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