1 // SPDX-License-Identifier: GPL-2.0+
3 * linux/fs/jbd2/commit.c
5 * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
7 * Copyright 1998 Red Hat corp --- All Rights Reserved
9 * Journal commit routines for the generic filesystem journaling code;
10 * part of the ext2fs journaling system.
13 #include <linux/time.h>
15 #include <linux/jbd2.h>
16 #include <linux/errno.h>
17 #include <linux/slab.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>
30 * IO end handler for temporary buffer_heads handling writes to the journal.
32 static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
34 struct buffer_head *orig_bh = bh->b_private;
38 set_buffer_uptodate(bh);
40 clear_buffer_uptodate(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);
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.
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.
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.
63 static void release_buffer_page(struct buffer_head *bh)
70 if (atomic_read(&bh->b_count) != 1)
75 folio = page_folio(page);
79 /* OK, it's a truncated page */
80 if (!folio_trylock(folio))
85 try_to_free_buffers(folio);
94 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
96 struct commit_header *h;
99 if (!jbd2_journal_has_csum_v2or3(j))
102 h = (struct commit_header *)(bh->b_data);
103 h->h_chksum_type = 0;
104 h->h_chksum_size = 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);
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
116 * Returns 1 if the journal needs to be aborted or 0 on success
118 static int journal_submit_commit_record(journal_t *journal,
119 transaction_t *commit_transaction,
120 struct buffer_head **cbh,
123 struct commit_header *tmp;
124 struct buffer_head *bh;
125 struct timespec64 now;
126 blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
130 if (is_journal_aborted(journal))
133 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
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);
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);
148 jbd2_commit_block_csum_set(journal, bh);
150 BUFFER_TRACE(bh, "submit commit block");
152 clear_buffer_dirty(bh);
153 set_buffer_uptodate(bh);
154 bh->b_end_io = journal_end_buffer_io_sync;
156 if (journal->j_flags & JBD2_BARRIER &&
157 !jbd2_has_feature_async_commit(journal))
158 write_flags |= REQ_PREFLUSH | REQ_FUA;
160 submit_bh(write_flags, bh);
166 * This function along with journal_submit_commit_record
167 * allows to write the commit record asynchronously.
169 static int journal_wait_on_commit_record(journal_t *journal,
170 struct buffer_head *bh)
174 clear_buffer_dirty(bh);
177 if (unlikely(!buffer_uptodate(bh)))
179 put_bh(bh); /* One for getblk() */
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().
190 int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode)
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,
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.
206 return generic_writepages(mapping, &wbc);
209 /* Send all the data buffers related to an inode */
210 int jbd2_submit_inode_data(struct jbd2_inode *jinode)
213 if (!jinode || !(jinode->i_flags & JI_WRITE_DATA))
216 trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
217 return jbd2_journal_submit_inode_data_buffers(jinode);
220 EXPORT_SYMBOL(jbd2_submit_inode_data);
222 int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
224 if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) ||
225 !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping)
227 return filemap_fdatawait_range_keep_errors(
228 jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start,
229 jinode->i_dirty_end);
231 EXPORT_SYMBOL(jbd2_wait_inode_data);
234 * Submit all the data buffers of inode associated with the transaction to
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.
241 static int journal_submit_data_buffers(journal_t *journal,
242 transaction_t *commit_transaction)
244 struct jbd2_inode *jinode;
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))
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);
260 spin_lock(&journal->j_list_lock);
261 J_ASSERT(jinode->i_transaction == commit_transaction);
262 jinode->i_flags &= ~JI_COMMIT_RUNNING;
264 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
266 spin_unlock(&journal->j_list_lock);
270 int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
272 struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
274 return filemap_fdatawait_range_keep_errors(mapping,
275 jinode->i_dirty_start,
276 jinode->i_dirty_end);
280 * Wait for data submitted for writeout, refile inodes to proper
281 * transaction if needed.
284 static int journal_finish_inode_data_buffers(journal_t *journal,
285 transaction_t *commit_transaction)
287 struct jbd2_inode *jinode, *next_i;
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))
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);
304 spin_lock(&journal->j_list_lock);
305 jinode->i_flags &= ~JI_COMMIT_RUNNING;
307 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
310 /* Now refile inode to proper lists */
311 list_for_each_entry_safe(jinode, next_i,
312 &commit_transaction->t_inode_list, i_list) {
313 list_del(&jinode->i_list);
314 if (jinode->i_next_transaction) {
315 jinode->i_transaction = jinode->i_next_transaction;
316 jinode->i_next_transaction = NULL;
317 list_add(&jinode->i_list,
318 &jinode->i_transaction->t_inode_list);
320 jinode->i_transaction = NULL;
321 jinode->i_dirty_start = 0;
322 jinode->i_dirty_end = 0;
325 spin_unlock(&journal->j_list_lock);
330 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
332 struct page *page = bh->b_page;
336 addr = kmap_atomic(page);
337 checksum = crc32_be(crc32_sum,
338 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
344 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
345 unsigned long long block)
347 tag->t_blocknr = cpu_to_be32(block & (u32)~0);
348 if (jbd2_has_feature_64bit(j))
349 tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
352 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
353 struct buffer_head *bh, __u32 sequence)
355 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
356 struct page *page = bh->b_page;
361 if (!jbd2_journal_has_csum_v2or3(j))
364 seq = cpu_to_be32(sequence);
365 addr = kmap_atomic(page);
366 csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
367 csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
371 if (jbd2_has_feature_csum3(j))
372 tag3->t_checksum = cpu_to_be32(csum32);
374 tag->t_checksum = cpu_to_be16(csum32);
377 * jbd2_journal_commit_transaction
379 * The primary function for committing a transaction to the log. This
380 * function is called by the journal thread to begin a complete commit.
382 void jbd2_journal_commit_transaction(journal_t *journal)
384 struct transaction_stats_s stats;
385 transaction_t *commit_transaction;
386 struct journal_head *jh;
387 struct buffer_head *descriptor;
388 struct buffer_head **wbuf = journal->j_wbuf;
392 unsigned long long blocknr;
396 journal_block_tag_t *tag = NULL;
401 int tag_bytes = journal_tag_bytes(journal);
402 struct buffer_head *cbh = NULL; /* For transactional checksums */
403 __u32 crc32_sum = ~0;
404 struct blk_plug plug;
405 /* Tail of the journal */
406 unsigned long first_block;
413 if (jbd2_journal_has_csum_v2or3(journal))
414 csum_size = sizeof(struct jbd2_journal_block_tail);
417 * First job: lock down the current transaction and wait for
418 * all outstanding updates to complete.
421 /* Do we need to erase the effects of a prior jbd2_journal_flush? */
422 if (journal->j_flags & JBD2_FLUSHED) {
423 jbd2_debug(3, "super block updated\n");
424 mutex_lock_io(&journal->j_checkpoint_mutex);
426 * We hold j_checkpoint_mutex so tail cannot change under us.
427 * We don't need any special data guarantees for writing sb
428 * since journal is empty and it is ok for write to be
429 * flushed only with transaction commit.
431 jbd2_journal_update_sb_log_tail(journal,
432 journal->j_tail_sequence,
434 mutex_unlock(&journal->j_checkpoint_mutex);
436 jbd2_debug(3, "superblock not updated\n");
439 J_ASSERT(journal->j_running_transaction != NULL);
440 J_ASSERT(journal->j_committing_transaction == NULL);
442 write_lock(&journal->j_state_lock);
443 journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
444 while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
447 prepare_to_wait(&journal->j_fc_wait, &wait,
448 TASK_UNINTERRUPTIBLE);
449 write_unlock(&journal->j_state_lock);
451 write_lock(&journal->j_state_lock);
452 finish_wait(&journal->j_fc_wait, &wait);
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.
463 write_unlock(&journal->j_state_lock);
465 commit_transaction = journal->j_running_transaction;
467 trace_jbd2_start_commit(journal, commit_transaction);
468 jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
469 commit_transaction->t_tid);
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;
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);
487 // waits for any t_updates to finish
488 jbd2_journal_wait_updates(journal);
490 commit_transaction->t_state = T_SWITCH;
492 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
493 journal->j_max_transaction_buffers);
496 * First thing we are allowed to do is to discard any remaining
497 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
498 * that there are no such buffers: if a large filesystem
499 * operation like a truncate needs to split itself over multiple
500 * transactions, then it may try to do a jbd2_journal_restart() while
501 * there are still BJ_Reserved buffers outstanding. These must
502 * be released cleanly from the current transaction.
504 * In this case, the filesystem must still reserve write access
505 * again before modifying the buffer in the new transaction, but
506 * we do not require it to remember exactly which old buffers it
507 * has reserved. This is consistent with the existing behaviour
508 * that multiple jbd2_journal_get_write_access() calls to the same
509 * buffer are perfectly permissible.
510 * We use journal->j_state_lock here to serialize processing of
511 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
513 while (commit_transaction->t_reserved_list) {
514 jh = commit_transaction->t_reserved_list;
515 JBUFFER_TRACE(jh, "reserved, unused: refile");
517 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
518 * leave undo-committed data.
520 if (jh->b_committed_data) {
521 struct buffer_head *bh = jh2bh(jh);
523 spin_lock(&jh->b_state_lock);
524 jbd2_free(jh->b_committed_data, bh->b_size);
525 jh->b_committed_data = NULL;
526 spin_unlock(&jh->b_state_lock);
528 jbd2_journal_refile_buffer(journal, jh);
531 write_unlock(&journal->j_state_lock);
533 * Now try to drop any written-back buffers from the journal's
534 * checkpoint lists. We do this *before* commit because it potentially
537 spin_lock(&journal->j_list_lock);
538 __jbd2_journal_clean_checkpoint_list(journal, false);
539 spin_unlock(&journal->j_list_lock);
541 jbd2_debug(3, "JBD2: commit phase 1\n");
544 * Clear revoked flag to reflect there is no revoked buffers
545 * in the next transaction which is going to be started.
547 jbd2_clear_buffer_revoked_flags(journal);
550 * Switch to a new revoke table.
552 jbd2_journal_switch_revoke_table(journal);
554 write_lock(&journal->j_state_lock);
556 * Reserved credits cannot be claimed anymore, free them
558 atomic_sub(atomic_read(&journal->j_reserved_credits),
559 &commit_transaction->t_outstanding_credits);
561 trace_jbd2_commit_flushing(journal, commit_transaction);
562 stats.run.rs_flushing = jiffies;
563 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
564 stats.run.rs_flushing);
566 commit_transaction->t_state = T_FLUSH;
567 journal->j_committing_transaction = commit_transaction;
568 journal->j_running_transaction = NULL;
569 start_time = ktime_get();
570 commit_transaction->t_log_start = journal->j_head;
571 wake_up_all(&journal->j_wait_transaction_locked);
572 write_unlock(&journal->j_state_lock);
574 jbd2_debug(3, "JBD2: commit phase 2a\n");
577 * Now start flushing things to disk, in the order they appear
578 * on the transaction lists. Data blocks go first.
580 err = journal_submit_data_buffers(journal, commit_transaction);
582 jbd2_journal_abort(journal, err);
584 blk_start_plug(&plug);
585 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
587 jbd2_debug(3, "JBD2: commit phase 2b\n");
590 * Way to go: we have now written out all of the data for a
591 * transaction! Now comes the tricky part: we need to write out
592 * metadata. Loop over the transaction's entire buffer list:
594 write_lock(&journal->j_state_lock);
595 commit_transaction->t_state = T_COMMIT;
596 write_unlock(&journal->j_state_lock);
598 trace_jbd2_commit_logging(journal, commit_transaction);
599 stats.run.rs_logging = jiffies;
600 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
601 stats.run.rs_logging);
602 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
603 stats.run.rs_blocks_logged = 0;
605 J_ASSERT(commit_transaction->t_nr_buffers <=
606 atomic_read(&commit_transaction->t_outstanding_credits));
611 while (commit_transaction->t_buffers) {
613 /* Find the next buffer to be journaled... */
615 jh = commit_transaction->t_buffers;
617 /* If we're in abort mode, we just un-journal the buffer and
620 if (is_journal_aborted(journal)) {
621 clear_buffer_jbddirty(jh2bh(jh));
622 JBUFFER_TRACE(jh, "journal is aborting: refile");
623 jbd2_buffer_abort_trigger(jh,
625 jh->b_frozen_triggers :
627 jbd2_journal_refile_buffer(journal, jh);
628 /* If that was the last one, we need to clean up
629 * any descriptor buffers which may have been
630 * already allocated, even if we are now
632 if (!commit_transaction->t_buffers)
633 goto start_journal_io;
637 /* Make sure we have a descriptor block in which to
638 record the metadata buffer. */
641 J_ASSERT (bufs == 0);
643 jbd2_debug(4, "JBD2: get descriptor\n");
645 descriptor = jbd2_journal_get_descriptor_buffer(
647 JBD2_DESCRIPTOR_BLOCK);
649 jbd2_journal_abort(journal, -EIO);
653 jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
654 (unsigned long long)descriptor->b_blocknr,
656 tagp = &descriptor->b_data[sizeof(journal_header_t)];
657 space_left = descriptor->b_size -
658 sizeof(journal_header_t);
660 set_buffer_jwrite(descriptor);
661 set_buffer_dirty(descriptor);
662 wbuf[bufs++] = descriptor;
664 /* Record it so that we can wait for IO
666 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
667 jbd2_file_log_bh(&log_bufs, descriptor);
670 /* Where is the buffer to be written? */
672 err = jbd2_journal_next_log_block(journal, &blocknr);
673 /* If the block mapping failed, just abandon the buffer
674 and repeat this loop: we'll fall into the
675 refile-on-abort condition above. */
677 jbd2_journal_abort(journal, err);
682 * start_this_handle() uses t_outstanding_credits to determine
683 * the free space in the log.
685 atomic_dec(&commit_transaction->t_outstanding_credits);
687 /* Bump b_count to prevent truncate from stumbling over
688 the shadowed buffer! @@@ This can go if we ever get
689 rid of the shadow pairing of buffers. */
690 atomic_inc(&jh2bh(jh)->b_count);
693 * Make a temporary IO buffer with which to write it out
694 * (this will requeue the metadata buffer to BJ_Shadow).
696 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
697 JBUFFER_TRACE(jh, "ph3: write metadata");
698 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
699 jh, &wbuf[bufs], blocknr);
701 jbd2_journal_abort(journal, flags);
704 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
706 /* Record the new block's tag in the current descriptor
711 tag_flag |= JBD2_FLAG_ESCAPE;
713 tag_flag |= JBD2_FLAG_SAME_UUID;
715 tag = (journal_block_tag_t *) tagp;
716 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
717 tag->t_flags = cpu_to_be16(tag_flag);
718 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
719 commit_transaction->t_tid);
721 space_left -= tag_bytes;
725 memcpy (tagp, journal->j_uuid, 16);
731 /* If there's no more to do, or if the descriptor is full,
734 if (bufs == journal->j_wbufsize ||
735 commit_transaction->t_buffers == NULL ||
736 space_left < tag_bytes + 16 + csum_size) {
738 jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
740 /* Write an end-of-descriptor marker before
741 submitting the IOs. "tag" still points to
742 the last tag we set up. */
744 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
747 jbd2_descriptor_block_csum_set(journal,
750 for (i = 0; i < bufs; i++) {
751 struct buffer_head *bh = wbuf[i];
756 if (jbd2_has_feature_checksum(journal)) {
758 jbd2_checksum_data(crc32_sum, bh);
762 clear_buffer_dirty(bh);
763 set_buffer_uptodate(bh);
764 bh->b_end_io = journal_end_buffer_io_sync;
765 submit_bh(REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
770 /* Force a new descriptor to be generated next
771 time round the loop. */
777 err = journal_finish_inode_data_buffers(journal, commit_transaction);
780 "JBD2: Detected IO errors while flushing file data "
781 "on %s\n", journal->j_devname);
782 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
783 jbd2_journal_abort(journal, err);
788 * Get current oldest transaction in the log before we issue flush
789 * to the filesystem device. After the flush we can be sure that
790 * blocks of all older transactions are checkpointed to persistent
791 * storage and we will be safe to update journal start in the
792 * superblock with the numbers we get here.
795 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
797 write_lock(&journal->j_state_lock);
799 long freed = first_block - journal->j_tail;
801 if (first_block < journal->j_tail)
802 freed += journal->j_last - journal->j_first;
803 /* Update tail only if we free significant amount of space */
804 if (freed < jbd2_journal_get_max_txn_bufs(journal))
807 J_ASSERT(commit_transaction->t_state == T_COMMIT);
808 commit_transaction->t_state = T_COMMIT_DFLUSH;
809 write_unlock(&journal->j_state_lock);
812 * If the journal is not located on the file system device,
813 * then we must flush the file system device before we issue
816 if (commit_transaction->t_need_data_flush &&
817 (journal->j_fs_dev != journal->j_dev) &&
818 (journal->j_flags & JBD2_BARRIER))
819 blkdev_issue_flush(journal->j_fs_dev);
821 /* Done it all: now write the commit record asynchronously. */
822 if (jbd2_has_feature_async_commit(journal)) {
823 err = journal_submit_commit_record(journal, commit_transaction,
826 jbd2_journal_abort(journal, err);
829 blk_finish_plug(&plug);
831 /* Lo and behold: we have just managed to send a transaction to
832 the log. Before we can commit it, wait for the IO so far to
833 complete. Control buffers being written are on the
834 transaction's t_log_list queue, and metadata buffers are on
837 Wait for the buffers in reverse order. That way we are
838 less likely to be woken up until all IOs have completed, and
839 so we incur less scheduling load.
842 jbd2_debug(3, "JBD2: commit phase 3\n");
844 while (!list_empty(&io_bufs)) {
845 struct buffer_head *bh = list_entry(io_bufs.prev,
852 if (unlikely(!buffer_uptodate(bh)))
854 jbd2_unfile_log_bh(bh);
855 stats.run.rs_blocks_logged++;
858 * The list contains temporary buffer heads created by
859 * jbd2_journal_write_metadata_buffer().
861 BUFFER_TRACE(bh, "dumping temporary bh");
863 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
864 free_buffer_head(bh);
866 /* We also have to refile the corresponding shadowed buffer */
867 jh = commit_transaction->t_shadow_list->b_tprev;
869 clear_buffer_jwrite(bh);
870 J_ASSERT_BH(bh, buffer_jbddirty(bh));
871 J_ASSERT_BH(bh, !buffer_shadow(bh));
873 /* The metadata is now released for reuse, but we need
874 to remember it against this transaction so that when
875 we finally commit, we can do any checkpointing
877 JBUFFER_TRACE(jh, "file as BJ_Forget");
878 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
879 JBUFFER_TRACE(jh, "brelse shadowed buffer");
883 J_ASSERT (commit_transaction->t_shadow_list == NULL);
885 jbd2_debug(3, "JBD2: commit phase 4\n");
887 /* Here we wait for the revoke record and descriptor record buffers */
888 while (!list_empty(&log_bufs)) {
889 struct buffer_head *bh;
891 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
895 if (unlikely(!buffer_uptodate(bh)))
898 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
899 clear_buffer_jwrite(bh);
900 jbd2_unfile_log_bh(bh);
901 stats.run.rs_blocks_logged++;
902 __brelse(bh); /* One for getblk */
903 /* AKPM: bforget here */
907 jbd2_journal_abort(journal, err);
909 jbd2_debug(3, "JBD2: commit phase 5\n");
910 write_lock(&journal->j_state_lock);
911 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
912 commit_transaction->t_state = T_COMMIT_JFLUSH;
913 write_unlock(&journal->j_state_lock);
915 if (!jbd2_has_feature_async_commit(journal)) {
916 err = journal_submit_commit_record(journal, commit_transaction,
919 jbd2_journal_abort(journal, err);
922 err = journal_wait_on_commit_record(journal, cbh);
923 stats.run.rs_blocks_logged++;
924 if (jbd2_has_feature_async_commit(journal) &&
925 journal->j_flags & JBD2_BARRIER) {
926 blkdev_issue_flush(journal->j_dev);
930 jbd2_journal_abort(journal, err);
933 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
936 * Now disk caches for filesystem device are flushed so we are safe to
937 * erase checkpointed transactions from the log by updating journal
941 jbd2_update_log_tail(journal, first_tid, first_block);
943 /* End of a transaction! Finally, we can do checkpoint
944 processing: any buffers committed as a result of this
945 transaction can be removed from any checkpoint list it was on
948 jbd2_debug(3, "JBD2: commit phase 6\n");
950 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
951 J_ASSERT(commit_transaction->t_buffers == NULL);
952 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
953 J_ASSERT(commit_transaction->t_shadow_list == NULL);
957 * As there are other places (journal_unmap_buffer()) adding buffers
958 * to this list we have to be careful and hold the j_list_lock.
960 spin_lock(&journal->j_list_lock);
961 while (commit_transaction->t_forget) {
962 transaction_t *cp_transaction;
963 struct buffer_head *bh;
967 jh = commit_transaction->t_forget;
968 spin_unlock(&journal->j_list_lock);
971 * Get a reference so that bh cannot be freed before we are
975 spin_lock(&jh->b_state_lock);
976 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
979 * If there is undo-protected committed data against
980 * this buffer, then we can remove it now. If it is a
981 * buffer needing such protection, the old frozen_data
982 * field now points to a committed version of the
983 * buffer, so rotate that field to the new committed
986 * Otherwise, we can just throw away the frozen data now.
988 * We also know that the frozen data has already fired
989 * its triggers if they exist, so we can clear that too.
991 if (jh->b_committed_data) {
992 jbd2_free(jh->b_committed_data, bh->b_size);
993 jh->b_committed_data = NULL;
994 if (jh->b_frozen_data) {
995 jh->b_committed_data = jh->b_frozen_data;
996 jh->b_frozen_data = NULL;
997 jh->b_frozen_triggers = NULL;
999 } else if (jh->b_frozen_data) {
1000 jbd2_free(jh->b_frozen_data, bh->b_size);
1001 jh->b_frozen_data = NULL;
1002 jh->b_frozen_triggers = NULL;
1005 spin_lock(&journal->j_list_lock);
1006 cp_transaction = jh->b_cp_transaction;
1007 if (cp_transaction) {
1008 JBUFFER_TRACE(jh, "remove from old cp transaction");
1009 cp_transaction->t_chp_stats.cs_dropped++;
1010 __jbd2_journal_remove_checkpoint(jh);
1013 /* Only re-checkpoint the buffer_head if it is marked
1014 * dirty. If the buffer was added to the BJ_Forget list
1015 * by jbd2_journal_forget, it may no longer be dirty and
1016 * there's no point in keeping a checkpoint record for
1020 * A buffer which has been freed while still being journaled
1021 * by a previous transaction, refile the buffer to BJ_Forget of
1022 * the running transaction. If the just committed transaction
1023 * contains "add to orphan" operation, we can completely
1024 * invalidate the buffer now. We are rather through in that
1025 * since the buffer may be still accessible when blocksize <
1026 * pagesize and it is attached to the last partial page.
1028 if (buffer_freed(bh) && !jh->b_next_transaction) {
1029 struct address_space *mapping;
1031 clear_buffer_freed(bh);
1032 clear_buffer_jbddirty(bh);
1035 * Block device buffers need to stay mapped all the
1036 * time, so it is enough to clear buffer_jbddirty and
1037 * buffer_freed bits. For the file mapping buffers (i.e.
1038 * journalled data) we need to unmap buffer and clear
1039 * more bits. We also need to be careful about the check
1040 * because the data page mapping can get cleared under
1041 * our hands. Note that if mapping == NULL, we don't
1042 * need to make buffer unmapped because the page is
1043 * already detached from the mapping and buffers cannot
1046 mapping = READ_ONCE(bh->b_page->mapping);
1047 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1048 clear_buffer_mapped(bh);
1049 clear_buffer_new(bh);
1050 clear_buffer_req(bh);
1055 if (buffer_jbddirty(bh)) {
1056 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1057 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1058 if (is_journal_aborted(journal))
1059 clear_buffer_jbddirty(bh);
1061 J_ASSERT_BH(bh, !buffer_dirty(bh));
1063 * The buffer on BJ_Forget list and not jbddirty means
1064 * it has been freed by this transaction and hence it
1065 * could not have been reallocated until this
1066 * transaction has committed. *BUT* it could be
1067 * reallocated once we have written all the data to
1068 * disk and before we process the buffer on BJ_Forget
1071 if (!jh->b_next_transaction)
1074 JBUFFER_TRACE(jh, "refile or unfile buffer");
1075 drop_ref = __jbd2_journal_refile_buffer(jh);
1076 spin_unlock(&jh->b_state_lock);
1078 jbd2_journal_put_journal_head(jh);
1080 release_buffer_page(bh); /* Drops bh reference */
1083 cond_resched_lock(&journal->j_list_lock);
1085 spin_unlock(&journal->j_list_lock);
1087 * This is a bit sleazy. We use j_list_lock to protect transition
1088 * of a transaction into T_FINISHED state and calling
1089 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1090 * other checkpointing code processing the transaction...
1092 write_lock(&journal->j_state_lock);
1093 spin_lock(&journal->j_list_lock);
1095 * Now recheck if some buffers did not get attached to the transaction
1096 * while the lock was dropped...
1098 if (commit_transaction->t_forget) {
1099 spin_unlock(&journal->j_list_lock);
1100 write_unlock(&journal->j_state_lock);
1104 /* Add the transaction to the checkpoint list
1105 * __journal_remove_checkpoint() can not destroy transaction
1106 * under us because it is not marked as T_FINISHED yet */
1107 if (journal->j_checkpoint_transactions == NULL) {
1108 journal->j_checkpoint_transactions = commit_transaction;
1109 commit_transaction->t_cpnext = commit_transaction;
1110 commit_transaction->t_cpprev = commit_transaction;
1112 commit_transaction->t_cpnext =
1113 journal->j_checkpoint_transactions;
1114 commit_transaction->t_cpprev =
1115 commit_transaction->t_cpnext->t_cpprev;
1116 commit_transaction->t_cpnext->t_cpprev =
1118 commit_transaction->t_cpprev->t_cpnext =
1121 spin_unlock(&journal->j_list_lock);
1123 /* Done with this transaction! */
1125 jbd2_debug(3, "JBD2: commit phase 7\n");
1127 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1129 commit_transaction->t_start = jiffies;
1130 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1131 commit_transaction->t_start);
1134 * File the transaction statistics
1136 stats.ts_tid = commit_transaction->t_tid;
1137 stats.run.rs_handle_count =
1138 atomic_read(&commit_transaction->t_handle_count);
1139 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1140 commit_transaction->t_tid, &stats.run);
1141 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1143 commit_transaction->t_state = T_COMMIT_CALLBACK;
1144 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1145 journal->j_commit_sequence = commit_transaction->t_tid;
1146 journal->j_committing_transaction = NULL;
1147 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1150 * weight the commit time higher than the average time so we don't
1151 * react too strongly to vast changes in the commit time
1153 if (likely(journal->j_average_commit_time))
1154 journal->j_average_commit_time = (commit_time +
1155 journal->j_average_commit_time*3) / 4;
1157 journal->j_average_commit_time = commit_time;
1159 write_unlock(&journal->j_state_lock);
1161 if (journal->j_commit_callback)
1162 journal->j_commit_callback(journal, commit_transaction);
1163 if (journal->j_fc_cleanup_callback)
1164 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1166 trace_jbd2_end_commit(journal, commit_transaction);
1167 jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
1168 journal->j_commit_sequence, journal->j_tail_sequence);
1170 write_lock(&journal->j_state_lock);
1171 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1172 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1173 spin_lock(&journal->j_list_lock);
1174 commit_transaction->t_state = T_FINISHED;
1175 /* Check if the transaction can be dropped now that we are finished */
1176 if (commit_transaction->t_checkpoint_list == NULL) {
1177 __jbd2_journal_drop_transaction(journal, commit_transaction);
1178 jbd2_journal_free_transaction(commit_transaction);
1180 spin_unlock(&journal->j_list_lock);
1181 write_unlock(&journal->j_state_lock);
1182 wake_up(&journal->j_wait_done_commit);
1183 wake_up(&journal->j_fc_wait);
1186 * Calculate overall stats
1188 spin_lock(&journal->j_history_lock);
1189 journal->j_stats.ts_tid++;
1190 journal->j_stats.ts_requested += stats.ts_requested;
1191 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1192 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1193 journal->j_stats.run.rs_running += stats.run.rs_running;
1194 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1195 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1196 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1197 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1198 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1199 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1200 spin_unlock(&journal->j_history_lock);