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)
153 mutex_unlock(&root->fs_info->trans_mutex);
155 mutex_lock(&root->fs_info->trans_mutex);
157 finish_wait(&root->fs_info->transaction_wait, &wait);
158 put_transaction(cur_trans);
162 enum btrfs_trans_type {
168 static int may_wait_transaction(struct btrfs_root *root, int type)
170 if (!root->fs_info->log_root_recovering &&
171 ((type == TRANS_START && !root->fs_info->open_ioctl_trans) ||
172 type == TRANS_USERSPACE))
177 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
178 u64 num_items, int type)
180 struct btrfs_trans_handle *h;
181 struct btrfs_transaction *cur_trans;
185 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
187 return ERR_PTR(-ENOMEM);
189 mutex_lock(&root->fs_info->trans_mutex);
190 if (may_wait_transaction(root, type))
191 wait_current_trans(root);
193 ret = join_transaction(root);
196 cur_trans = root->fs_info->running_transaction;
197 cur_trans->use_count++;
198 mutex_unlock(&root->fs_info->trans_mutex);
200 h->transid = cur_trans->transid;
201 h->transaction = cur_trans;
204 h->bytes_reserved = 0;
205 h->delayed_ref_updates = 0;
209 if (cur_trans->blocked && may_wait_transaction(root, type)) {
210 btrfs_commit_transaction(h, root);
215 ret = btrfs_trans_reserve_metadata(h, root, num_items,
217 if (ret == -EAGAIN) {
218 btrfs_commit_transaction(h, root);
222 btrfs_end_transaction(h, root);
227 mutex_lock(&root->fs_info->trans_mutex);
228 record_root_in_trans(h, root);
229 mutex_unlock(&root->fs_info->trans_mutex);
231 if (!current->journal_info && type != TRANS_USERSPACE)
232 current->journal_info = h;
236 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
239 return start_transaction(root, num_items, TRANS_START);
241 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
244 return start_transaction(root, 0, TRANS_JOIN);
247 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
250 return start_transaction(r, 0, TRANS_USERSPACE);
253 /* wait for a transaction commit to be fully complete */
254 static noinline int wait_for_commit(struct btrfs_root *root,
255 struct btrfs_transaction *commit)
258 mutex_lock(&root->fs_info->trans_mutex);
259 while (!commit->commit_done) {
260 prepare_to_wait(&commit->commit_wait, &wait,
261 TASK_UNINTERRUPTIBLE);
262 if (commit->commit_done)
264 mutex_unlock(&root->fs_info->trans_mutex);
266 mutex_lock(&root->fs_info->trans_mutex);
268 mutex_unlock(&root->fs_info->trans_mutex);
269 finish_wait(&commit->commit_wait, &wait);
275 * rate limit against the drop_snapshot code. This helps to slow down new
276 * operations if the drop_snapshot code isn't able to keep up.
278 static void throttle_on_drops(struct btrfs_root *root)
280 struct btrfs_fs_info *info = root->fs_info;
281 int harder_count = 0;
284 if (atomic_read(&info->throttles)) {
287 thr = atomic_read(&info->throttle_gen);
290 prepare_to_wait(&info->transaction_throttle,
291 &wait, TASK_UNINTERRUPTIBLE);
292 if (!atomic_read(&info->throttles)) {
293 finish_wait(&info->transaction_throttle, &wait);
297 finish_wait(&info->transaction_throttle, &wait);
298 } while (thr == atomic_read(&info->throttle_gen));
301 if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
305 if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
309 if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
316 void btrfs_throttle(struct btrfs_root *root)
318 mutex_lock(&root->fs_info->trans_mutex);
319 if (!root->fs_info->open_ioctl_trans)
320 wait_current_trans(root);
321 mutex_unlock(&root->fs_info->trans_mutex);
324 static int should_end_transaction(struct btrfs_trans_handle *trans,
325 struct btrfs_root *root)
328 ret = btrfs_block_rsv_check(trans, root,
329 &root->fs_info->global_block_rsv, 0, 5);
333 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
334 struct btrfs_root *root)
336 struct btrfs_transaction *cur_trans = trans->transaction;
339 if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
342 updates = trans->delayed_ref_updates;
343 trans->delayed_ref_updates = 0;
345 btrfs_run_delayed_refs(trans, root, updates);
347 return should_end_transaction(trans, root);
350 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
351 struct btrfs_root *root, int throttle)
353 struct btrfs_transaction *cur_trans = trans->transaction;
354 struct btrfs_fs_info *info = root->fs_info;
358 unsigned long cur = trans->delayed_ref_updates;
359 trans->delayed_ref_updates = 0;
361 trans->transaction->delayed_refs.num_heads_ready > 64) {
362 trans->delayed_ref_updates = 0;
365 * do a full flush if the transaction is trying
368 if (trans->transaction->delayed_refs.flushing)
370 btrfs_run_delayed_refs(trans, root, cur);
377 btrfs_trans_release_metadata(trans, root);
379 if (!root->fs_info->open_ioctl_trans &&
380 should_end_transaction(trans, root))
381 trans->transaction->blocked = 1;
383 if (cur_trans->blocked && !cur_trans->in_commit) {
385 return btrfs_commit_transaction(trans, root);
387 wake_up_process(info->transaction_kthread);
390 mutex_lock(&info->trans_mutex);
391 WARN_ON(cur_trans != info->running_transaction);
392 WARN_ON(cur_trans->num_writers < 1);
393 cur_trans->num_writers--;
395 if (waitqueue_active(&cur_trans->writer_wait))
396 wake_up(&cur_trans->writer_wait);
397 put_transaction(cur_trans);
398 mutex_unlock(&info->trans_mutex);
400 if (current->journal_info == trans)
401 current->journal_info = NULL;
402 memset(trans, 0, sizeof(*trans));
403 kmem_cache_free(btrfs_trans_handle_cachep, trans);
406 btrfs_run_delayed_iputs(root);
411 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
412 struct btrfs_root *root)
414 return __btrfs_end_transaction(trans, root, 0);
417 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
418 struct btrfs_root *root)
420 return __btrfs_end_transaction(trans, root, 1);
424 * when btree blocks are allocated, they have some corresponding bits set for
425 * them in one of two extent_io trees. This is used to make sure all of
426 * those extents are sent to disk but does not wait on them
428 int btrfs_write_marked_extents(struct btrfs_root *root,
429 struct extent_io_tree *dirty_pages, int mark)
435 struct inode *btree_inode = root->fs_info->btree_inode;
441 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
445 while (start <= end) {
448 index = start >> PAGE_CACHE_SHIFT;
449 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
450 page = find_get_page(btree_inode->i_mapping, index);
454 btree_lock_page_hook(page);
455 if (!page->mapping) {
457 page_cache_release(page);
461 if (PageWriteback(page)) {
463 wait_on_page_writeback(page);
466 page_cache_release(page);
470 err = write_one_page(page, 0);
473 page_cache_release(page);
482 * when btree blocks are allocated, they have some corresponding bits set for
483 * them in one of two extent_io trees. This is used to make sure all of
484 * those extents are on disk for transaction or log commit. We wait
485 * on all the pages and clear them from the dirty pages state tree
487 int btrfs_wait_marked_extents(struct btrfs_root *root,
488 struct extent_io_tree *dirty_pages, int mark)
494 struct inode *btree_inode = root->fs_info->btree_inode;
500 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
505 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
506 while (start <= end) {
507 index = start >> PAGE_CACHE_SHIFT;
508 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
509 page = find_get_page(btree_inode->i_mapping, index);
512 if (PageDirty(page)) {
513 btree_lock_page_hook(page);
514 wait_on_page_writeback(page);
515 err = write_one_page(page, 0);
519 wait_on_page_writeback(page);
520 page_cache_release(page);
530 * when btree blocks are allocated, they have some corresponding bits set for
531 * them in one of two extent_io trees. This is used to make sure all of
532 * those extents are on disk for transaction or log commit
534 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
535 struct extent_io_tree *dirty_pages, int mark)
540 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
541 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
545 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
546 struct btrfs_root *root)
548 if (!trans || !trans->transaction) {
549 struct inode *btree_inode;
550 btree_inode = root->fs_info->btree_inode;
551 return filemap_write_and_wait(btree_inode->i_mapping);
553 return btrfs_write_and_wait_marked_extents(root,
554 &trans->transaction->dirty_pages,
559 * this is used to update the root pointer in the tree of tree roots.
561 * But, in the case of the extent allocation tree, updating the root
562 * pointer may allocate blocks which may change the root of the extent
565 * So, this loops and repeats and makes sure the cowonly root didn't
566 * change while the root pointer was being updated in the metadata.
568 static int update_cowonly_root(struct btrfs_trans_handle *trans,
569 struct btrfs_root *root)
574 struct btrfs_root *tree_root = root->fs_info->tree_root;
576 old_root_used = btrfs_root_used(&root->root_item);
577 btrfs_write_dirty_block_groups(trans, root);
580 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
581 if (old_root_bytenr == root->node->start &&
582 old_root_used == btrfs_root_used(&root->root_item))
585 btrfs_set_root_node(&root->root_item, root->node);
586 ret = btrfs_update_root(trans, tree_root,
591 old_root_used = btrfs_root_used(&root->root_item);
592 ret = btrfs_write_dirty_block_groups(trans, root);
596 if (root != root->fs_info->extent_root)
597 switch_commit_root(root);
603 * update all the cowonly tree roots on disk
605 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
606 struct btrfs_root *root)
608 struct btrfs_fs_info *fs_info = root->fs_info;
609 struct list_head *next;
610 struct extent_buffer *eb;
613 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
616 eb = btrfs_lock_root_node(fs_info->tree_root);
617 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
618 btrfs_tree_unlock(eb);
619 free_extent_buffer(eb);
621 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
624 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
625 next = fs_info->dirty_cowonly_roots.next;
627 root = list_entry(next, struct btrfs_root, dirty_list);
629 update_cowonly_root(trans, root);
632 down_write(&fs_info->extent_commit_sem);
633 switch_commit_root(fs_info->extent_root);
634 up_write(&fs_info->extent_commit_sem);
640 * dead roots are old snapshots that need to be deleted. This allocates
641 * a dirty root struct and adds it into the list of dead roots that need to
644 int btrfs_add_dead_root(struct btrfs_root *root)
646 mutex_lock(&root->fs_info->trans_mutex);
647 list_add(&root->root_list, &root->fs_info->dead_roots);
648 mutex_unlock(&root->fs_info->trans_mutex);
653 * update all the cowonly tree roots on disk
655 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
656 struct btrfs_root *root)
658 struct btrfs_root *gang[8];
659 struct btrfs_fs_info *fs_info = root->fs_info;
665 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
668 BTRFS_ROOT_TRANS_TAG);
671 for (i = 0; i < ret; i++) {
673 radix_tree_tag_clear(&fs_info->fs_roots_radix,
674 (unsigned long)root->root_key.objectid,
675 BTRFS_ROOT_TRANS_TAG);
677 btrfs_free_log(trans, root);
678 btrfs_update_reloc_root(trans, root);
679 btrfs_orphan_commit_root(trans, root);
681 if (root->commit_root != root->node) {
682 switch_commit_root(root);
683 btrfs_set_root_node(&root->root_item,
687 err = btrfs_update_root(trans, fs_info->tree_root,
698 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
699 * otherwise every leaf in the btree is read and defragged.
701 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
703 struct btrfs_fs_info *info = root->fs_info;
704 struct btrfs_trans_handle *trans;
708 if (xchg(&root->defrag_running, 1))
712 trans = btrfs_start_transaction(root, 0);
714 return PTR_ERR(trans);
716 ret = btrfs_defrag_leaves(trans, root, cacheonly);
718 nr = trans->blocks_used;
719 btrfs_end_transaction(trans, root);
720 btrfs_btree_balance_dirty(info->tree_root, nr);
723 if (root->fs_info->closing || ret != -EAGAIN)
726 root->defrag_running = 0;
732 * when dropping snapshots, we generate a ton of delayed refs, and it makes
733 * sense not to join the transaction while it is trying to flush the current
734 * queue of delayed refs out.
736 * This is used by the drop snapshot code only
738 static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
742 mutex_lock(&info->trans_mutex);
743 while (info->running_transaction &&
744 info->running_transaction->delayed_refs.flushing) {
745 prepare_to_wait(&info->transaction_wait, &wait,
746 TASK_UNINTERRUPTIBLE);
747 mutex_unlock(&info->trans_mutex);
751 mutex_lock(&info->trans_mutex);
752 finish_wait(&info->transaction_wait, &wait);
754 mutex_unlock(&info->trans_mutex);
759 * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
762 int btrfs_drop_dead_root(struct btrfs_root *root)
764 struct btrfs_trans_handle *trans;
765 struct btrfs_root *tree_root = root->fs_info->tree_root;
771 * we don't want to jump in and create a bunch of
772 * delayed refs if the transaction is starting to close
774 wait_transaction_pre_flush(tree_root->fs_info);
775 trans = btrfs_start_transaction(tree_root, 1);
778 * we've joined a transaction, make sure it isn't
781 if (trans->transaction->delayed_refs.flushing) {
782 btrfs_end_transaction(trans, tree_root);
786 ret = btrfs_drop_snapshot(trans, root);
790 ret = btrfs_update_root(trans, tree_root,
796 nr = trans->blocks_used;
797 ret = btrfs_end_transaction(trans, tree_root);
800 btrfs_btree_balance_dirty(tree_root, nr);
805 ret = btrfs_del_root(trans, tree_root, &root->root_key);
808 nr = trans->blocks_used;
809 ret = btrfs_end_transaction(trans, tree_root);
812 free_extent_buffer(root->node);
813 free_extent_buffer(root->commit_root);
816 btrfs_btree_balance_dirty(tree_root, nr);
822 * new snapshots need to be created at a very specific time in the
823 * transaction commit. This does the actual creation
825 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
826 struct btrfs_fs_info *fs_info,
827 struct btrfs_pending_snapshot *pending)
829 struct btrfs_key key;
830 struct btrfs_root_item *new_root_item;
831 struct btrfs_root *tree_root = fs_info->tree_root;
832 struct btrfs_root *root = pending->root;
833 struct btrfs_root *parent_root;
834 struct inode *parent_inode;
835 struct dentry *dentry;
836 struct extent_buffer *tmp;
837 struct extent_buffer *old;
844 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
845 if (!new_root_item) {
846 pending->error = -ENOMEM;
850 ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
852 pending->error = ret;
856 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
857 btrfs_orphan_pre_snapshot(trans, pending, &to_reserve);
859 if (to_reserve > 0) {
860 ret = btrfs_block_rsv_add(trans, root, &pending->block_rsv,
861 to_reserve, &retries);
863 pending->error = ret;
868 key.objectid = objectid;
869 key.offset = (u64)-1;
870 key.type = BTRFS_ROOT_ITEM_KEY;
872 trans->block_rsv = &pending->block_rsv;
874 dentry = pending->dentry;
875 parent_inode = dentry->d_parent->d_inode;
876 parent_root = BTRFS_I(parent_inode)->root;
877 record_root_in_trans(trans, parent_root);
880 * insert the directory item
882 ret = btrfs_set_inode_index(parent_inode, &index);
884 ret = btrfs_insert_dir_item(trans, parent_root,
885 dentry->d_name.name, dentry->d_name.len,
886 parent_inode->i_ino, &key,
887 BTRFS_FT_DIR, index);
890 btrfs_i_size_write(parent_inode, parent_inode->i_size +
891 dentry->d_name.len * 2);
892 ret = btrfs_update_inode(trans, parent_root, parent_inode);
895 record_root_in_trans(trans, root);
896 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
897 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
899 old = btrfs_lock_root_node(root);
900 btrfs_cow_block(trans, root, old, NULL, 0, &old);
901 btrfs_set_lock_blocking(old);
903 btrfs_copy_root(trans, root, old, &tmp, objectid);
904 btrfs_tree_unlock(old);
905 free_extent_buffer(old);
907 btrfs_set_root_node(new_root_item, tmp);
908 /* record when the snapshot was created in key.offset */
909 key.offset = trans->transid;
910 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
911 btrfs_tree_unlock(tmp);
912 free_extent_buffer(tmp);
916 * insert root back/forward references
918 ret = btrfs_add_root_ref(trans, tree_root, objectid,
919 parent_root->root_key.objectid,
920 parent_inode->i_ino, index,
921 dentry->d_name.name, dentry->d_name.len);
924 key.offset = (u64)-1;
925 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
926 BUG_ON(IS_ERR(pending->snap));
928 btrfs_reloc_post_snapshot(trans, pending);
929 btrfs_orphan_post_snapshot(trans, pending);
931 kfree(new_root_item);
932 btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
937 * create all the snapshots we've scheduled for creation
939 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
940 struct btrfs_fs_info *fs_info)
942 struct btrfs_pending_snapshot *pending;
943 struct list_head *head = &trans->transaction->pending_snapshots;
946 list_for_each_entry(pending, head, list) {
947 ret = create_pending_snapshot(trans, fs_info, pending);
953 static void update_super_roots(struct btrfs_root *root)
955 struct btrfs_root_item *root_item;
956 struct btrfs_super_block *super;
958 super = &root->fs_info->super_copy;
960 root_item = &root->fs_info->chunk_root->root_item;
961 super->chunk_root = root_item->bytenr;
962 super->chunk_root_generation = root_item->generation;
963 super->chunk_root_level = root_item->level;
965 root_item = &root->fs_info->tree_root->root_item;
966 super->root = root_item->bytenr;
967 super->generation = root_item->generation;
968 super->root_level = root_item->level;
971 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
974 spin_lock(&info->new_trans_lock);
975 if (info->running_transaction)
976 ret = info->running_transaction->in_commit;
977 spin_unlock(&info->new_trans_lock);
981 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
984 spin_lock(&info->new_trans_lock);
985 if (info->running_transaction)
986 ret = info->running_transaction->blocked;
987 spin_unlock(&info->new_trans_lock);
991 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
992 struct btrfs_root *root)
994 unsigned long joined = 0;
995 unsigned long timeout = 1;
996 struct btrfs_transaction *cur_trans;
997 struct btrfs_transaction *prev_trans = NULL;
1000 int should_grow = 0;
1001 unsigned long now = get_seconds();
1002 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1004 btrfs_run_ordered_operations(root, 0);
1006 /* make a pass through all the delayed refs we have so far
1007 * any runnings procs may add more while we are here
1009 ret = btrfs_run_delayed_refs(trans, root, 0);
1012 btrfs_trans_release_metadata(trans, root);
1014 cur_trans = trans->transaction;
1016 * set the flushing flag so procs in this transaction have to
1017 * start sending their work down.
1019 cur_trans->delayed_refs.flushing = 1;
1021 ret = btrfs_run_delayed_refs(trans, root, 0);
1024 mutex_lock(&root->fs_info->trans_mutex);
1025 if (cur_trans->in_commit) {
1026 cur_trans->use_count++;
1027 mutex_unlock(&root->fs_info->trans_mutex);
1028 btrfs_end_transaction(trans, root);
1030 ret = wait_for_commit(root, cur_trans);
1033 mutex_lock(&root->fs_info->trans_mutex);
1034 put_transaction(cur_trans);
1035 mutex_unlock(&root->fs_info->trans_mutex);
1040 trans->transaction->in_commit = 1;
1041 trans->transaction->blocked = 1;
1042 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1043 prev_trans = list_entry(cur_trans->list.prev,
1044 struct btrfs_transaction, list);
1045 if (!prev_trans->commit_done) {
1046 prev_trans->use_count++;
1047 mutex_unlock(&root->fs_info->trans_mutex);
1049 wait_for_commit(root, prev_trans);
1051 mutex_lock(&root->fs_info->trans_mutex);
1052 put_transaction(prev_trans);
1056 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1060 int snap_pending = 0;
1061 joined = cur_trans->num_joined;
1062 if (!list_empty(&trans->transaction->pending_snapshots))
1065 WARN_ON(cur_trans != trans->transaction);
1066 if (cur_trans->num_writers > 1)
1067 timeout = MAX_SCHEDULE_TIMEOUT;
1068 else if (should_grow)
1071 mutex_unlock(&root->fs_info->trans_mutex);
1073 if (flush_on_commit || snap_pending) {
1074 btrfs_start_delalloc_inodes(root, 1);
1075 ret = btrfs_wait_ordered_extents(root, 0, 1);
1080 * rename don't use btrfs_join_transaction, so, once we
1081 * set the transaction to blocked above, we aren't going
1082 * to get any new ordered operations. We can safely run
1083 * it here and no for sure that nothing new will be added
1086 btrfs_run_ordered_operations(root, 1);
1088 prepare_to_wait(&cur_trans->writer_wait, &wait,
1089 TASK_UNINTERRUPTIBLE);
1092 if (cur_trans->num_writers > 1 || should_grow)
1093 schedule_timeout(timeout);
1095 mutex_lock(&root->fs_info->trans_mutex);
1096 finish_wait(&cur_trans->writer_wait, &wait);
1097 } while (cur_trans->num_writers > 1 ||
1098 (should_grow && cur_trans->num_joined != joined));
1100 ret = create_pending_snapshots(trans, root->fs_info);
1103 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1106 WARN_ON(cur_trans != trans->transaction);
1108 /* btrfs_commit_tree_roots is responsible for getting the
1109 * various roots consistent with each other. Every pointer
1110 * in the tree of tree roots has to point to the most up to date
1111 * root for every subvolume and other tree. So, we have to keep
1112 * the tree logging code from jumping in and changing any
1115 * At this point in the commit, there can't be any tree-log
1116 * writers, but a little lower down we drop the trans mutex
1117 * and let new people in. By holding the tree_log_mutex
1118 * from now until after the super is written, we avoid races
1119 * with the tree-log code.
1121 mutex_lock(&root->fs_info->tree_log_mutex);
1123 ret = commit_fs_roots(trans, root);
1126 /* commit_fs_roots gets rid of all the tree log roots, it is now
1127 * safe to free the root of tree log roots
1129 btrfs_free_log_root_tree(trans, root->fs_info);
1131 ret = commit_cowonly_roots(trans, root);
1134 btrfs_prepare_extent_commit(trans, root);
1136 cur_trans = root->fs_info->running_transaction;
1137 spin_lock(&root->fs_info->new_trans_lock);
1138 root->fs_info->running_transaction = NULL;
1139 spin_unlock(&root->fs_info->new_trans_lock);
1141 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1142 root->fs_info->tree_root->node);
1143 switch_commit_root(root->fs_info->tree_root);
1145 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1146 root->fs_info->chunk_root->node);
1147 switch_commit_root(root->fs_info->chunk_root);
1149 update_super_roots(root);
1151 if (!root->fs_info->log_root_recovering) {
1152 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1153 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1156 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1157 sizeof(root->fs_info->super_copy));
1159 trans->transaction->blocked = 0;
1161 wake_up(&root->fs_info->transaction_wait);
1163 mutex_unlock(&root->fs_info->trans_mutex);
1164 ret = btrfs_write_and_wait_transaction(trans, root);
1166 write_ctree_super(trans, root, 0);
1169 * the super is written, we can safely allow the tree-loggers
1170 * to go about their business
1172 mutex_unlock(&root->fs_info->tree_log_mutex);
1174 btrfs_finish_extent_commit(trans, root);
1176 mutex_lock(&root->fs_info->trans_mutex);
1178 cur_trans->commit_done = 1;
1180 root->fs_info->last_trans_committed = cur_trans->transid;
1182 wake_up(&cur_trans->commit_wait);
1184 put_transaction(cur_trans);
1185 put_transaction(cur_trans);
1187 mutex_unlock(&root->fs_info->trans_mutex);
1189 if (current->journal_info == trans)
1190 current->journal_info = NULL;
1192 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1194 if (current != root->fs_info->transaction_kthread)
1195 btrfs_run_delayed_iputs(root);
1201 * interface function to delete all the snapshots we have scheduled for deletion
1203 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1206 struct btrfs_fs_info *fs_info = root->fs_info;
1208 mutex_lock(&fs_info->trans_mutex);
1209 list_splice_init(&fs_info->dead_roots, &list);
1210 mutex_unlock(&fs_info->trans_mutex);
1212 while (!list_empty(&list)) {
1213 root = list_entry(list.next, struct btrfs_root, root_list);
1214 list_del(&root->root_list);
1216 if (btrfs_header_backref_rev(root->node) <
1217 BTRFS_MIXED_BACKREF_REV)
1218 btrfs_drop_snapshot(root, NULL, 0);
1220 btrfs_drop_snapshot(root, NULL, 1);