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