1 // SPDX-License-Identifier: GPL-2.0+
3 * linux/fs/jbd2/commit.c
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)
69 if (atomic_read(&bh->b_count) != 1)
77 /* OK, it's a truncated page */
78 if (!trylock_page(page))
83 try_to_free_buffers(page);
92 static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
94 struct commit_header *h;
97 if (!jbd2_journal_has_csum_v2or3(j))
100 h = (struct commit_header *)(bh->b_data);
101 h->h_chksum_type = 0;
102 h->h_chksum_size = 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);
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
114 * Returns 1 if the journal needs to be aborted or 0 on success
116 static int journal_submit_commit_record(journal_t *journal,
117 transaction_t *commit_transaction,
118 struct buffer_head **cbh,
121 struct commit_header *tmp;
122 struct buffer_head *bh;
124 struct timespec64 now;
128 if (is_journal_aborted(journal))
131 bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
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);
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);
146 jbd2_commit_block_csum_set(journal, bh);
148 BUFFER_TRACE(bh, "submit commit block");
150 clear_buffer_dirty(bh);
151 set_buffer_uptodate(bh);
152 bh->b_end_io = journal_end_buffer_io_sync;
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);
159 ret = submit_bh(REQ_OP_WRITE, REQ_SYNC, 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);
303 spin_lock(&journal->j_list_lock);
304 jinode->i_flags &= ~JI_COMMIT_RUNNING;
306 wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
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);
319 jinode->i_transaction = NULL;
320 jinode->i_dirty_start = 0;
321 jinode->i_dirty_end = 0;
324 spin_unlock(&journal->j_list_lock);
329 static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
331 struct page *page = bh->b_page;
335 addr = kmap_atomic(page);
336 checksum = crc32_be(crc32_sum,
337 (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
343 static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
344 unsigned long long block)
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);
351 static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
352 struct buffer_head *bh, __u32 sequence)
354 journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
355 struct page *page = bh->b_page;
360 if (!jbd2_journal_has_csum_v2or3(j))
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),
370 if (jbd2_has_feature_csum3(j))
371 tag3->t_checksum = cpu_to_be32(csum32);
373 tag->t_checksum = cpu_to_be16(csum32);
376 * jbd2_journal_commit_transaction
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.
381 void jbd2_journal_commit_transaction(journal_t *journal)
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;
391 unsigned long long blocknr;
395 journal_block_tag_t *tag = NULL;
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;
412 if (jbd2_journal_has_csum_v2or3(journal))
413 csum_size = sizeof(struct jbd2_journal_block_tail);
416 * First job: lock down the current transaction and wait for
417 * all outstanding updates to complete.
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);
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.
430 jbd2_journal_update_sb_log_tail(journal,
431 journal->j_tail_sequence,
434 mutex_unlock(&journal->j_checkpoint_mutex);
436 jbd_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 jbd_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;
491 write_unlock(&journal->j_state_lock);
493 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
494 journal->j_max_transaction_buffers);
497 * First thing we are allowed to do is to discard any remaining
498 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
499 * that there are no such buffers: if a large filesystem
500 * operation like a truncate needs to split itself over multiple
501 * transactions, then it may try to do a jbd2_journal_restart() while
502 * there are still BJ_Reserved buffers outstanding. These must
503 * be released cleanly from the current transaction.
505 * In this case, the filesystem must still reserve write access
506 * again before modifying the buffer in the new transaction, but
507 * we do not require it to remember exactly which old buffers it
508 * has reserved. This is consistent with the existing behaviour
509 * that multiple jbd2_journal_get_write_access() calls to the same
510 * buffer are perfectly permissible.
512 while (commit_transaction->t_reserved_list) {
513 jh = commit_transaction->t_reserved_list;
514 JBUFFER_TRACE(jh, "reserved, unused: refile");
516 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
517 * leave undo-committed data.
519 if (jh->b_committed_data) {
520 struct buffer_head *bh = jh2bh(jh);
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);
527 jbd2_journal_refile_buffer(journal, jh);
531 * Now try to drop any written-back buffers from the journal's
532 * checkpoint lists. We do this *before* commit because it potentially
535 spin_lock(&journal->j_list_lock);
536 __jbd2_journal_clean_checkpoint_list(journal, false);
537 spin_unlock(&journal->j_list_lock);
539 jbd_debug(3, "JBD2: commit phase 1\n");
542 * Clear revoked flag to reflect there is no revoked buffers
543 * in the next transaction which is going to be started.
545 jbd2_clear_buffer_revoked_flags(journal);
548 * Switch to a new revoke table.
550 jbd2_journal_switch_revoke_table(journal);
553 * Reserved credits cannot be claimed anymore, free them
555 atomic_sub(atomic_read(&journal->j_reserved_credits),
556 &commit_transaction->t_outstanding_credits);
558 write_lock(&journal->j_state_lock);
559 trace_jbd2_commit_flushing(journal, commit_transaction);
560 stats.run.rs_flushing = jiffies;
561 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
562 stats.run.rs_flushing);
564 commit_transaction->t_state = T_FLUSH;
565 journal->j_committing_transaction = commit_transaction;
566 journal->j_running_transaction = NULL;
567 start_time = ktime_get();
568 commit_transaction->t_log_start = journal->j_head;
569 wake_up(&journal->j_wait_transaction_locked);
570 write_unlock(&journal->j_state_lock);
572 jbd_debug(3, "JBD2: commit phase 2a\n");
575 * Now start flushing things to disk, in the order they appear
576 * on the transaction lists. Data blocks go first.
578 err = journal_submit_data_buffers(journal, commit_transaction);
580 jbd2_journal_abort(journal, err);
582 blk_start_plug(&plug);
583 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
585 jbd_debug(3, "JBD2: commit phase 2b\n");
588 * Way to go: we have now written out all of the data for a
589 * transaction! Now comes the tricky part: we need to write out
590 * metadata. Loop over the transaction's entire buffer list:
592 write_lock(&journal->j_state_lock);
593 commit_transaction->t_state = T_COMMIT;
594 write_unlock(&journal->j_state_lock);
596 trace_jbd2_commit_logging(journal, commit_transaction);
597 stats.run.rs_logging = jiffies;
598 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
599 stats.run.rs_logging);
600 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
601 stats.run.rs_blocks_logged = 0;
603 J_ASSERT(commit_transaction->t_nr_buffers <=
604 atomic_read(&commit_transaction->t_outstanding_credits));
609 while (commit_transaction->t_buffers) {
611 /* Find the next buffer to be journaled... */
613 jh = commit_transaction->t_buffers;
615 /* If we're in abort mode, we just un-journal the buffer and
618 if (is_journal_aborted(journal)) {
619 clear_buffer_jbddirty(jh2bh(jh));
620 JBUFFER_TRACE(jh, "journal is aborting: refile");
621 jbd2_buffer_abort_trigger(jh,
623 jh->b_frozen_triggers :
625 jbd2_journal_refile_buffer(journal, jh);
626 /* If that was the last one, we need to clean up
627 * any descriptor buffers which may have been
628 * already allocated, even if we are now
630 if (!commit_transaction->t_buffers)
631 goto start_journal_io;
635 /* Make sure we have a descriptor block in which to
636 record the metadata buffer. */
639 J_ASSERT (bufs == 0);
641 jbd_debug(4, "JBD2: get descriptor\n");
643 descriptor = jbd2_journal_get_descriptor_buffer(
645 JBD2_DESCRIPTOR_BLOCK);
647 jbd2_journal_abort(journal, -EIO);
651 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
652 (unsigned long long)descriptor->b_blocknr,
654 tagp = &descriptor->b_data[sizeof(journal_header_t)];
655 space_left = descriptor->b_size -
656 sizeof(journal_header_t);
658 set_buffer_jwrite(descriptor);
659 set_buffer_dirty(descriptor);
660 wbuf[bufs++] = descriptor;
662 /* Record it so that we can wait for IO
664 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
665 jbd2_file_log_bh(&log_bufs, descriptor);
668 /* Where is the buffer to be written? */
670 err = jbd2_journal_next_log_block(journal, &blocknr);
671 /* If the block mapping failed, just abandon the buffer
672 and repeat this loop: we'll fall into the
673 refile-on-abort condition above. */
675 jbd2_journal_abort(journal, err);
680 * start_this_handle() uses t_outstanding_credits to determine
681 * the free space in the log.
683 atomic_dec(&commit_transaction->t_outstanding_credits);
685 /* Bump b_count to prevent truncate from stumbling over
686 the shadowed buffer! @@@ This can go if we ever get
687 rid of the shadow pairing of buffers. */
688 atomic_inc(&jh2bh(jh)->b_count);
691 * Make a temporary IO buffer with which to write it out
692 * (this will requeue the metadata buffer to BJ_Shadow).
694 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
695 JBUFFER_TRACE(jh, "ph3: write metadata");
696 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
697 jh, &wbuf[bufs], blocknr);
699 jbd2_journal_abort(journal, flags);
702 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
704 /* Record the new block's tag in the current descriptor
709 tag_flag |= JBD2_FLAG_ESCAPE;
711 tag_flag |= JBD2_FLAG_SAME_UUID;
713 tag = (journal_block_tag_t *) tagp;
714 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
715 tag->t_flags = cpu_to_be16(tag_flag);
716 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
717 commit_transaction->t_tid);
719 space_left -= tag_bytes;
723 memcpy (tagp, journal->j_uuid, 16);
729 /* If there's no more to do, or if the descriptor is full,
732 if (bufs == journal->j_wbufsize ||
733 commit_transaction->t_buffers == NULL ||
734 space_left < tag_bytes + 16 + csum_size) {
736 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
738 /* Write an end-of-descriptor marker before
739 submitting the IOs. "tag" still points to
740 the last tag we set up. */
742 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
745 jbd2_descriptor_block_csum_set(journal,
748 for (i = 0; i < bufs; i++) {
749 struct buffer_head *bh = wbuf[i];
753 if (jbd2_has_feature_checksum(journal)) {
755 jbd2_checksum_data(crc32_sum, bh);
759 clear_buffer_dirty(bh);
760 set_buffer_uptodate(bh);
761 bh->b_end_io = journal_end_buffer_io_sync;
762 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
766 /* Force a new descriptor to be generated next
767 time round the loop. */
773 err = journal_finish_inode_data_buffers(journal, commit_transaction);
776 "JBD2: Detected IO errors while flushing file data "
777 "on %s\n", journal->j_devname);
778 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
779 jbd2_journal_abort(journal, err);
784 * Get current oldest transaction in the log before we issue flush
785 * to the filesystem device. After the flush we can be sure that
786 * blocks of all older transactions are checkpointed to persistent
787 * storage and we will be safe to update journal start in the
788 * superblock with the numbers we get here.
791 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
793 write_lock(&journal->j_state_lock);
795 long freed = first_block - journal->j_tail;
797 if (first_block < journal->j_tail)
798 freed += journal->j_last - journal->j_first;
799 /* Update tail only if we free significant amount of space */
800 if (freed < jbd2_journal_get_max_txn_bufs(journal))
803 J_ASSERT(commit_transaction->t_state == T_COMMIT);
804 commit_transaction->t_state = T_COMMIT_DFLUSH;
805 write_unlock(&journal->j_state_lock);
808 * If the journal is not located on the file system device,
809 * then we must flush the file system device before we issue
812 if (commit_transaction->t_need_data_flush &&
813 (journal->j_fs_dev != journal->j_dev) &&
814 (journal->j_flags & JBD2_BARRIER))
815 blkdev_issue_flush(journal->j_fs_dev);
817 /* Done it all: now write the commit record asynchronously. */
818 if (jbd2_has_feature_async_commit(journal)) {
819 err = journal_submit_commit_record(journal, commit_transaction,
822 jbd2_journal_abort(journal, err);
825 blk_finish_plug(&plug);
827 /* Lo and behold: we have just managed to send a transaction to
828 the log. Before we can commit it, wait for the IO so far to
829 complete. Control buffers being written are on the
830 transaction's t_log_list queue, and metadata buffers are on
833 Wait for the buffers in reverse order. That way we are
834 less likely to be woken up until all IOs have completed, and
835 so we incur less scheduling load.
838 jbd_debug(3, "JBD2: commit phase 3\n");
840 while (!list_empty(&io_bufs)) {
841 struct buffer_head *bh = list_entry(io_bufs.prev,
848 if (unlikely(!buffer_uptodate(bh)))
850 jbd2_unfile_log_bh(bh);
851 stats.run.rs_blocks_logged++;
854 * The list contains temporary buffer heads created by
855 * jbd2_journal_write_metadata_buffer().
857 BUFFER_TRACE(bh, "dumping temporary bh");
859 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
860 free_buffer_head(bh);
862 /* We also have to refile the corresponding shadowed buffer */
863 jh = commit_transaction->t_shadow_list->b_tprev;
865 clear_buffer_jwrite(bh);
866 J_ASSERT_BH(bh, buffer_jbddirty(bh));
867 J_ASSERT_BH(bh, !buffer_shadow(bh));
869 /* The metadata is now released for reuse, but we need
870 to remember it against this transaction so that when
871 we finally commit, we can do any checkpointing
873 JBUFFER_TRACE(jh, "file as BJ_Forget");
874 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
875 JBUFFER_TRACE(jh, "brelse shadowed buffer");
879 J_ASSERT (commit_transaction->t_shadow_list == NULL);
881 jbd_debug(3, "JBD2: commit phase 4\n");
883 /* Here we wait for the revoke record and descriptor record buffers */
884 while (!list_empty(&log_bufs)) {
885 struct buffer_head *bh;
887 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
891 if (unlikely(!buffer_uptodate(bh)))
894 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
895 clear_buffer_jwrite(bh);
896 jbd2_unfile_log_bh(bh);
897 stats.run.rs_blocks_logged++;
898 __brelse(bh); /* One for getblk */
899 /* AKPM: bforget here */
903 jbd2_journal_abort(journal, err);
905 jbd_debug(3, "JBD2: commit phase 5\n");
906 write_lock(&journal->j_state_lock);
907 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
908 commit_transaction->t_state = T_COMMIT_JFLUSH;
909 write_unlock(&journal->j_state_lock);
911 if (!jbd2_has_feature_async_commit(journal)) {
912 err = journal_submit_commit_record(journal, commit_transaction,
915 jbd2_journal_abort(journal, err);
918 err = journal_wait_on_commit_record(journal, cbh);
919 stats.run.rs_blocks_logged++;
920 if (jbd2_has_feature_async_commit(journal) &&
921 journal->j_flags & JBD2_BARRIER) {
922 blkdev_issue_flush(journal->j_dev);
926 jbd2_journal_abort(journal, err);
929 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
932 * Now disk caches for filesystem device are flushed so we are safe to
933 * erase checkpointed transactions from the log by updating journal
937 jbd2_update_log_tail(journal, first_tid, first_block);
939 /* End of a transaction! Finally, we can do checkpoint
940 processing: any buffers committed as a result of this
941 transaction can be removed from any checkpoint list it was on
944 jbd_debug(3, "JBD2: commit phase 6\n");
946 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
947 J_ASSERT(commit_transaction->t_buffers == NULL);
948 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
949 J_ASSERT(commit_transaction->t_shadow_list == NULL);
953 * As there are other places (journal_unmap_buffer()) adding buffers
954 * to this list we have to be careful and hold the j_list_lock.
956 spin_lock(&journal->j_list_lock);
957 while (commit_transaction->t_forget) {
958 transaction_t *cp_transaction;
959 struct buffer_head *bh;
963 jh = commit_transaction->t_forget;
964 spin_unlock(&journal->j_list_lock);
967 * Get a reference so that bh cannot be freed before we are
971 spin_lock(&jh->b_state_lock);
972 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
975 * If there is undo-protected committed data against
976 * this buffer, then we can remove it now. If it is a
977 * buffer needing such protection, the old frozen_data
978 * field now points to a committed version of the
979 * buffer, so rotate that field to the new committed
982 * Otherwise, we can just throw away the frozen data now.
984 * We also know that the frozen data has already fired
985 * its triggers if they exist, so we can clear that too.
987 if (jh->b_committed_data) {
988 jbd2_free(jh->b_committed_data, bh->b_size);
989 jh->b_committed_data = NULL;
990 if (jh->b_frozen_data) {
991 jh->b_committed_data = jh->b_frozen_data;
992 jh->b_frozen_data = NULL;
993 jh->b_frozen_triggers = NULL;
995 } else if (jh->b_frozen_data) {
996 jbd2_free(jh->b_frozen_data, bh->b_size);
997 jh->b_frozen_data = NULL;
998 jh->b_frozen_triggers = NULL;
1001 spin_lock(&journal->j_list_lock);
1002 cp_transaction = jh->b_cp_transaction;
1003 if (cp_transaction) {
1004 JBUFFER_TRACE(jh, "remove from old cp transaction");
1005 cp_transaction->t_chp_stats.cs_dropped++;
1006 __jbd2_journal_remove_checkpoint(jh);
1009 /* Only re-checkpoint the buffer_head if it is marked
1010 * dirty. If the buffer was added to the BJ_Forget list
1011 * by jbd2_journal_forget, it may no longer be dirty and
1012 * there's no point in keeping a checkpoint record for
1016 * A buffer which has been freed while still being journaled
1017 * by a previous transaction, refile the buffer to BJ_Forget of
1018 * the running transaction. If the just committed transaction
1019 * contains "add to orphan" operation, we can completely
1020 * invalidate the buffer now. We are rather through in that
1021 * since the buffer may be still accessible when blocksize <
1022 * pagesize and it is attached to the last partial page.
1024 if (buffer_freed(bh) && !jh->b_next_transaction) {
1025 struct address_space *mapping;
1027 clear_buffer_freed(bh);
1028 clear_buffer_jbddirty(bh);
1031 * Block device buffers need to stay mapped all the
1032 * time, so it is enough to clear buffer_jbddirty and
1033 * buffer_freed bits. For the file mapping buffers (i.e.
1034 * journalled data) we need to unmap buffer and clear
1035 * more bits. We also need to be careful about the check
1036 * because the data page mapping can get cleared under
1037 * our hands. Note that if mapping == NULL, we don't
1038 * need to make buffer unmapped because the page is
1039 * already detached from the mapping and buffers cannot
1042 mapping = READ_ONCE(bh->b_page->mapping);
1043 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1044 clear_buffer_mapped(bh);
1045 clear_buffer_new(bh);
1046 clear_buffer_req(bh);
1051 if (buffer_jbddirty(bh)) {
1052 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1053 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1054 if (is_journal_aborted(journal))
1055 clear_buffer_jbddirty(bh);
1057 J_ASSERT_BH(bh, !buffer_dirty(bh));
1059 * The buffer on BJ_Forget list and not jbddirty means
1060 * it has been freed by this transaction and hence it
1061 * could not have been reallocated until this
1062 * transaction has committed. *BUT* it could be
1063 * reallocated once we have written all the data to
1064 * disk and before we process the buffer on BJ_Forget
1067 if (!jh->b_next_transaction)
1070 JBUFFER_TRACE(jh, "refile or unfile buffer");
1071 drop_ref = __jbd2_journal_refile_buffer(jh);
1072 spin_unlock(&jh->b_state_lock);
1074 jbd2_journal_put_journal_head(jh);
1076 release_buffer_page(bh); /* Drops bh reference */
1079 cond_resched_lock(&journal->j_list_lock);
1081 spin_unlock(&journal->j_list_lock);
1083 * This is a bit sleazy. We use j_list_lock to protect transition
1084 * of a transaction into T_FINISHED state and calling
1085 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1086 * other checkpointing code processing the transaction...
1088 write_lock(&journal->j_state_lock);
1089 spin_lock(&journal->j_list_lock);
1091 * Now recheck if some buffers did not get attached to the transaction
1092 * while the lock was dropped...
1094 if (commit_transaction->t_forget) {
1095 spin_unlock(&journal->j_list_lock);
1096 write_unlock(&journal->j_state_lock);
1100 /* Add the transaction to the checkpoint list
1101 * __journal_remove_checkpoint() can not destroy transaction
1102 * under us because it is not marked as T_FINISHED yet */
1103 if (journal->j_checkpoint_transactions == NULL) {
1104 journal->j_checkpoint_transactions = commit_transaction;
1105 commit_transaction->t_cpnext = commit_transaction;
1106 commit_transaction->t_cpprev = commit_transaction;
1108 commit_transaction->t_cpnext =
1109 journal->j_checkpoint_transactions;
1110 commit_transaction->t_cpprev =
1111 commit_transaction->t_cpnext->t_cpprev;
1112 commit_transaction->t_cpnext->t_cpprev =
1114 commit_transaction->t_cpprev->t_cpnext =
1117 spin_unlock(&journal->j_list_lock);
1119 /* Done with this transaction! */
1121 jbd_debug(3, "JBD2: commit phase 7\n");
1123 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1125 commit_transaction->t_start = jiffies;
1126 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1127 commit_transaction->t_start);
1130 * File the transaction statistics
1132 stats.ts_tid = commit_transaction->t_tid;
1133 stats.run.rs_handle_count =
1134 atomic_read(&commit_transaction->t_handle_count);
1135 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1136 commit_transaction->t_tid, &stats.run);
1137 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1139 commit_transaction->t_state = T_COMMIT_CALLBACK;
1140 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1141 journal->j_commit_sequence = commit_transaction->t_tid;
1142 journal->j_committing_transaction = NULL;
1143 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1146 * weight the commit time higher than the average time so we don't
1147 * react too strongly to vast changes in the commit time
1149 if (likely(journal->j_average_commit_time))
1150 journal->j_average_commit_time = (commit_time +
1151 journal->j_average_commit_time*3) / 4;
1153 journal->j_average_commit_time = commit_time;
1155 write_unlock(&journal->j_state_lock);
1157 if (journal->j_commit_callback)
1158 journal->j_commit_callback(journal, commit_transaction);
1159 if (journal->j_fc_cleanup_callback)
1160 journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
1162 trace_jbd2_end_commit(journal, commit_transaction);
1163 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1164 journal->j_commit_sequence, journal->j_tail_sequence);
1166 write_lock(&journal->j_state_lock);
1167 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1168 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1169 spin_lock(&journal->j_list_lock);
1170 commit_transaction->t_state = T_FINISHED;
1171 /* Check if the transaction can be dropped now that we are finished */
1172 if (commit_transaction->t_checkpoint_list == NULL &&
1173 commit_transaction->t_checkpoint_io_list == NULL) {
1174 __jbd2_journal_drop_transaction(journal, commit_transaction);
1175 jbd2_journal_free_transaction(commit_transaction);
1177 spin_unlock(&journal->j_list_lock);
1178 write_unlock(&journal->j_state_lock);
1179 wake_up(&journal->j_wait_done_commit);
1180 wake_up(&journal->j_fc_wait);
1183 * Calculate overall stats
1185 spin_lock(&journal->j_history_lock);
1186 journal->j_stats.ts_tid++;
1187 journal->j_stats.ts_requested += stats.ts_requested;
1188 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1189 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1190 journal->j_stats.run.rs_running += stats.run.rs_running;
1191 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1192 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1193 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1194 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1195 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1196 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1197 spin_unlock(&journal->j_history_lock);