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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/sched/mm.h>
10#include <linux/writeback.h>
11#include <linux/pagemap.h>
12#include <linux/blkdev.h>
13#include <linux/uuid.h>
14#include <linux/timekeeping.h>
15#include "misc.h"
16#include "ctree.h"
17#include "disk-io.h"
18#include "transaction.h"
19#include "locking.h"
20#include "tree-log.h"
21#include "volumes.h"
22#include "dev-replace.h"
23#include "qgroup.h"
24#include "block-group.h"
25#include "space-info.h"
26#include "zoned.h"
27#include "fs.h"
28#include "accessors.h"
29#include "extent-tree.h"
30#include "root-tree.h"
31#include "defrag.h"
32#include "dir-item.h"
33#include "uuid-tree.h"
34#include "ioctl.h"
35#include "relocation.h"
36#include "scrub.h"
37
38static struct kmem_cache *btrfs_trans_handle_cachep;
39
40#define BTRFS_ROOT_TRANS_TAG 0
41
42/*
43 * Transaction states and transitions
44 *
45 * No running transaction (fs tree blocks are not modified)
46 * |
47 * | To next stage:
48 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
49 * V
50 * Transaction N [[TRANS_STATE_RUNNING]]
51 * |
52 * | New trans handles can be attached to transaction N by calling all
53 * | start_transaction() variants.
54 * |
55 * | To next stage:
56 * | Call btrfs_commit_transaction() on any trans handle attached to
57 * | transaction N
58 * V
59 * Transaction N [[TRANS_STATE_COMMIT_START]]
60 * |
61 * | Will wait for previous running transaction to completely finish if there
62 * | is one
63 * |
64 * | Then one of the following happes:
65 * | - Wait for all other trans handle holders to release.
66 * | The btrfs_commit_transaction() caller will do the commit work.
67 * | - Wait for current transaction to be committed by others.
68 * | Other btrfs_commit_transaction() caller will do the commit work.
69 * |
70 * | At this stage, only btrfs_join_transaction*() variants can attach
71 * | to this running transaction.
72 * | All other variants will wait for current one to finish and attach to
73 * | transaction N+1.
74 * |
75 * | To next stage:
76 * | Caller is chosen to commit transaction N, and all other trans handle
77 * | haven been released.
78 * V
79 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
80 * |
81 * | The heavy lifting transaction work is started.
82 * | From running delayed refs (modifying extent tree) to creating pending
83 * | snapshots, running qgroups.
84 * | In short, modify supporting trees to reflect modifications of subvolume
85 * | trees.
86 * |
87 * | At this stage, all start_transaction() calls will wait for this
88 * | transaction to finish and attach to transaction N+1.
89 * |
90 * | To next stage:
91 * | Until all supporting trees are updated.
92 * V
93 * Transaction N [[TRANS_STATE_UNBLOCKED]]
94 * | Transaction N+1
95 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
96 * | need to write them back to disk and update |
97 * | super blocks. |
98 * | |
99 * | At this stage, new transaction is allowed to |
100 * | start. |
101 * | All new start_transaction() calls will be |
102 * | attached to transid N+1. |
103 * | |
104 * | To next stage: |
105 * | Until all tree blocks are super blocks are |
106 * | written to block devices |
107 * V |
108 * Transaction N [[TRANS_STATE_COMPLETED]] V
109 * All tree blocks and super blocks are written. Transaction N+1
110 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
111 * data structures will be cleaned up. | Life goes on
112 */
113static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
114 [TRANS_STATE_RUNNING] = 0U,
115 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
116 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
117 __TRANS_ATTACH |
118 __TRANS_JOIN |
119 __TRANS_JOIN_NOSTART),
120 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
121 __TRANS_ATTACH |
122 __TRANS_JOIN |
123 __TRANS_JOIN_NOLOCK |
124 __TRANS_JOIN_NOSTART),
125 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
126 __TRANS_ATTACH |
127 __TRANS_JOIN |
128 __TRANS_JOIN_NOLOCK |
129 __TRANS_JOIN_NOSTART),
130 [TRANS_STATE_COMPLETED] = (__TRANS_START |
131 __TRANS_ATTACH |
132 __TRANS_JOIN |
133 __TRANS_JOIN_NOLOCK |
134 __TRANS_JOIN_NOSTART),
135};
136
137void btrfs_put_transaction(struct btrfs_transaction *transaction)
138{
139 WARN_ON(refcount_read(&transaction->use_count) == 0);
140 if (refcount_dec_and_test(&transaction->use_count)) {
141 BUG_ON(!list_empty(&transaction->list));
142 WARN_ON(!RB_EMPTY_ROOT(
143 &transaction->delayed_refs.href_root.rb_root));
144 WARN_ON(!RB_EMPTY_ROOT(
145 &transaction->delayed_refs.dirty_extent_root));
146 if (transaction->delayed_refs.pending_csums)
147 btrfs_err(transaction->fs_info,
148 "pending csums is %llu",
149 transaction->delayed_refs.pending_csums);
150 /*
151 * If any block groups are found in ->deleted_bgs then it's
152 * because the transaction was aborted and a commit did not
153 * happen (things failed before writing the new superblock
154 * and calling btrfs_finish_extent_commit()), so we can not
155 * discard the physical locations of the block groups.
156 */
157 while (!list_empty(&transaction->deleted_bgs)) {
158 struct btrfs_block_group *cache;
159
160 cache = list_first_entry(&transaction->deleted_bgs,
161 struct btrfs_block_group,
162 bg_list);
163 list_del_init(&cache->bg_list);
164 btrfs_unfreeze_block_group(cache);
165 btrfs_put_block_group(cache);
166 }
167 WARN_ON(!list_empty(&transaction->dev_update_list));
168 kfree(transaction);
169 }
170}
171
172static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
173{
174 struct btrfs_transaction *cur_trans = trans->transaction;
175 struct btrfs_fs_info *fs_info = trans->fs_info;
176 struct btrfs_root *root, *tmp;
177
178 /*
179 * At this point no one can be using this transaction to modify any tree
180 * and no one can start another transaction to modify any tree either.
181 */
182 ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
183
184 down_write(&fs_info->commit_root_sem);
185
186 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
187 fs_info->last_reloc_trans = trans->transid;
188
189 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
190 dirty_list) {
191 list_del_init(&root->dirty_list);
192 free_extent_buffer(root->commit_root);
193 root->commit_root = btrfs_root_node(root);
194 extent_io_tree_release(&root->dirty_log_pages);
195 btrfs_qgroup_clean_swapped_blocks(root);
196 }
197
198 /* We can free old roots now. */
199 spin_lock(&cur_trans->dropped_roots_lock);
200 while (!list_empty(&cur_trans->dropped_roots)) {
201 root = list_first_entry(&cur_trans->dropped_roots,
202 struct btrfs_root, root_list);
203 list_del_init(&root->root_list);
204 spin_unlock(&cur_trans->dropped_roots_lock);
205 btrfs_free_log(trans, root);
206 btrfs_drop_and_free_fs_root(fs_info, root);
207 spin_lock(&cur_trans->dropped_roots_lock);
208 }
209 spin_unlock(&cur_trans->dropped_roots_lock);
210
211 up_write(&fs_info->commit_root_sem);
212}
213
214static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
215 unsigned int type)
216{
217 if (type & TRANS_EXTWRITERS)
218 atomic_inc(&trans->num_extwriters);
219}
220
221static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
222 unsigned int type)
223{
224 if (type & TRANS_EXTWRITERS)
225 atomic_dec(&trans->num_extwriters);
226}
227
228static inline void extwriter_counter_init(struct btrfs_transaction *trans,
229 unsigned int type)
230{
231 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
232}
233
234static inline int extwriter_counter_read(struct btrfs_transaction *trans)
235{
236 return atomic_read(&trans->num_extwriters);
237}
238
239/*
240 * To be called after doing the chunk btree updates right after allocating a new
241 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
242 * chunk after all chunk btree updates and after finishing the second phase of
243 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
244 * group had its chunk item insertion delayed to the second phase.
245 */
246void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
247{
248 struct btrfs_fs_info *fs_info = trans->fs_info;
249
250 if (!trans->chunk_bytes_reserved)
251 return;
252
253 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
254 trans->chunk_bytes_reserved, NULL);
255 trans->chunk_bytes_reserved = 0;
256}
257
258/*
259 * either allocate a new transaction or hop into the existing one
260 */
261static noinline int join_transaction(struct btrfs_fs_info *fs_info,
262 unsigned int type)
263{
264 struct btrfs_transaction *cur_trans;
265
266 spin_lock(&fs_info->trans_lock);
267loop:
268 /* The file system has been taken offline. No new transactions. */
269 if (BTRFS_FS_ERROR(fs_info)) {
270 spin_unlock(&fs_info->trans_lock);
271 return -EROFS;
272 }
273
274 cur_trans = fs_info->running_transaction;
275 if (cur_trans) {
276 if (TRANS_ABORTED(cur_trans)) {
277 spin_unlock(&fs_info->trans_lock);
278 return cur_trans->aborted;
279 }
280 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
281 spin_unlock(&fs_info->trans_lock);
282 return -EBUSY;
283 }
284 refcount_inc(&cur_trans->use_count);
285 atomic_inc(&cur_trans->num_writers);
286 extwriter_counter_inc(cur_trans, type);
287 spin_unlock(&fs_info->trans_lock);
288 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
289 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
290 return 0;
291 }
292 spin_unlock(&fs_info->trans_lock);
293
294 /*
295 * If we are ATTACH, we just want to catch the current transaction,
296 * and commit it. If there is no transaction, just return ENOENT.
297 */
298 if (type == TRANS_ATTACH)
299 return -ENOENT;
300
301 /*
302 * JOIN_NOLOCK only happens during the transaction commit, so
303 * it is impossible that ->running_transaction is NULL
304 */
305 BUG_ON(type == TRANS_JOIN_NOLOCK);
306
307 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
308 if (!cur_trans)
309 return -ENOMEM;
310
311 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
312 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
313
314 spin_lock(&fs_info->trans_lock);
315 if (fs_info->running_transaction) {
316 /*
317 * someone started a transaction after we unlocked. Make sure
318 * to redo the checks above
319 */
320 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
321 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
322 kfree(cur_trans);
323 goto loop;
324 } else if (BTRFS_FS_ERROR(fs_info)) {
325 spin_unlock(&fs_info->trans_lock);
326 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
327 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
328 kfree(cur_trans);
329 return -EROFS;
330 }
331
332 cur_trans->fs_info = fs_info;
333 atomic_set(&cur_trans->pending_ordered, 0);
334 init_waitqueue_head(&cur_trans->pending_wait);
335 atomic_set(&cur_trans->num_writers, 1);
336 extwriter_counter_init(cur_trans, type);
337 init_waitqueue_head(&cur_trans->writer_wait);
338 init_waitqueue_head(&cur_trans->commit_wait);
339 cur_trans->state = TRANS_STATE_RUNNING;
340 /*
341 * One for this trans handle, one so it will live on until we
342 * commit the transaction.
343 */
344 refcount_set(&cur_trans->use_count, 2);
345 cur_trans->flags = 0;
346 cur_trans->start_time = ktime_get_seconds();
347
348 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
349
350 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
351 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
352 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
353
354 /*
355 * although the tree mod log is per file system and not per transaction,
356 * the log must never go across transaction boundaries.
357 */
358 smp_mb();
359 if (!list_empty(&fs_info->tree_mod_seq_list))
360 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
361 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
362 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
363 atomic64_set(&fs_info->tree_mod_seq, 0);
364
365 spin_lock_init(&cur_trans->delayed_refs.lock);
366
367 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
368 INIT_LIST_HEAD(&cur_trans->dev_update_list);
369 INIT_LIST_HEAD(&cur_trans->switch_commits);
370 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
371 INIT_LIST_HEAD(&cur_trans->io_bgs);
372 INIT_LIST_HEAD(&cur_trans->dropped_roots);
373 mutex_init(&cur_trans->cache_write_mutex);
374 spin_lock_init(&cur_trans->dirty_bgs_lock);
375 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
376 spin_lock_init(&cur_trans->dropped_roots_lock);
377 INIT_LIST_HEAD(&cur_trans->releasing_ebs);
378 spin_lock_init(&cur_trans->releasing_ebs_lock);
379 list_add_tail(&cur_trans->list, &fs_info->trans_list);
380 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
381 IO_TREE_TRANS_DIRTY_PAGES);
382 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
383 IO_TREE_FS_PINNED_EXTENTS);
384 fs_info->generation++;
385 cur_trans->transid = fs_info->generation;
386 fs_info->running_transaction = cur_trans;
387 cur_trans->aborted = 0;
388 spin_unlock(&fs_info->trans_lock);
389
390 return 0;
391}
392
393/*
394 * This does all the record keeping required to make sure that a shareable root
395 * is properly recorded in a given transaction. This is required to make sure
396 * the old root from before we joined the transaction is deleted when the
397 * transaction commits.
398 */
399static int record_root_in_trans(struct btrfs_trans_handle *trans,
400 struct btrfs_root *root,
401 int force)
402{
403 struct btrfs_fs_info *fs_info = root->fs_info;
404 int ret = 0;
405
406 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
407 root->last_trans < trans->transid) || force) {
408 WARN_ON(!force && root->commit_root != root->node);
409
410 /*
411 * see below for IN_TRANS_SETUP usage rules
412 * we have the reloc mutex held now, so there
413 * is only one writer in this function
414 */
415 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
416
417 /* make sure readers find IN_TRANS_SETUP before
418 * they find our root->last_trans update
419 */
420 smp_wmb();
421
422 spin_lock(&fs_info->fs_roots_radix_lock);
423 if (root->last_trans == trans->transid && !force) {
424 spin_unlock(&fs_info->fs_roots_radix_lock);
425 return 0;
426 }
427 radix_tree_tag_set(&fs_info->fs_roots_radix,
428 (unsigned long)root->root_key.objectid,
429 BTRFS_ROOT_TRANS_TAG);
430 spin_unlock(&fs_info->fs_roots_radix_lock);
431 root->last_trans = trans->transid;
432
433 /* this is pretty tricky. We don't want to
434 * take the relocation lock in btrfs_record_root_in_trans
435 * unless we're really doing the first setup for this root in
436 * this transaction.
437 *
438 * Normally we'd use root->last_trans as a flag to decide
439 * if we want to take the expensive mutex.
440 *
441 * But, we have to set root->last_trans before we
442 * init the relocation root, otherwise, we trip over warnings
443 * in ctree.c. The solution used here is to flag ourselves
444 * with root IN_TRANS_SETUP. When this is 1, we're still
445 * fixing up the reloc trees and everyone must wait.
446 *
447 * When this is zero, they can trust root->last_trans and fly
448 * through btrfs_record_root_in_trans without having to take the
449 * lock. smp_wmb() makes sure that all the writes above are
450 * done before we pop in the zero below
451 */
452 ret = btrfs_init_reloc_root(trans, root);
453 smp_mb__before_atomic();
454 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
455 }
456 return ret;
457}
458
459
460void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
461 struct btrfs_root *root)
462{
463 struct btrfs_fs_info *fs_info = root->fs_info;
464 struct btrfs_transaction *cur_trans = trans->transaction;
465
466 /* Add ourselves to the transaction dropped list */
467 spin_lock(&cur_trans->dropped_roots_lock);
468 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
469 spin_unlock(&cur_trans->dropped_roots_lock);
470
471 /* Make sure we don't try to update the root at commit time */
472 spin_lock(&fs_info->fs_roots_radix_lock);
473 radix_tree_tag_clear(&fs_info->fs_roots_radix,
474 (unsigned long)root->root_key.objectid,
475 BTRFS_ROOT_TRANS_TAG);
476 spin_unlock(&fs_info->fs_roots_radix_lock);
477}
478
479int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
480 struct btrfs_root *root)
481{
482 struct btrfs_fs_info *fs_info = root->fs_info;
483 int ret;
484
485 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
486 return 0;
487
488 /*
489 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
490 * and barriers
491 */
492 smp_rmb();
493 if (root->last_trans == trans->transid &&
494 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
495 return 0;
496
497 mutex_lock(&fs_info->reloc_mutex);
498 ret = record_root_in_trans(trans, root, 0);
499 mutex_unlock(&fs_info->reloc_mutex);
500
501 return ret;
502}
503
504static inline int is_transaction_blocked(struct btrfs_transaction *trans)
505{
506 return (trans->state >= TRANS_STATE_COMMIT_START &&
507 trans->state < TRANS_STATE_UNBLOCKED &&
508 !TRANS_ABORTED(trans));
509}
510
511/* wait for commit against the current transaction to become unblocked
512 * when this is done, it is safe to start a new transaction, but the current
513 * transaction might not be fully on disk.
514 */
515static void wait_current_trans(struct btrfs_fs_info *fs_info)
516{
517 struct btrfs_transaction *cur_trans;
518
519 spin_lock(&fs_info->trans_lock);
520 cur_trans = fs_info->running_transaction;
521 if (cur_trans && is_transaction_blocked(cur_trans)) {
522 refcount_inc(&cur_trans->use_count);
523 spin_unlock(&fs_info->trans_lock);
524
525 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
526 wait_event(fs_info->transaction_wait,
527 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
528 TRANS_ABORTED(cur_trans));
529 btrfs_put_transaction(cur_trans);
530 } else {
531 spin_unlock(&fs_info->trans_lock);
532 }
533}
534
535static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
536{
537 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
538 return 0;
539
540 if (type == TRANS_START)
541 return 1;
542
543 return 0;
544}
545
546static inline bool need_reserve_reloc_root(struct btrfs_root *root)
547{
548 struct btrfs_fs_info *fs_info = root->fs_info;
549
550 if (!fs_info->reloc_ctl ||
551 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
552 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
553 root->reloc_root)
554 return false;
555
556 return true;
557}
558
559static struct btrfs_trans_handle *
560start_transaction(struct btrfs_root *root, unsigned int num_items,
561 unsigned int type, enum btrfs_reserve_flush_enum flush,
562 bool enforce_qgroups)
563{
564 struct btrfs_fs_info *fs_info = root->fs_info;
565 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
566 struct btrfs_trans_handle *h;
567 struct btrfs_transaction *cur_trans;
568 u64 num_bytes = 0;
569 u64 qgroup_reserved = 0;
570 bool reloc_reserved = false;
571 bool do_chunk_alloc = false;
572 int ret;
573
574 if (BTRFS_FS_ERROR(fs_info))
575 return ERR_PTR(-EROFS);
576
577 if (current->journal_info) {
578 WARN_ON(type & TRANS_EXTWRITERS);
579 h = current->journal_info;
580 refcount_inc(&h->use_count);
581 WARN_ON(refcount_read(&h->use_count) > 2);
582 h->orig_rsv = h->block_rsv;
583 h->block_rsv = NULL;
584 goto got_it;
585 }
586
587 /*
588 * Do the reservation before we join the transaction so we can do all
589 * the appropriate flushing if need be.
590 */
591 if (num_items && root != fs_info->chunk_root) {
592 struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
593 u64 delayed_refs_bytes = 0;
594
595 qgroup_reserved = num_items * fs_info->nodesize;
596 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
597 enforce_qgroups);
598 if (ret)
599 return ERR_PTR(ret);
600
601 /*
602 * We want to reserve all the bytes we may need all at once, so
603 * we only do 1 enospc flushing cycle per transaction start. We
604 * accomplish this by simply assuming we'll do 2 x num_items
605 * worth of delayed refs updates in this trans handle, and
606 * refill that amount for whatever is missing in the reserve.
607 */
608 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
609 if (flush == BTRFS_RESERVE_FLUSH_ALL &&
610 btrfs_block_rsv_full(delayed_refs_rsv) == 0) {
611 delayed_refs_bytes = num_bytes;
612 num_bytes <<= 1;
613 }
614
615 /*
616 * Do the reservation for the relocation root creation
617 */
618 if (need_reserve_reloc_root(root)) {
619 num_bytes += fs_info->nodesize;
620 reloc_reserved = true;
621 }
622
623 ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes, flush);
624 if (ret)
625 goto reserve_fail;
626 if (delayed_refs_bytes) {
627 btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
628 delayed_refs_bytes);
629 num_bytes -= delayed_refs_bytes;
630 }
631
632 if (rsv->space_info->force_alloc)
633 do_chunk_alloc = true;
634 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
635 !btrfs_block_rsv_full(delayed_refs_rsv)) {
636 /*
637 * Some people call with btrfs_start_transaction(root, 0)
638 * because they can be throttled, but have some other mechanism
639 * for reserving space. We still want these guys to refill the
640 * delayed block_rsv so just add 1 items worth of reservation
641 * here.
642 */
643 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
644 if (ret)
645 goto reserve_fail;
646 }
647again:
648 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
649 if (!h) {
650 ret = -ENOMEM;
651 goto alloc_fail;
652 }
653
654 /*
655 * If we are JOIN_NOLOCK we're already committing a transaction and
656 * waiting on this guy, so we don't need to do the sb_start_intwrite
657 * because we're already holding a ref. We need this because we could
658 * have raced in and did an fsync() on a file which can kick a commit
659 * and then we deadlock with somebody doing a freeze.
660 *
661 * If we are ATTACH, it means we just want to catch the current
662 * transaction and commit it, so we needn't do sb_start_intwrite().
663 */
664 if (type & __TRANS_FREEZABLE)
665 sb_start_intwrite(fs_info->sb);
666
667 if (may_wait_transaction(fs_info, type))
668 wait_current_trans(fs_info);
669
670 do {
671 ret = join_transaction(fs_info, type);
672 if (ret == -EBUSY) {
673 wait_current_trans(fs_info);
674 if (unlikely(type == TRANS_ATTACH ||
675 type == TRANS_JOIN_NOSTART))
676 ret = -ENOENT;
677 }
678 } while (ret == -EBUSY);
679
680 if (ret < 0)
681 goto join_fail;
682
683 cur_trans = fs_info->running_transaction;
684
685 h->transid = cur_trans->transid;
686 h->transaction = cur_trans;
687 refcount_set(&h->use_count, 1);
688 h->fs_info = root->fs_info;
689
690 h->type = type;
691 INIT_LIST_HEAD(&h->new_bgs);
692
693 smp_mb();
694 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
695 may_wait_transaction(fs_info, type)) {
696 current->journal_info = h;
697 btrfs_commit_transaction(h);
698 goto again;
699 }
700
701 if (num_bytes) {
702 trace_btrfs_space_reservation(fs_info, "transaction",
703 h->transid, num_bytes, 1);
704 h->block_rsv = &fs_info->trans_block_rsv;
705 h->bytes_reserved = num_bytes;
706 h->reloc_reserved = reloc_reserved;
707 }
708
709got_it:
710 if (!current->journal_info)
711 current->journal_info = h;
712
713 /*
714 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
715 * ALLOC_FORCE the first run through, and then we won't allocate for
716 * anybody else who races in later. We don't care about the return
717 * value here.
718 */
719 if (do_chunk_alloc && num_bytes) {
720 u64 flags = h->block_rsv->space_info->flags;
721
722 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
723 CHUNK_ALLOC_NO_FORCE);
724 }
725
726 /*
727 * btrfs_record_root_in_trans() needs to alloc new extents, and may
728 * call btrfs_join_transaction() while we're also starting a
729 * transaction.
730 *
731 * Thus it need to be called after current->journal_info initialized,
732 * or we can deadlock.
733 */
734 ret = btrfs_record_root_in_trans(h, root);
735 if (ret) {
736 /*
737 * The transaction handle is fully initialized and linked with
738 * other structures so it needs to be ended in case of errors,
739 * not just freed.
740 */
741 btrfs_end_transaction(h);
742 return ERR_PTR(ret);
743 }
744
745 return h;
746
747join_fail:
748 if (type & __TRANS_FREEZABLE)
749 sb_end_intwrite(fs_info->sb);
750 kmem_cache_free(btrfs_trans_handle_cachep, h);
751alloc_fail:
752 if (num_bytes)
753 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
754 num_bytes, NULL);
755reserve_fail:
756 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
757 return ERR_PTR(ret);
758}
759
760struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
761 unsigned int num_items)
762{
763 return start_transaction(root, num_items, TRANS_START,
764 BTRFS_RESERVE_FLUSH_ALL, true);
765}
766
767struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
768 struct btrfs_root *root,
769 unsigned int num_items)
770{
771 return start_transaction(root, num_items, TRANS_START,
772 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
773}
774
775struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
776{
777 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
778 true);
779}
780
781struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
782{
783 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
784 BTRFS_RESERVE_NO_FLUSH, true);
785}
786
787/*
788 * Similar to regular join but it never starts a transaction when none is
789 * running or after waiting for the current one to finish.
790 */
791struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
792{
793 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
794 BTRFS_RESERVE_NO_FLUSH, true);
795}
796
797/*
798 * btrfs_attach_transaction() - catch the running transaction
799 *
800 * It is used when we want to commit the current the transaction, but
801 * don't want to start a new one.
802 *
803 * Note: If this function return -ENOENT, it just means there is no
804 * running transaction. But it is possible that the inactive transaction
805 * is still in the memory, not fully on disk. If you hope there is no
806 * inactive transaction in the fs when -ENOENT is returned, you should
807 * invoke
808 * btrfs_attach_transaction_barrier()
809 */
810struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
811{
812 return start_transaction(root, 0, TRANS_ATTACH,
813 BTRFS_RESERVE_NO_FLUSH, true);
814}
815
816/*
817 * btrfs_attach_transaction_barrier() - catch the running transaction
818 *
819 * It is similar to the above function, the difference is this one
820 * will wait for all the inactive transactions until they fully
821 * complete.
822 */
823struct btrfs_trans_handle *
824btrfs_attach_transaction_barrier(struct btrfs_root *root)
825{
826 struct btrfs_trans_handle *trans;
827
828 trans = start_transaction(root, 0, TRANS_ATTACH,
829 BTRFS_RESERVE_NO_FLUSH, true);
830 if (trans == ERR_PTR(-ENOENT))
831 btrfs_wait_for_commit(root->fs_info, 0);
832
833 return trans;
834}
835
836/* Wait for a transaction commit to reach at least the given state. */
837static noinline void wait_for_commit(struct btrfs_transaction *commit,
838 const enum btrfs_trans_state min_state)
839{
840 struct btrfs_fs_info *fs_info = commit->fs_info;
841 u64 transid = commit->transid;
842 bool put = false;
843
844 /*
845 * At the moment this function is called with min_state either being
846 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
847 */
848 if (min_state == TRANS_STATE_COMPLETED)
849 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
850 else
851 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
852
853 while (1) {
854 wait_event(commit->commit_wait, commit->state >= min_state);
855 if (put)
856 btrfs_put_transaction(commit);
857
858 if (min_state < TRANS_STATE_COMPLETED)
859 break;
860
861 /*
862 * A transaction isn't really completed until all of the
863 * previous transactions are completed, but with fsync we can
864 * end up with SUPER_COMMITTED transactions before a COMPLETED
865 * transaction. Wait for those.
866 */
867
868 spin_lock(&fs_info->trans_lock);
869 commit = list_first_entry_or_null(&fs_info->trans_list,
870 struct btrfs_transaction,
871 list);
872 if (!commit || commit->transid > transid) {
873 spin_unlock(&fs_info->trans_lock);
874 break;
875 }
876 refcount_inc(&commit->use_count);
877 put = true;
878 spin_unlock(&fs_info->trans_lock);
879 }
880}
881
882int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
883{
884 struct btrfs_transaction *cur_trans = NULL, *t;
885 int ret = 0;
886
887 if (transid) {
888 if (transid <= fs_info->last_trans_committed)
889 goto out;
890
891 /* find specified transaction */
892 spin_lock(&fs_info->trans_lock);
893 list_for_each_entry(t, &fs_info->trans_list, list) {
894 if (t->transid == transid) {
895 cur_trans = t;
896 refcount_inc(&cur_trans->use_count);
897 ret = 0;
898 break;
899 }
900 if (t->transid > transid) {
901 ret = 0;
902 break;
903 }
904 }
905 spin_unlock(&fs_info->trans_lock);
906
907 /*
908 * The specified transaction doesn't exist, or we
909 * raced with btrfs_commit_transaction
910 */
911 if (!cur_trans) {
912 if (transid > fs_info->last_trans_committed)
913 ret = -EINVAL;
914 goto out;
915 }
916 } else {
917 /* find newest transaction that is committing | committed */
918 spin_lock(&fs_info->trans_lock);
919 list_for_each_entry_reverse(t, &fs_info->trans_list,
920 list) {
921 if (t->state >= TRANS_STATE_COMMIT_START) {
922 if (t->state == TRANS_STATE_COMPLETED)
923 break;
924 cur_trans = t;
925 refcount_inc(&cur_trans->use_count);
926 break;
927 }
928 }
929 spin_unlock(&fs_info->trans_lock);
930 if (!cur_trans)
931 goto out; /* nothing committing|committed */
932 }
933
934 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
935 btrfs_put_transaction(cur_trans);
936out:
937 return ret;
938}
939
940void btrfs_throttle(struct btrfs_fs_info *fs_info)
941{
942 wait_current_trans(fs_info);
943}
944
945static bool should_end_transaction(struct btrfs_trans_handle *trans)
946{
947 struct btrfs_fs_info *fs_info = trans->fs_info;
948
949 if (btrfs_check_space_for_delayed_refs(fs_info))
950 return true;
951
952 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 50);
953}
954
955bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
956{
957 struct btrfs_transaction *cur_trans = trans->transaction;
958
959 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
960 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
961 return true;
962
963 return should_end_transaction(trans);
964}
965
966static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
967
968{
969 struct btrfs_fs_info *fs_info = trans->fs_info;
970
971 if (!trans->block_rsv) {
972 ASSERT(!trans->bytes_reserved);
973 return;
974 }
975
976 if (!trans->bytes_reserved)
977 return;
978
979 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
980 trace_btrfs_space_reservation(fs_info, "transaction",
981 trans->transid, trans->bytes_reserved, 0);
982 btrfs_block_rsv_release(fs_info, trans->block_rsv,
983 trans->bytes_reserved, NULL);
984 trans->bytes_reserved = 0;
985}
986
987static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
988 int throttle)
989{
990 struct btrfs_fs_info *info = trans->fs_info;
991 struct btrfs_transaction *cur_trans = trans->transaction;
992 int err = 0;
993
994 if (refcount_read(&trans->use_count) > 1) {
995 refcount_dec(&trans->use_count);
996 trans->block_rsv = trans->orig_rsv;
997 return 0;
998 }
999
1000 btrfs_trans_release_metadata(trans);
1001 trans->block_rsv = NULL;
1002
1003 btrfs_create_pending_block_groups(trans);
1004
1005 btrfs_trans_release_chunk_metadata(trans);
1006
1007 if (trans->type & __TRANS_FREEZABLE)
1008 sb_end_intwrite(info->sb);
1009
1010 WARN_ON(cur_trans != info->running_transaction);
1011 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1012 atomic_dec(&cur_trans->num_writers);
1013 extwriter_counter_dec(cur_trans, trans->type);
1014
1015 cond_wake_up(&cur_trans->writer_wait);
1016
1017 btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1018 btrfs_lockdep_release(info, btrfs_trans_num_writers);
1019
1020 btrfs_put_transaction(cur_trans);
1021
1022 if (current->journal_info == trans)
1023 current->journal_info = NULL;
1024
1025 if (throttle)
1026 btrfs_run_delayed_iputs(info);
1027
1028 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1029 wake_up_process(info->transaction_kthread);
1030 if (TRANS_ABORTED(trans))
1031 err = trans->aborted;
1032 else
1033 err = -EROFS;
1034 }
1035
1036 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1037 return err;
1038}
1039
1040int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1041{
1042 return __btrfs_end_transaction(trans, 0);
1043}
1044
1045int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1046{
1047 return __btrfs_end_transaction(trans, 1);
1048}
1049
1050/*
1051 * when btree blocks are allocated, they have some corresponding bits set for
1052 * them in one of two extent_io trees. This is used to make sure all of
1053 * those extents are sent to disk but does not wait on them
1054 */
1055int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1056 struct extent_io_tree *dirty_pages, int mark)
1057{
1058 int err = 0;
1059 int werr = 0;
1060 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1061 struct extent_state *cached_state = NULL;
1062 u64 start = 0;
1063 u64 end;
1064
1065 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1066 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1067 mark, &cached_state)) {
1068 bool wait_writeback = false;
1069
1070 err = convert_extent_bit(dirty_pages, start, end,
1071 EXTENT_NEED_WAIT,
1072 mark, &cached_state);
1073 /*
1074 * convert_extent_bit can return -ENOMEM, which is most of the
1075 * time a temporary error. So when it happens, ignore the error
1076 * and wait for writeback of this range to finish - because we
1077 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1078 * to __btrfs_wait_marked_extents() would not know that
1079 * writeback for this range started and therefore wouldn't
1080 * wait for it to finish - we don't want to commit a
1081 * superblock that points to btree nodes/leafs for which
1082 * writeback hasn't finished yet (and without errors).
1083 * We cleanup any entries left in the io tree when committing
1084 * the transaction (through extent_io_tree_release()).
1085 */
1086 if (err == -ENOMEM) {
1087 err = 0;
1088 wait_writeback = true;
1089 }
1090 if (!err)
1091 err = filemap_fdatawrite_range(mapping, start, end);
1092 if (err)
1093 werr = err;
1094 else if (wait_writeback)
1095 werr = filemap_fdatawait_range(mapping, start, end);
1096 free_extent_state(cached_state);
1097 cached_state = NULL;
1098 cond_resched();
1099 start = end + 1;
1100 }
1101 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1102 return werr;
1103}
1104
1105/*
1106 * when btree blocks are allocated, they have some corresponding bits set for
1107 * them in one of two extent_io trees. This is used to make sure all of
1108 * those extents are on disk for transaction or log commit. We wait
1109 * on all the pages and clear them from the dirty pages state tree
1110 */
1111static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1112 struct extent_io_tree *dirty_pages)
1113{
1114 int err = 0;
1115 int werr = 0;
1116 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1117 struct extent_state *cached_state = NULL;
1118 u64 start = 0;
1119 u64 end;
1120
1121 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1122 EXTENT_NEED_WAIT, &cached_state)) {
1123 /*
1124 * Ignore -ENOMEM errors returned by clear_extent_bit().
1125 * When committing the transaction, we'll remove any entries
1126 * left in the io tree. For a log commit, we don't remove them
1127 * after committing the log because the tree can be accessed
1128 * concurrently - we do it only at transaction commit time when
1129 * it's safe to do it (through extent_io_tree_release()).
1130 */
1131 err = clear_extent_bit(dirty_pages, start, end,
1132 EXTENT_NEED_WAIT, &cached_state);
1133 if (err == -ENOMEM)
1134 err = 0;
1135 if (!err)
1136 err = filemap_fdatawait_range(mapping, start, end);
1137 if (err)
1138 werr = err;
1139 free_extent_state(cached_state);
1140 cached_state = NULL;
1141 cond_resched();
1142 start = end + 1;
1143 }
1144 if (err)
1145 werr = err;
1146 return werr;
1147}
1148
1149static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1150 struct extent_io_tree *dirty_pages)
1151{
1152 bool errors = false;
1153 int err;
1154
1155 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1156 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1157 errors = true;
1158
1159 if (errors && !err)
1160 err = -EIO;
1161 return err;
1162}
1163
1164int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1165{
1166 struct btrfs_fs_info *fs_info = log_root->fs_info;
1167 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1168 bool errors = false;
1169 int err;
1170
1171 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1172
1173 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1174 if ((mark & EXTENT_DIRTY) &&
1175 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1176 errors = true;
1177
1178 if ((mark & EXTENT_NEW) &&
1179 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1180 errors = true;
1181
1182 if (errors && !err)
1183 err = -EIO;
1184 return err;
1185}
1186
1187/*
1188 * When btree blocks are allocated the corresponding extents are marked dirty.
1189 * This function ensures such extents are persisted on disk for transaction or
1190 * log commit.
1191 *
1192 * @trans: transaction whose dirty pages we'd like to write
1193 */
1194static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1195{
1196 int ret;
1197 int ret2;
1198 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1199 struct btrfs_fs_info *fs_info = trans->fs_info;
1200 struct blk_plug plug;
1201
1202 blk_start_plug(&plug);
1203 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1204 blk_finish_plug(&plug);
1205 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1206
1207 extent_io_tree_release(&trans->transaction->dirty_pages);
1208
1209 if (ret)
1210 return ret;
1211 else if (ret2)
1212 return ret2;
1213 else
1214 return 0;
1215}
1216
1217/*
1218 * this is used to update the root pointer in the tree of tree roots.
1219 *
1220 * But, in the case of the extent allocation tree, updating the root
1221 * pointer may allocate blocks which may change the root of the extent
1222 * allocation tree.
1223 *
1224 * So, this loops and repeats and makes sure the cowonly root didn't
1225 * change while the root pointer was being updated in the metadata.
1226 */
1227static int update_cowonly_root(struct btrfs_trans_handle *trans,
1228 struct btrfs_root *root)
1229{
1230 int ret;
1231 u64 old_root_bytenr;
1232 u64 old_root_used;
1233 struct btrfs_fs_info *fs_info = root->fs_info;
1234 struct btrfs_root *tree_root = fs_info->tree_root;
1235
1236 old_root_used = btrfs_root_used(&root->root_item);
1237
1238 while (1) {
1239 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1240 if (old_root_bytenr == root->node->start &&
1241 old_root_used == btrfs_root_used(&root->root_item))
1242 break;
1243
1244 btrfs_set_root_node(&root->root_item, root->node);
1245 ret = btrfs_update_root(trans, tree_root,
1246 &root->root_key,
1247 &root->root_item);
1248 if (ret)
1249 return ret;
1250
1251 old_root_used = btrfs_root_used(&root->root_item);
1252 }
1253
1254 return 0;
1255}
1256
1257/*
1258 * update all the cowonly tree roots on disk
1259 *
1260 * The error handling in this function may not be obvious. Any of the
1261 * failures will cause the file system to go offline. We still need
1262 * to clean up the delayed refs.
1263 */
1264static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1265{
1266 struct btrfs_fs_info *fs_info = trans->fs_info;
1267 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1268 struct list_head *io_bgs = &trans->transaction->io_bgs;
1269 struct list_head *next;
1270 struct extent_buffer *eb;
1271 int ret;
1272
1273 /*
1274 * At this point no one can be using this transaction to modify any tree
1275 * and no one can start another transaction to modify any tree either.
1276 */
1277 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1278
1279 eb = btrfs_lock_root_node(fs_info->tree_root);
1280 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1281 0, &eb, BTRFS_NESTING_COW);
1282 btrfs_tree_unlock(eb);
1283 free_extent_buffer(eb);
1284
1285 if (ret)
1286 return ret;
1287
1288 ret = btrfs_run_dev_stats(trans);
1289 if (ret)
1290 return ret;
1291 ret = btrfs_run_dev_replace(trans);
1292 if (ret)
1293 return ret;
1294 ret = btrfs_run_qgroups(trans);
1295 if (ret)
1296 return ret;
1297
1298 ret = btrfs_setup_space_cache(trans);
1299 if (ret)
1300 return ret;
1301
1302again:
1303 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1304 struct btrfs_root *root;
1305 next = fs_info->dirty_cowonly_roots.next;
1306 list_del_init(next);
1307 root = list_entry(next, struct btrfs_root, dirty_list);
1308 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1309
1310 list_add_tail(&root->dirty_list,
1311 &trans->transaction->switch_commits);
1312 ret = update_cowonly_root(trans, root);
1313 if (ret)
1314 return ret;
1315 }
1316
1317 /* Now flush any delayed refs generated by updating all of the roots */
1318 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1319 if (ret)
1320 return ret;
1321
1322 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1323 ret = btrfs_write_dirty_block_groups(trans);
1324 if (ret)
1325 return ret;
1326
1327 /*
1328 * We're writing the dirty block groups, which could generate
1329 * delayed refs, which could generate more dirty block groups,
1330 * so we want to keep this flushing in this loop to make sure
1331 * everything gets run.
1332 */
1333 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1334 if (ret)
1335 return ret;
1336 }
1337
1338 if (!list_empty(&fs_info->dirty_cowonly_roots))
1339 goto again;
1340
1341 /* Update dev-replace pointer once everything is committed */
1342 fs_info->dev_replace.committed_cursor_left =
1343 fs_info->dev_replace.cursor_left_last_write_of_item;
1344
1345 return 0;
1346}
1347
1348/*
1349 * If we had a pending drop we need to see if there are any others left in our
1350 * dead roots list, and if not clear our bit and wake any waiters.
1351 */
1352void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1353{
1354 /*
1355 * We put the drop in progress roots at the front of the list, so if the
1356 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1357 * up.
1358 */
1359 spin_lock(&fs_info->trans_lock);
1360 if (!list_empty(&fs_info->dead_roots)) {
1361 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1362 struct btrfs_root,
1363 root_list);
1364 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1365 spin_unlock(&fs_info->trans_lock);
1366 return;
1367 }
1368 }
1369 spin_unlock(&fs_info->trans_lock);
1370
1371 btrfs_wake_unfinished_drop(fs_info);
1372}
1373
1374/*
1375 * dead roots are old snapshots that need to be deleted. This allocates
1376 * a dirty root struct and adds it into the list of dead roots that need to
1377 * be deleted
1378 */
1379void btrfs_add_dead_root(struct btrfs_root *root)
1380{
1381 struct btrfs_fs_info *fs_info = root->fs_info;
1382
1383 spin_lock(&fs_info->trans_lock);
1384 if (list_empty(&root->root_list)) {
1385 btrfs_grab_root(root);
1386
1387 /* We want to process the partially complete drops first. */
1388 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1389 list_add(&root->root_list, &fs_info->dead_roots);
1390 else
1391 list_add_tail(&root->root_list, &fs_info->dead_roots);
1392 }
1393 spin_unlock(&fs_info->trans_lock);
1394}
1395
1396/*
1397 * Update each subvolume root and its relocation root, if it exists, in the tree
1398 * of tree roots. Also free log roots if they exist.
1399 */
1400static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1401{
1402 struct btrfs_fs_info *fs_info = trans->fs_info;
1403 struct btrfs_root *gang[8];
1404 int i;
1405 int ret;
1406
1407 /*
1408 * At this point no one can be using this transaction to modify any tree
1409 * and no one can start another transaction to modify any tree either.
1410 */
1411 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1412
1413 spin_lock(&fs_info->fs_roots_radix_lock);
1414 while (1) {
1415 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1416 (void **)gang, 0,
1417 ARRAY_SIZE(gang),
1418 BTRFS_ROOT_TRANS_TAG);
1419 if (ret == 0)
1420 break;
1421 for (i = 0; i < ret; i++) {
1422 struct btrfs_root *root = gang[i];
1423 int ret2;
1424
1425 /*
1426 * At this point we can neither have tasks logging inodes
1427 * from a root nor trying to commit a log tree.
1428 */
1429 ASSERT(atomic_read(&root->log_writers) == 0);
1430 ASSERT(atomic_read(&root->log_commit[0]) == 0);
1431 ASSERT(atomic_read(&root->log_commit[1]) == 0);
1432
1433 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1434 (unsigned long)root->root_key.objectid,
1435 BTRFS_ROOT_TRANS_TAG);
1436 spin_unlock(&fs_info->fs_roots_radix_lock);
1437
1438 btrfs_free_log(trans, root);
1439 ret2 = btrfs_update_reloc_root(trans, root);
1440 if (ret2)
1441 return ret2;
1442
1443 /* see comments in should_cow_block() */
1444 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1445 smp_mb__after_atomic();
1446
1447 if (root->commit_root != root->node) {
1448 list_add_tail(&root->dirty_list,
1449 &trans->transaction->switch_commits);
1450 btrfs_set_root_node(&root->root_item,
1451 root->node);
1452 }
1453
1454 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1455 &root->root_key,
1456 &root->root_item);
1457 if (ret2)
1458 return ret2;
1459 spin_lock(&fs_info->fs_roots_radix_lock);
1460 btrfs_qgroup_free_meta_all_pertrans(root);
1461 }
1462 }
1463 spin_unlock(&fs_info->fs_roots_radix_lock);
1464 return 0;
1465}
1466
1467/*
1468 * defrag a given btree.
1469 * Every leaf in the btree is read and defragged.
1470 */
1471int btrfs_defrag_root(struct btrfs_root *root)
1472{
1473 struct btrfs_fs_info *info = root->fs_info;
1474 struct btrfs_trans_handle *trans;
1475 int ret;
1476
1477 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1478 return 0;
1479
1480 while (1) {
1481 trans = btrfs_start_transaction(root, 0);
1482 if (IS_ERR(trans)) {
1483 ret = PTR_ERR(trans);
1484 break;
1485 }
1486
1487 ret = btrfs_defrag_leaves(trans, root);
1488
1489 btrfs_end_transaction(trans);
1490 btrfs_btree_balance_dirty(info);
1491 cond_resched();
1492
1493 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1494 break;
1495
1496 if (btrfs_defrag_cancelled(info)) {
1497 btrfs_debug(info, "defrag_root cancelled");
1498 ret = -EAGAIN;
1499 break;
1500 }
1501 }
1502 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1503 return ret;
1504}
1505
1506/*
1507 * Do all special snapshot related qgroup dirty hack.
1508 *
1509 * Will do all needed qgroup inherit and dirty hack like switch commit
1510 * roots inside one transaction and write all btree into disk, to make
1511 * qgroup works.
1512 */
1513static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1514 struct btrfs_root *src,
1515 struct btrfs_root *parent,
1516 struct btrfs_qgroup_inherit *inherit,
1517 u64 dst_objectid)
1518{
1519 struct btrfs_fs_info *fs_info = src->fs_info;
1520 int ret;
1521
1522 /*
1523 * Save some performance in the case that qgroups are not
1524 * enabled. If this check races with the ioctl, rescan will
1525 * kick in anyway.
1526 */
1527 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1528 return 0;
1529
1530 /*
1531 * Ensure dirty @src will be committed. Or, after coming
1532 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1533 * recorded root will never be updated again, causing an outdated root
1534 * item.
1535 */
1536 ret = record_root_in_trans(trans, src, 1);
1537 if (ret)
1538 return ret;
1539
1540 /*
1541 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1542 * src root, so we must run the delayed refs here.
1543 *
1544 * However this isn't particularly fool proof, because there's no
1545 * synchronization keeping us from changing the tree after this point
1546 * before we do the qgroup_inherit, or even from making changes while
1547 * we're doing the qgroup_inherit. But that's a problem for the future,
1548 * for now flush the delayed refs to narrow the race window where the
1549 * qgroup counters could end up wrong.
1550 */
1551 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1552 if (ret) {
1553 btrfs_abort_transaction(trans, ret);
1554 return ret;
1555 }
1556
1557 ret = commit_fs_roots(trans);
1558 if (ret)
1559 goto out;
1560 ret = btrfs_qgroup_account_extents(trans);
1561 if (ret < 0)
1562 goto out;
1563
1564 /* Now qgroup are all updated, we can inherit it to new qgroups */
1565 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1566 inherit);
1567 if (ret < 0)
1568 goto out;
1569
1570 /*
1571 * Now we do a simplified commit transaction, which will:
1572 * 1) commit all subvolume and extent tree
1573 * To ensure all subvolume and extent tree have a valid
1574 * commit_root to accounting later insert_dir_item()
1575 * 2) write all btree blocks onto disk
1576 * This is to make sure later btree modification will be cowed
1577 * Or commit_root can be populated and cause wrong qgroup numbers
1578 * In this simplified commit, we don't really care about other trees
1579 * like chunk and root tree, as they won't affect qgroup.
1580 * And we don't write super to avoid half committed status.
1581 */
1582 ret = commit_cowonly_roots(trans);
1583 if (ret)
1584 goto out;
1585 switch_commit_roots(trans);
1586 ret = btrfs_write_and_wait_transaction(trans);
1587 if (ret)
1588 btrfs_handle_fs_error(fs_info, ret,
1589 "Error while writing out transaction for qgroup");
1590
1591out:
1592 /*
1593 * Force parent root to be updated, as we recorded it before so its
1594 * last_trans == cur_transid.
1595 * Or it won't be committed again onto disk after later
1596 * insert_dir_item()
1597 */
1598 if (!ret)
1599 ret = record_root_in_trans(trans, parent, 1);
1600 return ret;
1601}
1602
1603/*
1604 * new snapshots need to be created at a very specific time in the
1605 * transaction commit. This does the actual creation.
1606 *
1607 * Note:
1608 * If the error which may affect the commitment of the current transaction
1609 * happens, we should return the error number. If the error which just affect
1610 * the creation of the pending snapshots, just return 0.
1611 */
1612static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1613 struct btrfs_pending_snapshot *pending)
1614{
1615
1616 struct btrfs_fs_info *fs_info = trans->fs_info;
1617 struct btrfs_key key;
1618 struct btrfs_root_item *new_root_item;
1619 struct btrfs_root *tree_root = fs_info->tree_root;
1620 struct btrfs_root *root = pending->root;
1621 struct btrfs_root *parent_root;
1622 struct btrfs_block_rsv *rsv;
1623 struct inode *parent_inode = pending->dir;
1624 struct btrfs_path *path;
1625 struct btrfs_dir_item *dir_item;
1626 struct extent_buffer *tmp;
1627 struct extent_buffer *old;
1628 struct timespec64 cur_time;
1629 int ret = 0;
1630 u64 to_reserve = 0;
1631 u64 index = 0;
1632 u64 objectid;
1633 u64 root_flags;
1634 unsigned int nofs_flags;
1635 struct fscrypt_name fname;
1636
1637 ASSERT(pending->path);
1638 path = pending->path;
1639
1640 ASSERT(pending->root_item);
1641 new_root_item = pending->root_item;
1642
1643 /*
1644 * We're inside a transaction and must make sure that any potential
1645 * allocations with GFP_KERNEL in fscrypt won't recurse back to
1646 * filesystem.
1647 */
1648 nofs_flags = memalloc_nofs_save();
1649 pending->error = fscrypt_setup_filename(parent_inode,
1650 &pending->dentry->d_name, 0,
1651 &fname);
1652 memalloc_nofs_restore(nofs_flags);
1653 if (pending->error)
1654 goto free_pending;
1655
1656 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1657 if (pending->error)
1658 goto free_fname;
1659
1660 /*
1661 * Make qgroup to skip current new snapshot's qgroupid, as it is
1662 * accounted by later btrfs_qgroup_inherit().
1663 */
1664 btrfs_set_skip_qgroup(trans, objectid);
1665
1666 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1667
1668 if (to_reserve > 0) {
1669 pending->error = btrfs_block_rsv_add(fs_info,
1670 &pending->block_rsv,
1671 to_reserve,
1672 BTRFS_RESERVE_NO_FLUSH);
1673 if (pending->error)
1674 goto clear_skip_qgroup;
1675 }
1676
1677 key.objectid = objectid;
1678 key.offset = (u64)-1;
1679 key.type = BTRFS_ROOT_ITEM_KEY;
1680
1681 rsv = trans->block_rsv;
1682 trans->block_rsv = &pending->block_rsv;
1683 trans->bytes_reserved = trans->block_rsv->reserved;
1684 trace_btrfs_space_reservation(fs_info, "transaction",
1685 trans->transid,
1686 trans->bytes_reserved, 1);
1687 parent_root = BTRFS_I(parent_inode)->root;
1688 ret = record_root_in_trans(trans, parent_root, 0);
1689 if (ret)
1690 goto fail;
1691 cur_time = current_time(parent_inode);
1692
1693 /*
1694 * insert the directory item
1695 */
1696 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1697 BUG_ON(ret); /* -ENOMEM */
1698
1699 /* check if there is a file/dir which has the same name. */
1700 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1701 btrfs_ino(BTRFS_I(parent_inode)),
1702 &fname.disk_name, 0);
1703 if (dir_item != NULL && !IS_ERR(dir_item)) {
1704 pending->error = -EEXIST;
1705 goto dir_item_existed;
1706 } else if (IS_ERR(dir_item)) {
1707 ret = PTR_ERR(dir_item);
1708 btrfs_abort_transaction(trans, ret);
1709 goto fail;
1710 }
1711 btrfs_release_path(path);
1712
1713 /*
1714 * pull in the delayed directory update
1715 * and the delayed inode item
1716 * otherwise we corrupt the FS during
1717 * snapshot
1718 */
1719 ret = btrfs_run_delayed_items(trans);
1720 if (ret) { /* Transaction aborted */
1721 btrfs_abort_transaction(trans, ret);
1722 goto fail;
1723 }
1724
1725 ret = record_root_in_trans(trans, root, 0);
1726 if (ret) {
1727 btrfs_abort_transaction(trans, ret);
1728 goto fail;
1729 }
1730 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1731 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1732 btrfs_check_and_init_root_item(new_root_item);
1733
1734 root_flags = btrfs_root_flags(new_root_item);
1735 if (pending->readonly)
1736 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1737 else
1738 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1739 btrfs_set_root_flags(new_root_item, root_flags);
1740
1741 btrfs_set_root_generation_v2(new_root_item,
1742 trans->transid);
1743 generate_random_guid(new_root_item->uuid);
1744 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1745 BTRFS_UUID_SIZE);
1746 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1747 memset(new_root_item->received_uuid, 0,
1748 sizeof(new_root_item->received_uuid));
1749 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1750 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1751 btrfs_set_root_stransid(new_root_item, 0);
1752 btrfs_set_root_rtransid(new_root_item, 0);
1753 }
1754 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1755 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1756 btrfs_set_root_otransid(new_root_item, trans->transid);
1757
1758 old = btrfs_lock_root_node(root);
1759 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1760 BTRFS_NESTING_COW);
1761 if (ret) {
1762 btrfs_tree_unlock(old);
1763 free_extent_buffer(old);
1764 btrfs_abort_transaction(trans, ret);
1765 goto fail;
1766 }
1767
1768 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1769 /* clean up in any case */
1770 btrfs_tree_unlock(old);
1771 free_extent_buffer(old);
1772 if (ret) {
1773 btrfs_abort_transaction(trans, ret);
1774 goto fail;
1775 }
1776 /* see comments in should_cow_block() */
1777 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1778 smp_wmb();
1779
1780 btrfs_set_root_node(new_root_item, tmp);
1781 /* record when the snapshot was created in key.offset */
1782 key.offset = trans->transid;
1783 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1784 btrfs_tree_unlock(tmp);
1785 free_extent_buffer(tmp);
1786 if (ret) {
1787 btrfs_abort_transaction(trans, ret);
1788 goto fail;
1789 }
1790
1791 /*
1792 * insert root back/forward references
1793 */
1794 ret = btrfs_add_root_ref(trans, objectid,
1795 parent_root->root_key.objectid,
1796 btrfs_ino(BTRFS_I(parent_inode)), index,
1797 &fname.disk_name);
1798 if (ret) {
1799 btrfs_abort_transaction(trans, ret);
1800 goto fail;
1801 }
1802
1803 key.offset = (u64)-1;
1804 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1805 if (IS_ERR(pending->snap)) {
1806 ret = PTR_ERR(pending->snap);
1807 pending->snap = NULL;
1808 btrfs_abort_transaction(trans, ret);
1809 goto fail;
1810 }
1811
1812 ret = btrfs_reloc_post_snapshot(trans, pending);
1813 if (ret) {
1814 btrfs_abort_transaction(trans, ret);
1815 goto fail;
1816 }
1817
1818 /*
1819 * Do special qgroup accounting for snapshot, as we do some qgroup
1820 * snapshot hack to do fast snapshot.
1821 * To co-operate with that hack, we do hack again.
1822 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1823 */
1824 ret = qgroup_account_snapshot(trans, root, parent_root,
1825 pending->inherit, objectid);
1826 if (ret < 0)
1827 goto fail;
1828
1829 ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1830 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1831 index);
1832 /* We have check then name at the beginning, so it is impossible. */
1833 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1834 if (ret) {
1835 btrfs_abort_transaction(trans, ret);
1836 goto fail;
1837 }
1838
1839 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1840 fname.disk_name.len * 2);
1841 parent_inode->i_mtime = current_time(parent_inode);
1842 parent_inode->i_ctime = parent_inode->i_mtime;
1843 ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
1844 if (ret) {
1845 btrfs_abort_transaction(trans, ret);
1846 goto fail;
1847 }
1848 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1849 BTRFS_UUID_KEY_SUBVOL,
1850 objectid);
1851 if (ret) {
1852 btrfs_abort_transaction(trans, ret);
1853 goto fail;
1854 }
1855 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1856 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1857 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1858 objectid);
1859 if (ret && ret != -EEXIST) {
1860 btrfs_abort_transaction(trans, ret);
1861 goto fail;
1862 }
1863 }
1864
1865fail:
1866 pending->error = ret;
1867dir_item_existed:
1868 trans->block_rsv = rsv;
1869 trans->bytes_reserved = 0;
1870clear_skip_qgroup:
1871 btrfs_clear_skip_qgroup(trans);
1872free_fname:
1873 fscrypt_free_filename(&fname);
1874free_pending:
1875 kfree(new_root_item);
1876 pending->root_item = NULL;
1877 btrfs_free_path(path);
1878 pending->path = NULL;
1879
1880 return ret;
1881}
1882
1883/*
1884 * create all the snapshots we've scheduled for creation
1885 */
1886static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1887{
1888 struct btrfs_pending_snapshot *pending, *next;
1889 struct list_head *head = &trans->transaction->pending_snapshots;
1890 int ret = 0;
1891
1892 list_for_each_entry_safe(pending, next, head, list) {
1893 list_del(&pending->list);
1894 ret = create_pending_snapshot(trans, pending);
1895 if (ret)
1896 break;
1897 }
1898 return ret;
1899}
1900
1901static void update_super_roots(struct btrfs_fs_info *fs_info)
1902{
1903 struct btrfs_root_item *root_item;
1904 struct btrfs_super_block *super;
1905
1906 super = fs_info->super_copy;
1907
1908 root_item = &fs_info->chunk_root->root_item;
1909 super->chunk_root = root_item->bytenr;
1910 super->chunk_root_generation = root_item->generation;
1911 super->chunk_root_level = root_item->level;
1912
1913 root_item = &fs_info->tree_root->root_item;
1914 super->root = root_item->bytenr;
1915 super->generation = root_item->generation;
1916 super->root_level = root_item->level;
1917 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1918 super->cache_generation = root_item->generation;
1919 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1920 super->cache_generation = 0;
1921 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1922 super->uuid_tree_generation = root_item->generation;
1923}
1924
1925int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1926{
1927 struct btrfs_transaction *trans;
1928 int ret = 0;
1929
1930 spin_lock(&info->trans_lock);
1931 trans = info->running_transaction;
1932 if (trans)
1933 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1934 spin_unlock(&info->trans_lock);
1935 return ret;
1936}
1937
1938int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1939{
1940 struct btrfs_transaction *trans;
1941 int ret = 0;
1942
1943 spin_lock(&info->trans_lock);
1944 trans = info->running_transaction;
1945 if (trans)
1946 ret = is_transaction_blocked(trans);
1947 spin_unlock(&info->trans_lock);
1948 return ret;
1949}
1950
1951void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1952{
1953 struct btrfs_fs_info *fs_info = trans->fs_info;
1954 struct btrfs_transaction *cur_trans;
1955
1956 /* Kick the transaction kthread. */
1957 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1958 wake_up_process(fs_info->transaction_kthread);
1959
1960 /* take transaction reference */
1961 cur_trans = trans->transaction;
1962 refcount_inc(&cur_trans->use_count);
1963
1964 btrfs_end_transaction(trans);
1965
1966 /*
1967 * Wait for the current transaction commit to start and block
1968 * subsequent transaction joins
1969 */
1970 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
1971 wait_event(fs_info->transaction_blocked_wait,
1972 cur_trans->state >= TRANS_STATE_COMMIT_START ||
1973 TRANS_ABORTED(cur_trans));
1974 btrfs_put_transaction(cur_trans);
1975}
1976
1977static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1978{
1979 struct btrfs_fs_info *fs_info = trans->fs_info;
1980 struct btrfs_transaction *cur_trans = trans->transaction;
1981
1982 WARN_ON(refcount_read(&trans->use_count) > 1);
1983
1984 btrfs_abort_transaction(trans, err);
1985
1986 spin_lock(&fs_info->trans_lock);
1987
1988 /*
1989 * If the transaction is removed from the list, it means this
1990 * transaction has been committed successfully, so it is impossible
1991 * to call the cleanup function.
1992 */
1993 BUG_ON(list_empty(&cur_trans->list));
1994
1995 if (cur_trans == fs_info->running_transaction) {
1996 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1997 spin_unlock(&fs_info->trans_lock);
1998
1999 /*
2000 * The thread has already released the lockdep map as reader
2001 * already in btrfs_commit_transaction().
2002 */
2003 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2004 wait_event(cur_trans->writer_wait,
2005 atomic_read(&cur_trans->num_writers) == 1);
2006
2007 spin_lock(&fs_info->trans_lock);
2008 }
2009
2010 /*
2011 * Now that we know no one else is still using the transaction we can
2012 * remove the transaction from the list of transactions. This avoids
2013 * the transaction kthread from cleaning up the transaction while some
2014 * other task is still using it, which could result in a use-after-free
2015 * on things like log trees, as it forces the transaction kthread to
2016 * wait for this transaction to be cleaned up by us.
2017 */
2018 list_del_init(&cur_trans->list);
2019
2020 spin_unlock(&fs_info->trans_lock);
2021
2022 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
2023
2024 spin_lock(&fs_info->trans_lock);
2025 if (cur_trans == fs_info->running_transaction)
2026 fs_info->running_transaction = NULL;
2027 spin_unlock(&fs_info->trans_lock);
2028
2029 if (trans->type & __TRANS_FREEZABLE)
2030 sb_end_intwrite(fs_info->sb);
2031 btrfs_put_transaction(cur_trans);
2032 btrfs_put_transaction(cur_trans);
2033
2034 trace_btrfs_transaction_commit(fs_info);
2035
2036 if (current->journal_info == trans)
2037 current->journal_info = NULL;
2038 btrfs_scrub_cancel(fs_info);
2039
2040 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2041}
2042
2043/*
2044 * Release reserved delayed ref space of all pending block groups of the
2045 * transaction and remove them from the list
2046 */
2047static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2048{
2049 struct btrfs_fs_info *fs_info = trans->fs_info;
2050 struct btrfs_block_group *block_group, *tmp;
2051
2052 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2053 btrfs_delayed_refs_rsv_release(fs_info, 1);
2054 list_del_init(&block_group->bg_list);
2055 }
2056}
2057
2058static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2059{
2060 /*
2061 * We use try_to_writeback_inodes_sb() here because if we used
2062 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2063 * Currently are holding the fs freeze lock, if we do an async flush
2064 * we'll do btrfs_join_transaction() and deadlock because we need to
2065 * wait for the fs freeze lock. Using the direct flushing we benefit
2066 * from already being in a transaction and our join_transaction doesn't
2067 * have to re-take the fs freeze lock.
2068 *
2069 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2070 * if it can read lock sb->s_umount. It will always be able to lock it,
2071 * except when the filesystem is being unmounted or being frozen, but in
2072 * those cases sync_filesystem() is called, which results in calling
2073 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2074 * Note that we don't call writeback_inodes_sb() directly, because it
2075 * will emit a warning if sb->s_umount is not locked.
2076 */
2077 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2078 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2079 return 0;
2080}
2081
2082static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2083{
2084 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2085 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2086}
2087
2088/*
2089 * Add a pending snapshot associated with the given transaction handle to the
2090 * respective handle. This must be called after the transaction commit started
2091 * and while holding fs_info->trans_lock.
2092 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2093 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2094 * returns an error.
2095 */
2096static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2097{
2098 struct btrfs_transaction *cur_trans = trans->transaction;
2099
2100 if (!trans->pending_snapshot)
2101 return;
2102
2103 lockdep_assert_held(&trans->fs_info->trans_lock);
2104 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START);
2105
2106 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2107}
2108
2109static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
2110{
2111 fs_info->commit_stats.commit_count++;
2112 fs_info->commit_stats.last_commit_dur = interval;
2113 fs_info->commit_stats.max_commit_dur =
2114 max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2115 fs_info->commit_stats.total_commit_dur += interval;
2116}
2117
2118int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2119{
2120 struct btrfs_fs_info *fs_info = trans->fs_info;
2121 struct btrfs_transaction *cur_trans = trans->transaction;
2122 struct btrfs_transaction *prev_trans = NULL;
2123 int ret;
2124 ktime_t start_time;
2125 ktime_t interval;
2126
2127 ASSERT(refcount_read(&trans->use_count) == 1);
2128 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2129
2130 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2131
2132 /* Stop the commit early if ->aborted is set */
2133 if (TRANS_ABORTED(cur_trans)) {
2134 ret = cur_trans->aborted;
2135 goto lockdep_trans_commit_start_release;
2136 }
2137
2138 btrfs_trans_release_metadata(trans);
2139 trans->block_rsv = NULL;
2140
2141 /*
2142 * We only want one transaction commit doing the flushing so we do not
2143 * waste a bunch of time on lock contention on the extent root node.
2144 */
2145 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2146 &cur_trans->delayed_refs.flags)) {
2147 /*
2148 * Make a pass through all the delayed refs we have so far.
2149 * Any running threads may add more while we are here.
2150 */
2151 ret = btrfs_run_delayed_refs(trans, 0);
2152 if (ret)
2153 goto lockdep_trans_commit_start_release;
2154 }
2155
2156 btrfs_create_pending_block_groups(trans);
2157
2158 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2159 int run_it = 0;
2160
2161 /* this mutex is also taken before trying to set
2162 * block groups readonly. We need to make sure
2163 * that nobody has set a block group readonly
2164 * after a extents from that block group have been
2165 * allocated for cache files. btrfs_set_block_group_ro
2166 * will wait for the transaction to commit if it
2167 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2168 *
2169 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2170 * only one process starts all the block group IO. It wouldn't
2171 * hurt to have more than one go through, but there's no
2172 * real advantage to it either.
2173 */
2174 mutex_lock(&fs_info->ro_block_group_mutex);
2175 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2176 &cur_trans->flags))
2177 run_it = 1;
2178 mutex_unlock(&fs_info->ro_block_group_mutex);
2179
2180 if (run_it) {
2181 ret = btrfs_start_dirty_block_groups(trans);
2182 if (ret)
2183 goto lockdep_trans_commit_start_release;
2184 }
2185 }
2186
2187 spin_lock(&fs_info->trans_lock);
2188 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2189 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2190
2191 add_pending_snapshot(trans);
2192
2193 spin_unlock(&fs_info->trans_lock);
2194 refcount_inc(&cur_trans->use_count);
2195
2196 if (trans->in_fsync)
2197 want_state = TRANS_STATE_SUPER_COMMITTED;
2198
2199 btrfs_trans_state_lockdep_release(fs_info,
2200 BTRFS_LOCKDEP_TRANS_COMMIT_START);
2201 ret = btrfs_end_transaction(trans);
2202 wait_for_commit(cur_trans, want_state);
2203
2204 if (TRANS_ABORTED(cur_trans))
2205 ret = cur_trans->aborted;
2206
2207 btrfs_put_transaction(cur_trans);
2208
2209 return ret;
2210 }
2211
2212 cur_trans->state = TRANS_STATE_COMMIT_START;
2213 wake_up(&fs_info->transaction_blocked_wait);
2214 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2215
2216 if (cur_trans->list.prev != &fs_info->trans_list) {
2217 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2218
2219 if (trans->in_fsync)
2220 want_state = TRANS_STATE_SUPER_COMMITTED;
2221
2222 prev_trans = list_entry(cur_trans->list.prev,
2223 struct btrfs_transaction, list);
2224 if (prev_trans->state < want_state) {
2225 refcount_inc(&prev_trans->use_count);
2226 spin_unlock(&fs_info->trans_lock);
2227
2228 wait_for_commit(prev_trans, want_state);
2229
2230 ret = READ_ONCE(prev_trans->aborted);
2231
2232 btrfs_put_transaction(prev_trans);
2233 if (ret)
2234 goto lockdep_release;
2235 } else {
2236 spin_unlock(&fs_info->trans_lock);
2237 }
2238 } else {
2239 spin_unlock(&fs_info->trans_lock);
2240 /*
2241 * The previous transaction was aborted and was already removed
2242 * from the list of transactions at fs_info->trans_list. So we
2243 * abort to prevent writing a new superblock that reflects a
2244 * corrupt state (pointing to trees with unwritten nodes/leafs).
2245 */
2246 if (BTRFS_FS_ERROR(fs_info)) {
2247 ret = -EROFS;
2248 goto lockdep_release;
2249 }
2250 }
2251
2252 /*
2253 * Get the time spent on the work done by the commit thread and not
2254 * the time spent waiting on a previous commit
2255 */
2256 start_time = ktime_get_ns();
2257
2258 extwriter_counter_dec(cur_trans, trans->type);
2259
2260 ret = btrfs_start_delalloc_flush(fs_info);
2261 if (ret)
2262 goto lockdep_release;
2263
2264 ret = btrfs_run_delayed_items(trans);
2265 if (ret)
2266 goto lockdep_release;
2267
2268 /*
2269 * The thread has started/joined the transaction thus it holds the
2270 * lockdep map as a reader. It has to release it before acquiring the
2271 * lockdep map as a writer.
2272 */
2273 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2274 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2275 wait_event(cur_trans->writer_wait,
2276 extwriter_counter_read(cur_trans) == 0);
2277
2278 /* some pending stuffs might be added after the previous flush. */
2279 ret = btrfs_run_delayed_items(trans);
2280 if (ret) {
2281 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2282 goto cleanup_transaction;
2283 }
2284
2285 btrfs_wait_delalloc_flush(fs_info);
2286
2287 /*
2288 * Wait for all ordered extents started by a fast fsync that joined this
2289 * transaction. Otherwise if this transaction commits before the ordered
2290 * extents complete we lose logged data after a power failure.
2291 */
2292 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2293 wait_event(cur_trans->pending_wait,
2294 atomic_read(&cur_trans->pending_ordered) == 0);
2295
2296 btrfs_scrub_pause(fs_info);
2297 /*
2298 * Ok now we need to make sure to block out any other joins while we
2299 * commit the transaction. We could have started a join before setting
2300 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2301 */
2302 spin_lock(&fs_info->trans_lock);
2303 add_pending_snapshot(trans);
2304 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2305 spin_unlock(&fs_info->trans_lock);
2306
2307 /*
2308 * The thread has started/joined the transaction thus it holds the
2309 * lockdep map as a reader. It has to release it before acquiring the
2310 * lockdep map as a writer.
2311 */
2312 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2313 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2314 wait_event(cur_trans->writer_wait,
2315 atomic_read(&cur_trans->num_writers) == 1);
2316
2317 /*
2318 * Make lockdep happy by acquiring the state locks after
2319 * btrfs_trans_num_writers is released. If we acquired the state locks
2320 * before releasing the btrfs_trans_num_writers lock then lockdep would
2321 * complain because we did not follow the reverse order unlocking rule.
2322 */
2323 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2324 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2325 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2326
2327 /*
2328 * We've started the commit, clear the flag in case we were triggered to
2329 * do an async commit but somebody else started before the transaction
2330 * kthread could do the work.
2331 */
2332 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2333
2334 if (TRANS_ABORTED(cur_trans)) {
2335 ret = cur_trans->aborted;
2336 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2337 goto scrub_continue;
2338 }
2339 /*
2340 * the reloc mutex makes sure that we stop
2341 * the balancing code from coming in and moving
2342 * extents around in the middle of the commit
2343 */
2344 mutex_lock(&fs_info->reloc_mutex);
2345
2346 /*
2347 * We needn't worry about the delayed items because we will
2348 * deal with them in create_pending_snapshot(), which is the
2349 * core function of the snapshot creation.
2350 */
2351 ret = create_pending_snapshots(trans);
2352 if (ret)
2353 goto unlock_reloc;
2354
2355 /*
2356 * We insert the dir indexes of the snapshots and update the inode
2357 * of the snapshots' parents after the snapshot creation, so there
2358 * are some delayed items which are not dealt with. Now deal with
2359 * them.
2360 *
2361 * We needn't worry that this operation will corrupt the snapshots,
2362 * because all the tree which are snapshoted will be forced to COW
2363 * the nodes and leaves.
2364 */
2365 ret = btrfs_run_delayed_items(trans);
2366 if (ret)
2367 goto unlock_reloc;
2368
2369 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2370 if (ret)
2371 goto unlock_reloc;
2372
2373 /*
2374 * make sure none of the code above managed to slip in a
2375 * delayed item
2376 */
2377 btrfs_assert_delayed_root_empty(fs_info);
2378
2379 WARN_ON(cur_trans != trans->transaction);
2380
2381 ret = commit_fs_roots(trans);
2382 if (ret)
2383 goto unlock_reloc;
2384
2385 /* commit_fs_roots gets rid of all the tree log roots, it is now
2386 * safe to free the root of tree log roots
2387 */
2388 btrfs_free_log_root_tree(trans, fs_info);
2389
2390 /*
2391 * Since fs roots are all committed, we can get a quite accurate
2392 * new_roots. So let's do quota accounting.
2393 */
2394 ret = btrfs_qgroup_account_extents(trans);
2395 if (ret < 0)
2396 goto unlock_reloc;
2397
2398 ret = commit_cowonly_roots(trans);
2399 if (ret)
2400 goto unlock_reloc;
2401
2402 /*
2403 * The tasks which save the space cache and inode cache may also
2404 * update ->aborted, check it.
2405 */
2406 if (TRANS_ABORTED(cur_trans)) {
2407 ret = cur_trans->aborted;
2408 goto unlock_reloc;
2409 }
2410
2411 cur_trans = fs_info->running_transaction;
2412
2413 btrfs_set_root_node(&fs_info->tree_root->root_item,
2414 fs_info->tree_root->node);
2415 list_add_tail(&fs_info->tree_root->dirty_list,
2416 &cur_trans->switch_commits);
2417
2418 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2419 fs_info->chunk_root->node);
2420 list_add_tail(&fs_info->chunk_root->dirty_list,
2421 &cur_trans->switch_commits);
2422
2423 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2424 btrfs_set_root_node(&fs_info->block_group_root->root_item,
2425 fs_info->block_group_root->node);
2426 list_add_tail(&fs_info->block_group_root->dirty_list,
2427 &cur_trans->switch_commits);
2428 }
2429
2430 switch_commit_roots(trans);
2431
2432 ASSERT(list_empty(&cur_trans->dirty_bgs));
2433 ASSERT(list_empty(&cur_trans->io_bgs));
2434 update_super_roots(fs_info);
2435
2436 btrfs_set_super_log_root(fs_info->super_copy, 0);
2437 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2438 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2439 sizeof(*fs_info->super_copy));
2440
2441 btrfs_commit_device_sizes(cur_trans);
2442
2443 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2444 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2445
2446 btrfs_trans_release_chunk_metadata(trans);
2447
2448 /*
2449 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2450 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2451 * make sure that before we commit our superblock, no other task can
2452 * start a new transaction and commit a log tree before we commit our
2453 * superblock. Anyone trying to commit a log tree locks this mutex before
2454 * writing its superblock.
2455 */
2456 mutex_lock(&fs_info->tree_log_mutex);
2457
2458 spin_lock(&fs_info->trans_lock);
2459 cur_trans->state = TRANS_STATE_UNBLOCKED;
2460 fs_info->running_transaction = NULL;
2461 spin_unlock(&fs_info->trans_lock);
2462 mutex_unlock(&fs_info->reloc_mutex);
2463
2464 wake_up(&fs_info->transaction_wait);
2465 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2466
2467 ret = btrfs_write_and_wait_transaction(trans);
2468 if (ret) {
2469 btrfs_handle_fs_error(fs_info, ret,
2470 "Error while writing out transaction");
2471 mutex_unlock(&fs_info->tree_log_mutex);
2472 goto scrub_continue;
2473 }
2474
2475 /*
2476 * At this point, we should have written all the tree blocks allocated
2477 * in this transaction. So it's now safe to free the redirtyied extent
2478 * buffers.
2479 */
2480 btrfs_free_redirty_list(cur_trans);
2481
2482 ret = write_all_supers(fs_info, 0);
2483 /*
2484 * the super is written, we can safely allow the tree-loggers
2485 * to go about their business
2486 */
2487 mutex_unlock(&fs_info->tree_log_mutex);
2488 if (ret)
2489 goto scrub_continue;
2490
2491 /*
2492 * We needn't acquire the lock here because there is no other task
2493 * which can change it.
2494 */
2495 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2496 wake_up(&cur_trans->commit_wait);
2497 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2498
2499 btrfs_finish_extent_commit(trans);
2500
2501 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2502 btrfs_clear_space_info_full(fs_info);
2503
2504 fs_info->last_trans_committed = cur_trans->transid;
2505 /*
2506 * We needn't acquire the lock here because there is no other task
2507 * which can change it.
2508 */
2509 cur_trans->state = TRANS_STATE_COMPLETED;
2510 wake_up(&cur_trans->commit_wait);
2511 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2512
2513 spin_lock(&fs_info->trans_lock);
2514 list_del_init(&cur_trans->list);
2515 spin_unlock(&fs_info->trans_lock);
2516
2517 btrfs_put_transaction(cur_trans);
2518 btrfs_put_transaction(cur_trans);
2519
2520 if (trans->type & __TRANS_FREEZABLE)
2521 sb_end_intwrite(fs_info->sb);
2522
2523 trace_btrfs_transaction_commit(fs_info);
2524
2525 interval = ktime_get_ns() - start_time;
2526
2527 btrfs_scrub_continue(fs_info);
2528
2529 if (current->journal_info == trans)
2530 current->journal_info = NULL;
2531
2532 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2533
2534 update_commit_stats(fs_info, interval);
2535
2536 return ret;
2537
2538unlock_reloc:
2539 mutex_unlock(&fs_info->reloc_mutex);
2540 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2541scrub_continue:
2542 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2543 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2544 btrfs_scrub_continue(fs_info);
2545cleanup_transaction:
2546 btrfs_trans_release_metadata(trans);
2547 btrfs_cleanup_pending_block_groups(trans);
2548 btrfs_trans_release_chunk_metadata(trans);
2549 trans->block_rsv = NULL;
2550 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2551 if (current->journal_info == trans)
2552 current->journal_info = NULL;
2553 cleanup_transaction(trans, ret);
2554
2555 return ret;
2556
2557lockdep_release:
2558 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2559 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2560 goto cleanup_transaction;
2561
2562lockdep_trans_commit_start_release:
2563 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2564 btrfs_end_transaction(trans);
2565 return ret;
2566}
2567
2568/*
2569 * return < 0 if error
2570 * 0 if there are no more dead_roots at the time of call
2571 * 1 there are more to be processed, call me again
2572 *
2573 * The return value indicates there are certainly more snapshots to delete, but
2574 * if there comes a new one during processing, it may return 0. We don't mind,
2575 * because btrfs_commit_super will poke cleaner thread and it will process it a
2576 * few seconds later.
2577 */
2578int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2579{
2580 struct btrfs_root *root;
2581 int ret;
2582
2583 spin_lock(&fs_info->trans_lock);
2584 if (list_empty(&fs_info->dead_roots)) {
2585 spin_unlock(&fs_info->trans_lock);
2586 return 0;
2587 }
2588 root = list_first_entry(&fs_info->dead_roots,
2589 struct btrfs_root, root_list);
2590 list_del_init(&root->root_list);
2591 spin_unlock(&fs_info->trans_lock);
2592
2593 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2594
2595 btrfs_kill_all_delayed_nodes(root);
2596
2597 if (btrfs_header_backref_rev(root->node) <
2598 BTRFS_MIXED_BACKREF_REV)
2599 ret = btrfs_drop_snapshot(root, 0, 0);
2600 else
2601 ret = btrfs_drop_snapshot(root, 1, 0);
2602
2603 btrfs_put_root(root);
2604 return (ret < 0) ? 0 : 1;
2605}
2606
2607int __init btrfs_transaction_init(void)
2608{
2609 btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
2610 sizeof(struct btrfs_trans_handle), 0,
2611 SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
2612 if (!btrfs_trans_handle_cachep)
2613 return -ENOMEM;
2614 return 0;
2615}
2616
2617void __cold btrfs_transaction_exit(void)
2618{
2619 kmem_cache_destroy(btrfs_trans_handle_cachep);
2620}
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 "misc.h"
14#include "ctree.h"
15#include "disk-io.h"
16#include "transaction.h"
17#include "locking.h"
18#include "tree-log.h"
19#include "volumes.h"
20#include "dev-replace.h"
21#include "qgroup.h"
22#include "block-group.h"
23#include "space-info.h"
24#include "zoned.h"
25
26#define BTRFS_ROOT_TRANS_TAG 0
27
28/*
29 * Transaction states and transitions
30 *
31 * No running transaction (fs tree blocks are not modified)
32 * |
33 * | To next stage:
34 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
35 * V
36 * Transaction N [[TRANS_STATE_RUNNING]]
37 * |
38 * | New trans handles can be attached to transaction N by calling all
39 * | start_transaction() variants.
40 * |
41 * | To next stage:
42 * | Call btrfs_commit_transaction() on any trans handle attached to
43 * | transaction N
44 * V
45 * Transaction N [[TRANS_STATE_COMMIT_START]]
46 * |
47 * | Will wait for previous running transaction to completely finish if there
48 * | is one
49 * |
50 * | Then one of the following happes:
51 * | - Wait for all other trans handle holders to release.
52 * | The btrfs_commit_transaction() caller will do the commit work.
53 * | - Wait for current transaction to be committed by others.
54 * | Other btrfs_commit_transaction() caller will do the commit work.
55 * |
56 * | At this stage, only btrfs_join_transaction*() variants can attach
57 * | to this running transaction.
58 * | All other variants will wait for current one to finish and attach to
59 * | transaction N+1.
60 * |
61 * | To next stage:
62 * | Caller is chosen to commit transaction N, and all other trans handle
63 * | haven been released.
64 * V
65 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
66 * |
67 * | The heavy lifting transaction work is started.
68 * | From running delayed refs (modifying extent tree) to creating pending
69 * | snapshots, running qgroups.
70 * | In short, modify supporting trees to reflect modifications of subvolume
71 * | trees.
72 * |
73 * | At this stage, all start_transaction() calls will wait for this
74 * | transaction to finish and attach to transaction N+1.
75 * |
76 * | To next stage:
77 * | Until all supporting trees are updated.
78 * V
79 * Transaction N [[TRANS_STATE_UNBLOCKED]]
80 * | Transaction N+1
81 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
82 * | need to write them back to disk and update |
83 * | super blocks. |
84 * | |
85 * | At this stage, new transaction is allowed to |
86 * | start. |
87 * | All new start_transaction() calls will be |
88 * | attached to transid N+1. |
89 * | |
90 * | To next stage: |
91 * | Until all tree blocks are super blocks are |
92 * | written to block devices |
93 * V |
94 * Transaction N [[TRANS_STATE_COMPLETED]] V
95 * All tree blocks and super blocks are written. Transaction N+1
96 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
97 * data structures will be cleaned up. | Life goes on
98 */
99static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
100 [TRANS_STATE_RUNNING] = 0U,
101 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
102 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
103 __TRANS_ATTACH |
104 __TRANS_JOIN |
105 __TRANS_JOIN_NOSTART),
106 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
107 __TRANS_ATTACH |
108 __TRANS_JOIN |
109 __TRANS_JOIN_NOLOCK |
110 __TRANS_JOIN_NOSTART),
111 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
112 __TRANS_ATTACH |
113 __TRANS_JOIN |
114 __TRANS_JOIN_NOLOCK |
115 __TRANS_JOIN_NOSTART),
116 [TRANS_STATE_COMPLETED] = (__TRANS_START |
117 __TRANS_ATTACH |
118 __TRANS_JOIN |
119 __TRANS_JOIN_NOLOCK |
120 __TRANS_JOIN_NOSTART),
121};
122
123void btrfs_put_transaction(struct btrfs_transaction *transaction)
124{
125 WARN_ON(refcount_read(&transaction->use_count) == 0);
126 if (refcount_dec_and_test(&transaction->use_count)) {
127 BUG_ON(!list_empty(&transaction->list));
128 WARN_ON(!RB_EMPTY_ROOT(
129 &transaction->delayed_refs.href_root.rb_root));
130 WARN_ON(!RB_EMPTY_ROOT(
131 &transaction->delayed_refs.dirty_extent_root));
132 if (transaction->delayed_refs.pending_csums)
133 btrfs_err(transaction->fs_info,
134 "pending csums is %llu",
135 transaction->delayed_refs.pending_csums);
136 /*
137 * If any block groups are found in ->deleted_bgs then it's
138 * because the transaction was aborted and a commit did not
139 * happen (things failed before writing the new superblock
140 * and calling btrfs_finish_extent_commit()), so we can not
141 * discard the physical locations of the block groups.
142 */
143 while (!list_empty(&transaction->deleted_bgs)) {
144 struct btrfs_block_group *cache;
145
146 cache = list_first_entry(&transaction->deleted_bgs,
147 struct btrfs_block_group,
148 bg_list);
149 list_del_init(&cache->bg_list);
150 btrfs_unfreeze_block_group(cache);
151 btrfs_put_block_group(cache);
152 }
153 WARN_ON(!list_empty(&transaction->dev_update_list));
154 kfree(transaction);
155 }
156}
157
158static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
159{
160 struct btrfs_transaction *cur_trans = trans->transaction;
161 struct btrfs_fs_info *fs_info = trans->fs_info;
162 struct btrfs_root *root, *tmp;
163 struct btrfs_caching_control *caching_ctl, *next;
164
165 down_write(&fs_info->commit_root_sem);
166 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
167 dirty_list) {
168 list_del_init(&root->dirty_list);
169 free_extent_buffer(root->commit_root);
170 root->commit_root = btrfs_root_node(root);
171 extent_io_tree_release(&root->dirty_log_pages);
172 btrfs_qgroup_clean_swapped_blocks(root);
173 }
174
175 /* We can free old roots now. */
176 spin_lock(&cur_trans->dropped_roots_lock);
177 while (!list_empty(&cur_trans->dropped_roots)) {
178 root = list_first_entry(&cur_trans->dropped_roots,
179 struct btrfs_root, root_list);
180 list_del_init(&root->root_list);
181 spin_unlock(&cur_trans->dropped_roots_lock);
182 btrfs_free_log(trans, root);
183 btrfs_drop_and_free_fs_root(fs_info, root);
184 spin_lock(&cur_trans->dropped_roots_lock);
185 }
186 spin_unlock(&cur_trans->dropped_roots_lock);
187
188 /*
189 * We have to update the last_byte_to_unpin under the commit_root_sem,
190 * at the same time we swap out the commit roots.
191 *
192 * This is because we must have a real view of the last spot the caching
193 * kthreads were while caching. Consider the following views of the
194 * extent tree for a block group
195 *
196 * commit root
197 * +----+----+----+----+----+----+----+
198 * |\\\\| |\\\\|\\\\| |\\\\|\\\\|
199 * +----+----+----+----+----+----+----+
200 * 0 1 2 3 4 5 6 7
201 *
202 * new commit root
203 * +----+----+----+----+----+----+----+
204 * | | | |\\\\| | |\\\\|
205 * +----+----+----+----+----+----+----+
206 * 0 1 2 3 4 5 6 7
207 *
208 * If the cache_ctl->progress was at 3, then we are only allowed to
209 * unpin [0,1) and [2,3], because the caching thread has already
210 * processed those extents. We are not allowed to unpin [5,6), because
211 * the caching thread will re-start it's search from 3, and thus find
212 * the hole from [4,6) to add to the free space cache.
213 */
214 spin_lock(&fs_info->block_group_cache_lock);
215 list_for_each_entry_safe(caching_ctl, next,
216 &fs_info->caching_block_groups, list) {
217 struct btrfs_block_group *cache = caching_ctl->block_group;
218
219 if (btrfs_block_group_done(cache)) {
220 cache->last_byte_to_unpin = (u64)-1;
221 list_del_init(&caching_ctl->list);
222 btrfs_put_caching_control(caching_ctl);
223 } else {
224 cache->last_byte_to_unpin = caching_ctl->progress;
225 }
226 }
227 spin_unlock(&fs_info->block_group_cache_lock);
228 up_write(&fs_info->commit_root_sem);
229}
230
231static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
232 unsigned int type)
233{
234 if (type & TRANS_EXTWRITERS)
235 atomic_inc(&trans->num_extwriters);
236}
237
238static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
239 unsigned int type)
240{
241 if (type & TRANS_EXTWRITERS)
242 atomic_dec(&trans->num_extwriters);
243}
244
245static inline void extwriter_counter_init(struct btrfs_transaction *trans,
246 unsigned int type)
247{
248 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
249}
250
251static inline int extwriter_counter_read(struct btrfs_transaction *trans)
252{
253 return atomic_read(&trans->num_extwriters);
254}
255
256/*
257 * To be called after doing the chunk btree updates right after allocating a new
258 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
259 * chunk after all chunk btree updates and after finishing the second phase of
260 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
261 * group had its chunk item insertion delayed to the second phase.
262 */
263void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
264{
265 struct btrfs_fs_info *fs_info = trans->fs_info;
266
267 if (!trans->chunk_bytes_reserved)
268 return;
269
270 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
271 trans->chunk_bytes_reserved, NULL);
272 trans->chunk_bytes_reserved = 0;
273}
274
275/*
276 * either allocate a new transaction or hop into the existing one
277 */
278static noinline int join_transaction(struct btrfs_fs_info *fs_info,
279 unsigned int type)
280{
281 struct btrfs_transaction *cur_trans;
282
283 spin_lock(&fs_info->trans_lock);
284loop:
285 /* The file system has been taken offline. No new transactions. */
286 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
287 spin_unlock(&fs_info->trans_lock);
288 return -EROFS;
289 }
290
291 cur_trans = fs_info->running_transaction;
292 if (cur_trans) {
293 if (TRANS_ABORTED(cur_trans)) {
294 spin_unlock(&fs_info->trans_lock);
295 return cur_trans->aborted;
296 }
297 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
298 spin_unlock(&fs_info->trans_lock);
299 return -EBUSY;
300 }
301 refcount_inc(&cur_trans->use_count);
302 atomic_inc(&cur_trans->num_writers);
303 extwriter_counter_inc(cur_trans, type);
304 spin_unlock(&fs_info->trans_lock);
305 return 0;
306 }
307 spin_unlock(&fs_info->trans_lock);
308
309 /*
310 * If we are ATTACH, we just want to catch the current transaction,
311 * and commit it. If there is no transaction, just return ENOENT.
312 */
313 if (type == TRANS_ATTACH)
314 return -ENOENT;
315
316 /*
317 * JOIN_NOLOCK only happens during the transaction commit, so
318 * it is impossible that ->running_transaction is NULL
319 */
320 BUG_ON(type == TRANS_JOIN_NOLOCK);
321
322 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
323 if (!cur_trans)
324 return -ENOMEM;
325
326 spin_lock(&fs_info->trans_lock);
327 if (fs_info->running_transaction) {
328 /*
329 * someone started a transaction after we unlocked. Make sure
330 * to redo the checks above
331 */
332 kfree(cur_trans);
333 goto loop;
334 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
335 spin_unlock(&fs_info->trans_lock);
336 kfree(cur_trans);
337 return -EROFS;
338 }
339
340 cur_trans->fs_info = fs_info;
341 atomic_set(&cur_trans->pending_ordered, 0);
342 init_waitqueue_head(&cur_trans->pending_wait);
343 atomic_set(&cur_trans->num_writers, 1);
344 extwriter_counter_init(cur_trans, type);
345 init_waitqueue_head(&cur_trans->writer_wait);
346 init_waitqueue_head(&cur_trans->commit_wait);
347 cur_trans->state = TRANS_STATE_RUNNING;
348 /*
349 * One for this trans handle, one so it will live on until we
350 * commit the transaction.
351 */
352 refcount_set(&cur_trans->use_count, 2);
353 cur_trans->flags = 0;
354 cur_trans->start_time = ktime_get_seconds();
355
356 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
357
358 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
359 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
360 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
361
362 /*
363 * although the tree mod log is per file system and not per transaction,
364 * the log must never go across transaction boundaries.
365 */
366 smp_mb();
367 if (!list_empty(&fs_info->tree_mod_seq_list))
368 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
369 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
370 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
371 atomic64_set(&fs_info->tree_mod_seq, 0);
372
373 spin_lock_init(&cur_trans->delayed_refs.lock);
374
375 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
376 INIT_LIST_HEAD(&cur_trans->dev_update_list);
377 INIT_LIST_HEAD(&cur_trans->switch_commits);
378 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
379 INIT_LIST_HEAD(&cur_trans->io_bgs);
380 INIT_LIST_HEAD(&cur_trans->dropped_roots);
381 mutex_init(&cur_trans->cache_write_mutex);
382 spin_lock_init(&cur_trans->dirty_bgs_lock);
383 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
384 spin_lock_init(&cur_trans->dropped_roots_lock);
385 INIT_LIST_HEAD(&cur_trans->releasing_ebs);
386 spin_lock_init(&cur_trans->releasing_ebs_lock);
387 list_add_tail(&cur_trans->list, &fs_info->trans_list);
388 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
389 IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
390 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
391 IO_TREE_FS_PINNED_EXTENTS, NULL);
392 fs_info->generation++;
393 cur_trans->transid = fs_info->generation;
394 fs_info->running_transaction = cur_trans;
395 cur_trans->aborted = 0;
396 spin_unlock(&fs_info->trans_lock);
397
398 return 0;
399}
400
401/*
402 * This does all the record keeping required to make sure that a shareable root
403 * is properly recorded in a given transaction. This is required to make sure
404 * the old root from before we joined the transaction is deleted when the
405 * transaction commits.
406 */
407static int record_root_in_trans(struct btrfs_trans_handle *trans,
408 struct btrfs_root *root,
409 int force)
410{
411 struct btrfs_fs_info *fs_info = root->fs_info;
412 int ret = 0;
413
414 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
415 root->last_trans < trans->transid) || force) {
416 WARN_ON(root == fs_info->extent_root);
417 WARN_ON(!force && root->commit_root != root->node);
418
419 /*
420 * see below for IN_TRANS_SETUP usage rules
421 * we have the reloc mutex held now, so there
422 * is only one writer in this function
423 */
424 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
425
426 /* make sure readers find IN_TRANS_SETUP before
427 * they find our root->last_trans update
428 */
429 smp_wmb();
430
431 spin_lock(&fs_info->fs_roots_radix_lock);
432 if (root->last_trans == trans->transid && !force) {
433 spin_unlock(&fs_info->fs_roots_radix_lock);
434 return 0;
435 }
436 radix_tree_tag_set(&fs_info->fs_roots_radix,
437 (unsigned long)root->root_key.objectid,
438 BTRFS_ROOT_TRANS_TAG);
439 spin_unlock(&fs_info->fs_roots_radix_lock);
440 root->last_trans = trans->transid;
441
442 /* this is pretty tricky. We don't want to
443 * take the relocation lock in btrfs_record_root_in_trans
444 * unless we're really doing the first setup for this root in
445 * this transaction.
446 *
447 * Normally we'd use root->last_trans as a flag to decide
448 * if we want to take the expensive mutex.
449 *
450 * But, we have to set root->last_trans before we
451 * init the relocation root, otherwise, we trip over warnings
452 * in ctree.c. The solution used here is to flag ourselves
453 * with root IN_TRANS_SETUP. When this is 1, we're still
454 * fixing up the reloc trees and everyone must wait.
455 *
456 * When this is zero, they can trust root->last_trans and fly
457 * through btrfs_record_root_in_trans without having to take the
458 * lock. smp_wmb() makes sure that all the writes above are
459 * done before we pop in the zero below
460 */
461 ret = btrfs_init_reloc_root(trans, root);
462 smp_mb__before_atomic();
463 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
464 }
465 return ret;
466}
467
468
469void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
470 struct btrfs_root *root)
471{
472 struct btrfs_fs_info *fs_info = root->fs_info;
473 struct btrfs_transaction *cur_trans = trans->transaction;
474
475 /* Add ourselves to the transaction dropped list */
476 spin_lock(&cur_trans->dropped_roots_lock);
477 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
478 spin_unlock(&cur_trans->dropped_roots_lock);
479
480 /* Make sure we don't try to update the root at commit time */
481 spin_lock(&fs_info->fs_roots_radix_lock);
482 radix_tree_tag_clear(&fs_info->fs_roots_radix,
483 (unsigned long)root->root_key.objectid,
484 BTRFS_ROOT_TRANS_TAG);
485 spin_unlock(&fs_info->fs_roots_radix_lock);
486}
487
488int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
489 struct btrfs_root *root)
490{
491 struct btrfs_fs_info *fs_info = root->fs_info;
492 int ret;
493
494 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
495 return 0;
496
497 /*
498 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
499 * and barriers
500 */
501 smp_rmb();
502 if (root->last_trans == trans->transid &&
503 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
504 return 0;
505
506 mutex_lock(&fs_info->reloc_mutex);
507 ret = record_root_in_trans(trans, root, 0);
508 mutex_unlock(&fs_info->reloc_mutex);
509
510 return ret;
511}
512
513static inline int is_transaction_blocked(struct btrfs_transaction *trans)
514{
515 return (trans->state >= TRANS_STATE_COMMIT_START &&
516 trans->state < TRANS_STATE_UNBLOCKED &&
517 !TRANS_ABORTED(trans));
518}
519
520/* wait for commit against the current transaction to become unblocked
521 * when this is done, it is safe to start a new transaction, but the current
522 * transaction might not be fully on disk.
523 */
524static void wait_current_trans(struct btrfs_fs_info *fs_info)
525{
526 struct btrfs_transaction *cur_trans;
527
528 spin_lock(&fs_info->trans_lock);
529 cur_trans = fs_info->running_transaction;
530 if (cur_trans && is_transaction_blocked(cur_trans)) {
531 refcount_inc(&cur_trans->use_count);
532 spin_unlock(&fs_info->trans_lock);
533
534 wait_event(fs_info->transaction_wait,
535 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
536 TRANS_ABORTED(cur_trans));
537 btrfs_put_transaction(cur_trans);
538 } else {
539 spin_unlock(&fs_info->trans_lock);
540 }
541}
542
543static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
544{
545 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
546 return 0;
547
548 if (type == TRANS_START)
549 return 1;
550
551 return 0;
552}
553
554static inline bool need_reserve_reloc_root(struct btrfs_root *root)
555{
556 struct btrfs_fs_info *fs_info = root->fs_info;
557
558 if (!fs_info->reloc_ctl ||
559 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
560 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
561 root->reloc_root)
562 return false;
563
564 return true;
565}
566
567static struct btrfs_trans_handle *
568start_transaction(struct btrfs_root *root, unsigned int num_items,
569 unsigned int type, enum btrfs_reserve_flush_enum flush,
570 bool enforce_qgroups)
571{
572 struct btrfs_fs_info *fs_info = root->fs_info;
573 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
574 struct btrfs_trans_handle *h;
575 struct btrfs_transaction *cur_trans;
576 u64 num_bytes = 0;
577 u64 qgroup_reserved = 0;
578 bool reloc_reserved = false;
579 bool do_chunk_alloc = false;
580 int ret;
581
582 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
583 return ERR_PTR(-EROFS);
584
585 if (current->journal_info) {
586 WARN_ON(type & TRANS_EXTWRITERS);
587 h = current->journal_info;
588 refcount_inc(&h->use_count);
589 WARN_ON(refcount_read(&h->use_count) > 2);
590 h->orig_rsv = h->block_rsv;
591 h->block_rsv = NULL;
592 goto got_it;
593 }
594
595 /*
596 * Do the reservation before we join the transaction so we can do all
597 * the appropriate flushing if need be.
598 */
599 if (num_items && root != fs_info->chunk_root) {
600 struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
601 u64 delayed_refs_bytes = 0;
602
603 qgroup_reserved = num_items * fs_info->nodesize;
604 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
605 enforce_qgroups);
606 if (ret)
607 return ERR_PTR(ret);
608
609 /*
610 * We want to reserve all the bytes we may need all at once, so
611 * we only do 1 enospc flushing cycle per transaction start. We
612 * accomplish this by simply assuming we'll do 2 x num_items
613 * worth of delayed refs updates in this trans handle, and
614 * refill that amount for whatever is missing in the reserve.
615 */
616 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
617 if (flush == BTRFS_RESERVE_FLUSH_ALL &&
618 delayed_refs_rsv->full == 0) {
619 delayed_refs_bytes = num_bytes;
620 num_bytes <<= 1;
621 }
622
623 /*
624 * Do the reservation for the relocation root creation
625 */
626 if (need_reserve_reloc_root(root)) {
627 num_bytes += fs_info->nodesize;
628 reloc_reserved = true;
629 }
630
631 ret = btrfs_block_rsv_add(root, rsv, num_bytes, flush);
632 if (ret)
633 goto reserve_fail;
634 if (delayed_refs_bytes) {
635 btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
636 delayed_refs_bytes);
637 num_bytes -= delayed_refs_bytes;
638 }
639
640 if (rsv->space_info->force_alloc)
641 do_chunk_alloc = true;
642 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
643 !delayed_refs_rsv->full) {
644 /*
645 * Some people call with btrfs_start_transaction(root, 0)
646 * because they can be throttled, but have some other mechanism
647 * for reserving space. We still want these guys to refill the
648 * delayed block_rsv so just add 1 items worth of reservation
649 * here.
650 */
651 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
652 if (ret)
653 goto reserve_fail;
654 }
655again:
656 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
657 if (!h) {
658 ret = -ENOMEM;
659 goto alloc_fail;
660 }
661
662 /*
663 * If we are JOIN_NOLOCK we're already committing a transaction and
664 * waiting on this guy, so we don't need to do the sb_start_intwrite
665 * because we're already holding a ref. We need this because we could
666 * have raced in and did an fsync() on a file which can kick a commit
667 * and then we deadlock with somebody doing a freeze.
668 *
669 * If we are ATTACH, it means we just want to catch the current
670 * transaction and commit it, so we needn't do sb_start_intwrite().
671 */
672 if (type & __TRANS_FREEZABLE)
673 sb_start_intwrite(fs_info->sb);
674
675 if (may_wait_transaction(fs_info, type))
676 wait_current_trans(fs_info);
677
678 do {
679 ret = join_transaction(fs_info, type);
680 if (ret == -EBUSY) {
681 wait_current_trans(fs_info);
682 if (unlikely(type == TRANS_ATTACH ||
683 type == TRANS_JOIN_NOSTART))
684 ret = -ENOENT;
685 }
686 } while (ret == -EBUSY);
687
688 if (ret < 0)
689 goto join_fail;
690
691 cur_trans = fs_info->running_transaction;
692
693 h->transid = cur_trans->transid;
694 h->transaction = cur_trans;
695 h->root = root;
696 refcount_set(&h->use_count, 1);
697 h->fs_info = root->fs_info;
698
699 h->type = type;
700 INIT_LIST_HEAD(&h->new_bgs);
701
702 smp_mb();
703 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
704 may_wait_transaction(fs_info, type)) {
705 current->journal_info = h;
706 btrfs_commit_transaction(h);
707 goto again;
708 }
709
710 if (num_bytes) {
711 trace_btrfs_space_reservation(fs_info, "transaction",
712 h->transid, num_bytes, 1);
713 h->block_rsv = &fs_info->trans_block_rsv;
714 h->bytes_reserved = num_bytes;
715 h->reloc_reserved = reloc_reserved;
716 }
717
718got_it:
719 if (!current->journal_info)
720 current->journal_info = h;
721
722 /*
723 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
724 * ALLOC_FORCE the first run through, and then we won't allocate for
725 * anybody else who races in later. We don't care about the return
726 * value here.
727 */
728 if (do_chunk_alloc && num_bytes) {
729 u64 flags = h->block_rsv->space_info->flags;
730
731 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
732 CHUNK_ALLOC_NO_FORCE);
733 }
734
735 /*
736 * btrfs_record_root_in_trans() needs to alloc new extents, and may
737 * call btrfs_join_transaction() while we're also starting a
738 * transaction.
739 *
740 * Thus it need to be called after current->journal_info initialized,
741 * or we can deadlock.
742 */
743 ret = btrfs_record_root_in_trans(h, root);
744 if (ret) {
745 /*
746 * The transaction handle is fully initialized and linked with
747 * other structures so it needs to be ended in case of errors,
748 * not just freed.
749 */
750 btrfs_end_transaction(h);
751 return ERR_PTR(ret);
752 }
753
754 return h;
755
756join_fail:
757 if (type & __TRANS_FREEZABLE)
758 sb_end_intwrite(fs_info->sb);
759 kmem_cache_free(btrfs_trans_handle_cachep, h);
760alloc_fail:
761 if (num_bytes)
762 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
763 num_bytes, NULL);
764reserve_fail:
765 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
766 return ERR_PTR(ret);
767}
768
769struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
770 unsigned int num_items)
771{
772 return start_transaction(root, num_items, TRANS_START,
773 BTRFS_RESERVE_FLUSH_ALL, true);
774}
775
776struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
777 struct btrfs_root *root,
778 unsigned int num_items)
779{
780 return start_transaction(root, num_items, TRANS_START,
781 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
782}
783
784struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
785{
786 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
787 true);
788}
789
790struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
791{
792 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
793 BTRFS_RESERVE_NO_FLUSH, true);
794}
795
796/*
797 * Similar to regular join but it never starts a transaction when none is
798 * running or after waiting for the current one to finish.
799 */
800struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
801{
802 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
803 BTRFS_RESERVE_NO_FLUSH, true);
804}
805
806/*
807 * btrfs_attach_transaction() - catch the running transaction
808 *
809 * It is used when we want to commit the current the transaction, but
810 * don't want to start a new one.
811 *
812 * Note: If this function return -ENOENT, it just means there is no
813 * running transaction. But it is possible that the inactive transaction
814 * is still in the memory, not fully on disk. If you hope there is no
815 * inactive transaction in the fs when -ENOENT is returned, you should
816 * invoke
817 * btrfs_attach_transaction_barrier()
818 */
819struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
820{
821 return start_transaction(root, 0, TRANS_ATTACH,
822 BTRFS_RESERVE_NO_FLUSH, true);
823}
824
825/*
826 * btrfs_attach_transaction_barrier() - catch the running transaction
827 *
828 * It is similar to the above function, the difference is this one
829 * will wait for all the inactive transactions until they fully
830 * complete.
831 */
832struct btrfs_trans_handle *
833btrfs_attach_transaction_barrier(struct btrfs_root *root)
834{
835 struct btrfs_trans_handle *trans;
836
837 trans = start_transaction(root, 0, TRANS_ATTACH,
838 BTRFS_RESERVE_NO_FLUSH, true);
839 if (trans == ERR_PTR(-ENOENT))
840 btrfs_wait_for_commit(root->fs_info, 0);
841
842 return trans;
843}
844
845/* Wait for a transaction commit to reach at least the given state. */
846static noinline void wait_for_commit(struct btrfs_transaction *commit,
847 const enum btrfs_trans_state min_state)
848{
849 wait_event(commit->commit_wait, commit->state >= min_state);
850}
851
852int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
853{
854 struct btrfs_transaction *cur_trans = NULL, *t;
855 int ret = 0;
856
857 if (transid) {
858 if (transid <= fs_info->last_trans_committed)
859 goto out;
860
861 /* find specified transaction */
862 spin_lock(&fs_info->trans_lock);
863 list_for_each_entry(t, &fs_info->trans_list, list) {
864 if (t->transid == transid) {
865 cur_trans = t;
866 refcount_inc(&cur_trans->use_count);
867 ret = 0;
868 break;
869 }
870 if (t->transid > transid) {
871 ret = 0;
872 break;
873 }
874 }
875 spin_unlock(&fs_info->trans_lock);
876
877 /*
878 * The specified transaction doesn't exist, or we
879 * raced with btrfs_commit_transaction
880 */
881 if (!cur_trans) {
882 if (transid > fs_info->last_trans_committed)
883 ret = -EINVAL;
884 goto out;
885 }
886 } else {
887 /* find newest transaction that is committing | committed */
888 spin_lock(&fs_info->trans_lock);
889 list_for_each_entry_reverse(t, &fs_info->trans_list,
890 list) {
891 if (t->state >= TRANS_STATE_COMMIT_START) {
892 if (t->state == TRANS_STATE_COMPLETED)
893 break;
894 cur_trans = t;
895 refcount_inc(&cur_trans->use_count);
896 break;
897 }
898 }
899 spin_unlock(&fs_info->trans_lock);
900 if (!cur_trans)
901 goto out; /* nothing committing|committed */
902 }
903
904 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
905 btrfs_put_transaction(cur_trans);
906out:
907 return ret;
908}
909
910void btrfs_throttle(struct btrfs_fs_info *fs_info)
911{
912 wait_current_trans(fs_info);
913}
914
915static bool should_end_transaction(struct btrfs_trans_handle *trans)
916{
917 struct btrfs_fs_info *fs_info = trans->fs_info;
918
919 if (btrfs_check_space_for_delayed_refs(fs_info))
920 return true;
921
922 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
923}
924
925bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
926{
927 struct btrfs_transaction *cur_trans = trans->transaction;
928
929 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
930 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
931 return true;
932
933 return should_end_transaction(trans);
934}
935
936static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
937
938{
939 struct btrfs_fs_info *fs_info = trans->fs_info;
940
941 if (!trans->block_rsv) {
942 ASSERT(!trans->bytes_reserved);
943 return;
944 }
945
946 if (!trans->bytes_reserved)
947 return;
948
949 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
950 trace_btrfs_space_reservation(fs_info, "transaction",
951 trans->transid, trans->bytes_reserved, 0);
952 btrfs_block_rsv_release(fs_info, trans->block_rsv,
953 trans->bytes_reserved, NULL);
954 trans->bytes_reserved = 0;
955}
956
957static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
958 int throttle)
959{
960 struct btrfs_fs_info *info = trans->fs_info;
961 struct btrfs_transaction *cur_trans = trans->transaction;
962 int err = 0;
963
964 if (refcount_read(&trans->use_count) > 1) {
965 refcount_dec(&trans->use_count);
966 trans->block_rsv = trans->orig_rsv;
967 return 0;
968 }
969
970 btrfs_trans_release_metadata(trans);
971 trans->block_rsv = NULL;
972
973 btrfs_create_pending_block_groups(trans);
974
975 btrfs_trans_release_chunk_metadata(trans);
976
977 if (trans->type & __TRANS_FREEZABLE)
978 sb_end_intwrite(info->sb);
979
980 WARN_ON(cur_trans != info->running_transaction);
981 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
982 atomic_dec(&cur_trans->num_writers);
983 extwriter_counter_dec(cur_trans, trans->type);
984
985 cond_wake_up(&cur_trans->writer_wait);
986 btrfs_put_transaction(cur_trans);
987
988 if (current->journal_info == trans)
989 current->journal_info = NULL;
990
991 if (throttle)
992 btrfs_run_delayed_iputs(info);
993
994 if (TRANS_ABORTED(trans) ||
995 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
996 wake_up_process(info->transaction_kthread);
997 if (TRANS_ABORTED(trans))
998 err = trans->aborted;
999 else
1000 err = -EROFS;
1001 }
1002
1003 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1004 return err;
1005}
1006
1007int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1008{
1009 return __btrfs_end_transaction(trans, 0);
1010}
1011
1012int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1013{
1014 return __btrfs_end_transaction(trans, 1);
1015}
1016
1017/*
1018 * when btree blocks are allocated, they have some corresponding bits set for
1019 * them in one of two extent_io trees. This is used to make sure all of
1020 * those extents are sent to disk but does not wait on them
1021 */
1022int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1023 struct extent_io_tree *dirty_pages, int mark)
1024{
1025 int err = 0;
1026 int werr = 0;
1027 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1028 struct extent_state *cached_state = NULL;
1029 u64 start = 0;
1030 u64 end;
1031
1032 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1033 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1034 mark, &cached_state)) {
1035 bool wait_writeback = false;
1036
1037 err = convert_extent_bit(dirty_pages, start, end,
1038 EXTENT_NEED_WAIT,
1039 mark, &cached_state);
1040 /*
1041 * convert_extent_bit can return -ENOMEM, which is most of the
1042 * time a temporary error. So when it happens, ignore the error
1043 * and wait for writeback of this range to finish - because we
1044 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1045 * to __btrfs_wait_marked_extents() would not know that
1046 * writeback for this range started and therefore wouldn't
1047 * wait for it to finish - we don't want to commit a
1048 * superblock that points to btree nodes/leafs for which
1049 * writeback hasn't finished yet (and without errors).
1050 * We cleanup any entries left in the io tree when committing
1051 * the transaction (through extent_io_tree_release()).
1052 */
1053 if (err == -ENOMEM) {
1054 err = 0;
1055 wait_writeback = true;
1056 }
1057 if (!err)
1058 err = filemap_fdatawrite_range(mapping, start, end);
1059 if (err)
1060 werr = err;
1061 else if (wait_writeback)
1062 werr = filemap_fdatawait_range(mapping, start, end);
1063 free_extent_state(cached_state);
1064 cached_state = NULL;
1065 cond_resched();
1066 start = end + 1;
1067 }
1068 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1069 return werr;
1070}
1071
1072/*
1073 * when btree blocks are allocated, they have some corresponding bits set for
1074 * them in one of two extent_io trees. This is used to make sure all of
1075 * those extents are on disk for transaction or log commit. We wait
1076 * on all the pages and clear them from the dirty pages state tree
1077 */
1078static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1079 struct extent_io_tree *dirty_pages)
1080{
1081 int err = 0;
1082 int werr = 0;
1083 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1084 struct extent_state *cached_state = NULL;
1085 u64 start = 0;
1086 u64 end;
1087
1088 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1089 EXTENT_NEED_WAIT, &cached_state)) {
1090 /*
1091 * Ignore -ENOMEM errors returned by clear_extent_bit().
1092 * When committing the transaction, we'll remove any entries
1093 * left in the io tree. For a log commit, we don't remove them
1094 * after committing the log because the tree can be accessed
1095 * concurrently - we do it only at transaction commit time when
1096 * it's safe to do it (through extent_io_tree_release()).
1097 */
1098 err = clear_extent_bit(dirty_pages, start, end,
1099 EXTENT_NEED_WAIT, 0, 0, &cached_state);
1100 if (err == -ENOMEM)
1101 err = 0;
1102 if (!err)
1103 err = filemap_fdatawait_range(mapping, start, end);
1104 if (err)
1105 werr = err;
1106 free_extent_state(cached_state);
1107 cached_state = NULL;
1108 cond_resched();
1109 start = end + 1;
1110 }
1111 if (err)
1112 werr = err;
1113 return werr;
1114}
1115
1116static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1117 struct extent_io_tree *dirty_pages)
1118{
1119 bool errors = false;
1120 int err;
1121
1122 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1123 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1124 errors = true;
1125
1126 if (errors && !err)
1127 err = -EIO;
1128 return err;
1129}
1130
1131int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1132{
1133 struct btrfs_fs_info *fs_info = log_root->fs_info;
1134 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1135 bool errors = false;
1136 int err;
1137
1138 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1139
1140 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1141 if ((mark & EXTENT_DIRTY) &&
1142 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1143 errors = true;
1144
1145 if ((mark & EXTENT_NEW) &&
1146 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1147 errors = true;
1148
1149 if (errors && !err)
1150 err = -EIO;
1151 return err;
1152}
1153
1154/*
1155 * When btree blocks are allocated the corresponding extents are marked dirty.
1156 * This function ensures such extents are persisted on disk for transaction or
1157 * log commit.
1158 *
1159 * @trans: transaction whose dirty pages we'd like to write
1160 */
1161static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1162{
1163 int ret;
1164 int ret2;
1165 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1166 struct btrfs_fs_info *fs_info = trans->fs_info;
1167 struct blk_plug plug;
1168
1169 blk_start_plug(&plug);
1170 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1171 blk_finish_plug(&plug);
1172 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1173
1174 extent_io_tree_release(&trans->transaction->dirty_pages);
1175
1176 if (ret)
1177 return ret;
1178 else if (ret2)
1179 return ret2;
1180 else
1181 return 0;
1182}
1183
1184/*
1185 * this is used to update the root pointer in the tree of tree roots.
1186 *
1187 * But, in the case of the extent allocation tree, updating the root
1188 * pointer may allocate blocks which may change the root of the extent
1189 * allocation tree.
1190 *
1191 * So, this loops and repeats and makes sure the cowonly root didn't
1192 * change while the root pointer was being updated in the metadata.
1193 */
1194static int update_cowonly_root(struct btrfs_trans_handle *trans,
1195 struct btrfs_root *root)
1196{
1197 int ret;
1198 u64 old_root_bytenr;
1199 u64 old_root_used;
1200 struct btrfs_fs_info *fs_info = root->fs_info;
1201 struct btrfs_root *tree_root = fs_info->tree_root;
1202
1203 old_root_used = btrfs_root_used(&root->root_item);
1204
1205 while (1) {
1206 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1207 if (old_root_bytenr == root->node->start &&
1208 old_root_used == btrfs_root_used(&root->root_item))
1209 break;
1210
1211 btrfs_set_root_node(&root->root_item, root->node);
1212 ret = btrfs_update_root(trans, tree_root,
1213 &root->root_key,
1214 &root->root_item);
1215 if (ret)
1216 return ret;
1217
1218 old_root_used = btrfs_root_used(&root->root_item);
1219 }
1220
1221 return 0;
1222}
1223
1224/*
1225 * update all the cowonly tree roots on disk
1226 *
1227 * The error handling in this function may not be obvious. Any of the
1228 * failures will cause the file system to go offline. We still need
1229 * to clean up the delayed refs.
1230 */
1231static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1232{
1233 struct btrfs_fs_info *fs_info = trans->fs_info;
1234 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1235 struct list_head *io_bgs = &trans->transaction->io_bgs;
1236 struct list_head *next;
1237 struct extent_buffer *eb;
1238 int ret;
1239
1240 eb = btrfs_lock_root_node(fs_info->tree_root);
1241 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1242 0, &eb, BTRFS_NESTING_COW);
1243 btrfs_tree_unlock(eb);
1244 free_extent_buffer(eb);
1245
1246 if (ret)
1247 return ret;
1248
1249 ret = btrfs_run_dev_stats(trans);
1250 if (ret)
1251 return ret;
1252 ret = btrfs_run_dev_replace(trans);
1253 if (ret)
1254 return ret;
1255 ret = btrfs_run_qgroups(trans);
1256 if (ret)
1257 return ret;
1258
1259 ret = btrfs_setup_space_cache(trans);
1260 if (ret)
1261 return ret;
1262
1263again:
1264 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1265 struct btrfs_root *root;
1266 next = fs_info->dirty_cowonly_roots.next;
1267 list_del_init(next);
1268 root = list_entry(next, struct btrfs_root, dirty_list);
1269 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1270
1271 if (root != fs_info->extent_root)
1272 list_add_tail(&root->dirty_list,
1273 &trans->transaction->switch_commits);
1274 ret = update_cowonly_root(trans, root);
1275 if (ret)
1276 return ret;
1277 }
1278
1279 /* Now flush any delayed refs generated by updating all of the roots */
1280 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1281 if (ret)
1282 return ret;
1283
1284 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1285 ret = btrfs_write_dirty_block_groups(trans);
1286 if (ret)
1287 return ret;
1288
1289 /*
1290 * We're writing the dirty block groups, which could generate
1291 * delayed refs, which could generate more dirty block groups,
1292 * so we want to keep this flushing in this loop to make sure
1293 * everything gets run.
1294 */
1295 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1296 if (ret)
1297 return ret;
1298 }
1299
1300 if (!list_empty(&fs_info->dirty_cowonly_roots))
1301 goto again;
1302
1303 list_add_tail(&fs_info->extent_root->dirty_list,
1304 &trans->transaction->switch_commits);
1305
1306 /* Update dev-replace pointer once everything is committed */
1307 fs_info->dev_replace.committed_cursor_left =
1308 fs_info->dev_replace.cursor_left_last_write_of_item;
1309
1310 return 0;
1311}
1312
1313/*
1314 * dead roots are old snapshots that need to be deleted. This allocates
1315 * a dirty root struct and adds it into the list of dead roots that need to
1316 * be deleted
1317 */
1318void btrfs_add_dead_root(struct btrfs_root *root)
1319{
1320 struct btrfs_fs_info *fs_info = root->fs_info;
1321
1322 spin_lock(&fs_info->trans_lock);
1323 if (list_empty(&root->root_list)) {
1324 btrfs_grab_root(root);
1325 list_add_tail(&root->root_list, &fs_info->dead_roots);
1326 }
1327 spin_unlock(&fs_info->trans_lock);
1328}
1329
1330/*
1331 * update all the cowonly tree roots on disk
1332 */
1333static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1334{
1335 struct btrfs_fs_info *fs_info = trans->fs_info;
1336 struct btrfs_root *gang[8];
1337 int i;
1338 int ret;
1339
1340 spin_lock(&fs_info->fs_roots_radix_lock);
1341 while (1) {
1342 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1343 (void **)gang, 0,
1344 ARRAY_SIZE(gang),
1345 BTRFS_ROOT_TRANS_TAG);
1346 if (ret == 0)
1347 break;
1348 for (i = 0; i < ret; i++) {
1349 struct btrfs_root *root = gang[i];
1350 int ret2;
1351
1352 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1353 (unsigned long)root->root_key.objectid,
1354 BTRFS_ROOT_TRANS_TAG);
1355 spin_unlock(&fs_info->fs_roots_radix_lock);
1356
1357 btrfs_free_log(trans, root);
1358 ret2 = btrfs_update_reloc_root(trans, root);
1359 if (ret2)
1360 return ret2;
1361
1362 /* see comments in should_cow_block() */
1363 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1364 smp_mb__after_atomic();
1365
1366 if (root->commit_root != root->node) {
1367 list_add_tail(&root->dirty_list,
1368 &trans->transaction->switch_commits);
1369 btrfs_set_root_node(&root->root_item,
1370 root->node);
1371 }
1372
1373 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1374 &root->root_key,
1375 &root->root_item);
1376 if (ret2)
1377 return ret2;
1378 spin_lock(&fs_info->fs_roots_radix_lock);
1379 btrfs_qgroup_free_meta_all_pertrans(root);
1380 }
1381 }
1382 spin_unlock(&fs_info->fs_roots_radix_lock);
1383 return 0;
1384}
1385
1386/*
1387 * defrag a given btree.
1388 * Every leaf in the btree is read and defragged.
1389 */
1390int btrfs_defrag_root(struct btrfs_root *root)
1391{
1392 struct btrfs_fs_info *info = root->fs_info;
1393 struct btrfs_trans_handle *trans;
1394 int ret;
1395
1396 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1397 return 0;
1398
1399 while (1) {
1400 trans = btrfs_start_transaction(root, 0);
1401 if (IS_ERR(trans)) {
1402 ret = PTR_ERR(trans);
1403 break;
1404 }
1405
1406 ret = btrfs_defrag_leaves(trans, root);
1407
1408 btrfs_end_transaction(trans);
1409 btrfs_btree_balance_dirty(info);
1410 cond_resched();
1411
1412 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1413 break;
1414
1415 if (btrfs_defrag_cancelled(info)) {
1416 btrfs_debug(info, "defrag_root cancelled");
1417 ret = -EAGAIN;
1418 break;
1419 }
1420 }
1421 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1422 return ret;
1423}
1424
1425/*
1426 * Do all special snapshot related qgroup dirty hack.
1427 *
1428 * Will do all needed qgroup inherit and dirty hack like switch commit
1429 * roots inside one transaction and write all btree into disk, to make
1430 * qgroup works.
1431 */
1432static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1433 struct btrfs_root *src,
1434 struct btrfs_root *parent,
1435 struct btrfs_qgroup_inherit *inherit,
1436 u64 dst_objectid)
1437{
1438 struct btrfs_fs_info *fs_info = src->fs_info;
1439 int ret;
1440
1441 /*
1442 * Save some performance in the case that qgroups are not
1443 * enabled. If this check races with the ioctl, rescan will
1444 * kick in anyway.
1445 */
1446 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1447 return 0;
1448
1449 /*
1450 * Ensure dirty @src will be committed. Or, after coming
1451 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1452 * recorded root will never be updated again, causing an outdated root
1453 * item.
1454 */
1455 ret = record_root_in_trans(trans, src, 1);
1456 if (ret)
1457 return ret;
1458
1459 /*
1460 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1461 * src root, so we must run the delayed refs here.
1462 *
1463 * However this isn't particularly fool proof, because there's no
1464 * synchronization keeping us from changing the tree after this point
1465 * before we do the qgroup_inherit, or even from making changes while
1466 * we're doing the qgroup_inherit. But that's a problem for the future,
1467 * for now flush the delayed refs to narrow the race window where the
1468 * qgroup counters could end up wrong.
1469 */
1470 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1471 if (ret) {
1472 btrfs_abort_transaction(trans, ret);
1473 return ret;
1474 }
1475
1476 /*
1477 * We are going to commit transaction, see btrfs_commit_transaction()
1478 * comment for reason locking tree_log_mutex
1479 */
1480 mutex_lock(&fs_info->tree_log_mutex);
1481
1482 ret = commit_fs_roots(trans);
1483 if (ret)
1484 goto out;
1485 ret = btrfs_qgroup_account_extents(trans);
1486 if (ret < 0)
1487 goto out;
1488
1489 /* Now qgroup are all updated, we can inherit it to new qgroups */
1490 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1491 inherit);
1492 if (ret < 0)
1493 goto out;
1494
1495 /*
1496 * Now we do a simplified commit transaction, which will:
1497 * 1) commit all subvolume and extent tree
1498 * To ensure all subvolume and extent tree have a valid
1499 * commit_root to accounting later insert_dir_item()
1500 * 2) write all btree blocks onto disk
1501 * This is to make sure later btree modification will be cowed
1502 * Or commit_root can be populated and cause wrong qgroup numbers
1503 * In this simplified commit, we don't really care about other trees
1504 * like chunk and root tree, as they won't affect qgroup.
1505 * And we don't write super to avoid half committed status.
1506 */
1507 ret = commit_cowonly_roots(trans);
1508 if (ret)
1509 goto out;
1510 switch_commit_roots(trans);
1511 ret = btrfs_write_and_wait_transaction(trans);
1512 if (ret)
1513 btrfs_handle_fs_error(fs_info, ret,
1514 "Error while writing out transaction for qgroup");
1515
1516out:
1517 mutex_unlock(&fs_info->tree_log_mutex);
1518
1519 /*
1520 * Force parent root to be updated, as we recorded it before so its
1521 * last_trans == cur_transid.
1522 * Or it won't be committed again onto disk after later
1523 * insert_dir_item()
1524 */
1525 if (!ret)
1526 ret = record_root_in_trans(trans, parent, 1);
1527 return ret;
1528}
1529
1530/*
1531 * new snapshots need to be created at a very specific time in the
1532 * transaction commit. This does the actual creation.
1533 *
1534 * Note:
1535 * If the error which may affect the commitment of the current transaction
1536 * happens, we should return the error number. If the error which just affect
1537 * the creation of the pending snapshots, just return 0.
1538 */
1539static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1540 struct btrfs_pending_snapshot *pending)
1541{
1542
1543 struct btrfs_fs_info *fs_info = trans->fs_info;
1544 struct btrfs_key key;
1545 struct btrfs_root_item *new_root_item;
1546 struct btrfs_root *tree_root = fs_info->tree_root;
1547 struct btrfs_root *root = pending->root;
1548 struct btrfs_root *parent_root;
1549 struct btrfs_block_rsv *rsv;
1550 struct inode *parent_inode;
1551 struct btrfs_path *path;
1552 struct btrfs_dir_item *dir_item;
1553 struct dentry *dentry;
1554 struct extent_buffer *tmp;
1555 struct extent_buffer *old;
1556 struct timespec64 cur_time;
1557 int ret = 0;
1558 u64 to_reserve = 0;
1559 u64 index = 0;
1560 u64 objectid;
1561 u64 root_flags;
1562
1563 ASSERT(pending->path);
1564 path = pending->path;
1565
1566 ASSERT(pending->root_item);
1567 new_root_item = pending->root_item;
1568
1569 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1570 if (pending->error)
1571 goto no_free_objectid;
1572
1573 /*
1574 * Make qgroup to skip current new snapshot's qgroupid, as it is
1575 * accounted by later btrfs_qgroup_inherit().
1576 */
1577 btrfs_set_skip_qgroup(trans, objectid);
1578
1579 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1580
1581 if (to_reserve > 0) {
1582 pending->error = btrfs_block_rsv_add(root,
1583 &pending->block_rsv,
1584 to_reserve,
1585 BTRFS_RESERVE_NO_FLUSH);
1586 if (pending->error)
1587 goto clear_skip_qgroup;
1588 }
1589
1590 key.objectid = objectid;
1591 key.offset = (u64)-1;
1592 key.type = BTRFS_ROOT_ITEM_KEY;
1593
1594 rsv = trans->block_rsv;
1595 trans->block_rsv = &pending->block_rsv;
1596 trans->bytes_reserved = trans->block_rsv->reserved;
1597 trace_btrfs_space_reservation(fs_info, "transaction",
1598 trans->transid,
1599 trans->bytes_reserved, 1);
1600 dentry = pending->dentry;
1601 parent_inode = pending->dir;
1602 parent_root = BTRFS_I(parent_inode)->root;
1603 ret = record_root_in_trans(trans, parent_root, 0);
1604 if (ret)
1605 goto fail;
1606 cur_time = current_time(parent_inode);
1607
1608 /*
1609 * insert the directory item
1610 */
1611 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1612 BUG_ON(ret); /* -ENOMEM */
1613
1614 /* check if there is a file/dir which has the same name. */
1615 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1616 btrfs_ino(BTRFS_I(parent_inode)),
1617 dentry->d_name.name,
1618 dentry->d_name.len, 0);
1619 if (dir_item != NULL && !IS_ERR(dir_item)) {
1620 pending->error = -EEXIST;
1621 goto dir_item_existed;
1622 } else if (IS_ERR(dir_item)) {
1623 ret = PTR_ERR(dir_item);
1624 btrfs_abort_transaction(trans, ret);
1625 goto fail;
1626 }
1627 btrfs_release_path(path);
1628
1629 /*
1630 * pull in the delayed directory update
1631 * and the delayed inode item
1632 * otherwise we corrupt the FS during
1633 * snapshot
1634 */
1635 ret = btrfs_run_delayed_items(trans);
1636 if (ret) { /* Transaction aborted */
1637 btrfs_abort_transaction(trans, ret);
1638 goto fail;
1639 }
1640
1641 ret = record_root_in_trans(trans, root, 0);
1642 if (ret) {
1643 btrfs_abort_transaction(trans, ret);
1644 goto fail;
1645 }
1646 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1647 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1648 btrfs_check_and_init_root_item(new_root_item);
1649
1650 root_flags = btrfs_root_flags(new_root_item);
1651 if (pending->readonly)
1652 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1653 else
1654 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1655 btrfs_set_root_flags(new_root_item, root_flags);
1656
1657 btrfs_set_root_generation_v2(new_root_item,
1658 trans->transid);
1659 generate_random_guid(new_root_item->uuid);
1660 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1661 BTRFS_UUID_SIZE);
1662 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1663 memset(new_root_item->received_uuid, 0,
1664 sizeof(new_root_item->received_uuid));
1665 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1666 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1667 btrfs_set_root_stransid(new_root_item, 0);
1668 btrfs_set_root_rtransid(new_root_item, 0);
1669 }
1670 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1671 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1672 btrfs_set_root_otransid(new_root_item, trans->transid);
1673
1674 old = btrfs_lock_root_node(root);
1675 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1676 BTRFS_NESTING_COW);
1677 if (ret) {
1678 btrfs_tree_unlock(old);
1679 free_extent_buffer(old);
1680 btrfs_abort_transaction(trans, ret);
1681 goto fail;
1682 }
1683
1684 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1685 /* clean up in any case */
1686 btrfs_tree_unlock(old);
1687 free_extent_buffer(old);
1688 if (ret) {
1689 btrfs_abort_transaction(trans, ret);
1690 goto fail;
1691 }
1692 /* see comments in should_cow_block() */
1693 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1694 smp_wmb();
1695
1696 btrfs_set_root_node(new_root_item, tmp);
1697 /* record when the snapshot was created in key.offset */
1698 key.offset = trans->transid;
1699 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1700 btrfs_tree_unlock(tmp);
1701 free_extent_buffer(tmp);
1702 if (ret) {
1703 btrfs_abort_transaction(trans, ret);
1704 goto fail;
1705 }
1706
1707 /*
1708 * insert root back/forward references
1709 */
1710 ret = btrfs_add_root_ref(trans, objectid,
1711 parent_root->root_key.objectid,
1712 btrfs_ino(BTRFS_I(parent_inode)), index,
1713 dentry->d_name.name, dentry->d_name.len);
1714 if (ret) {
1715 btrfs_abort_transaction(trans, ret);
1716 goto fail;
1717 }
1718
1719 key.offset = (u64)-1;
1720 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1721 if (IS_ERR(pending->snap)) {
1722 ret = PTR_ERR(pending->snap);
1723 pending->snap = NULL;
1724 btrfs_abort_transaction(trans, ret);
1725 goto fail;
1726 }
1727
1728 ret = btrfs_reloc_post_snapshot(trans, pending);
1729 if (ret) {
1730 btrfs_abort_transaction(trans, ret);
1731 goto fail;
1732 }
1733
1734 /*
1735 * Do special qgroup accounting for snapshot, as we do some qgroup
1736 * snapshot hack to do fast snapshot.
1737 * To co-operate with that hack, we do hack again.
1738 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1739 */
1740 ret = qgroup_account_snapshot(trans, root, parent_root,
1741 pending->inherit, objectid);
1742 if (ret < 0)
1743 goto fail;
1744
1745 ret = btrfs_insert_dir_item(trans, dentry->d_name.name,
1746 dentry->d_name.len, BTRFS_I(parent_inode),
1747 &key, BTRFS_FT_DIR, index);
1748 /* We have check then name at the beginning, so it is impossible. */
1749 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1750 if (ret) {
1751 btrfs_abort_transaction(trans, ret);
1752 goto fail;
1753 }
1754
1755 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1756 dentry->d_name.len * 2);
1757 parent_inode->i_mtime = parent_inode->i_ctime =
1758 current_time(parent_inode);
1759 ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
1760 if (ret) {
1761 btrfs_abort_transaction(trans, ret);
1762 goto fail;
1763 }
1764 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1765 BTRFS_UUID_KEY_SUBVOL,
1766 objectid);
1767 if (ret) {
1768 btrfs_abort_transaction(trans, ret);
1769 goto fail;
1770 }
1771 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1772 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1773 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1774 objectid);
1775 if (ret && ret != -EEXIST) {
1776 btrfs_abort_transaction(trans, ret);
1777 goto fail;
1778 }
1779 }
1780
1781fail:
1782 pending->error = ret;
1783dir_item_existed:
1784 trans->block_rsv = rsv;
1785 trans->bytes_reserved = 0;
1786clear_skip_qgroup:
1787 btrfs_clear_skip_qgroup(trans);
1788no_free_objectid:
1789 kfree(new_root_item);
1790 pending->root_item = NULL;
1791 btrfs_free_path(path);
1792 pending->path = NULL;
1793
1794 return ret;
1795}
1796
1797/*
1798 * create all the snapshots we've scheduled for creation
1799 */
1800static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1801{
1802 struct btrfs_pending_snapshot *pending, *next;
1803 struct list_head *head = &trans->transaction->pending_snapshots;
1804 int ret = 0;
1805
1806 list_for_each_entry_safe(pending, next, head, list) {
1807 list_del(&pending->list);
1808 ret = create_pending_snapshot(trans, pending);
1809 if (ret)
1810 break;
1811 }
1812 return ret;
1813}
1814
1815static void update_super_roots(struct btrfs_fs_info *fs_info)
1816{
1817 struct btrfs_root_item *root_item;
1818 struct btrfs_super_block *super;
1819
1820 super = fs_info->super_copy;
1821
1822 root_item = &fs_info->chunk_root->root_item;
1823 super->chunk_root = root_item->bytenr;
1824 super->chunk_root_generation = root_item->generation;
1825 super->chunk_root_level = root_item->level;
1826
1827 root_item = &fs_info->tree_root->root_item;
1828 super->root = root_item->bytenr;
1829 super->generation = root_item->generation;
1830 super->root_level = root_item->level;
1831 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1832 super->cache_generation = root_item->generation;
1833 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1834 super->cache_generation = 0;
1835 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1836 super->uuid_tree_generation = root_item->generation;
1837}
1838
1839int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1840{
1841 struct btrfs_transaction *trans;
1842 int ret = 0;
1843
1844 spin_lock(&info->trans_lock);
1845 trans = info->running_transaction;
1846 if (trans)
1847 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1848 spin_unlock(&info->trans_lock);
1849 return ret;
1850}
1851
1852int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1853{
1854 struct btrfs_transaction *trans;
1855 int ret = 0;
1856
1857 spin_lock(&info->trans_lock);
1858 trans = info->running_transaction;
1859 if (trans)
1860 ret = is_transaction_blocked(trans);
1861 spin_unlock(&info->trans_lock);
1862 return ret;
1863}
1864
1865/*
1866 * commit transactions asynchronously. once btrfs_commit_transaction_async
1867 * returns, any subsequent transaction will not be allowed to join.
1868 */
1869struct btrfs_async_commit {
1870 struct btrfs_trans_handle *newtrans;
1871 struct work_struct work;
1872};
1873
1874static void do_async_commit(struct work_struct *work)
1875{
1876 struct btrfs_async_commit *ac =
1877 container_of(work, struct btrfs_async_commit, work);
1878
1879 /*
1880 * We've got freeze protection passed with the transaction.
1881 * Tell lockdep about it.
1882 */
1883 if (ac->newtrans->type & __TRANS_FREEZABLE)
1884 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
1885
1886 current->journal_info = ac->newtrans;
1887
1888 btrfs_commit_transaction(ac->newtrans);
1889 kfree(ac);
1890}
1891
1892int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1893{
1894 struct btrfs_fs_info *fs_info = trans->fs_info;
1895 struct btrfs_async_commit *ac;
1896 struct btrfs_transaction *cur_trans;
1897
1898 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1899 if (!ac)
1900 return -ENOMEM;
1901
1902 INIT_WORK(&ac->work, do_async_commit);
1903 ac->newtrans = btrfs_join_transaction(trans->root);
1904 if (IS_ERR(ac->newtrans)) {
1905 int err = PTR_ERR(ac->newtrans);
1906 kfree(ac);
1907 return err;
1908 }
1909
1910 /* take transaction reference */
1911 cur_trans = trans->transaction;
1912 refcount_inc(&cur_trans->use_count);
1913
1914 btrfs_end_transaction(trans);
1915
1916 /*
1917 * Tell lockdep we've released the freeze rwsem, since the
1918 * async commit thread will be the one to unlock it.
1919 */
1920 if (ac->newtrans->type & __TRANS_FREEZABLE)
1921 __sb_writers_release(fs_info->sb, SB_FREEZE_FS);
1922
1923 schedule_work(&ac->work);
1924 /*
1925 * Wait for the current transaction commit to start and block
1926 * subsequent transaction joins
1927 */
1928 wait_event(fs_info->transaction_blocked_wait,
1929 cur_trans->state >= TRANS_STATE_COMMIT_START ||
1930 TRANS_ABORTED(cur_trans));
1931 if (current->journal_info == trans)
1932 current->journal_info = NULL;
1933
1934 btrfs_put_transaction(cur_trans);
1935 return 0;
1936}
1937
1938
1939static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1940{
1941 struct btrfs_fs_info *fs_info = trans->fs_info;
1942 struct btrfs_transaction *cur_trans = trans->transaction;
1943
1944 WARN_ON(refcount_read(&trans->use_count) > 1);
1945
1946 btrfs_abort_transaction(trans, err);
1947
1948 spin_lock(&fs_info->trans_lock);
1949
1950 /*
1951 * If the transaction is removed from the list, it means this
1952 * transaction has been committed successfully, so it is impossible
1953 * to call the cleanup function.
1954 */
1955 BUG_ON(list_empty(&cur_trans->list));
1956
1957 if (cur_trans == fs_info->running_transaction) {
1958 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1959 spin_unlock(&fs_info->trans_lock);
1960 wait_event(cur_trans->writer_wait,
1961 atomic_read(&cur_trans->num_writers) == 1);
1962
1963 spin_lock(&fs_info->trans_lock);
1964 }
1965
1966 /*
1967 * Now that we know no one else is still using the transaction we can
1968 * remove the transaction from the list of transactions. This avoids
1969 * the transaction kthread from cleaning up the transaction while some
1970 * other task is still using it, which could result in a use-after-free
1971 * on things like log trees, as it forces the transaction kthread to
1972 * wait for this transaction to be cleaned up by us.
1973 */
1974 list_del_init(&cur_trans->list);
1975
1976 spin_unlock(&fs_info->trans_lock);
1977
1978 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
1979
1980 spin_lock(&fs_info->trans_lock);
1981 if (cur_trans == fs_info->running_transaction)
1982 fs_info->running_transaction = NULL;
1983 spin_unlock(&fs_info->trans_lock);
1984
1985 if (trans->type & __TRANS_FREEZABLE)
1986 sb_end_intwrite(fs_info->sb);
1987 btrfs_put_transaction(cur_trans);
1988 btrfs_put_transaction(cur_trans);
1989
1990 trace_btrfs_transaction_commit(trans->root);
1991
1992 if (current->journal_info == trans)
1993 current->journal_info = NULL;
1994 btrfs_scrub_cancel(fs_info);
1995
1996 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1997}
1998
1999/*
2000 * Release reserved delayed ref space of all pending block groups of the
2001 * transaction and remove them from the list
2002 */
2003static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2004{
2005 struct btrfs_fs_info *fs_info = trans->fs_info;
2006 struct btrfs_block_group *block_group, *tmp;
2007
2008 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2009 btrfs_delayed_refs_rsv_release(fs_info, 1);
2010 list_del_init(&block_group->bg_list);
2011 }
2012}
2013
2014static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2015{
2016 /*
2017 * We use writeback_inodes_sb here because if we used
2018 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2019 * Currently are holding the fs freeze lock, if we do an async flush
2020 * we'll do btrfs_join_transaction() and deadlock because we need to
2021 * wait for the fs freeze lock. Using the direct flushing we benefit
2022 * from already being in a transaction and our join_transaction doesn't
2023 * have to re-take the fs freeze lock.
2024 */
2025 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2026 writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2027 return 0;
2028}
2029
2030static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2031{
2032 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2033 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2034}
2035
2036int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2037{
2038 struct btrfs_fs_info *fs_info = trans->fs_info;
2039 struct btrfs_transaction *cur_trans = trans->transaction;
2040 struct btrfs_transaction *prev_trans = NULL;
2041 int ret;
2042
2043 ASSERT(refcount_read(&trans->use_count) == 1);
2044
2045 /* Stop the commit early if ->aborted is set */
2046 if (TRANS_ABORTED(cur_trans)) {
2047 ret = cur_trans->aborted;
2048 btrfs_end_transaction(trans);
2049 return ret;
2050 }
2051
2052 btrfs_trans_release_metadata(trans);
2053 trans->block_rsv = NULL;
2054
2055 /*
2056 * We only want one transaction commit doing the flushing so we do not
2057 * waste a bunch of time on lock contention on the extent root node.
2058 */
2059 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2060 &cur_trans->delayed_refs.flags)) {
2061 /*
2062 * Make a pass through all the delayed refs we have so far.
2063 * Any running threads may add more while we are here.
2064 */
2065 ret = btrfs_run_delayed_refs(trans, 0);
2066 if (ret) {
2067 btrfs_end_transaction(trans);
2068 return ret;
2069 }
2070 }
2071
2072 btrfs_create_pending_block_groups(trans);
2073
2074 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2075 int run_it = 0;
2076
2077 /* this mutex is also taken before trying to set
2078 * block groups readonly. We need to make sure
2079 * that nobody has set a block group readonly
2080 * after a extents from that block group have been
2081 * allocated for cache files. btrfs_set_block_group_ro
2082 * will wait for the transaction to commit if it
2083 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2084 *
2085 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2086 * only one process starts all the block group IO. It wouldn't
2087 * hurt to have more than one go through, but there's no
2088 * real advantage to it either.
2089 */
2090 mutex_lock(&fs_info->ro_block_group_mutex);
2091 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2092 &cur_trans->flags))
2093 run_it = 1;
2094 mutex_unlock(&fs_info->ro_block_group_mutex);
2095
2096 if (run_it) {
2097 ret = btrfs_start_dirty_block_groups(trans);
2098 if (ret) {
2099 btrfs_end_transaction(trans);
2100 return ret;
2101 }
2102 }
2103 }
2104
2105 spin_lock(&fs_info->trans_lock);
2106 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2107 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2108
2109 spin_unlock(&fs_info->trans_lock);
2110 refcount_inc(&cur_trans->use_count);
2111
2112 if (trans->in_fsync)
2113 want_state = TRANS_STATE_SUPER_COMMITTED;
2114 ret = btrfs_end_transaction(trans);
2115 wait_for_commit(cur_trans, want_state);
2116
2117 if (TRANS_ABORTED(cur_trans))
2118 ret = cur_trans->aborted;
2119
2120 btrfs_put_transaction(cur_trans);
2121
2122 return ret;
2123 }
2124
2125 cur_trans->state = TRANS_STATE_COMMIT_START;
2126 wake_up(&fs_info->transaction_blocked_wait);
2127
2128 if (cur_trans->list.prev != &fs_info->trans_list) {
2129 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2130
2131 if (trans->in_fsync)
2132 want_state = TRANS_STATE_SUPER_COMMITTED;
2133
2134 prev_trans = list_entry(cur_trans->list.prev,
2135 struct btrfs_transaction, list);
2136 if (prev_trans->state < want_state) {
2137 refcount_inc(&prev_trans->use_count);
2138 spin_unlock(&fs_info->trans_lock);
2139
2140 wait_for_commit(prev_trans, want_state);
2141
2142 ret = READ_ONCE(prev_trans->aborted);
2143
2144 btrfs_put_transaction(prev_trans);
2145 if (ret)
2146 goto cleanup_transaction;
2147 } else {
2148 spin_unlock(&fs_info->trans_lock);
2149 }
2150 } else {
2151 spin_unlock(&fs_info->trans_lock);
2152 /*
2153 * The previous transaction was aborted and was already removed
2154 * from the list of transactions at fs_info->trans_list. So we
2155 * abort to prevent writing a new superblock that reflects a
2156 * corrupt state (pointing to trees with unwritten nodes/leafs).
2157 */
2158 if (test_bit(BTRFS_FS_STATE_TRANS_ABORTED, &fs_info->fs_state)) {
2159 ret = -EROFS;
2160 goto cleanup_transaction;
2161 }
2162 }
2163
2164 extwriter_counter_dec(cur_trans, trans->type);
2165
2166 ret = btrfs_start_delalloc_flush(fs_info);
2167 if (ret)
2168 goto cleanup_transaction;
2169
2170 ret = btrfs_run_delayed_items(trans);
2171 if (ret)
2172 goto cleanup_transaction;
2173
2174 wait_event(cur_trans->writer_wait,
2175 extwriter_counter_read(cur_trans) == 0);
2176
2177 /* some pending stuffs might be added after the previous flush. */
2178 ret = btrfs_run_delayed_items(trans);
2179 if (ret)
2180 goto cleanup_transaction;
2181
2182 btrfs_wait_delalloc_flush(fs_info);
2183
2184 /*
2185 * Wait for all ordered extents started by a fast fsync that joined this
2186 * transaction. Otherwise if this transaction commits before the ordered
2187 * extents complete we lose logged data after a power failure.
2188 */
2189 wait_event(cur_trans->pending_wait,
2190 atomic_read(&cur_trans->pending_ordered) == 0);
2191
2192 btrfs_scrub_pause(fs_info);
2193 /*
2194 * Ok now we need to make sure to block out any other joins while we
2195 * commit the transaction. We could have started a join before setting
2196 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2197 */
2198 spin_lock(&fs_info->trans_lock);
2199 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2200 spin_unlock(&fs_info->trans_lock);
2201 wait_event(cur_trans->writer_wait,
2202 atomic_read(&cur_trans->num_writers) == 1);
2203
2204 if (TRANS_ABORTED(cur_trans)) {
2205 ret = cur_trans->aborted;
2206 goto scrub_continue;
2207 }
2208 /*
2209 * the reloc mutex makes sure that we stop
2210 * the balancing code from coming in and moving
2211 * extents around in the middle of the commit
2212 */
2213 mutex_lock(&fs_info->reloc_mutex);
2214
2215 /*
2216 * We needn't worry about the delayed items because we will
2217 * deal with them in create_pending_snapshot(), which is the
2218 * core function of the snapshot creation.
2219 */
2220 ret = create_pending_snapshots(trans);
2221 if (ret)
2222 goto unlock_reloc;
2223
2224 /*
2225 * We insert the dir indexes of the snapshots and update the inode
2226 * of the snapshots' parents after the snapshot creation, so there
2227 * are some delayed items which are not dealt with. Now deal with
2228 * them.
2229 *
2230 * We needn't worry that this operation will corrupt the snapshots,
2231 * because all the tree which are snapshoted will be forced to COW
2232 * the nodes and leaves.
2233 */
2234 ret = btrfs_run_delayed_items(trans);
2235 if (ret)
2236 goto unlock_reloc;
2237
2238 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2239 if (ret)
2240 goto unlock_reloc;
2241
2242 /*
2243 * make sure none of the code above managed to slip in a
2244 * delayed item
2245 */
2246 btrfs_assert_delayed_root_empty(fs_info);
2247
2248 WARN_ON(cur_trans != trans->transaction);
2249
2250 /* btrfs_commit_tree_roots is responsible for getting the
2251 * various roots consistent with each other. Every pointer
2252 * in the tree of tree roots has to point to the most up to date
2253 * root for every subvolume and other tree. So, we have to keep
2254 * the tree logging code from jumping in and changing any
2255 * of the trees.
2256 *
2257 * At this point in the commit, there can't be any tree-log
2258 * writers, but a little lower down we drop the trans mutex
2259 * and let new people in. By holding the tree_log_mutex
2260 * from now until after the super is written, we avoid races
2261 * with the tree-log code.
2262 */
2263 mutex_lock(&fs_info->tree_log_mutex);
2264
2265 ret = commit_fs_roots(trans);
2266 if (ret)
2267 goto unlock_tree_log;
2268
2269 /*
2270 * Since the transaction is done, we can apply the pending changes
2271 * before the next transaction.
2272 */
2273 btrfs_apply_pending_changes(fs_info);
2274
2275 /* commit_fs_roots gets rid of all the tree log roots, it is now
2276 * safe to free the root of tree log roots
2277 */
2278 btrfs_free_log_root_tree(trans, fs_info);
2279
2280 /*
2281 * Since fs roots are all committed, we can get a quite accurate
2282 * new_roots. So let's do quota accounting.
2283 */
2284 ret = btrfs_qgroup_account_extents(trans);
2285 if (ret < 0)
2286 goto unlock_tree_log;
2287
2288 ret = commit_cowonly_roots(trans);
2289 if (ret)
2290 goto unlock_tree_log;
2291
2292 /*
2293 * The tasks which save the space cache and inode cache may also
2294 * update ->aborted, check it.
2295 */
2296 if (TRANS_ABORTED(cur_trans)) {
2297 ret = cur_trans->aborted;
2298 goto unlock_tree_log;
2299 }
2300
2301 cur_trans = fs_info->running_transaction;
2302
2303 btrfs_set_root_node(&fs_info->tree_root->root_item,
2304 fs_info->tree_root->node);
2305 list_add_tail(&fs_info->tree_root->dirty_list,
2306 &cur_trans->switch_commits);
2307
2308 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2309 fs_info->chunk_root->node);
2310 list_add_tail(&fs_info->chunk_root->dirty_list,
2311 &cur_trans->switch_commits);
2312
2313 switch_commit_roots(trans);
2314
2315 ASSERT(list_empty(&cur_trans->dirty_bgs));
2316 ASSERT(list_empty(&cur_trans->io_bgs));
2317 update_super_roots(fs_info);
2318
2319 btrfs_set_super_log_root(fs_info->super_copy, 0);
2320 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2321 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2322 sizeof(*fs_info->super_copy));
2323
2324 btrfs_commit_device_sizes(cur_trans);
2325
2326 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2327 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2328
2329 btrfs_trans_release_chunk_metadata(trans);
2330
2331 spin_lock(&fs_info->trans_lock);
2332 cur_trans->state = TRANS_STATE_UNBLOCKED;
2333 fs_info->running_transaction = NULL;
2334 spin_unlock(&fs_info->trans_lock);
2335 mutex_unlock(&fs_info->reloc_mutex);
2336
2337 wake_up(&fs_info->transaction_wait);
2338
2339 ret = btrfs_write_and_wait_transaction(trans);
2340 if (ret) {
2341 btrfs_handle_fs_error(fs_info, ret,
2342 "Error while writing out transaction");
2343 /*
2344 * reloc_mutex has been unlocked, tree_log_mutex is still held
2345 * but we can't jump to unlock_tree_log causing double unlock
2346 */
2347 mutex_unlock(&fs_info->tree_log_mutex);
2348 goto scrub_continue;
2349 }
2350
2351 /*
2352 * At this point, we should have written all the tree blocks allocated
2353 * in this transaction. So it's now safe to free the redirtyied extent
2354 * buffers.
2355 */
2356 btrfs_free_redirty_list(cur_trans);
2357
2358 ret = write_all_supers(fs_info, 0);
2359 /*
2360 * the super is written, we can safely allow the tree-loggers
2361 * to go about their business
2362 */
2363 mutex_unlock(&fs_info->tree_log_mutex);
2364 if (ret)
2365 goto scrub_continue;
2366
2367 /*
2368 * We needn't acquire the lock here because there is no other task
2369 * which can change it.
2370 */
2371 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2372 wake_up(&cur_trans->commit_wait);
2373
2374 btrfs_finish_extent_commit(trans);
2375
2376 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2377 btrfs_clear_space_info_full(fs_info);
2378
2379 fs_info->last_trans_committed = cur_trans->transid;
2380 /*
2381 * We needn't acquire the lock here because there is no other task
2382 * which can change it.
2383 */
2384 cur_trans->state = TRANS_STATE_COMPLETED;
2385 wake_up(&cur_trans->commit_wait);
2386
2387 spin_lock(&fs_info->trans_lock);
2388 list_del_init(&cur_trans->list);
2389 spin_unlock(&fs_info->trans_lock);
2390
2391 btrfs_put_transaction(cur_trans);
2392 btrfs_put_transaction(cur_trans);
2393
2394 if (trans->type & __TRANS_FREEZABLE)
2395 sb_end_intwrite(fs_info->sb);
2396
2397 trace_btrfs_transaction_commit(trans->root);
2398
2399 btrfs_scrub_continue(fs_info);
2400
2401 if (current->journal_info == trans)
2402 current->journal_info = NULL;
2403
2404 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2405
2406 return ret;
2407
2408unlock_tree_log:
2409 mutex_unlock(&fs_info->tree_log_mutex);
2410unlock_reloc:
2411 mutex_unlock(&fs_info->reloc_mutex);
2412scrub_continue:
2413 btrfs_scrub_continue(fs_info);
2414cleanup_transaction:
2415 btrfs_trans_release_metadata(trans);
2416 btrfs_cleanup_pending_block_groups(trans);
2417 btrfs_trans_release_chunk_metadata(trans);
2418 trans->block_rsv = NULL;
2419 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2420 if (current->journal_info == trans)
2421 current->journal_info = NULL;
2422 cleanup_transaction(trans, ret);
2423
2424 return ret;
2425}
2426
2427/*
2428 * return < 0 if error
2429 * 0 if there are no more dead_roots at the time of call
2430 * 1 there are more to be processed, call me again
2431 *
2432 * The return value indicates there are certainly more snapshots to delete, but
2433 * if there comes a new one during processing, it may return 0. We don't mind,
2434 * because btrfs_commit_super will poke cleaner thread and it will process it a
2435 * few seconds later.
2436 */
2437int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2438{
2439 int ret;
2440 struct btrfs_fs_info *fs_info = root->fs_info;
2441
2442 spin_lock(&fs_info->trans_lock);
2443 if (list_empty(&fs_info->dead_roots)) {
2444 spin_unlock(&fs_info->trans_lock);
2445 return 0;
2446 }
2447 root = list_first_entry(&fs_info->dead_roots,
2448 struct btrfs_root, root_list);
2449 list_del_init(&root->root_list);
2450 spin_unlock(&fs_info->trans_lock);
2451
2452 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2453
2454 btrfs_kill_all_delayed_nodes(root);
2455
2456 if (btrfs_header_backref_rev(root->node) <
2457 BTRFS_MIXED_BACKREF_REV)
2458 ret = btrfs_drop_snapshot(root, 0, 0);
2459 else
2460 ret = btrfs_drop_snapshot(root, 1, 0);
2461
2462 btrfs_put_root(root);
2463 return (ret < 0) ? 0 : 1;
2464}
2465
2466void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2467{
2468 unsigned long prev;
2469 unsigned long bit;
2470
2471 prev = xchg(&fs_info->pending_changes, 0);
2472 if (!prev)
2473 return;
2474
2475 bit = 1 << BTRFS_PENDING_COMMIT;
2476 if (prev & bit)
2477 btrfs_debug(fs_info, "pending commit done");
2478 prev &= ~bit;
2479
2480 if (prev)
2481 btrfs_warn(fs_info,
2482 "unknown pending changes left 0x%lx, ignoring", prev);
2483}