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Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro...
[deliverable/linux.git] / fs / btrfs / relocation.c
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97
98 struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
108 struct list_head pending[BTRFS_MAX_LEVEL];
109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
120 };
121
122 /*
123 * map address of tree root to tree
124 */
125 struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129 };
130
131 struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134 };
135
136 /*
137 * present a tree block to process
138 */
139 struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145 };
146
147 #define MAX_EXTENTS 128
148
149 struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154 };
155
156 struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
180 u64 search_start;
181 u64 extents_found;
182
183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
186 unsigned int found_file_extent:1;
187 unsigned int commit_transaction:1;
188 };
189
190 /* stages of data relocation */
191 #define MOVE_DATA_EXTENTS 0
192 #define UPDATE_DATA_PTRS 1
193
194 static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196 static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
198
199 static void mapping_tree_init(struct mapping_tree *tree)
200 {
201 tree->rb_root = RB_ROOT;
202 spin_lock_init(&tree->lock);
203 }
204
205 static void backref_cache_init(struct backref_cache *cache)
206 {
207 int i;
208 cache->rb_root = RB_ROOT;
209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214 }
215
216 static void backref_cache_cleanup(struct backref_cache *cache)
217 {
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242 }
243
244 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245 {
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257 }
258
259 static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261 {
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266 }
267
268 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269 {
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
276 }
277
278 static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
280 {
281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
285 }
286
287 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289 {
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309 }
310
311 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312 {
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327 }
328
329 /*
330 * walk up backref nodes until reach node presents tree root
331 */
332 static struct backref_node *walk_up_backref(struct backref_node *node,
333 struct backref_edge *edges[],
334 int *index)
335 {
336 struct backref_edge *edge;
337 int idx = *index;
338
339 while (!list_empty(&node->upper)) {
340 edge = list_entry(node->upper.next,
341 struct backref_edge, list[LOWER]);
342 edges[idx++] = edge;
343 node = edge->node[UPPER];
344 }
345 BUG_ON(node->detached);
346 *index = idx;
347 return node;
348 }
349
350 /*
351 * walk down backref nodes to find start of next reference path
352 */
353 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
354 int *index)
355 {
356 struct backref_edge *edge;
357 struct backref_node *lower;
358 int idx = *index;
359
360 while (idx > 0) {
361 edge = edges[idx - 1];
362 lower = edge->node[LOWER];
363 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
364 idx--;
365 continue;
366 }
367 edge = list_entry(edge->list[LOWER].next,
368 struct backref_edge, list[LOWER]);
369 edges[idx - 1] = edge;
370 *index = idx;
371 return edge->node[UPPER];
372 }
373 *index = 0;
374 return NULL;
375 }
376
377 static void unlock_node_buffer(struct backref_node *node)
378 {
379 if (node->locked) {
380 btrfs_tree_unlock(node->eb);
381 node->locked = 0;
382 }
383 }
384
385 static void drop_node_buffer(struct backref_node *node)
386 {
387 if (node->eb) {
388 unlock_node_buffer(node);
389 free_extent_buffer(node->eb);
390 node->eb = NULL;
391 }
392 }
393
394 static void drop_backref_node(struct backref_cache *tree,
395 struct backref_node *node)
396 {
397 BUG_ON(!list_empty(&node->upper));
398
399 drop_node_buffer(node);
400 list_del(&node->list);
401 list_del(&node->lower);
402 if (!RB_EMPTY_NODE(&node->rb_node))
403 rb_erase(&node->rb_node, &tree->rb_root);
404 free_backref_node(tree, node);
405 }
406
407 /*
408 * remove a backref node from the backref cache
409 */
410 static void remove_backref_node(struct backref_cache *cache,
411 struct backref_node *node)
412 {
413 struct backref_node *upper;
414 struct backref_edge *edge;
415
416 if (!node)
417 return;
418
419 BUG_ON(!node->lowest && !node->detached);
420 while (!list_empty(&node->upper)) {
421 edge = list_entry(node->upper.next, struct backref_edge,
422 list[LOWER]);
423 upper = edge->node[UPPER];
424 list_del(&edge->list[LOWER]);
425 list_del(&edge->list[UPPER]);
426 free_backref_edge(cache, edge);
427
428 if (RB_EMPTY_NODE(&upper->rb_node)) {
429 BUG_ON(!list_empty(&node->upper));
430 drop_backref_node(cache, node);
431 node = upper;
432 node->lowest = 1;
433 continue;
434 }
435 /*
436 * add the node to leaf node list if no other
437 * child block cached.
438 */
439 if (list_empty(&upper->lower)) {
440 list_add_tail(&upper->lower, &cache->leaves);
441 upper->lowest = 1;
442 }
443 }
444
445 drop_backref_node(cache, node);
446 }
447
448 static void update_backref_node(struct backref_cache *cache,
449 struct backref_node *node, u64 bytenr)
450 {
451 struct rb_node *rb_node;
452 rb_erase(&node->rb_node, &cache->rb_root);
453 node->bytenr = bytenr;
454 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
455 BUG_ON(rb_node);
456 }
457
458 /*
459 * update backref cache after a transaction commit
460 */
461 static int update_backref_cache(struct btrfs_trans_handle *trans,
462 struct backref_cache *cache)
463 {
464 struct backref_node *node;
465 int level = 0;
466
467 if (cache->last_trans == 0) {
468 cache->last_trans = trans->transid;
469 return 0;
470 }
471
472 if (cache->last_trans == trans->transid)
473 return 0;
474
475 /*
476 * detached nodes are used to avoid unnecessary backref
477 * lookup. transaction commit changes the extent tree.
478 * so the detached nodes are no longer useful.
479 */
480 while (!list_empty(&cache->detached)) {
481 node = list_entry(cache->detached.next,
482 struct backref_node, list);
483 remove_backref_node(cache, node);
484 }
485
486 while (!list_empty(&cache->changed)) {
487 node = list_entry(cache->changed.next,
488 struct backref_node, list);
489 list_del_init(&node->list);
490 BUG_ON(node->pending);
491 update_backref_node(cache, node, node->new_bytenr);
492 }
493
494 /*
495 * some nodes can be left in the pending list if there were
496 * errors during processing the pending nodes.
497 */
498 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
499 list_for_each_entry(node, &cache->pending[level], list) {
500 BUG_ON(!node->pending);
501 if (node->bytenr == node->new_bytenr)
502 continue;
503 update_backref_node(cache, node, node->new_bytenr);
504 }
505 }
506
507 cache->last_trans = 0;
508 return 1;
509 }
510
511
512 static int should_ignore_root(struct btrfs_root *root)
513 {
514 struct btrfs_root *reloc_root;
515
516 if (!root->ref_cows)
517 return 0;
518
519 reloc_root = root->reloc_root;
520 if (!reloc_root)
521 return 0;
522
523 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
524 root->fs_info->running_transaction->transid - 1)
525 return 0;
526 /*
527 * if there is reloc tree and it was created in previous
528 * transaction backref lookup can find the reloc tree,
529 * so backref node for the fs tree root is useless for
530 * relocation.
531 */
532 return 1;
533 }
534 /*
535 * find reloc tree by address of tree root
536 */
537 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
538 u64 bytenr)
539 {
540 struct rb_node *rb_node;
541 struct mapping_node *node;
542 struct btrfs_root *root = NULL;
543
544 spin_lock(&rc->reloc_root_tree.lock);
545 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
546 if (rb_node) {
547 node = rb_entry(rb_node, struct mapping_node, rb_node);
548 root = (struct btrfs_root *)node->data;
549 }
550 spin_unlock(&rc->reloc_root_tree.lock);
551 return root;
552 }
553
554 static int is_cowonly_root(u64 root_objectid)
555 {
556 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
557 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
558 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
559 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
560 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
561 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
562 return 1;
563 return 0;
564 }
565
566 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
567 u64 root_objectid)
568 {
569 struct btrfs_key key;
570
571 key.objectid = root_objectid;
572 key.type = BTRFS_ROOT_ITEM_KEY;
573 if (is_cowonly_root(root_objectid))
574 key.offset = 0;
575 else
576 key.offset = (u64)-1;
577
578 return btrfs_read_fs_root_no_name(fs_info, &key);
579 }
580
581 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
582 static noinline_for_stack
583 struct btrfs_root *find_tree_root(struct reloc_control *rc,
584 struct extent_buffer *leaf,
585 struct btrfs_extent_ref_v0 *ref0)
586 {
587 struct btrfs_root *root;
588 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
589 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
590
591 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
592
593 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
594 BUG_ON(IS_ERR(root));
595
596 if (root->ref_cows &&
597 generation != btrfs_root_generation(&root->root_item))
598 return NULL;
599
600 return root;
601 }
602 #endif
603
604 static noinline_for_stack
605 int find_inline_backref(struct extent_buffer *leaf, int slot,
606 unsigned long *ptr, unsigned long *end)
607 {
608 struct btrfs_extent_item *ei;
609 struct btrfs_tree_block_info *bi;
610 u32 item_size;
611
612 item_size = btrfs_item_size_nr(leaf, slot);
613 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
614 if (item_size < sizeof(*ei)) {
615 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
616 return 1;
617 }
618 #endif
619 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
620 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
621 BTRFS_EXTENT_FLAG_TREE_BLOCK));
622
623 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
624 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
625 return 1;
626 }
627
628 bi = (struct btrfs_tree_block_info *)(ei + 1);
629 *ptr = (unsigned long)(bi + 1);
630 *end = (unsigned long)ei + item_size;
631 return 0;
632 }
633
634 /*
635 * build backref tree for a given tree block. root of the backref tree
636 * corresponds the tree block, leaves of the backref tree correspond
637 * roots of b-trees that reference the tree block.
638 *
639 * the basic idea of this function is check backrefs of a given block
640 * to find upper level blocks that refernece the block, and then check
641 * bakcrefs of these upper level blocks recursively. the recursion stop
642 * when tree root is reached or backrefs for the block is cached.
643 *
644 * NOTE: if we find backrefs for a block are cached, we know backrefs
645 * for all upper level blocks that directly/indirectly reference the
646 * block are also cached.
647 */
648 static noinline_for_stack
649 struct backref_node *build_backref_tree(struct reloc_control *rc,
650 struct btrfs_key *node_key,
651 int level, u64 bytenr)
652 {
653 struct backref_cache *cache = &rc->backref_cache;
654 struct btrfs_path *path1;
655 struct btrfs_path *path2;
656 struct extent_buffer *eb;
657 struct btrfs_root *root;
658 struct backref_node *cur;
659 struct backref_node *upper;
660 struct backref_node *lower;
661 struct backref_node *node = NULL;
662 struct backref_node *exist = NULL;
663 struct backref_edge *edge;
664 struct rb_node *rb_node;
665 struct btrfs_key key;
666 unsigned long end;
667 unsigned long ptr;
668 LIST_HEAD(list);
669 LIST_HEAD(useless);
670 int cowonly;
671 int ret;
672 int err = 0;
673
674 path1 = btrfs_alloc_path();
675 path2 = btrfs_alloc_path();
676 if (!path1 || !path2) {
677 err = -ENOMEM;
678 goto out;
679 }
680 path1->reada = 1;
681 path2->reada = 2;
682
683 node = alloc_backref_node(cache);
684 if (!node) {
685 err = -ENOMEM;
686 goto out;
687 }
688
689 node->bytenr = bytenr;
690 node->level = level;
691 node->lowest = 1;
692 cur = node;
693 again:
694 end = 0;
695 ptr = 0;
696 key.objectid = cur->bytenr;
697 key.type = BTRFS_EXTENT_ITEM_KEY;
698 key.offset = (u64)-1;
699
700 path1->search_commit_root = 1;
701 path1->skip_locking = 1;
702 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
703 0, 0);
704 if (ret < 0) {
705 err = ret;
706 goto out;
707 }
708 BUG_ON(!ret || !path1->slots[0]);
709
710 path1->slots[0]--;
711
712 WARN_ON(cur->checked);
713 if (!list_empty(&cur->upper)) {
714 /*
715 * the backref was added previously when processing
716 * backref of type BTRFS_TREE_BLOCK_REF_KEY
717 */
718 BUG_ON(!list_is_singular(&cur->upper));
719 edge = list_entry(cur->upper.next, struct backref_edge,
720 list[LOWER]);
721 BUG_ON(!list_empty(&edge->list[UPPER]));
722 exist = edge->node[UPPER];
723 /*
724 * add the upper level block to pending list if we need
725 * check its backrefs
726 */
727 if (!exist->checked)
728 list_add_tail(&edge->list[UPPER], &list);
729 } else {
730 exist = NULL;
731 }
732
733 while (1) {
734 cond_resched();
735 eb = path1->nodes[0];
736
737 if (ptr >= end) {
738 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
739 ret = btrfs_next_leaf(rc->extent_root, path1);
740 if (ret < 0) {
741 err = ret;
742 goto out;
743 }
744 if (ret > 0)
745 break;
746 eb = path1->nodes[0];
747 }
748
749 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
750 if (key.objectid != cur->bytenr) {
751 WARN_ON(exist);
752 break;
753 }
754
755 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
756 ret = find_inline_backref(eb, path1->slots[0],
757 &ptr, &end);
758 if (ret)
759 goto next;
760 }
761 }
762
763 if (ptr < end) {
764 /* update key for inline back ref */
765 struct btrfs_extent_inline_ref *iref;
766 iref = (struct btrfs_extent_inline_ref *)ptr;
767 key.type = btrfs_extent_inline_ref_type(eb, iref);
768 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
769 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
770 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
771 }
772
773 if (exist &&
774 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
775 exist->owner == key.offset) ||
776 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
777 exist->bytenr == key.offset))) {
778 exist = NULL;
779 goto next;
780 }
781
782 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
783 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
784 key.type == BTRFS_EXTENT_REF_V0_KEY) {
785 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
786 struct btrfs_extent_ref_v0 *ref0;
787 ref0 = btrfs_item_ptr(eb, path1->slots[0],
788 struct btrfs_extent_ref_v0);
789 if (key.objectid == key.offset) {
790 root = find_tree_root(rc, eb, ref0);
791 if (root && !should_ignore_root(root))
792 cur->root = root;
793 else
794 list_add(&cur->list, &useless);
795 break;
796 }
797 if (is_cowonly_root(btrfs_ref_root_v0(eb,
798 ref0)))
799 cur->cowonly = 1;
800 }
801 #else
802 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
803 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
804 #endif
805 if (key.objectid == key.offset) {
806 /*
807 * only root blocks of reloc trees use
808 * backref of this type.
809 */
810 root = find_reloc_root(rc, cur->bytenr);
811 BUG_ON(!root);
812 cur->root = root;
813 break;
814 }
815
816 edge = alloc_backref_edge(cache);
817 if (!edge) {
818 err = -ENOMEM;
819 goto out;
820 }
821 rb_node = tree_search(&cache->rb_root, key.offset);
822 if (!rb_node) {
823 upper = alloc_backref_node(cache);
824 if (!upper) {
825 free_backref_edge(cache, edge);
826 err = -ENOMEM;
827 goto out;
828 }
829 upper->bytenr = key.offset;
830 upper->level = cur->level + 1;
831 /*
832 * backrefs for the upper level block isn't
833 * cached, add the block to pending list
834 */
835 list_add_tail(&edge->list[UPPER], &list);
836 } else {
837 upper = rb_entry(rb_node, struct backref_node,
838 rb_node);
839 BUG_ON(!upper->checked);
840 INIT_LIST_HEAD(&edge->list[UPPER]);
841 }
842 list_add_tail(&edge->list[LOWER], &cur->upper);
843 edge->node[LOWER] = cur;
844 edge->node[UPPER] = upper;
845
846 goto next;
847 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
848 goto next;
849 }
850
851 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
852 root = read_fs_root(rc->extent_root->fs_info, key.offset);
853 if (IS_ERR(root)) {
854 err = PTR_ERR(root);
855 goto out;
856 }
857
858 if (!root->ref_cows)
859 cur->cowonly = 1;
860
861 if (btrfs_root_level(&root->root_item) == cur->level) {
862 /* tree root */
863 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
864 cur->bytenr);
865 if (should_ignore_root(root))
866 list_add(&cur->list, &useless);
867 else
868 cur->root = root;
869 break;
870 }
871
872 level = cur->level + 1;
873
874 /*
875 * searching the tree to find upper level blocks
876 * reference the block.
877 */
878 path2->search_commit_root = 1;
879 path2->skip_locking = 1;
880 path2->lowest_level = level;
881 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
882 path2->lowest_level = 0;
883 if (ret < 0) {
884 err = ret;
885 goto out;
886 }
887 if (ret > 0 && path2->slots[level] > 0)
888 path2->slots[level]--;
889
890 eb = path2->nodes[level];
891 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
892 cur->bytenr);
893
894 lower = cur;
895 for (; level < BTRFS_MAX_LEVEL; level++) {
896 if (!path2->nodes[level]) {
897 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
898 lower->bytenr);
899 if (should_ignore_root(root))
900 list_add(&lower->list, &useless);
901 else
902 lower->root = root;
903 break;
904 }
905
906 edge = alloc_backref_edge(cache);
907 if (!edge) {
908 err = -ENOMEM;
909 goto out;
910 }
911
912 eb = path2->nodes[level];
913 rb_node = tree_search(&cache->rb_root, eb->start);
914 if (!rb_node) {
915 upper = alloc_backref_node(cache);
916 if (!upper) {
917 free_backref_edge(cache, edge);
918 err = -ENOMEM;
919 goto out;
920 }
921 upper->bytenr = eb->start;
922 upper->owner = btrfs_header_owner(eb);
923 upper->level = lower->level + 1;
924 if (!root->ref_cows)
925 upper->cowonly = 1;
926
927 /*
928 * if we know the block isn't shared
929 * we can void checking its backrefs.
930 */
931 if (btrfs_block_can_be_shared(root, eb))
932 upper->checked = 0;
933 else
934 upper->checked = 1;
935
936 /*
937 * add the block to pending list if we
938 * need check its backrefs. only block
939 * at 'cur->level + 1' is added to the
940 * tail of pending list. this guarantees
941 * we check backrefs from lower level
942 * blocks to upper level blocks.
943 */
944 if (!upper->checked &&
945 level == cur->level + 1) {
946 list_add_tail(&edge->list[UPPER],
947 &list);
948 } else
949 INIT_LIST_HEAD(&edge->list[UPPER]);
950 } else {
951 upper = rb_entry(rb_node, struct backref_node,
952 rb_node);
953 BUG_ON(!upper->checked);
954 INIT_LIST_HEAD(&edge->list[UPPER]);
955 if (!upper->owner)
956 upper->owner = btrfs_header_owner(eb);
957 }
958 list_add_tail(&edge->list[LOWER], &lower->upper);
959 edge->node[LOWER] = lower;
960 edge->node[UPPER] = upper;
961
962 if (rb_node)
963 break;
964 lower = upper;
965 upper = NULL;
966 }
967 btrfs_release_path(path2);
968 next:
969 if (ptr < end) {
970 ptr += btrfs_extent_inline_ref_size(key.type);
971 if (ptr >= end) {
972 WARN_ON(ptr > end);
973 ptr = 0;
974 end = 0;
975 }
976 }
977 if (ptr >= end)
978 path1->slots[0]++;
979 }
980 btrfs_release_path(path1);
981
982 cur->checked = 1;
983 WARN_ON(exist);
984
985 /* the pending list isn't empty, take the first block to process */
986 if (!list_empty(&list)) {
987 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
988 list_del_init(&edge->list[UPPER]);
989 cur = edge->node[UPPER];
990 goto again;
991 }
992
993 /*
994 * everything goes well, connect backref nodes and insert backref nodes
995 * into the cache.
996 */
997 BUG_ON(!node->checked);
998 cowonly = node->cowonly;
999 if (!cowonly) {
1000 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1001 &node->rb_node);
1002 BUG_ON(rb_node);
1003 list_add_tail(&node->lower, &cache->leaves);
1004 }
1005
1006 list_for_each_entry(edge, &node->upper, list[LOWER])
1007 list_add_tail(&edge->list[UPPER], &list);
1008
1009 while (!list_empty(&list)) {
1010 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1011 list_del_init(&edge->list[UPPER]);
1012 upper = edge->node[UPPER];
1013 if (upper->detached) {
1014 list_del(&edge->list[LOWER]);
1015 lower = edge->node[LOWER];
1016 free_backref_edge(cache, edge);
1017 if (list_empty(&lower->upper))
1018 list_add(&lower->list, &useless);
1019 continue;
1020 }
1021
1022 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1023 if (upper->lowest) {
1024 list_del_init(&upper->lower);
1025 upper->lowest = 0;
1026 }
1027
1028 list_add_tail(&edge->list[UPPER], &upper->lower);
1029 continue;
1030 }
1031
1032 BUG_ON(!upper->checked);
1033 BUG_ON(cowonly != upper->cowonly);
1034 if (!cowonly) {
1035 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1036 &upper->rb_node);
1037 BUG_ON(rb_node);
1038 }
1039
1040 list_add_tail(&edge->list[UPPER], &upper->lower);
1041
1042 list_for_each_entry(edge, &upper->upper, list[LOWER])
1043 list_add_tail(&edge->list[UPPER], &list);
1044 }
1045 /*
1046 * process useless backref nodes. backref nodes for tree leaves
1047 * are deleted from the cache. backref nodes for upper level
1048 * tree blocks are left in the cache to avoid unnecessary backref
1049 * lookup.
1050 */
1051 while (!list_empty(&useless)) {
1052 upper = list_entry(useless.next, struct backref_node, list);
1053 list_del_init(&upper->list);
1054 BUG_ON(!list_empty(&upper->upper));
1055 if (upper == node)
1056 node = NULL;
1057 if (upper->lowest) {
1058 list_del_init(&upper->lower);
1059 upper->lowest = 0;
1060 }
1061 while (!list_empty(&upper->lower)) {
1062 edge = list_entry(upper->lower.next,
1063 struct backref_edge, list[UPPER]);
1064 list_del(&edge->list[UPPER]);
1065 list_del(&edge->list[LOWER]);
1066 lower = edge->node[LOWER];
1067 free_backref_edge(cache, edge);
1068
1069 if (list_empty(&lower->upper))
1070 list_add(&lower->list, &useless);
1071 }
1072 __mark_block_processed(rc, upper);
1073 if (upper->level > 0) {
1074 list_add(&upper->list, &cache->detached);
1075 upper->detached = 1;
1076 } else {
1077 rb_erase(&upper->rb_node, &cache->rb_root);
1078 free_backref_node(cache, upper);
1079 }
1080 }
1081 out:
1082 btrfs_free_path(path1);
1083 btrfs_free_path(path2);
1084 if (err) {
1085 while (!list_empty(&useless)) {
1086 lower = list_entry(useless.next,
1087 struct backref_node, upper);
1088 list_del_init(&lower->upper);
1089 }
1090 upper = node;
1091 INIT_LIST_HEAD(&list);
1092 while (upper) {
1093 if (RB_EMPTY_NODE(&upper->rb_node)) {
1094 list_splice_tail(&upper->upper, &list);
1095 free_backref_node(cache, upper);
1096 }
1097
1098 if (list_empty(&list))
1099 break;
1100
1101 edge = list_entry(list.next, struct backref_edge,
1102 list[LOWER]);
1103 list_del(&edge->list[LOWER]);
1104 upper = edge->node[UPPER];
1105 free_backref_edge(cache, edge);
1106 }
1107 return ERR_PTR(err);
1108 }
1109 BUG_ON(node && node->detached);
1110 return node;
1111 }
1112
1113 /*
1114 * helper to add backref node for the newly created snapshot.
1115 * the backref node is created by cloning backref node that
1116 * corresponds to root of source tree
1117 */
1118 static int clone_backref_node(struct btrfs_trans_handle *trans,
1119 struct reloc_control *rc,
1120 struct btrfs_root *src,
1121 struct btrfs_root *dest)
1122 {
1123 struct btrfs_root *reloc_root = src->reloc_root;
1124 struct backref_cache *cache = &rc->backref_cache;
1125 struct backref_node *node = NULL;
1126 struct backref_node *new_node;
1127 struct backref_edge *edge;
1128 struct backref_edge *new_edge;
1129 struct rb_node *rb_node;
1130
1131 if (cache->last_trans > 0)
1132 update_backref_cache(trans, cache);
1133
1134 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1135 if (rb_node) {
1136 node = rb_entry(rb_node, struct backref_node, rb_node);
1137 if (node->detached)
1138 node = NULL;
1139 else
1140 BUG_ON(node->new_bytenr != reloc_root->node->start);
1141 }
1142
1143 if (!node) {
1144 rb_node = tree_search(&cache->rb_root,
1145 reloc_root->commit_root->start);
1146 if (rb_node) {
1147 node = rb_entry(rb_node, struct backref_node,
1148 rb_node);
1149 BUG_ON(node->detached);
1150 }
1151 }
1152
1153 if (!node)
1154 return 0;
1155
1156 new_node = alloc_backref_node(cache);
1157 if (!new_node)
1158 return -ENOMEM;
1159
1160 new_node->bytenr = dest->node->start;
1161 new_node->level = node->level;
1162 new_node->lowest = node->lowest;
1163 new_node->checked = 1;
1164 new_node->root = dest;
1165
1166 if (!node->lowest) {
1167 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1168 new_edge = alloc_backref_edge(cache);
1169 if (!new_edge)
1170 goto fail;
1171
1172 new_edge->node[UPPER] = new_node;
1173 new_edge->node[LOWER] = edge->node[LOWER];
1174 list_add_tail(&new_edge->list[UPPER],
1175 &new_node->lower);
1176 }
1177 }
1178
1179 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1180 &new_node->rb_node);
1181 BUG_ON(rb_node);
1182
1183 if (!new_node->lowest) {
1184 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1185 list_add_tail(&new_edge->list[LOWER],
1186 &new_edge->node[LOWER]->upper);
1187 }
1188 }
1189 return 0;
1190 fail:
1191 while (!list_empty(&new_node->lower)) {
1192 new_edge = list_entry(new_node->lower.next,
1193 struct backref_edge, list[UPPER]);
1194 list_del(&new_edge->list[UPPER]);
1195 free_backref_edge(cache, new_edge);
1196 }
1197 free_backref_node(cache, new_node);
1198 return -ENOMEM;
1199 }
1200
1201 /*
1202 * helper to add 'address of tree root -> reloc tree' mapping
1203 */
1204 static int __add_reloc_root(struct btrfs_root *root)
1205 {
1206 struct rb_node *rb_node;
1207 struct mapping_node *node;
1208 struct reloc_control *rc = root->fs_info->reloc_ctl;
1209
1210 node = kmalloc(sizeof(*node), GFP_NOFS);
1211 BUG_ON(!node);
1212
1213 node->bytenr = root->node->start;
1214 node->data = root;
1215
1216 spin_lock(&rc->reloc_root_tree.lock);
1217 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1218 node->bytenr, &node->rb_node);
1219 spin_unlock(&rc->reloc_root_tree.lock);
1220 BUG_ON(rb_node);
1221
1222 list_add_tail(&root->root_list, &rc->reloc_roots);
1223 return 0;
1224 }
1225
1226 /*
1227 * helper to update/delete the 'address of tree root -> reloc tree'
1228 * mapping
1229 */
1230 static int __update_reloc_root(struct btrfs_root *root, int del)
1231 {
1232 struct rb_node *rb_node;
1233 struct mapping_node *node = NULL;
1234 struct reloc_control *rc = root->fs_info->reloc_ctl;
1235
1236 spin_lock(&rc->reloc_root_tree.lock);
1237 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1238 root->commit_root->start);
1239 if (rb_node) {
1240 node = rb_entry(rb_node, struct mapping_node, rb_node);
1241 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1242 }
1243 spin_unlock(&rc->reloc_root_tree.lock);
1244
1245 BUG_ON((struct btrfs_root *)node->data != root);
1246
1247 if (!del) {
1248 spin_lock(&rc->reloc_root_tree.lock);
1249 node->bytenr = root->node->start;
1250 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1251 node->bytenr, &node->rb_node);
1252 spin_unlock(&rc->reloc_root_tree.lock);
1253 BUG_ON(rb_node);
1254 } else {
1255 list_del_init(&root->root_list);
1256 kfree(node);
1257 }
1258 return 0;
1259 }
1260
1261 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1262 struct btrfs_root *root, u64 objectid)
1263 {
1264 struct btrfs_root *reloc_root;
1265 struct extent_buffer *eb;
1266 struct btrfs_root_item *root_item;
1267 struct btrfs_key root_key;
1268 int ret;
1269
1270 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1271 BUG_ON(!root_item);
1272
1273 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1274 root_key.type = BTRFS_ROOT_ITEM_KEY;
1275 root_key.offset = objectid;
1276
1277 if (root->root_key.objectid == objectid) {
1278 /* called by btrfs_init_reloc_root */
1279 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1280 BTRFS_TREE_RELOC_OBJECTID);
1281 BUG_ON(ret);
1282
1283 btrfs_set_root_last_snapshot(&root->root_item,
1284 trans->transid - 1);
1285 } else {
1286 /*
1287 * called by btrfs_reloc_post_snapshot_hook.
1288 * the source tree is a reloc tree, all tree blocks
1289 * modified after it was created have RELOC flag
1290 * set in their headers. so it's OK to not update
1291 * the 'last_snapshot'.
1292 */
1293 ret = btrfs_copy_root(trans, root, root->node, &eb,
1294 BTRFS_TREE_RELOC_OBJECTID);
1295 BUG_ON(ret);
1296 }
1297
1298 memcpy(root_item, &root->root_item, sizeof(*root_item));
1299 btrfs_set_root_bytenr(root_item, eb->start);
1300 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1301 btrfs_set_root_generation(root_item, trans->transid);
1302
1303 if (root->root_key.objectid == objectid) {
1304 btrfs_set_root_refs(root_item, 0);
1305 memset(&root_item->drop_progress, 0,
1306 sizeof(struct btrfs_disk_key));
1307 root_item->drop_level = 0;
1308 }
1309
1310 btrfs_tree_unlock(eb);
1311 free_extent_buffer(eb);
1312
1313 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1314 &root_key, root_item);
1315 BUG_ON(ret);
1316 kfree(root_item);
1317
1318 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1319 &root_key);
1320 BUG_ON(IS_ERR(reloc_root));
1321 reloc_root->last_trans = trans->transid;
1322 return reloc_root;
1323 }
1324
1325 /*
1326 * create reloc tree for a given fs tree. reloc tree is just a
1327 * snapshot of the fs tree with special root objectid.
1328 */
1329 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1330 struct btrfs_root *root)
1331 {
1332 struct btrfs_root *reloc_root;
1333 struct reloc_control *rc = root->fs_info->reloc_ctl;
1334 int clear_rsv = 0;
1335
1336 if (root->reloc_root) {
1337 reloc_root = root->reloc_root;
1338 reloc_root->last_trans = trans->transid;
1339 return 0;
1340 }
1341
1342 if (!rc || !rc->create_reloc_tree ||
1343 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1344 return 0;
1345
1346 if (!trans->block_rsv) {
1347 trans->block_rsv = rc->block_rsv;
1348 clear_rsv = 1;
1349 }
1350 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1351 if (clear_rsv)
1352 trans->block_rsv = NULL;
1353
1354 __add_reloc_root(reloc_root);
1355 root->reloc_root = reloc_root;
1356 return 0;
1357 }
1358
1359 /*
1360 * update root item of reloc tree
1361 */
1362 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1363 struct btrfs_root *root)
1364 {
1365 struct btrfs_root *reloc_root;
1366 struct btrfs_root_item *root_item;
1367 int del = 0;
1368 int ret;
1369
1370 if (!root->reloc_root)
1371 return 0;
1372
1373 reloc_root = root->reloc_root;
1374 root_item = &reloc_root->root_item;
1375
1376 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1377 btrfs_root_refs(root_item) == 0) {
1378 root->reloc_root = NULL;
1379 del = 1;
1380 }
1381
1382 __update_reloc_root(reloc_root, del);
1383
1384 if (reloc_root->commit_root != reloc_root->node) {
1385 btrfs_set_root_node(root_item, reloc_root->node);
1386 free_extent_buffer(reloc_root->commit_root);
1387 reloc_root->commit_root = btrfs_root_node(reloc_root);
1388 }
1389
1390 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1391 &reloc_root->root_key, root_item);
1392 BUG_ON(ret);
1393 return 0;
1394 }
1395
1396 /*
1397 * helper to find first cached inode with inode number >= objectid
1398 * in a subvolume
1399 */
1400 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1401 {
1402 struct rb_node *node;
1403 struct rb_node *prev;
1404 struct btrfs_inode *entry;
1405 struct inode *inode;
1406
1407 spin_lock(&root->inode_lock);
1408 again:
1409 node = root->inode_tree.rb_node;
1410 prev = NULL;
1411 while (node) {
1412 prev = node;
1413 entry = rb_entry(node, struct btrfs_inode, rb_node);
1414
1415 if (objectid < btrfs_ino(&entry->vfs_inode))
1416 node = node->rb_left;
1417 else if (objectid > btrfs_ino(&entry->vfs_inode))
1418 node = node->rb_right;
1419 else
1420 break;
1421 }
1422 if (!node) {
1423 while (prev) {
1424 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1425 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1426 node = prev;
1427 break;
1428 }
1429 prev = rb_next(prev);
1430 }
1431 }
1432 while (node) {
1433 entry = rb_entry(node, struct btrfs_inode, rb_node);
1434 inode = igrab(&entry->vfs_inode);
1435 if (inode) {
1436 spin_unlock(&root->inode_lock);
1437 return inode;
1438 }
1439
1440 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1441 if (cond_resched_lock(&root->inode_lock))
1442 goto again;
1443
1444 node = rb_next(node);
1445 }
1446 spin_unlock(&root->inode_lock);
1447 return NULL;
1448 }
1449
1450 static int in_block_group(u64 bytenr,
1451 struct btrfs_block_group_cache *block_group)
1452 {
1453 if (bytenr >= block_group->key.objectid &&
1454 bytenr < block_group->key.objectid + block_group->key.offset)
1455 return 1;
1456 return 0;
1457 }
1458
1459 /*
1460 * get new location of data
1461 */
1462 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1463 u64 bytenr, u64 num_bytes)
1464 {
1465 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1466 struct btrfs_path *path;
1467 struct btrfs_file_extent_item *fi;
1468 struct extent_buffer *leaf;
1469 int ret;
1470
1471 path = btrfs_alloc_path();
1472 if (!path)
1473 return -ENOMEM;
1474
1475 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1476 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1477 bytenr, 0);
1478 if (ret < 0)
1479 goto out;
1480 if (ret > 0) {
1481 ret = -ENOENT;
1482 goto out;
1483 }
1484
1485 leaf = path->nodes[0];
1486 fi = btrfs_item_ptr(leaf, path->slots[0],
1487 struct btrfs_file_extent_item);
1488
1489 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1490 btrfs_file_extent_compression(leaf, fi) ||
1491 btrfs_file_extent_encryption(leaf, fi) ||
1492 btrfs_file_extent_other_encoding(leaf, fi));
1493
1494 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1495 ret = 1;
1496 goto out;
1497 }
1498
1499 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1500 ret = 0;
1501 out:
1502 btrfs_free_path(path);
1503 return ret;
1504 }
1505
1506 /*
1507 * update file extent items in the tree leaf to point to
1508 * the new locations.
1509 */
1510 static noinline_for_stack
1511 int replace_file_extents(struct btrfs_trans_handle *trans,
1512 struct reloc_control *rc,
1513 struct btrfs_root *root,
1514 struct extent_buffer *leaf)
1515 {
1516 struct btrfs_key key;
1517 struct btrfs_file_extent_item *fi;
1518 struct inode *inode = NULL;
1519 u64 parent;
1520 u64 bytenr;
1521 u64 new_bytenr = 0;
1522 u64 num_bytes;
1523 u64 end;
1524 u32 nritems;
1525 u32 i;
1526 int ret;
1527 int first = 1;
1528 int dirty = 0;
1529
1530 if (rc->stage != UPDATE_DATA_PTRS)
1531 return 0;
1532
1533 /* reloc trees always use full backref */
1534 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1535 parent = leaf->start;
1536 else
1537 parent = 0;
1538
1539 nritems = btrfs_header_nritems(leaf);
1540 for (i = 0; i < nritems; i++) {
1541 cond_resched();
1542 btrfs_item_key_to_cpu(leaf, &key, i);
1543 if (key.type != BTRFS_EXTENT_DATA_KEY)
1544 continue;
1545 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1546 if (btrfs_file_extent_type(leaf, fi) ==
1547 BTRFS_FILE_EXTENT_INLINE)
1548 continue;
1549 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1550 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1551 if (bytenr == 0)
1552 continue;
1553 if (!in_block_group(bytenr, rc->block_group))
1554 continue;
1555
1556 /*
1557 * if we are modifying block in fs tree, wait for readpage
1558 * to complete and drop the extent cache
1559 */
1560 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1561 if (first) {
1562 inode = find_next_inode(root, key.objectid);
1563 first = 0;
1564 } else if (inode && btrfs_ino(inode) < key.objectid) {
1565 btrfs_add_delayed_iput(inode);
1566 inode = find_next_inode(root, key.objectid);
1567 }
1568 if (inode && btrfs_ino(inode) == key.objectid) {
1569 end = key.offset +
1570 btrfs_file_extent_num_bytes(leaf, fi);
1571 WARN_ON(!IS_ALIGNED(key.offset,
1572 root->sectorsize));
1573 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1574 end--;
1575 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1576 key.offset, end,
1577 GFP_NOFS);
1578 if (!ret)
1579 continue;
1580
1581 btrfs_drop_extent_cache(inode, key.offset, end,
1582 1);
1583 unlock_extent(&BTRFS_I(inode)->io_tree,
1584 key.offset, end, GFP_NOFS);
1585 }
1586 }
1587
1588 ret = get_new_location(rc->data_inode, &new_bytenr,
1589 bytenr, num_bytes);
1590 if (ret > 0) {
1591 WARN_ON(1);
1592 continue;
1593 }
1594 BUG_ON(ret < 0);
1595
1596 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1597 dirty = 1;
1598
1599 key.offset -= btrfs_file_extent_offset(leaf, fi);
1600 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1601 num_bytes, parent,
1602 btrfs_header_owner(leaf),
1603 key.objectid, key.offset);
1604 BUG_ON(ret);
1605
1606 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1607 parent, btrfs_header_owner(leaf),
1608 key.objectid, key.offset);
1609 BUG_ON(ret);
1610 }
1611 if (dirty)
1612 btrfs_mark_buffer_dirty(leaf);
1613 if (inode)
1614 btrfs_add_delayed_iput(inode);
1615 return 0;
1616 }
1617
1618 static noinline_for_stack
1619 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1620 struct btrfs_path *path, int level)
1621 {
1622 struct btrfs_disk_key key1;
1623 struct btrfs_disk_key key2;
1624 btrfs_node_key(eb, &key1, slot);
1625 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1626 return memcmp(&key1, &key2, sizeof(key1));
1627 }
1628
1629 /*
1630 * try to replace tree blocks in fs tree with the new blocks
1631 * in reloc tree. tree blocks haven't been modified since the
1632 * reloc tree was create can be replaced.
1633 *
1634 * if a block was replaced, level of the block + 1 is returned.
1635 * if no block got replaced, 0 is returned. if there are other
1636 * errors, a negative error number is returned.
1637 */
1638 static noinline_for_stack
1639 int replace_path(struct btrfs_trans_handle *trans,
1640 struct btrfs_root *dest, struct btrfs_root *src,
1641 struct btrfs_path *path, struct btrfs_key *next_key,
1642 int lowest_level, int max_level)
1643 {
1644 struct extent_buffer *eb;
1645 struct extent_buffer *parent;
1646 struct btrfs_key key;
1647 u64 old_bytenr;
1648 u64 new_bytenr;
1649 u64 old_ptr_gen;
1650 u64 new_ptr_gen;
1651 u64 last_snapshot;
1652 u32 blocksize;
1653 int cow = 0;
1654 int level;
1655 int ret;
1656 int slot;
1657
1658 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1659 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1660
1661 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1662 again:
1663 slot = path->slots[lowest_level];
1664 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1665
1666 eb = btrfs_lock_root_node(dest);
1667 btrfs_set_lock_blocking(eb);
1668 level = btrfs_header_level(eb);
1669
1670 if (level < lowest_level) {
1671 btrfs_tree_unlock(eb);
1672 free_extent_buffer(eb);
1673 return 0;
1674 }
1675
1676 if (cow) {
1677 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1678 BUG_ON(ret);
1679 }
1680 btrfs_set_lock_blocking(eb);
1681
1682 if (next_key) {
1683 next_key->objectid = (u64)-1;
1684 next_key->type = (u8)-1;
1685 next_key->offset = (u64)-1;
1686 }
1687
1688 parent = eb;
1689 while (1) {
1690 level = btrfs_header_level(parent);
1691 BUG_ON(level < lowest_level);
1692
1693 ret = btrfs_bin_search(parent, &key, level, &slot);
1694 if (ret && slot > 0)
1695 slot--;
1696
1697 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1698 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1699
1700 old_bytenr = btrfs_node_blockptr(parent, slot);
1701 blocksize = btrfs_level_size(dest, level - 1);
1702 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1703
1704 if (level <= max_level) {
1705 eb = path->nodes[level];
1706 new_bytenr = btrfs_node_blockptr(eb,
1707 path->slots[level]);
1708 new_ptr_gen = btrfs_node_ptr_generation(eb,
1709 path->slots[level]);
1710 } else {
1711 new_bytenr = 0;
1712 new_ptr_gen = 0;
1713 }
1714
1715 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1716 WARN_ON(1);
1717 ret = level;
1718 break;
1719 }
1720
1721 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1722 memcmp_node_keys(parent, slot, path, level)) {
1723 if (level <= lowest_level) {
1724 ret = 0;
1725 break;
1726 }
1727
1728 eb = read_tree_block(dest, old_bytenr, blocksize,
1729 old_ptr_gen);
1730 BUG_ON(!eb);
1731 btrfs_tree_lock(eb);
1732 if (cow) {
1733 ret = btrfs_cow_block(trans, dest, eb, parent,
1734 slot, &eb);
1735 BUG_ON(ret);
1736 }
1737 btrfs_set_lock_blocking(eb);
1738
1739 btrfs_tree_unlock(parent);
1740 free_extent_buffer(parent);
1741
1742 parent = eb;
1743 continue;
1744 }
1745
1746 if (!cow) {
1747 btrfs_tree_unlock(parent);
1748 free_extent_buffer(parent);
1749 cow = 1;
1750 goto again;
1751 }
1752
1753 btrfs_node_key_to_cpu(path->nodes[level], &key,
1754 path->slots[level]);
1755 btrfs_release_path(path);
1756
1757 path->lowest_level = level;
1758 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1759 path->lowest_level = 0;
1760 BUG_ON(ret);
1761
1762 /*
1763 * swap blocks in fs tree and reloc tree.
1764 */
1765 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1766 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1767 btrfs_mark_buffer_dirty(parent);
1768
1769 btrfs_set_node_blockptr(path->nodes[level],
1770 path->slots[level], old_bytenr);
1771 btrfs_set_node_ptr_generation(path->nodes[level],
1772 path->slots[level], old_ptr_gen);
1773 btrfs_mark_buffer_dirty(path->nodes[level]);
1774
1775 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1776 path->nodes[level]->start,
1777 src->root_key.objectid, level - 1, 0);
1778 BUG_ON(ret);
1779 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1780 0, dest->root_key.objectid, level - 1,
1781 0);
1782 BUG_ON(ret);
1783
1784 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1785 path->nodes[level]->start,
1786 src->root_key.objectid, level - 1, 0);
1787 BUG_ON(ret);
1788
1789 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1790 0, dest->root_key.objectid, level - 1,
1791 0);
1792 BUG_ON(ret);
1793
1794 btrfs_unlock_up_safe(path, 0);
1795
1796 ret = level;
1797 break;
1798 }
1799 btrfs_tree_unlock(parent);
1800 free_extent_buffer(parent);
1801 return ret;
1802 }
1803
1804 /*
1805 * helper to find next relocated block in reloc tree
1806 */
1807 static noinline_for_stack
1808 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1809 int *level)
1810 {
1811 struct extent_buffer *eb;
1812 int i;
1813 u64 last_snapshot;
1814 u32 nritems;
1815
1816 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1817
1818 for (i = 0; i < *level; i++) {
1819 free_extent_buffer(path->nodes[i]);
1820 path->nodes[i] = NULL;
1821 }
1822
1823 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1824 eb = path->nodes[i];
1825 nritems = btrfs_header_nritems(eb);
1826 while (path->slots[i] + 1 < nritems) {
1827 path->slots[i]++;
1828 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1829 last_snapshot)
1830 continue;
1831
1832 *level = i;
1833 return 0;
1834 }
1835 free_extent_buffer(path->nodes[i]);
1836 path->nodes[i] = NULL;
1837 }
1838 return 1;
1839 }
1840
1841 /*
1842 * walk down reloc tree to find relocated block of lowest level
1843 */
1844 static noinline_for_stack
1845 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1846 int *level)
1847 {
1848 struct extent_buffer *eb = NULL;
1849 int i;
1850 u64 bytenr;
1851 u64 ptr_gen = 0;
1852 u64 last_snapshot;
1853 u32 blocksize;
1854 u32 nritems;
1855
1856 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1857
1858 for (i = *level; i > 0; i--) {
1859 eb = path->nodes[i];
1860 nritems = btrfs_header_nritems(eb);
1861 while (path->slots[i] < nritems) {
1862 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1863 if (ptr_gen > last_snapshot)
1864 break;
1865 path->slots[i]++;
1866 }
1867 if (path->slots[i] >= nritems) {
1868 if (i == *level)
1869 break;
1870 *level = i + 1;
1871 return 0;
1872 }
1873 if (i == 1) {
1874 *level = i;
1875 return 0;
1876 }
1877
1878 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1879 blocksize = btrfs_level_size(root, i - 1);
1880 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1881 BUG_ON(btrfs_header_level(eb) != i - 1);
1882 path->nodes[i - 1] = eb;
1883 path->slots[i - 1] = 0;
1884 }
1885 return 1;
1886 }
1887
1888 /*
1889 * invalidate extent cache for file extents whose key in range of
1890 * [min_key, max_key)
1891 */
1892 static int invalidate_extent_cache(struct btrfs_root *root,
1893 struct btrfs_key *min_key,
1894 struct btrfs_key *max_key)
1895 {
1896 struct inode *inode = NULL;
1897 u64 objectid;
1898 u64 start, end;
1899 u64 ino;
1900
1901 objectid = min_key->objectid;
1902 while (1) {
1903 cond_resched();
1904 iput(inode);
1905
1906 if (objectid > max_key->objectid)
1907 break;
1908
1909 inode = find_next_inode(root, objectid);
1910 if (!inode)
1911 break;
1912 ino = btrfs_ino(inode);
1913
1914 if (ino > max_key->objectid) {
1915 iput(inode);
1916 break;
1917 }
1918
1919 objectid = ino + 1;
1920 if (!S_ISREG(inode->i_mode))
1921 continue;
1922
1923 if (unlikely(min_key->objectid == ino)) {
1924 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1925 continue;
1926 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1927 start = 0;
1928 else {
1929 start = min_key->offset;
1930 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1931 }
1932 } else {
1933 start = 0;
1934 }
1935
1936 if (unlikely(max_key->objectid == ino)) {
1937 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1938 continue;
1939 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1940 end = (u64)-1;
1941 } else {
1942 if (max_key->offset == 0)
1943 continue;
1944 end = max_key->offset;
1945 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1946 end--;
1947 }
1948 } else {
1949 end = (u64)-1;
1950 }
1951
1952 /* the lock_extent waits for readpage to complete */
1953 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1954 btrfs_drop_extent_cache(inode, start, end, 1);
1955 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
1956 }
1957 return 0;
1958 }
1959
1960 static int find_next_key(struct btrfs_path *path, int level,
1961 struct btrfs_key *key)
1962
1963 {
1964 while (level < BTRFS_MAX_LEVEL) {
1965 if (!path->nodes[level])
1966 break;
1967 if (path->slots[level] + 1 <
1968 btrfs_header_nritems(path->nodes[level])) {
1969 btrfs_node_key_to_cpu(path->nodes[level], key,
1970 path->slots[level] + 1);
1971 return 0;
1972 }
1973 level++;
1974 }
1975 return 1;
1976 }
1977
1978 /*
1979 * merge the relocated tree blocks in reloc tree with corresponding
1980 * fs tree.
1981 */
1982 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1983 struct btrfs_root *root)
1984 {
1985 LIST_HEAD(inode_list);
1986 struct btrfs_key key;
1987 struct btrfs_key next_key;
1988 struct btrfs_trans_handle *trans;
1989 struct btrfs_root *reloc_root;
1990 struct btrfs_root_item *root_item;
1991 struct btrfs_path *path;
1992 struct extent_buffer *leaf;
1993 unsigned long nr;
1994 int level;
1995 int max_level;
1996 int replaced = 0;
1997 int ret;
1998 int err = 0;
1999 u32 min_reserved;
2000
2001 path = btrfs_alloc_path();
2002 if (!path)
2003 return -ENOMEM;
2004 path->reada = 1;
2005
2006 reloc_root = root->reloc_root;
2007 root_item = &reloc_root->root_item;
2008
2009 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2010 level = btrfs_root_level(root_item);
2011 extent_buffer_get(reloc_root->node);
2012 path->nodes[level] = reloc_root->node;
2013 path->slots[level] = 0;
2014 } else {
2015 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2016
2017 level = root_item->drop_level;
2018 BUG_ON(level == 0);
2019 path->lowest_level = level;
2020 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2021 path->lowest_level = 0;
2022 if (ret < 0) {
2023 btrfs_free_path(path);
2024 return ret;
2025 }
2026
2027 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2028 path->slots[level]);
2029 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2030
2031 btrfs_unlock_up_safe(path, 0);
2032 }
2033
2034 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2035 memset(&next_key, 0, sizeof(next_key));
2036
2037 while (1) {
2038 trans = btrfs_start_transaction(root, 0);
2039 BUG_ON(IS_ERR(trans));
2040 trans->block_rsv = rc->block_rsv;
2041
2042 ret = btrfs_block_rsv_check(trans, root, rc->block_rsv,
2043 min_reserved, 0);
2044 if (ret) {
2045 BUG_ON(ret != -EAGAIN);
2046 ret = btrfs_commit_transaction(trans, root);
2047 BUG_ON(ret);
2048 continue;
2049 }
2050
2051 replaced = 0;
2052 max_level = level;
2053
2054 ret = walk_down_reloc_tree(reloc_root, path, &level);
2055 if (ret < 0) {
2056 err = ret;
2057 goto out;
2058 }
2059 if (ret > 0)
2060 break;
2061
2062 if (!find_next_key(path, level, &key) &&
2063 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2064 ret = 0;
2065 } else {
2066 ret = replace_path(trans, root, reloc_root, path,
2067 &next_key, level, max_level);
2068 }
2069 if (ret < 0) {
2070 err = ret;
2071 goto out;
2072 }
2073
2074 if (ret > 0) {
2075 level = ret;
2076 btrfs_node_key_to_cpu(path->nodes[level], &key,
2077 path->slots[level]);
2078 replaced = 1;
2079 }
2080
2081 ret = walk_up_reloc_tree(reloc_root, path, &level);
2082 if (ret > 0)
2083 break;
2084
2085 BUG_ON(level == 0);
2086 /*
2087 * save the merging progress in the drop_progress.
2088 * this is OK since root refs == 1 in this case.
2089 */
2090 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2091 path->slots[level]);
2092 root_item->drop_level = level;
2093
2094 nr = trans->blocks_used;
2095 btrfs_end_transaction_throttle(trans, root);
2096
2097 btrfs_btree_balance_dirty(root, nr);
2098
2099 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2100 invalidate_extent_cache(root, &key, &next_key);
2101 }
2102
2103 /*
2104 * handle the case only one block in the fs tree need to be
2105 * relocated and the block is tree root.
2106 */
2107 leaf = btrfs_lock_root_node(root);
2108 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2109 btrfs_tree_unlock(leaf);
2110 free_extent_buffer(leaf);
2111 if (ret < 0)
2112 err = ret;
2113 out:
2114 btrfs_free_path(path);
2115
2116 if (err == 0) {
2117 memset(&root_item->drop_progress, 0,
2118 sizeof(root_item->drop_progress));
2119 root_item->drop_level = 0;
2120 btrfs_set_root_refs(root_item, 0);
2121 btrfs_update_reloc_root(trans, root);
2122 }
2123
2124 nr = trans->blocks_used;
2125 btrfs_end_transaction_throttle(trans, root);
2126
2127 btrfs_btree_balance_dirty(root, nr);
2128
2129 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2130 invalidate_extent_cache(root, &key, &next_key);
2131
2132 return err;
2133 }
2134
2135 static noinline_for_stack
2136 int prepare_to_merge(struct reloc_control *rc, int err)
2137 {
2138 struct btrfs_root *root = rc->extent_root;
2139 struct btrfs_root *reloc_root;
2140 struct btrfs_trans_handle *trans;
2141 LIST_HEAD(reloc_roots);
2142 u64 num_bytes = 0;
2143 int ret;
2144
2145 spin_lock(&root->fs_info->trans_lock);
2146 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2147 rc->merging_rsv_size += rc->nodes_relocated * 2;
2148 spin_unlock(&root->fs_info->trans_lock);
2149 again:
2150 if (!err) {
2151 num_bytes = rc->merging_rsv_size;
2152 ret = btrfs_block_rsv_add(NULL, root, rc->block_rsv,
2153 num_bytes);
2154 if (ret)
2155 err = ret;
2156 }
2157
2158 trans = btrfs_join_transaction(rc->extent_root);
2159 if (IS_ERR(trans)) {
2160 if (!err)
2161 btrfs_block_rsv_release(rc->extent_root,
2162 rc->block_rsv, num_bytes);
2163 return PTR_ERR(trans);
2164 }
2165
2166 if (!err) {
2167 if (num_bytes != rc->merging_rsv_size) {
2168 btrfs_end_transaction(trans, rc->extent_root);
2169 btrfs_block_rsv_release(rc->extent_root,
2170 rc->block_rsv, num_bytes);
2171 goto again;
2172 }
2173 }
2174
2175 rc->merge_reloc_tree = 1;
2176
2177 while (!list_empty(&rc->reloc_roots)) {
2178 reloc_root = list_entry(rc->reloc_roots.next,
2179 struct btrfs_root, root_list);
2180 list_del_init(&reloc_root->root_list);
2181
2182 root = read_fs_root(reloc_root->fs_info,
2183 reloc_root->root_key.offset);
2184 BUG_ON(IS_ERR(root));
2185 BUG_ON(root->reloc_root != reloc_root);
2186
2187 /*
2188 * set reference count to 1, so btrfs_recover_relocation
2189 * knows it should resumes merging
2190 */
2191 if (!err)
2192 btrfs_set_root_refs(&reloc_root->root_item, 1);
2193 btrfs_update_reloc_root(trans, root);
2194
2195 list_add(&reloc_root->root_list, &reloc_roots);
2196 }
2197
2198 list_splice(&reloc_roots, &rc->reloc_roots);
2199
2200 if (!err)
2201 btrfs_commit_transaction(trans, rc->extent_root);
2202 else
2203 btrfs_end_transaction(trans, rc->extent_root);
2204 return err;
2205 }
2206
2207 static noinline_for_stack
2208 int merge_reloc_roots(struct reloc_control *rc)
2209 {
2210 struct btrfs_root *root;
2211 struct btrfs_root *reloc_root;
2212 LIST_HEAD(reloc_roots);
2213 int found = 0;
2214 int ret;
2215 again:
2216 root = rc->extent_root;
2217 spin_lock(&root->fs_info->trans_lock);
2218 list_splice_init(&rc->reloc_roots, &reloc_roots);
2219 spin_unlock(&root->fs_info->trans_lock);
2220
2221 while (!list_empty(&reloc_roots)) {
2222 found = 1;
2223 reloc_root = list_entry(reloc_roots.next,
2224 struct btrfs_root, root_list);
2225
2226 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2227 root = read_fs_root(reloc_root->fs_info,
2228 reloc_root->root_key.offset);
2229 BUG_ON(IS_ERR(root));
2230 BUG_ON(root->reloc_root != reloc_root);
2231
2232 ret = merge_reloc_root(rc, root);
2233 BUG_ON(ret);
2234 } else {
2235 list_del_init(&reloc_root->root_list);
2236 }
2237 btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0);
2238 }
2239
2240 if (found) {
2241 found = 0;
2242 goto again;
2243 }
2244 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2245 return 0;
2246 }
2247
2248 static void free_block_list(struct rb_root *blocks)
2249 {
2250 struct tree_block *block;
2251 struct rb_node *rb_node;
2252 while ((rb_node = rb_first(blocks))) {
2253 block = rb_entry(rb_node, struct tree_block, rb_node);
2254 rb_erase(rb_node, blocks);
2255 kfree(block);
2256 }
2257 }
2258
2259 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2260 struct btrfs_root *reloc_root)
2261 {
2262 struct btrfs_root *root;
2263
2264 if (reloc_root->last_trans == trans->transid)
2265 return 0;
2266
2267 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2268 BUG_ON(IS_ERR(root));
2269 BUG_ON(root->reloc_root != reloc_root);
2270
2271 return btrfs_record_root_in_trans(trans, root);
2272 }
2273
2274 static noinline_for_stack
2275 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2276 struct reloc_control *rc,
2277 struct backref_node *node,
2278 struct backref_edge *edges[], int *nr)
2279 {
2280 struct backref_node *next;
2281 struct btrfs_root *root;
2282 int index = 0;
2283
2284 next = node;
2285 while (1) {
2286 cond_resched();
2287 next = walk_up_backref(next, edges, &index);
2288 root = next->root;
2289 BUG_ON(!root);
2290 BUG_ON(!root->ref_cows);
2291
2292 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2293 record_reloc_root_in_trans(trans, root);
2294 break;
2295 }
2296
2297 btrfs_record_root_in_trans(trans, root);
2298 root = root->reloc_root;
2299
2300 if (next->new_bytenr != root->node->start) {
2301 BUG_ON(next->new_bytenr);
2302 BUG_ON(!list_empty(&next->list));
2303 next->new_bytenr = root->node->start;
2304 next->root = root;
2305 list_add_tail(&next->list,
2306 &rc->backref_cache.changed);
2307 __mark_block_processed(rc, next);
2308 break;
2309 }
2310
2311 WARN_ON(1);
2312 root = NULL;
2313 next = walk_down_backref(edges, &index);
2314 if (!next || next->level <= node->level)
2315 break;
2316 }
2317 if (!root)
2318 return NULL;
2319
2320 *nr = index;
2321 next = node;
2322 /* setup backref node path for btrfs_reloc_cow_block */
2323 while (1) {
2324 rc->backref_cache.path[next->level] = next;
2325 if (--index < 0)
2326 break;
2327 next = edges[index]->node[UPPER];
2328 }
2329 return root;
2330 }
2331
2332 /*
2333 * select a tree root for relocation. return NULL if the block
2334 * is reference counted. we should use do_relocation() in this
2335 * case. return a tree root pointer if the block isn't reference
2336 * counted. return -ENOENT if the block is root of reloc tree.
2337 */
2338 static noinline_for_stack
2339 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2340 struct backref_node *node)
2341 {
2342 struct backref_node *next;
2343 struct btrfs_root *root;
2344 struct btrfs_root *fs_root = NULL;
2345 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2346 int index = 0;
2347
2348 next = node;
2349 while (1) {
2350 cond_resched();
2351 next = walk_up_backref(next, edges, &index);
2352 root = next->root;
2353 BUG_ON(!root);
2354
2355 /* no other choice for non-references counted tree */
2356 if (!root->ref_cows)
2357 return root;
2358
2359 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2360 fs_root = root;
2361
2362 if (next != node)
2363 return NULL;
2364
2365 next = walk_down_backref(edges, &index);
2366 if (!next || next->level <= node->level)
2367 break;
2368 }
2369
2370 if (!fs_root)
2371 return ERR_PTR(-ENOENT);
2372 return fs_root;
2373 }
2374
2375 static noinline_for_stack
2376 u64 calcu_metadata_size(struct reloc_control *rc,
2377 struct backref_node *node, int reserve)
2378 {
2379 struct backref_node *next = node;
2380 struct backref_edge *edge;
2381 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2382 u64 num_bytes = 0;
2383 int index = 0;
2384
2385 BUG_ON(reserve && node->processed);
2386
2387 while (next) {
2388 cond_resched();
2389 while (1) {
2390 if (next->processed && (reserve || next != node))
2391 break;
2392
2393 num_bytes += btrfs_level_size(rc->extent_root,
2394 next->level);
2395
2396 if (list_empty(&next->upper))
2397 break;
2398
2399 edge = list_entry(next->upper.next,
2400 struct backref_edge, list[LOWER]);
2401 edges[index++] = edge;
2402 next = edge->node[UPPER];
2403 }
2404 next = walk_down_backref(edges, &index);
2405 }
2406 return num_bytes;
2407 }
2408
2409 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2410 struct reloc_control *rc,
2411 struct backref_node *node)
2412 {
2413 struct btrfs_root *root = rc->extent_root;
2414 u64 num_bytes;
2415 int ret;
2416
2417 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2418
2419 trans->block_rsv = rc->block_rsv;
2420 ret = btrfs_block_rsv_add(trans, root, rc->block_rsv, num_bytes);
2421 if (ret) {
2422 if (ret == -EAGAIN)
2423 rc->commit_transaction = 1;
2424 return ret;
2425 }
2426
2427 return 0;
2428 }
2429
2430 static void release_metadata_space(struct reloc_control *rc,
2431 struct backref_node *node)
2432 {
2433 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2434 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2435 }
2436
2437 /*
2438 * relocate a block tree, and then update pointers in upper level
2439 * blocks that reference the block to point to the new location.
2440 *
2441 * if called by link_to_upper, the block has already been relocated.
2442 * in that case this function just updates pointers.
2443 */
2444 static int do_relocation(struct btrfs_trans_handle *trans,
2445 struct reloc_control *rc,
2446 struct backref_node *node,
2447 struct btrfs_key *key,
2448 struct btrfs_path *path, int lowest)
2449 {
2450 struct backref_node *upper;
2451 struct backref_edge *edge;
2452 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2453 struct btrfs_root *root;
2454 struct extent_buffer *eb;
2455 u32 blocksize;
2456 u64 bytenr;
2457 u64 generation;
2458 int nr;
2459 int slot;
2460 int ret;
2461 int err = 0;
2462
2463 BUG_ON(lowest && node->eb);
2464
2465 path->lowest_level = node->level + 1;
2466 rc->backref_cache.path[node->level] = node;
2467 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2468 cond_resched();
2469
2470 upper = edge->node[UPPER];
2471 root = select_reloc_root(trans, rc, upper, edges, &nr);
2472 BUG_ON(!root);
2473
2474 if (upper->eb && !upper->locked) {
2475 if (!lowest) {
2476 ret = btrfs_bin_search(upper->eb, key,
2477 upper->level, &slot);
2478 BUG_ON(ret);
2479 bytenr = btrfs_node_blockptr(upper->eb, slot);
2480 if (node->eb->start == bytenr)
2481 goto next;
2482 }
2483 drop_node_buffer(upper);
2484 }
2485
2486 if (!upper->eb) {
2487 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2488 if (ret < 0) {
2489 err = ret;
2490 break;
2491 }
2492 BUG_ON(ret > 0);
2493
2494 if (!upper->eb) {
2495 upper->eb = path->nodes[upper->level];
2496 path->nodes[upper->level] = NULL;
2497 } else {
2498 BUG_ON(upper->eb != path->nodes[upper->level]);
2499 }
2500
2501 upper->locked = 1;
2502 path->locks[upper->level] = 0;
2503
2504 slot = path->slots[upper->level];
2505 btrfs_release_path(path);
2506 } else {
2507 ret = btrfs_bin_search(upper->eb, key, upper->level,
2508 &slot);
2509 BUG_ON(ret);
2510 }
2511
2512 bytenr = btrfs_node_blockptr(upper->eb, slot);
2513 if (lowest) {
2514 BUG_ON(bytenr != node->bytenr);
2515 } else {
2516 if (node->eb->start == bytenr)
2517 goto next;
2518 }
2519
2520 blocksize = btrfs_level_size(root, node->level);
2521 generation = btrfs_node_ptr_generation(upper->eb, slot);
2522 eb = read_tree_block(root, bytenr, blocksize, generation);
2523 if (!eb) {
2524 err = -EIO;
2525 goto next;
2526 }
2527 btrfs_tree_lock(eb);
2528 btrfs_set_lock_blocking(eb);
2529
2530 if (!node->eb) {
2531 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2532 slot, &eb);
2533 btrfs_tree_unlock(eb);
2534 free_extent_buffer(eb);
2535 if (ret < 0) {
2536 err = ret;
2537 goto next;
2538 }
2539 BUG_ON(node->eb != eb);
2540 } else {
2541 btrfs_set_node_blockptr(upper->eb, slot,
2542 node->eb->start);
2543 btrfs_set_node_ptr_generation(upper->eb, slot,
2544 trans->transid);
2545 btrfs_mark_buffer_dirty(upper->eb);
2546
2547 ret = btrfs_inc_extent_ref(trans, root,
2548 node->eb->start, blocksize,
2549 upper->eb->start,
2550 btrfs_header_owner(upper->eb),
2551 node->level, 0);
2552 BUG_ON(ret);
2553
2554 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2555 BUG_ON(ret);
2556 }
2557 next:
2558 if (!upper->pending)
2559 drop_node_buffer(upper);
2560 else
2561 unlock_node_buffer(upper);
2562 if (err)
2563 break;
2564 }
2565
2566 if (!err && node->pending) {
2567 drop_node_buffer(node);
2568 list_move_tail(&node->list, &rc->backref_cache.changed);
2569 node->pending = 0;
2570 }
2571
2572 path->lowest_level = 0;
2573 BUG_ON(err == -ENOSPC);
2574 return err;
2575 }
2576
2577 static int link_to_upper(struct btrfs_trans_handle *trans,
2578 struct reloc_control *rc,
2579 struct backref_node *node,
2580 struct btrfs_path *path)
2581 {
2582 struct btrfs_key key;
2583
2584 btrfs_node_key_to_cpu(node->eb, &key, 0);
2585 return do_relocation(trans, rc, node, &key, path, 0);
2586 }
2587
2588 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2589 struct reloc_control *rc,
2590 struct btrfs_path *path, int err)
2591 {
2592 LIST_HEAD(list);
2593 struct backref_cache *cache = &rc->backref_cache;
2594 struct backref_node *node;
2595 int level;
2596 int ret;
2597
2598 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2599 while (!list_empty(&cache->pending[level])) {
2600 node = list_entry(cache->pending[level].next,
2601 struct backref_node, list);
2602 list_move_tail(&node->list, &list);
2603 BUG_ON(!node->pending);
2604
2605 if (!err) {
2606 ret = link_to_upper(trans, rc, node, path);
2607 if (ret < 0)
2608 err = ret;
2609 }
2610 }
2611 list_splice_init(&list, &cache->pending[level]);
2612 }
2613 return err;
2614 }
2615
2616 static void mark_block_processed(struct reloc_control *rc,
2617 u64 bytenr, u32 blocksize)
2618 {
2619 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2620 EXTENT_DIRTY, GFP_NOFS);
2621 }
2622
2623 static void __mark_block_processed(struct reloc_control *rc,
2624 struct backref_node *node)
2625 {
2626 u32 blocksize;
2627 if (node->level == 0 ||
2628 in_block_group(node->bytenr, rc->block_group)) {
2629 blocksize = btrfs_level_size(rc->extent_root, node->level);
2630 mark_block_processed(rc, node->bytenr, blocksize);
2631 }
2632 node->processed = 1;
2633 }
2634
2635 /*
2636 * mark a block and all blocks directly/indirectly reference the block
2637 * as processed.
2638 */
2639 static void update_processed_blocks(struct reloc_control *rc,
2640 struct backref_node *node)
2641 {
2642 struct backref_node *next = node;
2643 struct backref_edge *edge;
2644 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2645 int index = 0;
2646
2647 while (next) {
2648 cond_resched();
2649 while (1) {
2650 if (next->processed)
2651 break;
2652
2653 __mark_block_processed(rc, next);
2654
2655 if (list_empty(&next->upper))
2656 break;
2657
2658 edge = list_entry(next->upper.next,
2659 struct backref_edge, list[LOWER]);
2660 edges[index++] = edge;
2661 next = edge->node[UPPER];
2662 }
2663 next = walk_down_backref(edges, &index);
2664 }
2665 }
2666
2667 static int tree_block_processed(u64 bytenr, u32 blocksize,
2668 struct reloc_control *rc)
2669 {
2670 if (test_range_bit(&rc->processed_blocks, bytenr,
2671 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2672 return 1;
2673 return 0;
2674 }
2675
2676 static int get_tree_block_key(struct reloc_control *rc,
2677 struct tree_block *block)
2678 {
2679 struct extent_buffer *eb;
2680
2681 BUG_ON(block->key_ready);
2682 eb = read_tree_block(rc->extent_root, block->bytenr,
2683 block->key.objectid, block->key.offset);
2684 BUG_ON(!eb);
2685 WARN_ON(btrfs_header_level(eb) != block->level);
2686 if (block->level == 0)
2687 btrfs_item_key_to_cpu(eb, &block->key, 0);
2688 else
2689 btrfs_node_key_to_cpu(eb, &block->key, 0);
2690 free_extent_buffer(eb);
2691 block->key_ready = 1;
2692 return 0;
2693 }
2694
2695 static int reada_tree_block(struct reloc_control *rc,
2696 struct tree_block *block)
2697 {
2698 BUG_ON(block->key_ready);
2699 readahead_tree_block(rc->extent_root, block->bytenr,
2700 block->key.objectid, block->key.offset);
2701 return 0;
2702 }
2703
2704 /*
2705 * helper function to relocate a tree block
2706 */
2707 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2708 struct reloc_control *rc,
2709 struct backref_node *node,
2710 struct btrfs_key *key,
2711 struct btrfs_path *path)
2712 {
2713 struct btrfs_root *root;
2714 int release = 0;
2715 int ret = 0;
2716
2717 if (!node)
2718 return 0;
2719
2720 BUG_ON(node->processed);
2721 root = select_one_root(trans, node);
2722 if (root == ERR_PTR(-ENOENT)) {
2723 update_processed_blocks(rc, node);
2724 goto out;
2725 }
2726
2727 if (!root || root->ref_cows) {
2728 ret = reserve_metadata_space(trans, rc, node);
2729 if (ret)
2730 goto out;
2731 release = 1;
2732 }
2733
2734 if (root) {
2735 if (root->ref_cows) {
2736 BUG_ON(node->new_bytenr);
2737 BUG_ON(!list_empty(&node->list));
2738 btrfs_record_root_in_trans(trans, root);
2739 root = root->reloc_root;
2740 node->new_bytenr = root->node->start;
2741 node->root = root;
2742 list_add_tail(&node->list, &rc->backref_cache.changed);
2743 } else {
2744 path->lowest_level = node->level;
2745 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2746 btrfs_release_path(path);
2747 if (ret > 0)
2748 ret = 0;
2749 }
2750 if (!ret)
2751 update_processed_blocks(rc, node);
2752 } else {
2753 ret = do_relocation(trans, rc, node, key, path, 1);
2754 }
2755 out:
2756 if (ret || node->level == 0 || node->cowonly) {
2757 if (release)
2758 release_metadata_space(rc, node);
2759 remove_backref_node(&rc->backref_cache, node);
2760 }
2761 return ret;
2762 }
2763
2764 /*
2765 * relocate a list of blocks
2766 */
2767 static noinline_for_stack
2768 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2769 struct reloc_control *rc, struct rb_root *blocks)
2770 {
2771 struct backref_node *node;
2772 struct btrfs_path *path;
2773 struct tree_block *block;
2774 struct rb_node *rb_node;
2775 int ret;
2776 int err = 0;
2777
2778 path = btrfs_alloc_path();
2779 if (!path)
2780 return -ENOMEM;
2781
2782 rb_node = rb_first(blocks);
2783 while (rb_node) {
2784 block = rb_entry(rb_node, struct tree_block, rb_node);
2785 if (!block->key_ready)
2786 reada_tree_block(rc, block);
2787 rb_node = rb_next(rb_node);
2788 }
2789
2790 rb_node = rb_first(blocks);
2791 while (rb_node) {
2792 block = rb_entry(rb_node, struct tree_block, rb_node);
2793 if (!block->key_ready)
2794 get_tree_block_key(rc, block);
2795 rb_node = rb_next(rb_node);
2796 }
2797
2798 rb_node = rb_first(blocks);
2799 while (rb_node) {
2800 block = rb_entry(rb_node, struct tree_block, rb_node);
2801
2802 node = build_backref_tree(rc, &block->key,
2803 block->level, block->bytenr);
2804 if (IS_ERR(node)) {
2805 err = PTR_ERR(node);
2806 goto out;
2807 }
2808
2809 ret = relocate_tree_block(trans, rc, node, &block->key,
2810 path);
2811 if (ret < 0) {
2812 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2813 err = ret;
2814 goto out;
2815 }
2816 rb_node = rb_next(rb_node);
2817 }
2818 out:
2819 free_block_list(blocks);
2820 err = finish_pending_nodes(trans, rc, path, err);
2821
2822 btrfs_free_path(path);
2823 return err;
2824 }
2825
2826 static noinline_for_stack
2827 int prealloc_file_extent_cluster(struct inode *inode,
2828 struct file_extent_cluster *cluster)
2829 {
2830 u64 alloc_hint = 0;
2831 u64 start;
2832 u64 end;
2833 u64 offset = BTRFS_I(inode)->index_cnt;
2834 u64 num_bytes;
2835 int nr = 0;
2836 int ret = 0;
2837
2838 BUG_ON(cluster->start != cluster->boundary[0]);
2839 mutex_lock(&inode->i_mutex);
2840
2841 ret = btrfs_check_data_free_space(inode, cluster->end +
2842 1 - cluster->start);
2843 if (ret)
2844 goto out;
2845
2846 while (nr < cluster->nr) {
2847 start = cluster->boundary[nr] - offset;
2848 if (nr + 1 < cluster->nr)
2849 end = cluster->boundary[nr + 1] - 1 - offset;
2850 else
2851 end = cluster->end - offset;
2852
2853 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2854 num_bytes = end + 1 - start;
2855 ret = btrfs_prealloc_file_range(inode, 0, start,
2856 num_bytes, num_bytes,
2857 end + 1, &alloc_hint);
2858 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2859 if (ret)
2860 break;
2861 nr++;
2862 }
2863 btrfs_free_reserved_data_space(inode, cluster->end +
2864 1 - cluster->start);
2865 out:
2866 mutex_unlock(&inode->i_mutex);
2867 return ret;
2868 }
2869
2870 static noinline_for_stack
2871 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2872 u64 block_start)
2873 {
2874 struct btrfs_root *root = BTRFS_I(inode)->root;
2875 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2876 struct extent_map *em;
2877 int ret = 0;
2878
2879 em = alloc_extent_map();
2880 if (!em)
2881 return -ENOMEM;
2882
2883 em->start = start;
2884 em->len = end + 1 - start;
2885 em->block_len = em->len;
2886 em->block_start = block_start;
2887 em->bdev = root->fs_info->fs_devices->latest_bdev;
2888 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2889
2890 lock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2891 while (1) {
2892 write_lock(&em_tree->lock);
2893 ret = add_extent_mapping(em_tree, em);
2894 write_unlock(&em_tree->lock);
2895 if (ret != -EEXIST) {
2896 free_extent_map(em);
2897 break;
2898 }
2899 btrfs_drop_extent_cache(inode, start, end, 0);
2900 }
2901 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, GFP_NOFS);
2902 return ret;
2903 }
2904
2905 static int relocate_file_extent_cluster(struct inode *inode,
2906 struct file_extent_cluster *cluster)
2907 {
2908 u64 page_start;
2909 u64 page_end;
2910 u64 offset = BTRFS_I(inode)->index_cnt;
2911 unsigned long index;
2912 unsigned long last_index;
2913 struct page *page;
2914 struct file_ra_state *ra;
2915 int nr = 0;
2916 int ret = 0;
2917
2918 if (!cluster->nr)
2919 return 0;
2920
2921 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2922 if (!ra)
2923 return -ENOMEM;
2924
2925 ret = prealloc_file_extent_cluster(inode, cluster);
2926 if (ret)
2927 goto out;
2928
2929 file_ra_state_init(ra, inode->i_mapping);
2930
2931 ret = setup_extent_mapping(inode, cluster->start - offset,
2932 cluster->end - offset, cluster->start);
2933 if (ret)
2934 goto out;
2935
2936 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2937 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2938 while (index <= last_index) {
2939 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2940 if (ret)
2941 goto out;
2942
2943 page = find_lock_page(inode->i_mapping, index);
2944 if (!page) {
2945 page_cache_sync_readahead(inode->i_mapping,
2946 ra, NULL, index,
2947 last_index + 1 - index);
2948 page = grab_cache_page(inode->i_mapping, index);
2949 if (!page) {
2950 btrfs_delalloc_release_metadata(inode,
2951 PAGE_CACHE_SIZE);
2952 ret = -ENOMEM;
2953 goto out;
2954 }
2955 }
2956
2957 if (PageReadahead(page)) {
2958 page_cache_async_readahead(inode->i_mapping,
2959 ra, NULL, page, index,
2960 last_index + 1 - index);
2961 }
2962
2963 if (!PageUptodate(page)) {
2964 btrfs_readpage(NULL, page);
2965 lock_page(page);
2966 if (!PageUptodate(page)) {
2967 unlock_page(page);
2968 page_cache_release(page);
2969 btrfs_delalloc_release_metadata(inode,
2970 PAGE_CACHE_SIZE);
2971 ret = -EIO;
2972 goto out;
2973 }
2974 }
2975
2976 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
2977 page_end = page_start + PAGE_CACHE_SIZE - 1;
2978
2979 lock_extent(&BTRFS_I(inode)->io_tree,
2980 page_start, page_end, GFP_NOFS);
2981
2982 set_page_extent_mapped(page);
2983
2984 if (nr < cluster->nr &&
2985 page_start + offset == cluster->boundary[nr]) {
2986 set_extent_bits(&BTRFS_I(inode)->io_tree,
2987 page_start, page_end,
2988 EXTENT_BOUNDARY, GFP_NOFS);
2989 nr++;
2990 }
2991
2992 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
2993 set_page_dirty(page);
2994
2995 unlock_extent(&BTRFS_I(inode)->io_tree,
2996 page_start, page_end, GFP_NOFS);
2997 unlock_page(page);
2998 page_cache_release(page);
2999
3000 index++;
3001 balance_dirty_pages_ratelimited(inode->i_mapping);
3002 btrfs_throttle(BTRFS_I(inode)->root);
3003 }
3004 WARN_ON(nr != cluster->nr);
3005 out:
3006 kfree(ra);
3007 return ret;
3008 }
3009
3010 static noinline_for_stack
3011 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3012 struct file_extent_cluster *cluster)
3013 {
3014 int ret;
3015
3016 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3017 ret = relocate_file_extent_cluster(inode, cluster);
3018 if (ret)
3019 return ret;
3020 cluster->nr = 0;
3021 }
3022
3023 if (!cluster->nr)
3024 cluster->start = extent_key->objectid;
3025 else
3026 BUG_ON(cluster->nr >= MAX_EXTENTS);
3027 cluster->end = extent_key->objectid + extent_key->offset - 1;
3028 cluster->boundary[cluster->nr] = extent_key->objectid;
3029 cluster->nr++;
3030
3031 if (cluster->nr >= MAX_EXTENTS) {
3032 ret = relocate_file_extent_cluster(inode, cluster);
3033 if (ret)
3034 return ret;
3035 cluster->nr = 0;
3036 }
3037 return 0;
3038 }
3039
3040 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3041 static int get_ref_objectid_v0(struct reloc_control *rc,
3042 struct btrfs_path *path,
3043 struct btrfs_key *extent_key,
3044 u64 *ref_objectid, int *path_change)
3045 {
3046 struct btrfs_key key;
3047 struct extent_buffer *leaf;
3048 struct btrfs_extent_ref_v0 *ref0;
3049 int ret;
3050 int slot;
3051
3052 leaf = path->nodes[0];
3053 slot = path->slots[0];
3054 while (1) {
3055 if (slot >= btrfs_header_nritems(leaf)) {
3056 ret = btrfs_next_leaf(rc->extent_root, path);
3057 if (ret < 0)
3058 return ret;
3059 BUG_ON(ret > 0);
3060 leaf = path->nodes[0];
3061 slot = path->slots[0];
3062 if (path_change)
3063 *path_change = 1;
3064 }
3065 btrfs_item_key_to_cpu(leaf, &key, slot);
3066 if (key.objectid != extent_key->objectid)
3067 return -ENOENT;
3068
3069 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3070 slot++;
3071 continue;
3072 }
3073 ref0 = btrfs_item_ptr(leaf, slot,
3074 struct btrfs_extent_ref_v0);
3075 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3076 break;
3077 }
3078 return 0;
3079 }
3080 #endif
3081
3082 /*
3083 * helper to add a tree block to the list.
3084 * the major work is getting the generation and level of the block
3085 */
3086 static int add_tree_block(struct reloc_control *rc,
3087 struct btrfs_key *extent_key,
3088 struct btrfs_path *path,
3089 struct rb_root *blocks)
3090 {
3091 struct extent_buffer *eb;
3092 struct btrfs_extent_item *ei;
3093 struct btrfs_tree_block_info *bi;
3094 struct tree_block *block;
3095 struct rb_node *rb_node;
3096 u32 item_size;
3097 int level = -1;
3098 int generation;
3099
3100 eb = path->nodes[0];
3101 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3102
3103 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3104 ei = btrfs_item_ptr(eb, path->slots[0],
3105 struct btrfs_extent_item);
3106 bi = (struct btrfs_tree_block_info *)(ei + 1);
3107 generation = btrfs_extent_generation(eb, ei);
3108 level = btrfs_tree_block_level(eb, bi);
3109 } else {
3110 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3111 u64 ref_owner;
3112 int ret;
3113
3114 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3115 ret = get_ref_objectid_v0(rc, path, extent_key,
3116 &ref_owner, NULL);
3117 if (ret < 0)
3118 return ret;
3119 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3120 level = (int)ref_owner;
3121 /* FIXME: get real generation */
3122 generation = 0;
3123 #else
3124 BUG();
3125 #endif
3126 }
3127
3128 btrfs_release_path(path);
3129
3130 BUG_ON(level == -1);
3131
3132 block = kmalloc(sizeof(*block), GFP_NOFS);
3133 if (!block)
3134 return -ENOMEM;
3135
3136 block->bytenr = extent_key->objectid;
3137 block->key.objectid = extent_key->offset;
3138 block->key.offset = generation;
3139 block->level = level;
3140 block->key_ready = 0;
3141
3142 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3143 BUG_ON(rb_node);
3144
3145 return 0;
3146 }
3147
3148 /*
3149 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3150 */
3151 static int __add_tree_block(struct reloc_control *rc,
3152 u64 bytenr, u32 blocksize,
3153 struct rb_root *blocks)
3154 {
3155 struct btrfs_path *path;
3156 struct btrfs_key key;
3157 int ret;
3158
3159 if (tree_block_processed(bytenr, blocksize, rc))
3160 return 0;
3161
3162 if (tree_search(blocks, bytenr))
3163 return 0;
3164
3165 path = btrfs_alloc_path();
3166 if (!path)
3167 return -ENOMEM;
3168
3169 key.objectid = bytenr;
3170 key.type = BTRFS_EXTENT_ITEM_KEY;
3171 key.offset = blocksize;
3172
3173 path->search_commit_root = 1;
3174 path->skip_locking = 1;
3175 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3176 if (ret < 0)
3177 goto out;
3178 BUG_ON(ret);
3179
3180 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3181 ret = add_tree_block(rc, &key, path, blocks);
3182 out:
3183 btrfs_free_path(path);
3184 return ret;
3185 }
3186
3187 /*
3188 * helper to check if the block use full backrefs for pointers in it
3189 */
3190 static int block_use_full_backref(struct reloc_control *rc,
3191 struct extent_buffer *eb)
3192 {
3193 u64 flags;
3194 int ret;
3195
3196 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3197 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3198 return 1;
3199
3200 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3201 eb->start, eb->len, NULL, &flags);
3202 BUG_ON(ret);
3203
3204 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3205 ret = 1;
3206 else
3207 ret = 0;
3208 return ret;
3209 }
3210
3211 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3212 struct inode *inode, u64 ino)
3213 {
3214 struct btrfs_key key;
3215 struct btrfs_path *path;
3216 struct btrfs_root *root = fs_info->tree_root;
3217 struct btrfs_trans_handle *trans;
3218 unsigned long nr;
3219 int ret = 0;
3220
3221 if (inode)
3222 goto truncate;
3223
3224 key.objectid = ino;
3225 key.type = BTRFS_INODE_ITEM_KEY;
3226 key.offset = 0;
3227
3228 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3229 if (IS_ERR_OR_NULL(inode) || is_bad_inode(inode)) {
3230 if (inode && !IS_ERR(inode))
3231 iput(inode);
3232 return -ENOENT;
3233 }
3234
3235 truncate:
3236 path = btrfs_alloc_path();
3237 if (!path) {
3238 ret = -ENOMEM;
3239 goto out;
3240 }
3241
3242 trans = btrfs_join_transaction(root);
3243 if (IS_ERR(trans)) {
3244 btrfs_free_path(path);
3245 ret = PTR_ERR(trans);
3246 goto out;
3247 }
3248
3249 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3250
3251 btrfs_free_path(path);
3252 nr = trans->blocks_used;
3253 btrfs_end_transaction(trans, root);
3254 btrfs_btree_balance_dirty(root, nr);
3255 out:
3256 iput(inode);
3257 return ret;
3258 }
3259
3260 /*
3261 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3262 * this function scans fs tree to find blocks reference the data extent
3263 */
3264 static int find_data_references(struct reloc_control *rc,
3265 struct btrfs_key *extent_key,
3266 struct extent_buffer *leaf,
3267 struct btrfs_extent_data_ref *ref,
3268 struct rb_root *blocks)
3269 {
3270 struct btrfs_path *path;
3271 struct tree_block *block;
3272 struct btrfs_root *root;
3273 struct btrfs_file_extent_item *fi;
3274 struct rb_node *rb_node;
3275 struct btrfs_key key;
3276 u64 ref_root;
3277 u64 ref_objectid;
3278 u64 ref_offset;
3279 u32 ref_count;
3280 u32 nritems;
3281 int err = 0;
3282 int added = 0;
3283 int counted;
3284 int ret;
3285
3286 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3287 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3288 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3289 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3290
3291 /*
3292 * This is an extent belonging to the free space cache, lets just delete
3293 * it and redo the search.
3294 */
3295 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3296 ret = delete_block_group_cache(rc->extent_root->fs_info,
3297 NULL, ref_objectid);
3298 if (ret != -ENOENT)
3299 return ret;
3300 ret = 0;
3301 }
3302
3303 path = btrfs_alloc_path();
3304 if (!path)
3305 return -ENOMEM;
3306 path->reada = 1;
3307
3308 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3309 if (IS_ERR(root)) {
3310 err = PTR_ERR(root);
3311 goto out;
3312 }
3313
3314 key.objectid = ref_objectid;
3315 key.offset = ref_offset;
3316 key.type = BTRFS_EXTENT_DATA_KEY;
3317
3318 path->search_commit_root = 1;
3319 path->skip_locking = 1;
3320 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3321 if (ret < 0) {
3322 err = ret;
3323 goto out;
3324 }
3325
3326 leaf = path->nodes[0];
3327 nritems = btrfs_header_nritems(leaf);
3328 /*
3329 * the references in tree blocks that use full backrefs
3330 * are not counted in
3331 */
3332 if (block_use_full_backref(rc, leaf))
3333 counted = 0;
3334 else
3335 counted = 1;
3336 rb_node = tree_search(blocks, leaf->start);
3337 if (rb_node) {
3338 if (counted)
3339 added = 1;
3340 else
3341 path->slots[0] = nritems;
3342 }
3343
3344 while (ref_count > 0) {
3345 while (path->slots[0] >= nritems) {
3346 ret = btrfs_next_leaf(root, path);
3347 if (ret < 0) {
3348 err = ret;
3349 goto out;
3350 }
3351 if (ret > 0) {
3352 WARN_ON(1);
3353 goto out;
3354 }
3355
3356 leaf = path->nodes[0];
3357 nritems = btrfs_header_nritems(leaf);
3358 added = 0;
3359
3360 if (block_use_full_backref(rc, leaf))
3361 counted = 0;
3362 else
3363 counted = 1;
3364 rb_node = tree_search(blocks, leaf->start);
3365 if (rb_node) {
3366 if (counted)
3367 added = 1;
3368 else
3369 path->slots[0] = nritems;
3370 }
3371 }
3372
3373 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3374 if (key.objectid != ref_objectid ||
3375 key.type != BTRFS_EXTENT_DATA_KEY) {
3376 WARN_ON(1);
3377 break;
3378 }
3379
3380 fi = btrfs_item_ptr(leaf, path->slots[0],
3381 struct btrfs_file_extent_item);
3382
3383 if (btrfs_file_extent_type(leaf, fi) ==
3384 BTRFS_FILE_EXTENT_INLINE)
3385 goto next;
3386
3387 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3388 extent_key->objectid)
3389 goto next;
3390
3391 key.offset -= btrfs_file_extent_offset(leaf, fi);
3392 if (key.offset != ref_offset)
3393 goto next;
3394
3395 if (counted)
3396 ref_count--;
3397 if (added)
3398 goto next;
3399
3400 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3401 block = kmalloc(sizeof(*block), GFP_NOFS);
3402 if (!block) {
3403 err = -ENOMEM;
3404 break;
3405 }
3406 block->bytenr = leaf->start;
3407 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3408 block->level = 0;
3409 block->key_ready = 1;
3410 rb_node = tree_insert(blocks, block->bytenr,
3411 &block->rb_node);
3412 BUG_ON(rb_node);
3413 }
3414 if (counted)
3415 added = 1;
3416 else
3417 path->slots[0] = nritems;
3418 next:
3419 path->slots[0]++;
3420
3421 }
3422 out:
3423 btrfs_free_path(path);
3424 return err;
3425 }
3426
3427 /*
3428 * hepler to find all tree blocks that reference a given data extent
3429 */
3430 static noinline_for_stack
3431 int add_data_references(struct reloc_control *rc,
3432 struct btrfs_key *extent_key,
3433 struct btrfs_path *path,
3434 struct rb_root *blocks)
3435 {
3436 struct btrfs_key key;
3437 struct extent_buffer *eb;
3438 struct btrfs_extent_data_ref *dref;
3439 struct btrfs_extent_inline_ref *iref;
3440 unsigned long ptr;
3441 unsigned long end;
3442 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3443 int ret;
3444 int err = 0;
3445
3446 eb = path->nodes[0];
3447 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3448 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3449 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3450 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3451 ptr = end;
3452 else
3453 #endif
3454 ptr += sizeof(struct btrfs_extent_item);
3455
3456 while (ptr < end) {
3457 iref = (struct btrfs_extent_inline_ref *)ptr;
3458 key.type = btrfs_extent_inline_ref_type(eb, iref);
3459 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3460 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3461 ret = __add_tree_block(rc, key.offset, blocksize,
3462 blocks);
3463 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3464 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3465 ret = find_data_references(rc, extent_key,
3466 eb, dref, blocks);
3467 } else {
3468 BUG();
3469 }
3470 ptr += btrfs_extent_inline_ref_size(key.type);
3471 }
3472 WARN_ON(ptr > end);
3473
3474 while (1) {
3475 cond_resched();
3476 eb = path->nodes[0];
3477 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3478 ret = btrfs_next_leaf(rc->extent_root, path);
3479 if (ret < 0) {
3480 err = ret;
3481 break;
3482 }
3483 if (ret > 0)
3484 break;
3485 eb = path->nodes[0];
3486 }
3487
3488 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3489 if (key.objectid != extent_key->objectid)
3490 break;
3491
3492 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3493 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3494 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3495 #else
3496 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3497 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3498 #endif
3499 ret = __add_tree_block(rc, key.offset, blocksize,
3500 blocks);
3501 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3502 dref = btrfs_item_ptr(eb, path->slots[0],
3503 struct btrfs_extent_data_ref);
3504 ret = find_data_references(rc, extent_key,
3505 eb, dref, blocks);
3506 } else {
3507 ret = 0;
3508 }
3509 if (ret) {
3510 err = ret;
3511 break;
3512 }
3513 path->slots[0]++;
3514 }
3515 btrfs_release_path(path);
3516 if (err)
3517 free_block_list(blocks);
3518 return err;
3519 }
3520
3521 /*
3522 * hepler to find next unprocessed extent
3523 */
3524 static noinline_for_stack
3525 int find_next_extent(struct btrfs_trans_handle *trans,
3526 struct reloc_control *rc, struct btrfs_path *path,
3527 struct btrfs_key *extent_key)
3528 {
3529 struct btrfs_key key;
3530 struct extent_buffer *leaf;
3531 u64 start, end, last;
3532 int ret;
3533
3534 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3535 while (1) {
3536 cond_resched();
3537 if (rc->search_start >= last) {
3538 ret = 1;
3539 break;
3540 }
3541
3542 key.objectid = rc->search_start;
3543 key.type = BTRFS_EXTENT_ITEM_KEY;
3544 key.offset = 0;
3545
3546 path->search_commit_root = 1;
3547 path->skip_locking = 1;
3548 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3549 0, 0);
3550 if (ret < 0)
3551 break;
3552 next:
3553 leaf = path->nodes[0];
3554 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3555 ret = btrfs_next_leaf(rc->extent_root, path);
3556 if (ret != 0)
3557 break;
3558 leaf = path->nodes[0];
3559 }
3560
3561 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3562 if (key.objectid >= last) {
3563 ret = 1;
3564 break;
3565 }
3566
3567 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3568 key.objectid + key.offset <= rc->search_start) {
3569 path->slots[0]++;
3570 goto next;
3571 }
3572
3573 ret = find_first_extent_bit(&rc->processed_blocks,
3574 key.objectid, &start, &end,
3575 EXTENT_DIRTY);
3576
3577 if (ret == 0 && start <= key.objectid) {
3578 btrfs_release_path(path);
3579 rc->search_start = end + 1;
3580 } else {
3581 rc->search_start = key.objectid + key.offset;
3582 memcpy(extent_key, &key, sizeof(key));
3583 return 0;
3584 }
3585 }
3586 btrfs_release_path(path);
3587 return ret;
3588 }
3589
3590 static void set_reloc_control(struct reloc_control *rc)
3591 {
3592 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3593 spin_lock(&fs_info->trans_lock);
3594 fs_info->reloc_ctl = rc;
3595 spin_unlock(&fs_info->trans_lock);
3596 }
3597
3598 static void unset_reloc_control(struct reloc_control *rc)
3599 {
3600 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3601 spin_lock(&fs_info->trans_lock);
3602 fs_info->reloc_ctl = NULL;
3603 spin_unlock(&fs_info->trans_lock);
3604 }
3605
3606 static int check_extent_flags(u64 flags)
3607 {
3608 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3609 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3610 return 1;
3611 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3612 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3613 return 1;
3614 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3615 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3616 return 1;
3617 return 0;
3618 }
3619
3620 static noinline_for_stack
3621 int prepare_to_relocate(struct reloc_control *rc)
3622 {
3623 struct btrfs_trans_handle *trans;
3624 int ret;
3625
3626 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3627 if (!rc->block_rsv)
3628 return -ENOMEM;
3629
3630 /*
3631 * reserve some space for creating reloc trees.
3632 * btrfs_init_reloc_root will use them when there
3633 * is no reservation in transaction handle.
3634 */
3635 ret = btrfs_block_rsv_add(NULL, rc->extent_root, rc->block_rsv,
3636 rc->extent_root->nodesize * 256);
3637 if (ret)
3638 return ret;
3639
3640 rc->block_rsv->refill_used = 1;
3641 btrfs_add_durable_block_rsv(rc->extent_root->fs_info, rc->block_rsv);
3642
3643 memset(&rc->cluster, 0, sizeof(rc->cluster));
3644 rc->search_start = rc->block_group->key.objectid;
3645 rc->extents_found = 0;
3646 rc->nodes_relocated = 0;
3647 rc->merging_rsv_size = 0;
3648
3649 rc->create_reloc_tree = 1;
3650 set_reloc_control(rc);
3651
3652 trans = btrfs_join_transaction(rc->extent_root);
3653 BUG_ON(IS_ERR(trans));
3654 btrfs_commit_transaction(trans, rc->extent_root);
3655 return 0;
3656 }
3657
3658 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3659 {
3660 struct rb_root blocks = RB_ROOT;
3661 struct btrfs_key key;
3662 struct btrfs_trans_handle *trans = NULL;
3663 struct btrfs_path *path;
3664 struct btrfs_extent_item *ei;
3665 unsigned long nr;
3666 u64 flags;
3667 u32 item_size;
3668 int ret;
3669 int err = 0;
3670 int progress = 0;
3671
3672 path = btrfs_alloc_path();
3673 if (!path)
3674 return -ENOMEM;
3675 path->reada = 1;
3676
3677 ret = prepare_to_relocate(rc);
3678 if (ret) {
3679 err = ret;
3680 goto out_free;
3681 }
3682
3683 while (1) {
3684 progress++;
3685 trans = btrfs_start_transaction(rc->extent_root, 0);
3686 BUG_ON(IS_ERR(trans));
3687 restart:
3688 if (update_backref_cache(trans, &rc->backref_cache)) {
3689 btrfs_end_transaction(trans, rc->extent_root);
3690 continue;
3691 }
3692
3693 ret = find_next_extent(trans, rc, path, &key);
3694 if (ret < 0)
3695 err = ret;
3696 if (ret != 0)
3697 break;
3698
3699 rc->extents_found++;
3700
3701 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3702 struct btrfs_extent_item);
3703 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3704 if (item_size >= sizeof(*ei)) {
3705 flags = btrfs_extent_flags(path->nodes[0], ei);
3706 ret = check_extent_flags(flags);
3707 BUG_ON(ret);
3708
3709 } else {
3710 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3711 u64 ref_owner;
3712 int path_change = 0;
3713
3714 BUG_ON(item_size !=
3715 sizeof(struct btrfs_extent_item_v0));
3716 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3717 &path_change);
3718 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3719 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3720 else
3721 flags = BTRFS_EXTENT_FLAG_DATA;
3722
3723 if (path_change) {
3724 btrfs_release_path(path);
3725
3726 path->search_commit_root = 1;
3727 path->skip_locking = 1;
3728 ret = btrfs_search_slot(NULL, rc->extent_root,
3729 &key, path, 0, 0);
3730 if (ret < 0) {
3731 err = ret;
3732 break;
3733 }
3734 BUG_ON(ret > 0);
3735 }
3736 #else
3737 BUG();
3738 #endif
3739 }
3740
3741 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3742 ret = add_tree_block(rc, &key, path, &blocks);
3743 } else if (rc->stage == UPDATE_DATA_PTRS &&
3744 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3745 ret = add_data_references(rc, &key, path, &blocks);
3746 } else {
3747 btrfs_release_path(path);
3748 ret = 0;
3749 }
3750 if (ret < 0) {
3751 err = ret;
3752 break;
3753 }
3754
3755 if (!RB_EMPTY_ROOT(&blocks)) {
3756 ret = relocate_tree_blocks(trans, rc, &blocks);
3757 if (ret < 0) {
3758 if (ret != -EAGAIN) {
3759 err = ret;
3760 break;
3761 }
3762 rc->extents_found--;
3763 rc->search_start = key.objectid;
3764 }
3765 }
3766
3767 ret = btrfs_block_rsv_check(trans, rc->extent_root,
3768 rc->block_rsv, 0, 5);
3769 if (ret < 0) {
3770 if (ret != -EAGAIN) {
3771 err = ret;
3772 WARN_ON(1);
3773 break;
3774 }
3775 rc->commit_transaction = 1;
3776 }
3777
3778 if (rc->commit_transaction) {
3779 rc->commit_transaction = 0;
3780 ret = btrfs_commit_transaction(trans, rc->extent_root);
3781 BUG_ON(ret);
3782 } else {
3783 nr = trans->blocks_used;
3784 btrfs_end_transaction_throttle(trans, rc->extent_root);
3785 btrfs_btree_balance_dirty(rc->extent_root, nr);
3786 }
3787 trans = NULL;
3788
3789 if (rc->stage == MOVE_DATA_EXTENTS &&
3790 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3791 rc->found_file_extent = 1;
3792 ret = relocate_data_extent(rc->data_inode,
3793 &key, &rc->cluster);
3794 if (ret < 0) {
3795 err = ret;
3796 break;
3797 }
3798 }
3799 }
3800 if (trans && progress && err == -ENOSPC) {
3801 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3802 rc->block_group->flags);
3803 if (ret == 0) {
3804 err = 0;
3805 progress = 0;
3806 goto restart;
3807 }
3808 }
3809
3810 btrfs_release_path(path);
3811 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3812 GFP_NOFS);
3813
3814 if (trans) {
3815 nr = trans->blocks_used;
3816 btrfs_end_transaction_throttle(trans, rc->extent_root);
3817 btrfs_btree_balance_dirty(rc->extent_root, nr);
3818 }
3819
3820 if (!err) {
3821 ret = relocate_file_extent_cluster(rc->data_inode,
3822 &rc->cluster);
3823 if (ret < 0)
3824 err = ret;
3825 }
3826
3827 rc->create_reloc_tree = 0;
3828 set_reloc_control(rc);
3829
3830 backref_cache_cleanup(&rc->backref_cache);
3831 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3832
3833 err = prepare_to_merge(rc, err);
3834
3835 merge_reloc_roots(rc);
3836
3837 rc->merge_reloc_tree = 0;
3838 unset_reloc_control(rc);
3839 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3840
3841 /* get rid of pinned extents */
3842 trans = btrfs_join_transaction(rc->extent_root);
3843 if (IS_ERR(trans))
3844 err = PTR_ERR(trans);
3845 else
3846 btrfs_commit_transaction(trans, rc->extent_root);
3847 out_free:
3848 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3849 btrfs_free_path(path);
3850 return err;
3851 }
3852
3853 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3854 struct btrfs_root *root, u64 objectid)
3855 {
3856 struct btrfs_path *path;
3857 struct btrfs_inode_item *item;
3858 struct extent_buffer *leaf;
3859 int ret;
3860
3861 path = btrfs_alloc_path();
3862 if (!path)
3863 return -ENOMEM;
3864
3865 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3866 if (ret)
3867 goto out;
3868
3869 leaf = path->nodes[0];
3870 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3871 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3872 btrfs_set_inode_generation(leaf, item, 1);
3873 btrfs_set_inode_size(leaf, item, 0);
3874 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3875 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3876 BTRFS_INODE_PREALLOC);
3877 btrfs_mark_buffer_dirty(leaf);
3878 btrfs_release_path(path);
3879 out:
3880 btrfs_free_path(path);
3881 return ret;
3882 }
3883
3884 /*
3885 * helper to create inode for data relocation.
3886 * the inode is in data relocation tree and its link count is 0
3887 */
3888 static noinline_for_stack
3889 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3890 struct btrfs_block_group_cache *group)
3891 {
3892 struct inode *inode = NULL;
3893 struct btrfs_trans_handle *trans;
3894 struct btrfs_root *root;
3895 struct btrfs_key key;
3896 unsigned long nr;
3897 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3898 int err = 0;
3899
3900 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3901 if (IS_ERR(root))
3902 return ERR_CAST(root);
3903
3904 trans = btrfs_start_transaction(root, 6);
3905 if (IS_ERR(trans))
3906 return ERR_CAST(trans);
3907
3908 err = btrfs_find_free_objectid(root, &objectid);
3909 if (err)
3910 goto out;
3911
3912 err = __insert_orphan_inode(trans, root, objectid);
3913 BUG_ON(err);
3914
3915 key.objectid = objectid;
3916 key.type = BTRFS_INODE_ITEM_KEY;
3917 key.offset = 0;
3918 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3919 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3920 BTRFS_I(inode)->index_cnt = group->key.objectid;
3921
3922 err = btrfs_orphan_add(trans, inode);
3923 out:
3924 nr = trans->blocks_used;
3925 btrfs_end_transaction(trans, root);
3926 btrfs_btree_balance_dirty(root, nr);
3927 if (err) {
3928 if (inode)
3929 iput(inode);
3930 inode = ERR_PTR(err);
3931 }
3932 return inode;
3933 }
3934
3935 static struct reloc_control *alloc_reloc_control(void)
3936 {
3937 struct reloc_control *rc;
3938
3939 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3940 if (!rc)
3941 return NULL;
3942
3943 INIT_LIST_HEAD(&rc->reloc_roots);
3944 backref_cache_init(&rc->backref_cache);
3945 mapping_tree_init(&rc->reloc_root_tree);
3946 extent_io_tree_init(&rc->processed_blocks, NULL);
3947 return rc;
3948 }
3949
3950 /*
3951 * function to relocate all extents in a block group.
3952 */
3953 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
3954 {
3955 struct btrfs_fs_info *fs_info = extent_root->fs_info;
3956 struct reloc_control *rc;
3957 struct inode *inode;
3958 struct btrfs_path *path;
3959 int ret;
3960 int rw = 0;
3961 int err = 0;
3962
3963 rc = alloc_reloc_control();
3964 if (!rc)
3965 return -ENOMEM;
3966
3967 rc->extent_root = extent_root;
3968
3969 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
3970 BUG_ON(!rc->block_group);
3971
3972 if (!rc->block_group->ro) {
3973 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
3974 if (ret) {
3975 err = ret;
3976 goto out;
3977 }
3978 rw = 1;
3979 }
3980
3981 path = btrfs_alloc_path();
3982 if (!path) {
3983 err = -ENOMEM;
3984 goto out;
3985 }
3986
3987 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
3988 path);
3989 btrfs_free_path(path);
3990
3991 if (!IS_ERR(inode))
3992 ret = delete_block_group_cache(fs_info, inode, 0);
3993 else
3994 ret = PTR_ERR(inode);
3995
3996 if (ret && ret != -ENOENT) {
3997 err = ret;
3998 goto out;
3999 }
4000
4001 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4002 if (IS_ERR(rc->data_inode)) {
4003 err = PTR_ERR(rc->data_inode);
4004 rc->data_inode = NULL;
4005 goto out;
4006 }
4007
4008 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4009 (unsigned long long)rc->block_group->key.objectid,
4010 (unsigned long long)rc->block_group->flags);
4011
4012 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4013 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4014
4015 while (1) {
4016 mutex_lock(&fs_info->cleaner_mutex);
4017
4018 btrfs_clean_old_snapshots(fs_info->tree_root);
4019 ret = relocate_block_group(rc);
4020
4021 mutex_unlock(&fs_info->cleaner_mutex);
4022 if (ret < 0) {
4023 err = ret;
4024 goto out;
4025 }
4026
4027 if (rc->extents_found == 0)
4028 break;
4029
4030 printk(KERN_INFO "btrfs: found %llu extents\n",
4031 (unsigned long long)rc->extents_found);
4032
4033 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4034 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4035 invalidate_mapping_pages(rc->data_inode->i_mapping,
4036 0, -1);
4037 rc->stage = UPDATE_DATA_PTRS;
4038 }
4039 }
4040
4041 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4042 rc->block_group->key.objectid,
4043 rc->block_group->key.objectid +
4044 rc->block_group->key.offset - 1);
4045
4046 WARN_ON(rc->block_group->pinned > 0);
4047 WARN_ON(rc->block_group->reserved > 0);
4048 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4049 out:
4050 if (err && rw)
4051 btrfs_set_block_group_rw(extent_root, rc->block_group);
4052 iput(rc->data_inode);
4053 btrfs_put_block_group(rc->block_group);
4054 kfree(rc);
4055 return err;
4056 }
4057
4058 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4059 {
4060 struct btrfs_trans_handle *trans;
4061 int ret;
4062
4063 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4064 BUG_ON(IS_ERR(trans));
4065
4066 memset(&root->root_item.drop_progress, 0,
4067 sizeof(root->root_item.drop_progress));
4068 root->root_item.drop_level = 0;
4069 btrfs_set_root_refs(&root->root_item, 0);
4070 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4071 &root->root_key, &root->root_item);
4072 BUG_ON(ret);
4073
4074 ret = btrfs_end_transaction(trans, root->fs_info->tree_root);
4075 BUG_ON(ret);
4076 return 0;
4077 }
4078
4079 /*
4080 * recover relocation interrupted by system crash.
4081 *
4082 * this function resumes merging reloc trees with corresponding fs trees.
4083 * this is important for keeping the sharing of tree blocks
4084 */
4085 int btrfs_recover_relocation(struct btrfs_root *root)
4086 {
4087 LIST_HEAD(reloc_roots);
4088 struct btrfs_key key;
4089 struct btrfs_root *fs_root;
4090 struct btrfs_root *reloc_root;
4091 struct btrfs_path *path;
4092 struct extent_buffer *leaf;
4093 struct reloc_control *rc = NULL;
4094 struct btrfs_trans_handle *trans;
4095 int ret;
4096 int err = 0;
4097
4098 path = btrfs_alloc_path();
4099 if (!path)
4100 return -ENOMEM;
4101 path->reada = -1;
4102
4103 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4104 key.type = BTRFS_ROOT_ITEM_KEY;
4105 key.offset = (u64)-1;
4106
4107 while (1) {
4108 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4109 path, 0, 0);
4110 if (ret < 0) {
4111 err = ret;
4112 goto out;
4113 }
4114 if (ret > 0) {
4115 if (path->slots[0] == 0)
4116 break;
4117 path->slots[0]--;
4118 }
4119 leaf = path->nodes[0];
4120 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4121 btrfs_release_path(path);
4122
4123 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4124 key.type != BTRFS_ROOT_ITEM_KEY)
4125 break;
4126
4127 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4128 if (IS_ERR(reloc_root)) {
4129 err = PTR_ERR(reloc_root);
4130 goto out;
4131 }
4132
4133 list_add(&reloc_root->root_list, &reloc_roots);
4134
4135 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4136 fs_root = read_fs_root(root->fs_info,
4137 reloc_root->root_key.offset);
4138 if (IS_ERR(fs_root)) {
4139 ret = PTR_ERR(fs_root);
4140 if (ret != -ENOENT) {
4141 err = ret;
4142 goto out;
4143 }
4144 mark_garbage_root(reloc_root);
4145 }
4146 }
4147
4148 if (key.offset == 0)
4149 break;
4150
4151 key.offset--;
4152 }
4153 btrfs_release_path(path);
4154
4155 if (list_empty(&reloc_roots))
4156 goto out;
4157
4158 rc = alloc_reloc_control();
4159 if (!rc) {
4160 err = -ENOMEM;
4161 goto out;
4162 }
4163
4164 rc->extent_root = root->fs_info->extent_root;
4165
4166 set_reloc_control(rc);
4167
4168 trans = btrfs_join_transaction(rc->extent_root);
4169 if (IS_ERR(trans)) {
4170 unset_reloc_control(rc);
4171 err = PTR_ERR(trans);
4172 goto out_free;
4173 }
4174
4175 rc->merge_reloc_tree = 1;
4176
4177 while (!list_empty(&reloc_roots)) {
4178 reloc_root = list_entry(reloc_roots.next,
4179 struct btrfs_root, root_list);
4180 list_del(&reloc_root->root_list);
4181
4182 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4183 list_add_tail(&reloc_root->root_list,
4184 &rc->reloc_roots);
4185 continue;
4186 }
4187
4188 fs_root = read_fs_root(root->fs_info,
4189 reloc_root->root_key.offset);
4190 BUG_ON(IS_ERR(fs_root));
4191
4192 __add_reloc_root(reloc_root);
4193 fs_root->reloc_root = reloc_root;
4194 }
4195
4196 btrfs_commit_transaction(trans, rc->extent_root);
4197
4198 merge_reloc_roots(rc);
4199
4200 unset_reloc_control(rc);
4201
4202 trans = btrfs_join_transaction(rc->extent_root);
4203 if (IS_ERR(trans))
4204 err = PTR_ERR(trans);
4205 else
4206 btrfs_commit_transaction(trans, rc->extent_root);
4207 out_free:
4208 kfree(rc);
4209 out:
4210 while (!list_empty(&reloc_roots)) {
4211 reloc_root = list_entry(reloc_roots.next,
4212 struct btrfs_root, root_list);
4213 list_del(&reloc_root->root_list);
4214 free_extent_buffer(reloc_root->node);
4215 free_extent_buffer(reloc_root->commit_root);
4216 kfree(reloc_root);
4217 }
4218 btrfs_free_path(path);
4219
4220 if (err == 0) {
4221 /* cleanup orphan inode in data relocation tree */
4222 fs_root = read_fs_root(root->fs_info,
4223 BTRFS_DATA_RELOC_TREE_OBJECTID);
4224 if (IS_ERR(fs_root))
4225 err = PTR_ERR(fs_root);
4226 else
4227 err = btrfs_orphan_cleanup(fs_root);
4228 }
4229 return err;
4230 }
4231
4232 /*
4233 * helper to add ordered checksum for data relocation.
4234 *
4235 * cloning checksum properly handles the nodatasum extents.
4236 * it also saves CPU time to re-calculate the checksum.
4237 */
4238 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4239 {
4240 struct btrfs_ordered_sum *sums;
4241 struct btrfs_sector_sum *sector_sum;
4242 struct btrfs_ordered_extent *ordered;
4243 struct btrfs_root *root = BTRFS_I(inode)->root;
4244 size_t offset;
4245 int ret;
4246 u64 disk_bytenr;
4247 LIST_HEAD(list);
4248
4249 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4250 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4251
4252 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4253 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4254 disk_bytenr + len - 1, &list, 0);
4255
4256 while (!list_empty(&list)) {
4257 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4258 list_del_init(&sums->list);
4259
4260 sector_sum = sums->sums;
4261 sums->bytenr = ordered->start;
4262
4263 offset = 0;
4264 while (offset < sums->len) {
4265 sector_sum->bytenr += ordered->start - disk_bytenr;
4266 sector_sum++;
4267 offset += root->sectorsize;
4268 }
4269
4270 btrfs_add_ordered_sum(inode, ordered, sums);
4271 }
4272 btrfs_put_ordered_extent(ordered);
4273 return ret;
4274 }
4275
4276 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4277 struct btrfs_root *root, struct extent_buffer *buf,
4278 struct extent_buffer *cow)
4279 {
4280 struct reloc_control *rc;
4281 struct backref_node *node;
4282 int first_cow = 0;
4283 int level;
4284 int ret;
4285
4286 rc = root->fs_info->reloc_ctl;
4287 if (!rc)
4288 return;
4289
4290 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4291 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4292
4293 level = btrfs_header_level(buf);
4294 if (btrfs_header_generation(buf) <=
4295 btrfs_root_last_snapshot(&root->root_item))
4296 first_cow = 1;
4297
4298 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4299 rc->create_reloc_tree) {
4300 WARN_ON(!first_cow && level == 0);
4301
4302 node = rc->backref_cache.path[level];
4303 BUG_ON(node->bytenr != buf->start &&
4304 node->new_bytenr != buf->start);
4305
4306 drop_node_buffer(node);
4307 extent_buffer_get(cow);
4308 node->eb = cow;
4309 node->new_bytenr = cow->start;
4310
4311 if (!node->pending) {
4312 list_move_tail(&node->list,
4313 &rc->backref_cache.pending[level]);
4314 node->pending = 1;
4315 }
4316
4317 if (first_cow)
4318 __mark_block_processed(rc, node);
4319
4320 if (first_cow && level > 0)
4321 rc->nodes_relocated += buf->len;
4322 }
4323
4324 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4325 ret = replace_file_extents(trans, rc, root, cow);
4326 BUG_ON(ret);
4327 }
4328 }
4329
4330 /*
4331 * called before creating snapshot. it calculates metadata reservation
4332 * requried for relocating tree blocks in the snapshot
4333 */
4334 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4335 struct btrfs_pending_snapshot *pending,
4336 u64 *bytes_to_reserve)
4337 {
4338 struct btrfs_root *root;
4339 struct reloc_control *rc;
4340
4341 root = pending->root;
4342 if (!root->reloc_root)
4343 return;
4344
4345 rc = root->fs_info->reloc_ctl;
4346 if (!rc->merge_reloc_tree)
4347 return;
4348
4349 root = root->reloc_root;
4350 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4351 /*
4352 * relocation is in the stage of merging trees. the space
4353 * used by merging a reloc tree is twice the size of
4354 * relocated tree nodes in the worst case. half for cowing
4355 * the reloc tree, half for cowing the fs tree. the space
4356 * used by cowing the reloc tree will be freed after the
4357 * tree is dropped. if we create snapshot, cowing the fs
4358 * tree may use more space than it frees. so we need
4359 * reserve extra space.
4360 */
4361 *bytes_to_reserve += rc->nodes_relocated;
4362 }
4363
4364 /*
4365 * called after snapshot is created. migrate block reservation
4366 * and create reloc root for the newly created snapshot
4367 */
4368 void btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4369 struct btrfs_pending_snapshot *pending)
4370 {
4371 struct btrfs_root *root = pending->root;
4372 struct btrfs_root *reloc_root;
4373 struct btrfs_root *new_root;
4374 struct reloc_control *rc;
4375 int ret;
4376
4377 if (!root->reloc_root)
4378 return;
4379
4380 rc = root->fs_info->reloc_ctl;
4381 rc->merging_rsv_size += rc->nodes_relocated;
4382
4383 if (rc->merge_reloc_tree) {
4384 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4385 rc->block_rsv,
4386 rc->nodes_relocated);
4387 BUG_ON(ret);
4388 }
4389
4390 new_root = pending->snap;
4391 reloc_root = create_reloc_root(trans, root->reloc_root,
4392 new_root->root_key.objectid);
4393
4394 __add_reloc_root(reloc_root);
4395 new_root->reloc_root = reloc_root;
4396
4397 if (rc->create_reloc_tree) {
4398 ret = clone_backref_node(trans, rc, root, reloc_root);
4399 BUG_ON(ret);
4400 }
4401 }
Linux kernel - Deliverables
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