fs/reiserfs/file.c

   1 /*
   2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
   3  */
   4
   5 #include <linux/time.h>
   6 #include <linux/reiserfs_fs.h>
   7 #include <linux/reiserfs_acl.h>
   8 #include <linux/reiserfs_xattr.h>
   9 #include <asm/uaccess.h>
  10 #include <linux/pagemap.h>
  11 #include <linux/swap.h>
  12 #include <linux/writeback.h>
  13 #include <linux/blkdev.h>
  14 #include <linux/buffer_head.h>
  15 #include <linux/quotaops.h>
  16
  17 /*
  18 ** We pack the tails of files on file close, not at the time they are written.
  19 ** This implies an unnecessary copy of the tail and an unnecessary indirect item
  20 ** insertion/balancing, for files that are written in one write.
  21 ** It avoids unnecessary tail packings (balances) for files that are written in
  22 ** multiple writes and are small enough to have tails.
  23 **
  24 ** file_release is called by the VFS layer when the file is closed.  If
  25 ** this is the last open file descriptor, and the file
  26 ** small enough to have a tail, and the tail is currently in an
  27 ** unformatted node, the tail is converted back into a direct item.
  28 **
  29 ** We use reiserfs_truncate_file to pack the tail, since it already has
  30 ** all the conditions coded.
  31 */
  32 static int reiserfs_file_release(struct inode *inode, struct file *filp)
  33 {
  34
  35         struct reiserfs_transaction_handle th;
  36         int err;
  37         int jbegin_failure = 0;
  38
  39         BUG_ON(!S_ISREG(inode->i_mode));
  40
  41         /* fast out for when nothing needs to be done */
  42         if ((atomic_read(&inode->i_count) > 1 ||
  43              !(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||
  44              !tail_has_to_be_packed(inode)) &&
  45             REISERFS_I(inode)->i_prealloc_count <= 0) {
  46                 return 0;
  47         }
  48
  49         mutex_lock(&inode->i_mutex);
  50
  51         mutex_lock(&(REISERFS_I(inode)->i_mmap));
  52         if (REISERFS_I(inode)->i_flags & i_ever_mapped)
  53                 REISERFS_I(inode)->i_flags &= ~i_pack_on_close_mask;
  54
  55         reiserfs_write_lock(inode->i_sb);
  56         /* freeing preallocation only involves relogging blocks that
  57          * are already in the current transaction.  preallocation gets
  58          * freed at the end of each transaction, so it is impossible for
  59          * us to log any additional blocks (including quota blocks)
  60          */
  61         err = journal_begin(&th, inode->i_sb, 1);
  62         if (err) {
  63                 /* uh oh, we can't allow the inode to go away while there
  64                  * is still preallocation blocks pending.  Try to join the
  65                  * aborted transaction
  66                  */
  67                 jbegin_failure = err;
  68                 err = journal_join_abort(&th, inode->i_sb, 1);
  69
  70                 if (err) {
  71                         /* hmpf, our choices here aren't good.  We can pin the inode
  72                          * which will disallow unmount from every happening, we can
  73                          * do nothing, which will corrupt random memory on unmount,
  74                          * or we can forcibly remove the file from the preallocation
  75                          * list, which will leak blocks on disk.  Lets pin the inode
  76                          * and let the admin know what is going on.
  77                          */
  78                         igrab(inode);
  79                         reiserfs_warning(inode->i_sb, "clm-9001",
  80                                          "pinning inode %lu because the "
  81                                          "preallocation can't be freed",
  82                                          inode->i_ino);
  83                         goto out;
  84                 }
  85         }
  86         reiserfs_update_inode_transaction(inode);
  87
  88 #ifdef REISERFS_PREALLOCATE
  89         reiserfs_discard_prealloc(&th, inode);
  90 #endif
  91         err = journal_end(&th, inode->i_sb, 1);
  92
  93         /* copy back the error code from journal_begin */
  94         if (!err)
  95                 err = jbegin_failure;
  96
  97         if (!err && atomic_read(&inode->i_count) <= 1 &&
  98             (REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
  99             tail_has_to_be_packed(inode)) {
 100                 /* if regular file is released by last holder and it has been
 101                    appended (we append by unformatted node only) or its direct
 102                    item(s) had to be converted, then it may have to be
 103                    indirect2direct converted */
 104                 err = reiserfs_truncate_file(inode, 0);
 105         }
 106       out:
 107         mutex_unlock(&(REISERFS_I(inode)->i_mmap));
 108         mutex_unlock(&inode->i_mutex);
 109         reiserfs_write_unlock(inode->i_sb);
 110         return err;
 111 }
 112
 113 static int reiserfs_file_mmap(struct file *file, struct vm_area_struct *vma)
 114 {
 115         struct inode *inode;
 116
 117         inode = file->f_path.dentry->d_inode;
 118         mutex_lock(&(REISERFS_I(inode)->i_mmap));
 119         REISERFS_I(inode)->i_flags |= i_ever_mapped;
 120         mutex_unlock(&(REISERFS_I(inode)->i_mmap));
 121
 122         return generic_file_mmap(file, vma);
 123 }
 124
 125 static void reiserfs_vfs_truncate_file(struct inode *inode)
 126 {
 127         reiserfs_truncate_file(inode, 1);
 128 }
 129
 130 /* Sync a reiserfs file. */
 131
 132 /*
 133  * FIXME: sync_mapping_buffers() never has anything to sync.  Can
 134  * be removed...
 135  */
 136
 137 static int reiserfs_sync_file(struct file *filp,
 138                               struct dentry *dentry, int datasync)
 139 {
 140         struct inode *inode = dentry->d_inode;
 141         int err;
 142         int barrier_done;
 143
 144         BUG_ON(!S_ISREG(inode->i_mode));
 145         err = sync_mapping_buffers(inode->i_mapping);
 146         reiserfs_write_lock(inode->i_sb);
 147         barrier_done = reiserfs_commit_for_inode(inode);
 148         reiserfs_write_unlock(inode->i_sb);
 149         if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
 150                 blkdev_issue_flush(inode->i_sb->s_bdev, GFP_KERNEL, NULL,
 151                         BLKDEV_IFL_WAIT);
 152         if (barrier_done < 0)
 153                 return barrier_done;
 154         return (err < 0) ? -EIO : 0;
 155 }
 156
 157 /* taken fs/buffer.c:__block_commit_write */
 158 int reiserfs_commit_page(struct inode *inode, struct page *page,
 159                          unsigned from, unsigned to)
 160 {
 161         unsigned block_start, block_end;
 162         int partial = 0;
 163         unsigned blocksize;
 164         struct buffer_head *bh, *head;
 165         unsigned long i_size_index = inode->i_size >> PAGE_CACHE_SHIFT;
 166         int new;
 167         int logit = reiserfs_file_data_log(inode);
 168         struct super_block *s = inode->i_sb;
 169         int bh_per_page = PAGE_CACHE_SIZE / s->s_blocksize;
 170         struct reiserfs_transaction_handle th;
 171         int ret = 0;
 172
 173         th.t_trans_id = 0;
 174         blocksize = 1 << inode->i_blkbits;
 175
 176         if (logit) {
 177                 reiserfs_write_lock(s);
 178                 ret = journal_begin(&th, s, bh_per_page + 1);
 179                 if (ret)
 180                         goto drop_write_lock;
 181                 reiserfs_update_inode_transaction(inode);
 182         }
 183         for (bh = head = page_buffers(page), block_start = 0;
 184              bh != head || !block_start;
 185              block_start = block_end, bh = bh->b_this_page) {
 186
 187                 new = buffer_new(bh);
 188                 clear_buffer_new(bh);
 189                 block_end = block_start + blocksize;
 190                 if (block_end <= from || block_start >= to) {
 191                         if (!buffer_uptodate(bh))
 192                                 partial = 1;
 193                 } else {
 194                         set_buffer_uptodate(bh);
 195                         if (logit) {
 196                                 reiserfs_prepare_for_journal(s, bh, 1);
 197                                 journal_mark_dirty(&th, s, bh);
 198                         } else if (!buffer_dirty(bh)) {
 199                                 mark_buffer_dirty(bh);
 200                                 /* do data=ordered on any page past the end
 201                                  * of file and any buffer marked BH_New.
 202                                  */
 203                                 if (reiserfs_data_ordered(inode->i_sb) &&
 204                                     (new || page->index >= i_size_index)) {
 205                                         reiserfs_add_ordered_list(inode, bh);
 206                                 }
 207                         }
 208                 }
 209         }
 210         if (logit) {
 211                 ret = journal_end(&th, s, bh_per_page + 1);
 212               drop_write_lock:
 213                 reiserfs_write_unlock(s);
 214         }
 215         /*
 216          * If this is a partial write which happened to make all buffers
 217          * uptodate then we can optimize away a bogus readpage() for
 218          * the next read(). Here we 'discover' whether the page went
 219          * uptodate as a result of this (potentially partial) write.
 220          */
 221         if (!partial)
 222                 SetPageUptodate(page);
 223         return ret;
 224 }
 225
 226 /* Write @count bytes at position @ppos in a file indicated by @file
 227    from the buffer @buf.
 228
 229    generic_file_write() is only appropriate for filesystems that are not seeking to optimize performance and want
 230    something simple that works.  It is not for serious use by general purpose filesystems, excepting the one that it was
 231    written for (ext2/3).  This is for several reasons:
 232
 233    * It has no understanding of any filesystem specific optimizations.
 234
 235    * It enters the filesystem repeatedly for each page that is written.
 236
 237    * It depends on reiserfs_get_block() function which if implemented by reiserfs performs costly search_by_key
 238    * operation for each page it is supplied with. By contrast reiserfs_file_write() feeds as much as possible at a time
 239    * to reiserfs which allows for fewer tree traversals.
 240
 241    * Each indirect pointer insertion takes a lot of cpu, because it involves memory moves inside of blocks.
 242
 243    * Asking the block allocation code for blocks one at a time is slightly less efficient.
 244
 245    All of these reasons for not using only generic file write were understood back when reiserfs was first miscoded to
 246    use it, but we were in a hurry to make code freeze, and so it couldn't be revised then.  This new code should make
 247    things right finally.
 248
 249    Future Features: providing search_by_key with hints.
 250
 251 */
 252 static ssize_t reiserfs_file_write(struct file *file,   /* the file we are going to write into */
 253                                    const char __user * buf,     /*  pointer to user supplied data
 254                                                                    (in userspace) */
 255                                    size_t count,        /* amount of bytes to write */
 256                                    loff_t * ppos        /* pointer to position in file that we start writing at. Should be updated to
 257                                                          * new current position before returning. */
 258                                    )
 259 {
 260         struct inode *inode = file->f_path.dentry->d_inode;     // Inode of the file that we are writing to.
 261         /* To simplify coding at this time, we store
 262            locked pages in array for now */
 263         struct reiserfs_transaction_handle th;
 264         th.t_trans_id = 0;
 265
 266         /* If a filesystem is converted from 3.5 to 3.6, we'll have v3.5 items
 267         * lying around (most of the disk, in fact). Despite the filesystem
 268         * now being a v3.6 format, the old items still can't support large
 269         * file sizes. Catch this case here, as the rest of the VFS layer is
 270         * oblivious to the different limitations between old and new items.
 271         * reiserfs_setattr catches this for truncates. This chunk is lifted
 272         * from generic_write_checks. */
 273         if (get_inode_item_key_version (inode) == KEY_FORMAT_3_5 &&
 274             *ppos + count > MAX_NON_LFS) {
 275                 if (*ppos >= MAX_NON_LFS) {
 276                         return -EFBIG;
 277                 }
 278                 if (count > MAX_NON_LFS - (unsigned long)*ppos)
 279                         count = MAX_NON_LFS - (unsigned long)*ppos;
 280         }
 281
 282         return do_sync_write(file, buf, count, ppos);
 283 }
 284
 285 const struct file_operations reiserfs_file_operations = {
 286         .read = do_sync_read,
 287         .write = reiserfs_file_write,
 288         .unlocked_ioctl = reiserfs_ioctl,
 289 #ifdef CONFIG_COMPAT
 290         .compat_ioctl = reiserfs_compat_ioctl,
 291 #endif
 292         .mmap = reiserfs_file_mmap,
 293         .open = dquot_file_open,
 294         .release = reiserfs_file_release,
 295         .fsync = reiserfs_sync_file,
 296         .aio_read = generic_file_aio_read,
 297         .aio_write = generic_file_aio_write,
 298         .splice_read = generic_file_splice_read,
 299         .splice_write = generic_file_splice_write,
 300         .llseek = generic_file_llseek,
 301 };
 302
 303 const struct inode_operations reiserfs_file_inode_operations = {
 304         .truncate = reiserfs_vfs_truncate_file,
 305         .setattr = reiserfs_setattr,
 306         .setxattr = reiserfs_setxattr,
 307         .getxattr = reiserfs_getxattr,
 308         .listxattr = reiserfs_listxattr,
 309         .removexattr = reiserfs_removexattr,
 310         .permission = reiserfs_permission,
 311 };