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ehea: Fix incomplete conversion to net_device_ops
[linux-2.6/kvm.git] / fs / btrfs / transaction.c
blob2869b3361eb6be3cf82e60ba58ce1d9191360c46
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 "ref-cache.h"
29 #include "tree-log.h"
30
31 #define BTRFS_ROOT_TRANS_TAG 0
32
33 static noinline void put_transaction(struct btrfs_transaction *transaction)
34 {
35 WARN_ON(transaction->use_count == 0);
36 transaction->use_count--;
37 if (transaction->use_count == 0) {
38 list_del_init(&transaction->list);
39 memset(transaction, 0, sizeof(*transaction));
40 kmem_cache_free(btrfs_transaction_cachep, transaction);
41 }
42 }
43
44 /*
45 * either allocate a new transaction or hop into the existing one
46 */
47 static noinline int join_transaction(struct btrfs_root *root)
48 {
49 struct btrfs_transaction *cur_trans;
50 cur_trans = root->fs_info->running_transaction;
51 if (!cur_trans) {
52 cur_trans = kmem_cache_alloc(btrfs_transaction_cachep,
53 GFP_NOFS);
54 BUG_ON(!cur_trans);
55 root->fs_info->generation++;
56 cur_trans->num_writers = 1;
57 cur_trans->num_joined = 0;
58 cur_trans->transid = root->fs_info->generation;
59 init_waitqueue_head(&cur_trans->writer_wait);
60 init_waitqueue_head(&cur_trans->commit_wait);
61 cur_trans->in_commit = 0;
62 cur_trans->blocked = 0;
63 cur_trans->use_count = 1;
64 cur_trans->commit_done = 0;
65 cur_trans->start_time = get_seconds();
66
67 cur_trans->delayed_refs.root.rb_node = NULL;
68 cur_trans->delayed_refs.num_entries = 0;
69 cur_trans->delayed_refs.num_heads_ready = 0;
70 cur_trans->delayed_refs.num_heads = 0;
71 cur_trans->delayed_refs.flushing = 0;
72 cur_trans->delayed_refs.run_delayed_start = 0;
73 spin_lock_init(&cur_trans->delayed_refs.lock);
74
75 INIT_LIST_HEAD(&cur_trans->pending_snapshots);
76 list_add_tail(&cur_trans->list, &root->fs_info->trans_list);
77 extent_io_tree_init(&cur_trans->dirty_pages,
78 root->fs_info->btree_inode->i_mapping,
79 GFP_NOFS);
80 spin_lock(&root->fs_info->new_trans_lock);
81 root->fs_info->running_transaction = cur_trans;
82 spin_unlock(&root->fs_info->new_trans_lock);
83 } else {
84 cur_trans->num_writers++;
85 cur_trans->num_joined++;
86 }
87
88 return 0;
89 }
90
91 /*
92 * this does all the record keeping required to make sure that a reference
93 * counted root is properly recorded in a given transaction. This is required
94 * to make sure the old root from before we joined the transaction is deleted
95 * when the transaction commits
96 */
97 noinline int btrfs_record_root_in_trans(struct btrfs_root *root)
98 {
99 struct btrfs_dirty_root *dirty;
100 u64 running_trans_id = root->fs_info->running_transaction->transid;
101 if (root->ref_cows && root->last_trans < running_trans_id) {
102 WARN_ON(root == root->fs_info->extent_root);
103 if (root->root_item.refs != 0) {
104 radix_tree_tag_set(&root->fs_info->fs_roots_radix,
105 (unsigned long)root->root_key.objectid,
106 BTRFS_ROOT_TRANS_TAG);
107
108 dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
109 BUG_ON(!dirty);
110 dirty->root = kmalloc(sizeof(*dirty->root), GFP_NOFS);
111 BUG_ON(!dirty->root);
112 dirty->latest_root = root;
113 INIT_LIST_HEAD(&dirty->list);
114
115 root->commit_root = btrfs_root_node(root);
116
117 memcpy(dirty->root, root, sizeof(*root));
118 spin_lock_init(&dirty->root->node_lock);
119 spin_lock_init(&dirty->root->list_lock);
120 mutex_init(&dirty->root->objectid_mutex);
121 mutex_init(&dirty->root->log_mutex);
122 INIT_LIST_HEAD(&dirty->root->dead_list);
123 dirty->root->node = root->commit_root;
124 dirty->root->commit_root = NULL;
125
126 spin_lock(&root->list_lock);
127 list_add(&dirty->root->dead_list, &root->dead_list);
128 spin_unlock(&root->list_lock);
129
130 root->dirty_root = dirty;
131 } else {
132 WARN_ON(1);
133 }
134 root->last_trans = running_trans_id;
135 }
136 return 0;
137 }
138
139 /* wait for commit against the current transaction to become unblocked
140 * when this is done, it is safe to start a new transaction, but the current
141 * transaction might not be fully on disk.
142 */
143 static void wait_current_trans(struct btrfs_root *root)
144 {
145 struct btrfs_transaction *cur_trans;
146
147 cur_trans = root->fs_info->running_transaction;
148 if (cur_trans && cur_trans->blocked) {
149 DEFINE_WAIT(wait);
150 cur_trans->use_count++;
151 while (1) {
152 prepare_to_wait(&root->fs_info->transaction_wait, &wait,
153 TASK_UNINTERRUPTIBLE);
154 if (cur_trans->blocked) {
155 mutex_unlock(&root->fs_info->trans_mutex);
156 schedule();
157 mutex_lock(&root->fs_info->trans_mutex);
158 finish_wait(&root->fs_info->transaction_wait,
159 &wait);
160 } else {
161 finish_wait(&root->fs_info->transaction_wait,
162 &wait);
163 break;
164 }
165 }
166 put_transaction(cur_trans);
167 }
168 }
169
170 static struct btrfs_trans_handle *start_transaction(struct btrfs_root *root,
171 int num_blocks, int wait)
172 {
173 struct btrfs_trans_handle *h =
174 kmem_cache_alloc(btrfs_trans_handle_cachep, GFP_NOFS);
175 int ret;
176
177 mutex_lock(&root->fs_info->trans_mutex);
178 if (!root->fs_info->log_root_recovering &&
179 ((wait == 1 && !root->fs_info->open_ioctl_trans) || wait == 2))
180 wait_current_trans(root);
181 ret = join_transaction(root);
182 BUG_ON(ret);
183
184 btrfs_record_root_in_trans(root);
185 h->transid = root->fs_info->running_transaction->transid;
186 h->transaction = root->fs_info->running_transaction;
187 h->blocks_reserved = num_blocks;
188 h->blocks_used = 0;
189 h->block_group = 0;
190 h->alloc_exclude_nr = 0;
191 h->alloc_exclude_start = 0;
192 h->delayed_ref_updates = 0;
193
194 root->fs_info->running_transaction->use_count++;
195 mutex_unlock(&root->fs_info->trans_mutex);
196 return h;
197 }
198
199 struct btrfs_trans_handle *btrfs_start_transaction(struct btrfs_root *root,
200 int num_blocks)
201 {
202 return start_transaction(root, num_blocks, 1);
203 }
204 struct btrfs_trans_handle *btrfs_join_transaction(struct btrfs_root *root,
205 int num_blocks)
206 {
207 return start_transaction(root, num_blocks, 0);
208 }
209
210 struct btrfs_trans_handle *btrfs_start_ioctl_transaction(struct btrfs_root *r,
211 int num_blocks)
212 {
213 return start_transaction(r, num_blocks, 2);
214 }
215
216 /* wait for a transaction commit to be fully complete */
217 static noinline int wait_for_commit(struct btrfs_root *root,
218 struct btrfs_transaction *commit)
219 {
220 DEFINE_WAIT(wait);
221 mutex_lock(&root->fs_info->trans_mutex);
222 while (!commit->commit_done) {
223 prepare_to_wait(&commit->commit_wait, &wait,
224 TASK_UNINTERRUPTIBLE);
225 if (commit->commit_done)
226 break;
227 mutex_unlock(&root->fs_info->trans_mutex);
228 schedule();
229 mutex_lock(&root->fs_info->trans_mutex);
230 }
231 mutex_unlock(&root->fs_info->trans_mutex);
232 finish_wait(&commit->commit_wait, &wait);
233 return 0;
234 }
235
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
277 void btrfs_throttle(struct btrfs_root *root)
278 {
279 mutex_lock(&root->fs_info->trans_mutex);
280 if (!root->fs_info->open_ioctl_trans)
281 wait_current_trans(root);
282 mutex_unlock(&root->fs_info->trans_mutex);
283 throttle_on_drops(root);
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 memset(trans, 0, sizeof(*trans));
324 kmem_cache_free(btrfs_trans_handle_cachep, trans);
325
326 if (throttle)
327 throttle_on_drops(root);
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 on disk for transaction or log commit
348 */
349 int btrfs_write_and_wait_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 while (1) {
398 ret = find_first_extent_bit(dirty_pages, 0, &start, &end,
399 EXTENT_DIRTY);
400 if (ret)
401 break;
402
403 clear_extent_dirty(dirty_pages, start, end, GFP_NOFS);
404 while (start <= end) {
405 index = start >> PAGE_CACHE_SHIFT;
406 start = (u64)(index + 1) << PAGE_CACHE_SHIFT;
407 page = find_get_page(btree_inode->i_mapping, index);
408 if (!page)
409 continue;
410 if (PageDirty(page)) {
411 btree_lock_page_hook(page);
412 wait_on_page_writeback(page);
413 err = write_one_page(page, 0);
414 if (err)
415 werr = err;
416 }
417 wait_on_page_writeback(page);
418 page_cache_release(page);
419 cond_resched();
420 }
421 }
422 if (err)
423 werr = err;
424 return werr;
425 }
426
427 int btrfs_write_and_wait_transaction(struct btrfs_trans_handle *trans,
428 struct btrfs_root *root)
429 {
430 if (!trans || !trans->transaction) {
431 struct inode *btree_inode;
432 btree_inode = root->fs_info->btree_inode;
433 return filemap_write_and_wait(btree_inode->i_mapping);
434 }
435 return btrfs_write_and_wait_marked_extents(root,
436 &trans->transaction->dirty_pages);
437 }
438
439 /*
440 * this is used to update the root pointer in the tree of tree roots.
441 *
442 * But, in the case of the extent allocation tree, updating the root
443 * pointer may allocate blocks which may change the root of the extent
444 * allocation tree.
445 *
446 * So, this loops and repeats and makes sure the cowonly root didn't
447 * change while the root pointer was being updated in the metadata.
448 */
449 static int update_cowonly_root(struct btrfs_trans_handle *trans,
450 struct btrfs_root *root)
451 {
452 int ret;
453 u64 old_root_bytenr;
454 struct btrfs_root *tree_root = root->fs_info->tree_root;
455
456 btrfs_write_dirty_block_groups(trans, root);
457
458 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
459 BUG_ON(ret);
460
461 while (1) {
462 old_root_bytenr = btrfs_root_bytenr(&root->root_item);
463 if (old_root_bytenr == root->node->start)
464 break;
465 btrfs_set_root_bytenr(&root->root_item,
466 root->node->start);
467 btrfs_set_root_level(&root->root_item,
468 btrfs_header_level(root->node));
469 btrfs_set_root_generation(&root->root_item, trans->transid);
470
471 ret = btrfs_update_root(trans, tree_root,
472 &root->root_key,
473 &root->root_item);
474 BUG_ON(ret);
475 btrfs_write_dirty_block_groups(trans, root);
476
477 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
478 BUG_ON(ret);
479 }
480 return 0;
481 }
482
483 /*
484 * update all the cowonly tree roots on disk
485 */
486 int btrfs_commit_tree_roots(struct btrfs_trans_handle *trans,
487 struct btrfs_root *root)
488 {
489 struct btrfs_fs_info *fs_info = root->fs_info;
490 struct list_head *next;
491 struct extent_buffer *eb;
492 int ret;
493
494 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
495 BUG_ON(ret);
496
497 eb = btrfs_lock_root_node(fs_info->tree_root);
498 btrfs_cow_block(trans, fs_info->tree_root, eb, NULL, 0, &eb);
499 btrfs_tree_unlock(eb);
500 free_extent_buffer(eb);
501
502 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
503 BUG_ON(ret);
504
505 while (!list_empty(&fs_info->dirty_cowonly_roots)) {
506 next = fs_info->dirty_cowonly_roots.next;
507 list_del_init(next);
508 root = list_entry(next, struct btrfs_root, dirty_list);
509
510 update_cowonly_root(trans, root);
511
512 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
513 BUG_ON(ret);
514 }
515 return 0;
516 }
517
518 /*
519 * dead roots are old snapshots that need to be deleted. This allocates
520 * a dirty root struct and adds it into the list of dead roots that need to
521 * be deleted
522 */
523 int btrfs_add_dead_root(struct btrfs_root *root, struct btrfs_root *latest)
524 {
525 struct btrfs_dirty_root *dirty;
526
527 dirty = kmalloc(sizeof(*dirty), GFP_NOFS);
528 if (!dirty)
529 return -ENOMEM;
530 dirty->root = root;
531 dirty->latest_root = latest;
532
533 mutex_lock(&root->fs_info->trans_mutex);
534 list_add(&dirty->list, &latest->fs_info->dead_roots);
535 mutex_unlock(&root->fs_info->trans_mutex);
536 return 0;
537 }
538
539 /*
540 * at transaction commit time we need to schedule the old roots for
541 * deletion via btrfs_drop_snapshot. This runs through all the
542 * reference counted roots that were modified in the current
543 * transaction and puts them into the drop list
544 */
545 static noinline int add_dirty_roots(struct btrfs_trans_handle *trans,
546 struct radix_tree_root *radix,
547 struct list_head *list)
548 {
549 struct btrfs_dirty_root *dirty;
550 struct btrfs_root *gang[8];
551 struct btrfs_root *root;
552 int i;
553 int ret;
554 int err = 0;
555 u32 refs;
556
557 while (1) {
558 ret = radix_tree_gang_lookup_tag(radix, (void **)gang, 0,
559 ARRAY_SIZE(gang),
560 BTRFS_ROOT_TRANS_TAG);
561 if (ret == 0)
562 break;
563 for (i = 0; i < ret; i++) {
564 root = gang[i];
565 radix_tree_tag_clear(radix,
566 (unsigned long)root->root_key.objectid,
567 BTRFS_ROOT_TRANS_TAG);
568
569 BUG_ON(!root->ref_tree);
570 dirty = root->dirty_root;
571
572 btrfs_free_log(trans, root);
573 btrfs_free_reloc_root(trans, root);
574
575 if (root->commit_root == root->node) {
576 WARN_ON(root->node->start !=
577 btrfs_root_bytenr(&root->root_item));
578
579 free_extent_buffer(root->commit_root);
580 root->commit_root = NULL;
581 root->dirty_root = NULL;
582
583 spin_lock(&root->list_lock);
584 list_del_init(&dirty->root->dead_list);
585 spin_unlock(&root->list_lock);
586
587 kfree(dirty->root);
588 kfree(dirty);
589
590 /* make sure to update the root on disk
591 * so we get any updates to the block used
592 * counts
593 */
594 err = btrfs_update_root(trans,
595 root->fs_info->tree_root,
596 &root->root_key,
597 &root->root_item);
598 continue;
599 }
600
601 memset(&root->root_item.drop_progress, 0,
602 sizeof(struct btrfs_disk_key));
603 root->root_item.drop_level = 0;
604 root->commit_root = NULL;
605 root->dirty_root = NULL;
606 root->root_key.offset = root->fs_info->generation;
607 btrfs_set_root_bytenr(&root->root_item,
608 root->node->start);
609 btrfs_set_root_level(&root->root_item,
610 btrfs_header_level(root->node));
611 btrfs_set_root_generation(&root->root_item,
612 root->root_key.offset);
613
614 err = btrfs_insert_root(trans, root->fs_info->tree_root,
615 &root->root_key,
616 &root->root_item);
617 if (err)
618 break;
619
620 refs = btrfs_root_refs(&dirty->root->root_item);
621 btrfs_set_root_refs(&dirty->root->root_item, refs - 1);
622 err = btrfs_update_root(trans, root->fs_info->tree_root,
623 &dirty->root->root_key,
624 &dirty->root->root_item);
625
626 BUG_ON(err);
627 if (refs == 1) {
628 list_add(&dirty->list, list);
629 } else {
630 WARN_ON(1);
631 free_extent_buffer(dirty->root->node);
632 kfree(dirty->root);
633 kfree(dirty);
634 }
635 }
636 }
637 return err;
638 }
639
640 /*
641 * defrag a given btree. If cacheonly == 1, this won't read from the disk,
642 * otherwise every leaf in the btree is read and defragged.
643 */
644 int btrfs_defrag_root(struct btrfs_root *root, int cacheonly)
645 {
646 struct btrfs_fs_info *info = root->fs_info;
647 int ret;
648 struct btrfs_trans_handle *trans;
649 unsigned long nr;
650
651 smp_mb();
652 if (root->defrag_running)
653 return 0;
654 trans = btrfs_start_transaction(root, 1);
655 while (1) {
656 root->defrag_running = 1;
657 ret = btrfs_defrag_leaves(trans, root, cacheonly);
658 nr = trans->blocks_used;
659 btrfs_end_transaction(trans, root);
660 btrfs_btree_balance_dirty(info->tree_root, nr);
661 cond_resched();
662
663 trans = btrfs_start_transaction(root, 1);
664 if (root->fs_info->closing || ret != -EAGAIN)
665 break;
666 }
667 root->defrag_running = 0;
668 smp_mb();
669 btrfs_end_transaction(trans, root);
670 return 0;
671 }
672
673 /*
674 * when dropping snapshots, we generate a ton of delayed refs, and it makes
675 * sense not to join the transaction while it is trying to flush the current
676 * queue of delayed refs out.
677 *
678 * This is used by the drop snapshot code only
679 */
680 static noinline int wait_transaction_pre_flush(struct btrfs_fs_info *info)
681 {
682 DEFINE_WAIT(wait);
683
684 mutex_lock(&info->trans_mutex);
685 while (info->running_transaction &&
686 info->running_transaction->delayed_refs.flushing) {
687 prepare_to_wait(&info->transaction_wait, &wait,
688 TASK_UNINTERRUPTIBLE);
689 mutex_unlock(&info->trans_mutex);
690 schedule();
691 mutex_lock(&info->trans_mutex);
692 finish_wait(&info->transaction_wait, &wait);
693 }
694 mutex_unlock(&info->trans_mutex);
695 return 0;
696 }
697
698 /*
699 * Given a list of roots that need to be deleted, call btrfs_drop_snapshot on
700 * all of them
701 */
702 static noinline int drop_dirty_roots(struct btrfs_root *tree_root,
703 struct list_head *list)
704 {
705 struct btrfs_dirty_root *dirty;
706 struct btrfs_trans_handle *trans;
707 unsigned long nr;
708 u64 num_bytes;
709 u64 bytes_used;
710 u64 max_useless;
711 int ret = 0;
712 int err;
713
714 while (!list_empty(list)) {
715 struct btrfs_root *root;
716
717 dirty = list_entry(list->prev, struct btrfs_dirty_root, list);
718 list_del_init(&dirty->list);
719
720 num_bytes = btrfs_root_used(&dirty->root->root_item);
721 root = dirty->latest_root;
722 atomic_inc(&root->fs_info->throttles);
723
724 while (1) {
725 /*
726 * we don't want to jump in and create a bunch of
727 * delayed refs if the transaction is starting to close
728 */
729 wait_transaction_pre_flush(tree_root->fs_info);
730 trans = btrfs_start_transaction(tree_root, 1);
731
732 /*
733 * we've joined a transaction, make sure it isn't
734 * closing right now
735 */
736 if (trans->transaction->delayed_refs.flushing) {
737 btrfs_end_transaction(trans, tree_root);
738 continue;
739 }
740
741 mutex_lock(&root->fs_info->drop_mutex);
742 ret = btrfs_drop_snapshot(trans, dirty->root);
743 if (ret != -EAGAIN)
744 break;
745 mutex_unlock(&root->fs_info->drop_mutex);
746
747 err = btrfs_update_root(trans,
748 tree_root,
749 &dirty->root->root_key,
750 &dirty->root->root_item);
751 if (err)
752 ret = err;
753 nr = trans->blocks_used;
754 ret = btrfs_end_transaction(trans, tree_root);
755 BUG_ON(ret);
756
757 btrfs_btree_balance_dirty(tree_root, nr);
758 cond_resched();
759 }
760 BUG_ON(ret);
761 atomic_dec(&root->fs_info->throttles);
762 wake_up(&root->fs_info->transaction_throttle);
763
764 num_bytes -= btrfs_root_used(&dirty->root->root_item);
765 bytes_used = btrfs_root_used(&root->root_item);
766 if (num_bytes) {
767 mutex_lock(&root->fs_info->trans_mutex);
768 btrfs_record_root_in_trans(root);
769 mutex_unlock(&root->fs_info->trans_mutex);
770 btrfs_set_root_used(&root->root_item,
771 bytes_used - num_bytes);
772 }
773
774 ret = btrfs_del_root(trans, tree_root, &dirty->root->root_key);
775 if (ret) {
776 BUG();
777 break;
778 }
779 mutex_unlock(&root->fs_info->drop_mutex);
780
781 spin_lock(&root->list_lock);
782 list_del_init(&dirty->root->dead_list);
783 if (!list_empty(&root->dead_list)) {
784 struct btrfs_root *oldest;
785 oldest = list_entry(root->dead_list.prev,
786 struct btrfs_root, dead_list);
787 max_useless = oldest->root_key.offset - 1;
788 } else {
789 max_useless = root->root_key.offset - 1;
790 }
791 spin_unlock(&root->list_lock);
792
793 nr = trans->blocks_used;
794 ret = btrfs_end_transaction(trans, tree_root);
795 BUG_ON(ret);
796
797 ret = btrfs_remove_leaf_refs(root, max_useless, 0);
798 BUG_ON(ret);
799
800 free_extent_buffer(dirty->root->node);
801 kfree(dirty->root);
802 kfree(dirty);
803
804 btrfs_btree_balance_dirty(tree_root, nr);
805 cond_resched();
806 }
807 return ret;
808 }
809
810 /*
811 * new snapshots need to be created at a very specific time in the
812 * transaction commit. This does the actual creation
813 */
814 static noinline int create_pending_snapshot(struct btrfs_trans_handle *trans,
815 struct btrfs_fs_info *fs_info,
816 struct btrfs_pending_snapshot *pending)
817 {
818 struct btrfs_key key;
819 struct btrfs_root_item *new_root_item;
820 struct btrfs_root *tree_root = fs_info->tree_root;
821 struct btrfs_root *root = pending->root;
822 struct extent_buffer *tmp;
823 struct extent_buffer *old;
824 int ret;
825 u64 objectid;
826
827 new_root_item = kmalloc(sizeof(*new_root_item), GFP_NOFS);
828 if (!new_root_item) {
829 ret = -ENOMEM;
830 goto fail;
831 }
832 ret = btrfs_find_free_objectid(trans, tree_root, 0, &objectid);
833 if (ret)
834 goto fail;
835
836 btrfs_record_root_in_trans(root);
837 btrfs_set_root_last_snapshot(&root->root_item, trans->transid);
838 memcpy(new_root_item, &root->root_item, sizeof(*new_root_item));
839
840 key.objectid = objectid;
841 key.offset = trans->transid;
842 btrfs_set_key_type(&key, BTRFS_ROOT_ITEM_KEY);
843
844 old = btrfs_lock_root_node(root);
845 btrfs_cow_block(trans, root, old, NULL, 0, &old);
846
847 btrfs_copy_root(trans, root, old, &tmp, objectid);
848 btrfs_tree_unlock(old);
849 free_extent_buffer(old);
850
851 btrfs_set_root_bytenr(new_root_item, tmp->start);
852 btrfs_set_root_level(new_root_item, btrfs_header_level(tmp));
853 btrfs_set_root_generation(new_root_item, trans->transid);
854 ret = btrfs_insert_root(trans, root->fs_info->tree_root, &key,
855 new_root_item);
856 btrfs_tree_unlock(tmp);
857 free_extent_buffer(tmp);
858 if (ret)
859 goto fail;
860
861 key.offset = (u64)-1;
862 memcpy(&pending->root_key, &key, sizeof(key));
863 fail:
864 kfree(new_root_item);
865 return ret;
866 }
867
868 static noinline int finish_pending_snapshot(struct btrfs_fs_info *fs_info,
869 struct btrfs_pending_snapshot *pending)
870 {
871 int ret;
872 int namelen;
873 u64 index = 0;
874 struct btrfs_trans_handle *trans;
875 struct inode *parent_inode;
876 struct inode *inode;
877 struct btrfs_root *parent_root;
878
879 parent_inode = pending->dentry->d_parent->d_inode;
880 parent_root = BTRFS_I(parent_inode)->root;
881 trans = btrfs_join_transaction(parent_root, 1);
882
883 /*
884 * insert the directory item
885 */
886 namelen = strlen(pending->name);
887 ret = btrfs_set_inode_index(parent_inode, &index);
888 ret = btrfs_insert_dir_item(trans, parent_root,
889 pending->name, namelen,
890 parent_inode->i_ino,
891 &pending->root_key, BTRFS_FT_DIR, index);
892
893 if (ret)
894 goto fail;
895
896 btrfs_i_size_write(parent_inode, parent_inode->i_size + namelen * 2);
897 ret = btrfs_update_inode(trans, parent_root, parent_inode);
898 BUG_ON(ret);
899
900 /* add the backref first */
901 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
902 pending->root_key.objectid,
903 BTRFS_ROOT_BACKREF_KEY,
904 parent_root->root_key.objectid,
905 parent_inode->i_ino, index, pending->name,
906 namelen);
907
908 BUG_ON(ret);
909
910 /* now add the forward ref */
911 ret = btrfs_add_root_ref(trans, parent_root->fs_info->tree_root,
912 parent_root->root_key.objectid,
913 BTRFS_ROOT_REF_KEY,
914 pending->root_key.objectid,
915 parent_inode->i_ino, index, pending->name,
916 namelen);
917
918 inode = btrfs_lookup_dentry(parent_inode, pending->dentry);
919 d_instantiate(pending->dentry, inode);
920 fail:
921 btrfs_end_transaction(trans, fs_info->fs_root);
922 return ret;
923 }
924
925 /*
926 * create all the snapshots we've scheduled for creation
927 */
928 static noinline int create_pending_snapshots(struct btrfs_trans_handle *trans,
929 struct btrfs_fs_info *fs_info)
930 {
931 struct btrfs_pending_snapshot *pending;
932 struct list_head *head = &trans->transaction->pending_snapshots;
933 int ret;
934
935 list_for_each_entry(pending, head, list) {
936 ret = create_pending_snapshot(trans, fs_info, pending);
937 BUG_ON(ret);
938 }
939 return 0;
940 }
941
942 static noinline int finish_pending_snapshots(struct btrfs_trans_handle *trans,
943 struct btrfs_fs_info *fs_info)
944 {
945 struct btrfs_pending_snapshot *pending;
946 struct list_head *head = &trans->transaction->pending_snapshots;
947 int ret;
948
949 while (!list_empty(head)) {
950 pending = list_entry(head->next,
951 struct btrfs_pending_snapshot, list);
952 ret = finish_pending_snapshot(fs_info, pending);
953 BUG_ON(ret);
954 list_del(&pending->list);
955 kfree(pending->name);
956 kfree(pending);
957 }
958 return 0;
959 }
960
961 int btrfs_commit_transaction(struct btrfs_trans_handle *trans,
962 struct btrfs_root *root)
963 {
964 unsigned long joined = 0;
965 unsigned long timeout = 1;
966 struct btrfs_transaction *cur_trans;
967 struct btrfs_transaction *prev_trans = NULL;
968 struct btrfs_root *chunk_root = root->fs_info->chunk_root;
969 struct list_head dirty_fs_roots;
970 struct extent_io_tree *pinned_copy;
971 DEFINE_WAIT(wait);
972 int ret;
973 int should_grow = 0;
974 unsigned long now = get_seconds();
975 int flush_on_commit = btrfs_test_opt(root, FLUSHONCOMMIT);
976
977 btrfs_run_ordered_operations(root, 0);
978
979 /* make a pass through all the delayed refs we have so far
980 * any runnings procs may add more while we are here
981 */
982 ret = btrfs_run_delayed_refs(trans, root, 0);
983 BUG_ON(ret);
984
985 cur_trans = trans->transaction;
986 /*
987 * set the flushing flag so procs in this transaction have to
988 * start sending their work down.
989 */
990 cur_trans->delayed_refs.flushing = 1;
991
992 ret = btrfs_run_delayed_refs(trans, root, 0);
993 BUG_ON(ret);
994
995 mutex_lock(&root->fs_info->trans_mutex);
996 INIT_LIST_HEAD(&dirty_fs_roots);
997 if (cur_trans->in_commit) {
998 cur_trans->use_count++;
999 mutex_unlock(&root->fs_info->trans_mutex);
1000 btrfs_end_transaction(trans, root);
1001
1002 ret = wait_for_commit(root, cur_trans);
1003 BUG_ON(ret);
1004
1005 mutex_lock(&root->fs_info->trans_mutex);
1006 put_transaction(cur_trans);
1007 mutex_unlock(&root->fs_info->trans_mutex);
1008
1009 return 0;
1010 }
1011
1012 pinned_copy = kmalloc(sizeof(*pinned_copy), GFP_NOFS);
1013 if (!pinned_copy)
1014 return -ENOMEM;
1015
1016 extent_io_tree_init(pinned_copy,
1017 root->fs_info->btree_inode->i_mapping, GFP_NOFS);
1018
1019 trans->transaction->in_commit = 1;
1020 trans->transaction->blocked = 1;
1021 if (cur_trans->list.prev != &root->fs_info->trans_list) {
1022 prev_trans = list_entry(cur_trans->list.prev,
1023 struct btrfs_transaction, list);
1024 if (!prev_trans->commit_done) {
1025 prev_trans->use_count++;
1026 mutex_unlock(&root->fs_info->trans_mutex);
1027
1028 wait_for_commit(root, prev_trans);
1029
1030 mutex_lock(&root->fs_info->trans_mutex);
1031 put_transaction(prev_trans);
1032 }
1033 }
1034
1035 if (now < cur_trans->start_time || now - cur_trans->start_time < 1)
1036 should_grow = 1;
1037
1038 do {
1039 int snap_pending = 0;
1040 joined = cur_trans->num_joined;
1041 if (!list_empty(&trans->transaction->pending_snapshots))
1042 snap_pending = 1;
1043
1044 WARN_ON(cur_trans != trans->transaction);
1045 prepare_to_wait(&cur_trans->writer_wait, &wait,
1046 TASK_UNINTERRUPTIBLE);
1047
1048 if (cur_trans->num_writers > 1)
1049 timeout = MAX_SCHEDULE_TIMEOUT;
1050 else if (should_grow)
1051 timeout = 1;
1052
1053 mutex_unlock(&root->fs_info->trans_mutex);
1054
1055 if (flush_on_commit || snap_pending) {
1056 if (flush_on_commit)
1057 btrfs_start_delalloc_inodes(root);
1058 ret = btrfs_wait_ordered_extents(root, 1);
1059 BUG_ON(ret);
1060 }
1061
1062 /*
1063 * rename don't use btrfs_join_transaction, so, once we
1064 * set the transaction to blocked above, we aren't going
1065 * to get any new ordered operations. We can safely run
1066 * it here and no for sure that nothing new will be added
1067 * to the list
1068 */
1069 btrfs_run_ordered_operations(root, 1);
1070
1071 smp_mb();
1072 if (cur_trans->num_writers > 1 || should_grow)
1073 schedule_timeout(timeout);
1074
1075 mutex_lock(&root->fs_info->trans_mutex);
1076 finish_wait(&cur_trans->writer_wait, &wait);
1077 } while (cur_trans->num_writers > 1 ||
1078 (should_grow && cur_trans->num_joined != joined));
1079
1080 ret = create_pending_snapshots(trans, root->fs_info);
1081 BUG_ON(ret);
1082
1083 ret = btrfs_run_delayed_refs(trans, root, (unsigned long)-1);
1084 BUG_ON(ret);
1085
1086 WARN_ON(cur_trans != trans->transaction);
1087
1088 /* btrfs_commit_tree_roots is responsible for getting the
1089 * various roots consistent with each other. Every pointer
1090 * in the tree of tree roots has to point to the most up to date
1091 * root for every subvolume and other tree. So, we have to keep
1092 * the tree logging code from jumping in and changing any
1093 * of the trees.
1094 *
1095 * At this point in the commit, there can't be any tree-log
1096 * writers, but a little lower down we drop the trans mutex
1097 * and let new people in. By holding the tree_log_mutex
1098 * from now until after the super is written, we avoid races
1099 * with the tree-log code.
1100 */
1101 mutex_lock(&root->fs_info->tree_log_mutex);
1102 /*
1103 * keep tree reloc code from adding new reloc trees
1104 */
1105 mutex_lock(&root->fs_info->tree_reloc_mutex);
1106
1107
1108 ret = add_dirty_roots(trans, &root->fs_info->fs_roots_radix,
1109 &dirty_fs_roots);
1110 BUG_ON(ret);
1111
1112 /* add_dirty_roots gets rid of all the tree log roots, it is now
1113 * safe to free the root of tree log roots
1114 */
1115 btrfs_free_log_root_tree(trans, root->fs_info);
1116
1117 ret = btrfs_commit_tree_roots(trans, root);
1118 BUG_ON(ret);
1119
1120 cur_trans = root->fs_info->running_transaction;
1121 spin_lock(&root->fs_info->new_trans_lock);
1122 root->fs_info->running_transaction = NULL;
1123 spin_unlock(&root->fs_info->new_trans_lock);
1124 btrfs_set_super_generation(&root->fs_info->super_copy,
1125 cur_trans->transid);
1126 btrfs_set_super_root(&root->fs_info->super_copy,
1127 root->fs_info->tree_root->node->start);
1128 btrfs_set_super_root_level(&root->fs_info->super_copy,
1129 btrfs_header_level(root->fs_info->tree_root->node));
1130
1131 btrfs_set_super_chunk_root(&root->fs_info->super_copy,
1132 chunk_root->node->start);
1133 btrfs_set_super_chunk_root_level(&root->fs_info->super_copy,
1134 btrfs_header_level(chunk_root->node));
1135 btrfs_set_super_chunk_root_generation(&root->fs_info->super_copy,
1136 btrfs_header_generation(chunk_root->node));
1137
1138 if (!root->fs_info->log_root_recovering) {
1139 btrfs_set_super_log_root(&root->fs_info->super_copy, 0);
1140 btrfs_set_super_log_root_level(&root->fs_info->super_copy, 0);
1141 }
1142
1143 memcpy(&root->fs_info->super_for_commit, &root->fs_info->super_copy,
1144 sizeof(root->fs_info->super_copy));
1145
1146 btrfs_copy_pinned(root, pinned_copy);
1147
1148 trans->transaction->blocked = 0;
1149
1150 wake_up(&root->fs_info->transaction_throttle);
1151 wake_up(&root->fs_info->transaction_wait);
1152
1153 mutex_unlock(&root->fs_info->trans_mutex);
1154 ret = btrfs_write_and_wait_transaction(trans, root);
1155 BUG_ON(ret);
1156 write_ctree_super(trans, root, 0);
1157
1158 /*
1159 * the super is written, we can safely allow the tree-loggers
1160 * to go about their business
1161 */
1162 mutex_unlock(&root->fs_info->tree_log_mutex);
1163
1164 btrfs_finish_extent_commit(trans, root, pinned_copy);
1165 kfree(pinned_copy);
1166
1167 btrfs_drop_dead_reloc_roots(root);
1168 mutex_unlock(&root->fs_info->tree_reloc_mutex);
1169
1170 /* do the directory inserts of any pending snapshot creations */
1171 finish_pending_snapshots(trans, root->fs_info);
1172
1173 mutex_lock(&root->fs_info->trans_mutex);
1174
1175 cur_trans->commit_done = 1;
1176
1177 root->fs_info->last_trans_committed = cur_trans->transid;
1178 wake_up(&cur_trans->commit_wait);
1179
1180 put_transaction(cur_trans);
1181 put_transaction(cur_trans);
1182
1183 list_splice_init(&dirty_fs_roots, &root->fs_info->dead_roots);
1184 if (root->fs_info->closing)
1185 list_splice_init(&root->fs_info->dead_roots, &dirty_fs_roots);
1186
1187 mutex_unlock(&root->fs_info->trans_mutex);
1188
1189 kmem_cache_free(btrfs_trans_handle_cachep, trans);
1190
1191 if (root->fs_info->closing)
1192 drop_dirty_roots(root->fs_info->tree_root, &dirty_fs_roots);
1193 return ret;
1194 }
1195
1196 /*
1197 * interface function to delete all the snapshots we have scheduled for deletion
1198 */
1199 int btrfs_clean_old_snapshots(struct btrfs_root *root)
1200 {
1201 struct list_head dirty_roots;
1202 INIT_LIST_HEAD(&dirty_roots);
1203 again:
1204 mutex_lock(&root->fs_info->trans_mutex);
1205 list_splice_init(&root->fs_info->dead_roots, &dirty_roots);
1206 mutex_unlock(&root->fs_info->trans_mutex);
1207
1208 if (!list_empty(&dirty_roots)) {
1209 drop_dirty_roots(root, &dirty_roots);
1210 goto again;
1211 }
1212 return 0;
1213 }
kernel-based virtual machine