c85cb48d95ee3dcd2aa1c8dbb1ad46971202563a
[linux-3.10.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 "ctree.h"
24 #include "disk-io.h"
25 #include "transaction.h"
26
27 static int total_trans = 0;
28 extern struct kmem_cache *btrfs_trans_handle_cachep;
29 extern struct kmem_cache *btrfs_transaction_cachep;
30
31 static struct workqueue_struct *trans_wq;
32
33 #define BTRFS_ROOT_TRANS_TAG 0
34 #define BTRFS_ROOT_DEFRAG_TAG 1
35
36 static noinline void put_transaction(struct btrfs_transaction *transaction)
37 {
38         WARN_ON(transaction->use_count == 0);
39         transaction->use_count--;
40         if (transaction->use_count == 0) {
41                 WARN_ON(total_trans == 0);
42                 total_trans--;
43                 list_del_init(&transaction->list);
44                 memset(transaction, 0, sizeof(*transaction));
45                 kmem_cache_free(btrfs_transaction_cachep, transaction);
46         }
47 }
48
49 static noinline int join_transaction(struct btrfs_root *root)
50 {
51         struct btrfs_transaction *cur_trans;
52         cur_trans = root->fs_info->running_transaction;
53         if (!cur_trans) {
54                 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
55                                              GFP_NOFS);
56                 total_trans++;
57                 BUG_ON(!cur_trans);
58                 root->fs_info->generation++;
59                 root->fs_info->running_transaction = cur_trans;
60                 root->fs_info->last_alloc = 0;
61                 root->fs_info->last_data_alloc = 0;
62                 cur_trans->num_writers = 1;
63                 cur_trans->num_joined = 0;
64                 cur_trans->transid = root->fs_info->generation;
65                 init_waitqueue_head(&cur_trans->writer_wait);
66                 init_waitqueue_head(&cur_trans->commit_wait);
67                 cur_trans->in_commit = 0;
68                 cur_trans->use_count = 1;
69                 cur_trans->commit_done = 0;
70                 cur_trans->start_time = get_seconds();
71                 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
72                 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
73                 btrfs_ordered_inode_tree_init(&cur_trans->ordered_inode_tree);
74                 extent_io_tree_init(&cur_trans->dirty_pages,
75                                      root->fs_info->btree_inode->i_mapping,
76                                      GFP_NOFS);
77         } else {
78                 cur_trans->num_writers++;
79                 cur_trans->num_joined++;
80         }
81
82         return 0;
83 }
84
85 static noinline int record_root_in_trans(struct btrfs_root *root)
86 {
87         u64 running_trans_id = root->fs_info->running_transaction->transid;
88         if (root->ref_cows && root->last_trans < running_trans_id) {
89                 WARN_ON(root == root->fs_info->extent_root);
90                 if (root->root_item.refs != 0) {
91                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
92                                    (unsigned long)root->root_key.objectid,
93                                    BTRFS_ROOT_TRANS_TAG);
94                         radix_tree_tag_set(&root->fs_info->fs_roots_radix,
95                                    (unsigned long)root->root_key.objectid,
96                                    BTRFS_ROOT_DEFRAG_TAG);
97                         root->commit_root = root->node;
98                         extent_buffer_get(root->node);
99                 } else {
100                         WARN_ON(1);
101                 }
102                 root->last_trans = running_trans_id;
103         }
104         return 0;
105 }
106
107 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
108                                                    int num_blocks)
109 {
110         struct btrfs_trans_handle *h =
111                 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
112         int ret;
113
114         mutex_lock(&root->fs_info->trans_mutex);
115         ret = join_transaction(root);
116         BUG_ON(ret);
117
118         record_root_in_trans(root);
119         h->transid = root->fs_info->running_transaction->transid;
120         h->transaction = root->fs_info->running_transaction;
121         h->blocks_reserved = num_blocks;
122         h->blocks_used = 0;
123         h->block_group = NULL;
124         h->alloc_exclude_nr = 0;
125         h->alloc_exclude_start = 0;
126         root->fs_info->running_transaction->use_count++;
127         mutex_unlock(&root->fs_info->trans_mutex);
128         return h;
129 }
130
131 int btrfs_end_transaction(struct btrfs_trans_handle *trans,
132                           struct btrfs_root *root)
133 {
134         struct btrfs_transaction *cur_trans;
135
136         mutex_lock(&root->fs_info->trans_mutex);
137         cur_trans = root->fs_info->running_transaction;
138         WARN_ON(cur_trans != trans->transaction);
139         WARN_ON(cur_trans->num_writers < 1);
140         cur_trans->num_writers--;
141         if (waitqueue_active(&cur_trans->writer_wait))
142                 wake_up(&cur_trans->writer_wait);
143         put_transaction(cur_trans);
144         mutex_unlock(&root->fs_info->trans_mutex);
145         memset(trans, 0, sizeof(*trans));
146         kmem_cache_free(btrfs_trans_handle_cachep, trans);
147         return 0;
148 }
149
150
151 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
152                                      struct btrfs_root *root)
153 {
154         int ret;
155         int err;
156         int werr = 0;
157         struct extent_io_tree *dirty_pages;
158         struct page *page;
159         struct inode *btree_inode = root->fs_info->btree_inode;
160         u64 start;
161         u64 end;
162         unsigned long index;
163
164         if (!trans || !trans->transaction) {
165                 return filemap_write_and_wait(btree_inode->i_mapping);
166         }
167         dirty_pages = &trans->transaction->dirty_pages;
168         while(1) {
169                 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
170                                             EXTENT_DIRTY);
171                 if (ret)
172                         break;
173                 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
174                 while(start <= end) {
175                         index = start >> PAGE_CACHE_SHIFT;
176                         start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
177                         page = find_lock_page(btree_inode->i_mapping, index);
178                         if (!page)
179                                 continue;
180                         if (PageWriteback(page)) {
181                                 if (PageDirty(page))
182                                         wait_on_page_writeback(page);
183                                 else {
184                                         unlock_page(page);
185                                         page_cache_release(page);
186                                         continue;
187                                 }
188                         }
189                         err = write_one_page(page, 0);
190                         if (err)
191                                 werr = err;
192                         page_cache_release(page);
193                 }
194         }
195         err = filemap_fdatawait(btree_inode->i_mapping);
196         if (err)
197                 werr = err;
198         return werr;
199 }
200
201 static int update_cowonly_root(struct btrfs_trans_handle *trans,
202                                struct btrfs_root *root)
203 {
204         int ret;
205         u64 old_root_bytenr;
206         struct btrfs_root *tree_root = root->fs_info->tree_root;
207
208         btrfs_write_dirty_block_groups(trans, root);
209         while(1) {
210                 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
211                 if (old_root_bytenr == root->node->start)
212                         break;
213                 btrfs_set_root_bytenr(&root->root_item,
214                                        root->node->start);
215                 btrfs_set_root_level(&root->root_item,
216                                      btrfs_header_level(root->node));
217                 ret = btrfs_update_root(trans, tree_root,
218                                         &root->root_key,
219                                         &root->root_item);
220                 BUG_ON(ret);
221                 btrfs_write_dirty_block_groups(trans, root);
222         }
223         return 0;
224 }
225
226 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
227                             struct btrfs_root *root)
228 {
229         struct btrfs_fs_info *fs_info = root->fs_info;
230         struct list_head *next;
231
232         while(!list_empty(&fs_info->dirty_cowonly_roots)) {
233                 next = fs_info->dirty_cowonly_roots.next;
234                 list_del_init(next);
235                 root = list_entry(next, struct btrfs_root, dirty_list);
236                 update_cowonly_root(trans, root);
237         }
238         return 0;
239 }
240
241 static noinline int wait_for_commit(struct btrfs_root *root,
242                                     struct btrfs_transaction *commit)
243 {
244         DEFINE_WAIT(wait);
245         mutex_lock(&root->fs_info->trans_mutex);
246         while(!commit->commit_done) {
247                 prepare_to_wait(&commit->commit_wait, &wait,
248                                 TASK_UNINTERRUPTIBLE);
249                 if (commit->commit_done)
250                         break;
251                 mutex_unlock(&root->fs_info->trans_mutex);
252                 schedule();
253                 mutex_lock(&root->fs_info->trans_mutex);
254         }
255         mutex_unlock(&root->fs_info->trans_mutex);
256         finish_wait(&commit->commit_wait, &wait);
257         return 0;
258 }
259
260 struct dirty_root {
261         struct list_head list;
262         struct btrfs_root *root;
263         struct btrfs_root *latest_root;
264 };
265
266 int btrfs_add_dead_root(struct btrfs_root *root,
267                         struct btrfs_root *latest,
268                         struct list_head *dead_list)
269 {
270         struct dirty_root *dirty;
271
272         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
273         if (!dirty)
274                 return -ENOMEM;
275         dirty->root = root;
276         dirty->latest_root = latest;
277         list_add(&dirty->list, dead_list);
278         return 0;
279 }
280
281 static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
282                                     struct radix_tree_root *radix,
283                                     struct list_head *list)
284 {
285         struct dirty_root *dirty;
286         struct btrfs_root *gang[8];
287         struct btrfs_root *root;
288         int i;
289         int ret;
290         int err = 0;
291         u32 refs;
292
293         while(1) {
294                 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
295                                                  ARRAY_SIZE(gang),
296                                                  BTRFS_ROOT_TRANS_TAG);
297                 if (ret == 0)
298                         break;
299                 for (i = 0; i < ret; i++) {
300                         root = gang[i];
301                         radix_tree_tag_clear(radix,
302                                      (unsigned long)root->root_key.objectid,
303                                      BTRFS_ROOT_TRANS_TAG);
304                         if (root->commit_root == root->node) {
305                                 WARN_ON(root->node->start !=
306                                         btrfs_root_bytenr(&root->root_item));
307                                 free_extent_buffer(root->commit_root);
308                                 root->commit_root = NULL;
309
310                                 /* make sure to update the root on disk
311                                  * so we get any updates to the block used
312                                  * counts
313                                  */
314                                 err = btrfs_update_root(trans,
315                                                 root->fs_info->tree_root,
316                                                 &root->root_key,
317                                                 &root->root_item);
318                                 continue;
319                         }
320                         dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
321                         BUG_ON(!dirty);
322                         dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
323                         BUG_ON(!dirty->root);
324
325                         memset(&root->root_item.drop_progress, 0,
326                                sizeof(struct btrfs_disk_key));
327                         root->root_item.drop_level = 0;
328
329                         memcpy(dirty->root, root, sizeof(*root));
330                         dirty->root->node = root->commit_root;
331                         dirty->latest_root = root;
332                         root->commit_root = NULL;
333
334                         root->root_key.offset = root->fs_info->generation;
335                         btrfs_set_root_bytenr(&root->root_item,
336                                               root->node->start);
337                         btrfs_set_root_level(&root->root_item,
338                                              btrfs_header_level(root->node));
339                         err = btrfs_insert_root(trans, root->fs_info->tree_root,
340                                                 &root->root_key,
341                                                 &root->root_item);
342                         if (err)
343                                 break;
344
345                         refs = btrfs_root_refs(&dirty->root->root_item);
346                         btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
347                         err = btrfs_update_root(trans, root->fs_info->tree_root,
348                                                 &dirty->root->root_key,
349                                                 &dirty->root->root_item);
350
351                         BUG_ON(err);
352                         if (refs == 1) {
353                                 list_add(&dirty->list, list);
354                         } else {
355                                 WARN_ON(1);
356                                 kfree(dirty->root);
357                                 kfree(dirty);
358                         }
359                 }
360         }
361         return err;
362 }
363
364 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
365 {
366         struct btrfs_fs_info *info = root->fs_info;
367         int ret;
368         struct btrfs_trans_handle *trans;
369         unsigned long nr;
370
371         if (root->defrag_running)
372                 return 0;
373         trans = btrfs_start_transaction(root, 1);
374         while (1) {
375                 root->defrag_running = 1;
376                 ret = btrfs_defrag_leaves(trans, root, cacheonly);
377                 nr = trans->blocks_used;
378                 btrfs_end_transaction(trans, root);
379                 mutex_unlock(&info->fs_mutex);
380                 btrfs_btree_balance_dirty(info->tree_root, nr);
381                 cond_resched();
382
383                 mutex_lock(&info->fs_mutex);
384                 trans = btrfs_start_transaction(root, 1);
385                 if (ret != -EAGAIN)
386                         break;
387         }
388         root->defrag_running = 0;
389         radix_tree_tag_clear(&info->fs_roots_radix,
390                      (unsigned long)root->root_key.objectid,
391                      BTRFS_ROOT_DEFRAG_TAG);
392         btrfs_end_transaction(trans, root);
393         return 0;
394 }
395
396 int btrfs_defrag_dirty_roots(struct btrfs_fs_info *info)
397 {
398         struct btrfs_root *gang[1];
399         struct btrfs_root *root;
400         int i;
401         int ret;
402         int err = 0;
403         u64 last = 0;
404
405         while(1) {
406                 ret = radix_tree_gang_lookup_tag(&info->fs_roots_radix,
407                                                  (void **)gang, last,
408                                                  ARRAY_SIZE(gang),
409                                                  BTRFS_ROOT_DEFRAG_TAG);
410                 if (ret == 0)
411                         break;
412                 for (i = 0; i < ret; i++) {
413                         root = gang[i];
414                         last = root->root_key.objectid + 1;
415                         btrfs_defrag_root(root, 1);
416                 }
417         }
418         btrfs_defrag_root(info->extent_root, 1);
419         return err;
420 }
421
422 static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
423                                      struct list_head *list)
424 {
425         struct dirty_root *dirty;
426         struct btrfs_trans_handle *trans;
427         unsigned long nr;
428         u64 num_bytes;
429         u64 bytes_used;
430         int ret = 0;
431         int err;
432
433         while(!list_empty(list)) {
434                 struct btrfs_root *root;
435
436                 mutex_lock(&tree_root->fs_info->fs_mutex);
437                 dirty = list_entry(list->next, struct dirty_root, list);
438                 list_del_init(&dirty->list);
439
440                 num_bytes = btrfs_root_used(&dirty->root->root_item);
441                 root = dirty->latest_root;
442                 root->fs_info->throttles++;
443
444                 while(1) {
445                         trans = btrfs_start_transaction(tree_root, 1);
446                         ret = btrfs_drop_snapshot(trans, dirty->root);
447                         if (ret != -EAGAIN) {
448                                 break;
449                         }
450
451                         err = btrfs_update_root(trans,
452                                         tree_root,
453                                         &dirty->root->root_key,
454                                         &dirty->root->root_item);
455                         if (err)
456                                 ret = err;
457                         nr = trans->blocks_used;
458                         ret = btrfs_end_transaction(trans, tree_root);
459                         BUG_ON(ret);
460                         mutex_unlock(&tree_root->fs_info->fs_mutex);
461                         btrfs_btree_balance_dirty(tree_root, nr);
462                         cond_resched();
463                         mutex_lock(&tree_root->fs_info->fs_mutex);
464                 }
465                 BUG_ON(ret);
466                 root->fs_info->throttles--;
467
468                 num_bytes -= btrfs_root_used(&dirty->root->root_item);
469                 bytes_used = btrfs_root_used(&root->root_item);
470                 if (num_bytes) {
471                         record_root_in_trans(root);
472                         btrfs_set_root_used(&root->root_item,
473                                             bytes_used - num_bytes);
474                 }
475                 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
476                 if (ret) {
477                         BUG();
478                         break;
479                 }
480                 nr = trans->blocks_used;
481                 ret = btrfs_end_transaction(trans, tree_root);
482                 BUG_ON(ret);
483
484                 free_extent_buffer(dirty->root->node);
485                 kfree(dirty->root);
486                 kfree(dirty);
487                 mutex_unlock(&tree_root->fs_info->fs_mutex);
488
489                 btrfs_btree_balance_dirty(tree_root, nr);
490                 cond_resched();
491         }
492         return ret;
493 }
494
495 int btrfs_write_ordered_inodes(struct btrfs_trans_handle *trans,
496                                 struct btrfs_root *root)
497 {
498         struct btrfs_transaction *cur_trans = trans->transaction;
499         struct inode *inode;
500         u64 root_objectid = 0;
501         u64 objectid = 0;
502         int ret;
503
504         root->fs_info->throttles++;
505         while(1) {
506                 ret = btrfs_find_first_ordered_inode(
507                                 &cur_trans->ordered_inode_tree,
508                                 &root_objectid, &objectid, &inode);
509                 if (!ret)
510                         break;
511
512                 mutex_unlock(&root->fs_info->trans_mutex);
513                 mutex_unlock(&root->fs_info->fs_mutex);
514
515                 if (S_ISREG(inode->i_mode)) {
516                         atomic_inc(&BTRFS_I(inode)->ordered_writeback);
517                         filemap_fdatawrite(inode->i_mapping);
518                         atomic_dec(&BTRFS_I(inode)->ordered_writeback);
519                 }
520                 iput(inode);
521
522                 mutex_lock(&root->fs_info->fs_mutex);
523                 mutex_lock(&root->fs_info->trans_mutex);
524         }
525         while(1) {
526                 root_objectid = 0;
527                 objectid = 0;
528                 ret = btrfs_find_del_first_ordered_inode(
529                                 &cur_trans->ordered_inode_tree,
530                                 &root_objectid, &objectid, &inode);
531                 if (!ret)
532                         break;
533                 mutex_unlock(&root->fs_info->trans_mutex);
534                 mutex_unlock(&root->fs_info->fs_mutex);
535
536                 if (S_ISREG(inode->i_mode)) {
537                         atomic_inc(&BTRFS_I(inode)->ordered_writeback);
538                         filemap_write_and_wait(inode->i_mapping);
539                         atomic_dec(&BTRFS_I(inode)->ordered_writeback);
540                 }
541                 atomic_dec(&inode->i_count);
542                 iput(inode);
543
544                 mutex_lock(&root->fs_info->fs_mutex);
545                 mutex_lock(&root->fs_info->trans_mutex);
546         }
547         root->fs_info->throttles--;
548         return 0;
549 }
550
551 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
552                                    struct btrfs_fs_info *fs_info,
553                                    struct btrfs_pending_snapshot *pending)
554 {
555         struct btrfs_key key;
556         struct btrfs_root_item *new_root_item;
557         struct btrfs_root *tree_root = fs_info->tree_root;
558         struct btrfs_root *root = pending->root;
559         struct extent_buffer *tmp;
560         int ret;
561         u64 objectid;
562
563         new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
564         if (!new_root_item) {
565                 ret = -ENOMEM;
566                 goto fail;
567         }
568         ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
569         if (ret)
570                 goto fail;
571
572         memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
573
574         key.objectid = objectid;
575         key.offset = 1;
576         btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
577
578         extent_buffer_get(root->node);
579         btrfs_cow_block(trans, root, root->node, NULL, 0, &tmp);
580         free_extent_buffer(tmp);
581
582         btrfs_copy_root(trans, root, root->node, &tmp, objectid);
583
584         btrfs_set_root_bytenr(new_root_item, tmp->start);
585         btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
586         ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
587                                 new_root_item);
588         free_extent_buffer(tmp);
589         if (ret)
590                 goto fail;
591
592         /*
593          * insert the directory item
594          */
595         key.offset = (u64)-1;
596         ret = btrfs_insert_dir_item(trans, root->fs_info->tree_root,
597                                     pending->name, strlen(pending->name),
598                                     root->fs_info->sb->s_root->d_inode->i_ino,
599                                     &key, BTRFS_FT_DIR);
600
601         if (ret)
602                 goto fail;
603
604         ret = btrfs_insert_inode_ref(trans, root->fs_info->tree_root,
605                              pending->name, strlen(pending->name), objectid,
606                              root->fs_info->sb->s_root->d_inode->i_ino);
607 fail:
608         kfree(new_root_item);
609         return ret;
610 }
611
612 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
613                                              struct btrfs_fs_info *fs_info)
614 {
615         struct btrfs_pending_snapshot *pending;
616         struct list_head *head = &trans->transaction->pending_snapshots;
617         int ret;
618
619         while(!list_empty(head)) {
620                 pending = list_entry(head->next,
621                                      struct btrfs_pending_snapshot, list);
622                 ret = create_pending_snapshot(trans, fs_info, pending);
623                 BUG_ON(ret);
624                 list_del(&pending->list);
625                 kfree(pending->name);
626                 kfree(pending);
627         }
628         return 0;
629 }
630
631 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
632                              struct btrfs_root *root)
633 {
634         unsigned long joined = 0;
635         unsigned long timeout = 1;
636         struct btrfs_transaction *cur_trans;
637         struct btrfs_transaction *prev_trans = NULL;
638         struct btrfs_root *chunk_root = root->fs_info->chunk_root;
639         struct list_head dirty_fs_roots;
640         struct extent_io_tree *pinned_copy;
641         DEFINE_WAIT(wait);
642         int ret;
643
644         INIT_LIST_HEAD(&dirty_fs_roots);
645
646         mutex_lock(&root->fs_info->trans_mutex);
647         if (trans->transaction->in_commit) {
648                 cur_trans = trans->transaction;
649                 trans->transaction->use_count++;
650                 mutex_unlock(&root->fs_info->trans_mutex);
651                 btrfs_end_transaction(trans, root);
652
653                 mutex_unlock(&root->fs_info->fs_mutex);
654                 ret = wait_for_commit(root, cur_trans);
655                 BUG_ON(ret);
656
657                 mutex_lock(&root->fs_info->trans_mutex);
658                 put_transaction(cur_trans);
659                 mutex_unlock(&root->fs_info->trans_mutex);
660
661                 mutex_lock(&root->fs_info->fs_mutex);
662                 return 0;
663         }
664
665         pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
666         if (!pinned_copy)
667                 return -ENOMEM;
668
669         extent_io_tree_init(pinned_copy,
670                              root->fs_info->btree_inode->i_mapping, GFP_NOFS);
671
672         trans->transaction->in_commit = 1;
673         cur_trans = trans->transaction;
674         if (cur_trans->list.prev != &root->fs_info->trans_list) {
675                 prev_trans = list_entry(cur_trans->list.prev,
676                                         struct btrfs_transaction, list);
677                 if (!prev_trans->commit_done) {
678                         prev_trans->use_count++;
679                         mutex_unlock(&root->fs_info->fs_mutex);
680                         mutex_unlock(&root->fs_info->trans_mutex);
681
682                         wait_for_commit(root, prev_trans);
683
684                         mutex_lock(&root->fs_info->fs_mutex);
685                         mutex_lock(&root->fs_info->trans_mutex);
686                         put_transaction(prev_trans);
687                 }
688         }
689
690         do {
691                 joined = cur_trans->num_joined;
692                 WARN_ON(cur_trans != trans->transaction);
693                 prepare_to_wait(&cur_trans->writer_wait, &wait,
694                                 TASK_UNINTERRUPTIBLE);
695
696                 if (cur_trans->num_writers > 1)
697                         timeout = MAX_SCHEDULE_TIMEOUT;
698                 else
699                         timeout = 1;
700
701                 mutex_unlock(&root->fs_info->fs_mutex);
702                 mutex_unlock(&root->fs_info->trans_mutex);
703
704                 schedule_timeout(timeout);
705
706                 mutex_lock(&root->fs_info->fs_mutex);
707                 mutex_lock(&root->fs_info->trans_mutex);
708                 finish_wait(&cur_trans->writer_wait, &wait);
709                 ret = btrfs_write_ordered_inodes(trans, root);
710
711         } while (cur_trans->num_writers > 1 ||
712                  (cur_trans->num_joined != joined));
713
714         ret = create_pending_snapshots(trans, root->fs_info);
715         BUG_ON(ret);
716
717         WARN_ON(cur_trans != trans->transaction);
718
719         ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
720                               &dirty_fs_roots);
721         BUG_ON(ret);
722
723         ret = btrfs_commit_tree_roots(trans, root);
724         BUG_ON(ret);
725
726         cur_trans = root->fs_info->running_transaction;
727         spin_lock(&root->fs_info->new_trans_lock);
728         root->fs_info->running_transaction = NULL;
729         spin_unlock(&root->fs_info->new_trans_lock);
730         btrfs_set_super_generation(&root->fs_info->super_copy,
731                                    cur_trans->transid);
732         btrfs_set_super_root(&root->fs_info->super_copy,
733                              root->fs_info->tree_root->node->start);
734         btrfs_set_super_root_level(&root->fs_info->super_copy,
735                            btrfs_header_level(root->fs_info->tree_root->node));
736
737         btrfs_set_super_chunk_root(&root->fs_info->super_copy,
738                                    chunk_root->node->start);
739         btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
740                                          btrfs_header_level(chunk_root->node));
741         write_extent_buffer(root->fs_info->sb_buffer,
742                             &root->fs_info->super_copy, 0,
743                             sizeof(root->fs_info->super_copy));
744
745         btrfs_copy_pinned(root, pinned_copy);
746
747         mutex_unlock(&root->fs_info->trans_mutex);
748         mutex_unlock(&root->fs_info->fs_mutex);
749         ret = btrfs_write_and_wait_transaction(trans, root);
750         BUG_ON(ret);
751         write_ctree_super(trans, root);
752
753         mutex_lock(&root->fs_info->fs_mutex);
754         btrfs_finish_extent_commit(trans, root, pinned_copy);
755         mutex_lock(&root->fs_info->trans_mutex);
756
757         kfree(pinned_copy);
758
759         cur_trans->commit_done = 1;
760         root->fs_info->last_trans_committed = cur_trans->transid;
761         wake_up(&cur_trans->commit_wait);
762         put_transaction(cur_trans);
763         put_transaction(cur_trans);
764
765         if (root->fs_info->closing)
766                 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
767         else
768                 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
769
770         mutex_unlock(&root->fs_info->trans_mutex);
771         kmem_cache_free(btrfs_trans_handle_cachep, trans);
772
773         if (root->fs_info->closing) {
774                 mutex_unlock(&root->fs_info->fs_mutex);
775                 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
776                 mutex_lock(&root->fs_info->fs_mutex);
777         }
778         return ret;
779 }
780
781 int btrfs_clean_old_snapshots(struct btrfs_root *root)
782 {
783         struct list_head dirty_roots;
784         INIT_LIST_HEAD(&dirty_roots);
785
786         mutex_lock(&root->fs_info->trans_mutex);
787         list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
788         mutex_unlock(&root->fs_info->trans_mutex);
789
790         if (!list_empty(&dirty_roots)) {
791                 drop_dirty_roots(root, &dirty_roots);
792         }
793         return 0;
794 }
795 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
796 void btrfs_transaction_cleaner(void *p)
797 #else
798 void btrfs_transaction_cleaner(struct work_struct *work)
799 #endif
800 {
801 #if LINUX_VERSION_CODE <= KERNEL_VERSION(2,6,18)
802         struct btrfs_fs_info *fs_info = p;
803 #else
804         struct btrfs_fs_info *fs_info = container_of(work,
805                                                      struct btrfs_fs_info,
806                                                      trans_work.work);
807
808 #endif
809         struct btrfs_root *root = fs_info->tree_root;
810         struct btrfs_transaction *cur;
811         struct btrfs_trans_handle *trans;
812         unsigned long now;
813         unsigned long delay = HZ * 30;
814         int ret;
815
816         mutex_lock(&root->fs_info->fs_mutex);
817         mutex_lock(&root->fs_info->trans_mutex);
818         cur = root->fs_info->running_transaction;
819         if (!cur) {
820                 mutex_unlock(&root->fs_info->trans_mutex);
821                 goto out;
822         }
823         now = get_seconds();
824         if (now < cur->start_time || now - cur->start_time < 30) {
825                 mutex_unlock(&root->fs_info->trans_mutex);
826                 delay = HZ * 5;
827                 goto out;
828         }
829         mutex_unlock(&root->fs_info->trans_mutex);
830         btrfs_defrag_dirty_roots(root->fs_info);
831         trans = btrfs_start_transaction(root, 1);
832         ret = btrfs_commit_transaction(trans, root);
833 out:
834         mutex_unlock(&root->fs_info->fs_mutex);
835         btrfs_clean_old_snapshots(root);
836         btrfs_transaction_queue_work(root, delay);
837 }
838
839 void btrfs_transaction_queue_work(struct btrfs_root *root, int delay)
840 {
841         queue_delayed_work(trans_wq, &root->fs_info->trans_work, delay);
842 }
843
844 void btrfs_transaction_flush_work(struct btrfs_root *root)
845 {
846         cancel_rearming_delayed_workqueue(trans_wq, &root->fs_info->trans_work);
847         flush_workqueue(trans_wq);
848 }
849
850 void __init btrfs_init_transaction_sys(void)
851 {
852         trans_wq = create_workqueue("btrfs-transaction");
853 }
854
855 void btrfs_exit_transaction_sys(void)
856 {
857         destroy_workqueue(trans_wq);
858 }
859