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cipso: don't follow a NULL pointer when setsockopt() is called
[linux-2.6/cjktty.git] / fs / btrfs / relocation.c
blob646ee21bb035d9ad8a4b1628e6883544c0603ea6
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97
98 struct backref_cache {
99 /* red black tree of all backref nodes in the cache */
100 struct rb_root rb_root;
101 /* for passing backref nodes to btrfs_reloc_cow_block */
102 struct backref_node *path[BTRFS_MAX_LEVEL];
103 /*
104 * list of blocks that have been cowed but some block
105 * pointers in upper level blocks may not reflect the
106 * new location
107 */
108 struct list_head pending[BTRFS_MAX_LEVEL];
109 /* list of backref nodes with no child node */
110 struct list_head leaves;
111 /* list of blocks that have been cowed in current transaction */
112 struct list_head changed;
113 /* list of detached backref node. */
114 struct list_head detached;
115
116 u64 last_trans;
117
118 int nr_nodes;
119 int nr_edges;
120 };
121
122 /*
123 * map address of tree root to tree
124 */
125 struct mapping_node {
126 struct rb_node rb_node;
127 u64 bytenr;
128 void *data;
129 };
130
131 struct mapping_tree {
132 struct rb_root rb_root;
133 spinlock_t lock;
134 };
135
136 /*
137 * present a tree block to process
138 */
139 struct tree_block {
140 struct rb_node rb_node;
141 u64 bytenr;
142 struct btrfs_key key;
143 unsigned int level:8;
144 unsigned int key_ready:1;
145 };
146
147 #define MAX_EXTENTS 128
148
149 struct file_extent_cluster {
150 u64 start;
151 u64 end;
152 u64 boundary[MAX_EXTENTS];
153 unsigned int nr;
154 };
155
156 struct reloc_control {
157 /* block group to relocate */
158 struct btrfs_block_group_cache *block_group;
159 /* extent tree */
160 struct btrfs_root *extent_root;
161 /* inode for moving data */
162 struct inode *data_inode;
163
164 struct btrfs_block_rsv *block_rsv;
165
166 struct backref_cache backref_cache;
167
168 struct file_extent_cluster cluster;
169 /* tree blocks have been processed */
170 struct extent_io_tree processed_blocks;
171 /* map start of tree root to corresponding reloc tree */
172 struct mapping_tree reloc_root_tree;
173 /* list of reloc trees */
174 struct list_head reloc_roots;
175 /* size of metadata reservation for merging reloc trees */
176 u64 merging_rsv_size;
177 /* size of relocated tree nodes */
178 u64 nodes_relocated;
179
180 u64 search_start;
181 u64 extents_found;
182
183 unsigned int stage:8;
184 unsigned int create_reloc_tree:1;
185 unsigned int merge_reloc_tree:1;
186 unsigned int found_file_extent:1;
187 unsigned int commit_transaction:1;
188 };
189
190 /* stages of data relocation */
191 #define MOVE_DATA_EXTENTS 0
192 #define UPDATE_DATA_PTRS 1
193
194 static void remove_backref_node(struct backref_cache *cache,
195 struct backref_node *node);
196 static void __mark_block_processed(struct reloc_control *rc,
197 struct backref_node *node);
198
199 static void mapping_tree_init(struct mapping_tree *tree)
200 {
201 tree->rb_root = RB_ROOT;
202 spin_lock_init(&tree->lock);
203 }
204
205 static void backref_cache_init(struct backref_cache *cache)
206 {
207 int i;
208 cache->rb_root = RB_ROOT;
209 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
210 INIT_LIST_HEAD(&cache->pending[i]);
211 INIT_LIST_HEAD(&cache->changed);
212 INIT_LIST_HEAD(&cache->detached);
213 INIT_LIST_HEAD(&cache->leaves);
214 }
215
216 static void backref_cache_cleanup(struct backref_cache *cache)
217 {
218 struct backref_node *node;
219 int i;
220
221 while (!list_empty(&cache->detached)) {
222 node = list_entry(cache->detached.next,
223 struct backref_node, list);
224 remove_backref_node(cache, node);
225 }
226
227 while (!list_empty(&cache->leaves)) {
228 node = list_entry(cache->leaves.next,
229 struct backref_node, lower);
230 remove_backref_node(cache, node);
231 }
232
233 cache->last_trans = 0;
234
235 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
236 BUG_ON(!list_empty(&cache->pending[i]));
237 BUG_ON(!list_empty(&cache->changed));
238 BUG_ON(!list_empty(&cache->detached));
239 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
240 BUG_ON(cache->nr_nodes);
241 BUG_ON(cache->nr_edges);
242 }
243
244 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
245 {
246 struct backref_node *node;
247
248 node = kzalloc(sizeof(*node), GFP_NOFS);
249 if (node) {
250 INIT_LIST_HEAD(&node->list);
251 INIT_LIST_HEAD(&node->upper);
252 INIT_LIST_HEAD(&node->lower);
253 RB_CLEAR_NODE(&node->rb_node);
254 cache->nr_nodes++;
255 }
256 return node;
257 }
258
259 static void free_backref_node(struct backref_cache *cache,
260 struct backref_node *node)
261 {
262 if (node) {
263 cache->nr_nodes--;
264 kfree(node);
265 }
266 }
267
268 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
269 {
270 struct backref_edge *edge;
271
272 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 if (edge)
274 cache->nr_edges++;
275 return edge;
276 }
277
278 static void free_backref_edge(struct backref_cache *cache,
279 struct backref_edge *edge)
280 {
281 if (edge) {
282 cache->nr_edges--;
283 kfree(edge);
284 }
285 }
286
287 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
288 struct rb_node *node)
289 {
290 struct rb_node **p = &root->rb_node;
291 struct rb_node *parent = NULL;
292 struct tree_entry *entry;
293
294 while (*p) {
295 parent = *p;
296 entry = rb_entry(parent, struct tree_entry, rb_node);
297
298 if (bytenr < entry->bytenr)
299 p = &(*p)->rb_left;
300 else if (bytenr > entry->bytenr)
301 p = &(*p)->rb_right;
302 else
303 return parent;
304 }
305
306 rb_link_node(node, parent, p);
307 rb_insert_color(node, root);
308 return NULL;
309 }
310
311 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
312 {
313 struct rb_node *n = root->rb_node;
314 struct tree_entry *entry;
315
316 while (n) {
317 entry = rb_entry(n, struct tree_entry, rb_node);
318
319 if (bytenr < entry->bytenr)
320 n = n->rb_left;
321 else if (bytenr > entry->bytenr)
322 n = n->rb_right;
323 else
324 return n;
325 }
326 return NULL;
327 }
328
329 void backref_tree_panic(struct rb_node *rb_node, int errno,
330 u64 bytenr)
331 {
332
333 struct btrfs_fs_info *fs_info = NULL;
334 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
335 rb_node);
336 if (bnode->root)
337 fs_info = bnode->root->fs_info;
338 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
339 "found at offset %llu\n", (unsigned long long)bytenr);
340 }
341
342 /*
343 * walk up backref nodes until reach node presents tree root
344 */
345 static struct backref_node *walk_up_backref(struct backref_node *node,
346 struct backref_edge *edges[],
347 int *index)
348 {
349 struct backref_edge *edge;
350 int idx = *index;
351
352 while (!list_empty(&node->upper)) {
353 edge = list_entry(node->upper.next,
354 struct backref_edge, list[LOWER]);
355 edges[idx++] = edge;
356 node = edge->node[UPPER];
357 }
358 BUG_ON(node->detached);
359 *index = idx;
360 return node;
361 }
362
363 /*
364 * walk down backref nodes to find start of next reference path
365 */
366 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
367 int *index)
368 {
369 struct backref_edge *edge;
370 struct backref_node *lower;
371 int idx = *index;
372
373 while (idx > 0) {
374 edge = edges[idx - 1];
375 lower = edge->node[LOWER];
376 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
377 idx--;
378 continue;
379 }
380 edge = list_entry(edge->list[LOWER].next,
381 struct backref_edge, list[LOWER]);
382 edges[idx - 1] = edge;
383 *index = idx;
384 return edge->node[UPPER];
385 }
386 *index = 0;
387 return NULL;
388 }
389
390 static void unlock_node_buffer(struct backref_node *node)
391 {
392 if (node->locked) {
393 btrfs_tree_unlock(node->eb);
394 node->locked = 0;
395 }
396 }
397
398 static void drop_node_buffer(struct backref_node *node)
399 {
400 if (node->eb) {
401 unlock_node_buffer(node);
402 free_extent_buffer(node->eb);
403 node->eb = NULL;
404 }
405 }
406
407 static void drop_backref_node(struct backref_cache *tree,
408 struct backref_node *node)
409 {
410 BUG_ON(!list_empty(&node->upper));
411
412 drop_node_buffer(node);
413 list_del(&node->list);
414 list_del(&node->lower);
415 if (!RB_EMPTY_NODE(&node->rb_node))
416 rb_erase(&node->rb_node, &tree->rb_root);
417 free_backref_node(tree, node);
418 }
419
420 /*
421 * remove a backref node from the backref cache
422 */
423 static void remove_backref_node(struct backref_cache *cache,
424 struct backref_node *node)
425 {
426 struct backref_node *upper;
427 struct backref_edge *edge;
428
429 if (!node)
430 return;
431
432 BUG_ON(!node->lowest && !node->detached);
433 while (!list_empty(&node->upper)) {
434 edge = list_entry(node->upper.next, struct backref_edge,
435 list[LOWER]);
436 upper = edge->node[UPPER];
437 list_del(&edge->list[LOWER]);
438 list_del(&edge->list[UPPER]);
439 free_backref_edge(cache, edge);
440
441 if (RB_EMPTY_NODE(&upper->rb_node)) {
442 BUG_ON(!list_empty(&node->upper));
443 drop_backref_node(cache, node);
444 node = upper;
445 node->lowest = 1;
446 continue;
447 }
448 /*
449 * add the node to leaf node list if no other
450 * child block cached.
451 */
452 if (list_empty(&upper->lower)) {
453 list_add_tail(&upper->lower, &cache->leaves);
454 upper->lowest = 1;
455 }
456 }
457
458 drop_backref_node(cache, node);
459 }
460
461 static void update_backref_node(struct backref_cache *cache,
462 struct backref_node *node, u64 bytenr)
463 {
464 struct rb_node *rb_node;
465 rb_erase(&node->rb_node, &cache->rb_root);
466 node->bytenr = bytenr;
467 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
468 if (rb_node)
469 backref_tree_panic(rb_node, -EEXIST, bytenr);
470 }
471
472 /*
473 * update backref cache after a transaction commit
474 */
475 static int update_backref_cache(struct btrfs_trans_handle *trans,
476 struct backref_cache *cache)
477 {
478 struct backref_node *node;
479 int level = 0;
480
481 if (cache->last_trans == 0) {
482 cache->last_trans = trans->transid;
483 return 0;
484 }
485
486 if (cache->last_trans == trans->transid)
487 return 0;
488
489 /*
490 * detached nodes are used to avoid unnecessary backref
491 * lookup. transaction commit changes the extent tree.
492 * so the detached nodes are no longer useful.
493 */
494 while (!list_empty(&cache->detached)) {
495 node = list_entry(cache->detached.next,
496 struct backref_node, list);
497 remove_backref_node(cache, node);
498 }
499
500 while (!list_empty(&cache->changed)) {
501 node = list_entry(cache->changed.next,
502 struct backref_node, list);
503 list_del_init(&node->list);
504 BUG_ON(node->pending);
505 update_backref_node(cache, node, node->new_bytenr);
506 }
507
508 /*
509 * some nodes can be left in the pending list if there were
510 * errors during processing the pending nodes.
511 */
512 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
513 list_for_each_entry(node, &cache->pending[level], list) {
514 BUG_ON(!node->pending);
515 if (node->bytenr == node->new_bytenr)
516 continue;
517 update_backref_node(cache, node, node->new_bytenr);
518 }
519 }
520
521 cache->last_trans = 0;
522 return 1;
523 }
524
525
526 static int should_ignore_root(struct btrfs_root *root)
527 {
528 struct btrfs_root *reloc_root;
529
530 if (!root->ref_cows)
531 return 0;
532
533 reloc_root = root->reloc_root;
534 if (!reloc_root)
535 return 0;
536
537 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
538 root->fs_info->running_transaction->transid - 1)
539 return 0;
540 /*
541 * if there is reloc tree and it was created in previous
542 * transaction backref lookup can find the reloc tree,
543 * so backref node for the fs tree root is useless for
544 * relocation.
545 */
546 return 1;
547 }
548 /*
549 * find reloc tree by address of tree root
550 */
551 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
552 u64 bytenr)
553 {
554 struct rb_node *rb_node;
555 struct mapping_node *node;
556 struct btrfs_root *root = NULL;
557
558 spin_lock(&rc->reloc_root_tree.lock);
559 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
560 if (rb_node) {
561 node = rb_entry(rb_node, struct mapping_node, rb_node);
562 root = (struct btrfs_root *)node->data;
563 }
564 spin_unlock(&rc->reloc_root_tree.lock);
565 return root;
566 }
567
568 static int is_cowonly_root(u64 root_objectid)
569 {
570 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
571 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
572 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
573 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
574 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
575 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
576 return 1;
577 return 0;
578 }
579
580 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
581 u64 root_objectid)
582 {
583 struct btrfs_key key;
584
585 key.objectid = root_objectid;
586 key.type = BTRFS_ROOT_ITEM_KEY;
587 if (is_cowonly_root(root_objectid))
588 key.offset = 0;
589 else
590 key.offset = (u64)-1;
591
592 return btrfs_read_fs_root_no_name(fs_info, &key);
593 }
594
595 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
596 static noinline_for_stack
597 struct btrfs_root *find_tree_root(struct reloc_control *rc,
598 struct extent_buffer *leaf,
599 struct btrfs_extent_ref_v0 *ref0)
600 {
601 struct btrfs_root *root;
602 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
603 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
604
605 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
606
607 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
608 BUG_ON(IS_ERR(root));
609
610 if (root->ref_cows &&
611 generation != btrfs_root_generation(&root->root_item))
612 return NULL;
613
614 return root;
615 }
616 #endif
617
618 static noinline_for_stack
619 int find_inline_backref(struct extent_buffer *leaf, int slot,
620 unsigned long *ptr, unsigned long *end)
621 {
622 struct btrfs_extent_item *ei;
623 struct btrfs_tree_block_info *bi;
624 u32 item_size;
625
626 item_size = btrfs_item_size_nr(leaf, slot);
627 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
628 if (item_size < sizeof(*ei)) {
629 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
630 return 1;
631 }
632 #endif
633 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
634 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
635 BTRFS_EXTENT_FLAG_TREE_BLOCK));
636
637 if (item_size <= sizeof(*ei) + sizeof(*bi)) {
638 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
639 return 1;
640 }
641
642 bi = (struct btrfs_tree_block_info *)(ei + 1);
643 *ptr = (unsigned long)(bi + 1);
644 *end = (unsigned long)ei + item_size;
645 return 0;
646 }
647
648 /*
649 * build backref tree for a given tree block. root of the backref tree
650 * corresponds the tree block, leaves of the backref tree correspond
651 * roots of b-trees that reference the tree block.
652 *
653 * the basic idea of this function is check backrefs of a given block
654 * to find upper level blocks that refernece the block, and then check
655 * bakcrefs of these upper level blocks recursively. the recursion stop
656 * when tree root is reached or backrefs for the block is cached.
657 *
658 * NOTE: if we find backrefs for a block are cached, we know backrefs
659 * for all upper level blocks that directly/indirectly reference the
660 * block are also cached.
661 */
662 static noinline_for_stack
663 struct backref_node *build_backref_tree(struct reloc_control *rc,
664 struct btrfs_key *node_key,
665 int level, u64 bytenr)
666 {
667 struct backref_cache *cache = &rc->backref_cache;
668 struct btrfs_path *path1;
669 struct btrfs_path *path2;
670 struct extent_buffer *eb;
671 struct btrfs_root *root;
672 struct backref_node *cur;
673 struct backref_node *upper;
674 struct backref_node *lower;
675 struct backref_node *node = NULL;
676 struct backref_node *exist = NULL;
677 struct backref_edge *edge;
678 struct rb_node *rb_node;
679 struct btrfs_key key;
680 unsigned long end;
681 unsigned long ptr;
682 LIST_HEAD(list);
683 LIST_HEAD(useless);
684 int cowonly;
685 int ret;
686 int err = 0;
687
688 path1 = btrfs_alloc_path();
689 path2 = btrfs_alloc_path();
690 if (!path1 || !path2) {
691 err = -ENOMEM;
692 goto out;
693 }
694 path1->reada = 1;
695 path2->reada = 2;
696
697 node = alloc_backref_node(cache);
698 if (!node) {
699 err = -ENOMEM;
700 goto out;
701 }
702
703 node->bytenr = bytenr;
704 node->level = level;
705 node->lowest = 1;
706 cur = node;
707 again:
708 end = 0;
709 ptr = 0;
710 key.objectid = cur->bytenr;
711 key.type = BTRFS_EXTENT_ITEM_KEY;
712 key.offset = (u64)-1;
713
714 path1->search_commit_root = 1;
715 path1->skip_locking = 1;
716 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
717 0, 0);
718 if (ret < 0) {
719 err = ret;
720 goto out;
721 }
722 BUG_ON(!ret || !path1->slots[0]);
723
724 path1->slots[0]--;
725
726 WARN_ON(cur->checked);
727 if (!list_empty(&cur->upper)) {
728 /*
729 * the backref was added previously when processing
730 * backref of type BTRFS_TREE_BLOCK_REF_KEY
731 */
732 BUG_ON(!list_is_singular(&cur->upper));
733 edge = list_entry(cur->upper.next, struct backref_edge,
734 list[LOWER]);
735 BUG_ON(!list_empty(&edge->list[UPPER]));
736 exist = edge->node[UPPER];
737 /*
738 * add the upper level block to pending list if we need
739 * check its backrefs
740 */
741 if (!exist->checked)
742 list_add_tail(&edge->list[UPPER], &list);
743 } else {
744 exist = NULL;
745 }
746
747 while (1) {
748 cond_resched();
749 eb = path1->nodes[0];
750
751 if (ptr >= end) {
752 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
753 ret = btrfs_next_leaf(rc->extent_root, path1);
754 if (ret < 0) {
755 err = ret;
756 goto out;
757 }
758 if (ret > 0)
759 break;
760 eb = path1->nodes[0];
761 }
762
763 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
764 if (key.objectid != cur->bytenr) {
765 WARN_ON(exist);
766 break;
767 }
768
769 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
770 ret = find_inline_backref(eb, path1->slots[0],
771 &ptr, &end);
772 if (ret)
773 goto next;
774 }
775 }
776
777 if (ptr < end) {
778 /* update key for inline back ref */
779 struct btrfs_extent_inline_ref *iref;
780 iref = (struct btrfs_extent_inline_ref *)ptr;
781 key.type = btrfs_extent_inline_ref_type(eb, iref);
782 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
783 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
784 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
785 }
786
787 if (exist &&
788 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
789 exist->owner == key.offset) ||
790 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
791 exist->bytenr == key.offset))) {
792 exist = NULL;
793 goto next;
794 }
795
796 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
797 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
798 key.type == BTRFS_EXTENT_REF_V0_KEY) {
799 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
800 struct btrfs_extent_ref_v0 *ref0;
801 ref0 = btrfs_item_ptr(eb, path1->slots[0],
802 struct btrfs_extent_ref_v0);
803 if (key.objectid == key.offset) {
804 root = find_tree_root(rc, eb, ref0);
805 if (root && !should_ignore_root(root))
806 cur->root = root;
807 else
808 list_add(&cur->list, &useless);
809 break;
810 }
811 if (is_cowonly_root(btrfs_ref_root_v0(eb,
812 ref0)))
813 cur->cowonly = 1;
814 }
815 #else
816 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
818 #endif
819 if (key.objectid == key.offset) {
820 /*
821 * only root blocks of reloc trees use
822 * backref of this type.
823 */
824 root = find_reloc_root(rc, cur->bytenr);
825 BUG_ON(!root);
826 cur->root = root;
827 break;
828 }
829
830 edge = alloc_backref_edge(cache);
831 if (!edge) {
832 err = -ENOMEM;
833 goto out;
834 }
835 rb_node = tree_search(&cache->rb_root, key.offset);
836 if (!rb_node) {
837 upper = alloc_backref_node(cache);
838 if (!upper) {
839 free_backref_edge(cache, edge);
840 err = -ENOMEM;
841 goto out;
842 }
843 upper->bytenr = key.offset;
844 upper->level = cur->level + 1;
845 /*
846 * backrefs for the upper level block isn't
847 * cached, add the block to pending list
848 */
849 list_add_tail(&edge->list[UPPER], &list);
850 } else {
851 upper = rb_entry(rb_node, struct backref_node,
852 rb_node);
853 BUG_ON(!upper->checked);
854 INIT_LIST_HEAD(&edge->list[UPPER]);
855 }
856 list_add_tail(&edge->list[LOWER], &cur->upper);
857 edge->node[LOWER] = cur;
858 edge->node[UPPER] = upper;
859
860 goto next;
861 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
862 goto next;
863 }
864
865 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
866 root = read_fs_root(rc->extent_root->fs_info, key.offset);
867 if (IS_ERR(root)) {
868 err = PTR_ERR(root);
869 goto out;
870 }
871
872 if (!root->ref_cows)
873 cur->cowonly = 1;
874
875 if (btrfs_root_level(&root->root_item) == cur->level) {
876 /* tree root */
877 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
878 cur->bytenr);
879 if (should_ignore_root(root))
880 list_add(&cur->list, &useless);
881 else
882 cur->root = root;
883 break;
884 }
885
886 level = cur->level + 1;
887
888 /*
889 * searching the tree to find upper level blocks
890 * reference the block.
891 */
892 path2->search_commit_root = 1;
893 path2->skip_locking = 1;
894 path2->lowest_level = level;
895 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
896 path2->lowest_level = 0;
897 if (ret < 0) {
898 err = ret;
899 goto out;
900 }
901 if (ret > 0 && path2->slots[level] > 0)
902 path2->slots[level]--;
903
904 eb = path2->nodes[level];
905 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
906 cur->bytenr);
907
908 lower = cur;
909 for (; level < BTRFS_MAX_LEVEL; level++) {
910 if (!path2->nodes[level]) {
911 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
912 lower->bytenr);
913 if (should_ignore_root(root))
914 list_add(&lower->list, &useless);
915 else
916 lower->root = root;
917 break;
918 }
919
920 edge = alloc_backref_edge(cache);
921 if (!edge) {
922 err = -ENOMEM;
923 goto out;
924 }
925
926 eb = path2->nodes[level];
927 rb_node = tree_search(&cache->rb_root, eb->start);
928 if (!rb_node) {
929 upper = alloc_backref_node(cache);
930 if (!upper) {
931 free_backref_edge(cache, edge);
932 err = -ENOMEM;
933 goto out;
934 }
935 upper->bytenr = eb->start;
936 upper->owner = btrfs_header_owner(eb);
937 upper->level = lower->level + 1;
938 if (!root->ref_cows)
939 upper->cowonly = 1;
940
941 /*
942 * if we know the block isn't shared
943 * we can void checking its backrefs.
944 */
945 if (btrfs_block_can_be_shared(root, eb))
946 upper->checked = 0;
947 else
948 upper->checked = 1;
949
950 /*
951 * add the block to pending list if we
952 * need check its backrefs. only block
953 * at 'cur->level + 1' is added to the
954 * tail of pending list. this guarantees
955 * we check backrefs from lower level
956 * blocks to upper level blocks.
957 */
958 if (!upper->checked &&
959 level == cur->level + 1) {
960 list_add_tail(&edge->list[UPPER],
961 &list);
962 } else
963 INIT_LIST_HEAD(&edge->list[UPPER]);
964 } else {
965 upper = rb_entry(rb_node, struct backref_node,
966 rb_node);
967 BUG_ON(!upper->checked);
968 INIT_LIST_HEAD(&edge->list[UPPER]);
969 if (!upper->owner)
970 upper->owner = btrfs_header_owner(eb);
971 }
972 list_add_tail(&edge->list[LOWER], &lower->upper);
973 edge->node[LOWER] = lower;
974 edge->node[UPPER] = upper;
975
976 if (rb_node)
977 break;
978 lower = upper;
979 upper = NULL;
980 }
981 btrfs_release_path(path2);
982 next:
983 if (ptr < end) {
984 ptr += btrfs_extent_inline_ref_size(key.type);
985 if (ptr >= end) {
986 WARN_ON(ptr > end);
987 ptr = 0;
988 end = 0;
989 }
990 }
991 if (ptr >= end)
992 path1->slots[0]++;
993 }
994 btrfs_release_path(path1);
995
996 cur->checked = 1;
997 WARN_ON(exist);
998
999 /* the pending list isn't empty, take the first block to process */
1000 if (!list_empty(&list)) {
1001 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1002 list_del_init(&edge->list[UPPER]);
1003 cur = edge->node[UPPER];
1004 goto again;
1005 }
1006
1007 /*
1008 * everything goes well, connect backref nodes and insert backref nodes
1009 * into the cache.
1010 */
1011 BUG_ON(!node->checked);
1012 cowonly = node->cowonly;
1013 if (!cowonly) {
1014 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1015 &node->rb_node);
1016 if (rb_node)
1017 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1018 list_add_tail(&node->lower, &cache->leaves);
1019 }
1020
1021 list_for_each_entry(edge, &node->upper, list[LOWER])
1022 list_add_tail(&edge->list[UPPER], &list);
1023
1024 while (!list_empty(&list)) {
1025 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1026 list_del_init(&edge->list[UPPER]);
1027 upper = edge->node[UPPER];
1028 if (upper->detached) {
1029 list_del(&edge->list[LOWER]);
1030 lower = edge->node[LOWER];
1031 free_backref_edge(cache, edge);
1032 if (list_empty(&lower->upper))
1033 list_add(&lower->list, &useless);
1034 continue;
1035 }
1036
1037 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1038 if (upper->lowest) {
1039 list_del_init(&upper->lower);
1040 upper->lowest = 0;
1041 }
1042
1043 list_add_tail(&edge->list[UPPER], &upper->lower);
1044 continue;
1045 }
1046
1047 BUG_ON(!upper->checked);
1048 BUG_ON(cowonly != upper->cowonly);
1049 if (!cowonly) {
1050 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1051 &upper->rb_node);
1052 if (rb_node)
1053 backref_tree_panic(rb_node, -EEXIST,
1054 upper->bytenr);
1055 }
1056
1057 list_add_tail(&edge->list[UPPER], &upper->lower);
1058
1059 list_for_each_entry(edge, &upper->upper, list[LOWER])
1060 list_add_tail(&edge->list[UPPER], &list);
1061 }
1062 /*
1063 * process useless backref nodes. backref nodes for tree leaves
1064 * are deleted from the cache. backref nodes for upper level
1065 * tree blocks are left in the cache to avoid unnecessary backref
1066 * lookup.
1067 */
1068 while (!list_empty(&useless)) {
1069 upper = list_entry(useless.next, struct backref_node, list);
1070 list_del_init(&upper->list);
1071 BUG_ON(!list_empty(&upper->upper));
1072 if (upper == node)
1073 node = NULL;
1074 if (upper->lowest) {
1075 list_del_init(&upper->lower);
1076 upper->lowest = 0;
1077 }
1078 while (!list_empty(&upper->lower)) {
1079 edge = list_entry(upper->lower.next,
1080 struct backref_edge, list[UPPER]);
1081 list_del(&edge->list[UPPER]);
1082 list_del(&edge->list[LOWER]);
1083 lower = edge->node[LOWER];
1084 free_backref_edge(cache, edge);
1085
1086 if (list_empty(&lower->upper))
1087 list_add(&lower->list, &useless);
1088 }
1089 __mark_block_processed(rc, upper);
1090 if (upper->level > 0) {
1091 list_add(&upper->list, &cache->detached);
1092 upper->detached = 1;
1093 } else {
1094 rb_erase(&upper->rb_node, &cache->rb_root);
1095 free_backref_node(cache, upper);
1096 }
1097 }
1098 out:
1099 btrfs_free_path(path1);
1100 btrfs_free_path(path2);
1101 if (err) {
1102 while (!list_empty(&useless)) {
1103 lower = list_entry(useless.next,
1104 struct backref_node, upper);
1105 list_del_init(&lower->upper);
1106 }
1107 upper = node;
1108 INIT_LIST_HEAD(&list);
1109 while (upper) {
1110 if (RB_EMPTY_NODE(&upper->rb_node)) {
1111 list_splice_tail(&upper->upper, &list);
1112 free_backref_node(cache, upper);
1113 }
1114
1115 if (list_empty(&list))
1116 break;
1117
1118 edge = list_entry(list.next, struct backref_edge,
1119 list[LOWER]);
1120 list_del(&edge->list[LOWER]);
1121 upper = edge->node[UPPER];
1122 free_backref_edge(cache, edge);
1123 }
1124 return ERR_PTR(err);
1125 }
1126 BUG_ON(node && node->detached);
1127 return node;
1128 }
1129
1130 /*
1131 * helper to add backref node for the newly created snapshot.
1132 * the backref node is created by cloning backref node that
1133 * corresponds to root of source tree
1134 */
1135 static int clone_backref_node(struct btrfs_trans_handle *trans,
1136 struct reloc_control *rc,
1137 struct btrfs_root *src,
1138 struct btrfs_root *dest)
1139 {
1140 struct btrfs_root *reloc_root = src->reloc_root;
1141 struct backref_cache *cache = &rc->backref_cache;
1142 struct backref_node *node = NULL;
1143 struct backref_node *new_node;
1144 struct backref_edge *edge;
1145 struct backref_edge *new_edge;
1146 struct rb_node *rb_node;
1147
1148 if (cache->last_trans > 0)
1149 update_backref_cache(trans, cache);
1150
1151 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1152 if (rb_node) {
1153 node = rb_entry(rb_node, struct backref_node, rb_node);
1154 if (node->detached)
1155 node = NULL;
1156 else
1157 BUG_ON(node->new_bytenr != reloc_root->node->start);
1158 }
1159
1160 if (!node) {
1161 rb_node = tree_search(&cache->rb_root,
1162 reloc_root->commit_root->start);
1163 if (rb_node) {
1164 node = rb_entry(rb_node, struct backref_node,
1165 rb_node);
1166 BUG_ON(node->detached);
1167 }
1168 }
1169
1170 if (!node)
1171 return 0;
1172
1173 new_node = alloc_backref_node(cache);
1174 if (!new_node)
1175 return -ENOMEM;
1176
1177 new_node->bytenr = dest->node->start;
1178 new_node->level = node->level;
1179 new_node->lowest = node->lowest;
1180 new_node->checked = 1;
1181 new_node->root = dest;
1182
1183 if (!node->lowest) {
1184 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1185 new_edge = alloc_backref_edge(cache);
1186 if (!new_edge)
1187 goto fail;
1188
1189 new_edge->node[UPPER] = new_node;
1190 new_edge->node[LOWER] = edge->node[LOWER];
1191 list_add_tail(&new_edge->list[UPPER],
1192 &new_node->lower);
1193 }
1194 } else {
1195 list_add_tail(&new_node->lower, &cache->leaves);
1196 }
1197
1198 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1199 &new_node->rb_node);
1200 if (rb_node)
1201 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1202
1203 if (!new_node->lowest) {
1204 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1205 list_add_tail(&new_edge->list[LOWER],
1206 &new_edge->node[LOWER]->upper);
1207 }
1208 }
1209 return 0;
1210 fail:
1211 while (!list_empty(&new_node->lower)) {
1212 new_edge = list_entry(new_node->lower.next,
1213 struct backref_edge, list[UPPER]);
1214 list_del(&new_edge->list[UPPER]);
1215 free_backref_edge(cache, new_edge);
1216 }
1217 free_backref_node(cache, new_node);
1218 return -ENOMEM;
1219 }
1220
1221 /*
1222 * helper to add 'address of tree root -> reloc tree' mapping
1223 */
1224 static int __must_check __add_reloc_root(struct btrfs_root *root)
1225 {
1226 struct rb_node *rb_node;
1227 struct mapping_node *node;
1228 struct reloc_control *rc = root->fs_info->reloc_ctl;
1229
1230 node = kmalloc(sizeof(*node), GFP_NOFS);
1231 if (!node)
1232 return -ENOMEM;
1233
1234 node->bytenr = root->node->start;
1235 node->data = root;
1236
1237 spin_lock(&rc->reloc_root_tree.lock);
1238 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1239 node->bytenr, &node->rb_node);
1240 spin_unlock(&rc->reloc_root_tree.lock);
1241 if (rb_node) {
1242 kfree(node);
1243 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1244 "for start=%llu while inserting into relocation "
1245 "tree\n");
1246 }
1247
1248 list_add_tail(&root->root_list, &rc->reloc_roots);
1249 return 0;
1250 }
1251
1252 /*
1253 * helper to update/delete the 'address of tree root -> reloc tree'
1254 * mapping
1255 */
1256 static int __update_reloc_root(struct btrfs_root *root, int del)
1257 {
1258 struct rb_node *rb_node;
1259 struct mapping_node *node = NULL;
1260 struct reloc_control *rc = root->fs_info->reloc_ctl;
1261
1262 spin_lock(&rc->reloc_root_tree.lock);
1263 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1264 root->commit_root->start);
1265 if (rb_node) {
1266 node = rb_entry(rb_node, struct mapping_node, rb_node);
1267 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1268 }
1269 spin_unlock(&rc->reloc_root_tree.lock);
1270
1271 BUG_ON((struct btrfs_root *)node->data != root);
1272
1273 if (!del) {
1274 spin_lock(&rc->reloc_root_tree.lock);
1275 node->bytenr = root->node->start;
1276 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1277 node->bytenr, &node->rb_node);
1278 spin_unlock(&rc->reloc_root_tree.lock);
1279 if (rb_node)
1280 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1281 } else {
1282 spin_lock(&root->fs_info->trans_lock);
1283 list_del_init(&root->root_list);
1284 spin_unlock(&root->fs_info->trans_lock);
1285 kfree(node);
1286 }
1287 return 0;
1288 }
1289
1290 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1291 struct btrfs_root *root, u64 objectid)
1292 {
1293 struct btrfs_root *reloc_root;
1294 struct extent_buffer *eb;
1295 struct btrfs_root_item *root_item;
1296 struct btrfs_key root_key;
1297 int ret;
1298
1299 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1300 BUG_ON(!root_item);
1301
1302 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1303 root_key.type = BTRFS_ROOT_ITEM_KEY;
1304 root_key.offset = objectid;
1305
1306 if (root->root_key.objectid == objectid) {
1307 /* called by btrfs_init_reloc_root */
1308 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1309 BTRFS_TREE_RELOC_OBJECTID);
1310 BUG_ON(ret);
1311
1312 btrfs_set_root_last_snapshot(&root->root_item,
1313 trans->transid - 1);
1314 } else {
1315 /*
1316 * called by btrfs_reloc_post_snapshot_hook.
1317 * the source tree is a reloc tree, all tree blocks
1318 * modified after it was created have RELOC flag
1319 * set in their headers. so it's OK to not update
1320 * the 'last_snapshot'.
1321 */
1322 ret = btrfs_copy_root(trans, root, root->node, &eb,
1323 BTRFS_TREE_RELOC_OBJECTID);
1324 BUG_ON(ret);
1325 }
1326
1327 memcpy(root_item, &root->root_item, sizeof(*root_item));
1328 btrfs_set_root_bytenr(root_item, eb->start);
1329 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1330 btrfs_set_root_generation(root_item, trans->transid);
1331
1332 if (root->root_key.objectid == objectid) {
1333 btrfs_set_root_refs(root_item, 0);
1334 memset(&root_item->drop_progress, 0,
1335 sizeof(struct btrfs_disk_key));
1336 root_item->drop_level = 0;
1337 }
1338
1339 btrfs_tree_unlock(eb);
1340 free_extent_buffer(eb);
1341
1342 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1343 &root_key, root_item);
1344 BUG_ON(ret);
1345 kfree(root_item);
1346
1347 reloc_root = btrfs_read_fs_root_no_radix(root->fs_info->tree_root,
1348 &root_key);
1349 BUG_ON(IS_ERR(reloc_root));
1350 reloc_root->last_trans = trans->transid;
1351 return reloc_root;
1352 }
1353
1354 /*
1355 * create reloc tree for a given fs tree. reloc tree is just a
1356 * snapshot of the fs tree with special root objectid.
1357 */
1358 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1359 struct btrfs_root *root)
1360 {
1361 struct btrfs_root *reloc_root;
1362 struct reloc_control *rc = root->fs_info->reloc_ctl;
1363 int clear_rsv = 0;
1364 int ret;
1365
1366 if (root->reloc_root) {
1367 reloc_root = root->reloc_root;
1368 reloc_root->last_trans = trans->transid;
1369 return 0;
1370 }
1371
1372 if (!rc || !rc->create_reloc_tree ||
1373 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1374 return 0;
1375
1376 if (!trans->block_rsv) {
1377 trans->block_rsv = rc->block_rsv;
1378 clear_rsv = 1;
1379 }
1380 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1381 if (clear_rsv)
1382 trans->block_rsv = NULL;
1383
1384 ret = __add_reloc_root(reloc_root);
1385 BUG_ON(ret < 0);
1386 root->reloc_root = reloc_root;
1387 return 0;
1388 }
1389
1390 /*
1391 * update root item of reloc tree
1392 */
1393 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1394 struct btrfs_root *root)
1395 {
1396 struct btrfs_root *reloc_root;
1397 struct btrfs_root_item *root_item;
1398 int del = 0;
1399 int ret;
1400
1401 if (!root->reloc_root)
1402 goto out;
1403
1404 reloc_root = root->reloc_root;
1405 root_item = &reloc_root->root_item;
1406
1407 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1408 btrfs_root_refs(root_item) == 0) {
1409 root->reloc_root = NULL;
1410 del = 1;
1411 }
1412
1413 __update_reloc_root(reloc_root, del);
1414
1415 if (reloc_root->commit_root != reloc_root->node) {
1416 btrfs_set_root_node(root_item, reloc_root->node);
1417 free_extent_buffer(reloc_root->commit_root);
1418 reloc_root->commit_root = btrfs_root_node(reloc_root);
1419 }
1420
1421 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1422 &reloc_root->root_key, root_item);
1423 BUG_ON(ret);
1424
1425 out:
1426 return 0;
1427 }
1428
1429 /*
1430 * helper to find first cached inode with inode number >= objectid
1431 * in a subvolume
1432 */
1433 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1434 {
1435 struct rb_node *node;
1436 struct rb_node *prev;
1437 struct btrfs_inode *entry;
1438 struct inode *inode;
1439
1440 spin_lock(&root->inode_lock);
1441 again:
1442 node = root->inode_tree.rb_node;
1443 prev = NULL;
1444 while (node) {
1445 prev = node;
1446 entry = rb_entry(node, struct btrfs_inode, rb_node);
1447
1448 if (objectid < btrfs_ino(&entry->vfs_inode))
1449 node = node->rb_left;
1450 else if (objectid > btrfs_ino(&entry->vfs_inode))
1451 node = node->rb_right;
1452 else
1453 break;
1454 }
1455 if (!node) {
1456 while (prev) {
1457 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1458 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1459 node = prev;
1460 break;
1461 }
1462 prev = rb_next(prev);
1463 }
1464 }
1465 while (node) {
1466 entry = rb_entry(node, struct btrfs_inode, rb_node);
1467 inode = igrab(&entry->vfs_inode);
1468 if (inode) {
1469 spin_unlock(&root->inode_lock);
1470 return inode;
1471 }
1472
1473 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1474 if (cond_resched_lock(&root->inode_lock))
1475 goto again;
1476
1477 node = rb_next(node);
1478 }
1479 spin_unlock(&root->inode_lock);
1480 return NULL;
1481 }
1482
1483 static int in_block_group(u64 bytenr,
1484 struct btrfs_block_group_cache *block_group)
1485 {
1486 if (bytenr >= block_group->key.objectid &&
1487 bytenr < block_group->key.objectid + block_group->key.offset)
1488 return 1;
1489 return 0;
1490 }
1491
1492 /*
1493 * get new location of data
1494 */
1495 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1496 u64 bytenr, u64 num_bytes)
1497 {
1498 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1499 struct btrfs_path *path;
1500 struct btrfs_file_extent_item *fi;
1501 struct extent_buffer *leaf;
1502 int ret;
1503
1504 path = btrfs_alloc_path();
1505 if (!path)
1506 return -ENOMEM;
1507
1508 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1509 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1510 bytenr, 0);
1511 if (ret < 0)
1512 goto out;
1513 if (ret > 0) {
1514 ret = -ENOENT;
1515 goto out;
1516 }
1517
1518 leaf = path->nodes[0];
1519 fi = btrfs_item_ptr(leaf, path->slots[0],
1520 struct btrfs_file_extent_item);
1521
1522 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1523 btrfs_file_extent_compression(leaf, fi) ||
1524 btrfs_file_extent_encryption(leaf, fi) ||
1525 btrfs_file_extent_other_encoding(leaf, fi));
1526
1527 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1528 ret = 1;
1529 goto out;
1530 }
1531
1532 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1533 ret = 0;
1534 out:
1535 btrfs_free_path(path);
1536 return ret;
1537 }
1538
1539 /*
1540 * update file extent items in the tree leaf to point to
1541 * the new locations.
1542 */
1543 static noinline_for_stack
1544 int replace_file_extents(struct btrfs_trans_handle *trans,
1545 struct reloc_control *rc,
1546 struct btrfs_root *root,
1547 struct extent_buffer *leaf)
1548 {
1549 struct btrfs_key key;
1550 struct btrfs_file_extent_item *fi;
1551 struct inode *inode = NULL;
1552 u64 parent;
1553 u64 bytenr;
1554 u64 new_bytenr = 0;
1555 u64 num_bytes;
1556 u64 end;
1557 u32 nritems;
1558 u32 i;
1559 int ret;
1560 int first = 1;
1561 int dirty = 0;
1562
1563 if (rc->stage != UPDATE_DATA_PTRS)
1564 return 0;
1565
1566 /* reloc trees always use full backref */
1567 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1568 parent = leaf->start;
1569 else
1570 parent = 0;
1571
1572 nritems = btrfs_header_nritems(leaf);
1573 for (i = 0; i < nritems; i++) {
1574 cond_resched();
1575 btrfs_item_key_to_cpu(leaf, &key, i);
1576 if (key.type != BTRFS_EXTENT_DATA_KEY)
1577 continue;
1578 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1579 if (btrfs_file_extent_type(leaf, fi) ==
1580 BTRFS_FILE_EXTENT_INLINE)
1581 continue;
1582 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1583 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1584 if (bytenr == 0)
1585 continue;
1586 if (!in_block_group(bytenr, rc->block_group))
1587 continue;
1588
1589 /*
1590 * if we are modifying block in fs tree, wait for readpage
1591 * to complete and drop the extent cache
1592 */
1593 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1594 if (first) {
1595 inode = find_next_inode(root, key.objectid);
1596 first = 0;
1597 } else if (inode && btrfs_ino(inode) < key.objectid) {
1598 btrfs_add_delayed_iput(inode);
1599 inode = find_next_inode(root, key.objectid);
1600 }
1601 if (inode && btrfs_ino(inode) == key.objectid) {
1602 end = key.offset +
1603 btrfs_file_extent_num_bytes(leaf, fi);
1604 WARN_ON(!IS_ALIGNED(key.offset,
1605 root->sectorsize));
1606 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1607 end--;
1608 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1609 key.offset, end);
1610 if (!ret)
1611 continue;
1612
1613 btrfs_drop_extent_cache(inode, key.offset, end,
1614 1);
1615 unlock_extent(&BTRFS_I(inode)->io_tree,
1616 key.offset, end);
1617 }
1618 }
1619
1620 ret = get_new_location(rc->data_inode, &new_bytenr,
1621 bytenr, num_bytes);
1622 if (ret > 0) {
1623 WARN_ON(1);
1624 continue;
1625 }
1626 BUG_ON(ret < 0);
1627
1628 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1629 dirty = 1;
1630
1631 key.offset -= btrfs_file_extent_offset(leaf, fi);
1632 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1633 num_bytes, parent,
1634 btrfs_header_owner(leaf),
1635 key.objectid, key.offset, 1);
1636 BUG_ON(ret);
1637
1638 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1639 parent, btrfs_header_owner(leaf),
1640 key.objectid, key.offset, 1);
1641 BUG_ON(ret);
1642 }
1643 if (dirty)
1644 btrfs_mark_buffer_dirty(leaf);
1645 if (inode)
1646 btrfs_add_delayed_iput(inode);
1647 return 0;
1648 }
1649
1650 static noinline_for_stack
1651 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1652 struct btrfs_path *path, int level)
1653 {
1654 struct btrfs_disk_key key1;
1655 struct btrfs_disk_key key2;
1656 btrfs_node_key(eb, &key1, slot);
1657 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1658 return memcmp(&key1, &key2, sizeof(key1));
1659 }
1660
1661 /*
1662 * try to replace tree blocks in fs tree with the new blocks
1663 * in reloc tree. tree blocks haven't been modified since the
1664 * reloc tree was create can be replaced.
1665 *
1666 * if a block was replaced, level of the block + 1 is returned.
1667 * if no block got replaced, 0 is returned. if there are other
1668 * errors, a negative error number is returned.
1669 */
1670 static noinline_for_stack
1671 int replace_path(struct btrfs_trans_handle *trans,
1672 struct btrfs_root *dest, struct btrfs_root *src,
1673 struct btrfs_path *path, struct btrfs_key *next_key,
1674 int lowest_level, int max_level)
1675 {
1676 struct extent_buffer *eb;
1677 struct extent_buffer *parent;
1678 struct btrfs_key key;
1679 u64 old_bytenr;
1680 u64 new_bytenr;
1681 u64 old_ptr_gen;
1682 u64 new_ptr_gen;
1683 u64 last_snapshot;
1684 u32 blocksize;
1685 int cow = 0;
1686 int level;
1687 int ret;
1688 int slot;
1689
1690 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1691 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1692
1693 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1694 again:
1695 slot = path->slots[lowest_level];
1696 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1697
1698 eb = btrfs_lock_root_node(dest);
1699 btrfs_set_lock_blocking(eb);
1700 level = btrfs_header_level(eb);
1701
1702 if (level < lowest_level) {
1703 btrfs_tree_unlock(eb);
1704 free_extent_buffer(eb);
1705 return 0;
1706 }
1707
1708 if (cow) {
1709 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1710 BUG_ON(ret);
1711 }
1712 btrfs_set_lock_blocking(eb);
1713
1714 if (next_key) {
1715 next_key->objectid = (u64)-1;
1716 next_key->type = (u8)-1;
1717 next_key->offset = (u64)-1;
1718 }
1719
1720 parent = eb;
1721 while (1) {
1722 level = btrfs_header_level(parent);
1723 BUG_ON(level < lowest_level);
1724
1725 ret = btrfs_bin_search(parent, &key, level, &slot);
1726 if (ret && slot > 0)
1727 slot--;
1728
1729 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1730 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1731
1732 old_bytenr = btrfs_node_blockptr(parent, slot);
1733 blocksize = btrfs_level_size(dest, level - 1);
1734 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1735
1736 if (level <= max_level) {
1737 eb = path->nodes[level];
1738 new_bytenr = btrfs_node_blockptr(eb,
1739 path->slots[level]);
1740 new_ptr_gen = btrfs_node_ptr_generation(eb,
1741 path->slots[level]);
1742 } else {
1743 new_bytenr = 0;
1744 new_ptr_gen = 0;
1745 }
1746
1747 if (new_bytenr > 0 && new_bytenr == old_bytenr) {
1748 WARN_ON(1);
1749 ret = level;
1750 break;
1751 }
1752
1753 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1754 memcmp_node_keys(parent, slot, path, level)) {
1755 if (level <= lowest_level) {
1756 ret = 0;
1757 break;
1758 }
1759
1760 eb = read_tree_block(dest, old_bytenr, blocksize,
1761 old_ptr_gen);
1762 BUG_ON(!eb);
1763 btrfs_tree_lock(eb);
1764 if (cow) {
1765 ret = btrfs_cow_block(trans, dest, eb, parent,
1766 slot, &eb);
1767 BUG_ON(ret);
1768 }
1769 btrfs_set_lock_blocking(eb);
1770
1771 btrfs_tree_unlock(parent);
1772 free_extent_buffer(parent);
1773
1774 parent = eb;
1775 continue;
1776 }
1777
1778 if (!cow) {
1779 btrfs_tree_unlock(parent);
1780 free_extent_buffer(parent);
1781 cow = 1;
1782 goto again;
1783 }
1784
1785 btrfs_node_key_to_cpu(path->nodes[level], &key,
1786 path->slots[level]);
1787 btrfs_release_path(path);
1788
1789 path->lowest_level = level;
1790 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1791 path->lowest_level = 0;
1792 BUG_ON(ret);
1793
1794 /*
1795 * swap blocks in fs tree and reloc tree.
1796 */
1797 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1798 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1799 btrfs_mark_buffer_dirty(parent);
1800
1801 btrfs_set_node_blockptr(path->nodes[level],
1802 path->slots[level], old_bytenr);
1803 btrfs_set_node_ptr_generation(path->nodes[level],
1804 path->slots[level], old_ptr_gen);
1805 btrfs_mark_buffer_dirty(path->nodes[level]);
1806
1807 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1808 path->nodes[level]->start,
1809 src->root_key.objectid, level - 1, 0,
1810 1);
1811 BUG_ON(ret);
1812 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1813 0, dest->root_key.objectid, level - 1,
1814 0, 1);
1815 BUG_ON(ret);
1816
1817 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1818 path->nodes[level]->start,
1819 src->root_key.objectid, level - 1, 0,
1820 1);
1821 BUG_ON(ret);
1822
1823 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1824 0, dest->root_key.objectid, level - 1,
1825 0, 1);
1826 BUG_ON(ret);
1827
1828 btrfs_unlock_up_safe(path, 0);
1829
1830 ret = level;
1831 break;
1832 }
1833 btrfs_tree_unlock(parent);
1834 free_extent_buffer(parent);
1835 return ret;
1836 }
1837
1838 /*
1839 * helper to find next relocated block in reloc tree
1840 */
1841 static noinline_for_stack
1842 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1843 int *level)
1844 {
1845 struct extent_buffer *eb;
1846 int i;
1847 u64 last_snapshot;
1848 u32 nritems;
1849
1850 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1851
1852 for (i = 0; i < *level; i++) {
1853 free_extent_buffer(path->nodes[i]);
1854 path->nodes[i] = NULL;
1855 }
1856
1857 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1858 eb = path->nodes[i];
1859 nritems = btrfs_header_nritems(eb);
1860 while (path->slots[i] + 1 < nritems) {
1861 path->slots[i]++;
1862 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1863 last_snapshot)
1864 continue;
1865
1866 *level = i;
1867 return 0;
1868 }
1869 free_extent_buffer(path->nodes[i]);
1870 path->nodes[i] = NULL;
1871 }
1872 return 1;
1873 }
1874
1875 /*
1876 * walk down reloc tree to find relocated block of lowest level
1877 */
1878 static noinline_for_stack
1879 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1880 int *level)
1881 {
1882 struct extent_buffer *eb = NULL;
1883 int i;
1884 u64 bytenr;
1885 u64 ptr_gen = 0;
1886 u64 last_snapshot;
1887 u32 blocksize;
1888 u32 nritems;
1889
1890 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1891
1892 for (i = *level; i > 0; i--) {
1893 eb = path->nodes[i];
1894 nritems = btrfs_header_nritems(eb);
1895 while (path->slots[i] < nritems) {
1896 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1897 if (ptr_gen > last_snapshot)
1898 break;
1899 path->slots[i]++;
1900 }
1901 if (path->slots[i] >= nritems) {
1902 if (i == *level)
1903 break;
1904 *level = i + 1;
1905 return 0;
1906 }
1907 if (i == 1) {
1908 *level = i;
1909 return 0;
1910 }
1911
1912 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1913 blocksize = btrfs_level_size(root, i - 1);
1914 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1915 BUG_ON(btrfs_header_level(eb) != i - 1);
1916 path->nodes[i - 1] = eb;
1917 path->slots[i - 1] = 0;
1918 }
1919 return 1;
1920 }
1921
1922 /*
1923 * invalidate extent cache for file extents whose key in range of
1924 * [min_key, max_key)
1925 */
1926 static int invalidate_extent_cache(struct btrfs_root *root,
1927 struct btrfs_key *min_key,
1928 struct btrfs_key *max_key)
1929 {
1930 struct inode *inode = NULL;
1931 u64 objectid;
1932 u64 start, end;
1933 u64 ino;
1934
1935 objectid = min_key->objectid;
1936 while (1) {
1937 cond_resched();
1938 iput(inode);
1939
1940 if (objectid > max_key->objectid)
1941 break;
1942
1943 inode = find_next_inode(root, objectid);
1944 if (!inode)
1945 break;
1946 ino = btrfs_ino(inode);
1947
1948 if (ino > max_key->objectid) {
1949 iput(inode);
1950 break;
1951 }
1952
1953 objectid = ino + 1;
1954 if (!S_ISREG(inode->i_mode))
1955 continue;
1956
1957 if (unlikely(min_key->objectid == ino)) {
1958 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1959 continue;
1960 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1961 start = 0;
1962 else {
1963 start = min_key->offset;
1964 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
1965 }
1966 } else {
1967 start = 0;
1968 }
1969
1970 if (unlikely(max_key->objectid == ino)) {
1971 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1972 continue;
1973 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1974 end = (u64)-1;
1975 } else {
1976 if (max_key->offset == 0)
1977 continue;
1978 end = max_key->offset;
1979 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1980 end--;
1981 }
1982 } else {
1983 end = (u64)-1;
1984 }
1985
1986 /* the lock_extent waits for readpage to complete */
1987 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
1988 btrfs_drop_extent_cache(inode, start, end, 1);
1989 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
1990 }
1991 return 0;
1992 }
1993
1994 static int find_next_key(struct btrfs_path *path, int level,
1995 struct btrfs_key *key)
1996
1997 {
1998 while (level < BTRFS_MAX_LEVEL) {
1999 if (!path->nodes[level])
2000 break;
2001 if (path->slots[level] + 1 <
2002 btrfs_header_nritems(path->nodes[level])) {
2003 btrfs_node_key_to_cpu(path->nodes[level], key,
2004 path->slots[level] + 1);
2005 return 0;
2006 }
2007 level++;
2008 }
2009 return 1;
2010 }
2011
2012 /*
2013 * merge the relocated tree blocks in reloc tree with corresponding
2014 * fs tree.
2015 */
2016 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2017 struct btrfs_root *root)
2018 {
2019 LIST_HEAD(inode_list);
2020 struct btrfs_key key;
2021 struct btrfs_key next_key;
2022 struct btrfs_trans_handle *trans;
2023 struct btrfs_root *reloc_root;
2024 struct btrfs_root_item *root_item;
2025 struct btrfs_path *path;
2026 struct extent_buffer *leaf;
2027 unsigned long nr;
2028 int level;
2029 int max_level;
2030 int replaced = 0;
2031 int ret;
2032 int err = 0;
2033 u32 min_reserved;
2034
2035 path = btrfs_alloc_path();
2036 if (!path)
2037 return -ENOMEM;
2038 path->reada = 1;
2039
2040 reloc_root = root->reloc_root;
2041 root_item = &reloc_root->root_item;
2042
2043 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2044 level = btrfs_root_level(root_item);
2045 extent_buffer_get(reloc_root->node);
2046 path->nodes[level] = reloc_root->node;
2047 path->slots[level] = 0;
2048 } else {
2049 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2050
2051 level = root_item->drop_level;
2052 BUG_ON(level == 0);
2053 path->lowest_level = level;
2054 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2055 path->lowest_level = 0;
2056 if (ret < 0) {
2057 btrfs_free_path(path);
2058 return ret;
2059 }
2060
2061 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2062 path->slots[level]);
2063 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2064
2065 btrfs_unlock_up_safe(path, 0);
2066 }
2067
2068 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2069 memset(&next_key, 0, sizeof(next_key));
2070
2071 while (1) {
2072 trans = btrfs_start_transaction(root, 0);
2073 BUG_ON(IS_ERR(trans));
2074 trans->block_rsv = rc->block_rsv;
2075
2076 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved);
2077 if (ret) {
2078 BUG_ON(ret != -EAGAIN);
2079 ret = btrfs_commit_transaction(trans, root);
2080 BUG_ON(ret);
2081 continue;
2082 }
2083
2084 replaced = 0;
2085 max_level = level;
2086
2087 ret = walk_down_reloc_tree(reloc_root, path, &level);
2088 if (ret < 0) {
2089 err = ret;
2090 goto out;
2091 }
2092 if (ret > 0)
2093 break;
2094
2095 if (!find_next_key(path, level, &key) &&
2096 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2097 ret = 0;
2098 } else {
2099 ret = replace_path(trans, root, reloc_root, path,
2100 &next_key, level, max_level);
2101 }
2102 if (ret < 0) {
2103 err = ret;
2104 goto out;
2105 }
2106
2107 if (ret > 0) {
2108 level = ret;
2109 btrfs_node_key_to_cpu(path->nodes[level], &key,
2110 path->slots[level]);
2111 replaced = 1;
2112 }
2113
2114 ret = walk_up_reloc_tree(reloc_root, path, &level);
2115 if (ret > 0)
2116 break;
2117
2118 BUG_ON(level == 0);
2119 /*
2120 * save the merging progress in the drop_progress.
2121 * this is OK since root refs == 1 in this case.
2122 */
2123 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2124 path->slots[level]);
2125 root_item->drop_level = level;
2126
2127 nr = trans->blocks_used;
2128 btrfs_end_transaction_throttle(trans, root);
2129
2130 btrfs_btree_balance_dirty(root, nr);
2131
2132 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2133 invalidate_extent_cache(root, &key, &next_key);
2134 }
2135
2136 /*
2137 * handle the case only one block in the fs tree need to be
2138 * relocated and the block is tree root.
2139 */
2140 leaf = btrfs_lock_root_node(root);
2141 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2142 btrfs_tree_unlock(leaf);
2143 free_extent_buffer(leaf);
2144 if (ret < 0)
2145 err = ret;
2146 out:
2147 btrfs_free_path(path);
2148
2149 if (err == 0) {
2150 memset(&root_item->drop_progress, 0,
2151 sizeof(root_item->drop_progress));
2152 root_item->drop_level = 0;
2153 btrfs_set_root_refs(root_item, 0);
2154 btrfs_update_reloc_root(trans, root);
2155 }
2156
2157 nr = trans->blocks_used;
2158 btrfs_end_transaction_throttle(trans, root);
2159
2160 btrfs_btree_balance_dirty(root, nr);
2161
2162 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2163 invalidate_extent_cache(root, &key, &next_key);
2164
2165 return err;
2166 }
2167
2168 static noinline_for_stack
2169 int prepare_to_merge(struct reloc_control *rc, int err)
2170 {
2171 struct btrfs_root *root = rc->extent_root;
2172 struct btrfs_root *reloc_root;
2173 struct btrfs_trans_handle *trans;
2174 LIST_HEAD(reloc_roots);
2175 u64 num_bytes = 0;
2176 int ret;
2177
2178 mutex_lock(&root->fs_info->reloc_mutex);
2179 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2180 rc->merging_rsv_size += rc->nodes_relocated * 2;
2181 mutex_unlock(&root->fs_info->reloc_mutex);
2182
2183 again:
2184 if (!err) {
2185 num_bytes = rc->merging_rsv_size;
2186 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2187 if (ret)
2188 err = ret;
2189 }
2190
2191 trans = btrfs_join_transaction(rc->extent_root);
2192 if (IS_ERR(trans)) {
2193 if (!err)
2194 btrfs_block_rsv_release(rc->extent_root,
2195 rc->block_rsv, num_bytes);
2196 return PTR_ERR(trans);
2197 }
2198
2199 if (!err) {
2200 if (num_bytes != rc->merging_rsv_size) {
2201 btrfs_end_transaction(trans, rc->extent_root);
2202 btrfs_block_rsv_release(rc->extent_root,
2203 rc->block_rsv, num_bytes);
2204 goto again;
2205 }
2206 }
2207
2208 rc->merge_reloc_tree = 1;
2209
2210 while (!list_empty(&rc->reloc_roots)) {
2211 reloc_root = list_entry(rc->reloc_roots.next,
2212 struct btrfs_root, root_list);
2213 list_del_init(&reloc_root->root_list);
2214
2215 root = read_fs_root(reloc_root->fs_info,
2216 reloc_root->root_key.offset);
2217 BUG_ON(IS_ERR(root));
2218 BUG_ON(root->reloc_root != reloc_root);
2219
2220 /*
2221 * set reference count to 1, so btrfs_recover_relocation
2222 * knows it should resumes merging
2223 */
2224 if (!err)
2225 btrfs_set_root_refs(&reloc_root->root_item, 1);
2226 btrfs_update_reloc_root(trans, root);
2227
2228 list_add(&reloc_root->root_list, &reloc_roots);
2229 }
2230
2231 list_splice(&reloc_roots, &rc->reloc_roots);
2232
2233 if (!err)
2234 btrfs_commit_transaction(trans, rc->extent_root);
2235 else
2236 btrfs_end_transaction(trans, rc->extent_root);
2237 return err;
2238 }
2239
2240 static noinline_for_stack
2241 int merge_reloc_roots(struct reloc_control *rc)
2242 {
2243 struct btrfs_root *root;
2244 struct btrfs_root *reloc_root;
2245 LIST_HEAD(reloc_roots);
2246 int found = 0;
2247 int ret;
2248 again:
2249 root = rc->extent_root;
2250
2251 /*
2252 * this serializes us with btrfs_record_root_in_transaction,
2253 * we have to make sure nobody is in the middle of
2254 * adding their roots to the list while we are
2255 * doing this splice
2256 */
2257 mutex_lock(&root->fs_info->reloc_mutex);
2258 list_splice_init(&rc->reloc_roots, &reloc_roots);
2259 mutex_unlock(&root->fs_info->reloc_mutex);
2260
2261 while (!list_empty(&reloc_roots)) {
2262 found = 1;
2263 reloc_root = list_entry(reloc_roots.next,
2264 struct btrfs_root, root_list);
2265
2266 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2267 root = read_fs_root(reloc_root->fs_info,
2268 reloc_root->root_key.offset);
2269 BUG_ON(IS_ERR(root));
2270 BUG_ON(root->reloc_root != reloc_root);
2271
2272 ret = merge_reloc_root(rc, root);
2273 BUG_ON(ret);
2274 } else {
2275 list_del_init(&reloc_root->root_list);
2276 }
2277 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2278 BUG_ON(ret < 0);
2279 }
2280
2281 if (found) {
2282 found = 0;
2283 goto again;
2284 }
2285 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2286 return 0;
2287 }
2288
2289 static void free_block_list(struct rb_root *blocks)
2290 {
2291 struct tree_block *block;
2292 struct rb_node *rb_node;
2293 while ((rb_node = rb_first(blocks))) {
2294 block = rb_entry(rb_node, struct tree_block, rb_node);
2295 rb_erase(rb_node, blocks);
2296 kfree(block);
2297 }
2298 }
2299
2300 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2301 struct btrfs_root *reloc_root)
2302 {
2303 struct btrfs_root *root;
2304
2305 if (reloc_root->last_trans == trans->transid)
2306 return 0;
2307
2308 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2309 BUG_ON(IS_ERR(root));
2310 BUG_ON(root->reloc_root != reloc_root);
2311
2312 return btrfs_record_root_in_trans(trans, root);
2313 }
2314
2315 static noinline_for_stack
2316 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2317 struct reloc_control *rc,
2318 struct backref_node *node,
2319 struct backref_edge *edges[], int *nr)
2320 {
2321 struct backref_node *next;
2322 struct btrfs_root *root;
2323 int index = 0;
2324
2325 next = node;
2326 while (1) {
2327 cond_resched();
2328 next = walk_up_backref(next, edges, &index);
2329 root = next->root;
2330 BUG_ON(!root);
2331 BUG_ON(!root->ref_cows);
2332
2333 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2334 record_reloc_root_in_trans(trans, root);
2335 break;
2336 }
2337
2338 btrfs_record_root_in_trans(trans, root);
2339 root = root->reloc_root;
2340
2341 if (next->new_bytenr != root->node->start) {
2342 BUG_ON(next->new_bytenr);
2343 BUG_ON(!list_empty(&next->list));
2344 next->new_bytenr = root->node->start;
2345 next->root = root;
2346 list_add_tail(&next->list,
2347 &rc->backref_cache.changed);
2348 __mark_block_processed(rc, next);
2349 break;
2350 }
2351
2352 WARN_ON(1);
2353 root = NULL;
2354 next = walk_down_backref(edges, &index);
2355 if (!next || next->level <= node->level)
2356 break;
2357 }
2358 if (!root)
2359 return NULL;
2360
2361 *nr = index;
2362 next = node;
2363 /* setup backref node path for btrfs_reloc_cow_block */
2364 while (1) {
2365 rc->backref_cache.path[next->level] = next;
2366 if (--index < 0)
2367 break;
2368 next = edges[index]->node[UPPER];
2369 }
2370 return root;
2371 }
2372
2373 /*
2374 * select a tree root for relocation. return NULL if the block
2375 * is reference counted. we should use do_relocation() in this
2376 * case. return a tree root pointer if the block isn't reference
2377 * counted. return -ENOENT if the block is root of reloc tree.
2378 */
2379 static noinline_for_stack
2380 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2381 struct backref_node *node)
2382 {
2383 struct backref_node *next;
2384 struct btrfs_root *root;
2385 struct btrfs_root *fs_root = NULL;
2386 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2387 int index = 0;
2388
2389 next = node;
2390 while (1) {
2391 cond_resched();
2392 next = walk_up_backref(next, edges, &index);
2393 root = next->root;
2394 BUG_ON(!root);
2395
2396 /* no other choice for non-references counted tree */
2397 if (!root->ref_cows)
2398 return root;
2399
2400 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2401 fs_root = root;
2402
2403 if (next != node)
2404 return NULL;
2405
2406 next = walk_down_backref(edges, &index);
2407 if (!next || next->level <= node->level)
2408 break;
2409 }
2410
2411 if (!fs_root)
2412 return ERR_PTR(-ENOENT);
2413 return fs_root;
2414 }
2415
2416 static noinline_for_stack
2417 u64 calcu_metadata_size(struct reloc_control *rc,
2418 struct backref_node *node, int reserve)
2419 {
2420 struct backref_node *next = node;
2421 struct backref_edge *edge;
2422 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2423 u64 num_bytes = 0;
2424 int index = 0;
2425
2426 BUG_ON(reserve && node->processed);
2427
2428 while (next) {
2429 cond_resched();
2430 while (1) {
2431 if (next->processed && (reserve || next != node))
2432 break;
2433
2434 num_bytes += btrfs_level_size(rc->extent_root,
2435 next->level);
2436
2437 if (list_empty(&next->upper))
2438 break;
2439
2440 edge = list_entry(next->upper.next,
2441 struct backref_edge, list[LOWER]);
2442 edges[index++] = edge;
2443 next = edge->node[UPPER];
2444 }
2445 next = walk_down_backref(edges, &index);
2446 }
2447 return num_bytes;
2448 }
2449
2450 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2451 struct reloc_control *rc,
2452 struct backref_node *node)
2453 {
2454 struct btrfs_root *root = rc->extent_root;
2455 u64 num_bytes;
2456 int ret;
2457
2458 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2459
2460 trans->block_rsv = rc->block_rsv;
2461 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes);
2462 if (ret) {
2463 if (ret == -EAGAIN)
2464 rc->commit_transaction = 1;
2465 return ret;
2466 }
2467
2468 return 0;
2469 }
2470
2471 static void release_metadata_space(struct reloc_control *rc,
2472 struct backref_node *node)
2473 {
2474 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2475 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2476 }
2477
2478 /*
2479 * relocate a block tree, and then update pointers in upper level
2480 * blocks that reference the block to point to the new location.
2481 *
2482 * if called by link_to_upper, the block has already been relocated.
2483 * in that case this function just updates pointers.
2484 */
2485 static int do_relocation(struct btrfs_trans_handle *trans,
2486 struct reloc_control *rc,
2487 struct backref_node *node,
2488 struct btrfs_key *key,
2489 struct btrfs_path *path, int lowest)
2490 {
2491 struct backref_node *upper;
2492 struct backref_edge *edge;
2493 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2494 struct btrfs_root *root;
2495 struct extent_buffer *eb;
2496 u32 blocksize;
2497 u64 bytenr;
2498 u64 generation;
2499 int nr;
2500 int slot;
2501 int ret;
2502 int err = 0;
2503
2504 BUG_ON(lowest && node->eb);
2505
2506 path->lowest_level = node->level + 1;
2507 rc->backref_cache.path[node->level] = node;
2508 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2509 cond_resched();
2510
2511 upper = edge->node[UPPER];
2512 root = select_reloc_root(trans, rc, upper, edges, &nr);
2513 BUG_ON(!root);
2514
2515 if (upper->eb && !upper->locked) {
2516 if (!lowest) {
2517 ret = btrfs_bin_search(upper->eb, key,
2518 upper->level, &slot);
2519 BUG_ON(ret);
2520 bytenr = btrfs_node_blockptr(upper->eb, slot);
2521 if (node->eb->start == bytenr)
2522 goto next;
2523 }
2524 drop_node_buffer(upper);
2525 }
2526
2527 if (!upper->eb) {
2528 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2529 if (ret < 0) {
2530 err = ret;
2531 break;
2532 }
2533 BUG_ON(ret > 0);
2534
2535 if (!upper->eb) {
2536 upper->eb = path->nodes[upper->level];
2537 path->nodes[upper->level] = NULL;
2538 } else {
2539 BUG_ON(upper->eb != path->nodes[upper->level]);
2540 }
2541
2542 upper->locked = 1;
2543 path->locks[upper->level] = 0;
2544
2545 slot = path->slots[upper->level];
2546 btrfs_release_path(path);
2547 } else {
2548 ret = btrfs_bin_search(upper->eb, key, upper->level,
2549 &slot);
2550 BUG_ON(ret);
2551 }
2552
2553 bytenr = btrfs_node_blockptr(upper->eb, slot);
2554 if (lowest) {
2555 BUG_ON(bytenr != node->bytenr);
2556 } else {
2557 if (node->eb->start == bytenr)
2558 goto next;
2559 }
2560
2561 blocksize = btrfs_level_size(root, node->level);
2562 generation = btrfs_node_ptr_generation(upper->eb, slot);
2563 eb = read_tree_block(root, bytenr, blocksize, generation);
2564 if (!eb) {
2565 err = -EIO;
2566 goto next;
2567 }
2568 btrfs_tree_lock(eb);
2569 btrfs_set_lock_blocking(eb);
2570
2571 if (!node->eb) {
2572 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2573 slot, &eb);
2574 btrfs_tree_unlock(eb);
2575 free_extent_buffer(eb);
2576 if (ret < 0) {
2577 err = ret;
2578 goto next;
2579 }
2580 BUG_ON(node->eb != eb);
2581 } else {
2582 btrfs_set_node_blockptr(upper->eb, slot,
2583 node->eb->start);
2584 btrfs_set_node_ptr_generation(upper->eb, slot,
2585 trans->transid);
2586 btrfs_mark_buffer_dirty(upper->eb);
2587
2588 ret = btrfs_inc_extent_ref(trans, root,
2589 node->eb->start, blocksize,
2590 upper->eb->start,
2591 btrfs_header_owner(upper->eb),
2592 node->level, 0, 1);
2593 BUG_ON(ret);
2594
2595 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2596 BUG_ON(ret);
2597 }
2598 next:
2599 if (!upper->pending)
2600 drop_node_buffer(upper);
2601 else
2602 unlock_node_buffer(upper);
2603 if (err)
2604 break;
2605 }
2606
2607 if (!err && node->pending) {
2608 drop_node_buffer(node);
2609 list_move_tail(&node->list, &rc->backref_cache.changed);
2610 node->pending = 0;
2611 }
2612
2613 path->lowest_level = 0;
2614 BUG_ON(err == -ENOSPC);
2615 return err;
2616 }
2617
2618 static int link_to_upper(struct btrfs_trans_handle *trans,
2619 struct reloc_control *rc,
2620 struct backref_node *node,
2621 struct btrfs_path *path)
2622 {
2623 struct btrfs_key key;
2624
2625 btrfs_node_key_to_cpu(node->eb, &key, 0);
2626 return do_relocation(trans, rc, node, &key, path, 0);
2627 }
2628
2629 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2630 struct reloc_control *rc,
2631 struct btrfs_path *path, int err)
2632 {
2633 LIST_HEAD(list);
2634 struct backref_cache *cache = &rc->backref_cache;
2635 struct backref_node *node;
2636 int level;
2637 int ret;
2638
2639 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2640 while (!list_empty(&cache->pending[level])) {
2641 node = list_entry(cache->pending[level].next,
2642 struct backref_node, list);
2643 list_move_tail(&node->list, &list);
2644 BUG_ON(!node->pending);
2645
2646 if (!err) {
2647 ret = link_to_upper(trans, rc, node, path);
2648 if (ret < 0)
2649 err = ret;
2650 }
2651 }
2652 list_splice_init(&list, &cache->pending[level]);
2653 }
2654 return err;
2655 }
2656
2657 static void mark_block_processed(struct reloc_control *rc,
2658 u64 bytenr, u32 blocksize)
2659 {
2660 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2661 EXTENT_DIRTY, GFP_NOFS);
2662 }
2663
2664 static void __mark_block_processed(struct reloc_control *rc,
2665 struct backref_node *node)
2666 {
2667 u32 blocksize;
2668 if (node->level == 0 ||
2669 in_block_group(node->bytenr, rc->block_group)) {
2670 blocksize = btrfs_level_size(rc->extent_root, node->level);
2671 mark_block_processed(rc, node->bytenr, blocksize);
2672 }
2673 node->processed = 1;
2674 }
2675
2676 /*
2677 * mark a block and all blocks directly/indirectly reference the block
2678 * as processed.
2679 */
2680 static void update_processed_blocks(struct reloc_control *rc,
2681 struct backref_node *node)
2682 {
2683 struct backref_node *next = node;
2684 struct backref_edge *edge;
2685 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2686 int index = 0;
2687
2688 while (next) {
2689 cond_resched();
2690 while (1) {
2691 if (next->processed)
2692 break;
2693
2694 __mark_block_processed(rc, next);
2695
2696 if (list_empty(&next->upper))
2697 break;
2698
2699 edge = list_entry(next->upper.next,
2700 struct backref_edge, list[LOWER]);
2701 edges[index++] = edge;
2702 next = edge->node[UPPER];
2703 }
2704 next = walk_down_backref(edges, &index);
2705 }
2706 }
2707
2708 static int tree_block_processed(u64 bytenr, u32 blocksize,
2709 struct reloc_control *rc)
2710 {
2711 if (test_range_bit(&rc->processed_blocks, bytenr,
2712 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2713 return 1;
2714 return 0;
2715 }
2716
2717 static int get_tree_block_key(struct reloc_control *rc,
2718 struct tree_block *block)
2719 {
2720 struct extent_buffer *eb;
2721
2722 BUG_ON(block->key_ready);
2723 eb = read_tree_block(rc->extent_root, block->bytenr,
2724 block->key.objectid, block->key.offset);
2725 BUG_ON(!eb);
2726 WARN_ON(btrfs_header_level(eb) != block->level);
2727 if (block->level == 0)
2728 btrfs_item_key_to_cpu(eb, &block->key, 0);
2729 else
2730 btrfs_node_key_to_cpu(eb, &block->key, 0);
2731 free_extent_buffer(eb);
2732 block->key_ready = 1;
2733 return 0;
2734 }
2735
2736 static int reada_tree_block(struct reloc_control *rc,
2737 struct tree_block *block)
2738 {
2739 BUG_ON(block->key_ready);
2740 readahead_tree_block(rc->extent_root, block->bytenr,
2741 block->key.objectid, block->key.offset);
2742 return 0;
2743 }
2744
2745 /*
2746 * helper function to relocate a tree block
2747 */
2748 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2749 struct reloc_control *rc,
2750 struct backref_node *node,
2751 struct btrfs_key *key,
2752 struct btrfs_path *path)
2753 {
2754 struct btrfs_root *root;
2755 int release = 0;
2756 int ret = 0;
2757
2758 if (!node)
2759 return 0;
2760
2761 BUG_ON(node->processed);
2762 root = select_one_root(trans, node);
2763 if (root == ERR_PTR(-ENOENT)) {
2764 update_processed_blocks(rc, node);
2765 goto out;
2766 }
2767
2768 if (!root || root->ref_cows) {
2769 ret = reserve_metadata_space(trans, rc, node);
2770 if (ret)
2771 goto out;
2772 release = 1;
2773 }
2774
2775 if (root) {
2776 if (root->ref_cows) {
2777 BUG_ON(node->new_bytenr);
2778 BUG_ON(!list_empty(&node->list));
2779 btrfs_record_root_in_trans(trans, root);
2780 root = root->reloc_root;
2781 node->new_bytenr = root->node->start;
2782 node->root = root;
2783 list_add_tail(&node->list, &rc->backref_cache.changed);
2784 } else {
2785 path->lowest_level = node->level;
2786 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2787 btrfs_release_path(path);
2788 if (ret > 0)
2789 ret = 0;
2790 }
2791 if (!ret)
2792 update_processed_blocks(rc, node);
2793 } else {
2794 ret = do_relocation(trans, rc, node, key, path, 1);
2795 }
2796 out:
2797 if (ret || node->level == 0 || node->cowonly) {
2798 if (release)
2799 release_metadata_space(rc, node);
2800 remove_backref_node(&rc->backref_cache, node);
2801 }
2802 return ret;
2803 }
2804
2805 /*
2806 * relocate a list of blocks
2807 */
2808 static noinline_for_stack
2809 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2810 struct reloc_control *rc, struct rb_root *blocks)
2811 {
2812 struct backref_node *node;
2813 struct btrfs_path *path;
2814 struct tree_block *block;
2815 struct rb_node *rb_node;
2816 int ret;
2817 int err = 0;
2818
2819 path = btrfs_alloc_path();
2820 if (!path)
2821 return -ENOMEM;
2822
2823 rb_node = rb_first(blocks);
2824 while (rb_node) {
2825 block = rb_entry(rb_node, struct tree_block, rb_node);
2826 if (!block->key_ready)
2827 reada_tree_block(rc, block);
2828 rb_node = rb_next(rb_node);
2829 }
2830
2831 rb_node = rb_first(blocks);
2832 while (rb_node) {
2833 block = rb_entry(rb_node, struct tree_block, rb_node);
2834 if (!block->key_ready)
2835 get_tree_block_key(rc, block);
2836 rb_node = rb_next(rb_node);
2837 }
2838
2839 rb_node = rb_first(blocks);
2840 while (rb_node) {
2841 block = rb_entry(rb_node, struct tree_block, rb_node);
2842
2843 node = build_backref_tree(rc, &block->key,
2844 block->level, block->bytenr);
2845 if (IS_ERR(node)) {
2846 err = PTR_ERR(node);
2847 goto out;
2848 }
2849
2850 ret = relocate_tree_block(trans, rc, node, &block->key,
2851 path);
2852 if (ret < 0) {
2853 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2854 err = ret;
2855 goto out;
2856 }
2857 rb_node = rb_next(rb_node);
2858 }
2859 out:
2860 free_block_list(blocks);
2861 err = finish_pending_nodes(trans, rc, path, err);
2862
2863 btrfs_free_path(path);
2864 return err;
2865 }
2866
2867 static noinline_for_stack
2868 int prealloc_file_extent_cluster(struct inode *inode,
2869 struct file_extent_cluster *cluster)
2870 {
2871 u64 alloc_hint = 0;
2872 u64 start;
2873 u64 end;
2874 u64 offset = BTRFS_I(inode)->index_cnt;
2875 u64 num_bytes;
2876 int nr = 0;
2877 int ret = 0;
2878
2879 BUG_ON(cluster->start != cluster->boundary[0]);
2880 mutex_lock(&inode->i_mutex);
2881
2882 ret = btrfs_check_data_free_space(inode, cluster->end +
2883 1 - cluster->start);
2884 if (ret)
2885 goto out;
2886
2887 while (nr < cluster->nr) {
2888 start = cluster->boundary[nr] - offset;
2889 if (nr + 1 < cluster->nr)
2890 end = cluster->boundary[nr + 1] - 1 - offset;
2891 else
2892 end = cluster->end - offset;
2893
2894 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2895 num_bytes = end + 1 - start;
2896 ret = btrfs_prealloc_file_range(inode, 0, start,
2897 num_bytes, num_bytes,
2898 end + 1, &alloc_hint);
2899 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2900 if (ret)
2901 break;
2902 nr++;
2903 }
2904 btrfs_free_reserved_data_space(inode, cluster->end +
2905 1 - cluster->start);
2906 out:
2907 mutex_unlock(&inode->i_mutex);
2908 return ret;
2909 }
2910
2911 static noinline_for_stack
2912 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
2913 u64 block_start)
2914 {
2915 struct btrfs_root *root = BTRFS_I(inode)->root;
2916 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
2917 struct extent_map *em;
2918 int ret = 0;
2919
2920 em = alloc_extent_map();
2921 if (!em)
2922 return -ENOMEM;
2923
2924 em->start = start;
2925 em->len = end + 1 - start;
2926 em->block_len = em->len;
2927 em->block_start = block_start;
2928 em->bdev = root->fs_info->fs_devices->latest_bdev;
2929 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2930
2931 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2932 while (1) {
2933 write_lock(&em_tree->lock);
2934 ret = add_extent_mapping(em_tree, em);
2935 write_unlock(&em_tree->lock);
2936 if (ret != -EEXIST) {
2937 free_extent_map(em);
2938 break;
2939 }
2940 btrfs_drop_extent_cache(inode, start, end, 0);
2941 }
2942 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2943 return ret;
2944 }
2945
2946 static int relocate_file_extent_cluster(struct inode *inode,
2947 struct file_extent_cluster *cluster)
2948 {
2949 u64 page_start;
2950 u64 page_end;
2951 u64 offset = BTRFS_I(inode)->index_cnt;
2952 unsigned long index;
2953 unsigned long last_index;
2954 struct page *page;
2955 struct file_ra_state *ra;
2956 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2957 int nr = 0;
2958 int ret = 0;
2959
2960 if (!cluster->nr)
2961 return 0;
2962
2963 ra = kzalloc(sizeof(*ra), GFP_NOFS);
2964 if (!ra)
2965 return -ENOMEM;
2966
2967 ret = prealloc_file_extent_cluster(inode, cluster);
2968 if (ret)
2969 goto out;
2970
2971 file_ra_state_init(ra, inode->i_mapping);
2972
2973 ret = setup_extent_mapping(inode, cluster->start - offset,
2974 cluster->end - offset, cluster->start);
2975 if (ret)
2976 goto out;
2977
2978 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
2979 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
2980 while (index <= last_index) {
2981 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
2982 if (ret)
2983 goto out;
2984
2985 page = find_lock_page(inode->i_mapping, index);
2986 if (!page) {
2987 page_cache_sync_readahead(inode->i_mapping,
2988 ra, NULL, index,
2989 last_index + 1 - index);
2990 page = find_or_create_page(inode->i_mapping, index,
2991 mask);
2992 if (!page) {
2993 btrfs_delalloc_release_metadata(inode,
2994 PAGE_CACHE_SIZE);
2995 ret = -ENOMEM;
2996 goto out;
2997 }
2998 }
2999
3000 if (PageReadahead(page)) {
3001 page_cache_async_readahead(inode->i_mapping,
3002 ra, NULL, page, index,
3003 last_index + 1 - index);
3004 }
3005
3006 if (!PageUptodate(page)) {
3007 btrfs_readpage(NULL, page);
3008 lock_page(page);
3009 if (!PageUptodate(page)) {
3010 unlock_page(page);
3011 page_cache_release(page);
3012 btrfs_delalloc_release_metadata(inode,
3013 PAGE_CACHE_SIZE);
3014 ret = -EIO;
3015 goto out;
3016 }
3017 }
3018
3019 page_start = (u64)page->index << PAGE_CACHE_SHIFT;
3020 page_end = page_start + PAGE_CACHE_SIZE - 1;
3021
3022 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3023
3024 set_page_extent_mapped(page);
3025
3026 if (nr < cluster->nr &&
3027 page_start + offset == cluster->boundary[nr]) {
3028 set_extent_bits(&BTRFS_I(inode)->io_tree,
3029 page_start, page_end,
3030 EXTENT_BOUNDARY, GFP_NOFS);
3031 nr++;
3032 }
3033
3034 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3035 set_page_dirty(page);
3036
3037 unlock_extent(&BTRFS_I(inode)->io_tree,
3038 page_start, page_end);
3039 unlock_page(page);
3040 page_cache_release(page);
3041
3042 index++;
3043 balance_dirty_pages_ratelimited(inode->i_mapping);
3044 btrfs_throttle(BTRFS_I(inode)->root);
3045 }
3046 WARN_ON(nr != cluster->nr);
3047 out:
3048 kfree(ra);
3049 return ret;
3050 }
3051
3052 static noinline_for_stack
3053 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3054 struct file_extent_cluster *cluster)
3055 {
3056 int ret;
3057
3058 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3059 ret = relocate_file_extent_cluster(inode, cluster);
3060 if (ret)
3061 return ret;
3062 cluster->nr = 0;
3063 }
3064
3065 if (!cluster->nr)
3066 cluster->start = extent_key->objectid;
3067 else
3068 BUG_ON(cluster->nr >= MAX_EXTENTS);
3069 cluster->end = extent_key->objectid + extent_key->offset - 1;
3070 cluster->boundary[cluster->nr] = extent_key->objectid;
3071 cluster->nr++;
3072
3073 if (cluster->nr >= MAX_EXTENTS) {
3074 ret = relocate_file_extent_cluster(inode, cluster);
3075 if (ret)
3076 return ret;
3077 cluster->nr = 0;
3078 }
3079 return 0;
3080 }
3081
3082 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3083 static int get_ref_objectid_v0(struct reloc_control *rc,
3084 struct btrfs_path *path,
3085 struct btrfs_key *extent_key,
3086 u64 *ref_objectid, int *path_change)
3087 {
3088 struct btrfs_key key;
3089 struct extent_buffer *leaf;
3090 struct btrfs_extent_ref_v0 *ref0;
3091 int ret;
3092 int slot;
3093
3094 leaf = path->nodes[0];
3095 slot = path->slots[0];
3096 while (1) {
3097 if (slot >= btrfs_header_nritems(leaf)) {
3098 ret = btrfs_next_leaf(rc->extent_root, path);
3099 if (ret < 0)
3100 return ret;
3101 BUG_ON(ret > 0);
3102 leaf = path->nodes[0];
3103 slot = path->slots[0];
3104 if (path_change)
3105 *path_change = 1;
3106 }
3107 btrfs_item_key_to_cpu(leaf, &key, slot);
3108 if (key.objectid != extent_key->objectid)
3109 return -ENOENT;
3110
3111 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3112 slot++;
3113 continue;
3114 }
3115 ref0 = btrfs_item_ptr(leaf, slot,
3116 struct btrfs_extent_ref_v0);
3117 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3118 break;
3119 }
3120 return 0;
3121 }
3122 #endif
3123
3124 /*
3125 * helper to add a tree block to the list.
3126 * the major work is getting the generation and level of the block
3127 */
3128 static int add_tree_block(struct reloc_control *rc,
3129 struct btrfs_key *extent_key,
3130 struct btrfs_path *path,
3131 struct rb_root *blocks)
3132 {
3133 struct extent_buffer *eb;
3134 struct btrfs_extent_item *ei;
3135 struct btrfs_tree_block_info *bi;
3136 struct tree_block *block;
3137 struct rb_node *rb_node;
3138 u32 item_size;
3139 int level = -1;
3140 int generation;
3141
3142 eb = path->nodes[0];
3143 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3144
3145 if (item_size >= sizeof(*ei) + sizeof(*bi)) {
3146 ei = btrfs_item_ptr(eb, path->slots[0],
3147 struct btrfs_extent_item);
3148 bi = (struct btrfs_tree_block_info *)(ei + 1);
3149 generation = btrfs_extent_generation(eb, ei);
3150 level = btrfs_tree_block_level(eb, bi);
3151 } else {
3152 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3153 u64 ref_owner;
3154 int ret;
3155
3156 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3157 ret = get_ref_objectid_v0(rc, path, extent_key,
3158 &ref_owner, NULL);
3159 if (ret < 0)
3160 return ret;
3161 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3162 level = (int)ref_owner;
3163 /* FIXME: get real generation */
3164 generation = 0;
3165 #else
3166 BUG();
3167 #endif
3168 }
3169
3170 btrfs_release_path(path);
3171
3172 BUG_ON(level == -1);
3173
3174 block = kmalloc(sizeof(*block), GFP_NOFS);
3175 if (!block)
3176 return -ENOMEM;
3177
3178 block->bytenr = extent_key->objectid;
3179 block->key.objectid = extent_key->offset;
3180 block->key.offset = generation;
3181 block->level = level;
3182 block->key_ready = 0;
3183
3184 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3185 if (rb_node)
3186 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3187
3188 return 0;
3189 }
3190
3191 /*
3192 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3193 */
3194 static int __add_tree_block(struct reloc_control *rc,
3195 u64 bytenr, u32 blocksize,
3196 struct rb_root *blocks)
3197 {
3198 struct btrfs_path *path;
3199 struct btrfs_key key;
3200 int ret;
3201
3202 if (tree_block_processed(bytenr, blocksize, rc))
3203 return 0;
3204
3205 if (tree_search(blocks, bytenr))
3206 return 0;
3207
3208 path = btrfs_alloc_path();
3209 if (!path)
3210 return -ENOMEM;
3211
3212 key.objectid = bytenr;
3213 key.type = BTRFS_EXTENT_ITEM_KEY;
3214 key.offset = blocksize;
3215
3216 path->search_commit_root = 1;
3217 path->skip_locking = 1;
3218 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3219 if (ret < 0)
3220 goto out;
3221 BUG_ON(ret);
3222
3223 btrfs_item_key_to_cpu(path->nodes[0], &key, path->slots[0]);
3224 ret = add_tree_block(rc, &key, path, blocks);
3225 out:
3226 btrfs_free_path(path);
3227 return ret;
3228 }
3229
3230 /*
3231 * helper to check if the block use full backrefs for pointers in it
3232 */
3233 static int block_use_full_backref(struct reloc_control *rc,
3234 struct extent_buffer *eb)
3235 {
3236 u64 flags;
3237 int ret;
3238
3239 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3240 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3241 return 1;
3242
3243 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3244 eb->start, eb->len, NULL, &flags);
3245 BUG_ON(ret);
3246
3247 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3248 ret = 1;
3249 else
3250 ret = 0;
3251 return ret;
3252 }
3253
3254 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3255 struct inode *inode, u64 ino)
3256 {
3257 struct btrfs_key key;
3258 struct btrfs_path *path;
3259 struct btrfs_root *root = fs_info->tree_root;
3260 struct btrfs_trans_handle *trans;
3261 unsigned long nr;
3262 int ret = 0;
3263
3264 if (inode)
3265 goto truncate;
3266
3267 key.objectid = ino;
3268 key.type = BTRFS_INODE_ITEM_KEY;
3269 key.offset = 0;
3270
3271 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3272 if (IS_ERR_OR_NULL(inode) || is_bad_inode(inode)) {
3273 if (inode && !IS_ERR(inode))
3274 iput(inode);
3275 return -ENOENT;
3276 }
3277
3278 truncate:
3279 path = btrfs_alloc_path();
3280 if (!path) {
3281 ret = -ENOMEM;
3282 goto out;
3283 }
3284
3285 trans = btrfs_join_transaction(root);
3286 if (IS_ERR(trans)) {
3287 btrfs_free_path(path);
3288 ret = PTR_ERR(trans);
3289 goto out;
3290 }
3291
3292 ret = btrfs_truncate_free_space_cache(root, trans, path, inode);
3293
3294 btrfs_free_path(path);
3295 nr = trans->blocks_used;
3296 btrfs_end_transaction(trans, root);
3297 btrfs_btree_balance_dirty(root, nr);
3298 out:
3299 iput(inode);
3300 return ret;
3301 }
3302
3303 /*
3304 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3305 * this function scans fs tree to find blocks reference the data extent
3306 */
3307 static int find_data_references(struct reloc_control *rc,
3308 struct btrfs_key *extent_key,
3309 struct extent_buffer *leaf,
3310 struct btrfs_extent_data_ref *ref,
3311 struct rb_root *blocks)
3312 {
3313 struct btrfs_path *path;
3314 struct tree_block *block;
3315 struct btrfs_root *root;
3316 struct btrfs_file_extent_item *fi;
3317 struct rb_node *rb_node;
3318 struct btrfs_key key;
3319 u64 ref_root;
3320 u64 ref_objectid;
3321 u64 ref_offset;
3322 u32 ref_count;
3323 u32 nritems;
3324 int err = 0;
3325 int added = 0;
3326 int counted;
3327 int ret;
3328
3329 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3330 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3331 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3332 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3333
3334 /*
3335 * This is an extent belonging to the free space cache, lets just delete
3336 * it and redo the search.
3337 */
3338 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3339 ret = delete_block_group_cache(rc->extent_root->fs_info,
3340 NULL, ref_objectid);
3341 if (ret != -ENOENT)
3342 return ret;
3343 ret = 0;
3344 }
3345
3346 path = btrfs_alloc_path();
3347 if (!path)
3348 return -ENOMEM;
3349 path->reada = 1;
3350
3351 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3352 if (IS_ERR(root)) {
3353 err = PTR_ERR(root);
3354 goto out;
3355 }
3356
3357 key.objectid = ref_objectid;
3358 key.type = BTRFS_EXTENT_DATA_KEY;
3359 if (ref_offset > ((u64)-1 << 32))
3360 key.offset = 0;
3361 else
3362 key.offset = ref_offset;
3363
3364 path->search_commit_root = 1;
3365 path->skip_locking = 1;
3366 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3367 if (ret < 0) {
3368 err = ret;
3369 goto out;
3370 }
3371
3372 leaf = path->nodes[0];
3373 nritems = btrfs_header_nritems(leaf);
3374 /*
3375 * the references in tree blocks that use full backrefs
3376 * are not counted in
3377 */
3378 if (block_use_full_backref(rc, leaf))
3379 counted = 0;
3380 else
3381 counted = 1;
3382 rb_node = tree_search(blocks, leaf->start);
3383 if (rb_node) {
3384 if (counted)
3385 added = 1;
3386 else
3387 path->slots[0] = nritems;
3388 }
3389
3390 while (ref_count > 0) {
3391 while (path->slots[0] >= nritems) {
3392 ret = btrfs_next_leaf(root, path);
3393 if (ret < 0) {
3394 err = ret;
3395 goto out;
3396 }
3397 if (ret > 0) {
3398 WARN_ON(1);
3399 goto out;
3400 }
3401
3402 leaf = path->nodes[0];
3403 nritems = btrfs_header_nritems(leaf);
3404 added = 0;
3405
3406 if (block_use_full_backref(rc, leaf))
3407 counted = 0;
3408 else
3409 counted = 1;
3410 rb_node = tree_search(blocks, leaf->start);
3411 if (rb_node) {
3412 if (counted)
3413 added = 1;
3414 else
3415 path->slots[0] = nritems;
3416 }
3417 }
3418
3419 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3420 if (key.objectid != ref_objectid ||
3421 key.type != BTRFS_EXTENT_DATA_KEY) {
3422 WARN_ON(1);
3423 break;
3424 }
3425
3426 fi = btrfs_item_ptr(leaf, path->slots[0],
3427 struct btrfs_file_extent_item);
3428
3429 if (btrfs_file_extent_type(leaf, fi) ==
3430 BTRFS_FILE_EXTENT_INLINE)
3431 goto next;
3432
3433 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3434 extent_key->objectid)
3435 goto next;
3436
3437 key.offset -= btrfs_file_extent_offset(leaf, fi);
3438 if (key.offset != ref_offset)
3439 goto next;
3440
3441 if (counted)
3442 ref_count--;
3443 if (added)
3444 goto next;
3445
3446 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3447 block = kmalloc(sizeof(*block), GFP_NOFS);
3448 if (!block) {
3449 err = -ENOMEM;
3450 break;
3451 }
3452 block->bytenr = leaf->start;
3453 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3454 block->level = 0;
3455 block->key_ready = 1;
3456 rb_node = tree_insert(blocks, block->bytenr,
3457 &block->rb_node);
3458 if (rb_node)
3459 backref_tree_panic(rb_node, -EEXIST,
3460 block->bytenr);
3461 }
3462 if (counted)
3463 added = 1;
3464 else
3465 path->slots[0] = nritems;
3466 next:
3467 path->slots[0]++;
3468
3469 }
3470 out:
3471 btrfs_free_path(path);
3472 return err;
3473 }
3474
3475 /*
3476 * hepler to find all tree blocks that reference a given data extent
3477 */
3478 static noinline_for_stack
3479 int add_data_references(struct reloc_control *rc,
3480 struct btrfs_key *extent_key,
3481 struct btrfs_path *path,
3482 struct rb_root *blocks)
3483 {
3484 struct btrfs_key key;
3485 struct extent_buffer *eb;
3486 struct btrfs_extent_data_ref *dref;
3487 struct btrfs_extent_inline_ref *iref;
3488 unsigned long ptr;
3489 unsigned long end;
3490 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3491 int ret;
3492 int err = 0;
3493
3494 eb = path->nodes[0];
3495 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3496 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3497 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3498 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3499 ptr = end;
3500 else
3501 #endif
3502 ptr += sizeof(struct btrfs_extent_item);
3503
3504 while (ptr < end) {
3505 iref = (struct btrfs_extent_inline_ref *)ptr;
3506 key.type = btrfs_extent_inline_ref_type(eb, iref);
3507 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3508 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3509 ret = __add_tree_block(rc, key.offset, blocksize,
3510 blocks);
3511 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3512 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3513 ret = find_data_references(rc, extent_key,
3514 eb, dref, blocks);
3515 } else {
3516 BUG();
3517 }
3518 ptr += btrfs_extent_inline_ref_size(key.type);
3519 }
3520 WARN_ON(ptr > end);
3521
3522 while (1) {
3523 cond_resched();
3524 eb = path->nodes[0];
3525 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3526 ret = btrfs_next_leaf(rc->extent_root, path);
3527 if (ret < 0) {
3528 err = ret;
3529 break;
3530 }
3531 if (ret > 0)
3532 break;
3533 eb = path->nodes[0];
3534 }
3535
3536 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3537 if (key.objectid != extent_key->objectid)
3538 break;
3539
3540 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3541 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3542 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3543 #else
3544 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3545 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3546 #endif
3547 ret = __add_tree_block(rc, key.offset, blocksize,
3548 blocks);
3549 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3550 dref = btrfs_item_ptr(eb, path->slots[0],
3551 struct btrfs_extent_data_ref);
3552 ret = find_data_references(rc, extent_key,
3553 eb, dref, blocks);
3554 } else {
3555 ret = 0;
3556 }
3557 if (ret) {
3558 err = ret;
3559 break;
3560 }
3561 path->slots[0]++;
3562 }
3563 btrfs_release_path(path);
3564 if (err)
3565 free_block_list(blocks);
3566 return err;
3567 }
3568
3569 /*
3570 * hepler to find next unprocessed extent
3571 */
3572 static noinline_for_stack
3573 int find_next_extent(struct btrfs_trans_handle *trans,
3574 struct reloc_control *rc, struct btrfs_path *path,
3575 struct btrfs_key *extent_key)
3576 {
3577 struct btrfs_key key;
3578 struct extent_buffer *leaf;
3579 u64 start, end, last;
3580 int ret;
3581
3582 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3583 while (1) {
3584 cond_resched();
3585 if (rc->search_start >= last) {
3586 ret = 1;
3587 break;
3588 }
3589
3590 key.objectid = rc->search_start;
3591 key.type = BTRFS_EXTENT_ITEM_KEY;
3592 key.offset = 0;
3593
3594 path->search_commit_root = 1;
3595 path->skip_locking = 1;
3596 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3597 0, 0);
3598 if (ret < 0)
3599 break;
3600 next:
3601 leaf = path->nodes[0];
3602 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3603 ret = btrfs_next_leaf(rc->extent_root, path);
3604 if (ret != 0)
3605 break;
3606 leaf = path->nodes[0];
3607 }
3608
3609 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3610 if (key.objectid >= last) {
3611 ret = 1;
3612 break;
3613 }
3614
3615 if (key.type != BTRFS_EXTENT_ITEM_KEY ||
3616 key.objectid + key.offset <= rc->search_start) {
3617 path->slots[0]++;
3618 goto next;
3619 }
3620
3621 ret = find_first_extent_bit(&rc->processed_blocks,
3622 key.objectid, &start, &end,
3623 EXTENT_DIRTY);
3624
3625 if (ret == 0 && start <= key.objectid) {
3626 btrfs_release_path(path);
3627 rc->search_start = end + 1;
3628 } else {
3629 rc->search_start = key.objectid + key.offset;
3630 memcpy(extent_key, &key, sizeof(key));
3631 return 0;
3632 }
3633 }
3634 btrfs_release_path(path);
3635 return ret;
3636 }
3637
3638 static void set_reloc_control(struct reloc_control *rc)
3639 {
3640 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3641
3642 mutex_lock(&fs_info->reloc_mutex);
3643 fs_info->reloc_ctl = rc;
3644 mutex_unlock(&fs_info->reloc_mutex);
3645 }
3646
3647 static void unset_reloc_control(struct reloc_control *rc)
3648 {
3649 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3650
3651 mutex_lock(&fs_info->reloc_mutex);
3652 fs_info->reloc_ctl = NULL;
3653 mutex_unlock(&fs_info->reloc_mutex);
3654 }
3655
3656 static int check_extent_flags(u64 flags)
3657 {
3658 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3659 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3660 return 1;
3661 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3662 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3663 return 1;
3664 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3665 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3666 return 1;
3667 return 0;
3668 }
3669
3670 static noinline_for_stack
3671 int prepare_to_relocate(struct reloc_control *rc)
3672 {
3673 struct btrfs_trans_handle *trans;
3674 int ret;
3675
3676 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root);
3677 if (!rc->block_rsv)
3678 return -ENOMEM;
3679
3680 /*
3681 * reserve some space for creating reloc trees.
3682 * btrfs_init_reloc_root will use them when there
3683 * is no reservation in transaction handle.
3684 */
3685 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3686 rc->extent_root->nodesize * 256);
3687 if (ret)
3688 return ret;
3689
3690 memset(&rc->cluster, 0, sizeof(rc->cluster));
3691 rc->search_start = rc->block_group->key.objectid;
3692 rc->extents_found = 0;
3693 rc->nodes_relocated = 0;
3694 rc->merging_rsv_size = 0;
3695
3696 rc->create_reloc_tree = 1;
3697 set_reloc_control(rc);
3698
3699 trans = btrfs_join_transaction(rc->extent_root);
3700 BUG_ON(IS_ERR(trans));
3701 btrfs_commit_transaction(trans, rc->extent_root);
3702 return 0;
3703 }
3704
3705 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3706 {
3707 struct rb_root blocks = RB_ROOT;
3708 struct btrfs_key key;
3709 struct btrfs_trans_handle *trans = NULL;
3710 struct btrfs_path *path;
3711 struct btrfs_extent_item *ei;
3712 unsigned long nr;
3713 u64 flags;
3714 u32 item_size;
3715 int ret;
3716 int err = 0;
3717 int progress = 0;
3718
3719 path = btrfs_alloc_path();
3720 if (!path)
3721 return -ENOMEM;
3722 path->reada = 1;
3723
3724 ret = prepare_to_relocate(rc);
3725 if (ret) {
3726 err = ret;
3727 goto out_free;
3728 }
3729
3730 while (1) {
3731 progress++;
3732 trans = btrfs_start_transaction(rc->extent_root, 0);
3733 BUG_ON(IS_ERR(trans));
3734 restart:
3735 if (update_backref_cache(trans, &rc->backref_cache)) {
3736 btrfs_end_transaction(trans, rc->extent_root);
3737 continue;
3738 }
3739
3740 ret = find_next_extent(trans, rc, path, &key);
3741 if (ret < 0)
3742 err = ret;
3743 if (ret != 0)
3744 break;
3745
3746 rc->extents_found++;
3747
3748 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3749 struct btrfs_extent_item);
3750 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3751 if (item_size >= sizeof(*ei)) {
3752 flags = btrfs_extent_flags(path->nodes[0], ei);
3753 ret = check_extent_flags(flags);
3754 BUG_ON(ret);
3755
3756 } else {
3757 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3758 u64 ref_owner;
3759 int path_change = 0;
3760
3761 BUG_ON(item_size !=
3762 sizeof(struct btrfs_extent_item_v0));
3763 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3764 &path_change);
3765 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3766 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3767 else
3768 flags = BTRFS_EXTENT_FLAG_DATA;
3769
3770 if (path_change) {
3771 btrfs_release_path(path);
3772
3773 path->search_commit_root = 1;
3774 path->skip_locking = 1;
3775 ret = btrfs_search_slot(NULL, rc->extent_root,
3776 &key, path, 0, 0);
3777 if (ret < 0) {
3778 err = ret;
3779 break;
3780 }
3781 BUG_ON(ret > 0);
3782 }
3783 #else
3784 BUG();
3785 #endif
3786 }
3787
3788 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3789 ret = add_tree_block(rc, &key, path, &blocks);
3790 } else if (rc->stage == UPDATE_DATA_PTRS &&
3791 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3792 ret = add_data_references(rc, &key, path, &blocks);
3793 } else {
3794 btrfs_release_path(path);
3795 ret = 0;
3796 }
3797 if (ret < 0) {
3798 err = ret;
3799 break;
3800 }
3801
3802 if (!RB_EMPTY_ROOT(&blocks)) {
3803 ret = relocate_tree_blocks(trans, rc, &blocks);
3804 if (ret < 0) {
3805 if (ret != -EAGAIN) {
3806 err = ret;
3807 break;
3808 }
3809 rc->extents_found--;
3810 rc->search_start = key.objectid;
3811 }
3812 }
3813
3814 ret = btrfs_block_rsv_check(rc->extent_root, rc->block_rsv, 5);
3815 if (ret < 0) {
3816 if (ret != -ENOSPC) {
3817 err = ret;
3818 WARN_ON(1);
3819 break;
3820 }
3821 rc->commit_transaction = 1;
3822 }
3823
3824 if (rc->commit_transaction) {
3825 rc->commit_transaction = 0;
3826 ret = btrfs_commit_transaction(trans, rc->extent_root);
3827 BUG_ON(ret);
3828 } else {
3829 nr = trans->blocks_used;
3830 btrfs_end_transaction_throttle(trans, rc->extent_root);
3831 btrfs_btree_balance_dirty(rc->extent_root, nr);
3832 }
3833 trans = NULL;
3834
3835 if (rc->stage == MOVE_DATA_EXTENTS &&
3836 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3837 rc->found_file_extent = 1;
3838 ret = relocate_data_extent(rc->data_inode,
3839 &key, &rc->cluster);
3840 if (ret < 0) {
3841 err = ret;
3842 break;
3843 }
3844 }
3845 }
3846 if (trans && progress && err == -ENOSPC) {
3847 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
3848 rc->block_group->flags);
3849 if (ret == 0) {
3850 err = 0;
3851 progress = 0;
3852 goto restart;
3853 }
3854 }
3855
3856 btrfs_release_path(path);
3857 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
3858 GFP_NOFS);
3859
3860 if (trans) {
3861 nr = trans->blocks_used;
3862 btrfs_end_transaction_throttle(trans, rc->extent_root);
3863 btrfs_btree_balance_dirty(rc->extent_root, nr);
3864 }
3865
3866 if (!err) {
3867 ret = relocate_file_extent_cluster(rc->data_inode,
3868 &rc->cluster);
3869 if (ret < 0)
3870 err = ret;
3871 }
3872
3873 rc->create_reloc_tree = 0;
3874 set_reloc_control(rc);
3875
3876 backref_cache_cleanup(&rc->backref_cache);
3877 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3878
3879 err = prepare_to_merge(rc, err);
3880
3881 merge_reloc_roots(rc);
3882
3883 rc->merge_reloc_tree = 0;
3884 unset_reloc_control(rc);
3885 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
3886
3887 /* get rid of pinned extents */
3888 trans = btrfs_join_transaction(rc->extent_root);
3889 if (IS_ERR(trans))
3890 err = PTR_ERR(trans);
3891 else
3892 btrfs_commit_transaction(trans, rc->extent_root);
3893 out_free:
3894 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
3895 btrfs_free_path(path);
3896 return err;
3897 }
3898
3899 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3900 struct btrfs_root *root, u64 objectid)
3901 {
3902 struct btrfs_path *path;
3903 struct btrfs_inode_item *item;
3904 struct extent_buffer *leaf;
3905 int ret;
3906
3907 path = btrfs_alloc_path();
3908 if (!path)
3909 return -ENOMEM;
3910
3911 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3912 if (ret)
3913 goto out;
3914
3915 leaf = path->nodes[0];
3916 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3917 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
3918 btrfs_set_inode_generation(leaf, item, 1);
3919 btrfs_set_inode_size(leaf, item, 0);
3920 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3921 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3922 BTRFS_INODE_PREALLOC);
3923 btrfs_mark_buffer_dirty(leaf);
3924 btrfs_release_path(path);
3925 out:
3926 btrfs_free_path(path);
3927 return ret;
3928 }
3929
3930 /*
3931 * helper to create inode for data relocation.
3932 * the inode is in data relocation tree and its link count is 0
3933 */
3934 static noinline_for_stack
3935 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3936 struct btrfs_block_group_cache *group)
3937 {
3938 struct inode *inode = NULL;
3939 struct btrfs_trans_handle *trans;
3940 struct btrfs_root *root;
3941 struct btrfs_key key;
3942 unsigned long nr;
3943 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
3944 int err = 0;
3945
3946 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
3947 if (IS_ERR(root))
3948 return ERR_CAST(root);
3949
3950 trans = btrfs_start_transaction(root, 6);
3951 if (IS_ERR(trans))
3952 return ERR_CAST(trans);
3953
3954 err = btrfs_find_free_objectid(root, &objectid);
3955 if (err)
3956 goto out;
3957
3958 err = __insert_orphan_inode(trans, root, objectid);
3959 BUG_ON(err);
3960
3961 key.objectid = objectid;
3962 key.type = BTRFS_INODE_ITEM_KEY;
3963 key.offset = 0;
3964 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
3965 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
3966 BTRFS_I(inode)->index_cnt = group->key.objectid;
3967
3968 err = btrfs_orphan_add(trans, inode);
3969 out:
3970 nr = trans->blocks_used;
3971 btrfs_end_transaction(trans, root);
3972 btrfs_btree_balance_dirty(root, nr);
3973 if (err) {
3974 if (inode)
3975 iput(inode);
3976 inode = ERR_PTR(err);
3977 }
3978 return inode;
3979 }
3980
3981 static struct reloc_control *alloc_reloc_control(void)
3982 {
3983 struct reloc_control *rc;
3984
3985 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3986 if (!rc)
3987 return NULL;
3988
3989 INIT_LIST_HEAD(&rc->reloc_roots);
3990 backref_cache_init(&rc->backref_cache);
3991 mapping_tree_init(&rc->reloc_root_tree);
3992 extent_io_tree_init(&rc->processed_blocks, NULL);
3993 return rc;
3994 }
3995
3996 /*
3997 * function to relocate all extents in a block group.
3998 */
3999 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4000 {
4001 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4002 struct reloc_control *rc;
4003 struct inode *inode;
4004 struct btrfs_path *path;
4005 int ret;
4006 int rw = 0;
4007 int err = 0;
4008
4009 rc = alloc_reloc_control();
4010 if (!rc)
4011 return -ENOMEM;
4012
4013 rc->extent_root = extent_root;
4014
4015 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4016 BUG_ON(!rc->block_group);
4017
4018 if (!rc->block_group->ro) {
4019 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4020 if (ret) {
4021 err = ret;
4022 goto out;
4023 }
4024 rw = 1;
4025 }
4026
4027 path = btrfs_alloc_path();
4028 if (!path) {
4029 err = -ENOMEM;
4030 goto out;
4031 }
4032
4033 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4034 path);
4035 btrfs_free_path(path);
4036
4037 if (!IS_ERR(inode))
4038 ret = delete_block_group_cache(fs_info, inode, 0);
4039 else
4040 ret = PTR_ERR(inode);
4041
4042 if (ret && ret != -ENOENT) {
4043 err = ret;
4044 goto out;
4045 }
4046
4047 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4048 if (IS_ERR(rc->data_inode)) {
4049 err = PTR_ERR(rc->data_inode);
4050 rc->data_inode = NULL;
4051 goto out;
4052 }
4053
4054 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4055 (unsigned long long)rc->block_group->key.objectid,
4056 (unsigned long long)rc->block_group->flags);
4057
4058 btrfs_start_delalloc_inodes(fs_info->tree_root, 0);
4059 btrfs_wait_ordered_extents(fs_info->tree_root, 0, 0);
4060
4061 while (1) {
4062 mutex_lock(&fs_info->cleaner_mutex);
4063
4064 btrfs_clean_old_snapshots(fs_info->tree_root);
4065 ret = relocate_block_group(rc);
4066
4067 mutex_unlock(&fs_info->cleaner_mutex);
4068 if (ret < 0) {
4069 err = ret;
4070 goto out;
4071 }
4072
4073 if (rc->extents_found == 0)
4074 break;
4075
4076 printk(KERN_INFO "btrfs: found %llu extents\n",
4077 (unsigned long long)rc->extents_found);
4078
4079 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4080 btrfs_wait_ordered_range(rc->data_inode, 0, (u64)-1);
4081 invalidate_mapping_pages(rc->data_inode->i_mapping,
4082 0, -1);
4083 rc->stage = UPDATE_DATA_PTRS;
4084 }
4085 }
4086
4087 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4088 rc->block_group->key.objectid,
4089 rc->block_group->key.objectid +
4090 rc->block_group->key.offset - 1);
4091
4092 WARN_ON(rc->block_group->pinned > 0);
4093 WARN_ON(rc->block_group->reserved > 0);
4094 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4095 out:
4096 if (err && rw)
4097 btrfs_set_block_group_rw(extent_root, rc->block_group);
4098 iput(rc->data_inode);
4099 btrfs_put_block_group(rc->block_group);
4100 kfree(rc);
4101 return err;
4102 }
4103
4104 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4105 {
4106 struct btrfs_trans_handle *trans;
4107 int ret, err;
4108
4109 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4110 if (IS_ERR(trans))
4111 return PTR_ERR(trans);
4112
4113 memset(&root->root_item.drop_progress, 0,
4114 sizeof(root->root_item.drop_progress));
4115 root->root_item.drop_level = 0;
4116 btrfs_set_root_refs(&root->root_item, 0);
4117 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4118 &root->root_key, &root->root_item);
4119
4120 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4121 if (err)
4122 return err;
4123 return ret;
4124 }
4125
4126 /*
4127 * recover relocation interrupted by system crash.
4128 *
4129 * this function resumes merging reloc trees with corresponding fs trees.
4130 * this is important for keeping the sharing of tree blocks
4131 */
4132 int btrfs_recover_relocation(struct btrfs_root *root)
4133 {
4134 LIST_HEAD(reloc_roots);
4135 struct btrfs_key key;
4136 struct btrfs_root *fs_root;
4137 struct btrfs_root *reloc_root;
4138 struct btrfs_path *path;
4139 struct extent_buffer *leaf;
4140 struct reloc_control *rc = NULL;
4141 struct btrfs_trans_handle *trans;
4142 int ret;
4143 int err = 0;
4144
4145 path = btrfs_alloc_path();
4146 if (!path)
4147 return -ENOMEM;
4148 path->reada = -1;
4149
4150 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4151 key.type = BTRFS_ROOT_ITEM_KEY;
4152 key.offset = (u64)-1;
4153
4154 while (1) {
4155 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4156 path, 0, 0);
4157 if (ret < 0) {
4158 err = ret;
4159 goto out;
4160 }
4161 if (ret > 0) {
4162 if (path->slots[0] == 0)
4163 break;
4164 path->slots[0]--;
4165 }
4166 leaf = path->nodes[0];
4167 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4168 btrfs_release_path(path);
4169
4170 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4171 key.type != BTRFS_ROOT_ITEM_KEY)
4172 break;
4173
4174 reloc_root = btrfs_read_fs_root_no_radix(root, &key);
4175 if (IS_ERR(reloc_root)) {
4176 err = PTR_ERR(reloc_root);
4177 goto out;
4178 }
4179
4180 list_add(&reloc_root->root_list, &reloc_roots);
4181
4182 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4183 fs_root = read_fs_root(root->fs_info,
4184 reloc_root->root_key.offset);
4185 if (IS_ERR(fs_root)) {
4186 ret = PTR_ERR(fs_root);
4187 if (ret != -ENOENT) {
4188 err = ret;
4189 goto out;
4190 }
4191 ret = mark_garbage_root(reloc_root);
4192 if (ret < 0) {
4193 err = ret;
4194 goto out;
4195 }
4196 }
4197 }
4198
4199 if (key.offset == 0)
4200 break;
4201
4202 key.offset--;
4203 }
4204 btrfs_release_path(path);
4205
4206 if (list_empty(&reloc_roots))
4207 goto out;
4208
4209 rc = alloc_reloc_control();
4210 if (!rc) {
4211 err = -ENOMEM;
4212 goto out;
4213 }
4214
4215 rc->extent_root = root->fs_info->extent_root;
4216
4217 set_reloc_control(rc);
4218
4219 trans = btrfs_join_transaction(rc->extent_root);
4220 if (IS_ERR(trans)) {
4221 unset_reloc_control(rc);
4222 err = PTR_ERR(trans);
4223 goto out_free;
4224 }
4225
4226 rc->merge_reloc_tree = 1;
4227
4228 while (!list_empty(&reloc_roots)) {
4229 reloc_root = list_entry(reloc_roots.next,
4230 struct btrfs_root, root_list);
4231 list_del(&reloc_root->root_list);
4232
4233 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4234 list_add_tail(&reloc_root->root_list,
4235 &rc->reloc_roots);
4236 continue;
4237 }
4238
4239 fs_root = read_fs_root(root->fs_info,
4240 reloc_root->root_key.offset);
4241 if (IS_ERR(fs_root)) {
4242 err = PTR_ERR(fs_root);
4243 goto out_free;
4244 }
4245
4246 err = __add_reloc_root(reloc_root);
4247 BUG_ON(err < 0); /* -ENOMEM or logic error */
4248 fs_root->reloc_root = reloc_root;
4249 }
4250
4251 err = btrfs_commit_transaction(trans, rc->extent_root);
4252 if (err)
4253 goto out_free;
4254
4255 merge_reloc_roots(rc);
4256
4257 unset_reloc_control(rc);
4258
4259 trans = btrfs_join_transaction(rc->extent_root);
4260 if (IS_ERR(trans))
4261 err = PTR_ERR(trans);
4262 else
4263 err = btrfs_commit_transaction(trans, rc->extent_root);
4264 out_free:
4265 kfree(rc);
4266 out:
4267 while (!list_empty(&reloc_roots)) {
4268 reloc_root = list_entry(reloc_roots.next,
4269 struct btrfs_root, root_list);
4270 list_del(&reloc_root->root_list);
4271 free_extent_buffer(reloc_root->node);
4272 free_extent_buffer(reloc_root->commit_root);
4273 kfree(reloc_root);
4274 }
4275 btrfs_free_path(path);
4276
4277 if (err == 0) {
4278 /* cleanup orphan inode in data relocation tree */
4279 fs_root = read_fs_root(root->fs_info,
4280 BTRFS_DATA_RELOC_TREE_OBJECTID);
4281 if (IS_ERR(fs_root))
4282 err = PTR_ERR(fs_root);
4283 else
4284 err = btrfs_orphan_cleanup(fs_root);
4285 }
4286 return err;
4287 }
4288
4289 /*
4290 * helper to add ordered checksum for data relocation.
4291 *
4292 * cloning checksum properly handles the nodatasum extents.
4293 * it also saves CPU time to re-calculate the checksum.
4294 */
4295 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4296 {
4297 struct btrfs_ordered_sum *sums;
4298 struct btrfs_sector_sum *sector_sum;
4299 struct btrfs_ordered_extent *ordered;
4300 struct btrfs_root *root = BTRFS_I(inode)->root;
4301 size_t offset;
4302 int ret;
4303 u64 disk_bytenr;
4304 LIST_HEAD(list);
4305
4306 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4307 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4308
4309 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4310 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4311 disk_bytenr + len - 1, &list, 0);
4312 if (ret)
4313 goto out;
4314
4315 while (!list_empty(&list)) {
4316 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4317 list_del_init(&sums->list);
4318
4319 sector_sum = sums->sums;
4320 sums->bytenr = ordered->start;
4321
4322 offset = 0;
4323 while (offset < sums->len) {
4324 sector_sum->bytenr += ordered->start - disk_bytenr;
4325 sector_sum++;
4326 offset += root->sectorsize;
4327 }
4328
4329 btrfs_add_ordered_sum(inode, ordered, sums);
4330 }
4331 out:
4332 btrfs_put_ordered_extent(ordered);
4333 return ret;
4334 }
4335
4336 void btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4337 struct btrfs_root *root, struct extent_buffer *buf,
4338 struct extent_buffer *cow)
4339 {
4340 struct reloc_control *rc;
4341 struct backref_node *node;
4342 int first_cow = 0;
4343 int level;
4344 int ret;
4345
4346 rc = root->fs_info->reloc_ctl;
4347 if (!rc)
4348 return;
4349
4350 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4351 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4352
4353 level = btrfs_header_level(buf);
4354 if (btrfs_header_generation(buf) <=
4355 btrfs_root_last_snapshot(&root->root_item))
4356 first_cow = 1;
4357
4358 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4359 rc->create_reloc_tree) {
4360 WARN_ON(!first_cow && level == 0);
4361
4362 node = rc->backref_cache.path[level];
4363 BUG_ON(node->bytenr != buf->start &&
4364 node->new_bytenr != buf->start);
4365
4366 drop_node_buffer(node);
4367 extent_buffer_get(cow);
4368 node->eb = cow;
4369 node->new_bytenr = cow->start;
4370
4371 if (!node->pending) {
4372 list_move_tail(&node->list,
4373 &rc->backref_cache.pending[level]);
4374 node->pending = 1;
4375 }
4376
4377 if (first_cow)
4378 __mark_block_processed(rc, node);
4379
4380 if (first_cow && level > 0)
4381 rc->nodes_relocated += buf->len;
4382 }
4383
4384 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS) {
4385 ret = replace_file_extents(trans, rc, root, cow);
4386 BUG_ON(ret);
4387 }
4388 }
4389
4390 /*
4391 * called before creating snapshot. it calculates metadata reservation
4392 * requried for relocating tree blocks in the snapshot
4393 */
4394 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4395 struct btrfs_pending_snapshot *pending,
4396 u64 *bytes_to_reserve)
4397 {
4398 struct btrfs_root *root;
4399 struct reloc_control *rc;
4400
4401 root = pending->root;
4402 if (!root->reloc_root)
4403 return;
4404
4405 rc = root->fs_info->reloc_ctl;
4406 if (!rc->merge_reloc_tree)
4407 return;
4408
4409 root = root->reloc_root;
4410 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4411 /*
4412 * relocation is in the stage of merging trees. the space
4413 * used by merging a reloc tree is twice the size of
4414 * relocated tree nodes in the worst case. half for cowing
4415 * the reloc tree, half for cowing the fs tree. the space
4416 * used by cowing the reloc tree will be freed after the
4417 * tree is dropped. if we create snapshot, cowing the fs
4418 * tree may use more space than it frees. so we need
4419 * reserve extra space.
4420 */
4421 *bytes_to_reserve += rc->nodes_relocated;
4422 }
4423
4424 /*
4425 * called after snapshot is created. migrate block reservation
4426 * and create reloc root for the newly created snapshot
4427 */
4428 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4429 struct btrfs_pending_snapshot *pending)
4430 {
4431 struct btrfs_root *root = pending->root;
4432 struct btrfs_root *reloc_root;
4433 struct btrfs_root *new_root;
4434 struct reloc_control *rc;
4435 int ret;
4436
4437 if (!root->reloc_root)
4438 return 0;
4439
4440 rc = root->fs_info->reloc_ctl;
4441 rc->merging_rsv_size += rc->nodes_relocated;
4442
4443 if (rc->merge_reloc_tree) {
4444 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4445 rc->block_rsv,
4446 rc->nodes_relocated);
4447 if (ret)
4448 return ret;
4449 }
4450
4451 new_root = pending->snap;
4452 reloc_root = create_reloc_root(trans, root->reloc_root,
4453 new_root->root_key.objectid);
4454 if (IS_ERR(reloc_root))
4455 return PTR_ERR(reloc_root);
4456
4457 ret = __add_reloc_root(reloc_root);
4458 BUG_ON(ret < 0);
4459 new_root->reloc_root = reloc_root;
4460
4461 if (rc->create_reloc_tree)
4462 ret = clone_backref_node(trans, rc, root, reloc_root);
4463 return ret;
4464 }
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