2 * linux/include/linux/jbd2.h
4 * Written by Stephen C. Tweedie <sct@redhat.com>
6 * Copyright 1998-2000 Red Hat, Inc --- All Rights Reserved
8 * This file is part of the Linux kernel and is made available under
9 * the terms of the GNU General Public License, version 2, or at your
10 * option, any later version, incorporated herein by reference.
12 * Definitions for transaction data structures for the buffer cache
13 * filesystem journaling support.
19 /* Allow this file to be included directly into e2fsprogs */
21 #include "jfs_compat.h"
25 #include <linux/types.h>
26 #include <linux/buffer_head.h>
27 #include <linux/journal-head.h>
28 #include <linux/stddef.h>
29 #include <linux/mutex.h>
30 #include <linux/timer.h>
31 #include <linux/slab.h>
32 #include <linux/bit_spinlock.h>
33 #include <crypto/hash.h>
36 #define journal_oom_retry 1
39 * Define JBD2_PARANIOD_IOFAIL to cause a kernel BUG() if ext4 finds
40 * certain classes of error which can occur due to failed IOs. Under
41 * normal use we want ext4 to continue after such errors, because
42 * hardware _can_ fail, but for debugging purposes when running tests on
43 * known-good hardware we may want to trap these errors.
45 #undef JBD2_PARANOID_IOFAIL
48 * The default maximum commit age, in seconds.
50 #define JBD2_DEFAULT_MAX_COMMIT_AGE 5
52 #ifdef CONFIG_JBD2_DEBUG
54 * Define JBD2_EXPENSIVE_CHECKING to enable more expensive internal
55 * consistency checks. By default we don't do this unless
56 * CONFIG_JBD2_DEBUG is on.
58 #define JBD2_EXPENSIVE_CHECKING
59 extern ushort jbd2_journal_enable_debug;
60 void __jbd2_debug(int level, const char *file, const char *func,
61 unsigned int line, const char *fmt, ...);
63 #define jbd_debug(n, fmt, a...) \
64 __jbd2_debug((n), __FILE__, __func__, __LINE__, (fmt), ##a)
66 #define jbd_debug(n, fmt, a...) /**/
69 extern void *jbd2_alloc(size_t size, gfp_t flags);
70 extern void jbd2_free(void *ptr, size_t size);
72 #define JBD2_MIN_JOURNAL_BLOCKS 1024
77 * typedef handle_t - The handle_t type represents a single atomic update being performed by some process.
79 * All filesystem modifications made by the process go
80 * through this handle. Recursive operations (such as quota operations)
81 * are gathered into a single update.
83 * The buffer credits field is used to account for journaled buffers
84 * being modified by the running process. To ensure that there is
85 * enough log space for all outstanding operations, we need to limit the
86 * number of outstanding buffers possible at any time. When the
87 * operation completes, any buffer credits not used are credited back to
88 * the transaction, so that at all times we know how many buffers the
89 * outstanding updates on a transaction might possibly touch.
91 * This is an opaque datatype.
93 typedef struct jbd2_journal_handle handle_t; /* Atomic operation type */
97 * typedef journal_t - The journal_t maintains all of the journaling state information for a single filesystem.
99 * journal_t is linked to from the fs superblock structure.
101 * We use the journal_t to keep track of all outstanding transaction
102 * activity on the filesystem, and to manage the state of the log
105 * This is an opaque datatype.
107 typedef struct journal_s journal_t; /* Journal control structure */
111 * Internal structures used by the logging mechanism:
114 #define JBD2_MAGIC_NUMBER 0xc03b3998U /* The first 4 bytes of /dev/random! */
121 * Descriptor block types:
124 #define JBD2_DESCRIPTOR_BLOCK 1
125 #define JBD2_COMMIT_BLOCK 2
126 #define JBD2_SUPERBLOCK_V1 3
127 #define JBD2_SUPERBLOCK_V2 4
128 #define JBD2_REVOKE_BLOCK 5
131 * Standard header for all descriptor blocks:
133 typedef struct journal_header_s
143 #define JBD2_CRC32_CHKSUM 1
144 #define JBD2_MD5_CHKSUM 2
145 #define JBD2_SHA1_CHKSUM 3
146 #define JBD2_CRC32C_CHKSUM 4
148 #define JBD2_CRC32_CHKSUM_SIZE 4
150 #define JBD2_CHECKSUM_BYTES (32 / sizeof(u32))
152 * Commit block header for storing transactional checksums:
154 * NOTE: If FEATURE_COMPAT_CHECKSUM (checksum v1) is set, the h_chksum*
155 * fields are used to store a checksum of the descriptor and data blocks.
157 * If FEATURE_INCOMPAT_CSUM_V2 (checksum v2) is set, then the h_chksum
158 * field is used to store crc32c(uuid+commit_block). Each journal metadata
159 * block gets its own checksum, and data block checksums are stored in
160 * journal_block_tag (in the descriptor). The other h_chksum* fields are
163 * If FEATURE_INCOMPAT_CSUM_V3 is set, the descriptor block uses
164 * journal_block_tag3_t to store a full 32-bit checksum. Everything else
167 * Checksum v1, v2, and v3 are mutually exclusive features.
169 struct commit_header {
173 unsigned char h_chksum_type;
174 unsigned char h_chksum_size;
175 unsigned char h_padding[2];
176 __be32 h_chksum[JBD2_CHECKSUM_BYTES];
178 __be32 h_commit_nsec;
182 * The block tag: used to describe a single buffer in the journal.
183 * t_blocknr_high is only used if INCOMPAT_64BIT is set, so this
184 * raw struct shouldn't be used for pointer math or sizeof() - use
185 * journal_tag_bytes(journal) instead to compute this.
187 typedef struct journal_block_tag3_s
189 __be32 t_blocknr; /* The on-disk block number */
190 __be32 t_flags; /* See below */
191 __be32 t_blocknr_high; /* most-significant high 32bits. */
192 __be32 t_checksum; /* crc32c(uuid+seq+block) */
193 } journal_block_tag3_t;
195 typedef struct journal_block_tag_s
197 __be32 t_blocknr; /* The on-disk block number */
198 __be16 t_checksum; /* truncated crc32c(uuid+seq+block) */
199 __be16 t_flags; /* See below */
200 __be32 t_blocknr_high; /* most-significant high 32bits. */
201 } journal_block_tag_t;
203 /* Tail of descriptor or revoke block, for checksumming */
204 struct jbd2_journal_block_tail {
205 __be32 t_checksum; /* crc32c(uuid+descr_block) */
209 * The revoke descriptor: used on disk to describe a series of blocks to
210 * be revoked from the log
212 typedef struct jbd2_journal_revoke_header_s
214 journal_header_t r_header;
215 __be32 r_count; /* Count of bytes used in the block */
216 } jbd2_journal_revoke_header_t;
218 /* Definitions for the journal tag flags word: */
219 #define JBD2_FLAG_ESCAPE 1 /* on-disk block is escaped */
220 #define JBD2_FLAG_SAME_UUID 2 /* block has same uuid as previous */
221 #define JBD2_FLAG_DELETED 4 /* block deleted by this transaction */
222 #define JBD2_FLAG_LAST_TAG 8 /* last tag in this descriptor block */
226 * The journal superblock. All fields are in big-endian byte order.
228 typedef struct journal_superblock_s
231 journal_header_t s_header;
234 /* Static information describing the journal */
235 __be32 s_blocksize; /* journal device blocksize */
236 __be32 s_maxlen; /* total blocks in journal file */
237 __be32 s_first; /* first block of log information */
240 /* Dynamic information describing the current state of the log */
241 __be32 s_sequence; /* first commit ID expected in log */
242 __be32 s_start; /* blocknr of start of log */
245 /* Error value, as set by jbd2_journal_abort(). */
249 /* Remaining fields are only valid in a version-2 superblock */
250 __be32 s_feature_compat; /* compatible feature set */
251 __be32 s_feature_incompat; /* incompatible feature set */
252 __be32 s_feature_ro_compat; /* readonly-compatible feature set */
254 __u8 s_uuid[16]; /* 128-bit uuid for journal */
257 __be32 s_nr_users; /* Nr of filesystems sharing log */
259 __be32 s_dynsuper; /* Blocknr of dynamic superblock copy*/
262 __be32 s_max_transaction; /* Limit of journal blocks per trans.*/
263 __be32 s_max_trans_data; /* Limit of data blocks per trans. */
266 __u8 s_checksum_type; /* checksum type */
269 __be32 s_checksum; /* crc32c(superblock) */
272 __u8 s_users[16*48]; /* ids of all fs'es sharing the log */
274 } journal_superblock_t;
276 /* Use the jbd2_{has,set,clear}_feature_* helpers; these will be removed */
277 #define JBD2_HAS_COMPAT_FEATURE(j,mask) \
278 ((j)->j_format_version >= 2 && \
279 ((j)->j_superblock->s_feature_compat & cpu_to_be32((mask))))
280 #define JBD2_HAS_RO_COMPAT_FEATURE(j,mask) \
281 ((j)->j_format_version >= 2 && \
282 ((j)->j_superblock->s_feature_ro_compat & cpu_to_be32((mask))))
283 #define JBD2_HAS_INCOMPAT_FEATURE(j,mask) \
284 ((j)->j_format_version >= 2 && \
285 ((j)->j_superblock->s_feature_incompat & cpu_to_be32((mask))))
287 #define JBD2_FEATURE_COMPAT_CHECKSUM 0x00000001
289 #define JBD2_FEATURE_INCOMPAT_REVOKE 0x00000001
290 #define JBD2_FEATURE_INCOMPAT_64BIT 0x00000002
291 #define JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT 0x00000004
292 #define JBD2_FEATURE_INCOMPAT_CSUM_V2 0x00000008
293 #define JBD2_FEATURE_INCOMPAT_CSUM_V3 0x00000010
295 /* See "journal feature predicate functions" below */
297 /* Features known to this kernel version: */
298 #define JBD2_KNOWN_COMPAT_FEATURES JBD2_FEATURE_COMPAT_CHECKSUM
299 #define JBD2_KNOWN_ROCOMPAT_FEATURES 0
300 #define JBD2_KNOWN_INCOMPAT_FEATURES (JBD2_FEATURE_INCOMPAT_REVOKE | \
301 JBD2_FEATURE_INCOMPAT_64BIT | \
302 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT | \
303 JBD2_FEATURE_INCOMPAT_CSUM_V2 | \
304 JBD2_FEATURE_INCOMPAT_CSUM_V3)
308 #include <linux/fs.h>
309 #include <linux/sched.h>
311 enum jbd_state_bits {
312 BH_JBD /* Has an attached ext3 journal_head */
314 BH_JWrite, /* Being written to log (@@@ DEBUGGING) */
315 BH_Freed, /* Has been freed (truncated) */
316 BH_Revoked, /* Has been revoked from the log */
317 BH_RevokeValid, /* Revoked flag is valid */
318 BH_JBDDirty, /* Is dirty but journaled */
319 BH_State, /* Pins most journal_head state */
320 BH_JournalHead, /* Pins bh->b_private and jh->b_bh */
321 BH_Shadow, /* IO on shadow buffer is running */
322 BH_Verified, /* Metadata block has been verified ok */
323 BH_JBDPrivateStart, /* First bit available for private use by FS */
327 BUFFER_FNS(JWrite, jwrite)
328 BUFFER_FNS(JBDDirty, jbddirty)
329 TAS_BUFFER_FNS(JBDDirty, jbddirty)
330 BUFFER_FNS(Revoked, revoked)
331 TAS_BUFFER_FNS(Revoked, revoked)
332 BUFFER_FNS(RevokeValid, revokevalid)
333 TAS_BUFFER_FNS(RevokeValid, revokevalid)
334 BUFFER_FNS(Freed, freed)
335 BUFFER_FNS(Shadow, shadow)
336 BUFFER_FNS(Verified, verified)
338 static inline struct buffer_head *jh2bh(struct journal_head *jh)
343 static inline struct journal_head *bh2jh(struct buffer_head *bh)
345 return bh->b_private;
348 static inline void jbd_lock_bh_state(struct buffer_head *bh)
350 bit_spin_lock(BH_State, &bh->b_state);
353 static inline int jbd_trylock_bh_state(struct buffer_head *bh)
355 return bit_spin_trylock(BH_State, &bh->b_state);
358 static inline int jbd_is_locked_bh_state(struct buffer_head *bh)
360 return bit_spin_is_locked(BH_State, &bh->b_state);
363 static inline void jbd_unlock_bh_state(struct buffer_head *bh)
365 bit_spin_unlock(BH_State, &bh->b_state);
368 static inline void jbd_lock_bh_journal_head(struct buffer_head *bh)
370 bit_spin_lock(BH_JournalHead, &bh->b_state);
373 static inline void jbd_unlock_bh_journal_head(struct buffer_head *bh)
375 bit_spin_unlock(BH_JournalHead, &bh->b_state);
378 #define J_ASSERT(assert) BUG_ON(!(assert))
380 #define J_ASSERT_BH(bh, expr) J_ASSERT(expr)
381 #define J_ASSERT_JH(jh, expr) J_ASSERT(expr)
383 #if defined(JBD2_PARANOID_IOFAIL)
384 #define J_EXPECT(expr, why...) J_ASSERT(expr)
385 #define J_EXPECT_BH(bh, expr, why...) J_ASSERT_BH(bh, expr)
386 #define J_EXPECT_JH(jh, expr, why...) J_ASSERT_JH(jh, expr)
388 #define __journal_expect(expr, why...) \
393 "JBD2 unexpected failure: %s: %s;\n", \
395 printk(KERN_ERR why "\n"); \
399 #define J_EXPECT(expr, why...) __journal_expect(expr, ## why)
400 #define J_EXPECT_BH(bh, expr, why...) __journal_expect(expr, ## why)
401 #define J_EXPECT_JH(jh, expr, why...) __journal_expect(expr, ## why)
404 /* Flags in jbd_inode->i_flags */
405 #define __JI_COMMIT_RUNNING 0
406 #define __JI_WRITE_DATA 1
407 #define __JI_WAIT_DATA 2
410 * Commit of the inode data in progress. We use this flag to protect us from
411 * concurrent deletion of inode. We cannot use reference to inode for this
412 * since we cannot afford doing last iput() on behalf of kjournald
414 #define JI_COMMIT_RUNNING (1 << __JI_COMMIT_RUNNING)
415 /* Write allocated dirty buffers in this inode before commit */
416 #define JI_WRITE_DATA (1 << __JI_WRITE_DATA)
417 /* Wait for outstanding data writes for this inode before commit */
418 #define JI_WAIT_DATA (1 << __JI_WAIT_DATA)
421 * struct jbd_inode - The jbd_inode type is the structure linking inodes in
422 * ordered mode present in a transaction so that we can sync them during commit.
428 * Which transaction does this inode belong to? Either the running
429 * transaction or the committing one. [j_list_lock]
431 transaction_t *i_transaction;
434 * @i_next_transaction:
436 * Pointer to the running transaction modifying inode's data in case
437 * there is already a committing transaction touching it. [j_list_lock]
439 transaction_t *i_next_transaction;
442 * @i_list: List of inodes in the i_transaction [j_list_lock]
444 struct list_head i_list;
449 * VFS inode this inode belongs to [constant for lifetime of structure]
451 struct inode *i_vfs_inode;
454 * @i_flags: Flags of inode [j_list_lock]
456 unsigned long i_flags;
461 * Offset in bytes where the dirty range for this inode starts.
464 loff_t i_dirty_start;
469 * Inclusive offset in bytes where the dirty range for this inode
470 * ends. [j_list_lock]
475 struct jbd2_revoke_table_s;
478 * struct handle_s - The handle_s type is the concrete type associated with
480 * @h_transaction: Which compound transaction is this update a part of?
481 * @h_journal: Which journal handle belongs to - used iff h_reserved set.
482 * @h_rsv_handle: Handle reserved for finishing the logical operation.
483 * @h_buffer_credits: Number of remaining buffers we are allowed to dirty.
484 * @h_ref: Reference count on this handle.
485 * @h_err: Field for caller's use to track errors through large fs operations.
486 * @h_sync: Flag for sync-on-close.
487 * @h_jdata: Flag to force data journaling.
488 * @h_reserved: Flag for handle for reserved credits.
489 * @h_aborted: Flag indicating fatal error on handle.
490 * @h_type: For handle statistics.
491 * @h_line_no: For handle statistics.
492 * @h_start_jiffies: Handle Start time.
493 * @h_requested_credits: Holds @h_buffer_credits after handle is started.
494 * @saved_alloc_context: Saved context while transaction is open.
497 /* Docbook can't yet cope with the bit fields, but will leave the documentation
498 * in so it can be fixed later.
501 struct jbd2_journal_handle
504 transaction_t *h_transaction;
505 /* Which journal handle belongs to - used iff h_reserved set */
506 journal_t *h_journal;
509 handle_t *h_rsv_handle;
510 int h_buffer_credits;
514 /* Flags [no locking] */
515 unsigned int h_sync: 1;
516 unsigned int h_jdata: 1;
517 unsigned int h_reserved: 1;
518 unsigned int h_aborted: 1;
519 unsigned int h_type: 8;
520 unsigned int h_line_no: 16;
522 unsigned long h_start_jiffies;
523 unsigned int h_requested_credits;
525 unsigned int saved_alloc_context;
530 * Some stats for checkpoint phase
532 struct transaction_chp_stats_s {
533 unsigned long cs_chp_time;
534 __u32 cs_forced_to_close;
539 /* The transaction_t type is the guts of the journaling mechanism. It
540 * tracks a compound transaction through its various states:
542 * RUNNING: accepting new updates
543 * LOCKED: Updates still running but we don't accept new ones
544 * RUNDOWN: Updates are tidying up but have finished requesting
545 * new buffers to modify (state not used for now)
546 * FLUSH: All updates complete, but we are still writing to disk
547 * COMMIT: All data on disk, writing commit record
548 * FINISHED: We still have to keep the transaction for checkpointing.
550 * The transaction keeps track of all of the buffers modified by a
551 * running transaction, and all of the buffers committed but not yet
552 * flushed to home for finished transactions.
559 * ->jbd_lock_bh_journal_head() (This is "innermost")
562 * ->jbd_lock_bh_state()
564 * jbd_lock_bh_state()
571 * ->j_list_lock (journal_unmap_buffer)
577 /* Pointer to the journal for this transaction. [no locking] */
578 journal_t *t_journal;
580 /* Sequence number for this transaction [no locking] */
584 * Transaction's current state
585 * [no locking - only kjournald2 alters this]
586 * [j_list_lock] guards transition of a transaction into T_FINISHED
587 * state and subsequent call of __jbd2_journal_drop_transaction()
588 * FIXME: needs barriers
589 * KLUDGE: [use j_state_lock]
603 * Where in the log does this transaction's commit start? [no locking]
605 unsigned long t_log_start;
607 /* Number of buffers on the t_buffers list [j_list_lock] */
611 * Doubly-linked circular list of all buffers reserved but not yet
612 * modified by this transaction [j_list_lock]
614 struct journal_head *t_reserved_list;
617 * Doubly-linked circular list of all metadata buffers owned by this
618 * transaction [j_list_lock]
620 struct journal_head *t_buffers;
623 * Doubly-linked circular list of all forget buffers (superseded
624 * buffers which we can un-checkpoint once this transaction commits)
627 struct journal_head *t_forget;
630 * Doubly-linked circular list of all buffers still to be flushed before
631 * this transaction can be checkpointed. [j_list_lock]
633 struct journal_head *t_checkpoint_list;
636 * Doubly-linked circular list of all buffers submitted for IO while
637 * checkpointing. [j_list_lock]
639 struct journal_head *t_checkpoint_io_list;
642 * Doubly-linked circular list of metadata buffers being shadowed by log
643 * IO. The IO buffers on the iobuf list and the shadow buffers on this
644 * list match each other one for one at all times. [j_list_lock]
646 struct journal_head *t_shadow_list;
649 * List of inodes whose data we've modified in data=ordered mode.
652 struct list_head t_inode_list;
655 * Protects info related to handles
657 spinlock_t t_handle_lock;
660 * Longest time some handle had to wait for running transaction
662 unsigned long t_max_wait;
665 * When transaction started
667 unsigned long t_start;
670 * When commit was requested
672 unsigned long t_requested;
675 * Checkpointing stats [j_checkpoint_sem]
677 struct transaction_chp_stats_s t_chp_stats;
680 * Number of outstanding updates running on this transaction
686 * Number of buffers reserved for use by all handles in this transaction
687 * handle but not yet modified. [t_handle_lock]
689 atomic_t t_outstanding_credits;
692 * Forward and backward links for the circular list of all transactions
693 * awaiting checkpoint. [j_list_lock]
695 transaction_t *t_cpnext, *t_cpprev;
698 * When will the transaction expire (become due for commit), in jiffies?
701 unsigned long t_expires;
704 * When this transaction started, in nanoseconds [no locking]
706 ktime_t t_start_time;
709 * How many handles used this transaction? [t_handle_lock]
711 atomic_t t_handle_count;
714 * This transaction is being forced and some process is
715 * waiting for it to finish.
717 unsigned int t_synchronous_commit:1;
719 /* Disk flush needs to be sent to fs partition [no locking] */
720 int t_need_data_flush;
723 * For use by the filesystem to store fs-specific data
724 * structures associated with the transaction
726 struct list_head t_private_list;
729 struct transaction_run_stats_s {
730 unsigned long rs_wait;
731 unsigned long rs_request_delay;
732 unsigned long rs_running;
733 unsigned long rs_locked;
734 unsigned long rs_flushing;
735 unsigned long rs_logging;
737 __u32 rs_handle_count;
739 __u32 rs_blocks_logged;
742 struct transaction_stats_s {
743 unsigned long ts_tid;
744 unsigned long ts_requested;
745 struct transaction_run_stats_s run;
748 static inline unsigned long
749 jbd2_time_diff(unsigned long start, unsigned long end)
754 return end + (MAX_JIFFY_OFFSET - start);
757 #define JBD2_NR_BATCH 64
760 * struct journal_s - The journal_s type is the concrete type associated with
766 * @j_flags: General journaling state flags [j_state_lock]
768 unsigned long j_flags;
773 * Is there an outstanding uncleared error on the journal (from a prior
774 * abort)? [j_state_lock]
779 * @j_sb_buffer: The first part of the superblock buffer.
781 struct buffer_head *j_sb_buffer;
784 * @j_superblock: The second part of the superblock buffer.
786 journal_superblock_t *j_superblock;
789 * @j_format_version: Version of the superblock format.
791 int j_format_version;
794 * @j_state_lock: Protect the various scalars in the journal.
796 rwlock_t j_state_lock;
801 * Number of processes waiting to create a barrier lock [j_state_lock]
806 * @j_barrier: The barrier lock itself.
808 struct mutex j_barrier;
811 * @j_running_transaction:
813 * Transactions: The current running transaction...
814 * [j_state_lock] [caller holding open handle]
816 transaction_t *j_running_transaction;
819 * @j_committing_transaction:
821 * the transaction we are pushing to disk
822 * [j_state_lock] [caller holding open handle]
824 transaction_t *j_committing_transaction;
827 * @j_checkpoint_transactions:
829 * ... and a linked circular list of all transactions waiting for
830 * checkpointing. [j_list_lock]
832 transaction_t *j_checkpoint_transactions;
835 * @j_wait_transaction_locked:
837 * Wait queue for waiting for a locked transaction to start committing,
838 * or for a barrier lock to be released.
840 wait_queue_head_t j_wait_transaction_locked;
843 * @j_wait_done_commit: Wait queue for waiting for commit to complete.
845 wait_queue_head_t j_wait_done_commit;
848 * @j_wait_commit: Wait queue to trigger commit.
850 wait_queue_head_t j_wait_commit;
853 * @j_wait_updates: Wait queue to wait for updates to complete.
855 wait_queue_head_t j_wait_updates;
860 * Wait queue to wait for reserved buffer credits to drop.
862 wait_queue_head_t j_wait_reserved;
865 * @j_checkpoint_mutex:
867 * Semaphore for locking against concurrent checkpoints.
869 struct mutex j_checkpoint_mutex;
874 * List of buffer heads used by the checkpoint routine. This
875 * was moved from jbd2_log_do_checkpoint() to reduce stack
876 * usage. Access to this array is controlled by the
877 * @j_checkpoint_mutex. [j_checkpoint_mutex]
879 struct buffer_head *j_chkpt_bhs[JBD2_NR_BATCH];
884 * Journal head: identifies the first unused block in the journal.
887 unsigned long j_head;
892 * Journal tail: identifies the oldest still-used block in the journal.
895 unsigned long j_tail;
900 * Journal free: how many free blocks are there in the journal?
903 unsigned long j_free;
908 * The block number of the first usable block in the journal
911 unsigned long j_first;
916 * The block number one beyond the last usable block in the journal
919 unsigned long j_last;
922 * @j_dev: Device where we store the journal.
924 struct block_device *j_dev;
927 * @j_blocksize: Block size for the location where we store the journal.
934 * Starting block offset into the device where we store the journal.
936 unsigned long long j_blk_offset;
939 * @j_devname: Journal device name.
941 char j_devname[BDEVNAME_SIZE+24];
946 * Device which holds the client fs. For internal journal this will be
949 struct block_device *j_fs_dev;
952 * @j_maxlen: Total maximum capacity of the journal region on disk.
954 unsigned int j_maxlen;
957 * @j_reserved_credits:
959 * Number of buffers reserved from the running transaction.
961 atomic_t j_reserved_credits;
964 * @j_list_lock: Protects the buffer lists and internal buffer state.
966 spinlock_t j_list_lock;
971 * Optional inode where we store the journal. If present, all
972 * journal block numbers are mapped into this inode via bmap().
974 struct inode *j_inode;
979 * Sequence number of the oldest transaction in the log [j_state_lock]
981 tid_t j_tail_sequence;
984 * @j_transaction_sequence:
986 * Sequence number of the next transaction to grant [j_state_lock]
988 tid_t j_transaction_sequence;
991 * @j_commit_sequence:
993 * Sequence number of the most recently committed transaction
996 tid_t j_commit_sequence;
1001 * Sequence number of the most recent transaction wanting commit
1004 tid_t j_commit_request;
1009 * Journal uuid: identifies the object (filesystem, LVM volume etc)
1010 * backed by this journal. This will eventually be replaced by an array
1011 * of uuids, allowing us to index multiple devices within a single
1012 * journal and to perform atomic updates across them.
1017 * @j_task: Pointer to the current commit thread for this journal.
1019 struct task_struct *j_task;
1022 * @j_max_transaction_buffers:
1024 * Maximum number of metadata buffers to allow in a single compound
1025 * commit transaction.
1027 int j_max_transaction_buffers;
1030 * @j_commit_interval:
1032 * What is the maximum transaction lifetime before we begin a commit?
1034 unsigned long j_commit_interval;
1037 * @j_commit_timer: The timer used to wakeup the commit thread.
1039 struct timer_list j_commit_timer;
1042 * @j_revoke_lock: Protect the revoke table.
1044 spinlock_t j_revoke_lock;
1049 * The revoke table - maintains the list of revoked blocks in the
1050 * current transaction.
1052 struct jbd2_revoke_table_s *j_revoke;
1055 * @j_revoke_table: Alternate revoke tables for j_revoke.
1057 struct jbd2_revoke_table_s *j_revoke_table[2];
1060 * @j_wbuf: Array of bhs for jbd2_journal_commit_transaction.
1062 struct buffer_head **j_wbuf;
1067 * Size of @j_wbuf array.
1072 * @j_last_sync_writer:
1074 * The pid of the last person to run a synchronous operation
1075 * through the journal.
1077 pid_t j_last_sync_writer;
1080 * @j_average_commit_time:
1082 * The average amount of time in nanoseconds it takes to commit a
1083 * transaction to disk. [j_state_lock]
1085 u64 j_average_commit_time;
1088 * @j_min_batch_time:
1090 * Minimum time that we should wait for additional filesystem operations
1091 * to get batched into a synchronous handle in microseconds.
1093 u32 j_min_batch_time;
1096 * @j_max_batch_time:
1098 * Maximum time that we should wait for additional filesystem operations
1099 * to get batched into a synchronous handle in microseconds.
1101 u32 j_max_batch_time;
1104 * @j_commit_callback:
1106 * This function is called when a transaction is closed.
1108 void (*j_commit_callback)(journal_t *,
1112 * Journal statistics
1116 * @j_history_lock: Protect the transactions statistics history.
1118 spinlock_t j_history_lock;
1121 * @j_proc_entry: procfs entry for the jbd statistics directory.
1123 struct proc_dir_entry *j_proc_entry;
1126 * @j_stats: Overall statistics.
1128 struct transaction_stats_s j_stats;
1131 * @j_failed_commit: Failed journal commit ID.
1133 unsigned int j_failed_commit;
1138 * An opaque pointer to fs-private information. ext3 puts its
1139 * superblock pointer here.
1146 * Reference to checksum algorithm driver via cryptoapi.
1148 struct crypto_shash *j_chksum_driver;
1153 * Precomputed journal UUID checksum for seeding other checksums.
1157 #ifdef CONFIG_DEBUG_LOCK_ALLOC
1159 * @j_trans_commit_map:
1161 * Lockdep entity to track transaction commit dependencies. Handles
1162 * hold this "lock" for read, when we wait for commit, we acquire the
1163 * "lock" for writing. This matches the properties of jbd2 journalling
1164 * where the running transaction has to wait for all handles to be
1165 * dropped to commit that transaction and also acquiring a handle may
1166 * require transaction commit to finish.
1168 struct lockdep_map j_trans_commit_map;
1172 #define jbd2_might_wait_for_commit(j) \
1174 rwsem_acquire(&j->j_trans_commit_map, 0, 0, _THIS_IP_); \
1175 rwsem_release(&j->j_trans_commit_map, 1, _THIS_IP_); \
1178 /* journal feature predicate functions */
1179 #define JBD2_FEATURE_COMPAT_FUNCS(name, flagname) \
1180 static inline bool jbd2_has_feature_##name(journal_t *j) \
1182 return ((j)->j_format_version >= 2 && \
1183 ((j)->j_superblock->s_feature_compat & \
1184 cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname)) != 0); \
1186 static inline void jbd2_set_feature_##name(journal_t *j) \
1188 (j)->j_superblock->s_feature_compat |= \
1189 cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
1191 static inline void jbd2_clear_feature_##name(journal_t *j) \
1193 (j)->j_superblock->s_feature_compat &= \
1194 ~cpu_to_be32(JBD2_FEATURE_COMPAT_##flagname); \
1197 #define JBD2_FEATURE_RO_COMPAT_FUNCS(name, flagname) \
1198 static inline bool jbd2_has_feature_##name(journal_t *j) \
1200 return ((j)->j_format_version >= 2 && \
1201 ((j)->j_superblock->s_feature_ro_compat & \
1202 cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname)) != 0); \
1204 static inline void jbd2_set_feature_##name(journal_t *j) \
1206 (j)->j_superblock->s_feature_ro_compat |= \
1207 cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
1209 static inline void jbd2_clear_feature_##name(journal_t *j) \
1211 (j)->j_superblock->s_feature_ro_compat &= \
1212 ~cpu_to_be32(JBD2_FEATURE_RO_COMPAT_##flagname); \
1215 #define JBD2_FEATURE_INCOMPAT_FUNCS(name, flagname) \
1216 static inline bool jbd2_has_feature_##name(journal_t *j) \
1218 return ((j)->j_format_version >= 2 && \
1219 ((j)->j_superblock->s_feature_incompat & \
1220 cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname)) != 0); \
1222 static inline void jbd2_set_feature_##name(journal_t *j) \
1224 (j)->j_superblock->s_feature_incompat |= \
1225 cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
1227 static inline void jbd2_clear_feature_##name(journal_t *j) \
1229 (j)->j_superblock->s_feature_incompat &= \
1230 ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_##flagname); \
1233 JBD2_FEATURE_COMPAT_FUNCS(checksum, CHECKSUM)
1235 JBD2_FEATURE_INCOMPAT_FUNCS(revoke, REVOKE)
1236 JBD2_FEATURE_INCOMPAT_FUNCS(64bit, 64BIT)
1237 JBD2_FEATURE_INCOMPAT_FUNCS(async_commit, ASYNC_COMMIT)
1238 JBD2_FEATURE_INCOMPAT_FUNCS(csum2, CSUM_V2)
1239 JBD2_FEATURE_INCOMPAT_FUNCS(csum3, CSUM_V3)
1242 * Journal flag definitions
1244 #define JBD2_UNMOUNT 0x001 /* Journal thread is being destroyed */
1245 #define JBD2_ABORT 0x002 /* Journaling has been aborted for errors. */
1246 #define JBD2_ACK_ERR 0x004 /* The errno in the sb has been acked */
1247 #define JBD2_FLUSHED 0x008 /* The journal superblock has been flushed */
1248 #define JBD2_LOADED 0x010 /* The journal superblock has been loaded */
1249 #define JBD2_BARRIER 0x020 /* Use IDE barriers */
1250 #define JBD2_ABORT_ON_SYNCDATA_ERR 0x040 /* Abort the journal on file
1251 * data write error in ordered
1253 #define JBD2_REC_ERR 0x080 /* The errno in the sb has been recorded */
1256 * Function declarations for the journaling transaction and buffer
1260 /* Filing buffers */
1261 extern void jbd2_journal_unfile_buffer(journal_t *, struct journal_head *);
1262 extern void __jbd2_journal_refile_buffer(struct journal_head *);
1263 extern void jbd2_journal_refile_buffer(journal_t *, struct journal_head *);
1264 extern void __jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
1265 extern void __journal_free_buffer(struct journal_head *bh);
1266 extern void jbd2_journal_file_buffer(struct journal_head *, transaction_t *, int);
1267 extern void __journal_clean_data_list(transaction_t *transaction);
1268 static inline void jbd2_file_log_bh(struct list_head *head, struct buffer_head *bh)
1270 list_add_tail(&bh->b_assoc_buffers, head);
1272 static inline void jbd2_unfile_log_bh(struct buffer_head *bh)
1274 list_del_init(&bh->b_assoc_buffers);
1277 /* Log buffer allocation */
1278 struct buffer_head *jbd2_journal_get_descriptor_buffer(transaction_t *, int);
1279 void jbd2_descriptor_block_csum_set(journal_t *, struct buffer_head *);
1280 int jbd2_journal_next_log_block(journal_t *, unsigned long long *);
1281 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1282 unsigned long *block);
1283 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
1284 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block);
1286 /* Commit management */
1287 extern void jbd2_journal_commit_transaction(journal_t *);
1289 /* Checkpoint list management */
1290 void __jbd2_journal_clean_checkpoint_list(journal_t *journal, bool destroy);
1291 int __jbd2_journal_remove_checkpoint(struct journal_head *);
1292 void jbd2_journal_destroy_checkpoint(journal_t *journal);
1293 void __jbd2_journal_insert_checkpoint(struct journal_head *, transaction_t *);
1300 struct jbd2_buffer_trigger_type {
1302 * Fired a the moment data to write to the journal are known to be
1303 * stable - so either at the moment b_frozen_data is created or just
1304 * before a buffer is written to the journal. mapped_data is a mapped
1305 * buffer that is the frozen data for commit.
1307 void (*t_frozen)(struct jbd2_buffer_trigger_type *type,
1308 struct buffer_head *bh, void *mapped_data,
1312 * Fired during journal abort for dirty buffers that will not be
1315 void (*t_abort)(struct jbd2_buffer_trigger_type *type,
1316 struct buffer_head *bh);
1319 extern void jbd2_buffer_frozen_trigger(struct journal_head *jh,
1321 struct jbd2_buffer_trigger_type *triggers);
1322 extern void jbd2_buffer_abort_trigger(struct journal_head *jh,
1323 struct jbd2_buffer_trigger_type *triggers);
1326 extern int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
1327 struct journal_head *jh_in,
1328 struct buffer_head **bh_out,
1331 /* Transaction locking */
1332 extern void __wait_on_journal (journal_t *);
1334 /* Transaction cache support */
1335 extern void jbd2_journal_destroy_transaction_cache(void);
1336 extern int __init jbd2_journal_init_transaction_cache(void);
1337 extern void jbd2_journal_free_transaction(transaction_t *);
1342 * We need to lock the journal during transaction state changes so that nobody
1343 * ever tries to take a handle on the running transaction while we are in the
1344 * middle of moving it to the commit phase. j_state_lock does this.
1346 * Note that the locking is completely interrupt unsafe. We never touch
1347 * journal structures from interrupts.
1350 static inline handle_t *journal_current_handle(void)
1352 return current->journal_info;
1355 /* The journaling code user interface:
1357 * Create and destroy handles
1358 * Register buffer modifications against the current transaction.
1361 extern handle_t *jbd2_journal_start(journal_t *, int nblocks);
1362 extern handle_t *jbd2__journal_start(journal_t *, int blocks, int rsv_blocks,
1363 gfp_t gfp_mask, unsigned int type,
1364 unsigned int line_no);
1365 extern int jbd2_journal_restart(handle_t *, int nblocks);
1366 extern int jbd2__journal_restart(handle_t *, int nblocks, gfp_t gfp_mask);
1367 extern int jbd2_journal_start_reserved(handle_t *handle,
1368 unsigned int type, unsigned int line_no);
1369 extern void jbd2_journal_free_reserved(handle_t *handle);
1370 extern int jbd2_journal_extend (handle_t *, int nblocks);
1371 extern int jbd2_journal_get_write_access(handle_t *, struct buffer_head *);
1372 extern int jbd2_journal_get_create_access (handle_t *, struct buffer_head *);
1373 extern int jbd2_journal_get_undo_access(handle_t *, struct buffer_head *);
1374 void jbd2_journal_set_triggers(struct buffer_head *,
1375 struct jbd2_buffer_trigger_type *type);
1376 extern int jbd2_journal_dirty_metadata (handle_t *, struct buffer_head *);
1377 extern int jbd2_journal_forget (handle_t *, struct buffer_head *);
1378 extern void journal_sync_buffer (struct buffer_head *);
1379 extern int jbd2_journal_invalidatepage(journal_t *,
1380 struct page *, unsigned int, unsigned int);
1381 extern int jbd2_journal_try_to_free_buffers(journal_t *, struct page *, gfp_t);
1382 extern int jbd2_journal_stop(handle_t *);
1383 extern int jbd2_journal_flush (journal_t *);
1384 extern void jbd2_journal_lock_updates (journal_t *);
1385 extern void jbd2_journal_unlock_updates (journal_t *);
1387 extern journal_t * jbd2_journal_init_dev(struct block_device *bdev,
1388 struct block_device *fs_dev,
1389 unsigned long long start, int len, int bsize);
1390 extern journal_t * jbd2_journal_init_inode (struct inode *);
1391 extern int jbd2_journal_update_format (journal_t *);
1392 extern int jbd2_journal_check_used_features
1393 (journal_t *, unsigned long, unsigned long, unsigned long);
1394 extern int jbd2_journal_check_available_features
1395 (journal_t *, unsigned long, unsigned long, unsigned long);
1396 extern int jbd2_journal_set_features
1397 (journal_t *, unsigned long, unsigned long, unsigned long);
1398 extern void jbd2_journal_clear_features
1399 (journal_t *, unsigned long, unsigned long, unsigned long);
1400 extern int jbd2_journal_load (journal_t *journal);
1401 extern int jbd2_journal_destroy (journal_t *);
1402 extern int jbd2_journal_recover (journal_t *journal);
1403 extern int jbd2_journal_wipe (journal_t *, int);
1404 extern int jbd2_journal_skip_recovery (journal_t *);
1405 extern void jbd2_journal_update_sb_errno(journal_t *);
1406 extern int jbd2_journal_update_sb_log_tail (journal_t *, tid_t,
1407 unsigned long, int);
1408 extern void __jbd2_journal_abort_hard (journal_t *);
1409 extern void jbd2_journal_abort (journal_t *, int);
1410 extern int jbd2_journal_errno (journal_t *);
1411 extern void jbd2_journal_ack_err (journal_t *);
1412 extern int jbd2_journal_clear_err (journal_t *);
1413 extern int jbd2_journal_bmap(journal_t *, unsigned long, unsigned long long *);
1414 extern int jbd2_journal_force_commit(journal_t *);
1415 extern int jbd2_journal_force_commit_nested(journal_t *);
1416 extern int jbd2_journal_inode_add_write(handle_t *handle, struct jbd2_inode *inode);
1417 extern int jbd2_journal_inode_add_wait(handle_t *handle, struct jbd2_inode *inode);
1418 extern int jbd2_journal_inode_ranged_write(handle_t *handle,
1419 struct jbd2_inode *inode, loff_t start_byte,
1421 extern int jbd2_journal_inode_ranged_wait(handle_t *handle,
1422 struct jbd2_inode *inode, loff_t start_byte,
1424 extern int jbd2_journal_begin_ordered_truncate(journal_t *journal,
1425 struct jbd2_inode *inode, loff_t new_size);
1426 extern void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode);
1427 extern void jbd2_journal_release_jbd_inode(journal_t *journal, struct jbd2_inode *jinode);
1430 * journal_head management
1432 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh);
1433 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh);
1434 void jbd2_journal_put_journal_head(struct journal_head *jh);
1439 extern struct kmem_cache *jbd2_handle_cache;
1441 static inline handle_t *jbd2_alloc_handle(gfp_t gfp_flags)
1443 return kmem_cache_zalloc(jbd2_handle_cache, gfp_flags);
1446 static inline void jbd2_free_handle(handle_t *handle)
1448 kmem_cache_free(jbd2_handle_cache, handle);
1452 * jbd2_inode management (optional, for those file systems that want to use
1453 * dynamically allocated jbd2_inode structures)
1455 extern struct kmem_cache *jbd2_inode_cache;
1457 static inline struct jbd2_inode *jbd2_alloc_inode(gfp_t gfp_flags)
1459 return kmem_cache_alloc(jbd2_inode_cache, gfp_flags);
1462 static inline void jbd2_free_inode(struct jbd2_inode *jinode)
1464 kmem_cache_free(jbd2_inode_cache, jinode);
1467 /* Primary revoke support */
1468 #define JOURNAL_REVOKE_DEFAULT_HASH 256
1469 extern int jbd2_journal_init_revoke(journal_t *, int);
1470 extern void jbd2_journal_destroy_revoke_record_cache(void);
1471 extern void jbd2_journal_destroy_revoke_table_cache(void);
1472 extern int __init jbd2_journal_init_revoke_record_cache(void);
1473 extern int __init jbd2_journal_init_revoke_table_cache(void);
1475 extern void jbd2_journal_destroy_revoke(journal_t *);
1476 extern int jbd2_journal_revoke (handle_t *, unsigned long long, struct buffer_head *);
1477 extern int jbd2_journal_cancel_revoke(handle_t *, struct journal_head *);
1478 extern void jbd2_journal_write_revoke_records(transaction_t *transaction,
1479 struct list_head *log_bufs);
1481 /* Recovery revoke support */
1482 extern int jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t);
1483 extern int jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);
1484 extern void jbd2_journal_clear_revoke(journal_t *);
1485 extern void jbd2_journal_switch_revoke_table(journal_t *journal);
1486 extern void jbd2_clear_buffer_revoked_flags(journal_t *journal);
1489 * The log thread user interface:
1491 * Request space in the current transaction, and force transaction commit
1492 * transitions on demand.
1495 int jbd2_log_start_commit(journal_t *journal, tid_t tid);
1496 int __jbd2_log_start_commit(journal_t *journal, tid_t tid);
1497 int jbd2_journal_start_commit(journal_t *journal, tid_t *tid);
1498 int jbd2_log_wait_commit(journal_t *journal, tid_t tid);
1499 int jbd2_transaction_committed(journal_t *journal, tid_t tid);
1500 int jbd2_complete_transaction(journal_t *journal, tid_t tid);
1501 int jbd2_log_do_checkpoint(journal_t *journal);
1502 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid);
1504 void __jbd2_log_wait_for_space(journal_t *journal);
1505 extern void __jbd2_journal_drop_transaction(journal_t *, transaction_t *);
1506 extern int jbd2_cleanup_journal_tail(journal_t *);
1511 * Simple test wrapper function to test the JBD2_ABORT state flag. This
1512 * bit, when set, indicates that we have had a fatal error somewhere,
1513 * either inside the journaling layer or indicated to us by the client
1514 * (eg. ext3), and that we and should not commit any further
1518 static inline int is_journal_aborted(journal_t *journal)
1520 return journal->j_flags & JBD2_ABORT;
1523 static inline int is_handle_aborted(handle_t *handle)
1525 if (handle->h_aborted || !handle->h_transaction)
1527 return is_journal_aborted(handle->h_transaction->t_journal);
1530 static inline void jbd2_journal_abort_handle(handle_t *handle)
1532 handle->h_aborted = 1;
1535 #endif /* __KERNEL__ */
1537 /* Comparison functions for transaction IDs: perform comparisons using
1538 * modulo arithmetic so that they work over sequence number wraps. */
1540 static inline int tid_gt(tid_t x, tid_t y)
1542 int difference = (x - y);
1543 return (difference > 0);
1546 static inline int tid_geq(tid_t x, tid_t y)
1548 int difference = (x - y);
1549 return (difference >= 0);
1552 extern int jbd2_journal_blocks_per_page(struct inode *inode);
1553 extern size_t journal_tag_bytes(journal_t *journal);
1555 static inline bool jbd2_journal_has_csum_v2or3_feature(journal_t *j)
1557 return jbd2_has_feature_csum2(j) || jbd2_has_feature_csum3(j);
1560 static inline int jbd2_journal_has_csum_v2or3(journal_t *journal)
1562 WARN_ON_ONCE(jbd2_journal_has_csum_v2or3_feature(journal) &&
1563 journal->j_chksum_driver == NULL);
1565 return journal->j_chksum_driver != NULL;
1569 * We reserve t_outstanding_credits >> JBD2_CONTROL_BLOCKS_SHIFT for
1570 * transaction control blocks.
1572 #define JBD2_CONTROL_BLOCKS_SHIFT 5
1575 * Return the minimum number of blocks which must be free in the journal
1576 * before a new transaction may be started. Must be called under j_state_lock.
1578 static inline int jbd2_space_needed(journal_t *journal)
1580 int nblocks = journal->j_max_transaction_buffers;
1581 return nblocks + (nblocks >> JBD2_CONTROL_BLOCKS_SHIFT);
1585 * Return number of free blocks in the log. Must be called under j_state_lock.
1587 static inline unsigned long jbd2_log_space_left(journal_t *journal)
1589 /* Allow for rounding errors */
1590 long free = journal->j_free - 32;
1592 if (journal->j_committing_transaction) {
1593 unsigned long committing = atomic_read(&journal->
1594 j_committing_transaction->t_outstanding_credits);
1596 /* Transaction + control blocks */
1597 free -= committing + (committing >> JBD2_CONTROL_BLOCKS_SHIFT);
1599 return max_t(long, free, 0);
1603 * Definitions which augment the buffer_head layer
1606 /* journaling buffer types */
1607 #define BJ_None 0 /* Not journaled */
1608 #define BJ_Metadata 1 /* Normal journaled metadata */
1609 #define BJ_Forget 2 /* Buffer superseded by this transaction */
1610 #define BJ_Shadow 3 /* Buffer contents being shadowed to the log */
1611 #define BJ_Reserved 4 /* Buffer is reserved for access by journal */
1614 extern int jbd_blocks_per_page(struct inode *inode);
1616 /* JBD uses a CRC32 checksum */
1617 #define JBD_MAX_CHECKSUM_SIZE 4
1619 static inline u32 jbd2_chksum(journal_t *journal, u32 crc,
1620 const void *address, unsigned int length)
1623 struct shash_desc shash;
1624 char ctx[JBD_MAX_CHECKSUM_SIZE];
1628 BUG_ON(crypto_shash_descsize(journal->j_chksum_driver) >
1629 JBD_MAX_CHECKSUM_SIZE);
1631 desc.shash.tfm = journal->j_chksum_driver;
1632 desc.shash.flags = 0;
1633 *(u32 *)desc.ctx = crc;
1635 err = crypto_shash_update(&desc.shash, address, length);
1638 return *(u32 *)desc.ctx;
1641 /* Return most recent uncommitted transaction */
1642 static inline tid_t jbd2_get_latest_transaction(journal_t *journal)
1646 read_lock(&journal->j_state_lock);
1647 tid = journal->j_commit_request;
1648 if (journal->j_running_transaction)
1649 tid = journal->j_running_transaction->t_tid;
1650 read_unlock(&journal->j_state_lock);
1656 #define buffer_trace_init(bh) do {} while (0)
1657 #define print_buffer_fields(bh) do {} while (0)
1658 #define print_buffer_trace(bh) do {} while (0)
1659 #define BUFFER_TRACE(bh, info) do {} while (0)
1660 #define BUFFER_TRACE2(bh, bh2, info) do {} while (0)
1661 #define JBUFFER_TRACE(jh, info) do {} while (0)
1663 #endif /* __KERNEL__ */
1665 #define EFSBADCRC EBADMSG /* Bad CRC detected */
1666 #define EFSCORRUPTED EUCLEAN /* Filesystem is corrupted */
1668 #endif /* _LINUX_JBD2_H */