1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2007 Oracle. All rights reserved.
7 #include <linux/slab.h>
8 #include <linux/sched.h>
9 #include <linux/sched/mm.h>
10 #include <linux/writeback.h>
11 #include <linux/pagemap.h>
12 #include <linux/blkdev.h>
13 #include <linux/uuid.h>
14 #include <linux/timekeeping.h>
18 #include "transaction.h"
22 #include "dev-replace.h"
24 #include "block-group.h"
25 #include "space-info.h"
28 #include "accessors.h"
29 #include "extent-tree.h"
30 #include "root-tree.h"
33 #include "uuid-tree.h"
35 #include "relocation.h"
38 static struct kmem_cache *btrfs_trans_handle_cachep;
41 * Transaction states and transitions
43 * No running transaction (fs tree blocks are not modified)
46 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
48 * Transaction N [[TRANS_STATE_RUNNING]]
50 * | New trans handles can be attached to transaction N by calling all
51 * | start_transaction() variants.
54 * | Call btrfs_commit_transaction() on any trans handle attached to
57 * Transaction N [[TRANS_STATE_COMMIT_PREP]]
59 * | If there are simultaneous calls to btrfs_commit_transaction() one will win
60 * | the race and the rest will wait for the winner to commit the transaction.
62 * | The winner will wait for previous running transaction to completely finish
65 * Transaction N [[TRANS_STATE_COMMIT_START]]
67 * | Then one of the following happens:
68 * | - Wait for all other trans handle holders to release.
69 * | The btrfs_commit_transaction() caller will do the commit work.
70 * | - Wait for current transaction to be committed by others.
71 * | Other btrfs_commit_transaction() caller will do the commit work.
73 * | At this stage, only btrfs_join_transaction*() variants can attach
74 * | to this running transaction.
75 * | All other variants will wait for current one to finish and attach to
79 * | Caller is chosen to commit transaction N, and all other trans handle
80 * | haven been released.
82 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
84 * | The heavy lifting transaction work is started.
85 * | From running delayed refs (modifying extent tree) to creating pending
86 * | snapshots, running qgroups.
87 * | In short, modify supporting trees to reflect modifications of subvolume
90 * | At this stage, all start_transaction() calls will wait for this
91 * | transaction to finish and attach to transaction N+1.
94 * | Until all supporting trees are updated.
96 * Transaction N [[TRANS_STATE_UNBLOCKED]]
98 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
99 * | need to write them back to disk and update |
102 * | At this stage, new transaction is allowed to |
104 * | All new start_transaction() calls will be |
105 * | attached to transid N+1. |
108 * | Until all tree blocks are super blocks are |
109 * | written to block devices |
111 * Transaction N [[TRANS_STATE_COMPLETED]] V
112 * All tree blocks and super blocks are written. Transaction N+1
113 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
114 * data structures will be cleaned up. | Life goes on
116 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
117 [TRANS_STATE_RUNNING] = 0U,
118 [TRANS_STATE_COMMIT_PREP] = 0U,
119 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
120 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
123 __TRANS_JOIN_NOSTART),
124 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
127 __TRANS_JOIN_NOLOCK |
128 __TRANS_JOIN_NOSTART),
129 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
132 __TRANS_JOIN_NOLOCK |
133 __TRANS_JOIN_NOSTART),
134 [TRANS_STATE_COMPLETED] = (__TRANS_START |
137 __TRANS_JOIN_NOLOCK |
138 __TRANS_JOIN_NOSTART),
141 void btrfs_put_transaction(struct btrfs_transaction *transaction)
143 WARN_ON(refcount_read(&transaction->use_count) == 0);
144 if (refcount_dec_and_test(&transaction->use_count)) {
145 BUG_ON(!list_empty(&transaction->list));
146 WARN_ON(!RB_EMPTY_ROOT(
147 &transaction->delayed_refs.href_root.rb_root));
148 WARN_ON(!RB_EMPTY_ROOT(
149 &transaction->delayed_refs.dirty_extent_root));
150 if (transaction->delayed_refs.pending_csums)
151 btrfs_err(transaction->fs_info,
152 "pending csums is %llu",
153 transaction->delayed_refs.pending_csums);
155 * If any block groups are found in ->deleted_bgs then it's
156 * because the transaction was aborted and a commit did not
157 * happen (things failed before writing the new superblock
158 * and calling btrfs_finish_extent_commit()), so we can not
159 * discard the physical locations of the block groups.
161 while (!list_empty(&transaction->deleted_bgs)) {
162 struct btrfs_block_group *cache;
164 cache = list_first_entry(&transaction->deleted_bgs,
165 struct btrfs_block_group,
167 list_del_init(&cache->bg_list);
168 btrfs_unfreeze_block_group(cache);
169 btrfs_put_block_group(cache);
171 WARN_ON(!list_empty(&transaction->dev_update_list));
176 static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
178 struct btrfs_transaction *cur_trans = trans->transaction;
179 struct btrfs_fs_info *fs_info = trans->fs_info;
180 struct btrfs_root *root, *tmp;
183 * At this point no one can be using this transaction to modify any tree
184 * and no one can start another transaction to modify any tree either.
186 ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
188 down_write(&fs_info->commit_root_sem);
190 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
191 fs_info->last_reloc_trans = trans->transid;
193 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
195 list_del_init(&root->dirty_list);
196 free_extent_buffer(root->commit_root);
197 root->commit_root = btrfs_root_node(root);
198 extent_io_tree_release(&root->dirty_log_pages);
199 btrfs_qgroup_clean_swapped_blocks(root);
202 /* We can free old roots now. */
203 spin_lock(&cur_trans->dropped_roots_lock);
204 while (!list_empty(&cur_trans->dropped_roots)) {
205 root = list_first_entry(&cur_trans->dropped_roots,
206 struct btrfs_root, root_list);
207 list_del_init(&root->root_list);
208 spin_unlock(&cur_trans->dropped_roots_lock);
209 btrfs_free_log(trans, root);
210 btrfs_drop_and_free_fs_root(fs_info, root);
211 spin_lock(&cur_trans->dropped_roots_lock);
213 spin_unlock(&cur_trans->dropped_roots_lock);
215 up_write(&fs_info->commit_root_sem);
218 static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
221 if (type & TRANS_EXTWRITERS)
222 atomic_inc(&trans->num_extwriters);
225 static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
228 if (type & TRANS_EXTWRITERS)
229 atomic_dec(&trans->num_extwriters);
232 static inline void extwriter_counter_init(struct btrfs_transaction *trans,
235 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
238 static inline int extwriter_counter_read(struct btrfs_transaction *trans)
240 return atomic_read(&trans->num_extwriters);
244 * To be called after doing the chunk btree updates right after allocating a new
245 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
246 * chunk after all chunk btree updates and after finishing the second phase of
247 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
248 * group had its chunk item insertion delayed to the second phase.
250 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
252 struct btrfs_fs_info *fs_info = trans->fs_info;
254 if (!trans->chunk_bytes_reserved)
257 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
258 trans->chunk_bytes_reserved, NULL);
259 trans->chunk_bytes_reserved = 0;
263 * either allocate a new transaction or hop into the existing one
265 static noinline int join_transaction(struct btrfs_fs_info *fs_info,
268 struct btrfs_transaction *cur_trans;
270 spin_lock(&fs_info->trans_lock);
272 /* The file system has been taken offline. No new transactions. */
273 if (BTRFS_FS_ERROR(fs_info)) {
274 spin_unlock(&fs_info->trans_lock);
278 cur_trans = fs_info->running_transaction;
280 if (TRANS_ABORTED(cur_trans)) {
281 spin_unlock(&fs_info->trans_lock);
282 return cur_trans->aborted;
284 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
285 spin_unlock(&fs_info->trans_lock);
288 refcount_inc(&cur_trans->use_count);
289 atomic_inc(&cur_trans->num_writers);
290 extwriter_counter_inc(cur_trans, type);
291 spin_unlock(&fs_info->trans_lock);
292 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
293 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
296 spin_unlock(&fs_info->trans_lock);
299 * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the
300 * current transaction, and commit it. If there is no transaction, just
303 if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART)
307 * JOIN_NOLOCK only happens during the transaction commit, so
308 * it is impossible that ->running_transaction is NULL
310 BUG_ON(type == TRANS_JOIN_NOLOCK);
312 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
316 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
317 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
319 spin_lock(&fs_info->trans_lock);
320 if (fs_info->running_transaction) {
322 * someone started a transaction after we unlocked. Make sure
323 * to redo the checks above
325 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
326 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
329 } else if (BTRFS_FS_ERROR(fs_info)) {
330 spin_unlock(&fs_info->trans_lock);
331 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
332 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
337 cur_trans->fs_info = fs_info;
338 atomic_set(&cur_trans->pending_ordered, 0);
339 init_waitqueue_head(&cur_trans->pending_wait);
340 atomic_set(&cur_trans->num_writers, 1);
341 extwriter_counter_init(cur_trans, type);
342 init_waitqueue_head(&cur_trans->writer_wait);
343 init_waitqueue_head(&cur_trans->commit_wait);
344 cur_trans->state = TRANS_STATE_RUNNING;
346 * One for this trans handle, one so it will live on until we
347 * commit the transaction.
349 refcount_set(&cur_trans->use_count, 2);
350 cur_trans->flags = 0;
351 cur_trans->start_time = ktime_get_seconds();
353 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
355 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
356 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
357 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
360 * although the tree mod log is per file system and not per transaction,
361 * the log must never go across transaction boundaries.
364 if (!list_empty(&fs_info->tree_mod_seq_list))
365 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
366 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
367 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
368 atomic64_set(&fs_info->tree_mod_seq, 0);
370 spin_lock_init(&cur_trans->delayed_refs.lock);
372 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
373 INIT_LIST_HEAD(&cur_trans->dev_update_list);
374 INIT_LIST_HEAD(&cur_trans->switch_commits);
375 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
376 INIT_LIST_HEAD(&cur_trans->io_bgs);
377 INIT_LIST_HEAD(&cur_trans->dropped_roots);
378 mutex_init(&cur_trans->cache_write_mutex);
379 spin_lock_init(&cur_trans->dirty_bgs_lock);
380 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
381 spin_lock_init(&cur_trans->dropped_roots_lock);
382 list_add_tail(&cur_trans->list, &fs_info->trans_list);
383 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
384 IO_TREE_TRANS_DIRTY_PAGES);
385 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
386 IO_TREE_FS_PINNED_EXTENTS);
387 btrfs_set_fs_generation(fs_info, fs_info->generation + 1);
388 cur_trans->transid = fs_info->generation;
389 fs_info->running_transaction = cur_trans;
390 cur_trans->aborted = 0;
391 spin_unlock(&fs_info->trans_lock);
397 * This does all the record keeping required to make sure that a shareable root
398 * is properly recorded in a given transaction. This is required to make sure
399 * the old root from before we joined the transaction is deleted when the
400 * transaction commits.
402 static int record_root_in_trans(struct btrfs_trans_handle *trans,
403 struct btrfs_root *root,
406 struct btrfs_fs_info *fs_info = root->fs_info;
409 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
410 root->last_trans < trans->transid) || force) {
411 WARN_ON(!force && root->commit_root != root->node);
414 * see below for IN_TRANS_SETUP usage rules
415 * we have the reloc mutex held now, so there
416 * is only one writer in this function
418 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
420 /* make sure readers find IN_TRANS_SETUP before
421 * they find our root->last_trans update
425 spin_lock(&fs_info->fs_roots_radix_lock);
426 if (root->last_trans == trans->transid && !force) {
427 spin_unlock(&fs_info->fs_roots_radix_lock);
430 radix_tree_tag_set(&fs_info->fs_roots_radix,
431 (unsigned long)root->root_key.objectid,
432 BTRFS_ROOT_TRANS_TAG);
433 spin_unlock(&fs_info->fs_roots_radix_lock);
434 root->last_trans = trans->transid;
436 /* this is pretty tricky. We don't want to
437 * take the relocation lock in btrfs_record_root_in_trans
438 * unless we're really doing the first setup for this root in
441 * Normally we'd use root->last_trans as a flag to decide
442 * if we want to take the expensive mutex.
444 * But, we have to set root->last_trans before we
445 * init the relocation root, otherwise, we trip over warnings
446 * in ctree.c. The solution used here is to flag ourselves
447 * with root IN_TRANS_SETUP. When this is 1, we're still
448 * fixing up the reloc trees and everyone must wait.
450 * When this is zero, they can trust root->last_trans and fly
451 * through btrfs_record_root_in_trans without having to take the
452 * lock. smp_wmb() makes sure that all the writes above are
453 * done before we pop in the zero below
455 ret = btrfs_init_reloc_root(trans, root);
456 smp_mb__before_atomic();
457 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
463 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
464 struct btrfs_root *root)
466 struct btrfs_fs_info *fs_info = root->fs_info;
467 struct btrfs_transaction *cur_trans = trans->transaction;
469 /* Add ourselves to the transaction dropped list */
470 spin_lock(&cur_trans->dropped_roots_lock);
471 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
472 spin_unlock(&cur_trans->dropped_roots_lock);
474 /* Make sure we don't try to update the root at commit time */
475 spin_lock(&fs_info->fs_roots_radix_lock);
476 radix_tree_tag_clear(&fs_info->fs_roots_radix,
477 (unsigned long)root->root_key.objectid,
478 BTRFS_ROOT_TRANS_TAG);
479 spin_unlock(&fs_info->fs_roots_radix_lock);
482 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
483 struct btrfs_root *root)
485 struct btrfs_fs_info *fs_info = root->fs_info;
488 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
492 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
496 if (root->last_trans == trans->transid &&
497 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
500 mutex_lock(&fs_info->reloc_mutex);
501 ret = record_root_in_trans(trans, root, 0);
502 mutex_unlock(&fs_info->reloc_mutex);
507 static inline int is_transaction_blocked(struct btrfs_transaction *trans)
509 return (trans->state >= TRANS_STATE_COMMIT_START &&
510 trans->state < TRANS_STATE_UNBLOCKED &&
511 !TRANS_ABORTED(trans));
514 /* wait for commit against the current transaction to become unblocked
515 * when this is done, it is safe to start a new transaction, but the current
516 * transaction might not be fully on disk.
518 static void wait_current_trans(struct btrfs_fs_info *fs_info)
520 struct btrfs_transaction *cur_trans;
522 spin_lock(&fs_info->trans_lock);
523 cur_trans = fs_info->running_transaction;
524 if (cur_trans && is_transaction_blocked(cur_trans)) {
525 refcount_inc(&cur_trans->use_count);
526 spin_unlock(&fs_info->trans_lock);
528 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
529 wait_event(fs_info->transaction_wait,
530 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
531 TRANS_ABORTED(cur_trans));
532 btrfs_put_transaction(cur_trans);
534 spin_unlock(&fs_info->trans_lock);
538 static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
540 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
543 if (type == TRANS_START)
549 static inline bool need_reserve_reloc_root(struct btrfs_root *root)
551 struct btrfs_fs_info *fs_info = root->fs_info;
553 if (!fs_info->reloc_ctl ||
554 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
555 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
562 static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info,
563 enum btrfs_reserve_flush_enum flush,
565 u64 *delayed_refs_bytes)
567 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
568 struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info;
569 u64 extra_delayed_refs_bytes = 0;
574 * If there's a gap between the size of the delayed refs reserve and
575 * its reserved space, than some tasks have added delayed refs or bumped
576 * its size otherwise (due to block group creation or removal, or block
577 * group item update). Also try to allocate that gap in order to prevent
578 * using (and possibly abusing) the global reserve when committing the
581 if (flush == BTRFS_RESERVE_FLUSH_ALL &&
582 !btrfs_block_rsv_full(delayed_refs_rsv)) {
583 spin_lock(&delayed_refs_rsv->lock);
584 if (delayed_refs_rsv->size > delayed_refs_rsv->reserved)
585 extra_delayed_refs_bytes = delayed_refs_rsv->size -
586 delayed_refs_rsv->reserved;
587 spin_unlock(&delayed_refs_rsv->lock);
590 bytes = num_bytes + *delayed_refs_bytes + extra_delayed_refs_bytes;
593 * We want to reserve all the bytes we may need all at once, so we only
594 * do 1 enospc flushing cycle per transaction start.
596 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
598 if (extra_delayed_refs_bytes > 0)
599 btrfs_migrate_to_delayed_refs_rsv(fs_info,
600 extra_delayed_refs_bytes);
604 if (extra_delayed_refs_bytes > 0) {
605 bytes -= extra_delayed_refs_bytes;
606 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
612 * If we are an emergency flush, which can steal from the global block
613 * reserve, then attempt to not reserve space for the delayed refs, as
614 * we will consume space for them from the global block reserve.
616 if (flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
617 bytes -= *delayed_refs_bytes;
618 *delayed_refs_bytes = 0;
619 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
625 static struct btrfs_trans_handle *
626 start_transaction(struct btrfs_root *root, unsigned int num_items,
627 unsigned int type, enum btrfs_reserve_flush_enum flush,
628 bool enforce_qgroups)
630 struct btrfs_fs_info *fs_info = root->fs_info;
631 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
632 struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
633 struct btrfs_trans_handle *h;
634 struct btrfs_transaction *cur_trans;
636 u64 qgroup_reserved = 0;
637 u64 delayed_refs_bytes = 0;
638 bool reloc_reserved = false;
639 bool do_chunk_alloc = false;
642 if (BTRFS_FS_ERROR(fs_info))
643 return ERR_PTR(-EROFS);
645 if (current->journal_info) {
646 WARN_ON(type & TRANS_EXTWRITERS);
647 h = current->journal_info;
648 refcount_inc(&h->use_count);
649 WARN_ON(refcount_read(&h->use_count) > 2);
650 h->orig_rsv = h->block_rsv;
656 * Do the reservation before we join the transaction so we can do all
657 * the appropriate flushing if need be.
659 if (num_items && root != fs_info->chunk_root) {
660 qgroup_reserved = num_items * fs_info->nodesize;
662 * Use prealloc for now, as there might be a currently running
663 * transaction that could free this reserved space prematurely
666 ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved,
667 enforce_qgroups, false);
671 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
673 * If we plan to insert/update/delete "num_items" from a btree,
674 * we will also generate delayed refs for extent buffers in the
675 * respective btree paths, so reserve space for the delayed refs
676 * that will be generated by the caller as it modifies btrees.
677 * Try to reserve them to avoid excessive use of the global
680 delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items);
683 * Do the reservation for the relocation root creation
685 if (need_reserve_reloc_root(root)) {
686 num_bytes += fs_info->nodesize;
687 reloc_reserved = true;
690 ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes,
691 &delayed_refs_bytes);
695 btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true);
697 if (trans_rsv->space_info->force_alloc)
698 do_chunk_alloc = true;
699 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
700 !btrfs_block_rsv_full(delayed_refs_rsv)) {
702 * Some people call with btrfs_start_transaction(root, 0)
703 * because they can be throttled, but have some other mechanism
704 * for reserving space. We still want these guys to refill the
705 * delayed block_rsv so just add 1 items worth of reservation
708 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
713 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
720 * If we are JOIN_NOLOCK we're already committing a transaction and
721 * waiting on this guy, so we don't need to do the sb_start_intwrite
722 * because we're already holding a ref. We need this because we could
723 * have raced in and did an fsync() on a file which can kick a commit
724 * and then we deadlock with somebody doing a freeze.
726 * If we are ATTACH, it means we just want to catch the current
727 * transaction and commit it, so we needn't do sb_start_intwrite().
729 if (type & __TRANS_FREEZABLE)
730 sb_start_intwrite(fs_info->sb);
732 if (may_wait_transaction(fs_info, type))
733 wait_current_trans(fs_info);
736 ret = join_transaction(fs_info, type);
738 wait_current_trans(fs_info);
739 if (unlikely(type == TRANS_ATTACH ||
740 type == TRANS_JOIN_NOSTART))
743 } while (ret == -EBUSY);
748 cur_trans = fs_info->running_transaction;
750 h->transid = cur_trans->transid;
751 h->transaction = cur_trans;
752 refcount_set(&h->use_count, 1);
753 h->fs_info = root->fs_info;
756 INIT_LIST_HEAD(&h->new_bgs);
757 btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS);
760 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
761 may_wait_transaction(fs_info, type)) {
762 current->journal_info = h;
763 btrfs_commit_transaction(h);
768 trace_btrfs_space_reservation(fs_info, "transaction",
769 h->transid, num_bytes, 1);
770 h->block_rsv = trans_rsv;
771 h->bytes_reserved = num_bytes;
772 if (delayed_refs_bytes > 0) {
773 trace_btrfs_space_reservation(fs_info,
774 "local_delayed_refs_rsv",
776 delayed_refs_bytes, 1);
777 h->delayed_refs_bytes_reserved = delayed_refs_bytes;
778 btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true);
779 delayed_refs_bytes = 0;
781 h->reloc_reserved = reloc_reserved;
785 * Now that we have found a transaction to be a part of, convert the
786 * qgroup reservation from prealloc to pertrans. A different transaction
787 * can't race in and free our pertrans out from under us.
790 btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
793 if (!current->journal_info)
794 current->journal_info = h;
797 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
798 * ALLOC_FORCE the first run through, and then we won't allocate for
799 * anybody else who races in later. We don't care about the return
802 if (do_chunk_alloc && num_bytes) {
803 u64 flags = h->block_rsv->space_info->flags;
805 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
806 CHUNK_ALLOC_NO_FORCE);
810 * btrfs_record_root_in_trans() needs to alloc new extents, and may
811 * call btrfs_join_transaction() while we're also starting a
814 * Thus it need to be called after current->journal_info initialized,
815 * or we can deadlock.
817 ret = btrfs_record_root_in_trans(h, root);
820 * The transaction handle is fully initialized and linked with
821 * other structures so it needs to be ended in case of errors,
824 btrfs_end_transaction(h);
831 if (type & __TRANS_FREEZABLE)
832 sb_end_intwrite(fs_info->sb);
833 kmem_cache_free(btrfs_trans_handle_cachep, h);
836 btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL);
837 if (delayed_refs_bytes)
838 btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info,
841 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
845 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
846 unsigned int num_items)
848 return start_transaction(root, num_items, TRANS_START,
849 BTRFS_RESERVE_FLUSH_ALL, true);
852 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
853 struct btrfs_root *root,
854 unsigned int num_items)
856 return start_transaction(root, num_items, TRANS_START,
857 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
860 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
862 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
866 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
868 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
869 BTRFS_RESERVE_NO_FLUSH, true);
873 * Similar to regular join but it never starts a transaction when none is
874 * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED.
875 * This is similar to btrfs_attach_transaction() but it allows the join to
876 * happen if the transaction commit already started but it's not yet in the
877 * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING).
879 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
881 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
882 BTRFS_RESERVE_NO_FLUSH, true);
886 * Catch the running transaction.
888 * It is used when we want to commit the current the transaction, but
889 * don't want to start a new one.
891 * Note: If this function return -ENOENT, it just means there is no
892 * running transaction. But it is possible that the inactive transaction
893 * is still in the memory, not fully on disk. If you hope there is no
894 * inactive transaction in the fs when -ENOENT is returned, you should
896 * btrfs_attach_transaction_barrier()
898 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
900 return start_transaction(root, 0, TRANS_ATTACH,
901 BTRFS_RESERVE_NO_FLUSH, true);
905 * Catch the running transaction.
907 * It is similar to the above function, the difference is this one
908 * will wait for all the inactive transactions until they fully
911 struct btrfs_trans_handle *
912 btrfs_attach_transaction_barrier(struct btrfs_root *root)
914 struct btrfs_trans_handle *trans;
916 trans = start_transaction(root, 0, TRANS_ATTACH,
917 BTRFS_RESERVE_NO_FLUSH, true);
918 if (trans == ERR_PTR(-ENOENT)) {
921 ret = btrfs_wait_for_commit(root->fs_info, 0);
929 /* Wait for a transaction commit to reach at least the given state. */
930 static noinline void wait_for_commit(struct btrfs_transaction *commit,
931 const enum btrfs_trans_state min_state)
933 struct btrfs_fs_info *fs_info = commit->fs_info;
934 u64 transid = commit->transid;
938 * At the moment this function is called with min_state either being
939 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
941 if (min_state == TRANS_STATE_COMPLETED)
942 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
944 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
947 wait_event(commit->commit_wait, commit->state >= min_state);
949 btrfs_put_transaction(commit);
951 if (min_state < TRANS_STATE_COMPLETED)
955 * A transaction isn't really completed until all of the
956 * previous transactions are completed, but with fsync we can
957 * end up with SUPER_COMMITTED transactions before a COMPLETED
958 * transaction. Wait for those.
961 spin_lock(&fs_info->trans_lock);
962 commit = list_first_entry_or_null(&fs_info->trans_list,
963 struct btrfs_transaction,
965 if (!commit || commit->transid > transid) {
966 spin_unlock(&fs_info->trans_lock);
969 refcount_inc(&commit->use_count);
971 spin_unlock(&fs_info->trans_lock);
975 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
977 struct btrfs_transaction *cur_trans = NULL, *t;
981 if (transid <= btrfs_get_last_trans_committed(fs_info))
984 /* find specified transaction */
985 spin_lock(&fs_info->trans_lock);
986 list_for_each_entry(t, &fs_info->trans_list, list) {
987 if (t->transid == transid) {
989 refcount_inc(&cur_trans->use_count);
993 if (t->transid > transid) {
998 spin_unlock(&fs_info->trans_lock);
1001 * The specified transaction doesn't exist, or we
1002 * raced with btrfs_commit_transaction
1005 if (transid > btrfs_get_last_trans_committed(fs_info))
1010 /* find newest transaction that is committing | committed */
1011 spin_lock(&fs_info->trans_lock);
1012 list_for_each_entry_reverse(t, &fs_info->trans_list,
1014 if (t->state >= TRANS_STATE_COMMIT_START) {
1015 if (t->state == TRANS_STATE_COMPLETED)
1018 refcount_inc(&cur_trans->use_count);
1022 spin_unlock(&fs_info->trans_lock);
1024 goto out; /* nothing committing|committed */
1027 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
1028 ret = cur_trans->aborted;
1029 btrfs_put_transaction(cur_trans);
1034 void btrfs_throttle(struct btrfs_fs_info *fs_info)
1036 wait_current_trans(fs_info);
1039 bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
1041 struct btrfs_transaction *cur_trans = trans->transaction;
1043 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
1044 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
1047 if (btrfs_check_space_for_delayed_refs(trans->fs_info))
1050 return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
1053 static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
1056 struct btrfs_fs_info *fs_info = trans->fs_info;
1058 if (!trans->block_rsv) {
1059 ASSERT(!trans->bytes_reserved);
1060 ASSERT(!trans->delayed_refs_bytes_reserved);
1064 if (!trans->bytes_reserved) {
1065 ASSERT(!trans->delayed_refs_bytes_reserved);
1069 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
1070 trace_btrfs_space_reservation(fs_info, "transaction",
1071 trans->transid, trans->bytes_reserved, 0);
1072 btrfs_block_rsv_release(fs_info, trans->block_rsv,
1073 trans->bytes_reserved, NULL);
1074 trans->bytes_reserved = 0;
1076 if (!trans->delayed_refs_bytes_reserved)
1079 trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv",
1081 trans->delayed_refs_bytes_reserved, 0);
1082 btrfs_block_rsv_release(fs_info, &trans->delayed_rsv,
1083 trans->delayed_refs_bytes_reserved, NULL);
1084 trans->delayed_refs_bytes_reserved = 0;
1087 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
1090 struct btrfs_fs_info *info = trans->fs_info;
1091 struct btrfs_transaction *cur_trans = trans->transaction;
1094 if (refcount_read(&trans->use_count) > 1) {
1095 refcount_dec(&trans->use_count);
1096 trans->block_rsv = trans->orig_rsv;
1100 btrfs_trans_release_metadata(trans);
1101 trans->block_rsv = NULL;
1103 btrfs_create_pending_block_groups(trans);
1105 btrfs_trans_release_chunk_metadata(trans);
1107 if (trans->type & __TRANS_FREEZABLE)
1108 sb_end_intwrite(info->sb);
1110 WARN_ON(cur_trans != info->running_transaction);
1111 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1112 atomic_dec(&cur_trans->num_writers);
1113 extwriter_counter_dec(cur_trans, trans->type);
1115 cond_wake_up(&cur_trans->writer_wait);
1117 btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1118 btrfs_lockdep_release(info, btrfs_trans_num_writers);
1120 btrfs_put_transaction(cur_trans);
1122 if (current->journal_info == trans)
1123 current->journal_info = NULL;
1126 btrfs_run_delayed_iputs(info);
1128 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1129 wake_up_process(info->transaction_kthread);
1130 if (TRANS_ABORTED(trans))
1131 err = trans->aborted;
1136 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1140 int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1142 return __btrfs_end_transaction(trans, 0);
1145 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1147 return __btrfs_end_transaction(trans, 1);
1151 * when btree blocks are allocated, they have some corresponding bits set for
1152 * them in one of two extent_io trees. This is used to make sure all of
1153 * those extents are sent to disk but does not wait on them
1155 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1156 struct extent_io_tree *dirty_pages, int mark)
1160 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1161 struct extent_state *cached_state = NULL;
1165 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1166 mark, &cached_state)) {
1167 bool wait_writeback = false;
1169 err = convert_extent_bit(dirty_pages, start, end,
1171 mark, &cached_state);
1173 * convert_extent_bit can return -ENOMEM, which is most of the
1174 * time a temporary error. So when it happens, ignore the error
1175 * and wait for writeback of this range to finish - because we
1176 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1177 * to __btrfs_wait_marked_extents() would not know that
1178 * writeback for this range started and therefore wouldn't
1179 * wait for it to finish - we don't want to commit a
1180 * superblock that points to btree nodes/leafs for which
1181 * writeback hasn't finished yet (and without errors).
1182 * We cleanup any entries left in the io tree when committing
1183 * the transaction (through extent_io_tree_release()).
1185 if (err == -ENOMEM) {
1187 wait_writeback = true;
1190 err = filemap_fdatawrite_range(mapping, start, end);
1193 else if (wait_writeback)
1194 werr = filemap_fdatawait_range(mapping, start, end);
1195 free_extent_state(cached_state);
1196 cached_state = NULL;
1204 * when btree blocks are allocated, they have some corresponding bits set for
1205 * them in one of two extent_io trees. This is used to make sure all of
1206 * those extents are on disk for transaction or log commit. We wait
1207 * on all the pages and clear them from the dirty pages state tree
1209 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1210 struct extent_io_tree *dirty_pages)
1214 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1215 struct extent_state *cached_state = NULL;
1219 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1220 EXTENT_NEED_WAIT, &cached_state)) {
1222 * Ignore -ENOMEM errors returned by clear_extent_bit().
1223 * When committing the transaction, we'll remove any entries
1224 * left in the io tree. For a log commit, we don't remove them
1225 * after committing the log because the tree can be accessed
1226 * concurrently - we do it only at transaction commit time when
1227 * it's safe to do it (through extent_io_tree_release()).
1229 err = clear_extent_bit(dirty_pages, start, end,
1230 EXTENT_NEED_WAIT, &cached_state);
1234 err = filemap_fdatawait_range(mapping, start, end);
1237 free_extent_state(cached_state);
1238 cached_state = NULL;
1247 static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1248 struct extent_io_tree *dirty_pages)
1250 bool errors = false;
1253 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1254 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1262 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1264 struct btrfs_fs_info *fs_info = log_root->fs_info;
1265 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1266 bool errors = false;
1269 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1271 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1272 if ((mark & EXTENT_DIRTY) &&
1273 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1276 if ((mark & EXTENT_NEW) &&
1277 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1286 * When btree blocks are allocated the corresponding extents are marked dirty.
1287 * This function ensures such extents are persisted on disk for transaction or
1290 * @trans: transaction whose dirty pages we'd like to write
1292 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1296 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1297 struct btrfs_fs_info *fs_info = trans->fs_info;
1298 struct blk_plug plug;
1300 blk_start_plug(&plug);
1301 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1302 blk_finish_plug(&plug);
1303 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1305 extent_io_tree_release(&trans->transaction->dirty_pages);
1316 * this is used to update the root pointer in the tree of tree roots.
1318 * But, in the case of the extent allocation tree, updating the root
1319 * pointer may allocate blocks which may change the root of the extent
1322 * So, this loops and repeats and makes sure the cowonly root didn't
1323 * change while the root pointer was being updated in the metadata.
1325 static int update_cowonly_root(struct btrfs_trans_handle *trans,
1326 struct btrfs_root *root)
1329 u64 old_root_bytenr;
1331 struct btrfs_fs_info *fs_info = root->fs_info;
1332 struct btrfs_root *tree_root = fs_info->tree_root;
1334 old_root_used = btrfs_root_used(&root->root_item);
1337 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1338 if (old_root_bytenr == root->node->start &&
1339 old_root_used == btrfs_root_used(&root->root_item))
1342 btrfs_set_root_node(&root->root_item, root->node);
1343 ret = btrfs_update_root(trans, tree_root,
1349 old_root_used = btrfs_root_used(&root->root_item);
1356 * update all the cowonly tree roots on disk
1358 * The error handling in this function may not be obvious. Any of the
1359 * failures will cause the file system to go offline. We still need
1360 * to clean up the delayed refs.
1362 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1364 struct btrfs_fs_info *fs_info = trans->fs_info;
1365 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1366 struct list_head *io_bgs = &trans->transaction->io_bgs;
1367 struct list_head *next;
1368 struct extent_buffer *eb;
1372 * At this point no one can be using this transaction to modify any tree
1373 * and no one can start another transaction to modify any tree either.
1375 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1377 eb = btrfs_lock_root_node(fs_info->tree_root);
1378 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1379 0, &eb, BTRFS_NESTING_COW);
1380 btrfs_tree_unlock(eb);
1381 free_extent_buffer(eb);
1386 ret = btrfs_run_dev_stats(trans);
1389 ret = btrfs_run_dev_replace(trans);
1392 ret = btrfs_run_qgroups(trans);
1396 ret = btrfs_setup_space_cache(trans);
1401 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1402 struct btrfs_root *root;
1403 next = fs_info->dirty_cowonly_roots.next;
1404 list_del_init(next);
1405 root = list_entry(next, struct btrfs_root, dirty_list);
1406 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1408 list_add_tail(&root->dirty_list,
1409 &trans->transaction->switch_commits);
1410 ret = update_cowonly_root(trans, root);
1415 /* Now flush any delayed refs generated by updating all of the roots */
1416 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1420 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1421 ret = btrfs_write_dirty_block_groups(trans);
1426 * We're writing the dirty block groups, which could generate
1427 * delayed refs, which could generate more dirty block groups,
1428 * so we want to keep this flushing in this loop to make sure
1429 * everything gets run.
1431 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1436 if (!list_empty(&fs_info->dirty_cowonly_roots))
1439 /* Update dev-replace pointer once everything is committed */
1440 fs_info->dev_replace.committed_cursor_left =
1441 fs_info->dev_replace.cursor_left_last_write_of_item;
1447 * If we had a pending drop we need to see if there are any others left in our
1448 * dead roots list, and if not clear our bit and wake any waiters.
1450 void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1453 * We put the drop in progress roots at the front of the list, so if the
1454 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1457 spin_lock(&fs_info->trans_lock);
1458 if (!list_empty(&fs_info->dead_roots)) {
1459 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1462 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1463 spin_unlock(&fs_info->trans_lock);
1467 spin_unlock(&fs_info->trans_lock);
1469 btrfs_wake_unfinished_drop(fs_info);
1473 * dead roots are old snapshots that need to be deleted. This allocates
1474 * a dirty root struct and adds it into the list of dead roots that need to
1477 void btrfs_add_dead_root(struct btrfs_root *root)
1479 struct btrfs_fs_info *fs_info = root->fs_info;
1481 spin_lock(&fs_info->trans_lock);
1482 if (list_empty(&root->root_list)) {
1483 btrfs_grab_root(root);
1485 /* We want to process the partially complete drops first. */
1486 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1487 list_add(&root->root_list, &fs_info->dead_roots);
1489 list_add_tail(&root->root_list, &fs_info->dead_roots);
1491 spin_unlock(&fs_info->trans_lock);
1495 * Update each subvolume root and its relocation root, if it exists, in the tree
1496 * of tree roots. Also free log roots if they exist.
1498 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1500 struct btrfs_fs_info *fs_info = trans->fs_info;
1501 struct btrfs_root *gang[8];
1506 * At this point no one can be using this transaction to modify any tree
1507 * and no one can start another transaction to modify any tree either.
1509 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1511 spin_lock(&fs_info->fs_roots_radix_lock);
1513 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1516 BTRFS_ROOT_TRANS_TAG);
1519 for (i = 0; i < ret; i++) {
1520 struct btrfs_root *root = gang[i];
1524 * At this point we can neither have tasks logging inodes
1525 * from a root nor trying to commit a log tree.
1527 ASSERT(atomic_read(&root->log_writers) == 0);
1528 ASSERT(atomic_read(&root->log_commit[0]) == 0);
1529 ASSERT(atomic_read(&root->log_commit[1]) == 0);
1531 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1532 (unsigned long)root->root_key.objectid,
1533 BTRFS_ROOT_TRANS_TAG);
1534 spin_unlock(&fs_info->fs_roots_radix_lock);
1536 btrfs_free_log(trans, root);
1537 ret2 = btrfs_update_reloc_root(trans, root);
1541 /* see comments in should_cow_block() */
1542 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1543 smp_mb__after_atomic();
1545 if (root->commit_root != root->node) {
1546 list_add_tail(&root->dirty_list,
1547 &trans->transaction->switch_commits);
1548 btrfs_set_root_node(&root->root_item,
1552 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1557 spin_lock(&fs_info->fs_roots_radix_lock);
1558 btrfs_qgroup_free_meta_all_pertrans(root);
1561 spin_unlock(&fs_info->fs_roots_radix_lock);
1566 * Do all special snapshot related qgroup dirty hack.
1568 * Will do all needed qgroup inherit and dirty hack like switch commit
1569 * roots inside one transaction and write all btree into disk, to make
1572 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1573 struct btrfs_root *src,
1574 struct btrfs_root *parent,
1575 struct btrfs_qgroup_inherit *inherit,
1578 struct btrfs_fs_info *fs_info = src->fs_info;
1582 * Save some performance in the case that qgroups are not enabled. If
1583 * this check races with the ioctl, rescan will kick in anyway.
1585 if (!btrfs_qgroup_full_accounting(fs_info))
1589 * Ensure dirty @src will be committed. Or, after coming
1590 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1591 * recorded root will never be updated again, causing an outdated root
1594 ret = record_root_in_trans(trans, src, 1);
1599 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1600 * src root, so we must run the delayed refs here.
1602 * However this isn't particularly fool proof, because there's no
1603 * synchronization keeping us from changing the tree after this point
1604 * before we do the qgroup_inherit, or even from making changes while
1605 * we're doing the qgroup_inherit. But that's a problem for the future,
1606 * for now flush the delayed refs to narrow the race window where the
1607 * qgroup counters could end up wrong.
1609 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1611 btrfs_abort_transaction(trans, ret);
1615 ret = commit_fs_roots(trans);
1618 ret = btrfs_qgroup_account_extents(trans);
1622 /* Now qgroup are all updated, we can inherit it to new qgroups */
1623 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1624 parent->root_key.objectid, inherit);
1629 * Now we do a simplified commit transaction, which will:
1630 * 1) commit all subvolume and extent tree
1631 * To ensure all subvolume and extent tree have a valid
1632 * commit_root to accounting later insert_dir_item()
1633 * 2) write all btree blocks onto disk
1634 * This is to make sure later btree modification will be cowed
1635 * Or commit_root can be populated and cause wrong qgroup numbers
1636 * In this simplified commit, we don't really care about other trees
1637 * like chunk and root tree, as they won't affect qgroup.
1638 * And we don't write super to avoid half committed status.
1640 ret = commit_cowonly_roots(trans);
1643 switch_commit_roots(trans);
1644 ret = btrfs_write_and_wait_transaction(trans);
1646 btrfs_handle_fs_error(fs_info, ret,
1647 "Error while writing out transaction for qgroup");
1651 * Force parent root to be updated, as we recorded it before so its
1652 * last_trans == cur_transid.
1653 * Or it won't be committed again onto disk after later
1657 ret = record_root_in_trans(trans, parent, 1);
1662 * new snapshots need to be created at a very specific time in the
1663 * transaction commit. This does the actual creation.
1666 * If the error which may affect the commitment of the current transaction
1667 * happens, we should return the error number. If the error which just affect
1668 * the creation of the pending snapshots, just return 0.
1670 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1671 struct btrfs_pending_snapshot *pending)
1674 struct btrfs_fs_info *fs_info = trans->fs_info;
1675 struct btrfs_key key;
1676 struct btrfs_root_item *new_root_item;
1677 struct btrfs_root *tree_root = fs_info->tree_root;
1678 struct btrfs_root *root = pending->root;
1679 struct btrfs_root *parent_root;
1680 struct btrfs_block_rsv *rsv;
1681 struct inode *parent_inode = pending->dir;
1682 struct btrfs_path *path;
1683 struct btrfs_dir_item *dir_item;
1684 struct extent_buffer *tmp;
1685 struct extent_buffer *old;
1686 struct timespec64 cur_time;
1692 unsigned int nofs_flags;
1693 struct fscrypt_name fname;
1695 ASSERT(pending->path);
1696 path = pending->path;
1698 ASSERT(pending->root_item);
1699 new_root_item = pending->root_item;
1702 * We're inside a transaction and must make sure that any potential
1703 * allocations with GFP_KERNEL in fscrypt won't recurse back to
1706 nofs_flags = memalloc_nofs_save();
1707 pending->error = fscrypt_setup_filename(parent_inode,
1708 &pending->dentry->d_name, 0,
1710 memalloc_nofs_restore(nofs_flags);
1714 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1719 * Make qgroup to skip current new snapshot's qgroupid, as it is
1720 * accounted by later btrfs_qgroup_inherit().
1722 btrfs_set_skip_qgroup(trans, objectid);
1724 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1726 if (to_reserve > 0) {
1727 pending->error = btrfs_block_rsv_add(fs_info,
1728 &pending->block_rsv,
1730 BTRFS_RESERVE_NO_FLUSH);
1732 goto clear_skip_qgroup;
1735 key.objectid = objectid;
1736 key.offset = (u64)-1;
1737 key.type = BTRFS_ROOT_ITEM_KEY;
1739 rsv = trans->block_rsv;
1740 trans->block_rsv = &pending->block_rsv;
1741 trans->bytes_reserved = trans->block_rsv->reserved;
1742 trace_btrfs_space_reservation(fs_info, "transaction",
1744 trans->bytes_reserved, 1);
1745 parent_root = BTRFS_I(parent_inode)->root;
1746 ret = record_root_in_trans(trans, parent_root, 0);
1749 cur_time = current_time(parent_inode);
1752 * insert the directory item
1754 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1756 btrfs_abort_transaction(trans, ret);
1760 /* check if there is a file/dir which has the same name. */
1761 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1762 btrfs_ino(BTRFS_I(parent_inode)),
1763 &fname.disk_name, 0);
1764 if (dir_item != NULL && !IS_ERR(dir_item)) {
1765 pending->error = -EEXIST;
1766 goto dir_item_existed;
1767 } else if (IS_ERR(dir_item)) {
1768 ret = PTR_ERR(dir_item);
1769 btrfs_abort_transaction(trans, ret);
1772 btrfs_release_path(path);
1774 ret = btrfs_create_qgroup(trans, objectid);
1775 if (ret && ret != -EEXIST) {
1776 btrfs_abort_transaction(trans, ret);
1781 * pull in the delayed directory update
1782 * and the delayed inode item
1783 * otherwise we corrupt the FS during
1786 ret = btrfs_run_delayed_items(trans);
1787 if (ret) { /* Transaction aborted */
1788 btrfs_abort_transaction(trans, ret);
1792 ret = record_root_in_trans(trans, root, 0);
1794 btrfs_abort_transaction(trans, ret);
1797 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1798 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1799 btrfs_check_and_init_root_item(new_root_item);
1801 root_flags = btrfs_root_flags(new_root_item);
1802 if (pending->readonly)
1803 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1805 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1806 btrfs_set_root_flags(new_root_item, root_flags);
1808 btrfs_set_root_generation_v2(new_root_item,
1810 generate_random_guid(new_root_item->uuid);
1811 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1813 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1814 memset(new_root_item->received_uuid, 0,
1815 sizeof(new_root_item->received_uuid));
1816 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1817 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1818 btrfs_set_root_stransid(new_root_item, 0);
1819 btrfs_set_root_rtransid(new_root_item, 0);
1821 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1822 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1823 btrfs_set_root_otransid(new_root_item, trans->transid);
1825 old = btrfs_lock_root_node(root);
1826 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1829 btrfs_tree_unlock(old);
1830 free_extent_buffer(old);
1831 btrfs_abort_transaction(trans, ret);
1835 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1836 /* clean up in any case */
1837 btrfs_tree_unlock(old);
1838 free_extent_buffer(old);
1840 btrfs_abort_transaction(trans, ret);
1843 /* see comments in should_cow_block() */
1844 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1847 btrfs_set_root_node(new_root_item, tmp);
1848 /* record when the snapshot was created in key.offset */
1849 key.offset = trans->transid;
1850 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1851 btrfs_tree_unlock(tmp);
1852 free_extent_buffer(tmp);
1854 btrfs_abort_transaction(trans, ret);
1859 * insert root back/forward references
1861 ret = btrfs_add_root_ref(trans, objectid,
1862 parent_root->root_key.objectid,
1863 btrfs_ino(BTRFS_I(parent_inode)), index,
1866 btrfs_abort_transaction(trans, ret);
1870 key.offset = (u64)-1;
1871 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1872 if (IS_ERR(pending->snap)) {
1873 ret = PTR_ERR(pending->snap);
1874 pending->snap = NULL;
1875 btrfs_abort_transaction(trans, ret);
1879 ret = btrfs_reloc_post_snapshot(trans, pending);
1881 btrfs_abort_transaction(trans, ret);
1886 * Do special qgroup accounting for snapshot, as we do some qgroup
1887 * snapshot hack to do fast snapshot.
1888 * To co-operate with that hack, we do hack again.
1889 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1891 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL)
1892 ret = qgroup_account_snapshot(trans, root, parent_root,
1893 pending->inherit, objectid);
1894 else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
1895 ret = btrfs_qgroup_inherit(trans, root->root_key.objectid, objectid,
1896 parent_root->root_key.objectid, pending->inherit);
1900 ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1901 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1903 /* We have check then name at the beginning, so it is impossible. */
1904 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1906 btrfs_abort_transaction(trans, ret);
1910 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1911 fname.disk_name.len * 2);
1912 inode_set_mtime_to_ts(parent_inode,
1913 inode_set_ctime_current(parent_inode));
1914 ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode));
1916 btrfs_abort_transaction(trans, ret);
1919 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1920 BTRFS_UUID_KEY_SUBVOL,
1923 btrfs_abort_transaction(trans, ret);
1926 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1927 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1928 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1930 if (ret && ret != -EEXIST) {
1931 btrfs_abort_transaction(trans, ret);
1937 pending->error = ret;
1939 trans->block_rsv = rsv;
1940 trans->bytes_reserved = 0;
1942 btrfs_clear_skip_qgroup(trans);
1944 fscrypt_free_filename(&fname);
1946 kfree(new_root_item);
1947 pending->root_item = NULL;
1948 btrfs_free_path(path);
1949 pending->path = NULL;
1955 * create all the snapshots we've scheduled for creation
1957 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1959 struct btrfs_pending_snapshot *pending, *next;
1960 struct list_head *head = &trans->transaction->pending_snapshots;
1963 list_for_each_entry_safe(pending, next, head, list) {
1964 list_del(&pending->list);
1965 ret = create_pending_snapshot(trans, pending);
1972 static void update_super_roots(struct btrfs_fs_info *fs_info)
1974 struct btrfs_root_item *root_item;
1975 struct btrfs_super_block *super;
1977 super = fs_info->super_copy;
1979 root_item = &fs_info->chunk_root->root_item;
1980 super->chunk_root = root_item->bytenr;
1981 super->chunk_root_generation = root_item->generation;
1982 super->chunk_root_level = root_item->level;
1984 root_item = &fs_info->tree_root->root_item;
1985 super->root = root_item->bytenr;
1986 super->generation = root_item->generation;
1987 super->root_level = root_item->level;
1988 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1989 super->cache_generation = root_item->generation;
1990 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1991 super->cache_generation = 0;
1992 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1993 super->uuid_tree_generation = root_item->generation;
1996 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1998 struct btrfs_transaction *trans;
2001 spin_lock(&info->trans_lock);
2002 trans = info->running_transaction;
2004 ret = (trans->state >= TRANS_STATE_COMMIT_START);
2005 spin_unlock(&info->trans_lock);
2009 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
2011 struct btrfs_transaction *trans;
2014 spin_lock(&info->trans_lock);
2015 trans = info->running_transaction;
2017 ret = is_transaction_blocked(trans);
2018 spin_unlock(&info->trans_lock);
2022 void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
2024 struct btrfs_fs_info *fs_info = trans->fs_info;
2025 struct btrfs_transaction *cur_trans;
2027 /* Kick the transaction kthread. */
2028 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2029 wake_up_process(fs_info->transaction_kthread);
2031 /* take transaction reference */
2032 cur_trans = trans->transaction;
2033 refcount_inc(&cur_trans->use_count);
2035 btrfs_end_transaction(trans);
2038 * Wait for the current transaction commit to start and block
2039 * subsequent transaction joins
2041 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2042 wait_event(fs_info->transaction_blocked_wait,
2043 cur_trans->state >= TRANS_STATE_COMMIT_START ||
2044 TRANS_ABORTED(cur_trans));
2045 btrfs_put_transaction(cur_trans);
2048 static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
2050 struct btrfs_fs_info *fs_info = trans->fs_info;
2051 struct btrfs_transaction *cur_trans = trans->transaction;
2053 WARN_ON(refcount_read(&trans->use_count) > 1);
2055 btrfs_abort_transaction(trans, err);
2057 spin_lock(&fs_info->trans_lock);
2060 * If the transaction is removed from the list, it means this
2061 * transaction has been committed successfully, so it is impossible
2062 * to call the cleanup function.
2064 BUG_ON(list_empty(&cur_trans->list));
2066 if (cur_trans == fs_info->running_transaction) {
2067 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2068 spin_unlock(&fs_info->trans_lock);
2071 * The thread has already released the lockdep map as reader
2072 * already in btrfs_commit_transaction().
2074 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2075 wait_event(cur_trans->writer_wait,
2076 atomic_read(&cur_trans->num_writers) == 1);
2078 spin_lock(&fs_info->trans_lock);
2082 * Now that we know no one else is still using the transaction we can
2083 * remove the transaction from the list of transactions. This avoids
2084 * the transaction kthread from cleaning up the transaction while some
2085 * other task is still using it, which could result in a use-after-free
2086 * on things like log trees, as it forces the transaction kthread to
2087 * wait for this transaction to be cleaned up by us.
2089 list_del_init(&cur_trans->list);
2091 spin_unlock(&fs_info->trans_lock);
2093 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
2095 spin_lock(&fs_info->trans_lock);
2096 if (cur_trans == fs_info->running_transaction)
2097 fs_info->running_transaction = NULL;
2098 spin_unlock(&fs_info->trans_lock);
2100 if (trans->type & __TRANS_FREEZABLE)
2101 sb_end_intwrite(fs_info->sb);
2102 btrfs_put_transaction(cur_trans);
2103 btrfs_put_transaction(cur_trans);
2105 trace_btrfs_transaction_commit(fs_info);
2107 if (current->journal_info == trans)
2108 current->journal_info = NULL;
2111 * If relocation is running, we can't cancel scrub because that will
2112 * result in a deadlock. Before relocating a block group, relocation
2113 * pauses scrub, then starts and commits a transaction before unpausing
2114 * scrub. If the transaction commit is being done by the relocation
2115 * task or triggered by another task and the relocation task is waiting
2116 * for the commit, and we end up here due to an error in the commit
2117 * path, then calling btrfs_scrub_cancel() will deadlock, as we are
2118 * asking for scrub to stop while having it asked to be paused higher
2119 * above in relocation code.
2121 if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
2122 btrfs_scrub_cancel(fs_info);
2124 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2128 * Release reserved delayed ref space of all pending block groups of the
2129 * transaction and remove them from the list
2131 static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2133 struct btrfs_fs_info *fs_info = trans->fs_info;
2134 struct btrfs_block_group *block_group, *tmp;
2136 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2137 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2138 list_del_init(&block_group->bg_list);
2142 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2145 * We use try_to_writeback_inodes_sb() here because if we used
2146 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2147 * Currently are holding the fs freeze lock, if we do an async flush
2148 * we'll do btrfs_join_transaction() and deadlock because we need to
2149 * wait for the fs freeze lock. Using the direct flushing we benefit
2150 * from already being in a transaction and our join_transaction doesn't
2151 * have to re-take the fs freeze lock.
2153 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2154 * if it can read lock sb->s_umount. It will always be able to lock it,
2155 * except when the filesystem is being unmounted or being frozen, but in
2156 * those cases sync_filesystem() is called, which results in calling
2157 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2158 * Note that we don't call writeback_inodes_sb() directly, because it
2159 * will emit a warning if sb->s_umount is not locked.
2161 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2162 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2166 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2168 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2169 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2173 * Add a pending snapshot associated with the given transaction handle to the
2174 * respective handle. This must be called after the transaction commit started
2175 * and while holding fs_info->trans_lock.
2176 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2177 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2180 static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2182 struct btrfs_transaction *cur_trans = trans->transaction;
2184 if (!trans->pending_snapshot)
2187 lockdep_assert_held(&trans->fs_info->trans_lock);
2188 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP);
2190 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2193 static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
2195 fs_info->commit_stats.commit_count++;
2196 fs_info->commit_stats.last_commit_dur = interval;
2197 fs_info->commit_stats.max_commit_dur =
2198 max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2199 fs_info->commit_stats.total_commit_dur += interval;
2202 int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2204 struct btrfs_fs_info *fs_info = trans->fs_info;
2205 struct btrfs_transaction *cur_trans = trans->transaction;
2206 struct btrfs_transaction *prev_trans = NULL;
2211 ASSERT(refcount_read(&trans->use_count) == 1);
2212 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2214 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2216 /* Stop the commit early if ->aborted is set */
2217 if (TRANS_ABORTED(cur_trans)) {
2218 ret = cur_trans->aborted;
2219 goto lockdep_trans_commit_start_release;
2222 btrfs_trans_release_metadata(trans);
2223 trans->block_rsv = NULL;
2226 * We only want one transaction commit doing the flushing so we do not
2227 * waste a bunch of time on lock contention on the extent root node.
2229 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2230 &cur_trans->delayed_refs.flags)) {
2232 * Make a pass through all the delayed refs we have so far.
2233 * Any running threads may add more while we are here.
2235 ret = btrfs_run_delayed_refs(trans, 0);
2237 goto lockdep_trans_commit_start_release;
2240 btrfs_create_pending_block_groups(trans);
2242 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2245 /* this mutex is also taken before trying to set
2246 * block groups readonly. We need to make sure
2247 * that nobody has set a block group readonly
2248 * after a extents from that block group have been
2249 * allocated for cache files. btrfs_set_block_group_ro
2250 * will wait for the transaction to commit if it
2251 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2253 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2254 * only one process starts all the block group IO. It wouldn't
2255 * hurt to have more than one go through, but there's no
2256 * real advantage to it either.
2258 mutex_lock(&fs_info->ro_block_group_mutex);
2259 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2262 mutex_unlock(&fs_info->ro_block_group_mutex);
2265 ret = btrfs_start_dirty_block_groups(trans);
2267 goto lockdep_trans_commit_start_release;
2271 spin_lock(&fs_info->trans_lock);
2272 if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) {
2273 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2275 add_pending_snapshot(trans);
2277 spin_unlock(&fs_info->trans_lock);
2278 refcount_inc(&cur_trans->use_count);
2280 if (trans->in_fsync)
2281 want_state = TRANS_STATE_SUPER_COMMITTED;
2283 btrfs_trans_state_lockdep_release(fs_info,
2284 BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2285 ret = btrfs_end_transaction(trans);
2286 wait_for_commit(cur_trans, want_state);
2288 if (TRANS_ABORTED(cur_trans))
2289 ret = cur_trans->aborted;
2291 btrfs_put_transaction(cur_trans);
2296 cur_trans->state = TRANS_STATE_COMMIT_PREP;
2297 wake_up(&fs_info->transaction_blocked_wait);
2298 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2300 if (cur_trans->list.prev != &fs_info->trans_list) {
2301 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2303 if (trans->in_fsync)
2304 want_state = TRANS_STATE_SUPER_COMMITTED;
2306 prev_trans = list_entry(cur_trans->list.prev,
2307 struct btrfs_transaction, list);
2308 if (prev_trans->state < want_state) {
2309 refcount_inc(&prev_trans->use_count);
2310 spin_unlock(&fs_info->trans_lock);
2312 wait_for_commit(prev_trans, want_state);
2314 ret = READ_ONCE(prev_trans->aborted);
2316 btrfs_put_transaction(prev_trans);
2318 goto lockdep_release;
2319 spin_lock(&fs_info->trans_lock);
2323 * The previous transaction was aborted and was already removed
2324 * from the list of transactions at fs_info->trans_list. So we
2325 * abort to prevent writing a new superblock that reflects a
2326 * corrupt state (pointing to trees with unwritten nodes/leafs).
2328 if (BTRFS_FS_ERROR(fs_info)) {
2329 spin_unlock(&fs_info->trans_lock);
2331 goto lockdep_release;
2335 cur_trans->state = TRANS_STATE_COMMIT_START;
2336 wake_up(&fs_info->transaction_blocked_wait);
2337 spin_unlock(&fs_info->trans_lock);
2340 * Get the time spent on the work done by the commit thread and not
2341 * the time spent waiting on a previous commit
2343 start_time = ktime_get_ns();
2345 extwriter_counter_dec(cur_trans, trans->type);
2347 ret = btrfs_start_delalloc_flush(fs_info);
2349 goto lockdep_release;
2351 ret = btrfs_run_delayed_items(trans);
2353 goto lockdep_release;
2356 * The thread has started/joined the transaction thus it holds the
2357 * lockdep map as a reader. It has to release it before acquiring the
2358 * lockdep map as a writer.
2360 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2361 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2362 wait_event(cur_trans->writer_wait,
2363 extwriter_counter_read(cur_trans) == 0);
2365 /* some pending stuffs might be added after the previous flush. */
2366 ret = btrfs_run_delayed_items(trans);
2368 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2369 goto cleanup_transaction;
2372 btrfs_wait_delalloc_flush(fs_info);
2375 * Wait for all ordered extents started by a fast fsync that joined this
2376 * transaction. Otherwise if this transaction commits before the ordered
2377 * extents complete we lose logged data after a power failure.
2379 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2380 wait_event(cur_trans->pending_wait,
2381 atomic_read(&cur_trans->pending_ordered) == 0);
2383 btrfs_scrub_pause(fs_info);
2385 * Ok now we need to make sure to block out any other joins while we
2386 * commit the transaction. We could have started a join before setting
2387 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2389 spin_lock(&fs_info->trans_lock);
2390 add_pending_snapshot(trans);
2391 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2392 spin_unlock(&fs_info->trans_lock);
2395 * The thread has started/joined the transaction thus it holds the
2396 * lockdep map as a reader. It has to release it before acquiring the
2397 * lockdep map as a writer.
2399 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2400 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2401 wait_event(cur_trans->writer_wait,
2402 atomic_read(&cur_trans->num_writers) == 1);
2405 * Make lockdep happy by acquiring the state locks after
2406 * btrfs_trans_num_writers is released. If we acquired the state locks
2407 * before releasing the btrfs_trans_num_writers lock then lockdep would
2408 * complain because we did not follow the reverse order unlocking rule.
2410 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2411 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2412 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2415 * We've started the commit, clear the flag in case we were triggered to
2416 * do an async commit but somebody else started before the transaction
2417 * kthread could do the work.
2419 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2421 if (TRANS_ABORTED(cur_trans)) {
2422 ret = cur_trans->aborted;
2423 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2424 goto scrub_continue;
2427 * the reloc mutex makes sure that we stop
2428 * the balancing code from coming in and moving
2429 * extents around in the middle of the commit
2431 mutex_lock(&fs_info->reloc_mutex);
2434 * We needn't worry about the delayed items because we will
2435 * deal with them in create_pending_snapshot(), which is the
2436 * core function of the snapshot creation.
2438 ret = create_pending_snapshots(trans);
2443 * We insert the dir indexes of the snapshots and update the inode
2444 * of the snapshots' parents after the snapshot creation, so there
2445 * are some delayed items which are not dealt with. Now deal with
2448 * We needn't worry that this operation will corrupt the snapshots,
2449 * because all the tree which are snapshoted will be forced to COW
2450 * the nodes and leaves.
2452 ret = btrfs_run_delayed_items(trans);
2456 ret = btrfs_run_delayed_refs(trans, U64_MAX);
2461 * make sure none of the code above managed to slip in a
2464 btrfs_assert_delayed_root_empty(fs_info);
2466 WARN_ON(cur_trans != trans->transaction);
2468 ret = commit_fs_roots(trans);
2472 /* commit_fs_roots gets rid of all the tree log roots, it is now
2473 * safe to free the root of tree log roots
2475 btrfs_free_log_root_tree(trans, fs_info);
2478 * Since fs roots are all committed, we can get a quite accurate
2479 * new_roots. So let's do quota accounting.
2481 ret = btrfs_qgroup_account_extents(trans);
2485 ret = commit_cowonly_roots(trans);
2490 * The tasks which save the space cache and inode cache may also
2491 * update ->aborted, check it.
2493 if (TRANS_ABORTED(cur_trans)) {
2494 ret = cur_trans->aborted;
2498 cur_trans = fs_info->running_transaction;
2500 btrfs_set_root_node(&fs_info->tree_root->root_item,
2501 fs_info->tree_root->node);
2502 list_add_tail(&fs_info->tree_root->dirty_list,
2503 &cur_trans->switch_commits);
2505 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2506 fs_info->chunk_root->node);
2507 list_add_tail(&fs_info->chunk_root->dirty_list,
2508 &cur_trans->switch_commits);
2510 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2511 btrfs_set_root_node(&fs_info->block_group_root->root_item,
2512 fs_info->block_group_root->node);
2513 list_add_tail(&fs_info->block_group_root->dirty_list,
2514 &cur_trans->switch_commits);
2517 switch_commit_roots(trans);
2519 ASSERT(list_empty(&cur_trans->dirty_bgs));
2520 ASSERT(list_empty(&cur_trans->io_bgs));
2521 update_super_roots(fs_info);
2523 btrfs_set_super_log_root(fs_info->super_copy, 0);
2524 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2525 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2526 sizeof(*fs_info->super_copy));
2528 btrfs_commit_device_sizes(cur_trans);
2530 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2531 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2533 btrfs_trans_release_chunk_metadata(trans);
2536 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2537 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2538 * make sure that before we commit our superblock, no other task can
2539 * start a new transaction and commit a log tree before we commit our
2540 * superblock. Anyone trying to commit a log tree locks this mutex before
2541 * writing its superblock.
2543 mutex_lock(&fs_info->tree_log_mutex);
2545 spin_lock(&fs_info->trans_lock);
2546 cur_trans->state = TRANS_STATE_UNBLOCKED;
2547 fs_info->running_transaction = NULL;
2548 spin_unlock(&fs_info->trans_lock);
2549 mutex_unlock(&fs_info->reloc_mutex);
2551 wake_up(&fs_info->transaction_wait);
2552 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2554 /* If we have features changed, wake up the cleaner to update sysfs. */
2555 if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
2556 fs_info->cleaner_kthread)
2557 wake_up_process(fs_info->cleaner_kthread);
2559 ret = btrfs_write_and_wait_transaction(trans);
2561 btrfs_handle_fs_error(fs_info, ret,
2562 "Error while writing out transaction");
2563 mutex_unlock(&fs_info->tree_log_mutex);
2564 goto scrub_continue;
2567 ret = write_all_supers(fs_info, 0);
2569 * the super is written, we can safely allow the tree-loggers
2570 * to go about their business
2572 mutex_unlock(&fs_info->tree_log_mutex);
2574 goto scrub_continue;
2577 * We needn't acquire the lock here because there is no other task
2578 * which can change it.
2580 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2581 wake_up(&cur_trans->commit_wait);
2582 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2584 btrfs_finish_extent_commit(trans);
2586 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2587 btrfs_clear_space_info_full(fs_info);
2589 btrfs_set_last_trans_committed(fs_info, cur_trans->transid);
2591 * We needn't acquire the lock here because there is no other task
2592 * which can change it.
2594 cur_trans->state = TRANS_STATE_COMPLETED;
2595 wake_up(&cur_trans->commit_wait);
2596 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2598 spin_lock(&fs_info->trans_lock);
2599 list_del_init(&cur_trans->list);
2600 spin_unlock(&fs_info->trans_lock);
2602 btrfs_put_transaction(cur_trans);
2603 btrfs_put_transaction(cur_trans);
2605 if (trans->type & __TRANS_FREEZABLE)
2606 sb_end_intwrite(fs_info->sb);
2608 trace_btrfs_transaction_commit(fs_info);
2610 interval = ktime_get_ns() - start_time;
2612 btrfs_scrub_continue(fs_info);
2614 if (current->journal_info == trans)
2615 current->journal_info = NULL;
2617 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2619 update_commit_stats(fs_info, interval);
2624 mutex_unlock(&fs_info->reloc_mutex);
2625 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2627 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2628 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2629 btrfs_scrub_continue(fs_info);
2630 cleanup_transaction:
2631 btrfs_trans_release_metadata(trans);
2632 btrfs_cleanup_pending_block_groups(trans);
2633 btrfs_trans_release_chunk_metadata(trans);
2634 trans->block_rsv = NULL;
2635 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2636 if (current->journal_info == trans)
2637 current->journal_info = NULL;
2638 cleanup_transaction(trans, ret);
2643 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2644 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2645 goto cleanup_transaction;
2647 lockdep_trans_commit_start_release:
2648 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2649 btrfs_end_transaction(trans);
2654 * return < 0 if error
2655 * 0 if there are no more dead_roots at the time of call
2656 * 1 there are more to be processed, call me again
2658 * The return value indicates there are certainly more snapshots to delete, but
2659 * if there comes a new one during processing, it may return 0. We don't mind,
2660 * because btrfs_commit_super will poke cleaner thread and it will process it a
2661 * few seconds later.
2663 int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2665 struct btrfs_root *root;
2668 spin_lock(&fs_info->trans_lock);
2669 if (list_empty(&fs_info->dead_roots)) {
2670 spin_unlock(&fs_info->trans_lock);
2673 root = list_first_entry(&fs_info->dead_roots,
2674 struct btrfs_root, root_list);
2675 list_del_init(&root->root_list);
2676 spin_unlock(&fs_info->trans_lock);
2678 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2680 btrfs_kill_all_delayed_nodes(root);
2682 if (btrfs_header_backref_rev(root->node) <
2683 BTRFS_MIXED_BACKREF_REV)
2684 ret = btrfs_drop_snapshot(root, 0, 0);
2686 ret = btrfs_drop_snapshot(root, 1, 0);
2688 btrfs_put_root(root);
2689 return (ret < 0) ? 0 : 1;
2693 * We only mark the transaction aborted and then set the file system read-only.
2694 * This will prevent new transactions from starting or trying to join this
2697 * This means that error recovery at the call site is limited to freeing
2698 * any local memory allocations and passing the error code up without
2699 * further cleanup. The transaction should complete as it normally would
2700 * in the call path but will return -EIO.
2702 * We'll complete the cleanup in btrfs_end_transaction and
2703 * btrfs_commit_transaction.
2705 void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
2706 const char *function,
2707 unsigned int line, int error, bool first_hit)
2709 struct btrfs_fs_info *fs_info = trans->fs_info;
2711 WRITE_ONCE(trans->aborted, error);
2712 WRITE_ONCE(trans->transaction->aborted, error);
2713 if (first_hit && error == -ENOSPC)
2714 btrfs_dump_space_info_for_trans_abort(fs_info);
2715 /* Wake up anybody who may be waiting on this transaction */
2716 wake_up(&fs_info->transaction_wait);
2717 wake_up(&fs_info->transaction_blocked_wait);
2718 __btrfs_handle_fs_error(fs_info, function, line, error, NULL);
2721 int __init btrfs_transaction_init(void)
2723 btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
2724 sizeof(struct btrfs_trans_handle), 0,
2725 SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
2726 if (!btrfs_trans_handle_cachep)
2731 void __cold btrfs_transaction_exit(void)
2733 kmem_cache_destroy(btrfs_trans_handle_cachep);