btusb bluetooth driver: wait for 'waker' work too before closing
[linux-2.6.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/sched.h>
21 #include <linux/writeback.h>
22 #include <linux/pagemap.h>
23 #include <linux/blkdev.h>
24 #include "ctree.h"
25 #include "disk-io.h"
26 #include "transaction.h"
27 #include "locking.h"
28 #include "tree-log.h"
29
30 #define BTRFS_ROOT_TRANS_TAG 0
31
32 static noinline void put_transaction(struct btrfs_transaction *transaction)
33 {
34         WARN_ON(transaction->use_count == 0);
35         transaction->use_count--;
36         if (transaction->use_count == 0) {
37                 list_del_init(&transaction->list);
38                 memset(transaction, 0, sizeof(*transaction));
39                 kmem_cache_free(btrfs_transaction_cachep, transaction);
40         }
41 }
42
43 static noinline void switch_commit_root(struct btrfs_root *root)
44 {
45         free_extent_buffer(root->commit_root);
46         root->commit_root = btrfs_root_node(root);
47 }
48
49 /*
50  * either allocate a new transaction or hop into the existing one
51  */
52 static noinline int join_transaction(struct btrfs_root *root)
53 {
54         struct btrfs_transaction *cur_trans;
55         cur_trans = root->fs_info->running_transaction;
56         if (!cur_trans) {
57                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
58                                              GFP_NOFS);
59                 BUG_ON(!cur_trans);
60                 root->fs_info->generation++;
61                 cur_trans->num_writers = 1;
62                 cur_trans->num_joined = 0;
63                 cur_trans->transid = root->fs_info->generation;
64                 init_waitqueue_head(&cur_trans->writer_wait);
65                 init_waitqueue_head(&cur_trans->commit_wait);
66                 cur_trans->in_commit = 0;
67                 cur_trans->blocked = 0;
68                 cur_trans->use_count = 1;
69                 cur_trans->commit_done = 0;
70                 cur_trans->start_time = get_seconds();
71
72                 cur_trans->delayed_refs.root.rb_node = NULL;
73                 cur_trans->delayed_refs.num_entries = 0;
74                 cur_trans->delayed_refs.num_heads_ready = 0;
75                 cur_trans->delayed_refs.num_heads = 0;
76                 cur_trans->delayed_refs.flushing = 0;
77                 cur_trans->delayed_refs.run_delayed_start = 0;
78                 spin_lock_init(&cur_trans->delayed_refs.lock);
79
80                 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
81                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
82                 extent_io_tree_init(&cur_trans->dirty_pages,
83                                      root->fs_info->btree_inode->i_mapping,
84                                      GFP_NOFS);
85                 spin_lock(&root->fs_info->new_trans_lock);
86                 root->fs_info->running_transaction = cur_trans;
87                 spin_unlock(&root->fs_info->new_trans_lock);
88         } else {
89                 cur_trans->num_writers++;
90                 cur_trans->num_joined++;
91         }
92
93         return 0;
94 }
95
96 /*
97  * this does all the record keeping required to make sure that a reference
98  * counted root is properly recorded in a given transaction.  This is required
99  * to make sure the old root from before we joined the transaction is deleted
100  * when the transaction commits
101  */
102 static noinline int record_root_in_trans(struct btrfs_trans_handle *trans,
103                                          struct btrfs_root *root)
104 {
105         if (root->ref_cows && root->last_trans < trans->transid) {
106                 WARN_ON(root == root->fs_info->extent_root);
107                 WARN_ON(root->commit_root != root->node);
108
109                 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
110                            (unsigned long)root->root_key.objectid,
111                            BTRFS_ROOT_TRANS_TAG);
112                 root->last_trans = trans->transid;
113                 btrfs_init_reloc_root(trans, root);
114         }
115         return 0;
116 }
117
118 int btrfs_record_root_in_trans(struct btrfs_trans_handle *trans,
119                                struct btrfs_root *root)
120 {
121         if (!root->ref_cows)
122                 return 0;
123
124         mutex_lock(&root->fs_info->trans_mutex);
125         if (root->last_trans == trans->transid) {
126                 mutex_unlock(&root->fs_info->trans_mutex);
127                 return 0;
128         }
129
130         record_root_in_trans(trans, root);
131         mutex_unlock(&root->fs_info->trans_mutex);
132         return 0;
133 }
134
135 /* wait for commit against the current transaction to become unblocked
136  * when this is done, it is safe to start a new transaction, but the current
137  * transaction might not be fully on disk.
138  */
139 static void wait_current_trans(struct btrfs_root *root)
140 {
141         struct btrfs_transaction *cur_trans;
142
143         cur_trans = root->fs_info->running_transaction;
144         if (cur_trans && cur_trans->blocked) {
145                 DEFINE_WAIT(wait);
146                 cur_trans->use_count++;
147                 while (1) {
148                         prepare_to_wait(&root->fs_info->transaction_wait, &wait,
149                                         TASK_UNINTERRUPTIBLE);
150                         if (cur_trans->blocked) {
151                                 mutex_unlock(&root->fs_info->trans_mutex);
152                                 schedule();
153                                 mutex_lock(&root->fs_info->trans_mutex);
154                                 finish_wait(&root->fs_info->transaction_wait,
155                                             &wait);
156                         } else {
157                                 finish_wait(&root->fs_info->transaction_wait,
158                                             &wait);
159                                 break;
160                         }
161                 }
162                 put_transaction(cur_trans);
163         }
164 }
165
166 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
167                                              int num_blocks, int wait)
168 {
169         struct btrfs_trans_handle *h =
170                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
171         int ret;
172
173         mutex_lock(&root->fs_info->trans_mutex);
174         if (!root->fs_info->log_root_recovering &&
175             ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
176                 wait_current_trans(root);
177         ret = join_transaction(root);
178         BUG_ON(ret);
179
180         h->transid = root->fs_info->running_transaction->transid;
181         h->transaction = root->fs_info->running_transaction;
182         h->blocks_reserved = num_blocks;
183         h->blocks_used = 0;
184         h->block_group = 0;
185         h->alloc_exclude_nr = 0;
186         h->alloc_exclude_start = 0;
187         h->delayed_ref_updates = 0;
188
189         if (!current->journal_info)
190                 current->journal_info = h;
191
192         root->fs_info->running_transaction->use_count++;
193         record_root_in_trans(h, root);
194         mutex_unlock(&root->fs_info->trans_mutex);
195         return h;
196 }
197
198 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
199                                                    int num_blocks)
200 {
201         return start_transaction(root, num_blocks, 1);
202 }
203 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
204                                                    int num_blocks)
205 {
206         return start_transaction(root, num_blocks, 0);
207 }
208
209 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
210                                                          int num_blocks)
211 {
212         return start_transaction(r, num_blocks, 2);
213 }
214
215 /* wait for a transaction commit to be fully complete */
216 static noinline int wait_for_commit(struct btrfs_root *root,
217                                     struct btrfs_transaction *commit)
218 {
219         DEFINE_WAIT(wait);
220         mutex_lock(&root->fs_info->trans_mutex);
221         while (!commit->commit_done) {
222                 prepare_to_wait(&commit->commit_wait, &wait,
223                                 TASK_UNINTERRUPTIBLE);
224                 if (commit->commit_done)
225                         break;
226                 mutex_unlock(&root->fs_info->trans_mutex);
227                 schedule();
228                 mutex_lock(&root->fs_info->trans_mutex);
229         }
230         mutex_unlock(&root->fs_info->trans_mutex);
231         finish_wait(&commit->commit_wait, &wait);
232         return 0;
233 }
234
235 #if 0
236 /*
237  * rate limit against the drop_snapshot code.  This helps to slow down new
238  * operations if the drop_snapshot code isn't able to keep up.
239  */
240 static void throttle_on_drops(struct btrfs_root *root)
241 {
242         struct btrfs_fs_info *info = root->fs_info;
243         int harder_count = 0;
244
245 harder:
246         if (atomic_read(&info->throttles)) {
247                 DEFINE_WAIT(wait);
248                 int thr;
249                 thr = atomic_read(&info->throttle_gen);
250
251                 do {
252                         prepare_to_wait(&info->transaction_throttle,
253                                         &wait, TASK_UNINTERRUPTIBLE);
254                         if (!atomic_read(&info->throttles)) {
255                                 finish_wait(&info->transaction_throttle, &wait);
256                                 break;
257                         }
258                         schedule();
259                         finish_wait(&info->transaction_throttle, &wait);
260                 } while (thr == atomic_read(&info->throttle_gen));
261                 harder_count++;
262
263                 if (root->fs_info->total_ref_cache_size > 1 * 1024 * 1024 &&
264                     harder_count < 2)
265                         goto harder;
266
267                 if (root->fs_info->total_ref_cache_size > 5 * 1024 * 1024 &&
268                     harder_count < 10)
269                         goto harder;
270
271                 if (root->fs_info->total_ref_cache_size > 10 * 1024 * 1024 &&
272                     harder_count < 20)
273                         goto harder;
274         }
275 }
276 #endif
277
278 void btrfs_throttle(struct btrfs_root *root)
279 {
280         mutex_lock(&root->fs_info->trans_mutex);
281         if (!root->fs_info->open_ioctl_trans)
282                 wait_current_trans(root);
283         mutex_unlock(&root->fs_info->trans_mutex);
284 }
285
286 static int __btrfs_end_transaction(struct btrfs_trans_handle *trans,
287                           struct btrfs_root *root, int throttle)
288 {
289         struct btrfs_transaction *cur_trans;
290         struct btrfs_fs_info *info = root->fs_info;
291         int count = 0;
292
293         while (count < 4) {
294                 unsigned long cur = trans->delayed_ref_updates;
295                 trans->delayed_ref_updates = 0;
296                 if (cur &&
297                     trans->transaction->delayed_refs.num_heads_ready > 64) {
298                         trans->delayed_ref_updates = 0;
299
300                         /*
301                          * do a full flush if the transaction is trying
302                          * to close
303                          */
304                         if (trans->transaction->delayed_refs.flushing)
305                                 cur = 0;
306                         btrfs_run_delayed_refs(trans, root, cur);
307                 } else {
308                         break;
309                 }
310                 count++;
311         }
312
313         mutex_lock(&info->trans_mutex);
314         cur_trans = info->running_transaction;
315         WARN_ON(cur_trans != trans->transaction);
316         WARN_ON(cur_trans->num_writers < 1);
317         cur_trans->num_writers--;
318
319         if (waitqueue_active(&cur_trans->writer_wait))
320                 wake_up(&cur_trans->writer_wait);
321         put_transaction(cur_trans);
322         mutex_unlock(&info->trans_mutex);
323
324         if (current->journal_info == trans)
325                 current->journal_info = NULL;
326         memset(trans, 0, sizeof(*trans));
327         kmem_cache_free(btrfs_trans_handle_cachep, trans);
328
329         return 0;
330 }
331
332 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
333                           struct btrfs_root *root)
334 {
335         return __btrfs_end_transaction(trans, root, 0);
336 }
337
338 int btrfs_end_transaction_throttle(struct btrfs_trans_handle *trans,
339                                    struct btrfs_root *root)
340 {
341         return __btrfs_end_transaction(trans, root, 1);
342 }
343
344 /*
345  * when btree blocks are allocated, they have some corresponding bits set for
346  * them in one of two extent_io trees.  This is used to make sure all of
347  * those extents are sent to disk but does not wait on them
348  */
349 int btrfs_write_marked_extents(struct btrfs_root *root,
350                                struct extent_io_tree *dirty_pages)
351 {
352         int ret;
353         int err = 0;
354         int werr = 0;
355         struct page *page;
356         struct inode *btree_inode = root->fs_info->btree_inode;
357         u64 start = 0;
358         u64 end;
359         unsigned long index;
360
361         while (1) {
362                 ret = find_first_extent_bit(dirty_pages, start, &start, &end,
363                                             EXTENT_DIRTY);
364                 if (ret)
365                         break;
366                 while (start <= end) {
367                         cond_resched();
368
369                         index = start >> PAGE_CACHE_SHIFT;
370                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
371                         page = find_get_page(btree_inode->i_mapping, index);
372                         if (!page)
373                                 continue;
374
375                         btree_lock_page_hook(page);
376                         if (!page->mapping) {
377                                 unlock_page(page);
378                                 page_cache_release(page);
379                                 continue;
380                         }
381
382                         if (PageWriteback(page)) {
383                                 if (PageDirty(page))
384                                         wait_on_page_writeback(page);
385                                 else {
386                                         unlock_page(page);
387                                         page_cache_release(page);
388                                         continue;
389                                 }
390                         }
391                         err = write_one_page(page, 0);
392                         if (err)
393                                 werr = err;
394                         page_cache_release(page);
395                 }
396         }
397         if (err)
398                 werr = err;
399         return werr;
400 }
401
402 /*
403  * when btree blocks are allocated, they have some corresponding bits set for
404  * them in one of two extent_io trees.  This is used to make sure all of
405  * those extents are on disk for transaction or log commit.  We wait
406  * on all the pages and clear them from the dirty pages state tree
407  */
408 int btrfs_wait_marked_extents(struct btrfs_root *root,
409                               struct extent_io_tree *dirty_pages)
410 {
411         int ret;
412         int err = 0;
413         int werr = 0;
414         struct page *page;
415         struct inode *btree_inode = root->fs_info->btree_inode;
416         u64 start = 0;
417         u64 end;
418         unsigned long index;
419
420         while (1) {
421                 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
422                                             EXTENT_DIRTY);
423                 if (ret)
424                         break;
425
426                 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
427                 while (start <= end) {
428                         index = start >> PAGE_CACHE_SHIFT;
429                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
430                         page = find_get_page(btree_inode->i_mapping, index);
431                         if (!page)
432                                 continue;
433                         if (PageDirty(page)) {
434                                 btree_lock_page_hook(page);
435                                 wait_on_page_writeback(page);
436                                 err = write_one_page(page, 0);
437                                 if (err)
438                                         werr = err;
439                         }
440                         wait_on_page_writeback(page);
441                         page_cache_release(page);
442                         cond_resched();
443                 }
444         }
445         if (err)
446                 werr = err;
447         return werr;
448 }
449
450 /*
451  * when btree blocks are allocated, they have some corresponding bits set for
452  * them in one of two extent_io trees.  This is used to make sure all of
453  * those extents are on disk for transaction or log commit
454  */
455 int btrfs_write_and_wait_marked_extents(struct btrfs_root *root,
456                                         struct extent_io_tree *dirty_pages)
457 {
458         int ret;
459         int ret2;
460
461         ret = btrfs_write_marked_extents(root, dirty_pages);
462         ret2 = btrfs_wait_marked_extents(root, dirty_pages);
463         return ret || ret2;
464 }
465
466 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
467                                      struct btrfs_root *root)
468 {
469         if (!trans || !trans->transaction) {
470                 struct inode *btree_inode;
471                 btree_inode = root->fs_info->btree_inode;
472                 return filemap_write_and_wait(btree_inode->i_mapping);
473         }
474         return btrfs_write_and_wait_marked_extents(root,
475                                            &trans->transaction->dirty_pages);
476 }
477
478 /*
479  * this is used to update the root pointer in the tree of tree roots.
480  *
481  * But, in the case of the extent allocation tree, updating the root
482  * pointer may allocate blocks which may change the root of the extent
483  * allocation tree.
484  *
485  * So, this loops and repeats and makes sure the cowonly root didn't
486  * change while the root pointer was being updated in the metadata.
487  */
488 static int update_cowonly_root(struct btrfs_trans_handle *trans,
489                                struct btrfs_root *root)
490 {
491         int ret;
492         u64 old_root_bytenr;
493         struct btrfs_root *tree_root = root->fs_info->tree_root;
494
495         btrfs_write_dirty_block_groups(trans, root);
496
497         while (1) {
498                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
499                 if (old_root_bytenr == root->node->start)
500                         break;
501
502                 btrfs_set_root_node(&root->root_item, root->node);
503                 ret = btrfs_update_root(trans, tree_root,
504                                         &root->root_key,
505                                         &root->root_item);
506                 BUG_ON(ret);
507
508                 ret = btrfs_write_dirty_block_groups(trans, root);
509                 BUG_ON(ret);
510         }
511
512         if (root != root->fs_info->extent_root)
513                 switch_commit_root(root);
514
515         return 0;
516 }
517
518 /*
519  * update all the cowonly tree roots on disk
520  */
521 static noinline int commit_cowonly_roots(struct btrfs_trans_handle *trans,
522                                          struct btrfs_root *root)
523 {
524         struct btrfs_fs_info *fs_info = root->fs_info;
525         struct list_head *next;
526         struct extent_buffer *eb;
527         int ret;
528
529         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
530         BUG_ON(ret);
531
532         eb = btrfs_lock_root_node(fs_info->tree_root);
533         btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
534         btrfs_tree_unlock(eb);
535         free_extent_buffer(eb);
536
537         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
538         BUG_ON(ret);
539
540         while (!list_empty(&fs_info->dirty_cowonly_roots)) {
541                 next = fs_info->dirty_cowonly_roots.next;
542                 list_del_init(next);
543                 root = list_entry(next, struct btrfs_root, dirty_list);
544
545                 update_cowonly_root(trans, root);
546         }
547
548         down_write(&fs_info->extent_commit_sem);
549         switch_commit_root(fs_info->extent_root);
550         up_write(&fs_info->extent_commit_sem);
551
552         return 0;
553 }
554
555 /*
556  * dead roots are old snapshots that need to be deleted.  This allocates
557  * a dirty root struct and adds it into the list of dead roots that need to
558  * be deleted
559  */
560 int btrfs_add_dead_root(struct btrfs_root *root)
561 {
562         mutex_lock(&root->fs_info->trans_mutex);
563         list_add(&root->root_list, &root->fs_info->dead_roots);
564         mutex_unlock(&root->fs_info->trans_mutex);
565         return 0;
566 }
567
568 /*
569  * update all the cowonly tree roots on disk
570  */
571 static noinline int commit_fs_roots(struct btrfs_trans_handle *trans,
572                                     struct btrfs_root *root)
573 {
574         struct btrfs_root *gang[8];
575         struct btrfs_fs_info *fs_info = root->fs_info;
576         int i;
577         int ret;
578         int err = 0;
579
580         while (1) {
581                 ret = radix_tree_gang_lookup_tag(&fs_info->fs_roots_radix,
582                                                  (void **)gang, 0,
583                                                  ARRAY_SIZE(gang),
584                                                  BTRFS_ROOT_TRANS_TAG);
585                 if (ret == 0)
586                         break;
587                 for (i = 0; i < ret; i++) {
588                         root = gang[i];
589                         radix_tree_tag_clear(&fs_info->fs_roots_radix,
590                                         (unsigned long)root->root_key.objectid,
591                                         BTRFS_ROOT_TRANS_TAG);
592
593                         btrfs_free_log(trans, root);
594                         btrfs_update_reloc_root(trans, root);
595
596                         if (root->commit_root != root->node) {
597                                 switch_commit_root(root);
598                                 btrfs_set_root_node(&root->root_item,
599                                                     root->node);
600                         }
601
602                         err = btrfs_update_root(trans, fs_info->tree_root,
603                                                 &root->root_key,
604                                                 &root->root_item);
605                         if (err)
606                                 break;
607                 }
608         }
609         return err;
610 }
611
612 /*
613  * defrag a given btree.  If cacheonly == 1, this won't read from the disk,
614  * otherwise every leaf in the btree is read and defragged.
615  */
616 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
617 {
618         struct btrfs_fs_info *info = root->fs_info;
619         int ret;
620         struct btrfs_trans_handle *trans;
621         unsigned long nr;
622
623         smp_mb();
624         if (root->defrag_running)
625                 return 0;
626         trans = btrfs_start_transaction(root, 1);
627         while (1) {
628                 root->defrag_running = 1;
629                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
630                 nr = trans->blocks_used;
631                 btrfs_end_transaction(trans, root);
632                 btrfs_btree_balance_dirty(info->tree_root, nr);
633                 cond_resched();
634
635                 trans = btrfs_start_transaction(root, 1);
636                 if (root->fs_info->closing || ret != -EAGAIN)
637                         break;
638         }
639         root->defrag_running = 0;
640         smp_mb();
641         btrfs_end_transaction(trans, root);
642         return 0;
643 }
644
645 #if 0
646 /*
647  * when dropping snapshots, we generate a ton of delayed refs, and it makes
648  * sense not to join the transaction while it is trying to flush the current
649  * queue of delayed refs out.
650  *
651  * This is used by the drop snapshot code only
652  */
653 static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
654 {
655         DEFINE_WAIT(wait);
656
657         mutex_lock(&info->trans_mutex);
658         while (info->running_transaction &&
659                info->running_transaction->delayed_refs.flushing) {
660                 prepare_to_wait(&info->transaction_wait, &wait,
661                                 TASK_UNINTERRUPTIBLE);
662                 mutex_unlock(&info->trans_mutex);
663
664                 schedule();
665
666                 mutex_lock(&info->trans_mutex);
667                 finish_wait(&info->transaction_wait, &wait);
668         }
669         mutex_unlock(&info->trans_mutex);
670         return 0;
671 }
672
673 /*
674  * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
675  * all of them
676  */
677 int btrfs_drop_dead_root(struct btrfs_root *root)
678 {
679         struct btrfs_trans_handle *trans;
680         struct btrfs_root *tree_root = root->fs_info->tree_root;
681         unsigned long nr;
682         int ret;
683
684         while (1) {
685                 /*
686                  * we don't want to jump in and create a bunch of
687                  * delayed refs if the transaction is starting to close
688                  */
689                 wait_transaction_pre_flush(tree_root->fs_info);
690                 trans = btrfs_start_transaction(tree_root, 1);
691
692                 /*
693                  * we've joined a transaction, make sure it isn't
694                  * closing right now
695                  */
696                 if (trans->transaction->delayed_refs.flushing) {
697                         btrfs_end_transaction(trans, tree_root);
698                         continue;
699                 }
700
701                 ret = btrfs_drop_snapshot(trans, root);
702                 if (ret != -EAGAIN)
703                         break;
704
705                 ret = btrfs_update_root(trans, tree_root,
706                                         &root->root_key,
707                                         &root->root_item);
708                 if (ret)
709                         break;
710
711                 nr = trans->blocks_used;
712                 ret = btrfs_end_transaction(trans, tree_root);
713                 BUG_ON(ret);
714
715                 btrfs_btree_balance_dirty(tree_root, nr);
716                 cond_resched();
717         }
718         BUG_ON(ret);
719
720         ret = btrfs_del_root(trans, tree_root, &root->root_key);
721         BUG_ON(ret);
722
723         nr = trans->blocks_used;
724         ret = btrfs_end_transaction(trans, tree_root);
725         BUG_ON(ret);
726
727         free_extent_buffer(root->node);
728         free_extent_buffer(root->commit_root);
729         kfree(root);
730
731         btrfs_btree_balance_dirty(tree_root, nr);
732         return ret;
733 }
734 #endif
735
736 /*
737  * new snapshots need to be created at a very specific time in the
738  * transaction commit.  This does the actual creation
739  */
740 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
741                                    struct btrfs_fs_info *fs_info,
742                                    struct btrfs_pending_snapshot *pending)
743 {
744         struct btrfs_key key;
745         struct btrfs_root_item *new_root_item;
746         struct btrfs_root *tree_root = fs_info->tree_root;
747         struct btrfs_root *root = pending->root;
748         struct extent_buffer *tmp;
749         struct extent_buffer *old;
750         int ret;
751         u64 objectid;
752
753         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
754         if (!new_root_item) {
755                 ret = -ENOMEM;
756                 goto fail;
757         }
758         ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
759         if (ret)
760                 goto fail;
761
762         record_root_in_trans(trans, root);
763         btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
764         memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
765
766         key.objectid = objectid;
767         /* record when the snapshot was created in key.offset */
768         key.offset = trans->transid;
769         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
770
771         old = btrfs_lock_root_node(root);
772         btrfs_cow_block(trans, root, old, NULL, 0, &old);
773         btrfs_set_lock_blocking(old);
774
775         btrfs_copy_root(trans, root, old, &tmp, objectid);
776         btrfs_tree_unlock(old);
777         free_extent_buffer(old);
778
779         btrfs_set_root_node(new_root_item, tmp);
780         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
781                                 new_root_item);
782         btrfs_tree_unlock(tmp);
783         free_extent_buffer(tmp);
784         if (ret)
785                 goto fail;
786
787         key.offset = (u64)-1;
788         memcpy(&pending->root_key, &key, sizeof(key));
789 fail:
790         kfree(new_root_item);
791         btrfs_unreserve_metadata_space(root, 6);
792         return ret;
793 }
794
795 static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
796                                    struct btrfs_pending_snapshot *pending)
797 {
798         int ret;
799         int namelen;
800         u64 index = 0;
801         struct btrfs_trans_handle *trans;
802         struct inode *parent_inode;
803         struct inode *inode;
804         struct btrfs_root *parent_root;
805
806         parent_inode = pending->dentry->d_parent->d_inode;
807         parent_root = BTRFS_I(parent_inode)->root;
808         trans = btrfs_join_transaction(parent_root, 1);
809
810         /*
811          * insert the directory item
812          */
813         namelen = strlen(pending->name);
814         ret = btrfs_set_inode_index(parent_inode, &index);
815         ret = btrfs_insert_dir_item(trans, parent_root,
816                             pending->name, namelen,
817                             parent_inode->i_ino,
818                             &pending->root_key, BTRFS_FT_DIR, index);
819
820         if (ret)
821                 goto fail;
822
823         btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
824         ret = btrfs_update_inode(trans, parent_root, parent_inode);
825         BUG_ON(ret);
826
827         ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
828                                  pending->root_key.objectid,
829                                  parent_root->root_key.objectid,
830                                  parent_inode->i_ino, index, pending->name,
831                                  namelen);
832
833         BUG_ON(ret);
834
835         inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
836         d_instantiate(pending->dentry, inode);
837 fail:
838         btrfs_end_transaction(trans, fs_info->fs_root);
839         return ret;
840 }
841
842 /*
843  * create all the snapshots we've scheduled for creation
844  */
845 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
846                                              struct btrfs_fs_info *fs_info)
847 {
848         struct btrfs_pending_snapshot *pending;
849         struct list_head *head = &trans->transaction->pending_snapshots;
850         int ret;
851
852         list_for_each_entry(pending, head, list) {
853                 ret = create_pending_snapshot(trans, fs_info, pending);
854                 BUG_ON(ret);
855         }
856         return 0;
857 }
858
859 static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
860                                              struct btrfs_fs_info *fs_info)
861 {
862         struct btrfs_pending_snapshot *pending;
863         struct list_head *head = &trans->transaction->pending_snapshots;
864         int ret;
865
866         while (!list_empty(head)) {
867                 pending = list_entry(head->next,
868                                      struct btrfs_pending_snapshot, list);
869                 ret = finish_pending_snapshot(fs_info, pending);
870                 BUG_ON(ret);
871                 list_del(&pending->list);
872                 kfree(pending->name);
873                 kfree(pending);
874         }
875         return 0;
876 }
877
878 static void update_super_roots(struct btrfs_root *root)
879 {
880         struct btrfs_root_item *root_item;
881         struct btrfs_super_block *super;
882
883         super = &root->fs_info->super_copy;
884
885         root_item = &root->fs_info->chunk_root->root_item;
886         super->chunk_root = root_item->bytenr;
887         super->chunk_root_generation = root_item->generation;
888         super->chunk_root_level = root_item->level;
889
890         root_item = &root->fs_info->tree_root->root_item;
891         super->root = root_item->bytenr;
892         super->generation = root_item->generation;
893         super->root_level = root_item->level;
894 }
895
896 int btrfs_transaction_in_commit(struct btrfs_fs_info *info)
897 {
898         int ret = 0;
899         spin_lock(&info->new_trans_lock);
900         if (info->running_transaction)
901                 ret = info->running_transaction->in_commit;
902         spin_unlock(&info->new_trans_lock);
903         return ret;
904 }
905
906 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
907                              struct btrfs_root *root)
908 {
909         unsigned long joined = 0;
910         unsigned long timeout = 1;
911         struct btrfs_transaction *cur_trans;
912         struct btrfs_transaction *prev_trans = NULL;
913         DEFINE_WAIT(wait);
914         int ret;
915         int should_grow = 0;
916         unsigned long now = get_seconds();
917         int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
918
919         btrfs_run_ordered_operations(root, 0);
920
921         /* make a pass through all the delayed refs we have so far
922          * any runnings procs may add more while we are here
923          */
924         ret = btrfs_run_delayed_refs(trans, root, 0);
925         BUG_ON(ret);
926
927         cur_trans = trans->transaction;
928         /*
929          * set the flushing flag so procs in this transaction have to
930          * start sending their work down.
931          */
932         cur_trans->delayed_refs.flushing = 1;
933
934         ret = btrfs_run_delayed_refs(trans, root, 0);
935         BUG_ON(ret);
936
937         mutex_lock(&root->fs_info->trans_mutex);
938         if (cur_trans->in_commit) {
939                 cur_trans->use_count++;
940                 mutex_unlock(&root->fs_info->trans_mutex);
941                 btrfs_end_transaction(trans, root);
942
943                 ret = wait_for_commit(root, cur_trans);
944                 BUG_ON(ret);
945
946                 mutex_lock(&root->fs_info->trans_mutex);
947                 put_transaction(cur_trans);
948                 mutex_unlock(&root->fs_info->trans_mutex);
949
950                 return 0;
951         }
952
953         trans->transaction->in_commit = 1;
954         trans->transaction->blocked = 1;
955         if (cur_trans->list.prev != &root->fs_info->trans_list) {
956                 prev_trans = list_entry(cur_trans->list.prev,
957                                         struct btrfs_transaction, list);
958                 if (!prev_trans->commit_done) {
959                         prev_trans->use_count++;
960                         mutex_unlock(&root->fs_info->trans_mutex);
961
962                         wait_for_commit(root, prev_trans);
963
964                         mutex_lock(&root->fs_info->trans_mutex);
965                         put_transaction(prev_trans);
966                 }
967         }
968
969         if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
970                 should_grow = 1;
971
972         do {
973                 int snap_pending = 0;
974                 joined = cur_trans->num_joined;
975                 if (!list_empty(&trans->transaction->pending_snapshots))
976                         snap_pending = 1;
977
978                 WARN_ON(cur_trans != trans->transaction);
979                 prepare_to_wait(&cur_trans->writer_wait, &wait,
980                                 TASK_UNINTERRUPTIBLE);
981
982                 if (cur_trans->num_writers > 1)
983                         timeout = MAX_SCHEDULE_TIMEOUT;
984                 else if (should_grow)
985                         timeout = 1;
986
987                 mutex_unlock(&root->fs_info->trans_mutex);
988
989                 if (flush_on_commit) {
990                         btrfs_start_delalloc_inodes(root);
991                         ret = btrfs_wait_ordered_extents(root, 0);
992                         BUG_ON(ret);
993                 } else if (snap_pending) {
994                         ret = btrfs_wait_ordered_extents(root, 1);
995                         BUG_ON(ret);
996                 }
997
998                 /*
999                  * rename don't use btrfs_join_transaction, so, once we
1000                  * set the transaction to blocked above, we aren't going
1001                  * to get any new ordered operations.  We can safely run
1002                  * it here and no for sure that nothing new will be added
1003                  * to the list
1004                  */
1005                 btrfs_run_ordered_operations(root, 1);
1006
1007                 smp_mb();
1008                 if (cur_trans->num_writers > 1 || should_grow)
1009                         schedule_timeout(timeout);
1010
1011                 mutex_lock(&root->fs_info->trans_mutex);
1012                 finish_wait(&cur_trans->writer_wait, &wait);
1013         } while (cur_trans->num_writers > 1 ||
1014                  (should_grow && cur_trans->num_joined != joined));
1015
1016         ret = create_pending_snapshots(trans, root->fs_info);
1017         BUG_ON(ret);
1018
1019         ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1020         BUG_ON(ret);
1021
1022         WARN_ON(cur_trans != trans->transaction);
1023
1024         /* btrfs_commit_tree_roots is responsible for getting the
1025          * various roots consistent with each other.  Every pointer
1026          * in the tree of tree roots has to point to the most up to date
1027          * root for every subvolume and other tree.  So, we have to keep
1028          * the tree logging code from jumping in and changing any
1029          * of the trees.
1030          *
1031          * At this point in the commit, there can't be any tree-log
1032          * writers, but a little lower down we drop the trans mutex
1033          * and let new people in.  By holding the tree_log_mutex
1034          * from now until after the super is written, we avoid races
1035          * with the tree-log code.
1036          */
1037         mutex_lock(&root->fs_info->tree_log_mutex);
1038
1039         ret = commit_fs_roots(trans, root);
1040         BUG_ON(ret);
1041
1042         /* commit_fs_roots gets rid of all the tree log roots, it is now
1043          * safe to free the root of tree log roots
1044          */
1045         btrfs_free_log_root_tree(trans, root->fs_info);
1046
1047         ret = commit_cowonly_roots(trans, root);
1048         BUG_ON(ret);
1049
1050         btrfs_prepare_extent_commit(trans, root);
1051
1052         cur_trans = root->fs_info->running_transaction;
1053         spin_lock(&root->fs_info->new_trans_lock);
1054         root->fs_info->running_transaction = NULL;
1055         spin_unlock(&root->fs_info->new_trans_lock);
1056
1057         btrfs_set_root_node(&root->fs_info->tree_root->root_item,
1058                             root->fs_info->tree_root->node);
1059         switch_commit_root(root->fs_info->tree_root);
1060
1061         btrfs_set_root_node(&root->fs_info->chunk_root->root_item,
1062                             root->fs_info->chunk_root->node);
1063         switch_commit_root(root->fs_info->chunk_root);
1064
1065         update_super_roots(root);
1066
1067         if (!root->fs_info->log_root_recovering) {
1068                 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1069                 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1070         }
1071
1072         memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1073                sizeof(root->fs_info->super_copy));
1074
1075         trans->transaction->blocked = 0;
1076
1077         wake_up(&root->fs_info->transaction_wait);
1078
1079         mutex_unlock(&root->fs_info->trans_mutex);
1080         ret = btrfs_write_and_wait_transaction(trans, root);
1081         BUG_ON(ret);
1082         write_ctree_super(trans, root, 0);
1083
1084         /*
1085          * the super is written, we can safely allow the tree-loggers
1086          * to go about their business
1087          */
1088         mutex_unlock(&root->fs_info->tree_log_mutex);
1089
1090         btrfs_finish_extent_commit(trans, root);
1091
1092         /* do the directory inserts of any pending snapshot creations */
1093         finish_pending_snapshots(trans, root->fs_info);
1094
1095         mutex_lock(&root->fs_info->trans_mutex);
1096
1097         cur_trans->commit_done = 1;
1098
1099         root->fs_info->last_trans_committed = cur_trans->transid;
1100
1101         wake_up(&cur_trans->commit_wait);
1102
1103         put_transaction(cur_trans);
1104         put_transaction(cur_trans);
1105
1106         mutex_unlock(&root->fs_info->trans_mutex);
1107
1108         if (current->journal_info == trans)
1109                 current->journal_info = NULL;
1110
1111         kmem_cache_free(btrfs_trans_handle_cachep, trans);
1112         return ret;
1113 }
1114
1115 /*
1116  * interface function to delete all the snapshots we have scheduled for deletion
1117  */
1118 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1119 {
1120         LIST_HEAD(list);
1121         struct btrfs_fs_info *fs_info = root->fs_info;
1122
1123         mutex_lock(&fs_info->trans_mutex);
1124         list_splice_init(&fs_info->dead_roots, &list);
1125         mutex_unlock(&fs_info->trans_mutex);
1126
1127         while (!list_empty(&list)) {
1128                 root = list_entry(list.next, struct btrfs_root, root_list);
1129                 list_del(&root->root_list);
1130
1131                 if (btrfs_header_backref_rev(root->node) <
1132                     BTRFS_MIXED_BACKREF_REV)
1133                         btrfs_drop_snapshot(root, 0);
1134                 else
1135                         btrfs_drop_snapshot(root, 1);
1136         }
1137         return 0;
1138 }