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Btrfs: cache extent state when writing out dirty metadata pages
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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 void backref_tree_panic(struct rb_node *rb_node, int errno,
330 u64 bytenr)
331 {
332
333 struct btrfs_fs_info *fs_info = NULL;
334 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
335 rb_node);
336 if (bnode->root)
337 fs_info = bnode->root->fs_info;
338 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
339 "found at offset %llu\n", (unsigned long long)bytenr);
340 }
341
342 /*
343 * walk up backref nodes until reach node presents tree root
344 */
345 static struct backref_node *walk_up_backref(struct backref_node *node,
346 struct backref_edge *edges[],
347 int *index)
348 {
349 struct backref_edge *edge;
350 int idx = *index;
351
352 while (!list_empty(&node->upper)) {
353 edge = list_entry(node->upper.next,
354 struct backref_edge, list[LOWER]);
355 edges[idx++] = edge;
356 node = edge->node[UPPER];
357 }
358 BUG_ON(node->detached);
359 *index = idx;
360 return node;
361 }
362
363 /*
364 * walk down backref nodes to find start of next reference path
365 */
366 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
367 int *index)
368 {
369 struct backref_edge *edge;
370 struct backref_node *lower;
371 int idx = *index;
372
373 while (idx > 0) {
374 edge = edges[idx - 1];
375 lower = edge->node[LOWER];
376 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
377 idx--;
378 continue;
379 }
380 edge = list_entry(edge->list[LOWER].next,
381 struct backref_edge, list[LOWER]);
382 edges[idx - 1] = edge;
383 *index = idx;
384 return edge->node[UPPER];
385 }
386 *index = 0;
387 return NULL;
388 }
389
390 static void unlock_node_buffer(struct backref_node *node)
391 {
392 if (node->locked) {
393 btrfs_tree_unlock(node->eb);
394 node->locked = 0;
395 }
396 }
397
398 static void drop_node_buffer(struct backref_node *node)
399 {
400 if (node->eb) {
401 unlock_node_buffer(node);
402 free_extent_buffer(node->eb);
403 node->eb = NULL;
404 }
405 }
406
407 static void drop_backref_node(struct backref_cache *tree,
408 struct backref_node *node)
409 {
410 BUG_ON(!list_empty(&node->upper));
411
412 drop_node_buffer(node);
413 list_del(&node->list);
414 list_del(&node->lower);
415 if (!RB_EMPTY_NODE(&node->rb_node))
416 rb_erase(&node->rb_node, &tree->rb_root);
417 free_backref_node(tree, node);
418 }
419
420 /*
421 * remove a backref node from the backref cache
422 */
423 static void remove_backref_node(struct backref_cache *cache,
424 struct backref_node *node)
425 {
426 struct backref_node *upper;
427 struct backref_edge *edge;
428
429 if (!node)
430 return;
431
432 BUG_ON(!node->lowest && !node->detached);
433 while (!list_empty(&node->upper)) {
434 edge = list_entry(node->upper.next, struct backref_edge,
435 list[LOWER]);
436 upper = edge->node[UPPER];
437 list_del(&edge->list[LOWER]);
438 list_del(&edge->list[UPPER]);
439 free_backref_edge(cache, edge);
440
441 if (RB_EMPTY_NODE(&upper->rb_node)) {
442 BUG_ON(!list_empty(&node->upper));
443 drop_backref_node(cache, node);
444 node = upper;
445 node->lowest = 1;
446 continue;
447 }
448 /*
449 * add the node to leaf node list if no other
450 * child block cached.
451 */
452 if (list_empty(&upper->lower)) {
453 list_add_tail(&upper->lower, &cache->leaves);
454 upper->lowest = 1;
455 }
456 }
457
458 drop_backref_node(cache, node);
459 }
460
461 static void update_backref_node(struct backref_cache *cache,
462 struct backref_node *node, u64 bytenr)
463 {
464 struct rb_node *rb_node;
465 rb_erase(&node->rb_node, &cache->rb_root);
466 node->bytenr = bytenr;
467 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
468 if (rb_node)
469 backref_tree_panic(rb_node, -EEXIST, bytenr);
470 }
471
472 /*
473 * update backref cache after a transaction commit
474 */
475 static int update_backref_cache(struct btrfs_trans_handle *trans,
476 struct backref_cache *cache)
477 {
478 struct backref_node *node;
479 int level = 0;
480
481 if (cache->last_trans == 0) {
482 cache->last_trans = trans->transid;
483 return 0;
484 }
485
486 if (cache->last_trans == trans->transid)
487 return 0;
488
489 /*
490 * detached nodes are used to avoid unnecessary backref
491 * lookup. transaction commit changes the extent tree.
492 * so the detached nodes are no longer useful.
493 */
494 while (!list_empty(&cache->detached)) {
495 node = list_entry(cache->detached.next,
496 struct backref_node, list);
497 remove_backref_node(cache, node);
498 }
499
500 while (!list_empty(&cache->changed)) {
501 node = list_entry(cache->changed.next,
502 struct backref_node, list);
503 list_del_init(&node->list);
504 BUG_ON(node->pending);
505 update_backref_node(cache, node, node->new_bytenr);
506 }
507
508 /*
509 * some nodes can be left in the pending list if there were
510 * errors during processing the pending nodes.
511 */
512 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
513 list_for_each_entry(node, &cache->pending[level], list) {
514 BUG_ON(!node->pending);
515 if (node->bytenr == node->new_bytenr)
516 continue;
517 update_backref_node(cache, node, node->new_bytenr);
518 }
519 }
520
521 cache->last_trans = 0;
522 return 1;
523 }
524
525
526 static int should_ignore_root(struct btrfs_root *root)
527 {
528 struct btrfs_root *reloc_root;
529
530 if (!root->ref_cows)
531 return 0;
532
533 reloc_root = root->reloc_root;
534 if (!reloc_root)
535 return 0;
536
537 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
538 root->fs_info->running_transaction->transid - 1)
539 return 0;
540 /*
541 * if there is reloc tree and it was created in previous
542 * transaction backref lookup can find the reloc tree,
543 * so backref node for the fs tree root is useless for
544 * relocation.
545 */
546 return 1;
547 }
548 /*
549 * find reloc tree by address of tree root
550 */
551 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
552 u64 bytenr)
553 {
554 struct rb_node *rb_node;
555 struct mapping_node *node;
556 struct btrfs_root *root = NULL;
557
558 spin_lock(&rc->reloc_root_tree.lock);
559 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
560 if (rb_node) {
561 node = rb_entry(rb_node, struct mapping_node, rb_node);
562 root = (struct btrfs_root *)node->data;
563 }
564 spin_unlock(&rc->reloc_root_tree.lock);
565 return root;
566 }
567
568 static int is_cowonly_root(u64 root_objectid)
569 {
570 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
571 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
572 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
573 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
574 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
575 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
576 return 1;
577 return 0;
578 }
579
580 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
581 u64 root_objectid)
582 {
583 struct btrfs_key key;
584
585 key.objectid = root_objectid;
586 key.type = BTRFS_ROOT_ITEM_KEY;
587 if (is_cowonly_root(root_objectid))
588 key.offset = 0;
589 else
590 key.offset = (u64)-1;
591
592 return btrfs_read_fs_root_no_name(fs_info, &key);
593 }
594
595 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
596 static noinline_for_stack
597 struct btrfs_root *find_tree_root(struct reloc_control *rc,
598 struct extent_buffer *leaf,
599 struct btrfs_extent_ref_v0 *ref0)
600 {
601 struct btrfs_root *root;
602 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
603 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
604
605 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
606
607 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
608 BUG_ON(IS_ERR(root));
609
610 if (root->ref_cows &&
611 generation != btrfs_root_generation(&root->root_item))
612 return NULL;
613
614 return root;
615 }
616 #endif
617
618 static noinline_for_stack
619 int find_inline_backref(struct extent_buffer *leaf, int slot,
620 unsigned long *ptr, unsigned long *end)
621 {
622 struct btrfs_extent_item *ei;
623 struct btrfs_tree_block_info *bi;
624 u32 item_size;
625
626 item_size = btrfs_item_size_nr(leaf, slot);
627 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
628 if (item_size < sizeof(*ei)) {
629 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
630 return 1;
631 }
632 #endif
633 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
634 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
635 BTRFS_EXTENT_FLAG_TREE_BLOCK));
636
637 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
638 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
639 return 1;
640 }
641
642 bi = (struct btrfs_tree_block_info *)(ei + 1);
643 *ptr = (unsigned long)(bi + 1);
644 *end = (unsigned long)ei + item_size;
645 return 0;
646 }
647
648 /*
649 * build backref tree for a given tree block. root of the backref tree
650 * corresponds the tree block, leaves of the backref tree correspond
651 * roots of b-trees that reference the tree block.
652 *
653 * the basic idea of this function is check backrefs of a given block
654 * to find upper level blocks that refernece the block, and then check
655 * bakcrefs of these upper level blocks recursively. the recursion stop
656 * when tree root is reached or backrefs for the block is cached.
657 *
658 * NOTE: if we find backrefs for a block are cached, we know backrefs
659 * for all upper level blocks that directly/indirectly reference the
660 * block are also cached.
661 */
662 static noinline_for_stack
663 struct backref_node *build_backref_tree(struct reloc_control *rc,
664 struct btrfs_key *node_key,
665 int level, u64 bytenr)
666 {
667 struct backref_cache *cache = &rc->backref_cache;
668 struct btrfs_path *path1;
669 struct btrfs_path *path2;
670 struct extent_buffer *eb;
671 struct btrfs_root *root;
672 struct backref_node *cur;
673 struct backref_node *upper;
674 struct backref_node *lower;
675 struct backref_node *node = NULL;
676 struct backref_node *exist = NULL;
677 struct backref_edge *edge;
678 struct rb_node *rb_node;
679 struct btrfs_key key;
680 unsigned long end;
681 unsigned long ptr;
682 LIST_HEAD(list);
683 LIST_HEAD(useless);
684 int cowonly;
685 int ret;
686 int err = 0;
687
688 path1 = btrfs_alloc_path();
689 path2 = btrfs_alloc_path();
690 if (!path1 || !path2) {
691 err = -ENOMEM;
692 goto out;
693 }
694 path1->reada = 1;
695 path2->reada = 2;
696
697 node = alloc_backref_node(cache);
698 if (!node) {
699 err = -ENOMEM;
700 goto out;
701 }
702
703 node->bytenr = bytenr;
704 node->level = level;
705 node->lowest = 1;
706 cur = node;
707 again:
708 end = 0;
709 ptr = 0;
710 key.objectid = cur->bytenr;
711 key.type = BTRFS_EXTENT_ITEM_KEY;
712 key.offset = (u64)-1;
713
714 path1->search_commit_root = 1;
715 path1->skip_locking = 1;
716 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
717 0, 0);
718 if (ret < 0) {
719 err = ret;
720 goto out;
721 }
722 BUG_ON(!ret || !path1->slots[0]);
723
724 path1->slots[0]--;
725
726 WARN_ON(cur->checked);
727 if (!list_empty(&cur->upper)) {
728 /*
729 * the backref was added previously when processing
730 * backref of type BTRFS_TREE_BLOCK_REF_KEY
731 */
732 BUG_ON(!list_is_singular(&cur->upper));
733 edge = list_entry(cur->upper.next, struct backref_edge,
734 list[LOWER]);
735 BUG_ON(!list_empty(&edge->list[UPPER]));
736 exist = edge->node[UPPER];
737 /*
738 * add the upper level block to pending list if we need
739 * check its backrefs
740 */
741 if (!exist->checked)
742 list_add_tail(&edge->list[UPPER], &list);
743 } else {
744 exist = NULL;
745 }
746
747 while (1) {
748 cond_resched();
749 eb = path1->nodes[0];
750
751 if (ptr >= end) {
752 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
753 ret = btrfs_next_leaf(rc->extent_root, path1);
754 if (ret < 0) {
755 err = ret;
756 goto out;
757 }
758 if (ret > 0)
759 break;
760 eb = path1->nodes[0];
761 }
762
763 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
764 if (key.objectid != cur->bytenr) {
765 WARN_ON(exist);
766 break;
767 }
768
769 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
770 ret = find_inline_backref(eb, path1->slots[0],
771 &ptr, &end);
772 if (ret)
773 goto next;
774 }
775 }
776
777 if (ptr < end) {
778 /* update key for inline back ref */
779 struct btrfs_extent_inline_ref *iref;
780 iref = (struct btrfs_extent_inline_ref *)ptr;
781 key.type = btrfs_extent_inline_ref_type(eb, iref);
782 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
783 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
784 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
785 }
786
787 if (exist &&
788 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
789 exist->owner == key.offset) ||
790 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
791 exist->bytenr == key.offset))) {
792 exist = NULL;
793 goto next;
794 }
795
796 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
797 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
798 key.type == BTRFS_EXTENT_REF_V0_KEY) {
799 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
800 struct btrfs_extent_ref_v0 *ref0;
801 ref0 = btrfs_item_ptr(eb, path1->slots[0],
802 struct btrfs_extent_ref_v0);
803 if (key.objectid == key.offset) {
804 root = find_tree_root(rc, eb, ref0);
805 if (root && !should_ignore_root(root))
806 cur->root = root;
807 else
808 list_add(&cur->list, &useless);
809 break;
810 }
811 if (is_cowonly_root(btrfs_ref_root_v0(eb,
812 ref0)))
813 cur->cowonly = 1;
814 }
815 #else
816 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
818 #endif
819 if (key.objectid == key.offset) {
820 /*
821 * only root blocks of reloc trees use
822 * backref of this type.
823 */
824 root = find_reloc_root(rc, cur->bytenr);
825 BUG_ON(!root);
826 cur->root = root;
827 break;
828 }
829
830 edge = alloc_backref_edge(cache);
831 if (!edge) {
832 err = -ENOMEM;
833 goto out;
834 }
835 rb_node = tree_search(&cache->rb_root, key.offset);
836 if (!rb_node) {
837 upper = alloc_backref_node(cache);
838 if (!upper) {
839 free_backref_edge(cache, edge);
840 err = -ENOMEM;
841 goto out;
842 }
843 upper->bytenr = key.offset;
844 upper->level = cur->level + 1;
845 /*
846 * backrefs for the upper level block isn't
847 * cached, add the block to pending list
848 */
849 list_add_tail(&edge->list[UPPER], &list);
850 } else {
851 upper = rb_entry(rb_node, struct backref_node,
852 rb_node);
853 BUG_ON(!upper->checked);
854 INIT_LIST_HEAD(&edge->list[UPPER]);
855 }
856 list_add_tail(&edge->list[LOWER], &cur->upper);
857 edge->node[LOWER] = cur;
858 edge->node[UPPER] = upper;
859
860 goto next;
861 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
862 goto next;
863 }
864
865 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
866 root = read_fs_root(rc->extent_root->fs_info, key.offset);
867 if (IS_ERR(root)) {
868 err = PTR_ERR(root);
869 goto out;
870 }
871
872 if (!root->ref_cows)
873 cur->cowonly = 1;
874
875 if (btrfs_root_level(&root->root_item) == cur->level) {
876 /* tree root */
877 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
878 cur->bytenr);
879 if (should_ignore_root(root))
880 list_add(&cur->list, &useless);
881 else
882 cur->root = root;
883 break;
884 }
885
886 level = cur->level + 1;
887
888 /*
889 * searching the tree to find upper level blocks
890 * reference the block.
891 */
892 path2->search_commit_root = 1;
893 path2->skip_locking = 1;
894 path2->lowest_level = level;
895 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
896 path2->lowest_level = 0;
897 if (ret < 0) {
898 err = ret;
899 goto out;
900 }
901 if (ret > 0 && path2->slots[level] > 0)
902 path2->slots[level]--;
903
904 eb = path2->nodes[level];
905 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
906 cur->bytenr);
907
908 lower = cur;
909 for (; level < BTRFS_MAX_LEVEL; level++) {
910 if (!path2->nodes[level]) {
911 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
912 lower->bytenr);
913 if (should_ignore_root(root))
914 list_add(&lower->list, &useless);
915 else
916 lower->root = root;
917 break;
918 }
919
920 edge = alloc_backref_edge(cache);
921 if (!edge) {
922 err = -ENOMEM;
923 goto out;
924 }
925
926 eb = path2->nodes[level];
927 rb_node = tree_search(&cache->rb_root, eb->start);
928 if (!rb_node) {
929 upper = alloc_backref_node(cache);
930 if (!upper) {
931 free_backref_edge(cache, edge);
932 err = -ENOMEM;
933 goto out;
934 }
935 upper->bytenr = eb->start;
936 upper->owner = btrfs_header_owner(eb);
937 upper->level = lower->level + 1;
938 if (!root->ref_cows)
939 upper->cowonly = 1;
940
941 /*
942 * if we know the block isn't shared
943 * we can void checking its backrefs.
944 */
945 if (btrfs_block_can_be_shared(root, eb))
946 upper->checked = 0;
947 else
948 upper->checked = 1;
949
950 /*
951 * add the block to pending list if we
952 * need check its backrefs. only block
953 * at 'cur->level + 1' is added to the
954 * tail of pending list. this guarantees
955 * we check backrefs from lower level
956 * blocks to upper level blocks.
957 */
958 if (!upper->checked &&
959 level == cur->level + 1) {
960 list_add_tail(&edge->list[UPPER],
961 &list);
962 } else
963 INIT_LIST_HEAD(&edge->list[UPPER]);
964 } else {
965 upper = rb_entry(rb_node, struct backref_node,
966 rb_node);
967 BUG_ON(!upper->checked);
968 INIT_LIST_HEAD(&edge->list[UPPER]);
969 if (!upper->owner)
970 upper->owner = btrfs_header_owner(eb);
971 }
972 list_add_tail(&edge->list[LOWER], &lower->upper);
973 edge->node[LOWER] = lower;
974 edge->node[UPPER] = upper;
975
976 if (rb_node)
977 break;
978 lower = upper;
979 upper = NULL;
980 }
981 btrfs_release_path(path2);
982 next:
983 if (ptr < end) {
984 ptr += btrfs_extent_inline_ref_size(key.type);
985 if (ptr >= end) {
986 WARN_ON(ptr > end);
987 ptr = 0;
988 end = 0;
989 }
990 }
991 if (ptr >= end)
992 path1->slots[0]++;
993 }
994 btrfs_release_path(path1);
995
996 cur->checked = 1;
997 WARN_ON(exist);
998
999 /* the pending list isn't empty, take the first block to process */
1000 if (!list_empty(&list)) {
1001 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1002 list_del_init(&edge->list[UPPER]);
1003 cur = edge->node[UPPER];
1004 goto again;
1005 }
1006
1007 /*
1008 * everything goes well, connect backref nodes and insert backref nodes
1009 * into the cache.
1010 */
1011 BUG_ON(!node->checked);
1012 cowonly = node->cowonly;
1013 if (!cowonly) {
1014 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1015 &node->rb_node);
1016 if (rb_node)
1017 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1018 list_add_tail(&node->lower, &cache->leaves);
1019 }
1020
1021 list_for_each_entry(edge, &node->upper, list[LOWER])
1022 list_add_tail(&edge->list[UPPER], &list);
1023
1024 while (!list_empty(&list)) {
1025 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1026 list_del_init(&edge->list[UPPER]);
1027 upper = edge->node[UPPER];
1028 if (upper->detached) {
1029 list_del(&edge->list[LOWER]);
1030 lower = edge->node[LOWER];
1031 free_backref_edge(cache, edge);
1032 if (list_empty(&lower->upper))
1033 list_add(&lower->list, &useless);
1034 continue;
1035 }
1036
1037 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1038 if (upper->lowest) {
1039 list_del_init(&upper->lower);
1040 upper->lowest = 0;
1041 }
1042
1043 list_add_tail(&edge->list[UPPER], &upper->lower);
1044 continue;
1045 }
1046
1047 BUG_ON(!upper->checked);
1048 BUG_ON(cowonly != upper->cowonly);
1049 if (!cowonly) {
1050 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1051 &upper->rb_node);
1052 if (rb_node)
1053 backref_tree_panic(rb_node, -EEXIST,
1054 upper->bytenr);
1055 }
1056
1057 list_add_tail(&edge->list[UPPER], &upper->lower);
1058
1059 list_for_each_entry(edge, &upper->upper, list[LOWER])
1060 list_add_tail(&edge->list[UPPER], &list);
1061 }
1062 /*
1063 * process useless backref nodes. backref nodes for tree leaves
1064 * are deleted from the cache. backref nodes for upper level
1065 * tree blocks are left in the cache to avoid unnecessary backref
1066 * lookup.
1067 */
1068 while (!list_empty(&useless)) {
1069 upper = list_entry(useless.next, struct backref_node, list);
1070 list_del_init(&upper->list);
1071 BUG_ON(!list_empty(&upper->upper));
1072 if (upper == node)
1073 node = NULL;
1074 if (upper->lowest) {
1075 list_del_init(&upper->lower);
1076 upper->lowest = 0;
1077 }
1078 while (!list_empty(&upper->lower)) {
1079 edge = list_entry(upper->lower.next,
1080 struct backref_edge, list[UPPER]);
1081 list_del(&edge->list[UPPER]);
1082 list_del(&edge->list[LOWER]);
1083 lower = edge->node[LOWER];
1084 free_backref_edge(cache, edge);
1085
1086 if (list_empty(&lower->upper))
1087 list_add(&lower->list, &useless);
1088 }
1089 __mark_block_processed(rc, upper);
1090 if (upper->level > 0) {
1091 list_add(&upper->list, &cache->detached);
1092 upper->detached = 1;
1093 } else {
1094 rb_erase(&upper->rb_node, &cache->rb_root);
1095 free_backref_node(cache, upper);
1096 }
1097 }
1098 out:
1099 btrfs_free_path(path1);
1100 btrfs_free_path(path2);
1101 if (err) {
1102 while (!list_empty(&useless)) {
1103 lower = list_entry(useless.next,
1104 struct backref_node, upper);
1105 list_del_init(&lower->upper);
1106 }
1107 upper = node;
1108 INIT_LIST_HEAD(&list);
1109 while (upper) {
1110 if (RB_EMPTY_NODE(&upper->rb_node)) {
1111 list_splice_tail(&upper->upper, &list);
1112 free_backref_node(cache, upper);
1113 }
1114
1115 if (list_empty(&list))
1116 break;
1117
1118 edge = list_entry(list.next, struct backref_edge,
1119 list[LOWER]);
1120 list_del(&edge->list[LOWER]);
1121 upper = edge->node[UPPER];
1122 free_backref_edge(cache, edge);
1123 }
1124 return ERR_PTR(err);
1125 }
1126 BUG_ON(node && node->detached);
1127 return node;
1128 }
1129
1130 /*
1131 * helper to add backref node for the newly created snapshot.
1132 * the backref node is created by cloning backref node that
1133 * corresponds to root of source tree
1134 */
1135 static int clone_backref_node(struct btrfs_trans_handle *trans,
1136 struct reloc_control *rc,
1137 struct btrfs_root *src,
1138 struct btrfs_root *dest)
1139 {
1140 struct btrfs_root *reloc_root = src->reloc_root;
1141 struct backref_cache *cache = &rc->backref_cache;
1142 struct backref_node *node = NULL;
1143 struct backref_node *new_node;
1144 struct backref_edge *edge;
1145 struct backref_edge *new_edge;
1146 struct rb_node *rb_node;
1147
1148 if (cache->last_trans > 0)
1149 update_backref_cache(trans, cache);
1150
1151 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1152 if (rb_node) {
1153 node = rb_entry(rb_node, struct backref_node, rb_node);
1154 if (node->detached)
1155 node = NULL;
1156 else
1157 BUG_ON(node->new_bytenr != reloc_root->node->start);
1158 }
1159
1160 if (!node) {
1161 rb_node = tree_search(&cache->rb_root,
1162 reloc_root->commit_root->start);
1163 if (rb_node) {
1164 node = rb_entry(rb_node, struct backref_node,
1165 rb_node);
1166 BUG_ON(node->detached);
1167 }
1168 }
1169
1170 if (!node)
1171 return 0;
1172
1173 new_node = alloc_backref_node(cache);
1174 if (!new_node)
1175 return -ENOMEM;
1176
1177 new_node->bytenr = dest->node->start;
1178 new_node->level = node->level;
1179 new_node->lowest = node->lowest;
1180 new_node->checked = 1;
1181 new_node->root = dest;
1182
1183 if (!node->lowest) {
1184 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1185 new_edge = alloc_backref_edge(cache);
1186 if (!new_edge)
1187 goto fail;
1188
1189 new_edge->node[UPPER] = new_node;
1190 new_edge->node[LOWER] = edge->node[LOWER];
1191 list_add_tail(&new_edge->list[UPPER],
1192 &new_node->lower);
1193 }
1194 } else {
1195 list_add_tail(&new_node->lower, &cache->leaves);
1196 }
1197
1198 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1199 &new_node->rb_node);
1200 if (rb_node)
1201 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1202
1203 if (!new_node->lowest) {
1204 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1205 list_add_tail(&new_edge->list[LOWER],
1206 &new_edge->node[LOWER]->upper);
1207 }
1208 }
1209 return 0;
1210 fail:
1211 while (!list_empty(&new_node->lower)) {
1212 new_edge = list_entry(new_node->lower.next,
1213 struct backref_edge, list[UPPER]);
1214 list_del(&new_edge->list[UPPER]);
1215 free_backref_edge(cache, new_edge);
1216 }
1217 free_backref_node(cache, new_node);
1218 return -ENOMEM;
1219 }
1220
1221 /*
1222 * helper to add 'address of tree root -> reloc tree' mapping
1223 */
1224 static int __must_check __add_reloc_root(struct btrfs_root *root)
1225 {
1226 struct rb_node *rb_node;
1227 struct mapping_node *node;
1228 struct reloc_control *rc = root->fs_info->reloc_ctl;
1229
1230 node = kmalloc(sizeof(*node), GFP_NOFS);
1231 if (!node)
1232 return -ENOMEM;
1233
1234 node->bytenr = root->node->start;
1235 node->data = root;
1236
1237 spin_lock(&rc->reloc_root_tree.lock);
1238 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1239 node->bytenr, &node->rb_node);
1240 spin_unlock(&rc->reloc_root_tree.lock);
1241 if (rb_node) {
1242 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1243 "for start=%llu while inserting into relocation "
1244 "tree\n", node->bytenr);
1245 kfree(node);
1246 return -EEXIST;
1247 }
1248
1249 list_add_tail(&root->root_list, &rc->reloc_roots);
1250 return 0;
1251 }
1252
1253 /*
1254 * helper to update/delete the 'address of tree root -> reloc tree'
1255 * mapping
1256 */
1257 static int __update_reloc_root(struct btrfs_root *root, int del)
1258 {
1259 struct rb_node *rb_node;
1260 struct mapping_node *node = NULL;
1261 struct reloc_control *rc = root->fs_info->reloc_ctl;
1262
1263 spin_lock(&rc->reloc_root_tree.lock);
1264 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1265 root->commit_root->start);
1266 if (rb_node) {
1267 node = rb_entry(rb_node, struct mapping_node, rb_node);
1268 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1269 }
1270 spin_unlock(&rc->reloc_root_tree.lock);
1271
1272 BUG_ON((struct btrfs_root *)node->data != root);
1273
1274 if (!del) {
1275 spin_lock(&rc->reloc_root_tree.lock);
1276 node->bytenr = root->node->start;
1277 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1278 node->bytenr, &node->rb_node);
1279 spin_unlock(&rc->reloc_root_tree.lock);
1280 if (rb_node)
1281 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1282 } else {
1283 spin_lock(&root->fs_info->trans_lock);
1284 list_del_init(&root->root_list);
1285 spin_unlock(&root->fs_info->trans_lock);
1286 kfree(node);
1287 }
1288 return 0;
1289 }
1290
1291 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1292 struct btrfs_root *root, u64 objectid)
1293 {
1294 struct btrfs_root *reloc_root;
1295 struct extent_buffer *eb;
1296 struct btrfs_root_item *root_item;
1297 struct btrfs_key root_key;
1298 int ret;
1299
1300 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1301 BUG_ON(!root_item);
1302
1303 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1304 root_key.type = BTRFS_ROOT_ITEM_KEY;
1305 root_key.offset = objectid;
1306
1307 if (root->root_key.objectid == objectid) {
1308 /* called by btrfs_init_reloc_root */
1309 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1310 BTRFS_TREE_RELOC_OBJECTID);
1311 BUG_ON(ret);
1312
1313 btrfs_set_root_last_snapshot(&root->root_item,
1314 trans->transid - 1);
1315 } else {
1316 /*
1317 * called by btrfs_reloc_post_snapshot_hook.
1318 * the source tree is a reloc tree, all tree blocks
1319 * modified after it was created have RELOC flag
1320 * set in their headers. so it's OK to not update
1321 * the 'last_snapshot'.
1322 */
1323 ret = btrfs_copy_root(trans, root, root->node, &eb,
1324 BTRFS_TREE_RELOC_OBJECTID);
1325 BUG_ON(ret);
1326 }
1327
1328 memcpy(root_item, &root->root_item, sizeof(*root_item));
1329 btrfs_set_root_bytenr(root_item, eb->start);
1330 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1331 btrfs_set_root_generation(root_item, trans->transid);
1332
1333 if (root->root_key.objectid == objectid) {
1334 btrfs_set_root_refs(root_item, 0);
1335 memset(&root_item->drop_progress, 0,
1336 sizeof(struct btrfs_disk_key));
1337 root_item->drop_level = 0;
1338 }
1339
1340 btrfs_tree_unlock(eb);
1341 free_extent_buffer(eb);
1342
1343 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1344 &root_key, root_item);
1345 BUG_ON(ret);
1346 kfree(root_item);
1347
1348 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1349 &root_key);
1350 BUG_ON(IS_ERR(reloc_root));
1351 reloc_root->last_trans = trans->transid;
1352 return reloc_root;
1353 }
1354
1355 /*
1356 * create reloc tree for a given fs tree. reloc tree is just a
1357 * snapshot of the fs tree with special root objectid.
1358 */
1359 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1360 struct btrfs_root *root)
1361 {
1362 struct btrfs_root *reloc_root;
1363 struct reloc_control *rc = root->fs_info->reloc_ctl;
1364 int clear_rsv = 0;
1365 int ret;
1366
1367 if (root->reloc_root) {
1368 reloc_root = root->reloc_root;
1369 reloc_root->last_trans = trans->transid;
1370 return 0;
1371 }
1372
1373 if (!rc || !rc->create_reloc_tree ||
1374 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1375 return 0;
1376
1377 if (!trans->block_rsv) {
1378 trans->block_rsv = rc->block_rsv;
1379 clear_rsv = 1;
1380 }
1381 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1382 if (clear_rsv)
1383 trans->block_rsv = NULL;
1384
1385 ret = __add_reloc_root(reloc_root);
1386 BUG_ON(ret < 0);
1387 root->reloc_root = reloc_root;
1388 return 0;
1389 }
1390
1391 /*
1392 * update root item of reloc tree
1393 */
1394 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1395 struct btrfs_root *root)
1396 {
1397 struct btrfs_root *reloc_root;
1398 struct btrfs_root_item *root_item;
1399 int del = 0;
1400 int ret;
1401
1402 if (!root->reloc_root)
1403 goto out;
1404
1405 reloc_root = root->reloc_root;
1406 root_item = &reloc_root->root_item;
1407
1408 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1409 btrfs_root_refs(root_item) == 0) {
1410 root->reloc_root = NULL;
1411 del = 1;
1412 }
1413
1414 __update_reloc_root(reloc_root, del);
1415
1416 if (reloc_root->commit_root != reloc_root->node) {
1417 btrfs_set_root_node(root_item, reloc_root->node);
1418 free_extent_buffer(reloc_root->commit_root);
1419 reloc_root->commit_root = btrfs_root_node(reloc_root);
1420 }
1421
1422 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1423 &reloc_root->root_key, root_item);
1424 BUG_ON(ret);
1425
1426 out:
1427 return 0;
1428 }
1429
1430 /*
1431 * helper to find first cached inode with inode number >= objectid
1432 * in a subvolume
1433 */
1434 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1435 {
1436 struct rb_node *node;
1437 struct rb_node *prev;
1438 struct btrfs_inode *entry;
1439 struct inode *inode;
1440
1441 spin_lock(&root->inode_lock);
1442 again:
1443 node = root->inode_tree.rb_node;
1444 prev = NULL;
1445 while (node) {
1446 prev = node;
1447 entry = rb_entry(node, struct btrfs_inode, rb_node);
1448
1449 if (objectid < btrfs_ino(&entry->vfs_inode))
1450 node = node->rb_left;
1451 else if (objectid > btrfs_ino(&entry->vfs_inode))
1452 node = node->rb_right;
1453 else
1454 break;
1455 }
1456 if (!node) {
1457 while (prev) {
1458 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1459 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1460 node = prev;
1461 break;
1462 }
1463 prev = rb_next(prev);
1464 }
1465 }
1466 while (node) {
1467 entry = rb_entry(node, struct btrfs_inode, rb_node);
1468 inode = igrab(&entry->vfs_inode);
1469 if (inode) {
1470 spin_unlock(&root->inode_lock);
1471 return inode;
1472 }
1473
1474 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1475 if (cond_resched_lock(&root->inode_lock))
1476 goto again;
1477
1478 node = rb_next(node);
1479 }
1480 spin_unlock(&root->inode_lock);
1481 return NULL;
1482 }
1483
1484 static int in_block_group(u64 bytenr,
1485 struct btrfs_block_group_cache *block_group)
1486 {
1487 if (bytenr >= block_group->key.objectid &&
1488 bytenr < block_group->key.objectid + block_group->key.offset)
1489 return 1;
1490 return 0;
1491 }
1492
1493 /*
1494 * get new location of data
1495 */
1496 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1497 u64 bytenr, u64 num_bytes)
1498 {
1499 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1500 struct btrfs_path *path;
1501 struct btrfs_file_extent_item *fi;
1502 struct extent_buffer *leaf;
1503 int ret;
1504
1505 path = btrfs_alloc_path();
1506 if (!path)
1507 return -ENOMEM;
1508
1509 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1510 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1511 bytenr, 0);
1512 if (ret < 0)
1513 goto out;
1514 if (ret > 0) {
1515 ret = -ENOENT;
1516 goto out;
1517 }
1518
1519 leaf = path->nodes[0];
1520 fi = btrfs_item_ptr(leaf, path->slots[0],
1521 struct btrfs_file_extent_item);
1522
1523 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1524 btrfs_file_extent_compression(leaf, fi) ||
1525 btrfs_file_extent_encryption(leaf, fi) ||
1526 btrfs_file_extent_other_encoding(leaf, fi));
1527
1528 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1529 ret = 1;
1530 goto out;
1531 }
1532
1533 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1534 ret = 0;
1535 out:
1536 btrfs_free_path(path);
1537 return ret;
1538 }
1539
1540 /*
1541 * update file extent items in the tree leaf to point to
1542 * the new locations.
1543 */
1544 static noinline_for_stack
1545 int replace_file_extents(struct btrfs_trans_handle *trans,
1546 struct reloc_control *rc,
1547 struct btrfs_root *root,
1548 struct extent_buffer *leaf)
1549 {
1550 struct btrfs_key key;
1551 struct btrfs_file_extent_item *fi;
1552 struct inode *inode = NULL;
1553 u64 parent;
1554 u64 bytenr;
1555 u64 new_bytenr = 0;
1556 u64 num_bytes;
1557 u64 end;
1558 u32 nritems;
1559 u32 i;
1560 int ret;
1561 int first = 1;
1562 int dirty = 0;
1563
1564 if (rc->stage != UPDATE_DATA_PTRS)
1565 return 0;
1566
1567 /* reloc trees always use full backref */
1568 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1569 parent = leaf->start;
1570 else
1571 parent = 0;
1572
1573 nritems = btrfs_header_nritems(leaf);
1574 for (i = 0; i < nritems; i++) {
1575 cond_resched();
1576 btrfs_item_key_to_cpu(leaf, &key, i);
1577 if (key.type != BTRFS_EXTENT_DATA_KEY)
1578 continue;
1579 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1580 if (btrfs_file_extent_type(leaf, fi) ==
1581 BTRFS_FILE_EXTENT_INLINE)
1582 continue;
1583 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1584 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1585 if (bytenr == 0)
1586 continue;
1587 if (!in_block_group(bytenr, rc->block_group))
1588 continue;
1589
1590 /*
1591 * if we are modifying block in fs tree, wait for readpage
1592 * to complete and drop the extent cache
1593 */
1594 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1595 if (first) {
1596 inode = find_next_inode(root, key.objectid);
1597 first = 0;
1598 } else if (inode && btrfs_ino(inode) < key.objectid) {
1599 btrfs_add_delayed_iput(inode);
1600 inode = find_next_inode(root, key.objectid);
1601 }
1602 if (inode && btrfs_ino(inode) == key.objectid) {
1603 end = key.offset +
1604 btrfs_file_extent_num_bytes(leaf, fi);
1605 WARN_ON(!IS_ALIGNED(key.offset,
1606 root->sectorsize));
1607 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1608 end--;
1609 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1610 key.offset, end);
1611 if (!ret)
1612 continue;
1613
1614 btrfs_drop_extent_cache(inode, key.offset, end,
1615 1);
1616 unlock_extent(&BTRFS_I(inode)->io_tree,
1617 key.offset, end);
1618 }
1619 }
1620
1621 ret = get_new_location(rc->data_inode, &new_bytenr,
1622 bytenr, num_bytes);
1623 if (ret > 0) {
1624 WARN_ON(1);
1625 continue;
1626 }
1627 BUG_ON(ret < 0);
1628
1629 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1630 dirty = 1;
1631
1632 key.offset -= btrfs_file_extent_offset(leaf, fi);
1633 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1634 num_bytes, parent,
1635 btrfs_header_owner(leaf),
1636 key.objectid, key.offset, 1);
1637 BUG_ON(ret);
1638
1639 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1640 parent, btrfs_header_owner(leaf),
1641 key.objectid, key.offset, 1);
1642 BUG_ON(ret);
1643 }
1644 if (dirty)
1645 btrfs_mark_buffer_dirty(leaf);
1646 if (inode)
1647 btrfs_add_delayed_iput(inode);
1648 return 0;
1649 }
1650
1651 static noinline_for_stack
1652 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1653 struct btrfs_path *path, int level)
1654 {
1655 struct btrfs_disk_key key1;
1656 struct btrfs_disk_key key2;
1657 btrfs_node_key(eb, &key1, slot);
1658 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1659 return memcmp(&key1, &key2, sizeof(key1));
1660 }
1661
1662 /*
1663 * try to replace tree blocks in fs tree with the new blocks
1664 * in reloc tree. tree blocks haven't been modified since the
1665 * reloc tree was create can be replaced.
1666 *
1667 * if a block was replaced, level of the block + 1 is returned.
1668 * if no block got replaced, 0 is returned. if there are other
1669 * errors, a negative error number is returned.
1670 */
1671 static noinline_for_stack
1672 int replace_path(struct btrfs_trans_handle *trans,
1673 struct btrfs_root *dest, struct btrfs_root *src,
1674 struct btrfs_path *path, struct btrfs_key *next_key,
1675 int lowest_level, int max_level)
1676 {
1677 struct extent_buffer *eb;
1678 struct extent_buffer *parent;
1679 struct btrfs_key key;
1680 u64 old_bytenr;
1681 u64 new_bytenr;
1682 u64 old_ptr_gen;
1683 u64 new_ptr_gen;
1684 u64 last_snapshot;
1685 u32 blocksize;
1686 int cow = 0;
1687 int level;
1688 int ret;
1689 int slot;
1690
1691 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1692 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1693
1694 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1695 again:
1696 slot = path->slots[lowest_level];
1697 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1698
1699 eb = btrfs_lock_root_node(dest);
1700 btrfs_set_lock_blocking(eb);
1701 level = btrfs_header_level(eb);
1702
1703 if (level < lowest_level) {
1704 btrfs_tree_unlock(eb);
1705 free_extent_buffer(eb);
1706 return 0;
1707 }
1708
1709 if (cow) {
1710 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1711 BUG_ON(ret);
1712 }
1713 btrfs_set_lock_blocking(eb);
1714
1715 if (next_key) {
1716 next_key->objectid = (u64)-1;
1717 next_key->type = (u8)-1;
1718 next_key->offset = (u64)-1;
1719 }
1720
1721 parent = eb;
1722 while (1) {
1723 level = btrfs_header_level(parent);
1724 BUG_ON(level < lowest_level);
1725
1726 ret = btrfs_bin_search(parent, &key, level, &slot);
1727 if (ret && slot > 0)
1728 slot--;
1729
1730 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1731 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1732
1733 old_bytenr = btrfs_node_blockptr(parent, slot);
1734 blocksize = btrfs_level_size(dest, level - 1);
1735 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1736
1737 if (level <= max_level) {
1738 eb = path->nodes[level];
1739 new_bytenr = btrfs_node_blockptr(eb,
1740 path->slots[level]);
1741 new_ptr_gen = btrfs_node_ptr_generation(eb,
1742 path->slots[level]);
1743 } else {
1744 new_bytenr = 0;
1745 new_ptr_gen = 0;
1746 }
1747
1748 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1749 WARN_ON(1);
1750 ret = level;
1751 break;
1752 }
1753
1754 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1755 memcmp_node_keys(parent, slot, path, level)) {
1756 if (level <= lowest_level) {
1757 ret = 0;
1758 break;
1759 }
1760
1761 eb = read_tree_block(dest, old_bytenr, blocksize,
1762 old_ptr_gen);
1763 BUG_ON(!eb);
1764 btrfs_tree_lock(eb);
1765 if (cow) {
1766 ret = btrfs_cow_block(trans, dest, eb, parent,
1767 slot, &eb);
1768 BUG_ON(ret);
1769 }
1770 btrfs_set_lock_blocking(eb);
1771
1772 btrfs_tree_unlock(parent);
1773 free_extent_buffer(parent);
1774
1775 parent = eb;
1776 continue;
1777 }
1778
1779 if (!cow) {
1780 btrfs_tree_unlock(parent);
1781 free_extent_buffer(parent);
1782 cow = 1;
1783 goto again;
1784 }
1785
1786 btrfs_node_key_to_cpu(path->nodes[level], &key,
1787 path->slots[level]);
1788 btrfs_release_path(path);
1789
1790 path->lowest_level = level;
1791 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1792 path->lowest_level = 0;
1793 BUG_ON(ret);
1794
1795 /*
1796 * swap blocks in fs tree and reloc tree.
1797 */
1798 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1799 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1800 btrfs_mark_buffer_dirty(parent);
1801
1802 btrfs_set_node_blockptr(path->nodes[level],
1803 path->slots[level], old_bytenr);
1804 btrfs_set_node_ptr_generation(path->nodes[level],
1805 path->slots[level], old_ptr_gen);
1806 btrfs_mark_buffer_dirty(path->nodes[level]);
1807
1808 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1809 path->nodes[level]->start,
1810 src->root_key.objectid, level - 1, 0,
1811 1);
1812 BUG_ON(ret);
1813 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1814 0, dest->root_key.objectid, level - 1,
1815 0, 1);
1816 BUG_ON(ret);
1817
1818 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1819 path->nodes[level]->start,
1820 src->root_key.objectid, level - 1, 0,
1821 1);
1822 BUG_ON(ret);
1823
1824 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1825 0, dest->root_key.objectid, level - 1,
1826 0, 1);
1827 BUG_ON(ret);
1828
1829 btrfs_unlock_up_safe(path, 0);
1830
1831 ret = level;
1832 break;
1833 }
1834 btrfs_tree_unlock(parent);
1835 free_extent_buffer(parent);
1836 return ret;
1837 }
1838
1839 /*
1840 * helper to find next relocated block in reloc tree
1841 */
1842 static noinline_for_stack
1843 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1844 int *level)
1845 {
1846 struct extent_buffer *eb;
1847 int i;
1848 u64 last_snapshot;
1849 u32 nritems;
1850
1851 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1852
1853 for (i = 0; i < *level; i++) {
1854 free_extent_buffer(path->nodes[i]);
1855 path->nodes[i] = NULL;
1856 }
1857
1858 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1859 eb = path->nodes[i];
1860 nritems = btrfs_header_nritems(eb);
1861 while (path->slots[i] + 1 < nritems) {
1862 path->slots[i]++;
1863 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1864 last_snapshot)
1865 continue;
1866
1867 *level = i;
1868 return 0;
1869 }
1870 free_extent_buffer(path->nodes[i]);
1871 path->nodes[i] = NULL;
1872 }
1873 return 1;
1874 }
1875
1876 /*
1877 * walk down reloc tree to find relocated block of lowest level
1878 */
1879 static noinline_for_stack
1880 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1881 int *level)
1882 {
1883 struct extent_buffer *eb = NULL;
1884 int i;
1885 u64 bytenr;
1886 u64 ptr_gen = 0;
1887 u64 last_snapshot;
1888 u32 blocksize;
1889 u32 nritems;
1890
1891 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1892
1893 for (i = *level; i > 0; i--) {
1894 eb = path->nodes[i];
1895 nritems = btrfs_header_nritems(eb);
1896 while (path->slots[i] < nritems) {
1897 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1898 if (ptr_gen > last_snapshot)
1899 break;
1900 path->slots[i]++;
1901 }
1902 if (path->slots[i] >= nritems) {
1903 if (i == *level)
1904 break;
1905 *level = i + 1;
1906 return 0;
1907 }
1908 if (i == 1) {
1909 *level = i;
1910 return 0;
1911 }
1912
1913 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1914 blocksize = btrfs_level_size(root, i - 1);
1915 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1916 BUG_ON(btrfs_header_level(eb) != i - 1);
1917 path->nodes[i - 1] = eb;
1918 path->slots[i - 1] = 0;
1919 }
1920 return 1;
1921 }
1922
1923 /*
1924 * invalidate extent cache for file extents whose key in range of
1925 * [min_key, max_key)
1926 */
1927 static int invalidate_extent_cache(struct btrfs_root *root,
1928 struct btrfs_key *min_key,
1929 struct btrfs_key *max_key)
1930 {
1931 struct inode *inode = NULL;
1932 u64 objectid;
1933 u64 start, end;
1934 u64 ino;
1935
1936 objectid = min_key->objectid;
1937 while (1) {
1938 cond_resched();
1939 iput(inode);
1940
1941 if (objectid > max_key->objectid)
1942 break;
1943
1944 inode = find_next_inode(root, objectid);
1945 if (!inode)
1946 break;
1947 ino = btrfs_ino(inode);
1948
1949 if (ino > max_key->objectid) {
1950 iput(inode);
1951 break;
1952 }
1953
1954 objectid = ino + 1;
1955 if (!S_ISREG(inode->i_mode))
1956 continue;
1957
1958 if (unlikely(min_key->objectid == ino)) {
1959 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1960 continue;
1961 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1962 start = 0;
1963 else {
1964 start = min_key->offset;
1965 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1966 }
1967 } else {
1968 start = 0;
1969 }
1970
1971 if (unlikely(max_key->objectid == ino)) {
1972 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1973 continue;
1974 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1975 end = (u64)-1;
1976 } else {
1977 if (max_key->offset == 0)
1978 continue;
1979 end = max_key->offset;
1980 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1981 end--;
1982 }
1983 } else {
1984 end = (u64)-1;
1985 }
1986
1987 /* the lock_extent waits for readpage to complete */
1988 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
1989 btrfs_drop_extent_cache(inode, start, end, 1);
1990 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
1991 }
1992 return 0;
1993 }
1994
1995 static int find_next_key(struct btrfs_path *path, int level,
1996 struct btrfs_key *key)
1997
1998 {
1999 while (level < BTRFS_MAX_LEVEL) {
2000 if (!path->nodes[level])
2001 break;
2002 if (path->slots[level] + 1 <
2003 btrfs_header_nritems(path->nodes[level])) {
2004 btrfs_node_key_to_cpu(path->nodes[level], key,
2005 path->slots[level] + 1);
2006 return 0;
2007 }
2008 level++;
2009 }
2010 return 1;
2011 }
2012
2013 /*
2014 * merge the relocated tree blocks in reloc tree with corresponding
2015 * fs tree.
2016 */
2017 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2018 struct btrfs_root *root)
2019 {
2020 LIST_HEAD(inode_list);
2021 struct btrfs_key key;
2022 struct btrfs_key next_key;
2023 struct btrfs_trans_handle *trans;
2024 struct btrfs_root *reloc_root;
2025 struct btrfs_root_item *root_item;
2026 struct btrfs_path *path;
2027 struct extent_buffer *leaf;
2028 unsigned long nr;
2029 int level;
2030 int max_level;
2031 int replaced = 0;
2032 int ret;
2033 int err = 0;
2034 u32 min_reserved;
2035
2036 path = btrfs_alloc_path();
2037 if (!path)
2038 return -ENOMEM;
2039 path->reada = 1;
2040
2041 reloc_root = root->reloc_root;
2042 root_item = &reloc_root->root_item;
2043
2044 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2045 level = btrfs_root_level(root_item);
2046 extent_buffer_get(reloc_root->node);
2047 path->nodes[level] = reloc_root->node;
2048 path->slots[level] = 0;
2049 } else {
2050 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2051
2052 level = root_item->drop_level;
2053 BUG_ON(level == 0);
2054 path->lowest_level = level;
2055 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2056 path->lowest_level = 0;
2057 if (ret < 0) {
2058 btrfs_free_path(path);
2059 return ret;
2060 }
2061
2062 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2063 path->slots[level]);
2064 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2065
2066 btrfs_unlock_up_safe(path, 0);
2067 }
2068
2069 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2070 memset(&next_key, 0, sizeof(next_key));
2071
2072 while (1) {
2073 trans = btrfs_start_transaction(root, 0);
2074 BUG_ON(IS_ERR(trans));
2075 trans->block_rsv = rc->block_rsv;
2076
2077 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved);
2078 if (ret) {
2079 BUG_ON(ret != -EAGAIN);
2080 ret = btrfs_commit_transaction(trans, root);
2081 BUG_ON(ret);
2082 continue;
2083 }
2084
2085 replaced = 0;
2086 max_level = level;
2087
2088 ret = walk_down_reloc_tree(reloc_root, path, &level);
2089 if (ret < 0) {
2090 err = ret;
2091 goto out;
2092 }
2093 if (ret > 0)
2094 break;
2095
2096 if (!find_next_key(path, level, &key) &&
2097 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2098 ret = 0;
2099 } else {
2100 ret = replace_path(trans, root, reloc_root, path,
2101 &next_key, level, max_level);
2102 }
2103 if (ret < 0) {
2104 err = ret;
2105 goto out;
2106 }
2107
2108 if (ret > 0) {
2109 level = ret;
2110 btrfs_node_key_to_cpu(path->nodes[level], &key,
2111 path->slots[level]);
2112 replaced = 1;
2113 }
2114
2115 ret = walk_up_reloc_tree(reloc_root, path, &level);
2116 if (ret > 0)
2117 break;
2118
2119 BUG_ON(level == 0);
2120 /*
2121 * save the merging progress in the drop_progress.
2122 * this is OK since root refs == 1 in this case.
2123 */
2124 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2125 path->slots[level]);
2126 root_item->drop_level = level;
2127
2128 nr = trans->blocks_used;
2129 btrfs_end_transaction_throttle(trans, root);
2130
2131 btrfs_btree_balance_dirty(root, nr);
2132
2133 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2134 invalidate_extent_cache(root, &key, &next_key);
2135 }
2136
2137 /*
2138 * handle the case only one block in the fs tree need to be
2139 * relocated and the block is tree root.
2140 */
2141 leaf = btrfs_lock_root_node(root);
2142 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2143 btrfs_tree_unlock(leaf);
2144 free_extent_buffer(leaf);
2145 if (ret < 0)
2146 err = ret;
2147 out:
2148 btrfs_free_path(path);
2149
2150 if (err == 0) {
2151 memset(&root_item->drop_progress, 0,
2152 sizeof(root_item->drop_progress));
2153 root_item->drop_level = 0;
2154 btrfs_set_root_refs(root_item, 0);
2155 btrfs_update_reloc_root(trans, root);
2156 }
2157
2158 nr = trans->blocks_used;
2159 btrfs_end_transaction_throttle(trans, root);
2160
2161 btrfs_btree_balance_dirty(root, nr);
2162
2163 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2164 invalidate_extent_cache(root, &key, &next_key);
2165
2166 return err;
2167 }
2168
2169 static noinline_for_stack
2170 int prepare_to_merge(struct reloc_control *rc, int err)
2171 {
2172 struct btrfs_root *root = rc->extent_root;
2173 struct btrfs_root *reloc_root;
2174 struct btrfs_trans_handle *trans;
2175 LIST_HEAD(reloc_roots);
2176 u64 num_bytes = 0;
2177 int ret;
2178
2179 mutex_lock(&root->fs_info->reloc_mutex);
2180 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2181 rc->merging_rsv_size += rc->nodes_relocated * 2;
2182 mutex_unlock(&root->fs_info->reloc_mutex);
2183
2184 again:
2185 if (!err) {
2186 num_bytes = rc->merging_rsv_size;
2187 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2188 if (ret)
2189 err = ret;
2190 }
2191
2192 trans = btrfs_join_transaction(rc->extent_root);
2193 if (IS_ERR(trans)) {
2194 if (!err)
2195 btrfs_block_rsv_release(rc->extent_root,
2196 rc->block_rsv, num_bytes);
2197 return PTR_ERR(trans);
2198 }
2199
2200 if (!err) {
2201 if (num_bytes != rc->merging_rsv_size) {
2202 btrfs_end_transaction(trans, rc->extent_root);
2203 btrfs_block_rsv_release(rc->extent_root,
2204 rc->block_rsv, num_bytes);
2205 goto again;
2206 }
2207 }
2208
2209 rc->merge_reloc_tree = 1;
2210
2211 while (!list_empty(&rc->reloc_roots)) {
2212 reloc_root = list_entry(rc->reloc_roots.next,
2213 struct btrfs_root, root_list);
2214 list_del_init(&reloc_root->root_list);
2215
2216 root = read_fs_root(reloc_root->fs_info,
2217 reloc_root->root_key.offset);
2218 BUG_ON(IS_ERR(root));
2219 BUG_ON(root->reloc_root != reloc_root);
2220
2221 /*
2222 * set reference count to 1, so btrfs_recover_relocation
2223 * knows it should resumes merging
2224 */
2225 if (!err)
2226 btrfs_set_root_refs(&reloc_root->root_item, 1);
2227 btrfs_update_reloc_root(trans, root);
2228
2229 list_add(&reloc_root->root_list, &reloc_roots);
2230 }
2231
2232 list_splice(&reloc_roots, &rc->reloc_roots);
2233
2234 if (!err)
2235 btrfs_commit_transaction(trans, rc->extent_root);
2236 else
2237 btrfs_end_transaction(trans, rc->extent_root);
2238 return err;
2239 }
2240
2241 static noinline_for_stack
2242 int merge_reloc_roots(struct reloc_control *rc)
2243 {
2244 struct btrfs_root *root;
2245 struct btrfs_root *reloc_root;
2246 LIST_HEAD(reloc_roots);
2247 int found = 0;
2248 int ret;
2249 again:
2250 root = rc->extent_root;
2251
2252 /*
2253 * this serializes us with btrfs_record_root_in_transaction,
2254 * we have to make sure nobody is in the middle of
2255 * adding their roots to the list while we are
2256 * doing this splice
2257 */
2258 mutex_lock(&root->fs_info->reloc_mutex);
2259 list_splice_init(&rc->reloc_roots, &reloc_roots);
2260 mutex_unlock(&root->fs_info->reloc_mutex);
2261
2262 while (!list_empty(&reloc_roots)) {
2263 found = 1;
2264 reloc_root = list_entry(reloc_roots.next,
2265 struct btrfs_root, root_list);
2266
2267 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2268 root = read_fs_root(reloc_root->fs_info,
2269 reloc_root->root_key.offset);
2270 BUG_ON(IS_ERR(root));
2271 BUG_ON(root->reloc_root != reloc_root);
2272
2273 ret = merge_reloc_root(rc, root);
2274 BUG_ON(ret);
2275 } else {
2276 list_del_init(&reloc_root->root_list);
2277 }
2278 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2279 BUG_ON(ret < 0);
2280 }
2281
2282 if (found) {
2283 found = 0;
2284 goto again;
2285 }
2286 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2287 return 0;
2288 }
2289
2290 static void free_block_list(struct rb_root *blocks)
2291 {
2292 struct tree_block *block;
2293 struct rb_node *rb_node;
2294 while ((rb_node = rb_first(blocks))) {
2295 block = rb_entry(rb_node, struct tree_block, rb_node);
2296 rb_erase(rb_node, blocks);
2297 kfree(block);
2298 }
2299 }
2300
2301 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2302 struct btrfs_root *reloc_root)
2303 {
2304 struct btrfs_root *root;
2305
2306 if (reloc_root->last_trans == trans->transid)
2307 return 0;
2308
2309 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2310 BUG_ON(IS_ERR(root));
2311 BUG_ON(root->reloc_root != reloc_root);
2312
2313 return btrfs_record_root_in_trans(trans, root);
2314 }
2315
2316 static noinline_for_stack
2317 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2318 struct reloc_control *rc,
2319 struct backref_node *node,
2320 struct backref_edge *edges[], int *nr)
2321 {
2322 struct backref_node *next;
2323 struct btrfs_root *root;
2324 int index = 0;
2325
2326 next = node;
2327 while (1) {
2328 cond_resched();
2329 next = walk_up_backref(next, edges, &index);
2330 root = next->root;
2331 BUG_ON(!root);
2332 BUG_ON(!root->ref_cows);
2333
2334 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2335 record_reloc_root_in_trans(trans, root);
2336 break;
2337 }
2338
2339 btrfs_record_root_in_trans(trans, root);
2340 root = root->reloc_root;
2341
2342 if (next->new_bytenr != root->node->start) {
2343 BUG_ON(next->new_bytenr);
2344 BUG_ON(!list_empty(&next->list));
2345 next->new_bytenr = root->node->start;
2346 next->root = root;
2347 list_add_tail(&next->list,
2348 &rc->backref_cache.changed);
2349 __mark_block_processed(rc, next);
2350 break;
2351 }
2352
2353 WARN_ON(1);
2354 root = NULL;
2355 next = walk_down_backref(edges, &index);
2356 if (!next || next->level <= node->level)
2357 break;
2358 }
2359 if (!root)
2360 return NULL;
2361
2362 *nr = index;
2363 next = node;
2364 /* setup backref node path for btrfs_reloc_cow_block */
2365 while (1) {
2366 rc->backref_cache.path[next->level] = next;
2367 if (--index < 0)
2368 break;
2369 next = edges[index]->node[UPPER];
2370 }
2371 return root;
2372 }
2373
2374 /*
2375 * select a tree root for relocation. return NULL if the block
2376 * is reference counted. we should use do_relocation() in this
2377 * case. return a tree root pointer if the block isn't reference
2378 * counted. return -ENOENT if the block is root of reloc tree.
2379 */
2380 static noinline_for_stack
2381 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2382 struct backref_node *node)
2383 {
2384 struct backref_node *next;
2385 struct btrfs_root *root;
2386 struct btrfs_root *fs_root = NULL;
2387 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2388 int index = 0;
2389
2390 next = node;
2391 while (1) {
2392 cond_resched();
2393 next = walk_up_backref(next, edges, &index);
2394 root = next->root;
2395 BUG_ON(!root);
2396
2397 /* no other choice for non-references counted tree */
2398 if (!root->ref_cows)
2399 return root;
2400
2401 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2402 fs_root = root;
2403
2404 if (next != node)
2405 return NULL;
2406
2407 next = walk_down_backref(edges, &index);
2408 if (!next || next->level <= node->level)
2409 break;
2410 }
2411
2412 if (!fs_root)
2413 return ERR_PTR(-ENOENT);
2414 return fs_root;
2415 }
2416
2417 static noinline_for_stack
2418 u64 calcu_metadata_size(struct reloc_control *rc,
2419 struct backref_node *node, int reserve)
2420 {
2421 struct backref_node *next = node;
2422 struct backref_edge *edge;
2423 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2424 u64 num_bytes = 0;
2425 int index = 0;
2426
2427 BUG_ON(reserve && node->processed);
2428
2429 while (next) {
2430 cond_resched();
2431 while (1) {
2432 if (next->processed && (reserve || next != node))
2433 break;
2434
2435 num_bytes += btrfs_level_size(rc->extent_root,
2436 next->level);
2437
2438 if (list_empty(&next->upper))
2439 break;
2440
2441 edge = list_entry(next->upper.next,
2442 struct backref_edge, list[LOWER]);
2443 edges[index++] = edge;
2444 next = edge->node[UPPER];
2445 }
2446 next = walk_down_backref(edges, &index);
2447 }
2448 return num_bytes;
2449 }
2450
2451 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2452 struct reloc_control *rc,
2453 struct backref_node *node)
2454 {
2455 struct btrfs_root *root = rc->extent_root;
2456 u64 num_bytes;
2457 int ret;
2458
2459 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2460
2461 trans->block_rsv = rc->block_rsv;
2462 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2463 if (ret) {
2464 if (ret == -EAGAIN)
2465 rc->commit_transaction = 1;
2466 return ret;
2467 }
2468
2469 return 0;
2470 }
2471
2472 static void release_metadata_space(struct reloc_control *rc,
2473 struct backref_node *node)
2474 {
2475 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2476 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2477 }
2478
2479 /*
2480 * relocate a block tree, and then update pointers in upper level
2481 * blocks that reference the block to point to the new location.
2482 *
2483 * if called by link_to_upper, the block has already been relocated.
2484 * in that case this function just updates pointers.
2485 */
2486 static int do_relocation(struct btrfs_trans_handle *trans,
2487 struct reloc_control *rc,
2488 struct backref_node *node,
2489 struct btrfs_key *key,
2490 struct btrfs_path *path, int lowest)
2491 {
2492 struct backref_node *upper;
2493 struct backref_edge *edge;
2494 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2495 struct btrfs_root *root;
2496 struct extent_buffer *eb;
2497 u32 blocksize;
2498 u64 bytenr;
2499 u64 generation;
2500 int nr;
2501 int slot;
2502 int ret;
2503 int err = 0;
2504
2505 BUG_ON(lowest && node->eb);
2506
2507 path->lowest_level = node->level + 1;
2508 rc->backref_cache.path[node->level] = node;
2509 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2510 cond_resched();
2511
2512 upper = edge->node[UPPER];
2513 root = select_reloc_root(trans, rc, upper, edges, &nr);
2514 BUG_ON(!root);
2515
2516 if (upper->eb && !upper->locked) {
2517 if (!lowest) {
2518 ret = btrfs_bin_search(upper->eb, key,
2519 upper->level, &slot);
2520 BUG_ON(ret);
2521 bytenr = btrfs_node_blockptr(upper->eb, slot);
2522 if (node->eb->start == bytenr)
2523 goto next;
2524 }
2525 drop_node_buffer(upper);
2526 }
2527
2528 if (!upper->eb) {
2529 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2530 if (ret < 0) {
2531 err = ret;
2532 break;
2533 }
2534 BUG_ON(ret > 0);
2535
2536 if (!upper->eb) {
2537 upper->eb = path->nodes[upper->level];
2538 path->nodes[upper->level] = NULL;
2539 } else {
2540 BUG_ON(upper->eb != path->nodes[upper->level]);
2541 }
2542
2543 upper->locked = 1;
2544 path->locks[upper->level] = 0;
2545
2546 slot = path->slots[upper->level];
2547 btrfs_release_path(path);
2548 } else {
2549 ret = btrfs_bin_search(upper->eb, key, upper->level,
2550 &slot);
2551 BUG_ON(ret);
2552 }
2553
2554 bytenr = btrfs_node_blockptr(upper->eb, slot);
2555 if (lowest) {
2556 BUG_ON(bytenr != node->bytenr);
2557 } else {
2558 if (node->eb->start == bytenr)
2559 goto next;
2560 }
2561
2562 blocksize = btrfs_level_size(root, node->level);
2563 generation = btrfs_node_ptr_generation(upper->eb, slot);
2564 eb = read_tree_block(root, bytenr, blocksize, generation);
2565 if (!eb) {
2566 err = -EIO;
2567 goto next;
2568 }
2569 btrfs_tree_lock(eb);
2570 btrfs_set_lock_blocking(eb);
2571
2572 if (!node->eb) {
2573 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2574 slot, &eb);
2575 btrfs_tree_unlock(eb);
2576 free_extent_buffer(eb);
2577 if (ret < 0) {
2578 err = ret;
2579 goto next;
2580 }
2581 BUG_ON(node->eb != eb);
2582 } else {
2583 btrfs_set_node_blockptr(upper->eb, slot,
2584 node->eb->start);
2585 btrfs_set_node_ptr_generation(upper->eb, slot,
2586 trans->transid);
2587 btrfs_mark_buffer_dirty(upper->eb);
2588
2589 ret = btrfs_inc_extent_ref(trans, root,
2590 node->eb->start, blocksize,
2591 upper->eb->start,
2592 btrfs_header_owner(upper->eb),
2593 node->level, 0, 1);
2594 BUG_ON(ret);
2595
2596 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2597 BUG_ON(ret);
2598 }
2599 next:
2600 if (!upper->pending)
2601 drop_node_buffer(upper);
2602 else
2603 unlock_node_buffer(upper);
2604 if (err)
2605 break;
2606 }
2607
2608 if (!err && node->pending) {
2609 drop_node_buffer(node);
2610 list_move_tail(&node->list, &rc->backref_cache.changed);
2611 node->pending = 0;
2612 }
2613
2614 path->lowest_level = 0;
2615 BUG_ON(err == -ENOSPC);
2616 return err;
2617 }
2618
2619 static int link_to_upper(struct btrfs_trans_handle *trans,
2620 struct reloc_control *rc,
2621 struct backref_node *node,
2622 struct btrfs_path *path)
2623 {
2624 struct btrfs_key key;
2625
2626 btrfs_node_key_to_cpu(node->eb, &key, 0);
2627 return do_relocation(trans, rc, node, &key, path, 0);
2628 }
2629
2630 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2631 struct reloc_control *rc,
2632 struct btrfs_path *path, int err)
2633 {
2634 LIST_HEAD(list);
2635 struct backref_cache *cache = &rc->backref_cache;
2636 struct backref_node *node;
2637 int level;
2638 int ret;
2639
2640 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2641 while (!list_empty(&cache->pending[level])) {
2642 node = list_entry(cache->pending[level].next,
2643 struct backref_node, list);
2644 list_move_tail(&node->list, &list);
2645 BUG_ON(!node->pending);
2646
2647 if (!err) {
2648 ret = link_to_upper(trans, rc, node, path);
2649 if (ret < 0)
2650 err = ret;
2651 }
2652 }
2653 list_splice_init(&list, &cache->pending[level]);
2654 }
2655 return err;
2656 }
2657
2658 static void mark_block_processed(struct reloc_control *rc,
2659 u64 bytenr, u32 blocksize)
2660 {
2661 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2662 EXTENT_DIRTY, GFP_NOFS);
2663 }
2664
2665 static void __mark_block_processed(struct reloc_control *rc,
2666 struct backref_node *node)
2667 {
2668 u32 blocksize;
2669 if (node->level == 0 ||
2670 in_block_group(node->bytenr, rc->block_group)) {
2671 blocksize = btrfs_level_size(rc->extent_root, node->level);
2672 mark_block_processed(rc, node->bytenr, blocksize);
2673 }
2674 node->processed = 1;
2675 }
2676
2677 /*
2678 * mark a block and all blocks directly/indirectly reference the block
2679 * as processed.
2680 */
2681 static void update_processed_blocks(struct reloc_control *rc,
2682 struct backref_node *node)
2683 {
2684 struct backref_node *next = node;
2685 struct backref_edge *edge;
2686 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2687 int index = 0;
2688
2689 while (next) {
2690 cond_resched();
2691 while (1) {
2692 if (next->processed)
2693 break;
2694
2695 __mark_block_processed(rc, next);
2696
2697 if (list_empty(&next->upper))
2698 break;
2699
2700 edge = list_entry(next->upper.next,
2701 struct backref_edge, list[LOWER]);
2702 edges[index++] = edge;
2703 next = edge->node[UPPER];
2704 }
2705 next = walk_down_backref(edges, &index);
2706 }
2707 }
2708
2709 static int tree_block_processed(u64 bytenr, u32 blocksize,
2710 struct reloc_control *rc)
2711 {
2712 if (test_range_bit(&rc->processed_blocks, bytenr,
2713 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2714 return 1;
2715 return 0;
2716 }
2717
2718 static int get_tree_block_key(struct reloc_control *rc,
2719 struct tree_block *block)
2720 {
2721 struct extent_buffer *eb;
2722
2723 BUG_ON(block->key_ready);
2724 eb = read_tree_block(rc->extent_root, block->bytenr,
2725 block->key.objectid, block->key.offset);
2726 BUG_ON(!eb);
2727 WARN_ON(btrfs_header_level(eb) != block->level);
2728 if (block->level == 0)
2729 btrfs_item_key_to_cpu(eb, &block->key, 0);
2730 else
2731 btrfs_node_key_to_cpu(eb, &block->key, 0);
2732 free_extent_buffer(eb);
2733 block->key_ready = 1;
2734 return 0;
2735 }
2736
2737 static int reada_tree_block(struct reloc_control *rc,
2738 struct tree_block *block)
2739 {
2740 BUG_ON(block->key_ready);
2741 readahead_tree_block(rc->extent_root, block->bytenr,
2742 block->key.objectid, block->key.offset);
2743 return 0;
2744 }
2745
2746 /*
2747 * helper function to relocate a tree block
2748 */
2749 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2750 struct reloc_control *rc,
2751 struct backref_node *node,
2752 struct btrfs_key *key,
2753 struct btrfs_path *path)
2754 {
2755 struct btrfs_root *root;
2756 int release = 0;
2757 int ret = 0;
2758
2759 if (!node)
2760 return 0;
2761
2762 BUG_ON(node->processed);
2763 root = select_one_root(trans, node);
2764 if (root == ERR_PTR(-ENOENT)) {
2765 update_processed_blocks(rc, node);
2766 goto out;
2767 }
2768
2769 if (!root || root->ref_cows) {
2770 ret = reserve_metadata_space(trans, rc, node);
2771 if (ret)
2772 goto out;
2773 release = 1;
2774 }
2775
2776 if (root) {
2777 if (root->ref_cows) {
2778 BUG_ON(node->new_bytenr);
2779 BUG_ON(!list_empty(&node->list));
2780 btrfs_record_root_in_trans(trans, root);
2781 root = root->reloc_root;
2782 node->new_bytenr = root->node->start;
2783 node->root = root;
2784 list_add_tail(&node->list, &rc->backref_cache.changed);
2785 } else {
2786 path->lowest_level = node->level;
2787 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2788 btrfs_release_path(path);
2789 if (ret > 0)
2790 ret = 0;
2791 }
2792 if (!ret)
2793 update_processed_blocks(rc, node);
2794 } else {
2795 ret = do_relocation(trans, rc, node, key, path, 1);
2796 }
2797 out:
2798 if (ret || node->level == 0 || node->cowonly) {
2799 if (release)
2800 release_metadata_space(rc, node);
2801 remove_backref_node(&rc->backref_cache, node);
2802 }
2803 return ret;
2804 }
2805
2806 /*
2807 * relocate a list of blocks
2808 */
2809 static noinline_for_stack
2810 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2811 struct reloc_control *rc, struct rb_root *blocks)
2812 {
2813 struct backref_node *node;
2814 struct btrfs_path *path;
2815 struct tree_block *block;
2816 struct rb_node *rb_node;
2817 int ret;
2818 int err = 0;
2819
2820 path = btrfs_alloc_path();
2821 if (!path)
2822 return -ENOMEM;
2823
2824 rb_node = rb_first(blocks);
2825 while (rb_node) {
2826 block = rb_entry(rb_node, struct tree_block, rb_node);
2827 if (!block->key_ready)
2828 reada_tree_block(rc, block);
2829 rb_node = rb_next(rb_node);
2830 }
2831
2832 rb_node = rb_first(blocks);
2833 while (rb_node) {
2834 block = rb_entry(rb_node, struct tree_block, rb_node);
2835 if (!block->key_ready)
2836 get_tree_block_key(rc, block);
2837 rb_node = rb_next(rb_node);
2838 }
2839
2840 rb_node = rb_first(blocks);
2841 while (rb_node) {
2842 block = rb_entry(rb_node, struct tree_block, rb_node);
2843
2844 node = build_backref_tree(rc, &block->key,
2845 block->level, block->bytenr);
2846 if (IS_ERR(node)) {
2847 err = PTR_ERR(node);
2848 goto out;
2849 }
2850
2851 ret = relocate_tree_block(trans, rc, node, &block->key,
2852 path);
2853 if (ret < 0) {
2854 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2855 err = ret;
2856 goto out;
2857 }
2858 rb_node = rb_next(rb_node);
2859 }
2860 out:
2861 free_block_list(blocks);
2862 err = finish_pending_nodes(trans, rc, path, err);
2863
2864 btrfs_free_path(path);
2865 return err;
2866 }
2867
2868 static noinline_for_stack
2869 int prealloc_file_extent_cluster(struct inode *inode,
2870 struct file_extent_cluster *cluster)
2871 {
2872 u64 alloc_hint = 0;
2873 u64 start;
2874 u64 end;
2875 u64 offset = BTRFS_I(inode)->index_cnt;
2876 u64 num_bytes;
2877 int nr = 0;
2878 int ret = 0;
2879
2880 BUG_ON(cluster->start != cluster->boundary[0]);
2881 mutex_lock(&inode->i_mutex);
2882
2883 ret = btrfs_check_data_free_space(inode, cluster->end +
2884 1 - cluster->start);
2885 if (ret)
2886 goto out;
2887
2888 while (nr < cluster->nr) {
2889 start = cluster->boundary[nr] - offset;
2890 if (nr + 1 < cluster->nr)
2891 end = cluster->boundary[nr + 1] - 1 - offset;
2892 else
2893 end = cluster->end - offset;
2894
2895 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2896 num_bytes = end + 1 - start;
2897 ret = btrfs_prealloc_file_range(inode, 0, start,
2898 num_bytes, num_bytes,
2899 end + 1, &alloc_hint);
2900 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2901 if (ret)
2902 break;
2903 nr++;
2904 }
2905 btrfs_free_reserved_data_space(inode, cluster->end +
2906 1 - cluster->start);
2907 out:
2908 mutex_unlock(&inode->i_mutex);
2909 return ret;
2910 }
2911
2912 static noinline_for_stack
2913 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2914 u64 block_start)
2915 {
2916 struct btrfs_root *root = BTRFS_I(inode)->root;
2917 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2918 struct extent_map *em;
2919 int ret = 0;
2920
2921 em = alloc_extent_map();
2922 if (!em)
2923 return -ENOMEM;
2924
2925 em->start = start;
2926 em->len = end + 1 - start;
2927 em->block_len = em->len;
2928 em->block_start = block_start;
2929 em->bdev = root->fs_info->fs_devices->latest_bdev;
2930 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2931
2932 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2933 while (1) {
2934 write_lock(&em_tree->lock);
2935 ret = add_extent_mapping(em_tree, em);
2936 write_unlock(&em_tree->lock);
2937 if (ret != -EEXIST) {
2938 free_extent_map(em);
2939 break;
2940 }
2941 btrfs_drop_extent_cache(inode, start, end, 0);
2942 }
2943 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2944 return ret;
2945 }
2946
2947 static int relocate_file_extent_cluster(struct inode *inode,
2948 struct file_extent_cluster *cluster)
2949 {
2950 u64 page_start;
2951 u64 page_end;
2952 u64 offset = BTRFS_I(inode)->index_cnt;
2953 unsigned long index;
2954 unsigned long last_index;
2955 struct page *page;
2956 struct file_ra_state *ra;
2957 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2958 int nr = 0;
2959 int ret = 0;
2960
2961 if (!cluster->nr)
2962 return 0;
2963
2964 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2965 if (!ra)
2966 return -ENOMEM;
2967
2968 ret = prealloc_file_extent_cluster(inode, cluster);
2969 if (ret)
2970 goto out;
2971
2972 file_ra_state_init(ra, inode->i_mapping);
2973
2974 ret = setup_extent_mapping(inode, cluster->start - offset,
2975 cluster->end - offset, cluster->start);
2976 if (ret)
2977 goto out;
2978
2979 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2980 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2981 while (index <= last_index) {
2982 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2983 if (ret)
2984 goto out;
2985
2986 page = find_lock_page(inode->i_mapping, index);
2987 if (!page) {
2988 page_cache_sync_readahead(inode->i_mapping,
2989 ra, NULL, index,
2990 last_index + 1 - index);
2991 page = find_or_create_page(inode->i_mapping, index,
2992 mask);
2993 if (!page) {
2994 btrfs_delalloc_release_metadata(inode,
2995 PAGE_CACHE_SIZE);
2996 ret = -ENOMEM;
2997 goto out;
2998 }
2999 }
3000
3001 if (PageReadahead(page)) {
3002 page_cache_async_readahead(inode->i_mapping,
3003 ra, NULL, page, index,
3004 last_index + 1 - index);
3005 }
3006
3007 if (!PageUptodate(page)) {
3008 btrfs_readpage(NULL, page);
3009 lock_page(page);
3010 if (!PageUptodate(page)) {
3011 unlock_page(page);
3012 page_cache_release(page);
3013 btrfs_delalloc_release_metadata(inode,
3014 PAGE_CACHE_SIZE);
3015 ret = -EIO;
3016 goto out;
3017 }
3018 }
3019
3020 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
3021 page_end = page_start + PAGE_CACHE_SIZE - 1;
3022
3023 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3024
3025 set_page_extent_mapped(page);
3026
3027 if (nr < cluster->nr &&
3028 page_start + offset == cluster->boundary[nr]) {
3029 set_extent_bits(&BTRFS_I(inode)->io_tree,
3030 page_start, page_end,
3031 EXTENT_BOUNDARY, GFP_NOFS);
3032 nr++;
3033 }
3034
3035 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3036 set_page_dirty(page);
3037
3038 unlock_extent(&BTRFS_I(inode)->io_tree,
3039 page_start, page_end);
3040 unlock_page(page);
3041 page_cache_release(page);
3042
3043 index++;
3044 balance_dirty_pages_ratelimited(inode->i_mapping);
3045 btrfs_throttle(BTRFS_I(inode)->root);
3046 }
3047 WARN_ON(nr != cluster->nr);
3048 out:
3049 kfree(ra);
3050 return ret;
3051 }
3052
3053 static noinline_for_stack
3054 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3055 struct file_extent_cluster *cluster)
3056 {
3057 int ret;
3058
3059 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3060 ret = relocate_file_extent_cluster(inode, cluster);
3061 if (ret)
3062 return ret;
3063 cluster->nr = 0;
3064 }
3065
3066 if (!cluster->nr)
3067 cluster->start = extent_key->objectid;
3068 else
3069 BUG_ON(cluster->nr >= MAX_EXTENTS);
3070 cluster->end = extent_key->objectid + extent_key->offset - 1;
3071 cluster->boundary[cluster->nr] = extent_key->objectid;
3072 cluster->nr++;
3073
3074 if (cluster->nr >= MAX_EXTENTS) {
3075 ret = relocate_file_extent_cluster(inode, cluster);
3076 if (ret)
3077 return ret;
3078 cluster->nr = 0;
3079 }
3080 return 0;
3081 }
3082
3083 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3084 static int get_ref_objectid_v0(struct reloc_control *rc,
3085 struct btrfs_path *path,
3086 struct btrfs_key *extent_key,
3087 u64 *ref_objectid, int *path_change)
3088 {
3089 struct btrfs_key key;
3090 struct extent_buffer *leaf;
3091 struct btrfs_extent_ref_v0 *ref0;
3092 int ret;
3093 int slot;
3094
3095 leaf = path->nodes[0];
3096 slot = path->slots[0];
3097 while (1) {
3098 if (slot >= btrfs_header_nritems(leaf)) {
3099 ret = btrfs_next_leaf(rc->extent_root, path);
3100 if (ret < 0)
3101 return ret;
3102 BUG_ON(ret > 0);
3103 leaf = path->nodes[0];
3104 slot = path->slots[0];
3105 if (path_change)
3106 *path_change = 1;
3107 }
3108 btrfs_item_key_to_cpu(leaf, &key, slot);
3109 if (key.objectid != extent_key->objectid)
3110 return -ENOENT;
3111
3112 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3113 slot++;
3114 continue;
3115 }
3116 ref0 = btrfs_item_ptr(leaf, slot,
3117 struct btrfs_extent_ref_v0);
3118 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3119 break;
3120 }
3121 return 0;
3122 }
3123 #endif
3124
3125 /*
3126 * helper to add a tree block to the list.
3127 * the major work is getting the generation and level of the block
3128 */
3129 static int add_tree_block(struct reloc_control *rc,
3130 struct btrfs_key *extent_key,
3131 struct btrfs_path *path,
3132 struct rb_root *blocks)
3133 {
3134 struct extent_buffer *eb;
3135 struct btrfs_extent_item *ei;
3136 struct btrfs_tree_block_info *bi;
3137 struct tree_block *block;
3138 struct rb_node *rb_node;
3139 u32 item_size;
3140 int level = -1;
3141 int generation;
3142
3143 eb = path->nodes[0];
3144 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3145
3146 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3147 ei = btrfs_item_ptr(eb, path->slots[0],
3148 struct btrfs_extent_item);
3149 bi = (struct btrfs_tree_block_info *)(ei + 1);
3150 generation = btrfs_extent_generation(eb, ei);
3151 level = btrfs_tree_block_level(eb, bi);
3152 } else {
3153 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3154 u64 ref_owner;
3155 int ret;
3156
3157 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3158 ret = get_ref_objectid_v0(rc, path, extent_key,
3159 &ref_owner, NULL);
3160 if (ret < 0)
3161 return ret;
3162 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3163 level = (int)ref_owner;
3164 /* FIXME: get real generation */
3165 generation = 0;
3166 #else
3167 BUG();
3168 #endif
3169 }
3170
3171 btrfs_release_path(path);
3172
3173 BUG_ON(level == -1);
3174
3175 block = kmalloc(sizeof(*block), GFP_NOFS);
3176 if (!block)
3177 return -ENOMEM;
3178
3179 block->bytenr = extent_key->objectid;
3180 block->key.objectid = extent_key->offset;
3181 block->key.offset = generation;
3182 block->level = level;
3183 block->key_ready = 0;
3184
3185 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3186 if (rb_node)
3187 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3188
3189 return 0;
3190 }
3191
3192 /*
3193 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3194 */
3195 static int __add_tree_block(struct reloc_control *rc,
3196 u64 bytenr, u32 blocksize,
3197 struct rb_root *blocks)
3198 {
3199 struct btrfs_path *path;
3200 struct btrfs_key key;
3201 int ret;
3202
3203 if (tree_block_processed(bytenr, blocksize, rc))
3204 return 0;
3205
3206 if (tree_search(blocks, bytenr))
3207 return 0;
3208
3209 path = btrfs_alloc_path();
3210 if (!path)
3211 return -ENOMEM;
3212
3213 key.objectid = bytenr;
3214 key.type = BTRFS_EXTENT_ITEM_KEY;
3215 key.offset = blocksize;
3216
3217 path->search_commit_root = 1;
3218 path->skip_locking = 1;
3219 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3220 if (ret < 0)
3221 goto out;
3222 BUG_ON(ret);
3223
3224 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3225 ret = add_tree_block(rc, &key, path, blocks);
3226 out:
3227 btrfs_free_path(path);
3228 return ret;
3229 }
3230
3231 /*
3232 * helper to check if the block use full backrefs for pointers in it
3233 */
3234 static int block_use_full_backref(struct reloc_control *rc,
3235 struct extent_buffer *eb)
3236 {
3237 u64 flags;
3238 int ret;
3239
3240 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3241 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3242 return 1;
3243
3244 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3245 eb->start, eb->len, NULL, &flags);
3246 BUG_ON(ret);
3247
3248 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3249 ret = 1;
3250 else
3251 ret = 0;
3252 return ret;
3253 }
3254
3255 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3256 struct inode *inode, u64 ino)
3257 {
3258 struct btrfs_key key;
3259 struct btrfs_path *path;
3260 struct btrfs_root *root = fs_info->tree_root;
3261 struct btrfs_trans_handle *trans;
3262 unsigned long nr;
3263 int ret = 0;
3264
3265 if (inode)
3266 goto truncate;
3267
3268 key.objectid = ino;
3269 key.type = BTRFS_INODE_ITEM_KEY;
3270 key.offset = 0;
3271
3272 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3273 if (IS_ERR(inode) || is_bad_inode(inode)) {
3274 if (!IS_ERR(inode))
3275 iput(inode);
3276 return -ENOENT;
3277 }
3278
3279 truncate:
3280 path = btrfs_alloc_path();
3281 if (!path) {
3282 ret = -ENOMEM;
3283 goto out;
3284 }
3285
3286 trans = btrfs_join_transaction(root);
3287 if (IS_ERR(trans)) {
3288 btrfs_free_path(path);
3289 ret = PTR_ERR(trans);
3290 goto out;
3291 }
3292
3293 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3294
3295 btrfs_free_path(path);
3296 nr = trans->blocks_used;
3297 btrfs_end_transaction(trans, root);
3298 btrfs_btree_balance_dirty(root, nr);
3299 out:
3300 iput(inode);
3301 return ret;
3302 }
3303
3304 /*
3305 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3306 * this function scans fs tree to find blocks reference the data extent
3307 */
3308 static int find_data_references(struct reloc_control *rc,
3309 struct btrfs_key *extent_key,
3310 struct extent_buffer *leaf,
3311 struct btrfs_extent_data_ref *ref,
3312 struct rb_root *blocks)
3313 {
3314 struct btrfs_path *path;
3315 struct tree_block *block;
3316 struct btrfs_root *root;
3317 struct btrfs_file_extent_item *fi;
3318 struct rb_node *rb_node;
3319 struct btrfs_key key;
3320 u64 ref_root;
3321 u64 ref_objectid;
3322 u64 ref_offset;
3323 u32 ref_count;
3324 u32 nritems;
3325 int err = 0;
3326 int added = 0;
3327 int counted;
3328 int ret;
3329
3330 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3331 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3332 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3333 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3334
3335 /*
3336 * This is an extent belonging to the free space cache, lets just delete
3337 * it and redo the search.
3338 */
3339 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3340 ret = delete_block_group_cache(rc->extent_root->fs_info,
3341 NULL, ref_objectid);
3342 if (ret != -ENOENT)
3343 return ret;
3344 ret = 0;
3345 }
3346
3347 path = btrfs_alloc_path();
3348 if (!path)
3349 return -ENOMEM;
3350 path->reada = 1;
3351
3352 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3353 if (IS_ERR(root)) {
3354 err = PTR_ERR(root);
3355 goto out;
3356 }
3357
3358 key.objectid = ref_objectid;
3359 key.type = BTRFS_EXTENT_DATA_KEY;
3360 if (ref_offset > ((u64)-1 << 32))
3361 key.offset = 0;
3362 else
3363 key.offset = ref_offset;
3364
3365 path->search_commit_root = 1;
3366 path->skip_locking = 1;
3367 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3368 if (ret < 0) {
3369 err = ret;
3370 goto out;
3371 }
3372
3373 leaf = path->nodes[0];
3374 nritems = btrfs_header_nritems(leaf);
3375 /*
3376 * the references in tree blocks that use full backrefs
3377 * are not counted in
3378 */
3379 if (block_use_full_backref(rc, leaf))
3380 counted = 0;
3381 else
3382 counted = 1;
3383 rb_node = tree_search(blocks, leaf->start);
3384 if (rb_node) {
3385 if (counted)
3386 added = 1;
3387 else
3388 path->slots[0] = nritems;
3389 }
3390
3391 while (ref_count > 0) {
3392 while (path->slots[0] >= nritems) {
3393 ret = btrfs_next_leaf(root, path);
3394 if (ret < 0) {
3395 err = ret;
3396 goto out;
3397 }
3398 if (ret > 0) {
3399 WARN_ON(1);
3400 goto out;
3401 }
3402
3403 leaf = path->nodes[0];
3404 nritems = btrfs_header_nritems(leaf);
3405 added = 0;
3406
3407 if (block_use_full_backref(rc, leaf))
3408 counted = 0;
3409 else
3410 counted = 1;
3411 rb_node = tree_search(blocks, leaf->start);
3412 if (rb_node) {
3413 if (counted)
3414 added = 1;
3415 else
3416 path->slots[0] = nritems;
3417 }
3418 }
3419
3420 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3421 if (key.objectid != ref_objectid ||
3422 key.type != BTRFS_EXTENT_DATA_KEY) {
3423 WARN_ON(1);
3424 break;
3425 }
3426
3427 fi = btrfs_item_ptr(leaf, path->slots[0],
3428 struct btrfs_file_extent_item);
3429
3430 if (btrfs_file_extent_type(leaf, fi) ==
3431 BTRFS_FILE_EXTENT_INLINE)
3432 goto next;
3433
3434 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3435 extent_key->objectid)
3436 goto next;
3437
3438 key.offset -= btrfs_file_extent_offset(leaf, fi);
3439 if (key.offset != ref_offset)
3440 goto next;
3441
3442 if (counted)
3443 ref_count--;
3444 if (added)
3445 goto next;
3446
3447 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3448 block = kmalloc(sizeof(*block), GFP_NOFS);
3449 if (!block) {
3450 err = -ENOMEM;
3451 break;
3452 }
3453 block->bytenr = leaf->start;
3454 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3455 block->level = 0;
3456 block->key_ready = 1;
3457 rb_node = tree_insert(blocks, block->bytenr,
3458 &block->rb_node);
3459 if (rb_node)
3460 backref_tree_panic(rb_node, -EEXIST,
3461 block->bytenr);
3462 }
3463 if (counted)
3464 added = 1;
3465 else
3466 path->slots[0] = nritems;
3467 next:
3468 path->slots[0]++;
3469
3470 }
3471 out:
3472 btrfs_free_path(path);
3473 return err;
3474 }
3475
3476 /*
3477 * hepler to find all tree blocks that reference a given data extent
3478 */
3479 static noinline_for_stack
3480 int add_data_references(struct reloc_control *rc,
3481 struct btrfs_key *extent_key,
3482 struct btrfs_path *path,
3483 struct rb_root *blocks)
3484 {
3485 struct btrfs_key key;
3486 struct extent_buffer *eb;
3487 struct btrfs_extent_data_ref *dref;
3488 struct btrfs_extent_inline_ref *iref;
3489 unsigned long ptr;
3490 unsigned long end;
3491 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3492 int ret;
3493 int err = 0;
3494
3495 eb = path->nodes[0];
3496 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3497 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3498 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3499 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3500 ptr = end;
3501 else
3502 #endif
3503 ptr += sizeof(struct btrfs_extent_item);
3504
3505 while (ptr < end) {
3506 iref = (struct btrfs_extent_inline_ref *)ptr;
3507 key.type = btrfs_extent_inline_ref_type(eb, iref);
3508 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3509 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3510 ret = __add_tree_block(rc, key.offset, blocksize,
3511 blocks);
3512 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3513 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3514 ret = find_data_references(rc, extent_key,
3515 eb, dref, blocks);
3516 } else {
3517 BUG();
3518 }
3519 ptr += btrfs_extent_inline_ref_size(key.type);
3520 }
3521 WARN_ON(ptr > end);
3522
3523 while (1) {
3524 cond_resched();
3525 eb = path->nodes[0];
3526 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3527 ret = btrfs_next_leaf(rc->extent_root, path);
3528 if (ret < 0) {
3529 err = ret;
3530 break;
3531 }
3532 if (ret > 0)
3533 break;
3534 eb = path->nodes[0];
3535 }
3536
3537 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3538 if (key.objectid != extent_key->objectid)
3539 break;
3540
3541 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3542 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3543 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3544 #else
3545 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3546 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3547 #endif
3548 ret = __add_tree_block(rc, key.offset, blocksize,
3549 blocks);
3550 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3551 dref = btrfs_item_ptr(eb, path->slots[0],
3552 struct btrfs_extent_data_ref);
3553 ret = find_data_references(rc, extent_key,
3554 eb, dref, blocks);
3555 } else {
3556 ret = 0;
3557 }
3558 if (ret) {
3559 err = ret;
3560 break;
3561 }
3562 path->slots[0]++;
3563 }
3564 btrfs_release_path(path);
3565 if (err)
3566 free_block_list(blocks);
3567 return err;
3568 }
3569
3570 /*
3571 * hepler to find next unprocessed extent
3572 */
3573 static noinline_for_stack
3574 int find_next_extent(struct btrfs_trans_handle *trans,
3575 struct reloc_control *rc, struct btrfs_path *path,
3576 struct btrfs_key *extent_key)
3577 {
3578 struct btrfs_key key;
3579 struct extent_buffer *leaf;
3580 u64 start, end, last;
3581 int ret;
3582
3583 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3584 while (1) {
3585 cond_resched();
3586 if (rc->search_start >= last) {
3587 ret = 1;
3588 break;
3589 }
3590
3591 key.objectid = rc->search_start;
3592 key.type = BTRFS_EXTENT_ITEM_KEY;
3593 key.offset = 0;
3594
3595 path->search_commit_root = 1;
3596 path->skip_locking = 1;
3597 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3598 0, 0);
3599 if (ret < 0)
3600 break;
3601 next:
3602 leaf = path->nodes[0];
3603 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3604 ret = btrfs_next_leaf(rc->extent_root, path);
3605 if (ret != 0)
3606 break;
3607 leaf = path->nodes[0];
3608 }
3609
3610 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3611 if (key.objectid >= last) {
3612 ret = 1;
3613 break;
3614 }
3615
3616 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3617 key.objectid + key.offset <= rc->search_start) {
3618 path->slots[0]++;
3619 goto next;
3620 }
3621
3622 ret = find_first_extent_bit(&rc->processed_blocks,
3623 key.objectid, &start, &end,
3624 EXTENT_DIRTY, NULL);
3625
3626 if (ret == 0 && start <= key.objectid) {
3627 btrfs_release_path(path);
3628 rc->search_start = end + 1;
3629 } else {
3630 rc->search_start = key.objectid + key.offset;
3631 memcpy(extent_key, &key, sizeof(key));
3632 return 0;
3633 }
3634 }
3635 btrfs_release_path(path);
3636 return ret;
3637 }
3638
3639 static void set_reloc_control(struct reloc_control *rc)
3640 {
3641 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3642
3643 mutex_lock(&fs_info->reloc_mutex);
3644 fs_info->reloc_ctl = rc;
3645 mutex_unlock(&fs_info->reloc_mutex);
3646 }
3647
3648 static void unset_reloc_control(struct reloc_control *rc)
3649 {
3650 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3651
3652 mutex_lock(&fs_info->reloc_mutex);
3653 fs_info->reloc_ctl = NULL;
3654 mutex_unlock(&fs_info->reloc_mutex);
3655 }
3656
3657 static int check_extent_flags(u64 flags)
3658 {
3659 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3660 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3661 return 1;
3662 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3663 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3664 return 1;
3665 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3666 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3667 return 1;
3668 return 0;
3669 }
3670
3671 static noinline_for_stack
3672 int prepare_to_relocate(struct reloc_control *rc)
3673 {
3674 struct btrfs_trans_handle *trans;
3675 int ret;
3676
3677 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3678 BTRFS_BLOCK_RSV_TEMP);
3679 if (!rc->block_rsv)
3680 return -ENOMEM;
3681
3682 /*
3683 * reserve some space for creating reloc trees.
3684 * btrfs_init_reloc_root will use them when there
3685 * is no reservation in transaction handle.
3686 */
3687 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3688 rc->extent_root->nodesize * 256);
3689 if (ret)
3690 return ret;
3691
3692 memset(&rc->cluster, 0, sizeof(rc->cluster));
3693 rc->search_start = rc->block_group->key.objectid;
3694 rc->extents_found = 0;
3695 rc->nodes_relocated = 0;
3696 rc->merging_rsv_size = 0;
3697
3698 rc->create_reloc_tree = 1;
3699 set_reloc_control(rc);
3700
3701 trans = btrfs_join_transaction(rc->extent_root);
3702 BUG_ON(IS_ERR(trans));
3703 btrfs_commit_transaction(trans, rc->extent_root);
3704 return 0;
3705 }
3706
3707 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3708 {
3709 struct rb_root blocks = RB_ROOT;
3710 struct btrfs_key key;
3711 struct btrfs_trans_handle *trans = NULL;
3712 struct btrfs_path *path;
3713 struct btrfs_extent_item *ei;
3714 unsigned long nr;
3715 u64 flags;
3716 u32 item_size;
3717 int ret;
3718 int err = 0;
3719 int progress = 0;
3720
3721 path = btrfs_alloc_path();
3722 if (!path)
3723 return -ENOMEM;
3724 path->reada = 1;
3725
3726 ret = prepare_to_relocate(rc);
3727 if (ret) {
3728 err = ret;
3729 goto out_free;
3730 }
3731
3732 while (1) {
3733 progress++;
3734 trans = btrfs_start_transaction(rc->extent_root, 0);
3735 BUG_ON(IS_ERR(trans));
3736 restart:
3737 if (update_backref_cache(trans, &rc->backref_cache)) {
3738 btrfs_end_transaction(trans, rc->extent_root);
3739 continue;
3740 }
3741
3742 ret = find_next_extent(trans, rc, path, &key);
3743 if (ret < 0)
3744 err = ret;
3745 if (ret != 0)
3746 break;
3747
3748 rc->extents_found++;
3749
3750 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3751 struct btrfs_extent_item);
3752 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3753 if (item_size >= sizeof(*ei)) {
3754 flags = btrfs_extent_flags(path->nodes[0], ei);
3755 ret = check_extent_flags(flags);
3756 BUG_ON(ret);
3757
3758 } else {
3759 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3760 u64 ref_owner;
3761 int path_change = 0;
3762
3763 BUG_ON(item_size !=
3764 sizeof(struct btrfs_extent_item_v0));
3765 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3766 &path_change);
3767 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3768 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3769 else
3770 flags = BTRFS_EXTENT_FLAG_DATA;
3771
3772 if (path_change) {
3773 btrfs_release_path(path);
3774
3775 path->search_commit_root = 1;
3776 path->skip_locking = 1;
3777 ret = btrfs_search_slot(NULL, rc->extent_root,
3778 &key, path, 0, 0);
3779 if (ret < 0) {
3780 err = ret;
3781 break;
3782 }
3783 BUG_ON(ret > 0);
3784 }
3785 #else
3786 BUG();
3787 #endif
3788 }
3789
3790 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3791 ret = add_tree_block(rc, &key, path, &blocks);
3792 } else if (rc->stage == UPDATE_DATA_PTRS &&
3793 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3794 ret = add_data_references(rc, &key, path, &blocks);
3795 } else {
3796 btrfs_release_path(path);
3797 ret = 0;
3798 }
3799 if (ret < 0) {
3800 err = ret;
3801 break;
3802 }
3803
3804 if (!RB_EMPTY_ROOT(&blocks)) {
3805 ret = relocate_tree_blocks(trans, rc, &blocks);
3806 if (ret < 0) {
3807 if (ret != -EAGAIN) {
3808 err = ret;
3809 break;
3810 }
3811 rc->extents_found--;
3812 rc->search_start = key.objectid;
3813 }
3814 }
3815
3816 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
3817 if (ret < 0) {
3818 if (ret != -ENOSPC) {
3819 err = ret;
3820 WARN_ON(1);
3821 break;
3822 }
3823 rc->commit_transaction = 1;
3824 }
3825
3826 if (rc->commit_transaction) {
3827 rc->commit_transaction = 0;
3828 ret = btrfs_commit_transaction(trans, rc->extent_root);
3829 BUG_ON(ret);
3830 } else {
3831 nr = trans->blocks_used;
3832 btrfs_end_transaction_throttle(trans, rc->extent_root);
3833 btrfs_btree_balance_dirty(rc->extent_root, nr);
3834 }
3835 trans = NULL;
3836
3837 if (rc->stage == MOVE_DATA_EXTENTS &&
3838 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3839 rc->found_file_extent = 1;
3840 ret = relocate_data_extent(rc->data_inode,
3841 &key, &rc->cluster);
3842 if (ret < 0) {
3843 err = ret;
3844 break;
3845 }
3846 }
3847 }
3848 if (trans && progress && err == -ENOSPC) {
3849 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3850 rc->block_group->flags);
3851 if (ret == 0) {
3852 err = 0;
3853 progress = 0;
3854 goto restart;
3855 }
3856 }
3857
3858 btrfs_release_path(path);
3859 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3860 GFP_NOFS);
3861
3862 if (trans) {
3863 nr = trans->blocks_used;
3864 btrfs_end_transaction_throttle(trans, rc->extent_root);
3865 btrfs_btree_balance_dirty(rc->extent_root, nr);
3866 }
3867
3868 if (!err) {
3869 ret = relocate_file_extent_cluster(rc->data_inode,
3870 &rc->cluster);
3871 if (ret < 0)
3872 err = ret;
3873 }
3874
3875 rc->create_reloc_tree = 0;
3876 set_reloc_control(rc);
3877
3878 backref_cache_cleanup(&rc->backref_cache);
3879 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3880
3881 err = prepare_to_merge(rc, err);
3882
3883 merge_reloc_roots(rc);
3884
3885 rc->merge_reloc_tree = 0;
3886 unset_reloc_control(rc);
3887 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3888
3889 /* get rid of pinned extents */
3890 trans = btrfs_join_transaction(rc->extent_root);
3891 if (IS_ERR(trans))
3892 err = PTR_ERR(trans);
3893 else
3894 btrfs_commit_transaction(trans, rc->extent_root);
3895 out_free:
3896 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3897 btrfs_free_path(path);
3898 return err;
3899 }
3900
3901 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3902 struct btrfs_root *root, u64 objectid)
3903 {
3904 struct btrfs_path *path;
3905 struct btrfs_inode_item *item;
3906 struct extent_buffer *leaf;
3907 int ret;
3908
3909 path = btrfs_alloc_path();
3910 if (!path)
3911 return -ENOMEM;
3912
3913 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3914 if (ret)
3915 goto out;
3916
3917 leaf = path->nodes[0];
3918 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3919 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3920 btrfs_set_inode_generation(leaf, item, 1);
3921 btrfs_set_inode_size(leaf, item, 0);
3922 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3923 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3924 BTRFS_INODE_PREALLOC);
3925 btrfs_mark_buffer_dirty(leaf);
3926 btrfs_release_path(path);
3927 out:
3928 btrfs_free_path(path);
3929 return ret;
3930 }
3931
3932 /*
3933 * helper to create inode for data relocation.
3934 * the inode is in data relocation tree and its link count is 0
3935 */
3936 static noinline_for_stack
3937 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3938 struct btrfs_block_group_cache *group)
3939 {
3940 struct inode *inode = NULL;
3941 struct btrfs_trans_handle *trans;
3942 struct btrfs_root *root;
3943 struct btrfs_key key;
3944 unsigned long nr;
3945 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3946 int err = 0;
3947
3948 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3949 if (IS_ERR(root))
3950 return ERR_CAST(root);
3951
3952 trans = btrfs_start_transaction(root, 6);
3953 if (IS_ERR(trans))
3954 return ERR_CAST(trans);
3955
3956 err = btrfs_find_free_objectid(root, &objectid);
3957 if (err)
3958 goto out;
3959
3960 err = __insert_orphan_inode(trans, root, objectid);
3961 BUG_ON(err);
3962
3963 key.objectid = objectid;
3964 key.type = BTRFS_INODE_ITEM_KEY;
3965 key.offset = 0;
3966 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3967 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3968 BTRFS_I(inode)->index_cnt = group->key.objectid;
3969
3970 err = btrfs_orphan_add(trans, inode);
3971 out:
3972 nr = trans->blocks_used;
3973 btrfs_end_transaction(trans, root);
3974 btrfs_btree_balance_dirty(root, nr);
3975 if (err) {
3976 if (inode)
3977 iput(inode);
3978 inode = ERR_PTR(err);
3979 }
3980 return inode;
3981 }
3982
3983 static struct reloc_control *alloc_reloc_control(void)
3984 {
3985 struct reloc_control *rc;
3986
3987 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3988 if (!rc)
3989 return NULL;
3990
3991 INIT_LIST_HEAD(&rc->reloc_roots);
3992 backref_cache_init(&rc->backref_cache);
3993 mapping_tree_init(&rc->reloc_root_tree);
3994 extent_io_tree_init(&rc->processed_blocks, NULL);
3995 return rc;
3996 }
3997
3998 /*
3999 * function to relocate all extents in a block group.
4000 */
4001 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4002 {
4003 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4004 struct reloc_control *rc;
4005 struct inode *inode;
4006 struct btrfs_path *path;
4007 int ret;
4008 int rw = 0;
4009 int err = 0;
4010
4011 rc = alloc_reloc_control();
4012 if (!rc)
4013 return -ENOMEM;
4014
4015 rc->extent_root = extent_root;
4016
4017 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4018 BUG_ON(!rc->block_group);
4019
4020 if (!rc->block_group->ro) {
4021 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4022 if (ret) {
4023 err = ret;
4024 goto out;
4025 }
4026 rw = 1;
4027 }
4028
4029 path = btrfs_alloc_path();
4030 if (!path) {
4031 err = -ENOMEM;
4032 goto out;
4033 }
4034
4035 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4036 path);
4037 btrfs_free_path(path);
4038
4039 if (!IS_ERR(inode))
4040 ret = delete_block_group_cache(fs_info, inode, 0);
4041 else
4042 ret = PTR_ERR(inode);
4043
4044 if (ret && ret != -ENOENT) {
4045 err = ret;
4046 goto out;
4047 }
4048
4049 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4050 if (IS_ERR(rc->data_inode)) {
4051 err = PTR_ERR(rc->data_inode);
4052 rc->data_inode = NULL;
4053 goto out;
4054 }
4055
4056 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4057 (unsigned long long)rc->block_group->key.objectid,
4058 (unsigned long long)rc->block_group->flags);
4059
4060 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4061 btrfs_wait_ordered_extents(fs_info->tree_root, 0);
4062
4063 while (1) {
4064 mutex_lock(&fs_info->cleaner_mutex);
4065
4066 btrfs_clean_old_snapshots(fs_info->tree_root);
4067 ret = relocate_block_group(rc);
4068
4069 mutex_unlock(&fs_info->cleaner_mutex);
4070 if (ret < 0) {
4071 err = ret;
4072 goto out;
4073 }
4074
4075 if (rc->extents_found == 0)
4076 break;
4077
4078 printk(KERN_INFO "btrfs: found %llu extents\n",
4079 (unsigned long long)rc->extents_found);
4080
4081 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4082 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4083 invalidate_mapping_pages(rc->data_inode->i_mapping,
4084 0, -1);
4085 rc->stage = UPDATE_DATA_PTRS;
4086 }
4087 }
4088
4089 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4090 rc->block_group->key.objectid,
4091 rc->block_group->key.objectid +
4092 rc->block_group->key.offset - 1);
4093
4094 WARN_ON(rc->block_group->pinned > 0);
4095 WARN_ON(rc->block_group->reserved > 0);
4096 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4097 out:
4098 if (err && rw)
4099 btrfs_set_block_group_rw(extent_root, rc->block_group);
4100 iput(rc->data_inode);
4101 btrfs_put_block_group(rc->block_group);
4102 kfree(rc);
4103 return err;
4104 }
4105
4106 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4107 {
4108 struct btrfs_trans_handle *trans;
4109 int ret, err;
4110
4111 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4112 if (IS_ERR(trans))
4113 return PTR_ERR(trans);
4114
4115 memset(&root->root_item.drop_progress, 0,
4116 sizeof(root->root_item.drop_progress));
4117 root->root_item.drop_level = 0;
4118 btrfs_set_root_refs(&root->root_item, 0);
4119 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4120 &root->root_key, &root->root_item);
4121
4122 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4123 if (err)
4124 return err;
4125 return ret;
4126 }
4127
4128 /*
4129 * recover relocation interrupted by system crash.
4130 *
4131 * this function resumes merging reloc trees with corresponding fs trees.
4132 * this is important for keeping the sharing of tree blocks
4133 */
4134 int btrfs_recover_relocation(struct btrfs_root *root)
4135 {
4136 LIST_HEAD(reloc_roots);
4137 struct btrfs_key key;
4138 struct btrfs_root *fs_root;
4139 struct btrfs_root *reloc_root;
4140 struct btrfs_path *path;
4141 struct extent_buffer *leaf;
4142 struct reloc_control *rc = NULL;
4143 struct btrfs_trans_handle *trans;
4144 int ret;
4145 int err = 0;
4146
4147 path = btrfs_alloc_path();
4148 if (!path)
4149 return -ENOMEM;
4150 path->reada = -1;
4151
4152 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4153 key.type = BTRFS_ROOT_ITEM_KEY;
4154 key.offset = (u64)-1;
4155
4156 while (1) {
4157 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4158 path, 0, 0);
4159 if (ret < 0) {
4160 err = ret;
4161 goto out;
4162 }
4163 if (ret > 0) {
4164 if (path->slots[0] == 0)
4165 break;
4166 path->slots[0]--;
4167 }
4168 leaf = path->nodes[0];
4169 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4170 btrfs_release_path(path);
4171
4172 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4173 key.type != BTRFS_ROOT_ITEM_KEY)
4174 break;
4175
4176 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4177 if (IS_ERR(reloc_root)) {
4178 err = PTR_ERR(reloc_root);
4179 goto out;
4180 }
4181
4182 list_add(&reloc_root->root_list, &reloc_roots);
4183
4184 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4185 fs_root = read_fs_root(root->fs_info,
4186 reloc_root->root_key.offset);
4187 if (IS_ERR(fs_root)) {
4188 ret = PTR_ERR(fs_root);
4189 if (ret != -ENOENT) {
4190 err = ret;
4191 goto out;
4192 }
4193 ret = mark_garbage_root(reloc_root);
4194 if (ret < 0) {
4195 err = ret;
4196 goto out;
4197 }
4198 }
4199 }
4200
4201 if (key.offset == 0)
4202 break;
4203
4204 key.offset--;
4205 }
4206 btrfs_release_path(path);
4207
4208 if (list_empty(&reloc_roots))
4209 goto out;
4210
4211 rc = alloc_reloc_control();
4212 if (!rc) {
4213 err = -ENOMEM;
4214 goto out;
4215 }
4216
4217 rc->extent_root = root->fs_info->extent_root;
4218
4219 set_reloc_control(rc);
4220
4221 trans = btrfs_join_transaction(rc->extent_root);
4222 if (IS_ERR(trans)) {
4223 unset_reloc_control(rc);
4224 err = PTR_ERR(trans);
4225 goto out_free;
4226 }
4227
4228 rc->merge_reloc_tree = 1;
4229
4230 while (!list_empty(&reloc_roots)) {
4231 reloc_root = list_entry(reloc_roots.next,
4232 struct btrfs_root, root_list);
4233 list_del(&reloc_root->root_list);
4234
4235 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4236 list_add_tail(&reloc_root->root_list,
4237 &rc->reloc_roots);
4238 continue;
4239 }
4240
4241 fs_root = read_fs_root(root->fs_info,
4242 reloc_root->root_key.offset);
4243 if (IS_ERR(fs_root)) {
4244 err = PTR_ERR(fs_root);
4245 goto out_free;
4246 }
4247
4248 err = __add_reloc_root(reloc_root);
4249 BUG_ON(err < 0); /* -ENOMEM or logic error */
4250 fs_root->reloc_root = reloc_root;
4251 }
4252
4253 err = btrfs_commit_transaction(trans, rc->extent_root);
4254 if (err)
4255 goto out_free;
4256
4257 merge_reloc_roots(rc);
4258
4259 unset_reloc_control(rc);
4260
4261 trans = btrfs_join_transaction(rc->extent_root);
4262 if (IS_ERR(trans))
4263 err = PTR_ERR(trans);
4264 else
4265 err = btrfs_commit_transaction(trans, rc->extent_root);
4266 out_free:
4267 kfree(rc);
4268 out:
4269 while (!list_empty(&reloc_roots)) {
4270 reloc_root = list_entry(reloc_roots.next,
4271 struct btrfs_root, root_list);
4272 list_del(&reloc_root->root_list);
4273 free_extent_buffer(reloc_root->node);
4274 free_extent_buffer(reloc_root->commit_root);
4275 kfree(reloc_root);
4276 }
4277 btrfs_free_path(path);
4278
4279 if (err == 0) {
4280 /* cleanup orphan inode in data relocation tree */
4281 fs_root = read_fs_root(root->fs_info,
4282 BTRFS_DATA_RELOC_TREE_OBJECTID);
4283 if (IS_ERR(fs_root))
4284 err = PTR_ERR(fs_root);
4285 else
4286 err = btrfs_orphan_cleanup(fs_root);
4287 }
4288 return err;
4289 }
4290
4291 /*
4292 * helper to add ordered checksum for data relocation.
4293 *
4294 * cloning checksum properly handles the nodatasum extents.
4295 * it also saves CPU time to re-calculate the checksum.
4296 */
4297 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4298 {
4299 struct btrfs_ordered_sum *sums;
4300 struct btrfs_sector_sum *sector_sum;
4301 struct btrfs_ordered_extent *ordered;
4302 struct btrfs_root *root = BTRFS_I(inode)->root;
4303 size_t offset;
4304 int ret;
4305 u64 disk_bytenr;
4306 LIST_HEAD(list);
4307
4308 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4309 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4310
4311 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4312 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4313 disk_bytenr + len - 1, &list, 0);
4314 if (ret)
4315 goto out;
4316
4317 while (!list_empty(&list)) {
4318 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4319 list_del_init(&sums->list);
4320
4321 sector_sum = sums->sums;
4322 sums->bytenr = ordered->start;
4323
4324 offset = 0;
4325 while (offset < sums->len) {
4326 sector_sum->bytenr += ordered->start - disk_bytenr;
4327 sector_sum++;
4328 offset += root->sectorsize;
4329 }
4330
4331 btrfs_add_ordered_sum(inode, ordered, sums);
4332 }
4333 out:
4334 btrfs_put_ordered_extent(ordered);
4335 return ret;
4336 }
4337
4338 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4339 struct btrfs_root *root, struct extent_buffer *buf,
4340 struct extent_buffer *cow)
4341 {
4342 struct reloc_control *rc;
4343 struct backref_node *node;
4344 int first_cow = 0;
4345 int level;
4346 int ret;
4347
4348 rc = root->fs_info->reloc_ctl;
4349 if (!rc)
4350 return;
4351
4352 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4353 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4354
4355 level = btrfs_header_level(buf);
4356 if (btrfs_header_generation(buf) <=
4357 btrfs_root_last_snapshot(&root->root_item))
4358 first_cow = 1;
4359
4360 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4361 rc->create_reloc_tree) {
4362 WARN_ON(!first_cow && level == 0);
4363
4364 node = rc->backref_cache.path[level];
4365 BUG_ON(node->bytenr != buf->start &&
4366 node->new_bytenr != buf->start);
4367
4368 drop_node_buffer(node);
4369 extent_buffer_get(cow);
4370 node->eb = cow;
4371 node->new_bytenr = cow->start;
4372
4373 if (!node->pending) {
4374 list_move_tail(&node->list,
4375 &rc->backref_cache.pending[level]);
4376 node->pending = 1;
4377 }
4378
4379 if (first_cow)
4380 __mark_block_processed(rc, node);
4381
4382 if (first_cow && level > 0)
4383 rc->nodes_relocated += buf->len;
4384 }
4385
4386 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4387 ret = replace_file_extents(trans, rc, root, cow);
4388 BUG_ON(ret);
4389 }
4390 }
4391
4392 /*
4393 * called before creating snapshot. it calculates metadata reservation
4394 * requried for relocating tree blocks in the snapshot
4395 */
4396 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4397 struct btrfs_pending_snapshot *pending,
4398 u64 *bytes_to_reserve)
4399 {
4400 struct btrfs_root *root;
4401 struct reloc_control *rc;
4402
4403 root = pending->root;
4404 if (!root->reloc_root)
4405 return;
4406
4407 rc = root->fs_info->reloc_ctl;
4408 if (!rc->merge_reloc_tree)
4409 return;
4410
4411 root = root->reloc_root;
4412 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4413 /*
4414 * relocation is in the stage of merging trees. the space
4415 * used by merging a reloc tree is twice the size of
4416 * relocated tree nodes in the worst case. half for cowing
4417 * the reloc tree, half for cowing the fs tree. the space
4418 * used by cowing the reloc tree will be freed after the
4419 * tree is dropped. if we create snapshot, cowing the fs
4420 * tree may use more space than it frees. so we need
4421 * reserve extra space.
4422 */
4423 *bytes_to_reserve += rc->nodes_relocated;
4424 }
4425
4426 /*
4427 * called after snapshot is created. migrate block reservation
4428 * and create reloc root for the newly created snapshot
4429 */
4430 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4431 struct btrfs_pending_snapshot *pending)
4432 {
4433 struct btrfs_root *root = pending->root;
4434 struct btrfs_root *reloc_root;
4435 struct btrfs_root *new_root;
4436 struct reloc_control *rc;
4437 int ret;
4438
4439 if (!root->reloc_root)
4440 return 0;
4441
4442 rc = root->fs_info->reloc_ctl;
4443 rc->merging_rsv_size += rc->nodes_relocated;
4444
4445 if (rc->merge_reloc_tree) {
4446 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4447 rc->block_rsv,
4448 rc->nodes_relocated);
4449 if (ret)
4450 return ret;
4451 }
4452
4453 new_root = pending->snap;
4454 reloc_root = create_reloc_root(trans, root->reloc_root,
4455 new_root->root_key.objectid);
4456 if (IS_ERR(reloc_root))
4457 return PTR_ERR(reloc_root);
4458
4459 ret = __add_reloc_root(reloc_root);
4460 BUG_ON(ret < 0);
4461 new_root->reloc_root = reloc_root;
4462
4463 if (rc->create_reloc_tree)
4464 ret = clone_backref_node(trans, rc, root, reloc_root);
4465 return ret;
4466 }
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