Merge branch 'for-chris' of git://git.kernel.org/pub/scm/linux/kernel/git/arne/btrfs...
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / btrfs / transaction.c
blobdc80f7156923ae120c5496f3fd0093a8616fbeec
1 /*
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.
19 #include <linux/fs.h>
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>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "locking.h"
29 #include "tree-log.h"
30 #include "inode-map.h"
32 #define BTRFS_ROOT_TRANS_TAG 0
34 static noinline void put_transaction(struct btrfs_transaction *transaction)
36 WARN_ON(atomic_read(&transaction->use_count) == 0);
37 if (atomic_dec_and_test(&transaction->use_count)) {
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;
56 if (!cur_trans) {
57 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
58 GFP_NOFS);
59 if (!cur_trans)
60 return -ENOMEM;
61 root->fs_info->generation++;
62 atomic_set(&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 atomic_set(&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);
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);
88 } else {
89 atomic_inc(&cur_trans->num_writers);
90 cur_trans->num_joined++;
93 return 0;
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);
115 return 0;
118 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
119 struct btrfs_root *root)
121 if (!root->ref_cows)
122 return 0;
124 mutex_lock(&root->fs_info->trans_mutex);
125 if (root->last_trans == trans->transid) {
126 mutex_unlock(&root->fs_info->trans_mutex);
127 return 0;
130 record_root_in_trans(trans, root);
131 mutex_unlock(&root->fs_info->trans_mutex);
132 return 0;
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) {
145 DEFINE_WAIT(wait);
146 atomic_inc(&cur_trans->use_count);
147 while (1) {
148 prepare_to_wait(&root->fs_info->transaction_wait, &wait,
149 TASK_UNINTERRUPTIBLE);
150 if (!cur_trans->blocked)
151 break;
152 mutex_unlock(&root->fs_info->trans_mutex);
153 schedule();
154 mutex_lock(&root->fs_info->trans_mutex);
156 finish_wait(&root->fs_info->transaction_wait, &wait);
157 put_transaction(cur_trans);
161 enum btrfs_trans_type {
162 TRANS_START,
163 TRANS_JOIN,
164 TRANS_USERSPACE,
165 TRANS_JOIN_NOLOCK,
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))
173 return 1;
174 return 0;
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;
182 int retries = 0;
183 int ret;
185 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
186 return ERR_PTR(-EROFS);
187 again:
188 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
189 if (!h)
190 return ERR_PTR(-ENOMEM);
192 if (type != TRANS_JOIN_NOLOCK)
193 mutex_lock(&root->fs_info->trans_mutex);
194 if (may_wait_transaction(root, type))
195 wait_current_trans(root);
197 ret = join_transaction(root);
198 if (ret < 0) {
199 kmem_cache_free(btrfs_trans_handle_cachep, h);
200 if (type != TRANS_JOIN_NOLOCK)
201 mutex_unlock(&root->fs_info->trans_mutex);
202 return ERR_PTR(ret);
205 cur_trans = root->fs_info->running_transaction;
206 atomic_inc(&cur_trans->use_count);
207 if (type != TRANS_JOIN_NOLOCK)
208 mutex_unlock(&root->fs_info->trans_mutex);
210 h->transid = cur_trans->transid;
211 h->transaction = cur_trans;
212 h->blocks_used = 0;
213 h->block_group = 0;
214 h->bytes_reserved = 0;
215 h->delayed_ref_updates = 0;
216 h->block_rsv = NULL;
218 smp_mb();
219 if (cur_trans->blocked && may_wait_transaction(root, type)) {
220 btrfs_commit_transaction(h, root);
221 goto again;
224 if (num_items > 0) {
225 ret = btrfs_trans_reserve_metadata(h, root, num_items);
226 if (ret == -EAGAIN && !retries) {
227 retries++;
228 btrfs_commit_transaction(h, root);
229 goto again;
230 } else if (ret == -EAGAIN) {
232 * We have already retried and got EAGAIN, so really we
233 * don't have space, so set ret to -ENOSPC.
235 ret = -ENOSPC;
238 if (ret < 0) {
239 btrfs_end_transaction(h, root);
240 return ERR_PTR(ret);
244 if (type != TRANS_JOIN_NOLOCK)
245 mutex_lock(&root->fs_info->trans_mutex);
246 record_root_in_trans(h, root);
247 if (type != TRANS_JOIN_NOLOCK)
248 mutex_unlock(&root->fs_info->trans_mutex);
250 if (!current->journal_info && type != TRANS_USERSPACE)
251 current->journal_info = h;
252 return h;
255 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
256 int num_items)
258 return start_transaction(root, num_items, TRANS_START);
260 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
261 int num_blocks)
263 return start_transaction(root, 0, TRANS_JOIN);
266 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root,
267 int num_blocks)
269 return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
272 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
273 int num_blocks)
275 return start_transaction(r, 0, TRANS_USERSPACE);
278 /* wait for a transaction commit to be fully complete */
279 static noinline int wait_for_commit(struct btrfs_root *root,
280 struct btrfs_transaction *commit)
282 DEFINE_WAIT(wait);
283 mutex_lock(&root->fs_info->trans_mutex);
284 while (!commit->commit_done) {
285 prepare_to_wait(&commit->commit_wait, &wait,
286 TASK_UNINTERRUPTIBLE);
287 if (commit->commit_done)
288 break;
289 mutex_unlock(&root->fs_info->trans_mutex);
290 schedule();
291 mutex_lock(&root->fs_info->trans_mutex);
293 mutex_unlock(&root->fs_info->trans_mutex);
294 finish_wait(&commit->commit_wait, &wait);
295 return 0;
298 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
300 struct btrfs_transaction *cur_trans = NULL, *t;
301 int ret;
303 mutex_lock(&root->fs_info->trans_mutex);
305 ret = 0;
306 if (transid) {
307 if (transid <= root->fs_info->last_trans_committed)
308 goto out_unlock;
310 /* find specified transaction */
311 list_for_each_entry(t, &root->fs_info->trans_list, list) {
312 if (t->transid == transid) {
313 cur_trans = t;
314 break;
316 if (t->transid > transid)
317 break;
319 ret = -EINVAL;
320 if (!cur_trans)
321 goto out_unlock; /* bad transid */
322 } else {
323 /* find newest transaction that is committing | committed */
324 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
325 list) {
326 if (t->in_commit) {
327 if (t->commit_done)
328 goto out_unlock;
329 cur_trans = t;
330 break;
333 if (!cur_trans)
334 goto out_unlock; /* nothing committing|committed */
337 atomic_inc(&cur_trans->use_count);
338 mutex_unlock(&root->fs_info->trans_mutex);
340 wait_for_commit(root, cur_trans);
342 mutex_lock(&root->fs_info->trans_mutex);
343 put_transaction(cur_trans);
344 ret = 0;
345 out_unlock:
346 mutex_unlock(&root->fs_info->trans_mutex);
347 return ret;
350 void btrfs_throttle(struct btrfs_root *root)
352 mutex_lock(&root->fs_info->trans_mutex);
353 if (!root->fs_info->open_ioctl_trans)
354 wait_current_trans(root);
355 mutex_unlock(&root->fs_info->trans_mutex);
358 static int should_end_transaction(struct btrfs_trans_handle *trans,
359 struct btrfs_root *root)
361 int ret;
362 ret = btrfs_block_rsv_check(trans, root,
363 &root->fs_info->global_block_rsv, 0, 5);
364 return ret ? 1 : 0;
367 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
368 struct btrfs_root *root)
370 struct btrfs_transaction *cur_trans = trans->transaction;
371 int updates;
373 if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
374 return 1;
376 updates = trans->delayed_ref_updates;
377 trans->delayed_ref_updates = 0;
378 if (updates)
379 btrfs_run_delayed_refs(trans, root, updates);
381 return should_end_transaction(trans, root);
384 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
385 struct btrfs_root *root, int throttle, int lock)
387 struct btrfs_transaction *cur_trans = trans->transaction;
388 struct btrfs_fs_info *info = root->fs_info;
389 int count = 0;
391 while (count < 4) {
392 unsigned long cur = trans->delayed_ref_updates;
393 trans->delayed_ref_updates = 0;
394 if (cur &&
395 trans->transaction->delayed_refs.num_heads_ready > 64) {
396 trans->delayed_ref_updates = 0;
399 * do a full flush if the transaction is trying
400 * to close
402 if (trans->transaction->delayed_refs.flushing)
403 cur = 0;
404 btrfs_run_delayed_refs(trans, root, cur);
405 } else {
406 break;
408 count++;
411 btrfs_trans_release_metadata(trans, root);
413 if (lock && !root->fs_info->open_ioctl_trans &&
414 should_end_transaction(trans, root))
415 trans->transaction->blocked = 1;
417 if (lock && cur_trans->blocked && !cur_trans->in_commit) {
418 if (throttle)
419 return btrfs_commit_transaction(trans, root);
420 else
421 wake_up_process(info->transaction_kthread);
424 WARN_ON(cur_trans != info->running_transaction);
425 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
426 atomic_dec(&cur_trans->num_writers);
428 smp_mb();
429 if (waitqueue_active(&cur_trans->writer_wait))
430 wake_up(&cur_trans->writer_wait);
431 put_transaction(cur_trans);
433 if (current->journal_info == trans)
434 current->journal_info = NULL;
435 memset(trans, 0, sizeof(*trans));
436 kmem_cache_free(btrfs_trans_handle_cachep, trans);
438 if (throttle)
439 btrfs_run_delayed_iputs(root);
441 return 0;
444 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
445 struct btrfs_root *root)
447 int ret;
449 ret = __btrfs_end_transaction(trans, root, 0, 1);
450 if (ret)
451 return ret;
452 return 0;
455 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
456 struct btrfs_root *root)
458 int ret;
460 ret = __btrfs_end_transaction(trans, root, 1, 1);
461 if (ret)
462 return ret;
463 return 0;
466 int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
467 struct btrfs_root *root)
469 int ret;
471 ret = __btrfs_end_transaction(trans, root, 0, 0);
472 if (ret)
473 return ret;
474 return 0;
477 int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
478 struct btrfs_root *root)
480 return __btrfs_end_transaction(trans, root, 1, 1);
484 * when btree blocks are allocated, they have some corresponding bits set for
485 * them in one of two extent_io trees. This is used to make sure all of
486 * those extents are sent to disk but does not wait on them
488 int btrfs_write_marked_extents(struct btrfs_root *root,
489 struct extent_io_tree *dirty_pages, int mark)
491 int ret;
492 int err = 0;
493 int werr = 0;
494 struct page *page;
495 struct inode *btree_inode = root->fs_info->btree_inode;
496 u64 start = 0;
497 u64 end;
498 unsigned long index;
500 while (1) {
501 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
502 mark);
503 if (ret)
504 break;
505 while (start <= end) {
506 cond_resched();
508 index = start >> PAGE_CACHE_SHIFT;
509 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
510 page = find_get_page(btree_inode->i_mapping, index);
511 if (!page)
512 continue;
514 btree_lock_page_hook(page);
515 if (!page->mapping) {
516 unlock_page(page);
517 page_cache_release(page);
518 continue;
521 if (PageWriteback(page)) {
522 if (PageDirty(page))
523 wait_on_page_writeback(page);
524 else {
525 unlock_page(page);
526 page_cache_release(page);
527 continue;
530 err = write_one_page(page, 0);
531 if (err)
532 werr = err;
533 page_cache_release(page);
536 if (err)
537 werr = err;
538 return werr;
542 * when btree blocks are allocated, they have some corresponding bits set for
543 * them in one of two extent_io trees. This is used to make sure all of
544 * those extents are on disk for transaction or log commit. We wait
545 * on all the pages and clear them from the dirty pages state tree
547 int btrfs_wait_marked_extents(struct btrfs_root *root,
548 struct extent_io_tree *dirty_pages, int mark)
550 int ret;
551 int err = 0;
552 int werr = 0;
553 struct page *page;
554 struct inode *btree_inode = root->fs_info->btree_inode;
555 u64 start = 0;
556 u64 end;
557 unsigned long index;
559 while (1) {
560 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
561 mark);
562 if (ret)
563 break;
565 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
566 while (start <= end) {
567 index = start >> PAGE_CACHE_SHIFT;
568 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
569 page = find_get_page(btree_inode->i_mapping, index);
570 if (!page)
571 continue;
572 if (PageDirty(page)) {
573 btree_lock_page_hook(page);
574 wait_on_page_writeback(page);
575 err = write_one_page(page, 0);
576 if (err)
577 werr = err;
579 wait_on_page_writeback(page);
580 page_cache_release(page);
581 cond_resched();
584 if (err)
585 werr = err;
586 return werr;
590 * when btree blocks are allocated, they have some corresponding bits set for
591 * them in one of two extent_io trees. This is used to make sure all of
592 * those extents are on disk for transaction or log commit
594 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
595 struct extent_io_tree *dirty_pages, int mark)
597 int ret;
598 int ret2;
600 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
601 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
602 return ret || ret2;
605 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
606 struct btrfs_root *root)
608 if (!trans || !trans->transaction) {
609 struct inode *btree_inode;
610 btree_inode = root->fs_info->btree_inode;
611 return filemap_write_and_wait(btree_inode->i_mapping);
613 return btrfs_write_and_wait_marked_extents(root,
614 &trans->transaction->dirty_pages,
615 EXTENT_DIRTY);
619 * this is used to update the root pointer in the tree of tree roots.
621 * But, in the case of the extent allocation tree, updating the root
622 * pointer may allocate blocks which may change the root of the extent
623 * allocation tree.
625 * So, this loops and repeats and makes sure the cowonly root didn't
626 * change while the root pointer was being updated in the metadata.
628 static int update_cowonly_root(struct btrfs_trans_handle *trans,
629 struct btrfs_root *root)
631 int ret;
632 u64 old_root_bytenr;
633 u64 old_root_used;
634 struct btrfs_root *tree_root = root->fs_info->tree_root;
636 old_root_used = btrfs_root_used(&root->root_item);
637 btrfs_write_dirty_block_groups(trans, root);
639 while (1) {
640 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
641 if (old_root_bytenr == root->node->start &&
642 old_root_used == btrfs_root_used(&root->root_item))
643 break;
645 btrfs_set_root_node(&root->root_item, root->node);
646 ret = btrfs_update_root(trans, tree_root,
647 &root->root_key,
648 &root->root_item);
649 BUG_ON(ret);
651 old_root_used = btrfs_root_used(&root->root_item);
652 ret = btrfs_write_dirty_block_groups(trans, root);
653 BUG_ON(ret);
656 if (root != root->fs_info->extent_root)
657 switch_commit_root(root);
659 return 0;
663 * update all the cowonly tree roots on disk
665 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
666 struct btrfs_root *root)
668 struct btrfs_fs_info *fs_info = root->fs_info;
669 struct list_head *next;
670 struct extent_buffer *eb;
671 int ret;
673 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
674 BUG_ON(ret);
676 eb = btrfs_lock_root_node(fs_info->tree_root);
677 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
678 btrfs_tree_unlock(eb);
679 free_extent_buffer(eb);
681 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
682 BUG_ON(ret);
684 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
685 next = fs_info->dirty_cowonly_roots.next;
686 list_del_init(next);
687 root = list_entry(next, struct btrfs_root, dirty_list);
689 update_cowonly_root(trans, root);
692 down_write(&fs_info->extent_commit_sem);
693 switch_commit_root(fs_info->extent_root);
694 up_write(&fs_info->extent_commit_sem);
696 return 0;
700 * dead roots are old snapshots that need to be deleted. This allocates
701 * a dirty root struct and adds it into the list of dead roots that need to
702 * be deleted
704 int btrfs_add_dead_root(struct btrfs_root *root)
706 mutex_lock(&root->fs_info->trans_mutex);
707 list_add(&root->root_list, &root->fs_info->dead_roots);
708 mutex_unlock(&root->fs_info->trans_mutex);
709 return 0;
713 * update all the cowonly tree roots on disk
715 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
716 struct btrfs_root *root)
718 struct btrfs_root *gang[8];
719 struct btrfs_fs_info *fs_info = root->fs_info;
720 int i;
721 int ret;
722 int err = 0;
724 while (1) {
725 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
726 (void **)gang, 0,
727 ARRAY_SIZE(gang),
728 BTRFS_ROOT_TRANS_TAG);
729 if (ret == 0)
730 break;
731 for (i = 0; i < ret; i++) {
732 root = gang[i];
733 radix_tree_tag_clear(&fs_info->fs_roots_radix,
734 (unsigned long)root->root_key.objectid,
735 BTRFS_ROOT_TRANS_TAG);
737 btrfs_free_log(trans, root);
738 btrfs_update_reloc_root(trans, root);
739 btrfs_orphan_commit_root(trans, root);
741 btrfs_save_ino_cache(root, trans);
743 if (root->commit_root != root->node) {
744 mutex_lock(&root->fs_commit_mutex);
745 switch_commit_root(root);
746 btrfs_unpin_free_ino(root);
747 mutex_unlock(&root->fs_commit_mutex);
749 btrfs_set_root_node(&root->root_item,
750 root->node);
753 err = btrfs_update_root(trans, fs_info->tree_root,
754 &root->root_key,
755 &root->root_item);
756 if (err)
757 break;
760 return err;
764 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
765 * otherwise every leaf in the btree is read and defragged.
767 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
769 struct btrfs_fs_info *info = root->fs_info;
770 struct btrfs_trans_handle *trans;
771 int ret;
772 unsigned long nr;
774 if (xchg(&root->defrag_running, 1))
775 return 0;
777 while (1) {
778 trans = btrfs_start_transaction(root, 0);
779 if (IS_ERR(trans))
780 return PTR_ERR(trans);
782 ret = btrfs_defrag_leaves(trans, root, cacheonly);
784 nr = trans->blocks_used;
785 btrfs_end_transaction(trans, root);
786 btrfs_btree_balance_dirty(info->tree_root, nr);
787 cond_resched();
789 if (root->fs_info->closing || ret != -EAGAIN)
790 break;
792 root->defrag_running = 0;
793 return ret;
797 * new snapshots need to be created at a very specific time in the
798 * transaction commit. This does the actual creation
800 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
801 struct btrfs_fs_info *fs_info,
802 struct btrfs_pending_snapshot *pending)
804 struct btrfs_key key;
805 struct btrfs_root_item *new_root_item;
806 struct btrfs_root *tree_root = fs_info->tree_root;
807 struct btrfs_root *root = pending->root;
808 struct btrfs_root *parent_root;
809 struct inode *parent_inode;
810 struct dentry *parent;
811 struct dentry *dentry;
812 struct extent_buffer *tmp;
813 struct extent_buffer *old;
814 int ret;
815 u64 to_reserve = 0;
816 u64 index = 0;
817 u64 objectid;
818 u64 root_flags;
820 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
821 if (!new_root_item) {
822 pending->error = -ENOMEM;
823 goto fail;
826 ret = btrfs_find_free_objectid(tree_root, &objectid);
827 if (ret) {
828 pending->error = ret;
829 goto fail;
832 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
833 btrfs_orphan_pre_snapshot(trans, pending, &to_reserve);
835 if (to_reserve > 0) {
836 ret = btrfs_block_rsv_add(trans, root, &pending->block_rsv,
837 to_reserve);
838 if (ret) {
839 pending->error = ret;
840 goto fail;
844 key.objectid = objectid;
845 key.offset = (u64)-1;
846 key.type = BTRFS_ROOT_ITEM_KEY;
848 trans->block_rsv = &pending->block_rsv;
850 dentry = pending->dentry;
851 parent = dget_parent(dentry);
852 parent_inode = parent->d_inode;
853 parent_root = BTRFS_I(parent_inode)->root;
854 record_root_in_trans(trans, parent_root);
857 * insert the directory item
859 ret = btrfs_set_inode_index(parent_inode, &index);
860 BUG_ON(ret);
861 ret = btrfs_insert_dir_item(trans, parent_root,
862 dentry->d_name.name, dentry->d_name.len,
863 parent_inode, &key,
864 BTRFS_FT_DIR, index);
865 BUG_ON(ret);
867 btrfs_i_size_write(parent_inode, parent_inode->i_size +
868 dentry->d_name.len * 2);
869 ret = btrfs_update_inode(trans, parent_root, parent_inode);
870 BUG_ON(ret);
872 record_root_in_trans(trans, root);
873 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
874 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
875 btrfs_check_and_init_root_item(new_root_item);
877 root_flags = btrfs_root_flags(new_root_item);
878 if (pending->readonly)
879 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
880 else
881 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
882 btrfs_set_root_flags(new_root_item, root_flags);
884 old = btrfs_lock_root_node(root);
885 btrfs_cow_block(trans, root, old, NULL, 0, &old);
886 btrfs_set_lock_blocking(old);
888 btrfs_copy_root(trans, root, old, &tmp, objectid);
889 btrfs_tree_unlock(old);
890 free_extent_buffer(old);
892 btrfs_set_root_node(new_root_item, tmp);
893 /* record when the snapshot was created in key.offset */
894 key.offset = trans->transid;
895 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
896 btrfs_tree_unlock(tmp);
897 free_extent_buffer(tmp);
898 BUG_ON(ret);
901 * insert root back/forward references
903 ret = btrfs_add_root_ref(trans, tree_root, objectid,
904 parent_root->root_key.objectid,
905 btrfs_ino(parent_inode), index,
906 dentry->d_name.name, dentry->d_name.len);
907 BUG_ON(ret);
908 dput(parent);
910 key.offset = (u64)-1;
911 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
912 BUG_ON(IS_ERR(pending->snap));
914 btrfs_reloc_post_snapshot(trans, pending);
915 btrfs_orphan_post_snapshot(trans, pending);
916 fail:
917 kfree(new_root_item);
918 btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
919 return 0;
923 * create all the snapshots we've scheduled for creation
925 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
926 struct btrfs_fs_info *fs_info)
928 struct btrfs_pending_snapshot *pending;
929 struct list_head *head = &trans->transaction->pending_snapshots;
930 int ret;
932 list_for_each_entry(pending, head, list) {
934 * We must deal with the delayed items before creating
935 * snapshots, or we will create a snapthot with inconsistent
936 * information.
938 ret = btrfs_run_delayed_items(trans, fs_info->fs_root);
939 BUG_ON(ret);
941 ret = create_pending_snapshot(trans, fs_info, pending);
942 BUG_ON(ret);
944 return 0;
947 static void update_super_roots(struct btrfs_root *root)
949 struct btrfs_root_item *root_item;
950 struct btrfs_super_block *super;
952 super = &root->fs_info->super_copy;
954 root_item = &root->fs_info->chunk_root->root_item;
955 super->chunk_root = root_item->bytenr;
956 super->chunk_root_generation = root_item->generation;
957 super->chunk_root_level = root_item->level;
959 root_item = &root->fs_info->tree_root->root_item;
960 super->root = root_item->bytenr;
961 super->generation = root_item->generation;
962 super->root_level = root_item->level;
963 if (super->cache_generation != 0 || btrfs_test_opt(root, SPACE_CACHE))
964 super->cache_generation = root_item->generation;
967 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
969 int ret = 0;
970 spin_lock(&info->new_trans_lock);
971 if (info->running_transaction)
972 ret = info->running_transaction->in_commit;
973 spin_unlock(&info->new_trans_lock);
974 return ret;
977 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
979 int ret = 0;
980 spin_lock(&info->new_trans_lock);
981 if (info->running_transaction)
982 ret = info->running_transaction->blocked;
983 spin_unlock(&info->new_trans_lock);
984 return ret;
988 * wait for the current transaction commit to start and block subsequent
989 * transaction joins
991 static void wait_current_trans_commit_start(struct btrfs_root *root,
992 struct btrfs_transaction *trans)
994 DEFINE_WAIT(wait);
996 if (trans->in_commit)
997 return;
999 while (1) {
1000 prepare_to_wait(&root->fs_info->transaction_blocked_wait, &wait,
1001 TASK_UNINTERRUPTIBLE);
1002 if (trans->in_commit) {
1003 finish_wait(&root->fs_info->transaction_blocked_wait,
1004 &wait);
1005 break;
1007 mutex_unlock(&root->fs_info->trans_mutex);
1008 schedule();
1009 mutex_lock(&root->fs_info->trans_mutex);
1010 finish_wait(&root->fs_info->transaction_blocked_wait, &wait);
1015 * wait for the current transaction to start and then become unblocked.
1016 * caller holds ref.
1018 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1019 struct btrfs_transaction *trans)
1021 DEFINE_WAIT(wait);
1023 if (trans->commit_done || (trans->in_commit && !trans->blocked))
1024 return;
1026 while (1) {
1027 prepare_to_wait(&root->fs_info->transaction_wait, &wait,
1028 TASK_UNINTERRUPTIBLE);
1029 if (trans->commit_done ||
1030 (trans->in_commit && !trans->blocked)) {
1031 finish_wait(&root->fs_info->transaction_wait,
1032 &wait);
1033 break;
1035 mutex_unlock(&root->fs_info->trans_mutex);
1036 schedule();
1037 mutex_lock(&root->fs_info->trans_mutex);
1038 finish_wait(&root->fs_info->transaction_wait,
1039 &wait);
1044 * commit transactions asynchronously. once btrfs_commit_transaction_async
1045 * returns, any subsequent transaction will not be allowed to join.
1047 struct btrfs_async_commit {
1048 struct btrfs_trans_handle *newtrans;
1049 struct btrfs_root *root;
1050 struct delayed_work work;
1053 static void do_async_commit(struct work_struct *work)
1055 struct btrfs_async_commit *ac =
1056 container_of(work, struct btrfs_async_commit, work.work);
1058 btrfs_commit_transaction(ac->newtrans, ac->root);
1059 kfree(ac);
1062 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1063 struct btrfs_root *root,
1064 int wait_for_unblock)
1066 struct btrfs_async_commit *ac;
1067 struct btrfs_transaction *cur_trans;
1069 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1070 if (!ac)
1071 return -ENOMEM;
1073 INIT_DELAYED_WORK(&ac->work, do_async_commit);
1074 ac->root = root;
1075 ac->newtrans = btrfs_join_transaction(root, 0);
1076 if (IS_ERR(ac->newtrans)) {
1077 int err = PTR_ERR(ac->newtrans);
1078 kfree(ac);
1079 return err;
1082 /* take transaction reference */
1083 mutex_lock(&root->fs_info->trans_mutex);
1084 cur_trans = trans->transaction;
1085 atomic_inc(&cur_trans->use_count);
1086 mutex_unlock(&root->fs_info->trans_mutex);
1088 btrfs_end_transaction(trans, root);
1089 schedule_delayed_work(&ac->work, 0);
1091 /* wait for transaction to start and unblock */
1092 mutex_lock(&root->fs_info->trans_mutex);
1093 if (wait_for_unblock)
1094 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1095 else
1096 wait_current_trans_commit_start(root, cur_trans);
1097 put_transaction(cur_trans);
1098 mutex_unlock(&root->fs_info->trans_mutex);
1100 return 0;
1104 * btrfs_transaction state sequence:
1105 * in_commit = 0, blocked = 0 (initial)
1106 * in_commit = 1, blocked = 1
1107 * blocked = 0
1108 * commit_done = 1
1110 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1111 struct btrfs_root *root)
1113 unsigned long joined = 0;
1114 struct btrfs_transaction *cur_trans;
1115 struct btrfs_transaction *prev_trans = NULL;
1116 DEFINE_WAIT(wait);
1117 int ret;
1118 int should_grow = 0;
1119 unsigned long now = get_seconds();
1120 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1122 btrfs_run_ordered_operations(root, 0);
1124 /* make a pass through all the delayed refs we have so far
1125 * any runnings procs may add more while we are here
1127 ret = btrfs_run_delayed_refs(trans, root, 0);
1128 BUG_ON(ret);
1130 btrfs_trans_release_metadata(trans, root);
1132 cur_trans = trans->transaction;
1134 * set the flushing flag so procs in this transaction have to
1135 * start sending their work down.
1137 cur_trans->delayed_refs.flushing = 1;
1139 ret = btrfs_run_delayed_refs(trans, root, 0);
1140 BUG_ON(ret);
1142 mutex_lock(&root->fs_info->trans_mutex);
1143 if (cur_trans->in_commit) {
1144 atomic_inc(&cur_trans->use_count);
1145 mutex_unlock(&root->fs_info->trans_mutex);
1146 btrfs_end_transaction(trans, root);
1148 ret = wait_for_commit(root, cur_trans);
1149 BUG_ON(ret);
1151 mutex_lock(&root->fs_info->trans_mutex);
1152 put_transaction(cur_trans);
1153 mutex_unlock(&root->fs_info->trans_mutex);
1155 return 0;
1158 trans->transaction->in_commit = 1;
1159 trans->transaction->blocked = 1;
1160 wake_up(&root->fs_info->transaction_blocked_wait);
1162 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1163 prev_trans = list_entry(cur_trans->list.prev,
1164 struct btrfs_transaction, list);
1165 if (!prev_trans->commit_done) {
1166 atomic_inc(&prev_trans->use_count);
1167 mutex_unlock(&root->fs_info->trans_mutex);
1169 wait_for_commit(root, prev_trans);
1171 mutex_lock(&root->fs_info->trans_mutex);
1172 put_transaction(prev_trans);
1176 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1177 should_grow = 1;
1179 do {
1180 int snap_pending = 0;
1181 joined = cur_trans->num_joined;
1182 if (!list_empty(&trans->transaction->pending_snapshots))
1183 snap_pending = 1;
1185 WARN_ON(cur_trans != trans->transaction);
1186 mutex_unlock(&root->fs_info->trans_mutex);
1188 if (flush_on_commit || snap_pending) {
1189 btrfs_start_delalloc_inodes(root, 1);
1190 ret = btrfs_wait_ordered_extents(root, 0, 1);
1191 BUG_ON(ret);
1194 ret = btrfs_run_delayed_items(trans, root);
1195 BUG_ON(ret);
1198 * rename don't use btrfs_join_transaction, so, once we
1199 * set the transaction to blocked above, we aren't going
1200 * to get any new ordered operations. We can safely run
1201 * it here and no for sure that nothing new will be added
1202 * to the list
1204 btrfs_run_ordered_operations(root, 1);
1206 prepare_to_wait(&cur_trans->writer_wait, &wait,
1207 TASK_UNINTERRUPTIBLE);
1209 smp_mb();
1210 if (atomic_read(&cur_trans->num_writers) > 1)
1211 schedule_timeout(MAX_SCHEDULE_TIMEOUT);
1212 else if (should_grow)
1213 schedule_timeout(1);
1215 mutex_lock(&root->fs_info->trans_mutex);
1216 finish_wait(&cur_trans->writer_wait, &wait);
1217 } while (atomic_read(&cur_trans->num_writers) > 1 ||
1218 (should_grow && cur_trans->num_joined != joined));
1220 ret = create_pending_snapshots(trans, root->fs_info);
1221 BUG_ON(ret);
1223 ret = btrfs_run_delayed_items(trans, root);
1224 BUG_ON(ret);
1226 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1227 BUG_ON(ret);
1229 WARN_ON(cur_trans != trans->transaction);
1231 btrfs_scrub_pause(root);
1232 /* btrfs_commit_tree_roots is responsible for getting the
1233 * various roots consistent with each other. Every pointer
1234 * in the tree of tree roots has to point to the most up to date
1235 * root for every subvolume and other tree. So, we have to keep
1236 * the tree logging code from jumping in and changing any
1237 * of the trees.
1239 * At this point in the commit, there can't be any tree-log
1240 * writers, but a little lower down we drop the trans mutex
1241 * and let new people in. By holding the tree_log_mutex
1242 * from now until after the super is written, we avoid races
1243 * with the tree-log code.
1245 mutex_lock(&root->fs_info->tree_log_mutex);
1247 ret = commit_fs_roots(trans, root);
1248 BUG_ON(ret);
1250 /* commit_fs_roots gets rid of all the tree log roots, it is now
1251 * safe to free the root of tree log roots
1253 btrfs_free_log_root_tree(trans, root->fs_info);
1255 ret = commit_cowonly_roots(trans, root);
1256 BUG_ON(ret);
1258 btrfs_prepare_extent_commit(trans, root);
1260 cur_trans = root->fs_info->running_transaction;
1261 spin_lock(&root->fs_info->new_trans_lock);
1262 root->fs_info->running_transaction = NULL;
1263 spin_unlock(&root->fs_info->new_trans_lock);
1265 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1266 root->fs_info->tree_root->node);
1267 switch_commit_root(root->fs_info->tree_root);
1269 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1270 root->fs_info->chunk_root->node);
1271 switch_commit_root(root->fs_info->chunk_root);
1273 update_super_roots(root);
1275 if (!root->fs_info->log_root_recovering) {
1276 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1277 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1280 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1281 sizeof(root->fs_info->super_copy));
1283 trans->transaction->blocked = 0;
1285 wake_up(&root->fs_info->transaction_wait);
1287 mutex_unlock(&root->fs_info->trans_mutex);
1288 ret = btrfs_write_and_wait_transaction(trans, root);
1289 BUG_ON(ret);
1290 write_ctree_super(trans, root, 0);
1293 * the super is written, we can safely allow the tree-loggers
1294 * to go about their business
1296 mutex_unlock(&root->fs_info->tree_log_mutex);
1298 btrfs_finish_extent_commit(trans, root);
1300 mutex_lock(&root->fs_info->trans_mutex);
1302 cur_trans->commit_done = 1;
1304 root->fs_info->last_trans_committed = cur_trans->transid;
1306 wake_up(&cur_trans->commit_wait);
1308 list_del_init(&cur_trans->list);
1309 put_transaction(cur_trans);
1310 put_transaction(cur_trans);
1312 trace_btrfs_transaction_commit(root);
1314 mutex_unlock(&root->fs_info->trans_mutex);
1316 btrfs_scrub_continue(root);
1318 if (current->journal_info == trans)
1319 current->journal_info = NULL;
1321 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1323 if (current != root->fs_info->transaction_kthread)
1324 btrfs_run_delayed_iputs(root);
1326 return ret;
1330 * interface function to delete all the snapshots we have scheduled for deletion
1332 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1334 LIST_HEAD(list);
1335 struct btrfs_fs_info *fs_info = root->fs_info;
1337 mutex_lock(&fs_info->trans_mutex);
1338 list_splice_init(&fs_info->dead_roots, &list);
1339 mutex_unlock(&fs_info->trans_mutex);
1341 while (!list_empty(&list)) {
1342 root = list_entry(list.next, struct btrfs_root, root_list);
1343 list_del(&root->root_list);
1345 btrfs_kill_all_delayed_nodes(root);
1347 if (btrfs_header_backref_rev(root->node) <
1348 BTRFS_MIXED_BACKREF_REV)
1349 btrfs_drop_snapshot(root, NULL, 0);
1350 else
1351 btrfs_drop_snapshot(root, NULL, 1);
1353 return 0;