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)
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 spin_lock(&commit_transaction->t_handle_lock);
488 while (atomic_read(&commit_transaction->t_updates)) {
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);
497 write_lock(&journal->j_state_lock);
498 spin_lock(&commit_transaction->t_handle_lock);
500 finish_wait(&journal->j_wait_updates, &wait);
502 spin_unlock(&commit_transaction->t_handle_lock);
503 commit_transaction->t_state = T_SWITCH;
505 J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
506 journal->j_max_transaction_buffers);
509 * First thing we are allowed to do is to discard any remaining
510 * BJ_Reserved buffers. Note, it is _not_ permissible to assume
511 * that there are no such buffers: if a large filesystem
512 * operation like a truncate needs to split itself over multiple
513 * transactions, then it may try to do a jbd2_journal_restart() while
514 * there are still BJ_Reserved buffers outstanding. These must
515 * be released cleanly from the current transaction.
517 * In this case, the filesystem must still reserve write access
518 * again before modifying the buffer in the new transaction, but
519 * we do not require it to remember exactly which old buffers it
520 * has reserved. This is consistent with the existing behaviour
521 * that multiple jbd2_journal_get_write_access() calls to the same
522 * buffer are perfectly permissible.
523 * We use journal->j_state_lock here to serialize processing of
524 * t_reserved_list with eviction of buffers from journal_unmap_buffer().
526 while (commit_transaction->t_reserved_list) {
527 jh = commit_transaction->t_reserved_list;
528 JBUFFER_TRACE(jh, "reserved, unused: refile");
530 * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
531 * leave undo-committed data.
533 if (jh->b_committed_data) {
534 struct buffer_head *bh = jh2bh(jh);
536 spin_lock(&jh->b_state_lock);
537 jbd2_free(jh->b_committed_data, bh->b_size);
538 jh->b_committed_data = NULL;
539 spin_unlock(&jh->b_state_lock);
541 jbd2_journal_refile_buffer(journal, jh);
544 write_unlock(&journal->j_state_lock);
546 * Now try to drop any written-back buffers from the journal's
547 * checkpoint lists. We do this *before* commit because it potentially
550 spin_lock(&journal->j_list_lock);
551 __jbd2_journal_clean_checkpoint_list(journal, false);
552 spin_unlock(&journal->j_list_lock);
554 jbd_debug(3, "JBD2: commit phase 1\n");
557 * Clear revoked flag to reflect there is no revoked buffers
558 * in the next transaction which is going to be started.
560 jbd2_clear_buffer_revoked_flags(journal);
563 * Switch to a new revoke table.
565 jbd2_journal_switch_revoke_table(journal);
567 write_lock(&journal->j_state_lock);
569 * Reserved credits cannot be claimed anymore, free them
571 atomic_sub(atomic_read(&journal->j_reserved_credits),
572 &commit_transaction->t_outstanding_credits);
574 trace_jbd2_commit_flushing(journal, commit_transaction);
575 stats.run.rs_flushing = jiffies;
576 stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
577 stats.run.rs_flushing);
579 commit_transaction->t_state = T_FLUSH;
580 journal->j_committing_transaction = commit_transaction;
581 journal->j_running_transaction = NULL;
582 start_time = ktime_get();
583 commit_transaction->t_log_start = journal->j_head;
584 wake_up_all(&journal->j_wait_transaction_locked);
585 write_unlock(&journal->j_state_lock);
587 jbd_debug(3, "JBD2: commit phase 2a\n");
590 * Now start flushing things to disk, in the order they appear
591 * on the transaction lists. Data blocks go first.
593 err = journal_submit_data_buffers(journal, commit_transaction);
595 jbd2_journal_abort(journal, err);
597 blk_start_plug(&plug);
598 jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
600 jbd_debug(3, "JBD2: commit phase 2b\n");
603 * Way to go: we have now written out all of the data for a
604 * transaction! Now comes the tricky part: we need to write out
605 * metadata. Loop over the transaction's entire buffer list:
607 write_lock(&journal->j_state_lock);
608 commit_transaction->t_state = T_COMMIT;
609 write_unlock(&journal->j_state_lock);
611 trace_jbd2_commit_logging(journal, commit_transaction);
612 stats.run.rs_logging = jiffies;
613 stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
614 stats.run.rs_logging);
615 stats.run.rs_blocks = commit_transaction->t_nr_buffers;
616 stats.run.rs_blocks_logged = 0;
618 J_ASSERT(commit_transaction->t_nr_buffers <=
619 atomic_read(&commit_transaction->t_outstanding_credits));
624 while (commit_transaction->t_buffers) {
626 /* Find the next buffer to be journaled... */
628 jh = commit_transaction->t_buffers;
630 /* If we're in abort mode, we just un-journal the buffer and
633 if (is_journal_aborted(journal)) {
634 clear_buffer_jbddirty(jh2bh(jh));
635 JBUFFER_TRACE(jh, "journal is aborting: refile");
636 jbd2_buffer_abort_trigger(jh,
638 jh->b_frozen_triggers :
640 jbd2_journal_refile_buffer(journal, jh);
641 /* If that was the last one, we need to clean up
642 * any descriptor buffers which may have been
643 * already allocated, even if we are now
645 if (!commit_transaction->t_buffers)
646 goto start_journal_io;
650 /* Make sure we have a descriptor block in which to
651 record the metadata buffer. */
654 J_ASSERT (bufs == 0);
656 jbd_debug(4, "JBD2: get descriptor\n");
658 descriptor = jbd2_journal_get_descriptor_buffer(
660 JBD2_DESCRIPTOR_BLOCK);
662 jbd2_journal_abort(journal, -EIO);
666 jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
667 (unsigned long long)descriptor->b_blocknr,
669 tagp = &descriptor->b_data[sizeof(journal_header_t)];
670 space_left = descriptor->b_size -
671 sizeof(journal_header_t);
673 set_buffer_jwrite(descriptor);
674 set_buffer_dirty(descriptor);
675 wbuf[bufs++] = descriptor;
677 /* Record it so that we can wait for IO
679 BUFFER_TRACE(descriptor, "ph3: file as descriptor");
680 jbd2_file_log_bh(&log_bufs, descriptor);
683 /* Where is the buffer to be written? */
685 err = jbd2_journal_next_log_block(journal, &blocknr);
686 /* If the block mapping failed, just abandon the buffer
687 and repeat this loop: we'll fall into the
688 refile-on-abort condition above. */
690 jbd2_journal_abort(journal, err);
695 * start_this_handle() uses t_outstanding_credits to determine
696 * the free space in the log.
698 atomic_dec(&commit_transaction->t_outstanding_credits);
700 /* Bump b_count to prevent truncate from stumbling over
701 the shadowed buffer! @@@ This can go if we ever get
702 rid of the shadow pairing of buffers. */
703 atomic_inc(&jh2bh(jh)->b_count);
706 * Make a temporary IO buffer with which to write it out
707 * (this will requeue the metadata buffer to BJ_Shadow).
709 set_bit(BH_JWrite, &jh2bh(jh)->b_state);
710 JBUFFER_TRACE(jh, "ph3: write metadata");
711 flags = jbd2_journal_write_metadata_buffer(commit_transaction,
712 jh, &wbuf[bufs], blocknr);
714 jbd2_journal_abort(journal, flags);
717 jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
719 /* Record the new block's tag in the current descriptor
724 tag_flag |= JBD2_FLAG_ESCAPE;
726 tag_flag |= JBD2_FLAG_SAME_UUID;
728 tag = (journal_block_tag_t *) tagp;
729 write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
730 tag->t_flags = cpu_to_be16(tag_flag);
731 jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
732 commit_transaction->t_tid);
734 space_left -= tag_bytes;
738 memcpy (tagp, journal->j_uuid, 16);
744 /* If there's no more to do, or if the descriptor is full,
747 if (bufs == journal->j_wbufsize ||
748 commit_transaction->t_buffers == NULL ||
749 space_left < tag_bytes + 16 + csum_size) {
751 jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
753 /* Write an end-of-descriptor marker before
754 submitting the IOs. "tag" still points to
755 the last tag we set up. */
757 tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
760 jbd2_descriptor_block_csum_set(journal,
763 for (i = 0; i < bufs; i++) {
764 struct buffer_head *bh = wbuf[i];
768 if (jbd2_has_feature_checksum(journal)) {
770 jbd2_checksum_data(crc32_sum, bh);
774 clear_buffer_dirty(bh);
775 set_buffer_uptodate(bh);
776 bh->b_end_io = journal_end_buffer_io_sync;
777 submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
781 /* Force a new descriptor to be generated next
782 time round the loop. */
788 err = journal_finish_inode_data_buffers(journal, commit_transaction);
791 "JBD2: Detected IO errors while flushing file data "
792 "on %s\n", journal->j_devname);
793 if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
794 jbd2_journal_abort(journal, err);
799 * Get current oldest transaction in the log before we issue flush
800 * to the filesystem device. After the flush we can be sure that
801 * blocks of all older transactions are checkpointed to persistent
802 * storage and we will be safe to update journal start in the
803 * superblock with the numbers we get here.
806 jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
808 write_lock(&journal->j_state_lock);
810 long freed = first_block - journal->j_tail;
812 if (first_block < journal->j_tail)
813 freed += journal->j_last - journal->j_first;
814 /* Update tail only if we free significant amount of space */
815 if (freed < jbd2_journal_get_max_txn_bufs(journal))
818 J_ASSERT(commit_transaction->t_state == T_COMMIT);
819 commit_transaction->t_state = T_COMMIT_DFLUSH;
820 write_unlock(&journal->j_state_lock);
823 * If the journal is not located on the file system device,
824 * then we must flush the file system device before we issue
827 if (commit_transaction->t_need_data_flush &&
828 (journal->j_fs_dev != journal->j_dev) &&
829 (journal->j_flags & JBD2_BARRIER))
830 blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS);
832 /* Done it all: now write the commit record asynchronously. */
833 if (jbd2_has_feature_async_commit(journal)) {
834 err = journal_submit_commit_record(journal, commit_transaction,
837 jbd2_journal_abort(journal, err);
840 blk_finish_plug(&plug);
842 /* Lo and behold: we have just managed to send a transaction to
843 the log. Before we can commit it, wait for the IO so far to
844 complete. Control buffers being written are on the
845 transaction's t_log_list queue, and metadata buffers are on
848 Wait for the buffers in reverse order. That way we are
849 less likely to be woken up until all IOs have completed, and
850 so we incur less scheduling load.
853 jbd_debug(3, "JBD2: commit phase 3\n");
855 while (!list_empty(&io_bufs)) {
856 struct buffer_head *bh = list_entry(io_bufs.prev,
863 if (unlikely(!buffer_uptodate(bh)))
865 jbd2_unfile_log_bh(bh);
866 stats.run.rs_blocks_logged++;
869 * The list contains temporary buffer heads created by
870 * jbd2_journal_write_metadata_buffer().
872 BUFFER_TRACE(bh, "dumping temporary bh");
874 J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
875 free_buffer_head(bh);
877 /* We also have to refile the corresponding shadowed buffer */
878 jh = commit_transaction->t_shadow_list->b_tprev;
880 clear_buffer_jwrite(bh);
881 J_ASSERT_BH(bh, buffer_jbddirty(bh));
882 J_ASSERT_BH(bh, !buffer_shadow(bh));
884 /* The metadata is now released for reuse, but we need
885 to remember it against this transaction so that when
886 we finally commit, we can do any checkpointing
888 JBUFFER_TRACE(jh, "file as BJ_Forget");
889 jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
890 JBUFFER_TRACE(jh, "brelse shadowed buffer");
894 J_ASSERT (commit_transaction->t_shadow_list == NULL);
896 jbd_debug(3, "JBD2: commit phase 4\n");
898 /* Here we wait for the revoke record and descriptor record buffers */
899 while (!list_empty(&log_bufs)) {
900 struct buffer_head *bh;
902 bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
906 if (unlikely(!buffer_uptodate(bh)))
909 BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
910 clear_buffer_jwrite(bh);
911 jbd2_unfile_log_bh(bh);
912 stats.run.rs_blocks_logged++;
913 __brelse(bh); /* One for getblk */
914 /* AKPM: bforget here */
918 jbd2_journal_abort(journal, err);
920 jbd_debug(3, "JBD2: commit phase 5\n");
921 write_lock(&journal->j_state_lock);
922 J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
923 commit_transaction->t_state = T_COMMIT_JFLUSH;
924 write_unlock(&journal->j_state_lock);
926 if (!jbd2_has_feature_async_commit(journal)) {
927 err = journal_submit_commit_record(journal, commit_transaction,
930 jbd2_journal_abort(journal, err);
933 err = journal_wait_on_commit_record(journal, cbh);
934 stats.run.rs_blocks_logged++;
935 if (jbd2_has_feature_async_commit(journal) &&
936 journal->j_flags & JBD2_BARRIER) {
937 blkdev_issue_flush(journal->j_dev, GFP_NOFS);
941 jbd2_journal_abort(journal, err);
944 atomic_read(&commit_transaction->t_outstanding_credits) < 0);
947 * Now disk caches for filesystem device are flushed so we are safe to
948 * erase checkpointed transactions from the log by updating journal
952 jbd2_update_log_tail(journal, first_tid, first_block);
954 /* End of a transaction! Finally, we can do checkpoint
955 processing: any buffers committed as a result of this
956 transaction can be removed from any checkpoint list it was on
959 jbd_debug(3, "JBD2: commit phase 6\n");
961 J_ASSERT(list_empty(&commit_transaction->t_inode_list));
962 J_ASSERT(commit_transaction->t_buffers == NULL);
963 J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
964 J_ASSERT(commit_transaction->t_shadow_list == NULL);
968 * As there are other places (journal_unmap_buffer()) adding buffers
969 * to this list we have to be careful and hold the j_list_lock.
971 spin_lock(&journal->j_list_lock);
972 while (commit_transaction->t_forget) {
973 transaction_t *cp_transaction;
974 struct buffer_head *bh;
978 jh = commit_transaction->t_forget;
979 spin_unlock(&journal->j_list_lock);
982 * Get a reference so that bh cannot be freed before we are
986 spin_lock(&jh->b_state_lock);
987 J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
990 * If there is undo-protected committed data against
991 * this buffer, then we can remove it now. If it is a
992 * buffer needing such protection, the old frozen_data
993 * field now points to a committed version of the
994 * buffer, so rotate that field to the new committed
997 * Otherwise, we can just throw away the frozen data now.
999 * We also know that the frozen data has already fired
1000 * its triggers if they exist, so we can clear that too.
1002 if (jh->b_committed_data) {
1003 jbd2_free(jh->b_committed_data, bh->b_size);
1004 jh->b_committed_data = NULL;
1005 if (jh->b_frozen_data) {
1006 jh->b_committed_data = jh->b_frozen_data;
1007 jh->b_frozen_data = NULL;
1008 jh->b_frozen_triggers = NULL;
1010 } else if (jh->b_frozen_data) {
1011 jbd2_free(jh->b_frozen_data, bh->b_size);
1012 jh->b_frozen_data = NULL;
1013 jh->b_frozen_triggers = NULL;
1016 spin_lock(&journal->j_list_lock);
1017 cp_transaction = jh->b_cp_transaction;
1018 if (cp_transaction) {
1019 JBUFFER_TRACE(jh, "remove from old cp transaction");
1020 cp_transaction->t_chp_stats.cs_dropped++;
1021 __jbd2_journal_remove_checkpoint(jh);
1024 /* Only re-checkpoint the buffer_head if it is marked
1025 * dirty. If the buffer was added to the BJ_Forget list
1026 * by jbd2_journal_forget, it may no longer be dirty and
1027 * there's no point in keeping a checkpoint record for
1031 * A buffer which has been freed while still being journaled
1032 * by a previous transaction, refile the buffer to BJ_Forget of
1033 * the running transaction. If the just committed transaction
1034 * contains "add to orphan" operation, we can completely
1035 * invalidate the buffer now. We are rather through in that
1036 * since the buffer may be still accessible when blocksize <
1037 * pagesize and it is attached to the last partial page.
1039 if (buffer_freed(bh) && !jh->b_next_transaction) {
1040 struct address_space *mapping;
1042 clear_buffer_freed(bh);
1043 clear_buffer_jbddirty(bh);
1046 * Block device buffers need to stay mapped all the
1047 * time, so it is enough to clear buffer_jbddirty and
1048 * buffer_freed bits. For the file mapping buffers (i.e.
1049 * journalled data) we need to unmap buffer and clear
1050 * more bits. We also need to be careful about the check
1051 * because the data page mapping can get cleared under
1052 * our hands. Note that if mapping == NULL, we don't
1053 * need to make buffer unmapped because the page is
1054 * already detached from the mapping and buffers cannot
1057 mapping = READ_ONCE(bh->b_page->mapping);
1058 if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
1059 clear_buffer_mapped(bh);
1060 clear_buffer_new(bh);
1061 clear_buffer_req(bh);
1066 if (buffer_jbddirty(bh)) {
1067 JBUFFER_TRACE(jh, "add to new checkpointing trans");
1068 __jbd2_journal_insert_checkpoint(jh, commit_transaction);
1069 if (is_journal_aborted(journal))
1070 clear_buffer_jbddirty(bh);
1072 J_ASSERT_BH(bh, !buffer_dirty(bh));
1074 * The buffer on BJ_Forget list and not jbddirty means
1075 * it has been freed by this transaction and hence it
1076 * could not have been reallocated until this
1077 * transaction has committed. *BUT* it could be
1078 * reallocated once we have written all the data to
1079 * disk and before we process the buffer on BJ_Forget
1082 if (!jh->b_next_transaction)
1085 JBUFFER_TRACE(jh, "refile or unfile buffer");
1086 drop_ref = __jbd2_journal_refile_buffer(jh);
1087 spin_unlock(&jh->b_state_lock);
1089 jbd2_journal_put_journal_head(jh);
1091 release_buffer_page(bh); /* Drops bh reference */
1094 cond_resched_lock(&journal->j_list_lock);
1096 spin_unlock(&journal->j_list_lock);
1098 * This is a bit sleazy. We use j_list_lock to protect transition
1099 * of a transaction into T_FINISHED state and calling
1100 * __jbd2_journal_drop_transaction(). Otherwise we could race with
1101 * other checkpointing code processing the transaction...
1103 write_lock(&journal->j_state_lock);
1104 spin_lock(&journal->j_list_lock);
1106 * Now recheck if some buffers did not get attached to the transaction
1107 * while the lock was dropped...
1109 if (commit_transaction->t_forget) {
1110 spin_unlock(&journal->j_list_lock);
1111 write_unlock(&journal->j_state_lock);
1115 /* Add the transaction to the checkpoint list
1116 * __journal_remove_checkpoint() can not destroy transaction
1117 * under us because it is not marked as T_FINISHED yet */
1118 if (journal->j_checkpoint_transactions == NULL) {
1119 journal->j_checkpoint_transactions = commit_transaction;
1120 commit_transaction->t_cpnext = commit_transaction;
1121 commit_transaction->t_cpprev = commit_transaction;
1123 commit_transaction->t_cpnext =
1124 journal->j_checkpoint_transactions;
1125 commit_transaction->t_cpprev =
1126 commit_transaction->t_cpnext->t_cpprev;
1127 commit_transaction->t_cpnext->t_cpprev =
1129 commit_transaction->t_cpprev->t_cpnext =
1132 spin_unlock(&journal->j_list_lock);
1134 /* Done with this transaction! */
1136 jbd_debug(3, "JBD2: commit phase 7\n");
1138 J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
1140 commit_transaction->t_start = jiffies;
1141 stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
1142 commit_transaction->t_start);
1145 * File the transaction statistics
1147 stats.ts_tid = commit_transaction->t_tid;
1148 stats.run.rs_handle_count =
1149 atomic_read(&commit_transaction->t_handle_count);
1150 trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
1151 commit_transaction->t_tid, &stats.run);
1152 stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
1154 commit_transaction->t_state = T_COMMIT_CALLBACK;
1155 J_ASSERT(commit_transaction == journal->j_committing_transaction);
1156 journal->j_commit_sequence = commit_transaction->t_tid;
1157 journal->j_committing_transaction = NULL;
1158 commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
1161 * weight the commit time higher than the average time so we don't
1162 * react too strongly to vast changes in the commit time
1164 if (likely(journal->j_average_commit_time))
1165 journal->j_average_commit_time = (commit_time +
1166 journal->j_average_commit_time*3) / 4;
1168 journal->j_average_commit_time = commit_time;
1170 write_unlock(&journal->j_state_lock);
1172 if (journal->j_commit_callback)
1173 journal->j_commit_callback(journal, commit_transaction);
1174 if (journal->j_fc_cleanup_callback)
1175 journal->j_fc_cleanup_callback(journal, 1);
1177 trace_jbd2_end_commit(journal, commit_transaction);
1178 jbd_debug(1, "JBD2: commit %d complete, head %d\n",
1179 journal->j_commit_sequence, journal->j_tail_sequence);
1181 write_lock(&journal->j_state_lock);
1182 journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
1183 journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
1184 spin_lock(&journal->j_list_lock);
1185 commit_transaction->t_state = T_FINISHED;
1186 /* Check if the transaction can be dropped now that we are finished */
1187 if (commit_transaction->t_checkpoint_list == NULL &&
1188 commit_transaction->t_checkpoint_io_list == NULL) {
1189 __jbd2_journal_drop_transaction(journal, commit_transaction);
1190 jbd2_journal_free_transaction(commit_transaction);
1192 spin_unlock(&journal->j_list_lock);
1193 write_unlock(&journal->j_state_lock);
1194 wake_up(&journal->j_wait_done_commit);
1195 wake_up(&journal->j_fc_wait);
1198 * Calculate overall stats
1200 spin_lock(&journal->j_history_lock);
1201 journal->j_stats.ts_tid++;
1202 journal->j_stats.ts_requested += stats.ts_requested;
1203 journal->j_stats.run.rs_wait += stats.run.rs_wait;
1204 journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
1205 journal->j_stats.run.rs_running += stats.run.rs_running;
1206 journal->j_stats.run.rs_locked += stats.run.rs_locked;
1207 journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
1208 journal->j_stats.run.rs_logging += stats.run.rs_logging;
1209 journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
1210 journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
1211 journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
1212 spin_unlock(&journal->j_history_lock);