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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 folio *folio;
66 struct page *page;
67
68 if (buffer_dirty(bh))
69 goto nope;
70 if (atomic_read(&bh->b_count) != 1)
71 goto nope;
72 page = bh->b_page;
73 if (!page)
74 goto nope;
75 folio = page_folio(page);
76 if (folio->mapping)
77 goto nope;
78
79 /* OK, it's a truncated page */
80 if (!folio_trylock(folio))
81 goto nope;
82
83 folio_get(folio);
84 __brelse(bh);
85 try_to_free_buffers(folio);
86 folio_unlock(folio);
87 folio_put(folio);
88 return;
89
90nope:
91 __brelse(bh);
92}
93
94static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
95{
96 struct commit_header *h;
97 __u32 csum;
98
99 if (!jbd2_journal_has_csum_v2or3(j))
100 return;
101
102 h = (struct commit_header *)(bh->b_data);
103 h->h_chksum_type = 0;
104 h->h_chksum_size = 0;
105 h->h_chksum[0] = 0;
106 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
107 h->h_chksum[0] = cpu_to_be32(csum);
108}
109
110/*
111 * Done it all: now submit the commit record. We should have
112 * cleaned up our previous buffers by now, so if we are in abort
113 * mode we can now just skip the rest of the journal write
114 * entirely.
115 *
116 * Returns 1 if the journal needs to be aborted or 0 on success
117 */
118static int journal_submit_commit_record(journal_t *journal,
119 transaction_t *commit_transaction,
120 struct buffer_head **cbh,
121 __u32 crc32_sum)
122{
123 struct commit_header *tmp;
124 struct buffer_head *bh;
125 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | REQ_SYNC;
127
128 *cbh = NULL;
129
130 if (is_journal_aborted(journal))
131 return 0;
132
133 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
134 JBD2_COMMIT_BLOCK);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 ktime_get_coarse_real_ts64(&now);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 write_flags |= REQ_PREFLUSH | REQ_FUA;
159
160 submit_bh(write_flags, bh);
161 *cbh = bh;
162 return 0;
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 */
190int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
191{
192 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
193 struct writeback_control wbc = {
194 .sync_mode = WB_SYNC_ALL,
195 .nr_to_write = mapping->nrpages * 2,
196 .range_start = jinode->i_dirty_start,
197 .range_end = jinode->i_dirty_end,
198 };
199
200 /*
201 * submit the inode data buffers. We use writepage
202 * instead of writepages. Because writepages can do
203 * block allocation with delalloc. We need to write
204 * only allocated blocks here.
205 */
206 return generic_writepages(mapping, &wbc);
207}
208
209/* Send all the data buffers related to an inode */
210int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
211{
212 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
213 return 0;
214
215 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
216 return journal->j_submit_inode_data_buffers(jinode);
217
218}
219EXPORT_SYMBOL(jbd2_submit_inode_data);
220
221int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
222{
223 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
224 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
225 return 0;
226 return filemap_fdatawait_range_keep_errors(
227 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
228 jinode->i_dirty_end);
229}
230EXPORT_SYMBOL(jbd2_wait_inode_data);
231
232/*
233 * Submit all the data buffers of inode associated with the transaction to
234 * disk.
235 *
236 * We are in a committing transaction. Therefore no new inode can be added to
237 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
238 * operate on from being released while we write out pages.
239 */
240static int journal_submit_data_buffers(journal_t *journal,
241 transaction_t *commit_transaction)
242{
243 struct jbd2_inode *jinode;
244 int err, ret = 0;
245
246 spin_lock(&journal->j_list_lock);
247 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
248 if (!(jinode->i_flags & JI_WRITE_DATA))
249 continue;
250 jinode->i_flags |= JI_COMMIT_RUNNING;
251 spin_unlock(&journal->j_list_lock);
252 /* submit the inode data buffers. */
253 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
254 if (journal->j_submit_inode_data_buffers) {
255 err = journal->j_submit_inode_data_buffers(jinode);
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 J_ASSERT(jinode->i_transaction == commit_transaction);
261 jinode->i_flags &= ~JI_COMMIT_RUNNING;
262 smp_mb();
263 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
264 }
265 spin_unlock(&journal->j_list_lock);
266 return ret;
267}
268
269int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
270{
271 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
272
273 return filemap_fdatawait_range_keep_errors(mapping,
274 jinode->i_dirty_start,
275 jinode->i_dirty_end);
276}
277
278/*
279 * Wait for data submitted for writeout, refile inodes to proper
280 * transaction if needed.
281 *
282 */
283static int journal_finish_inode_data_buffers(journal_t *journal,
284 transaction_t *commit_transaction)
285{
286 struct jbd2_inode *jinode, *next_i;
287 int err, ret = 0;
288
289 /* For locking, see the comment in journal_submit_data_buffers() */
290 spin_lock(&journal->j_list_lock);
291 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
292 if (!(jinode->i_flags & JI_WAIT_DATA))
293 continue;
294 jinode->i_flags |= JI_COMMIT_RUNNING;
295 spin_unlock(&journal->j_list_lock);
296 /* wait for the inode data buffers writeout. */
297 if (journal->j_finish_inode_data_buffers) {
298 err = journal->j_finish_inode_data_buffers(jinode);
299 if (!ret)
300 ret = err;
301 }
302 spin_lock(&journal->j_list_lock);
303 jinode->i_flags &= ~JI_COMMIT_RUNNING;
304 smp_mb();
305 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
306 }
307
308 /* Now refile inode to proper lists */
309 list_for_each_entry_safe(jinode, next_i,
310 &commit_transaction->t_inode_list, i_list) {
311 list_del(&jinode->i_list);
312 if (jinode->i_next_transaction) {
313 jinode->i_transaction = jinode->i_next_transaction;
314 jinode->i_next_transaction = NULL;
315 list_add(&jinode->i_list,
316 &jinode->i_transaction->t_inode_list);
317 } else {
318 jinode->i_transaction = NULL;
319 jinode->i_dirty_start = 0;
320 jinode->i_dirty_end = 0;
321 }
322 }
323 spin_unlock(&journal->j_list_lock);
324
325 return ret;
326}
327
328static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
329{
330 struct page *page = bh->b_page;
331 char *addr;
332 __u32 checksum;
333
334 addr = kmap_atomic(page);
335 checksum = crc32_be(crc32_sum,
336 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
337 kunmap_atomic(addr);
338
339 return checksum;
340}
341
342static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
343 unsigned long long block)
344{
345 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
346 if (jbd2_has_feature_64bit(j))
347 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
348}
349
350static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
351 struct buffer_head *bh, __u32 sequence)
352{
353 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
354 struct page *page = bh->b_page;
355 __u8 *addr;
356 __u32 csum32;
357 __be32 seq;
358
359 if (!jbd2_journal_has_csum_v2or3(j))
360 return;
361
362 seq = cpu_to_be32(sequence);
363 addr = kmap_atomic(page);
364 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
365 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
366 bh->b_size);
367 kunmap_atomic(addr);
368
369 if (jbd2_has_feature_csum3(j))
370 tag3->t_checksum = cpu_to_be32(csum32);
371 else
372 tag->t_checksum = cpu_to_be16(csum32);
373}
374/*
375 * jbd2_journal_commit_transaction
376 *
377 * The primary function for committing a transaction to the log. This
378 * function is called by the journal thread to begin a complete commit.
379 */
380void jbd2_journal_commit_transaction(journal_t *journal)
381{
382 struct transaction_stats_s stats;
383 transaction_t *commit_transaction;
384 struct journal_head *jh;
385 struct buffer_head *descriptor;
386 struct buffer_head **wbuf = journal->j_wbuf;
387 int bufs;
388 int flags;
389 int err;
390 unsigned long long blocknr;
391 ktime_t start_time;
392 u64 commit_time;
393 char *tagp = NULL;
394 journal_block_tag_t *tag = NULL;
395 int space_left = 0;
396 int first_tag = 0;
397 int tag_flag;
398 int i;
399 int tag_bytes = journal_tag_bytes(journal);
400 struct buffer_head *cbh = NULL; /* For transactional checksums */
401 __u32 crc32_sum = ~0;
402 struct blk_plug plug;
403 /* Tail of the journal */
404 unsigned long first_block;
405 tid_t first_tid;
406 int update_tail;
407 int csum_size = 0;
408 LIST_HEAD(io_bufs);
409 LIST_HEAD(log_bufs);
410
411 if (jbd2_journal_has_csum_v2or3(journal))
412 csum_size = sizeof(struct jbd2_journal_block_tail);
413
414 /*
415 * First job: lock down the current transaction and wait for
416 * all outstanding updates to complete.
417 */
418
419 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
420 if (journal->j_flags & JBD2_FLUSHED) {
421 jbd2_debug(3, "super block updated\n");
422 mutex_lock_io(&journal->j_checkpoint_mutex);
423 /*
424 * We hold j_checkpoint_mutex so tail cannot change under us.
425 * We don't need any special data guarantees for writing sb
426 * since journal is empty and it is ok for write to be
427 * flushed only with transaction commit.
428 */
429 jbd2_journal_update_sb_log_tail(journal,
430 journal->j_tail_sequence,
431 journal->j_tail,
432 REQ_SYNC);
433 mutex_unlock(&journal->j_checkpoint_mutex);
434 } else {
435 jbd2_debug(3, "superblock not updated\n");
436 }
437
438 J_ASSERT(journal->j_running_transaction != NULL);
439 J_ASSERT(journal->j_committing_transaction == NULL);
440
441 write_lock(&journal->j_state_lock);
442 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
443 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_fc_wait, &wait,
447 TASK_UNINTERRUPTIBLE);
448 write_unlock(&journal->j_state_lock);
449 schedule();
450 write_lock(&journal->j_state_lock);
451 finish_wait(&journal->j_fc_wait, &wait);
452 /*
453 * TODO: by blocking fast commits here, we are increasing
454 * fsync() latency slightly. Strictly speaking, we don't need
455 * to block fast commits until the transaction enters T_FLUSH
456 * state. So an optimization is possible where we block new fast
457 * commits here and wait for existing ones to complete
458 * just before we enter T_FLUSH. That way, the existing fast
459 * commits and this full commit can proceed parallely.
460 */
461 }
462 write_unlock(&journal->j_state_lock);
463
464 commit_transaction = journal->j_running_transaction;
465
466 trace_jbd2_start_commit(journal, commit_transaction);
467 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
468 commit_transaction->t_tid);
469
470 write_lock(&journal->j_state_lock);
471 journal->j_fc_off = 0;
472 J_ASSERT(commit_transaction->t_state == T_RUNNING);
473 commit_transaction->t_state = T_LOCKED;
474
475 trace_jbd2_commit_locking(journal, commit_transaction);
476 stats.run.rs_wait = commit_transaction->t_max_wait;
477 stats.run.rs_request_delay = 0;
478 stats.run.rs_locked = jiffies;
479 if (commit_transaction->t_requested)
480 stats.run.rs_request_delay =
481 jbd2_time_diff(commit_transaction->t_requested,
482 stats.run.rs_locked);
483 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
484 stats.run.rs_locked);
485
486 // waits for any t_updates to finish
487 jbd2_journal_wait_updates(journal);
488
489 commit_transaction->t_state = T_SWITCH;
490
491 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
492 journal->j_max_transaction_buffers);
493
494 /*
495 * First thing we are allowed to do is to discard any remaining
496 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
497 * that there are no such buffers: if a large filesystem
498 * operation like a truncate needs to split itself over multiple
499 * transactions, then it may try to do a jbd2_journal_restart() while
500 * there are still BJ_Reserved buffers outstanding. These must
501 * be released cleanly from the current transaction.
502 *
503 * In this case, the filesystem must still reserve write access
504 * again before modifying the buffer in the new transaction, but
505 * we do not require it to remember exactly which old buffers it
506 * has reserved. This is consistent with the existing behaviour
507 * that multiple jbd2_journal_get_write_access() calls to the same
508 * buffer are perfectly permissible.
509 * We use journal->j_state_lock here to serialize processing of
510 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
511 */
512 while (commit_transaction->t_reserved_list) {
513 jh = commit_transaction->t_reserved_list;
514 JBUFFER_TRACE(jh, "reserved, unused: refile");
515 /*
516 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
517 * leave undo-committed data.
518 */
519 if (jh->b_committed_data) {
520 struct buffer_head *bh = jh2bh(jh);
521
522 spin_lock(&jh->b_state_lock);
523 jbd2_free(jh->b_committed_data, bh->b_size);
524 jh->b_committed_data = NULL;
525 spin_unlock(&jh->b_state_lock);
526 }
527 jbd2_journal_refile_buffer(journal, jh);
528 }
529
530 write_unlock(&journal->j_state_lock);
531 /*
532 * Now try to drop any written-back buffers from the journal's
533 * checkpoint lists. We do this *before* commit because it potentially
534 * frees some memory
535 */
536 spin_lock(&journal->j_list_lock);
537 __jbd2_journal_clean_checkpoint_list(journal, false);
538 spin_unlock(&journal->j_list_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 1\n");
541
542 /*
543 * Clear revoked flag to reflect there is no revoked buffers
544 * in the next transaction which is going to be started.
545 */
546 jbd2_clear_buffer_revoked_flags(journal);
547
548 /*
549 * Switch to a new revoke table.
550 */
551 jbd2_journal_switch_revoke_table(journal);
552
553 write_lock(&journal->j_state_lock);
554 /*
555 * Reserved credits cannot be claimed anymore, free them
556 */
557 atomic_sub(atomic_read(&journal->j_reserved_credits),
558 &commit_transaction->t_outstanding_credits);
559
560 trace_jbd2_commit_flushing(journal, commit_transaction);
561 stats.run.rs_flushing = jiffies;
562 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
563 stats.run.rs_flushing);
564
565 commit_transaction->t_state = T_FLUSH;
566 journal->j_committing_transaction = commit_transaction;
567 journal->j_running_transaction = NULL;
568 start_time = ktime_get();
569 commit_transaction->t_log_start = journal->j_head;
570 wake_up_all(&journal->j_wait_transaction_locked);
571 write_unlock(&journal->j_state_lock);
572
573 jbd2_debug(3, "JBD2: commit phase 2a\n");
574
575 /*
576 * Now start flushing things to disk, in the order they appear
577 * on the transaction lists. Data blocks go first.
578 */
579 err = journal_submit_data_buffers(journal, commit_transaction);
580 if (err)
581 jbd2_journal_abort(journal, err);
582
583 blk_start_plug(&plug);
584 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
585
586 jbd2_debug(3, "JBD2: commit phase 2b\n");
587
588 /*
589 * Way to go: we have now written out all of the data for a
590 * transaction! Now comes the tricky part: we need to write out
591 * metadata. Loop over the transaction's entire buffer list:
592 */
593 write_lock(&journal->j_state_lock);
594 commit_transaction->t_state = T_COMMIT;
595 write_unlock(&journal->j_state_lock);
596
597 trace_jbd2_commit_logging(journal, commit_transaction);
598 stats.run.rs_logging = jiffies;
599 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
600 stats.run.rs_logging);
601 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
602 stats.run.rs_blocks_logged = 0;
603
604 J_ASSERT(commit_transaction->t_nr_buffers <=
605 atomic_read(&commit_transaction->t_outstanding_credits));
606
607 err = 0;
608 bufs = 0;
609 descriptor = NULL;
610 while (commit_transaction->t_buffers) {
611
612 /* Find the next buffer to be journaled... */
613
614 jh = commit_transaction->t_buffers;
615
616 /* If we're in abort mode, we just un-journal the buffer and
617 release it. */
618
619 if (is_journal_aborted(journal)) {
620 clear_buffer_jbddirty(jh2bh(jh));
621 JBUFFER_TRACE(jh, "journal is aborting: refile");
622 jbd2_buffer_abort_trigger(jh,
623 jh->b_frozen_data ?
624 jh->b_frozen_triggers :
625 jh->b_triggers);
626 jbd2_journal_refile_buffer(journal, jh);
627 /* If that was the last one, we need to clean up
628 * any descriptor buffers which may have been
629 * already allocated, even if we are now
630 * aborting. */
631 if (!commit_transaction->t_buffers)
632 goto start_journal_io;
633 continue;
634 }
635
636 /* Make sure we have a descriptor block in which to
637 record the metadata buffer. */
638
639 if (!descriptor) {
640 J_ASSERT (bufs == 0);
641
642 jbd2_debug(4, "JBD2: get descriptor\n");
643
644 descriptor = jbd2_journal_get_descriptor_buffer(
645 commit_transaction,
646 JBD2_DESCRIPTOR_BLOCK);
647 if (!descriptor) {
648 jbd2_journal_abort(journal, -EIO);
649 continue;
650 }
651
652 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
653 (unsigned long long)descriptor->b_blocknr,
654 descriptor->b_data);
655 tagp = &descriptor->b_data[sizeof(journal_header_t)];
656 space_left = descriptor->b_size -
657 sizeof(journal_header_t);
658 first_tag = 1;
659 set_buffer_jwrite(descriptor);
660 set_buffer_dirty(descriptor);
661 wbuf[bufs++] = descriptor;
662
663 /* Record it so that we can wait for IO
664 completion later */
665 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
666 jbd2_file_log_bh(&log_bufs, descriptor);
667 }
668
669 /* Where is the buffer to be written? */
670
671 err = jbd2_journal_next_log_block(journal, &blocknr);
672 /* If the block mapping failed, just abandon the buffer
673 and repeat this loop: we'll fall into the
674 refile-on-abort condition above. */
675 if (err) {
676 jbd2_journal_abort(journal, err);
677 continue;
678 }
679
680 /*
681 * start_this_handle() uses t_outstanding_credits to determine
682 * the free space in the log.
683 */
684 atomic_dec(&commit_transaction->t_outstanding_credits);
685
686 /* Bump b_count to prevent truncate from stumbling over
687 the shadowed buffer! @@@ This can go if we ever get
688 rid of the shadow pairing of buffers. */
689 atomic_inc(&jh2bh(jh)->b_count);
690
691 /*
692 * Make a temporary IO buffer with which to write it out
693 * (this will requeue the metadata buffer to BJ_Shadow).
694 */
695 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
696 JBUFFER_TRACE(jh, "ph3: write metadata");
697 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
698 jh, &wbuf[bufs], blocknr);
699 if (flags < 0) {
700 jbd2_journal_abort(journal, flags);
701 continue;
702 }
703 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
704
705 /* Record the new block's tag in the current descriptor
706 buffer */
707
708 tag_flag = 0;
709 if (flags & 1)
710 tag_flag |= JBD2_FLAG_ESCAPE;
711 if (!first_tag)
712 tag_flag |= JBD2_FLAG_SAME_UUID;
713
714 tag = (journal_block_tag_t *) tagp;
715 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
716 tag->t_flags = cpu_to_be16(tag_flag);
717 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
718 commit_transaction->t_tid);
719 tagp += tag_bytes;
720 space_left -= tag_bytes;
721 bufs++;
722
723 if (first_tag) {
724 memcpy (tagp, journal->j_uuid, 16);
725 tagp += 16;
726 space_left -= 16;
727 first_tag = 0;
728 }
729
730 /* If there's no more to do, or if the descriptor is full,
731 let the IO rip! */
732
733 if (bufs == journal->j_wbufsize ||
734 commit_transaction->t_buffers == NULL ||
735 space_left < tag_bytes + 16 + csum_size) {
736
737 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
738
739 /* Write an end-of-descriptor marker before
740 submitting the IOs. "tag" still points to
741 the last tag we set up. */
742
743 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
744start_journal_io:
745 if (descriptor)
746 jbd2_descriptor_block_csum_set(journal,
747 descriptor);
748
749 for (i = 0; i < bufs; i++) {
750 struct buffer_head *bh = wbuf[i];
751 /*
752 * Compute checksum.
753 */
754 if (jbd2_has_feature_checksum(journal)) {
755 crc32_sum =
756 jbd2_checksum_data(crc32_sum, bh);
757 }
758
759 lock_buffer(bh);
760 clear_buffer_dirty(bh);
761 set_buffer_uptodate(bh);
762 bh->b_end_io = journal_end_buffer_io_sync;
763 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
764 }
765 cond_resched();
766
767 /* Force a new descriptor to be generated next
768 time round the loop. */
769 descriptor = NULL;
770 bufs = 0;
771 }
772 }
773
774 err = journal_finish_inode_data_buffers(journal, commit_transaction);
775 if (err) {
776 printk(KERN_WARNING
777 "JBD2: Detected IO errors while flushing file data "
778 "on %s\n", journal->j_devname);
779 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
780 jbd2_journal_abort(journal, err);
781 err = 0;
782 }
783
784 /*
785 * Get current oldest transaction in the log before we issue flush
786 * to the filesystem device. After the flush we can be sure that
787 * blocks of all older transactions are checkpointed to persistent
788 * storage and we will be safe to update journal start in the
789 * superblock with the numbers we get here.
790 */
791 update_tail =
792 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
793
794 write_lock(&journal->j_state_lock);
795 if (update_tail) {
796 long freed = first_block - journal->j_tail;
797
798 if (first_block < journal->j_tail)
799 freed += journal->j_last - journal->j_first;
800 /* Update tail only if we free significant amount of space */
801 if (freed < jbd2_journal_get_max_txn_bufs(journal))
802 update_tail = 0;
803 }
804 J_ASSERT(commit_transaction->t_state == T_COMMIT);
805 commit_transaction->t_state = T_COMMIT_DFLUSH;
806 write_unlock(&journal->j_state_lock);
807
808 /*
809 * If the journal is not located on the file system device,
810 * then we must flush the file system device before we issue
811 * the commit record
812 */
813 if (commit_transaction->t_need_data_flush &&
814 (journal->j_fs_dev != journal->j_dev) &&
815 (journal->j_flags & JBD2_BARRIER))
816 blkdev_issue_flush(journal->j_fs_dev);
817
818 /* Done it all: now write the commit record asynchronously. */
819 if (jbd2_has_feature_async_commit(journal)) {
820 err = journal_submit_commit_record(journal, commit_transaction,
821 &cbh, crc32_sum);
822 if (err)
823 jbd2_journal_abort(journal, err);
824 }
825
826 blk_finish_plug(&plug);
827
828 /* Lo and behold: we have just managed to send a transaction to
829 the log. Before we can commit it, wait for the IO so far to
830 complete. Control buffers being written are on the
831 transaction's t_log_list queue, and metadata buffers are on
832 the io_bufs list.
833
834 Wait for the buffers in reverse order. That way we are
835 less likely to be woken up until all IOs have completed, and
836 so we incur less scheduling load.
837 */
838
839 jbd2_debug(3, "JBD2: commit phase 3\n");
840
841 while (!list_empty(&io_bufs)) {
842 struct buffer_head *bh = list_entry(io_bufs.prev,
843 struct buffer_head,
844 b_assoc_buffers);
845
846 wait_on_buffer(bh);
847 cond_resched();
848
849 if (unlikely(!buffer_uptodate(bh)))
850 err = -EIO;
851 jbd2_unfile_log_bh(bh);
852 stats.run.rs_blocks_logged++;
853
854 /*
855 * The list contains temporary buffer heads created by
856 * jbd2_journal_write_metadata_buffer().
857 */
858 BUFFER_TRACE(bh, "dumping temporary bh");
859 __brelse(bh);
860 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
861 free_buffer_head(bh);
862
863 /* We also have to refile the corresponding shadowed buffer */
864 jh = commit_transaction->t_shadow_list->b_tprev;
865 bh = jh2bh(jh);
866 clear_buffer_jwrite(bh);
867 J_ASSERT_BH(bh, buffer_jbddirty(bh));
868 J_ASSERT_BH(bh, !buffer_shadow(bh));
869
870 /* The metadata is now released for reuse, but we need
871 to remember it against this transaction so that when
872 we finally commit, we can do any checkpointing
873 required. */
874 JBUFFER_TRACE(jh, "file as BJ_Forget");
875 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
876 JBUFFER_TRACE(jh, "brelse shadowed buffer");
877 __brelse(bh);
878 }
879
880 J_ASSERT (commit_transaction->t_shadow_list == NULL);
881
882 jbd2_debug(3, "JBD2: commit phase 4\n");
883
884 /* Here we wait for the revoke record and descriptor record buffers */
885 while (!list_empty(&log_bufs)) {
886 struct buffer_head *bh;
887
888 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
889 wait_on_buffer(bh);
890 cond_resched();
891
892 if (unlikely(!buffer_uptodate(bh)))
893 err = -EIO;
894
895 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
896 clear_buffer_jwrite(bh);
897 jbd2_unfile_log_bh(bh);
898 stats.run.rs_blocks_logged++;
899 __brelse(bh); /* One for getblk */
900 /* AKPM: bforget here */
901 }
902
903 if (err)
904 jbd2_journal_abort(journal, err);
905
906 jbd2_debug(3, "JBD2: commit phase 5\n");
907 write_lock(&journal->j_state_lock);
908 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
909 commit_transaction->t_state = T_COMMIT_JFLUSH;
910 write_unlock(&journal->j_state_lock);
911
912 if (!jbd2_has_feature_async_commit(journal)) {
913 err = journal_submit_commit_record(journal, commit_transaction,
914 &cbh, crc32_sum);
915 if (err)
916 jbd2_journal_abort(journal, err);
917 }
918 if (cbh)
919 err = journal_wait_on_commit_record(journal, cbh);
920 stats.run.rs_blocks_logged++;
921 if (jbd2_has_feature_async_commit(journal) &&
922 journal->j_flags & JBD2_BARRIER) {
923 blkdev_issue_flush(journal->j_dev);
924 }
925
926 if (err)
927 jbd2_journal_abort(journal, err);
928
929 WARN_ON_ONCE(
930 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd2_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_shadow_list == NULL);
951
952restart_loop:
953 /*
954 * As there are other places (journal_unmap_buffer()) adding buffers
955 * to this list we have to be careful and hold the j_list_lock.
956 */
957 spin_lock(&journal->j_list_lock);
958 while (commit_transaction->t_forget) {
959 transaction_t *cp_transaction;
960 struct buffer_head *bh;
961 int try_to_free = 0;
962 bool drop_ref;
963
964 jh = commit_transaction->t_forget;
965 spin_unlock(&journal->j_list_lock);
966 bh = jh2bh(jh);
967 /*
968 * Get a reference so that bh cannot be freed before we are
969 * done with it.
970 */
971 get_bh(bh);
972 spin_lock(&jh->b_state_lock);
973 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
974
975 /*
976 * If there is undo-protected committed data against
977 * this buffer, then we can remove it now. If it is a
978 * buffer needing such protection, the old frozen_data
979 * field now points to a committed version of the
980 * buffer, so rotate that field to the new committed
981 * data.
982 *
983 * Otherwise, we can just throw away the frozen data now.
984 *
985 * We also know that the frozen data has already fired
986 * its triggers if they exist, so we can clear that too.
987 */
988 if (jh->b_committed_data) {
989 jbd2_free(jh->b_committed_data, bh->b_size);
990 jh->b_committed_data = NULL;
991 if (jh->b_frozen_data) {
992 jh->b_committed_data = jh->b_frozen_data;
993 jh->b_frozen_data = NULL;
994 jh->b_frozen_triggers = NULL;
995 }
996 } else if (jh->b_frozen_data) {
997 jbd2_free(jh->b_frozen_data, bh->b_size);
998 jh->b_frozen_data = NULL;
999 jh->b_frozen_triggers = NULL;
1000 }
1001
1002 spin_lock(&journal->j_list_lock);
1003 cp_transaction = jh->b_cp_transaction;
1004 if (cp_transaction) {
1005 JBUFFER_TRACE(jh, "remove from old cp transaction");
1006 cp_transaction->t_chp_stats.cs_dropped++;
1007 __jbd2_journal_remove_checkpoint(jh);
1008 }
1009
1010 /* Only re-checkpoint the buffer_head if it is marked
1011 * dirty. If the buffer was added to the BJ_Forget list
1012 * by jbd2_journal_forget, it may no longer be dirty and
1013 * there's no point in keeping a checkpoint record for
1014 * it. */
1015
1016 /*
1017 * A buffer which has been freed while still being journaled
1018 * by a previous transaction, refile the buffer to BJ_Forget of
1019 * the running transaction. If the just committed transaction
1020 * contains "add to orphan" operation, we can completely
1021 * invalidate the buffer now. We are rather through in that
1022 * since the buffer may be still accessible when blocksize <
1023 * pagesize and it is attached to the last partial page.
1024 */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 struct address_space *mapping;
1027
1028 clear_buffer_freed(bh);
1029 clear_buffer_jbddirty(bh);
1030
1031 /*
1032 * Block device buffers need to stay mapped all the
1033 * time, so it is enough to clear buffer_jbddirty and
1034 * buffer_freed bits. For the file mapping buffers (i.e.
1035 * journalled data) we need to unmap buffer and clear
1036 * more bits. We also need to be careful about the check
1037 * because the data page mapping can get cleared under
1038 * our hands. Note that if mapping == NULL, we don't
1039 * need to make buffer unmapped because the page is
1040 * already detached from the mapping and buffers cannot
1041 * get reused.
1042 */
1043 mapping = READ_ONCE(bh->b_page->mapping);
1044 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1045 clear_buffer_mapped(bh);
1046 clear_buffer_new(bh);
1047 clear_buffer_req(bh);
1048 bh->b_bdev = NULL;
1049 }
1050 }
1051
1052 if (buffer_jbddirty(bh)) {
1053 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1054 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1055 if (is_journal_aborted(journal))
1056 clear_buffer_jbddirty(bh);
1057 } else {
1058 J_ASSERT_BH(bh, !buffer_dirty(bh));
1059 /*
1060 * The buffer on BJ_Forget list and not jbddirty means
1061 * it has been freed by this transaction and hence it
1062 * could not have been reallocated until this
1063 * transaction has committed. *BUT* it could be
1064 * reallocated once we have written all the data to
1065 * disk and before we process the buffer on BJ_Forget
1066 * list.
1067 */
1068 if (!jh->b_next_transaction)
1069 try_to_free = 1;
1070 }
1071 JBUFFER_TRACE(jh, "refile or unfile buffer");
1072 drop_ref = __jbd2_journal_refile_buffer(jh);
1073 spin_unlock(&jh->b_state_lock);
1074 if (drop_ref)
1075 jbd2_journal_put_journal_head(jh);
1076 if (try_to_free)
1077 release_buffer_page(bh); /* Drops bh reference */
1078 else
1079 __brelse(bh);
1080 cond_resched_lock(&journal->j_list_lock);
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083 /*
1084 * This is a bit sleazy. We use j_list_lock to protect transition
1085 * of a transaction into T_FINISHED state and calling
1086 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1087 * other checkpointing code processing the transaction...
1088 */
1089 write_lock(&journal->j_state_lock);
1090 spin_lock(&journal->j_list_lock);
1091 /*
1092 * Now recheck if some buffers did not get attached to the transaction
1093 * while the lock was dropped...
1094 */
1095 if (commit_transaction->t_forget) {
1096 spin_unlock(&journal->j_list_lock);
1097 write_unlock(&journal->j_state_lock);
1098 goto restart_loop;
1099 }
1100
1101 /* Add the transaction to the checkpoint list
1102 * __journal_remove_checkpoint() can not destroy transaction
1103 * under us because it is not marked as T_FINISHED yet */
1104 if (journal->j_checkpoint_transactions == NULL) {
1105 journal->j_checkpoint_transactions = commit_transaction;
1106 commit_transaction->t_cpnext = commit_transaction;
1107 commit_transaction->t_cpprev = commit_transaction;
1108 } else {
1109 commit_transaction->t_cpnext =
1110 journal->j_checkpoint_transactions;
1111 commit_transaction->t_cpprev =
1112 commit_transaction->t_cpnext->t_cpprev;
1113 commit_transaction->t_cpnext->t_cpprev =
1114 commit_transaction;
1115 commit_transaction->t_cpprev->t_cpnext =
1116 commit_transaction;
1117 }
1118 spin_unlock(&journal->j_list_lock);
1119
1120 /* Done with this transaction! */
1121
1122 jbd2_debug(3, "JBD2: commit phase 7\n");
1123
1124 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1125
1126 commit_transaction->t_start = jiffies;
1127 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1128 commit_transaction->t_start);
1129
1130 /*
1131 * File the transaction statistics
1132 */
1133 stats.ts_tid = commit_transaction->t_tid;
1134 stats.run.rs_handle_count =
1135 atomic_read(&commit_transaction->t_handle_count);
1136 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1137 commit_transaction->t_tid, &stats.run);
1138 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1139
1140 commit_transaction->t_state = T_COMMIT_CALLBACK;
1141 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1142 journal->j_commit_sequence = commit_transaction->t_tid;
1143 journal->j_committing_transaction = NULL;
1144 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1145
1146 /*
1147 * weight the commit time higher than the average time so we don't
1148 * react too strongly to vast changes in the commit time
1149 */
1150 if (likely(journal->j_average_commit_time))
1151 journal->j_average_commit_time = (commit_time +
1152 journal->j_average_commit_time*3) / 4;
1153 else
1154 journal->j_average_commit_time = commit_time;
1155
1156 write_unlock(&journal->j_state_lock);
1157
1158 if (journal->j_commit_callback)
1159 journal->j_commit_callback(journal, commit_transaction);
1160 if (journal->j_fc_cleanup_callback)
1161 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1162
1163 trace_jbd2_end_commit(journal, commit_transaction);
1164 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1165 journal->j_commit_sequence, journal->j_tail_sequence);
1166
1167 write_lock(&journal->j_state_lock);
1168 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1169 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1170 spin_lock(&journal->j_list_lock);
1171 commit_transaction->t_state = T_FINISHED;
1172 /* Check if the transaction can be dropped now that we are finished */
1173 if (commit_transaction->t_checkpoint_list == NULL &&
1174 commit_transaction->t_checkpoint_io_list == NULL) {
1175 __jbd2_journal_drop_transaction(journal, commit_transaction);
1176 jbd2_journal_free_transaction(commit_transaction);
1177 }
1178 spin_unlock(&journal->j_list_lock);
1179 write_unlock(&journal->j_state_lock);
1180 wake_up(&journal->j_wait_done_commit);
1181 wake_up(&journal->j_fc_wait);
1182
1183 /*
1184 * Calculate overall stats
1185 */
1186 spin_lock(&journal->j_history_lock);
1187 journal->j_stats.ts_tid++;
1188 journal->j_stats.ts_requested += stats.ts_requested;
1189 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1190 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1191 journal->j_stats.run.rs_running += stats.run.rs_running;
1192 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1193 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1194 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1195 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1196 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1197 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1198 spin_unlock(&journal->j_history_lock);
1199}
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}