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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// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/slab.h>
8#include <linux/sched.h>
9#include <linux/writeback.h>
10#include <linux/pagemap.h>
11#include <linux/blkdev.h>
12#include <linux/uuid.h>
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "locking.h"
17#include "tree-log.h"
18#include "inode-map.h"
19#include "volumes.h"
20#include "dev-replace.h"
21#include "qgroup.h"
22
23#define BTRFS_ROOT_TRANS_TAG 0
24
25static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
26 [TRANS_STATE_RUNNING] = 0U,
27 [TRANS_STATE_BLOCKED] = __TRANS_START,
28 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
29 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
30 __TRANS_ATTACH |
31 __TRANS_JOIN),
32 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
33 __TRANS_ATTACH |
34 __TRANS_JOIN |
35 __TRANS_JOIN_NOLOCK),
36 [TRANS_STATE_COMPLETED] = (__TRANS_START |
37 __TRANS_ATTACH |
38 __TRANS_JOIN |
39 __TRANS_JOIN_NOLOCK),
40};
41
42void btrfs_put_transaction(struct btrfs_transaction *transaction)
43{
44 WARN_ON(refcount_read(&transaction->use_count) == 0);
45 if (refcount_dec_and_test(&transaction->use_count)) {
46 BUG_ON(!list_empty(&transaction->list));
47 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
48 if (transaction->delayed_refs.pending_csums)
49 btrfs_err(transaction->fs_info,
50 "pending csums is %llu",
51 transaction->delayed_refs.pending_csums);
52 while (!list_empty(&transaction->pending_chunks)) {
53 struct extent_map *em;
54
55 em = list_first_entry(&transaction->pending_chunks,
56 struct extent_map, list);
57 list_del_init(&em->list);
58 free_extent_map(em);
59 }
60 /*
61 * If any block groups are found in ->deleted_bgs then it's
62 * because the transaction was aborted and a commit did not
63 * happen (things failed before writing the new superblock
64 * and calling btrfs_finish_extent_commit()), so we can not
65 * discard the physical locations of the block groups.
66 */
67 while (!list_empty(&transaction->deleted_bgs)) {
68 struct btrfs_block_group_cache *cache;
69
70 cache = list_first_entry(&transaction->deleted_bgs,
71 struct btrfs_block_group_cache,
72 bg_list);
73 list_del_init(&cache->bg_list);
74 btrfs_put_block_group_trimming(cache);
75 btrfs_put_block_group(cache);
76 }
77 kfree(transaction);
78 }
79}
80
81static void clear_btree_io_tree(struct extent_io_tree *tree)
82{
83 spin_lock(&tree->lock);
84 /*
85 * Do a single barrier for the waitqueue_active check here, the state
86 * of the waitqueue should not change once clear_btree_io_tree is
87 * called.
88 */
89 smp_mb();
90 while (!RB_EMPTY_ROOT(&tree->state)) {
91 struct rb_node *node;
92 struct extent_state *state;
93
94 node = rb_first(&tree->state);
95 state = rb_entry(node, struct extent_state, rb_node);
96 rb_erase(&state->rb_node, &tree->state);
97 RB_CLEAR_NODE(&state->rb_node);
98 /*
99 * btree io trees aren't supposed to have tasks waiting for
100 * changes in the flags of extent states ever.
101 */
102 ASSERT(!waitqueue_active(&state->wq));
103 free_extent_state(state);
104
105 cond_resched_lock(&tree->lock);
106 }
107 spin_unlock(&tree->lock);
108}
109
110static noinline void switch_commit_roots(struct btrfs_transaction *trans)
111{
112 struct btrfs_fs_info *fs_info = trans->fs_info;
113 struct btrfs_root *root, *tmp;
114
115 down_write(&fs_info->commit_root_sem);
116 list_for_each_entry_safe(root, tmp, &trans->switch_commits,
117 dirty_list) {
118 list_del_init(&root->dirty_list);
119 free_extent_buffer(root->commit_root);
120 root->commit_root = btrfs_root_node(root);
121 if (is_fstree(root->objectid))
122 btrfs_unpin_free_ino(root);
123 clear_btree_io_tree(&root->dirty_log_pages);
124 }
125
126 /* We can free old roots now. */
127 spin_lock(&trans->dropped_roots_lock);
128 while (!list_empty(&trans->dropped_roots)) {
129 root = list_first_entry(&trans->dropped_roots,
130 struct btrfs_root, root_list);
131 list_del_init(&root->root_list);
132 spin_unlock(&trans->dropped_roots_lock);
133 btrfs_drop_and_free_fs_root(fs_info, root);
134 spin_lock(&trans->dropped_roots_lock);
135 }
136 spin_unlock(&trans->dropped_roots_lock);
137 up_write(&fs_info->commit_root_sem);
138}
139
140static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
141 unsigned int type)
142{
143 if (type & TRANS_EXTWRITERS)
144 atomic_inc(&trans->num_extwriters);
145}
146
147static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
148 unsigned int type)
149{
150 if (type & TRANS_EXTWRITERS)
151 atomic_dec(&trans->num_extwriters);
152}
153
154static inline void extwriter_counter_init(struct btrfs_transaction *trans,
155 unsigned int type)
156{
157 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
158}
159
160static inline int extwriter_counter_read(struct btrfs_transaction *trans)
161{
162 return atomic_read(&trans->num_extwriters);
163}
164
165/*
166 * either allocate a new transaction or hop into the existing one
167 */
168static noinline int join_transaction(struct btrfs_fs_info *fs_info,
169 unsigned int type)
170{
171 struct btrfs_transaction *cur_trans;
172
173 spin_lock(&fs_info->trans_lock);
174loop:
175 /* The file system has been taken offline. No new transactions. */
176 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
177 spin_unlock(&fs_info->trans_lock);
178 return -EROFS;
179 }
180
181 cur_trans = fs_info->running_transaction;
182 if (cur_trans) {
183 if (cur_trans->aborted) {
184 spin_unlock(&fs_info->trans_lock);
185 return cur_trans->aborted;
186 }
187 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
188 spin_unlock(&fs_info->trans_lock);
189 return -EBUSY;
190 }
191 refcount_inc(&cur_trans->use_count);
192 atomic_inc(&cur_trans->num_writers);
193 extwriter_counter_inc(cur_trans, type);
194 spin_unlock(&fs_info->trans_lock);
195 return 0;
196 }
197 spin_unlock(&fs_info->trans_lock);
198
199 /*
200 * If we are ATTACH, we just want to catch the current transaction,
201 * and commit it. If there is no transaction, just return ENOENT.
202 */
203 if (type == TRANS_ATTACH)
204 return -ENOENT;
205
206 /*
207 * JOIN_NOLOCK only happens during the transaction commit, so
208 * it is impossible that ->running_transaction is NULL
209 */
210 BUG_ON(type == TRANS_JOIN_NOLOCK);
211
212 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
213 if (!cur_trans)
214 return -ENOMEM;
215
216 spin_lock(&fs_info->trans_lock);
217 if (fs_info->running_transaction) {
218 /*
219 * someone started a transaction after we unlocked. Make sure
220 * to redo the checks above
221 */
222 kfree(cur_trans);
223 goto loop;
224 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
225 spin_unlock(&fs_info->trans_lock);
226 kfree(cur_trans);
227 return -EROFS;
228 }
229
230 cur_trans->fs_info = fs_info;
231 atomic_set(&cur_trans->num_writers, 1);
232 extwriter_counter_init(cur_trans, type);
233 init_waitqueue_head(&cur_trans->writer_wait);
234 init_waitqueue_head(&cur_trans->commit_wait);
235 init_waitqueue_head(&cur_trans->pending_wait);
236 cur_trans->state = TRANS_STATE_RUNNING;
237 /*
238 * One for this trans handle, one so it will live on until we
239 * commit the transaction.
240 */
241 refcount_set(&cur_trans->use_count, 2);
242 atomic_set(&cur_trans->pending_ordered, 0);
243 cur_trans->flags = 0;
244 cur_trans->start_time = get_seconds();
245
246 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
247
248 cur_trans->delayed_refs.href_root = RB_ROOT;
249 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
250 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
251
252 /*
253 * although the tree mod log is per file system and not per transaction,
254 * the log must never go across transaction boundaries.
255 */
256 smp_mb();
257 if (!list_empty(&fs_info->tree_mod_seq_list))
258 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
259 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
260 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
261 atomic64_set(&fs_info->tree_mod_seq, 0);
262
263 spin_lock_init(&cur_trans->delayed_refs.lock);
264
265 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
266 INIT_LIST_HEAD(&cur_trans->pending_chunks);
267 INIT_LIST_HEAD(&cur_trans->switch_commits);
268 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
269 INIT_LIST_HEAD(&cur_trans->io_bgs);
270 INIT_LIST_HEAD(&cur_trans->dropped_roots);
271 mutex_init(&cur_trans->cache_write_mutex);
272 cur_trans->num_dirty_bgs = 0;
273 spin_lock_init(&cur_trans->dirty_bgs_lock);
274 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
275 spin_lock_init(&cur_trans->dropped_roots_lock);
276 list_add_tail(&cur_trans->list, &fs_info->trans_list);
277 extent_io_tree_init(&cur_trans->dirty_pages,
278 fs_info->btree_inode);
279 fs_info->generation++;
280 cur_trans->transid = fs_info->generation;
281 fs_info->running_transaction = cur_trans;
282 cur_trans->aborted = 0;
283 spin_unlock(&fs_info->trans_lock);
284
285 return 0;
286}
287
288/*
289 * this does all the record keeping required to make sure that a reference
290 * counted root is properly recorded in a given transaction. This is required
291 * to make sure the old root from before we joined the transaction is deleted
292 * when the transaction commits
293 */
294static int record_root_in_trans(struct btrfs_trans_handle *trans,
295 struct btrfs_root *root,
296 int force)
297{
298 struct btrfs_fs_info *fs_info = root->fs_info;
299
300 if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
301 root->last_trans < trans->transid) || force) {
302 WARN_ON(root == fs_info->extent_root);
303 WARN_ON(!force && root->commit_root != root->node);
304
305 /*
306 * see below for IN_TRANS_SETUP usage rules
307 * we have the reloc mutex held now, so there
308 * is only one writer in this function
309 */
310 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
311
312 /* make sure readers find IN_TRANS_SETUP before
313 * they find our root->last_trans update
314 */
315 smp_wmb();
316
317 spin_lock(&fs_info->fs_roots_radix_lock);
318 if (root->last_trans == trans->transid && !force) {
319 spin_unlock(&fs_info->fs_roots_radix_lock);
320 return 0;
321 }
322 radix_tree_tag_set(&fs_info->fs_roots_radix,
323 (unsigned long)root->root_key.objectid,
324 BTRFS_ROOT_TRANS_TAG);
325 spin_unlock(&fs_info->fs_roots_radix_lock);
326 root->last_trans = trans->transid;
327
328 /* this is pretty tricky. We don't want to
329 * take the relocation lock in btrfs_record_root_in_trans
330 * unless we're really doing the first setup for this root in
331 * this transaction.
332 *
333 * Normally we'd use root->last_trans as a flag to decide
334 * if we want to take the expensive mutex.
335 *
336 * But, we have to set root->last_trans before we
337 * init the relocation root, otherwise, we trip over warnings
338 * in ctree.c. The solution used here is to flag ourselves
339 * with root IN_TRANS_SETUP. When this is 1, we're still
340 * fixing up the reloc trees and everyone must wait.
341 *
342 * When this is zero, they can trust root->last_trans and fly
343 * through btrfs_record_root_in_trans without having to take the
344 * lock. smp_wmb() makes sure that all the writes above are
345 * done before we pop in the zero below
346 */
347 btrfs_init_reloc_root(trans, root);
348 smp_mb__before_atomic();
349 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
350 }
351 return 0;
352}
353
354
355void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
356 struct btrfs_root *root)
357{
358 struct btrfs_fs_info *fs_info = root->fs_info;
359 struct btrfs_transaction *cur_trans = trans->transaction;
360
361 /* Add ourselves to the transaction dropped list */
362 spin_lock(&cur_trans->dropped_roots_lock);
363 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
364 spin_unlock(&cur_trans->dropped_roots_lock);
365
366 /* Make sure we don't try to update the root at commit time */
367 spin_lock(&fs_info->fs_roots_radix_lock);
368 radix_tree_tag_clear(&fs_info->fs_roots_radix,
369 (unsigned long)root->root_key.objectid,
370 BTRFS_ROOT_TRANS_TAG);
371 spin_unlock(&fs_info->fs_roots_radix_lock);
372}
373
374int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
375 struct btrfs_root *root)
376{
377 struct btrfs_fs_info *fs_info = root->fs_info;
378
379 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
380 return 0;
381
382 /*
383 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
384 * and barriers
385 */
386 smp_rmb();
387 if (root->last_trans == trans->transid &&
388 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
389 return 0;
390
391 mutex_lock(&fs_info->reloc_mutex);
392 record_root_in_trans(trans, root, 0);
393 mutex_unlock(&fs_info->reloc_mutex);
394
395 return 0;
396}
397
398static inline int is_transaction_blocked(struct btrfs_transaction *trans)
399{
400 return (trans->state >= TRANS_STATE_BLOCKED &&
401 trans->state < TRANS_STATE_UNBLOCKED &&
402 !trans->aborted);
403}
404
405/* wait for commit against the current transaction to become unblocked
406 * when this is done, it is safe to start a new transaction, but the current
407 * transaction might not be fully on disk.
408 */
409static void wait_current_trans(struct btrfs_fs_info *fs_info)
410{
411 struct btrfs_transaction *cur_trans;
412
413 spin_lock(&fs_info->trans_lock);
414 cur_trans = fs_info->running_transaction;
415 if (cur_trans && is_transaction_blocked(cur_trans)) {
416 refcount_inc(&cur_trans->use_count);
417 spin_unlock(&fs_info->trans_lock);
418
419 wait_event(fs_info->transaction_wait,
420 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
421 cur_trans->aborted);
422 btrfs_put_transaction(cur_trans);
423 } else {
424 spin_unlock(&fs_info->trans_lock);
425 }
426}
427
428static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
429{
430 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
431 return 0;
432
433 if (type == TRANS_START)
434 return 1;
435
436 return 0;
437}
438
439static inline bool need_reserve_reloc_root(struct btrfs_root *root)
440{
441 struct btrfs_fs_info *fs_info = root->fs_info;
442
443 if (!fs_info->reloc_ctl ||
444 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
445 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
446 root->reloc_root)
447 return false;
448
449 return true;
450}
451
452static struct btrfs_trans_handle *
453start_transaction(struct btrfs_root *root, unsigned int num_items,
454 unsigned int type, enum btrfs_reserve_flush_enum flush,
455 bool enforce_qgroups)
456{
457 struct btrfs_fs_info *fs_info = root->fs_info;
458
459 struct btrfs_trans_handle *h;
460 struct btrfs_transaction *cur_trans;
461 u64 num_bytes = 0;
462 u64 qgroup_reserved = 0;
463 bool reloc_reserved = false;
464 int ret;
465
466 /* Send isn't supposed to start transactions. */
467 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
468
469 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
470 return ERR_PTR(-EROFS);
471
472 if (current->journal_info) {
473 WARN_ON(type & TRANS_EXTWRITERS);
474 h = current->journal_info;
475 refcount_inc(&h->use_count);
476 WARN_ON(refcount_read(&h->use_count) > 2);
477 h->orig_rsv = h->block_rsv;
478 h->block_rsv = NULL;
479 goto got_it;
480 }
481
482 /*
483 * Do the reservation before we join the transaction so we can do all
484 * the appropriate flushing if need be.
485 */
486 if (num_items && root != fs_info->chunk_root) {
487 qgroup_reserved = num_items * fs_info->nodesize;
488 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
489 enforce_qgroups);
490 if (ret)
491 return ERR_PTR(ret);
492
493 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
494 /*
495 * Do the reservation for the relocation root creation
496 */
497 if (need_reserve_reloc_root(root)) {
498 num_bytes += fs_info->nodesize;
499 reloc_reserved = true;
500 }
501
502 ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
503 num_bytes, flush);
504 if (ret)
505 goto reserve_fail;
506 }
507again:
508 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
509 if (!h) {
510 ret = -ENOMEM;
511 goto alloc_fail;
512 }
513
514 /*
515 * If we are JOIN_NOLOCK we're already committing a transaction and
516 * waiting on this guy, so we don't need to do the sb_start_intwrite
517 * because we're already holding a ref. We need this because we could
518 * have raced in and did an fsync() on a file which can kick a commit
519 * and then we deadlock with somebody doing a freeze.
520 *
521 * If we are ATTACH, it means we just want to catch the current
522 * transaction and commit it, so we needn't do sb_start_intwrite().
523 */
524 if (type & __TRANS_FREEZABLE)
525 sb_start_intwrite(fs_info->sb);
526
527 if (may_wait_transaction(fs_info, type))
528 wait_current_trans(fs_info);
529
530 do {
531 ret = join_transaction(fs_info, type);
532 if (ret == -EBUSY) {
533 wait_current_trans(fs_info);
534 if (unlikely(type == TRANS_ATTACH))
535 ret = -ENOENT;
536 }
537 } while (ret == -EBUSY);
538
539 if (ret < 0)
540 goto join_fail;
541
542 cur_trans = fs_info->running_transaction;
543
544 h->transid = cur_trans->transid;
545 h->transaction = cur_trans;
546 h->root = root;
547 refcount_set(&h->use_count, 1);
548 h->fs_info = root->fs_info;
549
550 h->type = type;
551 h->can_flush_pending_bgs = true;
552 INIT_LIST_HEAD(&h->new_bgs);
553
554 smp_mb();
555 if (cur_trans->state >= TRANS_STATE_BLOCKED &&
556 may_wait_transaction(fs_info, type)) {
557 current->journal_info = h;
558 btrfs_commit_transaction(h);
559 goto again;
560 }
561
562 if (num_bytes) {
563 trace_btrfs_space_reservation(fs_info, "transaction",
564 h->transid, num_bytes, 1);
565 h->block_rsv = &fs_info->trans_block_rsv;
566 h->bytes_reserved = num_bytes;
567 h->reloc_reserved = reloc_reserved;
568 }
569
570got_it:
571 btrfs_record_root_in_trans(h, root);
572
573 if (!current->journal_info)
574 current->journal_info = h;
575 return h;
576
577join_fail:
578 if (type & __TRANS_FREEZABLE)
579 sb_end_intwrite(fs_info->sb);
580 kmem_cache_free(btrfs_trans_handle_cachep, h);
581alloc_fail:
582 if (num_bytes)
583 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
584 num_bytes);
585reserve_fail:
586 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
587 return ERR_PTR(ret);
588}
589
590struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
591 unsigned int num_items)
592{
593 return start_transaction(root, num_items, TRANS_START,
594 BTRFS_RESERVE_FLUSH_ALL, true);
595}
596
597struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
598 struct btrfs_root *root,
599 unsigned int num_items,
600 int min_factor)
601{
602 struct btrfs_fs_info *fs_info = root->fs_info;
603 struct btrfs_trans_handle *trans;
604 u64 num_bytes;
605 int ret;
606
607 /*
608 * We have two callers: unlink and block group removal. The
609 * former should succeed even if we will temporarily exceed
610 * quota and the latter operates on the extent root so
611 * qgroup enforcement is ignored anyway.
612 */
613 trans = start_transaction(root, num_items, TRANS_START,
614 BTRFS_RESERVE_FLUSH_ALL, false);
615 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
616 return trans;
617
618 trans = btrfs_start_transaction(root, 0);
619 if (IS_ERR(trans))
620 return trans;
621
622 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
623 ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv,
624 num_bytes, min_factor);
625 if (ret) {
626 btrfs_end_transaction(trans);
627 return ERR_PTR(ret);
628 }
629
630 trans->block_rsv = &fs_info->trans_block_rsv;
631 trans->bytes_reserved = num_bytes;
632 trace_btrfs_space_reservation(fs_info, "transaction",
633 trans->transid, num_bytes, 1);
634
635 return trans;
636}
637
638struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
639{
640 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
641 true);
642}
643
644struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
645{
646 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
647 BTRFS_RESERVE_NO_FLUSH, true);
648}
649
650/*
651 * btrfs_attach_transaction() - catch the running transaction
652 *
653 * It is used when we want to commit the current the transaction, but
654 * don't want to start a new one.
655 *
656 * Note: If this function return -ENOENT, it just means there is no
657 * running transaction. But it is possible that the inactive transaction
658 * is still in the memory, not fully on disk. If you hope there is no
659 * inactive transaction in the fs when -ENOENT is returned, you should
660 * invoke
661 * btrfs_attach_transaction_barrier()
662 */
663struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
664{
665 return start_transaction(root, 0, TRANS_ATTACH,
666 BTRFS_RESERVE_NO_FLUSH, true);
667}
668
669/*
670 * btrfs_attach_transaction_barrier() - catch the running transaction
671 *
672 * It is similar to the above function, the differentia is this one
673 * will wait for all the inactive transactions until they fully
674 * complete.
675 */
676struct btrfs_trans_handle *
677btrfs_attach_transaction_barrier(struct btrfs_root *root)
678{
679 struct btrfs_trans_handle *trans;
680
681 trans = start_transaction(root, 0, TRANS_ATTACH,
682 BTRFS_RESERVE_NO_FLUSH, true);
683 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
684 btrfs_wait_for_commit(root->fs_info, 0);
685
686 return trans;
687}
688
689/* wait for a transaction commit to be fully complete */
690static noinline void wait_for_commit(struct btrfs_transaction *commit)
691{
692 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
693}
694
695int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
696{
697 struct btrfs_transaction *cur_trans = NULL, *t;
698 int ret = 0;
699
700 if (transid) {
701 if (transid <= fs_info->last_trans_committed)
702 goto out;
703
704 /* find specified transaction */
705 spin_lock(&fs_info->trans_lock);
706 list_for_each_entry(t, &fs_info->trans_list, list) {
707 if (t->transid == transid) {
708 cur_trans = t;
709 refcount_inc(&cur_trans->use_count);
710 ret = 0;
711 break;
712 }
713 if (t->transid > transid) {
714 ret = 0;
715 break;
716 }
717 }
718 spin_unlock(&fs_info->trans_lock);
719
720 /*
721 * The specified transaction doesn't exist, or we
722 * raced with btrfs_commit_transaction
723 */
724 if (!cur_trans) {
725 if (transid > fs_info->last_trans_committed)
726 ret = -EINVAL;
727 goto out;
728 }
729 } else {
730 /* find newest transaction that is committing | committed */
731 spin_lock(&fs_info->trans_lock);
732 list_for_each_entry_reverse(t, &fs_info->trans_list,
733 list) {
734 if (t->state >= TRANS_STATE_COMMIT_START) {
735 if (t->state == TRANS_STATE_COMPLETED)
736 break;
737 cur_trans = t;
738 refcount_inc(&cur_trans->use_count);
739 break;
740 }
741 }
742 spin_unlock(&fs_info->trans_lock);
743 if (!cur_trans)
744 goto out; /* nothing committing|committed */
745 }
746
747 wait_for_commit(cur_trans);
748 btrfs_put_transaction(cur_trans);
749out:
750 return ret;
751}
752
753void btrfs_throttle(struct btrfs_fs_info *fs_info)
754{
755 wait_current_trans(fs_info);
756}
757
758static int should_end_transaction(struct btrfs_trans_handle *trans)
759{
760 struct btrfs_fs_info *fs_info = trans->fs_info;
761
762 if (btrfs_check_space_for_delayed_refs(trans, fs_info))
763 return 1;
764
765 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
766}
767
768int btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
769{
770 struct btrfs_transaction *cur_trans = trans->transaction;
771 int updates;
772 int err;
773
774 smp_mb();
775 if (cur_trans->state >= TRANS_STATE_BLOCKED ||
776 cur_trans->delayed_refs.flushing)
777 return 1;
778
779 updates = trans->delayed_ref_updates;
780 trans->delayed_ref_updates = 0;
781 if (updates) {
782 err = btrfs_run_delayed_refs(trans, updates * 2);
783 if (err) /* Error code will also eval true */
784 return err;
785 }
786
787 return should_end_transaction(trans);
788}
789
790static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
791
792{
793 struct btrfs_fs_info *fs_info = trans->fs_info;
794
795 if (!trans->block_rsv) {
796 ASSERT(!trans->bytes_reserved);
797 return;
798 }
799
800 if (!trans->bytes_reserved)
801 return;
802
803 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
804 trace_btrfs_space_reservation(fs_info, "transaction",
805 trans->transid, trans->bytes_reserved, 0);
806 btrfs_block_rsv_release(fs_info, trans->block_rsv,
807 trans->bytes_reserved);
808 trans->bytes_reserved = 0;
809}
810
811static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
812 int throttle)
813{
814 struct btrfs_fs_info *info = trans->fs_info;
815 struct btrfs_transaction *cur_trans = trans->transaction;
816 u64 transid = trans->transid;
817 unsigned long cur = trans->delayed_ref_updates;
818 int lock = (trans->type != TRANS_JOIN_NOLOCK);
819 int err = 0;
820 int must_run_delayed_refs = 0;
821
822 if (refcount_read(&trans->use_count) > 1) {
823 refcount_dec(&trans->use_count);
824 trans->block_rsv = trans->orig_rsv;
825 return 0;
826 }
827
828 btrfs_trans_release_metadata(trans);
829 trans->block_rsv = NULL;
830
831 if (!list_empty(&trans->new_bgs))
832 btrfs_create_pending_block_groups(trans);
833
834 trans->delayed_ref_updates = 0;
835 if (!trans->sync) {
836 must_run_delayed_refs =
837 btrfs_should_throttle_delayed_refs(trans, info);
838 cur = max_t(unsigned long, cur, 32);
839
840 /*
841 * don't make the caller wait if they are from a NOLOCK
842 * or ATTACH transaction, it will deadlock with commit
843 */
844 if (must_run_delayed_refs == 1 &&
845 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH)))
846 must_run_delayed_refs = 2;
847 }
848
849 btrfs_trans_release_metadata(trans);
850 trans->block_rsv = NULL;
851
852 if (!list_empty(&trans->new_bgs))
853 btrfs_create_pending_block_groups(trans);
854
855 btrfs_trans_release_chunk_metadata(trans);
856
857 if (lock && should_end_transaction(trans) &&
858 READ_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
859 spin_lock(&info->trans_lock);
860 if (cur_trans->state == TRANS_STATE_RUNNING)
861 cur_trans->state = TRANS_STATE_BLOCKED;
862 spin_unlock(&info->trans_lock);
863 }
864
865 if (lock && READ_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
866 if (throttle)
867 return btrfs_commit_transaction(trans);
868 else
869 wake_up_process(info->transaction_kthread);
870 }
871
872 if (trans->type & __TRANS_FREEZABLE)
873 sb_end_intwrite(info->sb);
874
875 WARN_ON(cur_trans != info->running_transaction);
876 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
877 atomic_dec(&cur_trans->num_writers);
878 extwriter_counter_dec(cur_trans, trans->type);
879
880 /*
881 * Make sure counter is updated before we wake up waiters.
882 */
883 smp_mb();
884 if (waitqueue_active(&cur_trans->writer_wait))
885 wake_up(&cur_trans->writer_wait);
886 btrfs_put_transaction(cur_trans);
887
888 if (current->journal_info == trans)
889 current->journal_info = NULL;
890
891 if (throttle)
892 btrfs_run_delayed_iputs(info);
893
894 if (trans->aborted ||
895 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
896 wake_up_process(info->transaction_kthread);
897 err = -EIO;
898 }
899
900 kmem_cache_free(btrfs_trans_handle_cachep, trans);
901 if (must_run_delayed_refs) {
902 btrfs_async_run_delayed_refs(info, cur, transid,
903 must_run_delayed_refs == 1);
904 }
905 return err;
906}
907
908int btrfs_end_transaction(struct btrfs_trans_handle *trans)
909{
910 return __btrfs_end_transaction(trans, 0);
911}
912
913int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
914{
915 return __btrfs_end_transaction(trans, 1);
916}
917
918/*
919 * when btree blocks are allocated, they have some corresponding bits set for
920 * them in one of two extent_io trees. This is used to make sure all of
921 * those extents are sent to disk but does not wait on them
922 */
923int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
924 struct extent_io_tree *dirty_pages, int mark)
925{
926 int err = 0;
927 int werr = 0;
928 struct address_space *mapping = fs_info->btree_inode->i_mapping;
929 struct extent_state *cached_state = NULL;
930 u64 start = 0;
931 u64 end;
932
933 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
934 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
935 mark, &cached_state)) {
936 bool wait_writeback = false;
937
938 err = convert_extent_bit(dirty_pages, start, end,
939 EXTENT_NEED_WAIT,
940 mark, &cached_state);
941 /*
942 * convert_extent_bit can return -ENOMEM, which is most of the
943 * time a temporary error. So when it happens, ignore the error
944 * and wait for writeback of this range to finish - because we
945 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
946 * to __btrfs_wait_marked_extents() would not know that
947 * writeback for this range started and therefore wouldn't
948 * wait for it to finish - we don't want to commit a
949 * superblock that points to btree nodes/leafs for which
950 * writeback hasn't finished yet (and without errors).
951 * We cleanup any entries left in the io tree when committing
952 * the transaction (through clear_btree_io_tree()).
953 */
954 if (err == -ENOMEM) {
955 err = 0;
956 wait_writeback = true;
957 }
958 if (!err)
959 err = filemap_fdatawrite_range(mapping, start, end);
960 if (err)
961 werr = err;
962 else if (wait_writeback)
963 werr = filemap_fdatawait_range(mapping, start, end);
964 free_extent_state(cached_state);
965 cached_state = NULL;
966 cond_resched();
967 start = end + 1;
968 }
969 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
970 return werr;
971}
972
973/*
974 * when btree blocks are allocated, they have some corresponding bits set for
975 * them in one of two extent_io trees. This is used to make sure all of
976 * those extents are on disk for transaction or log commit. We wait
977 * on all the pages and clear them from the dirty pages state tree
978 */
979static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
980 struct extent_io_tree *dirty_pages)
981{
982 int err = 0;
983 int werr = 0;
984 struct address_space *mapping = fs_info->btree_inode->i_mapping;
985 struct extent_state *cached_state = NULL;
986 u64 start = 0;
987 u64 end;
988
989 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
990 EXTENT_NEED_WAIT, &cached_state)) {
991 /*
992 * Ignore -ENOMEM errors returned by clear_extent_bit().
993 * When committing the transaction, we'll remove any entries
994 * left in the io tree. For a log commit, we don't remove them
995 * after committing the log because the tree can be accessed
996 * concurrently - we do it only at transaction commit time when
997 * it's safe to do it (through clear_btree_io_tree()).
998 */
999 err = clear_extent_bit(dirty_pages, start, end,
1000 EXTENT_NEED_WAIT, 0, 0, &cached_state);
1001 if (err == -ENOMEM)
1002 err = 0;
1003 if (!err)
1004 err = filemap_fdatawait_range(mapping, start, end);
1005 if (err)
1006 werr = err;
1007 free_extent_state(cached_state);
1008 cached_state = NULL;
1009 cond_resched();
1010 start = end + 1;
1011 }
1012 if (err)
1013 werr = err;
1014 return werr;
1015}
1016
1017int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1018 struct extent_io_tree *dirty_pages)
1019{
1020 bool errors = false;
1021 int err;
1022
1023 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1024 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1025 errors = true;
1026
1027 if (errors && !err)
1028 err = -EIO;
1029 return err;
1030}
1031
1032int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1033{
1034 struct btrfs_fs_info *fs_info = log_root->fs_info;
1035 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1036 bool errors = false;
1037 int err;
1038
1039 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1040
1041 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1042 if ((mark & EXTENT_DIRTY) &&
1043 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1044 errors = true;
1045
1046 if ((mark & EXTENT_NEW) &&
1047 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1048 errors = true;
1049
1050 if (errors && !err)
1051 err = -EIO;
1052 return err;
1053}
1054
1055/*
1056 * When btree blocks are allocated the corresponding extents are marked dirty.
1057 * This function ensures such extents are persisted on disk for transaction or
1058 * log commit.
1059 *
1060 * @trans: transaction whose dirty pages we'd like to write
1061 */
1062static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1063{
1064 int ret;
1065 int ret2;
1066 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1067 struct btrfs_fs_info *fs_info = trans->fs_info;
1068 struct blk_plug plug;
1069
1070 blk_start_plug(&plug);
1071 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1072 blk_finish_plug(&plug);
1073 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1074
1075 clear_btree_io_tree(&trans->transaction->dirty_pages);
1076
1077 if (ret)
1078 return ret;
1079 else if (ret2)
1080 return ret2;
1081 else
1082 return 0;
1083}
1084
1085/*
1086 * this is used to update the root pointer in the tree of tree roots.
1087 *
1088 * But, in the case of the extent allocation tree, updating the root
1089 * pointer may allocate blocks which may change the root of the extent
1090 * allocation tree.
1091 *
1092 * So, this loops and repeats and makes sure the cowonly root didn't
1093 * change while the root pointer was being updated in the metadata.
1094 */
1095static int update_cowonly_root(struct btrfs_trans_handle *trans,
1096 struct btrfs_root *root)
1097{
1098 int ret;
1099 u64 old_root_bytenr;
1100 u64 old_root_used;
1101 struct btrfs_fs_info *fs_info = root->fs_info;
1102 struct btrfs_root *tree_root = fs_info->tree_root;
1103
1104 old_root_used = btrfs_root_used(&root->root_item);
1105
1106 while (1) {
1107 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1108 if (old_root_bytenr == root->node->start &&
1109 old_root_used == btrfs_root_used(&root->root_item))
1110 break;
1111
1112 btrfs_set_root_node(&root->root_item, root->node);
1113 ret = btrfs_update_root(trans, tree_root,
1114 &root->root_key,
1115 &root->root_item);
1116 if (ret)
1117 return ret;
1118
1119 old_root_used = btrfs_root_used(&root->root_item);
1120 }
1121
1122 return 0;
1123}
1124
1125/*
1126 * update all the cowonly tree roots on disk
1127 *
1128 * The error handling in this function may not be obvious. Any of the
1129 * failures will cause the file system to go offline. We still need
1130 * to clean up the delayed refs.
1131 */
1132static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1133{
1134 struct btrfs_fs_info *fs_info = trans->fs_info;
1135 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1136 struct list_head *io_bgs = &trans->transaction->io_bgs;
1137 struct list_head *next;
1138 struct extent_buffer *eb;
1139 int ret;
1140
1141 eb = btrfs_lock_root_node(fs_info->tree_root);
1142 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1143 0, &eb);
1144 btrfs_tree_unlock(eb);
1145 free_extent_buffer(eb);
1146
1147 if (ret)
1148 return ret;
1149
1150 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1151 if (ret)
1152 return ret;
1153
1154 ret = btrfs_run_dev_stats(trans, fs_info);
1155 if (ret)
1156 return ret;
1157 ret = btrfs_run_dev_replace(trans, fs_info);
1158 if (ret)
1159 return ret;
1160 ret = btrfs_run_qgroups(trans, fs_info);
1161 if (ret)
1162 return ret;
1163
1164 ret = btrfs_setup_space_cache(trans, fs_info);
1165 if (ret)
1166 return ret;
1167
1168 /* run_qgroups might have added some more refs */
1169 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1170 if (ret)
1171 return ret;
1172again:
1173 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1174 struct btrfs_root *root;
1175 next = fs_info->dirty_cowonly_roots.next;
1176 list_del_init(next);
1177 root = list_entry(next, struct btrfs_root, dirty_list);
1178 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1179
1180 if (root != fs_info->extent_root)
1181 list_add_tail(&root->dirty_list,
1182 &trans->transaction->switch_commits);
1183 ret = update_cowonly_root(trans, root);
1184 if (ret)
1185 return ret;
1186 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1187 if (ret)
1188 return ret;
1189 }
1190
1191 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1192 ret = btrfs_write_dirty_block_groups(trans, fs_info);
1193 if (ret)
1194 return ret;
1195 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1196 if (ret)
1197 return ret;
1198 }
1199
1200 if (!list_empty(&fs_info->dirty_cowonly_roots))
1201 goto again;
1202
1203 list_add_tail(&fs_info->extent_root->dirty_list,
1204 &trans->transaction->switch_commits);
1205 btrfs_after_dev_replace_commit(fs_info);
1206
1207 return 0;
1208}
1209
1210/*
1211 * dead roots are old snapshots that need to be deleted. This allocates
1212 * a dirty root struct and adds it into the list of dead roots that need to
1213 * be deleted
1214 */
1215void btrfs_add_dead_root(struct btrfs_root *root)
1216{
1217 struct btrfs_fs_info *fs_info = root->fs_info;
1218
1219 spin_lock(&fs_info->trans_lock);
1220 if (list_empty(&root->root_list))
1221 list_add_tail(&root->root_list, &fs_info->dead_roots);
1222 spin_unlock(&fs_info->trans_lock);
1223}
1224
1225/*
1226 * update all the cowonly tree roots on disk
1227 */
1228static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1229{
1230 struct btrfs_fs_info *fs_info = trans->fs_info;
1231 struct btrfs_root *gang[8];
1232 int i;
1233 int ret;
1234 int err = 0;
1235
1236 spin_lock(&fs_info->fs_roots_radix_lock);
1237 while (1) {
1238 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1239 (void **)gang, 0,
1240 ARRAY_SIZE(gang),
1241 BTRFS_ROOT_TRANS_TAG);
1242 if (ret == 0)
1243 break;
1244 for (i = 0; i < ret; i++) {
1245 struct btrfs_root *root = gang[i];
1246 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1247 (unsigned long)root->root_key.objectid,
1248 BTRFS_ROOT_TRANS_TAG);
1249 spin_unlock(&fs_info->fs_roots_radix_lock);
1250
1251 btrfs_free_log(trans, root);
1252 btrfs_update_reloc_root(trans, root);
1253 btrfs_orphan_commit_root(trans, root);
1254
1255 btrfs_save_ino_cache(root, trans);
1256
1257 /* see comments in should_cow_block() */
1258 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1259 smp_mb__after_atomic();
1260
1261 if (root->commit_root != root->node) {
1262 list_add_tail(&root->dirty_list,
1263 &trans->transaction->switch_commits);
1264 btrfs_set_root_node(&root->root_item,
1265 root->node);
1266 }
1267
1268 err = btrfs_update_root(trans, fs_info->tree_root,
1269 &root->root_key,
1270 &root->root_item);
1271 spin_lock(&fs_info->fs_roots_radix_lock);
1272 if (err)
1273 break;
1274 btrfs_qgroup_free_meta_all_pertrans(root);
1275 }
1276 }
1277 spin_unlock(&fs_info->fs_roots_radix_lock);
1278 return err;
1279}
1280
1281/*
1282 * defrag a given btree.
1283 * Every leaf in the btree is read and defragged.
1284 */
1285int btrfs_defrag_root(struct btrfs_root *root)
1286{
1287 struct btrfs_fs_info *info = root->fs_info;
1288 struct btrfs_trans_handle *trans;
1289 int ret;
1290
1291 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1292 return 0;
1293
1294 while (1) {
1295 trans = btrfs_start_transaction(root, 0);
1296 if (IS_ERR(trans))
1297 return PTR_ERR(trans);
1298
1299 ret = btrfs_defrag_leaves(trans, root);
1300
1301 btrfs_end_transaction(trans);
1302 btrfs_btree_balance_dirty(info);
1303 cond_resched();
1304
1305 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1306 break;
1307
1308 if (btrfs_defrag_cancelled(info)) {
1309 btrfs_debug(info, "defrag_root cancelled");
1310 ret = -EAGAIN;
1311 break;
1312 }
1313 }
1314 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1315 return ret;
1316}
1317
1318/*
1319 * Do all special snapshot related qgroup dirty hack.
1320 *
1321 * Will do all needed qgroup inherit and dirty hack like switch commit
1322 * roots inside one transaction and write all btree into disk, to make
1323 * qgroup works.
1324 */
1325static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1326 struct btrfs_root *src,
1327 struct btrfs_root *parent,
1328 struct btrfs_qgroup_inherit *inherit,
1329 u64 dst_objectid)
1330{
1331 struct btrfs_fs_info *fs_info = src->fs_info;
1332 int ret;
1333
1334 /*
1335 * Save some performance in the case that qgroups are not
1336 * enabled. If this check races with the ioctl, rescan will
1337 * kick in anyway.
1338 */
1339 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1340 return 0;
1341
1342 /*
1343 * Ensure dirty @src will be commited. Or, after comming
1344 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1345 * recorded root will never be updated again, causing an outdated root
1346 * item.
1347 */
1348 record_root_in_trans(trans, src, 1);
1349
1350 /*
1351 * We are going to commit transaction, see btrfs_commit_transaction()
1352 * comment for reason locking tree_log_mutex
1353 */
1354 mutex_lock(&fs_info->tree_log_mutex);
1355
1356 ret = commit_fs_roots(trans);
1357 if (ret)
1358 goto out;
1359 ret = btrfs_qgroup_account_extents(trans);
1360 if (ret < 0)
1361 goto out;
1362
1363 /* Now qgroup are all updated, we can inherit it to new qgroups */
1364 ret = btrfs_qgroup_inherit(trans, fs_info,
1365 src->root_key.objectid, dst_objectid,
1366 inherit);
1367 if (ret < 0)
1368 goto out;
1369
1370 /*
1371 * Now we do a simplified commit transaction, which will:
1372 * 1) commit all subvolume and extent tree
1373 * To ensure all subvolume and extent tree have a valid
1374 * commit_root to accounting later insert_dir_item()
1375 * 2) write all btree blocks onto disk
1376 * This is to make sure later btree modification will be cowed
1377 * Or commit_root can be populated and cause wrong qgroup numbers
1378 * In this simplified commit, we don't really care about other trees
1379 * like chunk and root tree, as they won't affect qgroup.
1380 * And we don't write super to avoid half committed status.
1381 */
1382 ret = commit_cowonly_roots(trans);
1383 if (ret)
1384 goto out;
1385 switch_commit_roots(trans->transaction);
1386 ret = btrfs_write_and_wait_transaction(trans);
1387 if (ret)
1388 btrfs_handle_fs_error(fs_info, ret,
1389 "Error while writing out transaction for qgroup");
1390
1391out:
1392 mutex_unlock(&fs_info->tree_log_mutex);
1393
1394 /*
1395 * Force parent root to be updated, as we recorded it before so its
1396 * last_trans == cur_transid.
1397 * Or it won't be committed again onto disk after later
1398 * insert_dir_item()
1399 */
1400 if (!ret)
1401 record_root_in_trans(trans, parent, 1);
1402 return ret;
1403}
1404
1405/*
1406 * new snapshots need to be created at a very specific time in the
1407 * transaction commit. This does the actual creation.
1408 *
1409 * Note:
1410 * If the error which may affect the commitment of the current transaction
1411 * happens, we should return the error number. If the error which just affect
1412 * the creation of the pending snapshots, just return 0.
1413 */
1414static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1415 struct btrfs_pending_snapshot *pending)
1416{
1417
1418 struct btrfs_fs_info *fs_info = trans->fs_info;
1419 struct btrfs_key key;
1420 struct btrfs_root_item *new_root_item;
1421 struct btrfs_root *tree_root = fs_info->tree_root;
1422 struct btrfs_root *root = pending->root;
1423 struct btrfs_root *parent_root;
1424 struct btrfs_block_rsv *rsv;
1425 struct inode *parent_inode;
1426 struct btrfs_path *path;
1427 struct btrfs_dir_item *dir_item;
1428 struct dentry *dentry;
1429 struct extent_buffer *tmp;
1430 struct extent_buffer *old;
1431 struct timespec cur_time;
1432 int ret = 0;
1433 u64 to_reserve = 0;
1434 u64 index = 0;
1435 u64 objectid;
1436 u64 root_flags;
1437 uuid_le new_uuid;
1438
1439 ASSERT(pending->path);
1440 path = pending->path;
1441
1442 ASSERT(pending->root_item);
1443 new_root_item = pending->root_item;
1444
1445 pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1446 if (pending->error)
1447 goto no_free_objectid;
1448
1449 /*
1450 * Make qgroup to skip current new snapshot's qgroupid, as it is
1451 * accounted by later btrfs_qgroup_inherit().
1452 */
1453 btrfs_set_skip_qgroup(trans, objectid);
1454
1455 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1456
1457 if (to_reserve > 0) {
1458 pending->error = btrfs_block_rsv_add(root,
1459 &pending->block_rsv,
1460 to_reserve,
1461 BTRFS_RESERVE_NO_FLUSH);
1462 if (pending->error)
1463 goto clear_skip_qgroup;
1464 }
1465
1466 key.objectid = objectid;
1467 key.offset = (u64)-1;
1468 key.type = BTRFS_ROOT_ITEM_KEY;
1469
1470 rsv = trans->block_rsv;
1471 trans->block_rsv = &pending->block_rsv;
1472 trans->bytes_reserved = trans->block_rsv->reserved;
1473 trace_btrfs_space_reservation(fs_info, "transaction",
1474 trans->transid,
1475 trans->bytes_reserved, 1);
1476 dentry = pending->dentry;
1477 parent_inode = pending->dir;
1478 parent_root = BTRFS_I(parent_inode)->root;
1479 record_root_in_trans(trans, parent_root, 0);
1480
1481 cur_time = current_time(parent_inode);
1482
1483 /*
1484 * insert the directory item
1485 */
1486 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1487 BUG_ON(ret); /* -ENOMEM */
1488
1489 /* check if there is a file/dir which has the same name. */
1490 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1491 btrfs_ino(BTRFS_I(parent_inode)),
1492 dentry->d_name.name,
1493 dentry->d_name.len, 0);
1494 if (dir_item != NULL && !IS_ERR(dir_item)) {
1495 pending->error = -EEXIST;
1496 goto dir_item_existed;
1497 } else if (IS_ERR(dir_item)) {
1498 ret = PTR_ERR(dir_item);
1499 btrfs_abort_transaction(trans, ret);
1500 goto fail;
1501 }
1502 btrfs_release_path(path);
1503
1504 /*
1505 * pull in the delayed directory update
1506 * and the delayed inode item
1507 * otherwise we corrupt the FS during
1508 * snapshot
1509 */
1510 ret = btrfs_run_delayed_items(trans);
1511 if (ret) { /* Transaction aborted */
1512 btrfs_abort_transaction(trans, ret);
1513 goto fail;
1514 }
1515
1516 record_root_in_trans(trans, root, 0);
1517 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1518 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1519 btrfs_check_and_init_root_item(new_root_item);
1520
1521 root_flags = btrfs_root_flags(new_root_item);
1522 if (pending->readonly)
1523 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1524 else
1525 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1526 btrfs_set_root_flags(new_root_item, root_flags);
1527
1528 btrfs_set_root_generation_v2(new_root_item,
1529 trans->transid);
1530 uuid_le_gen(&new_uuid);
1531 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1532 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1533 BTRFS_UUID_SIZE);
1534 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1535 memset(new_root_item->received_uuid, 0,
1536 sizeof(new_root_item->received_uuid));
1537 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1538 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1539 btrfs_set_root_stransid(new_root_item, 0);
1540 btrfs_set_root_rtransid(new_root_item, 0);
1541 }
1542 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1543 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1544 btrfs_set_root_otransid(new_root_item, trans->transid);
1545
1546 old = btrfs_lock_root_node(root);
1547 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1548 if (ret) {
1549 btrfs_tree_unlock(old);
1550 free_extent_buffer(old);
1551 btrfs_abort_transaction(trans, ret);
1552 goto fail;
1553 }
1554
1555 btrfs_set_lock_blocking(old);
1556
1557 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1558 /* clean up in any case */
1559 btrfs_tree_unlock(old);
1560 free_extent_buffer(old);
1561 if (ret) {
1562 btrfs_abort_transaction(trans, ret);
1563 goto fail;
1564 }
1565 /* see comments in should_cow_block() */
1566 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1567 smp_wmb();
1568
1569 btrfs_set_root_node(new_root_item, tmp);
1570 /* record when the snapshot was created in key.offset */
1571 key.offset = trans->transid;
1572 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1573 btrfs_tree_unlock(tmp);
1574 free_extent_buffer(tmp);
1575 if (ret) {
1576 btrfs_abort_transaction(trans, ret);
1577 goto fail;
1578 }
1579
1580 /*
1581 * insert root back/forward references
1582 */
1583 ret = btrfs_add_root_ref(trans, fs_info, objectid,
1584 parent_root->root_key.objectid,
1585 btrfs_ino(BTRFS_I(parent_inode)), index,
1586 dentry->d_name.name, dentry->d_name.len);
1587 if (ret) {
1588 btrfs_abort_transaction(trans, ret);
1589 goto fail;
1590 }
1591
1592 key.offset = (u64)-1;
1593 pending->snap = btrfs_read_fs_root_no_name(fs_info, &key);
1594 if (IS_ERR(pending->snap)) {
1595 ret = PTR_ERR(pending->snap);
1596 btrfs_abort_transaction(trans, ret);
1597 goto fail;
1598 }
1599
1600 ret = btrfs_reloc_post_snapshot(trans, pending);
1601 if (ret) {
1602 btrfs_abort_transaction(trans, ret);
1603 goto fail;
1604 }
1605
1606 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1607 if (ret) {
1608 btrfs_abort_transaction(trans, ret);
1609 goto fail;
1610 }
1611
1612 /*
1613 * Do special qgroup accounting for snapshot, as we do some qgroup
1614 * snapshot hack to do fast snapshot.
1615 * To co-operate with that hack, we do hack again.
1616 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1617 */
1618 ret = qgroup_account_snapshot(trans, root, parent_root,
1619 pending->inherit, objectid);
1620 if (ret < 0)
1621 goto fail;
1622
1623 ret = btrfs_insert_dir_item(trans, parent_root,
1624 dentry->d_name.name, dentry->d_name.len,
1625 BTRFS_I(parent_inode), &key,
1626 BTRFS_FT_DIR, index);
1627 /* We have check then name at the beginning, so it is impossible. */
1628 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1629 if (ret) {
1630 btrfs_abort_transaction(trans, ret);
1631 goto fail;
1632 }
1633
1634 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1635 dentry->d_name.len * 2);
1636 parent_inode->i_mtime = parent_inode->i_ctime =
1637 current_time(parent_inode);
1638 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1639 if (ret) {
1640 btrfs_abort_transaction(trans, ret);
1641 goto fail;
1642 }
1643 ret = btrfs_uuid_tree_add(trans, fs_info, new_uuid.b,
1644 BTRFS_UUID_KEY_SUBVOL, objectid);
1645 if (ret) {
1646 btrfs_abort_transaction(trans, ret);
1647 goto fail;
1648 }
1649 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1650 ret = btrfs_uuid_tree_add(trans, fs_info,
1651 new_root_item->received_uuid,
1652 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1653 objectid);
1654 if (ret && ret != -EEXIST) {
1655 btrfs_abort_transaction(trans, ret);
1656 goto fail;
1657 }
1658 }
1659
1660 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1661 if (ret) {
1662 btrfs_abort_transaction(trans, ret);
1663 goto fail;
1664 }
1665
1666fail:
1667 pending->error = ret;
1668dir_item_existed:
1669 trans->block_rsv = rsv;
1670 trans->bytes_reserved = 0;
1671clear_skip_qgroup:
1672 btrfs_clear_skip_qgroup(trans);
1673no_free_objectid:
1674 kfree(new_root_item);
1675 pending->root_item = NULL;
1676 btrfs_free_path(path);
1677 pending->path = NULL;
1678
1679 return ret;
1680}
1681
1682/*
1683 * create all the snapshots we've scheduled for creation
1684 */
1685static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1686{
1687 struct btrfs_pending_snapshot *pending, *next;
1688 struct list_head *head = &trans->transaction->pending_snapshots;
1689 int ret = 0;
1690
1691 list_for_each_entry_safe(pending, next, head, list) {
1692 list_del(&pending->list);
1693 ret = create_pending_snapshot(trans, pending);
1694 if (ret)
1695 break;
1696 }
1697 return ret;
1698}
1699
1700static void update_super_roots(struct btrfs_fs_info *fs_info)
1701{
1702 struct btrfs_root_item *root_item;
1703 struct btrfs_super_block *super;
1704
1705 super = fs_info->super_copy;
1706
1707 root_item = &fs_info->chunk_root->root_item;
1708 super->chunk_root = root_item->bytenr;
1709 super->chunk_root_generation = root_item->generation;
1710 super->chunk_root_level = root_item->level;
1711
1712 root_item = &fs_info->tree_root->root_item;
1713 super->root = root_item->bytenr;
1714 super->generation = root_item->generation;
1715 super->root_level = root_item->level;
1716 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1717 super->cache_generation = root_item->generation;
1718 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1719 super->uuid_tree_generation = root_item->generation;
1720}
1721
1722int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1723{
1724 struct btrfs_transaction *trans;
1725 int ret = 0;
1726
1727 spin_lock(&info->trans_lock);
1728 trans = info->running_transaction;
1729 if (trans)
1730 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1731 spin_unlock(&info->trans_lock);
1732 return ret;
1733}
1734
1735int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1736{
1737 struct btrfs_transaction *trans;
1738 int ret = 0;
1739
1740 spin_lock(&info->trans_lock);
1741 trans = info->running_transaction;
1742 if (trans)
1743 ret = is_transaction_blocked(trans);
1744 spin_unlock(&info->trans_lock);
1745 return ret;
1746}
1747
1748/*
1749 * wait for the current transaction commit to start and block subsequent
1750 * transaction joins
1751 */
1752static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info,
1753 struct btrfs_transaction *trans)
1754{
1755 wait_event(fs_info->transaction_blocked_wait,
1756 trans->state >= TRANS_STATE_COMMIT_START || trans->aborted);
1757}
1758
1759/*
1760 * wait for the current transaction to start and then become unblocked.
1761 * caller holds ref.
1762 */
1763static void wait_current_trans_commit_start_and_unblock(
1764 struct btrfs_fs_info *fs_info,
1765 struct btrfs_transaction *trans)
1766{
1767 wait_event(fs_info->transaction_wait,
1768 trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted);
1769}
1770
1771/*
1772 * commit transactions asynchronously. once btrfs_commit_transaction_async
1773 * returns, any subsequent transaction will not be allowed to join.
1774 */
1775struct btrfs_async_commit {
1776 struct btrfs_trans_handle *newtrans;
1777 struct work_struct work;
1778};
1779
1780static void do_async_commit(struct work_struct *work)
1781{
1782 struct btrfs_async_commit *ac =
1783 container_of(work, struct btrfs_async_commit, work);
1784
1785 /*
1786 * We've got freeze protection passed with the transaction.
1787 * Tell lockdep about it.
1788 */
1789 if (ac->newtrans->type & __TRANS_FREEZABLE)
1790 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
1791
1792 current->journal_info = ac->newtrans;
1793
1794 btrfs_commit_transaction(ac->newtrans);
1795 kfree(ac);
1796}
1797
1798int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1799 int wait_for_unblock)
1800{
1801 struct btrfs_fs_info *fs_info = trans->fs_info;
1802 struct btrfs_async_commit *ac;
1803 struct btrfs_transaction *cur_trans;
1804
1805 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1806 if (!ac)
1807 return -ENOMEM;
1808
1809 INIT_WORK(&ac->work, do_async_commit);
1810 ac->newtrans = btrfs_join_transaction(trans->root);
1811 if (IS_ERR(ac->newtrans)) {
1812 int err = PTR_ERR(ac->newtrans);
1813 kfree(ac);
1814 return err;
1815 }
1816
1817 /* take transaction reference */
1818 cur_trans = trans->transaction;
1819 refcount_inc(&cur_trans->use_count);
1820
1821 btrfs_end_transaction(trans);
1822
1823 /*
1824 * Tell lockdep we've released the freeze rwsem, since the
1825 * async commit thread will be the one to unlock it.
1826 */
1827 if (ac->newtrans->type & __TRANS_FREEZABLE)
1828 __sb_writers_release(fs_info->sb, SB_FREEZE_FS);
1829
1830 schedule_work(&ac->work);
1831
1832 /* wait for transaction to start and unblock */
1833 if (wait_for_unblock)
1834 wait_current_trans_commit_start_and_unblock(fs_info, cur_trans);
1835 else
1836 wait_current_trans_commit_start(fs_info, cur_trans);
1837
1838 if (current->journal_info == trans)
1839 current->journal_info = NULL;
1840
1841 btrfs_put_transaction(cur_trans);
1842 return 0;
1843}
1844
1845
1846static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1847{
1848 struct btrfs_fs_info *fs_info = trans->fs_info;
1849 struct btrfs_transaction *cur_trans = trans->transaction;
1850 DEFINE_WAIT(wait);
1851
1852 WARN_ON(refcount_read(&trans->use_count) > 1);
1853
1854 btrfs_abort_transaction(trans, err);
1855
1856 spin_lock(&fs_info->trans_lock);
1857
1858 /*
1859 * If the transaction is removed from the list, it means this
1860 * transaction has been committed successfully, so it is impossible
1861 * to call the cleanup function.
1862 */
1863 BUG_ON(list_empty(&cur_trans->list));
1864
1865 list_del_init(&cur_trans->list);
1866 if (cur_trans == fs_info->running_transaction) {
1867 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1868 spin_unlock(&fs_info->trans_lock);
1869 wait_event(cur_trans->writer_wait,
1870 atomic_read(&cur_trans->num_writers) == 1);
1871
1872 spin_lock(&fs_info->trans_lock);
1873 }
1874 spin_unlock(&fs_info->trans_lock);
1875
1876 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
1877
1878 spin_lock(&fs_info->trans_lock);
1879 if (cur_trans == fs_info->running_transaction)
1880 fs_info->running_transaction = NULL;
1881 spin_unlock(&fs_info->trans_lock);
1882
1883 if (trans->type & __TRANS_FREEZABLE)
1884 sb_end_intwrite(fs_info->sb);
1885 btrfs_put_transaction(cur_trans);
1886 btrfs_put_transaction(cur_trans);
1887
1888 trace_btrfs_transaction_commit(trans->root);
1889
1890 if (current->journal_info == trans)
1891 current->journal_info = NULL;
1892 btrfs_scrub_cancel(fs_info);
1893
1894 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1895}
1896
1897static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1898{
1899 /*
1900 * We use writeback_inodes_sb here because if we used
1901 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
1902 * Currently are holding the fs freeze lock, if we do an async flush
1903 * we'll do btrfs_join_transaction() and deadlock because we need to
1904 * wait for the fs freeze lock. Using the direct flushing we benefit
1905 * from already being in a transaction and our join_transaction doesn't
1906 * have to re-take the fs freeze lock.
1907 */
1908 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1909 writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
1910 return 0;
1911}
1912
1913static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1914{
1915 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1916 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
1917}
1918
1919static inline void
1920btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans)
1921{
1922 wait_event(cur_trans->pending_wait,
1923 atomic_read(&cur_trans->pending_ordered) == 0);
1924}
1925
1926int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
1927{
1928 struct btrfs_fs_info *fs_info = trans->fs_info;
1929 struct btrfs_transaction *cur_trans = trans->transaction;
1930 struct btrfs_transaction *prev_trans = NULL;
1931 int ret;
1932
1933 /* Stop the commit early if ->aborted is set */
1934 if (unlikely(READ_ONCE(cur_trans->aborted))) {
1935 ret = cur_trans->aborted;
1936 btrfs_end_transaction(trans);
1937 return ret;
1938 }
1939
1940 /* make a pass through all the delayed refs we have so far
1941 * any runnings procs may add more while we are here
1942 */
1943 ret = btrfs_run_delayed_refs(trans, 0);
1944 if (ret) {
1945 btrfs_end_transaction(trans);
1946 return ret;
1947 }
1948
1949 btrfs_trans_release_metadata(trans);
1950 trans->block_rsv = NULL;
1951
1952 cur_trans = trans->transaction;
1953
1954 /*
1955 * set the flushing flag so procs in this transaction have to
1956 * start sending their work down.
1957 */
1958 cur_trans->delayed_refs.flushing = 1;
1959 smp_wmb();
1960
1961 if (!list_empty(&trans->new_bgs))
1962 btrfs_create_pending_block_groups(trans);
1963
1964 ret = btrfs_run_delayed_refs(trans, 0);
1965 if (ret) {
1966 btrfs_end_transaction(trans);
1967 return ret;
1968 }
1969
1970 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
1971 int run_it = 0;
1972
1973 /* this mutex is also taken before trying to set
1974 * block groups readonly. We need to make sure
1975 * that nobody has set a block group readonly
1976 * after a extents from that block group have been
1977 * allocated for cache files. btrfs_set_block_group_ro
1978 * will wait for the transaction to commit if it
1979 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
1980 *
1981 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
1982 * only one process starts all the block group IO. It wouldn't
1983 * hurt to have more than one go through, but there's no
1984 * real advantage to it either.
1985 */
1986 mutex_lock(&fs_info->ro_block_group_mutex);
1987 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
1988 &cur_trans->flags))
1989 run_it = 1;
1990 mutex_unlock(&fs_info->ro_block_group_mutex);
1991
1992 if (run_it) {
1993 ret = btrfs_start_dirty_block_groups(trans);
1994 if (ret) {
1995 btrfs_end_transaction(trans);
1996 return ret;
1997 }
1998 }
1999 }
2000
2001 spin_lock(&fs_info->trans_lock);
2002 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2003 spin_unlock(&fs_info->trans_lock);
2004 refcount_inc(&cur_trans->use_count);
2005 ret = btrfs_end_transaction(trans);
2006
2007 wait_for_commit(cur_trans);
2008
2009 if (unlikely(cur_trans->aborted))
2010 ret = cur_trans->aborted;
2011
2012 btrfs_put_transaction(cur_trans);
2013
2014 return ret;
2015 }
2016
2017 cur_trans->state = TRANS_STATE_COMMIT_START;
2018 wake_up(&fs_info->transaction_blocked_wait);
2019
2020 if (cur_trans->list.prev != &fs_info->trans_list) {
2021 prev_trans = list_entry(cur_trans->list.prev,
2022 struct btrfs_transaction, list);
2023 if (prev_trans->state != TRANS_STATE_COMPLETED) {
2024 refcount_inc(&prev_trans->use_count);
2025 spin_unlock(&fs_info->trans_lock);
2026
2027 wait_for_commit(prev_trans);
2028 ret = prev_trans->aborted;
2029
2030 btrfs_put_transaction(prev_trans);
2031 if (ret)
2032 goto cleanup_transaction;
2033 } else {
2034 spin_unlock(&fs_info->trans_lock);
2035 }
2036 } else {
2037 spin_unlock(&fs_info->trans_lock);
2038 }
2039
2040 extwriter_counter_dec(cur_trans, trans->type);
2041
2042 ret = btrfs_start_delalloc_flush(fs_info);
2043 if (ret)
2044 goto cleanup_transaction;
2045
2046 ret = btrfs_run_delayed_items(trans);
2047 if (ret)
2048 goto cleanup_transaction;
2049
2050 wait_event(cur_trans->writer_wait,
2051 extwriter_counter_read(cur_trans) == 0);
2052
2053 /* some pending stuffs might be added after the previous flush. */
2054 ret = btrfs_run_delayed_items(trans);
2055 if (ret)
2056 goto cleanup_transaction;
2057
2058 btrfs_wait_delalloc_flush(fs_info);
2059
2060 btrfs_wait_pending_ordered(cur_trans);
2061
2062 btrfs_scrub_pause(fs_info);
2063 /*
2064 * Ok now we need to make sure to block out any other joins while we
2065 * commit the transaction. We could have started a join before setting
2066 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2067 */
2068 spin_lock(&fs_info->trans_lock);
2069 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2070 spin_unlock(&fs_info->trans_lock);
2071 wait_event(cur_trans->writer_wait,
2072 atomic_read(&cur_trans->num_writers) == 1);
2073
2074 /* ->aborted might be set after the previous check, so check it */
2075 if (unlikely(READ_ONCE(cur_trans->aborted))) {
2076 ret = cur_trans->aborted;
2077 goto scrub_continue;
2078 }
2079 /*
2080 * the reloc mutex makes sure that we stop
2081 * the balancing code from coming in and moving
2082 * extents around in the middle of the commit
2083 */
2084 mutex_lock(&fs_info->reloc_mutex);
2085
2086 /*
2087 * We needn't worry about the delayed items because we will
2088 * deal with them in create_pending_snapshot(), which is the
2089 * core function of the snapshot creation.
2090 */
2091 ret = create_pending_snapshots(trans);
2092 if (ret) {
2093 mutex_unlock(&fs_info->reloc_mutex);
2094 goto scrub_continue;
2095 }
2096
2097 /*
2098 * We insert the dir indexes of the snapshots and update the inode
2099 * of the snapshots' parents after the snapshot creation, so there
2100 * are some delayed items which are not dealt with. Now deal with
2101 * them.
2102 *
2103 * We needn't worry that this operation will corrupt the snapshots,
2104 * because all the tree which are snapshoted will be forced to COW
2105 * the nodes and leaves.
2106 */
2107 ret = btrfs_run_delayed_items(trans);
2108 if (ret) {
2109 mutex_unlock(&fs_info->reloc_mutex);
2110 goto scrub_continue;
2111 }
2112
2113 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2114 if (ret) {
2115 mutex_unlock(&fs_info->reloc_mutex);
2116 goto scrub_continue;
2117 }
2118
2119 /*
2120 * make sure none of the code above managed to slip in a
2121 * delayed item
2122 */
2123 btrfs_assert_delayed_root_empty(fs_info);
2124
2125 WARN_ON(cur_trans != trans->transaction);
2126
2127 /* btrfs_commit_tree_roots is responsible for getting the
2128 * various roots consistent with each other. Every pointer
2129 * in the tree of tree roots has to point to the most up to date
2130 * root for every subvolume and other tree. So, we have to keep
2131 * the tree logging code from jumping in and changing any
2132 * of the trees.
2133 *
2134 * At this point in the commit, there can't be any tree-log
2135 * writers, but a little lower down we drop the trans mutex
2136 * and let new people in. By holding the tree_log_mutex
2137 * from now until after the super is written, we avoid races
2138 * with the tree-log code.
2139 */
2140 mutex_lock(&fs_info->tree_log_mutex);
2141
2142 ret = commit_fs_roots(trans);
2143 if (ret) {
2144 mutex_unlock(&fs_info->tree_log_mutex);
2145 mutex_unlock(&fs_info->reloc_mutex);
2146 goto scrub_continue;
2147 }
2148
2149 /*
2150 * Since the transaction is done, we can apply the pending changes
2151 * before the next transaction.
2152 */
2153 btrfs_apply_pending_changes(fs_info);
2154
2155 /* commit_fs_roots gets rid of all the tree log roots, it is now
2156 * safe to free the root of tree log roots
2157 */
2158 btrfs_free_log_root_tree(trans, fs_info);
2159
2160 /*
2161 * commit_fs_roots() can call btrfs_save_ino_cache(), which generates
2162 * new delayed refs. Must handle them or qgroup can be wrong.
2163 */
2164 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2165 if (ret) {
2166 mutex_unlock(&fs_info->tree_log_mutex);
2167 mutex_unlock(&fs_info->reloc_mutex);
2168 goto scrub_continue;
2169 }
2170
2171 /*
2172 * Since fs roots are all committed, we can get a quite accurate
2173 * new_roots. So let's do quota accounting.
2174 */
2175 ret = btrfs_qgroup_account_extents(trans);
2176 if (ret < 0) {
2177 mutex_unlock(&fs_info->tree_log_mutex);
2178 mutex_unlock(&fs_info->reloc_mutex);
2179 goto scrub_continue;
2180 }
2181
2182 ret = commit_cowonly_roots(trans);
2183 if (ret) {
2184 mutex_unlock(&fs_info->tree_log_mutex);
2185 mutex_unlock(&fs_info->reloc_mutex);
2186 goto scrub_continue;
2187 }
2188
2189 /*
2190 * The tasks which save the space cache and inode cache may also
2191 * update ->aborted, check it.
2192 */
2193 if (unlikely(READ_ONCE(cur_trans->aborted))) {
2194 ret = cur_trans->aborted;
2195 mutex_unlock(&fs_info->tree_log_mutex);
2196 mutex_unlock(&fs_info->reloc_mutex);
2197 goto scrub_continue;
2198 }
2199
2200 btrfs_prepare_extent_commit(fs_info);
2201
2202 cur_trans = fs_info->running_transaction;
2203
2204 btrfs_set_root_node(&fs_info->tree_root->root_item,
2205 fs_info->tree_root->node);
2206 list_add_tail(&fs_info->tree_root->dirty_list,
2207 &cur_trans->switch_commits);
2208
2209 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2210 fs_info->chunk_root->node);
2211 list_add_tail(&fs_info->chunk_root->dirty_list,
2212 &cur_trans->switch_commits);
2213
2214 switch_commit_roots(cur_trans);
2215
2216 ASSERT(list_empty(&cur_trans->dirty_bgs));
2217 ASSERT(list_empty(&cur_trans->io_bgs));
2218 update_super_roots(fs_info);
2219
2220 btrfs_set_super_log_root(fs_info->super_copy, 0);
2221 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2222 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2223 sizeof(*fs_info->super_copy));
2224
2225 btrfs_update_commit_device_size(fs_info);
2226 btrfs_update_commit_device_bytes_used(cur_trans);
2227
2228 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2229 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2230
2231 btrfs_trans_release_chunk_metadata(trans);
2232
2233 spin_lock(&fs_info->trans_lock);
2234 cur_trans->state = TRANS_STATE_UNBLOCKED;
2235 fs_info->running_transaction = NULL;
2236 spin_unlock(&fs_info->trans_lock);
2237 mutex_unlock(&fs_info->reloc_mutex);
2238
2239 wake_up(&fs_info->transaction_wait);
2240
2241 ret = btrfs_write_and_wait_transaction(trans);
2242 if (ret) {
2243 btrfs_handle_fs_error(fs_info, ret,
2244 "Error while writing out transaction");
2245 mutex_unlock(&fs_info->tree_log_mutex);
2246 goto scrub_continue;
2247 }
2248
2249 ret = write_all_supers(fs_info, 0);
2250 /*
2251 * the super is written, we can safely allow the tree-loggers
2252 * to go about their business
2253 */
2254 mutex_unlock(&fs_info->tree_log_mutex);
2255 if (ret)
2256 goto scrub_continue;
2257
2258 btrfs_finish_extent_commit(trans);
2259
2260 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2261 btrfs_clear_space_info_full(fs_info);
2262
2263 fs_info->last_trans_committed = cur_trans->transid;
2264 /*
2265 * We needn't acquire the lock here because there is no other task
2266 * which can change it.
2267 */
2268 cur_trans->state = TRANS_STATE_COMPLETED;
2269 wake_up(&cur_trans->commit_wait);
2270 clear_bit(BTRFS_FS_NEED_ASYNC_COMMIT, &fs_info->flags);
2271
2272 spin_lock(&fs_info->trans_lock);
2273 list_del_init(&cur_trans->list);
2274 spin_unlock(&fs_info->trans_lock);
2275
2276 btrfs_put_transaction(cur_trans);
2277 btrfs_put_transaction(cur_trans);
2278
2279 if (trans->type & __TRANS_FREEZABLE)
2280 sb_end_intwrite(fs_info->sb);
2281
2282 trace_btrfs_transaction_commit(trans->root);
2283
2284 btrfs_scrub_continue(fs_info);
2285
2286 if (current->journal_info == trans)
2287 current->journal_info = NULL;
2288
2289 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2290
2291 /*
2292 * If fs has been frozen, we can not handle delayed iputs, otherwise
2293 * it'll result in deadlock about SB_FREEZE_FS.
2294 */
2295 if (current != fs_info->transaction_kthread &&
2296 current != fs_info->cleaner_kthread &&
2297 !test_bit(BTRFS_FS_FROZEN, &fs_info->flags))
2298 btrfs_run_delayed_iputs(fs_info);
2299
2300 return ret;
2301
2302scrub_continue:
2303 btrfs_scrub_continue(fs_info);
2304cleanup_transaction:
2305 btrfs_trans_release_metadata(trans);
2306 btrfs_trans_release_chunk_metadata(trans);
2307 trans->block_rsv = NULL;
2308 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2309 if (current->journal_info == trans)
2310 current->journal_info = NULL;
2311 cleanup_transaction(trans, ret);
2312
2313 return ret;
2314}
2315
2316/*
2317 * return < 0 if error
2318 * 0 if there are no more dead_roots at the time of call
2319 * 1 there are more to be processed, call me again
2320 *
2321 * The return value indicates there are certainly more snapshots to delete, but
2322 * if there comes a new one during processing, it may return 0. We don't mind,
2323 * because btrfs_commit_super will poke cleaner thread and it will process it a
2324 * few seconds later.
2325 */
2326int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2327{
2328 int ret;
2329 struct btrfs_fs_info *fs_info = root->fs_info;
2330
2331 spin_lock(&fs_info->trans_lock);
2332 if (list_empty(&fs_info->dead_roots)) {
2333 spin_unlock(&fs_info->trans_lock);
2334 return 0;
2335 }
2336 root = list_first_entry(&fs_info->dead_roots,
2337 struct btrfs_root, root_list);
2338 list_del_init(&root->root_list);
2339 spin_unlock(&fs_info->trans_lock);
2340
2341 btrfs_debug(fs_info, "cleaner removing %llu", root->objectid);
2342
2343 btrfs_kill_all_delayed_nodes(root);
2344
2345 if (btrfs_header_backref_rev(root->node) <
2346 BTRFS_MIXED_BACKREF_REV)
2347 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2348 else
2349 ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2350
2351 return (ret < 0) ? 0 : 1;
2352}
2353
2354void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2355{
2356 unsigned long prev;
2357 unsigned long bit;
2358
2359 prev = xchg(&fs_info->pending_changes, 0);
2360 if (!prev)
2361 return;
2362
2363 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
2364 if (prev & bit)
2365 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2366 prev &= ~bit;
2367
2368 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
2369 if (prev & bit)
2370 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2371 prev &= ~bit;
2372
2373 bit = 1 << BTRFS_PENDING_COMMIT;
2374 if (prev & bit)
2375 btrfs_debug(fs_info, "pending commit done");
2376 prev &= ~bit;
2377
2378 if (prev)
2379 btrfs_warn(fs_info,
2380 "unknown pending changes left 0x%lx, ignoring", prev);
2381}