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aufs: possible bugfix, allow the nested aufsd between several aufs mounts
[zen-stable.git] / fs / btrfs / relocation.c
blob8c1aae2c845d49960fe352c809033f1bdf5ffb74
1 /*
2 * Copyright (C) 2009 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/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97
98 struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
108 struct list_head pending[BTRFS_MAX_LEVEL];
109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
120 };
121
122 /*
123 * map address of tree root to tree
124 */
125 struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129 };
130
131 struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134 };
135
136 /*
137 * present a tree block to process
138 */
139 struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145 };
146
147 #define MAX_EXTENTS 128
148
149 struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154 };
155
156 struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
180 u64 search_start;
181 u64 extents_found;
182
183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
186 unsigned int found_file_extent:1;
187 unsigned int commit_transaction:1;
188 };
189
190 /* stages of data relocation */
191 #define MOVE_DATA_EXTENTS 0
192 #define UPDATE_DATA_PTRS 1
193
194 static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196 static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
198
199 static void mapping_tree_init(struct mapping_tree *tree)
200 {
201 tree->rb_root = RB_ROOT;
202 spin_lock_init(&tree->lock);
203 }
204
205 static void backref_cache_init(struct backref_cache *cache)
206 {
207 int i;
208 cache->rb_root = RB_ROOT;
209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214 }
215
216 static void backref_cache_cleanup(struct backref_cache *cache)
217 {
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242 }
243
244 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245 {
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257 }
258
259 static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261 {
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266 }
267
268 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269 {
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
276 }
277
278 static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
280 {
281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
285 }
286
287 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289 {
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309 }
310
311 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312 {
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327 }
328
329 /*
330 * walk up backref nodes until reach node presents tree root
331 */
332 static struct backref_node *walk_up_backref(struct backref_node *node,
333 struct backref_edge *edges[],
334 int *index)
335 {
336 struct backref_edge *edge;
337 int idx = *index;
338
339 while (!list_empty(&node->upper)) {
340 edge = list_entry(node->upper.next,
341 struct backref_edge, list[LOWER]);
342 edges[idx++] = edge;
343 node = edge->node[UPPER];
344 }
345 BUG_ON(node->detached);
346 *index = idx;
347 return node;
348 }
349
350 /*
351 * walk down backref nodes to find start of next reference path
352 */
353 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
354 int *index)
355 {
356 struct backref_edge *edge;
357 struct backref_node *lower;
358 int idx = *index;
359
360 while (idx > 0) {
361 edge = edges[idx - 1];
362 lower = edge->node[LOWER];
363 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
364 idx--;
365 continue;
366 }
367 edge = list_entry(edge->list[LOWER].next,
368 struct backref_edge, list[LOWER]);
369 edges[idx - 1] = edge;
370 *index = idx;
371 return edge->node[UPPER];
372 }
373 *index = 0;
374 return NULL;
375 }
376
377 static void unlock_node_buffer(struct backref_node *node)
378 {
379 if (node->locked) {
380 btrfs_tree_unlock(node->eb);
381 node->locked = 0;
382 }
383 }
384
385 static void drop_node_buffer(struct backref_node *node)
386 {
387 if (node->eb) {
388 unlock_node_buffer(node);
389 free_extent_buffer(node->eb);
390 node->eb = NULL;
391 }
392 }
393
394 static void drop_backref_node(struct backref_cache *tree,
395 struct backref_node *node)
396 {
397 BUG_ON(!list_empty(&node->upper));
398
399 drop_node_buffer(node);
400 list_del(&node->list);
401 list_del(&node->lower);
402 if (!RB_EMPTY_NODE(&node->rb_node))
403 rb_erase(&node->rb_node, &tree->rb_root);
404 free_backref_node(tree, node);
405 }
406
407 /*
408 * remove a backref node from the backref cache
409 */
410 static void remove_backref_node(struct backref_cache *cache,
411 struct backref_node *node)
412 {
413 struct backref_node *upper;
414 struct backref_edge *edge;
415
416 if (!node)
417 return;
418
419 BUG_ON(!node->lowest && !node->detached);
420 while (!list_empty(&node->upper)) {
421 edge = list_entry(node->upper.next, struct backref_edge,
422 list[LOWER]);
423 upper = edge->node[UPPER];
424 list_del(&edge->list[LOWER]);
425 list_del(&edge->list[UPPER]);
426 free_backref_edge(cache, edge);
427
428 if (RB_EMPTY_NODE(&upper->rb_node)) {
429 BUG_ON(!list_empty(&node->upper));
430 drop_backref_node(cache, node);
431 node = upper;
432 node->lowest = 1;
433 continue;
434 }
435 /*
436 * add the node to leaf node list if no other
437 * child block cached.
438 */
439 if (list_empty(&upper->lower)) {
440 list_add_tail(&upper->lower, &cache->leaves);
441 upper->lowest = 1;
442 }
443 }
444
445 drop_backref_node(cache, node);
446 }
447
448 static void update_backref_node(struct backref_cache *cache,
449 struct backref_node *node, u64 bytenr)
450 {
451 struct rb_node *rb_node;
452 rb_erase(&node->rb_node, &cache->rb_root);
453 node->bytenr = bytenr;
454 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
455 BUG_ON(rb_node);
456 }
457
458 /*
459 * update backref cache after a transaction commit
460 */
461 static int update_backref_cache(struct btrfs_trans_handle *trans,
462 struct backref_cache *cache)
463 {
464 struct backref_node *node;
465 int level = 0;
466
467 if (cache->last_trans == 0) {
468 cache->last_trans = trans->transid;
469 return 0;
470 }
471
472 if (cache->last_trans == trans->transid)
473 return 0;
474
475 /*
476 * detached nodes are used to avoid unnecessary backref
477 * lookup. transaction commit changes the extent tree.
478 * so the detached nodes are no longer useful.
479 */
480 while (!list_empty(&cache->detached)) {
481 node = list_entry(cache->detached.next,
482 struct backref_node, list);
483 remove_backref_node(cache, node);
484 }
485
486 while (!list_empty(&cache->changed)) {
487 node = list_entry(cache->changed.next,
488 struct backref_node, list);
489 list_del_init(&node->list);
490 BUG_ON(node->pending);
491 update_backref_node(cache, node, node->new_bytenr);
492 }
493
494 /*
495 * some nodes can be left in the pending list if there were
496 * errors during processing the pending nodes.
497 */
498 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
499 list_for_each_entry(node, &cache->pending[level], list) {
500 BUG_ON(!node->pending);
501 if (node->bytenr == node->new_bytenr)
502 continue;
503 update_backref_node(cache, node, node->new_bytenr);
504 }
505 }
506
507 cache->last_trans = 0;
508 return 1;
509 }
510
511
512 static int should_ignore_root(struct btrfs_root *root)
513 {
514 struct btrfs_root *reloc_root;
515
516 if (!root->ref_cows)
517 return 0;
518
519 reloc_root = root->reloc_root;
520 if (!reloc_root)
521 return 0;
522
523 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
524 root->fs_info->running_transaction->transid - 1)
525 return 0;
526 /*
527 * if there is reloc tree and it was created in previous
528 * transaction backref lookup can find the reloc tree,
529 * so backref node for the fs tree root is useless for
530 * relocation.
531 */
532 return 1;
533 }
534 /*
535 * find reloc tree by address of tree root
536 */
537 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
538 u64 bytenr)
539 {
540 struct rb_node *rb_node;
541 struct mapping_node *node;
542 struct btrfs_root *root = NULL;
543
544 spin_lock(&rc->reloc_root_tree.lock);
545 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
546 if (rb_node) {
547 node = rb_entry(rb_node, struct mapping_node, rb_node);
548 root = (struct btrfs_root *)node->data;
549 }
550 spin_unlock(&rc->reloc_root_tree.lock);
551 return root;
552 }
553
554 static int is_cowonly_root(u64 root_objectid)
555 {
556 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
557 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
558 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
559 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
560 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
561 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
562 return 1;
563 return 0;
564 }
565
566 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
567 u64 root_objectid)
568 {
569 struct btrfs_key key;
570
571 key.objectid = root_objectid;
572 key.type = BTRFS_ROOT_ITEM_KEY;
573 if (is_cowonly_root(root_objectid))
574 key.offset = 0;
575 else
576 key.offset = (u64)-1;
577
578 return btrfs_read_fs_root_no_name(fs_info, &key);
579 }
580
581 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
582 static noinline_for_stack
583 struct btrfs_root *find_tree_root(struct reloc_control *rc,
584 struct extent_buffer *leaf,
585 struct btrfs_extent_ref_v0 *ref0)
586 {
587 struct btrfs_root *root;
588 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
589 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
590
591 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
592
593 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
594 BUG_ON(IS_ERR(root));
595
596 if (root->ref_cows &&
597 generation != btrfs_root_generation(&root->root_item))
598 return NULL;
599
600 return root;
601 }
602 #endif
603
604 static noinline_for_stack
605 int find_inline_backref(struct extent_buffer *leaf, int slot,
606 unsigned long *ptr, unsigned long *end)
607 {
608 struct btrfs_extent_item *ei;
609 struct btrfs_tree_block_info *bi;
610 u32 item_size;
611
612 item_size = btrfs_item_size_nr(leaf, slot);
613 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
614 if (item_size < sizeof(*ei)) {
615 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
616 return 1;
617 }
618 #endif
619 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
620 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
621 BTRFS_EXTENT_FLAG_TREE_BLOCK));
622
623 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
624 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
625 return 1;
626 }
627
628 bi = (struct btrfs_tree_block_info *)(ei + 1);
629 *ptr = (unsigned long)(bi + 1);
630 *end = (unsigned long)ei + item_size;
631 return 0;
632 }
633
634 /*
635 * build backref tree for a given tree block. root of the backref tree
636 * corresponds the tree block, leaves of the backref tree correspond
637 * roots of b-trees that reference the tree block.
638 *
639 * the basic idea of this function is check backrefs of a given block
640 * to find upper level blocks that refernece the block, and then check
641 * bakcrefs of these upper level blocks recursively. the recursion stop
642 * when tree root is reached or backrefs for the block is cached.
643 *
644 * NOTE: if we find backrefs for a block are cached, we know backrefs
645 * for all upper level blocks that directly/indirectly reference the
646 * block are also cached.
647 */
648 static noinline_for_stack
649 struct backref_node *build_backref_tree(struct reloc_control *rc,
650 struct btrfs_key *node_key,
651 int level, u64 bytenr)
652 {
653 struct backref_cache *cache = &rc->backref_cache;
654 struct btrfs_path *path1;
655 struct btrfs_path *path2;
656 struct extent_buffer *eb;
657 struct btrfs_root *root;
658 struct backref_node *cur;
659 struct backref_node *upper;
660 struct backref_node *lower;
661 struct backref_node *node = NULL;
662 struct backref_node *exist = NULL;
663 struct backref_edge *edge;
664 struct rb_node *rb_node;
665 struct btrfs_key key;
666 unsigned long end;
667 unsigned long ptr;
668 LIST_HEAD(list);
669 LIST_HEAD(useless);
670 int cowonly;
671 int ret;
672 int err = 0;
673
674 path1 = btrfs_alloc_path();
675 path2 = btrfs_alloc_path();
676 if (!path1 || !path2) {
677 err = -ENOMEM;
678 goto out;
679 }
680 path1->reada = 1;
681 path2->reada = 2;
682
683 node = alloc_backref_node(cache);
684 if (!node) {
685 err = -ENOMEM;
686 goto out;
687 }
688
689 node->bytenr = bytenr;
690 node->level = level;
691 node->lowest = 1;
692 cur = node;
693 again:
694 end = 0;
695 ptr = 0;
696 key.objectid = cur->bytenr;
697 key.type = BTRFS_EXTENT_ITEM_KEY;
698 key.offset = (u64)-1;
699
700 path1->search_commit_root = 1;
701 path1->skip_locking = 1;
702 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
703 0, 0);
704 if (ret < 0) {
705 err = ret;
706 goto out;
707 }
708 BUG_ON(!ret || !path1->slots[0]);
709
710 path1->slots[0]--;
711
712 WARN_ON(cur->checked);
713 if (!list_empty(&cur->upper)) {
714 /*
715 * the backref was added previously when processing
716 * backref of type BTRFS_TREE_BLOCK_REF_KEY
717 */
718 BUG_ON(!list_is_singular(&cur->upper));
719 edge = list_entry(cur->upper.next, struct backref_edge,
720 list[LOWER]);
721 BUG_ON(!list_empty(&edge->list[UPPER]));
722 exist = edge->node[UPPER];
723 /*
724 * add the upper level block to pending list if we need
725 * check its backrefs
726 */
727 if (!exist->checked)
728 list_add_tail(&edge->list[UPPER], &list);
729 } else {
730 exist = NULL;
731 }
732
733 while (1) {
734 cond_resched();
735 eb = path1->nodes[0];
736
737 if (ptr >= end) {
738 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
739 ret = btrfs_next_leaf(rc->extent_root, path1);
740 if (ret < 0) {
741 err = ret;
742 goto out;
743 }
744 if (ret > 0)
745 break;
746 eb = path1->nodes[0];
747 }
748
749 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
750 if (key.objectid != cur->bytenr) {
751 WARN_ON(exist);
752 break;
753 }
754
755 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
756 ret = find_inline_backref(eb, path1->slots[0],
757 &ptr, &end);
758 if (ret)
759 goto next;
760 }
761 }
762
763 if (ptr < end) {
764 /* update key for inline back ref */
765 struct btrfs_extent_inline_ref *iref;
766 iref = (struct btrfs_extent_inline_ref *)ptr;
767 key.type = btrfs_extent_inline_ref_type(eb, iref);
768 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
769 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
770 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
771 }
772
773 if (exist &&
774 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
775 exist->owner == key.offset) ||
776 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
777 exist->bytenr == key.offset))) {
778 exist = NULL;
779 goto next;
780 }
781
782 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
783 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
784 key.type == BTRFS_EXTENT_REF_V0_KEY) {
785 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
786 struct btrfs_extent_ref_v0 *ref0;
787 ref0 = btrfs_item_ptr(eb, path1->slots[0],
788 struct btrfs_extent_ref_v0);
789 if (key.objectid == key.offset) {
790 root = find_tree_root(rc, eb, ref0);
791 if (root && !should_ignore_root(root))
792 cur->root = root;
793 else
794 list_add(&cur->list, &useless);
795 break;
796 }
797 if (is_cowonly_root(btrfs_ref_root_v0(eb,
798 ref0)))
799 cur->cowonly = 1;
800 }
801 #else
802 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
803 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
804 #endif
805 if (key.objectid == key.offset) {
806 /*
807 * only root blocks of reloc trees use
808 * backref of this type.
809 */
810 root = find_reloc_root(rc, cur->bytenr);
811 BUG_ON(!root);
812 cur->root = root;
813 break;
814 }
815
816 edge = alloc_backref_edge(cache);
817 if (!edge) {
818 err = -ENOMEM;
819 goto out;
820 }
821 rb_node = tree_search(&cache->rb_root, key.offset);
822 if (!rb_node) {
823 upper = alloc_backref_node(cache);
824 if (!upper) {
825 free_backref_edge(cache, edge);
826 err = -ENOMEM;
827 goto out;
828 }
829 upper->bytenr = key.offset;
830 upper->level = cur->level + 1;
831 /*
832 * backrefs for the upper level block isn't
833 * cached, add the block to pending list
834 */
835 list_add_tail(&edge->list[UPPER], &list);
836 } else {
837 upper = rb_entry(rb_node, struct backref_node,
838 rb_node);
839 BUG_ON(!upper->checked);
840 INIT_LIST_HEAD(&edge->list[UPPER]);
841 }
842 list_add_tail(&edge->list[LOWER], &cur->upper);
843 edge->node[LOWER] = cur;
844 edge->node[UPPER] = upper;
845
846 goto next;
847 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
848 goto next;
849 }
850
851 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
852 root = read_fs_root(rc->extent_root->fs_info, key.offset);
853 if (IS_ERR(root)) {
854 err = PTR_ERR(root);
855 goto out;
856 }
857
858 if (!root->ref_cows)
859 cur->cowonly = 1;
860
861 if (btrfs_root_level(&root->root_item) == cur->level) {
862 /* tree root */
863 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
864 cur->bytenr);
865 if (should_ignore_root(root))
866 list_add(&cur->list, &useless);
867 else
868 cur->root = root;
869 break;
870 }
871
872 level = cur->level + 1;
873
874 /*
875 * searching the tree to find upper level blocks
876 * reference the block.
877 */
878 path2->search_commit_root = 1;
879 path2->skip_locking = 1;
880 path2->lowest_level = level;
881 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
882 path2->lowest_level = 0;
883 if (ret < 0) {
884 err = ret;
885 goto out;
886 }
887 if (ret > 0 && path2->slots[level] > 0)
888 path2->slots[level]--;
889
890 eb = path2->nodes[level];
891 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
892 cur->bytenr);
893
894 lower = cur;
895 for (; level < BTRFS_MAX_LEVEL; level++) {
896 if (!path2->nodes[level]) {
897 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
898 lower->bytenr);
899 if (should_ignore_root(root))
900 list_add(&lower->list, &useless);
901 else
902 lower->root = root;
903 break;
904 }
905
906 edge = alloc_backref_edge(cache);
907 if (!edge) {
908 err = -ENOMEM;
909 goto out;
910 }
911
912 eb = path2->nodes[level];
913 rb_node = tree_search(&cache->rb_root, eb->start);
914 if (!rb_node) {
915 upper = alloc_backref_node(cache);
916 if (!upper) {
917 free_backref_edge(cache, edge);
918 err = -ENOMEM;
919 goto out;
920 }
921 upper->bytenr = eb->start;
922 upper->owner = btrfs_header_owner(eb);
923 upper->level = lower->level + 1;
924 if (!root->ref_cows)
925 upper->cowonly = 1;
926
927 /*
928 * if we know the block isn't shared
929 * we can void checking its backrefs.
930 */
931 if (btrfs_block_can_be_shared(root, eb))
932 upper->checked = 0;
933 else
934 upper->checked = 1;
935
936 /*
937 * add the block to pending list if we
938 * need check its backrefs. only block
939 * at 'cur->level + 1' is added to the
940 * tail of pending list. this guarantees
941 * we check backrefs from lower level
942 * blocks to upper level blocks.
943 */
944 if (!upper->checked &&
945 level == cur->level + 1) {
946 list_add_tail(&edge->list[UPPER],
947 &list);
948 } else
949 INIT_LIST_HEAD(&edge->list[UPPER]);
950 } else {
951 upper = rb_entry(rb_node, struct backref_node,
952 rb_node);
953 BUG_ON(!upper->checked);
954 INIT_LIST_HEAD(&edge->list[UPPER]);
955 if (!upper->owner)
956 upper->owner = btrfs_header_owner(eb);
957 }
958 list_add_tail(&edge->list[LOWER], &lower->upper);
959 edge->node[LOWER] = lower;
960 edge->node[UPPER] = upper;
961
962 if (rb_node)
963 break;
964 lower = upper;
965 upper = NULL;
966 }
967 btrfs_release_path(path2);
968 next:
969 if (ptr < end) {
970 ptr += btrfs_extent_inline_ref_size(key.type);
971 if (ptr >= end) {
972 WARN_ON(ptr > end);
973 ptr = 0;
974 end = 0;
975 }
976 }
977 if (ptr >= end)
978 path1->slots[0]++;
979 }
980 btrfs_release_path(path1);
981
982 cur->checked = 1;
983 WARN_ON(exist);
984
985 /* the pending list isn't empty, take the first block to process */
986 if (!list_empty(&list)) {
987 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
988 list_del_init(&edge->list[UPPER]);
989 cur = edge->node[UPPER];
990 goto again;
991 }
992
993 /*
994 * everything goes well, connect backref nodes and insert backref nodes
995 * into the cache.
996 */
997 BUG_ON(!node->checked);
998 cowonly = node->cowonly;
999 if (!cowonly) {
1000 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1001 &node->rb_node);
1002 BUG_ON(rb_node);
1003 list_add_tail(&node->lower, &cache->leaves);
1004 }
1005
1006 list_for_each_entry(edge, &node->upper, list[LOWER])
1007 list_add_tail(&edge->list[UPPER], &list);
1008
1009 while (!list_empty(&list)) {
1010 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1011 list_del_init(&edge->list[UPPER]);
1012 upper = edge->node[UPPER];
1013 if (upper->detached) {
1014 list_del(&edge->list[LOWER]);
1015 lower = edge->node[LOWER];
1016 free_backref_edge(cache, edge);
1017 if (list_empty(&lower->upper))
1018 list_add(&lower->list, &useless);
1019 continue;
1020 }
1021
1022 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1023 if (upper->lowest) {
1024 list_del_init(&upper->lower);
1025 upper->lowest = 0;
1026 }
1027
1028 list_add_tail(&edge->list[UPPER], &upper->lower);
1029 continue;
1030 }
1031
1032 BUG_ON(!upper->checked);
1033 BUG_ON(cowonly != upper->cowonly);
1034 if (!cowonly) {
1035 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1036 &upper->rb_node);
1037 BUG_ON(rb_node);
1038 }
1039
1040 list_add_tail(&edge->list[UPPER], &upper->lower);
1041
1042 list_for_each_entry(edge, &upper->upper, list[LOWER])
1043 list_add_tail(&edge->list[UPPER], &list);
1044 }
1045 /*
1046 * process useless backref nodes. backref nodes for tree leaves
1047 * are deleted from the cache. backref nodes for upper level
1048 * tree blocks are left in the cache to avoid unnecessary backref
1049 * lookup.
1050 */
1051 while (!list_empty(&useless)) {
1052 upper = list_entry(useless.next, struct backref_node, list);
1053 list_del_init(&upper->list);
1054 BUG_ON(!list_empty(&upper->upper));
1055 if (upper == node)
1056 node = NULL;
1057 if (upper->lowest) {
1058 list_del_init(&upper->lower);
1059 upper->lowest = 0;
1060 }
1061 while (!list_empty(&upper->lower)) {
1062 edge = list_entry(upper->lower.next,
1063 struct backref_edge, list[UPPER]);
1064 list_del(&edge->list[UPPER]);
1065 list_del(&edge->list[LOWER]);
1066 lower = edge->node[LOWER];
1067 free_backref_edge(cache, edge);
1068
1069 if (list_empty(&lower->upper))
1070 list_add(&lower->list, &useless);
1071 }
1072 __mark_block_processed(rc, upper);
1073 if (upper->level > 0) {
1074 list_add(&upper->list, &cache->detached);
1075 upper->detached = 1;
1076 } else {
1077 rb_erase(&upper->rb_node, &cache->rb_root);
1078 free_backref_node(cache, upper);
1079 }
1080 }
1081 out:
1082 btrfs_free_path(path1);
1083 btrfs_free_path(path2);
1084 if (err) {
1085 while (!list_empty(&useless)) {
1086 lower = list_entry(useless.next,
1087 struct backref_node, upper);
1088 list_del_init(&lower->upper);
1089 }
1090 upper = node;
1091 INIT_LIST_HEAD(&list);
1092 while (upper) {
1093 if (RB_EMPTY_NODE(&upper->rb_node)) {
1094 list_splice_tail(&upper->upper, &list);
1095 free_backref_node(cache, upper);
1096 }
1097
1098 if (list_empty(&list))
1099 break;
1100
1101 edge = list_entry(list.next, struct backref_edge,
1102 list[LOWER]);
1103 list_del(&edge->list[LOWER]);
1104 upper = edge->node[UPPER];
1105 free_backref_edge(cache, edge);
1106 }
1107 return ERR_PTR(err);
1108 }
1109 BUG_ON(node && node->detached);
1110 return node;
1111 }
1112
1113 /*
1114 * helper to add backref node for the newly created snapshot.
1115 * the backref node is created by cloning backref node that
1116 * corresponds to root of source tree
1117 */
1118 static int clone_backref_node(struct btrfs_trans_handle *trans,
1119 struct reloc_control *rc,
1120 struct btrfs_root *src,
1121 struct btrfs_root *dest)
1122 {
1123 struct btrfs_root *reloc_root = src->reloc_root;
1124 struct backref_cache *cache = &rc->backref_cache;
1125 struct backref_node *node = NULL;
1126 struct backref_node *new_node;
1127 struct backref_edge *edge;
1128 struct backref_edge *new_edge;
1129 struct rb_node *rb_node;
1130
1131 if (cache->last_trans > 0)
1132 update_backref_cache(trans, cache);
1133
1134 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1135 if (rb_node) {
1136 node = rb_entry(rb_node, struct backref_node, rb_node);
1137 if (node->detached)
1138 node = NULL;
1139 else
1140 BUG_ON(node->new_bytenr != reloc_root->node->start);
1141 }
1142
1143 if (!node) {
1144 rb_node = tree_search(&cache->rb_root,
1145 reloc_root->commit_root->start);
1146 if (rb_node) {
1147 node = rb_entry(rb_node, struct backref_node,
1148 rb_node);
1149 BUG_ON(node->detached);
1150 }
1151 }
1152
1153 if (!node)
1154 return 0;
1155
1156 new_node = alloc_backref_node(cache);
1157 if (!new_node)
1158 return -ENOMEM;
1159
1160 new_node->bytenr = dest->node->start;
1161 new_node->level = node->level;
1162 new_node->lowest = node->lowest;
1163 new_node->checked = 1;
1164 new_node->root = dest;
1165
1166 if (!node->lowest) {
1167 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1168 new_edge = alloc_backref_edge(cache);
1169 if (!new_edge)
1170 goto fail;
1171
1172 new_edge->node[UPPER] = new_node;
1173 new_edge->node[LOWER] = edge->node[LOWER];
1174 list_add_tail(&new_edge->list[UPPER],
1175 &new_node->lower);
1176 }
1177 } else {
1178 list_add_tail(&new_node->lower, &cache->leaves);
1179 }
1180
1181 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1182 &new_node->rb_node);
1183 BUG_ON(rb_node);
1184
1185 if (!new_node->lowest) {
1186 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1187 list_add_tail(&new_edge->list[LOWER],
1188 &new_edge->node[LOWER]->upper);
1189 }
1190 }
1191 return 0;
1192 fail:
1193 while (!list_empty(&new_node->lower)) {
1194 new_edge = list_entry(new_node->lower.next,
1195 struct backref_edge, list[UPPER]);
1196 list_del(&new_edge->list[UPPER]);
1197 free_backref_edge(cache, new_edge);
1198 }
1199 free_backref_node(cache, new_node);
1200 return -ENOMEM;
1201 }
1202
1203 /*
1204 * helper to add 'address of tree root -> reloc tree' mapping
1205 */
1206 static int __add_reloc_root(struct btrfs_root *root)
1207 {
1208 struct rb_node *rb_node;
1209 struct mapping_node *node;
1210 struct reloc_control *rc = root->fs_info->reloc_ctl;
1211
1212 node = kmalloc(sizeof(*node), GFP_NOFS);
1213 BUG_ON(!node);
1214
1215 node->bytenr = root->node->start;
1216 node->data = root;
1217
1218 spin_lock(&rc->reloc_root_tree.lock);
1219 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1220 node->bytenr, &node->rb_node);
1221 spin_unlock(&rc->reloc_root_tree.lock);
1222 BUG_ON(rb_node);
1223
1224 list_add_tail(&root->root_list, &rc->reloc_roots);
1225 return 0;
1226 }
1227
1228 /*
1229 * helper to update/delete the 'address of tree root -> reloc tree'
1230 * mapping
1231 */
1232 static int __update_reloc_root(struct btrfs_root *root, int del)
1233 {
1234 struct rb_node *rb_node;
1235 struct mapping_node *node = NULL;
1236 struct reloc_control *rc = root->fs_info->reloc_ctl;
1237
1238 spin_lock(&rc->reloc_root_tree.lock);
1239 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1240 root->commit_root->start);
1241 if (rb_node) {
1242 node = rb_entry(rb_node, struct mapping_node, rb_node);
1243 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1244 }
1245 spin_unlock(&rc->reloc_root_tree.lock);
1246
1247 BUG_ON((struct btrfs_root *)node->data != root);
1248
1249 if (!del) {
1250 spin_lock(&rc->reloc_root_tree.lock);
1251 node->bytenr = root->node->start;
1252 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1253 node->bytenr, &node->rb_node);
1254 spin_unlock(&rc->reloc_root_tree.lock);
1255 BUG_ON(rb_node);
1256 } else {
1257 list_del_init(&root->root_list);
1258 kfree(node);
1259 }
1260 return 0;
1261 }
1262
1263 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1264 struct btrfs_root *root, u64 objectid)
1265 {
1266 struct btrfs_root *reloc_root;
1267 struct extent_buffer *eb;
1268 struct btrfs_root_item *root_item;
1269 struct btrfs_key root_key;
1270 int ret;
1271
1272 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1273 BUG_ON(!root_item);
1274
1275 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1276 root_key.type = BTRFS_ROOT_ITEM_KEY;
1277 root_key.offset = objectid;
1278
1279 if (root->root_key.objectid == objectid) {
1280 /* called by btrfs_init_reloc_root */
1281 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1282 BTRFS_TREE_RELOC_OBJECTID);
1283 BUG_ON(ret);
1284
1285 btrfs_set_root_last_snapshot(&root->root_item,
1286 trans->transid - 1);
1287 } else {
1288 /*
1289 * called by btrfs_reloc_post_snapshot_hook.
1290 * the source tree is a reloc tree, all tree blocks
1291 * modified after it was created have RELOC flag
1292 * set in their headers. so it's OK to not update
1293 * the 'last_snapshot'.
1294 */
1295 ret = btrfs_copy_root(trans, root, root->node, &eb,
1296 BTRFS_TREE_RELOC_OBJECTID);
1297 BUG_ON(ret);
1298 }
1299
1300 memcpy(root_item, &root->root_item, sizeof(*root_item));
1301 btrfs_set_root_bytenr(root_item, eb->start);
1302 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1303 btrfs_set_root_generation(root_item, trans->transid);
1304
1305 if (root->root_key.objectid == objectid) {
1306 btrfs_set_root_refs(root_item, 0);
1307 memset(&root_item->drop_progress, 0,
1308 sizeof(struct btrfs_disk_key));
1309 root_item->drop_level = 0;
1310 }
1311
1312 btrfs_tree_unlock(eb);
1313 free_extent_buffer(eb);
1314
1315 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1316 &root_key, root_item);
1317 BUG_ON(ret);
1318 kfree(root_item);
1319
1320 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1321 &root_key);
1322 BUG_ON(IS_ERR(reloc_root));
1323 reloc_root->last_trans = trans->transid;
1324 return reloc_root;
1325 }
1326
1327 /*
1328 * create reloc tree for a given fs tree. reloc tree is just a
1329 * snapshot of the fs tree with special root objectid.
1330 */
1331 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1332 struct btrfs_root *root)
1333 {
1334 struct btrfs_root *reloc_root;
1335 struct reloc_control *rc = root->fs_info->reloc_ctl;
1336 int clear_rsv = 0;
1337
1338 if (root->reloc_root) {
1339 reloc_root = root->reloc_root;
1340 reloc_root->last_trans = trans->transid;
1341 return 0;
1342 }
1343
1344 if (!rc || !rc->create_reloc_tree ||
1345 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1346 return 0;
1347
1348 if (!trans->block_rsv) {
1349 trans->block_rsv = rc->block_rsv;
1350 clear_rsv = 1;
1351 }
1352 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1353 if (clear_rsv)
1354 trans->block_rsv = NULL;
1355
1356 __add_reloc_root(reloc_root);
1357 root->reloc_root = reloc_root;
1358 return 0;
1359 }
1360
1361 /*
1362 * update root item of reloc tree
1363 */
1364 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1365 struct btrfs_root *root)
1366 {
1367 struct btrfs_root *reloc_root;
1368 struct btrfs_root_item *root_item;
1369 int del = 0;
1370 int ret;
1371
1372 if (!root->reloc_root)
1373 goto out;
1374
1375 reloc_root = root->reloc_root;
1376 root_item = &reloc_root->root_item;
1377
1378 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1379 btrfs_root_refs(root_item) == 0) {
1380 root->reloc_root = NULL;
1381 del = 1;
1382 }
1383
1384 __update_reloc_root(reloc_root, del);
1385
1386 if (reloc_root->commit_root != reloc_root->node) {
1387 btrfs_set_root_node(root_item, reloc_root->node);
1388 free_extent_buffer(reloc_root->commit_root);
1389 reloc_root->commit_root = btrfs_root_node(reloc_root);
1390 }
1391
1392 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1393 &reloc_root->root_key, root_item);
1394 BUG_ON(ret);
1395
1396 out:
1397 return 0;
1398 }
1399
1400 /*
1401 * helper to find first cached inode with inode number >= objectid
1402 * in a subvolume
1403 */
1404 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1405 {
1406 struct rb_node *node;
1407 struct rb_node *prev;
1408 struct btrfs_inode *entry;
1409 struct inode *inode;
1410
1411 spin_lock(&root->inode_lock);
1412 again:
1413 node = root->inode_tree.rb_node;
1414 prev = NULL;
1415 while (node) {
1416 prev = node;
1417 entry = rb_entry(node, struct btrfs_inode, rb_node);
1418
1419 if (objectid < btrfs_ino(&entry->vfs_inode))
1420 node = node->rb_left;
1421 else if (objectid > btrfs_ino(&entry->vfs_inode))
1422 node = node->rb_right;
1423 else
1424 break;
1425 }
1426 if (!node) {
1427 while (prev) {
1428 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1429 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1430 node = prev;
1431 break;
1432 }
1433 prev = rb_next(prev);
1434 }
1435 }
1436 while (node) {
1437 entry = rb_entry(node, struct btrfs_inode, rb_node);
1438 inode = igrab(&entry->vfs_inode);
1439 if (inode) {
1440 spin_unlock(&root->inode_lock);
1441 return inode;
1442 }
1443
1444 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1445 if (cond_resched_lock(&root->inode_lock))
1446 goto again;
1447
1448 node = rb_next(node);
1449 }
1450 spin_unlock(&root->inode_lock);
1451 return NULL;
1452 }
1453
1454 static int in_block_group(u64 bytenr,
1455 struct btrfs_block_group_cache *block_group)
1456 {
1457 if (bytenr >= block_group->key.objectid &&
1458 bytenr < block_group->key.objectid + block_group->key.offset)
1459 return 1;
1460 return 0;
1461 }
1462
1463 /*
1464 * get new location of data
1465 */
1466 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1467 u64 bytenr, u64 num_bytes)
1468 {
1469 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1470 struct btrfs_path *path;
1471 struct btrfs_file_extent_item *fi;
1472 struct extent_buffer *leaf;
1473 int ret;
1474
1475 path = btrfs_alloc_path();
1476 if (!path)
1477 return -ENOMEM;
1478
1479 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1480 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1481 bytenr, 0);
1482 if (ret < 0)
1483 goto out;
1484 if (ret > 0) {
1485 ret = -ENOENT;
1486 goto out;
1487 }
1488
1489 leaf = path->nodes[0];
1490 fi = btrfs_item_ptr(leaf, path->slots[0],
1491 struct btrfs_file_extent_item);
1492
1493 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1494 btrfs_file_extent_compression(leaf, fi) ||
1495 btrfs_file_extent_encryption(leaf, fi) ||
1496 btrfs_file_extent_other_encoding(leaf, fi));
1497
1498 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1499 ret = 1;
1500 goto out;
1501 }
1502
1503 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1504 ret = 0;
1505 out:
1506 btrfs_free_path(path);
1507 return ret;
1508 }
1509
1510 /*
1511 * update file extent items in the tree leaf to point to
1512 * the new locations.
1513 */
1514 static noinline_for_stack
1515 int replace_file_extents(struct btrfs_trans_handle *trans,
1516 struct reloc_control *rc,
1517 struct btrfs_root *root,
1518 struct extent_buffer *leaf)
1519 {
1520 struct btrfs_key key;
1521 struct btrfs_file_extent_item *fi;
1522 struct inode *inode = NULL;
1523 u64 parent;
1524 u64 bytenr;
1525 u64 new_bytenr = 0;
1526 u64 num_bytes;
1527 u64 end;
1528 u32 nritems;
1529 u32 i;
1530 int ret;
1531 int first = 1;
1532 int dirty = 0;
1533
1534 if (rc->stage != UPDATE_DATA_PTRS)
1535 return 0;
1536
1537 /* reloc trees always use full backref */
1538 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1539 parent = leaf->start;
1540 else
1541 parent = 0;
1542
1543 nritems = btrfs_header_nritems(leaf);
1544 for (i = 0; i < nritems; i++) {
1545 cond_resched();
1546 btrfs_item_key_to_cpu(leaf, &key, i);
1547 if (key.type != BTRFS_EXTENT_DATA_KEY)
1548 continue;
1549 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1550 if (btrfs_file_extent_type(leaf, fi) ==
1551 BTRFS_FILE_EXTENT_INLINE)
1552 continue;
1553 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1554 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1555 if (bytenr == 0)
1556 continue;
1557 if (!in_block_group(bytenr, rc->block_group))
1558 continue;
1559
1560 /*
1561 * if we are modifying block in fs tree, wait for readpage
1562 * to complete and drop the extent cache
1563 */
1564 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1565 if (first) {
1566 inode = find_next_inode(root, key.objectid);
1567 first = 0;
1568 } else if (inode && btrfs_ino(inode) < key.objectid) {
1569 btrfs_add_delayed_iput(inode);
1570 inode = find_next_inode(root, key.objectid);
1571 }
1572 if (inode && btrfs_ino(inode) == key.objectid) {
1573 end = key.offset +
1574 btrfs_file_extent_num_bytes(leaf, fi);
1575 WARN_ON(!IS_ALIGNED(key.offset,
1576 root->sectorsize));
1577 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1578 end--;
1579 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1580 key.offset, end,
1581 GFP_NOFS);
1582 if (!ret)
1583 continue;
1584
1585 btrfs_drop_extent_cache(inode, key.offset, end,
1586 1);
1587 unlock_extent(&BTRFS_I(inode)->io_tree,
1588 key.offset, end, GFP_NOFS);
1589 }
1590 }
1591
1592 ret = get_new_location(rc->data_inode, &new_bytenr,
1593 bytenr, num_bytes);
1594 if (ret > 0) {
1595 WARN_ON(1);
1596 continue;
1597 }
1598 BUG_ON(ret < 0);
1599
1600 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1601 dirty = 1;
1602
1603 key.offset -= btrfs_file_extent_offset(leaf, fi);
1604 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1605 num_bytes, parent,
1606 btrfs_header_owner(leaf),
1607 key.objectid, key.offset, 1);
1608 BUG_ON(ret);
1609
1610 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1611 parent, btrfs_header_owner(leaf),
1612 key.objectid, key.offset, 1);
1613 BUG_ON(ret);
1614 }
1615 if (dirty)
1616 btrfs_mark_buffer_dirty(leaf);
1617 if (inode)
1618 btrfs_add_delayed_iput(inode);
1619 return 0;
1620 }
1621
1622 static noinline_for_stack
1623 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1624 struct btrfs_path *path, int level)
1625 {
1626 struct btrfs_disk_key key1;
1627 struct btrfs_disk_key key2;
1628 btrfs_node_key(eb, &key1, slot);
1629 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1630 return memcmp(&key1, &key2, sizeof(key1));
1631 }
1632
1633 /*
1634 * try to replace tree blocks in fs tree with the new blocks
1635 * in reloc tree. tree blocks haven't been modified since the
1636 * reloc tree was create can be replaced.
1637 *
1638 * if a block was replaced, level of the block + 1 is returned.
1639 * if no block got replaced, 0 is returned. if there are other
1640 * errors, a negative error number is returned.
1641 */
1642 static noinline_for_stack
1643 int replace_path(struct btrfs_trans_handle *trans,
1644 struct btrfs_root *dest, struct btrfs_root *src,
1645 struct btrfs_path *path, struct btrfs_key *next_key,
1646 int lowest_level, int max_level)
1647 {
1648 struct extent_buffer *eb;
1649 struct extent_buffer *parent;
1650 struct btrfs_key key;
1651 u64 old_bytenr;
1652 u64 new_bytenr;
1653 u64 old_ptr_gen;
1654 u64 new_ptr_gen;
1655 u64 last_snapshot;
1656 u32 blocksize;
1657 int cow = 0;
1658 int level;
1659 int ret;
1660 int slot;
1661
1662 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1663 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1664
1665 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1666 again:
1667 slot = path->slots[lowest_level];
1668 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1669
1670 eb = btrfs_lock_root_node(dest);
1671 btrfs_set_lock_blocking(eb);
1672 level = btrfs_header_level(eb);
1673
1674 if (level < lowest_level) {
1675 btrfs_tree_unlock(eb);
1676 free_extent_buffer(eb);
1677 return 0;
1678 }
1679
1680 if (cow) {
1681 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1682 BUG_ON(ret);
1683 }
1684 btrfs_set_lock_blocking(eb);
1685
1686 if (next_key) {
1687 next_key->objectid = (u64)-1;
1688 next_key->type = (u8)-1;
1689 next_key->offset = (u64)-1;
1690 }
1691
1692 parent = eb;
1693 while (1) {
1694 level = btrfs_header_level(parent);
1695 BUG_ON(level < lowest_level);
1696
1697 ret = btrfs_bin_search(parent, &key, level, &slot);
1698 if (ret && slot > 0)
1699 slot--;
1700
1701 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1702 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1703
1704 old_bytenr = btrfs_node_blockptr(parent, slot);
1705 blocksize = btrfs_level_size(dest, level - 1);
1706 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1707
1708 if (level <= max_level) {
1709 eb = path->nodes[level];
1710 new_bytenr = btrfs_node_blockptr(eb,
1711 path->slots[level]);
1712 new_ptr_gen = btrfs_node_ptr_generation(eb,
1713 path->slots[level]);
1714 } else {
1715 new_bytenr = 0;
1716 new_ptr_gen = 0;
1717 }
1718
1719 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1720 WARN_ON(1);
1721 ret = level;
1722 break;
1723 }
1724
1725 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1726 memcmp_node_keys(parent, slot, path, level)) {
1727 if (level <= lowest_level) {
1728 ret = 0;
1729 break;
1730 }
1731
1732 eb = read_tree_block(dest, old_bytenr, blocksize,
1733 old_ptr_gen);
1734 BUG_ON(!eb);
1735 btrfs_tree_lock(eb);
1736 if (cow) {
1737 ret = btrfs_cow_block(trans, dest, eb, parent,
1738 slot, &eb);
1739 BUG_ON(ret);
1740 }
1741 btrfs_set_lock_blocking(eb);
1742
1743 btrfs_tree_unlock(parent);
1744 free_extent_buffer(parent);
1745
1746 parent = eb;
1747 continue;
1748 }
1749
1750 if (!cow) {
1751 btrfs_tree_unlock(parent);
1752 free_extent_buffer(parent);
1753 cow = 1;
1754 goto again;
1755 }
1756
1757 btrfs_node_key_to_cpu(path->nodes[level], &key,
1758 path->slots[level]);
1759 btrfs_release_path(path);
1760
1761 path->lowest_level = level;
1762 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1763 path->lowest_level = 0;
1764 BUG_ON(ret);
1765
1766 /*
1767 * swap blocks in fs tree and reloc tree.
1768 */
1769 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1770 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1771 btrfs_mark_buffer_dirty(parent);
1772
1773 btrfs_set_node_blockptr(path->nodes[level],
1774 path->slots[level], old_bytenr);
1775 btrfs_set_node_ptr_generation(path->nodes[level],
1776 path->slots[level], old_ptr_gen);
1777 btrfs_mark_buffer_dirty(path->nodes[level]);
1778
1779 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1780 path->nodes[level]->start,
1781 src->root_key.objectid, level - 1, 0,
1782 1);
1783 BUG_ON(ret);
1784 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1785 0, dest->root_key.objectid, level - 1,
1786 0, 1);
1787 BUG_ON(ret);
1788
1789 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1790 path->nodes[level]->start,
1791 src->root_key.objectid, level - 1, 0,
1792 1);
1793 BUG_ON(ret);
1794
1795 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1796 0, dest->root_key.objectid, level - 1,
1797 0, 1);
1798 BUG_ON(ret);
1799
1800 btrfs_unlock_up_safe(path, 0);
1801
1802 ret = level;
1803 break;
1804 }
1805 btrfs_tree_unlock(parent);
1806 free_extent_buffer(parent);
1807 return ret;
1808 }
1809
1810 /*
1811 * helper to find next relocated block in reloc tree
1812 */
1813 static noinline_for_stack
1814 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1815 int *level)
1816 {
1817 struct extent_buffer *eb;
1818 int i;
1819 u64 last_snapshot;
1820 u32 nritems;
1821
1822 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1823
1824 for (i = 0; i < *level; i++) {
1825 free_extent_buffer(path->nodes[i]);
1826 path->nodes[i] = NULL;
1827 }
1828
1829 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1830 eb = path->nodes[i];
1831 nritems = btrfs_header_nritems(eb);
1832 while (path->slots[i] + 1 < nritems) {
1833 path->slots[i]++;
1834 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1835 last_snapshot)
1836 continue;
1837
1838 *level = i;
1839 return 0;
1840 }
1841 free_extent_buffer(path->nodes[i]);
1842 path->nodes[i] = NULL;
1843 }
1844 return 1;
1845 }
1846
1847 /*
1848 * walk down reloc tree to find relocated block of lowest level
1849 */
1850 static noinline_for_stack
1851 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1852 int *level)
1853 {
1854 struct extent_buffer *eb = NULL;
1855 int i;
1856 u64 bytenr;
1857 u64 ptr_gen = 0;
1858 u64 last_snapshot;
1859 u32 blocksize;
1860 u32 nritems;
1861
1862 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1863
1864 for (i = *level; i > 0; i--) {
1865 eb = path->nodes[i];
1866 nritems = btrfs_header_nritems(eb);
1867 while (path->slots[i] < nritems) {
1868 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1869 if (ptr_gen > last_snapshot)
1870 break;
1871 path->slots[i]++;
1872 }
1873 if (path->slots[i] >= nritems) {
1874 if (i == *level)
1875 break;
1876 *level = i + 1;
1877 return 0;
1878 }
1879 if (i == 1) {
1880 *level = i;
1881 return 0;
1882 }
1883
1884 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1885 blocksize = btrfs_level_size(root, i - 1);
1886 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1887 BUG_ON(btrfs_header_level(eb) != i - 1);
1888 path->nodes[i - 1] = eb;
1889 path->slots[i - 1] = 0;
1890 }
1891 return 1;
1892 }
1893
1894 /*
1895 * invalidate extent cache for file extents whose key in range of
1896 * [min_key, max_key)
1897 */
1898 static int invalidate_extent_cache(struct btrfs_root *root,
1899 struct btrfs_key *min_key,
1900 struct btrfs_key *max_key)
1901 {
1902 struct inode *inode = NULL;
1903 u64 objectid;
1904 u64 start, end;
1905 u64 ino;
1906
1907 objectid = min_key->objectid;
1908 while (1) {
1909 cond_resched();
1910 iput(inode);
1911
1912 if (objectid > max_key->objectid)
1913 break;
1914
1915 inode = find_next_inode(root, objectid);
1916 if (!inode)
1917 break;
1918 ino = btrfs_ino(inode);
1919
1920 if (ino > max_key->objectid) {
1921 iput(inode);
1922 break;
1923 }
1924
1925 objectid = ino + 1;
1926 if (!S_ISREG(inode->i_mode))
1927 continue;
1928
1929 if (unlikely(min_key->objectid == ino)) {
1930 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1931 continue;
1932 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1933 start = 0;
1934 else {
1935 start = min_key->offset;
1936 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1937 }
1938 } else {
1939 start = 0;
1940 }
1941
1942 if (unlikely(max_key->objectid == ino)) {
1943 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1944 continue;
1945 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1946 end = (u64)-1;
1947 } else {
1948 if (max_key->offset == 0)
1949 continue;
1950 end = max_key->offset;
1951 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1952 end--;
1953 }
1954 } else {
1955 end = (u64)-1;
1956 }
1957
1958 /* the lock_extent waits for readpage to complete */
1959 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1960 btrfs_drop_extent_cache(inode, start, end, 1);
1961 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1962 }
1963 return 0;
1964 }
1965
1966 static int find_next_key(struct btrfs_path *path, int level,
1967 struct btrfs_key *key)
1968
1969 {
1970 while (level < BTRFS_MAX_LEVEL) {
1971 if (!path->nodes[level])
1972 break;
1973 if (path->slots[level] + 1 <
1974 btrfs_header_nritems(path->nodes[level])) {
1975 btrfs_node_key_to_cpu(path->nodes[level], key,
1976 path->slots[level] + 1);
1977 return 0;
1978 }
1979 level++;
1980 }
1981 return 1;
1982 }
1983
1984 /*
1985 * merge the relocated tree blocks in reloc tree with corresponding
1986 * fs tree.
1987 */
1988 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1989 struct btrfs_root *root)
1990 {
1991 LIST_HEAD(inode_list);
1992 struct btrfs_key key;
1993 struct btrfs_key next_key;
1994 struct btrfs_trans_handle *trans;
1995 struct btrfs_root *reloc_root;
1996 struct btrfs_root_item *root_item;
1997 struct btrfs_path *path;
1998 struct extent_buffer *leaf;
1999 unsigned long nr;
2000 int level;
2001 int max_level;
2002 int replaced = 0;
2003 int ret;
2004 int err = 0;
2005 u32 min_reserved;
2006
2007 path = btrfs_alloc_path();
2008 if (!path)
2009 return -ENOMEM;
2010 path->reada = 1;
2011
2012 reloc_root = root->reloc_root;
2013 root_item = &reloc_root->root_item;
2014
2015 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2016 level = btrfs_root_level(root_item);
2017 extent_buffer_get(reloc_root->node);
2018 path->nodes[level] = reloc_root->node;
2019 path->slots[level] = 0;
2020 } else {
2021 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2022
2023 level = root_item->drop_level;
2024 BUG_ON(level == 0);
2025 path->lowest_level = level;
2026 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2027 path->lowest_level = 0;
2028 if (ret < 0) {
2029 btrfs_free_path(path);
2030 return ret;
2031 }
2032
2033 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2034 path->slots[level]);
2035 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2036
2037 btrfs_unlock_up_safe(path, 0);
2038 }
2039
2040 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2041 memset(&next_key, 0, sizeof(next_key));
2042
2043 while (1) {
2044 trans = btrfs_start_transaction(root, 0);
2045 BUG_ON(IS_ERR(trans));
2046 trans->block_rsv = rc->block_rsv;
2047
2048 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved);
2049 if (ret) {
2050 BUG_ON(ret != -EAGAIN);
2051 ret = btrfs_commit_transaction(trans, root);
2052 BUG_ON(ret);
2053 continue;
2054 }
2055
2056 replaced = 0;
2057 max_level = level;
2058
2059 ret = walk_down_reloc_tree(reloc_root, path, &level);
2060 if (ret < 0) {
2061 err = ret;
2062 goto out;
2063 }
2064 if (ret > 0)
2065 break;
2066
2067 if (!find_next_key(path, level, &key) &&
2068 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2069 ret = 0;
2070 } else {
2071 ret = replace_path(trans, root, reloc_root, path,
2072 &next_key, level, max_level);
2073 }
2074 if (ret < 0) {
2075 err = ret;
2076 goto out;
2077 }
2078
2079 if (ret > 0) {
2080 level = ret;
2081 btrfs_node_key_to_cpu(path->nodes[level], &key,
2082 path->slots[level]);
2083 replaced = 1;
2084 }
2085
2086 ret = walk_up_reloc_tree(reloc_root, path, &level);
2087 if (ret > 0)
2088 break;
2089
2090 BUG_ON(level == 0);
2091 /*
2092 * save the merging progress in the drop_progress.
2093 * this is OK since root refs == 1 in this case.
2094 */
2095 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2096 path->slots[level]);
2097 root_item->drop_level = level;
2098
2099 nr = trans->blocks_used;
2100 btrfs_end_transaction_throttle(trans, root);
2101
2102 btrfs_btree_balance_dirty(root, nr);
2103
2104 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2105 invalidate_extent_cache(root, &key, &next_key);
2106 }
2107
2108 /*
2109 * handle the case only one block in the fs tree need to be
2110 * relocated and the block is tree root.
2111 */
2112 leaf = btrfs_lock_root_node(root);
2113 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2114 btrfs_tree_unlock(leaf);
2115 free_extent_buffer(leaf);
2116 if (ret < 0)
2117 err = ret;
2118 out:
2119 btrfs_free_path(path);
2120
2121 if (err == 0) {
2122 memset(&root_item->drop_progress, 0,
2123 sizeof(root_item->drop_progress));
2124 root_item->drop_level = 0;
2125 btrfs_set_root_refs(root_item, 0);
2126 btrfs_update_reloc_root(trans, root);
2127 }
2128
2129 nr = trans->blocks_used;
2130 btrfs_end_transaction_throttle(trans, root);
2131
2132 btrfs_btree_balance_dirty(root, nr);
2133
2134 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2135 invalidate_extent_cache(root, &key, &next_key);
2136
2137 return err;
2138 }
2139
2140 static noinline_for_stack
2141 int prepare_to_merge(struct reloc_control *rc, int err)
2142 {
2143 struct btrfs_root *root = rc->extent_root;
2144 struct btrfs_root *reloc_root;
2145 struct btrfs_trans_handle *trans;
2146 LIST_HEAD(reloc_roots);
2147 u64 num_bytes = 0;
2148 int ret;
2149
2150 mutex_lock(&root->fs_info->reloc_mutex);
2151 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2152 rc->merging_rsv_size += rc->nodes_relocated * 2;
2153 mutex_unlock(&root->fs_info->reloc_mutex);
2154
2155 again:
2156 if (!err) {
2157 num_bytes = rc->merging_rsv_size;
2158 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2159 if (ret)
2160 err = ret;
2161 }
2162
2163 trans = btrfs_join_transaction(rc->extent_root);
2164 if (IS_ERR(trans)) {
2165 if (!err)
2166 btrfs_block_rsv_release(rc->extent_root,
2167 rc->block_rsv, num_bytes);
2168 return PTR_ERR(trans);
2169 }
2170
2171 if (!err) {
2172 if (num_bytes != rc->merging_rsv_size) {
2173 btrfs_end_transaction(trans, rc->extent_root);
2174 btrfs_block_rsv_release(rc->extent_root,
2175 rc->block_rsv, num_bytes);
2176 goto again;
2177 }
2178 }
2179
2180 rc->merge_reloc_tree = 1;
2181
2182 while (!list_empty(&rc->reloc_roots)) {
2183 reloc_root = list_entry(rc->reloc_roots.next,
2184 struct btrfs_root, root_list);
2185 list_del_init(&reloc_root->root_list);
2186
2187 root = read_fs_root(reloc_root->fs_info,
2188 reloc_root->root_key.offset);
2189 BUG_ON(IS_ERR(root));
2190 BUG_ON(root->reloc_root != reloc_root);
2191
2192 /*
2193 * set reference count to 1, so btrfs_recover_relocation
2194 * knows it should resumes merging
2195 */
2196 if (!err)
2197 btrfs_set_root_refs(&reloc_root->root_item, 1);
2198 btrfs_update_reloc_root(trans, root);
2199
2200 list_add(&reloc_root->root_list, &reloc_roots);
2201 }
2202
2203 list_splice(&reloc_roots, &rc->reloc_roots);
2204
2205 if (!err)
2206 btrfs_commit_transaction(trans, rc->extent_root);
2207 else
2208 btrfs_end_transaction(trans, rc->extent_root);
2209 return err;
2210 }
2211
2212 static noinline_for_stack
2213 int merge_reloc_roots(struct reloc_control *rc)
2214 {
2215 struct btrfs_root *root;
2216 struct btrfs_root *reloc_root;
2217 LIST_HEAD(reloc_roots);
2218 int found = 0;
2219 int ret;
2220 again:
2221 root = rc->extent_root;
2222
2223 /*
2224 * this serializes us with btrfs_record_root_in_transaction,
2225 * we have to make sure nobody is in the middle of
2226 * adding their roots to the list while we are
2227 * doing this splice
2228 */
2229 mutex_lock(&root->fs_info->reloc_mutex);
2230 list_splice_init(&rc->reloc_roots, &reloc_roots);
2231 mutex_unlock(&root->fs_info->reloc_mutex);
2232
2233 while (!list_empty(&reloc_roots)) {
2234 found = 1;
2235 reloc_root = list_entry(reloc_roots.next,
2236 struct btrfs_root, root_list);
2237
2238 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2239 root = read_fs_root(reloc_root->fs_info,
2240 reloc_root->root_key.offset);
2241 BUG_ON(IS_ERR(root));
2242 BUG_ON(root->reloc_root != reloc_root);
2243
2244 ret = merge_reloc_root(rc, root);
2245 BUG_ON(ret);
2246 } else {
2247 list_del_init(&reloc_root->root_list);
2248 }
2249 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2250 }
2251
2252 if (found) {
2253 found = 0;
2254 goto again;
2255 }
2256 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2257 return 0;
2258 }
2259
2260 static void free_block_list(struct rb_root *blocks)
2261 {
2262 struct tree_block *block;
2263 struct rb_node *rb_node;
2264 while ((rb_node = rb_first(blocks))) {
2265 block = rb_entry(rb_node, struct tree_block, rb_node);
2266 rb_erase(rb_node, blocks);
2267 kfree(block);
2268 }
2269 }
2270
2271 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2272 struct btrfs_root *reloc_root)
2273 {
2274 struct btrfs_root *root;
2275
2276 if (reloc_root->last_trans == trans->transid)
2277 return 0;
2278
2279 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2280 BUG_ON(IS_ERR(root));
2281 BUG_ON(root->reloc_root != reloc_root);
2282
2283 return btrfs_record_root_in_trans(trans, root);
2284 }
2285
2286 static noinline_for_stack
2287 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2288 struct reloc_control *rc,
2289 struct backref_node *node,
2290 struct backref_edge *edges[], int *nr)
2291 {
2292 struct backref_node *next;
2293 struct btrfs_root *root;
2294 int index = 0;
2295
2296 next = node;
2297 while (1) {
2298 cond_resched();
2299 next = walk_up_backref(next, edges, &index);
2300 root = next->root;
2301 BUG_ON(!root);
2302 BUG_ON(!root->ref_cows);
2303
2304 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2305 record_reloc_root_in_trans(trans, root);
2306 break;
2307 }
2308
2309 btrfs_record_root_in_trans(trans, root);
2310 root = root->reloc_root;
2311
2312 if (next->new_bytenr != root->node->start) {
2313 BUG_ON(next->new_bytenr);
2314 BUG_ON(!list_empty(&next->list));
2315 next->new_bytenr = root->node->start;
2316 next->root = root;
2317 list_add_tail(&next->list,
2318 &rc->backref_cache.changed);
2319 __mark_block_processed(rc, next);
2320 break;
2321 }
2322
2323 WARN_ON(1);
2324 root = NULL;
2325 next = walk_down_backref(edges, &index);
2326 if (!next || next->level <= node->level)
2327 break;
2328 }
2329 if (!root)
2330 return NULL;
2331
2332 *nr = index;
2333 next = node;
2334 /* setup backref node path for btrfs_reloc_cow_block */
2335 while (1) {
2336 rc->backref_cache.path[next->level] = next;
2337 if (--index < 0)
2338 break;
2339 next = edges[index]->node[UPPER];
2340 }
2341 return root;
2342 }
2343
2344 /*
2345 * select a tree root for relocation. return NULL if the block
2346 * is reference counted. we should use do_relocation() in this
2347 * case. return a tree root pointer if the block isn't reference
2348 * counted. return -ENOENT if the block is root of reloc tree.
2349 */
2350 static noinline_for_stack
2351 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2352 struct backref_node *node)
2353 {
2354 struct backref_node *next;
2355 struct btrfs_root *root;
2356 struct btrfs_root *fs_root = NULL;
2357 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2358 int index = 0;
2359
2360 next = node;
2361 while (1) {
2362 cond_resched();
2363 next = walk_up_backref(next, edges, &index);
2364 root = next->root;
2365 BUG_ON(!root);
2366
2367 /* no other choice for non-references counted tree */
2368 if (!root->ref_cows)
2369 return root;
2370
2371 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2372 fs_root = root;
2373
2374 if (next != node)
2375 return NULL;
2376
2377 next = walk_down_backref(edges, &index);
2378 if (!next || next->level <= node->level)
2379 break;
2380 }
2381
2382 if (!fs_root)
2383 return ERR_PTR(-ENOENT);
2384 return fs_root;
2385 }
2386
2387 static noinline_for_stack
2388 u64 calcu_metadata_size(struct reloc_control *rc,
2389 struct backref_node *node, int reserve)
2390 {
2391 struct backref_node *next = node;
2392 struct backref_edge *edge;
2393 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2394 u64 num_bytes = 0;
2395 int index = 0;
2396
2397 BUG_ON(reserve && node->processed);
2398
2399 while (next) {
2400 cond_resched();
2401 while (1) {
2402 if (next->processed && (reserve || next != node))
2403 break;
2404
2405 num_bytes += btrfs_level_size(rc->extent_root,
2406 next->level);
2407
2408 if (list_empty(&next->upper))
2409 break;
2410
2411 edge = list_entry(next->upper.next,
2412 struct backref_edge, list[LOWER]);
2413 edges[index++] = edge;
2414 next = edge->node[UPPER];
2415 }
2416 next = walk_down_backref(edges, &index);
2417 }
2418 return num_bytes;
2419 }
2420
2421 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2422 struct reloc_control *rc,
2423 struct backref_node *node)
2424 {
2425 struct btrfs_root *root = rc->extent_root;
2426 u64 num_bytes;
2427 int ret;
2428
2429 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2430
2431 trans->block_rsv = rc->block_rsv;
2432 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2433 if (ret) {
2434 if (ret == -EAGAIN)
2435 rc->commit_transaction = 1;
2436 return ret;
2437 }
2438
2439 return 0;
2440 }
2441
2442 static void release_metadata_space(struct reloc_control *rc,
2443 struct backref_node *node)
2444 {
2445 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2446 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2447 }
2448
2449 /*
2450 * relocate a block tree, and then update pointers in upper level
2451 * blocks that reference the block to point to the new location.
2452 *
2453 * if called by link_to_upper, the block has already been relocated.
2454 * in that case this function just updates pointers.
2455 */
2456 static int do_relocation(struct btrfs_trans_handle *trans,
2457 struct reloc_control *rc,
2458 struct backref_node *node,
2459 struct btrfs_key *key,
2460 struct btrfs_path *path, int lowest)
2461 {
2462 struct backref_node *upper;
2463 struct backref_edge *edge;
2464 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2465 struct btrfs_root *root;
2466 struct extent_buffer *eb;
2467 u32 blocksize;
2468 u64 bytenr;
2469 u64 generation;
2470 int nr;
2471 int slot;
2472 int ret;
2473 int err = 0;
2474
2475 BUG_ON(lowest && node->eb);
2476
2477 path->lowest_level = node->level + 1;
2478 rc->backref_cache.path[node->level] = node;
2479 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2480 cond_resched();
2481
2482 upper = edge->node[UPPER];
2483 root = select_reloc_root(trans, rc, upper, edges, &nr);
2484 BUG_ON(!root);
2485
2486 if (upper->eb && !upper->locked) {
2487 if (!lowest) {
2488 ret = btrfs_bin_search(upper->eb, key,
2489 upper->level, &slot);
2490 BUG_ON(ret);
2491 bytenr = btrfs_node_blockptr(upper->eb, slot);
2492 if (node->eb->start == bytenr)
2493 goto next;
2494 }
2495 drop_node_buffer(upper);
2496 }
2497
2498 if (!upper->eb) {
2499 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2500 if (ret < 0) {
2501 err = ret;
2502 break;
2503 }
2504 BUG_ON(ret > 0);
2505
2506 if (!upper->eb) {
2507 upper->eb = path->nodes[upper->level];
2508 path->nodes[upper->level] = NULL;
2509 } else {
2510 BUG_ON(upper->eb != path->nodes[upper->level]);
2511 }
2512
2513 upper->locked = 1;
2514 path->locks[upper->level] = 0;
2515
2516 slot = path->slots[upper->level];
2517 btrfs_release_path(path);
2518 } else {
2519 ret = btrfs_bin_search(upper->eb, key, upper->level,
2520 &slot);
2521 BUG_ON(ret);
2522 }
2523
2524 bytenr = btrfs_node_blockptr(upper->eb, slot);
2525 if (lowest) {
2526 BUG_ON(bytenr != node->bytenr);
2527 } else {
2528 if (node->eb->start == bytenr)
2529 goto next;
2530 }
2531
2532 blocksize = btrfs_level_size(root, node->level);
2533 generation = btrfs_node_ptr_generation(upper->eb, slot);
2534 eb = read_tree_block(root, bytenr, blocksize, generation);
2535 if (!eb) {
2536 err = -EIO;
2537 goto next;
2538 }
2539 btrfs_tree_lock(eb);
2540 btrfs_set_lock_blocking(eb);
2541
2542 if (!node->eb) {
2543 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2544 slot, &eb);
2545 btrfs_tree_unlock(eb);
2546 free_extent_buffer(eb);
2547 if (ret < 0) {
2548 err = ret;
2549 goto next;
2550 }
2551 BUG_ON(node->eb != eb);
2552 } else {
2553 btrfs_set_node_blockptr(upper->eb, slot,
2554 node->eb->start);
2555 btrfs_set_node_ptr_generation(upper->eb, slot,
2556 trans->transid);
2557 btrfs_mark_buffer_dirty(upper->eb);
2558
2559 ret = btrfs_inc_extent_ref(trans, root,
2560 node->eb->start, blocksize,
2561 upper->eb->start,
2562 btrfs_header_owner(upper->eb),
2563 node->level, 0, 1);
2564 BUG_ON(ret);
2565
2566 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2567 BUG_ON(ret);
2568 }
2569 next:
2570 if (!upper->pending)
2571 drop_node_buffer(upper);
2572 else
2573 unlock_node_buffer(upper);
2574 if (err)
2575 break;
2576 }
2577
2578 if (!err && node->pending) {
2579 drop_node_buffer(node);
2580 list_move_tail(&node->list, &rc->backref_cache.changed);
2581 node->pending = 0;
2582 }
2583
2584 path->lowest_level = 0;
2585 BUG_ON(err == -ENOSPC);
2586 return err;
2587 }
2588
2589 static int link_to_upper(struct btrfs_trans_handle *trans,
2590 struct reloc_control *rc,
2591 struct backref_node *node,
2592 struct btrfs_path *path)
2593 {
2594 struct btrfs_key key;
2595
2596 btrfs_node_key_to_cpu(node->eb, &key, 0);
2597 return do_relocation(trans, rc, node, &key, path, 0);
2598 }
2599
2600 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2601 struct reloc_control *rc,
2602 struct btrfs_path *path, int err)
2603 {
2604 LIST_HEAD(list);
2605 struct backref_cache *cache = &rc->backref_cache;
2606 struct backref_node *node;
2607 int level;
2608 int ret;
2609
2610 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2611 while (!list_empty(&cache->pending[level])) {
2612 node = list_entry(cache->pending[level].next,
2613 struct backref_node, list);
2614 list_move_tail(&node->list, &list);
2615 BUG_ON(!node->pending);
2616
2617 if (!err) {
2618 ret = link_to_upper(trans, rc, node, path);
2619 if (ret < 0)
2620 err = ret;
2621 }
2622 }
2623 list_splice_init(&list, &cache->pending[level]);
2624 }
2625 return err;
2626 }
2627
2628 static void mark_block_processed(struct reloc_control *rc,
2629 u64 bytenr, u32 blocksize)
2630 {
2631 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2632 EXTENT_DIRTY, GFP_NOFS);
2633 }
2634
2635 static void __mark_block_processed(struct reloc_control *rc,
2636 struct backref_node *node)
2637 {
2638 u32 blocksize;
2639 if (node->level == 0 ||
2640 in_block_group(node->bytenr, rc->block_group)) {
2641 blocksize = btrfs_level_size(rc->extent_root, node->level);
2642 mark_block_processed(rc, node->bytenr, blocksize);
2643 }
2644 node->processed = 1;
2645 }
2646
2647 /*
2648 * mark a block and all blocks directly/indirectly reference the block
2649 * as processed.
2650 */
2651 static void update_processed_blocks(struct reloc_control *rc,
2652 struct backref_node *node)
2653 {
2654 struct backref_node *next = node;
2655 struct backref_edge *edge;
2656 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2657 int index = 0;
2658
2659 while (next) {
2660 cond_resched();
2661 while (1) {
2662 if (next->processed)
2663 break;
2664
2665 __mark_block_processed(rc, next);
2666
2667 if (list_empty(&next->upper))
2668 break;
2669
2670 edge = list_entry(next->upper.next,
2671 struct backref_edge, list[LOWER]);
2672 edges[index++] = edge;
2673 next = edge->node[UPPER];
2674 }
2675 next = walk_down_backref(edges, &index);
2676 }
2677 }
2678
2679 static int tree_block_processed(u64 bytenr, u32 blocksize,
2680 struct reloc_control *rc)
2681 {
2682 if (test_range_bit(&rc->processed_blocks, bytenr,
2683 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2684 return 1;
2685 return 0;
2686 }
2687
2688 static int get_tree_block_key(struct reloc_control *rc,
2689 struct tree_block *block)
2690 {
2691 struct extent_buffer *eb;
2692
2693 BUG_ON(block->key_ready);
2694 eb = read_tree_block(rc->extent_root, block->bytenr,
2695 block->key.objectid, block->key.offset);
2696 BUG_ON(!eb);
2697 WARN_ON(btrfs_header_level(eb) != block->level);
2698 if (block->level == 0)
2699 btrfs_item_key_to_cpu(eb, &block->key, 0);
2700 else
2701 btrfs_node_key_to_cpu(eb, &block->key, 0);
2702 free_extent_buffer(eb);
2703 block->key_ready = 1;
2704 return 0;
2705 }
2706
2707 static int reada_tree_block(struct reloc_control *rc,
2708 struct tree_block *block)
2709 {
2710 BUG_ON(block->key_ready);
2711 readahead_tree_block(rc->extent_root, block->bytenr,
2712 block->key.objectid, block->key.offset);
2713 return 0;
2714 }
2715
2716 /*
2717 * helper function to relocate a tree block
2718 */
2719 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2720 struct reloc_control *rc,
2721 struct backref_node *node,
2722 struct btrfs_key *key,
2723 struct btrfs_path *path)
2724 {
2725 struct btrfs_root *root;
2726 int release = 0;
2727 int ret = 0;
2728
2729 if (!node)
2730 return 0;
2731
2732 BUG_ON(node->processed);
2733 root = select_one_root(trans, node);
2734 if (root == ERR_PTR(-ENOENT)) {
2735 update_processed_blocks(rc, node);
2736 goto out;
2737 }
2738
2739 if (!root || root->ref_cows) {
2740 ret = reserve_metadata_space(trans, rc, node);
2741 if (ret)
2742 goto out;
2743 release = 1;
2744 }
2745
2746 if (root) {
2747 if (root->ref_cows) {
2748 BUG_ON(node->new_bytenr);
2749 BUG_ON(!list_empty(&node->list));
2750 btrfs_record_root_in_trans(trans, root);
2751 root = root->reloc_root;
2752 node->new_bytenr = root->node->start;
2753 node->root = root;
2754 list_add_tail(&node->list, &rc->backref_cache.changed);
2755 } else {
2756 path->lowest_level = node->level;
2757 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2758 btrfs_release_path(path);
2759 if (ret > 0)
2760 ret = 0;
2761 }
2762 if (!ret)
2763 update_processed_blocks(rc, node);
2764 } else {
2765 ret = do_relocation(trans, rc, node, key, path, 1);
2766 }
2767 out:
2768 if (ret || node->level == 0 || node->cowonly) {
2769 if (release)
2770 release_metadata_space(rc, node);
2771 remove_backref_node(&rc->backref_cache, node);
2772 }
2773 return ret;
2774 }
2775
2776 /*
2777 * relocate a list of blocks
2778 */
2779 static noinline_for_stack
2780 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2781 struct reloc_control *rc, struct rb_root *blocks)
2782 {
2783 struct backref_node *node;
2784 struct btrfs_path *path;
2785 struct tree_block *block;
2786 struct rb_node *rb_node;
2787 int ret;
2788 int err = 0;
2789
2790 path = btrfs_alloc_path();
2791 if (!path)
2792 return -ENOMEM;
2793
2794 rb_node = rb_first(blocks);
2795 while (rb_node) {
2796 block = rb_entry(rb_node, struct tree_block, rb_node);
2797 if (!block->key_ready)
2798 reada_tree_block(rc, block);
2799 rb_node = rb_next(rb_node);
2800 }
2801
2802 rb_node = rb_first(blocks);
2803 while (rb_node) {
2804 block = rb_entry(rb_node, struct tree_block, rb_node);
2805 if (!block->key_ready)
2806 get_tree_block_key(rc, block);
2807 rb_node = rb_next(rb_node);
2808 }
2809
2810 rb_node = rb_first(blocks);
2811 while (rb_node) {
2812 block = rb_entry(rb_node, struct tree_block, rb_node);
2813
2814 node = build_backref_tree(rc, &block->key,
2815 block->level, block->bytenr);
2816 if (IS_ERR(node)) {
2817 err = PTR_ERR(node);
2818 goto out;
2819 }
2820
2821 ret = relocate_tree_block(trans, rc, node, &block->key,
2822 path);
2823 if (ret < 0) {
2824 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2825 err = ret;
2826 goto out;
2827 }
2828 rb_node = rb_next(rb_node);
2829 }
2830 out:
2831 free_block_list(blocks);
2832 err = finish_pending_nodes(trans, rc, path, err);
2833
2834 btrfs_free_path(path);
2835 return err;
2836 }
2837
2838 static noinline_for_stack
2839 int prealloc_file_extent_cluster(struct inode *inode,
2840 struct file_extent_cluster *cluster)
2841 {
2842 u64 alloc_hint = 0;
2843 u64 start;
2844 u64 end;
2845 u64 offset = BTRFS_I(inode)->index_cnt;
2846 u64 num_bytes;
2847 int nr = 0;
2848 int ret = 0;
2849
2850 BUG_ON(cluster->start != cluster->boundary[0]);
2851 mutex_lock(&inode->i_mutex);
2852
2853 ret = btrfs_check_data_free_space(inode, cluster->end +
2854 1 - cluster->start);
2855 if (ret)
2856 goto out;
2857
2858 while (nr < cluster->nr) {
2859 start = cluster->boundary[nr] - offset;
2860 if (nr + 1 < cluster->nr)
2861 end = cluster->boundary[nr + 1] - 1 - offset;
2862 else
2863 end = cluster->end - offset;
2864
2865 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2866 num_bytes = end + 1 - start;
2867 ret = btrfs_prealloc_file_range(inode, 0, start,
2868 num_bytes, num_bytes,
2869 end + 1, &alloc_hint);
2870 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2871 if (ret)
2872 break;
2873 nr++;
2874 }
2875 btrfs_free_reserved_data_space(inode, cluster->end +
2876 1 - cluster->start);
2877 out:
2878 mutex_unlock(&inode->i_mutex);
2879 return ret;
2880 }
2881
2882 static noinline_for_stack
2883 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2884 u64 block_start)
2885 {
2886 struct btrfs_root *root = BTRFS_I(inode)->root;
2887 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2888 struct extent_map *em;
2889 int ret = 0;
2890
2891 em = alloc_extent_map();
2892 if (!em)
2893 return -ENOMEM;
2894
2895 em->start = start;
2896 em->len = end + 1 - start;
2897 em->block_len = em->len;
2898 em->block_start = block_start;
2899 em->bdev = root->fs_info->fs_devices->latest_bdev;
2900 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2901
2902 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2903 while (1) {
2904 write_lock(&em_tree->lock);
2905 ret = add_extent_mapping(em_tree, em);
2906 write_unlock(&em_tree->lock);
2907 if (ret != -EEXIST) {
2908 free_extent_map(em);
2909 break;
2910 }
2911 btrfs_drop_extent_cache(inode, start, end, 0);
2912 }
2913 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2914 return ret;
2915 }
2916
2917 static int relocate_file_extent_cluster(struct inode *inode,
2918 struct file_extent_cluster *cluster)
2919 {
2920 u64 page_start;
2921 u64 page_end;
2922 u64 offset = BTRFS_I(inode)->index_cnt;
2923 unsigned long index;
2924 unsigned long last_index;
2925 struct page *page;
2926 struct file_ra_state *ra;
2927 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2928 int nr = 0;
2929 int ret = 0;
2930
2931 if (!cluster->nr)
2932 return 0;
2933
2934 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2935 if (!ra)
2936 return -ENOMEM;
2937
2938 ret = prealloc_file_extent_cluster(inode, cluster);
2939 if (ret)
2940 goto out;
2941
2942 file_ra_state_init(ra, inode->i_mapping);
2943
2944 ret = setup_extent_mapping(inode, cluster->start - offset,
2945 cluster->end - offset, cluster->start);
2946 if (ret)
2947 goto out;
2948
2949 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2950 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2951 while (index <= last_index) {
2952 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2953 if (ret)
2954 goto out;
2955
2956 page = find_lock_page(inode->i_mapping, index);
2957 if (!page) {
2958 page_cache_sync_readahead(inode->i_mapping,
2959 ra, NULL, index,
2960 last_index + 1 - index);
2961 page = find_or_create_page(inode->i_mapping, index,
2962 mask);
2963 if (!page) {
2964 btrfs_delalloc_release_metadata(inode,
2965 PAGE_CACHE_SIZE);
2966 ret = -ENOMEM;
2967 goto out;
2968 }
2969 }
2970
2971 if (PageReadahead(page)) {
2972 page_cache_async_readahead(inode->i_mapping,
2973 ra, NULL, page, index,
2974 last_index + 1 - index);
2975 }
2976
2977 if (!PageUptodate(page)) {
2978 btrfs_readpage(NULL, page);
2979 lock_page(page);
2980 if (!PageUptodate(page)) {
2981 unlock_page(page);
2982 page_cache_release(page);
2983 btrfs_delalloc_release_metadata(inode,
2984 PAGE_CACHE_SIZE);
2985 ret = -EIO;
2986 goto out;
2987 }
2988 }
2989
2990 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2991 page_end = page_start + PAGE_CACHE_SIZE - 1;
2992
2993 lock_extent(&BTRFS_I(inode)->io_tree,
2994 page_start, page_end, GFP_NOFS);
2995
2996 set_page_extent_mapped(page);
2997
2998 if (nr < cluster->nr &&
2999 page_start + offset == cluster->boundary[nr]) {
3000 set_extent_bits(&BTRFS_I(inode)->io_tree,
3001 page_start, page_end,
3002 EXTENT_BOUNDARY, GFP_NOFS);
3003 nr++;
3004 }
3005
3006 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3007 set_page_dirty(page);
3008
3009 unlock_extent(&BTRFS_I(inode)->io_tree,
3010 page_start, page_end, GFP_NOFS);
3011 unlock_page(page);
3012 page_cache_release(page);
3013
3014 index++;
3015 balance_dirty_pages_ratelimited(inode->i_mapping);
3016 btrfs_throttle(BTRFS_I(inode)->root);
3017 }
3018 WARN_ON(nr != cluster->nr);
3019 out:
3020 kfree(ra);
3021 return ret;
3022 }
3023
3024 static noinline_for_stack
3025 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3026 struct file_extent_cluster *cluster)
3027 {
3028 int ret;
3029
3030 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3031 ret = relocate_file_extent_cluster(inode, cluster);
3032 if (ret)
3033 return ret;
3034 cluster->nr = 0;
3035 }
3036
3037 if (!cluster->nr)
3038 cluster->start = extent_key->objectid;
3039 else
3040 BUG_ON(cluster->nr >= MAX_EXTENTS);
3041 cluster->end = extent_key->objectid + extent_key->offset - 1;
3042 cluster->boundary[cluster->nr] = extent_key->objectid;
3043 cluster->nr++;
3044
3045 if (cluster->nr >= MAX_EXTENTS) {
3046 ret = relocate_file_extent_cluster(inode, cluster);
3047 if (ret)
3048 return ret;
3049 cluster->nr = 0;
3050 }
3051 return 0;
3052 }
3053
3054 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3055 static int get_ref_objectid_v0(struct reloc_control *rc,
3056 struct btrfs_path *path,
3057 struct btrfs_key *extent_key,
3058 u64 *ref_objectid, int *path_change)
3059 {
3060 struct btrfs_key key;
3061 struct extent_buffer *leaf;
3062 struct btrfs_extent_ref_v0 *ref0;
3063 int ret;
3064 int slot;
3065
3066 leaf = path->nodes[0];
3067 slot = path->slots[0];
3068 while (1) {
3069 if (slot >= btrfs_header_nritems(leaf)) {
3070 ret = btrfs_next_leaf(rc->extent_root, path);
3071 if (ret < 0)
3072 return ret;
3073 BUG_ON(ret > 0);
3074 leaf = path->nodes[0];
3075 slot = path->slots[0];
3076 if (path_change)
3077 *path_change = 1;
3078 }
3079 btrfs_item_key_to_cpu(leaf, &key, slot);
3080 if (key.objectid != extent_key->objectid)
3081 return -ENOENT;
3082
3083 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3084 slot++;
3085 continue;
3086 }
3087 ref0 = btrfs_item_ptr(leaf, slot,
3088 struct btrfs_extent_ref_v0);
3089 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3090 break;
3091 }
3092 return 0;
3093 }
3094 #endif
3095
3096 /*
3097 * helper to add a tree block to the list.
3098 * the major work is getting the generation and level of the block
3099 */
3100 static int add_tree_block(struct reloc_control *rc,
3101 struct btrfs_key *extent_key,
3102 struct btrfs_path *path,
3103 struct rb_root *blocks)
3104 {
3105 struct extent_buffer *eb;
3106 struct btrfs_extent_item *ei;
3107 struct btrfs_tree_block_info *bi;
3108 struct tree_block *block;
3109 struct rb_node *rb_node;
3110 u32 item_size;
3111 int level = -1;
3112 int generation;
3113
3114 eb = path->nodes[0];
3115 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3116
3117 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3118 ei = btrfs_item_ptr(eb, path->slots[0],
3119 struct btrfs_extent_item);
3120 bi = (struct btrfs_tree_block_info *)(ei + 1);
3121 generation = btrfs_extent_generation(eb, ei);
3122 level = btrfs_tree_block_level(eb, bi);
3123 } else {
3124 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3125 u64 ref_owner;
3126 int ret;
3127
3128 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3129 ret = get_ref_objectid_v0(rc, path, extent_key,
3130 &ref_owner, NULL);
3131 if (ret < 0)
3132 return ret;
3133 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3134 level = (int)ref_owner;
3135 /* FIXME: get real generation */
3136 generation = 0;
3137 #else
3138 BUG();
3139 #endif
3140 }
3141
3142 btrfs_release_path(path);
3143
3144 BUG_ON(level == -1);
3145
3146 block = kmalloc(sizeof(*block), GFP_NOFS);
3147 if (!block)
3148 return -ENOMEM;
3149
3150 block->bytenr = extent_key->objectid;
3151 block->key.objectid = extent_key->offset;
3152 block->key.offset = generation;
3153 block->level = level;
3154 block->key_ready = 0;
3155
3156 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3157 BUG_ON(rb_node);
3158
3159 return 0;
3160 }
3161
3162 /*
3163 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3164 */
3165 static int __add_tree_block(struct reloc_control *rc,
3166 u64 bytenr, u32 blocksize,
3167 struct rb_root *blocks)
3168 {
3169 struct btrfs_path *path;
3170 struct btrfs_key key;
3171 int ret;
3172
3173 if (tree_block_processed(bytenr, blocksize, rc))
3174 return 0;
3175
3176 if (tree_search(blocks, bytenr))
3177 return 0;
3178
3179 path = btrfs_alloc_path();
3180 if (!path)
3181 return -ENOMEM;
3182
3183 key.objectid = bytenr;
3184 key.type = BTRFS_EXTENT_ITEM_KEY;
3185 key.offset = blocksize;
3186
3187 path->search_commit_root = 1;
3188 path->skip_locking = 1;
3189 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3190 if (ret < 0)
3191 goto out;
3192 BUG_ON(ret);
3193
3194 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3195 ret = add_tree_block(rc, &key, path, blocks);
3196 out:
3197 btrfs_free_path(path);
3198 return ret;
3199 }
3200
3201 /*
3202 * helper to check if the block use full backrefs for pointers in it
3203 */
3204 static int block_use_full_backref(struct reloc_control *rc,
3205 struct extent_buffer *eb)
3206 {
3207 u64 flags;
3208 int ret;
3209
3210 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3211 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3212 return 1;
3213
3214 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3215 eb->start, eb->len, NULL, &flags);
3216 BUG_ON(ret);
3217
3218 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3219 ret = 1;
3220 else
3221 ret = 0;
3222 return ret;
3223 }
3224
3225 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3226 struct inode *inode, u64 ino)
3227 {
3228 struct btrfs_key key;
3229 struct btrfs_path *path;
3230 struct btrfs_root *root = fs_info->tree_root;
3231 struct btrfs_trans_handle *trans;
3232 unsigned long nr;
3233 int ret = 0;
3234
3235 if (inode)
3236 goto truncate;
3237
3238 key.objectid = ino;
3239 key.type = BTRFS_INODE_ITEM_KEY;
3240 key.offset = 0;
3241
3242 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3243 if (IS_ERR_OR_NULL(inode) || is_bad_inode(inode)) {
3244 if (inode && !IS_ERR(inode))
3245 iput(inode);
3246 return -ENOENT;
3247 }
3248
3249 truncate:
3250 path = btrfs_alloc_path();
3251 if (!path) {
3252 ret = -ENOMEM;
3253 goto out;
3254 }
3255
3256 trans = btrfs_join_transaction(root);
3257 if (IS_ERR(trans)) {
3258 btrfs_free_path(path);
3259 ret = PTR_ERR(trans);
3260 goto out;
3261 }
3262
3263 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3264
3265 btrfs_free_path(path);
3266 nr = trans->blocks_used;
3267 btrfs_end_transaction(trans, root);
3268 btrfs_btree_balance_dirty(root, nr);
3269 out:
3270 iput(inode);
3271 return ret;
3272 }
3273
3274 /*
3275 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3276 * this function scans fs tree to find blocks reference the data extent
3277 */
3278 static int find_data_references(struct reloc_control *rc,
3279 struct btrfs_key *extent_key,
3280 struct extent_buffer *leaf,
3281 struct btrfs_extent_data_ref *ref,
3282 struct rb_root *blocks)
3283 {
3284 struct btrfs_path *path;
3285 struct tree_block *block;
3286 struct btrfs_root *root;
3287 struct btrfs_file_extent_item *fi;
3288 struct rb_node *rb_node;
3289 struct btrfs_key key;
3290 u64 ref_root;
3291 u64 ref_objectid;
3292 u64 ref_offset;
3293 u32 ref_count;
3294 u32 nritems;
3295 int err = 0;
3296 int added = 0;
3297 int counted;
3298 int ret;
3299
3300 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3301 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3302 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3303 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3304
3305 /*
3306 * This is an extent belonging to the free space cache, lets just delete
3307 * it and redo the search.
3308 */
3309 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3310 ret = delete_block_group_cache(rc->extent_root->fs_info,
3311 NULL, ref_objectid);
3312 if (ret != -ENOENT)
3313 return ret;
3314 ret = 0;
3315 }
3316
3317 path = btrfs_alloc_path();
3318 if (!path)
3319 return -ENOMEM;
3320 path->reada = 1;
3321
3322 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3323 if (IS_ERR(root)) {
3324 err = PTR_ERR(root);
3325 goto out;
3326 }
3327
3328 key.objectid = ref_objectid;
3329 key.type = BTRFS_EXTENT_DATA_KEY;
3330 if (ref_offset > ((u64)-1 << 32))
3331 key.offset = 0;
3332 else
3333 key.offset = ref_offset;
3334
3335 path->search_commit_root = 1;
3336 path->skip_locking = 1;
3337 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3338 if (ret < 0) {
3339 err = ret;
3340 goto out;
3341 }
3342
3343 leaf = path->nodes[0];
3344 nritems = btrfs_header_nritems(leaf);
3345 /*
3346 * the references in tree blocks that use full backrefs
3347 * are not counted in
3348 */
3349 if (block_use_full_backref(rc, leaf))
3350 counted = 0;
3351 else
3352 counted = 1;
3353 rb_node = tree_search(blocks, leaf->start);
3354 if (rb_node) {
3355 if (counted)
3356 added = 1;
3357 else
3358 path->slots[0] = nritems;
3359 }
3360
3361 while (ref_count > 0) {
3362 while (path->slots[0] >= nritems) {
3363 ret = btrfs_next_leaf(root, path);
3364 if (ret < 0) {
3365 err = ret;
3366 goto out;
3367 }
3368 if (ret > 0) {
3369 WARN_ON(1);
3370 goto out;
3371 }
3372
3373 leaf = path->nodes[0];
3374 nritems = btrfs_header_nritems(leaf);
3375 added = 0;
3376
3377 if (block_use_full_backref(rc, leaf))
3378 counted = 0;
3379 else
3380 counted = 1;
3381 rb_node = tree_search(blocks, leaf->start);
3382 if (rb_node) {
3383 if (counted)
3384 added = 1;
3385 else
3386 path->slots[0] = nritems;
3387 }
3388 }
3389
3390 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3391 if (key.objectid != ref_objectid ||
3392 key.type != BTRFS_EXTENT_DATA_KEY) {
3393 WARN_ON(1);
3394 break;
3395 }
3396
3397 fi = btrfs_item_ptr(leaf, path->slots[0],
3398 struct btrfs_file_extent_item);
3399
3400 if (btrfs_file_extent_type(leaf, fi) ==
3401 BTRFS_FILE_EXTENT_INLINE)
3402 goto next;
3403
3404 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3405 extent_key->objectid)
3406 goto next;
3407
3408 key.offset -= btrfs_file_extent_offset(leaf, fi);
3409 if (key.offset != ref_offset)
3410 goto next;
3411
3412 if (counted)
3413 ref_count--;
3414 if (added)
3415 goto next;
3416
3417 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3418 block = kmalloc(sizeof(*block), GFP_NOFS);
3419 if (!block) {
3420 err = -ENOMEM;
3421 break;
3422 }
3423 block->bytenr = leaf->start;
3424 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3425 block->level = 0;
3426 block->key_ready = 1;
3427 rb_node = tree_insert(blocks, block->bytenr,
3428 &block->rb_node);
3429 BUG_ON(rb_node);
3430 }
3431 if (counted)
3432 added = 1;
3433 else
3434 path->slots[0] = nritems;
3435 next:
3436 path->slots[0]++;
3437
3438 }
3439 out:
3440 btrfs_free_path(path);
3441 return err;
3442 }
3443
3444 /*
3445 * hepler to find all tree blocks that reference a given data extent
3446 */
3447 static noinline_for_stack
3448 int add_data_references(struct reloc_control *rc,
3449 struct btrfs_key *extent_key,
3450 struct btrfs_path *path,
3451 struct rb_root *blocks)
3452 {
3453 struct btrfs_key key;
3454 struct extent_buffer *eb;
3455 struct btrfs_extent_data_ref *dref;
3456 struct btrfs_extent_inline_ref *iref;
3457 unsigned long ptr;
3458 unsigned long end;
3459 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3460 int ret;
3461 int err = 0;
3462
3463 eb = path->nodes[0];
3464 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3465 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3466 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3467 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3468 ptr = end;
3469 else
3470 #endif
3471 ptr += sizeof(struct btrfs_extent_item);
3472
3473 while (ptr < end) {
3474 iref = (struct btrfs_extent_inline_ref *)ptr;
3475 key.type = btrfs_extent_inline_ref_type(eb, iref);
3476 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3477 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3478 ret = __add_tree_block(rc, key.offset, blocksize,
3479 blocks);
3480 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3481 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3482 ret = find_data_references(rc, extent_key,
3483 eb, dref, blocks);
3484 } else {
3485 BUG();
3486 }
3487 ptr += btrfs_extent_inline_ref_size(key.type);
3488 }
3489 WARN_ON(ptr > end);
3490
3491 while (1) {
3492 cond_resched();
3493 eb = path->nodes[0];
3494 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3495 ret = btrfs_next_leaf(rc->extent_root, path);
3496 if (ret < 0) {
3497 err = ret;
3498 break;
3499 }
3500 if (ret > 0)
3501 break;
3502 eb = path->nodes[0];
3503 }
3504
3505 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3506 if (key.objectid != extent_key->objectid)
3507 break;
3508
3509 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3510 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3511 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3512 #else
3513 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3514 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3515 #endif
3516 ret = __add_tree_block(rc, key.offset, blocksize,
3517 blocks);
3518 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3519 dref = btrfs_item_ptr(eb, path->slots[0],
3520 struct btrfs_extent_data_ref);
3521 ret = find_data_references(rc, extent_key,
3522 eb, dref, blocks);
3523 } else {
3524 ret = 0;
3525 }
3526 if (ret) {
3527 err = ret;
3528 break;
3529 }
3530 path->slots[0]++;
3531 }
3532 btrfs_release_path(path);
3533 if (err)
3534 free_block_list(blocks);
3535 return err;
3536 }
3537
3538 /*
3539 * hepler to find next unprocessed extent
3540 */
3541 static noinline_for_stack
3542 int find_next_extent(struct btrfs_trans_handle *trans,
3543 struct reloc_control *rc, struct btrfs_path *path,
3544 struct btrfs_key *extent_key)
3545 {
3546 struct btrfs_key key;
3547 struct extent_buffer *leaf;
3548 u64 start, end, last;
3549 int ret;
3550
3551 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3552 while (1) {
3553 cond_resched();
3554 if (rc->search_start >= last) {
3555 ret = 1;
3556 break;
3557 }
3558
3559 key.objectid = rc->search_start;
3560 key.type = BTRFS_EXTENT_ITEM_KEY;
3561 key.offset = 0;
3562
3563 path->search_commit_root = 1;
3564 path->skip_locking = 1;
3565 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3566 0, 0);
3567 if (ret < 0)
3568 break;
3569 next:
3570 leaf = path->nodes[0];
3571 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3572 ret = btrfs_next_leaf(rc->extent_root, path);
3573 if (ret != 0)
3574 break;
3575 leaf = path->nodes[0];
3576 }
3577
3578 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3579 if (key.objectid >= last) {
3580 ret = 1;
3581 break;
3582 }
3583
3584 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3585 key.objectid + key.offset <= rc->search_start) {
3586 path->slots[0]++;
3587 goto next;
3588 }
3589
3590 ret = find_first_extent_bit(&rc->processed_blocks,
3591 key.objectid, &start, &end,
3592 EXTENT_DIRTY);
3593
3594 if (ret == 0 && start <= key.objectid) {
3595 btrfs_release_path(path);
3596 rc->search_start = end + 1;
3597 } else {
3598 rc->search_start = key.objectid + key.offset;
3599 memcpy(extent_key, &key, sizeof(key));
3600 return 0;
3601 }
3602 }
3603 btrfs_release_path(path);
3604 return ret;
3605 }
3606
3607 static void set_reloc_control(struct reloc_control *rc)
3608 {
3609 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3610
3611 mutex_lock(&fs_info->reloc_mutex);
3612 fs_info->reloc_ctl = rc;
3613 mutex_unlock(&fs_info->reloc_mutex);
3614 }
3615
3616 static void unset_reloc_control(struct reloc_control *rc)
3617 {
3618 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3619
3620 mutex_lock(&fs_info->reloc_mutex);
3621 fs_info->reloc_ctl = NULL;
3622 mutex_unlock(&fs_info->reloc_mutex);
3623 }
3624
3625 static int check_extent_flags(u64 flags)
3626 {
3627 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3628 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3629 return 1;
3630 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3631 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3632 return 1;
3633 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3634 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3635 return 1;
3636 return 0;
3637 }
3638
3639 static noinline_for_stack
3640 int prepare_to_relocate(struct reloc_control *rc)
3641 {
3642 struct btrfs_trans_handle *trans;
3643 int ret;
3644
3645 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3646 if (!rc->block_rsv)
3647 return -ENOMEM;
3648
3649 /*
3650 * reserve some space for creating reloc trees.
3651 * btrfs_init_reloc_root will use them when there
3652 * is no reservation in transaction handle.
3653 */
3654 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3655 rc->extent_root->nodesize * 256);
3656 if (ret)
3657 return ret;
3658
3659 memset(&rc->cluster, 0, sizeof(rc->cluster));
3660 rc->search_start = rc->block_group->key.objectid;
3661 rc->extents_found = 0;
3662 rc->nodes_relocated = 0;
3663 rc->merging_rsv_size = 0;
3664
3665 rc->create_reloc_tree = 1;
3666 set_reloc_control(rc);
3667
3668 trans = btrfs_join_transaction(rc->extent_root);
3669 BUG_ON(IS_ERR(trans));
3670 btrfs_commit_transaction(trans, rc->extent_root);
3671 return 0;
3672 }
3673
3674 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3675 {
3676 struct rb_root blocks = RB_ROOT;
3677 struct btrfs_key key;
3678 struct btrfs_trans_handle *trans = NULL;
3679 struct btrfs_path *path;
3680 struct btrfs_extent_item *ei;
3681 unsigned long nr;
3682 u64 flags;
3683 u32 item_size;
3684 int ret;
3685 int err = 0;
3686 int progress = 0;
3687
3688 path = btrfs_alloc_path();
3689 if (!path)
3690 return -ENOMEM;
3691 path->reada = 1;
3692
3693 ret = prepare_to_relocate(rc);
3694 if (ret) {
3695 err = ret;
3696 goto out_free;
3697 }
3698
3699 while (1) {
3700 progress++;
3701 trans = btrfs_start_transaction(rc->extent_root, 0);
3702 BUG_ON(IS_ERR(trans));
3703 restart:
3704 if (update_backref_cache(trans, &rc->backref_cache)) {
3705 btrfs_end_transaction(trans, rc->extent_root);
3706 continue;
3707 }
3708
3709 ret = find_next_extent(trans, rc, path, &key);
3710 if (ret < 0)
3711 err = ret;
3712 if (ret != 0)
3713 break;
3714
3715 rc->extents_found++;
3716
3717 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3718 struct btrfs_extent_item);
3719 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3720 if (item_size >= sizeof(*ei)) {
3721 flags = btrfs_extent_flags(path->nodes[0], ei);
3722 ret = check_extent_flags(flags);
3723 BUG_ON(ret);
3724
3725 } else {
3726 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3727 u64 ref_owner;
3728 int path_change = 0;
3729
3730 BUG_ON(item_size !=
3731 sizeof(struct btrfs_extent_item_v0));
3732 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3733 &path_change);
3734 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3735 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3736 else
3737 flags = BTRFS_EXTENT_FLAG_DATA;
3738
3739 if (path_change) {
3740 btrfs_release_path(path);
3741
3742 path->search_commit_root = 1;
3743 path->skip_locking = 1;
3744 ret = btrfs_search_slot(NULL, rc->extent_root,
3745 &key, path, 0, 0);
3746 if (ret < 0) {
3747 err = ret;
3748 break;
3749 }
3750 BUG_ON(ret > 0);
3751 }
3752 #else
3753 BUG();
3754 #endif
3755 }
3756
3757 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3758 ret = add_tree_block(rc, &key, path, &blocks);
3759 } else if (rc->stage == UPDATE_DATA_PTRS &&
3760 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3761 ret = add_data_references(rc, &key, path, &blocks);
3762 } else {
3763 btrfs_release_path(path);
3764 ret = 0;
3765 }
3766 if (ret < 0) {
3767 err = ret;
3768 break;
3769 }
3770
3771 if (!RB_EMPTY_ROOT(&blocks)) {
3772 ret = relocate_tree_blocks(trans, rc, &blocks);
3773 if (ret < 0) {
3774 if (ret != -EAGAIN) {
3775 err = ret;
3776 break;
3777 }
3778 rc->extents_found--;
3779 rc->search_start = key.objectid;
3780 }
3781 }
3782
3783 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
3784 if (ret < 0) {
3785 if (ret != -EAGAIN) {
3786 err = ret;
3787 WARN_ON(1);
3788 break;
3789 }
3790 rc->commit_transaction = 1;
3791 }
3792
3793 if (rc->commit_transaction) {
3794 rc->commit_transaction = 0;
3795 ret = btrfs_commit_transaction(trans, rc->extent_root);
3796 BUG_ON(ret);
3797 } else {
3798 nr = trans->blocks_used;
3799 btrfs_end_transaction_throttle(trans, rc->extent_root);
3800 btrfs_btree_balance_dirty(rc->extent_root, nr);
3801 }
3802 trans = NULL;
3803
3804 if (rc->stage == MOVE_DATA_EXTENTS &&
3805 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3806 rc->found_file_extent = 1;
3807 ret = relocate_data_extent(rc->data_inode,
3808 &key, &rc->cluster);
3809 if (ret < 0) {
3810 err = ret;
3811 break;
3812 }
3813 }
3814 }
3815 if (trans && progress && err == -ENOSPC) {
3816 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3817 rc->block_group->flags);
3818 if (ret == 0) {
3819 err = 0;
3820 progress = 0;
3821 goto restart;
3822 }
3823 }
3824
3825 btrfs_release_path(path);
3826 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3827 GFP_NOFS);
3828
3829 if (trans) {
3830 nr = trans->blocks_used;
3831 btrfs_end_transaction_throttle(trans, rc->extent_root);
3832 btrfs_btree_balance_dirty(rc->extent_root, nr);
3833 }
3834
3835 if (!err) {
3836 ret = relocate_file_extent_cluster(rc->data_inode,
3837 &rc->cluster);
3838 if (ret < 0)
3839 err = ret;
3840 }
3841
3842 rc->create_reloc_tree = 0;
3843 set_reloc_control(rc);
3844
3845 backref_cache_cleanup(&rc->backref_cache);
3846 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3847
3848 err = prepare_to_merge(rc, err);
3849
3850 merge_reloc_roots(rc);
3851
3852 rc->merge_reloc_tree = 0;
3853 unset_reloc_control(rc);
3854 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3855
3856 /* get rid of pinned extents */
3857 trans = btrfs_join_transaction(rc->extent_root);
3858 if (IS_ERR(trans))
3859 err = PTR_ERR(trans);
3860 else
3861 btrfs_commit_transaction(trans, rc->extent_root);
3862 out_free:
3863 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3864 btrfs_free_path(path);
3865 return err;
3866 }
3867
3868 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3869 struct btrfs_root *root, u64 objectid)
3870 {
3871 struct btrfs_path *path;
3872 struct btrfs_inode_item *item;
3873 struct extent_buffer *leaf;
3874 int ret;
3875
3876 path = btrfs_alloc_path();
3877 if (!path)
3878 return -ENOMEM;
3879
3880 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3881 if (ret)
3882 goto out;
3883
3884 leaf = path->nodes[0];
3885 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3886 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3887 btrfs_set_inode_generation(leaf, item, 1);
3888 btrfs_set_inode_size(leaf, item, 0);
3889 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3890 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3891 BTRFS_INODE_PREALLOC);
3892 btrfs_mark_buffer_dirty(leaf);
3893 btrfs_release_path(path);
3894 out:
3895 btrfs_free_path(path);
3896 return ret;
3897 }
3898
3899 /*
3900 * helper to create inode for data relocation.
3901 * the inode is in data relocation tree and its link count is 0
3902 */
3903 static noinline_for_stack
3904 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3905 struct btrfs_block_group_cache *group)
3906 {
3907 struct inode *inode = NULL;
3908 struct btrfs_trans_handle *trans;
3909 struct btrfs_root *root;
3910 struct btrfs_key key;
3911 unsigned long nr;
3912 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3913 int err = 0;
3914
3915 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3916 if (IS_ERR(root))
3917 return ERR_CAST(root);
3918
3919 trans = btrfs_start_transaction(root, 6);
3920 if (IS_ERR(trans))
3921 return ERR_CAST(trans);
3922
3923 err = btrfs_find_free_objectid(root, &objectid);
3924 if (err)
3925 goto out;
3926
3927 err = __insert_orphan_inode(trans, root, objectid);
3928 BUG_ON(err);
3929
3930 key.objectid = objectid;
3931 key.type = BTRFS_INODE_ITEM_KEY;
3932 key.offset = 0;
3933 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3934 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3935 BTRFS_I(inode)->index_cnt = group->key.objectid;
3936
3937 err = btrfs_orphan_add(trans, inode);
3938 out:
3939 nr = trans->blocks_used;
3940 btrfs_end_transaction(trans, root);
3941 btrfs_btree_balance_dirty(root, nr);
3942 if (err) {
3943 if (inode)
3944 iput(inode);
3945 inode = ERR_PTR(err);
3946 }
3947 return inode;
3948 }
3949
3950 static struct reloc_control *alloc_reloc_control(void)
3951 {
3952 struct reloc_control *rc;
3953
3954 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3955 if (!rc)
3956 return NULL;
3957
3958 INIT_LIST_HEAD(&rc->reloc_roots);
3959 backref_cache_init(&rc->backref_cache);
3960 mapping_tree_init(&rc->reloc_root_tree);
3961 extent_io_tree_init(&rc->processed_blocks, NULL);
3962 return rc;
3963 }
3964
3965 /*
3966 * function to relocate all extents in a block group.
3967 */
3968 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3969 {
3970 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3971 struct reloc_control *rc;
3972 struct inode *inode;
3973 struct btrfs_path *path;
3974 int ret;
3975 int rw = 0;
3976 int err = 0;
3977
3978 rc = alloc_reloc_control();
3979 if (!rc)
3980 return -ENOMEM;
3981
3982 rc->extent_root = extent_root;
3983
3984 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3985 BUG_ON(!rc->block_group);
3986
3987 if (!rc->block_group->ro) {
3988 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3989 if (ret) {
3990 err = ret;
3991 goto out;
3992 }
3993 rw = 1;
3994 }
3995
3996 path = btrfs_alloc_path();
3997 if (!path) {
3998 err = -ENOMEM;
3999 goto out;
4000 }
4001
4002 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4003 path);
4004 btrfs_free_path(path);
4005
4006 if (!IS_ERR(inode))
4007 ret = delete_block_group_cache(fs_info, inode, 0);
4008 else
4009 ret = PTR_ERR(inode);
4010
4011 if (ret && ret != -ENOENT) {
4012 err = ret;
4013 goto out;
4014 }
4015
4016 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4017 if (IS_ERR(rc->data_inode)) {
4018 err = PTR_ERR(rc->data_inode);
4019 rc->data_inode = NULL;
4020 goto out;
4021 }
4022
4023 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4024 (unsigned long long)rc->block_group->key.objectid,
4025 (unsigned long long)rc->block_group->flags);
4026
4027 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4028 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4029
4030 while (1) {
4031 mutex_lock(&fs_info->cleaner_mutex);
4032
4033 btrfs_clean_old_snapshots(fs_info->tree_root);
4034 ret = relocate_block_group(rc);
4035
4036 mutex_unlock(&fs_info->cleaner_mutex);
4037 if (ret < 0) {
4038 err = ret;
4039 goto out;
4040 }
4041
4042 if (rc->extents_found == 0)
4043 break;
4044
4045 printk(KERN_INFO "btrfs: found %llu extents\n",
4046 (unsigned long long)rc->extents_found);
4047
4048 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4049 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4050 invalidate_mapping_pages(rc->data_inode->i_mapping,
4051 0, -1);
4052 rc->stage = UPDATE_DATA_PTRS;
4053 }
4054 }
4055
4056 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4057 rc->block_group->key.objectid,
4058 rc->block_group->key.objectid +
4059 rc->block_group->key.offset - 1);
4060
4061 WARN_ON(rc->block_group->pinned > 0);
4062 WARN_ON(rc->block_group->reserved > 0);
4063 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4064 out:
4065 if (err && rw)
4066 btrfs_set_block_group_rw(extent_root, rc->block_group);
4067 iput(rc->data_inode);
4068 btrfs_put_block_group(rc->block_group);
4069 kfree(rc);
4070 return err;
4071 }
4072
4073 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4074 {
4075 struct btrfs_trans_handle *trans;
4076 int ret;
4077
4078 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4079 BUG_ON(IS_ERR(trans));
4080
4081 memset(&root->root_item.drop_progress, 0,
4082 sizeof(root->root_item.drop_progress));
4083 root->root_item.drop_level = 0;
4084 btrfs_set_root_refs(&root->root_item, 0);
4085 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4086 &root->root_key, &root->root_item);
4087 BUG_ON(ret);
4088
4089 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4090 BUG_ON(ret);
4091 return 0;
4092 }
4093
4094 /*
4095 * recover relocation interrupted by system crash.
4096 *
4097 * this function resumes merging reloc trees with corresponding fs trees.
4098 * this is important for keeping the sharing of tree blocks
4099 */
4100 int btrfs_recover_relocation(struct btrfs_root *root)
4101 {
4102 LIST_HEAD(reloc_roots);
4103 struct btrfs_key key;
4104 struct btrfs_root *fs_root;
4105 struct btrfs_root *reloc_root;
4106 struct btrfs_path *path;
4107 struct extent_buffer *leaf;
4108 struct reloc_control *rc = NULL;
4109 struct btrfs_trans_handle *trans;
4110 int ret;
4111 int err = 0;
4112
4113 path = btrfs_alloc_path();
4114 if (!path)
4115 return -ENOMEM;
4116 path->reada = -1;
4117
4118 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4119 key.type = BTRFS_ROOT_ITEM_KEY;
4120 key.offset = (u64)-1;
4121
4122 while (1) {
4123 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4124 path, 0, 0);
4125 if (ret < 0) {
4126 err = ret;
4127 goto out;
4128 }
4129 if (ret > 0) {
4130 if (path->slots[0] == 0)
4131 break;
4132 path->slots[0]--;
4133 }
4134 leaf = path->nodes[0];
4135 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4136 btrfs_release_path(path);
4137
4138 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4139 key.type != BTRFS_ROOT_ITEM_KEY)
4140 break;
4141
4142 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4143 if (IS_ERR(reloc_root)) {
4144 err = PTR_ERR(reloc_root);
4145 goto out;
4146 }
4147
4148 list_add(&reloc_root->root_list, &reloc_roots);
4149
4150 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4151 fs_root = read_fs_root(root->fs_info,
4152 reloc_root->root_key.offset);
4153 if (IS_ERR(fs_root)) {
4154 ret = PTR_ERR(fs_root);
4155 if (ret != -ENOENT) {
4156 err = ret;
4157 goto out;
4158 }
4159 mark_garbage_root(reloc_root);
4160 }
4161 }
4162
4163 if (key.offset == 0)
4164 break;
4165
4166 key.offset--;
4167 }
4168 btrfs_release_path(path);
4169
4170 if (list_empty(&reloc_roots))
4171 goto out;
4172
4173 rc = alloc_reloc_control();
4174 if (!rc) {
4175 err = -ENOMEM;
4176 goto out;
4177 }
4178
4179 rc->extent_root = root->fs_info->extent_root;
4180
4181 set_reloc_control(rc);
4182
4183 trans = btrfs_join_transaction(rc->extent_root);
4184 if (IS_ERR(trans)) {
4185 unset_reloc_control(rc);
4186 err = PTR_ERR(trans);
4187 goto out_free;
4188 }
4189
4190 rc->merge_reloc_tree = 1;
4191
4192 while (!list_empty(&reloc_roots)) {
4193 reloc_root = list_entry(reloc_roots.next,
4194 struct btrfs_root, root_list);
4195 list_del(&reloc_root->root_list);
4196
4197 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4198 list_add_tail(&reloc_root->root_list,
4199 &rc->reloc_roots);
4200 continue;
4201 }
4202
4203 fs_root = read_fs_root(root->fs_info,
4204 reloc_root->root_key.offset);
4205 BUG_ON(IS_ERR(fs_root));
4206
4207 __add_reloc_root(reloc_root);
4208 fs_root->reloc_root = reloc_root;
4209 }
4210
4211 btrfs_commit_transaction(trans, rc->extent_root);
4212
4213 merge_reloc_roots(rc);
4214
4215 unset_reloc_control(rc);
4216
4217 trans = btrfs_join_transaction(rc->extent_root);
4218 if (IS_ERR(trans))
4219 err = PTR_ERR(trans);
4220 else
4221 btrfs_commit_transaction(trans, rc->extent_root);
4222 out_free:
4223 kfree(rc);
4224 out:
4225 while (!list_empty(&reloc_roots)) {
4226 reloc_root = list_entry(reloc_roots.next,
4227 struct btrfs_root, root_list);
4228 list_del(&reloc_root->root_list);
4229 free_extent_buffer(reloc_root->node);
4230 free_extent_buffer(reloc_root->commit_root);
4231 kfree(reloc_root);
4232 }
4233 btrfs_free_path(path);
4234
4235 if (err == 0) {
4236 /* cleanup orphan inode in data relocation tree */
4237 fs_root = read_fs_root(root->fs_info,
4238 BTRFS_DATA_RELOC_TREE_OBJECTID);
4239 if (IS_ERR(fs_root))
4240 err = PTR_ERR(fs_root);
4241 else
4242 err = btrfs_orphan_cleanup(fs_root);
4243 }
4244 return err;
4245 }
4246
4247 /*
4248 * helper to add ordered checksum for data relocation.
4249 *
4250 * cloning checksum properly handles the nodatasum extents.
4251 * it also saves CPU time to re-calculate the checksum.
4252 */
4253 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4254 {
4255 struct btrfs_ordered_sum *sums;
4256 struct btrfs_sector_sum *sector_sum;
4257 struct btrfs_ordered_extent *ordered;
4258 struct btrfs_root *root = BTRFS_I(inode)->root;
4259 size_t offset;
4260 int ret;
4261 u64 disk_bytenr;
4262 LIST_HEAD(list);
4263
4264 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4265 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4266
4267 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4268 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4269 disk_bytenr + len - 1, &list, 0);
4270
4271 while (!list_empty(&list)) {
4272 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4273 list_del_init(&sums->list);
4274
4275 sector_sum = sums->sums;
4276 sums->bytenr = ordered->start;
4277
4278 offset = 0;
4279 while (offset < sums->len) {
4280 sector_sum->bytenr += ordered->start - disk_bytenr;
4281 sector_sum++;
4282 offset += root->sectorsize;
4283 }
4284
4285 btrfs_add_ordered_sum(inode, ordered, sums);
4286 }
4287 btrfs_put_ordered_extent(ordered);
4288 return ret;
4289 }
4290
4291 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4292 struct btrfs_root *root, struct extent_buffer *buf,
4293 struct extent_buffer *cow)
4294 {
4295 struct reloc_control *rc;
4296 struct backref_node *node;
4297 int first_cow = 0;
4298 int level;
4299 int ret;
4300
4301 rc = root->fs_info->reloc_ctl;
4302 if (!rc)
4303 return;
4304
4305 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4306 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4307
4308 level = btrfs_header_level(buf);
4309 if (btrfs_header_generation(buf) <=
4310 btrfs_root_last_snapshot(&root->root_item))
4311 first_cow = 1;
4312
4313 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4314 rc->create_reloc_tree) {
4315 WARN_ON(!first_cow && level == 0);
4316
4317 node = rc->backref_cache.path[level];
4318 BUG_ON(node->bytenr != buf->start &&
4319 node->new_bytenr != buf->start);
4320
4321 drop_node_buffer(node);
4322 extent_buffer_get(cow);
4323 node->eb = cow;
4324 node->new_bytenr = cow->start;
4325
4326 if (!node->pending) {
4327 list_move_tail(&node->list,
4328 &rc->backref_cache.pending[level]);
4329 node->pending = 1;
4330 }
4331
4332 if (first_cow)
4333 __mark_block_processed(rc, node);
4334
4335 if (first_cow && level > 0)
4336 rc->nodes_relocated += buf->len;
4337 }
4338
4339 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4340 ret = replace_file_extents(trans, rc, root, cow);
4341 BUG_ON(ret);
4342 }
4343 }
4344
4345 /*
4346 * called before creating snapshot. it calculates metadata reservation
4347 * requried for relocating tree blocks in the snapshot
4348 */
4349 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4350 struct btrfs_pending_snapshot *pending,
4351 u64 *bytes_to_reserve)
4352 {
4353 struct btrfs_root *root;
4354 struct reloc_control *rc;
4355
4356 root = pending->root;
4357 if (!root->reloc_root)
4358 return;
4359
4360 rc = root->fs_info->reloc_ctl;
4361 if (!rc->merge_reloc_tree)
4362 return;
4363
4364 root = root->reloc_root;
4365 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4366 /*
4367 * relocation is in the stage of merging trees. the space
4368 * used by merging a reloc tree is twice the size of
4369 * relocated tree nodes in the worst case. half for cowing
4370 * the reloc tree, half for cowing the fs tree. the space
4371 * used by cowing the reloc tree will be freed after the
4372 * tree is dropped. if we create snapshot, cowing the fs
4373 * tree may use more space than it frees. so we need
4374 * reserve extra space.
4375 */
4376 *bytes_to_reserve += rc->nodes_relocated;
4377 }
4378
4379 /*
4380 * called after snapshot is created. migrate block reservation
4381 * and create reloc root for the newly created snapshot
4382 */
4383 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4384 struct btrfs_pending_snapshot *pending)
4385 {
4386 struct btrfs_root *root = pending->root;
4387 struct btrfs_root *reloc_root;
4388 struct btrfs_root *new_root;
4389 struct reloc_control *rc;
4390 int ret;
4391
4392 if (!root->reloc_root)
4393 return;
4394
4395 rc = root->fs_info->reloc_ctl;
4396 rc->merging_rsv_size += rc->nodes_relocated;
4397
4398 if (rc->merge_reloc_tree) {
4399 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4400 rc->block_rsv,
4401 rc->nodes_relocated);
4402 BUG_ON(ret);
4403 }
4404
4405 new_root = pending->snap;
4406 reloc_root = create_reloc_root(trans, root->reloc_root,
4407 new_root->root_key.objectid);
4408
4409 __add_reloc_root(reloc_root);
4410 new_root->reloc_root = reloc_root;
4411
4412 if (rc->create_reloc_tree) {
4413 ret = clone_backref_node(trans, rc, root, reloc_root);
4414 BUG_ON(ret);
4415 }
4416 }