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1/*
2 * linux/fs/jbd2/journal.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
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.
11 *
12 * Generic filesystem journal-writing code; part of the ext2fs
13 * journaling system.
14 *
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.
18 *
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).
23 */
24
25#include <linux/module.h>
26#include <linux/time.h>
27#include <linux/fs.h>
28#include <linux/jbd2.h>
29#include <linux/errno.h>
30#include <linux/slab.h>
31#include <linux/init.h>
32#include <linux/mm.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/seq_file.h>
39#include <linux/math64.h>
40#include <linux/hash.h>
41#include <linux/log2.h>
42#include <linux/vmalloc.h>
43#include <linux/backing-dev.h>
44#include <linux/bitops.h>
45#include <linux/ratelimit.h>
46
47#define CREATE_TRACE_POINTS
48#include <trace/events/jbd2.h>
49
50#include <asm/uaccess.h>
51#include <asm/page.h>
52
53#ifdef CONFIG_JBD2_DEBUG
54ushort jbd2_journal_enable_debug __read_mostly;
55EXPORT_SYMBOL(jbd2_journal_enable_debug);
56
57module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
58MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
59#endif
60
61EXPORT_SYMBOL(jbd2_journal_extend);
62EXPORT_SYMBOL(jbd2_journal_stop);
63EXPORT_SYMBOL(jbd2_journal_lock_updates);
64EXPORT_SYMBOL(jbd2_journal_unlock_updates);
65EXPORT_SYMBOL(jbd2_journal_get_write_access);
66EXPORT_SYMBOL(jbd2_journal_get_create_access);
67EXPORT_SYMBOL(jbd2_journal_get_undo_access);
68EXPORT_SYMBOL(jbd2_journal_set_triggers);
69EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
70EXPORT_SYMBOL(jbd2_journal_forget);
71#if 0
72EXPORT_SYMBOL(journal_sync_buffer);
73#endif
74EXPORT_SYMBOL(jbd2_journal_flush);
75EXPORT_SYMBOL(jbd2_journal_revoke);
76
77EXPORT_SYMBOL(jbd2_journal_init_dev);
78EXPORT_SYMBOL(jbd2_journal_init_inode);
79EXPORT_SYMBOL(jbd2_journal_check_used_features);
80EXPORT_SYMBOL(jbd2_journal_check_available_features);
81EXPORT_SYMBOL(jbd2_journal_set_features);
82EXPORT_SYMBOL(jbd2_journal_load);
83EXPORT_SYMBOL(jbd2_journal_destroy);
84EXPORT_SYMBOL(jbd2_journal_abort);
85EXPORT_SYMBOL(jbd2_journal_errno);
86EXPORT_SYMBOL(jbd2_journal_ack_err);
87EXPORT_SYMBOL(jbd2_journal_clear_err);
88EXPORT_SYMBOL(jbd2_log_wait_commit);
89EXPORT_SYMBOL(jbd2_log_start_commit);
90EXPORT_SYMBOL(jbd2_journal_start_commit);
91EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
92EXPORT_SYMBOL(jbd2_journal_wipe);
93EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
94EXPORT_SYMBOL(jbd2_journal_invalidatepage);
95EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
96EXPORT_SYMBOL(jbd2_journal_force_commit);
97EXPORT_SYMBOL(jbd2_journal_file_inode);
98EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
99EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
100EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
101EXPORT_SYMBOL(jbd2_inode_cache);
102
103static void __journal_abort_soft (journal_t *journal, int errno);
104static int jbd2_journal_create_slab(size_t slab_size);
105
106#ifdef CONFIG_JBD2_DEBUG
107void __jbd2_debug(int level, const char *file, const char *func,
108 unsigned int line, const char *fmt, ...)
109{
110 struct va_format vaf;
111 va_list args;
112
113 if (level > jbd2_journal_enable_debug)
114 return;
115 va_start(args, fmt);
116 vaf.fmt = fmt;
117 vaf.va = &args;
118 printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf);
119 va_end(args);
120}
121EXPORT_SYMBOL(__jbd2_debug);
122#endif
123
124/* Checksumming functions */
125static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
126{
127 if (!jbd2_journal_has_csum_v2or3_feature(j))
128 return 1;
129
130 return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
131}
132
133static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
134{
135 __u32 csum;
136 __be32 old_csum;
137
138 old_csum = sb->s_checksum;
139 sb->s_checksum = 0;
140 csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
141 sb->s_checksum = old_csum;
142
143 return cpu_to_be32(csum);
144}
145
146static int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
147{
148 if (!jbd2_journal_has_csum_v2or3(j))
149 return 1;
150
151 return sb->s_checksum == jbd2_superblock_csum(j, sb);
152}
153
154static void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
155{
156 if (!jbd2_journal_has_csum_v2or3(j))
157 return;
158
159 sb->s_checksum = jbd2_superblock_csum(j, sb);
160}
161
162/*
163 * Helper function used to manage commit timeouts
164 */
165
166static void commit_timeout(unsigned long __data)
167{
168 struct task_struct * p = (struct task_struct *) __data;
169
170 wake_up_process(p);
171}
172
173/*
174 * kjournald2: The main thread function used to manage a logging device
175 * journal.
176 *
177 * This kernel thread is responsible for two things:
178 *
179 * 1) COMMIT: Every so often we need to commit the current state of the
180 * filesystem to disk. The journal thread is responsible for writing
181 * all of the metadata buffers to disk.
182 *
183 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
184 * of the data in that part of the log has been rewritten elsewhere on
185 * the disk. Flushing these old buffers to reclaim space in the log is
186 * known as checkpointing, and this thread is responsible for that job.
187 */
188
189static int kjournald2(void *arg)
190{
191 journal_t *journal = arg;
192 transaction_t *transaction;
193
194 /*
195 * Set up an interval timer which can be used to trigger a commit wakeup
196 * after the commit interval expires
197 */
198 setup_timer(&journal->j_commit_timer, commit_timeout,
199 (unsigned long)current);
200
201 set_freezable();
202
203 /* Record that the journal thread is running */
204 journal->j_task = current;
205 wake_up(&journal->j_wait_done_commit);
206
207 /*
208 * And now, wait forever for commit wakeup events.
209 */
210 write_lock(&journal->j_state_lock);
211
212loop:
213 if (journal->j_flags & JBD2_UNMOUNT)
214 goto end_loop;
215
216 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
217 journal->j_commit_sequence, journal->j_commit_request);
218
219 if (journal->j_commit_sequence != journal->j_commit_request) {
220 jbd_debug(1, "OK, requests differ\n");
221 write_unlock(&journal->j_state_lock);
222 del_timer_sync(&journal->j_commit_timer);
223 jbd2_journal_commit_transaction(journal);
224 write_lock(&journal->j_state_lock);
225 goto loop;
226 }
227
228 wake_up(&journal->j_wait_done_commit);
229 if (freezing(current)) {
230 /*
231 * The simpler the better. Flushing journal isn't a
232 * good idea, because that depends on threads that may
233 * be already stopped.
234 */
235 jbd_debug(1, "Now suspending kjournald2\n");
236 write_unlock(&journal->j_state_lock);
237 try_to_freeze();
238 write_lock(&journal->j_state_lock);
239 } else {
240 /*
241 * We assume on resume that commits are already there,
242 * so we don't sleep
243 */
244 DEFINE_WAIT(wait);
245 int should_sleep = 1;
246
247 prepare_to_wait(&journal->j_wait_commit, &wait,
248 TASK_INTERRUPTIBLE);
249 if (journal->j_commit_sequence != journal->j_commit_request)
250 should_sleep = 0;
251 transaction = journal->j_running_transaction;
252 if (transaction && time_after_eq(jiffies,
253 transaction->t_expires))
254 should_sleep = 0;
255 if (journal->j_flags & JBD2_UNMOUNT)
256 should_sleep = 0;
257 if (should_sleep) {
258 write_unlock(&journal->j_state_lock);
259 schedule();
260 write_lock(&journal->j_state_lock);
261 }
262 finish_wait(&journal->j_wait_commit, &wait);
263 }
264
265 jbd_debug(1, "kjournald2 wakes\n");
266
267 /*
268 * Were we woken up by a commit wakeup event?
269 */
270 transaction = journal->j_running_transaction;
271 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
272 journal->j_commit_request = transaction->t_tid;
273 jbd_debug(1, "woke because of timeout\n");
274 }
275 goto loop;
276
277end_loop:
278 write_unlock(&journal->j_state_lock);
279 del_timer_sync(&journal->j_commit_timer);
280 journal->j_task = NULL;
281 wake_up(&journal->j_wait_done_commit);
282 jbd_debug(1, "Journal thread exiting.\n");
283 return 0;
284}
285
286static int jbd2_journal_start_thread(journal_t *journal)
287{
288 struct task_struct *t;
289
290 t = kthread_run(kjournald2, journal, "jbd2/%s",
291 journal->j_devname);
292 if (IS_ERR(t))
293 return PTR_ERR(t);
294
295 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
296 return 0;
297}
298
299static void journal_kill_thread(journal_t *journal)
300{
301 write_lock(&journal->j_state_lock);
302 journal->j_flags |= JBD2_UNMOUNT;
303
304 while (journal->j_task) {
305 write_unlock(&journal->j_state_lock);
306 wake_up(&journal->j_wait_commit);
307 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
308 write_lock(&journal->j_state_lock);
309 }
310 write_unlock(&journal->j_state_lock);
311}
312
313/*
314 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
315 *
316 * Writes a metadata buffer to a given disk block. The actual IO is not
317 * performed but a new buffer_head is constructed which labels the data
318 * to be written with the correct destination disk block.
319 *
320 * Any magic-number escaping which needs to be done will cause a
321 * copy-out here. If the buffer happens to start with the
322 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
323 * magic number is only written to the log for descripter blocks. In
324 * this case, we copy the data and replace the first word with 0, and we
325 * return a result code which indicates that this buffer needs to be
326 * marked as an escaped buffer in the corresponding log descriptor
327 * block. The missing word can then be restored when the block is read
328 * during recovery.
329 *
330 * If the source buffer has already been modified by a new transaction
331 * since we took the last commit snapshot, we use the frozen copy of
332 * that data for IO. If we end up using the existing buffer_head's data
333 * for the write, then we have to make sure nobody modifies it while the
334 * IO is in progress. do_get_write_access() handles this.
335 *
336 * The function returns a pointer to the buffer_head to be used for IO.
337 *
338 *
339 * Return value:
340 * <0: Error
341 * >=0: Finished OK
342 *
343 * On success:
344 * Bit 0 set == escape performed on the data
345 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
346 */
347
348int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
349 struct journal_head *jh_in,
350 struct buffer_head **bh_out,
351 sector_t blocknr)
352{
353 int need_copy_out = 0;
354 int done_copy_out = 0;
355 int do_escape = 0;
356 char *mapped_data;
357 struct buffer_head *new_bh;
358 struct page *new_page;
359 unsigned int new_offset;
360 struct buffer_head *bh_in = jh2bh(jh_in);
361 journal_t *journal = transaction->t_journal;
362
363 /*
364 * The buffer really shouldn't be locked: only the current committing
365 * transaction is allowed to write it, so nobody else is allowed
366 * to do any IO.
367 *
368 * akpm: except if we're journalling data, and write() output is
369 * also part of a shared mapping, and another thread has
370 * decided to launch a writepage() against this buffer.
371 */
372 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
373
374 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
375
376 /* keep subsequent assertions sane */
377 atomic_set(&new_bh->b_count, 1);
378
379 jbd_lock_bh_state(bh_in);
380repeat:
381 /*
382 * If a new transaction has already done a buffer copy-out, then
383 * we use that version of the data for the commit.
384 */
385 if (jh_in->b_frozen_data) {
386 done_copy_out = 1;
387 new_page = virt_to_page(jh_in->b_frozen_data);
388 new_offset = offset_in_page(jh_in->b_frozen_data);
389 } else {
390 new_page = jh2bh(jh_in)->b_page;
391 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
392 }
393
394 mapped_data = kmap_atomic(new_page);
395 /*
396 * Fire data frozen trigger if data already wasn't frozen. Do this
397 * before checking for escaping, as the trigger may modify the magic
398 * offset. If a copy-out happens afterwards, it will have the correct
399 * data in the buffer.
400 */
401 if (!done_copy_out)
402 jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
403 jh_in->b_triggers);
404
405 /*
406 * Check for escaping
407 */
408 if (*((__be32 *)(mapped_data + new_offset)) ==
409 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
410 need_copy_out = 1;
411 do_escape = 1;
412 }
413 kunmap_atomic(mapped_data);
414
415 /*
416 * Do we need to do a data copy?
417 */
418 if (need_copy_out && !done_copy_out) {
419 char *tmp;
420
421 jbd_unlock_bh_state(bh_in);
422 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
423 if (!tmp) {
424 brelse(new_bh);
425 return -ENOMEM;
426 }
427 jbd_lock_bh_state(bh_in);
428 if (jh_in->b_frozen_data) {
429 jbd2_free(tmp, bh_in->b_size);
430 goto repeat;
431 }
432
433 jh_in->b_frozen_data = tmp;
434 mapped_data = kmap_atomic(new_page);
435 memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
436 kunmap_atomic(mapped_data);
437
438 new_page = virt_to_page(tmp);
439 new_offset = offset_in_page(tmp);
440 done_copy_out = 1;
441
442 /*
443 * This isn't strictly necessary, as we're using frozen
444 * data for the escaping, but it keeps consistency with
445 * b_frozen_data usage.
446 */
447 jh_in->b_frozen_triggers = jh_in->b_triggers;
448 }
449
450 /*
451 * Did we need to do an escaping? Now we've done all the
452 * copying, we can finally do so.
453 */
454 if (do_escape) {
455 mapped_data = kmap_atomic(new_page);
456 *((unsigned int *)(mapped_data + new_offset)) = 0;
457 kunmap_atomic(mapped_data);
458 }
459
460 set_bh_page(new_bh, new_page, new_offset);
461 new_bh->b_size = bh_in->b_size;
462 new_bh->b_bdev = journal->j_dev;
463 new_bh->b_blocknr = blocknr;
464 new_bh->b_private = bh_in;
465 set_buffer_mapped(new_bh);
466 set_buffer_dirty(new_bh);
467
468 *bh_out = new_bh;
469
470 /*
471 * The to-be-written buffer needs to get moved to the io queue,
472 * and the original buffer whose contents we are shadowing or
473 * copying is moved to the transaction's shadow queue.
474 */
475 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
476 spin_lock(&journal->j_list_lock);
477 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
478 spin_unlock(&journal->j_list_lock);
479 set_buffer_shadow(bh_in);
480 jbd_unlock_bh_state(bh_in);
481
482 return do_escape | (done_copy_out << 1);
483}
484
485/*
486 * Allocation code for the journal file. Manage the space left in the
487 * journal, so that we can begin checkpointing when appropriate.
488 */
489
490/*
491 * Called with j_state_lock locked for writing.
492 * Returns true if a transaction commit was started.
493 */
494int __jbd2_log_start_commit(journal_t *journal, tid_t target)
495{
496 /* Return if the txn has already requested to be committed */
497 if (journal->j_commit_request == target)
498 return 0;
499
500 /*
501 * The only transaction we can possibly wait upon is the
502 * currently running transaction (if it exists). Otherwise,
503 * the target tid must be an old one.
504 */
505 if (journal->j_running_transaction &&
506 journal->j_running_transaction->t_tid == target) {
507 /*
508 * We want a new commit: OK, mark the request and wakeup the
509 * commit thread. We do _not_ do the commit ourselves.
510 */
511
512 journal->j_commit_request = target;
513 jbd_debug(1, "JBD2: requesting commit %d/%d\n",
514 journal->j_commit_request,
515 journal->j_commit_sequence);
516 journal->j_running_transaction->t_requested = jiffies;
517 wake_up(&journal->j_wait_commit);
518 return 1;
519 } else if (!tid_geq(journal->j_commit_request, target))
520 /* This should never happen, but if it does, preserve
521 the evidence before kjournald goes into a loop and
522 increments j_commit_sequence beyond all recognition. */
523 WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
524 journal->j_commit_request,
525 journal->j_commit_sequence,
526 target, journal->j_running_transaction ?
527 journal->j_running_transaction->t_tid : 0);
528 return 0;
529}
530
531int jbd2_log_start_commit(journal_t *journal, tid_t tid)
532{
533 int ret;
534
535 write_lock(&journal->j_state_lock);
536 ret = __jbd2_log_start_commit(journal, tid);
537 write_unlock(&journal->j_state_lock);
538 return ret;
539}
540
541/*
542 * Force and wait any uncommitted transactions. We can only force the running
543 * transaction if we don't have an active handle, otherwise, we will deadlock.
544 * Returns: <0 in case of error,
545 * 0 if nothing to commit,
546 * 1 if transaction was successfully committed.
547 */
548static int __jbd2_journal_force_commit(journal_t *journal)
549{
550 transaction_t *transaction = NULL;
551 tid_t tid;
552 int need_to_start = 0, ret = 0;
553
554 read_lock(&journal->j_state_lock);
555 if (journal->j_running_transaction && !current->journal_info) {
556 transaction = journal->j_running_transaction;
557 if (!tid_geq(journal->j_commit_request, transaction->t_tid))
558 need_to_start = 1;
559 } else if (journal->j_committing_transaction)
560 transaction = journal->j_committing_transaction;
561
562 if (!transaction) {
563 /* Nothing to commit */
564 read_unlock(&journal->j_state_lock);
565 return 0;
566 }
567 tid = transaction->t_tid;
568 read_unlock(&journal->j_state_lock);
569 if (need_to_start)
570 jbd2_log_start_commit(journal, tid);
571 ret = jbd2_log_wait_commit(journal, tid);
572 if (!ret)
573 ret = 1;
574
575 return ret;
576}
577
578/**
579 * Force and wait upon a commit if the calling process is not within
580 * transaction. This is used for forcing out undo-protected data which contains
581 * bitmaps, when the fs is running out of space.
582 *
583 * @journal: journal to force
584 * Returns true if progress was made.
585 */
586int jbd2_journal_force_commit_nested(journal_t *journal)
587{
588 int ret;
589
590 ret = __jbd2_journal_force_commit(journal);
591 return ret > 0;
592}
593
594/**
595 * int journal_force_commit() - force any uncommitted transactions
596 * @journal: journal to force
597 *
598 * Caller want unconditional commit. We can only force the running transaction
599 * if we don't have an active handle, otherwise, we will deadlock.
600 */
601int jbd2_journal_force_commit(journal_t *journal)
602{
603 int ret;
604
605 J_ASSERT(!current->journal_info);
606 ret = __jbd2_journal_force_commit(journal);
607 if (ret > 0)
608 ret = 0;
609 return ret;
610}
611
612/*
613 * Start a commit of the current running transaction (if any). Returns true
614 * if a transaction is going to be committed (or is currently already
615 * committing), and fills its tid in at *ptid
616 */
617int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
618{
619 int ret = 0;
620
621 write_lock(&journal->j_state_lock);
622 if (journal->j_running_transaction) {
623 tid_t tid = journal->j_running_transaction->t_tid;
624
625 __jbd2_log_start_commit(journal, tid);
626 /* There's a running transaction and we've just made sure
627 * it's commit has been scheduled. */
628 if (ptid)
629 *ptid = tid;
630 ret = 1;
631 } else if (journal->j_committing_transaction) {
632 /*
633 * If commit has been started, then we have to wait for
634 * completion of that transaction.
635 */
636 if (ptid)
637 *ptid = journal->j_committing_transaction->t_tid;
638 ret = 1;
639 }
640 write_unlock(&journal->j_state_lock);
641 return ret;
642}
643
644/*
645 * Return 1 if a given transaction has not yet sent barrier request
646 * connected with a transaction commit. If 0 is returned, transaction
647 * may or may not have sent the barrier. Used to avoid sending barrier
648 * twice in common cases.
649 */
650int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
651{
652 int ret = 0;
653 transaction_t *commit_trans;
654
655 if (!(journal->j_flags & JBD2_BARRIER))
656 return 0;
657 read_lock(&journal->j_state_lock);
658 /* Transaction already committed? */
659 if (tid_geq(journal->j_commit_sequence, tid))
660 goto out;
661 commit_trans = journal->j_committing_transaction;
662 if (!commit_trans || commit_trans->t_tid != tid) {
663 ret = 1;
664 goto out;
665 }
666 /*
667 * Transaction is being committed and we already proceeded to
668 * submitting a flush to fs partition?
669 */
670 if (journal->j_fs_dev != journal->j_dev) {
671 if (!commit_trans->t_need_data_flush ||
672 commit_trans->t_state >= T_COMMIT_DFLUSH)
673 goto out;
674 } else {
675 if (commit_trans->t_state >= T_COMMIT_JFLUSH)
676 goto out;
677 }
678 ret = 1;
679out:
680 read_unlock(&journal->j_state_lock);
681 return ret;
682}
683EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
684
685/*
686 * Wait for a specified commit to complete.
687 * The caller may not hold the journal lock.
688 */
689int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
690{
691 int err = 0;
692
693 read_lock(&journal->j_state_lock);
694#ifdef CONFIG_JBD2_DEBUG
695 if (!tid_geq(journal->j_commit_request, tid)) {
696 printk(KERN_ERR
697 "%s: error: j_commit_request=%d, tid=%d\n",
698 __func__, journal->j_commit_request, tid);
699 }
700#endif
701 while (tid_gt(tid, journal->j_commit_sequence)) {
702 jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
703 tid, journal->j_commit_sequence);
704 read_unlock(&journal->j_state_lock);
705 wake_up(&journal->j_wait_commit);
706 wait_event(journal->j_wait_done_commit,
707 !tid_gt(tid, journal->j_commit_sequence));
708 read_lock(&journal->j_state_lock);
709 }
710 read_unlock(&journal->j_state_lock);
711
712 if (unlikely(is_journal_aborted(journal)))
713 err = -EIO;
714 return err;
715}
716
717/*
718 * When this function returns the transaction corresponding to tid
719 * will be completed. If the transaction has currently running, start
720 * committing that transaction before waiting for it to complete. If
721 * the transaction id is stale, it is by definition already completed,
722 * so just return SUCCESS.
723 */
724int jbd2_complete_transaction(journal_t *journal, tid_t tid)
725{
726 int need_to_wait = 1;
727
728 read_lock(&journal->j_state_lock);
729 if (journal->j_running_transaction &&
730 journal->j_running_transaction->t_tid == tid) {
731 if (journal->j_commit_request != tid) {
732 /* transaction not yet started, so request it */
733 read_unlock(&journal->j_state_lock);
734 jbd2_log_start_commit(journal, tid);
735 goto wait_commit;
736 }
737 } else if (!(journal->j_committing_transaction &&
738 journal->j_committing_transaction->t_tid == tid))
739 need_to_wait = 0;
740 read_unlock(&journal->j_state_lock);
741 if (!need_to_wait)
742 return 0;
743wait_commit:
744 return jbd2_log_wait_commit(journal, tid);
745}
746EXPORT_SYMBOL(jbd2_complete_transaction);
747
748/*
749 * Log buffer allocation routines:
750 */
751
752int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
753{
754 unsigned long blocknr;
755
756 write_lock(&journal->j_state_lock);
757 J_ASSERT(journal->j_free > 1);
758
759 blocknr = journal->j_head;
760 journal->j_head++;
761 journal->j_free--;
762 if (journal->j_head == journal->j_last)
763 journal->j_head = journal->j_first;
764 write_unlock(&journal->j_state_lock);
765 return jbd2_journal_bmap(journal, blocknr, retp);
766}
767
768/*
769 * Conversion of logical to physical block numbers for the journal
770 *
771 * On external journals the journal blocks are identity-mapped, so
772 * this is a no-op. If needed, we can use j_blk_offset - everything is
773 * ready.
774 */
775int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
776 unsigned long long *retp)
777{
778 int err = 0;
779 unsigned long long ret;
780
781 if (journal->j_inode) {
782 ret = bmap(journal->j_inode, blocknr);
783 if (ret)
784 *retp = ret;
785 else {
786 printk(KERN_ALERT "%s: journal block not found "
787 "at offset %lu on %s\n",
788 __func__, blocknr, journal->j_devname);
789 err = -EIO;
790 __journal_abort_soft(journal, err);
791 }
792 } else {
793 *retp = blocknr; /* +journal->j_blk_offset */
794 }
795 return err;
796}
797
798/*
799 * We play buffer_head aliasing tricks to write data/metadata blocks to
800 * the journal without copying their contents, but for journal
801 * descriptor blocks we do need to generate bona fide buffers.
802 *
803 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
804 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
805 * But we don't bother doing that, so there will be coherency problems with
806 * mmaps of blockdevs which hold live JBD-controlled filesystems.
807 */
808struct buffer_head *
809jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
810{
811 journal_t *journal = transaction->t_journal;
812 struct buffer_head *bh;
813 unsigned long long blocknr;
814 journal_header_t *header;
815 int err;
816
817 err = jbd2_journal_next_log_block(journal, &blocknr);
818
819 if (err)
820 return NULL;
821
822 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
823 if (!bh)
824 return NULL;
825 lock_buffer(bh);
826 memset(bh->b_data, 0, journal->j_blocksize);
827 header = (journal_header_t *)bh->b_data;
828 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
829 header->h_blocktype = cpu_to_be32(type);
830 header->h_sequence = cpu_to_be32(transaction->t_tid);
831 set_buffer_uptodate(bh);
832 unlock_buffer(bh);
833 BUFFER_TRACE(bh, "return this buffer");
834 return bh;
835}
836
837void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
838{
839 struct jbd2_journal_block_tail *tail;
840 __u32 csum;
841
842 if (!jbd2_journal_has_csum_v2or3(j))
843 return;
844
845 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
846 sizeof(struct jbd2_journal_block_tail));
847 tail->t_checksum = 0;
848 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
849 tail->t_checksum = cpu_to_be32(csum);
850}
851
852/*
853 * Return tid of the oldest transaction in the journal and block in the journal
854 * where the transaction starts.
855 *
856 * If the journal is now empty, return which will be the next transaction ID
857 * we will write and where will that transaction start.
858 *
859 * The return value is 0 if journal tail cannot be pushed any further, 1 if
860 * it can.
861 */
862int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
863 unsigned long *block)
864{
865 transaction_t *transaction;
866 int ret;
867
868 read_lock(&journal->j_state_lock);
869 spin_lock(&journal->j_list_lock);
870 transaction = journal->j_checkpoint_transactions;
871 if (transaction) {
872 *tid = transaction->t_tid;
873 *block = transaction->t_log_start;
874 } else if ((transaction = journal->j_committing_transaction) != NULL) {
875 *tid = transaction->t_tid;
876 *block = transaction->t_log_start;
877 } else if ((transaction = journal->j_running_transaction) != NULL) {
878 *tid = transaction->t_tid;
879 *block = journal->j_head;
880 } else {
881 *tid = journal->j_transaction_sequence;
882 *block = journal->j_head;
883 }
884 ret = tid_gt(*tid, journal->j_tail_sequence);
885 spin_unlock(&journal->j_list_lock);
886 read_unlock(&journal->j_state_lock);
887
888 return ret;
889}
890
891/*
892 * Update information in journal structure and in on disk journal superblock
893 * about log tail. This function does not check whether information passed in
894 * really pushes log tail further. It's responsibility of the caller to make
895 * sure provided log tail information is valid (e.g. by holding
896 * j_checkpoint_mutex all the time between computing log tail and calling this
897 * function as is the case with jbd2_cleanup_journal_tail()).
898 *
899 * Requires j_checkpoint_mutex
900 */
901int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
902{
903 unsigned long freed;
904 int ret;
905
906 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
907
908 /*
909 * We cannot afford for write to remain in drive's caches since as
910 * soon as we update j_tail, next transaction can start reusing journal
911 * space and if we lose sb update during power failure we'd replay
912 * old transaction with possibly newly overwritten data.
913 */
914 ret = jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
915 if (ret)
916 goto out;
917
918 write_lock(&journal->j_state_lock);
919 freed = block - journal->j_tail;
920 if (block < journal->j_tail)
921 freed += journal->j_last - journal->j_first;
922
923 trace_jbd2_update_log_tail(journal, tid, block, freed);
924 jbd_debug(1,
925 "Cleaning journal tail from %d to %d (offset %lu), "
926 "freeing %lu\n",
927 journal->j_tail_sequence, tid, block, freed);
928
929 journal->j_free += freed;
930 journal->j_tail_sequence = tid;
931 journal->j_tail = block;
932 write_unlock(&journal->j_state_lock);
933
934out:
935 return ret;
936}
937
938/*
939 * This is a variaon of __jbd2_update_log_tail which checks for validity of
940 * provided log tail and locks j_checkpoint_mutex. So it is safe against races
941 * with other threads updating log tail.
942 */
943void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
944{
945 mutex_lock(&journal->j_checkpoint_mutex);
946 if (tid_gt(tid, journal->j_tail_sequence))
947 __jbd2_update_log_tail(journal, tid, block);
948 mutex_unlock(&journal->j_checkpoint_mutex);
949}
950
951struct jbd2_stats_proc_session {
952 journal_t *journal;
953 struct transaction_stats_s *stats;
954 int start;
955 int max;
956};
957
958static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
959{
960 return *pos ? NULL : SEQ_START_TOKEN;
961}
962
963static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
964{
965 return NULL;
966}
967
968static int jbd2_seq_info_show(struct seq_file *seq, void *v)
969{
970 struct jbd2_stats_proc_session *s = seq->private;
971
972 if (v != SEQ_START_TOKEN)
973 return 0;
974 seq_printf(seq, "%lu transactions (%lu requested), "
975 "each up to %u blocks\n",
976 s->stats->ts_tid, s->stats->ts_requested,
977 s->journal->j_max_transaction_buffers);
978 if (s->stats->ts_tid == 0)
979 return 0;
980 seq_printf(seq, "average: \n %ums waiting for transaction\n",
981 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
982 seq_printf(seq, " %ums request delay\n",
983 (s->stats->ts_requested == 0) ? 0 :
984 jiffies_to_msecs(s->stats->run.rs_request_delay /
985 s->stats->ts_requested));
986 seq_printf(seq, " %ums running transaction\n",
987 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
988 seq_printf(seq, " %ums transaction was being locked\n",
989 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
990 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
991 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
992 seq_printf(seq, " %ums logging transaction\n",
993 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
994 seq_printf(seq, " %lluus average transaction commit time\n",
995 div_u64(s->journal->j_average_commit_time, 1000));
996 seq_printf(seq, " %lu handles per transaction\n",
997 s->stats->run.rs_handle_count / s->stats->ts_tid);
998 seq_printf(seq, " %lu blocks per transaction\n",
999 s->stats->run.rs_blocks / s->stats->ts_tid);
1000 seq_printf(seq, " %lu logged blocks per transaction\n",
1001 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1002 return 0;
1003}
1004
1005static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1006{
1007}
1008
1009static const struct seq_operations jbd2_seq_info_ops = {
1010 .start = jbd2_seq_info_start,
1011 .next = jbd2_seq_info_next,
1012 .stop = jbd2_seq_info_stop,
1013 .show = jbd2_seq_info_show,
1014};
1015
1016static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1017{
1018 journal_t *journal = PDE_DATA(inode);
1019 struct jbd2_stats_proc_session *s;
1020 int rc, size;
1021
1022 s = kmalloc(sizeof(*s), GFP_KERNEL);
1023 if (s == NULL)
1024 return -ENOMEM;
1025 size = sizeof(struct transaction_stats_s);
1026 s->stats = kmalloc(size, GFP_KERNEL);
1027 if (s->stats == NULL) {
1028 kfree(s);
1029 return -ENOMEM;
1030 }
1031 spin_lock(&journal->j_history_lock);
1032 memcpy(s->stats, &journal->j_stats, size);
1033 s->journal = journal;
1034 spin_unlock(&journal->j_history_lock);
1035
1036 rc = seq_open(file, &jbd2_seq_info_ops);
1037 if (rc == 0) {
1038 struct seq_file *m = file->private_data;
1039 m->private = s;
1040 } else {
1041 kfree(s->stats);
1042 kfree(s);
1043 }
1044 return rc;
1045
1046}
1047
1048static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1049{
1050 struct seq_file *seq = file->private_data;
1051 struct jbd2_stats_proc_session *s = seq->private;
1052 kfree(s->stats);
1053 kfree(s);
1054 return seq_release(inode, file);
1055}
1056
1057static const struct file_operations jbd2_seq_info_fops = {
1058 .owner = THIS_MODULE,
1059 .open = jbd2_seq_info_open,
1060 .read = seq_read,
1061 .llseek = seq_lseek,
1062 .release = jbd2_seq_info_release,
1063};
1064
1065static struct proc_dir_entry *proc_jbd2_stats;
1066
1067static void jbd2_stats_proc_init(journal_t *journal)
1068{
1069 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1070 if (journal->j_proc_entry) {
1071 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1072 &jbd2_seq_info_fops, journal);
1073 }
1074}
1075
1076static void jbd2_stats_proc_exit(journal_t *journal)
1077{
1078 remove_proc_entry("info", journal->j_proc_entry);
1079 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1080}
1081
1082/*
1083 * Management for journal control blocks: functions to create and
1084 * destroy journal_t structures, and to initialise and read existing
1085 * journal blocks from disk. */
1086
1087/* First: create and setup a journal_t object in memory. We initialise
1088 * very few fields yet: that has to wait until we have created the
1089 * journal structures from from scratch, or loaded them from disk. */
1090
1091static journal_t * journal_init_common (void)
1092{
1093 journal_t *journal;
1094 int err;
1095
1096 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1097 if (!journal)
1098 return NULL;
1099
1100 init_waitqueue_head(&journal->j_wait_transaction_locked);
1101 init_waitqueue_head(&journal->j_wait_done_commit);
1102 init_waitqueue_head(&journal->j_wait_commit);
1103 init_waitqueue_head(&journal->j_wait_updates);
1104 init_waitqueue_head(&journal->j_wait_reserved);
1105 mutex_init(&journal->j_barrier);
1106 mutex_init(&journal->j_checkpoint_mutex);
1107 spin_lock_init(&journal->j_revoke_lock);
1108 spin_lock_init(&journal->j_list_lock);
1109 rwlock_init(&journal->j_state_lock);
1110
1111 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1112 journal->j_min_batch_time = 0;
1113 journal->j_max_batch_time = 15000; /* 15ms */
1114 atomic_set(&journal->j_reserved_credits, 0);
1115
1116 /* The journal is marked for error until we succeed with recovery! */
1117 journal->j_flags = JBD2_ABORT;
1118
1119 /* Set up a default-sized revoke table for the new mount. */
1120 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1121 if (err) {
1122 kfree(journal);
1123 return NULL;
1124 }
1125
1126 spin_lock_init(&journal->j_history_lock);
1127
1128 return journal;
1129}
1130
1131/* jbd2_journal_init_dev and jbd2_journal_init_inode:
1132 *
1133 * Create a journal structure assigned some fixed set of disk blocks to
1134 * the journal. We don't actually touch those disk blocks yet, but we
1135 * need to set up all of the mapping information to tell the journaling
1136 * system where the journal blocks are.
1137 *
1138 */
1139
1140/**
1141 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1142 * @bdev: Block device on which to create the journal
1143 * @fs_dev: Device which hold journalled filesystem for this journal.
1144 * @start: Block nr Start of journal.
1145 * @len: Length of the journal in blocks.
1146 * @blocksize: blocksize of journalling device
1147 *
1148 * Returns: a newly created journal_t *
1149 *
1150 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1151 * range of blocks on an arbitrary block device.
1152 *
1153 */
1154journal_t * jbd2_journal_init_dev(struct block_device *bdev,
1155 struct block_device *fs_dev,
1156 unsigned long long start, int len, int blocksize)
1157{
1158 journal_t *journal = journal_init_common();
1159 struct buffer_head *bh;
1160 int n;
1161
1162 if (!journal)
1163 return NULL;
1164
1165 /* journal descriptor can store up to n blocks -bzzz */
1166 journal->j_blocksize = blocksize;
1167 journal->j_dev = bdev;
1168 journal->j_fs_dev = fs_dev;
1169 journal->j_blk_offset = start;
1170 journal->j_maxlen = len;
1171 bdevname(journal->j_dev, journal->j_devname);
1172 strreplace(journal->j_devname, '/', '!');
1173 jbd2_stats_proc_init(journal);
1174 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1175 journal->j_wbufsize = n;
1176 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1177 if (!journal->j_wbuf) {
1178 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1179 __func__);
1180 goto out_err;
1181 }
1182
1183 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
1184 if (!bh) {
1185 printk(KERN_ERR
1186 "%s: Cannot get buffer for journal superblock\n",
1187 __func__);
1188 goto out_err;
1189 }
1190 journal->j_sb_buffer = bh;
1191 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1192
1193 return journal;
1194out_err:
1195 kfree(journal->j_wbuf);
1196 jbd2_stats_proc_exit(journal);
1197 kfree(journal);
1198 return NULL;
1199}
1200
1201/**
1202 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1203 * @inode: An inode to create the journal in
1204 *
1205 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1206 * the journal. The inode must exist already, must support bmap() and
1207 * must have all data blocks preallocated.
1208 */
1209journal_t * jbd2_journal_init_inode (struct inode *inode)
1210{
1211 struct buffer_head *bh;
1212 journal_t *journal = journal_init_common();
1213 char *p;
1214 int err;
1215 int n;
1216 unsigned long long blocknr;
1217
1218 if (!journal)
1219 return NULL;
1220
1221 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
1222 journal->j_inode = inode;
1223 bdevname(journal->j_dev, journal->j_devname);
1224 p = strreplace(journal->j_devname, '/', '!');
1225 sprintf(p, "-%lu", journal->j_inode->i_ino);
1226 jbd_debug(1,
1227 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
1228 journal, inode->i_sb->s_id, inode->i_ino,
1229 (long long) inode->i_size,
1230 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1231
1232 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
1233 journal->j_blocksize = inode->i_sb->s_blocksize;
1234 jbd2_stats_proc_init(journal);
1235
1236 /* journal descriptor can store up to n blocks -bzzz */
1237 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1238 journal->j_wbufsize = n;
1239 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1240 if (!journal->j_wbuf) {
1241 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1242 __func__);
1243 goto out_err;
1244 }
1245
1246 err = jbd2_journal_bmap(journal, 0, &blocknr);
1247 /* If that failed, give up */
1248 if (err) {
1249 printk(KERN_ERR "%s: Cannot locate journal superblock\n",
1250 __func__);
1251 goto out_err;
1252 }
1253
1254 bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize);
1255 if (!bh) {
1256 printk(KERN_ERR
1257 "%s: Cannot get buffer for journal superblock\n",
1258 __func__);
1259 goto out_err;
1260 }
1261 journal->j_sb_buffer = bh;
1262 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1263
1264 return journal;
1265out_err:
1266 kfree(journal->j_wbuf);
1267 jbd2_stats_proc_exit(journal);
1268 kfree(journal);
1269 return NULL;
1270}
1271
1272/*
1273 * If the journal init or create aborts, we need to mark the journal
1274 * superblock as being NULL to prevent the journal destroy from writing
1275 * back a bogus superblock.
1276 */
1277static void journal_fail_superblock (journal_t *journal)
1278{
1279 struct buffer_head *bh = journal->j_sb_buffer;
1280 brelse(bh);
1281 journal->j_sb_buffer = NULL;
1282}
1283
1284/*
1285 * Given a journal_t structure, initialise the various fields for
1286 * startup of a new journaling session. We use this both when creating
1287 * a journal, and after recovering an old journal to reset it for
1288 * subsequent use.
1289 */
1290
1291static int journal_reset(journal_t *journal)
1292{
1293 journal_superblock_t *sb = journal->j_superblock;
1294 unsigned long long first, last;
1295
1296 first = be32_to_cpu(sb->s_first);
1297 last = be32_to_cpu(sb->s_maxlen);
1298 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1299 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1300 first, last);
1301 journal_fail_superblock(journal);
1302 return -EINVAL;
1303 }
1304
1305 journal->j_first = first;
1306 journal->j_last = last;
1307
1308 journal->j_head = first;
1309 journal->j_tail = first;
1310 journal->j_free = last - first;
1311
1312 journal->j_tail_sequence = journal->j_transaction_sequence;
1313 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1314 journal->j_commit_request = journal->j_commit_sequence;
1315
1316 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1317
1318 /*
1319 * As a special case, if the on-disk copy is already marked as needing
1320 * no recovery (s_start == 0), then we can safely defer the superblock
1321 * update until the next commit by setting JBD2_FLUSHED. This avoids
1322 * attempting a write to a potential-readonly device.
1323 */
1324 if (sb->s_start == 0) {
1325 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1326 "(start %ld, seq %d, errno %d)\n",
1327 journal->j_tail, journal->j_tail_sequence,
1328 journal->j_errno);
1329 journal->j_flags |= JBD2_FLUSHED;
1330 } else {
1331 /* Lock here to make assertions happy... */
1332 mutex_lock(&journal->j_checkpoint_mutex);
1333 /*
1334 * Update log tail information. We use WRITE_FUA since new
1335 * transaction will start reusing journal space and so we
1336 * must make sure information about current log tail is on
1337 * disk before that.
1338 */
1339 jbd2_journal_update_sb_log_tail(journal,
1340 journal->j_tail_sequence,
1341 journal->j_tail,
1342 WRITE_FUA);
1343 mutex_unlock(&journal->j_checkpoint_mutex);
1344 }
1345 return jbd2_journal_start_thread(journal);
1346}
1347
1348static int jbd2_write_superblock(journal_t *journal, int write_op)
1349{
1350 struct buffer_head *bh = journal->j_sb_buffer;
1351 journal_superblock_t *sb = journal->j_superblock;
1352 int ret;
1353
1354 trace_jbd2_write_superblock(journal, write_op);
1355 if (!(journal->j_flags & JBD2_BARRIER))
1356 write_op &= ~(REQ_FUA | REQ_FLUSH);
1357 lock_buffer(bh);
1358 if (buffer_write_io_error(bh)) {
1359 /*
1360 * Oh, dear. A previous attempt to write the journal
1361 * superblock failed. This could happen because the
1362 * USB device was yanked out. Or it could happen to
1363 * be a transient write error and maybe the block will
1364 * be remapped. Nothing we can do but to retry the
1365 * write and hope for the best.
1366 */
1367 printk(KERN_ERR "JBD2: previous I/O error detected "
1368 "for journal superblock update for %s.\n",
1369 journal->j_devname);
1370 clear_buffer_write_io_error(bh);
1371 set_buffer_uptodate(bh);
1372 }
1373 jbd2_superblock_csum_set(journal, sb);
1374 get_bh(bh);
1375 bh->b_end_io = end_buffer_write_sync;
1376 ret = submit_bh(write_op, bh);
1377 wait_on_buffer(bh);
1378 if (buffer_write_io_error(bh)) {
1379 clear_buffer_write_io_error(bh);
1380 set_buffer_uptodate(bh);
1381 ret = -EIO;
1382 }
1383 if (ret) {
1384 printk(KERN_ERR "JBD2: Error %d detected when updating "
1385 "journal superblock for %s.\n", ret,
1386 journal->j_devname);
1387 jbd2_journal_abort(journal, ret);
1388 }
1389
1390 return ret;
1391}
1392
1393/**
1394 * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1395 * @journal: The journal to update.
1396 * @tail_tid: TID of the new transaction at the tail of the log
1397 * @tail_block: The first block of the transaction at the tail of the log
1398 * @write_op: With which operation should we write the journal sb
1399 *
1400 * Update a journal's superblock information about log tail and write it to
1401 * disk, waiting for the IO to complete.
1402 */
1403int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1404 unsigned long tail_block, int write_op)
1405{
1406 journal_superblock_t *sb = journal->j_superblock;
1407 int ret;
1408
1409 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1410 jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1411 tail_block, tail_tid);
1412
1413 sb->s_sequence = cpu_to_be32(tail_tid);
1414 sb->s_start = cpu_to_be32(tail_block);
1415
1416 ret = jbd2_write_superblock(journal, write_op);
1417 if (ret)
1418 goto out;
1419
1420 /* Log is no longer empty */
1421 write_lock(&journal->j_state_lock);
1422 WARN_ON(!sb->s_sequence);
1423 journal->j_flags &= ~JBD2_FLUSHED;
1424 write_unlock(&journal->j_state_lock);
1425
1426out:
1427 return ret;
1428}
1429
1430/**
1431 * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1432 * @journal: The journal to update.
1433 * @write_op: With which operation should we write the journal sb
1434 *
1435 * Update a journal's dynamic superblock fields to show that journal is empty.
1436 * Write updated superblock to disk waiting for IO to complete.
1437 */
1438static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1439{
1440 journal_superblock_t *sb = journal->j_superblock;
1441
1442 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1443 read_lock(&journal->j_state_lock);
1444 /* Is it already empty? */
1445 if (sb->s_start == 0) {
1446 read_unlock(&journal->j_state_lock);
1447 return;
1448 }
1449 jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
1450 journal->j_tail_sequence);
1451
1452 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1453 sb->s_start = cpu_to_be32(0);
1454 read_unlock(&journal->j_state_lock);
1455
1456 jbd2_write_superblock(journal, write_op);
1457
1458 /* Log is no longer empty */
1459 write_lock(&journal->j_state_lock);
1460 journal->j_flags |= JBD2_FLUSHED;
1461 write_unlock(&journal->j_state_lock);
1462}
1463
1464
1465/**
1466 * jbd2_journal_update_sb_errno() - Update error in the journal.
1467 * @journal: The journal to update.
1468 *
1469 * Update a journal's errno. Write updated superblock to disk waiting for IO
1470 * to complete.
1471 */
1472void jbd2_journal_update_sb_errno(journal_t *journal)
1473{
1474 journal_superblock_t *sb = journal->j_superblock;
1475
1476 read_lock(&journal->j_state_lock);
1477 jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
1478 journal->j_errno);
1479 sb->s_errno = cpu_to_be32(journal->j_errno);
1480 read_unlock(&journal->j_state_lock);
1481
1482 jbd2_write_superblock(journal, WRITE_FUA);
1483}
1484EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1485
1486/*
1487 * Read the superblock for a given journal, performing initial
1488 * validation of the format.
1489 */
1490static int journal_get_superblock(journal_t *journal)
1491{
1492 struct buffer_head *bh;
1493 journal_superblock_t *sb;
1494 int err = -EIO;
1495
1496 bh = journal->j_sb_buffer;
1497
1498 J_ASSERT(bh != NULL);
1499 if (!buffer_uptodate(bh)) {
1500 ll_rw_block(READ, 1, &bh);
1501 wait_on_buffer(bh);
1502 if (!buffer_uptodate(bh)) {
1503 printk(KERN_ERR
1504 "JBD2: IO error reading journal superblock\n");
1505 goto out;
1506 }
1507 }
1508
1509 if (buffer_verified(bh))
1510 return 0;
1511
1512 sb = journal->j_superblock;
1513
1514 err = -EINVAL;
1515
1516 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1517 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1518 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1519 goto out;
1520 }
1521
1522 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1523 case JBD2_SUPERBLOCK_V1:
1524 journal->j_format_version = 1;
1525 break;
1526 case JBD2_SUPERBLOCK_V2:
1527 journal->j_format_version = 2;
1528 break;
1529 default:
1530 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1531 goto out;
1532 }
1533
1534 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1535 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1536 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1537 printk(KERN_WARNING "JBD2: journal file too short\n");
1538 goto out;
1539 }
1540
1541 if (be32_to_cpu(sb->s_first) == 0 ||
1542 be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
1543 printk(KERN_WARNING
1544 "JBD2: Invalid start block of journal: %u\n",
1545 be32_to_cpu(sb->s_first));
1546 goto out;
1547 }
1548
1549 if (jbd2_has_feature_csum2(journal) &&
1550 jbd2_has_feature_csum3(journal)) {
1551 /* Can't have checksum v2 and v3 at the same time! */
1552 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1553 "at the same time!\n");
1554 goto out;
1555 }
1556
1557 if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1558 jbd2_has_feature_checksum(journal)) {
1559 /* Can't have checksum v1 and v2 on at the same time! */
1560 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1561 "at the same time!\n");
1562 goto out;
1563 }
1564
1565 if (!jbd2_verify_csum_type(journal, sb)) {
1566 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1567 goto out;
1568 }
1569
1570 /* Load the checksum driver */
1571 if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1572 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1573 if (IS_ERR(journal->j_chksum_driver)) {
1574 printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1575 err = PTR_ERR(journal->j_chksum_driver);
1576 journal->j_chksum_driver = NULL;
1577 goto out;
1578 }
1579 }
1580
1581 /* Check superblock checksum */
1582 if (!jbd2_superblock_csum_verify(journal, sb)) {
1583 printk(KERN_ERR "JBD2: journal checksum error\n");
1584 err = -EFSBADCRC;
1585 goto out;
1586 }
1587
1588 /* Precompute checksum seed for all metadata */
1589 if (jbd2_journal_has_csum_v2or3(journal))
1590 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1591 sizeof(sb->s_uuid));
1592
1593 set_buffer_verified(bh);
1594
1595 return 0;
1596
1597out:
1598 journal_fail_superblock(journal);
1599 return err;
1600}
1601
1602/*
1603 * Load the on-disk journal superblock and read the key fields into the
1604 * journal_t.
1605 */
1606
1607static int load_superblock(journal_t *journal)
1608{
1609 int err;
1610 journal_superblock_t *sb;
1611
1612 err = journal_get_superblock(journal);
1613 if (err)
1614 return err;
1615
1616 sb = journal->j_superblock;
1617
1618 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1619 journal->j_tail = be32_to_cpu(sb->s_start);
1620 journal->j_first = be32_to_cpu(sb->s_first);
1621 journal->j_last = be32_to_cpu(sb->s_maxlen);
1622 journal->j_errno = be32_to_cpu(sb->s_errno);
1623
1624 return 0;
1625}
1626
1627
1628/**
1629 * int jbd2_journal_load() - Read journal from disk.
1630 * @journal: Journal to act on.
1631 *
1632 * Given a journal_t structure which tells us which disk blocks contain
1633 * a journal, read the journal from disk to initialise the in-memory
1634 * structures.
1635 */
1636int jbd2_journal_load(journal_t *journal)
1637{
1638 int err;
1639 journal_superblock_t *sb;
1640
1641 err = load_superblock(journal);
1642 if (err)
1643 return err;
1644
1645 sb = journal->j_superblock;
1646 /* If this is a V2 superblock, then we have to check the
1647 * features flags on it. */
1648
1649 if (journal->j_format_version >= 2) {
1650 if ((sb->s_feature_ro_compat &
1651 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1652 (sb->s_feature_incompat &
1653 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1654 printk(KERN_WARNING
1655 "JBD2: Unrecognised features on journal\n");
1656 return -EINVAL;
1657 }
1658 }
1659
1660 /*
1661 * Create a slab for this blocksize
1662 */
1663 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
1664 if (err)
1665 return err;
1666
1667 /* Let the recovery code check whether it needs to recover any
1668 * data from the journal. */
1669 if (jbd2_journal_recover(journal))
1670 goto recovery_error;
1671
1672 if (journal->j_failed_commit) {
1673 printk(KERN_ERR "JBD2: journal transaction %u on %s "
1674 "is corrupt.\n", journal->j_failed_commit,
1675 journal->j_devname);
1676 return -EFSCORRUPTED;
1677 }
1678
1679 /* OK, we've finished with the dynamic journal bits:
1680 * reinitialise the dynamic contents of the superblock in memory
1681 * and reset them on disk. */
1682 if (journal_reset(journal))
1683 goto recovery_error;
1684
1685 journal->j_flags &= ~JBD2_ABORT;
1686 journal->j_flags |= JBD2_LOADED;
1687 return 0;
1688
1689recovery_error:
1690 printk(KERN_WARNING "JBD2: recovery failed\n");
1691 return -EIO;
1692}
1693
1694/**
1695 * void jbd2_journal_destroy() - Release a journal_t structure.
1696 * @journal: Journal to act on.
1697 *
1698 * Release a journal_t structure once it is no longer in use by the
1699 * journaled object.
1700 * Return <0 if we couldn't clean up the journal.
1701 */
1702int jbd2_journal_destroy(journal_t *journal)
1703{
1704 int err = 0;
1705
1706 /* Wait for the commit thread to wake up and die. */
1707 journal_kill_thread(journal);
1708
1709 /* Force a final log commit */
1710 if (journal->j_running_transaction)
1711 jbd2_journal_commit_transaction(journal);
1712
1713 /* Force any old transactions to disk */
1714
1715 /* Totally anal locking here... */
1716 spin_lock(&journal->j_list_lock);
1717 while (journal->j_checkpoint_transactions != NULL) {
1718 spin_unlock(&journal->j_list_lock);
1719 mutex_lock(&journal->j_checkpoint_mutex);
1720 err = jbd2_log_do_checkpoint(journal);
1721 mutex_unlock(&journal->j_checkpoint_mutex);
1722 /*
1723 * If checkpointing failed, just free the buffers to avoid
1724 * looping forever
1725 */
1726 if (err) {
1727 jbd2_journal_destroy_checkpoint(journal);
1728 spin_lock(&journal->j_list_lock);
1729 break;
1730 }
1731 spin_lock(&journal->j_list_lock);
1732 }
1733
1734 J_ASSERT(journal->j_running_transaction == NULL);
1735 J_ASSERT(journal->j_committing_transaction == NULL);
1736 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1737 spin_unlock(&journal->j_list_lock);
1738
1739 if (journal->j_sb_buffer) {
1740 if (!is_journal_aborted(journal)) {
1741 mutex_lock(&journal->j_checkpoint_mutex);
1742
1743 write_lock(&journal->j_state_lock);
1744 journal->j_tail_sequence =
1745 ++journal->j_transaction_sequence;
1746 write_unlock(&journal->j_state_lock);
1747
1748 jbd2_mark_journal_empty(journal, WRITE_FLUSH_FUA);
1749 mutex_unlock(&journal->j_checkpoint_mutex);
1750 } else
1751 err = -EIO;
1752 brelse(journal->j_sb_buffer);
1753 }
1754
1755 if (journal->j_proc_entry)
1756 jbd2_stats_proc_exit(journal);
1757 iput(journal->j_inode);
1758 if (journal->j_revoke)
1759 jbd2_journal_destroy_revoke(journal);
1760 if (journal->j_chksum_driver)
1761 crypto_free_shash(journal->j_chksum_driver);
1762 kfree(journal->j_wbuf);
1763 kfree(journal);
1764
1765 return err;
1766}
1767
1768
1769/**
1770 *int jbd2_journal_check_used_features () - Check if features specified are used.
1771 * @journal: Journal to check.
1772 * @compat: bitmask of compatible features
1773 * @ro: bitmask of features that force read-only mount
1774 * @incompat: bitmask of incompatible features
1775 *
1776 * Check whether the journal uses all of a given set of
1777 * features. Return true (non-zero) if it does.
1778 **/
1779
1780int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1781 unsigned long ro, unsigned long incompat)
1782{
1783 journal_superblock_t *sb;
1784
1785 if (!compat && !ro && !incompat)
1786 return 1;
1787 /* Load journal superblock if it is not loaded yet. */
1788 if (journal->j_format_version == 0 &&
1789 journal_get_superblock(journal) != 0)
1790 return 0;
1791 if (journal->j_format_version == 1)
1792 return 0;
1793
1794 sb = journal->j_superblock;
1795
1796 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1797 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1798 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1799 return 1;
1800
1801 return 0;
1802}
1803
1804/**
1805 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1806 * @journal: Journal to check.
1807 * @compat: bitmask of compatible features
1808 * @ro: bitmask of features that force read-only mount
1809 * @incompat: bitmask of incompatible features
1810 *
1811 * Check whether the journaling code supports the use of
1812 * all of a given set of features on this journal. Return true
1813 * (non-zero) if it can. */
1814
1815int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1816 unsigned long ro, unsigned long incompat)
1817{
1818 if (!compat && !ro && !incompat)
1819 return 1;
1820
1821 /* We can support any known requested features iff the
1822 * superblock is in version 2. Otherwise we fail to support any
1823 * extended sb features. */
1824
1825 if (journal->j_format_version != 2)
1826 return 0;
1827
1828 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1829 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1830 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1831 return 1;
1832
1833 return 0;
1834}
1835
1836/**
1837 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1838 * @journal: Journal to act on.
1839 * @compat: bitmask of compatible features
1840 * @ro: bitmask of features that force read-only mount
1841 * @incompat: bitmask of incompatible features
1842 *
1843 * Mark a given journal feature as present on the
1844 * superblock. Returns true if the requested features could be set.
1845 *
1846 */
1847
1848int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1849 unsigned long ro, unsigned long incompat)
1850{
1851#define INCOMPAT_FEATURE_ON(f) \
1852 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
1853#define COMPAT_FEATURE_ON(f) \
1854 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
1855 journal_superblock_t *sb;
1856
1857 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1858 return 1;
1859
1860 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1861 return 0;
1862
1863 /* If enabling v2 checksums, turn on v3 instead */
1864 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
1865 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
1866 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
1867 }
1868
1869 /* Asking for checksumming v3 and v1? Only give them v3. */
1870 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
1871 compat & JBD2_FEATURE_COMPAT_CHECKSUM)
1872 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
1873
1874 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1875 compat, ro, incompat);
1876
1877 sb = journal->j_superblock;
1878
1879 /* If enabling v3 checksums, update superblock */
1880 if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
1881 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
1882 sb->s_feature_compat &=
1883 ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
1884
1885 /* Load the checksum driver */
1886 if (journal->j_chksum_driver == NULL) {
1887 journal->j_chksum_driver = crypto_alloc_shash("crc32c",
1888 0, 0);
1889 if (IS_ERR(journal->j_chksum_driver)) {
1890 printk(KERN_ERR "JBD2: Cannot load crc32c "
1891 "driver.\n");
1892 journal->j_chksum_driver = NULL;
1893 return 0;
1894 }
1895
1896 /* Precompute checksum seed for all metadata */
1897 journal->j_csum_seed = jbd2_chksum(journal, ~0,
1898 sb->s_uuid,
1899 sizeof(sb->s_uuid));
1900 }
1901 }
1902
1903 /* If enabling v1 checksums, downgrade superblock */
1904 if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
1905 sb->s_feature_incompat &=
1906 ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
1907 JBD2_FEATURE_INCOMPAT_CSUM_V3);
1908
1909 sb->s_feature_compat |= cpu_to_be32(compat);
1910 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1911 sb->s_feature_incompat |= cpu_to_be32(incompat);
1912
1913 return 1;
1914#undef COMPAT_FEATURE_ON
1915#undef INCOMPAT_FEATURE_ON
1916}
1917
1918/*
1919 * jbd2_journal_clear_features () - Clear a given journal feature in the
1920 * superblock
1921 * @journal: Journal to act on.
1922 * @compat: bitmask of compatible features
1923 * @ro: bitmask of features that force read-only mount
1924 * @incompat: bitmask of incompatible features
1925 *
1926 * Clear a given journal feature as present on the
1927 * superblock.
1928 */
1929void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1930 unsigned long ro, unsigned long incompat)
1931{
1932 journal_superblock_t *sb;
1933
1934 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1935 compat, ro, incompat);
1936
1937 sb = journal->j_superblock;
1938
1939 sb->s_feature_compat &= ~cpu_to_be32(compat);
1940 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1941 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
1942}
1943EXPORT_SYMBOL(jbd2_journal_clear_features);
1944
1945/**
1946 * int jbd2_journal_flush () - Flush journal
1947 * @journal: Journal to act on.
1948 *
1949 * Flush all data for a given journal to disk and empty the journal.
1950 * Filesystems can use this when remounting readonly to ensure that
1951 * recovery does not need to happen on remount.
1952 */
1953
1954int jbd2_journal_flush(journal_t *journal)
1955{
1956 int err = 0;
1957 transaction_t *transaction = NULL;
1958
1959 write_lock(&journal->j_state_lock);
1960
1961 /* Force everything buffered to the log... */
1962 if (journal->j_running_transaction) {
1963 transaction = journal->j_running_transaction;
1964 __jbd2_log_start_commit(journal, transaction->t_tid);
1965 } else if (journal->j_committing_transaction)
1966 transaction = journal->j_committing_transaction;
1967
1968 /* Wait for the log commit to complete... */
1969 if (transaction) {
1970 tid_t tid = transaction->t_tid;
1971
1972 write_unlock(&journal->j_state_lock);
1973 jbd2_log_wait_commit(journal, tid);
1974 } else {
1975 write_unlock(&journal->j_state_lock);
1976 }
1977
1978 /* ...and flush everything in the log out to disk. */
1979 spin_lock(&journal->j_list_lock);
1980 while (!err && journal->j_checkpoint_transactions != NULL) {
1981 spin_unlock(&journal->j_list_lock);
1982 mutex_lock(&journal->j_checkpoint_mutex);
1983 err = jbd2_log_do_checkpoint(journal);
1984 mutex_unlock(&journal->j_checkpoint_mutex);
1985 spin_lock(&journal->j_list_lock);
1986 }
1987 spin_unlock(&journal->j_list_lock);
1988
1989 if (is_journal_aborted(journal))
1990 return -EIO;
1991
1992 mutex_lock(&journal->j_checkpoint_mutex);
1993 if (!err) {
1994 err = jbd2_cleanup_journal_tail(journal);
1995 if (err < 0) {
1996 mutex_unlock(&journal->j_checkpoint_mutex);
1997 goto out;
1998 }
1999 err = 0;
2000 }
2001
2002 /* Finally, mark the journal as really needing no recovery.
2003 * This sets s_start==0 in the underlying superblock, which is
2004 * the magic code for a fully-recovered superblock. Any future
2005 * commits of data to the journal will restore the current
2006 * s_start value. */
2007 jbd2_mark_journal_empty(journal, WRITE_FUA);
2008 mutex_unlock(&journal->j_checkpoint_mutex);
2009 write_lock(&journal->j_state_lock);
2010 J_ASSERT(!journal->j_running_transaction);
2011 J_ASSERT(!journal->j_committing_transaction);
2012 J_ASSERT(!journal->j_checkpoint_transactions);
2013 J_ASSERT(journal->j_head == journal->j_tail);
2014 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2015 write_unlock(&journal->j_state_lock);
2016out:
2017 return err;
2018}
2019
2020/**
2021 * int jbd2_journal_wipe() - Wipe journal contents
2022 * @journal: Journal to act on.
2023 * @write: flag (see below)
2024 *
2025 * Wipe out all of the contents of a journal, safely. This will produce
2026 * a warning if the journal contains any valid recovery information.
2027 * Must be called between journal_init_*() and jbd2_journal_load().
2028 *
2029 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2030 * we merely suppress recovery.
2031 */
2032
2033int jbd2_journal_wipe(journal_t *journal, int write)
2034{
2035 int err = 0;
2036
2037 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2038
2039 err = load_superblock(journal);
2040 if (err)
2041 return err;
2042
2043 if (!journal->j_tail)
2044 goto no_recovery;
2045
2046 printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2047 write ? "Clearing" : "Ignoring");
2048
2049 err = jbd2_journal_skip_recovery(journal);
2050 if (write) {
2051 /* Lock to make assertions happy... */
2052 mutex_lock(&journal->j_checkpoint_mutex);
2053 jbd2_mark_journal_empty(journal, WRITE_FUA);
2054 mutex_unlock(&journal->j_checkpoint_mutex);
2055 }
2056
2057 no_recovery:
2058 return err;
2059}
2060
2061/*
2062 * Journal abort has very specific semantics, which we describe
2063 * for journal abort.
2064 *
2065 * Two internal functions, which provide abort to the jbd layer
2066 * itself are here.
2067 */
2068
2069/*
2070 * Quick version for internal journal use (doesn't lock the journal).
2071 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
2072 * and don't attempt to make any other journal updates.
2073 */
2074void __jbd2_journal_abort_hard(journal_t *journal)
2075{
2076 transaction_t *transaction;
2077
2078 if (journal->j_flags & JBD2_ABORT)
2079 return;
2080
2081 printk(KERN_ERR "Aborting journal on device %s.\n",
2082 journal->j_devname);
2083
2084 write_lock(&journal->j_state_lock);
2085 journal->j_flags |= JBD2_ABORT;
2086 transaction = journal->j_running_transaction;
2087 if (transaction)
2088 __jbd2_log_start_commit(journal, transaction->t_tid);
2089 write_unlock(&journal->j_state_lock);
2090}
2091
2092/* Soft abort: record the abort error status in the journal superblock,
2093 * but don't do any other IO. */
2094static void __journal_abort_soft (journal_t *journal, int errno)
2095{
2096 if (journal->j_flags & JBD2_ABORT)
2097 return;
2098
2099 if (!journal->j_errno)
2100 journal->j_errno = errno;
2101
2102 __jbd2_journal_abort_hard(journal);
2103
2104 if (errno) {
2105 jbd2_journal_update_sb_errno(journal);
2106 write_lock(&journal->j_state_lock);
2107 journal->j_flags |= JBD2_REC_ERR;
2108 write_unlock(&journal->j_state_lock);
2109 }
2110}
2111
2112/**
2113 * void jbd2_journal_abort () - Shutdown the journal immediately.
2114 * @journal: the journal to shutdown.
2115 * @errno: an error number to record in the journal indicating
2116 * the reason for the shutdown.
2117 *
2118 * Perform a complete, immediate shutdown of the ENTIRE
2119 * journal (not of a single transaction). This operation cannot be
2120 * undone without closing and reopening the journal.
2121 *
2122 * The jbd2_journal_abort function is intended to support higher level error
2123 * recovery mechanisms such as the ext2/ext3 remount-readonly error
2124 * mode.
2125 *
2126 * Journal abort has very specific semantics. Any existing dirty,
2127 * unjournaled buffers in the main filesystem will still be written to
2128 * disk by bdflush, but the journaling mechanism will be suspended
2129 * immediately and no further transaction commits will be honoured.
2130 *
2131 * Any dirty, journaled buffers will be written back to disk without
2132 * hitting the journal. Atomicity cannot be guaranteed on an aborted
2133 * filesystem, but we _do_ attempt to leave as much data as possible
2134 * behind for fsck to use for cleanup.
2135 *
2136 * Any attempt to get a new transaction handle on a journal which is in
2137 * ABORT state will just result in an -EROFS error return. A
2138 * jbd2_journal_stop on an existing handle will return -EIO if we have
2139 * entered abort state during the update.
2140 *
2141 * Recursive transactions are not disturbed by journal abort until the
2142 * final jbd2_journal_stop, which will receive the -EIO error.
2143 *
2144 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2145 * which will be recorded (if possible) in the journal superblock. This
2146 * allows a client to record failure conditions in the middle of a
2147 * transaction without having to complete the transaction to record the
2148 * failure to disk. ext3_error, for example, now uses this
2149 * functionality.
2150 *
2151 * Errors which originate from within the journaling layer will NOT
2152 * supply an errno; a null errno implies that absolutely no further
2153 * writes are done to the journal (unless there are any already in
2154 * progress).
2155 *
2156 */
2157
2158void jbd2_journal_abort(journal_t *journal, int errno)
2159{
2160 __journal_abort_soft(journal, errno);
2161}
2162
2163/**
2164 * int jbd2_journal_errno () - returns the journal's error state.
2165 * @journal: journal to examine.
2166 *
2167 * This is the errno number set with jbd2_journal_abort(), the last
2168 * time the journal was mounted - if the journal was stopped
2169 * without calling abort this will be 0.
2170 *
2171 * If the journal has been aborted on this mount time -EROFS will
2172 * be returned.
2173 */
2174int jbd2_journal_errno(journal_t *journal)
2175{
2176 int err;
2177
2178 read_lock(&journal->j_state_lock);
2179 if (journal->j_flags & JBD2_ABORT)
2180 err = -EROFS;
2181 else
2182 err = journal->j_errno;
2183 read_unlock(&journal->j_state_lock);
2184 return err;
2185}
2186
2187/**
2188 * int jbd2_journal_clear_err () - clears the journal's error state
2189 * @journal: journal to act on.
2190 *
2191 * An error must be cleared or acked to take a FS out of readonly
2192 * mode.
2193 */
2194int jbd2_journal_clear_err(journal_t *journal)
2195{
2196 int err = 0;
2197
2198 write_lock(&journal->j_state_lock);
2199 if (journal->j_flags & JBD2_ABORT)
2200 err = -EROFS;
2201 else
2202 journal->j_errno = 0;
2203 write_unlock(&journal->j_state_lock);
2204 return err;
2205}
2206
2207/**
2208 * void jbd2_journal_ack_err() - Ack journal err.
2209 * @journal: journal to act on.
2210 *
2211 * An error must be cleared or acked to take a FS out of readonly
2212 * mode.
2213 */
2214void jbd2_journal_ack_err(journal_t *journal)
2215{
2216 write_lock(&journal->j_state_lock);
2217 if (journal->j_errno)
2218 journal->j_flags |= JBD2_ACK_ERR;
2219 write_unlock(&journal->j_state_lock);
2220}
2221
2222int jbd2_journal_blocks_per_page(struct inode *inode)
2223{
2224 return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2225}
2226
2227/*
2228 * helper functions to deal with 32 or 64bit block numbers.
2229 */
2230size_t journal_tag_bytes(journal_t *journal)
2231{
2232 size_t sz;
2233
2234 if (jbd2_has_feature_csum3(journal))
2235 return sizeof(journal_block_tag3_t);
2236
2237 sz = sizeof(journal_block_tag_t);
2238
2239 if (jbd2_has_feature_csum2(journal))
2240 sz += sizeof(__u16);
2241
2242 if (jbd2_has_feature_64bit(journal))
2243 return sz;
2244 else
2245 return sz - sizeof(__u32);
2246}
2247
2248/*
2249 * JBD memory management
2250 *
2251 * These functions are used to allocate block-sized chunks of memory
2252 * used for making copies of buffer_head data. Very often it will be
2253 * page-sized chunks of data, but sometimes it will be in
2254 * sub-page-size chunks. (For example, 16k pages on Power systems
2255 * with a 4k block file system.) For blocks smaller than a page, we
2256 * use a SLAB allocator. There are slab caches for each block size,
2257 * which are allocated at mount time, if necessary, and we only free
2258 * (all of) the slab caches when/if the jbd2 module is unloaded. For
2259 * this reason we don't need to a mutex to protect access to
2260 * jbd2_slab[] allocating or releasing memory; only in
2261 * jbd2_journal_create_slab().
2262 */
2263#define JBD2_MAX_SLABS 8
2264static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2265
2266static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2267 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2268 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2269};
2270
2271
2272static void jbd2_journal_destroy_slabs(void)
2273{
2274 int i;
2275
2276 for (i = 0; i < JBD2_MAX_SLABS; i++) {
2277 if (jbd2_slab[i])
2278 kmem_cache_destroy(jbd2_slab[i]);
2279 jbd2_slab[i] = NULL;
2280 }
2281}
2282
2283static int jbd2_journal_create_slab(size_t size)
2284{
2285 static DEFINE_MUTEX(jbd2_slab_create_mutex);
2286 int i = order_base_2(size) - 10;
2287 size_t slab_size;
2288
2289 if (size == PAGE_SIZE)
2290 return 0;
2291
2292 if (i >= JBD2_MAX_SLABS)
2293 return -EINVAL;
2294
2295 if (unlikely(i < 0))
2296 i = 0;
2297 mutex_lock(&jbd2_slab_create_mutex);
2298 if (jbd2_slab[i]) {
2299 mutex_unlock(&jbd2_slab_create_mutex);
2300 return 0; /* Already created */
2301 }
2302
2303 slab_size = 1 << (i+10);
2304 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2305 slab_size, 0, NULL);
2306 mutex_unlock(&jbd2_slab_create_mutex);
2307 if (!jbd2_slab[i]) {
2308 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2309 return -ENOMEM;
2310 }
2311 return 0;
2312}
2313
2314static struct kmem_cache *get_slab(size_t size)
2315{
2316 int i = order_base_2(size) - 10;
2317
2318 BUG_ON(i >= JBD2_MAX_SLABS);
2319 if (unlikely(i < 0))
2320 i = 0;
2321 BUG_ON(jbd2_slab[i] == NULL);
2322 return jbd2_slab[i];
2323}
2324
2325void *jbd2_alloc(size_t size, gfp_t flags)
2326{
2327 void *ptr;
2328
2329 BUG_ON(size & (size-1)); /* Must be a power of 2 */
2330
2331 flags |= __GFP_REPEAT;
2332 if (size == PAGE_SIZE)
2333 ptr = (void *)__get_free_pages(flags, 0);
2334 else if (size > PAGE_SIZE) {
2335 int order = get_order(size);
2336
2337 if (order < 3)
2338 ptr = (void *)__get_free_pages(flags, order);
2339 else
2340 ptr = vmalloc(size);
2341 } else
2342 ptr = kmem_cache_alloc(get_slab(size), flags);
2343
2344 /* Check alignment; SLUB has gotten this wrong in the past,
2345 * and this can lead to user data corruption! */
2346 BUG_ON(((unsigned long) ptr) & (size-1));
2347
2348 return ptr;
2349}
2350
2351void jbd2_free(void *ptr, size_t size)
2352{
2353 if (size == PAGE_SIZE) {
2354 free_pages((unsigned long)ptr, 0);
2355 return;
2356 }
2357 if (size > PAGE_SIZE) {
2358 int order = get_order(size);
2359
2360 if (order < 3)
2361 free_pages((unsigned long)ptr, order);
2362 else
2363 vfree(ptr);
2364 return;
2365 }
2366 kmem_cache_free(get_slab(size), ptr);
2367};
2368
2369/*
2370 * Journal_head storage management
2371 */
2372static struct kmem_cache *jbd2_journal_head_cache;
2373#ifdef CONFIG_JBD2_DEBUG
2374static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2375#endif
2376
2377static int jbd2_journal_init_journal_head_cache(void)
2378{
2379 int retval;
2380
2381 J_ASSERT(jbd2_journal_head_cache == NULL);
2382 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2383 sizeof(struct journal_head),
2384 0, /* offset */
2385 SLAB_TEMPORARY | SLAB_DESTROY_BY_RCU,
2386 NULL); /* ctor */
2387 retval = 0;
2388 if (!jbd2_journal_head_cache) {
2389 retval = -ENOMEM;
2390 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2391 }
2392 return retval;
2393}
2394
2395static void jbd2_journal_destroy_journal_head_cache(void)
2396{
2397 if (jbd2_journal_head_cache) {
2398 kmem_cache_destroy(jbd2_journal_head_cache);
2399 jbd2_journal_head_cache = NULL;
2400 }
2401}
2402
2403/*
2404 * journal_head splicing and dicing
2405 */
2406static struct journal_head *journal_alloc_journal_head(void)
2407{
2408 struct journal_head *ret;
2409
2410#ifdef CONFIG_JBD2_DEBUG
2411 atomic_inc(&nr_journal_heads);
2412#endif
2413 ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2414 if (!ret) {
2415 jbd_debug(1, "out of memory for journal_head\n");
2416 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2417 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2418 GFP_NOFS | __GFP_NOFAIL);
2419 }
2420 return ret;
2421}
2422
2423static void journal_free_journal_head(struct journal_head *jh)
2424{
2425#ifdef CONFIG_JBD2_DEBUG
2426 atomic_dec(&nr_journal_heads);
2427 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2428#endif
2429 kmem_cache_free(jbd2_journal_head_cache, jh);
2430}
2431
2432/*
2433 * A journal_head is attached to a buffer_head whenever JBD has an
2434 * interest in the buffer.
2435 *
2436 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2437 * is set. This bit is tested in core kernel code where we need to take
2438 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2439 * there.
2440 *
2441 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2442 *
2443 * When a buffer has its BH_JBD bit set it is immune from being released by
2444 * core kernel code, mainly via ->b_count.
2445 *
2446 * A journal_head is detached from its buffer_head when the journal_head's
2447 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2448 * transaction (b_cp_transaction) hold their references to b_jcount.
2449 *
2450 * Various places in the kernel want to attach a journal_head to a buffer_head
2451 * _before_ attaching the journal_head to a transaction. To protect the
2452 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2453 * journal_head's b_jcount refcount by one. The caller must call
2454 * jbd2_journal_put_journal_head() to undo this.
2455 *
2456 * So the typical usage would be:
2457 *
2458 * (Attach a journal_head if needed. Increments b_jcount)
2459 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2460 * ...
2461 * (Get another reference for transaction)
2462 * jbd2_journal_grab_journal_head(bh);
2463 * jh->b_transaction = xxx;
2464 * (Put original reference)
2465 * jbd2_journal_put_journal_head(jh);
2466 */
2467
2468/*
2469 * Give a buffer_head a journal_head.
2470 *
2471 * May sleep.
2472 */
2473struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2474{
2475 struct journal_head *jh;
2476 struct journal_head *new_jh = NULL;
2477
2478repeat:
2479 if (!buffer_jbd(bh))
2480 new_jh = journal_alloc_journal_head();
2481
2482 jbd_lock_bh_journal_head(bh);
2483 if (buffer_jbd(bh)) {
2484 jh = bh2jh(bh);
2485 } else {
2486 J_ASSERT_BH(bh,
2487 (atomic_read(&bh->b_count) > 0) ||
2488 (bh->b_page && bh->b_page->mapping));
2489
2490 if (!new_jh) {
2491 jbd_unlock_bh_journal_head(bh);
2492 goto repeat;
2493 }
2494
2495 jh = new_jh;
2496 new_jh = NULL; /* We consumed it */
2497 set_buffer_jbd(bh);
2498 bh->b_private = jh;
2499 jh->b_bh = bh;
2500 get_bh(bh);
2501 BUFFER_TRACE(bh, "added journal_head");
2502 }
2503 jh->b_jcount++;
2504 jbd_unlock_bh_journal_head(bh);
2505 if (new_jh)
2506 journal_free_journal_head(new_jh);
2507 return bh->b_private;
2508}
2509
2510/*
2511 * Grab a ref against this buffer_head's journal_head. If it ended up not
2512 * having a journal_head, return NULL
2513 */
2514struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2515{
2516 struct journal_head *jh = NULL;
2517
2518 jbd_lock_bh_journal_head(bh);
2519 if (buffer_jbd(bh)) {
2520 jh = bh2jh(bh);
2521 jh->b_jcount++;
2522 }
2523 jbd_unlock_bh_journal_head(bh);
2524 return jh;
2525}
2526
2527static void __journal_remove_journal_head(struct buffer_head *bh)
2528{
2529 struct journal_head *jh = bh2jh(bh);
2530
2531 J_ASSERT_JH(jh, jh->b_jcount >= 0);
2532 J_ASSERT_JH(jh, jh->b_transaction == NULL);
2533 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2534 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2535 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2536 J_ASSERT_BH(bh, buffer_jbd(bh));
2537 J_ASSERT_BH(bh, jh2bh(jh) == bh);
2538 BUFFER_TRACE(bh, "remove journal_head");
2539 if (jh->b_frozen_data) {
2540 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2541 jbd2_free(jh->b_frozen_data, bh->b_size);
2542 }
2543 if (jh->b_committed_data) {
2544 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2545 jbd2_free(jh->b_committed_data, bh->b_size);
2546 }
2547 bh->b_private = NULL;
2548 jh->b_bh = NULL; /* debug, really */
2549 clear_buffer_jbd(bh);
2550 journal_free_journal_head(jh);
2551}
2552
2553/*
2554 * Drop a reference on the passed journal_head. If it fell to zero then
2555 * release the journal_head from the buffer_head.
2556 */
2557void jbd2_journal_put_journal_head(struct journal_head *jh)
2558{
2559 struct buffer_head *bh = jh2bh(jh);
2560
2561 jbd_lock_bh_journal_head(bh);
2562 J_ASSERT_JH(jh, jh->b_jcount > 0);
2563 --jh->b_jcount;
2564 if (!jh->b_jcount) {
2565 __journal_remove_journal_head(bh);
2566 jbd_unlock_bh_journal_head(bh);
2567 __brelse(bh);
2568 } else
2569 jbd_unlock_bh_journal_head(bh);
2570}
2571
2572/*
2573 * Initialize jbd inode head
2574 */
2575void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2576{
2577 jinode->i_transaction = NULL;
2578 jinode->i_next_transaction = NULL;
2579 jinode->i_vfs_inode = inode;
2580 jinode->i_flags = 0;
2581 INIT_LIST_HEAD(&jinode->i_list);
2582}
2583
2584/*
2585 * Function to be called before we start removing inode from memory (i.e.,
2586 * clear_inode() is a fine place to be called from). It removes inode from
2587 * transaction's lists.
2588 */
2589void jbd2_journal_release_jbd_inode(journal_t *journal,
2590 struct jbd2_inode *jinode)
2591{
2592 if (!journal)
2593 return;
2594restart:
2595 spin_lock(&journal->j_list_lock);
2596 /* Is commit writing out inode - we have to wait */
2597 if (jinode->i_flags & JI_COMMIT_RUNNING) {
2598 wait_queue_head_t *wq;
2599 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2600 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2601 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2602 spin_unlock(&journal->j_list_lock);
2603 schedule();
2604 finish_wait(wq, &wait.wait);
2605 goto restart;
2606 }
2607
2608 if (jinode->i_transaction) {
2609 list_del(&jinode->i_list);
2610 jinode->i_transaction = NULL;
2611 }
2612 spin_unlock(&journal->j_list_lock);
2613}
2614
2615
2616#ifdef CONFIG_PROC_FS
2617
2618#define JBD2_STATS_PROC_NAME "fs/jbd2"
2619
2620static void __init jbd2_create_jbd_stats_proc_entry(void)
2621{
2622 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2623}
2624
2625static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2626{
2627 if (proc_jbd2_stats)
2628 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2629}
2630
2631#else
2632
2633#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2634#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2635
2636#endif
2637
2638struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
2639
2640static int __init jbd2_journal_init_handle_cache(void)
2641{
2642 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
2643 if (jbd2_handle_cache == NULL) {
2644 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
2645 return -ENOMEM;
2646 }
2647 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
2648 if (jbd2_inode_cache == NULL) {
2649 printk(KERN_EMERG "JBD2: failed to create inode cache\n");
2650 kmem_cache_destroy(jbd2_handle_cache);
2651 return -ENOMEM;
2652 }
2653 return 0;
2654}
2655
2656static void jbd2_journal_destroy_handle_cache(void)
2657{
2658 if (jbd2_handle_cache)
2659 kmem_cache_destroy(jbd2_handle_cache);
2660 if (jbd2_inode_cache)
2661 kmem_cache_destroy(jbd2_inode_cache);
2662
2663}
2664
2665/*
2666 * Module startup and shutdown
2667 */
2668
2669static int __init journal_init_caches(void)
2670{
2671 int ret;
2672
2673 ret = jbd2_journal_init_revoke_caches();
2674 if (ret == 0)
2675 ret = jbd2_journal_init_journal_head_cache();
2676 if (ret == 0)
2677 ret = jbd2_journal_init_handle_cache();
2678 if (ret == 0)
2679 ret = jbd2_journal_init_transaction_cache();
2680 return ret;
2681}
2682
2683static void jbd2_journal_destroy_caches(void)
2684{
2685 jbd2_journal_destroy_revoke_caches();
2686 jbd2_journal_destroy_journal_head_cache();
2687 jbd2_journal_destroy_handle_cache();
2688 jbd2_journal_destroy_transaction_cache();
2689 jbd2_journal_destroy_slabs();
2690}
2691
2692static int __init journal_init(void)
2693{
2694 int ret;
2695
2696 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2697
2698 ret = journal_init_caches();
2699 if (ret == 0) {
2700 jbd2_create_jbd_stats_proc_entry();
2701 } else {
2702 jbd2_journal_destroy_caches();
2703 }
2704 return ret;
2705}
2706
2707static void __exit journal_exit(void)
2708{
2709#ifdef CONFIG_JBD2_DEBUG
2710 int n = atomic_read(&nr_journal_heads);
2711 if (n)
2712 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
2713#endif
2714 jbd2_remove_jbd_stats_proc_entry();
2715 jbd2_journal_destroy_caches();
2716}
2717
2718MODULE_LICENSE("GPL");
2719module_init(journal_init);
2720module_exit(journal_exit);
2721
1/*
2 * linux/fs/jbd2/journal.c
3 *
4 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
5 *
6 * Copyright 1998 Red Hat corp --- All Rights Reserved
7 *
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.
11 *
12 * Generic filesystem journal-writing code; part of the ext2fs
13 * journaling system.
14 *
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.
18 *
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).
23 */
24
25#include <linux/module.h>
26#include <linux/time.h>
27#include <linux/fs.h>
28#include <linux/jbd2.h>
29#include <linux/errno.h>
30#include <linux/slab.h>
31#include <linux/init.h>
32#include <linux/mm.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/seq_file.h>
39#include <linux/math64.h>
40#include <linux/hash.h>
41#include <linux/log2.h>
42#include <linux/vmalloc.h>
43#include <linux/backing-dev.h>
44#include <linux/bitops.h>
45#include <linux/ratelimit.h>
46
47#define CREATE_TRACE_POINTS
48#include <trace/events/jbd2.h>
49
50#include <linux/uaccess.h>
51#include <asm/page.h>
52
53#ifdef CONFIG_JBD2_DEBUG
54ushort jbd2_journal_enable_debug __read_mostly;
55EXPORT_SYMBOL(jbd2_journal_enable_debug);
56
57module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
58MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
59#endif
60
61EXPORT_SYMBOL(jbd2_journal_extend);
62EXPORT_SYMBOL(jbd2_journal_stop);
63EXPORT_SYMBOL(jbd2_journal_lock_updates);
64EXPORT_SYMBOL(jbd2_journal_unlock_updates);
65EXPORT_SYMBOL(jbd2_journal_get_write_access);
66EXPORT_SYMBOL(jbd2_journal_get_create_access);
67EXPORT_SYMBOL(jbd2_journal_get_undo_access);
68EXPORT_SYMBOL(jbd2_journal_set_triggers);
69EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
70EXPORT_SYMBOL(jbd2_journal_forget);
71#if 0
72EXPORT_SYMBOL(journal_sync_buffer);
73#endif
74EXPORT_SYMBOL(jbd2_journal_flush);
75EXPORT_SYMBOL(jbd2_journal_revoke);
76
77EXPORT_SYMBOL(jbd2_journal_init_dev);
78EXPORT_SYMBOL(jbd2_journal_init_inode);
79EXPORT_SYMBOL(jbd2_journal_check_used_features);
80EXPORT_SYMBOL(jbd2_journal_check_available_features);
81EXPORT_SYMBOL(jbd2_journal_set_features);
82EXPORT_SYMBOL(jbd2_journal_load);
83EXPORT_SYMBOL(jbd2_journal_destroy);
84EXPORT_SYMBOL(jbd2_journal_abort);
85EXPORT_SYMBOL(jbd2_journal_errno);
86EXPORT_SYMBOL(jbd2_journal_ack_err);
87EXPORT_SYMBOL(jbd2_journal_clear_err);
88EXPORT_SYMBOL(jbd2_log_wait_commit);
89EXPORT_SYMBOL(jbd2_log_start_commit);
90EXPORT_SYMBOL(jbd2_journal_start_commit);
91EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
92EXPORT_SYMBOL(jbd2_journal_wipe);
93EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
94EXPORT_SYMBOL(jbd2_journal_invalidatepage);
95EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
96EXPORT_SYMBOL(jbd2_journal_force_commit);
97EXPORT_SYMBOL(jbd2_journal_inode_add_write);
98EXPORT_SYMBOL(jbd2_journal_inode_add_wait);
99EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
100EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
101EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
102EXPORT_SYMBOL(jbd2_inode_cache);
103
104static void __journal_abort_soft (journal_t *journal, int errno);
105static int jbd2_journal_create_slab(size_t slab_size);
106
107#ifdef CONFIG_JBD2_DEBUG
108void __jbd2_debug(int level, const char *file, const char *func,
109 unsigned int line, const char *fmt, ...)
110{
111 struct va_format vaf;
112 va_list args;
113
114 if (level > jbd2_journal_enable_debug)
115 return;
116 va_start(args, fmt);
117 vaf.fmt = fmt;
118 vaf.va = &args;
119 printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf);
120 va_end(args);
121}
122EXPORT_SYMBOL(__jbd2_debug);
123#endif
124
125/* Checksumming functions */
126static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
127{
128 if (!jbd2_journal_has_csum_v2or3_feature(j))
129 return 1;
130
131 return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
132}
133
134static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
135{
136 __u32 csum;
137 __be32 old_csum;
138
139 old_csum = sb->s_checksum;
140 sb->s_checksum = 0;
141 csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
142 sb->s_checksum = old_csum;
143
144 return cpu_to_be32(csum);
145}
146
147static int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
148{
149 if (!jbd2_journal_has_csum_v2or3(j))
150 return 1;
151
152 return sb->s_checksum == jbd2_superblock_csum(j, sb);
153}
154
155static void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
156{
157 if (!jbd2_journal_has_csum_v2or3(j))
158 return;
159
160 sb->s_checksum = jbd2_superblock_csum(j, sb);
161}
162
163/*
164 * Helper function used to manage commit timeouts
165 */
166
167static void commit_timeout(unsigned long __data)
168{
169 struct task_struct * p = (struct task_struct *) __data;
170
171 wake_up_process(p);
172}
173
174/*
175 * kjournald2: The main thread function used to manage a logging device
176 * journal.
177 *
178 * This kernel thread is responsible for two things:
179 *
180 * 1) COMMIT: Every so often we need to commit the current state of the
181 * filesystem to disk. The journal thread is responsible for writing
182 * all of the metadata buffers to disk.
183 *
184 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
185 * of the data in that part of the log has been rewritten elsewhere on
186 * the disk. Flushing these old buffers to reclaim space in the log is
187 * known as checkpointing, and this thread is responsible for that job.
188 */
189
190static int kjournald2(void *arg)
191{
192 journal_t *journal = arg;
193 transaction_t *transaction;
194
195 /*
196 * Set up an interval timer which can be used to trigger a commit wakeup
197 * after the commit interval expires
198 */
199 setup_timer(&journal->j_commit_timer, commit_timeout,
200 (unsigned long)current);
201
202 set_freezable();
203
204 /* Record that the journal thread is running */
205 journal->j_task = current;
206 wake_up(&journal->j_wait_done_commit);
207
208 /*
209 * And now, wait forever for commit wakeup events.
210 */
211 write_lock(&journal->j_state_lock);
212
213loop:
214 if (journal->j_flags & JBD2_UNMOUNT)
215 goto end_loop;
216
217 jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
218 journal->j_commit_sequence, journal->j_commit_request);
219
220 if (journal->j_commit_sequence != journal->j_commit_request) {
221 jbd_debug(1, "OK, requests differ\n");
222 write_unlock(&journal->j_state_lock);
223 del_timer_sync(&journal->j_commit_timer);
224 jbd2_journal_commit_transaction(journal);
225 write_lock(&journal->j_state_lock);
226 goto loop;
227 }
228
229 wake_up(&journal->j_wait_done_commit);
230 if (freezing(current)) {
231 /*
232 * The simpler the better. Flushing journal isn't a
233 * good idea, because that depends on threads that may
234 * be already stopped.
235 */
236 jbd_debug(1, "Now suspending kjournald2\n");
237 write_unlock(&journal->j_state_lock);
238 try_to_freeze();
239 write_lock(&journal->j_state_lock);
240 } else {
241 /*
242 * We assume on resume that commits are already there,
243 * so we don't sleep
244 */
245 DEFINE_WAIT(wait);
246 int should_sleep = 1;
247
248 prepare_to_wait(&journal->j_wait_commit, &wait,
249 TASK_INTERRUPTIBLE);
250 if (journal->j_commit_sequence != journal->j_commit_request)
251 should_sleep = 0;
252 transaction = journal->j_running_transaction;
253 if (transaction && time_after_eq(jiffies,
254 transaction->t_expires))
255 should_sleep = 0;
256 if (journal->j_flags & JBD2_UNMOUNT)
257 should_sleep = 0;
258 if (should_sleep) {
259 write_unlock(&journal->j_state_lock);
260 schedule();
261 write_lock(&journal->j_state_lock);
262 }
263 finish_wait(&journal->j_wait_commit, &wait);
264 }
265
266 jbd_debug(1, "kjournald2 wakes\n");
267
268 /*
269 * Were we woken up by a commit wakeup event?
270 */
271 transaction = journal->j_running_transaction;
272 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
273 journal->j_commit_request = transaction->t_tid;
274 jbd_debug(1, "woke because of timeout\n");
275 }
276 goto loop;
277
278end_loop:
279 write_unlock(&journal->j_state_lock);
280 del_timer_sync(&journal->j_commit_timer);
281 journal->j_task = NULL;
282 wake_up(&journal->j_wait_done_commit);
283 jbd_debug(1, "Journal thread exiting.\n");
284 return 0;
285}
286
287static int jbd2_journal_start_thread(journal_t *journal)
288{
289 struct task_struct *t;
290
291 t = kthread_run(kjournald2, journal, "jbd2/%s",
292 journal->j_devname);
293 if (IS_ERR(t))
294 return PTR_ERR(t);
295
296 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
297 return 0;
298}
299
300static void journal_kill_thread(journal_t *journal)
301{
302 write_lock(&journal->j_state_lock);
303 journal->j_flags |= JBD2_UNMOUNT;
304
305 while (journal->j_task) {
306 write_unlock(&journal->j_state_lock);
307 wake_up(&journal->j_wait_commit);
308 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
309 write_lock(&journal->j_state_lock);
310 }
311 write_unlock(&journal->j_state_lock);
312}
313
314/*
315 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
316 *
317 * Writes a metadata buffer to a given disk block. The actual IO is not
318 * performed but a new buffer_head is constructed which labels the data
319 * to be written with the correct destination disk block.
320 *
321 * Any magic-number escaping which needs to be done will cause a
322 * copy-out here. If the buffer happens to start with the
323 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
324 * magic number is only written to the log for descripter blocks. In
325 * this case, we copy the data and replace the first word with 0, and we
326 * return a result code which indicates that this buffer needs to be
327 * marked as an escaped buffer in the corresponding log descriptor
328 * block. The missing word can then be restored when the block is read
329 * during recovery.
330 *
331 * If the source buffer has already been modified by a new transaction
332 * since we took the last commit snapshot, we use the frozen copy of
333 * that data for IO. If we end up using the existing buffer_head's data
334 * for the write, then we have to make sure nobody modifies it while the
335 * IO is in progress. do_get_write_access() handles this.
336 *
337 * The function returns a pointer to the buffer_head to be used for IO.
338 *
339 *
340 * Return value:
341 * <0: Error
342 * >=0: Finished OK
343 *
344 * On success:
345 * Bit 0 set == escape performed on the data
346 * Bit 1 set == buffer copy-out performed (kfree the data after IO)
347 */
348
349int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
350 struct journal_head *jh_in,
351 struct buffer_head **bh_out,
352 sector_t blocknr)
353{
354 int need_copy_out = 0;
355 int done_copy_out = 0;
356 int do_escape = 0;
357 char *mapped_data;
358 struct buffer_head *new_bh;
359 struct page *new_page;
360 unsigned int new_offset;
361 struct buffer_head *bh_in = jh2bh(jh_in);
362 journal_t *journal = transaction->t_journal;
363
364 /*
365 * The buffer really shouldn't be locked: only the current committing
366 * transaction is allowed to write it, so nobody else is allowed
367 * to do any IO.
368 *
369 * akpm: except if we're journalling data, and write() output is
370 * also part of a shared mapping, and another thread has
371 * decided to launch a writepage() against this buffer.
372 */
373 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
374
375 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
376
377 /* keep subsequent assertions sane */
378 atomic_set(&new_bh->b_count, 1);
379
380 jbd_lock_bh_state(bh_in);
381repeat:
382 /*
383 * If a new transaction has already done a buffer copy-out, then
384 * we use that version of the data for the commit.
385 */
386 if (jh_in->b_frozen_data) {
387 done_copy_out = 1;
388 new_page = virt_to_page(jh_in->b_frozen_data);
389 new_offset = offset_in_page(jh_in->b_frozen_data);
390 } else {
391 new_page = jh2bh(jh_in)->b_page;
392 new_offset = offset_in_page(jh2bh(jh_in)->b_data);
393 }
394
395 mapped_data = kmap_atomic(new_page);
396 /*
397 * Fire data frozen trigger if data already wasn't frozen. Do this
398 * before checking for escaping, as the trigger may modify the magic
399 * offset. If a copy-out happens afterwards, it will have the correct
400 * data in the buffer.
401 */
402 if (!done_copy_out)
403 jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
404 jh_in->b_triggers);
405
406 /*
407 * Check for escaping
408 */
409 if (*((__be32 *)(mapped_data + new_offset)) ==
410 cpu_to_be32(JBD2_MAGIC_NUMBER)) {
411 need_copy_out = 1;
412 do_escape = 1;
413 }
414 kunmap_atomic(mapped_data);
415
416 /*
417 * Do we need to do a data copy?
418 */
419 if (need_copy_out && !done_copy_out) {
420 char *tmp;
421
422 jbd_unlock_bh_state(bh_in);
423 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
424 if (!tmp) {
425 brelse(new_bh);
426 return -ENOMEM;
427 }
428 jbd_lock_bh_state(bh_in);
429 if (jh_in->b_frozen_data) {
430 jbd2_free(tmp, bh_in->b_size);
431 goto repeat;
432 }
433
434 jh_in->b_frozen_data = tmp;
435 mapped_data = kmap_atomic(new_page);
436 memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
437 kunmap_atomic(mapped_data);
438
439 new_page = virt_to_page(tmp);
440 new_offset = offset_in_page(tmp);
441 done_copy_out = 1;
442
443 /*
444 * This isn't strictly necessary, as we're using frozen
445 * data for the escaping, but it keeps consistency with
446 * b_frozen_data usage.
447 */
448 jh_in->b_frozen_triggers = jh_in->b_triggers;
449 }
450
451 /*
452 * Did we need to do an escaping? Now we've done all the
453 * copying, we can finally do so.
454 */
455 if (do_escape) {
456 mapped_data = kmap_atomic(new_page);
457 *((unsigned int *)(mapped_data + new_offset)) = 0;
458 kunmap_atomic(mapped_data);
459 }
460
461 set_bh_page(new_bh, new_page, new_offset);
462 new_bh->b_size = bh_in->b_size;
463 new_bh->b_bdev = journal->j_dev;
464 new_bh->b_blocknr = blocknr;
465 new_bh->b_private = bh_in;
466 set_buffer_mapped(new_bh);
467 set_buffer_dirty(new_bh);
468
469 *bh_out = new_bh;
470
471 /*
472 * The to-be-written buffer needs to get moved to the io queue,
473 * and the original buffer whose contents we are shadowing or
474 * copying is moved to the transaction's shadow queue.
475 */
476 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
477 spin_lock(&journal->j_list_lock);
478 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
479 spin_unlock(&journal->j_list_lock);
480 set_buffer_shadow(bh_in);
481 jbd_unlock_bh_state(bh_in);
482
483 return do_escape | (done_copy_out << 1);
484}
485
486/*
487 * Allocation code for the journal file. Manage the space left in the
488 * journal, so that we can begin checkpointing when appropriate.
489 */
490
491/*
492 * Called with j_state_lock locked for writing.
493 * Returns true if a transaction commit was started.
494 */
495int __jbd2_log_start_commit(journal_t *journal, tid_t target)
496{
497 /* Return if the txn has already requested to be committed */
498 if (journal->j_commit_request == target)
499 return 0;
500
501 /*
502 * The only transaction we can possibly wait upon is the
503 * currently running transaction (if it exists). Otherwise,
504 * the target tid must be an old one.
505 */
506 if (journal->j_running_transaction &&
507 journal->j_running_transaction->t_tid == target) {
508 /*
509 * We want a new commit: OK, mark the request and wakeup the
510 * commit thread. We do _not_ do the commit ourselves.
511 */
512
513 journal->j_commit_request = target;
514 jbd_debug(1, "JBD2: requesting commit %d/%d\n",
515 journal->j_commit_request,
516 journal->j_commit_sequence);
517 journal->j_running_transaction->t_requested = jiffies;
518 wake_up(&journal->j_wait_commit);
519 return 1;
520 } else if (!tid_geq(journal->j_commit_request, target))
521 /* This should never happen, but if it does, preserve
522 the evidence before kjournald goes into a loop and
523 increments j_commit_sequence beyond all recognition. */
524 WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
525 journal->j_commit_request,
526 journal->j_commit_sequence,
527 target, journal->j_running_transaction ?
528 journal->j_running_transaction->t_tid : 0);
529 return 0;
530}
531
532int jbd2_log_start_commit(journal_t *journal, tid_t tid)
533{
534 int ret;
535
536 write_lock(&journal->j_state_lock);
537 ret = __jbd2_log_start_commit(journal, tid);
538 write_unlock(&journal->j_state_lock);
539 return ret;
540}
541
542/*
543 * Force and wait any uncommitted transactions. We can only force the running
544 * transaction if we don't have an active handle, otherwise, we will deadlock.
545 * Returns: <0 in case of error,
546 * 0 if nothing to commit,
547 * 1 if transaction was successfully committed.
548 */
549static int __jbd2_journal_force_commit(journal_t *journal)
550{
551 transaction_t *transaction = NULL;
552 tid_t tid;
553 int need_to_start = 0, ret = 0;
554
555 read_lock(&journal->j_state_lock);
556 if (journal->j_running_transaction && !current->journal_info) {
557 transaction = journal->j_running_transaction;
558 if (!tid_geq(journal->j_commit_request, transaction->t_tid))
559 need_to_start = 1;
560 } else if (journal->j_committing_transaction)
561 transaction = journal->j_committing_transaction;
562
563 if (!transaction) {
564 /* Nothing to commit */
565 read_unlock(&journal->j_state_lock);
566 return 0;
567 }
568 tid = transaction->t_tid;
569 read_unlock(&journal->j_state_lock);
570 if (need_to_start)
571 jbd2_log_start_commit(journal, tid);
572 ret = jbd2_log_wait_commit(journal, tid);
573 if (!ret)
574 ret = 1;
575
576 return ret;
577}
578
579/**
580 * Force and wait upon a commit if the calling process is not within
581 * transaction. This is used for forcing out undo-protected data which contains
582 * bitmaps, when the fs is running out of space.
583 *
584 * @journal: journal to force
585 * Returns true if progress was made.
586 */
587int jbd2_journal_force_commit_nested(journal_t *journal)
588{
589 int ret;
590
591 ret = __jbd2_journal_force_commit(journal);
592 return ret > 0;
593}
594
595/**
596 * int journal_force_commit() - force any uncommitted transactions
597 * @journal: journal to force
598 *
599 * Caller want unconditional commit. We can only force the running transaction
600 * if we don't have an active handle, otherwise, we will deadlock.
601 */
602int jbd2_journal_force_commit(journal_t *journal)
603{
604 int ret;
605
606 J_ASSERT(!current->journal_info);
607 ret = __jbd2_journal_force_commit(journal);
608 if (ret > 0)
609 ret = 0;
610 return ret;
611}
612
613/*
614 * Start a commit of the current running transaction (if any). Returns true
615 * if a transaction is going to be committed (or is currently already
616 * committing), and fills its tid in at *ptid
617 */
618int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
619{
620 int ret = 0;
621
622 write_lock(&journal->j_state_lock);
623 if (journal->j_running_transaction) {
624 tid_t tid = journal->j_running_transaction->t_tid;
625
626 __jbd2_log_start_commit(journal, tid);
627 /* There's a running transaction and we've just made sure
628 * it's commit has been scheduled. */
629 if (ptid)
630 *ptid = tid;
631 ret = 1;
632 } else if (journal->j_committing_transaction) {
633 /*
634 * If commit has been started, then we have to wait for
635 * completion of that transaction.
636 */
637 if (ptid)
638 *ptid = journal->j_committing_transaction->t_tid;
639 ret = 1;
640 }
641 write_unlock(&journal->j_state_lock);
642 return ret;
643}
644
645/*
646 * Return 1 if a given transaction has not yet sent barrier request
647 * connected with a transaction commit. If 0 is returned, transaction
648 * may or may not have sent the barrier. Used to avoid sending barrier
649 * twice in common cases.
650 */
651int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
652{
653 int ret = 0;
654 transaction_t *commit_trans;
655
656 if (!(journal->j_flags & JBD2_BARRIER))
657 return 0;
658 read_lock(&journal->j_state_lock);
659 /* Transaction already committed? */
660 if (tid_geq(journal->j_commit_sequence, tid))
661 goto out;
662 commit_trans = journal->j_committing_transaction;
663 if (!commit_trans || commit_trans->t_tid != tid) {
664 ret = 1;
665 goto out;
666 }
667 /*
668 * Transaction is being committed and we already proceeded to
669 * submitting a flush to fs partition?
670 */
671 if (journal->j_fs_dev != journal->j_dev) {
672 if (!commit_trans->t_need_data_flush ||
673 commit_trans->t_state >= T_COMMIT_DFLUSH)
674 goto out;
675 } else {
676 if (commit_trans->t_state >= T_COMMIT_JFLUSH)
677 goto out;
678 }
679 ret = 1;
680out:
681 read_unlock(&journal->j_state_lock);
682 return ret;
683}
684EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
685
686/*
687 * Wait for a specified commit to complete.
688 * The caller may not hold the journal lock.
689 */
690int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
691{
692 int err = 0;
693
694 jbd2_might_wait_for_commit(journal);
695 read_lock(&journal->j_state_lock);
696#ifdef CONFIG_JBD2_DEBUG
697 if (!tid_geq(journal->j_commit_request, tid)) {
698 printk(KERN_ERR
699 "%s: error: j_commit_request=%d, tid=%d\n",
700 __func__, journal->j_commit_request, tid);
701 }
702#endif
703 while (tid_gt(tid, journal->j_commit_sequence)) {
704 jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
705 tid, journal->j_commit_sequence);
706 read_unlock(&journal->j_state_lock);
707 wake_up(&journal->j_wait_commit);
708 wait_event(journal->j_wait_done_commit,
709 !tid_gt(tid, journal->j_commit_sequence));
710 read_lock(&journal->j_state_lock);
711 }
712 read_unlock(&journal->j_state_lock);
713
714 if (unlikely(is_journal_aborted(journal)))
715 err = -EIO;
716 return err;
717}
718
719/*
720 * When this function returns the transaction corresponding to tid
721 * will be completed. If the transaction has currently running, start
722 * committing that transaction before waiting for it to complete. If
723 * the transaction id is stale, it is by definition already completed,
724 * so just return SUCCESS.
725 */
726int jbd2_complete_transaction(journal_t *journal, tid_t tid)
727{
728 int need_to_wait = 1;
729
730 read_lock(&journal->j_state_lock);
731 if (journal->j_running_transaction &&
732 journal->j_running_transaction->t_tid == tid) {
733 if (journal->j_commit_request != tid) {
734 /* transaction not yet started, so request it */
735 read_unlock(&journal->j_state_lock);
736 jbd2_log_start_commit(journal, tid);
737 goto wait_commit;
738 }
739 } else if (!(journal->j_committing_transaction &&
740 journal->j_committing_transaction->t_tid == tid))
741 need_to_wait = 0;
742 read_unlock(&journal->j_state_lock);
743 if (!need_to_wait)
744 return 0;
745wait_commit:
746 return jbd2_log_wait_commit(journal, tid);
747}
748EXPORT_SYMBOL(jbd2_complete_transaction);
749
750/*
751 * Log buffer allocation routines:
752 */
753
754int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
755{
756 unsigned long blocknr;
757
758 write_lock(&journal->j_state_lock);
759 J_ASSERT(journal->j_free > 1);
760
761 blocknr = journal->j_head;
762 journal->j_head++;
763 journal->j_free--;
764 if (journal->j_head == journal->j_last)
765 journal->j_head = journal->j_first;
766 write_unlock(&journal->j_state_lock);
767 return jbd2_journal_bmap(journal, blocknr, retp);
768}
769
770/*
771 * Conversion of logical to physical block numbers for the journal
772 *
773 * On external journals the journal blocks are identity-mapped, so
774 * this is a no-op. If needed, we can use j_blk_offset - everything is
775 * ready.
776 */
777int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
778 unsigned long long *retp)
779{
780 int err = 0;
781 unsigned long long ret;
782
783 if (journal->j_inode) {
784 ret = bmap(journal->j_inode, blocknr);
785 if (ret)
786 *retp = ret;
787 else {
788 printk(KERN_ALERT "%s: journal block not found "
789 "at offset %lu on %s\n",
790 __func__, blocknr, journal->j_devname);
791 err = -EIO;
792 __journal_abort_soft(journal, err);
793 }
794 } else {
795 *retp = blocknr; /* +journal->j_blk_offset */
796 }
797 return err;
798}
799
800/*
801 * We play buffer_head aliasing tricks to write data/metadata blocks to
802 * the journal without copying their contents, but for journal
803 * descriptor blocks we do need to generate bona fide buffers.
804 *
805 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
806 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
807 * But we don't bother doing that, so there will be coherency problems with
808 * mmaps of blockdevs which hold live JBD-controlled filesystems.
809 */
810struct buffer_head *
811jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
812{
813 journal_t *journal = transaction->t_journal;
814 struct buffer_head *bh;
815 unsigned long long blocknr;
816 journal_header_t *header;
817 int err;
818
819 err = jbd2_journal_next_log_block(journal, &blocknr);
820
821 if (err)
822 return NULL;
823
824 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
825 if (!bh)
826 return NULL;
827 lock_buffer(bh);
828 memset(bh->b_data, 0, journal->j_blocksize);
829 header = (journal_header_t *)bh->b_data;
830 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
831 header->h_blocktype = cpu_to_be32(type);
832 header->h_sequence = cpu_to_be32(transaction->t_tid);
833 set_buffer_uptodate(bh);
834 unlock_buffer(bh);
835 BUFFER_TRACE(bh, "return this buffer");
836 return bh;
837}
838
839void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
840{
841 struct jbd2_journal_block_tail *tail;
842 __u32 csum;
843
844 if (!jbd2_journal_has_csum_v2or3(j))
845 return;
846
847 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
848 sizeof(struct jbd2_journal_block_tail));
849 tail->t_checksum = 0;
850 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
851 tail->t_checksum = cpu_to_be32(csum);
852}
853
854/*
855 * Return tid of the oldest transaction in the journal and block in the journal
856 * where the transaction starts.
857 *
858 * If the journal is now empty, return which will be the next transaction ID
859 * we will write and where will that transaction start.
860 *
861 * The return value is 0 if journal tail cannot be pushed any further, 1 if
862 * it can.
863 */
864int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
865 unsigned long *block)
866{
867 transaction_t *transaction;
868 int ret;
869
870 read_lock(&journal->j_state_lock);
871 spin_lock(&journal->j_list_lock);
872 transaction = journal->j_checkpoint_transactions;
873 if (transaction) {
874 *tid = transaction->t_tid;
875 *block = transaction->t_log_start;
876 } else if ((transaction = journal->j_committing_transaction) != NULL) {
877 *tid = transaction->t_tid;
878 *block = transaction->t_log_start;
879 } else if ((transaction = journal->j_running_transaction) != NULL) {
880 *tid = transaction->t_tid;
881 *block = journal->j_head;
882 } else {
883 *tid = journal->j_transaction_sequence;
884 *block = journal->j_head;
885 }
886 ret = tid_gt(*tid, journal->j_tail_sequence);
887 spin_unlock(&journal->j_list_lock);
888 read_unlock(&journal->j_state_lock);
889
890 return ret;
891}
892
893/*
894 * Update information in journal structure and in on disk journal superblock
895 * about log tail. This function does not check whether information passed in
896 * really pushes log tail further. It's responsibility of the caller to make
897 * sure provided log tail information is valid (e.g. by holding
898 * j_checkpoint_mutex all the time between computing log tail and calling this
899 * function as is the case with jbd2_cleanup_journal_tail()).
900 *
901 * Requires j_checkpoint_mutex
902 */
903int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
904{
905 unsigned long freed;
906 int ret;
907
908 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
909
910 /*
911 * We cannot afford for write to remain in drive's caches since as
912 * soon as we update j_tail, next transaction can start reusing journal
913 * space and if we lose sb update during power failure we'd replay
914 * old transaction with possibly newly overwritten data.
915 */
916 ret = jbd2_journal_update_sb_log_tail(journal, tid, block, REQ_FUA);
917 if (ret)
918 goto out;
919
920 write_lock(&journal->j_state_lock);
921 freed = block - journal->j_tail;
922 if (block < journal->j_tail)
923 freed += journal->j_last - journal->j_first;
924
925 trace_jbd2_update_log_tail(journal, tid, block, freed);
926 jbd_debug(1,
927 "Cleaning journal tail from %d to %d (offset %lu), "
928 "freeing %lu\n",
929 journal->j_tail_sequence, tid, block, freed);
930
931 journal->j_free += freed;
932 journal->j_tail_sequence = tid;
933 journal->j_tail = block;
934 write_unlock(&journal->j_state_lock);
935
936out:
937 return ret;
938}
939
940/*
941 * This is a variaon of __jbd2_update_log_tail which checks for validity of
942 * provided log tail and locks j_checkpoint_mutex. So it is safe against races
943 * with other threads updating log tail.
944 */
945void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
946{
947 mutex_lock(&journal->j_checkpoint_mutex);
948 if (tid_gt(tid, journal->j_tail_sequence))
949 __jbd2_update_log_tail(journal, tid, block);
950 mutex_unlock(&journal->j_checkpoint_mutex);
951}
952
953struct jbd2_stats_proc_session {
954 journal_t *journal;
955 struct transaction_stats_s *stats;
956 int start;
957 int max;
958};
959
960static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
961{
962 return *pos ? NULL : SEQ_START_TOKEN;
963}
964
965static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
966{
967 return NULL;
968}
969
970static int jbd2_seq_info_show(struct seq_file *seq, void *v)
971{
972 struct jbd2_stats_proc_session *s = seq->private;
973
974 if (v != SEQ_START_TOKEN)
975 return 0;
976 seq_printf(seq, "%lu transactions (%lu requested), "
977 "each up to %u blocks\n",
978 s->stats->ts_tid, s->stats->ts_requested,
979 s->journal->j_max_transaction_buffers);
980 if (s->stats->ts_tid == 0)
981 return 0;
982 seq_printf(seq, "average: \n %ums waiting for transaction\n",
983 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
984 seq_printf(seq, " %ums request delay\n",
985 (s->stats->ts_requested == 0) ? 0 :
986 jiffies_to_msecs(s->stats->run.rs_request_delay /
987 s->stats->ts_requested));
988 seq_printf(seq, " %ums running transaction\n",
989 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
990 seq_printf(seq, " %ums transaction was being locked\n",
991 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
992 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
993 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
994 seq_printf(seq, " %ums logging transaction\n",
995 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
996 seq_printf(seq, " %lluus average transaction commit time\n",
997 div_u64(s->journal->j_average_commit_time, 1000));
998 seq_printf(seq, " %lu handles per transaction\n",
999 s->stats->run.rs_handle_count / s->stats->ts_tid);
1000 seq_printf(seq, " %lu blocks per transaction\n",
1001 s->stats->run.rs_blocks / s->stats->ts_tid);
1002 seq_printf(seq, " %lu logged blocks per transaction\n",
1003 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1004 return 0;
1005}
1006
1007static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1008{
1009}
1010
1011static const struct seq_operations jbd2_seq_info_ops = {
1012 .start = jbd2_seq_info_start,
1013 .next = jbd2_seq_info_next,
1014 .stop = jbd2_seq_info_stop,
1015 .show = jbd2_seq_info_show,
1016};
1017
1018static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1019{
1020 journal_t *journal = PDE_DATA(inode);
1021 struct jbd2_stats_proc_session *s;
1022 int rc, size;
1023
1024 s = kmalloc(sizeof(*s), GFP_KERNEL);
1025 if (s == NULL)
1026 return -ENOMEM;
1027 size = sizeof(struct transaction_stats_s);
1028 s->stats = kmalloc(size, GFP_KERNEL);
1029 if (s->stats == NULL) {
1030 kfree(s);
1031 return -ENOMEM;
1032 }
1033 spin_lock(&journal->j_history_lock);
1034 memcpy(s->stats, &journal->j_stats, size);
1035 s->journal = journal;
1036 spin_unlock(&journal->j_history_lock);
1037
1038 rc = seq_open(file, &jbd2_seq_info_ops);
1039 if (rc == 0) {
1040 struct seq_file *m = file->private_data;
1041 m->private = s;
1042 } else {
1043 kfree(s->stats);
1044 kfree(s);
1045 }
1046 return rc;
1047
1048}
1049
1050static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1051{
1052 struct seq_file *seq = file->private_data;
1053 struct jbd2_stats_proc_session *s = seq->private;
1054 kfree(s->stats);
1055 kfree(s);
1056 return seq_release(inode, file);
1057}
1058
1059static const struct file_operations jbd2_seq_info_fops = {
1060 .owner = THIS_MODULE,
1061 .open = jbd2_seq_info_open,
1062 .read = seq_read,
1063 .llseek = seq_lseek,
1064 .release = jbd2_seq_info_release,
1065};
1066
1067static struct proc_dir_entry *proc_jbd2_stats;
1068
1069static void jbd2_stats_proc_init(journal_t *journal)
1070{
1071 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1072 if (journal->j_proc_entry) {
1073 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1074 &jbd2_seq_info_fops, journal);
1075 }
1076}
1077
1078static void jbd2_stats_proc_exit(journal_t *journal)
1079{
1080 remove_proc_entry("info", journal->j_proc_entry);
1081 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1082}
1083
1084/*
1085 * Management for journal control blocks: functions to create and
1086 * destroy journal_t structures, and to initialise and read existing
1087 * journal blocks from disk. */
1088
1089/* First: create and setup a journal_t object in memory. We initialise
1090 * very few fields yet: that has to wait until we have created the
1091 * journal structures from from scratch, or loaded them from disk. */
1092
1093static journal_t *journal_init_common(struct block_device *bdev,
1094 struct block_device *fs_dev,
1095 unsigned long long start, int len, int blocksize)
1096{
1097 static struct lock_class_key jbd2_trans_commit_key;
1098 journal_t *journal;
1099 int err;
1100 struct buffer_head *bh;
1101 int n;
1102
1103 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1104 if (!journal)
1105 return NULL;
1106
1107 init_waitqueue_head(&journal->j_wait_transaction_locked);
1108 init_waitqueue_head(&journal->j_wait_done_commit);
1109 init_waitqueue_head(&journal->j_wait_commit);
1110 init_waitqueue_head(&journal->j_wait_updates);
1111 init_waitqueue_head(&journal->j_wait_reserved);
1112 mutex_init(&journal->j_barrier);
1113 mutex_init(&journal->j_checkpoint_mutex);
1114 spin_lock_init(&journal->j_revoke_lock);
1115 spin_lock_init(&journal->j_list_lock);
1116 rwlock_init(&journal->j_state_lock);
1117
1118 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1119 journal->j_min_batch_time = 0;
1120 journal->j_max_batch_time = 15000; /* 15ms */
1121 atomic_set(&journal->j_reserved_credits, 0);
1122
1123 /* The journal is marked for error until we succeed with recovery! */
1124 journal->j_flags = JBD2_ABORT;
1125
1126 /* Set up a default-sized revoke table for the new mount. */
1127 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1128 if (err)
1129 goto err_cleanup;
1130
1131 spin_lock_init(&journal->j_history_lock);
1132
1133 lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
1134 &jbd2_trans_commit_key, 0);
1135
1136 /* journal descriptor can store up to n blocks -bzzz */
1137 journal->j_blocksize = blocksize;
1138 journal->j_dev = bdev;
1139 journal->j_fs_dev = fs_dev;
1140 journal->j_blk_offset = start;
1141 journal->j_maxlen = len;
1142 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1143 journal->j_wbufsize = n;
1144 journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
1145 GFP_KERNEL);
1146 if (!journal->j_wbuf)
1147 goto err_cleanup;
1148
1149 bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize);
1150 if (!bh) {
1151 pr_err("%s: Cannot get buffer for journal superblock\n",
1152 __func__);
1153 goto err_cleanup;
1154 }
1155 journal->j_sb_buffer = bh;
1156 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1157
1158 return journal;
1159
1160err_cleanup:
1161 kfree(journal->j_wbuf);
1162 jbd2_journal_destroy_revoke(journal);
1163 kfree(journal);
1164 return NULL;
1165}
1166
1167/* jbd2_journal_init_dev and jbd2_journal_init_inode:
1168 *
1169 * Create a journal structure assigned some fixed set of disk blocks to
1170 * the journal. We don't actually touch those disk blocks yet, but we
1171 * need to set up all of the mapping information to tell the journaling
1172 * system where the journal blocks are.
1173 *
1174 */
1175
1176/**
1177 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1178 * @bdev: Block device on which to create the journal
1179 * @fs_dev: Device which hold journalled filesystem for this journal.
1180 * @start: Block nr Start of journal.
1181 * @len: Length of the journal in blocks.
1182 * @blocksize: blocksize of journalling device
1183 *
1184 * Returns: a newly created journal_t *
1185 *
1186 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1187 * range of blocks on an arbitrary block device.
1188 *
1189 */
1190journal_t *jbd2_journal_init_dev(struct block_device *bdev,
1191 struct block_device *fs_dev,
1192 unsigned long long start, int len, int blocksize)
1193{
1194 journal_t *journal;
1195
1196 journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
1197 if (!journal)
1198 return NULL;
1199
1200 bdevname(journal->j_dev, journal->j_devname);
1201 strreplace(journal->j_devname, '/', '!');
1202 jbd2_stats_proc_init(journal);
1203
1204 return journal;
1205}
1206
1207/**
1208 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1209 * @inode: An inode to create the journal in
1210 *
1211 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1212 * the journal. The inode must exist already, must support bmap() and
1213 * must have all data blocks preallocated.
1214 */
1215journal_t *jbd2_journal_init_inode(struct inode *inode)
1216{
1217 journal_t *journal;
1218 char *p;
1219 unsigned long long blocknr;
1220
1221 blocknr = bmap(inode, 0);
1222 if (!blocknr) {
1223 pr_err("%s: Cannot locate journal superblock\n",
1224 __func__);
1225 return NULL;
1226 }
1227
1228 jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
1229 inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
1230 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1231
1232 journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
1233 blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
1234 inode->i_sb->s_blocksize);
1235 if (!journal)
1236 return NULL;
1237
1238 journal->j_inode = inode;
1239 bdevname(journal->j_dev, journal->j_devname);
1240 p = strreplace(journal->j_devname, '/', '!');
1241 sprintf(p, "-%lu", journal->j_inode->i_ino);
1242 jbd2_stats_proc_init(journal);
1243
1244 return journal;
1245}
1246
1247/*
1248 * If the journal init or create aborts, we need to mark the journal
1249 * superblock as being NULL to prevent the journal destroy from writing
1250 * back a bogus superblock.
1251 */
1252static void journal_fail_superblock (journal_t *journal)
1253{
1254 struct buffer_head *bh = journal->j_sb_buffer;
1255 brelse(bh);
1256 journal->j_sb_buffer = NULL;
1257}
1258
1259/*
1260 * Given a journal_t structure, initialise the various fields for
1261 * startup of a new journaling session. We use this both when creating
1262 * a journal, and after recovering an old journal to reset it for
1263 * subsequent use.
1264 */
1265
1266static int journal_reset(journal_t *journal)
1267{
1268 journal_superblock_t *sb = journal->j_superblock;
1269 unsigned long long first, last;
1270
1271 first = be32_to_cpu(sb->s_first);
1272 last = be32_to_cpu(sb->s_maxlen);
1273 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1274 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1275 first, last);
1276 journal_fail_superblock(journal);
1277 return -EINVAL;
1278 }
1279
1280 journal->j_first = first;
1281 journal->j_last = last;
1282
1283 journal->j_head = first;
1284 journal->j_tail = first;
1285 journal->j_free = last - first;
1286
1287 journal->j_tail_sequence = journal->j_transaction_sequence;
1288 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1289 journal->j_commit_request = journal->j_commit_sequence;
1290
1291 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1292
1293 /*
1294 * As a special case, if the on-disk copy is already marked as needing
1295 * no recovery (s_start == 0), then we can safely defer the superblock
1296 * update until the next commit by setting JBD2_FLUSHED. This avoids
1297 * attempting a write to a potential-readonly device.
1298 */
1299 if (sb->s_start == 0) {
1300 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1301 "(start %ld, seq %d, errno %d)\n",
1302 journal->j_tail, journal->j_tail_sequence,
1303 journal->j_errno);
1304 journal->j_flags |= JBD2_FLUSHED;
1305 } else {
1306 /* Lock here to make assertions happy... */
1307 mutex_lock(&journal->j_checkpoint_mutex);
1308 /*
1309 * Update log tail information. We use REQ_FUA since new
1310 * transaction will start reusing journal space and so we
1311 * must make sure information about current log tail is on
1312 * disk before that.
1313 */
1314 jbd2_journal_update_sb_log_tail(journal,
1315 journal->j_tail_sequence,
1316 journal->j_tail,
1317 REQ_FUA);
1318 mutex_unlock(&journal->j_checkpoint_mutex);
1319 }
1320 return jbd2_journal_start_thread(journal);
1321}
1322
1323static int jbd2_write_superblock(journal_t *journal, int write_flags)
1324{
1325 struct buffer_head *bh = journal->j_sb_buffer;
1326 journal_superblock_t *sb = journal->j_superblock;
1327 int ret;
1328
1329 trace_jbd2_write_superblock(journal, write_flags);
1330 if (!(journal->j_flags & JBD2_BARRIER))
1331 write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1332 lock_buffer(bh);
1333 if (buffer_write_io_error(bh)) {
1334 /*
1335 * Oh, dear. A previous attempt to write the journal
1336 * superblock failed. This could happen because the
1337 * USB device was yanked out. Or it could happen to
1338 * be a transient write error and maybe the block will
1339 * be remapped. Nothing we can do but to retry the
1340 * write and hope for the best.
1341 */
1342 printk(KERN_ERR "JBD2: previous I/O error detected "
1343 "for journal superblock update for %s.\n",
1344 journal->j_devname);
1345 clear_buffer_write_io_error(bh);
1346 set_buffer_uptodate(bh);
1347 }
1348 jbd2_superblock_csum_set(journal, sb);
1349 get_bh(bh);
1350 bh->b_end_io = end_buffer_write_sync;
1351 ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
1352 wait_on_buffer(bh);
1353 if (buffer_write_io_error(bh)) {
1354 clear_buffer_write_io_error(bh);
1355 set_buffer_uptodate(bh);
1356 ret = -EIO;
1357 }
1358 if (ret) {
1359 printk(KERN_ERR "JBD2: Error %d detected when updating "
1360 "journal superblock for %s.\n", ret,
1361 journal->j_devname);
1362 jbd2_journal_abort(journal, ret);
1363 }
1364
1365 return ret;
1366}
1367
1368/**
1369 * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1370 * @journal: The journal to update.
1371 * @tail_tid: TID of the new transaction at the tail of the log
1372 * @tail_block: The first block of the transaction at the tail of the log
1373 * @write_op: With which operation should we write the journal sb
1374 *
1375 * Update a journal's superblock information about log tail and write it to
1376 * disk, waiting for the IO to complete.
1377 */
1378int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1379 unsigned long tail_block, int write_op)
1380{
1381 journal_superblock_t *sb = journal->j_superblock;
1382 int ret;
1383
1384 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1385 jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1386 tail_block, tail_tid);
1387
1388 sb->s_sequence = cpu_to_be32(tail_tid);
1389 sb->s_start = cpu_to_be32(tail_block);
1390
1391 ret = jbd2_write_superblock(journal, write_op);
1392 if (ret)
1393 goto out;
1394
1395 /* Log is no longer empty */
1396 write_lock(&journal->j_state_lock);
1397 WARN_ON(!sb->s_sequence);
1398 journal->j_flags &= ~JBD2_FLUSHED;
1399 write_unlock(&journal->j_state_lock);
1400
1401out:
1402 return ret;
1403}
1404
1405/**
1406 * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1407 * @journal: The journal to update.
1408 * @write_op: With which operation should we write the journal sb
1409 *
1410 * Update a journal's dynamic superblock fields to show that journal is empty.
1411 * Write updated superblock to disk waiting for IO to complete.
1412 */
1413static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1414{
1415 journal_superblock_t *sb = journal->j_superblock;
1416
1417 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1418 read_lock(&journal->j_state_lock);
1419 /* Is it already empty? */
1420 if (sb->s_start == 0) {
1421 read_unlock(&journal->j_state_lock);
1422 return;
1423 }
1424 jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
1425 journal->j_tail_sequence);
1426
1427 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1428 sb->s_start = cpu_to_be32(0);
1429 read_unlock(&journal->j_state_lock);
1430
1431 jbd2_write_superblock(journal, write_op);
1432
1433 /* Log is no longer empty */
1434 write_lock(&journal->j_state_lock);
1435 journal->j_flags |= JBD2_FLUSHED;
1436 write_unlock(&journal->j_state_lock);
1437}
1438
1439
1440/**
1441 * jbd2_journal_update_sb_errno() - Update error in the journal.
1442 * @journal: The journal to update.
1443 *
1444 * Update a journal's errno. Write updated superblock to disk waiting for IO
1445 * to complete.
1446 */
1447void jbd2_journal_update_sb_errno(journal_t *journal)
1448{
1449 journal_superblock_t *sb = journal->j_superblock;
1450
1451 read_lock(&journal->j_state_lock);
1452 jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
1453 journal->j_errno);
1454 sb->s_errno = cpu_to_be32(journal->j_errno);
1455 read_unlock(&journal->j_state_lock);
1456
1457 jbd2_write_superblock(journal, REQ_FUA);
1458}
1459EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1460
1461/*
1462 * Read the superblock for a given journal, performing initial
1463 * validation of the format.
1464 */
1465static int journal_get_superblock(journal_t *journal)
1466{
1467 struct buffer_head *bh;
1468 journal_superblock_t *sb;
1469 int err = -EIO;
1470
1471 bh = journal->j_sb_buffer;
1472
1473 J_ASSERT(bh != NULL);
1474 if (!buffer_uptodate(bh)) {
1475 ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1476 wait_on_buffer(bh);
1477 if (!buffer_uptodate(bh)) {
1478 printk(KERN_ERR
1479 "JBD2: IO error reading journal superblock\n");
1480 goto out;
1481 }
1482 }
1483
1484 if (buffer_verified(bh))
1485 return 0;
1486
1487 sb = journal->j_superblock;
1488
1489 err = -EINVAL;
1490
1491 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1492 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1493 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1494 goto out;
1495 }
1496
1497 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1498 case JBD2_SUPERBLOCK_V1:
1499 journal->j_format_version = 1;
1500 break;
1501 case JBD2_SUPERBLOCK_V2:
1502 journal->j_format_version = 2;
1503 break;
1504 default:
1505 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1506 goto out;
1507 }
1508
1509 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1510 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1511 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1512 printk(KERN_WARNING "JBD2: journal file too short\n");
1513 goto out;
1514 }
1515
1516 if (be32_to_cpu(sb->s_first) == 0 ||
1517 be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
1518 printk(KERN_WARNING
1519 "JBD2: Invalid start block of journal: %u\n",
1520 be32_to_cpu(sb->s_first));
1521 goto out;
1522 }
1523
1524 if (jbd2_has_feature_csum2(journal) &&
1525 jbd2_has_feature_csum3(journal)) {
1526 /* Can't have checksum v2 and v3 at the same time! */
1527 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1528 "at the same time!\n");
1529 goto out;
1530 }
1531
1532 if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1533 jbd2_has_feature_checksum(journal)) {
1534 /* Can't have checksum v1 and v2 on at the same time! */
1535 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1536 "at the same time!\n");
1537 goto out;
1538 }
1539
1540 if (!jbd2_verify_csum_type(journal, sb)) {
1541 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1542 goto out;
1543 }
1544
1545 /* Load the checksum driver */
1546 if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1547 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1548 if (IS_ERR(journal->j_chksum_driver)) {
1549 printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1550 err = PTR_ERR(journal->j_chksum_driver);
1551 journal->j_chksum_driver = NULL;
1552 goto out;
1553 }
1554 }
1555
1556 /* Check superblock checksum */
1557 if (!jbd2_superblock_csum_verify(journal, sb)) {
1558 printk(KERN_ERR "JBD2: journal checksum error\n");
1559 err = -EFSBADCRC;
1560 goto out;
1561 }
1562
1563 /* Precompute checksum seed for all metadata */
1564 if (jbd2_journal_has_csum_v2or3(journal))
1565 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1566 sizeof(sb->s_uuid));
1567
1568 set_buffer_verified(bh);
1569
1570 return 0;
1571
1572out:
1573 journal_fail_superblock(journal);
1574 return err;
1575}
1576
1577/*
1578 * Load the on-disk journal superblock and read the key fields into the
1579 * journal_t.
1580 */
1581
1582static int load_superblock(journal_t *journal)
1583{
1584 int err;
1585 journal_superblock_t *sb;
1586
1587 err = journal_get_superblock(journal);
1588 if (err)
1589 return err;
1590
1591 sb = journal->j_superblock;
1592
1593 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1594 journal->j_tail = be32_to_cpu(sb->s_start);
1595 journal->j_first = be32_to_cpu(sb->s_first);
1596 journal->j_last = be32_to_cpu(sb->s_maxlen);
1597 journal->j_errno = be32_to_cpu(sb->s_errno);
1598
1599 return 0;
1600}
1601
1602
1603/**
1604 * int jbd2_journal_load() - Read journal from disk.
1605 * @journal: Journal to act on.
1606 *
1607 * Given a journal_t structure which tells us which disk blocks contain
1608 * a journal, read the journal from disk to initialise the in-memory
1609 * structures.
1610 */
1611int jbd2_journal_load(journal_t *journal)
1612{
1613 int err;
1614 journal_superblock_t *sb;
1615
1616 err = load_superblock(journal);
1617 if (err)
1618 return err;
1619
1620 sb = journal->j_superblock;
1621 /* If this is a V2 superblock, then we have to check the
1622 * features flags on it. */
1623
1624 if (journal->j_format_version >= 2) {
1625 if ((sb->s_feature_ro_compat &
1626 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1627 (sb->s_feature_incompat &
1628 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1629 printk(KERN_WARNING
1630 "JBD2: Unrecognised features on journal\n");
1631 return -EINVAL;
1632 }
1633 }
1634
1635 /*
1636 * Create a slab for this blocksize
1637 */
1638 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
1639 if (err)
1640 return err;
1641
1642 /* Let the recovery code check whether it needs to recover any
1643 * data from the journal. */
1644 if (jbd2_journal_recover(journal))
1645 goto recovery_error;
1646
1647 if (journal->j_failed_commit) {
1648 printk(KERN_ERR "JBD2: journal transaction %u on %s "
1649 "is corrupt.\n", journal->j_failed_commit,
1650 journal->j_devname);
1651 return -EFSCORRUPTED;
1652 }
1653
1654 /* OK, we've finished with the dynamic journal bits:
1655 * reinitialise the dynamic contents of the superblock in memory
1656 * and reset them on disk. */
1657 if (journal_reset(journal))
1658 goto recovery_error;
1659
1660 journal->j_flags &= ~JBD2_ABORT;
1661 journal->j_flags |= JBD2_LOADED;
1662 return 0;
1663
1664recovery_error:
1665 printk(KERN_WARNING "JBD2: recovery failed\n");
1666 return -EIO;
1667}
1668
1669/**
1670 * void jbd2_journal_destroy() - Release a journal_t structure.
1671 * @journal: Journal to act on.
1672 *
1673 * Release a journal_t structure once it is no longer in use by the
1674 * journaled object.
1675 * Return <0 if we couldn't clean up the journal.
1676 */
1677int jbd2_journal_destroy(journal_t *journal)
1678{
1679 int err = 0;
1680
1681 /* Wait for the commit thread to wake up and die. */
1682 journal_kill_thread(journal);
1683
1684 /* Force a final log commit */
1685 if (journal->j_running_transaction)
1686 jbd2_journal_commit_transaction(journal);
1687
1688 /* Force any old transactions to disk */
1689
1690 /* Totally anal locking here... */
1691 spin_lock(&journal->j_list_lock);
1692 while (journal->j_checkpoint_transactions != NULL) {
1693 spin_unlock(&journal->j_list_lock);
1694 mutex_lock(&journal->j_checkpoint_mutex);
1695 err = jbd2_log_do_checkpoint(journal);
1696 mutex_unlock(&journal->j_checkpoint_mutex);
1697 /*
1698 * If checkpointing failed, just free the buffers to avoid
1699 * looping forever
1700 */
1701 if (err) {
1702 jbd2_journal_destroy_checkpoint(journal);
1703 spin_lock(&journal->j_list_lock);
1704 break;
1705 }
1706 spin_lock(&journal->j_list_lock);
1707 }
1708
1709 J_ASSERT(journal->j_running_transaction == NULL);
1710 J_ASSERT(journal->j_committing_transaction == NULL);
1711 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1712 spin_unlock(&journal->j_list_lock);
1713
1714 if (journal->j_sb_buffer) {
1715 if (!is_journal_aborted(journal)) {
1716 mutex_lock(&journal->j_checkpoint_mutex);
1717
1718 write_lock(&journal->j_state_lock);
1719 journal->j_tail_sequence =
1720 ++journal->j_transaction_sequence;
1721 write_unlock(&journal->j_state_lock);
1722
1723 jbd2_mark_journal_empty(journal,
1724 REQ_PREFLUSH | REQ_FUA);
1725 mutex_unlock(&journal->j_checkpoint_mutex);
1726 } else
1727 err = -EIO;
1728 brelse(journal->j_sb_buffer);
1729 }
1730
1731 if (journal->j_proc_entry)
1732 jbd2_stats_proc_exit(journal);
1733 iput(journal->j_inode);
1734 if (journal->j_revoke)
1735 jbd2_journal_destroy_revoke(journal);
1736 if (journal->j_chksum_driver)
1737 crypto_free_shash(journal->j_chksum_driver);
1738 kfree(journal->j_wbuf);
1739 kfree(journal);
1740
1741 return err;
1742}
1743
1744
1745/**
1746 *int jbd2_journal_check_used_features () - Check if features specified are used.
1747 * @journal: Journal to check.
1748 * @compat: bitmask of compatible features
1749 * @ro: bitmask of features that force read-only mount
1750 * @incompat: bitmask of incompatible features
1751 *
1752 * Check whether the journal uses all of a given set of
1753 * features. Return true (non-zero) if it does.
1754 **/
1755
1756int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1757 unsigned long ro, unsigned long incompat)
1758{
1759 journal_superblock_t *sb;
1760
1761 if (!compat && !ro && !incompat)
1762 return 1;
1763 /* Load journal superblock if it is not loaded yet. */
1764 if (journal->j_format_version == 0 &&
1765 journal_get_superblock(journal) != 0)
1766 return 0;
1767 if (journal->j_format_version == 1)
1768 return 0;
1769
1770 sb = journal->j_superblock;
1771
1772 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1773 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1774 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1775 return 1;
1776
1777 return 0;
1778}
1779
1780/**
1781 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1782 * @journal: Journal to check.
1783 * @compat: bitmask of compatible features
1784 * @ro: bitmask of features that force read-only mount
1785 * @incompat: bitmask of incompatible features
1786 *
1787 * Check whether the journaling code supports the use of
1788 * all of a given set of features on this journal. Return true
1789 * (non-zero) if it can. */
1790
1791int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1792 unsigned long ro, unsigned long incompat)
1793{
1794 if (!compat && !ro && !incompat)
1795 return 1;
1796
1797 /* We can support any known requested features iff the
1798 * superblock is in version 2. Otherwise we fail to support any
1799 * extended sb features. */
1800
1801 if (journal->j_format_version != 2)
1802 return 0;
1803
1804 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1805 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1806 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1807 return 1;
1808
1809 return 0;
1810}
1811
1812/**
1813 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1814 * @journal: Journal to act on.
1815 * @compat: bitmask of compatible features
1816 * @ro: bitmask of features that force read-only mount
1817 * @incompat: bitmask of incompatible features
1818 *
1819 * Mark a given journal feature as present on the
1820 * superblock. Returns true if the requested features could be set.
1821 *
1822 */
1823
1824int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1825 unsigned long ro, unsigned long incompat)
1826{
1827#define INCOMPAT_FEATURE_ON(f) \
1828 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
1829#define COMPAT_FEATURE_ON(f) \
1830 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
1831 journal_superblock_t *sb;
1832
1833 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1834 return 1;
1835
1836 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1837 return 0;
1838
1839 /* If enabling v2 checksums, turn on v3 instead */
1840 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
1841 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
1842 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
1843 }
1844
1845 /* Asking for checksumming v3 and v1? Only give them v3. */
1846 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
1847 compat & JBD2_FEATURE_COMPAT_CHECKSUM)
1848 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
1849
1850 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1851 compat, ro, incompat);
1852
1853 sb = journal->j_superblock;
1854
1855 /* If enabling v3 checksums, update superblock */
1856 if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
1857 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
1858 sb->s_feature_compat &=
1859 ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
1860
1861 /* Load the checksum driver */
1862 if (journal->j_chksum_driver == NULL) {
1863 journal->j_chksum_driver = crypto_alloc_shash("crc32c",
1864 0, 0);
1865 if (IS_ERR(journal->j_chksum_driver)) {
1866 printk(KERN_ERR "JBD2: Cannot load crc32c "
1867 "driver.\n");
1868 journal->j_chksum_driver = NULL;
1869 return 0;
1870 }
1871
1872 /* Precompute checksum seed for all metadata */
1873 journal->j_csum_seed = jbd2_chksum(journal, ~0,
1874 sb->s_uuid,
1875 sizeof(sb->s_uuid));
1876 }
1877 }
1878
1879 /* If enabling v1 checksums, downgrade superblock */
1880 if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
1881 sb->s_feature_incompat &=
1882 ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
1883 JBD2_FEATURE_INCOMPAT_CSUM_V3);
1884
1885 sb->s_feature_compat |= cpu_to_be32(compat);
1886 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1887 sb->s_feature_incompat |= cpu_to_be32(incompat);
1888
1889 return 1;
1890#undef COMPAT_FEATURE_ON
1891#undef INCOMPAT_FEATURE_ON
1892}
1893
1894/*
1895 * jbd2_journal_clear_features () - Clear a given journal feature in the
1896 * superblock
1897 * @journal: Journal to act on.
1898 * @compat: bitmask of compatible features
1899 * @ro: bitmask of features that force read-only mount
1900 * @incompat: bitmask of incompatible features
1901 *
1902 * Clear a given journal feature as present on the
1903 * superblock.
1904 */
1905void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1906 unsigned long ro, unsigned long incompat)
1907{
1908 journal_superblock_t *sb;
1909
1910 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1911 compat, ro, incompat);
1912
1913 sb = journal->j_superblock;
1914
1915 sb->s_feature_compat &= ~cpu_to_be32(compat);
1916 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1917 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
1918}
1919EXPORT_SYMBOL(jbd2_journal_clear_features);
1920
1921/**
1922 * int jbd2_journal_flush () - Flush journal
1923 * @journal: Journal to act on.
1924 *
1925 * Flush all data for a given journal to disk and empty the journal.
1926 * Filesystems can use this when remounting readonly to ensure that
1927 * recovery does not need to happen on remount.
1928 */
1929
1930int jbd2_journal_flush(journal_t *journal)
1931{
1932 int err = 0;
1933 transaction_t *transaction = NULL;
1934
1935 write_lock(&journal->j_state_lock);
1936
1937 /* Force everything buffered to the log... */
1938 if (journal->j_running_transaction) {
1939 transaction = journal->j_running_transaction;
1940 __jbd2_log_start_commit(journal, transaction->t_tid);
1941 } else if (journal->j_committing_transaction)
1942 transaction = journal->j_committing_transaction;
1943
1944 /* Wait for the log commit to complete... */
1945 if (transaction) {
1946 tid_t tid = transaction->t_tid;
1947
1948 write_unlock(&journal->j_state_lock);
1949 jbd2_log_wait_commit(journal, tid);
1950 } else {
1951 write_unlock(&journal->j_state_lock);
1952 }
1953
1954 /* ...and flush everything in the log out to disk. */
1955 spin_lock(&journal->j_list_lock);
1956 while (!err && journal->j_checkpoint_transactions != NULL) {
1957 spin_unlock(&journal->j_list_lock);
1958 mutex_lock(&journal->j_checkpoint_mutex);
1959 err = jbd2_log_do_checkpoint(journal);
1960 mutex_unlock(&journal->j_checkpoint_mutex);
1961 spin_lock(&journal->j_list_lock);
1962 }
1963 spin_unlock(&journal->j_list_lock);
1964
1965 if (is_journal_aborted(journal))
1966 return -EIO;
1967
1968 mutex_lock(&journal->j_checkpoint_mutex);
1969 if (!err) {
1970 err = jbd2_cleanup_journal_tail(journal);
1971 if (err < 0) {
1972 mutex_unlock(&journal->j_checkpoint_mutex);
1973 goto out;
1974 }
1975 err = 0;
1976 }
1977
1978 /* Finally, mark the journal as really needing no recovery.
1979 * This sets s_start==0 in the underlying superblock, which is
1980 * the magic code for a fully-recovered superblock. Any future
1981 * commits of data to the journal will restore the current
1982 * s_start value. */
1983 jbd2_mark_journal_empty(journal, REQ_FUA);
1984 mutex_unlock(&journal->j_checkpoint_mutex);
1985 write_lock(&journal->j_state_lock);
1986 J_ASSERT(!journal->j_running_transaction);
1987 J_ASSERT(!journal->j_committing_transaction);
1988 J_ASSERT(!journal->j_checkpoint_transactions);
1989 J_ASSERT(journal->j_head == journal->j_tail);
1990 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
1991 write_unlock(&journal->j_state_lock);
1992out:
1993 return err;
1994}
1995
1996/**
1997 * int jbd2_journal_wipe() - Wipe journal contents
1998 * @journal: Journal to act on.
1999 * @write: flag (see below)
2000 *
2001 * Wipe out all of the contents of a journal, safely. This will produce
2002 * a warning if the journal contains any valid recovery information.
2003 * Must be called between journal_init_*() and jbd2_journal_load().
2004 *
2005 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2006 * we merely suppress recovery.
2007 */
2008
2009int jbd2_journal_wipe(journal_t *journal, int write)
2010{
2011 int err = 0;
2012
2013 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2014
2015 err = load_superblock(journal);
2016 if (err)
2017 return err;
2018
2019 if (!journal->j_tail)
2020 goto no_recovery;
2021
2022 printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2023 write ? "Clearing" : "Ignoring");
2024
2025 err = jbd2_journal_skip_recovery(journal);
2026 if (write) {
2027 /* Lock to make assertions happy... */
2028 mutex_lock(&journal->j_checkpoint_mutex);
2029 jbd2_mark_journal_empty(journal, REQ_FUA);
2030 mutex_unlock(&journal->j_checkpoint_mutex);
2031 }
2032
2033 no_recovery:
2034 return err;
2035}
2036
2037/*
2038 * Journal abort has very specific semantics, which we describe
2039 * for journal abort.
2040 *
2041 * Two internal functions, which provide abort to the jbd layer
2042 * itself are here.
2043 */
2044
2045/*
2046 * Quick version for internal journal use (doesn't lock the journal).
2047 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
2048 * and don't attempt to make any other journal updates.
2049 */
2050void __jbd2_journal_abort_hard(journal_t *journal)
2051{
2052 transaction_t *transaction;
2053
2054 if (journal->j_flags & JBD2_ABORT)
2055 return;
2056
2057 printk(KERN_ERR "Aborting journal on device %s.\n",
2058 journal->j_devname);
2059
2060 write_lock(&journal->j_state_lock);
2061 journal->j_flags |= JBD2_ABORT;
2062 transaction = journal->j_running_transaction;
2063 if (transaction)
2064 __jbd2_log_start_commit(journal, transaction->t_tid);
2065 write_unlock(&journal->j_state_lock);
2066}
2067
2068/* Soft abort: record the abort error status in the journal superblock,
2069 * but don't do any other IO. */
2070static void __journal_abort_soft (journal_t *journal, int errno)
2071{
2072 if (journal->j_flags & JBD2_ABORT)
2073 return;
2074
2075 if (!journal->j_errno)
2076 journal->j_errno = errno;
2077
2078 __jbd2_journal_abort_hard(journal);
2079
2080 if (errno) {
2081 jbd2_journal_update_sb_errno(journal);
2082 write_lock(&journal->j_state_lock);
2083 journal->j_flags |= JBD2_REC_ERR;
2084 write_unlock(&journal->j_state_lock);
2085 }
2086}
2087
2088/**
2089 * void jbd2_journal_abort () - Shutdown the journal immediately.
2090 * @journal: the journal to shutdown.
2091 * @errno: an error number to record in the journal indicating
2092 * the reason for the shutdown.
2093 *
2094 * Perform a complete, immediate shutdown of the ENTIRE
2095 * journal (not of a single transaction). This operation cannot be
2096 * undone without closing and reopening the journal.
2097 *
2098 * The jbd2_journal_abort function is intended to support higher level error
2099 * recovery mechanisms such as the ext2/ext3 remount-readonly error
2100 * mode.
2101 *
2102 * Journal abort has very specific semantics. Any existing dirty,
2103 * unjournaled buffers in the main filesystem will still be written to
2104 * disk by bdflush, but the journaling mechanism will be suspended
2105 * immediately and no further transaction commits will be honoured.
2106 *
2107 * Any dirty, journaled buffers will be written back to disk without
2108 * hitting the journal. Atomicity cannot be guaranteed on an aborted
2109 * filesystem, but we _do_ attempt to leave as much data as possible
2110 * behind for fsck to use for cleanup.
2111 *
2112 * Any attempt to get a new transaction handle on a journal which is in
2113 * ABORT state will just result in an -EROFS error return. A
2114 * jbd2_journal_stop on an existing handle will return -EIO if we have
2115 * entered abort state during the update.
2116 *
2117 * Recursive transactions are not disturbed by journal abort until the
2118 * final jbd2_journal_stop, which will receive the -EIO error.
2119 *
2120 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2121 * which will be recorded (if possible) in the journal superblock. This
2122 * allows a client to record failure conditions in the middle of a
2123 * transaction without having to complete the transaction to record the
2124 * failure to disk. ext3_error, for example, now uses this
2125 * functionality.
2126 *
2127 * Errors which originate from within the journaling layer will NOT
2128 * supply an errno; a null errno implies that absolutely no further
2129 * writes are done to the journal (unless there are any already in
2130 * progress).
2131 *
2132 */
2133
2134void jbd2_journal_abort(journal_t *journal, int errno)
2135{
2136 __journal_abort_soft(journal, errno);
2137}
2138
2139/**
2140 * int jbd2_journal_errno () - returns the journal's error state.
2141 * @journal: journal to examine.
2142 *
2143 * This is the errno number set with jbd2_journal_abort(), the last
2144 * time the journal was mounted - if the journal was stopped
2145 * without calling abort this will be 0.
2146 *
2147 * If the journal has been aborted on this mount time -EROFS will
2148 * be returned.
2149 */
2150int jbd2_journal_errno(journal_t *journal)
2151{
2152 int err;
2153
2154 read_lock(&journal->j_state_lock);
2155 if (journal->j_flags & JBD2_ABORT)
2156 err = -EROFS;
2157 else
2158 err = journal->j_errno;
2159 read_unlock(&journal->j_state_lock);
2160 return err;
2161}
2162
2163/**
2164 * int jbd2_journal_clear_err () - clears the journal's error state
2165 * @journal: journal to act on.
2166 *
2167 * An error must be cleared or acked to take a FS out of readonly
2168 * mode.
2169 */
2170int jbd2_journal_clear_err(journal_t *journal)
2171{
2172 int err = 0;
2173
2174 write_lock(&journal->j_state_lock);
2175 if (journal->j_flags & JBD2_ABORT)
2176 err = -EROFS;
2177 else
2178 journal->j_errno = 0;
2179 write_unlock(&journal->j_state_lock);
2180 return err;
2181}
2182
2183/**
2184 * void jbd2_journal_ack_err() - Ack journal err.
2185 * @journal: journal to act on.
2186 *
2187 * An error must be cleared or acked to take a FS out of readonly
2188 * mode.
2189 */
2190void jbd2_journal_ack_err(journal_t *journal)
2191{
2192 write_lock(&journal->j_state_lock);
2193 if (journal->j_errno)
2194 journal->j_flags |= JBD2_ACK_ERR;
2195 write_unlock(&journal->j_state_lock);
2196}
2197
2198int jbd2_journal_blocks_per_page(struct inode *inode)
2199{
2200 return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2201}
2202
2203/*
2204 * helper functions to deal with 32 or 64bit block numbers.
2205 */
2206size_t journal_tag_bytes(journal_t *journal)
2207{
2208 size_t sz;
2209
2210 if (jbd2_has_feature_csum3(journal))
2211 return sizeof(journal_block_tag3_t);
2212
2213 sz = sizeof(journal_block_tag_t);
2214
2215 if (jbd2_has_feature_csum2(journal))
2216 sz += sizeof(__u16);
2217
2218 if (jbd2_has_feature_64bit(journal))
2219 return sz;
2220 else
2221 return sz - sizeof(__u32);
2222}
2223
2224/*
2225 * JBD memory management
2226 *
2227 * These functions are used to allocate block-sized chunks of memory
2228 * used for making copies of buffer_head data. Very often it will be
2229 * page-sized chunks of data, but sometimes it will be in
2230 * sub-page-size chunks. (For example, 16k pages on Power systems
2231 * with a 4k block file system.) For blocks smaller than a page, we
2232 * use a SLAB allocator. There are slab caches for each block size,
2233 * which are allocated at mount time, if necessary, and we only free
2234 * (all of) the slab caches when/if the jbd2 module is unloaded. For
2235 * this reason we don't need to a mutex to protect access to
2236 * jbd2_slab[] allocating or releasing memory; only in
2237 * jbd2_journal_create_slab().
2238 */
2239#define JBD2_MAX_SLABS 8
2240static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2241
2242static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2243 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2244 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2245};
2246
2247
2248static void jbd2_journal_destroy_slabs(void)
2249{
2250 int i;
2251
2252 for (i = 0; i < JBD2_MAX_SLABS; i++) {
2253 if (jbd2_slab[i])
2254 kmem_cache_destroy(jbd2_slab[i]);
2255 jbd2_slab[i] = NULL;
2256 }
2257}
2258
2259static int jbd2_journal_create_slab(size_t size)
2260{
2261 static DEFINE_MUTEX(jbd2_slab_create_mutex);
2262 int i = order_base_2(size) - 10;
2263 size_t slab_size;
2264
2265 if (size == PAGE_SIZE)
2266 return 0;
2267
2268 if (i >= JBD2_MAX_SLABS)
2269 return -EINVAL;
2270
2271 if (unlikely(i < 0))
2272 i = 0;
2273 mutex_lock(&jbd2_slab_create_mutex);
2274 if (jbd2_slab[i]) {
2275 mutex_unlock(&jbd2_slab_create_mutex);
2276 return 0; /* Already created */
2277 }
2278
2279 slab_size = 1 << (i+10);
2280 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2281 slab_size, 0, NULL);
2282 mutex_unlock(&jbd2_slab_create_mutex);
2283 if (!jbd2_slab[i]) {
2284 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2285 return -ENOMEM;
2286 }
2287 return 0;
2288}
2289
2290static struct kmem_cache *get_slab(size_t size)
2291{
2292 int i = order_base_2(size) - 10;
2293
2294 BUG_ON(i >= JBD2_MAX_SLABS);
2295 if (unlikely(i < 0))
2296 i = 0;
2297 BUG_ON(jbd2_slab[i] == NULL);
2298 return jbd2_slab[i];
2299}
2300
2301void *jbd2_alloc(size_t size, gfp_t flags)
2302{
2303 void *ptr;
2304
2305 BUG_ON(size & (size-1)); /* Must be a power of 2 */
2306
2307 if (size < PAGE_SIZE)
2308 ptr = kmem_cache_alloc(get_slab(size), flags);
2309 else
2310 ptr = (void *)__get_free_pages(flags, get_order(size));
2311
2312 /* Check alignment; SLUB has gotten this wrong in the past,
2313 * and this can lead to user data corruption! */
2314 BUG_ON(((unsigned long) ptr) & (size-1));
2315
2316 return ptr;
2317}
2318
2319void jbd2_free(void *ptr, size_t size)
2320{
2321 if (size < PAGE_SIZE)
2322 kmem_cache_free(get_slab(size), ptr);
2323 else
2324 free_pages((unsigned long)ptr, get_order(size));
2325};
2326
2327/*
2328 * Journal_head storage management
2329 */
2330static struct kmem_cache *jbd2_journal_head_cache;
2331#ifdef CONFIG_JBD2_DEBUG
2332static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2333#endif
2334
2335static int jbd2_journal_init_journal_head_cache(void)
2336{
2337 int retval;
2338
2339 J_ASSERT(jbd2_journal_head_cache == NULL);
2340 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2341 sizeof(struct journal_head),
2342 0, /* offset */
2343 SLAB_TEMPORARY | SLAB_DESTROY_BY_RCU,
2344 NULL); /* ctor */
2345 retval = 0;
2346 if (!jbd2_journal_head_cache) {
2347 retval = -ENOMEM;
2348 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2349 }
2350 return retval;
2351}
2352
2353static void jbd2_journal_destroy_journal_head_cache(void)
2354{
2355 if (jbd2_journal_head_cache) {
2356 kmem_cache_destroy(jbd2_journal_head_cache);
2357 jbd2_journal_head_cache = NULL;
2358 }
2359}
2360
2361/*
2362 * journal_head splicing and dicing
2363 */
2364static struct journal_head *journal_alloc_journal_head(void)
2365{
2366 struct journal_head *ret;
2367
2368#ifdef CONFIG_JBD2_DEBUG
2369 atomic_inc(&nr_journal_heads);
2370#endif
2371 ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2372 if (!ret) {
2373 jbd_debug(1, "out of memory for journal_head\n");
2374 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2375 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2376 GFP_NOFS | __GFP_NOFAIL);
2377 }
2378 return ret;
2379}
2380
2381static void journal_free_journal_head(struct journal_head *jh)
2382{
2383#ifdef CONFIG_JBD2_DEBUG
2384 atomic_dec(&nr_journal_heads);
2385 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2386#endif
2387 kmem_cache_free(jbd2_journal_head_cache, jh);
2388}
2389
2390/*
2391 * A journal_head is attached to a buffer_head whenever JBD has an
2392 * interest in the buffer.
2393 *
2394 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2395 * is set. This bit is tested in core kernel code where we need to take
2396 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2397 * there.
2398 *
2399 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2400 *
2401 * When a buffer has its BH_JBD bit set it is immune from being released by
2402 * core kernel code, mainly via ->b_count.
2403 *
2404 * A journal_head is detached from its buffer_head when the journal_head's
2405 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2406 * transaction (b_cp_transaction) hold their references to b_jcount.
2407 *
2408 * Various places in the kernel want to attach a journal_head to a buffer_head
2409 * _before_ attaching the journal_head to a transaction. To protect the
2410 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2411 * journal_head's b_jcount refcount by one. The caller must call
2412 * jbd2_journal_put_journal_head() to undo this.
2413 *
2414 * So the typical usage would be:
2415 *
2416 * (Attach a journal_head if needed. Increments b_jcount)
2417 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2418 * ...
2419 * (Get another reference for transaction)
2420 * jbd2_journal_grab_journal_head(bh);
2421 * jh->b_transaction = xxx;
2422 * (Put original reference)
2423 * jbd2_journal_put_journal_head(jh);
2424 */
2425
2426/*
2427 * Give a buffer_head a journal_head.
2428 *
2429 * May sleep.
2430 */
2431struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2432{
2433 struct journal_head *jh;
2434 struct journal_head *new_jh = NULL;
2435
2436repeat:
2437 if (!buffer_jbd(bh))
2438 new_jh = journal_alloc_journal_head();
2439
2440 jbd_lock_bh_journal_head(bh);
2441 if (buffer_jbd(bh)) {
2442 jh = bh2jh(bh);
2443 } else {
2444 J_ASSERT_BH(bh,
2445 (atomic_read(&bh->b_count) > 0) ||
2446 (bh->b_page && bh->b_page->mapping));
2447
2448 if (!new_jh) {
2449 jbd_unlock_bh_journal_head(bh);
2450 goto repeat;
2451 }
2452
2453 jh = new_jh;
2454 new_jh = NULL; /* We consumed it */
2455 set_buffer_jbd(bh);
2456 bh->b_private = jh;
2457 jh->b_bh = bh;
2458 get_bh(bh);
2459 BUFFER_TRACE(bh, "added journal_head");
2460 }
2461 jh->b_jcount++;
2462 jbd_unlock_bh_journal_head(bh);
2463 if (new_jh)
2464 journal_free_journal_head(new_jh);
2465 return bh->b_private;
2466}
2467
2468/*
2469 * Grab a ref against this buffer_head's journal_head. If it ended up not
2470 * having a journal_head, return NULL
2471 */
2472struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2473{
2474 struct journal_head *jh = NULL;
2475
2476 jbd_lock_bh_journal_head(bh);
2477 if (buffer_jbd(bh)) {
2478 jh = bh2jh(bh);
2479 jh->b_jcount++;
2480 }
2481 jbd_unlock_bh_journal_head(bh);
2482 return jh;
2483}
2484
2485static void __journal_remove_journal_head(struct buffer_head *bh)
2486{
2487 struct journal_head *jh = bh2jh(bh);
2488
2489 J_ASSERT_JH(jh, jh->b_jcount >= 0);
2490 J_ASSERT_JH(jh, jh->b_transaction == NULL);
2491 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2492 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2493 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2494 J_ASSERT_BH(bh, buffer_jbd(bh));
2495 J_ASSERT_BH(bh, jh2bh(jh) == bh);
2496 BUFFER_TRACE(bh, "remove journal_head");
2497 if (jh->b_frozen_data) {
2498 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2499 jbd2_free(jh->b_frozen_data, bh->b_size);
2500 }
2501 if (jh->b_committed_data) {
2502 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2503 jbd2_free(jh->b_committed_data, bh->b_size);
2504 }
2505 bh->b_private = NULL;
2506 jh->b_bh = NULL; /* debug, really */
2507 clear_buffer_jbd(bh);
2508 journal_free_journal_head(jh);
2509}
2510
2511/*
2512 * Drop a reference on the passed journal_head. If it fell to zero then
2513 * release the journal_head from the buffer_head.
2514 */
2515void jbd2_journal_put_journal_head(struct journal_head *jh)
2516{
2517 struct buffer_head *bh = jh2bh(jh);
2518
2519 jbd_lock_bh_journal_head(bh);
2520 J_ASSERT_JH(jh, jh->b_jcount > 0);
2521 --jh->b_jcount;
2522 if (!jh->b_jcount) {
2523 __journal_remove_journal_head(bh);
2524 jbd_unlock_bh_journal_head(bh);
2525 __brelse(bh);
2526 } else
2527 jbd_unlock_bh_journal_head(bh);
2528}
2529
2530/*
2531 * Initialize jbd inode head
2532 */
2533void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2534{
2535 jinode->i_transaction = NULL;
2536 jinode->i_next_transaction = NULL;
2537 jinode->i_vfs_inode = inode;
2538 jinode->i_flags = 0;
2539 INIT_LIST_HEAD(&jinode->i_list);
2540}
2541
2542/*
2543 * Function to be called before we start removing inode from memory (i.e.,
2544 * clear_inode() is a fine place to be called from). It removes inode from
2545 * transaction's lists.
2546 */
2547void jbd2_journal_release_jbd_inode(journal_t *journal,
2548 struct jbd2_inode *jinode)
2549{
2550 if (!journal)
2551 return;
2552restart:
2553 spin_lock(&journal->j_list_lock);
2554 /* Is commit writing out inode - we have to wait */
2555 if (jinode->i_flags & JI_COMMIT_RUNNING) {
2556 wait_queue_head_t *wq;
2557 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2558 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2559 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2560 spin_unlock(&journal->j_list_lock);
2561 schedule();
2562 finish_wait(wq, &wait.wait);
2563 goto restart;
2564 }
2565
2566 if (jinode->i_transaction) {
2567 list_del(&jinode->i_list);
2568 jinode->i_transaction = NULL;
2569 }
2570 spin_unlock(&journal->j_list_lock);
2571}
2572
2573
2574#ifdef CONFIG_PROC_FS
2575
2576#define JBD2_STATS_PROC_NAME "fs/jbd2"
2577
2578static void __init jbd2_create_jbd_stats_proc_entry(void)
2579{
2580 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2581}
2582
2583static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2584{
2585 if (proc_jbd2_stats)
2586 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2587}
2588
2589#else
2590
2591#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2592#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2593
2594#endif
2595
2596struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
2597
2598static int __init jbd2_journal_init_handle_cache(void)
2599{
2600 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
2601 if (jbd2_handle_cache == NULL) {
2602 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
2603 return -ENOMEM;
2604 }
2605 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
2606 if (jbd2_inode_cache == NULL) {
2607 printk(KERN_EMERG "JBD2: failed to create inode cache\n");
2608 kmem_cache_destroy(jbd2_handle_cache);
2609 return -ENOMEM;
2610 }
2611 return 0;
2612}
2613
2614static void jbd2_journal_destroy_handle_cache(void)
2615{
2616 if (jbd2_handle_cache)
2617 kmem_cache_destroy(jbd2_handle_cache);
2618 if (jbd2_inode_cache)
2619 kmem_cache_destroy(jbd2_inode_cache);
2620
2621}
2622
2623/*
2624 * Module startup and shutdown
2625 */
2626
2627static int __init journal_init_caches(void)
2628{
2629 int ret;
2630
2631 ret = jbd2_journal_init_revoke_caches();
2632 if (ret == 0)
2633 ret = jbd2_journal_init_journal_head_cache();
2634 if (ret == 0)
2635 ret = jbd2_journal_init_handle_cache();
2636 if (ret == 0)
2637 ret = jbd2_journal_init_transaction_cache();
2638 return ret;
2639}
2640
2641static void jbd2_journal_destroy_caches(void)
2642{
2643 jbd2_journal_destroy_revoke_caches();
2644 jbd2_journal_destroy_journal_head_cache();
2645 jbd2_journal_destroy_handle_cache();
2646 jbd2_journal_destroy_transaction_cache();
2647 jbd2_journal_destroy_slabs();
2648}
2649
2650static int __init journal_init(void)
2651{
2652 int ret;
2653
2654 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2655
2656 ret = journal_init_caches();
2657 if (ret == 0) {
2658 jbd2_create_jbd_stats_proc_entry();
2659 } else {
2660 jbd2_journal_destroy_caches();
2661 }
2662 return ret;
2663}
2664
2665static void __exit journal_exit(void)
2666{
2667#ifdef CONFIG_JBD2_DEBUG
2668 int n = atomic_read(&nr_journal_heads);
2669 if (n)
2670 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
2671#endif
2672 jbd2_remove_jbd_stats_proc_entry();
2673 jbd2_journal_destroy_caches();
2674}
2675
2676MODULE_LICENSE("GPL");
2677module_init(journal_init);
2678module_exit(journal_exit);
2679