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1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
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"
31
32#define BTRFS_ROOT_TRANS_TAG 0
33
34static noinline void put_transaction(struct btrfs_transaction *transaction)
35{
36 WARN_ON(atomic_read(&transaction->use_count) == 0);
37 if (atomic_dec_and_test(&transaction->use_count)) {
38 BUG_ON(!list_empty(&transaction->list));
39 memset(transaction, 0, sizeof(*transaction));
40 kmem_cache_free(btrfs_transaction_cachep, transaction);
41 }
42}
43
44static noinline void switch_commit_root(struct btrfs_root *root)
45{
46 free_extent_buffer(root->commit_root);
47 root->commit_root = btrfs_root_node(root);
48}
49
50/*
51 * either allocate a new transaction or hop into the existing one
52 */
53static noinline int join_transaction(struct btrfs_root *root, int nofail)
54{
55 struct btrfs_transaction *cur_trans;
56
57 spin_lock(&root->fs_info->trans_lock);
58 if (root->fs_info->trans_no_join) {
59 if (!nofail) {
60 spin_unlock(&root->fs_info->trans_lock);
61 return -EBUSY;
62 }
63 }
64
65 cur_trans = root->fs_info->running_transaction;
66 if (cur_trans) {
67 atomic_inc(&cur_trans->use_count);
68 atomic_inc(&cur_trans->num_writers);
69 cur_trans->num_joined++;
70 spin_unlock(&root->fs_info->trans_lock);
71 return 0;
72 }
73 spin_unlock(&root->fs_info->trans_lock);
74
75 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
76 if (!cur_trans)
77 return -ENOMEM;
78 spin_lock(&root->fs_info->trans_lock);
79 if (root->fs_info->running_transaction) {
80 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
81 cur_trans = root->fs_info->running_transaction;
82 atomic_inc(&cur_trans->use_count);
83 atomic_inc(&cur_trans->num_writers);
84 cur_trans->num_joined++;
85 spin_unlock(&root->fs_info->trans_lock);
86 return 0;
87 }
88 atomic_set(&cur_trans->num_writers, 1);
89 cur_trans->num_joined = 0;
90 init_waitqueue_head(&cur_trans->writer_wait);
91 init_waitqueue_head(&cur_trans->commit_wait);
92 cur_trans->in_commit = 0;
93 cur_trans->blocked = 0;
94 /*
95 * One for this trans handle, one so it will live on until we
96 * commit the transaction.
97 */
98 atomic_set(&cur_trans->use_count, 2);
99 cur_trans->commit_done = 0;
100 cur_trans->start_time = get_seconds();
101
102 cur_trans->delayed_refs.root = RB_ROOT;
103 cur_trans->delayed_refs.num_entries = 0;
104 cur_trans->delayed_refs.num_heads_ready = 0;
105 cur_trans->delayed_refs.num_heads = 0;
106 cur_trans->delayed_refs.flushing = 0;
107 cur_trans->delayed_refs.run_delayed_start = 0;
108 spin_lock_init(&cur_trans->commit_lock);
109 spin_lock_init(&cur_trans->delayed_refs.lock);
110
111 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
112 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
113 extent_io_tree_init(&cur_trans->dirty_pages,
114 root->fs_info->btree_inode->i_mapping);
115 root->fs_info->generation++;
116 cur_trans->transid = root->fs_info->generation;
117 root->fs_info->running_transaction = cur_trans;
118 spin_unlock(&root->fs_info->trans_lock);
119
120 return 0;
121}
122
123/*
124 * this does all the record keeping required to make sure that a reference
125 * counted root is properly recorded in a given transaction. This is required
126 * to make sure the old root from before we joined the transaction is deleted
127 * when the transaction commits
128 */
129static int record_root_in_trans(struct btrfs_trans_handle *trans,
130 struct btrfs_root *root)
131{
132 if (root->ref_cows && root->last_trans < trans->transid) {
133 WARN_ON(root == root->fs_info->extent_root);
134 WARN_ON(root->commit_root != root->node);
135
136 /*
137 * see below for in_trans_setup usage rules
138 * we have the reloc mutex held now, so there
139 * is only one writer in this function
140 */
141 root->in_trans_setup = 1;
142
143 /* make sure readers find in_trans_setup before
144 * they find our root->last_trans update
145 */
146 smp_wmb();
147
148 spin_lock(&root->fs_info->fs_roots_radix_lock);
149 if (root->last_trans == trans->transid) {
150 spin_unlock(&root->fs_info->fs_roots_radix_lock);
151 return 0;
152 }
153 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
154 (unsigned long)root->root_key.objectid,
155 BTRFS_ROOT_TRANS_TAG);
156 spin_unlock(&root->fs_info->fs_roots_radix_lock);
157 root->last_trans = trans->transid;
158
159 /* this is pretty tricky. We don't want to
160 * take the relocation lock in btrfs_record_root_in_trans
161 * unless we're really doing the first setup for this root in
162 * this transaction.
163 *
164 * Normally we'd use root->last_trans as a flag to decide
165 * if we want to take the expensive mutex.
166 *
167 * But, we have to set root->last_trans before we
168 * init the relocation root, otherwise, we trip over warnings
169 * in ctree.c. The solution used here is to flag ourselves
170 * with root->in_trans_setup. When this is 1, we're still
171 * fixing up the reloc trees and everyone must wait.
172 *
173 * When this is zero, they can trust root->last_trans and fly
174 * through btrfs_record_root_in_trans without having to take the
175 * lock. smp_wmb() makes sure that all the writes above are
176 * done before we pop in the zero below
177 */
178 btrfs_init_reloc_root(trans, root);
179 smp_wmb();
180 root->in_trans_setup = 0;
181 }
182 return 0;
183}
184
185
186int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
187 struct btrfs_root *root)
188{
189 if (!root->ref_cows)
190 return 0;
191
192 /*
193 * see record_root_in_trans for comments about in_trans_setup usage
194 * and barriers
195 */
196 smp_rmb();
197 if (root->last_trans == trans->transid &&
198 !root->in_trans_setup)
199 return 0;
200
201 mutex_lock(&root->fs_info->reloc_mutex);
202 record_root_in_trans(trans, root);
203 mutex_unlock(&root->fs_info->reloc_mutex);
204
205 return 0;
206}
207
208/* wait for commit against the current transaction to become unblocked
209 * when this is done, it is safe to start a new transaction, but the current
210 * transaction might not be fully on disk.
211 */
212static void wait_current_trans(struct btrfs_root *root)
213{
214 struct btrfs_transaction *cur_trans;
215
216 spin_lock(&root->fs_info->trans_lock);
217 cur_trans = root->fs_info->running_transaction;
218 if (cur_trans && cur_trans->blocked) {
219 atomic_inc(&cur_trans->use_count);
220 spin_unlock(&root->fs_info->trans_lock);
221
222 wait_event(root->fs_info->transaction_wait,
223 !cur_trans->blocked);
224 put_transaction(cur_trans);
225 } else {
226 spin_unlock(&root->fs_info->trans_lock);
227 }
228}
229
230enum btrfs_trans_type {
231 TRANS_START,
232 TRANS_JOIN,
233 TRANS_USERSPACE,
234 TRANS_JOIN_NOLOCK,
235};
236
237static int may_wait_transaction(struct btrfs_root *root, int type)
238{
239 if (root->fs_info->log_root_recovering)
240 return 0;
241
242 if (type == TRANS_USERSPACE)
243 return 1;
244
245 if (type == TRANS_START &&
246 !atomic_read(&root->fs_info->open_ioctl_trans))
247 return 1;
248
249 return 0;
250}
251
252static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
253 u64 num_items, int type)
254{
255 struct btrfs_trans_handle *h;
256 struct btrfs_transaction *cur_trans;
257 u64 num_bytes = 0;
258 int ret;
259
260 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
261 return ERR_PTR(-EROFS);
262
263 if (current->journal_info) {
264 WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
265 h = current->journal_info;
266 h->use_count++;
267 h->orig_rsv = h->block_rsv;
268 h->block_rsv = NULL;
269 goto got_it;
270 }
271
272 /*
273 * Do the reservation before we join the transaction so we can do all
274 * the appropriate flushing if need be.
275 */
276 if (num_items > 0 && root != root->fs_info->chunk_root) {
277 num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
278 ret = btrfs_block_rsv_add(NULL, root,
279 &root->fs_info->trans_block_rsv,
280 num_bytes);
281 if (ret)
282 return ERR_PTR(ret);
283 }
284again:
285 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
286 if (!h)
287 return ERR_PTR(-ENOMEM);
288
289 if (may_wait_transaction(root, type))
290 wait_current_trans(root);
291
292 do {
293 ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
294 if (ret == -EBUSY)
295 wait_current_trans(root);
296 } while (ret == -EBUSY);
297
298 if (ret < 0) {
299 kmem_cache_free(btrfs_trans_handle_cachep, h);
300 return ERR_PTR(ret);
301 }
302
303 cur_trans = root->fs_info->running_transaction;
304
305 h->transid = cur_trans->transid;
306 h->transaction = cur_trans;
307 h->blocks_used = 0;
308 h->bytes_reserved = 0;
309 h->delayed_ref_updates = 0;
310 h->use_count = 1;
311 h->block_rsv = NULL;
312 h->orig_rsv = NULL;
313
314 smp_mb();
315 if (cur_trans->blocked && may_wait_transaction(root, type)) {
316 btrfs_commit_transaction(h, root);
317 goto again;
318 }
319
320 if (num_bytes) {
321 h->block_rsv = &root->fs_info->trans_block_rsv;
322 h->bytes_reserved = num_bytes;
323 }
324
325got_it:
326 btrfs_record_root_in_trans(h, root);
327
328 if (!current->journal_info && type != TRANS_USERSPACE)
329 current->journal_info = h;
330 return h;
331}
332
333struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
334 int num_items)
335{
336 return start_transaction(root, num_items, TRANS_START);
337}
338struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
339{
340 return start_transaction(root, 0, TRANS_JOIN);
341}
342
343struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
344{
345 return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
346}
347
348struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
349{
350 return start_transaction(root, 0, TRANS_USERSPACE);
351}
352
353/* wait for a transaction commit to be fully complete */
354static noinline void wait_for_commit(struct btrfs_root *root,
355 struct btrfs_transaction *commit)
356{
357 wait_event(commit->commit_wait, commit->commit_done);
358}
359
360int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
361{
362 struct btrfs_transaction *cur_trans = NULL, *t;
363 int ret;
364
365 ret = 0;
366 if (transid) {
367 if (transid <= root->fs_info->last_trans_committed)
368 goto out;
369
370 /* find specified transaction */
371 spin_lock(&root->fs_info->trans_lock);
372 list_for_each_entry(t, &root->fs_info->trans_list, list) {
373 if (t->transid == transid) {
374 cur_trans = t;
375 atomic_inc(&cur_trans->use_count);
376 break;
377 }
378 if (t->transid > transid)
379 break;
380 }
381 spin_unlock(&root->fs_info->trans_lock);
382 ret = -EINVAL;
383 if (!cur_trans)
384 goto out; /* bad transid */
385 } else {
386 /* find newest transaction that is committing | committed */
387 spin_lock(&root->fs_info->trans_lock);
388 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
389 list) {
390 if (t->in_commit) {
391 if (t->commit_done)
392 break;
393 cur_trans = t;
394 atomic_inc(&cur_trans->use_count);
395 break;
396 }
397 }
398 spin_unlock(&root->fs_info->trans_lock);
399 if (!cur_trans)
400 goto out; /* nothing committing|committed */
401 }
402
403 wait_for_commit(root, cur_trans);
404
405 put_transaction(cur_trans);
406 ret = 0;
407out:
408 return ret;
409}
410
411void btrfs_throttle(struct btrfs_root *root)
412{
413 if (!atomic_read(&root->fs_info->open_ioctl_trans))
414 wait_current_trans(root);
415}
416
417static int should_end_transaction(struct btrfs_trans_handle *trans,
418 struct btrfs_root *root)
419{
420 int ret;
421 ret = btrfs_block_rsv_check(trans, root,
422 &root->fs_info->global_block_rsv, 0, 5);
423 return ret ? 1 : 0;
424}
425
426int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
427 struct btrfs_root *root)
428{
429 struct btrfs_transaction *cur_trans = trans->transaction;
430 int updates;
431
432 smp_mb();
433 if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
434 return 1;
435
436 updates = trans->delayed_ref_updates;
437 trans->delayed_ref_updates = 0;
438 if (updates)
439 btrfs_run_delayed_refs(trans, root, updates);
440
441 return should_end_transaction(trans, root);
442}
443
444static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
445 struct btrfs_root *root, int throttle, int lock)
446{
447 struct btrfs_transaction *cur_trans = trans->transaction;
448 struct btrfs_fs_info *info = root->fs_info;
449 int count = 0;
450
451 if (--trans->use_count) {
452 trans->block_rsv = trans->orig_rsv;
453 return 0;
454 }
455
456 while (count < 4) {
457 unsigned long cur = trans->delayed_ref_updates;
458 trans->delayed_ref_updates = 0;
459 if (cur &&
460 trans->transaction->delayed_refs.num_heads_ready > 64) {
461 trans->delayed_ref_updates = 0;
462
463 /*
464 * do a full flush if the transaction is trying
465 * to close
466 */
467 if (trans->transaction->delayed_refs.flushing)
468 cur = 0;
469 btrfs_run_delayed_refs(trans, root, cur);
470 } else {
471 break;
472 }
473 count++;
474 }
475
476 btrfs_trans_release_metadata(trans, root);
477
478 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
479 should_end_transaction(trans, root)) {
480 trans->transaction->blocked = 1;
481 smp_wmb();
482 }
483
484 if (lock && cur_trans->blocked && !cur_trans->in_commit) {
485 if (throttle) {
486 /*
487 * We may race with somebody else here so end up having
488 * to call end_transaction on ourselves again, so inc
489 * our use_count.
490 */
491 trans->use_count++;
492 return btrfs_commit_transaction(trans, root);
493 } else {
494 wake_up_process(info->transaction_kthread);
495 }
496 }
497
498 WARN_ON(cur_trans != info->running_transaction);
499 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
500 atomic_dec(&cur_trans->num_writers);
501
502 smp_mb();
503 if (waitqueue_active(&cur_trans->writer_wait))
504 wake_up(&cur_trans->writer_wait);
505 put_transaction(cur_trans);
506
507 if (current->journal_info == trans)
508 current->journal_info = NULL;
509 memset(trans, 0, sizeof(*trans));
510 kmem_cache_free(btrfs_trans_handle_cachep, trans);
511
512 if (throttle)
513 btrfs_run_delayed_iputs(root);
514
515 return 0;
516}
517
518int btrfs_end_transaction(struct btrfs_trans_handle *trans,
519 struct btrfs_root *root)
520{
521 int ret;
522
523 ret = __btrfs_end_transaction(trans, root, 0, 1);
524 if (ret)
525 return ret;
526 return 0;
527}
528
529int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
530 struct btrfs_root *root)
531{
532 int ret;
533
534 ret = __btrfs_end_transaction(trans, root, 1, 1);
535 if (ret)
536 return ret;
537 return 0;
538}
539
540int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
541 struct btrfs_root *root)
542{
543 int ret;
544
545 ret = __btrfs_end_transaction(trans, root, 0, 0);
546 if (ret)
547 return ret;
548 return 0;
549}
550
551int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
552 struct btrfs_root *root)
553{
554 return __btrfs_end_transaction(trans, root, 1, 1);
555}
556
557/*
558 * when btree blocks are allocated, they have some corresponding bits set for
559 * them in one of two extent_io trees. This is used to make sure all of
560 * those extents are sent to disk but does not wait on them
561 */
562int btrfs_write_marked_extents(struct btrfs_root *root,
563 struct extent_io_tree *dirty_pages, int mark)
564{
565 int ret;
566 int err = 0;
567 int werr = 0;
568 struct page *page;
569 struct inode *btree_inode = root->fs_info->btree_inode;
570 u64 start = 0;
571 u64 end;
572 unsigned long index;
573
574 while (1) {
575 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
576 mark);
577 if (ret)
578 break;
579 while (start <= end) {
580 cond_resched();
581
582 index = start >> PAGE_CACHE_SHIFT;
583 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
584 page = find_get_page(btree_inode->i_mapping, index);
585 if (!page)
586 continue;
587
588 btree_lock_page_hook(page);
589 if (!page->mapping) {
590 unlock_page(page);
591 page_cache_release(page);
592 continue;
593 }
594
595 if (PageWriteback(page)) {
596 if (PageDirty(page))
597 wait_on_page_writeback(page);
598 else {
599 unlock_page(page);
600 page_cache_release(page);
601 continue;
602 }
603 }
604 err = write_one_page(page, 0);
605 if (err)
606 werr = err;
607 page_cache_release(page);
608 }
609 }
610 if (err)
611 werr = err;
612 return werr;
613}
614
615/*
616 * when btree blocks are allocated, they have some corresponding bits set for
617 * them in one of two extent_io trees. This is used to make sure all of
618 * those extents are on disk for transaction or log commit. We wait
619 * on all the pages and clear them from the dirty pages state tree
620 */
621int btrfs_wait_marked_extents(struct btrfs_root *root,
622 struct extent_io_tree *dirty_pages, int mark)
623{
624 int ret;
625 int err = 0;
626 int werr = 0;
627 struct page *page;
628 struct inode *btree_inode = root->fs_info->btree_inode;
629 u64 start = 0;
630 u64 end;
631 unsigned long index;
632
633 while (1) {
634 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
635 mark);
636 if (ret)
637 break;
638
639 clear_extent_bits(dirty_pages, start, end, mark, GFP_NOFS);
640 while (start <= end) {
641 index = start >> PAGE_CACHE_SHIFT;
642 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
643 page = find_get_page(btree_inode->i_mapping, index);
644 if (!page)
645 continue;
646 if (PageDirty(page)) {
647 btree_lock_page_hook(page);
648 wait_on_page_writeback(page);
649 err = write_one_page(page, 0);
650 if (err)
651 werr = err;
652 }
653 wait_on_page_writeback(page);
654 page_cache_release(page);
655 cond_resched();
656 }
657 }
658 if (err)
659 werr = err;
660 return werr;
661}
662
663/*
664 * when btree blocks are allocated, they have some corresponding bits set for
665 * them in one of two extent_io trees. This is used to make sure all of
666 * those extents are on disk for transaction or log commit
667 */
668int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
669 struct extent_io_tree *dirty_pages, int mark)
670{
671 int ret;
672 int ret2;
673
674 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
675 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
676 return ret || ret2;
677}
678
679int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
680 struct btrfs_root *root)
681{
682 if (!trans || !trans->transaction) {
683 struct inode *btree_inode;
684 btree_inode = root->fs_info->btree_inode;
685 return filemap_write_and_wait(btree_inode->i_mapping);
686 }
687 return btrfs_write_and_wait_marked_extents(root,
688 &trans->transaction->dirty_pages,
689 EXTENT_DIRTY);
690}
691
692/*
693 * this is used to update the root pointer in the tree of tree roots.
694 *
695 * But, in the case of the extent allocation tree, updating the root
696 * pointer may allocate blocks which may change the root of the extent
697 * allocation tree.
698 *
699 * So, this loops and repeats and makes sure the cowonly root didn't
700 * change while the root pointer was being updated in the metadata.
701 */
702static int update_cowonly_root(struct btrfs_trans_handle *trans,
703 struct btrfs_root *root)
704{
705 int ret;
706 u64 old_root_bytenr;
707 u64 old_root_used;
708 struct btrfs_root *tree_root = root->fs_info->tree_root;
709
710 old_root_used = btrfs_root_used(&root->root_item);
711 btrfs_write_dirty_block_groups(trans, root);
712
713 while (1) {
714 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
715 if (old_root_bytenr == root->node->start &&
716 old_root_used == btrfs_root_used(&root->root_item))
717 break;
718
719 btrfs_set_root_node(&root->root_item, root->node);
720 ret = btrfs_update_root(trans, tree_root,
721 &root->root_key,
722 &root->root_item);
723 BUG_ON(ret);
724
725 old_root_used = btrfs_root_used(&root->root_item);
726 ret = btrfs_write_dirty_block_groups(trans, root);
727 BUG_ON(ret);
728 }
729
730 if (root != root->fs_info->extent_root)
731 switch_commit_root(root);
732
733 return 0;
734}
735
736/*
737 * update all the cowonly tree roots on disk
738 */
739static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
740 struct btrfs_root *root)
741{
742 struct btrfs_fs_info *fs_info = root->fs_info;
743 struct list_head *next;
744 struct extent_buffer *eb;
745 int ret;
746
747 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
748 BUG_ON(ret);
749
750 eb = btrfs_lock_root_node(fs_info->tree_root);
751 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
752 btrfs_tree_unlock(eb);
753 free_extent_buffer(eb);
754
755 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
756 BUG_ON(ret);
757
758 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
759 next = fs_info->dirty_cowonly_roots.next;
760 list_del_init(next);
761 root = list_entry(next, struct btrfs_root, dirty_list);
762
763 update_cowonly_root(trans, root);
764 }
765
766 down_write(&fs_info->extent_commit_sem);
767 switch_commit_root(fs_info->extent_root);
768 up_write(&fs_info->extent_commit_sem);
769
770 return 0;
771}
772
773/*
774 * dead roots are old snapshots that need to be deleted. This allocates
775 * a dirty root struct and adds it into the list of dead roots that need to
776 * be deleted
777 */
778int btrfs_add_dead_root(struct btrfs_root *root)
779{
780 spin_lock(&root->fs_info->trans_lock);
781 list_add(&root->root_list, &root->fs_info->dead_roots);
782 spin_unlock(&root->fs_info->trans_lock);
783 return 0;
784}
785
786/*
787 * update all the cowonly tree roots on disk
788 */
789static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
790 struct btrfs_root *root)
791{
792 struct btrfs_root *gang[8];
793 struct btrfs_fs_info *fs_info = root->fs_info;
794 int i;
795 int ret;
796 int err = 0;
797
798 spin_lock(&fs_info->fs_roots_radix_lock);
799 while (1) {
800 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
801 (void **)gang, 0,
802 ARRAY_SIZE(gang),
803 BTRFS_ROOT_TRANS_TAG);
804 if (ret == 0)
805 break;
806 for (i = 0; i < ret; i++) {
807 root = gang[i];
808 radix_tree_tag_clear(&fs_info->fs_roots_radix,
809 (unsigned long)root->root_key.objectid,
810 BTRFS_ROOT_TRANS_TAG);
811 spin_unlock(&fs_info->fs_roots_radix_lock);
812
813 btrfs_free_log(trans, root);
814 btrfs_update_reloc_root(trans, root);
815 btrfs_orphan_commit_root(trans, root);
816
817 btrfs_save_ino_cache(root, trans);
818
819 if (root->commit_root != root->node) {
820 mutex_lock(&root->fs_commit_mutex);
821 switch_commit_root(root);
822 btrfs_unpin_free_ino(root);
823 mutex_unlock(&root->fs_commit_mutex);
824
825 btrfs_set_root_node(&root->root_item,
826 root->node);
827 }
828
829 err = btrfs_update_root(trans, fs_info->tree_root,
830 &root->root_key,
831 &root->root_item);
832 spin_lock(&fs_info->fs_roots_radix_lock);
833 if (err)
834 break;
835 }
836 }
837 spin_unlock(&fs_info->fs_roots_radix_lock);
838 return err;
839}
840
841/*
842 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
843 * otherwise every leaf in the btree is read and defragged.
844 */
845int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
846{
847 struct btrfs_fs_info *info = root->fs_info;
848 struct btrfs_trans_handle *trans;
849 int ret;
850 unsigned long nr;
851
852 if (xchg(&root->defrag_running, 1))
853 return 0;
854
855 while (1) {
856 trans = btrfs_start_transaction(root, 0);
857 if (IS_ERR(trans))
858 return PTR_ERR(trans);
859
860 ret = btrfs_defrag_leaves(trans, root, cacheonly);
861
862 nr = trans->blocks_used;
863 btrfs_end_transaction(trans, root);
864 btrfs_btree_balance_dirty(info->tree_root, nr);
865 cond_resched();
866
867 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
868 break;
869 }
870 root->defrag_running = 0;
871 return ret;
872}
873
874/*
875 * new snapshots need to be created at a very specific time in the
876 * transaction commit. This does the actual creation
877 */
878static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
879 struct btrfs_fs_info *fs_info,
880 struct btrfs_pending_snapshot *pending)
881{
882 struct btrfs_key key;
883 struct btrfs_root_item *new_root_item;
884 struct btrfs_root *tree_root = fs_info->tree_root;
885 struct btrfs_root *root = pending->root;
886 struct btrfs_root *parent_root;
887 struct btrfs_block_rsv *rsv;
888 struct inode *parent_inode;
889 struct dentry *parent;
890 struct dentry *dentry;
891 struct extent_buffer *tmp;
892 struct extent_buffer *old;
893 int ret;
894 u64 to_reserve = 0;
895 u64 index = 0;
896 u64 objectid;
897 u64 root_flags;
898
899 rsv = trans->block_rsv;
900
901 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
902 if (!new_root_item) {
903 pending->error = -ENOMEM;
904 goto fail;
905 }
906
907 ret = btrfs_find_free_objectid(tree_root, &objectid);
908 if (ret) {
909 pending->error = ret;
910 goto fail;
911 }
912
913 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
914 btrfs_orphan_pre_snapshot(trans, pending, &to_reserve);
915
916 if (to_reserve > 0) {
917 ret = btrfs_block_rsv_add(trans, root, &pending->block_rsv,
918 to_reserve);
919 if (ret) {
920 pending->error = ret;
921 goto fail;
922 }
923 }
924
925 key.objectid = objectid;
926 key.offset = (u64)-1;
927 key.type = BTRFS_ROOT_ITEM_KEY;
928
929 trans->block_rsv = &pending->block_rsv;
930
931 dentry = pending->dentry;
932 parent = dget_parent(dentry);
933 parent_inode = parent->d_inode;
934 parent_root = BTRFS_I(parent_inode)->root;
935 record_root_in_trans(trans, parent_root);
936
937 /*
938 * insert the directory item
939 */
940 ret = btrfs_set_inode_index(parent_inode, &index);
941 BUG_ON(ret);
942 ret = btrfs_insert_dir_item(trans, parent_root,
943 dentry->d_name.name, dentry->d_name.len,
944 parent_inode, &key,
945 BTRFS_FT_DIR, index);
946 BUG_ON(ret);
947
948 btrfs_i_size_write(parent_inode, parent_inode->i_size +
949 dentry->d_name.len * 2);
950 ret = btrfs_update_inode(trans, parent_root, parent_inode);
951 BUG_ON(ret);
952
953 /*
954 * pull in the delayed directory update
955 * and the delayed inode item
956 * otherwise we corrupt the FS during
957 * snapshot
958 */
959 ret = btrfs_run_delayed_items(trans, root);
960 BUG_ON(ret);
961
962 record_root_in_trans(trans, root);
963 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
964 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
965 btrfs_check_and_init_root_item(new_root_item);
966
967 root_flags = btrfs_root_flags(new_root_item);
968 if (pending->readonly)
969 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
970 else
971 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
972 btrfs_set_root_flags(new_root_item, root_flags);
973
974 old = btrfs_lock_root_node(root);
975 btrfs_cow_block(trans, root, old, NULL, 0, &old);
976 btrfs_set_lock_blocking(old);
977
978 btrfs_copy_root(trans, root, old, &tmp, objectid);
979 btrfs_tree_unlock(old);
980 free_extent_buffer(old);
981
982 btrfs_set_root_node(new_root_item, tmp);
983 /* record when the snapshot was created in key.offset */
984 key.offset = trans->transid;
985 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
986 btrfs_tree_unlock(tmp);
987 free_extent_buffer(tmp);
988 BUG_ON(ret);
989
990 /*
991 * insert root back/forward references
992 */
993 ret = btrfs_add_root_ref(trans, tree_root, objectid,
994 parent_root->root_key.objectid,
995 btrfs_ino(parent_inode), index,
996 dentry->d_name.name, dentry->d_name.len);
997 BUG_ON(ret);
998 dput(parent);
999
1000 key.offset = (u64)-1;
1001 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1002 BUG_ON(IS_ERR(pending->snap));
1003
1004 btrfs_reloc_post_snapshot(trans, pending);
1005 btrfs_orphan_post_snapshot(trans, pending);
1006fail:
1007 kfree(new_root_item);
1008 trans->block_rsv = rsv;
1009 btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1010 return 0;
1011}
1012
1013/*
1014 * create all the snapshots we've scheduled for creation
1015 */
1016static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1017 struct btrfs_fs_info *fs_info)
1018{
1019 struct btrfs_pending_snapshot *pending;
1020 struct list_head *head = &trans->transaction->pending_snapshots;
1021 int ret;
1022
1023 list_for_each_entry(pending, head, list) {
1024 ret = create_pending_snapshot(trans, fs_info, pending);
1025 BUG_ON(ret);
1026 }
1027 return 0;
1028}
1029
1030static void update_super_roots(struct btrfs_root *root)
1031{
1032 struct btrfs_root_item *root_item;
1033 struct btrfs_super_block *super;
1034
1035 super = &root->fs_info->super_copy;
1036
1037 root_item = &root->fs_info->chunk_root->root_item;
1038 super->chunk_root = root_item->bytenr;
1039 super->chunk_root_generation = root_item->generation;
1040 super->chunk_root_level = root_item->level;
1041
1042 root_item = &root->fs_info->tree_root->root_item;
1043 super->root = root_item->bytenr;
1044 super->generation = root_item->generation;
1045 super->root_level = root_item->level;
1046 if (super->cache_generation != 0 || btrfs_test_opt(root, SPACE_CACHE))
1047 super->cache_generation = root_item->generation;
1048}
1049
1050int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1051{
1052 int ret = 0;
1053 spin_lock(&info->trans_lock);
1054 if (info->running_transaction)
1055 ret = info->running_transaction->in_commit;
1056 spin_unlock(&info->trans_lock);
1057 return ret;
1058}
1059
1060int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1061{
1062 int ret = 0;
1063 spin_lock(&info->trans_lock);
1064 if (info->running_transaction)
1065 ret = info->running_transaction->blocked;
1066 spin_unlock(&info->trans_lock);
1067 return ret;
1068}
1069
1070/*
1071 * wait for the current transaction commit to start and block subsequent
1072 * transaction joins
1073 */
1074static void wait_current_trans_commit_start(struct btrfs_root *root,
1075 struct btrfs_transaction *trans)
1076{
1077 wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
1078}
1079
1080/*
1081 * wait for the current transaction to start and then become unblocked.
1082 * caller holds ref.
1083 */
1084static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1085 struct btrfs_transaction *trans)
1086{
1087 wait_event(root->fs_info->transaction_wait,
1088 trans->commit_done || (trans->in_commit && !trans->blocked));
1089}
1090
1091/*
1092 * commit transactions asynchronously. once btrfs_commit_transaction_async
1093 * returns, any subsequent transaction will not be allowed to join.
1094 */
1095struct btrfs_async_commit {
1096 struct btrfs_trans_handle *newtrans;
1097 struct btrfs_root *root;
1098 struct delayed_work work;
1099};
1100
1101static void do_async_commit(struct work_struct *work)
1102{
1103 struct btrfs_async_commit *ac =
1104 container_of(work, struct btrfs_async_commit, work.work);
1105
1106 btrfs_commit_transaction(ac->newtrans, ac->root);
1107 kfree(ac);
1108}
1109
1110int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1111 struct btrfs_root *root,
1112 int wait_for_unblock)
1113{
1114 struct btrfs_async_commit *ac;
1115 struct btrfs_transaction *cur_trans;
1116
1117 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1118 if (!ac)
1119 return -ENOMEM;
1120
1121 INIT_DELAYED_WORK(&ac->work, do_async_commit);
1122 ac->root = root;
1123 ac->newtrans = btrfs_join_transaction(root);
1124 if (IS_ERR(ac->newtrans)) {
1125 int err = PTR_ERR(ac->newtrans);
1126 kfree(ac);
1127 return err;
1128 }
1129
1130 /* take transaction reference */
1131 cur_trans = trans->transaction;
1132 atomic_inc(&cur_trans->use_count);
1133
1134 btrfs_end_transaction(trans, root);
1135 schedule_delayed_work(&ac->work, 0);
1136
1137 /* wait for transaction to start and unblock */
1138 if (wait_for_unblock)
1139 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1140 else
1141 wait_current_trans_commit_start(root, cur_trans);
1142
1143 if (current->journal_info == trans)
1144 current->journal_info = NULL;
1145
1146 put_transaction(cur_trans);
1147 return 0;
1148}
1149
1150/*
1151 * btrfs_transaction state sequence:
1152 * in_commit = 0, blocked = 0 (initial)
1153 * in_commit = 1, blocked = 1
1154 * blocked = 0
1155 * commit_done = 1
1156 */
1157int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1158 struct btrfs_root *root)
1159{
1160 unsigned long joined = 0;
1161 struct btrfs_transaction *cur_trans;
1162 struct btrfs_transaction *prev_trans = NULL;
1163 DEFINE_WAIT(wait);
1164 int ret;
1165 int should_grow = 0;
1166 unsigned long now = get_seconds();
1167 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1168
1169 btrfs_run_ordered_operations(root, 0);
1170
1171 /* make a pass through all the delayed refs we have so far
1172 * any runnings procs may add more while we are here
1173 */
1174 ret = btrfs_run_delayed_refs(trans, root, 0);
1175 BUG_ON(ret);
1176
1177 btrfs_trans_release_metadata(trans, root);
1178
1179 cur_trans = trans->transaction;
1180 /*
1181 * set the flushing flag so procs in this transaction have to
1182 * start sending their work down.
1183 */
1184 cur_trans->delayed_refs.flushing = 1;
1185
1186 ret = btrfs_run_delayed_refs(trans, root, 0);
1187 BUG_ON(ret);
1188
1189 spin_lock(&cur_trans->commit_lock);
1190 if (cur_trans->in_commit) {
1191 spin_unlock(&cur_trans->commit_lock);
1192 atomic_inc(&cur_trans->use_count);
1193 btrfs_end_transaction(trans, root);
1194
1195 wait_for_commit(root, cur_trans);
1196
1197 put_transaction(cur_trans);
1198
1199 return 0;
1200 }
1201
1202 trans->transaction->in_commit = 1;
1203 trans->transaction->blocked = 1;
1204 spin_unlock(&cur_trans->commit_lock);
1205 wake_up(&root->fs_info->transaction_blocked_wait);
1206
1207 spin_lock(&root->fs_info->trans_lock);
1208 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1209 prev_trans = list_entry(cur_trans->list.prev,
1210 struct btrfs_transaction, list);
1211 if (!prev_trans->commit_done) {
1212 atomic_inc(&prev_trans->use_count);
1213 spin_unlock(&root->fs_info->trans_lock);
1214
1215 wait_for_commit(root, prev_trans);
1216
1217 put_transaction(prev_trans);
1218 } else {
1219 spin_unlock(&root->fs_info->trans_lock);
1220 }
1221 } else {
1222 spin_unlock(&root->fs_info->trans_lock);
1223 }
1224
1225 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1226 should_grow = 1;
1227
1228 do {
1229 int snap_pending = 0;
1230
1231 joined = cur_trans->num_joined;
1232 if (!list_empty(&trans->transaction->pending_snapshots))
1233 snap_pending = 1;
1234
1235 WARN_ON(cur_trans != trans->transaction);
1236
1237 if (flush_on_commit || snap_pending) {
1238 btrfs_start_delalloc_inodes(root, 1);
1239 ret = btrfs_wait_ordered_extents(root, 0, 1);
1240 BUG_ON(ret);
1241 }
1242
1243 ret = btrfs_run_delayed_items(trans, root);
1244 BUG_ON(ret);
1245
1246 /*
1247 * rename don't use btrfs_join_transaction, so, once we
1248 * set the transaction to blocked above, we aren't going
1249 * to get any new ordered operations. We can safely run
1250 * it here and no for sure that nothing new will be added
1251 * to the list
1252 */
1253 btrfs_run_ordered_operations(root, 1);
1254
1255 prepare_to_wait(&cur_trans->writer_wait, &wait,
1256 TASK_UNINTERRUPTIBLE);
1257
1258 if (atomic_read(&cur_trans->num_writers) > 1)
1259 schedule_timeout(MAX_SCHEDULE_TIMEOUT);
1260 else if (should_grow)
1261 schedule_timeout(1);
1262
1263 finish_wait(&cur_trans->writer_wait, &wait);
1264 } while (atomic_read(&cur_trans->num_writers) > 1 ||
1265 (should_grow && cur_trans->num_joined != joined));
1266
1267 /*
1268 * Ok now we need to make sure to block out any other joins while we
1269 * commit the transaction. We could have started a join before setting
1270 * no_join so make sure to wait for num_writers to == 1 again.
1271 */
1272 spin_lock(&root->fs_info->trans_lock);
1273 root->fs_info->trans_no_join = 1;
1274 spin_unlock(&root->fs_info->trans_lock);
1275 wait_event(cur_trans->writer_wait,
1276 atomic_read(&cur_trans->num_writers) == 1);
1277
1278 /*
1279 * the reloc mutex makes sure that we stop
1280 * the balancing code from coming in and moving
1281 * extents around in the middle of the commit
1282 */
1283 mutex_lock(&root->fs_info->reloc_mutex);
1284
1285 ret = btrfs_run_delayed_items(trans, root);
1286 BUG_ON(ret);
1287
1288 ret = create_pending_snapshots(trans, root->fs_info);
1289 BUG_ON(ret);
1290
1291 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1292 BUG_ON(ret);
1293
1294 /*
1295 * make sure none of the code above managed to slip in a
1296 * delayed item
1297 */
1298 btrfs_assert_delayed_root_empty(root);
1299
1300 WARN_ON(cur_trans != trans->transaction);
1301
1302 btrfs_scrub_pause(root);
1303 /* btrfs_commit_tree_roots is responsible for getting the
1304 * various roots consistent with each other. Every pointer
1305 * in the tree of tree roots has to point to the most up to date
1306 * root for every subvolume and other tree. So, we have to keep
1307 * the tree logging code from jumping in and changing any
1308 * of the trees.
1309 *
1310 * At this point in the commit, there can't be any tree-log
1311 * writers, but a little lower down we drop the trans mutex
1312 * and let new people in. By holding the tree_log_mutex
1313 * from now until after the super is written, we avoid races
1314 * with the tree-log code.
1315 */
1316 mutex_lock(&root->fs_info->tree_log_mutex);
1317
1318 ret = commit_fs_roots(trans, root);
1319 BUG_ON(ret);
1320
1321 /* commit_fs_roots gets rid of all the tree log roots, it is now
1322 * safe to free the root of tree log roots
1323 */
1324 btrfs_free_log_root_tree(trans, root->fs_info);
1325
1326 ret = commit_cowonly_roots(trans, root);
1327 BUG_ON(ret);
1328
1329 btrfs_prepare_extent_commit(trans, root);
1330
1331 cur_trans = root->fs_info->running_transaction;
1332
1333 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1334 root->fs_info->tree_root->node);
1335 switch_commit_root(root->fs_info->tree_root);
1336
1337 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1338 root->fs_info->chunk_root->node);
1339 switch_commit_root(root->fs_info->chunk_root);
1340
1341 update_super_roots(root);
1342
1343 if (!root->fs_info->log_root_recovering) {
1344 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1345 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1346 }
1347
1348 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1349 sizeof(root->fs_info->super_copy));
1350
1351 trans->transaction->blocked = 0;
1352 spin_lock(&root->fs_info->trans_lock);
1353 root->fs_info->running_transaction = NULL;
1354 root->fs_info->trans_no_join = 0;
1355 spin_unlock(&root->fs_info->trans_lock);
1356 mutex_unlock(&root->fs_info->reloc_mutex);
1357
1358 wake_up(&root->fs_info->transaction_wait);
1359
1360 ret = btrfs_write_and_wait_transaction(trans, root);
1361 BUG_ON(ret);
1362 write_ctree_super(trans, root, 0);
1363
1364 /*
1365 * the super is written, we can safely allow the tree-loggers
1366 * to go about their business
1367 */
1368 mutex_unlock(&root->fs_info->tree_log_mutex);
1369
1370 btrfs_finish_extent_commit(trans, root);
1371
1372 cur_trans->commit_done = 1;
1373
1374 root->fs_info->last_trans_committed = cur_trans->transid;
1375
1376 wake_up(&cur_trans->commit_wait);
1377
1378 spin_lock(&root->fs_info->trans_lock);
1379 list_del_init(&cur_trans->list);
1380 spin_unlock(&root->fs_info->trans_lock);
1381
1382 put_transaction(cur_trans);
1383 put_transaction(cur_trans);
1384
1385 trace_btrfs_transaction_commit(root);
1386
1387 btrfs_scrub_continue(root);
1388
1389 if (current->journal_info == trans)
1390 current->journal_info = NULL;
1391
1392 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1393
1394 if (current != root->fs_info->transaction_kthread)
1395 btrfs_run_delayed_iputs(root);
1396
1397 return ret;
1398}
1399
1400/*
1401 * interface function to delete all the snapshots we have scheduled for deletion
1402 */
1403int btrfs_clean_old_snapshots(struct btrfs_root *root)
1404{
1405 LIST_HEAD(list);
1406 struct btrfs_fs_info *fs_info = root->fs_info;
1407
1408 spin_lock(&fs_info->trans_lock);
1409 list_splice_init(&fs_info->dead_roots, &list);
1410 spin_unlock(&fs_info->trans_lock);
1411
1412 while (!list_empty(&list)) {
1413 root = list_entry(list.next, struct btrfs_root, root_list);
1414 list_del(&root->root_list);
1415
1416 btrfs_kill_all_delayed_nodes(root);
1417
1418 if (btrfs_header_backref_rev(root->node) <
1419 BTRFS_MIXED_BACKREF_REV)
1420 btrfs_drop_snapshot(root, NULL, 0);
1421 else
1422 btrfs_drop_snapshot(root, NULL, 1);
1423 }
1424 return 0;
1425}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
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.
7 *
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.
12 *
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.
17 */
18
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"
31#include "volumes.h"
32
33#define BTRFS_ROOT_TRANS_TAG 0
34
35void put_transaction(struct btrfs_transaction *transaction)
36{
37 WARN_ON(atomic_read(&transaction->use_count) == 0);
38 if (atomic_dec_and_test(&transaction->use_count)) {
39 BUG_ON(!list_empty(&transaction->list));
40 WARN_ON(transaction->delayed_refs.root.rb_node);
41 WARN_ON(!list_empty(&transaction->delayed_refs.seq_head));
42 memset(transaction, 0, sizeof(*transaction));
43 kmem_cache_free(btrfs_transaction_cachep, transaction);
44 }
45}
46
47static noinline void switch_commit_root(struct btrfs_root *root)
48{
49 free_extent_buffer(root->commit_root);
50 root->commit_root = btrfs_root_node(root);
51}
52
53/*
54 * either allocate a new transaction or hop into the existing one
55 */
56static noinline int join_transaction(struct btrfs_root *root, int nofail)
57{
58 struct btrfs_transaction *cur_trans;
59 struct btrfs_fs_info *fs_info = root->fs_info;
60
61 spin_lock(&fs_info->trans_lock);
62loop:
63 /* The file system has been taken offline. No new transactions. */
64 if (fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
65 spin_unlock(&fs_info->trans_lock);
66 return -EROFS;
67 }
68
69 if (fs_info->trans_no_join) {
70 if (!nofail) {
71 spin_unlock(&fs_info->trans_lock);
72 return -EBUSY;
73 }
74 }
75
76 cur_trans = fs_info->running_transaction;
77 if (cur_trans) {
78 if (cur_trans->aborted) {
79 spin_unlock(&fs_info->trans_lock);
80 return cur_trans->aborted;
81 }
82 atomic_inc(&cur_trans->use_count);
83 atomic_inc(&cur_trans->num_writers);
84 cur_trans->num_joined++;
85 spin_unlock(&fs_info->trans_lock);
86 return 0;
87 }
88 spin_unlock(&fs_info->trans_lock);
89
90 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
91 if (!cur_trans)
92 return -ENOMEM;
93
94 spin_lock(&fs_info->trans_lock);
95 if (fs_info->running_transaction) {
96 /*
97 * someone started a transaction after we unlocked. Make sure
98 * to redo the trans_no_join checks above
99 */
100 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
101 cur_trans = fs_info->running_transaction;
102 goto loop;
103 } else if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
104 spin_unlock(&root->fs_info->trans_lock);
105 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
106 return -EROFS;
107 }
108
109 atomic_set(&cur_trans->num_writers, 1);
110 cur_trans->num_joined = 0;
111 init_waitqueue_head(&cur_trans->writer_wait);
112 init_waitqueue_head(&cur_trans->commit_wait);
113 cur_trans->in_commit = 0;
114 cur_trans->blocked = 0;
115 /*
116 * One for this trans handle, one so it will live on until we
117 * commit the transaction.
118 */
119 atomic_set(&cur_trans->use_count, 2);
120 cur_trans->commit_done = 0;
121 cur_trans->start_time = get_seconds();
122
123 cur_trans->delayed_refs.root = RB_ROOT;
124 cur_trans->delayed_refs.num_entries = 0;
125 cur_trans->delayed_refs.num_heads_ready = 0;
126 cur_trans->delayed_refs.num_heads = 0;
127 cur_trans->delayed_refs.flushing = 0;
128 cur_trans->delayed_refs.run_delayed_start = 0;
129 cur_trans->delayed_refs.seq = 1;
130
131 /*
132 * although the tree mod log is per file system and not per transaction,
133 * the log must never go across transaction boundaries.
134 */
135 smp_mb();
136 if (!list_empty(&fs_info->tree_mod_seq_list)) {
137 printk(KERN_ERR "btrfs: tree_mod_seq_list not empty when "
138 "creating a fresh transaction\n");
139 WARN_ON(1);
140 }
141 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log)) {
142 printk(KERN_ERR "btrfs: tree_mod_log rb tree not empty when "
143 "creating a fresh transaction\n");
144 WARN_ON(1);
145 }
146 atomic_set(&fs_info->tree_mod_seq, 0);
147
148 init_waitqueue_head(&cur_trans->delayed_refs.seq_wait);
149 spin_lock_init(&cur_trans->commit_lock);
150 spin_lock_init(&cur_trans->delayed_refs.lock);
151 INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head);
152
153 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
154 list_add_tail(&cur_trans->list, &fs_info->trans_list);
155 extent_io_tree_init(&cur_trans->dirty_pages,
156 fs_info->btree_inode->i_mapping);
157 fs_info->generation++;
158 cur_trans->transid = fs_info->generation;
159 fs_info->running_transaction = cur_trans;
160 cur_trans->aborted = 0;
161 spin_unlock(&fs_info->trans_lock);
162
163 return 0;
164}
165
166/*
167 * this does all the record keeping required to make sure that a reference
168 * counted root is properly recorded in a given transaction. This is required
169 * to make sure the old root from before we joined the transaction is deleted
170 * when the transaction commits
171 */
172static int record_root_in_trans(struct btrfs_trans_handle *trans,
173 struct btrfs_root *root)
174{
175 if (root->ref_cows && root->last_trans < trans->transid) {
176 WARN_ON(root == root->fs_info->extent_root);
177 WARN_ON(root->commit_root != root->node);
178
179 /*
180 * see below for in_trans_setup usage rules
181 * we have the reloc mutex held now, so there
182 * is only one writer in this function
183 */
184 root->in_trans_setup = 1;
185
186 /* make sure readers find in_trans_setup before
187 * they find our root->last_trans update
188 */
189 smp_wmb();
190
191 spin_lock(&root->fs_info->fs_roots_radix_lock);
192 if (root->last_trans == trans->transid) {
193 spin_unlock(&root->fs_info->fs_roots_radix_lock);
194 return 0;
195 }
196 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
197 (unsigned long)root->root_key.objectid,
198 BTRFS_ROOT_TRANS_TAG);
199 spin_unlock(&root->fs_info->fs_roots_radix_lock);
200 root->last_trans = trans->transid;
201
202 /* this is pretty tricky. We don't want to
203 * take the relocation lock in btrfs_record_root_in_trans
204 * unless we're really doing the first setup for this root in
205 * this transaction.
206 *
207 * Normally we'd use root->last_trans as a flag to decide
208 * if we want to take the expensive mutex.
209 *
210 * But, we have to set root->last_trans before we
211 * init the relocation root, otherwise, we trip over warnings
212 * in ctree.c. The solution used here is to flag ourselves
213 * with root->in_trans_setup. When this is 1, we're still
214 * fixing up the reloc trees and everyone must wait.
215 *
216 * When this is zero, they can trust root->last_trans and fly
217 * through btrfs_record_root_in_trans without having to take the
218 * lock. smp_wmb() makes sure that all the writes above are
219 * done before we pop in the zero below
220 */
221 btrfs_init_reloc_root(trans, root);
222 smp_wmb();
223 root->in_trans_setup = 0;
224 }
225 return 0;
226}
227
228
229int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
230 struct btrfs_root *root)
231{
232 if (!root->ref_cows)
233 return 0;
234
235 /*
236 * see record_root_in_trans for comments about in_trans_setup usage
237 * and barriers
238 */
239 smp_rmb();
240 if (root->last_trans == trans->transid &&
241 !root->in_trans_setup)
242 return 0;
243
244 mutex_lock(&root->fs_info->reloc_mutex);
245 record_root_in_trans(trans, root);
246 mutex_unlock(&root->fs_info->reloc_mutex);
247
248 return 0;
249}
250
251/* wait for commit against the current transaction to become unblocked
252 * when this is done, it is safe to start a new transaction, but the current
253 * transaction might not be fully on disk.
254 */
255static void wait_current_trans(struct btrfs_root *root)
256{
257 struct btrfs_transaction *cur_trans;
258
259 spin_lock(&root->fs_info->trans_lock);
260 cur_trans = root->fs_info->running_transaction;
261 if (cur_trans && cur_trans->blocked) {
262 atomic_inc(&cur_trans->use_count);
263 spin_unlock(&root->fs_info->trans_lock);
264
265 wait_event(root->fs_info->transaction_wait,
266 !cur_trans->blocked);
267 put_transaction(cur_trans);
268 } else {
269 spin_unlock(&root->fs_info->trans_lock);
270 }
271}
272
273enum btrfs_trans_type {
274 TRANS_START,
275 TRANS_JOIN,
276 TRANS_USERSPACE,
277 TRANS_JOIN_NOLOCK,
278};
279
280static int may_wait_transaction(struct btrfs_root *root, int type)
281{
282 if (root->fs_info->log_root_recovering)
283 return 0;
284
285 if (type == TRANS_USERSPACE)
286 return 1;
287
288 if (type == TRANS_START &&
289 !atomic_read(&root->fs_info->open_ioctl_trans))
290 return 1;
291
292 return 0;
293}
294
295static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
296 u64 num_items, int type)
297{
298 struct btrfs_trans_handle *h;
299 struct btrfs_transaction *cur_trans;
300 u64 num_bytes = 0;
301 int ret;
302
303 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
304 return ERR_PTR(-EROFS);
305
306 if (current->journal_info) {
307 WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
308 h = current->journal_info;
309 h->use_count++;
310 h->orig_rsv = h->block_rsv;
311 h->block_rsv = NULL;
312 goto got_it;
313 }
314
315 /*
316 * Do the reservation before we join the transaction so we can do all
317 * the appropriate flushing if need be.
318 */
319 if (num_items > 0 && root != root->fs_info->chunk_root) {
320 num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
321 ret = btrfs_block_rsv_add(root,
322 &root->fs_info->trans_block_rsv,
323 num_bytes);
324 if (ret)
325 return ERR_PTR(ret);
326 }
327again:
328 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
329 if (!h)
330 return ERR_PTR(-ENOMEM);
331
332 if (may_wait_transaction(root, type))
333 wait_current_trans(root);
334
335 do {
336 ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
337 if (ret == -EBUSY)
338 wait_current_trans(root);
339 } while (ret == -EBUSY);
340
341 if (ret < 0) {
342 kmem_cache_free(btrfs_trans_handle_cachep, h);
343 return ERR_PTR(ret);
344 }
345
346 cur_trans = root->fs_info->running_transaction;
347
348 h->transid = cur_trans->transid;
349 h->transaction = cur_trans;
350 h->blocks_used = 0;
351 h->bytes_reserved = 0;
352 h->delayed_ref_updates = 0;
353 h->use_count = 1;
354 h->block_rsv = NULL;
355 h->orig_rsv = NULL;
356 h->aborted = 0;
357
358 smp_mb();
359 if (cur_trans->blocked && may_wait_transaction(root, type)) {
360 btrfs_commit_transaction(h, root);
361 goto again;
362 }
363
364 if (num_bytes) {
365 trace_btrfs_space_reservation(root->fs_info, "transaction",
366 h->transid, num_bytes, 1);
367 h->block_rsv = &root->fs_info->trans_block_rsv;
368 h->bytes_reserved = num_bytes;
369 }
370
371got_it:
372 btrfs_record_root_in_trans(h, root);
373
374 if (!current->journal_info && type != TRANS_USERSPACE)
375 current->journal_info = h;
376 return h;
377}
378
379struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
380 int num_items)
381{
382 return start_transaction(root, num_items, TRANS_START);
383}
384struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
385{
386 return start_transaction(root, 0, TRANS_JOIN);
387}
388
389struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
390{
391 return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
392}
393
394struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
395{
396 return start_transaction(root, 0, TRANS_USERSPACE);
397}
398
399/* wait for a transaction commit to be fully complete */
400static noinline void wait_for_commit(struct btrfs_root *root,
401 struct btrfs_transaction *commit)
402{
403 wait_event(commit->commit_wait, commit->commit_done);
404}
405
406int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
407{
408 struct btrfs_transaction *cur_trans = NULL, *t;
409 int ret;
410
411 ret = 0;
412 if (transid) {
413 if (transid <= root->fs_info->last_trans_committed)
414 goto out;
415
416 /* find specified transaction */
417 spin_lock(&root->fs_info->trans_lock);
418 list_for_each_entry(t, &root->fs_info->trans_list, list) {
419 if (t->transid == transid) {
420 cur_trans = t;
421 atomic_inc(&cur_trans->use_count);
422 break;
423 }
424 if (t->transid > transid)
425 break;
426 }
427 spin_unlock(&root->fs_info->trans_lock);
428 ret = -EINVAL;
429 if (!cur_trans)
430 goto out; /* bad transid */
431 } else {
432 /* find newest transaction that is committing | committed */
433 spin_lock(&root->fs_info->trans_lock);
434 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
435 list) {
436 if (t->in_commit) {
437 if (t->commit_done)
438 break;
439 cur_trans = t;
440 atomic_inc(&cur_trans->use_count);
441 break;
442 }
443 }
444 spin_unlock(&root->fs_info->trans_lock);
445 if (!cur_trans)
446 goto out; /* nothing committing|committed */
447 }
448
449 wait_for_commit(root, cur_trans);
450
451 put_transaction(cur_trans);
452 ret = 0;
453out:
454 return ret;
455}
456
457void btrfs_throttle(struct btrfs_root *root)
458{
459 if (!atomic_read(&root->fs_info->open_ioctl_trans))
460 wait_current_trans(root);
461}
462
463static int should_end_transaction(struct btrfs_trans_handle *trans,
464 struct btrfs_root *root)
465{
466 int ret;
467
468 ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
469 return ret ? 1 : 0;
470}
471
472int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
473 struct btrfs_root *root)
474{
475 struct btrfs_transaction *cur_trans = trans->transaction;
476 struct btrfs_block_rsv *rsv = trans->block_rsv;
477 int updates;
478 int err;
479
480 smp_mb();
481 if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
482 return 1;
483
484 /*
485 * We need to do this in case we're deleting csums so the global block
486 * rsv get's used instead of the csum block rsv.
487 */
488 trans->block_rsv = NULL;
489
490 updates = trans->delayed_ref_updates;
491 trans->delayed_ref_updates = 0;
492 if (updates) {
493 err = btrfs_run_delayed_refs(trans, root, updates);
494 if (err) /* Error code will also eval true */
495 return err;
496 }
497
498 trans->block_rsv = rsv;
499
500 return should_end_transaction(trans, root);
501}
502
503static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
504 struct btrfs_root *root, int throttle, int lock)
505{
506 struct btrfs_transaction *cur_trans = trans->transaction;
507 struct btrfs_fs_info *info = root->fs_info;
508 int count = 0;
509 int err = 0;
510
511 if (--trans->use_count) {
512 trans->block_rsv = trans->orig_rsv;
513 return 0;
514 }
515
516 btrfs_trans_release_metadata(trans, root);
517 trans->block_rsv = NULL;
518 while (count < 2) {
519 unsigned long cur = trans->delayed_ref_updates;
520 trans->delayed_ref_updates = 0;
521 if (cur &&
522 trans->transaction->delayed_refs.num_heads_ready > 64) {
523 trans->delayed_ref_updates = 0;
524 btrfs_run_delayed_refs(trans, root, cur);
525 } else {
526 break;
527 }
528 count++;
529 }
530
531 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
532 should_end_transaction(trans, root)) {
533 trans->transaction->blocked = 1;
534 smp_wmb();
535 }
536
537 if (lock && cur_trans->blocked && !cur_trans->in_commit) {
538 if (throttle) {
539 /*
540 * We may race with somebody else here so end up having
541 * to call end_transaction on ourselves again, so inc
542 * our use_count.
543 */
544 trans->use_count++;
545 return btrfs_commit_transaction(trans, root);
546 } else {
547 wake_up_process(info->transaction_kthread);
548 }
549 }
550
551 WARN_ON(cur_trans != info->running_transaction);
552 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
553 atomic_dec(&cur_trans->num_writers);
554
555 smp_mb();
556 if (waitqueue_active(&cur_trans->writer_wait))
557 wake_up(&cur_trans->writer_wait);
558 put_transaction(cur_trans);
559
560 if (current->journal_info == trans)
561 current->journal_info = NULL;
562
563 if (throttle)
564 btrfs_run_delayed_iputs(root);
565
566 if (trans->aborted ||
567 root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
568 err = -EIO;
569 }
570
571 memset(trans, 0, sizeof(*trans));
572 kmem_cache_free(btrfs_trans_handle_cachep, trans);
573 return err;
574}
575
576int btrfs_end_transaction(struct btrfs_trans_handle *trans,
577 struct btrfs_root *root)
578{
579 int ret;
580
581 ret = __btrfs_end_transaction(trans, root, 0, 1);
582 if (ret)
583 return ret;
584 return 0;
585}
586
587int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
588 struct btrfs_root *root)
589{
590 int ret;
591
592 ret = __btrfs_end_transaction(trans, root, 1, 1);
593 if (ret)
594 return ret;
595 return 0;
596}
597
598int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
599 struct btrfs_root *root)
600{
601 int ret;
602
603 ret = __btrfs_end_transaction(trans, root, 0, 0);
604 if (ret)
605 return ret;
606 return 0;
607}
608
609int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
610 struct btrfs_root *root)
611{
612 return __btrfs_end_transaction(trans, root, 1, 1);
613}
614
615/*
616 * when btree blocks are allocated, they have some corresponding bits set for
617 * them in one of two extent_io trees. This is used to make sure all of
618 * those extents are sent to disk but does not wait on them
619 */
620int btrfs_write_marked_extents(struct btrfs_root *root,
621 struct extent_io_tree *dirty_pages, int mark)
622{
623 int err = 0;
624 int werr = 0;
625 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
626 u64 start = 0;
627 u64 end;
628
629 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
630 mark)) {
631 convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark,
632 GFP_NOFS);
633 err = filemap_fdatawrite_range(mapping, start, end);
634 if (err)
635 werr = err;
636 cond_resched();
637 start = end + 1;
638 }
639 if (err)
640 werr = err;
641 return werr;
642}
643
644/*
645 * when btree blocks are allocated, they have some corresponding bits set for
646 * them in one of two extent_io trees. This is used to make sure all of
647 * those extents are on disk for transaction or log commit. We wait
648 * on all the pages and clear them from the dirty pages state tree
649 */
650int btrfs_wait_marked_extents(struct btrfs_root *root,
651 struct extent_io_tree *dirty_pages, int mark)
652{
653 int err = 0;
654 int werr = 0;
655 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
656 u64 start = 0;
657 u64 end;
658
659 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
660 EXTENT_NEED_WAIT)) {
661 clear_extent_bits(dirty_pages, start, end, EXTENT_NEED_WAIT, GFP_NOFS);
662 err = filemap_fdatawait_range(mapping, start, end);
663 if (err)
664 werr = err;
665 cond_resched();
666 start = end + 1;
667 }
668 if (err)
669 werr = err;
670 return werr;
671}
672
673/*
674 * when btree blocks are allocated, they have some corresponding bits set for
675 * them in one of two extent_io trees. This is used to make sure all of
676 * those extents are on disk for transaction or log commit
677 */
678int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
679 struct extent_io_tree *dirty_pages, int mark)
680{
681 int ret;
682 int ret2;
683
684 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
685 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
686
687 if (ret)
688 return ret;
689 if (ret2)
690 return ret2;
691 return 0;
692}
693
694int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
695 struct btrfs_root *root)
696{
697 if (!trans || !trans->transaction) {
698 struct inode *btree_inode;
699 btree_inode = root->fs_info->btree_inode;
700 return filemap_write_and_wait(btree_inode->i_mapping);
701 }
702 return btrfs_write_and_wait_marked_extents(root,
703 &trans->transaction->dirty_pages,
704 EXTENT_DIRTY);
705}
706
707/*
708 * this is used to update the root pointer in the tree of tree roots.
709 *
710 * But, in the case of the extent allocation tree, updating the root
711 * pointer may allocate blocks which may change the root of the extent
712 * allocation tree.
713 *
714 * So, this loops and repeats and makes sure the cowonly root didn't
715 * change while the root pointer was being updated in the metadata.
716 */
717static int update_cowonly_root(struct btrfs_trans_handle *trans,
718 struct btrfs_root *root)
719{
720 int ret;
721 u64 old_root_bytenr;
722 u64 old_root_used;
723 struct btrfs_root *tree_root = root->fs_info->tree_root;
724
725 old_root_used = btrfs_root_used(&root->root_item);
726 btrfs_write_dirty_block_groups(trans, root);
727
728 while (1) {
729 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
730 if (old_root_bytenr == root->node->start &&
731 old_root_used == btrfs_root_used(&root->root_item))
732 break;
733
734 btrfs_set_root_node(&root->root_item, root->node);
735 ret = btrfs_update_root(trans, tree_root,
736 &root->root_key,
737 &root->root_item);
738 if (ret)
739 return ret;
740
741 old_root_used = btrfs_root_used(&root->root_item);
742 ret = btrfs_write_dirty_block_groups(trans, root);
743 if (ret)
744 return ret;
745 }
746
747 if (root != root->fs_info->extent_root)
748 switch_commit_root(root);
749
750 return 0;
751}
752
753/*
754 * update all the cowonly tree roots on disk
755 *
756 * The error handling in this function may not be obvious. Any of the
757 * failures will cause the file system to go offline. We still need
758 * to clean up the delayed refs.
759 */
760static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
761 struct btrfs_root *root)
762{
763 struct btrfs_fs_info *fs_info = root->fs_info;
764 struct list_head *next;
765 struct extent_buffer *eb;
766 int ret;
767
768 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
769 if (ret)
770 return ret;
771
772 eb = btrfs_lock_root_node(fs_info->tree_root);
773 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
774 0, &eb);
775 btrfs_tree_unlock(eb);
776 free_extent_buffer(eb);
777
778 if (ret)
779 return ret;
780
781 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
782 if (ret)
783 return ret;
784
785 ret = btrfs_run_dev_stats(trans, root->fs_info);
786 BUG_ON(ret);
787
788 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
789 next = fs_info->dirty_cowonly_roots.next;
790 list_del_init(next);
791 root = list_entry(next, struct btrfs_root, dirty_list);
792
793 ret = update_cowonly_root(trans, root);
794 if (ret)
795 return ret;
796 }
797
798 down_write(&fs_info->extent_commit_sem);
799 switch_commit_root(fs_info->extent_root);
800 up_write(&fs_info->extent_commit_sem);
801
802 return 0;
803}
804
805/*
806 * dead roots are old snapshots that need to be deleted. This allocates
807 * a dirty root struct and adds it into the list of dead roots that need to
808 * be deleted
809 */
810int btrfs_add_dead_root(struct btrfs_root *root)
811{
812 spin_lock(&root->fs_info->trans_lock);
813 list_add(&root->root_list, &root->fs_info->dead_roots);
814 spin_unlock(&root->fs_info->trans_lock);
815 return 0;
816}
817
818/*
819 * update all the cowonly tree roots on disk
820 */
821static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
822 struct btrfs_root *root)
823{
824 struct btrfs_root *gang[8];
825 struct btrfs_fs_info *fs_info = root->fs_info;
826 int i;
827 int ret;
828 int err = 0;
829
830 spin_lock(&fs_info->fs_roots_radix_lock);
831 while (1) {
832 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
833 (void **)gang, 0,
834 ARRAY_SIZE(gang),
835 BTRFS_ROOT_TRANS_TAG);
836 if (ret == 0)
837 break;
838 for (i = 0; i < ret; i++) {
839 root = gang[i];
840 radix_tree_tag_clear(&fs_info->fs_roots_radix,
841 (unsigned long)root->root_key.objectid,
842 BTRFS_ROOT_TRANS_TAG);
843 spin_unlock(&fs_info->fs_roots_radix_lock);
844
845 btrfs_free_log(trans, root);
846 btrfs_update_reloc_root(trans, root);
847 btrfs_orphan_commit_root(trans, root);
848
849 btrfs_save_ino_cache(root, trans);
850
851 /* see comments in should_cow_block() */
852 root->force_cow = 0;
853 smp_wmb();
854
855 if (root->commit_root != root->node) {
856 mutex_lock(&root->fs_commit_mutex);
857 switch_commit_root(root);
858 btrfs_unpin_free_ino(root);
859 mutex_unlock(&root->fs_commit_mutex);
860
861 btrfs_set_root_node(&root->root_item,
862 root->node);
863 }
864
865 err = btrfs_update_root(trans, fs_info->tree_root,
866 &root->root_key,
867 &root->root_item);
868 spin_lock(&fs_info->fs_roots_radix_lock);
869 if (err)
870 break;
871 }
872 }
873 spin_unlock(&fs_info->fs_roots_radix_lock);
874 return err;
875}
876
877/*
878 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
879 * otherwise every leaf in the btree is read and defragged.
880 */
881int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
882{
883 struct btrfs_fs_info *info = root->fs_info;
884 struct btrfs_trans_handle *trans;
885 int ret;
886 unsigned long nr;
887
888 if (xchg(&root->defrag_running, 1))
889 return 0;
890
891 while (1) {
892 trans = btrfs_start_transaction(root, 0);
893 if (IS_ERR(trans))
894 return PTR_ERR(trans);
895
896 ret = btrfs_defrag_leaves(trans, root, cacheonly);
897
898 nr = trans->blocks_used;
899 btrfs_end_transaction(trans, root);
900 btrfs_btree_balance_dirty(info->tree_root, nr);
901 cond_resched();
902
903 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
904 break;
905 }
906 root->defrag_running = 0;
907 return ret;
908}
909
910/*
911 * new snapshots need to be created at a very specific time in the
912 * transaction commit. This does the actual creation
913 */
914static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
915 struct btrfs_fs_info *fs_info,
916 struct btrfs_pending_snapshot *pending)
917{
918 struct btrfs_key key;
919 struct btrfs_root_item *new_root_item;
920 struct btrfs_root *tree_root = fs_info->tree_root;
921 struct btrfs_root *root = pending->root;
922 struct btrfs_root *parent_root;
923 struct btrfs_block_rsv *rsv;
924 struct inode *parent_inode;
925 struct dentry *parent;
926 struct dentry *dentry;
927 struct extent_buffer *tmp;
928 struct extent_buffer *old;
929 int ret;
930 u64 to_reserve = 0;
931 u64 index = 0;
932 u64 objectid;
933 u64 root_flags;
934
935 rsv = trans->block_rsv;
936
937 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
938 if (!new_root_item) {
939 ret = pending->error = -ENOMEM;
940 goto fail;
941 }
942
943 ret = btrfs_find_free_objectid(tree_root, &objectid);
944 if (ret) {
945 pending->error = ret;
946 goto fail;
947 }
948
949 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
950
951 if (to_reserve > 0) {
952 ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
953 to_reserve);
954 if (ret) {
955 pending->error = ret;
956 goto fail;
957 }
958 }
959
960 key.objectid = objectid;
961 key.offset = (u64)-1;
962 key.type = BTRFS_ROOT_ITEM_KEY;
963
964 trans->block_rsv = &pending->block_rsv;
965
966 dentry = pending->dentry;
967 parent = dget_parent(dentry);
968 parent_inode = parent->d_inode;
969 parent_root = BTRFS_I(parent_inode)->root;
970 record_root_in_trans(trans, parent_root);
971
972 /*
973 * insert the directory item
974 */
975 ret = btrfs_set_inode_index(parent_inode, &index);
976 BUG_ON(ret); /* -ENOMEM */
977 ret = btrfs_insert_dir_item(trans, parent_root,
978 dentry->d_name.name, dentry->d_name.len,
979 parent_inode, &key,
980 BTRFS_FT_DIR, index);
981 if (ret == -EEXIST) {
982 pending->error = -EEXIST;
983 dput(parent);
984 goto fail;
985 } else if (ret) {
986 goto abort_trans_dput;
987 }
988
989 btrfs_i_size_write(parent_inode, parent_inode->i_size +
990 dentry->d_name.len * 2);
991 ret = btrfs_update_inode(trans, parent_root, parent_inode);
992 if (ret)
993 goto abort_trans_dput;
994
995 /*
996 * pull in the delayed directory update
997 * and the delayed inode item
998 * otherwise we corrupt the FS during
999 * snapshot
1000 */
1001 ret = btrfs_run_delayed_items(trans, root);
1002 if (ret) { /* Transaction aborted */
1003 dput(parent);
1004 goto fail;
1005 }
1006
1007 record_root_in_trans(trans, root);
1008 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1009 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1010 btrfs_check_and_init_root_item(new_root_item);
1011
1012 root_flags = btrfs_root_flags(new_root_item);
1013 if (pending->readonly)
1014 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1015 else
1016 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1017 btrfs_set_root_flags(new_root_item, root_flags);
1018
1019 old = btrfs_lock_root_node(root);
1020 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1021 if (ret) {
1022 btrfs_tree_unlock(old);
1023 free_extent_buffer(old);
1024 goto abort_trans_dput;
1025 }
1026
1027 btrfs_set_lock_blocking(old);
1028
1029 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1030 /* clean up in any case */
1031 btrfs_tree_unlock(old);
1032 free_extent_buffer(old);
1033 if (ret)
1034 goto abort_trans_dput;
1035
1036 /* see comments in should_cow_block() */
1037 root->force_cow = 1;
1038 smp_wmb();
1039
1040 btrfs_set_root_node(new_root_item, tmp);
1041 /* record when the snapshot was created in key.offset */
1042 key.offset = trans->transid;
1043 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1044 btrfs_tree_unlock(tmp);
1045 free_extent_buffer(tmp);
1046 if (ret)
1047 goto abort_trans_dput;
1048
1049 /*
1050 * insert root back/forward references
1051 */
1052 ret = btrfs_add_root_ref(trans, tree_root, objectid,
1053 parent_root->root_key.objectid,
1054 btrfs_ino(parent_inode), index,
1055 dentry->d_name.name, dentry->d_name.len);
1056 dput(parent);
1057 if (ret)
1058 goto fail;
1059
1060 key.offset = (u64)-1;
1061 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1062 if (IS_ERR(pending->snap)) {
1063 ret = PTR_ERR(pending->snap);
1064 goto abort_trans;
1065 }
1066
1067 ret = btrfs_reloc_post_snapshot(trans, pending);
1068 if (ret)
1069 goto abort_trans;
1070 ret = 0;
1071fail:
1072 kfree(new_root_item);
1073 trans->block_rsv = rsv;
1074 btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1075 return ret;
1076
1077abort_trans_dput:
1078 dput(parent);
1079abort_trans:
1080 btrfs_abort_transaction(trans, root, ret);
1081 goto fail;
1082}
1083
1084/*
1085 * create all the snapshots we've scheduled for creation
1086 */
1087static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1088 struct btrfs_fs_info *fs_info)
1089{
1090 struct btrfs_pending_snapshot *pending;
1091 struct list_head *head = &trans->transaction->pending_snapshots;
1092
1093 list_for_each_entry(pending, head, list)
1094 create_pending_snapshot(trans, fs_info, pending);
1095 return 0;
1096}
1097
1098static void update_super_roots(struct btrfs_root *root)
1099{
1100 struct btrfs_root_item *root_item;
1101 struct btrfs_super_block *super;
1102
1103 super = root->fs_info->super_copy;
1104
1105 root_item = &root->fs_info->chunk_root->root_item;
1106 super->chunk_root = root_item->bytenr;
1107 super->chunk_root_generation = root_item->generation;
1108 super->chunk_root_level = root_item->level;
1109
1110 root_item = &root->fs_info->tree_root->root_item;
1111 super->root = root_item->bytenr;
1112 super->generation = root_item->generation;
1113 super->root_level = root_item->level;
1114 if (btrfs_test_opt(root, SPACE_CACHE))
1115 super->cache_generation = root_item->generation;
1116}
1117
1118int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1119{
1120 int ret = 0;
1121 spin_lock(&info->trans_lock);
1122 if (info->running_transaction)
1123 ret = info->running_transaction->in_commit;
1124 spin_unlock(&info->trans_lock);
1125 return ret;
1126}
1127
1128int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1129{
1130 int ret = 0;
1131 spin_lock(&info->trans_lock);
1132 if (info->running_transaction)
1133 ret = info->running_transaction->blocked;
1134 spin_unlock(&info->trans_lock);
1135 return ret;
1136}
1137
1138/*
1139 * wait for the current transaction commit to start and block subsequent
1140 * transaction joins
1141 */
1142static void wait_current_trans_commit_start(struct btrfs_root *root,
1143 struct btrfs_transaction *trans)
1144{
1145 wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
1146}
1147
1148/*
1149 * wait for the current transaction to start and then become unblocked.
1150 * caller holds ref.
1151 */
1152static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1153 struct btrfs_transaction *trans)
1154{
1155 wait_event(root->fs_info->transaction_wait,
1156 trans->commit_done || (trans->in_commit && !trans->blocked));
1157}
1158
1159/*
1160 * commit transactions asynchronously. once btrfs_commit_transaction_async
1161 * returns, any subsequent transaction will not be allowed to join.
1162 */
1163struct btrfs_async_commit {
1164 struct btrfs_trans_handle *newtrans;
1165 struct btrfs_root *root;
1166 struct delayed_work work;
1167};
1168
1169static void do_async_commit(struct work_struct *work)
1170{
1171 struct btrfs_async_commit *ac =
1172 container_of(work, struct btrfs_async_commit, work.work);
1173
1174 btrfs_commit_transaction(ac->newtrans, ac->root);
1175 kfree(ac);
1176}
1177
1178int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1179 struct btrfs_root *root,
1180 int wait_for_unblock)
1181{
1182 struct btrfs_async_commit *ac;
1183 struct btrfs_transaction *cur_trans;
1184
1185 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1186 if (!ac)
1187 return -ENOMEM;
1188
1189 INIT_DELAYED_WORK(&ac->work, do_async_commit);
1190 ac->root = root;
1191 ac->newtrans = btrfs_join_transaction(root);
1192 if (IS_ERR(ac->newtrans)) {
1193 int err = PTR_ERR(ac->newtrans);
1194 kfree(ac);
1195 return err;
1196 }
1197
1198 /* take transaction reference */
1199 cur_trans = trans->transaction;
1200 atomic_inc(&cur_trans->use_count);
1201
1202 btrfs_end_transaction(trans, root);
1203 schedule_delayed_work(&ac->work, 0);
1204
1205 /* wait for transaction to start and unblock */
1206 if (wait_for_unblock)
1207 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1208 else
1209 wait_current_trans_commit_start(root, cur_trans);
1210
1211 if (current->journal_info == trans)
1212 current->journal_info = NULL;
1213
1214 put_transaction(cur_trans);
1215 return 0;
1216}
1217
1218
1219static void cleanup_transaction(struct btrfs_trans_handle *trans,
1220 struct btrfs_root *root, int err)
1221{
1222 struct btrfs_transaction *cur_trans = trans->transaction;
1223
1224 WARN_ON(trans->use_count > 1);
1225
1226 btrfs_abort_transaction(trans, root, err);
1227
1228 spin_lock(&root->fs_info->trans_lock);
1229 list_del_init(&cur_trans->list);
1230 if (cur_trans == root->fs_info->running_transaction) {
1231 root->fs_info->running_transaction = NULL;
1232 root->fs_info->trans_no_join = 0;
1233 }
1234 spin_unlock(&root->fs_info->trans_lock);
1235
1236 btrfs_cleanup_one_transaction(trans->transaction, root);
1237
1238 put_transaction(cur_trans);
1239 put_transaction(cur_trans);
1240
1241 trace_btrfs_transaction_commit(root);
1242
1243 btrfs_scrub_continue(root);
1244
1245 if (current->journal_info == trans)
1246 current->journal_info = NULL;
1247
1248 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1249}
1250
1251/*
1252 * btrfs_transaction state sequence:
1253 * in_commit = 0, blocked = 0 (initial)
1254 * in_commit = 1, blocked = 1
1255 * blocked = 0
1256 * commit_done = 1
1257 */
1258int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1259 struct btrfs_root *root)
1260{
1261 unsigned long joined = 0;
1262 struct btrfs_transaction *cur_trans = trans->transaction;
1263 struct btrfs_transaction *prev_trans = NULL;
1264 DEFINE_WAIT(wait);
1265 int ret = -EIO;
1266 int should_grow = 0;
1267 unsigned long now = get_seconds();
1268 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1269
1270 btrfs_run_ordered_operations(root, 0);
1271
1272 btrfs_trans_release_metadata(trans, root);
1273 trans->block_rsv = NULL;
1274
1275 if (cur_trans->aborted)
1276 goto cleanup_transaction;
1277
1278 /* make a pass through all the delayed refs we have so far
1279 * any runnings procs may add more while we are here
1280 */
1281 ret = btrfs_run_delayed_refs(trans, root, 0);
1282 if (ret)
1283 goto cleanup_transaction;
1284
1285 cur_trans = trans->transaction;
1286
1287 /*
1288 * set the flushing flag so procs in this transaction have to
1289 * start sending their work down.
1290 */
1291 cur_trans->delayed_refs.flushing = 1;
1292
1293 ret = btrfs_run_delayed_refs(trans, root, 0);
1294 if (ret)
1295 goto cleanup_transaction;
1296
1297 spin_lock(&cur_trans->commit_lock);
1298 if (cur_trans->in_commit) {
1299 spin_unlock(&cur_trans->commit_lock);
1300 atomic_inc(&cur_trans->use_count);
1301 ret = btrfs_end_transaction(trans, root);
1302
1303 wait_for_commit(root, cur_trans);
1304
1305 put_transaction(cur_trans);
1306
1307 return ret;
1308 }
1309
1310 trans->transaction->in_commit = 1;
1311 trans->transaction->blocked = 1;
1312 spin_unlock(&cur_trans->commit_lock);
1313 wake_up(&root->fs_info->transaction_blocked_wait);
1314
1315 spin_lock(&root->fs_info->trans_lock);
1316 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1317 prev_trans = list_entry(cur_trans->list.prev,
1318 struct btrfs_transaction, list);
1319 if (!prev_trans->commit_done) {
1320 atomic_inc(&prev_trans->use_count);
1321 spin_unlock(&root->fs_info->trans_lock);
1322
1323 wait_for_commit(root, prev_trans);
1324
1325 put_transaction(prev_trans);
1326 } else {
1327 spin_unlock(&root->fs_info->trans_lock);
1328 }
1329 } else {
1330 spin_unlock(&root->fs_info->trans_lock);
1331 }
1332
1333 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1334 should_grow = 1;
1335
1336 do {
1337 int snap_pending = 0;
1338
1339 joined = cur_trans->num_joined;
1340 if (!list_empty(&trans->transaction->pending_snapshots))
1341 snap_pending = 1;
1342
1343 WARN_ON(cur_trans != trans->transaction);
1344
1345 if (flush_on_commit || snap_pending) {
1346 btrfs_start_delalloc_inodes(root, 1);
1347 btrfs_wait_ordered_extents(root, 0, 1);
1348 }
1349
1350 ret = btrfs_run_delayed_items(trans, root);
1351 if (ret)
1352 goto cleanup_transaction;
1353
1354 /*
1355 * rename don't use btrfs_join_transaction, so, once we
1356 * set the transaction to blocked above, we aren't going
1357 * to get any new ordered operations. We can safely run
1358 * it here and no for sure that nothing new will be added
1359 * to the list
1360 */
1361 btrfs_run_ordered_operations(root, 1);
1362
1363 prepare_to_wait(&cur_trans->writer_wait, &wait,
1364 TASK_UNINTERRUPTIBLE);
1365
1366 if (atomic_read(&cur_trans->num_writers) > 1)
1367 schedule_timeout(MAX_SCHEDULE_TIMEOUT);
1368 else if (should_grow)
1369 schedule_timeout(1);
1370
1371 finish_wait(&cur_trans->writer_wait, &wait);
1372 } while (atomic_read(&cur_trans->num_writers) > 1 ||
1373 (should_grow && cur_trans->num_joined != joined));
1374
1375 /*
1376 * Ok now we need to make sure to block out any other joins while we
1377 * commit the transaction. We could have started a join before setting
1378 * no_join so make sure to wait for num_writers to == 1 again.
1379 */
1380 spin_lock(&root->fs_info->trans_lock);
1381 root->fs_info->trans_no_join = 1;
1382 spin_unlock(&root->fs_info->trans_lock);
1383 wait_event(cur_trans->writer_wait,
1384 atomic_read(&cur_trans->num_writers) == 1);
1385
1386 /*
1387 * the reloc mutex makes sure that we stop
1388 * the balancing code from coming in and moving
1389 * extents around in the middle of the commit
1390 */
1391 mutex_lock(&root->fs_info->reloc_mutex);
1392
1393 ret = btrfs_run_delayed_items(trans, root);
1394 if (ret) {
1395 mutex_unlock(&root->fs_info->reloc_mutex);
1396 goto cleanup_transaction;
1397 }
1398
1399 ret = create_pending_snapshots(trans, root->fs_info);
1400 if (ret) {
1401 mutex_unlock(&root->fs_info->reloc_mutex);
1402 goto cleanup_transaction;
1403 }
1404
1405 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1406 if (ret) {
1407 mutex_unlock(&root->fs_info->reloc_mutex);
1408 goto cleanup_transaction;
1409 }
1410
1411 /*
1412 * make sure none of the code above managed to slip in a
1413 * delayed item
1414 */
1415 btrfs_assert_delayed_root_empty(root);
1416
1417 WARN_ON(cur_trans != trans->transaction);
1418
1419 btrfs_scrub_pause(root);
1420 /* btrfs_commit_tree_roots is responsible for getting the
1421 * various roots consistent with each other. Every pointer
1422 * in the tree of tree roots has to point to the most up to date
1423 * root for every subvolume and other tree. So, we have to keep
1424 * the tree logging code from jumping in and changing any
1425 * of the trees.
1426 *
1427 * At this point in the commit, there can't be any tree-log
1428 * writers, but a little lower down we drop the trans mutex
1429 * and let new people in. By holding the tree_log_mutex
1430 * from now until after the super is written, we avoid races
1431 * with the tree-log code.
1432 */
1433 mutex_lock(&root->fs_info->tree_log_mutex);
1434
1435 ret = commit_fs_roots(trans, root);
1436 if (ret) {
1437 mutex_unlock(&root->fs_info->tree_log_mutex);
1438 mutex_unlock(&root->fs_info->reloc_mutex);
1439 goto cleanup_transaction;
1440 }
1441
1442 /* commit_fs_roots gets rid of all the tree log roots, it is now
1443 * safe to free the root of tree log roots
1444 */
1445 btrfs_free_log_root_tree(trans, root->fs_info);
1446
1447 ret = commit_cowonly_roots(trans, root);
1448 if (ret) {
1449 mutex_unlock(&root->fs_info->tree_log_mutex);
1450 mutex_unlock(&root->fs_info->reloc_mutex);
1451 goto cleanup_transaction;
1452 }
1453
1454 btrfs_prepare_extent_commit(trans, root);
1455
1456 cur_trans = root->fs_info->running_transaction;
1457
1458 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1459 root->fs_info->tree_root->node);
1460 switch_commit_root(root->fs_info->tree_root);
1461
1462 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1463 root->fs_info->chunk_root->node);
1464 switch_commit_root(root->fs_info->chunk_root);
1465
1466 update_super_roots(root);
1467
1468 if (!root->fs_info->log_root_recovering) {
1469 btrfs_set_super_log_root(root->fs_info->super_copy, 0);
1470 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1471 }
1472
1473 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
1474 sizeof(*root->fs_info->super_copy));
1475
1476 trans->transaction->blocked = 0;
1477 spin_lock(&root->fs_info->trans_lock);
1478 root->fs_info->running_transaction = NULL;
1479 root->fs_info->trans_no_join = 0;
1480 spin_unlock(&root->fs_info->trans_lock);
1481 mutex_unlock(&root->fs_info->reloc_mutex);
1482
1483 wake_up(&root->fs_info->transaction_wait);
1484
1485 ret = btrfs_write_and_wait_transaction(trans, root);
1486 if (ret) {
1487 btrfs_error(root->fs_info, ret,
1488 "Error while writing out transaction.");
1489 mutex_unlock(&root->fs_info->tree_log_mutex);
1490 goto cleanup_transaction;
1491 }
1492
1493 ret = write_ctree_super(trans, root, 0);
1494 if (ret) {
1495 mutex_unlock(&root->fs_info->tree_log_mutex);
1496 goto cleanup_transaction;
1497 }
1498
1499 /*
1500 * the super is written, we can safely allow the tree-loggers
1501 * to go about their business
1502 */
1503 mutex_unlock(&root->fs_info->tree_log_mutex);
1504
1505 btrfs_finish_extent_commit(trans, root);
1506
1507 cur_trans->commit_done = 1;
1508
1509 root->fs_info->last_trans_committed = cur_trans->transid;
1510
1511 wake_up(&cur_trans->commit_wait);
1512
1513 spin_lock(&root->fs_info->trans_lock);
1514 list_del_init(&cur_trans->list);
1515 spin_unlock(&root->fs_info->trans_lock);
1516
1517 put_transaction(cur_trans);
1518 put_transaction(cur_trans);
1519
1520 trace_btrfs_transaction_commit(root);
1521
1522 btrfs_scrub_continue(root);
1523
1524 if (current->journal_info == trans)
1525 current->journal_info = NULL;
1526
1527 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1528
1529 if (current != root->fs_info->transaction_kthread)
1530 btrfs_run_delayed_iputs(root);
1531
1532 return ret;
1533
1534cleanup_transaction:
1535 btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
1536// WARN_ON(1);
1537 if (current->journal_info == trans)
1538 current->journal_info = NULL;
1539 cleanup_transaction(trans, root, ret);
1540
1541 return ret;
1542}
1543
1544/*
1545 * interface function to delete all the snapshots we have scheduled for deletion
1546 */
1547int btrfs_clean_old_snapshots(struct btrfs_root *root)
1548{
1549 LIST_HEAD(list);
1550 struct btrfs_fs_info *fs_info = root->fs_info;
1551
1552 spin_lock(&fs_info->trans_lock);
1553 list_splice_init(&fs_info->dead_roots, &list);
1554 spin_unlock(&fs_info->trans_lock);
1555
1556 while (!list_empty(&list)) {
1557 int ret;
1558
1559 root = list_entry(list.next, struct btrfs_root, root_list);
1560 list_del(&root->root_list);
1561
1562 btrfs_kill_all_delayed_nodes(root);
1563
1564 if (btrfs_header_backref_rev(root->node) <
1565 BTRFS_MIXED_BACKREF_REV)
1566 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1567 else
1568 ret =btrfs_drop_snapshot(root, NULL, 1, 0);
1569 BUG_ON(ret < 0);
1570 }
1571 return 0;
1572}