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 */
32 static 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 */
63 static 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
86 nope:
87 __brelse(bh);
88 }
89
90 static 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 */
114 static 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 */
165 static 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 */
181 int 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 }
190 EXPORT_SYMBOL(jbd2_submit_inode_data);
191
192 int 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 }
201 EXPORT_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 */
211 static 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
240 int 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 */
254 static 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
300 static __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
312 static 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
320 static 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 */
348 void 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 if (escape < 0) {
666 jbd2_journal_abort(journal, escape);
667 continue;
668 }
669 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
670
671 /* Record the new block's tag in the current descriptor
672 buffer */
673
674 tag_flag = 0;
675 if (escape)
676 tag_flag |= JBD2_FLAG_ESCAPE;
677 if (!first_tag)
678 tag_flag |= JBD2_FLAG_SAME_UUID;
679
680 tag = (journal_block_tag_t *) tagp;
681 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
682 tag->t_flags = cpu_to_be16(tag_flag);
683 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
684 commit_transaction->t_tid);
685 tagp += tag_bytes;
686 space_left -= tag_bytes;
687 bufs++;
688
689 if (first_tag) {
690 memcpy (tagp, journal->j_uuid, 16);
691 tagp += 16;
692 space_left -= 16;
693 first_tag = 0;
694 }
695
696 /* If there's no more to do, or if the descriptor is full,
697 let the IO rip! */
698
699 if (bufs == journal->j_wbufsize ||
700 commit_transaction->t_buffers == NULL ||
701 space_left < tag_bytes + 16 + csum_size) {
702
703 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
704
705 /* Write an end-of-descriptor marker before
706 submitting the IOs. "tag" still points to
707 the last tag we set up. */
708
709 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
710 start_journal_io:
711 if (descriptor)
712 jbd2_descriptor_block_csum_set(journal,
713 descriptor);
714
715 for (i = 0; i < bufs; i++) {
716 struct buffer_head *bh = wbuf[i];
717
718 /*
719 * Compute checksum.
720 */
721 if (jbd2_has_feature_checksum(journal)) {
722 crc32_sum =
723 jbd2_checksum_data(crc32_sum, bh);
724 }
725
726 lock_buffer(bh);
727 clear_buffer_dirty(bh);
728 set_buffer_uptodate(bh);
729 bh->b_end_io = journal_end_buffer_io_sync;
730 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
731 bh);
732 }
733 cond_resched();
734
735 /* Force a new descriptor to be generated next
736 time round the loop. */
737 descriptor = NULL;
738 bufs = 0;
739 }
740 }
741
742 err = journal_finish_inode_data_buffers(journal, commit_transaction);
743 if (err) {
744 printk(KERN_WARNING
745 "JBD2: Detected IO errors while flushing file data "
746 "on %s\n", journal->j_devname);
747 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
748 jbd2_journal_abort(journal, err);
749 err = 0;
750 }
751
752 /*
753 * Get current oldest transaction in the log before we issue flush
754 * to the filesystem device. After the flush we can be sure that
755 * blocks of all older transactions are checkpointed to persistent
756 * storage and we will be safe to update journal start in the
757 * superblock with the numbers we get here.
758 */
759 update_tail =
760 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
761
762 write_lock(&journal->j_state_lock);
763 if (update_tail) {
764 long freed = first_block - journal->j_tail;
765
766 if (first_block < journal->j_tail)
767 freed += journal->j_last - journal->j_first;
768 /* Update tail only if we free significant amount of space */
769 if (freed < journal->j_max_transaction_buffers)
770 update_tail = 0;
771 }
772 J_ASSERT(commit_transaction->t_state == T_COMMIT);
773 commit_transaction->t_state = T_COMMIT_DFLUSH;
774 write_unlock(&journal->j_state_lock);
775
776 /*
777 * If the journal is not located on the file system device,
778 * then we must flush the file system device before we issue
779 * the commit record
780 */
781 if (commit_transaction->t_need_data_flush &&
782 (journal->j_fs_dev != journal->j_dev) &&
783 (journal->j_flags & JBD2_BARRIER))
784 blkdev_issue_flush(journal->j_fs_dev);
785
786 /* Done it all: now write the commit record asynchronously. */
787 if (jbd2_has_feature_async_commit(journal)) {
788 err = journal_submit_commit_record(journal, commit_transaction,
789 &cbh, crc32_sum);
790 if (err)
791 jbd2_journal_abort(journal, err);
792 }
793
794 blk_finish_plug(&plug);
795
796 /* Lo and behold: we have just managed to send a transaction to
797 the log. Before we can commit it, wait for the IO so far to
798 complete. Control buffers being written are on the
799 transaction's t_log_list queue, and metadata buffers are on
800 the io_bufs list.
801
802 Wait for the buffers in reverse order. That way we are
803 less likely to be woken up until all IOs have completed, and
804 so we incur less scheduling load.
805 */
806
807 jbd2_debug(3, "JBD2: commit phase 3\n");
808
809 while (!list_empty(&io_bufs)) {
810 struct buffer_head *bh = list_entry(io_bufs.prev,
811 struct buffer_head,
812 b_assoc_buffers);
813
814 wait_on_buffer(bh);
815 cond_resched();
816
817 if (unlikely(!buffer_uptodate(bh)))
818 err = -EIO;
819 jbd2_unfile_log_bh(bh);
820 stats.run.rs_blocks_logged++;
821
822 /*
823 * The list contains temporary buffer heads created by
824 * jbd2_journal_write_metadata_buffer().
825 */
826 BUFFER_TRACE(bh, "dumping temporary bh");
827 __brelse(bh);
828 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
829 free_buffer_head(bh);
830
831 /* We also have to refile the corresponding shadowed buffer */
832 jh = commit_transaction->t_shadow_list->b_tprev;
833 bh = jh2bh(jh);
834 clear_buffer_jwrite(bh);
835 J_ASSERT_BH(bh, buffer_jbddirty(bh));
836 J_ASSERT_BH(bh, !buffer_shadow(bh));
837
838 /* The metadata is now released for reuse, but we need
839 to remember it against this transaction so that when
840 we finally commit, we can do any checkpointing
841 required. */
842 JBUFFER_TRACE(jh, "file as BJ_Forget");
843 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
844 JBUFFER_TRACE(jh, "brelse shadowed buffer");
845 __brelse(bh);
846 }
847
848 J_ASSERT (commit_transaction->t_shadow_list == NULL);
849
850 jbd2_debug(3, "JBD2: commit phase 4\n");
851
852 /* Here we wait for the revoke record and descriptor record buffers */
853 while (!list_empty(&log_bufs)) {
854 struct buffer_head *bh;
855
856 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
857 wait_on_buffer(bh);
858 cond_resched();
859
860 if (unlikely(!buffer_uptodate(bh)))
861 err = -EIO;
862
863 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
864 clear_buffer_jwrite(bh);
865 jbd2_unfile_log_bh(bh);
866 stats.run.rs_blocks_logged++;
867 __brelse(bh); /* One for getblk */
868 /* AKPM: bforget here */
869 }
870
871 if (err)
872 jbd2_journal_abort(journal, err);
873
874 jbd2_debug(3, "JBD2: commit phase 5\n");
875 write_lock(&journal->j_state_lock);
876 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
877 commit_transaction->t_state = T_COMMIT_JFLUSH;
878 write_unlock(&journal->j_state_lock);
879
880 if (!jbd2_has_feature_async_commit(journal)) {
881 err = journal_submit_commit_record(journal, commit_transaction,
882 &cbh, crc32_sum);
883 if (err)
884 jbd2_journal_abort(journal, err);
885 }
886 if (cbh)
887 err = journal_wait_on_commit_record(journal, cbh);
888 stats.run.rs_blocks_logged++;
889 if (jbd2_has_feature_async_commit(journal) &&
890 journal->j_flags & JBD2_BARRIER) {
891 blkdev_issue_flush(journal->j_dev);
892 }
893
894 if (err)
895 jbd2_journal_abort(journal, err);
896
897 WARN_ON_ONCE(
898 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
899
900 /*
901 * Now disk caches for filesystem device are flushed so we are safe to
902 * erase checkpointed transactions from the log by updating journal
903 * superblock.
904 */
905 if (update_tail)
906 jbd2_update_log_tail(journal, first_tid, first_block);
907
908 /* End of a transaction! Finally, we can do checkpoint
909 processing: any buffers committed as a result of this
910 transaction can be removed from any checkpoint list it was on
911 before. */
912
913 jbd2_debug(3, "JBD2: commit phase 6\n");
914
915 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
916 J_ASSERT(commit_transaction->t_buffers == NULL);
917 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
918 J_ASSERT(commit_transaction->t_shadow_list == NULL);
919
920 restart_loop:
921 /*
922 * As there are other places (journal_unmap_buffer()) adding buffers
923 * to this list we have to be careful and hold the j_list_lock.
924 */
925 spin_lock(&journal->j_list_lock);
926 while (commit_transaction->t_forget) {
927 transaction_t *cp_transaction;
928 struct buffer_head *bh;
929 int try_to_free = 0;
930 bool drop_ref;
931
932 jh = commit_transaction->t_forget;
933 spin_unlock(&journal->j_list_lock);
934 bh = jh2bh(jh);
935 /*
936 * Get a reference so that bh cannot be freed before we are
937 * done with it.
938 */
939 get_bh(bh);
940 spin_lock(&jh->b_state_lock);
941 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
942
943 /*
944 * If there is undo-protected committed data against
945 * this buffer, then we can remove it now. If it is a
946 * buffer needing such protection, the old frozen_data
947 * field now points to a committed version of the
948 * buffer, so rotate that field to the new committed
949 * data.
950 *
951 * Otherwise, we can just throw away the frozen data now.
952 *
953 * We also know that the frozen data has already fired
954 * its triggers if they exist, so we can clear that too.
955 */
956 if (jh->b_committed_data) {
957 jbd2_free(jh->b_committed_data, bh->b_size);
958 jh->b_committed_data = NULL;
959 if (jh->b_frozen_data) {
960 jh->b_committed_data = jh->b_frozen_data;
961 jh->b_frozen_data = NULL;
962 jh->b_frozen_triggers = NULL;
963 }
964 } else if (jh->b_frozen_data) {
965 jbd2_free(jh->b_frozen_data, bh->b_size);
966 jh->b_frozen_data = NULL;
967 jh->b_frozen_triggers = NULL;
968 }
969
970 spin_lock(&journal->j_list_lock);
971 cp_transaction = jh->b_cp_transaction;
972 if (cp_transaction) {
973 JBUFFER_TRACE(jh, "remove from old cp transaction");
974 cp_transaction->t_chp_stats.cs_dropped++;
975 __jbd2_journal_remove_checkpoint(jh);
976 }
977
978 /* Only re-checkpoint the buffer_head if it is marked
979 * dirty. If the buffer was added to the BJ_Forget list
980 * by jbd2_journal_forget, it may no longer be dirty and
981 * there's no point in keeping a checkpoint record for
982 * it. */
983
984 /*
985 * A buffer which has been freed while still being journaled
986 * by a previous transaction, refile the buffer to BJ_Forget of
987 * the running transaction. If the just committed transaction
988 * contains "add to orphan" operation, we can completely
989 * invalidate the buffer now. We are rather through in that
990 * since the buffer may be still accessible when blocksize <
991 * pagesize and it is attached to the last partial page.
992 */
993 if (buffer_freed(bh) && !jh->b_next_transaction) {
994 struct address_space *mapping;
995
996 clear_buffer_freed(bh);
997 clear_buffer_jbddirty(bh);
998
999 /*
1000 * Block device buffers need to stay mapped all the
1001 * time, so it is enough to clear buffer_jbddirty and
1002 * buffer_freed bits. For the file mapping buffers (i.e.
1003 * journalled data) we need to unmap buffer and clear
1004 * more bits. We also need to be careful about the check
1005 * because the data page mapping can get cleared under
1006 * our hands. Note that if mapping == NULL, we don't
1007 * need to make buffer unmapped because the page is
1008 * already detached from the mapping and buffers cannot
1009 * get reused.
1010 */
1011 mapping = READ_ONCE(bh->b_folio->mapping);
1012 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1013 clear_buffer_mapped(bh);
1014 clear_buffer_new(bh);
1015 clear_buffer_req(bh);
1016 bh->b_bdev = NULL;
1017 }
1018 }
1019
1020 if (buffer_jbddirty(bh)) {
1021 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1022 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1023 if (is_journal_aborted(journal))
1024 clear_buffer_jbddirty(bh);
1025 } else {
1026 J_ASSERT_BH(bh, !buffer_dirty(bh));
1027 /*
1028 * The buffer on BJ_Forget list and not jbddirty means
1029 * it has been freed by this transaction and hence it
1030 * could not have been reallocated until this
1031 * transaction has committed. *BUT* it could be
1032 * reallocated once we have written all the data to
1033 * disk and before we process the buffer on BJ_Forget
1034 * list.
1035 */
1036 if (!jh->b_next_transaction)
1037 try_to_free = 1;
1038 }
1039 JBUFFER_TRACE(jh, "refile or unfile buffer");
1040 drop_ref = __jbd2_journal_refile_buffer(jh);
1041 spin_unlock(&jh->b_state_lock);
1042 if (drop_ref)
1043 jbd2_journal_put_journal_head(jh);
1044 if (try_to_free)
1045 release_buffer_page(bh); /* Drops bh reference */
1046 else
1047 __brelse(bh);
1048 cond_resched_lock(&journal->j_list_lock);
1049 }
1050 spin_unlock(&journal->j_list_lock);
1051 /*
1052 * This is a bit sleazy. We use j_list_lock to protect transition
1053 * of a transaction into T_FINISHED state and calling
1054 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1055 * other checkpointing code processing the transaction...
1056 */
1057 write_lock(&journal->j_state_lock);
1058 spin_lock(&journal->j_list_lock);
1059 /*
1060 * Now recheck if some buffers did not get attached to the transaction
1061 * while the lock was dropped...
1062 */
1063 if (commit_transaction->t_forget) {
1064 spin_unlock(&journal->j_list_lock);
1065 write_unlock(&journal->j_state_lock);
1066 goto restart_loop;
1067 }
1068
1069 /* Add the transaction to the checkpoint list
1070 * __journal_remove_checkpoint() can not destroy transaction
1071 * under us because it is not marked as T_FINISHED yet */
1072 if (journal->j_checkpoint_transactions == NULL) {
1073 journal->j_checkpoint_transactions = commit_transaction;
1074 commit_transaction->t_cpnext = commit_transaction;
1075 commit_transaction->t_cpprev = commit_transaction;
1076 } else {
1077 commit_transaction->t_cpnext =
1078 journal->j_checkpoint_transactions;
1079 commit_transaction->t_cpprev =
1080 commit_transaction->t_cpnext->t_cpprev;
1081 commit_transaction->t_cpnext->t_cpprev =
1082 commit_transaction;
1083 commit_transaction->t_cpprev->t_cpnext =
1084 commit_transaction;
1085 }
1086 spin_unlock(&journal->j_list_lock);
1087
1088 /* Done with this transaction! */
1089
1090 jbd2_debug(3, "JBD2: commit phase 7\n");
1091
1092 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1093
1094 commit_transaction->t_start = jiffies;
1095 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1096 commit_transaction->t_start);
1097
1098 /*
1099 * File the transaction statistics
1100 */
1101 stats.ts_tid = commit_transaction->t_tid;
1102 stats.run.rs_handle_count =
1103 atomic_read(&commit_transaction->t_handle_count);
1104 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1105 commit_transaction->t_tid, &stats.run);
1106 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1107
1108 commit_transaction->t_state = T_COMMIT_CALLBACK;
1109 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1110 WRITE_ONCE(journal->j_commit_sequence, commit_transaction->t_tid);
1111 journal->j_committing_transaction = NULL;
1112 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1113
1114 /*
1115 * weight the commit time higher than the average time so we don't
1116 * react too strongly to vast changes in the commit time
1117 */
1118 if (likely(journal->j_average_commit_time))
1119 journal->j_average_commit_time = (commit_time +
1120 journal->j_average_commit_time*3) / 4;
1121 else
1122 journal->j_average_commit_time = commit_time;
1123
1124 write_unlock(&journal->j_state_lock);
1125
1126 if (journal->j_commit_callback)
1127 journal->j_commit_callback(journal, commit_transaction);
1128 if (journal->j_fc_cleanup_callback)
1129 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1130
1131 trace_jbd2_end_commit(journal, commit_transaction);
1132 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1133 journal->j_commit_sequence, journal->j_tail_sequence);
1134
1135 write_lock(&journal->j_state_lock);
1136 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1137 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1138 spin_lock(&journal->j_list_lock);
1139 commit_transaction->t_state = T_FINISHED;
1140 /* Check if the transaction can be dropped now that we are finished */
1141 if (commit_transaction->t_checkpoint_list == NULL) {
1142 __jbd2_journal_drop_transaction(journal, commit_transaction);
1143 jbd2_journal_free_transaction(commit_transaction);
1144 }
1145 spin_unlock(&journal->j_list_lock);
1146 write_unlock(&journal->j_state_lock);
1147 wake_up(&journal->j_wait_done_commit);
1148 wake_up(&journal->j_fc_wait);
1149
1150 /*
1151 * Calculate overall stats
1152 */
1153 spin_lock(&journal->j_history_lock);
1154 journal->j_stats.ts_tid++;
1155 journal->j_stats.ts_requested += stats.ts_requested;
1156 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1157 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1158 journal->j_stats.run.rs_running += stats.run.rs_running;
1159 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1160 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1161 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1162 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1163 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1164 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1165 spin_unlock(&journal->j_history_lock);
1166 }
1167
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