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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 <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
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/journal.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Generic filesystem journal-writing code; part of the ext2fs
10 * journaling system.
11 *
12 * This file manages journals: areas of disk reserved for logging
13 * transactional updates. This includes the kernel journaling thread
14 * which is responsible for scheduling updates to the log.
15 *
16 * We do not actually manage the physical storage of the journal in this
17 * file: that is left to a per-journal policy function, which allows us
18 * to store the journal within a filesystem-specified area for ext2
19 * journaling (ext2 can use a reserved inode for storing the log).
20 */
21
22#include <linux/module.h>
23#include <linux/time.h>
24#include <linux/fs.h>
25#include <linux/jbd2.h>
26#include <linux/errno.h>
27#include <linux/slab.h>
28#include <linux/init.h>
29#include <linux/mm.h>
30#include <linux/freezer.h>
31#include <linux/pagemap.h>
32#include <linux/kthread.h>
33#include <linux/poison.h>
34#include <linux/proc_fs.h>
35#include <linux/seq_file.h>
36#include <linux/math64.h>
37#include <linux/hash.h>
38#include <linux/log2.h>
39#include <linux/vmalloc.h>
40#include <linux/backing-dev.h>
41#include <linux/bitops.h>
42#include <linux/ratelimit.h>
43#include <linux/sched/mm.h>
44
45#define CREATE_TRACE_POINTS
46#include <trace/events/jbd2.h>
47
48#include <linux/uaccess.h>
49#include <asm/page.h>
50
51#ifdef CONFIG_JBD2_DEBUG
52static ushort jbd2_journal_enable_debug __read_mostly;
53
54module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
55MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
56#endif
57
58EXPORT_SYMBOL(jbd2_journal_extend);
59EXPORT_SYMBOL(jbd2_journal_stop);
60EXPORT_SYMBOL(jbd2_journal_lock_updates);
61EXPORT_SYMBOL(jbd2_journal_unlock_updates);
62EXPORT_SYMBOL(jbd2_journal_get_write_access);
63EXPORT_SYMBOL(jbd2_journal_get_create_access);
64EXPORT_SYMBOL(jbd2_journal_get_undo_access);
65EXPORT_SYMBOL(jbd2_journal_set_triggers);
66EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
67EXPORT_SYMBOL(jbd2_journal_forget);
68EXPORT_SYMBOL(jbd2_journal_flush);
69EXPORT_SYMBOL(jbd2_journal_revoke);
70
71EXPORT_SYMBOL(jbd2_journal_init_dev);
72EXPORT_SYMBOL(jbd2_journal_init_inode);
73EXPORT_SYMBOL(jbd2_journal_check_used_features);
74EXPORT_SYMBOL(jbd2_journal_check_available_features);
75EXPORT_SYMBOL(jbd2_journal_set_features);
76EXPORT_SYMBOL(jbd2_journal_load);
77EXPORT_SYMBOL(jbd2_journal_destroy);
78EXPORT_SYMBOL(jbd2_journal_abort);
79EXPORT_SYMBOL(jbd2_journal_errno);
80EXPORT_SYMBOL(jbd2_journal_ack_err);
81EXPORT_SYMBOL(jbd2_journal_clear_err);
82EXPORT_SYMBOL(jbd2_log_wait_commit);
83EXPORT_SYMBOL(jbd2_journal_start_commit);
84EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
85EXPORT_SYMBOL(jbd2_journal_wipe);
86EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
87EXPORT_SYMBOL(jbd2_journal_invalidate_folio);
88EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
89EXPORT_SYMBOL(jbd2_journal_force_commit);
90EXPORT_SYMBOL(jbd2_journal_inode_ranged_write);
91EXPORT_SYMBOL(jbd2_journal_inode_ranged_wait);
92EXPORT_SYMBOL(jbd2_journal_finish_inode_data_buffers);
93EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
94EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
95EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
96EXPORT_SYMBOL(jbd2_inode_cache);
97
98static int jbd2_journal_create_slab(size_t slab_size);
99
100#ifdef CONFIG_JBD2_DEBUG
101void __jbd2_debug(int level, const char *file, const char *func,
102 unsigned int line, const char *fmt, ...)
103{
104 struct va_format vaf;
105 va_list args;
106
107 if (level > jbd2_journal_enable_debug)
108 return;
109 va_start(args, fmt);
110 vaf.fmt = fmt;
111 vaf.va = &args;
112 printk(KERN_DEBUG "%s: (%s, %u): %pV", file, func, line, &vaf);
113 va_end(args);
114}
115#endif
116
117/* Checksumming functions */
118static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
119{
120 __u32 csum;
121 __be32 old_csum;
122
123 old_csum = sb->s_checksum;
124 sb->s_checksum = 0;
125 csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
126 sb->s_checksum = old_csum;
127
128 return cpu_to_be32(csum);
129}
130
131/*
132 * Helper function used to manage commit timeouts
133 */
134
135static void commit_timeout(struct timer_list *t)
136{
137 journal_t *journal = from_timer(journal, t, j_commit_timer);
138
139 wake_up_process(journal->j_task);
140}
141
142/*
143 * kjournald2: The main thread function used to manage a logging device
144 * journal.
145 *
146 * This kernel thread is responsible for two things:
147 *
148 * 1) COMMIT: Every so often we need to commit the current state of the
149 * filesystem to disk. The journal thread is responsible for writing
150 * all of the metadata buffers to disk. If a fast commit is ongoing
151 * journal thread waits until it's done and then continues from
152 * there on.
153 *
154 * 2) CHECKPOINT: We cannot reuse a used section of the log file until all
155 * of the data in that part of the log has been rewritten elsewhere on
156 * the disk. Flushing these old buffers to reclaim space in the log is
157 * known as checkpointing, and this thread is responsible for that job.
158 */
159
160static int kjournald2(void *arg)
161{
162 journal_t *journal = arg;
163 transaction_t *transaction;
164
165 /*
166 * Set up an interval timer which can be used to trigger a commit wakeup
167 * after the commit interval expires
168 */
169 timer_setup(&journal->j_commit_timer, commit_timeout, 0);
170
171 set_freezable();
172
173 /* Record that the journal thread is running */
174 journal->j_task = current;
175 wake_up(&journal->j_wait_done_commit);
176
177 /*
178 * Make sure that no allocations from this kernel thread will ever
179 * recurse to the fs layer because we are responsible for the
180 * transaction commit and any fs involvement might get stuck waiting for
181 * the trasn. commit.
182 */
183 memalloc_nofs_save();
184
185 /*
186 * And now, wait forever for commit wakeup events.
187 */
188 write_lock(&journal->j_state_lock);
189
190loop:
191 if (journal->j_flags & JBD2_UNMOUNT)
192 goto end_loop;
193
194 jbd2_debug(1, "commit_sequence=%u, commit_request=%u\n",
195 journal->j_commit_sequence, journal->j_commit_request);
196
197 if (journal->j_commit_sequence != journal->j_commit_request) {
198 jbd2_debug(1, "OK, requests differ\n");
199 write_unlock(&journal->j_state_lock);
200 del_timer_sync(&journal->j_commit_timer);
201 jbd2_journal_commit_transaction(journal);
202 write_lock(&journal->j_state_lock);
203 goto loop;
204 }
205
206 wake_up(&journal->j_wait_done_commit);
207 if (freezing(current)) {
208 /*
209 * The simpler the better. Flushing journal isn't a
210 * good idea, because that depends on threads that may
211 * be already stopped.
212 */
213 jbd2_debug(1, "Now suspending kjournald2\n");
214 write_unlock(&journal->j_state_lock);
215 try_to_freeze();
216 write_lock(&journal->j_state_lock);
217 } else {
218 /*
219 * We assume on resume that commits are already there,
220 * so we don't sleep
221 */
222 DEFINE_WAIT(wait);
223
224 prepare_to_wait(&journal->j_wait_commit, &wait,
225 TASK_INTERRUPTIBLE);
226 transaction = journal->j_running_transaction;
227 if (transaction == NULL ||
228 time_before(jiffies, transaction->t_expires)) {
229 write_unlock(&journal->j_state_lock);
230 schedule();
231 write_lock(&journal->j_state_lock);
232 }
233 finish_wait(&journal->j_wait_commit, &wait);
234 }
235
236 jbd2_debug(1, "kjournald2 wakes\n");
237
238 /*
239 * Were we woken up by a commit wakeup event?
240 */
241 transaction = journal->j_running_transaction;
242 if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
243 journal->j_commit_request = transaction->t_tid;
244 jbd2_debug(1, "woke because of timeout\n");
245 }
246 goto loop;
247
248end_loop:
249 del_timer_sync(&journal->j_commit_timer);
250 journal->j_task = NULL;
251 wake_up(&journal->j_wait_done_commit);
252 jbd2_debug(1, "Journal thread exiting.\n");
253 write_unlock(&journal->j_state_lock);
254 return 0;
255}
256
257static int jbd2_journal_start_thread(journal_t *journal)
258{
259 struct task_struct *t;
260
261 t = kthread_run(kjournald2, journal, "jbd2/%s",
262 journal->j_devname);
263 if (IS_ERR(t))
264 return PTR_ERR(t);
265
266 wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
267 return 0;
268}
269
270static void journal_kill_thread(journal_t *journal)
271{
272 write_lock(&journal->j_state_lock);
273 journal->j_flags |= JBD2_UNMOUNT;
274
275 while (journal->j_task) {
276 write_unlock(&journal->j_state_lock);
277 wake_up(&journal->j_wait_commit);
278 wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
279 write_lock(&journal->j_state_lock);
280 }
281 write_unlock(&journal->j_state_lock);
282}
283
284static inline bool jbd2_data_needs_escaping(char *data)
285{
286 return *((__be32 *)data) == cpu_to_be32(JBD2_MAGIC_NUMBER);
287}
288
289static inline void jbd2_data_do_escape(char *data)
290{
291 *((unsigned int *)data) = 0;
292}
293
294/*
295 * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
296 *
297 * Writes a metadata buffer to a given disk block. The actual IO is not
298 * performed but a new buffer_head is constructed which labels the data
299 * to be written with the correct destination disk block.
300 *
301 * Any magic-number escaping which needs to be done will cause a
302 * copy-out here. If the buffer happens to start with the
303 * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
304 * magic number is only written to the log for descripter blocks. In
305 * this case, we copy the data and replace the first word with 0, and we
306 * return a result code which indicates that this buffer needs to be
307 * marked as an escaped buffer in the corresponding log descriptor
308 * block. The missing word can then be restored when the block is read
309 * during recovery.
310 *
311 * If the source buffer has already been modified by a new transaction
312 * since we took the last commit snapshot, we use the frozen copy of
313 * that data for IO. If we end up using the existing buffer_head's data
314 * for the write, then we have to make sure nobody modifies it while the
315 * IO is in progress. do_get_write_access() handles this.
316 *
317 * The function returns a pointer to the buffer_head to be used for IO.
318 *
319 *
320 * Return value:
321 * =0: Finished OK without escape
322 * =1: Finished OK with escape
323 */
324
325int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
326 struct journal_head *jh_in,
327 struct buffer_head **bh_out,
328 sector_t blocknr)
329{
330 int do_escape = 0;
331 struct buffer_head *new_bh;
332 struct folio *new_folio;
333 unsigned int new_offset;
334 struct buffer_head *bh_in = jh2bh(jh_in);
335 journal_t *journal = transaction->t_journal;
336
337 /*
338 * The buffer really shouldn't be locked: only the current committing
339 * transaction is allowed to write it, so nobody else is allowed
340 * to do any IO.
341 *
342 * akpm: except if we're journalling data, and write() output is
343 * also part of a shared mapping, and another thread has
344 * decided to launch a writepage() against this buffer.
345 */
346 J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
347
348 new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL);
349
350 /* keep subsequent assertions sane */
351 atomic_set(&new_bh->b_count, 1);
352
353 spin_lock(&jh_in->b_state_lock);
354 /*
355 * If a new transaction has already done a buffer copy-out, then
356 * we use that version of the data for the commit.
357 */
358 if (jh_in->b_frozen_data) {
359 new_folio = virt_to_folio(jh_in->b_frozen_data);
360 new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
361 do_escape = jbd2_data_needs_escaping(jh_in->b_frozen_data);
362 if (do_escape)
363 jbd2_data_do_escape(jh_in->b_frozen_data);
364 } else {
365 char *tmp;
366 char *mapped_data;
367
368 new_folio = bh_in->b_folio;
369 new_offset = offset_in_folio(new_folio, bh_in->b_data);
370 mapped_data = kmap_local_folio(new_folio, new_offset);
371 /*
372 * Fire data frozen trigger if data already wasn't frozen. Do
373 * this before checking for escaping, as the trigger may modify
374 * the magic offset. If a copy-out happens afterwards, it will
375 * have the correct data in the buffer.
376 */
377 jbd2_buffer_frozen_trigger(jh_in, mapped_data,
378 jh_in->b_triggers);
379 do_escape = jbd2_data_needs_escaping(mapped_data);
380 kunmap_local(mapped_data);
381 /*
382 * Do we need to do a data copy?
383 */
384 if (!do_escape)
385 goto escape_done;
386
387 spin_unlock(&jh_in->b_state_lock);
388 tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS | __GFP_NOFAIL);
389 spin_lock(&jh_in->b_state_lock);
390 if (jh_in->b_frozen_data) {
391 jbd2_free(tmp, bh_in->b_size);
392 goto copy_done;
393 }
394
395 jh_in->b_frozen_data = tmp;
396 memcpy_from_folio(tmp, new_folio, new_offset, bh_in->b_size);
397 /*
398 * This isn't strictly necessary, as we're using frozen
399 * data for the escaping, but it keeps consistency with
400 * b_frozen_data usage.
401 */
402 jh_in->b_frozen_triggers = jh_in->b_triggers;
403
404copy_done:
405 new_folio = virt_to_folio(jh_in->b_frozen_data);
406 new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
407 jbd2_data_do_escape(jh_in->b_frozen_data);
408 }
409
410escape_done:
411 folio_set_bh(new_bh, new_folio, new_offset);
412 new_bh->b_size = bh_in->b_size;
413 new_bh->b_bdev = journal->j_dev;
414 new_bh->b_blocknr = blocknr;
415 new_bh->b_private = bh_in;
416 set_buffer_mapped(new_bh);
417 set_buffer_dirty(new_bh);
418
419 *bh_out = new_bh;
420
421 /*
422 * The to-be-written buffer needs to get moved to the io queue,
423 * and the original buffer whose contents we are shadowing or
424 * copying is moved to the transaction's shadow queue.
425 */
426 JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
427 spin_lock(&journal->j_list_lock);
428 __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
429 spin_unlock(&journal->j_list_lock);
430 set_buffer_shadow(bh_in);
431 spin_unlock(&jh_in->b_state_lock);
432
433 return do_escape;
434}
435
436/*
437 * Allocation code for the journal file. Manage the space left in the
438 * journal, so that we can begin checkpointing when appropriate.
439 */
440
441/*
442 * Called with j_state_lock locked for writing.
443 * Returns true if a transaction commit was started.
444 */
445static int __jbd2_log_start_commit(journal_t *journal, tid_t target)
446{
447 /* Return if the txn has already requested to be committed */
448 if (journal->j_commit_request == target)
449 return 0;
450
451 /*
452 * The only transaction we can possibly wait upon is the
453 * currently running transaction (if it exists). Otherwise,
454 * the target tid must be an old one.
455 */
456 if (journal->j_running_transaction &&
457 journal->j_running_transaction->t_tid == target) {
458 /*
459 * We want a new commit: OK, mark the request and wakeup the
460 * commit thread. We do _not_ do the commit ourselves.
461 */
462
463 journal->j_commit_request = target;
464 jbd2_debug(1, "JBD2: requesting commit %u/%u\n",
465 journal->j_commit_request,
466 journal->j_commit_sequence);
467 journal->j_running_transaction->t_requested = jiffies;
468 wake_up(&journal->j_wait_commit);
469 return 1;
470 } else if (!tid_geq(journal->j_commit_request, target))
471 /* This should never happen, but if it does, preserve
472 the evidence before kjournald goes into a loop and
473 increments j_commit_sequence beyond all recognition. */
474 WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
475 journal->j_commit_request,
476 journal->j_commit_sequence,
477 target, journal->j_running_transaction ?
478 journal->j_running_transaction->t_tid : 0);
479 return 0;
480}
481
482int jbd2_log_start_commit(journal_t *journal, tid_t tid)
483{
484 int ret;
485
486 write_lock(&journal->j_state_lock);
487 ret = __jbd2_log_start_commit(journal, tid);
488 write_unlock(&journal->j_state_lock);
489 return ret;
490}
491
492/*
493 * Force and wait any uncommitted transactions. We can only force the running
494 * transaction if we don't have an active handle, otherwise, we will deadlock.
495 * Returns: <0 in case of error,
496 * 0 if nothing to commit,
497 * 1 if transaction was successfully committed.
498 */
499static int __jbd2_journal_force_commit(journal_t *journal)
500{
501 transaction_t *transaction = NULL;
502 tid_t tid;
503 int need_to_start = 0, ret = 0;
504
505 read_lock(&journal->j_state_lock);
506 if (journal->j_running_transaction && !current->journal_info) {
507 transaction = journal->j_running_transaction;
508 if (!tid_geq(journal->j_commit_request, transaction->t_tid))
509 need_to_start = 1;
510 } else if (journal->j_committing_transaction)
511 transaction = journal->j_committing_transaction;
512
513 if (!transaction) {
514 /* Nothing to commit */
515 read_unlock(&journal->j_state_lock);
516 return 0;
517 }
518 tid = transaction->t_tid;
519 read_unlock(&journal->j_state_lock);
520 if (need_to_start)
521 jbd2_log_start_commit(journal, tid);
522 ret = jbd2_log_wait_commit(journal, tid);
523 if (!ret)
524 ret = 1;
525
526 return ret;
527}
528
529/**
530 * jbd2_journal_force_commit_nested - Force and wait upon a commit if the
531 * calling process is not within transaction.
532 *
533 * @journal: journal to force
534 * Returns true if progress was made.
535 *
536 * This is used for forcing out undo-protected data which contains
537 * bitmaps, when the fs is running out of space.
538 */
539int jbd2_journal_force_commit_nested(journal_t *journal)
540{
541 int ret;
542
543 ret = __jbd2_journal_force_commit(journal);
544 return ret > 0;
545}
546
547/**
548 * jbd2_journal_force_commit() - force any uncommitted transactions
549 * @journal: journal to force
550 *
551 * Caller want unconditional commit. We can only force the running transaction
552 * if we don't have an active handle, otherwise, we will deadlock.
553 */
554int jbd2_journal_force_commit(journal_t *journal)
555{
556 int ret;
557
558 J_ASSERT(!current->journal_info);
559 ret = __jbd2_journal_force_commit(journal);
560 if (ret > 0)
561 ret = 0;
562 return ret;
563}
564
565/*
566 * Start a commit of the current running transaction (if any). Returns true
567 * if a transaction is going to be committed (or is currently already
568 * committing), and fills its tid in at *ptid
569 */
570int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
571{
572 int ret = 0;
573
574 write_lock(&journal->j_state_lock);
575 if (journal->j_running_transaction) {
576 tid_t tid = journal->j_running_transaction->t_tid;
577
578 __jbd2_log_start_commit(journal, tid);
579 /* There's a running transaction and we've just made sure
580 * it's commit has been scheduled. */
581 if (ptid)
582 *ptid = tid;
583 ret = 1;
584 } else if (journal->j_committing_transaction) {
585 /*
586 * If commit has been started, then we have to wait for
587 * completion of that transaction.
588 */
589 if (ptid)
590 *ptid = journal->j_committing_transaction->t_tid;
591 ret = 1;
592 }
593 write_unlock(&journal->j_state_lock);
594 return ret;
595}
596
597/*
598 * Return 1 if a given transaction has not yet sent barrier request
599 * connected with a transaction commit. If 0 is returned, transaction
600 * may or may not have sent the barrier. Used to avoid sending barrier
601 * twice in common cases.
602 */
603int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
604{
605 int ret = 0;
606 transaction_t *commit_trans;
607
608 if (!(journal->j_flags & JBD2_BARRIER))
609 return 0;
610 read_lock(&journal->j_state_lock);
611 /* Transaction already committed? */
612 if (tid_geq(journal->j_commit_sequence, tid))
613 goto out;
614 commit_trans = journal->j_committing_transaction;
615 if (!commit_trans || commit_trans->t_tid != tid) {
616 ret = 1;
617 goto out;
618 }
619 /*
620 * Transaction is being committed and we already proceeded to
621 * submitting a flush to fs partition?
622 */
623 if (journal->j_fs_dev != journal->j_dev) {
624 if (!commit_trans->t_need_data_flush ||
625 commit_trans->t_state >= T_COMMIT_DFLUSH)
626 goto out;
627 } else {
628 if (commit_trans->t_state >= T_COMMIT_JFLUSH)
629 goto out;
630 }
631 ret = 1;
632out:
633 read_unlock(&journal->j_state_lock);
634 return ret;
635}
636EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
637
638/*
639 * Wait for a specified commit to complete.
640 * The caller may not hold the journal lock.
641 */
642int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
643{
644 int err = 0;
645
646 read_lock(&journal->j_state_lock);
647#ifdef CONFIG_PROVE_LOCKING
648 /*
649 * Some callers make sure transaction is already committing and in that
650 * case we cannot block on open handles anymore. So don't warn in that
651 * case.
652 */
653 if (tid_gt(tid, journal->j_commit_sequence) &&
654 (!journal->j_committing_transaction ||
655 journal->j_committing_transaction->t_tid != tid)) {
656 read_unlock(&journal->j_state_lock);
657 jbd2_might_wait_for_commit(journal);
658 read_lock(&journal->j_state_lock);
659 }
660#endif
661#ifdef CONFIG_JBD2_DEBUG
662 if (!tid_geq(journal->j_commit_request, tid)) {
663 printk(KERN_ERR
664 "%s: error: j_commit_request=%u, tid=%u\n",
665 __func__, journal->j_commit_request, tid);
666 }
667#endif
668 while (tid_gt(tid, journal->j_commit_sequence)) {
669 jbd2_debug(1, "JBD2: want %u, j_commit_sequence=%u\n",
670 tid, journal->j_commit_sequence);
671 read_unlock(&journal->j_state_lock);
672 wake_up(&journal->j_wait_commit);
673 wait_event(journal->j_wait_done_commit,
674 !tid_gt(tid, journal->j_commit_sequence));
675 read_lock(&journal->j_state_lock);
676 }
677 read_unlock(&journal->j_state_lock);
678
679 if (unlikely(is_journal_aborted(journal)))
680 err = -EIO;
681 return err;
682}
683
684/*
685 * Start a fast commit. If there's an ongoing fast or full commit wait for
686 * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY
687 * if a fast commit is not needed, either because there's an already a commit
688 * going on or this tid has already been committed. Returns -EINVAL if no jbd2
689 * commit has yet been performed.
690 */
691int jbd2_fc_begin_commit(journal_t *journal, tid_t tid)
692{
693 if (unlikely(is_journal_aborted(journal)))
694 return -EIO;
695 /*
696 * Fast commits only allowed if at least one full commit has
697 * been processed.
698 */
699 if (!journal->j_stats.ts_tid)
700 return -EINVAL;
701
702 write_lock(&journal->j_state_lock);
703 if (tid_geq(journal->j_commit_sequence, tid)) {
704 write_unlock(&journal->j_state_lock);
705 return -EALREADY;
706 }
707
708 if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
709 (journal->j_flags & JBD2_FAST_COMMIT_ONGOING)) {
710 DEFINE_WAIT(wait);
711
712 prepare_to_wait(&journal->j_fc_wait, &wait,
713 TASK_UNINTERRUPTIBLE);
714 write_unlock(&journal->j_state_lock);
715 schedule();
716 finish_wait(&journal->j_fc_wait, &wait);
717 return -EALREADY;
718 }
719 journal->j_flags |= JBD2_FAST_COMMIT_ONGOING;
720 write_unlock(&journal->j_state_lock);
721 jbd2_journal_lock_updates(journal);
722
723 return 0;
724}
725EXPORT_SYMBOL(jbd2_fc_begin_commit);
726
727/*
728 * Stop a fast commit. If fallback is set, this function starts commit of
729 * TID tid before any other fast commit can start.
730 */
731static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback)
732{
733 if (journal->j_fc_cleanup_callback)
734 journal->j_fc_cleanup_callback(journal, 0, tid);
735 jbd2_journal_unlock_updates(journal);
736 write_lock(&journal->j_state_lock);
737 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
738 if (fallback)
739 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
740 write_unlock(&journal->j_state_lock);
741 wake_up(&journal->j_fc_wait);
742 if (fallback)
743 return jbd2_complete_transaction(journal, tid);
744 return 0;
745}
746
747int jbd2_fc_end_commit(journal_t *journal)
748{
749 return __jbd2_fc_end_commit(journal, 0, false);
750}
751EXPORT_SYMBOL(jbd2_fc_end_commit);
752
753int jbd2_fc_end_commit_fallback(journal_t *journal)
754{
755 tid_t tid;
756
757 read_lock(&journal->j_state_lock);
758 tid = journal->j_running_transaction ?
759 journal->j_running_transaction->t_tid : 0;
760 read_unlock(&journal->j_state_lock);
761 return __jbd2_fc_end_commit(journal, tid, true);
762}
763EXPORT_SYMBOL(jbd2_fc_end_commit_fallback);
764
765/* Return 1 when transaction with given tid has already committed. */
766int jbd2_transaction_committed(journal_t *journal, tid_t tid)
767{
768 return tid_geq(READ_ONCE(journal->j_commit_sequence), tid);
769}
770EXPORT_SYMBOL(jbd2_transaction_committed);
771
772/*
773 * When this function returns the transaction corresponding to tid
774 * will be completed. If the transaction has currently running, start
775 * committing that transaction before waiting for it to complete. If
776 * the transaction id is stale, it is by definition already completed,
777 * so just return SUCCESS.
778 */
779int jbd2_complete_transaction(journal_t *journal, tid_t tid)
780{
781 int need_to_wait = 1;
782
783 read_lock(&journal->j_state_lock);
784 if (journal->j_running_transaction &&
785 journal->j_running_transaction->t_tid == tid) {
786 if (journal->j_commit_request != tid) {
787 /* transaction not yet started, so request it */
788 read_unlock(&journal->j_state_lock);
789 jbd2_log_start_commit(journal, tid);
790 goto wait_commit;
791 }
792 } else if (!(journal->j_committing_transaction &&
793 journal->j_committing_transaction->t_tid == tid))
794 need_to_wait = 0;
795 read_unlock(&journal->j_state_lock);
796 if (!need_to_wait)
797 return 0;
798wait_commit:
799 return jbd2_log_wait_commit(journal, tid);
800}
801EXPORT_SYMBOL(jbd2_complete_transaction);
802
803/*
804 * Log buffer allocation routines:
805 */
806
807int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
808{
809 unsigned long blocknr;
810
811 write_lock(&journal->j_state_lock);
812 J_ASSERT(journal->j_free > 1);
813
814 blocknr = journal->j_head;
815 journal->j_head++;
816 journal->j_free--;
817 if (journal->j_head == journal->j_last)
818 journal->j_head = journal->j_first;
819 write_unlock(&journal->j_state_lock);
820 return jbd2_journal_bmap(journal, blocknr, retp);
821}
822
823/* Map one fast commit buffer for use by the file system */
824int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out)
825{
826 unsigned long long pblock;
827 unsigned long blocknr;
828 int ret = 0;
829 struct buffer_head *bh;
830 int fc_off;
831
832 *bh_out = NULL;
833
834 if (journal->j_fc_off + journal->j_fc_first >= journal->j_fc_last)
835 return -EINVAL;
836
837 fc_off = journal->j_fc_off;
838 blocknr = journal->j_fc_first + fc_off;
839 journal->j_fc_off++;
840 ret = jbd2_journal_bmap(journal, blocknr, &pblock);
841 if (ret)
842 return ret;
843
844 bh = __getblk(journal->j_dev, pblock, journal->j_blocksize);
845 if (!bh)
846 return -ENOMEM;
847
848 journal->j_fc_wbuf[fc_off] = bh;
849
850 *bh_out = bh;
851
852 return 0;
853}
854EXPORT_SYMBOL(jbd2_fc_get_buf);
855
856/*
857 * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf
858 * for completion.
859 */
860int jbd2_fc_wait_bufs(journal_t *journal, int num_blks)
861{
862 struct buffer_head *bh;
863 int i, j_fc_off;
864
865 j_fc_off = journal->j_fc_off;
866
867 /*
868 * Wait in reverse order to minimize chances of us being woken up before
869 * all IOs have completed
870 */
871 for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) {
872 bh = journal->j_fc_wbuf[i];
873 wait_on_buffer(bh);
874 /*
875 * Update j_fc_off so jbd2_fc_release_bufs can release remain
876 * buffer head.
877 */
878 if (unlikely(!buffer_uptodate(bh))) {
879 journal->j_fc_off = i + 1;
880 return -EIO;
881 }
882 put_bh(bh);
883 journal->j_fc_wbuf[i] = NULL;
884 }
885
886 return 0;
887}
888EXPORT_SYMBOL(jbd2_fc_wait_bufs);
889
890void jbd2_fc_release_bufs(journal_t *journal)
891{
892 struct buffer_head *bh;
893 int i, j_fc_off;
894
895 j_fc_off = journal->j_fc_off;
896
897 for (i = j_fc_off - 1; i >= 0; i--) {
898 bh = journal->j_fc_wbuf[i];
899 if (!bh)
900 break;
901 put_bh(bh);
902 journal->j_fc_wbuf[i] = NULL;
903 }
904}
905EXPORT_SYMBOL(jbd2_fc_release_bufs);
906
907/*
908 * Conversion of logical to physical block numbers for the journal
909 *
910 * On external journals the journal blocks are identity-mapped, so
911 * this is a no-op. If needed, we can use j_blk_offset - everything is
912 * ready.
913 */
914int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
915 unsigned long long *retp)
916{
917 int err = 0;
918 unsigned long long ret;
919 sector_t block = blocknr;
920
921 if (journal->j_bmap) {
922 err = journal->j_bmap(journal, &block);
923 if (err == 0)
924 *retp = block;
925 } else if (journal->j_inode) {
926 ret = bmap(journal->j_inode, &block);
927
928 if (ret || !block) {
929 printk(KERN_ALERT "%s: journal block not found "
930 "at offset %lu on %s\n",
931 __func__, blocknr, journal->j_devname);
932 err = -EIO;
933 jbd2_journal_abort(journal, err);
934 } else {
935 *retp = block;
936 }
937
938 } else {
939 *retp = blocknr; /* +journal->j_blk_offset */
940 }
941 return err;
942}
943
944/*
945 * We play buffer_head aliasing tricks to write data/metadata blocks to
946 * the journal without copying their contents, but for journal
947 * descriptor blocks we do need to generate bona fide buffers.
948 *
949 * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
950 * the buffer's contents they really should run flush_dcache_page(bh->b_page).
951 * But we don't bother doing that, so there will be coherency problems with
952 * mmaps of blockdevs which hold live JBD-controlled filesystems.
953 */
954struct buffer_head *
955jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type)
956{
957 journal_t *journal = transaction->t_journal;
958 struct buffer_head *bh;
959 unsigned long long blocknr;
960 journal_header_t *header;
961 int err;
962
963 err = jbd2_journal_next_log_block(journal, &blocknr);
964
965 if (err)
966 return NULL;
967
968 bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
969 if (!bh)
970 return NULL;
971 atomic_dec(&transaction->t_outstanding_credits);
972 lock_buffer(bh);
973 memset(bh->b_data, 0, journal->j_blocksize);
974 header = (journal_header_t *)bh->b_data;
975 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
976 header->h_blocktype = cpu_to_be32(type);
977 header->h_sequence = cpu_to_be32(transaction->t_tid);
978 set_buffer_uptodate(bh);
979 unlock_buffer(bh);
980 BUFFER_TRACE(bh, "return this buffer");
981 return bh;
982}
983
984void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh)
985{
986 struct jbd2_journal_block_tail *tail;
987 __u32 csum;
988
989 if (!jbd2_journal_has_csum_v2or3(j))
990 return;
991
992 tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
993 sizeof(struct jbd2_journal_block_tail));
994 tail->t_checksum = 0;
995 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
996 tail->t_checksum = cpu_to_be32(csum);
997}
998
999/*
1000 * Return tid of the oldest transaction in the journal and block in the journal
1001 * where the transaction starts.
1002 *
1003 * If the journal is now empty, return which will be the next transaction ID
1004 * we will write and where will that transaction start.
1005 *
1006 * The return value is 0 if journal tail cannot be pushed any further, 1 if
1007 * it can.
1008 */
1009int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
1010 unsigned long *block)
1011{
1012 transaction_t *transaction;
1013 int ret;
1014
1015 read_lock(&journal->j_state_lock);
1016 spin_lock(&journal->j_list_lock);
1017 transaction = journal->j_checkpoint_transactions;
1018 if (transaction) {
1019 *tid = transaction->t_tid;
1020 *block = transaction->t_log_start;
1021 } else if ((transaction = journal->j_committing_transaction) != NULL) {
1022 *tid = transaction->t_tid;
1023 *block = transaction->t_log_start;
1024 } else if ((transaction = journal->j_running_transaction) != NULL) {
1025 *tid = transaction->t_tid;
1026 *block = journal->j_head;
1027 } else {
1028 *tid = journal->j_transaction_sequence;
1029 *block = journal->j_head;
1030 }
1031 ret = tid_gt(*tid, journal->j_tail_sequence);
1032 spin_unlock(&journal->j_list_lock);
1033 read_unlock(&journal->j_state_lock);
1034
1035 return ret;
1036}
1037
1038/*
1039 * Update information in journal structure and in on disk journal superblock
1040 * about log tail. This function does not check whether information passed in
1041 * really pushes log tail further. It's responsibility of the caller to make
1042 * sure provided log tail information is valid (e.g. by holding
1043 * j_checkpoint_mutex all the time between computing log tail and calling this
1044 * function as is the case with jbd2_cleanup_journal_tail()).
1045 *
1046 * Requires j_checkpoint_mutex
1047 */
1048int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1049{
1050 unsigned long freed;
1051 int ret;
1052
1053 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1054
1055 /*
1056 * We cannot afford for write to remain in drive's caches since as
1057 * soon as we update j_tail, next transaction can start reusing journal
1058 * space and if we lose sb update during power failure we'd replay
1059 * old transaction with possibly newly overwritten data.
1060 */
1061 ret = jbd2_journal_update_sb_log_tail(journal, tid, block, REQ_FUA);
1062 if (ret)
1063 goto out;
1064
1065 write_lock(&journal->j_state_lock);
1066 freed = block - journal->j_tail;
1067 if (block < journal->j_tail)
1068 freed += journal->j_last - journal->j_first;
1069
1070 trace_jbd2_update_log_tail(journal, tid, block, freed);
1071 jbd2_debug(1,
1072 "Cleaning journal tail from %u to %u (offset %lu), "
1073 "freeing %lu\n",
1074 journal->j_tail_sequence, tid, block, freed);
1075
1076 journal->j_free += freed;
1077 journal->j_tail_sequence = tid;
1078 journal->j_tail = block;
1079 write_unlock(&journal->j_state_lock);
1080
1081out:
1082 return ret;
1083}
1084
1085/*
1086 * This is a variation of __jbd2_update_log_tail which checks for validity of
1087 * provided log tail and locks j_checkpoint_mutex. So it is safe against races
1088 * with other threads updating log tail.
1089 */
1090void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
1091{
1092 mutex_lock_io(&journal->j_checkpoint_mutex);
1093 if (tid_gt(tid, journal->j_tail_sequence))
1094 __jbd2_update_log_tail(journal, tid, block);
1095 mutex_unlock(&journal->j_checkpoint_mutex);
1096}
1097
1098struct jbd2_stats_proc_session {
1099 journal_t *journal;
1100 struct transaction_stats_s *stats;
1101 int start;
1102 int max;
1103};
1104
1105static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
1106{
1107 return *pos ? NULL : SEQ_START_TOKEN;
1108}
1109
1110static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
1111{
1112 (*pos)++;
1113 return NULL;
1114}
1115
1116static int jbd2_seq_info_show(struct seq_file *seq, void *v)
1117{
1118 struct jbd2_stats_proc_session *s = seq->private;
1119
1120 if (v != SEQ_START_TOKEN)
1121 return 0;
1122 seq_printf(seq, "%lu transactions (%lu requested), "
1123 "each up to %u blocks\n",
1124 s->stats->ts_tid, s->stats->ts_requested,
1125 s->journal->j_max_transaction_buffers);
1126 if (s->stats->ts_tid == 0)
1127 return 0;
1128 seq_printf(seq, "average: \n %ums waiting for transaction\n",
1129 jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
1130 seq_printf(seq, " %ums request delay\n",
1131 (s->stats->ts_requested == 0) ? 0 :
1132 jiffies_to_msecs(s->stats->run.rs_request_delay /
1133 s->stats->ts_requested));
1134 seq_printf(seq, " %ums running transaction\n",
1135 jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
1136 seq_printf(seq, " %ums transaction was being locked\n",
1137 jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
1138 seq_printf(seq, " %ums flushing data (in ordered mode)\n",
1139 jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
1140 seq_printf(seq, " %ums logging transaction\n",
1141 jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
1142 seq_printf(seq, " %lluus average transaction commit time\n",
1143 div_u64(s->journal->j_average_commit_time, 1000));
1144 seq_printf(seq, " %lu handles per transaction\n",
1145 s->stats->run.rs_handle_count / s->stats->ts_tid);
1146 seq_printf(seq, " %lu blocks per transaction\n",
1147 s->stats->run.rs_blocks / s->stats->ts_tid);
1148 seq_printf(seq, " %lu logged blocks per transaction\n",
1149 s->stats->run.rs_blocks_logged / s->stats->ts_tid);
1150 return 0;
1151}
1152
1153static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
1154{
1155}
1156
1157static const struct seq_operations jbd2_seq_info_ops = {
1158 .start = jbd2_seq_info_start,
1159 .next = jbd2_seq_info_next,
1160 .stop = jbd2_seq_info_stop,
1161 .show = jbd2_seq_info_show,
1162};
1163
1164static int jbd2_seq_info_open(struct inode *inode, struct file *file)
1165{
1166 journal_t *journal = pde_data(inode);
1167 struct jbd2_stats_proc_session *s;
1168 int rc, size;
1169
1170 s = kmalloc(sizeof(*s), GFP_KERNEL);
1171 if (s == NULL)
1172 return -ENOMEM;
1173 size = sizeof(struct transaction_stats_s);
1174 s->stats = kmalloc(size, GFP_KERNEL);
1175 if (s->stats == NULL) {
1176 kfree(s);
1177 return -ENOMEM;
1178 }
1179 spin_lock(&journal->j_history_lock);
1180 memcpy(s->stats, &journal->j_stats, size);
1181 s->journal = journal;
1182 spin_unlock(&journal->j_history_lock);
1183
1184 rc = seq_open(file, &jbd2_seq_info_ops);
1185 if (rc == 0) {
1186 struct seq_file *m = file->private_data;
1187 m->private = s;
1188 } else {
1189 kfree(s->stats);
1190 kfree(s);
1191 }
1192 return rc;
1193
1194}
1195
1196static int jbd2_seq_info_release(struct inode *inode, struct file *file)
1197{
1198 struct seq_file *seq = file->private_data;
1199 struct jbd2_stats_proc_session *s = seq->private;
1200 kfree(s->stats);
1201 kfree(s);
1202 return seq_release(inode, file);
1203}
1204
1205static const struct proc_ops jbd2_info_proc_ops = {
1206 .proc_open = jbd2_seq_info_open,
1207 .proc_read = seq_read,
1208 .proc_lseek = seq_lseek,
1209 .proc_release = jbd2_seq_info_release,
1210};
1211
1212static struct proc_dir_entry *proc_jbd2_stats;
1213
1214static void jbd2_stats_proc_init(journal_t *journal)
1215{
1216 journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
1217 if (journal->j_proc_entry) {
1218 proc_create_data("info", S_IRUGO, journal->j_proc_entry,
1219 &jbd2_info_proc_ops, journal);
1220 }
1221}
1222
1223static void jbd2_stats_proc_exit(journal_t *journal)
1224{
1225 remove_proc_entry("info", journal->j_proc_entry);
1226 remove_proc_entry(journal->j_devname, proc_jbd2_stats);
1227}
1228
1229/* Minimum size of descriptor tag */
1230static int jbd2_min_tag_size(void)
1231{
1232 /*
1233 * Tag with 32-bit block numbers does not use last four bytes of the
1234 * structure
1235 */
1236 return sizeof(journal_block_tag_t) - 4;
1237}
1238
1239/**
1240 * jbd2_journal_shrink_scan()
1241 * @shrink: shrinker to work on
1242 * @sc: reclaim request to process
1243 *
1244 * Scan the checkpointed buffer on the checkpoint list and release the
1245 * journal_head.
1246 */
1247static unsigned long jbd2_journal_shrink_scan(struct shrinker *shrink,
1248 struct shrink_control *sc)
1249{
1250 journal_t *journal = shrink->private_data;
1251 unsigned long nr_to_scan = sc->nr_to_scan;
1252 unsigned long nr_shrunk;
1253 unsigned long count;
1254
1255 count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1256 trace_jbd2_shrink_scan_enter(journal, sc->nr_to_scan, count);
1257
1258 nr_shrunk = jbd2_journal_shrink_checkpoint_list(journal, &nr_to_scan);
1259
1260 count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1261 trace_jbd2_shrink_scan_exit(journal, nr_to_scan, nr_shrunk, count);
1262
1263 return nr_shrunk;
1264}
1265
1266/**
1267 * jbd2_journal_shrink_count()
1268 * @shrink: shrinker to work on
1269 * @sc: reclaim request to process
1270 *
1271 * Count the number of checkpoint buffers on the checkpoint list.
1272 */
1273static unsigned long jbd2_journal_shrink_count(struct shrinker *shrink,
1274 struct shrink_control *sc)
1275{
1276 journal_t *journal = shrink->private_data;
1277 unsigned long count;
1278
1279 count = percpu_counter_read_positive(&journal->j_checkpoint_jh_count);
1280 trace_jbd2_shrink_count(journal, sc->nr_to_scan, count);
1281
1282 return count;
1283}
1284
1285/*
1286 * If the journal init or create aborts, we need to mark the journal
1287 * superblock as being NULL to prevent the journal destroy from writing
1288 * back a bogus superblock.
1289 */
1290static void journal_fail_superblock(journal_t *journal)
1291{
1292 struct buffer_head *bh = journal->j_sb_buffer;
1293 brelse(bh);
1294 journal->j_sb_buffer = NULL;
1295}
1296
1297/*
1298 * Check the superblock for a given journal, performing initial
1299 * validation of the format.
1300 */
1301static int journal_check_superblock(journal_t *journal)
1302{
1303 journal_superblock_t *sb = journal->j_superblock;
1304 int num_fc_blks;
1305 int err = -EINVAL;
1306
1307 if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
1308 sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
1309 printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
1310 return err;
1311 }
1312
1313 if (be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V1 &&
1314 be32_to_cpu(sb->s_header.h_blocktype) != JBD2_SUPERBLOCK_V2) {
1315 printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
1316 return err;
1317 }
1318
1319 if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) {
1320 printk(KERN_WARNING "JBD2: journal file too short\n");
1321 return err;
1322 }
1323
1324 if (be32_to_cpu(sb->s_first) == 0 ||
1325 be32_to_cpu(sb->s_first) >= journal->j_total_len) {
1326 printk(KERN_WARNING
1327 "JBD2: Invalid start block of journal: %u\n",
1328 be32_to_cpu(sb->s_first));
1329 return err;
1330 }
1331
1332 /*
1333 * If this is a V2 superblock, then we have to check the
1334 * features flags on it.
1335 */
1336 if (!jbd2_format_support_feature(journal))
1337 return 0;
1338
1339 if ((sb->s_feature_ro_compat &
1340 ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
1341 (sb->s_feature_incompat &
1342 ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
1343 printk(KERN_WARNING "JBD2: Unrecognised features on journal\n");
1344 return err;
1345 }
1346
1347 num_fc_blks = jbd2_has_feature_fast_commit(journal) ?
1348 jbd2_journal_get_num_fc_blks(sb) : 0;
1349 if (be32_to_cpu(sb->s_maxlen) < JBD2_MIN_JOURNAL_BLOCKS ||
1350 be32_to_cpu(sb->s_maxlen) - JBD2_MIN_JOURNAL_BLOCKS < num_fc_blks) {
1351 printk(KERN_ERR "JBD2: journal file too short %u,%d\n",
1352 be32_to_cpu(sb->s_maxlen), num_fc_blks);
1353 return err;
1354 }
1355
1356 if (jbd2_has_feature_csum2(journal) &&
1357 jbd2_has_feature_csum3(journal)) {
1358 /* Can't have checksum v2 and v3 at the same time! */
1359 printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 "
1360 "at the same time!\n");
1361 return err;
1362 }
1363
1364 if (jbd2_journal_has_csum_v2or3_feature(journal) &&
1365 jbd2_has_feature_checksum(journal)) {
1366 /* Can't have checksum v1 and v2 on at the same time! */
1367 printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 "
1368 "at the same time!\n");
1369 return err;
1370 }
1371
1372 /* Load the checksum driver */
1373 if (jbd2_journal_has_csum_v2or3_feature(journal)) {
1374 if (sb->s_checksum_type != JBD2_CRC32C_CHKSUM) {
1375 printk(KERN_ERR "JBD2: Unknown checksum type\n");
1376 return err;
1377 }
1378
1379 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
1380 if (IS_ERR(journal->j_chksum_driver)) {
1381 printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
1382 err = PTR_ERR(journal->j_chksum_driver);
1383 journal->j_chksum_driver = NULL;
1384 return err;
1385 }
1386 /* Check superblock checksum */
1387 if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) {
1388 printk(KERN_ERR "JBD2: journal checksum error\n");
1389 err = -EFSBADCRC;
1390 return err;
1391 }
1392 }
1393
1394 return 0;
1395}
1396
1397static int journal_revoke_records_per_block(journal_t *journal)
1398{
1399 int record_size;
1400 int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t);
1401
1402 if (jbd2_has_feature_64bit(journal))
1403 record_size = 8;
1404 else
1405 record_size = 4;
1406
1407 if (jbd2_journal_has_csum_v2or3(journal))
1408 space -= sizeof(struct jbd2_journal_block_tail);
1409 return space / record_size;
1410}
1411
1412static int jbd2_journal_get_max_txn_bufs(journal_t *journal)
1413{
1414 return (journal->j_total_len - journal->j_fc_wbufsize) / 3;
1415}
1416
1417/*
1418 * Base amount of descriptor blocks we reserve for each transaction.
1419 */
1420static int jbd2_descriptor_blocks_per_trans(journal_t *journal)
1421{
1422 int tag_space = journal->j_blocksize - sizeof(journal_header_t);
1423 int tags_per_block;
1424
1425 /* Subtract UUID */
1426 tag_space -= 16;
1427 if (jbd2_journal_has_csum_v2or3(journal))
1428 tag_space -= sizeof(struct jbd2_journal_block_tail);
1429 /* Commit code leaves a slack space of 16 bytes at the end of block */
1430 tags_per_block = (tag_space - 16) / journal_tag_bytes(journal);
1431 /*
1432 * Revoke descriptors are accounted separately so we need to reserve
1433 * space for commit block and normal transaction descriptor blocks.
1434 */
1435 return 1 + DIV_ROUND_UP(jbd2_journal_get_max_txn_bufs(journal),
1436 tags_per_block);
1437}
1438
1439/*
1440 * Initialize number of blocks each transaction reserves for its bookkeeping
1441 * and maximum number of blocks a transaction can use. This needs to be called
1442 * after the journal size and the fastcommit area size are initialized.
1443 */
1444static void jbd2_journal_init_transaction_limits(journal_t *journal)
1445{
1446 journal->j_revoke_records_per_block =
1447 journal_revoke_records_per_block(journal);
1448 journal->j_transaction_overhead_buffers =
1449 jbd2_descriptor_blocks_per_trans(journal);
1450 journal->j_max_transaction_buffers =
1451 jbd2_journal_get_max_txn_bufs(journal);
1452}
1453
1454/*
1455 * Load the on-disk journal superblock and read the key fields into the
1456 * journal_t.
1457 */
1458static int journal_load_superblock(journal_t *journal)
1459{
1460 int err;
1461 struct buffer_head *bh;
1462 journal_superblock_t *sb;
1463
1464 bh = getblk_unmovable(journal->j_dev, journal->j_blk_offset,
1465 journal->j_blocksize);
1466 if (bh)
1467 err = bh_read(bh, 0);
1468 if (!bh || err < 0) {
1469 pr_err("%s: Cannot read journal superblock\n", __func__);
1470 brelse(bh);
1471 return -EIO;
1472 }
1473
1474 journal->j_sb_buffer = bh;
1475 sb = (journal_superblock_t *)bh->b_data;
1476 journal->j_superblock = sb;
1477 err = journal_check_superblock(journal);
1478 if (err) {
1479 journal_fail_superblock(journal);
1480 return err;
1481 }
1482
1483 journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
1484 journal->j_tail = be32_to_cpu(sb->s_start);
1485 journal->j_first = be32_to_cpu(sb->s_first);
1486 journal->j_errno = be32_to_cpu(sb->s_errno);
1487 journal->j_last = be32_to_cpu(sb->s_maxlen);
1488
1489 if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len)
1490 journal->j_total_len = be32_to_cpu(sb->s_maxlen);
1491 /* Precompute checksum seed for all metadata */
1492 if (jbd2_journal_has_csum_v2or3(journal))
1493 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
1494 sizeof(sb->s_uuid));
1495 /* After journal features are set, we can compute transaction limits */
1496 jbd2_journal_init_transaction_limits(journal);
1497
1498 if (jbd2_has_feature_fast_commit(journal)) {
1499 journal->j_fc_last = be32_to_cpu(sb->s_maxlen);
1500 journal->j_last = journal->j_fc_last -
1501 jbd2_journal_get_num_fc_blks(sb);
1502 journal->j_fc_first = journal->j_last + 1;
1503 journal->j_fc_off = 0;
1504 }
1505
1506 return 0;
1507}
1508
1509
1510/*
1511 * Management for journal control blocks: functions to create and
1512 * destroy journal_t structures, and to initialise and read existing
1513 * journal blocks from disk. */
1514
1515/* The journal_init_common() function creates and fills a journal_t object
1516 * in memory. It calls journal_load_superblock() to load the on-disk journal
1517 * superblock and initialize the journal_t object.
1518 */
1519
1520static journal_t *journal_init_common(struct block_device *bdev,
1521 struct block_device *fs_dev,
1522 unsigned long long start, int len, int blocksize)
1523{
1524 static struct lock_class_key jbd2_trans_commit_key;
1525 journal_t *journal;
1526 int err;
1527 int n;
1528
1529 journal = kzalloc(sizeof(*journal), GFP_KERNEL);
1530 if (!journal)
1531 return ERR_PTR(-ENOMEM);
1532
1533 journal->j_blocksize = blocksize;
1534 journal->j_dev = bdev;
1535 journal->j_fs_dev = fs_dev;
1536 journal->j_blk_offset = start;
1537 journal->j_total_len = len;
1538 jbd2_init_fs_dev_write_error(journal);
1539
1540 err = journal_load_superblock(journal);
1541 if (err)
1542 goto err_cleanup;
1543
1544 init_waitqueue_head(&journal->j_wait_transaction_locked);
1545 init_waitqueue_head(&journal->j_wait_done_commit);
1546 init_waitqueue_head(&journal->j_wait_commit);
1547 init_waitqueue_head(&journal->j_wait_updates);
1548 init_waitqueue_head(&journal->j_wait_reserved);
1549 init_waitqueue_head(&journal->j_fc_wait);
1550 mutex_init(&journal->j_abort_mutex);
1551 mutex_init(&journal->j_barrier);
1552 mutex_init(&journal->j_checkpoint_mutex);
1553 spin_lock_init(&journal->j_revoke_lock);
1554 spin_lock_init(&journal->j_list_lock);
1555 spin_lock_init(&journal->j_history_lock);
1556 rwlock_init(&journal->j_state_lock);
1557
1558 journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
1559 journal->j_min_batch_time = 0;
1560 journal->j_max_batch_time = 15000; /* 15ms */
1561 atomic_set(&journal->j_reserved_credits, 0);
1562 lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle",
1563 &jbd2_trans_commit_key, 0);
1564
1565 /* The journal is marked for error until we succeed with recovery! */
1566 journal->j_flags = JBD2_ABORT;
1567
1568 /* Set up a default-sized revoke table for the new mount. */
1569 err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
1570 if (err)
1571 goto err_cleanup;
1572
1573 /*
1574 * journal descriptor can store up to n blocks, we need enough
1575 * buffers to write out full descriptor block.
1576 */
1577 err = -ENOMEM;
1578 n = journal->j_blocksize / jbd2_min_tag_size();
1579 journal->j_wbufsize = n;
1580 journal->j_fc_wbuf = NULL;
1581 journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *),
1582 GFP_KERNEL);
1583 if (!journal->j_wbuf)
1584 goto err_cleanup;
1585
1586 err = percpu_counter_init(&journal->j_checkpoint_jh_count, 0,
1587 GFP_KERNEL);
1588 if (err)
1589 goto err_cleanup;
1590
1591 journal->j_shrink_transaction = NULL;
1592
1593 journal->j_shrinker = shrinker_alloc(0, "jbd2-journal:(%u:%u)",
1594 MAJOR(bdev->bd_dev),
1595 MINOR(bdev->bd_dev));
1596 if (!journal->j_shrinker) {
1597 err = -ENOMEM;
1598 goto err_cleanup;
1599 }
1600
1601 journal->j_shrinker->scan_objects = jbd2_journal_shrink_scan;
1602 journal->j_shrinker->count_objects = jbd2_journal_shrink_count;
1603 journal->j_shrinker->private_data = journal;
1604
1605 shrinker_register(journal->j_shrinker);
1606
1607 return journal;
1608
1609err_cleanup:
1610 percpu_counter_destroy(&journal->j_checkpoint_jh_count);
1611 if (journal->j_chksum_driver)
1612 crypto_free_shash(journal->j_chksum_driver);
1613 kfree(journal->j_wbuf);
1614 jbd2_journal_destroy_revoke(journal);
1615 journal_fail_superblock(journal);
1616 kfree(journal);
1617 return ERR_PTR(err);
1618}
1619
1620/* jbd2_journal_init_dev and jbd2_journal_init_inode:
1621 *
1622 * Create a journal structure assigned some fixed set of disk blocks to
1623 * the journal. We don't actually touch those disk blocks yet, but we
1624 * need to set up all of the mapping information to tell the journaling
1625 * system where the journal blocks are.
1626 *
1627 */
1628
1629/**
1630 * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
1631 * @bdev: Block device on which to create the journal
1632 * @fs_dev: Device which hold journalled filesystem for this journal.
1633 * @start: Block nr Start of journal.
1634 * @len: Length of the journal in blocks.
1635 * @blocksize: blocksize of journalling device
1636 *
1637 * Returns: a newly created journal_t *
1638 *
1639 * jbd2_journal_init_dev creates a journal which maps a fixed contiguous
1640 * range of blocks on an arbitrary block device.
1641 *
1642 */
1643journal_t *jbd2_journal_init_dev(struct block_device *bdev,
1644 struct block_device *fs_dev,
1645 unsigned long long start, int len, int blocksize)
1646{
1647 journal_t *journal;
1648
1649 journal = journal_init_common(bdev, fs_dev, start, len, blocksize);
1650 if (IS_ERR(journal))
1651 return ERR_CAST(journal);
1652
1653 snprintf(journal->j_devname, sizeof(journal->j_devname),
1654 "%pg", journal->j_dev);
1655 strreplace(journal->j_devname, '/', '!');
1656 jbd2_stats_proc_init(journal);
1657
1658 return journal;
1659}
1660
1661/**
1662 * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
1663 * @inode: An inode to create the journal in
1664 *
1665 * jbd2_journal_init_inode creates a journal which maps an on-disk inode as
1666 * the journal. The inode must exist already, must support bmap() and
1667 * must have all data blocks preallocated.
1668 */
1669journal_t *jbd2_journal_init_inode(struct inode *inode)
1670{
1671 journal_t *journal;
1672 sector_t blocknr;
1673 int err = 0;
1674
1675 blocknr = 0;
1676 err = bmap(inode, &blocknr);
1677 if (err || !blocknr) {
1678 pr_err("%s: Cannot locate journal superblock\n", __func__);
1679 return err ? ERR_PTR(err) : ERR_PTR(-EINVAL);
1680 }
1681
1682 jbd2_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n",
1683 inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size,
1684 inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
1685
1686 journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev,
1687 blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits,
1688 inode->i_sb->s_blocksize);
1689 if (IS_ERR(journal))
1690 return ERR_CAST(journal);
1691
1692 journal->j_inode = inode;
1693 snprintf(journal->j_devname, sizeof(journal->j_devname),
1694 "%pg-%lu", journal->j_dev, journal->j_inode->i_ino);
1695 strreplace(journal->j_devname, '/', '!');
1696 jbd2_stats_proc_init(journal);
1697
1698 return journal;
1699}
1700
1701/*
1702 * Given a journal_t structure, initialise the various fields for
1703 * startup of a new journaling session. We use this both when creating
1704 * a journal, and after recovering an old journal to reset it for
1705 * subsequent use.
1706 */
1707
1708static int journal_reset(journal_t *journal)
1709{
1710 journal_superblock_t *sb = journal->j_superblock;
1711 unsigned long long first, last;
1712
1713 first = be32_to_cpu(sb->s_first);
1714 last = be32_to_cpu(sb->s_maxlen);
1715 if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
1716 printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
1717 first, last);
1718 journal_fail_superblock(journal);
1719 return -EINVAL;
1720 }
1721
1722 journal->j_first = first;
1723 journal->j_last = last;
1724
1725 if (journal->j_head != 0 && journal->j_flags & JBD2_CYCLE_RECORD) {
1726 /*
1727 * Disable the cycled recording mode if the journal head block
1728 * number is not correct.
1729 */
1730 if (journal->j_head < first || journal->j_head >= last) {
1731 printk(KERN_WARNING "JBD2: Incorrect Journal head block %lu, "
1732 "disable journal_cycle_record\n",
1733 journal->j_head);
1734 journal->j_head = journal->j_first;
1735 }
1736 } else {
1737 journal->j_head = journal->j_first;
1738 }
1739 journal->j_tail = journal->j_head;
1740 journal->j_free = journal->j_last - journal->j_first;
1741
1742 journal->j_tail_sequence = journal->j_transaction_sequence;
1743 journal->j_commit_sequence = journal->j_transaction_sequence - 1;
1744 journal->j_commit_request = journal->j_commit_sequence;
1745
1746 /*
1747 * Now that journal recovery is done, turn fast commits off here. This
1748 * way, if fast commit was enabled before the crash but if now FS has
1749 * disabled it, we don't enable fast commits.
1750 */
1751 jbd2_clear_feature_fast_commit(journal);
1752
1753 /*
1754 * As a special case, if the on-disk copy is already marked as needing
1755 * no recovery (s_start == 0), then we can safely defer the superblock
1756 * update until the next commit by setting JBD2_FLUSHED. This avoids
1757 * attempting a write to a potential-readonly device.
1758 */
1759 if (sb->s_start == 0) {
1760 jbd2_debug(1, "JBD2: Skipping superblock update on recovered sb "
1761 "(start %ld, seq %u, errno %d)\n",
1762 journal->j_tail, journal->j_tail_sequence,
1763 journal->j_errno);
1764 journal->j_flags |= JBD2_FLUSHED;
1765 } else {
1766 /* Lock here to make assertions happy... */
1767 mutex_lock_io(&journal->j_checkpoint_mutex);
1768 /*
1769 * Update log tail information. We use REQ_FUA since new
1770 * transaction will start reusing journal space and so we
1771 * must make sure information about current log tail is on
1772 * disk before that.
1773 */
1774 jbd2_journal_update_sb_log_tail(journal,
1775 journal->j_tail_sequence,
1776 journal->j_tail, REQ_FUA);
1777 mutex_unlock(&journal->j_checkpoint_mutex);
1778 }
1779 return jbd2_journal_start_thread(journal);
1780}
1781
1782/*
1783 * This function expects that the caller will have locked the journal
1784 * buffer head, and will return with it unlocked
1785 */
1786static int jbd2_write_superblock(journal_t *journal, blk_opf_t write_flags)
1787{
1788 struct buffer_head *bh = journal->j_sb_buffer;
1789 journal_superblock_t *sb = journal->j_superblock;
1790 int ret = 0;
1791
1792 /* Buffer got discarded which means block device got invalidated */
1793 if (!buffer_mapped(bh)) {
1794 unlock_buffer(bh);
1795 return -EIO;
1796 }
1797
1798 /*
1799 * Always set high priority flags to exempt from block layer's
1800 * QOS policies, e.g. writeback throttle.
1801 */
1802 write_flags |= JBD2_JOURNAL_REQ_FLAGS;
1803 if (!(journal->j_flags & JBD2_BARRIER))
1804 write_flags &= ~(REQ_FUA | REQ_PREFLUSH);
1805
1806 trace_jbd2_write_superblock(journal, write_flags);
1807
1808 if (buffer_write_io_error(bh)) {
1809 /*
1810 * Oh, dear. A previous attempt to write the journal
1811 * superblock failed. This could happen because the
1812 * USB device was yanked out. Or it could happen to
1813 * be a transient write error and maybe the block will
1814 * be remapped. Nothing we can do but to retry the
1815 * write and hope for the best.
1816 */
1817 printk(KERN_ERR "JBD2: previous I/O error detected "
1818 "for journal superblock update for %s.\n",
1819 journal->j_devname);
1820 clear_buffer_write_io_error(bh);
1821 set_buffer_uptodate(bh);
1822 }
1823 if (jbd2_journal_has_csum_v2or3(journal))
1824 sb->s_checksum = jbd2_superblock_csum(journal, sb);
1825 get_bh(bh);
1826 bh->b_end_io = end_buffer_write_sync;
1827 submit_bh(REQ_OP_WRITE | write_flags, bh);
1828 wait_on_buffer(bh);
1829 if (buffer_write_io_error(bh)) {
1830 clear_buffer_write_io_error(bh);
1831 set_buffer_uptodate(bh);
1832 ret = -EIO;
1833 }
1834 if (ret) {
1835 printk(KERN_ERR "JBD2: I/O error when updating journal superblock for %s.\n",
1836 journal->j_devname);
1837 if (!is_journal_aborted(journal))
1838 jbd2_journal_abort(journal, ret);
1839 }
1840
1841 return ret;
1842}
1843
1844/**
1845 * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
1846 * @journal: The journal to update.
1847 * @tail_tid: TID of the new transaction at the tail of the log
1848 * @tail_block: The first block of the transaction at the tail of the log
1849 * @write_flags: Flags for the journal sb write operation
1850 *
1851 * Update a journal's superblock information about log tail and write it to
1852 * disk, waiting for the IO to complete.
1853 */
1854int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
1855 unsigned long tail_block,
1856 blk_opf_t write_flags)
1857{
1858 journal_superblock_t *sb = journal->j_superblock;
1859 int ret;
1860
1861 if (is_journal_aborted(journal))
1862 return -EIO;
1863 if (jbd2_check_fs_dev_write_error(journal)) {
1864 jbd2_journal_abort(journal, -EIO);
1865 return -EIO;
1866 }
1867
1868 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1869 jbd2_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
1870 tail_block, tail_tid);
1871
1872 lock_buffer(journal->j_sb_buffer);
1873 sb->s_sequence = cpu_to_be32(tail_tid);
1874 sb->s_start = cpu_to_be32(tail_block);
1875
1876 ret = jbd2_write_superblock(journal, write_flags);
1877 if (ret)
1878 goto out;
1879
1880 /* Log is no longer empty */
1881 write_lock(&journal->j_state_lock);
1882 WARN_ON(!sb->s_sequence);
1883 journal->j_flags &= ~JBD2_FLUSHED;
1884 write_unlock(&journal->j_state_lock);
1885
1886out:
1887 return ret;
1888}
1889
1890/**
1891 * jbd2_mark_journal_empty() - Mark on disk journal as empty.
1892 * @journal: The journal to update.
1893 * @write_flags: Flags for the journal sb write operation
1894 *
1895 * Update a journal's dynamic superblock fields to show that journal is empty.
1896 * Write updated superblock to disk waiting for IO to complete.
1897 */
1898static void jbd2_mark_journal_empty(journal_t *journal, blk_opf_t write_flags)
1899{
1900 journal_superblock_t *sb = journal->j_superblock;
1901 bool had_fast_commit = false;
1902
1903 BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
1904 lock_buffer(journal->j_sb_buffer);
1905 if (sb->s_start == 0) { /* Is it already empty? */
1906 unlock_buffer(journal->j_sb_buffer);
1907 return;
1908 }
1909
1910 jbd2_debug(1, "JBD2: Marking journal as empty (seq %u)\n",
1911 journal->j_tail_sequence);
1912
1913 sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
1914 sb->s_start = cpu_to_be32(0);
1915 sb->s_head = cpu_to_be32(journal->j_head);
1916 if (jbd2_has_feature_fast_commit(journal)) {
1917 /*
1918 * When journal is clean, no need to commit fast commit flag and
1919 * make file system incompatible with older kernels.
1920 */
1921 jbd2_clear_feature_fast_commit(journal);
1922 had_fast_commit = true;
1923 }
1924
1925 jbd2_write_superblock(journal, write_flags);
1926
1927 if (had_fast_commit)
1928 jbd2_set_feature_fast_commit(journal);
1929
1930 /* Log is empty */
1931 write_lock(&journal->j_state_lock);
1932 journal->j_flags |= JBD2_FLUSHED;
1933 write_unlock(&journal->j_state_lock);
1934}
1935
1936/**
1937 * __jbd2_journal_erase() - Discard or zeroout journal blocks (excluding superblock)
1938 * @journal: The journal to erase.
1939 * @flags: A discard/zeroout request is sent for each physically contigous
1940 * region of the journal. Either JBD2_JOURNAL_FLUSH_DISCARD or
1941 * JBD2_JOURNAL_FLUSH_ZEROOUT must be set to determine which operation
1942 * to perform.
1943 *
1944 * Note: JBD2_JOURNAL_FLUSH_ZEROOUT attempts to use hardware offload. Zeroes
1945 * will be explicitly written if no hardware offload is available, see
1946 * blkdev_issue_zeroout for more details.
1947 */
1948static int __jbd2_journal_erase(journal_t *journal, unsigned int flags)
1949{
1950 int err = 0;
1951 unsigned long block, log_offset; /* logical */
1952 unsigned long long phys_block, block_start, block_stop; /* physical */
1953 loff_t byte_start, byte_stop, byte_count;
1954
1955 /* flags must be set to either discard or zeroout */
1956 if ((flags & ~JBD2_JOURNAL_FLUSH_VALID) || !flags ||
1957 ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1958 (flags & JBD2_JOURNAL_FLUSH_ZEROOUT)))
1959 return -EINVAL;
1960
1961 if ((flags & JBD2_JOURNAL_FLUSH_DISCARD) &&
1962 !bdev_max_discard_sectors(journal->j_dev))
1963 return -EOPNOTSUPP;
1964
1965 /*
1966 * lookup block mapping and issue discard/zeroout for each
1967 * contiguous region
1968 */
1969 log_offset = be32_to_cpu(journal->j_superblock->s_first);
1970 block_start = ~0ULL;
1971 for (block = log_offset; block < journal->j_total_len; block++) {
1972 err = jbd2_journal_bmap(journal, block, &phys_block);
1973 if (err) {
1974 pr_err("JBD2: bad block at offset %lu", block);
1975 return err;
1976 }
1977
1978 if (block_start == ~0ULL) {
1979 block_start = phys_block;
1980 block_stop = block_start - 1;
1981 }
1982
1983 /*
1984 * last block not contiguous with current block,
1985 * process last contiguous region and return to this block on
1986 * next loop
1987 */
1988 if (phys_block != block_stop + 1) {
1989 block--;
1990 } else {
1991 block_stop++;
1992 /*
1993 * if this isn't the last block of journal,
1994 * no need to process now because next block may also
1995 * be part of this contiguous region
1996 */
1997 if (block != journal->j_total_len - 1)
1998 continue;
1999 }
2000
2001 /*
2002 * end of contiguous region or this is last block of journal,
2003 * take care of the region
2004 */
2005 byte_start = block_start * journal->j_blocksize;
2006 byte_stop = block_stop * journal->j_blocksize;
2007 byte_count = (block_stop - block_start + 1) *
2008 journal->j_blocksize;
2009
2010 truncate_inode_pages_range(journal->j_dev->bd_mapping,
2011 byte_start, byte_stop);
2012
2013 if (flags & JBD2_JOURNAL_FLUSH_DISCARD) {
2014 err = blkdev_issue_discard(journal->j_dev,
2015 byte_start >> SECTOR_SHIFT,
2016 byte_count >> SECTOR_SHIFT,
2017 GFP_NOFS);
2018 } else if (flags & JBD2_JOURNAL_FLUSH_ZEROOUT) {
2019 err = blkdev_issue_zeroout(journal->j_dev,
2020 byte_start >> SECTOR_SHIFT,
2021 byte_count >> SECTOR_SHIFT,
2022 GFP_NOFS, 0);
2023 }
2024
2025 if (unlikely(err != 0)) {
2026 pr_err("JBD2: (error %d) unable to wipe journal at physical blocks %llu - %llu",
2027 err, block_start, block_stop);
2028 return err;
2029 }
2030
2031 /* reset start and stop after processing a region */
2032 block_start = ~0ULL;
2033 }
2034
2035 return blkdev_issue_flush(journal->j_dev);
2036}
2037
2038/**
2039 * jbd2_journal_update_sb_errno() - Update error in the journal.
2040 * @journal: The journal to update.
2041 *
2042 * Update a journal's errno. Write updated superblock to disk waiting for IO
2043 * to complete.
2044 */
2045void jbd2_journal_update_sb_errno(journal_t *journal)
2046{
2047 journal_superblock_t *sb = journal->j_superblock;
2048 int errcode;
2049
2050 lock_buffer(journal->j_sb_buffer);
2051 errcode = journal->j_errno;
2052 if (errcode == -ESHUTDOWN)
2053 errcode = 0;
2054 jbd2_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode);
2055 sb->s_errno = cpu_to_be32(errcode);
2056
2057 jbd2_write_superblock(journal, REQ_FUA);
2058}
2059EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
2060
2061/**
2062 * jbd2_journal_load() - Read journal from disk.
2063 * @journal: Journal to act on.
2064 *
2065 * Given a journal_t structure which tells us which disk blocks contain
2066 * a journal, read the journal from disk to initialise the in-memory
2067 * structures.
2068 */
2069int jbd2_journal_load(journal_t *journal)
2070{
2071 int err;
2072 journal_superblock_t *sb = journal->j_superblock;
2073
2074 /*
2075 * Create a slab for this blocksize
2076 */
2077 err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
2078 if (err)
2079 return err;
2080
2081 /* Let the recovery code check whether it needs to recover any
2082 * data from the journal. */
2083 err = jbd2_journal_recover(journal);
2084 if (err) {
2085 pr_warn("JBD2: journal recovery failed\n");
2086 return err;
2087 }
2088
2089 if (journal->j_failed_commit) {
2090 printk(KERN_ERR "JBD2: journal transaction %u on %s "
2091 "is corrupt.\n", journal->j_failed_commit,
2092 journal->j_devname);
2093 return -EFSCORRUPTED;
2094 }
2095 /*
2096 * clear JBD2_ABORT flag initialized in journal_init_common
2097 * here to update log tail information with the newest seq.
2098 */
2099 journal->j_flags &= ~JBD2_ABORT;
2100
2101 /* OK, we've finished with the dynamic journal bits:
2102 * reinitialise the dynamic contents of the superblock in memory
2103 * and reset them on disk. */
2104 err = journal_reset(journal);
2105 if (err) {
2106 pr_warn("JBD2: journal reset failed\n");
2107 return err;
2108 }
2109
2110 journal->j_flags |= JBD2_LOADED;
2111 return 0;
2112}
2113
2114/**
2115 * jbd2_journal_destroy() - Release a journal_t structure.
2116 * @journal: Journal to act on.
2117 *
2118 * Release a journal_t structure once it is no longer in use by the
2119 * journaled object.
2120 * Return <0 if we couldn't clean up the journal.
2121 */
2122int jbd2_journal_destroy(journal_t *journal)
2123{
2124 int err = 0;
2125
2126 /* Wait for the commit thread to wake up and die. */
2127 journal_kill_thread(journal);
2128
2129 /* Force a final log commit */
2130 if (journal->j_running_transaction)
2131 jbd2_journal_commit_transaction(journal);
2132
2133 /* Force any old transactions to disk */
2134
2135 /* Totally anal locking here... */
2136 spin_lock(&journal->j_list_lock);
2137 while (journal->j_checkpoint_transactions != NULL) {
2138 spin_unlock(&journal->j_list_lock);
2139 mutex_lock_io(&journal->j_checkpoint_mutex);
2140 err = jbd2_log_do_checkpoint(journal);
2141 mutex_unlock(&journal->j_checkpoint_mutex);
2142 /*
2143 * If checkpointing failed, just free the buffers to avoid
2144 * looping forever
2145 */
2146 if (err) {
2147 jbd2_journal_destroy_checkpoint(journal);
2148 spin_lock(&journal->j_list_lock);
2149 break;
2150 }
2151 spin_lock(&journal->j_list_lock);
2152 }
2153
2154 J_ASSERT(journal->j_running_transaction == NULL);
2155 J_ASSERT(journal->j_committing_transaction == NULL);
2156 J_ASSERT(journal->j_checkpoint_transactions == NULL);
2157 spin_unlock(&journal->j_list_lock);
2158
2159 /*
2160 * OK, all checkpoint transactions have been checked, now check the
2161 * writeback errseq of fs dev and abort the journal if some buffer
2162 * failed to write back to the original location, otherwise the
2163 * filesystem may become inconsistent.
2164 */
2165 if (!is_journal_aborted(journal) &&
2166 jbd2_check_fs_dev_write_error(journal))
2167 jbd2_journal_abort(journal, -EIO);
2168
2169 if (journal->j_sb_buffer) {
2170 if (!is_journal_aborted(journal)) {
2171 mutex_lock_io(&journal->j_checkpoint_mutex);
2172
2173 write_lock(&journal->j_state_lock);
2174 journal->j_tail_sequence =
2175 ++journal->j_transaction_sequence;
2176 write_unlock(&journal->j_state_lock);
2177
2178 jbd2_mark_journal_empty(journal, REQ_PREFLUSH | REQ_FUA);
2179 mutex_unlock(&journal->j_checkpoint_mutex);
2180 } else
2181 err = -EIO;
2182 brelse(journal->j_sb_buffer);
2183 }
2184
2185 if (journal->j_shrinker) {
2186 percpu_counter_destroy(&journal->j_checkpoint_jh_count);
2187 shrinker_free(journal->j_shrinker);
2188 }
2189 if (journal->j_proc_entry)
2190 jbd2_stats_proc_exit(journal);
2191 iput(journal->j_inode);
2192 if (journal->j_revoke)
2193 jbd2_journal_destroy_revoke(journal);
2194 if (journal->j_chksum_driver)
2195 crypto_free_shash(journal->j_chksum_driver);
2196 kfree(journal->j_fc_wbuf);
2197 kfree(journal->j_wbuf);
2198 kfree(journal);
2199
2200 return err;
2201}
2202
2203
2204/**
2205 * jbd2_journal_check_used_features() - Check if features specified are used.
2206 * @journal: Journal to check.
2207 * @compat: bitmask of compatible features
2208 * @ro: bitmask of features that force read-only mount
2209 * @incompat: bitmask of incompatible features
2210 *
2211 * Check whether the journal uses all of a given set of
2212 * features. Return true (non-zero) if it does.
2213 **/
2214
2215int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat,
2216 unsigned long ro, unsigned long incompat)
2217{
2218 journal_superblock_t *sb;
2219
2220 if (!compat && !ro && !incompat)
2221 return 1;
2222 if (!jbd2_format_support_feature(journal))
2223 return 0;
2224
2225 sb = journal->j_superblock;
2226
2227 if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
2228 ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
2229 ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
2230 return 1;
2231
2232 return 0;
2233}
2234
2235/**
2236 * jbd2_journal_check_available_features() - Check feature set in journalling layer
2237 * @journal: Journal to check.
2238 * @compat: bitmask of compatible features
2239 * @ro: bitmask of features that force read-only mount
2240 * @incompat: bitmask of incompatible features
2241 *
2242 * Check whether the journaling code supports the use of
2243 * all of a given set of features on this journal. Return true
2244 * (non-zero) if it can. */
2245
2246int jbd2_journal_check_available_features(journal_t *journal, unsigned long compat,
2247 unsigned long ro, unsigned long incompat)
2248{
2249 if (!compat && !ro && !incompat)
2250 return 1;
2251
2252 if (!jbd2_format_support_feature(journal))
2253 return 0;
2254
2255 if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
2256 (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
2257 (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
2258 return 1;
2259
2260 return 0;
2261}
2262
2263static int
2264jbd2_journal_initialize_fast_commit(journal_t *journal)
2265{
2266 journal_superblock_t *sb = journal->j_superblock;
2267 unsigned long long num_fc_blks;
2268
2269 num_fc_blks = jbd2_journal_get_num_fc_blks(sb);
2270 if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS)
2271 return -ENOSPC;
2272
2273 /* Are we called twice? */
2274 WARN_ON(journal->j_fc_wbuf != NULL);
2275 journal->j_fc_wbuf = kmalloc_array(num_fc_blks,
2276 sizeof(struct buffer_head *), GFP_KERNEL);
2277 if (!journal->j_fc_wbuf)
2278 return -ENOMEM;
2279
2280 journal->j_fc_wbufsize = num_fc_blks;
2281 journal->j_fc_last = journal->j_last;
2282 journal->j_last = journal->j_fc_last - num_fc_blks;
2283 journal->j_fc_first = journal->j_last + 1;
2284 journal->j_fc_off = 0;
2285 journal->j_free = journal->j_last - journal->j_first;
2286
2287 return 0;
2288}
2289
2290/**
2291 * jbd2_journal_set_features() - Mark a given journal feature in the superblock
2292 * @journal: Journal to act on.
2293 * @compat: bitmask of compatible features
2294 * @ro: bitmask of features that force read-only mount
2295 * @incompat: bitmask of incompatible features
2296 *
2297 * Mark a given journal feature as present on the
2298 * superblock. Returns true if the requested features could be set.
2299 *
2300 */
2301
2302int jbd2_journal_set_features(journal_t *journal, unsigned long compat,
2303 unsigned long ro, unsigned long incompat)
2304{
2305#define INCOMPAT_FEATURE_ON(f) \
2306 ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
2307#define COMPAT_FEATURE_ON(f) \
2308 ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
2309 journal_superblock_t *sb;
2310
2311 if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
2312 return 1;
2313
2314 if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
2315 return 0;
2316
2317 /* If enabling v2 checksums, turn on v3 instead */
2318 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) {
2319 incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2;
2320 incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3;
2321 }
2322
2323 /* Asking for checksumming v3 and v1? Only give them v3. */
2324 if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 &&
2325 compat & JBD2_FEATURE_COMPAT_CHECKSUM)
2326 compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
2327
2328 jbd2_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
2329 compat, ro, incompat);
2330
2331 sb = journal->j_superblock;
2332
2333 if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) {
2334 if (jbd2_journal_initialize_fast_commit(journal)) {
2335 pr_err("JBD2: Cannot enable fast commits.\n");
2336 return 0;
2337 }
2338 }
2339
2340 /* Load the checksum driver if necessary */
2341 if ((journal->j_chksum_driver == NULL) &&
2342 INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2343 journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
2344 if (IS_ERR(journal->j_chksum_driver)) {
2345 printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n");
2346 journal->j_chksum_driver = NULL;
2347 return 0;
2348 }
2349 /* Precompute checksum seed for all metadata */
2350 journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
2351 sizeof(sb->s_uuid));
2352 }
2353
2354 lock_buffer(journal->j_sb_buffer);
2355
2356 /* If enabling v3 checksums, update superblock */
2357 if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) {
2358 sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
2359 sb->s_feature_compat &=
2360 ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
2361 }
2362
2363 /* If enabling v1 checksums, downgrade superblock */
2364 if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
2365 sb->s_feature_incompat &=
2366 ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 |
2367 JBD2_FEATURE_INCOMPAT_CSUM_V3);
2368
2369 sb->s_feature_compat |= cpu_to_be32(compat);
2370 sb->s_feature_ro_compat |= cpu_to_be32(ro);
2371 sb->s_feature_incompat |= cpu_to_be32(incompat);
2372 unlock_buffer(journal->j_sb_buffer);
2373 jbd2_journal_init_transaction_limits(journal);
2374
2375 return 1;
2376#undef COMPAT_FEATURE_ON
2377#undef INCOMPAT_FEATURE_ON
2378}
2379
2380/*
2381 * jbd2_journal_clear_features() - Clear a given journal feature in the
2382 * superblock
2383 * @journal: Journal to act on.
2384 * @compat: bitmask of compatible features
2385 * @ro: bitmask of features that force read-only mount
2386 * @incompat: bitmask of incompatible features
2387 *
2388 * Clear a given journal feature as present on the
2389 * superblock.
2390 */
2391void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
2392 unsigned long ro, unsigned long incompat)
2393{
2394 journal_superblock_t *sb;
2395
2396 jbd2_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
2397 compat, ro, incompat);
2398
2399 sb = journal->j_superblock;
2400
2401 sb->s_feature_compat &= ~cpu_to_be32(compat);
2402 sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
2403 sb->s_feature_incompat &= ~cpu_to_be32(incompat);
2404 jbd2_journal_init_transaction_limits(journal);
2405}
2406EXPORT_SYMBOL(jbd2_journal_clear_features);
2407
2408/**
2409 * jbd2_journal_flush() - Flush journal
2410 * @journal: Journal to act on.
2411 * @flags: optional operation on the journal blocks after the flush (see below)
2412 *
2413 * Flush all data for a given journal to disk and empty the journal.
2414 * Filesystems can use this when remounting readonly to ensure that
2415 * recovery does not need to happen on remount. Optionally, a discard or zeroout
2416 * can be issued on the journal blocks after flushing.
2417 *
2418 * flags:
2419 * JBD2_JOURNAL_FLUSH_DISCARD: issues discards for the journal blocks
2420 * JBD2_JOURNAL_FLUSH_ZEROOUT: issues zeroouts for the journal blocks
2421 */
2422int jbd2_journal_flush(journal_t *journal, unsigned int flags)
2423{
2424 int err = 0;
2425 transaction_t *transaction = NULL;
2426
2427 write_lock(&journal->j_state_lock);
2428
2429 /* Force everything buffered to the log... */
2430 if (journal->j_running_transaction) {
2431 transaction = journal->j_running_transaction;
2432 __jbd2_log_start_commit(journal, transaction->t_tid);
2433 } else if (journal->j_committing_transaction)
2434 transaction = journal->j_committing_transaction;
2435
2436 /* Wait for the log commit to complete... */
2437 if (transaction) {
2438 tid_t tid = transaction->t_tid;
2439
2440 write_unlock(&journal->j_state_lock);
2441 jbd2_log_wait_commit(journal, tid);
2442 } else {
2443 write_unlock(&journal->j_state_lock);
2444 }
2445
2446 /* ...and flush everything in the log out to disk. */
2447 spin_lock(&journal->j_list_lock);
2448 while (!err && journal->j_checkpoint_transactions != NULL) {
2449 spin_unlock(&journal->j_list_lock);
2450 mutex_lock_io(&journal->j_checkpoint_mutex);
2451 err = jbd2_log_do_checkpoint(journal);
2452 mutex_unlock(&journal->j_checkpoint_mutex);
2453 spin_lock(&journal->j_list_lock);
2454 }
2455 spin_unlock(&journal->j_list_lock);
2456
2457 if (is_journal_aborted(journal))
2458 return -EIO;
2459
2460 mutex_lock_io(&journal->j_checkpoint_mutex);
2461 if (!err) {
2462 err = jbd2_cleanup_journal_tail(journal);
2463 if (err < 0) {
2464 mutex_unlock(&journal->j_checkpoint_mutex);
2465 goto out;
2466 }
2467 err = 0;
2468 }
2469
2470 /* Finally, mark the journal as really needing no recovery.
2471 * This sets s_start==0 in the underlying superblock, which is
2472 * the magic code for a fully-recovered superblock. Any future
2473 * commits of data to the journal will restore the current
2474 * s_start value. */
2475 jbd2_mark_journal_empty(journal, REQ_FUA);
2476
2477 if (flags)
2478 err = __jbd2_journal_erase(journal, flags);
2479
2480 mutex_unlock(&journal->j_checkpoint_mutex);
2481 write_lock(&journal->j_state_lock);
2482 J_ASSERT(!journal->j_running_transaction);
2483 J_ASSERT(!journal->j_committing_transaction);
2484 J_ASSERT(!journal->j_checkpoint_transactions);
2485 J_ASSERT(journal->j_head == journal->j_tail);
2486 J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
2487 write_unlock(&journal->j_state_lock);
2488out:
2489 return err;
2490}
2491
2492/**
2493 * jbd2_journal_wipe() - Wipe journal contents
2494 * @journal: Journal to act on.
2495 * @write: flag (see below)
2496 *
2497 * Wipe out all of the contents of a journal, safely. This will produce
2498 * a warning if the journal contains any valid recovery information.
2499 * Must be called between journal_init_*() and jbd2_journal_load().
2500 *
2501 * If 'write' is non-zero, then we wipe out the journal on disk; otherwise
2502 * we merely suppress recovery.
2503 */
2504
2505int jbd2_journal_wipe(journal_t *journal, int write)
2506{
2507 int err;
2508
2509 J_ASSERT (!(journal->j_flags & JBD2_LOADED));
2510
2511 if (!journal->j_tail)
2512 return 0;
2513
2514 printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
2515 write ? "Clearing" : "Ignoring");
2516
2517 err = jbd2_journal_skip_recovery(journal);
2518 if (write) {
2519 /* Lock to make assertions happy... */
2520 mutex_lock_io(&journal->j_checkpoint_mutex);
2521 jbd2_mark_journal_empty(journal, REQ_FUA);
2522 mutex_unlock(&journal->j_checkpoint_mutex);
2523 }
2524
2525 return err;
2526}
2527
2528/**
2529 * jbd2_journal_abort () - Shutdown the journal immediately.
2530 * @journal: the journal to shutdown.
2531 * @errno: an error number to record in the journal indicating
2532 * the reason for the shutdown.
2533 *
2534 * Perform a complete, immediate shutdown of the ENTIRE
2535 * journal (not of a single transaction). This operation cannot be
2536 * undone without closing and reopening the journal.
2537 *
2538 * The jbd2_journal_abort function is intended to support higher level error
2539 * recovery mechanisms such as the ext2/ext3 remount-readonly error
2540 * mode.
2541 *
2542 * Journal abort has very specific semantics. Any existing dirty,
2543 * unjournaled buffers in the main filesystem will still be written to
2544 * disk by bdflush, but the journaling mechanism will be suspended
2545 * immediately and no further transaction commits will be honoured.
2546 *
2547 * Any dirty, journaled buffers will be written back to disk without
2548 * hitting the journal. Atomicity cannot be guaranteed on an aborted
2549 * filesystem, but we _do_ attempt to leave as much data as possible
2550 * behind for fsck to use for cleanup.
2551 *
2552 * Any attempt to get a new transaction handle on a journal which is in
2553 * ABORT state will just result in an -EROFS error return. A
2554 * jbd2_journal_stop on an existing handle will return -EIO if we have
2555 * entered abort state during the update.
2556 *
2557 * Recursive transactions are not disturbed by journal abort until the
2558 * final jbd2_journal_stop, which will receive the -EIO error.
2559 *
2560 * Finally, the jbd2_journal_abort call allows the caller to supply an errno
2561 * which will be recorded (if possible) in the journal superblock. This
2562 * allows a client to record failure conditions in the middle of a
2563 * transaction without having to complete the transaction to record the
2564 * failure to disk. ext3_error, for example, now uses this
2565 * functionality.
2566 *
2567 */
2568
2569void jbd2_journal_abort(journal_t *journal, int errno)
2570{
2571 transaction_t *transaction;
2572
2573 /*
2574 * Lock the aborting procedure until everything is done, this avoid
2575 * races between filesystem's error handling flow (e.g. ext4_abort()),
2576 * ensure panic after the error info is written into journal's
2577 * superblock.
2578 */
2579 mutex_lock(&journal->j_abort_mutex);
2580 /*
2581 * ESHUTDOWN always takes precedence because a file system check
2582 * caused by any other journal abort error is not required after
2583 * a shutdown triggered.
2584 */
2585 write_lock(&journal->j_state_lock);
2586 if (journal->j_flags & JBD2_ABORT) {
2587 int old_errno = journal->j_errno;
2588
2589 write_unlock(&journal->j_state_lock);
2590 if (old_errno != -ESHUTDOWN && errno == -ESHUTDOWN) {
2591 journal->j_errno = errno;
2592 jbd2_journal_update_sb_errno(journal);
2593 }
2594 mutex_unlock(&journal->j_abort_mutex);
2595 return;
2596 }
2597
2598 /*
2599 * Mark the abort as occurred and start current running transaction
2600 * to release all journaled buffer.
2601 */
2602 pr_err("Aborting journal on device %s.\n", journal->j_devname);
2603
2604 journal->j_flags |= JBD2_ABORT;
2605 journal->j_errno = errno;
2606 transaction = journal->j_running_transaction;
2607 if (transaction)
2608 __jbd2_log_start_commit(journal, transaction->t_tid);
2609 write_unlock(&journal->j_state_lock);
2610
2611 /*
2612 * Record errno to the journal super block, so that fsck and jbd2
2613 * layer could realise that a filesystem check is needed.
2614 */
2615 jbd2_journal_update_sb_errno(journal);
2616 mutex_unlock(&journal->j_abort_mutex);
2617}
2618
2619/**
2620 * jbd2_journal_errno() - returns the journal's error state.
2621 * @journal: journal to examine.
2622 *
2623 * This is the errno number set with jbd2_journal_abort(), the last
2624 * time the journal was mounted - if the journal was stopped
2625 * without calling abort this will be 0.
2626 *
2627 * If the journal has been aborted on this mount time -EROFS will
2628 * be returned.
2629 */
2630int jbd2_journal_errno(journal_t *journal)
2631{
2632 int err;
2633
2634 read_lock(&journal->j_state_lock);
2635 if (journal->j_flags & JBD2_ABORT)
2636 err = -EROFS;
2637 else
2638 err = journal->j_errno;
2639 read_unlock(&journal->j_state_lock);
2640 return err;
2641}
2642
2643/**
2644 * jbd2_journal_clear_err() - clears the journal's error state
2645 * @journal: journal to act on.
2646 *
2647 * An error must be cleared or acked to take a FS out of readonly
2648 * mode.
2649 */
2650int jbd2_journal_clear_err(journal_t *journal)
2651{
2652 int err = 0;
2653
2654 write_lock(&journal->j_state_lock);
2655 if (journal->j_flags & JBD2_ABORT)
2656 err = -EROFS;
2657 else
2658 journal->j_errno = 0;
2659 write_unlock(&journal->j_state_lock);
2660 return err;
2661}
2662
2663/**
2664 * jbd2_journal_ack_err() - Ack journal err.
2665 * @journal: journal to act on.
2666 *
2667 * An error must be cleared or acked to take a FS out of readonly
2668 * mode.
2669 */
2670void jbd2_journal_ack_err(journal_t *journal)
2671{
2672 write_lock(&journal->j_state_lock);
2673 if (journal->j_errno)
2674 journal->j_flags |= JBD2_ACK_ERR;
2675 write_unlock(&journal->j_state_lock);
2676}
2677
2678int jbd2_journal_blocks_per_page(struct inode *inode)
2679{
2680 return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits);
2681}
2682
2683/*
2684 * helper functions to deal with 32 or 64bit block numbers.
2685 */
2686size_t journal_tag_bytes(journal_t *journal)
2687{
2688 size_t sz;
2689
2690 if (jbd2_has_feature_csum3(journal))
2691 return sizeof(journal_block_tag3_t);
2692
2693 sz = sizeof(journal_block_tag_t);
2694
2695 if (jbd2_has_feature_csum2(journal))
2696 sz += sizeof(__u16);
2697
2698 if (jbd2_has_feature_64bit(journal))
2699 return sz;
2700 else
2701 return sz - sizeof(__u32);
2702}
2703
2704/*
2705 * JBD memory management
2706 *
2707 * These functions are used to allocate block-sized chunks of memory
2708 * used for making copies of buffer_head data. Very often it will be
2709 * page-sized chunks of data, but sometimes it will be in
2710 * sub-page-size chunks. (For example, 16k pages on Power systems
2711 * with a 4k block file system.) For blocks smaller than a page, we
2712 * use a SLAB allocator. There are slab caches for each block size,
2713 * which are allocated at mount time, if necessary, and we only free
2714 * (all of) the slab caches when/if the jbd2 module is unloaded. For
2715 * this reason we don't need to a mutex to protect access to
2716 * jbd2_slab[] allocating or releasing memory; only in
2717 * jbd2_journal_create_slab().
2718 */
2719#define JBD2_MAX_SLABS 8
2720static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
2721
2722static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
2723 "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
2724 "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
2725};
2726
2727
2728static void jbd2_journal_destroy_slabs(void)
2729{
2730 int i;
2731
2732 for (i = 0; i < JBD2_MAX_SLABS; i++) {
2733 kmem_cache_destroy(jbd2_slab[i]);
2734 jbd2_slab[i] = NULL;
2735 }
2736}
2737
2738static int jbd2_journal_create_slab(size_t size)
2739{
2740 static DEFINE_MUTEX(jbd2_slab_create_mutex);
2741 int i = order_base_2(size) - 10;
2742 size_t slab_size;
2743
2744 if (size == PAGE_SIZE)
2745 return 0;
2746
2747 if (i >= JBD2_MAX_SLABS)
2748 return -EINVAL;
2749
2750 if (unlikely(i < 0))
2751 i = 0;
2752 mutex_lock(&jbd2_slab_create_mutex);
2753 if (jbd2_slab[i]) {
2754 mutex_unlock(&jbd2_slab_create_mutex);
2755 return 0; /* Already created */
2756 }
2757
2758 slab_size = 1 << (i+10);
2759 jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
2760 slab_size, 0, NULL);
2761 mutex_unlock(&jbd2_slab_create_mutex);
2762 if (!jbd2_slab[i]) {
2763 printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
2764 return -ENOMEM;
2765 }
2766 return 0;
2767}
2768
2769static struct kmem_cache *get_slab(size_t size)
2770{
2771 int i = order_base_2(size) - 10;
2772
2773 BUG_ON(i >= JBD2_MAX_SLABS);
2774 if (unlikely(i < 0))
2775 i = 0;
2776 BUG_ON(jbd2_slab[i] == NULL);
2777 return jbd2_slab[i];
2778}
2779
2780void *jbd2_alloc(size_t size, gfp_t flags)
2781{
2782 void *ptr;
2783
2784 BUG_ON(size & (size-1)); /* Must be a power of 2 */
2785
2786 if (size < PAGE_SIZE)
2787 ptr = kmem_cache_alloc(get_slab(size), flags);
2788 else
2789 ptr = (void *)__get_free_pages(flags, get_order(size));
2790
2791 /* Check alignment; SLUB has gotten this wrong in the past,
2792 * and this can lead to user data corruption! */
2793 BUG_ON(((unsigned long) ptr) & (size-1));
2794
2795 return ptr;
2796}
2797
2798void jbd2_free(void *ptr, size_t size)
2799{
2800 if (size < PAGE_SIZE)
2801 kmem_cache_free(get_slab(size), ptr);
2802 else
2803 free_pages((unsigned long)ptr, get_order(size));
2804};
2805
2806/*
2807 * Journal_head storage management
2808 */
2809static struct kmem_cache *jbd2_journal_head_cache;
2810#ifdef CONFIG_JBD2_DEBUG
2811static atomic_t nr_journal_heads = ATOMIC_INIT(0);
2812#endif
2813
2814static int __init jbd2_journal_init_journal_head_cache(void)
2815{
2816 J_ASSERT(!jbd2_journal_head_cache);
2817 jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
2818 sizeof(struct journal_head),
2819 0, /* offset */
2820 SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU,
2821 NULL); /* ctor */
2822 if (!jbd2_journal_head_cache) {
2823 printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
2824 return -ENOMEM;
2825 }
2826 return 0;
2827}
2828
2829static void jbd2_journal_destroy_journal_head_cache(void)
2830{
2831 kmem_cache_destroy(jbd2_journal_head_cache);
2832 jbd2_journal_head_cache = NULL;
2833}
2834
2835/*
2836 * journal_head splicing and dicing
2837 */
2838static struct journal_head *journal_alloc_journal_head(void)
2839{
2840 struct journal_head *ret;
2841
2842#ifdef CONFIG_JBD2_DEBUG
2843 atomic_inc(&nr_journal_heads);
2844#endif
2845 ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
2846 if (!ret) {
2847 jbd2_debug(1, "out of memory for journal_head\n");
2848 pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
2849 ret = kmem_cache_zalloc(jbd2_journal_head_cache,
2850 GFP_NOFS | __GFP_NOFAIL);
2851 }
2852 spin_lock_init(&ret->b_state_lock);
2853 return ret;
2854}
2855
2856static void journal_free_journal_head(struct journal_head *jh)
2857{
2858#ifdef CONFIG_JBD2_DEBUG
2859 atomic_dec(&nr_journal_heads);
2860 memset(jh, JBD2_POISON_FREE, sizeof(*jh));
2861#endif
2862 kmem_cache_free(jbd2_journal_head_cache, jh);
2863}
2864
2865/*
2866 * A journal_head is attached to a buffer_head whenever JBD has an
2867 * interest in the buffer.
2868 *
2869 * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
2870 * is set. This bit is tested in core kernel code where we need to take
2871 * JBD-specific actions. Testing the zeroness of ->b_private is not reliable
2872 * there.
2873 *
2874 * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
2875 *
2876 * When a buffer has its BH_JBD bit set it is immune from being released by
2877 * core kernel code, mainly via ->b_count.
2878 *
2879 * A journal_head is detached from its buffer_head when the journal_head's
2880 * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
2881 * transaction (b_cp_transaction) hold their references to b_jcount.
2882 *
2883 * Various places in the kernel want to attach a journal_head to a buffer_head
2884 * _before_ attaching the journal_head to a transaction. To protect the
2885 * journal_head in this situation, jbd2_journal_add_journal_head elevates the
2886 * journal_head's b_jcount refcount by one. The caller must call
2887 * jbd2_journal_put_journal_head() to undo this.
2888 *
2889 * So the typical usage would be:
2890 *
2891 * (Attach a journal_head if needed. Increments b_jcount)
2892 * struct journal_head *jh = jbd2_journal_add_journal_head(bh);
2893 * ...
2894 * (Get another reference for transaction)
2895 * jbd2_journal_grab_journal_head(bh);
2896 * jh->b_transaction = xxx;
2897 * (Put original reference)
2898 * jbd2_journal_put_journal_head(jh);
2899 */
2900
2901/*
2902 * Give a buffer_head a journal_head.
2903 *
2904 * May sleep.
2905 */
2906struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
2907{
2908 struct journal_head *jh;
2909 struct journal_head *new_jh = NULL;
2910
2911repeat:
2912 if (!buffer_jbd(bh))
2913 new_jh = journal_alloc_journal_head();
2914
2915 jbd_lock_bh_journal_head(bh);
2916 if (buffer_jbd(bh)) {
2917 jh = bh2jh(bh);
2918 } else {
2919 J_ASSERT_BH(bh,
2920 (atomic_read(&bh->b_count) > 0) ||
2921 (bh->b_folio && bh->b_folio->mapping));
2922
2923 if (!new_jh) {
2924 jbd_unlock_bh_journal_head(bh);
2925 goto repeat;
2926 }
2927
2928 jh = new_jh;
2929 new_jh = NULL; /* We consumed it */
2930 set_buffer_jbd(bh);
2931 bh->b_private = jh;
2932 jh->b_bh = bh;
2933 get_bh(bh);
2934 BUFFER_TRACE(bh, "added journal_head");
2935 }
2936 jh->b_jcount++;
2937 jbd_unlock_bh_journal_head(bh);
2938 if (new_jh)
2939 journal_free_journal_head(new_jh);
2940 return bh->b_private;
2941}
2942
2943/*
2944 * Grab a ref against this buffer_head's journal_head. If it ended up not
2945 * having a journal_head, return NULL
2946 */
2947struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
2948{
2949 struct journal_head *jh = NULL;
2950
2951 jbd_lock_bh_journal_head(bh);
2952 if (buffer_jbd(bh)) {
2953 jh = bh2jh(bh);
2954 jh->b_jcount++;
2955 }
2956 jbd_unlock_bh_journal_head(bh);
2957 return jh;
2958}
2959EXPORT_SYMBOL(jbd2_journal_grab_journal_head);
2960
2961static void __journal_remove_journal_head(struct buffer_head *bh)
2962{
2963 struct journal_head *jh = bh2jh(bh);
2964
2965 J_ASSERT_JH(jh, jh->b_transaction == NULL);
2966 J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
2967 J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
2968 J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
2969 J_ASSERT_BH(bh, buffer_jbd(bh));
2970 J_ASSERT_BH(bh, jh2bh(jh) == bh);
2971 BUFFER_TRACE(bh, "remove journal_head");
2972
2973 /* Unlink before dropping the lock */
2974 bh->b_private = NULL;
2975 jh->b_bh = NULL; /* debug, really */
2976 clear_buffer_jbd(bh);
2977}
2978
2979static void journal_release_journal_head(struct journal_head *jh, size_t b_size)
2980{
2981 if (jh->b_frozen_data) {
2982 printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
2983 jbd2_free(jh->b_frozen_data, b_size);
2984 }
2985 if (jh->b_committed_data) {
2986 printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
2987 jbd2_free(jh->b_committed_data, b_size);
2988 }
2989 journal_free_journal_head(jh);
2990}
2991
2992/*
2993 * Drop a reference on the passed journal_head. If it fell to zero then
2994 * release the journal_head from the buffer_head.
2995 */
2996void jbd2_journal_put_journal_head(struct journal_head *jh)
2997{
2998 struct buffer_head *bh = jh2bh(jh);
2999
3000 jbd_lock_bh_journal_head(bh);
3001 J_ASSERT_JH(jh, jh->b_jcount > 0);
3002 --jh->b_jcount;
3003 if (!jh->b_jcount) {
3004 __journal_remove_journal_head(bh);
3005 jbd_unlock_bh_journal_head(bh);
3006 journal_release_journal_head(jh, bh->b_size);
3007 __brelse(bh);
3008 } else {
3009 jbd_unlock_bh_journal_head(bh);
3010 }
3011}
3012EXPORT_SYMBOL(jbd2_journal_put_journal_head);
3013
3014/*
3015 * Initialize jbd inode head
3016 */
3017void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
3018{
3019 jinode->i_transaction = NULL;
3020 jinode->i_next_transaction = NULL;
3021 jinode->i_vfs_inode = inode;
3022 jinode->i_flags = 0;
3023 jinode->i_dirty_start = 0;
3024 jinode->i_dirty_end = 0;
3025 INIT_LIST_HEAD(&jinode->i_list);
3026}
3027
3028/*
3029 * Function to be called before we start removing inode from memory (i.e.,
3030 * clear_inode() is a fine place to be called from). It removes inode from
3031 * transaction's lists.
3032 */
3033void jbd2_journal_release_jbd_inode(journal_t *journal,
3034 struct jbd2_inode *jinode)
3035{
3036 if (!journal)
3037 return;
3038restart:
3039 spin_lock(&journal->j_list_lock);
3040 /* Is commit writing out inode - we have to wait */
3041 if (jinode->i_flags & JI_COMMIT_RUNNING) {
3042 wait_queue_head_t *wq;
3043 DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
3044 wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
3045 prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
3046 spin_unlock(&journal->j_list_lock);
3047 schedule();
3048 finish_wait(wq, &wait.wq_entry);
3049 goto restart;
3050 }
3051
3052 if (jinode->i_transaction) {
3053 list_del(&jinode->i_list);
3054 jinode->i_transaction = NULL;
3055 }
3056 spin_unlock(&journal->j_list_lock);
3057}
3058
3059
3060#ifdef CONFIG_PROC_FS
3061
3062#define JBD2_STATS_PROC_NAME "fs/jbd2"
3063
3064static void __init jbd2_create_jbd_stats_proc_entry(void)
3065{
3066 proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
3067}
3068
3069static void __exit jbd2_remove_jbd_stats_proc_entry(void)
3070{
3071 if (proc_jbd2_stats)
3072 remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
3073}
3074
3075#else
3076
3077#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
3078#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
3079
3080#endif
3081
3082struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
3083
3084static int __init jbd2_journal_init_inode_cache(void)
3085{
3086 J_ASSERT(!jbd2_inode_cache);
3087 jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
3088 if (!jbd2_inode_cache) {
3089 pr_emerg("JBD2: failed to create inode cache\n");
3090 return -ENOMEM;
3091 }
3092 return 0;
3093}
3094
3095static int __init jbd2_journal_init_handle_cache(void)
3096{
3097 J_ASSERT(!jbd2_handle_cache);
3098 jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
3099 if (!jbd2_handle_cache) {
3100 printk(KERN_EMERG "JBD2: failed to create handle cache\n");
3101 return -ENOMEM;
3102 }
3103 return 0;
3104}
3105
3106static void jbd2_journal_destroy_inode_cache(void)
3107{
3108 kmem_cache_destroy(jbd2_inode_cache);
3109 jbd2_inode_cache = NULL;
3110}
3111
3112static void jbd2_journal_destroy_handle_cache(void)
3113{
3114 kmem_cache_destroy(jbd2_handle_cache);
3115 jbd2_handle_cache = NULL;
3116}
3117
3118/*
3119 * Module startup and shutdown
3120 */
3121
3122static int __init journal_init_caches(void)
3123{
3124 int ret;
3125
3126 ret = jbd2_journal_init_revoke_record_cache();
3127 if (ret == 0)
3128 ret = jbd2_journal_init_revoke_table_cache();
3129 if (ret == 0)
3130 ret = jbd2_journal_init_journal_head_cache();
3131 if (ret == 0)
3132 ret = jbd2_journal_init_handle_cache();
3133 if (ret == 0)
3134 ret = jbd2_journal_init_inode_cache();
3135 if (ret == 0)
3136 ret = jbd2_journal_init_transaction_cache();
3137 return ret;
3138}
3139
3140static void jbd2_journal_destroy_caches(void)
3141{
3142 jbd2_journal_destroy_revoke_record_cache();
3143 jbd2_journal_destroy_revoke_table_cache();
3144 jbd2_journal_destroy_journal_head_cache();
3145 jbd2_journal_destroy_handle_cache();
3146 jbd2_journal_destroy_inode_cache();
3147 jbd2_journal_destroy_transaction_cache();
3148 jbd2_journal_destroy_slabs();
3149}
3150
3151static int __init journal_init(void)
3152{
3153 int ret;
3154
3155 BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
3156
3157 ret = journal_init_caches();
3158 if (ret == 0) {
3159 jbd2_create_jbd_stats_proc_entry();
3160 } else {
3161 jbd2_journal_destroy_caches();
3162 }
3163 return ret;
3164}
3165
3166static void __exit journal_exit(void)
3167{
3168#ifdef CONFIG_JBD2_DEBUG
3169 int n = atomic_read(&nr_journal_heads);
3170 if (n)
3171 printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n);
3172#endif
3173 jbd2_remove_jbd_stats_proc_entry();
3174 jbd2_journal_destroy_caches();
3175}
3176
3177MODULE_DESCRIPTION("Generic filesystem journal-writing module");
3178MODULE_LICENSE("GPL");
3179module_init(journal_init);
3180module_exit(journal_exit);
3181