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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct page *page;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 page = bh->b_page;
72 if (!page)
73 goto nope;
74 if (page->mapping)
75 goto nope;
76
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
79 goto nope;
80
81 get_page(page);
82 __brelse(bh);
83 try_to_free_buffers(page);
84 unlock_page(page);
85 put_page(page);
86 return;
87
88nope:
89 __brelse(bh);
90}
91
92static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
93{
94 struct commit_header *h;
95 __u32 csum;
96
97 if (!jbd2_journal_has_csum_v2or3(j))
98 return;
99
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 0;
103 h->h_chksum[0] = 0;
104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
105 h->h_chksum[0] = cpu_to_be32(csum);
106}
107
108/*
109 * Done it all: now submit the commit record. We should have
110 * cleaned up our previous buffers by now, so if we are in abort
111 * mode we can now just skip the rest of the journal write
112 * entirely.
113 *
114 * Returns 1 if the journal needs to be aborted or 0 on success
115 */
116static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
119 __u32 crc32_sum)
120{
121 struct commit_header *tmp;
122 struct buffer_head *bh;
123 int ret;
124 struct timespec64 now;
125
126 *cbh = NULL;
127
128 if (is_journal_aborted(journal))
129 return 0;
130
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
132 JBD2_COMMIT_BLOCK);
133 if (!bh)
134 return 1;
135
136 tmp = (struct commit_header *)bh->b_data;
137 ktime_get_coarse_real_ts64(&now);
138 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
139 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
140
141 if (jbd2_has_feature_checksum(journal)) {
142 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
143 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
144 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
145 }
146 jbd2_commit_block_csum_set(journal, bh);
147
148 BUFFER_TRACE(bh, "submit commit block");
149 lock_buffer(bh);
150 clear_buffer_dirty(bh);
151 set_buffer_uptodate(bh);
152 bh->b_end_io = journal_end_buffer_io_sync;
153
154 if (journal->j_flags & JBD2_BARRIER &&
155 !jbd2_has_feature_async_commit(journal))
156 ret = submit_bh(REQ_OP_WRITE,
157 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
158 else
159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
160
161 *cbh = bh;
162 return ret;
163}
164
165/*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
169static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171{
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182}
183
184/*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
190static int journal_submit_inode_data_buffers(struct address_space *mapping,
191 loff_t dirty_start, loff_t dirty_end)
192{
193 int ret;
194 struct writeback_control wbc = {
195 .sync_mode = WB_SYNC_ALL,
196 .nr_to_write = mapping->nrpages * 2,
197 .range_start = dirty_start,
198 .range_end = dirty_end,
199 };
200
201 ret = generic_writepages(mapping, &wbc);
202 return ret;
203}
204
205/*
206 * Submit all the data buffers of inode associated with the transaction to
207 * disk.
208 *
209 * We are in a committing transaction. Therefore no new inode can be added to
210 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
211 * operate on from being released while we write out pages.
212 */
213static int journal_submit_data_buffers(journal_t *journal,
214 transaction_t *commit_transaction)
215{
216 struct jbd2_inode *jinode;
217 int err, ret = 0;
218 struct address_space *mapping;
219
220 spin_lock(&journal->j_list_lock);
221 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
222 loff_t dirty_start = jinode->i_dirty_start;
223 loff_t dirty_end = jinode->i_dirty_end;
224
225 if (!(jinode->i_flags & JI_WRITE_DATA))
226 continue;
227 mapping = jinode->i_vfs_inode->i_mapping;
228 jinode->i_flags |= JI_COMMIT_RUNNING;
229 spin_unlock(&journal->j_list_lock);
230 /*
231 * submit the inode data buffers. We use writepage
232 * instead of writepages. Because writepages can do
233 * block allocation with delalloc. We need to write
234 * only allocated blocks here.
235 */
236 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
237 err = journal_submit_inode_data_buffers(mapping, dirty_start,
238 dirty_end);
239 if (!ret)
240 ret = err;
241 spin_lock(&journal->j_list_lock);
242 J_ASSERT(jinode->i_transaction == commit_transaction);
243 jinode->i_flags &= ~JI_COMMIT_RUNNING;
244 smp_mb();
245 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
246 }
247 spin_unlock(&journal->j_list_lock);
248 return ret;
249}
250
251/*
252 * Wait for data submitted for writeout, refile inodes to proper
253 * transaction if needed.
254 *
255 */
256static int journal_finish_inode_data_buffers(journal_t *journal,
257 transaction_t *commit_transaction)
258{
259 struct jbd2_inode *jinode, *next_i;
260 int err, ret = 0;
261
262 /* For locking, see the comment in journal_submit_data_buffers() */
263 spin_lock(&journal->j_list_lock);
264 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
265 loff_t dirty_start = jinode->i_dirty_start;
266 loff_t dirty_end = jinode->i_dirty_end;
267
268 if (!(jinode->i_flags & JI_WAIT_DATA))
269 continue;
270 jinode->i_flags |= JI_COMMIT_RUNNING;
271 spin_unlock(&journal->j_list_lock);
272 err = filemap_fdatawait_range_keep_errors(
273 jinode->i_vfs_inode->i_mapping, dirty_start,
274 dirty_end);
275 if (!ret)
276 ret = err;
277 spin_lock(&journal->j_list_lock);
278 jinode->i_flags &= ~JI_COMMIT_RUNNING;
279 smp_mb();
280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
281 }
282
283 /* Now refile inode to proper lists */
284 list_for_each_entry_safe(jinode, next_i,
285 &commit_transaction->t_inode_list, i_list) {
286 list_del(&jinode->i_list);
287 if (jinode->i_next_transaction) {
288 jinode->i_transaction = jinode->i_next_transaction;
289 jinode->i_next_transaction = NULL;
290 list_add(&jinode->i_list,
291 &jinode->i_transaction->t_inode_list);
292 } else {
293 jinode->i_transaction = NULL;
294 jinode->i_dirty_start = 0;
295 jinode->i_dirty_end = 0;
296 }
297 }
298 spin_unlock(&journal->j_list_lock);
299
300 return ret;
301}
302
303static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
304{
305 struct page *page = bh->b_page;
306 char *addr;
307 __u32 checksum;
308
309 addr = kmap_atomic(page);
310 checksum = crc32_be(crc32_sum,
311 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
312 kunmap_atomic(addr);
313
314 return checksum;
315}
316
317static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
318 unsigned long long block)
319{
320 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
321 if (jbd2_has_feature_64bit(j))
322 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
323}
324
325static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
326 struct buffer_head *bh, __u32 sequence)
327{
328 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
329 struct page *page = bh->b_page;
330 __u8 *addr;
331 __u32 csum32;
332 __be32 seq;
333
334 if (!jbd2_journal_has_csum_v2or3(j))
335 return;
336
337 seq = cpu_to_be32(sequence);
338 addr = kmap_atomic(page);
339 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
340 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
341 bh->b_size);
342 kunmap_atomic(addr);
343
344 if (jbd2_has_feature_csum3(j))
345 tag3->t_checksum = cpu_to_be32(csum32);
346 else
347 tag->t_checksum = cpu_to_be16(csum32);
348}
349/*
350 * jbd2_journal_commit_transaction
351 *
352 * The primary function for committing a transaction to the log. This
353 * function is called by the journal thread to begin a complete commit.
354 */
355void jbd2_journal_commit_transaction(journal_t *journal)
356{
357 struct transaction_stats_s stats;
358 transaction_t *commit_transaction;
359 struct journal_head *jh;
360 struct buffer_head *descriptor;
361 struct buffer_head **wbuf = journal->j_wbuf;
362 int bufs;
363 int flags;
364 int err;
365 unsigned long long blocknr;
366 ktime_t start_time;
367 u64 commit_time;
368 char *tagp = NULL;
369 journal_block_tag_t *tag = NULL;
370 int space_left = 0;
371 int first_tag = 0;
372 int tag_flag;
373 int i;
374 int tag_bytes = journal_tag_bytes(journal);
375 struct buffer_head *cbh = NULL; /* For transactional checksums */
376 __u32 crc32_sum = ~0;
377 struct blk_plug plug;
378 /* Tail of the journal */
379 unsigned long first_block;
380 tid_t first_tid;
381 int update_tail;
382 int csum_size = 0;
383 LIST_HEAD(io_bufs);
384 LIST_HEAD(log_bufs);
385
386 if (jbd2_journal_has_csum_v2or3(journal))
387 csum_size = sizeof(struct jbd2_journal_block_tail);
388
389 /*
390 * First job: lock down the current transaction and wait for
391 * all outstanding updates to complete.
392 */
393
394 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
395 if (journal->j_flags & JBD2_FLUSHED) {
396 jbd_debug(3, "super block updated\n");
397 mutex_lock_io(&journal->j_checkpoint_mutex);
398 /*
399 * We hold j_checkpoint_mutex so tail cannot change under us.
400 * We don't need any special data guarantees for writing sb
401 * since journal is empty and it is ok for write to be
402 * flushed only with transaction commit.
403 */
404 jbd2_journal_update_sb_log_tail(journal,
405 journal->j_tail_sequence,
406 journal->j_tail,
407 REQ_SYNC);
408 mutex_unlock(&journal->j_checkpoint_mutex);
409 } else {
410 jbd_debug(3, "superblock not updated\n");
411 }
412
413 J_ASSERT(journal->j_running_transaction != NULL);
414 J_ASSERT(journal->j_committing_transaction == NULL);
415
416 commit_transaction = journal->j_running_transaction;
417
418 trace_jbd2_start_commit(journal, commit_transaction);
419 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
420 commit_transaction->t_tid);
421
422 write_lock(&journal->j_state_lock);
423 J_ASSERT(commit_transaction->t_state == T_RUNNING);
424 commit_transaction->t_state = T_LOCKED;
425
426 trace_jbd2_commit_locking(journal, commit_transaction);
427 stats.run.rs_wait = commit_transaction->t_max_wait;
428 stats.run.rs_request_delay = 0;
429 stats.run.rs_locked = jiffies;
430 if (commit_transaction->t_requested)
431 stats.run.rs_request_delay =
432 jbd2_time_diff(commit_transaction->t_requested,
433 stats.run.rs_locked);
434 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
435 stats.run.rs_locked);
436
437 spin_lock(&commit_transaction->t_handle_lock);
438 while (atomic_read(&commit_transaction->t_updates)) {
439 DEFINE_WAIT(wait);
440
441 prepare_to_wait(&journal->j_wait_updates, &wait,
442 TASK_UNINTERRUPTIBLE);
443 if (atomic_read(&commit_transaction->t_updates)) {
444 spin_unlock(&commit_transaction->t_handle_lock);
445 write_unlock(&journal->j_state_lock);
446 schedule();
447 write_lock(&journal->j_state_lock);
448 spin_lock(&commit_transaction->t_handle_lock);
449 }
450 finish_wait(&journal->j_wait_updates, &wait);
451 }
452 spin_unlock(&commit_transaction->t_handle_lock);
453 commit_transaction->t_state = T_SWITCH;
454 write_unlock(&journal->j_state_lock);
455
456 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
457 journal->j_max_transaction_buffers);
458
459 /*
460 * First thing we are allowed to do is to discard any remaining
461 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
462 * that there are no such buffers: if a large filesystem
463 * operation like a truncate needs to split itself over multiple
464 * transactions, then it may try to do a jbd2_journal_restart() while
465 * there are still BJ_Reserved buffers outstanding. These must
466 * be released cleanly from the current transaction.
467 *
468 * In this case, the filesystem must still reserve write access
469 * again before modifying the buffer in the new transaction, but
470 * we do not require it to remember exactly which old buffers it
471 * has reserved. This is consistent with the existing behaviour
472 * that multiple jbd2_journal_get_write_access() calls to the same
473 * buffer are perfectly permissible.
474 */
475 while (commit_transaction->t_reserved_list) {
476 jh = commit_transaction->t_reserved_list;
477 JBUFFER_TRACE(jh, "reserved, unused: refile");
478 /*
479 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
480 * leave undo-committed data.
481 */
482 if (jh->b_committed_data) {
483 struct buffer_head *bh = jh2bh(jh);
484
485 spin_lock(&jh->b_state_lock);
486 jbd2_free(jh->b_committed_data, bh->b_size);
487 jh->b_committed_data = NULL;
488 spin_unlock(&jh->b_state_lock);
489 }
490 jbd2_journal_refile_buffer(journal, jh);
491 }
492
493 /*
494 * Now try to drop any written-back buffers from the journal's
495 * checkpoint lists. We do this *before* commit because it potentially
496 * frees some memory
497 */
498 spin_lock(&journal->j_list_lock);
499 __jbd2_journal_clean_checkpoint_list(journal, false);
500 spin_unlock(&journal->j_list_lock);
501
502 jbd_debug(3, "JBD2: commit phase 1\n");
503
504 /*
505 * Clear revoked flag to reflect there is no revoked buffers
506 * in the next transaction which is going to be started.
507 */
508 jbd2_clear_buffer_revoked_flags(journal);
509
510 /*
511 * Switch to a new revoke table.
512 */
513 jbd2_journal_switch_revoke_table(journal);
514
515 /*
516 * Reserved credits cannot be claimed anymore, free them
517 */
518 atomic_sub(atomic_read(&journal->j_reserved_credits),
519 &commit_transaction->t_outstanding_credits);
520
521 write_lock(&journal->j_state_lock);
522 trace_jbd2_commit_flushing(journal, commit_transaction);
523 stats.run.rs_flushing = jiffies;
524 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
525 stats.run.rs_flushing);
526
527 commit_transaction->t_state = T_FLUSH;
528 journal->j_committing_transaction = commit_transaction;
529 journal->j_running_transaction = NULL;
530 start_time = ktime_get();
531 commit_transaction->t_log_start = journal->j_head;
532 wake_up(&journal->j_wait_transaction_locked);
533 write_unlock(&journal->j_state_lock);
534
535 jbd_debug(3, "JBD2: commit phase 2a\n");
536
537 /*
538 * Now start flushing things to disk, in the order they appear
539 * on the transaction lists. Data blocks go first.
540 */
541 err = journal_submit_data_buffers(journal, commit_transaction);
542 if (err)
543 jbd2_journal_abort(journal, err);
544
545 blk_start_plug(&plug);
546 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
547
548 jbd_debug(3, "JBD2: commit phase 2b\n");
549
550 /*
551 * Way to go: we have now written out all of the data for a
552 * transaction! Now comes the tricky part: we need to write out
553 * metadata. Loop over the transaction's entire buffer list:
554 */
555 write_lock(&journal->j_state_lock);
556 commit_transaction->t_state = T_COMMIT;
557 write_unlock(&journal->j_state_lock);
558
559 trace_jbd2_commit_logging(journal, commit_transaction);
560 stats.run.rs_logging = jiffies;
561 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
562 stats.run.rs_logging);
563 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
564 stats.run.rs_blocks_logged = 0;
565
566 J_ASSERT(commit_transaction->t_nr_buffers <=
567 atomic_read(&commit_transaction->t_outstanding_credits));
568
569 err = 0;
570 bufs = 0;
571 descriptor = NULL;
572 while (commit_transaction->t_buffers) {
573
574 /* Find the next buffer to be journaled... */
575
576 jh = commit_transaction->t_buffers;
577
578 /* If we're in abort mode, we just un-journal the buffer and
579 release it. */
580
581 if (is_journal_aborted(journal)) {
582 clear_buffer_jbddirty(jh2bh(jh));
583 JBUFFER_TRACE(jh, "journal is aborting: refile");
584 jbd2_buffer_abort_trigger(jh,
585 jh->b_frozen_data ?
586 jh->b_frozen_triggers :
587 jh->b_triggers);
588 jbd2_journal_refile_buffer(journal, jh);
589 /* If that was the last one, we need to clean up
590 * any descriptor buffers which may have been
591 * already allocated, even if we are now
592 * aborting. */
593 if (!commit_transaction->t_buffers)
594 goto start_journal_io;
595 continue;
596 }
597
598 /* Make sure we have a descriptor block in which to
599 record the metadata buffer. */
600
601 if (!descriptor) {
602 J_ASSERT (bufs == 0);
603
604 jbd_debug(4, "JBD2: get descriptor\n");
605
606 descriptor = jbd2_journal_get_descriptor_buffer(
607 commit_transaction,
608 JBD2_DESCRIPTOR_BLOCK);
609 if (!descriptor) {
610 jbd2_journal_abort(journal, -EIO);
611 continue;
612 }
613
614 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
615 (unsigned long long)descriptor->b_blocknr,
616 descriptor->b_data);
617 tagp = &descriptor->b_data[sizeof(journal_header_t)];
618 space_left = descriptor->b_size -
619 sizeof(journal_header_t);
620 first_tag = 1;
621 set_buffer_jwrite(descriptor);
622 set_buffer_dirty(descriptor);
623 wbuf[bufs++] = descriptor;
624
625 /* Record it so that we can wait for IO
626 completion later */
627 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
628 jbd2_file_log_bh(&log_bufs, descriptor);
629 }
630
631 /* Where is the buffer to be written? */
632
633 err = jbd2_journal_next_log_block(journal, &blocknr);
634 /* If the block mapping failed, just abandon the buffer
635 and repeat this loop: we'll fall into the
636 refile-on-abort condition above. */
637 if (err) {
638 jbd2_journal_abort(journal, err);
639 continue;
640 }
641
642 /*
643 * start_this_handle() uses t_outstanding_credits to determine
644 * the free space in the log.
645 */
646 atomic_dec(&commit_transaction->t_outstanding_credits);
647
648 /* Bump b_count to prevent truncate from stumbling over
649 the shadowed buffer! @@@ This can go if we ever get
650 rid of the shadow pairing of buffers. */
651 atomic_inc(&jh2bh(jh)->b_count);
652
653 /*
654 * Make a temporary IO buffer with which to write it out
655 * (this will requeue the metadata buffer to BJ_Shadow).
656 */
657 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
658 JBUFFER_TRACE(jh, "ph3: write metadata");
659 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
660 jh, &wbuf[bufs], blocknr);
661 if (flags < 0) {
662 jbd2_journal_abort(journal, flags);
663 continue;
664 }
665 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
666
667 /* Record the new block's tag in the current descriptor
668 buffer */
669
670 tag_flag = 0;
671 if (flags & 1)
672 tag_flag |= JBD2_FLAG_ESCAPE;
673 if (!first_tag)
674 tag_flag |= JBD2_FLAG_SAME_UUID;
675
676 tag = (journal_block_tag_t *) tagp;
677 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
678 tag->t_flags = cpu_to_be16(tag_flag);
679 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
680 commit_transaction->t_tid);
681 tagp += tag_bytes;
682 space_left -= tag_bytes;
683 bufs++;
684
685 if (first_tag) {
686 memcpy (tagp, journal->j_uuid, 16);
687 tagp += 16;
688 space_left -= 16;
689 first_tag = 0;
690 }
691
692 /* If there's no more to do, or if the descriptor is full,
693 let the IO rip! */
694
695 if (bufs == journal->j_wbufsize ||
696 commit_transaction->t_buffers == NULL ||
697 space_left < tag_bytes + 16 + csum_size) {
698
699 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
700
701 /* Write an end-of-descriptor marker before
702 submitting the IOs. "tag" still points to
703 the last tag we set up. */
704
705 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
706start_journal_io:
707 if (descriptor)
708 jbd2_descriptor_block_csum_set(journal,
709 descriptor);
710
711 for (i = 0; i < bufs; i++) {
712 struct buffer_head *bh = wbuf[i];
713 /*
714 * Compute checksum.
715 */
716 if (jbd2_has_feature_checksum(journal)) {
717 crc32_sum =
718 jbd2_checksum_data(crc32_sum, bh);
719 }
720
721 lock_buffer(bh);
722 clear_buffer_dirty(bh);
723 set_buffer_uptodate(bh);
724 bh->b_end_io = journal_end_buffer_io_sync;
725 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
726 }
727 cond_resched();
728
729 /* Force a new descriptor to be generated next
730 time round the loop. */
731 descriptor = NULL;
732 bufs = 0;
733 }
734 }
735
736 err = journal_finish_inode_data_buffers(journal, commit_transaction);
737 if (err) {
738 printk(KERN_WARNING
739 "JBD2: Detected IO errors while flushing file data "
740 "on %s\n", journal->j_devname);
741 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
742 jbd2_journal_abort(journal, err);
743 err = 0;
744 }
745
746 /*
747 * Get current oldest transaction in the log before we issue flush
748 * to the filesystem device. After the flush we can be sure that
749 * blocks of all older transactions are checkpointed to persistent
750 * storage and we will be safe to update journal start in the
751 * superblock with the numbers we get here.
752 */
753 update_tail =
754 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
755
756 write_lock(&journal->j_state_lock);
757 if (update_tail) {
758 long freed = first_block - journal->j_tail;
759
760 if (first_block < journal->j_tail)
761 freed += journal->j_last - journal->j_first;
762 /* Update tail only if we free significant amount of space */
763 if (freed < journal->j_maxlen / 4)
764 update_tail = 0;
765 }
766 J_ASSERT(commit_transaction->t_state == T_COMMIT);
767 commit_transaction->t_state = T_COMMIT_DFLUSH;
768 write_unlock(&journal->j_state_lock);
769
770 /*
771 * If the journal is not located on the file system device,
772 * then we must flush the file system device before we issue
773 * the commit record
774 */
775 if (commit_transaction->t_need_data_flush &&
776 (journal->j_fs_dev != journal->j_dev) &&
777 (journal->j_flags & JBD2_BARRIER))
778 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS);
779
780 /* Done it all: now write the commit record asynchronously. */
781 if (jbd2_has_feature_async_commit(journal)) {
782 err = journal_submit_commit_record(journal, commit_transaction,
783 &cbh, crc32_sum);
784 if (err)
785 jbd2_journal_abort(journal, err);
786 }
787
788 blk_finish_plug(&plug);
789
790 /* Lo and behold: we have just managed to send a transaction to
791 the log. Before we can commit it, wait for the IO so far to
792 complete. Control buffers being written are on the
793 transaction's t_log_list queue, and metadata buffers are on
794 the io_bufs list.
795
796 Wait for the buffers in reverse order. That way we are
797 less likely to be woken up until all IOs have completed, and
798 so we incur less scheduling load.
799 */
800
801 jbd_debug(3, "JBD2: commit phase 3\n");
802
803 while (!list_empty(&io_bufs)) {
804 struct buffer_head *bh = list_entry(io_bufs.prev,
805 struct buffer_head,
806 b_assoc_buffers);
807
808 wait_on_buffer(bh);
809 cond_resched();
810
811 if (unlikely(!buffer_uptodate(bh)))
812 err = -EIO;
813 jbd2_unfile_log_bh(bh);
814 stats.run.rs_blocks_logged++;
815
816 /*
817 * The list contains temporary buffer heads created by
818 * jbd2_journal_write_metadata_buffer().
819 */
820 BUFFER_TRACE(bh, "dumping temporary bh");
821 __brelse(bh);
822 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
823 free_buffer_head(bh);
824
825 /* We also have to refile the corresponding shadowed buffer */
826 jh = commit_transaction->t_shadow_list->b_tprev;
827 bh = jh2bh(jh);
828 clear_buffer_jwrite(bh);
829 J_ASSERT_BH(bh, buffer_jbddirty(bh));
830 J_ASSERT_BH(bh, !buffer_shadow(bh));
831
832 /* The metadata is now released for reuse, but we need
833 to remember it against this transaction so that when
834 we finally commit, we can do any checkpointing
835 required. */
836 JBUFFER_TRACE(jh, "file as BJ_Forget");
837 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
838 JBUFFER_TRACE(jh, "brelse shadowed buffer");
839 __brelse(bh);
840 }
841
842 J_ASSERT (commit_transaction->t_shadow_list == NULL);
843
844 jbd_debug(3, "JBD2: commit phase 4\n");
845
846 /* Here we wait for the revoke record and descriptor record buffers */
847 while (!list_empty(&log_bufs)) {
848 struct buffer_head *bh;
849
850 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
851 wait_on_buffer(bh);
852 cond_resched();
853
854 if (unlikely(!buffer_uptodate(bh)))
855 err = -EIO;
856
857 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
858 clear_buffer_jwrite(bh);
859 jbd2_unfile_log_bh(bh);
860 stats.run.rs_blocks_logged++;
861 __brelse(bh); /* One for getblk */
862 /* AKPM: bforget here */
863 }
864
865 if (err)
866 jbd2_journal_abort(journal, err);
867
868 jbd_debug(3, "JBD2: commit phase 5\n");
869 write_lock(&journal->j_state_lock);
870 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
871 commit_transaction->t_state = T_COMMIT_JFLUSH;
872 write_unlock(&journal->j_state_lock);
873
874 if (!jbd2_has_feature_async_commit(journal)) {
875 err = journal_submit_commit_record(journal, commit_transaction,
876 &cbh, crc32_sum);
877 if (err)
878 jbd2_journal_abort(journal, err);
879 }
880 if (cbh)
881 err = journal_wait_on_commit_record(journal, cbh);
882 stats.run.rs_blocks_logged++;
883 if (jbd2_has_feature_async_commit(journal) &&
884 journal->j_flags & JBD2_BARRIER) {
885 blkdev_issue_flush(journal->j_dev, GFP_NOFS);
886 }
887
888 if (err)
889 jbd2_journal_abort(journal, err);
890
891 WARN_ON_ONCE(
892 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
893
894 /*
895 * Now disk caches for filesystem device are flushed so we are safe to
896 * erase checkpointed transactions from the log by updating journal
897 * superblock.
898 */
899 if (update_tail)
900 jbd2_update_log_tail(journal, first_tid, first_block);
901
902 /* End of a transaction! Finally, we can do checkpoint
903 processing: any buffers committed as a result of this
904 transaction can be removed from any checkpoint list it was on
905 before. */
906
907 jbd_debug(3, "JBD2: commit phase 6\n");
908
909 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
910 J_ASSERT(commit_transaction->t_buffers == NULL);
911 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
912 J_ASSERT(commit_transaction->t_shadow_list == NULL);
913
914restart_loop:
915 /*
916 * As there are other places (journal_unmap_buffer()) adding buffers
917 * to this list we have to be careful and hold the j_list_lock.
918 */
919 spin_lock(&journal->j_list_lock);
920 while (commit_transaction->t_forget) {
921 transaction_t *cp_transaction;
922 struct buffer_head *bh;
923 int try_to_free = 0;
924 bool drop_ref;
925
926 jh = commit_transaction->t_forget;
927 spin_unlock(&journal->j_list_lock);
928 bh = jh2bh(jh);
929 /*
930 * Get a reference so that bh cannot be freed before we are
931 * done with it.
932 */
933 get_bh(bh);
934 spin_lock(&jh->b_state_lock);
935 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
936
937 /*
938 * If there is undo-protected committed data against
939 * this buffer, then we can remove it now. If it is a
940 * buffer needing such protection, the old frozen_data
941 * field now points to a committed version of the
942 * buffer, so rotate that field to the new committed
943 * data.
944 *
945 * Otherwise, we can just throw away the frozen data now.
946 *
947 * We also know that the frozen data has already fired
948 * its triggers if they exist, so we can clear that too.
949 */
950 if (jh->b_committed_data) {
951 jbd2_free(jh->b_committed_data, bh->b_size);
952 jh->b_committed_data = NULL;
953 if (jh->b_frozen_data) {
954 jh->b_committed_data = jh->b_frozen_data;
955 jh->b_frozen_data = NULL;
956 jh->b_frozen_triggers = NULL;
957 }
958 } else if (jh->b_frozen_data) {
959 jbd2_free(jh->b_frozen_data, bh->b_size);
960 jh->b_frozen_data = NULL;
961 jh->b_frozen_triggers = NULL;
962 }
963
964 spin_lock(&journal->j_list_lock);
965 cp_transaction = jh->b_cp_transaction;
966 if (cp_transaction) {
967 JBUFFER_TRACE(jh, "remove from old cp transaction");
968 cp_transaction->t_chp_stats.cs_dropped++;
969 __jbd2_journal_remove_checkpoint(jh);
970 }
971
972 /* Only re-checkpoint the buffer_head if it is marked
973 * dirty. If the buffer was added to the BJ_Forget list
974 * by jbd2_journal_forget, it may no longer be dirty and
975 * there's no point in keeping a checkpoint record for
976 * it. */
977
978 /*
979 * A buffer which has been freed while still being journaled
980 * by a previous transaction, refile the buffer to BJ_Forget of
981 * the running transaction. If the just committed transaction
982 * contains "add to orphan" operation, we can completely
983 * invalidate the buffer now. We are rather through in that
984 * since the buffer may be still accessible when blocksize <
985 * pagesize and it is attached to the last partial page.
986 */
987 if (buffer_freed(bh) && !jh->b_next_transaction) {
988 struct address_space *mapping;
989
990 clear_buffer_freed(bh);
991 clear_buffer_jbddirty(bh);
992
993 /*
994 * Block device buffers need to stay mapped all the
995 * time, so it is enough to clear buffer_jbddirty and
996 * buffer_freed bits. For the file mapping buffers (i.e.
997 * journalled data) we need to unmap buffer and clear
998 * more bits. We also need to be careful about the check
999 * because the data page mapping can get cleared under
1000 * our hands. Note that if mapping == NULL, we don't
1001 * need to make buffer unmapped because the page is
1002 * already detached from the mapping and buffers cannot
1003 * get reused.
1004 */
1005 mapping = READ_ONCE(bh->b_page->mapping);
1006 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1007 clear_buffer_mapped(bh);
1008 clear_buffer_new(bh);
1009 clear_buffer_req(bh);
1010 bh->b_bdev = NULL;
1011 }
1012 }
1013
1014 if (buffer_jbddirty(bh)) {
1015 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1016 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1017 if (is_journal_aborted(journal))
1018 clear_buffer_jbddirty(bh);
1019 } else {
1020 J_ASSERT_BH(bh, !buffer_dirty(bh));
1021 /*
1022 * The buffer on BJ_Forget list and not jbddirty means
1023 * it has been freed by this transaction and hence it
1024 * could not have been reallocated until this
1025 * transaction has committed. *BUT* it could be
1026 * reallocated once we have written all the data to
1027 * disk and before we process the buffer on BJ_Forget
1028 * list.
1029 */
1030 if (!jh->b_next_transaction)
1031 try_to_free = 1;
1032 }
1033 JBUFFER_TRACE(jh, "refile or unfile buffer");
1034 drop_ref = __jbd2_journal_refile_buffer(jh);
1035 spin_unlock(&jh->b_state_lock);
1036 if (drop_ref)
1037 jbd2_journal_put_journal_head(jh);
1038 if (try_to_free)
1039 release_buffer_page(bh); /* Drops bh reference */
1040 else
1041 __brelse(bh);
1042 cond_resched_lock(&journal->j_list_lock);
1043 }
1044 spin_unlock(&journal->j_list_lock);
1045 /*
1046 * This is a bit sleazy. We use j_list_lock to protect transition
1047 * of a transaction into T_FINISHED state and calling
1048 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1049 * other checkpointing code processing the transaction...
1050 */
1051 write_lock(&journal->j_state_lock);
1052 spin_lock(&journal->j_list_lock);
1053 /*
1054 * Now recheck if some buffers did not get attached to the transaction
1055 * while the lock was dropped...
1056 */
1057 if (commit_transaction->t_forget) {
1058 spin_unlock(&journal->j_list_lock);
1059 write_unlock(&journal->j_state_lock);
1060 goto restart_loop;
1061 }
1062
1063 /* Add the transaction to the checkpoint list
1064 * __journal_remove_checkpoint() can not destroy transaction
1065 * under us because it is not marked as T_FINISHED yet */
1066 if (journal->j_checkpoint_transactions == NULL) {
1067 journal->j_checkpoint_transactions = commit_transaction;
1068 commit_transaction->t_cpnext = commit_transaction;
1069 commit_transaction->t_cpprev = commit_transaction;
1070 } else {
1071 commit_transaction->t_cpnext =
1072 journal->j_checkpoint_transactions;
1073 commit_transaction->t_cpprev =
1074 commit_transaction->t_cpnext->t_cpprev;
1075 commit_transaction->t_cpnext->t_cpprev =
1076 commit_transaction;
1077 commit_transaction->t_cpprev->t_cpnext =
1078 commit_transaction;
1079 }
1080 spin_unlock(&journal->j_list_lock);
1081
1082 /* Done with this transaction! */
1083
1084 jbd_debug(3, "JBD2: commit phase 7\n");
1085
1086 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1087
1088 commit_transaction->t_start = jiffies;
1089 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1090 commit_transaction->t_start);
1091
1092 /*
1093 * File the transaction statistics
1094 */
1095 stats.ts_tid = commit_transaction->t_tid;
1096 stats.run.rs_handle_count =
1097 atomic_read(&commit_transaction->t_handle_count);
1098 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1099 commit_transaction->t_tid, &stats.run);
1100 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1101
1102 commit_transaction->t_state = T_COMMIT_CALLBACK;
1103 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1104 journal->j_commit_sequence = commit_transaction->t_tid;
1105 journal->j_committing_transaction = NULL;
1106 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1107
1108 /*
1109 * weight the commit time higher than the average time so we don't
1110 * react too strongly to vast changes in the commit time
1111 */
1112 if (likely(journal->j_average_commit_time))
1113 journal->j_average_commit_time = (commit_time +
1114 journal->j_average_commit_time*3) / 4;
1115 else
1116 journal->j_average_commit_time = commit_time;
1117
1118 write_unlock(&journal->j_state_lock);
1119
1120 if (journal->j_commit_callback)
1121 journal->j_commit_callback(journal, commit_transaction);
1122
1123 trace_jbd2_end_commit(journal, commit_transaction);
1124 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1125 journal->j_commit_sequence, journal->j_tail_sequence);
1126
1127 write_lock(&journal->j_state_lock);
1128 spin_lock(&journal->j_list_lock);
1129 commit_transaction->t_state = T_FINISHED;
1130 /* Check if the transaction can be dropped now that we are finished */
1131 if (commit_transaction->t_checkpoint_list == NULL &&
1132 commit_transaction->t_checkpoint_io_list == NULL) {
1133 __jbd2_journal_drop_transaction(journal, commit_transaction);
1134 jbd2_journal_free_transaction(commit_transaction);
1135 }
1136 spin_unlock(&journal->j_list_lock);
1137 write_unlock(&journal->j_state_lock);
1138 wake_up(&journal->j_wait_done_commit);
1139
1140 /*
1141 * Calculate overall stats
1142 */
1143 spin_lock(&journal->j_history_lock);
1144 journal->j_stats.ts_tid++;
1145 journal->j_stats.ts_requested += stats.ts_requested;
1146 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1147 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1148 journal->j_stats.run.rs_running += stats.run.rs_running;
1149 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1150 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1151 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1152 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1153 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1154 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1155 spin_unlock(&journal->j_history_lock);
1156}
1/*
2 * linux/fs/jbd2/commit.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 * Journal commit routines for the generic filesystem journaling code;
13 * part of the ext2fs journaling system.
14 */
15
16#include <linux/time.h>
17#include <linux/fs.h>
18#include <linux/jbd2.h>
19#include <linux/errno.h>
20#include <linux/slab.h>
21#include <linux/mm.h>
22#include <linux/pagemap.h>
23#include <linux/jiffies.h>
24#include <linux/crc32.h>
25#include <linux/writeback.h>
26#include <linux/backing-dev.h>
27#include <linux/bio.h>
28#include <linux/blkdev.h>
29#include <linux/bitops.h>
30#include <trace/events/jbd2.h>
31
32/*
33 * Default IO end handler for temporary BJ_IO buffer_heads.
34 */
35static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
36{
37 BUFFER_TRACE(bh, "");
38 if (uptodate)
39 set_buffer_uptodate(bh);
40 else
41 clear_buffer_uptodate(bh);
42 unlock_buffer(bh);
43}
44
45/*
46 * When an ext4 file is truncated, it is possible that some pages are not
47 * successfully freed, because they are attached to a committing transaction.
48 * After the transaction commits, these pages are left on the LRU, with no
49 * ->mapping, and with attached buffers. These pages are trivially reclaimable
50 * by the VM, but their apparent absence upsets the VM accounting, and it makes
51 * the numbers in /proc/meminfo look odd.
52 *
53 * So here, we have a buffer which has just come off the forget list. Look to
54 * see if we can strip all buffers from the backing page.
55 *
56 * Called under lock_journal(), and possibly under journal_datalist_lock. The
57 * caller provided us with a ref against the buffer, and we drop that here.
58 */
59static void release_buffer_page(struct buffer_head *bh)
60{
61 struct page *page;
62
63 if (buffer_dirty(bh))
64 goto nope;
65 if (atomic_read(&bh->b_count) != 1)
66 goto nope;
67 page = bh->b_page;
68 if (!page)
69 goto nope;
70 if (page->mapping)
71 goto nope;
72
73 /* OK, it's a truncated page */
74 if (!trylock_page(page))
75 goto nope;
76
77 page_cache_get(page);
78 __brelse(bh);
79 try_to_free_buffers(page);
80 unlock_page(page);
81 page_cache_release(page);
82 return;
83
84nope:
85 __brelse(bh);
86}
87
88static void jbd2_commit_block_csum_set(journal_t *j,
89 struct journal_head *descriptor)
90{
91 struct commit_header *h;
92 __u32 csum;
93
94 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
95 return;
96
97 h = (struct commit_header *)(jh2bh(descriptor)->b_data);
98 h->h_chksum_type = 0;
99 h->h_chksum_size = 0;
100 h->h_chksum[0] = 0;
101 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
102 j->j_blocksize);
103 h->h_chksum[0] = cpu_to_be32(csum);
104}
105
106/*
107 * Done it all: now submit the commit record. We should have
108 * cleaned up our previous buffers by now, so if we are in abort
109 * mode we can now just skip the rest of the journal write
110 * entirely.
111 *
112 * Returns 1 if the journal needs to be aborted or 0 on success
113 */
114static int journal_submit_commit_record(journal_t *journal,
115 transaction_t *commit_transaction,
116 struct buffer_head **cbh,
117 __u32 crc32_sum)
118{
119 struct journal_head *descriptor;
120 struct commit_header *tmp;
121 struct buffer_head *bh;
122 int ret;
123 struct timespec now = current_kernel_time();
124
125 *cbh = NULL;
126
127 if (is_journal_aborted(journal))
128 return 0;
129
130 descriptor = jbd2_journal_get_descriptor_buffer(journal);
131 if (!descriptor)
132 return 1;
133
134 bh = jh2bh(descriptor);
135
136 tmp = (struct commit_header *)bh->b_data;
137 tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
138 tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
139 tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (JBD2_HAS_COMPAT_FEATURE(journal,
144 JBD2_FEATURE_COMPAT_CHECKSUM)) {
145 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
146 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
147 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
148 }
149 jbd2_commit_block_csum_set(journal, descriptor);
150
151 JBUFFER_TRACE(descriptor, "submit commit block");
152 lock_buffer(bh);
153 clear_buffer_dirty(bh);
154 set_buffer_uptodate(bh);
155 bh->b_end_io = journal_end_buffer_io_sync;
156
157 if (journal->j_flags & JBD2_BARRIER &&
158 !JBD2_HAS_INCOMPAT_FEATURE(journal,
159 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
160 ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
161 else
162 ret = submit_bh(WRITE_SYNC, bh);
163
164 *cbh = bh;
165 return ret;
166}
167
168/*
169 * This function along with journal_submit_commit_record
170 * allows to write the commit record asynchronously.
171 */
172static int journal_wait_on_commit_record(journal_t *journal,
173 struct buffer_head *bh)
174{
175 int ret = 0;
176
177 clear_buffer_dirty(bh);
178 wait_on_buffer(bh);
179
180 if (unlikely(!buffer_uptodate(bh)))
181 ret = -EIO;
182 put_bh(bh); /* One for getblk() */
183 jbd2_journal_put_journal_head(bh2jh(bh));
184
185 return ret;
186}
187
188/*
189 * write the filemap data using writepage() address_space_operations.
190 * We don't do block allocation here even for delalloc. We don't
191 * use writepages() because with dealyed allocation we may be doing
192 * block allocation in writepages().
193 */
194static int journal_submit_inode_data_buffers(struct address_space *mapping)
195{
196 int ret;
197 struct writeback_control wbc = {
198 .sync_mode = WB_SYNC_ALL,
199 .nr_to_write = mapping->nrpages * 2,
200 .range_start = 0,
201 .range_end = i_size_read(mapping->host),
202 };
203
204 ret = generic_writepages(mapping, &wbc);
205 return ret;
206}
207
208/*
209 * Submit all the data buffers of inode associated with the transaction to
210 * disk.
211 *
212 * We are in a committing transaction. Therefore no new inode can be added to
213 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
214 * operate on from being released while we write out pages.
215 */
216static int journal_submit_data_buffers(journal_t *journal,
217 transaction_t *commit_transaction)
218{
219 struct jbd2_inode *jinode;
220 int err, ret = 0;
221 struct address_space *mapping;
222
223 spin_lock(&journal->j_list_lock);
224 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
225 mapping = jinode->i_vfs_inode->i_mapping;
226 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
227 spin_unlock(&journal->j_list_lock);
228 /*
229 * submit the inode data buffers. We use writepage
230 * instead of writepages. Because writepages can do
231 * block allocation with delalloc. We need to write
232 * only allocated blocks here.
233 */
234 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
235 err = journal_submit_inode_data_buffers(mapping);
236 if (!ret)
237 ret = err;
238 spin_lock(&journal->j_list_lock);
239 J_ASSERT(jinode->i_transaction == commit_transaction);
240 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
241 smp_mb__after_clear_bit();
242 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
243 }
244 spin_unlock(&journal->j_list_lock);
245 return ret;
246}
247
248/*
249 * Wait for data submitted for writeout, refile inodes to proper
250 * transaction if needed.
251 *
252 */
253static int journal_finish_inode_data_buffers(journal_t *journal,
254 transaction_t *commit_transaction)
255{
256 struct jbd2_inode *jinode, *next_i;
257 int err, ret = 0;
258
259 /* For locking, see the comment in journal_submit_data_buffers() */
260 spin_lock(&journal->j_list_lock);
261 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
262 set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
263 spin_unlock(&journal->j_list_lock);
264 err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
265 if (err) {
266 /*
267 * Because AS_EIO is cleared by
268 * filemap_fdatawait_range(), set it again so
269 * that user process can get -EIO from fsync().
270 */
271 set_bit(AS_EIO,
272 &jinode->i_vfs_inode->i_mapping->flags);
273
274 if (!ret)
275 ret = err;
276 }
277 spin_lock(&journal->j_list_lock);
278 clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
279 smp_mb__after_clear_bit();
280 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
281 }
282
283 /* Now refile inode to proper lists */
284 list_for_each_entry_safe(jinode, next_i,
285 &commit_transaction->t_inode_list, i_list) {
286 list_del(&jinode->i_list);
287 if (jinode->i_next_transaction) {
288 jinode->i_transaction = jinode->i_next_transaction;
289 jinode->i_next_transaction = NULL;
290 list_add(&jinode->i_list,
291 &jinode->i_transaction->t_inode_list);
292 } else {
293 jinode->i_transaction = NULL;
294 }
295 }
296 spin_unlock(&journal->j_list_lock);
297
298 return ret;
299}
300
301static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
302{
303 struct page *page = bh->b_page;
304 char *addr;
305 __u32 checksum;
306
307 addr = kmap_atomic(page);
308 checksum = crc32_be(crc32_sum,
309 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
310 kunmap_atomic(addr);
311
312 return checksum;
313}
314
315static void write_tag_block(int tag_bytes, journal_block_tag_t *tag,
316 unsigned long long block)
317{
318 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
319 if (tag_bytes > JBD2_TAG_SIZE32)
320 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
321}
322
323static void jbd2_descr_block_csum_set(journal_t *j,
324 struct journal_head *descriptor)
325{
326 struct jbd2_journal_block_tail *tail;
327 __u32 csum;
328
329 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
330 return;
331
332 tail = (struct jbd2_journal_block_tail *)
333 (jh2bh(descriptor)->b_data + j->j_blocksize -
334 sizeof(struct jbd2_journal_block_tail));
335 tail->t_checksum = 0;
336 csum = jbd2_chksum(j, j->j_csum_seed, jh2bh(descriptor)->b_data,
337 j->j_blocksize);
338 tail->t_checksum = cpu_to_be32(csum);
339}
340
341static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
342 struct buffer_head *bh, __u32 sequence)
343{
344 struct page *page = bh->b_page;
345 __u8 *addr;
346 __u32 csum;
347
348 if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
349 return;
350
351 sequence = cpu_to_be32(sequence);
352 addr = kmap_atomic(page, KM_USER0);
353 csum = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&sequence,
354 sizeof(sequence));
355 csum = jbd2_chksum(j, csum, addr + offset_in_page(bh->b_data),
356 bh->b_size);
357 kunmap_atomic(addr, KM_USER0);
358
359 tag->t_checksum = cpu_to_be32(csum);
360}
361/*
362 * jbd2_journal_commit_transaction
363 *
364 * The primary function for committing a transaction to the log. This
365 * function is called by the journal thread to begin a complete commit.
366 */
367void jbd2_journal_commit_transaction(journal_t *journal)
368{
369 struct transaction_stats_s stats;
370 transaction_t *commit_transaction;
371 struct journal_head *jh, *new_jh, *descriptor;
372 struct buffer_head **wbuf = journal->j_wbuf;
373 int bufs;
374 int flags;
375 int err;
376 unsigned long long blocknr;
377 ktime_t start_time;
378 u64 commit_time;
379 char *tagp = NULL;
380 journal_header_t *header;
381 journal_block_tag_t *tag = NULL;
382 int space_left = 0;
383 int first_tag = 0;
384 int tag_flag;
385 int i, to_free = 0;
386 int tag_bytes = journal_tag_bytes(journal);
387 struct buffer_head *cbh = NULL; /* For transactional checksums */
388 __u32 crc32_sum = ~0;
389 struct blk_plug plug;
390 /* Tail of the journal */
391 unsigned long first_block;
392 tid_t first_tid;
393 int update_tail;
394 int csum_size = 0;
395
396 if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
397 csum_size = sizeof(struct jbd2_journal_block_tail);
398
399 /*
400 * First job: lock down the current transaction and wait for
401 * all outstanding updates to complete.
402 */
403
404 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
405 if (journal->j_flags & JBD2_FLUSHED) {
406 jbd_debug(3, "super block updated\n");
407 mutex_lock(&journal->j_checkpoint_mutex);
408 /*
409 * We hold j_checkpoint_mutex so tail cannot change under us.
410 * We don't need any special data guarantees for writing sb
411 * since journal is empty and it is ok for write to be
412 * flushed only with transaction commit.
413 */
414 jbd2_journal_update_sb_log_tail(journal,
415 journal->j_tail_sequence,
416 journal->j_tail,
417 WRITE_SYNC);
418 mutex_unlock(&journal->j_checkpoint_mutex);
419 } else {
420 jbd_debug(3, "superblock not updated\n");
421 }
422
423 J_ASSERT(journal->j_running_transaction != NULL);
424 J_ASSERT(journal->j_committing_transaction == NULL);
425
426 commit_transaction = journal->j_running_transaction;
427 J_ASSERT(commit_transaction->t_state == T_RUNNING);
428
429 trace_jbd2_start_commit(journal, commit_transaction);
430 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
431 commit_transaction->t_tid);
432
433 write_lock(&journal->j_state_lock);
434 commit_transaction->t_state = T_LOCKED;
435
436 trace_jbd2_commit_locking(journal, commit_transaction);
437 stats.run.rs_wait = commit_transaction->t_max_wait;
438 stats.run.rs_locked = jiffies;
439 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
440 stats.run.rs_locked);
441
442 spin_lock(&commit_transaction->t_handle_lock);
443 while (atomic_read(&commit_transaction->t_updates)) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_wait_updates, &wait,
447 TASK_UNINTERRUPTIBLE);
448 if (atomic_read(&commit_transaction->t_updates)) {
449 spin_unlock(&commit_transaction->t_handle_lock);
450 write_unlock(&journal->j_state_lock);
451 schedule();
452 write_lock(&journal->j_state_lock);
453 spin_lock(&commit_transaction->t_handle_lock);
454 }
455 finish_wait(&journal->j_wait_updates, &wait);
456 }
457 spin_unlock(&commit_transaction->t_handle_lock);
458
459 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
460 journal->j_max_transaction_buffers);
461
462 /*
463 * First thing we are allowed to do is to discard any remaining
464 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
465 * that there are no such buffers: if a large filesystem
466 * operation like a truncate needs to split itself over multiple
467 * transactions, then it may try to do a jbd2_journal_restart() while
468 * there are still BJ_Reserved buffers outstanding. These must
469 * be released cleanly from the current transaction.
470 *
471 * In this case, the filesystem must still reserve write access
472 * again before modifying the buffer in the new transaction, but
473 * we do not require it to remember exactly which old buffers it
474 * has reserved. This is consistent with the existing behaviour
475 * that multiple jbd2_journal_get_write_access() calls to the same
476 * buffer are perfectly permissible.
477 */
478 while (commit_transaction->t_reserved_list) {
479 jh = commit_transaction->t_reserved_list;
480 JBUFFER_TRACE(jh, "reserved, unused: refile");
481 /*
482 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
483 * leave undo-committed data.
484 */
485 if (jh->b_committed_data) {
486 struct buffer_head *bh = jh2bh(jh);
487
488 jbd_lock_bh_state(bh);
489 jbd2_free(jh->b_committed_data, bh->b_size);
490 jh->b_committed_data = NULL;
491 jbd_unlock_bh_state(bh);
492 }
493 jbd2_journal_refile_buffer(journal, jh);
494 }
495
496 /*
497 * Now try to drop any written-back buffers from the journal's
498 * checkpoint lists. We do this *before* commit because it potentially
499 * frees some memory
500 */
501 spin_lock(&journal->j_list_lock);
502 __jbd2_journal_clean_checkpoint_list(journal);
503 spin_unlock(&journal->j_list_lock);
504
505 jbd_debug(3, "JBD2: commit phase 1\n");
506
507 /*
508 * Clear revoked flag to reflect there is no revoked buffers
509 * in the next transaction which is going to be started.
510 */
511 jbd2_clear_buffer_revoked_flags(journal);
512
513 /*
514 * Switch to a new revoke table.
515 */
516 jbd2_journal_switch_revoke_table(journal);
517
518 trace_jbd2_commit_flushing(journal, commit_transaction);
519 stats.run.rs_flushing = jiffies;
520 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
521 stats.run.rs_flushing);
522
523 commit_transaction->t_state = T_FLUSH;
524 journal->j_committing_transaction = commit_transaction;
525 journal->j_running_transaction = NULL;
526 start_time = ktime_get();
527 commit_transaction->t_log_start = journal->j_head;
528 wake_up(&journal->j_wait_transaction_locked);
529 write_unlock(&journal->j_state_lock);
530
531 jbd_debug(3, "JBD2: commit phase 2\n");
532
533 /*
534 * Now start flushing things to disk, in the order they appear
535 * on the transaction lists. Data blocks go first.
536 */
537 err = journal_submit_data_buffers(journal, commit_transaction);
538 if (err)
539 jbd2_journal_abort(journal, err);
540
541 blk_start_plug(&plug);
542 jbd2_journal_write_revoke_records(journal, commit_transaction,
543 WRITE_SYNC);
544 blk_finish_plug(&plug);
545
546 jbd_debug(3, "JBD2: commit phase 2\n");
547
548 /*
549 * Way to go: we have now written out all of the data for a
550 * transaction! Now comes the tricky part: we need to write out
551 * metadata. Loop over the transaction's entire buffer list:
552 */
553 write_lock(&journal->j_state_lock);
554 commit_transaction->t_state = T_COMMIT;
555 write_unlock(&journal->j_state_lock);
556
557 trace_jbd2_commit_logging(journal, commit_transaction);
558 stats.run.rs_logging = jiffies;
559 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
560 stats.run.rs_logging);
561 stats.run.rs_blocks =
562 atomic_read(&commit_transaction->t_outstanding_credits);
563 stats.run.rs_blocks_logged = 0;
564
565 J_ASSERT(commit_transaction->t_nr_buffers <=
566 atomic_read(&commit_transaction->t_outstanding_credits));
567
568 err = 0;
569 descriptor = NULL;
570 bufs = 0;
571 blk_start_plug(&plug);
572 while (commit_transaction->t_buffers) {
573
574 /* Find the next buffer to be journaled... */
575
576 jh = commit_transaction->t_buffers;
577
578 /* If we're in abort mode, we just un-journal the buffer and
579 release it. */
580
581 if (is_journal_aborted(journal)) {
582 clear_buffer_jbddirty(jh2bh(jh));
583 JBUFFER_TRACE(jh, "journal is aborting: refile");
584 jbd2_buffer_abort_trigger(jh,
585 jh->b_frozen_data ?
586 jh->b_frozen_triggers :
587 jh->b_triggers);
588 jbd2_journal_refile_buffer(journal, jh);
589 /* If that was the last one, we need to clean up
590 * any descriptor buffers which may have been
591 * already allocated, even if we are now
592 * aborting. */
593 if (!commit_transaction->t_buffers)
594 goto start_journal_io;
595 continue;
596 }
597
598 /* Make sure we have a descriptor block in which to
599 record the metadata buffer. */
600
601 if (!descriptor) {
602 struct buffer_head *bh;
603
604 J_ASSERT (bufs == 0);
605
606 jbd_debug(4, "JBD2: get descriptor\n");
607
608 descriptor = jbd2_journal_get_descriptor_buffer(journal);
609 if (!descriptor) {
610 jbd2_journal_abort(journal, -EIO);
611 continue;
612 }
613
614 bh = jh2bh(descriptor);
615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
616 (unsigned long long)bh->b_blocknr, bh->b_data);
617 header = (journal_header_t *)&bh->b_data[0];
618 header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
619 header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
620 header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
621
622 tagp = &bh->b_data[sizeof(journal_header_t)];
623 space_left = bh->b_size - sizeof(journal_header_t);
624 first_tag = 1;
625 set_buffer_jwrite(bh);
626 set_buffer_dirty(bh);
627 wbuf[bufs++] = bh;
628
629 /* Record it so that we can wait for IO
630 completion later */
631 BUFFER_TRACE(bh, "ph3: file as descriptor");
632 jbd2_journal_file_buffer(descriptor, commit_transaction,
633 BJ_LogCtl);
634 }
635
636 /* Where is the buffer to be written? */
637
638 err = jbd2_journal_next_log_block(journal, &blocknr);
639 /* If the block mapping failed, just abandon the buffer
640 and repeat this loop: we'll fall into the
641 refile-on-abort condition above. */
642 if (err) {
643 jbd2_journal_abort(journal, err);
644 continue;
645 }
646
647 /*
648 * start_this_handle() uses t_outstanding_credits to determine
649 * the free space in the log, but this counter is changed
650 * by jbd2_journal_next_log_block() also.
651 */
652 atomic_dec(&commit_transaction->t_outstanding_credits);
653
654 /* Bump b_count to prevent truncate from stumbling over
655 the shadowed buffer! @@@ This can go if we ever get
656 rid of the BJ_IO/BJ_Shadow pairing of buffers. */
657 atomic_inc(&jh2bh(jh)->b_count);
658
659 /* Make a temporary IO buffer with which to write it out
660 (this will requeue both the metadata buffer and the
661 temporary IO buffer). new_bh goes on BJ_IO*/
662
663 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
664 /*
665 * akpm: jbd2_journal_write_metadata_buffer() sets
666 * new_bh->b_transaction to commit_transaction.
667 * We need to clean this up before we release new_bh
668 * (which is of type BJ_IO)
669 */
670 JBUFFER_TRACE(jh, "ph3: write metadata");
671 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
672 jh, &new_jh, blocknr);
673 if (flags < 0) {
674 jbd2_journal_abort(journal, flags);
675 continue;
676 }
677 set_bit(BH_JWrite, &jh2bh(new_jh)->b_state);
678 wbuf[bufs++] = jh2bh(new_jh);
679
680 /* Record the new block's tag in the current descriptor
681 buffer */
682
683 tag_flag = 0;
684 if (flags & 1)
685 tag_flag |= JBD2_FLAG_ESCAPE;
686 if (!first_tag)
687 tag_flag |= JBD2_FLAG_SAME_UUID;
688
689 tag = (journal_block_tag_t *) tagp;
690 write_tag_block(tag_bytes, tag, jh2bh(jh)->b_blocknr);
691 tag->t_flags = cpu_to_be16(tag_flag);
692 jbd2_block_tag_csum_set(journal, tag, jh2bh(new_jh),
693 commit_transaction->t_tid);
694 tagp += tag_bytes;
695 space_left -= tag_bytes;
696
697 if (first_tag) {
698 memcpy (tagp, journal->j_uuid, 16);
699 tagp += 16;
700 space_left -= 16;
701 first_tag = 0;
702 }
703
704 /* If there's no more to do, or if the descriptor is full,
705 let the IO rip! */
706
707 if (bufs == journal->j_wbufsize ||
708 commit_transaction->t_buffers == NULL ||
709 space_left < tag_bytes + 16 + csum_size) {
710
711 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
712
713 /* Write an end-of-descriptor marker before
714 submitting the IOs. "tag" still points to
715 the last tag we set up. */
716
717 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
718
719 jbd2_descr_block_csum_set(journal, descriptor);
720start_journal_io:
721 for (i = 0; i < bufs; i++) {
722 struct buffer_head *bh = wbuf[i];
723 /*
724 * Compute checksum.
725 */
726 if (JBD2_HAS_COMPAT_FEATURE(journal,
727 JBD2_FEATURE_COMPAT_CHECKSUM)) {
728 crc32_sum =
729 jbd2_checksum_data(crc32_sum, bh);
730 }
731
732 lock_buffer(bh);
733 clear_buffer_dirty(bh);
734 set_buffer_uptodate(bh);
735 bh->b_end_io = journal_end_buffer_io_sync;
736 submit_bh(WRITE_SYNC, bh);
737 }
738 cond_resched();
739 stats.run.rs_blocks_logged += bufs;
740
741 /* Force a new descriptor to be generated next
742 time round the loop. */
743 descriptor = NULL;
744 bufs = 0;
745 }
746 }
747
748 err = journal_finish_inode_data_buffers(journal, commit_transaction);
749 if (err) {
750 printk(KERN_WARNING
751 "JBD2: Detected IO errors while flushing file data "
752 "on %s\n", journal->j_devname);
753 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
754 jbd2_journal_abort(journal, err);
755 err = 0;
756 }
757
758 /*
759 * Get current oldest transaction in the log before we issue flush
760 * to the filesystem device. After the flush we can be sure that
761 * blocks of all older transactions are checkpointed to persistent
762 * storage and we will be safe to update journal start in the
763 * superblock with the numbers we get here.
764 */
765 update_tail =
766 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
767
768 write_lock(&journal->j_state_lock);
769 if (update_tail) {
770 long freed = first_block - journal->j_tail;
771
772 if (first_block < journal->j_tail)
773 freed += journal->j_last - journal->j_first;
774 /* Update tail only if we free significant amount of space */
775 if (freed < journal->j_maxlen / 4)
776 update_tail = 0;
777 }
778 J_ASSERT(commit_transaction->t_state == T_COMMIT);
779 commit_transaction->t_state = T_COMMIT_DFLUSH;
780 write_unlock(&journal->j_state_lock);
781
782 /*
783 * If the journal is not located on the file system device,
784 * then we must flush the file system device before we issue
785 * the commit record
786 */
787 if (commit_transaction->t_need_data_flush &&
788 (journal->j_fs_dev != journal->j_dev) &&
789 (journal->j_flags & JBD2_BARRIER))
790 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
791
792 /* Done it all: now write the commit record asynchronously. */
793 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
794 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
795 err = journal_submit_commit_record(journal, commit_transaction,
796 &cbh, crc32_sum);
797 if (err)
798 __jbd2_journal_abort_hard(journal);
799 }
800
801 blk_finish_plug(&plug);
802
803 /* Lo and behold: we have just managed to send a transaction to
804 the log. Before we can commit it, wait for the IO so far to
805 complete. Control buffers being written are on the
806 transaction's t_log_list queue, and metadata buffers are on
807 the t_iobuf_list queue.
808
809 Wait for the buffers in reverse order. That way we are
810 less likely to be woken up until all IOs have completed, and
811 so we incur less scheduling load.
812 */
813
814 jbd_debug(3, "JBD2: commit phase 3\n");
815
816 /*
817 * akpm: these are BJ_IO, and j_list_lock is not needed.
818 * See __journal_try_to_free_buffer.
819 */
820wait_for_iobuf:
821 while (commit_transaction->t_iobuf_list != NULL) {
822 struct buffer_head *bh;
823
824 jh = commit_transaction->t_iobuf_list->b_tprev;
825 bh = jh2bh(jh);
826 if (buffer_locked(bh)) {
827 wait_on_buffer(bh);
828 goto wait_for_iobuf;
829 }
830 if (cond_resched())
831 goto wait_for_iobuf;
832
833 if (unlikely(!buffer_uptodate(bh)))
834 err = -EIO;
835
836 clear_buffer_jwrite(bh);
837
838 JBUFFER_TRACE(jh, "ph4: unfile after journal write");
839 jbd2_journal_unfile_buffer(journal, jh);
840
841 /*
842 * ->t_iobuf_list should contain only dummy buffer_heads
843 * which were created by jbd2_journal_write_metadata_buffer().
844 */
845 BUFFER_TRACE(bh, "dumping temporary bh");
846 jbd2_journal_put_journal_head(jh);
847 __brelse(bh);
848 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
849 free_buffer_head(bh);
850
851 /* We also have to unlock and free the corresponding
852 shadowed buffer */
853 jh = commit_transaction->t_shadow_list->b_tprev;
854 bh = jh2bh(jh);
855 clear_bit(BH_JWrite, &bh->b_state);
856 J_ASSERT_BH(bh, buffer_jbddirty(bh));
857
858 /* The metadata is now released for reuse, but we need
859 to remember it against this transaction so that when
860 we finally commit, we can do any checkpointing
861 required. */
862 JBUFFER_TRACE(jh, "file as BJ_Forget");
863 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
864 /*
865 * Wake up any transactions which were waiting for this IO to
866 * complete. The barrier must be here so that changes by
867 * jbd2_journal_file_buffer() take effect before wake_up_bit()
868 * does the waitqueue check.
869 */
870 smp_mb();
871 wake_up_bit(&bh->b_state, BH_Unshadow);
872 JBUFFER_TRACE(jh, "brelse shadowed buffer");
873 __brelse(bh);
874 }
875
876 J_ASSERT (commit_transaction->t_shadow_list == NULL);
877
878 jbd_debug(3, "JBD2: commit phase 4\n");
879
880 /* Here we wait for the revoke record and descriptor record buffers */
881 wait_for_ctlbuf:
882 while (commit_transaction->t_log_list != NULL) {
883 struct buffer_head *bh;
884
885 jh = commit_transaction->t_log_list->b_tprev;
886 bh = jh2bh(jh);
887 if (buffer_locked(bh)) {
888 wait_on_buffer(bh);
889 goto wait_for_ctlbuf;
890 }
891 if (cond_resched())
892 goto wait_for_ctlbuf;
893
894 if (unlikely(!buffer_uptodate(bh)))
895 err = -EIO;
896
897 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
898 clear_buffer_jwrite(bh);
899 jbd2_journal_unfile_buffer(journal, jh);
900 jbd2_journal_put_journal_head(jh);
901 __brelse(bh); /* One for getblk */
902 /* AKPM: bforget here */
903 }
904
905 if (err)
906 jbd2_journal_abort(journal, err);
907
908 jbd_debug(3, "JBD2: commit phase 5\n");
909 write_lock(&journal->j_state_lock);
910 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
911 commit_transaction->t_state = T_COMMIT_JFLUSH;
912 write_unlock(&journal->j_state_lock);
913
914 if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
915 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
916 err = journal_submit_commit_record(journal, commit_transaction,
917 &cbh, crc32_sum);
918 if (err)
919 __jbd2_journal_abort_hard(journal);
920 }
921 if (cbh)
922 err = journal_wait_on_commit_record(journal, cbh);
923 if (JBD2_HAS_INCOMPAT_FEATURE(journal,
924 JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
925 journal->j_flags & JBD2_BARRIER) {
926 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
927 }
928
929 if (err)
930 jbd2_journal_abort(journal, err);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_iobuf_list == NULL);
951 J_ASSERT(commit_transaction->t_shadow_list == NULL);
952 J_ASSERT(commit_transaction->t_log_list == NULL);
953
954restart_loop:
955 /*
956 * As there are other places (journal_unmap_buffer()) adding buffers
957 * to this list we have to be careful and hold the j_list_lock.
958 */
959 spin_lock(&journal->j_list_lock);
960 while (commit_transaction->t_forget) {
961 transaction_t *cp_transaction;
962 struct buffer_head *bh;
963 int try_to_free = 0;
964
965 jh = commit_transaction->t_forget;
966 spin_unlock(&journal->j_list_lock);
967 bh = jh2bh(jh);
968 /*
969 * Get a reference so that bh cannot be freed before we are
970 * done with it.
971 */
972 get_bh(bh);
973 jbd_lock_bh_state(bh);
974 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
975
976 /*
977 * If there is undo-protected committed data against
978 * this buffer, then we can remove it now. If it is a
979 * buffer needing such protection, the old frozen_data
980 * field now points to a committed version of the
981 * buffer, so rotate that field to the new committed
982 * data.
983 *
984 * Otherwise, we can just throw away the frozen data now.
985 *
986 * We also know that the frozen data has already fired
987 * its triggers if they exist, so we can clear that too.
988 */
989 if (jh->b_committed_data) {
990 jbd2_free(jh->b_committed_data, bh->b_size);
991 jh->b_committed_data = NULL;
992 if (jh->b_frozen_data) {
993 jh->b_committed_data = jh->b_frozen_data;
994 jh->b_frozen_data = NULL;
995 jh->b_frozen_triggers = NULL;
996 }
997 } else if (jh->b_frozen_data) {
998 jbd2_free(jh->b_frozen_data, bh->b_size);
999 jh->b_frozen_data = NULL;
1000 jh->b_frozen_triggers = NULL;
1001 }
1002
1003 spin_lock(&journal->j_list_lock);
1004 cp_transaction = jh->b_cp_transaction;
1005 if (cp_transaction) {
1006 JBUFFER_TRACE(jh, "remove from old cp transaction");
1007 cp_transaction->t_chp_stats.cs_dropped++;
1008 __jbd2_journal_remove_checkpoint(jh);
1009 }
1010
1011 /* Only re-checkpoint the buffer_head if it is marked
1012 * dirty. If the buffer was added to the BJ_Forget list
1013 * by jbd2_journal_forget, it may no longer be dirty and
1014 * there's no point in keeping a checkpoint record for
1015 * it. */
1016
1017 /* A buffer which has been freed while still being
1018 * journaled by a previous transaction may end up still
1019 * being dirty here, but we want to avoid writing back
1020 * that buffer in the future after the "add to orphan"
1021 * operation been committed, That's not only a performance
1022 * gain, it also stops aliasing problems if the buffer is
1023 * left behind for writeback and gets reallocated for another
1024 * use in a different page. */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 clear_buffer_freed(bh);
1027 clear_buffer_jbddirty(bh);
1028 }
1029
1030 if (buffer_jbddirty(bh)) {
1031 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1032 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1033 if (is_journal_aborted(journal))
1034 clear_buffer_jbddirty(bh);
1035 } else {
1036 J_ASSERT_BH(bh, !buffer_dirty(bh));
1037 /*
1038 * The buffer on BJ_Forget list and not jbddirty means
1039 * it has been freed by this transaction and hence it
1040 * could not have been reallocated until this
1041 * transaction has committed. *BUT* it could be
1042 * reallocated once we have written all the data to
1043 * disk and before we process the buffer on BJ_Forget
1044 * list.
1045 */
1046 if (!jh->b_next_transaction)
1047 try_to_free = 1;
1048 }
1049 JBUFFER_TRACE(jh, "refile or unfile buffer");
1050 __jbd2_journal_refile_buffer(jh);
1051 jbd_unlock_bh_state(bh);
1052 if (try_to_free)
1053 release_buffer_page(bh); /* Drops bh reference */
1054 else
1055 __brelse(bh);
1056 cond_resched_lock(&journal->j_list_lock);
1057 }
1058 spin_unlock(&journal->j_list_lock);
1059 /*
1060 * This is a bit sleazy. We use j_list_lock to protect transition
1061 * of a transaction into T_FINISHED state and calling
1062 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1063 * other checkpointing code processing the transaction...
1064 */
1065 write_lock(&journal->j_state_lock);
1066 spin_lock(&journal->j_list_lock);
1067 /*
1068 * Now recheck if some buffers did not get attached to the transaction
1069 * while the lock was dropped...
1070 */
1071 if (commit_transaction->t_forget) {
1072 spin_unlock(&journal->j_list_lock);
1073 write_unlock(&journal->j_state_lock);
1074 goto restart_loop;
1075 }
1076
1077 /* Done with this transaction! */
1078
1079 jbd_debug(3, "JBD2: commit phase 7\n");
1080
1081 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1082
1083 commit_transaction->t_start = jiffies;
1084 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1085 commit_transaction->t_start);
1086
1087 /*
1088 * File the transaction statistics
1089 */
1090 stats.ts_tid = commit_transaction->t_tid;
1091 stats.run.rs_handle_count =
1092 atomic_read(&commit_transaction->t_handle_count);
1093 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1094 commit_transaction->t_tid, &stats.run);
1095
1096 /*
1097 * Calculate overall stats
1098 */
1099 spin_lock(&journal->j_history_lock);
1100 journal->j_stats.ts_tid++;
1101 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1102 journal->j_stats.run.rs_running += stats.run.rs_running;
1103 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1104 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1105 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1106 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1107 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1108 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1109 spin_unlock(&journal->j_history_lock);
1110
1111 commit_transaction->t_state = T_FINISHED;
1112 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1113 journal->j_commit_sequence = commit_transaction->t_tid;
1114 journal->j_committing_transaction = NULL;
1115 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1116
1117 /*
1118 * weight the commit time higher than the average time so we don't
1119 * react too strongly to vast changes in the commit time
1120 */
1121 if (likely(journal->j_average_commit_time))
1122 journal->j_average_commit_time = (commit_time +
1123 journal->j_average_commit_time*3) / 4;
1124 else
1125 journal->j_average_commit_time = commit_time;
1126 write_unlock(&journal->j_state_lock);
1127
1128 if (commit_transaction->t_checkpoint_list == NULL &&
1129 commit_transaction->t_checkpoint_io_list == NULL) {
1130 __jbd2_journal_drop_transaction(journal, commit_transaction);
1131 to_free = 1;
1132 } else {
1133 if (journal->j_checkpoint_transactions == NULL) {
1134 journal->j_checkpoint_transactions = commit_transaction;
1135 commit_transaction->t_cpnext = commit_transaction;
1136 commit_transaction->t_cpprev = commit_transaction;
1137 } else {
1138 commit_transaction->t_cpnext =
1139 journal->j_checkpoint_transactions;
1140 commit_transaction->t_cpprev =
1141 commit_transaction->t_cpnext->t_cpprev;
1142 commit_transaction->t_cpnext->t_cpprev =
1143 commit_transaction;
1144 commit_transaction->t_cpprev->t_cpnext =
1145 commit_transaction;
1146 }
1147 }
1148 spin_unlock(&journal->j_list_lock);
1149
1150 if (journal->j_commit_callback)
1151 journal->j_commit_callback(journal, commit_transaction);
1152
1153 trace_jbd2_end_commit(journal, commit_transaction);
1154 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1155 journal->j_commit_sequence, journal->j_tail_sequence);
1156 if (to_free)
1157 jbd2_journal_free_transaction(commit_transaction);
1158
1159 wake_up(&journal->j_wait_done_commit);
1160}