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/slab.h>
21 #include <linux/sched.h>
22 #include <linux/writeback.h>
23 #include <linux/pagemap.h>
24 #include <linux/blkdev.h>
27 #include "transaction.h"
31 #define BTRFS_ROOT_TRANS_TAG 0
33 static noinline void put_transaction(struct btrfs_transaction *transaction)
35 WARN_ON(transaction->use_count == 0);
36 transaction->use_count--;
37 if (transaction->use_count == 0) {
38 list_del_init(&transaction->list);
39 memset(transaction, 0, sizeof(*transaction));
40 kmem_cache_free(btrfs_transaction_cachep, transaction);
44 static noinline void switch_commit_root(struct btrfs_root *root)
46 free_extent_buffer(root->commit_root);
47 root->commit_root = btrfs_root_node(root);
51 * either allocate a new transaction or hop into the existing one
53 static noinline int join_transaction(struct btrfs_root *root)
55 struct btrfs_transaction *cur_trans;
56 cur_trans = root->fs_info->running_transaction;
58 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
61 root->fs_info->generation++;
62 cur_trans->num_writers = 1;
63 cur_trans->num_joined = 0;
64 cur_trans->transid = root->fs_info->generation;
65 init_waitqueue_head(&cur_trans->writer_wait);
66 init_waitqueue_head(&cur_trans->commit_wait);
67 cur_trans->in_commit = 0;
68 cur_trans->blocked = 0;
69 cur_trans->use_count = 1;
70 cur_trans->commit_done = 0;
71 cur_trans->start_time = get_seconds();
73 cur_trans->delayed_refs.root = RB_ROOT;
74 cur_trans->delayed_refs.num_entries = 0;
75 cur_trans->delayed_refs.num_heads_ready = 0;
76 cur_trans->delayed_refs.num_heads = 0;
77 cur_trans->delayed_refs.flushing = 0;
78 cur_trans->delayed_refs.run_delayed_start = 0;
79 spin_lock_init(&cur_trans->delayed_refs.lock);
81 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
82 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
83 extent_io_tree_init(&cur_trans->dirty_pages,
84 root->fs_info->btree_inode->i_mapping,
86 spin_lock(&root->fs_info->new_trans_lock);
87 root->fs_info->running_transaction = cur_trans;
88 spin_unlock(&root->fs_info->new_trans_lock);
90 cur_trans->num_writers++;
91 cur_trans->num_joined++;
98 * this does all the record keeping required to make sure that a reference
99 * counted root is properly recorded in a given transaction. This is required
100 * to make sure the old root from before we joined the transaction is deleted
101 * when the transaction commits
103 static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
104 struct btrfs_root *root)
106 if (root->ref_cows && root->last_trans < trans->transid) {
107 WARN_ON(root == root->fs_info->extent_root);
108 WARN_ON(root->commit_root != root->node);
110 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
111 (unsigned long)root->root_key.objectid,
112 BTRFS_ROOT_TRANS_TAG);
113 root->last_trans = trans->transid;
114 btrfs_init_reloc_root(trans, root);
119 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
120 struct btrfs_root *root)
125 mutex_lock(&root->fs_info->trans_mutex);
126 if (root->last_trans == trans->transid) {
127 mutex_unlock(&root->fs_info->trans_mutex);
131 record_root_in_trans(trans, root);
132 mutex_unlock(&root->fs_info->trans_mutex);
136 /* wait for commit against the current transaction to become unblocked
137 * when this is done, it is safe to start a new transaction, but the current
138 * transaction might not be fully on disk.
140 static void wait_current_trans(struct btrfs_root *root)
142 struct btrfs_transaction *cur_trans;
144 cur_trans = root->fs_info->running_transaction;
145 if (cur_trans && cur_trans->blocked) {
147 cur_trans->use_count++;
149 prepare_to_wait(&root->fs_info->transaction_wait, &wait,
150 TASK_UNINTERRUPTIBLE);
151 if (cur_trans->blocked) {
152 mutex_unlock(&root->fs_info->trans_mutex);
154 mutex_lock(&root->fs_info->trans_mutex);
155 finish_wait(&root->fs_info->transaction_wait,
158 finish_wait(&root->fs_info->transaction_wait,
163 put_transaction(cur_trans);
167 enum btrfs_trans_type {
173 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
174 int num_blocks, int type)
176 struct btrfs_trans_handle *h =
177 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
180 mutex_lock(&root->fs_info->trans_mutex);
181 if (!root->fs_info->log_root_recovering &&
182 ((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
183 type == TRANS_USERSPACE))
184 wait_current_trans(root);
185 ret = join_transaction(root);
188 h->transid = root->fs_info->running_transaction->transid;
189 h->transaction = root->fs_info->running_transaction;
190 h->blocks_reserved = num_blocks;
193 h->alloc_exclude_nr = 0;
194 h->alloc_exclude_start = 0;
195 h->delayed_ref_updates = 0;
197 if (!current->journal_info && type != TRANS_USERSPACE)
198 current->journal_info = h;
200 root->fs_info->running_transaction->use_count++;
201 record_root_in_trans(h, root);
202 mutex_unlock(&root->fs_info->trans_mutex);
206 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
209 return start_transaction(root, num_blocks, TRANS_START);
211 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
214 return start_transaction(root, num_blocks, TRANS_JOIN);
217 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
220 return start_transaction(r, num_blocks, TRANS_USERSPACE);
223 /* wait for a transaction commit to be fully complete */
224 static noinline int wait_for_commit(struct btrfs_root *root,
225 struct btrfs_transaction *commit)
228 mutex_lock(&root->fs_info->trans_mutex);
229 while (!commit->commit_done) {
230 prepare_to_wait(&commit->commit_wait, &wait,
231 TASK_UNINTERRUPTIBLE);
232 if (commit->commit_done)
234 mutex_unlock(&root->fs_info->trans_mutex);
236 mutex_lock(&root->fs_info->trans_mutex);
238 mutex_unlock(&root->fs_info->trans_mutex);
239 finish_wait(&commit->commit_wait, &wait);
245 * rate limit against the drop_snapshot code. This helps to slow down new
246 * operations if the drop_snapshot code isn't able to keep up.
248 static void throttle_on_drops(struct btrfs_root *root)
250 struct btrfs_fs_info *info = root->fs_info;
251 int harder_count = 0;
254 if (atomic_read(&info->throttles)) {
257 thr = atomic_read(&info->throttle_gen);
260 prepare_to_wait(&info->transaction_throttle,
261 &wait, TASK_UNINTERRUPTIBLE);
262 if (!atomic_read(&info->throttles)) {
263 finish_wait(&info->transaction_throttle, &wait);
267 finish_wait(&info->transaction_throttle, &wait);
268 } while (thr == atomic_read(&info->throttle_gen));
271 if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
275 if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
279 if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
286 void btrfs_throttle(struct btrfs_root *root)
288 mutex_lock(&root->fs_info->trans_mutex);
289 if (!root->fs_info->open_ioctl_trans)
290 wait_current_trans(root);
291 mutex_unlock(&root->fs_info->trans_mutex);
294 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
295 struct btrfs_root *root, int throttle)
297 struct btrfs_transaction *cur_trans;
298 struct btrfs_fs_info *info = root->fs_info;
302 unsigned long cur = trans->delayed_ref_updates;
303 trans->delayed_ref_updates = 0;
305 trans->transaction->delayed_refs.num_heads_ready > 64) {
306 trans->delayed_ref_updates = 0;
309 * do a full flush if the transaction is trying
312 if (trans->transaction->delayed_refs.flushing)
314 btrfs_run_delayed_refs(trans, root, cur);
321 mutex_lock(&info->trans_mutex);
322 cur_trans = info->running_transaction;
323 WARN_ON(cur_trans != trans->transaction);
324 WARN_ON(cur_trans->num_writers < 1);
325 cur_trans->num_writers--;
327 if (waitqueue_active(&cur_trans->writer_wait))
328 wake_up(&cur_trans->writer_wait);
329 put_transaction(cur_trans);
330 mutex_unlock(&info->trans_mutex);
332 if (current->journal_info == trans)
333 current->journal_info = NULL;
334 memset(trans, 0, sizeof(*trans));
335 kmem_cache_free(btrfs_trans_handle_cachep, trans);
338 btrfs_run_delayed_iputs(root);
343 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
344 struct btrfs_root *root)
346 return __btrfs_end_transaction(trans, root, 0);
349 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
350 struct btrfs_root *root)
352 return __btrfs_end_transaction(trans, root, 1);
356 * when btree blocks are allocated, they have some corresponding bits set for
357 * them in one of two extent_io trees. This is used to make sure all of
358 * those extents are sent to disk but does not wait on them
360 int btrfs_write_marked_extents(struct btrfs_root *root,
361 struct extent_io_tree *dirty_pages, int mark)
367 struct inode *btree_inode = root->fs_info->btree_inode;
373 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
377 while (start <= end) {
380 index = start >> PAGE_CACHE_SHIFT;
381 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
382 page = find_get_page(btree_inode->i_mapping, index);
386 btree_lock_page_hook(page);
387 if (!page->mapping) {
389 page_cache_release(page);
393 if (PageWriteback(page)) {
395 wait_on_page_writeback(page);
398 page_cache_release(page);
402 err = write_one_page(page, 0);
405 page_cache_release(page);
414 * when btree blocks are allocated, they have some corresponding bits set for
415 * them in one of two extent_io trees. This is used to make sure all of
416 * those extents are on disk for transaction or log commit. We wait
417 * on all the pages and clear them from the dirty pages state tree
419 int btrfs_wait_marked_extents(struct btrfs_root *root,
420 struct extent_io_tree *dirty_pages, int mark)
426 struct inode *btree_inode = root->fs_info->btree_inode;
432 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
437 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
438 while (start <= end) {
439 index = start >> PAGE_CACHE_SHIFT;
440 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
441 page = find_get_page(btree_inode->i_mapping, index);
444 if (PageDirty(page)) {
445 btree_lock_page_hook(page);
446 wait_on_page_writeback(page);
447 err = write_one_page(page, 0);
451 wait_on_page_writeback(page);
452 page_cache_release(page);
462 * when btree blocks are allocated, they have some corresponding bits set for
463 * them in one of two extent_io trees. This is used to make sure all of
464 * those extents are on disk for transaction or log commit
466 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
467 struct extent_io_tree *dirty_pages, int mark)
472 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
473 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
477 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
478 struct btrfs_root *root)
480 if (!trans || !trans->transaction) {
481 struct inode *btree_inode;
482 btree_inode = root->fs_info->btree_inode;
483 return filemap_write_and_wait(btree_inode->i_mapping);
485 return btrfs_write_and_wait_marked_extents(root,
486 &trans->transaction->dirty_pages,
491 * this is used to update the root pointer in the tree of tree roots.
493 * But, in the case of the extent allocation tree, updating the root
494 * pointer may allocate blocks which may change the root of the extent
497 * So, this loops and repeats and makes sure the cowonly root didn't
498 * change while the root pointer was being updated in the metadata.
500 static int update_cowonly_root(struct btrfs_trans_handle *trans,
501 struct btrfs_root *root)
506 struct btrfs_root *tree_root = root->fs_info->tree_root;
508 old_root_used = btrfs_root_used(&root->root_item);
509 btrfs_write_dirty_block_groups(trans, root);
512 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
513 if (old_root_bytenr == root->node->start &&
514 old_root_used == btrfs_root_used(&root->root_item))
517 btrfs_set_root_node(&root->root_item, root->node);
518 ret = btrfs_update_root(trans, tree_root,
523 old_root_used = btrfs_root_used(&root->root_item);
524 ret = btrfs_write_dirty_block_groups(trans, root);
528 if (root != root->fs_info->extent_root)
529 switch_commit_root(root);
535 * update all the cowonly tree roots on disk
537 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
538 struct btrfs_root *root)
540 struct btrfs_fs_info *fs_info = root->fs_info;
541 struct list_head *next;
542 struct extent_buffer *eb;
545 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
548 eb = btrfs_lock_root_node(fs_info->tree_root);
549 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
550 btrfs_tree_unlock(eb);
551 free_extent_buffer(eb);
553 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
556 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
557 next = fs_info->dirty_cowonly_roots.next;
559 root = list_entry(next, struct btrfs_root, dirty_list);
561 update_cowonly_root(trans, root);
564 down_write(&fs_info->extent_commit_sem);
565 switch_commit_root(fs_info->extent_root);
566 up_write(&fs_info->extent_commit_sem);
572 * dead roots are old snapshots that need to be deleted. This allocates
573 * a dirty root struct and adds it into the list of dead roots that need to
576 int btrfs_add_dead_root(struct btrfs_root *root)
578 mutex_lock(&root->fs_info->trans_mutex);
579 list_add(&root->root_list, &root->fs_info->dead_roots);
580 mutex_unlock(&root->fs_info->trans_mutex);
585 * update all the cowonly tree roots on disk
587 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
588 struct btrfs_root *root)
590 struct btrfs_root *gang[8];
591 struct btrfs_fs_info *fs_info = root->fs_info;
597 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
600 BTRFS_ROOT_TRANS_TAG);
603 for (i = 0; i < ret; i++) {
605 radix_tree_tag_clear(&fs_info->fs_roots_radix,
606 (unsigned long)root->root_key.objectid,
607 BTRFS_ROOT_TRANS_TAG);
609 btrfs_free_log(trans, root);
610 btrfs_update_reloc_root(trans, root);
612 if (root->commit_root != root->node) {
613 switch_commit_root(root);
614 btrfs_set_root_node(&root->root_item,
618 err = btrfs_update_root(trans, fs_info->tree_root,
629 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
630 * otherwise every leaf in the btree is read and defragged.
632 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
634 struct btrfs_fs_info *info = root->fs_info;
636 struct btrfs_trans_handle *trans;
640 if (root->defrag_running)
642 trans = btrfs_start_transaction(root, 1);
644 root->defrag_running = 1;
645 ret = btrfs_defrag_leaves(trans, root, cacheonly);
646 nr = trans->blocks_used;
647 btrfs_end_transaction(trans, root);
648 btrfs_btree_balance_dirty(info->tree_root, nr);
651 trans = btrfs_start_transaction(root, 1);
652 if (root->fs_info->closing || ret != -EAGAIN)
655 root->defrag_running = 0;
657 btrfs_end_transaction(trans, root);
663 * when dropping snapshots, we generate a ton of delayed refs, and it makes
664 * sense not to join the transaction while it is trying to flush the current
665 * queue of delayed refs out.
667 * This is used by the drop snapshot code only
669 static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
673 mutex_lock(&info->trans_mutex);
674 while (info->running_transaction &&
675 info->running_transaction->delayed_refs.flushing) {
676 prepare_to_wait(&info->transaction_wait, &wait,
677 TASK_UNINTERRUPTIBLE);
678 mutex_unlock(&info->trans_mutex);
682 mutex_lock(&info->trans_mutex);
683 finish_wait(&info->transaction_wait, &wait);
685 mutex_unlock(&info->trans_mutex);
690 * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
693 int btrfs_drop_dead_root(struct btrfs_root *root)
695 struct btrfs_trans_handle *trans;
696 struct btrfs_root *tree_root = root->fs_info->tree_root;
702 * we don't want to jump in and create a bunch of
703 * delayed refs if the transaction is starting to close
705 wait_transaction_pre_flush(tree_root->fs_info);
706 trans = btrfs_start_transaction(tree_root, 1);
709 * we've joined a transaction, make sure it isn't
712 if (trans->transaction->delayed_refs.flushing) {
713 btrfs_end_transaction(trans, tree_root);
717 ret = btrfs_drop_snapshot(trans, root);
721 ret = btrfs_update_root(trans, tree_root,
727 nr = trans->blocks_used;
728 ret = btrfs_end_transaction(trans, tree_root);
731 btrfs_btree_balance_dirty(tree_root, nr);
736 ret = btrfs_del_root(trans, tree_root, &root->root_key);
739 nr = trans->blocks_used;
740 ret = btrfs_end_transaction(trans, tree_root);
743 free_extent_buffer(root->node);
744 free_extent_buffer(root->commit_root);
747 btrfs_btree_balance_dirty(tree_root, nr);
753 * new snapshots need to be created at a very specific time in the
754 * transaction commit. This does the actual creation
756 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
757 struct btrfs_fs_info *fs_info,
758 struct btrfs_pending_snapshot *pending)
760 struct btrfs_key key;
761 struct btrfs_root_item *new_root_item;
762 struct btrfs_root *tree_root = fs_info->tree_root;
763 struct btrfs_root *root = pending->root;
764 struct extent_buffer *tmp;
765 struct extent_buffer *old;
769 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
770 if (!new_root_item) {
774 ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
778 record_root_in_trans(trans, root);
779 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
780 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
782 key.objectid = objectid;
783 /* record when the snapshot was created in key.offset */
784 key.offset = trans->transid;
785 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
787 old = btrfs_lock_root_node(root);
788 btrfs_cow_block(trans, root, old, NULL, 0, &old);
789 btrfs_set_lock_blocking(old);
791 btrfs_copy_root(trans, root, old, &tmp, objectid);
792 btrfs_tree_unlock(old);
793 free_extent_buffer(old);
795 btrfs_set_root_node(new_root_item, tmp);
796 ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
798 btrfs_tree_unlock(tmp);
799 free_extent_buffer(tmp);
803 key.offset = (u64)-1;
804 memcpy(&pending->root_key, &key, sizeof(key));
806 kfree(new_root_item);
810 static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
811 struct btrfs_pending_snapshot *pending)
816 struct btrfs_trans_handle *trans;
817 struct inode *parent_inode;
818 struct btrfs_root *parent_root;
820 parent_inode = pending->dentry->d_parent->d_inode;
821 parent_root = BTRFS_I(parent_inode)->root;
822 trans = btrfs_join_transaction(parent_root, 1);
825 * insert the directory item
827 namelen = strlen(pending->name);
828 ret = btrfs_set_inode_index(parent_inode, &index);
829 ret = btrfs_insert_dir_item(trans, parent_root,
830 pending->name, namelen,
832 &pending->root_key, BTRFS_FT_DIR, index);
837 btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
838 ret = btrfs_update_inode(trans, parent_root, parent_inode);
841 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
842 pending->root_key.objectid,
843 parent_root->root_key.objectid,
844 parent_inode->i_ino, index, pending->name,
850 btrfs_end_transaction(trans, fs_info->fs_root);
855 * create all the snapshots we've scheduled for creation
857 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
858 struct btrfs_fs_info *fs_info)
860 struct btrfs_pending_snapshot *pending;
861 struct list_head *head = &trans->transaction->pending_snapshots;
864 list_for_each_entry(pending, head, list) {
865 ret = create_pending_snapshot(trans, fs_info, pending);
871 static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
872 struct btrfs_fs_info *fs_info)
874 struct btrfs_pending_snapshot *pending;
875 struct list_head *head = &trans->transaction->pending_snapshots;
878 while (!list_empty(head)) {
879 pending = list_entry(head->next,
880 struct btrfs_pending_snapshot, list);
881 ret = finish_pending_snapshot(fs_info, pending);
883 list_del(&pending->list);
884 kfree(pending->name);
890 static void update_super_roots(struct btrfs_root *root)
892 struct btrfs_root_item *root_item;
893 struct btrfs_super_block *super;
895 super = &root->fs_info->super_copy;
897 root_item = &root->fs_info->chunk_root->root_item;
898 super->chunk_root = root_item->bytenr;
899 super->chunk_root_generation = root_item->generation;
900 super->chunk_root_level = root_item->level;
902 root_item = &root->fs_info->tree_root->root_item;
903 super->root = root_item->bytenr;
904 super->generation = root_item->generation;
905 super->root_level = root_item->level;
908 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
911 spin_lock(&info->new_trans_lock);
912 if (info->running_transaction)
913 ret = info->running_transaction->in_commit;
914 spin_unlock(&info->new_trans_lock);
918 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
919 struct btrfs_root *root)
921 unsigned long joined = 0;
922 unsigned long timeout = 1;
923 struct btrfs_transaction *cur_trans;
924 struct btrfs_transaction *prev_trans = NULL;
928 unsigned long now = get_seconds();
929 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
931 btrfs_run_ordered_operations(root, 0);
933 /* make a pass through all the delayed refs we have so far
934 * any runnings procs may add more while we are here
936 ret = btrfs_run_delayed_refs(trans, root, 0);
939 cur_trans = trans->transaction;
941 * set the flushing flag so procs in this transaction have to
942 * start sending their work down.
944 cur_trans->delayed_refs.flushing = 1;
946 ret = btrfs_run_delayed_refs(trans, root, 0);
949 mutex_lock(&root->fs_info->trans_mutex);
950 if (cur_trans->in_commit) {
951 cur_trans->use_count++;
952 mutex_unlock(&root->fs_info->trans_mutex);
953 btrfs_end_transaction(trans, root);
955 ret = wait_for_commit(root, cur_trans);
958 mutex_lock(&root->fs_info->trans_mutex);
959 put_transaction(cur_trans);
960 mutex_unlock(&root->fs_info->trans_mutex);
965 trans->transaction->in_commit = 1;
966 trans->transaction->blocked = 1;
967 if (cur_trans->list.prev != &root->fs_info->trans_list) {
968 prev_trans = list_entry(cur_trans->list.prev,
969 struct btrfs_transaction, list);
970 if (!prev_trans->commit_done) {
971 prev_trans->use_count++;
972 mutex_unlock(&root->fs_info->trans_mutex);
974 wait_for_commit(root, prev_trans);
976 mutex_lock(&root->fs_info->trans_mutex);
977 put_transaction(prev_trans);
981 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
985 int snap_pending = 0;
986 joined = cur_trans->num_joined;
987 if (!list_empty(&trans->transaction->pending_snapshots))
990 WARN_ON(cur_trans != trans->transaction);
991 prepare_to_wait(&cur_trans->writer_wait, &wait,
992 TASK_UNINTERRUPTIBLE);
994 if (cur_trans->num_writers > 1)
995 timeout = MAX_SCHEDULE_TIMEOUT;
996 else if (should_grow)
999 mutex_unlock(&root->fs_info->trans_mutex);
1001 if (flush_on_commit || snap_pending) {
1002 btrfs_start_delalloc_inodes(root, 1);
1003 ret = btrfs_wait_ordered_extents(root, 0, 1);
1008 * rename don't use btrfs_join_transaction, so, once we
1009 * set the transaction to blocked above, we aren't going
1010 * to get any new ordered operations. We can safely run
1011 * it here and no for sure that nothing new will be added
1014 btrfs_run_ordered_operations(root, 1);
1017 if (cur_trans->num_writers > 1 || should_grow)
1018 schedule_timeout(timeout);
1020 mutex_lock(&root->fs_info->trans_mutex);
1021 finish_wait(&cur_trans->writer_wait, &wait);
1022 } while (cur_trans->num_writers > 1 ||
1023 (should_grow && cur_trans->num_joined != joined));
1025 ret = create_pending_snapshots(trans, root->fs_info);
1028 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1031 WARN_ON(cur_trans != trans->transaction);
1033 /* btrfs_commit_tree_roots is responsible for getting the
1034 * various roots consistent with each other. Every pointer
1035 * in the tree of tree roots has to point to the most up to date
1036 * root for every subvolume and other tree. So, we have to keep
1037 * the tree logging code from jumping in and changing any
1040 * At this point in the commit, there can't be any tree-log
1041 * writers, but a little lower down we drop the trans mutex
1042 * and let new people in. By holding the tree_log_mutex
1043 * from now until after the super is written, we avoid races
1044 * with the tree-log code.
1046 mutex_lock(&root->fs_info->tree_log_mutex);
1048 ret = commit_fs_roots(trans, root);
1051 /* commit_fs_roots gets rid of all the tree log roots, it is now
1052 * safe to free the root of tree log roots
1054 btrfs_free_log_root_tree(trans, root->fs_info);
1056 ret = commit_cowonly_roots(trans, root);
1059 btrfs_prepare_extent_commit(trans, root);
1061 cur_trans = root->fs_info->running_transaction;
1062 spin_lock(&root->fs_info->new_trans_lock);
1063 root->fs_info->running_transaction = NULL;
1064 spin_unlock(&root->fs_info->new_trans_lock);
1066 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1067 root->fs_info->tree_root->node);
1068 switch_commit_root(root->fs_info->tree_root);
1070 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1071 root->fs_info->chunk_root->node);
1072 switch_commit_root(root->fs_info->chunk_root);
1074 update_super_roots(root);
1076 if (!root->fs_info->log_root_recovering) {
1077 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1078 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1081 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1082 sizeof(root->fs_info->super_copy));
1084 trans->transaction->blocked = 0;
1086 wake_up(&root->fs_info->transaction_wait);
1088 mutex_unlock(&root->fs_info->trans_mutex);
1089 ret = btrfs_write_and_wait_transaction(trans, root);
1091 write_ctree_super(trans, root, 0);
1094 * the super is written, we can safely allow the tree-loggers
1095 * to go about their business
1097 mutex_unlock(&root->fs_info->tree_log_mutex);
1099 btrfs_finish_extent_commit(trans, root);
1101 /* do the directory inserts of any pending snapshot creations */
1102 finish_pending_snapshots(trans, root->fs_info);
1104 mutex_lock(&root->fs_info->trans_mutex);
1106 cur_trans->commit_done = 1;
1108 root->fs_info->last_trans_committed = cur_trans->transid;
1110 wake_up(&cur_trans->commit_wait);
1112 put_transaction(cur_trans);
1113 put_transaction(cur_trans);
1115 mutex_unlock(&root->fs_info->trans_mutex);
1117 if (current->journal_info == trans)
1118 current->journal_info = NULL;
1120 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1122 if (current != root->fs_info->transaction_kthread)
1123 btrfs_run_delayed_iputs(root);
1129 * interface function to delete all the snapshots we have scheduled for deletion
1131 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1134 struct btrfs_fs_info *fs_info = root->fs_info;
1136 mutex_lock(&fs_info->trans_mutex);
1137 list_splice_init(&fs_info->dead_roots, &list);
1138 mutex_unlock(&fs_info->trans_mutex);
1140 while (!list_empty(&list)) {
1141 root = list_entry(list.next, struct btrfs_root, root_list);
1142 list_del(&root->root_list);
1144 if (btrfs_header_backref_rev(root->node) <
1145 BTRFS_MIXED_BACKREF_REV)
1146 btrfs_drop_snapshot(root, 0);
1148 btrfs_drop_snapshot(root, 1);