms of all the node lock owners
+                  by calling the fuse_not_fused_lock_owners() function. */
+               if (JF_ISSET(node, JNODE_MISSED_IN_CAPTURE)) {
+                       JF_CLR(node, JNODE_MISSED_IN_CAPTURE);
+                       if (jnode_is_znode(node) && znode_is_locked(JZNODE(node))) {
+                               spin_unlock_txnh(txnh);
+                               spin_unlock_jnode(node);
+                               fuse_not_fused_lock_owners(txnh, JZNODE(node));
+                               return RETERR(-E_REPEAT);
+                       }
+               }
+               if (block_atom == NULL) {
+                       atomic_inc(&txnh_atom->refcount);
+                       spin_unlock_txnh(txnh);
+                       if (!spin_trylock_atom(txnh_atom)) {
+                               spin_unlock_jnode(node);
+                               spin_lock_atom(txnh_atom);
+                               spin_lock_jnode(node);
+                       }
+                       if (txnh->atom != txnh_atom || node->atom != NULL
+                               || JF_ISSET(node, JNODE_IS_DYING)) {
+                               spin_unlock_jnode(node);
+                               atom_dec_and_unlock(txnh_atom);
+                               return RETERR(-E_REPEAT);
+                       }
+                       atomic_dec(&txnh_atom->refcount);
+                       capture_assign_block_nolock(txnh_atom, node);
+                       spin_unlock_atom(txnh_atom);
+               } else {
+                       if (txnh_atom != block_atom) {
+                               if (mode & TXN_CAPTURE_DONT_FUSE) {
+                                       spin_unlock_txnh(txnh);
+                                       spin_unlock_jnode(node);
+                                       /* we are in a "no-fusion" mode and @node is
+                                        * already part of transaction. */
+                                       return RETERR(-E_NO_NEIGHBOR);
+                               }
+                               return capture_init_fusion(node, txnh, mode);
+                       }
+                       spin_unlock_txnh(txnh);
+               }
+       }
+       return 0;
+}
+
+static txn_capture
+build_capture_mode(jnode * node, znode_lock_mode lock_mode, txn_capture flags)
+{
+       txn_capture cap_mode;
+
+       assert_spin_locked(&(node->guard));
+
+       /* FIXME_JMACD No way to set TXN_CAPTURE_READ_MODIFY yet. */
+
+       if (lock_mode == ZNODE_WRITE_LOCK) {
+               cap_mode = TXN_CAPTURE_WRITE;
+       } else if (node->atom != NULL) {
+               cap_mode = TXN_CAPTURE_WRITE;
+       } else if (0 &&         /* txnh->mode == TXN_READ_FUSING && */
+                  jnode_get_level(node) == LEAF_LEVEL) {
+               /* NOTE-NIKITA TXN_READ_FUSING is not currently used */
+               /* We only need a READ_FUSING capture at the leaf level.  This
+                  is because the internal levels of the tree (twigs included)
+                  are redundant from the point of the user that asked for a
+                  read-fusing transcrash.  The user only wants to read-fuse
+                  atoms due to reading uncommitted data that another user has
+                  written.  It is the file system that reads/writes the
+                  internal tree levels, the user only reads/writes leaves. */
+               cap_mode = TXN_CAPTURE_READ_ATOMIC;
+       } else {
+               /* In this case (read lock at a non-leaf) there's no reason to
+                * capture. */
+               /* cap_mode = TXN_CAPTURE_READ_NONCOM; */
+               return 0;
+       }
+
+       cap_mode |= (flags & (TXN_CAPTURE_NONBLOCKING | TXN_CAPTURE_DONT_FUSE));
+       assert("nikita-3186", cap_mode != 0);
+       return cap_mode;
+}
+
+/* This is an external interface to try_capture_block(), it calls
+   try_capture_block() repeatedly as long as -E_REPEAT is returned.
+
+   @node:         node to capture,
+   @lock_mode:    read or write lock is used in capture mode calculation,
+   @flags:        see txn_capture flags enumeration,
+   @can_coc     : can copy-on-capture
+
+   @return: 0 - node was successfully captured, -E_REPEAT - capture request
+            cannot be processed immediately as it was requested in flags,
+           < 0 - other errors.
+*/
+int reiser4_try_capture(jnode *node, znode_lock_mode lock_mode,
+                       txn_capture flags)
+{
+       txn_atom *atom_alloc = NULL;
+       txn_capture cap_mode;
+       txn_handle *txnh = get_current_context()->trans;
+       int ret;
+
+       assert_spin_locked(&(node->guard));
+
+      repeat:
+       if (JF_ISSET(node, JNODE_IS_DYING))
+               return RETERR(-EINVAL);
+       if (node->atom != NULL && txnh->atom == node->atom)
+               return 0;
+       cap_mode = build_capture_mode(node, lock_mode, flags);
+       if (cap_mode == 0 ||
+           (!(cap_mode & TXN_CAPTURE_WTYPES) && node->atom == NULL)) {
+               /* Mark this node as "MISSED".  It helps in further deadlock
+                * analysis */
+               if (jnode_is_znode(node))
+                       JF_SET(node, JNODE_MISSED_IN_CAPTURE);
+               return 0;
+       }
+       /* Repeat try_capture as long as -E_REPEAT is returned. */
+       ret = try_capture_block(txnh, node, cap_mode, &atom_alloc);
+       /* Regardless of non_blocking:
+
+          If ret == 0 then jnode is still locked.
+          If ret != 0 then jnode is unlocked.
+        */
+#if REISER4_DEBUG
+       if (ret == 0)
+               assert_spin_locked(&(node->guard));
+       else
+               assert_spin_not_locked(&(node->guard));
+#endif
+       assert_spin_not_locked(&(txnh->guard));
+
+       if (ret == -E_REPEAT) {
+               /* E_REPEAT implies all locks were released, therefore we need
+                  to take the jnode's lock again. */
+               spin_lock_jnode(node);
+
+               /* Although this may appear to be a busy loop, it is not.
+                  There are several conditions that cause E_REPEAT to be
+                  returned by the call to try_capture_block, all cases
+                  indicating some kind of state change that means you should
+                  retry the request and will get a different result.  In some
+                  cases this could be avoided with some extra code, but
+                  generally it is done because the necessary locks were
+                  released as a result of the operation and repeating is the
+                  simplest thing to do (less bug potential).  The cases are:
+                  atom fusion returns E_REPEAT after it completes (jnode and
+                  txnh were unlocked); race conditions in assign_block,
+                  assign_txnh, and init_fusion return E_REPEAT (trylock
+                  failure); after going to sleep in capture_fuse_wait
+                  (request was blocked but may now succeed).  I'm not quite
+                  sure how capture_copy works yet, but it may also return
+                  E_REPEAT.  When the request is legitimately blocked, the
+                  requestor goes to sleep in fuse_wait, so this is not a busy
+                  loop. */
+               /* NOTE-NIKITA: still don't understand:
+
+                  try_capture_block->capture_assign_txnh->spin_trylock_atom->E_REPEAT
+
+                  looks like busy loop?
+                */
+               goto repeat;
+       }
+
+       /* free extra atom object that was possibly allocated by
+          try_capture_block().
+
+          Do this before acquiring jnode spin lock to
+          minimize time spent under lock. --nikita */
+       if (atom_alloc != NULL) {
+               kmem_cache_free(_atom_slab, atom_alloc);
+       }
+
+       if (ret != 0) {
+               if (ret == -E_BLOCK) {
+                       assert("nikita-3360",
+                              cap_mode & TXN_CAPTURE_NONBLOCKING);
+                       ret = -E_REPEAT;
+               }
+
+               /* Failure means jnode is not locked.  FIXME_LATER_JMACD May
+                  want to fix the above code to avoid releasing the lock and
+                  re-acquiring it, but there are cases were failure occurs
+                  when the lock is not held, and those cases would need to be
+                  modified to re-take the lock. */
+               spin_lock_jnode(node);
+       }
+
+       /* Jnode is still locked. */
+       assert_spin_locked(&(node->guard));
+       return ret;
+}
+
+static void release_two_atoms(txn_atom *one, txn_atom *two)
+{
+       spin_unlock_atom(one);
+       atom_dec_and_unlock(two);
+       spin_lock_atom(one);
+       atom_dec_and_unlock(one);
+}
+
+/* This function sets up a call to try_capture_block and repeats as long as -E_REPEAT is
+   returned by that routine.  The txn_capture request mode is computed here depending on
+   the transaction handle's type and the lock request.  This is called from the depths of
+   the lock manager with the jnode lock held and it always returns with the jnode lock
+   held.
+*/
+
+/* fuse all 'active' atoms of lock owners of given node. */
+static void fuse_not_fused_lock_owners(txn_handle * txnh, znode * node)
+{
+       lock_handle *lh;
+       int repeat;
+       txn_atom *atomh, *atomf;
+       reiser4_context *me = get_current_context();
+       reiser4_context *ctx = NULL;
+
+       assert_spin_not_locked(&(ZJNODE(node)->guard));
+       assert_spin_not_locked(&(txnh->hlock));
+
+ repeat:
+       repeat = 0;
+       atomh = txnh_get_atom(txnh);
+       spin_unlock_txnh(txnh);
+       assert("zam-692", atomh != NULL);
+
+       spin_lock_zlock(&node->lock);
+       /* inspect list of lock owners */
+       list_for_each_entry(lh, &node->lock.owners, owners_link) {
+               ctx = get_context_by_lock_stack(lh->owner);
+               if (ctx == me)
+                       continue;
+               /* below we use two assumptions to avoid addition spin-locks
+                  for checking the condition :
+
+                  1) if the lock stack has lock, the transaction should be
+                  opened, i.e. ctx->trans != NULL;
+
+                  2) reading of well-aligned ctx->trans->atom is atomic, if it
+                  equals to the address of spin-locked atomh, we take that
+                  the atoms are the same, nothing has to be captured. */
+               if (atomh != ctx->trans->atom) {
+                       reiser4_wake_up(lh->owner);
+                       repeat = 1;
+                       break;
+               }
+       }
+       if (repeat) {
+               if (!spin_trylock_txnh(ctx->trans)) {
+                       spin_unlock_zlock(&node->lock);
+                       spin_unlock_atom(atomh);
+                       goto repeat;
+               }
+               atomf = ctx->trans->atom;
+               if (atomf == NULL) {
+                       capture_assign_txnh_nolock(atomh, ctx->trans);
+                       /* release zlock lock _after_ assigning the atom to the
+                        * transaction handle, otherwise the lock owner thread
+                        * may unlock all znodes, exit kernel context and here
+                        * we would access an invalid transaction handle. */
+                       spin_unlock_zlock(&node->lock);
+                       spin_unlock_atom(atomh);
+                       spin_unlock_txnh(ctx->trans);
+                       goto repeat;
+               }
+               assert("zam-1059", atomf != atomh);
+               spin_unlock_zlock(&node->lock);
+               atomic_inc(&atomh->refcount);
+               atomic_inc(&atomf->refcount);
+               spin_unlock_txnh(ctx->trans);
+               if (atomf > atomh) {
+                       spin_lock_atom_nested(atomf);
+               } else {
+                       spin_unlock_atom(atomh);
+                       spin_lock_atom(atomf);
+                       spin_lock_atom_nested(atomh);
+               }
+               if (atomh == atomf || !atom_isopen(atomh) || !atom_isopen(atomf)) {
+                       release_two_atoms(atomf, atomh);
+                       goto repeat;
+               }
+               atomic_dec(&atomh->refcount);
+               atomic_dec(&atomf->refcount);
+               capture_fuse_into(atomf, atomh);
+               goto repeat;
+       }
+       spin_unlock_zlock(&node->lock);
+       spin_unlock_atom(atomh);
+}
+
+/* This is the interface to capture unformatted nodes via their struct page
+   reference. Currently it is only used in reiser4_invalidatepage */
+int try_capture_page_to_invalidate(struct page *pg)
+{
+       int ret;
+       jnode *node;
+
+       assert("umka-292", pg != NULL);
+       assert("nikita-2597", PageLocked(pg));
+
+       if (IS_ERR(node = jnode_of_page(pg))) {
+               return PTR_ERR(node);
+       }
+
+       spin_lock_jnode(node);
+       unlock_page(pg);
+
+       ret = reiser4_try_capture(node, ZNODE_WRITE_LOCK, 0);
+       spin_unlock_jnode(node);
+       jput(node);
+       lock_page(pg);
+       return ret;
+}
+
+/* This informs the transaction manager when a node is deleted.  Add the block to the
+   atom's delete set and uncapture the block.
+
+VS-FIXME-HANS: this E_REPEAT paradigm clutters the code and creates a need for
+explanations.  find all the functions that use it, and unless there is some very
+good reason to use it (I have not noticed one so far and I doubt it exists, but maybe somewhere somehow....),
+move the loop to inside the function.
+
+VS-FIXME-HANS: can this code be at all streamlined?  In particular, can you lock and unlock the jnode fewer times?
+  */
+void reiser4_uncapture_page(struct page *pg)
+{
+       jnode *node;
+       txn_atom *atom;
+
+       assert("umka-199", pg != NULL);
+       assert("nikita-3155", PageLocked(pg));
+
+       clear_page_dirty_for_io(pg);
+
+       reiser4_wait_page_writeback(pg);
+
+       node = jprivate(pg);
+       BUG_ON(node == NULL);
+
+       spin_lock_jnode(node);
+
+       atom = jnode_get_atom(node);
+       if (atom == NULL) {
+               assert("jmacd-7111", !JF_ISSET(node, JNODE_DIRTY));
+               spin_unlock_jnode(node);
+               return;
+       }
+
+       /* We can remove jnode from transaction even if it is on flush queue
+        * prepped list, we only need to be sure that flush queue is not being
+        * written by reiser4_write_fq().  reiser4_write_fq() does not use atom
+        * spin lock for protection of the prepped nodes list, instead
+        * write_fq() increments atom's nr_running_queues counters for the time
+        * when prepped list is not protected by spin lock.  Here we check this
+        * counter if we want to remove jnode from flush queue and, if the
+        * counter is not zero, wait all reiser4_write_fq() for this atom to
+        * complete. This is not significant overhead. */
+       while (JF_ISSET(node, JNODE_FLUSH_QUEUED) && atom->nr_running_queues) {
+               spin_unlock_jnode(node);
+               /*
+                * at this moment we want to wait for "atom event", viz. wait
+                * until @node can be removed from flush queue. But
+                * reiser4_atom_wait_event() cannot be called with page locked,
+                * because it deadlocks with jnode_extent_write(). Unlock page,
+                * after making sure (through page_cache_get()) that it cannot
+                * be released from memory.
+                */
+               page_cache_get(pg);
+               unlock_page(pg);
+               reiser4_atom_wait_event(atom);
+               lock_page(pg);
+               /*
+                * page may has been detached by ->writepage()->releasepage().
+                */
+               reiser4_wait_page_writeback(pg);
+               spin_lock_jnode(node);
+               page_cache_release(pg);
+               atom = jnode_get_atom(node);
+/* VS-FIXME-HANS: improve the commenting in this function */
+               if (atom == NULL) {
+                       spin_unlock_jnode(node);
+                       return;
+               }
+       }
+       reiser4_uncapture_block(node);
+       spin_unlock_atom(atom);
+       jput(node);
+}
+
+/* this is used in extent's kill hook to uncapture and unhash jnodes attached to
+ * inode's tree of jnodes */
+void reiser4_uncapture_jnode(jnode * node)
+{
+       txn_atom *atom;
+
+       assert_spin_locked(&(node->guard));
+       assert("", node->pg == 0);
+
+       atom = jnode_get_atom(node);
+       if (atom == NULL) {
+               assert("jmacd-7111", !JF_ISSET(node, JNODE_DIRTY));
+               spin_unlock_jnode(node);
+               return;
+       }
+
+       reiser4_uncapture_block(node);
+       spin_unlock_atom(atom);
+       jput(node);
+}
+
+/* No-locking version of assign_txnh.  Sets the transaction handle's atom pointer,
+   increases atom refcount and txnh_count, adds to txnh_list. */
+static void capture_assign_txnh_nolock(txn_atom *atom, txn_handle *txnh)
+{
+       assert("umka-200", atom != NULL);
+       assert("umka-201", txnh != NULL);
+
+       assert_spin_locked(&(txnh->hlock));
+       assert_spin_locked(&(atom->alock));
+       assert("jmacd-824", txnh->atom == NULL);
+       assert("nikita-3540", atom_isopen(atom));
+       BUG_ON(txnh->atom != NULL);
+
+       atomic_inc(&atom->refcount);
+       txnh->atom = atom;
+       reiser4_ctx_gfp_mask_set();
+       list_add_tail(&txnh->txnh_link, &atom->txnh_list);
+       atom->txnh_count += 1;
+}
+
+/* No-locking version of assign_block.  Sets the block's atom pointer, references the
+   block, adds it to the clean or dirty capture_jnode list, increments capture_count. */
+static void capture_assign_block_nolock(txn_atom *atom, jnode *node)
+{
+       assert("umka-202", atom != NULL);
+       assert("umka-203", node != NULL);
+       assert_spin_locked(&(node->guard));
+       assert_spin_locked(&(atom->alock));
+       assert("jmacd-323", node->atom == NULL);
+       BUG_ON(!list_empty_careful(&node->capture_link));
+       assert("nikita-3470", !JF_ISSET(node, JNODE_DIRTY));
+
+       /* Pointer from jnode to atom is not counted in atom->refcount. */
+       node->atom = atom;
+
+       list_add_tail(&node->capture_link, ATOM_CLEAN_LIST(atom));
+       atom->capture_count += 1;
+       /* reference to jnode is acquired by atom. */
+       jref(node);
+
+       ON_DEBUG(count_jnode(atom, node, NOT_CAPTURED, CLEAN_LIST, 1));
+
+       LOCK_CNT_INC(t_refs);
+}
+
+/* common code for dirtying both unformatted jnodes and formatted znodes. */
+static void do_jnode_make_dirty(jnode * node, txn_atom * atom)
+{
+       assert_spin_locked(&(node->guard));
+       assert_spin_locked(&(atom->alock));
+       assert("jmacd-3981", !JF_ISSET(node, JNODE_DIRTY));
+
+       JF_SET(node, JNODE_DIRTY);
+
+       get_current_context()->nr_marked_dirty++;
+
+       /* We grab2flush_reserve one additional block only if node was
+          not CREATED and jnode_flush did not sort it into neither
+          relocate set nor overwrite one. If node is in overwrite or
+          relocate set we assume that atom's flush reserved counter was
+          already adjusted. */
+       if (!JF_ISSET(node, JNODE_CREATED) && !JF_ISSET(node, JNODE_RELOC)
+           && !JF_ISSET(node, JNODE_OVRWR) && jnode_is_leaf(node)
+           && !jnode_is_cluster_page(node)) {
+               assert("vs-1093", !reiser4_blocknr_is_fake(&node->blocknr));
+               assert("vs-1506", *jnode_get_block(node) != 0);
+               grabbed2flush_reserved_nolock(atom, (__u64) 1);
+               JF_SET(node, JNODE_FLUSH_RESERVED);
+       }
+
+       if (!JF_ISSET(node, JNODE_FLUSH_QUEUED)) {
+               /* If the atom is not set yet, it will be added to the appropriate list in
+                  capture_assign_block_nolock. */
+               /* Sometimes a node is set dirty before being captured -- the case for new
+                  jnodes.  In that case the jnode will be added to the appropriate list
+                  in capture_assign_block_nolock. Another reason not to re-link jnode is
+                  that jnode is on a flush queue (see flush.c for details) */
+
+               int level = jnode_get_level(node);
+
+               assert("nikita-3152", !JF_ISSET(node, JNODE_OVRWR));
+               assert("zam-654", atom->stage < ASTAGE_PRE_COMMIT);
+               assert("nikita-2607", 0 <= level);
+               assert("nikita-2606", level <= REAL_MAX_ZTREE_HEIGHT);
+
+               /* move node to atom's dirty list */
+               list_move_tail(&node->capture_link, ATOM_DIRTY_LIST(atom, level));
+               ON_DEBUG(count_jnode
+                        (atom, node, NODE_LIST(node), DIRTY_LIST, 1));
+       }
+}
+
+/* Set the dirty status for this (spin locked) jnode. */
+void jnode_make_dirty_locked(jnode * node)
+{
+       assert("umka-204", node != NULL);
+       assert_spin_locked(&(node->guard));
+
+       if (REISER4_DEBUG && rofs_jnode(node)) {
+               warning("nikita-3365", "Dirtying jnode on rofs");
+               dump_stack();
+       }
+
+       /* Fast check for already dirty node */
+       if (!JF_ISSET(node, JNODE_DIRTY)) {
+               txn_atom *atom;
+
+               atom = jnode_get_atom(node);
+               assert("vs-1094", atom);
+               /* Check jnode dirty status again because node spin lock might
+                * be released inside jnode_get_atom(). */
+               if (likely(!JF_ISSET(node, JNODE_DIRTY)))
+                       do_jnode_make_dirty(node, atom);
+               spin_unlock_atom(atom);
+       }
+}
+
+/* Set the dirty status for this znode. */
+void znode_make_dirty(znode * z)
+{
+       jnode *node;
+       struct page *page;
+
+       assert("umka-204", z != NULL);
+       assert("nikita-3290", znode_above_root(z) || znode_is_loaded(z));
+       assert("nikita-3560", znode_is_write_locked(z));
+
+       node = ZJNODE(z);
+       /* znode is longterm locked, we can check dirty bit without spinlock */
+       if (JF_ISSET(node, JNODE_DIRTY)) {
+               /* znode is dirty already. All we have to do is to change znode version */
+               z->version = znode_build_version(jnode_get_tree(node));
+               return;
+       }
+
+       spin_lock_jnode(node);
+       jnode_make_dirty_locked(node);
+       page = jnode_page(node);
+       if (page != NULL) {
+               /* this is useful assertion (allows one to check that no
+                * modifications are lost due to update of in-flight page),
+                * but it requires locking on page to check PG_writeback
+                * bit. */
+               /* assert("nikita-3292",
+                  !PageWriteback(page) || ZF_ISSET(z, JNODE_WRITEBACK)); */
+               page_cache_get(page);
+
+               /* jnode lock is not needed for the rest of
+                * znode_set_dirty(). */
+               spin_unlock_jnode(node);
+               /* reiser4 file write code calls set_page_dirty for
+                * unformatted nodes, for formatted nodes we do it here. */
+               reiser4_set_page_dirty_internal(page);
+               page_cache_release(page);
+               /* bump version counter in znode */
+               z->version = znode_build_version(jnode_get_tree(node));
+       } else {
+               assert("zam-596", znode_above_root(JZNODE(node)));
+               spin_unlock_jnode(node);
+       }
+
+       assert("nikita-1900", znode_is_write_locked(z));
+       assert("jmacd-9777", node->atom != NULL);
+}
+
+int reiser4_sync_atom(txn_atom * atom)
+{
+       int result;
+       txn_handle *txnh;
+
+       txnh = get_current_context()->trans;
+
+       result = 0;
+       if (atom != NULL) {
+               if (atom->stage < ASTAGE_PRE_COMMIT) {
+                       spin_lock_txnh(txnh);
+                       capture_assign_txnh_nolock(atom, txnh);
+                       result = force_commit_atom(txnh);
+               } else if (atom->stage < ASTAGE_POST_COMMIT) {
+                       /* wait atom commit */
+                       reiser4_atom_wait_event(atom);
+                       /* try once more */
+                       result = RETERR(-E_REPEAT);
+               } else
+                       spin_unlock_atom(atom);
+       }
+       return result;
+}
+
+#if REISER4_DEBUG
+
+/* move jnode form one list to another
+   call this after atom->capture_count is updated */
+void
+count_jnode(txn_atom * atom, jnode * node, atom_list old_list,
+           atom_list new_list, int check_lists)
+{
+       struct list_head *pos;
+
+       assert("zam-1018", atom_is_protected(atom));
+       assert_spin_locked(&(node->guard));
+       assert("", NODE_LIST(node) == old_list);
+
+       switch (NODE_LIST(node)) {
+       case NOT_CAPTURED:
+               break;
+       case DIRTY_LIST:
+               assert("", atom->dirty > 0);
+               atom->dirty--;
+               break;
+       case CLEAN_LIST:
+               assert("", atom->clean > 0);
+               atom->clean--;
+               break;
+       case FQ_LIST:
+               assert("", atom->fq > 0);
+               atom->fq--;
+               break;
+       case WB_LIST:
+               assert("", atom->wb > 0);
+               atom->wb--;
+               break;
+       case OVRWR_LIST:
+               assert("", atom->ovrwr > 0);
+               atom->ovrwr--;
+               break;
+       default:
+               impossible("", "");
+       }
+
+       switch (new_list) {
+       case NOT_CAPTURED:
+               break;
+       case DIRTY_LIST:
+               atom->dirty++;
+               break;
+       case CLEAN_LIST:
+               atom->clean++;
+               break;
+       case FQ_LIST:
+               atom->fq++;
+               break;
+       case WB_LIST:
+               atom->wb++;
+               break;
+       case OVRWR_LIST:
+               atom->ovrwr++;
+               break;
+       default:
+               impossible("", "");
+       }
+       ASSIGN_NODE_LIST(node, new_list);
+       if (0 && check_lists) {
+               int count;
+               tree_level level;
+
+               count = 0;
+
+               /* flush queue list */
+               /* reiser4_check_fq(atom); */
+
+               /* dirty list */
+               count = 0;
+               for (level = 0; level < REAL_MAX_ZTREE_HEIGHT + 1; level += 1) {
+                       list_for_each(pos, ATOM_DIRTY_LIST(atom, level))
+                               count++;
+               }
+               if (count != atom->dirty)
+                       warning("", "dirty counter %d, real %d\n", atom->dirty,
+                               count);
+
+               /* clean list */
+               count = 0;
+               list_for_each(pos, ATOM_CLEAN_LIST(atom))
+                       count++;
+               if (count != atom->clean)
+                       warning("", "clean counter %d, real %d\n", atom->clean,
+                               count);
+
+               /* wb list */
+               count = 0;
+               list_for_each(pos, ATOM_WB_LIST(atom))
+                       count++;
+               if (count != atom->wb)
+                       warning("", "wb counter %d, real %d\n", atom->wb,
+                               count);
+
+               /* overwrite list */
+               count = 0;
+               list_for_each(pos, ATOM_OVRWR_LIST(atom))
+                       count++;
+
+               if (count != atom->ovrwr)
+                       warning("", "ovrwr counter %d, real %d\n", atom->ovrwr,
+                               count);
+       }
+       assert("vs-1624", atom->num_queued == atom->fq);
+       if (atom->capture_count !=
+           atom->dirty + atom->clean + atom->ovrwr + atom->wb + atom->fq) {
+               printk
+                   ("count %d, dirty %d clean %d ovrwr %d wb %d fq %d\n",
+                    atom->capture_count, atom->dirty, atom->clean, atom->ovrwr,
+                    atom->wb, atom->fq);
+               assert("vs-1622",
+                      atom->capture_count ==
+                      atom->dirty + atom->clean + atom->ovrwr + atom->wb +
+                      atom->fq);
+       }
+}
+
+#endif
+
+/* Make node OVRWR and put it on atom->overwrite_nodes list, atom lock and jnode
+ * lock should be taken before calling this function. */
+void jnode_make_wander_nolock(jnode * node)
+{
+       txn_atom *atom;
+
+       assert("nikita-2431", node != NULL);
+       assert("nikita-2432", !JF_ISSET(node, JNODE_RELOC));
+       assert("nikita-3153", JF_ISSET(node, JNODE_DIRTY));
+       assert("zam-897", !JF_ISSET(node, JNODE_FLUSH_QUEUED));
+       assert("nikita-3367", !reiser4_blocknr_is_fake(jnode_get_block(node)));
+
+       atom = node->atom;
+
+       assert("zam-895", atom != NULL);
+       assert("zam-894", atom_is_protected(atom));
+
+       JF_SET(node, JNODE_OVRWR);
+       /* move node to atom's overwrite list */
+       list_move_tail(&node->capture_link, ATOM_OVRWR_LIST(atom));
+       ON_DEBUG(count_jnode(atom, node, DIRTY_LIST, OVRWR_LIST, 1));
+}
+
+/* Same as jnode_make_wander_nolock, but all necessary locks are taken inside
+ * this function. */
+void jnode_make_wander(jnode * node)
+{
+       txn_atom *atom;
+
+       spin_lock_jnode(node);
+       atom = jnode_get_atom(node);
+       assert("zam-913", atom != NULL);
+       assert("zam-914", !JF_ISSET(node, JNODE_RELOC));
+
+       jnode_make_wander_nolock(node);
+       spin_unlock_atom(atom);
+       spin_unlock_jnode(node);
+}
+
+/* this just sets RELOC bit  */
+static void jnode_make_reloc_nolock(flush_queue_t * fq, jnode * node)
+{
+       assert_spin_locked(&(node->guard));
+       assert("zam-916", JF_ISSET(node, JNODE_DIRTY));
+       assert("zam-917", !JF_ISSET(node, JNODE_RELOC));
+       assert("zam-918", !JF_ISSET(node, JNODE_OVRWR));
+       assert("zam-920", !JF_ISSET(node, JNODE_FLUSH_QUEUED));
+       assert("nikita-3367", !reiser4_blocknr_is_fake(jnode_get_block(node)));
+       jnode_set_reloc(node);
+}
+
+/* Make znode RELOC and put it on flush queue */
+void znode_make_reloc(znode * z, flush_queue_t * fq)
+{
+       jnode *node;
+       txn_atom *atom;
+
+       node = ZJNODE(z);
+       spin_lock_jnode(node);
+
+       atom = jnode_get_atom(node);
+       assert("zam-919", atom != NULL);
+
+       jnode_make_reloc_nolock(fq, node);
+       queue_jnode(fq, node);
+
+       spin_unlock_atom(atom);
+       spin_unlock_jnode(node);
+
+}
+
+/* Make unformatted node RELOC and put it on flush queue */
+void unformatted_make_reloc(jnode *node, flush_queue_t *fq)
+{
+       assert("vs-1479", jnode_is_unformatted(node));
+
+       jnode_make_reloc_nolock(fq, node);
+       queue_jnode(fq, node);
+}
+
+int reiser4_capture_super_block(struct super_block *s)
+{
+       int result;
+       znode *uber;
+       lock_handle lh;
+
+       init_lh(&lh);
+       result = get_uber_znode(reiser4_get_tree(s),
+                               ZNODE_WRITE_LOCK, ZNODE_LOCK_LOPRI, &lh);
+       if (result)
+               return result;
+
+       uber = lh.node;
+       /* Grabbing one block for superblock */
+       result = reiser4_grab_space_force((__u64) 1, BA_RESERVED);
+       if (result != 0)
+               return result;
+
+       znode_make_dirty(uber);
+
+       done_lh(&lh);
+       return 0;
+}
+
+/* Wakeup every handle on the atom's WAITFOR list */
+static void wakeup_atom_waitfor_list(txn_atom * atom)
+{
+       txn_wait_links *wlinks;
+
+       assert("umka-210", atom != NULL);
+
+       /* atom is locked */
+       list_for_each_entry(wlinks, &atom->fwaitfor_list, _fwaitfor_link) {
+               if (wlinks->waitfor_cb == NULL ||
+                   wlinks->waitfor_cb(atom, wlinks))
+                       /* Wake up. */
+                       reiser4_wake_up(wlinks->_lock_stack);
+       }
+}
+
+/* Wakeup every handle on the atom's WAITING list */
+static void wakeup_atom_waiting_list(txn_atom * atom)
+{
+       txn_wait_links *wlinks;
+
+       assert("umka-211", atom != NULL);
+
+       /* atom is locked */
+       list_for_each_entry(wlinks, &atom->fwaiting_list, _fwaiting_link) {
+               if (wlinks->waiting_cb == NULL ||
+                   wlinks->waiting_cb(atom, wlinks))
+                       /* Wake up. */
+                       reiser4_wake_up(wlinks->_lock_stack);
+       }
+}
+
+/* helper function used by capture_fuse_wait() to avoid "spurious wake-ups" */
+static int wait_for_fusion(txn_atom * atom, txn_wait_links * wlinks)
+{
+       assert("nikita-3330", atom != NULL);
+       assert_spin_locked(&(atom->alock));
+
+       /* atom->txnh_count == 1 is for waking waiters up if we are releasing
+        * last transaction handle. */
+       return atom->stage != ASTAGE_CAPTURE_WAIT || atom->txnh_count == 1;
+}
+
+/* The general purpose of this function is to wait on the first of two possible events.
+   The situation is that a handle (and its atom atomh) is blocked trying to capture a
+   block (i.e., node) but the node's atom (atomf) is in the CAPTURE_WAIT state.  The
+   handle's atom (atomh) is not in the CAPTURE_WAIT state.  However, atomh could fuse with
+   another atom or, due to age, enter the CAPTURE_WAIT state itself, at which point it
+   needs to unblock the handle to avoid deadlock.  When the txnh is unblocked it will
+   proceed and fuse the two atoms in the CAPTURE_WAIT state.
+
+   In other words, if either atomh or atomf change state, the handle will be awakened,
+   thus there are two lists per atom: WAITING and WAITFOR.
+
+   This is also called by capture_assign_txnh with (atomh == NULL) to wait for atomf to
+   close but it is not assigned to an atom of its own.
+
+   Lock ordering in this method: all four locks are held: JNODE_LOCK, TXNH_LOCK,
+   BOTH_ATOM_LOCKS.  Result: all four locks are released.
+*/
+static int capture_fuse_wait(txn_handle * txnh, txn_atom * atomf,
+                   txn_atom * atomh, txn_capture mode)
+{
+       int ret;
+       txn_wait_links wlinks;
+
+       assert("umka-213", txnh != NULL);
+       assert("umka-214", atomf != NULL);
+
+       if ((mode & TXN_CAPTURE_NONBLOCKING) != 0) {
+               spin_unlock_txnh(txnh);
+               spin_unlock_atom(atomf);
+
+               if (atomh) {
+                       spin_unlock_atom(atomh);
+               }
+
+               return RETERR(-E_BLOCK);
+       }
+
+       /* Initialize the waiting list links. */
+       init_wlinks(&wlinks);
+
+       /* Add txnh to atomf's waitfor list, unlock atomf. */
+       list_add_tail(&wlinks._fwaitfor_link, &atomf->fwaitfor_list);
+       wlinks.waitfor_cb = wait_for_fusion;
+       atomic_inc(&atomf->refcount);
+       spin_unlock_atom(atomf);
+
+       if (atomh) {
+               /* Add txnh to atomh's waiting list, unlock atomh. */
+               list_add_tail(&wlinks._fwaiting_link, &atomh->fwaiting_list);
+               atomic_inc(&atomh->refcount);
+               spin_unlock_atom(atomh);
+       }
+
+       /* Go to sleep. */
+       spin_unlock_txnh(txnh);
+
+       ret = reiser4_prepare_to_sleep(wlinks._lock_stack);
+       if (ret == 0) {
+               reiser4_go_to_sleep(wlinks._lock_stack);
+               ret = RETERR(-E_REPEAT);
+       }
+
+       /* Remove from the waitfor list. */
+       spin_lock_atom(atomf);
+
+       list_del(&wlinks._fwaitfor_link);
+       atom_dec_and_unlock(atomf);
+
+       if (atomh) {
+               /* Remove from the waiting list. */
+               spin_lock_atom(atomh);
+               list_del(&wlinks._fwaiting_link);
+               atom_dec_and_unlock(atomh);
+       }
+       return ret;
+}
+
+static void lock_two_atoms(txn_atom * one, txn_atom * two)
+{
+       assert("zam-1067", one != two);
+
+       /* lock the atom with lesser address first */
+       if (one < two) {
+               spin_lock_atom(one);
+               spin_lock_atom_nested(two);
+       } else {
+               spin_lock_atom(two);
+               spin_lock_atom_nested(one);
+       }
+}
+
+/* Perform the necessary work to prepare for fusing two atoms, which involves
+ * acquiring two atom locks in the proper order.  If one of the node's atom is
+ * blocking fusion (i.e., it is in the CAPTURE_WAIT stage) and the handle's
+ * atom is not then the handle's request is put to sleep.  If the node's atom
+ * is committing, then the node can be copy-on-captured.  Otherwise, pick the
+ * atom with fewer pointers to be fused into the atom with more pointer and
+ * call capture_fuse_into.
+ */
+static int capture_init_fusion(jnode *node, txn_handle *txnh, txn_capture mode)
+{
+       txn_atom * txnh_atom = txnh->atom;
+       txn_atom * block_atom = node->atom;
+
+       atomic_inc(&txnh_atom->refcount);
+       atomic_inc(&block_atom->refcount);
+
+       spin_unlock_txnh(txnh);
+       spin_unlock_jnode(node);
+
+       lock_two_atoms(txnh_atom, block_atom);
+
+       if (txnh->atom != txnh_atom || node->atom != block_atom ) {
+               release_two_atoms(txnh_atom, block_atom);
+               return RETERR(-E_REPEAT);
+       }
+
+       atomic_dec(&txnh_atom->refcount);
+       atomic_dec(&block_atom->refcount);
+
+       assert ("zam-1066", atom_isopen(txnh_atom));
+
+       if (txnh_atom->stage >= block_atom->stage ||
+           (block_atom->stage == ASTAGE_CAPTURE_WAIT && block_atom->txnh_count == 0)) {
+               capture_fuse_into(txnh_atom, block_atom);
+               return RETERR(-E_REPEAT);
+       }
+       spin_lock_txnh(txnh);
+       return capture_fuse_wait(txnh, block_atom, txnh_atom, mode);
+}
+
+/* This function splices together two jnode lists (small and large) and sets all jnodes in
+   the small list to point to the large atom.  Returns the length of the list. */
+static int
+capture_fuse_jnode_lists(txn_atom *large, struct list_head *large_head,
+                        struct list_head *small_head)
+{
+       int count = 0;
+       jnode *node;
+
+       assert("umka-218", large != NULL);
+       assert("umka-219", large_head != NULL);
+       assert("umka-220", small_head != NULL);
+       /* small atom should be locked also. */
+       assert_spin_locked(&(large->alock));
+
+       /* For every jnode on small's capture list... */
+       list_for_each_entry(node, small_head, capture_link) {
+               count += 1;
+
+               /* With the jnode lock held, update atom pointer. */
+               spin_lock_jnode(node);
+               node->atom = large;
+               spin_unlock_jnode(node);
+       }
+
+       /* Splice the lists. */
+       list_splice_init(small_head, large_head->prev);
+
+       return count;
+}
+
+/* This function splices together two txnh lists (small and large) and sets all txn handles in
+   the small list to point to the large atom.  Returns the length of the list. */
+static int
+capture_fuse_txnh_lists(txn_atom *large, struct list_head *large_head,
+                       struct list_head *small_head)
+{
+       int count = 0;
+       txn_handle *txnh;
+
+       assert("umka-221", large != NULL);
+       assert("umka-222", large_head != NULL);
+       assert("umka-223", small_head != NULL);
+
+       /* Adjust every txnh to the new atom. */
+       list_for_each_entry(txnh, small_head, txnh_link) {
+               count += 1;
+
+               /* With the txnh lock held, update atom pointer. */
+               spin_lock_txnh(txnh);
+               txnh->atom = large;
+               spin_unlock_txnh(txnh);
+       }
+
+       /* Splice the txn_handle list. */
+       list_splice_init(small_head, large_head->prev);
+
+       return count;
+}
+
+/* This function fuses two atoms.  The captured nodes and handles belonging to SMALL are
+   added to LARGE and their ->atom pointers are all updated.  The associated counts are
+   updated as well, and any waiting handles belonging to either are awakened.  Finally the
+   smaller atom's refcount is decremented.
+*/
+static void capture_fuse_into(txn_atom * small, txn_atom * large)
+{
+       int level;
+       unsigned zcount = 0;
+       unsigned tcount = 0;
+
+       assert("umka-224", small != NULL);
+       assert("umka-225", small != NULL);
+
+       assert_spin_locked(&(large->alock));
+       assert_spin_locked(&(small->alock));
+
+       assert("jmacd-201", atom_isopen(small));
+       assert("jmacd-202", atom_isopen(large));
+
+       /* Splice and update the per-level dirty jnode lists */
+       for (level = 0; level < REAL_MAX_ZTREE_HEIGHT + 1; level += 1) {
+               zcount +=
+                   capture_fuse_jnode_lists(large,
+                                            ATOM_DIRTY_LIST(large, level),
+                                            ATOM_DIRTY_LIST(small, level));
+       }
+
+       /* Splice and update the [clean,dirty] jnode and txnh lists */
+       zcount +=
+           capture_fuse_jnode_lists(large, ATOM_CLEAN_LIST(large),
+                                    ATOM_CLEAN_LIST(small));
+       zcount +=
+           capture_fuse_jnode_lists(large, ATOM_OVRWR_LIST(large),
+                                    ATOM_OVRWR_LIST(small));
+       zcount +=
+           capture_fuse_jnode_lists(large, ATOM_WB_LIST(large),
+                                    ATOM_WB_LIST(small));
+       zcount +=
+           capture_fuse_jnode_lists(large, &large->inodes, &small->inodes);
+       tcount +=
+           capture_fuse_txnh_lists(large, &large->txnh_list,
+                                   &small->txnh_list);
+
+       /* Check our accounting. */
+       assert("jmacd-1063",
+              zcount + small->num_queued == small->capture_count);
+       assert("jmacd-1065", tcount == small->txnh_count);
+
+       /* sum numbers of waiters threads */
+       large->nr_waiters += small->nr_waiters;
+       small->nr_waiters = 0;
+
+       /* splice flush queues */
+       reiser4_fuse_fq(large, small);
+
+       /* update counter of jnode on every atom' list */
+       ON_DEBUG(large->dirty += small->dirty;
+                small->dirty = 0;
+                large->clean += small->clean;
+                small->clean = 0;
+                large->ovrwr += small->ovrwr;
+                small->ovrwr = 0;
+                large->wb += small->wb;
+                small->wb = 0;
+                large->fq += small->fq;
+                small->fq = 0;);
+
+       /* count flushers in result atom */
+       large->nr_flushers += small->nr_flushers;
+       small->nr_flushers = 0;
+
+       /* update counts of flushed nodes */
+       large->flushed += small->flushed;
+       small->flushed = 0;
+
+       /* Transfer list counts to large. */
+       large->txnh_count += small->txnh_count;
+       large->capture_count += small->capture_count;
+
+       /* Add all txnh references to large. */
+       atomic_add(small->txnh_count, &large->refcount);
+       atomic_sub(small->txnh_count, &small->refcount);
+
+       /* Reset small counts */
+       small->txnh_count = 0;
+       small->capture_count = 0;
+
+       /* Assign the oldest start_time, merge flags. */
+       large->start_time = min(large->start_time, small->start_time);
+       large->flags |= small->flags;
+
+       /* Merge blocknr sets. */
+       blocknr_set_merge(&small->delete_set, &large->delete_set);
+       blocknr_set_merge(&small->wandered_map, &large->wandered_map);
+
+       /* Merge allocated/deleted file counts */
+       large->nr_objects_deleted += small->nr_objects_deleted;
+       large->nr_objects_created += small->nr_objects_created;
+
+       small->nr_objects_deleted = 0;
+       small->nr_objects_created = 0;
+
+       /* Merge allocated blocks counts */
+       large->nr_blocks_allocated += small->nr_blocks_allocated;
+
+       large->nr_running_queues += small->nr_running_queues;
+       small->nr_running_queues = 0;
+
+       /* Merge blocks reserved for overwrite set. */
+       large->flush_reserved += small->flush_reserved;
+       small->flush_reserved = 0;
+
+       if (large->stage < small->stage) {
+               /* Large only needs to notify if it has changed state. */
+               reiser4_atom_set_stage(large, small->stage);
+               wakeup_atom_waiting_list(large);
+       }
+
+       reiser4_atom_set_stage(small, ASTAGE_INVALID);
+
+       /* Notify any waiters--small needs to unload its wait lists.  Waiters
+          actually remove themselves from the list before returning from the
+          fuse_wait function. */
+       wakeup_atom_waiting_list(small);
+
+       /* Unlock atoms */
+       spin_unlock_atom(large);
+       atom_dec_and_unlock(small);
+}
+
+/* TXNMGR STUFF */
+
+/* Release a block from the atom, reversing the effects of being captured,
+   do not release atom's reference to jnode due to holding spin-locks.
+   Currently this is only called when the atom commits.
+
+   NOTE: this function does not release a (journal) reference to jnode
+   due to locking optimizations, you should call jput() somewhere after
+   calling reiser4_uncapture_block(). */
+void reiser4_uncapture_block(jnode * node)
+{
+       txn_atom *atom;
+
+       assert("umka-226", node != NULL);
+       atom = node->atom;
+       assert("umka-228", atom != NULL);
+
+       assert("jmacd-1021", node->atom == atom);
+       assert_spin_locked(&(node->guard));
+       assert("jmacd-1023", atom_is_protected(atom));
+
+       JF_CLR(node, JNODE_DIRTY);
+       JF_CLR(node, JNODE_RELOC);
+       JF_CLR(node, JNODE_OVRWR);
+       JF_CLR(node, JNODE_CREATED);
+       JF_CLR(node, JNODE_WRITEBACK);
+       JF_CLR(node, JNODE_REPACK);
+
+       list_del_init(&node->capture_link);
+       if (JF_ISSET(node, JNODE_FLUSH_QUEUED)) {
+               assert("zam-925", atom_isopen(atom));
+               assert("vs-1623", NODE_LIST(node) == FQ_LIST);
+               ON_DEBUG(atom->num_queued--);
+               JF_CLR(node, JNODE_FLUSH_QUEUED);
+       }
+       atom->capture_count -= 1;
+       ON_DEBUG(count_jnode(atom, node, NODE_LIST(node), NOT_CAPTURED, 1));
+       node->atom = NULL;
+
+       spin_unlock_jnode(node);
+       LOCK_CNT_DEC(t_refs);
+}
+
+/* Unconditional insert of jnode into atom's overwrite list. Currently used in
+   bitmap-based allocator code for adding modified bitmap blocks the
+   transaction. @atom and @node are spin locked */
+void insert_into_atom_ovrwr_list(txn_atom * atom, jnode * node)
+{
+       assert("zam-538", atom_is_protected(atom));
+       assert_spin_locked(&(node->guard));
+       assert("zam-899", JF_ISSET(node, JNODE_OVRWR));
+       assert("zam-543", node->atom == NULL);
+       assert("vs-1433", !jnode_is_unformatted(node) && !jnode_is_znode(node));
+
+       list_add(&node->capture_link, ATOM_OVRWR_LIST(atom));
+       jref(node);
+       node->atom = atom;
+       atom->capture_count++;
+       ON_DEBUG(count_jnode(atom, node, NODE_LIST(node), OVRWR_LIST, 1));
+}
+
+static int count_deleted_blocks_actor(txn_atom * atom,
+                                     const reiser4_block_nr * a,
+                                     const reiser4_block_nr * b, void *data)
+{
+       reiser4_block_nr *counter = data;
+
+       assert("zam-995", data != NULL);
+       assert("zam-996", a != NULL);
+       if (b == NULL)
+               *counter += 1;
+       else
+               *counter += *b;
+       return 0;
+}
+
+reiser4_block_nr txnmgr_count_deleted_blocks(void)
+{
+       reiser4_block_nr result;
+       txn_mgr *tmgr = &get_super_private(reiser4_get_current_sb())->tmgr;
+       txn_atom *atom;
+
+       result = 0;
+
+       spin_lock_txnmgr(tmgr);
+       list_for_each_entry(atom, &tmgr->atoms_list, atom_link) {
+               spin_lock_atom(atom);
+               if (atom_isopen(atom))
+                       blocknr_set_iterator(
+                               atom, &atom->delete_set,
+                               count_deleted_blocks_actor, &result, 0);
+               spin_unlock_atom(atom);
+       }
+       spin_unlock_txnmgr(tmgr);
+
+       return result;
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: "K&R"
+ * mode-name: "LC"
+ * c-basic-offset: 8
+ * tab-width: 8
+ * fill-column: 79
+ * End:
+ */
diff -urN linux-2.6.20.orig/fs/reiser4/txnmgr.h linux-2.6.20/fs/reiser4/txnmgr.h
--- linux-2.6.20.orig/fs/reiser4/txnmgr.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/txnmgr.h    2007-05-06 14:50:43.899038216 +0400
@@ -0,0 +1,708 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* data-types and function declarations for transaction manager. See txnmgr.c
+ * for details. */
+
+#ifndef __REISER4_TXNMGR_H__
+#define __REISER4_TXNMGR_H__
+
+#include "forward.h"
+#include "dformat.h"
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <asm/atomic.h>
+#include <linux/wait.h>
+
+/* TYPE DECLARATIONS */
+
+/* This enumeration describes the possible types of a capture request (reiser4_try_capture).
+   A capture request dynamically assigns a block to the calling thread's transaction
+   handle. */
+typedef enum {
+       /* A READ_ATOMIC request indicates that a block will be read and that the caller's
+          atom should fuse in order to ensure that the block commits atomically with the
+          caller. */
+       TXN_CAPTURE_READ_ATOMIC = (1 << 0),
+
+       /* A READ_NONCOM request indicates that a block will be read and that the caller is
+          willing to read a non-committed block without causing atoms to fuse. */
+       TXN_CAPTURE_READ_NONCOM = (1 << 1),
+
+       /* A READ_MODIFY request indicates that a block will be read but that the caller
+          wishes for the block to be captured as it will be written.  This capture request
+          mode is not currently used, but eventually it will be useful for preventing
+          deadlock in read-modify-write cycles. */
+       TXN_CAPTURE_READ_MODIFY = (1 << 2),
+
+       /* A WRITE capture request indicates that a block will be modified and that atoms
+          should fuse to make the commit atomic. */
+       TXN_CAPTURE_WRITE = (1 << 3),
+
+       /* CAPTURE_TYPES is a mask of the four above capture types, used to separate the
+          exclusive type designation from extra bits that may be supplied -- see
+          below. */
+       TXN_CAPTURE_TYPES = (TXN_CAPTURE_READ_ATOMIC |
+                            TXN_CAPTURE_READ_NONCOM | TXN_CAPTURE_READ_MODIFY |
+                            TXN_CAPTURE_WRITE),
+
+       /* A subset of CAPTURE_TYPES, CAPTURE_WTYPES is a mask of request types that
+          indicate modification will occur. */
+       TXN_CAPTURE_WTYPES = (TXN_CAPTURE_READ_MODIFY | TXN_CAPTURE_WRITE),
+
+       /* An option to reiser4_try_capture, NONBLOCKING indicates that the caller would
+          prefer not to sleep waiting for an aging atom to commit. */
+       TXN_CAPTURE_NONBLOCKING = (1 << 4),
+
+       /* An option to reiser4_try_capture to prevent atom fusion, just simple
+          capturing is allowed */
+       TXN_CAPTURE_DONT_FUSE = (1 << 5)
+
+       /* This macro selects only the exclusive capture request types, stripping out any
+          options that were supplied (i.e., NONBLOCKING). */
+#define CAPTURE_TYPE(x) ((x) & TXN_CAPTURE_TYPES)
+} txn_capture;
+
+/* There are two kinds of transaction handle: WRITE_FUSING and READ_FUSING, the only
+   difference is in the handling of read requests.  A WRITE_FUSING transaction handle
+   defaults read capture requests to TXN_CAPTURE_READ_NONCOM whereas a READ_FUSIONG
+   transaction handle defaults to TXN_CAPTURE_READ_ATOMIC. */
+typedef enum {
+       TXN_WRITE_FUSING = (1 << 0),
+       TXN_READ_FUSING = (1 << 1) | TXN_WRITE_FUSING,  /* READ implies WRITE */
+} txn_mode;
+
+/* Every atom has a stage, which is one of these exclusive values: */
+typedef enum {
+       /* Initially an atom is free. */
+       ASTAGE_FREE = 0,
+
+       /* An atom begins by entering the CAPTURE_FUSE stage, where it proceeds to capture
+          blocks and fuse with other atoms. */
+       ASTAGE_CAPTURE_FUSE = 1,
+
+       /* We need to have a ASTAGE_CAPTURE_SLOW in which an atom fuses with one node for every X nodes it flushes to disk where X > 1. */
+
+       /* When an atom reaches a certain age it must do all it can to commit.  An atom in
+          the CAPTURE_WAIT stage refuses new transaction handles and prevents fusion from
+          atoms in the CAPTURE_FUSE stage. */
+       ASTAGE_CAPTURE_WAIT = 2,
+
+       /* Waiting for I/O before commit.  Copy-on-capture (see
+          http://namesys.com/v4/v4.html). */
+       ASTAGE_PRE_COMMIT = 3,
+
+       /* Post-commit overwrite I/O.  Steal-on-capture. */
+       ASTAGE_POST_COMMIT = 4,
+
+       /* Atom which waits for the removal of the last reference to (it? ) to
+        * be deleted from memory  */
+       ASTAGE_DONE = 5,
+
+       /* invalid atom. */
+       ASTAGE_INVALID = 6,
+
+} txn_stage;
+
+/* Certain flags may be set in the txn_atom->flags field. */
+typedef enum {
+       /* Indicates that the atom should commit as soon as possible. */
+       ATOM_FORCE_COMMIT = (1 << 0),
+       /* to avoid endless loop, mark the atom (which was considered as too
+        * small) after failed attempt to fuse it. */
+       ATOM_CANCEL_FUSION = (1 << 1)
+} txn_flags;
+
+/* Flags for controlling commit_txnh */
+typedef enum {
+       /* Wait commit atom completion in commit_txnh */
+       TXNH_WAIT_COMMIT = 0x2,
+       /* Don't commit atom when this handle is closed */
+       TXNH_DONT_COMMIT = 0x4
+} txn_handle_flags_t;
+
+/* TYPE DEFINITIONS */
+
+/* A note on lock ordering: the handle & jnode spinlock protects reading of their ->atom
+   fields, so typically an operation on the atom through either of these objects must (1)
+   lock the object, (2) read the atom pointer, (3) lock the atom.
+
+   During atom fusion, the process holds locks on both atoms at once.  Then, it iterates
+   through the list of handles and pages held by the smaller of the two atoms.  For each
+   handle and page referencing the smaller atom, the fusing process must: (1) lock the
+   object, and (2) update the atom pointer.
+
+   You can see that there is a conflict of lock ordering here, so the more-complex
+   procedure should have priority, i.e., the fusing process has priority so that it is
+   guaranteed to make progress and to avoid restarts.
+
+   This decision, however, means additional complexity for aquiring the atom lock in the
+   first place.
+
+   The general original procedure followed in the code was:
+
+       TXN_OBJECT *obj = ...;
+       TXN_ATOM   *atom;
+
+       spin_lock (& obj->_lock);
+
+       atom = obj->_atom;
+
+       if (! spin_trylock_atom (atom))
+         {
+           spin_unlock (& obj->_lock);
+           RESTART OPERATION, THERE WAS A RACE;
+         }
+
+       ELSE YOU HAVE BOTH ATOM AND OBJ LOCKED
+
+   It has however been found that this wastes CPU a lot in a manner that is
+   hard to profile. So, proper refcounting was added to atoms, and new
+   standard locking sequence is like following:
+
+       TXN_OBJECT *obj = ...;
+       TXN_ATOM   *atom;
+
+       spin_lock (& obj->_lock);
+
+       atom = obj->_atom;
+
+       if (! spin_trylock_atom (atom))
+         {
+           atomic_inc (& atom->refcount);
+           spin_unlock (& obj->_lock);
+           spin_lock (&atom->_lock);
+           atomic_dec (& atom->refcount);
+           // HERE atom is locked
+           spin_unlock (&atom->_lock);
+           RESTART OPERATION, THERE WAS A RACE;
+         }
+
+       ELSE YOU HAVE BOTH ATOM AND OBJ LOCKED
+
+   (core of this is implemented in trylock_throttle() function)
+
+   See the jnode_get_atom() function for a common case.
+
+   As an additional (and important) optimization allowing to avoid restarts,
+   it is possible to re-check required pre-conditions at the HERE point in
+   code above and proceed without restarting if they are still satisfied.
+*/
+
+/* An atomic transaction: this is the underlying system representation
+   of a transaction, not the one seen by clients.
+
+   Invariants involving this data-type:
+
+      [sb-fake-allocated]
+*/
+struct txn_atom {
+       /* The spinlock protecting the atom, held during fusion and various other state
+          changes. */
+       spinlock_t alock;
+
+       /* The atom's reference counter, increasing (in case of a duplication
+          of an existing reference or when we are sure that some other
+          reference exists) may be done without taking spinlock, decrementing
+          of the ref. counter requires a spinlock to be held.
+
+          Each transaction handle counts in ->refcount. All jnodes count as
+          one reference acquired in atom_begin_andlock(), released in
+          commit_current_atom().
+        */
+       atomic_t refcount;
+
+       /* The atom_id identifies the atom in persistent records such as the log. */
+       __u32 atom_id;
+
+       /* Flags holding any of the txn_flags enumerated values (e.g.,
+          ATOM_FORCE_COMMIT). */
+       __u32 flags;
+
+       /* Number of open handles. */
+       __u32 txnh_count;
+
+       /* The number of znodes captured by this atom.  Equal to the sum of lengths of the
+          dirty_nodes[level] and clean_nodes lists. */
+       __u32 capture_count;
+
+#if REISER4_DEBUG
+       int clean;
+       int dirty;
+       int ovrwr;
+       int wb;
+       int fq;
+#endif
+
+       __u32 flushed;
+
+       /* Current transaction stage. */
+       txn_stage stage;
+
+       /* Start time. */
+       unsigned long start_time;
+
+       /* The atom's delete set. It collects block numbers of the nodes
+          which were deleted during the transaction. */
+       struct list_head delete_set;
+
+       /* The atom's wandered_block mapping. */
+       struct list_head wandered_map;
+
+       /* The transaction's list of dirty captured nodes--per level.  Index
+          by (level). dirty_nodes[0] is for znode-above-root */
+       struct list_head dirty_nodes[REAL_MAX_ZTREE_HEIGHT + 1];
+
+       /* The transaction's list of clean captured nodes. */
+       struct list_head clean_nodes;
+
+       /* The atom's overwrite set */
+       struct list_head ovrwr_nodes;
+
+       /* nodes which are being written to disk */
+       struct list_head writeback_nodes;
+
+       /* list of inodes */
+       struct list_head inodes;
+
+       /* List of handles associated with this atom. */
+       struct list_head txnh_list;
+
+       /* Transaction list link: list of atoms in the transaction manager. */
+       struct list_head atom_link;
+
+       /* List of handles waiting FOR this atom: see 'capture_fuse_wait' comment. */
+       struct list_head fwaitfor_list;
+
+       /* List of this atom's handles that are waiting: see 'capture_fuse_wait' comment. */
+       struct list_head fwaiting_list;
+
+       /* Numbers of objects which were deleted/created in this transaction
+          thereby numbers of objects IDs which were released/deallocated. */
+       int nr_objects_deleted;
+       int nr_objects_created;
+       /* number of blocks allocated during the transaction */
+       __u64 nr_blocks_allocated;
+       /* All atom's flush queue objects are on this list  */
+       struct list_head flush_queues;
+#if REISER4_DEBUG
+       /* number of flush queues for this atom. */
+       int nr_flush_queues;
+       /* Number of jnodes which were removed from atom's lists and put
+          on flush_queue */
+       int num_queued;
+#endif
+       /* number of threads who wait for this atom to complete commit */
+       int nr_waiters;
+       /* number of threads which do jnode_flush() over this atom */
+       int nr_flushers;
+       /* number of flush queues which are IN_USE and jnodes from fq->prepped
+          are submitted to disk by the reiser4_write_fq() routine. */
+       int nr_running_queues;
+       /* A counter of grabbed unformatted nodes, see a description of the
+        * reiser4 space reservation scheme at block_alloc.c */
+       reiser4_block_nr flush_reserved;
+#if REISER4_DEBUG
+       void *committer;
+#endif
+       struct super_block *super;
+};
+
+#define ATOM_DIRTY_LIST(atom, level) (&(atom)->dirty_nodes[level])
+#define ATOM_CLEAN_LIST(atom) (&(atom)->clean_nodes)
+#define ATOM_OVRWR_LIST(atom) (&(atom)->ovrwr_nodes)
+#define ATOM_WB_LIST(atom) (&(atom)->writeback_nodes)
+#define ATOM_FQ_LIST(fq) (&(fq)->prepped)
+
+#define NODE_LIST(node) (node)->list
+#define ASSIGN_NODE_LIST(node, list) ON_DEBUG(NODE_LIST(node) = list)
+ON_DEBUG(void
+        count_jnode(txn_atom *, jnode *, atom_list old_list,
+                    atom_list new_list, int check_lists));
+
+typedef struct protected_jnodes {
+       struct list_head inatom; /* link to atom's list these structures */
+       struct list_head nodes; /* head of list of protected nodes */
+} protected_jnodes;
+
+/* A transaction handle: the client obtains and commits this handle which is assigned by
+   the system to a txn_atom. */
+struct txn_handle {
+       /* Spinlock protecting ->atom pointer */
+       spinlock_t hlock;
+
+       /* Flags for controlling commit_txnh() behavior */
+       /* from txn_handle_flags_t */
+       txn_handle_flags_t flags;
+
+       /* Whether it is READ_FUSING or WRITE_FUSING. */
+       txn_mode mode;
+
+       /* If assigned, the atom it is part of. */
+       txn_atom *atom;
+
+       /* Transaction list link. Head is in txn_atom. */
+       struct list_head txnh_link;
+};
+
+/* The transaction manager: one is contained in the reiser4_super_info_data */
+struct txn_mgr {
+       /* A spinlock protecting the atom list, id_count, flush_control */
+       spinlock_t tmgr_lock;
+
+       /* List of atoms. */
+       struct list_head atoms_list;
+
+       /* Number of atoms. */
+       int atom_count;
+
+       /* A counter used to assign atom->atom_id values. */
+       __u32 id_count;
+
+       /* a mutex object for commit serialization */
+       struct mutex commit_mutex;
+
+       /* a list of all txnmrgs served by particular daemon. */
+       struct list_head linkage;
+
+       /* description of daemon for this txnmgr */
+       ktxnmgrd_context *daemon;
+
+       /* parameters. Adjustable through mount options. */
+       unsigned int atom_max_size;
+       unsigned int atom_max_age;
+       unsigned int atom_min_size;
+       /* max number of concurrent flushers for one atom, 0 - unlimited.  */
+       unsigned int atom_max_flushers;
+       struct dentry *debugfs_atom_count;
+       struct dentry *debugfs_id_count;
+};
+
+/* FUNCTION DECLARATIONS */
+
+/* These are the externally (within Reiser4) visible transaction functions, therefore they
+   are prefixed with "txn_".  For comments, see txnmgr.c. */
+
+extern int init_txnmgr_static(void);
+extern void done_txnmgr_static(void);
+
+extern void reiser4_init_txnmgr(txn_mgr *);
+extern void reiser4_done_txnmgr(txn_mgr *);
+
+extern int reiser4_txn_reserve(int reserved);
+
+extern void reiser4_txn_begin(reiser4_context * context);
+extern int reiser4_txn_end(reiser4_context * context);
+
+extern void reiser4_txn_restart(reiser4_context * context);
+extern void reiser4_txn_restart_current(void);
+
+extern int txnmgr_force_commit_all(struct super_block *, int);
+extern int current_atom_should_commit(void);
+
+extern jnode *find_first_dirty_jnode(txn_atom *, int);
+
+extern int commit_some_atoms(txn_mgr *);
+extern int force_commit_atom(txn_handle *);
+extern int flush_current_atom(int, long, long *, txn_atom **, jnode *);
+
+extern int flush_some_atom(jnode *, long *, const struct writeback_control *, int);
+
+extern void reiser4_atom_set_stage(txn_atom * atom, txn_stage stage);
+
+extern int same_slum_check(jnode * base, jnode * check, int alloc_check,
+                          int alloc_value);
+extern void atom_dec_and_unlock(txn_atom * atom);
+
+extern int reiser4_try_capture(jnode * node, znode_lock_mode mode, txn_capture flags);
+extern int try_capture_page_to_invalidate(struct page *pg);
+
+extern void reiser4_uncapture_page(struct page *pg);
+extern void reiser4_uncapture_block(jnode *);
+extern void reiser4_uncapture_jnode(jnode *);
+
+extern int reiser4_capture_inode(struct inode *);
+extern int reiser4_uncapture_inode(struct inode *);
+
+extern txn_atom *get_current_atom_locked_nocheck(void);
+
+#if REISER4_DEBUG
+
+/**
+ * atom_is_protected - make sure that nobody but us can do anything with atom
+ * @atom: atom to be checked
+ *
+ * This is used to assert that atom either entered commit stages or is spin
+ * locked.
+ */
+static inline int atom_is_protected(txn_atom *atom)
+{
+       if (atom->stage >= ASTAGE_PRE_COMMIT)
+               return 1;
+       assert_spin_locked(&(atom->alock));
+       return 1;
+}
+
+#endif
+
+/* Get the current atom and spinlock it if current atom present. May not return NULL */
+static inline txn_atom *get_current_atom_locked(void)
+{
+       txn_atom *atom;
+
+       atom = get_current_atom_locked_nocheck();
+       assert("zam-761", atom != NULL);
+
+       return atom;
+}
+
+extern txn_atom *jnode_get_atom(jnode *);
+
+extern void reiser4_atom_wait_event(txn_atom *);
+extern void reiser4_atom_send_event(txn_atom *);
+
+extern void insert_into_atom_ovrwr_list(txn_atom * atom, jnode * node);
+extern int reiser4_capture_super_block(struct super_block *s);
+int capture_bulk(jnode **, int count);
+
+/* See the comment on the function blocknrset.c:blocknr_set_add for the
+   calling convention of these three routines. */
+extern void blocknr_set_init(struct list_head * bset);
+extern void blocknr_set_destroy(struct list_head * bset);
+extern void blocknr_set_merge(struct list_head * from, struct list_head * into);
+extern int blocknr_set_add_extent(txn_atom * atom,
+                                 struct list_head * bset,
+                                 blocknr_set_entry ** new_bsep,
+                                 const reiser4_block_nr * start,
+                                 const reiser4_block_nr * len);
+extern int blocknr_set_add_pair(txn_atom * atom, struct list_head * bset,
+                               blocknr_set_entry ** new_bsep,
+                               const reiser4_block_nr * a,
+                               const reiser4_block_nr * b);
+
+typedef int (*blocknr_set_actor_f) (txn_atom *, const reiser4_block_nr *,
+                                   const reiser4_block_nr *, void *);
+
+extern int blocknr_set_iterator(txn_atom * atom, struct list_head * bset,
+                               blocknr_set_actor_f actor, void *data,
+                               int delete);
+
+/* flush code takes care about how to fuse flush queues */
+extern void flush_init_atom(txn_atom * atom);
+extern void flush_fuse_queues(txn_atom * large, txn_atom * small);
+
+static inline void spin_lock_atom(txn_atom *atom)
+{
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(spin_locked_atom) &&
+                   LOCK_CNT_NIL(spin_locked_jnode) &&
+                   LOCK_CNT_NIL(spin_locked_zlock) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(rw_locked_tree)));
+
+       spin_lock(&(atom->alock));
+
+       LOCK_CNT_INC(spin_locked_atom);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline void spin_lock_atom_nested(txn_atom *atom)
+{
+       assert("", (LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(spin_locked_jnode) &&
+                   LOCK_CNT_NIL(spin_locked_zlock) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(rw_locked_tree)));
+
+       spin_lock_nested(&(atom->alock), SINGLE_DEPTH_NESTING);
+
+       LOCK_CNT_INC(spin_locked_atom);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline int spin_trylock_atom(txn_atom *atom)
+{
+       if (spin_trylock(&(atom->alock))) {
+               LOCK_CNT_INC(spin_locked_atom);
+               LOCK_CNT_INC(spin_locked);
+               return 1;
+       }
+       return 0;
+}
+
+static inline void spin_unlock_atom(txn_atom *atom)
+{
+       assert_spin_locked(&(atom->alock));
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_atom));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(spin_locked_atom);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&(atom->alock));
+}
+
+static inline void spin_lock_txnh(txn_handle *txnh)
+{
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(spin_locked_zlock) &&
+                   LOCK_CNT_NIL(rw_locked_tree)));
+
+       spin_lock(&(txnh->hlock));
+
+       LOCK_CNT_INC(spin_locked_txnh);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline int spin_trylock_txnh(txn_handle *txnh)
+{
+       if (spin_trylock(&(txnh->hlock))) {
+               LOCK_CNT_INC(spin_locked_txnh);
+               LOCK_CNT_INC(spin_locked);
+               return 1;
+       }
+       return 0;
+}
+
+static inline void spin_unlock_txnh(txn_handle *txnh)
+{
+       assert_spin_locked(&(txnh->hlock));
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_txnh));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(spin_locked_txnh);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&(txnh->hlock));
+}
+
+#define spin_ordering_pred_txnmgr(tmgr)                \
+       ( LOCK_CNT_NIL(spin_locked_atom) &&     \
+         LOCK_CNT_NIL(spin_locked_txnh) &&     \
+         LOCK_CNT_NIL(spin_locked_jnode) &&    \
+         LOCK_CNT_NIL(rw_locked_zlock) &&      \
+         LOCK_CNT_NIL(rw_locked_dk) &&         \
+         LOCK_CNT_NIL(rw_locked_tree) )
+
+static inline void spin_lock_txnmgr(txn_mgr *mgr)
+{
+       /* check that spinlocks of lower priorities are not held */
+       assert("", (LOCK_CNT_NIL(spin_locked_atom) &&
+                   LOCK_CNT_NIL(spin_locked_txnh) &&
+                   LOCK_CNT_NIL(spin_locked_jnode) &&
+                   LOCK_CNT_NIL(spin_locked_zlock) &&
+                   LOCK_CNT_NIL(rw_locked_dk) &&
+                   LOCK_CNT_NIL(rw_locked_tree)));
+
+       spin_lock(&(mgr->tmgr_lock));
+
+       LOCK_CNT_INC(spin_locked_txnmgr);
+       LOCK_CNT_INC(spin_locked);
+}
+
+static inline int spin_trylock_txnmgr(txn_mgr *mgr)
+{
+       if (spin_trylock(&(mgr->tmgr_lock))) {
+               LOCK_CNT_INC(spin_locked_txnmgr);
+               LOCK_CNT_INC(spin_locked);
+               return 1;
+       }
+       return 0;
+}
+
+static inline void spin_unlock_txnmgr(txn_mgr *mgr)
+{
+       assert_spin_locked(&(mgr->tmgr_lock));
+       assert("nikita-1375", LOCK_CNT_GTZ(spin_locked_txnmgr));
+       assert("nikita-1376", LOCK_CNT_GTZ(spin_locked));
+
+       LOCK_CNT_DEC(spin_locked_txnmgr);
+       LOCK_CNT_DEC(spin_locked);
+
+       spin_unlock(&(mgr->tmgr_lock));
+}
+
+typedef enum {
+       FQ_IN_USE = 0x1
+} flush_queue_state_t;
+
+typedef struct flush_queue flush_queue_t;
+
+/* This is an accumulator for jnodes prepared for writing to disk. A flush queue
+   is filled by the jnode_flush() routine, and written to disk under memory
+   pressure or at atom commit time. */
+/* LOCKING: fq state and fq->atom are protected by guard spinlock, fq->nr_queued
+   field and fq->prepped list can be modified if atom is spin-locked and fq
+   object is "in-use" state.  For read-only traversal of the fq->prepped list
+   and reading of the fq->nr_queued field it is enough to keep fq "in-use" or
+   only have atom spin-locked. */
+struct flush_queue {
+       /* linkage element is the first in this structure to make debugging
+          easier.  See field in atom struct for description of list. */
+       struct list_head alink;
+       /* A spinlock to protect changes of fq state and fq->atom pointer */
+       spinlock_t guard;
+       /* flush_queue state: [in_use | ready] */
+       flush_queue_state_t state;
+       /* A list which contains queued nodes, queued nodes are removed from any
+        * atom's list and put on this ->prepped one. */
+       struct list_head prepped;
+       /* number of submitted i/o requests */
+       atomic_t nr_submitted;
+       /* number of i/o errors */
+       atomic_t nr_errors;
+       /* An atom this flush queue is attached to */
+       txn_atom *atom;
+       /* A wait queue head to wait on i/o completion */
+       wait_queue_head_t wait;
+#if REISER4_DEBUG
+       /* A thread which took this fq in exclusive use, NULL if fq is free,
+        * used for debugging. */
+       struct task_struct *owner;
+#endif
+};
+
+extern int reiser4_fq_by_atom(txn_atom *, flush_queue_t **);
+extern void reiser4_fq_put_nolock(flush_queue_t *);
+extern void reiser4_fq_put(flush_queue_t *);
+extern void reiser4_fuse_fq(txn_atom * to, txn_atom * from);
+extern void queue_jnode(flush_queue_t *, jnode *);
+
+extern int reiser4_write_fq(flush_queue_t *, long *, int);
+extern int current_atom_finish_all_fq(void);
+extern void init_atom_fq_parts(txn_atom *);
+
+extern reiser4_block_nr txnmgr_count_deleted_blocks(void);
+
+extern void znode_make_dirty(znode * node);
+extern void jnode_make_dirty_locked(jnode * node);
+
+extern int reiser4_sync_atom(txn_atom * atom);
+
+#if REISER4_DEBUG
+extern int atom_fq_parts_are_clean(txn_atom *);
+#endif
+
+extern void add_fq_to_bio(flush_queue_t *, struct bio *);
+extern flush_queue_t *get_fq_for_current_atom(void);
+
+void protected_jnodes_init(protected_jnodes * list);
+void protected_jnodes_done(protected_jnodes * list);
+void reiser4_invalidate_list(struct list_head * head);
+
+# endif                                /* __REISER4_TXNMGR_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/type_safe_hash.h linux-2.6.20/fs/reiser4/type_safe_hash.h
--- linux-2.6.20.orig/fs/reiser4/type_safe_hash.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/type_safe_hash.h    2007-05-06 14:50:43.899038216 +0400
@@ -0,0 +1,320 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* A hash table class that uses hash chains (singly-linked) and is
+   parametrized to provide type safety.  */
+
+#ifndef __REISER4_TYPE_SAFE_HASH_H__
+#define __REISER4_TYPE_SAFE_HASH_H__
+
+#include "debug.h"
+
+#include <asm/errno.h>
+/* Step 1: Use TYPE_SAFE_HASH_DECLARE() to define the TABLE and LINK objects
+   based on the object type.  You need to declare the item type before
+   this definition, define it after this definition. */
+#define TYPE_SAFE_HASH_DECLARE(PREFIX,ITEM_TYPE)                                                     \
+                                                                                              \
+typedef struct PREFIX##_hash_table_  PREFIX##_hash_table;                                     \
+typedef struct PREFIX##_hash_link_   PREFIX##_hash_link;                                      \
+                                                                                              \
+struct PREFIX##_hash_table_                                                                   \
+{                                                                                             \
+  ITEM_TYPE  **_table;                                                                        \
+  __u32        _buckets;                                                                      \
+};                                                                                            \
+                                                                                              \
+struct PREFIX##_hash_link_                                                                    \
+{                                                                                             \
+  ITEM_TYPE *_next;                                                                           \
+}
+
+/* Step 2: Define the object type of the hash: give it field of type
+   PREFIX_hash_link. */
+
+/* Step 3: Use TYPE_SAFE_HASH_DEFINE to define the hash table interface using
+   the type and field name used in step 3.  The arguments are:
+
+   ITEM_TYPE    The item type being hashed
+   KEY_TYPE     The type of key being hashed
+   KEY_NAME     The name of the key field within the item
+   LINK_NAME    The name of the link field within the item, which you must make type PREFIX_hash_link)
+   HASH_FUNC    The name of the hash function (or macro, takes const pointer to key)
+   EQ_FUNC      The name of the equality function (or macro, takes const pointer to two keys)
+
+   It implements these functions:
+
+   prefix_hash_init           Initialize the table given its size.
+   prefix_hash_insert         Insert an item
+   prefix_hash_insert_index   Insert an item w/ precomputed hash_index
+   prefix_hash_find           Find an item by key
+   prefix_hash_find_index     Find an item w/ precomputed hash_index
+   prefix_hash_remove         Remove an item, returns 1 if found, 0 if not found
+   prefix_hash_remove_index   Remove an item w/ precomputed hash_index
+
+   If you'd like something to be done differently, feel free to ask me
+   for modifications.  Additional features that could be added but
+   have not been:
+
+   prefix_hash_remove_key           Find and remove an item by key
+   prefix_hash_remove_key_index     Find and remove an item by key w/ precomputed hash_index
+
+   The hash_function currently receives only the key as an argument,
+   meaning it must somehow know the number of buckets.  If this is a
+   problem let me know.
+
+   This hash table uses a single-linked hash chain.  This means
+   insertion is fast but deletion requires searching the chain.
+
+   There is also the doubly-linked hash chain approach, under which
+   deletion requires no search but the code is longer and it takes two
+   pointers per item.
+
+   The circularly-linked approach has the shortest code but requires
+   two pointers per bucket, doubling the size of the bucket array (in
+   addition to two pointers per item).
+*/
+#define TYPE_SAFE_HASH_DEFINE(PREFIX,ITEM_TYPE,KEY_TYPE,KEY_NAME,LINK_NAME,HASH_FUNC,EQ_FUNC)  \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_check_hash (PREFIX##_hash_table *table UNUSED_ARG,                            \
+                    __u32                hash UNUSED_ARG)                              \
+{                                                                                      \
+       assert("nikita-2780", hash < table->_buckets);                                  \
+}                                                                                      \
+                                                                                       \
+static __inline__ int                                                                  \
+PREFIX##_hash_init (PREFIX##_hash_table *hash,                                         \
+                   __u32                buckets)                                       \
+{                                                                                      \
+  hash->_table   = (ITEM_TYPE**) KMALLOC (sizeof (ITEM_TYPE*) * buckets);              \
+  hash->_buckets = buckets;                                                            \
+  if (hash->_table == NULL)                                                            \
+    {                                                                                  \
+      return RETERR(-ENOMEM);                                                          \
+    }                                                                                  \
+  memset (hash->_table, 0, sizeof (ITEM_TYPE*) * buckets);                             \
+  ON_DEBUG(printk(#PREFIX "_hash_table: %i buckets\n", buckets));                      \
+  return 0;                                                                            \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_done (PREFIX##_hash_table *hash)                                         \
+{                                                                                      \
+  if (REISER4_DEBUG && hash->_table != NULL) {                                          \
+           __u32 i;                                                                    \
+           for (i = 0 ; i < hash->_buckets ; ++ i)                                     \
+                   assert("nikita-2905", hash->_table[i] == NULL);                     \
+  }                                                                                     \
+  if (hash->_table != NULL)                                                            \
+    KFREE (hash->_table, sizeof (ITEM_TYPE*) * hash->_buckets);                                \
+  hash->_table = NULL;                                                                 \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_prefetch_next (ITEM_TYPE *item)                                          \
+{                                                                                      \
+       prefetch(item->LINK_NAME._next);                                                \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_prefetch_bucket (PREFIX##_hash_table *hash,                              \
+                              __u32                index)                              \
+{                                                                                      \
+       prefetch(hash->_table[index]);                                                  \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE*                                                           \
+PREFIX##_hash_find_index (PREFIX##_hash_table *hash,                                   \
+                         __u32                hash_index,                              \
+                         KEY_TYPE const      *find_key)                                \
+{                                                                                      \
+  ITEM_TYPE *item;                                                                     \
+                                                                                       \
+  PREFIX##_check_hash(hash, hash_index);                                               \
+                                                                                       \
+  for (item  = hash->_table[hash_index];                                               \
+       item != NULL;                                                                   \
+       item  = item->LINK_NAME._next)                                                  \
+    {                                                                                  \
+      prefetch(item->LINK_NAME._next);                                                 \
+      prefetch(item->LINK_NAME._next + offsetof(ITEM_TYPE, KEY_NAME));                 \
+      if (EQ_FUNC (& item->KEY_NAME, find_key))                                                \
+        {                                                                              \
+          return item;                                                                 \
+        }                                                                              \
+    }                                                                                  \
+                                                                                       \
+  return NULL;                                                                         \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE*                                                           \
+PREFIX##_hash_find_index_lru (PREFIX##_hash_table *hash,                               \
+                             __u32                hash_index,                          \
+                             KEY_TYPE const      *find_key)                            \
+{                                                                                      \
+  ITEM_TYPE ** item = &hash->_table[hash_index];                                        \
+                                                                                       \
+  PREFIX##_check_hash(hash, hash_index);                                               \
+                                                                                        \
+  while (*item != NULL) {                                                               \
+    prefetch(&(*item)->LINK_NAME._next);                                               \
+    if (EQ_FUNC (&(*item)->KEY_NAME, find_key)) {                                       \
+      ITEM_TYPE *found;                                                                \
+                                                                                       \
+      found = *item;                                                                   \
+      *item = found->LINK_NAME._next;                                                   \
+      found->LINK_NAME._next = hash->_table[hash_index];                               \
+      hash->_table[hash_index] = found;                                                        \
+      return found;                                                                     \
+    }                                                                                   \
+    item = &(*item)->LINK_NAME._next;                                                   \
+  }                                                                                    \
+  return NULL;                                                                         \
+}                                                                                      \
+                                                                                       \
+static __inline__ int                                                                  \
+PREFIX##_hash_remove_index (PREFIX##_hash_table *hash,                                 \
+                           __u32                hash_index,                            \
+                           ITEM_TYPE           *del_item)                              \
+{                                                                                      \
+  ITEM_TYPE ** hash_item_p = &hash->_table[hash_index];                                 \
+                                                                                       \
+  PREFIX##_check_hash(hash, hash_index);                                               \
+                                                                                        \
+  while (*hash_item_p != NULL) {                                                        \
+    prefetch(&(*hash_item_p)->LINK_NAME._next);                                                \
+    if (*hash_item_p == del_item) {                                                     \
+      *hash_item_p = (*hash_item_p)->LINK_NAME._next;                                   \
+      return 1;                                                                         \
+    }                                                                                   \
+    hash_item_p = &(*hash_item_p)->LINK_NAME._next;                                     \
+  }                                                                                    \
+  return 0;                                                                            \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_insert_index (PREFIX##_hash_table *hash,                                 \
+                           __u32                hash_index,                            \
+                           ITEM_TYPE           *ins_item)                              \
+{                                                                                      \
+  PREFIX##_check_hash(hash, hash_index);                                               \
+                                                                                       \
+  ins_item->LINK_NAME._next = hash->_table[hash_index];                                        \
+  hash->_table[hash_index]  = ins_item;                                                        \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_insert_index_rcu (PREFIX##_hash_table *hash,                             \
+                               __u32                hash_index,                        \
+                               ITEM_TYPE           *ins_item)                          \
+{                                                                                      \
+  PREFIX##_check_hash(hash, hash_index);                                               \
+                                                                                       \
+  ins_item->LINK_NAME._next = hash->_table[hash_index];                                        \
+  smp_wmb();                                                                           \
+  hash->_table[hash_index]  = ins_item;                                                        \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE*                                                           \
+PREFIX##_hash_find (PREFIX##_hash_table *hash,                                         \
+                   KEY_TYPE const      *find_key)                                      \
+{                                                                                      \
+  return PREFIX##_hash_find_index (hash, HASH_FUNC(hash, find_key), find_key);         \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE*                                                           \
+PREFIX##_hash_find_lru (PREFIX##_hash_table *hash,                                     \
+                       KEY_TYPE const      *find_key)                                  \
+{                                                                                      \
+  return PREFIX##_hash_find_index_lru (hash, HASH_FUNC(hash, find_key), find_key);     \
+}                                                                                      \
+                                                                                       \
+static __inline__ int                                                                  \
+PREFIX##_hash_remove (PREFIX##_hash_table *hash,                                       \
+                     ITEM_TYPE           *del_item)                                    \
+{                                                                                      \
+  return PREFIX##_hash_remove_index (hash,                                             \
+                                     HASH_FUNC(hash, &del_item->KEY_NAME), del_item);  \
+}                                                                                      \
+                                                                                       \
+static __inline__ int                                                                  \
+PREFIX##_hash_remove_rcu (PREFIX##_hash_table *hash,                                   \
+                     ITEM_TYPE           *del_item)                                    \
+{                                                                                      \
+  return PREFIX##_hash_remove (hash, del_item);                                                \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_insert (PREFIX##_hash_table *hash,                                       \
+                     ITEM_TYPE           *ins_item)                                    \
+{                                                                                      \
+  return PREFIX##_hash_insert_index (hash,                                             \
+                                     HASH_FUNC(hash, &ins_item->KEY_NAME), ins_item);  \
+}                                                                                      \
+                                                                                       \
+static __inline__ void                                                                 \
+PREFIX##_hash_insert_rcu (PREFIX##_hash_table *hash,                                   \
+                         ITEM_TYPE           *ins_item)                                \
+{                                                                                      \
+  return PREFIX##_hash_insert_index_rcu (hash, HASH_FUNC(hash, &ins_item->KEY_NAME),           \
+                                         ins_item);                                    \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE *                                                          \
+PREFIX##_hash_first (PREFIX##_hash_table *hash, __u32 ind)                             \
+{                                                                                      \
+  ITEM_TYPE *first;                                                                    \
+                                                                                       \
+  for (first = NULL; ind < hash->_buckets; ++ ind) {                                   \
+    first = hash->_table[ind];                                                         \
+    if (first != NULL)                                                                 \
+      break;                                                                           \
+  }                                                                                    \
+  return first;                                                                                \
+}                                                                                      \
+                                                                                       \
+static __inline__ ITEM_TYPE *                                                          \
+PREFIX##_hash_next (PREFIX##_hash_table *hash,                                         \
+                   ITEM_TYPE           *item)                                          \
+{                                                                                      \
+  ITEM_TYPE  *next;                                                                    \
+                                                                                       \
+  if (item == NULL)                                                                    \
+    return NULL;                                                                       \
+  next = item->LINK_NAME._next;                                                                \
+  if (next == NULL)                                                                    \
+    next = PREFIX##_hash_first (hash, HASH_FUNC(hash, &item->KEY_NAME) + 1);           \
+  return next;                                                                         \
+}                                                                                      \
+                                                                                       \
+typedef struct {} PREFIX##_hash_dummy
+
+#define for_all_ht_buckets(table, head)                                        \
+for ((head) = &(table) -> _table[ 0 ] ;                                        \
+     (head) != &(table) -> _table[ (table) -> _buckets ] ; ++ (head))
+
+#define for_all_in_bucket(bucket, item, next, field)                           \
+for ((item) = *(bucket), (next) = (item) ? (item) -> field._next : NULL ;      \
+     (item) != NULL ;                                                          \
+     (item) = (next), (next) = (item) ? (item) -> field._next : NULL )
+
+#define for_all_in_htable(table, prefix, item, next)   \
+for ((item) = prefix ## _hash_first ((table), 0),      \
+     (next) = prefix ## _hash_next ((table), (item)) ; \
+     (item) != NULL ;                                  \
+     (item) = (next),                                  \
+     (next) = prefix ## _hash_next ((table), (item)))
+
+/* __REISER4_TYPE_SAFE_HASH_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/vfs_ops.c linux-2.6.20/fs/reiser4/vfs_ops.c
--- linux-2.6.20.orig/fs/reiser4/vfs_ops.c      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/vfs_ops.c   2007-05-06 14:50:43.899038216 +0400
@@ -0,0 +1,259 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Interface to VFS. Reiser4 {super|export|dentry}_operations are defined
+   here. */
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "coord.h"
+#include "plugin/item/item.h"
+#include "plugin/file/file.h"
+#include "plugin/security/perm.h"
+#include "plugin/disk_format/disk_format.h"
+#include "plugin/plugin.h"
+#include "plugin/plugin_set.h"
+#include "plugin/object.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "vfs_ops.h"
+#include "inode.h"
+#include "page_cache.h"
+#include "ktxnmgrd.h"
+#include "super.h"
+#include "reiser4.h"
+#include "entd.h"
+#include "status_flags.h"
+#include "flush.h"
+#include "dscale.h"
+
+#include <linux/profile.h>
+#include <linux/types.h>
+#include <linux/mount.h>
+#include <linux/vfs.h>
+#include <linux/mm.h>
+#include <linux/buffer_head.h>
+#include <linux/dcache.h>
+#include <linux/list.h>
+#include <linux/pagemap.h>
+#include <linux/slab.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/writeback.h>
+#include <linux/blkdev.h>
+#include <linux/quotaops.h>
+#include <linux/security.h>
+#include <linux/reboot.h>
+#include <linux/rcupdate.h>
+
+/* update inode stat-data by calling plugin */
+int reiser4_update_sd(struct inode *object)
+{
+       file_plugin *fplug;
+
+       assert("nikita-2338", object != NULL);
+       /* check for read-only file system. */
+       if (IS_RDONLY(object))
+               return 0;
+
+       fplug = inode_file_plugin(object);
+       assert("nikita-2339", fplug != NULL);
+       return fplug->write_sd_by_inode(object);
+}
+
+/* helper function: increase inode nlink count and call plugin method to save
+   updated stat-data.
+
+   Used by link/create and during creation of dot and dotdot in mkdir
+*/
+int reiser4_add_nlink(struct inode *object /* object to which link is added */ ,
+                     struct inode *parent /* parent where new entry will be */
+                     ,
+                     int write_sd_p    /* true if stat-data has to be
+                                        * updated */ )
+{
+       file_plugin *fplug;
+       int result;
+
+       assert("nikita-1351", object != NULL);
+
+       fplug = inode_file_plugin(object);
+       assert("nikita-1445", fplug != NULL);
+
+       /* ask plugin whether it can add yet another link to this
+          object */
+       if (!fplug->can_add_link(object))
+               return RETERR(-EMLINK);
+
+       assert("nikita-2211", fplug->add_link != NULL);
+       /* call plugin to do actual addition of link */
+       result = fplug->add_link(object, parent);
+
+       /* optionally update stat data */
+       if (result == 0 && write_sd_p)
+               result = fplug->write_sd_by_inode(object);
+       return result;
+}
+
+/* helper function: decrease inode nlink count and call plugin method to save
+   updated stat-data.
+
+   Used by unlink/create
+*/
+int reiser4_del_nlink(struct inode *object     /* object from which link is
+                                                * removed */ ,
+                     struct inode *parent /* parent where entry was */ ,
+                     int write_sd_p    /* true is stat-data has to be
+                                        * updated */ )
+{
+       file_plugin *fplug;
+       int result;
+
+       assert("nikita-1349", object != NULL);
+
+       fplug = inode_file_plugin(object);
+       assert("nikita-1350", fplug != NULL);
+       assert("nikita-1446", object->i_nlink > 0);
+       assert("nikita-2210", fplug->rem_link != NULL);
+
+       /* call plugin to do actual deletion of link */
+       result = fplug->rem_link(object, parent);
+
+       /* optionally update stat data */
+       if (result == 0 && write_sd_p)
+               result = fplug->write_sd_by_inode(object);
+       return result;
+}
+
+/* Release reiser4 dentry. This is d_op->d_release() method. */
+static void reiser4_d_release(struct dentry *dentry /* dentry released */ )
+{
+       reiser4_free_dentry_fsdata(dentry);
+}
+
+/*
+ * Called by reiser4_sync_inodes(), during speculative write-back (through
+ * pdflush, or balance_dirty_pages()).
+ */
+void reiser4_writeout(struct super_block *sb, struct writeback_control *wbc)
+{
+       long written = 0;
+       int repeats = 0;
+       int result;
+       struct address_space *mapping;
+
+       /*
+        * Performs early flushing, trying to free some memory. If there is
+        * nothing to flush, commits some atoms.
+        */
+
+       /* Commit all atoms if reiser4_writepages() is called from sys_sync() or
+          sys_fsync(). */
+       if (wbc->sync_mode != WB_SYNC_NONE) {
+               txnmgr_force_commit_all(sb, 0);
+               return;
+       }
+
+       BUG_ON(reiser4_get_super_fake(sb) == NULL);
+       mapping = reiser4_get_super_fake(sb)->i_mapping;
+       do {
+               long nr_submitted = 0;
+               jnode *node = NULL;
+
+               /* do not put more requests to overload write queue */
+               if (wbc->nonblocking &&
+                   bdi_write_congested(mapping->backing_dev_info)) {
+                       blk_run_address_space(mapping);
+                       wbc->encountered_congestion = 1;
+                       break;
+               }
+               repeats++;
+               BUG_ON(wbc->nr_to_write <= 0);
+
+               if (get_current_context()->entd) {
+                       entd_context *ent = get_entd_context(sb);
+
+                       if (ent->cur_request->node)
+                               /*
+                                * this is ent thread and it managed to capture
+                                * requested page itself - start flush from
+                                * that page
+                                */
+                               node = jref(ent->cur_request->node);
+               }
+
+               result = flush_some_atom(node, &nr_submitted, wbc,
+                                        JNODE_FLUSH_WRITE_BLOCKS);
+               if (result != 0)
+                       warning("nikita-31001", "Flush failed: %i", result);
+               if (node)
+                       jput(node);
+               if (!nr_submitted)
+                       break;
+
+               wbc->nr_to_write -= nr_submitted;
+               written += nr_submitted;
+       } while (wbc->nr_to_write > 0);
+}
+
+void reiser4_throttle_write(struct inode *inode)
+{
+       reiser4_txn_restart_current();
+       balance_dirty_pages_ratelimited(inode->i_mapping);
+}
+
+const char *REISER4_SUPER_MAGIC_STRING = "ReIsEr4";
+const int REISER4_MAGIC_OFFSET = 16 * 4096;    /* offset to magic string from the
+                                                * beginning of device */
+
+/*
+ * Reiser4 initialization/shutdown.
+ *
+ * Code below performs global reiser4 initialization that is done either as
+ * part of kernel initialization (when reiser4 is statically built-in), or
+ * during reiser4 module load (when compiled as module).
+ */
+
+void reiser4_handle_error(void)
+{
+       struct super_block *sb = reiser4_get_current_sb();
+
+       if (!sb)
+               return;
+       reiser4_status_write(REISER4_STATUS_DAMAGED, 0,
+                            "Filesystem error occured");
+       switch (get_super_private(sb)->onerror) {
+       case 0:
+               reiser4_panic("foobar-42", "Filesystem error occured\n");
+       case 1:
+       default:
+               if (sb->s_flags & MS_RDONLY)
+                       return;
+               sb->s_flags |= MS_RDONLY;
+               break;
+       }
+}
+
+struct dentry_operations reiser4_dentry_operations = {
+       .d_revalidate = NULL,
+       .d_hash = NULL,
+       .d_compare = NULL,
+       .d_delete = NULL,
+       .d_release = reiser4_d_release,
+       .d_iput = NULL,
+};
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/vfs_ops.h linux-2.6.20/fs/reiser4/vfs_ops.h
--- linux-2.6.20.orig/fs/reiser4/vfs_ops.h      1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/vfs_ops.h   2007-05-06 14:50:43.899038216 +0400
@@ -0,0 +1,53 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* vfs_ops.c's exported symbols */
+
+#if !defined( __FS_REISER4_VFS_OPS_H__ )
+#define __FS_REISER4_VFS_OPS_H__
+
+#include "forward.h"
+#include "coord.h"
+#include "seal.h"
+#include "plugin/file/file.h"
+#include "super.h"
+#include "readahead.h"
+
+#include <linux/types.h>       /* for loff_t */
+#include <linux/fs.h>          /* for struct address_space */
+#include <linux/dcache.h>      /* for struct dentry */
+#include <linux/mm.h>
+#include <linux/backing-dev.h>
+
+/* address space operations */
+int reiser4_writepage(struct page *, struct writeback_control *);
+int reiser4_set_page_dirty(struct page *);
+void reiser4_invalidatepage(struct page *, unsigned long offset);
+int reiser4_releasepage(struct page *, gfp_t);
+
+extern int reiser4_update_sd(struct inode *);
+extern int reiser4_add_nlink(struct inode *, struct inode *, int);
+extern int reiser4_del_nlink(struct inode *, struct inode *, int);
+
+extern int reiser4_start_up_io(struct page *page);
+extern void reiser4_throttle_write(struct inode *);
+extern int jnode_is_releasable(jnode *);
+
+#define CAPTURE_APAGE_BURST (1024l)
+void reiser4_writeout(struct super_block *, struct writeback_control *);
+
+extern void reiser4_handle_error(void);
+
+/* __FS_REISER4_VFS_OPS_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/wander.c linux-2.6.20/fs/reiser4/wander.c
--- linux-2.6.20.orig/fs/reiser4/wander.c       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/wander.c    2007-05-06 14:50:43.903039466 +0400
@@ -0,0 +1,1797 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Reiser4 Wandering Log */
+
+/* You should read http://www.namesys.com/txn-doc.html
+
+   That describes how filesystem operations are performed as atomic
+   transactions, and how we try to arrange it so that we can write most of the
+   data only once while performing the operation atomically.
+
+   For the purposes of this code, it is enough for it to understand that it
+   has been told a given block should be written either once, or twice (if
+   twice then once to the wandered location and once to the real location).
+
+   This code guarantees that those blocks that are defined to be part of an
+   atom either all take effect or none of them take effect.
+
+   Relocate set nodes are submitted to write by the jnode_flush() routine, and
+   the overwrite set is submitted by reiser4_write_log().  This is because with
+   the overwrite set we seek to optimize writes, and with the relocate set we
+   seek to cause disk order to correlate with the parent first pre-order.
+
+   reiser4_write_log() allocates and writes wandered blocks and maintains
+   additional on-disk structures of the atom as wander records (each wander
+   record occupies one block) for storing of the "wandered map" (a table which
+   contains a relation between wandered and real block numbers) and other
+   information which might be needed at transaction recovery time.
+
+   The wander records are unidirectionally linked into a circle: each wander
+   record contains a block number of the next wander record, the last wander
+   record points to the first one.
+
+   One wander record (named "tx head" in this file) has a format which is
+   different from the other wander records. The "tx head" has a reference to the
+   "tx head" block of the previously committed atom.  Also, "tx head" contains
+   fs information (the free blocks counter, and the oid allocator state) which
+   is logged in a special way .
+
+   There are two journal control blocks, named journal header and journal
+   footer which have fixed on-disk locations.  The journal header has a
+   reference to the "tx head" block of the last committed atom.  The journal
+   footer points to the "tx head" of the last flushed atom.  The atom is
+   "played" when all blocks from its overwrite set are written to disk the
+   second time (i.e. written to their real locations).
+
+   NOTE: People who know reiserfs internals and its journal structure might be
+   confused with these terms journal footer and journal header. There is a table
+   with terms of similar semantics in reiserfs (reiser3) and reiser4:
+
+   REISER3 TERM        |  REISER4 TERM         | DESCRIPTION
+   --------------------+-----------------------+----------------------------
+   commit record       |  journal header       | atomic write of this record
+                       |                       | ends transaction commit
+   --------------------+-----------------------+----------------------------
+   journal header      |  journal footer       | atomic write of this record
+                       |                       | ends post-commit writes.
+                       |                       | After successful
+                       |                       | writing of this journal
+                       |                       | blocks (in reiser3) or
+                       |                       | wandered blocks/records are
+                       |                       | free for re-use.
+   --------------------+-----------------------+----------------------------
+
+   The atom commit process is the following:
+
+   1. The overwrite set is taken from atom's clean list, and its size is
+      counted.
+
+   2. The number of necessary wander records (including tx head) is calculated,
+      and the wander record blocks are allocated.
+
+   3. Allocate wandered blocks and populate wander records by wandered map.
+
+   4. submit write requests for wander records and wandered blocks.
+
+   5. wait until submitted write requests complete.
+
+   6. update journal header: change the pointer to the block number of just
+   written tx head, submit an i/o for modified journal header block and wait
+   for i/o completion.
+
+   NOTE: The special logging for bitmap blocks and some reiser4 super block
+   fields makes processes of atom commit, flush and recovering a bit more
+   complex (see comments in the source code for details).
+
+   The atom playing process is the following:
+
+   1. Write atom's overwrite set in-place.
+
+   2. Wait on i/o.
+
+   3. Update journal footer: change the pointer to block number of tx head
+   block of the atom we currently flushing, submit an i/o, wait on i/o
+   completion.
+
+   4. Free disk space which was used for wandered blocks and wander records.
+
+   After the freeing of wandered blocks and wander records we have that journal
+   footer points to the on-disk structure which might be overwritten soon.
+   Neither the log writer nor the journal recovery procedure use that pointer
+   for accessing the data.  When the journal recovery procedure finds the oldest
+   transaction it compares the journal footer pointer value with the "prev_tx"
+   pointer value in tx head, if values are equal the oldest not flushed
+   transaction is found.
+
+   NOTE on disk space leakage: the information about of what blocks and how many
+   blocks are allocated for wandered blocks, wandered records is not written to
+   the disk because of special logging for bitmaps and some super blocks
+   counters.  After a system crash we the reiser4 does not remember those
+   objects allocation, thus we have no such a kind of disk space leakage.
+*/
+
+/* Special logging of reiser4 super block fields. */
+
+/* There are some reiser4 super block fields (free block count and OID allocator
+   state (number of files and next free OID) which are logged separately from
+   super block to avoid unnecessary atom fusion.
+
+   So, the reiser4 super block can be not captured by a transaction with
+   allocates/deallocates disk blocks or create/delete file objects.  Moreover,
+   the reiser4 on-disk super block is not touched when such a transaction is
+   committed and flushed.  Those "counters logged specially" are logged in "tx
+   head" blocks and in the journal footer block.
+
+   A step-by-step description of special logging:
+
+   0. The per-atom information about deleted or created files and allocated or
+   freed blocks is collected during the transaction.  The atom's
+   ->nr_objects_created and ->nr_objects_deleted are for object
+   deletion/creation tracking, the numbers of allocated and freed blocks are
+   calculated using atom's delete set and atom's capture list -- all new and
+   relocated nodes should be on atom's clean list and should have JNODE_RELOC
+   bit set.
+
+   1. The "logged specially" reiser4 super block fields have their "committed"
+   versions in the reiser4 in-memory super block.  They get modified only at
+   atom commit time.  The atom's commit thread has an exclusive access to those
+   "committed" fields because the log writer implementation supports only one
+   atom commit a time (there is a per-fs "commit" mutex).  At
+   that time "committed" counters are modified using per-atom information
+   collected during the transaction. These counters are stored on disk as a
+   part of tx head block when atom is committed.
+
+   2. When the atom is flushed the value of the free block counter and the OID
+   allocator state get written to the journal footer block.  A special journal
+   procedure (journal_recover_sb_data()) takes those values from the journal
+   footer and updates the reiser4 in-memory super block.
+
+   NOTE: That means free block count and OID allocator state are logged
+   separately from the reiser4 super block regardless of the fact that the
+   reiser4 super block has fields to store both the free block counter and the
+   OID allocator.
+
+   Writing the whole super block at commit time requires knowing true values of
+   all its fields without changes made by not yet committed transactions. It is
+   possible by having their "committed" version of the super block like the
+   reiser4 bitmap blocks have "committed" and "working" versions.  However,
+   another scheme was implemented which stores special logged values in the
+   unused free space inside transaction head block.  In my opinion it has an
+   advantage of not writing whole super block when only part of it was
+   modified. */
+
+#include "debug.h"
+#include "dformat.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "page_cache.h"
+#include "wander.h"
+#include "reiser4.h"
+#include "super.h"
+#include "vfs_ops.h"
+#include "writeout.h"
+#include "inode.h"
+#include "entd.h"
+
+#include <linux/types.h>
+#include <linux/fs.h>          /* for struct super_block  */
+#include <linux/mm.h>          /* for struct page */
+#include <linux/pagemap.h>
+#include <linux/bio.h>         /* for struct bio */
+#include <linux/blkdev.h>
+
+static int write_jnodes_to_disk_extent(
+       jnode *, int, const reiser4_block_nr *, flush_queue_t *, int);
+
+/* The commit_handle is a container for objects needed at atom commit time  */
+struct commit_handle {
+       /* A pointer to atom's list of OVRWR nodes */
+       struct list_head *overwrite_set;
+       /* atom's overwrite set size */
+       int overwrite_set_size;
+       /* jnodes for wander record blocks */
+       struct list_head tx_list;
+       /* number of wander records */
+       __u32 tx_size;
+       /* 'committed' sb counters are saved here until atom is completely
+          flushed  */
+       __u64 free_blocks;
+       __u64 nr_files;
+       __u64 next_oid;
+       /* A pointer to the atom which is being committed */
+       txn_atom *atom;
+       /* A pointer to current super block */
+       struct super_block *super;
+       /* The counter of modified bitmaps */
+       reiser4_block_nr nr_bitmap;
+};
+
+static void init_commit_handle(struct commit_handle *ch, txn_atom *atom)
+{
+       memset(ch, 0, sizeof(struct commit_handle));
+       INIT_LIST_HEAD(&ch->tx_list);
+
+       ch->atom = atom;
+       ch->super = reiser4_get_current_sb();
+}
+
+static void done_commit_handle(struct commit_handle *ch)
+{
+       assert("zam-690", list_empty(&ch->tx_list));
+}
+
+static inline int reiser4_use_write_barrier(struct super_block * s)
+{
+       return !reiser4_is_set(s, REISER4_NO_WRITE_BARRIER);
+}
+
+static void disable_write_barrier(struct super_block * s)
+{
+       notice("zam-1055", "%s does not support write barriers,"
+              " using synchronous write instead.", s->s_id);
+       set_bit((int)REISER4_NO_WRITE_BARRIER, &get_super_private(s)->fs_flags);
+}
+
+/* fill journal header block data  */
+static void format_journal_header(struct commit_handle *ch)
+{
+       struct reiser4_super_info_data *sbinfo;
+       struct journal_header *header;
+       jnode *txhead;
+
+       sbinfo = get_super_private(ch->super);
+       assert("zam-479", sbinfo != NULL);
+       assert("zam-480", sbinfo->journal_header != NULL);
+
+       txhead = list_entry(ch->tx_list.next, jnode, capture_link);
+
+       jload(sbinfo->journal_header);
+
+       header = (struct journal_header *)jdata(sbinfo->journal_header);
+       assert("zam-484", header != NULL);
+
+       put_unaligned(cpu_to_le64(*jnode_get_block(txhead)),
+                     &header->last_committed_tx);
+
+       jrelse(sbinfo->journal_header);
+}
+
+/* fill journal footer block data */
+static void format_journal_footer(struct commit_handle *ch)
+{
+       struct reiser4_super_info_data *sbinfo;
+       struct journal_footer *footer;
+       jnode *tx_head;
+
+       sbinfo = get_super_private(ch->super);
+
+       tx_head = list_entry(ch->tx_list.next, jnode, capture_link);
+
+       assert("zam-493", sbinfo != NULL);
+       assert("zam-494", sbinfo->journal_header != NULL);
+
+       check_me("zam-691", jload(sbinfo->journal_footer) == 0);
+
+       footer = (struct journal_footer *)jdata(sbinfo->journal_footer);
+       assert("zam-495", footer != NULL);
+
+       put_unaligned(cpu_to_le64(*jnode_get_block(tx_head)),
+                     &footer->last_flushed_tx);
+       put_unaligned(cpu_to_le64(ch->free_blocks), &footer->free_blocks);
+
+       put_unaligned(cpu_to_le64(ch->nr_files), &footer->nr_files);
+       put_unaligned(cpu_to_le64(ch->next_oid), &footer->next_oid);
+
+       jrelse(sbinfo->journal_footer);
+}
+
+/* wander record capacity depends on current block size */
+static int wander_record_capacity(const struct super_block *super)
+{
+       return (super->s_blocksize -
+               sizeof(struct wander_record_header)) /
+           sizeof(struct wander_entry);
+}
+
+/* Fill first wander record (tx head) in accordance with supplied given data */
+static void format_tx_head(struct commit_handle *ch)
+{
+       jnode *tx_head;
+       jnode *next;
+       struct tx_header *header;
+
+       tx_head = list_entry(ch->tx_list.next, jnode, capture_link);
+       assert("zam-692", &ch->tx_list != &tx_head->capture_link);
+
+       next = list_entry(tx_head->capture_link.next, jnode, capture_link);
+       if (&ch->tx_list == &next->capture_link)
+               next = tx_head;
+
+       header = (struct tx_header *)jdata(tx_head);
+
+       assert("zam-460", header != NULL);
+       assert("zam-462", ch->super->s_blocksize >= sizeof(struct tx_header));
+
+       memset(jdata(tx_head), 0, (size_t) ch->super->s_blocksize);
+       memcpy(jdata(tx_head), TX_HEADER_MAGIC, TX_HEADER_MAGIC_SIZE);
+
+       put_unaligned(cpu_to_le32(ch->tx_size), &header->total);
+       put_unaligned(cpu_to_le64(get_super_private(ch->super)->last_committed_tx),
+                     &header->prev_tx);
+       put_unaligned(cpu_to_le64(*jnode_get_block(next)), &header->next_block);
+       put_unaligned(cpu_to_le64(ch->free_blocks), &header->free_blocks);
+       put_unaligned(cpu_to_le64(ch->nr_files), &header->nr_files);
+       put_unaligned(cpu_to_le64(ch->next_oid), &header->next_oid);
+}
+
+/* prepare ordinary wander record block (fill all service fields) */
+static void
+format_wander_record(struct commit_handle *ch, jnode *node, __u32 serial)
+{
+       struct wander_record_header *LRH;
+       jnode *next;
+
+       assert("zam-464", node != NULL);
+
+       LRH = (struct wander_record_header *)jdata(node);
+       next = list_entry(node->capture_link.next, jnode, capture_link);
+
+       if (&ch->tx_list == &next->capture_link)
+               next = list_entry(ch->tx_list.next, jnode, capture_link);
+
+       assert("zam-465", LRH != NULL);
+       assert("zam-463",
+              ch->super->s_blocksize > sizeof(struct wander_record_header));
+
+       memset(jdata(node), 0, (size_t) ch->super->s_blocksize);
+       memcpy(jdata(node), WANDER_RECORD_MAGIC, WANDER_RECORD_MAGIC_SIZE);
+
+       put_unaligned(cpu_to_le32(ch->tx_size), &LRH->total);
+       put_unaligned(cpu_to_le32(serial), &LRH->serial);
+       put_unaligned(cpu_to_le64(*jnode_get_block(next)), &LRH->next_block);
+}
+
+/* add one wandered map entry to formatted wander record */
+static void
+store_entry(jnode * node, int index, const reiser4_block_nr * a,
+           const reiser4_block_nr * b)
+{
+       char *data;
+       struct wander_entry *pairs;
+
+       data = jdata(node);
+       assert("zam-451", data != NULL);
+
+       pairs =
+           (struct wander_entry *)(data + sizeof(struct wander_record_header));
+
+       put_unaligned(cpu_to_le64(*a), &pairs[index].original);
+       put_unaligned(cpu_to_le64(*b), &pairs[index].wandered);
+}
+
+/* currently, wander records contains contain only wandered map, which depend on
+   overwrite set size */
+static void get_tx_size(struct commit_handle *ch)
+{
+       assert("zam-440", ch->overwrite_set_size != 0);
+       assert("zam-695", ch->tx_size == 0);
+
+       /* count all ordinary wander records
+          (<overwrite_set_size> - 1) / <wander_record_capacity> + 1 and add one
+          for tx head block */
+       ch->tx_size =
+           (ch->overwrite_set_size - 1) / wander_record_capacity(ch->super) +
+           2;
+}
+
+/* A special structure for using in store_wmap_actor() for saving its state
+   between calls */
+struct store_wmap_params {
+       jnode *cur;             /* jnode of current wander record to fill */
+       int idx;                /* free element index in wander record  */
+       int capacity;           /* capacity  */
+
+#if REISER4_DEBUG
+       struct list_head *tx_list;
+#endif
+};
+
+/* an actor for use in blocknr_set_iterator routine which populates the list
+   of pre-formatted wander records by wandered map info */
+static int
+store_wmap_actor(txn_atom * atom UNUSED_ARG, const reiser4_block_nr * a,
+                const reiser4_block_nr * b, void *data)
+{
+       struct store_wmap_params *params = data;
+
+       if (params->idx >= params->capacity) {
+               /* a new wander record should be taken from the tx_list */
+               params->cur = list_entry(params->cur->capture_link.next, jnode, capture_link);
+               assert("zam-454",
+                      params->tx_list != &params->cur->capture_link);
+
+               params->idx = 0;
+       }
+
+       store_entry(params->cur, params->idx, a, b);
+       params->idx++;
+
+       return 0;
+}
+
+/* This function is called after Relocate set gets written to disk, Overwrite
+   set is written to wandered locations and all wander records are written
+   also. Updated journal header blocks contains a pointer (block number) to
+   first wander record of the just written transaction */
+static int update_journal_header(struct commit_handle *ch, int use_barrier)
+{
+       struct reiser4_super_info_data *sbinfo = get_super_private(ch->super);
+       jnode *jh = sbinfo->journal_header;
+       jnode *head = list_entry(ch->tx_list.next, jnode, capture_link);
+       int ret;
+
+       format_journal_header(ch);
+
+       ret = write_jnodes_to_disk_extent(jh, 1, jnode_get_block(jh), NULL,
+                                         use_barrier ? WRITEOUT_BARRIER : 0);
+       if (ret)
+               return ret;
+
+       // blk_run_address_space(sbinfo->fake->i_mapping);
+       /*blk_run_queues(); */
+
+       ret = jwait_io(jh, WRITE);
+
+       if (ret)
+               return ret;
+
+       sbinfo->last_committed_tx = *jnode_get_block(head);
+
+       return 0;
+}
+
+/* This function is called after write-back is finished. We update journal
+   footer block and free blocks which were occupied by wandered blocks and
+   transaction wander records */
+static int update_journal_footer(struct commit_handle *ch, int use_barrier)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(ch->super);
+
+       jnode *jf = sbinfo->journal_footer;
+
+       int ret;
+
+       format_journal_footer(ch);
+
+       ret = write_jnodes_to_disk_extent(jf, 1, jnode_get_block(jf), NULL,
+                                         use_barrier ? WRITEOUT_BARRIER : 0);
+       if (ret)
+               return ret;
+
+       // blk_run_address_space(sbinfo->fake->i_mapping);
+       /*blk_run_queue(); */
+
+       ret = jwait_io(jf, WRITE);
+       if (ret)
+               return ret;
+
+       return 0;
+}
+
+/* free block numbers of wander records of already written in place transaction */
+static void dealloc_tx_list(struct commit_handle *ch)
+{
+       while (!list_empty(&ch->tx_list)) {
+               jnode *cur = list_entry(ch->tx_list.next, jnode, capture_link);
+               list_del(&cur->capture_link);
+               ON_DEBUG(INIT_LIST_HEAD(&cur->capture_link));
+               reiser4_dealloc_block(jnode_get_block(cur), BLOCK_NOT_COUNTED,
+                                     BA_FORMATTED);
+
+               unpin_jnode_data(cur);
+               reiser4_drop_io_head(cur);
+       }
+}
+
+/* An actor for use in block_nr_iterator() routine which frees wandered blocks
+   from atom's overwrite set. */
+static int
+dealloc_wmap_actor(txn_atom * atom UNUSED_ARG,
+                  const reiser4_block_nr * a UNUSED_ARG,
+                  const reiser4_block_nr * b, void *data UNUSED_ARG)
+{
+
+       assert("zam-499", b != NULL);
+       assert("zam-500", *b != 0);
+       assert("zam-501", !reiser4_blocknr_is_fake(b));
+
+       reiser4_dealloc_block(b, BLOCK_NOT_COUNTED, BA_FORMATTED);
+       return 0;
+}
+
+/* free wandered block locations of already written in place transaction */
+static void dealloc_wmap(struct commit_handle *ch)
+{
+       assert("zam-696", ch->atom != NULL);
+
+       blocknr_set_iterator(ch->atom, &ch->atom->wandered_map,
+                            dealloc_wmap_actor, NULL, 1);
+}
+
+/* helper function for alloc wandered blocks, which refill set of block
+   numbers needed for wandered blocks  */
+static int
+get_more_wandered_blocks(int count, reiser4_block_nr * start, int *len)
+{
+       reiser4_blocknr_hint hint;
+       int ret;
+
+       reiser4_block_nr wide_len = count;
+
+       /* FIXME-ZAM: A special policy needed for allocation of wandered blocks
+          ZAM-FIXME-HANS: yes, what happened to our discussion of using a fixed
+          reserved allocation area so as to get the best qualities of fixed
+          journals? */
+       reiser4_blocknr_hint_init(&hint);
+       hint.block_stage = BLOCK_GRABBED;
+
+       ret = reiser4_alloc_blocks(&hint, start, &wide_len,
+                                  BA_FORMATTED | BA_USE_DEFAULT_SEARCH_START);
+       *len = (int)wide_len;
+
+       return ret;
+}
+
+/*
+ * roll back changes made before issuing BIO in the case of IO error.
+ */
+static void undo_bio(struct bio *bio)
+{
+       int i;
+
+       for (i = 0; i < bio->bi_vcnt; ++i) {
+               struct page *pg;
+               jnode *node;
+
+               pg = bio->bi_io_vec[i].bv_page;
+               ClearPageWriteback(pg);
+               node = jprivate(pg);
+               spin_lock_jnode(node);
+               JF_CLR(node, JNODE_WRITEBACK);
+               JF_SET(node, JNODE_DIRTY);
+               spin_unlock_jnode(node);
+       }
+       bio_put(bio);
+}
+
+/* put overwrite set back to atom's clean list */
+static void put_overwrite_set(struct commit_handle *ch)
+{
+       jnode *cur;
+
+       list_for_each_entry(cur, ch->overwrite_set, capture_link)
+               jrelse_tail(cur);
+}
+
+/* Count overwrite set size, grab disk space for wandered blocks allocation.
+   Since we have a separate list for atom's overwrite set we just scan the list,
+   count bitmap and other not leaf nodes which wandered blocks allocation we
+   have to grab space for. */
+static int get_overwrite_set(struct commit_handle *ch)
+{
+       int ret;
+       jnode *cur;
+       __u64 nr_not_leaves = 0;
+#if REISER4_DEBUG
+       __u64 nr_formatted_leaves = 0;
+       __u64 nr_unformatted_leaves = 0;
+#endif
+
+       assert("zam-697", ch->overwrite_set_size == 0);
+
+       ch->overwrite_set = ATOM_OVRWR_LIST(ch->atom);
+       cur = list_entry(ch->overwrite_set->next, jnode, capture_link);
+
+       while (ch->overwrite_set != &cur->capture_link) {
+               jnode *next = list_entry(cur->capture_link.next, jnode, capture_link);
+
+               /* Count bitmap locks for getting correct statistics what number
+                * of blocks were cleared by the transaction commit. */
+               if (jnode_get_type(cur) == JNODE_BITMAP)
+                       ch->nr_bitmap++;
+
+               assert("zam-939", JF_ISSET(cur, JNODE_OVRWR)
+                      || jnode_get_type(cur) == JNODE_BITMAP);
+
+               if (jnode_is_znode(cur) && znode_above_root(JZNODE(cur))) {
+                       /* we replace fake znode by another (real)
+                          znode which is suggested by disk_layout
+                          plugin */
+
+                       /* FIXME: it looks like fake znode should be
+                          replaced by jnode supplied by
+                          disk_layout. */
+
+                       struct super_block *s = reiser4_get_current_sb();
+                       reiser4_super_info_data *sbinfo =
+                           get_current_super_private();
+
+                       if (sbinfo->df_plug->log_super) {
+                               jnode *sj = sbinfo->df_plug->log_super(s);
+
+                               assert("zam-593", sj != NULL);
+
+                               if (IS_ERR(sj))
+                                       return PTR_ERR(sj);
+
+                               spin_lock_jnode(sj);
+                               JF_SET(sj, JNODE_OVRWR);
+                               insert_into_atom_ovrwr_list(ch->atom, sj);
+                               spin_unlock_jnode(sj);
+
+                               /* jload it as the rest of overwrite set */
+                               jload_gfp(sj, reiser4_ctx_gfp_mask_get(), 0);
+
+                               ch->overwrite_set_size++;
+                       }
+                       spin_lock_jnode(cur);
+                       reiser4_uncapture_block(cur);
+                       jput(cur);
+
+               } else {
+                       int ret;
+                       ch->overwrite_set_size++;
+                       ret = jload_gfp(cur, reiser4_ctx_gfp_mask_get(), 0);
+                       if (ret)
+                               reiser4_panic("zam-783",
+                                             "cannot load e-flushed jnode back (ret = %d)\n",
+                                             ret);
+               }
+
+               /* Count not leaves here because we have to grab disk space
+                * for wandered blocks. They were not counted as "flush
+                * reserved". Counting should be done _after_ nodes are pinned
+                * into memory by jload(). */
+               if (!jnode_is_leaf(cur))
+                       nr_not_leaves++;
+               else {
+#if REISER4_DEBUG
+                       /* at this point @cur either has JNODE_FLUSH_RESERVED
+                        * or is eflushed. Locking is not strong enough to
+                        * write an assertion checking for this. */
+                       if (jnode_is_znode(cur))
+                               nr_formatted_leaves++;
+                       else
+                               nr_unformatted_leaves++;
+#endif
+                       JF_CLR(cur, JNODE_FLUSH_RESERVED);
+               }
+
+               cur = next;
+       }
+
+       /* Grab space for writing (wandered blocks) of not leaves found in
+        * overwrite set. */
+       ret = reiser4_grab_space_force(nr_not_leaves, BA_RESERVED);
+       if (ret)
+               return ret;
+
+       /* Disk space for allocation of wandered blocks of leaf nodes already
+        * reserved as "flush reserved", move it to grabbed space counter. */
+       spin_lock_atom(ch->atom);
+       assert("zam-940",
+              nr_formatted_leaves + nr_unformatted_leaves <=
+              ch->atom->flush_reserved);
+       flush_reserved2grabbed(ch->atom, ch->atom->flush_reserved);
+       spin_unlock_atom(ch->atom);
+
+       return ch->overwrite_set_size;
+}
+
+/**
+ * write_jnodes_to_disk_extent - submit write request
+ * @head:
+ * @first: first jnode of the list
+ * @nr: number of jnodes on the list
+ * @block_p:
+ * @fq:
+ * @flags: used to decide whether page is to get PG_reclaim flag
+ *
+ * Submits a write request for @nr jnodes beginning from the @first, other
+ * jnodes are after the @first on the double-linked "capture" list.  All jnodes
+ * will be written to the disk region of @nr blocks starting with @block_p block
+ * number.  If @fq is not NULL it means that waiting for i/o completion will be
+ * done more efficiently by using flush_queue_t objects.
+ * This function is the one which writes list of jnodes in batch mode. It does
+ * all low-level things as bio construction and page states manipulation.
+ *
+ * ZAM-FIXME-HANS: brief me on why this function exists, and why bios are
+ * aggregated in this function instead of being left to the layers below
+ *
+ * FIXME: ZAM->HANS: What layer are you talking about? Can you point me to that?
+ * Why that layer needed? Why BIOs cannot be constructed here?
+ */
+static int write_jnodes_to_disk_extent(
+       jnode *first, int nr, const reiser4_block_nr *block_p,
+       flush_queue_t *fq, int flags)
+{
+       struct super_block *super = reiser4_get_current_sb();
+       int write_op = ( flags & WRITEOUT_BARRIER ) ? WRITE_BARRIER : WRITE;
+       int max_blocks;
+       jnode *cur = first;
+       reiser4_block_nr block;
+
+       assert("zam-571", first != NULL);
+       assert("zam-572", block_p != NULL);
+       assert("zam-570", nr > 0);
+
+       block = *block_p;
+       max_blocks = min(bio_get_nr_vecs(super->s_bdev), BIO_MAX_PAGES);
+
+       while (nr > 0) {
+               struct bio *bio;
+               int nr_blocks = min(nr, max_blocks);
+               int i;
+               int nr_used;
+
+               bio = bio_alloc(GFP_NOIO, nr_blocks);
+               if (!bio)
+                       return RETERR(-ENOMEM);
+
+               bio->bi_bdev = super->s_bdev;
+               bio->bi_sector = block * (super->s_blocksize >> 9);
+               for (nr_used = 0, i = 0; i < nr_blocks; i++) {
+                       struct page *pg;
+
+                       pg = jnode_page(cur);
+                       assert("zam-573", pg != NULL);
+
+                       page_cache_get(pg);
+
+                       lock_and_wait_page_writeback(pg);
+
+                       if (!bio_add_page(bio, pg, super->s_blocksize, 0)) {
+                               /*
+                                * underlying device is satiated. Stop adding
+                                * pages to the bio.
+                                */
+                               unlock_page(pg);
+                               page_cache_release(pg);
+                               break;
+                       }
+
+                       spin_lock_jnode(cur);
+                       assert("nikita-3166",
+                              pg->mapping == jnode_get_mapping(cur));
+                       assert("zam-912", !JF_ISSET(cur, JNODE_WRITEBACK));
+#if REISER4_DEBUG
+                       spin_lock(&cur->load);
+                       assert("nikita-3165", !jnode_is_releasable(cur));
+                       spin_unlock(&cur->load);
+#endif
+                       JF_SET(cur, JNODE_WRITEBACK);
+                       JF_CLR(cur, JNODE_DIRTY);
+                       ON_DEBUG(cur->written++);
+                       spin_unlock_jnode(cur);
+
+                       ClearPageError(pg);
+                       set_page_writeback(pg);
+
+                       if (get_current_context()->entd) {
+                               /* this is ent thread */
+                               entd_context *ent = get_entd_context(super);
+                               struct wbq *rq, *next;
+
+                               spin_lock(&ent->guard);
+
+                               if (pg == ent->cur_request->page) {
+                                       /*
+                                        * entd is called for this page. This
+                                        * request is not in th etodo list
+                                        */
+                                       ent->cur_request->written = 1;
+                               } else {
+                                       /*
+                                        * if we have written a page for which writepage
+                                        * is called for - move request to another list.
+                                        */
+                                       list_for_each_entry_safe(rq, next, &ent->todo_list, link) {
+                                               assert("", rq->magic == WBQ_MAGIC);
+                                               if (pg == rq->page) {
+                                                       /*
+                                                        * remove request from
+                                                        * entd's queue, but do
+                                                        * not wake up a thread
+                                                        * which put this
+                                                        * request
+                                                        */
+                                                       list_del_init(&rq->link);
+                                                       ent->nr_todo_reqs --;
+                                                       list_add_tail(&rq->link, &ent->done_list);
+                                                       ent->nr_done_reqs ++;
+                                                       rq->written = 1;
+                                                       break;
+                                               }
+                                       }
+                               }
+                               spin_unlock(&ent->guard);
+                       }
+
+                       clear_page_dirty_for_io(pg);
+
+                       unlock_page(pg);
+
+                       cur = list_entry(cur->capture_link.next, jnode, capture_link);
+                       nr_used++;
+               }
+               if (nr_used > 0) {
+                       assert("nikita-3453",
+                              bio->bi_size == super->s_blocksize * nr_used);
+                       assert("nikita-3454", bio->bi_vcnt == nr_used);
+
+                       /* Check if we are allowed to write at all */
+                       if (super->s_flags & MS_RDONLY)
+                               undo_bio(bio);
+                       else {
+                               int not_supported;
+
+                               add_fq_to_bio(fq, bio);
+                               bio_get(bio);
+                               reiser4_submit_bio(write_op, bio);
+                               not_supported = bio_flagged(bio, BIO_EOPNOTSUPP);
+                               bio_put(bio);
+                               if (not_supported)
+                                       return -EOPNOTSUPP;
+                       }
+
+                       block += nr_used - 1;
+                       update_blocknr_hint_default(super, &block);
+                       block += 1;
+               } else {
+                       bio_put(bio);
+               }
+               nr -= nr_used;
+       }
+
+       return 0;
+}
+
+/* This is a procedure which recovers a contiguous sequences of disk block
+   numbers in the given list of j-nodes and submits write requests on this
+   per-sequence basis */
+int
+write_jnode_list(struct list_head *head, flush_queue_t *fq,
+                long *nr_submitted, int flags)
+{
+       int ret;
+       jnode *beg = list_entry(head->next, jnode, capture_link);
+
+       while (head != &beg->capture_link) {
+               int nr = 1;
+               jnode *cur = list_entry(beg->capture_link.next, jnode, capture_link);
+
+               while (head != &cur->capture_link) {
+                       if (*jnode_get_block(cur) != *jnode_get_block(beg) + nr)
+                               break;
+                       ++nr;
+                       cur = list_entry(cur->capture_link.next, jnode, capture_link);
+               }
+
+               ret = write_jnodes_to_disk_extent(
+                       beg, nr, jnode_get_block(beg), fq, flags);
+               if (ret)
+                       return ret;
+
+               if (nr_submitted)
+                       *nr_submitted += nr;
+
+               beg = cur;
+       }
+
+       return 0;
+}
+
+/* add given wandered mapping to atom's wandered map */
+static int
+add_region_to_wmap(jnode * cur, int len, const reiser4_block_nr * block_p)
+{
+       int ret;
+       blocknr_set_entry *new_bsep = NULL;
+       reiser4_block_nr block;
+
+       txn_atom *atom;
+
+       assert("zam-568", block_p != NULL);
+       block = *block_p;
+       assert("zam-569", len > 0);
+
+       while ((len--) > 0) {
+               do {
+                       atom = get_current_atom_locked();
+                       assert("zam-536",
+                              !reiser4_blocknr_is_fake(jnode_get_block(cur)));
+                       ret =
+                           blocknr_set_add_pair(atom, &atom->wandered_map,
+                                                &new_bsep,
+                                                jnode_get_block(cur), &block);
+               } while (ret == -E_REPEAT);
+
+               if (ret) {
+                       /* deallocate blocks which were not added to wandered
+                          map */
+                       reiser4_block_nr wide_len = len;
+
+                       reiser4_dealloc_blocks(&block, &wide_len,
+                                              BLOCK_NOT_COUNTED,
+                                              BA_FORMATTED
+                                              /* formatted, without defer */ );
+
+                       return ret;
+               }
+
+               spin_unlock_atom(atom);
+
+               cur = list_entry(cur->capture_link.next, jnode, capture_link);
+               ++block;
+       }
+
+       return 0;
+}
+
+/* Allocate wandered blocks for current atom's OVERWRITE SET and immediately
+   submit IO for allocated blocks.  We assume that current atom is in a stage
+   when any atom fusion is impossible and atom is unlocked and it is safe. */
+static int alloc_wandered_blocks(struct commit_handle *ch, flush_queue_t *fq)
+{
+       reiser4_block_nr block;
+
+       int rest;
+       int len;
+       int ret;
+
+       jnode *cur;
+
+       assert("zam-534", ch->overwrite_set_size > 0);
+
+       rest = ch->overwrite_set_size;
+
+       cur = list_entry(ch->overwrite_set->next, jnode, capture_link);
+       while (ch->overwrite_set != &cur->capture_link) {
+               assert("zam-567", JF_ISSET(cur, JNODE_OVRWR));
+
+               ret = get_more_wandered_blocks(rest, &block, &len);
+               if (ret)
+                       return ret;
+
+               rest -= len;
+
+               ret = add_region_to_wmap(cur, len, &block);
+               if (ret)
+                       return ret;
+
+               ret = write_jnodes_to_disk_extent(cur, len, &block, fq, 0);
+               if (ret)
+                       return ret;
+
+               while ((len--) > 0) {
+                       assert("zam-604",
+                              ch->overwrite_set != &cur->capture_link);
+                       cur = list_entry(cur->capture_link.next, jnode, capture_link);
+               }
+       }
+
+       return 0;
+}
+
+/* allocate given number of nodes over the journal area and link them into a
+   list, return pointer to the first jnode in the list */
+static int alloc_tx(struct commit_handle *ch, flush_queue_t * fq)
+{
+       reiser4_blocknr_hint hint;
+       reiser4_block_nr allocated = 0;
+       reiser4_block_nr first, len;
+       jnode *cur;
+       jnode *txhead;
+       int ret;
+       reiser4_context *ctx;
+       reiser4_super_info_data *sbinfo;
+
+       assert("zam-698", ch->tx_size > 0);
+       assert("zam-699", list_empty_careful(&ch->tx_list));
+
+       ctx = get_current_context();
+       sbinfo = get_super_private(ctx->super);
+
+       while (allocated < (unsigned)ch->tx_size) {
+               len = (ch->tx_size - allocated);
+
+               reiser4_blocknr_hint_init(&hint);
+
+               hint.block_stage = BLOCK_GRABBED;
+
+               /* FIXME: there should be some block allocation policy for
+                  nodes which contain wander records */
+
+               /* We assume that disk space for wandered record blocks can be
+                * taken from reserved area. */
+               ret = reiser4_alloc_blocks(&hint, &first, &len,
+                                          BA_FORMATTED | BA_RESERVED |
+                                          BA_USE_DEFAULT_SEARCH_START);
+               reiser4_blocknr_hint_done(&hint);
+
+               if (ret)
+                       return ret;
+
+               allocated += len;
+
+               /* create jnodes for all wander records */
+               while (len--) {
+                       cur = reiser4_alloc_io_head(&first);
+
+                       if (cur == NULL) {
+                               ret = RETERR(-ENOMEM);
+                               goto free_not_assigned;
+                       }
+
+                       ret = jinit_new(cur, reiser4_ctx_gfp_mask_get());
+
+                       if (ret != 0) {
+                               jfree(cur);
+                               goto free_not_assigned;
+                       }
+
+                       pin_jnode_data(cur);
+
+                       list_add_tail(&cur->capture_link, &ch->tx_list);
+
+                       first++;
+               }
+       }
+
+       { /* format a on-disk linked list of wander records */
+               int serial = 1;
+
+               txhead = list_entry(ch->tx_list.next, jnode, capture_link);
+               format_tx_head(ch);
+
+               cur = list_entry(txhead->capture_link.next, jnode, capture_link);
+               while (&ch->tx_list != &cur->capture_link) {
+                       format_wander_record(ch, cur, serial++);
+                       cur = list_entry(cur->capture_link.next, jnode, capture_link);
+               }
+       }
+
+       { /* Fill wander records with Wandered Set */
+               struct store_wmap_params params;
+               txn_atom *atom;
+
+               params.cur = list_entry(txhead->capture_link.next, jnode, capture_link);
+
+               params.idx = 0;
+               params.capacity =
+                   wander_record_capacity(reiser4_get_current_sb());
+
+               atom = get_current_atom_locked();
+               blocknr_set_iterator(atom, &atom->wandered_map,
+                                    &store_wmap_actor, &params, 0);
+               spin_unlock_atom(atom);
+       }
+
+       { /* relse all jnodes from tx_list */
+               cur = list_entry(ch->tx_list.next, jnode, capture_link);
+               while (&ch->tx_list != &cur->capture_link) {
+                       jrelse(cur);
+                       cur = list_entry(cur->capture_link.next, jnode, capture_link);
+               }
+       }
+
+       ret = write_jnode_list(&ch->tx_list, fq, NULL, 0);
+
+       return ret;
+
+      free_not_assigned:
+       /* We deallocate blocks not yet assigned to jnodes on tx_list. The
+          caller takes care about invalidating of tx list  */
+       reiser4_dealloc_blocks(&first, &len, BLOCK_NOT_COUNTED, BA_FORMATTED);
+
+       return ret;
+}
+
+static int commit_tx(struct commit_handle *ch)
+{
+       flush_queue_t *fq;
+       int barrier;
+       int ret;
+
+       /* Grab more space for wandered records. */
+       ret = reiser4_grab_space_force((__u64) (ch->tx_size), BA_RESERVED);
+       if (ret)
+               return ret;
+
+       fq = get_fq_for_current_atom();
+       if (IS_ERR(fq))
+               return PTR_ERR(fq);
+
+       spin_unlock_atom(fq->atom);
+       do {
+               ret = alloc_wandered_blocks(ch, fq);
+               if (ret)
+                       break;
+               ret = alloc_tx(ch, fq);
+               if (ret)
+                       break;
+       } while (0);
+
+       reiser4_fq_put(fq);
+       if (ret)
+               return ret;
+ repeat_wo_barrier:
+       barrier = reiser4_use_write_barrier(ch->super);
+       if (!barrier) {
+               ret = current_atom_finish_all_fq();
+               if (ret)
+                       return ret;
+       }
+       ret = update_journal_header(ch, barrier);
+       if (barrier) {
+               if (ret) {
+                       if (ret == -EOPNOTSUPP) {
+                               disable_write_barrier(ch->super);
+                               goto repeat_wo_barrier;
+                       }
+                       return ret;
+               }
+               ret = current_atom_finish_all_fq();
+       }
+       return ret;
+}
+
+static int write_tx_back(struct commit_handle * ch)
+{
+       flush_queue_t *fq;
+       int ret;
+       int barrier;
+
+       reiser4_post_commit_hook();
+       fq = get_fq_for_current_atom();
+       if (IS_ERR(fq))
+               return  PTR_ERR(fq);
+       spin_unlock_atom(fq->atom);
+       ret = write_jnode_list(
+               ch->overwrite_set, fq, NULL, WRITEOUT_FOR_PAGE_RECLAIM);
+       reiser4_fq_put(fq);
+       if (ret)
+               return ret;
+ repeat_wo_barrier:
+       barrier = reiser4_use_write_barrier(ch->super);
+       if (!barrier) {
+               ret = current_atom_finish_all_fq();
+               if (ret)
+                       return ret;
+       }
+       ret = update_journal_footer(ch, barrier);
+       if (barrier) {
+               if (ret) {
+                       if (ret == -EOPNOTSUPP) {
+                               disable_write_barrier(ch->super);
+                               goto repeat_wo_barrier;
+                       }
+                       return ret;
+               }
+               ret = current_atom_finish_all_fq();
+       }
+       if (ret)
+               return ret;
+       reiser4_post_write_back_hook();
+       return 0;
+}
+
+/* We assume that at this moment all captured blocks are marked as RELOC or
+   WANDER (belong to Relocate o Overwrite set), all nodes from Relocate set
+   are submitted to write.
+*/
+
+int reiser4_write_logs(long *nr_submitted)
+{
+       txn_atom *atom;
+       struct super_block *super = reiser4_get_current_sb();
+       reiser4_super_info_data *sbinfo = get_super_private(super);
+       struct commit_handle ch;
+       int ret;
+
+       writeout_mode_enable();
+
+       /* block allocator may add j-nodes to the clean_list */
+       ret = reiser4_pre_commit_hook();
+       if (ret)
+               return ret;
+
+       /* No locks are required if we take atom which stage >=
+        * ASTAGE_PRE_COMMIT */
+       atom = get_current_context()->trans->atom;
+       assert("zam-965", atom != NULL);
+
+       /* relocate set is on the atom->clean_nodes list after
+        * current_atom_complete_writes() finishes. It can be safely
+        * uncaptured after commit_mutex is locked, because any atom that
+        * captures these nodes is guaranteed to commit after current one.
+        *
+        * This can only be done after reiser4_pre_commit_hook(), because it is where
+        * early flushed jnodes with CREATED bit are transferred to the
+        * overwrite list. */
+       reiser4_invalidate_list(ATOM_CLEAN_LIST(atom));
+       spin_lock_atom(atom);
+       /* There might be waiters for the relocate nodes which we have
+        * released, wake them up. */
+       reiser4_atom_send_event(atom);
+       spin_unlock_atom(atom);
+
+       if (REISER4_DEBUG) {
+               int level;
+
+               for (level = 0; level < REAL_MAX_ZTREE_HEIGHT + 1; ++level)
+                       assert("nikita-3352",
+                              list_empty_careful(ATOM_DIRTY_LIST(atom, level)));
+       }
+
+       sbinfo->nr_files_committed += (unsigned)atom->nr_objects_created;
+       sbinfo->nr_files_committed -= (unsigned)atom->nr_objects_deleted;
+
+       init_commit_handle(&ch, atom);
+
+       ch.free_blocks = sbinfo->blocks_free_committed;
+       ch.nr_files = sbinfo->nr_files_committed;
+       /* ZAM-FIXME-HANS: email me what the contention level is for the super
+        * lock. */
+       ch.next_oid = oid_next(super);
+
+       /* count overwrite set and place it in a separate list */
+       ret = get_overwrite_set(&ch);
+
+       if (ret <= 0) {
+               /* It is possible that overwrite set is empty here, it means
+                  all captured nodes are clean */
+               goto up_and_ret;
+       }
+
+       /* Inform the caller about what number of dirty pages will be
+        * submitted to disk. */
+       *nr_submitted += ch.overwrite_set_size - ch.nr_bitmap;
+
+       /* count all records needed for storing of the wandered set */
+       get_tx_size(&ch);
+
+       ret = commit_tx(&ch);
+       if (ret)
+               goto up_and_ret;
+
+       spin_lock_atom(atom);
+       reiser4_atom_set_stage(atom, ASTAGE_POST_COMMIT);
+       spin_unlock_atom(atom);
+
+       ret = write_tx_back(&ch);
+       reiser4_post_write_back_hook();
+
+      up_and_ret:
+       if (ret) {
+               /* there could be fq attached to current atom; the only way to
+                  remove them is: */
+               current_atom_finish_all_fq();
+       }
+
+       /* free blocks of flushed transaction */
+       dealloc_tx_list(&ch);
+       dealloc_wmap(&ch);
+
+       put_overwrite_set(&ch);
+
+       done_commit_handle(&ch);
+
+       writeout_mode_disable();
+
+       return ret;
+}
+
+/* consistency checks for journal data/control blocks: header, footer, log
+   records, transactions head blocks. All functions return zero on success. */
+
+static int check_journal_header(const jnode * node UNUSED_ARG)
+{
+       /* FIXME: journal header has no magic field yet. */
+       return 0;
+}
+
+/* wait for write completion for all jnodes from given list */
+static int wait_on_jnode_list(struct list_head *head)
+{
+       jnode *scan;
+       int ret = 0;
+
+       list_for_each_entry(scan, head, capture_link) {
+               struct page *pg = jnode_page(scan);
+
+               if (pg) {
+                       if (PageWriteback(pg))
+                               wait_on_page_writeback(pg);
+
+                       if (PageError(pg))
+                               ret++;
+               }
+       }
+
+       return ret;
+}
+
+static int check_journal_footer(const jnode * node UNUSED_ARG)
+{
+       /* FIXME: journal footer has no magic field yet. */
+       return 0;
+}
+
+static int check_tx_head(const jnode * node)
+{
+       struct tx_header *header = (struct tx_header *)jdata(node);
+
+       if (memcmp(&header->magic, TX_HEADER_MAGIC, TX_HEADER_MAGIC_SIZE) != 0) {
+               warning("zam-627", "tx head at block %s corrupted\n",
+                       sprint_address(jnode_get_block(node)));
+               return RETERR(-EIO);
+       }
+
+       return 0;
+}
+
+static int check_wander_record(const jnode * node)
+{
+       struct wander_record_header *RH =
+           (struct wander_record_header *)jdata(node);
+
+       if (memcmp(&RH->magic, WANDER_RECORD_MAGIC, WANDER_RECORD_MAGIC_SIZE) !=
+           0) {
+               warning("zam-628", "wander record at block %s corrupted\n",
+                       sprint_address(jnode_get_block(node)));
+               return RETERR(-EIO);
+       }
+
+       return 0;
+}
+
+/* fill commit_handler structure by everything what is needed for update_journal_footer */
+static int restore_commit_handle(struct commit_handle *ch, jnode *tx_head)
+{
+       struct tx_header *TXH;
+       int ret;
+
+       ret = jload(tx_head);
+       if (ret)
+               return ret;
+
+       TXH = (struct tx_header *)jdata(tx_head);
+
+       ch->free_blocks = le64_to_cpu(get_unaligned(&TXH->free_blocks));
+       ch->nr_files = le64_to_cpu(get_unaligned(&TXH->nr_files));
+       ch->next_oid = le64_to_cpu(get_unaligned(&TXH->next_oid));
+
+       jrelse(tx_head);
+
+       list_add(&tx_head->capture_link, &ch->tx_list);
+
+       return 0;
+}
+
+/* replay one transaction: restore and write overwrite set in place */
+static int replay_transaction(const struct super_block *s,
+                             jnode * tx_head,
+                             const reiser4_block_nr * log_rec_block_p,
+                             const reiser4_block_nr * end_block,
+                             unsigned int nr_wander_records)
+{
+       reiser4_block_nr log_rec_block = *log_rec_block_p;
+       struct commit_handle ch;
+       LIST_HEAD(overwrite_set);
+       jnode *log;
+       int ret;
+
+       init_commit_handle(&ch, NULL);
+       ch.overwrite_set = &overwrite_set;
+
+       restore_commit_handle(&ch, tx_head);
+
+       while (log_rec_block != *end_block) {
+               struct wander_record_header *header;
+               struct wander_entry *entry;
+
+               int i;
+
+               if (nr_wander_records == 0) {
+                       warning("zam-631",
+                               "number of wander records in the linked list"
+                               " greater than number stored in tx head.\n");
+                       ret = RETERR(-EIO);
+                       goto free_ow_set;
+               }
+
+               log = reiser4_alloc_io_head(&log_rec_block);
+               if (log == NULL)
+                       return RETERR(-ENOMEM);
+
+               ret = jload(log);
+               if (ret < 0) {
+                       reiser4_drop_io_head(log);
+                       return ret;
+               }
+
+               ret = check_wander_record(log);
+               if (ret) {
+                       jrelse(log);
+                       reiser4_drop_io_head(log);
+                       return ret;
+               }
+
+               header = (struct wander_record_header *)jdata(log);
+               log_rec_block = le64_to_cpu(get_unaligned(&header->next_block));
+
+               entry = (struct wander_entry *)(header + 1);
+
+               /* restore overwrite set from wander record content */
+               for (i = 0; i < wander_record_capacity(s); i++) {
+                       reiser4_block_nr block;
+                       jnode *node;
+
+                       block = le64_to_cpu(get_unaligned(&entry->wandered));
+                       if (block == 0)
+                               break;
+
+                       node = reiser4_alloc_io_head(&block);
+                       if (node == NULL) {
+                               ret = RETERR(-ENOMEM);
+                               /*
+                                * FIXME-VS:???
+                                */
+                               jrelse(log);
+                               reiser4_drop_io_head(log);
+                               goto free_ow_set;
+                       }
+
+                       ret = jload(node);
+
+                       if (ret < 0) {
+                               reiser4_drop_io_head(node);
+                               /*
+                                * FIXME-VS:???
+                                */
+                               jrelse(log);
+                               reiser4_drop_io_head(log);
+                               goto free_ow_set;
+                       }
+
+                       block = le64_to_cpu(get_unaligned(&entry->original));
+
+                       assert("zam-603", block != 0);
+
+                       jnode_set_block(node, &block);
+
+                       list_add_tail(&node->capture_link, ch.overwrite_set);
+
+                       ++entry;
+               }
+
+               jrelse(log);
+               reiser4_drop_io_head(log);
+
+               --nr_wander_records;
+       }
+
+       if (nr_wander_records != 0) {
+               warning("zam-632", "number of wander records in the linked list"
+                       " less than number stored in tx head.\n");
+               ret = RETERR(-EIO);
+               goto free_ow_set;
+       }
+
+       {                       /* write wandered set in place */
+               write_jnode_list(ch.overwrite_set, NULL, NULL, 0);
+               ret = wait_on_jnode_list(ch.overwrite_set);
+
+               if (ret) {
+                       ret = RETERR(-EIO);
+                       goto free_ow_set;
+               }
+       }
+
+       ret = update_journal_footer(&ch, 0);
+
+      free_ow_set:
+
+       while (!list_empty(ch.overwrite_set)) {
+               jnode *cur = list_entry(ch.overwrite_set->next, jnode, capture_link);
+               list_del_init(&cur->capture_link);
+               jrelse(cur);
+               reiser4_drop_io_head(cur);
+       }
+
+       list_del_init(&tx_head->capture_link);
+
+       done_commit_handle(&ch);
+
+       return ret;
+}
+
+/* find oldest committed and not played transaction and play it. The transaction
+ * was committed and journal header block was updated but the blocks from the
+ * process of writing the atom's overwrite set in-place and updating of journal
+ * footer block were not completed. This function completes the process by
+ * recovering the atom's overwrite set from their wandered locations and writes
+ * them in-place and updating the journal footer. */
+static int replay_oldest_transaction(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+       jnode *jf = sbinfo->journal_footer;
+       unsigned int total;
+       struct journal_footer *F;
+       struct tx_header *T;
+
+       reiser4_block_nr prev_tx;
+       reiser4_block_nr last_flushed_tx;
+       reiser4_block_nr log_rec_block = 0;
+
+       jnode *tx_head;
+
+       int ret;
+
+       if ((ret = jload(jf)) < 0)
+               return ret;
+
+       F = (struct journal_footer *)jdata(jf);
+
+       last_flushed_tx = le64_to_cpu(get_unaligned(&F->last_flushed_tx));
+
+       jrelse(jf);
+
+       if (sbinfo->last_committed_tx == last_flushed_tx) {
+               /* all transactions are replayed */
+               return 0;
+       }
+
+       prev_tx = sbinfo->last_committed_tx;
+
+       /* searching for oldest not flushed transaction */
+       while (1) {
+               tx_head = reiser4_alloc_io_head(&prev_tx);
+               if (!tx_head)
+                       return RETERR(-ENOMEM);
+
+               ret = jload(tx_head);
+               if (ret < 0) {
+                       reiser4_drop_io_head(tx_head);
+                       return ret;
+               }
+
+               ret = check_tx_head(tx_head);
+               if (ret) {
+                       jrelse(tx_head);
+                       reiser4_drop_io_head(tx_head);
+                       return ret;
+               }
+
+               T = (struct tx_header *)jdata(tx_head);
+
+               prev_tx = le64_to_cpu(get_unaligned(&T->prev_tx));
+
+               if (prev_tx == last_flushed_tx)
+                       break;
+
+               jrelse(tx_head);
+               reiser4_drop_io_head(tx_head);
+       }
+
+       total = le32_to_cpu(get_unaligned(&T->total));
+       log_rec_block = le64_to_cpu(get_unaligned(&T->next_block));
+
+       pin_jnode_data(tx_head);
+       jrelse(tx_head);
+
+       ret =
+           replay_transaction(s, tx_head, &log_rec_block,
+                              jnode_get_block(tx_head), total - 1);
+
+       unpin_jnode_data(tx_head);
+       reiser4_drop_io_head(tx_head);
+
+       if (ret)
+               return ret;
+       return -E_REPEAT;
+}
+
+/* The reiser4 journal current implementation was optimized to not to capture
+   super block if certain super blocks fields are modified. Currently, the set
+   is (<free block count>, <OID allocator>). These fields are logged by
+   special way which includes storing them in each transaction head block at
+   atom commit time and writing that information to journal footer block at
+   atom flush time.  For getting info from journal footer block to the
+   in-memory super block there is a special function
+   reiser4_journal_recover_sb_data() which should be called after disk format
+   plugin re-reads super block after journal replaying.
+*/
+
+/* get the information from journal footer in-memory super block */
+int reiser4_journal_recover_sb_data(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+       struct journal_footer *jf;
+       int ret;
+
+       assert("zam-673", sbinfo->journal_footer != NULL);
+
+       ret = jload(sbinfo->journal_footer);
+       if (ret != 0)
+               return ret;
+
+       ret = check_journal_footer(sbinfo->journal_footer);
+       if (ret != 0)
+               goto out;
+
+       jf = (struct journal_footer *)jdata(sbinfo->journal_footer);
+
+       /* was there at least one flushed transaction?  */
+       if (jf->last_flushed_tx) {
+
+               /* restore free block counter logged in this transaction */
+               reiser4_set_free_blocks(s, le64_to_cpu(get_unaligned(&jf->free_blocks)));
+
+               /* restore oid allocator state */
+               oid_init_allocator(s,
+                                  le64_to_cpu(get_unaligned(&jf->nr_files)),
+                                  le64_to_cpu(get_unaligned(&jf->next_oid)));
+       }
+      out:
+       jrelse(sbinfo->journal_footer);
+       return ret;
+}
+
+/* reiser4 replay journal procedure */
+int reiser4_journal_replay(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+       jnode *jh, *jf;
+       struct journal_header *header;
+       int nr_tx_replayed = 0;
+       int ret;
+
+       assert("zam-582", sbinfo != NULL);
+
+       jh = sbinfo->journal_header;
+       jf = sbinfo->journal_footer;
+
+       if (!jh || !jf) {
+               /* it is possible that disk layout does not support journal
+                  structures, we just warn about this */
+               warning("zam-583",
+                       "journal control blocks were not loaded by disk layout plugin.  "
+                       "journal replaying is not possible.\n");
+               return 0;
+       }
+
+       /* Take free block count from journal footer block. The free block
+          counter value corresponds the last flushed transaction state */
+       ret = jload(jf);
+       if (ret < 0)
+               return ret;
+
+       ret = check_journal_footer(jf);
+       if (ret) {
+               jrelse(jf);
+               return ret;
+       }
+
+       jrelse(jf);
+
+       /* store last committed transaction info in reiser4 in-memory super
+          block */
+       ret = jload(jh);
+       if (ret < 0)
+               return ret;
+
+       ret = check_journal_header(jh);
+       if (ret) {
+               jrelse(jh);
+               return ret;
+       }
+
+       header = (struct journal_header *)jdata(jh);
+       sbinfo->last_committed_tx = le64_to_cpu(get_unaligned(&header->last_committed_tx));
+
+       jrelse(jh);
+
+       /* replay committed transactions */
+       while ((ret = replay_oldest_transaction(s)) == -E_REPEAT)
+               nr_tx_replayed++;
+
+       return ret;
+}
+
+/* load journal control block (either journal header or journal footer block) */
+static int
+load_journal_control_block(jnode ** node, const reiser4_block_nr * block)
+{
+       int ret;
+
+       *node = reiser4_alloc_io_head(block);
+       if (!(*node))
+               return RETERR(-ENOMEM);
+
+       ret = jload(*node);
+
+       if (ret) {
+               reiser4_drop_io_head(*node);
+               *node = NULL;
+               return ret;
+       }
+
+       pin_jnode_data(*node);
+       jrelse(*node);
+
+       return 0;
+}
+
+/* unload journal header or footer and free jnode */
+static void unload_journal_control_block(jnode ** node)
+{
+       if (*node) {
+               unpin_jnode_data(*node);
+               reiser4_drop_io_head(*node);
+               *node = NULL;
+       }
+}
+
+/* release journal control blocks */
+void reiser4_done_journal_info(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+
+       assert("zam-476", sbinfo != NULL);
+
+       unload_journal_control_block(&sbinfo->journal_header);
+       unload_journal_control_block(&sbinfo->journal_footer);
+       rcu_barrier();
+}
+
+/* load journal control blocks */
+int reiser4_init_journal_info(struct super_block *s)
+{
+       reiser4_super_info_data *sbinfo = get_super_private(s);
+       journal_location *loc;
+       int ret;
+
+       loc = &sbinfo->jloc;
+
+       assert("zam-651", loc != NULL);
+       assert("zam-652", loc->header != 0);
+       assert("zam-653", loc->footer != 0);
+
+       ret = load_journal_control_block(&sbinfo->journal_header, &loc->header);
+
+       if (ret)
+               return ret;
+
+       ret = load_journal_control_block(&sbinfo->journal_footer, &loc->footer);
+
+       if (ret) {
+               unload_journal_control_block(&sbinfo->journal_header);
+       }
+
+       return ret;
+}
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/wander.h linux-2.6.20/fs/reiser4/wander.h
--- linux-2.6.20.orig/fs/reiser4/wander.h       1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/wander.h    2007-05-06 14:50:43.903039466 +0400
@@ -0,0 +1,135 @@
+/* Copyright 2002, 2003 by Hans Reiser, licensing governed by reiser4/README */
+
+#if !defined (__FS_REISER4_WANDER_H__)
+#define __FS_REISER4_WANDER_H__
+
+#include "dformat.h"
+
+#include <linux/fs.h>          /* for struct super_block  */
+
+/* REISER4 JOURNAL ON-DISK DATA STRUCTURES   */
+
+#define TX_HEADER_MAGIC  "TxMagic4"
+#define WANDER_RECORD_MAGIC "LogMagc4"
+
+#define TX_HEADER_MAGIC_SIZE  (8)
+#define WANDER_RECORD_MAGIC_SIZE (8)
+
+/* journal header block format */
+struct journal_header {
+       /* last written transaction head location */
+       d64 last_committed_tx;
+};
+
+typedef struct journal_location {
+       reiser4_block_nr footer;
+       reiser4_block_nr header;
+} journal_location;
+
+/* The wander.c head comment describes usage and semantic of all these structures */
+/* journal footer block format */
+struct journal_footer {
+       /* last flushed transaction location. */
+       /* This block number is no more valid after the transaction it points
+          to gets flushed, this number is used only at journal replaying time
+          for detection of the end of on-disk list of committed transactions
+          which were not flushed completely */
+       d64 last_flushed_tx;
+
+       /* free block counter is written in journal footer at transaction
+          flushing , not in super block because free blocks counter is logged
+          by another way than super block fields (root pointer, for
+          example). */
+       d64 free_blocks;
+
+       /* number of used OIDs and maximal used OID are logged separately from
+          super block */
+       d64 nr_files;
+       d64 next_oid;
+};
+
+/* Each wander record (except the first one) has unified format with wander
+   record header followed by an array of log entries */
+struct wander_record_header {
+       /* when there is no predefined location for wander records, this magic
+          string should help reiser4fsck. */
+       char magic[WANDER_RECORD_MAGIC_SIZE];
+
+       /* transaction id */
+       d64 id;
+
+       /* total number of wander records in current transaction  */
+       d32 total;
+
+       /* this block number in transaction */
+       d32 serial;
+
+       /* number of previous block in commit */
+       d64 next_block;
+};
+
+/* The first wander record (transaction head) of written transaction has the
+   special format */
+struct tx_header {
+       /* magic string makes first block in transaction different from other
+          logged blocks, it should help fsck. */
+       char magic[TX_HEADER_MAGIC_SIZE];
+
+       /* transaction id */
+       d64 id;
+
+       /* total number of records (including this first tx head) in the
+          transaction */
+       d32 total;
+
+       /* align next field to 8-byte boundary; this field always is zero */
+       d32 padding;
+
+       /* block number of previous transaction head */
+       d64 prev_tx;
+
+       /* next wander record location */
+       d64 next_block;
+
+       /* committed versions of free blocks counter */
+       d64 free_blocks;
+
+       /* number of used OIDs (nr_files) and maximal used OID are logged
+          separately from super block */
+       d64 nr_files;
+       d64 next_oid;
+};
+
+/* A transaction gets written to disk as a set of wander records (each wander
+   record size is fs block) */
+
+/* As it was told above a wander The rest of wander record is filled by these log entries, unused space filled
+   by zeroes */
+struct wander_entry {
+       d64 original;           /* block original location */
+       d64 wandered;           /* block wandered location */
+};
+
+/* REISER4 JOURNAL WRITER FUNCTIONS   */
+
+extern int reiser4_write_logs(long *);
+extern int reiser4_journal_replay(struct super_block *);
+extern int reiser4_journal_recover_sb_data(struct super_block *);
+
+extern int reiser4_init_journal_info(struct super_block *);
+extern void reiser4_done_journal_info(struct super_block *);
+
+extern int write_jnode_list(struct list_head *, flush_queue_t *, long *, int);
+
+#endif                         /* __FS_REISER4_WANDER_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   scroll-step: 1
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/writeout.h linux-2.6.20/fs/reiser4/writeout.h
--- linux-2.6.20.orig/fs/reiser4/writeout.h     1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/writeout.h  2007-05-06 14:50:43.907040716 +0400
@@ -0,0 +1,21 @@
+/* Copyright 2002, 2003, 2004 by Hans Reiser, licensing governed by reiser4/README  */
+
+#if !defined (__FS_REISER4_WRITEOUT_H__)
+
+#define WRITEOUT_SINGLE_STREAM (0x1)
+#define WRITEOUT_FOR_PAGE_RECLAIM  (0x2)
+#define WRITEOUT_BARRIER (0x4)
+
+extern int reiser4_get_writeout_flags(void);
+
+#endif                         /* __FS_REISER4_WRITEOUT_H__ */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 80
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/znode.c linux-2.6.20/fs/reiser4/znode.c
--- linux-2.6.20.orig/fs/reiser4/znode.c        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/znode.c     2007-05-06 14:50:43.907040716 +0400
@@ -0,0 +1,1029 @@
+/* Copyright 2001, 2002, 2003 by Hans Reiser, licensing governed by
+ * reiser4/README */
+/* Znode manipulation functions. */
+/* Znode is the in-memory header for a tree node. It is stored
+   separately from the node itself so that it does not get written to
+   disk.  In this respect znode is like buffer head or page head. We
+   also use znodes for additional reiser4 specific purposes:
+
+    . they are organized into tree structure which is a part of whole
+      reiser4 tree.
+    . they are used to implement node grained locking
+    . they are used to keep additional state associated with a
+      node
+    . they contain links to lists used by the transaction manager
+
+   Znode is attached to some variable "block number" which is instance of
+   fs/reiser4/tree.h:reiser4_block_nr type. Znode can exist without
+   appropriate node being actually loaded in memory. Existence of znode itself
+   is regulated by reference count (->x_count) in it. Each time thread
+   acquires reference to znode through call to zget(), ->x_count is
+   incremented and decremented on call to zput().  Data (content of node) are
+   brought in memory through call to zload(), which also increments ->d_count
+   reference counter.  zload can block waiting on IO.  Call to zrelse()
+   decreases this counter. Also, ->c_count keeps track of number of child
+   znodes and prevents parent znode from being recycled until all of its
+   children are. ->c_count is decremented whenever child goes out of existence
+   (being actually recycled in zdestroy()) which can be some time after last
+   reference to this child dies if we support some form of LRU cache for
+   znodes.
+
+*/
+/* EVERY ZNODE'S STORY
+
+   1. His infancy.
+
+   Once upon a time, the znode was born deep inside of zget() by call to
+   zalloc(). At the return from zget() znode had:
+
+    . reference counter (x_count) of 1
+    . assigned block number, marked as used in bitmap
+    . pointer to parent znode. Root znode parent pointer points
+      to its father: "fake" znode. This, in turn, has NULL parent pointer.
+    . hash table linkage
+    . no data loaded from disk
+    . no node plugin
+    . no sibling linkage
+
+   2. His childhood
+
+   Each node is either brought into memory as a result of tree traversal, or
+   created afresh, creation of the root being a special case of the latter. In
+   either case it's inserted into sibling list. This will typically require
+   some ancillary tree traversing, but ultimately both sibling pointers will
+   exist and JNODE_LEFT_CONNECTED and JNODE_RIGHT_CONNECTED will be true in
+   zjnode.state.
+
+   3. His youth.
+
+   If znode is bound to already existing node in a tree, its content is read
+   from the disk by call to zload(). At that moment, JNODE_LOADED bit is set
+   in zjnode.state and zdata() function starts to return non null for this
+   znode. zload() further calls zparse() that determines which node layout
+   this node is rendered in, and sets ->nplug on success.
+
+   If znode is for new node just created, memory for it is allocated and
+   zinit_new() function is called to initialise data, according to selected
+   node layout.
+
+   4. His maturity.
+
+   After this point, znode lingers in memory for some time. Threads can
+   acquire references to znode either by blocknr through call to zget(), or by
+   following a pointer to unallocated znode from internal item. Each time
+   reference to znode is obtained, x_count is increased. Thread can read/write
+   lock znode. Znode data can be loaded through calls to zload(), d_count will
+   be increased appropriately. If all references to znode are released
+   (x_count drops to 0), znode is not recycled immediately. Rather, it is
+   still cached in the hash table in the hope that it will be accessed
+   shortly.
+
+   There are two ways in which znode existence can be terminated:
+
+    . sudden death: node bound to this znode is removed from the tree
+    . overpopulation: znode is purged out of memory due to memory pressure
+
+   5. His death.
+
+   Death is complex process.
+
+   When we irrevocably commit ourselves to decision to remove node from the
+   tree, JNODE_HEARD_BANSHEE bit is set in zjnode.state of corresponding
+   znode. This is done either in ->kill_hook() of internal item or in
+   reiser4_kill_root() function when tree root is removed.
+
+   At this moment znode still has:
+
+    . locks held on it, necessary write ones
+    . references to it
+    . disk block assigned to it
+    . data loaded from the disk
+    . pending requests for lock
+
+   But once JNODE_HEARD_BANSHEE bit set, last call to unlock_znode() does node
+   deletion. Node deletion includes two phases. First all ways to get
+   references to that znode (sibling and parent links and hash lookup using
+   block number stored in parent node) should be deleted -- it is done through
+   sibling_list_remove(), also we assume that nobody uses down link from
+   parent node due to its nonexistence or proper parent node locking and
+   nobody uses parent pointers from children due to absence of them. Second we
+   invalidate all pending lock requests which still are on znode's lock
+   request queue, this is done by reiser4_invalidate_lock(). Another
+   JNODE_IS_DYING znode status bit is used to invalidate pending lock requests.
+   Once it set all requesters are forced to return -EINVAL from
+   longterm_lock_znode(). Future locking attempts are not possible because all
+   ways to get references to that znode are removed already. Last, node is
+   uncaptured from transaction.
+
+   When last reference to the dying znode is just about to be released,
+   block number for this lock is released and znode is removed from the
+   hash table.
+
+   Now znode can be recycled.
+
+   [it's possible to free bitmap block and remove znode from the hash
+   table when last lock is released. This will result in having
+   referenced but completely orphaned znode]
+
+   6. Limbo
+
+   As have been mentioned above znodes with reference counter 0 are
+   still cached in a hash table. Once memory pressure increases they are
+   purged out of there [this requires something like LRU list for
+   efficient implementation. LRU list would also greatly simplify
+   implementation of coord cache that would in this case morph to just
+   scanning some initial segment of LRU list]. Data loaded into
+   unreferenced znode are flushed back to the durable storage if
+   necessary and memory is freed. Znodes themselves can be recycled at
+   this point too.
+
+*/
+
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/plugin_header.h"
+#include "plugin/node/node.h"
+#include "plugin/plugin.h"
+#include "txnmgr.h"
+#include "jnode.h"
+#include "znode.h"
+#include "block_alloc.h"
+#include "tree.h"
+#include "tree_walk.h"
+#include "super.h"
+#include "reiser4.h"
+
+#include <linux/pagemap.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+
+static z_hash_table *get_htable(reiser4_tree *,
+                               const reiser4_block_nr * const blocknr);
+static z_hash_table *znode_get_htable(const znode *);
+static void zdrop(znode *);
+
+/* hash table support */
+
+/* compare two block numbers for equality. Used by hash-table macros */
+static inline int
+blknreq(const reiser4_block_nr * b1, const reiser4_block_nr * b2)
+{
+       assert("nikita-534", b1 != NULL);
+       assert("nikita-535", b2 != NULL);
+
+       return *b1 == *b2;
+}
+
+/* Hash znode by block number. Used by hash-table macros */
+/* Audited by: umka (2002.06.11) */
+static inline __u32
+blknrhashfn(z_hash_table * table, const reiser4_block_nr * b)
+{
+       assert("nikita-536", b != NULL);
+
+       return *b & (REISER4_ZNODE_HASH_TABLE_SIZE - 1);
+}
+
+/* The hash table definition */
+#define KMALLOC(size) kmalloc((size), reiser4_ctx_gfp_mask_get())
+#define KFREE(ptr, size) kfree(ptr)
+TYPE_SAFE_HASH_DEFINE(z, znode, reiser4_block_nr, zjnode.key.z, zjnode.link.z,
+                     blknrhashfn, blknreq);
+#undef KFREE
+#undef KMALLOC
+
+/* slab for znodes */
+static struct kmem_cache *znode_cache;
+
+int znode_shift_order;
+
+/**
+ * init_znodes - create znode cache
+ *
+ * Initializes slab cache of znodes. It is part of reiser4 module initialization.
+ */
+int init_znodes(void)
+{
+       znode_cache = kmem_cache_create("znode", sizeof(znode), 0,
+                                       SLAB_HWCACHE_ALIGN |
+                                       SLAB_RECLAIM_ACCOUNT, NULL, NULL);
+       if (znode_cache == NULL)
+               return RETERR(-ENOMEM);
+
+       for (znode_shift_order = 0; (1 << znode_shift_order) < sizeof(znode);
+            ++znode_shift_order);
+       --znode_shift_order;
+       return 0;
+}
+
+/**
+ * done_znodes - delete znode cache
+ *
+ * This is called on reiser4 module unloading or system shutdown.
+ */
+void done_znodes(void)
+{
+       destroy_reiser4_cache(&znode_cache);
+}
+
+/* call this to initialise tree of znodes */
+int znodes_tree_init(reiser4_tree * tree /* tree to initialise znodes for */ )
+{
+       int result;
+       assert("umka-050", tree != NULL);
+
+       rwlock_init(&tree->dk_lock);
+
+       result = z_hash_init(&tree->zhash_table, REISER4_ZNODE_HASH_TABLE_SIZE);
+       if (result != 0)
+               return result;
+       result = z_hash_init(&tree->zfake_table, REISER4_ZNODE_HASH_TABLE_SIZE);
+       return result;
+}
+
+/* free this znode */
+void zfree(znode * node /* znode to free */ )
+{
+       assert("nikita-465", node != NULL);
+       assert("nikita-2120", znode_page(node) == NULL);
+       assert("nikita-2301", list_empty_careful(&node->lock.owners));
+       assert("nikita-2302", list_empty_careful(&node->lock.requestors));
+       assert("nikita-2663", (list_empty_careful(&ZJNODE(node)->capture_link) &&
+                              NODE_LIST(ZJNODE(node)) == NOT_CAPTURED));
+       assert("nikita-3220", list_empty(&ZJNODE(node)->jnodes));
+       assert("nikita-3293", !znode_is_right_connected(node));
+       assert("nikita-3294", !znode_is_left_connected(node));
+       assert("nikita-3295", node->left == NULL);
+       assert("nikita-3296", node->right == NULL);
+
+       /* not yet phash_jnode_destroy(ZJNODE(node)); */
+
+       kmem_cache_free(znode_cache, node);
+}
+
+/* call this to free tree of znodes */
+void znodes_tree_done(reiser4_tree * tree /* tree to finish with znodes of */ )
+{
+       znode *node;
+       znode *next;
+       z_hash_table *ztable;
+
+       /* scan znode hash-tables and kill all znodes, then free hash tables
+        * themselves. */
+
+       assert("nikita-795", tree != NULL);
+
+       ztable = &tree->zhash_table;
+
+       if (ztable->_table != NULL) {
+               for_all_in_htable(ztable, z, node, next) {
+                       node->c_count = 0;
+                       node->in_parent.node = NULL;
+                       assert("nikita-2179", atomic_read(&ZJNODE(node)->x_count) == 0);
+                       zdrop(node);
+               }
+
+               z_hash_done(&tree->zhash_table);
+       }
+
+       ztable = &tree->zfake_table;
+
+       if (ztable->_table != NULL) {
+               for_all_in_htable(ztable, z, node, next) {
+                       node->c_count = 0;
+                       node->in_parent.node = NULL;
+                       assert("nikita-2179", atomic_read(&ZJNODE(node)->x_count) == 0);
+                       zdrop(node);
+               }
+
+               z_hash_done(&tree->zfake_table);
+       }
+}
+
+/* ZNODE STRUCTURES */
+
+/* allocate fresh znode */
+znode *zalloc(gfp_t gfp_flag /* allocation flag */ )
+{
+       znode *node;
+
+       node = kmem_cache_alloc(znode_cache, gfp_flag);
+       return node;
+}
+
+/* Initialize fields of znode
+   @node:    znode to initialize;
+   @parent:  parent znode;
+   @tree:    tree we are in. */
+void zinit(znode * node, const znode * parent, reiser4_tree * tree)
+{
+       assert("nikita-466", node != NULL);
+       assert("umka-268", current_tree != NULL);
+
+       memset(node, 0, sizeof *node);
+
+       assert("umka-051", tree != NULL);
+
+       jnode_init(&node->zjnode, tree, JNODE_FORMATTED_BLOCK);
+       reiser4_init_lock(&node->lock);
+       init_parent_coord(&node->in_parent, parent);
+}
+
+/*
+ * remove znode from indices. This is called jput() when last reference on
+ * znode is released.
+ */
+void znode_remove(znode * node /* znode to remove */ , reiser4_tree * tree)
+{
+       assert("nikita-2108", node != NULL);
+       assert("nikita-470", node->c_count == 0);
+       assert_rw_write_locked(&(tree->tree_lock));
+
+       /* remove reference to this znode from cbk cache */
+       cbk_cache_invalidate(node, tree);
+
+       /* update c_count of parent */
+       if (znode_parent(node) != NULL) {
+               assert("nikita-472", znode_parent(node)->c_count > 0);
+               /* father, onto your hands I forward my spirit... */
+               znode_parent(node)->c_count--;
+               node->in_parent.node = NULL;
+       } else {
+               /* orphaned znode?! Root? */
+       }
+
+       /* remove znode from hash-table */
+       z_hash_remove_rcu(znode_get_htable(node), node);
+}
+
+/* zdrop() -- Remove znode from the tree.
+
+   This is called when znode is removed from the memory. */
+static void zdrop(znode * node /* znode to finish with */ )
+{
+       jdrop(ZJNODE(node));
+}
+
+/*
+ * put znode into right place in the hash table. This is called by relocate
+ * code.
+ */
+int znode_rehash(znode * node /* node to rehash */ ,
+                const reiser4_block_nr * new_block_nr /* new block number */ )
+{
+       z_hash_table *oldtable;
+       z_hash_table *newtable;
+       reiser4_tree *tree;
+
+       assert("nikita-2018", node != NULL);
+
+       tree = znode_get_tree(node);
+       oldtable = znode_get_htable(node);
+       newtable = get_htable(tree, new_block_nr);
+
+       write_lock_tree(tree);
+       /* remove znode from hash-table */
+       z_hash_remove_rcu(oldtable, node);
+
+       /* assertion no longer valid due to RCU */
+       /* assert("nikita-2019", z_hash_find(newtable, new_block_nr) == NULL); */
+
+       /* update blocknr */
+       znode_set_block(node, new_block_nr);
+       node->zjnode.key.z = *new_block_nr;
+
+       /* insert it into hash */
+       z_hash_insert_rcu(newtable, node);
+       write_unlock_tree(tree);
+       return 0;
+}
+
+/* ZNODE LOOKUP, GET, PUT */
+
+/* zlook() - get znode with given block_nr in a hash table or return NULL
+
+   If result is non-NULL then the znode's x_count is incremented.  Internal version
+   accepts pre-computed hash index.  The hash table is accessed under caller's
+   tree->hash_lock.
+*/
+znode *zlook(reiser4_tree * tree, const reiser4_block_nr * const blocknr)
+{
+       znode *result;
+       __u32 hash;
+       z_hash_table *htable;
+
+       assert("jmacd-506", tree != NULL);
+       assert("jmacd-507", blocknr != NULL);
+
+       htable = get_htable(tree, blocknr);
+       hash = blknrhashfn(htable, blocknr);
+
+       rcu_read_lock();
+       result = z_hash_find_index(htable, hash, blocknr);
+
+       if (result != NULL) {
+               add_x_ref(ZJNODE(result));
+               result = znode_rip_check(tree, result);
+       }
+       rcu_read_unlock();
+
+       return result;
+}
+
+/* return hash table where znode with block @blocknr is (or should be)
+ * stored */
+static z_hash_table *get_htable(reiser4_tree * tree,
+                               const reiser4_block_nr * const blocknr)
+{
+       z_hash_table *table;
+       if (is_disk_addr_unallocated(blocknr))
+               table = &tree->zfake_table;
+       else
+               table = &tree->zhash_table;
+       return table;
+}
+
+/* return hash table where znode @node is (or should be) stored */
+static z_hash_table *znode_get_htable(const znode * node)
+{
+       return get_htable(znode_get_tree(node), znode_get_block(node));
+}
+
+/* zget() - get znode from hash table, allocating it if necessary.
+
+   First a call to zlook, locating a x-referenced znode if one
+   exists.  If znode is not found, allocate new one and return.  Result
+   is returned with x_count reference increased.
+
+   LOCKS TAKEN:   TREE_LOCK, ZNODE_LOCK
+   LOCK ORDERING: NONE
+*/
+znode *zget(reiser4_tree * tree,
+           const reiser4_block_nr * const blocknr,
+           znode * parent, tree_level level, gfp_t gfp_flag)
+{
+       znode *result;
+       __u32 hashi;
+
+       z_hash_table *zth;
+
+       assert("jmacd-512", tree != NULL);
+       assert("jmacd-513", blocknr != NULL);
+       assert("jmacd-514", level < REISER4_MAX_ZTREE_HEIGHT);
+
+       zth = get_htable(tree, blocknr);
+       hashi = blknrhashfn(zth, blocknr);
+
+       /* NOTE-NIKITA address-as-unallocated-blocknr still is not
+          implemented. */
+
+       z_hash_prefetch_bucket(zth, hashi);
+
+       rcu_read_lock();
+       /* Find a matching BLOCKNR in the hash table.  If the znode is found,
+          we obtain an reference (x_count) but the znode remains unlocked.
+          Have to worry about race conditions later. */
+       result = z_hash_find_index(zth, hashi, blocknr);
+       /* According to the current design, the hash table lock protects new
+          znode references. */
+       if (result != NULL) {
+               add_x_ref(ZJNODE(result));
+               /* NOTE-NIKITA it should be so, but special case during
+                  creation of new root makes such assertion highly
+                  complicated.  */
+               assert("nikita-2131", 1 || znode_parent(result) == parent ||
+                      (ZF_ISSET(result, JNODE_ORPHAN)
+                       && (znode_parent(result) == NULL)));
+               result = znode_rip_check(tree, result);
+       }
+
+       rcu_read_unlock();
+
+       if (!result) {
+               znode *shadow;
+
+               result = zalloc(gfp_flag);
+               if (!result) {
+                       return ERR_PTR(RETERR(-ENOMEM));
+               }
+
+               zinit(result, parent, tree);
+               ZJNODE(result)->blocknr = *blocknr;
+               ZJNODE(result)->key.z = *blocknr;
+               result->level = level;
+
+               write_lock_tree(tree);
+
+               shadow = z_hash_find_index(zth, hashi, blocknr);
+               if (unlikely(shadow != NULL && !ZF_ISSET(shadow, JNODE_RIP))) {
+                       jnode_list_remove(ZJNODE(result));
+                       zfree(result);
+                       result = shadow;
+               } else {
+                       result->version = znode_build_version(tree);
+                       z_hash_insert_index_rcu(zth, hashi, result);
+
+                       if (parent != NULL)
+                               ++parent->c_count;
+               }
+
+               add_x_ref(ZJNODE(result));
+
+               write_unlock_tree(tree);
+       }
+#if REISER4_DEBUG
+       if (!reiser4_blocknr_is_fake(blocknr) && *blocknr != 0)
+               reiser4_check_block(blocknr, 1);
+#endif
+       /* Check for invalid tree level, return -EIO */
+       if (unlikely(znode_get_level(result) != level)) {
+               warning("jmacd-504",
+                       "Wrong level for cached block %llu: %i expecting %i",
+                       (unsigned long long)(*blocknr), znode_get_level(result),
+                       level);
+               zput(result);
+               return ERR_PTR(RETERR(-EIO));
+       }
+
+       assert("nikita-1227", znode_invariant(result));
+
+       return result;
+}
+
+/* ZNODE PLUGINS/DATA */
+
+/* "guess" plugin for node loaded from the disk. Plugin id of node plugin is
+   stored at the fixed offset from the beginning of the node. */
+static node_plugin *znode_guess_plugin(const znode * node      /* znode to guess
+                                                                * plugin of */ )
+{
+       reiser4_tree *tree;
+
+       assert("nikita-1053", node != NULL);
+       assert("nikita-1055", zdata(node) != NULL);
+
+       tree = znode_get_tree(node);
+       assert("umka-053", tree != NULL);
+
+       if (reiser4_is_set(tree->super, REISER4_ONE_NODE_PLUGIN)) {
+               return tree->nplug;
+       } else {
+               return node_plugin_by_disk_id
+                   (tree, &((common_node_header *) zdata(node))->plugin_id);
+#ifdef GUESS_EXISTS
+               reiser4_plugin *plugin;
+
+               /* NOTE-NIKITA add locking here when dynamic plugins will be
+                * implemented */
+               for_all_plugins(REISER4_NODE_PLUGIN_TYPE, plugin) {
+                       if ((plugin->u.node.guess != NULL)
+                           && plugin->u.node.guess(node))
+                               return plugin;
+               }
+               warning("nikita-1057", "Cannot guess node plugin");
+               print_znode("node", node);
+               return NULL;
+#endif
+       }
+}
+
+/* parse node header and install ->node_plugin */
+int zparse(znode * node /* znode to parse */ )
+{
+       int result;
+
+       assert("nikita-1233", node != NULL);
+       assert("nikita-2370", zdata(node) != NULL);
+
+       if (node->nplug == NULL) {
+               node_plugin *nplug;
+
+               nplug = znode_guess_plugin(node);
+               if (likely(nplug != NULL)) {
+                       result = nplug->parse(node);
+                       if (likely(result == 0))
+                               node->nplug = nplug;
+               } else {
+                       result = RETERR(-EIO);
+               }
+       } else
+               result = 0;
+       return result;
+}
+
+/* zload with readahead */
+int zload_ra(znode * node /* znode to load */ , ra_info_t * info)
+{
+       int result;
+
+       assert("nikita-484", node != NULL);
+       assert("nikita-1377", znode_invariant(node));
+       assert("jmacd-7771", !znode_above_root(node));
+       assert("nikita-2125", atomic_read(&ZJNODE(node)->x_count) > 0);
+       assert("nikita-3016", reiser4_schedulable());
+
+       if (info)
+               formatted_readahead(node, info);
+
+       result = jload(ZJNODE(node));
+       assert("nikita-1378", znode_invariant(node));
+       return result;
+}
+
+/* load content of node into memory */
+int zload(znode * node)
+{
+       return zload_ra(node, NULL);
+}
+
+/* call node plugin to initialise newly allocated node. */
+int zinit_new(znode * node /* znode to initialise */ , gfp_t gfp_flags)
+{
+       return jinit_new(ZJNODE(node), gfp_flags);
+}
+
+/* drop reference to node data. When last reference is dropped, data are
+   unloaded. */
+void zrelse(znode * node /* znode to release references to */ )
+{
+       assert("nikita-1381", znode_invariant(node));
+
+       jrelse(ZJNODE(node));
+}
+
+/* returns free space in node */
+unsigned znode_free_space(znode * node /* znode to query */ )
+{
+       assert("nikita-852", node != NULL);
+       return node_plugin_by_node(node)->free_space(node);
+}
+
+/* left delimiting key of znode */
+reiser4_key *znode_get_rd_key(znode * node /* znode to query */ )
+{
+       assert("nikita-958", node != NULL);
+       assert_rw_locked(&(znode_get_tree(node)->dk_lock));
+       assert("nikita-3067", LOCK_CNT_GTZ(rw_locked_dk));
+       assert("nikita-30671", node->rd_key_version != 0);
+       return &node->rd_key;
+}
+
+/* right delimiting key of znode */
+reiser4_key *znode_get_ld_key(znode * node /* znode to query */ )
+{
+       assert("nikita-974", node != NULL);
+       assert_rw_locked(&(znode_get_tree(node)->dk_lock));
+       assert("nikita-3068", LOCK_CNT_GTZ(rw_locked_dk));
+       assert("nikita-30681", node->ld_key_version != 0);
+       return &node->ld_key;
+}
+
+ON_DEBUG(atomic_t delim_key_version = ATOMIC_INIT(0);
+    )
+
+/* update right-delimiting key of @node */
+reiser4_key *znode_set_rd_key(znode * node, const reiser4_key * key)
+{
+       assert("nikita-2937", node != NULL);
+       assert("nikita-2939", key != NULL);
+       assert_rw_write_locked(&(znode_get_tree(node)->dk_lock));
+       assert("nikita-3069", LOCK_CNT_GTZ(write_locked_dk));
+       assert("nikita-2944",
+              znode_is_any_locked(node) ||
+              znode_get_level(node) != LEAF_LEVEL ||
+              keyge(key, &node->rd_key) ||
+              keyeq(&node->rd_key, reiser4_min_key()) ||
+              ZF_ISSET(node, JNODE_HEARD_BANSHEE));
+
+       node->rd_key = *key;
+       ON_DEBUG(node->rd_key_version = atomic_inc_return(&delim_key_version));
+       return &node->rd_key;
+}
+
+/* update left-delimiting key of @node */
+reiser4_key *znode_set_ld_key(znode * node, const reiser4_key * key)
+{
+       assert("nikita-2940", node != NULL);
+       assert("nikita-2941", key != NULL);
+       assert_rw_write_locked(&(znode_get_tree(node)->dk_lock));
+       assert("nikita-3070", LOCK_CNT_GTZ(write_locked_dk));
+       assert("nikita-2943",
+              znode_is_any_locked(node) || keyeq(&node->ld_key,
+                                                 reiser4_min_key()));
+
+       node->ld_key = *key;
+       ON_DEBUG(node->ld_key_version = atomic_inc_return(&delim_key_version));
+       return &node->ld_key;
+}
+
+/* true if @key is inside key range for @node */
+int znode_contains_key(znode * node /* znode to look in */ ,
+                      const reiser4_key * key /* key to look for */ )
+{
+       assert("nikita-1237", node != NULL);
+       assert("nikita-1238", key != NULL);
+
+       /* left_delimiting_key <= key <= right_delimiting_key */
+       return keyle(znode_get_ld_key(node), key)
+           && keyle(key, znode_get_rd_key(node));
+}
+
+/* same as znode_contains_key(), but lock dk lock */
+int znode_contains_key_lock(znode * node /* znode to look in */ ,
+                           const reiser4_key * key /* key to look for */ )
+{
+       int result;
+
+       assert("umka-056", node != NULL);
+       assert("umka-057", key != NULL);
+
+       read_lock_dk(znode_get_tree(node));
+       result = znode_contains_key(node, key);
+       read_unlock_dk(znode_get_tree(node));
+       return result;
+}
+
+/* get parent pointer, assuming tree is not locked */
+znode *znode_parent_nolock(const znode * node /* child znode */ )
+{
+       assert("nikita-1444", node != NULL);
+       return node->in_parent.node;
+}
+
+/* get parent pointer of znode */
+znode *znode_parent(const znode * node /* child znode */ )
+{
+       assert("nikita-1226", node != NULL);
+       assert("nikita-1406", LOCK_CNT_GTZ(rw_locked_tree));
+       return znode_parent_nolock(node);
+}
+
+/* detect uber znode used to protect in-superblock tree root pointer */
+int znode_above_root(const znode * node /* znode to query */ )
+{
+       assert("umka-059", node != NULL);
+
+       return disk_addr_eq(&ZJNODE(node)->blocknr, &UBER_TREE_ADDR);
+}
+
+/* check that @node is root---that its block number is recorder in the tree as
+   that of root node */
+#if REISER4_DEBUG
+static int znode_is_true_root(const znode * node /* znode to query */ )
+{
+       assert("umka-060", node != NULL);
+       assert("umka-061", current_tree != NULL);
+
+       return disk_addr_eq(znode_get_block(node),
+                           &znode_get_tree(node)->root_block);
+}
+#endif
+
+/* check that @node is root */
+int znode_is_root(const znode * node /* znode to query */ )
+{
+       assert("nikita-1206", node != NULL);
+
+       return znode_get_level(node) == znode_get_tree(node)->height;
+}
+
+/* Returns true is @node was just created by zget() and wasn't ever loaded
+   into memory. */
+/* NIKITA-HANS: yes */
+int znode_just_created(const znode * node)
+{
+       assert("nikita-2188", node != NULL);
+       return (znode_page(node) == NULL);
+}
+
+/* obtain updated ->znode_epoch. See seal.c for description. */
+__u64 znode_build_version(reiser4_tree * tree)
+{
+       __u64 result;
+
+       spin_lock(&tree->epoch_lock);
+       result = ++tree->znode_epoch;
+       spin_unlock(&tree->epoch_lock);
+       return result;
+}
+
+void init_load_count(load_count * dh)
+{
+       assert("nikita-2105", dh != NULL);
+       memset(dh, 0, sizeof *dh);
+}
+
+void done_load_count(load_count * dh)
+{
+       assert("nikita-2106", dh != NULL);
+       if (dh->node != NULL) {
+               for (; dh->d_ref > 0; --dh->d_ref)
+                       zrelse(dh->node);
+               dh->node = NULL;
+       }
+}
+
+static int incr_load_count(load_count * dh)
+{
+       int result;
+
+       assert("nikita-2110", dh != NULL);
+       assert("nikita-2111", dh->node != NULL);
+
+       result = zload(dh->node);
+       if (result == 0)
+               ++dh->d_ref;
+       return result;
+}
+
+int incr_load_count_znode(load_count * dh, znode * node)
+{
+       assert("nikita-2107", dh != NULL);
+       assert("nikita-2158", node != NULL);
+       assert("nikita-2109",
+              ergo(dh->node != NULL, (dh->node == node) || (dh->d_ref == 0)));
+
+       dh->node = node;
+       return incr_load_count(dh);
+}
+
+int incr_load_count_jnode(load_count * dh, jnode * node)
+{
+       if (jnode_is_znode(node)) {
+               return incr_load_count_znode(dh, JZNODE(node));
+       }
+       return 0;
+}
+
+void copy_load_count(load_count * new, load_count * old)
+{
+       int ret = 0;
+       done_load_count(new);
+       new->node = old->node;
+       new->d_ref = 0;
+
+       while ((new->d_ref < old->d_ref) && (ret = incr_load_count(new)) == 0) {
+       }
+
+       assert("jmacd-87589", ret == 0);
+}
+
+void move_load_count(load_count * new, load_count * old)
+{
+       done_load_count(new);
+       new->node = old->node;
+       new->d_ref = old->d_ref;
+       old->node = NULL;
+       old->d_ref = 0;
+}
+
+/* convert parent pointer into coord */
+void parent_coord_to_coord(const parent_coord_t * pcoord, coord_t * coord)
+{
+       assert("nikita-3204", pcoord != NULL);
+       assert("nikita-3205", coord != NULL);
+
+       coord_init_first_unit_nocheck(coord, pcoord->node);
+       coord_set_item_pos(coord, pcoord->item_pos);
+       coord->between = AT_UNIT;
+}
+
+/* pack coord into parent_coord_t */
+void coord_to_parent_coord(const coord_t * coord, parent_coord_t * pcoord)
+{
+       assert("nikita-3206", pcoord != NULL);
+       assert("nikita-3207", coord != NULL);
+
+       pcoord->node = coord->node;
+       pcoord->item_pos = coord->item_pos;
+}
+
+/* Initialize a parent hint pointer. (parent hint pointer is a field in znode,
+   look for comments there) */
+void init_parent_coord(parent_coord_t * pcoord, const znode * node)
+{
+       pcoord->node = (znode *) node;
+       pcoord->item_pos = (unsigned short)~0;
+}
+
+#if REISER4_DEBUG
+
+/* debugging aid: znode invariant */
+static int znode_invariant_f(const znode * node /* znode to check */ ,
+                            char const **msg   /* where to store error
+                                                * message, if any */ )
+{
+#define _ergo(ant, con)                                                \
+       ((*msg) = "{" #ant "} ergo {" #con "}", ergo((ant), (con)))
+
+#define _equi(e1, e2)                                          \
+       ((*msg) = "{" #e1 "} <=> {" #e2 "}", equi((e1), (e2)))
+
+#define _check(exp) ((*msg) = #exp, (exp))
+
+       return jnode_invariant_f(ZJNODE(node), msg) &&
+           /* [znode-fake] invariant */
+           /* fake znode doesn't have a parent, and */
+           _ergo(znode_get_level(node) == 0, znode_parent(node) == NULL) &&
+           /* there is another way to express this very check, and */
+           _ergo(znode_above_root(node), znode_parent(node) == NULL) &&
+           /* it has special block number, and */
+           _ergo(znode_get_level(node) == 0,
+                 disk_addr_eq(znode_get_block(node), &UBER_TREE_ADDR)) &&
+           /* it is the only znode with such block number, and */
+           _ergo(!znode_above_root(node) && znode_is_loaded(node),
+                 !disk_addr_eq(znode_get_block(node), &UBER_TREE_ADDR)) &&
+           /* it is parent of the tree root node */
+           _ergo(znode_is_true_root(node),
+                 znode_above_root(znode_parent(node))) &&
+           /* [znode-level] invariant */
+           /* level of parent znode is one larger than that of child,
+              except for the fake znode, and */
+           _ergo(znode_parent(node) && !znode_above_root(znode_parent(node)),
+                 znode_get_level(znode_parent(node)) ==
+                 znode_get_level(node) + 1) &&
+           /* left neighbor is at the same level, and */
+           _ergo(znode_is_left_connected(node) && node->left != NULL,
+                 znode_get_level(node) == znode_get_level(node->left)) &&
+           /* right neighbor is at the same level */
+           _ergo(znode_is_right_connected(node) && node->right != NULL,
+                 znode_get_level(node) == znode_get_level(node->right)) &&
+           /* [znode-connected] invariant */
+           _ergo(node->left != NULL, znode_is_left_connected(node)) &&
+           _ergo(node->right != NULL, znode_is_right_connected(node)) &&
+           _ergo(!znode_is_root(node) && node->left != NULL,
+                 znode_is_right_connected(node->left) &&
+                 node->left->right == node) &&
+           _ergo(!znode_is_root(node) && node->right != NULL,
+                 znode_is_left_connected(node->right) &&
+                 node->right->left == node) &&
+           /* [znode-c_count] invariant */
+           /* for any znode, c_count of its parent is greater than 0 */
+           _ergo(znode_parent(node) != NULL &&
+                 !znode_above_root(znode_parent(node)),
+                 znode_parent(node)->c_count > 0) &&
+           /* leaves don't have children */
+           _ergo(znode_get_level(node) == LEAF_LEVEL,
+                 node->c_count == 0) &&
+           _check(node->zjnode.jnodes.prev != NULL) &&
+           _check(node->zjnode.jnodes.next != NULL) &&
+           /* orphan doesn't have a parent */
+           _ergo(ZF_ISSET(node, JNODE_ORPHAN), znode_parent(node) == 0) &&
+           /* [znode-modify] invariant */
+           /* if znode is not write-locked, its checksum remains
+            * invariant */
+           /* unfortunately, zlock is unordered w.r.t. jnode_lock, so we
+            * cannot check this. */
+           /* [znode-refs] invariant */
+           /* only referenced znode can be long-term locked */
+           _ergo(znode_is_locked(node),
+                 atomic_read(&ZJNODE(node)->x_count) != 0);
+}
+
+/* debugging aid: check znode invariant and panic if it doesn't hold */
+int znode_invariant(znode * node /* znode to check */ )
+{
+       char const *failed_msg;
+       int result;
+
+       assert("umka-063", node != NULL);
+       assert("umka-064", current_tree != NULL);
+
+       spin_lock_znode(node);
+       read_lock_tree(znode_get_tree(node));
+       result = znode_invariant_f(node, &failed_msg);
+       if (!result) {
+               /* print_znode("corrupted node", node); */
+               warning("jmacd-555", "Condition %s failed", failed_msg);
+       }
+       read_unlock_tree(znode_get_tree(node));
+       spin_unlock_znode(node);
+       return result;
+}
+
+/* return non-0 iff data are loaded into znode */
+int znode_is_loaded(const znode * node /* znode to query */ )
+{
+       assert("nikita-497", node != NULL);
+       return jnode_is_loaded(ZJNODE(node));
+}
+
+unsigned long znode_times_locked(const znode * z)
+{
+       return z->times_locked;
+}
+
+#endif                         /* REISER4_DEBUG */
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/fs/reiser4/znode.h linux-2.6.20/fs/reiser4/znode.h
--- linux-2.6.20.orig/fs/reiser4/znode.h        1970-01-01 03:00:00.000000000 +0300
+++ linux-2.6.20/fs/reiser4/znode.h     2007-05-06 14:50:43.907040716 +0400
@@ -0,0 +1,434 @@
+/* Copyright 2001, 2002, 2003, 2004 by Hans Reiser, licensing governed by
+ * reiser4/README */
+
+/* Declaration of znode (Zam's node). See znode.c for more details. */
+
+#ifndef __ZNODE_H__
+#define __ZNODE_H__
+
+#include "forward.h"
+#include "debug.h"
+#include "dformat.h"
+#include "key.h"
+#include "coord.h"
+#include "plugin/node/node.h"
+#include "jnode.h"
+#include "lock.h"
+#include "readahead.h"
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/pagemap.h>     /* for PAGE_CACHE_SIZE */
+#include <asm/atomic.h>
+#include <asm/semaphore.h>
+
+/* znode tracks its position within parent (internal item in a parent node,
+ * that contains znode's block number). */
+typedef struct parent_coord {
+       znode *node;
+       pos_in_node_t item_pos;
+} parent_coord_t;
+
+/* &znode - node in a reiser4 tree.
+
+   NOTE-NIKITA fields in this struct have to be rearranged (later) to reduce
+   cacheline pressure.
+
+   Locking:
+
+   Long term: data in a disk node attached to this znode are protected
+   by long term, deadlock aware lock ->lock;
+
+   Spin lock: the following fields are protected by the spin lock:
+
+    ->lock
+
+   Following fields are protected by the global tree lock:
+
+    ->left
+    ->right
+    ->in_parent
+    ->c_count
+
+   Following fields are protected by the global delimiting key lock (dk_lock):
+
+    ->ld_key (to update ->ld_key long-term lock on the node is also required)
+    ->rd_key
+
+   Following fields are protected by the long term lock:
+
+    ->nr_items
+
+   ->node_plugin is never changed once set. This means that after code made
+   itself sure that field is valid it can be accessed without any additional
+   locking.
+
+   ->level is immutable.
+
+   Invariants involving this data-type:
+
+      [znode-fake]
+      [znode-level]
+      [znode-connected]
+      [znode-c_count]
+      [znode-refs]
+      [jnode-refs]
+      [jnode-queued]
+      [znode-modify]
+
+    For this to be made into a clustering or NUMA filesystem, we would want to eliminate all of the global locks.
+    Suggestions for how to do that are desired.*/
+struct znode {
+       /* Embedded jnode. */
+       jnode zjnode;
+
+       /* contains three subfields, node, pos_in_node, and pos_in_unit.
+
+          pos_in_node and pos_in_unit are only hints that are cached to
+          speed up lookups during balancing. They are not required to be up to
+          date. Synched in find_child_ptr().
+
+          This value allows us to avoid expensive binary searches.
+
+          in_parent->node points to the parent of this node, and is NOT a
+          hint.
+        */
+       parent_coord_t in_parent;
+
+       /*
+        * sibling list pointers
+        */
+
+       /* left-neighbor */
+       znode *left;
+       /* right-neighbor */
+       znode *right;
+
+       /* long term lock on node content. This lock supports deadlock
+          detection. See lock.c
+        */
+       zlock lock;
+
+       /* You cannot remove from memory a node that has children in
+          memory. This is because we rely on the fact that parent of given
+          node can always be reached without blocking for io. When reading a
+          node into memory you must increase the c_count of its parent, when
+          removing it from memory you must decrease the c_count.  This makes
+          the code simpler, and the cases where it is suboptimal are truly
+          obscure.
+        */
+       int c_count;
+
+       /* plugin of node attached to this znode. NULL if znode is not
+          loaded. */
+       node_plugin *nplug;
+
+       /* version of znode data. This is increased on each modification. This
+        * is necessary to implement seals (see seal.[ch]) efficiently. */
+       __u64 version;
+
+       /* left delimiting key. Necessary to efficiently perform
+          balancing with node-level locking. Kept in memory only. */
+       reiser4_key ld_key;
+       /* right delimiting key. */
+       reiser4_key rd_key;
+
+       /* znode's tree level */
+       __u16 level;
+       /* number of items in this node. This field is modified by node
+        * plugin. */
+       __u16 nr_items;
+
+#if REISER4_DEBUG
+       void *creator;
+       reiser4_key first_key;
+       unsigned long times_locked;
+       int left_version;       /* when node->left was updated */
+       int right_version;      /* when node->right was updated */
+       int ld_key_version;     /* when node->ld_key was updated */
+       int rd_key_version;     /* when node->rd_key was updated */
+#endif
+
+} __attribute__ ((aligned(16)));
+
+ON_DEBUG(extern atomic_t delim_key_version;
+    )
+
+/* In general I think these macros should not be exposed. */
+#define znode_is_locked(node)          (lock_is_locked(&node->lock))
+#define znode_is_rlocked(node)         (lock_is_rlocked(&node->lock))
+#define znode_is_wlocked(node)         (lock_is_wlocked(&node->lock))
+#define znode_is_wlocked_once(node)    (lock_is_wlocked_once(&node->lock))
+#define znode_can_be_rlocked(node)     (lock_can_be_rlocked(&node->lock))
+#define is_lock_compatible(node, mode) (lock_mode_compatible(&node->lock, mode))
+/* Macros for accessing the znode state. */
+#define        ZF_CLR(p,f)             JF_CLR  (ZJNODE(p), (f))
+#define        ZF_ISSET(p,f)           JF_ISSET(ZJNODE(p), (f))
+#define        ZF_SET(p,f)             JF_SET  (ZJNODE(p), (f))
+extern znode *zget(reiser4_tree * tree, const reiser4_block_nr * const block,
+                  znode * parent, tree_level level, gfp_t gfp_flag);
+extern znode *zlook(reiser4_tree * tree, const reiser4_block_nr * const block);
+extern int zload(znode * node);
+extern int zload_ra(znode * node, ra_info_t * info);
+extern int zinit_new(znode * node, gfp_t gfp_flags);
+extern void zrelse(znode * node);
+extern void znode_change_parent(znode * new_parent, reiser4_block_nr * block);
+
+/* size of data in znode */
+static inline unsigned
+znode_size(const znode * node UNUSED_ARG /* znode to query */ )
+{
+       assert("nikita-1416", node != NULL);
+       return PAGE_CACHE_SIZE;
+}
+
+extern void parent_coord_to_coord(const parent_coord_t * pcoord,
+                                 coord_t * coord);
+extern void coord_to_parent_coord(const coord_t * coord,
+                                 parent_coord_t * pcoord);
+extern void init_parent_coord(parent_coord_t * pcoord, const znode * node);
+
+extern unsigned znode_free_space(znode * node);
+
+extern reiser4_key *znode_get_rd_key(znode * node);
+extern reiser4_key *znode_get_ld_key(znode * node);
+
+extern reiser4_key *znode_set_rd_key(znode * node, const reiser4_key * key);
+extern reiser4_key *znode_set_ld_key(znode * node, const reiser4_key * key);
+
+/* `connected' state checks */
+static inline int znode_is_right_connected(const znode * node)
+{
+       return ZF_ISSET(node, JNODE_RIGHT_CONNECTED);
+}
+
+static inline int znode_is_left_connected(const znode * node)
+{
+       return ZF_ISSET(node, JNODE_LEFT_CONNECTED);
+}
+
+static inline int znode_is_connected(const znode * node)
+{
+       return znode_is_right_connected(node) && znode_is_left_connected(node);
+}
+
+extern int znode_shift_order;
+extern int znode_rehash(znode * node, const reiser4_block_nr * new_block_nr);
+extern void znode_remove(znode *, reiser4_tree *);
+extern znode *znode_parent(const znode * node);
+extern znode *znode_parent_nolock(const znode * node);
+extern int znode_above_root(const znode * node);
+extern int init_znodes(void);
+extern void done_znodes(void);
+extern int znodes_tree_init(reiser4_tree * ztree);
+extern void znodes_tree_done(reiser4_tree * ztree);
+extern int znode_contains_key(znode * node, const reiser4_key * key);
+extern int znode_contains_key_lock(znode * node, const reiser4_key * key);
+extern unsigned znode_save_free_space(znode * node);
+extern unsigned znode_recover_free_space(znode * node);
+extern znode *zalloc(gfp_t gfp_flag);
+extern void zinit(znode *, const znode * parent, reiser4_tree *);
+extern int zparse(znode * node);
+
+extern int znode_just_created(const znode * node);
+
+extern void zfree(znode * node);
+
+#if REISER4_DEBUG
+extern void print_znode(const char *prefix, const znode * node);
+#else
+#define print_znode( p, n ) noop
+#endif
+
+/* Make it look like various znode functions exist instead of treating znodes as
+   jnodes in znode-specific code. */
+#define znode_page(x)               jnode_page ( ZJNODE(x) )
+#define zdata(x)                    jdata ( ZJNODE(x) )
+#define znode_get_block(x)          jnode_get_block ( ZJNODE(x) )
+#define znode_created(x)            jnode_created ( ZJNODE(x) )
+#define znode_set_created(x)        jnode_set_created ( ZJNODE(x) )
+#define znode_convertible(x)        jnode_convertible (ZJNODE(x))
+#define znode_set_convertible(x)    jnode_set_convertible (ZJNODE(x))
+
+#define znode_is_dirty(x)           jnode_is_dirty    ( ZJNODE(x) )
+#define znode_check_dirty(x)        jnode_check_dirty ( ZJNODE(x) )
+#define znode_make_clean(x)         jnode_make_clean   ( ZJNODE(x) )
+#define znode_set_block(x, b)       jnode_set_block ( ZJNODE(x), (b) )
+
+#define spin_lock_znode(x)          spin_lock_jnode ( ZJNODE(x) )
+#define spin_unlock_znode(x)        spin_unlock_jnode ( ZJNODE(x) )
+#define spin_trylock_znode(x)       spin_trylock_jnode ( ZJNODE(x) )
+#define spin_znode_is_locked(x)     spin_jnode_is_locked ( ZJNODE(x) )
+#define spin_znode_is_not_locked(x) spin_jnode_is_not_locked ( ZJNODE(x) )
+
+#if REISER4_DEBUG
+extern int znode_x_count_is_protected(const znode * node);
+extern int znode_invariant(znode * node);
+#endif
+
+/* acquire reference to @node */
+static inline znode *zref(znode * node)
+{
+       /* change of x_count from 0 to 1 is protected by tree spin-lock */
+       return JZNODE(jref(ZJNODE(node)));
+}
+
+/* release reference to @node */
+static inline void zput(znode * node)
+{
+       assert("nikita-3564", znode_invariant(node));
+       jput(ZJNODE(node));
+}
+
+/* get the level field for a znode */
+static inline tree_level znode_get_level(const znode * node)
+{
+       return node->level;
+}
+
+/* get the level field for a jnode */
+static inline tree_level jnode_get_level(const jnode * node)
+{
+       if (jnode_is_znode(node))
+               return znode_get_level(JZNODE(node));
+       else
+               /* unformatted nodes are all at the LEAF_LEVEL and for
+                  "semi-formatted" nodes like bitmaps, level doesn't matter. */
+               return LEAF_LEVEL;
+}
+
+/* true if jnode is on leaf level */
+static inline int jnode_is_leaf(const jnode * node)
+{
+       if (jnode_is_znode(node))
+               return (znode_get_level(JZNODE(node)) == LEAF_LEVEL);
+       if (jnode_get_type(node) == JNODE_UNFORMATTED_BLOCK)
+               return 1;
+       return 0;
+}
+
+/* return znode's tree */
+static inline reiser4_tree *znode_get_tree(const znode * node)
+{
+       assert("nikita-2692", node != NULL);
+       return jnode_get_tree(ZJNODE(node));
+}
+
+/* resolve race with zput */
+static inline znode *znode_rip_check(reiser4_tree * tree, znode * node)
+{
+       jnode *j;
+
+       j = jnode_rip_sync(tree, ZJNODE(node));
+       if (likely(j != NULL))
+               node = JZNODE(j);
+       else
+               node = NULL;
+       return node;
+}
+
+#if defined(REISER4_DEBUG)
+int znode_is_loaded(const znode * node /* znode to query */ );
+#endif
+
+extern __u64 znode_build_version(reiser4_tree * tree);
+
+/* Data-handles.  A data handle object manages pairing calls to zload() and zrelse().  We
+   must load the data for a node in many places.  We could do this by simply calling
+   zload() everywhere, the difficulty arises when we must release the loaded data by
+   calling zrelse.  In a function with many possible error/return paths, it requires extra
+   work to figure out which exit paths must call zrelse and those which do not.  The data
+   handle automatically calls zrelse for every zload that it is responsible for.  In that
+   sense, it acts much like a lock_handle.
+*/
+typedef struct load_count {
+       znode *node;
+       int d_ref;
+} load_count;
+
+extern void init_load_count(load_count * lc);  /* Initialize a load_count set the current node to NULL. */
+extern void done_load_count(load_count * dh);  /* Finalize a load_count: call zrelse() if necessary */
+extern int incr_load_count_znode(load_count * dh, znode * node);       /* Set the argument znode to the current node, call zload(). */
+extern int incr_load_count_jnode(load_count * dh, jnode * node);       /* If the argument jnode is formatted, do the same as
+                                                                        * incr_load_count_znode, otherwise do nothing (unformatted nodes
+                                                                        * don't require zload/zrelse treatment). */
+extern void move_load_count(load_count * new, load_count * old);       /* Move the contents of a load_count.  Old handle is released. */
+extern void copy_load_count(load_count * new, load_count * old);       /* Copy the contents of a load_count.  Old handle remains held. */
+
+/* Variable initializers for load_count. */
+#define INIT_LOAD_COUNT ( load_count * ){ .node = NULL, .d_ref = 0 }
+#define INIT_LOAD_COUNT_NODE( n ) ( load_count ){ .node = ( n ), .d_ref = 0 }
+/* A convenience macro for use in assertions or debug-only code, where loaded
+   data is only required to perform the debugging check.  This macro
+   encapsulates an expression inside a pair of calls to zload()/zrelse(). */
+#define WITH_DATA( node, exp )                         \
+({                                                     \
+       long __with_dh_result;                          \
+       znode *__with_dh_node;                          \
+                                                       \
+       __with_dh_node = ( node );                      \
+       __with_dh_result = zload( __with_dh_node );     \
+       if( __with_dh_result == 0 ) {                   \
+               __with_dh_result = ( long )( exp );     \
+               zrelse( __with_dh_node );               \
+       }                                               \
+       __with_dh_result;                               \
+})
+
+/* Same as above, but accepts a return value in case zload fails. */
+#define WITH_DATA_RET( node, ret, exp )                        \
+({                                                     \
+       int __with_dh_result;                           \
+       znode *__with_dh_node;                          \
+                                                       \
+       __with_dh_node = ( node );                      \
+       __with_dh_result = zload( __with_dh_node );     \
+       if( __with_dh_result == 0 ) {                   \
+               __with_dh_result = ( int )( exp );      \
+               zrelse( __with_dh_node );               \
+       } else                                          \
+               __with_dh_result = ( ret );             \
+       __with_dh_result;                               \
+})
+
+#define WITH_COORD(coord, exp)                 \
+({                                             \
+       coord_t *__coord;                       \
+                                               \
+       __coord = (coord);                      \
+       coord_clear_iplug(__coord);             \
+       WITH_DATA(__coord->node, exp);          \
+})
+
+#if REISER4_DEBUG
+#define STORE_COUNTERS                                         \
+       reiser4_lock_counters_info __entry_counters =           \
+               *reiser4_lock_counters()
+#define CHECK_COUNTERS                                                 \
+ON_DEBUG_CONTEXT(                                                      \
+({                                                                     \
+       __entry_counters.x_refs = reiser4_lock_counters() -> x_refs;    \
+       __entry_counters.t_refs = reiser4_lock_counters() -> t_refs;    \
+       __entry_counters.d_refs = reiser4_lock_counters() -> d_refs;    \
+       assert("nikita-2159",                                           \
+              !memcmp(&__entry_counters, reiser4_lock_counters(),      \
+                      sizeof __entry_counters));                       \
+}) )
+
+#else
+#define STORE_COUNTERS
+#define CHECK_COUNTERS noop
+#endif
+
+/* __ZNODE_H__ */
+#endif
+
+/* Make Linus happy.
+   Local variables:
+   c-indentation-style: "K&R"
+   mode-name: "LC"
+   c-basic-offset: 8
+   tab-width: 8
+   fill-column: 120
+   End:
+*/
diff -urN linux-2.6.20.orig/include/linux/fs.h linux-2.6.20/include/linux/fs.h
--- linux-2.6.20.orig/include/linux/fs.h        2007-05-06 15:04:41.352625543 +0400
+++ linux-2.6.20/include/linux/fs.h     2007-05-06 14:50:43.911041966 +0400
@@ -1165,6 +1165,8 @@
        void (*clear_inode) (struct inode *);
        void (*umount_begin) (struct vfsmount *, int);
 
+       void (*sync_inodes) (struct super_block *sb,
+                               struct writeback_control *wbc);
        int (*show_options)(struct seq_file *, struct vfsmount *);
        int (*show_stats)(struct seq_file *, struct vfsmount *);
 #ifdef CONFIG_QUOTA
@@ -1583,6 +1585,7 @@
 extern int invalidate_inode_pages2_range(struct address_space *mapping,
                                         pgoff_t start, pgoff_t end);
 extern int write_inode_now(struct inode *, int);
+extern void generic_sync_sb_inodes(struct super_block *, struct writeback_control *);
 extern int filemap_fdatawrite(struct address_space *);
 extern int filemap_flush(struct address_space *);
 extern int filemap_fdatawait(struct address_space *);
diff -urN linux-2.6.20.orig/lib/radix-tree.c linux-2.6.20/lib/radix-tree.c
--- linux-2.6.20.orig/lib/radix-tree.c  2007-05-06 15:04:42.096858012 +0400
+++ linux-2.6.20/lib/radix-tree.c       2007-05-06 14:50:43.915043216 +0400
@@ -151,6 +151,7 @@
 out:
        return ret;
 }
+EXPORT_SYMBOL(radix_tree_preload);
 
 static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
                int offset)
diff -urN linux-2.6.20.orig/mm/filemap.c linux-2.6.20/mm/filemap.c
--- linux-2.6.20.orig/mm/filemap.c      2007-05-06 15:04:42.108861762 +0400
+++ linux-2.6.20/mm/filemap.c   2007-05-06 14:50:43.919044465 +0400
@@ -121,6 +121,7 @@
        mapping->nrpages--;
        __dec_zone_page_state(page, NR_FILE_PAGES);
 }
+EXPORT_SYMBOL(__remove_from_page_cache);
 
 void remove_from_page_cache(struct page *page)
 {
@@ -132,6 +133,7 @@
        __remove_from_page_cache(page);
        write_unlock_irq(&mapping->tree_lock);
 }
+EXPORT_SYMBOL(remove_from_page_cache);
 
 static int sync_page(void *word)
 {
@@ -738,6 +740,7 @@
        read_unlock_irq(&mapping->tree_lock);
        return ret;
 }
+EXPORT_SYMBOL(add_to_page_cache_lru);
 
 /**
  * find_get_pages_contig - gang contiguous pagecache lookup
@@ -798,6 +801,7 @@
        read_unlock_irq(&mapping->tree_lock);
        return ret;
 }
+EXPORT_SYMBOL(find_get_pages);
 
 /**
  * grab_cache_page_nowait - returns locked page at given index in given cache
@@ -855,6 +859,7 @@
 
        ra->ra_pages /= 4;
 }
+EXPORT_SYMBOL(find_get_pages_tag);
 
 /**
  * do_generic_mapping_read - generic file read routine
diff -urN linux-2.6.20.orig/mm/readahead.c linux-2.6.20/mm/readahead.c
--- linux-2.6.20.orig/mm/readahead.c    2007-05-06 15:04:42.144873010 +0400
+++ linux-2.6.20/mm/readahead.c 2007-05-06 14:50:43.919044465 +0400
@@ -568,6 +568,7 @@
        ra->flags &= ~RA_FLAG_INCACHE;
        ra->cache_hit = 0;
 }
+EXPORT_SYMBOL_GPL(handle_ra_miss);
 
 /*
  * Given a desired number of PAGE_CACHE_SIZE readahead pages, return a
Files linux-2.6.20.orig/scripts/kconfig/mconf and linux-2.6.20/scripts/kconfig/mconf differ