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"
28 #include "ref-cache.h"
31 extern struct kmem_cache *btrfs_trans_handle_cachep;
32 extern struct kmem_cache *btrfs_transaction_cachep;
34 #define BTRFS_ROOT_TRANS_TAG 0
36 static noinline void put_transaction(struct btrfs_transaction *transaction)
38 WARN_ON(transaction->use_count == 0);
39 transaction->use_count--;
40 if (transaction->use_count == 0) {
41 list_del_init(&transaction->list);
42 memset(transaction, 0, sizeof(*transaction));
43 kmem_cache_free(btrfs_transaction_cachep, transaction);
48 * either allocate a new transaction or hop into the existing one
50 static noinline int join_transaction(struct btrfs_root *root)
52 struct btrfs_transaction *cur_trans;
53 cur_trans = root->fs_info->running_transaction;
55 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
58 root->fs_info->generation++;
59 root->fs_info->last_alloc = 0;
60 root->fs_info->last_data_alloc = 0;
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();
71 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
72 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
73 extent_io_tree_init(&cur_trans->dirty_pages,
74 root->fs_info->btree_inode->i_mapping,
76 spin_lock(&root->fs_info->new_trans_lock);
77 root->fs_info->running_transaction = cur_trans;
78 spin_unlock(&root->fs_info->new_trans_lock);
80 cur_trans->num_writers++;
81 cur_trans->num_joined++;
88 * this does all the record keeping required to make sure that a
89 * reference counted root is properly recorded in a given transaction.
90 * This is required to make sure the old root from before we joined the transaction
91 * is deleted when the transaction commits
93 noinline int btrfs_record_root_in_trans(struct btrfs_root *root)
95 struct btrfs_dirty_root *dirty;
96 u64 running_trans_id = root->fs_info->running_transaction->transid;
97 if (root->ref_cows && root->last_trans < running_trans_id) {
98 WARN_ON(root == root->fs_info->extent_root);
99 if (root->root_item.refs != 0) {
100 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
101 (unsigned long)root->root_key.objectid,
102 BTRFS_ROOT_TRANS_TAG);
104 dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
106 dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
107 BUG_ON(!dirty->root);
108 dirty->latest_root = root;
109 INIT_LIST_HEAD(&dirty->list);
111 root->commit_root = btrfs_root_node(root);
113 memcpy(dirty->root, root, sizeof(*root));
114 spin_lock_init(&dirty->root->node_lock);
115 spin_lock_init(&dirty->root->list_lock);
116 mutex_init(&dirty->root->objectid_mutex);
117 mutex_init(&dirty->root->log_mutex);
118 INIT_LIST_HEAD(&dirty->root->dead_list);
119 dirty->root->node = root->commit_root;
120 dirty->root->commit_root = NULL;
122 spin_lock(&root->list_lock);
123 list_add(&dirty->root->dead_list, &root->dead_list);
124 spin_unlock(&root->list_lock);
126 root->dirty_root = dirty;
130 root->last_trans = running_trans_id;
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 btrfs_record_root_in_trans(root);
181 h->transid = root->fs_info->running_transaction->transid;
182 h->transaction = root->fs_info->running_transaction;
183 h->blocks_reserved = num_blocks;
185 h->block_group = NULL;
186 h->alloc_exclude_nr = 0;
187 h->alloc_exclude_start = 0;
188 root->fs_info->running_transaction->use_count++;
189 mutex_unlock(&root->fs_info->trans_mutex);
193 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
196 return start_transaction(root, num_blocks, 1);
198 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
201 return start_transaction(root, num_blocks, 0);
204 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
207 return start_transaction(r, num_blocks, 2);
210 /* wait for a transaction commit to be fully complete */
211 static noinline int wait_for_commit(struct btrfs_root *root,
212 struct btrfs_transaction *commit)
215 mutex_lock(&root->fs_info->trans_mutex);
216 while(!commit->commit_done) {
217 prepare_to_wait(&commit->commit_wait, &wait,
218 TASK_UNINTERRUPTIBLE);
219 if (commit->commit_done)
221 mutex_unlock(&root->fs_info->trans_mutex);
223 mutex_lock(&root->fs_info->trans_mutex);
225 mutex_unlock(&root->fs_info->trans_mutex);
226 finish_wait(&commit->commit_wait, &wait);
231 * rate limit against the drop_snapshot code. This helps to slow down new operations
232 * if the drop_snapshot code isn't able to keep up.
234 static void throttle_on_drops(struct btrfs_root *root)
236 struct btrfs_fs_info *info = root->fs_info;
237 int harder_count = 0;
240 if (atomic_read(&info->throttles)) {
243 thr = atomic_read(&info->throttle_gen);
246 prepare_to_wait(&info->transaction_throttle,
247 &wait, TASK_UNINTERRUPTIBLE);
248 if (!atomic_read(&info->throttles)) {
249 finish_wait(&info->transaction_throttle, &wait);
253 finish_wait(&info->transaction_throttle, &wait);
254 } while (thr == atomic_read(&info->throttle_gen));
257 if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
261 if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
265 if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
271 void btrfs_throttle(struct btrfs_root *root)
273 mutex_lock(&root->fs_info->trans_mutex);
274 if (!root->fs_info->open_ioctl_trans)
275 wait_current_trans(root);
276 mutex_unlock(&root->fs_info->trans_mutex);
278 throttle_on_drops(root);
281 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
282 struct btrfs_root *root, int throttle)
284 struct btrfs_transaction *cur_trans;
285 struct btrfs_fs_info *info = root->fs_info;
287 mutex_lock(&info->trans_mutex);
288 cur_trans = info->running_transaction;
289 WARN_ON(cur_trans != trans->transaction);
290 WARN_ON(cur_trans->num_writers < 1);
291 cur_trans->num_writers--;
293 if (waitqueue_active(&cur_trans->writer_wait))
294 wake_up(&cur_trans->writer_wait);
295 put_transaction(cur_trans);
296 mutex_unlock(&info->trans_mutex);
297 memset(trans, 0, sizeof(*trans));
298 kmem_cache_free(btrfs_trans_handle_cachep, trans);
301 throttle_on_drops(root);
306 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
307 struct btrfs_root *root)
309 return __btrfs_end_transaction(trans, root, 0);
312 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
313 struct btrfs_root *root)
315 return __btrfs_end_transaction(trans, root, 1);
319 * when btree blocks are allocated, they have some corresponding bits set for
320 * them in one of two extent_io trees. This is used to make sure all of
321 * those extents are on disk for transaction or log commit
323 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
324 struct extent_io_tree *dirty_pages)
330 struct inode *btree_inode = root->fs_info->btree_inode;
336 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
340 while(start <= end) {
343 index = start >> PAGE_CACHE_SHIFT;
344 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
345 page = find_get_page(btree_inode->i_mapping, index);
349 btree_lock_page_hook(page);
350 if (!page->mapping) {
352 page_cache_release(page);
356 if (PageWriteback(page)) {
358 wait_on_page_writeback(page);
361 page_cache_release(page);
365 err = write_one_page(page, 0);
368 page_cache_release(page);
372 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
377 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
378 while(start <= end) {
379 index = start >> PAGE_CACHE_SHIFT;
380 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
381 page = find_get_page(btree_inode->i_mapping, index);
384 if (PageDirty(page)) {
385 btree_lock_page_hook(page);
386 wait_on_page_writeback(page);
387 err = write_one_page(page, 0);
391 wait_on_page_writeback(page);
392 page_cache_release(page);
401 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
402 struct btrfs_root *root)
404 if (!trans || !trans->transaction) {
405 struct inode *btree_inode;
406 btree_inode = root->fs_info->btree_inode;
407 return filemap_write_and_wait(btree_inode->i_mapping);
409 return btrfs_write_and_wait_marked_extents(root,
410 &trans->transaction->dirty_pages);
414 * this is used to update the root pointer in the tree of tree roots.
416 * But, in the case of the extent allocation tree, updating the root
417 * pointer may allocate blocks which may change the root of the extent
420 * So, this loops and repeats and makes sure the cowonly root didn't
421 * change while the root pointer was being updated in the metadata.
423 static int update_cowonly_root(struct btrfs_trans_handle *trans,
424 struct btrfs_root *root)
428 struct btrfs_root *tree_root = root->fs_info->tree_root;
430 btrfs_extent_post_op(trans, root);
431 btrfs_write_dirty_block_groups(trans, root);
432 btrfs_extent_post_op(trans, root);
435 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
436 if (old_root_bytenr == root->node->start)
438 btrfs_set_root_bytenr(&root->root_item,
440 btrfs_set_root_level(&root->root_item,
441 btrfs_header_level(root->node));
442 btrfs_set_root_generation(&root->root_item, trans->transid);
444 btrfs_extent_post_op(trans, root);
446 ret = btrfs_update_root(trans, tree_root,
450 btrfs_write_dirty_block_groups(trans, root);
451 btrfs_extent_post_op(trans, root);
457 * update all the cowonly tree roots on disk
459 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
460 struct btrfs_root *root)
462 struct btrfs_fs_info *fs_info = root->fs_info;
463 struct list_head *next;
464 struct extent_buffer *eb;
466 btrfs_extent_post_op(trans, fs_info->tree_root);
468 eb = btrfs_lock_root_node(fs_info->tree_root);
469 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb, 0);
470 btrfs_tree_unlock(eb);
471 free_extent_buffer(eb);
473 btrfs_extent_post_op(trans, fs_info->tree_root);
475 while(!list_empty(&fs_info->dirty_cowonly_roots)) {
476 next = fs_info->dirty_cowonly_roots.next;
478 root = list_entry(next, struct btrfs_root, dirty_list);
480 update_cowonly_root(trans, root);
486 * dead roots are old snapshots that need to be deleted. This allocates
487 * a dirty root struct and adds it into the list of dead roots that need to
490 int btrfs_add_dead_root(struct btrfs_root *root, struct btrfs_root *latest)
492 struct btrfs_dirty_root *dirty;
494 dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
498 dirty->latest_root = latest;
500 mutex_lock(&root->fs_info->trans_mutex);
501 list_add(&dirty->list, &latest->fs_info->dead_roots);
502 mutex_unlock(&root->fs_info->trans_mutex);
507 * at transaction commit time we need to schedule the old roots for
508 * deletion via btrfs_drop_snapshot. This runs through all the
509 * reference counted roots that were modified in the current
510 * transaction and puts them into the drop list
512 static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
513 struct radix_tree_root *radix,
514 struct list_head *list)
516 struct btrfs_dirty_root *dirty;
517 struct btrfs_root *gang[8];
518 struct btrfs_root *root;
525 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
527 BTRFS_ROOT_TRANS_TAG);
530 for (i = 0; i < ret; i++) {
532 radix_tree_tag_clear(radix,
533 (unsigned long)root->root_key.objectid,
534 BTRFS_ROOT_TRANS_TAG);
536 BUG_ON(!root->ref_tree);
537 dirty = root->dirty_root;
539 btrfs_free_log(trans, root);
540 btrfs_free_reloc_root(trans, root);
542 if (root->commit_root == root->node) {
543 WARN_ON(root->node->start !=
544 btrfs_root_bytenr(&root->root_item));
546 free_extent_buffer(root->commit_root);
547 root->commit_root = NULL;
548 root->dirty_root = NULL;
550 spin_lock(&root->list_lock);
551 list_del_init(&dirty->root->dead_list);
552 spin_unlock(&root->list_lock);
557 /* make sure to update the root on disk
558 * so we get any updates to the block used
561 err = btrfs_update_root(trans,
562 root->fs_info->tree_root,
568 memset(&root->root_item.drop_progress, 0,
569 sizeof(struct btrfs_disk_key));
570 root->root_item.drop_level = 0;
571 root->commit_root = NULL;
572 root->dirty_root = NULL;
573 root->root_key.offset = root->fs_info->generation;
574 btrfs_set_root_bytenr(&root->root_item,
576 btrfs_set_root_level(&root->root_item,
577 btrfs_header_level(root->node));
578 btrfs_set_root_generation(&root->root_item,
579 root->root_key.offset);
581 err = btrfs_insert_root(trans, root->fs_info->tree_root,
587 refs = btrfs_root_refs(&dirty->root->root_item);
588 btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
589 err = btrfs_update_root(trans, root->fs_info->tree_root,
590 &dirty->root->root_key,
591 &dirty->root->root_item);
595 list_add(&dirty->list, list);
598 free_extent_buffer(dirty->root->node);
608 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
609 * otherwise every leaf in the btree is read and defragged.
611 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
613 struct btrfs_fs_info *info = root->fs_info;
615 struct btrfs_trans_handle *trans;
619 if (root->defrag_running)
621 trans = btrfs_start_transaction(root, 1);
623 root->defrag_running = 1;
624 ret = btrfs_defrag_leaves(trans, root, cacheonly);
625 nr = trans->blocks_used;
626 btrfs_end_transaction(trans, root);
627 btrfs_btree_balance_dirty(info->tree_root, nr);
630 trans = btrfs_start_transaction(root, 1);
631 if (root->fs_info->closing || ret != -EAGAIN)
634 root->defrag_running = 0;
636 btrfs_end_transaction(trans, root);
641 * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
644 static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
645 struct list_head *list)
647 struct btrfs_dirty_root *dirty;
648 struct btrfs_trans_handle *trans;
656 while(!list_empty(list)) {
657 struct btrfs_root *root;
659 dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
660 list_del_init(&dirty->list);
662 num_bytes = btrfs_root_used(&dirty->root->root_item);
663 root = dirty->latest_root;
664 atomic_inc(&root->fs_info->throttles);
667 trans = btrfs_start_transaction(tree_root, 1);
668 mutex_lock(&root->fs_info->drop_mutex);
669 ret = btrfs_drop_snapshot(trans, dirty->root);
670 if (ret != -EAGAIN) {
673 mutex_unlock(&root->fs_info->drop_mutex);
675 err = btrfs_update_root(trans,
677 &dirty->root->root_key,
678 &dirty->root->root_item);
681 nr = trans->blocks_used;
682 ret = btrfs_end_transaction(trans, tree_root);
685 btrfs_btree_balance_dirty(tree_root, nr);
689 atomic_dec(&root->fs_info->throttles);
690 wake_up(&root->fs_info->transaction_throttle);
692 num_bytes -= btrfs_root_used(&dirty->root->root_item);
693 bytes_used = btrfs_root_used(&root->root_item);
695 btrfs_record_root_in_trans(root);
696 btrfs_set_root_used(&root->root_item,
697 bytes_used - num_bytes);
700 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
705 mutex_unlock(&root->fs_info->drop_mutex);
707 spin_lock(&root->list_lock);
708 list_del_init(&dirty->root->dead_list);
709 if (!list_empty(&root->dead_list)) {
710 struct btrfs_root *oldest;
711 oldest = list_entry(root->dead_list.prev,
712 struct btrfs_root, dead_list);
713 max_useless = oldest->root_key.offset - 1;
715 max_useless = root->root_key.offset - 1;
717 spin_unlock(&root->list_lock);
719 nr = trans->blocks_used;
720 ret = btrfs_end_transaction(trans, tree_root);
723 ret = btrfs_remove_leaf_refs(root, max_useless, 0);
726 free_extent_buffer(dirty->root->node);
730 btrfs_btree_balance_dirty(tree_root, nr);
737 * new snapshots need to be created at a very specific time in the
738 * transaction commit. This does the actual creation
740 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
741 struct btrfs_fs_info *fs_info,
742 struct btrfs_pending_snapshot *pending)
744 struct btrfs_key key;
745 struct btrfs_root_item *new_root_item;
746 struct btrfs_root *tree_root = fs_info->tree_root;
747 struct btrfs_root *root = pending->root;
748 struct extent_buffer *tmp;
749 struct extent_buffer *old;
753 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
754 if (!new_root_item) {
758 ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
762 btrfs_record_root_in_trans(root);
763 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
764 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
766 key.objectid = objectid;
767 key.offset = trans->transid;
768 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
770 old = btrfs_lock_root_node(root);
771 btrfs_cow_block(trans, root, old, NULL, 0, &old, 0);
773 btrfs_copy_root(trans, root, old, &tmp, objectid);
774 btrfs_tree_unlock(old);
775 free_extent_buffer(old);
777 btrfs_set_root_bytenr(new_root_item, tmp->start);
778 btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
779 btrfs_set_root_generation(new_root_item, trans->transid);
780 ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
782 btrfs_tree_unlock(tmp);
783 free_extent_buffer(tmp);
787 key.offset = (u64)-1;
788 memcpy(&pending->root_key, &key, sizeof(key));
790 kfree(new_root_item);
794 static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
795 struct btrfs_pending_snapshot *pending)
800 struct btrfs_trans_handle *trans;
801 struct inode *parent_inode;
803 struct btrfs_root *parent_root;
805 parent_inode = pending->dentry->d_parent->d_inode;
806 parent_root = BTRFS_I(parent_inode)->root;
807 trans = btrfs_start_transaction(parent_root, 1);
810 * insert the directory item
812 namelen = strlen(pending->name);
813 ret = btrfs_set_inode_index(parent_inode, &index);
814 ret = btrfs_insert_dir_item(trans, parent_root,
815 pending->name, namelen,
817 &pending->root_key, BTRFS_FT_DIR, index);
822 /* add the backref first */
823 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
824 pending->root_key.objectid,
825 BTRFS_ROOT_BACKREF_KEY,
826 parent_root->root_key.objectid,
827 parent_inode->i_ino, index, pending->name,
832 /* now add the forward ref */
833 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
834 parent_root->root_key.objectid,
836 pending->root_key.objectid,
837 parent_inode->i_ino, index, pending->name,
840 inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
841 d_instantiate(pending->dentry, inode);
843 btrfs_end_transaction(trans, fs_info->fs_root);
848 * create all the snapshots we've scheduled for creation
850 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
851 struct btrfs_fs_info *fs_info)
853 struct btrfs_pending_snapshot *pending;
854 struct list_head *head = &trans->transaction->pending_snapshots;
855 struct list_head *cur;
858 list_for_each(cur, head) {
859 pending = list_entry(cur, struct btrfs_pending_snapshot, list);
860 ret = create_pending_snapshot(trans, fs_info, pending);
866 static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
867 struct btrfs_fs_info *fs_info)
869 struct btrfs_pending_snapshot *pending;
870 struct list_head *head = &trans->transaction->pending_snapshots;
873 while(!list_empty(head)) {
874 pending = list_entry(head->next,
875 struct btrfs_pending_snapshot, list);
876 ret = finish_pending_snapshot(fs_info, pending);
878 list_del(&pending->list);
879 kfree(pending->name);
885 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
886 struct btrfs_root *root)
888 unsigned long joined = 0;
889 unsigned long timeout = 1;
890 struct btrfs_transaction *cur_trans;
891 struct btrfs_transaction *prev_trans = NULL;
892 struct btrfs_root *chunk_root = root->fs_info->chunk_root;
893 struct list_head dirty_fs_roots;
894 struct extent_io_tree *pinned_copy;
898 INIT_LIST_HEAD(&dirty_fs_roots);
899 mutex_lock(&root->fs_info->trans_mutex);
900 if (trans->transaction->in_commit) {
901 cur_trans = trans->transaction;
902 trans->transaction->use_count++;
903 mutex_unlock(&root->fs_info->trans_mutex);
904 btrfs_end_transaction(trans, root);
906 ret = wait_for_commit(root, cur_trans);
909 mutex_lock(&root->fs_info->trans_mutex);
910 put_transaction(cur_trans);
911 mutex_unlock(&root->fs_info->trans_mutex);
916 pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
920 extent_io_tree_init(pinned_copy,
921 root->fs_info->btree_inode->i_mapping, GFP_NOFS);
923 trans->transaction->in_commit = 1;
924 trans->transaction->blocked = 1;
925 cur_trans = trans->transaction;
926 if (cur_trans->list.prev != &root->fs_info->trans_list) {
927 prev_trans = list_entry(cur_trans->list.prev,
928 struct btrfs_transaction, list);
929 if (!prev_trans->commit_done) {
930 prev_trans->use_count++;
931 mutex_unlock(&root->fs_info->trans_mutex);
933 wait_for_commit(root, prev_trans);
935 mutex_lock(&root->fs_info->trans_mutex);
936 put_transaction(prev_trans);
941 int snap_pending = 0;
942 joined = cur_trans->num_joined;
943 if (!list_empty(&trans->transaction->pending_snapshots))
946 WARN_ON(cur_trans != trans->transaction);
947 prepare_to_wait(&cur_trans->writer_wait, &wait,
948 TASK_UNINTERRUPTIBLE);
950 if (cur_trans->num_writers > 1)
951 timeout = MAX_SCHEDULE_TIMEOUT;
955 mutex_unlock(&root->fs_info->trans_mutex);
958 ret = btrfs_wait_ordered_extents(root, 1);
962 schedule_timeout(timeout);
964 mutex_lock(&root->fs_info->trans_mutex);
965 finish_wait(&cur_trans->writer_wait, &wait);
966 } while (cur_trans->num_writers > 1 ||
967 (cur_trans->num_joined != joined));
969 ret = create_pending_snapshots(trans, root->fs_info);
972 WARN_ON(cur_trans != trans->transaction);
974 /* btrfs_commit_tree_roots is responsible for getting the
975 * various roots consistent with each other. Every pointer
976 * in the tree of tree roots has to point to the most up to date
977 * root for every subvolume and other tree. So, we have to keep
978 * the tree logging code from jumping in and changing any
981 * At this point in the commit, there can't be any tree-log
982 * writers, but a little lower down we drop the trans mutex
983 * and let new people in. By holding the tree_log_mutex
984 * from now until after the super is written, we avoid races
985 * with the tree-log code.
987 mutex_lock(&root->fs_info->tree_log_mutex);
989 * keep tree reloc code from adding new reloc trees
991 mutex_lock(&root->fs_info->tree_reloc_mutex);
994 ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
998 /* add_dirty_roots gets rid of all the tree log roots, it is now
999 * safe to free the root of tree log roots
1001 btrfs_free_log_root_tree(trans, root->fs_info);
1003 ret = btrfs_commit_tree_roots(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);
1010 btrfs_set_super_generation(&root->fs_info->super_copy,
1011 cur_trans->transid);
1012 btrfs_set_super_root(&root->fs_info->super_copy,
1013 root->fs_info->tree_root->node->start);
1014 btrfs_set_super_root_level(&root->fs_info->super_copy,
1015 btrfs_header_level(root->fs_info->tree_root->node));
1017 btrfs_set_super_chunk_root(&root->fs_info->super_copy,
1018 chunk_root->node->start);
1019 btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
1020 btrfs_header_level(chunk_root->node));
1021 btrfs_set_super_chunk_root_generation(&root->fs_info->super_copy,
1022 btrfs_header_generation(chunk_root->node));
1024 if (!root->fs_info->log_root_recovering) {
1025 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1026 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1029 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1030 sizeof(root->fs_info->super_copy));
1032 btrfs_copy_pinned(root, pinned_copy);
1034 trans->transaction->blocked = 0;
1035 wake_up(&root->fs_info->transaction_throttle);
1036 wake_up(&root->fs_info->transaction_wait);
1038 mutex_unlock(&root->fs_info->trans_mutex);
1039 ret = btrfs_write_and_wait_transaction(trans, root);
1041 write_ctree_super(trans, root);
1044 * the super is written, we can safely allow the tree-loggers
1045 * to go about their business
1047 mutex_unlock(&root->fs_info->tree_log_mutex);
1049 btrfs_finish_extent_commit(trans, root, pinned_copy);
1052 btrfs_drop_dead_reloc_roots(root);
1053 mutex_unlock(&root->fs_info->tree_reloc_mutex);
1055 /* do the directory inserts of any pending snapshot creations */
1056 finish_pending_snapshots(trans, root->fs_info);
1058 mutex_lock(&root->fs_info->trans_mutex);
1060 cur_trans->commit_done = 1;
1061 root->fs_info->last_trans_committed = cur_trans->transid;
1062 wake_up(&cur_trans->commit_wait);
1064 put_transaction(cur_trans);
1065 put_transaction(cur_trans);
1067 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
1068 if (root->fs_info->closing)
1069 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
1071 mutex_unlock(&root->fs_info->trans_mutex);
1073 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1075 if (root->fs_info->closing) {
1076 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
1082 * interface function to delete all the snapshots we have scheduled for deletion
1084 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1086 struct list_head dirty_roots;
1087 INIT_LIST_HEAD(&dirty_roots);
1089 mutex_lock(&root->fs_info->trans_mutex);
1090 list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
1091 mutex_unlock(&root->fs_info->trans_mutex);
1093 if (!list_empty(&dirty_roots)) {
1094 drop_dirty_roots(root, &dirty_roots);