]> git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - fs/btrfs/transaction.c
btrfs: Remove unused arguments in tree-log.c
[mirror_ubuntu-bionic-kernel.git] / fs / btrfs / transaction.c
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 <linux/uuid.h>
26 #include "ctree.h"
27 #include "disk-io.h"
28 #include "transaction.h"
29 #include "locking.h"
30 #include "tree-log.h"
31 #include "inode-map.h"
32 #include "volumes.h"
33 #include "dev-replace.h"
34 #include "qgroup.h"
35
36 #define BTRFS_ROOT_TRANS_TAG 0
37
38 static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
39 [TRANS_STATE_RUNNING] = 0U,
40 [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE |
41 __TRANS_START),
42 [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE |
43 __TRANS_START |
44 __TRANS_ATTACH),
45 [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE |
46 __TRANS_START |
47 __TRANS_ATTACH |
48 __TRANS_JOIN),
49 [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE |
50 __TRANS_START |
51 __TRANS_ATTACH |
52 __TRANS_JOIN |
53 __TRANS_JOIN_NOLOCK),
54 [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE |
55 __TRANS_START |
56 __TRANS_ATTACH |
57 __TRANS_JOIN |
58 __TRANS_JOIN_NOLOCK),
59 };
60
61 void btrfs_put_transaction(struct btrfs_transaction *transaction)
62 {
63 WARN_ON(atomic_read(&transaction->use_count) == 0);
64 if (atomic_dec_and_test(&transaction->use_count)) {
65 BUG_ON(!list_empty(&transaction->list));
66 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
67 if (transaction->delayed_refs.pending_csums)
68 printk(KERN_ERR "pending csums is %llu\n",
69 transaction->delayed_refs.pending_csums);
70 while (!list_empty(&transaction->pending_chunks)) {
71 struct extent_map *em;
72
73 em = list_first_entry(&transaction->pending_chunks,
74 struct extent_map, list);
75 list_del_init(&em->list);
76 free_extent_map(em);
77 }
78 kmem_cache_free(btrfs_transaction_cachep, transaction);
79 }
80 }
81
82 static void clear_btree_io_tree(struct extent_io_tree *tree)
83 {
84 spin_lock(&tree->lock);
85 while (!RB_EMPTY_ROOT(&tree->state)) {
86 struct rb_node *node;
87 struct extent_state *state;
88
89 node = rb_first(&tree->state);
90 state = rb_entry(node, struct extent_state, rb_node);
91 rb_erase(&state->rb_node, &tree->state);
92 RB_CLEAR_NODE(&state->rb_node);
93 /*
94 * btree io trees aren't supposed to have tasks waiting for
95 * changes in the flags of extent states ever.
96 */
97 ASSERT(!waitqueue_active(&state->wq));
98 free_extent_state(state);
99
100 cond_resched_lock(&tree->lock);
101 }
102 spin_unlock(&tree->lock);
103 }
104
105 static noinline void switch_commit_roots(struct btrfs_transaction *trans,
106 struct btrfs_fs_info *fs_info)
107 {
108 struct btrfs_root *root, *tmp;
109
110 down_write(&fs_info->commit_root_sem);
111 list_for_each_entry_safe(root, tmp, &trans->switch_commits,
112 dirty_list) {
113 list_del_init(&root->dirty_list);
114 free_extent_buffer(root->commit_root);
115 root->commit_root = btrfs_root_node(root);
116 if (is_fstree(root->objectid))
117 btrfs_unpin_free_ino(root);
118 clear_btree_io_tree(&root->dirty_log_pages);
119 }
120 up_write(&fs_info->commit_root_sem);
121 }
122
123 static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
124 unsigned int type)
125 {
126 if (type & TRANS_EXTWRITERS)
127 atomic_inc(&trans->num_extwriters);
128 }
129
130 static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
131 unsigned int type)
132 {
133 if (type & TRANS_EXTWRITERS)
134 atomic_dec(&trans->num_extwriters);
135 }
136
137 static inline void extwriter_counter_init(struct btrfs_transaction *trans,
138 unsigned int type)
139 {
140 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
141 }
142
143 static inline int extwriter_counter_read(struct btrfs_transaction *trans)
144 {
145 return atomic_read(&trans->num_extwriters);
146 }
147
148 /*
149 * either allocate a new transaction or hop into the existing one
150 */
151 static noinline int join_transaction(struct btrfs_root *root, unsigned int type)
152 {
153 struct btrfs_transaction *cur_trans;
154 struct btrfs_fs_info *fs_info = root->fs_info;
155
156 spin_lock(&fs_info->trans_lock);
157 loop:
158 /* The file system has been taken offline. No new transactions. */
159 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
160 spin_unlock(&fs_info->trans_lock);
161 return -EROFS;
162 }
163
164 cur_trans = fs_info->running_transaction;
165 if (cur_trans) {
166 if (cur_trans->aborted) {
167 spin_unlock(&fs_info->trans_lock);
168 return cur_trans->aborted;
169 }
170 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
171 spin_unlock(&fs_info->trans_lock);
172 return -EBUSY;
173 }
174 atomic_inc(&cur_trans->use_count);
175 atomic_inc(&cur_trans->num_writers);
176 extwriter_counter_inc(cur_trans, type);
177 spin_unlock(&fs_info->trans_lock);
178 return 0;
179 }
180 spin_unlock(&fs_info->trans_lock);
181
182 /*
183 * If we are ATTACH, we just want to catch the current transaction,
184 * and commit it. If there is no transaction, just return ENOENT.
185 */
186 if (type == TRANS_ATTACH)
187 return -ENOENT;
188
189 /*
190 * JOIN_NOLOCK only happens during the transaction commit, so
191 * it is impossible that ->running_transaction is NULL
192 */
193 BUG_ON(type == TRANS_JOIN_NOLOCK);
194
195 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
196 if (!cur_trans)
197 return -ENOMEM;
198
199 spin_lock(&fs_info->trans_lock);
200 if (fs_info->running_transaction) {
201 /*
202 * someone started a transaction after we unlocked. Make sure
203 * to redo the checks above
204 */
205 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
206 goto loop;
207 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
208 spin_unlock(&fs_info->trans_lock);
209 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
210 return -EROFS;
211 }
212
213 atomic_set(&cur_trans->num_writers, 1);
214 extwriter_counter_init(cur_trans, type);
215 init_waitqueue_head(&cur_trans->writer_wait);
216 init_waitqueue_head(&cur_trans->commit_wait);
217 cur_trans->state = TRANS_STATE_RUNNING;
218 /*
219 * One for this trans handle, one so it will live on until we
220 * commit the transaction.
221 */
222 atomic_set(&cur_trans->use_count, 2);
223 cur_trans->have_free_bgs = 0;
224 cur_trans->start_time = get_seconds();
225 cur_trans->dirty_bg_run = 0;
226
227 cur_trans->delayed_refs.href_root = RB_ROOT;
228 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
229 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
230 cur_trans->delayed_refs.num_heads_ready = 0;
231 cur_trans->delayed_refs.pending_csums = 0;
232 cur_trans->delayed_refs.num_heads = 0;
233 cur_trans->delayed_refs.flushing = 0;
234 cur_trans->delayed_refs.run_delayed_start = 0;
235 cur_trans->delayed_refs.qgroup_to_skip = 0;
236
237 /*
238 * although the tree mod log is per file system and not per transaction,
239 * the log must never go across transaction boundaries.
240 */
241 smp_mb();
242 if (!list_empty(&fs_info->tree_mod_seq_list))
243 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when "
244 "creating a fresh transaction\n");
245 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
246 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when "
247 "creating a fresh transaction\n");
248 atomic64_set(&fs_info->tree_mod_seq, 0);
249
250 spin_lock_init(&cur_trans->delayed_refs.lock);
251
252 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
253 INIT_LIST_HEAD(&cur_trans->pending_chunks);
254 INIT_LIST_HEAD(&cur_trans->switch_commits);
255 INIT_LIST_HEAD(&cur_trans->pending_ordered);
256 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
257 INIT_LIST_HEAD(&cur_trans->io_bgs);
258 mutex_init(&cur_trans->cache_write_mutex);
259 cur_trans->num_dirty_bgs = 0;
260 spin_lock_init(&cur_trans->dirty_bgs_lock);
261 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
262 spin_lock_init(&cur_trans->deleted_bgs_lock);
263 list_add_tail(&cur_trans->list, &fs_info->trans_list);
264 extent_io_tree_init(&cur_trans->dirty_pages,
265 fs_info->btree_inode->i_mapping);
266 fs_info->generation++;
267 cur_trans->transid = fs_info->generation;
268 fs_info->running_transaction = cur_trans;
269 cur_trans->aborted = 0;
270 spin_unlock(&fs_info->trans_lock);
271
272 return 0;
273 }
274
275 /*
276 * this does all the record keeping required to make sure that a reference
277 * counted root is properly recorded in a given transaction. This is required
278 * to make sure the old root from before we joined the transaction is deleted
279 * when the transaction commits
280 */
281 static int record_root_in_trans(struct btrfs_trans_handle *trans,
282 struct btrfs_root *root)
283 {
284 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
285 root->last_trans < trans->transid) {
286 WARN_ON(root == root->fs_info->extent_root);
287 WARN_ON(root->commit_root != root->node);
288
289 /*
290 * see below for IN_TRANS_SETUP usage rules
291 * we have the reloc mutex held now, so there
292 * is only one writer in this function
293 */
294 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
295
296 /* make sure readers find IN_TRANS_SETUP before
297 * they find our root->last_trans update
298 */
299 smp_wmb();
300
301 spin_lock(&root->fs_info->fs_roots_radix_lock);
302 if (root->last_trans == trans->transid) {
303 spin_unlock(&root->fs_info->fs_roots_radix_lock);
304 return 0;
305 }
306 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
307 (unsigned long)root->root_key.objectid,
308 BTRFS_ROOT_TRANS_TAG);
309 spin_unlock(&root->fs_info->fs_roots_radix_lock);
310 root->last_trans = trans->transid;
311
312 /* this is pretty tricky. We don't want to
313 * take the relocation lock in btrfs_record_root_in_trans
314 * unless we're really doing the first setup for this root in
315 * this transaction.
316 *
317 * Normally we'd use root->last_trans as a flag to decide
318 * if we want to take the expensive mutex.
319 *
320 * But, we have to set root->last_trans before we
321 * init the relocation root, otherwise, we trip over warnings
322 * in ctree.c. The solution used here is to flag ourselves
323 * with root IN_TRANS_SETUP. When this is 1, we're still
324 * fixing up the reloc trees and everyone must wait.
325 *
326 * When this is zero, they can trust root->last_trans and fly
327 * through btrfs_record_root_in_trans without having to take the
328 * lock. smp_wmb() makes sure that all the writes above are
329 * done before we pop in the zero below
330 */
331 btrfs_init_reloc_root(trans, root);
332 smp_mb__before_atomic();
333 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
334 }
335 return 0;
336 }
337
338
339 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
340 struct btrfs_root *root)
341 {
342 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
343 return 0;
344
345 /*
346 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
347 * and barriers
348 */
349 smp_rmb();
350 if (root->last_trans == trans->transid &&
351 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
352 return 0;
353
354 mutex_lock(&root->fs_info->reloc_mutex);
355 record_root_in_trans(trans, root);
356 mutex_unlock(&root->fs_info->reloc_mutex);
357
358 return 0;
359 }
360
361 static inline int is_transaction_blocked(struct btrfs_transaction *trans)
362 {
363 return (trans->state >= TRANS_STATE_BLOCKED &&
364 trans->state < TRANS_STATE_UNBLOCKED &&
365 !trans->aborted);
366 }
367
368 /* wait for commit against the current transaction to become unblocked
369 * when this is done, it is safe to start a new transaction, but the current
370 * transaction might not be fully on disk.
371 */
372 static void wait_current_trans(struct btrfs_root *root)
373 {
374 struct btrfs_transaction *cur_trans;
375
376 spin_lock(&root->fs_info->trans_lock);
377 cur_trans = root->fs_info->running_transaction;
378 if (cur_trans && is_transaction_blocked(cur_trans)) {
379 atomic_inc(&cur_trans->use_count);
380 spin_unlock(&root->fs_info->trans_lock);
381
382 wait_event(root->fs_info->transaction_wait,
383 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
384 cur_trans->aborted);
385 btrfs_put_transaction(cur_trans);
386 } else {
387 spin_unlock(&root->fs_info->trans_lock);
388 }
389 }
390
391 static int may_wait_transaction(struct btrfs_root *root, int type)
392 {
393 if (root->fs_info->log_root_recovering)
394 return 0;
395
396 if (type == TRANS_USERSPACE)
397 return 1;
398
399 if (type == TRANS_START &&
400 !atomic_read(&root->fs_info->open_ioctl_trans))
401 return 1;
402
403 return 0;
404 }
405
406 static inline bool need_reserve_reloc_root(struct btrfs_root *root)
407 {
408 if (!root->fs_info->reloc_ctl ||
409 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
410 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
411 root->reloc_root)
412 return false;
413
414 return true;
415 }
416
417 static struct btrfs_trans_handle *
418 start_transaction(struct btrfs_root *root, u64 num_items, unsigned int type,
419 enum btrfs_reserve_flush_enum flush)
420 {
421 struct btrfs_trans_handle *h;
422 struct btrfs_transaction *cur_trans;
423 u64 num_bytes = 0;
424 u64 qgroup_reserved = 0;
425 bool reloc_reserved = false;
426 int ret;
427
428 /* Send isn't supposed to start transactions. */
429 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
430
431 if (test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state))
432 return ERR_PTR(-EROFS);
433
434 if (current->journal_info) {
435 WARN_ON(type & TRANS_EXTWRITERS);
436 h = current->journal_info;
437 h->use_count++;
438 WARN_ON(h->use_count > 2);
439 h->orig_rsv = h->block_rsv;
440 h->block_rsv = NULL;
441 goto got_it;
442 }
443
444 /*
445 * Do the reservation before we join the transaction so we can do all
446 * the appropriate flushing if need be.
447 */
448 if (num_items > 0 && root != root->fs_info->chunk_root) {
449 if (root->fs_info->quota_enabled &&
450 is_fstree(root->root_key.objectid)) {
451 qgroup_reserved = num_items * root->nodesize;
452 ret = btrfs_qgroup_reserve(root, qgroup_reserved);
453 if (ret)
454 return ERR_PTR(ret);
455 }
456
457 num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
458 /*
459 * Do the reservation for the relocation root creation
460 */
461 if (need_reserve_reloc_root(root)) {
462 num_bytes += root->nodesize;
463 reloc_reserved = true;
464 }
465
466 ret = btrfs_block_rsv_add(root,
467 &root->fs_info->trans_block_rsv,
468 num_bytes, flush);
469 if (ret)
470 goto reserve_fail;
471 }
472 again:
473 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
474 if (!h) {
475 ret = -ENOMEM;
476 goto alloc_fail;
477 }
478
479 /*
480 * If we are JOIN_NOLOCK we're already committing a transaction and
481 * waiting on this guy, so we don't need to do the sb_start_intwrite
482 * because we're already holding a ref. We need this because we could
483 * have raced in and did an fsync() on a file which can kick a commit
484 * and then we deadlock with somebody doing a freeze.
485 *
486 * If we are ATTACH, it means we just want to catch the current
487 * transaction and commit it, so we needn't do sb_start_intwrite().
488 */
489 if (type & __TRANS_FREEZABLE)
490 sb_start_intwrite(root->fs_info->sb);
491
492 if (may_wait_transaction(root, type))
493 wait_current_trans(root);
494
495 do {
496 ret = join_transaction(root, type);
497 if (ret == -EBUSY) {
498 wait_current_trans(root);
499 if (unlikely(type == TRANS_ATTACH))
500 ret = -ENOENT;
501 }
502 } while (ret == -EBUSY);
503
504 if (ret < 0) {
505 /* We must get the transaction if we are JOIN_NOLOCK. */
506 BUG_ON(type == TRANS_JOIN_NOLOCK);
507 goto join_fail;
508 }
509
510 cur_trans = root->fs_info->running_transaction;
511
512 h->transid = cur_trans->transid;
513 h->transaction = cur_trans;
514 h->blocks_used = 0;
515 h->bytes_reserved = 0;
516 h->chunk_bytes_reserved = 0;
517 h->root = root;
518 h->delayed_ref_updates = 0;
519 h->use_count = 1;
520 h->adding_csums = 0;
521 h->block_rsv = NULL;
522 h->orig_rsv = NULL;
523 h->aborted = 0;
524 h->qgroup_reserved = 0;
525 h->delayed_ref_elem.seq = 0;
526 h->type = type;
527 h->allocating_chunk = false;
528 h->reloc_reserved = false;
529 h->sync = false;
530 INIT_LIST_HEAD(&h->qgroup_ref_list);
531 INIT_LIST_HEAD(&h->new_bgs);
532 INIT_LIST_HEAD(&h->ordered);
533
534 smp_mb();
535 if (cur_trans->state >= TRANS_STATE_BLOCKED &&
536 may_wait_transaction(root, type)) {
537 current->journal_info = h;
538 btrfs_commit_transaction(h, root);
539 goto again;
540 }
541
542 if (num_bytes) {
543 trace_btrfs_space_reservation(root->fs_info, "transaction",
544 h->transid, num_bytes, 1);
545 h->block_rsv = &root->fs_info->trans_block_rsv;
546 h->bytes_reserved = num_bytes;
547 h->reloc_reserved = reloc_reserved;
548 }
549 h->qgroup_reserved = qgroup_reserved;
550
551 got_it:
552 btrfs_record_root_in_trans(h, root);
553
554 if (!current->journal_info && type != TRANS_USERSPACE)
555 current->journal_info = h;
556 return h;
557
558 join_fail:
559 if (type & __TRANS_FREEZABLE)
560 sb_end_intwrite(root->fs_info->sb);
561 kmem_cache_free(btrfs_trans_handle_cachep, h);
562 alloc_fail:
563 if (num_bytes)
564 btrfs_block_rsv_release(root, &root->fs_info->trans_block_rsv,
565 num_bytes);
566 reserve_fail:
567 if (qgroup_reserved)
568 btrfs_qgroup_free(root, qgroup_reserved);
569 return ERR_PTR(ret);
570 }
571
572 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
573 int num_items)
574 {
575 return start_transaction(root, num_items, TRANS_START,
576 BTRFS_RESERVE_FLUSH_ALL);
577 }
578
579 struct btrfs_trans_handle *btrfs_start_transaction_lflush(
580 struct btrfs_root *root, int num_items)
581 {
582 return start_transaction(root, num_items, TRANS_START,
583 BTRFS_RESERVE_FLUSH_LIMIT);
584 }
585
586 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
587 {
588 return start_transaction(root, 0, TRANS_JOIN, 0);
589 }
590
591 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
592 {
593 return start_transaction(root, 0, TRANS_JOIN_NOLOCK, 0);
594 }
595
596 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
597 {
598 return start_transaction(root, 0, TRANS_USERSPACE, 0);
599 }
600
601 /*
602 * btrfs_attach_transaction() - catch the running transaction
603 *
604 * It is used when we want to commit the current the transaction, but
605 * don't want to start a new one.
606 *
607 * Note: If this function return -ENOENT, it just means there is no
608 * running transaction. But it is possible that the inactive transaction
609 * is still in the memory, not fully on disk. If you hope there is no
610 * inactive transaction in the fs when -ENOENT is returned, you should
611 * invoke
612 * btrfs_attach_transaction_barrier()
613 */
614 struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
615 {
616 return start_transaction(root, 0, TRANS_ATTACH, 0);
617 }
618
619 /*
620 * btrfs_attach_transaction_barrier() - catch the running transaction
621 *
622 * It is similar to the above function, the differentia is this one
623 * will wait for all the inactive transactions until they fully
624 * complete.
625 */
626 struct btrfs_trans_handle *
627 btrfs_attach_transaction_barrier(struct btrfs_root *root)
628 {
629 struct btrfs_trans_handle *trans;
630
631 trans = start_transaction(root, 0, TRANS_ATTACH, 0);
632 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
633 btrfs_wait_for_commit(root, 0);
634
635 return trans;
636 }
637
638 /* wait for a transaction commit to be fully complete */
639 static noinline void wait_for_commit(struct btrfs_root *root,
640 struct btrfs_transaction *commit)
641 {
642 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
643 }
644
645 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
646 {
647 struct btrfs_transaction *cur_trans = NULL, *t;
648 int ret = 0;
649
650 if (transid) {
651 if (transid <= root->fs_info->last_trans_committed)
652 goto out;
653
654 /* find specified transaction */
655 spin_lock(&root->fs_info->trans_lock);
656 list_for_each_entry(t, &root->fs_info->trans_list, list) {
657 if (t->transid == transid) {
658 cur_trans = t;
659 atomic_inc(&cur_trans->use_count);
660 ret = 0;
661 break;
662 }
663 if (t->transid > transid) {
664 ret = 0;
665 break;
666 }
667 }
668 spin_unlock(&root->fs_info->trans_lock);
669
670 /*
671 * The specified transaction doesn't exist, or we
672 * raced with btrfs_commit_transaction
673 */
674 if (!cur_trans) {
675 if (transid > root->fs_info->last_trans_committed)
676 ret = -EINVAL;
677 goto out;
678 }
679 } else {
680 /* find newest transaction that is committing | committed */
681 spin_lock(&root->fs_info->trans_lock);
682 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
683 list) {
684 if (t->state >= TRANS_STATE_COMMIT_START) {
685 if (t->state == TRANS_STATE_COMPLETED)
686 break;
687 cur_trans = t;
688 atomic_inc(&cur_trans->use_count);
689 break;
690 }
691 }
692 spin_unlock(&root->fs_info->trans_lock);
693 if (!cur_trans)
694 goto out; /* nothing committing|committed */
695 }
696
697 wait_for_commit(root, cur_trans);
698 btrfs_put_transaction(cur_trans);
699 out:
700 return ret;
701 }
702
703 void btrfs_throttle(struct btrfs_root *root)
704 {
705 if (!atomic_read(&root->fs_info->open_ioctl_trans))
706 wait_current_trans(root);
707 }
708
709 static int should_end_transaction(struct btrfs_trans_handle *trans,
710 struct btrfs_root *root)
711 {
712 if (root->fs_info->global_block_rsv.space_info->full &&
713 btrfs_check_space_for_delayed_refs(trans, root))
714 return 1;
715
716 return !!btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
717 }
718
719 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
720 struct btrfs_root *root)
721 {
722 struct btrfs_transaction *cur_trans = trans->transaction;
723 int updates;
724 int err;
725
726 smp_mb();
727 if (cur_trans->state >= TRANS_STATE_BLOCKED ||
728 cur_trans->delayed_refs.flushing)
729 return 1;
730
731 updates = trans->delayed_ref_updates;
732 trans->delayed_ref_updates = 0;
733 if (updates) {
734 err = btrfs_run_delayed_refs(trans, root, updates * 2);
735 if (err) /* Error code will also eval true */
736 return err;
737 }
738
739 return should_end_transaction(trans, root);
740 }
741
742 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
743 struct btrfs_root *root, int throttle)
744 {
745 struct btrfs_transaction *cur_trans = trans->transaction;
746 struct btrfs_fs_info *info = root->fs_info;
747 unsigned long cur = trans->delayed_ref_updates;
748 int lock = (trans->type != TRANS_JOIN_NOLOCK);
749 int err = 0;
750 int must_run_delayed_refs = 0;
751
752 if (trans->use_count > 1) {
753 trans->use_count--;
754 trans->block_rsv = trans->orig_rsv;
755 return 0;
756 }
757
758 btrfs_trans_release_metadata(trans, root);
759 trans->block_rsv = NULL;
760
761 if (!list_empty(&trans->new_bgs))
762 btrfs_create_pending_block_groups(trans, root);
763
764 if (!list_empty(&trans->ordered)) {
765 spin_lock(&info->trans_lock);
766 list_splice_init(&trans->ordered, &cur_trans->pending_ordered);
767 spin_unlock(&info->trans_lock);
768 }
769
770 trans->delayed_ref_updates = 0;
771 if (!trans->sync) {
772 must_run_delayed_refs =
773 btrfs_should_throttle_delayed_refs(trans, root);
774 cur = max_t(unsigned long, cur, 32);
775
776 /*
777 * don't make the caller wait if they are from a NOLOCK
778 * or ATTACH transaction, it will deadlock with commit
779 */
780 if (must_run_delayed_refs == 1 &&
781 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH)))
782 must_run_delayed_refs = 2;
783 }
784
785 if (trans->qgroup_reserved) {
786 /*
787 * the same root has to be passed here between start_transaction
788 * and end_transaction. Subvolume quota depends on this.
789 */
790 btrfs_qgroup_free(trans->root, trans->qgroup_reserved);
791 trans->qgroup_reserved = 0;
792 }
793
794 btrfs_trans_release_metadata(trans, root);
795 trans->block_rsv = NULL;
796
797 if (!list_empty(&trans->new_bgs))
798 btrfs_create_pending_block_groups(trans, root);
799
800 btrfs_trans_release_chunk_metadata(trans);
801
802 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
803 should_end_transaction(trans, root) &&
804 ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
805 spin_lock(&info->trans_lock);
806 if (cur_trans->state == TRANS_STATE_RUNNING)
807 cur_trans->state = TRANS_STATE_BLOCKED;
808 spin_unlock(&info->trans_lock);
809 }
810
811 if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
812 if (throttle)
813 return btrfs_commit_transaction(trans, root);
814 else
815 wake_up_process(info->transaction_kthread);
816 }
817
818 if (trans->type & __TRANS_FREEZABLE)
819 sb_end_intwrite(root->fs_info->sb);
820
821 WARN_ON(cur_trans != info->running_transaction);
822 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
823 atomic_dec(&cur_trans->num_writers);
824 extwriter_counter_dec(cur_trans, trans->type);
825
826 smp_mb();
827 if (waitqueue_active(&cur_trans->writer_wait))
828 wake_up(&cur_trans->writer_wait);
829 btrfs_put_transaction(cur_trans);
830
831 if (current->journal_info == trans)
832 current->journal_info = NULL;
833
834 if (throttle)
835 btrfs_run_delayed_iputs(root);
836
837 if (trans->aborted ||
838 test_bit(BTRFS_FS_STATE_ERROR, &root->fs_info->fs_state)) {
839 wake_up_process(info->transaction_kthread);
840 err = -EIO;
841 }
842 assert_qgroups_uptodate(trans);
843
844 kmem_cache_free(btrfs_trans_handle_cachep, trans);
845 if (must_run_delayed_refs) {
846 btrfs_async_run_delayed_refs(root, cur,
847 must_run_delayed_refs == 1);
848 }
849 return err;
850 }
851
852 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
853 struct btrfs_root *root)
854 {
855 return __btrfs_end_transaction(trans, root, 0);
856 }
857
858 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
859 struct btrfs_root *root)
860 {
861 return __btrfs_end_transaction(trans, root, 1);
862 }
863
864 /*
865 * when btree blocks are allocated, they have some corresponding bits set for
866 * them in one of two extent_io trees. This is used to make sure all of
867 * those extents are sent to disk but does not wait on them
868 */
869 int btrfs_write_marked_extents(struct btrfs_root *root,
870 struct extent_io_tree *dirty_pages, int mark)
871 {
872 int err = 0;
873 int werr = 0;
874 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
875 struct extent_state *cached_state = NULL;
876 u64 start = 0;
877 u64 end;
878
879 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
880 mark, &cached_state)) {
881 bool wait_writeback = false;
882
883 err = convert_extent_bit(dirty_pages, start, end,
884 EXTENT_NEED_WAIT,
885 mark, &cached_state, GFP_NOFS);
886 /*
887 * convert_extent_bit can return -ENOMEM, which is most of the
888 * time a temporary error. So when it happens, ignore the error
889 * and wait for writeback of this range to finish - because we
890 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
891 * to btrfs_wait_marked_extents() would not know that writeback
892 * for this range started and therefore wouldn't wait for it to
893 * finish - we don't want to commit a superblock that points to
894 * btree nodes/leafs for which writeback hasn't finished yet
895 * (and without errors).
896 * We cleanup any entries left in the io tree when committing
897 * the transaction (through clear_btree_io_tree()).
898 */
899 if (err == -ENOMEM) {
900 err = 0;
901 wait_writeback = true;
902 }
903 if (!err)
904 err = filemap_fdatawrite_range(mapping, start, end);
905 if (err)
906 werr = err;
907 else if (wait_writeback)
908 werr = filemap_fdatawait_range(mapping, start, end);
909 free_extent_state(cached_state);
910 cached_state = NULL;
911 cond_resched();
912 start = end + 1;
913 }
914 return werr;
915 }
916
917 /*
918 * when btree blocks are allocated, they have some corresponding bits set for
919 * them in one of two extent_io trees. This is used to make sure all of
920 * those extents are on disk for transaction or log commit. We wait
921 * on all the pages and clear them from the dirty pages state tree
922 */
923 int btrfs_wait_marked_extents(struct btrfs_root *root,
924 struct extent_io_tree *dirty_pages, int mark)
925 {
926 int err = 0;
927 int werr = 0;
928 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
929 struct extent_state *cached_state = NULL;
930 u64 start = 0;
931 u64 end;
932 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode);
933 bool errors = false;
934
935 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
936 EXTENT_NEED_WAIT, &cached_state)) {
937 /*
938 * Ignore -ENOMEM errors returned by clear_extent_bit().
939 * When committing the transaction, we'll remove any entries
940 * left in the io tree. For a log commit, we don't remove them
941 * after committing the log because the tree can be accessed
942 * concurrently - we do it only at transaction commit time when
943 * it's safe to do it (through clear_btree_io_tree()).
944 */
945 err = clear_extent_bit(dirty_pages, start, end,
946 EXTENT_NEED_WAIT,
947 0, 0, &cached_state, GFP_NOFS);
948 if (err == -ENOMEM)
949 err = 0;
950 if (!err)
951 err = filemap_fdatawait_range(mapping, start, end);
952 if (err)
953 werr = err;
954 free_extent_state(cached_state);
955 cached_state = NULL;
956 cond_resched();
957 start = end + 1;
958 }
959 if (err)
960 werr = err;
961
962 if (root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID) {
963 if ((mark & EXTENT_DIRTY) &&
964 test_and_clear_bit(BTRFS_INODE_BTREE_LOG1_ERR,
965 &btree_ino->runtime_flags))
966 errors = true;
967
968 if ((mark & EXTENT_NEW) &&
969 test_and_clear_bit(BTRFS_INODE_BTREE_LOG2_ERR,
970 &btree_ino->runtime_flags))
971 errors = true;
972 } else {
973 if (test_and_clear_bit(BTRFS_INODE_BTREE_ERR,
974 &btree_ino->runtime_flags))
975 errors = true;
976 }
977
978 if (errors && !werr)
979 werr = -EIO;
980
981 return werr;
982 }
983
984 /*
985 * when btree blocks are allocated, they have some corresponding bits set for
986 * them in one of two extent_io trees. This is used to make sure all of
987 * those extents are on disk for transaction or log commit
988 */
989 static int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
990 struct extent_io_tree *dirty_pages, int mark)
991 {
992 int ret;
993 int ret2;
994 struct blk_plug plug;
995
996 blk_start_plug(&plug);
997 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
998 blk_finish_plug(&plug);
999 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
1000
1001 if (ret)
1002 return ret;
1003 if (ret2)
1004 return ret2;
1005 return 0;
1006 }
1007
1008 static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
1009 struct btrfs_root *root)
1010 {
1011 int ret;
1012
1013 ret = btrfs_write_and_wait_marked_extents(root,
1014 &trans->transaction->dirty_pages,
1015 EXTENT_DIRTY);
1016 clear_btree_io_tree(&trans->transaction->dirty_pages);
1017
1018 return ret;
1019 }
1020
1021 /*
1022 * this is used to update the root pointer in the tree of tree roots.
1023 *
1024 * But, in the case of the extent allocation tree, updating the root
1025 * pointer may allocate blocks which may change the root of the extent
1026 * allocation tree.
1027 *
1028 * So, this loops and repeats and makes sure the cowonly root didn't
1029 * change while the root pointer was being updated in the metadata.
1030 */
1031 static int update_cowonly_root(struct btrfs_trans_handle *trans,
1032 struct btrfs_root *root)
1033 {
1034 int ret;
1035 u64 old_root_bytenr;
1036 u64 old_root_used;
1037 struct btrfs_root *tree_root = root->fs_info->tree_root;
1038
1039 old_root_used = btrfs_root_used(&root->root_item);
1040
1041 while (1) {
1042 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1043 if (old_root_bytenr == root->node->start &&
1044 old_root_used == btrfs_root_used(&root->root_item))
1045 break;
1046
1047 btrfs_set_root_node(&root->root_item, root->node);
1048 ret = btrfs_update_root(trans, tree_root,
1049 &root->root_key,
1050 &root->root_item);
1051 if (ret)
1052 return ret;
1053
1054 old_root_used = btrfs_root_used(&root->root_item);
1055 }
1056
1057 return 0;
1058 }
1059
1060 /*
1061 * update all the cowonly tree roots on disk
1062 *
1063 * The error handling in this function may not be obvious. Any of the
1064 * failures will cause the file system to go offline. We still need
1065 * to clean up the delayed refs.
1066 */
1067 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
1068 struct btrfs_root *root)
1069 {
1070 struct btrfs_fs_info *fs_info = root->fs_info;
1071 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1072 struct list_head *io_bgs = &trans->transaction->io_bgs;
1073 struct list_head *next;
1074 struct extent_buffer *eb;
1075 int ret;
1076
1077 eb = btrfs_lock_root_node(fs_info->tree_root);
1078 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1079 0, &eb);
1080 btrfs_tree_unlock(eb);
1081 free_extent_buffer(eb);
1082
1083 if (ret)
1084 return ret;
1085
1086 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1087 if (ret)
1088 return ret;
1089
1090 ret = btrfs_run_dev_stats(trans, root->fs_info);
1091 if (ret)
1092 return ret;
1093 ret = btrfs_run_dev_replace(trans, root->fs_info);
1094 if (ret)
1095 return ret;
1096 ret = btrfs_run_qgroups(trans, root->fs_info);
1097 if (ret)
1098 return ret;
1099
1100 ret = btrfs_setup_space_cache(trans, root);
1101 if (ret)
1102 return ret;
1103
1104 /* run_qgroups might have added some more refs */
1105 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1106 if (ret)
1107 return ret;
1108 again:
1109 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1110 next = fs_info->dirty_cowonly_roots.next;
1111 list_del_init(next);
1112 root = list_entry(next, struct btrfs_root, dirty_list);
1113 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1114
1115 if (root != fs_info->extent_root)
1116 list_add_tail(&root->dirty_list,
1117 &trans->transaction->switch_commits);
1118 ret = update_cowonly_root(trans, root);
1119 if (ret)
1120 return ret;
1121 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1122 if (ret)
1123 return ret;
1124 }
1125
1126 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1127 ret = btrfs_write_dirty_block_groups(trans, root);
1128 if (ret)
1129 return ret;
1130 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1131 if (ret)
1132 return ret;
1133 }
1134
1135 if (!list_empty(&fs_info->dirty_cowonly_roots))
1136 goto again;
1137
1138 list_add_tail(&fs_info->extent_root->dirty_list,
1139 &trans->transaction->switch_commits);
1140 btrfs_after_dev_replace_commit(fs_info);
1141
1142 return 0;
1143 }
1144
1145 /*
1146 * dead roots are old snapshots that need to be deleted. This allocates
1147 * a dirty root struct and adds it into the list of dead roots that need to
1148 * be deleted
1149 */
1150 void btrfs_add_dead_root(struct btrfs_root *root)
1151 {
1152 spin_lock(&root->fs_info->trans_lock);
1153 if (list_empty(&root->root_list))
1154 list_add_tail(&root->root_list, &root->fs_info->dead_roots);
1155 spin_unlock(&root->fs_info->trans_lock);
1156 }
1157
1158 /*
1159 * update all the cowonly tree roots on disk
1160 */
1161 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
1162 struct btrfs_root *root)
1163 {
1164 struct btrfs_root *gang[8];
1165 struct btrfs_fs_info *fs_info = root->fs_info;
1166 int i;
1167 int ret;
1168 int err = 0;
1169
1170 spin_lock(&fs_info->fs_roots_radix_lock);
1171 while (1) {
1172 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1173 (void **)gang, 0,
1174 ARRAY_SIZE(gang),
1175 BTRFS_ROOT_TRANS_TAG);
1176 if (ret == 0)
1177 break;
1178 for (i = 0; i < ret; i++) {
1179 root = gang[i];
1180 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1181 (unsigned long)root->root_key.objectid,
1182 BTRFS_ROOT_TRANS_TAG);
1183 spin_unlock(&fs_info->fs_roots_radix_lock);
1184
1185 btrfs_free_log(trans, root);
1186 btrfs_update_reloc_root(trans, root);
1187 btrfs_orphan_commit_root(trans, root);
1188
1189 btrfs_save_ino_cache(root, trans);
1190
1191 /* see comments in should_cow_block() */
1192 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1193 smp_mb__after_atomic();
1194
1195 if (root->commit_root != root->node) {
1196 list_add_tail(&root->dirty_list,
1197 &trans->transaction->switch_commits);
1198 btrfs_set_root_node(&root->root_item,
1199 root->node);
1200 }
1201
1202 err = btrfs_update_root(trans, fs_info->tree_root,
1203 &root->root_key,
1204 &root->root_item);
1205 spin_lock(&fs_info->fs_roots_radix_lock);
1206 if (err)
1207 break;
1208 }
1209 }
1210 spin_unlock(&fs_info->fs_roots_radix_lock);
1211 return err;
1212 }
1213
1214 /*
1215 * defrag a given btree.
1216 * Every leaf in the btree is read and defragged.
1217 */
1218 int btrfs_defrag_root(struct btrfs_root *root)
1219 {
1220 struct btrfs_fs_info *info = root->fs_info;
1221 struct btrfs_trans_handle *trans;
1222 int ret;
1223
1224 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1225 return 0;
1226
1227 while (1) {
1228 trans = btrfs_start_transaction(root, 0);
1229 if (IS_ERR(trans))
1230 return PTR_ERR(trans);
1231
1232 ret = btrfs_defrag_leaves(trans, root);
1233
1234 btrfs_end_transaction(trans, root);
1235 btrfs_btree_balance_dirty(info->tree_root);
1236 cond_resched();
1237
1238 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
1239 break;
1240
1241 if (btrfs_defrag_cancelled(root->fs_info)) {
1242 pr_debug("BTRFS: defrag_root cancelled\n");
1243 ret = -EAGAIN;
1244 break;
1245 }
1246 }
1247 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1248 return ret;
1249 }
1250
1251 /*
1252 * new snapshots need to be created at a very specific time in the
1253 * transaction commit. This does the actual creation.
1254 *
1255 * Note:
1256 * If the error which may affect the commitment of the current transaction
1257 * happens, we should return the error number. If the error which just affect
1258 * the creation of the pending snapshots, just return 0.
1259 */
1260 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1261 struct btrfs_fs_info *fs_info,
1262 struct btrfs_pending_snapshot *pending)
1263 {
1264 struct btrfs_key key;
1265 struct btrfs_root_item *new_root_item;
1266 struct btrfs_root *tree_root = fs_info->tree_root;
1267 struct btrfs_root *root = pending->root;
1268 struct btrfs_root *parent_root;
1269 struct btrfs_block_rsv *rsv;
1270 struct inode *parent_inode;
1271 struct btrfs_path *path;
1272 struct btrfs_dir_item *dir_item;
1273 struct dentry *dentry;
1274 struct extent_buffer *tmp;
1275 struct extent_buffer *old;
1276 struct timespec cur_time = CURRENT_TIME;
1277 int ret = 0;
1278 u64 to_reserve = 0;
1279 u64 index = 0;
1280 u64 objectid;
1281 u64 root_flags;
1282 uuid_le new_uuid;
1283
1284 path = btrfs_alloc_path();
1285 if (!path) {
1286 pending->error = -ENOMEM;
1287 return 0;
1288 }
1289
1290 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
1291 if (!new_root_item) {
1292 pending->error = -ENOMEM;
1293 goto root_item_alloc_fail;
1294 }
1295
1296 pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1297 if (pending->error)
1298 goto no_free_objectid;
1299
1300 /*
1301 * Make qgroup to skip current new snapshot's qgroupid, as it is
1302 * accounted by later btrfs_qgroup_inherit().
1303 */
1304 btrfs_set_skip_qgroup(trans, objectid);
1305
1306 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1307
1308 if (to_reserve > 0) {
1309 pending->error = btrfs_block_rsv_add(root,
1310 &pending->block_rsv,
1311 to_reserve,
1312 BTRFS_RESERVE_NO_FLUSH);
1313 if (pending->error)
1314 goto clear_skip_qgroup;
1315 }
1316
1317 key.objectid = objectid;
1318 key.offset = (u64)-1;
1319 key.type = BTRFS_ROOT_ITEM_KEY;
1320
1321 rsv = trans->block_rsv;
1322 trans->block_rsv = &pending->block_rsv;
1323 trans->bytes_reserved = trans->block_rsv->reserved;
1324
1325 dentry = pending->dentry;
1326 parent_inode = pending->dir;
1327 parent_root = BTRFS_I(parent_inode)->root;
1328 record_root_in_trans(trans, parent_root);
1329
1330 /*
1331 * insert the directory item
1332 */
1333 ret = btrfs_set_inode_index(parent_inode, &index);
1334 BUG_ON(ret); /* -ENOMEM */
1335
1336 /* check if there is a file/dir which has the same name. */
1337 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1338 btrfs_ino(parent_inode),
1339 dentry->d_name.name,
1340 dentry->d_name.len, 0);
1341 if (dir_item != NULL && !IS_ERR(dir_item)) {
1342 pending->error = -EEXIST;
1343 goto dir_item_existed;
1344 } else if (IS_ERR(dir_item)) {
1345 ret = PTR_ERR(dir_item);
1346 btrfs_abort_transaction(trans, root, ret);
1347 goto fail;
1348 }
1349 btrfs_release_path(path);
1350
1351 /*
1352 * pull in the delayed directory update
1353 * and the delayed inode item
1354 * otherwise we corrupt the FS during
1355 * snapshot
1356 */
1357 ret = btrfs_run_delayed_items(trans, root);
1358 if (ret) { /* Transaction aborted */
1359 btrfs_abort_transaction(trans, root, ret);
1360 goto fail;
1361 }
1362
1363 record_root_in_trans(trans, root);
1364 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1365 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1366 btrfs_check_and_init_root_item(new_root_item);
1367
1368 root_flags = btrfs_root_flags(new_root_item);
1369 if (pending->readonly)
1370 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1371 else
1372 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1373 btrfs_set_root_flags(new_root_item, root_flags);
1374
1375 btrfs_set_root_generation_v2(new_root_item,
1376 trans->transid);
1377 uuid_le_gen(&new_uuid);
1378 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1379 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1380 BTRFS_UUID_SIZE);
1381 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1382 memset(new_root_item->received_uuid, 0,
1383 sizeof(new_root_item->received_uuid));
1384 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1385 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1386 btrfs_set_root_stransid(new_root_item, 0);
1387 btrfs_set_root_rtransid(new_root_item, 0);
1388 }
1389 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1390 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1391 btrfs_set_root_otransid(new_root_item, trans->transid);
1392
1393 old = btrfs_lock_root_node(root);
1394 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1395 if (ret) {
1396 btrfs_tree_unlock(old);
1397 free_extent_buffer(old);
1398 btrfs_abort_transaction(trans, root, ret);
1399 goto fail;
1400 }
1401
1402 btrfs_set_lock_blocking(old);
1403
1404 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1405 /* clean up in any case */
1406 btrfs_tree_unlock(old);
1407 free_extent_buffer(old);
1408 if (ret) {
1409 btrfs_abort_transaction(trans, root, ret);
1410 goto fail;
1411 }
1412 /* see comments in should_cow_block() */
1413 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1414 smp_wmb();
1415
1416 btrfs_set_root_node(new_root_item, tmp);
1417 /* record when the snapshot was created in key.offset */
1418 key.offset = trans->transid;
1419 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1420 btrfs_tree_unlock(tmp);
1421 free_extent_buffer(tmp);
1422 if (ret) {
1423 btrfs_abort_transaction(trans, root, ret);
1424 goto fail;
1425 }
1426
1427 /*
1428 * insert root back/forward references
1429 */
1430 ret = btrfs_add_root_ref(trans, tree_root, objectid,
1431 parent_root->root_key.objectid,
1432 btrfs_ino(parent_inode), index,
1433 dentry->d_name.name, dentry->d_name.len);
1434 if (ret) {
1435 btrfs_abort_transaction(trans, root, ret);
1436 goto fail;
1437 }
1438
1439 key.offset = (u64)-1;
1440 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1441 if (IS_ERR(pending->snap)) {
1442 ret = PTR_ERR(pending->snap);
1443 btrfs_abort_transaction(trans, root, ret);
1444 goto fail;
1445 }
1446
1447 ret = btrfs_reloc_post_snapshot(trans, pending);
1448 if (ret) {
1449 btrfs_abort_transaction(trans, root, ret);
1450 goto fail;
1451 }
1452
1453 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1454 if (ret) {
1455 btrfs_abort_transaction(trans, root, ret);
1456 goto fail;
1457 }
1458
1459 ret = btrfs_insert_dir_item(trans, parent_root,
1460 dentry->d_name.name, dentry->d_name.len,
1461 parent_inode, &key,
1462 BTRFS_FT_DIR, index);
1463 /* We have check then name at the beginning, so it is impossible. */
1464 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1465 if (ret) {
1466 btrfs_abort_transaction(trans, root, ret);
1467 goto fail;
1468 }
1469
1470 btrfs_i_size_write(parent_inode, parent_inode->i_size +
1471 dentry->d_name.len * 2);
1472 parent_inode->i_mtime = parent_inode->i_ctime = CURRENT_TIME;
1473 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1474 if (ret) {
1475 btrfs_abort_transaction(trans, root, ret);
1476 goto fail;
1477 }
1478 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root, new_uuid.b,
1479 BTRFS_UUID_KEY_SUBVOL, objectid);
1480 if (ret) {
1481 btrfs_abort_transaction(trans, root, ret);
1482 goto fail;
1483 }
1484 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1485 ret = btrfs_uuid_tree_add(trans, fs_info->uuid_root,
1486 new_root_item->received_uuid,
1487 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1488 objectid);
1489 if (ret && ret != -EEXIST) {
1490 btrfs_abort_transaction(trans, root, ret);
1491 goto fail;
1492 }
1493 }
1494
1495 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1496 if (ret) {
1497 btrfs_abort_transaction(trans, root, ret);
1498 goto fail;
1499 }
1500
1501 /*
1502 * account qgroup counters before qgroup_inherit()
1503 */
1504 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info);
1505 if (ret)
1506 goto fail;
1507 ret = btrfs_qgroup_account_extents(trans, fs_info);
1508 if (ret)
1509 goto fail;
1510 ret = btrfs_qgroup_inherit(trans, fs_info,
1511 root->root_key.objectid,
1512 objectid, pending->inherit);
1513 if (ret) {
1514 btrfs_abort_transaction(trans, root, ret);
1515 goto fail;
1516 }
1517
1518 fail:
1519 pending->error = ret;
1520 dir_item_existed:
1521 trans->block_rsv = rsv;
1522 trans->bytes_reserved = 0;
1523 clear_skip_qgroup:
1524 btrfs_clear_skip_qgroup(trans);
1525 no_free_objectid:
1526 kfree(new_root_item);
1527 root_item_alloc_fail:
1528 btrfs_free_path(path);
1529 return ret;
1530 }
1531
1532 /*
1533 * create all the snapshots we've scheduled for creation
1534 */
1535 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1536 struct btrfs_fs_info *fs_info)
1537 {
1538 struct btrfs_pending_snapshot *pending, *next;
1539 struct list_head *head = &trans->transaction->pending_snapshots;
1540 int ret = 0;
1541
1542 list_for_each_entry_safe(pending, next, head, list) {
1543 list_del(&pending->list);
1544 ret = create_pending_snapshot(trans, fs_info, pending);
1545 if (ret)
1546 break;
1547 }
1548 return ret;
1549 }
1550
1551 static void update_super_roots(struct btrfs_root *root)
1552 {
1553 struct btrfs_root_item *root_item;
1554 struct btrfs_super_block *super;
1555
1556 super = root->fs_info->super_copy;
1557
1558 root_item = &root->fs_info->chunk_root->root_item;
1559 super->chunk_root = root_item->bytenr;
1560 super->chunk_root_generation = root_item->generation;
1561 super->chunk_root_level = root_item->level;
1562
1563 root_item = &root->fs_info->tree_root->root_item;
1564 super->root = root_item->bytenr;
1565 super->generation = root_item->generation;
1566 super->root_level = root_item->level;
1567 if (btrfs_test_opt(root, SPACE_CACHE))
1568 super->cache_generation = root_item->generation;
1569 if (root->fs_info->update_uuid_tree_gen)
1570 super->uuid_tree_generation = root_item->generation;
1571 }
1572
1573 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1574 {
1575 struct btrfs_transaction *trans;
1576 int ret = 0;
1577
1578 spin_lock(&info->trans_lock);
1579 trans = info->running_transaction;
1580 if (trans)
1581 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1582 spin_unlock(&info->trans_lock);
1583 return ret;
1584 }
1585
1586 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1587 {
1588 struct btrfs_transaction *trans;
1589 int ret = 0;
1590
1591 spin_lock(&info->trans_lock);
1592 trans = info->running_transaction;
1593 if (trans)
1594 ret = is_transaction_blocked(trans);
1595 spin_unlock(&info->trans_lock);
1596 return ret;
1597 }
1598
1599 /*
1600 * wait for the current transaction commit to start and block subsequent
1601 * transaction joins
1602 */
1603 static void wait_current_trans_commit_start(struct btrfs_root *root,
1604 struct btrfs_transaction *trans)
1605 {
1606 wait_event(root->fs_info->transaction_blocked_wait,
1607 trans->state >= TRANS_STATE_COMMIT_START ||
1608 trans->aborted);
1609 }
1610
1611 /*
1612 * wait for the current transaction to start and then become unblocked.
1613 * caller holds ref.
1614 */
1615 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1616 struct btrfs_transaction *trans)
1617 {
1618 wait_event(root->fs_info->transaction_wait,
1619 trans->state >= TRANS_STATE_UNBLOCKED ||
1620 trans->aborted);
1621 }
1622
1623 /*
1624 * commit transactions asynchronously. once btrfs_commit_transaction_async
1625 * returns, any subsequent transaction will not be allowed to join.
1626 */
1627 struct btrfs_async_commit {
1628 struct btrfs_trans_handle *newtrans;
1629 struct btrfs_root *root;
1630 struct work_struct work;
1631 };
1632
1633 static void do_async_commit(struct work_struct *work)
1634 {
1635 struct btrfs_async_commit *ac =
1636 container_of(work, struct btrfs_async_commit, work);
1637
1638 /*
1639 * We've got freeze protection passed with the transaction.
1640 * Tell lockdep about it.
1641 */
1642 if (ac->newtrans->type & __TRANS_FREEZABLE)
1643 rwsem_acquire_read(
1644 &ac->root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
1645 0, 1, _THIS_IP_);
1646
1647 current->journal_info = ac->newtrans;
1648
1649 btrfs_commit_transaction(ac->newtrans, ac->root);
1650 kfree(ac);
1651 }
1652
1653 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1654 struct btrfs_root *root,
1655 int wait_for_unblock)
1656 {
1657 struct btrfs_async_commit *ac;
1658 struct btrfs_transaction *cur_trans;
1659
1660 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1661 if (!ac)
1662 return -ENOMEM;
1663
1664 INIT_WORK(&ac->work, do_async_commit);
1665 ac->root = root;
1666 ac->newtrans = btrfs_join_transaction(root);
1667 if (IS_ERR(ac->newtrans)) {
1668 int err = PTR_ERR(ac->newtrans);
1669 kfree(ac);
1670 return err;
1671 }
1672
1673 /* take transaction reference */
1674 cur_trans = trans->transaction;
1675 atomic_inc(&cur_trans->use_count);
1676
1677 btrfs_end_transaction(trans, root);
1678
1679 /*
1680 * Tell lockdep we've released the freeze rwsem, since the
1681 * async commit thread will be the one to unlock it.
1682 */
1683 if (ac->newtrans->type & __TRANS_FREEZABLE)
1684 rwsem_release(
1685 &root->fs_info->sb->s_writers.lock_map[SB_FREEZE_FS-1],
1686 1, _THIS_IP_);
1687
1688 schedule_work(&ac->work);
1689
1690 /* wait for transaction to start and unblock */
1691 if (wait_for_unblock)
1692 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1693 else
1694 wait_current_trans_commit_start(root, cur_trans);
1695
1696 if (current->journal_info == trans)
1697 current->journal_info = NULL;
1698
1699 btrfs_put_transaction(cur_trans);
1700 return 0;
1701 }
1702
1703
1704 static void cleanup_transaction(struct btrfs_trans_handle *trans,
1705 struct btrfs_root *root, int err)
1706 {
1707 struct btrfs_transaction *cur_trans = trans->transaction;
1708 DEFINE_WAIT(wait);
1709
1710 WARN_ON(trans->use_count > 1);
1711
1712 btrfs_abort_transaction(trans, root, err);
1713
1714 spin_lock(&root->fs_info->trans_lock);
1715
1716 /*
1717 * If the transaction is removed from the list, it means this
1718 * transaction has been committed successfully, so it is impossible
1719 * to call the cleanup function.
1720 */
1721 BUG_ON(list_empty(&cur_trans->list));
1722
1723 list_del_init(&cur_trans->list);
1724 if (cur_trans == root->fs_info->running_transaction) {
1725 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1726 spin_unlock(&root->fs_info->trans_lock);
1727 wait_event(cur_trans->writer_wait,
1728 atomic_read(&cur_trans->num_writers) == 1);
1729
1730 spin_lock(&root->fs_info->trans_lock);
1731 }
1732 spin_unlock(&root->fs_info->trans_lock);
1733
1734 btrfs_cleanup_one_transaction(trans->transaction, root);
1735
1736 spin_lock(&root->fs_info->trans_lock);
1737 if (cur_trans == root->fs_info->running_transaction)
1738 root->fs_info->running_transaction = NULL;
1739 spin_unlock(&root->fs_info->trans_lock);
1740
1741 if (trans->type & __TRANS_FREEZABLE)
1742 sb_end_intwrite(root->fs_info->sb);
1743 btrfs_put_transaction(cur_trans);
1744 btrfs_put_transaction(cur_trans);
1745
1746 trace_btrfs_transaction_commit(root);
1747
1748 if (current->journal_info == trans)
1749 current->journal_info = NULL;
1750 btrfs_scrub_cancel(root->fs_info);
1751
1752 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1753 }
1754
1755 static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1756 {
1757 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1758 return btrfs_start_delalloc_roots(fs_info, 1, -1);
1759 return 0;
1760 }
1761
1762 static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1763 {
1764 if (btrfs_test_opt(fs_info->tree_root, FLUSHONCOMMIT))
1765 btrfs_wait_ordered_roots(fs_info, -1);
1766 }
1767
1768 static inline void
1769 btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans,
1770 struct btrfs_fs_info *fs_info)
1771 {
1772 struct btrfs_ordered_extent *ordered;
1773
1774 spin_lock(&fs_info->trans_lock);
1775 while (!list_empty(&cur_trans->pending_ordered)) {
1776 ordered = list_first_entry(&cur_trans->pending_ordered,
1777 struct btrfs_ordered_extent,
1778 trans_list);
1779 list_del_init(&ordered->trans_list);
1780 spin_unlock(&fs_info->trans_lock);
1781
1782 wait_event(ordered->wait, test_bit(BTRFS_ORDERED_COMPLETE,
1783 &ordered->flags));
1784 btrfs_put_ordered_extent(ordered);
1785 spin_lock(&fs_info->trans_lock);
1786 }
1787 spin_unlock(&fs_info->trans_lock);
1788 }
1789
1790 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1791 struct btrfs_root *root)
1792 {
1793 struct btrfs_transaction *cur_trans = trans->transaction;
1794 struct btrfs_transaction *prev_trans = NULL;
1795 struct btrfs_inode *btree_ino = BTRFS_I(root->fs_info->btree_inode);
1796 int ret;
1797
1798 /* Stop the commit early if ->aborted is set */
1799 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1800 ret = cur_trans->aborted;
1801 btrfs_end_transaction(trans, root);
1802 return ret;
1803 }
1804
1805 /* make a pass through all the delayed refs we have so far
1806 * any runnings procs may add more while we are here
1807 */
1808 ret = btrfs_run_delayed_refs(trans, root, 0);
1809 if (ret) {
1810 btrfs_end_transaction(trans, root);
1811 return ret;
1812 }
1813
1814 btrfs_trans_release_metadata(trans, root);
1815 trans->block_rsv = NULL;
1816 if (trans->qgroup_reserved) {
1817 btrfs_qgroup_free(root, trans->qgroup_reserved);
1818 trans->qgroup_reserved = 0;
1819 }
1820
1821 cur_trans = trans->transaction;
1822
1823 /*
1824 * set the flushing flag so procs in this transaction have to
1825 * start sending their work down.
1826 */
1827 cur_trans->delayed_refs.flushing = 1;
1828 smp_wmb();
1829
1830 if (!list_empty(&trans->new_bgs))
1831 btrfs_create_pending_block_groups(trans, root);
1832
1833 ret = btrfs_run_delayed_refs(trans, root, 0);
1834 if (ret) {
1835 btrfs_end_transaction(trans, root);
1836 return ret;
1837 }
1838
1839 if (!cur_trans->dirty_bg_run) {
1840 int run_it = 0;
1841
1842 /* this mutex is also taken before trying to set
1843 * block groups readonly. We need to make sure
1844 * that nobody has set a block group readonly
1845 * after a extents from that block group have been
1846 * allocated for cache files. btrfs_set_block_group_ro
1847 * will wait for the transaction to commit if it
1848 * finds dirty_bg_run = 1
1849 *
1850 * The dirty_bg_run flag is also used to make sure only
1851 * one process starts all the block group IO. It wouldn't
1852 * hurt to have more than one go through, but there's no
1853 * real advantage to it either.
1854 */
1855 mutex_lock(&root->fs_info->ro_block_group_mutex);
1856 if (!cur_trans->dirty_bg_run) {
1857 run_it = 1;
1858 cur_trans->dirty_bg_run = 1;
1859 }
1860 mutex_unlock(&root->fs_info->ro_block_group_mutex);
1861
1862 if (run_it)
1863 ret = btrfs_start_dirty_block_groups(trans, root);
1864 }
1865 if (ret) {
1866 btrfs_end_transaction(trans, root);
1867 return ret;
1868 }
1869
1870 spin_lock(&root->fs_info->trans_lock);
1871 list_splice_init(&trans->ordered, &cur_trans->pending_ordered);
1872 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
1873 spin_unlock(&root->fs_info->trans_lock);
1874 atomic_inc(&cur_trans->use_count);
1875 ret = btrfs_end_transaction(trans, root);
1876
1877 wait_for_commit(root, cur_trans);
1878
1879 if (unlikely(cur_trans->aborted))
1880 ret = cur_trans->aborted;
1881
1882 btrfs_put_transaction(cur_trans);
1883
1884 return ret;
1885 }
1886
1887 cur_trans->state = TRANS_STATE_COMMIT_START;
1888 wake_up(&root->fs_info->transaction_blocked_wait);
1889
1890 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1891 prev_trans = list_entry(cur_trans->list.prev,
1892 struct btrfs_transaction, list);
1893 if (prev_trans->state != TRANS_STATE_COMPLETED) {
1894 atomic_inc(&prev_trans->use_count);
1895 spin_unlock(&root->fs_info->trans_lock);
1896
1897 wait_for_commit(root, prev_trans);
1898
1899 btrfs_put_transaction(prev_trans);
1900 } else {
1901 spin_unlock(&root->fs_info->trans_lock);
1902 }
1903 } else {
1904 spin_unlock(&root->fs_info->trans_lock);
1905 }
1906
1907 extwriter_counter_dec(cur_trans, trans->type);
1908
1909 ret = btrfs_start_delalloc_flush(root->fs_info);
1910 if (ret)
1911 goto cleanup_transaction;
1912
1913 ret = btrfs_run_delayed_items(trans, root);
1914 if (ret)
1915 goto cleanup_transaction;
1916
1917 wait_event(cur_trans->writer_wait,
1918 extwriter_counter_read(cur_trans) == 0);
1919
1920 /* some pending stuffs might be added after the previous flush. */
1921 ret = btrfs_run_delayed_items(trans, root);
1922 if (ret)
1923 goto cleanup_transaction;
1924
1925 btrfs_wait_delalloc_flush(root->fs_info);
1926
1927 btrfs_wait_pending_ordered(cur_trans, root->fs_info);
1928
1929 btrfs_scrub_pause(root);
1930 /*
1931 * Ok now we need to make sure to block out any other joins while we
1932 * commit the transaction. We could have started a join before setting
1933 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
1934 */
1935 spin_lock(&root->fs_info->trans_lock);
1936 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1937 spin_unlock(&root->fs_info->trans_lock);
1938 wait_event(cur_trans->writer_wait,
1939 atomic_read(&cur_trans->num_writers) == 1);
1940
1941 /* ->aborted might be set after the previous check, so check it */
1942 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1943 ret = cur_trans->aborted;
1944 goto scrub_continue;
1945 }
1946 /*
1947 * the reloc mutex makes sure that we stop
1948 * the balancing code from coming in and moving
1949 * extents around in the middle of the commit
1950 */
1951 mutex_lock(&root->fs_info->reloc_mutex);
1952
1953 /*
1954 * We needn't worry about the delayed items because we will
1955 * deal with them in create_pending_snapshot(), which is the
1956 * core function of the snapshot creation.
1957 */
1958 ret = create_pending_snapshots(trans, root->fs_info);
1959 if (ret) {
1960 mutex_unlock(&root->fs_info->reloc_mutex);
1961 goto scrub_continue;
1962 }
1963
1964 /*
1965 * We insert the dir indexes of the snapshots and update the inode
1966 * of the snapshots' parents after the snapshot creation, so there
1967 * are some delayed items which are not dealt with. Now deal with
1968 * them.
1969 *
1970 * We needn't worry that this operation will corrupt the snapshots,
1971 * because all the tree which are snapshoted will be forced to COW
1972 * the nodes and leaves.
1973 */
1974 ret = btrfs_run_delayed_items(trans, root);
1975 if (ret) {
1976 mutex_unlock(&root->fs_info->reloc_mutex);
1977 goto scrub_continue;
1978 }
1979
1980 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1981 if (ret) {
1982 mutex_unlock(&root->fs_info->reloc_mutex);
1983 goto scrub_continue;
1984 }
1985
1986 /* Reocrd old roots for later qgroup accounting */
1987 ret = btrfs_qgroup_prepare_account_extents(trans, root->fs_info);
1988 if (ret) {
1989 mutex_unlock(&root->fs_info->reloc_mutex);
1990 goto scrub_continue;
1991 }
1992
1993 /*
1994 * make sure none of the code above managed to slip in a
1995 * delayed item
1996 */
1997 btrfs_assert_delayed_root_empty(root);
1998
1999 WARN_ON(cur_trans != trans->transaction);
2000
2001 /* btrfs_commit_tree_roots is responsible for getting the
2002 * various roots consistent with each other. Every pointer
2003 * in the tree of tree roots has to point to the most up to date
2004 * root for every subvolume and other tree. So, we have to keep
2005 * the tree logging code from jumping in and changing any
2006 * of the trees.
2007 *
2008 * At this point in the commit, there can't be any tree-log
2009 * writers, but a little lower down we drop the trans mutex
2010 * and let new people in. By holding the tree_log_mutex
2011 * from now until after the super is written, we avoid races
2012 * with the tree-log code.
2013 */
2014 mutex_lock(&root->fs_info->tree_log_mutex);
2015
2016 ret = commit_fs_roots(trans, root);
2017 if (ret) {
2018 mutex_unlock(&root->fs_info->tree_log_mutex);
2019 mutex_unlock(&root->fs_info->reloc_mutex);
2020 goto scrub_continue;
2021 }
2022
2023 /*
2024 * Since the transaction is done, we can apply the pending changes
2025 * before the next transaction.
2026 */
2027 btrfs_apply_pending_changes(root->fs_info);
2028
2029 /* commit_fs_roots gets rid of all the tree log roots, it is now
2030 * safe to free the root of tree log roots
2031 */
2032 btrfs_free_log_root_tree(trans, root->fs_info);
2033
2034 /*
2035 * Since fs roots are all committed, we can get a quite accurate
2036 * new_roots. So let's do quota accounting.
2037 */
2038 ret = btrfs_qgroup_account_extents(trans, root->fs_info);
2039 if (ret < 0) {
2040 mutex_unlock(&root->fs_info->tree_log_mutex);
2041 mutex_unlock(&root->fs_info->reloc_mutex);
2042 goto scrub_continue;
2043 }
2044
2045 ret = commit_cowonly_roots(trans, root);
2046 if (ret) {
2047 mutex_unlock(&root->fs_info->tree_log_mutex);
2048 mutex_unlock(&root->fs_info->reloc_mutex);
2049 goto scrub_continue;
2050 }
2051
2052 /*
2053 * The tasks which save the space cache and inode cache may also
2054 * update ->aborted, check it.
2055 */
2056 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
2057 ret = cur_trans->aborted;
2058 mutex_unlock(&root->fs_info->tree_log_mutex);
2059 mutex_unlock(&root->fs_info->reloc_mutex);
2060 goto scrub_continue;
2061 }
2062
2063 btrfs_prepare_extent_commit(trans, root);
2064
2065 cur_trans = root->fs_info->running_transaction;
2066
2067 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
2068 root->fs_info->tree_root->node);
2069 list_add_tail(&root->fs_info->tree_root->dirty_list,
2070 &cur_trans->switch_commits);
2071
2072 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
2073 root->fs_info->chunk_root->node);
2074 list_add_tail(&root->fs_info->chunk_root->dirty_list,
2075 &cur_trans->switch_commits);
2076
2077 switch_commit_roots(cur_trans, root->fs_info);
2078
2079 assert_qgroups_uptodate(trans);
2080 ASSERT(list_empty(&cur_trans->dirty_bgs));
2081 ASSERT(list_empty(&cur_trans->io_bgs));
2082 update_super_roots(root);
2083
2084 btrfs_set_super_log_root(root->fs_info->super_copy, 0);
2085 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
2086 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
2087 sizeof(*root->fs_info->super_copy));
2088
2089 btrfs_update_commit_device_size(root->fs_info);
2090 btrfs_update_commit_device_bytes_used(root, cur_trans);
2091
2092 clear_bit(BTRFS_INODE_BTREE_LOG1_ERR, &btree_ino->runtime_flags);
2093 clear_bit(BTRFS_INODE_BTREE_LOG2_ERR, &btree_ino->runtime_flags);
2094
2095 btrfs_trans_release_chunk_metadata(trans);
2096
2097 spin_lock(&root->fs_info->trans_lock);
2098 cur_trans->state = TRANS_STATE_UNBLOCKED;
2099 root->fs_info->running_transaction = NULL;
2100 spin_unlock(&root->fs_info->trans_lock);
2101 mutex_unlock(&root->fs_info->reloc_mutex);
2102
2103 wake_up(&root->fs_info->transaction_wait);
2104
2105 ret = btrfs_write_and_wait_transaction(trans, root);
2106 if (ret) {
2107 btrfs_error(root->fs_info, ret,
2108 "Error while writing out transaction");
2109 mutex_unlock(&root->fs_info->tree_log_mutex);
2110 goto scrub_continue;
2111 }
2112
2113 ret = write_ctree_super(trans, root, 0);
2114 if (ret) {
2115 mutex_unlock(&root->fs_info->tree_log_mutex);
2116 goto scrub_continue;
2117 }
2118
2119 /*
2120 * the super is written, we can safely allow the tree-loggers
2121 * to go about their business
2122 */
2123 mutex_unlock(&root->fs_info->tree_log_mutex);
2124
2125 btrfs_finish_extent_commit(trans, root);
2126
2127 if (cur_trans->have_free_bgs)
2128 btrfs_clear_space_info_full(root->fs_info);
2129
2130 root->fs_info->last_trans_committed = cur_trans->transid;
2131 /*
2132 * We needn't acquire the lock here because there is no other task
2133 * which can change it.
2134 */
2135 cur_trans->state = TRANS_STATE_COMPLETED;
2136 wake_up(&cur_trans->commit_wait);
2137
2138 spin_lock(&root->fs_info->trans_lock);
2139 list_del_init(&cur_trans->list);
2140 spin_unlock(&root->fs_info->trans_lock);
2141
2142 btrfs_put_transaction(cur_trans);
2143 btrfs_put_transaction(cur_trans);
2144
2145 if (trans->type & __TRANS_FREEZABLE)
2146 sb_end_intwrite(root->fs_info->sb);
2147
2148 trace_btrfs_transaction_commit(root);
2149
2150 btrfs_scrub_continue(root);
2151
2152 if (current->journal_info == trans)
2153 current->journal_info = NULL;
2154
2155 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2156
2157 if (current != root->fs_info->transaction_kthread &&
2158 current != root->fs_info->cleaner_kthread)
2159 btrfs_run_delayed_iputs(root);
2160
2161 return ret;
2162
2163 scrub_continue:
2164 btrfs_scrub_continue(root);
2165 cleanup_transaction:
2166 btrfs_trans_release_metadata(trans, root);
2167 btrfs_trans_release_chunk_metadata(trans);
2168 trans->block_rsv = NULL;
2169 if (trans->qgroup_reserved) {
2170 btrfs_qgroup_free(root, trans->qgroup_reserved);
2171 trans->qgroup_reserved = 0;
2172 }
2173 btrfs_warn(root->fs_info, "Skipping commit of aborted transaction.");
2174 if (current->journal_info == trans)
2175 current->journal_info = NULL;
2176 cleanup_transaction(trans, root, ret);
2177
2178 return ret;
2179 }
2180
2181 /*
2182 * return < 0 if error
2183 * 0 if there are no more dead_roots at the time of call
2184 * 1 there are more to be processed, call me again
2185 *
2186 * The return value indicates there are certainly more snapshots to delete, but
2187 * if there comes a new one during processing, it may return 0. We don't mind,
2188 * because btrfs_commit_super will poke cleaner thread and it will process it a
2189 * few seconds later.
2190 */
2191 int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2192 {
2193 int ret;
2194 struct btrfs_fs_info *fs_info = root->fs_info;
2195
2196 spin_lock(&fs_info->trans_lock);
2197 if (list_empty(&fs_info->dead_roots)) {
2198 spin_unlock(&fs_info->trans_lock);
2199 return 0;
2200 }
2201 root = list_first_entry(&fs_info->dead_roots,
2202 struct btrfs_root, root_list);
2203 list_del_init(&root->root_list);
2204 spin_unlock(&fs_info->trans_lock);
2205
2206 pr_debug("BTRFS: cleaner removing %llu\n", root->objectid);
2207
2208 btrfs_kill_all_delayed_nodes(root);
2209
2210 if (btrfs_header_backref_rev(root->node) <
2211 BTRFS_MIXED_BACKREF_REV)
2212 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2213 else
2214 ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2215
2216 return (ret < 0) ? 0 : 1;
2217 }
2218
2219 void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2220 {
2221 unsigned long prev;
2222 unsigned long bit;
2223
2224 prev = xchg(&fs_info->pending_changes, 0);
2225 if (!prev)
2226 return;
2227
2228 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
2229 if (prev & bit)
2230 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2231 prev &= ~bit;
2232
2233 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
2234 if (prev & bit)
2235 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2236 prev &= ~bit;
2237
2238 bit = 1 << BTRFS_PENDING_COMMIT;
2239 if (prev & bit)
2240 btrfs_debug(fs_info, "pending commit done");
2241 prev &= ~bit;
2242
2243 if (prev)
2244 btrfs_warn(fs_info,
2245 "unknown pending changes left 0x%lx, ignoring", prev);
2246 }