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>
15 #include "transaction.h"
18 #include "inode-map.h"
20 #include "dev-replace.h"
23 #define BTRFS_ROOT_TRANS_TAG 0
25 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
26 [TRANS_STATE_RUNNING] = 0U,
27 [TRANS_STATE_BLOCKED] = __TRANS_START,
28 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
29 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
32 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
36 [TRANS_STATE_COMPLETED] = (__TRANS_START |
42 void btrfs_put_transaction(struct btrfs_transaction *transaction)
44 WARN_ON(refcount_read(&transaction->use_count) == 0);
45 if (refcount_dec_and_test(&transaction->use_count)) {
46 BUG_ON(!list_empty(&transaction->list));
47 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
48 if (transaction->delayed_refs.pending_csums)
49 btrfs_err(transaction->fs_info,
50 "pending csums is %llu",
51 transaction->delayed_refs.pending_csums);
52 while (!list_empty(&transaction->pending_chunks)) {
53 struct extent_map *em;
55 em = list_first_entry(&transaction->pending_chunks,
56 struct extent_map, list);
57 list_del_init(&em->list);
61 * If any block groups are found in ->deleted_bgs then it's
62 * because the transaction was aborted and a commit did not
63 * happen (things failed before writing the new superblock
64 * and calling btrfs_finish_extent_commit()), so we can not
65 * discard the physical locations of the block groups.
67 while (!list_empty(&transaction->deleted_bgs)) {
68 struct btrfs_block_group_cache *cache;
70 cache = list_first_entry(&transaction->deleted_bgs,
71 struct btrfs_block_group_cache,
73 list_del_init(&cache->bg_list);
74 btrfs_put_block_group_trimming(cache);
75 btrfs_put_block_group(cache);
81 static void clear_btree_io_tree(struct extent_io_tree *tree)
83 spin_lock(&tree->lock);
85 * Do a single barrier for the waitqueue_active check here, the state
86 * of the waitqueue should not change once clear_btree_io_tree is
90 while (!RB_EMPTY_ROOT(&tree->state)) {
92 struct extent_state *state;
94 node = rb_first(&tree->state);
95 state = rb_entry(node, struct extent_state, rb_node);
96 rb_erase(&state->rb_node, &tree->state);
97 RB_CLEAR_NODE(&state->rb_node);
99 * btree io trees aren't supposed to have tasks waiting for
100 * changes in the flags of extent states ever.
102 ASSERT(!waitqueue_active(&state->wq));
103 free_extent_state(state);
105 cond_resched_lock(&tree->lock);
107 spin_unlock(&tree->lock);
110 static noinline void switch_commit_roots(struct btrfs_transaction *trans)
112 struct btrfs_fs_info *fs_info = trans->fs_info;
113 struct btrfs_root *root, *tmp;
115 down_write(&fs_info->commit_root_sem);
116 list_for_each_entry_safe(root, tmp, &trans->switch_commits,
118 list_del_init(&root->dirty_list);
119 free_extent_buffer(root->commit_root);
120 root->commit_root = btrfs_root_node(root);
121 if (is_fstree(root->objectid))
122 btrfs_unpin_free_ino(root);
123 clear_btree_io_tree(&root->dirty_log_pages);
126 /* We can free old roots now. */
127 spin_lock(&trans->dropped_roots_lock);
128 while (!list_empty(&trans->dropped_roots)) {
129 root = list_first_entry(&trans->dropped_roots,
130 struct btrfs_root, root_list);
131 list_del_init(&root->root_list);
132 spin_unlock(&trans->dropped_roots_lock);
133 btrfs_drop_and_free_fs_root(fs_info, root);
134 spin_lock(&trans->dropped_roots_lock);
136 spin_unlock(&trans->dropped_roots_lock);
137 up_write(&fs_info->commit_root_sem);
140 static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
143 if (type & TRANS_EXTWRITERS)
144 atomic_inc(&trans->num_extwriters);
147 static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
150 if (type & TRANS_EXTWRITERS)
151 atomic_dec(&trans->num_extwriters);
154 static inline void extwriter_counter_init(struct btrfs_transaction *trans,
157 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
160 static inline int extwriter_counter_read(struct btrfs_transaction *trans)
162 return atomic_read(&trans->num_extwriters);
166 * either allocate a new transaction or hop into the existing one
168 static noinline int join_transaction(struct btrfs_fs_info *fs_info,
171 struct btrfs_transaction *cur_trans;
173 spin_lock(&fs_info->trans_lock);
175 /* The file system has been taken offline. No new transactions. */
176 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
177 spin_unlock(&fs_info->trans_lock);
181 cur_trans = fs_info->running_transaction;
183 if (cur_trans->aborted) {
184 spin_unlock(&fs_info->trans_lock);
185 return cur_trans->aborted;
187 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
188 spin_unlock(&fs_info->trans_lock);
191 refcount_inc(&cur_trans->use_count);
192 atomic_inc(&cur_trans->num_writers);
193 extwriter_counter_inc(cur_trans, type);
194 spin_unlock(&fs_info->trans_lock);
197 spin_unlock(&fs_info->trans_lock);
200 * If we are ATTACH, we just want to catch the current transaction,
201 * and commit it. If there is no transaction, just return ENOENT.
203 if (type == TRANS_ATTACH)
207 * JOIN_NOLOCK only happens during the transaction commit, so
208 * it is impossible that ->running_transaction is NULL
210 BUG_ON(type == TRANS_JOIN_NOLOCK);
212 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
216 spin_lock(&fs_info->trans_lock);
217 if (fs_info->running_transaction) {
219 * someone started a transaction after we unlocked. Make sure
220 * to redo the checks above
224 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
225 spin_unlock(&fs_info->trans_lock);
230 cur_trans->fs_info = fs_info;
231 atomic_set(&cur_trans->num_writers, 1);
232 extwriter_counter_init(cur_trans, type);
233 init_waitqueue_head(&cur_trans->writer_wait);
234 init_waitqueue_head(&cur_trans->commit_wait);
235 init_waitqueue_head(&cur_trans->pending_wait);
236 cur_trans->state = TRANS_STATE_RUNNING;
238 * One for this trans handle, one so it will live on until we
239 * commit the transaction.
241 refcount_set(&cur_trans->use_count, 2);
242 atomic_set(&cur_trans->pending_ordered, 0);
243 cur_trans->flags = 0;
244 cur_trans->start_time = get_seconds();
246 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
248 cur_trans->delayed_refs.href_root = RB_ROOT;
249 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
250 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
253 * although the tree mod log is per file system and not per transaction,
254 * the log must never go across transaction boundaries.
257 if (!list_empty(&fs_info->tree_mod_seq_list))
258 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
259 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
260 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
261 atomic64_set(&fs_info->tree_mod_seq, 0);
263 spin_lock_init(&cur_trans->delayed_refs.lock);
265 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
266 INIT_LIST_HEAD(&cur_trans->pending_chunks);
267 INIT_LIST_HEAD(&cur_trans->switch_commits);
268 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
269 INIT_LIST_HEAD(&cur_trans->io_bgs);
270 INIT_LIST_HEAD(&cur_trans->dropped_roots);
271 mutex_init(&cur_trans->cache_write_mutex);
272 cur_trans->num_dirty_bgs = 0;
273 spin_lock_init(&cur_trans->dirty_bgs_lock);
274 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
275 spin_lock_init(&cur_trans->dropped_roots_lock);
276 list_add_tail(&cur_trans->list, &fs_info->trans_list);
277 extent_io_tree_init(&cur_trans->dirty_pages,
278 fs_info->btree_inode);
279 fs_info->generation++;
280 cur_trans->transid = fs_info->generation;
281 fs_info->running_transaction = cur_trans;
282 cur_trans->aborted = 0;
283 spin_unlock(&fs_info->trans_lock);
289 * this does all the record keeping required to make sure that a reference
290 * counted root is properly recorded in a given transaction. This is required
291 * to make sure the old root from before we joined the transaction is deleted
292 * when the transaction commits
294 static int record_root_in_trans(struct btrfs_trans_handle *trans,
295 struct btrfs_root *root,
298 struct btrfs_fs_info *fs_info = root->fs_info;
300 if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
301 root->last_trans < trans->transid) || force) {
302 WARN_ON(root == fs_info->extent_root);
303 WARN_ON(!force && root->commit_root != root->node);
306 * see below for IN_TRANS_SETUP usage rules
307 * we have the reloc mutex held now, so there
308 * is only one writer in this function
310 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
312 /* make sure readers find IN_TRANS_SETUP before
313 * they find our root->last_trans update
317 spin_lock(&fs_info->fs_roots_radix_lock);
318 if (root->last_trans == trans->transid && !force) {
319 spin_unlock(&fs_info->fs_roots_radix_lock);
322 radix_tree_tag_set(&fs_info->fs_roots_radix,
323 (unsigned long)root->root_key.objectid,
324 BTRFS_ROOT_TRANS_TAG);
325 spin_unlock(&fs_info->fs_roots_radix_lock);
326 root->last_trans = trans->transid;
328 /* this is pretty tricky. We don't want to
329 * take the relocation lock in btrfs_record_root_in_trans
330 * unless we're really doing the first setup for this root in
333 * Normally we'd use root->last_trans as a flag to decide
334 * if we want to take the expensive mutex.
336 * But, we have to set root->last_trans before we
337 * init the relocation root, otherwise, we trip over warnings
338 * in ctree.c. The solution used here is to flag ourselves
339 * with root IN_TRANS_SETUP. When this is 1, we're still
340 * fixing up the reloc trees and everyone must wait.
342 * When this is zero, they can trust root->last_trans and fly
343 * through btrfs_record_root_in_trans without having to take the
344 * lock. smp_wmb() makes sure that all the writes above are
345 * done before we pop in the zero below
347 btrfs_init_reloc_root(trans, root);
348 smp_mb__before_atomic();
349 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
355 void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
356 struct btrfs_root *root)
358 struct btrfs_fs_info *fs_info = root->fs_info;
359 struct btrfs_transaction *cur_trans = trans->transaction;
361 /* Add ourselves to the transaction dropped list */
362 spin_lock(&cur_trans->dropped_roots_lock);
363 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
364 spin_unlock(&cur_trans->dropped_roots_lock);
366 /* Make sure we don't try to update the root at commit time */
367 spin_lock(&fs_info->fs_roots_radix_lock);
368 radix_tree_tag_clear(&fs_info->fs_roots_radix,
369 (unsigned long)root->root_key.objectid,
370 BTRFS_ROOT_TRANS_TAG);
371 spin_unlock(&fs_info->fs_roots_radix_lock);
374 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
375 struct btrfs_root *root)
377 struct btrfs_fs_info *fs_info = root->fs_info;
379 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
383 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
387 if (root->last_trans == trans->transid &&
388 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
391 mutex_lock(&fs_info->reloc_mutex);
392 record_root_in_trans(trans, root, 0);
393 mutex_unlock(&fs_info->reloc_mutex);
398 static inline int is_transaction_blocked(struct btrfs_transaction *trans)
400 return (trans->state >= TRANS_STATE_BLOCKED &&
401 trans->state < TRANS_STATE_UNBLOCKED &&
405 /* wait for commit against the current transaction to become unblocked
406 * when this is done, it is safe to start a new transaction, but the current
407 * transaction might not be fully on disk.
409 static void wait_current_trans(struct btrfs_fs_info *fs_info)
411 struct btrfs_transaction *cur_trans;
413 spin_lock(&fs_info->trans_lock);
414 cur_trans = fs_info->running_transaction;
415 if (cur_trans && is_transaction_blocked(cur_trans)) {
416 refcount_inc(&cur_trans->use_count);
417 spin_unlock(&fs_info->trans_lock);
419 wait_event(fs_info->transaction_wait,
420 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
422 btrfs_put_transaction(cur_trans);
424 spin_unlock(&fs_info->trans_lock);
428 static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
430 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
433 if (type == TRANS_START)
439 static inline bool need_reserve_reloc_root(struct btrfs_root *root)
441 struct btrfs_fs_info *fs_info = root->fs_info;
443 if (!fs_info->reloc_ctl ||
444 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
445 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
452 static struct btrfs_trans_handle *
453 start_transaction(struct btrfs_root *root, unsigned int num_items,
454 unsigned int type, enum btrfs_reserve_flush_enum flush,
455 bool enforce_qgroups)
457 struct btrfs_fs_info *fs_info = root->fs_info;
459 struct btrfs_trans_handle *h;
460 struct btrfs_transaction *cur_trans;
462 u64 qgroup_reserved = 0;
463 bool reloc_reserved = false;
466 /* Send isn't supposed to start transactions. */
467 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
469 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
470 return ERR_PTR(-EROFS);
472 if (current->journal_info) {
473 WARN_ON(type & TRANS_EXTWRITERS);
474 h = current->journal_info;
475 refcount_inc(&h->use_count);
476 WARN_ON(refcount_read(&h->use_count) > 2);
477 h->orig_rsv = h->block_rsv;
483 * Do the reservation before we join the transaction so we can do all
484 * the appropriate flushing if need be.
486 if (num_items && root != fs_info->chunk_root) {
487 qgroup_reserved = num_items * fs_info->nodesize;
488 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
493 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
495 * Do the reservation for the relocation root creation
497 if (need_reserve_reloc_root(root)) {
498 num_bytes += fs_info->nodesize;
499 reloc_reserved = true;
502 ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
508 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
515 * If we are JOIN_NOLOCK we're already committing a transaction and
516 * waiting on this guy, so we don't need to do the sb_start_intwrite
517 * because we're already holding a ref. We need this because we could
518 * have raced in and did an fsync() on a file which can kick a commit
519 * and then we deadlock with somebody doing a freeze.
521 * If we are ATTACH, it means we just want to catch the current
522 * transaction and commit it, so we needn't do sb_start_intwrite().
524 if (type & __TRANS_FREEZABLE)
525 sb_start_intwrite(fs_info->sb);
527 if (may_wait_transaction(fs_info, type))
528 wait_current_trans(fs_info);
531 ret = join_transaction(fs_info, type);
533 wait_current_trans(fs_info);
534 if (unlikely(type == TRANS_ATTACH))
537 } while (ret == -EBUSY);
542 cur_trans = fs_info->running_transaction;
544 h->transid = cur_trans->transid;
545 h->transaction = cur_trans;
547 refcount_set(&h->use_count, 1);
548 h->fs_info = root->fs_info;
551 h->can_flush_pending_bgs = true;
552 INIT_LIST_HEAD(&h->new_bgs);
555 if (cur_trans->state >= TRANS_STATE_BLOCKED &&
556 may_wait_transaction(fs_info, type)) {
557 current->journal_info = h;
558 btrfs_commit_transaction(h);
563 trace_btrfs_space_reservation(fs_info, "transaction",
564 h->transid, num_bytes, 1);
565 h->block_rsv = &fs_info->trans_block_rsv;
566 h->bytes_reserved = num_bytes;
567 h->reloc_reserved = reloc_reserved;
571 btrfs_record_root_in_trans(h, root);
573 if (!current->journal_info)
574 current->journal_info = h;
578 if (type & __TRANS_FREEZABLE)
579 sb_end_intwrite(fs_info->sb);
580 kmem_cache_free(btrfs_trans_handle_cachep, h);
583 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
586 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
590 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
591 unsigned int num_items)
593 return start_transaction(root, num_items, TRANS_START,
594 BTRFS_RESERVE_FLUSH_ALL, true);
597 struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
598 struct btrfs_root *root,
599 unsigned int num_items,
602 struct btrfs_fs_info *fs_info = root->fs_info;
603 struct btrfs_trans_handle *trans;
608 * We have two callers: unlink and block group removal. The
609 * former should succeed even if we will temporarily exceed
610 * quota and the latter operates on the extent root so
611 * qgroup enforcement is ignored anyway.
613 trans = start_transaction(root, num_items, TRANS_START,
614 BTRFS_RESERVE_FLUSH_ALL, false);
615 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
618 trans = btrfs_start_transaction(root, 0);
622 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
623 ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv,
624 num_bytes, min_factor);
626 btrfs_end_transaction(trans);
630 trans->block_rsv = &fs_info->trans_block_rsv;
631 trans->bytes_reserved = num_bytes;
632 trace_btrfs_space_reservation(fs_info, "transaction",
633 trans->transid, num_bytes, 1);
638 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
640 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
644 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
646 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
647 BTRFS_RESERVE_NO_FLUSH, true);
651 * btrfs_attach_transaction() - catch the running transaction
653 * It is used when we want to commit the current the transaction, but
654 * don't want to start a new one.
656 * Note: If this function return -ENOENT, it just means there is no
657 * running transaction. But it is possible that the inactive transaction
658 * is still in the memory, not fully on disk. If you hope there is no
659 * inactive transaction in the fs when -ENOENT is returned, you should
661 * btrfs_attach_transaction_barrier()
663 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
665 return start_transaction(root, 0, TRANS_ATTACH,
666 BTRFS_RESERVE_NO_FLUSH, true);
670 * btrfs_attach_transaction_barrier() - catch the running transaction
672 * It is similar to the above function, the differentia is this one
673 * will wait for all the inactive transactions until they fully
676 struct btrfs_trans_handle *
677 btrfs_attach_transaction_barrier(struct btrfs_root *root)
679 struct btrfs_trans_handle *trans;
681 trans = start_transaction(root, 0, TRANS_ATTACH,
682 BTRFS_RESERVE_NO_FLUSH, true);
683 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
684 btrfs_wait_for_commit(root->fs_info, 0);
689 /* wait for a transaction commit to be fully complete */
690 static noinline void wait_for_commit(struct btrfs_transaction *commit)
692 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
695 int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
697 struct btrfs_transaction *cur_trans = NULL, *t;
701 if (transid <= fs_info->last_trans_committed)
704 /* find specified transaction */
705 spin_lock(&fs_info->trans_lock);
706 list_for_each_entry(t, &fs_info->trans_list, list) {
707 if (t->transid == transid) {
709 refcount_inc(&cur_trans->use_count);
713 if (t->transid > transid) {
718 spin_unlock(&fs_info->trans_lock);
721 * The specified transaction doesn't exist, or we
722 * raced with btrfs_commit_transaction
725 if (transid > fs_info->last_trans_committed)
730 /* find newest transaction that is committing | committed */
731 spin_lock(&fs_info->trans_lock);
732 list_for_each_entry_reverse(t, &fs_info->trans_list,
734 if (t->state >= TRANS_STATE_COMMIT_START) {
735 if (t->state == TRANS_STATE_COMPLETED)
738 refcount_inc(&cur_trans->use_count);
742 spin_unlock(&fs_info->trans_lock);
744 goto out; /* nothing committing|committed */
747 wait_for_commit(cur_trans);
748 btrfs_put_transaction(cur_trans);
753 void btrfs_throttle(struct btrfs_fs_info *fs_info)
755 wait_current_trans(fs_info);
758 static int should_end_transaction(struct btrfs_trans_handle *trans)
760 struct btrfs_fs_info *fs_info = trans->fs_info;
762 if (btrfs_check_space_for_delayed_refs(trans, fs_info))
765 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
768 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
770 struct btrfs_transaction *cur_trans = trans->transaction;
775 if (cur_trans->state >= TRANS_STATE_BLOCKED ||
776 cur_trans->delayed_refs.flushing)
779 updates = trans->delayed_ref_updates;
780 trans->delayed_ref_updates = 0;
782 err = btrfs_run_delayed_refs(trans, updates * 2);
783 if (err) /* Error code will also eval true */
787 return should_end_transaction(trans);
790 static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
793 struct btrfs_fs_info *fs_info = trans->fs_info;
795 if (!trans->block_rsv) {
796 ASSERT(!trans->bytes_reserved);
800 if (!trans->bytes_reserved)
803 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
804 trace_btrfs_space_reservation(fs_info, "transaction",
805 trans->transid, trans->bytes_reserved, 0);
806 btrfs_block_rsv_release(fs_info, trans->block_rsv,
807 trans->bytes_reserved);
808 trans->bytes_reserved = 0;
811 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
814 struct btrfs_fs_info *info = trans->fs_info;
815 struct btrfs_transaction *cur_trans = trans->transaction;
816 u64 transid = trans->transid;
817 unsigned long cur = trans->delayed_ref_updates;
818 int lock = (trans->type != TRANS_JOIN_NOLOCK);
820 int must_run_delayed_refs = 0;
822 if (refcount_read(&trans->use_count) > 1) {
823 refcount_dec(&trans->use_count);
824 trans->block_rsv = trans->orig_rsv;
828 btrfs_trans_release_metadata(trans);
829 trans->block_rsv = NULL;
831 if (!list_empty(&trans->new_bgs))
832 btrfs_create_pending_block_groups(trans);
834 trans->delayed_ref_updates = 0;
836 must_run_delayed_refs =
837 btrfs_should_throttle_delayed_refs(trans, info);
838 cur = max_t(unsigned long, cur, 32);
841 * don't make the caller wait if they are from a NOLOCK
842 * or ATTACH transaction, it will deadlock with commit
844 if (must_run_delayed_refs == 1 &&
845 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH)))
846 must_run_delayed_refs = 2;
849 btrfs_trans_release_metadata(trans);
850 trans->block_rsv = NULL;
852 if (!list_empty(&trans->new_bgs))
853 btrfs_create_pending_block_groups(trans);
855 btrfs_trans_release_chunk_metadata(trans);
857 if (lock && should_end_transaction(trans) &&
858 READ_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
859 spin_lock(&info->trans_lock);
860 if (cur_trans->state == TRANS_STATE_RUNNING)
861 cur_trans->state = TRANS_STATE_BLOCKED;
862 spin_unlock(&info->trans_lock);
865 if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
867 return btrfs_commit_transaction(trans);
869 wake_up_process(info->transaction_kthread);
872 if (trans->type & __TRANS_FREEZABLE)
873 sb_end_intwrite(info->sb);
875 WARN_ON(cur_trans != info->running_transaction);
876 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
877 atomic_dec(&cur_trans->num_writers);
878 extwriter_counter_dec(cur_trans, trans->type);
880 cond_wake_up(&cur_trans->writer_wait);
881 btrfs_put_transaction(cur_trans);
883 if (current->journal_info == trans)
884 current->journal_info = NULL;
887 btrfs_run_delayed_iputs(info);
889 if (trans->aborted ||
890 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
891 wake_up_process(info->transaction_kthread);
895 kmem_cache_free(btrfs_trans_handle_cachep, trans);
896 if (must_run_delayed_refs) {
897 btrfs_async_run_delayed_refs(info, cur, transid,
898 must_run_delayed_refs == 1);
903 int btrfs_end_transaction(struct btrfs_trans_handle *trans)
905 return __btrfs_end_transaction(trans, 0);
908 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
910 return __btrfs_end_transaction(trans, 1);
914 * when btree blocks are allocated, they have some corresponding bits set for
915 * them in one of two extent_io trees. This is used to make sure all of
916 * those extents are sent to disk but does not wait on them
918 int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
919 struct extent_io_tree *dirty_pages, int mark)
923 struct address_space *mapping = fs_info->btree_inode->i_mapping;
924 struct extent_state *cached_state = NULL;
928 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
929 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
930 mark, &cached_state)) {
931 bool wait_writeback = false;
933 err = convert_extent_bit(dirty_pages, start, end,
935 mark, &cached_state);
937 * convert_extent_bit can return -ENOMEM, which is most of the
938 * time a temporary error. So when it happens, ignore the error
939 * and wait for writeback of this range to finish - because we
940 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
941 * to __btrfs_wait_marked_extents() would not know that
942 * writeback for this range started and therefore wouldn't
943 * wait for it to finish - we don't want to commit a
944 * superblock that points to btree nodes/leafs for which
945 * writeback hasn't finished yet (and without errors).
946 * We cleanup any entries left in the io tree when committing
947 * the transaction (through clear_btree_io_tree()).
949 if (err == -ENOMEM) {
951 wait_writeback = true;
954 err = filemap_fdatawrite_range(mapping, start, end);
957 else if (wait_writeback)
958 werr = filemap_fdatawait_range(mapping, start, end);
959 free_extent_state(cached_state);
964 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
969 * when btree blocks are allocated, they have some corresponding bits set for
970 * them in one of two extent_io trees. This is used to make sure all of
971 * those extents are on disk for transaction or log commit. We wait
972 * on all the pages and clear them from the dirty pages state tree
974 static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
975 struct extent_io_tree *dirty_pages)
979 struct address_space *mapping = fs_info->btree_inode->i_mapping;
980 struct extent_state *cached_state = NULL;
984 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
985 EXTENT_NEED_WAIT, &cached_state)) {
987 * Ignore -ENOMEM errors returned by clear_extent_bit().
988 * When committing the transaction, we'll remove any entries
989 * left in the io tree. For a log commit, we don't remove them
990 * after committing the log because the tree can be accessed
991 * concurrently - we do it only at transaction commit time when
992 * it's safe to do it (through clear_btree_io_tree()).
994 err = clear_extent_bit(dirty_pages, start, end,
995 EXTENT_NEED_WAIT, 0, 0, &cached_state);
999 err = filemap_fdatawait_range(mapping, start, end);
1002 free_extent_state(cached_state);
1003 cached_state = NULL;
1012 int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1013 struct extent_io_tree *dirty_pages)
1015 bool errors = false;
1018 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1019 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1027 int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1029 struct btrfs_fs_info *fs_info = log_root->fs_info;
1030 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1031 bool errors = false;
1034 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1036 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1037 if ((mark & EXTENT_DIRTY) &&
1038 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1041 if ((mark & EXTENT_NEW) &&
1042 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1051 * When btree blocks are allocated the corresponding extents are marked dirty.
1052 * This function ensures such extents are persisted on disk for transaction or
1055 * @trans: transaction whose dirty pages we'd like to write
1057 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1061 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1062 struct btrfs_fs_info *fs_info = trans->fs_info;
1063 struct blk_plug plug;
1065 blk_start_plug(&plug);
1066 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1067 blk_finish_plug(&plug);
1068 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1070 clear_btree_io_tree(&trans->transaction->dirty_pages);
1081 * this is used to update the root pointer in the tree of tree roots.
1083 * But, in the case of the extent allocation tree, updating the root
1084 * pointer may allocate blocks which may change the root of the extent
1087 * So, this loops and repeats and makes sure the cowonly root didn't
1088 * change while the root pointer was being updated in the metadata.
1090 static int update_cowonly_root(struct btrfs_trans_handle *trans,
1091 struct btrfs_root *root)
1094 u64 old_root_bytenr;
1096 struct btrfs_fs_info *fs_info = root->fs_info;
1097 struct btrfs_root *tree_root = fs_info->tree_root;
1099 old_root_used = btrfs_root_used(&root->root_item);
1102 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1103 if (old_root_bytenr == root->node->start &&
1104 old_root_used == btrfs_root_used(&root->root_item))
1107 btrfs_set_root_node(&root->root_item, root->node);
1108 ret = btrfs_update_root(trans, tree_root,
1114 old_root_used = btrfs_root_used(&root->root_item);
1121 * update all the cowonly tree roots on disk
1123 * The error handling in this function may not be obvious. Any of the
1124 * failures will cause the file system to go offline. We still need
1125 * to clean up the delayed refs.
1127 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1129 struct btrfs_fs_info *fs_info = trans->fs_info;
1130 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1131 struct list_head *io_bgs = &trans->transaction->io_bgs;
1132 struct list_head *next;
1133 struct extent_buffer *eb;
1136 eb = btrfs_lock_root_node(fs_info->tree_root);
1137 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1139 btrfs_tree_unlock(eb);
1140 free_extent_buffer(eb);
1145 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1149 ret = btrfs_run_dev_stats(trans, fs_info);
1152 ret = btrfs_run_dev_replace(trans, fs_info);
1155 ret = btrfs_run_qgroups(trans, fs_info);
1159 ret = btrfs_setup_space_cache(trans, fs_info);
1163 /* run_qgroups might have added some more refs */
1164 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1168 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1169 struct btrfs_root *root;
1170 next = fs_info->dirty_cowonly_roots.next;
1171 list_del_init(next);
1172 root = list_entry(next, struct btrfs_root, dirty_list);
1173 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1175 if (root != fs_info->extent_root)
1176 list_add_tail(&root->dirty_list,
1177 &trans->transaction->switch_commits);
1178 ret = update_cowonly_root(trans, root);
1181 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1186 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1187 ret = btrfs_write_dirty_block_groups(trans, fs_info);
1190 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1195 if (!list_empty(&fs_info->dirty_cowonly_roots))
1198 list_add_tail(&fs_info->extent_root->dirty_list,
1199 &trans->transaction->switch_commits);
1200 btrfs_after_dev_replace_commit(fs_info);
1206 * dead roots are old snapshots that need to be deleted. This allocates
1207 * a dirty root struct and adds it into the list of dead roots that need to
1210 void btrfs_add_dead_root(struct btrfs_root *root)
1212 struct btrfs_fs_info *fs_info = root->fs_info;
1214 spin_lock(&fs_info->trans_lock);
1215 if (list_empty(&root->root_list))
1216 list_add_tail(&root->root_list, &fs_info->dead_roots);
1217 spin_unlock(&fs_info->trans_lock);
1221 * update all the cowonly tree roots on disk
1223 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1225 struct btrfs_fs_info *fs_info = trans->fs_info;
1226 struct btrfs_root *gang[8];
1231 spin_lock(&fs_info->fs_roots_radix_lock);
1233 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1236 BTRFS_ROOT_TRANS_TAG);
1239 for (i = 0; i < ret; i++) {
1240 struct btrfs_root *root = gang[i];
1241 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1242 (unsigned long)root->root_key.objectid,
1243 BTRFS_ROOT_TRANS_TAG);
1244 spin_unlock(&fs_info->fs_roots_radix_lock);
1246 btrfs_free_log(trans, root);
1247 btrfs_update_reloc_root(trans, root);
1249 btrfs_save_ino_cache(root, trans);
1251 /* see comments in should_cow_block() */
1252 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1253 smp_mb__after_atomic();
1255 if (root->commit_root != root->node) {
1256 list_add_tail(&root->dirty_list,
1257 &trans->transaction->switch_commits);
1258 btrfs_set_root_node(&root->root_item,
1262 err = btrfs_update_root(trans, fs_info->tree_root,
1265 spin_lock(&fs_info->fs_roots_radix_lock);
1268 btrfs_qgroup_free_meta_all_pertrans(root);
1271 spin_unlock(&fs_info->fs_roots_radix_lock);
1276 * defrag a given btree.
1277 * Every leaf in the btree is read and defragged.
1279 int btrfs_defrag_root(struct btrfs_root *root)
1281 struct btrfs_fs_info *info = root->fs_info;
1282 struct btrfs_trans_handle *trans;
1285 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1289 trans = btrfs_start_transaction(root, 0);
1291 return PTR_ERR(trans);
1293 ret = btrfs_defrag_leaves(trans, root);
1295 btrfs_end_transaction(trans);
1296 btrfs_btree_balance_dirty(info);
1299 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1302 if (btrfs_defrag_cancelled(info)) {
1303 btrfs_debug(info, "defrag_root cancelled");
1308 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1313 * Do all special snapshot related qgroup dirty hack.
1315 * Will do all needed qgroup inherit and dirty hack like switch commit
1316 * roots inside one transaction and write all btree into disk, to make
1319 static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1320 struct btrfs_root *src,
1321 struct btrfs_root *parent,
1322 struct btrfs_qgroup_inherit *inherit,
1325 struct btrfs_fs_info *fs_info = src->fs_info;
1329 * Save some performance in the case that qgroups are not
1330 * enabled. If this check races with the ioctl, rescan will
1333 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1337 * Ensure dirty @src will be commited. Or, after comming
1338 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1339 * recorded root will never be updated again, causing an outdated root
1342 record_root_in_trans(trans, src, 1);
1345 * We are going to commit transaction, see btrfs_commit_transaction()
1346 * comment for reason locking tree_log_mutex
1348 mutex_lock(&fs_info->tree_log_mutex);
1350 ret = commit_fs_roots(trans);
1353 ret = btrfs_qgroup_account_extents(trans);
1357 /* Now qgroup are all updated, we can inherit it to new qgroups */
1358 ret = btrfs_qgroup_inherit(trans, fs_info,
1359 src->root_key.objectid, dst_objectid,
1365 * Now we do a simplified commit transaction, which will:
1366 * 1) commit all subvolume and extent tree
1367 * To ensure all subvolume and extent tree have a valid
1368 * commit_root to accounting later insert_dir_item()
1369 * 2) write all btree blocks onto disk
1370 * This is to make sure later btree modification will be cowed
1371 * Or commit_root can be populated and cause wrong qgroup numbers
1372 * In this simplified commit, we don't really care about other trees
1373 * like chunk and root tree, as they won't affect qgroup.
1374 * And we don't write super to avoid half committed status.
1376 ret = commit_cowonly_roots(trans);
1379 switch_commit_roots(trans->transaction);
1380 ret = btrfs_write_and_wait_transaction(trans);
1382 btrfs_handle_fs_error(fs_info, ret,
1383 "Error while writing out transaction for qgroup");
1386 mutex_unlock(&fs_info->tree_log_mutex);
1389 * Force parent root to be updated, as we recorded it before so its
1390 * last_trans == cur_transid.
1391 * Or it won't be committed again onto disk after later
1395 record_root_in_trans(trans, parent, 1);
1400 * new snapshots need to be created at a very specific time in the
1401 * transaction commit. This does the actual creation.
1404 * If the error which may affect the commitment of the current transaction
1405 * happens, we should return the error number. If the error which just affect
1406 * the creation of the pending snapshots, just return 0.
1408 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1409 struct btrfs_pending_snapshot *pending)
1412 struct btrfs_fs_info *fs_info = trans->fs_info;
1413 struct btrfs_key key;
1414 struct btrfs_root_item *new_root_item;
1415 struct btrfs_root *tree_root = fs_info->tree_root;
1416 struct btrfs_root *root = pending->root;
1417 struct btrfs_root *parent_root;
1418 struct btrfs_block_rsv *rsv;
1419 struct inode *parent_inode;
1420 struct btrfs_path *path;
1421 struct btrfs_dir_item *dir_item;
1422 struct dentry *dentry;
1423 struct extent_buffer *tmp;
1424 struct extent_buffer *old;
1425 struct timespec64 cur_time;
1433 ASSERT(pending->path);
1434 path = pending->path;
1436 ASSERT(pending->root_item);
1437 new_root_item = pending->root_item;
1439 pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1441 goto no_free_objectid;
1444 * Make qgroup to skip current new snapshot's qgroupid, as it is
1445 * accounted by later btrfs_qgroup_inherit().
1447 btrfs_set_skip_qgroup(trans, objectid);
1449 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1451 if (to_reserve > 0) {
1452 pending->error = btrfs_block_rsv_add(root,
1453 &pending->block_rsv,
1455 BTRFS_RESERVE_NO_FLUSH);
1457 goto clear_skip_qgroup;
1460 key.objectid = objectid;
1461 key.offset = (u64)-1;
1462 key.type = BTRFS_ROOT_ITEM_KEY;
1464 rsv = trans->block_rsv;
1465 trans->block_rsv = &pending->block_rsv;
1466 trans->bytes_reserved = trans->block_rsv->reserved;
1467 trace_btrfs_space_reservation(fs_info, "transaction",
1469 trans->bytes_reserved, 1);
1470 dentry = pending->dentry;
1471 parent_inode = pending->dir;
1472 parent_root = BTRFS_I(parent_inode)->root;
1473 record_root_in_trans(trans, parent_root, 0);
1475 cur_time = current_time(parent_inode);
1478 * insert the directory item
1480 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1481 BUG_ON(ret); /* -ENOMEM */
1483 /* check if there is a file/dir which has the same name. */
1484 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1485 btrfs_ino(BTRFS_I(parent_inode)),
1486 dentry->d_name.name,
1487 dentry->d_name.len, 0);
1488 if (dir_item != NULL && !IS_ERR(dir_item)) {
1489 pending->error = -EEXIST;
1490 goto dir_item_existed;
1491 } else if (IS_ERR(dir_item)) {
1492 ret = PTR_ERR(dir_item);
1493 btrfs_abort_transaction(trans, ret);
1496 btrfs_release_path(path);
1499 * pull in the delayed directory update
1500 * and the delayed inode item
1501 * otherwise we corrupt the FS during
1504 ret = btrfs_run_delayed_items(trans);
1505 if (ret) { /* Transaction aborted */
1506 btrfs_abort_transaction(trans, ret);
1510 record_root_in_trans(trans, root, 0);
1511 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1512 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1513 btrfs_check_and_init_root_item(new_root_item);
1515 root_flags = btrfs_root_flags(new_root_item);
1516 if (pending->readonly)
1517 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1519 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1520 btrfs_set_root_flags(new_root_item, root_flags);
1522 btrfs_set_root_generation_v2(new_root_item,
1524 uuid_le_gen(&new_uuid);
1525 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1526 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1528 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1529 memset(new_root_item->received_uuid, 0,
1530 sizeof(new_root_item->received_uuid));
1531 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1532 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1533 btrfs_set_root_stransid(new_root_item, 0);
1534 btrfs_set_root_rtransid(new_root_item, 0);
1536 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1537 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1538 btrfs_set_root_otransid(new_root_item, trans->transid);
1540 old = btrfs_lock_root_node(root);
1541 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1543 btrfs_tree_unlock(old);
1544 free_extent_buffer(old);
1545 btrfs_abort_transaction(trans, ret);
1549 btrfs_set_lock_blocking(old);
1551 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1552 /* clean up in any case */
1553 btrfs_tree_unlock(old);
1554 free_extent_buffer(old);
1556 btrfs_abort_transaction(trans, ret);
1559 /* see comments in should_cow_block() */
1560 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1563 btrfs_set_root_node(new_root_item, tmp);
1564 /* record when the snapshot was created in key.offset */
1565 key.offset = trans->transid;
1566 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1567 btrfs_tree_unlock(tmp);
1568 free_extent_buffer(tmp);
1570 btrfs_abort_transaction(trans, ret);
1575 * insert root back/forward references
1577 ret = btrfs_add_root_ref(trans, fs_info, objectid,
1578 parent_root->root_key.objectid,
1579 btrfs_ino(BTRFS_I(parent_inode)), index,
1580 dentry->d_name.name, dentry->d_name.len);
1582 btrfs_abort_transaction(trans, ret);
1586 key.offset = (u64)-1;
1587 pending->snap = btrfs_read_fs_root_no_name(fs_info, &key);
1588 if (IS_ERR(pending->snap)) {
1589 ret = PTR_ERR(pending->snap);
1590 btrfs_abort_transaction(trans, ret);
1594 ret = btrfs_reloc_post_snapshot(trans, pending);
1596 btrfs_abort_transaction(trans, ret);
1600 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1602 btrfs_abort_transaction(trans, ret);
1607 * Do special qgroup accounting for snapshot, as we do some qgroup
1608 * snapshot hack to do fast snapshot.
1609 * To co-operate with that hack, we do hack again.
1610 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1612 ret = qgroup_account_snapshot(trans, root, parent_root,
1613 pending->inherit, objectid);
1617 ret = btrfs_insert_dir_item(trans, parent_root,
1618 dentry->d_name.name, dentry->d_name.len,
1619 BTRFS_I(parent_inode), &key,
1620 BTRFS_FT_DIR, index);
1621 /* We have check then name at the beginning, so it is impossible. */
1622 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1624 btrfs_abort_transaction(trans, ret);
1628 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1629 dentry->d_name.len * 2);
1630 parent_inode->i_mtime = parent_inode->i_ctime =
1631 current_time(parent_inode);
1632 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1634 btrfs_abort_transaction(trans, ret);
1637 ret = btrfs_uuid_tree_add(trans, new_uuid.b, BTRFS_UUID_KEY_SUBVOL,
1640 btrfs_abort_transaction(trans, ret);
1643 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1644 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1645 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1647 if (ret && ret != -EEXIST) {
1648 btrfs_abort_transaction(trans, ret);
1653 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1655 btrfs_abort_transaction(trans, ret);
1660 pending->error = ret;
1662 trans->block_rsv = rsv;
1663 trans->bytes_reserved = 0;
1665 btrfs_clear_skip_qgroup(trans);
1667 kfree(new_root_item);
1668 pending->root_item = NULL;
1669 btrfs_free_path(path);
1670 pending->path = NULL;
1676 * create all the snapshots we've scheduled for creation
1678 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1680 struct btrfs_pending_snapshot *pending, *next;
1681 struct list_head *head = &trans->transaction->pending_snapshots;
1684 list_for_each_entry_safe(pending, next, head, list) {
1685 list_del(&pending->list);
1686 ret = create_pending_snapshot(trans, pending);
1693 static void update_super_roots(struct btrfs_fs_info *fs_info)
1695 struct btrfs_root_item *root_item;
1696 struct btrfs_super_block *super;
1698 super = fs_info->super_copy;
1700 root_item = &fs_info->chunk_root->root_item;
1701 super->chunk_root = root_item->bytenr;
1702 super->chunk_root_generation = root_item->generation;
1703 super->chunk_root_level = root_item->level;
1705 root_item = &fs_info->tree_root->root_item;
1706 super->root = root_item->bytenr;
1707 super->generation = root_item->generation;
1708 super->root_level = root_item->level;
1709 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1710 super->cache_generation = root_item->generation;
1711 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1712 super->uuid_tree_generation = root_item->generation;
1715 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1717 struct btrfs_transaction *trans;
1720 spin_lock(&info->trans_lock);
1721 trans = info->running_transaction;
1723 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1724 spin_unlock(&info->trans_lock);
1728 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1730 struct btrfs_transaction *trans;
1733 spin_lock(&info->trans_lock);
1734 trans = info->running_transaction;
1736 ret = is_transaction_blocked(trans);
1737 spin_unlock(&info->trans_lock);
1742 * wait for the current transaction commit to start and block subsequent
1745 static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info,
1746 struct btrfs_transaction *trans)
1748 wait_event(fs_info->transaction_blocked_wait,
1749 trans->state >= TRANS_STATE_COMMIT_START || trans->aborted);
1753 * wait for the current transaction to start and then become unblocked.
1756 static void wait_current_trans_commit_start_and_unblock(
1757 struct btrfs_fs_info *fs_info,
1758 struct btrfs_transaction *trans)
1760 wait_event(fs_info->transaction_wait,
1761 trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted);
1765 * commit transactions asynchronously. once btrfs_commit_transaction_async
1766 * returns, any subsequent transaction will not be allowed to join.
1768 struct btrfs_async_commit {
1769 struct btrfs_trans_handle *newtrans;
1770 struct work_struct work;
1773 static void do_async_commit(struct work_struct *work)
1775 struct btrfs_async_commit *ac =
1776 container_of(work, struct btrfs_async_commit, work);
1779 * We've got freeze protection passed with the transaction.
1780 * Tell lockdep about it.
1782 if (ac->newtrans->type & __TRANS_FREEZABLE)
1783 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
1785 current->journal_info = ac->newtrans;
1787 btrfs_commit_transaction(ac->newtrans);
1791 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1792 int wait_for_unblock)
1794 struct btrfs_fs_info *fs_info = trans->fs_info;
1795 struct btrfs_async_commit *ac;
1796 struct btrfs_transaction *cur_trans;
1798 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1802 INIT_WORK(&ac->work, do_async_commit);
1803 ac->newtrans = btrfs_join_transaction(trans->root);
1804 if (IS_ERR(ac->newtrans)) {
1805 int err = PTR_ERR(ac->newtrans);
1810 /* take transaction reference */
1811 cur_trans = trans->transaction;
1812 refcount_inc(&cur_trans->use_count);
1814 btrfs_end_transaction(trans);
1817 * Tell lockdep we've released the freeze rwsem, since the
1818 * async commit thread will be the one to unlock it.
1820 if (ac->newtrans->type & __TRANS_FREEZABLE)
1821 __sb_writers_release(fs_info->sb, SB_FREEZE_FS);
1823 schedule_work(&ac->work);
1825 /* wait for transaction to start and unblock */
1826 if (wait_for_unblock)
1827 wait_current_trans_commit_start_and_unblock(fs_info, cur_trans);
1829 wait_current_trans_commit_start(fs_info, cur_trans);
1831 if (current->journal_info == trans)
1832 current->journal_info = NULL;
1834 btrfs_put_transaction(cur_trans);
1839 static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1841 struct btrfs_fs_info *fs_info = trans->fs_info;
1842 struct btrfs_transaction *cur_trans = trans->transaction;
1845 WARN_ON(refcount_read(&trans->use_count) > 1);
1847 btrfs_abort_transaction(trans, err);
1849 spin_lock(&fs_info->trans_lock);
1852 * If the transaction is removed from the list, it means this
1853 * transaction has been committed successfully, so it is impossible
1854 * to call the cleanup function.
1856 BUG_ON(list_empty(&cur_trans->list));
1858 list_del_init(&cur_trans->list);
1859 if (cur_trans == fs_info->running_transaction) {
1860 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1861 spin_unlock(&fs_info->trans_lock);
1862 wait_event(cur_trans->writer_wait,
1863 atomic_read(&cur_trans->num_writers) == 1);
1865 spin_lock(&fs_info->trans_lock);
1867 spin_unlock(&fs_info->trans_lock);
1869 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
1871 spin_lock(&fs_info->trans_lock);
1872 if (cur_trans == fs_info->running_transaction)
1873 fs_info->running_transaction = NULL;
1874 spin_unlock(&fs_info->trans_lock);
1876 if (trans->type & __TRANS_FREEZABLE)
1877 sb_end_intwrite(fs_info->sb);
1878 btrfs_put_transaction(cur_trans);
1879 btrfs_put_transaction(cur_trans);
1881 trace_btrfs_transaction_commit(trans->root);
1883 if (current->journal_info == trans)
1884 current->journal_info = NULL;
1885 btrfs_scrub_cancel(fs_info);
1887 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1890 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1893 * We use writeback_inodes_sb here because if we used
1894 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
1895 * Currently are holding the fs freeze lock, if we do an async flush
1896 * we'll do btrfs_join_transaction() and deadlock because we need to
1897 * wait for the fs freeze lock. Using the direct flushing we benefit
1898 * from already being in a transaction and our join_transaction doesn't
1899 * have to re-take the fs freeze lock.
1901 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1902 writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
1906 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1908 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1909 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1913 btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans)
1915 wait_event(cur_trans->pending_wait,
1916 atomic_read(&cur_trans->pending_ordered) == 0);
1919 int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
1921 struct btrfs_fs_info *fs_info = trans->fs_info;
1922 struct btrfs_transaction *cur_trans = trans->transaction;
1923 struct btrfs_transaction *prev_trans = NULL;
1926 /* Stop the commit early if ->aborted is set */
1927 if (unlikely(READ_ONCE(cur_trans->aborted))) {
1928 ret = cur_trans->aborted;
1929 btrfs_end_transaction(trans);
1933 /* make a pass through all the delayed refs we have so far
1934 * any runnings procs may add more while we are here
1936 ret = btrfs_run_delayed_refs(trans, 0);
1938 btrfs_end_transaction(trans);
1942 btrfs_trans_release_metadata(trans);
1943 trans->block_rsv = NULL;
1945 cur_trans = trans->transaction;
1948 * set the flushing flag so procs in this transaction have to
1949 * start sending their work down.
1951 cur_trans->delayed_refs.flushing = 1;
1954 if (!list_empty(&trans->new_bgs))
1955 btrfs_create_pending_block_groups(trans);
1957 ret = btrfs_run_delayed_refs(trans, 0);
1959 btrfs_end_transaction(trans);
1963 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
1966 /* this mutex is also taken before trying to set
1967 * block groups readonly. We need to make sure
1968 * that nobody has set a block group readonly
1969 * after a extents from that block group have been
1970 * allocated for cache files. btrfs_set_block_group_ro
1971 * will wait for the transaction to commit if it
1972 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
1974 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
1975 * only one process starts all the block group IO. It wouldn't
1976 * hurt to have more than one go through, but there's no
1977 * real advantage to it either.
1979 mutex_lock(&fs_info->ro_block_group_mutex);
1980 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
1983 mutex_unlock(&fs_info->ro_block_group_mutex);
1986 ret = btrfs_start_dirty_block_groups(trans);
1988 btrfs_end_transaction(trans);
1994 spin_lock(&fs_info->trans_lock);
1995 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
1996 spin_unlock(&fs_info->trans_lock);
1997 refcount_inc(&cur_trans->use_count);
1998 ret = btrfs_end_transaction(trans);
2000 wait_for_commit(cur_trans);
2002 if (unlikely(cur_trans->aborted))
2003 ret = cur_trans->aborted;
2005 btrfs_put_transaction(cur_trans);
2010 cur_trans->state = TRANS_STATE_COMMIT_START;
2011 wake_up(&fs_info->transaction_blocked_wait);
2013 if (cur_trans->list.prev != &fs_info->trans_list) {
2014 prev_trans = list_entry(cur_trans->list.prev,
2015 struct btrfs_transaction, list);
2016 if (prev_trans->state != TRANS_STATE_COMPLETED) {
2017 refcount_inc(&prev_trans->use_count);
2018 spin_unlock(&fs_info->trans_lock);
2020 wait_for_commit(prev_trans);
2021 ret = prev_trans->aborted;
2023 btrfs_put_transaction(prev_trans);
2025 goto cleanup_transaction;
2027 spin_unlock(&fs_info->trans_lock);
2030 spin_unlock(&fs_info->trans_lock);
2033 extwriter_counter_dec(cur_trans, trans->type);
2035 ret = btrfs_start_delalloc_flush(fs_info);
2037 goto cleanup_transaction;
2039 ret = btrfs_run_delayed_items(trans);
2041 goto cleanup_transaction;
2043 wait_event(cur_trans->writer_wait,
2044 extwriter_counter_read(cur_trans) == 0);
2046 /* some pending stuffs might be added after the previous flush. */
2047 ret = btrfs_run_delayed_items(trans);
2049 goto cleanup_transaction;
2051 btrfs_wait_delalloc_flush(fs_info);
2053 btrfs_wait_pending_ordered(cur_trans);
2055 btrfs_scrub_pause(fs_info);
2057 * Ok now we need to make sure to block out any other joins while we
2058 * commit the transaction. We could have started a join before setting
2059 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2061 spin_lock(&fs_info->trans_lock);
2062 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2063 spin_unlock(&fs_info->trans_lock);
2064 wait_event(cur_trans->writer_wait,
2065 atomic_read(&cur_trans->num_writers) == 1);
2067 /* ->aborted might be set after the previous check, so check it */
2068 if (unlikely(READ_ONCE(cur_trans->aborted))) {
2069 ret = cur_trans->aborted;
2070 goto scrub_continue;
2073 * the reloc mutex makes sure that we stop
2074 * the balancing code from coming in and moving
2075 * extents around in the middle of the commit
2077 mutex_lock(&fs_info->reloc_mutex);
2080 * We needn't worry about the delayed items because we will
2081 * deal with them in create_pending_snapshot(), which is the
2082 * core function of the snapshot creation.
2084 ret = create_pending_snapshots(trans);
2086 mutex_unlock(&fs_info->reloc_mutex);
2087 goto scrub_continue;
2091 * We insert the dir indexes of the snapshots and update the inode
2092 * of the snapshots' parents after the snapshot creation, so there
2093 * are some delayed items which are not dealt with. Now deal with
2096 * We needn't worry that this operation will corrupt the snapshots,
2097 * because all the tree which are snapshoted will be forced to COW
2098 * the nodes and leaves.
2100 ret = btrfs_run_delayed_items(trans);
2102 mutex_unlock(&fs_info->reloc_mutex);
2103 goto scrub_continue;
2106 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2108 mutex_unlock(&fs_info->reloc_mutex);
2109 goto scrub_continue;
2113 * make sure none of the code above managed to slip in a
2116 btrfs_assert_delayed_root_empty(fs_info);
2118 WARN_ON(cur_trans != trans->transaction);
2120 /* btrfs_commit_tree_roots is responsible for getting the
2121 * various roots consistent with each other. Every pointer
2122 * in the tree of tree roots has to point to the most up to date
2123 * root for every subvolume and other tree. So, we have to keep
2124 * the tree logging code from jumping in and changing any
2127 * At this point in the commit, there can't be any tree-log
2128 * writers, but a little lower down we drop the trans mutex
2129 * and let new people in. By holding the tree_log_mutex
2130 * from now until after the super is written, we avoid races
2131 * with the tree-log code.
2133 mutex_lock(&fs_info->tree_log_mutex);
2135 ret = commit_fs_roots(trans);
2137 mutex_unlock(&fs_info->tree_log_mutex);
2138 mutex_unlock(&fs_info->reloc_mutex);
2139 goto scrub_continue;
2143 * Since the transaction is done, we can apply the pending changes
2144 * before the next transaction.
2146 btrfs_apply_pending_changes(fs_info);
2148 /* commit_fs_roots gets rid of all the tree log roots, it is now
2149 * safe to free the root of tree log roots
2151 btrfs_free_log_root_tree(trans, fs_info);
2154 * commit_fs_roots() can call btrfs_save_ino_cache(), which generates
2155 * new delayed refs. Must handle them or qgroup can be wrong.
2157 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2159 mutex_unlock(&fs_info->tree_log_mutex);
2160 mutex_unlock(&fs_info->reloc_mutex);
2161 goto scrub_continue;
2165 * Since fs roots are all committed, we can get a quite accurate
2166 * new_roots. So let's do quota accounting.
2168 ret = btrfs_qgroup_account_extents(trans);
2170 mutex_unlock(&fs_info->tree_log_mutex);
2171 mutex_unlock(&fs_info->reloc_mutex);
2172 goto scrub_continue;
2175 ret = commit_cowonly_roots(trans);
2177 mutex_unlock(&fs_info->tree_log_mutex);
2178 mutex_unlock(&fs_info->reloc_mutex);
2179 goto scrub_continue;
2183 * The tasks which save the space cache and inode cache may also
2184 * update ->aborted, check it.
2186 if (unlikely(READ_ONCE(cur_trans->aborted))) {
2187 ret = cur_trans->aborted;
2188 mutex_unlock(&fs_info->tree_log_mutex);
2189 mutex_unlock(&fs_info->reloc_mutex);
2190 goto scrub_continue;
2193 btrfs_prepare_extent_commit(fs_info);
2195 cur_trans = fs_info->running_transaction;
2197 btrfs_set_root_node(&fs_info->tree_root->root_item,
2198 fs_info->tree_root->node);
2199 list_add_tail(&fs_info->tree_root->dirty_list,
2200 &cur_trans->switch_commits);
2202 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2203 fs_info->chunk_root->node);
2204 list_add_tail(&fs_info->chunk_root->dirty_list,
2205 &cur_trans->switch_commits);
2207 switch_commit_roots(cur_trans);
2209 ASSERT(list_empty(&cur_trans->dirty_bgs));
2210 ASSERT(list_empty(&cur_trans->io_bgs));
2211 update_super_roots(fs_info);
2213 btrfs_set_super_log_root(fs_info->super_copy, 0);
2214 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2215 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2216 sizeof(*fs_info->super_copy));
2218 btrfs_update_commit_device_size(fs_info);
2219 btrfs_update_commit_device_bytes_used(cur_trans);
2221 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2222 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2224 btrfs_trans_release_chunk_metadata(trans);
2226 spin_lock(&fs_info->trans_lock);
2227 cur_trans->state = TRANS_STATE_UNBLOCKED;
2228 fs_info->running_transaction = NULL;
2229 spin_unlock(&fs_info->trans_lock);
2230 mutex_unlock(&fs_info->reloc_mutex);
2232 wake_up(&fs_info->transaction_wait);
2234 ret = btrfs_write_and_wait_transaction(trans);
2236 btrfs_handle_fs_error(fs_info, ret,
2237 "Error while writing out transaction");
2238 mutex_unlock(&fs_info->tree_log_mutex);
2239 goto scrub_continue;
2242 ret = write_all_supers(fs_info, 0);
2244 * the super is written, we can safely allow the tree-loggers
2245 * to go about their business
2247 mutex_unlock(&fs_info->tree_log_mutex);
2249 goto scrub_continue;
2251 btrfs_finish_extent_commit(trans);
2253 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2254 btrfs_clear_space_info_full(fs_info);
2256 fs_info->last_trans_committed = cur_trans->transid;
2258 * We needn't acquire the lock here because there is no other task
2259 * which can change it.
2261 cur_trans->state = TRANS_STATE_COMPLETED;
2262 wake_up(&cur_trans->commit_wait);
2263 clear_bit(BTRFS_FS_NEED_ASYNC_COMMIT, &fs_info->flags);
2265 spin_lock(&fs_info->trans_lock);
2266 list_del_init(&cur_trans->list);
2267 spin_unlock(&fs_info->trans_lock);
2269 btrfs_put_transaction(cur_trans);
2270 btrfs_put_transaction(cur_trans);
2272 if (trans->type & __TRANS_FREEZABLE)
2273 sb_end_intwrite(fs_info->sb);
2275 trace_btrfs_transaction_commit(trans->root);
2277 btrfs_scrub_continue(fs_info);
2279 if (current->journal_info == trans)
2280 current->journal_info = NULL;
2282 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2285 * If fs has been frozen, we can not handle delayed iputs, otherwise
2286 * it'll result in deadlock about SB_FREEZE_FS.
2288 if (current != fs_info->transaction_kthread &&
2289 current != fs_info->cleaner_kthread &&
2290 !test_bit(BTRFS_FS_FROZEN, &fs_info->flags))
2291 btrfs_run_delayed_iputs(fs_info);
2296 btrfs_scrub_continue(fs_info);
2297 cleanup_transaction:
2298 btrfs_trans_release_metadata(trans);
2299 btrfs_trans_release_chunk_metadata(trans);
2300 trans->block_rsv = NULL;
2301 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2302 if (current->journal_info == trans)
2303 current->journal_info = NULL;
2304 cleanup_transaction(trans, ret);
2310 * return < 0 if error
2311 * 0 if there are no more dead_roots at the time of call
2312 * 1 there are more to be processed, call me again
2314 * The return value indicates there are certainly more snapshots to delete, but
2315 * if there comes a new one during processing, it may return 0. We don't mind,
2316 * because btrfs_commit_super will poke cleaner thread and it will process it a
2317 * few seconds later.
2319 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2322 struct btrfs_fs_info *fs_info = root->fs_info;
2324 spin_lock(&fs_info->trans_lock);
2325 if (list_empty(&fs_info->dead_roots)) {
2326 spin_unlock(&fs_info->trans_lock);
2329 root = list_first_entry(&fs_info->dead_roots,
2330 struct btrfs_root, root_list);
2331 list_del_init(&root->root_list);
2332 spin_unlock(&fs_info->trans_lock);
2334 btrfs_debug(fs_info, "cleaner removing %llu", root->objectid);
2336 btrfs_kill_all_delayed_nodes(root);
2338 if (btrfs_header_backref_rev(root->node) <
2339 BTRFS_MIXED_BACKREF_REV)
2340 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2342 ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2344 return (ret < 0) ? 0 : 1;
2347 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2352 prev = xchg(&fs_info->pending_changes, 0);
2356 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
2358 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2361 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
2363 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2366 bit = 1 << BTRFS_PENDING_COMMIT;
2368 btrfs_debug(fs_info, "pending commit done");
2373 "unknown pending changes left 0x%lx, ignoring", prev);