8da29e8e4de15999397f137825bb378c2e983ede
[~shefty/rdma-dev.git] / fs / btrfs / transaction.c
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
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
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  */
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                         return cur_trans->aborted;
78                 atomic_inc(&cur_trans->use_count);
79                 atomic_inc(&cur_trans->num_writers);
80                 cur_trans->num_joined++;
81                 spin_unlock(&root->fs_info->trans_lock);
82                 return 0;
83         }
84         spin_unlock(&root->fs_info->trans_lock);
85
86         cur_trans = kmem_cache_alloc(btrfs_transaction_cachep, GFP_NOFS);
87         if (!cur_trans)
88                 return -ENOMEM;
89
90         spin_lock(&root->fs_info->trans_lock);
91         if (root->fs_info->running_transaction) {
92                 /*
93                  * someone started a transaction after we unlocked.  Make sure
94                  * to redo the trans_no_join checks above
95                  */
96                 kmem_cache_free(btrfs_transaction_cachep, cur_trans);
97                 cur_trans = root->fs_info->running_transaction;
98                 goto loop;
99         }
100
101         atomic_set(&cur_trans->num_writers, 1);
102         cur_trans->num_joined = 0;
103         init_waitqueue_head(&cur_trans->writer_wait);
104         init_waitqueue_head(&cur_trans->commit_wait);
105         cur_trans->in_commit = 0;
106         cur_trans->blocked = 0;
107         /*
108          * One for this trans handle, one so it will live on until we
109          * commit the transaction.
110          */
111         atomic_set(&cur_trans->use_count, 2);
112         cur_trans->commit_done = 0;
113         cur_trans->start_time = get_seconds();
114
115         cur_trans->delayed_refs.root = RB_ROOT;
116         cur_trans->delayed_refs.num_entries = 0;
117         cur_trans->delayed_refs.num_heads_ready = 0;
118         cur_trans->delayed_refs.num_heads = 0;
119         cur_trans->delayed_refs.flushing = 0;
120         cur_trans->delayed_refs.run_delayed_start = 0;
121         cur_trans->delayed_refs.seq = 1;
122         init_waitqueue_head(&cur_trans->delayed_refs.seq_wait);
123         spin_lock_init(&cur_trans->commit_lock);
124         spin_lock_init(&cur_trans->delayed_refs.lock);
125         INIT_LIST_HEAD(&cur_trans->delayed_refs.seq_head);
126
127         INIT_LIST_HEAD(&cur_trans->pending_snapshots);
128         list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
129         extent_io_tree_init(&cur_trans->dirty_pages,
130                              root->fs_info->btree_inode->i_mapping);
131         root->fs_info->generation++;
132         cur_trans->transid = root->fs_info->generation;
133         root->fs_info->running_transaction = cur_trans;
134         cur_trans->aborted = 0;
135         spin_unlock(&root->fs_info->trans_lock);
136
137         return 0;
138 }
139
140 /*
141  * this does all the record keeping required to make sure that a reference
142  * counted root is properly recorded in a given transaction.  This is required
143  * to make sure the old root from before we joined the transaction is deleted
144  * when the transaction commits
145  */
146 static int record_root_in_trans(struct btrfs_trans_handle *trans,
147                                struct btrfs_root *root)
148 {
149         if (root->ref_cows && root->last_trans < trans->transid) {
150                 WARN_ON(root == root->fs_info->extent_root);
151                 WARN_ON(root->commit_root != root->node);
152
153                 /*
154                  * see below for in_trans_setup usage rules
155                  * we have the reloc mutex held now, so there
156                  * is only one writer in this function
157                  */
158                 root->in_trans_setup = 1;
159
160                 /* make sure readers find in_trans_setup before
161                  * they find our root->last_trans update
162                  */
163                 smp_wmb();
164
165                 spin_lock(&root->fs_info->fs_roots_radix_lock);
166                 if (root->last_trans == trans->transid) {
167                         spin_unlock(&root->fs_info->fs_roots_radix_lock);
168                         return 0;
169                 }
170                 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
171                            (unsigned long)root->root_key.objectid,
172                            BTRFS_ROOT_TRANS_TAG);
173                 spin_unlock(&root->fs_info->fs_roots_radix_lock);
174                 root->last_trans = trans->transid;
175
176                 /* this is pretty tricky.  We don't want to
177                  * take the relocation lock in btrfs_record_root_in_trans
178                  * unless we're really doing the first setup for this root in
179                  * this transaction.
180                  *
181                  * Normally we'd use root->last_trans as a flag to decide
182                  * if we want to take the expensive mutex.
183                  *
184                  * But, we have to set root->last_trans before we
185                  * init the relocation root, otherwise, we trip over warnings
186                  * in ctree.c.  The solution used here is to flag ourselves
187                  * with root->in_trans_setup.  When this is 1, we're still
188                  * fixing up the reloc trees and everyone must wait.
189                  *
190                  * When this is zero, they can trust root->last_trans and fly
191                  * through btrfs_record_root_in_trans without having to take the
192                  * lock.  smp_wmb() makes sure that all the writes above are
193                  * done before we pop in the zero below
194                  */
195                 btrfs_init_reloc_root(trans, root);
196                 smp_wmb();
197                 root->in_trans_setup = 0;
198         }
199         return 0;
200 }
201
202
203 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
204                                struct btrfs_root *root)
205 {
206         if (!root->ref_cows)
207                 return 0;
208
209         /*
210          * see record_root_in_trans for comments about in_trans_setup usage
211          * and barriers
212          */
213         smp_rmb();
214         if (root->last_trans == trans->transid &&
215             !root->in_trans_setup)
216                 return 0;
217
218         mutex_lock(&root->fs_info->reloc_mutex);
219         record_root_in_trans(trans, root);
220         mutex_unlock(&root->fs_info->reloc_mutex);
221
222         return 0;
223 }
224
225 /* wait for commit against the current transaction to become unblocked
226  * when this is done, it is safe to start a new transaction, but the current
227  * transaction might not be fully on disk.
228  */
229 static void wait_current_trans(struct btrfs_root *root)
230 {
231         struct btrfs_transaction *cur_trans;
232
233         spin_lock(&root->fs_info->trans_lock);
234         cur_trans = root->fs_info->running_transaction;
235         if (cur_trans && cur_trans->blocked) {
236                 atomic_inc(&cur_trans->use_count);
237                 spin_unlock(&root->fs_info->trans_lock);
238
239                 wait_event(root->fs_info->transaction_wait,
240                            !cur_trans->blocked);
241                 put_transaction(cur_trans);
242         } else {
243                 spin_unlock(&root->fs_info->trans_lock);
244         }
245 }
246
247 enum btrfs_trans_type {
248         TRANS_START,
249         TRANS_JOIN,
250         TRANS_USERSPACE,
251         TRANS_JOIN_NOLOCK,
252 };
253
254 static int may_wait_transaction(struct btrfs_root *root, int type)
255 {
256         if (root->fs_info->log_root_recovering)
257                 return 0;
258
259         if (type == TRANS_USERSPACE)
260                 return 1;
261
262         if (type == TRANS_START &&
263             !atomic_read(&root->fs_info->open_ioctl_trans))
264                 return 1;
265
266         return 0;
267 }
268
269 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
270                                                     u64 num_items, int type)
271 {
272         struct btrfs_trans_handle *h;
273         struct btrfs_transaction *cur_trans;
274         u64 num_bytes = 0;
275         int ret;
276
277         if (root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR)
278                 return ERR_PTR(-EROFS);
279
280         if (current->journal_info) {
281                 WARN_ON(type != TRANS_JOIN && type != TRANS_JOIN_NOLOCK);
282                 h = current->journal_info;
283                 h->use_count++;
284                 h->orig_rsv = h->block_rsv;
285                 h->block_rsv = NULL;
286                 goto got_it;
287         }
288
289         /*
290          * Do the reservation before we join the transaction so we can do all
291          * the appropriate flushing if need be.
292          */
293         if (num_items > 0 && root != root->fs_info->chunk_root) {
294                 num_bytes = btrfs_calc_trans_metadata_size(root, num_items);
295                 ret = btrfs_block_rsv_add(root,
296                                           &root->fs_info->trans_block_rsv,
297                                           num_bytes);
298                 if (ret)
299                         return ERR_PTR(ret);
300         }
301 again:
302         h = kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
303         if (!h)
304                 return ERR_PTR(-ENOMEM);
305
306         if (may_wait_transaction(root, type))
307                 wait_current_trans(root);
308
309         do {
310                 ret = join_transaction(root, type == TRANS_JOIN_NOLOCK);
311                 if (ret == -EBUSY)
312                         wait_current_trans(root);
313         } while (ret == -EBUSY);
314
315         if (ret < 0) {
316                 kmem_cache_free(btrfs_trans_handle_cachep, h);
317                 return ERR_PTR(ret);
318         }
319
320         cur_trans = root->fs_info->running_transaction;
321
322         h->transid = cur_trans->transid;
323         h->transaction = cur_trans;
324         h->blocks_used = 0;
325         h->bytes_reserved = 0;
326         h->delayed_ref_updates = 0;
327         h->use_count = 1;
328         h->block_rsv = NULL;
329         h->orig_rsv = NULL;
330         h->aborted = 0;
331
332         smp_mb();
333         if (cur_trans->blocked && may_wait_transaction(root, type)) {
334                 btrfs_commit_transaction(h, root);
335                 goto again;
336         }
337
338         if (num_bytes) {
339                 trace_btrfs_space_reservation(root->fs_info, "transaction",
340                                               h->transid, num_bytes, 1);
341                 h->block_rsv = &root->fs_info->trans_block_rsv;
342                 h->bytes_reserved = num_bytes;
343         }
344
345 got_it:
346         btrfs_record_root_in_trans(h, root);
347
348         if (!current->journal_info && type != TRANS_USERSPACE)
349                 current->journal_info = h;
350         return h;
351 }
352
353 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
354                                                    int num_items)
355 {
356         return start_transaction(root, num_items, TRANS_START);
357 }
358 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root)
359 {
360         return start_transaction(root, 0, TRANS_JOIN);
361 }
362
363 struct btrfs_trans_handle *btrfs_join_transaction_nolock(struct btrfs_root *root)
364 {
365         return start_transaction(root, 0, TRANS_JOIN_NOLOCK);
366 }
367
368 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *root)
369 {
370         return start_transaction(root, 0, TRANS_USERSPACE);
371 }
372
373 /* wait for a transaction commit to be fully complete */
374 static noinline void wait_for_commit(struct btrfs_root *root,
375                                     struct btrfs_transaction *commit)
376 {
377         wait_event(commit->commit_wait, commit->commit_done);
378 }
379
380 int btrfs_wait_for_commit(struct btrfs_root *root, u64 transid)
381 {
382         struct btrfs_transaction *cur_trans = NULL, *t;
383         int ret;
384
385         ret = 0;
386         if (transid) {
387                 if (transid <= root->fs_info->last_trans_committed)
388                         goto out;
389
390                 /* find specified transaction */
391                 spin_lock(&root->fs_info->trans_lock);
392                 list_for_each_entry(t, &root->fs_info->trans_list, list) {
393                         if (t->transid == transid) {
394                                 cur_trans = t;
395                                 atomic_inc(&cur_trans->use_count);
396                                 break;
397                         }
398                         if (t->transid > transid)
399                                 break;
400                 }
401                 spin_unlock(&root->fs_info->trans_lock);
402                 ret = -EINVAL;
403                 if (!cur_trans)
404                         goto out;  /* bad transid */
405         } else {
406                 /* find newest transaction that is committing | committed */
407                 spin_lock(&root->fs_info->trans_lock);
408                 list_for_each_entry_reverse(t, &root->fs_info->trans_list,
409                                             list) {
410                         if (t->in_commit) {
411                                 if (t->commit_done)
412                                         break;
413                                 cur_trans = t;
414                                 atomic_inc(&cur_trans->use_count);
415                                 break;
416                         }
417                 }
418                 spin_unlock(&root->fs_info->trans_lock);
419                 if (!cur_trans)
420                         goto out;  /* nothing committing|committed */
421         }
422
423         wait_for_commit(root, cur_trans);
424
425         put_transaction(cur_trans);
426         ret = 0;
427 out:
428         return ret;
429 }
430
431 void btrfs_throttle(struct btrfs_root *root)
432 {
433         if (!atomic_read(&root->fs_info->open_ioctl_trans))
434                 wait_current_trans(root);
435 }
436
437 static int should_end_transaction(struct btrfs_trans_handle *trans,
438                                   struct btrfs_root *root)
439 {
440         int ret;
441
442         ret = btrfs_block_rsv_check(root, &root->fs_info->global_block_rsv, 5);
443         return ret ? 1 : 0;
444 }
445
446 int btrfs_should_end_transaction(struct btrfs_trans_handle *trans,
447                                  struct btrfs_root *root)
448 {
449         struct btrfs_transaction *cur_trans = trans->transaction;
450         struct btrfs_block_rsv *rsv = trans->block_rsv;
451         int updates;
452         int err;
453
454         smp_mb();
455         if (cur_trans->blocked || cur_trans->delayed_refs.flushing)
456                 return 1;
457
458         /*
459          * We need to do this in case we're deleting csums so the global block
460          * rsv get's used instead of the csum block rsv.
461          */
462         trans->block_rsv = NULL;
463
464         updates = trans->delayed_ref_updates;
465         trans->delayed_ref_updates = 0;
466         if (updates) {
467                 err = btrfs_run_delayed_refs(trans, root, updates);
468                 if (err) /* Error code will also eval true */
469                         return err;
470         }
471
472         trans->block_rsv = rsv;
473
474         return should_end_transaction(trans, root);
475 }
476
477 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
478                           struct btrfs_root *root, int throttle, int lock)
479 {
480         struct btrfs_transaction *cur_trans = trans->transaction;
481         struct btrfs_fs_info *info = root->fs_info;
482         int count = 0;
483
484         if (--trans->use_count) {
485                 trans->block_rsv = trans->orig_rsv;
486                 return 0;
487         }
488
489         btrfs_trans_release_metadata(trans, root);
490         trans->block_rsv = NULL;
491         while (count < 2) {
492                 unsigned long cur = trans->delayed_ref_updates;
493                 trans->delayed_ref_updates = 0;
494                 if (cur &&
495                     trans->transaction->delayed_refs.num_heads_ready > 64) {
496                         trans->delayed_ref_updates = 0;
497                         btrfs_run_delayed_refs(trans, root, cur);
498                 } else {
499                         break;
500                 }
501                 count++;
502         }
503
504         if (lock && !atomic_read(&root->fs_info->open_ioctl_trans) &&
505             should_end_transaction(trans, root)) {
506                 trans->transaction->blocked = 1;
507                 smp_wmb();
508         }
509
510         if (lock && cur_trans->blocked && !cur_trans->in_commit) {
511                 if (throttle) {
512                         /*
513                          * We may race with somebody else here so end up having
514                          * to call end_transaction on ourselves again, so inc
515                          * our use_count.
516                          */
517                         trans->use_count++;
518                         return btrfs_commit_transaction(trans, root);
519                 } else {
520                         wake_up_process(info->transaction_kthread);
521                 }
522         }
523
524         WARN_ON(cur_trans != info->running_transaction);
525         WARN_ON(atomic_read(&cur_trans->num_writers) < 1);
526         atomic_dec(&cur_trans->num_writers);
527
528         smp_mb();
529         if (waitqueue_active(&cur_trans->writer_wait))
530                 wake_up(&cur_trans->writer_wait);
531         put_transaction(cur_trans);
532
533         if (current->journal_info == trans)
534                 current->journal_info = NULL;
535         memset(trans, 0, sizeof(*trans));
536         kmem_cache_free(btrfs_trans_handle_cachep, trans);
537
538         if (throttle)
539                 btrfs_run_delayed_iputs(root);
540
541         if (trans->aborted ||
542             root->fs_info->fs_state & BTRFS_SUPER_FLAG_ERROR) {
543                 return -EIO;
544         }
545
546         return 0;
547 }
548
549 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
550                           struct btrfs_root *root)
551 {
552         int ret;
553
554         ret = __btrfs_end_transaction(trans, root, 0, 1);
555         if (ret)
556                 return ret;
557         return 0;
558 }
559
560 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
561                                    struct btrfs_root *root)
562 {
563         int ret;
564
565         ret = __btrfs_end_transaction(trans, root, 1, 1);
566         if (ret)
567                 return ret;
568         return 0;
569 }
570
571 int btrfs_end_transaction_nolock(struct btrfs_trans_handle *trans,
572                                  struct btrfs_root *root)
573 {
574         int ret;
575
576         ret = __btrfs_end_transaction(trans, root, 0, 0);
577         if (ret)
578                 return ret;
579         return 0;
580 }
581
582 int btrfs_end_transaction_dmeta(struct btrfs_trans_handle *trans,
583                                 struct btrfs_root *root)
584 {
585         return __btrfs_end_transaction(trans, root, 1, 1);
586 }
587
588 /*
589  * when btree blocks are allocated, they have some corresponding bits set for
590  * them in one of two extent_io trees.  This is used to make sure all of
591  * those extents are sent to disk but does not wait on them
592  */
593 int btrfs_write_marked_extents(struct btrfs_root *root,
594                                struct extent_io_tree *dirty_pages, int mark)
595 {
596         int err = 0;
597         int werr = 0;
598         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
599         u64 start = 0;
600         u64 end;
601
602         while (!find_first_extent_bit(dirty_pages, start, &start, &end,
603                                       mark)) {
604                 convert_extent_bit(dirty_pages, start, end, EXTENT_NEED_WAIT, mark,
605                                    GFP_NOFS);
606                 err = filemap_fdatawrite_range(mapping, start, end);
607                 if (err)
608                         werr = err;
609                 cond_resched();
610                 start = end + 1;
611         }
612         if (err)
613                 werr = err;
614         return werr;
615 }
616
617 /*
618  * when btree blocks are allocated, they have some corresponding bits set for
619  * them in one of two extent_io trees.  This is used to make sure all of
620  * those extents are on disk for transaction or log commit.  We wait
621  * on all the pages and clear them from the dirty pages state tree
622  */
623 int btrfs_wait_marked_extents(struct btrfs_root *root,
624                               struct extent_io_tree *dirty_pages, int mark)
625 {
626         int err = 0;
627         int werr = 0;
628         struct address_space *mapping = root->fs_info->btree_inode->i_mapping;
629         u64 start = 0;
630         u64 end;
631
632         while (!find_first_extent_bit(dirty_pages, start, &start, &end,
633                                       EXTENT_NEED_WAIT)) {
634                 clear_extent_bits(dirty_pages, start, end, EXTENT_NEED_WAIT, GFP_NOFS);
635                 err = filemap_fdatawait_range(mapping, start, end);
636                 if (err)
637                         werr = err;
638                 cond_resched();
639                 start = end + 1;
640         }
641         if (err)
642                 werr = err;
643         return werr;
644 }
645
646 /*
647  * when btree blocks are allocated, they have some corresponding bits set for
648  * them in one of two extent_io trees.  This is used to make sure all of
649  * those extents are on disk for transaction or log commit
650  */
651 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
652                                 struct extent_io_tree *dirty_pages, int mark)
653 {
654         int ret;
655         int ret2;
656
657         ret = btrfs_write_marked_extents(root, dirty_pages, mark);
658         ret2 = btrfs_wait_marked_extents(root, dirty_pages, mark);
659
660         if (ret)
661                 return ret;
662         if (ret2)
663                 return ret2;
664         return 0;
665 }
666
667 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
668                                      struct btrfs_root *root)
669 {
670         if (!trans || !trans->transaction) {
671                 struct inode *btree_inode;
672                 btree_inode = root->fs_info->btree_inode;
673                 return filemap_write_and_wait(btree_inode->i_mapping);
674         }
675         return btrfs_write_and_wait_marked_extents(root,
676                                            &trans->transaction->dirty_pages,
677                                            EXTENT_DIRTY);
678 }
679
680 /*
681  * this is used to update the root pointer in the tree of tree roots.
682  *
683  * But, in the case of the extent allocation tree, updating the root
684  * pointer may allocate blocks which may change the root of the extent
685  * allocation tree.
686  *
687  * So, this loops and repeats and makes sure the cowonly root didn't
688  * change while the root pointer was being updated in the metadata.
689  */
690 static int update_cowonly_root(struct btrfs_trans_handle *trans,
691                                struct btrfs_root *root)
692 {
693         int ret;
694         u64 old_root_bytenr;
695         u64 old_root_used;
696         struct btrfs_root *tree_root = root->fs_info->tree_root;
697
698         old_root_used = btrfs_root_used(&root->root_item);
699         btrfs_write_dirty_block_groups(trans, root);
700
701         while (1) {
702                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
703                 if (old_root_bytenr == root->node->start &&
704                     old_root_used == btrfs_root_used(&root->root_item))
705                         break;
706
707                 btrfs_set_root_node(&root->root_item, root->node);
708                 ret = btrfs_update_root(trans, tree_root,
709                                         &root->root_key,
710                                         &root->root_item);
711                 if (ret)
712                         return ret;
713
714                 old_root_used = btrfs_root_used(&root->root_item);
715                 ret = btrfs_write_dirty_block_groups(trans, root);
716                 if (ret)
717                         return ret;
718         }
719
720         if (root != root->fs_info->extent_root)
721                 switch_commit_root(root);
722
723         return 0;
724 }
725
726 /*
727  * update all the cowonly tree roots on disk
728  *
729  * The error handling in this function may not be obvious. Any of the
730  * failures will cause the file system to go offline. We still need
731  * to clean up the delayed refs.
732  */
733 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
734                                          struct btrfs_root *root)
735 {
736         struct btrfs_fs_info *fs_info = root->fs_info;
737         struct list_head *next;
738         struct extent_buffer *eb;
739         int ret;
740
741         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
742         if (ret)
743                 return ret;
744
745         eb = btrfs_lock_root_node(fs_info->tree_root);
746         ret = btrfs_cow_block(trans, fs_info->tree_root, eb, NULL,
747                               0, &eb);
748         btrfs_tree_unlock(eb);
749         free_extent_buffer(eb);
750
751         if (ret)
752                 return ret;
753
754         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
755         if (ret)
756                 return ret;
757
758         while (!list_empty(&fs_info->dirty_cowonly_roots)) {
759                 next = fs_info->dirty_cowonly_roots.next;
760                 list_del_init(next);
761                 root = list_entry(next, struct btrfs_root, dirty_list);
762
763                 ret = update_cowonly_root(trans, root);
764                 if (ret)
765                         return ret;
766         }
767
768         down_write(&fs_info->extent_commit_sem);
769         switch_commit_root(fs_info->extent_root);
770         up_write(&fs_info->extent_commit_sem);
771
772         return 0;
773 }
774
775 /*
776  * dead roots are old snapshots that need to be deleted.  This allocates
777  * a dirty root struct and adds it into the list of dead roots that need to
778  * be deleted
779  */
780 int btrfs_add_dead_root(struct btrfs_root *root)
781 {
782         spin_lock(&root->fs_info->trans_lock);
783         list_add(&root->root_list, &root->fs_info->dead_roots);
784         spin_unlock(&root->fs_info->trans_lock);
785         return 0;
786 }
787
788 /*
789  * update all the cowonly tree roots on disk
790  */
791 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
792                                     struct btrfs_root *root)
793 {
794         struct btrfs_root *gang[8];
795         struct btrfs_fs_info *fs_info = root->fs_info;
796         int i;
797         int ret;
798         int err = 0;
799
800         spin_lock(&fs_info->fs_roots_radix_lock);
801         while (1) {
802                 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
803                                                  (void **)gang, 0,
804                                                  ARRAY_SIZE(gang),
805                                                  BTRFS_ROOT_TRANS_TAG);
806                 if (ret == 0)
807                         break;
808                 for (i = 0; i < ret; i++) {
809                         root = gang[i];
810                         radix_tree_tag_clear(&fs_info->fs_roots_radix,
811                                         (unsigned long)root->root_key.objectid,
812                                         BTRFS_ROOT_TRANS_TAG);
813                         spin_unlock(&fs_info->fs_roots_radix_lock);
814
815                         btrfs_free_log(trans, root);
816                         btrfs_update_reloc_root(trans, root);
817                         btrfs_orphan_commit_root(trans, root);
818
819                         btrfs_save_ino_cache(root, trans);
820
821                         /* see comments in should_cow_block() */
822                         root->force_cow = 0;
823                         smp_wmb();
824
825                         if (root->commit_root != root->node) {
826                                 mutex_lock(&root->fs_commit_mutex);
827                                 switch_commit_root(root);
828                                 btrfs_unpin_free_ino(root);
829                                 mutex_unlock(&root->fs_commit_mutex);
830
831                                 btrfs_set_root_node(&root->root_item,
832                                                     root->node);
833                         }
834
835                         err = btrfs_update_root(trans, fs_info->tree_root,
836                                                 &root->root_key,
837                                                 &root->root_item);
838                         spin_lock(&fs_info->fs_roots_radix_lock);
839                         if (err)
840                                 break;
841                 }
842         }
843         spin_unlock(&fs_info->fs_roots_radix_lock);
844         return err;
845 }
846
847 /*
848  * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
849  * otherwise every leaf in the btree is read and defragged.
850  */
851 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
852 {
853         struct btrfs_fs_info *info = root->fs_info;
854         struct btrfs_trans_handle *trans;
855         int ret;
856         unsigned long nr;
857
858         if (xchg(&root->defrag_running, 1))
859                 return 0;
860
861         while (1) {
862                 trans = btrfs_start_transaction(root, 0);
863                 if (IS_ERR(trans))
864                         return PTR_ERR(trans);
865
866                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
867
868                 nr = trans->blocks_used;
869                 btrfs_end_transaction(trans, root);
870                 btrfs_btree_balance_dirty(info->tree_root, nr);
871                 cond_resched();
872
873                 if (btrfs_fs_closing(root->fs_info) || ret != -EAGAIN)
874                         break;
875         }
876         root->defrag_running = 0;
877         return ret;
878 }
879
880 /*
881  * new snapshots need to be created at a very specific time in the
882  * transaction commit.  This does the actual creation
883  */
884 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
885                                    struct btrfs_fs_info *fs_info,
886                                    struct btrfs_pending_snapshot *pending)
887 {
888         struct btrfs_key key;
889         struct btrfs_root_item *new_root_item;
890         struct btrfs_root *tree_root = fs_info->tree_root;
891         struct btrfs_root *root = pending->root;
892         struct btrfs_root *parent_root;
893         struct btrfs_block_rsv *rsv;
894         struct inode *parent_inode;
895         struct dentry *parent;
896         struct dentry *dentry;
897         struct extent_buffer *tmp;
898         struct extent_buffer *old;
899         int ret;
900         u64 to_reserve = 0;
901         u64 index = 0;
902         u64 objectid;
903         u64 root_flags;
904
905         rsv = trans->block_rsv;
906
907         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
908         if (!new_root_item) {
909                 ret = pending->error = -ENOMEM;
910                 goto fail;
911         }
912
913         ret = btrfs_find_free_objectid(tree_root, &objectid);
914         if (ret) {
915                 pending->error = ret;
916                 goto fail;
917         }
918
919         btrfs_reloc_pre_snapshot(trans, pending, &to_reserve);
920
921         if (to_reserve > 0) {
922                 ret = btrfs_block_rsv_add_noflush(root, &pending->block_rsv,
923                                                   to_reserve);
924                 if (ret) {
925                         pending->error = ret;
926                         goto fail;
927                 }
928         }
929
930         key.objectid = objectid;
931         key.offset = (u64)-1;
932         key.type = BTRFS_ROOT_ITEM_KEY;
933
934         trans->block_rsv = &pending->block_rsv;
935
936         dentry = pending->dentry;
937         parent = dget_parent(dentry);
938         parent_inode = parent->d_inode;
939         parent_root = BTRFS_I(parent_inode)->root;
940         record_root_in_trans(trans, parent_root);
941
942         /*
943          * insert the directory item
944          */
945         ret = btrfs_set_inode_index(parent_inode, &index);
946         BUG_ON(ret); /* -ENOMEM */
947         ret = btrfs_insert_dir_item(trans, parent_root,
948                                 dentry->d_name.name, dentry->d_name.len,
949                                 parent_inode, &key,
950                                 BTRFS_FT_DIR, index);
951         if (ret == -EEXIST) {
952                 pending->error = -EEXIST;
953                 dput(parent);
954                 goto fail;
955         } else if (ret) {
956                 goto abort_trans_dput;
957         }
958
959         btrfs_i_size_write(parent_inode, parent_inode->i_size +
960                                          dentry->d_name.len * 2);
961         ret = btrfs_update_inode(trans, parent_root, parent_inode);
962         if (ret)
963                 goto abort_trans_dput;
964
965         /*
966          * pull in the delayed directory update
967          * and the delayed inode item
968          * otherwise we corrupt the FS during
969          * snapshot
970          */
971         ret = btrfs_run_delayed_items(trans, root);
972         if (ret) { /* Transaction aborted */
973                 dput(parent);
974                 goto fail;
975         }
976
977         record_root_in_trans(trans, root);
978         btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
979         memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
980         btrfs_check_and_init_root_item(new_root_item);
981
982         root_flags = btrfs_root_flags(new_root_item);
983         if (pending->readonly)
984                 root_flags |= BTRFS_ROOT_SUBVOL_RDONLY;
985         else
986                 root_flags &= ~BTRFS_ROOT_SUBVOL_RDONLY;
987         btrfs_set_root_flags(new_root_item, root_flags);
988
989         old = btrfs_lock_root_node(root);
990         ret = btrfs_cow_block(trans, root, old, NULL, 0, &old);
991         if (ret) {
992                 btrfs_tree_unlock(old);
993                 free_extent_buffer(old);
994                 goto abort_trans_dput;
995         }
996
997         btrfs_set_lock_blocking(old);
998
999         ret = btrfs_copy_root(trans, root, old, &tmp, objectid);
1000         /* clean up in any case */
1001         btrfs_tree_unlock(old);
1002         free_extent_buffer(old);
1003         if (ret)
1004                 goto abort_trans_dput;
1005
1006         /* see comments in should_cow_block() */
1007         root->force_cow = 1;
1008         smp_wmb();
1009
1010         btrfs_set_root_node(new_root_item, tmp);
1011         /* record when the snapshot was created in key.offset */
1012         key.offset = trans->transid;
1013         ret = btrfs_insert_root(trans, tree_root, &key, new_root_item);
1014         btrfs_tree_unlock(tmp);
1015         free_extent_buffer(tmp);
1016         if (ret)
1017                 goto abort_trans_dput;
1018
1019         /*
1020          * insert root back/forward references
1021          */
1022         ret = btrfs_add_root_ref(trans, tree_root, objectid,
1023                                  parent_root->root_key.objectid,
1024                                  btrfs_ino(parent_inode), index,
1025                                  dentry->d_name.name, dentry->d_name.len);
1026         dput(parent);
1027         if (ret)
1028                 goto fail;
1029
1030         key.offset = (u64)-1;
1031         pending->snap = btrfs_read_fs_root_no_name(root->fs_info, &key);
1032         if (IS_ERR(pending->snap)) {
1033                 ret = PTR_ERR(pending->snap);
1034                 goto abort_trans;
1035         }
1036
1037         ret = btrfs_reloc_post_snapshot(trans, pending);
1038         if (ret)
1039                 goto abort_trans;
1040         ret = 0;
1041 fail:
1042         kfree(new_root_item);
1043         trans->block_rsv = rsv;
1044         btrfs_block_rsv_release(root, &pending->block_rsv, (u64)-1);
1045         return ret;
1046
1047 abort_trans_dput:
1048         dput(parent);
1049 abort_trans:
1050         btrfs_abort_transaction(trans, root, ret);
1051         goto fail;
1052 }
1053
1054 /*
1055  * create all the snapshots we've scheduled for creation
1056  */
1057 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
1058                                              struct btrfs_fs_info *fs_info)
1059 {
1060         struct btrfs_pending_snapshot *pending;
1061         struct list_head *head = &trans->transaction->pending_snapshots;
1062
1063         list_for_each_entry(pending, head, list)
1064                 create_pending_snapshot(trans, fs_info, pending);
1065         return 0;
1066 }
1067
1068 static void update_super_roots(struct btrfs_root *root)
1069 {
1070         struct btrfs_root_item *root_item;
1071         struct btrfs_super_block *super;
1072
1073         super = root->fs_info->super_copy;
1074
1075         root_item = &root->fs_info->chunk_root->root_item;
1076         super->chunk_root = root_item->bytenr;
1077         super->chunk_root_generation = root_item->generation;
1078         super->chunk_root_level = root_item->level;
1079
1080         root_item = &root->fs_info->tree_root->root_item;
1081         super->root = root_item->bytenr;
1082         super->generation = root_item->generation;
1083         super->root_level = root_item->level;
1084         if (btrfs_test_opt(root, SPACE_CACHE))
1085                 super->cache_generation = root_item->generation;
1086 }
1087
1088 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
1089 {
1090         int ret = 0;
1091         spin_lock(&info->trans_lock);
1092         if (info->running_transaction)
1093                 ret = info->running_transaction->in_commit;
1094         spin_unlock(&info->trans_lock);
1095         return ret;
1096 }
1097
1098 int btrfs_transaction_blocked(struct btrfs_fs_info *info)
1099 {
1100         int ret = 0;
1101         spin_lock(&info->trans_lock);
1102         if (info->running_transaction)
1103                 ret = info->running_transaction->blocked;
1104         spin_unlock(&info->trans_lock);
1105         return ret;
1106 }
1107
1108 /*
1109  * wait for the current transaction commit to start and block subsequent
1110  * transaction joins
1111  */
1112 static void wait_current_trans_commit_start(struct btrfs_root *root,
1113                                             struct btrfs_transaction *trans)
1114 {
1115         wait_event(root->fs_info->transaction_blocked_wait, trans->in_commit);
1116 }
1117
1118 /*
1119  * wait for the current transaction to start and then become unblocked.
1120  * caller holds ref.
1121  */
1122 static void wait_current_trans_commit_start_and_unblock(struct btrfs_root *root,
1123                                          struct btrfs_transaction *trans)
1124 {
1125         wait_event(root->fs_info->transaction_wait,
1126                    trans->commit_done || (trans->in_commit && !trans->blocked));
1127 }
1128
1129 /*
1130  * commit transactions asynchronously. once btrfs_commit_transaction_async
1131  * returns, any subsequent transaction will not be allowed to join.
1132  */
1133 struct btrfs_async_commit {
1134         struct btrfs_trans_handle *newtrans;
1135         struct btrfs_root *root;
1136         struct delayed_work work;
1137 };
1138
1139 static void do_async_commit(struct work_struct *work)
1140 {
1141         struct btrfs_async_commit *ac =
1142                 container_of(work, struct btrfs_async_commit, work.work);
1143
1144         btrfs_commit_transaction(ac->newtrans, ac->root);
1145         kfree(ac);
1146 }
1147
1148 int btrfs_commit_transaction_async(struct btrfs_trans_handle *trans,
1149                                    struct btrfs_root *root,
1150                                    int wait_for_unblock)
1151 {
1152         struct btrfs_async_commit *ac;
1153         struct btrfs_transaction *cur_trans;
1154
1155         ac = kmalloc(sizeof(*ac), GFP_NOFS);
1156         if (!ac)
1157                 return -ENOMEM;
1158
1159         INIT_DELAYED_WORK(&ac->work, do_async_commit);
1160         ac->root = root;
1161         ac->newtrans = btrfs_join_transaction(root);
1162         if (IS_ERR(ac->newtrans)) {
1163                 int err = PTR_ERR(ac->newtrans);
1164                 kfree(ac);
1165                 return err;
1166         }
1167
1168         /* take transaction reference */
1169         cur_trans = trans->transaction;
1170         atomic_inc(&cur_trans->use_count);
1171
1172         btrfs_end_transaction(trans, root);
1173         schedule_delayed_work(&ac->work, 0);
1174
1175         /* wait for transaction to start and unblock */
1176         if (wait_for_unblock)
1177                 wait_current_trans_commit_start_and_unblock(root, cur_trans);
1178         else
1179                 wait_current_trans_commit_start(root, cur_trans);
1180
1181         if (current->journal_info == trans)
1182                 current->journal_info = NULL;
1183
1184         put_transaction(cur_trans);
1185         return 0;
1186 }
1187
1188
1189 static void cleanup_transaction(struct btrfs_trans_handle *trans,
1190                                 struct btrfs_root *root)
1191 {
1192         struct btrfs_transaction *cur_trans = trans->transaction;
1193
1194         WARN_ON(trans->use_count > 1);
1195
1196         spin_lock(&root->fs_info->trans_lock);
1197         list_del_init(&cur_trans->list);
1198         spin_unlock(&root->fs_info->trans_lock);
1199
1200         btrfs_cleanup_one_transaction(trans->transaction, root);
1201
1202         put_transaction(cur_trans);
1203         put_transaction(cur_trans);
1204
1205         trace_btrfs_transaction_commit(root);
1206
1207         btrfs_scrub_continue(root);
1208
1209         if (current->journal_info == trans)
1210                 current->journal_info = NULL;
1211
1212         kmem_cache_free(btrfs_trans_handle_cachep, trans);
1213 }
1214
1215 /*
1216  * btrfs_transaction state sequence:
1217  *    in_commit = 0, blocked = 0  (initial)
1218  *    in_commit = 1, blocked = 1
1219  *    blocked = 0
1220  *    commit_done = 1
1221  */
1222 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
1223                              struct btrfs_root *root)
1224 {
1225         unsigned long joined = 0;
1226         struct btrfs_transaction *cur_trans = trans->transaction;
1227         struct btrfs_transaction *prev_trans = NULL;
1228         DEFINE_WAIT(wait);
1229         int ret = -EIO;
1230         int should_grow = 0;
1231         unsigned long now = get_seconds();
1232         int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
1233
1234         btrfs_run_ordered_operations(root, 0);
1235
1236         btrfs_trans_release_metadata(trans, root);
1237         trans->block_rsv = NULL;
1238
1239         if (cur_trans->aborted)
1240                 goto cleanup_transaction;
1241
1242         /* make a pass through all the delayed refs we have so far
1243          * any runnings procs may add more while we are here
1244          */
1245         ret = btrfs_run_delayed_refs(trans, root, 0);
1246         if (ret)
1247                 goto cleanup_transaction;
1248
1249         cur_trans = trans->transaction;
1250
1251         /*
1252          * set the flushing flag so procs in this transaction have to
1253          * start sending their work down.
1254          */
1255         cur_trans->delayed_refs.flushing = 1;
1256
1257         ret = btrfs_run_delayed_refs(trans, root, 0);
1258         if (ret)
1259                 goto cleanup_transaction;
1260
1261         spin_lock(&cur_trans->commit_lock);
1262         if (cur_trans->in_commit) {
1263                 spin_unlock(&cur_trans->commit_lock);
1264                 atomic_inc(&cur_trans->use_count);
1265                 ret = btrfs_end_transaction(trans, root);
1266
1267                 wait_for_commit(root, cur_trans);
1268
1269                 put_transaction(cur_trans);
1270
1271                 return ret;
1272         }
1273
1274         trans->transaction->in_commit = 1;
1275         trans->transaction->blocked = 1;
1276         spin_unlock(&cur_trans->commit_lock);
1277         wake_up(&root->fs_info->transaction_blocked_wait);
1278
1279         spin_lock(&root->fs_info->trans_lock);
1280         if (cur_trans->list.prev != &root->fs_info->trans_list) {
1281                 prev_trans = list_entry(cur_trans->list.prev,
1282                                         struct btrfs_transaction, list);
1283                 if (!prev_trans->commit_done) {
1284                         atomic_inc(&prev_trans->use_count);
1285                         spin_unlock(&root->fs_info->trans_lock);
1286
1287                         wait_for_commit(root, prev_trans);
1288
1289                         put_transaction(prev_trans);
1290                 } else {
1291                         spin_unlock(&root->fs_info->trans_lock);
1292                 }
1293         } else {
1294                 spin_unlock(&root->fs_info->trans_lock);
1295         }
1296
1297         if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1298                 should_grow = 1;
1299
1300         do {
1301                 int snap_pending = 0;
1302
1303                 joined = cur_trans->num_joined;
1304                 if (!list_empty(&trans->transaction->pending_snapshots))
1305                         snap_pending = 1;
1306
1307                 WARN_ON(cur_trans != trans->transaction);
1308
1309                 if (flush_on_commit || snap_pending) {
1310                         btrfs_start_delalloc_inodes(root, 1);
1311                         btrfs_wait_ordered_extents(root, 0, 1);
1312                 }
1313
1314                 ret = btrfs_run_delayed_items(trans, root);
1315                 if (ret)
1316                         goto cleanup_transaction;
1317
1318                 /*
1319                  * rename don't use btrfs_join_transaction, so, once we
1320                  * set the transaction to blocked above, we aren't going
1321                  * to get any new ordered operations.  We can safely run
1322                  * it here and no for sure that nothing new will be added
1323                  * to the list
1324                  */
1325                 btrfs_run_ordered_operations(root, 1);
1326
1327                 prepare_to_wait(&cur_trans->writer_wait, &wait,
1328                                 TASK_UNINTERRUPTIBLE);
1329
1330                 if (atomic_read(&cur_trans->num_writers) > 1)
1331                         schedule_timeout(MAX_SCHEDULE_TIMEOUT);
1332                 else if (should_grow)
1333                         schedule_timeout(1);
1334
1335                 finish_wait(&cur_trans->writer_wait, &wait);
1336         } while (atomic_read(&cur_trans->num_writers) > 1 ||
1337                  (should_grow && cur_trans->num_joined != joined));
1338
1339         /*
1340          * Ok now we need to make sure to block out any other joins while we
1341          * commit the transaction.  We could have started a join before setting
1342          * no_join so make sure to wait for num_writers to == 1 again.
1343          */
1344         spin_lock(&root->fs_info->trans_lock);
1345         root->fs_info->trans_no_join = 1;
1346         spin_unlock(&root->fs_info->trans_lock);
1347         wait_event(cur_trans->writer_wait,
1348                    atomic_read(&cur_trans->num_writers) == 1);
1349
1350         /*
1351          * the reloc mutex makes sure that we stop
1352          * the balancing code from coming in and moving
1353          * extents around in the middle of the commit
1354          */
1355         mutex_lock(&root->fs_info->reloc_mutex);
1356
1357         ret = btrfs_run_delayed_items(trans, root);
1358         if (ret) {
1359                 mutex_unlock(&root->fs_info->reloc_mutex);
1360                 goto cleanup_transaction;
1361         }
1362
1363         ret = create_pending_snapshots(trans, root->fs_info);
1364         if (ret) {
1365                 mutex_unlock(&root->fs_info->reloc_mutex);
1366                 goto cleanup_transaction;
1367         }
1368
1369         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1370         if (ret) {
1371                 mutex_unlock(&root->fs_info->reloc_mutex);
1372                 goto cleanup_transaction;
1373         }
1374
1375         /*
1376          * make sure none of the code above managed to slip in a
1377          * delayed item
1378          */
1379         btrfs_assert_delayed_root_empty(root);
1380
1381         WARN_ON(cur_trans != trans->transaction);
1382
1383         btrfs_scrub_pause(root);
1384         /* btrfs_commit_tree_roots is responsible for getting the
1385          * various roots consistent with each other.  Every pointer
1386          * in the tree of tree roots has to point to the most up to date
1387          * root for every subvolume and other tree.  So, we have to keep
1388          * the tree logging code from jumping in and changing any
1389          * of the trees.
1390          *
1391          * At this point in the commit, there can't be any tree-log
1392          * writers, but a little lower down we drop the trans mutex
1393          * and let new people in.  By holding the tree_log_mutex
1394          * from now until after the super is written, we avoid races
1395          * with the tree-log code.
1396          */
1397         mutex_lock(&root->fs_info->tree_log_mutex);
1398
1399         ret = commit_fs_roots(trans, root);
1400         if (ret) {
1401                 mutex_unlock(&root->fs_info->tree_log_mutex);
1402                 goto cleanup_transaction;
1403         }
1404
1405         /* commit_fs_roots gets rid of all the tree log roots, it is now
1406          * safe to free the root of tree log roots
1407          */
1408         btrfs_free_log_root_tree(trans, root->fs_info);
1409
1410         ret = commit_cowonly_roots(trans, root);
1411         if (ret) {
1412                 mutex_unlock(&root->fs_info->tree_log_mutex);
1413                 goto cleanup_transaction;
1414         }
1415
1416         btrfs_prepare_extent_commit(trans, root);
1417
1418         cur_trans = root->fs_info->running_transaction;
1419
1420         btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1421                             root->fs_info->tree_root->node);
1422         switch_commit_root(root->fs_info->tree_root);
1423
1424         btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1425                             root->fs_info->chunk_root->node);
1426         switch_commit_root(root->fs_info->chunk_root);
1427
1428         update_super_roots(root);
1429
1430         if (!root->fs_info->log_root_recovering) {
1431                 btrfs_set_super_log_root(root->fs_info->super_copy, 0);
1432                 btrfs_set_super_log_root_level(root->fs_info->super_copy, 0);
1433         }
1434
1435         memcpy(root->fs_info->super_for_commit, root->fs_info->super_copy,
1436                sizeof(*root->fs_info->super_copy));
1437
1438         trans->transaction->blocked = 0;
1439         spin_lock(&root->fs_info->trans_lock);
1440         root->fs_info->running_transaction = NULL;
1441         root->fs_info->trans_no_join = 0;
1442         spin_unlock(&root->fs_info->trans_lock);
1443         mutex_unlock(&root->fs_info->reloc_mutex);
1444
1445         wake_up(&root->fs_info->transaction_wait);
1446
1447         ret = btrfs_write_and_wait_transaction(trans, root);
1448         if (ret) {
1449                 btrfs_error(root->fs_info, ret,
1450                             "Error while writing out transaction.");
1451                 mutex_unlock(&root->fs_info->tree_log_mutex);
1452                 goto cleanup_transaction;
1453         }
1454
1455         ret = write_ctree_super(trans, root, 0);
1456         if (ret) {
1457                 mutex_unlock(&root->fs_info->tree_log_mutex);
1458                 goto cleanup_transaction;
1459         }
1460
1461         /*
1462          * the super is written, we can safely allow the tree-loggers
1463          * to go about their business
1464          */
1465         mutex_unlock(&root->fs_info->tree_log_mutex);
1466
1467         btrfs_finish_extent_commit(trans, root);
1468
1469         cur_trans->commit_done = 1;
1470
1471         root->fs_info->last_trans_committed = cur_trans->transid;
1472
1473         wake_up(&cur_trans->commit_wait);
1474
1475         spin_lock(&root->fs_info->trans_lock);
1476         list_del_init(&cur_trans->list);
1477         spin_unlock(&root->fs_info->trans_lock);
1478
1479         put_transaction(cur_trans);
1480         put_transaction(cur_trans);
1481
1482         trace_btrfs_transaction_commit(root);
1483
1484         btrfs_scrub_continue(root);
1485
1486         if (current->journal_info == trans)
1487                 current->journal_info = NULL;
1488
1489         kmem_cache_free(btrfs_trans_handle_cachep, trans);
1490
1491         if (current != root->fs_info->transaction_kthread)
1492                 btrfs_run_delayed_iputs(root);
1493
1494         return ret;
1495
1496 cleanup_transaction:
1497         btrfs_printk(root->fs_info, "Skipping commit of aborted transaction.\n");
1498 //      WARN_ON(1);
1499         if (current->journal_info == trans)
1500                 current->journal_info = NULL;
1501         cleanup_transaction(trans, root);
1502
1503         return ret;
1504 }
1505
1506 /*
1507  * interface function to delete all the snapshots we have scheduled for deletion
1508  */
1509 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1510 {
1511         LIST_HEAD(list);
1512         struct btrfs_fs_info *fs_info = root->fs_info;
1513
1514         spin_lock(&fs_info->trans_lock);
1515         list_splice_init(&fs_info->dead_roots, &list);
1516         spin_unlock(&fs_info->trans_lock);
1517
1518         while (!list_empty(&list)) {
1519                 int ret;
1520
1521                 root = list_entry(list.next, struct btrfs_root, root_list);
1522                 list_del(&root->root_list);
1523
1524                 btrfs_kill_all_delayed_nodes(root);
1525
1526                 if (btrfs_header_backref_rev(root->node) <
1527                     BTRFS_MIXED_BACKREF_REV)
1528                         ret = btrfs_drop_snapshot(root, NULL, 0, 0);
1529                 else
1530                         ret =btrfs_drop_snapshot(root, NULL, 1, 0);
1531                 BUG_ON(ret < 0);
1532         }
1533         return 0;
1534 }