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1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct folio *folio;
66 struct page *page;
67
68 if (buffer_dirty(bh))
69 goto nope;
70 if (atomic_read(&bh->b_count) != 1)
71 goto nope;
72 page = bh->b_page;
73 if (!page)
74 goto nope;
75 folio = page_folio(page);
76 if (folio->mapping)
77 goto nope;
78
79 /* OK, it's a truncated page */
80 if (!folio_trylock(folio))
81 goto nope;
82
83 folio_get(folio);
84 __brelse(bh);
85 try_to_free_buffers(folio);
86 folio_unlock(folio);
87 folio_put(folio);
88 return;
89
90nope:
91 __brelse(bh);
92}
93
94static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
95{
96 struct commit_header *h;
97 __u32 csum;
98
99 if (!jbd2_journal_has_csum_v2or3(j))
100 return;
101
102 h = (struct commit_header *)(bh->b_data);
103 h->h_chksum_type = 0;
104 h->h_chksum_size = 0;
105 h->h_chksum[0] = 0;
106 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
107 h->h_chksum[0] = cpu_to_be32(csum);
108}
109
110/*
111 * Done it all: now submit the commit record. We should have
112 * cleaned up our previous buffers by now, so if we are in abort
113 * mode we can now just skip the rest of the journal write
114 * entirely.
115 *
116 * Returns 1 if the journal needs to be aborted or 0 on success
117 */
118static int journal_submit_commit_record(journal_t *journal,
119 transaction_t *commit_transaction,
120 struct buffer_head **cbh,
121 __u32 crc32_sum)
122{
123 struct commit_header *tmp;
124 struct buffer_head *bh;
125 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | REQ_SYNC;
127
128 *cbh = NULL;
129
130 if (is_journal_aborted(journal))
131 return 0;
132
133 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
134 JBD2_COMMIT_BLOCK);
135 if (!bh)
136 return 1;
137
138 tmp = (struct commit_header *)bh->b_data;
139 ktime_get_coarse_real_ts64(&now);
140 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
141 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
142
143 if (jbd2_has_feature_checksum(journal)) {
144 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
145 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
146 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
147 }
148 jbd2_commit_block_csum_set(journal, bh);
149
150 BUFFER_TRACE(bh, "submit commit block");
151 lock_buffer(bh);
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
155
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 write_flags |= REQ_PREFLUSH | REQ_FUA;
159
160 submit_bh(write_flags, bh);
161 *cbh = bh;
162 return 0;
163}
164
165/*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
169static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171{
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182}
183
184/*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
190int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
191{
192 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
193 struct writeback_control wbc = {
194 .sync_mode = WB_SYNC_ALL,
195 .nr_to_write = mapping->nrpages * 2,
196 .range_start = jinode->i_dirty_start,
197 .range_end = jinode->i_dirty_end,
198 };
199
200 /*
201 * submit the inode data buffers. We use writepage
202 * instead of writepages. Because writepages can do
203 * block allocation with delalloc. We need to write
204 * only allocated blocks here.
205 */
206 return generic_writepages(mapping, &wbc);
207}
208
209/* Send all the data buffers related to an inode */
210int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
211{
212 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
213 return 0;
214
215 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
216 return journal->j_submit_inode_data_buffers(jinode);
217
218}
219EXPORT_SYMBOL(jbd2_submit_inode_data);
220
221int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
222{
223 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
224 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
225 return 0;
226 return filemap_fdatawait_range_keep_errors(
227 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
228 jinode->i_dirty_end);
229}
230EXPORT_SYMBOL(jbd2_wait_inode_data);
231
232/*
233 * Submit all the data buffers of inode associated with the transaction to
234 * disk.
235 *
236 * We are in a committing transaction. Therefore no new inode can be added to
237 * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
238 * operate on from being released while we write out pages.
239 */
240static int journal_submit_data_buffers(journal_t *journal,
241 transaction_t *commit_transaction)
242{
243 struct jbd2_inode *jinode;
244 int err, ret = 0;
245
246 spin_lock(&journal->j_list_lock);
247 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
248 if (!(jinode->i_flags & JI_WRITE_DATA))
249 continue;
250 jinode->i_flags |= JI_COMMIT_RUNNING;
251 spin_unlock(&journal->j_list_lock);
252 /* submit the inode data buffers. */
253 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
254 if (journal->j_submit_inode_data_buffers) {
255 err = journal->j_submit_inode_data_buffers(jinode);
256 if (!ret)
257 ret = err;
258 }
259 spin_lock(&journal->j_list_lock);
260 J_ASSERT(jinode->i_transaction == commit_transaction);
261 jinode->i_flags &= ~JI_COMMIT_RUNNING;
262 smp_mb();
263 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
264 }
265 spin_unlock(&journal->j_list_lock);
266 return ret;
267}
268
269int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
270{
271 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
272
273 return filemap_fdatawait_range_keep_errors(mapping,
274 jinode->i_dirty_start,
275 jinode->i_dirty_end);
276}
277
278/*
279 * Wait for data submitted for writeout, refile inodes to proper
280 * transaction if needed.
281 *
282 */
283static int journal_finish_inode_data_buffers(journal_t *journal,
284 transaction_t *commit_transaction)
285{
286 struct jbd2_inode *jinode, *next_i;
287 int err, ret = 0;
288
289 /* For locking, see the comment in journal_submit_data_buffers() */
290 spin_lock(&journal->j_list_lock);
291 list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
292 if (!(jinode->i_flags & JI_WAIT_DATA))
293 continue;
294 jinode->i_flags |= JI_COMMIT_RUNNING;
295 spin_unlock(&journal->j_list_lock);
296 /* wait for the inode data buffers writeout. */
297 if (journal->j_finish_inode_data_buffers) {
298 err = journal->j_finish_inode_data_buffers(jinode);
299 if (!ret)
300 ret = err;
301 }
302 spin_lock(&journal->j_list_lock);
303 jinode->i_flags &= ~JI_COMMIT_RUNNING;
304 smp_mb();
305 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
306 }
307
308 /* Now refile inode to proper lists */
309 list_for_each_entry_safe(jinode, next_i,
310 &commit_transaction->t_inode_list, i_list) {
311 list_del(&jinode->i_list);
312 if (jinode->i_next_transaction) {
313 jinode->i_transaction = jinode->i_next_transaction;
314 jinode->i_next_transaction = NULL;
315 list_add(&jinode->i_list,
316 &jinode->i_transaction->t_inode_list);
317 } else {
318 jinode->i_transaction = NULL;
319 jinode->i_dirty_start = 0;
320 jinode->i_dirty_end = 0;
321 }
322 }
323 spin_unlock(&journal->j_list_lock);
324
325 return ret;
326}
327
328static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
329{
330 struct page *page = bh->b_page;
331 char *addr;
332 __u32 checksum;
333
334 addr = kmap_atomic(page);
335 checksum = crc32_be(crc32_sum,
336 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
337 kunmap_atomic(addr);
338
339 return checksum;
340}
341
342static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
343 unsigned long long block)
344{
345 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
346 if (jbd2_has_feature_64bit(j))
347 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
348}
349
350static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
351 struct buffer_head *bh, __u32 sequence)
352{
353 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
354 struct page *page = bh->b_page;
355 __u8 *addr;
356 __u32 csum32;
357 __be32 seq;
358
359 if (!jbd2_journal_has_csum_v2or3(j))
360 return;
361
362 seq = cpu_to_be32(sequence);
363 addr = kmap_atomic(page);
364 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
365 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
366 bh->b_size);
367 kunmap_atomic(addr);
368
369 if (jbd2_has_feature_csum3(j))
370 tag3->t_checksum = cpu_to_be32(csum32);
371 else
372 tag->t_checksum = cpu_to_be16(csum32);
373}
374/*
375 * jbd2_journal_commit_transaction
376 *
377 * The primary function for committing a transaction to the log. This
378 * function is called by the journal thread to begin a complete commit.
379 */
380void jbd2_journal_commit_transaction(journal_t *journal)
381{
382 struct transaction_stats_s stats;
383 transaction_t *commit_transaction;
384 struct journal_head *jh;
385 struct buffer_head *descriptor;
386 struct buffer_head **wbuf = journal->j_wbuf;
387 int bufs;
388 int flags;
389 int err;
390 unsigned long long blocknr;
391 ktime_t start_time;
392 u64 commit_time;
393 char *tagp = NULL;
394 journal_block_tag_t *tag = NULL;
395 int space_left = 0;
396 int first_tag = 0;
397 int tag_flag;
398 int i;
399 int tag_bytes = journal_tag_bytes(journal);
400 struct buffer_head *cbh = NULL; /* For transactional checksums */
401 __u32 crc32_sum = ~0;
402 struct blk_plug plug;
403 /* Tail of the journal */
404 unsigned long first_block;
405 tid_t first_tid;
406 int update_tail;
407 int csum_size = 0;
408 LIST_HEAD(io_bufs);
409 LIST_HEAD(log_bufs);
410
411 if (jbd2_journal_has_csum_v2or3(journal))
412 csum_size = sizeof(struct jbd2_journal_block_tail);
413
414 /*
415 * First job: lock down the current transaction and wait for
416 * all outstanding updates to complete.
417 */
418
419 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
420 if (journal->j_flags & JBD2_FLUSHED) {
421 jbd2_debug(3, "super block updated\n");
422 mutex_lock_io(&journal->j_checkpoint_mutex);
423 /*
424 * We hold j_checkpoint_mutex so tail cannot change under us.
425 * We don't need any special data guarantees for writing sb
426 * since journal is empty and it is ok for write to be
427 * flushed only with transaction commit.
428 */
429 jbd2_journal_update_sb_log_tail(journal,
430 journal->j_tail_sequence,
431 journal->j_tail,
432 REQ_SYNC);
433 mutex_unlock(&journal->j_checkpoint_mutex);
434 } else {
435 jbd2_debug(3, "superblock not updated\n");
436 }
437
438 J_ASSERT(journal->j_running_transaction != NULL);
439 J_ASSERT(journal->j_committing_transaction == NULL);
440
441 write_lock(&journal->j_state_lock);
442 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
443 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
444 DEFINE_WAIT(wait);
445
446 prepare_to_wait(&journal->j_fc_wait, &wait,
447 TASK_UNINTERRUPTIBLE);
448 write_unlock(&journal->j_state_lock);
449 schedule();
450 write_lock(&journal->j_state_lock);
451 finish_wait(&journal->j_fc_wait, &wait);
452 /*
453 * TODO: by blocking fast commits here, we are increasing
454 * fsync() latency slightly. Strictly speaking, we don't need
455 * to block fast commits until the transaction enters T_FLUSH
456 * state. So an optimization is possible where we block new fast
457 * commits here and wait for existing ones to complete
458 * just before we enter T_FLUSH. That way, the existing fast
459 * commits and this full commit can proceed parallely.
460 */
461 }
462 write_unlock(&journal->j_state_lock);
463
464 commit_transaction = journal->j_running_transaction;
465
466 trace_jbd2_start_commit(journal, commit_transaction);
467 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
468 commit_transaction->t_tid);
469
470 write_lock(&journal->j_state_lock);
471 journal->j_fc_off = 0;
472 J_ASSERT(commit_transaction->t_state == T_RUNNING);
473 commit_transaction->t_state = T_LOCKED;
474
475 trace_jbd2_commit_locking(journal, commit_transaction);
476 stats.run.rs_wait = commit_transaction->t_max_wait;
477 stats.run.rs_request_delay = 0;
478 stats.run.rs_locked = jiffies;
479 if (commit_transaction->t_requested)
480 stats.run.rs_request_delay =
481 jbd2_time_diff(commit_transaction->t_requested,
482 stats.run.rs_locked);
483 stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
484 stats.run.rs_locked);
485
486 // waits for any t_updates to finish
487 jbd2_journal_wait_updates(journal);
488
489 commit_transaction->t_state = T_SWITCH;
490
491 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
492 journal->j_max_transaction_buffers);
493
494 /*
495 * First thing we are allowed to do is to discard any remaining
496 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
497 * that there are no such buffers: if a large filesystem
498 * operation like a truncate needs to split itself over multiple
499 * transactions, then it may try to do a jbd2_journal_restart() while
500 * there are still BJ_Reserved buffers outstanding. These must
501 * be released cleanly from the current transaction.
502 *
503 * In this case, the filesystem must still reserve write access
504 * again before modifying the buffer in the new transaction, but
505 * we do not require it to remember exactly which old buffers it
506 * has reserved. This is consistent with the existing behaviour
507 * that multiple jbd2_journal_get_write_access() calls to the same
508 * buffer are perfectly permissible.
509 * We use journal->j_state_lock here to serialize processing of
510 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
511 */
512 while (commit_transaction->t_reserved_list) {
513 jh = commit_transaction->t_reserved_list;
514 JBUFFER_TRACE(jh, "reserved, unused: refile");
515 /*
516 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
517 * leave undo-committed data.
518 */
519 if (jh->b_committed_data) {
520 struct buffer_head *bh = jh2bh(jh);
521
522 spin_lock(&jh->b_state_lock);
523 jbd2_free(jh->b_committed_data, bh->b_size);
524 jh->b_committed_data = NULL;
525 spin_unlock(&jh->b_state_lock);
526 }
527 jbd2_journal_refile_buffer(journal, jh);
528 }
529
530 write_unlock(&journal->j_state_lock);
531 /*
532 * Now try to drop any written-back buffers from the journal's
533 * checkpoint lists. We do this *before* commit because it potentially
534 * frees some memory
535 */
536 spin_lock(&journal->j_list_lock);
537 __jbd2_journal_clean_checkpoint_list(journal, false);
538 spin_unlock(&journal->j_list_lock);
539
540 jbd2_debug(3, "JBD2: commit phase 1\n");
541
542 /*
543 * Clear revoked flag to reflect there is no revoked buffers
544 * in the next transaction which is going to be started.
545 */
546 jbd2_clear_buffer_revoked_flags(journal);
547
548 /*
549 * Switch to a new revoke table.
550 */
551 jbd2_journal_switch_revoke_table(journal);
552
553 write_lock(&journal->j_state_lock);
554 /*
555 * Reserved credits cannot be claimed anymore, free them
556 */
557 atomic_sub(atomic_read(&journal->j_reserved_credits),
558 &commit_transaction->t_outstanding_credits);
559
560 trace_jbd2_commit_flushing(journal, commit_transaction);
561 stats.run.rs_flushing = jiffies;
562 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
563 stats.run.rs_flushing);
564
565 commit_transaction->t_state = T_FLUSH;
566 journal->j_committing_transaction = commit_transaction;
567 journal->j_running_transaction = NULL;
568 start_time = ktime_get();
569 commit_transaction->t_log_start = journal->j_head;
570 wake_up_all(&journal->j_wait_transaction_locked);
571 write_unlock(&journal->j_state_lock);
572
573 jbd2_debug(3, "JBD2: commit phase 2a\n");
574
575 /*
576 * Now start flushing things to disk, in the order they appear
577 * on the transaction lists. Data blocks go first.
578 */
579 err = journal_submit_data_buffers(journal, commit_transaction);
580 if (err)
581 jbd2_journal_abort(journal, err);
582
583 blk_start_plug(&plug);
584 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
585
586 jbd2_debug(3, "JBD2: commit phase 2b\n");
587
588 /*
589 * Way to go: we have now written out all of the data for a
590 * transaction! Now comes the tricky part: we need to write out
591 * metadata. Loop over the transaction's entire buffer list:
592 */
593 write_lock(&journal->j_state_lock);
594 commit_transaction->t_state = T_COMMIT;
595 write_unlock(&journal->j_state_lock);
596
597 trace_jbd2_commit_logging(journal, commit_transaction);
598 stats.run.rs_logging = jiffies;
599 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
600 stats.run.rs_logging);
601 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
602 stats.run.rs_blocks_logged = 0;
603
604 J_ASSERT(commit_transaction->t_nr_buffers <=
605 atomic_read(&commit_transaction->t_outstanding_credits));
606
607 err = 0;
608 bufs = 0;
609 descriptor = NULL;
610 while (commit_transaction->t_buffers) {
611
612 /* Find the next buffer to be journaled... */
613
614 jh = commit_transaction->t_buffers;
615
616 /* If we're in abort mode, we just un-journal the buffer and
617 release it. */
618
619 if (is_journal_aborted(journal)) {
620 clear_buffer_jbddirty(jh2bh(jh));
621 JBUFFER_TRACE(jh, "journal is aborting: refile");
622 jbd2_buffer_abort_trigger(jh,
623 jh->b_frozen_data ?
624 jh->b_frozen_triggers :
625 jh->b_triggers);
626 jbd2_journal_refile_buffer(journal, jh);
627 /* If that was the last one, we need to clean up
628 * any descriptor buffers which may have been
629 * already allocated, even if we are now
630 * aborting. */
631 if (!commit_transaction->t_buffers)
632 goto start_journal_io;
633 continue;
634 }
635
636 /* Make sure we have a descriptor block in which to
637 record the metadata buffer. */
638
639 if (!descriptor) {
640 J_ASSERT (bufs == 0);
641
642 jbd2_debug(4, "JBD2: get descriptor\n");
643
644 descriptor = jbd2_journal_get_descriptor_buffer(
645 commit_transaction,
646 JBD2_DESCRIPTOR_BLOCK);
647 if (!descriptor) {
648 jbd2_journal_abort(journal, -EIO);
649 continue;
650 }
651
652 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
653 (unsigned long long)descriptor->b_blocknr,
654 descriptor->b_data);
655 tagp = &descriptor->b_data[sizeof(journal_header_t)];
656 space_left = descriptor->b_size -
657 sizeof(journal_header_t);
658 first_tag = 1;
659 set_buffer_jwrite(descriptor);
660 set_buffer_dirty(descriptor);
661 wbuf[bufs++] = descriptor;
662
663 /* Record it so that we can wait for IO
664 completion later */
665 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
666 jbd2_file_log_bh(&log_bufs, descriptor);
667 }
668
669 /* Where is the buffer to be written? */
670
671 err = jbd2_journal_next_log_block(journal, &blocknr);
672 /* If the block mapping failed, just abandon the buffer
673 and repeat this loop: we'll fall into the
674 refile-on-abort condition above. */
675 if (err) {
676 jbd2_journal_abort(journal, err);
677 continue;
678 }
679
680 /*
681 * start_this_handle() uses t_outstanding_credits to determine
682 * the free space in the log.
683 */
684 atomic_dec(&commit_transaction->t_outstanding_credits);
685
686 /* Bump b_count to prevent truncate from stumbling over
687 the shadowed buffer! @@@ This can go if we ever get
688 rid of the shadow pairing of buffers. */
689 atomic_inc(&jh2bh(jh)->b_count);
690
691 /*
692 * Make a temporary IO buffer with which to write it out
693 * (this will requeue the metadata buffer to BJ_Shadow).
694 */
695 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
696 JBUFFER_TRACE(jh, "ph3: write metadata");
697 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
698 jh, &wbuf[bufs], blocknr);
699 if (flags < 0) {
700 jbd2_journal_abort(journal, flags);
701 continue;
702 }
703 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
704
705 /* Record the new block's tag in the current descriptor
706 buffer */
707
708 tag_flag = 0;
709 if (flags & 1)
710 tag_flag |= JBD2_FLAG_ESCAPE;
711 if (!first_tag)
712 tag_flag |= JBD2_FLAG_SAME_UUID;
713
714 tag = (journal_block_tag_t *) tagp;
715 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
716 tag->t_flags = cpu_to_be16(tag_flag);
717 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
718 commit_transaction->t_tid);
719 tagp += tag_bytes;
720 space_left -= tag_bytes;
721 bufs++;
722
723 if (first_tag) {
724 memcpy (tagp, journal->j_uuid, 16);
725 tagp += 16;
726 space_left -= 16;
727 first_tag = 0;
728 }
729
730 /* If there's no more to do, or if the descriptor is full,
731 let the IO rip! */
732
733 if (bufs == journal->j_wbufsize ||
734 commit_transaction->t_buffers == NULL ||
735 space_left < tag_bytes + 16 + csum_size) {
736
737 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
738
739 /* Write an end-of-descriptor marker before
740 submitting the IOs. "tag" still points to
741 the last tag we set up. */
742
743 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
744start_journal_io:
745 if (descriptor)
746 jbd2_descriptor_block_csum_set(journal,
747 descriptor);
748
749 for (i = 0; i < bufs; i++) {
750 struct buffer_head *bh = wbuf[i];
751 /*
752 * Compute checksum.
753 */
754 if (jbd2_has_feature_checksum(journal)) {
755 crc32_sum =
756 jbd2_checksum_data(crc32_sum, bh);
757 }
758
759 lock_buffer(bh);
760 clear_buffer_dirty(bh);
761 set_buffer_uptodate(bh);
762 bh->b_end_io = journal_end_buffer_io_sync;
763 submit_bh(REQ_OP_WRITE | REQ_SYNC, bh);
764 }
765 cond_resched();
766
767 /* Force a new descriptor to be generated next
768 time round the loop. */
769 descriptor = NULL;
770 bufs = 0;
771 }
772 }
773
774 err = journal_finish_inode_data_buffers(journal, commit_transaction);
775 if (err) {
776 printk(KERN_WARNING
777 "JBD2: Detected IO errors while flushing file data "
778 "on %s\n", journal->j_devname);
779 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
780 jbd2_journal_abort(journal, err);
781 err = 0;
782 }
783
784 /*
785 * Get current oldest transaction in the log before we issue flush
786 * to the filesystem device. After the flush we can be sure that
787 * blocks of all older transactions are checkpointed to persistent
788 * storage and we will be safe to update journal start in the
789 * superblock with the numbers we get here.
790 */
791 update_tail =
792 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
793
794 write_lock(&journal->j_state_lock);
795 if (update_tail) {
796 long freed = first_block - journal->j_tail;
797
798 if (first_block < journal->j_tail)
799 freed += journal->j_last - journal->j_first;
800 /* Update tail only if we free significant amount of space */
801 if (freed < jbd2_journal_get_max_txn_bufs(journal))
802 update_tail = 0;
803 }
804 J_ASSERT(commit_transaction->t_state == T_COMMIT);
805 commit_transaction->t_state = T_COMMIT_DFLUSH;
806 write_unlock(&journal->j_state_lock);
807
808 /*
809 * If the journal is not located on the file system device,
810 * then we must flush the file system device before we issue
811 * the commit record
812 */
813 if (commit_transaction->t_need_data_flush &&
814 (journal->j_fs_dev != journal->j_dev) &&
815 (journal->j_flags & JBD2_BARRIER))
816 blkdev_issue_flush(journal->j_fs_dev);
817
818 /* Done it all: now write the commit record asynchronously. */
819 if (jbd2_has_feature_async_commit(journal)) {
820 err = journal_submit_commit_record(journal, commit_transaction,
821 &cbh, crc32_sum);
822 if (err)
823 jbd2_journal_abort(journal, err);
824 }
825
826 blk_finish_plug(&plug);
827
828 /* Lo and behold: we have just managed to send a transaction to
829 the log. Before we can commit it, wait for the IO so far to
830 complete. Control buffers being written are on the
831 transaction's t_log_list queue, and metadata buffers are on
832 the io_bufs list.
833
834 Wait for the buffers in reverse order. That way we are
835 less likely to be woken up until all IOs have completed, and
836 so we incur less scheduling load.
837 */
838
839 jbd2_debug(3, "JBD2: commit phase 3\n");
840
841 while (!list_empty(&io_bufs)) {
842 struct buffer_head *bh = list_entry(io_bufs.prev,
843 struct buffer_head,
844 b_assoc_buffers);
845
846 wait_on_buffer(bh);
847 cond_resched();
848
849 if (unlikely(!buffer_uptodate(bh)))
850 err = -EIO;
851 jbd2_unfile_log_bh(bh);
852 stats.run.rs_blocks_logged++;
853
854 /*
855 * The list contains temporary buffer heads created by
856 * jbd2_journal_write_metadata_buffer().
857 */
858 BUFFER_TRACE(bh, "dumping temporary bh");
859 __brelse(bh);
860 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
861 free_buffer_head(bh);
862
863 /* We also have to refile the corresponding shadowed buffer */
864 jh = commit_transaction->t_shadow_list->b_tprev;
865 bh = jh2bh(jh);
866 clear_buffer_jwrite(bh);
867 J_ASSERT_BH(bh, buffer_jbddirty(bh));
868 J_ASSERT_BH(bh, !buffer_shadow(bh));
869
870 /* The metadata is now released for reuse, but we need
871 to remember it against this transaction so that when
872 we finally commit, we can do any checkpointing
873 required. */
874 JBUFFER_TRACE(jh, "file as BJ_Forget");
875 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
876 JBUFFER_TRACE(jh, "brelse shadowed buffer");
877 __brelse(bh);
878 }
879
880 J_ASSERT (commit_transaction->t_shadow_list == NULL);
881
882 jbd2_debug(3, "JBD2: commit phase 4\n");
883
884 /* Here we wait for the revoke record and descriptor record buffers */
885 while (!list_empty(&log_bufs)) {
886 struct buffer_head *bh;
887
888 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
889 wait_on_buffer(bh);
890 cond_resched();
891
892 if (unlikely(!buffer_uptodate(bh)))
893 err = -EIO;
894
895 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
896 clear_buffer_jwrite(bh);
897 jbd2_unfile_log_bh(bh);
898 stats.run.rs_blocks_logged++;
899 __brelse(bh); /* One for getblk */
900 /* AKPM: bforget here */
901 }
902
903 if (err)
904 jbd2_journal_abort(journal, err);
905
906 jbd2_debug(3, "JBD2: commit phase 5\n");
907 write_lock(&journal->j_state_lock);
908 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
909 commit_transaction->t_state = T_COMMIT_JFLUSH;
910 write_unlock(&journal->j_state_lock);
911
912 if (!jbd2_has_feature_async_commit(journal)) {
913 err = journal_submit_commit_record(journal, commit_transaction,
914 &cbh, crc32_sum);
915 if (err)
916 jbd2_journal_abort(journal, err);
917 }
918 if (cbh)
919 err = journal_wait_on_commit_record(journal, cbh);
920 stats.run.rs_blocks_logged++;
921 if (jbd2_has_feature_async_commit(journal) &&
922 journal->j_flags & JBD2_BARRIER) {
923 blkdev_issue_flush(journal->j_dev);
924 }
925
926 if (err)
927 jbd2_journal_abort(journal, err);
928
929 WARN_ON_ONCE(
930 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
931
932 /*
933 * Now disk caches for filesystem device are flushed so we are safe to
934 * erase checkpointed transactions from the log by updating journal
935 * superblock.
936 */
937 if (update_tail)
938 jbd2_update_log_tail(journal, first_tid, first_block);
939
940 /* End of a transaction! Finally, we can do checkpoint
941 processing: any buffers committed as a result of this
942 transaction can be removed from any checkpoint list it was on
943 before. */
944
945 jbd2_debug(3, "JBD2: commit phase 6\n");
946
947 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
948 J_ASSERT(commit_transaction->t_buffers == NULL);
949 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
950 J_ASSERT(commit_transaction->t_shadow_list == NULL);
951
952restart_loop:
953 /*
954 * As there are other places (journal_unmap_buffer()) adding buffers
955 * to this list we have to be careful and hold the j_list_lock.
956 */
957 spin_lock(&journal->j_list_lock);
958 while (commit_transaction->t_forget) {
959 transaction_t *cp_transaction;
960 struct buffer_head *bh;
961 int try_to_free = 0;
962 bool drop_ref;
963
964 jh = commit_transaction->t_forget;
965 spin_unlock(&journal->j_list_lock);
966 bh = jh2bh(jh);
967 /*
968 * Get a reference so that bh cannot be freed before we are
969 * done with it.
970 */
971 get_bh(bh);
972 spin_lock(&jh->b_state_lock);
973 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
974
975 /*
976 * If there is undo-protected committed data against
977 * this buffer, then we can remove it now. If it is a
978 * buffer needing such protection, the old frozen_data
979 * field now points to a committed version of the
980 * buffer, so rotate that field to the new committed
981 * data.
982 *
983 * Otherwise, we can just throw away the frozen data now.
984 *
985 * We also know that the frozen data has already fired
986 * its triggers if they exist, so we can clear that too.
987 */
988 if (jh->b_committed_data) {
989 jbd2_free(jh->b_committed_data, bh->b_size);
990 jh->b_committed_data = NULL;
991 if (jh->b_frozen_data) {
992 jh->b_committed_data = jh->b_frozen_data;
993 jh->b_frozen_data = NULL;
994 jh->b_frozen_triggers = NULL;
995 }
996 } else if (jh->b_frozen_data) {
997 jbd2_free(jh->b_frozen_data, bh->b_size);
998 jh->b_frozen_data = NULL;
999 jh->b_frozen_triggers = NULL;
1000 }
1001
1002 spin_lock(&journal->j_list_lock);
1003 cp_transaction = jh->b_cp_transaction;
1004 if (cp_transaction) {
1005 JBUFFER_TRACE(jh, "remove from old cp transaction");
1006 cp_transaction->t_chp_stats.cs_dropped++;
1007 __jbd2_journal_remove_checkpoint(jh);
1008 }
1009
1010 /* Only re-checkpoint the buffer_head if it is marked
1011 * dirty. If the buffer was added to the BJ_Forget list
1012 * by jbd2_journal_forget, it may no longer be dirty and
1013 * there's no point in keeping a checkpoint record for
1014 * it. */
1015
1016 /*
1017 * A buffer which has been freed while still being journaled
1018 * by a previous transaction, refile the buffer to BJ_Forget of
1019 * the running transaction. If the just committed transaction
1020 * contains "add to orphan" operation, we can completely
1021 * invalidate the buffer now. We are rather through in that
1022 * since the buffer may be still accessible when blocksize <
1023 * pagesize and it is attached to the last partial page.
1024 */
1025 if (buffer_freed(bh) && !jh->b_next_transaction) {
1026 struct address_space *mapping;
1027
1028 clear_buffer_freed(bh);
1029 clear_buffer_jbddirty(bh);
1030
1031 /*
1032 * Block device buffers need to stay mapped all the
1033 * time, so it is enough to clear buffer_jbddirty and
1034 * buffer_freed bits. For the file mapping buffers (i.e.
1035 * journalled data) we need to unmap buffer and clear
1036 * more bits. We also need to be careful about the check
1037 * because the data page mapping can get cleared under
1038 * our hands. Note that if mapping == NULL, we don't
1039 * need to make buffer unmapped because the page is
1040 * already detached from the mapping and buffers cannot
1041 * get reused.
1042 */
1043 mapping = READ_ONCE(bh->b_page->mapping);
1044 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1045 clear_buffer_mapped(bh);
1046 clear_buffer_new(bh);
1047 clear_buffer_req(bh);
1048 bh->b_bdev = NULL;
1049 }
1050 }
1051
1052 if (buffer_jbddirty(bh)) {
1053 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1054 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1055 if (is_journal_aborted(journal))
1056 clear_buffer_jbddirty(bh);
1057 } else {
1058 J_ASSERT_BH(bh, !buffer_dirty(bh));
1059 /*
1060 * The buffer on BJ_Forget list and not jbddirty means
1061 * it has been freed by this transaction and hence it
1062 * could not have been reallocated until this
1063 * transaction has committed. *BUT* it could be
1064 * reallocated once we have written all the data to
1065 * disk and before we process the buffer on BJ_Forget
1066 * list.
1067 */
1068 if (!jh->b_next_transaction)
1069 try_to_free = 1;
1070 }
1071 JBUFFER_TRACE(jh, "refile or unfile buffer");
1072 drop_ref = __jbd2_journal_refile_buffer(jh);
1073 spin_unlock(&jh->b_state_lock);
1074 if (drop_ref)
1075 jbd2_journal_put_journal_head(jh);
1076 if (try_to_free)
1077 release_buffer_page(bh); /* Drops bh reference */
1078 else
1079 __brelse(bh);
1080 cond_resched_lock(&journal->j_list_lock);
1081 }
1082 spin_unlock(&journal->j_list_lock);
1083 /*
1084 * This is a bit sleazy. We use j_list_lock to protect transition
1085 * of a transaction into T_FINISHED state and calling
1086 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1087 * other checkpointing code processing the transaction...
1088 */
1089 write_lock(&journal->j_state_lock);
1090 spin_lock(&journal->j_list_lock);
1091 /*
1092 * Now recheck if some buffers did not get attached to the transaction
1093 * while the lock was dropped...
1094 */
1095 if (commit_transaction->t_forget) {
1096 spin_unlock(&journal->j_list_lock);
1097 write_unlock(&journal->j_state_lock);
1098 goto restart_loop;
1099 }
1100
1101 /* Add the transaction to the checkpoint list
1102 * __journal_remove_checkpoint() can not destroy transaction
1103 * under us because it is not marked as T_FINISHED yet */
1104 if (journal->j_checkpoint_transactions == NULL) {
1105 journal->j_checkpoint_transactions = commit_transaction;
1106 commit_transaction->t_cpnext = commit_transaction;
1107 commit_transaction->t_cpprev = commit_transaction;
1108 } else {
1109 commit_transaction->t_cpnext =
1110 journal->j_checkpoint_transactions;
1111 commit_transaction->t_cpprev =
1112 commit_transaction->t_cpnext->t_cpprev;
1113 commit_transaction->t_cpnext->t_cpprev =
1114 commit_transaction;
1115 commit_transaction->t_cpprev->t_cpnext =
1116 commit_transaction;
1117 }
1118 spin_unlock(&journal->j_list_lock);
1119
1120 /* Done with this transaction! */
1121
1122 jbd2_debug(3, "JBD2: commit phase 7\n");
1123
1124 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1125
1126 commit_transaction->t_start = jiffies;
1127 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1128 commit_transaction->t_start);
1129
1130 /*
1131 * File the transaction statistics
1132 */
1133 stats.ts_tid = commit_transaction->t_tid;
1134 stats.run.rs_handle_count =
1135 atomic_read(&commit_transaction->t_handle_count);
1136 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1137 commit_transaction->t_tid, &stats.run);
1138 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1139
1140 commit_transaction->t_state = T_COMMIT_CALLBACK;
1141 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1142 journal->j_commit_sequence = commit_transaction->t_tid;
1143 journal->j_committing_transaction = NULL;
1144 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1145
1146 /*
1147 * weight the commit time higher than the average time so we don't
1148 * react too strongly to vast changes in the commit time
1149 */
1150 if (likely(journal->j_average_commit_time))
1151 journal->j_average_commit_time = (commit_time +
1152 journal->j_average_commit_time*3) / 4;
1153 else
1154 journal->j_average_commit_time = commit_time;
1155
1156 write_unlock(&journal->j_state_lock);
1157
1158 if (journal->j_commit_callback)
1159 journal->j_commit_callback(journal, commit_transaction);
1160 if (journal->j_fc_cleanup_callback)
1161 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1162
1163 trace_jbd2_end_commit(journal, commit_transaction);
1164 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1165 journal->j_commit_sequence, journal->j_tail_sequence);
1166
1167 write_lock(&journal->j_state_lock);
1168 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1169 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1170 spin_lock(&journal->j_list_lock);
1171 commit_transaction->t_state = T_FINISHED;
1172 /* Check if the transaction can be dropped now that we are finished */
1173 if (commit_transaction->t_checkpoint_list == NULL &&
1174 commit_transaction->t_checkpoint_io_list == NULL) {
1175 __jbd2_journal_drop_transaction(journal, commit_transaction);
1176 jbd2_journal_free_transaction(commit_transaction);
1177 }
1178 spin_unlock(&journal->j_list_lock);
1179 write_unlock(&journal->j_state_lock);
1180 wake_up(&journal->j_wait_done_commit);
1181 wake_up(&journal->j_fc_wait);
1182
1183 /*
1184 * Calculate overall stats
1185 */
1186 spin_lock(&journal->j_history_lock);
1187 journal->j_stats.ts_tid++;
1188 journal->j_stats.ts_requested += stats.ts_requested;
1189 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1190 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1191 journal->j_stats.run.rs_running += stats.run.rs_running;
1192 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1193 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1194 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1195 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1196 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1197 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1198 spin_unlock(&journal->j_history_lock);
1199}
1// SPDX-License-Identifier: GPL-2.0+
2/*
3 * linux/fs/jbd2/commit.c
4 *
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
6 *
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
8 *
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
11 */
12
13#include <linux/time.h>
14#include <linux/fs.h>
15#include <linux/jbd2.h>
16#include <linux/errno.h>
17#include <linux/slab.h>
18#include <linux/mm.h>
19#include <linux/pagemap.h>
20#include <linux/jiffies.h>
21#include <linux/crc32.h>
22#include <linux/writeback.h>
23#include <linux/backing-dev.h>
24#include <linux/bio.h>
25#include <linux/blkdev.h>
26#include <linux/bitops.h>
27#include <trace/events/jbd2.h>
28
29/*
30 * IO end handler for temporary buffer_heads handling writes to the journal.
31 */
32static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
33{
34 struct buffer_head *orig_bh = bh->b_private;
35
36 BUFFER_TRACE(bh, "");
37 if (uptodate)
38 set_buffer_uptodate(bh);
39 else
40 clear_buffer_uptodate(bh);
41 if (orig_bh) {
42 clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
43 smp_mb__after_atomic();
44 wake_up_bit(&orig_bh->b_state, BH_Shadow);
45 }
46 unlock_buffer(bh);
47}
48
49/*
50 * When an ext4 file is truncated, it is possible that some pages are not
51 * successfully freed, because they are attached to a committing transaction.
52 * After the transaction commits, these pages are left on the LRU, with no
53 * ->mapping, and with attached buffers. These pages are trivially reclaimable
54 * by the VM, but their apparent absence upsets the VM accounting, and it makes
55 * the numbers in /proc/meminfo look odd.
56 *
57 * So here, we have a buffer which has just come off the forget list. Look to
58 * see if we can strip all buffers from the backing page.
59 *
60 * Called under lock_journal(), and possibly under journal_datalist_lock. The
61 * caller provided us with a ref against the buffer, and we drop that here.
62 */
63static void release_buffer_page(struct buffer_head *bh)
64{
65 struct page *page;
66
67 if (buffer_dirty(bh))
68 goto nope;
69 if (atomic_read(&bh->b_count) != 1)
70 goto nope;
71 page = bh->b_page;
72 if (!page)
73 goto nope;
74 if (page->mapping)
75 goto nope;
76
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
79 goto nope;
80
81 get_page(page);
82 __brelse(bh);
83 try_to_free_buffers(page);
84 unlock_page(page);
85 put_page(page);
86 return;
87
88nope:
89 __brelse(bh);
90}
91
92static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
93{
94 struct commit_header *h;
95 __u32 csum;
96
97 if (!jbd2_journal_has_csum_v2or3(j))
98 return;
99
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 0;
103 h->h_chksum[0] = 0;
104 csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
105 h->h_chksum[0] = cpu_to_be32(csum);
106}
107
108/*
109 * Done it all: now submit the commit record. We should have
110 * cleaned up our previous buffers by now, so if we are in abort
111 * mode we can now just skip the rest of the journal write
112 * entirely.
113 *
114 * Returns 1 if the journal needs to be aborted or 0 on success
115 */
116static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
119 __u32 crc32_sum)
120{
121 struct commit_header *tmp;
122 struct buffer_head *bh;
123 int ret;
124 struct timespec64 now;
125
126 *cbh = NULL;
127
128 if (is_journal_aborted(journal))
129 return 0;
130
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
132 JBD2_COMMIT_BLOCK);
133 if (!bh)
134 return 1;
135
136 tmp = (struct commit_header *)bh->b_data;
137 ktime_get_coarse_real_ts64(&now);
138 tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
139 tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
140
141 if (jbd2_has_feature_checksum(journal)) {
142 tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
143 tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
144 tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
145 }
146 jbd2_commit_block_csum_set(journal, bh);
147
148 BUFFER_TRACE(bh, "submit commit block");
149 lock_buffer(bh);
150 clear_buffer_dirty(bh);
151 set_buffer_uptodate(bh);
152 bh->b_end_io = journal_end_buffer_io_sync;
153
154 if (journal->j_flags & JBD2_BARRIER &&
155 !jbd2_has_feature_async_commit(journal))
156 ret = submit_bh(REQ_OP_WRITE,
157 REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh);
158 else
159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
160
161 *cbh = bh;
162 return ret;
163}
164
165/*
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
168 */
169static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
171{
172 int ret = 0;
173
174 clear_buffer_dirty(bh);
175 wait_on_buffer(bh);
176
177 if (unlikely(!buffer_uptodate(bh)))
178 ret = -EIO;
179 put_bh(bh); /* One for getblk() */
180
181 return ret;
182}
183
184/*
185 * write the filemap data using writepage() address_space_operations.
186 * We don't do block allocation here even for delalloc. We don't
187 * use writepages() because with delayed allocation we may be doing
188 * block allocation in writepages().
189 */
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}