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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2007 Oracle. All rights reserved.
4 */
5
6#include <linux/fs.h>
7#include <linux/slab.h>
8#include <linux/sched.h>
9#include <linux/writeback.h>
10#include <linux/pagemap.h>
11#include <linux/blkdev.h>
12#include <linux/uuid.h>
13#include "misc.h"
14#include "ctree.h"
15#include "disk-io.h"
16#include "transaction.h"
17#include "locking.h"
18#include "tree-log.h"
19#include "volumes.h"
20#include "dev-replace.h"
21#include "qgroup.h"
22#include "block-group.h"
23#include "space-info.h"
24#include "zoned.h"
25
26#define BTRFS_ROOT_TRANS_TAG 0
27
28/*
29 * Transaction states and transitions
30 *
31 * No running transaction (fs tree blocks are not modified)
32 * |
33 * | To next stage:
34 * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
35 * V
36 * Transaction N [[TRANS_STATE_RUNNING]]
37 * |
38 * | New trans handles can be attached to transaction N by calling all
39 * | start_transaction() variants.
40 * |
41 * | To next stage:
42 * | Call btrfs_commit_transaction() on any trans handle attached to
43 * | transaction N
44 * V
45 * Transaction N [[TRANS_STATE_COMMIT_START]]
46 * |
47 * | Will wait for previous running transaction to completely finish if there
48 * | is one
49 * |
50 * | Then one of the following happes:
51 * | - Wait for all other trans handle holders to release.
52 * | The btrfs_commit_transaction() caller will do the commit work.
53 * | - Wait for current transaction to be committed by others.
54 * | Other btrfs_commit_transaction() caller will do the commit work.
55 * |
56 * | At this stage, only btrfs_join_transaction*() variants can attach
57 * | to this running transaction.
58 * | All other variants will wait for current one to finish and attach to
59 * | transaction N+1.
60 * |
61 * | To next stage:
62 * | Caller is chosen to commit transaction N, and all other trans handle
63 * | haven been released.
64 * V
65 * Transaction N [[TRANS_STATE_COMMIT_DOING]]
66 * |
67 * | The heavy lifting transaction work is started.
68 * | From running delayed refs (modifying extent tree) to creating pending
69 * | snapshots, running qgroups.
70 * | In short, modify supporting trees to reflect modifications of subvolume
71 * | trees.
72 * |
73 * | At this stage, all start_transaction() calls will wait for this
74 * | transaction to finish and attach to transaction N+1.
75 * |
76 * | To next stage:
77 * | Until all supporting trees are updated.
78 * V
79 * Transaction N [[TRANS_STATE_UNBLOCKED]]
80 * | Transaction N+1
81 * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
82 * | need to write them back to disk and update |
83 * | super blocks. |
84 * | |
85 * | At this stage, new transaction is allowed to |
86 * | start. |
87 * | All new start_transaction() calls will be |
88 * | attached to transid N+1. |
89 * | |
90 * | To next stage: |
91 * | Until all tree blocks are super blocks are |
92 * | written to block devices |
93 * V |
94 * Transaction N [[TRANS_STATE_COMPLETED]] V
95 * All tree blocks and super blocks are written. Transaction N+1
96 * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
97 * data structures will be cleaned up. | Life goes on
98 */
99static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
100 [TRANS_STATE_RUNNING] = 0U,
101 [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
102 [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
103 __TRANS_ATTACH |
104 __TRANS_JOIN |
105 __TRANS_JOIN_NOSTART),
106 [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
107 __TRANS_ATTACH |
108 __TRANS_JOIN |
109 __TRANS_JOIN_NOLOCK |
110 __TRANS_JOIN_NOSTART),
111 [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
112 __TRANS_ATTACH |
113 __TRANS_JOIN |
114 __TRANS_JOIN_NOLOCK |
115 __TRANS_JOIN_NOSTART),
116 [TRANS_STATE_COMPLETED] = (__TRANS_START |
117 __TRANS_ATTACH |
118 __TRANS_JOIN |
119 __TRANS_JOIN_NOLOCK |
120 __TRANS_JOIN_NOSTART),
121};
122
123void btrfs_put_transaction(struct btrfs_transaction *transaction)
124{
125 WARN_ON(refcount_read(&transaction->use_count) == 0);
126 if (refcount_dec_and_test(&transaction->use_count)) {
127 BUG_ON(!list_empty(&transaction->list));
128 WARN_ON(!RB_EMPTY_ROOT(
129 &transaction->delayed_refs.href_root.rb_root));
130 WARN_ON(!RB_EMPTY_ROOT(
131 &transaction->delayed_refs.dirty_extent_root));
132 if (transaction->delayed_refs.pending_csums)
133 btrfs_err(transaction->fs_info,
134 "pending csums is %llu",
135 transaction->delayed_refs.pending_csums);
136 /*
137 * If any block groups are found in ->deleted_bgs then it's
138 * because the transaction was aborted and a commit did not
139 * happen (things failed before writing the new superblock
140 * and calling btrfs_finish_extent_commit()), so we can not
141 * discard the physical locations of the block groups.
142 */
143 while (!list_empty(&transaction->deleted_bgs)) {
144 struct btrfs_block_group *cache;
145
146 cache = list_first_entry(&transaction->deleted_bgs,
147 struct btrfs_block_group,
148 bg_list);
149 list_del_init(&cache->bg_list);
150 btrfs_unfreeze_block_group(cache);
151 btrfs_put_block_group(cache);
152 }
153 WARN_ON(!list_empty(&transaction->dev_update_list));
154 kfree(transaction);
155 }
156}
157
158static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
159{
160 struct btrfs_transaction *cur_trans = trans->transaction;
161 struct btrfs_fs_info *fs_info = trans->fs_info;
162 struct btrfs_root *root, *tmp;
163 struct btrfs_caching_control *caching_ctl, *next;
164
165 down_write(&fs_info->commit_root_sem);
166 list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
167 dirty_list) {
168 list_del_init(&root->dirty_list);
169 free_extent_buffer(root->commit_root);
170 root->commit_root = btrfs_root_node(root);
171 extent_io_tree_release(&root->dirty_log_pages);
172 btrfs_qgroup_clean_swapped_blocks(root);
173 }
174
175 /* We can free old roots now. */
176 spin_lock(&cur_trans->dropped_roots_lock);
177 while (!list_empty(&cur_trans->dropped_roots)) {
178 root = list_first_entry(&cur_trans->dropped_roots,
179 struct btrfs_root, root_list);
180 list_del_init(&root->root_list);
181 spin_unlock(&cur_trans->dropped_roots_lock);
182 btrfs_free_log(trans, root);
183 btrfs_drop_and_free_fs_root(fs_info, root);
184 spin_lock(&cur_trans->dropped_roots_lock);
185 }
186 spin_unlock(&cur_trans->dropped_roots_lock);
187
188 /*
189 * We have to update the last_byte_to_unpin under the commit_root_sem,
190 * at the same time we swap out the commit roots.
191 *
192 * This is because we must have a real view of the last spot the caching
193 * kthreads were while caching. Consider the following views of the
194 * extent tree for a block group
195 *
196 * commit root
197 * +----+----+----+----+----+----+----+
198 * |\\\\| |\\\\|\\\\| |\\\\|\\\\|
199 * +----+----+----+----+----+----+----+
200 * 0 1 2 3 4 5 6 7
201 *
202 * new commit root
203 * +----+----+----+----+----+----+----+
204 * | | | |\\\\| | |\\\\|
205 * +----+----+----+----+----+----+----+
206 * 0 1 2 3 4 5 6 7
207 *
208 * If the cache_ctl->progress was at 3, then we are only allowed to
209 * unpin [0,1) and [2,3], because the caching thread has already
210 * processed those extents. We are not allowed to unpin [5,6), because
211 * the caching thread will re-start it's search from 3, and thus find
212 * the hole from [4,6) to add to the free space cache.
213 */
214 spin_lock(&fs_info->block_group_cache_lock);
215 list_for_each_entry_safe(caching_ctl, next,
216 &fs_info->caching_block_groups, list) {
217 struct btrfs_block_group *cache = caching_ctl->block_group;
218
219 if (btrfs_block_group_done(cache)) {
220 cache->last_byte_to_unpin = (u64)-1;
221 list_del_init(&caching_ctl->list);
222 btrfs_put_caching_control(caching_ctl);
223 } else {
224 cache->last_byte_to_unpin = caching_ctl->progress;
225 }
226 }
227 spin_unlock(&fs_info->block_group_cache_lock);
228 up_write(&fs_info->commit_root_sem);
229}
230
231static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
232 unsigned int type)
233{
234 if (type & TRANS_EXTWRITERS)
235 atomic_inc(&trans->num_extwriters);
236}
237
238static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
239 unsigned int type)
240{
241 if (type & TRANS_EXTWRITERS)
242 atomic_dec(&trans->num_extwriters);
243}
244
245static inline void extwriter_counter_init(struct btrfs_transaction *trans,
246 unsigned int type)
247{
248 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
249}
250
251static inline int extwriter_counter_read(struct btrfs_transaction *trans)
252{
253 return atomic_read(&trans->num_extwriters);
254}
255
256/*
257 * To be called after doing the chunk btree updates right after allocating a new
258 * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
259 * chunk after all chunk btree updates and after finishing the second phase of
260 * chunk allocation (btrfs_create_pending_block_groups()) in case some block
261 * group had its chunk item insertion delayed to the second phase.
262 */
263void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
264{
265 struct btrfs_fs_info *fs_info = trans->fs_info;
266
267 if (!trans->chunk_bytes_reserved)
268 return;
269
270 btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
271 trans->chunk_bytes_reserved, NULL);
272 trans->chunk_bytes_reserved = 0;
273}
274
275/*
276 * either allocate a new transaction or hop into the existing one
277 */
278static noinline int join_transaction(struct btrfs_fs_info *fs_info,
279 unsigned int type)
280{
281 struct btrfs_transaction *cur_trans;
282
283 spin_lock(&fs_info->trans_lock);
284loop:
285 /* The file system has been taken offline. No new transactions. */
286 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
287 spin_unlock(&fs_info->trans_lock);
288 return -EROFS;
289 }
290
291 cur_trans = fs_info->running_transaction;
292 if (cur_trans) {
293 if (TRANS_ABORTED(cur_trans)) {
294 spin_unlock(&fs_info->trans_lock);
295 return cur_trans->aborted;
296 }
297 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
298 spin_unlock(&fs_info->trans_lock);
299 return -EBUSY;
300 }
301 refcount_inc(&cur_trans->use_count);
302 atomic_inc(&cur_trans->num_writers);
303 extwriter_counter_inc(cur_trans, type);
304 spin_unlock(&fs_info->trans_lock);
305 return 0;
306 }
307 spin_unlock(&fs_info->trans_lock);
308
309 /*
310 * If we are ATTACH, we just want to catch the current transaction,
311 * and commit it. If there is no transaction, just return ENOENT.
312 */
313 if (type == TRANS_ATTACH)
314 return -ENOENT;
315
316 /*
317 * JOIN_NOLOCK only happens during the transaction commit, so
318 * it is impossible that ->running_transaction is NULL
319 */
320 BUG_ON(type == TRANS_JOIN_NOLOCK);
321
322 cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
323 if (!cur_trans)
324 return -ENOMEM;
325
326 spin_lock(&fs_info->trans_lock);
327 if (fs_info->running_transaction) {
328 /*
329 * someone started a transaction after we unlocked. Make sure
330 * to redo the checks above
331 */
332 kfree(cur_trans);
333 goto loop;
334 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
335 spin_unlock(&fs_info->trans_lock);
336 kfree(cur_trans);
337 return -EROFS;
338 }
339
340 cur_trans->fs_info = fs_info;
341 atomic_set(&cur_trans->pending_ordered, 0);
342 init_waitqueue_head(&cur_trans->pending_wait);
343 atomic_set(&cur_trans->num_writers, 1);
344 extwriter_counter_init(cur_trans, type);
345 init_waitqueue_head(&cur_trans->writer_wait);
346 init_waitqueue_head(&cur_trans->commit_wait);
347 cur_trans->state = TRANS_STATE_RUNNING;
348 /*
349 * One for this trans handle, one so it will live on until we
350 * commit the transaction.
351 */
352 refcount_set(&cur_trans->use_count, 2);
353 cur_trans->flags = 0;
354 cur_trans->start_time = ktime_get_seconds();
355
356 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
357
358 cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
359 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
360 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
361
362 /*
363 * although the tree mod log is per file system and not per transaction,
364 * the log must never go across transaction boundaries.
365 */
366 smp_mb();
367 if (!list_empty(&fs_info->tree_mod_seq_list))
368 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
369 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
370 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
371 atomic64_set(&fs_info->tree_mod_seq, 0);
372
373 spin_lock_init(&cur_trans->delayed_refs.lock);
374
375 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
376 INIT_LIST_HEAD(&cur_trans->dev_update_list);
377 INIT_LIST_HEAD(&cur_trans->switch_commits);
378 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
379 INIT_LIST_HEAD(&cur_trans->io_bgs);
380 INIT_LIST_HEAD(&cur_trans->dropped_roots);
381 mutex_init(&cur_trans->cache_write_mutex);
382 spin_lock_init(&cur_trans->dirty_bgs_lock);
383 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
384 spin_lock_init(&cur_trans->dropped_roots_lock);
385 INIT_LIST_HEAD(&cur_trans->releasing_ebs);
386 spin_lock_init(&cur_trans->releasing_ebs_lock);
387 list_add_tail(&cur_trans->list, &fs_info->trans_list);
388 extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
389 IO_TREE_TRANS_DIRTY_PAGES, fs_info->btree_inode);
390 extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
391 IO_TREE_FS_PINNED_EXTENTS, NULL);
392 fs_info->generation++;
393 cur_trans->transid = fs_info->generation;
394 fs_info->running_transaction = cur_trans;
395 cur_trans->aborted = 0;
396 spin_unlock(&fs_info->trans_lock);
397
398 return 0;
399}
400
401/*
402 * This does all the record keeping required to make sure that a shareable root
403 * is properly recorded in a given transaction. This is required to make sure
404 * the old root from before we joined the transaction is deleted when the
405 * transaction commits.
406 */
407static int record_root_in_trans(struct btrfs_trans_handle *trans,
408 struct btrfs_root *root,
409 int force)
410{
411 struct btrfs_fs_info *fs_info = root->fs_info;
412 int ret = 0;
413
414 if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
415 root->last_trans < trans->transid) || force) {
416 WARN_ON(root == fs_info->extent_root);
417 WARN_ON(!force && root->commit_root != root->node);
418
419 /*
420 * see below for IN_TRANS_SETUP usage rules
421 * we have the reloc mutex held now, so there
422 * is only one writer in this function
423 */
424 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
425
426 /* make sure readers find IN_TRANS_SETUP before
427 * they find our root->last_trans update
428 */
429 smp_wmb();
430
431 spin_lock(&fs_info->fs_roots_radix_lock);
432 if (root->last_trans == trans->transid && !force) {
433 spin_unlock(&fs_info->fs_roots_radix_lock);
434 return 0;
435 }
436 radix_tree_tag_set(&fs_info->fs_roots_radix,
437 (unsigned long)root->root_key.objectid,
438 BTRFS_ROOT_TRANS_TAG);
439 spin_unlock(&fs_info->fs_roots_radix_lock);
440 root->last_trans = trans->transid;
441
442 /* this is pretty tricky. We don't want to
443 * take the relocation lock in btrfs_record_root_in_trans
444 * unless we're really doing the first setup for this root in
445 * this transaction.
446 *
447 * Normally we'd use root->last_trans as a flag to decide
448 * if we want to take the expensive mutex.
449 *
450 * But, we have to set root->last_trans before we
451 * init the relocation root, otherwise, we trip over warnings
452 * in ctree.c. The solution used here is to flag ourselves
453 * with root IN_TRANS_SETUP. When this is 1, we're still
454 * fixing up the reloc trees and everyone must wait.
455 *
456 * When this is zero, they can trust root->last_trans and fly
457 * through btrfs_record_root_in_trans without having to take the
458 * lock. smp_wmb() makes sure that all the writes above are
459 * done before we pop in the zero below
460 */
461 ret = btrfs_init_reloc_root(trans, root);
462 smp_mb__before_atomic();
463 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
464 }
465 return ret;
466}
467
468
469void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
470 struct btrfs_root *root)
471{
472 struct btrfs_fs_info *fs_info = root->fs_info;
473 struct btrfs_transaction *cur_trans = trans->transaction;
474
475 /* Add ourselves to the transaction dropped list */
476 spin_lock(&cur_trans->dropped_roots_lock);
477 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
478 spin_unlock(&cur_trans->dropped_roots_lock);
479
480 /* Make sure we don't try to update the root at commit time */
481 spin_lock(&fs_info->fs_roots_radix_lock);
482 radix_tree_tag_clear(&fs_info->fs_roots_radix,
483 (unsigned long)root->root_key.objectid,
484 BTRFS_ROOT_TRANS_TAG);
485 spin_unlock(&fs_info->fs_roots_radix_lock);
486}
487
488int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
489 struct btrfs_root *root)
490{
491 struct btrfs_fs_info *fs_info = root->fs_info;
492 int ret;
493
494 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
495 return 0;
496
497 /*
498 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
499 * and barriers
500 */
501 smp_rmb();
502 if (root->last_trans == trans->transid &&
503 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
504 return 0;
505
506 mutex_lock(&fs_info->reloc_mutex);
507 ret = record_root_in_trans(trans, root, 0);
508 mutex_unlock(&fs_info->reloc_mutex);
509
510 return ret;
511}
512
513static inline int is_transaction_blocked(struct btrfs_transaction *trans)
514{
515 return (trans->state >= TRANS_STATE_COMMIT_START &&
516 trans->state < TRANS_STATE_UNBLOCKED &&
517 !TRANS_ABORTED(trans));
518}
519
520/* wait for commit against the current transaction to become unblocked
521 * when this is done, it is safe to start a new transaction, but the current
522 * transaction might not be fully on disk.
523 */
524static void wait_current_trans(struct btrfs_fs_info *fs_info)
525{
526 struct btrfs_transaction *cur_trans;
527
528 spin_lock(&fs_info->trans_lock);
529 cur_trans = fs_info->running_transaction;
530 if (cur_trans && is_transaction_blocked(cur_trans)) {
531 refcount_inc(&cur_trans->use_count);
532 spin_unlock(&fs_info->trans_lock);
533
534 wait_event(fs_info->transaction_wait,
535 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
536 TRANS_ABORTED(cur_trans));
537 btrfs_put_transaction(cur_trans);
538 } else {
539 spin_unlock(&fs_info->trans_lock);
540 }
541}
542
543static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
544{
545 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
546 return 0;
547
548 if (type == TRANS_START)
549 return 1;
550
551 return 0;
552}
553
554static inline bool need_reserve_reloc_root(struct btrfs_root *root)
555{
556 struct btrfs_fs_info *fs_info = root->fs_info;
557
558 if (!fs_info->reloc_ctl ||
559 !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
560 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
561 root->reloc_root)
562 return false;
563
564 return true;
565}
566
567static struct btrfs_trans_handle *
568start_transaction(struct btrfs_root *root, unsigned int num_items,
569 unsigned int type, enum btrfs_reserve_flush_enum flush,
570 bool enforce_qgroups)
571{
572 struct btrfs_fs_info *fs_info = root->fs_info;
573 struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
574 struct btrfs_trans_handle *h;
575 struct btrfs_transaction *cur_trans;
576 u64 num_bytes = 0;
577 u64 qgroup_reserved = 0;
578 bool reloc_reserved = false;
579 bool do_chunk_alloc = false;
580 int ret;
581
582 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
583 return ERR_PTR(-EROFS);
584
585 if (current->journal_info) {
586 WARN_ON(type & TRANS_EXTWRITERS);
587 h = current->journal_info;
588 refcount_inc(&h->use_count);
589 WARN_ON(refcount_read(&h->use_count) > 2);
590 h->orig_rsv = h->block_rsv;
591 h->block_rsv = NULL;
592 goto got_it;
593 }
594
595 /*
596 * Do the reservation before we join the transaction so we can do all
597 * the appropriate flushing if need be.
598 */
599 if (num_items && root != fs_info->chunk_root) {
600 struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
601 u64 delayed_refs_bytes = 0;
602
603 qgroup_reserved = num_items * fs_info->nodesize;
604 ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
605 enforce_qgroups);
606 if (ret)
607 return ERR_PTR(ret);
608
609 /*
610 * We want to reserve all the bytes we may need all at once, so
611 * we only do 1 enospc flushing cycle per transaction start. We
612 * accomplish this by simply assuming we'll do 2 x num_items
613 * worth of delayed refs updates in this trans handle, and
614 * refill that amount for whatever is missing in the reserve.
615 */
616 num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
617 if (flush == BTRFS_RESERVE_FLUSH_ALL &&
618 delayed_refs_rsv->full == 0) {
619 delayed_refs_bytes = num_bytes;
620 num_bytes <<= 1;
621 }
622
623 /*
624 * Do the reservation for the relocation root creation
625 */
626 if (need_reserve_reloc_root(root)) {
627 num_bytes += fs_info->nodesize;
628 reloc_reserved = true;
629 }
630
631 ret = btrfs_block_rsv_add(root, rsv, num_bytes, flush);
632 if (ret)
633 goto reserve_fail;
634 if (delayed_refs_bytes) {
635 btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
636 delayed_refs_bytes);
637 num_bytes -= delayed_refs_bytes;
638 }
639
640 if (rsv->space_info->force_alloc)
641 do_chunk_alloc = true;
642 } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
643 !delayed_refs_rsv->full) {
644 /*
645 * Some people call with btrfs_start_transaction(root, 0)
646 * because they can be throttled, but have some other mechanism
647 * for reserving space. We still want these guys to refill the
648 * delayed block_rsv so just add 1 items worth of reservation
649 * here.
650 */
651 ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
652 if (ret)
653 goto reserve_fail;
654 }
655again:
656 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
657 if (!h) {
658 ret = -ENOMEM;
659 goto alloc_fail;
660 }
661
662 /*
663 * If we are JOIN_NOLOCK we're already committing a transaction and
664 * waiting on this guy, so we don't need to do the sb_start_intwrite
665 * because we're already holding a ref. We need this because we could
666 * have raced in and did an fsync() on a file which can kick a commit
667 * and then we deadlock with somebody doing a freeze.
668 *
669 * If we are ATTACH, it means we just want to catch the current
670 * transaction and commit it, so we needn't do sb_start_intwrite().
671 */
672 if (type & __TRANS_FREEZABLE)
673 sb_start_intwrite(fs_info->sb);
674
675 if (may_wait_transaction(fs_info, type))
676 wait_current_trans(fs_info);
677
678 do {
679 ret = join_transaction(fs_info, type);
680 if (ret == -EBUSY) {
681 wait_current_trans(fs_info);
682 if (unlikely(type == TRANS_ATTACH ||
683 type == TRANS_JOIN_NOSTART))
684 ret = -ENOENT;
685 }
686 } while (ret == -EBUSY);
687
688 if (ret < 0)
689 goto join_fail;
690
691 cur_trans = fs_info->running_transaction;
692
693 h->transid = cur_trans->transid;
694 h->transaction = cur_trans;
695 h->root = root;
696 refcount_set(&h->use_count, 1);
697 h->fs_info = root->fs_info;
698
699 h->type = type;
700 INIT_LIST_HEAD(&h->new_bgs);
701
702 smp_mb();
703 if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
704 may_wait_transaction(fs_info, type)) {
705 current->journal_info = h;
706 btrfs_commit_transaction(h);
707 goto again;
708 }
709
710 if (num_bytes) {
711 trace_btrfs_space_reservation(fs_info, "transaction",
712 h->transid, num_bytes, 1);
713 h->block_rsv = &fs_info->trans_block_rsv;
714 h->bytes_reserved = num_bytes;
715 h->reloc_reserved = reloc_reserved;
716 }
717
718got_it:
719 if (!current->journal_info)
720 current->journal_info = h;
721
722 /*
723 * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
724 * ALLOC_FORCE the first run through, and then we won't allocate for
725 * anybody else who races in later. We don't care about the return
726 * value here.
727 */
728 if (do_chunk_alloc && num_bytes) {
729 u64 flags = h->block_rsv->space_info->flags;
730
731 btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
732 CHUNK_ALLOC_NO_FORCE);
733 }
734
735 /*
736 * btrfs_record_root_in_trans() needs to alloc new extents, and may
737 * call btrfs_join_transaction() while we're also starting a
738 * transaction.
739 *
740 * Thus it need to be called after current->journal_info initialized,
741 * or we can deadlock.
742 */
743 ret = btrfs_record_root_in_trans(h, root);
744 if (ret) {
745 /*
746 * The transaction handle is fully initialized and linked with
747 * other structures so it needs to be ended in case of errors,
748 * not just freed.
749 */
750 btrfs_end_transaction(h);
751 return ERR_PTR(ret);
752 }
753
754 return h;
755
756join_fail:
757 if (type & __TRANS_FREEZABLE)
758 sb_end_intwrite(fs_info->sb);
759 kmem_cache_free(btrfs_trans_handle_cachep, h);
760alloc_fail:
761 if (num_bytes)
762 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
763 num_bytes, NULL);
764reserve_fail:
765 btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
766 return ERR_PTR(ret);
767}
768
769struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
770 unsigned int num_items)
771{
772 return start_transaction(root, num_items, TRANS_START,
773 BTRFS_RESERVE_FLUSH_ALL, true);
774}
775
776struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
777 struct btrfs_root *root,
778 unsigned int num_items)
779{
780 return start_transaction(root, num_items, TRANS_START,
781 BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
782}
783
784struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
785{
786 return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
787 true);
788}
789
790struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
791{
792 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
793 BTRFS_RESERVE_NO_FLUSH, true);
794}
795
796/*
797 * Similar to regular join but it never starts a transaction when none is
798 * running or after waiting for the current one to finish.
799 */
800struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
801{
802 return start_transaction(root, 0, TRANS_JOIN_NOSTART,
803 BTRFS_RESERVE_NO_FLUSH, true);
804}
805
806/*
807 * btrfs_attach_transaction() - catch the running transaction
808 *
809 * It is used when we want to commit the current the transaction, but
810 * don't want to start a new one.
811 *
812 * Note: If this function return -ENOENT, it just means there is no
813 * running transaction. But it is possible that the inactive transaction
814 * is still in the memory, not fully on disk. If you hope there is no
815 * inactive transaction in the fs when -ENOENT is returned, you should
816 * invoke
817 * btrfs_attach_transaction_barrier()
818 */
819struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
820{
821 return start_transaction(root, 0, TRANS_ATTACH,
822 BTRFS_RESERVE_NO_FLUSH, true);
823}
824
825/*
826 * btrfs_attach_transaction_barrier() - catch the running transaction
827 *
828 * It is similar to the above function, the difference is this one
829 * will wait for all the inactive transactions until they fully
830 * complete.
831 */
832struct btrfs_trans_handle *
833btrfs_attach_transaction_barrier(struct btrfs_root *root)
834{
835 struct btrfs_trans_handle *trans;
836
837 trans = start_transaction(root, 0, TRANS_ATTACH,
838 BTRFS_RESERVE_NO_FLUSH, true);
839 if (trans == ERR_PTR(-ENOENT))
840 btrfs_wait_for_commit(root->fs_info, 0);
841
842 return trans;
843}
844
845/* Wait for a transaction commit to reach at least the given state. */
846static noinline void wait_for_commit(struct btrfs_transaction *commit,
847 const enum btrfs_trans_state min_state)
848{
849 wait_event(commit->commit_wait, commit->state >= min_state);
850}
851
852int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
853{
854 struct btrfs_transaction *cur_trans = NULL, *t;
855 int ret = 0;
856
857 if (transid) {
858 if (transid <= fs_info->last_trans_committed)
859 goto out;
860
861 /* find specified transaction */
862 spin_lock(&fs_info->trans_lock);
863 list_for_each_entry(t, &fs_info->trans_list, list) {
864 if (t->transid == transid) {
865 cur_trans = t;
866 refcount_inc(&cur_trans->use_count);
867 ret = 0;
868 break;
869 }
870 if (t->transid > transid) {
871 ret = 0;
872 break;
873 }
874 }
875 spin_unlock(&fs_info->trans_lock);
876
877 /*
878 * The specified transaction doesn't exist, or we
879 * raced with btrfs_commit_transaction
880 */
881 if (!cur_trans) {
882 if (transid > fs_info->last_trans_committed)
883 ret = -EINVAL;
884 goto out;
885 }
886 } else {
887 /* find newest transaction that is committing | committed */
888 spin_lock(&fs_info->trans_lock);
889 list_for_each_entry_reverse(t, &fs_info->trans_list,
890 list) {
891 if (t->state >= TRANS_STATE_COMMIT_START) {
892 if (t->state == TRANS_STATE_COMPLETED)
893 break;
894 cur_trans = t;
895 refcount_inc(&cur_trans->use_count);
896 break;
897 }
898 }
899 spin_unlock(&fs_info->trans_lock);
900 if (!cur_trans)
901 goto out; /* nothing committing|committed */
902 }
903
904 wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
905 btrfs_put_transaction(cur_trans);
906out:
907 return ret;
908}
909
910void btrfs_throttle(struct btrfs_fs_info *fs_info)
911{
912 wait_current_trans(fs_info);
913}
914
915static bool should_end_transaction(struct btrfs_trans_handle *trans)
916{
917 struct btrfs_fs_info *fs_info = trans->fs_info;
918
919 if (btrfs_check_space_for_delayed_refs(fs_info))
920 return true;
921
922 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
923}
924
925bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
926{
927 struct btrfs_transaction *cur_trans = trans->transaction;
928
929 if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
930 test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
931 return true;
932
933 return should_end_transaction(trans);
934}
935
936static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
937
938{
939 struct btrfs_fs_info *fs_info = trans->fs_info;
940
941 if (!trans->block_rsv) {
942 ASSERT(!trans->bytes_reserved);
943 return;
944 }
945
946 if (!trans->bytes_reserved)
947 return;
948
949 ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
950 trace_btrfs_space_reservation(fs_info, "transaction",
951 trans->transid, trans->bytes_reserved, 0);
952 btrfs_block_rsv_release(fs_info, trans->block_rsv,
953 trans->bytes_reserved, NULL);
954 trans->bytes_reserved = 0;
955}
956
957static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
958 int throttle)
959{
960 struct btrfs_fs_info *info = trans->fs_info;
961 struct btrfs_transaction *cur_trans = trans->transaction;
962 int err = 0;
963
964 if (refcount_read(&trans->use_count) > 1) {
965 refcount_dec(&trans->use_count);
966 trans->block_rsv = trans->orig_rsv;
967 return 0;
968 }
969
970 btrfs_trans_release_metadata(trans);
971 trans->block_rsv = NULL;
972
973 btrfs_create_pending_block_groups(trans);
974
975 btrfs_trans_release_chunk_metadata(trans);
976
977 if (trans->type & __TRANS_FREEZABLE)
978 sb_end_intwrite(info->sb);
979
980 WARN_ON(cur_trans != info->running_transaction);
981 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
982 atomic_dec(&cur_trans->num_writers);
983 extwriter_counter_dec(cur_trans, trans->type);
984
985 cond_wake_up(&cur_trans->writer_wait);
986 btrfs_put_transaction(cur_trans);
987
988 if (current->journal_info == trans)
989 current->journal_info = NULL;
990
991 if (throttle)
992 btrfs_run_delayed_iputs(info);
993
994 if (TRANS_ABORTED(trans) ||
995 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
996 wake_up_process(info->transaction_kthread);
997 if (TRANS_ABORTED(trans))
998 err = trans->aborted;
999 else
1000 err = -EROFS;
1001 }
1002
1003 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1004 return err;
1005}
1006
1007int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1008{
1009 return __btrfs_end_transaction(trans, 0);
1010}
1011
1012int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1013{
1014 return __btrfs_end_transaction(trans, 1);
1015}
1016
1017/*
1018 * when btree blocks are allocated, they have some corresponding bits set for
1019 * them in one of two extent_io trees. This is used to make sure all of
1020 * those extents are sent to disk but does not wait on them
1021 */
1022int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1023 struct extent_io_tree *dirty_pages, int mark)
1024{
1025 int err = 0;
1026 int werr = 0;
1027 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1028 struct extent_state *cached_state = NULL;
1029 u64 start = 0;
1030 u64 end;
1031
1032 atomic_inc(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1033 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1034 mark, &cached_state)) {
1035 bool wait_writeback = false;
1036
1037 err = convert_extent_bit(dirty_pages, start, end,
1038 EXTENT_NEED_WAIT,
1039 mark, &cached_state);
1040 /*
1041 * convert_extent_bit can return -ENOMEM, which is most of the
1042 * time a temporary error. So when it happens, ignore the error
1043 * and wait for writeback of this range to finish - because we
1044 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1045 * to __btrfs_wait_marked_extents() would not know that
1046 * writeback for this range started and therefore wouldn't
1047 * wait for it to finish - we don't want to commit a
1048 * superblock that points to btree nodes/leafs for which
1049 * writeback hasn't finished yet (and without errors).
1050 * We cleanup any entries left in the io tree when committing
1051 * the transaction (through extent_io_tree_release()).
1052 */
1053 if (err == -ENOMEM) {
1054 err = 0;
1055 wait_writeback = true;
1056 }
1057 if (!err)
1058 err = filemap_fdatawrite_range(mapping, start, end);
1059 if (err)
1060 werr = err;
1061 else if (wait_writeback)
1062 werr = filemap_fdatawait_range(mapping, start, end);
1063 free_extent_state(cached_state);
1064 cached_state = NULL;
1065 cond_resched();
1066 start = end + 1;
1067 }
1068 atomic_dec(&BTRFS_I(fs_info->btree_inode)->sync_writers);
1069 return werr;
1070}
1071
1072/*
1073 * when btree blocks are allocated, they have some corresponding bits set for
1074 * them in one of two extent_io trees. This is used to make sure all of
1075 * those extents are on disk for transaction or log commit. We wait
1076 * on all the pages and clear them from the dirty pages state tree
1077 */
1078static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1079 struct extent_io_tree *dirty_pages)
1080{
1081 int err = 0;
1082 int werr = 0;
1083 struct address_space *mapping = fs_info->btree_inode->i_mapping;
1084 struct extent_state *cached_state = NULL;
1085 u64 start = 0;
1086 u64 end;
1087
1088 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1089 EXTENT_NEED_WAIT, &cached_state)) {
1090 /*
1091 * Ignore -ENOMEM errors returned by clear_extent_bit().
1092 * When committing the transaction, we'll remove any entries
1093 * left in the io tree. For a log commit, we don't remove them
1094 * after committing the log because the tree can be accessed
1095 * concurrently - we do it only at transaction commit time when
1096 * it's safe to do it (through extent_io_tree_release()).
1097 */
1098 err = clear_extent_bit(dirty_pages, start, end,
1099 EXTENT_NEED_WAIT, 0, 0, &cached_state);
1100 if (err == -ENOMEM)
1101 err = 0;
1102 if (!err)
1103 err = filemap_fdatawait_range(mapping, start, end);
1104 if (err)
1105 werr = err;
1106 free_extent_state(cached_state);
1107 cached_state = NULL;
1108 cond_resched();
1109 start = end + 1;
1110 }
1111 if (err)
1112 werr = err;
1113 return werr;
1114}
1115
1116static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1117 struct extent_io_tree *dirty_pages)
1118{
1119 bool errors = false;
1120 int err;
1121
1122 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1123 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1124 errors = true;
1125
1126 if (errors && !err)
1127 err = -EIO;
1128 return err;
1129}
1130
1131int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1132{
1133 struct btrfs_fs_info *fs_info = log_root->fs_info;
1134 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1135 bool errors = false;
1136 int err;
1137
1138 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1139
1140 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1141 if ((mark & EXTENT_DIRTY) &&
1142 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1143 errors = true;
1144
1145 if ((mark & EXTENT_NEW) &&
1146 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1147 errors = true;
1148
1149 if (errors && !err)
1150 err = -EIO;
1151 return err;
1152}
1153
1154/*
1155 * When btree blocks are allocated the corresponding extents are marked dirty.
1156 * This function ensures such extents are persisted on disk for transaction or
1157 * log commit.
1158 *
1159 * @trans: transaction whose dirty pages we'd like to write
1160 */
1161static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1162{
1163 int ret;
1164 int ret2;
1165 struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1166 struct btrfs_fs_info *fs_info = trans->fs_info;
1167 struct blk_plug plug;
1168
1169 blk_start_plug(&plug);
1170 ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1171 blk_finish_plug(&plug);
1172 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1173
1174 extent_io_tree_release(&trans->transaction->dirty_pages);
1175
1176 if (ret)
1177 return ret;
1178 else if (ret2)
1179 return ret2;
1180 else
1181 return 0;
1182}
1183
1184/*
1185 * this is used to update the root pointer in the tree of tree roots.
1186 *
1187 * But, in the case of the extent allocation tree, updating the root
1188 * pointer may allocate blocks which may change the root of the extent
1189 * allocation tree.
1190 *
1191 * So, this loops and repeats and makes sure the cowonly root didn't
1192 * change while the root pointer was being updated in the metadata.
1193 */
1194static int update_cowonly_root(struct btrfs_trans_handle *trans,
1195 struct btrfs_root *root)
1196{
1197 int ret;
1198 u64 old_root_bytenr;
1199 u64 old_root_used;
1200 struct btrfs_fs_info *fs_info = root->fs_info;
1201 struct btrfs_root *tree_root = fs_info->tree_root;
1202
1203 old_root_used = btrfs_root_used(&root->root_item);
1204
1205 while (1) {
1206 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1207 if (old_root_bytenr == root->node->start &&
1208 old_root_used == btrfs_root_used(&root->root_item))
1209 break;
1210
1211 btrfs_set_root_node(&root->root_item, root->node);
1212 ret = btrfs_update_root(trans, tree_root,
1213 &root->root_key,
1214 &root->root_item);
1215 if (ret)
1216 return ret;
1217
1218 old_root_used = btrfs_root_used(&root->root_item);
1219 }
1220
1221 return 0;
1222}
1223
1224/*
1225 * update all the cowonly tree roots on disk
1226 *
1227 * The error handling in this function may not be obvious. Any of the
1228 * failures will cause the file system to go offline. We still need
1229 * to clean up the delayed refs.
1230 */
1231static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1232{
1233 struct btrfs_fs_info *fs_info = trans->fs_info;
1234 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1235 struct list_head *io_bgs = &trans->transaction->io_bgs;
1236 struct list_head *next;
1237 struct extent_buffer *eb;
1238 int ret;
1239
1240 eb = btrfs_lock_root_node(fs_info->tree_root);
1241 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1242 0, &eb, BTRFS_NESTING_COW);
1243 btrfs_tree_unlock(eb);
1244 free_extent_buffer(eb);
1245
1246 if (ret)
1247 return ret;
1248
1249 ret = btrfs_run_dev_stats(trans);
1250 if (ret)
1251 return ret;
1252 ret = btrfs_run_dev_replace(trans);
1253 if (ret)
1254 return ret;
1255 ret = btrfs_run_qgroups(trans);
1256 if (ret)
1257 return ret;
1258
1259 ret = btrfs_setup_space_cache(trans);
1260 if (ret)
1261 return ret;
1262
1263again:
1264 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1265 struct btrfs_root *root;
1266 next = fs_info->dirty_cowonly_roots.next;
1267 list_del_init(next);
1268 root = list_entry(next, struct btrfs_root, dirty_list);
1269 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1270
1271 if (root != fs_info->extent_root)
1272 list_add_tail(&root->dirty_list,
1273 &trans->transaction->switch_commits);
1274 ret = update_cowonly_root(trans, root);
1275 if (ret)
1276 return ret;
1277 }
1278
1279 /* Now flush any delayed refs generated by updating all of the roots */
1280 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1281 if (ret)
1282 return ret;
1283
1284 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1285 ret = btrfs_write_dirty_block_groups(trans);
1286 if (ret)
1287 return ret;
1288
1289 /*
1290 * We're writing the dirty block groups, which could generate
1291 * delayed refs, which could generate more dirty block groups,
1292 * so we want to keep this flushing in this loop to make sure
1293 * everything gets run.
1294 */
1295 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1296 if (ret)
1297 return ret;
1298 }
1299
1300 if (!list_empty(&fs_info->dirty_cowonly_roots))
1301 goto again;
1302
1303 list_add_tail(&fs_info->extent_root->dirty_list,
1304 &trans->transaction->switch_commits);
1305
1306 /* Update dev-replace pointer once everything is committed */
1307 fs_info->dev_replace.committed_cursor_left =
1308 fs_info->dev_replace.cursor_left_last_write_of_item;
1309
1310 return 0;
1311}
1312
1313/*
1314 * dead roots are old snapshots that need to be deleted. This allocates
1315 * a dirty root struct and adds it into the list of dead roots that need to
1316 * be deleted
1317 */
1318void btrfs_add_dead_root(struct btrfs_root *root)
1319{
1320 struct btrfs_fs_info *fs_info = root->fs_info;
1321
1322 spin_lock(&fs_info->trans_lock);
1323 if (list_empty(&root->root_list)) {
1324 btrfs_grab_root(root);
1325 list_add_tail(&root->root_list, &fs_info->dead_roots);
1326 }
1327 spin_unlock(&fs_info->trans_lock);
1328}
1329
1330/*
1331 * update all the cowonly tree roots on disk
1332 */
1333static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1334{
1335 struct btrfs_fs_info *fs_info = trans->fs_info;
1336 struct btrfs_root *gang[8];
1337 int i;
1338 int ret;
1339
1340 spin_lock(&fs_info->fs_roots_radix_lock);
1341 while (1) {
1342 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1343 (void **)gang, 0,
1344 ARRAY_SIZE(gang),
1345 BTRFS_ROOT_TRANS_TAG);
1346 if (ret == 0)
1347 break;
1348 for (i = 0; i < ret; i++) {
1349 struct btrfs_root *root = gang[i];
1350 int ret2;
1351
1352 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1353 (unsigned long)root->root_key.objectid,
1354 BTRFS_ROOT_TRANS_TAG);
1355 spin_unlock(&fs_info->fs_roots_radix_lock);
1356
1357 btrfs_free_log(trans, root);
1358 ret2 = btrfs_update_reloc_root(trans, root);
1359 if (ret2)
1360 return ret2;
1361
1362 /* see comments in should_cow_block() */
1363 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1364 smp_mb__after_atomic();
1365
1366 if (root->commit_root != root->node) {
1367 list_add_tail(&root->dirty_list,
1368 &trans->transaction->switch_commits);
1369 btrfs_set_root_node(&root->root_item,
1370 root->node);
1371 }
1372
1373 ret2 = btrfs_update_root(trans, fs_info->tree_root,
1374 &root->root_key,
1375 &root->root_item);
1376 if (ret2)
1377 return ret2;
1378 spin_lock(&fs_info->fs_roots_radix_lock);
1379 btrfs_qgroup_free_meta_all_pertrans(root);
1380 }
1381 }
1382 spin_unlock(&fs_info->fs_roots_radix_lock);
1383 return 0;
1384}
1385
1386/*
1387 * defrag a given btree.
1388 * Every leaf in the btree is read and defragged.
1389 */
1390int btrfs_defrag_root(struct btrfs_root *root)
1391{
1392 struct btrfs_fs_info *info = root->fs_info;
1393 struct btrfs_trans_handle *trans;
1394 int ret;
1395
1396 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1397 return 0;
1398
1399 while (1) {
1400 trans = btrfs_start_transaction(root, 0);
1401 if (IS_ERR(trans)) {
1402 ret = PTR_ERR(trans);
1403 break;
1404 }
1405
1406 ret = btrfs_defrag_leaves(trans, root);
1407
1408 btrfs_end_transaction(trans);
1409 btrfs_btree_balance_dirty(info);
1410 cond_resched();
1411
1412 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1413 break;
1414
1415 if (btrfs_defrag_cancelled(info)) {
1416 btrfs_debug(info, "defrag_root cancelled");
1417 ret = -EAGAIN;
1418 break;
1419 }
1420 }
1421 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1422 return ret;
1423}
1424
1425/*
1426 * Do all special snapshot related qgroup dirty hack.
1427 *
1428 * Will do all needed qgroup inherit and dirty hack like switch commit
1429 * roots inside one transaction and write all btree into disk, to make
1430 * qgroup works.
1431 */
1432static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1433 struct btrfs_root *src,
1434 struct btrfs_root *parent,
1435 struct btrfs_qgroup_inherit *inherit,
1436 u64 dst_objectid)
1437{
1438 struct btrfs_fs_info *fs_info = src->fs_info;
1439 int ret;
1440
1441 /*
1442 * Save some performance in the case that qgroups are not
1443 * enabled. If this check races with the ioctl, rescan will
1444 * kick in anyway.
1445 */
1446 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1447 return 0;
1448
1449 /*
1450 * Ensure dirty @src will be committed. Or, after coming
1451 * commit_fs_roots() and switch_commit_roots(), any dirty but not
1452 * recorded root will never be updated again, causing an outdated root
1453 * item.
1454 */
1455 ret = record_root_in_trans(trans, src, 1);
1456 if (ret)
1457 return ret;
1458
1459 /*
1460 * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1461 * src root, so we must run the delayed refs here.
1462 *
1463 * However this isn't particularly fool proof, because there's no
1464 * synchronization keeping us from changing the tree after this point
1465 * before we do the qgroup_inherit, or even from making changes while
1466 * we're doing the qgroup_inherit. But that's a problem for the future,
1467 * for now flush the delayed refs to narrow the race window where the
1468 * qgroup counters could end up wrong.
1469 */
1470 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1471 if (ret) {
1472 btrfs_abort_transaction(trans, ret);
1473 return ret;
1474 }
1475
1476 /*
1477 * We are going to commit transaction, see btrfs_commit_transaction()
1478 * comment for reason locking tree_log_mutex
1479 */
1480 mutex_lock(&fs_info->tree_log_mutex);
1481
1482 ret = commit_fs_roots(trans);
1483 if (ret)
1484 goto out;
1485 ret = btrfs_qgroup_account_extents(trans);
1486 if (ret < 0)
1487 goto out;
1488
1489 /* Now qgroup are all updated, we can inherit it to new qgroups */
1490 ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1491 inherit);
1492 if (ret < 0)
1493 goto out;
1494
1495 /*
1496 * Now we do a simplified commit transaction, which will:
1497 * 1) commit all subvolume and extent tree
1498 * To ensure all subvolume and extent tree have a valid
1499 * commit_root to accounting later insert_dir_item()
1500 * 2) write all btree blocks onto disk
1501 * This is to make sure later btree modification will be cowed
1502 * Or commit_root can be populated and cause wrong qgroup numbers
1503 * In this simplified commit, we don't really care about other trees
1504 * like chunk and root tree, as they won't affect qgroup.
1505 * And we don't write super to avoid half committed status.
1506 */
1507 ret = commit_cowonly_roots(trans);
1508 if (ret)
1509 goto out;
1510 switch_commit_roots(trans);
1511 ret = btrfs_write_and_wait_transaction(trans);
1512 if (ret)
1513 btrfs_handle_fs_error(fs_info, ret,
1514 "Error while writing out transaction for qgroup");
1515
1516out:
1517 mutex_unlock(&fs_info->tree_log_mutex);
1518
1519 /*
1520 * Force parent root to be updated, as we recorded it before so its
1521 * last_trans == cur_transid.
1522 * Or it won't be committed again onto disk after later
1523 * insert_dir_item()
1524 */
1525 if (!ret)
1526 ret = record_root_in_trans(trans, parent, 1);
1527 return ret;
1528}
1529
1530/*
1531 * new snapshots need to be created at a very specific time in the
1532 * transaction commit. This does the actual creation.
1533 *
1534 * Note:
1535 * If the error which may affect the commitment of the current transaction
1536 * happens, we should return the error number. If the error which just affect
1537 * the creation of the pending snapshots, just return 0.
1538 */
1539static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1540 struct btrfs_pending_snapshot *pending)
1541{
1542
1543 struct btrfs_fs_info *fs_info = trans->fs_info;
1544 struct btrfs_key key;
1545 struct btrfs_root_item *new_root_item;
1546 struct btrfs_root *tree_root = fs_info->tree_root;
1547 struct btrfs_root *root = pending->root;
1548 struct btrfs_root *parent_root;
1549 struct btrfs_block_rsv *rsv;
1550 struct inode *parent_inode;
1551 struct btrfs_path *path;
1552 struct btrfs_dir_item *dir_item;
1553 struct dentry *dentry;
1554 struct extent_buffer *tmp;
1555 struct extent_buffer *old;
1556 struct timespec64 cur_time;
1557 int ret = 0;
1558 u64 to_reserve = 0;
1559 u64 index = 0;
1560 u64 objectid;
1561 u64 root_flags;
1562
1563 ASSERT(pending->path);
1564 path = pending->path;
1565
1566 ASSERT(pending->root_item);
1567 new_root_item = pending->root_item;
1568
1569 pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1570 if (pending->error)
1571 goto no_free_objectid;
1572
1573 /*
1574 * Make qgroup to skip current new snapshot's qgroupid, as it is
1575 * accounted by later btrfs_qgroup_inherit().
1576 */
1577 btrfs_set_skip_qgroup(trans, objectid);
1578
1579 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1580
1581 if (to_reserve > 0) {
1582 pending->error = btrfs_block_rsv_add(root,
1583 &pending->block_rsv,
1584 to_reserve,
1585 BTRFS_RESERVE_NO_FLUSH);
1586 if (pending->error)
1587 goto clear_skip_qgroup;
1588 }
1589
1590 key.objectid = objectid;
1591 key.offset = (u64)-1;
1592 key.type = BTRFS_ROOT_ITEM_KEY;
1593
1594 rsv = trans->block_rsv;
1595 trans->block_rsv = &pending->block_rsv;
1596 trans->bytes_reserved = trans->block_rsv->reserved;
1597 trace_btrfs_space_reservation(fs_info, "transaction",
1598 trans->transid,
1599 trans->bytes_reserved, 1);
1600 dentry = pending->dentry;
1601 parent_inode = pending->dir;
1602 parent_root = BTRFS_I(parent_inode)->root;
1603 ret = record_root_in_trans(trans, parent_root, 0);
1604 if (ret)
1605 goto fail;
1606 cur_time = current_time(parent_inode);
1607
1608 /*
1609 * insert the directory item
1610 */
1611 ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1612 BUG_ON(ret); /* -ENOMEM */
1613
1614 /* check if there is a file/dir which has the same name. */
1615 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1616 btrfs_ino(BTRFS_I(parent_inode)),
1617 dentry->d_name.name,
1618 dentry->d_name.len, 0);
1619 if (dir_item != NULL && !IS_ERR(dir_item)) {
1620 pending->error = -EEXIST;
1621 goto dir_item_existed;
1622 } else if (IS_ERR(dir_item)) {
1623 ret = PTR_ERR(dir_item);
1624 btrfs_abort_transaction(trans, ret);
1625 goto fail;
1626 }
1627 btrfs_release_path(path);
1628
1629 /*
1630 * pull in the delayed directory update
1631 * and the delayed inode item
1632 * otherwise we corrupt the FS during
1633 * snapshot
1634 */
1635 ret = btrfs_run_delayed_items(trans);
1636 if (ret) { /* Transaction aborted */
1637 btrfs_abort_transaction(trans, ret);
1638 goto fail;
1639 }
1640
1641 ret = record_root_in_trans(trans, root, 0);
1642 if (ret) {
1643 btrfs_abort_transaction(trans, ret);
1644 goto fail;
1645 }
1646 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1647 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1648 btrfs_check_and_init_root_item(new_root_item);
1649
1650 root_flags = btrfs_root_flags(new_root_item);
1651 if (pending->readonly)
1652 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1653 else
1654 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1655 btrfs_set_root_flags(new_root_item, root_flags);
1656
1657 btrfs_set_root_generation_v2(new_root_item,
1658 trans->transid);
1659 generate_random_guid(new_root_item->uuid);
1660 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1661 BTRFS_UUID_SIZE);
1662 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1663 memset(new_root_item->received_uuid, 0,
1664 sizeof(new_root_item->received_uuid));
1665 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1666 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1667 btrfs_set_root_stransid(new_root_item, 0);
1668 btrfs_set_root_rtransid(new_root_item, 0);
1669 }
1670 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1671 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1672 btrfs_set_root_otransid(new_root_item, trans->transid);
1673
1674 old = btrfs_lock_root_node(root);
1675 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1676 BTRFS_NESTING_COW);
1677 if (ret) {
1678 btrfs_tree_unlock(old);
1679 free_extent_buffer(old);
1680 btrfs_abort_transaction(trans, ret);
1681 goto fail;
1682 }
1683
1684 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1685 /* clean up in any case */
1686 btrfs_tree_unlock(old);
1687 free_extent_buffer(old);
1688 if (ret) {
1689 btrfs_abort_transaction(trans, ret);
1690 goto fail;
1691 }
1692 /* see comments in should_cow_block() */
1693 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1694 smp_wmb();
1695
1696 btrfs_set_root_node(new_root_item, tmp);
1697 /* record when the snapshot was created in key.offset */
1698 key.offset = trans->transid;
1699 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1700 btrfs_tree_unlock(tmp);
1701 free_extent_buffer(tmp);
1702 if (ret) {
1703 btrfs_abort_transaction(trans, ret);
1704 goto fail;
1705 }
1706
1707 /*
1708 * insert root back/forward references
1709 */
1710 ret = btrfs_add_root_ref(trans, objectid,
1711 parent_root->root_key.objectid,
1712 btrfs_ino(BTRFS_I(parent_inode)), index,
1713 dentry->d_name.name, dentry->d_name.len);
1714 if (ret) {
1715 btrfs_abort_transaction(trans, ret);
1716 goto fail;
1717 }
1718
1719 key.offset = (u64)-1;
1720 pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1721 if (IS_ERR(pending->snap)) {
1722 ret = PTR_ERR(pending->snap);
1723 pending->snap = NULL;
1724 btrfs_abort_transaction(trans, ret);
1725 goto fail;
1726 }
1727
1728 ret = btrfs_reloc_post_snapshot(trans, pending);
1729 if (ret) {
1730 btrfs_abort_transaction(trans, ret);
1731 goto fail;
1732 }
1733
1734 /*
1735 * Do special qgroup accounting for snapshot, as we do some qgroup
1736 * snapshot hack to do fast snapshot.
1737 * To co-operate with that hack, we do hack again.
1738 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1739 */
1740 ret = qgroup_account_snapshot(trans, root, parent_root,
1741 pending->inherit, objectid);
1742 if (ret < 0)
1743 goto fail;
1744
1745 ret = btrfs_insert_dir_item(trans, dentry->d_name.name,
1746 dentry->d_name.len, BTRFS_I(parent_inode),
1747 &key, BTRFS_FT_DIR, index);
1748 /* We have check then name at the beginning, so it is impossible. */
1749 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1750 if (ret) {
1751 btrfs_abort_transaction(trans, ret);
1752 goto fail;
1753 }
1754
1755 btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1756 dentry->d_name.len * 2);
1757 parent_inode->i_mtime = parent_inode->i_ctime =
1758 current_time(parent_inode);
1759 ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
1760 if (ret) {
1761 btrfs_abort_transaction(trans, ret);
1762 goto fail;
1763 }
1764 ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1765 BTRFS_UUID_KEY_SUBVOL,
1766 objectid);
1767 if (ret) {
1768 btrfs_abort_transaction(trans, ret);
1769 goto fail;
1770 }
1771 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1772 ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1773 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1774 objectid);
1775 if (ret && ret != -EEXIST) {
1776 btrfs_abort_transaction(trans, ret);
1777 goto fail;
1778 }
1779 }
1780
1781fail:
1782 pending->error = ret;
1783dir_item_existed:
1784 trans->block_rsv = rsv;
1785 trans->bytes_reserved = 0;
1786clear_skip_qgroup:
1787 btrfs_clear_skip_qgroup(trans);
1788no_free_objectid:
1789 kfree(new_root_item);
1790 pending->root_item = NULL;
1791 btrfs_free_path(path);
1792 pending->path = NULL;
1793
1794 return ret;
1795}
1796
1797/*
1798 * create all the snapshots we've scheduled for creation
1799 */
1800static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1801{
1802 struct btrfs_pending_snapshot *pending, *next;
1803 struct list_head *head = &trans->transaction->pending_snapshots;
1804 int ret = 0;
1805
1806 list_for_each_entry_safe(pending, next, head, list) {
1807 list_del(&pending->list);
1808 ret = create_pending_snapshot(trans, pending);
1809 if (ret)
1810 break;
1811 }
1812 return ret;
1813}
1814
1815static void update_super_roots(struct btrfs_fs_info *fs_info)
1816{
1817 struct btrfs_root_item *root_item;
1818 struct btrfs_super_block *super;
1819
1820 super = fs_info->super_copy;
1821
1822 root_item = &fs_info->chunk_root->root_item;
1823 super->chunk_root = root_item->bytenr;
1824 super->chunk_root_generation = root_item->generation;
1825 super->chunk_root_level = root_item->level;
1826
1827 root_item = &fs_info->tree_root->root_item;
1828 super->root = root_item->bytenr;
1829 super->generation = root_item->generation;
1830 super->root_level = root_item->level;
1831 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1832 super->cache_generation = root_item->generation;
1833 else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1834 super->cache_generation = 0;
1835 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1836 super->uuid_tree_generation = root_item->generation;
1837}
1838
1839int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1840{
1841 struct btrfs_transaction *trans;
1842 int ret = 0;
1843
1844 spin_lock(&info->trans_lock);
1845 trans = info->running_transaction;
1846 if (trans)
1847 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1848 spin_unlock(&info->trans_lock);
1849 return ret;
1850}
1851
1852int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1853{
1854 struct btrfs_transaction *trans;
1855 int ret = 0;
1856
1857 spin_lock(&info->trans_lock);
1858 trans = info->running_transaction;
1859 if (trans)
1860 ret = is_transaction_blocked(trans);
1861 spin_unlock(&info->trans_lock);
1862 return ret;
1863}
1864
1865/*
1866 * commit transactions asynchronously. once btrfs_commit_transaction_async
1867 * returns, any subsequent transaction will not be allowed to join.
1868 */
1869struct btrfs_async_commit {
1870 struct btrfs_trans_handle *newtrans;
1871 struct work_struct work;
1872};
1873
1874static void do_async_commit(struct work_struct *work)
1875{
1876 struct btrfs_async_commit *ac =
1877 container_of(work, struct btrfs_async_commit, work);
1878
1879 /*
1880 * We've got freeze protection passed with the transaction.
1881 * Tell lockdep about it.
1882 */
1883 if (ac->newtrans->type & __TRANS_FREEZABLE)
1884 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
1885
1886 current->journal_info = ac->newtrans;
1887
1888 btrfs_commit_transaction(ac->newtrans);
1889 kfree(ac);
1890}
1891
1892int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1893{
1894 struct btrfs_fs_info *fs_info = trans->fs_info;
1895 struct btrfs_async_commit *ac;
1896 struct btrfs_transaction *cur_trans;
1897
1898 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1899 if (!ac)
1900 return -ENOMEM;
1901
1902 INIT_WORK(&ac->work, do_async_commit);
1903 ac->newtrans = btrfs_join_transaction(trans->root);
1904 if (IS_ERR(ac->newtrans)) {
1905 int err = PTR_ERR(ac->newtrans);
1906 kfree(ac);
1907 return err;
1908 }
1909
1910 /* take transaction reference */
1911 cur_trans = trans->transaction;
1912 refcount_inc(&cur_trans->use_count);
1913
1914 btrfs_end_transaction(trans);
1915
1916 /*
1917 * Tell lockdep we've released the freeze rwsem, since the
1918 * async commit thread will be the one to unlock it.
1919 */
1920 if (ac->newtrans->type & __TRANS_FREEZABLE)
1921 __sb_writers_release(fs_info->sb, SB_FREEZE_FS);
1922
1923 schedule_work(&ac->work);
1924 /*
1925 * Wait for the current transaction commit to start and block
1926 * subsequent transaction joins
1927 */
1928 wait_event(fs_info->transaction_blocked_wait,
1929 cur_trans->state >= TRANS_STATE_COMMIT_START ||
1930 TRANS_ABORTED(cur_trans));
1931 if (current->journal_info == trans)
1932 current->journal_info = NULL;
1933
1934 btrfs_put_transaction(cur_trans);
1935 return 0;
1936}
1937
1938
1939static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1940{
1941 struct btrfs_fs_info *fs_info = trans->fs_info;
1942 struct btrfs_transaction *cur_trans = trans->transaction;
1943
1944 WARN_ON(refcount_read(&trans->use_count) > 1);
1945
1946 btrfs_abort_transaction(trans, err);
1947
1948 spin_lock(&fs_info->trans_lock);
1949
1950 /*
1951 * If the transaction is removed from the list, it means this
1952 * transaction has been committed successfully, so it is impossible
1953 * to call the cleanup function.
1954 */
1955 BUG_ON(list_empty(&cur_trans->list));
1956
1957 if (cur_trans == fs_info->running_transaction) {
1958 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1959 spin_unlock(&fs_info->trans_lock);
1960 wait_event(cur_trans->writer_wait,
1961 atomic_read(&cur_trans->num_writers) == 1);
1962
1963 spin_lock(&fs_info->trans_lock);
1964 }
1965
1966 /*
1967 * Now that we know no one else is still using the transaction we can
1968 * remove the transaction from the list of transactions. This avoids
1969 * the transaction kthread from cleaning up the transaction while some
1970 * other task is still using it, which could result in a use-after-free
1971 * on things like log trees, as it forces the transaction kthread to
1972 * wait for this transaction to be cleaned up by us.
1973 */
1974 list_del_init(&cur_trans->list);
1975
1976 spin_unlock(&fs_info->trans_lock);
1977
1978 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
1979
1980 spin_lock(&fs_info->trans_lock);
1981 if (cur_trans == fs_info->running_transaction)
1982 fs_info->running_transaction = NULL;
1983 spin_unlock(&fs_info->trans_lock);
1984
1985 if (trans->type & __TRANS_FREEZABLE)
1986 sb_end_intwrite(fs_info->sb);
1987 btrfs_put_transaction(cur_trans);
1988 btrfs_put_transaction(cur_trans);
1989
1990 trace_btrfs_transaction_commit(trans->root);
1991
1992 if (current->journal_info == trans)
1993 current->journal_info = NULL;
1994 btrfs_scrub_cancel(fs_info);
1995
1996 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1997}
1998
1999/*
2000 * Release reserved delayed ref space of all pending block groups of the
2001 * transaction and remove them from the list
2002 */
2003static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2004{
2005 struct btrfs_fs_info *fs_info = trans->fs_info;
2006 struct btrfs_block_group *block_group, *tmp;
2007
2008 list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2009 btrfs_delayed_refs_rsv_release(fs_info, 1);
2010 list_del_init(&block_group->bg_list);
2011 }
2012}
2013
2014static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2015{
2016 /*
2017 * We use writeback_inodes_sb here because if we used
2018 * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2019 * Currently are holding the fs freeze lock, if we do an async flush
2020 * we'll do btrfs_join_transaction() and deadlock because we need to
2021 * wait for the fs freeze lock. Using the direct flushing we benefit
2022 * from already being in a transaction and our join_transaction doesn't
2023 * have to re-take the fs freeze lock.
2024 */
2025 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2026 writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2027 return 0;
2028}
2029
2030static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2031{
2032 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2033 btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2034}
2035
2036int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2037{
2038 struct btrfs_fs_info *fs_info = trans->fs_info;
2039 struct btrfs_transaction *cur_trans = trans->transaction;
2040 struct btrfs_transaction *prev_trans = NULL;
2041 int ret;
2042
2043 ASSERT(refcount_read(&trans->use_count) == 1);
2044
2045 /* Stop the commit early if ->aborted is set */
2046 if (TRANS_ABORTED(cur_trans)) {
2047 ret = cur_trans->aborted;
2048 btrfs_end_transaction(trans);
2049 return ret;
2050 }
2051
2052 btrfs_trans_release_metadata(trans);
2053 trans->block_rsv = NULL;
2054
2055 /*
2056 * We only want one transaction commit doing the flushing so we do not
2057 * waste a bunch of time on lock contention on the extent root node.
2058 */
2059 if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2060 &cur_trans->delayed_refs.flags)) {
2061 /*
2062 * Make a pass through all the delayed refs we have so far.
2063 * Any running threads may add more while we are here.
2064 */
2065 ret = btrfs_run_delayed_refs(trans, 0);
2066 if (ret) {
2067 btrfs_end_transaction(trans);
2068 return ret;
2069 }
2070 }
2071
2072 btrfs_create_pending_block_groups(trans);
2073
2074 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2075 int run_it = 0;
2076
2077 /* this mutex is also taken before trying to set
2078 * block groups readonly. We need to make sure
2079 * that nobody has set a block group readonly
2080 * after a extents from that block group have been
2081 * allocated for cache files. btrfs_set_block_group_ro
2082 * will wait for the transaction to commit if it
2083 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2084 *
2085 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2086 * only one process starts all the block group IO. It wouldn't
2087 * hurt to have more than one go through, but there's no
2088 * real advantage to it either.
2089 */
2090 mutex_lock(&fs_info->ro_block_group_mutex);
2091 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2092 &cur_trans->flags))
2093 run_it = 1;
2094 mutex_unlock(&fs_info->ro_block_group_mutex);
2095
2096 if (run_it) {
2097 ret = btrfs_start_dirty_block_groups(trans);
2098 if (ret) {
2099 btrfs_end_transaction(trans);
2100 return ret;
2101 }
2102 }
2103 }
2104
2105 spin_lock(&fs_info->trans_lock);
2106 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2107 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2108
2109 spin_unlock(&fs_info->trans_lock);
2110 refcount_inc(&cur_trans->use_count);
2111
2112 if (trans->in_fsync)
2113 want_state = TRANS_STATE_SUPER_COMMITTED;
2114 ret = btrfs_end_transaction(trans);
2115 wait_for_commit(cur_trans, want_state);
2116
2117 if (TRANS_ABORTED(cur_trans))
2118 ret = cur_trans->aborted;
2119
2120 btrfs_put_transaction(cur_trans);
2121
2122 return ret;
2123 }
2124
2125 cur_trans->state = TRANS_STATE_COMMIT_START;
2126 wake_up(&fs_info->transaction_blocked_wait);
2127
2128 if (cur_trans->list.prev != &fs_info->trans_list) {
2129 enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2130
2131 if (trans->in_fsync)
2132 want_state = TRANS_STATE_SUPER_COMMITTED;
2133
2134 prev_trans = list_entry(cur_trans->list.prev,
2135 struct btrfs_transaction, list);
2136 if (prev_trans->state < want_state) {
2137 refcount_inc(&prev_trans->use_count);
2138 spin_unlock(&fs_info->trans_lock);
2139
2140 wait_for_commit(prev_trans, want_state);
2141
2142 ret = READ_ONCE(prev_trans->aborted);
2143
2144 btrfs_put_transaction(prev_trans);
2145 if (ret)
2146 goto cleanup_transaction;
2147 } else {
2148 spin_unlock(&fs_info->trans_lock);
2149 }
2150 } else {
2151 spin_unlock(&fs_info->trans_lock);
2152 /*
2153 * The previous transaction was aborted and was already removed
2154 * from the list of transactions at fs_info->trans_list. So we
2155 * abort to prevent writing a new superblock that reflects a
2156 * corrupt state (pointing to trees with unwritten nodes/leafs).
2157 */
2158 if (test_bit(BTRFS_FS_STATE_TRANS_ABORTED, &fs_info->fs_state)) {
2159 ret = -EROFS;
2160 goto cleanup_transaction;
2161 }
2162 }
2163
2164 extwriter_counter_dec(cur_trans, trans->type);
2165
2166 ret = btrfs_start_delalloc_flush(fs_info);
2167 if (ret)
2168 goto cleanup_transaction;
2169
2170 ret = btrfs_run_delayed_items(trans);
2171 if (ret)
2172 goto cleanup_transaction;
2173
2174 wait_event(cur_trans->writer_wait,
2175 extwriter_counter_read(cur_trans) == 0);
2176
2177 /* some pending stuffs might be added after the previous flush. */
2178 ret = btrfs_run_delayed_items(trans);
2179 if (ret)
2180 goto cleanup_transaction;
2181
2182 btrfs_wait_delalloc_flush(fs_info);
2183
2184 /*
2185 * Wait for all ordered extents started by a fast fsync that joined this
2186 * transaction. Otherwise if this transaction commits before the ordered
2187 * extents complete we lose logged data after a power failure.
2188 */
2189 wait_event(cur_trans->pending_wait,
2190 atomic_read(&cur_trans->pending_ordered) == 0);
2191
2192 btrfs_scrub_pause(fs_info);
2193 /*
2194 * Ok now we need to make sure to block out any other joins while we
2195 * commit the transaction. We could have started a join before setting
2196 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2197 */
2198 spin_lock(&fs_info->trans_lock);
2199 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2200 spin_unlock(&fs_info->trans_lock);
2201 wait_event(cur_trans->writer_wait,
2202 atomic_read(&cur_trans->num_writers) == 1);
2203
2204 if (TRANS_ABORTED(cur_trans)) {
2205 ret = cur_trans->aborted;
2206 goto scrub_continue;
2207 }
2208 /*
2209 * the reloc mutex makes sure that we stop
2210 * the balancing code from coming in and moving
2211 * extents around in the middle of the commit
2212 */
2213 mutex_lock(&fs_info->reloc_mutex);
2214
2215 /*
2216 * We needn't worry about the delayed items because we will
2217 * deal with them in create_pending_snapshot(), which is the
2218 * core function of the snapshot creation.
2219 */
2220 ret = create_pending_snapshots(trans);
2221 if (ret)
2222 goto unlock_reloc;
2223
2224 /*
2225 * We insert the dir indexes of the snapshots and update the inode
2226 * of the snapshots' parents after the snapshot creation, so there
2227 * are some delayed items which are not dealt with. Now deal with
2228 * them.
2229 *
2230 * We needn't worry that this operation will corrupt the snapshots,
2231 * because all the tree which are snapshoted will be forced to COW
2232 * the nodes and leaves.
2233 */
2234 ret = btrfs_run_delayed_items(trans);
2235 if (ret)
2236 goto unlock_reloc;
2237
2238 ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2239 if (ret)
2240 goto unlock_reloc;
2241
2242 /*
2243 * make sure none of the code above managed to slip in a
2244 * delayed item
2245 */
2246 btrfs_assert_delayed_root_empty(fs_info);
2247
2248 WARN_ON(cur_trans != trans->transaction);
2249
2250 /* btrfs_commit_tree_roots is responsible for getting the
2251 * various roots consistent with each other. Every pointer
2252 * in the tree of tree roots has to point to the most up to date
2253 * root for every subvolume and other tree. So, we have to keep
2254 * the tree logging code from jumping in and changing any
2255 * of the trees.
2256 *
2257 * At this point in the commit, there can't be any tree-log
2258 * writers, but a little lower down we drop the trans mutex
2259 * and let new people in. By holding the tree_log_mutex
2260 * from now until after the super is written, we avoid races
2261 * with the tree-log code.
2262 */
2263 mutex_lock(&fs_info->tree_log_mutex);
2264
2265 ret = commit_fs_roots(trans);
2266 if (ret)
2267 goto unlock_tree_log;
2268
2269 /*
2270 * Since the transaction is done, we can apply the pending changes
2271 * before the next transaction.
2272 */
2273 btrfs_apply_pending_changes(fs_info);
2274
2275 /* commit_fs_roots gets rid of all the tree log roots, it is now
2276 * safe to free the root of tree log roots
2277 */
2278 btrfs_free_log_root_tree(trans, fs_info);
2279
2280 /*
2281 * Since fs roots are all committed, we can get a quite accurate
2282 * new_roots. So let's do quota accounting.
2283 */
2284 ret = btrfs_qgroup_account_extents(trans);
2285 if (ret < 0)
2286 goto unlock_tree_log;
2287
2288 ret = commit_cowonly_roots(trans);
2289 if (ret)
2290 goto unlock_tree_log;
2291
2292 /*
2293 * The tasks which save the space cache and inode cache may also
2294 * update ->aborted, check it.
2295 */
2296 if (TRANS_ABORTED(cur_trans)) {
2297 ret = cur_trans->aborted;
2298 goto unlock_tree_log;
2299 }
2300
2301 cur_trans = fs_info->running_transaction;
2302
2303 btrfs_set_root_node(&fs_info->tree_root->root_item,
2304 fs_info->tree_root->node);
2305 list_add_tail(&fs_info->tree_root->dirty_list,
2306 &cur_trans->switch_commits);
2307
2308 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2309 fs_info->chunk_root->node);
2310 list_add_tail(&fs_info->chunk_root->dirty_list,
2311 &cur_trans->switch_commits);
2312
2313 switch_commit_roots(trans);
2314
2315 ASSERT(list_empty(&cur_trans->dirty_bgs));
2316 ASSERT(list_empty(&cur_trans->io_bgs));
2317 update_super_roots(fs_info);
2318
2319 btrfs_set_super_log_root(fs_info->super_copy, 0);
2320 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2321 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2322 sizeof(*fs_info->super_copy));
2323
2324 btrfs_commit_device_sizes(cur_trans);
2325
2326 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2327 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2328
2329 btrfs_trans_release_chunk_metadata(trans);
2330
2331 spin_lock(&fs_info->trans_lock);
2332 cur_trans->state = TRANS_STATE_UNBLOCKED;
2333 fs_info->running_transaction = NULL;
2334 spin_unlock(&fs_info->trans_lock);
2335 mutex_unlock(&fs_info->reloc_mutex);
2336
2337 wake_up(&fs_info->transaction_wait);
2338
2339 ret = btrfs_write_and_wait_transaction(trans);
2340 if (ret) {
2341 btrfs_handle_fs_error(fs_info, ret,
2342 "Error while writing out transaction");
2343 /*
2344 * reloc_mutex has been unlocked, tree_log_mutex is still held
2345 * but we can't jump to unlock_tree_log causing double unlock
2346 */
2347 mutex_unlock(&fs_info->tree_log_mutex);
2348 goto scrub_continue;
2349 }
2350
2351 /*
2352 * At this point, we should have written all the tree blocks allocated
2353 * in this transaction. So it's now safe to free the redirtyied extent
2354 * buffers.
2355 */
2356 btrfs_free_redirty_list(cur_trans);
2357
2358 ret = write_all_supers(fs_info, 0);
2359 /*
2360 * the super is written, we can safely allow the tree-loggers
2361 * to go about their business
2362 */
2363 mutex_unlock(&fs_info->tree_log_mutex);
2364 if (ret)
2365 goto scrub_continue;
2366
2367 /*
2368 * We needn't acquire the lock here because there is no other task
2369 * which can change it.
2370 */
2371 cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2372 wake_up(&cur_trans->commit_wait);
2373
2374 btrfs_finish_extent_commit(trans);
2375
2376 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2377 btrfs_clear_space_info_full(fs_info);
2378
2379 fs_info->last_trans_committed = cur_trans->transid;
2380 /*
2381 * We needn't acquire the lock here because there is no other task
2382 * which can change it.
2383 */
2384 cur_trans->state = TRANS_STATE_COMPLETED;
2385 wake_up(&cur_trans->commit_wait);
2386
2387 spin_lock(&fs_info->trans_lock);
2388 list_del_init(&cur_trans->list);
2389 spin_unlock(&fs_info->trans_lock);
2390
2391 btrfs_put_transaction(cur_trans);
2392 btrfs_put_transaction(cur_trans);
2393
2394 if (trans->type & __TRANS_FREEZABLE)
2395 sb_end_intwrite(fs_info->sb);
2396
2397 trace_btrfs_transaction_commit(trans->root);
2398
2399 btrfs_scrub_continue(fs_info);
2400
2401 if (current->journal_info == trans)
2402 current->journal_info = NULL;
2403
2404 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2405
2406 return ret;
2407
2408unlock_tree_log:
2409 mutex_unlock(&fs_info->tree_log_mutex);
2410unlock_reloc:
2411 mutex_unlock(&fs_info->reloc_mutex);
2412scrub_continue:
2413 btrfs_scrub_continue(fs_info);
2414cleanup_transaction:
2415 btrfs_trans_release_metadata(trans);
2416 btrfs_cleanup_pending_block_groups(trans);
2417 btrfs_trans_release_chunk_metadata(trans);
2418 trans->block_rsv = NULL;
2419 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2420 if (current->journal_info == trans)
2421 current->journal_info = NULL;
2422 cleanup_transaction(trans, ret);
2423
2424 return ret;
2425}
2426
2427/*
2428 * return < 0 if error
2429 * 0 if there are no more dead_roots at the time of call
2430 * 1 there are more to be processed, call me again
2431 *
2432 * The return value indicates there are certainly more snapshots to delete, but
2433 * if there comes a new one during processing, it may return 0. We don't mind,
2434 * because btrfs_commit_super will poke cleaner thread and it will process it a
2435 * few seconds later.
2436 */
2437int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2438{
2439 int ret;
2440 struct btrfs_fs_info *fs_info = root->fs_info;
2441
2442 spin_lock(&fs_info->trans_lock);
2443 if (list_empty(&fs_info->dead_roots)) {
2444 spin_unlock(&fs_info->trans_lock);
2445 return 0;
2446 }
2447 root = list_first_entry(&fs_info->dead_roots,
2448 struct btrfs_root, root_list);
2449 list_del_init(&root->root_list);
2450 spin_unlock(&fs_info->trans_lock);
2451
2452 btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2453
2454 btrfs_kill_all_delayed_nodes(root);
2455
2456 if (btrfs_header_backref_rev(root->node) <
2457 BTRFS_MIXED_BACKREF_REV)
2458 ret = btrfs_drop_snapshot(root, 0, 0);
2459 else
2460 ret = btrfs_drop_snapshot(root, 1, 0);
2461
2462 btrfs_put_root(root);
2463 return (ret < 0) ? 0 : 1;
2464}
2465
2466void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2467{
2468 unsigned long prev;
2469 unsigned long bit;
2470
2471 prev = xchg(&fs_info->pending_changes, 0);
2472 if (!prev)
2473 return;
2474
2475 bit = 1 << BTRFS_PENDING_COMMIT;
2476 if (prev & bit)
2477 btrfs_debug(fs_info, "pending commit done");
2478 prev &= ~bit;
2479
2480 if (prev)
2481 btrfs_warn(fs_info,
2482 "unknown pending changes left 0x%lx, ignoring", prev);
2483}
1/*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/fs.h>
20#include <linux/slab.h>
21#include <linux/sched.h>
22#include <linux/writeback.h>
23#include <linux/pagemap.h>
24#include <linux/blkdev.h>
25#include <linux/uuid.h>
26#include "ctree.h"
27#include "disk-io.h"
28#include "transaction.h"
29#include "locking.h"
30#include "tree-log.h"
31#include "inode-map.h"
32#include "volumes.h"
33#include "dev-replace.h"
34#include "qgroup.h"
35
36#define BTRFS_ROOT_TRANS_TAG 0
37
38static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
39 [TRANS_STATE_RUNNING] = 0U,
40 [TRANS_STATE_BLOCKED] = (__TRANS_USERSPACE |
41 __TRANS_START),
42 [TRANS_STATE_COMMIT_START] = (__TRANS_USERSPACE |
43 __TRANS_START |
44 __TRANS_ATTACH),
45 [TRANS_STATE_COMMIT_DOING] = (__TRANS_USERSPACE |
46 __TRANS_START |
47 __TRANS_ATTACH |
48 __TRANS_JOIN),
49 [TRANS_STATE_UNBLOCKED] = (__TRANS_USERSPACE |
50 __TRANS_START |
51 __TRANS_ATTACH |
52 __TRANS_JOIN |
53 __TRANS_JOIN_NOLOCK),
54 [TRANS_STATE_COMPLETED] = (__TRANS_USERSPACE |
55 __TRANS_START |
56 __TRANS_ATTACH |
57 __TRANS_JOIN |
58 __TRANS_JOIN_NOLOCK),
59};
60
61void btrfs_put_transaction(struct btrfs_transaction *transaction)
62{
63 WARN_ON(atomic_read(&transaction->use_count) == 0);
64 if (atomic_dec_and_test(&transaction->use_count)) {
65 BUG_ON(!list_empty(&transaction->list));
66 WARN_ON(!RB_EMPTY_ROOT(&transaction->delayed_refs.href_root));
67 if (transaction->delayed_refs.pending_csums)
68 btrfs_err(transaction->fs_info,
69 "pending csums is %llu",
70 transaction->delayed_refs.pending_csums);
71 while (!list_empty(&transaction->pending_chunks)) {
72 struct extent_map *em;
73
74 em = list_first_entry(&transaction->pending_chunks,
75 struct extent_map, list);
76 list_del_init(&em->list);
77 free_extent_map(em);
78 }
79 /*
80 * If any block groups are found in ->deleted_bgs then it's
81 * because the transaction was aborted and a commit did not
82 * happen (things failed before writing the new superblock
83 * and calling btrfs_finish_extent_commit()), so we can not
84 * discard the physical locations of the block groups.
85 */
86 while (!list_empty(&transaction->deleted_bgs)) {
87 struct btrfs_block_group_cache *cache;
88
89 cache = list_first_entry(&transaction->deleted_bgs,
90 struct btrfs_block_group_cache,
91 bg_list);
92 list_del_init(&cache->bg_list);
93 btrfs_put_block_group_trimming(cache);
94 btrfs_put_block_group(cache);
95 }
96 kmem_cache_free(btrfs_transaction_cachep, transaction);
97 }
98}
99
100static void clear_btree_io_tree(struct extent_io_tree *tree)
101{
102 spin_lock(&tree->lock);
103 /*
104 * Do a single barrier for the waitqueue_active check here, the state
105 * of the waitqueue should not change once clear_btree_io_tree is
106 * called.
107 */
108 smp_mb();
109 while (!RB_EMPTY_ROOT(&tree->state)) {
110 struct rb_node *node;
111 struct extent_state *state;
112
113 node = rb_first(&tree->state);
114 state = rb_entry(node, struct extent_state, rb_node);
115 rb_erase(&state->rb_node, &tree->state);
116 RB_CLEAR_NODE(&state->rb_node);
117 /*
118 * btree io trees aren't supposed to have tasks waiting for
119 * changes in the flags of extent states ever.
120 */
121 ASSERT(!waitqueue_active(&state->wq));
122 free_extent_state(state);
123
124 cond_resched_lock(&tree->lock);
125 }
126 spin_unlock(&tree->lock);
127}
128
129static noinline void switch_commit_roots(struct btrfs_transaction *trans,
130 struct btrfs_fs_info *fs_info)
131{
132 struct btrfs_root *root, *tmp;
133
134 down_write(&fs_info->commit_root_sem);
135 list_for_each_entry_safe(root, tmp, &trans->switch_commits,
136 dirty_list) {
137 list_del_init(&root->dirty_list);
138 free_extent_buffer(root->commit_root);
139 root->commit_root = btrfs_root_node(root);
140 if (is_fstree(root->objectid))
141 btrfs_unpin_free_ino(root);
142 clear_btree_io_tree(&root->dirty_log_pages);
143 }
144
145 /* We can free old roots now. */
146 spin_lock(&trans->dropped_roots_lock);
147 while (!list_empty(&trans->dropped_roots)) {
148 root = list_first_entry(&trans->dropped_roots,
149 struct btrfs_root, root_list);
150 list_del_init(&root->root_list);
151 spin_unlock(&trans->dropped_roots_lock);
152 btrfs_drop_and_free_fs_root(fs_info, root);
153 spin_lock(&trans->dropped_roots_lock);
154 }
155 spin_unlock(&trans->dropped_roots_lock);
156 up_write(&fs_info->commit_root_sem);
157}
158
159static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
160 unsigned int type)
161{
162 if (type & TRANS_EXTWRITERS)
163 atomic_inc(&trans->num_extwriters);
164}
165
166static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
167 unsigned int type)
168{
169 if (type & TRANS_EXTWRITERS)
170 atomic_dec(&trans->num_extwriters);
171}
172
173static inline void extwriter_counter_init(struct btrfs_transaction *trans,
174 unsigned int type)
175{
176 atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
177}
178
179static inline int extwriter_counter_read(struct btrfs_transaction *trans)
180{
181 return atomic_read(&trans->num_extwriters);
182}
183
184/*
185 * either allocate a new transaction or hop into the existing one
186 */
187static noinline int join_transaction(struct btrfs_fs_info *fs_info,
188 unsigned int type)
189{
190 struct btrfs_transaction *cur_trans;
191
192 spin_lock(&fs_info->trans_lock);
193loop:
194 /* The file system has been taken offline. No new transactions. */
195 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
196 spin_unlock(&fs_info->trans_lock);
197 return -EROFS;
198 }
199
200 cur_trans = fs_info->running_transaction;
201 if (cur_trans) {
202 if (cur_trans->aborted) {
203 spin_unlock(&fs_info->trans_lock);
204 return cur_trans->aborted;
205 }
206 if (btrfs_blocked_trans_types[cur_trans->state] & type) {
207 spin_unlock(&fs_info->trans_lock);
208 return -EBUSY;
209 }
210 atomic_inc(&cur_trans->use_count);
211 atomic_inc(&cur_trans->num_writers);
212 extwriter_counter_inc(cur_trans, type);
213 spin_unlock(&fs_info->trans_lock);
214 return 0;
215 }
216 spin_unlock(&fs_info->trans_lock);
217
218 /*
219 * If we are ATTACH, we just want to catch the current transaction,
220 * and commit it. If there is no transaction, just return ENOENT.
221 */
222 if (type == TRANS_ATTACH)
223 return -ENOENT;
224
225 /*
226 * JOIN_NOLOCK only happens during the transaction commit, so
227 * it is impossible that ->running_transaction is NULL
228 */
229 BUG_ON(type == TRANS_JOIN_NOLOCK);
230
231 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
232 if (!cur_trans)
233 return -ENOMEM;
234
235 spin_lock(&fs_info->trans_lock);
236 if (fs_info->running_transaction) {
237 /*
238 * someone started a transaction after we unlocked. Make sure
239 * to redo the checks above
240 */
241 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
242 goto loop;
243 } else if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state)) {
244 spin_unlock(&fs_info->trans_lock);
245 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
246 return -EROFS;
247 }
248
249 cur_trans->fs_info = fs_info;
250 atomic_set(&cur_trans->num_writers, 1);
251 extwriter_counter_init(cur_trans, type);
252 init_waitqueue_head(&cur_trans->writer_wait);
253 init_waitqueue_head(&cur_trans->commit_wait);
254 init_waitqueue_head(&cur_trans->pending_wait);
255 cur_trans->state = TRANS_STATE_RUNNING;
256 /*
257 * One for this trans handle, one so it will live on until we
258 * commit the transaction.
259 */
260 atomic_set(&cur_trans->use_count, 2);
261 atomic_set(&cur_trans->pending_ordered, 0);
262 cur_trans->flags = 0;
263 cur_trans->start_time = get_seconds();
264
265 memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
266
267 cur_trans->delayed_refs.href_root = RB_ROOT;
268 cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
269 atomic_set(&cur_trans->delayed_refs.num_entries, 0);
270
271 /*
272 * although the tree mod log is per file system and not per transaction,
273 * the log must never go across transaction boundaries.
274 */
275 smp_mb();
276 if (!list_empty(&fs_info->tree_mod_seq_list))
277 WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
278 if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
279 WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
280 atomic64_set(&fs_info->tree_mod_seq, 0);
281
282 spin_lock_init(&cur_trans->delayed_refs.lock);
283
284 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
285 INIT_LIST_HEAD(&cur_trans->pending_chunks);
286 INIT_LIST_HEAD(&cur_trans->switch_commits);
287 INIT_LIST_HEAD(&cur_trans->dirty_bgs);
288 INIT_LIST_HEAD(&cur_trans->io_bgs);
289 INIT_LIST_HEAD(&cur_trans->dropped_roots);
290 mutex_init(&cur_trans->cache_write_mutex);
291 cur_trans->num_dirty_bgs = 0;
292 spin_lock_init(&cur_trans->dirty_bgs_lock);
293 INIT_LIST_HEAD(&cur_trans->deleted_bgs);
294 spin_lock_init(&cur_trans->dropped_roots_lock);
295 list_add_tail(&cur_trans->list, &fs_info->trans_list);
296 extent_io_tree_init(&cur_trans->dirty_pages,
297 fs_info->btree_inode->i_mapping);
298 fs_info->generation++;
299 cur_trans->transid = fs_info->generation;
300 fs_info->running_transaction = cur_trans;
301 cur_trans->aborted = 0;
302 spin_unlock(&fs_info->trans_lock);
303
304 return 0;
305}
306
307/*
308 * this does all the record keeping required to make sure that a reference
309 * counted root is properly recorded in a given transaction. This is required
310 * to make sure the old root from before we joined the transaction is deleted
311 * when the transaction commits
312 */
313static int record_root_in_trans(struct btrfs_trans_handle *trans,
314 struct btrfs_root *root,
315 int force)
316{
317 struct btrfs_fs_info *fs_info = root->fs_info;
318
319 if ((test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
320 root->last_trans < trans->transid) || force) {
321 WARN_ON(root == fs_info->extent_root);
322 WARN_ON(root->commit_root != root->node);
323
324 /*
325 * see below for IN_TRANS_SETUP usage rules
326 * we have the reloc mutex held now, so there
327 * is only one writer in this function
328 */
329 set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
330
331 /* make sure readers find IN_TRANS_SETUP before
332 * they find our root->last_trans update
333 */
334 smp_wmb();
335
336 spin_lock(&fs_info->fs_roots_radix_lock);
337 if (root->last_trans == trans->transid && !force) {
338 spin_unlock(&fs_info->fs_roots_radix_lock);
339 return 0;
340 }
341 radix_tree_tag_set(&fs_info->fs_roots_radix,
342 (unsigned long)root->root_key.objectid,
343 BTRFS_ROOT_TRANS_TAG);
344 spin_unlock(&fs_info->fs_roots_radix_lock);
345 root->last_trans = trans->transid;
346
347 /* this is pretty tricky. We don't want to
348 * take the relocation lock in btrfs_record_root_in_trans
349 * unless we're really doing the first setup for this root in
350 * this transaction.
351 *
352 * Normally we'd use root->last_trans as a flag to decide
353 * if we want to take the expensive mutex.
354 *
355 * But, we have to set root->last_trans before we
356 * init the relocation root, otherwise, we trip over warnings
357 * in ctree.c. The solution used here is to flag ourselves
358 * with root IN_TRANS_SETUP. When this is 1, we're still
359 * fixing up the reloc trees and everyone must wait.
360 *
361 * When this is zero, they can trust root->last_trans and fly
362 * through btrfs_record_root_in_trans without having to take the
363 * lock. smp_wmb() makes sure that all the writes above are
364 * done before we pop in the zero below
365 */
366 btrfs_init_reloc_root(trans, root);
367 smp_mb__before_atomic();
368 clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
369 }
370 return 0;
371}
372
373
374void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
375 struct btrfs_root *root)
376{
377 struct btrfs_fs_info *fs_info = root->fs_info;
378 struct btrfs_transaction *cur_trans = trans->transaction;
379
380 /* Add ourselves to the transaction dropped list */
381 spin_lock(&cur_trans->dropped_roots_lock);
382 list_add_tail(&root->root_list, &cur_trans->dropped_roots);
383 spin_unlock(&cur_trans->dropped_roots_lock);
384
385 /* Make sure we don't try to update the root at commit time */
386 spin_lock(&fs_info->fs_roots_radix_lock);
387 radix_tree_tag_clear(&fs_info->fs_roots_radix,
388 (unsigned long)root->root_key.objectid,
389 BTRFS_ROOT_TRANS_TAG);
390 spin_unlock(&fs_info->fs_roots_radix_lock);
391}
392
393int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
394 struct btrfs_root *root)
395{
396 struct btrfs_fs_info *fs_info = root->fs_info;
397
398 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
399 return 0;
400
401 /*
402 * see record_root_in_trans for comments about IN_TRANS_SETUP usage
403 * and barriers
404 */
405 smp_rmb();
406 if (root->last_trans == trans->transid &&
407 !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
408 return 0;
409
410 mutex_lock(&fs_info->reloc_mutex);
411 record_root_in_trans(trans, root, 0);
412 mutex_unlock(&fs_info->reloc_mutex);
413
414 return 0;
415}
416
417static inline int is_transaction_blocked(struct btrfs_transaction *trans)
418{
419 return (trans->state >= TRANS_STATE_BLOCKED &&
420 trans->state < TRANS_STATE_UNBLOCKED &&
421 !trans->aborted);
422}
423
424/* wait for commit against the current transaction to become unblocked
425 * when this is done, it is safe to start a new transaction, but the current
426 * transaction might not be fully on disk.
427 */
428static void wait_current_trans(struct btrfs_fs_info *fs_info)
429{
430 struct btrfs_transaction *cur_trans;
431
432 spin_lock(&fs_info->trans_lock);
433 cur_trans = fs_info->running_transaction;
434 if (cur_trans && is_transaction_blocked(cur_trans)) {
435 atomic_inc(&cur_trans->use_count);
436 spin_unlock(&fs_info->trans_lock);
437
438 wait_event(fs_info->transaction_wait,
439 cur_trans->state >= TRANS_STATE_UNBLOCKED ||
440 cur_trans->aborted);
441 btrfs_put_transaction(cur_trans);
442 } else {
443 spin_unlock(&fs_info->trans_lock);
444 }
445}
446
447static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
448{
449 if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
450 return 0;
451
452 if (type == TRANS_USERSPACE)
453 return 1;
454
455 if (type == TRANS_START &&
456 !atomic_read(&fs_info->open_ioctl_trans))
457 return 1;
458
459 return 0;
460}
461
462static inline bool need_reserve_reloc_root(struct btrfs_root *root)
463{
464 struct btrfs_fs_info *fs_info = root->fs_info;
465
466 if (!fs_info->reloc_ctl ||
467 !test_bit(BTRFS_ROOT_REF_COWS, &root->state) ||
468 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
469 root->reloc_root)
470 return false;
471
472 return true;
473}
474
475static struct btrfs_trans_handle *
476start_transaction(struct btrfs_root *root, unsigned int num_items,
477 unsigned int type, enum btrfs_reserve_flush_enum flush)
478{
479 struct btrfs_fs_info *fs_info = root->fs_info;
480
481 struct btrfs_trans_handle *h;
482 struct btrfs_transaction *cur_trans;
483 u64 num_bytes = 0;
484 u64 qgroup_reserved = 0;
485 bool reloc_reserved = false;
486 int ret;
487
488 /* Send isn't supposed to start transactions. */
489 ASSERT(current->journal_info != BTRFS_SEND_TRANS_STUB);
490
491 if (test_bit(BTRFS_FS_STATE_ERROR, &fs_info->fs_state))
492 return ERR_PTR(-EROFS);
493
494 if (current->journal_info) {
495 WARN_ON(type & TRANS_EXTWRITERS);
496 h = current->journal_info;
497 h->use_count++;
498 WARN_ON(h->use_count > 2);
499 h->orig_rsv = h->block_rsv;
500 h->block_rsv = NULL;
501 goto got_it;
502 }
503
504 /*
505 * Do the reservation before we join the transaction so we can do all
506 * the appropriate flushing if need be.
507 */
508 if (num_items > 0 && root != fs_info->chunk_root) {
509 qgroup_reserved = num_items * fs_info->nodesize;
510 ret = btrfs_qgroup_reserve_meta(root, qgroup_reserved);
511 if (ret)
512 return ERR_PTR(ret);
513
514 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
515 /*
516 * Do the reservation for the relocation root creation
517 */
518 if (need_reserve_reloc_root(root)) {
519 num_bytes += fs_info->nodesize;
520 reloc_reserved = true;
521 }
522
523 ret = btrfs_block_rsv_add(root, &fs_info->trans_block_rsv,
524 num_bytes, flush);
525 if (ret)
526 goto reserve_fail;
527 }
528again:
529 h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
530 if (!h) {
531 ret = -ENOMEM;
532 goto alloc_fail;
533 }
534
535 /*
536 * If we are JOIN_NOLOCK we're already committing a transaction and
537 * waiting on this guy, so we don't need to do the sb_start_intwrite
538 * because we're already holding a ref. We need this because we could
539 * have raced in and did an fsync() on a file which can kick a commit
540 * and then we deadlock with somebody doing a freeze.
541 *
542 * If we are ATTACH, it means we just want to catch the current
543 * transaction and commit it, so we needn't do sb_start_intwrite().
544 */
545 if (type & __TRANS_FREEZABLE)
546 sb_start_intwrite(fs_info->sb);
547
548 if (may_wait_transaction(fs_info, type))
549 wait_current_trans(fs_info);
550
551 do {
552 ret = join_transaction(fs_info, type);
553 if (ret == -EBUSY) {
554 wait_current_trans(fs_info);
555 if (unlikely(type == TRANS_ATTACH))
556 ret = -ENOENT;
557 }
558 } while (ret == -EBUSY);
559
560 if (ret < 0)
561 goto join_fail;
562
563 cur_trans = fs_info->running_transaction;
564
565 h->transid = cur_trans->transid;
566 h->transaction = cur_trans;
567 h->root = root;
568 h->use_count = 1;
569 h->fs_info = root->fs_info;
570
571 h->type = type;
572 h->can_flush_pending_bgs = true;
573 INIT_LIST_HEAD(&h->qgroup_ref_list);
574 INIT_LIST_HEAD(&h->new_bgs);
575
576 smp_mb();
577 if (cur_trans->state >= TRANS_STATE_BLOCKED &&
578 may_wait_transaction(fs_info, type)) {
579 current->journal_info = h;
580 btrfs_commit_transaction(h);
581 goto again;
582 }
583
584 if (num_bytes) {
585 trace_btrfs_space_reservation(fs_info, "transaction",
586 h->transid, num_bytes, 1);
587 h->block_rsv = &fs_info->trans_block_rsv;
588 h->bytes_reserved = num_bytes;
589 h->reloc_reserved = reloc_reserved;
590 }
591
592got_it:
593 btrfs_record_root_in_trans(h, root);
594
595 if (!current->journal_info && type != TRANS_USERSPACE)
596 current->journal_info = h;
597 return h;
598
599join_fail:
600 if (type & __TRANS_FREEZABLE)
601 sb_end_intwrite(fs_info->sb);
602 kmem_cache_free(btrfs_trans_handle_cachep, h);
603alloc_fail:
604 if (num_bytes)
605 btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
606 num_bytes);
607reserve_fail:
608 btrfs_qgroup_free_meta(root, qgroup_reserved);
609 return ERR_PTR(ret);
610}
611
612struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
613 unsigned int num_items)
614{
615 return start_transaction(root, num_items, TRANS_START,
616 BTRFS_RESERVE_FLUSH_ALL);
617}
618struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
619 struct btrfs_root *root,
620 unsigned int num_items,
621 int min_factor)
622{
623 struct btrfs_fs_info *fs_info = root->fs_info;
624 struct btrfs_trans_handle *trans;
625 u64 num_bytes;
626 int ret;
627
628 trans = btrfs_start_transaction(root, num_items);
629 if (!IS_ERR(trans) || PTR_ERR(trans) != -ENOSPC)
630 return trans;
631
632 trans = btrfs_start_transaction(root, 0);
633 if (IS_ERR(trans))
634 return trans;
635
636 num_bytes = btrfs_calc_trans_metadata_size(fs_info, num_items);
637 ret = btrfs_cond_migrate_bytes(fs_info, &fs_info->trans_block_rsv,
638 num_bytes, min_factor);
639 if (ret) {
640 btrfs_end_transaction(trans);
641 return ERR_PTR(ret);
642 }
643
644 trans->block_rsv = &fs_info->trans_block_rsv;
645 trans->bytes_reserved = num_bytes;
646 trace_btrfs_space_reservation(fs_info, "transaction",
647 trans->transid, num_bytes, 1);
648
649 return trans;
650}
651
652struct btrfs_trans_handle *btrfs_start_transaction_lflush(
653 struct btrfs_root *root,
654 unsigned int num_items)
655{
656 return start_transaction(root, num_items, TRANS_START,
657 BTRFS_RESERVE_FLUSH_LIMIT);
658}
659
660struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
661{
662 return start_transaction(root, 0, TRANS_JOIN,
663 BTRFS_RESERVE_NO_FLUSH);
664}
665
666struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
667{
668 return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
669 BTRFS_RESERVE_NO_FLUSH);
670}
671
672struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
673{
674 return start_transaction(root, 0, TRANS_USERSPACE,
675 BTRFS_RESERVE_NO_FLUSH);
676}
677
678/*
679 * btrfs_attach_transaction() - catch the running transaction
680 *
681 * It is used when we want to commit the current the transaction, but
682 * don't want to start a new one.
683 *
684 * Note: If this function return -ENOENT, it just means there is no
685 * running transaction. But it is possible that the inactive transaction
686 * is still in the memory, not fully on disk. If you hope there is no
687 * inactive transaction in the fs when -ENOENT is returned, you should
688 * invoke
689 * btrfs_attach_transaction_barrier()
690 */
691struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
692{
693 return start_transaction(root, 0, TRANS_ATTACH,
694 BTRFS_RESERVE_NO_FLUSH);
695}
696
697/*
698 * btrfs_attach_transaction_barrier() - catch the running transaction
699 *
700 * It is similar to the above function, the differentia is this one
701 * will wait for all the inactive transactions until they fully
702 * complete.
703 */
704struct btrfs_trans_handle *
705btrfs_attach_transaction_barrier(struct btrfs_root *root)
706{
707 struct btrfs_trans_handle *trans;
708
709 trans = start_transaction(root, 0, TRANS_ATTACH,
710 BTRFS_RESERVE_NO_FLUSH);
711 if (IS_ERR(trans) && PTR_ERR(trans) == -ENOENT)
712 btrfs_wait_for_commit(root->fs_info, 0);
713
714 return trans;
715}
716
717/* wait for a transaction commit to be fully complete */
718static noinline void wait_for_commit(struct btrfs_transaction *commit)
719{
720 wait_event(commit->commit_wait, commit->state == TRANS_STATE_COMPLETED);
721}
722
723int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
724{
725 struct btrfs_transaction *cur_trans = NULL, *t;
726 int ret = 0;
727
728 if (transid) {
729 if (transid <= fs_info->last_trans_committed)
730 goto out;
731
732 /* find specified transaction */
733 spin_lock(&fs_info->trans_lock);
734 list_for_each_entry(t, &fs_info->trans_list, list) {
735 if (t->transid == transid) {
736 cur_trans = t;
737 atomic_inc(&cur_trans->use_count);
738 ret = 0;
739 break;
740 }
741 if (t->transid > transid) {
742 ret = 0;
743 break;
744 }
745 }
746 spin_unlock(&fs_info->trans_lock);
747
748 /*
749 * The specified transaction doesn't exist, or we
750 * raced with btrfs_commit_transaction
751 */
752 if (!cur_trans) {
753 if (transid > fs_info->last_trans_committed)
754 ret = -EINVAL;
755 goto out;
756 }
757 } else {
758 /* find newest transaction that is committing | committed */
759 spin_lock(&fs_info->trans_lock);
760 list_for_each_entry_reverse(t, &fs_info->trans_list,
761 list) {
762 if (t->state >= TRANS_STATE_COMMIT_START) {
763 if (t->state == TRANS_STATE_COMPLETED)
764 break;
765 cur_trans = t;
766 atomic_inc(&cur_trans->use_count);
767 break;
768 }
769 }
770 spin_unlock(&fs_info->trans_lock);
771 if (!cur_trans)
772 goto out; /* nothing committing|committed */
773 }
774
775 wait_for_commit(cur_trans);
776 btrfs_put_transaction(cur_trans);
777out:
778 return ret;
779}
780
781void btrfs_throttle(struct btrfs_fs_info *fs_info)
782{
783 if (!atomic_read(&fs_info->open_ioctl_trans))
784 wait_current_trans(fs_info);
785}
786
787static int should_end_transaction(struct btrfs_trans_handle *trans)
788{
789 struct btrfs_fs_info *fs_info = trans->fs_info;
790
791 if (fs_info->global_block_rsv.space_info->full &&
792 btrfs_check_space_for_delayed_refs(trans, fs_info))
793 return 1;
794
795 return !!btrfs_block_rsv_check(&fs_info->global_block_rsv, 5);
796}
797
798int btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
799{
800 struct btrfs_transaction *cur_trans = trans->transaction;
801 struct btrfs_fs_info *fs_info = trans->fs_info;
802 int updates;
803 int err;
804
805 smp_mb();
806 if (cur_trans->state >= TRANS_STATE_BLOCKED ||
807 cur_trans->delayed_refs.flushing)
808 return 1;
809
810 updates = trans->delayed_ref_updates;
811 trans->delayed_ref_updates = 0;
812 if (updates) {
813 err = btrfs_run_delayed_refs(trans, fs_info, updates * 2);
814 if (err) /* Error code will also eval true */
815 return err;
816 }
817
818 return should_end_transaction(trans);
819}
820
821static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
822 int throttle)
823{
824 struct btrfs_fs_info *info = trans->fs_info;
825 struct btrfs_transaction *cur_trans = trans->transaction;
826 u64 transid = trans->transid;
827 unsigned long cur = trans->delayed_ref_updates;
828 int lock = (trans->type != TRANS_JOIN_NOLOCK);
829 int err = 0;
830 int must_run_delayed_refs = 0;
831
832 if (trans->use_count > 1) {
833 trans->use_count--;
834 trans->block_rsv = trans->orig_rsv;
835 return 0;
836 }
837
838 btrfs_trans_release_metadata(trans, info);
839 trans->block_rsv = NULL;
840
841 if (!list_empty(&trans->new_bgs))
842 btrfs_create_pending_block_groups(trans, info);
843
844 trans->delayed_ref_updates = 0;
845 if (!trans->sync) {
846 must_run_delayed_refs =
847 btrfs_should_throttle_delayed_refs(trans, info);
848 cur = max_t(unsigned long, cur, 32);
849
850 /*
851 * don't make the caller wait if they are from a NOLOCK
852 * or ATTACH transaction, it will deadlock with commit
853 */
854 if (must_run_delayed_refs == 1 &&
855 (trans->type & (__TRANS_JOIN_NOLOCK | __TRANS_ATTACH)))
856 must_run_delayed_refs = 2;
857 }
858
859 btrfs_trans_release_metadata(trans, info);
860 trans->block_rsv = NULL;
861
862 if (!list_empty(&trans->new_bgs))
863 btrfs_create_pending_block_groups(trans, info);
864
865 btrfs_trans_release_chunk_metadata(trans);
866
867 if (lock && !atomic_read(&info->open_ioctl_trans) &&
868 should_end_transaction(trans) &&
869 ACCESS_ONCE(cur_trans->state) == TRANS_STATE_RUNNING) {
870 spin_lock(&info->trans_lock);
871 if (cur_trans->state == TRANS_STATE_RUNNING)
872 cur_trans->state = TRANS_STATE_BLOCKED;
873 spin_unlock(&info->trans_lock);
874 }
875
876 if (lock && ACCESS_ONCE(cur_trans->state) == TRANS_STATE_BLOCKED) {
877 if (throttle)
878 return btrfs_commit_transaction(trans);
879 else
880 wake_up_process(info->transaction_kthread);
881 }
882
883 if (trans->type & __TRANS_FREEZABLE)
884 sb_end_intwrite(info->sb);
885
886 WARN_ON(cur_trans != info->running_transaction);
887 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
888 atomic_dec(&cur_trans->num_writers);
889 extwriter_counter_dec(cur_trans, trans->type);
890
891 /*
892 * Make sure counter is updated before we wake up waiters.
893 */
894 smp_mb();
895 if (waitqueue_active(&cur_trans->writer_wait))
896 wake_up(&cur_trans->writer_wait);
897 btrfs_put_transaction(cur_trans);
898
899 if (current->journal_info == trans)
900 current->journal_info = NULL;
901
902 if (throttle)
903 btrfs_run_delayed_iputs(info);
904
905 if (trans->aborted ||
906 test_bit(BTRFS_FS_STATE_ERROR, &info->fs_state)) {
907 wake_up_process(info->transaction_kthread);
908 err = -EIO;
909 }
910 assert_qgroups_uptodate(trans);
911
912 kmem_cache_free(btrfs_trans_handle_cachep, trans);
913 if (must_run_delayed_refs) {
914 btrfs_async_run_delayed_refs(info, cur, transid,
915 must_run_delayed_refs == 1);
916 }
917 return err;
918}
919
920int btrfs_end_transaction(struct btrfs_trans_handle *trans)
921{
922 return __btrfs_end_transaction(trans, 0);
923}
924
925int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
926{
927 return __btrfs_end_transaction(trans, 1);
928}
929
930/*
931 * when btree blocks are allocated, they have some corresponding bits set for
932 * them in one of two extent_io trees. This is used to make sure all of
933 * those extents are sent to disk but does not wait on them
934 */
935int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
936 struct extent_io_tree *dirty_pages, int mark)
937{
938 int err = 0;
939 int werr = 0;
940 struct address_space *mapping = fs_info->btree_inode->i_mapping;
941 struct extent_state *cached_state = NULL;
942 u64 start = 0;
943 u64 end;
944
945 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
946 mark, &cached_state)) {
947 bool wait_writeback = false;
948
949 err = convert_extent_bit(dirty_pages, start, end,
950 EXTENT_NEED_WAIT,
951 mark, &cached_state);
952 /*
953 * convert_extent_bit can return -ENOMEM, which is most of the
954 * time a temporary error. So when it happens, ignore the error
955 * and wait for writeback of this range to finish - because we
956 * failed to set the bit EXTENT_NEED_WAIT for the range, a call
957 * to __btrfs_wait_marked_extents() would not know that
958 * writeback for this range started and therefore wouldn't
959 * wait for it to finish - we don't want to commit a
960 * superblock that points to btree nodes/leafs for which
961 * writeback hasn't finished yet (and without errors).
962 * We cleanup any entries left in the io tree when committing
963 * the transaction (through clear_btree_io_tree()).
964 */
965 if (err == -ENOMEM) {
966 err = 0;
967 wait_writeback = true;
968 }
969 if (!err)
970 err = filemap_fdatawrite_range(mapping, start, end);
971 if (err)
972 werr = err;
973 else if (wait_writeback)
974 werr = filemap_fdatawait_range(mapping, start, end);
975 free_extent_state(cached_state);
976 cached_state = NULL;
977 cond_resched();
978 start = end + 1;
979 }
980 return werr;
981}
982
983/*
984 * when btree blocks are allocated, they have some corresponding bits set for
985 * them in one of two extent_io trees. This is used to make sure all of
986 * those extents are on disk for transaction or log commit. We wait
987 * on all the pages and clear them from the dirty pages state tree
988 */
989static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
990 struct extent_io_tree *dirty_pages)
991{
992 int err = 0;
993 int werr = 0;
994 struct address_space *mapping = fs_info->btree_inode->i_mapping;
995 struct extent_state *cached_state = NULL;
996 u64 start = 0;
997 u64 end;
998
999 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1000 EXTENT_NEED_WAIT, &cached_state)) {
1001 /*
1002 * Ignore -ENOMEM errors returned by clear_extent_bit().
1003 * When committing the transaction, we'll remove any entries
1004 * left in the io tree. For a log commit, we don't remove them
1005 * after committing the log because the tree can be accessed
1006 * concurrently - we do it only at transaction commit time when
1007 * it's safe to do it (through clear_btree_io_tree()).
1008 */
1009 err = clear_extent_bit(dirty_pages, start, end,
1010 EXTENT_NEED_WAIT,
1011 0, 0, &cached_state, GFP_NOFS);
1012 if (err == -ENOMEM)
1013 err = 0;
1014 if (!err)
1015 err = filemap_fdatawait_range(mapping, start, end);
1016 if (err)
1017 werr = err;
1018 free_extent_state(cached_state);
1019 cached_state = NULL;
1020 cond_resched();
1021 start = end + 1;
1022 }
1023 if (err)
1024 werr = err;
1025 return werr;
1026}
1027
1028int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1029 struct extent_io_tree *dirty_pages)
1030{
1031 bool errors = false;
1032 int err;
1033
1034 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1035 if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1036 errors = true;
1037
1038 if (errors && !err)
1039 err = -EIO;
1040 return err;
1041}
1042
1043int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1044{
1045 struct btrfs_fs_info *fs_info = log_root->fs_info;
1046 struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1047 bool errors = false;
1048 int err;
1049
1050 ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1051
1052 err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1053 if ((mark & EXTENT_DIRTY) &&
1054 test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1055 errors = true;
1056
1057 if ((mark & EXTENT_NEW) &&
1058 test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1059 errors = true;
1060
1061 if (errors && !err)
1062 err = -EIO;
1063 return err;
1064}
1065
1066/*
1067 * when btree blocks are allocated, they have some corresponding bits set for
1068 * them in one of two extent_io trees. This is used to make sure all of
1069 * those extents are on disk for transaction or log commit
1070 */
1071static int btrfs_write_and_wait_marked_extents(struct btrfs_fs_info *fs_info,
1072 struct extent_io_tree *dirty_pages, int mark)
1073{
1074 int ret;
1075 int ret2;
1076 struct blk_plug plug;
1077
1078 blk_start_plug(&plug);
1079 ret = btrfs_write_marked_extents(fs_info, dirty_pages, mark);
1080 blk_finish_plug(&plug);
1081 ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1082
1083 if (ret)
1084 return ret;
1085 if (ret2)
1086 return ret2;
1087 return 0;
1088}
1089
1090static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
1091 struct btrfs_fs_info *fs_info)
1092{
1093 int ret;
1094
1095 ret = btrfs_write_and_wait_marked_extents(fs_info,
1096 &trans->transaction->dirty_pages,
1097 EXTENT_DIRTY);
1098 clear_btree_io_tree(&trans->transaction->dirty_pages);
1099
1100 return ret;
1101}
1102
1103/*
1104 * this is used to update the root pointer in the tree of tree roots.
1105 *
1106 * But, in the case of the extent allocation tree, updating the root
1107 * pointer may allocate blocks which may change the root of the extent
1108 * allocation tree.
1109 *
1110 * So, this loops and repeats and makes sure the cowonly root didn't
1111 * change while the root pointer was being updated in the metadata.
1112 */
1113static int update_cowonly_root(struct btrfs_trans_handle *trans,
1114 struct btrfs_root *root)
1115{
1116 int ret;
1117 u64 old_root_bytenr;
1118 u64 old_root_used;
1119 struct btrfs_fs_info *fs_info = root->fs_info;
1120 struct btrfs_root *tree_root = fs_info->tree_root;
1121
1122 old_root_used = btrfs_root_used(&root->root_item);
1123
1124 while (1) {
1125 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1126 if (old_root_bytenr == root->node->start &&
1127 old_root_used == btrfs_root_used(&root->root_item))
1128 break;
1129
1130 btrfs_set_root_node(&root->root_item, root->node);
1131 ret = btrfs_update_root(trans, tree_root,
1132 &root->root_key,
1133 &root->root_item);
1134 if (ret)
1135 return ret;
1136
1137 old_root_used = btrfs_root_used(&root->root_item);
1138 }
1139
1140 return 0;
1141}
1142
1143/*
1144 * update all the cowonly tree roots on disk
1145 *
1146 * The error handling in this function may not be obvious. Any of the
1147 * failures will cause the file system to go offline. We still need
1148 * to clean up the delayed refs.
1149 */
1150static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
1151 struct btrfs_fs_info *fs_info)
1152{
1153 struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1154 struct list_head *io_bgs = &trans->transaction->io_bgs;
1155 struct list_head *next;
1156 struct extent_buffer *eb;
1157 int ret;
1158
1159 eb = btrfs_lock_root_node(fs_info->tree_root);
1160 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1161 0, &eb);
1162 btrfs_tree_unlock(eb);
1163 free_extent_buffer(eb);
1164
1165 if (ret)
1166 return ret;
1167
1168 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1169 if (ret)
1170 return ret;
1171
1172 ret = btrfs_run_dev_stats(trans, fs_info);
1173 if (ret)
1174 return ret;
1175 ret = btrfs_run_dev_replace(trans, fs_info);
1176 if (ret)
1177 return ret;
1178 ret = btrfs_run_qgroups(trans, fs_info);
1179 if (ret)
1180 return ret;
1181
1182 ret = btrfs_setup_space_cache(trans, fs_info);
1183 if (ret)
1184 return ret;
1185
1186 /* run_qgroups might have added some more refs */
1187 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1188 if (ret)
1189 return ret;
1190again:
1191 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1192 struct btrfs_root *root;
1193 next = fs_info->dirty_cowonly_roots.next;
1194 list_del_init(next);
1195 root = list_entry(next, struct btrfs_root, dirty_list);
1196 clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1197
1198 if (root != fs_info->extent_root)
1199 list_add_tail(&root->dirty_list,
1200 &trans->transaction->switch_commits);
1201 ret = update_cowonly_root(trans, root);
1202 if (ret)
1203 return ret;
1204 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1205 if (ret)
1206 return ret;
1207 }
1208
1209 while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1210 ret = btrfs_write_dirty_block_groups(trans, fs_info);
1211 if (ret)
1212 return ret;
1213 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1214 if (ret)
1215 return ret;
1216 }
1217
1218 if (!list_empty(&fs_info->dirty_cowonly_roots))
1219 goto again;
1220
1221 list_add_tail(&fs_info->extent_root->dirty_list,
1222 &trans->transaction->switch_commits);
1223 btrfs_after_dev_replace_commit(fs_info);
1224
1225 return 0;
1226}
1227
1228/*
1229 * dead roots are old snapshots that need to be deleted. This allocates
1230 * a dirty root struct and adds it into the list of dead roots that need to
1231 * be deleted
1232 */
1233void btrfs_add_dead_root(struct btrfs_root *root)
1234{
1235 struct btrfs_fs_info *fs_info = root->fs_info;
1236
1237 spin_lock(&fs_info->trans_lock);
1238 if (list_empty(&root->root_list))
1239 list_add_tail(&root->root_list, &fs_info->dead_roots);
1240 spin_unlock(&fs_info->trans_lock);
1241}
1242
1243/*
1244 * update all the cowonly tree roots on disk
1245 */
1246static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
1247 struct btrfs_fs_info *fs_info)
1248{
1249 struct btrfs_root *gang[8];
1250 int i;
1251 int ret;
1252 int err = 0;
1253
1254 spin_lock(&fs_info->fs_roots_radix_lock);
1255 while (1) {
1256 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1257 (void **)gang, 0,
1258 ARRAY_SIZE(gang),
1259 BTRFS_ROOT_TRANS_TAG);
1260 if (ret == 0)
1261 break;
1262 for (i = 0; i < ret; i++) {
1263 struct btrfs_root *root = gang[i];
1264 radix_tree_tag_clear(&fs_info->fs_roots_radix,
1265 (unsigned long)root->root_key.objectid,
1266 BTRFS_ROOT_TRANS_TAG);
1267 spin_unlock(&fs_info->fs_roots_radix_lock);
1268
1269 btrfs_free_log(trans, root);
1270 btrfs_update_reloc_root(trans, root);
1271 btrfs_orphan_commit_root(trans, root);
1272
1273 btrfs_save_ino_cache(root, trans);
1274
1275 /* see comments in should_cow_block() */
1276 clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1277 smp_mb__after_atomic();
1278
1279 if (root->commit_root != root->node) {
1280 list_add_tail(&root->dirty_list,
1281 &trans->transaction->switch_commits);
1282 btrfs_set_root_node(&root->root_item,
1283 root->node);
1284 }
1285
1286 err = btrfs_update_root(trans, fs_info->tree_root,
1287 &root->root_key,
1288 &root->root_item);
1289 spin_lock(&fs_info->fs_roots_radix_lock);
1290 if (err)
1291 break;
1292 btrfs_qgroup_free_meta_all(root);
1293 }
1294 }
1295 spin_unlock(&fs_info->fs_roots_radix_lock);
1296 return err;
1297}
1298
1299/*
1300 * defrag a given btree.
1301 * Every leaf in the btree is read and defragged.
1302 */
1303int btrfs_defrag_root(struct btrfs_root *root)
1304{
1305 struct btrfs_fs_info *info = root->fs_info;
1306 struct btrfs_trans_handle *trans;
1307 int ret;
1308
1309 if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1310 return 0;
1311
1312 while (1) {
1313 trans = btrfs_start_transaction(root, 0);
1314 if (IS_ERR(trans))
1315 return PTR_ERR(trans);
1316
1317 ret = btrfs_defrag_leaves(trans, root);
1318
1319 btrfs_end_transaction(trans);
1320 btrfs_btree_balance_dirty(info);
1321 cond_resched();
1322
1323 if (btrfs_fs_closing(info) || ret != -EAGAIN)
1324 break;
1325
1326 if (btrfs_defrag_cancelled(info)) {
1327 btrfs_debug(info, "defrag_root cancelled");
1328 ret = -EAGAIN;
1329 break;
1330 }
1331 }
1332 clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1333 return ret;
1334}
1335
1336/*
1337 * Do all special snapshot related qgroup dirty hack.
1338 *
1339 * Will do all needed qgroup inherit and dirty hack like switch commit
1340 * roots inside one transaction and write all btree into disk, to make
1341 * qgroup works.
1342 */
1343static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1344 struct btrfs_root *src,
1345 struct btrfs_root *parent,
1346 struct btrfs_qgroup_inherit *inherit,
1347 u64 dst_objectid)
1348{
1349 struct btrfs_fs_info *fs_info = src->fs_info;
1350 int ret;
1351
1352 /*
1353 * Save some performance in the case that qgroups are not
1354 * enabled. If this check races with the ioctl, rescan will
1355 * kick in anyway.
1356 */
1357 mutex_lock(&fs_info->qgroup_ioctl_lock);
1358 if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags)) {
1359 mutex_unlock(&fs_info->qgroup_ioctl_lock);
1360 return 0;
1361 }
1362 mutex_unlock(&fs_info->qgroup_ioctl_lock);
1363
1364 /*
1365 * We are going to commit transaction, see btrfs_commit_transaction()
1366 * comment for reason locking tree_log_mutex
1367 */
1368 mutex_lock(&fs_info->tree_log_mutex);
1369
1370 ret = commit_fs_roots(trans, fs_info);
1371 if (ret)
1372 goto out;
1373 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info);
1374 if (ret < 0)
1375 goto out;
1376 ret = btrfs_qgroup_account_extents(trans, fs_info);
1377 if (ret < 0)
1378 goto out;
1379
1380 /* Now qgroup are all updated, we can inherit it to new qgroups */
1381 ret = btrfs_qgroup_inherit(trans, fs_info,
1382 src->root_key.objectid, dst_objectid,
1383 inherit);
1384 if (ret < 0)
1385 goto out;
1386
1387 /*
1388 * Now we do a simplified commit transaction, which will:
1389 * 1) commit all subvolume and extent tree
1390 * To ensure all subvolume and extent tree have a valid
1391 * commit_root to accounting later insert_dir_item()
1392 * 2) write all btree blocks onto disk
1393 * This is to make sure later btree modification will be cowed
1394 * Or commit_root can be populated and cause wrong qgroup numbers
1395 * In this simplified commit, we don't really care about other trees
1396 * like chunk and root tree, as they won't affect qgroup.
1397 * And we don't write super to avoid half committed status.
1398 */
1399 ret = commit_cowonly_roots(trans, fs_info);
1400 if (ret)
1401 goto out;
1402 switch_commit_roots(trans->transaction, fs_info);
1403 ret = btrfs_write_and_wait_transaction(trans, fs_info);
1404 if (ret)
1405 btrfs_handle_fs_error(fs_info, ret,
1406 "Error while writing out transaction for qgroup");
1407
1408out:
1409 mutex_unlock(&fs_info->tree_log_mutex);
1410
1411 /*
1412 * Force parent root to be updated, as we recorded it before so its
1413 * last_trans == cur_transid.
1414 * Or it won't be committed again onto disk after later
1415 * insert_dir_item()
1416 */
1417 if (!ret)
1418 record_root_in_trans(trans, parent, 1);
1419 return ret;
1420}
1421
1422/*
1423 * new snapshots need to be created at a very specific time in the
1424 * transaction commit. This does the actual creation.
1425 *
1426 * Note:
1427 * If the error which may affect the commitment of the current transaction
1428 * happens, we should return the error number. If the error which just affect
1429 * the creation of the pending snapshots, just return 0.
1430 */
1431static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1432 struct btrfs_fs_info *fs_info,
1433 struct btrfs_pending_snapshot *pending)
1434{
1435 struct btrfs_key key;
1436 struct btrfs_root_item *new_root_item;
1437 struct btrfs_root *tree_root = fs_info->tree_root;
1438 struct btrfs_root *root = pending->root;
1439 struct btrfs_root *parent_root;
1440 struct btrfs_block_rsv *rsv;
1441 struct inode *parent_inode;
1442 struct btrfs_path *path;
1443 struct btrfs_dir_item *dir_item;
1444 struct dentry *dentry;
1445 struct extent_buffer *tmp;
1446 struct extent_buffer *old;
1447 struct timespec cur_time;
1448 int ret = 0;
1449 u64 to_reserve = 0;
1450 u64 index = 0;
1451 u64 objectid;
1452 u64 root_flags;
1453 uuid_le new_uuid;
1454
1455 ASSERT(pending->path);
1456 path = pending->path;
1457
1458 ASSERT(pending->root_item);
1459 new_root_item = pending->root_item;
1460
1461 pending->error = btrfs_find_free_objectid(tree_root, &objectid);
1462 if (pending->error)
1463 goto no_free_objectid;
1464
1465 /*
1466 * Make qgroup to skip current new snapshot's qgroupid, as it is
1467 * accounted by later btrfs_qgroup_inherit().
1468 */
1469 btrfs_set_skip_qgroup(trans, objectid);
1470
1471 btrfs_reloc_pre_snapshot(pending, &to_reserve);
1472
1473 if (to_reserve > 0) {
1474 pending->error = btrfs_block_rsv_add(root,
1475 &pending->block_rsv,
1476 to_reserve,
1477 BTRFS_RESERVE_NO_FLUSH);
1478 if (pending->error)
1479 goto clear_skip_qgroup;
1480 }
1481
1482 key.objectid = objectid;
1483 key.offset = (u64)-1;
1484 key.type = BTRFS_ROOT_ITEM_KEY;
1485
1486 rsv = trans->block_rsv;
1487 trans->block_rsv = &pending->block_rsv;
1488 trans->bytes_reserved = trans->block_rsv->reserved;
1489 trace_btrfs_space_reservation(fs_info, "transaction",
1490 trans->transid,
1491 trans->bytes_reserved, 1);
1492 dentry = pending->dentry;
1493 parent_inode = pending->dir;
1494 parent_root = BTRFS_I(parent_inode)->root;
1495 record_root_in_trans(trans, parent_root, 0);
1496
1497 cur_time = current_time(parent_inode);
1498
1499 /*
1500 * insert the directory item
1501 */
1502 ret = btrfs_set_inode_index(parent_inode, &index);
1503 BUG_ON(ret); /* -ENOMEM */
1504
1505 /* check if there is a file/dir which has the same name. */
1506 dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1507 btrfs_ino(parent_inode),
1508 dentry->d_name.name,
1509 dentry->d_name.len, 0);
1510 if (dir_item != NULL && !IS_ERR(dir_item)) {
1511 pending->error = -EEXIST;
1512 goto dir_item_existed;
1513 } else if (IS_ERR(dir_item)) {
1514 ret = PTR_ERR(dir_item);
1515 btrfs_abort_transaction(trans, ret);
1516 goto fail;
1517 }
1518 btrfs_release_path(path);
1519
1520 /*
1521 * pull in the delayed directory update
1522 * and the delayed inode item
1523 * otherwise we corrupt the FS during
1524 * snapshot
1525 */
1526 ret = btrfs_run_delayed_items(trans, fs_info);
1527 if (ret) { /* Transaction aborted */
1528 btrfs_abort_transaction(trans, ret);
1529 goto fail;
1530 }
1531
1532 record_root_in_trans(trans, root, 0);
1533 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1534 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1535 btrfs_check_and_init_root_item(new_root_item);
1536
1537 root_flags = btrfs_root_flags(new_root_item);
1538 if (pending->readonly)
1539 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1540 else
1541 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1542 btrfs_set_root_flags(new_root_item, root_flags);
1543
1544 btrfs_set_root_generation_v2(new_root_item,
1545 trans->transid);
1546 uuid_le_gen(&new_uuid);
1547 memcpy(new_root_item->uuid, new_uuid.b, BTRFS_UUID_SIZE);
1548 memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1549 BTRFS_UUID_SIZE);
1550 if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1551 memset(new_root_item->received_uuid, 0,
1552 sizeof(new_root_item->received_uuid));
1553 memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1554 memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1555 btrfs_set_root_stransid(new_root_item, 0);
1556 btrfs_set_root_rtransid(new_root_item, 0);
1557 }
1558 btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1559 btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1560 btrfs_set_root_otransid(new_root_item, trans->transid);
1561
1562 old = btrfs_lock_root_node(root);
1563 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
1564 if (ret) {
1565 btrfs_tree_unlock(old);
1566 free_extent_buffer(old);
1567 btrfs_abort_transaction(trans, ret);
1568 goto fail;
1569 }
1570
1571 btrfs_set_lock_blocking(old);
1572
1573 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1574 /* clean up in any case */
1575 btrfs_tree_unlock(old);
1576 free_extent_buffer(old);
1577 if (ret) {
1578 btrfs_abort_transaction(trans, ret);
1579 goto fail;
1580 }
1581 /* see comments in should_cow_block() */
1582 set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1583 smp_wmb();
1584
1585 btrfs_set_root_node(new_root_item, tmp);
1586 /* record when the snapshot was created in key.offset */
1587 key.offset = trans->transid;
1588 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1589 btrfs_tree_unlock(tmp);
1590 free_extent_buffer(tmp);
1591 if (ret) {
1592 btrfs_abort_transaction(trans, ret);
1593 goto fail;
1594 }
1595
1596 /*
1597 * insert root back/forward references
1598 */
1599 ret = btrfs_add_root_ref(trans, fs_info, objectid,
1600 parent_root->root_key.objectid,
1601 btrfs_ino(parent_inode), index,
1602 dentry->d_name.name, dentry->d_name.len);
1603 if (ret) {
1604 btrfs_abort_transaction(trans, ret);
1605 goto fail;
1606 }
1607
1608 key.offset = (u64)-1;
1609 pending->snap = btrfs_read_fs_root_no_name(fs_info, &key);
1610 if (IS_ERR(pending->snap)) {
1611 ret = PTR_ERR(pending->snap);
1612 btrfs_abort_transaction(trans, ret);
1613 goto fail;
1614 }
1615
1616 ret = btrfs_reloc_post_snapshot(trans, pending);
1617 if (ret) {
1618 btrfs_abort_transaction(trans, ret);
1619 goto fail;
1620 }
1621
1622 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1623 if (ret) {
1624 btrfs_abort_transaction(trans, ret);
1625 goto fail;
1626 }
1627
1628 /*
1629 * Do special qgroup accounting for snapshot, as we do some qgroup
1630 * snapshot hack to do fast snapshot.
1631 * To co-operate with that hack, we do hack again.
1632 * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1633 */
1634 ret = qgroup_account_snapshot(trans, root, parent_root,
1635 pending->inherit, objectid);
1636 if (ret < 0)
1637 goto fail;
1638
1639 ret = btrfs_insert_dir_item(trans, parent_root,
1640 dentry->d_name.name, dentry->d_name.len,
1641 parent_inode, &key,
1642 BTRFS_FT_DIR, index);
1643 /* We have check then name at the beginning, so it is impossible. */
1644 BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1645 if (ret) {
1646 btrfs_abort_transaction(trans, ret);
1647 goto fail;
1648 }
1649
1650 btrfs_i_size_write(parent_inode, parent_inode->i_size +
1651 dentry->d_name.len * 2);
1652 parent_inode->i_mtime = parent_inode->i_ctime =
1653 current_time(parent_inode);
1654 ret = btrfs_update_inode_fallback(trans, parent_root, parent_inode);
1655 if (ret) {
1656 btrfs_abort_transaction(trans, ret);
1657 goto fail;
1658 }
1659 ret = btrfs_uuid_tree_add(trans, fs_info, new_uuid.b,
1660 BTRFS_UUID_KEY_SUBVOL, objectid);
1661 if (ret) {
1662 btrfs_abort_transaction(trans, ret);
1663 goto fail;
1664 }
1665 if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1666 ret = btrfs_uuid_tree_add(trans, fs_info,
1667 new_root_item->received_uuid,
1668 BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1669 objectid);
1670 if (ret && ret != -EEXIST) {
1671 btrfs_abort_transaction(trans, ret);
1672 goto fail;
1673 }
1674 }
1675
1676 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
1677 if (ret) {
1678 btrfs_abort_transaction(trans, ret);
1679 goto fail;
1680 }
1681
1682fail:
1683 pending->error = ret;
1684dir_item_existed:
1685 trans->block_rsv = rsv;
1686 trans->bytes_reserved = 0;
1687clear_skip_qgroup:
1688 btrfs_clear_skip_qgroup(trans);
1689no_free_objectid:
1690 kfree(new_root_item);
1691 pending->root_item = NULL;
1692 btrfs_free_path(path);
1693 pending->path = NULL;
1694
1695 return ret;
1696}
1697
1698/*
1699 * create all the snapshots we've scheduled for creation
1700 */
1701static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1702 struct btrfs_fs_info *fs_info)
1703{
1704 struct btrfs_pending_snapshot *pending, *next;
1705 struct list_head *head = &trans->transaction->pending_snapshots;
1706 int ret = 0;
1707
1708 list_for_each_entry_safe(pending, next, head, list) {
1709 list_del(&pending->list);
1710 ret = create_pending_snapshot(trans, fs_info, pending);
1711 if (ret)
1712 break;
1713 }
1714 return ret;
1715}
1716
1717static void update_super_roots(struct btrfs_fs_info *fs_info)
1718{
1719 struct btrfs_root_item *root_item;
1720 struct btrfs_super_block *super;
1721
1722 super = fs_info->super_copy;
1723
1724 root_item = &fs_info->chunk_root->root_item;
1725 super->chunk_root = root_item->bytenr;
1726 super->chunk_root_generation = root_item->generation;
1727 super->chunk_root_level = root_item->level;
1728
1729 root_item = &fs_info->tree_root->root_item;
1730 super->root = root_item->bytenr;
1731 super->generation = root_item->generation;
1732 super->root_level = root_item->level;
1733 if (btrfs_test_opt(fs_info, SPACE_CACHE))
1734 super->cache_generation = root_item->generation;
1735 if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1736 super->uuid_tree_generation = root_item->generation;
1737}
1738
1739int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1740{
1741 struct btrfs_transaction *trans;
1742 int ret = 0;
1743
1744 spin_lock(&info->trans_lock);
1745 trans = info->running_transaction;
1746 if (trans)
1747 ret = (trans->state >= TRANS_STATE_COMMIT_START);
1748 spin_unlock(&info->trans_lock);
1749 return ret;
1750}
1751
1752int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1753{
1754 struct btrfs_transaction *trans;
1755 int ret = 0;
1756
1757 spin_lock(&info->trans_lock);
1758 trans = info->running_transaction;
1759 if (trans)
1760 ret = is_transaction_blocked(trans);
1761 spin_unlock(&info->trans_lock);
1762 return ret;
1763}
1764
1765/*
1766 * wait for the current transaction commit to start and block subsequent
1767 * transaction joins
1768 */
1769static void wait_current_trans_commit_start(struct btrfs_fs_info *fs_info,
1770 struct btrfs_transaction *trans)
1771{
1772 wait_event(fs_info->transaction_blocked_wait,
1773 trans->state >= TRANS_STATE_COMMIT_START || trans->aborted);
1774}
1775
1776/*
1777 * wait for the current transaction to start and then become unblocked.
1778 * caller holds ref.
1779 */
1780static void wait_current_trans_commit_start_and_unblock(
1781 struct btrfs_fs_info *fs_info,
1782 struct btrfs_transaction *trans)
1783{
1784 wait_event(fs_info->transaction_wait,
1785 trans->state >= TRANS_STATE_UNBLOCKED || trans->aborted);
1786}
1787
1788/*
1789 * commit transactions asynchronously. once btrfs_commit_transaction_async
1790 * returns, any subsequent transaction will not be allowed to join.
1791 */
1792struct btrfs_async_commit {
1793 struct btrfs_trans_handle *newtrans;
1794 struct work_struct work;
1795};
1796
1797static void do_async_commit(struct work_struct *work)
1798{
1799 struct btrfs_async_commit *ac =
1800 container_of(work, struct btrfs_async_commit, work);
1801
1802 /*
1803 * We've got freeze protection passed with the transaction.
1804 * Tell lockdep about it.
1805 */
1806 if (ac->newtrans->type & __TRANS_FREEZABLE)
1807 __sb_writers_acquired(ac->newtrans->fs_info->sb, SB_FREEZE_FS);
1808
1809 current->journal_info = ac->newtrans;
1810
1811 btrfs_commit_transaction(ac->newtrans);
1812 kfree(ac);
1813}
1814
1815int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1816 int wait_for_unblock)
1817{
1818 struct btrfs_fs_info *fs_info = trans->fs_info;
1819 struct btrfs_async_commit *ac;
1820 struct btrfs_transaction *cur_trans;
1821
1822 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1823 if (!ac)
1824 return -ENOMEM;
1825
1826 INIT_WORK(&ac->work, do_async_commit);
1827 ac->newtrans = btrfs_join_transaction(trans->root);
1828 if (IS_ERR(ac->newtrans)) {
1829 int err = PTR_ERR(ac->newtrans);
1830 kfree(ac);
1831 return err;
1832 }
1833
1834 /* take transaction reference */
1835 cur_trans = trans->transaction;
1836 atomic_inc(&cur_trans->use_count);
1837
1838 btrfs_end_transaction(trans);
1839
1840 /*
1841 * Tell lockdep we've released the freeze rwsem, since the
1842 * async commit thread will be the one to unlock it.
1843 */
1844 if (ac->newtrans->type & __TRANS_FREEZABLE)
1845 __sb_writers_release(fs_info->sb, SB_FREEZE_FS);
1846
1847 schedule_work(&ac->work);
1848
1849 /* wait for transaction to start and unblock */
1850 if (wait_for_unblock)
1851 wait_current_trans_commit_start_and_unblock(fs_info, cur_trans);
1852 else
1853 wait_current_trans_commit_start(fs_info, cur_trans);
1854
1855 if (current->journal_info == trans)
1856 current->journal_info = NULL;
1857
1858 btrfs_put_transaction(cur_trans);
1859 return 0;
1860}
1861
1862
1863static void cleanup_transaction(struct btrfs_trans_handle *trans,
1864 struct btrfs_root *root, int err)
1865{
1866 struct btrfs_fs_info *fs_info = root->fs_info;
1867 struct btrfs_transaction *cur_trans = trans->transaction;
1868 DEFINE_WAIT(wait);
1869
1870 WARN_ON(trans->use_count > 1);
1871
1872 btrfs_abort_transaction(trans, err);
1873
1874 spin_lock(&fs_info->trans_lock);
1875
1876 /*
1877 * If the transaction is removed from the list, it means this
1878 * transaction has been committed successfully, so it is impossible
1879 * to call the cleanup function.
1880 */
1881 BUG_ON(list_empty(&cur_trans->list));
1882
1883 list_del_init(&cur_trans->list);
1884 if (cur_trans == fs_info->running_transaction) {
1885 cur_trans->state = TRANS_STATE_COMMIT_DOING;
1886 spin_unlock(&fs_info->trans_lock);
1887 wait_event(cur_trans->writer_wait,
1888 atomic_read(&cur_trans->num_writers) == 1);
1889
1890 spin_lock(&fs_info->trans_lock);
1891 }
1892 spin_unlock(&fs_info->trans_lock);
1893
1894 btrfs_cleanup_one_transaction(trans->transaction, fs_info);
1895
1896 spin_lock(&fs_info->trans_lock);
1897 if (cur_trans == fs_info->running_transaction)
1898 fs_info->running_transaction = NULL;
1899 spin_unlock(&fs_info->trans_lock);
1900
1901 if (trans->type & __TRANS_FREEZABLE)
1902 sb_end_intwrite(fs_info->sb);
1903 btrfs_put_transaction(cur_trans);
1904 btrfs_put_transaction(cur_trans);
1905
1906 trace_btrfs_transaction_commit(root);
1907
1908 if (current->journal_info == trans)
1909 current->journal_info = NULL;
1910 btrfs_scrub_cancel(fs_info);
1911
1912 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1913}
1914
1915static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
1916{
1917 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1918 return btrfs_start_delalloc_roots(fs_info, 1, -1);
1919 return 0;
1920}
1921
1922static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
1923{
1924 if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
1925 btrfs_wait_ordered_roots(fs_info, -1, 0, (u64)-1);
1926}
1927
1928static inline void
1929btrfs_wait_pending_ordered(struct btrfs_transaction *cur_trans)
1930{
1931 wait_event(cur_trans->pending_wait,
1932 atomic_read(&cur_trans->pending_ordered) == 0);
1933}
1934
1935int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
1936{
1937 struct btrfs_fs_info *fs_info = trans->fs_info;
1938 struct btrfs_transaction *cur_trans = trans->transaction;
1939 struct btrfs_transaction *prev_trans = NULL;
1940 int ret;
1941
1942 /* Stop the commit early if ->aborted is set */
1943 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
1944 ret = cur_trans->aborted;
1945 btrfs_end_transaction(trans);
1946 return ret;
1947 }
1948
1949 /* make a pass through all the delayed refs we have so far
1950 * any runnings procs may add more while we are here
1951 */
1952 ret = btrfs_run_delayed_refs(trans, fs_info, 0);
1953 if (ret) {
1954 btrfs_end_transaction(trans);
1955 return ret;
1956 }
1957
1958 btrfs_trans_release_metadata(trans, fs_info);
1959 trans->block_rsv = NULL;
1960
1961 cur_trans = trans->transaction;
1962
1963 /*
1964 * set the flushing flag so procs in this transaction have to
1965 * start sending their work down.
1966 */
1967 cur_trans->delayed_refs.flushing = 1;
1968 smp_wmb();
1969
1970 if (!list_empty(&trans->new_bgs))
1971 btrfs_create_pending_block_groups(trans, fs_info);
1972
1973 ret = btrfs_run_delayed_refs(trans, fs_info, 0);
1974 if (ret) {
1975 btrfs_end_transaction(trans);
1976 return ret;
1977 }
1978
1979 if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
1980 int run_it = 0;
1981
1982 /* this mutex is also taken before trying to set
1983 * block groups readonly. We need to make sure
1984 * that nobody has set a block group readonly
1985 * after a extents from that block group have been
1986 * allocated for cache files. btrfs_set_block_group_ro
1987 * will wait for the transaction to commit if it
1988 * finds BTRFS_TRANS_DIRTY_BG_RUN set.
1989 *
1990 * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
1991 * only one process starts all the block group IO. It wouldn't
1992 * hurt to have more than one go through, but there's no
1993 * real advantage to it either.
1994 */
1995 mutex_lock(&fs_info->ro_block_group_mutex);
1996 if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
1997 &cur_trans->flags))
1998 run_it = 1;
1999 mutex_unlock(&fs_info->ro_block_group_mutex);
2000
2001 if (run_it)
2002 ret = btrfs_start_dirty_block_groups(trans, fs_info);
2003 }
2004 if (ret) {
2005 btrfs_end_transaction(trans);
2006 return ret;
2007 }
2008
2009 spin_lock(&fs_info->trans_lock);
2010 if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2011 spin_unlock(&fs_info->trans_lock);
2012 atomic_inc(&cur_trans->use_count);
2013 ret = btrfs_end_transaction(trans);
2014
2015 wait_for_commit(cur_trans);
2016
2017 if (unlikely(cur_trans->aborted))
2018 ret = cur_trans->aborted;
2019
2020 btrfs_put_transaction(cur_trans);
2021
2022 return ret;
2023 }
2024
2025 cur_trans->state = TRANS_STATE_COMMIT_START;
2026 wake_up(&fs_info->transaction_blocked_wait);
2027
2028 if (cur_trans->list.prev != &fs_info->trans_list) {
2029 prev_trans = list_entry(cur_trans->list.prev,
2030 struct btrfs_transaction, list);
2031 if (prev_trans->state != TRANS_STATE_COMPLETED) {
2032 atomic_inc(&prev_trans->use_count);
2033 spin_unlock(&fs_info->trans_lock);
2034
2035 wait_for_commit(prev_trans);
2036 ret = prev_trans->aborted;
2037
2038 btrfs_put_transaction(prev_trans);
2039 if (ret)
2040 goto cleanup_transaction;
2041 } else {
2042 spin_unlock(&fs_info->trans_lock);
2043 }
2044 } else {
2045 spin_unlock(&fs_info->trans_lock);
2046 }
2047
2048 extwriter_counter_dec(cur_trans, trans->type);
2049
2050 ret = btrfs_start_delalloc_flush(fs_info);
2051 if (ret)
2052 goto cleanup_transaction;
2053
2054 ret = btrfs_run_delayed_items(trans, fs_info);
2055 if (ret)
2056 goto cleanup_transaction;
2057
2058 wait_event(cur_trans->writer_wait,
2059 extwriter_counter_read(cur_trans) == 0);
2060
2061 /* some pending stuffs might be added after the previous flush. */
2062 ret = btrfs_run_delayed_items(trans, fs_info);
2063 if (ret)
2064 goto cleanup_transaction;
2065
2066 btrfs_wait_delalloc_flush(fs_info);
2067
2068 btrfs_wait_pending_ordered(cur_trans);
2069
2070 btrfs_scrub_pause(fs_info);
2071 /*
2072 * Ok now we need to make sure to block out any other joins while we
2073 * commit the transaction. We could have started a join before setting
2074 * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2075 */
2076 spin_lock(&fs_info->trans_lock);
2077 cur_trans->state = TRANS_STATE_COMMIT_DOING;
2078 spin_unlock(&fs_info->trans_lock);
2079 wait_event(cur_trans->writer_wait,
2080 atomic_read(&cur_trans->num_writers) == 1);
2081
2082 /* ->aborted might be set after the previous check, so check it */
2083 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
2084 ret = cur_trans->aborted;
2085 goto scrub_continue;
2086 }
2087 /*
2088 * the reloc mutex makes sure that we stop
2089 * the balancing code from coming in and moving
2090 * extents around in the middle of the commit
2091 */
2092 mutex_lock(&fs_info->reloc_mutex);
2093
2094 /*
2095 * We needn't worry about the delayed items because we will
2096 * deal with them in create_pending_snapshot(), which is the
2097 * core function of the snapshot creation.
2098 */
2099 ret = create_pending_snapshots(trans, fs_info);
2100 if (ret) {
2101 mutex_unlock(&fs_info->reloc_mutex);
2102 goto scrub_continue;
2103 }
2104
2105 /*
2106 * We insert the dir indexes of the snapshots and update the inode
2107 * of the snapshots' parents after the snapshot creation, so there
2108 * are some delayed items which are not dealt with. Now deal with
2109 * them.
2110 *
2111 * We needn't worry that this operation will corrupt the snapshots,
2112 * because all the tree which are snapshoted will be forced to COW
2113 * the nodes and leaves.
2114 */
2115 ret = btrfs_run_delayed_items(trans, fs_info);
2116 if (ret) {
2117 mutex_unlock(&fs_info->reloc_mutex);
2118 goto scrub_continue;
2119 }
2120
2121 ret = btrfs_run_delayed_refs(trans, fs_info, (unsigned long)-1);
2122 if (ret) {
2123 mutex_unlock(&fs_info->reloc_mutex);
2124 goto scrub_continue;
2125 }
2126
2127 /* Reocrd old roots for later qgroup accounting */
2128 ret = btrfs_qgroup_prepare_account_extents(trans, fs_info);
2129 if (ret) {
2130 mutex_unlock(&fs_info->reloc_mutex);
2131 goto scrub_continue;
2132 }
2133
2134 /*
2135 * make sure none of the code above managed to slip in a
2136 * delayed item
2137 */
2138 btrfs_assert_delayed_root_empty(fs_info);
2139
2140 WARN_ON(cur_trans != trans->transaction);
2141
2142 /* btrfs_commit_tree_roots is responsible for getting the
2143 * various roots consistent with each other. Every pointer
2144 * in the tree of tree roots has to point to the most up to date
2145 * root for every subvolume and other tree. So, we have to keep
2146 * the tree logging code from jumping in and changing any
2147 * of the trees.
2148 *
2149 * At this point in the commit, there can't be any tree-log
2150 * writers, but a little lower down we drop the trans mutex
2151 * and let new people in. By holding the tree_log_mutex
2152 * from now until after the super is written, we avoid races
2153 * with the tree-log code.
2154 */
2155 mutex_lock(&fs_info->tree_log_mutex);
2156
2157 ret = commit_fs_roots(trans, fs_info);
2158 if (ret) {
2159 mutex_unlock(&fs_info->tree_log_mutex);
2160 mutex_unlock(&fs_info->reloc_mutex);
2161 goto scrub_continue;
2162 }
2163
2164 /*
2165 * Since the transaction is done, we can apply the pending changes
2166 * before the next transaction.
2167 */
2168 btrfs_apply_pending_changes(fs_info);
2169
2170 /* commit_fs_roots gets rid of all the tree log roots, it is now
2171 * safe to free the root of tree log roots
2172 */
2173 btrfs_free_log_root_tree(trans, fs_info);
2174
2175 /*
2176 * Since fs roots are all committed, we can get a quite accurate
2177 * new_roots. So let's do quota accounting.
2178 */
2179 ret = btrfs_qgroup_account_extents(trans, fs_info);
2180 if (ret < 0) {
2181 mutex_unlock(&fs_info->tree_log_mutex);
2182 mutex_unlock(&fs_info->reloc_mutex);
2183 goto scrub_continue;
2184 }
2185
2186 ret = commit_cowonly_roots(trans, fs_info);
2187 if (ret) {
2188 mutex_unlock(&fs_info->tree_log_mutex);
2189 mutex_unlock(&fs_info->reloc_mutex);
2190 goto scrub_continue;
2191 }
2192
2193 /*
2194 * The tasks which save the space cache and inode cache may also
2195 * update ->aborted, check it.
2196 */
2197 if (unlikely(ACCESS_ONCE(cur_trans->aborted))) {
2198 ret = cur_trans->aborted;
2199 mutex_unlock(&fs_info->tree_log_mutex);
2200 mutex_unlock(&fs_info->reloc_mutex);
2201 goto scrub_continue;
2202 }
2203
2204 btrfs_prepare_extent_commit(trans, fs_info);
2205
2206 cur_trans = fs_info->running_transaction;
2207
2208 btrfs_set_root_node(&fs_info->tree_root->root_item,
2209 fs_info->tree_root->node);
2210 list_add_tail(&fs_info->tree_root->dirty_list,
2211 &cur_trans->switch_commits);
2212
2213 btrfs_set_root_node(&fs_info->chunk_root->root_item,
2214 fs_info->chunk_root->node);
2215 list_add_tail(&fs_info->chunk_root->dirty_list,
2216 &cur_trans->switch_commits);
2217
2218 switch_commit_roots(cur_trans, fs_info);
2219
2220 assert_qgroups_uptodate(trans);
2221 ASSERT(list_empty(&cur_trans->dirty_bgs));
2222 ASSERT(list_empty(&cur_trans->io_bgs));
2223 update_super_roots(fs_info);
2224
2225 btrfs_set_super_log_root(fs_info->super_copy, 0);
2226 btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2227 memcpy(fs_info->super_for_commit, fs_info->super_copy,
2228 sizeof(*fs_info->super_copy));
2229
2230 btrfs_update_commit_device_size(fs_info);
2231 btrfs_update_commit_device_bytes_used(fs_info, cur_trans);
2232
2233 clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2234 clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2235
2236 btrfs_trans_release_chunk_metadata(trans);
2237
2238 spin_lock(&fs_info->trans_lock);
2239 cur_trans->state = TRANS_STATE_UNBLOCKED;
2240 fs_info->running_transaction = NULL;
2241 spin_unlock(&fs_info->trans_lock);
2242 mutex_unlock(&fs_info->reloc_mutex);
2243
2244 wake_up(&fs_info->transaction_wait);
2245
2246 ret = btrfs_write_and_wait_transaction(trans, fs_info);
2247 if (ret) {
2248 btrfs_handle_fs_error(fs_info, ret,
2249 "Error while writing out transaction");
2250 mutex_unlock(&fs_info->tree_log_mutex);
2251 goto scrub_continue;
2252 }
2253
2254 ret = write_ctree_super(trans, fs_info, 0);
2255 if (ret) {
2256 mutex_unlock(&fs_info->tree_log_mutex);
2257 goto scrub_continue;
2258 }
2259
2260 /*
2261 * the super is written, we can safely allow the tree-loggers
2262 * to go about their business
2263 */
2264 mutex_unlock(&fs_info->tree_log_mutex);
2265
2266 btrfs_finish_extent_commit(trans, fs_info);
2267
2268 if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2269 btrfs_clear_space_info_full(fs_info);
2270
2271 fs_info->last_trans_committed = cur_trans->transid;
2272 /*
2273 * We needn't acquire the lock here because there is no other task
2274 * which can change it.
2275 */
2276 cur_trans->state = TRANS_STATE_COMPLETED;
2277 wake_up(&cur_trans->commit_wait);
2278
2279 spin_lock(&fs_info->trans_lock);
2280 list_del_init(&cur_trans->list);
2281 spin_unlock(&fs_info->trans_lock);
2282
2283 btrfs_put_transaction(cur_trans);
2284 btrfs_put_transaction(cur_trans);
2285
2286 if (trans->type & __TRANS_FREEZABLE)
2287 sb_end_intwrite(fs_info->sb);
2288
2289 trace_btrfs_transaction_commit(trans->root);
2290
2291 btrfs_scrub_continue(fs_info);
2292
2293 if (current->journal_info == trans)
2294 current->journal_info = NULL;
2295
2296 kmem_cache_free(btrfs_trans_handle_cachep, trans);
2297
2298 /*
2299 * If fs has been frozen, we can not handle delayed iputs, otherwise
2300 * it'll result in deadlock about SB_FREEZE_FS.
2301 */
2302 if (current != fs_info->transaction_kthread &&
2303 current != fs_info->cleaner_kthread && !fs_info->fs_frozen)
2304 btrfs_run_delayed_iputs(fs_info);
2305
2306 return ret;
2307
2308scrub_continue:
2309 btrfs_scrub_continue(fs_info);
2310cleanup_transaction:
2311 btrfs_trans_release_metadata(trans, fs_info);
2312 btrfs_trans_release_chunk_metadata(trans);
2313 trans->block_rsv = NULL;
2314 btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2315 if (current->journal_info == trans)
2316 current->journal_info = NULL;
2317 cleanup_transaction(trans, trans->root, ret);
2318
2319 return ret;
2320}
2321
2322/*
2323 * return < 0 if error
2324 * 0 if there are no more dead_roots at the time of call
2325 * 1 there are more to be processed, call me again
2326 *
2327 * The return value indicates there are certainly more snapshots to delete, but
2328 * if there comes a new one during processing, it may return 0. We don't mind,
2329 * because btrfs_commit_super will poke cleaner thread and it will process it a
2330 * few seconds later.
2331 */
2332int btrfs_clean_one_deleted_snapshot(struct btrfs_root *root)
2333{
2334 int ret;
2335 struct btrfs_fs_info *fs_info = root->fs_info;
2336
2337 spin_lock(&fs_info->trans_lock);
2338 if (list_empty(&fs_info->dead_roots)) {
2339 spin_unlock(&fs_info->trans_lock);
2340 return 0;
2341 }
2342 root = list_first_entry(&fs_info->dead_roots,
2343 struct btrfs_root, root_list);
2344 list_del_init(&root->root_list);
2345 spin_unlock(&fs_info->trans_lock);
2346
2347 btrfs_debug(fs_info, "cleaner removing %llu", root->objectid);
2348
2349 btrfs_kill_all_delayed_nodes(root);
2350
2351 if (btrfs_header_backref_rev(root->node) <
2352 BTRFS_MIXED_BACKREF_REV)
2353 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
2354 else
2355 ret = btrfs_drop_snapshot(root, NULL, 1, 0);
2356
2357 return (ret < 0) ? 0 : 1;
2358}
2359
2360void btrfs_apply_pending_changes(struct btrfs_fs_info *fs_info)
2361{
2362 unsigned long prev;
2363 unsigned long bit;
2364
2365 prev = xchg(&fs_info->pending_changes, 0);
2366 if (!prev)
2367 return;
2368
2369 bit = 1 << BTRFS_PENDING_SET_INODE_MAP_CACHE;
2370 if (prev & bit)
2371 btrfs_set_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2372 prev &= ~bit;
2373
2374 bit = 1 << BTRFS_PENDING_CLEAR_INODE_MAP_CACHE;
2375 if (prev & bit)
2376 btrfs_clear_opt(fs_info->mount_opt, INODE_MAP_CACHE);
2377 prev &= ~bit;
2378
2379 bit = 1 << BTRFS_PENDING_COMMIT;
2380 if (prev & bit)
2381 btrfs_debug(fs_info, "pending commit done");
2382 prev &= ~bit;
2383
2384 if (prev)
2385 btrfs_warn(fs_info,
2386 "unknown pending changes left 0x%lx, ignoring", prev);
2387}