2 * Copyright (C) 2007 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
20 #include <linux/sched.h>
21 #include <linux/writeback.h>
22 #include <linux/pagemap.h>
23 #include <linux/blkdev.h>
26 #include "transaction.h"
30 #define BTRFS_ROOT_TRANS_TAG 0
32 static noinline void put_transaction(struct btrfs_transaction *transaction)
34 WARN_ON(transaction->use_count == 0);
35 transaction->use_count--;
36 if (transaction->use_count == 0) {
37 list_del_init(&transaction->list);
38 memset(transaction, 0, sizeof(*transaction));
39 kmem_cache_free(btrfs_transaction_cachep, transaction);
43 static noinline void switch_commit_root(struct btrfs_root *root)
45 free_extent_buffer(root->commit_root);
46 root->commit_root = btrfs_root_node(root);
50 * either allocate a new transaction or hop into the existing one
52 static noinline int join_transaction(struct btrfs_root *root)
54 struct btrfs_transaction *cur_trans;
55 cur_trans = root->fs_info->running_transaction;
57 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
60 root->fs_info->generation++;
61 cur_trans->num_writers = 1;
62 cur_trans->num_joined = 0;
63 cur_trans->transid = root->fs_info->generation;
64 init_waitqueue_head(&cur_trans->writer_wait);
65 init_waitqueue_head(&cur_trans->commit_wait);
66 cur_trans->in_commit = 0;
67 cur_trans->blocked = 0;
68 cur_trans->use_count = 1;
69 cur_trans->commit_done = 0;
70 cur_trans->start_time = get_seconds();
72 cur_trans->delayed_refs.root.rb_node = NULL;
73 cur_trans->delayed_refs.num_entries = 0;
74 cur_trans->delayed_refs.num_heads_ready = 0;
75 cur_trans->delayed_refs.num_heads = 0;
76 cur_trans->delayed_refs.flushing = 0;
77 cur_trans->delayed_refs.run_delayed_start = 0;
78 spin_lock_init(&cur_trans->delayed_refs.lock);
80 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
81 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
82 extent_io_tree_init(&cur_trans->dirty_pages,
83 root->fs_info->btree_inode->i_mapping,
85 spin_lock(&root->fs_info->new_trans_lock);
86 root->fs_info->running_transaction = cur_trans;
87 spin_unlock(&root->fs_info->new_trans_lock);
89 cur_trans->num_writers++;
90 cur_trans->num_joined++;
97 * this does all the record keeping required to make sure that a reference
98 * counted root is properly recorded in a given transaction. This is required
99 * to make sure the old root from before we joined the transaction is deleted
100 * when the transaction commits
102 static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
103 struct btrfs_root *root)
105 if (root->ref_cows && root->last_trans < trans->transid) {
106 WARN_ON(root == root->fs_info->extent_root);
107 WARN_ON(root->commit_root != root->node);
109 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
110 (unsigned long)root->root_key.objectid,
111 BTRFS_ROOT_TRANS_TAG);
112 root->last_trans = trans->transid;
113 btrfs_init_reloc_root(trans, root);
118 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
119 struct btrfs_root *root)
124 mutex_lock(&root->fs_info->trans_mutex);
125 if (root->last_trans == trans->transid) {
126 mutex_unlock(&root->fs_info->trans_mutex);
130 record_root_in_trans(trans, root);
131 mutex_unlock(&root->fs_info->trans_mutex);
135 /* wait for commit against the current transaction to become unblocked
136 * when this is done, it is safe to start a new transaction, but the current
137 * transaction might not be fully on disk.
139 static void wait_current_trans(struct btrfs_root *root)
141 struct btrfs_transaction *cur_trans;
143 cur_trans = root->fs_info->running_transaction;
144 if (cur_trans && cur_trans->blocked) {
146 cur_trans->use_count++;
148 prepare_to_wait(&root->fs_info->transaction_wait, &wait,
149 TASK_UNINTERRUPTIBLE);
150 if (cur_trans->blocked) {
151 mutex_unlock(&root->fs_info->trans_mutex);
153 mutex_lock(&root->fs_info->trans_mutex);
154 finish_wait(&root->fs_info->transaction_wait,
157 finish_wait(&root->fs_info->transaction_wait,
162 put_transaction(cur_trans);
166 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
167 int num_blocks, int wait)
169 struct btrfs_trans_handle *h =
170 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
173 mutex_lock(&root->fs_info->trans_mutex);
174 if (!root->fs_info->log_root_recovering &&
175 ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
176 wait_current_trans(root);
177 ret = join_transaction(root);
180 h->transid = root->fs_info->running_transaction->transid;
181 h->transaction = root->fs_info->running_transaction;
182 h->blocks_reserved = num_blocks;
185 h->alloc_exclude_nr = 0;
186 h->alloc_exclude_start = 0;
187 h->delayed_ref_updates = 0;
189 root->fs_info->running_transaction->use_count++;
190 record_root_in_trans(h, root);
191 mutex_unlock(&root->fs_info->trans_mutex);
195 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
198 return start_transaction(root, num_blocks, 1);
200 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
203 return start_transaction(root, num_blocks, 0);
206 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
209 return start_transaction(r, num_blocks, 2);
212 /* wait for a transaction commit to be fully complete */
213 static noinline int wait_for_commit(struct btrfs_root *root,
214 struct btrfs_transaction *commit)
217 mutex_lock(&root->fs_info->trans_mutex);
218 while (!commit->commit_done) {
219 prepare_to_wait(&commit->commit_wait, &wait,
220 TASK_UNINTERRUPTIBLE);
221 if (commit->commit_done)
223 mutex_unlock(&root->fs_info->trans_mutex);
225 mutex_lock(&root->fs_info->trans_mutex);
227 mutex_unlock(&root->fs_info->trans_mutex);
228 finish_wait(&commit->commit_wait, &wait);
234 * rate limit against the drop_snapshot code. This helps to slow down new
235 * operations if the drop_snapshot code isn't able to keep up.
237 static void throttle_on_drops(struct btrfs_root *root)
239 struct btrfs_fs_info *info = root->fs_info;
240 int harder_count = 0;
243 if (atomic_read(&info->throttles)) {
246 thr = atomic_read(&info->throttle_gen);
249 prepare_to_wait(&info->transaction_throttle,
250 &wait, TASK_UNINTERRUPTIBLE);
251 if (!atomic_read(&info->throttles)) {
252 finish_wait(&info->transaction_throttle, &wait);
256 finish_wait(&info->transaction_throttle, &wait);
257 } while (thr == atomic_read(&info->throttle_gen));
260 if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
264 if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
268 if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
275 void btrfs_throttle(struct btrfs_root *root)
277 mutex_lock(&root->fs_info->trans_mutex);
278 if (!root->fs_info->open_ioctl_trans)
279 wait_current_trans(root);
280 mutex_unlock(&root->fs_info->trans_mutex);
283 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
284 struct btrfs_root *root, int throttle)
286 struct btrfs_transaction *cur_trans;
287 struct btrfs_fs_info *info = root->fs_info;
291 unsigned long cur = trans->delayed_ref_updates;
292 trans->delayed_ref_updates = 0;
294 trans->transaction->delayed_refs.num_heads_ready > 64) {
295 trans->delayed_ref_updates = 0;
298 * do a full flush if the transaction is trying
301 if (trans->transaction->delayed_refs.flushing)
303 btrfs_run_delayed_refs(trans, root, cur);
310 mutex_lock(&info->trans_mutex);
311 cur_trans = info->running_transaction;
312 WARN_ON(cur_trans != trans->transaction);
313 WARN_ON(cur_trans->num_writers < 1);
314 cur_trans->num_writers--;
316 if (waitqueue_active(&cur_trans->writer_wait))
317 wake_up(&cur_trans->writer_wait);
318 put_transaction(cur_trans);
319 mutex_unlock(&info->trans_mutex);
320 memset(trans, 0, sizeof(*trans));
321 kmem_cache_free(btrfs_trans_handle_cachep, trans);
326 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
327 struct btrfs_root *root)
329 return __btrfs_end_transaction(trans, root, 0);
332 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
333 struct btrfs_root *root)
335 return __btrfs_end_transaction(trans, root, 1);
339 * when btree blocks are allocated, they have some corresponding bits set for
340 * them in one of two extent_io trees. This is used to make sure all of
341 * those extents are on disk for transaction or log commit
343 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
344 struct extent_io_tree *dirty_pages)
350 struct inode *btree_inode = root->fs_info->btree_inode;
356 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
360 while (start <= end) {
363 index = start >> PAGE_CACHE_SHIFT;
364 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
365 page = find_get_page(btree_inode->i_mapping, index);
369 btree_lock_page_hook(page);
370 if (!page->mapping) {
372 page_cache_release(page);
376 if (PageWriteback(page)) {
378 wait_on_page_writeback(page);
381 page_cache_release(page);
385 err = write_one_page(page, 0);
388 page_cache_release(page);
392 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
397 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
398 while (start <= end) {
399 index = start >> PAGE_CACHE_SHIFT;
400 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
401 page = find_get_page(btree_inode->i_mapping, index);
404 if (PageDirty(page)) {
405 btree_lock_page_hook(page);
406 wait_on_page_writeback(page);
407 err = write_one_page(page, 0);
411 wait_on_page_writeback(page);
412 page_cache_release(page);
421 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
422 struct btrfs_root *root)
424 if (!trans || !trans->transaction) {
425 struct inode *btree_inode;
426 btree_inode = root->fs_info->btree_inode;
427 return filemap_write_and_wait(btree_inode->i_mapping);
429 return btrfs_write_and_wait_marked_extents(root,
430 &trans->transaction->dirty_pages);
434 * this is used to update the root pointer in the tree of tree roots.
436 * But, in the case of the extent allocation tree, updating the root
437 * pointer may allocate blocks which may change the root of the extent
440 * So, this loops and repeats and makes sure the cowonly root didn't
441 * change while the root pointer was being updated in the metadata.
443 static int update_cowonly_root(struct btrfs_trans_handle *trans,
444 struct btrfs_root *root)
448 struct btrfs_root *tree_root = root->fs_info->tree_root;
450 btrfs_write_dirty_block_groups(trans, root);
453 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
454 if (old_root_bytenr == root->node->start)
457 btrfs_set_root_node(&root->root_item, root->node);
458 ret = btrfs_update_root(trans, tree_root,
463 ret = btrfs_write_dirty_block_groups(trans, root);
467 if (root != root->fs_info->extent_root)
468 switch_commit_root(root);
474 * update all the cowonly tree roots on disk
476 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
477 struct btrfs_root *root)
479 struct btrfs_fs_info *fs_info = root->fs_info;
480 struct list_head *next;
481 struct extent_buffer *eb;
484 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
487 eb = btrfs_lock_root_node(fs_info->tree_root);
488 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
489 btrfs_tree_unlock(eb);
490 free_extent_buffer(eb);
492 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
495 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
496 next = fs_info->dirty_cowonly_roots.next;
498 root = list_entry(next, struct btrfs_root, dirty_list);
500 update_cowonly_root(trans, root);
503 down_write(&fs_info->extent_commit_sem);
504 switch_commit_root(fs_info->extent_root);
505 up_write(&fs_info->extent_commit_sem);
511 * dead roots are old snapshots that need to be deleted. This allocates
512 * a dirty root struct and adds it into the list of dead roots that need to
515 int btrfs_add_dead_root(struct btrfs_root *root)
517 mutex_lock(&root->fs_info->trans_mutex);
518 list_add(&root->root_list, &root->fs_info->dead_roots);
519 mutex_unlock(&root->fs_info->trans_mutex);
524 * update all the cowonly tree roots on disk
526 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
527 struct btrfs_root *root)
529 struct btrfs_root *gang[8];
530 struct btrfs_fs_info *fs_info = root->fs_info;
536 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
539 BTRFS_ROOT_TRANS_TAG);
542 for (i = 0; i < ret; i++) {
544 radix_tree_tag_clear(&fs_info->fs_roots_radix,
545 (unsigned long)root->root_key.objectid,
546 BTRFS_ROOT_TRANS_TAG);
548 btrfs_free_log(trans, root);
549 btrfs_update_reloc_root(trans, root);
551 if (root->commit_root != root->node) {
552 switch_commit_root(root);
553 btrfs_set_root_node(&root->root_item,
557 err = btrfs_update_root(trans, fs_info->tree_root,
568 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
569 * otherwise every leaf in the btree is read and defragged.
571 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
573 struct btrfs_fs_info *info = root->fs_info;
575 struct btrfs_trans_handle *trans;
579 if (root->defrag_running)
581 trans = btrfs_start_transaction(root, 1);
583 root->defrag_running = 1;
584 ret = btrfs_defrag_leaves(trans, root, cacheonly);
585 nr = trans->blocks_used;
586 btrfs_end_transaction(trans, root);
587 btrfs_btree_balance_dirty(info->tree_root, nr);
590 trans = btrfs_start_transaction(root, 1);
591 if (root->fs_info->closing || ret != -EAGAIN)
594 root->defrag_running = 0;
596 btrfs_end_transaction(trans, root);
602 * when dropping snapshots, we generate a ton of delayed refs, and it makes
603 * sense not to join the transaction while it is trying to flush the current
604 * queue of delayed refs out.
606 * This is used by the drop snapshot code only
608 static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
612 mutex_lock(&info->trans_mutex);
613 while (info->running_transaction &&
614 info->running_transaction->delayed_refs.flushing) {
615 prepare_to_wait(&info->transaction_wait, &wait,
616 TASK_UNINTERRUPTIBLE);
617 mutex_unlock(&info->trans_mutex);
621 mutex_lock(&info->trans_mutex);
622 finish_wait(&info->transaction_wait, &wait);
624 mutex_unlock(&info->trans_mutex);
629 * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
632 int btrfs_drop_dead_root(struct btrfs_root *root)
634 struct btrfs_trans_handle *trans;
635 struct btrfs_root *tree_root = root->fs_info->tree_root;
641 * we don't want to jump in and create a bunch of
642 * delayed refs if the transaction is starting to close
644 wait_transaction_pre_flush(tree_root->fs_info);
645 trans = btrfs_start_transaction(tree_root, 1);
648 * we've joined a transaction, make sure it isn't
651 if (trans->transaction->delayed_refs.flushing) {
652 btrfs_end_transaction(trans, tree_root);
656 ret = btrfs_drop_snapshot(trans, root);
660 ret = btrfs_update_root(trans, tree_root,
666 nr = trans->blocks_used;
667 ret = btrfs_end_transaction(trans, tree_root);
670 btrfs_btree_balance_dirty(tree_root, nr);
675 ret = btrfs_del_root(trans, tree_root, &root->root_key);
678 nr = trans->blocks_used;
679 ret = btrfs_end_transaction(trans, tree_root);
682 free_extent_buffer(root->node);
683 free_extent_buffer(root->commit_root);
686 btrfs_btree_balance_dirty(tree_root, nr);
692 * new snapshots need to be created at a very specific time in the
693 * transaction commit. This does the actual creation
695 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
696 struct btrfs_fs_info *fs_info,
697 struct btrfs_pending_snapshot *pending)
699 struct btrfs_key key;
700 struct btrfs_root_item *new_root_item;
701 struct btrfs_root *tree_root = fs_info->tree_root;
702 struct btrfs_root *root = pending->root;
703 struct extent_buffer *tmp;
704 struct extent_buffer *old;
708 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
709 if (!new_root_item) {
713 ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
717 record_root_in_trans(trans, root);
718 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
719 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
721 key.objectid = objectid;
722 /* record when the snapshot was created in key.offset */
723 key.offset = trans->transid;
724 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
726 old = btrfs_lock_root_node(root);
727 btrfs_cow_block(trans, root, old, NULL, 0, &old);
728 btrfs_set_lock_blocking(old);
730 btrfs_copy_root(trans, root, old, &tmp, objectid);
731 btrfs_tree_unlock(old);
732 free_extent_buffer(old);
734 btrfs_set_root_node(new_root_item, tmp);
735 ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
737 btrfs_tree_unlock(tmp);
738 free_extent_buffer(tmp);
742 key.offset = (u64)-1;
743 memcpy(&pending->root_key, &key, sizeof(key));
745 kfree(new_root_item);
749 static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
750 struct btrfs_pending_snapshot *pending)
755 struct btrfs_trans_handle *trans;
756 struct inode *parent_inode;
758 struct btrfs_root *parent_root;
760 parent_inode = pending->dentry->d_parent->d_inode;
761 parent_root = BTRFS_I(parent_inode)->root;
762 trans = btrfs_join_transaction(parent_root, 1);
765 * insert the directory item
767 namelen = strlen(pending->name);
768 ret = btrfs_set_inode_index(parent_inode, &index);
769 ret = btrfs_insert_dir_item(trans, parent_root,
770 pending->name, namelen,
772 &pending->root_key, BTRFS_FT_DIR, index);
777 btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
778 ret = btrfs_update_inode(trans, parent_root, parent_inode);
781 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
782 pending->root_key.objectid,
783 parent_root->root_key.objectid,
784 parent_inode->i_ino, index, pending->name,
789 inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
790 d_instantiate(pending->dentry, inode);
792 btrfs_end_transaction(trans, fs_info->fs_root);
797 * create all the snapshots we've scheduled for creation
799 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
800 struct btrfs_fs_info *fs_info)
802 struct btrfs_pending_snapshot *pending;
803 struct list_head *head = &trans->transaction->pending_snapshots;
806 list_for_each_entry(pending, head, list) {
807 ret = create_pending_snapshot(trans, fs_info, pending);
813 static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
814 struct btrfs_fs_info *fs_info)
816 struct btrfs_pending_snapshot *pending;
817 struct list_head *head = &trans->transaction->pending_snapshots;
820 while (!list_empty(head)) {
821 pending = list_entry(head->next,
822 struct btrfs_pending_snapshot, list);
823 ret = finish_pending_snapshot(fs_info, pending);
825 list_del(&pending->list);
826 kfree(pending->name);
832 static void update_super_roots(struct btrfs_root *root)
834 struct btrfs_root_item *root_item;
835 struct btrfs_super_block *super;
837 super = &root->fs_info->super_copy;
839 root_item = &root->fs_info->chunk_root->root_item;
840 super->chunk_root = root_item->bytenr;
841 super->chunk_root_generation = root_item->generation;
842 super->chunk_root_level = root_item->level;
844 root_item = &root->fs_info->tree_root->root_item;
845 super->root = root_item->bytenr;
846 super->generation = root_item->generation;
847 super->root_level = root_item->level;
850 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
853 spin_lock(&info->new_trans_lock);
854 if (info->running_transaction)
855 ret = info->running_transaction->in_commit;
856 spin_unlock(&info->new_trans_lock);
860 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
861 struct btrfs_root *root)
863 unsigned long joined = 0;
864 unsigned long timeout = 1;
865 struct btrfs_transaction *cur_trans;
866 struct btrfs_transaction *prev_trans = NULL;
870 unsigned long now = get_seconds();
871 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
873 btrfs_run_ordered_operations(root, 0);
875 /* make a pass through all the delayed refs we have so far
876 * any runnings procs may add more while we are here
878 ret = btrfs_run_delayed_refs(trans, root, 0);
881 cur_trans = trans->transaction;
883 * set the flushing flag so procs in this transaction have to
884 * start sending their work down.
886 cur_trans->delayed_refs.flushing = 1;
888 ret = btrfs_run_delayed_refs(trans, root, 0);
891 mutex_lock(&root->fs_info->trans_mutex);
892 if (cur_trans->in_commit) {
893 cur_trans->use_count++;
894 mutex_unlock(&root->fs_info->trans_mutex);
895 btrfs_end_transaction(trans, root);
897 ret = wait_for_commit(root, cur_trans);
900 mutex_lock(&root->fs_info->trans_mutex);
901 put_transaction(cur_trans);
902 mutex_unlock(&root->fs_info->trans_mutex);
907 trans->transaction->in_commit = 1;
908 trans->transaction->blocked = 1;
909 if (cur_trans->list.prev != &root->fs_info->trans_list) {
910 prev_trans = list_entry(cur_trans->list.prev,
911 struct btrfs_transaction, list);
912 if (!prev_trans->commit_done) {
913 prev_trans->use_count++;
914 mutex_unlock(&root->fs_info->trans_mutex);
916 wait_for_commit(root, prev_trans);
918 mutex_lock(&root->fs_info->trans_mutex);
919 put_transaction(prev_trans);
923 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
927 int snap_pending = 0;
928 joined = cur_trans->num_joined;
929 if (!list_empty(&trans->transaction->pending_snapshots))
932 WARN_ON(cur_trans != trans->transaction);
933 prepare_to_wait(&cur_trans->writer_wait, &wait,
934 TASK_UNINTERRUPTIBLE);
936 if (cur_trans->num_writers > 1)
937 timeout = MAX_SCHEDULE_TIMEOUT;
938 else if (should_grow)
941 mutex_unlock(&root->fs_info->trans_mutex);
943 if (flush_on_commit) {
944 btrfs_start_delalloc_inodes(root);
945 ret = btrfs_wait_ordered_extents(root, 0);
947 } else if (snap_pending) {
948 ret = btrfs_wait_ordered_extents(root, 1);
953 * rename don't use btrfs_join_transaction, so, once we
954 * set the transaction to blocked above, we aren't going
955 * to get any new ordered operations. We can safely run
956 * it here and no for sure that nothing new will be added
959 btrfs_run_ordered_operations(root, 1);
962 if (cur_trans->num_writers > 1 || should_grow)
963 schedule_timeout(timeout);
965 mutex_lock(&root->fs_info->trans_mutex);
966 finish_wait(&cur_trans->writer_wait, &wait);
967 } while (cur_trans->num_writers > 1 ||
968 (should_grow && cur_trans->num_joined != joined));
970 ret = create_pending_snapshots(trans, root->fs_info);
973 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
976 WARN_ON(cur_trans != trans->transaction);
978 /* btrfs_commit_tree_roots is responsible for getting the
979 * various roots consistent with each other. Every pointer
980 * in the tree of tree roots has to point to the most up to date
981 * root for every subvolume and other tree. So, we have to keep
982 * the tree logging code from jumping in and changing any
985 * At this point in the commit, there can't be any tree-log
986 * writers, but a little lower down we drop the trans mutex
987 * and let new people in. By holding the tree_log_mutex
988 * from now until after the super is written, we avoid races
989 * with the tree-log code.
991 mutex_lock(&root->fs_info->tree_log_mutex);
993 ret = commit_fs_roots(trans, root);
996 /* commit_fs_roots gets rid of all the tree log roots, it is now
997 * safe to free the root of tree log roots
999 btrfs_free_log_root_tree(trans, root->fs_info);
1001 ret = commit_cowonly_roots(trans, root);
1004 btrfs_prepare_extent_commit(trans, root);
1006 cur_trans = root->fs_info->running_transaction;
1007 spin_lock(&root->fs_info->new_trans_lock);
1008 root->fs_info->running_transaction = NULL;
1009 spin_unlock(&root->fs_info->new_trans_lock);
1011 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1012 root->fs_info->tree_root->node);
1013 switch_commit_root(root->fs_info->tree_root);
1015 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1016 root->fs_info->chunk_root->node);
1017 switch_commit_root(root->fs_info->chunk_root);
1019 update_super_roots(root);
1021 if (!root->fs_info->log_root_recovering) {
1022 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1023 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1026 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1027 sizeof(root->fs_info->super_copy));
1029 trans->transaction->blocked = 0;
1031 wake_up(&root->fs_info->transaction_wait);
1033 mutex_unlock(&root->fs_info->trans_mutex);
1034 ret = btrfs_write_and_wait_transaction(trans, root);
1036 write_ctree_super(trans, root, 0);
1039 * the super is written, we can safely allow the tree-loggers
1040 * to go about their business
1042 mutex_unlock(&root->fs_info->tree_log_mutex);
1044 btrfs_finish_extent_commit(trans, root);
1046 /* do the directory inserts of any pending snapshot creations */
1047 finish_pending_snapshots(trans, root->fs_info);
1049 mutex_lock(&root->fs_info->trans_mutex);
1051 cur_trans->commit_done = 1;
1053 root->fs_info->last_trans_committed = cur_trans->transid;
1055 wake_up(&cur_trans->commit_wait);
1057 put_transaction(cur_trans);
1058 put_transaction(cur_trans);
1060 mutex_unlock(&root->fs_info->trans_mutex);
1062 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1067 * interface function to delete all the snapshots we have scheduled for deletion
1069 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1072 struct btrfs_fs_info *fs_info = root->fs_info;
1074 mutex_lock(&fs_info->trans_mutex);
1075 list_splice_init(&fs_info->dead_roots, &list);
1076 mutex_unlock(&fs_info->trans_mutex);
1078 while (!list_empty(&list)) {
1079 root = list_entry(list.next, struct btrfs_root, root_list);
1080 list_del(&root->root_list);
1082 if (btrfs_header_backref_rev(root->node) <
1083 BTRFS_MIXED_BACKREF_REV)
1084 btrfs_drop_snapshot(root, 0);
1086 btrfs_drop_snapshot(root, 1);