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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 "fs.h"
27#include "accessors.h"
28#include "extent-tree.h"
29#include "root-tree.h"
30#include "dir-item.h"
31#include "uuid-tree.h"
32#include "ioctl.h"
33#include "relocation.h"
34#include "scrub.h"
35
36static struct kmem_cache *btrfs_trans_handle_cachep;
37
38/*
39 * Transaction states and transitions
40 *
41 * No running transaction (fs tree blocks are not modified)
42 * |
43 * | To next stage:
44 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
45 * V
46 * Transaction N [[TRANS_STATE_RUNNING]]
47 * |
48 * | New trans handles can be attached to transaction N by calling all
49 * | start_transaction() variants.
50 * |
51 * | To next stage:
52 * | Call btrfs_commit_transaction() on any trans handle attached to
53 * | transaction N
54 * V
55 * Transaction N [[TRANS_STATE_COMMIT_PREP]]
56 * |
57 * | If there are simultaneous calls to btrfs_commit_transaction() one will win
58 * | the race and the rest will wait for the winner to commit the transaction.
59 * |
60 * | The winner will wait for previous running transaction to completely finish
61 * | if there is one.
62 * |
63 * Transaction N [[TRANS_STATE_COMMIT_START]]
64 * |
65 * | Then one of the following happens:
66 * | - Wait for all other trans handle holders to release.
67 * | The btrfs_commit_transaction() caller will do the commit work.
68 * | - Wait for current transaction to be committed by others.
69 * | Other btrfs_commit_transaction() caller will do the commit work.
70 * |
71 * | At this stage, only btrfs_join_transaction*() variants can attach
72 * | to this running transaction.
73 * | All other variants will wait for current one to finish and attach to
74 * | transaction N+1.
75 * |
76 * | To next stage:
77 * | Caller is chosen to commit transaction N, and all other trans handle
78 * | haven been released.
79 * V
80 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
81 * |
82 * | The heavy lifting transaction work is started.
83 * | From running delayed refs (modifying extent tree) to creating pending
84 * | snapshots, running qgroups.
85 * | In short, modify supporting trees to reflect modifications of subvolume
86 * | trees.
87 * |
88 * | At this stage, all start_transaction() calls will wait for this
89 * | transaction to finish and attach to transaction N+1.
90 * |
91 * | To next stage:
92 * | Until all supporting trees are updated.
93 * V
94 * Transaction N [[TRANS_STATE_UNBLOCKED]]
95 * | Transaction N+1
96 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
97 * | need to write them back to disk and update |
98 * | super blocks. |
99 * | |
100 * | At this stage, new transaction is allowed to |
101 * | start. |
102 * | All new start_transaction() calls will be |
103 * | attached to transid N+1. |
104 * | |
105 * | To next stage: |
106 * | Until all tree blocks are super blocks are |
107 * | written to block devices |
108 * V |
109 * Transaction N [[TRANS_STATE_COMPLETED]] V
110 * All tree blocks and super blocks are written. Transaction N+1
111 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
112 * data structures will be cleaned up. | Life goes on
113 */
114static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
115 [TRANS_STATE_RUNNING] = 0U,
116 [TRANS_STATE_COMMIT_PREP] = 0U,
117 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
118 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
119 __TRANS_ATTACH |
120 __TRANS_JOIN |
121 __TRANS_JOIN_NOSTART),
122 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
123 __TRANS_ATTACH |
124 __TRANS_JOIN |
125 __TRANS_JOIN_NOLOCK |
126 __TRANS_JOIN_NOSTART),
127 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
128 __TRANS_ATTACH |
129 __TRANS_JOIN |
130 __TRANS_JOIN_NOLOCK |
131 __TRANS_JOIN_NOSTART),
132 [TRANS_STATE_COMPLETED] = (__TRANS_START |
133 __TRANS_ATTACH |
134 __TRANS_JOIN |
135 __TRANS_JOIN_NOLOCK |
136 __TRANS_JOIN_NOSTART),
137};
138
139void btrfs_put_transaction(struct btrfs_transaction *transaction)
140{
141 WARN_ON(refcount_read(&transaction->use_count) == 0);
142 if (refcount_dec_and_test(&transaction->use_count)) {
143 BUG_ON(!list_empty(&transaction->list));
144 WARN_ON(!xa_empty(&transaction->delayed_refs.head_refs));
145 WARN_ON(!xa_empty(&transaction->delayed_refs.dirty_extents));
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 const int abort_error = cur_trans->aborted;
278
279 spin_unlock(&fs_info->trans_lock);
280 return abort_error;
281 }
282 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
283 spin_unlock(&fs_info->trans_lock);
284 return -EBUSY;
285 }
286 refcount_inc(&cur_trans->use_count);
287 atomic_inc(&cur_trans->num_writers);
288 extwriter_counter_inc(cur_trans, type);
289 spin_unlock(&fs_info->trans_lock);
290 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
291 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
292 return 0;
293 }
294 spin_unlock(&fs_info->trans_lock);
295
296 /*
297 * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the
298 * current transaction, and commit it. If there is no transaction, just
299 * return ENOENT.
300 */
301 if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART)
302 return -ENOENT;
303
304 /*
305 * JOIN_NOLOCK only happens during the transaction commit, so
306 * it is impossible that ->running_transaction is NULL
307 */
308 BUG_ON(type == TRANS_JOIN_NOLOCK);
309
310 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
311 if (!cur_trans)
312 return -ENOMEM;
313
314 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
315 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
316
317 spin_lock(&fs_info->trans_lock);
318 if (fs_info->running_transaction) {
319 /*
320 * someone started a transaction after we unlocked. Make sure
321 * to redo the checks above
322 */
323 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
324 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
325 kfree(cur_trans);
326 goto loop;
327 } else if (BTRFS_FS_ERROR(fs_info)) {
328 spin_unlock(&fs_info->trans_lock);
329 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
330 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
331 kfree(cur_trans);
332 return -EROFS;
333 }
334
335 cur_trans->fs_info = fs_info;
336 atomic_set(&cur_trans->pending_ordered, 0);
337 init_waitqueue_head(&cur_trans->pending_wait);
338 atomic_set(&cur_trans->num_writers, 1);
339 extwriter_counter_init(cur_trans, type);
340 init_waitqueue_head(&cur_trans->writer_wait);
341 init_waitqueue_head(&cur_trans->commit_wait);
342 cur_trans->state = TRANS_STATE_RUNNING;
343 /*
344 * One for this trans handle, one so it will live on until we
345 * commit the transaction.
346 */
347 refcount_set(&cur_trans->use_count, 2);
348 cur_trans->flags = 0;
349 cur_trans->start_time = ktime_get_seconds();
350
351 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
352
353 xa_init(&cur_trans->delayed_refs.head_refs);
354 xa_init(&cur_trans->delayed_refs.dirty_extents);
355
356 /*
357 * although the tree mod log is per file system and not per transaction,
358 * the log must never go across transaction boundaries.
359 */
360 smp_mb();
361 if (!list_empty(&fs_info->tree_mod_seq_list))
362 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
363 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
364 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
365 atomic64_set(&fs_info->tree_mod_seq, 0);
366
367 spin_lock_init(&cur_trans->delayed_refs.lock);
368
369 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
370 INIT_LIST_HEAD(&cur_trans->dev_update_list);
371 INIT_LIST_HEAD(&cur_trans->switch_commits);
372 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
373 INIT_LIST_HEAD(&cur_trans->io_bgs);
374 INIT_LIST_HEAD(&cur_trans->dropped_roots);
375 mutex_init(&cur_trans->cache_write_mutex);
376 spin_lock_init(&cur_trans->dirty_bgs_lock);
377 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
378 spin_lock_init(&cur_trans->dropped_roots_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 btrfs_set_fs_generation(fs_info, fs_info->generation + 1);
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 btrfs_get_root_last_trans(root) < 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 (btrfs_get_root_last_trans(root) == 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)btrfs_root_id(root),
429 BTRFS_ROOT_TRANS_TAG);
430 spin_unlock(&fs_info->fs_roots_radix_lock);
431 btrfs_set_root_last_trans(root, 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)btrfs_root_id(root),
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 (btrfs_get_root_last_trans(root) == 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 btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID ||
553 root->reloc_root)
554 return false;
555
556 return true;
557}
558
559static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info,
560 enum btrfs_reserve_flush_enum flush,
561 u64 num_bytes,
562 u64 *delayed_refs_bytes)
563{
564 struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info;
565 u64 bytes = num_bytes + *delayed_refs_bytes;
566 int ret;
567
568 /*
569 * We want to reserve all the bytes we may need all at once, so we only
570 * do 1 enospc flushing cycle per transaction start.
571 */
572 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
573
574 /*
575 * If we are an emergency flush, which can steal from the global block
576 * reserve, then attempt to not reserve space for the delayed refs, as
577 * we will consume space for them from the global block reserve.
578 */
579 if (ret && flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
580 bytes -= *delayed_refs_bytes;
581 *delayed_refs_bytes = 0;
582 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
583 }
584
585 return ret;
586}
587
588static struct btrfs_trans_handle *
589start_transaction(struct btrfs_root *root, unsigned int num_items,
590 unsigned int type, enum btrfs_reserve_flush_enum flush,
591 bool enforce_qgroups)
592{
593 struct btrfs_fs_info *fs_info = root->fs_info;
594 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
595 struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
596 struct btrfs_trans_handle *h;
597 struct btrfs_transaction *cur_trans;
598 u64 num_bytes = 0;
599 u64 qgroup_reserved = 0;
600 u64 delayed_refs_bytes = 0;
601 bool reloc_reserved = false;
602 bool do_chunk_alloc = false;
603 int ret;
604
605 if (BTRFS_FS_ERROR(fs_info))
606 return ERR_PTR(-EROFS);
607
608 if (current->journal_info) {
609 WARN_ON(type & TRANS_EXTWRITERS);
610 h = current->journal_info;
611 refcount_inc(&h->use_count);
612 WARN_ON(refcount_read(&h->use_count) > 2);
613 h->orig_rsv = h->block_rsv;
614 h->block_rsv = NULL;
615 goto got_it;
616 }
617
618 /*
619 * Do the reservation before we join the transaction so we can do all
620 * the appropriate flushing if need be.
621 */
622 if (num_items && root != fs_info->chunk_root) {
623 qgroup_reserved = num_items * fs_info->nodesize;
624 /*
625 * Use prealloc for now, as there might be a currently running
626 * transaction that could free this reserved space prematurely
627 * by committing.
628 */
629 ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved,
630 enforce_qgroups, false);
631 if (ret)
632 return ERR_PTR(ret);
633
634 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
635 /*
636 * If we plan to insert/update/delete "num_items" from a btree,
637 * we will also generate delayed refs for extent buffers in the
638 * respective btree paths, so reserve space for the delayed refs
639 * that will be generated by the caller as it modifies btrees.
640 * Try to reserve them to avoid excessive use of the global
641 * block reserve.
642 */
643 delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items);
644
645 /*
646 * Do the reservation for the relocation root creation
647 */
648 if (need_reserve_reloc_root(root)) {
649 num_bytes += fs_info->nodesize;
650 reloc_reserved = true;
651 }
652
653 ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes,
654 &delayed_refs_bytes);
655 if (ret)
656 goto reserve_fail;
657
658 btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true);
659
660 if (trans_rsv->space_info->force_alloc)
661 do_chunk_alloc = true;
662 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
663 !btrfs_block_rsv_full(delayed_refs_rsv)) {
664 /*
665 * Some people call with btrfs_start_transaction(root, 0)
666 * because they can be throttled, but have some other mechanism
667 * for reserving space. We still want these guys to refill the
668 * delayed block_rsv so just add 1 items worth of reservation
669 * here.
670 */
671 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
672 if (ret)
673 goto reserve_fail;
674 }
675again:
676 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
677 if (!h) {
678 ret = -ENOMEM;
679 goto alloc_fail;
680 }
681
682 /*
683 * If we are JOIN_NOLOCK we're already committing a transaction and
684 * waiting on this guy, so we don't need to do the sb_start_intwrite
685 * because we're already holding a ref. We need this because we could
686 * have raced in and did an fsync() on a file which can kick a commit
687 * and then we deadlock with somebody doing a freeze.
688 *
689 * If we are ATTACH, it means we just want to catch the current
690 * transaction and commit it, so we needn't do sb_start_intwrite().
691 */
692 if (type & __TRANS_FREEZABLE)
693 sb_start_intwrite(fs_info->sb);
694
695 if (may_wait_transaction(fs_info, type))
696 wait_current_trans(fs_info);
697
698 do {
699 ret = join_transaction(fs_info, type);
700 if (ret == -EBUSY) {
701 wait_current_trans(fs_info);
702 if (unlikely(type == TRANS_ATTACH ||
703 type == TRANS_JOIN_NOSTART))
704 ret = -ENOENT;
705 }
706 } while (ret == -EBUSY);
707
708 if (ret < 0)
709 goto join_fail;
710
711 cur_trans = fs_info->running_transaction;
712
713 h->transid = cur_trans->transid;
714 h->transaction = cur_trans;
715 refcount_set(&h->use_count, 1);
716 h->fs_info = root->fs_info;
717
718 h->type = type;
719 INIT_LIST_HEAD(&h->new_bgs);
720 btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS);
721
722 smp_mb();
723 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
724 may_wait_transaction(fs_info, type)) {
725 current->journal_info = h;
726 btrfs_commit_transaction(h);
727 goto again;
728 }
729
730 if (num_bytes) {
731 trace_btrfs_space_reservation(fs_info, "transaction",
732 h->transid, num_bytes, 1);
733 h->block_rsv = trans_rsv;
734 h->bytes_reserved = num_bytes;
735 if (delayed_refs_bytes > 0) {
736 trace_btrfs_space_reservation(fs_info,
737 "local_delayed_refs_rsv",
738 h->transid,
739 delayed_refs_bytes, 1);
740 h->delayed_refs_bytes_reserved = delayed_refs_bytes;
741 btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true);
742 delayed_refs_bytes = 0;
743 }
744 h->reloc_reserved = reloc_reserved;
745 }
746
747got_it:
748 if (!current->journal_info)
749 current->journal_info = h;
750
751 /*
752 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
753 * ALLOC_FORCE the first run through, and then we won't allocate for
754 * anybody else who races in later. We don't care about the return
755 * value here.
756 */
757 if (do_chunk_alloc && num_bytes) {
758 u64 flags = h->block_rsv->space_info->flags;
759
760 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
761 CHUNK_ALLOC_NO_FORCE);
762 }
763
764 /*
765 * btrfs_record_root_in_trans() needs to alloc new extents, and may
766 * call btrfs_join_transaction() while we're also starting a
767 * transaction.
768 *
769 * Thus it need to be called after current->journal_info initialized,
770 * or we can deadlock.
771 */
772 ret = btrfs_record_root_in_trans(h, root);
773 if (ret) {
774 /*
775 * The transaction handle is fully initialized and linked with
776 * other structures so it needs to be ended in case of errors,
777 * not just freed.
778 */
779 btrfs_end_transaction(h);
780 goto reserve_fail;
781 }
782 /*
783 * Now that we have found a transaction to be a part of, convert the
784 * qgroup reservation from prealloc to pertrans. A different transaction
785 * can't race in and free our pertrans out from under us.
786 */
787 if (qgroup_reserved)
788 btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
789
790 return h;
791
792join_fail:
793 if (type & __TRANS_FREEZABLE)
794 sb_end_intwrite(fs_info->sb);
795 kmem_cache_free(btrfs_trans_handle_cachep, h);
796alloc_fail:
797 if (num_bytes)
798 btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL);
799 if (delayed_refs_bytes)
800 btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info,
801 delayed_refs_bytes);
802reserve_fail:
803 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
804 return ERR_PTR(ret);
805}
806
807struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
808 unsigned int num_items)
809{
810 return start_transaction(root, num_items, TRANS_START,
811 BTRFS_RESERVE_FLUSH_ALL, true);
812}
813
814struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
815 struct btrfs_root *root,
816 unsigned int num_items)
817{
818 return start_transaction(root, num_items, TRANS_START,
819 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
820}
821
822struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
823{
824 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
825 true);
826}
827
828struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
829{
830 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
831 BTRFS_RESERVE_NO_FLUSH, true);
832}
833
834/*
835 * Similar to regular join but it never starts a transaction when none is
836 * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED.
837 * This is similar to btrfs_attach_transaction() but it allows the join to
838 * happen if the transaction commit already started but it's not yet in the
839 * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING).
840 */
841struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
842{
843 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
844 BTRFS_RESERVE_NO_FLUSH, true);
845}
846
847/*
848 * Catch the running transaction.
849 *
850 * It is used when we want to commit the current the transaction, but
851 * don't want to start a new one.
852 *
853 * Note: If this function return -ENOENT, it just means there is no
854 * running transaction. But it is possible that the inactive transaction
855 * is still in the memory, not fully on disk. If you hope there is no
856 * inactive transaction in the fs when -ENOENT is returned, you should
857 * invoke
858 * btrfs_attach_transaction_barrier()
859 */
860struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
861{
862 return start_transaction(root, 0, TRANS_ATTACH,
863 BTRFS_RESERVE_NO_FLUSH, true);
864}
865
866/*
867 * Catch the running transaction.
868 *
869 * It is similar to the above function, the difference is this one
870 * will wait for all the inactive transactions until they fully
871 * complete.
872 */
873struct btrfs_trans_handle *
874btrfs_attach_transaction_barrier(struct btrfs_root *root)
875{
876 struct btrfs_trans_handle *trans;
877
878 trans = start_transaction(root, 0, TRANS_ATTACH,
879 BTRFS_RESERVE_NO_FLUSH, true);
880 if (trans == ERR_PTR(-ENOENT)) {
881 int ret;
882
883 ret = btrfs_wait_for_commit(root->fs_info, 0);
884 if (ret)
885 return ERR_PTR(ret);
886 }
887
888 return trans;
889}
890
891/* Wait for a transaction commit to reach at least the given state. */
892static noinline void wait_for_commit(struct btrfs_transaction *commit,
893 const enum btrfs_trans_state min_state)
894{
895 struct btrfs_fs_info *fs_info = commit->fs_info;
896 u64 transid = commit->transid;
897 bool put = false;
898
899 /*
900 * At the moment this function is called with min_state either being
901 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
902 */
903 if (min_state == TRANS_STATE_COMPLETED)
904 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
905 else
906 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
907
908 while (1) {
909 wait_event(commit->commit_wait, commit->state >= min_state);
910 if (put)
911 btrfs_put_transaction(commit);
912
913 if (min_state < TRANS_STATE_COMPLETED)
914 break;
915
916 /*
917 * A transaction isn't really completed until all of the
918 * previous transactions are completed, but with fsync we can
919 * end up with SUPER_COMMITTED transactions before a COMPLETED
920 * transaction. Wait for those.
921 */
922
923 spin_lock(&fs_info->trans_lock);
924 commit = list_first_entry_or_null(&fs_info->trans_list,
925 struct btrfs_transaction,
926 list);
927 if (!commit || commit->transid > transid) {
928 spin_unlock(&fs_info->trans_lock);
929 break;
930 }
931 refcount_inc(&commit->use_count);
932 put = true;
933 spin_unlock(&fs_info->trans_lock);
934 }
935}
936
937int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
938{
939 struct btrfs_transaction *cur_trans = NULL, *t;
940 int ret = 0;
941
942 if (transid) {
943 if (transid <= btrfs_get_last_trans_committed(fs_info))
944 goto out;
945
946 /* find specified transaction */
947 spin_lock(&fs_info->trans_lock);
948 list_for_each_entry(t, &fs_info->trans_list, list) {
949 if (t->transid == transid) {
950 cur_trans = t;
951 refcount_inc(&cur_trans->use_count);
952 ret = 0;
953 break;
954 }
955 if (t->transid > transid) {
956 ret = 0;
957 break;
958 }
959 }
960 spin_unlock(&fs_info->trans_lock);
961
962 /*
963 * The specified transaction doesn't exist, or we
964 * raced with btrfs_commit_transaction
965 */
966 if (!cur_trans) {
967 if (transid > btrfs_get_last_trans_committed(fs_info))
968 ret = -EINVAL;
969 goto out;
970 }
971 } else {
972 /* find newest transaction that is committing | committed */
973 spin_lock(&fs_info->trans_lock);
974 list_for_each_entry_reverse(t, &fs_info->trans_list,
975 list) {
976 if (t->state >= TRANS_STATE_COMMIT_START) {
977 if (t->state == TRANS_STATE_COMPLETED)
978 break;
979 cur_trans = t;
980 refcount_inc(&cur_trans->use_count);
981 break;
982 }
983 }
984 spin_unlock(&fs_info->trans_lock);
985 if (!cur_trans)
986 goto out; /* nothing committing|committed */
987 }
988
989 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
990 ret = cur_trans->aborted;
991 btrfs_put_transaction(cur_trans);
992out:
993 return ret;
994}
995
996void btrfs_throttle(struct btrfs_fs_info *fs_info)
997{
998 wait_current_trans(fs_info);
999}
1000
1001bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
1002{
1003 struct btrfs_transaction *cur_trans = trans->transaction;
1004
1005 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
1006 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
1007 return true;
1008
1009 if (btrfs_check_space_for_delayed_refs(trans->fs_info))
1010 return true;
1011
1012 return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
1013}
1014
1015static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
1016
1017{
1018 struct btrfs_fs_info *fs_info = trans->fs_info;
1019
1020 if (!trans->block_rsv) {
1021 ASSERT(!trans->bytes_reserved);
1022 ASSERT(!trans->delayed_refs_bytes_reserved);
1023 return;
1024 }
1025
1026 if (!trans->bytes_reserved) {
1027 ASSERT(!trans->delayed_refs_bytes_reserved);
1028 return;
1029 }
1030
1031 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
1032 trace_btrfs_space_reservation(fs_info, "transaction",
1033 trans->transid, trans->bytes_reserved, 0);
1034 btrfs_block_rsv_release(fs_info, trans->block_rsv,
1035 trans->bytes_reserved, NULL);
1036 trans->bytes_reserved = 0;
1037
1038 if (!trans->delayed_refs_bytes_reserved)
1039 return;
1040
1041 trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv",
1042 trans->transid,
1043 trans->delayed_refs_bytes_reserved, 0);
1044 btrfs_block_rsv_release(fs_info, &trans->delayed_rsv,
1045 trans->delayed_refs_bytes_reserved, NULL);
1046 trans->delayed_refs_bytes_reserved = 0;
1047}
1048
1049static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
1050 int throttle)
1051{
1052 struct btrfs_fs_info *info = trans->fs_info;
1053 struct btrfs_transaction *cur_trans = trans->transaction;
1054 int ret = 0;
1055
1056 if (refcount_read(&trans->use_count) > 1) {
1057 refcount_dec(&trans->use_count);
1058 trans->block_rsv = trans->orig_rsv;
1059 return 0;
1060 }
1061
1062 btrfs_trans_release_metadata(trans);
1063 trans->block_rsv = NULL;
1064
1065 btrfs_create_pending_block_groups(trans);
1066
1067 btrfs_trans_release_chunk_metadata(trans);
1068
1069 if (trans->type & __TRANS_FREEZABLE)
1070 sb_end_intwrite(info->sb);
1071
1072 WARN_ON(cur_trans != info->running_transaction);
1073 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1074 atomic_dec(&cur_trans->num_writers);
1075 extwriter_counter_dec(cur_trans, trans->type);
1076
1077 cond_wake_up(&cur_trans->writer_wait);
1078
1079 btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1080 btrfs_lockdep_release(info, btrfs_trans_num_writers);
1081
1082 btrfs_put_transaction(cur_trans);
1083
1084 if (current->journal_info == trans)
1085 current->journal_info = NULL;
1086
1087 if (throttle)
1088 btrfs_run_delayed_iputs(info);
1089
1090 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1091 wake_up_process(info->transaction_kthread);
1092 if (TRANS_ABORTED(trans))
1093 ret = trans->aborted;
1094 else
1095 ret = -EROFS;
1096 }
1097
1098 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1099 return ret;
1100}
1101
1102int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1103{
1104 return __btrfs_end_transaction(trans, 0);
1105}
1106
1107int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1108{
1109 return __btrfs_end_transaction(trans, 1);
1110}
1111
1112/*
1113 * when btree blocks are allocated, they have some corresponding bits set for
1114 * them in one of two extent_io trees. This is used to make sure all of
1115 * those extents are sent to disk but does not wait on them
1116 */
1117int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1118 struct extent_io_tree *dirty_pages, int mark)
1119{
1120 int ret = 0;
1121 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1122 struct extent_state *cached_state = NULL;
1123 u64 start = 0;
1124 u64 end;
1125
1126 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1127 mark, &cached_state)) {
1128 bool wait_writeback = false;
1129
1130 ret = convert_extent_bit(dirty_pages, start, end,
1131 EXTENT_NEED_WAIT,
1132 mark, &cached_state);
1133 /*
1134 * convert_extent_bit can return -ENOMEM, which is most of the
1135 * time a temporary error. So when it happens, ignore the error
1136 * and wait for writeback of this range to finish - because we
1137 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1138 * to __btrfs_wait_marked_extents() would not know that
1139 * writeback for this range started and therefore wouldn't
1140 * wait for it to finish - we don't want to commit a
1141 * superblock that points to btree nodes/leafs for which
1142 * writeback hasn't finished yet (and without errors).
1143 * We cleanup any entries left in the io tree when committing
1144 * the transaction (through extent_io_tree_release()).
1145 */
1146 if (ret == -ENOMEM) {
1147 ret = 0;
1148 wait_writeback = true;
1149 }
1150 if (!ret)
1151 ret = filemap_fdatawrite_range(mapping, start, end);
1152 if (!ret && wait_writeback)
1153 ret = filemap_fdatawait_range(mapping, start, end);
1154 free_extent_state(cached_state);
1155 if (ret)
1156 break;
1157 cached_state = NULL;
1158 cond_resched();
1159 start = end + 1;
1160 }
1161 return ret;
1162}
1163
1164/*
1165 * when btree blocks are allocated, they have some corresponding bits set for
1166 * them in one of two extent_io trees. This is used to make sure all of
1167 * those extents are on disk for transaction or log commit. We wait
1168 * on all the pages and clear them from the dirty pages state tree
1169 */
1170static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1171 struct extent_io_tree *dirty_pages)
1172{
1173 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1174 struct extent_state *cached_state = NULL;
1175 u64 start = 0;
1176 u64 end;
1177 int ret = 0;
1178
1179 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1180 EXTENT_NEED_WAIT, &cached_state)) {
1181 /*
1182 * Ignore -ENOMEM errors returned by clear_extent_bit().
1183 * When committing the transaction, we'll remove any entries
1184 * left in the io tree. For a log commit, we don't remove them
1185 * after committing the log because the tree can be accessed
1186 * concurrently - we do it only at transaction commit time when
1187 * it's safe to do it (through extent_io_tree_release()).
1188 */
1189 ret = clear_extent_bit(dirty_pages, start, end,
1190 EXTENT_NEED_WAIT, &cached_state);
1191 if (ret == -ENOMEM)
1192 ret = 0;
1193 if (!ret)
1194 ret = filemap_fdatawait_range(mapping, start, end);
1195 free_extent_state(cached_state);
1196 if (ret)
1197 break;
1198 cached_state = NULL;
1199 cond_resched();
1200 start = end + 1;
1201 }
1202 return ret;
1203}
1204
1205static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1206 struct extent_io_tree *dirty_pages)
1207{
1208 bool errors = false;
1209 int err;
1210
1211 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1212 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1213 errors = true;
1214
1215 if (errors && !err)
1216 err = -EIO;
1217 return err;
1218}
1219
1220int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1221{
1222 struct btrfs_fs_info *fs_info = log_root->fs_info;
1223 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1224 bool errors = false;
1225 int err;
1226
1227 ASSERT(btrfs_root_id(log_root) == BTRFS_TREE_LOG_OBJECTID);
1228
1229 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1230 if ((mark & EXTENT_DIRTY) &&
1231 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1232 errors = true;
1233
1234 if ((mark & EXTENT_NEW) &&
1235 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1236 errors = true;
1237
1238 if (errors && !err)
1239 err = -EIO;
1240 return err;
1241}
1242
1243/*
1244 * When btree blocks are allocated the corresponding extents are marked dirty.
1245 * This function ensures such extents are persisted on disk for transaction or
1246 * log commit.
1247 *
1248 * @trans: transaction whose dirty pages we'd like to write
1249 */
1250static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1251{
1252 int ret;
1253 int ret2;
1254 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1255 struct btrfs_fs_info *fs_info = trans->fs_info;
1256 struct blk_plug plug;
1257
1258 blk_start_plug(&plug);
1259 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1260 blk_finish_plug(&plug);
1261 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1262
1263 extent_io_tree_release(&trans->transaction->dirty_pages);
1264
1265 if (ret)
1266 return ret;
1267 else if (ret2)
1268 return ret2;
1269 else
1270 return 0;
1271}
1272
1273/*
1274 * this is used to update the root pointer in the tree of tree roots.
1275 *
1276 * But, in the case of the extent allocation tree, updating the root
1277 * pointer may allocate blocks which may change the root of the extent
1278 * allocation tree.
1279 *
1280 * So, this loops and repeats and makes sure the cowonly root didn't
1281 * change while the root pointer was being updated in the metadata.
1282 */
1283static int update_cowonly_root(struct btrfs_trans_handle *trans,
1284 struct btrfs_root *root)
1285{
1286 int ret;
1287 u64 old_root_bytenr;
1288 u64 old_root_used;
1289 struct btrfs_fs_info *fs_info = root->fs_info;
1290 struct btrfs_root *tree_root = fs_info->tree_root;
1291
1292 old_root_used = btrfs_root_used(&root->root_item);
1293
1294 while (1) {
1295 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1296 if (old_root_bytenr == root->node->start &&
1297 old_root_used == btrfs_root_used(&root->root_item))
1298 break;
1299
1300 btrfs_set_root_node(&root->root_item, root->node);
1301 ret = btrfs_update_root(trans, tree_root,
1302 &root->root_key,
1303 &root->root_item);
1304 if (ret)
1305 return ret;
1306
1307 old_root_used = btrfs_root_used(&root->root_item);
1308 }
1309
1310 return 0;
1311}
1312
1313/*
1314 * update all the cowonly tree roots on disk
1315 *
1316 * The error handling in this function may not be obvious. Any of the
1317 * failures will cause the file system to go offline. We still need
1318 * to clean up the delayed refs.
1319 */
1320static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1321{
1322 struct btrfs_fs_info *fs_info = trans->fs_info;
1323 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1324 struct list_head *io_bgs = &trans->transaction->io_bgs;
1325 struct list_head *next;
1326 struct extent_buffer *eb;
1327 int ret;
1328
1329 /*
1330 * At this point no one can be using this transaction to modify any tree
1331 * and no one can start another transaction to modify any tree either.
1332 */
1333 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1334
1335 eb = btrfs_lock_root_node(fs_info->tree_root);
1336 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1337 0, &eb, BTRFS_NESTING_COW);
1338 btrfs_tree_unlock(eb);
1339 free_extent_buffer(eb);
1340
1341 if (ret)
1342 return ret;
1343
1344 ret = btrfs_run_dev_stats(trans);
1345 if (ret)
1346 return ret;
1347 ret = btrfs_run_dev_replace(trans);
1348 if (ret)
1349 return ret;
1350 ret = btrfs_run_qgroups(trans);
1351 if (ret)
1352 return ret;
1353
1354 ret = btrfs_setup_space_cache(trans);
1355 if (ret)
1356 return ret;
1357
1358again:
1359 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1360 struct btrfs_root *root;
1361 next = fs_info->dirty_cowonly_roots.next;
1362 list_del_init(next);
1363 root = list_entry(next, struct btrfs_root, dirty_list);
1364 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1365
1366 list_add_tail(&root->dirty_list,
1367 &trans->transaction->switch_commits);
1368 ret = update_cowonly_root(trans, root);
1369 if (ret)
1370 return ret;
1371 }
1372
1373 /* Now flush any delayed refs generated by updating all of the roots */
1374 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1375 if (ret)
1376 return ret;
1377
1378 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1379 ret = btrfs_write_dirty_block_groups(trans);
1380 if (ret)
1381 return ret;
1382
1383 /*
1384 * We're writing the dirty block groups, which could generate
1385 * delayed refs, which could generate more dirty block groups,
1386 * so we want to keep this flushing in this loop to make sure
1387 * everything gets run.
1388 */
1389 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1390 if (ret)
1391 return ret;
1392 }
1393
1394 if (!list_empty(&fs_info->dirty_cowonly_roots))
1395 goto again;
1396
1397 /* Update dev-replace pointer once everything is committed */
1398 fs_info->dev_replace.committed_cursor_left =
1399 fs_info->dev_replace.cursor_left_last_write_of_item;
1400
1401 return 0;
1402}
1403
1404/*
1405 * If we had a pending drop we need to see if there are any others left in our
1406 * dead roots list, and if not clear our bit and wake any waiters.
1407 */
1408void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1409{
1410 /*
1411 * We put the drop in progress roots at the front of the list, so if the
1412 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1413 * up.
1414 */
1415 spin_lock(&fs_info->trans_lock);
1416 if (!list_empty(&fs_info->dead_roots)) {
1417 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1418 struct btrfs_root,
1419 root_list);
1420 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1421 spin_unlock(&fs_info->trans_lock);
1422 return;
1423 }
1424 }
1425 spin_unlock(&fs_info->trans_lock);
1426
1427 btrfs_wake_unfinished_drop(fs_info);
1428}
1429
1430/*
1431 * dead roots are old snapshots that need to be deleted. This allocates
1432 * a dirty root struct and adds it into the list of dead roots that need to
1433 * be deleted
1434 */
1435void btrfs_add_dead_root(struct btrfs_root *root)
1436{
1437 struct btrfs_fs_info *fs_info = root->fs_info;
1438
1439 spin_lock(&fs_info->trans_lock);
1440 if (list_empty(&root->root_list)) {
1441 btrfs_grab_root(root);
1442
1443 /* We want to process the partially complete drops first. */
1444 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1445 list_add(&root->root_list, &fs_info->dead_roots);
1446 else
1447 list_add_tail(&root->root_list, &fs_info->dead_roots);
1448 }
1449 spin_unlock(&fs_info->trans_lock);
1450}
1451
1452/*
1453 * Update each subvolume root and its relocation root, if it exists, in the tree
1454 * of tree roots. Also free log roots if they exist.
1455 */
1456static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1457{
1458 struct btrfs_fs_info *fs_info = trans->fs_info;
1459 struct btrfs_root *gang[8];
1460 int i;
1461 int ret;
1462
1463 /*
1464 * At this point no one can be using this transaction to modify any tree
1465 * and no one can start another transaction to modify any tree either.
1466 */
1467 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1468
1469 spin_lock(&fs_info->fs_roots_radix_lock);
1470 while (1) {
1471 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1472 (void **)gang, 0,
1473 ARRAY_SIZE(gang),
1474 BTRFS_ROOT_TRANS_TAG);
1475 if (ret == 0)
1476 break;
1477 for (i = 0; i < ret; i++) {
1478 struct btrfs_root *root = gang[i];
1479 int ret2;
1480
1481 /*
1482 * At this point we can neither have tasks logging inodes
1483 * from a root nor trying to commit a log tree.
1484 */
1485 ASSERT(atomic_read(&root->log_writers) == 0);
1486 ASSERT(atomic_read(&root->log_commit[0]) == 0);
1487 ASSERT(atomic_read(&root->log_commit[1]) == 0);
1488
1489 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1490 (unsigned long)btrfs_root_id(root),
1491 BTRFS_ROOT_TRANS_TAG);
1492 btrfs_qgroup_free_meta_all_pertrans(root);
1493 spin_unlock(&fs_info->fs_roots_radix_lock);
1494
1495 btrfs_free_log(trans, root);
1496 ret2 = btrfs_update_reloc_root(trans, root);
1497 if (ret2)
1498 return ret2;
1499
1500 /* see comments in should_cow_block() */
1501 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1502 smp_mb__after_atomic();
1503
1504 if (root->commit_root != root->node) {
1505 list_add_tail(&root->dirty_list,
1506 &trans->transaction->switch_commits);
1507 btrfs_set_root_node(&root->root_item,
1508 root->node);
1509 }
1510
1511 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1512 &root->root_key,
1513 &root->root_item);
1514 if (ret2)
1515 return ret2;
1516 spin_lock(&fs_info->fs_roots_radix_lock);
1517 }
1518 }
1519 spin_unlock(&fs_info->fs_roots_radix_lock);
1520 return 0;
1521}
1522
1523/*
1524 * Do all special snapshot related qgroup dirty hack.
1525 *
1526 * Will do all needed qgroup inherit and dirty hack like switch commit
1527 * roots inside one transaction and write all btree into disk, to make
1528 * qgroup works.
1529 */
1530static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1531 struct btrfs_root *src,
1532 struct btrfs_root *parent,
1533 struct btrfs_qgroup_inherit *inherit,
1534 u64 dst_objectid)
1535{
1536 struct btrfs_fs_info *fs_info = src->fs_info;
1537 int ret;
1538
1539 /*
1540 * Save some performance in the case that qgroups are not enabled. If
1541 * this check races with the ioctl, rescan will kick in anyway.
1542 */
1543 if (!btrfs_qgroup_full_accounting(fs_info))
1544 return 0;
1545
1546 /*
1547 * Ensure dirty @src will be committed. Or, after coming
1548 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1549 * recorded root will never be updated again, causing an outdated root
1550 * item.
1551 */
1552 ret = record_root_in_trans(trans, src, 1);
1553 if (ret)
1554 return ret;
1555
1556 /*
1557 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1558 * src root, so we must run the delayed refs here.
1559 *
1560 * However this isn't particularly fool proof, because there's no
1561 * synchronization keeping us from changing the tree after this point
1562 * before we do the qgroup_inherit, or even from making changes while
1563 * we're doing the qgroup_inherit. But that's a problem for the future,
1564 * for now flush the delayed refs to narrow the race window where the
1565 * qgroup counters could end up wrong.
1566 */
1567 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1568 if (ret) {
1569 btrfs_abort_transaction(trans, ret);
1570 return ret;
1571 }
1572
1573 ret = commit_fs_roots(trans);
1574 if (ret)
1575 goto out;
1576 ret = btrfs_qgroup_account_extents(trans);
1577 if (ret < 0)
1578 goto out;
1579
1580 /* Now qgroup are all updated, we can inherit it to new qgroups */
1581 ret = btrfs_qgroup_inherit(trans, btrfs_root_id(src), dst_objectid,
1582 btrfs_root_id(parent), inherit);
1583 if (ret < 0)
1584 goto out;
1585
1586 /*
1587 * Now we do a simplified commit transaction, which will:
1588 * 1) commit all subvolume and extent tree
1589 * To ensure all subvolume and extent tree have a valid
1590 * commit_root to accounting later insert_dir_item()
1591 * 2) write all btree blocks onto disk
1592 * This is to make sure later btree modification will be cowed
1593 * Or commit_root can be populated and cause wrong qgroup numbers
1594 * In this simplified commit, we don't really care about other trees
1595 * like chunk and root tree, as they won't affect qgroup.
1596 * And we don't write super to avoid half committed status.
1597 */
1598 ret = commit_cowonly_roots(trans);
1599 if (ret)
1600 goto out;
1601 switch_commit_roots(trans);
1602 ret = btrfs_write_and_wait_transaction(trans);
1603 if (ret)
1604 btrfs_handle_fs_error(fs_info, ret,
1605 "Error while writing out transaction for qgroup");
1606
1607out:
1608 /*
1609 * Force parent root to be updated, as we recorded it before so its
1610 * last_trans == cur_transid.
1611 * Or it won't be committed again onto disk after later
1612 * insert_dir_item()
1613 */
1614 if (!ret)
1615 ret = record_root_in_trans(trans, parent, 1);
1616 return ret;
1617}
1618
1619/*
1620 * new snapshots need to be created at a very specific time in the
1621 * transaction commit. This does the actual creation.
1622 *
1623 * Note:
1624 * If the error which may affect the commitment of the current transaction
1625 * happens, we should return the error number. If the error which just affect
1626 * the creation of the pending snapshots, just return 0.
1627 */
1628static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1629 struct btrfs_pending_snapshot *pending)
1630{
1631
1632 struct btrfs_fs_info *fs_info = trans->fs_info;
1633 struct btrfs_key key;
1634 struct btrfs_root_item *new_root_item;
1635 struct btrfs_root *tree_root = fs_info->tree_root;
1636 struct btrfs_root *root = pending->root;
1637 struct btrfs_root *parent_root;
1638 struct btrfs_block_rsv *rsv;
1639 struct inode *parent_inode = &pending->dir->vfs_inode;
1640 struct btrfs_path *path;
1641 struct btrfs_dir_item *dir_item;
1642 struct extent_buffer *tmp;
1643 struct extent_buffer *old;
1644 struct timespec64 cur_time;
1645 int ret = 0;
1646 u64 to_reserve = 0;
1647 u64 index = 0;
1648 u64 objectid;
1649 u64 root_flags;
1650 unsigned int nofs_flags;
1651 struct fscrypt_name fname;
1652
1653 ASSERT(pending->path);
1654 path = pending->path;
1655
1656 ASSERT(pending->root_item);
1657 new_root_item = pending->root_item;
1658
1659 /*
1660 * We're inside a transaction and must make sure that any potential
1661 * allocations with GFP_KERNEL in fscrypt won't recurse back to
1662 * filesystem.
1663 */
1664 nofs_flags = memalloc_nofs_save();
1665 pending->error = fscrypt_setup_filename(parent_inode,
1666 &pending->dentry->d_name, 0,
1667 &fname);
1668 memalloc_nofs_restore(nofs_flags);
1669 if (pending->error)
1670 goto free_pending;
1671
1672 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1673 if (pending->error)
1674 goto free_fname;
1675
1676 /*
1677 * Make qgroup to skip current new snapshot's qgroupid, as it is
1678 * accounted by later btrfs_qgroup_inherit().
1679 */
1680 btrfs_set_skip_qgroup(trans, objectid);
1681
1682 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1683
1684 if (to_reserve > 0) {
1685 pending->error = btrfs_block_rsv_add(fs_info,
1686 &pending->block_rsv,
1687 to_reserve,
1688 BTRFS_RESERVE_NO_FLUSH);
1689 if (pending->error)
1690 goto clear_skip_qgroup;
1691 }
1692
1693 key.objectid = objectid;
1694 key.offset = (u64)-1;
1695 key.type = BTRFS_ROOT_ITEM_KEY;
1696
1697 rsv = trans->block_rsv;
1698 trans->block_rsv = &pending->block_rsv;
1699 trans->bytes_reserved = trans->block_rsv->reserved;
1700 trace_btrfs_space_reservation(fs_info, "transaction",
1701 trans->transid,
1702 trans->bytes_reserved, 1);
1703 parent_root = BTRFS_I(parent_inode)->root;
1704 ret = record_root_in_trans(trans, parent_root, 0);
1705 if (ret)
1706 goto fail;
1707 cur_time = current_time(parent_inode);
1708
1709 /*
1710 * insert the directory item
1711 */
1712 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1713 if (ret) {
1714 btrfs_abort_transaction(trans, ret);
1715 goto fail;
1716 }
1717
1718 /* check if there is a file/dir which has the same name. */
1719 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1720 btrfs_ino(BTRFS_I(parent_inode)),
1721 &fname.disk_name, 0);
1722 if (dir_item != NULL && !IS_ERR(dir_item)) {
1723 pending->error = -EEXIST;
1724 goto dir_item_existed;
1725 } else if (IS_ERR(dir_item)) {
1726 ret = PTR_ERR(dir_item);
1727 btrfs_abort_transaction(trans, ret);
1728 goto fail;
1729 }
1730 btrfs_release_path(path);
1731
1732 ret = btrfs_create_qgroup(trans, objectid);
1733 if (ret && ret != -EEXIST) {
1734 btrfs_abort_transaction(trans, ret);
1735 goto fail;
1736 }
1737
1738 /*
1739 * pull in the delayed directory update
1740 * and the delayed inode item
1741 * otherwise we corrupt the FS during
1742 * snapshot
1743 */
1744 ret = btrfs_run_delayed_items(trans);
1745 if (ret) { /* Transaction aborted */
1746 btrfs_abort_transaction(trans, ret);
1747 goto fail;
1748 }
1749
1750 ret = record_root_in_trans(trans, root, 0);
1751 if (ret) {
1752 btrfs_abort_transaction(trans, ret);
1753 goto fail;
1754 }
1755 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1756 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1757 btrfs_check_and_init_root_item(new_root_item);
1758
1759 root_flags = btrfs_root_flags(new_root_item);
1760 if (pending->readonly)
1761 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1762 else
1763 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1764 btrfs_set_root_flags(new_root_item, root_flags);
1765
1766 btrfs_set_root_generation_v2(new_root_item,
1767 trans->transid);
1768 generate_random_guid(new_root_item->uuid);
1769 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1770 BTRFS_UUID_SIZE);
1771 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1772 memset(new_root_item->received_uuid, 0,
1773 sizeof(new_root_item->received_uuid));
1774 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1775 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1776 btrfs_set_root_stransid(new_root_item, 0);
1777 btrfs_set_root_rtransid(new_root_item, 0);
1778 }
1779 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1780 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1781 btrfs_set_root_otransid(new_root_item, trans->transid);
1782
1783 old = btrfs_lock_root_node(root);
1784 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1785 BTRFS_NESTING_COW);
1786 if (ret) {
1787 btrfs_tree_unlock(old);
1788 free_extent_buffer(old);
1789 btrfs_abort_transaction(trans, ret);
1790 goto fail;
1791 }
1792
1793 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1794 /* clean up in any case */
1795 btrfs_tree_unlock(old);
1796 free_extent_buffer(old);
1797 if (ret) {
1798 btrfs_abort_transaction(trans, ret);
1799 goto fail;
1800 }
1801 /* see comments in should_cow_block() */
1802 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1803 smp_wmb();
1804
1805 btrfs_set_root_node(new_root_item, tmp);
1806 /* record when the snapshot was created in key.offset */
1807 key.offset = trans->transid;
1808 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1809 btrfs_tree_unlock(tmp);
1810 free_extent_buffer(tmp);
1811 if (ret) {
1812 btrfs_abort_transaction(trans, ret);
1813 goto fail;
1814 }
1815
1816 /*
1817 * insert root back/forward references
1818 */
1819 ret = btrfs_add_root_ref(trans, objectid,
1820 btrfs_root_id(parent_root),
1821 btrfs_ino(BTRFS_I(parent_inode)), index,
1822 &fname.disk_name);
1823 if (ret) {
1824 btrfs_abort_transaction(trans, ret);
1825 goto fail;
1826 }
1827
1828 key.offset = (u64)-1;
1829 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev);
1830 if (IS_ERR(pending->snap)) {
1831 ret = PTR_ERR(pending->snap);
1832 pending->snap = NULL;
1833 btrfs_abort_transaction(trans, ret);
1834 goto fail;
1835 }
1836
1837 ret = btrfs_reloc_post_snapshot(trans, pending);
1838 if (ret) {
1839 btrfs_abort_transaction(trans, ret);
1840 goto fail;
1841 }
1842
1843 /*
1844 * Do special qgroup accounting for snapshot, as we do some qgroup
1845 * snapshot hack to do fast snapshot.
1846 * To co-operate with that hack, we do hack again.
1847 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1848 */
1849 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL)
1850 ret = qgroup_account_snapshot(trans, root, parent_root,
1851 pending->inherit, objectid);
1852 else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
1853 ret = btrfs_qgroup_inherit(trans, btrfs_root_id(root), objectid,
1854 btrfs_root_id(parent_root), pending->inherit);
1855 if (ret < 0)
1856 goto fail;
1857
1858 ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1859 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1860 index);
1861 if (ret) {
1862 btrfs_abort_transaction(trans, ret);
1863 goto fail;
1864 }
1865
1866 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1867 fname.disk_name.len * 2);
1868 inode_set_mtime_to_ts(parent_inode,
1869 inode_set_ctime_current(parent_inode));
1870 ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode));
1871 if (ret) {
1872 btrfs_abort_transaction(trans, ret);
1873 goto fail;
1874 }
1875 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1876 BTRFS_UUID_KEY_SUBVOL,
1877 objectid);
1878 if (ret) {
1879 btrfs_abort_transaction(trans, ret);
1880 goto fail;
1881 }
1882 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1883 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1884 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1885 objectid);
1886 if (ret && ret != -EEXIST) {
1887 btrfs_abort_transaction(trans, ret);
1888 goto fail;
1889 }
1890 }
1891
1892fail:
1893 pending->error = ret;
1894dir_item_existed:
1895 trans->block_rsv = rsv;
1896 trans->bytes_reserved = 0;
1897clear_skip_qgroup:
1898 btrfs_clear_skip_qgroup(trans);
1899free_fname:
1900 fscrypt_free_filename(&fname);
1901free_pending:
1902 kfree(new_root_item);
1903 pending->root_item = NULL;
1904 btrfs_free_path(path);
1905 pending->path = NULL;
1906
1907 return ret;
1908}
1909
1910/*
1911 * create all the snapshots we've scheduled for creation
1912 */
1913static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1914{
1915 struct btrfs_pending_snapshot *pending, *next;
1916 struct list_head *head = &trans->transaction->pending_snapshots;
1917 int ret = 0;
1918
1919 list_for_each_entry_safe(pending, next, head, list) {
1920 list_del(&pending->list);
1921 ret = create_pending_snapshot(trans, pending);
1922 if (ret)
1923 break;
1924 }
1925 return ret;
1926}
1927
1928static void update_super_roots(struct btrfs_fs_info *fs_info)
1929{
1930 struct btrfs_root_item *root_item;
1931 struct btrfs_super_block *super;
1932
1933 super = fs_info->super_copy;
1934
1935 root_item = &fs_info->chunk_root->root_item;
1936 super->chunk_root = root_item->bytenr;
1937 super->chunk_root_generation = root_item->generation;
1938 super->chunk_root_level = root_item->level;
1939
1940 root_item = &fs_info->tree_root->root_item;
1941 super->root = root_item->bytenr;
1942 super->generation = root_item->generation;
1943 super->root_level = root_item->level;
1944 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1945 super->cache_generation = root_item->generation;
1946 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1947 super->cache_generation = 0;
1948 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1949 super->uuid_tree_generation = root_item->generation;
1950}
1951
1952int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1953{
1954 struct btrfs_transaction *trans;
1955 int ret = 0;
1956
1957 spin_lock(&info->trans_lock);
1958 trans = info->running_transaction;
1959 if (trans)
1960 ret = is_transaction_blocked(trans);
1961 spin_unlock(&info->trans_lock);
1962 return ret;
1963}
1964
1965void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1966{
1967 struct btrfs_fs_info *fs_info = trans->fs_info;
1968 struct btrfs_transaction *cur_trans;
1969
1970 /* Kick the transaction kthread. */
1971 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1972 wake_up_process(fs_info->transaction_kthread);
1973
1974 /* take transaction reference */
1975 cur_trans = trans->transaction;
1976 refcount_inc(&cur_trans->use_count);
1977
1978 btrfs_end_transaction(trans);
1979
1980 /*
1981 * Wait for the current transaction commit to start and block
1982 * subsequent transaction joins
1983 */
1984 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
1985 wait_event(fs_info->transaction_blocked_wait,
1986 cur_trans->state >= TRANS_STATE_COMMIT_START ||
1987 TRANS_ABORTED(cur_trans));
1988 btrfs_put_transaction(cur_trans);
1989}
1990
1991/*
1992 * If there is a running transaction commit it or if it's already committing,
1993 * wait for its commit to complete. Does not start and commit a new transaction
1994 * if there isn't any running.
1995 */
1996int btrfs_commit_current_transaction(struct btrfs_root *root)
1997{
1998 struct btrfs_trans_handle *trans;
1999
2000 trans = btrfs_attach_transaction_barrier(root);
2001 if (IS_ERR(trans)) {
2002 int ret = PTR_ERR(trans);
2003
2004 return (ret == -ENOENT) ? 0 : ret;
2005 }
2006
2007 return btrfs_commit_transaction(trans);
2008}
2009
2010static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
2011{
2012 struct btrfs_fs_info *fs_info = trans->fs_info;
2013 struct btrfs_transaction *cur_trans = trans->transaction;
2014
2015 WARN_ON(refcount_read(&trans->use_count) > 1);
2016
2017 btrfs_abort_transaction(trans, err);
2018
2019 spin_lock(&fs_info->trans_lock);
2020
2021 /*
2022 * If the transaction is removed from the list, it means this
2023 * transaction has been committed successfully, so it is impossible
2024 * to call the cleanup function.
2025 */
2026 BUG_ON(list_empty(&cur_trans->list));
2027
2028 if (cur_trans == fs_info->running_transaction) {
2029 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2030 spin_unlock(&fs_info->trans_lock);
2031
2032 /*
2033 * The thread has already released the lockdep map as reader
2034 * already in btrfs_commit_transaction().
2035 */
2036 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2037 wait_event(cur_trans->writer_wait,
2038 atomic_read(&cur_trans->num_writers) == 1);
2039
2040 spin_lock(&fs_info->trans_lock);
2041 }
2042
2043 /*
2044 * Now that we know no one else is still using the transaction we can
2045 * remove the transaction from the list of transactions. This avoids
2046 * the transaction kthread from cleaning up the transaction while some
2047 * other task is still using it, which could result in a use-after-free
2048 * on things like log trees, as it forces the transaction kthread to
2049 * wait for this transaction to be cleaned up by us.
2050 */
2051 list_del_init(&cur_trans->list);
2052
2053 spin_unlock(&fs_info->trans_lock);
2054
2055 btrfs_cleanup_one_transaction(trans->transaction);
2056
2057 spin_lock(&fs_info->trans_lock);
2058 if (cur_trans == fs_info->running_transaction)
2059 fs_info->running_transaction = NULL;
2060 spin_unlock(&fs_info->trans_lock);
2061
2062 if (trans->type & __TRANS_FREEZABLE)
2063 sb_end_intwrite(fs_info->sb);
2064 btrfs_put_transaction(cur_trans);
2065 btrfs_put_transaction(cur_trans);
2066
2067 trace_btrfs_transaction_commit(fs_info);
2068
2069 if (current->journal_info == trans)
2070 current->journal_info = NULL;
2071
2072 /*
2073 * If relocation is running, we can't cancel scrub because that will
2074 * result in a deadlock. Before relocating a block group, relocation
2075 * pauses scrub, then starts and commits a transaction before unpausing
2076 * scrub. If the transaction commit is being done by the relocation
2077 * task or triggered by another task and the relocation task is waiting
2078 * for the commit, and we end up here due to an error in the commit
2079 * path, then calling btrfs_scrub_cancel() will deadlock, as we are
2080 * asking for scrub to stop while having it asked to be paused higher
2081 * above in relocation code.
2082 */
2083 if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
2084 btrfs_scrub_cancel(fs_info);
2085
2086 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2087}
2088
2089/*
2090 * Release reserved delayed ref space of all pending block groups of the
2091 * transaction and remove them from the list
2092 */
2093static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2094{
2095 struct btrfs_fs_info *fs_info = trans->fs_info;
2096 struct btrfs_block_group *block_group, *tmp;
2097
2098 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2099 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2100 list_del_init(&block_group->bg_list);
2101 }
2102}
2103
2104static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2105{
2106 /*
2107 * We use try_to_writeback_inodes_sb() here because if we used
2108 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2109 * Currently are holding the fs freeze lock, if we do an async flush
2110 * we'll do btrfs_join_transaction() and deadlock because we need to
2111 * wait for the fs freeze lock. Using the direct flushing we benefit
2112 * from already being in a transaction and our join_transaction doesn't
2113 * have to re-take the fs freeze lock.
2114 *
2115 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2116 * if it can read lock sb->s_umount. It will always be able to lock it,
2117 * except when the filesystem is being unmounted or being frozen, but in
2118 * those cases sync_filesystem() is called, which results in calling
2119 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2120 * Note that we don't call writeback_inodes_sb() directly, because it
2121 * will emit a warning if sb->s_umount is not locked.
2122 */
2123 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2124 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2125 return 0;
2126}
2127
2128static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2129{
2130 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2131 btrfs_wait_ordered_roots(fs_info, U64_MAX, NULL);
2132}
2133
2134/*
2135 * Add a pending snapshot associated with the given transaction handle to the
2136 * respective handle. This must be called after the transaction commit started
2137 * and while holding fs_info->trans_lock.
2138 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2139 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2140 * returns an error.
2141 */
2142static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2143{
2144 struct btrfs_transaction *cur_trans = trans->transaction;
2145
2146 if (!trans->pending_snapshot)
2147 return;
2148
2149 lockdep_assert_held(&trans->fs_info->trans_lock);
2150 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP);
2151
2152 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2153}
2154
2155static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
2156{
2157 fs_info->commit_stats.commit_count++;
2158 fs_info->commit_stats.last_commit_dur = interval;
2159 fs_info->commit_stats.max_commit_dur =
2160 max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2161 fs_info->commit_stats.total_commit_dur += interval;
2162}
2163
2164int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2165{
2166 struct btrfs_fs_info *fs_info = trans->fs_info;
2167 struct btrfs_transaction *cur_trans = trans->transaction;
2168 struct btrfs_transaction *prev_trans = NULL;
2169 int ret;
2170 ktime_t start_time;
2171 ktime_t interval;
2172
2173 ASSERT(refcount_read(&trans->use_count) == 1);
2174 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2175
2176 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2177
2178 /* Stop the commit early if ->aborted is set */
2179 if (TRANS_ABORTED(cur_trans)) {
2180 ret = cur_trans->aborted;
2181 goto lockdep_trans_commit_start_release;
2182 }
2183
2184 btrfs_trans_release_metadata(trans);
2185 trans->block_rsv = NULL;
2186
2187 /*
2188 * We only want one transaction commit doing the flushing so we do not
2189 * waste a bunch of time on lock contention on the extent root node.
2190 */
2191 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2192 &cur_trans->delayed_refs.flags)) {
2193 /*
2194 * Make a pass through all the delayed refs we have so far.
2195 * Any running threads may add more while we are here.
2196 */
2197 ret = btrfs_run_delayed_refs(trans, 0);
2198 if (ret)
2199 goto lockdep_trans_commit_start_release;
2200 }
2201
2202 btrfs_create_pending_block_groups(trans);
2203
2204 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2205 int run_it = 0;
2206
2207 /* this mutex is also taken before trying to set
2208 * block groups readonly. We need to make sure
2209 * that nobody has set a block group readonly
2210 * after a extents from that block group have been
2211 * allocated for cache files. btrfs_set_block_group_ro
2212 * will wait for the transaction to commit if it
2213 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2214 *
2215 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2216 * only one process starts all the block group IO. It wouldn't
2217 * hurt to have more than one go through, but there's no
2218 * real advantage to it either.
2219 */
2220 mutex_lock(&fs_info->ro_block_group_mutex);
2221 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2222 &cur_trans->flags))
2223 run_it = 1;
2224 mutex_unlock(&fs_info->ro_block_group_mutex);
2225
2226 if (run_it) {
2227 ret = btrfs_start_dirty_block_groups(trans);
2228 if (ret)
2229 goto lockdep_trans_commit_start_release;
2230 }
2231 }
2232
2233 spin_lock(&fs_info->trans_lock);
2234 if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) {
2235 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2236
2237 add_pending_snapshot(trans);
2238
2239 spin_unlock(&fs_info->trans_lock);
2240 refcount_inc(&cur_trans->use_count);
2241
2242 if (trans->in_fsync)
2243 want_state = TRANS_STATE_SUPER_COMMITTED;
2244
2245 btrfs_trans_state_lockdep_release(fs_info,
2246 BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2247 ret = btrfs_end_transaction(trans);
2248 wait_for_commit(cur_trans, want_state);
2249
2250 if (TRANS_ABORTED(cur_trans))
2251 ret = cur_trans->aborted;
2252
2253 btrfs_put_transaction(cur_trans);
2254
2255 return ret;
2256 }
2257
2258 cur_trans->state = TRANS_STATE_COMMIT_PREP;
2259 wake_up(&fs_info->transaction_blocked_wait);
2260 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2261
2262 if (cur_trans->list.prev != &fs_info->trans_list) {
2263 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2264
2265 if (trans->in_fsync)
2266 want_state = TRANS_STATE_SUPER_COMMITTED;
2267
2268 prev_trans = list_entry(cur_trans->list.prev,
2269 struct btrfs_transaction, list);
2270 if (prev_trans->state < want_state) {
2271 refcount_inc(&prev_trans->use_count);
2272 spin_unlock(&fs_info->trans_lock);
2273
2274 wait_for_commit(prev_trans, want_state);
2275
2276 ret = READ_ONCE(prev_trans->aborted);
2277
2278 btrfs_put_transaction(prev_trans);
2279 if (ret)
2280 goto lockdep_release;
2281 spin_lock(&fs_info->trans_lock);
2282 }
2283 } else {
2284 /*
2285 * The previous transaction was aborted and was already removed
2286 * from the list of transactions at fs_info->trans_list. So we
2287 * abort to prevent writing a new superblock that reflects a
2288 * corrupt state (pointing to trees with unwritten nodes/leafs).
2289 */
2290 if (BTRFS_FS_ERROR(fs_info)) {
2291 spin_unlock(&fs_info->trans_lock);
2292 ret = -EROFS;
2293 goto lockdep_release;
2294 }
2295 }
2296
2297 cur_trans->state = TRANS_STATE_COMMIT_START;
2298 wake_up(&fs_info->transaction_blocked_wait);
2299 spin_unlock(&fs_info->trans_lock);
2300
2301 /*
2302 * Get the time spent on the work done by the commit thread and not
2303 * the time spent waiting on a previous commit
2304 */
2305 start_time = ktime_get_ns();
2306
2307 extwriter_counter_dec(cur_trans, trans->type);
2308
2309 ret = btrfs_start_delalloc_flush(fs_info);
2310 if (ret)
2311 goto lockdep_release;
2312
2313 ret = btrfs_run_delayed_items(trans);
2314 if (ret)
2315 goto lockdep_release;
2316
2317 /*
2318 * The thread has started/joined the transaction thus it holds the
2319 * lockdep map as a reader. It has to release it before acquiring the
2320 * lockdep map as a writer.
2321 */
2322 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2323 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2324 wait_event(cur_trans->writer_wait,
2325 extwriter_counter_read(cur_trans) == 0);
2326
2327 /* some pending stuffs might be added after the previous flush. */
2328 ret = btrfs_run_delayed_items(trans);
2329 if (ret) {
2330 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2331 goto cleanup_transaction;
2332 }
2333
2334 btrfs_wait_delalloc_flush(fs_info);
2335
2336 /*
2337 * Wait for all ordered extents started by a fast fsync that joined this
2338 * transaction. Otherwise if this transaction commits before the ordered
2339 * extents complete we lose logged data after a power failure.
2340 */
2341 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2342 wait_event(cur_trans->pending_wait,
2343 atomic_read(&cur_trans->pending_ordered) == 0);
2344
2345 btrfs_scrub_pause(fs_info);
2346 /*
2347 * Ok now we need to make sure to block out any other joins while we
2348 * commit the transaction. We could have started a join before setting
2349 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2350 */
2351 spin_lock(&fs_info->trans_lock);
2352 add_pending_snapshot(trans);
2353 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2354 spin_unlock(&fs_info->trans_lock);
2355
2356 /*
2357 * The thread has started/joined the transaction thus it holds the
2358 * lockdep map as a reader. It has to release it before acquiring the
2359 * lockdep map as a writer.
2360 */
2361 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2362 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2363 wait_event(cur_trans->writer_wait,
2364 atomic_read(&cur_trans->num_writers) == 1);
2365
2366 /*
2367 * Make lockdep happy by acquiring the state locks after
2368 * btrfs_trans_num_writers is released. If we acquired the state locks
2369 * before releasing the btrfs_trans_num_writers lock then lockdep would
2370 * complain because we did not follow the reverse order unlocking rule.
2371 */
2372 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2373 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2374 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2375
2376 /*
2377 * We've started the commit, clear the flag in case we were triggered to
2378 * do an async commit but somebody else started before the transaction
2379 * kthread could do the work.
2380 */
2381 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2382
2383 if (TRANS_ABORTED(cur_trans)) {
2384 ret = cur_trans->aborted;
2385 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2386 goto scrub_continue;
2387 }
2388 /*
2389 * the reloc mutex makes sure that we stop
2390 * the balancing code from coming in and moving
2391 * extents around in the middle of the commit
2392 */
2393 mutex_lock(&fs_info->reloc_mutex);
2394
2395 /*
2396 * We needn't worry about the delayed items because we will
2397 * deal with them in create_pending_snapshot(), which is the
2398 * core function of the snapshot creation.
2399 */
2400 ret = create_pending_snapshots(trans);
2401 if (ret)
2402 goto unlock_reloc;
2403
2404 /*
2405 * We insert the dir indexes of the snapshots and update the inode
2406 * of the snapshots' parents after the snapshot creation, so there
2407 * are some delayed items which are not dealt with. Now deal with
2408 * them.
2409 *
2410 * We needn't worry that this operation will corrupt the snapshots,
2411 * because all the tree which are snapshoted will be forced to COW
2412 * the nodes and leaves.
2413 */
2414 ret = btrfs_run_delayed_items(trans);
2415 if (ret)
2416 goto unlock_reloc;
2417
2418 ret = btrfs_run_delayed_refs(trans, U64_MAX);
2419 if (ret)
2420 goto unlock_reloc;
2421
2422 /*
2423 * make sure none of the code above managed to slip in a
2424 * delayed item
2425 */
2426 btrfs_assert_delayed_root_empty(fs_info);
2427
2428 WARN_ON(cur_trans != trans->transaction);
2429
2430 ret = commit_fs_roots(trans);
2431 if (ret)
2432 goto unlock_reloc;
2433
2434 /* commit_fs_roots gets rid of all the tree log roots, it is now
2435 * safe to free the root of tree log roots
2436 */
2437 btrfs_free_log_root_tree(trans, fs_info);
2438
2439 /*
2440 * Since fs roots are all committed, we can get a quite accurate
2441 * new_roots. So let's do quota accounting.
2442 */
2443 ret = btrfs_qgroup_account_extents(trans);
2444 if (ret < 0)
2445 goto unlock_reloc;
2446
2447 ret = commit_cowonly_roots(trans);
2448 if (ret)
2449 goto unlock_reloc;
2450
2451 /*
2452 * The tasks which save the space cache and inode cache may also
2453 * update ->aborted, check it.
2454 */
2455 if (TRANS_ABORTED(cur_trans)) {
2456 ret = cur_trans->aborted;
2457 goto unlock_reloc;
2458 }
2459
2460 cur_trans = fs_info->running_transaction;
2461
2462 btrfs_set_root_node(&fs_info->tree_root->root_item,
2463 fs_info->tree_root->node);
2464 list_add_tail(&fs_info->tree_root->dirty_list,
2465 &cur_trans->switch_commits);
2466
2467 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2468 fs_info->chunk_root->node);
2469 list_add_tail(&fs_info->chunk_root->dirty_list,
2470 &cur_trans->switch_commits);
2471
2472 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2473 btrfs_set_root_node(&fs_info->block_group_root->root_item,
2474 fs_info->block_group_root->node);
2475 list_add_tail(&fs_info->block_group_root->dirty_list,
2476 &cur_trans->switch_commits);
2477 }
2478
2479 switch_commit_roots(trans);
2480
2481 ASSERT(list_empty(&cur_trans->dirty_bgs));
2482 ASSERT(list_empty(&cur_trans->io_bgs));
2483 update_super_roots(fs_info);
2484
2485 btrfs_set_super_log_root(fs_info->super_copy, 0);
2486 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2487 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2488 sizeof(*fs_info->super_copy));
2489
2490 btrfs_commit_device_sizes(cur_trans);
2491
2492 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2493 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2494
2495 btrfs_trans_release_chunk_metadata(trans);
2496
2497 /*
2498 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2499 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2500 * make sure that before we commit our superblock, no other task can
2501 * start a new transaction and commit a log tree before we commit our
2502 * superblock. Anyone trying to commit a log tree locks this mutex before
2503 * writing its superblock.
2504 */
2505 mutex_lock(&fs_info->tree_log_mutex);
2506
2507 spin_lock(&fs_info->trans_lock);
2508 cur_trans->state = TRANS_STATE_UNBLOCKED;
2509 fs_info->running_transaction = NULL;
2510 spin_unlock(&fs_info->trans_lock);
2511 mutex_unlock(&fs_info->reloc_mutex);
2512
2513 wake_up(&fs_info->transaction_wait);
2514 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2515
2516 /* If we have features changed, wake up the cleaner to update sysfs. */
2517 if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
2518 fs_info->cleaner_kthread)
2519 wake_up_process(fs_info->cleaner_kthread);
2520
2521 ret = btrfs_write_and_wait_transaction(trans);
2522 if (ret) {
2523 btrfs_handle_fs_error(fs_info, ret,
2524 "Error while writing out transaction");
2525 mutex_unlock(&fs_info->tree_log_mutex);
2526 goto scrub_continue;
2527 }
2528
2529 ret = write_all_supers(fs_info, 0);
2530 /*
2531 * the super is written, we can safely allow the tree-loggers
2532 * to go about their business
2533 */
2534 mutex_unlock(&fs_info->tree_log_mutex);
2535 if (ret)
2536 goto scrub_continue;
2537
2538 /*
2539 * We needn't acquire the lock here because there is no other task
2540 * which can change it.
2541 */
2542 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2543 wake_up(&cur_trans->commit_wait);
2544 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2545
2546 btrfs_finish_extent_commit(trans);
2547
2548 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2549 btrfs_clear_space_info_full(fs_info);
2550
2551 btrfs_set_last_trans_committed(fs_info, cur_trans->transid);
2552 /*
2553 * We needn't acquire the lock here because there is no other task
2554 * which can change it.
2555 */
2556 cur_trans->state = TRANS_STATE_COMPLETED;
2557 wake_up(&cur_trans->commit_wait);
2558 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2559
2560 spin_lock(&fs_info->trans_lock);
2561 list_del_init(&cur_trans->list);
2562 spin_unlock(&fs_info->trans_lock);
2563
2564 btrfs_put_transaction(cur_trans);
2565 btrfs_put_transaction(cur_trans);
2566
2567 if (trans->type & __TRANS_FREEZABLE)
2568 sb_end_intwrite(fs_info->sb);
2569
2570 trace_btrfs_transaction_commit(fs_info);
2571
2572 interval = ktime_get_ns() - start_time;
2573
2574 btrfs_scrub_continue(fs_info);
2575
2576 if (current->journal_info == trans)
2577 current->journal_info = NULL;
2578
2579 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2580
2581 update_commit_stats(fs_info, interval);
2582
2583 return ret;
2584
2585unlock_reloc:
2586 mutex_unlock(&fs_info->reloc_mutex);
2587 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2588scrub_continue:
2589 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2590 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2591 btrfs_scrub_continue(fs_info);
2592cleanup_transaction:
2593 btrfs_trans_release_metadata(trans);
2594 btrfs_cleanup_pending_block_groups(trans);
2595 btrfs_trans_release_chunk_metadata(trans);
2596 trans->block_rsv = NULL;
2597 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2598 if (current->journal_info == trans)
2599 current->journal_info = NULL;
2600 cleanup_transaction(trans, ret);
2601
2602 return ret;
2603
2604lockdep_release:
2605 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2606 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2607 goto cleanup_transaction;
2608
2609lockdep_trans_commit_start_release:
2610 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2611 btrfs_end_transaction(trans);
2612 return ret;
2613}
2614
2615/*
2616 * return < 0 if error
2617 * 0 if there are no more dead_roots at the time of call
2618 * 1 there are more to be processed, call me again
2619 *
2620 * The return value indicates there are certainly more snapshots to delete, but
2621 * if there comes a new one during processing, it may return 0. We don't mind,
2622 * because btrfs_commit_super will poke cleaner thread and it will process it a
2623 * few seconds later.
2624 */
2625int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2626{
2627 struct btrfs_root *root;
2628 int ret;
2629
2630 spin_lock(&fs_info->trans_lock);
2631 if (list_empty(&fs_info->dead_roots)) {
2632 spin_unlock(&fs_info->trans_lock);
2633 return 0;
2634 }
2635 root = list_first_entry(&fs_info->dead_roots,
2636 struct btrfs_root, root_list);
2637 list_del_init(&root->root_list);
2638 spin_unlock(&fs_info->trans_lock);
2639
2640 btrfs_debug(fs_info, "cleaner removing %llu", btrfs_root_id(root));
2641
2642 btrfs_kill_all_delayed_nodes(root);
2643
2644 if (btrfs_header_backref_rev(root->node) <
2645 BTRFS_MIXED_BACKREF_REV)
2646 ret = btrfs_drop_snapshot(root, 0, 0);
2647 else
2648 ret = btrfs_drop_snapshot(root, 1, 0);
2649
2650 btrfs_put_root(root);
2651 return (ret < 0) ? 0 : 1;
2652}
2653
2654/*
2655 * We only mark the transaction aborted and then set the file system read-only.
2656 * This will prevent new transactions from starting or trying to join this
2657 * one.
2658 *
2659 * This means that error recovery at the call site is limited to freeing
2660 * any local memory allocations and passing the error code up without
2661 * further cleanup. The transaction should complete as it normally would
2662 * in the call path but will return -EIO.
2663 *
2664 * We'll complete the cleanup in btrfs_end_transaction and
2665 * btrfs_commit_transaction.
2666 */
2667void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
2668 const char *function,
2669 unsigned int line, int error, bool first_hit)
2670{
2671 struct btrfs_fs_info *fs_info = trans->fs_info;
2672
2673 WRITE_ONCE(trans->aborted, error);
2674 WRITE_ONCE(trans->transaction->aborted, error);
2675 if (first_hit && error == -ENOSPC)
2676 btrfs_dump_space_info_for_trans_abort(fs_info);
2677 /* Wake up anybody who may be waiting on this transaction */
2678 wake_up(&fs_info->transaction_wait);
2679 wake_up(&fs_info->transaction_blocked_wait);
2680 __btrfs_handle_fs_error(fs_info, function, line, error, NULL);
2681}
2682
2683int __init btrfs_transaction_init(void)
2684{
2685 btrfs_trans_handle_cachep = KMEM_CACHE(btrfs_trans_handle, SLAB_TEMPORARY);
2686 if (!btrfs_trans_handle_cachep)
2687 return -ENOMEM;
2688 return 0;
2689}
2690
2691void __cold btrfs_transaction_exit(void)
2692{
2693 kmem_cache_destroy(btrfs_trans_handle_cachep);
2694}
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/*
41 * Transaction states and transitions
42 *
43 * No running transaction (fs tree blocks are not modified)
44 * |
45 * | To next stage:
46 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
47 * V
48 * Transaction N [[TRANS_STATE_RUNNING]]
49 * |
50 * | New trans handles can be attached to transaction N by calling all
51 * | start_transaction() variants.
52 * |
53 * | To next stage:
54 * | Call btrfs_commit_transaction() on any trans handle attached to
55 * | transaction N
56 * V
57 * Transaction N [[TRANS_STATE_COMMIT_PREP]]
58 * |
59 * | If there are simultaneous calls to btrfs_commit_transaction() one will win
60 * | the race and the rest will wait for the winner to commit the transaction.
61 * |
62 * | The winner will wait for previous running transaction to completely finish
63 * | if there is one.
64 * |
65 * Transaction N [[TRANS_STATE_COMMIT_START]]
66 * |
67 * | Then one of the following happens:
68 * | - Wait for all other trans handle holders to release.
69 * | The btrfs_commit_transaction() caller will do the commit work.
70 * | - Wait for current transaction to be committed by others.
71 * | Other btrfs_commit_transaction() caller will do the commit work.
72 * |
73 * | At this stage, only btrfs_join_transaction*() variants can attach
74 * | to this running transaction.
75 * | All other variants will wait for current one to finish and attach to
76 * | transaction N+1.
77 * |
78 * | To next stage:
79 * | Caller is chosen to commit transaction N, and all other trans handle
80 * | haven been released.
81 * V
82 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
83 * |
84 * | The heavy lifting transaction work is started.
85 * | From running delayed refs (modifying extent tree) to creating pending
86 * | snapshots, running qgroups.
87 * | In short, modify supporting trees to reflect modifications of subvolume
88 * | trees.
89 * |
90 * | At this stage, all start_transaction() calls will wait for this
91 * | transaction to finish and attach to transaction N+1.
92 * |
93 * | To next stage:
94 * | Until all supporting trees are updated.
95 * V
96 * Transaction N [[TRANS_STATE_UNBLOCKED]]
97 * | Transaction N+1
98 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
99 * | need to write them back to disk and update |
100 * | super blocks. |
101 * | |
102 * | At this stage, new transaction is allowed to |
103 * | start. |
104 * | All new start_transaction() calls will be |
105 * | attached to transid N+1. |
106 * | |
107 * | To next stage: |
108 * | Until all tree blocks are super blocks are |
109 * | written to block devices |
110 * V |
111 * Transaction N [[TRANS_STATE_COMPLETED]] V
112 * All tree blocks and super blocks are written. Transaction N+1
113 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
114 * data structures will be cleaned up. | Life goes on
115 */
116static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
117 [TRANS_STATE_RUNNING] = 0U,
118 [TRANS_STATE_COMMIT_PREP] = 0U,
119 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
120 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
121 __TRANS_ATTACH |
122 __TRANS_JOIN |
123 __TRANS_JOIN_NOSTART),
124 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
125 __TRANS_ATTACH |
126 __TRANS_JOIN |
127 __TRANS_JOIN_NOLOCK |
128 __TRANS_JOIN_NOSTART),
129 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
130 __TRANS_ATTACH |
131 __TRANS_JOIN |
132 __TRANS_JOIN_NOLOCK |
133 __TRANS_JOIN_NOSTART),
134 [TRANS_STATE_COMPLETED] = (__TRANS_START |
135 __TRANS_ATTACH |
136 __TRANS_JOIN |
137 __TRANS_JOIN_NOLOCK |
138 __TRANS_JOIN_NOSTART),
139};
140
141void btrfs_put_transaction(struct btrfs_transaction *transaction)
142{
143 WARN_ON(refcount_read(&transaction->use_count) == 0);
144 if (refcount_dec_and_test(&transaction->use_count)) {
145 BUG_ON(!list_empty(&transaction->list));
146 WARN_ON(!RB_EMPTY_ROOT(
147 &transaction->delayed_refs.href_root.rb_root));
148 WARN_ON(!RB_EMPTY_ROOT(
149 &transaction->delayed_refs.dirty_extent_root));
150 if (transaction->delayed_refs.pending_csums)
151 btrfs_err(transaction->fs_info,
152 "pending csums is %llu",
153 transaction->delayed_refs.pending_csums);
154 /*
155 * If any block groups are found in ->deleted_bgs then it's
156 * because the transaction was aborted and a commit did not
157 * happen (things failed before writing the new superblock
158 * and calling btrfs_finish_extent_commit()), so we can not
159 * discard the physical locations of the block groups.
160 */
161 while (!list_empty(&transaction->deleted_bgs)) {
162 struct btrfs_block_group *cache;
163
164 cache = list_first_entry(&transaction->deleted_bgs,
165 struct btrfs_block_group,
166 bg_list);
167 list_del_init(&cache->bg_list);
168 btrfs_unfreeze_block_group(cache);
169 btrfs_put_block_group(cache);
170 }
171 WARN_ON(!list_empty(&transaction->dev_update_list));
172 kfree(transaction);
173 }
174}
175
176static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
177{
178 struct btrfs_transaction *cur_trans = trans->transaction;
179 struct btrfs_fs_info *fs_info = trans->fs_info;
180 struct btrfs_root *root, *tmp;
181
182 /*
183 * At this point no one can be using this transaction to modify any tree
184 * and no one can start another transaction to modify any tree either.
185 */
186 ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
187
188 down_write(&fs_info->commit_root_sem);
189
190 if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
191 fs_info->last_reloc_trans = trans->transid;
192
193 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
194 dirty_list) {
195 list_del_init(&root->dirty_list);
196 free_extent_buffer(root->commit_root);
197 root->commit_root = btrfs_root_node(root);
198 extent_io_tree_release(&root->dirty_log_pages);
199 btrfs_qgroup_clean_swapped_blocks(root);
200 }
201
202 /* We can free old roots now. */
203 spin_lock(&cur_trans->dropped_roots_lock);
204 while (!list_empty(&cur_trans->dropped_roots)) {
205 root = list_first_entry(&cur_trans->dropped_roots,
206 struct btrfs_root, root_list);
207 list_del_init(&root->root_list);
208 spin_unlock(&cur_trans->dropped_roots_lock);
209 btrfs_free_log(trans, root);
210 btrfs_drop_and_free_fs_root(fs_info, root);
211 spin_lock(&cur_trans->dropped_roots_lock);
212 }
213 spin_unlock(&cur_trans->dropped_roots_lock);
214
215 up_write(&fs_info->commit_root_sem);
216}
217
218static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
219 unsigned int type)
220{
221 if (type & TRANS_EXTWRITERS)
222 atomic_inc(&trans->num_extwriters);
223}
224
225static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
226 unsigned int type)
227{
228 if (type & TRANS_EXTWRITERS)
229 atomic_dec(&trans->num_extwriters);
230}
231
232static inline void extwriter_counter_init(struct btrfs_transaction *trans,
233 unsigned int type)
234{
235 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
236}
237
238static inline int extwriter_counter_read(struct btrfs_transaction *trans)
239{
240 return atomic_read(&trans->num_extwriters);
241}
242
243/*
244 * To be called after doing the chunk btree updates right after allocating a new
245 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
246 * chunk after all chunk btree updates and after finishing the second phase of
247 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
248 * group had its chunk item insertion delayed to the second phase.
249 */
250void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
251{
252 struct btrfs_fs_info *fs_info = trans->fs_info;
253
254 if (!trans->chunk_bytes_reserved)
255 return;
256
257 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
258 trans->chunk_bytes_reserved, NULL);
259 trans->chunk_bytes_reserved = 0;
260}
261
262/*
263 * either allocate a new transaction or hop into the existing one
264 */
265static noinline int join_transaction(struct btrfs_fs_info *fs_info,
266 unsigned int type)
267{
268 struct btrfs_transaction *cur_trans;
269
270 spin_lock(&fs_info->trans_lock);
271loop:
272 /* The file system has been taken offline. No new transactions. */
273 if (BTRFS_FS_ERROR(fs_info)) {
274 spin_unlock(&fs_info->trans_lock);
275 return -EROFS;
276 }
277
278 cur_trans = fs_info->running_transaction;
279 if (cur_trans) {
280 if (TRANS_ABORTED(cur_trans)) {
281 spin_unlock(&fs_info->trans_lock);
282 return cur_trans->aborted;
283 }
284 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
285 spin_unlock(&fs_info->trans_lock);
286 return -EBUSY;
287 }
288 refcount_inc(&cur_trans->use_count);
289 atomic_inc(&cur_trans->num_writers);
290 extwriter_counter_inc(cur_trans, type);
291 spin_unlock(&fs_info->trans_lock);
292 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
293 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
294 return 0;
295 }
296 spin_unlock(&fs_info->trans_lock);
297
298 /*
299 * If we are ATTACH or TRANS_JOIN_NOSTART, we just want to catch the
300 * current transaction, and commit it. If there is no transaction, just
301 * return ENOENT.
302 */
303 if (type == TRANS_ATTACH || type == TRANS_JOIN_NOSTART)
304 return -ENOENT;
305
306 /*
307 * JOIN_NOLOCK only happens during the transaction commit, so
308 * it is impossible that ->running_transaction is NULL
309 */
310 BUG_ON(type == TRANS_JOIN_NOLOCK);
311
312 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
313 if (!cur_trans)
314 return -ENOMEM;
315
316 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
317 btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
318
319 spin_lock(&fs_info->trans_lock);
320 if (fs_info->running_transaction) {
321 /*
322 * someone started a transaction after we unlocked. Make sure
323 * to redo the checks above
324 */
325 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
326 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
327 kfree(cur_trans);
328 goto loop;
329 } else if (BTRFS_FS_ERROR(fs_info)) {
330 spin_unlock(&fs_info->trans_lock);
331 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
332 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
333 kfree(cur_trans);
334 return -EROFS;
335 }
336
337 cur_trans->fs_info = fs_info;
338 atomic_set(&cur_trans->pending_ordered, 0);
339 init_waitqueue_head(&cur_trans->pending_wait);
340 atomic_set(&cur_trans->num_writers, 1);
341 extwriter_counter_init(cur_trans, type);
342 init_waitqueue_head(&cur_trans->writer_wait);
343 init_waitqueue_head(&cur_trans->commit_wait);
344 cur_trans->state = TRANS_STATE_RUNNING;
345 /*
346 * One for this trans handle, one so it will live on until we
347 * commit the transaction.
348 */
349 refcount_set(&cur_trans->use_count, 2);
350 cur_trans->flags = 0;
351 cur_trans->start_time = ktime_get_seconds();
352
353 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
354
355 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
356 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
357 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
358
359 /*
360 * although the tree mod log is per file system and not per transaction,
361 * the log must never go across transaction boundaries.
362 */
363 smp_mb();
364 if (!list_empty(&fs_info->tree_mod_seq_list))
365 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
366 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
367 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
368 atomic64_set(&fs_info->tree_mod_seq, 0);
369
370 spin_lock_init(&cur_trans->delayed_refs.lock);
371
372 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
373 INIT_LIST_HEAD(&cur_trans->dev_update_list);
374 INIT_LIST_HEAD(&cur_trans->switch_commits);
375 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
376 INIT_LIST_HEAD(&cur_trans->io_bgs);
377 INIT_LIST_HEAD(&cur_trans->dropped_roots);
378 mutex_init(&cur_trans->cache_write_mutex);
379 spin_lock_init(&cur_trans->dirty_bgs_lock);
380 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
381 spin_lock_init(&cur_trans->dropped_roots_lock);
382 list_add_tail(&cur_trans->list, &fs_info->trans_list);
383 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
384 IO_TREE_TRANS_DIRTY_PAGES);
385 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
386 IO_TREE_FS_PINNED_EXTENTS);
387 btrfs_set_fs_generation(fs_info, fs_info->generation + 1);
388 cur_trans->transid = fs_info->generation;
389 fs_info->running_transaction = cur_trans;
390 cur_trans->aborted = 0;
391 spin_unlock(&fs_info->trans_lock);
392
393 return 0;
394}
395
396/*
397 * This does all the record keeping required to make sure that a shareable root
398 * is properly recorded in a given transaction. This is required to make sure
399 * the old root from before we joined the transaction is deleted when the
400 * transaction commits.
401 */
402static int record_root_in_trans(struct btrfs_trans_handle *trans,
403 struct btrfs_root *root,
404 int force)
405{
406 struct btrfs_fs_info *fs_info = root->fs_info;
407 int ret = 0;
408
409 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
410 root->last_trans < trans->transid) || force) {
411 WARN_ON(!force && root->commit_root != root->node);
412
413 /*
414 * see below for IN_TRANS_SETUP usage rules
415 * we have the reloc mutex held now, so there
416 * is only one writer in this function
417 */
418 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
419
420 /* make sure readers find IN_TRANS_SETUP before
421 * they find our root->last_trans update
422 */
423 smp_wmb();
424
425 spin_lock(&fs_info->fs_roots_radix_lock);
426 if (root->last_trans == trans->transid && !force) {
427 spin_unlock(&fs_info->fs_roots_radix_lock);
428 return 0;
429 }
430 radix_tree_tag_set(&fs_info->fs_roots_radix,
431 (unsigned long)root->root_key.objectid,
432 BTRFS_ROOT_TRANS_TAG);
433 spin_unlock(&fs_info->fs_roots_radix_lock);
434 root->last_trans = trans->transid;
435
436 /* this is pretty tricky. We don't want to
437 * take the relocation lock in btrfs_record_root_in_trans
438 * unless we're really doing the first setup for this root in
439 * this transaction.
440 *
441 * Normally we'd use root->last_trans as a flag to decide
442 * if we want to take the expensive mutex.
443 *
444 * But, we have to set root->last_trans before we
445 * init the relocation root, otherwise, we trip over warnings
446 * in ctree.c. The solution used here is to flag ourselves
447 * with root IN_TRANS_SETUP. When this is 1, we're still
448 * fixing up the reloc trees and everyone must wait.
449 *
450 * When this is zero, they can trust root->last_trans and fly
451 * through btrfs_record_root_in_trans without having to take the
452 * lock. smp_wmb() makes sure that all the writes above are
453 * done before we pop in the zero below
454 */
455 ret = btrfs_init_reloc_root(trans, root);
456 smp_mb__before_atomic();
457 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
458 }
459 return ret;
460}
461
462
463void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
464 struct btrfs_root *root)
465{
466 struct btrfs_fs_info *fs_info = root->fs_info;
467 struct btrfs_transaction *cur_trans = trans->transaction;
468
469 /* Add ourselves to the transaction dropped list */
470 spin_lock(&cur_trans->dropped_roots_lock);
471 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
472 spin_unlock(&cur_trans->dropped_roots_lock);
473
474 /* Make sure we don't try to update the root at commit time */
475 spin_lock(&fs_info->fs_roots_radix_lock);
476 radix_tree_tag_clear(&fs_info->fs_roots_radix,
477 (unsigned long)root->root_key.objectid,
478 BTRFS_ROOT_TRANS_TAG);
479 spin_unlock(&fs_info->fs_roots_radix_lock);
480}
481
482int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
483 struct btrfs_root *root)
484{
485 struct btrfs_fs_info *fs_info = root->fs_info;
486 int ret;
487
488 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
489 return 0;
490
491 /*
492 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
493 * and barriers
494 */
495 smp_rmb();
496 if (root->last_trans == trans->transid &&
497 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
498 return 0;
499
500 mutex_lock(&fs_info->reloc_mutex);
501 ret = record_root_in_trans(trans, root, 0);
502 mutex_unlock(&fs_info->reloc_mutex);
503
504 return ret;
505}
506
507static inline int is_transaction_blocked(struct btrfs_transaction *trans)
508{
509 return (trans->state >= TRANS_STATE_COMMIT_START &&
510 trans->state < TRANS_STATE_UNBLOCKED &&
511 !TRANS_ABORTED(trans));
512}
513
514/* wait for commit against the current transaction to become unblocked
515 * when this is done, it is safe to start a new transaction, but the current
516 * transaction might not be fully on disk.
517 */
518static void wait_current_trans(struct btrfs_fs_info *fs_info)
519{
520 struct btrfs_transaction *cur_trans;
521
522 spin_lock(&fs_info->trans_lock);
523 cur_trans = fs_info->running_transaction;
524 if (cur_trans && is_transaction_blocked(cur_trans)) {
525 refcount_inc(&cur_trans->use_count);
526 spin_unlock(&fs_info->trans_lock);
527
528 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
529 wait_event(fs_info->transaction_wait,
530 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
531 TRANS_ABORTED(cur_trans));
532 btrfs_put_transaction(cur_trans);
533 } else {
534 spin_unlock(&fs_info->trans_lock);
535 }
536}
537
538static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
539{
540 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
541 return 0;
542
543 if (type == TRANS_START)
544 return 1;
545
546 return 0;
547}
548
549static inline bool need_reserve_reloc_root(struct btrfs_root *root)
550{
551 struct btrfs_fs_info *fs_info = root->fs_info;
552
553 if (!fs_info->reloc_ctl ||
554 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
555 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
556 root->reloc_root)
557 return false;
558
559 return true;
560}
561
562static int btrfs_reserve_trans_metadata(struct btrfs_fs_info *fs_info,
563 enum btrfs_reserve_flush_enum flush,
564 u64 num_bytes,
565 u64 *delayed_refs_bytes)
566{
567 struct btrfs_space_info *si = fs_info->trans_block_rsv.space_info;
568 u64 bytes = num_bytes + *delayed_refs_bytes;
569 int ret;
570
571 /*
572 * We want to reserve all the bytes we may need all at once, so we only
573 * do 1 enospc flushing cycle per transaction start.
574 */
575 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
576
577 /*
578 * If we are an emergency flush, which can steal from the global block
579 * reserve, then attempt to not reserve space for the delayed refs, as
580 * we will consume space for them from the global block reserve.
581 */
582 if (ret && flush == BTRFS_RESERVE_FLUSH_ALL_STEAL) {
583 bytes -= *delayed_refs_bytes;
584 *delayed_refs_bytes = 0;
585 ret = btrfs_reserve_metadata_bytes(fs_info, si, bytes, flush);
586 }
587
588 return ret;
589}
590
591static struct btrfs_trans_handle *
592start_transaction(struct btrfs_root *root, unsigned int num_items,
593 unsigned int type, enum btrfs_reserve_flush_enum flush,
594 bool enforce_qgroups)
595{
596 struct btrfs_fs_info *fs_info = root->fs_info;
597 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
598 struct btrfs_block_rsv *trans_rsv = &fs_info->trans_block_rsv;
599 struct btrfs_trans_handle *h;
600 struct btrfs_transaction *cur_trans;
601 u64 num_bytes = 0;
602 u64 qgroup_reserved = 0;
603 u64 delayed_refs_bytes = 0;
604 bool reloc_reserved = false;
605 bool do_chunk_alloc = false;
606 int ret;
607
608 if (BTRFS_FS_ERROR(fs_info))
609 return ERR_PTR(-EROFS);
610
611 if (current->journal_info) {
612 WARN_ON(type & TRANS_EXTWRITERS);
613 h = current->journal_info;
614 refcount_inc(&h->use_count);
615 WARN_ON(refcount_read(&h->use_count) > 2);
616 h->orig_rsv = h->block_rsv;
617 h->block_rsv = NULL;
618 goto got_it;
619 }
620
621 /*
622 * Do the reservation before we join the transaction so we can do all
623 * the appropriate flushing if need be.
624 */
625 if (num_items && root != fs_info->chunk_root) {
626 qgroup_reserved = num_items * fs_info->nodesize;
627 /*
628 * Use prealloc for now, as there might be a currently running
629 * transaction that could free this reserved space prematurely
630 * by committing.
631 */
632 ret = btrfs_qgroup_reserve_meta_prealloc(root, qgroup_reserved,
633 enforce_qgroups, false);
634 if (ret)
635 return ERR_PTR(ret);
636
637 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
638 /*
639 * If we plan to insert/update/delete "num_items" from a btree,
640 * we will also generate delayed refs for extent buffers in the
641 * respective btree paths, so reserve space for the delayed refs
642 * that will be generated by the caller as it modifies btrees.
643 * Try to reserve them to avoid excessive use of the global
644 * block reserve.
645 */
646 delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info, num_items);
647
648 /*
649 * Do the reservation for the relocation root creation
650 */
651 if (need_reserve_reloc_root(root)) {
652 num_bytes += fs_info->nodesize;
653 reloc_reserved = true;
654 }
655
656 ret = btrfs_reserve_trans_metadata(fs_info, flush, num_bytes,
657 &delayed_refs_bytes);
658 if (ret)
659 goto reserve_fail;
660
661 btrfs_block_rsv_add_bytes(trans_rsv, num_bytes, true);
662
663 if (trans_rsv->space_info->force_alloc)
664 do_chunk_alloc = true;
665 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
666 !btrfs_block_rsv_full(delayed_refs_rsv)) {
667 /*
668 * Some people call with btrfs_start_transaction(root, 0)
669 * because they can be throttled, but have some other mechanism
670 * for reserving space. We still want these guys to refill the
671 * delayed block_rsv so just add 1 items worth of reservation
672 * here.
673 */
674 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
675 if (ret)
676 goto reserve_fail;
677 }
678again:
679 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
680 if (!h) {
681 ret = -ENOMEM;
682 goto alloc_fail;
683 }
684
685 /*
686 * If we are JOIN_NOLOCK we're already committing a transaction and
687 * waiting on this guy, so we don't need to do the sb_start_intwrite
688 * because we're already holding a ref. We need this because we could
689 * have raced in and did an fsync() on a file which can kick a commit
690 * and then we deadlock with somebody doing a freeze.
691 *
692 * If we are ATTACH, it means we just want to catch the current
693 * transaction and commit it, so we needn't do sb_start_intwrite().
694 */
695 if (type & __TRANS_FREEZABLE)
696 sb_start_intwrite(fs_info->sb);
697
698 if (may_wait_transaction(fs_info, type))
699 wait_current_trans(fs_info);
700
701 do {
702 ret = join_transaction(fs_info, type);
703 if (ret == -EBUSY) {
704 wait_current_trans(fs_info);
705 if (unlikely(type == TRANS_ATTACH ||
706 type == TRANS_JOIN_NOSTART))
707 ret = -ENOENT;
708 }
709 } while (ret == -EBUSY);
710
711 if (ret < 0)
712 goto join_fail;
713
714 cur_trans = fs_info->running_transaction;
715
716 h->transid = cur_trans->transid;
717 h->transaction = cur_trans;
718 refcount_set(&h->use_count, 1);
719 h->fs_info = root->fs_info;
720
721 h->type = type;
722 INIT_LIST_HEAD(&h->new_bgs);
723 btrfs_init_metadata_block_rsv(fs_info, &h->delayed_rsv, BTRFS_BLOCK_RSV_DELOPS);
724
725 smp_mb();
726 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
727 may_wait_transaction(fs_info, type)) {
728 current->journal_info = h;
729 btrfs_commit_transaction(h);
730 goto again;
731 }
732
733 if (num_bytes) {
734 trace_btrfs_space_reservation(fs_info, "transaction",
735 h->transid, num_bytes, 1);
736 h->block_rsv = trans_rsv;
737 h->bytes_reserved = num_bytes;
738 if (delayed_refs_bytes > 0) {
739 trace_btrfs_space_reservation(fs_info,
740 "local_delayed_refs_rsv",
741 h->transid,
742 delayed_refs_bytes, 1);
743 h->delayed_refs_bytes_reserved = delayed_refs_bytes;
744 btrfs_block_rsv_add_bytes(&h->delayed_rsv, delayed_refs_bytes, true);
745 delayed_refs_bytes = 0;
746 }
747 h->reloc_reserved = reloc_reserved;
748 }
749
750 /*
751 * Now that we have found a transaction to be a part of, convert the
752 * qgroup reservation from prealloc to pertrans. A different transaction
753 * can't race in and free our pertrans out from under us.
754 */
755 if (qgroup_reserved)
756 btrfs_qgroup_convert_reserved_meta(root, qgroup_reserved);
757
758got_it:
759 if (!current->journal_info)
760 current->journal_info = h;
761
762 /*
763 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
764 * ALLOC_FORCE the first run through, and then we won't allocate for
765 * anybody else who races in later. We don't care about the return
766 * value here.
767 */
768 if (do_chunk_alloc && num_bytes) {
769 u64 flags = h->block_rsv->space_info->flags;
770
771 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
772 CHUNK_ALLOC_NO_FORCE);
773 }
774
775 /*
776 * btrfs_record_root_in_trans() needs to alloc new extents, and may
777 * call btrfs_join_transaction() while we're also starting a
778 * transaction.
779 *
780 * Thus it need to be called after current->journal_info initialized,
781 * or we can deadlock.
782 */
783 ret = btrfs_record_root_in_trans(h, root);
784 if (ret) {
785 /*
786 * The transaction handle is fully initialized and linked with
787 * other structures so it needs to be ended in case of errors,
788 * not just freed.
789 */
790 btrfs_end_transaction(h);
791 return ERR_PTR(ret);
792 }
793
794 return h;
795
796join_fail:
797 if (type & __TRANS_FREEZABLE)
798 sb_end_intwrite(fs_info->sb);
799 kmem_cache_free(btrfs_trans_handle_cachep, h);
800alloc_fail:
801 if (num_bytes)
802 btrfs_block_rsv_release(fs_info, trans_rsv, num_bytes, NULL);
803 if (delayed_refs_bytes)
804 btrfs_space_info_free_bytes_may_use(fs_info, trans_rsv->space_info,
805 delayed_refs_bytes);
806reserve_fail:
807 btrfs_qgroup_free_meta_prealloc(root, qgroup_reserved);
808 return ERR_PTR(ret);
809}
810
811struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
812 unsigned int num_items)
813{
814 return start_transaction(root, num_items, TRANS_START,
815 BTRFS_RESERVE_FLUSH_ALL, true);
816}
817
818struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
819 struct btrfs_root *root,
820 unsigned int num_items)
821{
822 return start_transaction(root, num_items, TRANS_START,
823 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
824}
825
826struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
827{
828 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
829 true);
830}
831
832struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
833{
834 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
835 BTRFS_RESERVE_NO_FLUSH, true);
836}
837
838/*
839 * Similar to regular join but it never starts a transaction when none is
840 * running or when there's a running one at a state >= TRANS_STATE_UNBLOCKED.
841 * This is similar to btrfs_attach_transaction() but it allows the join to
842 * happen if the transaction commit already started but it's not yet in the
843 * "doing" phase (the state is < TRANS_STATE_COMMIT_DOING).
844 */
845struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
846{
847 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
848 BTRFS_RESERVE_NO_FLUSH, true);
849}
850
851/*
852 * Catch the running transaction.
853 *
854 * It is used when we want to commit the current the transaction, but
855 * don't want to start a new one.
856 *
857 * Note: If this function return -ENOENT, it just means there is no
858 * running transaction. But it is possible that the inactive transaction
859 * is still in the memory, not fully on disk. If you hope there is no
860 * inactive transaction in the fs when -ENOENT is returned, you should
861 * invoke
862 * btrfs_attach_transaction_barrier()
863 */
864struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
865{
866 return start_transaction(root, 0, TRANS_ATTACH,
867 BTRFS_RESERVE_NO_FLUSH, true);
868}
869
870/*
871 * Catch the running transaction.
872 *
873 * It is similar to the above function, the difference is this one
874 * will wait for all the inactive transactions until they fully
875 * complete.
876 */
877struct btrfs_trans_handle *
878btrfs_attach_transaction_barrier(struct btrfs_root *root)
879{
880 struct btrfs_trans_handle *trans;
881
882 trans = start_transaction(root, 0, TRANS_ATTACH,
883 BTRFS_RESERVE_NO_FLUSH, true);
884 if (trans == ERR_PTR(-ENOENT)) {
885 int ret;
886
887 ret = btrfs_wait_for_commit(root->fs_info, 0);
888 if (ret)
889 return ERR_PTR(ret);
890 }
891
892 return trans;
893}
894
895/* Wait for a transaction commit to reach at least the given state. */
896static noinline void wait_for_commit(struct btrfs_transaction *commit,
897 const enum btrfs_trans_state min_state)
898{
899 struct btrfs_fs_info *fs_info = commit->fs_info;
900 u64 transid = commit->transid;
901 bool put = false;
902
903 /*
904 * At the moment this function is called with min_state either being
905 * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
906 */
907 if (min_state == TRANS_STATE_COMPLETED)
908 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
909 else
910 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
911
912 while (1) {
913 wait_event(commit->commit_wait, commit->state >= min_state);
914 if (put)
915 btrfs_put_transaction(commit);
916
917 if (min_state < TRANS_STATE_COMPLETED)
918 break;
919
920 /*
921 * A transaction isn't really completed until all of the
922 * previous transactions are completed, but with fsync we can
923 * end up with SUPER_COMMITTED transactions before a COMPLETED
924 * transaction. Wait for those.
925 */
926
927 spin_lock(&fs_info->trans_lock);
928 commit = list_first_entry_or_null(&fs_info->trans_list,
929 struct btrfs_transaction,
930 list);
931 if (!commit || commit->transid > transid) {
932 spin_unlock(&fs_info->trans_lock);
933 break;
934 }
935 refcount_inc(&commit->use_count);
936 put = true;
937 spin_unlock(&fs_info->trans_lock);
938 }
939}
940
941int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
942{
943 struct btrfs_transaction *cur_trans = NULL, *t;
944 int ret = 0;
945
946 if (transid) {
947 if (transid <= btrfs_get_last_trans_committed(fs_info))
948 goto out;
949
950 /* find specified transaction */
951 spin_lock(&fs_info->trans_lock);
952 list_for_each_entry(t, &fs_info->trans_list, list) {
953 if (t->transid == transid) {
954 cur_trans = t;
955 refcount_inc(&cur_trans->use_count);
956 ret = 0;
957 break;
958 }
959 if (t->transid > transid) {
960 ret = 0;
961 break;
962 }
963 }
964 spin_unlock(&fs_info->trans_lock);
965
966 /*
967 * The specified transaction doesn't exist, or we
968 * raced with btrfs_commit_transaction
969 */
970 if (!cur_trans) {
971 if (transid > btrfs_get_last_trans_committed(fs_info))
972 ret = -EINVAL;
973 goto out;
974 }
975 } else {
976 /* find newest transaction that is committing | committed */
977 spin_lock(&fs_info->trans_lock);
978 list_for_each_entry_reverse(t, &fs_info->trans_list,
979 list) {
980 if (t->state >= TRANS_STATE_COMMIT_START) {
981 if (t->state == TRANS_STATE_COMPLETED)
982 break;
983 cur_trans = t;
984 refcount_inc(&cur_trans->use_count);
985 break;
986 }
987 }
988 spin_unlock(&fs_info->trans_lock);
989 if (!cur_trans)
990 goto out; /* nothing committing|committed */
991 }
992
993 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
994 ret = cur_trans->aborted;
995 btrfs_put_transaction(cur_trans);
996out:
997 return ret;
998}
999
1000void btrfs_throttle(struct btrfs_fs_info *fs_info)
1001{
1002 wait_current_trans(fs_info);
1003}
1004
1005bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
1006{
1007 struct btrfs_transaction *cur_trans = trans->transaction;
1008
1009 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
1010 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
1011 return true;
1012
1013 if (btrfs_check_space_for_delayed_refs(trans->fs_info))
1014 return true;
1015
1016 return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
1017}
1018
1019static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
1020
1021{
1022 struct btrfs_fs_info *fs_info = trans->fs_info;
1023
1024 if (!trans->block_rsv) {
1025 ASSERT(!trans->bytes_reserved);
1026 ASSERT(!trans->delayed_refs_bytes_reserved);
1027 return;
1028 }
1029
1030 if (!trans->bytes_reserved) {
1031 ASSERT(!trans->delayed_refs_bytes_reserved);
1032 return;
1033 }
1034
1035 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
1036 trace_btrfs_space_reservation(fs_info, "transaction",
1037 trans->transid, trans->bytes_reserved, 0);
1038 btrfs_block_rsv_release(fs_info, trans->block_rsv,
1039 trans->bytes_reserved, NULL);
1040 trans->bytes_reserved = 0;
1041
1042 if (!trans->delayed_refs_bytes_reserved)
1043 return;
1044
1045 trace_btrfs_space_reservation(fs_info, "local_delayed_refs_rsv",
1046 trans->transid,
1047 trans->delayed_refs_bytes_reserved, 0);
1048 btrfs_block_rsv_release(fs_info, &trans->delayed_rsv,
1049 trans->delayed_refs_bytes_reserved, NULL);
1050 trans->delayed_refs_bytes_reserved = 0;
1051}
1052
1053static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
1054 int throttle)
1055{
1056 struct btrfs_fs_info *info = trans->fs_info;
1057 struct btrfs_transaction *cur_trans = trans->transaction;
1058 int err = 0;
1059
1060 if (refcount_read(&trans->use_count) > 1) {
1061 refcount_dec(&trans->use_count);
1062 trans->block_rsv = trans->orig_rsv;
1063 return 0;
1064 }
1065
1066 btrfs_trans_release_metadata(trans);
1067 trans->block_rsv = NULL;
1068
1069 btrfs_create_pending_block_groups(trans);
1070
1071 btrfs_trans_release_chunk_metadata(trans);
1072
1073 if (trans->type & __TRANS_FREEZABLE)
1074 sb_end_intwrite(info->sb);
1075
1076 WARN_ON(cur_trans != info->running_transaction);
1077 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1078 atomic_dec(&cur_trans->num_writers);
1079 extwriter_counter_dec(cur_trans, trans->type);
1080
1081 cond_wake_up(&cur_trans->writer_wait);
1082
1083 btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1084 btrfs_lockdep_release(info, btrfs_trans_num_writers);
1085
1086 btrfs_put_transaction(cur_trans);
1087
1088 if (current->journal_info == trans)
1089 current->journal_info = NULL;
1090
1091 if (throttle)
1092 btrfs_run_delayed_iputs(info);
1093
1094 if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1095 wake_up_process(info->transaction_kthread);
1096 if (TRANS_ABORTED(trans))
1097 err = trans->aborted;
1098 else
1099 err = -EROFS;
1100 }
1101
1102 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1103 return err;
1104}
1105
1106int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1107{
1108 return __btrfs_end_transaction(trans, 0);
1109}
1110
1111int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1112{
1113 return __btrfs_end_transaction(trans, 1);
1114}
1115
1116/*
1117 * when btree blocks are allocated, they have some corresponding bits set for
1118 * them in one of two extent_io trees. This is used to make sure all of
1119 * those extents are sent to disk but does not wait on them
1120 */
1121int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1122 struct extent_io_tree *dirty_pages, int mark)
1123{
1124 int err = 0;
1125 int werr = 0;
1126 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1127 struct extent_state *cached_state = NULL;
1128 u64 start = 0;
1129 u64 end;
1130
1131 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1132 mark, &cached_state)) {
1133 bool wait_writeback = false;
1134
1135 err = convert_extent_bit(dirty_pages, start, end,
1136 EXTENT_NEED_WAIT,
1137 mark, &cached_state);
1138 /*
1139 * convert_extent_bit can return -ENOMEM, which is most of the
1140 * time a temporary error. So when it happens, ignore the error
1141 * and wait for writeback of this range to finish - because we
1142 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1143 * to __btrfs_wait_marked_extents() would not know that
1144 * writeback for this range started and therefore wouldn't
1145 * wait for it to finish - we don't want to commit a
1146 * superblock that points to btree nodes/leafs for which
1147 * writeback hasn't finished yet (and without errors).
1148 * We cleanup any entries left in the io tree when committing
1149 * the transaction (through extent_io_tree_release()).
1150 */
1151 if (err == -ENOMEM) {
1152 err = 0;
1153 wait_writeback = true;
1154 }
1155 if (!err)
1156 err = filemap_fdatawrite_range(mapping, start, end);
1157 if (err)
1158 werr = err;
1159 else if (wait_writeback)
1160 werr = filemap_fdatawait_range(mapping, start, end);
1161 free_extent_state(cached_state);
1162 cached_state = NULL;
1163 cond_resched();
1164 start = end + 1;
1165 }
1166 return werr;
1167}
1168
1169/*
1170 * when btree blocks are allocated, they have some corresponding bits set for
1171 * them in one of two extent_io trees. This is used to make sure all of
1172 * those extents are on disk for transaction or log commit. We wait
1173 * on all the pages and clear them from the dirty pages state tree
1174 */
1175static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1176 struct extent_io_tree *dirty_pages)
1177{
1178 int err = 0;
1179 int werr = 0;
1180 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1181 struct extent_state *cached_state = NULL;
1182 u64 start = 0;
1183 u64 end;
1184
1185 while (find_first_extent_bit(dirty_pages, start, &start, &end,
1186 EXTENT_NEED_WAIT, &cached_state)) {
1187 /*
1188 * Ignore -ENOMEM errors returned by clear_extent_bit().
1189 * When committing the transaction, we'll remove any entries
1190 * left in the io tree. For a log commit, we don't remove them
1191 * after committing the log because the tree can be accessed
1192 * concurrently - we do it only at transaction commit time when
1193 * it's safe to do it (through extent_io_tree_release()).
1194 */
1195 err = clear_extent_bit(dirty_pages, start, end,
1196 EXTENT_NEED_WAIT, &cached_state);
1197 if (err == -ENOMEM)
1198 err = 0;
1199 if (!err)
1200 err = filemap_fdatawait_range(mapping, start, end);
1201 if (err)
1202 werr = err;
1203 free_extent_state(cached_state);
1204 cached_state = NULL;
1205 cond_resched();
1206 start = end + 1;
1207 }
1208 if (err)
1209 werr = err;
1210 return werr;
1211}
1212
1213static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1214 struct extent_io_tree *dirty_pages)
1215{
1216 bool errors = false;
1217 int err;
1218
1219 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1220 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1221 errors = true;
1222
1223 if (errors && !err)
1224 err = -EIO;
1225 return err;
1226}
1227
1228int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1229{
1230 struct btrfs_fs_info *fs_info = log_root->fs_info;
1231 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1232 bool errors = false;
1233 int err;
1234
1235 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1236
1237 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1238 if ((mark & EXTENT_DIRTY) &&
1239 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1240 errors = true;
1241
1242 if ((mark & EXTENT_NEW) &&
1243 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1244 errors = true;
1245
1246 if (errors && !err)
1247 err = -EIO;
1248 return err;
1249}
1250
1251/*
1252 * When btree blocks are allocated the corresponding extents are marked dirty.
1253 * This function ensures such extents are persisted on disk for transaction or
1254 * log commit.
1255 *
1256 * @trans: transaction whose dirty pages we'd like to write
1257 */
1258static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1259{
1260 int ret;
1261 int ret2;
1262 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1263 struct btrfs_fs_info *fs_info = trans->fs_info;
1264 struct blk_plug plug;
1265
1266 blk_start_plug(&plug);
1267 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1268 blk_finish_plug(&plug);
1269 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1270
1271 extent_io_tree_release(&trans->transaction->dirty_pages);
1272
1273 if (ret)
1274 return ret;
1275 else if (ret2)
1276 return ret2;
1277 else
1278 return 0;
1279}
1280
1281/*
1282 * this is used to update the root pointer in the tree of tree roots.
1283 *
1284 * But, in the case of the extent allocation tree, updating the root
1285 * pointer may allocate blocks which may change the root of the extent
1286 * allocation tree.
1287 *
1288 * So, this loops and repeats and makes sure the cowonly root didn't
1289 * change while the root pointer was being updated in the metadata.
1290 */
1291static int update_cowonly_root(struct btrfs_trans_handle *trans,
1292 struct btrfs_root *root)
1293{
1294 int ret;
1295 u64 old_root_bytenr;
1296 u64 old_root_used;
1297 struct btrfs_fs_info *fs_info = root->fs_info;
1298 struct btrfs_root *tree_root = fs_info->tree_root;
1299
1300 old_root_used = btrfs_root_used(&root->root_item);
1301
1302 while (1) {
1303 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1304 if (old_root_bytenr == root->node->start &&
1305 old_root_used == btrfs_root_used(&root->root_item))
1306 break;
1307
1308 btrfs_set_root_node(&root->root_item, root->node);
1309 ret = btrfs_update_root(trans, tree_root,
1310 &root->root_key,
1311 &root->root_item);
1312 if (ret)
1313 return ret;
1314
1315 old_root_used = btrfs_root_used(&root->root_item);
1316 }
1317
1318 return 0;
1319}
1320
1321/*
1322 * update all the cowonly tree roots on disk
1323 *
1324 * The error handling in this function may not be obvious. Any of the
1325 * failures will cause the file system to go offline. We still need
1326 * to clean up the delayed refs.
1327 */
1328static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1329{
1330 struct btrfs_fs_info *fs_info = trans->fs_info;
1331 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1332 struct list_head *io_bgs = &trans->transaction->io_bgs;
1333 struct list_head *next;
1334 struct extent_buffer *eb;
1335 int ret;
1336
1337 /*
1338 * At this point no one can be using this transaction to modify any tree
1339 * and no one can start another transaction to modify any tree either.
1340 */
1341 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1342
1343 eb = btrfs_lock_root_node(fs_info->tree_root);
1344 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1345 0, &eb, BTRFS_NESTING_COW);
1346 btrfs_tree_unlock(eb);
1347 free_extent_buffer(eb);
1348
1349 if (ret)
1350 return ret;
1351
1352 ret = btrfs_run_dev_stats(trans);
1353 if (ret)
1354 return ret;
1355 ret = btrfs_run_dev_replace(trans);
1356 if (ret)
1357 return ret;
1358 ret = btrfs_run_qgroups(trans);
1359 if (ret)
1360 return ret;
1361
1362 ret = btrfs_setup_space_cache(trans);
1363 if (ret)
1364 return ret;
1365
1366again:
1367 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1368 struct btrfs_root *root;
1369 next = fs_info->dirty_cowonly_roots.next;
1370 list_del_init(next);
1371 root = list_entry(next, struct btrfs_root, dirty_list);
1372 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1373
1374 list_add_tail(&root->dirty_list,
1375 &trans->transaction->switch_commits);
1376 ret = update_cowonly_root(trans, root);
1377 if (ret)
1378 return ret;
1379 }
1380
1381 /* Now flush any delayed refs generated by updating all of the roots */
1382 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1383 if (ret)
1384 return ret;
1385
1386 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1387 ret = btrfs_write_dirty_block_groups(trans);
1388 if (ret)
1389 return ret;
1390
1391 /*
1392 * We're writing the dirty block groups, which could generate
1393 * delayed refs, which could generate more dirty block groups,
1394 * so we want to keep this flushing in this loop to make sure
1395 * everything gets run.
1396 */
1397 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1398 if (ret)
1399 return ret;
1400 }
1401
1402 if (!list_empty(&fs_info->dirty_cowonly_roots))
1403 goto again;
1404
1405 /* Update dev-replace pointer once everything is committed */
1406 fs_info->dev_replace.committed_cursor_left =
1407 fs_info->dev_replace.cursor_left_last_write_of_item;
1408
1409 return 0;
1410}
1411
1412/*
1413 * If we had a pending drop we need to see if there are any others left in our
1414 * dead roots list, and if not clear our bit and wake any waiters.
1415 */
1416void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1417{
1418 /*
1419 * We put the drop in progress roots at the front of the list, so if the
1420 * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1421 * up.
1422 */
1423 spin_lock(&fs_info->trans_lock);
1424 if (!list_empty(&fs_info->dead_roots)) {
1425 struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1426 struct btrfs_root,
1427 root_list);
1428 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1429 spin_unlock(&fs_info->trans_lock);
1430 return;
1431 }
1432 }
1433 spin_unlock(&fs_info->trans_lock);
1434
1435 btrfs_wake_unfinished_drop(fs_info);
1436}
1437
1438/*
1439 * dead roots are old snapshots that need to be deleted. This allocates
1440 * a dirty root struct and adds it into the list of dead roots that need to
1441 * be deleted
1442 */
1443void btrfs_add_dead_root(struct btrfs_root *root)
1444{
1445 struct btrfs_fs_info *fs_info = root->fs_info;
1446
1447 spin_lock(&fs_info->trans_lock);
1448 if (list_empty(&root->root_list)) {
1449 btrfs_grab_root(root);
1450
1451 /* We want to process the partially complete drops first. */
1452 if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1453 list_add(&root->root_list, &fs_info->dead_roots);
1454 else
1455 list_add_tail(&root->root_list, &fs_info->dead_roots);
1456 }
1457 spin_unlock(&fs_info->trans_lock);
1458}
1459
1460/*
1461 * Update each subvolume root and its relocation root, if it exists, in the tree
1462 * of tree roots. Also free log roots if they exist.
1463 */
1464static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1465{
1466 struct btrfs_fs_info *fs_info = trans->fs_info;
1467 struct btrfs_root *gang[8];
1468 int i;
1469 int ret;
1470
1471 /*
1472 * At this point no one can be using this transaction to modify any tree
1473 * and no one can start another transaction to modify any tree either.
1474 */
1475 ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1476
1477 spin_lock(&fs_info->fs_roots_radix_lock);
1478 while (1) {
1479 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1480 (void **)gang, 0,
1481 ARRAY_SIZE(gang),
1482 BTRFS_ROOT_TRANS_TAG);
1483 if (ret == 0)
1484 break;
1485 for (i = 0; i < ret; i++) {
1486 struct btrfs_root *root = gang[i];
1487 int ret2;
1488
1489 /*
1490 * At this point we can neither have tasks logging inodes
1491 * from a root nor trying to commit a log tree.
1492 */
1493 ASSERT(atomic_read(&root->log_writers) == 0);
1494 ASSERT(atomic_read(&root->log_commit[0]) == 0);
1495 ASSERT(atomic_read(&root->log_commit[1]) == 0);
1496
1497 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1498 (unsigned long)root->root_key.objectid,
1499 BTRFS_ROOT_TRANS_TAG);
1500 spin_unlock(&fs_info->fs_roots_radix_lock);
1501
1502 btrfs_free_log(trans, root);
1503 ret2 = btrfs_update_reloc_root(trans, root);
1504 if (ret2)
1505 return ret2;
1506
1507 /* see comments in should_cow_block() */
1508 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1509 smp_mb__after_atomic();
1510
1511 if (root->commit_root != root->node) {
1512 list_add_tail(&root->dirty_list,
1513 &trans->transaction->switch_commits);
1514 btrfs_set_root_node(&root->root_item,
1515 root->node);
1516 }
1517
1518 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1519 &root->root_key,
1520 &root->root_item);
1521 if (ret2)
1522 return ret2;
1523 spin_lock(&fs_info->fs_roots_radix_lock);
1524 btrfs_qgroup_free_meta_all_pertrans(root);
1525 }
1526 }
1527 spin_unlock(&fs_info->fs_roots_radix_lock);
1528 return 0;
1529}
1530
1531/*
1532 * Do all special snapshot related qgroup dirty hack.
1533 *
1534 * Will do all needed qgroup inherit and dirty hack like switch commit
1535 * roots inside one transaction and write all btree into disk, to make
1536 * qgroup works.
1537 */
1538static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1539 struct btrfs_root *src,
1540 struct btrfs_root *parent,
1541 struct btrfs_qgroup_inherit *inherit,
1542 u64 dst_objectid)
1543{
1544 struct btrfs_fs_info *fs_info = src->fs_info;
1545 int ret;
1546
1547 /*
1548 * Save some performance in the case that qgroups are not enabled. If
1549 * this check races with the ioctl, rescan will kick in anyway.
1550 */
1551 if (!btrfs_qgroup_full_accounting(fs_info))
1552 return 0;
1553
1554 /*
1555 * Ensure dirty @src will be committed. Or, after coming
1556 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1557 * recorded root will never be updated again, causing an outdated root
1558 * item.
1559 */
1560 ret = record_root_in_trans(trans, src, 1);
1561 if (ret)
1562 return ret;
1563
1564 /*
1565 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1566 * src root, so we must run the delayed refs here.
1567 *
1568 * However this isn't particularly fool proof, because there's no
1569 * synchronization keeping us from changing the tree after this point
1570 * before we do the qgroup_inherit, or even from making changes while
1571 * we're doing the qgroup_inherit. But that's a problem for the future,
1572 * for now flush the delayed refs to narrow the race window where the
1573 * qgroup counters could end up wrong.
1574 */
1575 ret = btrfs_run_delayed_refs(trans, U64_MAX);
1576 if (ret) {
1577 btrfs_abort_transaction(trans, ret);
1578 return ret;
1579 }
1580
1581 ret = commit_fs_roots(trans);
1582 if (ret)
1583 goto out;
1584 ret = btrfs_qgroup_account_extents(trans);
1585 if (ret < 0)
1586 goto out;
1587
1588 /* Now qgroup are all updated, we can inherit it to new qgroups */
1589 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1590 parent->root_key.objectid, inherit);
1591 if (ret < 0)
1592 goto out;
1593
1594 /*
1595 * Now we do a simplified commit transaction, which will:
1596 * 1) commit all subvolume and extent tree
1597 * To ensure all subvolume and extent tree have a valid
1598 * commit_root to accounting later insert_dir_item()
1599 * 2) write all btree blocks onto disk
1600 * This is to make sure later btree modification will be cowed
1601 * Or commit_root can be populated and cause wrong qgroup numbers
1602 * In this simplified commit, we don't really care about other trees
1603 * like chunk and root tree, as they won't affect qgroup.
1604 * And we don't write super to avoid half committed status.
1605 */
1606 ret = commit_cowonly_roots(trans);
1607 if (ret)
1608 goto out;
1609 switch_commit_roots(trans);
1610 ret = btrfs_write_and_wait_transaction(trans);
1611 if (ret)
1612 btrfs_handle_fs_error(fs_info, ret,
1613 "Error while writing out transaction for qgroup");
1614
1615out:
1616 /*
1617 * Force parent root to be updated, as we recorded it before so its
1618 * last_trans == cur_transid.
1619 * Or it won't be committed again onto disk after later
1620 * insert_dir_item()
1621 */
1622 if (!ret)
1623 ret = record_root_in_trans(trans, parent, 1);
1624 return ret;
1625}
1626
1627/*
1628 * new snapshots need to be created at a very specific time in the
1629 * transaction commit. This does the actual creation.
1630 *
1631 * Note:
1632 * If the error which may affect the commitment of the current transaction
1633 * happens, we should return the error number. If the error which just affect
1634 * the creation of the pending snapshots, just return 0.
1635 */
1636static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1637 struct btrfs_pending_snapshot *pending)
1638{
1639
1640 struct btrfs_fs_info *fs_info = trans->fs_info;
1641 struct btrfs_key key;
1642 struct btrfs_root_item *new_root_item;
1643 struct btrfs_root *tree_root = fs_info->tree_root;
1644 struct btrfs_root *root = pending->root;
1645 struct btrfs_root *parent_root;
1646 struct btrfs_block_rsv *rsv;
1647 struct inode *parent_inode = pending->dir;
1648 struct btrfs_path *path;
1649 struct btrfs_dir_item *dir_item;
1650 struct extent_buffer *tmp;
1651 struct extent_buffer *old;
1652 struct timespec64 cur_time;
1653 int ret = 0;
1654 u64 to_reserve = 0;
1655 u64 index = 0;
1656 u64 objectid;
1657 u64 root_flags;
1658 unsigned int nofs_flags;
1659 struct fscrypt_name fname;
1660
1661 ASSERT(pending->path);
1662 path = pending->path;
1663
1664 ASSERT(pending->root_item);
1665 new_root_item = pending->root_item;
1666
1667 /*
1668 * We're inside a transaction and must make sure that any potential
1669 * allocations with GFP_KERNEL in fscrypt won't recurse back to
1670 * filesystem.
1671 */
1672 nofs_flags = memalloc_nofs_save();
1673 pending->error = fscrypt_setup_filename(parent_inode,
1674 &pending->dentry->d_name, 0,
1675 &fname);
1676 memalloc_nofs_restore(nofs_flags);
1677 if (pending->error)
1678 goto free_pending;
1679
1680 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1681 if (pending->error)
1682 goto free_fname;
1683
1684 /*
1685 * Make qgroup to skip current new snapshot's qgroupid, as it is
1686 * accounted by later btrfs_qgroup_inherit().
1687 */
1688 btrfs_set_skip_qgroup(trans, objectid);
1689
1690 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1691
1692 if (to_reserve > 0) {
1693 pending->error = btrfs_block_rsv_add(fs_info,
1694 &pending->block_rsv,
1695 to_reserve,
1696 BTRFS_RESERVE_NO_FLUSH);
1697 if (pending->error)
1698 goto clear_skip_qgroup;
1699 }
1700
1701 key.objectid = objectid;
1702 key.offset = (u64)-1;
1703 key.type = BTRFS_ROOT_ITEM_KEY;
1704
1705 rsv = trans->block_rsv;
1706 trans->block_rsv = &pending->block_rsv;
1707 trans->bytes_reserved = trans->block_rsv->reserved;
1708 trace_btrfs_space_reservation(fs_info, "transaction",
1709 trans->transid,
1710 trans->bytes_reserved, 1);
1711 parent_root = BTRFS_I(parent_inode)->root;
1712 ret = record_root_in_trans(trans, parent_root, 0);
1713 if (ret)
1714 goto fail;
1715 cur_time = current_time(parent_inode);
1716
1717 /*
1718 * insert the directory item
1719 */
1720 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1721 if (ret) {
1722 btrfs_abort_transaction(trans, ret);
1723 goto fail;
1724 }
1725
1726 /* check if there is a file/dir which has the same name. */
1727 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1728 btrfs_ino(BTRFS_I(parent_inode)),
1729 &fname.disk_name, 0);
1730 if (dir_item != NULL && !IS_ERR(dir_item)) {
1731 pending->error = -EEXIST;
1732 goto dir_item_existed;
1733 } else if (IS_ERR(dir_item)) {
1734 ret = PTR_ERR(dir_item);
1735 btrfs_abort_transaction(trans, ret);
1736 goto fail;
1737 }
1738 btrfs_release_path(path);
1739
1740 ret = btrfs_create_qgroup(trans, objectid);
1741 if (ret && ret != -EEXIST) {
1742 btrfs_abort_transaction(trans, ret);
1743 goto fail;
1744 }
1745
1746 /*
1747 * pull in the delayed directory update
1748 * and the delayed inode item
1749 * otherwise we corrupt the FS during
1750 * snapshot
1751 */
1752 ret = btrfs_run_delayed_items(trans);
1753 if (ret) { /* Transaction aborted */
1754 btrfs_abort_transaction(trans, ret);
1755 goto fail;
1756 }
1757
1758 ret = record_root_in_trans(trans, root, 0);
1759 if (ret) {
1760 btrfs_abort_transaction(trans, ret);
1761 goto fail;
1762 }
1763 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1764 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1765 btrfs_check_and_init_root_item(new_root_item);
1766
1767 root_flags = btrfs_root_flags(new_root_item);
1768 if (pending->readonly)
1769 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1770 else
1771 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1772 btrfs_set_root_flags(new_root_item, root_flags);
1773
1774 btrfs_set_root_generation_v2(new_root_item,
1775 trans->transid);
1776 generate_random_guid(new_root_item->uuid);
1777 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1778 BTRFS_UUID_SIZE);
1779 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1780 memset(new_root_item->received_uuid, 0,
1781 sizeof(new_root_item->received_uuid));
1782 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1783 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1784 btrfs_set_root_stransid(new_root_item, 0);
1785 btrfs_set_root_rtransid(new_root_item, 0);
1786 }
1787 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1788 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1789 btrfs_set_root_otransid(new_root_item, trans->transid);
1790
1791 old = btrfs_lock_root_node(root);
1792 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1793 BTRFS_NESTING_COW);
1794 if (ret) {
1795 btrfs_tree_unlock(old);
1796 free_extent_buffer(old);
1797 btrfs_abort_transaction(trans, ret);
1798 goto fail;
1799 }
1800
1801 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1802 /* clean up in any case */
1803 btrfs_tree_unlock(old);
1804 free_extent_buffer(old);
1805 if (ret) {
1806 btrfs_abort_transaction(trans, ret);
1807 goto fail;
1808 }
1809 /* see comments in should_cow_block() */
1810 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1811 smp_wmb();
1812
1813 btrfs_set_root_node(new_root_item, tmp);
1814 /* record when the snapshot was created in key.offset */
1815 key.offset = trans->transid;
1816 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1817 btrfs_tree_unlock(tmp);
1818 free_extent_buffer(tmp);
1819 if (ret) {
1820 btrfs_abort_transaction(trans, ret);
1821 goto fail;
1822 }
1823
1824 /*
1825 * insert root back/forward references
1826 */
1827 ret = btrfs_add_root_ref(trans, objectid,
1828 parent_root->root_key.objectid,
1829 btrfs_ino(BTRFS_I(parent_inode)), index,
1830 &fname.disk_name);
1831 if (ret) {
1832 btrfs_abort_transaction(trans, ret);
1833 goto fail;
1834 }
1835
1836 key.offset = (u64)-1;
1837 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev);
1838 if (IS_ERR(pending->snap)) {
1839 ret = PTR_ERR(pending->snap);
1840 pending->snap = NULL;
1841 btrfs_abort_transaction(trans, ret);
1842 goto fail;
1843 }
1844
1845 ret = btrfs_reloc_post_snapshot(trans, pending);
1846 if (ret) {
1847 btrfs_abort_transaction(trans, ret);
1848 goto fail;
1849 }
1850
1851 /*
1852 * Do special qgroup accounting for snapshot, as we do some qgroup
1853 * snapshot hack to do fast snapshot.
1854 * To co-operate with that hack, we do hack again.
1855 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1856 */
1857 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_FULL)
1858 ret = qgroup_account_snapshot(trans, root, parent_root,
1859 pending->inherit, objectid);
1860 else if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE)
1861 ret = btrfs_qgroup_inherit(trans, root->root_key.objectid, objectid,
1862 parent_root->root_key.objectid, pending->inherit);
1863 if (ret < 0)
1864 goto fail;
1865
1866 ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1867 BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1868 index);
1869 /* We have check then name at the beginning, so it is impossible. */
1870 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1871 if (ret) {
1872 btrfs_abort_transaction(trans, ret);
1873 goto fail;
1874 }
1875
1876 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1877 fname.disk_name.len * 2);
1878 inode_set_mtime_to_ts(parent_inode,
1879 inode_set_ctime_current(parent_inode));
1880 ret = btrfs_update_inode_fallback(trans, BTRFS_I(parent_inode));
1881 if (ret) {
1882 btrfs_abort_transaction(trans, ret);
1883 goto fail;
1884 }
1885 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1886 BTRFS_UUID_KEY_SUBVOL,
1887 objectid);
1888 if (ret) {
1889 btrfs_abort_transaction(trans, ret);
1890 goto fail;
1891 }
1892 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1893 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1894 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1895 objectid);
1896 if (ret && ret != -EEXIST) {
1897 btrfs_abort_transaction(trans, ret);
1898 goto fail;
1899 }
1900 }
1901
1902fail:
1903 pending->error = ret;
1904dir_item_existed:
1905 trans->block_rsv = rsv;
1906 trans->bytes_reserved = 0;
1907clear_skip_qgroup:
1908 btrfs_clear_skip_qgroup(trans);
1909free_fname:
1910 fscrypt_free_filename(&fname);
1911free_pending:
1912 kfree(new_root_item);
1913 pending->root_item = NULL;
1914 btrfs_free_path(path);
1915 pending->path = NULL;
1916
1917 return ret;
1918}
1919
1920/*
1921 * create all the snapshots we've scheduled for creation
1922 */
1923static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1924{
1925 struct btrfs_pending_snapshot *pending, *next;
1926 struct list_head *head = &trans->transaction->pending_snapshots;
1927 int ret = 0;
1928
1929 list_for_each_entry_safe(pending, next, head, list) {
1930 list_del(&pending->list);
1931 ret = create_pending_snapshot(trans, pending);
1932 if (ret)
1933 break;
1934 }
1935 return ret;
1936}
1937
1938static void update_super_roots(struct btrfs_fs_info *fs_info)
1939{
1940 struct btrfs_root_item *root_item;
1941 struct btrfs_super_block *super;
1942
1943 super = fs_info->super_copy;
1944
1945 root_item = &fs_info->chunk_root->root_item;
1946 super->chunk_root = root_item->bytenr;
1947 super->chunk_root_generation = root_item->generation;
1948 super->chunk_root_level = root_item->level;
1949
1950 root_item = &fs_info->tree_root->root_item;
1951 super->root = root_item->bytenr;
1952 super->generation = root_item->generation;
1953 super->root_level = root_item->level;
1954 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1955 super->cache_generation = root_item->generation;
1956 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1957 super->cache_generation = 0;
1958 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1959 super->uuid_tree_generation = root_item->generation;
1960}
1961
1962int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1963{
1964 struct btrfs_transaction *trans;
1965 int ret = 0;
1966
1967 spin_lock(&info->trans_lock);
1968 trans = info->running_transaction;
1969 if (trans)
1970 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1971 spin_unlock(&info->trans_lock);
1972 return ret;
1973}
1974
1975int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1976{
1977 struct btrfs_transaction *trans;
1978 int ret = 0;
1979
1980 spin_lock(&info->trans_lock);
1981 trans = info->running_transaction;
1982 if (trans)
1983 ret = is_transaction_blocked(trans);
1984 spin_unlock(&info->trans_lock);
1985 return ret;
1986}
1987
1988void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1989{
1990 struct btrfs_fs_info *fs_info = trans->fs_info;
1991 struct btrfs_transaction *cur_trans;
1992
1993 /* Kick the transaction kthread. */
1994 set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1995 wake_up_process(fs_info->transaction_kthread);
1996
1997 /* take transaction reference */
1998 cur_trans = trans->transaction;
1999 refcount_inc(&cur_trans->use_count);
2000
2001 btrfs_end_transaction(trans);
2002
2003 /*
2004 * Wait for the current transaction commit to start and block
2005 * subsequent transaction joins
2006 */
2007 btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2008 wait_event(fs_info->transaction_blocked_wait,
2009 cur_trans->state >= TRANS_STATE_COMMIT_START ||
2010 TRANS_ABORTED(cur_trans));
2011 btrfs_put_transaction(cur_trans);
2012}
2013
2014static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
2015{
2016 struct btrfs_fs_info *fs_info = trans->fs_info;
2017 struct btrfs_transaction *cur_trans = trans->transaction;
2018
2019 WARN_ON(refcount_read(&trans->use_count) > 1);
2020
2021 btrfs_abort_transaction(trans, err);
2022
2023 spin_lock(&fs_info->trans_lock);
2024
2025 /*
2026 * If the transaction is removed from the list, it means this
2027 * transaction has been committed successfully, so it is impossible
2028 * to call the cleanup function.
2029 */
2030 BUG_ON(list_empty(&cur_trans->list));
2031
2032 if (cur_trans == fs_info->running_transaction) {
2033 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2034 spin_unlock(&fs_info->trans_lock);
2035
2036 /*
2037 * The thread has already released the lockdep map as reader
2038 * already in btrfs_commit_transaction().
2039 */
2040 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2041 wait_event(cur_trans->writer_wait,
2042 atomic_read(&cur_trans->num_writers) == 1);
2043
2044 spin_lock(&fs_info->trans_lock);
2045 }
2046
2047 /*
2048 * Now that we know no one else is still using the transaction we can
2049 * remove the transaction from the list of transactions. This avoids
2050 * the transaction kthread from cleaning up the transaction while some
2051 * other task is still using it, which could result in a use-after-free
2052 * on things like log trees, as it forces the transaction kthread to
2053 * wait for this transaction to be cleaned up by us.
2054 */
2055 list_del_init(&cur_trans->list);
2056
2057 spin_unlock(&fs_info->trans_lock);
2058
2059 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
2060
2061 spin_lock(&fs_info->trans_lock);
2062 if (cur_trans == fs_info->running_transaction)
2063 fs_info->running_transaction = NULL;
2064 spin_unlock(&fs_info->trans_lock);
2065
2066 if (trans->type & __TRANS_FREEZABLE)
2067 sb_end_intwrite(fs_info->sb);
2068 btrfs_put_transaction(cur_trans);
2069 btrfs_put_transaction(cur_trans);
2070
2071 trace_btrfs_transaction_commit(fs_info);
2072
2073 if (current->journal_info == trans)
2074 current->journal_info = NULL;
2075
2076 /*
2077 * If relocation is running, we can't cancel scrub because that will
2078 * result in a deadlock. Before relocating a block group, relocation
2079 * pauses scrub, then starts and commits a transaction before unpausing
2080 * scrub. If the transaction commit is being done by the relocation
2081 * task or triggered by another task and the relocation task is waiting
2082 * for the commit, and we end up here due to an error in the commit
2083 * path, then calling btrfs_scrub_cancel() will deadlock, as we are
2084 * asking for scrub to stop while having it asked to be paused higher
2085 * above in relocation code.
2086 */
2087 if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
2088 btrfs_scrub_cancel(fs_info);
2089
2090 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2091}
2092
2093/*
2094 * Release reserved delayed ref space of all pending block groups of the
2095 * transaction and remove them from the list
2096 */
2097static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2098{
2099 struct btrfs_fs_info *fs_info = trans->fs_info;
2100 struct btrfs_block_group *block_group, *tmp;
2101
2102 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2103 btrfs_dec_delayed_refs_rsv_bg_inserts(fs_info);
2104 list_del_init(&block_group->bg_list);
2105 }
2106}
2107
2108static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2109{
2110 /*
2111 * We use try_to_writeback_inodes_sb() here because if we used
2112 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2113 * Currently are holding the fs freeze lock, if we do an async flush
2114 * we'll do btrfs_join_transaction() and deadlock because we need to
2115 * wait for the fs freeze lock. Using the direct flushing we benefit
2116 * from already being in a transaction and our join_transaction doesn't
2117 * have to re-take the fs freeze lock.
2118 *
2119 * Note that try_to_writeback_inodes_sb() will only trigger writeback
2120 * if it can read lock sb->s_umount. It will always be able to lock it,
2121 * except when the filesystem is being unmounted or being frozen, but in
2122 * those cases sync_filesystem() is called, which results in calling
2123 * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2124 * Note that we don't call writeback_inodes_sb() directly, because it
2125 * will emit a warning if sb->s_umount is not locked.
2126 */
2127 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2128 try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2129 return 0;
2130}
2131
2132static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2133{
2134 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2135 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2136}
2137
2138/*
2139 * Add a pending snapshot associated with the given transaction handle to the
2140 * respective handle. This must be called after the transaction commit started
2141 * and while holding fs_info->trans_lock.
2142 * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2143 * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2144 * returns an error.
2145 */
2146static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2147{
2148 struct btrfs_transaction *cur_trans = trans->transaction;
2149
2150 if (!trans->pending_snapshot)
2151 return;
2152
2153 lockdep_assert_held(&trans->fs_info->trans_lock);
2154 ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_PREP);
2155
2156 list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2157}
2158
2159static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
2160{
2161 fs_info->commit_stats.commit_count++;
2162 fs_info->commit_stats.last_commit_dur = interval;
2163 fs_info->commit_stats.max_commit_dur =
2164 max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2165 fs_info->commit_stats.total_commit_dur += interval;
2166}
2167
2168int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2169{
2170 struct btrfs_fs_info *fs_info = trans->fs_info;
2171 struct btrfs_transaction *cur_trans = trans->transaction;
2172 struct btrfs_transaction *prev_trans = NULL;
2173 int ret;
2174 ktime_t start_time;
2175 ktime_t interval;
2176
2177 ASSERT(refcount_read(&trans->use_count) == 1);
2178 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2179
2180 clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2181
2182 /* Stop the commit early if ->aborted is set */
2183 if (TRANS_ABORTED(cur_trans)) {
2184 ret = cur_trans->aborted;
2185 goto lockdep_trans_commit_start_release;
2186 }
2187
2188 btrfs_trans_release_metadata(trans);
2189 trans->block_rsv = NULL;
2190
2191 /*
2192 * We only want one transaction commit doing the flushing so we do not
2193 * waste a bunch of time on lock contention on the extent root node.
2194 */
2195 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2196 &cur_trans->delayed_refs.flags)) {
2197 /*
2198 * Make a pass through all the delayed refs we have so far.
2199 * Any running threads may add more while we are here.
2200 */
2201 ret = btrfs_run_delayed_refs(trans, 0);
2202 if (ret)
2203 goto lockdep_trans_commit_start_release;
2204 }
2205
2206 btrfs_create_pending_block_groups(trans);
2207
2208 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2209 int run_it = 0;
2210
2211 /* this mutex is also taken before trying to set
2212 * block groups readonly. We need to make sure
2213 * that nobody has set a block group readonly
2214 * after a extents from that block group have been
2215 * allocated for cache files. btrfs_set_block_group_ro
2216 * will wait for the transaction to commit if it
2217 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2218 *
2219 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2220 * only one process starts all the block group IO. It wouldn't
2221 * hurt to have more than one go through, but there's no
2222 * real advantage to it either.
2223 */
2224 mutex_lock(&fs_info->ro_block_group_mutex);
2225 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2226 &cur_trans->flags))
2227 run_it = 1;
2228 mutex_unlock(&fs_info->ro_block_group_mutex);
2229
2230 if (run_it) {
2231 ret = btrfs_start_dirty_block_groups(trans);
2232 if (ret)
2233 goto lockdep_trans_commit_start_release;
2234 }
2235 }
2236
2237 spin_lock(&fs_info->trans_lock);
2238 if (cur_trans->state >= TRANS_STATE_COMMIT_PREP) {
2239 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2240
2241 add_pending_snapshot(trans);
2242
2243 spin_unlock(&fs_info->trans_lock);
2244 refcount_inc(&cur_trans->use_count);
2245
2246 if (trans->in_fsync)
2247 want_state = TRANS_STATE_SUPER_COMMITTED;
2248
2249 btrfs_trans_state_lockdep_release(fs_info,
2250 BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2251 ret = btrfs_end_transaction(trans);
2252 wait_for_commit(cur_trans, want_state);
2253
2254 if (TRANS_ABORTED(cur_trans))
2255 ret = cur_trans->aborted;
2256
2257 btrfs_put_transaction(cur_trans);
2258
2259 return ret;
2260 }
2261
2262 cur_trans->state = TRANS_STATE_COMMIT_PREP;
2263 wake_up(&fs_info->transaction_blocked_wait);
2264 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2265
2266 if (cur_trans->list.prev != &fs_info->trans_list) {
2267 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2268
2269 if (trans->in_fsync)
2270 want_state = TRANS_STATE_SUPER_COMMITTED;
2271
2272 prev_trans = list_entry(cur_trans->list.prev,
2273 struct btrfs_transaction, list);
2274 if (prev_trans->state < want_state) {
2275 refcount_inc(&prev_trans->use_count);
2276 spin_unlock(&fs_info->trans_lock);
2277
2278 wait_for_commit(prev_trans, want_state);
2279
2280 ret = READ_ONCE(prev_trans->aborted);
2281
2282 btrfs_put_transaction(prev_trans);
2283 if (ret)
2284 goto lockdep_release;
2285 spin_lock(&fs_info->trans_lock);
2286 }
2287 } else {
2288 /*
2289 * The previous transaction was aborted and was already removed
2290 * from the list of transactions at fs_info->trans_list. So we
2291 * abort to prevent writing a new superblock that reflects a
2292 * corrupt state (pointing to trees with unwritten nodes/leafs).
2293 */
2294 if (BTRFS_FS_ERROR(fs_info)) {
2295 spin_unlock(&fs_info->trans_lock);
2296 ret = -EROFS;
2297 goto lockdep_release;
2298 }
2299 }
2300
2301 cur_trans->state = TRANS_STATE_COMMIT_START;
2302 wake_up(&fs_info->transaction_blocked_wait);
2303 spin_unlock(&fs_info->trans_lock);
2304
2305 /*
2306 * Get the time spent on the work done by the commit thread and not
2307 * the time spent waiting on a previous commit
2308 */
2309 start_time = ktime_get_ns();
2310
2311 extwriter_counter_dec(cur_trans, trans->type);
2312
2313 ret = btrfs_start_delalloc_flush(fs_info);
2314 if (ret)
2315 goto lockdep_release;
2316
2317 ret = btrfs_run_delayed_items(trans);
2318 if (ret)
2319 goto lockdep_release;
2320
2321 /*
2322 * The thread has started/joined the transaction thus it holds the
2323 * lockdep map as a reader. It has to release it before acquiring the
2324 * lockdep map as a writer.
2325 */
2326 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2327 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2328 wait_event(cur_trans->writer_wait,
2329 extwriter_counter_read(cur_trans) == 0);
2330
2331 /* some pending stuffs might be added after the previous flush. */
2332 ret = btrfs_run_delayed_items(trans);
2333 if (ret) {
2334 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2335 goto cleanup_transaction;
2336 }
2337
2338 btrfs_wait_delalloc_flush(fs_info);
2339
2340 /*
2341 * Wait for all ordered extents started by a fast fsync that joined this
2342 * transaction. Otherwise if this transaction commits before the ordered
2343 * extents complete we lose logged data after a power failure.
2344 */
2345 btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2346 wait_event(cur_trans->pending_wait,
2347 atomic_read(&cur_trans->pending_ordered) == 0);
2348
2349 btrfs_scrub_pause(fs_info);
2350 /*
2351 * Ok now we need to make sure to block out any other joins while we
2352 * commit the transaction. We could have started a join before setting
2353 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2354 */
2355 spin_lock(&fs_info->trans_lock);
2356 add_pending_snapshot(trans);
2357 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2358 spin_unlock(&fs_info->trans_lock);
2359
2360 /*
2361 * The thread has started/joined the transaction thus it holds the
2362 * lockdep map as a reader. It has to release it before acquiring the
2363 * lockdep map as a writer.
2364 */
2365 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2366 btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2367 wait_event(cur_trans->writer_wait,
2368 atomic_read(&cur_trans->num_writers) == 1);
2369
2370 /*
2371 * Make lockdep happy by acquiring the state locks after
2372 * btrfs_trans_num_writers is released. If we acquired the state locks
2373 * before releasing the btrfs_trans_num_writers lock then lockdep would
2374 * complain because we did not follow the reverse order unlocking rule.
2375 */
2376 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2377 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2378 btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2379
2380 /*
2381 * We've started the commit, clear the flag in case we were triggered to
2382 * do an async commit but somebody else started before the transaction
2383 * kthread could do the work.
2384 */
2385 clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2386
2387 if (TRANS_ABORTED(cur_trans)) {
2388 ret = cur_trans->aborted;
2389 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2390 goto scrub_continue;
2391 }
2392 /*
2393 * the reloc mutex makes sure that we stop
2394 * the balancing code from coming in and moving
2395 * extents around in the middle of the commit
2396 */
2397 mutex_lock(&fs_info->reloc_mutex);
2398
2399 /*
2400 * We needn't worry about the delayed items because we will
2401 * deal with them in create_pending_snapshot(), which is the
2402 * core function of the snapshot creation.
2403 */
2404 ret = create_pending_snapshots(trans);
2405 if (ret)
2406 goto unlock_reloc;
2407
2408 /*
2409 * We insert the dir indexes of the snapshots and update the inode
2410 * of the snapshots' parents after the snapshot creation, so there
2411 * are some delayed items which are not dealt with. Now deal with
2412 * them.
2413 *
2414 * We needn't worry that this operation will corrupt the snapshots,
2415 * because all the tree which are snapshoted will be forced to COW
2416 * the nodes and leaves.
2417 */
2418 ret = btrfs_run_delayed_items(trans);
2419 if (ret)
2420 goto unlock_reloc;
2421
2422 ret = btrfs_run_delayed_refs(trans, U64_MAX);
2423 if (ret)
2424 goto unlock_reloc;
2425
2426 /*
2427 * make sure none of the code above managed to slip in a
2428 * delayed item
2429 */
2430 btrfs_assert_delayed_root_empty(fs_info);
2431
2432 WARN_ON(cur_trans != trans->transaction);
2433
2434 ret = commit_fs_roots(trans);
2435 if (ret)
2436 goto unlock_reloc;
2437
2438 /* commit_fs_roots gets rid of all the tree log roots, it is now
2439 * safe to free the root of tree log roots
2440 */
2441 btrfs_free_log_root_tree(trans, fs_info);
2442
2443 /*
2444 * Since fs roots are all committed, we can get a quite accurate
2445 * new_roots. So let's do quota accounting.
2446 */
2447 ret = btrfs_qgroup_account_extents(trans);
2448 if (ret < 0)
2449 goto unlock_reloc;
2450
2451 ret = commit_cowonly_roots(trans);
2452 if (ret)
2453 goto unlock_reloc;
2454
2455 /*
2456 * The tasks which save the space cache and inode cache may also
2457 * update ->aborted, check it.
2458 */
2459 if (TRANS_ABORTED(cur_trans)) {
2460 ret = cur_trans->aborted;
2461 goto unlock_reloc;
2462 }
2463
2464 cur_trans = fs_info->running_transaction;
2465
2466 btrfs_set_root_node(&fs_info->tree_root->root_item,
2467 fs_info->tree_root->node);
2468 list_add_tail(&fs_info->tree_root->dirty_list,
2469 &cur_trans->switch_commits);
2470
2471 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2472 fs_info->chunk_root->node);
2473 list_add_tail(&fs_info->chunk_root->dirty_list,
2474 &cur_trans->switch_commits);
2475
2476 if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2477 btrfs_set_root_node(&fs_info->block_group_root->root_item,
2478 fs_info->block_group_root->node);
2479 list_add_tail(&fs_info->block_group_root->dirty_list,
2480 &cur_trans->switch_commits);
2481 }
2482
2483 switch_commit_roots(trans);
2484
2485 ASSERT(list_empty(&cur_trans->dirty_bgs));
2486 ASSERT(list_empty(&cur_trans->io_bgs));
2487 update_super_roots(fs_info);
2488
2489 btrfs_set_super_log_root(fs_info->super_copy, 0);
2490 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2491 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2492 sizeof(*fs_info->super_copy));
2493
2494 btrfs_commit_device_sizes(cur_trans);
2495
2496 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2497 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2498
2499 btrfs_trans_release_chunk_metadata(trans);
2500
2501 /*
2502 * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2503 * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2504 * make sure that before we commit our superblock, no other task can
2505 * start a new transaction and commit a log tree before we commit our
2506 * superblock. Anyone trying to commit a log tree locks this mutex before
2507 * writing its superblock.
2508 */
2509 mutex_lock(&fs_info->tree_log_mutex);
2510
2511 spin_lock(&fs_info->trans_lock);
2512 cur_trans->state = TRANS_STATE_UNBLOCKED;
2513 fs_info->running_transaction = NULL;
2514 spin_unlock(&fs_info->trans_lock);
2515 mutex_unlock(&fs_info->reloc_mutex);
2516
2517 wake_up(&fs_info->transaction_wait);
2518 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2519
2520 /* If we have features changed, wake up the cleaner to update sysfs. */
2521 if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
2522 fs_info->cleaner_kthread)
2523 wake_up_process(fs_info->cleaner_kthread);
2524
2525 ret = btrfs_write_and_wait_transaction(trans);
2526 if (ret) {
2527 btrfs_handle_fs_error(fs_info, ret,
2528 "Error while writing out transaction");
2529 mutex_unlock(&fs_info->tree_log_mutex);
2530 goto scrub_continue;
2531 }
2532
2533 ret = write_all_supers(fs_info, 0);
2534 /*
2535 * the super is written, we can safely allow the tree-loggers
2536 * to go about their business
2537 */
2538 mutex_unlock(&fs_info->tree_log_mutex);
2539 if (ret)
2540 goto scrub_continue;
2541
2542 /*
2543 * We needn't acquire the lock here because there is no other task
2544 * which can change it.
2545 */
2546 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2547 wake_up(&cur_trans->commit_wait);
2548 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2549
2550 btrfs_finish_extent_commit(trans);
2551
2552 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2553 btrfs_clear_space_info_full(fs_info);
2554
2555 btrfs_set_last_trans_committed(fs_info, cur_trans->transid);
2556 /*
2557 * We needn't acquire the lock here because there is no other task
2558 * which can change it.
2559 */
2560 cur_trans->state = TRANS_STATE_COMPLETED;
2561 wake_up(&cur_trans->commit_wait);
2562 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2563
2564 spin_lock(&fs_info->trans_lock);
2565 list_del_init(&cur_trans->list);
2566 spin_unlock(&fs_info->trans_lock);
2567
2568 btrfs_put_transaction(cur_trans);
2569 btrfs_put_transaction(cur_trans);
2570
2571 if (trans->type & __TRANS_FREEZABLE)
2572 sb_end_intwrite(fs_info->sb);
2573
2574 trace_btrfs_transaction_commit(fs_info);
2575
2576 interval = ktime_get_ns() - start_time;
2577
2578 btrfs_scrub_continue(fs_info);
2579
2580 if (current->journal_info == trans)
2581 current->journal_info = NULL;
2582
2583 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2584
2585 update_commit_stats(fs_info, interval);
2586
2587 return ret;
2588
2589unlock_reloc:
2590 mutex_unlock(&fs_info->reloc_mutex);
2591 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2592scrub_continue:
2593 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2594 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2595 btrfs_scrub_continue(fs_info);
2596cleanup_transaction:
2597 btrfs_trans_release_metadata(trans);
2598 btrfs_cleanup_pending_block_groups(trans);
2599 btrfs_trans_release_chunk_metadata(trans);
2600 trans->block_rsv = NULL;
2601 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2602 if (current->journal_info == trans)
2603 current->journal_info = NULL;
2604 cleanup_transaction(trans, ret);
2605
2606 return ret;
2607
2608lockdep_release:
2609 btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2610 btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2611 goto cleanup_transaction;
2612
2613lockdep_trans_commit_start_release:
2614 btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_PREP);
2615 btrfs_end_transaction(trans);
2616 return ret;
2617}
2618
2619/*
2620 * return < 0 if error
2621 * 0 if there are no more dead_roots at the time of call
2622 * 1 there are more to be processed, call me again
2623 *
2624 * The return value indicates there are certainly more snapshots to delete, but
2625 * if there comes a new one during processing, it may return 0. We don't mind,
2626 * because btrfs_commit_super will poke cleaner thread and it will process it a
2627 * few seconds later.
2628 */
2629int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2630{
2631 struct btrfs_root *root;
2632 int ret;
2633
2634 spin_lock(&fs_info->trans_lock);
2635 if (list_empty(&fs_info->dead_roots)) {
2636 spin_unlock(&fs_info->trans_lock);
2637 return 0;
2638 }
2639 root = list_first_entry(&fs_info->dead_roots,
2640 struct btrfs_root, root_list);
2641 list_del_init(&root->root_list);
2642 spin_unlock(&fs_info->trans_lock);
2643
2644 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2645
2646 btrfs_kill_all_delayed_nodes(root);
2647
2648 if (btrfs_header_backref_rev(root->node) <
2649 BTRFS_MIXED_BACKREF_REV)
2650 ret = btrfs_drop_snapshot(root, 0, 0);
2651 else
2652 ret = btrfs_drop_snapshot(root, 1, 0);
2653
2654 btrfs_put_root(root);
2655 return (ret < 0) ? 0 : 1;
2656}
2657
2658/*
2659 * We only mark the transaction aborted and then set the file system read-only.
2660 * This will prevent new transactions from starting or trying to join this
2661 * one.
2662 *
2663 * This means that error recovery at the call site is limited to freeing
2664 * any local memory allocations and passing the error code up without
2665 * further cleanup. The transaction should complete as it normally would
2666 * in the call path but will return -EIO.
2667 *
2668 * We'll complete the cleanup in btrfs_end_transaction and
2669 * btrfs_commit_transaction.
2670 */
2671void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
2672 const char *function,
2673 unsigned int line, int error, bool first_hit)
2674{
2675 struct btrfs_fs_info *fs_info = trans->fs_info;
2676
2677 WRITE_ONCE(trans->aborted, error);
2678 WRITE_ONCE(trans->transaction->aborted, error);
2679 if (first_hit && error == -ENOSPC)
2680 btrfs_dump_space_info_for_trans_abort(fs_info);
2681 /* Wake up anybody who may be waiting on this transaction */
2682 wake_up(&fs_info->transaction_wait);
2683 wake_up(&fs_info->transaction_blocked_wait);
2684 __btrfs_handle_fs_error(fs_info, function, line, error, NULL);
2685}
2686
2687int __init btrfs_transaction_init(void)
2688{
2689 btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
2690 sizeof(struct btrfs_trans_handle), 0,
2691 SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
2692 if (!btrfs_trans_handle_cachep)
2693 return -ENOMEM;
2694 return 0;
2695}
2696
2697void __cold btrfs_transaction_exit(void)
2698{
2699 kmem_cache_destroy(btrfs_trans_handle_cachep);
2700}