1 /*
2 * Copyright (C) 2007 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/fs.h>
20 #include <linux/slab.h>
21 #include <linux/sched.h>
22 #include <linux/writeback.h>
23 #include <linux/pagemap.h>
24 #include <linux/blkdev.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "locking.h"
29 #include "tree-log.h"
30 #include "inode-map.h"
31
32 #define BTRFS_ROOT_TRANS_TAG 0
33
put_transaction(struct btrfs_transaction * transaction)34 void put_transaction(struct btrfs_transaction *transaction)
35 {
36 WARN_ON(atomic_read(&transaction->use_count) == 0);
37 if (atomic_dec_and_test(&transaction->use_count)) {
38 BUG_ON(!list_empty(&transaction->list));
39 WARN_ON(transaction->delayed_refs.root.rb_node);
40 WARN_ON(!list_empty(&transaction->delayed_refs.seq_head));
41 memset(transaction, 0, sizeof(*transaction));
42 kmem_cache_free(btrfs_transaction_cachep, transaction);
43 }
44 }
45
switch_commit_root(struct btrfs_root * root)46 static noinline void switch_commit_root(struct btrfs_root *root)
47 {
48 free_extent_buffer(root->commit_root);
49 root->commit_root = btrfs_root_node(root);
50 }
51
52 /*
53 * either allocate a new transaction or hop into the existing one
54 */
join_transaction(struct btrfs_root * root,int nofail)55 static noinline int join_transaction(struct btrfs_root *root, int nofail)
56 {
57 struct btrfs_transaction *cur_trans;
58
59 spin_lock(&root->fs_info->trans_lock);
60 loop:
61 /* The file system has been taken offline. No new transactions. */
62 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
63 spin_unlock(&root->fs_info->trans_lock);
64 return -EROFS;
65 }
66
67 if (root->fs_info->trans_no_join) {
68 if (!nofail) {
69 spin_unlock(&root->fs_info->trans_lock);
70 return -EBUSY;
71 }
72 }
73
74 cur_trans = root->fs_info->running_transaction;
75 if (cur_trans) {
76 if (cur_trans->aborted) {
77 spin_unlock(&root->fs_info->trans_lock);
78 return cur_trans->aborted;
79 }
80 atomic_inc(&cur_trans->use_count);
81 atomic_inc(&cur_trans->num_writers);
82 cur_trans->num_joined++;
83 spin_unlock(&root->fs_info->trans_lock);
84 return 0;
85 }
86 spin_unlock(&root->fs_info->trans_lock);
87
88 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
89 if (!cur_trans)
90 return -ENOMEM;
91
92 spin_lock(&root->fs_info->trans_lock);
93 if (root->fs_info->running_transaction) {
94 /*
95 * someone started a transaction after we unlocked. Make sure
96 * to redo the trans_no_join checks above
97 */
98 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
99 cur_trans = root->fs_info->running_transaction;
100 goto loop;
101 }
102
103 atomic_set(&cur_trans->num_writers, 1);
104 cur_trans->num_joined = 0;
105 init_waitqueue_head(&cur_trans->writer_wait);
106 init_waitqueue_head(&cur_trans->commit_wait);
107 cur_trans->in_commit = 0;
108 cur_trans->blocked = 0;
109 /*
110 * One for this trans handle, one so it will live on until we
111 * commit the transaction.
112 */
113 atomic_set(&cur_trans->use_count, 2);
114 cur_trans->commit_done = 0;
115 cur_trans->start_time = get_seconds();
116
117 cur_trans->delayed_refs.root = RB_ROOT;
118 cur_trans->delayed_refs.num_entries = 0;
119 cur_trans->delayed_refs.num_heads_ready = 0;
120 cur_trans->delayed_refs.num_heads = 0;
121 cur_trans->delayed_refs.flushing = 0;
122 cur_trans->delayed_refs.run_delayed_start = 0;
123 cur_trans->delayed_refs.seq = 1;
124 init_waitqueue_head(&cur_trans->delayed_refs.seq_wait);
125 spin_lock_init(&cur_trans->commit_lock);
126 spin_lock_init(&cur_trans->delayed_refs.lock);
127 INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head);
128
129 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
130 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
131 extent_io_tree_init(&cur_trans->dirty_pages,
132 root->fs_info->btree_inode->i_mapping);
133 root->fs_info->generation++;
134 cur_trans->transid = root->fs_info->generation;
135 root->fs_info->running_transaction = cur_trans;
136 cur_trans->aborted = 0;
137 spin_unlock(&root->fs_info->trans_lock);
138
139 return 0;
140 }
141
142 /*
143 * this does all the record keeping required to make sure that a reference
144 * counted root is properly recorded in a given transaction. This is required
145 * to make sure the old root from before we joined the transaction is deleted
146 * when the transaction commits
147 */
record_root_in_trans(struct btrfs_trans_handle * trans,struct btrfs_root * root)148 static int record_root_in_trans(struct btrfs_trans_handle *trans,
149 struct btrfs_root *root)
150 {
151 if (root->ref_cows && root->last_trans < trans->transid) {
152 WARN_ON(root == root->fs_info->extent_root);
153 WARN_ON(root->commit_root != root->node);
154
155 /*
156 * see below for in_trans_setup usage rules
157 * we have the reloc mutex held now, so there
158 * is only one writer in this function
159 */
160 root->in_trans_setup = 1;
161
162 /* make sure readers find in_trans_setup before
163 * they find our root->last_trans update
164 */
165 smp_wmb();
166
167 spin_lock(&root->fs_info->fs_roots_radix_lock);
168 if (root->last_trans == trans->transid) {
169 spin_unlock(&root->fs_info->fs_roots_radix_lock);
170 return 0;
171 }
172 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
173 (unsigned long)root->root_key.objectid,
174 BTRFS_ROOT_TRANS_TAG);
175 spin_unlock(&root->fs_info->fs_roots_radix_lock);
176 root->last_trans = trans->transid;
177
178 /* this is pretty tricky. We don't want to
179 * take the relocation lock in btrfs_record_root_in_trans
180 * unless we're really doing the first setup for this root in
181 * this transaction.
182 *
183 * Normally we'd use root->last_trans as a flag to decide
184 * if we want to take the expensive mutex.
185 *
186 * But, we have to set root->last_trans before we
187 * init the relocation root, otherwise, we trip over warnings
188 * in ctree.c. The solution used here is to flag ourselves
189 * with root->in_trans_setup. When this is 1, we're still
190 * fixing up the reloc trees and everyone must wait.
191 *
192 * When this is zero, they can trust root->last_trans and fly
193 * through btrfs_record_root_in_trans without having to take the
194 * lock. smp_wmb() makes sure that all the writes above are
195 * done before we pop in the zero below
196 */
197 btrfs_init_reloc_root(trans, root);
198 smp_wmb();
199 root->in_trans_setup = 0;
200 }
201 return 0;
202 }
203
204
btrfs_record_root_in_trans(struct btrfs_trans_handle * trans,struct btrfs_root * root)205 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
206 struct btrfs_root *root)
207 {
208 if (!root->ref_cows)
209 return 0;
210
211 /*
212 * see record_root_in_trans for comments about in_trans_setup usage
213 * and barriers
214 */
215 smp_rmb();
216 if (root->last_trans == trans->transid &&
217 !root->in_trans_setup)
218 return 0;
219
220 mutex_lock(&root->fs_info->reloc_mutex);
221 record_root_in_trans(trans, root);
222 mutex_unlock(&root->fs_info->reloc_mutex);
223
224 return 0;
225 }
226
227 /* wait for commit against the current transaction to become unblocked
228 * when this is done, it is safe to start a new transaction, but the current
229 * transaction might not be fully on disk.
230 */
wait_current_trans(struct btrfs_root * root)231 static void wait_current_trans(struct btrfs_root *root)
232 {
233 struct btrfs_transaction *cur_trans;
234
235 spin_lock(&root->fs_info->trans_lock);
236 cur_trans = root->fs_info->running_transaction;
237 if (cur_trans && cur_trans->blocked) {
238 atomic_inc(&cur_trans->use_count);
239 spin_unlock(&root->fs_info->trans_lock);
240
241 wait_event(root->fs_info->transaction_wait,
242 !cur_trans->blocked);
243 put_transaction(cur_trans);
244 } else {
245 spin_unlock(&root->fs_info->trans_lock);
246 }
247 }
248
249 enum btrfs_trans_type {
250 TRANS_START,
251 TRANS_JOIN,
252 TRANS_USERSPACE,
253 TRANS_JOIN_NOLOCK,
254 };
255
may_wait_transaction(struct btrfs_root * root,int type)256 static int may_wait_transaction(struct btrfs_root *root, int type)
257 {
258 if (root->fs_info->log_root_recovering)
259 return 0;
260
261 if (type == TRANS_USERSPACE)
262 return 1;
263
264 if (type == TRANS_START &&
265 !atomic_read(&root->fs_info->open_ioctl_trans))
266 return 1;
267
268 return 0;
269 }
270
start_transaction(struct btrfs_root * root,u64 num_items,int type)271 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
272 u64 num_items, int type)
273 {
274 struct btrfs_trans_handle *h;
275 struct btrfs_transaction *cur_trans;
276 u64 num_bytes = 0;
277 int ret;
278
279 if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
280 return ERR_PTR(-EROFS);
281
282 if (current->journal_info) {
283 WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
284 h = current->journal_info;
285 h->use_count++;
286 h->orig_rsv = h->block_rsv;
287 h->block_rsv = NULL;
288 goto got_it;
289 }
290
291 /*
292 * Do the reservation before we join the transaction so we can do all
293 * the appropriate flushing if need be.
294 */
295 if (num_items > 0 && root != root->fs_info->chunk_root) {
296 num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
297 ret = btrfs_block_rsv_add(root,
298 &root->fs_info->trans_block_rsv,
299 num_bytes);
300 if (ret)
301 return ERR_PTR(ret);
302 }
303 again:
304 h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
305 if (!h)
306 return ERR_PTR(-ENOMEM);
307
308 if (may_wait_transaction(root, type))
309 wait_current_trans(root);
310
311 do {
312 ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
313 if (ret == -EBUSY)
314 wait_current_trans(root);
315 } while (ret == -EBUSY);
316
317 if (ret < 0) {
318 kmem_cache_free(btrfs_trans_handle_cachep, h);
319 return ERR_PTR(ret);
320 }
321
322 cur_trans = root->fs_info->running_transaction;
323
324 h->transid = cur_trans->transid;
325 h->transaction = cur_trans;
326 h->blocks_used = 0;
327 h->bytes_reserved = 0;
328 h->delayed_ref_updates = 0;
329 h->use_count = 1;
330 h->block_rsv = NULL;
331 h->orig_rsv = NULL;
332 h->aborted = 0;
333
334 smp_mb();
335 if (cur_trans->blocked && may_wait_transaction(root, type)) {
336 btrfs_commit_transaction(h, root);
337 goto again;
338 }
339
340 if (num_bytes) {
341 trace_btrfs_space_reservation(root->fs_info, "transaction",
342 h->transid, num_bytes, 1);
343 h->block_rsv = &root->fs_info->trans_block_rsv;
344 h->bytes_reserved = num_bytes;
345 }
346
347 got_it:
348 btrfs_record_root_in_trans(h, root);
349
350 if (!current->journal_info && type != TRANS_USERSPACE)
351 current->journal_info = h;
352 return h;
353 }
354
btrfs_start_transaction(struct btrfs_root * root,int num_items)355 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
356 int num_items)
357 {
358 return start_transaction(root, num_items, TRANS_START);
359 }
btrfs_join_transaction(struct btrfs_root * root)360 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
361 {
362 return start_transaction(root, 0, TRANS_JOIN);
363 }
364
btrfs_join_transaction_nolock(struct btrfs_root * root)365 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
366 {
367 return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
368 }
369
btrfs_start_ioctl_transaction(struct btrfs_root * root)370 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
371 {
372 return start_transaction(root, 0, TRANS_USERSPACE);
373 }
374
375 /* wait for a transaction commit to be fully complete */
wait_for_commit(struct btrfs_root * root,struct btrfs_transaction * commit)376 static noinline void wait_for_commit(struct btrfs_root *root,
377 struct btrfs_transaction *commit)
378 {
379 wait_event(commit->commit_wait, commit->commit_done);
380 }
381
btrfs_wait_for_commit(struct btrfs_root * root,u64 transid)382 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
383 {
384 struct btrfs_transaction *cur_trans = NULL, *t;
385 int ret;
386
387 ret = 0;
388 if (transid) {
389 if (transid <= root->fs_info->last_trans_committed)
390 goto out;
391
392 /* find specified transaction */
393 spin_lock(&root->fs_info->trans_lock);
394 list_for_each_entry(t, &root->fs_info->trans_list, list) {
395 if (t->transid == transid) {
396 cur_trans = t;
397 atomic_inc(&cur_trans->use_count);
398 break;
399 }
400 if (t->transid > transid)
401 break;
402 }
403 spin_unlock(&root->fs_info->trans_lock);
404 ret = -EINVAL;
405 if (!cur_trans)
406 goto out; /* bad transid */
407 } else {
408 /* find newest transaction that is committing | committed */
409 spin_lock(&root->fs_info->trans_lock);
410 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
411 list) {
412 if (t->in_commit) {
413 if (t->commit_done)
414 break;
415 cur_trans = t;
416 atomic_inc(&cur_trans->use_count);
417 break;
418 }
419 }
420 spin_unlock(&root->fs_info->trans_lock);
421 if (!cur_trans)
422 goto out; /* nothing committing|committed */
423 }
424
425 wait_for_commit(root, cur_trans);
426
427 put_transaction(cur_trans);
428 ret = 0;
429 out:
430 return ret;
431 }
432
btrfs_throttle(struct btrfs_root * root)433 void btrfs_throttle(struct btrfs_root *root)
434 {
435 if (!atomic_read(&root->fs_info->open_ioctl_trans))
436 wait_current_trans(root);
437 }
438
should_end_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)439 static int should_end_transaction(struct btrfs_trans_handle *trans,
440 struct btrfs_root *root)
441 {
442 int ret;
443
444 ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
445 return ret ? 1 : 0;
446 }
447
btrfs_should_end_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)448 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
449 struct btrfs_root *root)
450 {
451 struct btrfs_transaction *cur_trans = trans->transaction;
452 struct btrfs_block_rsv *rsv = trans->block_rsv;
453 int updates;
454 int err;
455
456 smp_mb();
457 if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
458 return 1;
459
460 /*
461 * We need to do this in case we're deleting csums so the global block
462 * rsv get's used instead of the csum block rsv.
463 */
464 trans->block_rsv = NULL;
465
466 updates = trans->delayed_ref_updates;
467 trans->delayed_ref_updates = 0;
468 if (updates) {
469 err = btrfs_run_delayed_refs(trans, root, updates);
470 if (err) /* Error code will also eval true */
471 return err;
472 }
473
474 trans->block_rsv = rsv;
475
476 return should_end_transaction(trans, root);
477 }
478
__btrfs_end_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root,int throttle,int lock)479 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
480 struct btrfs_root *root, int throttle, int lock)
481 {
482 struct btrfs_transaction *cur_trans = trans->transaction;
483 struct btrfs_fs_info *info = root->fs_info;
484 int count = 0;
485 int err = 0;
486
487 if (--trans->use_count) {
488 trans->block_rsv = trans->orig_rsv;
489 return 0;
490 }
491
492 btrfs_trans_release_metadata(trans, root);
493 trans->block_rsv = NULL;
494 while (count < 2) {
495 unsigned long cur = trans->delayed_ref_updates;
496 trans->delayed_ref_updates = 0;
497 if (cur &&
498 trans->transaction->delayed_refs.num_heads_ready > 64) {
499 trans->delayed_ref_updates = 0;
500 btrfs_run_delayed_refs(trans, root, cur);
501 } else {
502 break;
503 }
504 count++;
505 }
506
507 if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
508 should_end_transaction(trans, root)) {
509 trans->transaction->blocked = 1;
510 smp_wmb();
511 }
512
513 if (lock && cur_trans->blocked && !cur_trans->in_commit) {
514 if (throttle) {
515 /*
516 * We may race with somebody else here so end up having
517 * to call end_transaction on ourselves again, so inc
518 * our use_count.
519 */
520 trans->use_count++;
521 return btrfs_commit_transaction(trans, root);
522 } else {
523 wake_up_process(info->transaction_kthread);
524 }
525 }
526
527 WARN_ON(cur_trans != info->running_transaction);
528 WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
529 atomic_dec(&cur_trans->num_writers);
530
531 smp_mb();
532 if (waitqueue_active(&cur_trans->writer_wait))
533 wake_up(&cur_trans->writer_wait);
534 put_transaction(cur_trans);
535
536 if (current->journal_info == trans)
537 current->journal_info = NULL;
538
539 if (throttle)
540 btrfs_run_delayed_iputs(root);
541
542 if (trans->aborted ||
543 root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
544 err = -EIO;
545 }
546
547 memset(trans, 0, sizeof(*trans));
548 kmem_cache_free(btrfs_trans_handle_cachep, trans);
549 return err;
550 }
551
btrfs_end_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)552 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
553 struct btrfs_root *root)
554 {
555 int ret;
556
557 ret = __btrfs_end_transaction(trans, root, 0, 1);
558 if (ret)
559 return ret;
560 return 0;
561 }
562
btrfs_end_transaction_throttle(struct btrfs_trans_handle * trans,struct btrfs_root * root)563 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
564 struct btrfs_root *root)
565 {
566 int ret;
567
568 ret = __btrfs_end_transaction(trans, root, 1, 1);
569 if (ret)
570 return ret;
571 return 0;
572 }
573
btrfs_end_transaction_nolock(struct btrfs_trans_handle * trans,struct btrfs_root * root)574 int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
575 struct btrfs_root *root)
576 {
577 int ret;
578
579 ret = __btrfs_end_transaction(trans, root, 0, 0);
580 if (ret)
581 return ret;
582 return 0;
583 }
584
btrfs_end_transaction_dmeta(struct btrfs_trans_handle * trans,struct btrfs_root * root)585 int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
586 struct btrfs_root *root)
587 {
588 return __btrfs_end_transaction(trans, root, 1, 1);
589 }
590
591 /*
592 * when btree blocks are allocated, they have some corresponding bits set for
593 * them in one of two extent_io trees. This is used to make sure all of
594 * those extents are sent to disk but does not wait on them
595 */
btrfs_write_marked_extents(struct btrfs_root * root,struct extent_io_tree * dirty_pages,int mark)596 int btrfs_write_marked_extents(struct btrfs_root *root,
597 struct extent_io_tree *dirty_pages, int mark)
598 {
599 int err = 0;
600 int werr = 0;
601 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
602 u64 start = 0;
603 u64 end;
604
605 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
606 mark)) {
607 convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark,
608 GFP_NOFS);
609 err = filemap_fdatawrite_range(mapping, start, end);
610 if (err)
611 werr = err;
612 cond_resched();
613 start = end + 1;
614 }
615 if (err)
616 werr = err;
617 return werr;
618 }
619
620 /*
621 * when btree blocks are allocated, they have some corresponding bits set for
622 * them in one of two extent_io trees. This is used to make sure all of
623 * those extents are on disk for transaction or log commit. We wait
624 * on all the pages and clear them from the dirty pages state tree
625 */
btrfs_wait_marked_extents(struct btrfs_root * root,struct extent_io_tree * dirty_pages,int mark)626 int btrfs_wait_marked_extents(struct btrfs_root *root,
627 struct extent_io_tree *dirty_pages, int mark)
628 {
629 int err = 0;
630 int werr = 0;
631 struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
632 u64 start = 0;
633 u64 end;
634
635 while (!find_first_extent_bit(dirty_pages, start, &start, &end,
636 EXTENT_NEED_WAIT)) {
637 clear_extent_bits(dirty_pages, start, end, EXTENT_NEED_WAIT, GFP_NOFS);
638 err = filemap_fdatawait_range(mapping, start, end);
639 if (err)
640 werr = err;
641 cond_resched();
642 start = end + 1;
643 }
644 if (err)
645 werr = err;
646 return werr;
647 }
648
649 /*
650 * when btree blocks are allocated, they have some corresponding bits set for
651 * them in one of two extent_io trees. This is used to make sure all of
652 * those extents are on disk for transaction or log commit
653 */
btrfs_write_and_wait_marked_extents(struct btrfs_root * root,struct extent_io_tree * dirty_pages,int mark)654 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
655 struct extent_io_tree *dirty_pages, int mark)
656 {
657 int ret;
658 int ret2;
659
660 ret = btrfs_write_marked_extents(root, dirty_pages, mark);
661 ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
662
663 if (ret)
664 return ret;
665 if (ret2)
666 return ret2;
667 return 0;
668 }
669
btrfs_write_and_wait_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)670 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
671 struct btrfs_root *root)
672 {
673 if (!trans || !trans->transaction) {
674 struct inode *btree_inode;
675 btree_inode = root->fs_info->btree_inode;
676 return filemap_write_and_wait(btree_inode->i_mapping);
677 }
678 return btrfs_write_and_wait_marked_extents(root,
679 &trans->transaction->dirty_pages,
680 EXTENT_DIRTY);
681 }
682
683 /*
684 * this is used to update the root pointer in the tree of tree roots.
685 *
686 * But, in the case of the extent allocation tree, updating the root
687 * pointer may allocate blocks which may change the root of the extent
688 * allocation tree.
689 *
690 * So, this loops and repeats and makes sure the cowonly root didn't
691 * change while the root pointer was being updated in the metadata.
692 */
update_cowonly_root(struct btrfs_trans_handle * trans,struct btrfs_root * root)693 static int update_cowonly_root(struct btrfs_trans_handle *trans,
694 struct btrfs_root *root)
695 {
696 int ret;
697 u64 old_root_bytenr;
698 u64 old_root_used;
699 struct btrfs_root *tree_root = root->fs_info->tree_root;
700
701 old_root_used = btrfs_root_used(&root->root_item);
702 btrfs_write_dirty_block_groups(trans, root);
703
704 while (1) {
705 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
706 if (old_root_bytenr == root->node->start &&
707 old_root_used == btrfs_root_used(&root->root_item))
708 break;
709
710 btrfs_set_root_node(&root->root_item, root->node);
711 ret = btrfs_update_root(trans, tree_root,
712 &root->root_key,
713 &root->root_item);
714 if (ret)
715 return ret;
716
717 old_root_used = btrfs_root_used(&root->root_item);
718 ret = btrfs_write_dirty_block_groups(trans, root);
719 if (ret)
720 return ret;
721 }
722
723 if (root != root->fs_info->extent_root)
724 switch_commit_root(root);
725
726 return 0;
727 }
728
729 /*
730 * update all the cowonly tree roots on disk
731 *
732 * The error handling in this function may not be obvious. Any of the
733 * failures will cause the file system to go offline. We still need
734 * to clean up the delayed refs.
735 */
commit_cowonly_roots(struct btrfs_trans_handle * trans,struct btrfs_root * root)736 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
737 struct btrfs_root *root)
738 {
739 struct btrfs_fs_info *fs_info = root->fs_info;
740 struct list_head *next;
741 struct extent_buffer *eb;
742 int ret;
743
744 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
745 if (ret)
746 return ret;
747
748 eb = btrfs_lock_root_node(fs_info->tree_root);
749 ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
750 0, &eb);
751 btrfs_tree_unlock(eb);
752 free_extent_buffer(eb);
753
754 if (ret)
755 return ret;
756
757 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
758 if (ret)
759 return ret;
760
761 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
762 next = fs_info->dirty_cowonly_roots.next;
763 list_del_init(next);
764 root = list_entry(next, struct btrfs_root, dirty_list);
765
766 ret = update_cowonly_root(trans, root);
767 if (ret)
768 return ret;
769 }
770
771 down_write(&fs_info->extent_commit_sem);
772 switch_commit_root(fs_info->extent_root);
773 up_write(&fs_info->extent_commit_sem);
774
775 return 0;
776 }
777
778 /*
779 * dead roots are old snapshots that need to be deleted. This allocates
780 * a dirty root struct and adds it into the list of dead roots that need to
781 * be deleted
782 */
btrfs_add_dead_root(struct btrfs_root * root)783 int btrfs_add_dead_root(struct btrfs_root *root)
784 {
785 spin_lock(&root->fs_info->trans_lock);
786 list_add(&root->root_list, &root->fs_info->dead_roots);
787 spin_unlock(&root->fs_info->trans_lock);
788 return 0;
789 }
790
791 /*
792 * update all the cowonly tree roots on disk
793 */
commit_fs_roots(struct btrfs_trans_handle * trans,struct btrfs_root * root)794 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
795 struct btrfs_root *root)
796 {
797 struct btrfs_root *gang[8];
798 struct btrfs_fs_info *fs_info = root->fs_info;
799 int i;
800 int ret;
801 int err = 0;
802
803 spin_lock(&fs_info->fs_roots_radix_lock);
804 while (1) {
805 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
806 (void **)gang, 0,
807 ARRAY_SIZE(gang),
808 BTRFS_ROOT_TRANS_TAG);
809 if (ret == 0)
810 break;
811 for (i = 0; i < ret; i++) {
812 root = gang[i];
813 radix_tree_tag_clear(&fs_info->fs_roots_radix,
814 (unsigned long)root->root_key.objectid,
815 BTRFS_ROOT_TRANS_TAG);
816 spin_unlock(&fs_info->fs_roots_radix_lock);
817
818 btrfs_free_log(trans, root);
819 btrfs_update_reloc_root(trans, root);
820 btrfs_orphan_commit_root(trans, root);
821
822 btrfs_save_ino_cache(root, trans);
823
824 /* see comments in should_cow_block() */
825 root->force_cow = 0;
826 smp_wmb();
827
828 if (root->commit_root != root->node) {
829 mutex_lock(&root->fs_commit_mutex);
830 switch_commit_root(root);
831 btrfs_unpin_free_ino(root);
832 mutex_unlock(&root->fs_commit_mutex);
833
834 btrfs_set_root_node(&root->root_item,
835 root->node);
836 }
837
838 err = btrfs_update_root(trans, fs_info->tree_root,
839 &root->root_key,
840 &root->root_item);
841 spin_lock(&fs_info->fs_roots_radix_lock);
842 if (err)
843 break;
844 }
845 }
846 spin_unlock(&fs_info->fs_roots_radix_lock);
847 return err;
848 }
849
850 /*
851 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
852 * otherwise every leaf in the btree is read and defragged.
853 */
btrfs_defrag_root(struct btrfs_root * root,int cacheonly)854 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
855 {
856 struct btrfs_fs_info *info = root->fs_info;
857 struct btrfs_trans_handle *trans;
858 int ret;
859 unsigned long nr;
860
861 if (xchg(&root->defrag_running, 1))
862 return 0;
863
864 while (1) {
865 trans = btrfs_start_transaction(root, 0);
866 if (IS_ERR(trans))
867 return PTR_ERR(trans);
868
869 ret = btrfs_defrag_leaves(trans, root, cacheonly);
870
871 nr = trans->blocks_used;
872 btrfs_end_transaction(trans, root);
873 btrfs_btree_balance_dirty(info->tree_root, nr);
874 cond_resched();
875
876 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
877 break;
878 }
879 root->defrag_running = 0;
880 return ret;
881 }
882
883 /*
884 * new snapshots need to be created at a very specific time in the
885 * transaction commit. This does the actual creation
886 */
create_pending_snapshot(struct btrfs_trans_handle * trans,struct btrfs_fs_info * fs_info,struct btrfs_pending_snapshot * pending)887 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
888 struct btrfs_fs_info *fs_info,
889 struct btrfs_pending_snapshot *pending)
890 {
891 struct btrfs_key key;
892 struct btrfs_root_item *new_root_item;
893 struct btrfs_root *tree_root = fs_info->tree_root;
894 struct btrfs_root *root = pending->root;
895 struct btrfs_root *parent_root;
896 struct btrfs_block_rsv *rsv;
897 struct inode *parent_inode;
898 struct dentry *parent;
899 struct dentry *dentry;
900 struct extent_buffer *tmp;
901 struct extent_buffer *old;
902 int ret;
903 u64 to_reserve = 0;
904 u64 index = 0;
905 u64 objectid;
906 u64 root_flags;
907
908 rsv = trans->block_rsv;
909
910 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
911 if (!new_root_item) {
912 ret = pending->error = -ENOMEM;
913 goto fail;
914 }
915
916 ret = btrfs_find_free_objectid(tree_root, &objectid);
917 if (ret) {
918 pending->error = ret;
919 goto fail;
920 }
921
922 btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
923
924 if (to_reserve > 0) {
925 ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
926 to_reserve);
927 if (ret) {
928 pending->error = ret;
929 goto fail;
930 }
931 }
932
933 key.objectid = objectid;
934 key.offset = (u64)-1;
935 key.type = BTRFS_ROOT_ITEM_KEY;
936
937 trans->block_rsv = &pending->block_rsv;
938
939 dentry = pending->dentry;
940 parent = dget_parent(dentry);
941 parent_inode = parent->d_inode;
942 parent_root = BTRFS_I(parent_inode)->root;
943 record_root_in_trans(trans, parent_root);
944
945 /*
946 * insert the directory item
947 */
948 ret = btrfs_set_inode_index(parent_inode, &index);
949 BUG_ON(ret); /* -ENOMEM */
950 ret = btrfs_insert_dir_item(trans, parent_root,
951 dentry->d_name.name, dentry->d_name.len,
952 parent_inode, &key,
953 BTRFS_FT_DIR, index);
954 if (ret == -EEXIST) {
955 pending->error = -EEXIST;
956 dput(parent);
957 goto fail;
958 } else if (ret) {
959 goto abort_trans_dput;
960 }
961
962 btrfs_i_size_write(parent_inode, parent_inode->i_size +
963 dentry->d_name.len * 2);
964 ret = btrfs_update_inode(trans, parent_root, parent_inode);
965 if (ret)
966 goto abort_trans_dput;
967
968 /*
969 * pull in the delayed directory update
970 * and the delayed inode item
971 * otherwise we corrupt the FS during
972 * snapshot
973 */
974 ret = btrfs_run_delayed_items(trans, root);
975 if (ret) { /* Transaction aborted */
976 dput(parent);
977 goto fail;
978 }
979
980 record_root_in_trans(trans, root);
981 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
982 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
983 btrfs_check_and_init_root_item(new_root_item);
984
985 root_flags = btrfs_root_flags(new_root_item);
986 if (pending->readonly)
987 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
988 else
989 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
990 btrfs_set_root_flags(new_root_item, root_flags);
991
992 old = btrfs_lock_root_node(root);
993 ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
994 if (ret) {
995 btrfs_tree_unlock(old);
996 free_extent_buffer(old);
997 goto abort_trans_dput;
998 }
999
1000 btrfs_set_lock_blocking(old);
1001
1002 ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1003 /* clean up in any case */
1004 btrfs_tree_unlock(old);
1005 free_extent_buffer(old);
1006 if (ret)
1007 goto abort_trans_dput;
1008
1009 /* see comments in should_cow_block() */
1010 root->force_cow = 1;
1011 smp_wmb();
1012
1013 btrfs_set_root_node(new_root_item, tmp);
1014 /* record when the snapshot was created in key.offset */
1015 key.offset = trans->transid;
1016 ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1017 btrfs_tree_unlock(tmp);
1018 free_extent_buffer(tmp);
1019 if (ret)
1020 goto abort_trans_dput;
1021
1022 /*
1023 * insert root back/forward references
1024 */
1025 ret = btrfs_add_root_ref(trans, tree_root, objectid,
1026 parent_root->root_key.objectid,
1027 btrfs_ino(parent_inode), index,
1028 dentry->d_name.name, dentry->d_name.len);
1029 dput(parent);
1030 if (ret)
1031 goto fail;
1032
1033 key.offset = (u64)-1;
1034 pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1035 if (IS_ERR(pending->snap)) {
1036 ret = PTR_ERR(pending->snap);
1037 goto abort_trans;
1038 }
1039
1040 ret = btrfs_reloc_post_snapshot(trans, pending);
1041 if (ret)
1042 goto abort_trans;
1043 ret = 0;
1044 fail:
1045 kfree(new_root_item);
1046 trans->block_rsv = rsv;
1047 btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1048 return ret;
1049
1050 abort_trans_dput:
1051 dput(parent);
1052 abort_trans:
1053 btrfs_abort_transaction(trans, root, ret);
1054 goto fail;
1055 }
1056
1057 /*
1058 * create all the snapshots we've scheduled for creation
1059 */
create_pending_snapshots(struct btrfs_trans_handle * trans,struct btrfs_fs_info * fs_info)1060 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1061 struct btrfs_fs_info *fs_info)
1062 {
1063 struct btrfs_pending_snapshot *pending;
1064 struct list_head *head = &trans->transaction->pending_snapshots;
1065
1066 list_for_each_entry(pending, head, list)
1067 create_pending_snapshot(trans, fs_info, pending);
1068 return 0;
1069 }
1070
update_super_roots(struct btrfs_root * root)1071 static void update_super_roots(struct btrfs_root *root)
1072 {
1073 struct btrfs_root_item *root_item;
1074 struct btrfs_super_block *super;
1075
1076 super = root->fs_info->super_copy;
1077
1078 root_item = &root->fs_info->chunk_root->root_item;
1079 super->chunk_root = root_item->bytenr;
1080 super->chunk_root_generation = root_item->generation;
1081 super->chunk_root_level = root_item->level;
1082
1083 root_item = &root->fs_info->tree_root->root_item;
1084 super->root = root_item->bytenr;
1085 super->generation = root_item->generation;
1086 super->root_level = root_item->level;
1087 if (btrfs_test_opt(root, SPACE_CACHE))
1088 super->cache_generation = root_item->generation;
1089 }
1090
btrfs_transaction_in_commit(struct btrfs_fs_info * info)1091 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1092 {
1093 int ret = 0;
1094 spin_lock(&info->trans_lock);
1095 if (info->running_transaction)
1096 ret = info->running_transaction->in_commit;
1097 spin_unlock(&info->trans_lock);
1098 return ret;
1099 }
1100
btrfs_transaction_blocked(struct btrfs_fs_info * info)1101 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1102 {
1103 int ret = 0;
1104 spin_lock(&info->trans_lock);
1105 if (info->running_transaction)
1106 ret = info->running_transaction->blocked;
1107 spin_unlock(&info->trans_lock);
1108 return ret;
1109 }
1110
1111 /*
1112 * wait for the current transaction commit to start and block subsequent
1113 * transaction joins
1114 */
wait_current_trans_commit_start(struct btrfs_root * root,struct btrfs_transaction * trans)1115 static void wait_current_trans_commit_start(struct btrfs_root *root,
1116 struct btrfs_transaction *trans)
1117 {
1118 wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
1119 }
1120
1121 /*
1122 * wait for the current transaction to start and then become unblocked.
1123 * caller holds ref.
1124 */
wait_current_trans_commit_start_and_unblock(struct btrfs_root * root,struct btrfs_transaction * trans)1125 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1126 struct btrfs_transaction *trans)
1127 {
1128 wait_event(root->fs_info->transaction_wait,
1129 trans->commit_done || (trans->in_commit && !trans->blocked));
1130 }
1131
1132 /*
1133 * commit transactions asynchronously. once btrfs_commit_transaction_async
1134 * returns, any subsequent transaction will not be allowed to join.
1135 */
1136 struct btrfs_async_commit {
1137 struct btrfs_trans_handle *newtrans;
1138 struct btrfs_root *root;
1139 struct delayed_work work;
1140 };
1141
do_async_commit(struct work_struct * work)1142 static void do_async_commit(struct work_struct *work)
1143 {
1144 struct btrfs_async_commit *ac =
1145 container_of(work, struct btrfs_async_commit, work.work);
1146
1147 btrfs_commit_transaction(ac->newtrans, ac->root);
1148 kfree(ac);
1149 }
1150
btrfs_commit_transaction_async(struct btrfs_trans_handle * trans,struct btrfs_root * root,int wait_for_unblock)1151 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1152 struct btrfs_root *root,
1153 int wait_for_unblock)
1154 {
1155 struct btrfs_async_commit *ac;
1156 struct btrfs_transaction *cur_trans;
1157
1158 ac = kmalloc(sizeof(*ac), GFP_NOFS);
1159 if (!ac)
1160 return -ENOMEM;
1161
1162 INIT_DELAYED_WORK(&ac->work, do_async_commit);
1163 ac->root = root;
1164 ac->newtrans = btrfs_join_transaction(root);
1165 if (IS_ERR(ac->newtrans)) {
1166 int err = PTR_ERR(ac->newtrans);
1167 kfree(ac);
1168 return err;
1169 }
1170
1171 /* take transaction reference */
1172 cur_trans = trans->transaction;
1173 atomic_inc(&cur_trans->use_count);
1174
1175 btrfs_end_transaction(trans, root);
1176 schedule_delayed_work(&ac->work, 0);
1177
1178 /* wait for transaction to start and unblock */
1179 if (wait_for_unblock)
1180 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1181 else
1182 wait_current_trans_commit_start(root, cur_trans);
1183
1184 if (current->journal_info == trans)
1185 current->journal_info = NULL;
1186
1187 put_transaction(cur_trans);
1188 return 0;
1189 }
1190
1191
cleanup_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)1192 static void cleanup_transaction(struct btrfs_trans_handle *trans,
1193 struct btrfs_root *root)
1194 {
1195 struct btrfs_transaction *cur_trans = trans->transaction;
1196
1197 WARN_ON(trans->use_count > 1);
1198
1199 spin_lock(&root->fs_info->trans_lock);
1200 list_del_init(&cur_trans->list);
1201 spin_unlock(&root->fs_info->trans_lock);
1202
1203 btrfs_cleanup_one_transaction(trans->transaction, root);
1204
1205 put_transaction(cur_trans);
1206 put_transaction(cur_trans);
1207
1208 trace_btrfs_transaction_commit(root);
1209
1210 btrfs_scrub_continue(root);
1211
1212 if (current->journal_info == trans)
1213 current->journal_info = NULL;
1214
1215 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1216 }
1217
1218 /*
1219 * btrfs_transaction state sequence:
1220 * in_commit = 0, blocked = 0 (initial)
1221 * in_commit = 1, blocked = 1
1222 * blocked = 0
1223 * commit_done = 1
1224 */
btrfs_commit_transaction(struct btrfs_trans_handle * trans,struct btrfs_root * root)1225 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1226 struct btrfs_root *root)
1227 {
1228 unsigned long joined = 0;
1229 struct btrfs_transaction *cur_trans = trans->transaction;
1230 struct btrfs_transaction *prev_trans = NULL;
1231 DEFINE_WAIT(wait);
1232 int ret = -EIO;
1233 int should_grow = 0;
1234 unsigned long now = get_seconds();
1235 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1236
1237 btrfs_run_ordered_operations(root, 0);
1238
1239 btrfs_trans_release_metadata(trans, root);
1240 trans->block_rsv = NULL;
1241
1242 if (cur_trans->aborted)
1243 goto cleanup_transaction;
1244
1245 /* make a pass through all the delayed refs we have so far
1246 * any runnings procs may add more while we are here
1247 */
1248 ret = btrfs_run_delayed_refs(trans, root, 0);
1249 if (ret)
1250 goto cleanup_transaction;
1251
1252 cur_trans = trans->transaction;
1253
1254 /*
1255 * set the flushing flag so procs in this transaction have to
1256 * start sending their work down.
1257 */
1258 cur_trans->delayed_refs.flushing = 1;
1259
1260 ret = btrfs_run_delayed_refs(trans, root, 0);
1261 if (ret)
1262 goto cleanup_transaction;
1263
1264 spin_lock(&cur_trans->commit_lock);
1265 if (cur_trans->in_commit) {
1266 spin_unlock(&cur_trans->commit_lock);
1267 atomic_inc(&cur_trans->use_count);
1268 ret = btrfs_end_transaction(trans, root);
1269
1270 wait_for_commit(root, cur_trans);
1271
1272 put_transaction(cur_trans);
1273
1274 return ret;
1275 }
1276
1277 trans->transaction->in_commit = 1;
1278 trans->transaction->blocked = 1;
1279 spin_unlock(&cur_trans->commit_lock);
1280 wake_up(&root->fs_info->transaction_blocked_wait);
1281
1282 spin_lock(&root->fs_info->trans_lock);
1283 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1284 prev_trans = list_entry(cur_trans->list.prev,
1285 struct btrfs_transaction, list);
1286 if (!prev_trans->commit_done) {
1287 atomic_inc(&prev_trans->use_count);
1288 spin_unlock(&root->fs_info->trans_lock);
1289
1290 wait_for_commit(root, prev_trans);
1291
1292 put_transaction(prev_trans);
1293 } else {
1294 spin_unlock(&root->fs_info->trans_lock);
1295 }
1296 } else {
1297 spin_unlock(&root->fs_info->trans_lock);
1298 }
1299
1300 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1301 should_grow = 1;
1302
1303 do {
1304 int snap_pending = 0;
1305
1306 joined = cur_trans->num_joined;
1307 if (!list_empty(&trans->transaction->pending_snapshots))
1308 snap_pending = 1;
1309
1310 WARN_ON(cur_trans != trans->transaction);
1311
1312 if (flush_on_commit || snap_pending) {
1313 btrfs_start_delalloc_inodes(root, 1);
1314 btrfs_wait_ordered_extents(root, 0, 1);
1315 }
1316
1317 ret = btrfs_run_delayed_items(trans, root);
1318 if (ret)
1319 goto cleanup_transaction;
1320
1321 /*
1322 * rename don't use btrfs_join_transaction, so, once we
1323 * set the transaction to blocked above, we aren't going
1324 * to get any new ordered operations. We can safely run
1325 * it here and no for sure that nothing new will be added
1326 * to the list
1327 */
1328 btrfs_run_ordered_operations(root, 1);
1329
1330 prepare_to_wait(&cur_trans->writer_wait, &wait,
1331 TASK_UNINTERRUPTIBLE);
1332
1333 if (atomic_read(&cur_trans->num_writers) > 1)
1334 schedule_timeout(MAX_SCHEDULE_TIMEOUT);
1335 else if (should_grow)
1336 schedule_timeout(1);
1337
1338 finish_wait(&cur_trans->writer_wait, &wait);
1339 } while (atomic_read(&cur_trans->num_writers) > 1 ||
1340 (should_grow && cur_trans->num_joined != joined));
1341
1342 /*
1343 * Ok now we need to make sure to block out any other joins while we
1344 * commit the transaction. We could have started a join before setting
1345 * no_join so make sure to wait for num_writers to == 1 again.
1346 */
1347 spin_lock(&root->fs_info->trans_lock);
1348 root->fs_info->trans_no_join = 1;
1349 spin_unlock(&root->fs_info->trans_lock);
1350 wait_event(cur_trans->writer_wait,
1351 atomic_read(&cur_trans->num_writers) == 1);
1352
1353 /*
1354 * the reloc mutex makes sure that we stop
1355 * the balancing code from coming in and moving
1356 * extents around in the middle of the commit
1357 */
1358 mutex_lock(&root->fs_info->reloc_mutex);
1359
1360 ret = btrfs_run_delayed_items(trans, root);
1361 if (ret) {
1362 mutex_unlock(&root->fs_info->reloc_mutex);
1363 goto cleanup_transaction;
1364 }
1365
1366 ret = create_pending_snapshots(trans, root->fs_info);
1367 if (ret) {
1368 mutex_unlock(&root->fs_info->reloc_mutex);
1369 goto cleanup_transaction;
1370 }
1371
1372 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1373 if (ret) {
1374 mutex_unlock(&root->fs_info->reloc_mutex);
1375 goto cleanup_transaction;
1376 }
1377
1378 /*
1379 * make sure none of the code above managed to slip in a
1380 * delayed item
1381 */
1382 btrfs_assert_delayed_root_empty(root);
1383
1384 WARN_ON(cur_trans != trans->transaction);
1385
1386 btrfs_scrub_pause(root);
1387 /* btrfs_commit_tree_roots is responsible for getting the
1388 * various roots consistent with each other. Every pointer
1389 * in the tree of tree roots has to point to the most up to date
1390 * root for every subvolume and other tree. So, we have to keep
1391 * the tree logging code from jumping in and changing any
1392 * of the trees.
1393 *
1394 * At this point in the commit, there can't be any tree-log
1395 * writers, but a little lower down we drop the trans mutex
1396 * and let new people in. By holding the tree_log_mutex
1397 * from now until after the super is written, we avoid races
1398 * with the tree-log code.
1399 */
1400 mutex_lock(&root->fs_info->tree_log_mutex);
1401
1402 ret = commit_fs_roots(trans, root);
1403 if (ret) {
1404 mutex_unlock(&root->fs_info->tree_log_mutex);
1405 mutex_unlock(&root->fs_info->reloc_mutex);
1406 goto cleanup_transaction;
1407 }
1408
1409 /* commit_fs_roots gets rid of all the tree log roots, it is now
1410 * safe to free the root of tree log roots
1411 */
1412 btrfs_free_log_root_tree(trans, root->fs_info);
1413
1414 ret = commit_cowonly_roots(trans, root);
1415 if (ret) {
1416 mutex_unlock(&root->fs_info->tree_log_mutex);
1417 mutex_unlock(&root->fs_info->reloc_mutex);
1418 goto cleanup_transaction;
1419 }
1420
1421 btrfs_prepare_extent_commit(trans, root);
1422
1423 cur_trans = root->fs_info->running_transaction;
1424
1425 btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1426 root->fs_info->tree_root->node);
1427 switch_commit_root(root->fs_info->tree_root);
1428
1429 btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1430 root->fs_info->chunk_root->node);
1431 switch_commit_root(root->fs_info->chunk_root);
1432
1433 update_super_roots(root);
1434
1435 if (!root->fs_info->log_root_recovering) {
1436 btrfs_set_super_log_root(root->fs_info->super_copy, 0);
1437 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1438 }
1439
1440 memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
1441 sizeof(*root->fs_info->super_copy));
1442
1443 trans->transaction->blocked = 0;
1444 spin_lock(&root->fs_info->trans_lock);
1445 root->fs_info->running_transaction = NULL;
1446 root->fs_info->trans_no_join = 0;
1447 spin_unlock(&root->fs_info->trans_lock);
1448 mutex_unlock(&root->fs_info->reloc_mutex);
1449
1450 wake_up(&root->fs_info->transaction_wait);
1451
1452 ret = btrfs_write_and_wait_transaction(trans, root);
1453 if (ret) {
1454 btrfs_error(root->fs_info, ret,
1455 "Error while writing out transaction.");
1456 mutex_unlock(&root->fs_info->tree_log_mutex);
1457 goto cleanup_transaction;
1458 }
1459
1460 ret = write_ctree_super(trans, root, 0);
1461 if (ret) {
1462 mutex_unlock(&root->fs_info->tree_log_mutex);
1463 goto cleanup_transaction;
1464 }
1465
1466 /*
1467 * the super is written, we can safely allow the tree-loggers
1468 * to go about their business
1469 */
1470 mutex_unlock(&root->fs_info->tree_log_mutex);
1471
1472 btrfs_finish_extent_commit(trans, root);
1473
1474 cur_trans->commit_done = 1;
1475
1476 root->fs_info->last_trans_committed = cur_trans->transid;
1477
1478 wake_up(&cur_trans->commit_wait);
1479
1480 spin_lock(&root->fs_info->trans_lock);
1481 list_del_init(&cur_trans->list);
1482 spin_unlock(&root->fs_info->trans_lock);
1483
1484 put_transaction(cur_trans);
1485 put_transaction(cur_trans);
1486
1487 trace_btrfs_transaction_commit(root);
1488
1489 btrfs_scrub_continue(root);
1490
1491 if (current->journal_info == trans)
1492 current->journal_info = NULL;
1493
1494 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1495
1496 if (current != root->fs_info->transaction_kthread)
1497 btrfs_run_delayed_iputs(root);
1498
1499 return ret;
1500
1501 cleanup_transaction:
1502 btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
1503 // WARN_ON(1);
1504 if (current->journal_info == trans)
1505 current->journal_info = NULL;
1506 cleanup_transaction(trans, root);
1507
1508 return ret;
1509 }
1510
1511 /*
1512 * interface function to delete all the snapshots we have scheduled for deletion
1513 */
btrfs_clean_old_snapshots(struct btrfs_root * root)1514 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1515 {
1516 LIST_HEAD(list);
1517 struct btrfs_fs_info *fs_info = root->fs_info;
1518
1519 spin_lock(&fs_info->trans_lock);
1520 list_splice_init(&fs_info->dead_roots, &list);
1521 spin_unlock(&fs_info->trans_lock);
1522
1523 while (!list_empty(&list)) {
1524 int ret;
1525
1526 root = list_entry(list.next, struct btrfs_root, root_list);
1527 list_del(&root->root_list);
1528
1529 btrfs_kill_all_delayed_nodes(root);
1530
1531 if (btrfs_header_backref_rev(root->node) <
1532 BTRFS_MIXED_BACKREF_REV)
1533 ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1534 else
1535 ret =btrfs_drop_snapshot(root, NULL, 1, 0);
1536 BUG_ON(ret < 0);
1537 }
1538 return 0;
1539 }
1540