--- /dev/null
+/*
+ * linux/include/linux/jfs.h
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>
+ *
+ * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * Definitions for transaction data structures for the buffer cache
+ * filesystem journaling support.
+ */
+
+#ifndef _LINUX_JFS_H
+#define _LINUX_JFS_H
+
+/* Allow this file to be included directly into e2fsprogs */
+#ifndef __KERNEL__
+#include "jfs_compat.h"
+#endif
+
+/*
+ * Debug code enabled by default for kernel builds
+ */
+#ifdef __KERNEL__
+#define JFS_DEBUG
+#else
+#define JFS_DEBUG
+#endif
+
+extern int journal_enable_debug;
+
+#ifdef JFS_DEBUG
+#define jfs_debug(n, f, a...) \
+ do { \
+ if ((n) <= journal_enable_debug) { \
+ printk (KERN_DEBUG "JFS DEBUG: (%s, %d): %s: ", \
+ __FILE__, __LINE__, __FUNCTION__); \
+ printk (f, a); \
+ } \
+ } while (0)
+#else
+#define jfs_debug(f, a...) /**/
+#endif
+
+#define JFS_MIN_JOURNAL_BLOCKS 1024
+
+/*
+ * Internal structures used by the logging mechanism:
+ */
+
+#define JFS_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
+
+
+/*
+ * On-disk structures
+ */
+
+/*
+ * Descriptor block types:
+ */
+
+#define JFS_DESCRIPTOR_BLOCK 1
+#define JFS_COMMIT_BLOCK 2
+#define JFS_SUPERBLOCK_V1 3
+#define JFS_SUPERBLOCK_V2 4
+#define JFS_REVOKE_BLOCK 5
+
+/*
+ * Standard header for all descriptor blocks:
+ */
+typedef struct journal_header_s
+{
+ __u32 h_magic;
+ __u32 h_blocktype;
+ __u32 h_sequence;
+} journal_header_t;
+
+
+/*
+ * The block tag: used to describe a single buffer in the journal
+ */
+typedef struct journal_block_tag_s
+{
+ __u32 t_blocknr; /* The on-disk block number */
+ __u32 t_flags; /* See below */
+} journal_block_tag_t;
+
+/*
+ * The revoke descriptor: used on disk to describe a series of blocks to
+ * be revoked from the log
+ */
+typedef struct journal_revoke_header_s
+{
+ journal_header_t r_header;
+ int r_count; /* Count of bytes used in the block */
+} journal_revoke_header_t;
+
+
+/* Definitions for the journal tag flags word: */
+#define JFS_FLAG_ESCAPE 1 /* on-disk block is escaped */
+#define JFS_FLAG_SAME_UUID 2 /* block has same uuid as previous */
+#define JFS_FLAG_DELETED 4 /* block deleted by this transaction */
+#define JFS_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
+
+
+/*
+ * The journal superblock. All fields are in big-endian byte order.
+ */
+typedef struct journal_superblock_s
+{
+/* 0x0000 */
+ journal_header_t s_header;
+
+/* 0x000C */
+ /* Static information describing the journal */
+ __u32 s_blocksize; /* journal device blocksize */
+ __u32 s_maxlen; /* total blocks in journal file */
+ __u32 s_first; /* first block of log information */
+
+/* 0x0018 */
+ /* Dynamic information describing the current state of the log */
+ __u32 s_sequence; /* first commit ID expected in log */
+ __u32 s_start; /* blocknr of start of log */
+
+/* 0x0020 */
+ /* Error value, as set by journal_abort(). */
+ __s32 s_errno;
+
+/* 0x0024 */
+ /* Remaining fields are only valid in a version-2 superblock */
+ __u32 s_feature_compat; /* compatible feature set */
+ __u32 s_feature_incompat; /* incompatible feature set */
+ __u32 s_feature_ro_compat; /* readonly-compatible feature set */
+/* 0x0030 */
+ __u8 s_uuid[16]; /* 128-bit uuid for journal */
+
+/* 0x0040 */
+ __u32 s_nr_users; /* Nr of filesystems sharing log */
+
+ __u32 s_dynsuper; /* Blocknr of dynamic superblock copy*/
+
+/* 0x0048 */
+ __u32 s_max_transaction; /* Limit of journal blocks per trans.*/
+ __u32 s_max_trans_data; /* Limit of data blocks per trans. */
+
+/* 0x0050 */
+ __u32 s_padding[44];
+
+/* 0x0100 */
+ __u8 s_users[16*48]; /* ids of all fs'es sharing the log */
+/* 0x0400 */
+} journal_superblock_t;
+
+#define JFS_HAS_COMPAT_FEATURE(j,mask) \
+ ((j)->j_format_version >= 2 && \
+ ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
+#define JFS_HAS_RO_COMPAT_FEATURE(j,mask) \
+ ((j)->j_format_version >= 2 && \
+ ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
+#define JFS_HAS_INCOMPAT_FEATURE(j,mask) \
+ ((j)->j_format_version >= 2 && \
+ ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
+
+#define JFS_FEATURE_INCOMPAT_REVOKE 0x00000001
+
+/* Features known to this kernel version: */
+#define JFS_KNOWN_COMPAT_FEATURES 0
+#define JFS_KNOWN_ROCOMPAT_FEATURES 0
+#define JFS_KNOWN_INCOMPAT_FEATURES JFS_FEATURE_INCOMPAT_REVOKE
+
+#ifdef __KERNEL__
+
+#include <linux/fs.h>
+
+
+#define J_ASSERT(assert) \
+ do { if (!(assert)) { \
+ printk (KERN_EMERG \
+ "Assertion failure in %s() at %s line %d: " \
+ "\"%s\"\n", \
+ __FUNCTION__, __FILE__, __LINE__, # assert); \
+ * ((char *) 0) = 0; \
+ } } while (0)
+
+
+struct jfs_revoke_table_s;
+
+/* The handle_t type represents a single atomic update being performed
+ * by some process. All filesystem modifications made by the process go
+ * through this handle. Recursive operations (such as quota operations)
+ * are gathered into a single update.
+ *
+ * The buffer credits field is used to account for journaled buffers
+ * being modified by the running process. To ensure that there is
+ * enough log space for all outstanding operations, we need to limit the
+ * number of outstanding buffers possible at any time. When the
+ * operation completes, any buffer credits not used are credited back to
+ * the transaction, so that at all times we know how many buffers the
+ * outstanding updates on a transaction might possibly touch. */
+
+struct handle_s
+{
+ /* Which compound transaction is this update a part of? */
+ transaction_t * h_transaction;
+
+ /* Number of remaining buffers we are allowed to dirty: */
+ int h_buffer_credits;
+
+ /* Reference count on this handle */
+ int h_ref;
+
+ /* Flags */
+ unsigned int h_sync : 1; /* sync-on-close */
+ unsigned int h_jdata : 1; /* force data journaling */
+};
+
+
+/* The transaction_t type is the guts of the journaling mechanism. It
+ * tracks a compound transaction through its various states:
+ *
+ * RUNNING: accepting new updates
+ * LOCKED: Updates still running but we don't accept new ones
+ * RUNDOWN: Updates are tidying up but have finished requesting
+ * new buffers to modify (state not used for now)
+ * FLUSH: All updates complete, but we are still writing to disk
+ * COMMIT: All data on disk, writing commit record
+ * FINISHED: We still have to keep the transaction for checkpointing.
+ *
+ * The transaction keeps track of all of the buffers modified by a
+ * running transaction, and all of the buffers committed but not yet
+ * flushed to home for finished transactions.
+ */
+
+struct transaction_s
+{
+ /* Pointer to the journal for this transaction. */
+ journal_t * t_journal;
+
+ /* Sequence number for this transaction */
+ tid_t t_tid;
+
+ /* Transaction's current state */
+ enum {
+ T_RUNNING,
+ T_LOCKED,
+ T_RUNDOWN,
+ T_FLUSH,
+ T_COMMIT,
+ T_FINISHED
+ } t_state;
+
+ /* Where in the log does this transaction's commit start? */
+ unsigned long t_log_start;
+
+ /* Doubly-linked circular list of all inodes owned by this
+ transaction */
+ struct inode * t_ilist;
+
+ /* Number of buffers on the t_buffers list */
+ int t_nr_buffers;
+
+ /* Doubly-linked circular list of all buffers reserved but not
+ yet modified by this transaction */
+ struct buffer_head * t_reserved_list;
+
+ /* Doubly-linked circular list of all metadata buffers owned by this
+ transaction */
+ struct buffer_head * t_buffers;
+
+ /* Doubly-linked circular list of all data buffers still to be
+ flushed before this transaction can be committed */
+ struct buffer_head * t_datalist;
+
+ /* Doubly-linked circular list of all forget buffers (superceded
+ buffers which we can un-checkpoint once this transaction
+ commits) */
+ struct buffer_head * t_forget;
+
+ /* Doubly-linked circular list of all buffers still to be
+ flushed before this transaction can be checkpointed */
+ struct buffer_head * t_checkpoint_list;
+
+ /* Doubly-linked circular list of temporary buffers currently
+ undergoing IO in the log */
+ struct buffer_head * t_iobuf_list;
+
+ /* Doubly-linked circular list of metadata buffers being
+ shadowed by log IO. The IO buffers on the iobuf list and the
+ shadow buffers on this list match each other one for one at
+ all times. */
+ struct buffer_head * t_shadow_list;
+
+ /* Doubly-linked circular list of control buffers being written
+ to the log. */
+ struct buffer_head * t_log_list;
+
+ /* Number of outstanding updates running on this transaction */
+ int t_updates;
+
+ /* Number of buffers reserved for use by all handles in this
+ * transaction handle but not yet modified. */
+ int t_outstanding_credits;
+
+ /* Wait queue to wait for updates to complete */
+ struct wait_queue * t_wait;
+
+ /* Forward and backward links for the circular list of all
+ * transactions awaiting checkpoint */
+ transaction_t *t_cpnext, *t_cpprev;
+
+ /* When will the transaction expire (become due for commit), in
+ * jiffies ? */
+ unsigned long t_expires;
+};
+
+
+/* The journal_t maintains all of the journaling state information for a
+ * single filesystem. It is linked to from the fs superblock structure.
+ *
+ * We use the journal_t to keep track of all outstanding transaction
+ * activity on the filesystem, and to manage the state of the log
+ * writing process. */
+
+struct journal_s
+{
+ /* General journaling state flags */
+ unsigned long j_flags;
+
+ /* Is there an outstanding uncleared error on the journal (from
+ * a prior abort)? */
+ int j_errno;
+
+ /* The superblock buffer */
+ struct buffer_head * j_sb_buffer;
+ journal_superblock_t * j_superblock;
+
+ /* Version of the superblock format */
+ int j_format_version;
+
+ /* Transactions: The current running transaction... */
+ transaction_t * j_running_transaction;
+
+ /* ... the transaction we are pushing to disk ... */
+ transaction_t * j_committing_transaction;
+
+ /* ... and a linked circular list of all transactions waiting
+ * for checkpointing. */
+ transaction_t * j_checkpoint_transactions;
+
+ /* Wait queue for locking of the journal structure. */
+ struct wait_queue * j_wait_lock;
+
+ /* Wait queue for waiting for a locked transaction to start
+ committing */
+ struct wait_queue * j_wait_transaction_locked;
+
+ /* Wait queue for waiting for checkpointing to complete */
+ struct wait_queue * j_wait_logspace;
+
+ /* Wait queue for waiting for commit to complete */
+ struct wait_queue * j_wait_done_commit;
+
+ /* Wait queue to trigger checkpointing */
+ struct wait_queue * j_wait_checkpoint;
+
+ /* Wait queue to trigger commit */
+ struct wait_queue * j_wait_commit;
+
+ /* Semaphore for locking against concurrent checkpoints */
+ struct semaphore j_checkpoint_sem;
+
+ /* Journal running state: */
+ /* The lock flag is *NEVER* touched from interrupts. */
+ unsigned int j_locked : 1;
+
+ /* Journal head: identifies the first unused block in the journal. */
+ unsigned long j_head;
+
+ /* Journal tail: identifies the oldest still-used block in the
+ * journal. */
+ unsigned long j_tail;
+
+ /* Journal free: how many free blocks are there in the journal? */
+ unsigned long j_free;
+
+ /* Journal start and end: the block numbers of the first usable
+ * block and one beyond the last usable block in the journal. */
+ unsigned long j_first, j_last;
+
+ /* Device, blocksize and starting block offset for the location
+ * where we store the journal. */
+ kdev_t j_dev;
+ int j_blocksize;
+ unsigned int j_blk_offset;
+
+ /* Total maximum capacity of the journal region on disk. */
+ unsigned int j_maxlen;
+
+ /* Optional inode where we store the journal. If present, all
+ * journal block numbers are mapped into this inode via
+ * bmap(). */
+ struct inode * j_inode;
+
+ /* Sequence number of the oldest transaction in the log */
+ tid_t j_tail_sequence;
+ /* Sequence number of the next transaction to grant */
+ tid_t j_transaction_sequence;
+ /* Sequence number of the most recently committed transaction */
+ tid_t j_commit_sequence;
+ /* Sequence number of the most recent transaction wanting commit */
+ tid_t j_commit_request;
+
+ /* Journal uuid: identifies the object (filesystem, LVM volume
+ * etc) backed by this journal. This will eventually be
+ * replaced by an array of uuids, allowing us to index multiple
+ * devices within a single journal and to perform atomic updates
+ * across them. */
+
+ __u8 j_uuid[16];
+
+ /* Pointer to the current commit thread for this journal */
+ struct task_struct * j_task;
+
+ /* Maximum number of metadata buffers to allow in a single
+ * compound commit transaction */
+ int j_max_transaction_buffers;
+
+ /* What is the maximum transaction lifetime before we begin a
+ * commit? */
+ unsigned long j_commit_interval;
+
+ /* The timer used to wakeup the commit thread: */
+ struct timer_list * j_commit_timer;
+ int j_commit_timer_active;
+
+ /* The revoke table: maintains the list of revoked blocks in the
+ current transaction. */
+ struct jfs_revoke_table_s *j_revoke;
+};
+
+/*
+ * Journal flag definitions
+ */
+#define JFS_UNMOUNT 1 /* Journal thread is being destroyed */
+#define JFS_SYNC 2 /* Perform synchronous transaction commits */
+#define JFS_ABORT 4 /* Journaling has been aborted for errors. */
+#define JFS_ACK_ERR 8 /* The errno in the sb has been acked */
+
+/*
+ * Journaling internal variables/parameters
+ */
+
+extern int journal_flush_nr_buffers;
+
+
+/*
+ * Function declarations for the journaling transaction and buffer
+ * management
+ */
+
+/* Filing buffers */
+extern void journal_unfile_buffer(struct buffer_head *);
+extern void journal_refile_buffer(struct buffer_head *);
+extern void journal_file_buffer(struct buffer_head *, transaction_t *, int);
+extern void journal_clean_data_list(transaction_t *transaction);
+
+/* Log buffer allocation */
+extern struct buffer_head * journal_get_descriptor_buffer(journal_t *);
+extern unsigned long journal_next_log_block(journal_t *);
+
+/* Commit management */
+extern void journal_commit_transaction(journal_t *);
+
+/* Checkpoint list management */
+extern void journal_remove_checkpoint(struct buffer_head *);
+extern void journal_insert_checkpoint(struct buffer_head *, transaction_t *);
+
+/* Buffer IO */
+extern int
+journal_write_metadata_buffer(transaction_t *transaction,
+ struct buffer_head *bh_in,
+ struct buffer_head **bh_out,
+ int blocknr);
+
+/* Create and destroy transactions */
+extern transaction_t * get_transaction (journal_t *);
+extern void put_transaction (transaction_t *);
+
+/* Notify state transitions (called by the log writer thread): */
+extern int set_transaction_state (transaction_t *, int);
+
+
+/* Transaction locking */
+extern void __wait_on_journal (journal_t *);
+
+/* Journal locking. In 2.2, we assume that the kernel lock is already
+ * held. */
+static inline void lock_journal (journal_t * journal)
+{
+#ifdef __SMP__
+ J_ASSERT(current->lock_depth >= 0);
+#endif
+ if (journal->j_locked)
+ __wait_on_journal(journal);
+ journal->j_locked = 1;
+}
+
+static inline int try_lock_journal (journal_t * journal)
+{
+ if (journal->j_locked)
+ return 1;
+ journal->j_locked = 1;
+ return 0;
+}
+
+static inline void unlock_journal (journal_t * journal)
+{
+ J_ASSERT (journal->j_locked);
+ journal->j_locked = 0;
+ wake_up(&journal->j_wait_lock);
+}
+
+/* This function is gross, but unfortunately we need it as long as
+ * existing filesystems want to guard against races by testing
+ * bh->b_count. @@@ Remove this? We no longer abuse b_count so badly!
+ */
+
+static inline int journal_is_buffer_shared(struct buffer_head *bh)
+{
+ int count = bh->b_count;
+ J_ASSERT (count >= 1);
+ return (count > 1);
+}
+
+/* The journaling code user interface:
+ *
+ * Create and destroy handles
+ * Register buffer modifications against the current transaction.
+ */
+
+extern handle_t *journal_start (journal_t *, int nblocks);
+extern int journal_restart (handle_t *, int nblocks);
+extern int journal_extend (handle_t *, int nblocks);
+extern int journal_get_write_access (handle_t *, struct buffer_head *);
+extern int journal_get_create_access (handle_t *, struct buffer_head *);
+extern int journal_get_undo_access (handle_t *, struct buffer_head *);
+extern int journal_dirty_data (handle_t *, struct buffer_head *);
+extern int journal_dirty_metadata (handle_t *, struct buffer_head *);
+extern void journal_release_buffer (handle_t *, struct buffer_head *);
+extern void journal_forget (handle_t *, struct buffer_head *);
+extern void journal_sync_buffer (struct buffer_head *);
+extern int journal_stop (handle_t *);
+extern int journal_flush (journal_t *);
+
+extern journal_t * journal_init_dev (kdev_t, int start, int len, int bsize);
+extern journal_t * journal_init_inode (struct inode *);
+extern int journal_update_format (journal_t *);
+extern int journal_check_used_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int journal_check_available_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int journal_set_features
+ (journal_t *, unsigned long, unsigned long, unsigned long);
+extern int journal_create (journal_t *);
+extern int journal_load (journal_t *);
+extern void journal_release (journal_t *);
+extern int journal_recover (journal_t *);
+extern void journal_update_superblock (journal_t *, int);
+extern void __journal_abort (journal_t *);
+extern void journal_abort (journal_t *, int);
+extern int journal_errno (journal_t *);
+extern void journal_ack_err (journal_t *);
+extern int journal_clear_err (journal_t *);
+
+/* Primary revoke support */
+#define JOURNAL_REVOKE_DEFAULT_HASH 256
+extern int journal_init_revoke(journal_t *, int);
+extern void journal_destroy_revoke(journal_t *);
+extern int journal_revoke (handle_t *, unsigned long, struct buffer_head *);
+extern void journal_cancel_revoke(handle_t *, struct buffer_head *);
+extern void journal_write_revoke_records(journal_t *, transaction_t *);
+
+/* Recovery revoke support */
+extern int journal_set_revoke(journal_t *, unsigned long, tid_t);
+extern int journal_test_revoke(journal_t *, unsigned long, tid_t);
+extern void journal_clear_revoke(journal_t *);
+
+
+/* The log thread user interface:
+ *
+ * Request space in the current transaction, and force transaction commit
+ * transitions on demand.
+ */
+
+extern int log_space_left (journal_t *); /* Called with journal locked */
+extern void log_start_commit (journal_t *, transaction_t *);
+extern void log_wait_commit (journal_t *, tid_t);
+extern int log_do_checkpoint (journal_t *, int);
+
+extern void log_wait_for_space(journal_t *, int nblocks);
+extern void journal_drop_transaction(journal_t *, transaction_t *);
+extern int cleanup_journal_tail(journal_t *);
+
+
+/* Debugging code only: */
+
+#define jfs_ENOSYS() \
+do { \
+ printk (KERN_ERR "JFS unimplemented function " __FUNCTION__); \
+ current->state = TASK_UNINTERRUPTIBLE; \
+ schedule(); \
+} while (1)
+
+/*
+ * is_journal_abort
+ *
+ * Simple test wrapper function to test the JFS_ABORT state flag. This
+ * bit, when set, indicates that we have had a fatal error somewhere,
+ * either inside the journaling layer or indicated to us by the client
+ * (eg. ext3), and that we and should not commit any further
+ * transactions.
+ */
+
+static inline int is_journal_abort(journal_t *journal)
+{
+ return journal->j_flags & JFS_ABORT;
+}
+
+#endif /* __KERNEL__ */
+
+/* Comparison functions for transaction IDs: perform comparisons using
+ * modulo arithmetic so that they work over sequence number wraps. */
+
+static inline int tid_ge(tid_t x, tid_t y)
+{
+ int difference = (x - y);
+ return (difference > 0);
+}
+
+static inline int tid_geq(tid_t x, tid_t y)
+{
+ int difference = (x - y);
+ return (difference >= 0);
+}
+
+
+#endif /* _LINUX_JFS_H */
projects / thirdparty / e2fsprogs.git / commitdiff
