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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
54 ushort jbd2_journal_enable_debug __read_mostly;
55 EXPORT_SYMBOL(jbd2_journal_enable_debug);
56
57 module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
58 MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
59 #endif
60
61 EXPORT_SYMBOL(jbd2_journal_extend);
62 EXPORT_SYMBOL(jbd2_journal_stop);
63 EXPORT_SYMBOL(jbd2_journal_lock_updates);
64 EXPORT_SYMBOL(jbd2_journal_unlock_updates);
65 EXPORT_SYMBOL(jbd2_journal_get_write_access);
66 EXPORT_SYMBOL(jbd2_journal_get_create_access);
67 EXPORT_SYMBOL(jbd2_journal_get_undo_access);
68 EXPORT_SYMBOL(jbd2_journal_set_triggers);
69 EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
70 EXPORT_SYMBOL(jbd2_journal_forget);
71 #if 0
72 EXPORT_SYMBOL(journal_sync_buffer);
73 #endif
74 EXPORT_SYMBOL(jbd2_journal_flush);
75 EXPORT_SYMBOL(jbd2_journal_revoke);
76
77 EXPORT_SYMBOL(jbd2_journal_init_dev);
78 EXPORT_SYMBOL(jbd2_journal_init_inode);
79 EXPORT_SYMBOL(jbd2_journal_check_used_features);
80 EXPORT_SYMBOL(jbd2_journal_check_available_features);
81 EXPORT_SYMBOL(jbd2_journal_set_features);
82 EXPORT_SYMBOL(jbd2_journal_load);
83 EXPORT_SYMBOL(jbd2_journal_destroy);
84 EXPORT_SYMBOL(jbd2_journal_abort);
85 EXPORT_SYMBOL(jbd2_journal_errno);
86 EXPORT_SYMBOL(jbd2_journal_ack_err);
87 EXPORT_SYMBOL(jbd2_journal_clear_err);
88 EXPORT_SYMBOL(jbd2_log_wait_commit);
89 EXPORT_SYMBOL(jbd2_log_start_commit);
90 EXPORT_SYMBOL(jbd2_journal_start_commit);
91 EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
92 EXPORT_SYMBOL(jbd2_journal_wipe);
93 EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
94 EXPORT_SYMBOL(jbd2_journal_invalidatepage);
95 EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
96 EXPORT_SYMBOL(jbd2_journal_force_commit);
97 EXPORT_SYMBOL(jbd2_journal_inode_add_write);
98 EXPORT_SYMBOL(jbd2_journal_inode_add_wait);
99 EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
100 EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
101 EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
102 EXPORT_SYMBOL(jbd2_inode_cache);
103
104 static void __journal_abort_soft (journal_t *journal, int errno);
105 static int jbd2_journal_create_slab(size_t slab_size);
106
107 #ifdef CONFIG_JBD2_DEBUG
108 void __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 }
122 EXPORT_SYMBOL(__jbd2_debug);
123 #endif
124
125 /* Checksumming functions */
126 static 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
134 static __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
147 static 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
155 static 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
167 static 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
190 static 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
213 loop:
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
278 end_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
287 static 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
300 static 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
349 int 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);
381 repeat:
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 */
495 int __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
532 int 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 */
549 static 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 */
587 int 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 */
602 int 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 */
618 int 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 */
651 int 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;
680 out:
681 read_unlock(&journal->j_state_lock);
682 return ret;
683 }
684 EXPORT_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 */
690 int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
691 {
692 int err = 0;
693
694 read_lock(&journal->j_state_lock);
695 #ifdef CONFIG_JBD2_DEBUG
696 if (!tid_geq(journal->j_commit_request, tid)) {
697 printk(KERN_ERR
698 "%s: error: j_commit_request=%d, tid=%d\n",
699 __func__, journal->j_commit_request, tid);
700 }
701 #endif
702 while (tid_gt(tid, journal->j_commit_sequence)) {
703 jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
704 tid, journal->j_commit_sequence);
705 read_unlock(&journal->j_state_lock);
706 wake_up(&journal->j_wait_commit);
707 wait_event(journal->j_wait_done_commit,
708 !tid_gt(tid, journal->j_commit_sequence));
709 read_lock(&journal->j_state_lock);
710 }
711 read_unlock(&journal->j_state_lock);
712
713 if (unlikely(is_journal_aborted(journal)))
714 err = -EIO;
715 return err;
716 }
717
718 /*
719 * When this function returns the transaction corresponding to tid
720 * will be completed. If the transaction has currently running, start
721 * committing that transaction before waiting for it to complete. If
722 * the transaction id is stale, it is by definition already completed,
723 * so just return SUCCESS.
724 */
725 int jbd2_complete_transaction(journal_t *journal, tid_t tid)
726 {
727 int need_to_wait = 1;
728
729 read_lock(&journal->j_state_lock);
730 if (journal->j_running_transaction &&
731 journal->j_running_transaction->t_tid == tid) {
732 if (journal->j_commit_request != tid) {
733 /* transaction not yet started, so request it */
734 read_unlock(&journal->j_state_lock);
735 jbd2_log_start_commit(journal, tid);
736 goto wait_commit;
737 }
738 } else if (!(journal->j_committing_transaction &&
739 journal->j_committing_transaction->t_tid == tid))
740 need_to_wait = 0;
741 read_unlock(&journal->j_state_lock);
742 if (!need_to_wait)
743 return 0;
744 wait_commit:
745 return jbd2_log_wait_commit(journal, tid);
746 }
747 EXPORT_SYMBOL(jbd2_complete_transaction);
748
749 /*
750 * Log buffer allocation routines:
751 */
752
753 int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
754 {
755 unsigned long blocknr;
756
757 write_lock(&journal->j_state_lock);
758 J_ASSERT(journal->j_free > 1);
759
760 blocknr = journal->j_head;
761 journal->j_head++;
762 journal->j_free--;
763 if (journal->j_head == journal->j_last)
764 journal->j_head = journal->j_first;
765 write_unlock(&journal->j_state_lock);
766 return jbd2_journal_bmap(journal, blocknr, retp);
767 }
768
769 /*
770 * Conversion of logical to physical block numbers for the journal
771 *
772 * On external journals the journal blocks are identity-mapped, so
773 * this is a no-op. If needed, we can use j_blk_offset - everything is
774 * ready.
775 */
776 int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
777 unsigned long long *retp)
778 {
779 int err = 0;
780 unsigned long long ret;
781
782 if (journal->j_inode) {
783 ret = bmap(journal->j_inode, blocknr);
784 if (ret)
785 *retp = ret;
786 else {
787 printk(KERN_ALERT "%s: journal block not found "
788 "at offset %lu on %s\n",
789 __func__, blocknr, journal->j_devname);
790 err = -EIO;
791 __journal_abort_soft(journal, err);
792 }
793 } else {
794 *retp = blocknr; /* +journal->j_blk_offset */
795 }
796 return err;
797 }
798
799 /*
800 * We play buffer_head aliasing tricks to write data/metadata blocks to
801 * the journal without copying their contents, but for journal
802 * descriptor blocks we do need to generate bona fide buffers.
803 *
804 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
805 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
806 * But we don't bother doing that, so there will be coherency problems with
807 * mmaps of blockdevs which hold live JBD-controlled filesystems.
808 */
809 struct buffer_head *
810 jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
811 {
812 journal_t *journal = transaction->t_journal;
813 struct buffer_head *bh;
814 unsigned long long blocknr;
815 journal_header_t *header;
816 int err;
817
818 err = jbd2_journal_next_log_block(journal, &blocknr);
819
820 if (err)
821 return NULL;
822
823 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
824 if (!bh)
825 return NULL;
826 lock_buffer(bh);
827 memset(bh->b_data, 0, journal->j_blocksize);
828 header = (journal_header_t *)bh->b_data;
829 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
830 header->h_blocktype = cpu_to_be32(type);
831 header->h_sequence = cpu_to_be32(transaction->t_tid);
832 set_buffer_uptodate(bh);
833 unlock_buffer(bh);
834 BUFFER_TRACE(bh, "return this buffer");
835 return bh;
836 }
837
838 void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
839 {
840 struct jbd2_journal_block_tail *tail;
841 __u32 csum;
842
843 if (!jbd2_journal_has_csum_v2or3(j))
844 return;
845
846 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
847 sizeof(struct jbd2_journal_block_tail));
848 tail->t_checksum = 0;
849 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
850 tail->t_checksum = cpu_to_be32(csum);
851 }
852
853 /*
854 * Return tid of the oldest transaction in the journal and block in the journal
855 * where the transaction starts.
856 *
857 * If the journal is now empty, return which will be the next transaction ID
858 * we will write and where will that transaction start.
859 *
860 * The return value is 0 if journal tail cannot be pushed any further, 1 if
861 * it can.
862 */
863 int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
864 unsigned long *block)
865 {
866 transaction_t *transaction;
867 int ret;
868
869 read_lock(&journal->j_state_lock);
870 spin_lock(&journal->j_list_lock);
871 transaction = journal->j_checkpoint_transactions;
872 if (transaction) {
873 *tid = transaction->t_tid;
874 *block = transaction->t_log_start;
875 } else if ((transaction = journal->j_committing_transaction) != NULL) {
876 *tid = transaction->t_tid;
877 *block = transaction->t_log_start;
878 } else if ((transaction = journal->j_running_transaction) != NULL) {
879 *tid = transaction->t_tid;
880 *block = journal->j_head;
881 } else {
882 *tid = journal->j_transaction_sequence;
883 *block = journal->j_head;
884 }
885 ret = tid_gt(*tid, journal->j_tail_sequence);
886 spin_unlock(&journal->j_list_lock);
887 read_unlock(&journal->j_state_lock);
888
889 return ret;
890 }
891
892 /*
893 * Update information in journal structure and in on disk journal superblock
894 * about log tail. This function does not check whether information passed in
895 * really pushes log tail further. It's responsibility of the caller to make
896 * sure provided log tail information is valid (e.g. by holding
897 * j_checkpoint_mutex all the time between computing log tail and calling this
898 * function as is the case with jbd2_cleanup_journal_tail()).
899 *
900 * Requires j_checkpoint_mutex
901 */
902 int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
903 {
904 unsigned long freed;
905 int ret;
906
907 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
908
909 /*
910 * We cannot afford for write to remain in drive's caches since as
911 * soon as we update j_tail, next transaction can start reusing journal
912 * space and if we lose sb update during power failure we'd replay
913 * old transaction with possibly newly overwritten data.
914 */
915 ret = jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
916 if (ret)
917 goto out;
918
919 write_lock(&journal->j_state_lock);
920 freed = block - journal->j_tail;
921 if (block < journal->j_tail)
922 freed += journal->j_last - journal->j_first;
923
924 trace_jbd2_update_log_tail(journal, tid, block, freed);
925 jbd_debug(1,
926 "Cleaning journal tail from %d to %d (offset %lu), "
927 "freeing %lu\n",
928 journal->j_tail_sequence, tid, block, freed);
929
930 journal->j_free += freed;
931 journal->j_tail_sequence = tid;
932 journal->j_tail = block;
933 write_unlock(&journal->j_state_lock);
934
935 out:
936 return ret;
937 }
938
939 /*
940 * This is a variaon of __jbd2_update_log_tail which checks for validity of
941 * provided log tail and locks j_checkpoint_mutex. So it is safe against races
942 * with other threads updating log tail.
943 */
944 void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
945 {
946 mutex_lock(&journal->j_checkpoint_mutex);
947 if (tid_gt(tid, journal->j_tail_sequence))
948 __jbd2_update_log_tail(journal, tid, block);
949 mutex_unlock(&journal->j_checkpoint_mutex);
950 }
951
952 struct jbd2_stats_proc_session {
953 journal_t *journal;
954 struct transaction_stats_s *stats;
955 int start;
956 int max;
957 };
958
959 static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
960 {
961 return *pos ? NULL : SEQ_START_TOKEN;
962 }
963
964 static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
965 {
966 return NULL;
967 }
968
969 static int jbd2_seq_info_show(struct seq_file *seq, void *v)
970 {
971 struct jbd2_stats_proc_session *s = seq->private;
972
973 if (v != SEQ_START_TOKEN)
974 return 0;
975 seq_printf(seq, "%lu transactions (%lu requested), "
976 "each up to %u blocks\n",
977 s->stats->ts_tid, s->stats->ts_requested,
978 s->journal->j_max_transaction_buffers);
979 if (s->stats->ts_tid == 0)
980 return 0;
981 seq_printf(seq, "average: \n %ums waiting for transaction\n",
982 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
983 seq_printf(seq, " %ums request delay\n",
984 (s->stats->ts_requested == 0) ? 0 :
985 jiffies_to_msecs(s->stats->run.rs_request_delay /
986 s->stats->ts_requested));
987 seq_printf(seq, " %ums running transaction\n",
988 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
989 seq_printf(seq, " %ums transaction was being locked\n",
990 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
991 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
992 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
993 seq_printf(seq, " %ums logging transaction\n",
994 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
995 seq_printf(seq, " %lluus average transaction commit time\n",
996 div_u64(s->journal->j_average_commit_time, 1000));
997 seq_printf(seq, " %lu handles per transaction\n",
998 s->stats->run.rs_handle_count / s->stats->ts_tid);
999 seq_printf(seq, " %lu blocks per transaction\n",
1000 s->stats->run.rs_blocks / s->stats->ts_tid);
1001 seq_printf(seq, " %lu logged blocks per transaction\n",
1002 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1003 return 0;
1004 }
1005
1006 static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1007 {
1008 }
1009
1010 static const struct seq_operations jbd2_seq_info_ops = {
1011 .start = jbd2_seq_info_start,
1012 .next = jbd2_seq_info_next,
1013 .stop = jbd2_seq_info_stop,
1014 .show = jbd2_seq_info_show,
1015 };
1016
1017 static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1018 {
1019 journal_t *journal = PDE_DATA(inode);
1020 struct jbd2_stats_proc_session *s;
1021 int rc, size;
1022
1023 s = kmalloc(sizeof(*s), GFP_KERNEL);
1024 if (s == NULL)
1025 return -ENOMEM;
1026 size = sizeof(struct transaction_stats_s);
1027 s->stats = kmalloc(size, GFP_KERNEL);
1028 if (s->stats == NULL) {
1029 kfree(s);
1030 return -ENOMEM;
1031 }
1032 spin_lock(&journal->j_history_lock);
1033 memcpy(s->stats, &journal->j_stats, size);
1034 s->journal = journal;
1035 spin_unlock(&journal->j_history_lock);
1036
1037 rc = seq_open(file, &jbd2_seq_info_ops);
1038 if (rc == 0) {
1039 struct seq_file *m = file->private_data;
1040 m->private = s;
1041 } else {
1042 kfree(s->stats);
1043 kfree(s);
1044 }
1045 return rc;
1046
1047 }
1048
1049 static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1050 {
1051 struct seq_file *seq = file->private_data;
1052 struct jbd2_stats_proc_session *s = seq->private;
1053 kfree(s->stats);
1054 kfree(s);
1055 return seq_release(inode, file);
1056 }
1057
1058 static const struct file_operations jbd2_seq_info_fops = {
1059 .owner = THIS_MODULE,
1060 .open = jbd2_seq_info_open,
1061 .read = seq_read,
1062 .llseek = seq_lseek,
1063 .release = jbd2_seq_info_release,
1064 };
1065
1066 static struct proc_dir_entry *proc_jbd2_stats;
1067
1068 static void jbd2_stats_proc_init(journal_t *journal)
1069 {
1070 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1071 if (journal->j_proc_entry) {
1072 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1073 &jbd2_seq_info_fops, journal);
1074 }
1075 }
1076
1077 static void jbd2_stats_proc_exit(journal_t *journal)
1078 {
1079 remove_proc_entry("info", journal->j_proc_entry);
1080 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1081 }
1082
1083 /*
1084 * Management for journal control blocks: functions to create and
1085 * destroy journal_t structures, and to initialise and read existing
1086 * journal blocks from disk. */
1087
1088 /* First: create and setup a journal_t object in memory. We initialise
1089 * very few fields yet: that has to wait until we have created the
1090 * journal structures from from scratch, or loaded them from disk. */
1091
1092 static journal_t * journal_init_common (void)
1093 {
1094 journal_t *journal;
1095 int err;
1096
1097 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1098 if (!journal)
1099 return NULL;
1100
1101 init_waitqueue_head(&journal->j_wait_transaction_locked);
1102 init_waitqueue_head(&journal->j_wait_done_commit);
1103 init_waitqueue_head(&journal->j_wait_commit);
1104 init_waitqueue_head(&journal->j_wait_updates);
1105 init_waitqueue_head(&journal->j_wait_reserved);
1106 mutex_init(&journal->j_barrier);
1107 mutex_init(&journal->j_checkpoint_mutex);
1108 spin_lock_init(&journal->j_revoke_lock);
1109 spin_lock_init(&journal->j_list_lock);
1110 rwlock_init(&journal->j_state_lock);
1111
1112 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1113 journal->j_min_batch_time = 0;
1114 journal->j_max_batch_time = 15000; /* 15ms */
1115 atomic_set(&journal->j_reserved_credits, 0);
1116
1117 /* The journal is marked for error until we succeed with recovery! */
1118 journal->j_flags = JBD2_ABORT;
1119
1120 /* Set up a default-sized revoke table for the new mount. */
1121 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1122 if (err) {
1123 kfree(journal);
1124 return NULL;
1125 }
1126
1127 spin_lock_init(&journal->j_history_lock);
1128
1129 return journal;
1130 }
1131
1132 /* jbd2_journal_init_dev and jbd2_journal_init_inode:
1133 *
1134 * Create a journal structure assigned some fixed set of disk blocks to
1135 * the journal. We don't actually touch those disk blocks yet, but we
1136 * need to set up all of the mapping information to tell the journaling
1137 * system where the journal blocks are.
1138 *
1139 */
1140
1141 /**
1142 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1143 * @bdev: Block device on which to create the journal
1144 * @fs_dev: Device which hold journalled filesystem for this journal.
1145 * @start: Block nr Start of journal.
1146 * @len: Length of the journal in blocks.
1147 * @blocksize: blocksize of journalling device
1148 *
1149 * Returns: a newly created journal_t *
1150 *
1151 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1152 * range of blocks on an arbitrary block device.
1153 *
1154 */
1155 journal_t * jbd2_journal_init_dev(struct block_device *bdev,
1156 struct block_device *fs_dev,
1157 unsigned long long start, int len, int blocksize)
1158 {
1159 journal_t *journal = journal_init_common();
1160 struct buffer_head *bh;
1161 int n;
1162
1163 if (!journal)
1164 return NULL;
1165
1166 /* journal descriptor can store up to n blocks -bzzz */
1167 journal->j_blocksize = blocksize;
1168 journal->j_dev = bdev;
1169 journal->j_fs_dev = fs_dev;
1170 journal->j_blk_offset = start;
1171 journal->j_maxlen = len;
1172 bdevname(journal->j_dev, journal->j_devname);
1173 strreplace(journal->j_devname, '/', '!');
1174 jbd2_stats_proc_init(journal);
1175 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1176 journal->j_wbufsize = n;
1177 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1178 if (!journal->j_wbuf) {
1179 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1180 __func__);
1181 goto out_err;
1182 }
1183
1184 bh = __getblk(journal->j_dev, start, journal->j_blocksize);
1185 if (!bh) {
1186 printk(KERN_ERR
1187 "%s: Cannot get buffer for journal superblock\n",
1188 __func__);
1189 goto out_err;
1190 }
1191 journal->j_sb_buffer = bh;
1192 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1193
1194 return journal;
1195 out_err:
1196 kfree(journal->j_wbuf);
1197 jbd2_stats_proc_exit(journal);
1198 kfree(journal);
1199 return NULL;
1200 }
1201
1202 /**
1203 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1204 * @inode: An inode to create the journal in
1205 *
1206 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1207 * the journal. The inode must exist already, must support bmap() and
1208 * must have all data blocks preallocated.
1209 */
1210 journal_t * jbd2_journal_init_inode (struct inode *inode)
1211 {
1212 struct buffer_head *bh;
1213 journal_t *journal = journal_init_common();
1214 char *p;
1215 int err;
1216 int n;
1217 unsigned long long blocknr;
1218
1219 if (!journal)
1220 return NULL;
1221
1222 journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
1223 journal->j_inode = inode;
1224 bdevname(journal->j_dev, journal->j_devname);
1225 p = strreplace(journal->j_devname, '/', '!');
1226 sprintf(p, "-%lu", journal->j_inode->i_ino);
1227 jbd_debug(1,
1228 "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
1229 journal, inode->i_sb->s_id, inode->i_ino,
1230 (long long) inode->i_size,
1231 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1232
1233 journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
1234 journal->j_blocksize = inode->i_sb->s_blocksize;
1235 jbd2_stats_proc_init(journal);
1236
1237 /* journal descriptor can store up to n blocks -bzzz */
1238 n = journal->j_blocksize / sizeof(journal_block_tag_t);
1239 journal->j_wbufsize = n;
1240 journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
1241 if (!journal->j_wbuf) {
1242 printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
1243 __func__);
1244 goto out_err;
1245 }
1246
1247 err = jbd2_journal_bmap(journal, 0, &blocknr);
1248 /* If that failed, give up */
1249 if (err) {
1250 printk(KERN_ERR "%s: Cannot locate journal superblock\n",
1251 __func__);
1252 goto out_err;
1253 }
1254
1255 bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize);
1256 if (!bh) {
1257 printk(KERN_ERR
1258 "%s: Cannot get buffer for journal superblock\n",
1259 __func__);
1260 goto out_err;
1261 }
1262 journal->j_sb_buffer = bh;
1263 journal->j_superblock = (journal_superblock_t *)bh->b_data;
1264
1265 return journal;
1266 out_err:
1267 kfree(journal->j_wbuf);
1268 jbd2_stats_proc_exit(journal);
1269 kfree(journal);
1270 return NULL;
1271 }
1272
1273 /*
1274 * If the journal init or create aborts, we need to mark the journal
1275 * superblock as being NULL to prevent the journal destroy from writing
1276 * back a bogus superblock.
1277 */
1278 static void journal_fail_superblock (journal_t *journal)
1279 {
1280 struct buffer_head *bh = journal->j_sb_buffer;
1281 brelse(bh);
1282 journal->j_sb_buffer = NULL;
1283 }
1284
1285 /*
1286 * Given a journal_t structure, initialise the various fields for
1287 * startup of a new journaling session. We use this both when creating
1288 * a journal, and after recovering an old journal to reset it for
1289 * subsequent use.
1290 */
1291
1292 static int journal_reset(journal_t *journal)
1293 {
1294 journal_superblock_t *sb = journal->j_superblock;
1295 unsigned long long first, last;
1296
1297 first = be32_to_cpu(sb->s_first);
1298 last = be32_to_cpu(sb->s_maxlen);
1299 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1300 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1301 first, last);
1302 journal_fail_superblock(journal);
1303 return -EINVAL;
1304 }
1305
1306 journal->j_first = first;
1307 journal->j_last = last;
1308
1309 journal->j_head = first;
1310 journal->j_tail = first;
1311 journal->j_free = last - first;
1312
1313 journal->j_tail_sequence = journal->j_transaction_sequence;
1314 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1315 journal->j_commit_request = journal->j_commit_sequence;
1316
1317 journal->j_max_transaction_buffers = journal->j_maxlen / 4;
1318
1319 /*
1320 * As a special case, if the on-disk copy is already marked as needing
1321 * no recovery (s_start == 0), then we can safely defer the superblock
1322 * update until the next commit by setting JBD2_FLUSHED. This avoids
1323 * attempting a write to a potential-readonly device.
1324 */
1325 if (sb->s_start == 0) {
1326 jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
1327 "(start %ld, seq %d, errno %d)\n",
1328 journal->j_tail, journal->j_tail_sequence,
1329 journal->j_errno);
1330 journal->j_flags |= JBD2_FLUSHED;
1331 } else {
1332 /* Lock here to make assertions happy... */
1333 mutex_lock(&journal->j_checkpoint_mutex);
1334 /*
1335 * Update log tail information. We use WRITE_FUA since new
1336 * transaction will start reusing journal space and so we
1337 * must make sure information about current log tail is on
1338 * disk before that.
1339 */
1340 jbd2_journal_update_sb_log_tail(journal,
1341 journal->j_tail_sequence,
1342 journal->j_tail,
1343 WRITE_FUA);
1344 mutex_unlock(&journal->j_checkpoint_mutex);
1345 }
1346 return jbd2_journal_start_thread(journal);
1347 }
1348
1349 static int jbd2_write_superblock(journal_t *journal, int write_flags)
1350 {
1351 struct buffer_head *bh = journal->j_sb_buffer;
1352 journal_superblock_t *sb = journal->j_superblock;
1353 int ret;
1354
1355 trace_jbd2_write_superblock(journal, write_flags);
1356 if (!(journal->j_flags & JBD2_BARRIER))
1357 write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1358 lock_buffer(bh);
1359 if (buffer_write_io_error(bh)) {
1360 /*
1361 * Oh, dear. A previous attempt to write the journal
1362 * superblock failed. This could happen because the
1363 * USB device was yanked out. Or it could happen to
1364 * be a transient write error and maybe the block will
1365 * be remapped. Nothing we can do but to retry the
1366 * write and hope for the best.
1367 */
1368 printk(KERN_ERR "JBD2: previous I/O error detected "
1369 "for journal superblock update for %s.\n",
1370 journal->j_devname);
1371 clear_buffer_write_io_error(bh);
1372 set_buffer_uptodate(bh);
1373 }
1374 jbd2_superblock_csum_set(journal, sb);
1375 get_bh(bh);
1376 bh->b_end_io = end_buffer_write_sync;
1377 ret = submit_bh(REQ_OP_WRITE, write_flags, bh);
1378 wait_on_buffer(bh);
1379 if (buffer_write_io_error(bh)) {
1380 clear_buffer_write_io_error(bh);
1381 set_buffer_uptodate(bh);
1382 ret = -EIO;
1383 }
1384 if (ret) {
1385 printk(KERN_ERR "JBD2: Error %d detected when updating "
1386 "journal superblock for %s.\n", ret,
1387 journal->j_devname);
1388 jbd2_journal_abort(journal, ret);
1389 }
1390
1391 return ret;
1392 }
1393
1394 /**
1395 * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1396 * @journal: The journal to update.
1397 * @tail_tid: TID of the new transaction at the tail of the log
1398 * @tail_block: The first block of the transaction at the tail of the log
1399 * @write_op: With which operation should we write the journal sb
1400 *
1401 * Update a journal's superblock information about log tail and write it to
1402 * disk, waiting for the IO to complete.
1403 */
1404 int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1405 unsigned long tail_block, int write_op)
1406 {
1407 journal_superblock_t *sb = journal->j_superblock;
1408 int ret;
1409
1410 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1411 jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1412 tail_block, tail_tid);
1413
1414 sb->s_sequence = cpu_to_be32(tail_tid);
1415 sb->s_start = cpu_to_be32(tail_block);
1416
1417 ret = jbd2_write_superblock(journal, write_op);
1418 if (ret)
1419 goto out;
1420
1421 /* Log is no longer empty */
1422 write_lock(&journal->j_state_lock);
1423 WARN_ON(!sb->s_sequence);
1424 journal->j_flags &= ~JBD2_FLUSHED;
1425 write_unlock(&journal->j_state_lock);
1426
1427 out:
1428 return ret;
1429 }
1430
1431 /**
1432 * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1433 * @journal: The journal to update.
1434 * @write_op: With which operation should we write the journal sb
1435 *
1436 * Update a journal's dynamic superblock fields to show that journal is empty.
1437 * Write updated superblock to disk waiting for IO to complete.
1438 */
1439 static void jbd2_mark_journal_empty(journal_t *journal, int write_op)
1440 {
1441 journal_superblock_t *sb = journal->j_superblock;
1442
1443 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1444 read_lock(&journal->j_state_lock);
1445 /* Is it already empty? */
1446 if (sb->s_start == 0) {
1447 read_unlock(&journal->j_state_lock);
1448 return;
1449 }
1450 jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
1451 journal->j_tail_sequence);
1452
1453 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1454 sb->s_start = cpu_to_be32(0);
1455 read_unlock(&journal->j_state_lock);
1456
1457 jbd2_write_superblock(journal, write_op);
1458
1459 /* Log is no longer empty */
1460 write_lock(&journal->j_state_lock);
1461 journal->j_flags |= JBD2_FLUSHED;
1462 write_unlock(&journal->j_state_lock);
1463 }
1464
1465
1466 /**
1467 * jbd2_journal_update_sb_errno() - Update error in the journal.
1468 * @journal: The journal to update.
1469 *
1470 * Update a journal's errno. Write updated superblock to disk waiting for IO
1471 * to complete.
1472 */
1473 void jbd2_journal_update_sb_errno(journal_t *journal)
1474 {
1475 journal_superblock_t *sb = journal->j_superblock;
1476
1477 read_lock(&journal->j_state_lock);
1478 jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
1479 journal->j_errno);
1480 sb->s_errno = cpu_to_be32(journal->j_errno);
1481 read_unlock(&journal->j_state_lock);
1482
1483 jbd2_write_superblock(journal, WRITE_FUA);
1484 }
1485 EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
1486
1487 /*
1488 * Read the superblock for a given journal, performing initial
1489 * validation of the format.
1490 */
1491 static int journal_get_superblock(journal_t *journal)
1492 {
1493 struct buffer_head *bh;
1494 journal_superblock_t *sb;
1495 int err = -EIO;
1496
1497 bh = journal->j_sb_buffer;
1498
1499 J_ASSERT(bh != NULL);
1500 if (!buffer_uptodate(bh)) {
1501 ll_rw_block(REQ_OP_READ, 0, 1, &bh);
1502 wait_on_buffer(bh);
1503 if (!buffer_uptodate(bh)) {
1504 printk(KERN_ERR
1505 "JBD2: IO error reading journal superblock\n");
1506 goto out;
1507 }
1508 }
1509
1510 if (buffer_verified(bh))
1511 return 0;
1512
1513 sb = journal->j_superblock;
1514
1515 err = -EINVAL;
1516
1517 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1518 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1519 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1520 goto out;
1521 }
1522
1523 switch(be32_to_cpu(sb->s_header.h_blocktype)) {
1524 case JBD2_SUPERBLOCK_V1:
1525 journal->j_format_version = 1;
1526 break;
1527 case JBD2_SUPERBLOCK_V2:
1528 journal->j_format_version = 2;
1529 break;
1530 default:
1531 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1532 goto out;
1533 }
1534
1535 if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
1536 journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
1537 else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
1538 printk(KERN_WARNING "JBD2: journal file too short\n");
1539 goto out;
1540 }
1541
1542 if (be32_to_cpu(sb->s_first) == 0 ||
1543 be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
1544 printk(KERN_WARNING
1545 "JBD2: Invalid start block of journal: %u\n",
1546 be32_to_cpu(sb->s_first));
1547 goto out;
1548 }
1549
1550 if (jbd2_has_feature_csum2(journal) &&
1551 jbd2_has_feature_csum3(journal)) {
1552 /* Can't have checksum v2 and v3 at the same time! */
1553 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1554 "at the same time!\n");
1555 goto out;
1556 }
1557
1558 if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1559 jbd2_has_feature_checksum(journal)) {
1560 /* Can't have checksum v1 and v2 on at the same time! */
1561 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1562 "at the same time!\n");
1563 goto out;
1564 }
1565
1566 if (!jbd2_verify_csum_type(journal, sb)) {
1567 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1568 goto out;
1569 }
1570
1571 /* Load the checksum driver */
1572 if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1573 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1574 if (IS_ERR(journal->j_chksum_driver)) {
1575 printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1576 err = PTR_ERR(journal->j_chksum_driver);
1577 journal->j_chksum_driver = NULL;
1578 goto out;
1579 }
1580 }
1581
1582 /* Check superblock checksum */
1583 if (!jbd2_superblock_csum_verify(journal, sb)) {
1584 printk(KERN_ERR "JBD2: journal checksum error\n");
1585 err = -EFSBADCRC;
1586 goto out;
1587 }
1588
1589 /* Precompute checksum seed for all metadata */
1590 if (jbd2_journal_has_csum_v2or3(journal))
1591 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1592 sizeof(sb->s_uuid));
1593
1594 set_buffer_verified(bh);
1595
1596 return 0;
1597
1598 out:
1599 journal_fail_superblock(journal);
1600 return err;
1601 }
1602
1603 /*
1604 * Load the on-disk journal superblock and read the key fields into the
1605 * journal_t.
1606 */
1607
1608 static int load_superblock(journal_t *journal)
1609 {
1610 int err;
1611 journal_superblock_t *sb;
1612
1613 err = journal_get_superblock(journal);
1614 if (err)
1615 return err;
1616
1617 sb = journal->j_superblock;
1618
1619 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1620 journal->j_tail = be32_to_cpu(sb->s_start);
1621 journal->j_first = be32_to_cpu(sb->s_first);
1622 journal->j_last = be32_to_cpu(sb->s_maxlen);
1623 journal->j_errno = be32_to_cpu(sb->s_errno);
1624
1625 return 0;
1626 }
1627
1628
1629 /**
1630 * int jbd2_journal_load() - Read journal from disk.
1631 * @journal: Journal to act on.
1632 *
1633 * Given a journal_t structure which tells us which disk blocks contain
1634 * a journal, read the journal from disk to initialise the in-memory
1635 * structures.
1636 */
1637 int jbd2_journal_load(journal_t *journal)
1638 {
1639 int err;
1640 journal_superblock_t *sb;
1641
1642 err = load_superblock(journal);
1643 if (err)
1644 return err;
1645
1646 sb = journal->j_superblock;
1647 /* If this is a V2 superblock, then we have to check the
1648 * features flags on it. */
1649
1650 if (journal->j_format_version >= 2) {
1651 if ((sb->s_feature_ro_compat &
1652 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1653 (sb->s_feature_incompat &
1654 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1655 printk(KERN_WARNING
1656 "JBD2: Unrecognised features on journal\n");
1657 return -EINVAL;
1658 }
1659 }
1660
1661 /*
1662 * Create a slab for this blocksize
1663 */
1664 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
1665 if (err)
1666 return err;
1667
1668 /* Let the recovery code check whether it needs to recover any
1669 * data from the journal. */
1670 if (jbd2_journal_recover(journal))
1671 goto recovery_error;
1672
1673 if (journal->j_failed_commit) {
1674 printk(KERN_ERR "JBD2: journal transaction %u on %s "
1675 "is corrupt.\n", journal->j_failed_commit,
1676 journal->j_devname);
1677 return -EFSCORRUPTED;
1678 }
1679
1680 /* OK, we've finished with the dynamic journal bits:
1681 * reinitialise the dynamic contents of the superblock in memory
1682 * and reset them on disk. */
1683 if (journal_reset(journal))
1684 goto recovery_error;
1685
1686 journal->j_flags &= ~JBD2_ABORT;
1687 journal->j_flags |= JBD2_LOADED;
1688 return 0;
1689
1690 recovery_error:
1691 printk(KERN_WARNING "JBD2: recovery failed\n");
1692 return -EIO;
1693 }
1694
1695 /**
1696 * void jbd2_journal_destroy() - Release a journal_t structure.
1697 * @journal: Journal to act on.
1698 *
1699 * Release a journal_t structure once it is no longer in use by the
1700 * journaled object.
1701 * Return <0 if we couldn't clean up the journal.
1702 */
1703 int jbd2_journal_destroy(journal_t *journal)
1704 {
1705 int err = 0;
1706
1707 /* Wait for the commit thread to wake up and die. */
1708 journal_kill_thread(journal);
1709
1710 /* Force a final log commit */
1711 if (journal->j_running_transaction)
1712 jbd2_journal_commit_transaction(journal);
1713
1714 /* Force any old transactions to disk */
1715
1716 /* Totally anal locking here... */
1717 spin_lock(&journal->j_list_lock);
1718 while (journal->j_checkpoint_transactions != NULL) {
1719 spin_unlock(&journal->j_list_lock);
1720 mutex_lock(&journal->j_checkpoint_mutex);
1721 err = jbd2_log_do_checkpoint(journal);
1722 mutex_unlock(&journal->j_checkpoint_mutex);
1723 /*
1724 * If checkpointing failed, just free the buffers to avoid
1725 * looping forever
1726 */
1727 if (err) {
1728 jbd2_journal_destroy_checkpoint(journal);
1729 spin_lock(&journal->j_list_lock);
1730 break;
1731 }
1732 spin_lock(&journal->j_list_lock);
1733 }
1734
1735 J_ASSERT(journal->j_running_transaction == NULL);
1736 J_ASSERT(journal->j_committing_transaction == NULL);
1737 J_ASSERT(journal->j_checkpoint_transactions == NULL);
1738 spin_unlock(&journal->j_list_lock);
1739
1740 if (journal->j_sb_buffer) {
1741 if (!is_journal_aborted(journal)) {
1742 mutex_lock(&journal->j_checkpoint_mutex);
1743
1744 write_lock(&journal->j_state_lock);
1745 journal->j_tail_sequence =
1746 ++journal->j_transaction_sequence;
1747 write_unlock(&journal->j_state_lock);
1748
1749 jbd2_mark_journal_empty(journal, WRITE_FLUSH_FUA);
1750 mutex_unlock(&journal->j_checkpoint_mutex);
1751 } else
1752 err = -EIO;
1753 brelse(journal->j_sb_buffer);
1754 }
1755
1756 if (journal->j_proc_entry)
1757 jbd2_stats_proc_exit(journal);
1758 iput(journal->j_inode);
1759 if (journal->j_revoke)
1760 jbd2_journal_destroy_revoke(journal);
1761 if (journal->j_chksum_driver)
1762 crypto_free_shash(journal->j_chksum_driver);
1763 kfree(journal->j_wbuf);
1764 kfree(journal);
1765
1766 return err;
1767 }
1768
1769
1770 /**
1771 *int jbd2_journal_check_used_features () - Check if features specified are used.
1772 * @journal: Journal to check.
1773 * @compat: bitmask of compatible features
1774 * @ro: bitmask of features that force read-only mount
1775 * @incompat: bitmask of incompatible features
1776 *
1777 * Check whether the journal uses all of a given set of
1778 * features. Return true (non-zero) if it does.
1779 **/
1780
1781 int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
1782 unsigned long ro, unsigned long incompat)
1783 {
1784 journal_superblock_t *sb;
1785
1786 if (!compat && !ro && !incompat)
1787 return 1;
1788 /* Load journal superblock if it is not loaded yet. */
1789 if (journal->j_format_version == 0 &&
1790 journal_get_superblock(journal) != 0)
1791 return 0;
1792 if (journal->j_format_version == 1)
1793 return 0;
1794
1795 sb = journal->j_superblock;
1796
1797 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
1798 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
1799 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
1800 return 1;
1801
1802 return 0;
1803 }
1804
1805 /**
1806 * int jbd2_journal_check_available_features() - Check feature set in journalling layer
1807 * @journal: Journal to check.
1808 * @compat: bitmask of compatible features
1809 * @ro: bitmask of features that force read-only mount
1810 * @incompat: bitmask of incompatible features
1811 *
1812 * Check whether the journaling code supports the use of
1813 * all of a given set of features on this journal. Return true
1814 * (non-zero) if it can. */
1815
1816 int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
1817 unsigned long ro, unsigned long incompat)
1818 {
1819 if (!compat && !ro && !incompat)
1820 return 1;
1821
1822 /* We can support any known requested features iff the
1823 * superblock is in version 2. Otherwise we fail to support any
1824 * extended sb features. */
1825
1826 if (journal->j_format_version != 2)
1827 return 0;
1828
1829 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
1830 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
1831 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
1832 return 1;
1833
1834 return 0;
1835 }
1836
1837 /**
1838 * int jbd2_journal_set_features () - Mark a given journal feature in the superblock
1839 * @journal: Journal to act on.
1840 * @compat: bitmask of compatible features
1841 * @ro: bitmask of features that force read-only mount
1842 * @incompat: bitmask of incompatible features
1843 *
1844 * Mark a given journal feature as present on the
1845 * superblock. Returns true if the requested features could be set.
1846 *
1847 */
1848
1849 int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
1850 unsigned long ro, unsigned long incompat)
1851 {
1852 #define INCOMPAT_FEATURE_ON(f) \
1853 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
1854 #define COMPAT_FEATURE_ON(f) \
1855 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
1856 journal_superblock_t *sb;
1857
1858 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
1859 return 1;
1860
1861 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
1862 return 0;
1863
1864 /* If enabling v2 checksums, turn on v3 instead */
1865 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
1866 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
1867 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
1868 }
1869
1870 /* Asking for checksumming v3 and v1? Only give them v3. */
1871 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
1872 compat & JBD2_FEATURE_COMPAT_CHECKSUM)
1873 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
1874
1875 jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
1876 compat, ro, incompat);
1877
1878 sb = journal->j_superblock;
1879
1880 /* If enabling v3 checksums, update superblock */
1881 if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
1882 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
1883 sb->s_feature_compat &=
1884 ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
1885
1886 /* Load the checksum driver */
1887 if (journal->j_chksum_driver == NULL) {
1888 journal->j_chksum_driver = crypto_alloc_shash("crc32c",
1889 0, 0);
1890 if (IS_ERR(journal->j_chksum_driver)) {
1891 printk(KERN_ERR "JBD2: Cannot load crc32c "
1892 "driver.\n");
1893 journal->j_chksum_driver = NULL;
1894 return 0;
1895 }
1896
1897 /* Precompute checksum seed for all metadata */
1898 journal->j_csum_seed = jbd2_chksum(journal, ~0,
1899 sb->s_uuid,
1900 sizeof(sb->s_uuid));
1901 }
1902 }
1903
1904 /* If enabling v1 checksums, downgrade superblock */
1905 if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
1906 sb->s_feature_incompat &=
1907 ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
1908 JBD2_FEATURE_INCOMPAT_CSUM_V3);
1909
1910 sb->s_feature_compat |= cpu_to_be32(compat);
1911 sb->s_feature_ro_compat |= cpu_to_be32(ro);
1912 sb->s_feature_incompat |= cpu_to_be32(incompat);
1913
1914 return 1;
1915 #undef COMPAT_FEATURE_ON
1916 #undef INCOMPAT_FEATURE_ON
1917 }
1918
1919 /*
1920 * jbd2_journal_clear_features () - Clear a given journal feature in the
1921 * superblock
1922 * @journal: Journal to act on.
1923 * @compat: bitmask of compatible features
1924 * @ro: bitmask of features that force read-only mount
1925 * @incompat: bitmask of incompatible features
1926 *
1927 * Clear a given journal feature as present on the
1928 * superblock.
1929 */
1930 void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
1931 unsigned long ro, unsigned long incompat)
1932 {
1933 journal_superblock_t *sb;
1934
1935 jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
1936 compat, ro, incompat);
1937
1938 sb = journal->j_superblock;
1939
1940 sb->s_feature_compat &= ~cpu_to_be32(compat);
1941 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
1942 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
1943 }
1944 EXPORT_SYMBOL(jbd2_journal_clear_features);
1945
1946 /**
1947 * int jbd2_journal_flush () - Flush journal
1948 * @journal: Journal to act on.
1949 *
1950 * Flush all data for a given journal to disk and empty the journal.
1951 * Filesystems can use this when remounting readonly to ensure that
1952 * recovery does not need to happen on remount.
1953 */
1954
1955 int jbd2_journal_flush(journal_t *journal)
1956 {
1957 int err = 0;
1958 transaction_t *transaction = NULL;
1959
1960 write_lock(&journal->j_state_lock);
1961
1962 /* Force everything buffered to the log... */
1963 if (journal->j_running_transaction) {
1964 transaction = journal->j_running_transaction;
1965 __jbd2_log_start_commit(journal, transaction->t_tid);
1966 } else if (journal->j_committing_transaction)
1967 transaction = journal->j_committing_transaction;
1968
1969 /* Wait for the log commit to complete... */
1970 if (transaction) {
1971 tid_t tid = transaction->t_tid;
1972
1973 write_unlock(&journal->j_state_lock);
1974 jbd2_log_wait_commit(journal, tid);
1975 } else {
1976 write_unlock(&journal->j_state_lock);
1977 }
1978
1979 /* ...and flush everything in the log out to disk. */
1980 spin_lock(&journal->j_list_lock);
1981 while (!err && journal->j_checkpoint_transactions != NULL) {
1982 spin_unlock(&journal->j_list_lock);
1983 mutex_lock(&journal->j_checkpoint_mutex);
1984 err = jbd2_log_do_checkpoint(journal);
1985 mutex_unlock(&journal->j_checkpoint_mutex);
1986 spin_lock(&journal->j_list_lock);
1987 }
1988 spin_unlock(&journal->j_list_lock);
1989
1990 if (is_journal_aborted(journal))
1991 return -EIO;
1992
1993 mutex_lock(&journal->j_checkpoint_mutex);
1994 if (!err) {
1995 err = jbd2_cleanup_journal_tail(journal);
1996 if (err < 0) {
1997 mutex_unlock(&journal->j_checkpoint_mutex);
1998 goto out;
1999 }
2000 err = 0;
2001 }
2002
2003 /* Finally, mark the journal as really needing no recovery.
2004 * This sets s_start==0 in the underlying superblock, which is
2005 * the magic code for a fully-recovered superblock. Any future
2006 * commits of data to the journal will restore the current
2007 * s_start value. */
2008 jbd2_mark_journal_empty(journal, WRITE_FUA);
2009 mutex_unlock(&journal->j_checkpoint_mutex);
2010 write_lock(&journal->j_state_lock);
2011 J_ASSERT(!journal->j_running_transaction);
2012 J_ASSERT(!journal->j_committing_transaction);
2013 J_ASSERT(!journal->j_checkpoint_transactions);
2014 J_ASSERT(journal->j_head == journal->j_tail);
2015 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2016 write_unlock(&journal->j_state_lock);
2017 out:
2018 return err;
2019 }
2020
2021 /**
2022 * int jbd2_journal_wipe() - Wipe journal contents
2023 * @journal: Journal to act on.
2024 * @write: flag (see below)
2025 *
2026 * Wipe out all of the contents of a journal, safely. This will produce
2027 * a warning if the journal contains any valid recovery information.
2028 * Must be called between journal_init_*() and jbd2_journal_load().
2029 *
2030 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2031 * we merely suppress recovery.
2032 */
2033
2034 int jbd2_journal_wipe(journal_t *journal, int write)
2035 {
2036 int err = 0;
2037
2038 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2039
2040 err = load_superblock(journal);
2041 if (err)
2042 return err;
2043
2044 if (!journal->j_tail)
2045 goto no_recovery;
2046
2047 printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2048 write ? "Clearing" : "Ignoring");
2049
2050 err = jbd2_journal_skip_recovery(journal);
2051 if (write) {
2052 /* Lock to make assertions happy... */
2053 mutex_lock(&journal->j_checkpoint_mutex);
2054 jbd2_mark_journal_empty(journal, WRITE_FUA);
2055 mutex_unlock(&journal->j_checkpoint_mutex);
2056 }
2057
2058 no_recovery:
2059 return err;
2060 }
2061
2062 /*
2063 * Journal abort has very specific semantics, which we describe
2064 * for journal abort.
2065 *
2066 * Two internal functions, which provide abort to the jbd layer
2067 * itself are here.
2068 */
2069
2070 /*
2071 * Quick version for internal journal use (doesn't lock the journal).
2072 * Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
2073 * and don't attempt to make any other journal updates.
2074 */
2075 void __jbd2_journal_abort_hard(journal_t *journal)
2076 {
2077 transaction_t *transaction;
2078
2079 if (journal->j_flags & JBD2_ABORT)
2080 return;
2081
2082 printk(KERN_ERR "Aborting journal on device %s.\n",
2083 journal->j_devname);
2084
2085 write_lock(&journal->j_state_lock);
2086 journal->j_flags |= JBD2_ABORT;
2087 transaction = journal->j_running_transaction;
2088 if (transaction)
2089 __jbd2_log_start_commit(journal, transaction->t_tid);
2090 write_unlock(&journal->j_state_lock);
2091 }
2092
2093 /* Soft abort: record the abort error status in the journal superblock,
2094 * but don't do any other IO. */
2095 static void __journal_abort_soft (journal_t *journal, int errno)
2096 {
2097 if (journal->j_flags & JBD2_ABORT)
2098 return;
2099
2100 if (!journal->j_errno)
2101 journal->j_errno = errno;
2102
2103 __jbd2_journal_abort_hard(journal);
2104
2105 if (errno) {
2106 jbd2_journal_update_sb_errno(journal);
2107 write_lock(&journal->j_state_lock);
2108 journal->j_flags |= JBD2_REC_ERR;
2109 write_unlock(&journal->j_state_lock);
2110 }
2111 }
2112
2113 /**
2114 * void jbd2_journal_abort () - Shutdown the journal immediately.
2115 * @journal: the journal to shutdown.
2116 * @errno: an error number to record in the journal indicating
2117 * the reason for the shutdown.
2118 *
2119 * Perform a complete, immediate shutdown of the ENTIRE
2120 * journal (not of a single transaction). This operation cannot be
2121 * undone without closing and reopening the journal.
2122 *
2123 * The jbd2_journal_abort function is intended to support higher level error
2124 * recovery mechanisms such as the ext2/ext3 remount-readonly error
2125 * mode.
2126 *
2127 * Journal abort has very specific semantics. Any existing dirty,
2128 * unjournaled buffers in the main filesystem will still be written to
2129 * disk by bdflush, but the journaling mechanism will be suspended
2130 * immediately and no further transaction commits will be honoured.
2131 *
2132 * Any dirty, journaled buffers will be written back to disk without
2133 * hitting the journal. Atomicity cannot be guaranteed on an aborted
2134 * filesystem, but we _do_ attempt to leave as much data as possible
2135 * behind for fsck to use for cleanup.
2136 *
2137 * Any attempt to get a new transaction handle on a journal which is in
2138 * ABORT state will just result in an -EROFS error return. A
2139 * jbd2_journal_stop on an existing handle will return -EIO if we have
2140 * entered abort state during the update.
2141 *
2142 * Recursive transactions are not disturbed by journal abort until the
2143 * final jbd2_journal_stop, which will receive the -EIO error.
2144 *
2145 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2146 * which will be recorded (if possible) in the journal superblock. This
2147 * allows a client to record failure conditions in the middle of a
2148 * transaction without having to complete the transaction to record the
2149 * failure to disk. ext3_error, for example, now uses this
2150 * functionality.
2151 *
2152 * Errors which originate from within the journaling layer will NOT
2153 * supply an errno; a null errno implies that absolutely no further
2154 * writes are done to the journal (unless there are any already in
2155 * progress).
2156 *
2157 */
2158
2159 void jbd2_journal_abort(journal_t *journal, int errno)
2160 {
2161 __journal_abort_soft(journal, errno);
2162 }
2163
2164 /**
2165 * int jbd2_journal_errno () - returns the journal's error state.
2166 * @journal: journal to examine.
2167 *
2168 * This is the errno number set with jbd2_journal_abort(), the last
2169 * time the journal was mounted - if the journal was stopped
2170 * without calling abort this will be 0.
2171 *
2172 * If the journal has been aborted on this mount time -EROFS will
2173 * be returned.
2174 */
2175 int jbd2_journal_errno(journal_t *journal)
2176 {
2177 int err;
2178
2179 read_lock(&journal->j_state_lock);
2180 if (journal->j_flags & JBD2_ABORT)
2181 err = -EROFS;
2182 else
2183 err = journal->j_errno;
2184 read_unlock(&journal->j_state_lock);
2185 return err;
2186 }
2187
2188 /**
2189 * int jbd2_journal_clear_err () - clears the journal's error state
2190 * @journal: journal to act on.
2191 *
2192 * An error must be cleared or acked to take a FS out of readonly
2193 * mode.
2194 */
2195 int jbd2_journal_clear_err(journal_t *journal)
2196 {
2197 int err = 0;
2198
2199 write_lock(&journal->j_state_lock);
2200 if (journal->j_flags & JBD2_ABORT)
2201 err = -EROFS;
2202 else
2203 journal->j_errno = 0;
2204 write_unlock(&journal->j_state_lock);
2205 return err;
2206 }
2207
2208 /**
2209 * void jbd2_journal_ack_err() - Ack journal err.
2210 * @journal: journal to act on.
2211 *
2212 * An error must be cleared or acked to take a FS out of readonly
2213 * mode.
2214 */
2215 void jbd2_journal_ack_err(journal_t *journal)
2216 {
2217 write_lock(&journal->j_state_lock);
2218 if (journal->j_errno)
2219 journal->j_flags |= JBD2_ACK_ERR;
2220 write_unlock(&journal->j_state_lock);
2221 }
2222
2223 int jbd2_journal_blocks_per_page(struct inode *inode)
2224 {
2225 return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2226 }
2227
2228 /*
2229 * helper functions to deal with 32 or 64bit block numbers.
2230 */
2231 size_t journal_tag_bytes(journal_t *journal)
2232 {
2233 size_t sz;
2234
2235 if (jbd2_has_feature_csum3(journal))
2236 return sizeof(journal_block_tag3_t);
2237
2238 sz = sizeof(journal_block_tag_t);
2239
2240 if (jbd2_has_feature_csum2(journal))
2241 sz += sizeof(__u16);
2242
2243 if (jbd2_has_feature_64bit(journal))
2244 return sz;
2245 else
2246 return sz - sizeof(__u32);
2247 }
2248
2249 /*
2250 * JBD memory management
2251 *
2252 * These functions are used to allocate block-sized chunks of memory
2253 * used for making copies of buffer_head data. Very often it will be
2254 * page-sized chunks of data, but sometimes it will be in
2255 * sub-page-size chunks. (For example, 16k pages on Power systems
2256 * with a 4k block file system.) For blocks smaller than a page, we
2257 * use a SLAB allocator. There are slab caches for each block size,
2258 * which are allocated at mount time, if necessary, and we only free
2259 * (all of) the slab caches when/if the jbd2 module is unloaded. For
2260 * this reason we don't need to a mutex to protect access to
2261 * jbd2_slab[] allocating or releasing memory; only in
2262 * jbd2_journal_create_slab().
2263 */
2264 #define JBD2_MAX_SLABS 8
2265 static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2266
2267 static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2268 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2269 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2270 };
2271
2272
2273 static void jbd2_journal_destroy_slabs(void)
2274 {
2275 int i;
2276
2277 for (i = 0; i < JBD2_MAX_SLABS; i++) {
2278 if (jbd2_slab[i])
2279 kmem_cache_destroy(jbd2_slab[i]);
2280 jbd2_slab[i] = NULL;
2281 }
2282 }
2283
2284 static int jbd2_journal_create_slab(size_t size)
2285 {
2286 static DEFINE_MUTEX(jbd2_slab_create_mutex);
2287 int i = order_base_2(size) - 10;
2288 size_t slab_size;
2289
2290 if (size == PAGE_SIZE)
2291 return 0;
2292
2293 if (i >= JBD2_MAX_SLABS)
2294 return -EINVAL;
2295
2296 if (unlikely(i < 0))
2297 i = 0;
2298 mutex_lock(&jbd2_slab_create_mutex);
2299 if (jbd2_slab[i]) {
2300 mutex_unlock(&jbd2_slab_create_mutex);
2301 return 0; /* Already created */
2302 }
2303
2304 slab_size = 1 << (i+10);
2305 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2306 slab_size, 0, NULL);
2307 mutex_unlock(&jbd2_slab_create_mutex);
2308 if (!jbd2_slab[i]) {
2309 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2310 return -ENOMEM;
2311 }
2312 return 0;
2313 }
2314
2315 static struct kmem_cache *get_slab(size_t size)
2316 {
2317 int i = order_base_2(size) - 10;
2318
2319 BUG_ON(i >= JBD2_MAX_SLABS);
2320 if (unlikely(i < 0))
2321 i = 0;
2322 BUG_ON(jbd2_slab[i] == NULL);
2323 return jbd2_slab[i];
2324 }
2325
2326 void *jbd2_alloc(size_t size, gfp_t flags)
2327 {
2328 void *ptr;
2329
2330 BUG_ON(size & (size-1)); /* Must be a power of 2 */
2331
2332 if (size < PAGE_SIZE)
2333 ptr = kmem_cache_alloc(get_slab(size), flags);
2334 else
2335 ptr = (void *)__get_free_pages(flags, get_order(size));
2336
2337 /* Check alignment; SLUB has gotten this wrong in the past,
2338 * and this can lead to user data corruption! */
2339 BUG_ON(((unsigned long) ptr) & (size-1));
2340
2341 return ptr;
2342 }
2343
2344 void jbd2_free(void *ptr, size_t size)
2345 {
2346 if (size < PAGE_SIZE)
2347 kmem_cache_free(get_slab(size), ptr);
2348 else
2349 free_pages((unsigned long)ptr, get_order(size));
2350 };
2351
2352 /*
2353 * Journal_head storage management
2354 */
2355 static struct kmem_cache *jbd2_journal_head_cache;
2356 #ifdef CONFIG_JBD2_DEBUG
2357 static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2358 #endif
2359
2360 static int jbd2_journal_init_journal_head_cache(void)
2361 {
2362 int retval;
2363
2364 J_ASSERT(jbd2_journal_head_cache == NULL);
2365 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2366 sizeof(struct journal_head),
2367 0, /* offset */
2368 SLAB_TEMPORARY | SLAB_DESTROY_BY_RCU,
2369 NULL); /* ctor */
2370 retval = 0;
2371 if (!jbd2_journal_head_cache) {
2372 retval = -ENOMEM;
2373 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2374 }
2375 return retval;
2376 }
2377
2378 static void jbd2_journal_destroy_journal_head_cache(void)
2379 {
2380 if (jbd2_journal_head_cache) {
2381 kmem_cache_destroy(jbd2_journal_head_cache);
2382 jbd2_journal_head_cache = NULL;
2383 }
2384 }
2385
2386 /*
2387 * journal_head splicing and dicing
2388 */
2389 static struct journal_head *journal_alloc_journal_head(void)
2390 {
2391 struct journal_head *ret;
2392
2393 #ifdef CONFIG_JBD2_DEBUG
2394 atomic_inc(&nr_journal_heads);
2395 #endif
2396 ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2397 if (!ret) {
2398 jbd_debug(1, "out of memory for journal_head\n");
2399 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2400 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2401 GFP_NOFS | __GFP_NOFAIL);
2402 }
2403 return ret;
2404 }
2405
2406 static void journal_free_journal_head(struct journal_head *jh)
2407 {
2408 #ifdef CONFIG_JBD2_DEBUG
2409 atomic_dec(&nr_journal_heads);
2410 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2411 #endif
2412 kmem_cache_free(jbd2_journal_head_cache, jh);
2413 }
2414
2415 /*
2416 * A journal_head is attached to a buffer_head whenever JBD has an
2417 * interest in the buffer.
2418 *
2419 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2420 * is set. This bit is tested in core kernel code where we need to take
2421 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2422 * there.
2423 *
2424 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2425 *
2426 * When a buffer has its BH_JBD bit set it is immune from being released by
2427 * core kernel code, mainly via ->b_count.
2428 *
2429 * A journal_head is detached from its buffer_head when the journal_head's
2430 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2431 * transaction (b_cp_transaction) hold their references to b_jcount.
2432 *
2433 * Various places in the kernel want to attach a journal_head to a buffer_head
2434 * _before_ attaching the journal_head to a transaction. To protect the
2435 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2436 * journal_head's b_jcount refcount by one. The caller must call
2437 * jbd2_journal_put_journal_head() to undo this.
2438 *
2439 * So the typical usage would be:
2440 *
2441 * (Attach a journal_head if needed. Increments b_jcount)
2442 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2443 * ...
2444 * (Get another reference for transaction)
2445 * jbd2_journal_grab_journal_head(bh);
2446 * jh->b_transaction = xxx;
2447 * (Put original reference)
2448 * jbd2_journal_put_journal_head(jh);
2449 */
2450
2451 /*
2452 * Give a buffer_head a journal_head.
2453 *
2454 * May sleep.
2455 */
2456 struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2457 {
2458 struct journal_head *jh;
2459 struct journal_head *new_jh = NULL;
2460
2461 repeat:
2462 if (!buffer_jbd(bh))
2463 new_jh = journal_alloc_journal_head();
2464
2465 jbd_lock_bh_journal_head(bh);
2466 if (buffer_jbd(bh)) {
2467 jh = bh2jh(bh);
2468 } else {
2469 J_ASSERT_BH(bh,
2470 (atomic_read(&bh->b_count) > 0) ||
2471 (bh->b_page && bh->b_page->mapping));
2472
2473 if (!new_jh) {
2474 jbd_unlock_bh_journal_head(bh);
2475 goto repeat;
2476 }
2477
2478 jh = new_jh;
2479 new_jh = NULL; /* We consumed it */
2480 set_buffer_jbd(bh);
2481 bh->b_private = jh;
2482 jh->b_bh = bh;
2483 get_bh(bh);
2484 BUFFER_TRACE(bh, "added journal_head");
2485 }
2486 jh->b_jcount++;
2487 jbd_unlock_bh_journal_head(bh);
2488 if (new_jh)
2489 journal_free_journal_head(new_jh);
2490 return bh->b_private;
2491 }
2492
2493 /*
2494 * Grab a ref against this buffer_head's journal_head. If it ended up not
2495 * having a journal_head, return NULL
2496 */
2497 struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2498 {
2499 struct journal_head *jh = NULL;
2500
2501 jbd_lock_bh_journal_head(bh);
2502 if (buffer_jbd(bh)) {
2503 jh = bh2jh(bh);
2504 jh->b_jcount++;
2505 }
2506 jbd_unlock_bh_journal_head(bh);
2507 return jh;
2508 }
2509
2510 static void __journal_remove_journal_head(struct buffer_head *bh)
2511 {
2512 struct journal_head *jh = bh2jh(bh);
2513
2514 J_ASSERT_JH(jh, jh->b_jcount >= 0);
2515 J_ASSERT_JH(jh, jh->b_transaction == NULL);
2516 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2517 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2518 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2519 J_ASSERT_BH(bh, buffer_jbd(bh));
2520 J_ASSERT_BH(bh, jh2bh(jh) == bh);
2521 BUFFER_TRACE(bh, "remove journal_head");
2522 if (jh->b_frozen_data) {
2523 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2524 jbd2_free(jh->b_frozen_data, bh->b_size);
2525 }
2526 if (jh->b_committed_data) {
2527 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2528 jbd2_free(jh->b_committed_data, bh->b_size);
2529 }
2530 bh->b_private = NULL;
2531 jh->b_bh = NULL; /* debug, really */
2532 clear_buffer_jbd(bh);
2533 journal_free_journal_head(jh);
2534 }
2535
2536 /*
2537 * Drop a reference on the passed journal_head. If it fell to zero then
2538 * release the journal_head from the buffer_head.
2539 */
2540 void jbd2_journal_put_journal_head(struct journal_head *jh)
2541 {
2542 struct buffer_head *bh = jh2bh(jh);
2543
2544 jbd_lock_bh_journal_head(bh);
2545 J_ASSERT_JH(jh, jh->b_jcount > 0);
2546 --jh->b_jcount;
2547 if (!jh->b_jcount) {
2548 __journal_remove_journal_head(bh);
2549 jbd_unlock_bh_journal_head(bh);
2550 __brelse(bh);
2551 } else
2552 jbd_unlock_bh_journal_head(bh);
2553 }
2554
2555 /*
2556 * Initialize jbd inode head
2557 */
2558 void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
2559 {
2560 jinode->i_transaction = NULL;
2561 jinode->i_next_transaction = NULL;
2562 jinode->i_vfs_inode = inode;
2563 jinode->i_flags = 0;
2564 INIT_LIST_HEAD(&jinode->i_list);
2565 }
2566
2567 /*
2568 * Function to be called before we start removing inode from memory (i.e.,
2569 * clear_inode() is a fine place to be called from). It removes inode from
2570 * transaction's lists.
2571 */
2572 void jbd2_journal_release_jbd_inode(journal_t *journal,
2573 struct jbd2_inode *jinode)
2574 {
2575 if (!journal)
2576 return;
2577 restart:
2578 spin_lock(&journal->j_list_lock);
2579 /* Is commit writing out inode - we have to wait */
2580 if (jinode->i_flags & JI_COMMIT_RUNNING) {
2581 wait_queue_head_t *wq;
2582 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
2583 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
2584 prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
2585 spin_unlock(&journal->j_list_lock);
2586 schedule();
2587 finish_wait(wq, &wait.wait);
2588 goto restart;
2589 }
2590
2591 if (jinode->i_transaction) {
2592 list_del(&jinode->i_list);
2593 jinode->i_transaction = NULL;
2594 }
2595 spin_unlock(&journal->j_list_lock);
2596 }
2597
2598
2599 #ifdef CONFIG_PROC_FS
2600
2601 #define JBD2_STATS_PROC_NAME "fs/jbd2"
2602
2603 static void __init jbd2_create_jbd_stats_proc_entry(void)
2604 {
2605 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
2606 }
2607
2608 static void __exit jbd2_remove_jbd_stats_proc_entry(void)
2609 {
2610 if (proc_jbd2_stats)
2611 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
2612 }
2613
2614 #else
2615
2616 #define jbd2_create_jbd_stats_proc_entry() do {} while (0)
2617 #define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
2618
2619 #endif
2620
2621 struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
2622
2623 static int __init jbd2_journal_init_handle_cache(void)
2624 {
2625 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
2626 if (jbd2_handle_cache == NULL) {
2627 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
2628 return -ENOMEM;
2629 }
2630 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
2631 if (jbd2_inode_cache == NULL) {
2632 printk(KERN_EMERG "JBD2: failed to create inode cache\n");
2633 kmem_cache_destroy(jbd2_handle_cache);
2634 return -ENOMEM;
2635 }
2636 return 0;
2637 }
2638
2639 static void jbd2_journal_destroy_handle_cache(void)
2640 {
2641 if (jbd2_handle_cache)
2642 kmem_cache_destroy(jbd2_handle_cache);
2643 if (jbd2_inode_cache)
2644 kmem_cache_destroy(jbd2_inode_cache);
2645
2646 }
2647
2648 /*
2649 * Module startup and shutdown
2650 */
2651
2652 static int __init journal_init_caches(void)
2653 {
2654 int ret;
2655
2656 ret = jbd2_journal_init_revoke_caches();
2657 if (ret == 0)
2658 ret = jbd2_journal_init_journal_head_cache();
2659 if (ret == 0)
2660 ret = jbd2_journal_init_handle_cache();
2661 if (ret == 0)
2662 ret = jbd2_journal_init_transaction_cache();
2663 return ret;
2664 }
2665
2666 static void jbd2_journal_destroy_caches(void)
2667 {
2668 jbd2_journal_destroy_revoke_caches();
2669 jbd2_journal_destroy_journal_head_cache();
2670 jbd2_journal_destroy_handle_cache();
2671 jbd2_journal_destroy_transaction_cache();
2672 jbd2_journal_destroy_slabs();
2673 }
2674
2675 static int __init journal_init(void)
2676 {
2677 int ret;
2678
2679 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
2680
2681 ret = journal_init_caches();
2682 if (ret == 0) {
2683 jbd2_create_jbd_stats_proc_entry();
2684 } else {
2685 jbd2_journal_destroy_caches();
2686 }
2687 return ret;
2688 }
2689
2690 static void __exit journal_exit(void)
2691 {
2692 #ifdef CONFIG_JBD2_DEBUG
2693 int n = atomic_read(&nr_journal_heads);
2694 if (n)
2695 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
2696 #endif
2697 jbd2_remove_jbd_stats_proc_entry();
2698 jbd2_journal_destroy_caches();
2699 }
2700
2701 MODULE_LICENSE("GPL");
2702 module_init(journal_init);
2703 module_exit(journal_exit);
2704