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