Loading...
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 = current_kernel_time64();
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 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
138 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
139
140 if (jbd2_has_feature_checksum(journal)) {
141 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
142 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
143 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
144 }
145 jbd2_commit_block_csum_set(journal, bh);
146
147 BUFFER_TRACE(bh, "submit commit block");
148 lock_buffer(bh);
149 clear_buffer_dirty(bh);
150 set_buffer_uptodate(bh);
151 bh->b_end_io = journal_end_buffer_io_sync;
152
153 if (journal->j_flags & JBD2_BARRIER &&
154 !jbd2_has_feature_async_commit(journal))
155 ret = submit_bh(REQ_OP_WRITE,
156 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
157 else
158 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
159
160 *cbh = bh;
161 return ret;
162}
163
164/*
165 * This function along with journal_submit_commit_record
166 * allows to write the commit record asynchronously.
167 */
168static int journal_wait_on_commit_record(journal_t *journal,
169 struct buffer_head *bh)
170{
171 int ret = 0;
172
173 clear_buffer_dirty(bh);
174 wait_on_buffer(bh);
175
176 if (unlikely(!buffer_uptodate(bh)))
177 ret = -EIO;
178 put_bh(bh); /* One for getblk() */
179
180 return ret;
181}
182
183/*
184 * write the filemap data using writepage() address_space_operations.
185 * We don't do block allocation here even for delalloc. We don't
186 * use writepages() because with dealyed allocation we may be doing
187 * block allocation in writepages().
188 */
189static int journal_submit_inode_data_buffers(struct address_space *mapping)
190{
191 int ret;
192 struct writeback_control wbc = {
193 .sync_mode = WB_SYNC_ALL,
194 .nr_to_write = mapping->nrpages * 2,
195 .range_start = 0,
196 .range_end = i_size_read(mapping->host),
197 };
198
199 ret = generic_writepages(mapping, &wbc);
200 return ret;
201}
202
203/*
204 * Submit all the data buffers of inode associated with the transaction to
205 * disk.
206 *
207 * We are in a committing transaction. Therefore no new inode can be added to
208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
209 * operate on from being released while we write out pages.
210 */
211static int journal_submit_data_buffers(journal_t *journal,
212 transaction_t *commit_transaction)
213{
214 struct jbd2_inode *jinode;
215 int err, ret = 0;
216 struct address_space *mapping;
217
218 spin_lock(&journal->j_list_lock);
219 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
220 if (!(jinode->i_flags & JI_WRITE_DATA))
221 continue;
222 mapping = jinode->i_vfs_inode->i_mapping;
223 jinode->i_flags |= JI_COMMIT_RUNNING;
224 spin_unlock(&journal->j_list_lock);
225 /*
226 * submit the inode data buffers. We use writepage
227 * instead of writepages. Because writepages can do
228 * block allocation with delalloc. We need to write
229 * only allocated blocks here.
230 */
231 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
232 err = journal_submit_inode_data_buffers(mapping);
233 if (!ret)
234 ret = err;
235 spin_lock(&journal->j_list_lock);
236 J_ASSERT(jinode->i_transaction == commit_transaction);
237 jinode->i_flags &= ~JI_COMMIT_RUNNING;
238 smp_mb();
239 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
240 }
241 spin_unlock(&journal->j_list_lock);
242 return ret;
243}
244
245/*
246 * Wait for data submitted for writeout, refile inodes to proper
247 * transaction if needed.
248 *
249 */
250static int journal_finish_inode_data_buffers(journal_t *journal,
251 transaction_t *commit_transaction)
252{
253 struct jbd2_inode *jinode, *next_i;
254 int err, ret = 0;
255
256 /* For locking, see the comment in journal_submit_data_buffers() */
257 spin_lock(&journal->j_list_lock);
258 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
259 if (!(jinode->i_flags & JI_WAIT_DATA))
260 continue;
261 jinode->i_flags |= JI_COMMIT_RUNNING;
262 spin_unlock(&journal->j_list_lock);
263 err = filemap_fdatawait_keep_errors(
264 jinode->i_vfs_inode->i_mapping);
265 if (!ret)
266 ret = err;
267 spin_lock(&journal->j_list_lock);
268 jinode->i_flags &= ~JI_COMMIT_RUNNING;
269 smp_mb();
270 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
271 }
272
273 /* Now refile inode to proper lists */
274 list_for_each_entry_safe(jinode, next_i,
275 &commit_transaction->t_inode_list, i_list) {
276 list_del(&jinode->i_list);
277 if (jinode->i_next_transaction) {
278 jinode->i_transaction = jinode->i_next_transaction;
279 jinode->i_next_transaction = NULL;
280 list_add(&jinode->i_list,
281 &jinode->i_transaction->t_inode_list);
282 } else {
283 jinode->i_transaction = NULL;
284 }
285 }
286 spin_unlock(&journal->j_list_lock);
287
288 return ret;
289}
290
291static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
292{
293 struct page *page = bh->b_page;
294 char *addr;
295 __u32 checksum;
296
297 addr = kmap_atomic(page);
298 checksum = crc32_be(crc32_sum,
299 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
300 kunmap_atomic(addr);
301
302 return checksum;
303}
304
305static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
306 unsigned long long block)
307{
308 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
309 if (jbd2_has_feature_64bit(j))
310 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
311}
312
313static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
314 struct buffer_head *bh, __u32 sequence)
315{
316 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
317 struct page *page = bh->b_page;
318 __u8 *addr;
319 __u32 csum32;
320 __be32 seq;
321
322 if (!jbd2_journal_has_csum_v2or3(j))
323 return;
324
325 seq = cpu_to_be32(sequence);
326 addr = kmap_atomic(page);
327 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
328 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
329 bh->b_size);
330 kunmap_atomic(addr);
331
332 if (jbd2_has_feature_csum3(j))
333 tag3->t_checksum = cpu_to_be32(csum32);
334 else
335 tag->t_checksum = cpu_to_be16(csum32);
336}
337/*
338 * jbd2_journal_commit_transaction
339 *
340 * The primary function for committing a transaction to the log. This
341 * function is called by the journal thread to begin a complete commit.
342 */
343void jbd2_journal_commit_transaction(journal_t *journal)
344{
345 struct transaction_stats_s stats;
346 transaction_t *commit_transaction;
347 struct journal_head *jh;
348 struct buffer_head *descriptor;
349 struct buffer_head **wbuf = journal->j_wbuf;
350 int bufs;
351 int flags;
352 int err;
353 unsigned long long blocknr;
354 ktime_t start_time;
355 u64 commit_time;
356 char *tagp = NULL;
357 journal_block_tag_t *tag = NULL;
358 int space_left = 0;
359 int first_tag = 0;
360 int tag_flag;
361 int i;
362 int tag_bytes = journal_tag_bytes(journal);
363 struct buffer_head *cbh = NULL; /* For transactional checksums */
364 __u32 crc32_sum = ~0;
365 struct blk_plug plug;
366 /* Tail of the journal */
367 unsigned long first_block;
368 tid_t first_tid;
369 int update_tail;
370 int csum_size = 0;
371 LIST_HEAD(io_bufs);
372 LIST_HEAD(log_bufs);
373
374 if (jbd2_journal_has_csum_v2or3(journal))
375 csum_size = sizeof(struct jbd2_journal_block_tail);
376
377 /*
378 * First job: lock down the current transaction and wait for
379 * all outstanding updates to complete.
380 */
381
382 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
383 if (journal->j_flags & JBD2_FLUSHED) {
384 jbd_debug(3, "super block updated\n");
385 mutex_lock_io(&journal->j_checkpoint_mutex);
386 /*
387 * We hold j_checkpoint_mutex so tail cannot change under us.
388 * We don't need any special data guarantees for writing sb
389 * since journal is empty and it is ok for write to be
390 * flushed only with transaction commit.
391 */
392 jbd2_journal_update_sb_log_tail(journal,
393 journal->j_tail_sequence,
394 journal->j_tail,
395 REQ_SYNC);
396 mutex_unlock(&journal->j_checkpoint_mutex);
397 } else {
398 jbd_debug(3, "superblock not updated\n");
399 }
400
401 J_ASSERT(journal->j_running_transaction != NULL);
402 J_ASSERT(journal->j_committing_transaction == NULL);
403
404 commit_transaction = journal->j_running_transaction;
405
406 trace_jbd2_start_commit(journal, commit_transaction);
407 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
408 commit_transaction->t_tid);
409
410 write_lock(&journal->j_state_lock);
411 J_ASSERT(commit_transaction->t_state == T_RUNNING);
412 commit_transaction->t_state = T_LOCKED;
413
414 trace_jbd2_commit_locking(journal, commit_transaction);
415 stats.run.rs_wait = commit_transaction->t_max_wait;
416 stats.run.rs_request_delay = 0;
417 stats.run.rs_locked = jiffies;
418 if (commit_transaction->t_requested)
419 stats.run.rs_request_delay =
420 jbd2_time_diff(commit_transaction->t_requested,
421 stats.run.rs_locked);
422 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
423 stats.run.rs_locked);
424
425 spin_lock(&commit_transaction->t_handle_lock);
426 while (atomic_read(&commit_transaction->t_updates)) {
427 DEFINE_WAIT(wait);
428
429 prepare_to_wait(&journal->j_wait_updates, &wait,
430 TASK_UNINTERRUPTIBLE);
431 if (atomic_read(&commit_transaction->t_updates)) {
432 spin_unlock(&commit_transaction->t_handle_lock);
433 write_unlock(&journal->j_state_lock);
434 schedule();
435 write_lock(&journal->j_state_lock);
436 spin_lock(&commit_transaction->t_handle_lock);
437 }
438 finish_wait(&journal->j_wait_updates, &wait);
439 }
440 spin_unlock(&commit_transaction->t_handle_lock);
441
442 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
443 journal->j_max_transaction_buffers);
444
445 /*
446 * First thing we are allowed to do is to discard any remaining
447 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
448 * that there are no such buffers: if a large filesystem
449 * operation like a truncate needs to split itself over multiple
450 * transactions, then it may try to do a jbd2_journal_restart() while
451 * there are still BJ_Reserved buffers outstanding. These must
452 * be released cleanly from the current transaction.
453 *
454 * In this case, the filesystem must still reserve write access
455 * again before modifying the buffer in the new transaction, but
456 * we do not require it to remember exactly which old buffers it
457 * has reserved. This is consistent with the existing behaviour
458 * that multiple jbd2_journal_get_write_access() calls to the same
459 * buffer are perfectly permissible.
460 */
461 while (commit_transaction->t_reserved_list) {
462 jh = commit_transaction->t_reserved_list;
463 JBUFFER_TRACE(jh, "reserved, unused: refile");
464 /*
465 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
466 * leave undo-committed data.
467 */
468 if (jh->b_committed_data) {
469 struct buffer_head *bh = jh2bh(jh);
470
471 jbd_lock_bh_state(bh);
472 jbd2_free(jh->b_committed_data, bh->b_size);
473 jh->b_committed_data = NULL;
474 jbd_unlock_bh_state(bh);
475 }
476 jbd2_journal_refile_buffer(journal, jh);
477 }
478
479 /*
480 * Now try to drop any written-back buffers from the journal's
481 * checkpoint lists. We do this *before* commit because it potentially
482 * frees some memory
483 */
484 spin_lock(&journal->j_list_lock);
485 __jbd2_journal_clean_checkpoint_list(journal, false);
486 spin_unlock(&journal->j_list_lock);
487
488 jbd_debug(3, "JBD2: commit phase 1\n");
489
490 /*
491 * Clear revoked flag to reflect there is no revoked buffers
492 * in the next transaction which is going to be started.
493 */
494 jbd2_clear_buffer_revoked_flags(journal);
495
496 /*
497 * Switch to a new revoke table.
498 */
499 jbd2_journal_switch_revoke_table(journal);
500
501 /*
502 * Reserved credits cannot be claimed anymore, free them
503 */
504 atomic_sub(atomic_read(&journal->j_reserved_credits),
505 &commit_transaction->t_outstanding_credits);
506
507 trace_jbd2_commit_flushing(journal, commit_transaction);
508 stats.run.rs_flushing = jiffies;
509 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
510 stats.run.rs_flushing);
511
512 commit_transaction->t_state = T_FLUSH;
513 journal->j_committing_transaction = commit_transaction;
514 journal->j_running_transaction = NULL;
515 start_time = ktime_get();
516 commit_transaction->t_log_start = journal->j_head;
517 wake_up(&journal->j_wait_transaction_locked);
518 write_unlock(&journal->j_state_lock);
519
520 jbd_debug(3, "JBD2: commit phase 2a\n");
521
522 /*
523 * Now start flushing things to disk, in the order they appear
524 * on the transaction lists. Data blocks go first.
525 */
526 err = journal_submit_data_buffers(journal, commit_transaction);
527 if (err)
528 jbd2_journal_abort(journal, err);
529
530 blk_start_plug(&plug);
531 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
532
533 jbd_debug(3, "JBD2: commit phase 2b\n");
534
535 /*
536 * Way to go: we have now written out all of the data for a
537 * transaction! Now comes the tricky part: we need to write out
538 * metadata. Loop over the transaction's entire buffer list:
539 */
540 write_lock(&journal->j_state_lock);
541 commit_transaction->t_state = T_COMMIT;
542 write_unlock(&journal->j_state_lock);
543
544 trace_jbd2_commit_logging(journal, commit_transaction);
545 stats.run.rs_logging = jiffies;
546 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
547 stats.run.rs_logging);
548 stats.run.rs_blocks =
549 atomic_read(&commit_transaction->t_outstanding_credits);
550 stats.run.rs_blocks_logged = 0;
551
552 J_ASSERT(commit_transaction->t_nr_buffers <=
553 atomic_read(&commit_transaction->t_outstanding_credits));
554
555 err = 0;
556 bufs = 0;
557 descriptor = NULL;
558 while (commit_transaction->t_buffers) {
559
560 /* Find the next buffer to be journaled... */
561
562 jh = commit_transaction->t_buffers;
563
564 /* If we're in abort mode, we just un-journal the buffer and
565 release it. */
566
567 if (is_journal_aborted(journal)) {
568 clear_buffer_jbddirty(jh2bh(jh));
569 JBUFFER_TRACE(jh, "journal is aborting: refile");
570 jbd2_buffer_abort_trigger(jh,
571 jh->b_frozen_data ?
572 jh->b_frozen_triggers :
573 jh->b_triggers);
574 jbd2_journal_refile_buffer(journal, jh);
575 /* If that was the last one, we need to clean up
576 * any descriptor buffers which may have been
577 * already allocated, even if we are now
578 * aborting. */
579 if (!commit_transaction->t_buffers)
580 goto start_journal_io;
581 continue;
582 }
583
584 /* Make sure we have a descriptor block in which to
585 record the metadata buffer. */
586
587 if (!descriptor) {
588 J_ASSERT (bufs == 0);
589
590 jbd_debug(4, "JBD2: get descriptor\n");
591
592 descriptor = jbd2_journal_get_descriptor_buffer(
593 commit_transaction,
594 JBD2_DESCRIPTOR_BLOCK);
595 if (!descriptor) {
596 jbd2_journal_abort(journal, -EIO);
597 continue;
598 }
599
600 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
601 (unsigned long long)descriptor->b_blocknr,
602 descriptor->b_data);
603 tagp = &descriptor->b_data[sizeof(journal_header_t)];
604 space_left = descriptor->b_size -
605 sizeof(journal_header_t);
606 first_tag = 1;
607 set_buffer_jwrite(descriptor);
608 set_buffer_dirty(descriptor);
609 wbuf[bufs++] = descriptor;
610
611 /* Record it so that we can wait for IO
612 completion later */
613 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
614 jbd2_file_log_bh(&log_bufs, descriptor);
615 }
616
617 /* Where is the buffer to be written? */
618
619 err = jbd2_journal_next_log_block(journal, &blocknr);
620 /* If the block mapping failed, just abandon the buffer
621 and repeat this loop: we'll fall into the
622 refile-on-abort condition above. */
623 if (err) {
624 jbd2_journal_abort(journal, err);
625 continue;
626 }
627
628 /*
629 * start_this_handle() uses t_outstanding_credits to determine
630 * the free space in the log, but this counter is changed
631 * by jbd2_journal_next_log_block() also.
632 */
633 atomic_dec(&commit_transaction->t_outstanding_credits);
634
635 /* Bump b_count to prevent truncate from stumbling over
636 the shadowed buffer! @@@ This can go if we ever get
637 rid of the shadow pairing of buffers. */
638 atomic_inc(&jh2bh(jh)->b_count);
639
640 /*
641 * Make a temporary IO buffer with which to write it out
642 * (this will requeue the metadata buffer to BJ_Shadow).
643 */
644 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
645 JBUFFER_TRACE(jh, "ph3: write metadata");
646 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
647 jh, &wbuf[bufs], blocknr);
648 if (flags < 0) {
649 jbd2_journal_abort(journal, flags);
650 continue;
651 }
652 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
653
654 /* Record the new block's tag in the current descriptor
655 buffer */
656
657 tag_flag = 0;
658 if (flags & 1)
659 tag_flag |= JBD2_FLAG_ESCAPE;
660 if (!first_tag)
661 tag_flag |= JBD2_FLAG_SAME_UUID;
662
663 tag = (journal_block_tag_t *) tagp;
664 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
665 tag->t_flags = cpu_to_be16(tag_flag);
666 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
667 commit_transaction->t_tid);
668 tagp += tag_bytes;
669 space_left -= tag_bytes;
670 bufs++;
671
672 if (first_tag) {
673 memcpy (tagp, journal->j_uuid, 16);
674 tagp += 16;
675 space_left -= 16;
676 first_tag = 0;
677 }
678
679 /* If there's no more to do, or if the descriptor is full,
680 let the IO rip! */
681
682 if (bufs == journal->j_wbufsize ||
683 commit_transaction->t_buffers == NULL ||
684 space_left < tag_bytes + 16 + csum_size) {
685
686 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
687
688 /* Write an end-of-descriptor marker before
689 submitting the IOs. "tag" still points to
690 the last tag we set up. */
691
692 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
693
694 jbd2_descriptor_block_csum_set(journal, descriptor);
695start_journal_io:
696 for (i = 0; i < bufs; i++) {
697 struct buffer_head *bh = wbuf[i];
698 /*
699 * Compute checksum.
700 */
701 if (jbd2_has_feature_checksum(journal)) {
702 crc32_sum =
703 jbd2_checksum_data(crc32_sum, bh);
704 }
705
706 lock_buffer(bh);
707 clear_buffer_dirty(bh);
708 set_buffer_uptodate(bh);
709 bh->b_end_io = journal_end_buffer_io_sync;
710 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
711 }
712 cond_resched();
713 stats.run.rs_blocks_logged += bufs;
714
715 /* Force a new descriptor to be generated next
716 time round the loop. */
717 descriptor = NULL;
718 bufs = 0;
719 }
720 }
721
722 err = journal_finish_inode_data_buffers(journal, commit_transaction);
723 if (err) {
724 printk(KERN_WARNING
725 "JBD2: Detected IO errors while flushing file data "
726 "on %s\n", journal->j_devname);
727 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
728 jbd2_journal_abort(journal, err);
729 err = 0;
730 }
731
732 /*
733 * Get current oldest transaction in the log before we issue flush
734 * to the filesystem device. After the flush we can be sure that
735 * blocks of all older transactions are checkpointed to persistent
736 * storage and we will be safe to update journal start in the
737 * superblock with the numbers we get here.
738 */
739 update_tail =
740 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
741
742 write_lock(&journal->j_state_lock);
743 if (update_tail) {
744 long freed = first_block - journal->j_tail;
745
746 if (first_block < journal->j_tail)
747 freed += journal->j_last - journal->j_first;
748 /* Update tail only if we free significant amount of space */
749 if (freed < journal->j_maxlen / 4)
750 update_tail = 0;
751 }
752 J_ASSERT(commit_transaction->t_state == T_COMMIT);
753 commit_transaction->t_state = T_COMMIT_DFLUSH;
754 write_unlock(&journal->j_state_lock);
755
756 /*
757 * If the journal is not located on the file system device,
758 * then we must flush the file system device before we issue
759 * the commit record
760 */
761 if (commit_transaction->t_need_data_flush &&
762 (journal->j_fs_dev != journal->j_dev) &&
763 (journal->j_flags & JBD2_BARRIER))
764 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
765
766 /* Done it all: now write the commit record asynchronously. */
767 if (jbd2_has_feature_async_commit(journal)) {
768 err = journal_submit_commit_record(journal, commit_transaction,
769 &cbh, crc32_sum);
770 if (err)
771 __jbd2_journal_abort_hard(journal);
772 }
773
774 blk_finish_plug(&plug);
775
776 /* Lo and behold: we have just managed to send a transaction to
777 the log. Before we can commit it, wait for the IO so far to
778 complete. Control buffers being written are on the
779 transaction's t_log_list queue, and metadata buffers are on
780 the io_bufs list.
781
782 Wait for the buffers in reverse order. That way we are
783 less likely to be woken up until all IOs have completed, and
784 so we incur less scheduling load.
785 */
786
787 jbd_debug(3, "JBD2: commit phase 3\n");
788
789 while (!list_empty(&io_bufs)) {
790 struct buffer_head *bh = list_entry(io_bufs.prev,
791 struct buffer_head,
792 b_assoc_buffers);
793
794 wait_on_buffer(bh);
795 cond_resched();
796
797 if (unlikely(!buffer_uptodate(bh)))
798 err = -EIO;
799 jbd2_unfile_log_bh(bh);
800
801 /*
802 * The list contains temporary buffer heads created by
803 * jbd2_journal_write_metadata_buffer().
804 */
805 BUFFER_TRACE(bh, "dumping temporary bh");
806 __brelse(bh);
807 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
808 free_buffer_head(bh);
809
810 /* We also have to refile the corresponding shadowed buffer */
811 jh = commit_transaction->t_shadow_list->b_tprev;
812 bh = jh2bh(jh);
813 clear_buffer_jwrite(bh);
814 J_ASSERT_BH(bh, buffer_jbddirty(bh));
815 J_ASSERT_BH(bh, !buffer_shadow(bh));
816
817 /* The metadata is now released for reuse, but we need
818 to remember it against this transaction so that when
819 we finally commit, we can do any checkpointing
820 required. */
821 JBUFFER_TRACE(jh, "file as BJ_Forget");
822 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
823 JBUFFER_TRACE(jh, "brelse shadowed buffer");
824 __brelse(bh);
825 }
826
827 J_ASSERT (commit_transaction->t_shadow_list == NULL);
828
829 jbd_debug(3, "JBD2: commit phase 4\n");
830
831 /* Here we wait for the revoke record and descriptor record buffers */
832 while (!list_empty(&log_bufs)) {
833 struct buffer_head *bh;
834
835 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
836 wait_on_buffer(bh);
837 cond_resched();
838
839 if (unlikely(!buffer_uptodate(bh)))
840 err = -EIO;
841
842 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
843 clear_buffer_jwrite(bh);
844 jbd2_unfile_log_bh(bh);
845 __brelse(bh); /* One for getblk */
846 /* AKPM: bforget here */
847 }
848
849 if (err)
850 jbd2_journal_abort(journal, err);
851
852 jbd_debug(3, "JBD2: commit phase 5\n");
853 write_lock(&journal->j_state_lock);
854 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
855 commit_transaction->t_state = T_COMMIT_JFLUSH;
856 write_unlock(&journal->j_state_lock);
857
858 if (!jbd2_has_feature_async_commit(journal)) {
859 err = journal_submit_commit_record(journal, commit_transaction,
860 &cbh, crc32_sum);
861 if (err)
862 __jbd2_journal_abort_hard(journal);
863 }
864 if (cbh)
865 err = journal_wait_on_commit_record(journal, cbh);
866 if (jbd2_has_feature_async_commit(journal) &&
867 journal->j_flags & JBD2_BARRIER) {
868 blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
869 }
870
871 if (err)
872 jbd2_journal_abort(journal, err);
873
874 /*
875 * Now disk caches for filesystem device are flushed so we are safe to
876 * erase checkpointed transactions from the log by updating journal
877 * superblock.
878 */
879 if (update_tail)
880 jbd2_update_log_tail(journal, first_tid, first_block);
881
882 /* End of a transaction! Finally, we can do checkpoint
883 processing: any buffers committed as a result of this
884 transaction can be removed from any checkpoint list it was on
885 before. */
886
887 jbd_debug(3, "JBD2: commit phase 6\n");
888
889 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
890 J_ASSERT(commit_transaction->t_buffers == NULL);
891 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
892 J_ASSERT(commit_transaction->t_shadow_list == NULL);
893
894restart_loop:
895 /*
896 * As there are other places (journal_unmap_buffer()) adding buffers
897 * to this list we have to be careful and hold the j_list_lock.
898 */
899 spin_lock(&journal->j_list_lock);
900 while (commit_transaction->t_forget) {
901 transaction_t *cp_transaction;
902 struct buffer_head *bh;
903 int try_to_free = 0;
904
905 jh = commit_transaction->t_forget;
906 spin_unlock(&journal->j_list_lock);
907 bh = jh2bh(jh);
908 /*
909 * Get a reference so that bh cannot be freed before we are
910 * done with it.
911 */
912 get_bh(bh);
913 jbd_lock_bh_state(bh);
914 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
915
916 /*
917 * If there is undo-protected committed data against
918 * this buffer, then we can remove it now. If it is a
919 * buffer needing such protection, the old frozen_data
920 * field now points to a committed version of the
921 * buffer, so rotate that field to the new committed
922 * data.
923 *
924 * Otherwise, we can just throw away the frozen data now.
925 *
926 * We also know that the frozen data has already fired
927 * its triggers if they exist, so we can clear that too.
928 */
929 if (jh->b_committed_data) {
930 jbd2_free(jh->b_committed_data, bh->b_size);
931 jh->b_committed_data = NULL;
932 if (jh->b_frozen_data) {
933 jh->b_committed_data = jh->b_frozen_data;
934 jh->b_frozen_data = NULL;
935 jh->b_frozen_triggers = NULL;
936 }
937 } else if (jh->b_frozen_data) {
938 jbd2_free(jh->b_frozen_data, bh->b_size);
939 jh->b_frozen_data = NULL;
940 jh->b_frozen_triggers = NULL;
941 }
942
943 spin_lock(&journal->j_list_lock);
944 cp_transaction = jh->b_cp_transaction;
945 if (cp_transaction) {
946 JBUFFER_TRACE(jh, "remove from old cp transaction");
947 cp_transaction->t_chp_stats.cs_dropped++;
948 __jbd2_journal_remove_checkpoint(jh);
949 }
950
951 /* Only re-checkpoint the buffer_head if it is marked
952 * dirty. If the buffer was added to the BJ_Forget list
953 * by jbd2_journal_forget, it may no longer be dirty and
954 * there's no point in keeping a checkpoint record for
955 * it. */
956
957 /*
958 * A buffer which has been freed while still being journaled by
959 * a previous transaction.
960 */
961 if (buffer_freed(bh)) {
962 /*
963 * If the running transaction is the one containing
964 * "add to orphan" operation (b_next_transaction !=
965 * NULL), we have to wait for that transaction to
966 * commit before we can really get rid of the buffer.
967 * So just clear b_modified to not confuse transaction
968 * credit accounting and refile the buffer to
969 * BJ_Forget of the running transaction. If the just
970 * committed transaction contains "add to orphan"
971 * operation, we can completely invalidate the buffer
972 * now. We are rather through in that since the
973 * buffer may be still accessible when blocksize <
974 * pagesize and it is attached to the last partial
975 * page.
976 */
977 jh->b_modified = 0;
978 if (!jh->b_next_transaction) {
979 clear_buffer_freed(bh);
980 clear_buffer_jbddirty(bh);
981 clear_buffer_mapped(bh);
982 clear_buffer_new(bh);
983 clear_buffer_req(bh);
984 bh->b_bdev = NULL;
985 }
986 }
987
988 if (buffer_jbddirty(bh)) {
989 JBUFFER_TRACE(jh, "add to new checkpointing trans");
990 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
991 if (is_journal_aborted(journal))
992 clear_buffer_jbddirty(bh);
993 } else {
994 J_ASSERT_BH(bh, !buffer_dirty(bh));
995 /*
996 * The buffer on BJ_Forget list and not jbddirty means
997 * it has been freed by this transaction and hence it
998 * could not have been reallocated until this
999 * transaction has committed. *BUT* it could be
1000 * reallocated once we have written all the data to
1001 * disk and before we process the buffer on BJ_Forget
1002 * list.
1003 */
1004 if (!jh->b_next_transaction)
1005 try_to_free = 1;
1006 }
1007 JBUFFER_TRACE(jh, "refile or unfile buffer");
1008 __jbd2_journal_refile_buffer(jh);
1009 jbd_unlock_bh_state(bh);
1010 if (try_to_free)
1011 release_buffer_page(bh); /* Drops bh reference */
1012 else
1013 __brelse(bh);
1014 cond_resched_lock(&journal->j_list_lock);
1015 }
1016 spin_unlock(&journal->j_list_lock);
1017 /*
1018 * This is a bit sleazy. We use j_list_lock to protect transition
1019 * of a transaction into T_FINISHED state and calling
1020 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1021 * other checkpointing code processing the transaction...
1022 */
1023 write_lock(&journal->j_state_lock);
1024 spin_lock(&journal->j_list_lock);
1025 /*
1026 * Now recheck if some buffers did not get attached to the transaction
1027 * while the lock was dropped...
1028 */
1029 if (commit_transaction->t_forget) {
1030 spin_unlock(&journal->j_list_lock);
1031 write_unlock(&journal->j_state_lock);
1032 goto restart_loop;
1033 }
1034
1035 /* Add the transaction to the checkpoint list
1036 * __journal_remove_checkpoint() can not destroy transaction
1037 * under us because it is not marked as T_FINISHED yet */
1038 if (journal->j_checkpoint_transactions == NULL) {
1039 journal->j_checkpoint_transactions = commit_transaction;
1040 commit_transaction->t_cpnext = commit_transaction;
1041 commit_transaction->t_cpprev = commit_transaction;
1042 } else {
1043 commit_transaction->t_cpnext =
1044 journal->j_checkpoint_transactions;
1045 commit_transaction->t_cpprev =
1046 commit_transaction->t_cpnext->t_cpprev;
1047 commit_transaction->t_cpnext->t_cpprev =
1048 commit_transaction;
1049 commit_transaction->t_cpprev->t_cpnext =
1050 commit_transaction;
1051 }
1052 spin_unlock(&journal->j_list_lock);
1053
1054 /* Done with this transaction! */
1055
1056 jbd_debug(3, "JBD2: commit phase 7\n");
1057
1058 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1059
1060 commit_transaction->t_start = jiffies;
1061 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1062 commit_transaction->t_start);
1063
1064 /*
1065 * File the transaction statistics
1066 */
1067 stats.ts_tid = commit_transaction->t_tid;
1068 stats.run.rs_handle_count =
1069 atomic_read(&commit_transaction->t_handle_count);
1070 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1071 commit_transaction->t_tid, &stats.run);
1072 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1073
1074 commit_transaction->t_state = T_COMMIT_CALLBACK;
1075 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1076 journal->j_commit_sequence = commit_transaction->t_tid;
1077 journal->j_committing_transaction = NULL;
1078 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1079
1080 /*
1081 * weight the commit time higher than the average time so we don't
1082 * react too strongly to vast changes in the commit time
1083 */
1084 if (likely(journal->j_average_commit_time))
1085 journal->j_average_commit_time = (commit_time +
1086 journal->j_average_commit_time*3) / 4;
1087 else
1088 journal->j_average_commit_time = commit_time;
1089
1090 write_unlock(&journal->j_state_lock);
1091
1092 if (journal->j_commit_callback)
1093 journal->j_commit_callback(journal, commit_transaction);
1094
1095 trace_jbd2_end_commit(journal, commit_transaction);
1096 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1097 journal->j_commit_sequence, journal->j_tail_sequence);
1098
1099 write_lock(&journal->j_state_lock);
1100 spin_lock(&journal->j_list_lock);
1101 commit_transaction->t_state = T_FINISHED;
1102 /* Check if the transaction can be dropped now that we are finished */
1103 if (commit_transaction->t_checkpoint_list == NULL &&
1104 commit_transaction->t_checkpoint_io_list == NULL) {
1105 __jbd2_journal_drop_transaction(journal, commit_transaction);
1106 jbd2_journal_free_transaction(commit_transaction);
1107 }
1108 spin_unlock(&journal->j_list_lock);
1109 write_unlock(&journal->j_state_lock);
1110 wake_up(&journal->j_wait_done_commit);
1111
1112 /*
1113 * Calculate overall stats
1114 */
1115 spin_lock(&journal->j_history_lock);
1116 journal->j_stats.ts_tid++;
1117 journal->j_stats.ts_requested += stats.ts_requested;
1118 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1119 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1120 journal->j_stats.run.rs_running += stats.run.rs_running;
1121 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1122 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1123 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1124 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1125 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1126 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1127 spin_unlock(&journal->j_history_lock);
1128}
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 folio *folio;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 folio = bh->b_folio;
72 if (folio->mapping)
73 goto nope;
74
75 /* OK, it's a truncated page */
76 if (!folio_trylock(folio))
77 goto nope;
78
79 folio_get(folio);
80 __brelse(bh);
81 try_to_free_buffers(folio);
82 folio_unlock(folio);
83 folio_put(folio);
84 return;
85
86nope:
87 __brelse(bh);
88}
89
90static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
91{
92 struct commit_header *h;
93 __u32 csum;
94
95 if (!jbd2_journal_has_csum_v2or3(j))
96 return;
97
98 h = (struct commit_header *)(bh->b_data);
99 h->h_chksum_type = 0;
100 h->h_chksum_size = 0;
101 h->h_chksum[0] = 0;
102 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, 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 commit_header *tmp;
120 struct buffer_head *bh;
121 struct timespec64 now;
122 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
123
124 *cbh = NULL;
125
126 if (is_journal_aborted(journal))
127 return 0;
128
129 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
130 JBD2_COMMIT_BLOCK);
131 if (!bh)
132 return 1;
133
134 tmp = (struct commit_header *)bh->b_data;
135 ktime_get_coarse_real_ts64(&now);
136 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
137 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
138
139 if (jbd2_has_feature_checksum(journal)) {
140 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
141 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
142 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
143 }
144 jbd2_commit_block_csum_set(journal, bh);
145
146 BUFFER_TRACE(bh, "submit commit block");
147 lock_buffer(bh);
148 clear_buffer_dirty(bh);
149 set_buffer_uptodate(bh);
150 bh->b_end_io = journal_end_buffer_io_sync;
151
152 if (journal->j_flags & JBD2_BARRIER &&
153 !jbd2_has_feature_async_commit(journal))
154 write_flags |= REQ_PREFLUSH | REQ_FUA;
155
156 submit_bh(write_flags, bh);
157 *cbh = bh;
158 return 0;
159}
160
161/*
162 * This function along with journal_submit_commit_record
163 * allows to write the commit record asynchronously.
164 */
165static int journal_wait_on_commit_record(journal_t *journal,
166 struct buffer_head *bh)
167{
168 int ret = 0;
169
170 clear_buffer_dirty(bh);
171 wait_on_buffer(bh);
172
173 if (unlikely(!buffer_uptodate(bh)))
174 ret = -EIO;
175 put_bh(bh); /* One for getblk() */
176
177 return ret;
178}
179
180/* Send all the data buffers related to an inode */
181int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
182{
183 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
184 return 0;
185
186 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
187 return journal->j_submit_inode_data_buffers(jinode);
188
189}
190EXPORT_SYMBOL(jbd2_submit_inode_data);
191
192int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
193{
194 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
195 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
196 return 0;
197 return filemap_fdatawait_range_keep_errors(
198 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
199 jinode->i_dirty_end);
200}
201EXPORT_SYMBOL(jbd2_wait_inode_data);
202
203/*
204 * Submit all the data buffers of inode associated with the transaction to
205 * disk.
206 *
207 * We are in a committing transaction. Therefore no new inode can be added to
208 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
209 * operate on from being released while we write out pages.
210 */
211static int journal_submit_data_buffers(journal_t *journal,
212 transaction_t *commit_transaction)
213{
214 struct jbd2_inode *jinode;
215 int err, ret = 0;
216
217 spin_lock(&journal->j_list_lock);
218 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
219 if (!(jinode->i_flags & JI_WRITE_DATA))
220 continue;
221 jinode->i_flags |= JI_COMMIT_RUNNING;
222 spin_unlock(&journal->j_list_lock);
223 /* submit the inode data buffers. */
224 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
225 if (journal->j_submit_inode_data_buffers) {
226 err = journal->j_submit_inode_data_buffers(jinode);
227 if (!ret)
228 ret = err;
229 }
230 spin_lock(&journal->j_list_lock);
231 J_ASSERT(jinode->i_transaction == commit_transaction);
232 jinode->i_flags &= ~JI_COMMIT_RUNNING;
233 smp_mb();
234 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
235 }
236 spin_unlock(&journal->j_list_lock);
237 return ret;
238}
239
240int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
241{
242 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
243
244 return filemap_fdatawait_range_keep_errors(mapping,
245 jinode->i_dirty_start,
246 jinode->i_dirty_end);
247}
248
249/*
250 * Wait for data submitted for writeout, refile inodes to proper
251 * transaction if needed.
252 *
253 */
254static int journal_finish_inode_data_buffers(journal_t *journal,
255 transaction_t *commit_transaction)
256{
257 struct jbd2_inode *jinode, *next_i;
258 int err, ret = 0;
259
260 /* For locking, see the comment in journal_submit_data_buffers() */
261 spin_lock(&journal->j_list_lock);
262 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
263 if (!(jinode->i_flags & JI_WAIT_DATA))
264 continue;
265 jinode->i_flags |= JI_COMMIT_RUNNING;
266 spin_unlock(&journal->j_list_lock);
267 /* wait for the inode data buffers writeout. */
268 if (journal->j_finish_inode_data_buffers) {
269 err = journal->j_finish_inode_data_buffers(jinode);
270 if (!ret)
271 ret = err;
272 }
273 cond_resched();
274 spin_lock(&journal->j_list_lock);
275 jinode->i_flags &= ~JI_COMMIT_RUNNING;
276 smp_mb();
277 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
278 }
279
280 /* Now refile inode to proper lists */
281 list_for_each_entry_safe(jinode, next_i,
282 &commit_transaction->t_inode_list, i_list) {
283 list_del(&jinode->i_list);
284 if (jinode->i_next_transaction) {
285 jinode->i_transaction = jinode->i_next_transaction;
286 jinode->i_next_transaction = NULL;
287 list_add(&jinode->i_list,
288 &jinode->i_transaction->t_inode_list);
289 } else {
290 jinode->i_transaction = NULL;
291 jinode->i_dirty_start = 0;
292 jinode->i_dirty_end = 0;
293 }
294 }
295 spin_unlock(&journal->j_list_lock);
296
297 return ret;
298}
299
300static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
301{
302 char *addr;
303 __u32 checksum;
304
305 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
306 checksum = crc32_be(crc32_sum, addr, bh->b_size);
307 kunmap_local(addr);
308
309 return checksum;
310}
311
312static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
313 unsigned long long block)
314{
315 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
316 if (jbd2_has_feature_64bit(j))
317 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
318}
319
320static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
321 struct buffer_head *bh, __u32 sequence)
322{
323 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
324 __u8 *addr;
325 __u32 csum32;
326 __be32 seq;
327
328 if (!jbd2_journal_has_csum_v2or3(j))
329 return;
330
331 seq = cpu_to_be32(sequence);
332 addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
333 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
334 csum32 = jbd2_chksum(j, csum32, addr, bh->b_size);
335 kunmap_local(addr);
336
337 if (jbd2_has_feature_csum3(j))
338 tag3->t_checksum = cpu_to_be32(csum32);
339 else
340 tag->t_checksum = cpu_to_be16(csum32);
341}
342/*
343 * jbd2_journal_commit_transaction
344 *
345 * The primary function for committing a transaction to the log. This
346 * function is called by the journal thread to begin a complete commit.
347 */
348void jbd2_journal_commit_transaction(journal_t *journal)
349{
350 struct transaction_stats_s stats;
351 transaction_t *commit_transaction;
352 struct journal_head *jh;
353 struct buffer_head *descriptor;
354 struct buffer_head **wbuf = journal->j_wbuf;
355 int bufs;
356 int escape;
357 int err;
358 unsigned long long blocknr;
359 ktime_t start_time;
360 u64 commit_time;
361 char *tagp = NULL;
362 journal_block_tag_t *tag = NULL;
363 int space_left = 0;
364 int first_tag = 0;
365 int tag_flag;
366 int i;
367 int tag_bytes = journal_tag_bytes(journal);
368 struct buffer_head *cbh = NULL; /* For transactional checksums */
369 __u32 crc32_sum = ~0;
370 struct blk_plug plug;
371 /* Tail of the journal */
372 unsigned long first_block;
373 tid_t first_tid;
374 int update_tail;
375 int csum_size = 0;
376 LIST_HEAD(io_bufs);
377 LIST_HEAD(log_bufs);
378
379 if (jbd2_journal_has_csum_v2or3(journal))
380 csum_size = sizeof(struct jbd2_journal_block_tail);
381
382 /*
383 * First job: lock down the current transaction and wait for
384 * all outstanding updates to complete.
385 */
386
387 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
388 if (journal->j_flags & JBD2_FLUSHED) {
389 jbd2_debug(3, "super block updated\n");
390 mutex_lock_io(&journal->j_checkpoint_mutex);
391 /*
392 * We hold j_checkpoint_mutex so tail cannot change under us.
393 * We don't need any special data guarantees for writing sb
394 * since journal is empty and it is ok for write to be
395 * flushed only with transaction commit.
396 */
397 jbd2_journal_update_sb_log_tail(journal,
398 journal->j_tail_sequence,
399 journal->j_tail, 0);
400 mutex_unlock(&journal->j_checkpoint_mutex);
401 } else {
402 jbd2_debug(3, "superblock not updated\n");
403 }
404
405 J_ASSERT(journal->j_running_transaction != NULL);
406 J_ASSERT(journal->j_committing_transaction == NULL);
407
408 write_lock(&journal->j_state_lock);
409 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
410 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
411 DEFINE_WAIT(wait);
412
413 prepare_to_wait(&journal->j_fc_wait, &wait,
414 TASK_UNINTERRUPTIBLE);
415 write_unlock(&journal->j_state_lock);
416 schedule();
417 write_lock(&journal->j_state_lock);
418 finish_wait(&journal->j_fc_wait, &wait);
419 /*
420 * TODO: by blocking fast commits here, we are increasing
421 * fsync() latency slightly. Strictly speaking, we don't need
422 * to block fast commits until the transaction enters T_FLUSH
423 * state. So an optimization is possible where we block new fast
424 * commits here and wait for existing ones to complete
425 * just before we enter T_FLUSH. That way, the existing fast
426 * commits and this full commit can proceed parallely.
427 */
428 }
429 write_unlock(&journal->j_state_lock);
430
431 commit_transaction = journal->j_running_transaction;
432
433 trace_jbd2_start_commit(journal, commit_transaction);
434 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
435 commit_transaction->t_tid);
436
437 write_lock(&journal->j_state_lock);
438 journal->j_fc_off = 0;
439 J_ASSERT(commit_transaction->t_state == T_RUNNING);
440 commit_transaction->t_state = T_LOCKED;
441
442 trace_jbd2_commit_locking(journal, commit_transaction);
443 stats.run.rs_wait = commit_transaction->t_max_wait;
444 stats.run.rs_request_delay = 0;
445 stats.run.rs_locked = jiffies;
446 if (commit_transaction->t_requested)
447 stats.run.rs_request_delay =
448 jbd2_time_diff(commit_transaction->t_requested,
449 stats.run.rs_locked);
450 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
451 stats.run.rs_locked);
452
453 // waits for any t_updates to finish
454 jbd2_journal_wait_updates(journal);
455
456 commit_transaction->t_state = T_SWITCH;
457
458 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
459 journal->j_max_transaction_buffers);
460
461 /*
462 * First thing we are allowed to do is to discard any remaining
463 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
464 * that there are no such buffers: if a large filesystem
465 * operation like a truncate needs to split itself over multiple
466 * transactions, then it may try to do a jbd2_journal_restart() while
467 * there are still BJ_Reserved buffers outstanding. These must
468 * be released cleanly from the current transaction.
469 *
470 * In this case, the filesystem must still reserve write access
471 * again before modifying the buffer in the new transaction, but
472 * we do not require it to remember exactly which old buffers it
473 * has reserved. This is consistent with the existing behaviour
474 * that multiple jbd2_journal_get_write_access() calls to the same
475 * buffer are perfectly permissible.
476 * We use journal->j_state_lock here to serialize processing of
477 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
478 */
479 while (commit_transaction->t_reserved_list) {
480 jh = commit_transaction->t_reserved_list;
481 JBUFFER_TRACE(jh, "reserved, unused: refile");
482 /*
483 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
484 * leave undo-committed data.
485 */
486 if (jh->b_committed_data) {
487 struct buffer_head *bh = jh2bh(jh);
488
489 spin_lock(&jh->b_state_lock);
490 jbd2_free(jh->b_committed_data, bh->b_size);
491 jh->b_committed_data = NULL;
492 spin_unlock(&jh->b_state_lock);
493 }
494 jbd2_journal_refile_buffer(journal, jh);
495 }
496
497 write_unlock(&journal->j_state_lock);
498 /*
499 * Now try to drop any written-back buffers from the journal's
500 * checkpoint lists. We do this *before* commit because it potentially
501 * frees some memory
502 */
503 spin_lock(&journal->j_list_lock);
504 __jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_BUSY_STOP);
505 spin_unlock(&journal->j_list_lock);
506
507 jbd2_debug(3, "JBD2: commit phase 1\n");
508
509 /*
510 * Clear revoked flag to reflect there is no revoked buffers
511 * in the next transaction which is going to be started.
512 */
513 jbd2_clear_buffer_revoked_flags(journal);
514
515 /*
516 * Switch to a new revoke table.
517 */
518 jbd2_journal_switch_revoke_table(journal);
519
520 write_lock(&journal->j_state_lock);
521 /*
522 * Reserved credits cannot be claimed anymore, free them
523 */
524 atomic_sub(atomic_read(&journal->j_reserved_credits),
525 &commit_transaction->t_outstanding_credits);
526
527 trace_jbd2_commit_flushing(journal, commit_transaction);
528 stats.run.rs_flushing = jiffies;
529 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
530 stats.run.rs_flushing);
531
532 commit_transaction->t_state = T_FLUSH;
533 journal->j_committing_transaction = commit_transaction;
534 journal->j_running_transaction = NULL;
535 start_time = ktime_get();
536 commit_transaction->t_log_start = journal->j_head;
537 wake_up_all(&journal->j_wait_transaction_locked);
538 write_unlock(&journal->j_state_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 2a\n");
541
542 /*
543 * Now start flushing things to disk, in the order they appear
544 * on the transaction lists. Data blocks go first.
545 */
546 err = journal_submit_data_buffers(journal, commit_transaction);
547 if (err)
548 jbd2_journal_abort(journal, err);
549
550 blk_start_plug(&plug);
551 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
552
553 jbd2_debug(3, "JBD2: commit phase 2b\n");
554
555 /*
556 * Way to go: we have now written out all of the data for a
557 * transaction! Now comes the tricky part: we need to write out
558 * metadata. Loop over the transaction's entire buffer list:
559 */
560 write_lock(&journal->j_state_lock);
561 commit_transaction->t_state = T_COMMIT;
562 write_unlock(&journal->j_state_lock);
563
564 trace_jbd2_commit_logging(journal, commit_transaction);
565 stats.run.rs_logging = jiffies;
566 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
567 stats.run.rs_logging);
568 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
569 stats.run.rs_blocks_logged = 0;
570
571 J_ASSERT(commit_transaction->t_nr_buffers <=
572 atomic_read(&commit_transaction->t_outstanding_credits));
573
574 bufs = 0;
575 descriptor = NULL;
576 while (commit_transaction->t_buffers) {
577
578 /* Find the next buffer to be journaled... */
579
580 jh = commit_transaction->t_buffers;
581
582 /* If we're in abort mode, we just un-journal the buffer and
583 release it. */
584
585 if (is_journal_aborted(journal)) {
586 clear_buffer_jbddirty(jh2bh(jh));
587 JBUFFER_TRACE(jh, "journal is aborting: refile");
588 jbd2_buffer_abort_trigger(jh,
589 jh->b_frozen_data ?
590 jh->b_frozen_triggers :
591 jh->b_triggers);
592 jbd2_journal_refile_buffer(journal, jh);
593 /* If that was the last one, we need to clean up
594 * any descriptor buffers which may have been
595 * already allocated, even if we are now
596 * aborting. */
597 if (!commit_transaction->t_buffers)
598 goto start_journal_io;
599 continue;
600 }
601
602 /* Make sure we have a descriptor block in which to
603 record the metadata buffer. */
604
605 if (!descriptor) {
606 J_ASSERT (bufs == 0);
607
608 jbd2_debug(4, "JBD2: get descriptor\n");
609
610 descriptor = jbd2_journal_get_descriptor_buffer(
611 commit_transaction,
612 JBD2_DESCRIPTOR_BLOCK);
613 if (!descriptor) {
614 jbd2_journal_abort(journal, -EIO);
615 continue;
616 }
617
618 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
619 (unsigned long long)descriptor->b_blocknr,
620 descriptor->b_data);
621 tagp = &descriptor->b_data[sizeof(journal_header_t)];
622 space_left = descriptor->b_size -
623 sizeof(journal_header_t);
624 first_tag = 1;
625 set_buffer_jwrite(descriptor);
626 set_buffer_dirty(descriptor);
627 wbuf[bufs++] = descriptor;
628
629 /* Record it so that we can wait for IO
630 completion later */
631 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
632 jbd2_file_log_bh(&log_bufs, descriptor);
633 }
634
635 /* Where is the buffer to be written? */
636
637 err = jbd2_journal_next_log_block(journal, &blocknr);
638 /* If the block mapping failed, just abandon the buffer
639 and repeat this loop: we'll fall into the
640 refile-on-abort condition above. */
641 if (err) {
642 jbd2_journal_abort(journal, err);
643 continue;
644 }
645
646 /*
647 * start_this_handle() uses t_outstanding_credits to determine
648 * the free space in the log.
649 */
650 atomic_dec(&commit_transaction->t_outstanding_credits);
651
652 /* Bump b_count to prevent truncate from stumbling over
653 the shadowed buffer! @@@ This can go if we ever get
654 rid of the shadow pairing of buffers. */
655 atomic_inc(&jh2bh(jh)->b_count);
656
657 /*
658 * Make a temporary IO buffer with which to write it out
659 * (this will requeue the metadata buffer to BJ_Shadow).
660 */
661 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
662 JBUFFER_TRACE(jh, "ph3: write metadata");
663 escape = jbd2_journal_write_metadata_buffer(commit_transaction,
664 jh, &wbuf[bufs], blocknr);
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 (escape)
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 jbd2_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 /*
715 * Compute checksum.
716 */
717 if (jbd2_has_feature_checksum(journal)) {
718 crc32_sum =
719 jbd2_checksum_data(crc32_sum, bh);
720 }
721
722 lock_buffer(bh);
723 clear_buffer_dirty(bh);
724 set_buffer_uptodate(bh);
725 bh->b_end_io = journal_end_buffer_io_sync;
726 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
727 bh);
728 }
729 cond_resched();
730
731 /* Force a new descriptor to be generated next
732 time round the loop. */
733 descriptor = NULL;
734 bufs = 0;
735 }
736 }
737
738 err = journal_finish_inode_data_buffers(journal, commit_transaction);
739 if (err) {
740 printk(KERN_WARNING
741 "JBD2: Detected IO errors while flushing file data "
742 "on %s\n", journal->j_devname);
743 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
744 jbd2_journal_abort(journal, err);
745 err = 0;
746 }
747
748 /*
749 * Get current oldest transaction in the log before we issue flush
750 * to the filesystem device. After the flush we can be sure that
751 * blocks of all older transactions are checkpointed to persistent
752 * storage and we will be safe to update journal start in the
753 * superblock with the numbers we get here.
754 */
755 update_tail =
756 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
757
758 write_lock(&journal->j_state_lock);
759 if (update_tail) {
760 long freed = first_block - journal->j_tail;
761
762 if (first_block < journal->j_tail)
763 freed += journal->j_last - journal->j_first;
764 /* Update tail only if we free significant amount of space */
765 if (freed < journal->j_max_transaction_buffers)
766 update_tail = 0;
767 }
768 J_ASSERT(commit_transaction->t_state == T_COMMIT);
769 commit_transaction->t_state = T_COMMIT_DFLUSH;
770 write_unlock(&journal->j_state_lock);
771
772 /*
773 * If the journal is not located on the file system device,
774 * then we must flush the file system device before we issue
775 * the commit record and update the journal tail sequence.
776 */
777 if ((commit_transaction->t_need_data_flush || update_tail) &&
778 (journal->j_fs_dev != journal->j_dev) &&
779 (journal->j_flags & JBD2_BARRIER))
780 blkdev_issue_flush(journal->j_fs_dev);
781
782 /* Done it all: now write the commit record asynchronously. */
783 if (jbd2_has_feature_async_commit(journal)) {
784 err = journal_submit_commit_record(journal, commit_transaction,
785 &cbh, crc32_sum);
786 if (err)
787 jbd2_journal_abort(journal, err);
788 }
789
790 blk_finish_plug(&plug);
791
792 /* Lo and behold: we have just managed to send a transaction to
793 the log. Before we can commit it, wait for the IO so far to
794 complete. Control buffers being written are on the
795 transaction's t_log_list queue, and metadata buffers are on
796 the io_bufs list.
797
798 Wait for the buffers in reverse order. That way we are
799 less likely to be woken up until all IOs have completed, and
800 so we incur less scheduling load.
801 */
802
803 jbd2_debug(3, "JBD2: commit phase 3\n");
804
805 while (!list_empty(&io_bufs)) {
806 struct buffer_head *bh = list_entry(io_bufs.prev,
807 struct buffer_head,
808 b_assoc_buffers);
809
810 wait_on_buffer(bh);
811 cond_resched();
812
813 if (unlikely(!buffer_uptodate(bh)))
814 err = -EIO;
815 jbd2_unfile_log_bh(bh);
816 stats.run.rs_blocks_logged++;
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 jbd2_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 stats.run.rs_blocks_logged++;
863 __brelse(bh); /* One for getblk */
864 /* AKPM: bforget here */
865 }
866
867 if (err)
868 jbd2_journal_abort(journal, err);
869
870 jbd2_debug(3, "JBD2: commit phase 5\n");
871 write_lock(&journal->j_state_lock);
872 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
873 commit_transaction->t_state = T_COMMIT_JFLUSH;
874 write_unlock(&journal->j_state_lock);
875
876 if (!jbd2_has_feature_async_commit(journal)) {
877 err = journal_submit_commit_record(journal, commit_transaction,
878 &cbh, crc32_sum);
879 if (err)
880 jbd2_journal_abort(journal, err);
881 }
882 if (cbh)
883 err = journal_wait_on_commit_record(journal, cbh);
884 stats.run.rs_blocks_logged++;
885 if (jbd2_has_feature_async_commit(journal) &&
886 journal->j_flags & JBD2_BARRIER) {
887 blkdev_issue_flush(journal->j_dev);
888 }
889
890 if (err)
891 jbd2_journal_abort(journal, err);
892
893 WARN_ON_ONCE(
894 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
895
896 /*
897 * Now disk caches for filesystem device are flushed so we are safe to
898 * erase checkpointed transactions from the log by updating journal
899 * superblock.
900 */
901 if (update_tail)
902 jbd2_update_log_tail(journal, first_tid, first_block);
903
904 /* End of a transaction! Finally, we can do checkpoint
905 processing: any buffers committed as a result of this
906 transaction can be removed from any checkpoint list it was on
907 before. */
908
909 jbd2_debug(3, "JBD2: commit phase 6\n");
910
911 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
912 J_ASSERT(commit_transaction->t_buffers == NULL);
913 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
914 J_ASSERT(commit_transaction->t_shadow_list == NULL);
915
916restart_loop:
917 /*
918 * As there are other places (journal_unmap_buffer()) adding buffers
919 * to this list we have to be careful and hold the j_list_lock.
920 */
921 spin_lock(&journal->j_list_lock);
922 while (commit_transaction->t_forget) {
923 transaction_t *cp_transaction;
924 struct buffer_head *bh;
925 int try_to_free = 0;
926 bool drop_ref;
927
928 jh = commit_transaction->t_forget;
929 spin_unlock(&journal->j_list_lock);
930 bh = jh2bh(jh);
931 /*
932 * Get a reference so that bh cannot be freed before we are
933 * done with it.
934 */
935 get_bh(bh);
936 spin_lock(&jh->b_state_lock);
937 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
938
939 /*
940 * If there is undo-protected committed data against
941 * this buffer, then we can remove it now. If it is a
942 * buffer needing such protection, the old frozen_data
943 * field now points to a committed version of the
944 * buffer, so rotate that field to the new committed
945 * data.
946 *
947 * Otherwise, we can just throw away the frozen data now.
948 *
949 * We also know that the frozen data has already fired
950 * its triggers if they exist, so we can clear that too.
951 */
952 if (jh->b_committed_data) {
953 jbd2_free(jh->b_committed_data, bh->b_size);
954 jh->b_committed_data = NULL;
955 if (jh->b_frozen_data) {
956 jh->b_committed_data = jh->b_frozen_data;
957 jh->b_frozen_data = NULL;
958 jh->b_frozen_triggers = NULL;
959 }
960 } else if (jh->b_frozen_data) {
961 jbd2_free(jh->b_frozen_data, bh->b_size);
962 jh->b_frozen_data = NULL;
963 jh->b_frozen_triggers = NULL;
964 }
965
966 spin_lock(&journal->j_list_lock);
967 cp_transaction = jh->b_cp_transaction;
968 if (cp_transaction) {
969 JBUFFER_TRACE(jh, "remove from old cp transaction");
970 cp_transaction->t_chp_stats.cs_dropped++;
971 __jbd2_journal_remove_checkpoint(jh);
972 }
973
974 /* Only re-checkpoint the buffer_head if it is marked
975 * dirty. If the buffer was added to the BJ_Forget list
976 * by jbd2_journal_forget, it may no longer be dirty and
977 * there's no point in keeping a checkpoint record for
978 * it. */
979
980 /*
981 * A buffer which has been freed while still being journaled
982 * by a previous transaction, refile the buffer to BJ_Forget of
983 * the running transaction. If the just committed transaction
984 * contains "add to orphan" operation, we can completely
985 * invalidate the buffer now. We are rather through in that
986 * since the buffer may be still accessible when blocksize <
987 * pagesize and it is attached to the last partial page.
988 */
989 if (buffer_freed(bh) && !jh->b_next_transaction) {
990 struct address_space *mapping;
991
992 clear_buffer_freed(bh);
993 clear_buffer_jbddirty(bh);
994
995 /*
996 * Block device buffers need to stay mapped all the
997 * time, so it is enough to clear buffer_jbddirty and
998 * buffer_freed bits. For the file mapping buffers (i.e.
999 * journalled data) we need to unmap buffer and clear
1000 * more bits. We also need to be careful about the check
1001 * because the data page mapping can get cleared under
1002 * our hands. Note that if mapping == NULL, we don't
1003 * need to make buffer unmapped because the page is
1004 * already detached from the mapping and buffers cannot
1005 * get reused.
1006 */
1007 mapping = READ_ONCE(bh->b_folio->mapping);
1008 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1009 clear_buffer_mapped(bh);
1010 clear_buffer_new(bh);
1011 clear_buffer_req(bh);
1012 bh->b_bdev = NULL;
1013 }
1014 }
1015
1016 if (buffer_jbddirty(bh)) {
1017 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1018 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1019 if (is_journal_aborted(journal))
1020 clear_buffer_jbddirty(bh);
1021 } else {
1022 J_ASSERT_BH(bh, !buffer_dirty(bh));
1023 /*
1024 * The buffer on BJ_Forget list and not jbddirty means
1025 * it has been freed by this transaction and hence it
1026 * could not have been reallocated until this
1027 * transaction has committed. *BUT* it could be
1028 * reallocated once we have written all the data to
1029 * disk and before we process the buffer on BJ_Forget
1030 * list.
1031 */
1032 if (!jh->b_next_transaction)
1033 try_to_free = 1;
1034 }
1035 JBUFFER_TRACE(jh, "refile or unfile buffer");
1036 drop_ref = __jbd2_journal_refile_buffer(jh);
1037 spin_unlock(&jh->b_state_lock);
1038 if (drop_ref)
1039 jbd2_journal_put_journal_head(jh);
1040 if (try_to_free)
1041 release_buffer_page(bh); /* Drops bh reference */
1042 else
1043 __brelse(bh);
1044 cond_resched_lock(&journal->j_list_lock);
1045 }
1046 spin_unlock(&journal->j_list_lock);
1047 /*
1048 * This is a bit sleazy. We use j_list_lock to protect transition
1049 * of a transaction into T_FINISHED state and calling
1050 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1051 * other checkpointing code processing the transaction...
1052 */
1053 write_lock(&journal->j_state_lock);
1054 spin_lock(&journal->j_list_lock);
1055 /*
1056 * Now recheck if some buffers did not get attached to the transaction
1057 * while the lock was dropped...
1058 */
1059 if (commit_transaction->t_forget) {
1060 spin_unlock(&journal->j_list_lock);
1061 write_unlock(&journal->j_state_lock);
1062 goto restart_loop;
1063 }
1064
1065 /* Add the transaction to the checkpoint list
1066 * __journal_remove_checkpoint() can not destroy transaction
1067 * under us because it is not marked as T_FINISHED yet */
1068 if (journal->j_checkpoint_transactions == NULL) {
1069 journal->j_checkpoint_transactions = commit_transaction;
1070 commit_transaction->t_cpnext = commit_transaction;
1071 commit_transaction->t_cpprev = commit_transaction;
1072 } else {
1073 commit_transaction->t_cpnext =
1074 journal->j_checkpoint_transactions;
1075 commit_transaction->t_cpprev =
1076 commit_transaction->t_cpnext->t_cpprev;
1077 commit_transaction->t_cpnext->t_cpprev =
1078 commit_transaction;
1079 commit_transaction->t_cpprev->t_cpnext =
1080 commit_transaction;
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083
1084 /* Done with this transaction! */
1085
1086 jbd2_debug(3, "JBD2: commit phase 7\n");
1087
1088 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1089
1090 commit_transaction->t_start = jiffies;
1091 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1092 commit_transaction->t_start);
1093
1094 /*
1095 * File the transaction statistics
1096 */
1097 stats.ts_tid = commit_transaction->t_tid;
1098 stats.run.rs_handle_count =
1099 atomic_read(&commit_transaction->t_handle_count);
1100 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1101 commit_transaction->t_tid, &stats.run);
1102 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1103
1104 commit_transaction->t_state = T_COMMIT_CALLBACK;
1105 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1106 WRITE_ONCE(journal->j_commit_sequence, commit_transaction->t_tid);
1107 journal->j_committing_transaction = NULL;
1108 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1109
1110 /*
1111 * weight the commit time higher than the average time so we don't
1112 * react too strongly to vast changes in the commit time
1113 */
1114 if (likely(journal->j_average_commit_time))
1115 journal->j_average_commit_time = (commit_time +
1116 journal->j_average_commit_time*3) / 4;
1117 else
1118 journal->j_average_commit_time = commit_time;
1119
1120 write_unlock(&journal->j_state_lock);
1121
1122 if (journal->j_commit_callback)
1123 journal->j_commit_callback(journal, commit_transaction);
1124 if (journal->j_fc_cleanup_callback)
1125 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1126
1127 trace_jbd2_end_commit(journal, commit_transaction);
1128 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1129 journal->j_commit_sequence, journal->j_tail_sequence);
1130
1131 write_lock(&journal->j_state_lock);
1132 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1133 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1134 spin_lock(&journal->j_list_lock);
1135 commit_transaction->t_state = T_FINISHED;
1136 /* Check if the transaction can be dropped now that we are finished */
1137 if (commit_transaction->t_checkpoint_list == NULL) {
1138 __jbd2_journal_drop_transaction(journal, commit_transaction);
1139 jbd2_journal_free_transaction(commit_transaction);
1140 }
1141 spin_unlock(&journal->j_list_lock);
1142 write_unlock(&journal->j_state_lock);
1143 wake_up(&journal->j_wait_done_commit);
1144 wake_up(&journal->j_fc_wait);
1145
1146 /*
1147 * Calculate overall stats
1148 */
1149 spin_lock(&journal->j_history_lock);
1150 journal->j_stats.ts_tid++;
1151 journal->j_stats.ts_requested += stats.ts_requested;
1152 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1153 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1154 journal->j_stats.run.rs_running += stats.run.rs_running;
1155 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1156 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1157 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1158 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1159 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1160 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1161 spin_unlock(&journal->j_history_lock);
1162}