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Merge remote-tracking branches 'regmap/fix/doc' and 'regmap/fix/mmio' into regmap...
[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 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
330 {
331
332 struct btrfs_fs_info *fs_info = NULL;
333 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
334 rb_node);
335 if (bnode->root)
336 fs_info = bnode->root->fs_info;
337 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
338 "found at offset %llu\n", bytenr);
339 }
340
341 /*
342 * walk up backref nodes until reach node presents tree root
343 */
344 static struct backref_node *walk_up_backref(struct backref_node *node,
345 struct backref_edge *edges[],
346 int *index)
347 {
348 struct backref_edge *edge;
349 int idx = *index;
350
351 while (!list_empty(&node->upper)) {
352 edge = list_entry(node->upper.next,
353 struct backref_edge, list[LOWER]);
354 edges[idx++] = edge;
355 node = edge->node[UPPER];
356 }
357 BUG_ON(node->detached);
358 *index = idx;
359 return node;
360 }
361
362 /*
363 * walk down backref nodes to find start of next reference path
364 */
365 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
366 int *index)
367 {
368 struct backref_edge *edge;
369 struct backref_node *lower;
370 int idx = *index;
371
372 while (idx > 0) {
373 edge = edges[idx - 1];
374 lower = edge->node[LOWER];
375 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
376 idx--;
377 continue;
378 }
379 edge = list_entry(edge->list[LOWER].next,
380 struct backref_edge, list[LOWER]);
381 edges[idx - 1] = edge;
382 *index = idx;
383 return edge->node[UPPER];
384 }
385 *index = 0;
386 return NULL;
387 }
388
389 static void unlock_node_buffer(struct backref_node *node)
390 {
391 if (node->locked) {
392 btrfs_tree_unlock(node->eb);
393 node->locked = 0;
394 }
395 }
396
397 static void drop_node_buffer(struct backref_node *node)
398 {
399 if (node->eb) {
400 unlock_node_buffer(node);
401 free_extent_buffer(node->eb);
402 node->eb = NULL;
403 }
404 }
405
406 static void drop_backref_node(struct backref_cache *tree,
407 struct backref_node *node)
408 {
409 BUG_ON(!list_empty(&node->upper));
410
411 drop_node_buffer(node);
412 list_del(&node->list);
413 list_del(&node->lower);
414 if (!RB_EMPTY_NODE(&node->rb_node))
415 rb_erase(&node->rb_node, &tree->rb_root);
416 free_backref_node(tree, node);
417 }
418
419 /*
420 * remove a backref node from the backref cache
421 */
422 static void remove_backref_node(struct backref_cache *cache,
423 struct backref_node *node)
424 {
425 struct backref_node *upper;
426 struct backref_edge *edge;
427
428 if (!node)
429 return;
430
431 BUG_ON(!node->lowest && !node->detached);
432 while (!list_empty(&node->upper)) {
433 edge = list_entry(node->upper.next, struct backref_edge,
434 list[LOWER]);
435 upper = edge->node[UPPER];
436 list_del(&edge->list[LOWER]);
437 list_del(&edge->list[UPPER]);
438 free_backref_edge(cache, edge);
439
440 if (RB_EMPTY_NODE(&upper->rb_node)) {
441 BUG_ON(!list_empty(&node->upper));
442 drop_backref_node(cache, node);
443 node = upper;
444 node->lowest = 1;
445 continue;
446 }
447 /*
448 * add the node to leaf node list if no other
449 * child block cached.
450 */
451 if (list_empty(&upper->lower)) {
452 list_add_tail(&upper->lower, &cache->leaves);
453 upper->lowest = 1;
454 }
455 }
456
457 drop_backref_node(cache, node);
458 }
459
460 static void update_backref_node(struct backref_cache *cache,
461 struct backref_node *node, u64 bytenr)
462 {
463 struct rb_node *rb_node;
464 rb_erase(&node->rb_node, &cache->rb_root);
465 node->bytenr = bytenr;
466 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
467 if (rb_node)
468 backref_tree_panic(rb_node, -EEXIST, bytenr);
469 }
470
471 /*
472 * update backref cache after a transaction commit
473 */
474 static int update_backref_cache(struct btrfs_trans_handle *trans,
475 struct backref_cache *cache)
476 {
477 struct backref_node *node;
478 int level = 0;
479
480 if (cache->last_trans == 0) {
481 cache->last_trans = trans->transid;
482 return 0;
483 }
484
485 if (cache->last_trans == trans->transid)
486 return 0;
487
488 /*
489 * detached nodes are used to avoid unnecessary backref
490 * lookup. transaction commit changes the extent tree.
491 * so the detached nodes are no longer useful.
492 */
493 while (!list_empty(&cache->detached)) {
494 node = list_entry(cache->detached.next,
495 struct backref_node, list);
496 remove_backref_node(cache, node);
497 }
498
499 while (!list_empty(&cache->changed)) {
500 node = list_entry(cache->changed.next,
501 struct backref_node, list);
502 list_del_init(&node->list);
503 BUG_ON(node->pending);
504 update_backref_node(cache, node, node->new_bytenr);
505 }
506
507 /*
508 * some nodes can be left in the pending list if there were
509 * errors during processing the pending nodes.
510 */
511 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
512 list_for_each_entry(node, &cache->pending[level], list) {
513 BUG_ON(!node->pending);
514 if (node->bytenr == node->new_bytenr)
515 continue;
516 update_backref_node(cache, node, node->new_bytenr);
517 }
518 }
519
520 cache->last_trans = 0;
521 return 1;
522 }
523
524
525 static int should_ignore_root(struct btrfs_root *root)
526 {
527 struct btrfs_root *reloc_root;
528
529 if (!root->ref_cows)
530 return 0;
531
532 reloc_root = root->reloc_root;
533 if (!reloc_root)
534 return 0;
535
536 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
537 root->fs_info->running_transaction->transid - 1)
538 return 0;
539 /*
540 * if there is reloc tree and it was created in previous
541 * transaction backref lookup can find the reloc tree,
542 * so backref node for the fs tree root is useless for
543 * relocation.
544 */
545 return 1;
546 }
547 /*
548 * find reloc tree by address of tree root
549 */
550 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
551 u64 bytenr)
552 {
553 struct rb_node *rb_node;
554 struct mapping_node *node;
555 struct btrfs_root *root = NULL;
556
557 spin_lock(&rc->reloc_root_tree.lock);
558 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
559 if (rb_node) {
560 node = rb_entry(rb_node, struct mapping_node, rb_node);
561 root = (struct btrfs_root *)node->data;
562 }
563 spin_unlock(&rc->reloc_root_tree.lock);
564 return root;
565 }
566
567 static int is_cowonly_root(u64 root_objectid)
568 {
569 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
570 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
571 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
572 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
573 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
574 root_objectid == BTRFS_CSUM_TREE_OBJECTID)
575 return 1;
576 return 0;
577 }
578
579 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
580 u64 root_objectid)
581 {
582 struct btrfs_key key;
583
584 key.objectid = root_objectid;
585 key.type = BTRFS_ROOT_ITEM_KEY;
586 if (is_cowonly_root(root_objectid))
587 key.offset = 0;
588 else
589 key.offset = (u64)-1;
590
591 return btrfs_get_fs_root(fs_info, &key, false);
592 }
593
594 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
595 static noinline_for_stack
596 struct btrfs_root *find_tree_root(struct reloc_control *rc,
597 struct extent_buffer *leaf,
598 struct btrfs_extent_ref_v0 *ref0)
599 {
600 struct btrfs_root *root;
601 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
602 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
603
604 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
605
606 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
607 BUG_ON(IS_ERR(root));
608
609 if (root->ref_cows &&
610 generation != btrfs_root_generation(&root->root_item))
611 return NULL;
612
613 return root;
614 }
615 #endif
616
617 static noinline_for_stack
618 int find_inline_backref(struct extent_buffer *leaf, int slot,
619 unsigned long *ptr, unsigned long *end)
620 {
621 struct btrfs_key key;
622 struct btrfs_extent_item *ei;
623 struct btrfs_tree_block_info *bi;
624 u32 item_size;
625
626 btrfs_item_key_to_cpu(leaf, &key, slot);
627
628 item_size = btrfs_item_size_nr(leaf, slot);
629 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
630 if (item_size < sizeof(*ei)) {
631 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
632 return 1;
633 }
634 #endif
635 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
636 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
637 BTRFS_EXTENT_FLAG_TREE_BLOCK));
638
639 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
640 item_size <= sizeof(*ei) + sizeof(*bi)) {
641 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
642 return 1;
643 }
644 if (key.type == BTRFS_METADATA_ITEM_KEY &&
645 item_size <= sizeof(*ei)) {
646 WARN_ON(item_size < sizeof(*ei));
647 return 1;
648 }
649
650 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
651 bi = (struct btrfs_tree_block_info *)(ei + 1);
652 *ptr = (unsigned long)(bi + 1);
653 } else {
654 *ptr = (unsigned long)(ei + 1);
655 }
656 *end = (unsigned long)ei + item_size;
657 return 0;
658 }
659
660 /*
661 * build backref tree for a given tree block. root of the backref tree
662 * corresponds the tree block, leaves of the backref tree correspond
663 * roots of b-trees that reference the tree block.
664 *
665 * the basic idea of this function is check backrefs of a given block
666 * to find upper level blocks that refernece the block, and then check
667 * bakcrefs of these upper level blocks recursively. the recursion stop
668 * when tree root is reached or backrefs for the block is cached.
669 *
670 * NOTE: if we find backrefs for a block are cached, we know backrefs
671 * for all upper level blocks that directly/indirectly reference the
672 * block are also cached.
673 */
674 static noinline_for_stack
675 struct backref_node *build_backref_tree(struct reloc_control *rc,
676 struct btrfs_key *node_key,
677 int level, u64 bytenr)
678 {
679 struct backref_cache *cache = &rc->backref_cache;
680 struct btrfs_path *path1;
681 struct btrfs_path *path2;
682 struct extent_buffer *eb;
683 struct btrfs_root *root;
684 struct backref_node *cur;
685 struct backref_node *upper;
686 struct backref_node *lower;
687 struct backref_node *node = NULL;
688 struct backref_node *exist = NULL;
689 struct backref_edge *edge;
690 struct rb_node *rb_node;
691 struct btrfs_key key;
692 unsigned long end;
693 unsigned long ptr;
694 LIST_HEAD(list);
695 LIST_HEAD(useless);
696 int cowonly;
697 int ret;
698 int err = 0;
699 bool need_check = true;
700
701 path1 = btrfs_alloc_path();
702 path2 = btrfs_alloc_path();
703 if (!path1 || !path2) {
704 err = -ENOMEM;
705 goto out;
706 }
707 path1->reada = 1;
708 path2->reada = 2;
709
710 node = alloc_backref_node(cache);
711 if (!node) {
712 err = -ENOMEM;
713 goto out;
714 }
715
716 node->bytenr = bytenr;
717 node->level = level;
718 node->lowest = 1;
719 cur = node;
720 again:
721 end = 0;
722 ptr = 0;
723 key.objectid = cur->bytenr;
724 key.type = BTRFS_METADATA_ITEM_KEY;
725 key.offset = (u64)-1;
726
727 path1->search_commit_root = 1;
728 path1->skip_locking = 1;
729 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
730 0, 0);
731 if (ret < 0) {
732 err = ret;
733 goto out;
734 }
735 BUG_ON(!ret || !path1->slots[0]);
736
737 path1->slots[0]--;
738
739 WARN_ON(cur->checked);
740 if (!list_empty(&cur->upper)) {
741 /*
742 * the backref was added previously when processing
743 * backref of type BTRFS_TREE_BLOCK_REF_KEY
744 */
745 BUG_ON(!list_is_singular(&cur->upper));
746 edge = list_entry(cur->upper.next, struct backref_edge,
747 list[LOWER]);
748 BUG_ON(!list_empty(&edge->list[UPPER]));
749 exist = edge->node[UPPER];
750 /*
751 * add the upper level block to pending list if we need
752 * check its backrefs
753 */
754 if (!exist->checked)
755 list_add_tail(&edge->list[UPPER], &list);
756 } else {
757 exist = NULL;
758 }
759
760 while (1) {
761 cond_resched();
762 eb = path1->nodes[0];
763
764 if (ptr >= end) {
765 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
766 ret = btrfs_next_leaf(rc->extent_root, path1);
767 if (ret < 0) {
768 err = ret;
769 goto out;
770 }
771 if (ret > 0)
772 break;
773 eb = path1->nodes[0];
774 }
775
776 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
777 if (key.objectid != cur->bytenr) {
778 WARN_ON(exist);
779 break;
780 }
781
782 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
783 key.type == BTRFS_METADATA_ITEM_KEY) {
784 ret = find_inline_backref(eb, path1->slots[0],
785 &ptr, &end);
786 if (ret)
787 goto next;
788 }
789 }
790
791 if (ptr < end) {
792 /* update key for inline back ref */
793 struct btrfs_extent_inline_ref *iref;
794 iref = (struct btrfs_extent_inline_ref *)ptr;
795 key.type = btrfs_extent_inline_ref_type(eb, iref);
796 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
797 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
798 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
799 }
800
801 if (exist &&
802 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
803 exist->owner == key.offset) ||
804 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
805 exist->bytenr == key.offset))) {
806 exist = NULL;
807 goto next;
808 }
809
810 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
811 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
812 key.type == BTRFS_EXTENT_REF_V0_KEY) {
813 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
814 struct btrfs_extent_ref_v0 *ref0;
815 ref0 = btrfs_item_ptr(eb, path1->slots[0],
816 struct btrfs_extent_ref_v0);
817 if (key.objectid == key.offset) {
818 root = find_tree_root(rc, eb, ref0);
819 if (root && !should_ignore_root(root))
820 cur->root = root;
821 else
822 list_add(&cur->list, &useless);
823 break;
824 }
825 if (is_cowonly_root(btrfs_ref_root_v0(eb,
826 ref0)))
827 cur->cowonly = 1;
828 }
829 #else
830 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
831 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
832 #endif
833 if (key.objectid == key.offset) {
834 /*
835 * only root blocks of reloc trees use
836 * backref of this type.
837 */
838 root = find_reloc_root(rc, cur->bytenr);
839 BUG_ON(!root);
840 cur->root = root;
841 break;
842 }
843
844 edge = alloc_backref_edge(cache);
845 if (!edge) {
846 err = -ENOMEM;
847 goto out;
848 }
849 rb_node = tree_search(&cache->rb_root, key.offset);
850 if (!rb_node) {
851 upper = alloc_backref_node(cache);
852 if (!upper) {
853 free_backref_edge(cache, edge);
854 err = -ENOMEM;
855 goto out;
856 }
857 upper->bytenr = key.offset;
858 upper->level = cur->level + 1;
859 /*
860 * backrefs for the upper level block isn't
861 * cached, add the block to pending list
862 */
863 list_add_tail(&edge->list[UPPER], &list);
864 } else {
865 upper = rb_entry(rb_node, struct backref_node,
866 rb_node);
867 BUG_ON(!upper->checked);
868 INIT_LIST_HEAD(&edge->list[UPPER]);
869 }
870 list_add_tail(&edge->list[LOWER], &cur->upper);
871 edge->node[LOWER] = cur;
872 edge->node[UPPER] = upper;
873
874 goto next;
875 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
876 goto next;
877 }
878
879 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
880 root = read_fs_root(rc->extent_root->fs_info, key.offset);
881 if (IS_ERR(root)) {
882 err = PTR_ERR(root);
883 goto out;
884 }
885
886 if (!root->ref_cows)
887 cur->cowonly = 1;
888
889 if (btrfs_root_level(&root->root_item) == cur->level) {
890 /* tree root */
891 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
892 cur->bytenr);
893 if (should_ignore_root(root))
894 list_add(&cur->list, &useless);
895 else
896 cur->root = root;
897 break;
898 }
899
900 level = cur->level + 1;
901
902 /*
903 * searching the tree to find upper level blocks
904 * reference the block.
905 */
906 path2->search_commit_root = 1;
907 path2->skip_locking = 1;
908 path2->lowest_level = level;
909 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
910 path2->lowest_level = 0;
911 if (ret < 0) {
912 err = ret;
913 goto out;
914 }
915 if (ret > 0 && path2->slots[level] > 0)
916 path2->slots[level]--;
917
918 eb = path2->nodes[level];
919 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
920 cur->bytenr);
921
922 lower = cur;
923 need_check = true;
924 for (; level < BTRFS_MAX_LEVEL; level++) {
925 if (!path2->nodes[level]) {
926 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
927 lower->bytenr);
928 if (should_ignore_root(root))
929 list_add(&lower->list, &useless);
930 else
931 lower->root = root;
932 break;
933 }
934
935 edge = alloc_backref_edge(cache);
936 if (!edge) {
937 err = -ENOMEM;
938 goto out;
939 }
940
941 eb = path2->nodes[level];
942 rb_node = tree_search(&cache->rb_root, eb->start);
943 if (!rb_node) {
944 upper = alloc_backref_node(cache);
945 if (!upper) {
946 free_backref_edge(cache, edge);
947 err = -ENOMEM;
948 goto out;
949 }
950 upper->bytenr = eb->start;
951 upper->owner = btrfs_header_owner(eb);
952 upper->level = lower->level + 1;
953 if (!root->ref_cows)
954 upper->cowonly = 1;
955
956 /*
957 * if we know the block isn't shared
958 * we can void checking its backrefs.
959 */
960 if (btrfs_block_can_be_shared(root, eb))
961 upper->checked = 0;
962 else
963 upper->checked = 1;
964
965 /*
966 * add the block to pending list if we
967 * need check its backrefs, we only do this once
968 * while walking up a tree as we will catch
969 * anything else later on.
970 */
971 if (!upper->checked && need_check) {
972 need_check = false;
973 list_add_tail(&edge->list[UPPER],
974 &list);
975 } else
976 INIT_LIST_HEAD(&edge->list[UPPER]);
977 } else {
978 upper = rb_entry(rb_node, struct backref_node,
979 rb_node);
980 BUG_ON(!upper->checked);
981 INIT_LIST_HEAD(&edge->list[UPPER]);
982 if (!upper->owner)
983 upper->owner = btrfs_header_owner(eb);
984 }
985 list_add_tail(&edge->list[LOWER], &lower->upper);
986 edge->node[LOWER] = lower;
987 edge->node[UPPER] = upper;
988
989 if (rb_node)
990 break;
991 lower = upper;
992 upper = NULL;
993 }
994 btrfs_release_path(path2);
995 next:
996 if (ptr < end) {
997 ptr += btrfs_extent_inline_ref_size(key.type);
998 if (ptr >= end) {
999 WARN_ON(ptr > end);
1000 ptr = 0;
1001 end = 0;
1002 }
1003 }
1004 if (ptr >= end)
1005 path1->slots[0]++;
1006 }
1007 btrfs_release_path(path1);
1008
1009 cur->checked = 1;
1010 WARN_ON(exist);
1011
1012 /* the pending list isn't empty, take the first block to process */
1013 if (!list_empty(&list)) {
1014 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1015 list_del_init(&edge->list[UPPER]);
1016 cur = edge->node[UPPER];
1017 goto again;
1018 }
1019
1020 /*
1021 * everything goes well, connect backref nodes and insert backref nodes
1022 * into the cache.
1023 */
1024 BUG_ON(!node->checked);
1025 cowonly = node->cowonly;
1026 if (!cowonly) {
1027 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1028 &node->rb_node);
1029 if (rb_node)
1030 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1031 list_add_tail(&node->lower, &cache->leaves);
1032 }
1033
1034 list_for_each_entry(edge, &node->upper, list[LOWER])
1035 list_add_tail(&edge->list[UPPER], &list);
1036
1037 while (!list_empty(&list)) {
1038 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1039 list_del_init(&edge->list[UPPER]);
1040 upper = edge->node[UPPER];
1041 if (upper->detached) {
1042 list_del(&edge->list[LOWER]);
1043 lower = edge->node[LOWER];
1044 free_backref_edge(cache, edge);
1045 if (list_empty(&lower->upper))
1046 list_add(&lower->list, &useless);
1047 continue;
1048 }
1049
1050 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1051 if (upper->lowest) {
1052 list_del_init(&upper->lower);
1053 upper->lowest = 0;
1054 }
1055
1056 list_add_tail(&edge->list[UPPER], &upper->lower);
1057 continue;
1058 }
1059
1060 BUG_ON(!upper->checked);
1061 BUG_ON(cowonly != upper->cowonly);
1062 if (!cowonly) {
1063 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1064 &upper->rb_node);
1065 if (rb_node)
1066 backref_tree_panic(rb_node, -EEXIST,
1067 upper->bytenr);
1068 }
1069
1070 list_add_tail(&edge->list[UPPER], &upper->lower);
1071
1072 list_for_each_entry(edge, &upper->upper, list[LOWER])
1073 list_add_tail(&edge->list[UPPER], &list);
1074 }
1075 /*
1076 * process useless backref nodes. backref nodes for tree leaves
1077 * are deleted from the cache. backref nodes for upper level
1078 * tree blocks are left in the cache to avoid unnecessary backref
1079 * lookup.
1080 */
1081 while (!list_empty(&useless)) {
1082 upper = list_entry(useless.next, struct backref_node, list);
1083 list_del_init(&upper->list);
1084 BUG_ON(!list_empty(&upper->upper));
1085 if (upper == node)
1086 node = NULL;
1087 if (upper->lowest) {
1088 list_del_init(&upper->lower);
1089 upper->lowest = 0;
1090 }
1091 while (!list_empty(&upper->lower)) {
1092 edge = list_entry(upper->lower.next,
1093 struct backref_edge, list[UPPER]);
1094 list_del(&edge->list[UPPER]);
1095 list_del(&edge->list[LOWER]);
1096 lower = edge->node[LOWER];
1097 free_backref_edge(cache, edge);
1098
1099 if (list_empty(&lower->upper))
1100 list_add(&lower->list, &useless);
1101 }
1102 __mark_block_processed(rc, upper);
1103 if (upper->level > 0) {
1104 list_add(&upper->list, &cache->detached);
1105 upper->detached = 1;
1106 } else {
1107 rb_erase(&upper->rb_node, &cache->rb_root);
1108 free_backref_node(cache, upper);
1109 }
1110 }
1111 out:
1112 btrfs_free_path(path1);
1113 btrfs_free_path(path2);
1114 if (err) {
1115 while (!list_empty(&useless)) {
1116 lower = list_entry(useless.next,
1117 struct backref_node, upper);
1118 list_del_init(&lower->upper);
1119 }
1120 upper = node;
1121 INIT_LIST_HEAD(&list);
1122 while (upper) {
1123 if (RB_EMPTY_NODE(&upper->rb_node)) {
1124 list_splice_tail(&upper->upper, &list);
1125 free_backref_node(cache, upper);
1126 }
1127
1128 if (list_empty(&list))
1129 break;
1130
1131 edge = list_entry(list.next, struct backref_edge,
1132 list[LOWER]);
1133 list_del(&edge->list[LOWER]);
1134 upper = edge->node[UPPER];
1135 free_backref_edge(cache, edge);
1136 }
1137 return ERR_PTR(err);
1138 }
1139 BUG_ON(node && node->detached);
1140 return node;
1141 }
1142
1143 /*
1144 * helper to add backref node for the newly created snapshot.
1145 * the backref node is created by cloning backref node that
1146 * corresponds to root of source tree
1147 */
1148 static int clone_backref_node(struct btrfs_trans_handle *trans,
1149 struct reloc_control *rc,
1150 struct btrfs_root *src,
1151 struct btrfs_root *dest)
1152 {
1153 struct btrfs_root *reloc_root = src->reloc_root;
1154 struct backref_cache *cache = &rc->backref_cache;
1155 struct backref_node *node = NULL;
1156 struct backref_node *new_node;
1157 struct backref_edge *edge;
1158 struct backref_edge *new_edge;
1159 struct rb_node *rb_node;
1160
1161 if (cache->last_trans > 0)
1162 update_backref_cache(trans, cache);
1163
1164 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1165 if (rb_node) {
1166 node = rb_entry(rb_node, struct backref_node, rb_node);
1167 if (node->detached)
1168 node = NULL;
1169 else
1170 BUG_ON(node->new_bytenr != reloc_root->node->start);
1171 }
1172
1173 if (!node) {
1174 rb_node = tree_search(&cache->rb_root,
1175 reloc_root->commit_root->start);
1176 if (rb_node) {
1177 node = rb_entry(rb_node, struct backref_node,
1178 rb_node);
1179 BUG_ON(node->detached);
1180 }
1181 }
1182
1183 if (!node)
1184 return 0;
1185
1186 new_node = alloc_backref_node(cache);
1187 if (!new_node)
1188 return -ENOMEM;
1189
1190 new_node->bytenr = dest->node->start;
1191 new_node->level = node->level;
1192 new_node->lowest = node->lowest;
1193 new_node->checked = 1;
1194 new_node->root = dest;
1195
1196 if (!node->lowest) {
1197 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1198 new_edge = alloc_backref_edge(cache);
1199 if (!new_edge)
1200 goto fail;
1201
1202 new_edge->node[UPPER] = new_node;
1203 new_edge->node[LOWER] = edge->node[LOWER];
1204 list_add_tail(&new_edge->list[UPPER],
1205 &new_node->lower);
1206 }
1207 } else {
1208 list_add_tail(&new_node->lower, &cache->leaves);
1209 }
1210
1211 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1212 &new_node->rb_node);
1213 if (rb_node)
1214 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1215
1216 if (!new_node->lowest) {
1217 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1218 list_add_tail(&new_edge->list[LOWER],
1219 &new_edge->node[LOWER]->upper);
1220 }
1221 }
1222 return 0;
1223 fail:
1224 while (!list_empty(&new_node->lower)) {
1225 new_edge = list_entry(new_node->lower.next,
1226 struct backref_edge, list[UPPER]);
1227 list_del(&new_edge->list[UPPER]);
1228 free_backref_edge(cache, new_edge);
1229 }
1230 free_backref_node(cache, new_node);
1231 return -ENOMEM;
1232 }
1233
1234 /*
1235 * helper to add 'address of tree root -> reloc tree' mapping
1236 */
1237 static int __must_check __add_reloc_root(struct btrfs_root *root)
1238 {
1239 struct rb_node *rb_node;
1240 struct mapping_node *node;
1241 struct reloc_control *rc = root->fs_info->reloc_ctl;
1242
1243 node = kmalloc(sizeof(*node), GFP_NOFS);
1244 if (!node)
1245 return -ENOMEM;
1246
1247 node->bytenr = root->node->start;
1248 node->data = root;
1249
1250 spin_lock(&rc->reloc_root_tree.lock);
1251 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1252 node->bytenr, &node->rb_node);
1253 spin_unlock(&rc->reloc_root_tree.lock);
1254 if (rb_node) {
1255 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1256 "for start=%llu while inserting into relocation "
1257 "tree\n", node->bytenr);
1258 kfree(node);
1259 return -EEXIST;
1260 }
1261
1262 list_add_tail(&root->root_list, &rc->reloc_roots);
1263 return 0;
1264 }
1265
1266 /*
1267 * helper to update/delete the 'address of tree root -> reloc tree'
1268 * mapping
1269 */
1270 static int __update_reloc_root(struct btrfs_root *root, int del)
1271 {
1272 struct rb_node *rb_node;
1273 struct mapping_node *node = NULL;
1274 struct reloc_control *rc = root->fs_info->reloc_ctl;
1275
1276 spin_lock(&rc->reloc_root_tree.lock);
1277 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1278 root->commit_root->start);
1279 if (rb_node) {
1280 node = rb_entry(rb_node, struct mapping_node, rb_node);
1281 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1282 }
1283 spin_unlock(&rc->reloc_root_tree.lock);
1284
1285 if (!node)
1286 return 0;
1287 BUG_ON((struct btrfs_root *)node->data != root);
1288
1289 if (!del) {
1290 spin_lock(&rc->reloc_root_tree.lock);
1291 node->bytenr = root->node->start;
1292 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1293 node->bytenr, &node->rb_node);
1294 spin_unlock(&rc->reloc_root_tree.lock);
1295 if (rb_node)
1296 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1297 } else {
1298 spin_lock(&root->fs_info->trans_lock);
1299 list_del_init(&root->root_list);
1300 spin_unlock(&root->fs_info->trans_lock);
1301 kfree(node);
1302 }
1303 return 0;
1304 }
1305
1306 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1307 struct btrfs_root *root, u64 objectid)
1308 {
1309 struct btrfs_root *reloc_root;
1310 struct extent_buffer *eb;
1311 struct btrfs_root_item *root_item;
1312 struct btrfs_key root_key;
1313 u64 last_snap = 0;
1314 int ret;
1315
1316 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1317 BUG_ON(!root_item);
1318
1319 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1320 root_key.type = BTRFS_ROOT_ITEM_KEY;
1321 root_key.offset = objectid;
1322
1323 if (root->root_key.objectid == objectid) {
1324 /* called by btrfs_init_reloc_root */
1325 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1326 BTRFS_TREE_RELOC_OBJECTID);
1327 BUG_ON(ret);
1328
1329 last_snap = btrfs_root_last_snapshot(&root->root_item);
1330 btrfs_set_root_last_snapshot(&root->root_item,
1331 trans->transid - 1);
1332 } else {
1333 /*
1334 * called by btrfs_reloc_post_snapshot_hook.
1335 * the source tree is a reloc tree, all tree blocks
1336 * modified after it was created have RELOC flag
1337 * set in their headers. so it's OK to not update
1338 * the 'last_snapshot'.
1339 */
1340 ret = btrfs_copy_root(trans, root, root->node, &eb,
1341 BTRFS_TREE_RELOC_OBJECTID);
1342 BUG_ON(ret);
1343 }
1344
1345 memcpy(root_item, &root->root_item, sizeof(*root_item));
1346 btrfs_set_root_bytenr(root_item, eb->start);
1347 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1348 btrfs_set_root_generation(root_item, trans->transid);
1349
1350 if (root->root_key.objectid == objectid) {
1351 btrfs_set_root_refs(root_item, 0);
1352 memset(&root_item->drop_progress, 0,
1353 sizeof(struct btrfs_disk_key));
1354 root_item->drop_level = 0;
1355 /*
1356 * abuse rtransid, it is safe because it is impossible to
1357 * receive data into a relocation tree.
1358 */
1359 btrfs_set_root_rtransid(root_item, last_snap);
1360 btrfs_set_root_otransid(root_item, trans->transid);
1361 }
1362
1363 btrfs_tree_unlock(eb);
1364 free_extent_buffer(eb);
1365
1366 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1367 &root_key, root_item);
1368 BUG_ON(ret);
1369 kfree(root_item);
1370
1371 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1372 BUG_ON(IS_ERR(reloc_root));
1373 reloc_root->last_trans = trans->transid;
1374 return reloc_root;
1375 }
1376
1377 /*
1378 * create reloc tree for a given fs tree. reloc tree is just a
1379 * snapshot of the fs tree with special root objectid.
1380 */
1381 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1382 struct btrfs_root *root)
1383 {
1384 struct btrfs_root *reloc_root;
1385 struct reloc_control *rc = root->fs_info->reloc_ctl;
1386 struct btrfs_block_rsv *rsv;
1387 int clear_rsv = 0;
1388 int ret;
1389
1390 if (root->reloc_root) {
1391 reloc_root = root->reloc_root;
1392 reloc_root->last_trans = trans->transid;
1393 return 0;
1394 }
1395
1396 if (!rc || !rc->create_reloc_tree ||
1397 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1398 return 0;
1399
1400 if (!trans->reloc_reserved) {
1401 rsv = trans->block_rsv;
1402 trans->block_rsv = rc->block_rsv;
1403 clear_rsv = 1;
1404 }
1405 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1406 if (clear_rsv)
1407 trans->block_rsv = rsv;
1408
1409 ret = __add_reloc_root(reloc_root);
1410 BUG_ON(ret < 0);
1411 root->reloc_root = reloc_root;
1412 return 0;
1413 }
1414
1415 /*
1416 * update root item of reloc tree
1417 */
1418 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1419 struct btrfs_root *root)
1420 {
1421 struct btrfs_root *reloc_root;
1422 struct btrfs_root_item *root_item;
1423 int del = 0;
1424 int ret;
1425
1426 if (!root->reloc_root)
1427 goto out;
1428
1429 reloc_root = root->reloc_root;
1430 root_item = &reloc_root->root_item;
1431
1432 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1433 btrfs_root_refs(root_item) == 0) {
1434 root->reloc_root = NULL;
1435 del = 1;
1436 }
1437
1438 __update_reloc_root(reloc_root, del);
1439
1440 if (reloc_root->commit_root != reloc_root->node) {
1441 btrfs_set_root_node(root_item, reloc_root->node);
1442 free_extent_buffer(reloc_root->commit_root);
1443 reloc_root->commit_root = btrfs_root_node(reloc_root);
1444 }
1445
1446 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1447 &reloc_root->root_key, root_item);
1448 BUG_ON(ret);
1449
1450 out:
1451 return 0;
1452 }
1453
1454 /*
1455 * helper to find first cached inode with inode number >= objectid
1456 * in a subvolume
1457 */
1458 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1459 {
1460 struct rb_node *node;
1461 struct rb_node *prev;
1462 struct btrfs_inode *entry;
1463 struct inode *inode;
1464
1465 spin_lock(&root->inode_lock);
1466 again:
1467 node = root->inode_tree.rb_node;
1468 prev = NULL;
1469 while (node) {
1470 prev = node;
1471 entry = rb_entry(node, struct btrfs_inode, rb_node);
1472
1473 if (objectid < btrfs_ino(&entry->vfs_inode))
1474 node = node->rb_left;
1475 else if (objectid > btrfs_ino(&entry->vfs_inode))
1476 node = node->rb_right;
1477 else
1478 break;
1479 }
1480 if (!node) {
1481 while (prev) {
1482 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1483 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1484 node = prev;
1485 break;
1486 }
1487 prev = rb_next(prev);
1488 }
1489 }
1490 while (node) {
1491 entry = rb_entry(node, struct btrfs_inode, rb_node);
1492 inode = igrab(&entry->vfs_inode);
1493 if (inode) {
1494 spin_unlock(&root->inode_lock);
1495 return inode;
1496 }
1497
1498 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1499 if (cond_resched_lock(&root->inode_lock))
1500 goto again;
1501
1502 node = rb_next(node);
1503 }
1504 spin_unlock(&root->inode_lock);
1505 return NULL;
1506 }
1507
1508 static int in_block_group(u64 bytenr,
1509 struct btrfs_block_group_cache *block_group)
1510 {
1511 if (bytenr >= block_group->key.objectid &&
1512 bytenr < block_group->key.objectid + block_group->key.offset)
1513 return 1;
1514 return 0;
1515 }
1516
1517 /*
1518 * get new location of data
1519 */
1520 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1521 u64 bytenr, u64 num_bytes)
1522 {
1523 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1524 struct btrfs_path *path;
1525 struct btrfs_file_extent_item *fi;
1526 struct extent_buffer *leaf;
1527 int ret;
1528
1529 path = btrfs_alloc_path();
1530 if (!path)
1531 return -ENOMEM;
1532
1533 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1534 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1535 bytenr, 0);
1536 if (ret < 0)
1537 goto out;
1538 if (ret > 0) {
1539 ret = -ENOENT;
1540 goto out;
1541 }
1542
1543 leaf = path->nodes[0];
1544 fi = btrfs_item_ptr(leaf, path->slots[0],
1545 struct btrfs_file_extent_item);
1546
1547 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1548 btrfs_file_extent_compression(leaf, fi) ||
1549 btrfs_file_extent_encryption(leaf, fi) ||
1550 btrfs_file_extent_other_encoding(leaf, fi));
1551
1552 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1553 ret = -EINVAL;
1554 goto out;
1555 }
1556
1557 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1558 ret = 0;
1559 out:
1560 btrfs_free_path(path);
1561 return ret;
1562 }
1563
1564 /*
1565 * update file extent items in the tree leaf to point to
1566 * the new locations.
1567 */
1568 static noinline_for_stack
1569 int replace_file_extents(struct btrfs_trans_handle *trans,
1570 struct reloc_control *rc,
1571 struct btrfs_root *root,
1572 struct extent_buffer *leaf)
1573 {
1574 struct btrfs_key key;
1575 struct btrfs_file_extent_item *fi;
1576 struct inode *inode = NULL;
1577 u64 parent;
1578 u64 bytenr;
1579 u64 new_bytenr = 0;
1580 u64 num_bytes;
1581 u64 end;
1582 u32 nritems;
1583 u32 i;
1584 int ret = 0;
1585 int first = 1;
1586 int dirty = 0;
1587
1588 if (rc->stage != UPDATE_DATA_PTRS)
1589 return 0;
1590
1591 /* reloc trees always use full backref */
1592 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1593 parent = leaf->start;
1594 else
1595 parent = 0;
1596
1597 nritems = btrfs_header_nritems(leaf);
1598 for (i = 0; i < nritems; i++) {
1599 cond_resched();
1600 btrfs_item_key_to_cpu(leaf, &key, i);
1601 if (key.type != BTRFS_EXTENT_DATA_KEY)
1602 continue;
1603 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1604 if (btrfs_file_extent_type(leaf, fi) ==
1605 BTRFS_FILE_EXTENT_INLINE)
1606 continue;
1607 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1608 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1609 if (bytenr == 0)
1610 continue;
1611 if (!in_block_group(bytenr, rc->block_group))
1612 continue;
1613
1614 /*
1615 * if we are modifying block in fs tree, wait for readpage
1616 * to complete and drop the extent cache
1617 */
1618 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1619 if (first) {
1620 inode = find_next_inode(root, key.objectid);
1621 first = 0;
1622 } else if (inode && btrfs_ino(inode) < key.objectid) {
1623 btrfs_add_delayed_iput(inode);
1624 inode = find_next_inode(root, key.objectid);
1625 }
1626 if (inode && btrfs_ino(inode) == key.objectid) {
1627 end = key.offset +
1628 btrfs_file_extent_num_bytes(leaf, fi);
1629 WARN_ON(!IS_ALIGNED(key.offset,
1630 root->sectorsize));
1631 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1632 end--;
1633 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1634 key.offset, end);
1635 if (!ret)
1636 continue;
1637
1638 btrfs_drop_extent_cache(inode, key.offset, end,
1639 1);
1640 unlock_extent(&BTRFS_I(inode)->io_tree,
1641 key.offset, end);
1642 }
1643 }
1644
1645 ret = get_new_location(rc->data_inode, &new_bytenr,
1646 bytenr, num_bytes);
1647 if (ret) {
1648 /*
1649 * Don't have to abort since we've not changed anything
1650 * in the file extent yet.
1651 */
1652 break;
1653 }
1654
1655 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1656 dirty = 1;
1657
1658 key.offset -= btrfs_file_extent_offset(leaf, fi);
1659 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1660 num_bytes, parent,
1661 btrfs_header_owner(leaf),
1662 key.objectid, key.offset, 1);
1663 if (ret) {
1664 btrfs_abort_transaction(trans, root, ret);
1665 break;
1666 }
1667
1668 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1669 parent, btrfs_header_owner(leaf),
1670 key.objectid, key.offset, 1);
1671 if (ret) {
1672 btrfs_abort_transaction(trans, root, ret);
1673 break;
1674 }
1675 }
1676 if (dirty)
1677 btrfs_mark_buffer_dirty(leaf);
1678 if (inode)
1679 btrfs_add_delayed_iput(inode);
1680 return ret;
1681 }
1682
1683 static noinline_for_stack
1684 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1685 struct btrfs_path *path, int level)
1686 {
1687 struct btrfs_disk_key key1;
1688 struct btrfs_disk_key key2;
1689 btrfs_node_key(eb, &key1, slot);
1690 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1691 return memcmp(&key1, &key2, sizeof(key1));
1692 }
1693
1694 /*
1695 * try to replace tree blocks in fs tree with the new blocks
1696 * in reloc tree. tree blocks haven't been modified since the
1697 * reloc tree was create can be replaced.
1698 *
1699 * if a block was replaced, level of the block + 1 is returned.
1700 * if no block got replaced, 0 is returned. if there are other
1701 * errors, a negative error number is returned.
1702 */
1703 static noinline_for_stack
1704 int replace_path(struct btrfs_trans_handle *trans,
1705 struct btrfs_root *dest, struct btrfs_root *src,
1706 struct btrfs_path *path, struct btrfs_key *next_key,
1707 int lowest_level, int max_level)
1708 {
1709 struct extent_buffer *eb;
1710 struct extent_buffer *parent;
1711 struct btrfs_key key;
1712 u64 old_bytenr;
1713 u64 new_bytenr;
1714 u64 old_ptr_gen;
1715 u64 new_ptr_gen;
1716 u64 last_snapshot;
1717 u32 blocksize;
1718 int cow = 0;
1719 int level;
1720 int ret;
1721 int slot;
1722
1723 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1724 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1725
1726 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1727 again:
1728 slot = path->slots[lowest_level];
1729 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1730
1731 eb = btrfs_lock_root_node(dest);
1732 btrfs_set_lock_blocking(eb);
1733 level = btrfs_header_level(eb);
1734
1735 if (level < lowest_level) {
1736 btrfs_tree_unlock(eb);
1737 free_extent_buffer(eb);
1738 return 0;
1739 }
1740
1741 if (cow) {
1742 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1743 BUG_ON(ret);
1744 }
1745 btrfs_set_lock_blocking(eb);
1746
1747 if (next_key) {
1748 next_key->objectid = (u64)-1;
1749 next_key->type = (u8)-1;
1750 next_key->offset = (u64)-1;
1751 }
1752
1753 parent = eb;
1754 while (1) {
1755 level = btrfs_header_level(parent);
1756 BUG_ON(level < lowest_level);
1757
1758 ret = btrfs_bin_search(parent, &key, level, &slot);
1759 if (ret && slot > 0)
1760 slot--;
1761
1762 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1763 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1764
1765 old_bytenr = btrfs_node_blockptr(parent, slot);
1766 blocksize = btrfs_level_size(dest, level - 1);
1767 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1768
1769 if (level <= max_level) {
1770 eb = path->nodes[level];
1771 new_bytenr = btrfs_node_blockptr(eb,
1772 path->slots[level]);
1773 new_ptr_gen = btrfs_node_ptr_generation(eb,
1774 path->slots[level]);
1775 } else {
1776 new_bytenr = 0;
1777 new_ptr_gen = 0;
1778 }
1779
1780 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1781 ret = level;
1782 break;
1783 }
1784
1785 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1786 memcmp_node_keys(parent, slot, path, level)) {
1787 if (level <= lowest_level) {
1788 ret = 0;
1789 break;
1790 }
1791
1792 eb = read_tree_block(dest, old_bytenr, blocksize,
1793 old_ptr_gen);
1794 if (!eb || !extent_buffer_uptodate(eb)) {
1795 ret = (!eb) ? -ENOMEM : -EIO;
1796 free_extent_buffer(eb);
1797 break;
1798 }
1799 btrfs_tree_lock(eb);
1800 if (cow) {
1801 ret = btrfs_cow_block(trans, dest, eb, parent,
1802 slot, &eb);
1803 BUG_ON(ret);
1804 }
1805 btrfs_set_lock_blocking(eb);
1806
1807 btrfs_tree_unlock(parent);
1808 free_extent_buffer(parent);
1809
1810 parent = eb;
1811 continue;
1812 }
1813
1814 if (!cow) {
1815 btrfs_tree_unlock(parent);
1816 free_extent_buffer(parent);
1817 cow = 1;
1818 goto again;
1819 }
1820
1821 btrfs_node_key_to_cpu(path->nodes[level], &key,
1822 path->slots[level]);
1823 btrfs_release_path(path);
1824
1825 path->lowest_level = level;
1826 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1827 path->lowest_level = 0;
1828 BUG_ON(ret);
1829
1830 /*
1831 * swap blocks in fs tree and reloc tree.
1832 */
1833 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1834 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1835 btrfs_mark_buffer_dirty(parent);
1836
1837 btrfs_set_node_blockptr(path->nodes[level],
1838 path->slots[level], old_bytenr);
1839 btrfs_set_node_ptr_generation(path->nodes[level],
1840 path->slots[level], old_ptr_gen);
1841 btrfs_mark_buffer_dirty(path->nodes[level]);
1842
1843 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1844 path->nodes[level]->start,
1845 src->root_key.objectid, level - 1, 0,
1846 1);
1847 BUG_ON(ret);
1848 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1849 0, dest->root_key.objectid, level - 1,
1850 0, 1);
1851 BUG_ON(ret);
1852
1853 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1854 path->nodes[level]->start,
1855 src->root_key.objectid, level - 1, 0,
1856 1);
1857 BUG_ON(ret);
1858
1859 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1860 0, dest->root_key.objectid, level - 1,
1861 0, 1);
1862 BUG_ON(ret);
1863
1864 btrfs_unlock_up_safe(path, 0);
1865
1866 ret = level;
1867 break;
1868 }
1869 btrfs_tree_unlock(parent);
1870 free_extent_buffer(parent);
1871 return ret;
1872 }
1873
1874 /*
1875 * helper to find next relocated block in reloc tree
1876 */
1877 static noinline_for_stack
1878 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1879 int *level)
1880 {
1881 struct extent_buffer *eb;
1882 int i;
1883 u64 last_snapshot;
1884 u32 nritems;
1885
1886 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1887
1888 for (i = 0; i < *level; i++) {
1889 free_extent_buffer(path->nodes[i]);
1890 path->nodes[i] = NULL;
1891 }
1892
1893 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1894 eb = path->nodes[i];
1895 nritems = btrfs_header_nritems(eb);
1896 while (path->slots[i] + 1 < nritems) {
1897 path->slots[i]++;
1898 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1899 last_snapshot)
1900 continue;
1901
1902 *level = i;
1903 return 0;
1904 }
1905 free_extent_buffer(path->nodes[i]);
1906 path->nodes[i] = NULL;
1907 }
1908 return 1;
1909 }
1910
1911 /*
1912 * walk down reloc tree to find relocated block of lowest level
1913 */
1914 static noinline_for_stack
1915 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1916 int *level)
1917 {
1918 struct extent_buffer *eb = NULL;
1919 int i;
1920 u64 bytenr;
1921 u64 ptr_gen = 0;
1922 u64 last_snapshot;
1923 u32 blocksize;
1924 u32 nritems;
1925
1926 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1927
1928 for (i = *level; i > 0; i--) {
1929 eb = path->nodes[i];
1930 nritems = btrfs_header_nritems(eb);
1931 while (path->slots[i] < nritems) {
1932 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1933 if (ptr_gen > last_snapshot)
1934 break;
1935 path->slots[i]++;
1936 }
1937 if (path->slots[i] >= nritems) {
1938 if (i == *level)
1939 break;
1940 *level = i + 1;
1941 return 0;
1942 }
1943 if (i == 1) {
1944 *level = i;
1945 return 0;
1946 }
1947
1948 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1949 blocksize = btrfs_level_size(root, i - 1);
1950 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1951 if (!eb || !extent_buffer_uptodate(eb)) {
1952 free_extent_buffer(eb);
1953 return -EIO;
1954 }
1955 BUG_ON(btrfs_header_level(eb) != i - 1);
1956 path->nodes[i - 1] = eb;
1957 path->slots[i - 1] = 0;
1958 }
1959 return 1;
1960 }
1961
1962 /*
1963 * invalidate extent cache for file extents whose key in range of
1964 * [min_key, max_key)
1965 */
1966 static int invalidate_extent_cache(struct btrfs_root *root,
1967 struct btrfs_key *min_key,
1968 struct btrfs_key *max_key)
1969 {
1970 struct inode *inode = NULL;
1971 u64 objectid;
1972 u64 start, end;
1973 u64 ino;
1974
1975 objectid = min_key->objectid;
1976 while (1) {
1977 cond_resched();
1978 iput(inode);
1979
1980 if (objectid > max_key->objectid)
1981 break;
1982
1983 inode = find_next_inode(root, objectid);
1984 if (!inode)
1985 break;
1986 ino = btrfs_ino(inode);
1987
1988 if (ino > max_key->objectid) {
1989 iput(inode);
1990 break;
1991 }
1992
1993 objectid = ino + 1;
1994 if (!S_ISREG(inode->i_mode))
1995 continue;
1996
1997 if (unlikely(min_key->objectid == ino)) {
1998 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1999 continue;
2000 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2001 start = 0;
2002 else {
2003 start = min_key->offset;
2004 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2005 }
2006 } else {
2007 start = 0;
2008 }
2009
2010 if (unlikely(max_key->objectid == ino)) {
2011 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2012 continue;
2013 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2014 end = (u64)-1;
2015 } else {
2016 if (max_key->offset == 0)
2017 continue;
2018 end = max_key->offset;
2019 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2020 end--;
2021 }
2022 } else {
2023 end = (u64)-1;
2024 }
2025
2026 /* the lock_extent waits for readpage to complete */
2027 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2028 btrfs_drop_extent_cache(inode, start, end, 1);
2029 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2030 }
2031 return 0;
2032 }
2033
2034 static int find_next_key(struct btrfs_path *path, int level,
2035 struct btrfs_key *key)
2036
2037 {
2038 while (level < BTRFS_MAX_LEVEL) {
2039 if (!path->nodes[level])
2040 break;
2041 if (path->slots[level] + 1 <
2042 btrfs_header_nritems(path->nodes[level])) {
2043 btrfs_node_key_to_cpu(path->nodes[level], key,
2044 path->slots[level] + 1);
2045 return 0;
2046 }
2047 level++;
2048 }
2049 return 1;
2050 }
2051
2052 /*
2053 * merge the relocated tree blocks in reloc tree with corresponding
2054 * fs tree.
2055 */
2056 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2057 struct btrfs_root *root)
2058 {
2059 LIST_HEAD(inode_list);
2060 struct btrfs_key key;
2061 struct btrfs_key next_key;
2062 struct btrfs_trans_handle *trans = NULL;
2063 struct btrfs_root *reloc_root;
2064 struct btrfs_root_item *root_item;
2065 struct btrfs_path *path;
2066 struct extent_buffer *leaf;
2067 int level;
2068 int max_level;
2069 int replaced = 0;
2070 int ret;
2071 int err = 0;
2072 u32 min_reserved;
2073
2074 path = btrfs_alloc_path();
2075 if (!path)
2076 return -ENOMEM;
2077 path->reada = 1;
2078
2079 reloc_root = root->reloc_root;
2080 root_item = &reloc_root->root_item;
2081
2082 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2083 level = btrfs_root_level(root_item);
2084 extent_buffer_get(reloc_root->node);
2085 path->nodes[level] = reloc_root->node;
2086 path->slots[level] = 0;
2087 } else {
2088 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2089
2090 level = root_item->drop_level;
2091 BUG_ON(level == 0);
2092 path->lowest_level = level;
2093 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2094 path->lowest_level = 0;
2095 if (ret < 0) {
2096 btrfs_free_path(path);
2097 return ret;
2098 }
2099
2100 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2101 path->slots[level]);
2102 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2103
2104 btrfs_unlock_up_safe(path, 0);
2105 }
2106
2107 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2108 memset(&next_key, 0, sizeof(next_key));
2109
2110 while (1) {
2111 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2112 BTRFS_RESERVE_FLUSH_ALL);
2113 if (ret) {
2114 err = ret;
2115 goto out;
2116 }
2117 trans = btrfs_start_transaction(root, 0);
2118 if (IS_ERR(trans)) {
2119 err = PTR_ERR(trans);
2120 trans = NULL;
2121 goto out;
2122 }
2123 trans->block_rsv = rc->block_rsv;
2124
2125 replaced = 0;
2126 max_level = level;
2127
2128 ret = walk_down_reloc_tree(reloc_root, path, &level);
2129 if (ret < 0) {
2130 err = ret;
2131 goto out;
2132 }
2133 if (ret > 0)
2134 break;
2135
2136 if (!find_next_key(path, level, &key) &&
2137 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2138 ret = 0;
2139 } else {
2140 ret = replace_path(trans, root, reloc_root, path,
2141 &next_key, level, max_level);
2142 }
2143 if (ret < 0) {
2144 err = ret;
2145 goto out;
2146 }
2147
2148 if (ret > 0) {
2149 level = ret;
2150 btrfs_node_key_to_cpu(path->nodes[level], &key,
2151 path->slots[level]);
2152 replaced = 1;
2153 }
2154
2155 ret = walk_up_reloc_tree(reloc_root, path, &level);
2156 if (ret > 0)
2157 break;
2158
2159 BUG_ON(level == 0);
2160 /*
2161 * save the merging progress in the drop_progress.
2162 * this is OK since root refs == 1 in this case.
2163 */
2164 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2165 path->slots[level]);
2166 root_item->drop_level = level;
2167
2168 btrfs_end_transaction_throttle(trans, root);
2169 trans = NULL;
2170
2171 btrfs_btree_balance_dirty(root);
2172
2173 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2174 invalidate_extent_cache(root, &key, &next_key);
2175 }
2176
2177 /*
2178 * handle the case only one block in the fs tree need to be
2179 * relocated and the block is tree root.
2180 */
2181 leaf = btrfs_lock_root_node(root);
2182 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2183 btrfs_tree_unlock(leaf);
2184 free_extent_buffer(leaf);
2185 if (ret < 0)
2186 err = ret;
2187 out:
2188 btrfs_free_path(path);
2189
2190 if (err == 0) {
2191 memset(&root_item->drop_progress, 0,
2192 sizeof(root_item->drop_progress));
2193 root_item->drop_level = 0;
2194 btrfs_set_root_refs(root_item, 0);
2195 btrfs_update_reloc_root(trans, root);
2196 }
2197
2198 if (trans)
2199 btrfs_end_transaction_throttle(trans, root);
2200
2201 btrfs_btree_balance_dirty(root);
2202
2203 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2204 invalidate_extent_cache(root, &key, &next_key);
2205
2206 return err;
2207 }
2208
2209 static noinline_for_stack
2210 int prepare_to_merge(struct reloc_control *rc, int err)
2211 {
2212 struct btrfs_root *root = rc->extent_root;
2213 struct btrfs_root *reloc_root;
2214 struct btrfs_trans_handle *trans;
2215 LIST_HEAD(reloc_roots);
2216 u64 num_bytes = 0;
2217 int ret;
2218
2219 mutex_lock(&root->fs_info->reloc_mutex);
2220 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2221 rc->merging_rsv_size += rc->nodes_relocated * 2;
2222 mutex_unlock(&root->fs_info->reloc_mutex);
2223
2224 again:
2225 if (!err) {
2226 num_bytes = rc->merging_rsv_size;
2227 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2228 BTRFS_RESERVE_FLUSH_ALL);
2229 if (ret)
2230 err = ret;
2231 }
2232
2233 trans = btrfs_join_transaction(rc->extent_root);
2234 if (IS_ERR(trans)) {
2235 if (!err)
2236 btrfs_block_rsv_release(rc->extent_root,
2237 rc->block_rsv, num_bytes);
2238 return PTR_ERR(trans);
2239 }
2240
2241 if (!err) {
2242 if (num_bytes != rc->merging_rsv_size) {
2243 btrfs_end_transaction(trans, rc->extent_root);
2244 btrfs_block_rsv_release(rc->extent_root,
2245 rc->block_rsv, num_bytes);
2246 goto again;
2247 }
2248 }
2249
2250 rc->merge_reloc_tree = 1;
2251
2252 while (!list_empty(&rc->reloc_roots)) {
2253 reloc_root = list_entry(rc->reloc_roots.next,
2254 struct btrfs_root, root_list);
2255 list_del_init(&reloc_root->root_list);
2256
2257 root = read_fs_root(reloc_root->fs_info,
2258 reloc_root->root_key.offset);
2259 BUG_ON(IS_ERR(root));
2260 BUG_ON(root->reloc_root != reloc_root);
2261
2262 /*
2263 * set reference count to 1, so btrfs_recover_relocation
2264 * knows it should resumes merging
2265 */
2266 if (!err)
2267 btrfs_set_root_refs(&reloc_root->root_item, 1);
2268 btrfs_update_reloc_root(trans, root);
2269
2270 list_add(&reloc_root->root_list, &reloc_roots);
2271 }
2272
2273 list_splice(&reloc_roots, &rc->reloc_roots);
2274
2275 if (!err)
2276 btrfs_commit_transaction(trans, rc->extent_root);
2277 else
2278 btrfs_end_transaction(trans, rc->extent_root);
2279 return err;
2280 }
2281
2282 static noinline_for_stack
2283 void free_reloc_roots(struct list_head *list)
2284 {
2285 struct btrfs_root *reloc_root;
2286
2287 while (!list_empty(list)) {
2288 reloc_root = list_entry(list->next, struct btrfs_root,
2289 root_list);
2290 __update_reloc_root(reloc_root, 1);
2291 free_extent_buffer(reloc_root->node);
2292 free_extent_buffer(reloc_root->commit_root);
2293 kfree(reloc_root);
2294 }
2295 }
2296
2297 static noinline_for_stack
2298 int merge_reloc_roots(struct reloc_control *rc)
2299 {
2300 struct btrfs_trans_handle *trans;
2301 struct btrfs_root *root;
2302 struct btrfs_root *reloc_root;
2303 u64 last_snap;
2304 u64 otransid;
2305 u64 objectid;
2306 LIST_HEAD(reloc_roots);
2307 int found = 0;
2308 int ret = 0;
2309 again:
2310 root = rc->extent_root;
2311
2312 /*
2313 * this serializes us with btrfs_record_root_in_transaction,
2314 * we have to make sure nobody is in the middle of
2315 * adding their roots to the list while we are
2316 * doing this splice
2317 */
2318 mutex_lock(&root->fs_info->reloc_mutex);
2319 list_splice_init(&rc->reloc_roots, &reloc_roots);
2320 mutex_unlock(&root->fs_info->reloc_mutex);
2321
2322 while (!list_empty(&reloc_roots)) {
2323 found = 1;
2324 reloc_root = list_entry(reloc_roots.next,
2325 struct btrfs_root, root_list);
2326
2327 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2328 root = read_fs_root(reloc_root->fs_info,
2329 reloc_root->root_key.offset);
2330 BUG_ON(IS_ERR(root));
2331 BUG_ON(root->reloc_root != reloc_root);
2332
2333 ret = merge_reloc_root(rc, root);
2334 if (ret) {
2335 __update_reloc_root(reloc_root, 1);
2336 free_extent_buffer(reloc_root->node);
2337 free_extent_buffer(reloc_root->commit_root);
2338 kfree(reloc_root);
2339 goto out;
2340 }
2341 } else {
2342 list_del_init(&reloc_root->root_list);
2343 }
2344
2345 /*
2346 * we keep the old last snapshod transid in rtranid when we
2347 * created the relocation tree.
2348 */
2349 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2350 otransid = btrfs_root_otransid(&reloc_root->root_item);
2351 objectid = reloc_root->root_key.offset;
2352
2353 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2354 if (ret < 0) {
2355 if (list_empty(&reloc_root->root_list))
2356 list_add_tail(&reloc_root->root_list,
2357 &reloc_roots);
2358 goto out;
2359 } else if (!ret) {
2360 /*
2361 * recover the last snapshot tranid to avoid
2362 * the space balance break NOCOW.
2363 */
2364 root = read_fs_root(rc->extent_root->fs_info,
2365 objectid);
2366 if (IS_ERR(root))
2367 continue;
2368
2369 trans = btrfs_join_transaction(root);
2370 BUG_ON(IS_ERR(trans));
2371
2372 /* Check if the fs/file tree was snapshoted or not. */
2373 if (btrfs_root_last_snapshot(&root->root_item) ==
2374 otransid - 1)
2375 btrfs_set_root_last_snapshot(&root->root_item,
2376 last_snap);
2377
2378 btrfs_end_transaction(trans, root);
2379 }
2380 }
2381
2382 if (found) {
2383 found = 0;
2384 goto again;
2385 }
2386 out:
2387 if (ret) {
2388 btrfs_std_error(root->fs_info, ret);
2389 if (!list_empty(&reloc_roots))
2390 free_reloc_roots(&reloc_roots);
2391 }
2392
2393 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2394 return ret;
2395 }
2396
2397 static void free_block_list(struct rb_root *blocks)
2398 {
2399 struct tree_block *block;
2400 struct rb_node *rb_node;
2401 while ((rb_node = rb_first(blocks))) {
2402 block = rb_entry(rb_node, struct tree_block, rb_node);
2403 rb_erase(rb_node, blocks);
2404 kfree(block);
2405 }
2406 }
2407
2408 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2409 struct btrfs_root *reloc_root)
2410 {
2411 struct btrfs_root *root;
2412
2413 if (reloc_root->last_trans == trans->transid)
2414 return 0;
2415
2416 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2417 BUG_ON(IS_ERR(root));
2418 BUG_ON(root->reloc_root != reloc_root);
2419
2420 return btrfs_record_root_in_trans(trans, root);
2421 }
2422
2423 static noinline_for_stack
2424 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2425 struct reloc_control *rc,
2426 struct backref_node *node,
2427 struct backref_edge *edges[], int *nr)
2428 {
2429 struct backref_node *next;
2430 struct btrfs_root *root;
2431 int index = 0;
2432
2433 next = node;
2434 while (1) {
2435 cond_resched();
2436 next = walk_up_backref(next, edges, &index);
2437 root = next->root;
2438 BUG_ON(!root);
2439 BUG_ON(!root->ref_cows);
2440
2441 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2442 record_reloc_root_in_trans(trans, root);
2443 break;
2444 }
2445
2446 btrfs_record_root_in_trans(trans, root);
2447 root = root->reloc_root;
2448
2449 if (next->new_bytenr != root->node->start) {
2450 BUG_ON(next->new_bytenr);
2451 BUG_ON(!list_empty(&next->list));
2452 next->new_bytenr = root->node->start;
2453 next->root = root;
2454 list_add_tail(&next->list,
2455 &rc->backref_cache.changed);
2456 __mark_block_processed(rc, next);
2457 break;
2458 }
2459
2460 WARN_ON(1);
2461 root = NULL;
2462 next = walk_down_backref(edges, &index);
2463 if (!next || next->level <= node->level)
2464 break;
2465 }
2466 if (!root)
2467 return NULL;
2468
2469 *nr = index;
2470 next = node;
2471 /* setup backref node path for btrfs_reloc_cow_block */
2472 while (1) {
2473 rc->backref_cache.path[next->level] = next;
2474 if (--index < 0)
2475 break;
2476 next = edges[index]->node[UPPER];
2477 }
2478 return root;
2479 }
2480
2481 /*
2482 * select a tree root for relocation. return NULL if the block
2483 * is reference counted. we should use do_relocation() in this
2484 * case. return a tree root pointer if the block isn't reference
2485 * counted. return -ENOENT if the block is root of reloc tree.
2486 */
2487 static noinline_for_stack
2488 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2489 struct backref_node *node)
2490 {
2491 struct backref_node *next;
2492 struct btrfs_root *root;
2493 struct btrfs_root *fs_root = NULL;
2494 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2495 int index = 0;
2496
2497 next = node;
2498 while (1) {
2499 cond_resched();
2500 next = walk_up_backref(next, edges, &index);
2501 root = next->root;
2502 BUG_ON(!root);
2503
2504 /* no other choice for non-references counted tree */
2505 if (!root->ref_cows)
2506 return root;
2507
2508 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2509 fs_root = root;
2510
2511 if (next != node)
2512 return NULL;
2513
2514 next = walk_down_backref(edges, &index);
2515 if (!next || next->level <= node->level)
2516 break;
2517 }
2518
2519 if (!fs_root)
2520 return ERR_PTR(-ENOENT);
2521 return fs_root;
2522 }
2523
2524 static noinline_for_stack
2525 u64 calcu_metadata_size(struct reloc_control *rc,
2526 struct backref_node *node, int reserve)
2527 {
2528 struct backref_node *next = node;
2529 struct backref_edge *edge;
2530 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2531 u64 num_bytes = 0;
2532 int index = 0;
2533
2534 BUG_ON(reserve && node->processed);
2535
2536 while (next) {
2537 cond_resched();
2538 while (1) {
2539 if (next->processed && (reserve || next != node))
2540 break;
2541
2542 num_bytes += btrfs_level_size(rc->extent_root,
2543 next->level);
2544
2545 if (list_empty(&next->upper))
2546 break;
2547
2548 edge = list_entry(next->upper.next,
2549 struct backref_edge, list[LOWER]);
2550 edges[index++] = edge;
2551 next = edge->node[UPPER];
2552 }
2553 next = walk_down_backref(edges, &index);
2554 }
2555 return num_bytes;
2556 }
2557
2558 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2559 struct reloc_control *rc,
2560 struct backref_node *node)
2561 {
2562 struct btrfs_root *root = rc->extent_root;
2563 u64 num_bytes;
2564 int ret;
2565
2566 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2567
2568 trans->block_rsv = rc->block_rsv;
2569 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2570 BTRFS_RESERVE_FLUSH_ALL);
2571 if (ret) {
2572 if (ret == -EAGAIN)
2573 rc->commit_transaction = 1;
2574 return ret;
2575 }
2576
2577 return 0;
2578 }
2579
2580 static void release_metadata_space(struct reloc_control *rc,
2581 struct backref_node *node)
2582 {
2583 u64 num_bytes = calcu_metadata_size(rc, node, 0) * 2;
2584 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, num_bytes);
2585 }
2586
2587 /*
2588 * relocate a block tree, and then update pointers in upper level
2589 * blocks that reference the block to point to the new location.
2590 *
2591 * if called by link_to_upper, the block has already been relocated.
2592 * in that case this function just updates pointers.
2593 */
2594 static int do_relocation(struct btrfs_trans_handle *trans,
2595 struct reloc_control *rc,
2596 struct backref_node *node,
2597 struct btrfs_key *key,
2598 struct btrfs_path *path, int lowest)
2599 {
2600 struct backref_node *upper;
2601 struct backref_edge *edge;
2602 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2603 struct btrfs_root *root;
2604 struct extent_buffer *eb;
2605 u32 blocksize;
2606 u64 bytenr;
2607 u64 generation;
2608 int nr;
2609 int slot;
2610 int ret;
2611 int err = 0;
2612
2613 BUG_ON(lowest && node->eb);
2614
2615 path->lowest_level = node->level + 1;
2616 rc->backref_cache.path[node->level] = node;
2617 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2618 cond_resched();
2619
2620 upper = edge->node[UPPER];
2621 root = select_reloc_root(trans, rc, upper, edges, &nr);
2622 BUG_ON(!root);
2623
2624 if (upper->eb && !upper->locked) {
2625 if (!lowest) {
2626 ret = btrfs_bin_search(upper->eb, key,
2627 upper->level, &slot);
2628 BUG_ON(ret);
2629 bytenr = btrfs_node_blockptr(upper->eb, slot);
2630 if (node->eb->start == bytenr)
2631 goto next;
2632 }
2633 drop_node_buffer(upper);
2634 }
2635
2636 if (!upper->eb) {
2637 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2638 if (ret < 0) {
2639 err = ret;
2640 break;
2641 }
2642 BUG_ON(ret > 0);
2643
2644 if (!upper->eb) {
2645 upper->eb = path->nodes[upper->level];
2646 path->nodes[upper->level] = NULL;
2647 } else {
2648 BUG_ON(upper->eb != path->nodes[upper->level]);
2649 }
2650
2651 upper->locked = 1;
2652 path->locks[upper->level] = 0;
2653
2654 slot = path->slots[upper->level];
2655 btrfs_release_path(path);
2656 } else {
2657 ret = btrfs_bin_search(upper->eb, key, upper->level,
2658 &slot);
2659 BUG_ON(ret);
2660 }
2661
2662 bytenr = btrfs_node_blockptr(upper->eb, slot);
2663 if (lowest) {
2664 BUG_ON(bytenr != node->bytenr);
2665 } else {
2666 if (node->eb->start == bytenr)
2667 goto next;
2668 }
2669
2670 blocksize = btrfs_level_size(root, node->level);
2671 generation = btrfs_node_ptr_generation(upper->eb, slot);
2672 eb = read_tree_block(root, bytenr, blocksize, generation);
2673 if (!eb || !extent_buffer_uptodate(eb)) {
2674 free_extent_buffer(eb);
2675 err = -EIO;
2676 goto next;
2677 }
2678 btrfs_tree_lock(eb);
2679 btrfs_set_lock_blocking(eb);
2680
2681 if (!node->eb) {
2682 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2683 slot, &eb);
2684 btrfs_tree_unlock(eb);
2685 free_extent_buffer(eb);
2686 if (ret < 0) {
2687 err = ret;
2688 goto next;
2689 }
2690 BUG_ON(node->eb != eb);
2691 } else {
2692 btrfs_set_node_blockptr(upper->eb, slot,
2693 node->eb->start);
2694 btrfs_set_node_ptr_generation(upper->eb, slot,
2695 trans->transid);
2696 btrfs_mark_buffer_dirty(upper->eb);
2697
2698 ret = btrfs_inc_extent_ref(trans, root,
2699 node->eb->start, blocksize,
2700 upper->eb->start,
2701 btrfs_header_owner(upper->eb),
2702 node->level, 0, 1);
2703 BUG_ON(ret);
2704
2705 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2706 BUG_ON(ret);
2707 }
2708 next:
2709 if (!upper->pending)
2710 drop_node_buffer(upper);
2711 else
2712 unlock_node_buffer(upper);
2713 if (err)
2714 break;
2715 }
2716
2717 if (!err && node->pending) {
2718 drop_node_buffer(node);
2719 list_move_tail(&node->list, &rc->backref_cache.changed);
2720 node->pending = 0;
2721 }
2722
2723 path->lowest_level = 0;
2724 BUG_ON(err == -ENOSPC);
2725 return err;
2726 }
2727
2728 static int link_to_upper(struct btrfs_trans_handle *trans,
2729 struct reloc_control *rc,
2730 struct backref_node *node,
2731 struct btrfs_path *path)
2732 {
2733 struct btrfs_key key;
2734
2735 btrfs_node_key_to_cpu(node->eb, &key, 0);
2736 return do_relocation(trans, rc, node, &key, path, 0);
2737 }
2738
2739 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2740 struct reloc_control *rc,
2741 struct btrfs_path *path, int err)
2742 {
2743 LIST_HEAD(list);
2744 struct backref_cache *cache = &rc->backref_cache;
2745 struct backref_node *node;
2746 int level;
2747 int ret;
2748
2749 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2750 while (!list_empty(&cache->pending[level])) {
2751 node = list_entry(cache->pending[level].next,
2752 struct backref_node, list);
2753 list_move_tail(&node->list, &list);
2754 BUG_ON(!node->pending);
2755
2756 if (!err) {
2757 ret = link_to_upper(trans, rc, node, path);
2758 if (ret < 0)
2759 err = ret;
2760 }
2761 }
2762 list_splice_init(&list, &cache->pending[level]);
2763 }
2764 return err;
2765 }
2766
2767 static void mark_block_processed(struct reloc_control *rc,
2768 u64 bytenr, u32 blocksize)
2769 {
2770 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2771 EXTENT_DIRTY, GFP_NOFS);
2772 }
2773
2774 static void __mark_block_processed(struct reloc_control *rc,
2775 struct backref_node *node)
2776 {
2777 u32 blocksize;
2778 if (node->level == 0 ||
2779 in_block_group(node->bytenr, rc->block_group)) {
2780 blocksize = btrfs_level_size(rc->extent_root, node->level);
2781 mark_block_processed(rc, node->bytenr, blocksize);
2782 }
2783 node->processed = 1;
2784 }
2785
2786 /*
2787 * mark a block and all blocks directly/indirectly reference the block
2788 * as processed.
2789 */
2790 static void update_processed_blocks(struct reloc_control *rc,
2791 struct backref_node *node)
2792 {
2793 struct backref_node *next = node;
2794 struct backref_edge *edge;
2795 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2796 int index = 0;
2797
2798 while (next) {
2799 cond_resched();
2800 while (1) {
2801 if (next->processed)
2802 break;
2803
2804 __mark_block_processed(rc, next);
2805
2806 if (list_empty(&next->upper))
2807 break;
2808
2809 edge = list_entry(next->upper.next,
2810 struct backref_edge, list[LOWER]);
2811 edges[index++] = edge;
2812 next = edge->node[UPPER];
2813 }
2814 next = walk_down_backref(edges, &index);
2815 }
2816 }
2817
2818 static int tree_block_processed(u64 bytenr, u32 blocksize,
2819 struct reloc_control *rc)
2820 {
2821 if (test_range_bit(&rc->processed_blocks, bytenr,
2822 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2823 return 1;
2824 return 0;
2825 }
2826
2827 static int get_tree_block_key(struct reloc_control *rc,
2828 struct tree_block *block)
2829 {
2830 struct extent_buffer *eb;
2831
2832 BUG_ON(block->key_ready);
2833 eb = read_tree_block(rc->extent_root, block->bytenr,
2834 block->key.objectid, block->key.offset);
2835 if (!eb || !extent_buffer_uptodate(eb)) {
2836 free_extent_buffer(eb);
2837 return -EIO;
2838 }
2839 WARN_ON(btrfs_header_level(eb) != block->level);
2840 if (block->level == 0)
2841 btrfs_item_key_to_cpu(eb, &block->key, 0);
2842 else
2843 btrfs_node_key_to_cpu(eb, &block->key, 0);
2844 free_extent_buffer(eb);
2845 block->key_ready = 1;
2846 return 0;
2847 }
2848
2849 static int reada_tree_block(struct reloc_control *rc,
2850 struct tree_block *block)
2851 {
2852 BUG_ON(block->key_ready);
2853 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2854 readahead_tree_block(rc->extent_root, block->bytenr,
2855 block->key.objectid,
2856 rc->extent_root->leafsize);
2857 else
2858 readahead_tree_block(rc->extent_root, block->bytenr,
2859 block->key.objectid, block->key.offset);
2860 return 0;
2861 }
2862
2863 /*
2864 * helper function to relocate a tree block
2865 */
2866 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2867 struct reloc_control *rc,
2868 struct backref_node *node,
2869 struct btrfs_key *key,
2870 struct btrfs_path *path)
2871 {
2872 struct btrfs_root *root;
2873 int release = 0;
2874 int ret = 0;
2875
2876 if (!node)
2877 return 0;
2878
2879 BUG_ON(node->processed);
2880 root = select_one_root(trans, node);
2881 if (root == ERR_PTR(-ENOENT)) {
2882 update_processed_blocks(rc, node);
2883 goto out;
2884 }
2885
2886 if (!root || root->ref_cows) {
2887 ret = reserve_metadata_space(trans, rc, node);
2888 if (ret)
2889 goto out;
2890 release = 1;
2891 }
2892
2893 if (root) {
2894 if (root->ref_cows) {
2895 BUG_ON(node->new_bytenr);
2896 BUG_ON(!list_empty(&node->list));
2897 btrfs_record_root_in_trans(trans, root);
2898 root = root->reloc_root;
2899 node->new_bytenr = root->node->start;
2900 node->root = root;
2901 list_add_tail(&node->list, &rc->backref_cache.changed);
2902 } else {
2903 path->lowest_level = node->level;
2904 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2905 btrfs_release_path(path);
2906 if (ret > 0)
2907 ret = 0;
2908 }
2909 if (!ret)
2910 update_processed_blocks(rc, node);
2911 } else {
2912 ret = do_relocation(trans, rc, node, key, path, 1);
2913 }
2914 out:
2915 if (ret || node->level == 0 || node->cowonly) {
2916 if (release)
2917 release_metadata_space(rc, node);
2918 remove_backref_node(&rc->backref_cache, node);
2919 }
2920 return ret;
2921 }
2922
2923 /*
2924 * relocate a list of blocks
2925 */
2926 static noinline_for_stack
2927 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2928 struct reloc_control *rc, struct rb_root *blocks)
2929 {
2930 struct backref_node *node;
2931 struct btrfs_path *path;
2932 struct tree_block *block;
2933 struct rb_node *rb_node;
2934 int ret;
2935 int err = 0;
2936
2937 path = btrfs_alloc_path();
2938 if (!path) {
2939 err = -ENOMEM;
2940 goto out_free_blocks;
2941 }
2942
2943 rb_node = rb_first(blocks);
2944 while (rb_node) {
2945 block = rb_entry(rb_node, struct tree_block, rb_node);
2946 if (!block->key_ready)
2947 reada_tree_block(rc, block);
2948 rb_node = rb_next(rb_node);
2949 }
2950
2951 rb_node = rb_first(blocks);
2952 while (rb_node) {
2953 block = rb_entry(rb_node, struct tree_block, rb_node);
2954 if (!block->key_ready) {
2955 err = get_tree_block_key(rc, block);
2956 if (err)
2957 goto out_free_path;
2958 }
2959 rb_node = rb_next(rb_node);
2960 }
2961
2962 rb_node = rb_first(blocks);
2963 while (rb_node) {
2964 block = rb_entry(rb_node, struct tree_block, rb_node);
2965
2966 node = build_backref_tree(rc, &block->key,
2967 block->level, block->bytenr);
2968 if (IS_ERR(node)) {
2969 err = PTR_ERR(node);
2970 goto out;
2971 }
2972
2973 ret = relocate_tree_block(trans, rc, node, &block->key,
2974 path);
2975 if (ret < 0) {
2976 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2977 err = ret;
2978 goto out;
2979 }
2980 rb_node = rb_next(rb_node);
2981 }
2982 out:
2983 err = finish_pending_nodes(trans, rc, path, err);
2984
2985 out_free_path:
2986 btrfs_free_path(path);
2987 out_free_blocks:
2988 free_block_list(blocks);
2989 return err;
2990 }
2991
2992 static noinline_for_stack
2993 int prealloc_file_extent_cluster(struct inode *inode,
2994 struct file_extent_cluster *cluster)
2995 {
2996 u64 alloc_hint = 0;
2997 u64 start;
2998 u64 end;
2999 u64 offset = BTRFS_I(inode)->index_cnt;
3000 u64 num_bytes;
3001 int nr = 0;
3002 int ret = 0;
3003
3004 BUG_ON(cluster->start != cluster->boundary[0]);
3005 mutex_lock(&inode->i_mutex);
3006
3007 ret = btrfs_check_data_free_space(inode, cluster->end +
3008 1 - cluster->start);
3009 if (ret)
3010 goto out;
3011
3012 while (nr < cluster->nr) {
3013 start = cluster->boundary[nr] - offset;
3014 if (nr + 1 < cluster->nr)
3015 end = cluster->boundary[nr + 1] - 1 - offset;
3016 else
3017 end = cluster->end - offset;
3018
3019 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3020 num_bytes = end + 1 - start;
3021 ret = btrfs_prealloc_file_range(inode, 0, start,
3022 num_bytes, num_bytes,
3023 end + 1, &alloc_hint);
3024 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3025 if (ret)
3026 break;
3027 nr++;
3028 }
3029 btrfs_free_reserved_data_space(inode, cluster->end +
3030 1 - cluster->start);
3031 out:
3032 mutex_unlock(&inode->i_mutex);
3033 return ret;
3034 }
3035
3036 static noinline_for_stack
3037 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3038 u64 block_start)
3039 {
3040 struct btrfs_root *root = BTRFS_I(inode)->root;
3041 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3042 struct extent_map *em;
3043 int ret = 0;
3044
3045 em = alloc_extent_map();
3046 if (!em)
3047 return -ENOMEM;
3048
3049 em->start = start;
3050 em->len = end + 1 - start;
3051 em->block_len = em->len;
3052 em->block_start = block_start;
3053 em->bdev = root->fs_info->fs_devices->latest_bdev;
3054 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3055
3056 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3057 while (1) {
3058 write_lock(&em_tree->lock);
3059 ret = add_extent_mapping(em_tree, em, 0);
3060 write_unlock(&em_tree->lock);
3061 if (ret != -EEXIST) {
3062 free_extent_map(em);
3063 break;
3064 }
3065 btrfs_drop_extent_cache(inode, start, end, 0);
3066 }
3067 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3068 return ret;
3069 }
3070
3071 static int relocate_file_extent_cluster(struct inode *inode,
3072 struct file_extent_cluster *cluster)
3073 {
3074 u64 page_start;
3075 u64 page_end;
3076 u64 offset = BTRFS_I(inode)->index_cnt;
3077 unsigned long index;
3078 unsigned long last_index;
3079 struct page *page;
3080 struct file_ra_state *ra;
3081 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3082 int nr = 0;
3083 int ret = 0;
3084
3085 if (!cluster->nr)
3086 return 0;
3087
3088 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3089 if (!ra)
3090 return -ENOMEM;
3091
3092 ret = prealloc_file_extent_cluster(inode, cluster);
3093 if (ret)
3094 goto out;
3095
3096 file_ra_state_init(ra, inode->i_mapping);
3097
3098 ret = setup_extent_mapping(inode, cluster->start - offset,
3099 cluster->end - offset, cluster->start);
3100 if (ret)
3101 goto out;
3102
3103 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3104 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3105 while (index <= last_index) {
3106 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3107 if (ret)
3108 goto out;
3109
3110 page = find_lock_page(inode->i_mapping, index);
3111 if (!page) {
3112 page_cache_sync_readahead(inode->i_mapping,
3113 ra, NULL, index,
3114 last_index + 1 - index);
3115 page = find_or_create_page(inode->i_mapping, index,
3116 mask);
3117 if (!page) {
3118 btrfs_delalloc_release_metadata(inode,
3119 PAGE_CACHE_SIZE);
3120 ret = -ENOMEM;
3121 goto out;
3122 }
3123 }
3124
3125 if (PageReadahead(page)) {
3126 page_cache_async_readahead(inode->i_mapping,
3127 ra, NULL, page, index,
3128 last_index + 1 - index);
3129 }
3130
3131 if (!PageUptodate(page)) {
3132 btrfs_readpage(NULL, page);
3133 lock_page(page);
3134 if (!PageUptodate(page)) {
3135 unlock_page(page);
3136 page_cache_release(page);
3137 btrfs_delalloc_release_metadata(inode,
3138 PAGE_CACHE_SIZE);
3139 ret = -EIO;
3140 goto out;
3141 }
3142 }
3143
3144 page_start = page_offset(page);
3145 page_end = page_start + PAGE_CACHE_SIZE - 1;
3146
3147 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3148
3149 set_page_extent_mapped(page);
3150
3151 if (nr < cluster->nr &&
3152 page_start + offset == cluster->boundary[nr]) {
3153 set_extent_bits(&BTRFS_I(inode)->io_tree,
3154 page_start, page_end,
3155 EXTENT_BOUNDARY, GFP_NOFS);
3156 nr++;
3157 }
3158
3159 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3160 set_page_dirty(page);
3161
3162 unlock_extent(&BTRFS_I(inode)->io_tree,
3163 page_start, page_end);
3164 unlock_page(page);
3165 page_cache_release(page);
3166
3167 index++;
3168 balance_dirty_pages_ratelimited(inode->i_mapping);
3169 btrfs_throttle(BTRFS_I(inode)->root);
3170 }
3171 WARN_ON(nr != cluster->nr);
3172 out:
3173 kfree(ra);
3174 return ret;
3175 }
3176
3177 static noinline_for_stack
3178 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3179 struct file_extent_cluster *cluster)
3180 {
3181 int ret;
3182
3183 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3184 ret = relocate_file_extent_cluster(inode, cluster);
3185 if (ret)
3186 return ret;
3187 cluster->nr = 0;
3188 }
3189
3190 if (!cluster->nr)
3191 cluster->start = extent_key->objectid;
3192 else
3193 BUG_ON(cluster->nr >= MAX_EXTENTS);
3194 cluster->end = extent_key->objectid + extent_key->offset - 1;
3195 cluster->boundary[cluster->nr] = extent_key->objectid;
3196 cluster->nr++;
3197
3198 if (cluster->nr >= MAX_EXTENTS) {
3199 ret = relocate_file_extent_cluster(inode, cluster);
3200 if (ret)
3201 return ret;
3202 cluster->nr = 0;
3203 }
3204 return 0;
3205 }
3206
3207 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3208 static int get_ref_objectid_v0(struct reloc_control *rc,
3209 struct btrfs_path *path,
3210 struct btrfs_key *extent_key,
3211 u64 *ref_objectid, int *path_change)
3212 {
3213 struct btrfs_key key;
3214 struct extent_buffer *leaf;
3215 struct btrfs_extent_ref_v0 *ref0;
3216 int ret;
3217 int slot;
3218
3219 leaf = path->nodes[0];
3220 slot = path->slots[0];
3221 while (1) {
3222 if (slot >= btrfs_header_nritems(leaf)) {
3223 ret = btrfs_next_leaf(rc->extent_root, path);
3224 if (ret < 0)
3225 return ret;
3226 BUG_ON(ret > 0);
3227 leaf = path->nodes[0];
3228 slot = path->slots[0];
3229 if (path_change)
3230 *path_change = 1;
3231 }
3232 btrfs_item_key_to_cpu(leaf, &key, slot);
3233 if (key.objectid != extent_key->objectid)
3234 return -ENOENT;
3235
3236 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3237 slot++;
3238 continue;
3239 }
3240 ref0 = btrfs_item_ptr(leaf, slot,
3241 struct btrfs_extent_ref_v0);
3242 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3243 break;
3244 }
3245 return 0;
3246 }
3247 #endif
3248
3249 /*
3250 * helper to add a tree block to the list.
3251 * the major work is getting the generation and level of the block
3252 */
3253 static int add_tree_block(struct reloc_control *rc,
3254 struct btrfs_key *extent_key,
3255 struct btrfs_path *path,
3256 struct rb_root *blocks)
3257 {
3258 struct extent_buffer *eb;
3259 struct btrfs_extent_item *ei;
3260 struct btrfs_tree_block_info *bi;
3261 struct tree_block *block;
3262 struct rb_node *rb_node;
3263 u32 item_size;
3264 int level = -1;
3265 u64 generation;
3266
3267 eb = path->nodes[0];
3268 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3269
3270 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3271 item_size >= sizeof(*ei) + sizeof(*bi)) {
3272 ei = btrfs_item_ptr(eb, path->slots[0],
3273 struct btrfs_extent_item);
3274 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3275 bi = (struct btrfs_tree_block_info *)(ei + 1);
3276 level = btrfs_tree_block_level(eb, bi);
3277 } else {
3278 level = (int)extent_key->offset;
3279 }
3280 generation = btrfs_extent_generation(eb, ei);
3281 } else {
3282 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3283 u64 ref_owner;
3284 int ret;
3285
3286 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3287 ret = get_ref_objectid_v0(rc, path, extent_key,
3288 &ref_owner, NULL);
3289 if (ret < 0)
3290 return ret;
3291 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3292 level = (int)ref_owner;
3293 /* FIXME: get real generation */
3294 generation = 0;
3295 #else
3296 BUG();
3297 #endif
3298 }
3299
3300 btrfs_release_path(path);
3301
3302 BUG_ON(level == -1);
3303
3304 block = kmalloc(sizeof(*block), GFP_NOFS);
3305 if (!block)
3306 return -ENOMEM;
3307
3308 block->bytenr = extent_key->objectid;
3309 block->key.objectid = rc->extent_root->leafsize;
3310 block->key.offset = generation;
3311 block->level = level;
3312 block->key_ready = 0;
3313
3314 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3315 if (rb_node)
3316 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3317
3318 return 0;
3319 }
3320
3321 /*
3322 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3323 */
3324 static int __add_tree_block(struct reloc_control *rc,
3325 u64 bytenr, u32 blocksize,
3326 struct rb_root *blocks)
3327 {
3328 struct btrfs_path *path;
3329 struct btrfs_key key;
3330 int ret;
3331 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3332 SKINNY_METADATA);
3333
3334 if (tree_block_processed(bytenr, blocksize, rc))
3335 return 0;
3336
3337 if (tree_search(blocks, bytenr))
3338 return 0;
3339
3340 path = btrfs_alloc_path();
3341 if (!path)
3342 return -ENOMEM;
3343 again:
3344 key.objectid = bytenr;
3345 if (skinny) {
3346 key.type = BTRFS_METADATA_ITEM_KEY;
3347 key.offset = (u64)-1;
3348 } else {
3349 key.type = BTRFS_EXTENT_ITEM_KEY;
3350 key.offset = blocksize;
3351 }
3352
3353 path->search_commit_root = 1;
3354 path->skip_locking = 1;
3355 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3356 if (ret < 0)
3357 goto out;
3358
3359 if (ret > 0 && skinny) {
3360 if (path->slots[0]) {
3361 path->slots[0]--;
3362 btrfs_item_key_to_cpu(path->nodes[0], &key,
3363 path->slots[0]);
3364 if (key.objectid == bytenr &&
3365 (key.type == BTRFS_METADATA_ITEM_KEY ||
3366 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3367 key.offset == blocksize)))
3368 ret = 0;
3369 }
3370
3371 if (ret) {
3372 skinny = false;
3373 btrfs_release_path(path);
3374 goto again;
3375 }
3376 }
3377 BUG_ON(ret);
3378
3379 ret = add_tree_block(rc, &key, path, blocks);
3380 out:
3381 btrfs_free_path(path);
3382 return ret;
3383 }
3384
3385 /*
3386 * helper to check if the block use full backrefs for pointers in it
3387 */
3388 static int block_use_full_backref(struct reloc_control *rc,
3389 struct extent_buffer *eb)
3390 {
3391 u64 flags;
3392 int ret;
3393
3394 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3395 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3396 return 1;
3397
3398 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3399 eb->start, btrfs_header_level(eb), 1,
3400 NULL, &flags);
3401 BUG_ON(ret);
3402
3403 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3404 ret = 1;
3405 else
3406 ret = 0;
3407 return ret;
3408 }
3409
3410 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3411 struct inode *inode, u64 ino)
3412 {
3413 struct btrfs_key key;
3414 struct btrfs_root *root = fs_info->tree_root;
3415 struct btrfs_trans_handle *trans;
3416 int ret = 0;
3417
3418 if (inode)
3419 goto truncate;
3420
3421 key.objectid = ino;
3422 key.type = BTRFS_INODE_ITEM_KEY;
3423 key.offset = 0;
3424
3425 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3426 if (IS_ERR(inode) || is_bad_inode(inode)) {
3427 if (!IS_ERR(inode))
3428 iput(inode);
3429 return -ENOENT;
3430 }
3431
3432 truncate:
3433 ret = btrfs_check_trunc_cache_free_space(root,
3434 &fs_info->global_block_rsv);
3435 if (ret)
3436 goto out;
3437
3438 trans = btrfs_join_transaction(root);
3439 if (IS_ERR(trans)) {
3440 ret = PTR_ERR(trans);
3441 goto out;
3442 }
3443
3444 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3445
3446 btrfs_end_transaction(trans, root);
3447 btrfs_btree_balance_dirty(root);
3448 out:
3449 iput(inode);
3450 return ret;
3451 }
3452
3453 /*
3454 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3455 * this function scans fs tree to find blocks reference the data extent
3456 */
3457 static int find_data_references(struct reloc_control *rc,
3458 struct btrfs_key *extent_key,
3459 struct extent_buffer *leaf,
3460 struct btrfs_extent_data_ref *ref,
3461 struct rb_root *blocks)
3462 {
3463 struct btrfs_path *path;
3464 struct tree_block *block;
3465 struct btrfs_root *root;
3466 struct btrfs_file_extent_item *fi;
3467 struct rb_node *rb_node;
3468 struct btrfs_key key;
3469 u64 ref_root;
3470 u64 ref_objectid;
3471 u64 ref_offset;
3472 u32 ref_count;
3473 u32 nritems;
3474 int err = 0;
3475 int added = 0;
3476 int counted;
3477 int ret;
3478
3479 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3480 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3481 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3482 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3483
3484 /*
3485 * This is an extent belonging to the free space cache, lets just delete
3486 * it and redo the search.
3487 */
3488 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3489 ret = delete_block_group_cache(rc->extent_root->fs_info,
3490 NULL, ref_objectid);
3491 if (ret != -ENOENT)
3492 return ret;
3493 ret = 0;
3494 }
3495
3496 path = btrfs_alloc_path();
3497 if (!path)
3498 return -ENOMEM;
3499 path->reada = 1;
3500
3501 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3502 if (IS_ERR(root)) {
3503 err = PTR_ERR(root);
3504 goto out;
3505 }
3506
3507 key.objectid = ref_objectid;
3508 key.type = BTRFS_EXTENT_DATA_KEY;
3509 if (ref_offset > ((u64)-1 << 32))
3510 key.offset = 0;
3511 else
3512 key.offset = ref_offset;
3513
3514 path->search_commit_root = 1;
3515 path->skip_locking = 1;
3516 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3517 if (ret < 0) {
3518 err = ret;
3519 goto out;
3520 }
3521
3522 leaf = path->nodes[0];
3523 nritems = btrfs_header_nritems(leaf);
3524 /*
3525 * the references in tree blocks that use full backrefs
3526 * are not counted in
3527 */
3528 if (block_use_full_backref(rc, leaf))
3529 counted = 0;
3530 else
3531 counted = 1;
3532 rb_node = tree_search(blocks, leaf->start);
3533 if (rb_node) {
3534 if (counted)
3535 added = 1;
3536 else
3537 path->slots[0] = nritems;
3538 }
3539
3540 while (ref_count > 0) {
3541 while (path->slots[0] >= nritems) {
3542 ret = btrfs_next_leaf(root, path);
3543 if (ret < 0) {
3544 err = ret;
3545 goto out;
3546 }
3547 if (WARN_ON(ret > 0))
3548 goto out;
3549
3550 leaf = path->nodes[0];
3551 nritems = btrfs_header_nritems(leaf);
3552 added = 0;
3553
3554 if (block_use_full_backref(rc, leaf))
3555 counted = 0;
3556 else
3557 counted = 1;
3558 rb_node = tree_search(blocks, leaf->start);
3559 if (rb_node) {
3560 if (counted)
3561 added = 1;
3562 else
3563 path->slots[0] = nritems;
3564 }
3565 }
3566
3567 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3568 if (WARN_ON(key.objectid != ref_objectid ||
3569 key.type != BTRFS_EXTENT_DATA_KEY))
3570 break;
3571
3572 fi = btrfs_item_ptr(leaf, path->slots[0],
3573 struct btrfs_file_extent_item);
3574
3575 if (btrfs_file_extent_type(leaf, fi) ==
3576 BTRFS_FILE_EXTENT_INLINE)
3577 goto next;
3578
3579 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3580 extent_key->objectid)
3581 goto next;
3582
3583 key.offset -= btrfs_file_extent_offset(leaf, fi);
3584 if (key.offset != ref_offset)
3585 goto next;
3586
3587 if (counted)
3588 ref_count--;
3589 if (added)
3590 goto next;
3591
3592 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3593 block = kmalloc(sizeof(*block), GFP_NOFS);
3594 if (!block) {
3595 err = -ENOMEM;
3596 break;
3597 }
3598 block->bytenr = leaf->start;
3599 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3600 block->level = 0;
3601 block->key_ready = 1;
3602 rb_node = tree_insert(blocks, block->bytenr,
3603 &block->rb_node);
3604 if (rb_node)
3605 backref_tree_panic(rb_node, -EEXIST,
3606 block->bytenr);
3607 }
3608 if (counted)
3609 added = 1;
3610 else
3611 path->slots[0] = nritems;
3612 next:
3613 path->slots[0]++;
3614
3615 }
3616 out:
3617 btrfs_free_path(path);
3618 return err;
3619 }
3620
3621 /*
3622 * helper to find all tree blocks that reference a given data extent
3623 */
3624 static noinline_for_stack
3625 int add_data_references(struct reloc_control *rc,
3626 struct btrfs_key *extent_key,
3627 struct btrfs_path *path,
3628 struct rb_root *blocks)
3629 {
3630 struct btrfs_key key;
3631 struct extent_buffer *eb;
3632 struct btrfs_extent_data_ref *dref;
3633 struct btrfs_extent_inline_ref *iref;
3634 unsigned long ptr;
3635 unsigned long end;
3636 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3637 int ret = 0;
3638 int err = 0;
3639
3640 eb = path->nodes[0];
3641 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3642 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3643 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3644 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3645 ptr = end;
3646 else
3647 #endif
3648 ptr += sizeof(struct btrfs_extent_item);
3649
3650 while (ptr < end) {
3651 iref = (struct btrfs_extent_inline_ref *)ptr;
3652 key.type = btrfs_extent_inline_ref_type(eb, iref);
3653 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3654 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3655 ret = __add_tree_block(rc, key.offset, blocksize,
3656 blocks);
3657 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3658 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3659 ret = find_data_references(rc, extent_key,
3660 eb, dref, blocks);
3661 } else {
3662 BUG();
3663 }
3664 if (ret) {
3665 err = ret;
3666 goto out;
3667 }
3668 ptr += btrfs_extent_inline_ref_size(key.type);
3669 }
3670 WARN_ON(ptr > end);
3671
3672 while (1) {
3673 cond_resched();
3674 eb = path->nodes[0];
3675 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3676 ret = btrfs_next_leaf(rc->extent_root, path);
3677 if (ret < 0) {
3678 err = ret;
3679 break;
3680 }
3681 if (ret > 0)
3682 break;
3683 eb = path->nodes[0];
3684 }
3685
3686 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3687 if (key.objectid != extent_key->objectid)
3688 break;
3689
3690 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3691 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3692 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3693 #else
3694 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3695 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3696 #endif
3697 ret = __add_tree_block(rc, key.offset, blocksize,
3698 blocks);
3699 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3700 dref = btrfs_item_ptr(eb, path->slots[0],
3701 struct btrfs_extent_data_ref);
3702 ret = find_data_references(rc, extent_key,
3703 eb, dref, blocks);
3704 } else {
3705 ret = 0;
3706 }
3707 if (ret) {
3708 err = ret;
3709 break;
3710 }
3711 path->slots[0]++;
3712 }
3713 out:
3714 btrfs_release_path(path);
3715 if (err)
3716 free_block_list(blocks);
3717 return err;
3718 }
3719
3720 /*
3721 * helper to find next unprocessed extent
3722 */
3723 static noinline_for_stack
3724 int find_next_extent(struct btrfs_trans_handle *trans,
3725 struct reloc_control *rc, struct btrfs_path *path,
3726 struct btrfs_key *extent_key)
3727 {
3728 struct btrfs_key key;
3729 struct extent_buffer *leaf;
3730 u64 start, end, last;
3731 int ret;
3732
3733 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3734 while (1) {
3735 cond_resched();
3736 if (rc->search_start >= last) {
3737 ret = 1;
3738 break;
3739 }
3740
3741 key.objectid = rc->search_start;
3742 key.type = BTRFS_EXTENT_ITEM_KEY;
3743 key.offset = 0;
3744
3745 path->search_commit_root = 1;
3746 path->skip_locking = 1;
3747 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3748 0, 0);
3749 if (ret < 0)
3750 break;
3751 next:
3752 leaf = path->nodes[0];
3753 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3754 ret = btrfs_next_leaf(rc->extent_root, path);
3755 if (ret != 0)
3756 break;
3757 leaf = path->nodes[0];
3758 }
3759
3760 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3761 if (key.objectid >= last) {
3762 ret = 1;
3763 break;
3764 }
3765
3766 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3767 key.type != BTRFS_METADATA_ITEM_KEY) {
3768 path->slots[0]++;
3769 goto next;
3770 }
3771
3772 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3773 key.objectid + key.offset <= rc->search_start) {
3774 path->slots[0]++;
3775 goto next;
3776 }
3777
3778 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3779 key.objectid + rc->extent_root->leafsize <=
3780 rc->search_start) {
3781 path->slots[0]++;
3782 goto next;
3783 }
3784
3785 ret = find_first_extent_bit(&rc->processed_blocks,
3786 key.objectid, &start, &end,
3787 EXTENT_DIRTY, NULL);
3788
3789 if (ret == 0 && start <= key.objectid) {
3790 btrfs_release_path(path);
3791 rc->search_start = end + 1;
3792 } else {
3793 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3794 rc->search_start = key.objectid + key.offset;
3795 else
3796 rc->search_start = key.objectid +
3797 rc->extent_root->leafsize;
3798 memcpy(extent_key, &key, sizeof(key));
3799 return 0;
3800 }
3801 }
3802 btrfs_release_path(path);
3803 return ret;
3804 }
3805
3806 static void set_reloc_control(struct reloc_control *rc)
3807 {
3808 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3809
3810 mutex_lock(&fs_info->reloc_mutex);
3811 fs_info->reloc_ctl = rc;
3812 mutex_unlock(&fs_info->reloc_mutex);
3813 }
3814
3815 static void unset_reloc_control(struct reloc_control *rc)
3816 {
3817 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3818
3819 mutex_lock(&fs_info->reloc_mutex);
3820 fs_info->reloc_ctl = NULL;
3821 mutex_unlock(&fs_info->reloc_mutex);
3822 }
3823
3824 static int check_extent_flags(u64 flags)
3825 {
3826 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3827 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3828 return 1;
3829 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3830 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3831 return 1;
3832 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3833 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3834 return 1;
3835 return 0;
3836 }
3837
3838 static noinline_for_stack
3839 int prepare_to_relocate(struct reloc_control *rc)
3840 {
3841 struct btrfs_trans_handle *trans;
3842 int ret;
3843
3844 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3845 BTRFS_BLOCK_RSV_TEMP);
3846 if (!rc->block_rsv)
3847 return -ENOMEM;
3848
3849 /*
3850 * reserve some space for creating reloc trees.
3851 * btrfs_init_reloc_root will use them when there
3852 * is no reservation in transaction handle.
3853 */
3854 ret = btrfs_block_rsv_add(rc->extent_root, rc->block_rsv,
3855 rc->extent_root->nodesize * 256,
3856 BTRFS_RESERVE_FLUSH_ALL);
3857 if (ret)
3858 return ret;
3859
3860 memset(&rc->cluster, 0, sizeof(rc->cluster));
3861 rc->search_start = rc->block_group->key.objectid;
3862 rc->extents_found = 0;
3863 rc->nodes_relocated = 0;
3864 rc->merging_rsv_size = 0;
3865
3866 rc->create_reloc_tree = 1;
3867 set_reloc_control(rc);
3868
3869 trans = btrfs_join_transaction(rc->extent_root);
3870 if (IS_ERR(trans)) {
3871 unset_reloc_control(rc);
3872 /*
3873 * extent tree is not a ref_cow tree and has no reloc_root to
3874 * cleanup. And callers are responsible to free the above
3875 * block rsv.
3876 */
3877 return PTR_ERR(trans);
3878 }
3879 btrfs_commit_transaction(trans, rc->extent_root);
3880 return 0;
3881 }
3882
3883 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3884 {
3885 struct rb_root blocks = RB_ROOT;
3886 struct btrfs_key key;
3887 struct btrfs_trans_handle *trans = NULL;
3888 struct btrfs_path *path;
3889 struct btrfs_extent_item *ei;
3890 u64 flags;
3891 u32 item_size;
3892 int ret;
3893 int err = 0;
3894 int progress = 0;
3895
3896 path = btrfs_alloc_path();
3897 if (!path)
3898 return -ENOMEM;
3899 path->reada = 1;
3900
3901 ret = prepare_to_relocate(rc);
3902 if (ret) {
3903 err = ret;
3904 goto out_free;
3905 }
3906
3907 while (1) {
3908 progress++;
3909 trans = btrfs_start_transaction(rc->extent_root, 0);
3910 if (IS_ERR(trans)) {
3911 err = PTR_ERR(trans);
3912 trans = NULL;
3913 break;
3914 }
3915 restart:
3916 if (update_backref_cache(trans, &rc->backref_cache)) {
3917 btrfs_end_transaction(trans, rc->extent_root);
3918 continue;
3919 }
3920
3921 ret = find_next_extent(trans, rc, path, &key);
3922 if (ret < 0)
3923 err = ret;
3924 if (ret != 0)
3925 break;
3926
3927 rc->extents_found++;
3928
3929 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3930 struct btrfs_extent_item);
3931 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3932 if (item_size >= sizeof(*ei)) {
3933 flags = btrfs_extent_flags(path->nodes[0], ei);
3934 ret = check_extent_flags(flags);
3935 BUG_ON(ret);
3936
3937 } else {
3938 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3939 u64 ref_owner;
3940 int path_change = 0;
3941
3942 BUG_ON(item_size !=
3943 sizeof(struct btrfs_extent_item_v0));
3944 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3945 &path_change);
3946 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3947 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3948 else
3949 flags = BTRFS_EXTENT_FLAG_DATA;
3950
3951 if (path_change) {
3952 btrfs_release_path(path);
3953
3954 path->search_commit_root = 1;
3955 path->skip_locking = 1;
3956 ret = btrfs_search_slot(NULL, rc->extent_root,
3957 &key, path, 0, 0);
3958 if (ret < 0) {
3959 err = ret;
3960 break;
3961 }
3962 BUG_ON(ret > 0);
3963 }
3964 #else
3965 BUG();
3966 #endif
3967 }
3968
3969 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3970 ret = add_tree_block(rc, &key, path, &blocks);
3971 } else if (rc->stage == UPDATE_DATA_PTRS &&
3972 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3973 ret = add_data_references(rc, &key, path, &blocks);
3974 } else {
3975 btrfs_release_path(path);
3976 ret = 0;
3977 }
3978 if (ret < 0) {
3979 err = ret;
3980 break;
3981 }
3982
3983 if (!RB_EMPTY_ROOT(&blocks)) {
3984 ret = relocate_tree_blocks(trans, rc, &blocks);
3985 if (ret < 0) {
3986 if (ret != -EAGAIN) {
3987 err = ret;
3988 break;
3989 }
3990 rc->extents_found--;
3991 rc->search_start = key.objectid;
3992 }
3993 }
3994
3995 if (rc->commit_transaction) {
3996 rc->commit_transaction = 0;
3997 ret = btrfs_commit_transaction(trans, rc->extent_root);
3998 BUG_ON(ret);
3999 } else {
4000 btrfs_end_transaction_throttle(trans, rc->extent_root);
4001 btrfs_btree_balance_dirty(rc->extent_root);
4002 }
4003 trans = NULL;
4004
4005 if (rc->stage == MOVE_DATA_EXTENTS &&
4006 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4007 rc->found_file_extent = 1;
4008 ret = relocate_data_extent(rc->data_inode,
4009 &key, &rc->cluster);
4010 if (ret < 0) {
4011 err = ret;
4012 break;
4013 }
4014 }
4015 }
4016 if (trans && progress && err == -ENOSPC) {
4017 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4018 rc->block_group->flags);
4019 if (ret == 0) {
4020 err = 0;
4021 progress = 0;
4022 goto restart;
4023 }
4024 }
4025
4026 btrfs_release_path(path);
4027 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4028 GFP_NOFS);
4029
4030 if (trans) {
4031 btrfs_end_transaction_throttle(trans, rc->extent_root);
4032 btrfs_btree_balance_dirty(rc->extent_root);
4033 }
4034
4035 if (!err) {
4036 ret = relocate_file_extent_cluster(rc->data_inode,
4037 &rc->cluster);
4038 if (ret < 0)
4039 err = ret;
4040 }
4041
4042 rc->create_reloc_tree = 0;
4043 set_reloc_control(rc);
4044
4045 backref_cache_cleanup(&rc->backref_cache);
4046 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4047
4048 err = prepare_to_merge(rc, err);
4049
4050 merge_reloc_roots(rc);
4051
4052 rc->merge_reloc_tree = 0;
4053 unset_reloc_control(rc);
4054 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4055
4056 /* get rid of pinned extents */
4057 trans = btrfs_join_transaction(rc->extent_root);
4058 if (IS_ERR(trans))
4059 err = PTR_ERR(trans);
4060 else
4061 btrfs_commit_transaction(trans, rc->extent_root);
4062 out_free:
4063 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4064 btrfs_free_path(path);
4065 return err;
4066 }
4067
4068 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4069 struct btrfs_root *root, u64 objectid)
4070 {
4071 struct btrfs_path *path;
4072 struct btrfs_inode_item *item;
4073 struct extent_buffer *leaf;
4074 int ret;
4075
4076 path = btrfs_alloc_path();
4077 if (!path)
4078 return -ENOMEM;
4079
4080 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4081 if (ret)
4082 goto out;
4083
4084 leaf = path->nodes[0];
4085 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4086 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4087 btrfs_set_inode_generation(leaf, item, 1);
4088 btrfs_set_inode_size(leaf, item, 0);
4089 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4090 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4091 BTRFS_INODE_PREALLOC);
4092 btrfs_mark_buffer_dirty(leaf);
4093 btrfs_release_path(path);
4094 out:
4095 btrfs_free_path(path);
4096 return ret;
4097 }
4098
4099 /*
4100 * helper to create inode for data relocation.
4101 * the inode is in data relocation tree and its link count is 0
4102 */
4103 static noinline_for_stack
4104 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4105 struct btrfs_block_group_cache *group)
4106 {
4107 struct inode *inode = NULL;
4108 struct btrfs_trans_handle *trans;
4109 struct btrfs_root *root;
4110 struct btrfs_key key;
4111 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4112 int err = 0;
4113
4114 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4115 if (IS_ERR(root))
4116 return ERR_CAST(root);
4117
4118 trans = btrfs_start_transaction(root, 6);
4119 if (IS_ERR(trans))
4120 return ERR_CAST(trans);
4121
4122 err = btrfs_find_free_objectid(root, &objectid);
4123 if (err)
4124 goto out;
4125
4126 err = __insert_orphan_inode(trans, root, objectid);
4127 BUG_ON(err);
4128
4129 key.objectid = objectid;
4130 key.type = BTRFS_INODE_ITEM_KEY;
4131 key.offset = 0;
4132 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4133 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4134 BTRFS_I(inode)->index_cnt = group->key.objectid;
4135
4136 err = btrfs_orphan_add(trans, inode);
4137 out:
4138 btrfs_end_transaction(trans, root);
4139 btrfs_btree_balance_dirty(root);
4140 if (err) {
4141 if (inode)
4142 iput(inode);
4143 inode = ERR_PTR(err);
4144 }
4145 return inode;
4146 }
4147
4148 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4149 {
4150 struct reloc_control *rc;
4151
4152 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4153 if (!rc)
4154 return NULL;
4155
4156 INIT_LIST_HEAD(&rc->reloc_roots);
4157 backref_cache_init(&rc->backref_cache);
4158 mapping_tree_init(&rc->reloc_root_tree);
4159 extent_io_tree_init(&rc->processed_blocks,
4160 fs_info->btree_inode->i_mapping);
4161 return rc;
4162 }
4163
4164 /*
4165 * function to relocate all extents in a block group.
4166 */
4167 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4168 {
4169 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4170 struct reloc_control *rc;
4171 struct inode *inode;
4172 struct btrfs_path *path;
4173 int ret;
4174 int rw = 0;
4175 int err = 0;
4176
4177 rc = alloc_reloc_control(fs_info);
4178 if (!rc)
4179 return -ENOMEM;
4180
4181 rc->extent_root = extent_root;
4182
4183 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4184 BUG_ON(!rc->block_group);
4185
4186 if (!rc->block_group->ro) {
4187 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4188 if (ret) {
4189 err = ret;
4190 goto out;
4191 }
4192 rw = 1;
4193 }
4194
4195 path = btrfs_alloc_path();
4196 if (!path) {
4197 err = -ENOMEM;
4198 goto out;
4199 }
4200
4201 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4202 path);
4203 btrfs_free_path(path);
4204
4205 if (!IS_ERR(inode))
4206 ret = delete_block_group_cache(fs_info, inode, 0);
4207 else
4208 ret = PTR_ERR(inode);
4209
4210 if (ret && ret != -ENOENT) {
4211 err = ret;
4212 goto out;
4213 }
4214
4215 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4216 if (IS_ERR(rc->data_inode)) {
4217 err = PTR_ERR(rc->data_inode);
4218 rc->data_inode = NULL;
4219 goto out;
4220 }
4221
4222 printk(KERN_INFO "btrfs: relocating block group %llu flags %llu\n",
4223 rc->block_group->key.objectid, rc->block_group->flags);
4224
4225 ret = btrfs_start_delalloc_roots(fs_info, 0);
4226 if (ret < 0) {
4227 err = ret;
4228 goto out;
4229 }
4230 btrfs_wait_ordered_roots(fs_info, -1);
4231
4232 while (1) {
4233 mutex_lock(&fs_info->cleaner_mutex);
4234 ret = relocate_block_group(rc);
4235 mutex_unlock(&fs_info->cleaner_mutex);
4236 if (ret < 0) {
4237 err = ret;
4238 goto out;
4239 }
4240
4241 if (rc->extents_found == 0)
4242 break;
4243
4244 printk(KERN_INFO "btrfs: found %llu extents\n",
4245 rc->extents_found);
4246
4247 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4248 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4249 (u64)-1);
4250 if (ret) {
4251 err = ret;
4252 goto out;
4253 }
4254 invalidate_mapping_pages(rc->data_inode->i_mapping,
4255 0, -1);
4256 rc->stage = UPDATE_DATA_PTRS;
4257 }
4258 }
4259
4260 filemap_write_and_wait_range(fs_info->btree_inode->i_mapping,
4261 rc->block_group->key.objectid,
4262 rc->block_group->key.objectid +
4263 rc->block_group->key.offset - 1);
4264
4265 WARN_ON(rc->block_group->pinned > 0);
4266 WARN_ON(rc->block_group->reserved > 0);
4267 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4268 out:
4269 if (err && rw)
4270 btrfs_set_block_group_rw(extent_root, rc->block_group);
4271 iput(rc->data_inode);
4272 btrfs_put_block_group(rc->block_group);
4273 kfree(rc);
4274 return err;
4275 }
4276
4277 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4278 {
4279 struct btrfs_trans_handle *trans;
4280 int ret, err;
4281
4282 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4283 if (IS_ERR(trans))
4284 return PTR_ERR(trans);
4285
4286 memset(&root->root_item.drop_progress, 0,
4287 sizeof(root->root_item.drop_progress));
4288 root->root_item.drop_level = 0;
4289 btrfs_set_root_refs(&root->root_item, 0);
4290 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4291 &root->root_key, &root->root_item);
4292
4293 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4294 if (err)
4295 return err;
4296 return ret;
4297 }
4298
4299 /*
4300 * recover relocation interrupted by system crash.
4301 *
4302 * this function resumes merging reloc trees with corresponding fs trees.
4303 * this is important for keeping the sharing of tree blocks
4304 */
4305 int btrfs_recover_relocation(struct btrfs_root *root)
4306 {
4307 LIST_HEAD(reloc_roots);
4308 struct btrfs_key key;
4309 struct btrfs_root *fs_root;
4310 struct btrfs_root *reloc_root;
4311 struct btrfs_path *path;
4312 struct extent_buffer *leaf;
4313 struct reloc_control *rc = NULL;
4314 struct btrfs_trans_handle *trans;
4315 int ret;
4316 int err = 0;
4317
4318 path = btrfs_alloc_path();
4319 if (!path)
4320 return -ENOMEM;
4321 path->reada = -1;
4322
4323 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4324 key.type = BTRFS_ROOT_ITEM_KEY;
4325 key.offset = (u64)-1;
4326
4327 while (1) {
4328 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4329 path, 0, 0);
4330 if (ret < 0) {
4331 err = ret;
4332 goto out;
4333 }
4334 if (ret > 0) {
4335 if (path->slots[0] == 0)
4336 break;
4337 path->slots[0]--;
4338 }
4339 leaf = path->nodes[0];
4340 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4341 btrfs_release_path(path);
4342
4343 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4344 key.type != BTRFS_ROOT_ITEM_KEY)
4345 break;
4346
4347 reloc_root = btrfs_read_fs_root(root, &key);
4348 if (IS_ERR(reloc_root)) {
4349 err = PTR_ERR(reloc_root);
4350 goto out;
4351 }
4352
4353 list_add(&reloc_root->root_list, &reloc_roots);
4354
4355 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4356 fs_root = read_fs_root(root->fs_info,
4357 reloc_root->root_key.offset);
4358 if (IS_ERR(fs_root)) {
4359 ret = PTR_ERR(fs_root);
4360 if (ret != -ENOENT) {
4361 err = ret;
4362 goto out;
4363 }
4364 ret = mark_garbage_root(reloc_root);
4365 if (ret < 0) {
4366 err = ret;
4367 goto out;
4368 }
4369 }
4370 }
4371
4372 if (key.offset == 0)
4373 break;
4374
4375 key.offset--;
4376 }
4377 btrfs_release_path(path);
4378
4379 if (list_empty(&reloc_roots))
4380 goto out;
4381
4382 rc = alloc_reloc_control(root->fs_info);
4383 if (!rc) {
4384 err = -ENOMEM;
4385 goto out;
4386 }
4387
4388 rc->extent_root = root->fs_info->extent_root;
4389
4390 set_reloc_control(rc);
4391
4392 trans = btrfs_join_transaction(rc->extent_root);
4393 if (IS_ERR(trans)) {
4394 unset_reloc_control(rc);
4395 err = PTR_ERR(trans);
4396 goto out_free;
4397 }
4398
4399 rc->merge_reloc_tree = 1;
4400
4401 while (!list_empty(&reloc_roots)) {
4402 reloc_root = list_entry(reloc_roots.next,
4403 struct btrfs_root, root_list);
4404 list_del(&reloc_root->root_list);
4405
4406 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4407 list_add_tail(&reloc_root->root_list,
4408 &rc->reloc_roots);
4409 continue;
4410 }
4411
4412 fs_root = read_fs_root(root->fs_info,
4413 reloc_root->root_key.offset);
4414 if (IS_ERR(fs_root)) {
4415 err = PTR_ERR(fs_root);
4416 goto out_free;
4417 }
4418
4419 err = __add_reloc_root(reloc_root);
4420 BUG_ON(err < 0); /* -ENOMEM or logic error */
4421 fs_root->reloc_root = reloc_root;
4422 }
4423
4424 err = btrfs_commit_transaction(trans, rc->extent_root);
4425 if (err)
4426 goto out_free;
4427
4428 merge_reloc_roots(rc);
4429
4430 unset_reloc_control(rc);
4431
4432 trans = btrfs_join_transaction(rc->extent_root);
4433 if (IS_ERR(trans))
4434 err = PTR_ERR(trans);
4435 else
4436 err = btrfs_commit_transaction(trans, rc->extent_root);
4437 out_free:
4438 kfree(rc);
4439 out:
4440 if (!list_empty(&reloc_roots))
4441 free_reloc_roots(&reloc_roots);
4442
4443 btrfs_free_path(path);
4444
4445 if (err == 0) {
4446 /* cleanup orphan inode in data relocation tree */
4447 fs_root = read_fs_root(root->fs_info,
4448 BTRFS_DATA_RELOC_TREE_OBJECTID);
4449 if (IS_ERR(fs_root))
4450 err = PTR_ERR(fs_root);
4451 else
4452 err = btrfs_orphan_cleanup(fs_root);
4453 }
4454 return err;
4455 }
4456
4457 /*
4458 * helper to add ordered checksum for data relocation.
4459 *
4460 * cloning checksum properly handles the nodatasum extents.
4461 * it also saves CPU time to re-calculate the checksum.
4462 */
4463 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4464 {
4465 struct btrfs_ordered_sum *sums;
4466 struct btrfs_ordered_extent *ordered;
4467 struct btrfs_root *root = BTRFS_I(inode)->root;
4468 int ret;
4469 u64 disk_bytenr;
4470 u64 new_bytenr;
4471 LIST_HEAD(list);
4472
4473 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4474 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4475
4476 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4477 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4478 disk_bytenr + len - 1, &list, 0);
4479 if (ret)
4480 goto out;
4481
4482 while (!list_empty(&list)) {
4483 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4484 list_del_init(&sums->list);
4485
4486 /*
4487 * We need to offset the new_bytenr based on where the csum is.
4488 * We need to do this because we will read in entire prealloc
4489 * extents but we may have written to say the middle of the
4490 * prealloc extent, so we need to make sure the csum goes with
4491 * the right disk offset.
4492 *
4493 * We can do this because the data reloc inode refers strictly
4494 * to the on disk bytes, so we don't have to worry about
4495 * disk_len vs real len like with real inodes since it's all
4496 * disk length.
4497 */
4498 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4499 sums->bytenr = new_bytenr;
4500
4501 btrfs_add_ordered_sum(inode, ordered, sums);
4502 }
4503 out:
4504 btrfs_put_ordered_extent(ordered);
4505 return ret;
4506 }
4507
4508 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4509 struct btrfs_root *root, struct extent_buffer *buf,
4510 struct extent_buffer *cow)
4511 {
4512 struct reloc_control *rc;
4513 struct backref_node *node;
4514 int first_cow = 0;
4515 int level;
4516 int ret = 0;
4517
4518 rc = root->fs_info->reloc_ctl;
4519 if (!rc)
4520 return 0;
4521
4522 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4523 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4524
4525 level = btrfs_header_level(buf);
4526 if (btrfs_header_generation(buf) <=
4527 btrfs_root_last_snapshot(&root->root_item))
4528 first_cow = 1;
4529
4530 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4531 rc->create_reloc_tree) {
4532 WARN_ON(!first_cow && level == 0);
4533
4534 node = rc->backref_cache.path[level];
4535 BUG_ON(node->bytenr != buf->start &&
4536 node->new_bytenr != buf->start);
4537
4538 drop_node_buffer(node);
4539 extent_buffer_get(cow);
4540 node->eb = cow;
4541 node->new_bytenr = cow->start;
4542
4543 if (!node->pending) {
4544 list_move_tail(&node->list,
4545 &rc->backref_cache.pending[level]);
4546 node->pending = 1;
4547 }
4548
4549 if (first_cow)
4550 __mark_block_processed(rc, node);
4551
4552 if (first_cow && level > 0)
4553 rc->nodes_relocated += buf->len;
4554 }
4555
4556 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4557 ret = replace_file_extents(trans, rc, root, cow);
4558 return ret;
4559 }
4560
4561 /*
4562 * called before creating snapshot. it calculates metadata reservation
4563 * requried for relocating tree blocks in the snapshot
4564 */
4565 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4566 struct btrfs_pending_snapshot *pending,
4567 u64 *bytes_to_reserve)
4568 {
4569 struct btrfs_root *root;
4570 struct reloc_control *rc;
4571
4572 root = pending->root;
4573 if (!root->reloc_root)
4574 return;
4575
4576 rc = root->fs_info->reloc_ctl;
4577 if (!rc->merge_reloc_tree)
4578 return;
4579
4580 root = root->reloc_root;
4581 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4582 /*
4583 * relocation is in the stage of merging trees. the space
4584 * used by merging a reloc tree is twice the size of
4585 * relocated tree nodes in the worst case. half for cowing
4586 * the reloc tree, half for cowing the fs tree. the space
4587 * used by cowing the reloc tree will be freed after the
4588 * tree is dropped. if we create snapshot, cowing the fs
4589 * tree may use more space than it frees. so we need
4590 * reserve extra space.
4591 */
4592 *bytes_to_reserve += rc->nodes_relocated;
4593 }
4594
4595 /*
4596 * called after snapshot is created. migrate block reservation
4597 * and create reloc root for the newly created snapshot
4598 */
4599 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4600 struct btrfs_pending_snapshot *pending)
4601 {
4602 struct btrfs_root *root = pending->root;
4603 struct btrfs_root *reloc_root;
4604 struct btrfs_root *new_root;
4605 struct reloc_control *rc;
4606 int ret;
4607
4608 if (!root->reloc_root)
4609 return 0;
4610
4611 rc = root->fs_info->reloc_ctl;
4612 rc->merging_rsv_size += rc->nodes_relocated;
4613
4614 if (rc->merge_reloc_tree) {
4615 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4616 rc->block_rsv,
4617 rc->nodes_relocated);
4618 if (ret)
4619 return ret;
4620 }
4621
4622 new_root = pending->snap;
4623 reloc_root = create_reloc_root(trans, root->reloc_root,
4624 new_root->root_key.objectid);
4625 if (IS_ERR(reloc_root))
4626 return PTR_ERR(reloc_root);
4627
4628 ret = __add_reloc_root(reloc_root);
4629 BUG_ON(ret < 0);
4630 new_root->reloc_root = reloc_root;
4631
4632 if (rc->create_reloc_tree)
4633 ret = clone_backref_node(trans, rc, root, reloc_root);
4634 return ret;
4635 }
Linux kernel - Deliverables
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