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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// 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 jbd_lock_bh_state(bh);
486 jbd2_free(jh->b_committed_data, bh->b_size);
487 jh->b_committed_data = NULL;
488 jbd_unlock_bh_state(bh);
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 =
564 atomic_read(&commit_transaction->t_outstanding_credits);
565 stats.run.rs_blocks_logged = 0;
566
567 J_ASSERT(commit_transaction->t_nr_buffers <=
568 atomic_read(&commit_transaction->t_outstanding_credits));
569
570 err = 0;
571 bufs = 0;
572 descriptor = NULL;
573 while (commit_transaction->t_buffers) {
574
575 /* Find the next buffer to be journaled... */
576
577 jh = commit_transaction->t_buffers;
578
579 /* If we're in abort mode, we just un-journal the buffer and
580 release it. */
581
582 if (is_journal_aborted(journal)) {
583 clear_buffer_jbddirty(jh2bh(jh));
584 JBUFFER_TRACE(jh, "journal is aborting: refile");
585 jbd2_buffer_abort_trigger(jh,
586 jh->b_frozen_data ?
587 jh->b_frozen_triggers :
588 jh->b_triggers);
589 jbd2_journal_refile_buffer(journal, jh);
590 /* If that was the last one, we need to clean up
591 * any descriptor buffers which may have been
592 * already allocated, even if we are now
593 * aborting. */
594 if (!commit_transaction->t_buffers)
595 goto start_journal_io;
596 continue;
597 }
598
599 /* Make sure we have a descriptor block in which to
600 record the metadata buffer. */
601
602 if (!descriptor) {
603 J_ASSERT (bufs == 0);
604
605 jbd_debug(4, "JBD2: get descriptor\n");
606
607 descriptor = jbd2_journal_get_descriptor_buffer(
608 commit_transaction,
609 JBD2_DESCRIPTOR_BLOCK);
610 if (!descriptor) {
611 jbd2_journal_abort(journal, -EIO);
612 continue;
613 }
614
615 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
616 (unsigned long long)descriptor->b_blocknr,
617 descriptor->b_data);
618 tagp = &descriptor->b_data[sizeof(journal_header_t)];
619 space_left = descriptor->b_size -
620 sizeof(journal_header_t);
621 first_tag = 1;
622 set_buffer_jwrite(descriptor);
623 set_buffer_dirty(descriptor);
624 wbuf[bufs++] = descriptor;
625
626 /* Record it so that we can wait for IO
627 completion later */
628 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
629 jbd2_file_log_bh(&log_bufs, descriptor);
630 }
631
632 /* Where is the buffer to be written? */
633
634 err = jbd2_journal_next_log_block(journal, &blocknr);
635 /* If the block mapping failed, just abandon the buffer
636 and repeat this loop: we'll fall into the
637 refile-on-abort condition above. */
638 if (err) {
639 jbd2_journal_abort(journal, err);
640 continue;
641 }
642
643 /*
644 * start_this_handle() uses t_outstanding_credits to determine
645 * the free space in the log, but this counter is changed
646 * by jbd2_journal_next_log_block() also.
647 */
648 atomic_dec(&commit_transaction->t_outstanding_credits);
649
650 /* Bump b_count to prevent truncate from stumbling over
651 the shadowed buffer! @@@ This can go if we ever get
652 rid of the shadow pairing of buffers. */
653 atomic_inc(&jh2bh(jh)->b_count);
654
655 /*
656 * Make a temporary IO buffer with which to write it out
657 * (this will requeue the metadata buffer to BJ_Shadow).
658 */
659 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
660 JBUFFER_TRACE(jh, "ph3: write metadata");
661 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
662 jh, &wbuf[bufs], blocknr);
663 if (flags < 0) {
664 jbd2_journal_abort(journal, flags);
665 continue;
666 }
667 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
668
669 /* Record the new block's tag in the current descriptor
670 buffer */
671
672 tag_flag = 0;
673 if (flags & 1)
674 tag_flag |= JBD2_FLAG_ESCAPE;
675 if (!first_tag)
676 tag_flag |= JBD2_FLAG_SAME_UUID;
677
678 tag = (journal_block_tag_t *) tagp;
679 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
680 tag->t_flags = cpu_to_be16(tag_flag);
681 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
682 commit_transaction->t_tid);
683 tagp += tag_bytes;
684 space_left -= tag_bytes;
685 bufs++;
686
687 if (first_tag) {
688 memcpy (tagp, journal->j_uuid, 16);
689 tagp += 16;
690 space_left -= 16;
691 first_tag = 0;
692 }
693
694 /* If there's no more to do, or if the descriptor is full,
695 let the IO rip! */
696
697 if (bufs == journal->j_wbufsize ||
698 commit_transaction->t_buffers == NULL ||
699 space_left < tag_bytes + 16 + csum_size) {
700
701 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
702
703 /* Write an end-of-descriptor marker before
704 submitting the IOs. "tag" still points to
705 the last tag we set up. */
706
707 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
708start_journal_io:
709 if (descriptor)
710 jbd2_descriptor_block_csum_set(journal,
711 descriptor);
712
713 for (i = 0; i < bufs; i++) {
714 struct buffer_head *bh = wbuf[i];
715 /*
716 * Compute checksum.
717 */
718 if (jbd2_has_feature_checksum(journal)) {
719 crc32_sum =
720 jbd2_checksum_data(crc32_sum, bh);
721 }
722
723 lock_buffer(bh);
724 clear_buffer_dirty(bh);
725 set_buffer_uptodate(bh);
726 bh->b_end_io = journal_end_buffer_io_sync;
727 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
728 }
729 cond_resched();
730 stats.run.rs_blocks_logged += bufs;
731
732 /* Force a new descriptor to be generated next
733 time round the loop. */
734 descriptor = NULL;
735 bufs = 0;
736 }
737 }
738
739 err = journal_finish_inode_data_buffers(journal, commit_transaction);
740 if (err) {
741 printk(KERN_WARNING
742 "JBD2: Detected IO errors while flushing file data "
743 "on %s\n", journal->j_devname);
744 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
745 jbd2_journal_abort(journal, err);
746 err = 0;
747 }
748
749 /*
750 * Get current oldest transaction in the log before we issue flush
751 * to the filesystem device. After the flush we can be sure that
752 * blocks of all older transactions are checkpointed to persistent
753 * storage and we will be safe to update journal start in the
754 * superblock with the numbers we get here.
755 */
756 update_tail =
757 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
758
759 write_lock(&journal->j_state_lock);
760 if (update_tail) {
761 long freed = first_block - journal->j_tail;
762
763 if (first_block < journal->j_tail)
764 freed += journal->j_last - journal->j_first;
765 /* Update tail only if we free significant amount of space */
766 if (freed < journal->j_maxlen / 4)
767 update_tail = 0;
768 }
769 J_ASSERT(commit_transaction->t_state == T_COMMIT);
770 commit_transaction->t_state = T_COMMIT_DFLUSH;
771 write_unlock(&journal->j_state_lock);
772
773 /*
774 * If the journal is not located on the file system device,
775 * then we must flush the file system device before we issue
776 * the commit record
777 */
778 if (commit_transaction->t_need_data_flush &&
779 (journal->j_fs_dev != journal->j_dev) &&
780 (journal->j_flags & JBD2_BARRIER))
781 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
782
783 /* Done it all: now write the commit record asynchronously. */
784 if (jbd2_has_feature_async_commit(journal)) {
785 err = journal_submit_commit_record(journal, commit_transaction,
786 &cbh, crc32_sum);
787 if (err)
788 __jbd2_journal_abort_hard(journal);
789 }
790
791 blk_finish_plug(&plug);
792
793 /* Lo and behold: we have just managed to send a transaction to
794 the log. Before we can commit it, wait for the IO so far to
795 complete. Control buffers being written are on the
796 transaction's t_log_list queue, and metadata buffers are on
797 the io_bufs list.
798
799 Wait for the buffers in reverse order. That way we are
800 less likely to be woken up until all IOs have completed, and
801 so we incur less scheduling load.
802 */
803
804 jbd_debug(3, "JBD2: commit phase 3\n");
805
806 while (!list_empty(&io_bufs)) {
807 struct buffer_head *bh = list_entry(io_bufs.prev,
808 struct buffer_head,
809 b_assoc_buffers);
810
811 wait_on_buffer(bh);
812 cond_resched();
813
814 if (unlikely(!buffer_uptodate(bh)))
815 err = -EIO;
816 jbd2_unfile_log_bh(bh);
817
818 /*
819 * The list contains temporary buffer heads created by
820 * jbd2_journal_write_metadata_buffer().
821 */
822 BUFFER_TRACE(bh, "dumping temporary bh");
823 __brelse(bh);
824 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
825 free_buffer_head(bh);
826
827 /* We also have to refile the corresponding shadowed buffer */
828 jh = commit_transaction->t_shadow_list->b_tprev;
829 bh = jh2bh(jh);
830 clear_buffer_jwrite(bh);
831 J_ASSERT_BH(bh, buffer_jbddirty(bh));
832 J_ASSERT_BH(bh, !buffer_shadow(bh));
833
834 /* The metadata is now released for reuse, but we need
835 to remember it against this transaction so that when
836 we finally commit, we can do any checkpointing
837 required. */
838 JBUFFER_TRACE(jh, "file as BJ_Forget");
839 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
840 JBUFFER_TRACE(jh, "brelse shadowed buffer");
841 __brelse(bh);
842 }
843
844 J_ASSERT (commit_transaction->t_shadow_list == NULL);
845
846 jbd_debug(3, "JBD2: commit phase 4\n");
847
848 /* Here we wait for the revoke record and descriptor record buffers */
849 while (!list_empty(&log_bufs)) {
850 struct buffer_head *bh;
851
852 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
853 wait_on_buffer(bh);
854 cond_resched();
855
856 if (unlikely(!buffer_uptodate(bh)))
857 err = -EIO;
858
859 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
860 clear_buffer_jwrite(bh);
861 jbd2_unfile_log_bh(bh);
862 __brelse(bh); /* One for getblk */
863 /* AKPM: bforget here */
864 }
865
866 if (err)
867 jbd2_journal_abort(journal, err);
868
869 jbd_debug(3, "JBD2: commit phase 5\n");
870 write_lock(&journal->j_state_lock);
871 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
872 commit_transaction->t_state = T_COMMIT_JFLUSH;
873 write_unlock(&journal->j_state_lock);
874
875 if (!jbd2_has_feature_async_commit(journal)) {
876 err = journal_submit_commit_record(journal, commit_transaction,
877 &cbh, crc32_sum);
878 if (err)
879 __jbd2_journal_abort_hard(journal);
880 }
881 if (cbh)
882 err = journal_wait_on_commit_record(journal, cbh);
883 if (jbd2_has_feature_async_commit(journal) &&
884 journal->j_flags & JBD2_BARRIER) {
885 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
886 }
887
888 if (err)
889 jbd2_journal_abort(journal, err);
890
891 /*
892 * Now disk caches for filesystem device are flushed so we are safe to
893 * erase checkpointed transactions from the log by updating journal
894 * superblock.
895 */
896 if (update_tail)
897 jbd2_update_log_tail(journal, first_tid, first_block);
898
899 /* End of a transaction! Finally, we can do checkpoint
900 processing: any buffers committed as a result of this
901 transaction can be removed from any checkpoint list it was on
902 before. */
903
904 jbd_debug(3, "JBD2: commit phase 6\n");
905
906 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
907 J_ASSERT(commit_transaction->t_buffers == NULL);
908 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
909 J_ASSERT(commit_transaction->t_shadow_list == NULL);
910
911restart_loop:
912 /*
913 * As there are other places (journal_unmap_buffer()) adding buffers
914 * to this list we have to be careful and hold the j_list_lock.
915 */
916 spin_lock(&journal->j_list_lock);
917 while (commit_transaction->t_forget) {
918 transaction_t *cp_transaction;
919 struct buffer_head *bh;
920 int try_to_free = 0;
921
922 jh = commit_transaction->t_forget;
923 spin_unlock(&journal->j_list_lock);
924 bh = jh2bh(jh);
925 /*
926 * Get a reference so that bh cannot be freed before we are
927 * done with it.
928 */
929 get_bh(bh);
930 jbd_lock_bh_state(bh);
931 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
932
933 /*
934 * If there is undo-protected committed data against
935 * this buffer, then we can remove it now. If it is a
936 * buffer needing such protection, the old frozen_data
937 * field now points to a committed version of the
938 * buffer, so rotate that field to the new committed
939 * data.
940 *
941 * Otherwise, we can just throw away the frozen data now.
942 *
943 * We also know that the frozen data has already fired
944 * its triggers if they exist, so we can clear that too.
945 */
946 if (jh->b_committed_data) {
947 jbd2_free(jh->b_committed_data, bh->b_size);
948 jh->b_committed_data = NULL;
949 if (jh->b_frozen_data) {
950 jh->b_committed_data = jh->b_frozen_data;
951 jh->b_frozen_data = NULL;
952 jh->b_frozen_triggers = NULL;
953 }
954 } else if (jh->b_frozen_data) {
955 jbd2_free(jh->b_frozen_data, bh->b_size);
956 jh->b_frozen_data = NULL;
957 jh->b_frozen_triggers = NULL;
958 }
959
960 spin_lock(&journal->j_list_lock);
961 cp_transaction = jh->b_cp_transaction;
962 if (cp_transaction) {
963 JBUFFER_TRACE(jh, "remove from old cp transaction");
964 cp_transaction->t_chp_stats.cs_dropped++;
965 __jbd2_journal_remove_checkpoint(jh);
966 }
967
968 /* Only re-checkpoint the buffer_head if it is marked
969 * dirty. If the buffer was added to the BJ_Forget list
970 * by jbd2_journal_forget, it may no longer be dirty and
971 * there's no point in keeping a checkpoint record for
972 * it. */
973
974 /*
975 * A buffer which has been freed while still being journaled by
976 * a previous transaction.
977 */
978 if (buffer_freed(bh)) {
979 /*
980 * If the running transaction is the one containing
981 * "add to orphan" operation (b_next_transaction !=
982 * NULL), we have to wait for that transaction to
983 * commit before we can really get rid of the buffer.
984 * So just clear b_modified to not confuse transaction
985 * credit accounting and refile the buffer to
986 * BJ_Forget of the running transaction. If the just
987 * committed transaction contains "add to orphan"
988 * operation, we can completely invalidate the buffer
989 * now. We are rather through in that since the
990 * buffer may be still accessible when blocksize <
991 * pagesize and it is attached to the last partial
992 * page.
993 */
994 jh->b_modified = 0;
995 if (!jh->b_next_transaction) {
996 clear_buffer_freed(bh);
997 clear_buffer_jbddirty(bh);
998 clear_buffer_mapped(bh);
999 clear_buffer_new(bh);
1000 clear_buffer_req(bh);
1001 bh->b_bdev = NULL;
1002 }
1003 }
1004
1005 if (buffer_jbddirty(bh)) {
1006 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1007 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1008 if (is_journal_aborted(journal))
1009 clear_buffer_jbddirty(bh);
1010 } else {
1011 J_ASSERT_BH(bh, !buffer_dirty(bh));
1012 /*
1013 * The buffer on BJ_Forget list and not jbddirty means
1014 * it has been freed by this transaction and hence it
1015 * could not have been reallocated until this
1016 * transaction has committed. *BUT* it could be
1017 * reallocated once we have written all the data to
1018 * disk and before we process the buffer on BJ_Forget
1019 * list.
1020 */
1021 if (!jh->b_next_transaction)
1022 try_to_free = 1;
1023 }
1024 JBUFFER_TRACE(jh, "refile or unfile buffer");
1025 __jbd2_journal_refile_buffer(jh);
1026 jbd_unlock_bh_state(bh);
1027 if (try_to_free)
1028 release_buffer_page(bh); /* Drops bh reference */
1029 else
1030 __brelse(bh);
1031 cond_resched_lock(&journal->j_list_lock);
1032 }
1033 spin_unlock(&journal->j_list_lock);
1034 /*
1035 * This is a bit sleazy. We use j_list_lock to protect transition
1036 * of a transaction into T_FINISHED state and calling
1037 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1038 * other checkpointing code processing the transaction...
1039 */
1040 write_lock(&journal->j_state_lock);
1041 spin_lock(&journal->j_list_lock);
1042 /*
1043 * Now recheck if some buffers did not get attached to the transaction
1044 * while the lock was dropped...
1045 */
1046 if (commit_transaction->t_forget) {
1047 spin_unlock(&journal->j_list_lock);
1048 write_unlock(&journal->j_state_lock);
1049 goto restart_loop;
1050 }
1051
1052 /* Add the transaction to the checkpoint list
1053 * __journal_remove_checkpoint() can not destroy transaction
1054 * under us because it is not marked as T_FINISHED yet */
1055 if (journal->j_checkpoint_transactions == NULL) {
1056 journal->j_checkpoint_transactions = commit_transaction;
1057 commit_transaction->t_cpnext = commit_transaction;
1058 commit_transaction->t_cpprev = commit_transaction;
1059 } else {
1060 commit_transaction->t_cpnext =
1061 journal->j_checkpoint_transactions;
1062 commit_transaction->t_cpprev =
1063 commit_transaction->t_cpnext->t_cpprev;
1064 commit_transaction->t_cpnext->t_cpprev =
1065 commit_transaction;
1066 commit_transaction->t_cpprev->t_cpnext =
1067 commit_transaction;
1068 }
1069 spin_unlock(&journal->j_list_lock);
1070
1071 /* Done with this transaction! */
1072
1073 jbd_debug(3, "JBD2: commit phase 7\n");
1074
1075 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1076
1077 commit_transaction->t_start = jiffies;
1078 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1079 commit_transaction->t_start);
1080
1081 /*
1082 * File the transaction statistics
1083 */
1084 stats.ts_tid = commit_transaction->t_tid;
1085 stats.run.rs_handle_count =
1086 atomic_read(&commit_transaction->t_handle_count);
1087 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1088 commit_transaction->t_tid, &stats.run);
1089 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1090
1091 commit_transaction->t_state = T_COMMIT_CALLBACK;
1092 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1093 journal->j_commit_sequence = commit_transaction->t_tid;
1094 journal->j_committing_transaction = NULL;
1095 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1096
1097 /*
1098 * weight the commit time higher than the average time so we don't
1099 * react too strongly to vast changes in the commit time
1100 */
1101 if (likely(journal->j_average_commit_time))
1102 journal->j_average_commit_time = (commit_time +
1103 journal->j_average_commit_time*3) / 4;
1104 else
1105 journal->j_average_commit_time = commit_time;
1106
1107 write_unlock(&journal->j_state_lock);
1108
1109 if (journal->j_commit_callback)
1110 journal->j_commit_callback(journal, commit_transaction);
1111
1112 trace_jbd2_end_commit(journal, commit_transaction);
1113 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1114 journal->j_commit_sequence, journal->j_tail_sequence);
1115
1116 write_lock(&journal->j_state_lock);
1117 spin_lock(&journal->j_list_lock);
1118 commit_transaction->t_state = T_FINISHED;
1119 /* Check if the transaction can be dropped now that we are finished */
1120 if (commit_transaction->t_checkpoint_list == NULL &&
1121 commit_transaction->t_checkpoint_io_list == NULL) {
1122 __jbd2_journal_drop_transaction(journal, commit_transaction);
1123 jbd2_journal_free_transaction(commit_transaction);
1124 }
1125 spin_unlock(&journal->j_list_lock);
1126 write_unlock(&journal->j_state_lock);
1127 wake_up(&journal->j_wait_done_commit);
1128
1129 /*
1130 * Calculate overall stats
1131 */
1132 spin_lock(&journal->j_history_lock);
1133 journal->j_stats.ts_tid++;
1134 journal->j_stats.ts_requested += stats.ts_requested;
1135 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1136 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1137 journal->j_stats.run.rs_running += stats.run.rs_running;
1138 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1139 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1140 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1141 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1142 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1143 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1144 spin_unlock(&journal->j_history_lock);
1145}