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Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
[linux-2.6/btrfs-unstable.git] / fs / btrfs / relocation.c
blob65245a07275baa37e8089e5e0901c924193d12da
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 #define RELOCATION_RESERVED_NODES 256
98
99 struct backref_cache {
100 /* red black tree of all backref nodes in the cache */
101 struct rb_root rb_root;
102 /* for passing backref nodes to btrfs_reloc_cow_block */
103 struct backref_node *path[BTRFS_MAX_LEVEL];
104 /*
105 * list of blocks that have been cowed but some block
106 * pointers in upper level blocks may not reflect the
107 * new location
108 */
109 struct list_head pending[BTRFS_MAX_LEVEL];
110 /* list of backref nodes with no child node */
111 struct list_head leaves;
112 /* list of blocks that have been cowed in current transaction */
113 struct list_head changed;
114 /* list of detached backref node. */
115 struct list_head detached;
116
117 u64 last_trans;
118
119 int nr_nodes;
120 int nr_edges;
121 };
122
123 /*
124 * map address of tree root to tree
125 */
126 struct mapping_node {
127 struct rb_node rb_node;
128 u64 bytenr;
129 void *data;
130 };
131
132 struct mapping_tree {
133 struct rb_root rb_root;
134 spinlock_t lock;
135 };
136
137 /*
138 * present a tree block to process
139 */
140 struct tree_block {
141 struct rb_node rb_node;
142 u64 bytenr;
143 struct btrfs_key key;
144 unsigned int level:8;
145 unsigned int key_ready:1;
146 };
147
148 #define MAX_EXTENTS 128
149
150 struct file_extent_cluster {
151 u64 start;
152 u64 end;
153 u64 boundary[MAX_EXTENTS];
154 unsigned int nr;
155 };
156
157 struct reloc_control {
158 /* block group to relocate */
159 struct btrfs_block_group_cache *block_group;
160 /* extent tree */
161 struct btrfs_root *extent_root;
162 /* inode for moving data */
163 struct inode *data_inode;
164
165 struct btrfs_block_rsv *block_rsv;
166
167 struct backref_cache backref_cache;
168
169 struct file_extent_cluster cluster;
170 /* tree blocks have been processed */
171 struct extent_io_tree processed_blocks;
172 /* map start of tree root to corresponding reloc tree */
173 struct mapping_tree reloc_root_tree;
174 /* list of reloc trees */
175 struct list_head reloc_roots;
176 /* size of metadata reservation for merging reloc trees */
177 u64 merging_rsv_size;
178 /* size of relocated tree nodes */
179 u64 nodes_relocated;
180 /* reserved size for block group relocation*/
181 u64 reserved_bytes;
182
183 u64 search_start;
184 u64 extents_found;
185
186 unsigned int stage:8;
187 unsigned int create_reloc_tree:1;
188 unsigned int merge_reloc_tree:1;
189 unsigned int found_file_extent:1;
190 };
191
192 /* stages of data relocation */
193 #define MOVE_DATA_EXTENTS 0
194 #define UPDATE_DATA_PTRS 1
195
196 static void remove_backref_node(struct backref_cache *cache,
197 struct backref_node *node);
198 static void __mark_block_processed(struct reloc_control *rc,
199 struct backref_node *node);
200
201 static void mapping_tree_init(struct mapping_tree *tree)
202 {
203 tree->rb_root = RB_ROOT;
204 spin_lock_init(&tree->lock);
205 }
206
207 static void backref_cache_init(struct backref_cache *cache)
208 {
209 int i;
210 cache->rb_root = RB_ROOT;
211 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
212 INIT_LIST_HEAD(&cache->pending[i]);
213 INIT_LIST_HEAD(&cache->changed);
214 INIT_LIST_HEAD(&cache->detached);
215 INIT_LIST_HEAD(&cache->leaves);
216 }
217
218 static void backref_cache_cleanup(struct backref_cache *cache)
219 {
220 struct backref_node *node;
221 int i;
222
223 while (!list_empty(&cache->detached)) {
224 node = list_entry(cache->detached.next,
225 struct backref_node, list);
226 remove_backref_node(cache, node);
227 }
228
229 while (!list_empty(&cache->leaves)) {
230 node = list_entry(cache->leaves.next,
231 struct backref_node, lower);
232 remove_backref_node(cache, node);
233 }
234
235 cache->last_trans = 0;
236
237 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
238 BUG_ON(!list_empty(&cache->pending[i]));
239 BUG_ON(!list_empty(&cache->changed));
240 BUG_ON(!list_empty(&cache->detached));
241 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
242 BUG_ON(cache->nr_nodes);
243 BUG_ON(cache->nr_edges);
244 }
245
246 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
247 {
248 struct backref_node *node;
249
250 node = kzalloc(sizeof(*node), GFP_NOFS);
251 if (node) {
252 INIT_LIST_HEAD(&node->list);
253 INIT_LIST_HEAD(&node->upper);
254 INIT_LIST_HEAD(&node->lower);
255 RB_CLEAR_NODE(&node->rb_node);
256 cache->nr_nodes++;
257 }
258 return node;
259 }
260
261 static void free_backref_node(struct backref_cache *cache,
262 struct backref_node *node)
263 {
264 if (node) {
265 cache->nr_nodes--;
266 kfree(node);
267 }
268 }
269
270 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
271 {
272 struct backref_edge *edge;
273
274 edge = kzalloc(sizeof(*edge), GFP_NOFS);
275 if (edge)
276 cache->nr_edges++;
277 return edge;
278 }
279
280 static void free_backref_edge(struct backref_cache *cache,
281 struct backref_edge *edge)
282 {
283 if (edge) {
284 cache->nr_edges--;
285 kfree(edge);
286 }
287 }
288
289 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
290 struct rb_node *node)
291 {
292 struct rb_node **p = &root->rb_node;
293 struct rb_node *parent = NULL;
294 struct tree_entry *entry;
295
296 while (*p) {
297 parent = *p;
298 entry = rb_entry(parent, struct tree_entry, rb_node);
299
300 if (bytenr < entry->bytenr)
301 p = &(*p)->rb_left;
302 else if (bytenr > entry->bytenr)
303 p = &(*p)->rb_right;
304 else
305 return parent;
306 }
307
308 rb_link_node(node, parent, p);
309 rb_insert_color(node, root);
310 return NULL;
311 }
312
313 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
314 {
315 struct rb_node *n = root->rb_node;
316 struct tree_entry *entry;
317
318 while (n) {
319 entry = rb_entry(n, struct tree_entry, rb_node);
320
321 if (bytenr < entry->bytenr)
322 n = n->rb_left;
323 else if (bytenr > entry->bytenr)
324 n = n->rb_right;
325 else
326 return n;
327 }
328 return NULL;
329 }
330
331 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
332 {
333
334 struct btrfs_fs_info *fs_info = NULL;
335 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
336 rb_node);
337 if (bnode->root)
338 fs_info = bnode->root->fs_info;
339 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
340 "found at offset %llu", bytenr);
341 }
342
343 /*
344 * walk up backref nodes until reach node presents tree root
345 */
346 static struct backref_node *walk_up_backref(struct backref_node *node,
347 struct backref_edge *edges[],
348 int *index)
349 {
350 struct backref_edge *edge;
351 int idx = *index;
352
353 while (!list_empty(&node->upper)) {
354 edge = list_entry(node->upper.next,
355 struct backref_edge, list[LOWER]);
356 edges[idx++] = edge;
357 node = edge->node[UPPER];
358 }
359 BUG_ON(node->detached);
360 *index = idx;
361 return node;
362 }
363
364 /*
365 * walk down backref nodes to find start of next reference path
366 */
367 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
368 int *index)
369 {
370 struct backref_edge *edge;
371 struct backref_node *lower;
372 int idx = *index;
373
374 while (idx > 0) {
375 edge = edges[idx - 1];
376 lower = edge->node[LOWER];
377 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
378 idx--;
379 continue;
380 }
381 edge = list_entry(edge->list[LOWER].next,
382 struct backref_edge, list[LOWER]);
383 edges[idx - 1] = edge;
384 *index = idx;
385 return edge->node[UPPER];
386 }
387 *index = 0;
388 return NULL;
389 }
390
391 static void unlock_node_buffer(struct backref_node *node)
392 {
393 if (node->locked) {
394 btrfs_tree_unlock(node->eb);
395 node->locked = 0;
396 }
397 }
398
399 static void drop_node_buffer(struct backref_node *node)
400 {
401 if (node->eb) {
402 unlock_node_buffer(node);
403 free_extent_buffer(node->eb);
404 node->eb = NULL;
405 }
406 }
407
408 static void drop_backref_node(struct backref_cache *tree,
409 struct backref_node *node)
410 {
411 BUG_ON(!list_empty(&node->upper));
412
413 drop_node_buffer(node);
414 list_del(&node->list);
415 list_del(&node->lower);
416 if (!RB_EMPTY_NODE(&node->rb_node))
417 rb_erase(&node->rb_node, &tree->rb_root);
418 free_backref_node(tree, node);
419 }
420
421 /*
422 * remove a backref node from the backref cache
423 */
424 static void remove_backref_node(struct backref_cache *cache,
425 struct backref_node *node)
426 {
427 struct backref_node *upper;
428 struct backref_edge *edge;
429
430 if (!node)
431 return;
432
433 BUG_ON(!node->lowest && !node->detached);
434 while (!list_empty(&node->upper)) {
435 edge = list_entry(node->upper.next, struct backref_edge,
436 list[LOWER]);
437 upper = edge->node[UPPER];
438 list_del(&edge->list[LOWER]);
439 list_del(&edge->list[UPPER]);
440 free_backref_edge(cache, edge);
441
442 if (RB_EMPTY_NODE(&upper->rb_node)) {
443 BUG_ON(!list_empty(&node->upper));
444 drop_backref_node(cache, node);
445 node = upper;
446 node->lowest = 1;
447 continue;
448 }
449 /*
450 * add the node to leaf node list if no other
451 * child block cached.
452 */
453 if (list_empty(&upper->lower)) {
454 list_add_tail(&upper->lower, &cache->leaves);
455 upper->lowest = 1;
456 }
457 }
458
459 drop_backref_node(cache, node);
460 }
461
462 static void update_backref_node(struct backref_cache *cache,
463 struct backref_node *node, u64 bytenr)
464 {
465 struct rb_node *rb_node;
466 rb_erase(&node->rb_node, &cache->rb_root);
467 node->bytenr = bytenr;
468 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
469 if (rb_node)
470 backref_tree_panic(rb_node, -EEXIST, bytenr);
471 }
472
473 /*
474 * update backref cache after a transaction commit
475 */
476 static int update_backref_cache(struct btrfs_trans_handle *trans,
477 struct backref_cache *cache)
478 {
479 struct backref_node *node;
480 int level = 0;
481
482 if (cache->last_trans == 0) {
483 cache->last_trans = trans->transid;
484 return 0;
485 }
486
487 if (cache->last_trans == trans->transid)
488 return 0;
489
490 /*
491 * detached nodes are used to avoid unnecessary backref
492 * lookup. transaction commit changes the extent tree.
493 * so the detached nodes are no longer useful.
494 */
495 while (!list_empty(&cache->detached)) {
496 node = list_entry(cache->detached.next,
497 struct backref_node, list);
498 remove_backref_node(cache, node);
499 }
500
501 while (!list_empty(&cache->changed)) {
502 node = list_entry(cache->changed.next,
503 struct backref_node, list);
504 list_del_init(&node->list);
505 BUG_ON(node->pending);
506 update_backref_node(cache, node, node->new_bytenr);
507 }
508
509 /*
510 * some nodes can be left in the pending list if there were
511 * errors during processing the pending nodes.
512 */
513 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
514 list_for_each_entry(node, &cache->pending[level], list) {
515 BUG_ON(!node->pending);
516 if (node->bytenr == node->new_bytenr)
517 continue;
518 update_backref_node(cache, node, node->new_bytenr);
519 }
520 }
521
522 cache->last_trans = 0;
523 return 1;
524 }
525
526
527 static int should_ignore_root(struct btrfs_root *root)
528 {
529 struct btrfs_root *reloc_root;
530
531 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
532 return 0;
533
534 reloc_root = root->reloc_root;
535 if (!reloc_root)
536 return 0;
537
538 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
539 root->fs_info->running_transaction->transid - 1)
540 return 0;
541 /*
542 * if there is reloc tree and it was created in previous
543 * transaction backref lookup can find the reloc tree,
544 * so backref node for the fs tree root is useless for
545 * relocation.
546 */
547 return 1;
548 }
549 /*
550 * find reloc tree by address of tree root
551 */
552 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
553 u64 bytenr)
554 {
555 struct rb_node *rb_node;
556 struct mapping_node *node;
557 struct btrfs_root *root = NULL;
558
559 spin_lock(&rc->reloc_root_tree.lock);
560 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
561 if (rb_node) {
562 node = rb_entry(rb_node, struct mapping_node, rb_node);
563 root = (struct btrfs_root *)node->data;
564 }
565 spin_unlock(&rc->reloc_root_tree.lock);
566 return root;
567 }
568
569 static int is_cowonly_root(u64 root_objectid)
570 {
571 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
572 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
573 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
574 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
575 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
576 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
577 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
578 root_objectid == BTRFS_QUOTA_TREE_OBJECTID)
579 return 1;
580 return 0;
581 }
582
583 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
584 u64 root_objectid)
585 {
586 struct btrfs_key key;
587
588 key.objectid = root_objectid;
589 key.type = BTRFS_ROOT_ITEM_KEY;
590 if (is_cowonly_root(root_objectid))
591 key.offset = 0;
592 else
593 key.offset = (u64)-1;
594
595 return btrfs_get_fs_root(fs_info, &key, false);
596 }
597
598 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
599 static noinline_for_stack
600 struct btrfs_root *find_tree_root(struct reloc_control *rc,
601 struct extent_buffer *leaf,
602 struct btrfs_extent_ref_v0 *ref0)
603 {
604 struct btrfs_root *root;
605 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
606 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
607
608 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
609
610 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
611 BUG_ON(IS_ERR(root));
612
613 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
614 generation != btrfs_root_generation(&root->root_item))
615 return NULL;
616
617 return root;
618 }
619 #endif
620
621 static noinline_for_stack
622 int find_inline_backref(struct extent_buffer *leaf, int slot,
623 unsigned long *ptr, unsigned long *end)
624 {
625 struct btrfs_key key;
626 struct btrfs_extent_item *ei;
627 struct btrfs_tree_block_info *bi;
628 u32 item_size;
629
630 btrfs_item_key_to_cpu(leaf, &key, slot);
631
632 item_size = btrfs_item_size_nr(leaf, slot);
633 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
634 if (item_size < sizeof(*ei)) {
635 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
636 return 1;
637 }
638 #endif
639 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
640 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
641 BTRFS_EXTENT_FLAG_TREE_BLOCK));
642
643 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
644 item_size <= sizeof(*ei) + sizeof(*bi)) {
645 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
646 return 1;
647 }
648 if (key.type == BTRFS_METADATA_ITEM_KEY &&
649 item_size <= sizeof(*ei)) {
650 WARN_ON(item_size < sizeof(*ei));
651 return 1;
652 }
653
654 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
655 bi = (struct btrfs_tree_block_info *)(ei + 1);
656 *ptr = (unsigned long)(bi + 1);
657 } else {
658 *ptr = (unsigned long)(ei + 1);
659 }
660 *end = (unsigned long)ei + item_size;
661 return 0;
662 }
663
664 /*
665 * build backref tree for a given tree block. root of the backref tree
666 * corresponds the tree block, leaves of the backref tree correspond
667 * roots of b-trees that reference the tree block.
668 *
669 * the basic idea of this function is check backrefs of a given block
670 * to find upper level blocks that refernece the block, and then check
671 * bakcrefs of these upper level blocks recursively. the recursion stop
672 * when tree root is reached or backrefs for the block is cached.
673 *
674 * NOTE: if we find backrefs for a block are cached, we know backrefs
675 * for all upper level blocks that directly/indirectly reference the
676 * block are also cached.
677 */
678 static noinline_for_stack
679 struct backref_node *build_backref_tree(struct reloc_control *rc,
680 struct btrfs_key *node_key,
681 int level, u64 bytenr)
682 {
683 struct backref_cache *cache = &rc->backref_cache;
684 struct btrfs_path *path1;
685 struct btrfs_path *path2;
686 struct extent_buffer *eb;
687 struct btrfs_root *root;
688 struct backref_node *cur;
689 struct backref_node *upper;
690 struct backref_node *lower;
691 struct backref_node *node = NULL;
692 struct backref_node *exist = NULL;
693 struct backref_edge *edge;
694 struct rb_node *rb_node;
695 struct btrfs_key key;
696 unsigned long end;
697 unsigned long ptr;
698 LIST_HEAD(list);
699 LIST_HEAD(useless);
700 int cowonly;
701 int ret;
702 int err = 0;
703 bool need_check = true;
704
705 path1 = btrfs_alloc_path();
706 path2 = btrfs_alloc_path();
707 if (!path1 || !path2) {
708 err = -ENOMEM;
709 goto out;
710 }
711 path1->reada = 1;
712 path2->reada = 2;
713
714 node = alloc_backref_node(cache);
715 if (!node) {
716 err = -ENOMEM;
717 goto out;
718 }
719
720 node->bytenr = bytenr;
721 node->level = level;
722 node->lowest = 1;
723 cur = node;
724 again:
725 end = 0;
726 ptr = 0;
727 key.objectid = cur->bytenr;
728 key.type = BTRFS_METADATA_ITEM_KEY;
729 key.offset = (u64)-1;
730
731 path1->search_commit_root = 1;
732 path1->skip_locking = 1;
733 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
734 0, 0);
735 if (ret < 0) {
736 err = ret;
737 goto out;
738 }
739 BUG_ON(!ret || !path1->slots[0]);
740
741 path1->slots[0]--;
742
743 WARN_ON(cur->checked);
744 if (!list_empty(&cur->upper)) {
745 /*
746 * the backref was added previously when processing
747 * backref of type BTRFS_TREE_BLOCK_REF_KEY
748 */
749 BUG_ON(!list_is_singular(&cur->upper));
750 edge = list_entry(cur->upper.next, struct backref_edge,
751 list[LOWER]);
752 BUG_ON(!list_empty(&edge->list[UPPER]));
753 exist = edge->node[UPPER];
754 /*
755 * add the upper level block to pending list if we need
756 * check its backrefs
757 */
758 if (!exist->checked)
759 list_add_tail(&edge->list[UPPER], &list);
760 } else {
761 exist = NULL;
762 }
763
764 while (1) {
765 cond_resched();
766 eb = path1->nodes[0];
767
768 if (ptr >= end) {
769 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
770 ret = btrfs_next_leaf(rc->extent_root, path1);
771 if (ret < 0) {
772 err = ret;
773 goto out;
774 }
775 if (ret > 0)
776 break;
777 eb = path1->nodes[0];
778 }
779
780 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
781 if (key.objectid != cur->bytenr) {
782 WARN_ON(exist);
783 break;
784 }
785
786 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
787 key.type == BTRFS_METADATA_ITEM_KEY) {
788 ret = find_inline_backref(eb, path1->slots[0],
789 &ptr, &end);
790 if (ret)
791 goto next;
792 }
793 }
794
795 if (ptr < end) {
796 /* update key for inline back ref */
797 struct btrfs_extent_inline_ref *iref;
798 iref = (struct btrfs_extent_inline_ref *)ptr;
799 key.type = btrfs_extent_inline_ref_type(eb, iref);
800 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
801 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
802 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
803 }
804
805 if (exist &&
806 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
807 exist->owner == key.offset) ||
808 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
809 exist->bytenr == key.offset))) {
810 exist = NULL;
811 goto next;
812 }
813
814 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
815 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
816 key.type == BTRFS_EXTENT_REF_V0_KEY) {
817 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
818 struct btrfs_extent_ref_v0 *ref0;
819 ref0 = btrfs_item_ptr(eb, path1->slots[0],
820 struct btrfs_extent_ref_v0);
821 if (key.objectid == key.offset) {
822 root = find_tree_root(rc, eb, ref0);
823 if (root && !should_ignore_root(root))
824 cur->root = root;
825 else
826 list_add(&cur->list, &useless);
827 break;
828 }
829 if (is_cowonly_root(btrfs_ref_root_v0(eb,
830 ref0)))
831 cur->cowonly = 1;
832 }
833 #else
834 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
835 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
836 #endif
837 if (key.objectid == key.offset) {
838 /*
839 * only root blocks of reloc trees use
840 * backref of this type.
841 */
842 root = find_reloc_root(rc, cur->bytenr);
843 BUG_ON(!root);
844 cur->root = root;
845 break;
846 }
847
848 edge = alloc_backref_edge(cache);
849 if (!edge) {
850 err = -ENOMEM;
851 goto out;
852 }
853 rb_node = tree_search(&cache->rb_root, key.offset);
854 if (!rb_node) {
855 upper = alloc_backref_node(cache);
856 if (!upper) {
857 free_backref_edge(cache, edge);
858 err = -ENOMEM;
859 goto out;
860 }
861 upper->bytenr = key.offset;
862 upper->level = cur->level + 1;
863 /*
864 * backrefs for the upper level block isn't
865 * cached, add the block to pending list
866 */
867 list_add_tail(&edge->list[UPPER], &list);
868 } else {
869 upper = rb_entry(rb_node, struct backref_node,
870 rb_node);
871 BUG_ON(!upper->checked);
872 INIT_LIST_HEAD(&edge->list[UPPER]);
873 }
874 list_add_tail(&edge->list[LOWER], &cur->upper);
875 edge->node[LOWER] = cur;
876 edge->node[UPPER] = upper;
877
878 goto next;
879 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
880 goto next;
881 }
882
883 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
884 root = read_fs_root(rc->extent_root->fs_info, key.offset);
885 if (IS_ERR(root)) {
886 err = PTR_ERR(root);
887 goto out;
888 }
889
890 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
891 cur->cowonly = 1;
892
893 if (btrfs_root_level(&root->root_item) == cur->level) {
894 /* tree root */
895 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
896 cur->bytenr);
897 if (should_ignore_root(root))
898 list_add(&cur->list, &useless);
899 else
900 cur->root = root;
901 break;
902 }
903
904 level = cur->level + 1;
905
906 /*
907 * searching the tree to find upper level blocks
908 * reference the block.
909 */
910 path2->search_commit_root = 1;
911 path2->skip_locking = 1;
912 path2->lowest_level = level;
913 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
914 path2->lowest_level = 0;
915 if (ret < 0) {
916 err = ret;
917 goto out;
918 }
919 if (ret > 0 && path2->slots[level] > 0)
920 path2->slots[level]--;
921
922 eb = path2->nodes[level];
923 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
924 cur->bytenr);
925
926 lower = cur;
927 need_check = true;
928 for (; level < BTRFS_MAX_LEVEL; level++) {
929 if (!path2->nodes[level]) {
930 BUG_ON(btrfs_root_bytenr(&root->root_item) !=
931 lower->bytenr);
932 if (should_ignore_root(root))
933 list_add(&lower->list, &useless);
934 else
935 lower->root = root;
936 break;
937 }
938
939 edge = alloc_backref_edge(cache);
940 if (!edge) {
941 err = -ENOMEM;
942 goto out;
943 }
944
945 eb = path2->nodes[level];
946 rb_node = tree_search(&cache->rb_root, eb->start);
947 if (!rb_node) {
948 upper = alloc_backref_node(cache);
949 if (!upper) {
950 free_backref_edge(cache, edge);
951 err = -ENOMEM;
952 goto out;
953 }
954 upper->bytenr = eb->start;
955 upper->owner = btrfs_header_owner(eb);
956 upper->level = lower->level + 1;
957 if (!test_bit(BTRFS_ROOT_REF_COWS,
958 &root->state))
959 upper->cowonly = 1;
960
961 /*
962 * if we know the block isn't shared
963 * we can void checking its backrefs.
964 */
965 if (btrfs_block_can_be_shared(root, eb))
966 upper->checked = 0;
967 else
968 upper->checked = 1;
969
970 /*
971 * add the block to pending list if we
972 * need check its backrefs, we only do this once
973 * while walking up a tree as we will catch
974 * anything else later on.
975 */
976 if (!upper->checked && need_check) {
977 need_check = false;
978 list_add_tail(&edge->list[UPPER],
979 &list);
980 } else
981 INIT_LIST_HEAD(&edge->list[UPPER]);
982 } else {
983 upper = rb_entry(rb_node, struct backref_node,
984 rb_node);
985 BUG_ON(!upper->checked);
986 INIT_LIST_HEAD(&edge->list[UPPER]);
987 if (!upper->owner)
988 upper->owner = btrfs_header_owner(eb);
989 }
990 list_add_tail(&edge->list[LOWER], &lower->upper);
991 edge->node[LOWER] = lower;
992 edge->node[UPPER] = upper;
993
994 if (rb_node)
995 break;
996 lower = upper;
997 upper = NULL;
998 }
999 btrfs_release_path(path2);
1000 next:
1001 if (ptr < end) {
1002 ptr += btrfs_extent_inline_ref_size(key.type);
1003 if (ptr >= end) {
1004 WARN_ON(ptr > end);
1005 ptr = 0;
1006 end = 0;
1007 }
1008 }
1009 if (ptr >= end)
1010 path1->slots[0]++;
1011 }
1012 btrfs_release_path(path1);
1013
1014 cur->checked = 1;
1015 WARN_ON(exist);
1016
1017 /* the pending list isn't empty, take the first block to process */
1018 if (!list_empty(&list)) {
1019 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1020 list_del_init(&edge->list[UPPER]);
1021 cur = edge->node[UPPER];
1022 goto again;
1023 }
1024
1025 /*
1026 * everything goes well, connect backref nodes and insert backref nodes
1027 * into the cache.
1028 */
1029 BUG_ON(!node->checked);
1030 cowonly = node->cowonly;
1031 if (!cowonly) {
1032 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1033 &node->rb_node);
1034 if (rb_node)
1035 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1036 list_add_tail(&node->lower, &cache->leaves);
1037 }
1038
1039 list_for_each_entry(edge, &node->upper, list[LOWER])
1040 list_add_tail(&edge->list[UPPER], &list);
1041
1042 while (!list_empty(&list)) {
1043 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1044 list_del_init(&edge->list[UPPER]);
1045 upper = edge->node[UPPER];
1046 if (upper->detached) {
1047 list_del(&edge->list[LOWER]);
1048 lower = edge->node[LOWER];
1049 free_backref_edge(cache, edge);
1050 if (list_empty(&lower->upper))
1051 list_add(&lower->list, &useless);
1052 continue;
1053 }
1054
1055 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1056 if (upper->lowest) {
1057 list_del_init(&upper->lower);
1058 upper->lowest = 0;
1059 }
1060
1061 list_add_tail(&edge->list[UPPER], &upper->lower);
1062 continue;
1063 }
1064
1065 BUG_ON(!upper->checked);
1066 BUG_ON(cowonly != upper->cowonly);
1067 if (!cowonly) {
1068 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1069 &upper->rb_node);
1070 if (rb_node)
1071 backref_tree_panic(rb_node, -EEXIST,
1072 upper->bytenr);
1073 }
1074
1075 list_add_tail(&edge->list[UPPER], &upper->lower);
1076
1077 list_for_each_entry(edge, &upper->upper, list[LOWER])
1078 list_add_tail(&edge->list[UPPER], &list);
1079 }
1080 /*
1081 * process useless backref nodes. backref nodes for tree leaves
1082 * are deleted from the cache. backref nodes for upper level
1083 * tree blocks are left in the cache to avoid unnecessary backref
1084 * lookup.
1085 */
1086 while (!list_empty(&useless)) {
1087 upper = list_entry(useless.next, struct backref_node, list);
1088 list_del_init(&upper->list);
1089 BUG_ON(!list_empty(&upper->upper));
1090 if (upper == node)
1091 node = NULL;
1092 if (upper->lowest) {
1093 list_del_init(&upper->lower);
1094 upper->lowest = 0;
1095 }
1096 while (!list_empty(&upper->lower)) {
1097 edge = list_entry(upper->lower.next,
1098 struct backref_edge, list[UPPER]);
1099 list_del(&edge->list[UPPER]);
1100 list_del(&edge->list[LOWER]);
1101 lower = edge->node[LOWER];
1102 free_backref_edge(cache, edge);
1103
1104 if (list_empty(&lower->upper))
1105 list_add(&lower->list, &useless);
1106 }
1107 __mark_block_processed(rc, upper);
1108 if (upper->level > 0) {
1109 list_add(&upper->list, &cache->detached);
1110 upper->detached = 1;
1111 } else {
1112 rb_erase(&upper->rb_node, &cache->rb_root);
1113 free_backref_node(cache, upper);
1114 }
1115 }
1116 out:
1117 btrfs_free_path(path1);
1118 btrfs_free_path(path2);
1119 if (err) {
1120 while (!list_empty(&useless)) {
1121 lower = list_entry(useless.next,
1122 struct backref_node, upper);
1123 list_del_init(&lower->upper);
1124 }
1125 upper = node;
1126 INIT_LIST_HEAD(&list);
1127 while (upper) {
1128 if (RB_EMPTY_NODE(&upper->rb_node)) {
1129 list_splice_tail(&upper->upper, &list);
1130 free_backref_node(cache, upper);
1131 }
1132
1133 if (list_empty(&list))
1134 break;
1135
1136 edge = list_entry(list.next, struct backref_edge,
1137 list[LOWER]);
1138 list_del(&edge->list[LOWER]);
1139 upper = edge->node[UPPER];
1140 free_backref_edge(cache, edge);
1141 }
1142 return ERR_PTR(err);
1143 }
1144 BUG_ON(node && node->detached);
1145 return node;
1146 }
1147
1148 /*
1149 * helper to add backref node for the newly created snapshot.
1150 * the backref node is created by cloning backref node that
1151 * corresponds to root of source tree
1152 */
1153 static int clone_backref_node(struct btrfs_trans_handle *trans,
1154 struct reloc_control *rc,
1155 struct btrfs_root *src,
1156 struct btrfs_root *dest)
1157 {
1158 struct btrfs_root *reloc_root = src->reloc_root;
1159 struct backref_cache *cache = &rc->backref_cache;
1160 struct backref_node *node = NULL;
1161 struct backref_node *new_node;
1162 struct backref_edge *edge;
1163 struct backref_edge *new_edge;
1164 struct rb_node *rb_node;
1165
1166 if (cache->last_trans > 0)
1167 update_backref_cache(trans, cache);
1168
1169 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1170 if (rb_node) {
1171 node = rb_entry(rb_node, struct backref_node, rb_node);
1172 if (node->detached)
1173 node = NULL;
1174 else
1175 BUG_ON(node->new_bytenr != reloc_root->node->start);
1176 }
1177
1178 if (!node) {
1179 rb_node = tree_search(&cache->rb_root,
1180 reloc_root->commit_root->start);
1181 if (rb_node) {
1182 node = rb_entry(rb_node, struct backref_node,
1183 rb_node);
1184 BUG_ON(node->detached);
1185 }
1186 }
1187
1188 if (!node)
1189 return 0;
1190
1191 new_node = alloc_backref_node(cache);
1192 if (!new_node)
1193 return -ENOMEM;
1194
1195 new_node->bytenr = dest->node->start;
1196 new_node->level = node->level;
1197 new_node->lowest = node->lowest;
1198 new_node->checked = 1;
1199 new_node->root = dest;
1200
1201 if (!node->lowest) {
1202 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1203 new_edge = alloc_backref_edge(cache);
1204 if (!new_edge)
1205 goto fail;
1206
1207 new_edge->node[UPPER] = new_node;
1208 new_edge->node[LOWER] = edge->node[LOWER];
1209 list_add_tail(&new_edge->list[UPPER],
1210 &new_node->lower);
1211 }
1212 } else {
1213 list_add_tail(&new_node->lower, &cache->leaves);
1214 }
1215
1216 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1217 &new_node->rb_node);
1218 if (rb_node)
1219 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1220
1221 if (!new_node->lowest) {
1222 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1223 list_add_tail(&new_edge->list[LOWER],
1224 &new_edge->node[LOWER]->upper);
1225 }
1226 }
1227 return 0;
1228 fail:
1229 while (!list_empty(&new_node->lower)) {
1230 new_edge = list_entry(new_node->lower.next,
1231 struct backref_edge, list[UPPER]);
1232 list_del(&new_edge->list[UPPER]);
1233 free_backref_edge(cache, new_edge);
1234 }
1235 free_backref_node(cache, new_node);
1236 return -ENOMEM;
1237 }
1238
1239 /*
1240 * helper to add 'address of tree root -> reloc tree' mapping
1241 */
1242 static int __must_check __add_reloc_root(struct btrfs_root *root)
1243 {
1244 struct rb_node *rb_node;
1245 struct mapping_node *node;
1246 struct reloc_control *rc = root->fs_info->reloc_ctl;
1247
1248 node = kmalloc(sizeof(*node), GFP_NOFS);
1249 if (!node)
1250 return -ENOMEM;
1251
1252 node->bytenr = root->node->start;
1253 node->data = root;
1254
1255 spin_lock(&rc->reloc_root_tree.lock);
1256 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1257 node->bytenr, &node->rb_node);
1258 spin_unlock(&rc->reloc_root_tree.lock);
1259 if (rb_node) {
1260 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1261 "for start=%llu while inserting into relocation "
1262 "tree", node->bytenr);
1263 kfree(node);
1264 return -EEXIST;
1265 }
1266
1267 list_add_tail(&root->root_list, &rc->reloc_roots);
1268 return 0;
1269 }
1270
1271 /*
1272 * helper to delete the 'address of tree root -> reloc tree'
1273 * mapping
1274 */
1275 static void __del_reloc_root(struct btrfs_root *root)
1276 {
1277 struct rb_node *rb_node;
1278 struct mapping_node *node = NULL;
1279 struct reloc_control *rc = root->fs_info->reloc_ctl;
1280
1281 spin_lock(&rc->reloc_root_tree.lock);
1282 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1283 root->node->start);
1284 if (rb_node) {
1285 node = rb_entry(rb_node, struct mapping_node, rb_node);
1286 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1287 }
1288 spin_unlock(&rc->reloc_root_tree.lock);
1289
1290 if (!node)
1291 return;
1292 BUG_ON((struct btrfs_root *)node->data != root);
1293
1294 spin_lock(&root->fs_info->trans_lock);
1295 list_del_init(&root->root_list);
1296 spin_unlock(&root->fs_info->trans_lock);
1297 kfree(node);
1298 }
1299
1300 /*
1301 * helper to update the 'address of tree root -> reloc tree'
1302 * mapping
1303 */
1304 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1305 {
1306 struct rb_node *rb_node;
1307 struct mapping_node *node = NULL;
1308 struct reloc_control *rc = root->fs_info->reloc_ctl;
1309
1310 spin_lock(&rc->reloc_root_tree.lock);
1311 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1312 root->node->start);
1313 if (rb_node) {
1314 node = rb_entry(rb_node, struct mapping_node, rb_node);
1315 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1316 }
1317 spin_unlock(&rc->reloc_root_tree.lock);
1318
1319 if (!node)
1320 return 0;
1321 BUG_ON((struct btrfs_root *)node->data != root);
1322
1323 spin_lock(&rc->reloc_root_tree.lock);
1324 node->bytenr = new_bytenr;
1325 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1326 node->bytenr, &node->rb_node);
1327 spin_unlock(&rc->reloc_root_tree.lock);
1328 if (rb_node)
1329 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1330 return 0;
1331 }
1332
1333 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1334 struct btrfs_root *root, u64 objectid)
1335 {
1336 struct btrfs_root *reloc_root;
1337 struct extent_buffer *eb;
1338 struct btrfs_root_item *root_item;
1339 struct btrfs_key root_key;
1340 u64 last_snap = 0;
1341 int ret;
1342
1343 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1344 BUG_ON(!root_item);
1345
1346 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1347 root_key.type = BTRFS_ROOT_ITEM_KEY;
1348 root_key.offset = objectid;
1349
1350 if (root->root_key.objectid == objectid) {
1351 /* called by btrfs_init_reloc_root */
1352 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1353 BTRFS_TREE_RELOC_OBJECTID);
1354 BUG_ON(ret);
1355
1356 last_snap = btrfs_root_last_snapshot(&root->root_item);
1357 btrfs_set_root_last_snapshot(&root->root_item,
1358 trans->transid - 1);
1359 } else {
1360 /*
1361 * called by btrfs_reloc_post_snapshot_hook.
1362 * the source tree is a reloc tree, all tree blocks
1363 * modified after it was created have RELOC flag
1364 * set in their headers. so it's OK to not update
1365 * the 'last_snapshot'.
1366 */
1367 ret = btrfs_copy_root(trans, root, root->node, &eb,
1368 BTRFS_TREE_RELOC_OBJECTID);
1369 BUG_ON(ret);
1370 }
1371
1372 memcpy(root_item, &root->root_item, sizeof(*root_item));
1373 btrfs_set_root_bytenr(root_item, eb->start);
1374 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1375 btrfs_set_root_generation(root_item, trans->transid);
1376
1377 if (root->root_key.objectid == objectid) {
1378 btrfs_set_root_refs(root_item, 0);
1379 memset(&root_item->drop_progress, 0,
1380 sizeof(struct btrfs_disk_key));
1381 root_item->drop_level = 0;
1382 /*
1383 * abuse rtransid, it is safe because it is impossible to
1384 * receive data into a relocation tree.
1385 */
1386 btrfs_set_root_rtransid(root_item, last_snap);
1387 btrfs_set_root_otransid(root_item, trans->transid);
1388 }
1389
1390 btrfs_tree_unlock(eb);
1391 free_extent_buffer(eb);
1392
1393 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1394 &root_key, root_item);
1395 BUG_ON(ret);
1396 kfree(root_item);
1397
1398 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1399 BUG_ON(IS_ERR(reloc_root));
1400 reloc_root->last_trans = trans->transid;
1401 return reloc_root;
1402 }
1403
1404 /*
1405 * create reloc tree for a given fs tree. reloc tree is just a
1406 * snapshot of the fs tree with special root objectid.
1407 */
1408 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1409 struct btrfs_root *root)
1410 {
1411 struct btrfs_root *reloc_root;
1412 struct reloc_control *rc = root->fs_info->reloc_ctl;
1413 struct btrfs_block_rsv *rsv;
1414 int clear_rsv = 0;
1415 int ret;
1416
1417 if (root->reloc_root) {
1418 reloc_root = root->reloc_root;
1419 reloc_root->last_trans = trans->transid;
1420 return 0;
1421 }
1422
1423 if (!rc || !rc->create_reloc_tree ||
1424 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1425 return 0;
1426
1427 if (!trans->reloc_reserved) {
1428 rsv = trans->block_rsv;
1429 trans->block_rsv = rc->block_rsv;
1430 clear_rsv = 1;
1431 }
1432 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1433 if (clear_rsv)
1434 trans->block_rsv = rsv;
1435
1436 ret = __add_reloc_root(reloc_root);
1437 BUG_ON(ret < 0);
1438 root->reloc_root = reloc_root;
1439 return 0;
1440 }
1441
1442 /*
1443 * update root item of reloc tree
1444 */
1445 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1446 struct btrfs_root *root)
1447 {
1448 struct btrfs_root *reloc_root;
1449 struct btrfs_root_item *root_item;
1450 int ret;
1451
1452 if (!root->reloc_root)
1453 goto out;
1454
1455 reloc_root = root->reloc_root;
1456 root_item = &reloc_root->root_item;
1457
1458 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1459 btrfs_root_refs(root_item) == 0) {
1460 root->reloc_root = NULL;
1461 __del_reloc_root(reloc_root);
1462 }
1463
1464 if (reloc_root->commit_root != reloc_root->node) {
1465 btrfs_set_root_node(root_item, reloc_root->node);
1466 free_extent_buffer(reloc_root->commit_root);
1467 reloc_root->commit_root = btrfs_root_node(reloc_root);
1468 }
1469
1470 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1471 &reloc_root->root_key, root_item);
1472 BUG_ON(ret);
1473
1474 out:
1475 return 0;
1476 }
1477
1478 /*
1479 * helper to find first cached inode with inode number >= objectid
1480 * in a subvolume
1481 */
1482 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1483 {
1484 struct rb_node *node;
1485 struct rb_node *prev;
1486 struct btrfs_inode *entry;
1487 struct inode *inode;
1488
1489 spin_lock(&root->inode_lock);
1490 again:
1491 node = root->inode_tree.rb_node;
1492 prev = NULL;
1493 while (node) {
1494 prev = node;
1495 entry = rb_entry(node, struct btrfs_inode, rb_node);
1496
1497 if (objectid < btrfs_ino(&entry->vfs_inode))
1498 node = node->rb_left;
1499 else if (objectid > btrfs_ino(&entry->vfs_inode))
1500 node = node->rb_right;
1501 else
1502 break;
1503 }
1504 if (!node) {
1505 while (prev) {
1506 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1507 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1508 node = prev;
1509 break;
1510 }
1511 prev = rb_next(prev);
1512 }
1513 }
1514 while (node) {
1515 entry = rb_entry(node, struct btrfs_inode, rb_node);
1516 inode = igrab(&entry->vfs_inode);
1517 if (inode) {
1518 spin_unlock(&root->inode_lock);
1519 return inode;
1520 }
1521
1522 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1523 if (cond_resched_lock(&root->inode_lock))
1524 goto again;
1525
1526 node = rb_next(node);
1527 }
1528 spin_unlock(&root->inode_lock);
1529 return NULL;
1530 }
1531
1532 static int in_block_group(u64 bytenr,
1533 struct btrfs_block_group_cache *block_group)
1534 {
1535 if (bytenr >= block_group->key.objectid &&
1536 bytenr < block_group->key.objectid + block_group->key.offset)
1537 return 1;
1538 return 0;
1539 }
1540
1541 /*
1542 * get new location of data
1543 */
1544 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1545 u64 bytenr, u64 num_bytes)
1546 {
1547 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1548 struct btrfs_path *path;
1549 struct btrfs_file_extent_item *fi;
1550 struct extent_buffer *leaf;
1551 int ret;
1552
1553 path = btrfs_alloc_path();
1554 if (!path)
1555 return -ENOMEM;
1556
1557 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1558 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1559 bytenr, 0);
1560 if (ret < 0)
1561 goto out;
1562 if (ret > 0) {
1563 ret = -ENOENT;
1564 goto out;
1565 }
1566
1567 leaf = path->nodes[0];
1568 fi = btrfs_item_ptr(leaf, path->slots[0],
1569 struct btrfs_file_extent_item);
1570
1571 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1572 btrfs_file_extent_compression(leaf, fi) ||
1573 btrfs_file_extent_encryption(leaf, fi) ||
1574 btrfs_file_extent_other_encoding(leaf, fi));
1575
1576 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1577 ret = -EINVAL;
1578 goto out;
1579 }
1580
1581 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1582 ret = 0;
1583 out:
1584 btrfs_free_path(path);
1585 return ret;
1586 }
1587
1588 /*
1589 * update file extent items in the tree leaf to point to
1590 * the new locations.
1591 */
1592 static noinline_for_stack
1593 int replace_file_extents(struct btrfs_trans_handle *trans,
1594 struct reloc_control *rc,
1595 struct btrfs_root *root,
1596 struct extent_buffer *leaf)
1597 {
1598 struct btrfs_key key;
1599 struct btrfs_file_extent_item *fi;
1600 struct inode *inode = NULL;
1601 u64 parent;
1602 u64 bytenr;
1603 u64 new_bytenr = 0;
1604 u64 num_bytes;
1605 u64 end;
1606 u32 nritems;
1607 u32 i;
1608 int ret = 0;
1609 int first = 1;
1610 int dirty = 0;
1611
1612 if (rc->stage != UPDATE_DATA_PTRS)
1613 return 0;
1614
1615 /* reloc trees always use full backref */
1616 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1617 parent = leaf->start;
1618 else
1619 parent = 0;
1620
1621 nritems = btrfs_header_nritems(leaf);
1622 for (i = 0; i < nritems; i++) {
1623 cond_resched();
1624 btrfs_item_key_to_cpu(leaf, &key, i);
1625 if (key.type != BTRFS_EXTENT_DATA_KEY)
1626 continue;
1627 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1628 if (btrfs_file_extent_type(leaf, fi) ==
1629 BTRFS_FILE_EXTENT_INLINE)
1630 continue;
1631 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1632 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1633 if (bytenr == 0)
1634 continue;
1635 if (!in_block_group(bytenr, rc->block_group))
1636 continue;
1637
1638 /*
1639 * if we are modifying block in fs tree, wait for readpage
1640 * to complete and drop the extent cache
1641 */
1642 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1643 if (first) {
1644 inode = find_next_inode(root, key.objectid);
1645 first = 0;
1646 } else if (inode && btrfs_ino(inode) < key.objectid) {
1647 btrfs_add_delayed_iput(inode);
1648 inode = find_next_inode(root, key.objectid);
1649 }
1650 if (inode && btrfs_ino(inode) == key.objectid) {
1651 end = key.offset +
1652 btrfs_file_extent_num_bytes(leaf, fi);
1653 WARN_ON(!IS_ALIGNED(key.offset,
1654 root->sectorsize));
1655 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1656 end--;
1657 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1658 key.offset, end);
1659 if (!ret)
1660 continue;
1661
1662 btrfs_drop_extent_cache(inode, key.offset, end,
1663 1);
1664 unlock_extent(&BTRFS_I(inode)->io_tree,
1665 key.offset, end);
1666 }
1667 }
1668
1669 ret = get_new_location(rc->data_inode, &new_bytenr,
1670 bytenr, num_bytes);
1671 if (ret) {
1672 /*
1673 * Don't have to abort since we've not changed anything
1674 * in the file extent yet.
1675 */
1676 break;
1677 }
1678
1679 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1680 dirty = 1;
1681
1682 key.offset -= btrfs_file_extent_offset(leaf, fi);
1683 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1684 num_bytes, parent,
1685 btrfs_header_owner(leaf),
1686 key.objectid, key.offset, 1);
1687 if (ret) {
1688 btrfs_abort_transaction(trans, root, ret);
1689 break;
1690 }
1691
1692 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1693 parent, btrfs_header_owner(leaf),
1694 key.objectid, key.offset, 1);
1695 if (ret) {
1696 btrfs_abort_transaction(trans, root, ret);
1697 break;
1698 }
1699 }
1700 if (dirty)
1701 btrfs_mark_buffer_dirty(leaf);
1702 if (inode)
1703 btrfs_add_delayed_iput(inode);
1704 return ret;
1705 }
1706
1707 static noinline_for_stack
1708 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1709 struct btrfs_path *path, int level)
1710 {
1711 struct btrfs_disk_key key1;
1712 struct btrfs_disk_key key2;
1713 btrfs_node_key(eb, &key1, slot);
1714 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1715 return memcmp(&key1, &key2, sizeof(key1));
1716 }
1717
1718 /*
1719 * try to replace tree blocks in fs tree with the new blocks
1720 * in reloc tree. tree blocks haven't been modified since the
1721 * reloc tree was create can be replaced.
1722 *
1723 * if a block was replaced, level of the block + 1 is returned.
1724 * if no block got replaced, 0 is returned. if there are other
1725 * errors, a negative error number is returned.
1726 */
1727 static noinline_for_stack
1728 int replace_path(struct btrfs_trans_handle *trans,
1729 struct btrfs_root *dest, struct btrfs_root *src,
1730 struct btrfs_path *path, struct btrfs_key *next_key,
1731 int lowest_level, int max_level)
1732 {
1733 struct extent_buffer *eb;
1734 struct extent_buffer *parent;
1735 struct btrfs_key key;
1736 u64 old_bytenr;
1737 u64 new_bytenr;
1738 u64 old_ptr_gen;
1739 u64 new_ptr_gen;
1740 u64 last_snapshot;
1741 u32 blocksize;
1742 int cow = 0;
1743 int level;
1744 int ret;
1745 int slot;
1746
1747 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1748 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1749
1750 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1751 again:
1752 slot = path->slots[lowest_level];
1753 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1754
1755 eb = btrfs_lock_root_node(dest);
1756 btrfs_set_lock_blocking(eb);
1757 level = btrfs_header_level(eb);
1758
1759 if (level < lowest_level) {
1760 btrfs_tree_unlock(eb);
1761 free_extent_buffer(eb);
1762 return 0;
1763 }
1764
1765 if (cow) {
1766 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1767 BUG_ON(ret);
1768 }
1769 btrfs_set_lock_blocking(eb);
1770
1771 if (next_key) {
1772 next_key->objectid = (u64)-1;
1773 next_key->type = (u8)-1;
1774 next_key->offset = (u64)-1;
1775 }
1776
1777 parent = eb;
1778 while (1) {
1779 level = btrfs_header_level(parent);
1780 BUG_ON(level < lowest_level);
1781
1782 ret = btrfs_bin_search(parent, &key, level, &slot);
1783 if (ret && slot > 0)
1784 slot--;
1785
1786 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1787 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1788
1789 old_bytenr = btrfs_node_blockptr(parent, slot);
1790 blocksize = btrfs_level_size(dest, level - 1);
1791 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1792
1793 if (level <= max_level) {
1794 eb = path->nodes[level];
1795 new_bytenr = btrfs_node_blockptr(eb,
1796 path->slots[level]);
1797 new_ptr_gen = btrfs_node_ptr_generation(eb,
1798 path->slots[level]);
1799 } else {
1800 new_bytenr = 0;
1801 new_ptr_gen = 0;
1802 }
1803
1804 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1805 ret = level;
1806 break;
1807 }
1808
1809 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1810 memcmp_node_keys(parent, slot, path, level)) {
1811 if (level <= lowest_level) {
1812 ret = 0;
1813 break;
1814 }
1815
1816 eb = read_tree_block(dest, old_bytenr, blocksize,
1817 old_ptr_gen);
1818 if (!eb || !extent_buffer_uptodate(eb)) {
1819 ret = (!eb) ? -ENOMEM : -EIO;
1820 free_extent_buffer(eb);
1821 break;
1822 }
1823 btrfs_tree_lock(eb);
1824 if (cow) {
1825 ret = btrfs_cow_block(trans, dest, eb, parent,
1826 slot, &eb);
1827 BUG_ON(ret);
1828 }
1829 btrfs_set_lock_blocking(eb);
1830
1831 btrfs_tree_unlock(parent);
1832 free_extent_buffer(parent);
1833
1834 parent = eb;
1835 continue;
1836 }
1837
1838 if (!cow) {
1839 btrfs_tree_unlock(parent);
1840 free_extent_buffer(parent);
1841 cow = 1;
1842 goto again;
1843 }
1844
1845 btrfs_node_key_to_cpu(path->nodes[level], &key,
1846 path->slots[level]);
1847 btrfs_release_path(path);
1848
1849 path->lowest_level = level;
1850 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1851 path->lowest_level = 0;
1852 BUG_ON(ret);
1853
1854 /*
1855 * swap blocks in fs tree and reloc tree.
1856 */
1857 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1858 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1859 btrfs_mark_buffer_dirty(parent);
1860
1861 btrfs_set_node_blockptr(path->nodes[level],
1862 path->slots[level], old_bytenr);
1863 btrfs_set_node_ptr_generation(path->nodes[level],
1864 path->slots[level], old_ptr_gen);
1865 btrfs_mark_buffer_dirty(path->nodes[level]);
1866
1867 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1868 path->nodes[level]->start,
1869 src->root_key.objectid, level - 1, 0,
1870 1);
1871 BUG_ON(ret);
1872 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1873 0, dest->root_key.objectid, level - 1,
1874 0, 1);
1875 BUG_ON(ret);
1876
1877 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1878 path->nodes[level]->start,
1879 src->root_key.objectid, level - 1, 0,
1880 1);
1881 BUG_ON(ret);
1882
1883 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1884 0, dest->root_key.objectid, level - 1,
1885 0, 1);
1886 BUG_ON(ret);
1887
1888 btrfs_unlock_up_safe(path, 0);
1889
1890 ret = level;
1891 break;
1892 }
1893 btrfs_tree_unlock(parent);
1894 free_extent_buffer(parent);
1895 return ret;
1896 }
1897
1898 /*
1899 * helper to find next relocated block in reloc tree
1900 */
1901 static noinline_for_stack
1902 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1903 int *level)
1904 {
1905 struct extent_buffer *eb;
1906 int i;
1907 u64 last_snapshot;
1908 u32 nritems;
1909
1910 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1911
1912 for (i = 0; i < *level; i++) {
1913 free_extent_buffer(path->nodes[i]);
1914 path->nodes[i] = NULL;
1915 }
1916
1917 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1918 eb = path->nodes[i];
1919 nritems = btrfs_header_nritems(eb);
1920 while (path->slots[i] + 1 < nritems) {
1921 path->slots[i]++;
1922 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1923 last_snapshot)
1924 continue;
1925
1926 *level = i;
1927 return 0;
1928 }
1929 free_extent_buffer(path->nodes[i]);
1930 path->nodes[i] = NULL;
1931 }
1932 return 1;
1933 }
1934
1935 /*
1936 * walk down reloc tree to find relocated block of lowest level
1937 */
1938 static noinline_for_stack
1939 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1940 int *level)
1941 {
1942 struct extent_buffer *eb = NULL;
1943 int i;
1944 u64 bytenr;
1945 u64 ptr_gen = 0;
1946 u64 last_snapshot;
1947 u32 blocksize;
1948 u32 nritems;
1949
1950 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1951
1952 for (i = *level; i > 0; i--) {
1953 eb = path->nodes[i];
1954 nritems = btrfs_header_nritems(eb);
1955 while (path->slots[i] < nritems) {
1956 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1957 if (ptr_gen > last_snapshot)
1958 break;
1959 path->slots[i]++;
1960 }
1961 if (path->slots[i] >= nritems) {
1962 if (i == *level)
1963 break;
1964 *level = i + 1;
1965 return 0;
1966 }
1967 if (i == 1) {
1968 *level = i;
1969 return 0;
1970 }
1971
1972 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1973 blocksize = btrfs_level_size(root, i - 1);
1974 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1975 if (!eb || !extent_buffer_uptodate(eb)) {
1976 free_extent_buffer(eb);
1977 return -EIO;
1978 }
1979 BUG_ON(btrfs_header_level(eb) != i - 1);
1980 path->nodes[i - 1] = eb;
1981 path->slots[i - 1] = 0;
1982 }
1983 return 1;
1984 }
1985
1986 /*
1987 * invalidate extent cache for file extents whose key in range of
1988 * [min_key, max_key)
1989 */
1990 static int invalidate_extent_cache(struct btrfs_root *root,
1991 struct btrfs_key *min_key,
1992 struct btrfs_key *max_key)
1993 {
1994 struct inode *inode = NULL;
1995 u64 objectid;
1996 u64 start, end;
1997 u64 ino;
1998
1999 objectid = min_key->objectid;
2000 while (1) {
2001 cond_resched();
2002 iput(inode);
2003
2004 if (objectid > max_key->objectid)
2005 break;
2006
2007 inode = find_next_inode(root, objectid);
2008 if (!inode)
2009 break;
2010 ino = btrfs_ino(inode);
2011
2012 if (ino > max_key->objectid) {
2013 iput(inode);
2014 break;
2015 }
2016
2017 objectid = ino + 1;
2018 if (!S_ISREG(inode->i_mode))
2019 continue;
2020
2021 if (unlikely(min_key->objectid == ino)) {
2022 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2023 continue;
2024 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2025 start = 0;
2026 else {
2027 start = min_key->offset;
2028 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2029 }
2030 } else {
2031 start = 0;
2032 }
2033
2034 if (unlikely(max_key->objectid == ino)) {
2035 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2036 continue;
2037 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2038 end = (u64)-1;
2039 } else {
2040 if (max_key->offset == 0)
2041 continue;
2042 end = max_key->offset;
2043 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2044 end--;
2045 }
2046 } else {
2047 end = (u64)-1;
2048 }
2049
2050 /* the lock_extent waits for readpage to complete */
2051 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2052 btrfs_drop_extent_cache(inode, start, end, 1);
2053 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2054 }
2055 return 0;
2056 }
2057
2058 static int find_next_key(struct btrfs_path *path, int level,
2059 struct btrfs_key *key)
2060
2061 {
2062 while (level < BTRFS_MAX_LEVEL) {
2063 if (!path->nodes[level])
2064 break;
2065 if (path->slots[level] + 1 <
2066 btrfs_header_nritems(path->nodes[level])) {
2067 btrfs_node_key_to_cpu(path->nodes[level], key,
2068 path->slots[level] + 1);
2069 return 0;
2070 }
2071 level++;
2072 }
2073 return 1;
2074 }
2075
2076 /*
2077 * merge the relocated tree blocks in reloc tree with corresponding
2078 * fs tree.
2079 */
2080 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2081 struct btrfs_root *root)
2082 {
2083 LIST_HEAD(inode_list);
2084 struct btrfs_key key;
2085 struct btrfs_key next_key;
2086 struct btrfs_trans_handle *trans = NULL;
2087 struct btrfs_root *reloc_root;
2088 struct btrfs_root_item *root_item;
2089 struct btrfs_path *path;
2090 struct extent_buffer *leaf;
2091 int level;
2092 int max_level;
2093 int replaced = 0;
2094 int ret;
2095 int err = 0;
2096 u32 min_reserved;
2097
2098 path = btrfs_alloc_path();
2099 if (!path)
2100 return -ENOMEM;
2101 path->reada = 1;
2102
2103 reloc_root = root->reloc_root;
2104 root_item = &reloc_root->root_item;
2105
2106 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2107 level = btrfs_root_level(root_item);
2108 extent_buffer_get(reloc_root->node);
2109 path->nodes[level] = reloc_root->node;
2110 path->slots[level] = 0;
2111 } else {
2112 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2113
2114 level = root_item->drop_level;
2115 BUG_ON(level == 0);
2116 path->lowest_level = level;
2117 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2118 path->lowest_level = 0;
2119 if (ret < 0) {
2120 btrfs_free_path(path);
2121 return ret;
2122 }
2123
2124 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2125 path->slots[level]);
2126 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2127
2128 btrfs_unlock_up_safe(path, 0);
2129 }
2130
2131 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2132 memset(&next_key, 0, sizeof(next_key));
2133
2134 while (1) {
2135 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2136 BTRFS_RESERVE_FLUSH_ALL);
2137 if (ret) {
2138 err = ret;
2139 goto out;
2140 }
2141 trans = btrfs_start_transaction(root, 0);
2142 if (IS_ERR(trans)) {
2143 err = PTR_ERR(trans);
2144 trans = NULL;
2145 goto out;
2146 }
2147 trans->block_rsv = rc->block_rsv;
2148
2149 replaced = 0;
2150 max_level = level;
2151
2152 ret = walk_down_reloc_tree(reloc_root, path, &level);
2153 if (ret < 0) {
2154 err = ret;
2155 goto out;
2156 }
2157 if (ret > 0)
2158 break;
2159
2160 if (!find_next_key(path, level, &key) &&
2161 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2162 ret = 0;
2163 } else {
2164 ret = replace_path(trans, root, reloc_root, path,
2165 &next_key, level, max_level);
2166 }
2167 if (ret < 0) {
2168 err = ret;
2169 goto out;
2170 }
2171
2172 if (ret > 0) {
2173 level = ret;
2174 btrfs_node_key_to_cpu(path->nodes[level], &key,
2175 path->slots[level]);
2176 replaced = 1;
2177 }
2178
2179 ret = walk_up_reloc_tree(reloc_root, path, &level);
2180 if (ret > 0)
2181 break;
2182
2183 BUG_ON(level == 0);
2184 /*
2185 * save the merging progress in the drop_progress.
2186 * this is OK since root refs == 1 in this case.
2187 */
2188 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2189 path->slots[level]);
2190 root_item->drop_level = level;
2191
2192 btrfs_end_transaction_throttle(trans, root);
2193 trans = NULL;
2194
2195 btrfs_btree_balance_dirty(root);
2196
2197 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2198 invalidate_extent_cache(root, &key, &next_key);
2199 }
2200
2201 /*
2202 * handle the case only one block in the fs tree need to be
2203 * relocated and the block is tree root.
2204 */
2205 leaf = btrfs_lock_root_node(root);
2206 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2207 btrfs_tree_unlock(leaf);
2208 free_extent_buffer(leaf);
2209 if (ret < 0)
2210 err = ret;
2211 out:
2212 btrfs_free_path(path);
2213
2214 if (err == 0) {
2215 memset(&root_item->drop_progress, 0,
2216 sizeof(root_item->drop_progress));
2217 root_item->drop_level = 0;
2218 btrfs_set_root_refs(root_item, 0);
2219 btrfs_update_reloc_root(trans, root);
2220 }
2221
2222 if (trans)
2223 btrfs_end_transaction_throttle(trans, root);
2224
2225 btrfs_btree_balance_dirty(root);
2226
2227 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2228 invalidate_extent_cache(root, &key, &next_key);
2229
2230 return err;
2231 }
2232
2233 static noinline_for_stack
2234 int prepare_to_merge(struct reloc_control *rc, int err)
2235 {
2236 struct btrfs_root *root = rc->extent_root;
2237 struct btrfs_root *reloc_root;
2238 struct btrfs_trans_handle *trans;
2239 LIST_HEAD(reloc_roots);
2240 u64 num_bytes = 0;
2241 int ret;
2242
2243 mutex_lock(&root->fs_info->reloc_mutex);
2244 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2245 rc->merging_rsv_size += rc->nodes_relocated * 2;
2246 mutex_unlock(&root->fs_info->reloc_mutex);
2247
2248 again:
2249 if (!err) {
2250 num_bytes = rc->merging_rsv_size;
2251 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2252 BTRFS_RESERVE_FLUSH_ALL);
2253 if (ret)
2254 err = ret;
2255 }
2256
2257 trans = btrfs_join_transaction(rc->extent_root);
2258 if (IS_ERR(trans)) {
2259 if (!err)
2260 btrfs_block_rsv_release(rc->extent_root,
2261 rc->block_rsv, num_bytes);
2262 return PTR_ERR(trans);
2263 }
2264
2265 if (!err) {
2266 if (num_bytes != rc->merging_rsv_size) {
2267 btrfs_end_transaction(trans, rc->extent_root);
2268 btrfs_block_rsv_release(rc->extent_root,
2269 rc->block_rsv, num_bytes);
2270 goto again;
2271 }
2272 }
2273
2274 rc->merge_reloc_tree = 1;
2275
2276 while (!list_empty(&rc->reloc_roots)) {
2277 reloc_root = list_entry(rc->reloc_roots.next,
2278 struct btrfs_root, root_list);
2279 list_del_init(&reloc_root->root_list);
2280
2281 root = read_fs_root(reloc_root->fs_info,
2282 reloc_root->root_key.offset);
2283 BUG_ON(IS_ERR(root));
2284 BUG_ON(root->reloc_root != reloc_root);
2285
2286 /*
2287 * set reference count to 1, so btrfs_recover_relocation
2288 * knows it should resumes merging
2289 */
2290 if (!err)
2291 btrfs_set_root_refs(&reloc_root->root_item, 1);
2292 btrfs_update_reloc_root(trans, root);
2293
2294 list_add(&reloc_root->root_list, &reloc_roots);
2295 }
2296
2297 list_splice(&reloc_roots, &rc->reloc_roots);
2298
2299 if (!err)
2300 btrfs_commit_transaction(trans, rc->extent_root);
2301 else
2302 btrfs_end_transaction(trans, rc->extent_root);
2303 return err;
2304 }
2305
2306 static noinline_for_stack
2307 void free_reloc_roots(struct list_head *list)
2308 {
2309 struct btrfs_root *reloc_root;
2310
2311 while (!list_empty(list)) {
2312 reloc_root = list_entry(list->next, struct btrfs_root,
2313 root_list);
2314 __del_reloc_root(reloc_root);
2315 }
2316 }
2317
2318 static noinline_for_stack
2319 int merge_reloc_roots(struct reloc_control *rc)
2320 {
2321 struct btrfs_root *root;
2322 struct btrfs_root *reloc_root;
2323 u64 last_snap;
2324 u64 otransid;
2325 u64 objectid;
2326 LIST_HEAD(reloc_roots);
2327 int found = 0;
2328 int ret = 0;
2329 again:
2330 root = rc->extent_root;
2331
2332 /*
2333 * this serializes us with btrfs_record_root_in_transaction,
2334 * we have to make sure nobody is in the middle of
2335 * adding their roots to the list while we are
2336 * doing this splice
2337 */
2338 mutex_lock(&root->fs_info->reloc_mutex);
2339 list_splice_init(&rc->reloc_roots, &reloc_roots);
2340 mutex_unlock(&root->fs_info->reloc_mutex);
2341
2342 while (!list_empty(&reloc_roots)) {
2343 found = 1;
2344 reloc_root = list_entry(reloc_roots.next,
2345 struct btrfs_root, root_list);
2346
2347 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2348 root = read_fs_root(reloc_root->fs_info,
2349 reloc_root->root_key.offset);
2350 BUG_ON(IS_ERR(root));
2351 BUG_ON(root->reloc_root != reloc_root);
2352
2353 ret = merge_reloc_root(rc, root);
2354 if (ret) {
2355 if (list_empty(&reloc_root->root_list))
2356 list_add_tail(&reloc_root->root_list,
2357 &reloc_roots);
2358 goto out;
2359 }
2360 } else {
2361 list_del_init(&reloc_root->root_list);
2362 }
2363
2364 /*
2365 * we keep the old last snapshod transid in rtranid when we
2366 * created the relocation tree.
2367 */
2368 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2369 otransid = btrfs_root_otransid(&reloc_root->root_item);
2370 objectid = reloc_root->root_key.offset;
2371
2372 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2373 if (ret < 0) {
2374 if (list_empty(&reloc_root->root_list))
2375 list_add_tail(&reloc_root->root_list,
2376 &reloc_roots);
2377 goto out;
2378 }
2379 }
2380
2381 if (found) {
2382 found = 0;
2383 goto again;
2384 }
2385 out:
2386 if (ret) {
2387 btrfs_std_error(root->fs_info, ret);
2388 if (!list_empty(&reloc_roots))
2389 free_reloc_roots(&reloc_roots);
2390
2391 /* new reloc root may be added */
2392 mutex_lock(&root->fs_info->reloc_mutex);
2393 list_splice_init(&rc->reloc_roots, &reloc_roots);
2394 mutex_unlock(&root->fs_info->reloc_mutex);
2395 if (!list_empty(&reloc_roots))
2396 free_reloc_roots(&reloc_roots);
2397 }
2398
2399 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2400 return ret;
2401 }
2402
2403 static void free_block_list(struct rb_root *blocks)
2404 {
2405 struct tree_block *block;
2406 struct rb_node *rb_node;
2407 while ((rb_node = rb_first(blocks))) {
2408 block = rb_entry(rb_node, struct tree_block, rb_node);
2409 rb_erase(rb_node, blocks);
2410 kfree(block);
2411 }
2412 }
2413
2414 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2415 struct btrfs_root *reloc_root)
2416 {
2417 struct btrfs_root *root;
2418
2419 if (reloc_root->last_trans == trans->transid)
2420 return 0;
2421
2422 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2423 BUG_ON(IS_ERR(root));
2424 BUG_ON(root->reloc_root != reloc_root);
2425
2426 return btrfs_record_root_in_trans(trans, root);
2427 }
2428
2429 static noinline_for_stack
2430 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2431 struct reloc_control *rc,
2432 struct backref_node *node,
2433 struct backref_edge *edges[])
2434 {
2435 struct backref_node *next;
2436 struct btrfs_root *root;
2437 int index = 0;
2438
2439 next = node;
2440 while (1) {
2441 cond_resched();
2442 next = walk_up_backref(next, edges, &index);
2443 root = next->root;
2444 BUG_ON(!root);
2445 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2446
2447 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2448 record_reloc_root_in_trans(trans, root);
2449 break;
2450 }
2451
2452 btrfs_record_root_in_trans(trans, root);
2453 root = root->reloc_root;
2454
2455 if (next->new_bytenr != root->node->start) {
2456 BUG_ON(next->new_bytenr);
2457 BUG_ON(!list_empty(&next->list));
2458 next->new_bytenr = root->node->start;
2459 next->root = root;
2460 list_add_tail(&next->list,
2461 &rc->backref_cache.changed);
2462 __mark_block_processed(rc, next);
2463 break;
2464 }
2465
2466 WARN_ON(1);
2467 root = NULL;
2468 next = walk_down_backref(edges, &index);
2469 if (!next || next->level <= node->level)
2470 break;
2471 }
2472 if (!root)
2473 return NULL;
2474
2475 next = node;
2476 /* setup backref node path for btrfs_reloc_cow_block */
2477 while (1) {
2478 rc->backref_cache.path[next->level] = next;
2479 if (--index < 0)
2480 break;
2481 next = edges[index]->node[UPPER];
2482 }
2483 return root;
2484 }
2485
2486 /*
2487 * select a tree root for relocation. return NULL if the block
2488 * is reference counted. we should use do_relocation() in this
2489 * case. return a tree root pointer if the block isn't reference
2490 * counted. return -ENOENT if the block is root of reloc tree.
2491 */
2492 static noinline_for_stack
2493 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2494 struct backref_node *node)
2495 {
2496 struct backref_node *next;
2497 struct btrfs_root *root;
2498 struct btrfs_root *fs_root = NULL;
2499 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2500 int index = 0;
2501
2502 next = node;
2503 while (1) {
2504 cond_resched();
2505 next = walk_up_backref(next, edges, &index);
2506 root = next->root;
2507 BUG_ON(!root);
2508
2509 /* no other choice for non-references counted tree */
2510 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2511 return root;
2512
2513 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2514 fs_root = root;
2515
2516 if (next != node)
2517 return NULL;
2518
2519 next = walk_down_backref(edges, &index);
2520 if (!next || next->level <= node->level)
2521 break;
2522 }
2523
2524 if (!fs_root)
2525 return ERR_PTR(-ENOENT);
2526 return fs_root;
2527 }
2528
2529 static noinline_for_stack
2530 u64 calcu_metadata_size(struct reloc_control *rc,
2531 struct backref_node *node, int reserve)
2532 {
2533 struct backref_node *next = node;
2534 struct backref_edge *edge;
2535 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2536 u64 num_bytes = 0;
2537 int index = 0;
2538
2539 BUG_ON(reserve && node->processed);
2540
2541 while (next) {
2542 cond_resched();
2543 while (1) {
2544 if (next->processed && (reserve || next != node))
2545 break;
2546
2547 num_bytes += btrfs_level_size(rc->extent_root,
2548 next->level);
2549
2550 if (list_empty(&next->upper))
2551 break;
2552
2553 edge = list_entry(next->upper.next,
2554 struct backref_edge, list[LOWER]);
2555 edges[index++] = edge;
2556 next = edge->node[UPPER];
2557 }
2558 next = walk_down_backref(edges, &index);
2559 }
2560 return num_bytes;
2561 }
2562
2563 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2564 struct reloc_control *rc,
2565 struct backref_node *node)
2566 {
2567 struct btrfs_root *root = rc->extent_root;
2568 u64 num_bytes;
2569 int ret;
2570 u64 tmp;
2571
2572 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2573
2574 trans->block_rsv = rc->block_rsv;
2575 rc->reserved_bytes += num_bytes;
2576 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2577 BTRFS_RESERVE_FLUSH_ALL);
2578 if (ret) {
2579 if (ret == -EAGAIN) {
2580 tmp = rc->extent_root->nodesize *
2581 RELOCATION_RESERVED_NODES;
2582 while (tmp <= rc->reserved_bytes)
2583 tmp <<= 1;
2584 /*
2585 * only one thread can access block_rsv at this point,
2586 * so we don't need hold lock to protect block_rsv.
2587 * we expand more reservation size here to allow enough
2588 * space for relocation and we will return eailer in
2589 * enospc case.
2590 */
2591 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2592 RELOCATION_RESERVED_NODES;
2593 }
2594 return ret;
2595 }
2596
2597 return 0;
2598 }
2599
2600 /*
2601 * relocate a block tree, and then update pointers in upper level
2602 * blocks that reference the block to point to the new location.
2603 *
2604 * if called by link_to_upper, the block has already been relocated.
2605 * in that case this function just updates pointers.
2606 */
2607 static int do_relocation(struct btrfs_trans_handle *trans,
2608 struct reloc_control *rc,
2609 struct backref_node *node,
2610 struct btrfs_key *key,
2611 struct btrfs_path *path, int lowest)
2612 {
2613 struct backref_node *upper;
2614 struct backref_edge *edge;
2615 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2616 struct btrfs_root *root;
2617 struct extent_buffer *eb;
2618 u32 blocksize;
2619 u64 bytenr;
2620 u64 generation;
2621 int slot;
2622 int ret;
2623 int err = 0;
2624
2625 BUG_ON(lowest && node->eb);
2626
2627 path->lowest_level = node->level + 1;
2628 rc->backref_cache.path[node->level] = node;
2629 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2630 cond_resched();
2631
2632 upper = edge->node[UPPER];
2633 root = select_reloc_root(trans, rc, upper, edges);
2634 BUG_ON(!root);
2635
2636 if (upper->eb && !upper->locked) {
2637 if (!lowest) {
2638 ret = btrfs_bin_search(upper->eb, key,
2639 upper->level, &slot);
2640 BUG_ON(ret);
2641 bytenr = btrfs_node_blockptr(upper->eb, slot);
2642 if (node->eb->start == bytenr)
2643 goto next;
2644 }
2645 drop_node_buffer(upper);
2646 }
2647
2648 if (!upper->eb) {
2649 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2650 if (ret < 0) {
2651 err = ret;
2652 break;
2653 }
2654 BUG_ON(ret > 0);
2655
2656 if (!upper->eb) {
2657 upper->eb = path->nodes[upper->level];
2658 path->nodes[upper->level] = NULL;
2659 } else {
2660 BUG_ON(upper->eb != path->nodes[upper->level]);
2661 }
2662
2663 upper->locked = 1;
2664 path->locks[upper->level] = 0;
2665
2666 slot = path->slots[upper->level];
2667 btrfs_release_path(path);
2668 } else {
2669 ret = btrfs_bin_search(upper->eb, key, upper->level,
2670 &slot);
2671 BUG_ON(ret);
2672 }
2673
2674 bytenr = btrfs_node_blockptr(upper->eb, slot);
2675 if (lowest) {
2676 BUG_ON(bytenr != node->bytenr);
2677 } else {
2678 if (node->eb->start == bytenr)
2679 goto next;
2680 }
2681
2682 blocksize = btrfs_level_size(root, node->level);
2683 generation = btrfs_node_ptr_generation(upper->eb, slot);
2684 eb = read_tree_block(root, bytenr, blocksize, generation);
2685 if (!eb || !extent_buffer_uptodate(eb)) {
2686 free_extent_buffer(eb);
2687 err = -EIO;
2688 goto next;
2689 }
2690 btrfs_tree_lock(eb);
2691 btrfs_set_lock_blocking(eb);
2692
2693 if (!node->eb) {
2694 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2695 slot, &eb);
2696 btrfs_tree_unlock(eb);
2697 free_extent_buffer(eb);
2698 if (ret < 0) {
2699 err = ret;
2700 goto next;
2701 }
2702 BUG_ON(node->eb != eb);
2703 } else {
2704 btrfs_set_node_blockptr(upper->eb, slot,
2705 node->eb->start);
2706 btrfs_set_node_ptr_generation(upper->eb, slot,
2707 trans->transid);
2708 btrfs_mark_buffer_dirty(upper->eb);
2709
2710 ret = btrfs_inc_extent_ref(trans, root,
2711 node->eb->start, blocksize,
2712 upper->eb->start,
2713 btrfs_header_owner(upper->eb),
2714 node->level, 0, 1);
2715 BUG_ON(ret);
2716
2717 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2718 BUG_ON(ret);
2719 }
2720 next:
2721 if (!upper->pending)
2722 drop_node_buffer(upper);
2723 else
2724 unlock_node_buffer(upper);
2725 if (err)
2726 break;
2727 }
2728
2729 if (!err && node->pending) {
2730 drop_node_buffer(node);
2731 list_move_tail(&node->list, &rc->backref_cache.changed);
2732 node->pending = 0;
2733 }
2734
2735 path->lowest_level = 0;
2736 BUG_ON(err == -ENOSPC);
2737 return err;
2738 }
2739
2740 static int link_to_upper(struct btrfs_trans_handle *trans,
2741 struct reloc_control *rc,
2742 struct backref_node *node,
2743 struct btrfs_path *path)
2744 {
2745 struct btrfs_key key;
2746
2747 btrfs_node_key_to_cpu(node->eb, &key, 0);
2748 return do_relocation(trans, rc, node, &key, path, 0);
2749 }
2750
2751 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2752 struct reloc_control *rc,
2753 struct btrfs_path *path, int err)
2754 {
2755 LIST_HEAD(list);
2756 struct backref_cache *cache = &rc->backref_cache;
2757 struct backref_node *node;
2758 int level;
2759 int ret;
2760
2761 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2762 while (!list_empty(&cache->pending[level])) {
2763 node = list_entry(cache->pending[level].next,
2764 struct backref_node, list);
2765 list_move_tail(&node->list, &list);
2766 BUG_ON(!node->pending);
2767
2768 if (!err) {
2769 ret = link_to_upper(trans, rc, node, path);
2770 if (ret < 0)
2771 err = ret;
2772 }
2773 }
2774 list_splice_init(&list, &cache->pending[level]);
2775 }
2776 return err;
2777 }
2778
2779 static void mark_block_processed(struct reloc_control *rc,
2780 u64 bytenr, u32 blocksize)
2781 {
2782 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2783 EXTENT_DIRTY, GFP_NOFS);
2784 }
2785
2786 static void __mark_block_processed(struct reloc_control *rc,
2787 struct backref_node *node)
2788 {
2789 u32 blocksize;
2790 if (node->level == 0 ||
2791 in_block_group(node->bytenr, rc->block_group)) {
2792 blocksize = btrfs_level_size(rc->extent_root, node->level);
2793 mark_block_processed(rc, node->bytenr, blocksize);
2794 }
2795 node->processed = 1;
2796 }
2797
2798 /*
2799 * mark a block and all blocks directly/indirectly reference the block
2800 * as processed.
2801 */
2802 static void update_processed_blocks(struct reloc_control *rc,
2803 struct backref_node *node)
2804 {
2805 struct backref_node *next = node;
2806 struct backref_edge *edge;
2807 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2808 int index = 0;
2809
2810 while (next) {
2811 cond_resched();
2812 while (1) {
2813 if (next->processed)
2814 break;
2815
2816 __mark_block_processed(rc, next);
2817
2818 if (list_empty(&next->upper))
2819 break;
2820
2821 edge = list_entry(next->upper.next,
2822 struct backref_edge, list[LOWER]);
2823 edges[index++] = edge;
2824 next = edge->node[UPPER];
2825 }
2826 next = walk_down_backref(edges, &index);
2827 }
2828 }
2829
2830 static int tree_block_processed(u64 bytenr, u32 blocksize,
2831 struct reloc_control *rc)
2832 {
2833 if (test_range_bit(&rc->processed_blocks, bytenr,
2834 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2835 return 1;
2836 return 0;
2837 }
2838
2839 static int get_tree_block_key(struct reloc_control *rc,
2840 struct tree_block *block)
2841 {
2842 struct extent_buffer *eb;
2843
2844 BUG_ON(block->key_ready);
2845 eb = read_tree_block(rc->extent_root, block->bytenr,
2846 block->key.objectid, block->key.offset);
2847 if (!eb || !extent_buffer_uptodate(eb)) {
2848 free_extent_buffer(eb);
2849 return -EIO;
2850 }
2851 WARN_ON(btrfs_header_level(eb) != block->level);
2852 if (block->level == 0)
2853 btrfs_item_key_to_cpu(eb, &block->key, 0);
2854 else
2855 btrfs_node_key_to_cpu(eb, &block->key, 0);
2856 free_extent_buffer(eb);
2857 block->key_ready = 1;
2858 return 0;
2859 }
2860
2861 static int reada_tree_block(struct reloc_control *rc,
2862 struct tree_block *block)
2863 {
2864 BUG_ON(block->key_ready);
2865 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2866 readahead_tree_block(rc->extent_root, block->bytenr,
2867 block->key.objectid,
2868 rc->extent_root->leafsize);
2869 else
2870 readahead_tree_block(rc->extent_root, block->bytenr,
2871 block->key.objectid, block->key.offset);
2872 return 0;
2873 }
2874
2875 /*
2876 * helper function to relocate a tree block
2877 */
2878 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2879 struct reloc_control *rc,
2880 struct backref_node *node,
2881 struct btrfs_key *key,
2882 struct btrfs_path *path)
2883 {
2884 struct btrfs_root *root;
2885 int ret = 0;
2886
2887 if (!node)
2888 return 0;
2889
2890 BUG_ON(node->processed);
2891 root = select_one_root(trans, node);
2892 if (root == ERR_PTR(-ENOENT)) {
2893 update_processed_blocks(rc, node);
2894 goto out;
2895 }
2896
2897 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2898 ret = reserve_metadata_space(trans, rc, node);
2899 if (ret)
2900 goto out;
2901 }
2902
2903 if (root) {
2904 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2905 BUG_ON(node->new_bytenr);
2906 BUG_ON(!list_empty(&node->list));
2907 btrfs_record_root_in_trans(trans, root);
2908 root = root->reloc_root;
2909 node->new_bytenr = root->node->start;
2910 node->root = root;
2911 list_add_tail(&node->list, &rc->backref_cache.changed);
2912 } else {
2913 path->lowest_level = node->level;
2914 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2915 btrfs_release_path(path);
2916 if (ret > 0)
2917 ret = 0;
2918 }
2919 if (!ret)
2920 update_processed_blocks(rc, node);
2921 } else {
2922 ret = do_relocation(trans, rc, node, key, path, 1);
2923 }
2924 out:
2925 if (ret || node->level == 0 || node->cowonly)
2926 remove_backref_node(&rc->backref_cache, node);
2927 return ret;
2928 }
2929
2930 /*
2931 * relocate a list of blocks
2932 */
2933 static noinline_for_stack
2934 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2935 struct reloc_control *rc, struct rb_root *blocks)
2936 {
2937 struct backref_node *node;
2938 struct btrfs_path *path;
2939 struct tree_block *block;
2940 struct rb_node *rb_node;
2941 int ret;
2942 int err = 0;
2943
2944 path = btrfs_alloc_path();
2945 if (!path) {
2946 err = -ENOMEM;
2947 goto out_free_blocks;
2948 }
2949
2950 rb_node = rb_first(blocks);
2951 while (rb_node) {
2952 block = rb_entry(rb_node, struct tree_block, rb_node);
2953 if (!block->key_ready)
2954 reada_tree_block(rc, block);
2955 rb_node = rb_next(rb_node);
2956 }
2957
2958 rb_node = rb_first(blocks);
2959 while (rb_node) {
2960 block = rb_entry(rb_node, struct tree_block, rb_node);
2961 if (!block->key_ready) {
2962 err = get_tree_block_key(rc, block);
2963 if (err)
2964 goto out_free_path;
2965 }
2966 rb_node = rb_next(rb_node);
2967 }
2968
2969 rb_node = rb_first(blocks);
2970 while (rb_node) {
2971 block = rb_entry(rb_node, struct tree_block, rb_node);
2972
2973 node = build_backref_tree(rc, &block->key,
2974 block->level, block->bytenr);
2975 if (IS_ERR(node)) {
2976 err = PTR_ERR(node);
2977 goto out;
2978 }
2979
2980 ret = relocate_tree_block(trans, rc, node, &block->key,
2981 path);
2982 if (ret < 0) {
2983 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2984 err = ret;
2985 goto out;
2986 }
2987 rb_node = rb_next(rb_node);
2988 }
2989 out:
2990 err = finish_pending_nodes(trans, rc, path, err);
2991
2992 out_free_path:
2993 btrfs_free_path(path);
2994 out_free_blocks:
2995 free_block_list(blocks);
2996 return err;
2997 }
2998
2999 static noinline_for_stack
3000 int prealloc_file_extent_cluster(struct inode *inode,
3001 struct file_extent_cluster *cluster)
3002 {
3003 u64 alloc_hint = 0;
3004 u64 start;
3005 u64 end;
3006 u64 offset = BTRFS_I(inode)->index_cnt;
3007 u64 num_bytes;
3008 int nr = 0;
3009 int ret = 0;
3010
3011 BUG_ON(cluster->start != cluster->boundary[0]);
3012 mutex_lock(&inode->i_mutex);
3013
3014 ret = btrfs_check_data_free_space(inode, cluster->end +
3015 1 - cluster->start);
3016 if (ret)
3017 goto out;
3018
3019 while (nr < cluster->nr) {
3020 start = cluster->boundary[nr] - offset;
3021 if (nr + 1 < cluster->nr)
3022 end = cluster->boundary[nr + 1] - 1 - offset;
3023 else
3024 end = cluster->end - offset;
3025
3026 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3027 num_bytes = end + 1 - start;
3028 ret = btrfs_prealloc_file_range(inode, 0, start,
3029 num_bytes, num_bytes,
3030 end + 1, &alloc_hint);
3031 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3032 if (ret)
3033 break;
3034 nr++;
3035 }
3036 btrfs_free_reserved_data_space(inode, cluster->end +
3037 1 - cluster->start);
3038 out:
3039 mutex_unlock(&inode->i_mutex);
3040 return ret;
3041 }
3042
3043 static noinline_for_stack
3044 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3045 u64 block_start)
3046 {
3047 struct btrfs_root *root = BTRFS_I(inode)->root;
3048 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3049 struct extent_map *em;
3050 int ret = 0;
3051
3052 em = alloc_extent_map();
3053 if (!em)
3054 return -ENOMEM;
3055
3056 em->start = start;
3057 em->len = end + 1 - start;
3058 em->block_len = em->len;
3059 em->block_start = block_start;
3060 em->bdev = root->fs_info->fs_devices->latest_bdev;
3061 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3062
3063 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3064 while (1) {
3065 write_lock(&em_tree->lock);
3066 ret = add_extent_mapping(em_tree, em, 0);
3067 write_unlock(&em_tree->lock);
3068 if (ret != -EEXIST) {
3069 free_extent_map(em);
3070 break;
3071 }
3072 btrfs_drop_extent_cache(inode, start, end, 0);
3073 }
3074 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3075 return ret;
3076 }
3077
3078 static int relocate_file_extent_cluster(struct inode *inode,
3079 struct file_extent_cluster *cluster)
3080 {
3081 u64 page_start;
3082 u64 page_end;
3083 u64 offset = BTRFS_I(inode)->index_cnt;
3084 unsigned long index;
3085 unsigned long last_index;
3086 struct page *page;
3087 struct file_ra_state *ra;
3088 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3089 int nr = 0;
3090 int ret = 0;
3091
3092 if (!cluster->nr)
3093 return 0;
3094
3095 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3096 if (!ra)
3097 return -ENOMEM;
3098
3099 ret = prealloc_file_extent_cluster(inode, cluster);
3100 if (ret)
3101 goto out;
3102
3103 file_ra_state_init(ra, inode->i_mapping);
3104
3105 ret = setup_extent_mapping(inode, cluster->start - offset,
3106 cluster->end - offset, cluster->start);
3107 if (ret)
3108 goto out;
3109
3110 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3111 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3112 while (index <= last_index) {
3113 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3114 if (ret)
3115 goto out;
3116
3117 page = find_lock_page(inode->i_mapping, index);
3118 if (!page) {
3119 page_cache_sync_readahead(inode->i_mapping,
3120 ra, NULL, index,
3121 last_index + 1 - index);
3122 page = find_or_create_page(inode->i_mapping, index,
3123 mask);
3124 if (!page) {
3125 btrfs_delalloc_release_metadata(inode,
3126 PAGE_CACHE_SIZE);
3127 ret = -ENOMEM;
3128 goto out;
3129 }
3130 }
3131
3132 if (PageReadahead(page)) {
3133 page_cache_async_readahead(inode->i_mapping,
3134 ra, NULL, page, index,
3135 last_index + 1 - index);
3136 }
3137
3138 if (!PageUptodate(page)) {
3139 btrfs_readpage(NULL, page);
3140 lock_page(page);
3141 if (!PageUptodate(page)) {
3142 unlock_page(page);
3143 page_cache_release(page);
3144 btrfs_delalloc_release_metadata(inode,
3145 PAGE_CACHE_SIZE);
3146 ret = -EIO;
3147 goto out;
3148 }
3149 }
3150
3151 page_start = page_offset(page);
3152 page_end = page_start + PAGE_CACHE_SIZE - 1;
3153
3154 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3155
3156 set_page_extent_mapped(page);
3157
3158 if (nr < cluster->nr &&
3159 page_start + offset == cluster->boundary[nr]) {
3160 set_extent_bits(&BTRFS_I(inode)->io_tree,
3161 page_start, page_end,
3162 EXTENT_BOUNDARY, GFP_NOFS);
3163 nr++;
3164 }
3165
3166 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3167 set_page_dirty(page);
3168
3169 unlock_extent(&BTRFS_I(inode)->io_tree,
3170 page_start, page_end);
3171 unlock_page(page);
3172 page_cache_release(page);
3173
3174 index++;
3175 balance_dirty_pages_ratelimited(inode->i_mapping);
3176 btrfs_throttle(BTRFS_I(inode)->root);
3177 }
3178 WARN_ON(nr != cluster->nr);
3179 out:
3180 kfree(ra);
3181 return ret;
3182 }
3183
3184 static noinline_for_stack
3185 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3186 struct file_extent_cluster *cluster)
3187 {
3188 int ret;
3189
3190 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3191 ret = relocate_file_extent_cluster(inode, cluster);
3192 if (ret)
3193 return ret;
3194 cluster->nr = 0;
3195 }
3196
3197 if (!cluster->nr)
3198 cluster->start = extent_key->objectid;
3199 else
3200 BUG_ON(cluster->nr >= MAX_EXTENTS);
3201 cluster->end = extent_key->objectid + extent_key->offset - 1;
3202 cluster->boundary[cluster->nr] = extent_key->objectid;
3203 cluster->nr++;
3204
3205 if (cluster->nr >= MAX_EXTENTS) {
3206 ret = relocate_file_extent_cluster(inode, cluster);
3207 if (ret)
3208 return ret;
3209 cluster->nr = 0;
3210 }
3211 return 0;
3212 }
3213
3214 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3215 static int get_ref_objectid_v0(struct reloc_control *rc,
3216 struct btrfs_path *path,
3217 struct btrfs_key *extent_key,
3218 u64 *ref_objectid, int *path_change)
3219 {
3220 struct btrfs_key key;
3221 struct extent_buffer *leaf;
3222 struct btrfs_extent_ref_v0 *ref0;
3223 int ret;
3224 int slot;
3225
3226 leaf = path->nodes[0];
3227 slot = path->slots[0];
3228 while (1) {
3229 if (slot >= btrfs_header_nritems(leaf)) {
3230 ret = btrfs_next_leaf(rc->extent_root, path);
3231 if (ret < 0)
3232 return ret;
3233 BUG_ON(ret > 0);
3234 leaf = path->nodes[0];
3235 slot = path->slots[0];
3236 if (path_change)
3237 *path_change = 1;
3238 }
3239 btrfs_item_key_to_cpu(leaf, &key, slot);
3240 if (key.objectid != extent_key->objectid)
3241 return -ENOENT;
3242
3243 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3244 slot++;
3245 continue;
3246 }
3247 ref0 = btrfs_item_ptr(leaf, slot,
3248 struct btrfs_extent_ref_v0);
3249 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3250 break;
3251 }
3252 return 0;
3253 }
3254 #endif
3255
3256 /*
3257 * helper to add a tree block to the list.
3258 * the major work is getting the generation and level of the block
3259 */
3260 static int add_tree_block(struct reloc_control *rc,
3261 struct btrfs_key *extent_key,
3262 struct btrfs_path *path,
3263 struct rb_root *blocks)
3264 {
3265 struct extent_buffer *eb;
3266 struct btrfs_extent_item *ei;
3267 struct btrfs_tree_block_info *bi;
3268 struct tree_block *block;
3269 struct rb_node *rb_node;
3270 u32 item_size;
3271 int level = -1;
3272 u64 generation;
3273
3274 eb = path->nodes[0];
3275 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3276
3277 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3278 item_size >= sizeof(*ei) + sizeof(*bi)) {
3279 ei = btrfs_item_ptr(eb, path->slots[0],
3280 struct btrfs_extent_item);
3281 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3282 bi = (struct btrfs_tree_block_info *)(ei + 1);
3283 level = btrfs_tree_block_level(eb, bi);
3284 } else {
3285 level = (int)extent_key->offset;
3286 }
3287 generation = btrfs_extent_generation(eb, ei);
3288 } else {
3289 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3290 u64 ref_owner;
3291 int ret;
3292
3293 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3294 ret = get_ref_objectid_v0(rc, path, extent_key,
3295 &ref_owner, NULL);
3296 if (ret < 0)
3297 return ret;
3298 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3299 level = (int)ref_owner;
3300 /* FIXME: get real generation */
3301 generation = 0;
3302 #else
3303 BUG();
3304 #endif
3305 }
3306
3307 btrfs_release_path(path);
3308
3309 BUG_ON(level == -1);
3310
3311 block = kmalloc(sizeof(*block), GFP_NOFS);
3312 if (!block)
3313 return -ENOMEM;
3314
3315 block->bytenr = extent_key->objectid;
3316 block->key.objectid = rc->extent_root->leafsize;
3317 block->key.offset = generation;
3318 block->level = level;
3319 block->key_ready = 0;
3320
3321 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3322 if (rb_node)
3323 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3324
3325 return 0;
3326 }
3327
3328 /*
3329 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3330 */
3331 static int __add_tree_block(struct reloc_control *rc,
3332 u64 bytenr, u32 blocksize,
3333 struct rb_root *blocks)
3334 {
3335 struct btrfs_path *path;
3336 struct btrfs_key key;
3337 int ret;
3338 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3339 SKINNY_METADATA);
3340
3341 if (tree_block_processed(bytenr, blocksize, rc))
3342 return 0;
3343
3344 if (tree_search(blocks, bytenr))
3345 return 0;
3346
3347 path = btrfs_alloc_path();
3348 if (!path)
3349 return -ENOMEM;
3350 again:
3351 key.objectid = bytenr;
3352 if (skinny) {
3353 key.type = BTRFS_METADATA_ITEM_KEY;
3354 key.offset = (u64)-1;
3355 } else {
3356 key.type = BTRFS_EXTENT_ITEM_KEY;
3357 key.offset = blocksize;
3358 }
3359
3360 path->search_commit_root = 1;
3361 path->skip_locking = 1;
3362 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3363 if (ret < 0)
3364 goto out;
3365
3366 if (ret > 0 && skinny) {
3367 if (path->slots[0]) {
3368 path->slots[0]--;
3369 btrfs_item_key_to_cpu(path->nodes[0], &key,
3370 path->slots[0]);
3371 if (key.objectid == bytenr &&
3372 (key.type == BTRFS_METADATA_ITEM_KEY ||
3373 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3374 key.offset == blocksize)))
3375 ret = 0;
3376 }
3377
3378 if (ret) {
3379 skinny = false;
3380 btrfs_release_path(path);
3381 goto again;
3382 }
3383 }
3384 BUG_ON(ret);
3385
3386 ret = add_tree_block(rc, &key, path, blocks);
3387 out:
3388 btrfs_free_path(path);
3389 return ret;
3390 }
3391
3392 /*
3393 * helper to check if the block use full backrefs for pointers in it
3394 */
3395 static int block_use_full_backref(struct reloc_control *rc,
3396 struct extent_buffer *eb)
3397 {
3398 u64 flags;
3399 int ret;
3400
3401 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3402 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3403 return 1;
3404
3405 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3406 eb->start, btrfs_header_level(eb), 1,
3407 NULL, &flags);
3408 BUG_ON(ret);
3409
3410 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3411 ret = 1;
3412 else
3413 ret = 0;
3414 return ret;
3415 }
3416
3417 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3418 struct inode *inode, u64 ino)
3419 {
3420 struct btrfs_key key;
3421 struct btrfs_root *root = fs_info->tree_root;
3422 struct btrfs_trans_handle *trans;
3423 int ret = 0;
3424
3425 if (inode)
3426 goto truncate;
3427
3428 key.objectid = ino;
3429 key.type = BTRFS_INODE_ITEM_KEY;
3430 key.offset = 0;
3431
3432 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3433 if (IS_ERR(inode) || is_bad_inode(inode)) {
3434 if (!IS_ERR(inode))
3435 iput(inode);
3436 return -ENOENT;
3437 }
3438
3439 truncate:
3440 ret = btrfs_check_trunc_cache_free_space(root,
3441 &fs_info->global_block_rsv);
3442 if (ret)
3443 goto out;
3444
3445 trans = btrfs_join_transaction(root);
3446 if (IS_ERR(trans)) {
3447 ret = PTR_ERR(trans);
3448 goto out;
3449 }
3450
3451 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3452
3453 btrfs_end_transaction(trans, root);
3454 btrfs_btree_balance_dirty(root);
3455 out:
3456 iput(inode);
3457 return ret;
3458 }
3459
3460 /*
3461 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3462 * this function scans fs tree to find blocks reference the data extent
3463 */
3464 static int find_data_references(struct reloc_control *rc,
3465 struct btrfs_key *extent_key,
3466 struct extent_buffer *leaf,
3467 struct btrfs_extent_data_ref *ref,
3468 struct rb_root *blocks)
3469 {
3470 struct btrfs_path *path;
3471 struct tree_block *block;
3472 struct btrfs_root *root;
3473 struct btrfs_file_extent_item *fi;
3474 struct rb_node *rb_node;
3475 struct btrfs_key key;
3476 u64 ref_root;
3477 u64 ref_objectid;
3478 u64 ref_offset;
3479 u32 ref_count;
3480 u32 nritems;
3481 int err = 0;
3482 int added = 0;
3483 int counted;
3484 int ret;
3485
3486 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3487 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3488 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3489 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3490
3491 /*
3492 * This is an extent belonging to the free space cache, lets just delete
3493 * it and redo the search.
3494 */
3495 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3496 ret = delete_block_group_cache(rc->extent_root->fs_info,
3497 NULL, ref_objectid);
3498 if (ret != -ENOENT)
3499 return ret;
3500 ret = 0;
3501 }
3502
3503 path = btrfs_alloc_path();
3504 if (!path)
3505 return -ENOMEM;
3506 path->reada = 1;
3507
3508 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3509 if (IS_ERR(root)) {
3510 err = PTR_ERR(root);
3511 goto out;
3512 }
3513
3514 key.objectid = ref_objectid;
3515 key.type = BTRFS_EXTENT_DATA_KEY;
3516 if (ref_offset > ((u64)-1 << 32))
3517 key.offset = 0;
3518 else
3519 key.offset = ref_offset;
3520
3521 path->search_commit_root = 1;
3522 path->skip_locking = 1;
3523 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3524 if (ret < 0) {
3525 err = ret;
3526 goto out;
3527 }
3528
3529 leaf = path->nodes[0];
3530 nritems = btrfs_header_nritems(leaf);
3531 /*
3532 * the references in tree blocks that use full backrefs
3533 * are not counted in
3534 */
3535 if (block_use_full_backref(rc, leaf))
3536 counted = 0;
3537 else
3538 counted = 1;
3539 rb_node = tree_search(blocks, leaf->start);
3540 if (rb_node) {
3541 if (counted)
3542 added = 1;
3543 else
3544 path->slots[0] = nritems;
3545 }
3546
3547 while (ref_count > 0) {
3548 while (path->slots[0] >= nritems) {
3549 ret = btrfs_next_leaf(root, path);
3550 if (ret < 0) {
3551 err = ret;
3552 goto out;
3553 }
3554 if (WARN_ON(ret > 0))
3555 goto out;
3556
3557 leaf = path->nodes[0];
3558 nritems = btrfs_header_nritems(leaf);
3559 added = 0;
3560
3561 if (block_use_full_backref(rc, leaf))
3562 counted = 0;
3563 else
3564 counted = 1;
3565 rb_node = tree_search(blocks, leaf->start);
3566 if (rb_node) {
3567 if (counted)
3568 added = 1;
3569 else
3570 path->slots[0] = nritems;
3571 }
3572 }
3573
3574 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3575 if (WARN_ON(key.objectid != ref_objectid ||
3576 key.type != BTRFS_EXTENT_DATA_KEY))
3577 break;
3578
3579 fi = btrfs_item_ptr(leaf, path->slots[0],
3580 struct btrfs_file_extent_item);
3581
3582 if (btrfs_file_extent_type(leaf, fi) ==
3583 BTRFS_FILE_EXTENT_INLINE)
3584 goto next;
3585
3586 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3587 extent_key->objectid)
3588 goto next;
3589
3590 key.offset -= btrfs_file_extent_offset(leaf, fi);
3591 if (key.offset != ref_offset)
3592 goto next;
3593
3594 if (counted)
3595 ref_count--;
3596 if (added)
3597 goto next;
3598
3599 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3600 block = kmalloc(sizeof(*block), GFP_NOFS);
3601 if (!block) {
3602 err = -ENOMEM;
3603 break;
3604 }
3605 block->bytenr = leaf->start;
3606 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3607 block->level = 0;
3608 block->key_ready = 1;
3609 rb_node = tree_insert(blocks, block->bytenr,
3610 &block->rb_node);
3611 if (rb_node)
3612 backref_tree_panic(rb_node, -EEXIST,
3613 block->bytenr);
3614 }
3615 if (counted)
3616 added = 1;
3617 else
3618 path->slots[0] = nritems;
3619 next:
3620 path->slots[0]++;
3621
3622 }
3623 out:
3624 btrfs_free_path(path);
3625 return err;
3626 }
3627
3628 /*
3629 * helper to find all tree blocks that reference a given data extent
3630 */
3631 static noinline_for_stack
3632 int add_data_references(struct reloc_control *rc,
3633 struct btrfs_key *extent_key,
3634 struct btrfs_path *path,
3635 struct rb_root *blocks)
3636 {
3637 struct btrfs_key key;
3638 struct extent_buffer *eb;
3639 struct btrfs_extent_data_ref *dref;
3640 struct btrfs_extent_inline_ref *iref;
3641 unsigned long ptr;
3642 unsigned long end;
3643 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3644 int ret = 0;
3645 int err = 0;
3646
3647 eb = path->nodes[0];
3648 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3649 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3650 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3651 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3652 ptr = end;
3653 else
3654 #endif
3655 ptr += sizeof(struct btrfs_extent_item);
3656
3657 while (ptr < end) {
3658 iref = (struct btrfs_extent_inline_ref *)ptr;
3659 key.type = btrfs_extent_inline_ref_type(eb, iref);
3660 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3661 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3662 ret = __add_tree_block(rc, key.offset, blocksize,
3663 blocks);
3664 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3665 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3666 ret = find_data_references(rc, extent_key,
3667 eb, dref, blocks);
3668 } else {
3669 BUG();
3670 }
3671 if (ret) {
3672 err = ret;
3673 goto out;
3674 }
3675 ptr += btrfs_extent_inline_ref_size(key.type);
3676 }
3677 WARN_ON(ptr > end);
3678
3679 while (1) {
3680 cond_resched();
3681 eb = path->nodes[0];
3682 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3683 ret = btrfs_next_leaf(rc->extent_root, path);
3684 if (ret < 0) {
3685 err = ret;
3686 break;
3687 }
3688 if (ret > 0)
3689 break;
3690 eb = path->nodes[0];
3691 }
3692
3693 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3694 if (key.objectid != extent_key->objectid)
3695 break;
3696
3697 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3698 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3699 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3700 #else
3701 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3702 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3703 #endif
3704 ret = __add_tree_block(rc, key.offset, blocksize,
3705 blocks);
3706 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3707 dref = btrfs_item_ptr(eb, path->slots[0],
3708 struct btrfs_extent_data_ref);
3709 ret = find_data_references(rc, extent_key,
3710 eb, dref, blocks);
3711 } else {
3712 ret = 0;
3713 }
3714 if (ret) {
3715 err = ret;
3716 break;
3717 }
3718 path->slots[0]++;
3719 }
3720 out:
3721 btrfs_release_path(path);
3722 if (err)
3723 free_block_list(blocks);
3724 return err;
3725 }
3726
3727 /*
3728 * helper to find next unprocessed extent
3729 */
3730 static noinline_for_stack
3731 int find_next_extent(struct btrfs_trans_handle *trans,
3732 struct reloc_control *rc, struct btrfs_path *path,
3733 struct btrfs_key *extent_key)
3734 {
3735 struct btrfs_key key;
3736 struct extent_buffer *leaf;
3737 u64 start, end, last;
3738 int ret;
3739
3740 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3741 while (1) {
3742 cond_resched();
3743 if (rc->search_start >= last) {
3744 ret = 1;
3745 break;
3746 }
3747
3748 key.objectid = rc->search_start;
3749 key.type = BTRFS_EXTENT_ITEM_KEY;
3750 key.offset = 0;
3751
3752 path->search_commit_root = 1;
3753 path->skip_locking = 1;
3754 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3755 0, 0);
3756 if (ret < 0)
3757 break;
3758 next:
3759 leaf = path->nodes[0];
3760 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3761 ret = btrfs_next_leaf(rc->extent_root, path);
3762 if (ret != 0)
3763 break;
3764 leaf = path->nodes[0];
3765 }
3766
3767 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3768 if (key.objectid >= last) {
3769 ret = 1;
3770 break;
3771 }
3772
3773 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3774 key.type != BTRFS_METADATA_ITEM_KEY) {
3775 path->slots[0]++;
3776 goto next;
3777 }
3778
3779 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3780 key.objectid + key.offset <= rc->search_start) {
3781 path->slots[0]++;
3782 goto next;
3783 }
3784
3785 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3786 key.objectid + rc->extent_root->leafsize <=
3787 rc->search_start) {
3788 path->slots[0]++;
3789 goto next;
3790 }
3791
3792 ret = find_first_extent_bit(&rc->processed_blocks,
3793 key.objectid, &start, &end,
3794 EXTENT_DIRTY, NULL);
3795
3796 if (ret == 0 && start <= key.objectid) {
3797 btrfs_release_path(path);
3798 rc->search_start = end + 1;
3799 } else {
3800 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3801 rc->search_start = key.objectid + key.offset;
3802 else
3803 rc->search_start = key.objectid +
3804 rc->extent_root->leafsize;
3805 memcpy(extent_key, &key, sizeof(key));
3806 return 0;
3807 }
3808 }
3809 btrfs_release_path(path);
3810 return ret;
3811 }
3812
3813 static void set_reloc_control(struct reloc_control *rc)
3814 {
3815 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3816
3817 mutex_lock(&fs_info->reloc_mutex);
3818 fs_info->reloc_ctl = rc;
3819 mutex_unlock(&fs_info->reloc_mutex);
3820 }
3821
3822 static void unset_reloc_control(struct reloc_control *rc)
3823 {
3824 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3825
3826 mutex_lock(&fs_info->reloc_mutex);
3827 fs_info->reloc_ctl = NULL;
3828 mutex_unlock(&fs_info->reloc_mutex);
3829 }
3830
3831 static int check_extent_flags(u64 flags)
3832 {
3833 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3834 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3835 return 1;
3836 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3837 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3838 return 1;
3839 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3840 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3841 return 1;
3842 return 0;
3843 }
3844
3845 static noinline_for_stack
3846 int prepare_to_relocate(struct reloc_control *rc)
3847 {
3848 struct btrfs_trans_handle *trans;
3849
3850 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3851 BTRFS_BLOCK_RSV_TEMP);
3852 if (!rc->block_rsv)
3853 return -ENOMEM;
3854
3855 memset(&rc->cluster, 0, sizeof(rc->cluster));
3856 rc->search_start = rc->block_group->key.objectid;
3857 rc->extents_found = 0;
3858 rc->nodes_relocated = 0;
3859 rc->merging_rsv_size = 0;
3860 rc->reserved_bytes = 0;
3861 rc->block_rsv->size = rc->extent_root->nodesize *
3862 RELOCATION_RESERVED_NODES;
3863
3864 rc->create_reloc_tree = 1;
3865 set_reloc_control(rc);
3866
3867 trans = btrfs_join_transaction(rc->extent_root);
3868 if (IS_ERR(trans)) {
3869 unset_reloc_control(rc);
3870 /*
3871 * extent tree is not a ref_cow tree and has no reloc_root to
3872 * cleanup. And callers are responsible to free the above
3873 * block rsv.
3874 */
3875 return PTR_ERR(trans);
3876 }
3877 btrfs_commit_transaction(trans, rc->extent_root);
3878 return 0;
3879 }
3880
3881 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3882 {
3883 struct rb_root blocks = RB_ROOT;
3884 struct btrfs_key key;
3885 struct btrfs_trans_handle *trans = NULL;
3886 struct btrfs_path *path;
3887 struct btrfs_extent_item *ei;
3888 u64 flags;
3889 u32 item_size;
3890 int ret;
3891 int err = 0;
3892 int progress = 0;
3893
3894 path = btrfs_alloc_path();
3895 if (!path)
3896 return -ENOMEM;
3897 path->reada = 1;
3898
3899 ret = prepare_to_relocate(rc);
3900 if (ret) {
3901 err = ret;
3902 goto out_free;
3903 }
3904
3905 while (1) {
3906 rc->reserved_bytes = 0;
3907 ret = btrfs_block_rsv_refill(rc->extent_root,
3908 rc->block_rsv, rc->block_rsv->size,
3909 BTRFS_RESERVE_FLUSH_ALL);
3910 if (ret) {
3911 err = ret;
3912 break;
3913 }
3914 progress++;
3915 trans = btrfs_start_transaction(rc->extent_root, 0);
3916 if (IS_ERR(trans)) {
3917 err = PTR_ERR(trans);
3918 trans = NULL;
3919 break;
3920 }
3921 restart:
3922 if (update_backref_cache(trans, &rc->backref_cache)) {
3923 btrfs_end_transaction(trans, rc->extent_root);
3924 continue;
3925 }
3926
3927 ret = find_next_extent(trans, rc, path, &key);
3928 if (ret < 0)
3929 err = ret;
3930 if (ret != 0)
3931 break;
3932
3933 rc->extents_found++;
3934
3935 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3936 struct btrfs_extent_item);
3937 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3938 if (item_size >= sizeof(*ei)) {
3939 flags = btrfs_extent_flags(path->nodes[0], ei);
3940 ret = check_extent_flags(flags);
3941 BUG_ON(ret);
3942
3943 } else {
3944 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3945 u64 ref_owner;
3946 int path_change = 0;
3947
3948 BUG_ON(item_size !=
3949 sizeof(struct btrfs_extent_item_v0));
3950 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3951 &path_change);
3952 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3953 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3954 else
3955 flags = BTRFS_EXTENT_FLAG_DATA;
3956
3957 if (path_change) {
3958 btrfs_release_path(path);
3959
3960 path->search_commit_root = 1;
3961 path->skip_locking = 1;
3962 ret = btrfs_search_slot(NULL, rc->extent_root,
3963 &key, path, 0, 0);
3964 if (ret < 0) {
3965 err = ret;
3966 break;
3967 }
3968 BUG_ON(ret > 0);
3969 }
3970 #else
3971 BUG();
3972 #endif
3973 }
3974
3975 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3976 ret = add_tree_block(rc, &key, path, &blocks);
3977 } else if (rc->stage == UPDATE_DATA_PTRS &&
3978 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3979 ret = add_data_references(rc, &key, path, &blocks);
3980 } else {
3981 btrfs_release_path(path);
3982 ret = 0;
3983 }
3984 if (ret < 0) {
3985 err = ret;
3986 break;
3987 }
3988
3989 if (!RB_EMPTY_ROOT(&blocks)) {
3990 ret = relocate_tree_blocks(trans, rc, &blocks);
3991 if (ret < 0) {
3992 /*
3993 * if we fail to relocate tree blocks, force to update
3994 * backref cache when committing transaction.
3995 */
3996 rc->backref_cache.last_trans = trans->transid - 1;
3997
3998 if (ret != -EAGAIN) {
3999 err = ret;
4000 break;
4001 }
4002 rc->extents_found--;
4003 rc->search_start = key.objectid;
4004 }
4005 }
4006
4007 btrfs_end_transaction_throttle(trans, rc->extent_root);
4008 btrfs_btree_balance_dirty(rc->extent_root);
4009 trans = NULL;
4010
4011 if (rc->stage == MOVE_DATA_EXTENTS &&
4012 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4013 rc->found_file_extent = 1;
4014 ret = relocate_data_extent(rc->data_inode,
4015 &key, &rc->cluster);
4016 if (ret < 0) {
4017 err = ret;
4018 break;
4019 }
4020 }
4021 }
4022 if (trans && progress && err == -ENOSPC) {
4023 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4024 rc->block_group->flags);
4025 if (ret == 0) {
4026 err = 0;
4027 progress = 0;
4028 goto restart;
4029 }
4030 }
4031
4032 btrfs_release_path(path);
4033 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4034 GFP_NOFS);
4035
4036 if (trans) {
4037 btrfs_end_transaction_throttle(trans, rc->extent_root);
4038 btrfs_btree_balance_dirty(rc->extent_root);
4039 }
4040
4041 if (!err) {
4042 ret = relocate_file_extent_cluster(rc->data_inode,
4043 &rc->cluster);
4044 if (ret < 0)
4045 err = ret;
4046 }
4047
4048 rc->create_reloc_tree = 0;
4049 set_reloc_control(rc);
4050
4051 backref_cache_cleanup(&rc->backref_cache);
4052 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4053
4054 err = prepare_to_merge(rc, err);
4055
4056 merge_reloc_roots(rc);
4057
4058 rc->merge_reloc_tree = 0;
4059 unset_reloc_control(rc);
4060 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4061
4062 /* get rid of pinned extents */
4063 trans = btrfs_join_transaction(rc->extent_root);
4064 if (IS_ERR(trans))
4065 err = PTR_ERR(trans);
4066 else
4067 btrfs_commit_transaction(trans, rc->extent_root);
4068 out_free:
4069 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4070 btrfs_free_path(path);
4071 return err;
4072 }
4073
4074 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4075 struct btrfs_root *root, u64 objectid)
4076 {
4077 struct btrfs_path *path;
4078 struct btrfs_inode_item *item;
4079 struct extent_buffer *leaf;
4080 int ret;
4081
4082 path = btrfs_alloc_path();
4083 if (!path)
4084 return -ENOMEM;
4085
4086 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4087 if (ret)
4088 goto out;
4089
4090 leaf = path->nodes[0];
4091 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4092 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4093 btrfs_set_inode_generation(leaf, item, 1);
4094 btrfs_set_inode_size(leaf, item, 0);
4095 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4096 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4097 BTRFS_INODE_PREALLOC);
4098 btrfs_mark_buffer_dirty(leaf);
4099 btrfs_release_path(path);
4100 out:
4101 btrfs_free_path(path);
4102 return ret;
4103 }
4104
4105 /*
4106 * helper to create inode for data relocation.
4107 * the inode is in data relocation tree and its link count is 0
4108 */
4109 static noinline_for_stack
4110 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4111 struct btrfs_block_group_cache *group)
4112 {
4113 struct inode *inode = NULL;
4114 struct btrfs_trans_handle *trans;
4115 struct btrfs_root *root;
4116 struct btrfs_key key;
4117 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4118 int err = 0;
4119
4120 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4121 if (IS_ERR(root))
4122 return ERR_CAST(root);
4123
4124 trans = btrfs_start_transaction(root, 6);
4125 if (IS_ERR(trans))
4126 return ERR_CAST(trans);
4127
4128 err = btrfs_find_free_objectid(root, &objectid);
4129 if (err)
4130 goto out;
4131
4132 err = __insert_orphan_inode(trans, root, objectid);
4133 BUG_ON(err);
4134
4135 key.objectid = objectid;
4136 key.type = BTRFS_INODE_ITEM_KEY;
4137 key.offset = 0;
4138 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4139 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4140 BTRFS_I(inode)->index_cnt = group->key.objectid;
4141
4142 err = btrfs_orphan_add(trans, inode);
4143 out:
4144 btrfs_end_transaction(trans, root);
4145 btrfs_btree_balance_dirty(root);
4146 if (err) {
4147 if (inode)
4148 iput(inode);
4149 inode = ERR_PTR(err);
4150 }
4151 return inode;
4152 }
4153
4154 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4155 {
4156 struct reloc_control *rc;
4157
4158 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4159 if (!rc)
4160 return NULL;
4161
4162 INIT_LIST_HEAD(&rc->reloc_roots);
4163 backref_cache_init(&rc->backref_cache);
4164 mapping_tree_init(&rc->reloc_root_tree);
4165 extent_io_tree_init(&rc->processed_blocks,
4166 fs_info->btree_inode->i_mapping);
4167 return rc;
4168 }
4169
4170 /*
4171 * function to relocate all extents in a block group.
4172 */
4173 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4174 {
4175 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4176 struct reloc_control *rc;
4177 struct inode *inode;
4178 struct btrfs_path *path;
4179 int ret;
4180 int rw = 0;
4181 int err = 0;
4182
4183 rc = alloc_reloc_control(fs_info);
4184 if (!rc)
4185 return -ENOMEM;
4186
4187 rc->extent_root = extent_root;
4188
4189 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4190 BUG_ON(!rc->block_group);
4191
4192 if (!rc->block_group->ro) {
4193 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4194 if (ret) {
4195 err = ret;
4196 goto out;
4197 }
4198 rw = 1;
4199 }
4200
4201 path = btrfs_alloc_path();
4202 if (!path) {
4203 err = -ENOMEM;
4204 goto out;
4205 }
4206
4207 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4208 path);
4209 btrfs_free_path(path);
4210
4211 if (!IS_ERR(inode))
4212 ret = delete_block_group_cache(fs_info, inode, 0);
4213 else
4214 ret = PTR_ERR(inode);
4215
4216 if (ret && ret != -ENOENT) {
4217 err = ret;
4218 goto out;
4219 }
4220
4221 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4222 if (IS_ERR(rc->data_inode)) {
4223 err = PTR_ERR(rc->data_inode);
4224 rc->data_inode = NULL;
4225 goto out;
4226 }
4227
4228 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4229 rc->block_group->key.objectid, rc->block_group->flags);
4230
4231 ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
4232 if (ret < 0) {
4233 err = ret;
4234 goto out;
4235 }
4236 btrfs_wait_ordered_roots(fs_info, -1);
4237
4238 while (1) {
4239 mutex_lock(&fs_info->cleaner_mutex);
4240 ret = relocate_block_group(rc);
4241 mutex_unlock(&fs_info->cleaner_mutex);
4242 if (ret < 0) {
4243 err = ret;
4244 goto out;
4245 }
4246
4247 if (rc->extents_found == 0)
4248 break;
4249
4250 btrfs_info(extent_root->fs_info, "found %llu extents",
4251 rc->extents_found);
4252
4253 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4254 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4255 (u64)-1);
4256 if (ret) {
4257 err = ret;
4258 goto out;
4259 }
4260 invalidate_mapping_pages(rc->data_inode->i_mapping,
4261 0, -1);
4262 rc->stage = UPDATE_DATA_PTRS;
4263 }
4264 }
4265
4266 WARN_ON(rc->block_group->pinned > 0);
4267 WARN_ON(rc->block_group->reserved > 0);
4268 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4269 out:
4270 if (err && rw)
4271 btrfs_set_block_group_rw(extent_root, rc->block_group);
4272 iput(rc->data_inode);
4273 btrfs_put_block_group(rc->block_group);
4274 kfree(rc);
4275 return err;
4276 }
4277
4278 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4279 {
4280 struct btrfs_trans_handle *trans;
4281 int ret, err;
4282
4283 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4284 if (IS_ERR(trans))
4285 return PTR_ERR(trans);
4286
4287 memset(&root->root_item.drop_progress, 0,
4288 sizeof(root->root_item.drop_progress));
4289 root->root_item.drop_level = 0;
4290 btrfs_set_root_refs(&root->root_item, 0);
4291 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4292 &root->root_key, &root->root_item);
4293
4294 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4295 if (err)
4296 return err;
4297 return ret;
4298 }
4299
4300 /*
4301 * recover relocation interrupted by system crash.
4302 *
4303 * this function resumes merging reloc trees with corresponding fs trees.
4304 * this is important for keeping the sharing of tree blocks
4305 */
4306 int btrfs_recover_relocation(struct btrfs_root *root)
4307 {
4308 LIST_HEAD(reloc_roots);
4309 struct btrfs_key key;
4310 struct btrfs_root *fs_root;
4311 struct btrfs_root *reloc_root;
4312 struct btrfs_path *path;
4313 struct extent_buffer *leaf;
4314 struct reloc_control *rc = NULL;
4315 struct btrfs_trans_handle *trans;
4316 int ret;
4317 int err = 0;
4318
4319 path = btrfs_alloc_path();
4320 if (!path)
4321 return -ENOMEM;
4322 path->reada = -1;
4323
4324 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4325 key.type = BTRFS_ROOT_ITEM_KEY;
4326 key.offset = (u64)-1;
4327
4328 while (1) {
4329 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4330 path, 0, 0);
4331 if (ret < 0) {
4332 err = ret;
4333 goto out;
4334 }
4335 if (ret > 0) {
4336 if (path->slots[0] == 0)
4337 break;
4338 path->slots[0]--;
4339 }
4340 leaf = path->nodes[0];
4341 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4342 btrfs_release_path(path);
4343
4344 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4345 key.type != BTRFS_ROOT_ITEM_KEY)
4346 break;
4347
4348 reloc_root = btrfs_read_fs_root(root, &key);
4349 if (IS_ERR(reloc_root)) {
4350 err = PTR_ERR(reloc_root);
4351 goto out;
4352 }
4353
4354 list_add(&reloc_root->root_list, &reloc_roots);
4355
4356 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4357 fs_root = read_fs_root(root->fs_info,
4358 reloc_root->root_key.offset);
4359 if (IS_ERR(fs_root)) {
4360 ret = PTR_ERR(fs_root);
4361 if (ret != -ENOENT) {
4362 err = ret;
4363 goto out;
4364 }
4365 ret = mark_garbage_root(reloc_root);
4366 if (ret < 0) {
4367 err = ret;
4368 goto out;
4369 }
4370 }
4371 }
4372
4373 if (key.offset == 0)
4374 break;
4375
4376 key.offset--;
4377 }
4378 btrfs_release_path(path);
4379
4380 if (list_empty(&reloc_roots))
4381 goto out;
4382
4383 rc = alloc_reloc_control(root->fs_info);
4384 if (!rc) {
4385 err = -ENOMEM;
4386 goto out;
4387 }
4388
4389 rc->extent_root = root->fs_info->extent_root;
4390
4391 set_reloc_control(rc);
4392
4393 trans = btrfs_join_transaction(rc->extent_root);
4394 if (IS_ERR(trans)) {
4395 unset_reloc_control(rc);
4396 err = PTR_ERR(trans);
4397 goto out_free;
4398 }
4399
4400 rc->merge_reloc_tree = 1;
4401
4402 while (!list_empty(&reloc_roots)) {
4403 reloc_root = list_entry(reloc_roots.next,
4404 struct btrfs_root, root_list);
4405 list_del(&reloc_root->root_list);
4406
4407 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4408 list_add_tail(&reloc_root->root_list,
4409 &rc->reloc_roots);
4410 continue;
4411 }
4412
4413 fs_root = read_fs_root(root->fs_info,
4414 reloc_root->root_key.offset);
4415 if (IS_ERR(fs_root)) {
4416 err = PTR_ERR(fs_root);
4417 goto out_free;
4418 }
4419
4420 err = __add_reloc_root(reloc_root);
4421 BUG_ON(err < 0); /* -ENOMEM or logic error */
4422 fs_root->reloc_root = reloc_root;
4423 }
4424
4425 err = btrfs_commit_transaction(trans, rc->extent_root);
4426 if (err)
4427 goto out_free;
4428
4429 merge_reloc_roots(rc);
4430
4431 unset_reloc_control(rc);
4432
4433 trans = btrfs_join_transaction(rc->extent_root);
4434 if (IS_ERR(trans))
4435 err = PTR_ERR(trans);
4436 else
4437 err = btrfs_commit_transaction(trans, rc->extent_root);
4438 out_free:
4439 kfree(rc);
4440 out:
4441 if (!list_empty(&reloc_roots))
4442 free_reloc_roots(&reloc_roots);
4443
4444 btrfs_free_path(path);
4445
4446 if (err == 0) {
4447 /* cleanup orphan inode in data relocation tree */
4448 fs_root = read_fs_root(root->fs_info,
4449 BTRFS_DATA_RELOC_TREE_OBJECTID);
4450 if (IS_ERR(fs_root))
4451 err = PTR_ERR(fs_root);
4452 else
4453 err = btrfs_orphan_cleanup(fs_root);
4454 }
4455 return err;
4456 }
4457
4458 /*
4459 * helper to add ordered checksum for data relocation.
4460 *
4461 * cloning checksum properly handles the nodatasum extents.
4462 * it also saves CPU time to re-calculate the checksum.
4463 */
4464 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4465 {
4466 struct btrfs_ordered_sum *sums;
4467 struct btrfs_ordered_extent *ordered;
4468 struct btrfs_root *root = BTRFS_I(inode)->root;
4469 int ret;
4470 u64 disk_bytenr;
4471 u64 new_bytenr;
4472 LIST_HEAD(list);
4473
4474 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4475 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4476
4477 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4478 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4479 disk_bytenr + len - 1, &list, 0);
4480 if (ret)
4481 goto out;
4482
4483 while (!list_empty(&list)) {
4484 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4485 list_del_init(&sums->list);
4486
4487 /*
4488 * We need to offset the new_bytenr based on where the csum is.
4489 * We need to do this because we will read in entire prealloc
4490 * extents but we may have written to say the middle of the
4491 * prealloc extent, so we need to make sure the csum goes with
4492 * the right disk offset.
4493 *
4494 * We can do this because the data reloc inode refers strictly
4495 * to the on disk bytes, so we don't have to worry about
4496 * disk_len vs real len like with real inodes since it's all
4497 * disk length.
4498 */
4499 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4500 sums->bytenr = new_bytenr;
4501
4502 btrfs_add_ordered_sum(inode, ordered, sums);
4503 }
4504 out:
4505 btrfs_put_ordered_extent(ordered);
4506 return ret;
4507 }
4508
4509 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4510 struct btrfs_root *root, struct extent_buffer *buf,
4511 struct extent_buffer *cow)
4512 {
4513 struct reloc_control *rc;
4514 struct backref_node *node;
4515 int first_cow = 0;
4516 int level;
4517 int ret = 0;
4518
4519 rc = root->fs_info->reloc_ctl;
4520 if (!rc)
4521 return 0;
4522
4523 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4524 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4525
4526 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4527 if (buf == root->node)
4528 __update_reloc_root(root, cow->start);
4529 }
4530
4531 level = btrfs_header_level(buf);
4532 if (btrfs_header_generation(buf) <=
4533 btrfs_root_last_snapshot(&root->root_item))
4534 first_cow = 1;
4535
4536 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4537 rc->create_reloc_tree) {
4538 WARN_ON(!first_cow && level == 0);
4539
4540 node = rc->backref_cache.path[level];
4541 BUG_ON(node->bytenr != buf->start &&
4542 node->new_bytenr != buf->start);
4543
4544 drop_node_buffer(node);
4545 extent_buffer_get(cow);
4546 node->eb = cow;
4547 node->new_bytenr = cow->start;
4548
4549 if (!node->pending) {
4550 list_move_tail(&node->list,
4551 &rc->backref_cache.pending[level]);
4552 node->pending = 1;
4553 }
4554
4555 if (first_cow)
4556 __mark_block_processed(rc, node);
4557
4558 if (first_cow && level > 0)
4559 rc->nodes_relocated += buf->len;
4560 }
4561
4562 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4563 ret = replace_file_extents(trans, rc, root, cow);
4564 return ret;
4565 }
4566
4567 /*
4568 * called before creating snapshot. it calculates metadata reservation
4569 * requried for relocating tree blocks in the snapshot
4570 */
4571 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4572 struct btrfs_pending_snapshot *pending,
4573 u64 *bytes_to_reserve)
4574 {
4575 struct btrfs_root *root;
4576 struct reloc_control *rc;
4577
4578 root = pending->root;
4579 if (!root->reloc_root)
4580 return;
4581
4582 rc = root->fs_info->reloc_ctl;
4583 if (!rc->merge_reloc_tree)
4584 return;
4585
4586 root = root->reloc_root;
4587 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4588 /*
4589 * relocation is in the stage of merging trees. the space
4590 * used by merging a reloc tree is twice the size of
4591 * relocated tree nodes in the worst case. half for cowing
4592 * the reloc tree, half for cowing the fs tree. the space
4593 * used by cowing the reloc tree will be freed after the
4594 * tree is dropped. if we create snapshot, cowing the fs
4595 * tree may use more space than it frees. so we need
4596 * reserve extra space.
4597 */
4598 *bytes_to_reserve += rc->nodes_relocated;
4599 }
4600
4601 /*
4602 * called after snapshot is created. migrate block reservation
4603 * and create reloc root for the newly created snapshot
4604 */
4605 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4606 struct btrfs_pending_snapshot *pending)
4607 {
4608 struct btrfs_root *root = pending->root;
4609 struct btrfs_root *reloc_root;
4610 struct btrfs_root *new_root;
4611 struct reloc_control *rc;
4612 int ret;
4613
4614 if (!root->reloc_root)
4615 return 0;
4616
4617 rc = root->fs_info->reloc_ctl;
4618 rc->merging_rsv_size += rc->nodes_relocated;
4619
4620 if (rc->merge_reloc_tree) {
4621 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4622 rc->block_rsv,
4623 rc->nodes_relocated);
4624 if (ret)
4625 return ret;
4626 }
4627
4628 new_root = pending->snap;
4629 reloc_root = create_reloc_root(trans, root->reloc_root,
4630 new_root->root_key.objectid);
4631 if (IS_ERR(reloc_root))
4632 return PTR_ERR(reloc_root);
4633
4634 ret = __add_reloc_root(reloc_root);
4635 BUG_ON(ret < 0);
4636 new_root->reloc_root = reloc_root;
4637
4638 if (rc->create_reloc_tree)
4639 ret = clone_backref_node(trans, rc, root, reloc_root);
4640 return ret;
4641 }
(deprecated) Btrfs devel tree