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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
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}
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 */
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(struct jbd2_inode *jinode)
211{
212
213 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
214 return 0;
215
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 return jbd2_journal_submit_inode_data_buffers(jinode);
218
219}
220EXPORT_SYMBOL(jbd2_submit_inode_data);
221
222int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
223{
224 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
225 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
226 return 0;
227 return filemap_fdatawait_range_keep_errors(
228 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
229 jinode->i_dirty_end);
230}
231EXPORT_SYMBOL(jbd2_wait_inode_data);
232
233/*
234 * Submit all the data buffers of inode associated with the transaction to
235 * disk.
236 *
237 * We are in a committing transaction. Therefore no new inode can be added to
238 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
239 * operate on from being released while we write out pages.
240 */
241static int journal_submit_data_buffers(journal_t *journal,
242 transaction_t *commit_transaction)
243{
244 struct jbd2_inode *jinode;
245 int err, ret = 0;
246
247 spin_lock(&journal->j_list_lock);
248 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
249 if (!(jinode->i_flags & JI_WRITE_DATA))
250 continue;
251 jinode->i_flags |= JI_COMMIT_RUNNING;
252 spin_unlock(&journal->j_list_lock);
253 /* submit the inode data buffers. */
254 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
255 if (journal->j_submit_inode_data_buffers) {
256 err = journal->j_submit_inode_data_buffers(jinode);
257 if (!ret)
258 ret = err;
259 }
260 spin_lock(&journal->j_list_lock);
261 J_ASSERT(jinode->i_transaction == commit_transaction);
262 jinode->i_flags &= ~JI_COMMIT_RUNNING;
263 smp_mb();
264 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
265 }
266 spin_unlock(&journal->j_list_lock);
267 return ret;
268}
269
270int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
271{
272 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
273
274 return filemap_fdatawait_range_keep_errors(mapping,
275 jinode->i_dirty_start,
276 jinode->i_dirty_end);
277}
278
279/*
280 * Wait for data submitted for writeout, refile inodes to proper
281 * transaction if needed.
282 *
283 */
284static int journal_finish_inode_data_buffers(journal_t *journal,
285 transaction_t *commit_transaction)
286{
287 struct jbd2_inode *jinode, *next_i;
288 int err, ret = 0;
289
290 /* For locking, see the comment in journal_submit_data_buffers() */
291 spin_lock(&journal->j_list_lock);
292 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
293 if (!(jinode->i_flags & JI_WAIT_DATA))
294 continue;
295 jinode->i_flags |= JI_COMMIT_RUNNING;
296 spin_unlock(&journal->j_list_lock);
297 /* wait for the inode data buffers writeout. */
298 if (journal->j_finish_inode_data_buffers) {
299 err = journal->j_finish_inode_data_buffers(jinode);
300 if (!ret)
301 ret = err;
302 }
303 spin_lock(&journal->j_list_lock);
304 jinode->i_flags &= ~JI_COMMIT_RUNNING;
305 smp_mb();
306 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
307 }
308
309 /* Now refile inode to proper lists */
310 list_for_each_entry_safe(jinode, next_i,
311 &commit_transaction->t_inode_list, i_list) {
312 list_del(&jinode->i_list);
313 if (jinode->i_next_transaction) {
314 jinode->i_transaction = jinode->i_next_transaction;
315 jinode->i_next_transaction = NULL;
316 list_add(&jinode->i_list,
317 &jinode->i_transaction->t_inode_list);
318 } else {
319 jinode->i_transaction = NULL;
320 jinode->i_dirty_start = 0;
321 jinode->i_dirty_end = 0;
322 }
323 }
324 spin_unlock(&journal->j_list_lock);
325
326 return ret;
327}
328
329static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
330{
331 struct page *page = bh->b_page;
332 char *addr;
333 __u32 checksum;
334
335 addr = kmap_atomic(page);
336 checksum = crc32_be(crc32_sum,
337 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
338 kunmap_atomic(addr);
339
340 return checksum;
341}
342
343static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
344 unsigned long long block)
345{
346 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
347 if (jbd2_has_feature_64bit(j))
348 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
349}
350
351static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
352 struct buffer_head *bh, __u32 sequence)
353{
354 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
355 struct page *page = bh->b_page;
356 __u8 *addr;
357 __u32 csum32;
358 __be32 seq;
359
360 if (!jbd2_journal_has_csum_v2or3(j))
361 return;
362
363 seq = cpu_to_be32(sequence);
364 addr = kmap_atomic(page);
365 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
366 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
367 bh->b_size);
368 kunmap_atomic(addr);
369
370 if (jbd2_has_feature_csum3(j))
371 tag3->t_checksum = cpu_to_be32(csum32);
372 else
373 tag->t_checksum = cpu_to_be16(csum32);
374}
375/*
376 * jbd2_journal_commit_transaction
377 *
378 * The primary function for committing a transaction to the log. This
379 * function is called by the journal thread to begin a complete commit.
380 */
381void jbd2_journal_commit_transaction(journal_t *journal)
382{
383 struct transaction_stats_s stats;
384 transaction_t *commit_transaction;
385 struct journal_head *jh;
386 struct buffer_head *descriptor;
387 struct buffer_head **wbuf = journal->j_wbuf;
388 int bufs;
389 int flags;
390 int err;
391 unsigned long long blocknr;
392 ktime_t start_time;
393 u64 commit_time;
394 char *tagp = NULL;
395 journal_block_tag_t *tag = NULL;
396 int space_left = 0;
397 int first_tag = 0;
398 int tag_flag;
399 int i;
400 int tag_bytes = journal_tag_bytes(journal);
401 struct buffer_head *cbh = NULL; /* For transactional checksums */
402 __u32 crc32_sum = ~0;
403 struct blk_plug plug;
404 /* Tail of the journal */
405 unsigned long first_block;
406 tid_t first_tid;
407 int update_tail;
408 int csum_size = 0;
409 LIST_HEAD(io_bufs);
410 LIST_HEAD(log_bufs);
411
412 if (jbd2_journal_has_csum_v2or3(journal))
413 csum_size = sizeof(struct jbd2_journal_block_tail);
414
415 /*
416 * First job: lock down the current transaction and wait for
417 * all outstanding updates to complete.
418 */
419
420 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
421 if (journal->j_flags & JBD2_FLUSHED) {
422 jbd_debug(3, "super block updated\n");
423 mutex_lock_io(&journal->j_checkpoint_mutex);
424 /*
425 * We hold j_checkpoint_mutex so tail cannot change under us.
426 * We don't need any special data guarantees for writing sb
427 * since journal is empty and it is ok for write to be
428 * flushed only with transaction commit.
429 */
430 jbd2_journal_update_sb_log_tail(journal,
431 journal->j_tail_sequence,
432 journal->j_tail,
433 REQ_SYNC);
434 mutex_unlock(&journal->j_checkpoint_mutex);
435 } else {
436 jbd_debug(3, "superblock not updated\n");
437 }
438
439 J_ASSERT(journal->j_running_transaction != NULL);
440 J_ASSERT(journal->j_committing_transaction == NULL);
441
442 write_lock(&journal->j_state_lock);
443 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
444 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
445 DEFINE_WAIT(wait);
446
447 prepare_to_wait(&journal->j_fc_wait, &wait,
448 TASK_UNINTERRUPTIBLE);
449 write_unlock(&journal->j_state_lock);
450 schedule();
451 write_lock(&journal->j_state_lock);
452 finish_wait(&journal->j_fc_wait, &wait);
453 /*
454 * TODO: by blocking fast commits here, we are increasing
455 * fsync() latency slightly. Strictly speaking, we don't need
456 * to block fast commits until the transaction enters T_FLUSH
457 * state. So an optimization is possible where we block new fast
458 * commits here and wait for existing ones to complete
459 * just before we enter T_FLUSH. That way, the existing fast
460 * commits and this full commit can proceed parallely.
461 */
462 }
463 write_unlock(&journal->j_state_lock);
464
465 commit_transaction = journal->j_running_transaction;
466
467 trace_jbd2_start_commit(journal, commit_transaction);
468 jbd_debug(1, "JBD2: starting commit of transaction %d\n",
469 commit_transaction->t_tid);
470
471 write_lock(&journal->j_state_lock);
472 journal->j_fc_off = 0;
473 J_ASSERT(commit_transaction->t_state == T_RUNNING);
474 commit_transaction->t_state = T_LOCKED;
475
476 trace_jbd2_commit_locking(journal, commit_transaction);
477 stats.run.rs_wait = commit_transaction->t_max_wait;
478 stats.run.rs_request_delay = 0;
479 stats.run.rs_locked = jiffies;
480 if (commit_transaction->t_requested)
481 stats.run.rs_request_delay =
482 jbd2_time_diff(commit_transaction->t_requested,
483 stats.run.rs_locked);
484 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
485 stats.run.rs_locked);
486
487 spin_lock(&commit_transaction->t_handle_lock);
488 while (atomic_read(&commit_transaction->t_updates)) {
489 DEFINE_WAIT(wait);
490
491 prepare_to_wait(&journal->j_wait_updates, &wait,
492 TASK_UNINTERRUPTIBLE);
493 if (atomic_read(&commit_transaction->t_updates)) {
494 spin_unlock(&commit_transaction->t_handle_lock);
495 write_unlock(&journal->j_state_lock);
496 schedule();
497 write_lock(&journal->j_state_lock);
498 spin_lock(&commit_transaction->t_handle_lock);
499 }
500 finish_wait(&journal->j_wait_updates, &wait);
501 }
502 spin_unlock(&commit_transaction->t_handle_lock);
503 commit_transaction->t_state = T_SWITCH;
504 write_unlock(&journal->j_state_lock);
505
506 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
507 journal->j_max_transaction_buffers);
508
509 /*
510 * First thing we are allowed to do is to discard any remaining
511 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
512 * that there are no such buffers: if a large filesystem
513 * operation like a truncate needs to split itself over multiple
514 * transactions, then it may try to do a jbd2_journal_restart() while
515 * there are still BJ_Reserved buffers outstanding. These must
516 * be released cleanly from the current transaction.
517 *
518 * In this case, the filesystem must still reserve write access
519 * again before modifying the buffer in the new transaction, but
520 * we do not require it to remember exactly which old buffers it
521 * has reserved. This is consistent with the existing behaviour
522 * that multiple jbd2_journal_get_write_access() calls to the same
523 * buffer are perfectly permissible.
524 */
525 while (commit_transaction->t_reserved_list) {
526 jh = commit_transaction->t_reserved_list;
527 JBUFFER_TRACE(jh, "reserved, unused: refile");
528 /*
529 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
530 * leave undo-committed data.
531 */
532 if (jh->b_committed_data) {
533 struct buffer_head *bh = jh2bh(jh);
534
535 spin_lock(&jh->b_state_lock);
536 jbd2_free(jh->b_committed_data, bh->b_size);
537 jh->b_committed_data = NULL;
538 spin_unlock(&jh->b_state_lock);
539 }
540 jbd2_journal_refile_buffer(journal, jh);
541 }
542
543 /*
544 * Now try to drop any written-back buffers from the journal's
545 * checkpoint lists. We do this *before* commit because it potentially
546 * frees some memory
547 */
548 spin_lock(&journal->j_list_lock);
549 __jbd2_journal_clean_checkpoint_list(journal, false);
550 spin_unlock(&journal->j_list_lock);
551
552 jbd_debug(3, "JBD2: commit phase 1\n");
553
554 /*
555 * Clear revoked flag to reflect there is no revoked buffers
556 * in the next transaction which is going to be started.
557 */
558 jbd2_clear_buffer_revoked_flags(journal);
559
560 /*
561 * Switch to a new revoke table.
562 */
563 jbd2_journal_switch_revoke_table(journal);
564
565 /*
566 * Reserved credits cannot be claimed anymore, free them
567 */
568 atomic_sub(atomic_read(&journal->j_reserved_credits),
569 &commit_transaction->t_outstanding_credits);
570
571 write_lock(&journal->j_state_lock);
572 trace_jbd2_commit_flushing(journal, commit_transaction);
573 stats.run.rs_flushing = jiffies;
574 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
575 stats.run.rs_flushing);
576
577 commit_transaction->t_state = T_FLUSH;
578 journal->j_committing_transaction = commit_transaction;
579 journal->j_running_transaction = NULL;
580 start_time = ktime_get();
581 commit_transaction->t_log_start = journal->j_head;
582 wake_up(&journal->j_wait_transaction_locked);
583 write_unlock(&journal->j_state_lock);
584
585 jbd_debug(3, "JBD2: commit phase 2a\n");
586
587 /*
588 * Now start flushing things to disk, in the order they appear
589 * on the transaction lists. Data blocks go first.
590 */
591 err = journal_submit_data_buffers(journal, commit_transaction);
592 if (err)
593 jbd2_journal_abort(journal, err);
594
595 blk_start_plug(&plug);
596 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
597
598 jbd_debug(3, "JBD2: commit phase 2b\n");
599
600 /*
601 * Way to go: we have now written out all of the data for a
602 * transaction! Now comes the tricky part: we need to write out
603 * metadata. Loop over the transaction's entire buffer list:
604 */
605 write_lock(&journal->j_state_lock);
606 commit_transaction->t_state = T_COMMIT;
607 write_unlock(&journal->j_state_lock);
608
609 trace_jbd2_commit_logging(journal, commit_transaction);
610 stats.run.rs_logging = jiffies;
611 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
612 stats.run.rs_logging);
613 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
614 stats.run.rs_blocks_logged = 0;
615
616 J_ASSERT(commit_transaction->t_nr_buffers <=
617 atomic_read(&commit_transaction->t_outstanding_credits));
618
619 err = 0;
620 bufs = 0;
621 descriptor = NULL;
622 while (commit_transaction->t_buffers) {
623
624 /* Find the next buffer to be journaled... */
625
626 jh = commit_transaction->t_buffers;
627
628 /* If we're in abort mode, we just un-journal the buffer and
629 release it. */
630
631 if (is_journal_aborted(journal)) {
632 clear_buffer_jbddirty(jh2bh(jh));
633 JBUFFER_TRACE(jh, "journal is aborting: refile");
634 jbd2_buffer_abort_trigger(jh,
635 jh->b_frozen_data ?
636 jh->b_frozen_triggers :
637 jh->b_triggers);
638 jbd2_journal_refile_buffer(journal, jh);
639 /* If that was the last one, we need to clean up
640 * any descriptor buffers which may have been
641 * already allocated, even if we are now
642 * aborting. */
643 if (!commit_transaction->t_buffers)
644 goto start_journal_io;
645 continue;
646 }
647
648 /* Make sure we have a descriptor block in which to
649 record the metadata buffer. */
650
651 if (!descriptor) {
652 J_ASSERT (bufs == 0);
653
654 jbd_debug(4, "JBD2: get descriptor\n");
655
656 descriptor = jbd2_journal_get_descriptor_buffer(
657 commit_transaction,
658 JBD2_DESCRIPTOR_BLOCK);
659 if (!descriptor) {
660 jbd2_journal_abort(journal, -EIO);
661 continue;
662 }
663
664 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
665 (unsigned long long)descriptor->b_blocknr,
666 descriptor->b_data);
667 tagp = &descriptor->b_data[sizeof(journal_header_t)];
668 space_left = descriptor->b_size -
669 sizeof(journal_header_t);
670 first_tag = 1;
671 set_buffer_jwrite(descriptor);
672 set_buffer_dirty(descriptor);
673 wbuf[bufs++] = descriptor;
674
675 /* Record it so that we can wait for IO
676 completion later */
677 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
678 jbd2_file_log_bh(&log_bufs, descriptor);
679 }
680
681 /* Where is the buffer to be written? */
682
683 err = jbd2_journal_next_log_block(journal, &blocknr);
684 /* If the block mapping failed, just abandon the buffer
685 and repeat this loop: we'll fall into the
686 refile-on-abort condition above. */
687 if (err) {
688 jbd2_journal_abort(journal, err);
689 continue;
690 }
691
692 /*
693 * start_this_handle() uses t_outstanding_credits to determine
694 * the free space in the log.
695 */
696 atomic_dec(&commit_transaction->t_outstanding_credits);
697
698 /* Bump b_count to prevent truncate from stumbling over
699 the shadowed buffer! @@@ This can go if we ever get
700 rid of the shadow pairing of buffers. */
701 atomic_inc(&jh2bh(jh)->b_count);
702
703 /*
704 * Make a temporary IO buffer with which to write it out
705 * (this will requeue the metadata buffer to BJ_Shadow).
706 */
707 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
708 JBUFFER_TRACE(jh, "ph3: write metadata");
709 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
710 jh, &wbuf[bufs], blocknr);
711 if (flags < 0) {
712 jbd2_journal_abort(journal, flags);
713 continue;
714 }
715 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
716
717 /* Record the new block's tag in the current descriptor
718 buffer */
719
720 tag_flag = 0;
721 if (flags & 1)
722 tag_flag |= JBD2_FLAG_ESCAPE;
723 if (!first_tag)
724 tag_flag |= JBD2_FLAG_SAME_UUID;
725
726 tag = (journal_block_tag_t *) tagp;
727 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
728 tag->t_flags = cpu_to_be16(tag_flag);
729 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
730 commit_transaction->t_tid);
731 tagp += tag_bytes;
732 space_left -= tag_bytes;
733 bufs++;
734
735 if (first_tag) {
736 memcpy (tagp, journal->j_uuid, 16);
737 tagp += 16;
738 space_left -= 16;
739 first_tag = 0;
740 }
741
742 /* If there's no more to do, or if the descriptor is full,
743 let the IO rip! */
744
745 if (bufs == journal->j_wbufsize ||
746 commit_transaction->t_buffers == NULL ||
747 space_left < tag_bytes + 16 + csum_size) {
748
749 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
750
751 /* Write an end-of-descriptor marker before
752 submitting the IOs. "tag" still points to
753 the last tag we set up. */
754
755 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
756start_journal_io:
757 if (descriptor)
758 jbd2_descriptor_block_csum_set(journal,
759 descriptor);
760
761 for (i = 0; i < bufs; i++) {
762 struct buffer_head *bh = wbuf[i];
763 /*
764 * Compute checksum.
765 */
766 if (jbd2_has_feature_checksum(journal)) {
767 crc32_sum =
768 jbd2_checksum_data(crc32_sum, bh);
769 }
770
771 lock_buffer(bh);
772 clear_buffer_dirty(bh);
773 set_buffer_uptodate(bh);
774 bh->b_end_io = journal_end_buffer_io_sync;
775 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
776 }
777 cond_resched();
778
779 /* Force a new descriptor to be generated next
780 time round the loop. */
781 descriptor = NULL;
782 bufs = 0;
783 }
784 }
785
786 err = journal_finish_inode_data_buffers(journal, commit_transaction);
787 if (err) {
788 printk(KERN_WARNING
789 "JBD2: Detected IO errors while flushing file data "
790 "on %s\n", journal->j_devname);
791 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
792 jbd2_journal_abort(journal, err);
793 err = 0;
794 }
795
796 /*
797 * Get current oldest transaction in the log before we issue flush
798 * to the filesystem device. After the flush we can be sure that
799 * blocks of all older transactions are checkpointed to persistent
800 * storage and we will be safe to update journal start in the
801 * superblock with the numbers we get here.
802 */
803 update_tail =
804 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
805
806 write_lock(&journal->j_state_lock);
807 if (update_tail) {
808 long freed = first_block - journal->j_tail;
809
810 if (first_block < journal->j_tail)
811 freed += journal->j_last - journal->j_first;
812 /* Update tail only if we free significant amount of space */
813 if (freed < jbd2_journal_get_max_txn_bufs(journal))
814 update_tail = 0;
815 }
816 J_ASSERT(commit_transaction->t_state == T_COMMIT);
817 commit_transaction->t_state = T_COMMIT_DFLUSH;
818 write_unlock(&journal->j_state_lock);
819
820 /*
821 * If the journal is not located on the file system device,
822 * then we must flush the file system device before we issue
823 * the commit record
824 */
825 if (commit_transaction->t_need_data_flush &&
826 (journal->j_fs_dev != journal->j_dev) &&
827 (journal->j_flags & JBD2_BARRIER))
828 blkdev_issue_flush(journal->j_fs_dev);
829
830 /* Done it all: now write the commit record asynchronously. */
831 if (jbd2_has_feature_async_commit(journal)) {
832 err = journal_submit_commit_record(journal, commit_transaction,
833 &cbh, crc32_sum);
834 if (err)
835 jbd2_journal_abort(journal, err);
836 }
837
838 blk_finish_plug(&plug);
839
840 /* Lo and behold: we have just managed to send a transaction to
841 the log. Before we can commit it, wait for the IO so far to
842 complete. Control buffers being written are on the
843 transaction's t_log_list queue, and metadata buffers are on
844 the io_bufs list.
845
846 Wait for the buffers in reverse order. That way we are
847 less likely to be woken up until all IOs have completed, and
848 so we incur less scheduling load.
849 */
850
851 jbd_debug(3, "JBD2: commit phase 3\n");
852
853 while (!list_empty(&io_bufs)) {
854 struct buffer_head *bh = list_entry(io_bufs.prev,
855 struct buffer_head,
856 b_assoc_buffers);
857
858 wait_on_buffer(bh);
859 cond_resched();
860
861 if (unlikely(!buffer_uptodate(bh)))
862 err = -EIO;
863 jbd2_unfile_log_bh(bh);
864 stats.run.rs_blocks_logged++;
865
866 /*
867 * The list contains temporary buffer heads created by
868 * jbd2_journal_write_metadata_buffer().
869 */
870 BUFFER_TRACE(bh, "dumping temporary bh");
871 __brelse(bh);
872 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
873 free_buffer_head(bh);
874
875 /* We also have to refile the corresponding shadowed buffer */
876 jh = commit_transaction->t_shadow_list->b_tprev;
877 bh = jh2bh(jh);
878 clear_buffer_jwrite(bh);
879 J_ASSERT_BH(bh, buffer_jbddirty(bh));
880 J_ASSERT_BH(bh, !buffer_shadow(bh));
881
882 /* The metadata is now released for reuse, but we need
883 to remember it against this transaction so that when
884 we finally commit, we can do any checkpointing
885 required. */
886 JBUFFER_TRACE(jh, "file as BJ_Forget");
887 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
888 JBUFFER_TRACE(jh, "brelse shadowed buffer");
889 __brelse(bh);
890 }
891
892 J_ASSERT (commit_transaction->t_shadow_list == NULL);
893
894 jbd_debug(3, "JBD2: commit phase 4\n");
895
896 /* Here we wait for the revoke record and descriptor record buffers */
897 while (!list_empty(&log_bufs)) {
898 struct buffer_head *bh;
899
900 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
901 wait_on_buffer(bh);
902 cond_resched();
903
904 if (unlikely(!buffer_uptodate(bh)))
905 err = -EIO;
906
907 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
908 clear_buffer_jwrite(bh);
909 jbd2_unfile_log_bh(bh);
910 stats.run.rs_blocks_logged++;
911 __brelse(bh); /* One for getblk */
912 /* AKPM: bforget here */
913 }
914
915 if (err)
916 jbd2_journal_abort(journal, err);
917
918 jbd_debug(3, "JBD2: commit phase 5\n");
919 write_lock(&journal->j_state_lock);
920 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
921 commit_transaction->t_state = T_COMMIT_JFLUSH;
922 write_unlock(&journal->j_state_lock);
923
924 if (!jbd2_has_feature_async_commit(journal)) {
925 err = journal_submit_commit_record(journal, commit_transaction,
926 &cbh, crc32_sum);
927 if (err)
928 jbd2_journal_abort(journal, err);
929 }
930 if (cbh)
931 err = journal_wait_on_commit_record(journal, cbh);
932 stats.run.rs_blocks_logged++;
933 if (jbd2_has_feature_async_commit(journal) &&
934 journal->j_flags & JBD2_BARRIER) {
935 blkdev_issue_flush(journal->j_dev);
936 }
937
938 if (err)
939 jbd2_journal_abort(journal, err);
940
941 WARN_ON_ONCE(
942 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
943
944 /*
945 * Now disk caches for filesystem device are flushed so we are safe to
946 * erase checkpointed transactions from the log by updating journal
947 * superblock.
948 */
949 if (update_tail)
950 jbd2_update_log_tail(journal, first_tid, first_block);
951
952 /* End of a transaction! Finally, we can do checkpoint
953 processing: any buffers committed as a result of this
954 transaction can be removed from any checkpoint list it was on
955 before. */
956
957 jbd_debug(3, "JBD2: commit phase 6\n");
958
959 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
960 J_ASSERT(commit_transaction->t_buffers == NULL);
961 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
962 J_ASSERT(commit_transaction->t_shadow_list == NULL);
963
964restart_loop:
965 /*
966 * As there are other places (journal_unmap_buffer()) adding buffers
967 * to this list we have to be careful and hold the j_list_lock.
968 */
969 spin_lock(&journal->j_list_lock);
970 while (commit_transaction->t_forget) {
971 transaction_t *cp_transaction;
972 struct buffer_head *bh;
973 int try_to_free = 0;
974 bool drop_ref;
975
976 jh = commit_transaction->t_forget;
977 spin_unlock(&journal->j_list_lock);
978 bh = jh2bh(jh);
979 /*
980 * Get a reference so that bh cannot be freed before we are
981 * done with it.
982 */
983 get_bh(bh);
984 spin_lock(&jh->b_state_lock);
985 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
986
987 /*
988 * If there is undo-protected committed data against
989 * this buffer, then we can remove it now. If it is a
990 * buffer needing such protection, the old frozen_data
991 * field now points to a committed version of the
992 * buffer, so rotate that field to the new committed
993 * data.
994 *
995 * Otherwise, we can just throw away the frozen data now.
996 *
997 * We also know that the frozen data has already fired
998 * its triggers if they exist, so we can clear that too.
999 */
1000 if (jh->b_committed_data) {
1001 jbd2_free(jh->b_committed_data, bh->b_size);
1002 jh->b_committed_data = NULL;
1003 if (jh->b_frozen_data) {
1004 jh->b_committed_data = jh->b_frozen_data;
1005 jh->b_frozen_data = NULL;
1006 jh->b_frozen_triggers = NULL;
1007 }
1008 } else if (jh->b_frozen_data) {
1009 jbd2_free(jh->b_frozen_data, bh->b_size);
1010 jh->b_frozen_data = NULL;
1011 jh->b_frozen_triggers = NULL;
1012 }
1013
1014 spin_lock(&journal->j_list_lock);
1015 cp_transaction = jh->b_cp_transaction;
1016 if (cp_transaction) {
1017 JBUFFER_TRACE(jh, "remove from old cp transaction");
1018 cp_transaction->t_chp_stats.cs_dropped++;
1019 __jbd2_journal_remove_checkpoint(jh);
1020 }
1021
1022 /* Only re-checkpoint the buffer_head if it is marked
1023 * dirty. If the buffer was added to the BJ_Forget list
1024 * by jbd2_journal_forget, it may no longer be dirty and
1025 * there's no point in keeping a checkpoint record for
1026 * it. */
1027
1028 /*
1029 * A buffer which has been freed while still being journaled
1030 * by a previous transaction, refile the buffer to BJ_Forget of
1031 * the running transaction. If the just committed transaction
1032 * contains "add to orphan" operation, we can completely
1033 * invalidate the buffer now. We are rather through in that
1034 * since the buffer may be still accessible when blocksize <
1035 * pagesize and it is attached to the last partial page.
1036 */
1037 if (buffer_freed(bh) && !jh->b_next_transaction) {
1038 struct address_space *mapping;
1039
1040 clear_buffer_freed(bh);
1041 clear_buffer_jbddirty(bh);
1042
1043 /*
1044 * Block device buffers need to stay mapped all the
1045 * time, so it is enough to clear buffer_jbddirty and
1046 * buffer_freed bits. For the file mapping buffers (i.e.
1047 * journalled data) we need to unmap buffer and clear
1048 * more bits. We also need to be careful about the check
1049 * because the data page mapping can get cleared under
1050 * our hands. Note that if mapping == NULL, we don't
1051 * need to make buffer unmapped because the page is
1052 * already detached from the mapping and buffers cannot
1053 * get reused.
1054 */
1055 mapping = READ_ONCE(bh->b_page->mapping);
1056 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1057 clear_buffer_mapped(bh);
1058 clear_buffer_new(bh);
1059 clear_buffer_req(bh);
1060 bh->b_bdev = NULL;
1061 }
1062 }
1063
1064 if (buffer_jbddirty(bh)) {
1065 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1066 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1067 if (is_journal_aborted(journal))
1068 clear_buffer_jbddirty(bh);
1069 } else {
1070 J_ASSERT_BH(bh, !buffer_dirty(bh));
1071 /*
1072 * The buffer on BJ_Forget list and not jbddirty means
1073 * it has been freed by this transaction and hence it
1074 * could not have been reallocated until this
1075 * transaction has committed. *BUT* it could be
1076 * reallocated once we have written all the data to
1077 * disk and before we process the buffer on BJ_Forget
1078 * list.
1079 */
1080 if (!jh->b_next_transaction)
1081 try_to_free = 1;
1082 }
1083 JBUFFER_TRACE(jh, "refile or unfile buffer");
1084 drop_ref = __jbd2_journal_refile_buffer(jh);
1085 spin_unlock(&jh->b_state_lock);
1086 if (drop_ref)
1087 jbd2_journal_put_journal_head(jh);
1088 if (try_to_free)
1089 release_buffer_page(bh); /* Drops bh reference */
1090 else
1091 __brelse(bh);
1092 cond_resched_lock(&journal->j_list_lock);
1093 }
1094 spin_unlock(&journal->j_list_lock);
1095 /*
1096 * This is a bit sleazy. We use j_list_lock to protect transition
1097 * of a transaction into T_FINISHED state and calling
1098 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1099 * other checkpointing code processing the transaction...
1100 */
1101 write_lock(&journal->j_state_lock);
1102 spin_lock(&journal->j_list_lock);
1103 /*
1104 * Now recheck if some buffers did not get attached to the transaction
1105 * while the lock was dropped...
1106 */
1107 if (commit_transaction->t_forget) {
1108 spin_unlock(&journal->j_list_lock);
1109 write_unlock(&journal->j_state_lock);
1110 goto restart_loop;
1111 }
1112
1113 /* Add the transaction to the checkpoint list
1114 * __journal_remove_checkpoint() can not destroy transaction
1115 * under us because it is not marked as T_FINISHED yet */
1116 if (journal->j_checkpoint_transactions == NULL) {
1117 journal->j_checkpoint_transactions = commit_transaction;
1118 commit_transaction->t_cpnext = commit_transaction;
1119 commit_transaction->t_cpprev = commit_transaction;
1120 } else {
1121 commit_transaction->t_cpnext =
1122 journal->j_checkpoint_transactions;
1123 commit_transaction->t_cpprev =
1124 commit_transaction->t_cpnext->t_cpprev;
1125 commit_transaction->t_cpnext->t_cpprev =
1126 commit_transaction;
1127 commit_transaction->t_cpprev->t_cpnext =
1128 commit_transaction;
1129 }
1130 spin_unlock(&journal->j_list_lock);
1131
1132 /* Done with this transaction! */
1133
1134 jbd_debug(3, "JBD2: commit phase 7\n");
1135
1136 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1137
1138 commit_transaction->t_start = jiffies;
1139 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1140 commit_transaction->t_start);
1141
1142 /*
1143 * File the transaction statistics
1144 */
1145 stats.ts_tid = commit_transaction->t_tid;
1146 stats.run.rs_handle_count =
1147 atomic_read(&commit_transaction->t_handle_count);
1148 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1149 commit_transaction->t_tid, &stats.run);
1150 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1151
1152 commit_transaction->t_state = T_COMMIT_CALLBACK;
1153 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1154 journal->j_commit_sequence = commit_transaction->t_tid;
1155 journal->j_committing_transaction = NULL;
1156 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1157
1158 /*
1159 * weight the commit time higher than the average time so we don't
1160 * react too strongly to vast changes in the commit time
1161 */
1162 if (likely(journal->j_average_commit_time))
1163 journal->j_average_commit_time = (commit_time +
1164 journal->j_average_commit_time*3) / 4;
1165 else
1166 journal->j_average_commit_time = commit_time;
1167
1168 write_unlock(&journal->j_state_lock);
1169
1170 if (journal->j_commit_callback)
1171 journal->j_commit_callback(journal, commit_transaction);
1172 if (journal->j_fc_cleanup_callback)
1173 journal->j_fc_cleanup_callback(journal, 1);
1174
1175 trace_jbd2_end_commit(journal, commit_transaction);
1176 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1177 journal->j_commit_sequence, journal->j_tail_sequence);
1178
1179 write_lock(&journal->j_state_lock);
1180 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1181 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1182 spin_lock(&journal->j_list_lock);
1183 commit_transaction->t_state = T_FINISHED;
1184 /* Check if the transaction can be dropped now that we are finished */
1185 if (commit_transaction->t_checkpoint_list == NULL &&
1186 commit_transaction->t_checkpoint_io_list == NULL) {
1187 __jbd2_journal_drop_transaction(journal, commit_transaction);
1188 jbd2_journal_free_transaction(commit_transaction);
1189 }
1190 spin_unlock(&journal->j_list_lock);
1191 write_unlock(&journal->j_state_lock);
1192 wake_up(&journal->j_wait_done_commit);
1193 wake_up(&journal->j_fc_wait);
1194
1195 /*
1196 * Calculate overall stats
1197 */
1198 spin_lock(&journal->j_history_lock);
1199 journal->j_stats.ts_tid++;
1200 journal->j_stats.ts_requested += stats.ts_requested;
1201 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1202 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1203 journal->j_stats.run.rs_running += stats.run.rs_running;
1204 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1205 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1206 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1207 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1208 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1209 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1210 spin_unlock(&journal->j_history_lock);
1211}