2 * linux/fs/jbd2/journal.c
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 * Copyright 1998 Red Hat corp --- 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 * Generic filesystem journal-writing code; part of the ext2fs
15 * This file manages journals: areas of disk reserved for logging
16 * transactional updates. This includes the kernel journaling thread
17 * which is responsible for scheduling updates to the log.
19 * We do not actually manage the physical storage of the journal in this
20 * file: that is left to a per-journal policy function, which allows us
21 * to store the journal within a filesystem-specified area for ext2
22 * journaling (ext2 can use a reserved inode for storing the log).
25 #include <linux/module.h>
26 #include <linux/time.h>
28 #include <linux/jbd2.h>
29 #include <linux/errno.h>
30 #include <linux/slab.h>
31 #include <linux/init.h>
33 #include <linux/freezer.h>
34 #include <linux/pagemap.h>
35 #include <linux/kthread.h>
36 #include <linux/poison.h>
37 #include <linux/proc_fs.h>
38 #include <linux/debugfs.h>
39 #include <linux/seq_file.h>
40 #include <linux/math64.h>
41 #include <linux/hash.h>
42 #include <linux/log2.h>
43 #include <linux/vmalloc.h>
44 #include <linux/backing-dev.h>
45 #include <linux/bitops.h>
46 #include <linux/ratelimit.h>
48 #define CREATE_TRACE_POINTS
49 #include <trace/events/jbd2.h>
51 #include <asm/uaccess.h>
53 #include <asm/system.h>
55 EXPORT_SYMBOL(jbd2_journal_extend);
56 EXPORT_SYMBOL(jbd2_journal_stop);
57 EXPORT_SYMBOL(jbd2_journal_lock_updates);
58 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
59 EXPORT_SYMBOL(jbd2_journal_get_write_access);
60 EXPORT_SYMBOL(jbd2_journal_get_create_access);
61 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
62 EXPORT_SYMBOL(jbd2_journal_set_triggers);
63 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
64 EXPORT_SYMBOL(jbd2_journal_release_buffer);
65 EXPORT_SYMBOL(jbd2_journal_forget);
67 EXPORT_SYMBOL(journal_sync_buffer);
69 EXPORT_SYMBOL(jbd2_journal_flush);
70 EXPORT_SYMBOL(jbd2_journal_revoke);
72 EXPORT_SYMBOL(jbd2_journal_init_dev);
73 EXPORT_SYMBOL(jbd2_journal_init_inode);
74 EXPORT_SYMBOL(jbd2_journal_update_format);
75 EXPORT_SYMBOL(jbd2_journal_check_used_features);
76 EXPORT_SYMBOL(jbd2_journal_check_available_features);
77 EXPORT_SYMBOL(jbd2_journal_set_features);
78 EXPORT_SYMBOL(jbd2_journal_load);
79 EXPORT_SYMBOL(jbd2_journal_destroy);
80 EXPORT_SYMBOL(jbd2_journal_abort);
81 EXPORT_SYMBOL(jbd2_journal_errno);
82 EXPORT_SYMBOL(jbd2_journal_ack_err);
83 EXPORT_SYMBOL(jbd2_journal_clear_err);
84 EXPORT_SYMBOL(jbd2_log_wait_commit);
85 EXPORT_SYMBOL(jbd2_log_start_commit);
86 EXPORT_SYMBOL(jbd2_journal_start_commit);
87 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
88 EXPORT_SYMBOL(jbd2_journal_wipe);
89 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
90 EXPORT_SYMBOL(jbd2_journal_invalidatepage);
91 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
92 EXPORT_SYMBOL(jbd2_journal_force_commit);
93 EXPORT_SYMBOL(jbd2_journal_file_inode);
94 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
95 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
96 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
97 EXPORT_SYMBOL(jbd2_inode_cache);
99 static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *);
100 static void __journal_abort_soft (journal_t *journal, int errno);
101 static int jbd2_journal_create_slab(size_t slab_size);
104 * Helper function used to manage commit timeouts
107 static void commit_timeout(unsigned long __data)
109 struct task_struct * p = (struct task_struct *) __data;
115 * kjournald2: The main thread function used to manage a logging device
118 * This kernel thread is responsible for two things:
120 * 1) COMMIT: Every so often we need to commit the current state of the
121 * filesystem to disk. The journal thread is responsible for writing
122 * all of the metadata buffers to disk.
124 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
125 * of the data in that part of the log has been rewritten elsewhere on
126 * the disk. Flushing these old buffers to reclaim space in the log is
127 * known as checkpointing, and this thread is responsible for that job.
130 static int kjournald2(void *arg)
132 journal_t *journal = arg;
133 transaction_t *transaction;
136 * Set up an interval timer which can be used to trigger a commit wakeup
137 * after the commit interval expires
139 setup_timer(&journal->j_commit_timer, commit_timeout,
140 (unsigned long)current);
142 /* Record that the journal thread is running */
143 journal->j_task = current;
144 wake_up(&journal->j_wait_done_commit);
147 * And now, wait forever for commit wakeup events.
149 write_lock(&journal->j_state_lock);
152 if (journal->j_flags & JBD2_UNMOUNT)
155 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
156 journal->j_commit_sequence, journal->j_commit_request);
158 if (journal->j_commit_sequence != journal->j_commit_request) {
159 jbd_debug(1, "OK, requests differ\n");
160 write_unlock(&journal->j_state_lock);
161 del_timer_sync(&journal->j_commit_timer);
162 jbd2_journal_commit_transaction(journal);
163 write_lock(&journal->j_state_lock);
167 wake_up(&journal->j_wait_done_commit);
168 if (freezing(current)) {
170 * The simpler the better. Flushing journal isn't a
171 * good idea, because that depends on threads that may
172 * be already stopped.
174 jbd_debug(1, "Now suspending kjournald2\n");
175 write_unlock(&journal->j_state_lock);
177 write_lock(&journal->j_state_lock);
180 * We assume on resume that commits are already there,
184 int should_sleep = 1;
186 prepare_to_wait(&journal->j_wait_commit, &wait,
188 if (journal->j_commit_sequence != journal->j_commit_request)
190 transaction = journal->j_running_transaction;
191 if (transaction && time_after_eq(jiffies,
192 transaction->t_expires))
194 if (journal->j_flags & JBD2_UNMOUNT)
197 write_unlock(&journal->j_state_lock);
199 write_lock(&journal->j_state_lock);
201 finish_wait(&journal->j_wait_commit, &wait);
204 jbd_debug(1, "kjournald2 wakes\n");
207 * Were we woken up by a commit wakeup event?
209 transaction = journal->j_running_transaction;
210 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
211 journal->j_commit_request = transaction->t_tid;
212 jbd_debug(1, "woke because of timeout\n");
217 write_unlock(&journal->j_state_lock);
218 del_timer_sync(&journal->j_commit_timer);
219 journal->j_task = NULL;
220 wake_up(&journal->j_wait_done_commit);
221 jbd_debug(1, "Journal thread exiting.\n");
225 static int jbd2_journal_start_thread(journal_t *journal)
227 struct task_struct *t;
229 t = kthread_run(kjournald2, journal, "jbd2/%s",
234 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
238 static void journal_kill_thread(journal_t *journal)
240 write_lock(&journal->j_state_lock);
241 journal->j_flags |= JBD2_UNMOUNT;
243 while (journal->j_task) {
244 wake_up(&journal->j_wait_commit);
245 write_unlock(&journal->j_state_lock);
246 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
247 write_lock(&journal->j_state_lock);
249 write_unlock(&journal->j_state_lock);
253 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
255 * Writes a metadata buffer to a given disk block. The actual IO is not
256 * performed but a new buffer_head is constructed which labels the data
257 * to be written with the correct destination disk block.
259 * Any magic-number escaping which needs to be done will cause a
260 * copy-out here. If the buffer happens to start with the
261 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
262 * magic number is only written to the log for descripter blocks. In
263 * this case, we copy the data and replace the first word with 0, and we
264 * return a result code which indicates that this buffer needs to be
265 * marked as an escaped buffer in the corresponding log descriptor
266 * block. The missing word can then be restored when the block is read
269 * If the source buffer has already been modified by a new transaction
270 * since we took the last commit snapshot, we use the frozen copy of
271 * that data for IO. If we end up using the existing buffer_head's data
272 * for the write, then we *have* to lock the buffer to prevent anyone
273 * else from using and possibly modifying it while the IO is in
276 * The function returns a pointer to the buffer_heads to be used for IO.
278 * We assume that the journal has already been locked in this function.
285 * Bit 0 set == escape performed on the data
286 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
289 int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
290 struct journal_head *jh_in,
291 struct journal_head **jh_out,
292 unsigned long long blocknr)
294 int need_copy_out = 0;
295 int done_copy_out = 0;
298 struct buffer_head *new_bh;
299 struct journal_head *new_jh;
300 struct page *new_page;
301 unsigned int new_offset;
302 struct buffer_head *bh_in = jh2bh(jh_in);
303 journal_t *journal = transaction->t_journal;
306 * The buffer really shouldn't be locked: only the current committing
307 * transaction is allowed to write it, so nobody else is allowed
310 * akpm: except if we're journalling data, and write() output is
311 * also part of a shared mapping, and another thread has
312 * decided to launch a writepage() against this buffer.
314 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
317 new_bh = alloc_buffer_head(GFP_NOFS);
320 * Failure is not an option, but __GFP_NOFAIL is going
321 * away; so we retry ourselves here.
323 congestion_wait(BLK_RW_ASYNC, HZ/50);
327 /* keep subsequent assertions sane */
329 init_buffer(new_bh, NULL, NULL);
330 atomic_set(&new_bh->b_count, 1);
331 new_jh = jbd2_journal_add_journal_head(new_bh); /* This sleeps */
334 * If a new transaction has already done a buffer copy-out, then
335 * we use that version of the data for the commit.
337 jbd_lock_bh_state(bh_in);
339 if (jh_in->b_frozen_data) {
341 new_page = virt_to_page(jh_in->b_frozen_data);
342 new_offset = offset_in_page(jh_in->b_frozen_data);
344 new_page = jh2bh(jh_in)->b_page;
345 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
348 mapped_data = kmap_atomic(new_page, KM_USER0);
350 * Fire data frozen trigger if data already wasn't frozen. Do this
351 * before checking for escaping, as the trigger may modify the magic
352 * offset. If a copy-out happens afterwards, it will have the correct
353 * data in the buffer.
356 jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
362 if (*((__be32 *)(mapped_data + new_offset)) ==
363 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
367 kunmap_atomic(mapped_data, KM_USER0);
370 * Do we need to do a data copy?
372 if (need_copy_out && !done_copy_out) {
375 jbd_unlock_bh_state(bh_in);
376 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
378 jbd2_journal_put_journal_head(new_jh);
381 jbd_lock_bh_state(bh_in);
382 if (jh_in->b_frozen_data) {
383 jbd2_free(tmp, bh_in->b_size);
387 jh_in->b_frozen_data = tmp;
388 mapped_data = kmap_atomic(new_page, KM_USER0);
389 memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size);
390 kunmap_atomic(mapped_data, KM_USER0);
392 new_page = virt_to_page(tmp);
393 new_offset = offset_in_page(tmp);
397 * This isn't strictly necessary, as we're using frozen
398 * data for the escaping, but it keeps consistency with
399 * b_frozen_data usage.
401 jh_in->b_frozen_triggers = jh_in->b_triggers;
405 * Did we need to do an escaping? Now we've done all the
406 * copying, we can finally do so.
409 mapped_data = kmap_atomic(new_page, KM_USER0);
410 *((unsigned int *)(mapped_data + new_offset)) = 0;
411 kunmap_atomic(mapped_data, KM_USER0);
414 set_bh_page(new_bh, new_page, new_offset);
415 new_jh->b_transaction = NULL;
416 new_bh->b_size = jh2bh(jh_in)->b_size;
417 new_bh->b_bdev = transaction->t_journal->j_dev;
418 new_bh->b_blocknr = blocknr;
419 set_buffer_mapped(new_bh);
420 set_buffer_dirty(new_bh);
425 * The to-be-written buffer needs to get moved to the io queue,
426 * and the original buffer whose contents we are shadowing or
427 * copying is moved to the transaction's shadow queue.
429 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
430 spin_lock(&journal->j_list_lock);
431 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
432 spin_unlock(&journal->j_list_lock);
433 jbd_unlock_bh_state(bh_in);
435 JBUFFER_TRACE(new_jh, "file as BJ_IO");
436 jbd2_journal_file_buffer(new_jh, transaction, BJ_IO);
438 return do_escape | (done_copy_out << 1);
442 * Allocation code for the journal file. Manage the space left in the
443 * journal, so that we can begin checkpointing when appropriate.
447 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
449 * Called with the journal already locked.
451 * Called under j_state_lock
454 int __jbd2_log_space_left(journal_t *journal)
456 int left = journal->j_free;
458 /* assert_spin_locked(&journal->j_state_lock); */
461 * Be pessimistic here about the number of those free blocks which
462 * might be required for log descriptor control blocks.
465 #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
467 left -= MIN_LOG_RESERVED_BLOCKS;
476 * Called with j_state_lock locked for writing.
477 * Returns true if a transaction commit was started.
479 int __jbd2_log_start_commit(journal_t *journal, tid_t target)
482 * The only transaction we can possibly wait upon is the
483 * currently running transaction (if it exists). Otherwise,
484 * the target tid must be an old one.
486 if (journal->j_running_transaction &&
487 journal->j_running_transaction->t_tid == target) {
489 * We want a new commit: OK, mark the request and wakeup the
490 * commit thread. We do _not_ do the commit ourselves.
493 journal->j_commit_request = target;
494 jbd_debug(1, "JBD2: requesting commit %d/%d\n",
495 journal->j_commit_request,
496 journal->j_commit_sequence);
497 wake_up(&journal->j_wait_commit);
499 } else if (!tid_geq(journal->j_commit_request, target))
500 /* This should never happen, but if it does, preserve
501 the evidence before kjournald goes into a loop and
502 increments j_commit_sequence beyond all recognition. */
503 WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
504 journal->j_commit_request,
505 journal->j_commit_sequence,
506 target, journal->j_running_transaction ?
507 journal->j_running_transaction->t_tid : 0);
511 int jbd2_log_start_commit(journal_t *journal, tid_t tid)
515 write_lock(&journal->j_state_lock);
516 ret = __jbd2_log_start_commit(journal, tid);
517 write_unlock(&journal->j_state_lock);
522 * Force and wait upon a commit if the calling process is not within
523 * transaction. This is used for forcing out undo-protected data which contains
524 * bitmaps, when the fs is running out of space.
526 * We can only force the running transaction if we don't have an active handle;
527 * otherwise, we will deadlock.
529 * Returns true if a transaction was started.
531 int jbd2_journal_force_commit_nested(journal_t *journal)
533 transaction_t *transaction = NULL;
535 int need_to_start = 0;
537 read_lock(&journal->j_state_lock);
538 if (journal->j_running_transaction && !current->journal_info) {
539 transaction = journal->j_running_transaction;
540 if (!tid_geq(journal->j_commit_request, transaction->t_tid))
542 } else if (journal->j_committing_transaction)
543 transaction = journal->j_committing_transaction;
546 read_unlock(&journal->j_state_lock);
547 return 0; /* Nothing to retry */
550 tid = transaction->t_tid;
551 read_unlock(&journal->j_state_lock);
553 jbd2_log_start_commit(journal, tid);
554 jbd2_log_wait_commit(journal, tid);
559 * Start a commit of the current running transaction (if any). Returns true
560 * if a transaction is going to be committed (or is currently already
561 * committing), and fills its tid in at *ptid
563 int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
567 write_lock(&journal->j_state_lock);
568 if (journal->j_running_transaction) {
569 tid_t tid = journal->j_running_transaction->t_tid;
571 __jbd2_log_start_commit(journal, tid);
572 /* There's a running transaction and we've just made sure
573 * it's commit has been scheduled. */
577 } else if (journal->j_committing_transaction) {
579 * If ext3_write_super() recently started a commit, then we
580 * have to wait for completion of that transaction
583 *ptid = journal->j_committing_transaction->t_tid;
586 write_unlock(&journal->j_state_lock);
591 * Return 1 if a given transaction has not yet sent barrier request
592 * connected with a transaction commit. If 0 is returned, transaction
593 * may or may not have sent the barrier. Used to avoid sending barrier
594 * twice in common cases.
596 int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
599 transaction_t *commit_trans;
601 if (!(journal->j_flags & JBD2_BARRIER))
603 read_lock(&journal->j_state_lock);
604 /* Transaction already committed? */
605 if (tid_geq(journal->j_commit_sequence, tid))
607 commit_trans = journal->j_committing_transaction;
608 if (!commit_trans || commit_trans->t_tid != tid) {
613 * Transaction is being committed and we already proceeded to
614 * submitting a flush to fs partition?
616 if (journal->j_fs_dev != journal->j_dev) {
617 if (!commit_trans->t_need_data_flush ||
618 commit_trans->t_state >= T_COMMIT_DFLUSH)
621 if (commit_trans->t_state >= T_COMMIT_JFLUSH)
626 read_unlock(&journal->j_state_lock);
629 EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
632 * Wait for a specified commit to complete.
633 * The caller may not hold the journal lock.
635 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
639 read_lock(&journal->j_state_lock);
640 #ifdef CONFIG_JBD2_DEBUG
641 if (!tid_geq(journal->j_commit_request, tid)) {
643 "%s: error: j_commit_request=%d, tid=%d\n",
644 __func__, journal->j_commit_request, tid);
647 while (tid_gt(tid, journal->j_commit_sequence)) {
648 jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
649 tid, journal->j_commit_sequence);
650 wake_up(&journal->j_wait_commit);
651 read_unlock(&journal->j_state_lock);
652 wait_event(journal->j_wait_done_commit,
653 !tid_gt(tid, journal->j_commit_sequence));
654 read_lock(&journal->j_state_lock);
656 read_unlock(&journal->j_state_lock);
658 if (unlikely(is_journal_aborted(journal))) {
659 printk(KERN_EMERG "journal commit I/O error\n");
666 * When this function returns the transaction corresponding to tid
667 * will be completed. If the transaction has currently running, start
668 * committing that transaction before waiting for it to complete. If
669 * the transaction id is stale, it is by definition already completed,
670 * so just return SUCCESS.
672 int jbd2_complete_transaction(journal_t *journal, tid_t tid)
674 int need_to_wait = 1;
676 read_lock(&journal->j_state_lock);
677 if (journal->j_running_transaction &&
678 journal->j_running_transaction->t_tid == tid) {
679 if (journal->j_commit_request != tid) {
680 /* transaction not yet started, so request it */
681 read_unlock(&journal->j_state_lock);
682 jbd2_log_start_commit(journal, tid);
685 } else if (!(journal->j_committing_transaction &&
686 journal->j_committing_transaction->t_tid == tid))
688 read_unlock(&journal->j_state_lock);
692 return jbd2_log_wait_commit(journal, tid);
694 EXPORT_SYMBOL(jbd2_complete_transaction);
697 * Log buffer allocation routines:
700 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
702 unsigned long blocknr;
704 write_lock(&journal->j_state_lock);
705 J_ASSERT(journal->j_free > 1);
707 blocknr = journal->j_head;
710 if (journal->j_head == journal->j_last)
711 journal->j_head = journal->j_first;
712 write_unlock(&journal->j_state_lock);
713 return jbd2_journal_bmap(journal, blocknr, retp);
717 * Conversion of logical to physical block numbers for the journal
719 * On external journals the journal blocks are identity-mapped, so
720 * this is a no-op. If needed, we can use j_blk_offset - everything is
723 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
724 unsigned long long *retp)
727 unsigned long long ret;
729 if (journal->j_inode) {
730 ret = bmap(journal->j_inode, blocknr);
734 printk(KERN_ALERT "%s: journal block not found "
735 "at offset %lu on %s\n",
736 __func__, blocknr, journal->j_devname);
738 __journal_abort_soft(journal, err);
741 *retp = blocknr; /* +journal->j_blk_offset */
747 * We play buffer_head aliasing tricks to write data/metadata blocks to
748 * the journal without copying their contents, but for journal
749 * descriptor blocks we do need to generate bona fide buffers.
751 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
752 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
753 * But we don't bother doing that, so there will be coherency problems with
754 * mmaps of blockdevs which hold live JBD-controlled filesystems.
756 struct journal_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
758 struct buffer_head *bh;
759 unsigned long long blocknr;
762 err = jbd2_journal_next_log_block(journal, &blocknr);
767 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
771 memset(bh->b_data, 0, journal->j_blocksize);
772 set_buffer_uptodate(bh);
774 BUFFER_TRACE(bh, "return this buffer");
775 return jbd2_journal_add_journal_head(bh);
778 struct jbd2_stats_proc_session {
780 struct transaction_stats_s *stats;
785 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
787 return *pos ? NULL : SEQ_START_TOKEN;
790 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
795 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
797 struct jbd2_stats_proc_session *s = seq->private;
799 if (v != SEQ_START_TOKEN)
801 seq_printf(seq, "%lu transaction, each up to %u blocks\n",
803 s->journal->j_max_transaction_buffers);
804 if (s->stats->ts_tid == 0)
806 seq_printf(seq, "average: \n %ums waiting for transaction\n",
807 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
808 seq_printf(seq, " %ums running transaction\n",
809 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
810 seq_printf(seq, " %ums transaction was being locked\n",
811 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
812 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
813 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
814 seq_printf(seq, " %ums logging transaction\n",
815 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
816 seq_printf(seq, " %lluus average transaction commit time\n",
817 div_u64(s->journal->j_average_commit_time, 1000));
818 seq_printf(seq, " %lu handles per transaction\n",
819 s->stats->run.rs_handle_count / s->stats->ts_tid);
820 seq_printf(seq, " %lu blocks per transaction\n",
821 s->stats->run.rs_blocks / s->stats->ts_tid);
822 seq_printf(seq, " %lu logged blocks per transaction\n",
823 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
827 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
831 static const struct seq_operations jbd2_seq_info_ops = {
832 .start = jbd2_seq_info_start,
833 .next = jbd2_seq_info_next,
834 .stop = jbd2_seq_info_stop,
835 .show = jbd2_seq_info_show,
838 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
840 journal_t *journal = PDE(inode)->data;
841 struct jbd2_stats_proc_session *s;
844 s = kmalloc(sizeof(*s), GFP_KERNEL);
847 size = sizeof(struct transaction_stats_s);
848 s->stats = kmalloc(size, GFP_KERNEL);
849 if (s->stats == NULL) {
853 spin_lock(&journal->j_history_lock);
854 memcpy(s->stats, &journal->j_stats, size);
855 s->journal = journal;
856 spin_unlock(&journal->j_history_lock);
858 rc = seq_open(file, &jbd2_seq_info_ops);
860 struct seq_file *m = file->private_data;
870 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
872 struct seq_file *seq = file->private_data;
873 struct jbd2_stats_proc_session *s = seq->private;
876 return seq_release(inode, file);
879 static const struct file_operations jbd2_seq_info_fops = {
880 .owner = THIS_MODULE,
881 .open = jbd2_seq_info_open,
884 .release = jbd2_seq_info_release,
887 static struct proc_dir_entry *proc_jbd2_stats;
889 static void jbd2_stats_proc_init(journal_t *journal)
891 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
892 if (journal->j_proc_entry) {
893 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
894 &jbd2_seq_info_fops, journal);
898 static void jbd2_stats_proc_exit(journal_t *journal)
900 remove_proc_entry("info", journal->j_proc_entry);
901 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
905 * Management for journal control blocks: functions to create and
906 * destroy journal_t structures, and to initialise and read existing
907 * journal blocks from disk. */
909 /* First: create and setup a journal_t object in memory. We initialise
910 * very few fields yet: that has to wait until we have created the
911 * journal structures from from scratch, or loaded them from disk. */
913 static journal_t * journal_init_common (void)
918 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
922 init_waitqueue_head(&journal->j_wait_transaction_locked);
923 init_waitqueue_head(&journal->j_wait_logspace);
924 init_waitqueue_head(&journal->j_wait_done_commit);
925 init_waitqueue_head(&journal->j_wait_checkpoint);
926 init_waitqueue_head(&journal->j_wait_commit);
927 init_waitqueue_head(&journal->j_wait_updates);
928 mutex_init(&journal->j_barrier);
929 mutex_init(&journal->j_checkpoint_mutex);
930 spin_lock_init(&journal->j_revoke_lock);
931 spin_lock_init(&journal->j_list_lock);
932 rwlock_init(&journal->j_state_lock);
934 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
935 journal->j_min_batch_time = 0;
936 journal->j_max_batch_time = 15000; /* 15ms */
938 /* The journal is marked for error until we succeed with recovery! */
939 journal->j_flags = JBD2_ABORT;
941 /* Set up a default-sized revoke table for the new mount. */
942 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
948 spin_lock_init(&journal->j_history_lock);
953 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
955 * Create a journal structure assigned some fixed set of disk blocks to
956 * the journal. We don't actually touch those disk blocks yet, but we
957 * need to set up all of the mapping information to tell the journaling
958 * system where the journal blocks are.
963 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
964 * @bdev: Block device on which to create the journal
965 * @fs_dev: Device which hold journalled filesystem for this journal.
966 * @start: Block nr Start of journal.
967 * @len: Length of the journal in blocks.
968 * @blocksize: blocksize of journalling device
970 * Returns: a newly created journal_t *
972 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
973 * range of blocks on an arbitrary block device.
976 journal_t * jbd2_journal_init_dev(struct block_device *bdev,
977 struct block_device *fs_dev,
978 unsigned long long start, int len, int blocksize)
980 journal_t *journal = journal_init_common();
981 struct buffer_head *bh;
988 /* journal descriptor can store up to n blocks -bzzz */
989 journal->j_blocksize = blocksize;
990 journal->j_dev = bdev;
991 journal->j_fs_dev = fs_dev;
992 journal->j_blk_offset = start;
993 journal->j_maxlen = len;
994 bdevname(journal->j_dev, journal->j_devname);
995 p = journal->j_devname;
996 while ((p = strchr(p, '/')))
998 jbd2_stats_proc_init(journal);
999 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1000 journal->j_wbufsize = n;
1001 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1002 if (!journal->j_wbuf) {
1003 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1008 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
1011 "%s: Cannot get buffer for journal superblock\n",
1015 journal->j_sb_buffer = bh;
1016 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1020 kfree(journal->j_wbuf);
1021 jbd2_stats_proc_exit(journal);
1027 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1028 * @inode: An inode to create the journal in
1030 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1031 * the journal. The inode must exist already, must support bmap() and
1032 * must have all data blocks preallocated.
1034 journal_t * jbd2_journal_init_inode (struct inode *inode)
1036 struct buffer_head *bh;
1037 journal_t *journal = journal_init_common();
1041 unsigned long long blocknr;
1046 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
1047 journal->j_inode = inode;
1048 bdevname(journal->j_dev, journal->j_devname);
1049 p = journal->j_devname;
1050 while ((p = strchr(p, '/')))
1052 p = journal->j_devname + strlen(journal->j_devname);
1053 sprintf(p, "-%lu", journal->j_inode->i_ino);
1055 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
1056 journal, inode->i_sb->s_id, inode->i_ino,
1057 (long long) inode->i_size,
1058 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1060 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
1061 journal->j_blocksize = inode->i_sb->s_blocksize;
1062 jbd2_stats_proc_init(journal);
1064 /* journal descriptor can store up to n blocks -bzzz */
1065 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1066 journal->j_wbufsize = n;
1067 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1068 if (!journal->j_wbuf) {
1069 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1074 err = jbd2_journal_bmap(journal, 0, &blocknr);
1075 /* If that failed, give up */
1077 printk(KERN_ERR "%s: Cannot locate journal superblock\n",
1082 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
1085 "%s: Cannot get buffer for journal superblock\n",
1089 journal->j_sb_buffer = bh;
1090 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1094 kfree(journal->j_wbuf);
1095 jbd2_stats_proc_exit(journal);
1101 * If the journal init or create aborts, we need to mark the journal
1102 * superblock as being NULL to prevent the journal destroy from writing
1103 * back a bogus superblock.
1105 static void journal_fail_superblock (journal_t *journal)
1107 struct buffer_head *bh = journal->j_sb_buffer;
1109 journal->j_sb_buffer = NULL;
1113 * Given a journal_t structure, initialise the various fields for
1114 * startup of a new journaling session. We use this both when creating
1115 * a journal, and after recovering an old journal to reset it for
1119 static int journal_reset(journal_t *journal)
1121 journal_superblock_t *sb = journal->j_superblock;
1122 unsigned long long first, last;
1124 first = be32_to_cpu(sb->s_first);
1125 last = be32_to_cpu(sb->s_maxlen);
1126 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1127 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1129 journal_fail_superblock(journal);
1133 journal->j_first = first;
1134 journal->j_last = last;
1136 journal->j_head = first;
1137 journal->j_tail = first;
1138 journal->j_free = last - first;
1140 journal->j_tail_sequence = journal->j_transaction_sequence;
1141 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1142 journal->j_commit_request = journal->j_commit_sequence;
1144 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1146 /* Add the dynamic fields and write it to disk. */
1147 jbd2_journal_update_superblock(journal, 1);
1148 return jbd2_journal_start_thread(journal);
1152 * void jbd2_journal_update_superblock() - Update journal sb on disk.
1153 * @journal: The journal to update.
1154 * @wait: Set to '0' if you don't want to wait for IO completion.
1156 * Update a journal's dynamic superblock fields and write it to disk,
1157 * optionally waiting for the IO to complete.
1159 void jbd2_journal_update_superblock(journal_t *journal, int wait)
1161 journal_superblock_t *sb = journal->j_superblock;
1162 struct buffer_head *bh = journal->j_sb_buffer;
1165 * As a special case, if the on-disk copy is already marked as needing
1166 * no recovery (s_start == 0) and there are no outstanding transactions
1167 * in the filesystem, then we can safely defer the superblock update
1168 * until the next commit by setting JBD2_FLUSHED. This avoids
1169 * attempting a write to a potential-readonly device.
1171 if (sb->s_start == 0 && journal->j_tail_sequence ==
1172 journal->j_transaction_sequence) {
1173 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1174 "(start %ld, seq %d, errno %d)\n",
1175 journal->j_tail, journal->j_tail_sequence,
1180 if (buffer_write_io_error(bh)) {
1182 * Oh, dear. A previous attempt to write the journal
1183 * superblock failed. This could happen because the
1184 * USB device was yanked out. Or it could happen to
1185 * be a transient write error and maybe the block will
1186 * be remapped. Nothing we can do but to retry the
1187 * write and hope for the best.
1189 printk(KERN_ERR "JBD2: previous I/O error detected "
1190 "for journal superblock update for %s.\n",
1191 journal->j_devname);
1192 clear_buffer_write_io_error(bh);
1193 set_buffer_uptodate(bh);
1196 read_lock(&journal->j_state_lock);
1197 jbd_debug(1, "JBD2: updating superblock (start %ld, seq %d, errno %d)\n",
1198 journal->j_tail, journal->j_tail_sequence, journal->j_errno);
1200 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1201 sb->s_start = cpu_to_be32(journal->j_tail);
1202 sb->s_errno = cpu_to_be32(journal->j_errno);
1203 read_unlock(&journal->j_state_lock);
1205 BUFFER_TRACE(bh, "marking dirty");
1206 mark_buffer_dirty(bh);
1208 sync_dirty_buffer(bh);
1209 if (buffer_write_io_error(bh)) {
1210 printk(KERN_ERR "JBD2: I/O error detected "
1211 "when updating journal superblock for %s.\n",
1212 journal->j_devname);
1213 clear_buffer_write_io_error(bh);
1214 set_buffer_uptodate(bh);
1217 write_dirty_buffer(bh, WRITE);
1220 /* If we have just flushed the log (by marking s_start==0), then
1221 * any future commit will have to be careful to update the
1222 * superblock again to re-record the true start of the log. */
1224 write_lock(&journal->j_state_lock);
1226 journal->j_flags &= ~JBD2_FLUSHED;
1228 journal->j_flags |= JBD2_FLUSHED;
1229 write_unlock(&journal->j_state_lock);
1233 * Read the superblock for a given journal, performing initial
1234 * validation of the format.
1237 static int journal_get_superblock(journal_t *journal)
1239 struct buffer_head *bh;
1240 journal_superblock_t *sb;
1243 bh = journal->j_sb_buffer;
1245 J_ASSERT(bh != NULL);
1246 if (!buffer_uptodate(bh)) {
1247 ll_rw_block(READ, 1, &bh);
1249 if (!buffer_uptodate(bh)) {
1251 "JBD2: IO error reading journal superblock\n");
1256 sb = journal->j_superblock;
1260 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1261 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1262 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1266 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1267 case JBD2_SUPERBLOCK_V1:
1268 journal->j_format_version = 1;
1270 case JBD2_SUPERBLOCK_V2:
1271 journal->j_format_version = 2;
1274 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1278 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1279 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1280 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1281 printk(KERN_WARNING "JBD2: journal file too short\n");
1285 if (be32_to_cpu(sb->s_first) == 0 ||
1286 be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
1288 "JBD2: Invalid start block of journal: %u\n",
1289 be32_to_cpu(sb->s_first));
1296 journal_fail_superblock(journal);
1301 * Load the on-disk journal superblock and read the key fields into the
1305 static int load_superblock(journal_t *journal)
1308 journal_superblock_t *sb;
1310 err = journal_get_superblock(journal);
1314 sb = journal->j_superblock;
1316 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1317 journal->j_tail = be32_to_cpu(sb->s_start);
1318 journal->j_first = be32_to_cpu(sb->s_first);
1319 journal->j_last = be32_to_cpu(sb->s_maxlen);
1320 journal->j_errno = be32_to_cpu(sb->s_errno);
1327 * int jbd2_journal_load() - Read journal from disk.
1328 * @journal: Journal to act on.
1330 * Given a journal_t structure which tells us which disk blocks contain
1331 * a journal, read the journal from disk to initialise the in-memory
1334 int jbd2_journal_load(journal_t *journal)
1337 journal_superblock_t *sb;
1339 err = load_superblock(journal);
1343 sb = journal->j_superblock;
1344 /* If this is a V2 superblock, then we have to check the
1345 * features flags on it. */
1347 if (journal->j_format_version >= 2) {
1348 if ((sb->s_feature_ro_compat &
1349 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1350 (sb->s_feature_incompat &
1351 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1353 "JBD2: Unrecognised features on journal\n");
1359 * Create a slab for this blocksize
1361 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
1365 /* Let the recovery code check whether it needs to recover any
1366 * data from the journal. */
1367 if (jbd2_journal_recover(journal))
1368 goto recovery_error;
1370 if (journal->j_failed_commit) {
1371 printk(KERN_ERR "JBD2: journal transaction %u on %s "
1372 "is corrupt.\n", journal->j_failed_commit,
1373 journal->j_devname);
1377 /* OK, we've finished with the dynamic journal bits:
1378 * reinitialise the dynamic contents of the superblock in memory
1379 * and reset them on disk. */
1380 if (journal_reset(journal))
1381 goto recovery_error;
1383 journal->j_flags &= ~JBD2_ABORT;
1384 journal->j_flags |= JBD2_LOADED;
1388 printk(KERN_WARNING "JBD2: recovery failed\n");
1393 * void jbd2_journal_destroy() - Release a journal_t structure.
1394 * @journal: Journal to act on.
1396 * Release a journal_t structure once it is no longer in use by the
1398 * Return <0 if we couldn't clean up the journal.
1400 int jbd2_journal_destroy(journal_t *journal)
1404 /* Wait for the commit thread to wake up and die. */
1405 journal_kill_thread(journal);
1407 /* Force a final log commit */
1408 if (journal->j_running_transaction)
1409 jbd2_journal_commit_transaction(journal);
1411 /* Force any old transactions to disk */
1413 /* Totally anal locking here... */
1414 spin_lock(&journal->j_list_lock);
1415 while (journal->j_checkpoint_transactions != NULL) {
1416 spin_unlock(&journal->j_list_lock);
1417 mutex_lock(&journal->j_checkpoint_mutex);
1418 jbd2_log_do_checkpoint(journal);
1419 mutex_unlock(&journal->j_checkpoint_mutex);
1420 spin_lock(&journal->j_list_lock);
1423 J_ASSERT(journal->j_running_transaction == NULL);
1424 J_ASSERT(journal->j_committing_transaction == NULL);
1425 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1426 spin_unlock(&journal->j_list_lock);
1428 if (journal->j_sb_buffer) {
1429 if (!is_journal_aborted(journal)) {
1430 /* We can now mark the journal as empty. */
1431 journal->j_tail = 0;
1432 journal->j_tail_sequence =
1433 ++journal->j_transaction_sequence;
1434 jbd2_journal_update_superblock(journal, 1);
1438 brelse(journal->j_sb_buffer);
1441 if (journal->j_proc_entry)
1442 jbd2_stats_proc_exit(journal);
1443 if (journal->j_inode)
1444 iput(journal->j_inode);
1445 if (journal->j_revoke)
1446 jbd2_journal_destroy_revoke(journal);
1447 kfree(journal->j_wbuf);
1455 *int jbd2_journal_check_used_features () - Check if features specified are used.
1456 * @journal: Journal to check.
1457 * @compat: bitmask of compatible features
1458 * @ro: bitmask of features that force read-only mount
1459 * @incompat: bitmask of incompatible features
1461 * Check whether the journal uses all of a given set of
1462 * features. Return true (non-zero) if it does.
1465 int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1466 unsigned long ro, unsigned long incompat)
1468 journal_superblock_t *sb;
1470 if (!compat && !ro && !incompat)
1472 /* Load journal superblock if it is not loaded yet. */
1473 if (journal->j_format_version == 0 &&
1474 journal_get_superblock(journal) != 0)
1476 if (journal->j_format_version == 1)
1479 sb = journal->j_superblock;
1481 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1482 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1483 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1490 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1491 * @journal: Journal to check.
1492 * @compat: bitmask of compatible features
1493 * @ro: bitmask of features that force read-only mount
1494 * @incompat: bitmask of incompatible features
1496 * Check whether the journaling code supports the use of
1497 * all of a given set of features on this journal. Return true
1498 * (non-zero) if it can. */
1500 int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1501 unsigned long ro, unsigned long incompat)
1503 if (!compat && !ro && !incompat)
1506 /* We can support any known requested features iff the
1507 * superblock is in version 2. Otherwise we fail to support any
1508 * extended sb features. */
1510 if (journal->j_format_version != 2)
1513 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1514 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1515 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1522 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1523 * @journal: Journal to act on.
1524 * @compat: bitmask of compatible features
1525 * @ro: bitmask of features that force read-only mount
1526 * @incompat: bitmask of incompatible features
1528 * Mark a given journal feature as present on the
1529 * superblock. Returns true if the requested features could be set.
1533 int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1534 unsigned long ro, unsigned long incompat)
1536 journal_superblock_t *sb;
1538 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1541 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1544 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1545 compat, ro, incompat);
1547 sb = journal->j_superblock;
1549 sb->s_feature_compat |= cpu_to_be32(compat);
1550 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1551 sb->s_feature_incompat |= cpu_to_be32(incompat);
1557 * jbd2_journal_clear_features () - Clear a given journal feature in the
1559 * @journal: Journal to act on.
1560 * @compat: bitmask of compatible features
1561 * @ro: bitmask of features that force read-only mount
1562 * @incompat: bitmask of incompatible features
1564 * Clear a given journal feature as present on the
1567 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1568 unsigned long ro, unsigned long incompat)
1570 journal_superblock_t *sb;
1572 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1573 compat, ro, incompat);
1575 sb = journal->j_superblock;
1577 sb->s_feature_compat &= ~cpu_to_be32(compat);
1578 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1579 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
1581 EXPORT_SYMBOL(jbd2_journal_clear_features);
1584 * int jbd2_journal_update_format () - Update on-disk journal structure.
1585 * @journal: Journal to act on.
1587 * Given an initialised but unloaded journal struct, poke about in the
1588 * on-disk structure to update it to the most recent supported version.
1590 int jbd2_journal_update_format (journal_t *journal)
1592 journal_superblock_t *sb;
1595 err = journal_get_superblock(journal);
1599 sb = journal->j_superblock;
1601 switch (be32_to_cpu(sb->s_header.h_blocktype)) {
1602 case JBD2_SUPERBLOCK_V2:
1604 case JBD2_SUPERBLOCK_V1:
1605 return journal_convert_superblock_v1(journal, sb);
1612 static int journal_convert_superblock_v1(journal_t *journal,
1613 journal_superblock_t *sb)
1615 int offset, blocksize;
1616 struct buffer_head *bh;
1619 "JBD2: Converting superblock from version 1 to 2.\n");
1621 /* Pre-initialise new fields to zero */
1622 offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb);
1623 blocksize = be32_to_cpu(sb->s_blocksize);
1624 memset(&sb->s_feature_compat, 0, blocksize-offset);
1626 sb->s_nr_users = cpu_to_be32(1);
1627 sb->s_header.h_blocktype = cpu_to_be32(JBD2_SUPERBLOCK_V2);
1628 journal->j_format_version = 2;
1630 bh = journal->j_sb_buffer;
1631 BUFFER_TRACE(bh, "marking dirty");
1632 mark_buffer_dirty(bh);
1633 sync_dirty_buffer(bh);
1639 * int jbd2_journal_flush () - Flush journal
1640 * @journal: Journal to act on.
1642 * Flush all data for a given journal to disk and empty the journal.
1643 * Filesystems can use this when remounting readonly to ensure that
1644 * recovery does not need to happen on remount.
1647 int jbd2_journal_flush(journal_t *journal)
1650 transaction_t *transaction = NULL;
1651 unsigned long old_tail;
1653 write_lock(&journal->j_state_lock);
1655 /* Force everything buffered to the log... */
1656 if (journal->j_running_transaction) {
1657 transaction = journal->j_running_transaction;
1658 __jbd2_log_start_commit(journal, transaction->t_tid);
1659 } else if (journal->j_committing_transaction)
1660 transaction = journal->j_committing_transaction;
1662 /* Wait for the log commit to complete... */
1664 tid_t tid = transaction->t_tid;
1666 write_unlock(&journal->j_state_lock);
1667 jbd2_log_wait_commit(journal, tid);
1669 write_unlock(&journal->j_state_lock);
1672 /* ...and flush everything in the log out to disk. */
1673 spin_lock(&journal->j_list_lock);
1674 while (!err && journal->j_checkpoint_transactions != NULL) {
1675 spin_unlock(&journal->j_list_lock);
1676 mutex_lock(&journal->j_checkpoint_mutex);
1677 err = jbd2_log_do_checkpoint(journal);
1678 mutex_unlock(&journal->j_checkpoint_mutex);
1679 spin_lock(&journal->j_list_lock);
1681 spin_unlock(&journal->j_list_lock);
1683 if (is_journal_aborted(journal))
1686 jbd2_cleanup_journal_tail(journal);
1688 /* Finally, mark the journal as really needing no recovery.
1689 * This sets s_start==0 in the underlying superblock, which is
1690 * the magic code for a fully-recovered superblock. Any future
1691 * commits of data to the journal will restore the current
1693 write_lock(&journal->j_state_lock);
1694 old_tail = journal->j_tail;
1695 journal->j_tail = 0;
1696 write_unlock(&journal->j_state_lock);
1697 jbd2_journal_update_superblock(journal, 1);
1698 write_lock(&journal->j_state_lock);
1699 journal->j_tail = old_tail;
1701 J_ASSERT(!journal->j_running_transaction);
1702 J_ASSERT(!journal->j_committing_transaction);
1703 J_ASSERT(!journal->j_checkpoint_transactions);
1704 J_ASSERT(journal->j_head == journal->j_tail);
1705 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1706 write_unlock(&journal->j_state_lock);
1711 * int jbd2_journal_wipe() - Wipe journal contents
1712 * @journal: Journal to act on.
1713 * @write: flag (see below)
1715 * Wipe out all of the contents of a journal, safely. This will produce
1716 * a warning if the journal contains any valid recovery information.
1717 * Must be called between journal_init_*() and jbd2_journal_load().
1719 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1720 * we merely suppress recovery.
1723 int jbd2_journal_wipe(journal_t *journal, int write)
1727 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
1729 err = load_superblock(journal);
1733 if (!journal->j_tail)
1736 printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
1737 write ? "Clearing" : "Ignoring");
1739 err = jbd2_journal_skip_recovery(journal);
1741 jbd2_journal_update_superblock(journal, 1);
1748 * Journal abort has very specific semantics, which we describe
1749 * for journal abort.
1751 * Two internal functions, which provide abort to the jbd layer
1756 * Quick version for internal journal use (doesn't lock the journal).
1757 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1758 * and don't attempt to make any other journal updates.
1760 void __jbd2_journal_abort_hard(journal_t *journal)
1762 transaction_t *transaction;
1764 if (journal->j_flags & JBD2_ABORT)
1767 printk(KERN_ERR "Aborting journal on device %s.\n",
1768 journal->j_devname);
1770 write_lock(&journal->j_state_lock);
1771 journal->j_flags |= JBD2_ABORT;
1772 transaction = journal->j_running_transaction;
1774 __jbd2_log_start_commit(journal, transaction->t_tid);
1775 write_unlock(&journal->j_state_lock);
1778 /* Soft abort: record the abort error status in the journal superblock,
1779 * but don't do any other IO. */
1780 static void __journal_abort_soft (journal_t *journal, int errno)
1782 if (journal->j_flags & JBD2_ABORT)
1785 if (!journal->j_errno)
1786 journal->j_errno = errno;
1788 __jbd2_journal_abort_hard(journal);
1791 jbd2_journal_update_superblock(journal, 1);
1795 * void jbd2_journal_abort () - Shutdown the journal immediately.
1796 * @journal: the journal to shutdown.
1797 * @errno: an error number to record in the journal indicating
1798 * the reason for the shutdown.
1800 * Perform a complete, immediate shutdown of the ENTIRE
1801 * journal (not of a single transaction). This operation cannot be
1802 * undone without closing and reopening the journal.
1804 * The jbd2_journal_abort function is intended to support higher level error
1805 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1808 * Journal abort has very specific semantics. Any existing dirty,
1809 * unjournaled buffers in the main filesystem will still be written to
1810 * disk by bdflush, but the journaling mechanism will be suspended
1811 * immediately and no further transaction commits will be honoured.
1813 * Any dirty, journaled buffers will be written back to disk without
1814 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1815 * filesystem, but we _do_ attempt to leave as much data as possible
1816 * behind for fsck to use for cleanup.
1818 * Any attempt to get a new transaction handle on a journal which is in
1819 * ABORT state will just result in an -EROFS error return. A
1820 * jbd2_journal_stop on an existing handle will return -EIO if we have
1821 * entered abort state during the update.
1823 * Recursive transactions are not disturbed by journal abort until the
1824 * final jbd2_journal_stop, which will receive the -EIO error.
1826 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
1827 * which will be recorded (if possible) in the journal superblock. This
1828 * allows a client to record failure conditions in the middle of a
1829 * transaction without having to complete the transaction to record the
1830 * failure to disk. ext3_error, for example, now uses this
1833 * Errors which originate from within the journaling layer will NOT
1834 * supply an errno; a null errno implies that absolutely no further
1835 * writes are done to the journal (unless there are any already in
1840 void jbd2_journal_abort(journal_t *journal, int errno)
1842 __journal_abort_soft(journal, errno);
1846 * int jbd2_journal_errno () - returns the journal's error state.
1847 * @journal: journal to examine.
1849 * This is the errno number set with jbd2_journal_abort(), the last
1850 * time the journal was mounted - if the journal was stopped
1851 * without calling abort this will be 0.
1853 * If the journal has been aborted on this mount time -EROFS will
1856 int jbd2_journal_errno(journal_t *journal)
1860 read_lock(&journal->j_state_lock);
1861 if (journal->j_flags & JBD2_ABORT)
1864 err = journal->j_errno;
1865 read_unlock(&journal->j_state_lock);
1870 * int jbd2_journal_clear_err () - clears the journal's error state
1871 * @journal: journal to act on.
1873 * An error must be cleared or acked to take a FS out of readonly
1876 int jbd2_journal_clear_err(journal_t *journal)
1880 write_lock(&journal->j_state_lock);
1881 if (journal->j_flags & JBD2_ABORT)
1884 journal->j_errno = 0;
1885 write_unlock(&journal->j_state_lock);
1890 * void jbd2_journal_ack_err() - Ack journal err.
1891 * @journal: journal to act on.
1893 * An error must be cleared or acked to take a FS out of readonly
1896 void jbd2_journal_ack_err(journal_t *journal)
1898 write_lock(&journal->j_state_lock);
1899 if (journal->j_errno)
1900 journal->j_flags |= JBD2_ACK_ERR;
1901 write_unlock(&journal->j_state_lock);
1904 int jbd2_journal_blocks_per_page(struct inode *inode)
1906 return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
1910 * helper functions to deal with 32 or 64bit block numbers.
1912 size_t journal_tag_bytes(journal_t *journal)
1914 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
1915 return JBD2_TAG_SIZE64;
1917 return JBD2_TAG_SIZE32;
1921 * JBD memory management
1923 * These functions are used to allocate block-sized chunks of memory
1924 * used for making copies of buffer_head data. Very often it will be
1925 * page-sized chunks of data, but sometimes it will be in
1926 * sub-page-size chunks. (For example, 16k pages on Power systems
1927 * with a 4k block file system.) For blocks smaller than a page, we
1928 * use a SLAB allocator. There are slab caches for each block size,
1929 * which are allocated at mount time, if necessary, and we only free
1930 * (all of) the slab caches when/if the jbd2 module is unloaded. For
1931 * this reason we don't need to a mutex to protect access to
1932 * jbd2_slab[] allocating or releasing memory; only in
1933 * jbd2_journal_create_slab().
1935 #define JBD2_MAX_SLABS 8
1936 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
1938 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
1939 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
1940 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
1944 static void jbd2_journal_destroy_slabs(void)
1948 for (i = 0; i < JBD2_MAX_SLABS; i++) {
1950 kmem_cache_destroy(jbd2_slab[i]);
1951 jbd2_slab[i] = NULL;
1955 static int jbd2_journal_create_slab(size_t size)
1957 static DEFINE_MUTEX(jbd2_slab_create_mutex);
1958 int i = order_base_2(size) - 10;
1961 if (size == PAGE_SIZE)
1964 if (i >= JBD2_MAX_SLABS)
1967 if (unlikely(i < 0))
1969 mutex_lock(&jbd2_slab_create_mutex);
1971 mutex_unlock(&jbd2_slab_create_mutex);
1972 return 0; /* Already created */
1975 slab_size = 1 << (i+10);
1976 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
1977 slab_size, 0, NULL);
1978 mutex_unlock(&jbd2_slab_create_mutex);
1979 if (!jbd2_slab[i]) {
1980 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
1986 static struct kmem_cache *get_slab(size_t size)
1988 int i = order_base_2(size) - 10;
1990 BUG_ON(i >= JBD2_MAX_SLABS);
1991 if (unlikely(i < 0))
1993 BUG_ON(jbd2_slab[i] == NULL);
1994 return jbd2_slab[i];
1997 void *jbd2_alloc(size_t size, gfp_t flags)
2001 BUG_ON(size & (size-1)); /* Must be a power of 2 */
2003 flags |= __GFP_REPEAT;
2004 if (size == PAGE_SIZE)
2005 ptr = (void *)__get_free_pages(flags, 0);
2006 else if (size > PAGE_SIZE) {
2007 int order = get_order(size);
2010 ptr = (void *)__get_free_pages(flags, order);
2012 ptr = vmalloc(size);
2014 ptr = kmem_cache_alloc(get_slab(size), flags);
2016 /* Check alignment; SLUB has gotten this wrong in the past,
2017 * and this can lead to user data corruption! */
2018 BUG_ON(((unsigned long) ptr) & (size-1));
2023 void jbd2_free(void *ptr, size_t size)
2025 if (size == PAGE_SIZE) {
2026 free_pages((unsigned long)ptr, 0);
2029 if (size > PAGE_SIZE) {
2030 int order = get_order(size);
2033 free_pages((unsigned long)ptr, order);
2038 kmem_cache_free(get_slab(size), ptr);
2042 * Journal_head storage management
2044 static struct kmem_cache *jbd2_journal_head_cache;
2045 #ifdef CONFIG_JBD2_DEBUG
2046 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2049 static int journal_init_jbd2_journal_head_cache(void)
2053 J_ASSERT(jbd2_journal_head_cache == NULL);
2054 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2055 sizeof(struct journal_head),
2057 SLAB_TEMPORARY, /* flags */
2060 if (!jbd2_journal_head_cache) {
2062 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2067 static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
2069 if (jbd2_journal_head_cache) {
2070 kmem_cache_destroy(jbd2_journal_head_cache);
2071 jbd2_journal_head_cache = NULL;
2076 * journal_head splicing and dicing
2078 static struct journal_head *journal_alloc_journal_head(void)
2080 struct journal_head *ret;
2082 #ifdef CONFIG_JBD2_DEBUG
2083 atomic_inc(&nr_journal_heads);
2085 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
2087 jbd_debug(1, "out of memory for journal_head\n");
2088 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2091 ret = kmem_cache_alloc(jbd2_journal_head_cache, GFP_NOFS);
2097 static void journal_free_journal_head(struct journal_head *jh)
2099 #ifdef CONFIG_JBD2_DEBUG
2100 atomic_dec(&nr_journal_heads);
2101 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2103 kmem_cache_free(jbd2_journal_head_cache, jh);
2107 * A journal_head is attached to a buffer_head whenever JBD has an
2108 * interest in the buffer.
2110 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2111 * is set. This bit is tested in core kernel code where we need to take
2112 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2115 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2117 * When a buffer has its BH_JBD bit set it is immune from being released by
2118 * core kernel code, mainly via ->b_count.
2120 * A journal_head is detached from its buffer_head when the journal_head's
2121 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2122 * transaction (b_cp_transaction) hold their references to b_jcount.
2124 * Various places in the kernel want to attach a journal_head to a buffer_head
2125 * _before_ attaching the journal_head to a transaction. To protect the
2126 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2127 * journal_head's b_jcount refcount by one. The caller must call
2128 * jbd2_journal_put_journal_head() to undo this.
2130 * So the typical usage would be:
2132 * (Attach a journal_head if needed. Increments b_jcount)
2133 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2135 * (Get another reference for transaction)
2136 * jbd2_journal_grab_journal_head(bh);
2137 * jh->b_transaction = xxx;
2138 * (Put original reference)
2139 * jbd2_journal_put_journal_head(jh);
2143 * Give a buffer_head a journal_head.
2147 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2149 struct journal_head *jh;
2150 struct journal_head *new_jh = NULL;
2153 if (!buffer_jbd(bh)) {
2154 new_jh = journal_alloc_journal_head();
2155 memset(new_jh, 0, sizeof(*new_jh));
2158 jbd_lock_bh_journal_head(bh);
2159 if (buffer_jbd(bh)) {
2163 (atomic_read(&bh->b_count) > 0) ||
2164 (bh->b_page && bh->b_page->mapping));
2167 jbd_unlock_bh_journal_head(bh);
2172 new_jh = NULL; /* We consumed it */
2177 BUFFER_TRACE(bh, "added journal_head");
2180 jbd_unlock_bh_journal_head(bh);
2182 journal_free_journal_head(new_jh);
2183 return bh->b_private;
2187 * Grab a ref against this buffer_head's journal_head. If it ended up not
2188 * having a journal_head, return NULL
2190 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2192 struct journal_head *jh = NULL;
2194 jbd_lock_bh_journal_head(bh);
2195 if (buffer_jbd(bh)) {
2199 jbd_unlock_bh_journal_head(bh);
2203 static void __journal_remove_journal_head(struct buffer_head *bh)
2205 struct journal_head *jh = bh2jh(bh);
2207 J_ASSERT_JH(jh, jh->b_jcount >= 0);
2208 J_ASSERT_JH(jh, jh->b_transaction == NULL);
2209 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2210 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2211 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2212 J_ASSERT_BH(bh, buffer_jbd(bh));
2213 J_ASSERT_BH(bh, jh2bh(jh) == bh);
2214 BUFFER_TRACE(bh, "remove journal_head");
2215 if (jh->b_frozen_data) {
2216 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2217 jbd2_free(jh->b_frozen_data, bh->b_size);
2219 if (jh->b_committed_data) {
2220 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2221 jbd2_free(jh->b_committed_data, bh->b_size);
2223 bh->b_private = NULL;
2224 jh->b_bh = NULL; /* debug, really */
2225 clear_buffer_jbd(bh);
2226 journal_free_journal_head(jh);
2230 * Drop a reference on the passed journal_head. If it fell to zero then
2231 * release the journal_head from the buffer_head.
2233 void jbd2_journal_put_journal_head(struct journal_head *jh)
2235 struct buffer_head *bh = jh2bh(jh);
2237 jbd_lock_bh_journal_head(bh);
2238 J_ASSERT_JH(jh, jh->b_jcount > 0);
2240 if (!jh->b_jcount) {
2241 __journal_remove_journal_head(bh);
2242 jbd_unlock_bh_journal_head(bh);
2245 jbd_unlock_bh_journal_head(bh);
2249 * Initialize jbd inode head
2251 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2253 jinode->i_transaction = NULL;
2254 jinode->i_next_transaction = NULL;
2255 jinode->i_vfs_inode = inode;
2256 jinode->i_flags = 0;
2257 INIT_LIST_HEAD(&jinode->i_list);
2261 * Function to be called before we start removing inode from memory (i.e.,
2262 * clear_inode() is a fine place to be called from). It removes inode from
2263 * transaction's lists.
2265 void jbd2_journal_release_jbd_inode(journal_t *journal,
2266 struct jbd2_inode *jinode)
2271 spin_lock(&journal->j_list_lock);
2272 /* Is commit writing out inode - we have to wait */
2273 if (test_bit(__JI_COMMIT_RUNNING, &jinode->i_flags)) {
2274 wait_queue_head_t *wq;
2275 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2276 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2277 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2278 spin_unlock(&journal->j_list_lock);
2280 finish_wait(wq, &wait.wait);
2284 if (jinode->i_transaction) {
2285 list_del(&jinode->i_list);
2286 jinode->i_transaction = NULL;
2288 spin_unlock(&journal->j_list_lock);
2294 #ifdef CONFIG_JBD2_DEBUG
2295 u8 jbd2_journal_enable_debug __read_mostly;
2296 EXPORT_SYMBOL(jbd2_journal_enable_debug);
2298 #define JBD2_DEBUG_NAME "jbd2-debug"
2300 static struct dentry *jbd2_debugfs_dir;
2301 static struct dentry *jbd2_debug;
2303 static void __init jbd2_create_debugfs_entry(void)
2305 jbd2_debugfs_dir = debugfs_create_dir("jbd2", NULL);
2306 if (jbd2_debugfs_dir)
2307 jbd2_debug = debugfs_create_u8(JBD2_DEBUG_NAME,
2310 &jbd2_journal_enable_debug);
2313 static void __exit jbd2_remove_debugfs_entry(void)
2315 debugfs_remove(jbd2_debug);
2316 debugfs_remove(jbd2_debugfs_dir);
2321 static void __init jbd2_create_debugfs_entry(void)
2325 static void __exit jbd2_remove_debugfs_entry(void)
2331 #ifdef CONFIG_PROC_FS
2333 #define JBD2_STATS_PROC_NAME "fs/jbd2"
2335 static void __init jbd2_create_jbd_stats_proc_entry(void)
2337 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2340 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2342 if (proc_jbd2_stats)
2343 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2348 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2349 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2353 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
2355 static int __init journal_init_handle_cache(void)
2357 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
2358 if (jbd2_handle_cache == NULL) {
2359 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
2362 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
2363 if (jbd2_inode_cache == NULL) {
2364 printk(KERN_EMERG "JBD2: failed to create inode cache\n");
2365 kmem_cache_destroy(jbd2_handle_cache);
2371 static void jbd2_journal_destroy_handle_cache(void)
2373 if (jbd2_handle_cache)
2374 kmem_cache_destroy(jbd2_handle_cache);
2375 if (jbd2_inode_cache)
2376 kmem_cache_destroy(jbd2_inode_cache);
2381 * Module startup and shutdown
2384 static int __init journal_init_caches(void)
2388 ret = jbd2_journal_init_revoke_caches();
2390 ret = journal_init_jbd2_journal_head_cache();
2392 ret = journal_init_handle_cache();
2396 static void jbd2_journal_destroy_caches(void)
2398 jbd2_journal_destroy_revoke_caches();
2399 jbd2_journal_destroy_jbd2_journal_head_cache();
2400 jbd2_journal_destroy_handle_cache();
2401 jbd2_journal_destroy_slabs();
2404 static int __init journal_init(void)
2408 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2410 ret = journal_init_caches();
2412 jbd2_create_debugfs_entry();
2413 jbd2_create_jbd_stats_proc_entry();
2415 jbd2_journal_destroy_caches();
2420 static void __exit journal_exit(void)
2422 #ifdef CONFIG_JBD2_DEBUG
2423 int n = atomic_read(&nr_journal_heads);
2425 printk(KERN_EMERG "JBD2: leaked %d journal_heads!\n", n);
2427 jbd2_remove_debugfs_entry();
2428 jbd2_remove_jbd_stats_proc_entry();
2429 jbd2_journal_destroy_caches();
2432 MODULE_LICENSE("GPL");
2433 module_init(journal_init);
2434 module_exit(journal_exit);