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/writeback.h>
10 #include <linux/pagemap.h>
11 #include <linux/blkdev.h>
12 #include <linux/uuid.h>
16 #include "transaction.h"
20 #include "dev-replace.h"
22 #include "block-group.h"
23 #include "space-info.h"
26 #define BTRFS_ROOT_TRANS_TAG 0
29 * Transaction states and transitions
31 * No running transaction (fs tree blocks are not modified)
34 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
36 * Transaction N [[TRANS_STATE_RUNNING]]
38 * | New trans handles can be attached to transaction N by calling all
39 * | start_transaction() variants.
42 * | Call btrfs_commit_transaction() on any trans handle attached to
45 * Transaction N [[TRANS_STATE_COMMIT_START]]
47 * | Will wait for previous running transaction to completely finish if there
50 * | Then one of the following happes:
51 * | - Wait for all other trans handle holders to release.
52 * | The btrfs_commit_transaction() caller will do the commit work.
53 * | - Wait for current transaction to be committed by others.
54 * | Other btrfs_commit_transaction() caller will do the commit work.
56 * | At this stage, only btrfs_join_transaction*() variants can attach
57 * | to this running transaction.
58 * | All other variants will wait for current one to finish and attach to
62 * | Caller is chosen to commit transaction N, and all other trans handle
63 * | haven been released.
65 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
67 * | The heavy lifting transaction work is started.
68 * | From running delayed refs (modifying extent tree) to creating pending
69 * | snapshots, running qgroups.
70 * | In short, modify supporting trees to reflect modifications of subvolume
73 * | At this stage, all start_transaction() calls will wait for this
74 * | transaction to finish and attach to transaction N+1.
77 * | Until all supporting trees are updated.
79 * Transaction N [[TRANS_STATE_UNBLOCKED]]
81 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
82 * | need to write them back to disk and update |
85 * | At this stage, new transaction is allowed to |
87 * | All new start_transaction() calls will be |
88 * | attached to transid N+1. |
91 * | Until all tree blocks are super blocks are |
92 * | written to block devices |
94 * Transaction N [[TRANS_STATE_COMPLETED]] V
95 * All tree blocks and super blocks are written. Transaction N+1
96 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
97 * data structures will be cleaned up. | Life goes on
99 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
100 [TRANS_STATE_RUNNING] = 0U,
101 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
102 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
105 __TRANS_JOIN_NOSTART),
106 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
109 __TRANS_JOIN_NOLOCK |
110 __TRANS_JOIN_NOSTART),
111 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
114 __TRANS_JOIN_NOLOCK |
115 __TRANS_JOIN_NOSTART),
116 [TRANS_STATE_COMPLETED] = (__TRANS_START |
119 __TRANS_JOIN_NOLOCK |
120 __TRANS_JOIN_NOSTART),
123 void btrfs_put_transaction(struct btrfs_transaction *transaction)
125 WARN_ON(refcount_read(&transaction->use_count) == 0);
126 if (refcount_dec_and_test(&transaction->use_count)) {
127 BUG_ON(!list_empty(&transaction->list));
128 WARN_ON(!RB_EMPTY_ROOT(
129 &transaction->delayed_refs.href_root.rb_root));
130 WARN_ON(!RB_EMPTY_ROOT(
131 &transaction->delayed_refs.dirty_extent_root));
132 if (transaction->delayed_refs.pending_csums)
133 btrfs_err(transaction->fs_info,
134 "pending csums is %llu",
135 transaction->delayed_refs.pending_csums);
137 * If any block groups are found in ->deleted_bgs then it's
138 * because the transaction was aborted and a commit did not
139 * happen (things failed before writing the new superblock
140 * and calling btrfs_finish_extent_commit()), so we can not
141 * discard the physical locations of the block groups.
143 while (!list_empty(&transaction->deleted_bgs)) {
144 struct btrfs_block_group *cache;
146 cache = list_first_entry(&transaction->deleted_bgs,
147 struct btrfs_block_group,
149 list_del_init(&cache->bg_list);
150 btrfs_unfreeze_block_group(cache);
151 btrfs_put_block_group(cache);
153 WARN_ON(!list_empty(&transaction->dev_update_list));
158 static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
160 struct btrfs_transaction *cur_trans = trans->transaction;
161 struct btrfs_fs_info *fs_info = trans->fs_info;
162 struct btrfs_root *root, *tmp;
163 struct btrfs_caching_control *caching_ctl, *next;
166 * At this point no one can be using this transaction to modify any tree
167 * and no one can start another transaction to modify any tree either.
169 ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
171 down_write(&fs_info->commit_root_sem);
173 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
174 fs_info->last_reloc_trans = trans->transid;
176 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
178 list_del_init(&root->dirty_list);
179 free_extent_buffer(root->commit_root);
180 root->commit_root = btrfs_root_node(root);
181 extent_io_tree_release(&root->dirty_log_pages);
182 btrfs_qgroup_clean_swapped_blocks(root);
185 /* We can free old roots now. */
186 spin_lock(&cur_trans->dropped_roots_lock);
187 while (!list_empty(&cur_trans->dropped_roots)) {
188 root = list_first_entry(&cur_trans->dropped_roots,
189 struct btrfs_root, root_list);
190 list_del_init(&root->root_list);
191 spin_unlock(&cur_trans->dropped_roots_lock);
192 btrfs_free_log(trans, root);
193 btrfs_drop_and_free_fs_root(fs_info, root);
194 spin_lock(&cur_trans->dropped_roots_lock);
196 spin_unlock(&cur_trans->dropped_roots_lock);
199 * We have to update the last_byte_to_unpin under the commit_root_sem,
200 * at the same time we swap out the commit roots.
202 * This is because we must have a real view of the last spot the caching
203 * kthreads were while caching. Consider the following views of the
204 * extent tree for a block group
207 * +----+----+----+----+----+----+----+
208 * |\\\\| |\\\\|\\\\| |\\\\|\\\\|
209 * +----+----+----+----+----+----+----+
213 * +----+----+----+----+----+----+----+
214 * | | | |\\\\| | |\\\\|
215 * +----+----+----+----+----+----+----+
218 * If the cache_ctl->progress was at 3, then we are only allowed to
219 * unpin [0,1) and [2,3], because the caching thread has already
220 * processed those extents. We are not allowed to unpin [5,6), because
221 * the caching thread will re-start it's search from 3, and thus find
222 * the hole from [4,6) to add to the free space cache.
224 write_lock(&fs_info->block_group_cache_lock);
225 list_for_each_entry_safe(caching_ctl, next,
226 &fs_info->caching_block_groups, list) {
227 struct btrfs_block_group *cache = caching_ctl->block_group;
229 if (btrfs_block_group_done(cache)) {
230 cache->last_byte_to_unpin = (u64)-1;
231 list_del_init(&caching_ctl->list);
232 btrfs_put_caching_control(caching_ctl);
234 cache->last_byte_to_unpin = caching_ctl->progress;
237 write_unlock(&fs_info->block_group_cache_lock);
238 up_write(&fs_info->commit_root_sem);
241 static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
244 if (type & TRANS_EXTWRITERS)
245 atomic_inc(&trans->num_extwriters);
248 static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
251 if (type & TRANS_EXTWRITERS)
252 atomic_dec(&trans->num_extwriters);
255 static inline void extwriter_counter_init(struct btrfs_transaction *trans,
258 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
261 static inline int extwriter_counter_read(struct btrfs_transaction *trans)
263 return atomic_read(&trans->num_extwriters);
267 * To be called after doing the chunk btree updates right after allocating a new
268 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
269 * chunk after all chunk btree updates and after finishing the second phase of
270 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
271 * group had its chunk item insertion delayed to the second phase.
273 void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
275 struct btrfs_fs_info *fs_info = trans->fs_info;
277 if (!trans->chunk_bytes_reserved)
280 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
281 trans->chunk_bytes_reserved, NULL);
282 trans->chunk_bytes_reserved = 0;
286 * either allocate a new transaction or hop into the existing one
288 static noinline int join_transaction(struct btrfs_fs_info *fs_info,
291 struct btrfs_transaction *cur_trans;
293 spin_lock(&fs_info->trans_lock);
295 /* The file system has been taken offline. No new transactions. */
296 if (BTRFS_FS_ERROR(fs_info)) {
297 spin_unlock(&fs_info->trans_lock);
301 cur_trans = fs_info->running_transaction;
303 if (TRANS_ABORTED(cur_trans)) {
304 spin_unlock(&fs_info->trans_lock);
305 return cur_trans->aborted;
307 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
308 spin_unlock(&fs_info->trans_lock);
311 refcount_inc(&cur_trans->use_count);
312 atomic_inc(&cur_trans->num_writers);
313 extwriter_counter_inc(cur_trans, type);
314 spin_unlock(&fs_info->trans_lock);
317 spin_unlock(&fs_info->trans_lock);
320 * If we are ATTACH, we just want to catch the current transaction,
321 * and commit it. If there is no transaction, just return ENOENT.
323 if (type == TRANS_ATTACH)
327 * JOIN_NOLOCK only happens during the transaction commit, so
328 * it is impossible that ->running_transaction is NULL
330 BUG_ON(type == TRANS_JOIN_NOLOCK);
332 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
336 spin_lock(&fs_info->trans_lock);
337 if (fs_info->running_transaction) {
339 * someone started a transaction after we unlocked. Make sure
340 * to redo the checks above
344 } else if (BTRFS_FS_ERROR(fs_info)) {
345 spin_unlock(&fs_info->trans_lock);
350 cur_trans->fs_info = fs_info;
351 atomic_set(&cur_trans->pending_ordered, 0);
352 init_waitqueue_head(&cur_trans->pending_wait);
353 atomic_set(&cur_trans->num_writers, 1);
354 extwriter_counter_init(cur_trans, type);
355 init_waitqueue_head(&cur_trans->writer_wait);
356 init_waitqueue_head(&cur_trans->commit_wait);
357 cur_trans->state = TRANS_STATE_RUNNING;
359 * One for this trans handle, one so it will live on until we
360 * commit the transaction.
362 refcount_set(&cur_trans->use_count, 2);
363 cur_trans->flags = 0;
364 cur_trans->start_time = ktime_get_seconds();
366 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
368 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
369 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
370 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
373 * although the tree mod log is per file system and not per transaction,
374 * the log must never go across transaction boundaries.
377 if (!list_empty(&fs_info->tree_mod_seq_list))
378 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
379 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
380 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
381 atomic64_set(&fs_info->tree_mod_seq, 0);
383 spin_lock_init(&cur_trans->delayed_refs.lock);
385 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
386 INIT_LIST_HEAD(&cur_trans->dev_update_list);
387 INIT_LIST_HEAD(&cur_trans->switch_commits);
388 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
389 INIT_LIST_HEAD(&cur_trans->io_bgs);
390 INIT_LIST_HEAD(&cur_trans->dropped_roots);
391 mutex_init(&cur_trans->cache_write_mutex);
392 spin_lock_init(&cur_trans->dirty_bgs_lock);
393 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
394 spin_lock_init(&cur_trans->dropped_roots_lock);
395 INIT_LIST_HEAD(&cur_trans->releasing_ebs);
396 spin_lock_init(&cur_trans->releasing_ebs_lock);
397 list_add_tail(&cur_trans->list, &fs_info->trans_list);
398 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
399 IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
400 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
401 IO_TREE_FS_PINNED_EXTENTS, NULL);
402 fs_info->generation++;
403 cur_trans->transid = fs_info->generation;
404 fs_info->running_transaction = cur_trans;
405 cur_trans->aborted = 0;
406 spin_unlock(&fs_info->trans_lock);
412 * This does all the record keeping required to make sure that a shareable root
413 * is properly recorded in a given transaction. This is required to make sure
414 * the old root from before we joined the transaction is deleted when the
415 * transaction commits.
417 static int record_root_in_trans(struct btrfs_trans_handle *trans,
418 struct btrfs_root *root,
421 struct btrfs_fs_info *fs_info = root->fs_info;
424 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
425 root->last_trans < trans->transid) || force) {
426 WARN_ON(!force && root->commit_root != root->node);
429 * see below for IN_TRANS_SETUP usage rules
430 * we have the reloc mutex held now, so there
431 * is only one writer in this function
433 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
435 /* make sure readers find IN_TRANS_SETUP before
436 * they find our root->last_trans update
440 spin_lock(&fs_info->fs_roots_radix_lock);
441 if (root->last_trans == trans->transid && !force) {
442 spin_unlock(&fs_info->fs_roots_radix_lock);
445 radix_tree_tag_set(&fs_info->fs_roots_radix,
446 (unsigned long)root->root_key.objectid,
447 BTRFS_ROOT_TRANS_TAG);
448 spin_unlock(&fs_info->fs_roots_radix_lock);
449 root->last_trans = trans->transid;
451 /* this is pretty tricky. We don't want to
452 * take the relocation lock in btrfs_record_root_in_trans
453 * unless we're really doing the first setup for this root in
456 * Normally we'd use root->last_trans as a flag to decide
457 * if we want to take the expensive mutex.
459 * But, we have to set root->last_trans before we
460 * init the relocation root, otherwise, we trip over warnings
461 * in ctree.c. The solution used here is to flag ourselves
462 * with root IN_TRANS_SETUP. When this is 1, we're still
463 * fixing up the reloc trees and everyone must wait.
465 * When this is zero, they can trust root->last_trans and fly
466 * through btrfs_record_root_in_trans without having to take the
467 * lock. smp_wmb() makes sure that all the writes above are
468 * done before we pop in the zero below
470 ret = btrfs_init_reloc_root(trans, root);
471 smp_mb__before_atomic();
472 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
478 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
479 struct btrfs_root *root)
481 struct btrfs_fs_info *fs_info = root->fs_info;
482 struct btrfs_transaction *cur_trans = trans->transaction;
484 /* Add ourselves to the transaction dropped list */
485 spin_lock(&cur_trans->dropped_roots_lock);
486 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
487 spin_unlock(&cur_trans->dropped_roots_lock);
489 /* Make sure we don't try to update the root at commit time */
490 spin_lock(&fs_info->fs_roots_radix_lock);
491 radix_tree_tag_clear(&fs_info->fs_roots_radix,
492 (unsigned long)root->root_key.objectid,
493 BTRFS_ROOT_TRANS_TAG);
494 spin_unlock(&fs_info->fs_roots_radix_lock);
497 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
498 struct btrfs_root *root)
500 struct btrfs_fs_info *fs_info = root->fs_info;
503 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
507 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
511 if (root->last_trans == trans->transid &&
512 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
515 mutex_lock(&fs_info->reloc_mutex);
516 ret = record_root_in_trans(trans, root, 0);
517 mutex_unlock(&fs_info->reloc_mutex);
522 static inline int is_transaction_blocked(struct btrfs_transaction *trans)
524 return (trans->state >= TRANS_STATE_COMMIT_START &&
525 trans->state < TRANS_STATE_UNBLOCKED &&
526 !TRANS_ABORTED(trans));
529 /* wait for commit against the current transaction to become unblocked
530 * when this is done, it is safe to start a new transaction, but the current
531 * transaction might not be fully on disk.
533 static void wait_current_trans(struct btrfs_fs_info *fs_info)
535 struct btrfs_transaction *cur_trans;
537 spin_lock(&fs_info->trans_lock);
538 cur_trans = fs_info->running_transaction;
539 if (cur_trans && is_transaction_blocked(cur_trans)) {
540 refcount_inc(&cur_trans->use_count);
541 spin_unlock(&fs_info->trans_lock);
543 wait_event(fs_info->transaction_wait,
544 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
545 TRANS_ABORTED(cur_trans));
546 btrfs_put_transaction(cur_trans);
548 spin_unlock(&fs_info->trans_lock);
552 static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
554 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
557 if (type == TRANS_START)
563 static inline bool need_reserve_reloc_root(struct btrfs_root *root)
565 struct btrfs_fs_info *fs_info = root->fs_info;
567 if (!fs_info->reloc_ctl ||
568 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
569 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
576 static struct btrfs_trans_handle *
577 start_transaction(struct btrfs_root *root, unsigned int num_items,
578 unsigned int type, enum btrfs_reserve_flush_enum flush,
579 bool enforce_qgroups)
581 struct btrfs_fs_info *fs_info = root->fs_info;
582 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
583 struct btrfs_trans_handle *h;
584 struct btrfs_transaction *cur_trans;
586 u64 qgroup_reserved = 0;
587 bool reloc_reserved = false;
588 bool do_chunk_alloc = false;
591 if (BTRFS_FS_ERROR(fs_info))
592 return ERR_PTR(-EROFS);
594 if (current->journal_info) {
595 WARN_ON(type & TRANS_EXTWRITERS);
596 h = current->journal_info;
597 refcount_inc(&h->use_count);
598 WARN_ON(refcount_read(&h->use_count) > 2);
599 h->orig_rsv = h->block_rsv;
605 * Do the reservation before we join the transaction so we can do all
606 * the appropriate flushing if need be.
608 if (num_items && root != fs_info->chunk_root) {
609 struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
610 u64 delayed_refs_bytes = 0;
612 qgroup_reserved = num_items * fs_info->nodesize;
613 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
619 * We want to reserve all the bytes we may need all at once, so
620 * we only do 1 enospc flushing cycle per transaction start. We
621 * accomplish this by simply assuming we'll do 2 x num_items
622 * worth of delayed refs updates in this trans handle, and
623 * refill that amount for whatever is missing in the reserve.
625 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
626 if (flush == BTRFS_RESERVE_FLUSH_ALL &&
627 delayed_refs_rsv->full == 0) {
628 delayed_refs_bytes = num_bytes;
633 * Do the reservation for the relocation root creation
635 if (need_reserve_reloc_root(root)) {
636 num_bytes += fs_info->nodesize;
637 reloc_reserved = true;
640 ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes, flush);
643 if (delayed_refs_bytes) {
644 btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
646 num_bytes -= delayed_refs_bytes;
649 if (rsv->space_info->force_alloc)
650 do_chunk_alloc = true;
651 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
652 !delayed_refs_rsv->full) {
654 * Some people call with btrfs_start_transaction(root, 0)
655 * because they can be throttled, but have some other mechanism
656 * for reserving space. We still want these guys to refill the
657 * delayed block_rsv so just add 1 items worth of reservation
660 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
665 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
672 * If we are JOIN_NOLOCK we're already committing a transaction and
673 * waiting on this guy, so we don't need to do the sb_start_intwrite
674 * because we're already holding a ref. We need this because we could
675 * have raced in and did an fsync() on a file which can kick a commit
676 * and then we deadlock with somebody doing a freeze.
678 * If we are ATTACH, it means we just want to catch the current
679 * transaction and commit it, so we needn't do sb_start_intwrite().
681 if (type & __TRANS_FREEZABLE)
682 sb_start_intwrite(fs_info->sb);
684 if (may_wait_transaction(fs_info, type))
685 wait_current_trans(fs_info);
688 ret = join_transaction(fs_info, type);
690 wait_current_trans(fs_info);
691 if (unlikely(type == TRANS_ATTACH ||
692 type == TRANS_JOIN_NOSTART))
695 } while (ret == -EBUSY);
700 cur_trans = fs_info->running_transaction;
702 h->transid = cur_trans->transid;
703 h->transaction = cur_trans;
704 refcount_set(&h->use_count, 1);
705 h->fs_info = root->fs_info;
708 INIT_LIST_HEAD(&h->new_bgs);
711 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
712 may_wait_transaction(fs_info, type)) {
713 current->journal_info = h;
714 btrfs_commit_transaction(h);
719 trace_btrfs_space_reservation(fs_info, "transaction",
720 h->transid, num_bytes, 1);
721 h->block_rsv = &fs_info->trans_block_rsv;
722 h->bytes_reserved = num_bytes;
723 h->reloc_reserved = reloc_reserved;
727 if (!current->journal_info)
728 current->journal_info = h;
731 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
732 * ALLOC_FORCE the first run through, and then we won't allocate for
733 * anybody else who races in later. We don't care about the return
736 if (do_chunk_alloc && num_bytes) {
737 u64 flags = h->block_rsv->space_info->flags;
739 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
740 CHUNK_ALLOC_NO_FORCE);
744 * btrfs_record_root_in_trans() needs to alloc new extents, and may
745 * call btrfs_join_transaction() while we're also starting a
748 * Thus it need to be called after current->journal_info initialized,
749 * or we can deadlock.
751 ret = btrfs_record_root_in_trans(h, root);
754 * The transaction handle is fully initialized and linked with
755 * other structures so it needs to be ended in case of errors,
758 btrfs_end_transaction(h);
765 if (type & __TRANS_FREEZABLE)
766 sb_end_intwrite(fs_info->sb);
767 kmem_cache_free(btrfs_trans_handle_cachep, h);
770 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
773 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
777 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
778 unsigned int num_items)
780 return start_transaction(root, num_items, TRANS_START,
781 BTRFS_RESERVE_FLUSH_ALL, true);
784 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
785 struct btrfs_root *root,
786 unsigned int num_items)
788 return start_transaction(root, num_items, TRANS_START,
789 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
792 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
794 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
798 struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
800 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
801 BTRFS_RESERVE_NO_FLUSH, true);
805 * Similar to regular join but it never starts a transaction when none is
806 * running or after waiting for the current one to finish.
808 struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
810 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
811 BTRFS_RESERVE_NO_FLUSH, true);
815 * btrfs_attach_transaction() - catch the running transaction
817 * It is used when we want to commit the current the transaction, but
818 * don't want to start a new one.
820 * Note: If this function return -ENOENT, it just means there is no
821 * running transaction. But it is possible that the inactive transaction
822 * is still in the memory, not fully on disk. If you hope there is no
823 * inactive transaction in the fs when -ENOENT is returned, you should
825 * btrfs_attach_transaction_barrier()
827 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
829 return start_transaction(root, 0, TRANS_ATTACH,
830 BTRFS_RESERVE_NO_FLUSH, true);
834 * btrfs_attach_transaction_barrier() - catch the running transaction
836 * It is similar to the above function, the difference is this one
837 * will wait for all the inactive transactions until they fully
840 struct btrfs_trans_handle *
841 btrfs_attach_transaction_barrier(struct btrfs_root *root)
843 struct btrfs_trans_handle *trans;
845 trans = start_transaction(root, 0, TRANS_ATTACH,
846 BTRFS_RESERVE_NO_FLUSH, true);
847 if (trans == ERR_PTR(-ENOENT))
848 btrfs_wait_for_commit(root->fs_info, 0);
853 /* Wait for a transaction commit to reach at least the given state. */
854 static noinline void wait_for_commit(struct btrfs_transaction *commit,
855 const enum btrfs_trans_state min_state)
857 struct btrfs_fs_info *fs_info = commit->fs_info;
858 u64 transid = commit->transid;
862 wait_event(commit->commit_wait, commit->state >= min_state);
864 btrfs_put_transaction(commit);
866 if (min_state < TRANS_STATE_COMPLETED)
870 * A transaction isn't really completed until all of the
871 * previous transactions are completed, but with fsync we can
872 * end up with SUPER_COMMITTED transactions before a COMPLETED
873 * transaction. Wait for those.
876 spin_lock(&fs_info->trans_lock);
877 commit = list_first_entry_or_null(&fs_info->trans_list,
878 struct btrfs_transaction,
880 if (!commit || commit->transid > transid) {
881 spin_unlock(&fs_info->trans_lock);
884 refcount_inc(&commit->use_count);
886 spin_unlock(&fs_info->trans_lock);
890 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
892 struct btrfs_transaction *cur_trans = NULL, *t;
896 if (transid <= fs_info->last_trans_committed)
899 /* find specified transaction */
900 spin_lock(&fs_info->trans_lock);
901 list_for_each_entry(t, &fs_info->trans_list, list) {
902 if (t->transid == transid) {
904 refcount_inc(&cur_trans->use_count);
908 if (t->transid > transid) {
913 spin_unlock(&fs_info->trans_lock);
916 * The specified transaction doesn't exist, or we
917 * raced with btrfs_commit_transaction
920 if (transid > fs_info->last_trans_committed)
925 /* find newest transaction that is committing | committed */
926 spin_lock(&fs_info->trans_lock);
927 list_for_each_entry_reverse(t, &fs_info->trans_list,
929 if (t->state >= TRANS_STATE_COMMIT_START) {
930 if (t->state == TRANS_STATE_COMPLETED)
933 refcount_inc(&cur_trans->use_count);
937 spin_unlock(&fs_info->trans_lock);
939 goto out; /* nothing committing|committed */
942 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
943 btrfs_put_transaction(cur_trans);
948 void btrfs_throttle(struct btrfs_fs_info *fs_info)
950 wait_current_trans(fs_info);
953 static bool should_end_transaction(struct btrfs_trans_handle *trans)
955 struct btrfs_fs_info *fs_info = trans->fs_info;
957 if (btrfs_check_space_for_delayed_refs(fs_info))
960 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
963 bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
965 struct btrfs_transaction *cur_trans = trans->transaction;
967 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
968 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
971 return should_end_transaction(trans);
974 static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
977 struct btrfs_fs_info *fs_info = trans->fs_info;
979 if (!trans->block_rsv) {
980 ASSERT(!trans->bytes_reserved);
984 if (!trans->bytes_reserved)
987 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
988 trace_btrfs_space_reservation(fs_info, "transaction",
989 trans->transid, trans->bytes_reserved, 0);
990 btrfs_block_rsv_release(fs_info, trans->block_rsv,
991 trans->bytes_reserved, NULL);
992 trans->bytes_reserved = 0;
995 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
998 struct btrfs_fs_info *info = trans->fs_info;
999 struct btrfs_transaction *cur_trans = trans->transaction;
1002 if (refcount_read(&trans->use_count) > 1) {
1003 refcount_dec(&trans->use_count);
1004 trans->block_rsv = trans->orig_rsv;
1008 btrfs_trans_release_metadata(trans);
1009 trans->block_rsv = NULL;
1011 btrfs_create_pending_block_groups(trans);
1013 btrfs_trans_release_chunk_metadata(trans);
1015 if (trans->type & __TRANS_FREEZABLE)
1016 sb_end_intwrite(info->sb);
1018 WARN_ON(cur_trans != info->running_transaction);
1019 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1020 atomic_dec(&cur_trans->num_writers);
1021 extwriter_counter_dec(cur_trans, trans->type);
1023 cond_wake_up(&cur_trans->writer_wait);
1024 btrfs_put_transaction(cur_trans);
1026 if (current->journal_info == trans)
1027 current->journal_info = NULL;
1030 btrfs_run_delayed_iputs(info);
1032 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1033 wake_up_process(info->transaction_kthread);
1034 if (TRANS_ABORTED(trans))
1035 err = trans->aborted;
1040 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1044 int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1046 return __btrfs_end_transaction(trans, 0);
1049 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1051 return __btrfs_end_transaction(trans, 1);
1055 * when btree blocks are allocated, they have some corresponding bits set for
1056 * them in one of two extent_io trees. This is used to make sure all of
1057 * those extents are sent to disk but does not wait on them
1059 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1060 struct extent_io_tree *dirty_pages, int mark)
1064 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1065 struct extent_state *cached_state = NULL;
1069 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1070 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1071 mark, &cached_state)) {
1072 bool wait_writeback = false;
1074 err = convert_extent_bit(dirty_pages, start, end,
1076 mark, &cached_state);
1078 * convert_extent_bit can return -ENOMEM, which is most of the
1079 * time a temporary error. So when it happens, ignore the error
1080 * and wait for writeback of this range to finish - because we
1081 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1082 * to __btrfs_wait_marked_extents() would not know that
1083 * writeback for this range started and therefore wouldn't
1084 * wait for it to finish - we don't want to commit a
1085 * superblock that points to btree nodes/leafs for which
1086 * writeback hasn't finished yet (and without errors).
1087 * We cleanup any entries left in the io tree when committing
1088 * the transaction (through extent_io_tree_release()).
1090 if (err == -ENOMEM) {
1092 wait_writeback = true;
1095 err = filemap_fdatawrite_range(mapping, start, end);
1098 else if (wait_writeback)
1099 werr = filemap_fdatawait_range(mapping, start, end);
1100 free_extent_state(cached_state);
1101 cached_state = NULL;
1105 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1110 * when btree blocks are allocated, they have some corresponding bits set for
1111 * them in one of two extent_io trees. This is used to make sure all of
1112 * those extents are on disk for transaction or log commit. We wait
1113 * on all the pages and clear them from the dirty pages state tree
1115 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1116 struct extent_io_tree *dirty_pages)
1120 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1121 struct extent_state *cached_state = NULL;
1125 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1126 EXTENT_NEED_WAIT, &cached_state)) {
1128 * Ignore -ENOMEM errors returned by clear_extent_bit().
1129 * When committing the transaction, we'll remove any entries
1130 * left in the io tree. For a log commit, we don't remove them
1131 * after committing the log because the tree can be accessed
1132 * concurrently - we do it only at transaction commit time when
1133 * it's safe to do it (through extent_io_tree_release()).
1135 err = clear_extent_bit(dirty_pages, start, end,
1136 EXTENT_NEED_WAIT, 0, 0, &cached_state);
1140 err = filemap_fdatawait_range(mapping, start, end);
1143 free_extent_state(cached_state);
1144 cached_state = NULL;
1153 static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1154 struct extent_io_tree *dirty_pages)
1156 bool errors = false;
1159 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1160 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1168 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1170 struct btrfs_fs_info *fs_info = log_root->fs_info;
1171 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1172 bool errors = false;
1175 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1177 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1178 if ((mark & EXTENT_DIRTY) &&
1179 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1182 if ((mark & EXTENT_NEW) &&
1183 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1192 * When btree blocks are allocated the corresponding extents are marked dirty.
1193 * This function ensures such extents are persisted on disk for transaction or
1196 * @trans: transaction whose dirty pages we'd like to write
1198 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1202 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1203 struct btrfs_fs_info *fs_info = trans->fs_info;
1204 struct blk_plug plug;
1206 blk_start_plug(&plug);
1207 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1208 blk_finish_plug(&plug);
1209 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1211 extent_io_tree_release(&trans->transaction->dirty_pages);
1222 * this is used to update the root pointer in the tree of tree roots.
1224 * But, in the case of the extent allocation tree, updating the root
1225 * pointer may allocate blocks which may change the root of the extent
1228 * So, this loops and repeats and makes sure the cowonly root didn't
1229 * change while the root pointer was being updated in the metadata.
1231 static int update_cowonly_root(struct btrfs_trans_handle *trans,
1232 struct btrfs_root *root)
1235 u64 old_root_bytenr;
1237 struct btrfs_fs_info *fs_info = root->fs_info;
1238 struct btrfs_root *tree_root = fs_info->tree_root;
1240 old_root_used = btrfs_root_used(&root->root_item);
1243 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1244 if (old_root_bytenr == root->node->start &&
1245 old_root_used == btrfs_root_used(&root->root_item))
1248 btrfs_set_root_node(&root->root_item, root->node);
1249 ret = btrfs_update_root(trans, tree_root,
1255 old_root_used = btrfs_root_used(&root->root_item);
1262 * update all the cowonly tree roots on disk
1264 * The error handling in this function may not be obvious. Any of the
1265 * failures will cause the file system to go offline. We still need
1266 * to clean up the delayed refs.
1268 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1270 struct btrfs_fs_info *fs_info = trans->fs_info;
1271 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1272 struct list_head *io_bgs = &trans->transaction->io_bgs;
1273 struct list_head *next;
1274 struct extent_buffer *eb;
1278 * At this point no one can be using this transaction to modify any tree
1279 * and no one can start another transaction to modify any tree either.
1281 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1283 eb = btrfs_lock_root_node(fs_info->tree_root);
1284 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1285 0, &eb, BTRFS_NESTING_COW);
1286 btrfs_tree_unlock(eb);
1287 free_extent_buffer(eb);
1292 ret = btrfs_run_dev_stats(trans);
1295 ret = btrfs_run_dev_replace(trans);
1298 ret = btrfs_run_qgroups(trans);
1302 ret = btrfs_setup_space_cache(trans);
1307 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1308 struct btrfs_root *root;
1309 next = fs_info->dirty_cowonly_roots.next;
1310 list_del_init(next);
1311 root = list_entry(next, struct btrfs_root, dirty_list);
1312 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1314 list_add_tail(&root->dirty_list,
1315 &trans->transaction->switch_commits);
1316 ret = update_cowonly_root(trans, root);
1321 /* Now flush any delayed refs generated by updating all of the roots */
1322 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1326 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1327 ret = btrfs_write_dirty_block_groups(trans);
1332 * We're writing the dirty block groups, which could generate
1333 * delayed refs, which could generate more dirty block groups,
1334 * so we want to keep this flushing in this loop to make sure
1335 * everything gets run.
1337 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1342 if (!list_empty(&fs_info->dirty_cowonly_roots))
1345 /* Update dev-replace pointer once everything is committed */
1346 fs_info->dev_replace.committed_cursor_left =
1347 fs_info->dev_replace.cursor_left_last_write_of_item;
1353 * If we had a pending drop we need to see if there are any others left in our
1354 * dead roots list, and if not clear our bit and wake any waiters.
1356 void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1359 * We put the drop in progress roots at the front of the list, so if the
1360 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1363 spin_lock(&fs_info->trans_lock);
1364 if (!list_empty(&fs_info->dead_roots)) {
1365 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1368 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1369 spin_unlock(&fs_info->trans_lock);
1373 spin_unlock(&fs_info->trans_lock);
1375 btrfs_wake_unfinished_drop(fs_info);
1379 * dead roots are old snapshots that need to be deleted. This allocates
1380 * a dirty root struct and adds it into the list of dead roots that need to
1383 void btrfs_add_dead_root(struct btrfs_root *root)
1385 struct btrfs_fs_info *fs_info = root->fs_info;
1387 spin_lock(&fs_info->trans_lock);
1388 if (list_empty(&root->root_list)) {
1389 btrfs_grab_root(root);
1391 /* We want to process the partially complete drops first. */
1392 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1393 list_add(&root->root_list, &fs_info->dead_roots);
1395 list_add_tail(&root->root_list, &fs_info->dead_roots);
1397 spin_unlock(&fs_info->trans_lock);
1401 * Update each subvolume root and its relocation root, if it exists, in the tree
1402 * of tree roots. Also free log roots if they exist.
1404 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1406 struct btrfs_fs_info *fs_info = trans->fs_info;
1407 struct btrfs_root *gang[8];
1412 * At this point no one can be using this transaction to modify any tree
1413 * and no one can start another transaction to modify any tree either.
1415 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1417 spin_lock(&fs_info->fs_roots_radix_lock);
1419 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1422 BTRFS_ROOT_TRANS_TAG);
1425 for (i = 0; i < ret; i++) {
1426 struct btrfs_root *root = gang[i];
1430 * At this point we can neither have tasks logging inodes
1431 * from a root nor trying to commit a log tree.
1433 ASSERT(atomic_read(&root->log_writers) == 0);
1434 ASSERT(atomic_read(&root->log_commit[0]) == 0);
1435 ASSERT(atomic_read(&root->log_commit[1]) == 0);
1437 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1438 (unsigned long)root->root_key.objectid,
1439 BTRFS_ROOT_TRANS_TAG);
1440 spin_unlock(&fs_info->fs_roots_radix_lock);
1442 btrfs_free_log(trans, root);
1443 ret2 = btrfs_update_reloc_root(trans, root);
1447 /* see comments in should_cow_block() */
1448 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1449 smp_mb__after_atomic();
1451 if (root->commit_root != root->node) {
1452 list_add_tail(&root->dirty_list,
1453 &trans->transaction->switch_commits);
1454 btrfs_set_root_node(&root->root_item,
1458 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1463 spin_lock(&fs_info->fs_roots_radix_lock);
1464 btrfs_qgroup_free_meta_all_pertrans(root);
1467 spin_unlock(&fs_info->fs_roots_radix_lock);
1472 * defrag a given btree.
1473 * Every leaf in the btree is read and defragged.
1475 int btrfs_defrag_root(struct btrfs_root *root)
1477 struct btrfs_fs_info *info = root->fs_info;
1478 struct btrfs_trans_handle *trans;
1481 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1485 trans = btrfs_start_transaction(root, 0);
1486 if (IS_ERR(trans)) {
1487 ret = PTR_ERR(trans);
1491 ret = btrfs_defrag_leaves(trans, root);
1493 btrfs_end_transaction(trans);
1494 btrfs_btree_balance_dirty(info);
1497 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1500 if (btrfs_defrag_cancelled(info)) {
1501 btrfs_debug(info, "defrag_root cancelled");
1506 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1511 * Do all special snapshot related qgroup dirty hack.
1513 * Will do all needed qgroup inherit and dirty hack like switch commit
1514 * roots inside one transaction and write all btree into disk, to make
1517 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1518 struct btrfs_root *src,
1519 struct btrfs_root *parent,
1520 struct btrfs_qgroup_inherit *inherit,
1523 struct btrfs_fs_info *fs_info = src->fs_info;
1527 * Save some performance in the case that qgroups are not
1528 * enabled. If this check races with the ioctl, rescan will
1531 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1535 * Ensure dirty @src will be committed. Or, after coming
1536 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1537 * recorded root will never be updated again, causing an outdated root
1540 ret = record_root_in_trans(trans, src, 1);
1545 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1546 * src root, so we must run the delayed refs here.
1548 * However this isn't particularly fool proof, because there's no
1549 * synchronization keeping us from changing the tree after this point
1550 * before we do the qgroup_inherit, or even from making changes while
1551 * we're doing the qgroup_inherit. But that's a problem for the future,
1552 * for now flush the delayed refs to narrow the race window where the
1553 * qgroup counters could end up wrong.
1555 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1557 btrfs_abort_transaction(trans, ret);
1561 ret = commit_fs_roots(trans);
1564 ret = btrfs_qgroup_account_extents(trans);
1568 /* Now qgroup are all updated, we can inherit it to new qgroups */
1569 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1575 * Now we do a simplified commit transaction, which will:
1576 * 1) commit all subvolume and extent tree
1577 * To ensure all subvolume and extent tree have a valid
1578 * commit_root to accounting later insert_dir_item()
1579 * 2) write all btree blocks onto disk
1580 * This is to make sure later btree modification will be cowed
1581 * Or commit_root can be populated and cause wrong qgroup numbers
1582 * In this simplified commit, we don't really care about other trees
1583 * like chunk and root tree, as they won't affect qgroup.
1584 * And we don't write super to avoid half committed status.
1586 ret = commit_cowonly_roots(trans);
1589 switch_commit_roots(trans);
1590 ret = btrfs_write_and_wait_transaction(trans);
1592 btrfs_handle_fs_error(fs_info, ret,
1593 "Error while writing out transaction for qgroup");
1597 * Force parent root to be updated, as we recorded it before so its
1598 * last_trans == cur_transid.
1599 * Or it won't be committed again onto disk after later
1603 ret = record_root_in_trans(trans, parent, 1);
1608 * new snapshots need to be created at a very specific time in the
1609 * transaction commit. This does the actual creation.
1612 * If the error which may affect the commitment of the current transaction
1613 * happens, we should return the error number. If the error which just affect
1614 * the creation of the pending snapshots, just return 0.
1616 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1617 struct btrfs_pending_snapshot *pending)
1620 struct btrfs_fs_info *fs_info = trans->fs_info;
1621 struct btrfs_key key;
1622 struct btrfs_root_item *new_root_item;
1623 struct btrfs_root *tree_root = fs_info->tree_root;
1624 struct btrfs_root *root = pending->root;
1625 struct btrfs_root *parent_root;
1626 struct btrfs_block_rsv *rsv;
1627 struct inode *parent_inode;
1628 struct btrfs_path *path;
1629 struct btrfs_dir_item *dir_item;
1630 struct dentry *dentry;
1631 struct extent_buffer *tmp;
1632 struct extent_buffer *old;
1633 struct timespec64 cur_time;
1640 ASSERT(pending->path);
1641 path = pending->path;
1643 ASSERT(pending->root_item);
1644 new_root_item = pending->root_item;
1646 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1648 goto no_free_objectid;
1651 * Make qgroup to skip current new snapshot's qgroupid, as it is
1652 * accounted by later btrfs_qgroup_inherit().
1654 btrfs_set_skip_qgroup(trans, objectid);
1656 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1658 if (to_reserve > 0) {
1659 pending->error = btrfs_block_rsv_add(fs_info,
1660 &pending->block_rsv,
1662 BTRFS_RESERVE_NO_FLUSH);
1664 goto clear_skip_qgroup;
1667 key.objectid = objectid;
1668 key.offset = (u64)-1;
1669 key.type = BTRFS_ROOT_ITEM_KEY;
1671 rsv = trans->block_rsv;
1672 trans->block_rsv = &pending->block_rsv;
1673 trans->bytes_reserved = trans->block_rsv->reserved;
1674 trace_btrfs_space_reservation(fs_info, "transaction",
1676 trans->bytes_reserved, 1);
1677 dentry = pending->dentry;
1678 parent_inode = pending->dir;
1679 parent_root = BTRFS_I(parent_inode)->root;
1680 ret = record_root_in_trans(trans, parent_root, 0);
1683 cur_time = current_time(parent_inode);
1686 * insert the directory item
1688 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1689 BUG_ON(ret); /* -ENOMEM */
1691 /* check if there is a file/dir which has the same name. */
1692 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1693 btrfs_ino(BTRFS_I(parent_inode)),
1694 dentry->d_name.name,
1695 dentry->d_name.len, 0);
1696 if (dir_item != NULL && !IS_ERR(dir_item)) {
1697 pending->error = -EEXIST;
1698 goto dir_item_existed;
1699 } else if (IS_ERR(dir_item)) {
1700 ret = PTR_ERR(dir_item);
1701 btrfs_abort_transaction(trans, ret);
1704 btrfs_release_path(path);
1707 * pull in the delayed directory update
1708 * and the delayed inode item
1709 * otherwise we corrupt the FS during
1712 ret = btrfs_run_delayed_items(trans);
1713 if (ret) { /* Transaction aborted */
1714 btrfs_abort_transaction(trans, ret);
1718 ret = record_root_in_trans(trans, root, 0);
1720 btrfs_abort_transaction(trans, ret);
1723 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1724 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1725 btrfs_check_and_init_root_item(new_root_item);
1727 root_flags = btrfs_root_flags(new_root_item);
1728 if (pending->readonly)
1729 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1731 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1732 btrfs_set_root_flags(new_root_item, root_flags);
1734 btrfs_set_root_generation_v2(new_root_item,
1736 generate_random_guid(new_root_item->uuid);
1737 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1739 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1740 memset(new_root_item->received_uuid, 0,
1741 sizeof(new_root_item->received_uuid));
1742 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1743 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1744 btrfs_set_root_stransid(new_root_item, 0);
1745 btrfs_set_root_rtransid(new_root_item, 0);
1747 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1748 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1749 btrfs_set_root_otransid(new_root_item, trans->transid);
1751 old = btrfs_lock_root_node(root);
1752 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1755 btrfs_tree_unlock(old);
1756 free_extent_buffer(old);
1757 btrfs_abort_transaction(trans, ret);
1761 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1762 /* clean up in any case */
1763 btrfs_tree_unlock(old);
1764 free_extent_buffer(old);
1766 btrfs_abort_transaction(trans, ret);
1769 /* see comments in should_cow_block() */
1770 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1773 btrfs_set_root_node(new_root_item, tmp);
1774 /* record when the snapshot was created in key.offset */
1775 key.offset = trans->transid;
1776 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1777 btrfs_tree_unlock(tmp);
1778 free_extent_buffer(tmp);
1780 btrfs_abort_transaction(trans, ret);
1785 * insert root back/forward references
1787 ret = btrfs_add_root_ref(trans, objectid,
1788 parent_root->root_key.objectid,
1789 btrfs_ino(BTRFS_I(parent_inode)), index,
1790 dentry->d_name.name, dentry->d_name.len);
1792 btrfs_abort_transaction(trans, ret);
1796 key.offset = (u64)-1;
1797 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1798 if (IS_ERR(pending->snap)) {
1799 ret = PTR_ERR(pending->snap);
1800 pending->snap = NULL;
1801 btrfs_abort_transaction(trans, ret);
1805 ret = btrfs_reloc_post_snapshot(trans, pending);
1807 btrfs_abort_transaction(trans, ret);
1812 * Do special qgroup accounting for snapshot, as we do some qgroup
1813 * snapshot hack to do fast snapshot.
1814 * To co-operate with that hack, we do hack again.
1815 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1817 ret = qgroup_account_snapshot(trans, root, parent_root,
1818 pending->inherit, objectid);
1822 ret = btrfs_insert_dir_item(trans, dentry->d_name.name,
1823 dentry->d_name.len, BTRFS_I(parent_inode),
1824 &key, BTRFS_FT_DIR, index);
1825 /* We have check then name at the beginning, so it is impossible. */
1826 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1828 btrfs_abort_transaction(trans, ret);
1832 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1833 dentry->d_name.len * 2);
1834 parent_inode->i_mtime = parent_inode->i_ctime =
1835 current_time(parent_inode);
1836 ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
1838 btrfs_abort_transaction(trans, ret);
1841 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1842 BTRFS_UUID_KEY_SUBVOL,
1845 btrfs_abort_transaction(trans, ret);
1848 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1849 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1850 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1852 if (ret && ret != -EEXIST) {
1853 btrfs_abort_transaction(trans, ret);
1859 pending->error = ret;
1861 trans->block_rsv = rsv;
1862 trans->bytes_reserved = 0;
1864 btrfs_clear_skip_qgroup(trans);
1866 kfree(new_root_item);
1867 pending->root_item = NULL;
1868 btrfs_free_path(path);
1869 pending->path = NULL;
1875 * create all the snapshots we've scheduled for creation
1877 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1879 struct btrfs_pending_snapshot *pending, *next;
1880 struct list_head *head = &trans->transaction->pending_snapshots;
1883 list_for_each_entry_safe(pending, next, head, list) {
1884 list_del(&pending->list);
1885 ret = create_pending_snapshot(trans, pending);
1892 static void update_super_roots(struct btrfs_fs_info *fs_info)
1894 struct btrfs_root_item *root_item;
1895 struct btrfs_super_block *super;
1897 super = fs_info->super_copy;
1899 root_item = &fs_info->chunk_root->root_item;
1900 super->chunk_root = root_item->bytenr;
1901 super->chunk_root_generation = root_item->generation;
1902 super->chunk_root_level = root_item->level;
1904 root_item = &fs_info->tree_root->root_item;
1905 super->root = root_item->bytenr;
1906 super->generation = root_item->generation;
1907 super->root_level = root_item->level;
1908 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1909 super->cache_generation = root_item->generation;
1910 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1911 super->cache_generation = 0;
1912 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1913 super->uuid_tree_generation = root_item->generation;
1915 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
1916 root_item = &fs_info->block_group_root->root_item;
1918 super->block_group_root = root_item->bytenr;
1919 super->block_group_root_generation = root_item->generation;
1920 super->block_group_root_level = root_item->level;
1924 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1926 struct btrfs_transaction *trans;
1929 spin_lock(&info->trans_lock);
1930 trans = info->running_transaction;
1932 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1933 spin_unlock(&info->trans_lock);
1937 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1939 struct btrfs_transaction *trans;
1942 spin_lock(&info->trans_lock);
1943 trans = info->running_transaction;
1945 ret = is_transaction_blocked(trans);
1946 spin_unlock(&info->trans_lock);
1950 void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1952 struct btrfs_fs_info *fs_info = trans->fs_info;
1953 struct btrfs_transaction *cur_trans;
1955 /* Kick the transaction kthread. */
1956 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1957 wake_up_process(fs_info->transaction_kthread);
1959 /* take transaction reference */
1960 cur_trans = trans->transaction;
1961 refcount_inc(&cur_trans->use_count);
1963 btrfs_end_transaction(trans);
1966 * Wait for the current transaction commit to start and block
1967 * subsequent transaction joins
1969 wait_event(fs_info->transaction_blocked_wait,
1970 cur_trans->state >= TRANS_STATE_COMMIT_START ||
1971 TRANS_ABORTED(cur_trans));
1972 btrfs_put_transaction(cur_trans);
1975 static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1977 struct btrfs_fs_info *fs_info = trans->fs_info;
1978 struct btrfs_transaction *cur_trans = trans->transaction;
1980 WARN_ON(refcount_read(&trans->use_count) > 1);
1982 btrfs_abort_transaction(trans, err);
1984 spin_lock(&fs_info->trans_lock);
1987 * If the transaction is removed from the list, it means this
1988 * transaction has been committed successfully, so it is impossible
1989 * to call the cleanup function.
1991 BUG_ON(list_empty(&cur_trans->list));
1993 if (cur_trans == fs_info->running_transaction) {
1994 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1995 spin_unlock(&fs_info->trans_lock);
1996 wait_event(cur_trans->writer_wait,
1997 atomic_read(&cur_trans->num_writers) == 1);
1999 spin_lock(&fs_info->trans_lock);
2003 * Now that we know no one else is still using the transaction we can
2004 * remove the transaction from the list of transactions. This avoids
2005 * the transaction kthread from cleaning up the transaction while some
2006 * other task is still using it, which could result in a use-after-free
2007 * on things like log trees, as it forces the transaction kthread to
2008 * wait for this transaction to be cleaned up by us.
2010 list_del_init(&cur_trans->list);
2012 spin_unlock(&fs_info->trans_lock);
2014 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
2016 spin_lock(&fs_info->trans_lock);
2017 if (cur_trans == fs_info->running_transaction)
2018 fs_info->running_transaction = NULL;
2019 spin_unlock(&fs_info->trans_lock);
2021 if (trans->type & __TRANS_FREEZABLE)
2022 sb_end_intwrite(fs_info->sb);
2023 btrfs_put_transaction(cur_trans);
2024 btrfs_put_transaction(cur_trans);
2026 trace_btrfs_transaction_commit(fs_info);
2028 if (current->journal_info == trans)
2029 current->journal_info = NULL;
2030 btrfs_scrub_cancel(fs_info);
2032 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2036 * Release reserved delayed ref space of all pending block groups of the
2037 * transaction and remove them from the list
2039 static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2041 struct btrfs_fs_info *fs_info = trans->fs_info;
2042 struct btrfs_block_group *block_group, *tmp;
2044 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2045 btrfs_delayed_refs_rsv_release(fs_info, 1);
2046 list_del_init(&block_group->bg_list);
2050 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2053 * We use try_to_writeback_inodes_sb() here because if we used
2054 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2055 * Currently are holding the fs freeze lock, if we do an async flush
2056 * we'll do btrfs_join_transaction() and deadlock because we need to
2057 * wait for the fs freeze lock. Using the direct flushing we benefit
2058 * from already being in a transaction and our join_transaction doesn't
2059 * have to re-take the fs freeze lock.
2061 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2062 * if it can read lock sb->s_umount. It will always be able to lock it,
2063 * except when the filesystem is being unmounted or being frozen, but in
2064 * those cases sync_filesystem() is called, which results in calling
2065 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2066 * Note that we don't call writeback_inodes_sb() directly, because it
2067 * will emit a warning if sb->s_umount is not locked.
2069 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2070 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2074 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2076 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2077 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2081 * Add a pending snapshot associated with the given transaction handle to the
2082 * respective handle. This must be called after the transaction commit started
2083 * and while holding fs_info->trans_lock.
2084 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2085 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2088 static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2090 struct btrfs_transaction *cur_trans = trans->transaction;
2092 if (!trans->pending_snapshot)
2095 lockdep_assert_held(&trans->fs_info->trans_lock);
2096 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START);
2098 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2101 int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2103 struct btrfs_fs_info *fs_info = trans->fs_info;
2104 struct btrfs_transaction *cur_trans = trans->transaction;
2105 struct btrfs_transaction *prev_trans = NULL;
2108 ASSERT(refcount_read(&trans->use_count) == 1);
2110 /* Stop the commit early if ->aborted is set */
2111 if (TRANS_ABORTED(cur_trans)) {
2112 ret = cur_trans->aborted;
2113 btrfs_end_transaction(trans);
2117 btrfs_trans_release_metadata(trans);
2118 trans->block_rsv = NULL;
2121 * We only want one transaction commit doing the flushing so we do not
2122 * waste a bunch of time on lock contention on the extent root node.
2124 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2125 &cur_trans->delayed_refs.flags)) {
2127 * Make a pass through all the delayed refs we have so far.
2128 * Any running threads may add more while we are here.
2130 ret = btrfs_run_delayed_refs(trans, 0);
2132 btrfs_end_transaction(trans);
2137 btrfs_create_pending_block_groups(trans);
2139 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2142 /* this mutex is also taken before trying to set
2143 * block groups readonly. We need to make sure
2144 * that nobody has set a block group readonly
2145 * after a extents from that block group have been
2146 * allocated for cache files. btrfs_set_block_group_ro
2147 * will wait for the transaction to commit if it
2148 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2150 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2151 * only one process starts all the block group IO. It wouldn't
2152 * hurt to have more than one go through, but there's no
2153 * real advantage to it either.
2155 mutex_lock(&fs_info->ro_block_group_mutex);
2156 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2159 mutex_unlock(&fs_info->ro_block_group_mutex);
2162 ret = btrfs_start_dirty_block_groups(trans);
2164 btrfs_end_transaction(trans);
2170 spin_lock(&fs_info->trans_lock);
2171 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2172 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2174 add_pending_snapshot(trans);
2176 spin_unlock(&fs_info->trans_lock);
2177 refcount_inc(&cur_trans->use_count);
2179 if (trans->in_fsync)
2180 want_state = TRANS_STATE_SUPER_COMMITTED;
2181 ret = btrfs_end_transaction(trans);
2182 wait_for_commit(cur_trans, want_state);
2184 if (TRANS_ABORTED(cur_trans))
2185 ret = cur_trans->aborted;
2187 btrfs_put_transaction(cur_trans);
2192 cur_trans->state = TRANS_STATE_COMMIT_START;
2193 wake_up(&fs_info->transaction_blocked_wait);
2195 if (cur_trans->list.prev != &fs_info->trans_list) {
2196 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2198 if (trans->in_fsync)
2199 want_state = TRANS_STATE_SUPER_COMMITTED;
2201 prev_trans = list_entry(cur_trans->list.prev,
2202 struct btrfs_transaction, list);
2203 if (prev_trans->state < want_state) {
2204 refcount_inc(&prev_trans->use_count);
2205 spin_unlock(&fs_info->trans_lock);
2207 wait_for_commit(prev_trans, want_state);
2209 ret = READ_ONCE(prev_trans->aborted);
2211 btrfs_put_transaction(prev_trans);
2213 goto cleanup_transaction;
2215 spin_unlock(&fs_info->trans_lock);
2218 spin_unlock(&fs_info->trans_lock);
2220 * The previous transaction was aborted and was already removed
2221 * from the list of transactions at fs_info->trans_list. So we
2222 * abort to prevent writing a new superblock that reflects a
2223 * corrupt state (pointing to trees with unwritten nodes/leafs).
2225 if (BTRFS_FS_ERROR(fs_info)) {
2227 goto cleanup_transaction;
2231 extwriter_counter_dec(cur_trans, trans->type);
2233 ret = btrfs_start_delalloc_flush(fs_info);
2235 goto cleanup_transaction;
2237 ret = btrfs_run_delayed_items(trans);
2239 goto cleanup_transaction;
2241 wait_event(cur_trans->writer_wait,
2242 extwriter_counter_read(cur_trans) == 0);
2244 /* some pending stuffs might be added after the previous flush. */
2245 ret = btrfs_run_delayed_items(trans);
2247 goto cleanup_transaction;
2249 btrfs_wait_delalloc_flush(fs_info);
2252 * Wait for all ordered extents started by a fast fsync that joined this
2253 * transaction. Otherwise if this transaction commits before the ordered
2254 * extents complete we lose logged data after a power failure.
2256 wait_event(cur_trans->pending_wait,
2257 atomic_read(&cur_trans->pending_ordered) == 0);
2259 btrfs_scrub_pause(fs_info);
2261 * Ok now we need to make sure to block out any other joins while we
2262 * commit the transaction. We could have started a join before setting
2263 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2265 spin_lock(&fs_info->trans_lock);
2266 add_pending_snapshot(trans);
2267 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2268 spin_unlock(&fs_info->trans_lock);
2269 wait_event(cur_trans->writer_wait,
2270 atomic_read(&cur_trans->num_writers) == 1);
2273 * We've started the commit, clear the flag in case we were triggered to
2274 * do an async commit but somebody else started before the transaction
2275 * kthread could do the work.
2277 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2279 if (TRANS_ABORTED(cur_trans)) {
2280 ret = cur_trans->aborted;
2281 goto scrub_continue;
2284 * the reloc mutex makes sure that we stop
2285 * the balancing code from coming in and moving
2286 * extents around in the middle of the commit
2288 mutex_lock(&fs_info->reloc_mutex);
2291 * We needn't worry about the delayed items because we will
2292 * deal with them in create_pending_snapshot(), which is the
2293 * core function of the snapshot creation.
2295 ret = create_pending_snapshots(trans);
2300 * We insert the dir indexes of the snapshots and update the inode
2301 * of the snapshots' parents after the snapshot creation, so there
2302 * are some delayed items which are not dealt with. Now deal with
2305 * We needn't worry that this operation will corrupt the snapshots,
2306 * because all the tree which are snapshoted will be forced to COW
2307 * the nodes and leaves.
2309 ret = btrfs_run_delayed_items(trans);
2313 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2318 * make sure none of the code above managed to slip in a
2321 btrfs_assert_delayed_root_empty(fs_info);
2323 WARN_ON(cur_trans != trans->transaction);
2325 ret = commit_fs_roots(trans);
2330 * Since the transaction is done, we can apply the pending changes
2331 * before the next transaction.
2333 btrfs_apply_pending_changes(fs_info);
2335 /* commit_fs_roots gets rid of all the tree log roots, it is now
2336 * safe to free the root of tree log roots
2338 btrfs_free_log_root_tree(trans, fs_info);
2341 * Since fs roots are all committed, we can get a quite accurate
2342 * new_roots. So let's do quota accounting.
2344 ret = btrfs_qgroup_account_extents(trans);
2348 ret = commit_cowonly_roots(trans);
2353 * The tasks which save the space cache and inode cache may also
2354 * update ->aborted, check it.
2356 if (TRANS_ABORTED(cur_trans)) {
2357 ret = cur_trans->aborted;
2361 cur_trans = fs_info->running_transaction;
2363 btrfs_set_root_node(&fs_info->tree_root->root_item,
2364 fs_info->tree_root->node);
2365 list_add_tail(&fs_info->tree_root->dirty_list,
2366 &cur_trans->switch_commits);
2368 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2369 fs_info->chunk_root->node);
2370 list_add_tail(&fs_info->chunk_root->dirty_list,
2371 &cur_trans->switch_commits);
2373 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2374 btrfs_set_root_node(&fs_info->block_group_root->root_item,
2375 fs_info->block_group_root->node);
2376 list_add_tail(&fs_info->block_group_root->dirty_list,
2377 &cur_trans->switch_commits);
2380 switch_commit_roots(trans);
2382 ASSERT(list_empty(&cur_trans->dirty_bgs));
2383 ASSERT(list_empty(&cur_trans->io_bgs));
2384 update_super_roots(fs_info);
2386 btrfs_set_super_log_root(fs_info->super_copy, 0);
2387 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2388 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2389 sizeof(*fs_info->super_copy));
2391 btrfs_commit_device_sizes(cur_trans);
2393 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2394 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2396 btrfs_trans_release_chunk_metadata(trans);
2399 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2400 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2401 * make sure that before we commit our superblock, no other task can
2402 * start a new transaction and commit a log tree before we commit our
2403 * superblock. Anyone trying to commit a log tree locks this mutex before
2404 * writing its superblock.
2406 mutex_lock(&fs_info->tree_log_mutex);
2408 spin_lock(&fs_info->trans_lock);
2409 cur_trans->state = TRANS_STATE_UNBLOCKED;
2410 fs_info->running_transaction = NULL;
2411 spin_unlock(&fs_info->trans_lock);
2412 mutex_unlock(&fs_info->reloc_mutex);
2414 wake_up(&fs_info->transaction_wait);
2416 ret = btrfs_write_and_wait_transaction(trans);
2418 btrfs_handle_fs_error(fs_info, ret,
2419 "Error while writing out transaction");
2420 mutex_unlock(&fs_info->tree_log_mutex);
2421 goto scrub_continue;
2425 * At this point, we should have written all the tree blocks allocated
2426 * in this transaction. So it's now safe to free the redirtyied extent
2429 btrfs_free_redirty_list(cur_trans);
2431 ret = write_all_supers(fs_info, 0);
2433 * the super is written, we can safely allow the tree-loggers
2434 * to go about their business
2436 mutex_unlock(&fs_info->tree_log_mutex);
2438 goto scrub_continue;
2441 * We needn't acquire the lock here because there is no other task
2442 * which can change it.
2444 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2445 wake_up(&cur_trans->commit_wait);
2447 btrfs_finish_extent_commit(trans);
2449 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2450 btrfs_clear_space_info_full(fs_info);
2452 fs_info->last_trans_committed = cur_trans->transid;
2454 * We needn't acquire the lock here because there is no other task
2455 * which can change it.
2457 cur_trans->state = TRANS_STATE_COMPLETED;
2458 wake_up(&cur_trans->commit_wait);
2460 spin_lock(&fs_info->trans_lock);
2461 list_del_init(&cur_trans->list);
2462 spin_unlock(&fs_info->trans_lock);
2464 btrfs_put_transaction(cur_trans);
2465 btrfs_put_transaction(cur_trans);
2467 if (trans->type & __TRANS_FREEZABLE)
2468 sb_end_intwrite(fs_info->sb);
2470 trace_btrfs_transaction_commit(fs_info);
2472 btrfs_scrub_continue(fs_info);
2474 if (current->journal_info == trans)
2475 current->journal_info = NULL;
2477 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2482 mutex_unlock(&fs_info->reloc_mutex);
2484 btrfs_scrub_continue(fs_info);
2485 cleanup_transaction:
2486 btrfs_trans_release_metadata(trans);
2487 btrfs_cleanup_pending_block_groups(trans);
2488 btrfs_trans_release_chunk_metadata(trans);
2489 trans->block_rsv = NULL;
2490 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2491 if (current->journal_info == trans)
2492 current->journal_info = NULL;
2493 cleanup_transaction(trans, ret);
2499 * return < 0 if error
2500 * 0 if there are no more dead_roots at the time of call
2501 * 1 there are more to be processed, call me again
2503 * The return value indicates there are certainly more snapshots to delete, but
2504 * if there comes a new one during processing, it may return 0. We don't mind,
2505 * because btrfs_commit_super will poke cleaner thread and it will process it a
2506 * few seconds later.
2508 int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2510 struct btrfs_root *root;
2513 spin_lock(&fs_info->trans_lock);
2514 if (list_empty(&fs_info->dead_roots)) {
2515 spin_unlock(&fs_info->trans_lock);
2518 root = list_first_entry(&fs_info->dead_roots,
2519 struct btrfs_root, root_list);
2520 list_del_init(&root->root_list);
2521 spin_unlock(&fs_info->trans_lock);
2523 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2525 btrfs_kill_all_delayed_nodes(root);
2527 if (btrfs_header_backref_rev(root->node) <
2528 BTRFS_MIXED_BACKREF_REV)
2529 ret = btrfs_drop_snapshot(root, 0, 0);
2531 ret = btrfs_drop_snapshot(root, 1, 0);
2533 btrfs_put_root(root);
2534 return (ret < 0) ? 0 : 1;
2537 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2542 prev = xchg(&fs_info->pending_changes, 0);
2546 bit = 1 << BTRFS_PENDING_COMMIT;
2548 btrfs_debug(fs_info, "pending commit done");
2553 "unknown pending changes left 0x%lx, ignoring", prev);