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Merge branch 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob07b3b36f40ee51657b248112a6d1f028cea9e364
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\n", 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 (!root->ref_cows)
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 (root->ref_cows &&
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 (!root->ref_cows)
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 (!root->ref_cows)
958 upper->cowonly = 1;
959
960 /*
961 * if we know the block isn't shared
962 * we can void checking its backrefs.
963 */
964 if (btrfs_block_can_be_shared(root, eb))
965 upper->checked = 0;
966 else
967 upper->checked = 1;
968
969 /*
970 * add the block to pending list if we
971 * need check its backrefs, we only do this once
972 * while walking up a tree as we will catch
973 * anything else later on.
974 */
975 if (!upper->checked && need_check) {
976 need_check = false;
977 list_add_tail(&edge->list[UPPER],
978 &list);
979 } else
980 INIT_LIST_HEAD(&edge->list[UPPER]);
981 } else {
982 upper = rb_entry(rb_node, struct backref_node,
983 rb_node);
984 BUG_ON(!upper->checked);
985 INIT_LIST_HEAD(&edge->list[UPPER]);
986 if (!upper->owner)
987 upper->owner = btrfs_header_owner(eb);
988 }
989 list_add_tail(&edge->list[LOWER], &lower->upper);
990 edge->node[LOWER] = lower;
991 edge->node[UPPER] = upper;
992
993 if (rb_node)
994 break;
995 lower = upper;
996 upper = NULL;
997 }
998 btrfs_release_path(path2);
999 next:
1000 if (ptr < end) {
1001 ptr += btrfs_extent_inline_ref_size(key.type);
1002 if (ptr >= end) {
1003 WARN_ON(ptr > end);
1004 ptr = 0;
1005 end = 0;
1006 }
1007 }
1008 if (ptr >= end)
1009 path1->slots[0]++;
1010 }
1011 btrfs_release_path(path1);
1012
1013 cur->checked = 1;
1014 WARN_ON(exist);
1015
1016 /* the pending list isn't empty, take the first block to process */
1017 if (!list_empty(&list)) {
1018 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1019 list_del_init(&edge->list[UPPER]);
1020 cur = edge->node[UPPER];
1021 goto again;
1022 }
1023
1024 /*
1025 * everything goes well, connect backref nodes and insert backref nodes
1026 * into the cache.
1027 */
1028 BUG_ON(!node->checked);
1029 cowonly = node->cowonly;
1030 if (!cowonly) {
1031 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1032 &node->rb_node);
1033 if (rb_node)
1034 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1035 list_add_tail(&node->lower, &cache->leaves);
1036 }
1037
1038 list_for_each_entry(edge, &node->upper, list[LOWER])
1039 list_add_tail(&edge->list[UPPER], &list);
1040
1041 while (!list_empty(&list)) {
1042 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1043 list_del_init(&edge->list[UPPER]);
1044 upper = edge->node[UPPER];
1045 if (upper->detached) {
1046 list_del(&edge->list[LOWER]);
1047 lower = edge->node[LOWER];
1048 free_backref_edge(cache, edge);
1049 if (list_empty(&lower->upper))
1050 list_add(&lower->list, &useless);
1051 continue;
1052 }
1053
1054 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1055 if (upper->lowest) {
1056 list_del_init(&upper->lower);
1057 upper->lowest = 0;
1058 }
1059
1060 list_add_tail(&edge->list[UPPER], &upper->lower);
1061 continue;
1062 }
1063
1064 BUG_ON(!upper->checked);
1065 BUG_ON(cowonly != upper->cowonly);
1066 if (!cowonly) {
1067 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1068 &upper->rb_node);
1069 if (rb_node)
1070 backref_tree_panic(rb_node, -EEXIST,
1071 upper->bytenr);
1072 }
1073
1074 list_add_tail(&edge->list[UPPER], &upper->lower);
1075
1076 list_for_each_entry(edge, &upper->upper, list[LOWER])
1077 list_add_tail(&edge->list[UPPER], &list);
1078 }
1079 /*
1080 * process useless backref nodes. backref nodes for tree leaves
1081 * are deleted from the cache. backref nodes for upper level
1082 * tree blocks are left in the cache to avoid unnecessary backref
1083 * lookup.
1084 */
1085 while (!list_empty(&useless)) {
1086 upper = list_entry(useless.next, struct backref_node, list);
1087 list_del_init(&upper->list);
1088 BUG_ON(!list_empty(&upper->upper));
1089 if (upper == node)
1090 node = NULL;
1091 if (upper->lowest) {
1092 list_del_init(&upper->lower);
1093 upper->lowest = 0;
1094 }
1095 while (!list_empty(&upper->lower)) {
1096 edge = list_entry(upper->lower.next,
1097 struct backref_edge, list[UPPER]);
1098 list_del(&edge->list[UPPER]);
1099 list_del(&edge->list[LOWER]);
1100 lower = edge->node[LOWER];
1101 free_backref_edge(cache, edge);
1102
1103 if (list_empty(&lower->upper))
1104 list_add(&lower->list, &useless);
1105 }
1106 __mark_block_processed(rc, upper);
1107 if (upper->level > 0) {
1108 list_add(&upper->list, &cache->detached);
1109 upper->detached = 1;
1110 } else {
1111 rb_erase(&upper->rb_node, &cache->rb_root);
1112 free_backref_node(cache, upper);
1113 }
1114 }
1115 out:
1116 btrfs_free_path(path1);
1117 btrfs_free_path(path2);
1118 if (err) {
1119 while (!list_empty(&useless)) {
1120 lower = list_entry(useless.next,
1121 struct backref_node, upper);
1122 list_del_init(&lower->upper);
1123 }
1124 upper = node;
1125 INIT_LIST_HEAD(&list);
1126 while (upper) {
1127 if (RB_EMPTY_NODE(&upper->rb_node)) {
1128 list_splice_tail(&upper->upper, &list);
1129 free_backref_node(cache, upper);
1130 }
1131
1132 if (list_empty(&list))
1133 break;
1134
1135 edge = list_entry(list.next, struct backref_edge,
1136 list[LOWER]);
1137 list_del(&edge->list[LOWER]);
1138 upper = edge->node[UPPER];
1139 free_backref_edge(cache, edge);
1140 }
1141 return ERR_PTR(err);
1142 }
1143 BUG_ON(node && node->detached);
1144 return node;
1145 }
1146
1147 /*
1148 * helper to add backref node for the newly created snapshot.
1149 * the backref node is created by cloning backref node that
1150 * corresponds to root of source tree
1151 */
1152 static int clone_backref_node(struct btrfs_trans_handle *trans,
1153 struct reloc_control *rc,
1154 struct btrfs_root *src,
1155 struct btrfs_root *dest)
1156 {
1157 struct btrfs_root *reloc_root = src->reloc_root;
1158 struct backref_cache *cache = &rc->backref_cache;
1159 struct backref_node *node = NULL;
1160 struct backref_node *new_node;
1161 struct backref_edge *edge;
1162 struct backref_edge *new_edge;
1163 struct rb_node *rb_node;
1164
1165 if (cache->last_trans > 0)
1166 update_backref_cache(trans, cache);
1167
1168 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1169 if (rb_node) {
1170 node = rb_entry(rb_node, struct backref_node, rb_node);
1171 if (node->detached)
1172 node = NULL;
1173 else
1174 BUG_ON(node->new_bytenr != reloc_root->node->start);
1175 }
1176
1177 if (!node) {
1178 rb_node = tree_search(&cache->rb_root,
1179 reloc_root->commit_root->start);
1180 if (rb_node) {
1181 node = rb_entry(rb_node, struct backref_node,
1182 rb_node);
1183 BUG_ON(node->detached);
1184 }
1185 }
1186
1187 if (!node)
1188 return 0;
1189
1190 new_node = alloc_backref_node(cache);
1191 if (!new_node)
1192 return -ENOMEM;
1193
1194 new_node->bytenr = dest->node->start;
1195 new_node->level = node->level;
1196 new_node->lowest = node->lowest;
1197 new_node->checked = 1;
1198 new_node->root = dest;
1199
1200 if (!node->lowest) {
1201 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1202 new_edge = alloc_backref_edge(cache);
1203 if (!new_edge)
1204 goto fail;
1205
1206 new_edge->node[UPPER] = new_node;
1207 new_edge->node[LOWER] = edge->node[LOWER];
1208 list_add_tail(&new_edge->list[UPPER],
1209 &new_node->lower);
1210 }
1211 } else {
1212 list_add_tail(&new_node->lower, &cache->leaves);
1213 }
1214
1215 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1216 &new_node->rb_node);
1217 if (rb_node)
1218 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1219
1220 if (!new_node->lowest) {
1221 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1222 list_add_tail(&new_edge->list[LOWER],
1223 &new_edge->node[LOWER]->upper);
1224 }
1225 }
1226 return 0;
1227 fail:
1228 while (!list_empty(&new_node->lower)) {
1229 new_edge = list_entry(new_node->lower.next,
1230 struct backref_edge, list[UPPER]);
1231 list_del(&new_edge->list[UPPER]);
1232 free_backref_edge(cache, new_edge);
1233 }
1234 free_backref_node(cache, new_node);
1235 return -ENOMEM;
1236 }
1237
1238 /*
1239 * helper to add 'address of tree root -> reloc tree' mapping
1240 */
1241 static int __must_check __add_reloc_root(struct btrfs_root *root)
1242 {
1243 struct rb_node *rb_node;
1244 struct mapping_node *node;
1245 struct reloc_control *rc = root->fs_info->reloc_ctl;
1246
1247 node = kmalloc(sizeof(*node), GFP_NOFS);
1248 if (!node)
1249 return -ENOMEM;
1250
1251 node->bytenr = root->node->start;
1252 node->data = root;
1253
1254 spin_lock(&rc->reloc_root_tree.lock);
1255 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1256 node->bytenr, &node->rb_node);
1257 spin_unlock(&rc->reloc_root_tree.lock);
1258 if (rb_node) {
1259 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1260 "for start=%llu while inserting into relocation "
1261 "tree\n", node->bytenr);
1262 kfree(node);
1263 return -EEXIST;
1264 }
1265
1266 list_add_tail(&root->root_list, &rc->reloc_roots);
1267 return 0;
1268 }
1269
1270 /*
1271 * helper to delete the 'address of tree root -> reloc tree'
1272 * mapping
1273 */
1274 static void __del_reloc_root(struct btrfs_root *root)
1275 {
1276 struct rb_node *rb_node;
1277 struct mapping_node *node = NULL;
1278 struct reloc_control *rc = root->fs_info->reloc_ctl;
1279
1280 spin_lock(&rc->reloc_root_tree.lock);
1281 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1282 root->node->start);
1283 if (rb_node) {
1284 node = rb_entry(rb_node, struct mapping_node, rb_node);
1285 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1286 }
1287 spin_unlock(&rc->reloc_root_tree.lock);
1288
1289 if (!node)
1290 return;
1291 BUG_ON((struct btrfs_root *)node->data != root);
1292
1293 spin_lock(&root->fs_info->trans_lock);
1294 list_del_init(&root->root_list);
1295 spin_unlock(&root->fs_info->trans_lock);
1296 kfree(node);
1297 }
1298
1299 /*
1300 * helper to update the 'address of tree root -> reloc tree'
1301 * mapping
1302 */
1303 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1304 {
1305 struct rb_node *rb_node;
1306 struct mapping_node *node = NULL;
1307 struct reloc_control *rc = root->fs_info->reloc_ctl;
1308
1309 spin_lock(&rc->reloc_root_tree.lock);
1310 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1311 root->node->start);
1312 if (rb_node) {
1313 node = rb_entry(rb_node, struct mapping_node, rb_node);
1314 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1315 }
1316 spin_unlock(&rc->reloc_root_tree.lock);
1317
1318 if (!node)
1319 return 0;
1320 BUG_ON((struct btrfs_root *)node->data != root);
1321
1322 spin_lock(&rc->reloc_root_tree.lock);
1323 node->bytenr = new_bytenr;
1324 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1325 node->bytenr, &node->rb_node);
1326 spin_unlock(&rc->reloc_root_tree.lock);
1327 if (rb_node)
1328 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1329 return 0;
1330 }
1331
1332 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1333 struct btrfs_root *root, u64 objectid)
1334 {
1335 struct btrfs_root *reloc_root;
1336 struct extent_buffer *eb;
1337 struct btrfs_root_item *root_item;
1338 struct btrfs_key root_key;
1339 u64 last_snap = 0;
1340 int ret;
1341
1342 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1343 BUG_ON(!root_item);
1344
1345 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1346 root_key.type = BTRFS_ROOT_ITEM_KEY;
1347 root_key.offset = objectid;
1348
1349 if (root->root_key.objectid == objectid) {
1350 /* called by btrfs_init_reloc_root */
1351 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1352 BTRFS_TREE_RELOC_OBJECTID);
1353 BUG_ON(ret);
1354
1355 last_snap = btrfs_root_last_snapshot(&root->root_item);
1356 btrfs_set_root_last_snapshot(&root->root_item,
1357 trans->transid - 1);
1358 } else {
1359 /*
1360 * called by btrfs_reloc_post_snapshot_hook.
1361 * the source tree is a reloc tree, all tree blocks
1362 * modified after it was created have RELOC flag
1363 * set in their headers. so it's OK to not update
1364 * the 'last_snapshot'.
1365 */
1366 ret = btrfs_copy_root(trans, root, root->node, &eb,
1367 BTRFS_TREE_RELOC_OBJECTID);
1368 BUG_ON(ret);
1369 }
1370
1371 memcpy(root_item, &root->root_item, sizeof(*root_item));
1372 btrfs_set_root_bytenr(root_item, eb->start);
1373 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1374 btrfs_set_root_generation(root_item, trans->transid);
1375
1376 if (root->root_key.objectid == objectid) {
1377 btrfs_set_root_refs(root_item, 0);
1378 memset(&root_item->drop_progress, 0,
1379 sizeof(struct btrfs_disk_key));
1380 root_item->drop_level = 0;
1381 /*
1382 * abuse rtransid, it is safe because it is impossible to
1383 * receive data into a relocation tree.
1384 */
1385 btrfs_set_root_rtransid(root_item, last_snap);
1386 btrfs_set_root_otransid(root_item, trans->transid);
1387 }
1388
1389 btrfs_tree_unlock(eb);
1390 free_extent_buffer(eb);
1391
1392 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1393 &root_key, root_item);
1394 BUG_ON(ret);
1395 kfree(root_item);
1396
1397 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1398 BUG_ON(IS_ERR(reloc_root));
1399 reloc_root->last_trans = trans->transid;
1400 return reloc_root;
1401 }
1402
1403 /*
1404 * create reloc tree for a given fs tree. reloc tree is just a
1405 * snapshot of the fs tree with special root objectid.
1406 */
1407 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1408 struct btrfs_root *root)
1409 {
1410 struct btrfs_root *reloc_root;
1411 struct reloc_control *rc = root->fs_info->reloc_ctl;
1412 struct btrfs_block_rsv *rsv;
1413 int clear_rsv = 0;
1414 int ret;
1415
1416 if (root->reloc_root) {
1417 reloc_root = root->reloc_root;
1418 reloc_root->last_trans = trans->transid;
1419 return 0;
1420 }
1421
1422 if (!rc || !rc->create_reloc_tree ||
1423 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1424 return 0;
1425
1426 if (!trans->reloc_reserved) {
1427 rsv = trans->block_rsv;
1428 trans->block_rsv = rc->block_rsv;
1429 clear_rsv = 1;
1430 }
1431 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1432 if (clear_rsv)
1433 trans->block_rsv = rsv;
1434
1435 ret = __add_reloc_root(reloc_root);
1436 BUG_ON(ret < 0);
1437 root->reloc_root = reloc_root;
1438 return 0;
1439 }
1440
1441 /*
1442 * update root item of reloc tree
1443 */
1444 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1445 struct btrfs_root *root)
1446 {
1447 struct btrfs_root *reloc_root;
1448 struct btrfs_root_item *root_item;
1449 int ret;
1450
1451 if (!root->reloc_root)
1452 goto out;
1453
1454 reloc_root = root->reloc_root;
1455 root_item = &reloc_root->root_item;
1456
1457 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1458 btrfs_root_refs(root_item) == 0) {
1459 root->reloc_root = NULL;
1460 __del_reloc_root(reloc_root);
1461 }
1462
1463 if (reloc_root->commit_root != reloc_root->node) {
1464 btrfs_set_root_node(root_item, reloc_root->node);
1465 free_extent_buffer(reloc_root->commit_root);
1466 reloc_root->commit_root = btrfs_root_node(reloc_root);
1467 }
1468
1469 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1470 &reloc_root->root_key, root_item);
1471 BUG_ON(ret);
1472
1473 out:
1474 return 0;
1475 }
1476
1477 /*
1478 * helper to find first cached inode with inode number >= objectid
1479 * in a subvolume
1480 */
1481 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1482 {
1483 struct rb_node *node;
1484 struct rb_node *prev;
1485 struct btrfs_inode *entry;
1486 struct inode *inode;
1487
1488 spin_lock(&root->inode_lock);
1489 again:
1490 node = root->inode_tree.rb_node;
1491 prev = NULL;
1492 while (node) {
1493 prev = node;
1494 entry = rb_entry(node, struct btrfs_inode, rb_node);
1495
1496 if (objectid < btrfs_ino(&entry->vfs_inode))
1497 node = node->rb_left;
1498 else if (objectid > btrfs_ino(&entry->vfs_inode))
1499 node = node->rb_right;
1500 else
1501 break;
1502 }
1503 if (!node) {
1504 while (prev) {
1505 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1506 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1507 node = prev;
1508 break;
1509 }
1510 prev = rb_next(prev);
1511 }
1512 }
1513 while (node) {
1514 entry = rb_entry(node, struct btrfs_inode, rb_node);
1515 inode = igrab(&entry->vfs_inode);
1516 if (inode) {
1517 spin_unlock(&root->inode_lock);
1518 return inode;
1519 }
1520
1521 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1522 if (cond_resched_lock(&root->inode_lock))
1523 goto again;
1524
1525 node = rb_next(node);
1526 }
1527 spin_unlock(&root->inode_lock);
1528 return NULL;
1529 }
1530
1531 static int in_block_group(u64 bytenr,
1532 struct btrfs_block_group_cache *block_group)
1533 {
1534 if (bytenr >= block_group->key.objectid &&
1535 bytenr < block_group->key.objectid + block_group->key.offset)
1536 return 1;
1537 return 0;
1538 }
1539
1540 /*
1541 * get new location of data
1542 */
1543 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1544 u64 bytenr, u64 num_bytes)
1545 {
1546 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1547 struct btrfs_path *path;
1548 struct btrfs_file_extent_item *fi;
1549 struct extent_buffer *leaf;
1550 int ret;
1551
1552 path = btrfs_alloc_path();
1553 if (!path)
1554 return -ENOMEM;
1555
1556 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1557 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1558 bytenr, 0);
1559 if (ret < 0)
1560 goto out;
1561 if (ret > 0) {
1562 ret = -ENOENT;
1563 goto out;
1564 }
1565
1566 leaf = path->nodes[0];
1567 fi = btrfs_item_ptr(leaf, path->slots[0],
1568 struct btrfs_file_extent_item);
1569
1570 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1571 btrfs_file_extent_compression(leaf, fi) ||
1572 btrfs_file_extent_encryption(leaf, fi) ||
1573 btrfs_file_extent_other_encoding(leaf, fi));
1574
1575 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1576 ret = -EINVAL;
1577 goto out;
1578 }
1579
1580 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1581 ret = 0;
1582 out:
1583 btrfs_free_path(path);
1584 return ret;
1585 }
1586
1587 /*
1588 * update file extent items in the tree leaf to point to
1589 * the new locations.
1590 */
1591 static noinline_for_stack
1592 int replace_file_extents(struct btrfs_trans_handle *trans,
1593 struct reloc_control *rc,
1594 struct btrfs_root *root,
1595 struct extent_buffer *leaf)
1596 {
1597 struct btrfs_key key;
1598 struct btrfs_file_extent_item *fi;
1599 struct inode *inode = NULL;
1600 u64 parent;
1601 u64 bytenr;
1602 u64 new_bytenr = 0;
1603 u64 num_bytes;
1604 u64 end;
1605 u32 nritems;
1606 u32 i;
1607 int ret = 0;
1608 int first = 1;
1609 int dirty = 0;
1610
1611 if (rc->stage != UPDATE_DATA_PTRS)
1612 return 0;
1613
1614 /* reloc trees always use full backref */
1615 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1616 parent = leaf->start;
1617 else
1618 parent = 0;
1619
1620 nritems = btrfs_header_nritems(leaf);
1621 for (i = 0; i < nritems; i++) {
1622 cond_resched();
1623 btrfs_item_key_to_cpu(leaf, &key, i);
1624 if (key.type != BTRFS_EXTENT_DATA_KEY)
1625 continue;
1626 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1627 if (btrfs_file_extent_type(leaf, fi) ==
1628 BTRFS_FILE_EXTENT_INLINE)
1629 continue;
1630 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1631 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1632 if (bytenr == 0)
1633 continue;
1634 if (!in_block_group(bytenr, rc->block_group))
1635 continue;
1636
1637 /*
1638 * if we are modifying block in fs tree, wait for readpage
1639 * to complete and drop the extent cache
1640 */
1641 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1642 if (first) {
1643 inode = find_next_inode(root, key.objectid);
1644 first = 0;
1645 } else if (inode && btrfs_ino(inode) < key.objectid) {
1646 btrfs_add_delayed_iput(inode);
1647 inode = find_next_inode(root, key.objectid);
1648 }
1649 if (inode && btrfs_ino(inode) == key.objectid) {
1650 end = key.offset +
1651 btrfs_file_extent_num_bytes(leaf, fi);
1652 WARN_ON(!IS_ALIGNED(key.offset,
1653 root->sectorsize));
1654 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1655 end--;
1656 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1657 key.offset, end);
1658 if (!ret)
1659 continue;
1660
1661 btrfs_drop_extent_cache(inode, key.offset, end,
1662 1);
1663 unlock_extent(&BTRFS_I(inode)->io_tree,
1664 key.offset, end);
1665 }
1666 }
1667
1668 ret = get_new_location(rc->data_inode, &new_bytenr,
1669 bytenr, num_bytes);
1670 if (ret) {
1671 /*
1672 * Don't have to abort since we've not changed anything
1673 * in the file extent yet.
1674 */
1675 break;
1676 }
1677
1678 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1679 dirty = 1;
1680
1681 key.offset -= btrfs_file_extent_offset(leaf, fi);
1682 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1683 num_bytes, parent,
1684 btrfs_header_owner(leaf),
1685 key.objectid, key.offset, 1);
1686 if (ret) {
1687 btrfs_abort_transaction(trans, root, ret);
1688 break;
1689 }
1690
1691 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1692 parent, btrfs_header_owner(leaf),
1693 key.objectid, key.offset, 1);
1694 if (ret) {
1695 btrfs_abort_transaction(trans, root, ret);
1696 break;
1697 }
1698 }
1699 if (dirty)
1700 btrfs_mark_buffer_dirty(leaf);
1701 if (inode)
1702 btrfs_add_delayed_iput(inode);
1703 return ret;
1704 }
1705
1706 static noinline_for_stack
1707 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1708 struct btrfs_path *path, int level)
1709 {
1710 struct btrfs_disk_key key1;
1711 struct btrfs_disk_key key2;
1712 btrfs_node_key(eb, &key1, slot);
1713 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1714 return memcmp(&key1, &key2, sizeof(key1));
1715 }
1716
1717 /*
1718 * try to replace tree blocks in fs tree with the new blocks
1719 * in reloc tree. tree blocks haven't been modified since the
1720 * reloc tree was create can be replaced.
1721 *
1722 * if a block was replaced, level of the block + 1 is returned.
1723 * if no block got replaced, 0 is returned. if there are other
1724 * errors, a negative error number is returned.
1725 */
1726 static noinline_for_stack
1727 int replace_path(struct btrfs_trans_handle *trans,
1728 struct btrfs_root *dest, struct btrfs_root *src,
1729 struct btrfs_path *path, struct btrfs_key *next_key,
1730 int lowest_level, int max_level)
1731 {
1732 struct extent_buffer *eb;
1733 struct extent_buffer *parent;
1734 struct btrfs_key key;
1735 u64 old_bytenr;
1736 u64 new_bytenr;
1737 u64 old_ptr_gen;
1738 u64 new_ptr_gen;
1739 u64 last_snapshot;
1740 u32 blocksize;
1741 int cow = 0;
1742 int level;
1743 int ret;
1744 int slot;
1745
1746 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1747 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1748
1749 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1750 again:
1751 slot = path->slots[lowest_level];
1752 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1753
1754 eb = btrfs_lock_root_node(dest);
1755 btrfs_set_lock_blocking(eb);
1756 level = btrfs_header_level(eb);
1757
1758 if (level < lowest_level) {
1759 btrfs_tree_unlock(eb);
1760 free_extent_buffer(eb);
1761 return 0;
1762 }
1763
1764 if (cow) {
1765 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1766 BUG_ON(ret);
1767 }
1768 btrfs_set_lock_blocking(eb);
1769
1770 if (next_key) {
1771 next_key->objectid = (u64)-1;
1772 next_key->type = (u8)-1;
1773 next_key->offset = (u64)-1;
1774 }
1775
1776 parent = eb;
1777 while (1) {
1778 level = btrfs_header_level(parent);
1779 BUG_ON(level < lowest_level);
1780
1781 ret = btrfs_bin_search(parent, &key, level, &slot);
1782 if (ret && slot > 0)
1783 slot--;
1784
1785 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1786 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1787
1788 old_bytenr = btrfs_node_blockptr(parent, slot);
1789 blocksize = btrfs_level_size(dest, level - 1);
1790 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1791
1792 if (level <= max_level) {
1793 eb = path->nodes[level];
1794 new_bytenr = btrfs_node_blockptr(eb,
1795 path->slots[level]);
1796 new_ptr_gen = btrfs_node_ptr_generation(eb,
1797 path->slots[level]);
1798 } else {
1799 new_bytenr = 0;
1800 new_ptr_gen = 0;
1801 }
1802
1803 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1804 ret = level;
1805 break;
1806 }
1807
1808 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1809 memcmp_node_keys(parent, slot, path, level)) {
1810 if (level <= lowest_level) {
1811 ret = 0;
1812 break;
1813 }
1814
1815 eb = read_tree_block(dest, old_bytenr, blocksize,
1816 old_ptr_gen);
1817 if (!eb || !extent_buffer_uptodate(eb)) {
1818 ret = (!eb) ? -ENOMEM : -EIO;
1819 free_extent_buffer(eb);
1820 break;
1821 }
1822 btrfs_tree_lock(eb);
1823 if (cow) {
1824 ret = btrfs_cow_block(trans, dest, eb, parent,
1825 slot, &eb);
1826 BUG_ON(ret);
1827 }
1828 btrfs_set_lock_blocking(eb);
1829
1830 btrfs_tree_unlock(parent);
1831 free_extent_buffer(parent);
1832
1833 parent = eb;
1834 continue;
1835 }
1836
1837 if (!cow) {
1838 btrfs_tree_unlock(parent);
1839 free_extent_buffer(parent);
1840 cow = 1;
1841 goto again;
1842 }
1843
1844 btrfs_node_key_to_cpu(path->nodes[level], &key,
1845 path->slots[level]);
1846 btrfs_release_path(path);
1847
1848 path->lowest_level = level;
1849 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1850 path->lowest_level = 0;
1851 BUG_ON(ret);
1852
1853 /*
1854 * swap blocks in fs tree and reloc tree.
1855 */
1856 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1857 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1858 btrfs_mark_buffer_dirty(parent);
1859
1860 btrfs_set_node_blockptr(path->nodes[level],
1861 path->slots[level], old_bytenr);
1862 btrfs_set_node_ptr_generation(path->nodes[level],
1863 path->slots[level], old_ptr_gen);
1864 btrfs_mark_buffer_dirty(path->nodes[level]);
1865
1866 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1867 path->nodes[level]->start,
1868 src->root_key.objectid, level - 1, 0,
1869 1);
1870 BUG_ON(ret);
1871 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1872 0, dest->root_key.objectid, level - 1,
1873 0, 1);
1874 BUG_ON(ret);
1875
1876 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1877 path->nodes[level]->start,
1878 src->root_key.objectid, level - 1, 0,
1879 1);
1880 BUG_ON(ret);
1881
1882 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1883 0, dest->root_key.objectid, level - 1,
1884 0, 1);
1885 BUG_ON(ret);
1886
1887 btrfs_unlock_up_safe(path, 0);
1888
1889 ret = level;
1890 break;
1891 }
1892 btrfs_tree_unlock(parent);
1893 free_extent_buffer(parent);
1894 return ret;
1895 }
1896
1897 /*
1898 * helper to find next relocated block in reloc tree
1899 */
1900 static noinline_for_stack
1901 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1902 int *level)
1903 {
1904 struct extent_buffer *eb;
1905 int i;
1906 u64 last_snapshot;
1907 u32 nritems;
1908
1909 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1910
1911 for (i = 0; i < *level; i++) {
1912 free_extent_buffer(path->nodes[i]);
1913 path->nodes[i] = NULL;
1914 }
1915
1916 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1917 eb = path->nodes[i];
1918 nritems = btrfs_header_nritems(eb);
1919 while (path->slots[i] + 1 < nritems) {
1920 path->slots[i]++;
1921 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1922 last_snapshot)
1923 continue;
1924
1925 *level = i;
1926 return 0;
1927 }
1928 free_extent_buffer(path->nodes[i]);
1929 path->nodes[i] = NULL;
1930 }
1931 return 1;
1932 }
1933
1934 /*
1935 * walk down reloc tree to find relocated block of lowest level
1936 */
1937 static noinline_for_stack
1938 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1939 int *level)
1940 {
1941 struct extent_buffer *eb = NULL;
1942 int i;
1943 u64 bytenr;
1944 u64 ptr_gen = 0;
1945 u64 last_snapshot;
1946 u32 blocksize;
1947 u32 nritems;
1948
1949 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1950
1951 for (i = *level; i > 0; i--) {
1952 eb = path->nodes[i];
1953 nritems = btrfs_header_nritems(eb);
1954 while (path->slots[i] < nritems) {
1955 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1956 if (ptr_gen > last_snapshot)
1957 break;
1958 path->slots[i]++;
1959 }
1960 if (path->slots[i] >= nritems) {
1961 if (i == *level)
1962 break;
1963 *level = i + 1;
1964 return 0;
1965 }
1966 if (i == 1) {
1967 *level = i;
1968 return 0;
1969 }
1970
1971 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
1972 blocksize = btrfs_level_size(root, i - 1);
1973 eb = read_tree_block(root, bytenr, blocksize, ptr_gen);
1974 if (!eb || !extent_buffer_uptodate(eb)) {
1975 free_extent_buffer(eb);
1976 return -EIO;
1977 }
1978 BUG_ON(btrfs_header_level(eb) != i - 1);
1979 path->nodes[i - 1] = eb;
1980 path->slots[i - 1] = 0;
1981 }
1982 return 1;
1983 }
1984
1985 /*
1986 * invalidate extent cache for file extents whose key in range of
1987 * [min_key, max_key)
1988 */
1989 static int invalidate_extent_cache(struct btrfs_root *root,
1990 struct btrfs_key *min_key,
1991 struct btrfs_key *max_key)
1992 {
1993 struct inode *inode = NULL;
1994 u64 objectid;
1995 u64 start, end;
1996 u64 ino;
1997
1998 objectid = min_key->objectid;
1999 while (1) {
2000 cond_resched();
2001 iput(inode);
2002
2003 if (objectid > max_key->objectid)
2004 break;
2005
2006 inode = find_next_inode(root, objectid);
2007 if (!inode)
2008 break;
2009 ino = btrfs_ino(inode);
2010
2011 if (ino > max_key->objectid) {
2012 iput(inode);
2013 break;
2014 }
2015
2016 objectid = ino + 1;
2017 if (!S_ISREG(inode->i_mode))
2018 continue;
2019
2020 if (unlikely(min_key->objectid == ino)) {
2021 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2022 continue;
2023 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2024 start = 0;
2025 else {
2026 start = min_key->offset;
2027 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2028 }
2029 } else {
2030 start = 0;
2031 }
2032
2033 if (unlikely(max_key->objectid == ino)) {
2034 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2035 continue;
2036 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2037 end = (u64)-1;
2038 } else {
2039 if (max_key->offset == 0)
2040 continue;
2041 end = max_key->offset;
2042 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2043 end--;
2044 }
2045 } else {
2046 end = (u64)-1;
2047 }
2048
2049 /* the lock_extent waits for readpage to complete */
2050 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2051 btrfs_drop_extent_cache(inode, start, end, 1);
2052 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2053 }
2054 return 0;
2055 }
2056
2057 static int find_next_key(struct btrfs_path *path, int level,
2058 struct btrfs_key *key)
2059
2060 {
2061 while (level < BTRFS_MAX_LEVEL) {
2062 if (!path->nodes[level])
2063 break;
2064 if (path->slots[level] + 1 <
2065 btrfs_header_nritems(path->nodes[level])) {
2066 btrfs_node_key_to_cpu(path->nodes[level], key,
2067 path->slots[level] + 1);
2068 return 0;
2069 }
2070 level++;
2071 }
2072 return 1;
2073 }
2074
2075 /*
2076 * merge the relocated tree blocks in reloc tree with corresponding
2077 * fs tree.
2078 */
2079 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2080 struct btrfs_root *root)
2081 {
2082 LIST_HEAD(inode_list);
2083 struct btrfs_key key;
2084 struct btrfs_key next_key;
2085 struct btrfs_trans_handle *trans = NULL;
2086 struct btrfs_root *reloc_root;
2087 struct btrfs_root_item *root_item;
2088 struct btrfs_path *path;
2089 struct extent_buffer *leaf;
2090 int level;
2091 int max_level;
2092 int replaced = 0;
2093 int ret;
2094 int err = 0;
2095 u32 min_reserved;
2096
2097 path = btrfs_alloc_path();
2098 if (!path)
2099 return -ENOMEM;
2100 path->reada = 1;
2101
2102 reloc_root = root->reloc_root;
2103 root_item = &reloc_root->root_item;
2104
2105 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2106 level = btrfs_root_level(root_item);
2107 extent_buffer_get(reloc_root->node);
2108 path->nodes[level] = reloc_root->node;
2109 path->slots[level] = 0;
2110 } else {
2111 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2112
2113 level = root_item->drop_level;
2114 BUG_ON(level == 0);
2115 path->lowest_level = level;
2116 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2117 path->lowest_level = 0;
2118 if (ret < 0) {
2119 btrfs_free_path(path);
2120 return ret;
2121 }
2122
2123 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2124 path->slots[level]);
2125 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2126
2127 btrfs_unlock_up_safe(path, 0);
2128 }
2129
2130 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2131 memset(&next_key, 0, sizeof(next_key));
2132
2133 while (1) {
2134 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2135 BTRFS_RESERVE_FLUSH_ALL);
2136 if (ret) {
2137 err = ret;
2138 goto out;
2139 }
2140 trans = btrfs_start_transaction(root, 0);
2141 if (IS_ERR(trans)) {
2142 err = PTR_ERR(trans);
2143 trans = NULL;
2144 goto out;
2145 }
2146 trans->block_rsv = rc->block_rsv;
2147
2148 replaced = 0;
2149 max_level = level;
2150
2151 ret = walk_down_reloc_tree(reloc_root, path, &level);
2152 if (ret < 0) {
2153 err = ret;
2154 goto out;
2155 }
2156 if (ret > 0)
2157 break;
2158
2159 if (!find_next_key(path, level, &key) &&
2160 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2161 ret = 0;
2162 } else {
2163 ret = replace_path(trans, root, reloc_root, path,
2164 &next_key, level, max_level);
2165 }
2166 if (ret < 0) {
2167 err = ret;
2168 goto out;
2169 }
2170
2171 if (ret > 0) {
2172 level = ret;
2173 btrfs_node_key_to_cpu(path->nodes[level], &key,
2174 path->slots[level]);
2175 replaced = 1;
2176 }
2177
2178 ret = walk_up_reloc_tree(reloc_root, path, &level);
2179 if (ret > 0)
2180 break;
2181
2182 BUG_ON(level == 0);
2183 /*
2184 * save the merging progress in the drop_progress.
2185 * this is OK since root refs == 1 in this case.
2186 */
2187 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2188 path->slots[level]);
2189 root_item->drop_level = level;
2190
2191 btrfs_end_transaction_throttle(trans, root);
2192 trans = NULL;
2193
2194 btrfs_btree_balance_dirty(root);
2195
2196 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2197 invalidate_extent_cache(root, &key, &next_key);
2198 }
2199
2200 /*
2201 * handle the case only one block in the fs tree need to be
2202 * relocated and the block is tree root.
2203 */
2204 leaf = btrfs_lock_root_node(root);
2205 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2206 btrfs_tree_unlock(leaf);
2207 free_extent_buffer(leaf);
2208 if (ret < 0)
2209 err = ret;
2210 out:
2211 btrfs_free_path(path);
2212
2213 if (err == 0) {
2214 memset(&root_item->drop_progress, 0,
2215 sizeof(root_item->drop_progress));
2216 root_item->drop_level = 0;
2217 btrfs_set_root_refs(root_item, 0);
2218 btrfs_update_reloc_root(trans, root);
2219 }
2220
2221 if (trans)
2222 btrfs_end_transaction_throttle(trans, root);
2223
2224 btrfs_btree_balance_dirty(root);
2225
2226 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2227 invalidate_extent_cache(root, &key, &next_key);
2228
2229 return err;
2230 }
2231
2232 static noinline_for_stack
2233 int prepare_to_merge(struct reloc_control *rc, int err)
2234 {
2235 struct btrfs_root *root = rc->extent_root;
2236 struct btrfs_root *reloc_root;
2237 struct btrfs_trans_handle *trans;
2238 LIST_HEAD(reloc_roots);
2239 u64 num_bytes = 0;
2240 int ret;
2241
2242 mutex_lock(&root->fs_info->reloc_mutex);
2243 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2244 rc->merging_rsv_size += rc->nodes_relocated * 2;
2245 mutex_unlock(&root->fs_info->reloc_mutex);
2246
2247 again:
2248 if (!err) {
2249 num_bytes = rc->merging_rsv_size;
2250 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2251 BTRFS_RESERVE_FLUSH_ALL);
2252 if (ret)
2253 err = ret;
2254 }
2255
2256 trans = btrfs_join_transaction(rc->extent_root);
2257 if (IS_ERR(trans)) {
2258 if (!err)
2259 btrfs_block_rsv_release(rc->extent_root,
2260 rc->block_rsv, num_bytes);
2261 return PTR_ERR(trans);
2262 }
2263
2264 if (!err) {
2265 if (num_bytes != rc->merging_rsv_size) {
2266 btrfs_end_transaction(trans, rc->extent_root);
2267 btrfs_block_rsv_release(rc->extent_root,
2268 rc->block_rsv, num_bytes);
2269 goto again;
2270 }
2271 }
2272
2273 rc->merge_reloc_tree = 1;
2274
2275 while (!list_empty(&rc->reloc_roots)) {
2276 reloc_root = list_entry(rc->reloc_roots.next,
2277 struct btrfs_root, root_list);
2278 list_del_init(&reloc_root->root_list);
2279
2280 root = read_fs_root(reloc_root->fs_info,
2281 reloc_root->root_key.offset);
2282 BUG_ON(IS_ERR(root));
2283 BUG_ON(root->reloc_root != reloc_root);
2284
2285 /*
2286 * set reference count to 1, so btrfs_recover_relocation
2287 * knows it should resumes merging
2288 */
2289 if (!err)
2290 btrfs_set_root_refs(&reloc_root->root_item, 1);
2291 btrfs_update_reloc_root(trans, root);
2292
2293 list_add(&reloc_root->root_list, &reloc_roots);
2294 }
2295
2296 list_splice(&reloc_roots, &rc->reloc_roots);
2297
2298 if (!err)
2299 btrfs_commit_transaction(trans, rc->extent_root);
2300 else
2301 btrfs_end_transaction(trans, rc->extent_root);
2302 return err;
2303 }
2304
2305 static noinline_for_stack
2306 void free_reloc_roots(struct list_head *list)
2307 {
2308 struct btrfs_root *reloc_root;
2309
2310 while (!list_empty(list)) {
2311 reloc_root = list_entry(list->next, struct btrfs_root,
2312 root_list);
2313 __del_reloc_root(reloc_root);
2314 }
2315 }
2316
2317 static noinline_for_stack
2318 int merge_reloc_roots(struct reloc_control *rc)
2319 {
2320 struct btrfs_trans_handle *trans;
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 } else if (!ret) {
2379 /*
2380 * recover the last snapshot tranid to avoid
2381 * the space balance break NOCOW.
2382 */
2383 root = read_fs_root(rc->extent_root->fs_info,
2384 objectid);
2385 if (IS_ERR(root))
2386 continue;
2387
2388 trans = btrfs_join_transaction(root);
2389 BUG_ON(IS_ERR(trans));
2390
2391 /* Check if the fs/file tree was snapshoted or not. */
2392 if (btrfs_root_last_snapshot(&root->root_item) ==
2393 otransid - 1)
2394 btrfs_set_root_last_snapshot(&root->root_item,
2395 last_snap);
2396
2397 btrfs_end_transaction(trans, root);
2398 }
2399 }
2400
2401 if (found) {
2402 found = 0;
2403 goto again;
2404 }
2405 out:
2406 if (ret) {
2407 btrfs_std_error(root->fs_info, ret);
2408 if (!list_empty(&reloc_roots))
2409 free_reloc_roots(&reloc_roots);
2410
2411 /* new reloc root may be added */
2412 mutex_lock(&root->fs_info->reloc_mutex);
2413 list_splice_init(&rc->reloc_roots, &reloc_roots);
2414 mutex_unlock(&root->fs_info->reloc_mutex);
2415 if (!list_empty(&reloc_roots))
2416 free_reloc_roots(&reloc_roots);
2417 }
2418
2419 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2420 return ret;
2421 }
2422
2423 static void free_block_list(struct rb_root *blocks)
2424 {
2425 struct tree_block *block;
2426 struct rb_node *rb_node;
2427 while ((rb_node = rb_first(blocks))) {
2428 block = rb_entry(rb_node, struct tree_block, rb_node);
2429 rb_erase(rb_node, blocks);
2430 kfree(block);
2431 }
2432 }
2433
2434 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2435 struct btrfs_root *reloc_root)
2436 {
2437 struct btrfs_root *root;
2438
2439 if (reloc_root->last_trans == trans->transid)
2440 return 0;
2441
2442 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2443 BUG_ON(IS_ERR(root));
2444 BUG_ON(root->reloc_root != reloc_root);
2445
2446 return btrfs_record_root_in_trans(trans, root);
2447 }
2448
2449 static noinline_for_stack
2450 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2451 struct reloc_control *rc,
2452 struct backref_node *node,
2453 struct backref_edge *edges[])
2454 {
2455 struct backref_node *next;
2456 struct btrfs_root *root;
2457 int index = 0;
2458
2459 next = node;
2460 while (1) {
2461 cond_resched();
2462 next = walk_up_backref(next, edges, &index);
2463 root = next->root;
2464 BUG_ON(!root);
2465 BUG_ON(!root->ref_cows);
2466
2467 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2468 record_reloc_root_in_trans(trans, root);
2469 break;
2470 }
2471
2472 btrfs_record_root_in_trans(trans, root);
2473 root = root->reloc_root;
2474
2475 if (next->new_bytenr != root->node->start) {
2476 BUG_ON(next->new_bytenr);
2477 BUG_ON(!list_empty(&next->list));
2478 next->new_bytenr = root->node->start;
2479 next->root = root;
2480 list_add_tail(&next->list,
2481 &rc->backref_cache.changed);
2482 __mark_block_processed(rc, next);
2483 break;
2484 }
2485
2486 WARN_ON(1);
2487 root = NULL;
2488 next = walk_down_backref(edges, &index);
2489 if (!next || next->level <= node->level)
2490 break;
2491 }
2492 if (!root)
2493 return NULL;
2494
2495 next = node;
2496 /* setup backref node path for btrfs_reloc_cow_block */
2497 while (1) {
2498 rc->backref_cache.path[next->level] = next;
2499 if (--index < 0)
2500 break;
2501 next = edges[index]->node[UPPER];
2502 }
2503 return root;
2504 }
2505
2506 /*
2507 * select a tree root for relocation. return NULL if the block
2508 * is reference counted. we should use do_relocation() in this
2509 * case. return a tree root pointer if the block isn't reference
2510 * counted. return -ENOENT if the block is root of reloc tree.
2511 */
2512 static noinline_for_stack
2513 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2514 struct backref_node *node)
2515 {
2516 struct backref_node *next;
2517 struct btrfs_root *root;
2518 struct btrfs_root *fs_root = NULL;
2519 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2520 int index = 0;
2521
2522 next = node;
2523 while (1) {
2524 cond_resched();
2525 next = walk_up_backref(next, edges, &index);
2526 root = next->root;
2527 BUG_ON(!root);
2528
2529 /* no other choice for non-references counted tree */
2530 if (!root->ref_cows)
2531 return root;
2532
2533 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2534 fs_root = root;
2535
2536 if (next != node)
2537 return NULL;
2538
2539 next = walk_down_backref(edges, &index);
2540 if (!next || next->level <= node->level)
2541 break;
2542 }
2543
2544 if (!fs_root)
2545 return ERR_PTR(-ENOENT);
2546 return fs_root;
2547 }
2548
2549 static noinline_for_stack
2550 u64 calcu_metadata_size(struct reloc_control *rc,
2551 struct backref_node *node, int reserve)
2552 {
2553 struct backref_node *next = node;
2554 struct backref_edge *edge;
2555 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2556 u64 num_bytes = 0;
2557 int index = 0;
2558
2559 BUG_ON(reserve && node->processed);
2560
2561 while (next) {
2562 cond_resched();
2563 while (1) {
2564 if (next->processed && (reserve || next != node))
2565 break;
2566
2567 num_bytes += btrfs_level_size(rc->extent_root,
2568 next->level);
2569
2570 if (list_empty(&next->upper))
2571 break;
2572
2573 edge = list_entry(next->upper.next,
2574 struct backref_edge, list[LOWER]);
2575 edges[index++] = edge;
2576 next = edge->node[UPPER];
2577 }
2578 next = walk_down_backref(edges, &index);
2579 }
2580 return num_bytes;
2581 }
2582
2583 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2584 struct reloc_control *rc,
2585 struct backref_node *node)
2586 {
2587 struct btrfs_root *root = rc->extent_root;
2588 u64 num_bytes;
2589 int ret;
2590 u64 tmp;
2591
2592 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2593
2594 trans->block_rsv = rc->block_rsv;
2595 rc->reserved_bytes += num_bytes;
2596 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2597 BTRFS_RESERVE_FLUSH_ALL);
2598 if (ret) {
2599 if (ret == -EAGAIN) {
2600 tmp = rc->extent_root->nodesize *
2601 RELOCATION_RESERVED_NODES;
2602 while (tmp <= rc->reserved_bytes)
2603 tmp <<= 1;
2604 /*
2605 * only one thread can access block_rsv at this point,
2606 * so we don't need hold lock to protect block_rsv.
2607 * we expand more reservation size here to allow enough
2608 * space for relocation and we will return eailer in
2609 * enospc case.
2610 */
2611 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2612 RELOCATION_RESERVED_NODES;
2613 }
2614 return ret;
2615 }
2616
2617 return 0;
2618 }
2619
2620 /*
2621 * relocate a block tree, and then update pointers in upper level
2622 * blocks that reference the block to point to the new location.
2623 *
2624 * if called by link_to_upper, the block has already been relocated.
2625 * in that case this function just updates pointers.
2626 */
2627 static int do_relocation(struct btrfs_trans_handle *trans,
2628 struct reloc_control *rc,
2629 struct backref_node *node,
2630 struct btrfs_key *key,
2631 struct btrfs_path *path, int lowest)
2632 {
2633 struct backref_node *upper;
2634 struct backref_edge *edge;
2635 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2636 struct btrfs_root *root;
2637 struct extent_buffer *eb;
2638 u32 blocksize;
2639 u64 bytenr;
2640 u64 generation;
2641 int slot;
2642 int ret;
2643 int err = 0;
2644
2645 BUG_ON(lowest && node->eb);
2646
2647 path->lowest_level = node->level + 1;
2648 rc->backref_cache.path[node->level] = node;
2649 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2650 cond_resched();
2651
2652 upper = edge->node[UPPER];
2653 root = select_reloc_root(trans, rc, upper, edges);
2654 BUG_ON(!root);
2655
2656 if (upper->eb && !upper->locked) {
2657 if (!lowest) {
2658 ret = btrfs_bin_search(upper->eb, key,
2659 upper->level, &slot);
2660 BUG_ON(ret);
2661 bytenr = btrfs_node_blockptr(upper->eb, slot);
2662 if (node->eb->start == bytenr)
2663 goto next;
2664 }
2665 drop_node_buffer(upper);
2666 }
2667
2668 if (!upper->eb) {
2669 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2670 if (ret < 0) {
2671 err = ret;
2672 break;
2673 }
2674 BUG_ON(ret > 0);
2675
2676 if (!upper->eb) {
2677 upper->eb = path->nodes[upper->level];
2678 path->nodes[upper->level] = NULL;
2679 } else {
2680 BUG_ON(upper->eb != path->nodes[upper->level]);
2681 }
2682
2683 upper->locked = 1;
2684 path->locks[upper->level] = 0;
2685
2686 slot = path->slots[upper->level];
2687 btrfs_release_path(path);
2688 } else {
2689 ret = btrfs_bin_search(upper->eb, key, upper->level,
2690 &slot);
2691 BUG_ON(ret);
2692 }
2693
2694 bytenr = btrfs_node_blockptr(upper->eb, slot);
2695 if (lowest) {
2696 BUG_ON(bytenr != node->bytenr);
2697 } else {
2698 if (node->eb->start == bytenr)
2699 goto next;
2700 }
2701
2702 blocksize = btrfs_level_size(root, node->level);
2703 generation = btrfs_node_ptr_generation(upper->eb, slot);
2704 eb = read_tree_block(root, bytenr, blocksize, generation);
2705 if (!eb || !extent_buffer_uptodate(eb)) {
2706 free_extent_buffer(eb);
2707 err = -EIO;
2708 goto next;
2709 }
2710 btrfs_tree_lock(eb);
2711 btrfs_set_lock_blocking(eb);
2712
2713 if (!node->eb) {
2714 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2715 slot, &eb);
2716 btrfs_tree_unlock(eb);
2717 free_extent_buffer(eb);
2718 if (ret < 0) {
2719 err = ret;
2720 goto next;
2721 }
2722 BUG_ON(node->eb != eb);
2723 } else {
2724 btrfs_set_node_blockptr(upper->eb, slot,
2725 node->eb->start);
2726 btrfs_set_node_ptr_generation(upper->eb, slot,
2727 trans->transid);
2728 btrfs_mark_buffer_dirty(upper->eb);
2729
2730 ret = btrfs_inc_extent_ref(trans, root,
2731 node->eb->start, blocksize,
2732 upper->eb->start,
2733 btrfs_header_owner(upper->eb),
2734 node->level, 0, 1);
2735 BUG_ON(ret);
2736
2737 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2738 BUG_ON(ret);
2739 }
2740 next:
2741 if (!upper->pending)
2742 drop_node_buffer(upper);
2743 else
2744 unlock_node_buffer(upper);
2745 if (err)
2746 break;
2747 }
2748
2749 if (!err && node->pending) {
2750 drop_node_buffer(node);
2751 list_move_tail(&node->list, &rc->backref_cache.changed);
2752 node->pending = 0;
2753 }
2754
2755 path->lowest_level = 0;
2756 BUG_ON(err == -ENOSPC);
2757 return err;
2758 }
2759
2760 static int link_to_upper(struct btrfs_trans_handle *trans,
2761 struct reloc_control *rc,
2762 struct backref_node *node,
2763 struct btrfs_path *path)
2764 {
2765 struct btrfs_key key;
2766
2767 btrfs_node_key_to_cpu(node->eb, &key, 0);
2768 return do_relocation(trans, rc, node, &key, path, 0);
2769 }
2770
2771 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2772 struct reloc_control *rc,
2773 struct btrfs_path *path, int err)
2774 {
2775 LIST_HEAD(list);
2776 struct backref_cache *cache = &rc->backref_cache;
2777 struct backref_node *node;
2778 int level;
2779 int ret;
2780
2781 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2782 while (!list_empty(&cache->pending[level])) {
2783 node = list_entry(cache->pending[level].next,
2784 struct backref_node, list);
2785 list_move_tail(&node->list, &list);
2786 BUG_ON(!node->pending);
2787
2788 if (!err) {
2789 ret = link_to_upper(trans, rc, node, path);
2790 if (ret < 0)
2791 err = ret;
2792 }
2793 }
2794 list_splice_init(&list, &cache->pending[level]);
2795 }
2796 return err;
2797 }
2798
2799 static void mark_block_processed(struct reloc_control *rc,
2800 u64 bytenr, u32 blocksize)
2801 {
2802 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2803 EXTENT_DIRTY, GFP_NOFS);
2804 }
2805
2806 static void __mark_block_processed(struct reloc_control *rc,
2807 struct backref_node *node)
2808 {
2809 u32 blocksize;
2810 if (node->level == 0 ||
2811 in_block_group(node->bytenr, rc->block_group)) {
2812 blocksize = btrfs_level_size(rc->extent_root, node->level);
2813 mark_block_processed(rc, node->bytenr, blocksize);
2814 }
2815 node->processed = 1;
2816 }
2817
2818 /*
2819 * mark a block and all blocks directly/indirectly reference the block
2820 * as processed.
2821 */
2822 static void update_processed_blocks(struct reloc_control *rc,
2823 struct backref_node *node)
2824 {
2825 struct backref_node *next = node;
2826 struct backref_edge *edge;
2827 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2828 int index = 0;
2829
2830 while (next) {
2831 cond_resched();
2832 while (1) {
2833 if (next->processed)
2834 break;
2835
2836 __mark_block_processed(rc, next);
2837
2838 if (list_empty(&next->upper))
2839 break;
2840
2841 edge = list_entry(next->upper.next,
2842 struct backref_edge, list[LOWER]);
2843 edges[index++] = edge;
2844 next = edge->node[UPPER];
2845 }
2846 next = walk_down_backref(edges, &index);
2847 }
2848 }
2849
2850 static int tree_block_processed(u64 bytenr, u32 blocksize,
2851 struct reloc_control *rc)
2852 {
2853 if (test_range_bit(&rc->processed_blocks, bytenr,
2854 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2855 return 1;
2856 return 0;
2857 }
2858
2859 static int get_tree_block_key(struct reloc_control *rc,
2860 struct tree_block *block)
2861 {
2862 struct extent_buffer *eb;
2863
2864 BUG_ON(block->key_ready);
2865 eb = read_tree_block(rc->extent_root, block->bytenr,
2866 block->key.objectid, block->key.offset);
2867 if (!eb || !extent_buffer_uptodate(eb)) {
2868 free_extent_buffer(eb);
2869 return -EIO;
2870 }
2871 WARN_ON(btrfs_header_level(eb) != block->level);
2872 if (block->level == 0)
2873 btrfs_item_key_to_cpu(eb, &block->key, 0);
2874 else
2875 btrfs_node_key_to_cpu(eb, &block->key, 0);
2876 free_extent_buffer(eb);
2877 block->key_ready = 1;
2878 return 0;
2879 }
2880
2881 static int reada_tree_block(struct reloc_control *rc,
2882 struct tree_block *block)
2883 {
2884 BUG_ON(block->key_ready);
2885 if (block->key.type == BTRFS_METADATA_ITEM_KEY)
2886 readahead_tree_block(rc->extent_root, block->bytenr,
2887 block->key.objectid,
2888 rc->extent_root->leafsize);
2889 else
2890 readahead_tree_block(rc->extent_root, block->bytenr,
2891 block->key.objectid, block->key.offset);
2892 return 0;
2893 }
2894
2895 /*
2896 * helper function to relocate a tree block
2897 */
2898 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2899 struct reloc_control *rc,
2900 struct backref_node *node,
2901 struct btrfs_key *key,
2902 struct btrfs_path *path)
2903 {
2904 struct btrfs_root *root;
2905 int ret = 0;
2906
2907 if (!node)
2908 return 0;
2909
2910 BUG_ON(node->processed);
2911 root = select_one_root(trans, node);
2912 if (root == ERR_PTR(-ENOENT)) {
2913 update_processed_blocks(rc, node);
2914 goto out;
2915 }
2916
2917 if (!root || root->ref_cows) {
2918 ret = reserve_metadata_space(trans, rc, node);
2919 if (ret)
2920 goto out;
2921 }
2922
2923 if (root) {
2924 if (root->ref_cows) {
2925 BUG_ON(node->new_bytenr);
2926 BUG_ON(!list_empty(&node->list));
2927 btrfs_record_root_in_trans(trans, root);
2928 root = root->reloc_root;
2929 node->new_bytenr = root->node->start;
2930 node->root = root;
2931 list_add_tail(&node->list, &rc->backref_cache.changed);
2932 } else {
2933 path->lowest_level = node->level;
2934 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2935 btrfs_release_path(path);
2936 if (ret > 0)
2937 ret = 0;
2938 }
2939 if (!ret)
2940 update_processed_blocks(rc, node);
2941 } else {
2942 ret = do_relocation(trans, rc, node, key, path, 1);
2943 }
2944 out:
2945 if (ret || node->level == 0 || node->cowonly)
2946 remove_backref_node(&rc->backref_cache, node);
2947 return ret;
2948 }
2949
2950 /*
2951 * relocate a list of blocks
2952 */
2953 static noinline_for_stack
2954 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2955 struct reloc_control *rc, struct rb_root *blocks)
2956 {
2957 struct backref_node *node;
2958 struct btrfs_path *path;
2959 struct tree_block *block;
2960 struct rb_node *rb_node;
2961 int ret;
2962 int err = 0;
2963
2964 path = btrfs_alloc_path();
2965 if (!path) {
2966 err = -ENOMEM;
2967 goto out_free_blocks;
2968 }
2969
2970 rb_node = rb_first(blocks);
2971 while (rb_node) {
2972 block = rb_entry(rb_node, struct tree_block, rb_node);
2973 if (!block->key_ready)
2974 reada_tree_block(rc, block);
2975 rb_node = rb_next(rb_node);
2976 }
2977
2978 rb_node = rb_first(blocks);
2979 while (rb_node) {
2980 block = rb_entry(rb_node, struct tree_block, rb_node);
2981 if (!block->key_ready) {
2982 err = get_tree_block_key(rc, block);
2983 if (err)
2984 goto out_free_path;
2985 }
2986 rb_node = rb_next(rb_node);
2987 }
2988
2989 rb_node = rb_first(blocks);
2990 while (rb_node) {
2991 block = rb_entry(rb_node, struct tree_block, rb_node);
2992
2993 node = build_backref_tree(rc, &block->key,
2994 block->level, block->bytenr);
2995 if (IS_ERR(node)) {
2996 err = PTR_ERR(node);
2997 goto out;
2998 }
2999
3000 ret = relocate_tree_block(trans, rc, node, &block->key,
3001 path);
3002 if (ret < 0) {
3003 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3004 err = ret;
3005 goto out;
3006 }
3007 rb_node = rb_next(rb_node);
3008 }
3009 out:
3010 err = finish_pending_nodes(trans, rc, path, err);
3011
3012 out_free_path:
3013 btrfs_free_path(path);
3014 out_free_blocks:
3015 free_block_list(blocks);
3016 return err;
3017 }
3018
3019 static noinline_for_stack
3020 int prealloc_file_extent_cluster(struct inode *inode,
3021 struct file_extent_cluster *cluster)
3022 {
3023 u64 alloc_hint = 0;
3024 u64 start;
3025 u64 end;
3026 u64 offset = BTRFS_I(inode)->index_cnt;
3027 u64 num_bytes;
3028 int nr = 0;
3029 int ret = 0;
3030
3031 BUG_ON(cluster->start != cluster->boundary[0]);
3032 mutex_lock(&inode->i_mutex);
3033
3034 ret = btrfs_check_data_free_space(inode, cluster->end +
3035 1 - cluster->start);
3036 if (ret)
3037 goto out;
3038
3039 while (nr < cluster->nr) {
3040 start = cluster->boundary[nr] - offset;
3041 if (nr + 1 < cluster->nr)
3042 end = cluster->boundary[nr + 1] - 1 - offset;
3043 else
3044 end = cluster->end - offset;
3045
3046 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3047 num_bytes = end + 1 - start;
3048 ret = btrfs_prealloc_file_range(inode, 0, start,
3049 num_bytes, num_bytes,
3050 end + 1, &alloc_hint);
3051 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3052 if (ret)
3053 break;
3054 nr++;
3055 }
3056 btrfs_free_reserved_data_space(inode, cluster->end +
3057 1 - cluster->start);
3058 out:
3059 mutex_unlock(&inode->i_mutex);
3060 return ret;
3061 }
3062
3063 static noinline_for_stack
3064 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3065 u64 block_start)
3066 {
3067 struct btrfs_root *root = BTRFS_I(inode)->root;
3068 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3069 struct extent_map *em;
3070 int ret = 0;
3071
3072 em = alloc_extent_map();
3073 if (!em)
3074 return -ENOMEM;
3075
3076 em->start = start;
3077 em->len = end + 1 - start;
3078 em->block_len = em->len;
3079 em->block_start = block_start;
3080 em->bdev = root->fs_info->fs_devices->latest_bdev;
3081 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3082
3083 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3084 while (1) {
3085 write_lock(&em_tree->lock);
3086 ret = add_extent_mapping(em_tree, em, 0);
3087 write_unlock(&em_tree->lock);
3088 if (ret != -EEXIST) {
3089 free_extent_map(em);
3090 break;
3091 }
3092 btrfs_drop_extent_cache(inode, start, end, 0);
3093 }
3094 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3095 return ret;
3096 }
3097
3098 static int relocate_file_extent_cluster(struct inode *inode,
3099 struct file_extent_cluster *cluster)
3100 {
3101 u64 page_start;
3102 u64 page_end;
3103 u64 offset = BTRFS_I(inode)->index_cnt;
3104 unsigned long index;
3105 unsigned long last_index;
3106 struct page *page;
3107 struct file_ra_state *ra;
3108 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3109 int nr = 0;
3110 int ret = 0;
3111
3112 if (!cluster->nr)
3113 return 0;
3114
3115 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3116 if (!ra)
3117 return -ENOMEM;
3118
3119 ret = prealloc_file_extent_cluster(inode, cluster);
3120 if (ret)
3121 goto out;
3122
3123 file_ra_state_init(ra, inode->i_mapping);
3124
3125 ret = setup_extent_mapping(inode, cluster->start - offset,
3126 cluster->end - offset, cluster->start);
3127 if (ret)
3128 goto out;
3129
3130 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3131 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3132 while (index <= last_index) {
3133 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3134 if (ret)
3135 goto out;
3136
3137 page = find_lock_page(inode->i_mapping, index);
3138 if (!page) {
3139 page_cache_sync_readahead(inode->i_mapping,
3140 ra, NULL, index,
3141 last_index + 1 - index);
3142 page = find_or_create_page(inode->i_mapping, index,
3143 mask);
3144 if (!page) {
3145 btrfs_delalloc_release_metadata(inode,
3146 PAGE_CACHE_SIZE);
3147 ret = -ENOMEM;
3148 goto out;
3149 }
3150 }
3151
3152 if (PageReadahead(page)) {
3153 page_cache_async_readahead(inode->i_mapping,
3154 ra, NULL, page, index,
3155 last_index + 1 - index);
3156 }
3157
3158 if (!PageUptodate(page)) {
3159 btrfs_readpage(NULL, page);
3160 lock_page(page);
3161 if (!PageUptodate(page)) {
3162 unlock_page(page);
3163 page_cache_release(page);
3164 btrfs_delalloc_release_metadata(inode,
3165 PAGE_CACHE_SIZE);
3166 ret = -EIO;
3167 goto out;
3168 }
3169 }
3170
3171 page_start = page_offset(page);
3172 page_end = page_start + PAGE_CACHE_SIZE - 1;
3173
3174 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3175
3176 set_page_extent_mapped(page);
3177
3178 if (nr < cluster->nr &&
3179 page_start + offset == cluster->boundary[nr]) {
3180 set_extent_bits(&BTRFS_I(inode)->io_tree,
3181 page_start, page_end,
3182 EXTENT_BOUNDARY, GFP_NOFS);
3183 nr++;
3184 }
3185
3186 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3187 set_page_dirty(page);
3188
3189 unlock_extent(&BTRFS_I(inode)->io_tree,
3190 page_start, page_end);
3191 unlock_page(page);
3192 page_cache_release(page);
3193
3194 index++;
3195 balance_dirty_pages_ratelimited(inode->i_mapping);
3196 btrfs_throttle(BTRFS_I(inode)->root);
3197 }
3198 WARN_ON(nr != cluster->nr);
3199 out:
3200 kfree(ra);
3201 return ret;
3202 }
3203
3204 static noinline_for_stack
3205 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3206 struct file_extent_cluster *cluster)
3207 {
3208 int ret;
3209
3210 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3211 ret = relocate_file_extent_cluster(inode, cluster);
3212 if (ret)
3213 return ret;
3214 cluster->nr = 0;
3215 }
3216
3217 if (!cluster->nr)
3218 cluster->start = extent_key->objectid;
3219 else
3220 BUG_ON(cluster->nr >= MAX_EXTENTS);
3221 cluster->end = extent_key->objectid + extent_key->offset - 1;
3222 cluster->boundary[cluster->nr] = extent_key->objectid;
3223 cluster->nr++;
3224
3225 if (cluster->nr >= MAX_EXTENTS) {
3226 ret = relocate_file_extent_cluster(inode, cluster);
3227 if (ret)
3228 return ret;
3229 cluster->nr = 0;
3230 }
3231 return 0;
3232 }
3233
3234 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3235 static int get_ref_objectid_v0(struct reloc_control *rc,
3236 struct btrfs_path *path,
3237 struct btrfs_key *extent_key,
3238 u64 *ref_objectid, int *path_change)
3239 {
3240 struct btrfs_key key;
3241 struct extent_buffer *leaf;
3242 struct btrfs_extent_ref_v0 *ref0;
3243 int ret;
3244 int slot;
3245
3246 leaf = path->nodes[0];
3247 slot = path->slots[0];
3248 while (1) {
3249 if (slot >= btrfs_header_nritems(leaf)) {
3250 ret = btrfs_next_leaf(rc->extent_root, path);
3251 if (ret < 0)
3252 return ret;
3253 BUG_ON(ret > 0);
3254 leaf = path->nodes[0];
3255 slot = path->slots[0];
3256 if (path_change)
3257 *path_change = 1;
3258 }
3259 btrfs_item_key_to_cpu(leaf, &key, slot);
3260 if (key.objectid != extent_key->objectid)
3261 return -ENOENT;
3262
3263 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3264 slot++;
3265 continue;
3266 }
3267 ref0 = btrfs_item_ptr(leaf, slot,
3268 struct btrfs_extent_ref_v0);
3269 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3270 break;
3271 }
3272 return 0;
3273 }
3274 #endif
3275
3276 /*
3277 * helper to add a tree block to the list.
3278 * the major work is getting the generation and level of the block
3279 */
3280 static int add_tree_block(struct reloc_control *rc,
3281 struct btrfs_key *extent_key,
3282 struct btrfs_path *path,
3283 struct rb_root *blocks)
3284 {
3285 struct extent_buffer *eb;
3286 struct btrfs_extent_item *ei;
3287 struct btrfs_tree_block_info *bi;
3288 struct tree_block *block;
3289 struct rb_node *rb_node;
3290 u32 item_size;
3291 int level = -1;
3292 u64 generation;
3293
3294 eb = path->nodes[0];
3295 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3296
3297 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3298 item_size >= sizeof(*ei) + sizeof(*bi)) {
3299 ei = btrfs_item_ptr(eb, path->slots[0],
3300 struct btrfs_extent_item);
3301 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3302 bi = (struct btrfs_tree_block_info *)(ei + 1);
3303 level = btrfs_tree_block_level(eb, bi);
3304 } else {
3305 level = (int)extent_key->offset;
3306 }
3307 generation = btrfs_extent_generation(eb, ei);
3308 } else {
3309 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3310 u64 ref_owner;
3311 int ret;
3312
3313 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3314 ret = get_ref_objectid_v0(rc, path, extent_key,
3315 &ref_owner, NULL);
3316 if (ret < 0)
3317 return ret;
3318 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3319 level = (int)ref_owner;
3320 /* FIXME: get real generation */
3321 generation = 0;
3322 #else
3323 BUG();
3324 #endif
3325 }
3326
3327 btrfs_release_path(path);
3328
3329 BUG_ON(level == -1);
3330
3331 block = kmalloc(sizeof(*block), GFP_NOFS);
3332 if (!block)
3333 return -ENOMEM;
3334
3335 block->bytenr = extent_key->objectid;
3336 block->key.objectid = rc->extent_root->leafsize;
3337 block->key.offset = generation;
3338 block->level = level;
3339 block->key_ready = 0;
3340
3341 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3342 if (rb_node)
3343 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3344
3345 return 0;
3346 }
3347
3348 /*
3349 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3350 */
3351 static int __add_tree_block(struct reloc_control *rc,
3352 u64 bytenr, u32 blocksize,
3353 struct rb_root *blocks)
3354 {
3355 struct btrfs_path *path;
3356 struct btrfs_key key;
3357 int ret;
3358 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3359 SKINNY_METADATA);
3360
3361 if (tree_block_processed(bytenr, blocksize, rc))
3362 return 0;
3363
3364 if (tree_search(blocks, bytenr))
3365 return 0;
3366
3367 path = btrfs_alloc_path();
3368 if (!path)
3369 return -ENOMEM;
3370 again:
3371 key.objectid = bytenr;
3372 if (skinny) {
3373 key.type = BTRFS_METADATA_ITEM_KEY;
3374 key.offset = (u64)-1;
3375 } else {
3376 key.type = BTRFS_EXTENT_ITEM_KEY;
3377 key.offset = blocksize;
3378 }
3379
3380 path->search_commit_root = 1;
3381 path->skip_locking = 1;
3382 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3383 if (ret < 0)
3384 goto out;
3385
3386 if (ret > 0 && skinny) {
3387 if (path->slots[0]) {
3388 path->slots[0]--;
3389 btrfs_item_key_to_cpu(path->nodes[0], &key,
3390 path->slots[0]);
3391 if (key.objectid == bytenr &&
3392 (key.type == BTRFS_METADATA_ITEM_KEY ||
3393 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3394 key.offset == blocksize)))
3395 ret = 0;
3396 }
3397
3398 if (ret) {
3399 skinny = false;
3400 btrfs_release_path(path);
3401 goto again;
3402 }
3403 }
3404 BUG_ON(ret);
3405
3406 ret = add_tree_block(rc, &key, path, blocks);
3407 out:
3408 btrfs_free_path(path);
3409 return ret;
3410 }
3411
3412 /*
3413 * helper to check if the block use full backrefs for pointers in it
3414 */
3415 static int block_use_full_backref(struct reloc_control *rc,
3416 struct extent_buffer *eb)
3417 {
3418 u64 flags;
3419 int ret;
3420
3421 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3422 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3423 return 1;
3424
3425 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3426 eb->start, btrfs_header_level(eb), 1,
3427 NULL, &flags);
3428 BUG_ON(ret);
3429
3430 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3431 ret = 1;
3432 else
3433 ret = 0;
3434 return ret;
3435 }
3436
3437 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3438 struct inode *inode, u64 ino)
3439 {
3440 struct btrfs_key key;
3441 struct btrfs_root *root = fs_info->tree_root;
3442 struct btrfs_trans_handle *trans;
3443 int ret = 0;
3444
3445 if (inode)
3446 goto truncate;
3447
3448 key.objectid = ino;
3449 key.type = BTRFS_INODE_ITEM_KEY;
3450 key.offset = 0;
3451
3452 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3453 if (IS_ERR(inode) || is_bad_inode(inode)) {
3454 if (!IS_ERR(inode))
3455 iput(inode);
3456 return -ENOENT;
3457 }
3458
3459 truncate:
3460 ret = btrfs_check_trunc_cache_free_space(root,
3461 &fs_info->global_block_rsv);
3462 if (ret)
3463 goto out;
3464
3465 trans = btrfs_join_transaction(root);
3466 if (IS_ERR(trans)) {
3467 ret = PTR_ERR(trans);
3468 goto out;
3469 }
3470
3471 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3472
3473 btrfs_end_transaction(trans, root);
3474 btrfs_btree_balance_dirty(root);
3475 out:
3476 iput(inode);
3477 return ret;
3478 }
3479
3480 /*
3481 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3482 * this function scans fs tree to find blocks reference the data extent
3483 */
3484 static int find_data_references(struct reloc_control *rc,
3485 struct btrfs_key *extent_key,
3486 struct extent_buffer *leaf,
3487 struct btrfs_extent_data_ref *ref,
3488 struct rb_root *blocks)
3489 {
3490 struct btrfs_path *path;
3491 struct tree_block *block;
3492 struct btrfs_root *root;
3493 struct btrfs_file_extent_item *fi;
3494 struct rb_node *rb_node;
3495 struct btrfs_key key;
3496 u64 ref_root;
3497 u64 ref_objectid;
3498 u64 ref_offset;
3499 u32 ref_count;
3500 u32 nritems;
3501 int err = 0;
3502 int added = 0;
3503 int counted;
3504 int ret;
3505
3506 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3507 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3508 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3509 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3510
3511 /*
3512 * This is an extent belonging to the free space cache, lets just delete
3513 * it and redo the search.
3514 */
3515 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3516 ret = delete_block_group_cache(rc->extent_root->fs_info,
3517 NULL, ref_objectid);
3518 if (ret != -ENOENT)
3519 return ret;
3520 ret = 0;
3521 }
3522
3523 path = btrfs_alloc_path();
3524 if (!path)
3525 return -ENOMEM;
3526 path->reada = 1;
3527
3528 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3529 if (IS_ERR(root)) {
3530 err = PTR_ERR(root);
3531 goto out;
3532 }
3533
3534 key.objectid = ref_objectid;
3535 key.type = BTRFS_EXTENT_DATA_KEY;
3536 if (ref_offset > ((u64)-1 << 32))
3537 key.offset = 0;
3538 else
3539 key.offset = ref_offset;
3540
3541 path->search_commit_root = 1;
3542 path->skip_locking = 1;
3543 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3544 if (ret < 0) {
3545 err = ret;
3546 goto out;
3547 }
3548
3549 leaf = path->nodes[0];
3550 nritems = btrfs_header_nritems(leaf);
3551 /*
3552 * the references in tree blocks that use full backrefs
3553 * are not counted in
3554 */
3555 if (block_use_full_backref(rc, leaf))
3556 counted = 0;
3557 else
3558 counted = 1;
3559 rb_node = tree_search(blocks, leaf->start);
3560 if (rb_node) {
3561 if (counted)
3562 added = 1;
3563 else
3564 path->slots[0] = nritems;
3565 }
3566
3567 while (ref_count > 0) {
3568 while (path->slots[0] >= nritems) {
3569 ret = btrfs_next_leaf(root, path);
3570 if (ret < 0) {
3571 err = ret;
3572 goto out;
3573 }
3574 if (WARN_ON(ret > 0))
3575 goto out;
3576
3577 leaf = path->nodes[0];
3578 nritems = btrfs_header_nritems(leaf);
3579 added = 0;
3580
3581 if (block_use_full_backref(rc, leaf))
3582 counted = 0;
3583 else
3584 counted = 1;
3585 rb_node = tree_search(blocks, leaf->start);
3586 if (rb_node) {
3587 if (counted)
3588 added = 1;
3589 else
3590 path->slots[0] = nritems;
3591 }
3592 }
3593
3594 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3595 if (WARN_ON(key.objectid != ref_objectid ||
3596 key.type != BTRFS_EXTENT_DATA_KEY))
3597 break;
3598
3599 fi = btrfs_item_ptr(leaf, path->slots[0],
3600 struct btrfs_file_extent_item);
3601
3602 if (btrfs_file_extent_type(leaf, fi) ==
3603 BTRFS_FILE_EXTENT_INLINE)
3604 goto next;
3605
3606 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3607 extent_key->objectid)
3608 goto next;
3609
3610 key.offset -= btrfs_file_extent_offset(leaf, fi);
3611 if (key.offset != ref_offset)
3612 goto next;
3613
3614 if (counted)
3615 ref_count--;
3616 if (added)
3617 goto next;
3618
3619 if (!tree_block_processed(leaf->start, leaf->len, rc)) {
3620 block = kmalloc(sizeof(*block), GFP_NOFS);
3621 if (!block) {
3622 err = -ENOMEM;
3623 break;
3624 }
3625 block->bytenr = leaf->start;
3626 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3627 block->level = 0;
3628 block->key_ready = 1;
3629 rb_node = tree_insert(blocks, block->bytenr,
3630 &block->rb_node);
3631 if (rb_node)
3632 backref_tree_panic(rb_node, -EEXIST,
3633 block->bytenr);
3634 }
3635 if (counted)
3636 added = 1;
3637 else
3638 path->slots[0] = nritems;
3639 next:
3640 path->slots[0]++;
3641
3642 }
3643 out:
3644 btrfs_free_path(path);
3645 return err;
3646 }
3647
3648 /*
3649 * helper to find all tree blocks that reference a given data extent
3650 */
3651 static noinline_for_stack
3652 int add_data_references(struct reloc_control *rc,
3653 struct btrfs_key *extent_key,
3654 struct btrfs_path *path,
3655 struct rb_root *blocks)
3656 {
3657 struct btrfs_key key;
3658 struct extent_buffer *eb;
3659 struct btrfs_extent_data_ref *dref;
3660 struct btrfs_extent_inline_ref *iref;
3661 unsigned long ptr;
3662 unsigned long end;
3663 u32 blocksize = btrfs_level_size(rc->extent_root, 0);
3664 int ret = 0;
3665 int err = 0;
3666
3667 eb = path->nodes[0];
3668 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3669 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3670 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3671 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3672 ptr = end;
3673 else
3674 #endif
3675 ptr += sizeof(struct btrfs_extent_item);
3676
3677 while (ptr < end) {
3678 iref = (struct btrfs_extent_inline_ref *)ptr;
3679 key.type = btrfs_extent_inline_ref_type(eb, iref);
3680 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3681 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3682 ret = __add_tree_block(rc, key.offset, blocksize,
3683 blocks);
3684 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3685 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3686 ret = find_data_references(rc, extent_key,
3687 eb, dref, blocks);
3688 } else {
3689 BUG();
3690 }
3691 if (ret) {
3692 err = ret;
3693 goto out;
3694 }
3695 ptr += btrfs_extent_inline_ref_size(key.type);
3696 }
3697 WARN_ON(ptr > end);
3698
3699 while (1) {
3700 cond_resched();
3701 eb = path->nodes[0];
3702 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3703 ret = btrfs_next_leaf(rc->extent_root, path);
3704 if (ret < 0) {
3705 err = ret;
3706 break;
3707 }
3708 if (ret > 0)
3709 break;
3710 eb = path->nodes[0];
3711 }
3712
3713 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3714 if (key.objectid != extent_key->objectid)
3715 break;
3716
3717 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3718 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3719 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3720 #else
3721 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3722 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3723 #endif
3724 ret = __add_tree_block(rc, key.offset, blocksize,
3725 blocks);
3726 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3727 dref = btrfs_item_ptr(eb, path->slots[0],
3728 struct btrfs_extent_data_ref);
3729 ret = find_data_references(rc, extent_key,
3730 eb, dref, blocks);
3731 } else {
3732 ret = 0;
3733 }
3734 if (ret) {
3735 err = ret;
3736 break;
3737 }
3738 path->slots[0]++;
3739 }
3740 out:
3741 btrfs_release_path(path);
3742 if (err)
3743 free_block_list(blocks);
3744 return err;
3745 }
3746
3747 /*
3748 * helper to find next unprocessed extent
3749 */
3750 static noinline_for_stack
3751 int find_next_extent(struct btrfs_trans_handle *trans,
3752 struct reloc_control *rc, struct btrfs_path *path,
3753 struct btrfs_key *extent_key)
3754 {
3755 struct btrfs_key key;
3756 struct extent_buffer *leaf;
3757 u64 start, end, last;
3758 int ret;
3759
3760 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3761 while (1) {
3762 cond_resched();
3763 if (rc->search_start >= last) {
3764 ret = 1;
3765 break;
3766 }
3767
3768 key.objectid = rc->search_start;
3769 key.type = BTRFS_EXTENT_ITEM_KEY;
3770 key.offset = 0;
3771
3772 path->search_commit_root = 1;
3773 path->skip_locking = 1;
3774 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3775 0, 0);
3776 if (ret < 0)
3777 break;
3778 next:
3779 leaf = path->nodes[0];
3780 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3781 ret = btrfs_next_leaf(rc->extent_root, path);
3782 if (ret != 0)
3783 break;
3784 leaf = path->nodes[0];
3785 }
3786
3787 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3788 if (key.objectid >= last) {
3789 ret = 1;
3790 break;
3791 }
3792
3793 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3794 key.type != BTRFS_METADATA_ITEM_KEY) {
3795 path->slots[0]++;
3796 goto next;
3797 }
3798
3799 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3800 key.objectid + key.offset <= rc->search_start) {
3801 path->slots[0]++;
3802 goto next;
3803 }
3804
3805 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3806 key.objectid + rc->extent_root->leafsize <=
3807 rc->search_start) {
3808 path->slots[0]++;
3809 goto next;
3810 }
3811
3812 ret = find_first_extent_bit(&rc->processed_blocks,
3813 key.objectid, &start, &end,
3814 EXTENT_DIRTY, NULL);
3815
3816 if (ret == 0 && start <= key.objectid) {
3817 btrfs_release_path(path);
3818 rc->search_start = end + 1;
3819 } else {
3820 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3821 rc->search_start = key.objectid + key.offset;
3822 else
3823 rc->search_start = key.objectid +
3824 rc->extent_root->leafsize;
3825 memcpy(extent_key, &key, sizeof(key));
3826 return 0;
3827 }
3828 }
3829 btrfs_release_path(path);
3830 return ret;
3831 }
3832
3833 static void set_reloc_control(struct reloc_control *rc)
3834 {
3835 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3836
3837 mutex_lock(&fs_info->reloc_mutex);
3838 fs_info->reloc_ctl = rc;
3839 mutex_unlock(&fs_info->reloc_mutex);
3840 }
3841
3842 static void unset_reloc_control(struct reloc_control *rc)
3843 {
3844 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3845
3846 mutex_lock(&fs_info->reloc_mutex);
3847 fs_info->reloc_ctl = NULL;
3848 mutex_unlock(&fs_info->reloc_mutex);
3849 }
3850
3851 static int check_extent_flags(u64 flags)
3852 {
3853 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3854 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3855 return 1;
3856 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3857 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3858 return 1;
3859 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3860 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3861 return 1;
3862 return 0;
3863 }
3864
3865 static noinline_for_stack
3866 int prepare_to_relocate(struct reloc_control *rc)
3867 {
3868 struct btrfs_trans_handle *trans;
3869
3870 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3871 BTRFS_BLOCK_RSV_TEMP);
3872 if (!rc->block_rsv)
3873 return -ENOMEM;
3874
3875 memset(&rc->cluster, 0, sizeof(rc->cluster));
3876 rc->search_start = rc->block_group->key.objectid;
3877 rc->extents_found = 0;
3878 rc->nodes_relocated = 0;
3879 rc->merging_rsv_size = 0;
3880 rc->reserved_bytes = 0;
3881 rc->block_rsv->size = rc->extent_root->nodesize *
3882 RELOCATION_RESERVED_NODES;
3883
3884 rc->create_reloc_tree = 1;
3885 set_reloc_control(rc);
3886
3887 trans = btrfs_join_transaction(rc->extent_root);
3888 if (IS_ERR(trans)) {
3889 unset_reloc_control(rc);
3890 /*
3891 * extent tree is not a ref_cow tree and has no reloc_root to
3892 * cleanup. And callers are responsible to free the above
3893 * block rsv.
3894 */
3895 return PTR_ERR(trans);
3896 }
3897 btrfs_commit_transaction(trans, rc->extent_root);
3898 return 0;
3899 }
3900
3901 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3902 {
3903 struct rb_root blocks = RB_ROOT;
3904 struct btrfs_key key;
3905 struct btrfs_trans_handle *trans = NULL;
3906 struct btrfs_path *path;
3907 struct btrfs_extent_item *ei;
3908 u64 flags;
3909 u32 item_size;
3910 int ret;
3911 int err = 0;
3912 int progress = 0;
3913
3914 path = btrfs_alloc_path();
3915 if (!path)
3916 return -ENOMEM;
3917 path->reada = 1;
3918
3919 ret = prepare_to_relocate(rc);
3920 if (ret) {
3921 err = ret;
3922 goto out_free;
3923 }
3924
3925 while (1) {
3926 rc->reserved_bytes = 0;
3927 ret = btrfs_block_rsv_refill(rc->extent_root,
3928 rc->block_rsv, rc->block_rsv->size,
3929 BTRFS_RESERVE_FLUSH_ALL);
3930 if (ret) {
3931 err = ret;
3932 break;
3933 }
3934 progress++;
3935 trans = btrfs_start_transaction(rc->extent_root, 0);
3936 if (IS_ERR(trans)) {
3937 err = PTR_ERR(trans);
3938 trans = NULL;
3939 break;
3940 }
3941 restart:
3942 if (update_backref_cache(trans, &rc->backref_cache)) {
3943 btrfs_end_transaction(trans, rc->extent_root);
3944 continue;
3945 }
3946
3947 ret = find_next_extent(trans, rc, path, &key);
3948 if (ret < 0)
3949 err = ret;
3950 if (ret != 0)
3951 break;
3952
3953 rc->extents_found++;
3954
3955 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3956 struct btrfs_extent_item);
3957 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3958 if (item_size >= sizeof(*ei)) {
3959 flags = btrfs_extent_flags(path->nodes[0], ei);
3960 ret = check_extent_flags(flags);
3961 BUG_ON(ret);
3962
3963 } else {
3964 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3965 u64 ref_owner;
3966 int path_change = 0;
3967
3968 BUG_ON(item_size !=
3969 sizeof(struct btrfs_extent_item_v0));
3970 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3971 &path_change);
3972 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3973 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3974 else
3975 flags = BTRFS_EXTENT_FLAG_DATA;
3976
3977 if (path_change) {
3978 btrfs_release_path(path);
3979
3980 path->search_commit_root = 1;
3981 path->skip_locking = 1;
3982 ret = btrfs_search_slot(NULL, rc->extent_root,
3983 &key, path, 0, 0);
3984 if (ret < 0) {
3985 err = ret;
3986 break;
3987 }
3988 BUG_ON(ret > 0);
3989 }
3990 #else
3991 BUG();
3992 #endif
3993 }
3994
3995 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3996 ret = add_tree_block(rc, &key, path, &blocks);
3997 } else if (rc->stage == UPDATE_DATA_PTRS &&
3998 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3999 ret = add_data_references(rc, &key, path, &blocks);
4000 } else {
4001 btrfs_release_path(path);
4002 ret = 0;
4003 }
4004 if (ret < 0) {
4005 err = ret;
4006 break;
4007 }
4008
4009 if (!RB_EMPTY_ROOT(&blocks)) {
4010 ret = relocate_tree_blocks(trans, rc, &blocks);
4011 if (ret < 0) {
4012 /*
4013 * if we fail to relocate tree blocks, force to update
4014 * backref cache when committing transaction.
4015 */
4016 rc->backref_cache.last_trans = trans->transid - 1;
4017
4018 if (ret != -EAGAIN) {
4019 err = ret;
4020 break;
4021 }
4022 rc->extents_found--;
4023 rc->search_start = key.objectid;
4024 }
4025 }
4026
4027 btrfs_end_transaction_throttle(trans, rc->extent_root);
4028 btrfs_btree_balance_dirty(rc->extent_root);
4029 trans = NULL;
4030
4031 if (rc->stage == MOVE_DATA_EXTENTS &&
4032 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4033 rc->found_file_extent = 1;
4034 ret = relocate_data_extent(rc->data_inode,
4035 &key, &rc->cluster);
4036 if (ret < 0) {
4037 err = ret;
4038 break;
4039 }
4040 }
4041 }
4042 if (trans && progress && err == -ENOSPC) {
4043 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4044 rc->block_group->flags);
4045 if (ret == 0) {
4046 err = 0;
4047 progress = 0;
4048 goto restart;
4049 }
4050 }
4051
4052 btrfs_release_path(path);
4053 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4054 GFP_NOFS);
4055
4056 if (trans) {
4057 btrfs_end_transaction_throttle(trans, rc->extent_root);
4058 btrfs_btree_balance_dirty(rc->extent_root);
4059 }
4060
4061 if (!err) {
4062 ret = relocate_file_extent_cluster(rc->data_inode,
4063 &rc->cluster);
4064 if (ret < 0)
4065 err = ret;
4066 }
4067
4068 rc->create_reloc_tree = 0;
4069 set_reloc_control(rc);
4070
4071 backref_cache_cleanup(&rc->backref_cache);
4072 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4073
4074 err = prepare_to_merge(rc, err);
4075
4076 merge_reloc_roots(rc);
4077
4078 rc->merge_reloc_tree = 0;
4079 unset_reloc_control(rc);
4080 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4081
4082 /* get rid of pinned extents */
4083 trans = btrfs_join_transaction(rc->extent_root);
4084 if (IS_ERR(trans))
4085 err = PTR_ERR(trans);
4086 else
4087 btrfs_commit_transaction(trans, rc->extent_root);
4088 out_free:
4089 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4090 btrfs_free_path(path);
4091 return err;
4092 }
4093
4094 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4095 struct btrfs_root *root, u64 objectid)
4096 {
4097 struct btrfs_path *path;
4098 struct btrfs_inode_item *item;
4099 struct extent_buffer *leaf;
4100 int ret;
4101
4102 path = btrfs_alloc_path();
4103 if (!path)
4104 return -ENOMEM;
4105
4106 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4107 if (ret)
4108 goto out;
4109
4110 leaf = path->nodes[0];
4111 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4112 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4113 btrfs_set_inode_generation(leaf, item, 1);
4114 btrfs_set_inode_size(leaf, item, 0);
4115 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4116 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4117 BTRFS_INODE_PREALLOC);
4118 btrfs_mark_buffer_dirty(leaf);
4119 btrfs_release_path(path);
4120 out:
4121 btrfs_free_path(path);
4122 return ret;
4123 }
4124
4125 /*
4126 * helper to create inode for data relocation.
4127 * the inode is in data relocation tree and its link count is 0
4128 */
4129 static noinline_for_stack
4130 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4131 struct btrfs_block_group_cache *group)
4132 {
4133 struct inode *inode = NULL;
4134 struct btrfs_trans_handle *trans;
4135 struct btrfs_root *root;
4136 struct btrfs_key key;
4137 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4138 int err = 0;
4139
4140 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4141 if (IS_ERR(root))
4142 return ERR_CAST(root);
4143
4144 trans = btrfs_start_transaction(root, 6);
4145 if (IS_ERR(trans))
4146 return ERR_CAST(trans);
4147
4148 err = btrfs_find_free_objectid(root, &objectid);
4149 if (err)
4150 goto out;
4151
4152 err = __insert_orphan_inode(trans, root, objectid);
4153 BUG_ON(err);
4154
4155 key.objectid = objectid;
4156 key.type = BTRFS_INODE_ITEM_KEY;
4157 key.offset = 0;
4158 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4159 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4160 BTRFS_I(inode)->index_cnt = group->key.objectid;
4161
4162 err = btrfs_orphan_add(trans, inode);
4163 out:
4164 btrfs_end_transaction(trans, root);
4165 btrfs_btree_balance_dirty(root);
4166 if (err) {
4167 if (inode)
4168 iput(inode);
4169 inode = ERR_PTR(err);
4170 }
4171 return inode;
4172 }
4173
4174 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4175 {
4176 struct reloc_control *rc;
4177
4178 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4179 if (!rc)
4180 return NULL;
4181
4182 INIT_LIST_HEAD(&rc->reloc_roots);
4183 backref_cache_init(&rc->backref_cache);
4184 mapping_tree_init(&rc->reloc_root_tree);
4185 extent_io_tree_init(&rc->processed_blocks,
4186 fs_info->btree_inode->i_mapping);
4187 return rc;
4188 }
4189
4190 /*
4191 * function to relocate all extents in a block group.
4192 */
4193 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4194 {
4195 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4196 struct reloc_control *rc;
4197 struct inode *inode;
4198 struct btrfs_path *path;
4199 int ret;
4200 int rw = 0;
4201 int err = 0;
4202
4203 rc = alloc_reloc_control(fs_info);
4204 if (!rc)
4205 return -ENOMEM;
4206
4207 rc->extent_root = extent_root;
4208
4209 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4210 BUG_ON(!rc->block_group);
4211
4212 if (!rc->block_group->ro) {
4213 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4214 if (ret) {
4215 err = ret;
4216 goto out;
4217 }
4218 rw = 1;
4219 }
4220
4221 path = btrfs_alloc_path();
4222 if (!path) {
4223 err = -ENOMEM;
4224 goto out;
4225 }
4226
4227 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4228 path);
4229 btrfs_free_path(path);
4230
4231 if (!IS_ERR(inode))
4232 ret = delete_block_group_cache(fs_info, inode, 0);
4233 else
4234 ret = PTR_ERR(inode);
4235
4236 if (ret && ret != -ENOENT) {
4237 err = ret;
4238 goto out;
4239 }
4240
4241 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4242 if (IS_ERR(rc->data_inode)) {
4243 err = PTR_ERR(rc->data_inode);
4244 rc->data_inode = NULL;
4245 goto out;
4246 }
4247
4248 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4249 rc->block_group->key.objectid, rc->block_group->flags);
4250
4251 ret = btrfs_start_delalloc_roots(fs_info, 0);
4252 if (ret < 0) {
4253 err = ret;
4254 goto out;
4255 }
4256 btrfs_wait_ordered_roots(fs_info, -1);
4257
4258 while (1) {
4259 mutex_lock(&fs_info->cleaner_mutex);
4260 ret = relocate_block_group(rc);
4261 mutex_unlock(&fs_info->cleaner_mutex);
4262 if (ret < 0) {
4263 err = ret;
4264 goto out;
4265 }
4266
4267 if (rc->extents_found == 0)
4268 break;
4269
4270 btrfs_info(extent_root->fs_info, "found %llu extents",
4271 rc->extents_found);
4272
4273 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4274 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4275 (u64)-1);
4276 if (ret) {
4277 err = ret;
4278 goto out;
4279 }
4280 invalidate_mapping_pages(rc->data_inode->i_mapping,
4281 0, -1);
4282 rc->stage = UPDATE_DATA_PTRS;
4283 }
4284 }
4285
4286 WARN_ON(rc->block_group->pinned > 0);
4287 WARN_ON(rc->block_group->reserved > 0);
4288 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4289 out:
4290 if (err && rw)
4291 btrfs_set_block_group_rw(extent_root, rc->block_group);
4292 iput(rc->data_inode);
4293 btrfs_put_block_group(rc->block_group);
4294 kfree(rc);
4295 return err;
4296 }
4297
4298 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4299 {
4300 struct btrfs_trans_handle *trans;
4301 int ret, err;
4302
4303 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4304 if (IS_ERR(trans))
4305 return PTR_ERR(trans);
4306
4307 memset(&root->root_item.drop_progress, 0,
4308 sizeof(root->root_item.drop_progress));
4309 root->root_item.drop_level = 0;
4310 btrfs_set_root_refs(&root->root_item, 0);
4311 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4312 &root->root_key, &root->root_item);
4313
4314 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4315 if (err)
4316 return err;
4317 return ret;
4318 }
4319
4320 /*
4321 * recover relocation interrupted by system crash.
4322 *
4323 * this function resumes merging reloc trees with corresponding fs trees.
4324 * this is important for keeping the sharing of tree blocks
4325 */
4326 int btrfs_recover_relocation(struct btrfs_root *root)
4327 {
4328 LIST_HEAD(reloc_roots);
4329 struct btrfs_key key;
4330 struct btrfs_root *fs_root;
4331 struct btrfs_root *reloc_root;
4332 struct btrfs_path *path;
4333 struct extent_buffer *leaf;
4334 struct reloc_control *rc = NULL;
4335 struct btrfs_trans_handle *trans;
4336 int ret;
4337 int err = 0;
4338
4339 path = btrfs_alloc_path();
4340 if (!path)
4341 return -ENOMEM;
4342 path->reada = -1;
4343
4344 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4345 key.type = BTRFS_ROOT_ITEM_KEY;
4346 key.offset = (u64)-1;
4347
4348 while (1) {
4349 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4350 path, 0, 0);
4351 if (ret < 0) {
4352 err = ret;
4353 goto out;
4354 }
4355 if (ret > 0) {
4356 if (path->slots[0] == 0)
4357 break;
4358 path->slots[0]--;
4359 }
4360 leaf = path->nodes[0];
4361 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4362 btrfs_release_path(path);
4363
4364 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4365 key.type != BTRFS_ROOT_ITEM_KEY)
4366 break;
4367
4368 reloc_root = btrfs_read_fs_root(root, &key);
4369 if (IS_ERR(reloc_root)) {
4370 err = PTR_ERR(reloc_root);
4371 goto out;
4372 }
4373
4374 list_add(&reloc_root->root_list, &reloc_roots);
4375
4376 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4377 fs_root = read_fs_root(root->fs_info,
4378 reloc_root->root_key.offset);
4379 if (IS_ERR(fs_root)) {
4380 ret = PTR_ERR(fs_root);
4381 if (ret != -ENOENT) {
4382 err = ret;
4383 goto out;
4384 }
4385 ret = mark_garbage_root(reloc_root);
4386 if (ret < 0) {
4387 err = ret;
4388 goto out;
4389 }
4390 }
4391 }
4392
4393 if (key.offset == 0)
4394 break;
4395
4396 key.offset--;
4397 }
4398 btrfs_release_path(path);
4399
4400 if (list_empty(&reloc_roots))
4401 goto out;
4402
4403 rc = alloc_reloc_control(root->fs_info);
4404 if (!rc) {
4405 err = -ENOMEM;
4406 goto out;
4407 }
4408
4409 rc->extent_root = root->fs_info->extent_root;
4410
4411 set_reloc_control(rc);
4412
4413 trans = btrfs_join_transaction(rc->extent_root);
4414 if (IS_ERR(trans)) {
4415 unset_reloc_control(rc);
4416 err = PTR_ERR(trans);
4417 goto out_free;
4418 }
4419
4420 rc->merge_reloc_tree = 1;
4421
4422 while (!list_empty(&reloc_roots)) {
4423 reloc_root = list_entry(reloc_roots.next,
4424 struct btrfs_root, root_list);
4425 list_del(&reloc_root->root_list);
4426
4427 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4428 list_add_tail(&reloc_root->root_list,
4429 &rc->reloc_roots);
4430 continue;
4431 }
4432
4433 fs_root = read_fs_root(root->fs_info,
4434 reloc_root->root_key.offset);
4435 if (IS_ERR(fs_root)) {
4436 err = PTR_ERR(fs_root);
4437 goto out_free;
4438 }
4439
4440 err = __add_reloc_root(reloc_root);
4441 BUG_ON(err < 0); /* -ENOMEM or logic error */
4442 fs_root->reloc_root = reloc_root;
4443 }
4444
4445 err = btrfs_commit_transaction(trans, rc->extent_root);
4446 if (err)
4447 goto out_free;
4448
4449 merge_reloc_roots(rc);
4450
4451 unset_reloc_control(rc);
4452
4453 trans = btrfs_join_transaction(rc->extent_root);
4454 if (IS_ERR(trans))
4455 err = PTR_ERR(trans);
4456 else
4457 err = btrfs_commit_transaction(trans, rc->extent_root);
4458 out_free:
4459 kfree(rc);
4460 out:
4461 if (!list_empty(&reloc_roots))
4462 free_reloc_roots(&reloc_roots);
4463
4464 btrfs_free_path(path);
4465
4466 if (err == 0) {
4467 /* cleanup orphan inode in data relocation tree */
4468 fs_root = read_fs_root(root->fs_info,
4469 BTRFS_DATA_RELOC_TREE_OBJECTID);
4470 if (IS_ERR(fs_root))
4471 err = PTR_ERR(fs_root);
4472 else
4473 err = btrfs_orphan_cleanup(fs_root);
4474 }
4475 return err;
4476 }
4477
4478 /*
4479 * helper to add ordered checksum for data relocation.
4480 *
4481 * cloning checksum properly handles the nodatasum extents.
4482 * it also saves CPU time to re-calculate the checksum.
4483 */
4484 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4485 {
4486 struct btrfs_ordered_sum *sums;
4487 struct btrfs_ordered_extent *ordered;
4488 struct btrfs_root *root = BTRFS_I(inode)->root;
4489 int ret;
4490 u64 disk_bytenr;
4491 u64 new_bytenr;
4492 LIST_HEAD(list);
4493
4494 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4495 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4496
4497 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4498 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4499 disk_bytenr + len - 1, &list, 0);
4500 if (ret)
4501 goto out;
4502
4503 while (!list_empty(&list)) {
4504 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4505 list_del_init(&sums->list);
4506
4507 /*
4508 * We need to offset the new_bytenr based on where the csum is.
4509 * We need to do this because we will read in entire prealloc
4510 * extents but we may have written to say the middle of the
4511 * prealloc extent, so we need to make sure the csum goes with
4512 * the right disk offset.
4513 *
4514 * We can do this because the data reloc inode refers strictly
4515 * to the on disk bytes, so we don't have to worry about
4516 * disk_len vs real len like with real inodes since it's all
4517 * disk length.
4518 */
4519 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4520 sums->bytenr = new_bytenr;
4521
4522 btrfs_add_ordered_sum(inode, ordered, sums);
4523 }
4524 out:
4525 btrfs_put_ordered_extent(ordered);
4526 return ret;
4527 }
4528
4529 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4530 struct btrfs_root *root, struct extent_buffer *buf,
4531 struct extent_buffer *cow)
4532 {
4533 struct reloc_control *rc;
4534 struct backref_node *node;
4535 int first_cow = 0;
4536 int level;
4537 int ret = 0;
4538
4539 rc = root->fs_info->reloc_ctl;
4540 if (!rc)
4541 return 0;
4542
4543 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4544 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4545
4546 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4547 if (buf == root->node)
4548 __update_reloc_root(root, cow->start);
4549 }
4550
4551 level = btrfs_header_level(buf);
4552 if (btrfs_header_generation(buf) <=
4553 btrfs_root_last_snapshot(&root->root_item))
4554 first_cow = 1;
4555
4556 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4557 rc->create_reloc_tree) {
4558 WARN_ON(!first_cow && level == 0);
4559
4560 node = rc->backref_cache.path[level];
4561 BUG_ON(node->bytenr != buf->start &&
4562 node->new_bytenr != buf->start);
4563
4564 drop_node_buffer(node);
4565 extent_buffer_get(cow);
4566 node->eb = cow;
4567 node->new_bytenr = cow->start;
4568
4569 if (!node->pending) {
4570 list_move_tail(&node->list,
4571 &rc->backref_cache.pending[level]);
4572 node->pending = 1;
4573 }
4574
4575 if (first_cow)
4576 __mark_block_processed(rc, node);
4577
4578 if (first_cow && level > 0)
4579 rc->nodes_relocated += buf->len;
4580 }
4581
4582 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4583 ret = replace_file_extents(trans, rc, root, cow);
4584 return ret;
4585 }
4586
4587 /*
4588 * called before creating snapshot. it calculates metadata reservation
4589 * requried for relocating tree blocks in the snapshot
4590 */
4591 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4592 struct btrfs_pending_snapshot *pending,
4593 u64 *bytes_to_reserve)
4594 {
4595 struct btrfs_root *root;
4596 struct reloc_control *rc;
4597
4598 root = pending->root;
4599 if (!root->reloc_root)
4600 return;
4601
4602 rc = root->fs_info->reloc_ctl;
4603 if (!rc->merge_reloc_tree)
4604 return;
4605
4606 root = root->reloc_root;
4607 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4608 /*
4609 * relocation is in the stage of merging trees. the space
4610 * used by merging a reloc tree is twice the size of
4611 * relocated tree nodes in the worst case. half for cowing
4612 * the reloc tree, half for cowing the fs tree. the space
4613 * used by cowing the reloc tree will be freed after the
4614 * tree is dropped. if we create snapshot, cowing the fs
4615 * tree may use more space than it frees. so we need
4616 * reserve extra space.
4617 */
4618 *bytes_to_reserve += rc->nodes_relocated;
4619 }
4620
4621 /*
4622 * called after snapshot is created. migrate block reservation
4623 * and create reloc root for the newly created snapshot
4624 */
4625 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4626 struct btrfs_pending_snapshot *pending)
4627 {
4628 struct btrfs_root *root = pending->root;
4629 struct btrfs_root *reloc_root;
4630 struct btrfs_root *new_root;
4631 struct reloc_control *rc;
4632 int ret;
4633
4634 if (!root->reloc_root)
4635 return 0;
4636
4637 rc = root->fs_info->reloc_ctl;
4638 rc->merging_rsv_size += rc->nodes_relocated;
4639
4640 if (rc->merge_reloc_tree) {
4641 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4642 rc->block_rsv,
4643 rc->nodes_relocated);
4644 if (ret)
4645 return ret;
4646 }
4647
4648 new_root = pending->snap;
4649 reloc_root = create_reloc_root(trans, root->reloc_root,
4650 new_root->root_key.objectid);
4651 if (IS_ERR(reloc_root))
4652 return PTR_ERR(reloc_root);
4653
4654 ret = __add_reloc_root(reloc_root);
4655 BUG_ON(ret < 0);
4656 new_root->reloc_root = reloc_root;
4657
4658 if (rc->create_reloc_tree)
4659 ret = clone_backref_node(trans, rc, root, reloc_root);
4660 return ret;
4661 }
Linux with added FPC-III support