Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Copyright (C) 2007 Oracle. All rights reserved.
4 : */
5 :
6 : #include <linux/fs.h>
7 : #include <linux/slab.h>
8 : #include <linux/sched.h>
9 : #include <linux/sched/mm.h>
10 : #include <linux/writeback.h>
11 : #include <linux/pagemap.h>
12 : #include <linux/blkdev.h>
13 : #include <linux/uuid.h>
14 : #include <linux/timekeeping.h>
15 : #include "misc.h"
16 : #include "ctree.h"
17 : #include "disk-io.h"
18 : #include "transaction.h"
19 : #include "locking.h"
20 : #include "tree-log.h"
21 : #include "volumes.h"
22 : #include "dev-replace.h"
23 : #include "qgroup.h"
24 : #include "block-group.h"
25 : #include "space-info.h"
26 : #include "zoned.h"
27 : #include "fs.h"
28 : #include "accessors.h"
29 : #include "extent-tree.h"
30 : #include "root-tree.h"
31 : #include "defrag.h"
32 : #include "dir-item.h"
33 : #include "uuid-tree.h"
34 : #include "ioctl.h"
35 : #include "relocation.h"
36 : #include "scrub.h"
37 :
38 : static struct kmem_cache *btrfs_trans_handle_cachep;
39 :
40 : #define BTRFS_ROOT_TRANS_TAG 0
41 :
42 : /*
43 : * Transaction states and transitions
44 : *
45 : * No running transaction (fs tree blocks are not modified)
46 : * |
47 : * | To next stage:
48 : * | Call start_transaction() variants. Except btrfs_join_transaction_nostart().
49 : * V
50 : * Transaction N [[TRANS_STATE_RUNNING]]
51 : * |
52 : * | New trans handles can be attached to transaction N by calling all
53 : * | start_transaction() variants.
54 : * |
55 : * | To next stage:
56 : * | Call btrfs_commit_transaction() on any trans handle attached to
57 : * | transaction N
58 : * V
59 : * Transaction N [[TRANS_STATE_COMMIT_START]]
60 : * |
61 : * | Will wait for previous running transaction to completely finish if there
62 : * | is one
63 : * |
64 : * | Then one of the following happes:
65 : * | - Wait for all other trans handle holders to release.
66 : * | The btrfs_commit_transaction() caller will do the commit work.
67 : * | - Wait for current transaction to be committed by others.
68 : * | Other btrfs_commit_transaction() caller will do the commit work.
69 : * |
70 : * | At this stage, only btrfs_join_transaction*() variants can attach
71 : * | to this running transaction.
72 : * | All other variants will wait for current one to finish and attach to
73 : * | transaction N+1.
74 : * |
75 : * | To next stage:
76 : * | Caller is chosen to commit transaction N, and all other trans handle
77 : * | haven been released.
78 : * V
79 : * Transaction N [[TRANS_STATE_COMMIT_DOING]]
80 : * |
81 : * | The heavy lifting transaction work is started.
82 : * | From running delayed refs (modifying extent tree) to creating pending
83 : * | snapshots, running qgroups.
84 : * | In short, modify supporting trees to reflect modifications of subvolume
85 : * | trees.
86 : * |
87 : * | At this stage, all start_transaction() calls will wait for this
88 : * | transaction to finish and attach to transaction N+1.
89 : * |
90 : * | To next stage:
91 : * | Until all supporting trees are updated.
92 : * V
93 : * Transaction N [[TRANS_STATE_UNBLOCKED]]
94 : * | Transaction N+1
95 : * | All needed trees are modified, thus we only [[TRANS_STATE_RUNNING]]
96 : * | need to write them back to disk and update |
97 : * | super blocks. |
98 : * | |
99 : * | At this stage, new transaction is allowed to |
100 : * | start. |
101 : * | All new start_transaction() calls will be |
102 : * | attached to transid N+1. |
103 : * | |
104 : * | To next stage: |
105 : * | Until all tree blocks are super blocks are |
106 : * | written to block devices |
107 : * V |
108 : * Transaction N [[TRANS_STATE_COMPLETED]] V
109 : * All tree blocks and super blocks are written. Transaction N+1
110 : * This transaction is finished and all its [[TRANS_STATE_COMMIT_START]]
111 : * data structures will be cleaned up. | Life goes on
112 : */
113 : static const unsigned int btrfs_blocked_trans_types[TRANS_STATE_MAX] = {
114 : [TRANS_STATE_RUNNING] = 0U,
115 : [TRANS_STATE_COMMIT_START] = (__TRANS_START | __TRANS_ATTACH),
116 : [TRANS_STATE_COMMIT_DOING] = (__TRANS_START |
117 : __TRANS_ATTACH |
118 : __TRANS_JOIN |
119 : __TRANS_JOIN_NOSTART),
120 : [TRANS_STATE_UNBLOCKED] = (__TRANS_START |
121 : __TRANS_ATTACH |
122 : __TRANS_JOIN |
123 : __TRANS_JOIN_NOLOCK |
124 : __TRANS_JOIN_NOSTART),
125 : [TRANS_STATE_SUPER_COMMITTED] = (__TRANS_START |
126 : __TRANS_ATTACH |
127 : __TRANS_JOIN |
128 : __TRANS_JOIN_NOLOCK |
129 : __TRANS_JOIN_NOSTART),
130 : [TRANS_STATE_COMPLETED] = (__TRANS_START |
131 : __TRANS_ATTACH |
132 : __TRANS_JOIN |
133 : __TRANS_JOIN_NOLOCK |
134 : __TRANS_JOIN_NOSTART),
135 : };
136 :
137 0 : void btrfs_put_transaction(struct btrfs_transaction *transaction)
138 : {
139 0 : WARN_ON(refcount_read(&transaction->use_count) == 0);
140 0 : if (refcount_dec_and_test(&transaction->use_count)) {
141 0 : BUG_ON(!list_empty(&transaction->list));
142 0 : WARN_ON(!RB_EMPTY_ROOT(
143 : &transaction->delayed_refs.href_root.rb_root));
144 0 : WARN_ON(!RB_EMPTY_ROOT(
145 : &transaction->delayed_refs.dirty_extent_root));
146 0 : if (transaction->delayed_refs.pending_csums)
147 0 : btrfs_err(transaction->fs_info,
148 : "pending csums is %llu",
149 : transaction->delayed_refs.pending_csums);
150 : /*
151 : * If any block groups are found in ->deleted_bgs then it's
152 : * because the transaction was aborted and a commit did not
153 : * happen (things failed before writing the new superblock
154 : * and calling btrfs_finish_extent_commit()), so we can not
155 : * discard the physical locations of the block groups.
156 : */
157 0 : while (!list_empty(&transaction->deleted_bgs)) {
158 0 : struct btrfs_block_group *cache;
159 :
160 0 : cache = list_first_entry(&transaction->deleted_bgs,
161 : struct btrfs_block_group,
162 : bg_list);
163 0 : list_del_init(&cache->bg_list);
164 0 : btrfs_unfreeze_block_group(cache);
165 0 : btrfs_put_block_group(cache);
166 : }
167 0 : WARN_ON(!list_empty(&transaction->dev_update_list));
168 0 : kfree(transaction);
169 : }
170 0 : }
171 :
172 0 : static noinline void switch_commit_roots(struct btrfs_trans_handle *trans)
173 : {
174 0 : struct btrfs_transaction *cur_trans = trans->transaction;
175 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
176 0 : struct btrfs_root *root, *tmp;
177 :
178 : /*
179 : * At this point no one can be using this transaction to modify any tree
180 : * and no one can start another transaction to modify any tree either.
181 : */
182 0 : ASSERT(cur_trans->state == TRANS_STATE_COMMIT_DOING);
183 :
184 0 : down_write(&fs_info->commit_root_sem);
185 :
186 0 : if (test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
187 0 : fs_info->last_reloc_trans = trans->transid;
188 :
189 0 : list_for_each_entry_safe(root, tmp, &cur_trans->switch_commits,
190 : dirty_list) {
191 0 : list_del_init(&root->dirty_list);
192 0 : free_extent_buffer(root->commit_root);
193 0 : root->commit_root = btrfs_root_node(root);
194 0 : extent_io_tree_release(&root->dirty_log_pages);
195 0 : btrfs_qgroup_clean_swapped_blocks(root);
196 : }
197 :
198 : /* We can free old roots now. */
199 0 : spin_lock(&cur_trans->dropped_roots_lock);
200 0 : while (!list_empty(&cur_trans->dropped_roots)) {
201 0 : root = list_first_entry(&cur_trans->dropped_roots,
202 : struct btrfs_root, root_list);
203 0 : list_del_init(&root->root_list);
204 0 : spin_unlock(&cur_trans->dropped_roots_lock);
205 0 : btrfs_free_log(trans, root);
206 0 : btrfs_drop_and_free_fs_root(fs_info, root);
207 0 : spin_lock(&cur_trans->dropped_roots_lock);
208 : }
209 0 : spin_unlock(&cur_trans->dropped_roots_lock);
210 :
211 0 : up_write(&fs_info->commit_root_sem);
212 0 : }
213 :
214 0 : static inline void extwriter_counter_inc(struct btrfs_transaction *trans,
215 : unsigned int type)
216 : {
217 0 : if (type & TRANS_EXTWRITERS)
218 0 : atomic_inc(&trans->num_extwriters);
219 0 : }
220 :
221 0 : static inline void extwriter_counter_dec(struct btrfs_transaction *trans,
222 : unsigned int type)
223 : {
224 0 : if (type & TRANS_EXTWRITERS)
225 0 : atomic_dec(&trans->num_extwriters);
226 0 : }
227 :
228 : static inline void extwriter_counter_init(struct btrfs_transaction *trans,
229 : unsigned int type)
230 : {
231 0 : atomic_set(&trans->num_extwriters, ((type & TRANS_EXTWRITERS) ? 1 : 0));
232 : }
233 :
234 : static inline int extwriter_counter_read(struct btrfs_transaction *trans)
235 : {
236 0 : return atomic_read(&trans->num_extwriters);
237 : }
238 :
239 : /*
240 : * To be called after doing the chunk btree updates right after allocating a new
241 : * chunk (after btrfs_chunk_alloc_add_chunk_item() is called), when removing a
242 : * chunk after all chunk btree updates and after finishing the second phase of
243 : * chunk allocation (btrfs_create_pending_block_groups()) in case some block
244 : * group had its chunk item insertion delayed to the second phase.
245 : */
246 0 : void btrfs_trans_release_chunk_metadata(struct btrfs_trans_handle *trans)
247 : {
248 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
249 :
250 0 : if (!trans->chunk_bytes_reserved)
251 : return;
252 :
253 0 : btrfs_block_rsv_release(fs_info, &fs_info->chunk_block_rsv,
254 : trans->chunk_bytes_reserved, NULL);
255 0 : trans->chunk_bytes_reserved = 0;
256 : }
257 :
258 : /*
259 : * either allocate a new transaction or hop into the existing one
260 : */
261 0 : static noinline int join_transaction(struct btrfs_fs_info *fs_info,
262 : unsigned int type)
263 : {
264 0 : struct btrfs_transaction *cur_trans;
265 :
266 0 : spin_lock(&fs_info->trans_lock);
267 0 : loop:
268 : /* The file system has been taken offline. No new transactions. */
269 0 : if (BTRFS_FS_ERROR(fs_info)) {
270 0 : spin_unlock(&fs_info->trans_lock);
271 0 : return -EROFS;
272 : }
273 :
274 0 : cur_trans = fs_info->running_transaction;
275 0 : if (cur_trans) {
276 0 : if (TRANS_ABORTED(cur_trans)) {
277 0 : spin_unlock(&fs_info->trans_lock);
278 0 : return cur_trans->aborted;
279 : }
280 0 : if (btrfs_blocked_trans_types[cur_trans->state] & type) {
281 0 : spin_unlock(&fs_info->trans_lock);
282 0 : return -EBUSY;
283 : }
284 0 : refcount_inc(&cur_trans->use_count);
285 0 : atomic_inc(&cur_trans->num_writers);
286 0 : extwriter_counter_inc(cur_trans, type);
287 0 : spin_unlock(&fs_info->trans_lock);
288 0 : btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
289 0 : btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
290 0 : return 0;
291 : }
292 0 : spin_unlock(&fs_info->trans_lock);
293 :
294 : /*
295 : * If we are ATTACH, we just want to catch the current transaction,
296 : * and commit it. If there is no transaction, just return ENOENT.
297 : */
298 0 : if (type == TRANS_ATTACH)
299 : return -ENOENT;
300 :
301 : /*
302 : * JOIN_NOLOCK only happens during the transaction commit, so
303 : * it is impossible that ->running_transaction is NULL
304 : */
305 0 : BUG_ON(type == TRANS_JOIN_NOLOCK);
306 :
307 0 : cur_trans = kmalloc(sizeof(*cur_trans), GFP_NOFS);
308 0 : if (!cur_trans)
309 : return -ENOMEM;
310 :
311 0 : btrfs_lockdep_acquire(fs_info, btrfs_trans_num_writers);
312 0 : btrfs_lockdep_acquire(fs_info, btrfs_trans_num_extwriters);
313 :
314 0 : spin_lock(&fs_info->trans_lock);
315 0 : if (fs_info->running_transaction) {
316 : /*
317 : * someone started a transaction after we unlocked. Make sure
318 : * to redo the checks above
319 : */
320 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
321 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
322 0 : kfree(cur_trans);
323 0 : goto loop;
324 0 : } else if (BTRFS_FS_ERROR(fs_info)) {
325 0 : spin_unlock(&fs_info->trans_lock);
326 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
327 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
328 0 : kfree(cur_trans);
329 0 : return -EROFS;
330 : }
331 :
332 0 : cur_trans->fs_info = fs_info;
333 0 : atomic_set(&cur_trans->pending_ordered, 0);
334 0 : init_waitqueue_head(&cur_trans->pending_wait);
335 0 : atomic_set(&cur_trans->num_writers, 1);
336 0 : extwriter_counter_init(cur_trans, type);
337 0 : init_waitqueue_head(&cur_trans->writer_wait);
338 0 : init_waitqueue_head(&cur_trans->commit_wait);
339 0 : cur_trans->state = TRANS_STATE_RUNNING;
340 : /*
341 : * One for this trans handle, one so it will live on until we
342 : * commit the transaction.
343 : */
344 0 : refcount_set(&cur_trans->use_count, 2);
345 0 : cur_trans->flags = 0;
346 0 : cur_trans->start_time = ktime_get_seconds();
347 :
348 0 : memset(&cur_trans->delayed_refs, 0, sizeof(cur_trans->delayed_refs));
349 :
350 0 : cur_trans->delayed_refs.href_root = RB_ROOT_CACHED;
351 0 : cur_trans->delayed_refs.dirty_extent_root = RB_ROOT;
352 0 : atomic_set(&cur_trans->delayed_refs.num_entries, 0);
353 :
354 : /*
355 : * although the tree mod log is per file system and not per transaction,
356 : * the log must never go across transaction boundaries.
357 : */
358 0 : smp_mb();
359 0 : if (!list_empty(&fs_info->tree_mod_seq_list))
360 0 : WARN(1, KERN_ERR "BTRFS: tree_mod_seq_list not empty when creating a fresh transaction\n");
361 0 : if (!RB_EMPTY_ROOT(&fs_info->tree_mod_log))
362 0 : WARN(1, KERN_ERR "BTRFS: tree_mod_log rb tree not empty when creating a fresh transaction\n");
363 0 : atomic64_set(&fs_info->tree_mod_seq, 0);
364 :
365 0 : spin_lock_init(&cur_trans->delayed_refs.lock);
366 :
367 0 : INIT_LIST_HEAD(&cur_trans->pending_snapshots);
368 0 : INIT_LIST_HEAD(&cur_trans->dev_update_list);
369 0 : INIT_LIST_HEAD(&cur_trans->switch_commits);
370 0 : INIT_LIST_HEAD(&cur_trans->dirty_bgs);
371 0 : INIT_LIST_HEAD(&cur_trans->io_bgs);
372 0 : INIT_LIST_HEAD(&cur_trans->dropped_roots);
373 0 : mutex_init(&cur_trans->cache_write_mutex);
374 0 : spin_lock_init(&cur_trans->dirty_bgs_lock);
375 0 : INIT_LIST_HEAD(&cur_trans->deleted_bgs);
376 0 : spin_lock_init(&cur_trans->dropped_roots_lock);
377 0 : list_add_tail(&cur_trans->list, &fs_info->trans_list);
378 0 : extent_io_tree_init(fs_info, &cur_trans->dirty_pages,
379 : IO_TREE_TRANS_DIRTY_PAGES);
380 0 : extent_io_tree_init(fs_info, &cur_trans->pinned_extents,
381 : IO_TREE_FS_PINNED_EXTENTS);
382 0 : fs_info->generation++;
383 0 : cur_trans->transid = fs_info->generation;
384 0 : fs_info->running_transaction = cur_trans;
385 0 : cur_trans->aborted = 0;
386 0 : spin_unlock(&fs_info->trans_lock);
387 :
388 0 : return 0;
389 : }
390 :
391 : /*
392 : * This does all the record keeping required to make sure that a shareable root
393 : * is properly recorded in a given transaction. This is required to make sure
394 : * the old root from before we joined the transaction is deleted when the
395 : * transaction commits.
396 : */
397 0 : static int record_root_in_trans(struct btrfs_trans_handle *trans,
398 : struct btrfs_root *root,
399 : int force)
400 : {
401 0 : struct btrfs_fs_info *fs_info = root->fs_info;
402 0 : int ret = 0;
403 :
404 0 : if ((test_bit(BTRFS_ROOT_SHAREABLE, &root->state) &&
405 0 : root->last_trans < trans->transid) || force) {
406 0 : WARN_ON(!force && root->commit_root != root->node);
407 :
408 : /*
409 : * see below for IN_TRANS_SETUP usage rules
410 : * we have the reloc mutex held now, so there
411 : * is only one writer in this function
412 : */
413 0 : set_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
414 :
415 : /* make sure readers find IN_TRANS_SETUP before
416 : * they find our root->last_trans update
417 : */
418 0 : smp_wmb();
419 :
420 0 : spin_lock(&fs_info->fs_roots_radix_lock);
421 0 : if (root->last_trans == trans->transid && !force) {
422 0 : spin_unlock(&fs_info->fs_roots_radix_lock);
423 0 : return 0;
424 : }
425 0 : radix_tree_tag_set(&fs_info->fs_roots_radix,
426 0 : (unsigned long)root->root_key.objectid,
427 : BTRFS_ROOT_TRANS_TAG);
428 0 : spin_unlock(&fs_info->fs_roots_radix_lock);
429 0 : root->last_trans = trans->transid;
430 :
431 : /* this is pretty tricky. We don't want to
432 : * take the relocation lock in btrfs_record_root_in_trans
433 : * unless we're really doing the first setup for this root in
434 : * this transaction.
435 : *
436 : * Normally we'd use root->last_trans as a flag to decide
437 : * if we want to take the expensive mutex.
438 : *
439 : * But, we have to set root->last_trans before we
440 : * init the relocation root, otherwise, we trip over warnings
441 : * in ctree.c. The solution used here is to flag ourselves
442 : * with root IN_TRANS_SETUP. When this is 1, we're still
443 : * fixing up the reloc trees and everyone must wait.
444 : *
445 : * When this is zero, they can trust root->last_trans and fly
446 : * through btrfs_record_root_in_trans without having to take the
447 : * lock. smp_wmb() makes sure that all the writes above are
448 : * done before we pop in the zero below
449 : */
450 0 : ret = btrfs_init_reloc_root(trans, root);
451 0 : smp_mb__before_atomic();
452 0 : clear_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state);
453 : }
454 : return ret;
455 : }
456 :
457 :
458 0 : void btrfs_add_dropped_root(struct btrfs_trans_handle *trans,
459 : struct btrfs_root *root)
460 : {
461 0 : struct btrfs_fs_info *fs_info = root->fs_info;
462 0 : struct btrfs_transaction *cur_trans = trans->transaction;
463 :
464 : /* Add ourselves to the transaction dropped list */
465 0 : spin_lock(&cur_trans->dropped_roots_lock);
466 0 : list_add_tail(&root->root_list, &cur_trans->dropped_roots);
467 0 : spin_unlock(&cur_trans->dropped_roots_lock);
468 :
469 : /* Make sure we don't try to update the root at commit time */
470 0 : spin_lock(&fs_info->fs_roots_radix_lock);
471 0 : radix_tree_tag_clear(&fs_info->fs_roots_radix,
472 0 : (unsigned long)root->root_key.objectid,
473 : BTRFS_ROOT_TRANS_TAG);
474 0 : spin_unlock(&fs_info->fs_roots_radix_lock);
475 0 : }
476 :
477 0 : int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
478 : struct btrfs_root *root)
479 : {
480 0 : struct btrfs_fs_info *fs_info = root->fs_info;
481 0 : int ret;
482 :
483 0 : if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
484 : return 0;
485 :
486 : /*
487 : * see record_root_in_trans for comments about IN_TRANS_SETUP usage
488 : * and barriers
489 : */
490 0 : smp_rmb();
491 0 : if (root->last_trans == trans->transid &&
492 0 : !test_bit(BTRFS_ROOT_IN_TRANS_SETUP, &root->state))
493 : return 0;
494 :
495 0 : mutex_lock(&fs_info->reloc_mutex);
496 0 : ret = record_root_in_trans(trans, root, 0);
497 0 : mutex_unlock(&fs_info->reloc_mutex);
498 :
499 0 : return ret;
500 : }
501 :
502 : static inline int is_transaction_blocked(struct btrfs_transaction *trans)
503 : {
504 0 : return (trans->state >= TRANS_STATE_COMMIT_START &&
505 0 : trans->state < TRANS_STATE_UNBLOCKED &&
506 0 : !TRANS_ABORTED(trans));
507 : }
508 :
509 : /* wait for commit against the current transaction to become unblocked
510 : * when this is done, it is safe to start a new transaction, but the current
511 : * transaction might not be fully on disk.
512 : */
513 0 : static void wait_current_trans(struct btrfs_fs_info *fs_info)
514 : {
515 0 : struct btrfs_transaction *cur_trans;
516 :
517 0 : spin_lock(&fs_info->trans_lock);
518 0 : cur_trans = fs_info->running_transaction;
519 0 : if (cur_trans && is_transaction_blocked(cur_trans)) {
520 0 : refcount_inc(&cur_trans->use_count);
521 0 : spin_unlock(&fs_info->trans_lock);
522 :
523 0 : btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
524 0 : wait_event(fs_info->transaction_wait,
525 : cur_trans->state >= TRANS_STATE_UNBLOCKED ||
526 : TRANS_ABORTED(cur_trans));
527 0 : btrfs_put_transaction(cur_trans);
528 : } else {
529 0 : spin_unlock(&fs_info->trans_lock);
530 : }
531 0 : }
532 :
533 0 : static int may_wait_transaction(struct btrfs_fs_info *fs_info, int type)
534 : {
535 0 : if (test_bit(BTRFS_FS_LOG_RECOVERING, &fs_info->flags))
536 : return 0;
537 :
538 0 : if (type == TRANS_START)
539 0 : return 1;
540 :
541 : return 0;
542 : }
543 :
544 0 : static inline bool need_reserve_reloc_root(struct btrfs_root *root)
545 : {
546 0 : struct btrfs_fs_info *fs_info = root->fs_info;
547 :
548 0 : if (!fs_info->reloc_ctl ||
549 0 : !test_bit(BTRFS_ROOT_SHAREABLE, &root->state) ||
550 0 : root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID ||
551 0 : root->reloc_root)
552 0 : return false;
553 :
554 : return true;
555 : }
556 :
557 : static struct btrfs_trans_handle *
558 0 : start_transaction(struct btrfs_root *root, unsigned int num_items,
559 : unsigned int type, enum btrfs_reserve_flush_enum flush,
560 : bool enforce_qgroups)
561 : {
562 0 : struct btrfs_fs_info *fs_info = root->fs_info;
563 0 : struct btrfs_block_rsv *delayed_refs_rsv = &fs_info->delayed_refs_rsv;
564 0 : struct btrfs_trans_handle *h;
565 0 : struct btrfs_transaction *cur_trans;
566 0 : u64 num_bytes = 0;
567 0 : u64 qgroup_reserved = 0;
568 0 : bool reloc_reserved = false;
569 0 : bool do_chunk_alloc = false;
570 0 : int ret;
571 :
572 0 : if (BTRFS_FS_ERROR(fs_info))
573 : return ERR_PTR(-EROFS);
574 :
575 0 : if (current->journal_info) {
576 0 : WARN_ON(type & TRANS_EXTWRITERS);
577 0 : h = current->journal_info;
578 0 : refcount_inc(&h->use_count);
579 0 : WARN_ON(refcount_read(&h->use_count) > 2);
580 0 : h->orig_rsv = h->block_rsv;
581 0 : h->block_rsv = NULL;
582 0 : goto got_it;
583 : }
584 :
585 : /*
586 : * Do the reservation before we join the transaction so we can do all
587 : * the appropriate flushing if need be.
588 : */
589 0 : if (num_items && root != fs_info->chunk_root) {
590 0 : struct btrfs_block_rsv *rsv = &fs_info->trans_block_rsv;
591 0 : u64 delayed_refs_bytes = 0;
592 :
593 0 : qgroup_reserved = num_items * fs_info->nodesize;
594 0 : ret = btrfs_qgroup_reserve_meta_pertrans(root, qgroup_reserved,
595 : enforce_qgroups);
596 0 : if (ret)
597 0 : return ERR_PTR(ret);
598 :
599 : /*
600 : * We want to reserve all the bytes we may need all at once, so
601 : * we only do 1 enospc flushing cycle per transaction start. We
602 : * accomplish this by simply assuming we'll do num_items worth
603 : * of delayed refs updates in this trans handle, and refill that
604 : * amount for whatever is missing in the reserve.
605 : */
606 0 : num_bytes = btrfs_calc_insert_metadata_size(fs_info, num_items);
607 0 : if (flush == BTRFS_RESERVE_FLUSH_ALL &&
608 : !btrfs_block_rsv_full(delayed_refs_rsv)) {
609 0 : delayed_refs_bytes = btrfs_calc_delayed_ref_bytes(fs_info,
610 : num_items);
611 0 : num_bytes += delayed_refs_bytes;
612 : }
613 :
614 : /*
615 : * Do the reservation for the relocation root creation
616 : */
617 0 : if (need_reserve_reloc_root(root)) {
618 0 : num_bytes += fs_info->nodesize;
619 0 : reloc_reserved = true;
620 : }
621 :
622 0 : ret = btrfs_block_rsv_add(fs_info, rsv, num_bytes, flush);
623 0 : if (ret)
624 0 : goto reserve_fail;
625 0 : if (delayed_refs_bytes) {
626 0 : btrfs_migrate_to_delayed_refs_rsv(fs_info, rsv,
627 : delayed_refs_bytes);
628 0 : num_bytes -= delayed_refs_bytes;
629 : }
630 :
631 0 : if (rsv->space_info->force_alloc)
632 0 : do_chunk_alloc = true;
633 0 : } else if (num_items == 0 && flush == BTRFS_RESERVE_FLUSH_ALL &&
634 : !btrfs_block_rsv_full(delayed_refs_rsv)) {
635 : /*
636 : * Some people call with btrfs_start_transaction(root, 0)
637 : * because they can be throttled, but have some other mechanism
638 : * for reserving space. We still want these guys to refill the
639 : * delayed block_rsv so just add 1 items worth of reservation
640 : * here.
641 : */
642 0 : ret = btrfs_delayed_refs_rsv_refill(fs_info, flush);
643 0 : if (ret)
644 0 : goto reserve_fail;
645 : }
646 0 : again:
647 0 : h = kmem_cache_zalloc(btrfs_trans_handle_cachep, GFP_NOFS);
648 0 : if (!h) {
649 0 : ret = -ENOMEM;
650 0 : goto alloc_fail;
651 : }
652 :
653 : /*
654 : * If we are JOIN_NOLOCK we're already committing a transaction and
655 : * waiting on this guy, so we don't need to do the sb_start_intwrite
656 : * because we're already holding a ref. We need this because we could
657 : * have raced in and did an fsync() on a file which can kick a commit
658 : * and then we deadlock with somebody doing a freeze.
659 : *
660 : * If we are ATTACH, it means we just want to catch the current
661 : * transaction and commit it, so we needn't do sb_start_intwrite().
662 : */
663 0 : if (type & __TRANS_FREEZABLE)
664 0 : sb_start_intwrite(fs_info->sb);
665 :
666 0 : if (may_wait_transaction(fs_info, type))
667 0 : wait_current_trans(fs_info);
668 :
669 0 : do {
670 0 : ret = join_transaction(fs_info, type);
671 0 : if (ret == -EBUSY) {
672 0 : wait_current_trans(fs_info);
673 0 : if (unlikely(type == TRANS_ATTACH ||
674 : type == TRANS_JOIN_NOSTART))
675 : ret = -ENOENT;
676 : }
677 0 : } while (ret == -EBUSY);
678 :
679 0 : if (ret < 0)
680 0 : goto join_fail;
681 :
682 0 : cur_trans = fs_info->running_transaction;
683 :
684 0 : h->transid = cur_trans->transid;
685 0 : h->transaction = cur_trans;
686 0 : refcount_set(&h->use_count, 1);
687 0 : h->fs_info = root->fs_info;
688 :
689 0 : h->type = type;
690 0 : INIT_LIST_HEAD(&h->new_bgs);
691 :
692 0 : smp_mb();
693 0 : if (cur_trans->state >= TRANS_STATE_COMMIT_START &&
694 0 : may_wait_transaction(fs_info, type)) {
695 0 : current->journal_info = h;
696 0 : btrfs_commit_transaction(h);
697 0 : goto again;
698 : }
699 :
700 0 : if (num_bytes) {
701 0 : trace_btrfs_space_reservation(fs_info, "transaction",
702 : h->transid, num_bytes, 1);
703 0 : h->block_rsv = &fs_info->trans_block_rsv;
704 0 : h->bytes_reserved = num_bytes;
705 0 : h->reloc_reserved = reloc_reserved;
706 : }
707 :
708 0 : got_it:
709 0 : if (!current->journal_info)
710 0 : current->journal_info = h;
711 :
712 : /*
713 : * If the space_info is marked ALLOC_FORCE then we'll get upgraded to
714 : * ALLOC_FORCE the first run through, and then we won't allocate for
715 : * anybody else who races in later. We don't care about the return
716 : * value here.
717 : */
718 0 : if (do_chunk_alloc && num_bytes) {
719 0 : u64 flags = h->block_rsv->space_info->flags;
720 :
721 0 : btrfs_chunk_alloc(h, btrfs_get_alloc_profile(fs_info, flags),
722 : CHUNK_ALLOC_NO_FORCE);
723 : }
724 :
725 : /*
726 : * btrfs_record_root_in_trans() needs to alloc new extents, and may
727 : * call btrfs_join_transaction() while we're also starting a
728 : * transaction.
729 : *
730 : * Thus it need to be called after current->journal_info initialized,
731 : * or we can deadlock.
732 : */
733 0 : ret = btrfs_record_root_in_trans(h, root);
734 0 : if (ret) {
735 : /*
736 : * The transaction handle is fully initialized and linked with
737 : * other structures so it needs to be ended in case of errors,
738 : * not just freed.
739 : */
740 0 : btrfs_end_transaction(h);
741 0 : return ERR_PTR(ret);
742 : }
743 :
744 : return h;
745 :
746 : join_fail:
747 0 : if (type & __TRANS_FREEZABLE)
748 0 : sb_end_intwrite(fs_info->sb);
749 0 : kmem_cache_free(btrfs_trans_handle_cachep, h);
750 0 : alloc_fail:
751 0 : if (num_bytes)
752 0 : btrfs_block_rsv_release(fs_info, &fs_info->trans_block_rsv,
753 : num_bytes, NULL);
754 0 : reserve_fail:
755 0 : btrfs_qgroup_free_meta_pertrans(root, qgroup_reserved);
756 0 : return ERR_PTR(ret);
757 : }
758 :
759 0 : struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
760 : unsigned int num_items)
761 : {
762 0 : return start_transaction(root, num_items, TRANS_START,
763 : BTRFS_RESERVE_FLUSH_ALL, true);
764 : }
765 :
766 0 : struct btrfs_trans_handle *btrfs_start_transaction_fallback_global_rsv(
767 : struct btrfs_root *root,
768 : unsigned int num_items)
769 : {
770 0 : return start_transaction(root, num_items, TRANS_START,
771 : BTRFS_RESERVE_FLUSH_ALL_STEAL, false);
772 : }
773 :
774 0 : struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
775 : {
776 0 : return start_transaction(root, 0, TRANS_JOIN, BTRFS_RESERVE_NO_FLUSH,
777 : true);
778 : }
779 :
780 0 : struct btrfs_trans_handle *btrfs_join_transaction_spacecache(struct btrfs_root *root)
781 : {
782 0 : return start_transaction(root, 0, TRANS_JOIN_NOLOCK,
783 : BTRFS_RESERVE_NO_FLUSH, true);
784 : }
785 :
786 : /*
787 : * Similar to regular join but it never starts a transaction when none is
788 : * running or after waiting for the current one to finish.
789 : */
790 0 : struct btrfs_trans_handle *btrfs_join_transaction_nostart(struct btrfs_root *root)
791 : {
792 0 : return start_transaction(root, 0, TRANS_JOIN_NOSTART,
793 : BTRFS_RESERVE_NO_FLUSH, true);
794 : }
795 :
796 : /*
797 : * btrfs_attach_transaction() - catch the running transaction
798 : *
799 : * It is used when we want to commit the current the transaction, but
800 : * don't want to start a new one.
801 : *
802 : * Note: If this function return -ENOENT, it just means there is no
803 : * running transaction. But it is possible that the inactive transaction
804 : * is still in the memory, not fully on disk. If you hope there is no
805 : * inactive transaction in the fs when -ENOENT is returned, you should
806 : * invoke
807 : * btrfs_attach_transaction_barrier()
808 : */
809 0 : struct btrfs_trans_handle *btrfs_attach_transaction(struct btrfs_root *root)
810 : {
811 0 : return start_transaction(root, 0, TRANS_ATTACH,
812 : BTRFS_RESERVE_NO_FLUSH, true);
813 : }
814 :
815 : /*
816 : * btrfs_attach_transaction_barrier() - catch the running transaction
817 : *
818 : * It is similar to the above function, the difference is this one
819 : * will wait for all the inactive transactions until they fully
820 : * complete.
821 : */
822 : struct btrfs_trans_handle *
823 0 : btrfs_attach_transaction_barrier(struct btrfs_root *root)
824 : {
825 0 : struct btrfs_trans_handle *trans;
826 :
827 0 : trans = start_transaction(root, 0, TRANS_ATTACH,
828 : BTRFS_RESERVE_NO_FLUSH, true);
829 0 : if (trans == ERR_PTR(-ENOENT)) {
830 0 : int ret;
831 :
832 0 : ret = btrfs_wait_for_commit(root->fs_info, 0);
833 0 : if (ret)
834 0 : return ERR_PTR(ret);
835 : }
836 :
837 : return trans;
838 : }
839 :
840 : /* Wait for a transaction commit to reach at least the given state. */
841 0 : static noinline void wait_for_commit(struct btrfs_transaction *commit,
842 : const enum btrfs_trans_state min_state)
843 : {
844 0 : struct btrfs_fs_info *fs_info = commit->fs_info;
845 0 : u64 transid = commit->transid;
846 0 : bool put = false;
847 :
848 : /*
849 : * At the moment this function is called with min_state either being
850 : * TRANS_STATE_COMPLETED or TRANS_STATE_SUPER_COMMITTED.
851 : */
852 0 : if (min_state == TRANS_STATE_COMPLETED)
853 : btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
854 : else
855 0 : btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
856 :
857 0 : while (1) {
858 0 : wait_event(commit->commit_wait, commit->state >= min_state);
859 0 : if (put)
860 0 : btrfs_put_transaction(commit);
861 :
862 0 : if (min_state < TRANS_STATE_COMPLETED)
863 : break;
864 :
865 : /*
866 : * A transaction isn't really completed until all of the
867 : * previous transactions are completed, but with fsync we can
868 : * end up with SUPER_COMMITTED transactions before a COMPLETED
869 : * transaction. Wait for those.
870 : */
871 :
872 0 : spin_lock(&fs_info->trans_lock);
873 0 : commit = list_first_entry_or_null(&fs_info->trans_list,
874 : struct btrfs_transaction,
875 : list);
876 0 : if (!commit || commit->transid > transid) {
877 0 : spin_unlock(&fs_info->trans_lock);
878 : break;
879 : }
880 0 : refcount_inc(&commit->use_count);
881 0 : put = true;
882 0 : spin_unlock(&fs_info->trans_lock);
883 : }
884 0 : }
885 :
886 0 : int btrfs_wait_for_commit(struct btrfs_fs_info *fs_info, u64 transid)
887 : {
888 0 : struct btrfs_transaction *cur_trans = NULL, *t;
889 0 : int ret = 0;
890 :
891 0 : if (transid) {
892 0 : if (transid <= fs_info->last_trans_committed)
893 0 : goto out;
894 :
895 : /* find specified transaction */
896 0 : spin_lock(&fs_info->trans_lock);
897 0 : list_for_each_entry(t, &fs_info->trans_list, list) {
898 0 : if (t->transid == transid) {
899 0 : cur_trans = t;
900 0 : refcount_inc(&cur_trans->use_count);
901 0 : ret = 0;
902 0 : break;
903 : }
904 0 : if (t->transid > transid) {
905 : ret = 0;
906 : break;
907 : }
908 : }
909 0 : spin_unlock(&fs_info->trans_lock);
910 :
911 : /*
912 : * The specified transaction doesn't exist, or we
913 : * raced with btrfs_commit_transaction
914 : */
915 0 : if (!cur_trans) {
916 0 : if (transid > fs_info->last_trans_committed)
917 0 : ret = -EINVAL;
918 0 : goto out;
919 : }
920 : } else {
921 : /* find newest transaction that is committing | committed */
922 0 : spin_lock(&fs_info->trans_lock);
923 0 : list_for_each_entry_reverse(t, &fs_info->trans_list,
924 : list) {
925 0 : if (t->state >= TRANS_STATE_COMMIT_START) {
926 0 : if (t->state == TRANS_STATE_COMPLETED)
927 : break;
928 0 : cur_trans = t;
929 0 : refcount_inc(&cur_trans->use_count);
930 : break;
931 : }
932 : }
933 0 : spin_unlock(&fs_info->trans_lock);
934 0 : if (!cur_trans)
935 0 : goto out; /* nothing committing|committed */
936 : }
937 :
938 0 : wait_for_commit(cur_trans, TRANS_STATE_COMPLETED);
939 0 : ret = cur_trans->aborted;
940 0 : btrfs_put_transaction(cur_trans);
941 0 : out:
942 0 : return ret;
943 : }
944 :
945 0 : void btrfs_throttle(struct btrfs_fs_info *fs_info)
946 : {
947 0 : wait_current_trans(fs_info);
948 0 : }
949 :
950 0 : bool btrfs_should_end_transaction(struct btrfs_trans_handle *trans)
951 : {
952 0 : struct btrfs_transaction *cur_trans = trans->transaction;
953 :
954 0 : if (cur_trans->state >= TRANS_STATE_COMMIT_START ||
955 0 : test_bit(BTRFS_DELAYED_REFS_FLUSHING, &cur_trans->delayed_refs.flags))
956 : return true;
957 :
958 0 : if (btrfs_check_space_for_delayed_refs(trans->fs_info))
959 : return true;
960 :
961 0 : return !!btrfs_block_rsv_check(&trans->fs_info->global_block_rsv, 50);
962 : }
963 :
964 0 : static void btrfs_trans_release_metadata(struct btrfs_trans_handle *trans)
965 :
966 : {
967 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
968 :
969 0 : if (!trans->block_rsv) {
970 : ASSERT(!trans->bytes_reserved);
971 : return;
972 : }
973 :
974 0 : if (!trans->bytes_reserved)
975 : return;
976 :
977 0 : ASSERT(trans->block_rsv == &fs_info->trans_block_rsv);
978 0 : trace_btrfs_space_reservation(fs_info, "transaction",
979 : trans->transid, trans->bytes_reserved, 0);
980 0 : btrfs_block_rsv_release(fs_info, trans->block_rsv,
981 : trans->bytes_reserved, NULL);
982 0 : trans->bytes_reserved = 0;
983 : }
984 :
985 0 : static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
986 : int throttle)
987 : {
988 0 : struct btrfs_fs_info *info = trans->fs_info;
989 0 : struct btrfs_transaction *cur_trans = trans->transaction;
990 0 : int err = 0;
991 :
992 0 : if (refcount_read(&trans->use_count) > 1) {
993 0 : refcount_dec(&trans->use_count);
994 0 : trans->block_rsv = trans->orig_rsv;
995 0 : return 0;
996 : }
997 :
998 0 : btrfs_trans_release_metadata(trans);
999 0 : trans->block_rsv = NULL;
1000 :
1001 0 : btrfs_create_pending_block_groups(trans);
1002 :
1003 0 : btrfs_trans_release_chunk_metadata(trans);
1004 :
1005 0 : if (trans->type & __TRANS_FREEZABLE)
1006 0 : sb_end_intwrite(info->sb);
1007 :
1008 0 : WARN_ON(cur_trans != info->running_transaction);
1009 0 : WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
1010 0 : atomic_dec(&cur_trans->num_writers);
1011 0 : extwriter_counter_dec(cur_trans, trans->type);
1012 :
1013 0 : cond_wake_up(&cur_trans->writer_wait);
1014 :
1015 0 : btrfs_lockdep_release(info, btrfs_trans_num_extwriters);
1016 0 : btrfs_lockdep_release(info, btrfs_trans_num_writers);
1017 :
1018 0 : btrfs_put_transaction(cur_trans);
1019 :
1020 0 : if (current->journal_info == trans)
1021 0 : current->journal_info = NULL;
1022 :
1023 0 : if (throttle)
1024 0 : btrfs_run_delayed_iputs(info);
1025 :
1026 0 : if (TRANS_ABORTED(trans) || BTRFS_FS_ERROR(info)) {
1027 0 : wake_up_process(info->transaction_kthread);
1028 0 : if (TRANS_ABORTED(trans))
1029 0 : err = trans->aborted;
1030 : else
1031 : err = -EROFS;
1032 : }
1033 :
1034 0 : kmem_cache_free(btrfs_trans_handle_cachep, trans);
1035 0 : return err;
1036 : }
1037 :
1038 0 : int btrfs_end_transaction(struct btrfs_trans_handle *trans)
1039 : {
1040 0 : return __btrfs_end_transaction(trans, 0);
1041 : }
1042 :
1043 0 : int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans)
1044 : {
1045 0 : return __btrfs_end_transaction(trans, 1);
1046 : }
1047 :
1048 : /*
1049 : * when btree blocks are allocated, they have some corresponding bits set for
1050 : * them in one of two extent_io trees. This is used to make sure all of
1051 : * those extents are sent to disk but does not wait on them
1052 : */
1053 0 : int btrfs_write_marked_extents(struct btrfs_fs_info *fs_info,
1054 : struct extent_io_tree *dirty_pages, int mark)
1055 : {
1056 0 : int err = 0;
1057 0 : int werr = 0;
1058 0 : struct address_space *mapping = fs_info->btree_inode->i_mapping;
1059 0 : struct extent_state *cached_state = NULL;
1060 0 : u64 start = 0;
1061 0 : u64 end;
1062 :
1063 0 : while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1064 : mark, &cached_state)) {
1065 0 : bool wait_writeback = false;
1066 :
1067 0 : err = convert_extent_bit(dirty_pages, start, end,
1068 : EXTENT_NEED_WAIT,
1069 : mark, &cached_state);
1070 : /*
1071 : * convert_extent_bit can return -ENOMEM, which is most of the
1072 : * time a temporary error. So when it happens, ignore the error
1073 : * and wait for writeback of this range to finish - because we
1074 : * failed to set the bit EXTENT_NEED_WAIT for the range, a call
1075 : * to __btrfs_wait_marked_extents() would not know that
1076 : * writeback for this range started and therefore wouldn't
1077 : * wait for it to finish - we don't want to commit a
1078 : * superblock that points to btree nodes/leafs for which
1079 : * writeback hasn't finished yet (and without errors).
1080 : * We cleanup any entries left in the io tree when committing
1081 : * the transaction (through extent_io_tree_release()).
1082 : */
1083 0 : if (err == -ENOMEM) {
1084 : err = 0;
1085 : wait_writeback = true;
1086 : }
1087 0 : if (!err)
1088 0 : err = filemap_fdatawrite_range(mapping, start, end);
1089 0 : if (err)
1090 : werr = err;
1091 0 : else if (wait_writeback)
1092 0 : werr = filemap_fdatawait_range(mapping, start, end);
1093 0 : free_extent_state(cached_state);
1094 0 : cached_state = NULL;
1095 0 : cond_resched();
1096 0 : start = end + 1;
1097 : }
1098 0 : return werr;
1099 : }
1100 :
1101 : /*
1102 : * when btree blocks are allocated, they have some corresponding bits set for
1103 : * them in one of two extent_io trees. This is used to make sure all of
1104 : * those extents are on disk for transaction or log commit. We wait
1105 : * on all the pages and clear them from the dirty pages state tree
1106 : */
1107 0 : static int __btrfs_wait_marked_extents(struct btrfs_fs_info *fs_info,
1108 : struct extent_io_tree *dirty_pages)
1109 : {
1110 0 : int err = 0;
1111 0 : int werr = 0;
1112 0 : struct address_space *mapping = fs_info->btree_inode->i_mapping;
1113 0 : struct extent_state *cached_state = NULL;
1114 0 : u64 start = 0;
1115 0 : u64 end;
1116 :
1117 0 : while (!find_first_extent_bit(dirty_pages, start, &start, &end,
1118 : EXTENT_NEED_WAIT, &cached_state)) {
1119 : /*
1120 : * Ignore -ENOMEM errors returned by clear_extent_bit().
1121 : * When committing the transaction, we'll remove any entries
1122 : * left in the io tree. For a log commit, we don't remove them
1123 : * after committing the log because the tree can be accessed
1124 : * concurrently - we do it only at transaction commit time when
1125 : * it's safe to do it (through extent_io_tree_release()).
1126 : */
1127 0 : err = clear_extent_bit(dirty_pages, start, end,
1128 : EXTENT_NEED_WAIT, &cached_state);
1129 0 : if (err == -ENOMEM)
1130 : err = 0;
1131 0 : if (!err)
1132 0 : err = filemap_fdatawait_range(mapping, start, end);
1133 0 : if (err)
1134 0 : werr = err;
1135 0 : free_extent_state(cached_state);
1136 0 : cached_state = NULL;
1137 0 : cond_resched();
1138 0 : start = end + 1;
1139 : }
1140 0 : if (err)
1141 0 : werr = err;
1142 0 : return werr;
1143 : }
1144 :
1145 0 : static int btrfs_wait_extents(struct btrfs_fs_info *fs_info,
1146 : struct extent_io_tree *dirty_pages)
1147 : {
1148 0 : bool errors = false;
1149 0 : int err;
1150 :
1151 0 : err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1152 0 : if (test_and_clear_bit(BTRFS_FS_BTREE_ERR, &fs_info->flags))
1153 0 : errors = true;
1154 :
1155 0 : if (errors && !err)
1156 0 : err = -EIO;
1157 0 : return err;
1158 : }
1159 :
1160 0 : int btrfs_wait_tree_log_extents(struct btrfs_root *log_root, int mark)
1161 : {
1162 0 : struct btrfs_fs_info *fs_info = log_root->fs_info;
1163 0 : struct extent_io_tree *dirty_pages = &log_root->dirty_log_pages;
1164 0 : bool errors = false;
1165 0 : int err;
1166 :
1167 0 : ASSERT(log_root->root_key.objectid == BTRFS_TREE_LOG_OBJECTID);
1168 :
1169 0 : err = __btrfs_wait_marked_extents(fs_info, dirty_pages);
1170 0 : if ((mark & EXTENT_DIRTY) &&
1171 0 : test_and_clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags))
1172 0 : errors = true;
1173 :
1174 0 : if ((mark & EXTENT_NEW) &&
1175 0 : test_and_clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags))
1176 0 : errors = true;
1177 :
1178 0 : if (errors && !err)
1179 0 : err = -EIO;
1180 0 : return err;
1181 : }
1182 :
1183 : /*
1184 : * When btree blocks are allocated the corresponding extents are marked dirty.
1185 : * This function ensures such extents are persisted on disk for transaction or
1186 : * log commit.
1187 : *
1188 : * @trans: transaction whose dirty pages we'd like to write
1189 : */
1190 0 : static int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans)
1191 : {
1192 0 : int ret;
1193 0 : int ret2;
1194 0 : struct extent_io_tree *dirty_pages = &trans->transaction->dirty_pages;
1195 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1196 0 : struct blk_plug plug;
1197 :
1198 0 : blk_start_plug(&plug);
1199 0 : ret = btrfs_write_marked_extents(fs_info, dirty_pages, EXTENT_DIRTY);
1200 0 : blk_finish_plug(&plug);
1201 0 : ret2 = btrfs_wait_extents(fs_info, dirty_pages);
1202 :
1203 0 : extent_io_tree_release(&trans->transaction->dirty_pages);
1204 :
1205 0 : if (ret)
1206 : return ret;
1207 0 : else if (ret2)
1208 : return ret2;
1209 : else
1210 0 : return 0;
1211 : }
1212 :
1213 : /*
1214 : * this is used to update the root pointer in the tree of tree roots.
1215 : *
1216 : * But, in the case of the extent allocation tree, updating the root
1217 : * pointer may allocate blocks which may change the root of the extent
1218 : * allocation tree.
1219 : *
1220 : * So, this loops and repeats and makes sure the cowonly root didn't
1221 : * change while the root pointer was being updated in the metadata.
1222 : */
1223 0 : static int update_cowonly_root(struct btrfs_trans_handle *trans,
1224 : struct btrfs_root *root)
1225 : {
1226 0 : int ret;
1227 0 : u64 old_root_bytenr;
1228 0 : u64 old_root_used;
1229 0 : struct btrfs_fs_info *fs_info = root->fs_info;
1230 0 : struct btrfs_root *tree_root = fs_info->tree_root;
1231 :
1232 0 : old_root_used = btrfs_root_used(&root->root_item);
1233 :
1234 0 : while (1) {
1235 0 : old_root_bytenr = btrfs_root_bytenr(&root->root_item);
1236 0 : if (old_root_bytenr == root->node->start &&
1237 : old_root_used == btrfs_root_used(&root->root_item))
1238 : break;
1239 :
1240 0 : btrfs_set_root_node(&root->root_item, root->node);
1241 0 : ret = btrfs_update_root(trans, tree_root,
1242 : &root->root_key,
1243 : &root->root_item);
1244 0 : if (ret)
1245 0 : return ret;
1246 :
1247 0 : old_root_used = btrfs_root_used(&root->root_item);
1248 : }
1249 :
1250 : return 0;
1251 : }
1252 :
1253 : /*
1254 : * update all the cowonly tree roots on disk
1255 : *
1256 : * The error handling in this function may not be obvious. Any of the
1257 : * failures will cause the file system to go offline. We still need
1258 : * to clean up the delayed refs.
1259 : */
1260 0 : static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans)
1261 : {
1262 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1263 0 : struct list_head *dirty_bgs = &trans->transaction->dirty_bgs;
1264 0 : struct list_head *io_bgs = &trans->transaction->io_bgs;
1265 0 : struct list_head *next;
1266 0 : struct extent_buffer *eb;
1267 0 : int ret;
1268 :
1269 : /*
1270 : * At this point no one can be using this transaction to modify any tree
1271 : * and no one can start another transaction to modify any tree either.
1272 : */
1273 0 : ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1274 :
1275 0 : eb = btrfs_lock_root_node(fs_info->tree_root);
1276 0 : ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
1277 : 0, &eb, BTRFS_NESTING_COW);
1278 0 : btrfs_tree_unlock(eb);
1279 0 : free_extent_buffer(eb);
1280 :
1281 0 : if (ret)
1282 : return ret;
1283 :
1284 0 : ret = btrfs_run_dev_stats(trans);
1285 0 : if (ret)
1286 : return ret;
1287 0 : ret = btrfs_run_dev_replace(trans);
1288 0 : if (ret)
1289 : return ret;
1290 0 : ret = btrfs_run_qgroups(trans);
1291 0 : if (ret)
1292 : return ret;
1293 :
1294 0 : ret = btrfs_setup_space_cache(trans);
1295 0 : if (ret)
1296 : return ret;
1297 :
1298 0 : again:
1299 0 : while (!list_empty(&fs_info->dirty_cowonly_roots)) {
1300 0 : struct btrfs_root *root;
1301 0 : next = fs_info->dirty_cowonly_roots.next;
1302 0 : list_del_init(next);
1303 0 : root = list_entry(next, struct btrfs_root, dirty_list);
1304 0 : clear_bit(BTRFS_ROOT_DIRTY, &root->state);
1305 :
1306 0 : list_add_tail(&root->dirty_list,
1307 0 : &trans->transaction->switch_commits);
1308 0 : ret = update_cowonly_root(trans, root);
1309 0 : if (ret)
1310 0 : return ret;
1311 : }
1312 :
1313 : /* Now flush any delayed refs generated by updating all of the roots */
1314 0 : ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1315 0 : if (ret)
1316 0 : return ret;
1317 :
1318 0 : while (!list_empty(dirty_bgs) || !list_empty(io_bgs)) {
1319 0 : ret = btrfs_write_dirty_block_groups(trans);
1320 0 : if (ret)
1321 0 : return ret;
1322 :
1323 : /*
1324 : * We're writing the dirty block groups, which could generate
1325 : * delayed refs, which could generate more dirty block groups,
1326 : * so we want to keep this flushing in this loop to make sure
1327 : * everything gets run.
1328 : */
1329 0 : ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1330 0 : if (ret)
1331 0 : return ret;
1332 : }
1333 :
1334 0 : if (!list_empty(&fs_info->dirty_cowonly_roots))
1335 0 : goto again;
1336 :
1337 : /* Update dev-replace pointer once everything is committed */
1338 0 : fs_info->dev_replace.committed_cursor_left =
1339 0 : fs_info->dev_replace.cursor_left_last_write_of_item;
1340 :
1341 0 : return 0;
1342 : }
1343 :
1344 : /*
1345 : * If we had a pending drop we need to see if there are any others left in our
1346 : * dead roots list, and if not clear our bit and wake any waiters.
1347 : */
1348 0 : void btrfs_maybe_wake_unfinished_drop(struct btrfs_fs_info *fs_info)
1349 : {
1350 : /*
1351 : * We put the drop in progress roots at the front of the list, so if the
1352 : * first entry doesn't have UNFINISHED_DROP set we can wake everybody
1353 : * up.
1354 : */
1355 0 : spin_lock(&fs_info->trans_lock);
1356 0 : if (!list_empty(&fs_info->dead_roots)) {
1357 0 : struct btrfs_root *root = list_first_entry(&fs_info->dead_roots,
1358 : struct btrfs_root,
1359 : root_list);
1360 0 : if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state)) {
1361 0 : spin_unlock(&fs_info->trans_lock);
1362 0 : return;
1363 : }
1364 : }
1365 0 : spin_unlock(&fs_info->trans_lock);
1366 :
1367 0 : btrfs_wake_unfinished_drop(fs_info);
1368 : }
1369 :
1370 : /*
1371 : * dead roots are old snapshots that need to be deleted. This allocates
1372 : * a dirty root struct and adds it into the list of dead roots that need to
1373 : * be deleted
1374 : */
1375 0 : void btrfs_add_dead_root(struct btrfs_root *root)
1376 : {
1377 0 : struct btrfs_fs_info *fs_info = root->fs_info;
1378 :
1379 0 : spin_lock(&fs_info->trans_lock);
1380 0 : if (list_empty(&root->root_list)) {
1381 0 : btrfs_grab_root(root);
1382 :
1383 : /* We want to process the partially complete drops first. */
1384 0 : if (test_bit(BTRFS_ROOT_UNFINISHED_DROP, &root->state))
1385 0 : list_add(&root->root_list, &fs_info->dead_roots);
1386 : else
1387 0 : list_add_tail(&root->root_list, &fs_info->dead_roots);
1388 : }
1389 0 : spin_unlock(&fs_info->trans_lock);
1390 0 : }
1391 :
1392 : /*
1393 : * Update each subvolume root and its relocation root, if it exists, in the tree
1394 : * of tree roots. Also free log roots if they exist.
1395 : */
1396 0 : static noinline int commit_fs_roots(struct btrfs_trans_handle *trans)
1397 : {
1398 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1399 0 : struct btrfs_root *gang[8];
1400 0 : int i;
1401 0 : int ret;
1402 :
1403 : /*
1404 : * At this point no one can be using this transaction to modify any tree
1405 : * and no one can start another transaction to modify any tree either.
1406 : */
1407 0 : ASSERT(trans->transaction->state == TRANS_STATE_COMMIT_DOING);
1408 :
1409 0 : spin_lock(&fs_info->fs_roots_radix_lock);
1410 0 : while (1) {
1411 0 : ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
1412 : (void **)gang, 0,
1413 : ARRAY_SIZE(gang),
1414 : BTRFS_ROOT_TRANS_TAG);
1415 0 : if (ret == 0)
1416 : break;
1417 0 : for (i = 0; i < ret; i++) {
1418 0 : struct btrfs_root *root = gang[i];
1419 0 : int ret2;
1420 :
1421 : /*
1422 : * At this point we can neither have tasks logging inodes
1423 : * from a root nor trying to commit a log tree.
1424 : */
1425 0 : ASSERT(atomic_read(&root->log_writers) == 0);
1426 0 : ASSERT(atomic_read(&root->log_commit[0]) == 0);
1427 0 : ASSERT(atomic_read(&root->log_commit[1]) == 0);
1428 :
1429 0 : radix_tree_tag_clear(&fs_info->fs_roots_radix,
1430 0 : (unsigned long)root->root_key.objectid,
1431 : BTRFS_ROOT_TRANS_TAG);
1432 0 : spin_unlock(&fs_info->fs_roots_radix_lock);
1433 :
1434 0 : btrfs_free_log(trans, root);
1435 0 : ret2 = btrfs_update_reloc_root(trans, root);
1436 0 : if (ret2)
1437 0 : return ret2;
1438 :
1439 : /* see comments in should_cow_block() */
1440 0 : clear_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1441 0 : smp_mb__after_atomic();
1442 :
1443 0 : if (root->commit_root != root->node) {
1444 0 : list_add_tail(&root->dirty_list,
1445 0 : &trans->transaction->switch_commits);
1446 0 : btrfs_set_root_node(&root->root_item,
1447 : root->node);
1448 : }
1449 :
1450 0 : ret2 = btrfs_update_root(trans, fs_info->tree_root,
1451 : &root->root_key,
1452 : &root->root_item);
1453 0 : if (ret2)
1454 0 : return ret2;
1455 0 : spin_lock(&fs_info->fs_roots_radix_lock);
1456 0 : btrfs_qgroup_free_meta_all_pertrans(root);
1457 : }
1458 : }
1459 0 : spin_unlock(&fs_info->fs_roots_radix_lock);
1460 0 : return 0;
1461 : }
1462 :
1463 : /*
1464 : * defrag a given btree.
1465 : * Every leaf in the btree is read and defragged.
1466 : */
1467 0 : int btrfs_defrag_root(struct btrfs_root *root)
1468 : {
1469 0 : struct btrfs_fs_info *info = root->fs_info;
1470 0 : struct btrfs_trans_handle *trans;
1471 0 : int ret;
1472 :
1473 0 : if (test_and_set_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state))
1474 : return 0;
1475 :
1476 0 : while (1) {
1477 0 : trans = btrfs_start_transaction(root, 0);
1478 0 : if (IS_ERR(trans)) {
1479 0 : ret = PTR_ERR(trans);
1480 0 : break;
1481 : }
1482 :
1483 0 : ret = btrfs_defrag_leaves(trans, root);
1484 :
1485 0 : btrfs_end_transaction(trans);
1486 0 : btrfs_btree_balance_dirty(info);
1487 0 : cond_resched();
1488 :
1489 0 : if (btrfs_fs_closing(info) || ret != -EAGAIN)
1490 : break;
1491 :
1492 0 : if (btrfs_defrag_cancelled(info)) {
1493 : btrfs_debug(info, "defrag_root cancelled");
1494 : ret = -EAGAIN;
1495 : break;
1496 : }
1497 : }
1498 0 : clear_bit(BTRFS_ROOT_DEFRAG_RUNNING, &root->state);
1499 : return ret;
1500 : }
1501 :
1502 : /*
1503 : * Do all special snapshot related qgroup dirty hack.
1504 : *
1505 : * Will do all needed qgroup inherit and dirty hack like switch commit
1506 : * roots inside one transaction and write all btree into disk, to make
1507 : * qgroup works.
1508 : */
1509 0 : static int qgroup_account_snapshot(struct btrfs_trans_handle *trans,
1510 : struct btrfs_root *src,
1511 : struct btrfs_root *parent,
1512 : struct btrfs_qgroup_inherit *inherit,
1513 : u64 dst_objectid)
1514 : {
1515 0 : struct btrfs_fs_info *fs_info = src->fs_info;
1516 0 : int ret;
1517 :
1518 : /*
1519 : * Save some performance in the case that qgroups are not
1520 : * enabled. If this check races with the ioctl, rescan will
1521 : * kick in anyway.
1522 : */
1523 0 : if (!test_bit(BTRFS_FS_QUOTA_ENABLED, &fs_info->flags))
1524 : return 0;
1525 :
1526 : /*
1527 : * Ensure dirty @src will be committed. Or, after coming
1528 : * commit_fs_roots() and switch_commit_roots(), any dirty but not
1529 : * recorded root will never be updated again, causing an outdated root
1530 : * item.
1531 : */
1532 0 : ret = record_root_in_trans(trans, src, 1);
1533 0 : if (ret)
1534 : return ret;
1535 :
1536 : /*
1537 : * btrfs_qgroup_inherit relies on a consistent view of the usage for the
1538 : * src root, so we must run the delayed refs here.
1539 : *
1540 : * However this isn't particularly fool proof, because there's no
1541 : * synchronization keeping us from changing the tree after this point
1542 : * before we do the qgroup_inherit, or even from making changes while
1543 : * we're doing the qgroup_inherit. But that's a problem for the future,
1544 : * for now flush the delayed refs to narrow the race window where the
1545 : * qgroup counters could end up wrong.
1546 : */
1547 0 : ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
1548 0 : if (ret) {
1549 0 : btrfs_abort_transaction(trans, ret);
1550 0 : return ret;
1551 : }
1552 :
1553 0 : ret = commit_fs_roots(trans);
1554 0 : if (ret)
1555 0 : goto out;
1556 0 : ret = btrfs_qgroup_account_extents(trans);
1557 0 : if (ret < 0)
1558 0 : goto out;
1559 :
1560 : /* Now qgroup are all updated, we can inherit it to new qgroups */
1561 0 : ret = btrfs_qgroup_inherit(trans, src->root_key.objectid, dst_objectid,
1562 : inherit);
1563 0 : if (ret < 0)
1564 0 : goto out;
1565 :
1566 : /*
1567 : * Now we do a simplified commit transaction, which will:
1568 : * 1) commit all subvolume and extent tree
1569 : * To ensure all subvolume and extent tree have a valid
1570 : * commit_root to accounting later insert_dir_item()
1571 : * 2) write all btree blocks onto disk
1572 : * This is to make sure later btree modification will be cowed
1573 : * Or commit_root can be populated and cause wrong qgroup numbers
1574 : * In this simplified commit, we don't really care about other trees
1575 : * like chunk and root tree, as they won't affect qgroup.
1576 : * And we don't write super to avoid half committed status.
1577 : */
1578 0 : ret = commit_cowonly_roots(trans);
1579 0 : if (ret)
1580 0 : goto out;
1581 0 : switch_commit_roots(trans);
1582 0 : ret = btrfs_write_and_wait_transaction(trans);
1583 0 : if (ret)
1584 0 : btrfs_handle_fs_error(fs_info, ret,
1585 : "Error while writing out transaction for qgroup");
1586 :
1587 0 : out:
1588 : /*
1589 : * Force parent root to be updated, as we recorded it before so its
1590 : * last_trans == cur_transid.
1591 : * Or it won't be committed again onto disk after later
1592 : * insert_dir_item()
1593 : */
1594 0 : if (!ret)
1595 0 : ret = record_root_in_trans(trans, parent, 1);
1596 : return ret;
1597 : }
1598 :
1599 : /*
1600 : * new snapshots need to be created at a very specific time in the
1601 : * transaction commit. This does the actual creation.
1602 : *
1603 : * Note:
1604 : * If the error which may affect the commitment of the current transaction
1605 : * happens, we should return the error number. If the error which just affect
1606 : * the creation of the pending snapshots, just return 0.
1607 : */
1608 0 : static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
1609 : struct btrfs_pending_snapshot *pending)
1610 : {
1611 :
1612 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1613 0 : struct btrfs_key key;
1614 0 : struct btrfs_root_item *new_root_item;
1615 0 : struct btrfs_root *tree_root = fs_info->tree_root;
1616 0 : struct btrfs_root *root = pending->root;
1617 0 : struct btrfs_root *parent_root;
1618 0 : struct btrfs_block_rsv *rsv;
1619 0 : struct inode *parent_inode = pending->dir;
1620 0 : struct btrfs_path *path;
1621 0 : struct btrfs_dir_item *dir_item;
1622 0 : struct extent_buffer *tmp;
1623 0 : struct extent_buffer *old;
1624 0 : struct timespec64 cur_time;
1625 0 : int ret = 0;
1626 0 : u64 to_reserve = 0;
1627 0 : u64 index = 0;
1628 0 : u64 objectid;
1629 0 : u64 root_flags;
1630 0 : unsigned int nofs_flags;
1631 0 : struct fscrypt_name fname;
1632 :
1633 0 : ASSERT(pending->path);
1634 0 : path = pending->path;
1635 :
1636 0 : ASSERT(pending->root_item);
1637 0 : new_root_item = pending->root_item;
1638 :
1639 : /*
1640 : * We're inside a transaction and must make sure that any potential
1641 : * allocations with GFP_KERNEL in fscrypt won't recurse back to
1642 : * filesystem.
1643 : */
1644 0 : nofs_flags = memalloc_nofs_save();
1645 0 : pending->error = fscrypt_setup_filename(parent_inode,
1646 0 : &pending->dentry->d_name, 0,
1647 : &fname);
1648 0 : memalloc_nofs_restore(nofs_flags);
1649 0 : if (pending->error)
1650 0 : goto free_pending;
1651 :
1652 0 : pending->error = btrfs_get_free_objectid(tree_root, &objectid);
1653 0 : if (pending->error)
1654 0 : goto free_fname;
1655 :
1656 : /*
1657 : * Make qgroup to skip current new snapshot's qgroupid, as it is
1658 : * accounted by later btrfs_qgroup_inherit().
1659 : */
1660 0 : btrfs_set_skip_qgroup(trans, objectid);
1661 :
1662 0 : btrfs_reloc_pre_snapshot(pending, &to_reserve);
1663 :
1664 0 : if (to_reserve > 0) {
1665 0 : pending->error = btrfs_block_rsv_add(fs_info,
1666 : &pending->block_rsv,
1667 : to_reserve,
1668 : BTRFS_RESERVE_NO_FLUSH);
1669 0 : if (pending->error)
1670 0 : goto clear_skip_qgroup;
1671 : }
1672 :
1673 0 : key.objectid = objectid;
1674 0 : key.offset = (u64)-1;
1675 0 : key.type = BTRFS_ROOT_ITEM_KEY;
1676 :
1677 0 : rsv = trans->block_rsv;
1678 0 : trans->block_rsv = &pending->block_rsv;
1679 0 : trans->bytes_reserved = trans->block_rsv->reserved;
1680 0 : trace_btrfs_space_reservation(fs_info, "transaction",
1681 : trans->transid,
1682 : trans->bytes_reserved, 1);
1683 0 : parent_root = BTRFS_I(parent_inode)->root;
1684 0 : ret = record_root_in_trans(trans, parent_root, 0);
1685 0 : if (ret)
1686 0 : goto fail;
1687 0 : cur_time = current_time(parent_inode);
1688 :
1689 : /*
1690 : * insert the directory item
1691 : */
1692 0 : ret = btrfs_set_inode_index(BTRFS_I(parent_inode), &index);
1693 0 : if (ret) {
1694 0 : btrfs_abort_transaction(trans, ret);
1695 0 : goto fail;
1696 : }
1697 :
1698 : /* check if there is a file/dir which has the same name. */
1699 0 : dir_item = btrfs_lookup_dir_item(NULL, parent_root, path,
1700 : btrfs_ino(BTRFS_I(parent_inode)),
1701 : &fname.disk_name, 0);
1702 0 : if (dir_item != NULL && !IS_ERR(dir_item)) {
1703 0 : pending->error = -EEXIST;
1704 0 : goto dir_item_existed;
1705 0 : } else if (IS_ERR(dir_item)) {
1706 0 : ret = PTR_ERR(dir_item);
1707 0 : btrfs_abort_transaction(trans, ret);
1708 0 : goto fail;
1709 : }
1710 0 : btrfs_release_path(path);
1711 :
1712 : /*
1713 : * pull in the delayed directory update
1714 : * and the delayed inode item
1715 : * otherwise we corrupt the FS during
1716 : * snapshot
1717 : */
1718 0 : ret = btrfs_run_delayed_items(trans);
1719 0 : if (ret) { /* Transaction aborted */
1720 0 : btrfs_abort_transaction(trans, ret);
1721 0 : goto fail;
1722 : }
1723 :
1724 0 : ret = record_root_in_trans(trans, root, 0);
1725 0 : if (ret) {
1726 0 : btrfs_abort_transaction(trans, ret);
1727 0 : goto fail;
1728 : }
1729 0 : btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
1730 0 : memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
1731 0 : btrfs_check_and_init_root_item(new_root_item);
1732 :
1733 0 : root_flags = btrfs_root_flags(new_root_item);
1734 0 : if (pending->readonly)
1735 0 : root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
1736 : else
1737 0 : root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
1738 0 : btrfs_set_root_flags(new_root_item, root_flags);
1739 :
1740 0 : btrfs_set_root_generation_v2(new_root_item,
1741 : trans->transid);
1742 0 : generate_random_guid(new_root_item->uuid);
1743 0 : memcpy(new_root_item->parent_uuid, root->root_item.uuid,
1744 : BTRFS_UUID_SIZE);
1745 0 : if (!(root_flags & BTRFS_ROOT_SUBVOL_RDONLY)) {
1746 0 : memset(new_root_item->received_uuid, 0,
1747 : sizeof(new_root_item->received_uuid));
1748 0 : memset(&new_root_item->stime, 0, sizeof(new_root_item->stime));
1749 0 : memset(&new_root_item->rtime, 0, sizeof(new_root_item->rtime));
1750 0 : btrfs_set_root_stransid(new_root_item, 0);
1751 0 : btrfs_set_root_rtransid(new_root_item, 0);
1752 : }
1753 0 : btrfs_set_stack_timespec_sec(&new_root_item->otime, cur_time.tv_sec);
1754 0 : btrfs_set_stack_timespec_nsec(&new_root_item->otime, cur_time.tv_nsec);
1755 0 : btrfs_set_root_otransid(new_root_item, trans->transid);
1756 :
1757 0 : old = btrfs_lock_root_node(root);
1758 0 : ret = btrfs_cow_block(trans, root, old, NULL, 0, &old,
1759 : BTRFS_NESTING_COW);
1760 0 : if (ret) {
1761 0 : btrfs_tree_unlock(old);
1762 0 : free_extent_buffer(old);
1763 0 : btrfs_abort_transaction(trans, ret);
1764 0 : goto fail;
1765 : }
1766 :
1767 0 : ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1768 : /* clean up in any case */
1769 0 : btrfs_tree_unlock(old);
1770 0 : free_extent_buffer(old);
1771 0 : if (ret) {
1772 0 : btrfs_abort_transaction(trans, ret);
1773 0 : goto fail;
1774 : }
1775 : /* see comments in should_cow_block() */
1776 0 : set_bit(BTRFS_ROOT_FORCE_COW, &root->state);
1777 0 : smp_wmb();
1778 :
1779 0 : btrfs_set_root_node(new_root_item, tmp);
1780 : /* record when the snapshot was created in key.offset */
1781 0 : key.offset = trans->transid;
1782 0 : ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1783 0 : btrfs_tree_unlock(tmp);
1784 0 : free_extent_buffer(tmp);
1785 0 : if (ret) {
1786 0 : btrfs_abort_transaction(trans, ret);
1787 0 : goto fail;
1788 : }
1789 :
1790 : /*
1791 : * insert root back/forward references
1792 : */
1793 0 : ret = btrfs_add_root_ref(trans, objectid,
1794 : parent_root->root_key.objectid,
1795 : btrfs_ino(BTRFS_I(parent_inode)), index,
1796 : &fname.disk_name);
1797 0 : if (ret) {
1798 0 : btrfs_abort_transaction(trans, ret);
1799 0 : goto fail;
1800 : }
1801 :
1802 0 : key.offset = (u64)-1;
1803 0 : pending->snap = btrfs_get_new_fs_root(fs_info, objectid, pending->anon_dev);
1804 0 : if (IS_ERR(pending->snap)) {
1805 0 : ret = PTR_ERR(pending->snap);
1806 0 : pending->snap = NULL;
1807 0 : btrfs_abort_transaction(trans, ret);
1808 0 : goto fail;
1809 : }
1810 :
1811 0 : ret = btrfs_reloc_post_snapshot(trans, pending);
1812 0 : if (ret) {
1813 0 : btrfs_abort_transaction(trans, ret);
1814 0 : goto fail;
1815 : }
1816 :
1817 : /*
1818 : * Do special qgroup accounting for snapshot, as we do some qgroup
1819 : * snapshot hack to do fast snapshot.
1820 : * To co-operate with that hack, we do hack again.
1821 : * Or snapshot will be greatly slowed down by a subtree qgroup rescan
1822 : */
1823 0 : ret = qgroup_account_snapshot(trans, root, parent_root,
1824 : pending->inherit, objectid);
1825 0 : if (ret < 0)
1826 0 : goto fail;
1827 :
1828 0 : ret = btrfs_insert_dir_item(trans, &fname.disk_name,
1829 : BTRFS_I(parent_inode), &key, BTRFS_FT_DIR,
1830 : index);
1831 : /* We have check then name at the beginning, so it is impossible. */
1832 0 : BUG_ON(ret == -EEXIST || ret == -EOVERFLOW);
1833 0 : if (ret) {
1834 0 : btrfs_abort_transaction(trans, ret);
1835 0 : goto fail;
1836 : }
1837 :
1838 0 : btrfs_i_size_write(BTRFS_I(parent_inode), parent_inode->i_size +
1839 0 : fname.disk_name.len * 2);
1840 0 : parent_inode->i_mtime = current_time(parent_inode);
1841 0 : parent_inode->i_ctime = parent_inode->i_mtime;
1842 0 : ret = btrfs_update_inode_fallback(trans, parent_root, BTRFS_I(parent_inode));
1843 0 : if (ret) {
1844 0 : btrfs_abort_transaction(trans, ret);
1845 0 : goto fail;
1846 : }
1847 0 : ret = btrfs_uuid_tree_add(trans, new_root_item->uuid,
1848 : BTRFS_UUID_KEY_SUBVOL,
1849 : objectid);
1850 0 : if (ret) {
1851 0 : btrfs_abort_transaction(trans, ret);
1852 0 : goto fail;
1853 : }
1854 0 : if (!btrfs_is_empty_uuid(new_root_item->received_uuid)) {
1855 0 : ret = btrfs_uuid_tree_add(trans, new_root_item->received_uuid,
1856 : BTRFS_UUID_KEY_RECEIVED_SUBVOL,
1857 : objectid);
1858 0 : if (ret && ret != -EEXIST) {
1859 0 : btrfs_abort_transaction(trans, ret);
1860 0 : goto fail;
1861 : }
1862 : }
1863 :
1864 0 : fail:
1865 0 : pending->error = ret;
1866 0 : dir_item_existed:
1867 0 : trans->block_rsv = rsv;
1868 0 : trans->bytes_reserved = 0;
1869 0 : clear_skip_qgroup:
1870 0 : btrfs_clear_skip_qgroup(trans);
1871 : free_fname:
1872 : fscrypt_free_filename(&fname);
1873 0 : free_pending:
1874 0 : kfree(new_root_item);
1875 0 : pending->root_item = NULL;
1876 0 : btrfs_free_path(path);
1877 0 : pending->path = NULL;
1878 :
1879 0 : return ret;
1880 : }
1881 :
1882 : /*
1883 : * create all the snapshots we've scheduled for creation
1884 : */
1885 0 : static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans)
1886 : {
1887 0 : struct btrfs_pending_snapshot *pending, *next;
1888 0 : struct list_head *head = &trans->transaction->pending_snapshots;
1889 0 : int ret = 0;
1890 :
1891 0 : list_for_each_entry_safe(pending, next, head, list) {
1892 0 : list_del(&pending->list);
1893 0 : ret = create_pending_snapshot(trans, pending);
1894 0 : if (ret)
1895 : break;
1896 : }
1897 0 : return ret;
1898 : }
1899 :
1900 0 : static void update_super_roots(struct btrfs_fs_info *fs_info)
1901 : {
1902 0 : struct btrfs_root_item *root_item;
1903 0 : struct btrfs_super_block *super;
1904 :
1905 0 : super = fs_info->super_copy;
1906 :
1907 0 : root_item = &fs_info->chunk_root->root_item;
1908 0 : super->chunk_root = root_item->bytenr;
1909 0 : super->chunk_root_generation = root_item->generation;
1910 0 : super->chunk_root_level = root_item->level;
1911 :
1912 0 : root_item = &fs_info->tree_root->root_item;
1913 0 : super->root = root_item->bytenr;
1914 0 : super->generation = root_item->generation;
1915 0 : super->root_level = root_item->level;
1916 0 : if (btrfs_test_opt(fs_info, SPACE_CACHE))
1917 0 : super->cache_generation = root_item->generation;
1918 0 : else if (test_bit(BTRFS_FS_CLEANUP_SPACE_CACHE_V1, &fs_info->flags))
1919 0 : super->cache_generation = 0;
1920 0 : if (test_bit(BTRFS_FS_UPDATE_UUID_TREE_GEN, &fs_info->flags))
1921 0 : super->uuid_tree_generation = root_item->generation;
1922 0 : }
1923 :
1924 0 : int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1925 : {
1926 0 : struct btrfs_transaction *trans;
1927 0 : int ret = 0;
1928 :
1929 0 : spin_lock(&info->trans_lock);
1930 0 : trans = info->running_transaction;
1931 0 : if (trans)
1932 0 : ret = (trans->state >= TRANS_STATE_COMMIT_START);
1933 0 : spin_unlock(&info->trans_lock);
1934 0 : return ret;
1935 : }
1936 :
1937 0 : int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1938 : {
1939 0 : struct btrfs_transaction *trans;
1940 0 : int ret = 0;
1941 :
1942 0 : spin_lock(&info->trans_lock);
1943 0 : trans = info->running_transaction;
1944 0 : if (trans)
1945 0 : ret = is_transaction_blocked(trans);
1946 0 : spin_unlock(&info->trans_lock);
1947 0 : return ret;
1948 : }
1949 :
1950 0 : void btrfs_commit_transaction_async(struct btrfs_trans_handle *trans)
1951 : {
1952 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1953 0 : struct btrfs_transaction *cur_trans;
1954 :
1955 : /* Kick the transaction kthread. */
1956 0 : set_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
1957 0 : wake_up_process(fs_info->transaction_kthread);
1958 :
1959 : /* take transaction reference */
1960 0 : cur_trans = trans->transaction;
1961 0 : refcount_inc(&cur_trans->use_count);
1962 :
1963 0 : btrfs_end_transaction(trans);
1964 :
1965 : /*
1966 : * Wait for the current transaction commit to start and block
1967 : * subsequent transaction joins
1968 : */
1969 0 : btrfs_might_wait_for_state(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
1970 0 : wait_event(fs_info->transaction_blocked_wait,
1971 : cur_trans->state >= TRANS_STATE_COMMIT_START ||
1972 : TRANS_ABORTED(cur_trans));
1973 0 : btrfs_put_transaction(cur_trans);
1974 0 : }
1975 :
1976 0 : static void cleanup_transaction(struct btrfs_trans_handle *trans, int err)
1977 : {
1978 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
1979 0 : struct btrfs_transaction *cur_trans = trans->transaction;
1980 :
1981 0 : WARN_ON(refcount_read(&trans->use_count) > 1);
1982 :
1983 0 : btrfs_abort_transaction(trans, err);
1984 :
1985 0 : spin_lock(&fs_info->trans_lock);
1986 :
1987 : /*
1988 : * If the transaction is removed from the list, it means this
1989 : * transaction has been committed successfully, so it is impossible
1990 : * to call the cleanup function.
1991 : */
1992 0 : BUG_ON(list_empty(&cur_trans->list));
1993 :
1994 0 : if (cur_trans == fs_info->running_transaction) {
1995 0 : cur_trans->state = TRANS_STATE_COMMIT_DOING;
1996 0 : spin_unlock(&fs_info->trans_lock);
1997 :
1998 : /*
1999 : * The thread has already released the lockdep map as reader
2000 : * already in btrfs_commit_transaction().
2001 : */
2002 0 : btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2003 0 : wait_event(cur_trans->writer_wait,
2004 : atomic_read(&cur_trans->num_writers) == 1);
2005 :
2006 0 : spin_lock(&fs_info->trans_lock);
2007 : }
2008 :
2009 : /*
2010 : * Now that we know no one else is still using the transaction we can
2011 : * remove the transaction from the list of transactions. This avoids
2012 : * the transaction kthread from cleaning up the transaction while some
2013 : * other task is still using it, which could result in a use-after-free
2014 : * on things like log trees, as it forces the transaction kthread to
2015 : * wait for this transaction to be cleaned up by us.
2016 : */
2017 0 : list_del_init(&cur_trans->list);
2018 :
2019 0 : spin_unlock(&fs_info->trans_lock);
2020 :
2021 0 : btrfs_cleanup_one_transaction(trans->transaction, fs_info);
2022 :
2023 0 : spin_lock(&fs_info->trans_lock);
2024 0 : if (cur_trans == fs_info->running_transaction)
2025 0 : fs_info->running_transaction = NULL;
2026 0 : spin_unlock(&fs_info->trans_lock);
2027 :
2028 0 : if (trans->type & __TRANS_FREEZABLE)
2029 0 : sb_end_intwrite(fs_info->sb);
2030 0 : btrfs_put_transaction(cur_trans);
2031 0 : btrfs_put_transaction(cur_trans);
2032 :
2033 0 : trace_btrfs_transaction_commit(fs_info);
2034 :
2035 0 : if (current->journal_info == trans)
2036 0 : current->journal_info = NULL;
2037 :
2038 : /*
2039 : * If relocation is running, we can't cancel scrub because that will
2040 : * result in a deadlock. Before relocating a block group, relocation
2041 : * pauses scrub, then starts and commits a transaction before unpausing
2042 : * scrub. If the transaction commit is being done by the relocation
2043 : * task or triggered by another task and the relocation task is waiting
2044 : * for the commit, and we end up here due to an error in the commit
2045 : * path, then calling btrfs_scrub_cancel() will deadlock, as we are
2046 : * asking for scrub to stop while having it asked to be paused higher
2047 : * above in relocation code.
2048 : */
2049 0 : if (!test_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags))
2050 0 : btrfs_scrub_cancel(fs_info);
2051 :
2052 0 : kmem_cache_free(btrfs_trans_handle_cachep, trans);
2053 0 : }
2054 :
2055 : /*
2056 : * Release reserved delayed ref space of all pending block groups of the
2057 : * transaction and remove them from the list
2058 : */
2059 0 : static void btrfs_cleanup_pending_block_groups(struct btrfs_trans_handle *trans)
2060 : {
2061 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
2062 0 : struct btrfs_block_group *block_group, *tmp;
2063 :
2064 0 : list_for_each_entry_safe(block_group, tmp, &trans->new_bgs, bg_list) {
2065 0 : btrfs_delayed_refs_rsv_release(fs_info, 1);
2066 0 : list_del_init(&block_group->bg_list);
2067 : }
2068 0 : }
2069 :
2070 0 : static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info)
2071 : {
2072 : /*
2073 : * We use try_to_writeback_inodes_sb() here because if we used
2074 : * btrfs_start_delalloc_roots we would deadlock with fs freeze.
2075 : * Currently are holding the fs freeze lock, if we do an async flush
2076 : * we'll do btrfs_join_transaction() and deadlock because we need to
2077 : * wait for the fs freeze lock. Using the direct flushing we benefit
2078 : * from already being in a transaction and our join_transaction doesn't
2079 : * have to re-take the fs freeze lock.
2080 : *
2081 : * Note that try_to_writeback_inodes_sb() will only trigger writeback
2082 : * if it can read lock sb->s_umount. It will always be able to lock it,
2083 : * except when the filesystem is being unmounted or being frozen, but in
2084 : * those cases sync_filesystem() is called, which results in calling
2085 : * writeback_inodes_sb() while holding a write lock on sb->s_umount.
2086 : * Note that we don't call writeback_inodes_sb() directly, because it
2087 : * will emit a warning if sb->s_umount is not locked.
2088 : */
2089 0 : if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2090 0 : try_to_writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC);
2091 0 : return 0;
2092 : }
2093 :
2094 0 : static inline void btrfs_wait_delalloc_flush(struct btrfs_fs_info *fs_info)
2095 : {
2096 0 : if (btrfs_test_opt(fs_info, FLUSHONCOMMIT))
2097 0 : btrfs_wait_ordered_roots(fs_info, U64_MAX, 0, (u64)-1);
2098 0 : }
2099 :
2100 : /*
2101 : * Add a pending snapshot associated with the given transaction handle to the
2102 : * respective handle. This must be called after the transaction commit started
2103 : * and while holding fs_info->trans_lock.
2104 : * This serves to guarantee a caller of btrfs_commit_transaction() that it can
2105 : * safely free the pending snapshot pointer in case btrfs_commit_transaction()
2106 : * returns an error.
2107 : */
2108 0 : static void add_pending_snapshot(struct btrfs_trans_handle *trans)
2109 : {
2110 0 : struct btrfs_transaction *cur_trans = trans->transaction;
2111 :
2112 0 : if (!trans->pending_snapshot)
2113 : return;
2114 :
2115 0 : lockdep_assert_held(&trans->fs_info->trans_lock);
2116 0 : ASSERT(cur_trans->state >= TRANS_STATE_COMMIT_START);
2117 :
2118 0 : list_add(&trans->pending_snapshot->list, &cur_trans->pending_snapshots);
2119 : }
2120 :
2121 : static void update_commit_stats(struct btrfs_fs_info *fs_info, ktime_t interval)
2122 : {
2123 0 : fs_info->commit_stats.commit_count++;
2124 0 : fs_info->commit_stats.last_commit_dur = interval;
2125 0 : fs_info->commit_stats.max_commit_dur =
2126 0 : max_t(u64, fs_info->commit_stats.max_commit_dur, interval);
2127 0 : fs_info->commit_stats.total_commit_dur += interval;
2128 : }
2129 :
2130 0 : int btrfs_commit_transaction(struct btrfs_trans_handle *trans)
2131 : {
2132 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
2133 0 : struct btrfs_transaction *cur_trans = trans->transaction;
2134 0 : struct btrfs_transaction *prev_trans = NULL;
2135 0 : int ret;
2136 0 : ktime_t start_time;
2137 0 : ktime_t interval;
2138 :
2139 0 : ASSERT(refcount_read(&trans->use_count) == 1);
2140 0 : btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2141 :
2142 0 : clear_bit(BTRFS_FS_NEED_TRANS_COMMIT, &fs_info->flags);
2143 :
2144 : /* Stop the commit early if ->aborted is set */
2145 0 : if (TRANS_ABORTED(cur_trans)) {
2146 0 : ret = cur_trans->aborted;
2147 0 : goto lockdep_trans_commit_start_release;
2148 : }
2149 :
2150 0 : btrfs_trans_release_metadata(trans);
2151 0 : trans->block_rsv = NULL;
2152 :
2153 : /*
2154 : * We only want one transaction commit doing the flushing so we do not
2155 : * waste a bunch of time on lock contention on the extent root node.
2156 : */
2157 0 : if (!test_and_set_bit(BTRFS_DELAYED_REFS_FLUSHING,
2158 0 : &cur_trans->delayed_refs.flags)) {
2159 : /*
2160 : * Make a pass through all the delayed refs we have so far.
2161 : * Any running threads may add more while we are here.
2162 : */
2163 0 : ret = btrfs_run_delayed_refs(trans, 0);
2164 0 : if (ret)
2165 0 : goto lockdep_trans_commit_start_release;
2166 : }
2167 :
2168 0 : btrfs_create_pending_block_groups(trans);
2169 :
2170 0 : if (!test_bit(BTRFS_TRANS_DIRTY_BG_RUN, &cur_trans->flags)) {
2171 0 : int run_it = 0;
2172 :
2173 : /* this mutex is also taken before trying to set
2174 : * block groups readonly. We need to make sure
2175 : * that nobody has set a block group readonly
2176 : * after a extents from that block group have been
2177 : * allocated for cache files. btrfs_set_block_group_ro
2178 : * will wait for the transaction to commit if it
2179 : * finds BTRFS_TRANS_DIRTY_BG_RUN set.
2180 : *
2181 : * The BTRFS_TRANS_DIRTY_BG_RUN flag is also used to make sure
2182 : * only one process starts all the block group IO. It wouldn't
2183 : * hurt to have more than one go through, but there's no
2184 : * real advantage to it either.
2185 : */
2186 0 : mutex_lock(&fs_info->ro_block_group_mutex);
2187 0 : if (!test_and_set_bit(BTRFS_TRANS_DIRTY_BG_RUN,
2188 : &cur_trans->flags))
2189 0 : run_it = 1;
2190 0 : mutex_unlock(&fs_info->ro_block_group_mutex);
2191 :
2192 0 : if (run_it) {
2193 0 : ret = btrfs_start_dirty_block_groups(trans);
2194 0 : if (ret)
2195 0 : goto lockdep_trans_commit_start_release;
2196 : }
2197 : }
2198 :
2199 0 : spin_lock(&fs_info->trans_lock);
2200 0 : if (cur_trans->state >= TRANS_STATE_COMMIT_START) {
2201 0 : enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2202 :
2203 0 : add_pending_snapshot(trans);
2204 :
2205 0 : spin_unlock(&fs_info->trans_lock);
2206 0 : refcount_inc(&cur_trans->use_count);
2207 :
2208 0 : if (trans->in_fsync)
2209 0 : want_state = TRANS_STATE_SUPER_COMMITTED;
2210 :
2211 0 : btrfs_trans_state_lockdep_release(fs_info,
2212 : BTRFS_LOCKDEP_TRANS_COMMIT_START);
2213 0 : ret = btrfs_end_transaction(trans);
2214 0 : wait_for_commit(cur_trans, want_state);
2215 :
2216 0 : if (TRANS_ABORTED(cur_trans))
2217 0 : ret = cur_trans->aborted;
2218 :
2219 0 : btrfs_put_transaction(cur_trans);
2220 :
2221 0 : return ret;
2222 : }
2223 :
2224 0 : cur_trans->state = TRANS_STATE_COMMIT_START;
2225 0 : wake_up(&fs_info->transaction_blocked_wait);
2226 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2227 :
2228 0 : if (cur_trans->list.prev != &fs_info->trans_list) {
2229 0 : enum btrfs_trans_state want_state = TRANS_STATE_COMPLETED;
2230 :
2231 0 : if (trans->in_fsync)
2232 0 : want_state = TRANS_STATE_SUPER_COMMITTED;
2233 :
2234 0 : prev_trans = list_entry(cur_trans->list.prev,
2235 : struct btrfs_transaction, list);
2236 0 : if (prev_trans->state < want_state) {
2237 0 : refcount_inc(&prev_trans->use_count);
2238 0 : spin_unlock(&fs_info->trans_lock);
2239 :
2240 0 : wait_for_commit(prev_trans, want_state);
2241 :
2242 0 : ret = READ_ONCE(prev_trans->aborted);
2243 :
2244 0 : btrfs_put_transaction(prev_trans);
2245 0 : if (ret)
2246 0 : goto lockdep_release;
2247 : } else {
2248 0 : spin_unlock(&fs_info->trans_lock);
2249 : }
2250 : } else {
2251 0 : spin_unlock(&fs_info->trans_lock);
2252 : /*
2253 : * The previous transaction was aborted and was already removed
2254 : * from the list of transactions at fs_info->trans_list. So we
2255 : * abort to prevent writing a new superblock that reflects a
2256 : * corrupt state (pointing to trees with unwritten nodes/leafs).
2257 : */
2258 0 : if (BTRFS_FS_ERROR(fs_info)) {
2259 0 : ret = -EROFS;
2260 0 : goto lockdep_release;
2261 : }
2262 : }
2263 :
2264 : /*
2265 : * Get the time spent on the work done by the commit thread and not
2266 : * the time spent waiting on a previous commit
2267 : */
2268 0 : start_time = ktime_get_ns();
2269 :
2270 0 : extwriter_counter_dec(cur_trans, trans->type);
2271 :
2272 0 : ret = btrfs_start_delalloc_flush(fs_info);
2273 0 : if (ret)
2274 0 : goto lockdep_release;
2275 :
2276 0 : ret = btrfs_run_delayed_items(trans);
2277 0 : if (ret)
2278 0 : goto lockdep_release;
2279 :
2280 : /*
2281 : * The thread has started/joined the transaction thus it holds the
2282 : * lockdep map as a reader. It has to release it before acquiring the
2283 : * lockdep map as a writer.
2284 : */
2285 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2286 0 : btrfs_might_wait_for_event(fs_info, btrfs_trans_num_extwriters);
2287 0 : wait_event(cur_trans->writer_wait,
2288 : extwriter_counter_read(cur_trans) == 0);
2289 :
2290 : /* some pending stuffs might be added after the previous flush. */
2291 0 : ret = btrfs_run_delayed_items(trans);
2292 0 : if (ret) {
2293 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2294 0 : goto cleanup_transaction;
2295 : }
2296 :
2297 0 : btrfs_wait_delalloc_flush(fs_info);
2298 :
2299 : /*
2300 : * Wait for all ordered extents started by a fast fsync that joined this
2301 : * transaction. Otherwise if this transaction commits before the ordered
2302 : * extents complete we lose logged data after a power failure.
2303 : */
2304 0 : btrfs_might_wait_for_event(fs_info, btrfs_trans_pending_ordered);
2305 0 : wait_event(cur_trans->pending_wait,
2306 : atomic_read(&cur_trans->pending_ordered) == 0);
2307 :
2308 0 : btrfs_scrub_pause(fs_info);
2309 : /*
2310 : * Ok now we need to make sure to block out any other joins while we
2311 : * commit the transaction. We could have started a join before setting
2312 : * COMMIT_DOING so make sure to wait for num_writers to == 1 again.
2313 : */
2314 0 : spin_lock(&fs_info->trans_lock);
2315 0 : add_pending_snapshot(trans);
2316 0 : cur_trans->state = TRANS_STATE_COMMIT_DOING;
2317 0 : spin_unlock(&fs_info->trans_lock);
2318 :
2319 : /*
2320 : * The thread has started/joined the transaction thus it holds the
2321 : * lockdep map as a reader. It has to release it before acquiring the
2322 : * lockdep map as a writer.
2323 : */
2324 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2325 0 : btrfs_might_wait_for_event(fs_info, btrfs_trans_num_writers);
2326 0 : wait_event(cur_trans->writer_wait,
2327 : atomic_read(&cur_trans->num_writers) == 1);
2328 :
2329 : /*
2330 : * Make lockdep happy by acquiring the state locks after
2331 : * btrfs_trans_num_writers is released. If we acquired the state locks
2332 : * before releasing the btrfs_trans_num_writers lock then lockdep would
2333 : * complain because we did not follow the reverse order unlocking rule.
2334 : */
2335 0 : btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2336 0 : btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2337 0 : btrfs_trans_state_lockdep_acquire(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2338 :
2339 : /*
2340 : * We've started the commit, clear the flag in case we were triggered to
2341 : * do an async commit but somebody else started before the transaction
2342 : * kthread could do the work.
2343 : */
2344 0 : clear_bit(BTRFS_FS_COMMIT_TRANS, &fs_info->flags);
2345 :
2346 0 : if (TRANS_ABORTED(cur_trans)) {
2347 0 : ret = cur_trans->aborted;
2348 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2349 0 : goto scrub_continue;
2350 : }
2351 : /*
2352 : * the reloc mutex makes sure that we stop
2353 : * the balancing code from coming in and moving
2354 : * extents around in the middle of the commit
2355 : */
2356 0 : mutex_lock(&fs_info->reloc_mutex);
2357 :
2358 : /*
2359 : * We needn't worry about the delayed items because we will
2360 : * deal with them in create_pending_snapshot(), which is the
2361 : * core function of the snapshot creation.
2362 : */
2363 0 : ret = create_pending_snapshots(trans);
2364 0 : if (ret)
2365 0 : goto unlock_reloc;
2366 :
2367 : /*
2368 : * We insert the dir indexes of the snapshots and update the inode
2369 : * of the snapshots' parents after the snapshot creation, so there
2370 : * are some delayed items which are not dealt with. Now deal with
2371 : * them.
2372 : *
2373 : * We needn't worry that this operation will corrupt the snapshots,
2374 : * because all the tree which are snapshoted will be forced to COW
2375 : * the nodes and leaves.
2376 : */
2377 0 : ret = btrfs_run_delayed_items(trans);
2378 0 : if (ret)
2379 0 : goto unlock_reloc;
2380 :
2381 0 : ret = btrfs_run_delayed_refs(trans, (unsigned long)-1);
2382 0 : if (ret)
2383 0 : goto unlock_reloc;
2384 :
2385 : /*
2386 : * make sure none of the code above managed to slip in a
2387 : * delayed item
2388 : */
2389 0 : btrfs_assert_delayed_root_empty(fs_info);
2390 :
2391 0 : WARN_ON(cur_trans != trans->transaction);
2392 :
2393 0 : ret = commit_fs_roots(trans);
2394 0 : if (ret)
2395 0 : goto unlock_reloc;
2396 :
2397 : /* commit_fs_roots gets rid of all the tree log roots, it is now
2398 : * safe to free the root of tree log roots
2399 : */
2400 0 : btrfs_free_log_root_tree(trans, fs_info);
2401 :
2402 : /*
2403 : * Since fs roots are all committed, we can get a quite accurate
2404 : * new_roots. So let's do quota accounting.
2405 : */
2406 0 : ret = btrfs_qgroup_account_extents(trans);
2407 0 : if (ret < 0)
2408 0 : goto unlock_reloc;
2409 :
2410 0 : ret = commit_cowonly_roots(trans);
2411 0 : if (ret)
2412 0 : goto unlock_reloc;
2413 :
2414 : /*
2415 : * The tasks which save the space cache and inode cache may also
2416 : * update ->aborted, check it.
2417 : */
2418 0 : if (TRANS_ABORTED(cur_trans)) {
2419 0 : ret = cur_trans->aborted;
2420 0 : goto unlock_reloc;
2421 : }
2422 :
2423 0 : cur_trans = fs_info->running_transaction;
2424 :
2425 0 : btrfs_set_root_node(&fs_info->tree_root->root_item,
2426 : fs_info->tree_root->node);
2427 0 : list_add_tail(&fs_info->tree_root->dirty_list,
2428 : &cur_trans->switch_commits);
2429 :
2430 0 : btrfs_set_root_node(&fs_info->chunk_root->root_item,
2431 : fs_info->chunk_root->node);
2432 0 : list_add_tail(&fs_info->chunk_root->dirty_list,
2433 : &cur_trans->switch_commits);
2434 :
2435 0 : if (btrfs_fs_incompat(fs_info, EXTENT_TREE_V2)) {
2436 0 : btrfs_set_root_node(&fs_info->block_group_root->root_item,
2437 : fs_info->block_group_root->node);
2438 0 : list_add_tail(&fs_info->block_group_root->dirty_list,
2439 : &cur_trans->switch_commits);
2440 : }
2441 :
2442 0 : switch_commit_roots(trans);
2443 :
2444 0 : ASSERT(list_empty(&cur_trans->dirty_bgs));
2445 0 : ASSERT(list_empty(&cur_trans->io_bgs));
2446 0 : update_super_roots(fs_info);
2447 :
2448 0 : btrfs_set_super_log_root(fs_info->super_copy, 0);
2449 0 : btrfs_set_super_log_root_level(fs_info->super_copy, 0);
2450 0 : memcpy(fs_info->super_for_commit, fs_info->super_copy,
2451 : sizeof(*fs_info->super_copy));
2452 :
2453 0 : btrfs_commit_device_sizes(cur_trans);
2454 :
2455 0 : clear_bit(BTRFS_FS_LOG1_ERR, &fs_info->flags);
2456 0 : clear_bit(BTRFS_FS_LOG2_ERR, &fs_info->flags);
2457 :
2458 0 : btrfs_trans_release_chunk_metadata(trans);
2459 :
2460 : /*
2461 : * Before changing the transaction state to TRANS_STATE_UNBLOCKED and
2462 : * setting fs_info->running_transaction to NULL, lock tree_log_mutex to
2463 : * make sure that before we commit our superblock, no other task can
2464 : * start a new transaction and commit a log tree before we commit our
2465 : * superblock. Anyone trying to commit a log tree locks this mutex before
2466 : * writing its superblock.
2467 : */
2468 0 : mutex_lock(&fs_info->tree_log_mutex);
2469 :
2470 0 : spin_lock(&fs_info->trans_lock);
2471 0 : cur_trans->state = TRANS_STATE_UNBLOCKED;
2472 0 : fs_info->running_transaction = NULL;
2473 0 : spin_unlock(&fs_info->trans_lock);
2474 0 : mutex_unlock(&fs_info->reloc_mutex);
2475 :
2476 0 : wake_up(&fs_info->transaction_wait);
2477 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2478 :
2479 : /* If we have features changed, wake up the cleaner to update sysfs. */
2480 0 : if (test_bit(BTRFS_FS_FEATURE_CHANGED, &fs_info->flags) &&
2481 0 : fs_info->cleaner_kthread)
2482 0 : wake_up_process(fs_info->cleaner_kthread);
2483 :
2484 0 : ret = btrfs_write_and_wait_transaction(trans);
2485 0 : if (ret) {
2486 0 : btrfs_handle_fs_error(fs_info, ret,
2487 : "Error while writing out transaction");
2488 0 : mutex_unlock(&fs_info->tree_log_mutex);
2489 0 : goto scrub_continue;
2490 : }
2491 :
2492 0 : ret = write_all_supers(fs_info, 0);
2493 : /*
2494 : * the super is written, we can safely allow the tree-loggers
2495 : * to go about their business
2496 : */
2497 0 : mutex_unlock(&fs_info->tree_log_mutex);
2498 0 : if (ret)
2499 0 : goto scrub_continue;
2500 :
2501 : /*
2502 : * We needn't acquire the lock here because there is no other task
2503 : * which can change it.
2504 : */
2505 0 : cur_trans->state = TRANS_STATE_SUPER_COMMITTED;
2506 0 : wake_up(&cur_trans->commit_wait);
2507 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2508 :
2509 0 : btrfs_finish_extent_commit(trans);
2510 :
2511 0 : if (test_bit(BTRFS_TRANS_HAVE_FREE_BGS, &cur_trans->flags))
2512 0 : btrfs_clear_space_info_full(fs_info);
2513 :
2514 0 : fs_info->last_trans_committed = cur_trans->transid;
2515 : /*
2516 : * We needn't acquire the lock here because there is no other task
2517 : * which can change it.
2518 : */
2519 0 : cur_trans->state = TRANS_STATE_COMPLETED;
2520 0 : wake_up(&cur_trans->commit_wait);
2521 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2522 :
2523 0 : spin_lock(&fs_info->trans_lock);
2524 0 : list_del_init(&cur_trans->list);
2525 0 : spin_unlock(&fs_info->trans_lock);
2526 :
2527 0 : btrfs_put_transaction(cur_trans);
2528 0 : btrfs_put_transaction(cur_trans);
2529 :
2530 0 : if (trans->type & __TRANS_FREEZABLE)
2531 0 : sb_end_intwrite(fs_info->sb);
2532 :
2533 0 : trace_btrfs_transaction_commit(fs_info);
2534 :
2535 0 : interval = ktime_get_ns() - start_time;
2536 :
2537 0 : btrfs_scrub_continue(fs_info);
2538 :
2539 0 : if (current->journal_info == trans)
2540 0 : current->journal_info = NULL;
2541 :
2542 0 : kmem_cache_free(btrfs_trans_handle_cachep, trans);
2543 :
2544 0 : update_commit_stats(fs_info, interval);
2545 :
2546 0 : return ret;
2547 :
2548 0 : unlock_reloc:
2549 0 : mutex_unlock(&fs_info->reloc_mutex);
2550 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_UNBLOCKED);
2551 0 : scrub_continue:
2552 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_SUPER_COMMITTED);
2553 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMPLETED);
2554 0 : btrfs_scrub_continue(fs_info);
2555 0 : cleanup_transaction:
2556 0 : btrfs_trans_release_metadata(trans);
2557 0 : btrfs_cleanup_pending_block_groups(trans);
2558 0 : btrfs_trans_release_chunk_metadata(trans);
2559 0 : trans->block_rsv = NULL;
2560 0 : btrfs_warn(fs_info, "Skipping commit of aborted transaction.");
2561 0 : if (current->journal_info == trans)
2562 0 : current->journal_info = NULL;
2563 0 : cleanup_transaction(trans, ret);
2564 :
2565 0 : return ret;
2566 :
2567 0 : lockdep_release:
2568 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_extwriters);
2569 0 : btrfs_lockdep_release(fs_info, btrfs_trans_num_writers);
2570 0 : goto cleanup_transaction;
2571 :
2572 0 : lockdep_trans_commit_start_release:
2573 0 : btrfs_trans_state_lockdep_release(fs_info, BTRFS_LOCKDEP_TRANS_COMMIT_START);
2574 0 : btrfs_end_transaction(trans);
2575 0 : return ret;
2576 : }
2577 :
2578 : /*
2579 : * return < 0 if error
2580 : * 0 if there are no more dead_roots at the time of call
2581 : * 1 there are more to be processed, call me again
2582 : *
2583 : * The return value indicates there are certainly more snapshots to delete, but
2584 : * if there comes a new one during processing, it may return 0. We don't mind,
2585 : * because btrfs_commit_super will poke cleaner thread and it will process it a
2586 : * few seconds later.
2587 : */
2588 0 : int btrfs_clean_one_deleted_snapshot(struct btrfs_fs_info *fs_info)
2589 : {
2590 0 : struct btrfs_root *root;
2591 0 : int ret;
2592 :
2593 0 : spin_lock(&fs_info->trans_lock);
2594 0 : if (list_empty(&fs_info->dead_roots)) {
2595 0 : spin_unlock(&fs_info->trans_lock);
2596 0 : return 0;
2597 : }
2598 0 : root = list_first_entry(&fs_info->dead_roots,
2599 : struct btrfs_root, root_list);
2600 0 : list_del_init(&root->root_list);
2601 0 : spin_unlock(&fs_info->trans_lock);
2602 :
2603 0 : btrfs_debug(fs_info, "cleaner removing %llu", root->root_key.objectid);
2604 :
2605 0 : btrfs_kill_all_delayed_nodes(root);
2606 :
2607 0 : if (btrfs_header_backref_rev(root->node) <
2608 : BTRFS_MIXED_BACKREF_REV)
2609 0 : ret = btrfs_drop_snapshot(root, 0, 0);
2610 : else
2611 0 : ret = btrfs_drop_snapshot(root, 1, 0);
2612 :
2613 0 : btrfs_put_root(root);
2614 0 : return (ret < 0) ? 0 : 1;
2615 : }
2616 :
2617 : /*
2618 : * We only mark the transaction aborted and then set the file system read-only.
2619 : * This will prevent new transactions from starting or trying to join this
2620 : * one.
2621 : *
2622 : * This means that error recovery at the call site is limited to freeing
2623 : * any local memory allocations and passing the error code up without
2624 : * further cleanup. The transaction should complete as it normally would
2625 : * in the call path but will return -EIO.
2626 : *
2627 : * We'll complete the cleanup in btrfs_end_transaction and
2628 : * btrfs_commit_transaction.
2629 : */
2630 0 : void __cold __btrfs_abort_transaction(struct btrfs_trans_handle *trans,
2631 : const char *function,
2632 : unsigned int line, int errno, bool first_hit)
2633 : {
2634 0 : struct btrfs_fs_info *fs_info = trans->fs_info;
2635 :
2636 0 : WRITE_ONCE(trans->aborted, errno);
2637 0 : WRITE_ONCE(trans->transaction->aborted, errno);
2638 0 : if (first_hit && errno == -ENOSPC)
2639 0 : btrfs_dump_space_info_for_trans_abort(fs_info);
2640 : /* Wake up anybody who may be waiting on this transaction */
2641 0 : wake_up(&fs_info->transaction_wait);
2642 0 : wake_up(&fs_info->transaction_blocked_wait);
2643 0 : __btrfs_handle_fs_error(fs_info, function, line, errno, NULL);
2644 0 : }
2645 :
2646 2 : int __init btrfs_transaction_init(void)
2647 : {
2648 2 : btrfs_trans_handle_cachep = kmem_cache_create("btrfs_trans_handle",
2649 : sizeof(struct btrfs_trans_handle), 0,
2650 : SLAB_TEMPORARY | SLAB_MEM_SPREAD, NULL);
2651 2 : if (!btrfs_trans_handle_cachep)
2652 0 : return -ENOMEM;
2653 : return 0;
2654 : }
2655 :
2656 0 : void __cold btrfs_transaction_exit(void)
2657 : {
2658 0 : kmem_cache_destroy(btrfs_trans_handle_cachep);
2659 0 : }
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