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>
47 #define CREATE_TRACE_POINTS
48 #include <trace/events/jbd2.h>
50 #include <asm/uaccess.h>
52 #include <asm/system.h>
54 EXPORT_SYMBOL(jbd2_journal_extend
);
55 EXPORT_SYMBOL(jbd2_journal_stop
);
56 EXPORT_SYMBOL(jbd2_journal_lock_updates
);
57 EXPORT_SYMBOL(jbd2_journal_unlock_updates
);
58 EXPORT_SYMBOL(jbd2_journal_get_write_access
);
59 EXPORT_SYMBOL(jbd2_journal_get_create_access
);
60 EXPORT_SYMBOL(jbd2_journal_get_undo_access
);
61 EXPORT_SYMBOL(jbd2_journal_set_triggers
);
62 EXPORT_SYMBOL(jbd2_journal_dirty_metadata
);
63 EXPORT_SYMBOL(jbd2_journal_release_buffer
);
64 EXPORT_SYMBOL(jbd2_journal_forget
);
66 EXPORT_SYMBOL(journal_sync_buffer
);
68 EXPORT_SYMBOL(jbd2_journal_flush
);
69 EXPORT_SYMBOL(jbd2_journal_revoke
);
71 EXPORT_SYMBOL(jbd2_journal_init_dev
);
72 EXPORT_SYMBOL(jbd2_journal_init_inode
);
73 EXPORT_SYMBOL(jbd2_journal_update_format
);
74 EXPORT_SYMBOL(jbd2_journal_check_used_features
);
75 EXPORT_SYMBOL(jbd2_journal_check_available_features
);
76 EXPORT_SYMBOL(jbd2_journal_set_features
);
77 EXPORT_SYMBOL(jbd2_journal_load
);
78 EXPORT_SYMBOL(jbd2_journal_destroy
);
79 EXPORT_SYMBOL(jbd2_journal_abort
);
80 EXPORT_SYMBOL(jbd2_journal_errno
);
81 EXPORT_SYMBOL(jbd2_journal_ack_err
);
82 EXPORT_SYMBOL(jbd2_journal_clear_err
);
83 EXPORT_SYMBOL(jbd2_log_wait_commit
);
84 EXPORT_SYMBOL(jbd2_log_start_commit
);
85 EXPORT_SYMBOL(jbd2_journal_start_commit
);
86 EXPORT_SYMBOL(jbd2_journal_force_commit_nested
);
87 EXPORT_SYMBOL(jbd2_journal_wipe
);
88 EXPORT_SYMBOL(jbd2_journal_blocks_per_page
);
89 EXPORT_SYMBOL(jbd2_journal_invalidatepage
);
90 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers
);
91 EXPORT_SYMBOL(jbd2_journal_force_commit
);
92 EXPORT_SYMBOL(jbd2_journal_file_inode
);
93 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode
);
94 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode
);
95 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate
);
97 static int journal_convert_superblock_v1(journal_t
*, journal_superblock_t
*);
98 static void __journal_abort_soft (journal_t
*journal
, int errno
);
99 static int jbd2_journal_create_slab(size_t slab_size
);
102 * Helper function used to manage commit timeouts
105 static void commit_timeout(unsigned long __data
)
107 struct task_struct
* p
= (struct task_struct
*) __data
;
113 * kjournald2: The main thread function used to manage a logging device
116 * This kernel thread is responsible for two things:
118 * 1) COMMIT: Every so often we need to commit the current state of the
119 * filesystem to disk. The journal thread is responsible for writing
120 * all of the metadata buffers to disk.
122 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
123 * of the data in that part of the log has been rewritten elsewhere on
124 * the disk. Flushing these old buffers to reclaim space in the log is
125 * known as checkpointing, and this thread is responsible for that job.
128 static int kjournald2(void *arg
)
130 journal_t
*journal
= arg
;
131 transaction_t
*transaction
;
134 * Set up an interval timer which can be used to trigger a commit wakeup
135 * after the commit interval expires
137 setup_timer(&journal
->j_commit_timer
, commit_timeout
,
138 (unsigned long)current
);
140 /* Record that the journal thread is running */
141 journal
->j_task
= current
;
142 wake_up(&journal
->j_wait_done_commit
);
145 * And now, wait forever for commit wakeup events.
147 write_lock(&journal
->j_state_lock
);
150 if (journal
->j_flags
& JBD2_UNMOUNT
)
153 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
154 journal
->j_commit_sequence
, journal
->j_commit_request
);
156 if (journal
->j_commit_sequence
!= journal
->j_commit_request
) {
157 jbd_debug(1, "OK, requests differ\n");
158 write_unlock(&journal
->j_state_lock
);
159 del_timer_sync(&journal
->j_commit_timer
);
160 jbd2_journal_commit_transaction(journal
);
161 write_lock(&journal
->j_state_lock
);
165 wake_up(&journal
->j_wait_done_commit
);
166 if (freezing(current
)) {
168 * The simpler the better. Flushing journal isn't a
169 * good idea, because that depends on threads that may
170 * be already stopped.
172 jbd_debug(1, "Now suspending kjournald2\n");
173 write_unlock(&journal
->j_state_lock
);
175 write_lock(&journal
->j_state_lock
);
178 * We assume on resume that commits are already there,
182 int should_sleep
= 1;
184 prepare_to_wait(&journal
->j_wait_commit
, &wait
,
186 if (journal
->j_commit_sequence
!= journal
->j_commit_request
)
188 transaction
= journal
->j_running_transaction
;
189 if (transaction
&& time_after_eq(jiffies
,
190 transaction
->t_expires
))
192 if (journal
->j_flags
& JBD2_UNMOUNT
)
195 write_unlock(&journal
->j_state_lock
);
197 write_lock(&journal
->j_state_lock
);
199 finish_wait(&journal
->j_wait_commit
, &wait
);
202 jbd_debug(1, "kjournald2 wakes\n");
205 * Were we woken up by a commit wakeup event?
207 transaction
= journal
->j_running_transaction
;
208 if (transaction
&& time_after_eq(jiffies
, transaction
->t_expires
)) {
209 journal
->j_commit_request
= transaction
->t_tid
;
210 jbd_debug(1, "woke because of timeout\n");
215 write_unlock(&journal
->j_state_lock
);
216 del_timer_sync(&journal
->j_commit_timer
);
217 journal
->j_task
= NULL
;
218 wake_up(&journal
->j_wait_done_commit
);
219 jbd_debug(1, "Journal thread exiting.\n");
223 static int jbd2_journal_start_thread(journal_t
*journal
)
225 struct task_struct
*t
;
227 t
= kthread_run(kjournald2
, journal
, "jbd2/%s",
232 wait_event(journal
->j_wait_done_commit
, journal
->j_task
!= NULL
);
236 static void journal_kill_thread(journal_t
*journal
)
238 write_lock(&journal
->j_state_lock
);
239 journal
->j_flags
|= JBD2_UNMOUNT
;
241 while (journal
->j_task
) {
242 wake_up(&journal
->j_wait_commit
);
243 write_unlock(&journal
->j_state_lock
);
244 wait_event(journal
->j_wait_done_commit
, journal
->j_task
== NULL
);
245 write_lock(&journal
->j_state_lock
);
247 write_unlock(&journal
->j_state_lock
);
251 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
253 * Writes a metadata buffer to a given disk block. The actual IO is not
254 * performed but a new buffer_head is constructed which labels the data
255 * to be written with the correct destination disk block.
257 * Any magic-number escaping which needs to be done will cause a
258 * copy-out here. If the buffer happens to start with the
259 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
260 * magic number is only written to the log for descripter blocks. In
261 * this case, we copy the data and replace the first word with 0, and we
262 * return a result code which indicates that this buffer needs to be
263 * marked as an escaped buffer in the corresponding log descriptor
264 * block. The missing word can then be restored when the block is read
267 * If the source buffer has already been modified by a new transaction
268 * since we took the last commit snapshot, we use the frozen copy of
269 * that data for IO. If we end up using the existing buffer_head's data
270 * for the write, then we *have* to lock the buffer to prevent anyone
271 * else from using and possibly modifying it while the IO is in
274 * The function returns a pointer to the buffer_heads to be used for IO.
276 * We assume that the journal has already been locked in this function.
283 * Bit 0 set == escape performed on the data
284 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
287 int jbd2_journal_write_metadata_buffer(transaction_t
*transaction
,
288 struct journal_head
*jh_in
,
289 struct journal_head
**jh_out
,
290 unsigned long long blocknr
)
292 int need_copy_out
= 0;
293 int done_copy_out
= 0;
296 struct buffer_head
*new_bh
;
297 struct journal_head
*new_jh
;
298 struct page
*new_page
;
299 unsigned int new_offset
;
300 struct buffer_head
*bh_in
= jh2bh(jh_in
);
301 journal_t
*journal
= transaction
->t_journal
;
304 * The buffer really shouldn't be locked: only the current committing
305 * transaction is allowed to write it, so nobody else is allowed
308 * akpm: except if we're journalling data, and write() output is
309 * also part of a shared mapping, and another thread has
310 * decided to launch a writepage() against this buffer.
312 J_ASSERT_BH(bh_in
, buffer_jbddirty(bh_in
));
315 new_bh
= alloc_buffer_head(GFP_NOFS
);
318 * Failure is not an option, but __GFP_NOFAIL is going
319 * away; so we retry ourselves here.
321 congestion_wait(BLK_RW_ASYNC
, HZ
/50);
325 /* keep subsequent assertions sane */
327 init_buffer(new_bh
, NULL
, NULL
);
328 atomic_set(&new_bh
->b_count
, 1);
329 new_jh
= jbd2_journal_add_journal_head(new_bh
); /* This sleeps */
332 * If a new transaction has already done a buffer copy-out, then
333 * we use that version of the data for the commit.
335 jbd_lock_bh_state(bh_in
);
337 if (jh_in
->b_frozen_data
) {
339 new_page
= virt_to_page(jh_in
->b_frozen_data
);
340 new_offset
= offset_in_page(jh_in
->b_frozen_data
);
342 new_page
= jh2bh(jh_in
)->b_page
;
343 new_offset
= offset_in_page(jh2bh(jh_in
)->b_data
);
346 mapped_data
= kmap_atomic(new_page
, KM_USER0
);
348 * Fire data frozen trigger if data already wasn't frozen. Do this
349 * before checking for escaping, as the trigger may modify the magic
350 * offset. If a copy-out happens afterwards, it will have the correct
351 * data in the buffer.
354 jbd2_buffer_frozen_trigger(jh_in
, mapped_data
+ new_offset
,
360 if (*((__be32
*)(mapped_data
+ new_offset
)) ==
361 cpu_to_be32(JBD2_MAGIC_NUMBER
)) {
365 kunmap_atomic(mapped_data
, KM_USER0
);
368 * Do we need to do a data copy?
370 if (need_copy_out
&& !done_copy_out
) {
373 jbd_unlock_bh_state(bh_in
);
374 tmp
= jbd2_alloc(bh_in
->b_size
, GFP_NOFS
);
376 jbd2_journal_put_journal_head(new_jh
);
379 jbd_lock_bh_state(bh_in
);
380 if (jh_in
->b_frozen_data
) {
381 jbd2_free(tmp
, bh_in
->b_size
);
385 jh_in
->b_frozen_data
= tmp
;
386 mapped_data
= kmap_atomic(new_page
, KM_USER0
);
387 memcpy(tmp
, mapped_data
+ new_offset
, jh2bh(jh_in
)->b_size
);
388 kunmap_atomic(mapped_data
, KM_USER0
);
390 new_page
= virt_to_page(tmp
);
391 new_offset
= offset_in_page(tmp
);
395 * This isn't strictly necessary, as we're using frozen
396 * data for the escaping, but it keeps consistency with
397 * b_frozen_data usage.
399 jh_in
->b_frozen_triggers
= jh_in
->b_triggers
;
403 * Did we need to do an escaping? Now we've done all the
404 * copying, we can finally do so.
407 mapped_data
= kmap_atomic(new_page
, KM_USER0
);
408 *((unsigned int *)(mapped_data
+ new_offset
)) = 0;
409 kunmap_atomic(mapped_data
, KM_USER0
);
412 set_bh_page(new_bh
, new_page
, new_offset
);
413 new_jh
->b_transaction
= NULL
;
414 new_bh
->b_size
= jh2bh(jh_in
)->b_size
;
415 new_bh
->b_bdev
= transaction
->t_journal
->j_dev
;
416 new_bh
->b_blocknr
= blocknr
;
417 set_buffer_mapped(new_bh
);
418 set_buffer_dirty(new_bh
);
423 * The to-be-written buffer needs to get moved to the io queue,
424 * and the original buffer whose contents we are shadowing or
425 * copying is moved to the transaction's shadow queue.
427 JBUFFER_TRACE(jh_in
, "file as BJ_Shadow");
428 spin_lock(&journal
->j_list_lock
);
429 __jbd2_journal_file_buffer(jh_in
, transaction
, BJ_Shadow
);
430 spin_unlock(&journal
->j_list_lock
);
431 jbd_unlock_bh_state(bh_in
);
433 JBUFFER_TRACE(new_jh
, "file as BJ_IO");
434 jbd2_journal_file_buffer(new_jh
, transaction
, BJ_IO
);
436 return do_escape
| (done_copy_out
<< 1);
440 * Allocation code for the journal file. Manage the space left in the
441 * journal, so that we can begin checkpointing when appropriate.
445 * __jbd2_log_space_left: Return the number of free blocks left in the journal.
447 * Called with the journal already locked.
449 * Called under j_state_lock
452 int __jbd2_log_space_left(journal_t
*journal
)
454 int left
= journal
->j_free
;
456 /* assert_spin_locked(&journal->j_state_lock); */
459 * Be pessimistic here about the number of those free blocks which
460 * might be required for log descriptor control blocks.
463 #define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */
465 left
-= MIN_LOG_RESERVED_BLOCKS
;
474 * Called under j_state_lock. Returns true if a transaction commit was started.
476 int __jbd2_log_start_commit(journal_t
*journal
, tid_t target
)
479 * Are we already doing a recent enough commit?
481 if (!tid_geq(journal
->j_commit_request
, target
)) {
483 * We want a new commit: OK, mark the request and wakup the
484 * commit thread. We do _not_ do the commit ourselves.
487 journal
->j_commit_request
= target
;
488 jbd_debug(1, "JBD: requesting commit %d/%d\n",
489 journal
->j_commit_request
,
490 journal
->j_commit_sequence
);
491 wake_up(&journal
->j_wait_commit
);
497 int jbd2_log_start_commit(journal_t
*journal
, tid_t tid
)
501 write_lock(&journal
->j_state_lock
);
502 ret
= __jbd2_log_start_commit(journal
, tid
);
503 write_unlock(&journal
->j_state_lock
);
508 * Force and wait upon a commit if the calling process is not within
509 * transaction. This is used for forcing out undo-protected data which contains
510 * bitmaps, when the fs is running out of space.
512 * We can only force the running transaction if we don't have an active handle;
513 * otherwise, we will deadlock.
515 * Returns true if a transaction was started.
517 int jbd2_journal_force_commit_nested(journal_t
*journal
)
519 transaction_t
*transaction
= NULL
;
522 read_lock(&journal
->j_state_lock
);
523 if (journal
->j_running_transaction
&& !current
->journal_info
) {
524 transaction
= journal
->j_running_transaction
;
525 __jbd2_log_start_commit(journal
, transaction
->t_tid
);
526 } else if (journal
->j_committing_transaction
)
527 transaction
= journal
->j_committing_transaction
;
530 read_unlock(&journal
->j_state_lock
);
531 return 0; /* Nothing to retry */
534 tid
= transaction
->t_tid
;
535 read_unlock(&journal
->j_state_lock
);
536 jbd2_log_wait_commit(journal
, tid
);
541 * Start a commit of the current running transaction (if any). Returns true
542 * if a transaction is going to be committed (or is currently already
543 * committing), and fills its tid in at *ptid
545 int jbd2_journal_start_commit(journal_t
*journal
, tid_t
*ptid
)
549 write_lock(&journal
->j_state_lock
);
550 if (journal
->j_running_transaction
) {
551 tid_t tid
= journal
->j_running_transaction
->t_tid
;
553 __jbd2_log_start_commit(journal
, tid
);
554 /* There's a running transaction and we've just made sure
555 * it's commit has been scheduled. */
559 } else if (journal
->j_committing_transaction
) {
561 * If ext3_write_super() recently started a commit, then we
562 * have to wait for completion of that transaction
565 *ptid
= journal
->j_committing_transaction
->t_tid
;
568 write_unlock(&journal
->j_state_lock
);
573 * Wait for a specified commit to complete.
574 * The caller may not hold the journal lock.
576 int jbd2_log_wait_commit(journal_t
*journal
, tid_t tid
)
580 read_lock(&journal
->j_state_lock
);
581 #ifdef CONFIG_JBD2_DEBUG
582 if (!tid_geq(journal
->j_commit_request
, tid
)) {
584 "%s: error: j_commit_request=%d, tid=%d\n",
585 __func__
, journal
->j_commit_request
, tid
);
588 while (tid_gt(tid
, journal
->j_commit_sequence
)) {
589 jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n",
590 tid
, journal
->j_commit_sequence
);
591 wake_up(&journal
->j_wait_commit
);
592 read_unlock(&journal
->j_state_lock
);
593 wait_event(journal
->j_wait_done_commit
,
594 !tid_gt(tid
, journal
->j_commit_sequence
));
595 read_lock(&journal
->j_state_lock
);
597 read_unlock(&journal
->j_state_lock
);
599 if (unlikely(is_journal_aborted(journal
))) {
600 printk(KERN_EMERG
"journal commit I/O error\n");
607 * Log buffer allocation routines:
610 int jbd2_journal_next_log_block(journal_t
*journal
, unsigned long long *retp
)
612 unsigned long blocknr
;
614 write_lock(&journal
->j_state_lock
);
615 J_ASSERT(journal
->j_free
> 1);
617 blocknr
= journal
->j_head
;
620 if (journal
->j_head
== journal
->j_last
)
621 journal
->j_head
= journal
->j_first
;
622 write_unlock(&journal
->j_state_lock
);
623 return jbd2_journal_bmap(journal
, blocknr
, retp
);
627 * Conversion of logical to physical block numbers for the journal
629 * On external journals the journal blocks are identity-mapped, so
630 * this is a no-op. If needed, we can use j_blk_offset - everything is
633 int jbd2_journal_bmap(journal_t
*journal
, unsigned long blocknr
,
634 unsigned long long *retp
)
637 unsigned long long ret
;
639 if (journal
->j_inode
) {
640 ret
= bmap(journal
->j_inode
, blocknr
);
644 printk(KERN_ALERT
"%s: journal block not found "
645 "at offset %lu on %s\n",
646 __func__
, blocknr
, journal
->j_devname
);
648 __journal_abort_soft(journal
, err
);
651 *retp
= blocknr
; /* +journal->j_blk_offset */
657 * We play buffer_head aliasing tricks to write data/metadata blocks to
658 * the journal without copying their contents, but for journal
659 * descriptor blocks we do need to generate bona fide buffers.
661 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
662 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
663 * But we don't bother doing that, so there will be coherency problems with
664 * mmaps of blockdevs which hold live JBD-controlled filesystems.
666 struct journal_head
*jbd2_journal_get_descriptor_buffer(journal_t
*journal
)
668 struct buffer_head
*bh
;
669 unsigned long long blocknr
;
672 err
= jbd2_journal_next_log_block(journal
, &blocknr
);
677 bh
= __getblk(journal
->j_dev
, blocknr
, journal
->j_blocksize
);
681 memset(bh
->b_data
, 0, journal
->j_blocksize
);
682 set_buffer_uptodate(bh
);
684 BUFFER_TRACE(bh
, "return this buffer");
685 return jbd2_journal_add_journal_head(bh
);
688 struct jbd2_stats_proc_session
{
690 struct transaction_stats_s
*stats
;
695 static void *jbd2_seq_info_start(struct seq_file
*seq
, loff_t
*pos
)
697 return *pos
? NULL
: SEQ_START_TOKEN
;
700 static void *jbd2_seq_info_next(struct seq_file
*seq
, void *v
, loff_t
*pos
)
705 static int jbd2_seq_info_show(struct seq_file
*seq
, void *v
)
707 struct jbd2_stats_proc_session
*s
= seq
->private;
709 if (v
!= SEQ_START_TOKEN
)
711 seq_printf(seq
, "%lu transaction, each up to %u blocks\n",
713 s
->journal
->j_max_transaction_buffers
);
714 if (s
->stats
->ts_tid
== 0)
716 seq_printf(seq
, "average: \n %ums waiting for transaction\n",
717 jiffies_to_msecs(s
->stats
->run
.rs_wait
/ s
->stats
->ts_tid
));
718 seq_printf(seq
, " %ums running transaction\n",
719 jiffies_to_msecs(s
->stats
->run
.rs_running
/ s
->stats
->ts_tid
));
720 seq_printf(seq
, " %ums transaction was being locked\n",
721 jiffies_to_msecs(s
->stats
->run
.rs_locked
/ s
->stats
->ts_tid
));
722 seq_printf(seq
, " %ums flushing data (in ordered mode)\n",
723 jiffies_to_msecs(s
->stats
->run
.rs_flushing
/ s
->stats
->ts_tid
));
724 seq_printf(seq
, " %ums logging transaction\n",
725 jiffies_to_msecs(s
->stats
->run
.rs_logging
/ s
->stats
->ts_tid
));
726 seq_printf(seq
, " %lluus average transaction commit time\n",
727 div_u64(s
->journal
->j_average_commit_time
, 1000));
728 seq_printf(seq
, " %lu handles per transaction\n",
729 s
->stats
->run
.rs_handle_count
/ s
->stats
->ts_tid
);
730 seq_printf(seq
, " %lu blocks per transaction\n",
731 s
->stats
->run
.rs_blocks
/ s
->stats
->ts_tid
);
732 seq_printf(seq
, " %lu logged blocks per transaction\n",
733 s
->stats
->run
.rs_blocks_logged
/ s
->stats
->ts_tid
);
737 static void jbd2_seq_info_stop(struct seq_file
*seq
, void *v
)
741 static const struct seq_operations jbd2_seq_info_ops
= {
742 .start
= jbd2_seq_info_start
,
743 .next
= jbd2_seq_info_next
,
744 .stop
= jbd2_seq_info_stop
,
745 .show
= jbd2_seq_info_show
,
748 static int jbd2_seq_info_open(struct inode
*inode
, struct file
*file
)
750 journal_t
*journal
= PDE(inode
)->data
;
751 struct jbd2_stats_proc_session
*s
;
754 s
= kmalloc(sizeof(*s
), GFP_KERNEL
);
757 size
= sizeof(struct transaction_stats_s
);
758 s
->stats
= kmalloc(size
, GFP_KERNEL
);
759 if (s
->stats
== NULL
) {
763 spin_lock(&journal
->j_history_lock
);
764 memcpy(s
->stats
, &journal
->j_stats
, size
);
765 s
->journal
= journal
;
766 spin_unlock(&journal
->j_history_lock
);
768 rc
= seq_open(file
, &jbd2_seq_info_ops
);
770 struct seq_file
*m
= file
->private_data
;
780 static int jbd2_seq_info_release(struct inode
*inode
, struct file
*file
)
782 struct seq_file
*seq
= file
->private_data
;
783 struct jbd2_stats_proc_session
*s
= seq
->private;
786 return seq_release(inode
, file
);
789 static const struct file_operations jbd2_seq_info_fops
= {
790 .owner
= THIS_MODULE
,
791 .open
= jbd2_seq_info_open
,
794 .release
= jbd2_seq_info_release
,
797 static struct proc_dir_entry
*proc_jbd2_stats
;
799 static void jbd2_stats_proc_init(journal_t
*journal
)
801 journal
->j_proc_entry
= proc_mkdir(journal
->j_devname
, proc_jbd2_stats
);
802 if (journal
->j_proc_entry
) {
803 proc_create_data("info", S_IRUGO
, journal
->j_proc_entry
,
804 &jbd2_seq_info_fops
, journal
);
808 static void jbd2_stats_proc_exit(journal_t
*journal
)
810 remove_proc_entry("info", journal
->j_proc_entry
);
811 remove_proc_entry(journal
->j_devname
, proc_jbd2_stats
);
815 * Management for journal control blocks: functions to create and
816 * destroy journal_t structures, and to initialise and read existing
817 * journal blocks from disk. */
819 /* First: create and setup a journal_t object in memory. We initialise
820 * very few fields yet: that has to wait until we have created the
821 * journal structures from from scratch, or loaded them from disk. */
823 static journal_t
* journal_init_common (void)
828 journal
= kzalloc(sizeof(*journal
), GFP_KERNEL
);
832 init_waitqueue_head(&journal
->j_wait_transaction_locked
);
833 init_waitqueue_head(&journal
->j_wait_logspace
);
834 init_waitqueue_head(&journal
->j_wait_done_commit
);
835 init_waitqueue_head(&journal
->j_wait_checkpoint
);
836 init_waitqueue_head(&journal
->j_wait_commit
);
837 init_waitqueue_head(&journal
->j_wait_updates
);
838 mutex_init(&journal
->j_barrier
);
839 mutex_init(&journal
->j_checkpoint_mutex
);
840 spin_lock_init(&journal
->j_revoke_lock
);
841 spin_lock_init(&journal
->j_list_lock
);
842 rwlock_init(&journal
->j_state_lock
);
844 journal
->j_commit_interval
= (HZ
* JBD2_DEFAULT_MAX_COMMIT_AGE
);
845 journal
->j_min_batch_time
= 0;
846 journal
->j_max_batch_time
= 15000; /* 15ms */
848 /* The journal is marked for error until we succeed with recovery! */
849 journal
->j_flags
= JBD2_ABORT
;
851 /* Set up a default-sized revoke table for the new mount. */
852 err
= jbd2_journal_init_revoke(journal
, JOURNAL_REVOKE_DEFAULT_HASH
);
858 spin_lock_init(&journal
->j_history_lock
);
865 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
867 * Create a journal structure assigned some fixed set of disk blocks to
868 * the journal. We don't actually touch those disk blocks yet, but we
869 * need to set up all of the mapping information to tell the journaling
870 * system where the journal blocks are.
875 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
876 * @bdev: Block device on which to create the journal
877 * @fs_dev: Device which hold journalled filesystem for this journal.
878 * @start: Block nr Start of journal.
879 * @len: Length of the journal in blocks.
880 * @blocksize: blocksize of journalling device
882 * Returns: a newly created journal_t *
884 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
885 * range of blocks on an arbitrary block device.
888 journal_t
* jbd2_journal_init_dev(struct block_device
*bdev
,
889 struct block_device
*fs_dev
,
890 unsigned long long start
, int len
, int blocksize
)
892 journal_t
*journal
= journal_init_common();
893 struct buffer_head
*bh
;
900 /* journal descriptor can store up to n blocks -bzzz */
901 journal
->j_blocksize
= blocksize
;
902 jbd2_stats_proc_init(journal
);
903 n
= journal
->j_blocksize
/ sizeof(journal_block_tag_t
);
904 journal
->j_wbufsize
= n
;
905 journal
->j_wbuf
= kmalloc(n
* sizeof(struct buffer_head
*), GFP_KERNEL
);
906 if (!journal
->j_wbuf
) {
907 printk(KERN_ERR
"%s: Cant allocate bhs for commit thread\n",
911 journal
->j_dev
= bdev
;
912 journal
->j_fs_dev
= fs_dev
;
913 journal
->j_blk_offset
= start
;
914 journal
->j_maxlen
= len
;
915 bdevname(journal
->j_dev
, journal
->j_devname
);
916 p
= journal
->j_devname
;
917 while ((p
= strchr(p
, '/')))
920 bh
= __getblk(journal
->j_dev
, start
, journal
->j_blocksize
);
923 "%s: Cannot get buffer for journal superblock\n",
927 journal
->j_sb_buffer
= bh
;
928 journal
->j_superblock
= (journal_superblock_t
*)bh
->b_data
;
932 kfree(journal
->j_wbuf
);
933 jbd2_stats_proc_exit(journal
);
939 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
940 * @inode: An inode to create the journal in
942 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
943 * the journal. The inode must exist already, must support bmap() and
944 * must have all data blocks preallocated.
946 journal_t
* jbd2_journal_init_inode (struct inode
*inode
)
948 struct buffer_head
*bh
;
949 journal_t
*journal
= journal_init_common();
953 unsigned long long blocknr
;
958 journal
->j_dev
= journal
->j_fs_dev
= inode
->i_sb
->s_bdev
;
959 journal
->j_inode
= inode
;
960 bdevname(journal
->j_dev
, journal
->j_devname
);
961 p
= journal
->j_devname
;
962 while ((p
= strchr(p
, '/')))
964 p
= journal
->j_devname
+ strlen(journal
->j_devname
);
965 sprintf(p
, "-%lu", journal
->j_inode
->i_ino
);
967 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
968 journal
, inode
->i_sb
->s_id
, inode
->i_ino
,
969 (long long) inode
->i_size
,
970 inode
->i_sb
->s_blocksize_bits
, inode
->i_sb
->s_blocksize
);
972 journal
->j_maxlen
= inode
->i_size
>> inode
->i_sb
->s_blocksize_bits
;
973 journal
->j_blocksize
= inode
->i_sb
->s_blocksize
;
974 jbd2_stats_proc_init(journal
);
976 /* journal descriptor can store up to n blocks -bzzz */
977 n
= journal
->j_blocksize
/ sizeof(journal_block_tag_t
);
978 journal
->j_wbufsize
= n
;
979 journal
->j_wbuf
= kmalloc(n
* sizeof(struct buffer_head
*), GFP_KERNEL
);
980 if (!journal
->j_wbuf
) {
981 printk(KERN_ERR
"%s: Cant allocate bhs for commit thread\n",
986 err
= jbd2_journal_bmap(journal
, 0, &blocknr
);
987 /* If that failed, give up */
989 printk(KERN_ERR
"%s: Cannnot locate journal superblock\n",
994 bh
= __getblk(journal
->j_dev
, blocknr
, journal
->j_blocksize
);
997 "%s: Cannot get buffer for journal superblock\n",
1001 journal
->j_sb_buffer
= bh
;
1002 journal
->j_superblock
= (journal_superblock_t
*)bh
->b_data
;
1006 kfree(journal
->j_wbuf
);
1007 jbd2_stats_proc_exit(journal
);
1013 * If the journal init or create aborts, we need to mark the journal
1014 * superblock as being NULL to prevent the journal destroy from writing
1015 * back a bogus superblock.
1017 static void journal_fail_superblock (journal_t
*journal
)
1019 struct buffer_head
*bh
= journal
->j_sb_buffer
;
1021 journal
->j_sb_buffer
= NULL
;
1025 * Given a journal_t structure, initialise the various fields for
1026 * startup of a new journaling session. We use this both when creating
1027 * a journal, and after recovering an old journal to reset it for
1031 static int journal_reset(journal_t
*journal
)
1033 journal_superblock_t
*sb
= journal
->j_superblock
;
1034 unsigned long long first
, last
;
1036 first
= be32_to_cpu(sb
->s_first
);
1037 last
= be32_to_cpu(sb
->s_maxlen
);
1038 if (first
+ JBD2_MIN_JOURNAL_BLOCKS
> last
+ 1) {
1039 printk(KERN_ERR
"JBD: Journal too short (blocks %llu-%llu).\n",
1041 journal_fail_superblock(journal
);
1045 journal
->j_first
= first
;
1046 journal
->j_last
= last
;
1048 journal
->j_head
= first
;
1049 journal
->j_tail
= first
;
1050 journal
->j_free
= last
- first
;
1052 journal
->j_tail_sequence
= journal
->j_transaction_sequence
;
1053 journal
->j_commit_sequence
= journal
->j_transaction_sequence
- 1;
1054 journal
->j_commit_request
= journal
->j_commit_sequence
;
1056 journal
->j_max_transaction_buffers
= journal
->j_maxlen
/ 4;
1058 /* Add the dynamic fields and write it to disk. */
1059 jbd2_journal_update_superblock(journal
, 1);
1060 return jbd2_journal_start_thread(journal
);
1064 * void jbd2_journal_update_superblock() - Update journal sb on disk.
1065 * @journal: The journal to update.
1066 * @wait: Set to '0' if you don't want to wait for IO completion.
1068 * Update a journal's dynamic superblock fields and write it to disk,
1069 * optionally waiting for the IO to complete.
1071 void jbd2_journal_update_superblock(journal_t
*journal
, int wait
)
1073 journal_superblock_t
*sb
= journal
->j_superblock
;
1074 struct buffer_head
*bh
= journal
->j_sb_buffer
;
1077 * As a special case, if the on-disk copy is already marked as needing
1078 * no recovery (s_start == 0) and there are no outstanding transactions
1079 * in the filesystem, then we can safely defer the superblock update
1080 * until the next commit by setting JBD2_FLUSHED. This avoids
1081 * attempting a write to a potential-readonly device.
1083 if (sb
->s_start
== 0 && journal
->j_tail_sequence
==
1084 journal
->j_transaction_sequence
) {
1085 jbd_debug(1,"JBD: Skipping superblock update on recovered sb "
1086 "(start %ld, seq %d, errno %d)\n",
1087 journal
->j_tail
, journal
->j_tail_sequence
,
1092 if (buffer_write_io_error(bh
)) {
1094 * Oh, dear. A previous attempt to write the journal
1095 * superblock failed. This could happen because the
1096 * USB device was yanked out. Or it could happen to
1097 * be a transient write error and maybe the block will
1098 * be remapped. Nothing we can do but to retry the
1099 * write and hope for the best.
1101 printk(KERN_ERR
"JBD2: previous I/O error detected "
1102 "for journal superblock update for %s.\n",
1103 journal
->j_devname
);
1104 clear_buffer_write_io_error(bh
);
1105 set_buffer_uptodate(bh
);
1108 read_lock(&journal
->j_state_lock
);
1109 jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n",
1110 journal
->j_tail
, journal
->j_tail_sequence
, journal
->j_errno
);
1112 sb
->s_sequence
= cpu_to_be32(journal
->j_tail_sequence
);
1113 sb
->s_start
= cpu_to_be32(journal
->j_tail
);
1114 sb
->s_errno
= cpu_to_be32(journal
->j_errno
);
1115 read_unlock(&journal
->j_state_lock
);
1117 BUFFER_TRACE(bh
, "marking dirty");
1118 mark_buffer_dirty(bh
);
1120 sync_dirty_buffer(bh
);
1121 if (buffer_write_io_error(bh
)) {
1122 printk(KERN_ERR
"JBD2: I/O error detected "
1123 "when updating journal superblock for %s.\n",
1124 journal
->j_devname
);
1125 clear_buffer_write_io_error(bh
);
1126 set_buffer_uptodate(bh
);
1129 write_dirty_buffer(bh
, WRITE
);
1132 /* If we have just flushed the log (by marking s_start==0), then
1133 * any future commit will have to be careful to update the
1134 * superblock again to re-record the true start of the log. */
1136 write_lock(&journal
->j_state_lock
);
1138 journal
->j_flags
&= ~JBD2_FLUSHED
;
1140 journal
->j_flags
|= JBD2_FLUSHED
;
1141 write_unlock(&journal
->j_state_lock
);
1145 * Read the superblock for a given journal, performing initial
1146 * validation of the format.
1149 static int journal_get_superblock(journal_t
*journal
)
1151 struct buffer_head
*bh
;
1152 journal_superblock_t
*sb
;
1155 bh
= journal
->j_sb_buffer
;
1157 J_ASSERT(bh
!= NULL
);
1158 if (!buffer_uptodate(bh
)) {
1159 ll_rw_block(READ
, 1, &bh
);
1161 if (!buffer_uptodate(bh
)) {
1163 "JBD: IO error reading journal superblock\n");
1168 sb
= journal
->j_superblock
;
1172 if (sb
->s_header
.h_magic
!= cpu_to_be32(JBD2_MAGIC_NUMBER
) ||
1173 sb
->s_blocksize
!= cpu_to_be32(journal
->j_blocksize
)) {
1174 printk(KERN_WARNING
"JBD: no valid journal superblock found\n");
1178 switch(be32_to_cpu(sb
->s_header
.h_blocktype
)) {
1179 case JBD2_SUPERBLOCK_V1
:
1180 journal
->j_format_version
= 1;
1182 case JBD2_SUPERBLOCK_V2
:
1183 journal
->j_format_version
= 2;
1186 printk(KERN_WARNING
"JBD: unrecognised superblock format ID\n");
1190 if (be32_to_cpu(sb
->s_maxlen
) < journal
->j_maxlen
)
1191 journal
->j_maxlen
= be32_to_cpu(sb
->s_maxlen
);
1192 else if (be32_to_cpu(sb
->s_maxlen
) > journal
->j_maxlen
) {
1193 printk (KERN_WARNING
"JBD: journal file too short\n");
1200 journal_fail_superblock(journal
);
1205 * Load the on-disk journal superblock and read the key fields into the
1209 static int load_superblock(journal_t
*journal
)
1212 journal_superblock_t
*sb
;
1214 err
= journal_get_superblock(journal
);
1218 sb
= journal
->j_superblock
;
1220 journal
->j_tail_sequence
= be32_to_cpu(sb
->s_sequence
);
1221 journal
->j_tail
= be32_to_cpu(sb
->s_start
);
1222 journal
->j_first
= be32_to_cpu(sb
->s_first
);
1223 journal
->j_last
= be32_to_cpu(sb
->s_maxlen
);
1224 journal
->j_errno
= be32_to_cpu(sb
->s_errno
);
1231 * int jbd2_journal_load() - Read journal from disk.
1232 * @journal: Journal to act on.
1234 * Given a journal_t structure which tells us which disk blocks contain
1235 * a journal, read the journal from disk to initialise the in-memory
1238 int jbd2_journal_load(journal_t
*journal
)
1241 journal_superblock_t
*sb
;
1243 err
= load_superblock(journal
);
1247 sb
= journal
->j_superblock
;
1248 /* If this is a V2 superblock, then we have to check the
1249 * features flags on it. */
1251 if (journal
->j_format_version
>= 2) {
1252 if ((sb
->s_feature_ro_compat
&
1253 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES
)) ||
1254 (sb
->s_feature_incompat
&
1255 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES
))) {
1256 printk (KERN_WARNING
1257 "JBD: Unrecognised features on journal\n");
1263 * Create a slab for this blocksize
1265 err
= jbd2_journal_create_slab(be32_to_cpu(sb
->s_blocksize
));
1269 /* Let the recovery code check whether it needs to recover any
1270 * data from the journal. */
1271 if (jbd2_journal_recover(journal
))
1272 goto recovery_error
;
1274 if (journal
->j_failed_commit
) {
1275 printk(KERN_ERR
"JBD2: journal transaction %u on %s "
1276 "is corrupt.\n", journal
->j_failed_commit
,
1277 journal
->j_devname
);
1281 /* OK, we've finished with the dynamic journal bits:
1282 * reinitialise the dynamic contents of the superblock in memory
1283 * and reset them on disk. */
1284 if (journal_reset(journal
))
1285 goto recovery_error
;
1287 journal
->j_flags
&= ~JBD2_ABORT
;
1288 journal
->j_flags
|= JBD2_LOADED
;
1292 printk (KERN_WARNING
"JBD: recovery failed\n");
1297 * void jbd2_journal_destroy() - Release a journal_t structure.
1298 * @journal: Journal to act on.
1300 * Release a journal_t structure once it is no longer in use by the
1302 * Return <0 if we couldn't clean up the journal.
1304 int jbd2_journal_destroy(journal_t
*journal
)
1308 /* Wait for the commit thread to wake up and die. */
1309 journal_kill_thread(journal
);
1311 /* Force a final log commit */
1312 if (journal
->j_running_transaction
)
1313 jbd2_journal_commit_transaction(journal
);
1315 /* Force any old transactions to disk */
1317 /* Totally anal locking here... */
1318 spin_lock(&journal
->j_list_lock
);
1319 while (journal
->j_checkpoint_transactions
!= NULL
) {
1320 spin_unlock(&journal
->j_list_lock
);
1321 mutex_lock(&journal
->j_checkpoint_mutex
);
1322 jbd2_log_do_checkpoint(journal
);
1323 mutex_unlock(&journal
->j_checkpoint_mutex
);
1324 spin_lock(&journal
->j_list_lock
);
1327 J_ASSERT(journal
->j_running_transaction
== NULL
);
1328 J_ASSERT(journal
->j_committing_transaction
== NULL
);
1329 J_ASSERT(journal
->j_checkpoint_transactions
== NULL
);
1330 spin_unlock(&journal
->j_list_lock
);
1332 if (journal
->j_sb_buffer
) {
1333 if (!is_journal_aborted(journal
)) {
1334 /* We can now mark the journal as empty. */
1335 journal
->j_tail
= 0;
1336 journal
->j_tail_sequence
=
1337 ++journal
->j_transaction_sequence
;
1338 jbd2_journal_update_superblock(journal
, 1);
1342 brelse(journal
->j_sb_buffer
);
1345 if (journal
->j_proc_entry
)
1346 jbd2_stats_proc_exit(journal
);
1347 if (journal
->j_inode
)
1348 iput(journal
->j_inode
);
1349 if (journal
->j_revoke
)
1350 jbd2_journal_destroy_revoke(journal
);
1351 kfree(journal
->j_wbuf
);
1359 *int jbd2_journal_check_used_features () - Check if features specified are used.
1360 * @journal: Journal to check.
1361 * @compat: bitmask of compatible features
1362 * @ro: bitmask of features that force read-only mount
1363 * @incompat: bitmask of incompatible features
1365 * Check whether the journal uses all of a given set of
1366 * features. Return true (non-zero) if it does.
1369 int jbd2_journal_check_used_features (journal_t
*journal
, unsigned long compat
,
1370 unsigned long ro
, unsigned long incompat
)
1372 journal_superblock_t
*sb
;
1374 if (!compat
&& !ro
&& !incompat
)
1376 if (journal
->j_format_version
== 1)
1379 sb
= journal
->j_superblock
;
1381 if (((be32_to_cpu(sb
->s_feature_compat
) & compat
) == compat
) &&
1382 ((be32_to_cpu(sb
->s_feature_ro_compat
) & ro
) == ro
) &&
1383 ((be32_to_cpu(sb
->s_feature_incompat
) & incompat
) == incompat
))
1390 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1391 * @journal: Journal to check.
1392 * @compat: bitmask of compatible features
1393 * @ro: bitmask of features that force read-only mount
1394 * @incompat: bitmask of incompatible features
1396 * Check whether the journaling code supports the use of
1397 * all of a given set of features on this journal. Return true
1398 * (non-zero) if it can. */
1400 int jbd2_journal_check_available_features (journal_t
*journal
, unsigned long compat
,
1401 unsigned long ro
, unsigned long incompat
)
1403 if (!compat
&& !ro
&& !incompat
)
1406 /* We can support any known requested features iff the
1407 * superblock is in version 2. Otherwise we fail to support any
1408 * extended sb features. */
1410 if (journal
->j_format_version
!= 2)
1413 if ((compat
& JBD2_KNOWN_COMPAT_FEATURES
) == compat
&&
1414 (ro
& JBD2_KNOWN_ROCOMPAT_FEATURES
) == ro
&&
1415 (incompat
& JBD2_KNOWN_INCOMPAT_FEATURES
) == incompat
)
1422 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1423 * @journal: Journal to act on.
1424 * @compat: bitmask of compatible features
1425 * @ro: bitmask of features that force read-only mount
1426 * @incompat: bitmask of incompatible features
1428 * Mark a given journal feature as present on the
1429 * superblock. Returns true if the requested features could be set.
1433 int jbd2_journal_set_features (journal_t
*journal
, unsigned long compat
,
1434 unsigned long ro
, unsigned long incompat
)
1436 journal_superblock_t
*sb
;
1438 if (jbd2_journal_check_used_features(journal
, compat
, ro
, incompat
))
1441 if (!jbd2_journal_check_available_features(journal
, compat
, ro
, incompat
))
1444 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1445 compat
, ro
, incompat
);
1447 sb
= journal
->j_superblock
;
1449 sb
->s_feature_compat
|= cpu_to_be32(compat
);
1450 sb
->s_feature_ro_compat
|= cpu_to_be32(ro
);
1451 sb
->s_feature_incompat
|= cpu_to_be32(incompat
);
1457 * jbd2_journal_clear_features () - Clear a given journal feature in the
1459 * @journal: Journal to act on.
1460 * @compat: bitmask of compatible features
1461 * @ro: bitmask of features that force read-only mount
1462 * @incompat: bitmask of incompatible features
1464 * Clear a given journal feature as present on the
1467 void jbd2_journal_clear_features(journal_t
*journal
, unsigned long compat
,
1468 unsigned long ro
, unsigned long incompat
)
1470 journal_superblock_t
*sb
;
1472 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1473 compat
, ro
, incompat
);
1475 sb
= journal
->j_superblock
;
1477 sb
->s_feature_compat
&= ~cpu_to_be32(compat
);
1478 sb
->s_feature_ro_compat
&= ~cpu_to_be32(ro
);
1479 sb
->s_feature_incompat
&= ~cpu_to_be32(incompat
);
1481 EXPORT_SYMBOL(jbd2_journal_clear_features
);
1484 * int jbd2_journal_update_format () - Update on-disk journal structure.
1485 * @journal: Journal to act on.
1487 * Given an initialised but unloaded journal struct, poke about in the
1488 * on-disk structure to update it to the most recent supported version.
1490 int jbd2_journal_update_format (journal_t
*journal
)
1492 journal_superblock_t
*sb
;
1495 err
= journal_get_superblock(journal
);
1499 sb
= journal
->j_superblock
;
1501 switch (be32_to_cpu(sb
->s_header
.h_blocktype
)) {
1502 case JBD2_SUPERBLOCK_V2
:
1504 case JBD2_SUPERBLOCK_V1
:
1505 return journal_convert_superblock_v1(journal
, sb
);
1512 static int journal_convert_superblock_v1(journal_t
*journal
,
1513 journal_superblock_t
*sb
)
1515 int offset
, blocksize
;
1516 struct buffer_head
*bh
;
1519 "JBD: Converting superblock from version 1 to 2.\n");
1521 /* Pre-initialise new fields to zero */
1522 offset
= ((char *) &(sb
->s_feature_compat
)) - ((char *) sb
);
1523 blocksize
= be32_to_cpu(sb
->s_blocksize
);
1524 memset(&sb
->s_feature_compat
, 0, blocksize
-offset
);
1526 sb
->s_nr_users
= cpu_to_be32(1);
1527 sb
->s_header
.h_blocktype
= cpu_to_be32(JBD2_SUPERBLOCK_V2
);
1528 journal
->j_format_version
= 2;
1530 bh
= journal
->j_sb_buffer
;
1531 BUFFER_TRACE(bh
, "marking dirty");
1532 mark_buffer_dirty(bh
);
1533 sync_dirty_buffer(bh
);
1539 * int jbd2_journal_flush () - Flush journal
1540 * @journal: Journal to act on.
1542 * Flush all data for a given journal to disk and empty the journal.
1543 * Filesystems can use this when remounting readonly to ensure that
1544 * recovery does not need to happen on remount.
1547 int jbd2_journal_flush(journal_t
*journal
)
1550 transaction_t
*transaction
= NULL
;
1551 unsigned long old_tail
;
1553 write_lock(&journal
->j_state_lock
);
1555 /* Force everything buffered to the log... */
1556 if (journal
->j_running_transaction
) {
1557 transaction
= journal
->j_running_transaction
;
1558 __jbd2_log_start_commit(journal
, transaction
->t_tid
);
1559 } else if (journal
->j_committing_transaction
)
1560 transaction
= journal
->j_committing_transaction
;
1562 /* Wait for the log commit to complete... */
1564 tid_t tid
= transaction
->t_tid
;
1566 write_unlock(&journal
->j_state_lock
);
1567 jbd2_log_wait_commit(journal
, tid
);
1569 write_unlock(&journal
->j_state_lock
);
1572 /* ...and flush everything in the log out to disk. */
1573 spin_lock(&journal
->j_list_lock
);
1574 while (!err
&& journal
->j_checkpoint_transactions
!= NULL
) {
1575 spin_unlock(&journal
->j_list_lock
);
1576 mutex_lock(&journal
->j_checkpoint_mutex
);
1577 err
= jbd2_log_do_checkpoint(journal
);
1578 mutex_unlock(&journal
->j_checkpoint_mutex
);
1579 spin_lock(&journal
->j_list_lock
);
1581 spin_unlock(&journal
->j_list_lock
);
1583 if (is_journal_aborted(journal
))
1586 jbd2_cleanup_journal_tail(journal
);
1588 /* Finally, mark the journal as really needing no recovery.
1589 * This sets s_start==0 in the underlying superblock, which is
1590 * the magic code for a fully-recovered superblock. Any future
1591 * commits of data to the journal will restore the current
1593 write_lock(&journal
->j_state_lock
);
1594 old_tail
= journal
->j_tail
;
1595 journal
->j_tail
= 0;
1596 write_unlock(&journal
->j_state_lock
);
1597 jbd2_journal_update_superblock(journal
, 1);
1598 write_lock(&journal
->j_state_lock
);
1599 journal
->j_tail
= old_tail
;
1601 J_ASSERT(!journal
->j_running_transaction
);
1602 J_ASSERT(!journal
->j_committing_transaction
);
1603 J_ASSERT(!journal
->j_checkpoint_transactions
);
1604 J_ASSERT(journal
->j_head
== journal
->j_tail
);
1605 J_ASSERT(journal
->j_tail_sequence
== journal
->j_transaction_sequence
);
1606 write_unlock(&journal
->j_state_lock
);
1611 * int jbd2_journal_wipe() - Wipe journal contents
1612 * @journal: Journal to act on.
1613 * @write: flag (see below)
1615 * Wipe out all of the contents of a journal, safely. This will produce
1616 * a warning if the journal contains any valid recovery information.
1617 * Must be called between journal_init_*() and jbd2_journal_load().
1619 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
1620 * we merely suppress recovery.
1623 int jbd2_journal_wipe(journal_t
*journal
, int write
)
1627 J_ASSERT (!(journal
->j_flags
& JBD2_LOADED
));
1629 err
= load_superblock(journal
);
1633 if (!journal
->j_tail
)
1636 printk (KERN_WARNING
"JBD: %s recovery information on journal\n",
1637 write
? "Clearing" : "Ignoring");
1639 err
= jbd2_journal_skip_recovery(journal
);
1641 jbd2_journal_update_superblock(journal
, 1);
1648 * Journal abort has very specific semantics, which we describe
1649 * for journal abort.
1651 * Two internal functions, which provide abort to the jbd layer
1656 * Quick version for internal journal use (doesn't lock the journal).
1657 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
1658 * and don't attempt to make any other journal updates.
1660 void __jbd2_journal_abort_hard(journal_t
*journal
)
1662 transaction_t
*transaction
;
1664 if (journal
->j_flags
& JBD2_ABORT
)
1667 printk(KERN_ERR
"Aborting journal on device %s.\n",
1668 journal
->j_devname
);
1670 write_lock(&journal
->j_state_lock
);
1671 journal
->j_flags
|= JBD2_ABORT
;
1672 transaction
= journal
->j_running_transaction
;
1674 __jbd2_log_start_commit(journal
, transaction
->t_tid
);
1675 write_unlock(&journal
->j_state_lock
);
1678 /* Soft abort: record the abort error status in the journal superblock,
1679 * but don't do any other IO. */
1680 static void __journal_abort_soft (journal_t
*journal
, int errno
)
1682 if (journal
->j_flags
& JBD2_ABORT
)
1685 if (!journal
->j_errno
)
1686 journal
->j_errno
= errno
;
1688 __jbd2_journal_abort_hard(journal
);
1691 jbd2_journal_update_superblock(journal
, 1);
1695 * void jbd2_journal_abort () - Shutdown the journal immediately.
1696 * @journal: the journal to shutdown.
1697 * @errno: an error number to record in the journal indicating
1698 * the reason for the shutdown.
1700 * Perform a complete, immediate shutdown of the ENTIRE
1701 * journal (not of a single transaction). This operation cannot be
1702 * undone without closing and reopening the journal.
1704 * The jbd2_journal_abort function is intended to support higher level error
1705 * recovery mechanisms such as the ext2/ext3 remount-readonly error
1708 * Journal abort has very specific semantics. Any existing dirty,
1709 * unjournaled buffers in the main filesystem will still be written to
1710 * disk by bdflush, but the journaling mechanism will be suspended
1711 * immediately and no further transaction commits will be honoured.
1713 * Any dirty, journaled buffers will be written back to disk without
1714 * hitting the journal. Atomicity cannot be guaranteed on an aborted
1715 * filesystem, but we _do_ attempt to leave as much data as possible
1716 * behind for fsck to use for cleanup.
1718 * Any attempt to get a new transaction handle on a journal which is in
1719 * ABORT state will just result in an -EROFS error return. A
1720 * jbd2_journal_stop on an existing handle will return -EIO if we have
1721 * entered abort state during the update.
1723 * Recursive transactions are not disturbed by journal abort until the
1724 * final jbd2_journal_stop, which will receive the -EIO error.
1726 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
1727 * which will be recorded (if possible) in the journal superblock. This
1728 * allows a client to record failure conditions in the middle of a
1729 * transaction without having to complete the transaction to record the
1730 * failure to disk. ext3_error, for example, now uses this
1733 * Errors which originate from within the journaling layer will NOT
1734 * supply an errno; a null errno implies that absolutely no further
1735 * writes are done to the journal (unless there are any already in
1740 void jbd2_journal_abort(journal_t
*journal
, int errno
)
1742 __journal_abort_soft(journal
, errno
);
1746 * int jbd2_journal_errno () - returns the journal's error state.
1747 * @journal: journal to examine.
1749 * This is the errno number set with jbd2_journal_abort(), the last
1750 * time the journal was mounted - if the journal was stopped
1751 * without calling abort this will be 0.
1753 * If the journal has been aborted on this mount time -EROFS will
1756 int jbd2_journal_errno(journal_t
*journal
)
1760 read_lock(&journal
->j_state_lock
);
1761 if (journal
->j_flags
& JBD2_ABORT
)
1764 err
= journal
->j_errno
;
1765 read_unlock(&journal
->j_state_lock
);
1770 * int jbd2_journal_clear_err () - clears the journal's error state
1771 * @journal: journal to act on.
1773 * An error must be cleared or acked to take a FS out of readonly
1776 int jbd2_journal_clear_err(journal_t
*journal
)
1780 write_lock(&journal
->j_state_lock
);
1781 if (journal
->j_flags
& JBD2_ABORT
)
1784 journal
->j_errno
= 0;
1785 write_unlock(&journal
->j_state_lock
);
1790 * void jbd2_journal_ack_err() - Ack journal err.
1791 * @journal: journal to act on.
1793 * An error must be cleared or acked to take a FS out of readonly
1796 void jbd2_journal_ack_err(journal_t
*journal
)
1798 write_lock(&journal
->j_state_lock
);
1799 if (journal
->j_errno
)
1800 journal
->j_flags
|= JBD2_ACK_ERR
;
1801 write_unlock(&journal
->j_state_lock
);
1804 int jbd2_journal_blocks_per_page(struct inode
*inode
)
1806 return 1 << (PAGE_CACHE_SHIFT
- inode
->i_sb
->s_blocksize_bits
);
1810 * helper functions to deal with 32 or 64bit block numbers.
1812 size_t journal_tag_bytes(journal_t
*journal
)
1814 if (JBD2_HAS_INCOMPAT_FEATURE(journal
, JBD2_FEATURE_INCOMPAT_64BIT
))
1815 return JBD2_TAG_SIZE64
;
1817 return JBD2_TAG_SIZE32
;
1821 * JBD memory management
1823 * These functions are used to allocate block-sized chunks of memory
1824 * used for making copies of buffer_head data. Very often it will be
1825 * page-sized chunks of data, but sometimes it will be in
1826 * sub-page-size chunks. (For example, 16k pages on Power systems
1827 * with a 4k block file system.) For blocks smaller than a page, we
1828 * use a SLAB allocator. There are slab caches for each block size,
1829 * which are allocated at mount time, if necessary, and we only free
1830 * (all of) the slab caches when/if the jbd2 module is unloaded. For
1831 * this reason we don't need to a mutex to protect access to
1832 * jbd2_slab[] allocating or releasing memory; only in
1833 * jbd2_journal_create_slab().
1835 #define JBD2_MAX_SLABS 8
1836 static struct kmem_cache
*jbd2_slab
[JBD2_MAX_SLABS
];
1837 static DECLARE_MUTEX(jbd2_slab_create_sem
);
1839 static const char *jbd2_slab_names
[JBD2_MAX_SLABS
] = {
1840 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
1841 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
1845 static void jbd2_journal_destroy_slabs(void)
1849 for (i
= 0; i
< JBD2_MAX_SLABS
; i
++) {
1851 kmem_cache_destroy(jbd2_slab
[i
]);
1852 jbd2_slab
[i
] = NULL
;
1856 static int jbd2_journal_create_slab(size_t size
)
1858 int i
= order_base_2(size
) - 10;
1861 if (size
== PAGE_SIZE
)
1864 if (i
>= JBD2_MAX_SLABS
)
1867 if (unlikely(i
< 0))
1869 down(&jbd2_slab_create_sem
);
1871 up(&jbd2_slab_create_sem
);
1872 return 0; /* Already created */
1875 slab_size
= 1 << (i
+10);
1876 jbd2_slab
[i
] = kmem_cache_create(jbd2_slab_names
[i
], slab_size
,
1877 slab_size
, 0, NULL
);
1878 up(&jbd2_slab_create_sem
);
1879 if (!jbd2_slab
[i
]) {
1880 printk(KERN_EMERG
"JBD2: no memory for jbd2_slab cache\n");
1886 static struct kmem_cache
*get_slab(size_t size
)
1888 int i
= order_base_2(size
) - 10;
1890 BUG_ON(i
>= JBD2_MAX_SLABS
);
1891 if (unlikely(i
< 0))
1893 BUG_ON(jbd2_slab
[i
] == NULL
);
1894 return jbd2_slab
[i
];
1897 void *jbd2_alloc(size_t size
, gfp_t flags
)
1901 BUG_ON(size
& (size
-1)); /* Must be a power of 2 */
1903 flags
|= __GFP_REPEAT
;
1904 if (size
== PAGE_SIZE
)
1905 ptr
= (void *)__get_free_pages(flags
, 0);
1906 else if (size
> PAGE_SIZE
) {
1907 int order
= get_order(size
);
1910 ptr
= (void *)__get_free_pages(flags
, order
);
1912 ptr
= vmalloc(size
);
1914 ptr
= kmem_cache_alloc(get_slab(size
), flags
);
1916 /* Check alignment; SLUB has gotten this wrong in the past,
1917 * and this can lead to user data corruption! */
1918 BUG_ON(((unsigned long) ptr
) & (size
-1));
1923 void jbd2_free(void *ptr
, size_t size
)
1925 if (size
== PAGE_SIZE
) {
1926 free_pages((unsigned long)ptr
, 0);
1929 if (size
> PAGE_SIZE
) {
1930 int order
= get_order(size
);
1933 free_pages((unsigned long)ptr
, order
);
1938 kmem_cache_free(get_slab(size
), ptr
);
1942 * Journal_head storage management
1944 static struct kmem_cache
*jbd2_journal_head_cache
;
1945 #ifdef CONFIG_JBD2_DEBUG
1946 static atomic_t nr_journal_heads
= ATOMIC_INIT(0);
1949 static int journal_init_jbd2_journal_head_cache(void)
1953 J_ASSERT(jbd2_journal_head_cache
== NULL
);
1954 jbd2_journal_head_cache
= kmem_cache_create("jbd2_journal_head",
1955 sizeof(struct journal_head
),
1957 SLAB_TEMPORARY
, /* flags */
1960 if (!jbd2_journal_head_cache
) {
1962 printk(KERN_EMERG
"JBD: no memory for journal_head cache\n");
1967 static void jbd2_journal_destroy_jbd2_journal_head_cache(void)
1969 if (jbd2_journal_head_cache
) {
1970 kmem_cache_destroy(jbd2_journal_head_cache
);
1971 jbd2_journal_head_cache
= NULL
;
1976 * journal_head splicing and dicing
1978 static struct journal_head
*journal_alloc_journal_head(void)
1980 struct journal_head
*ret
;
1981 static unsigned long last_warning
;
1983 #ifdef CONFIG_JBD2_DEBUG
1984 atomic_inc(&nr_journal_heads
);
1986 ret
= kmem_cache_alloc(jbd2_journal_head_cache
, GFP_NOFS
);
1988 jbd_debug(1, "out of memory for journal_head\n");
1989 if (time_after(jiffies
, last_warning
+ 5*HZ
)) {
1990 printk(KERN_NOTICE
"ENOMEM in %s, retrying.\n",
1992 last_warning
= jiffies
;
1996 ret
= kmem_cache_alloc(jbd2_journal_head_cache
, GFP_NOFS
);
2002 static void journal_free_journal_head(struct journal_head
*jh
)
2004 #ifdef CONFIG_JBD2_DEBUG
2005 atomic_dec(&nr_journal_heads
);
2006 memset(jh
, JBD2_POISON_FREE
, sizeof(*jh
));
2008 kmem_cache_free(jbd2_journal_head_cache
, jh
);
2012 * A journal_head is attached to a buffer_head whenever JBD has an
2013 * interest in the buffer.
2015 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2016 * is set. This bit is tested in core kernel code where we need to take
2017 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2020 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2022 * When a buffer has its BH_JBD bit set it is immune from being released by
2023 * core kernel code, mainly via ->b_count.
2025 * A journal_head may be detached from its buffer_head when the journal_head's
2026 * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL.
2027 * Various places in JBD call jbd2_journal_remove_journal_head() to indicate that the
2028 * journal_head can be dropped if needed.
2030 * Various places in the kernel want to attach a journal_head to a buffer_head
2031 * _before_ attaching the journal_head to a transaction. To protect the
2032 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2033 * journal_head's b_jcount refcount by one. The caller must call
2034 * jbd2_journal_put_journal_head() to undo this.
2036 * So the typical usage would be:
2038 * (Attach a journal_head if needed. Increments b_jcount)
2039 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2041 * jh->b_transaction = xxx;
2042 * jbd2_journal_put_journal_head(jh);
2044 * Now, the journal_head's b_jcount is zero, but it is safe from being released
2045 * because it has a non-zero b_transaction.
2049 * Give a buffer_head a journal_head.
2051 * Doesn't need the journal lock.
2054 struct journal_head
*jbd2_journal_add_journal_head(struct buffer_head
*bh
)
2056 struct journal_head
*jh
;
2057 struct journal_head
*new_jh
= NULL
;
2060 if (!buffer_jbd(bh
)) {
2061 new_jh
= journal_alloc_journal_head();
2062 memset(new_jh
, 0, sizeof(*new_jh
));
2065 jbd_lock_bh_journal_head(bh
);
2066 if (buffer_jbd(bh
)) {
2070 (atomic_read(&bh
->b_count
) > 0) ||
2071 (bh
->b_page
&& bh
->b_page
->mapping
));
2074 jbd_unlock_bh_journal_head(bh
);
2079 new_jh
= NULL
; /* We consumed it */
2084 BUFFER_TRACE(bh
, "added journal_head");
2087 jbd_unlock_bh_journal_head(bh
);
2089 journal_free_journal_head(new_jh
);
2090 return bh
->b_private
;
2094 * Grab a ref against this buffer_head's journal_head. If it ended up not
2095 * having a journal_head, return NULL
2097 struct journal_head
*jbd2_journal_grab_journal_head(struct buffer_head
*bh
)
2099 struct journal_head
*jh
= NULL
;
2101 jbd_lock_bh_journal_head(bh
);
2102 if (buffer_jbd(bh
)) {
2106 jbd_unlock_bh_journal_head(bh
);
2110 static void __journal_remove_journal_head(struct buffer_head
*bh
)
2112 struct journal_head
*jh
= bh2jh(bh
);
2114 J_ASSERT_JH(jh
, jh
->b_jcount
>= 0);
2117 if (jh
->b_jcount
== 0) {
2118 if (jh
->b_transaction
== NULL
&&
2119 jh
->b_next_transaction
== NULL
&&
2120 jh
->b_cp_transaction
== NULL
) {
2121 J_ASSERT_JH(jh
, jh
->b_jlist
== BJ_None
);
2122 J_ASSERT_BH(bh
, buffer_jbd(bh
));
2123 J_ASSERT_BH(bh
, jh2bh(jh
) == bh
);
2124 BUFFER_TRACE(bh
, "remove journal_head");
2125 if (jh
->b_frozen_data
) {
2126 printk(KERN_WARNING
"%s: freeing "
2129 jbd2_free(jh
->b_frozen_data
, bh
->b_size
);
2131 if (jh
->b_committed_data
) {
2132 printk(KERN_WARNING
"%s: freeing "
2133 "b_committed_data\n",
2135 jbd2_free(jh
->b_committed_data
, bh
->b_size
);
2137 bh
->b_private
= NULL
;
2138 jh
->b_bh
= NULL
; /* debug, really */
2139 clear_buffer_jbd(bh
);
2141 journal_free_journal_head(jh
);
2143 BUFFER_TRACE(bh
, "journal_head was locked");
2149 * jbd2_journal_remove_journal_head(): if the buffer isn't attached to a transaction
2150 * and has a zero b_jcount then remove and release its journal_head. If we did
2151 * see that the buffer is not used by any transaction we also "logically"
2152 * decrement ->b_count.
2154 * We in fact take an additional increment on ->b_count as a convenience,
2155 * because the caller usually wants to do additional things with the bh
2156 * after calling here.
2157 * The caller of jbd2_journal_remove_journal_head() *must* run __brelse(bh) at some
2158 * time. Once the caller has run __brelse(), the buffer is eligible for
2159 * reaping by try_to_free_buffers().
2161 void jbd2_journal_remove_journal_head(struct buffer_head
*bh
)
2163 jbd_lock_bh_journal_head(bh
);
2164 __journal_remove_journal_head(bh
);
2165 jbd_unlock_bh_journal_head(bh
);
2169 * Drop a reference on the passed journal_head. If it fell to zero then try to
2170 * release the journal_head from the buffer_head.
2172 void jbd2_journal_put_journal_head(struct journal_head
*jh
)
2174 struct buffer_head
*bh
= jh2bh(jh
);
2176 jbd_lock_bh_journal_head(bh
);
2177 J_ASSERT_JH(jh
, jh
->b_jcount
> 0);
2179 if (!jh
->b_jcount
&& !jh
->b_transaction
) {
2180 __journal_remove_journal_head(bh
);
2183 jbd_unlock_bh_journal_head(bh
);
2187 * Initialize jbd inode head
2189 void jbd2_journal_init_jbd_inode(struct jbd2_inode
*jinode
, struct inode
*inode
)
2191 jinode
->i_transaction
= NULL
;
2192 jinode
->i_next_transaction
= NULL
;
2193 jinode
->i_vfs_inode
= inode
;
2194 jinode
->i_flags
= 0;
2195 INIT_LIST_HEAD(&jinode
->i_list
);
2199 * Function to be called before we start removing inode from memory (i.e.,
2200 * clear_inode() is a fine place to be called from). It removes inode from
2201 * transaction's lists.
2203 void jbd2_journal_release_jbd_inode(journal_t
*journal
,
2204 struct jbd2_inode
*jinode
)
2209 spin_lock(&journal
->j_list_lock
);
2210 /* Is commit writing out inode - we have to wait */
2211 if (test_bit(__JI_COMMIT_RUNNING
, &jinode
->i_flags
)) {
2212 wait_queue_head_t
*wq
;
2213 DEFINE_WAIT_BIT(wait
, &jinode
->i_flags
, __JI_COMMIT_RUNNING
);
2214 wq
= bit_waitqueue(&jinode
->i_flags
, __JI_COMMIT_RUNNING
);
2215 prepare_to_wait(wq
, &wait
.wait
, TASK_UNINTERRUPTIBLE
);
2216 spin_unlock(&journal
->j_list_lock
);
2218 finish_wait(wq
, &wait
.wait
);
2222 if (jinode
->i_transaction
) {
2223 list_del(&jinode
->i_list
);
2224 jinode
->i_transaction
= NULL
;
2226 spin_unlock(&journal
->j_list_lock
);
2232 #ifdef CONFIG_JBD2_DEBUG
2233 u8 jbd2_journal_enable_debug __read_mostly
;
2234 EXPORT_SYMBOL(jbd2_journal_enable_debug
);
2236 #define JBD2_DEBUG_NAME "jbd2-debug"
2238 static struct dentry
*jbd2_debugfs_dir
;
2239 static struct dentry
*jbd2_debug
;
2241 static void __init
jbd2_create_debugfs_entry(void)
2243 jbd2_debugfs_dir
= debugfs_create_dir("jbd2", NULL
);
2244 if (jbd2_debugfs_dir
)
2245 jbd2_debug
= debugfs_create_u8(JBD2_DEBUG_NAME
,
2248 &jbd2_journal_enable_debug
);
2251 static void __exit
jbd2_remove_debugfs_entry(void)
2253 debugfs_remove(jbd2_debug
);
2254 debugfs_remove(jbd2_debugfs_dir
);
2259 static void __init
jbd2_create_debugfs_entry(void)
2263 static void __exit
jbd2_remove_debugfs_entry(void)
2269 #ifdef CONFIG_PROC_FS
2271 #define JBD2_STATS_PROC_NAME "fs/jbd2"
2273 static void __init
jbd2_create_jbd_stats_proc_entry(void)
2275 proc_jbd2_stats
= proc_mkdir(JBD2_STATS_PROC_NAME
, NULL
);
2278 static void __exit
jbd2_remove_jbd_stats_proc_entry(void)
2280 if (proc_jbd2_stats
)
2281 remove_proc_entry(JBD2_STATS_PROC_NAME
, NULL
);
2286 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2287 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2291 struct kmem_cache
*jbd2_handle_cache
;
2293 static int __init
journal_init_handle_cache(void)
2295 jbd2_handle_cache
= kmem_cache_create("jbd2_journal_handle",
2298 SLAB_TEMPORARY
, /* flags */
2300 if (jbd2_handle_cache
== NULL
) {
2301 printk(KERN_EMERG
"JBD: failed to create handle cache\n");
2307 static void jbd2_journal_destroy_handle_cache(void)
2309 if (jbd2_handle_cache
)
2310 kmem_cache_destroy(jbd2_handle_cache
);
2314 * Module startup and shutdown
2317 static int __init
journal_init_caches(void)
2321 ret
= jbd2_journal_init_revoke_caches();
2323 ret
= journal_init_jbd2_journal_head_cache();
2325 ret
= journal_init_handle_cache();
2329 static void jbd2_journal_destroy_caches(void)
2331 jbd2_journal_destroy_revoke_caches();
2332 jbd2_journal_destroy_jbd2_journal_head_cache();
2333 jbd2_journal_destroy_handle_cache();
2334 jbd2_journal_destroy_slabs();
2337 static int __init
journal_init(void)
2341 BUILD_BUG_ON(sizeof(struct journal_superblock_s
) != 1024);
2343 ret
= journal_init_caches();
2345 jbd2_create_debugfs_entry();
2346 jbd2_create_jbd_stats_proc_entry();
2348 jbd2_journal_destroy_caches();
2353 static void __exit
journal_exit(void)
2355 #ifdef CONFIG_JBD2_DEBUG
2356 int n
= atomic_read(&nr_journal_heads
);
2358 printk(KERN_EMERG
"JBD: leaked %d journal_heads!\n", n
);
2360 jbd2_remove_debugfs_entry();
2361 jbd2_remove_jbd_stats_proc_entry();
2362 jbd2_journal_destroy_caches();
2366 * jbd2_dev_to_name is a utility function used by the jbd2 and ext4
2367 * tracing infrastructure to map a dev_t to a device name.
2369 * The caller should use rcu_read_lock() in order to make sure the
2370 * device name stays valid until its done with it. We use
2371 * rcu_read_lock() as well to make sure we're safe in case the caller
2372 * gets sloppy, and because rcu_read_lock() is cheap and can be safely
2375 struct devname_cache
{
2376 struct rcu_head rcu
;
2378 char devname
[BDEVNAME_SIZE
];
2380 #define CACHE_SIZE_BITS 6
2381 static struct devname_cache
*devcache
[1 << CACHE_SIZE_BITS
];
2382 static DEFINE_SPINLOCK(devname_cache_lock
);
2384 static void free_devcache(struct rcu_head
*rcu
)
2389 const char *jbd2_dev_to_name(dev_t device
)
2391 int i
= hash_32(device
, CACHE_SIZE_BITS
);
2393 struct block_device
*bd
;
2394 static struct devname_cache
*new_dev
;
2397 if (devcache
[i
] && devcache
[i
]->device
== device
) {
2398 ret
= devcache
[i
]->devname
;
2404 new_dev
= kmalloc(sizeof(struct devname_cache
), GFP_KERNEL
);
2406 return "NODEV-ALLOCFAILURE"; /* Something non-NULL */
2407 spin_lock(&devname_cache_lock
);
2409 if (devcache
[i
]->device
== device
) {
2411 ret
= devcache
[i
]->devname
;
2412 spin_unlock(&devname_cache_lock
);
2415 call_rcu(&devcache
[i
]->rcu
, free_devcache
);
2417 devcache
[i
] = new_dev
;
2418 devcache
[i
]->device
= device
;
2421 bdevname(bd
, devcache
[i
]->devname
);
2424 __bdevname(device
, devcache
[i
]->devname
);
2425 ret
= devcache
[i
]->devname
;
2426 spin_unlock(&devname_cache_lock
);
2429 EXPORT_SYMBOL(jbd2_dev_to_name
);
2431 MODULE_LICENSE("GPL");
2432 module_init(journal_init
);
2433 module_exit(journal_exit
);