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ARM: pmu: add support for interrupt-affinity property
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blobd83085381bccfa745ee0258b8cab5558afbcd639
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34
35 /*
36 * backref_node, mapping_node and tree_block start with this
37 */
38 struct tree_entry {
39 struct rb_node rb_node;
40 u64 bytenr;
41 };
42
43 /*
44 * present a tree block in the backref cache
45 */
46 struct backref_node {
47 struct rb_node rb_node;
48 u64 bytenr;
49
50 u64 new_bytenr;
51 /* objectid of tree block owner, can be not uptodate */
52 u64 owner;
53 /* link to pending, changed or detached list */
54 struct list_head list;
55 /* list of upper level blocks reference this block */
56 struct list_head upper;
57 /* list of child blocks in the cache */
58 struct list_head lower;
59 /* NULL if this node is not tree root */
60 struct btrfs_root *root;
61 /* extent buffer got by COW the block */
62 struct extent_buffer *eb;
63 /* level of tree block */
64 unsigned int level:8;
65 /* is the block in non-reference counted tree */
66 unsigned int cowonly:1;
67 /* 1 if no child node in the cache */
68 unsigned int lowest:1;
69 /* is the extent buffer locked */
70 unsigned int locked:1;
71 /* has the block been processed */
72 unsigned int processed:1;
73 /* have backrefs of this block been checked */
74 unsigned int checked:1;
75 /*
76 * 1 if corresponding block has been cowed but some upper
77 * level block pointers may not point to the new location
78 */
79 unsigned int pending:1;
80 /*
81 * 1 if the backref node isn't connected to any other
82 * backref node.
83 */
84 unsigned int detached:1;
85 };
86
87 /*
88 * present a block pointer in the backref cache
89 */
90 struct backref_edge {
91 struct list_head list[2];
92 struct backref_node *node[2];
93 };
94
95 #define LOWER 0
96 #define UPPER 1
97 #define RELOCATION_RESERVED_NODES 256
98
99 struct backref_cache {
100 /* red black tree of all backref nodes in the cache */
101 struct rb_root rb_root;
102 /* for passing backref nodes to btrfs_reloc_cow_block */
103 struct backref_node *path[BTRFS_MAX_LEVEL];
104 /*
105 * list of blocks that have been cowed but some block
106 * pointers in upper level blocks may not reflect the
107 * new location
108 */
109 struct list_head pending[BTRFS_MAX_LEVEL];
110 /* list of backref nodes with no child node */
111 struct list_head leaves;
112 /* list of blocks that have been cowed in current transaction */
113 struct list_head changed;
114 /* list of detached backref node. */
115 struct list_head detached;
116
117 u64 last_trans;
118
119 int nr_nodes;
120 int nr_edges;
121 };
122
123 /*
124 * map address of tree root to tree
125 */
126 struct mapping_node {
127 struct rb_node rb_node;
128 u64 bytenr;
129 void *data;
130 };
131
132 struct mapping_tree {
133 struct rb_root rb_root;
134 spinlock_t lock;
135 };
136
137 /*
138 * present a tree block to process
139 */
140 struct tree_block {
141 struct rb_node rb_node;
142 u64 bytenr;
143 struct btrfs_key key;
144 unsigned int level:8;
145 unsigned int key_ready:1;
146 };
147
148 #define MAX_EXTENTS 128
149
150 struct file_extent_cluster {
151 u64 start;
152 u64 end;
153 u64 boundary[MAX_EXTENTS];
154 unsigned int nr;
155 };
156
157 struct reloc_control {
158 /* block group to relocate */
159 struct btrfs_block_group_cache *block_group;
160 /* extent tree */
161 struct btrfs_root *extent_root;
162 /* inode for moving data */
163 struct inode *data_inode;
164
165 struct btrfs_block_rsv *block_rsv;
166
167 struct backref_cache backref_cache;
168
169 struct file_extent_cluster cluster;
170 /* tree blocks have been processed */
171 struct extent_io_tree processed_blocks;
172 /* map start of tree root to corresponding reloc tree */
173 struct mapping_tree reloc_root_tree;
174 /* list of reloc trees */
175 struct list_head reloc_roots;
176 /* size of metadata reservation for merging reloc trees */
177 u64 merging_rsv_size;
178 /* size of relocated tree nodes */
179 u64 nodes_relocated;
180 /* reserved size for block group relocation*/
181 u64 reserved_bytes;
182
183 u64 search_start;
184 u64 extents_found;
185
186 unsigned int stage:8;
187 unsigned int create_reloc_tree:1;
188 unsigned int merge_reloc_tree:1;
189 unsigned int found_file_extent:1;
190 };
191
192 /* stages of data relocation */
193 #define MOVE_DATA_EXTENTS 0
194 #define UPDATE_DATA_PTRS 1
195
196 static void remove_backref_node(struct backref_cache *cache,
197 struct backref_node *node);
198 static void __mark_block_processed(struct reloc_control *rc,
199 struct backref_node *node);
200
201 static void mapping_tree_init(struct mapping_tree *tree)
202 {
203 tree->rb_root = RB_ROOT;
204 spin_lock_init(&tree->lock);
205 }
206
207 static void backref_cache_init(struct backref_cache *cache)
208 {
209 int i;
210 cache->rb_root = RB_ROOT;
211 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
212 INIT_LIST_HEAD(&cache->pending[i]);
213 INIT_LIST_HEAD(&cache->changed);
214 INIT_LIST_HEAD(&cache->detached);
215 INIT_LIST_HEAD(&cache->leaves);
216 }
217
218 static void backref_cache_cleanup(struct backref_cache *cache)
219 {
220 struct backref_node *node;
221 int i;
222
223 while (!list_empty(&cache->detached)) {
224 node = list_entry(cache->detached.next,
225 struct backref_node, list);
226 remove_backref_node(cache, node);
227 }
228
229 while (!list_empty(&cache->leaves)) {
230 node = list_entry(cache->leaves.next,
231 struct backref_node, lower);
232 remove_backref_node(cache, node);
233 }
234
235 cache->last_trans = 0;
236
237 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
238 BUG_ON(!list_empty(&cache->pending[i]));
239 BUG_ON(!list_empty(&cache->changed));
240 BUG_ON(!list_empty(&cache->detached));
241 BUG_ON(!RB_EMPTY_ROOT(&cache->rb_root));
242 BUG_ON(cache->nr_nodes);
243 BUG_ON(cache->nr_edges);
244 }
245
246 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
247 {
248 struct backref_node *node;
249
250 node = kzalloc(sizeof(*node), GFP_NOFS);
251 if (node) {
252 INIT_LIST_HEAD(&node->list);
253 INIT_LIST_HEAD(&node->upper);
254 INIT_LIST_HEAD(&node->lower);
255 RB_CLEAR_NODE(&node->rb_node);
256 cache->nr_nodes++;
257 }
258 return node;
259 }
260
261 static void free_backref_node(struct backref_cache *cache,
262 struct backref_node *node)
263 {
264 if (node) {
265 cache->nr_nodes--;
266 kfree(node);
267 }
268 }
269
270 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
271 {
272 struct backref_edge *edge;
273
274 edge = kzalloc(sizeof(*edge), GFP_NOFS);
275 if (edge)
276 cache->nr_edges++;
277 return edge;
278 }
279
280 static void free_backref_edge(struct backref_cache *cache,
281 struct backref_edge *edge)
282 {
283 if (edge) {
284 cache->nr_edges--;
285 kfree(edge);
286 }
287 }
288
289 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
290 struct rb_node *node)
291 {
292 struct rb_node **p = &root->rb_node;
293 struct rb_node *parent = NULL;
294 struct tree_entry *entry;
295
296 while (*p) {
297 parent = *p;
298 entry = rb_entry(parent, struct tree_entry, rb_node);
299
300 if (bytenr < entry->bytenr)
301 p = &(*p)->rb_left;
302 else if (bytenr > entry->bytenr)
303 p = &(*p)->rb_right;
304 else
305 return parent;
306 }
307
308 rb_link_node(node, parent, p);
309 rb_insert_color(node, root);
310 return NULL;
311 }
312
313 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
314 {
315 struct rb_node *n = root->rb_node;
316 struct tree_entry *entry;
317
318 while (n) {
319 entry = rb_entry(n, struct tree_entry, rb_node);
320
321 if (bytenr < entry->bytenr)
322 n = n->rb_left;
323 else if (bytenr > entry->bytenr)
324 n = n->rb_right;
325 else
326 return n;
327 }
328 return NULL;
329 }
330
331 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
332 {
333
334 struct btrfs_fs_info *fs_info = NULL;
335 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
336 rb_node);
337 if (bnode->root)
338 fs_info = bnode->root->fs_info;
339 btrfs_panic(fs_info, errno, "Inconsistency in backref cache "
340 "found at offset %llu", bytenr);
341 }
342
343 /*
344 * walk up backref nodes until reach node presents tree root
345 */
346 static struct backref_node *walk_up_backref(struct backref_node *node,
347 struct backref_edge *edges[],
348 int *index)
349 {
350 struct backref_edge *edge;
351 int idx = *index;
352
353 while (!list_empty(&node->upper)) {
354 edge = list_entry(node->upper.next,
355 struct backref_edge, list[LOWER]);
356 edges[idx++] = edge;
357 node = edge->node[UPPER];
358 }
359 BUG_ON(node->detached);
360 *index = idx;
361 return node;
362 }
363
364 /*
365 * walk down backref nodes to find start of next reference path
366 */
367 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
368 int *index)
369 {
370 struct backref_edge *edge;
371 struct backref_node *lower;
372 int idx = *index;
373
374 while (idx > 0) {
375 edge = edges[idx - 1];
376 lower = edge->node[LOWER];
377 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
378 idx--;
379 continue;
380 }
381 edge = list_entry(edge->list[LOWER].next,
382 struct backref_edge, list[LOWER]);
383 edges[idx - 1] = edge;
384 *index = idx;
385 return edge->node[UPPER];
386 }
387 *index = 0;
388 return NULL;
389 }
390
391 static void unlock_node_buffer(struct backref_node *node)
392 {
393 if (node->locked) {
394 btrfs_tree_unlock(node->eb);
395 node->locked = 0;
396 }
397 }
398
399 static void drop_node_buffer(struct backref_node *node)
400 {
401 if (node->eb) {
402 unlock_node_buffer(node);
403 free_extent_buffer(node->eb);
404 node->eb = NULL;
405 }
406 }
407
408 static void drop_backref_node(struct backref_cache *tree,
409 struct backref_node *node)
410 {
411 BUG_ON(!list_empty(&node->upper));
412
413 drop_node_buffer(node);
414 list_del(&node->list);
415 list_del(&node->lower);
416 if (!RB_EMPTY_NODE(&node->rb_node))
417 rb_erase(&node->rb_node, &tree->rb_root);
418 free_backref_node(tree, node);
419 }
420
421 /*
422 * remove a backref node from the backref cache
423 */
424 static void remove_backref_node(struct backref_cache *cache,
425 struct backref_node *node)
426 {
427 struct backref_node *upper;
428 struct backref_edge *edge;
429
430 if (!node)
431 return;
432
433 BUG_ON(!node->lowest && !node->detached);
434 while (!list_empty(&node->upper)) {
435 edge = list_entry(node->upper.next, struct backref_edge,
436 list[LOWER]);
437 upper = edge->node[UPPER];
438 list_del(&edge->list[LOWER]);
439 list_del(&edge->list[UPPER]);
440 free_backref_edge(cache, edge);
441
442 if (RB_EMPTY_NODE(&upper->rb_node)) {
443 BUG_ON(!list_empty(&node->upper));
444 drop_backref_node(cache, node);
445 node = upper;
446 node->lowest = 1;
447 continue;
448 }
449 /*
450 * add the node to leaf node list if no other
451 * child block cached.
452 */
453 if (list_empty(&upper->lower)) {
454 list_add_tail(&upper->lower, &cache->leaves);
455 upper->lowest = 1;
456 }
457 }
458
459 drop_backref_node(cache, node);
460 }
461
462 static void update_backref_node(struct backref_cache *cache,
463 struct backref_node *node, u64 bytenr)
464 {
465 struct rb_node *rb_node;
466 rb_erase(&node->rb_node, &cache->rb_root);
467 node->bytenr = bytenr;
468 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
469 if (rb_node)
470 backref_tree_panic(rb_node, -EEXIST, bytenr);
471 }
472
473 /*
474 * update backref cache after a transaction commit
475 */
476 static int update_backref_cache(struct btrfs_trans_handle *trans,
477 struct backref_cache *cache)
478 {
479 struct backref_node *node;
480 int level = 0;
481
482 if (cache->last_trans == 0) {
483 cache->last_trans = trans->transid;
484 return 0;
485 }
486
487 if (cache->last_trans == trans->transid)
488 return 0;
489
490 /*
491 * detached nodes are used to avoid unnecessary backref
492 * lookup. transaction commit changes the extent tree.
493 * so the detached nodes are no longer useful.
494 */
495 while (!list_empty(&cache->detached)) {
496 node = list_entry(cache->detached.next,
497 struct backref_node, list);
498 remove_backref_node(cache, node);
499 }
500
501 while (!list_empty(&cache->changed)) {
502 node = list_entry(cache->changed.next,
503 struct backref_node, list);
504 list_del_init(&node->list);
505 BUG_ON(node->pending);
506 update_backref_node(cache, node, node->new_bytenr);
507 }
508
509 /*
510 * some nodes can be left in the pending list if there were
511 * errors during processing the pending nodes.
512 */
513 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
514 list_for_each_entry(node, &cache->pending[level], list) {
515 BUG_ON(!node->pending);
516 if (node->bytenr == node->new_bytenr)
517 continue;
518 update_backref_node(cache, node, node->new_bytenr);
519 }
520 }
521
522 cache->last_trans = 0;
523 return 1;
524 }
525
526
527 static int should_ignore_root(struct btrfs_root *root)
528 {
529 struct btrfs_root *reloc_root;
530
531 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
532 return 0;
533
534 reloc_root = root->reloc_root;
535 if (!reloc_root)
536 return 0;
537
538 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
539 root->fs_info->running_transaction->transid - 1)
540 return 0;
541 /*
542 * if there is reloc tree and it was created in previous
543 * transaction backref lookup can find the reloc tree,
544 * so backref node for the fs tree root is useless for
545 * relocation.
546 */
547 return 1;
548 }
549 /*
550 * find reloc tree by address of tree root
551 */
552 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
553 u64 bytenr)
554 {
555 struct rb_node *rb_node;
556 struct mapping_node *node;
557 struct btrfs_root *root = NULL;
558
559 spin_lock(&rc->reloc_root_tree.lock);
560 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
561 if (rb_node) {
562 node = rb_entry(rb_node, struct mapping_node, rb_node);
563 root = (struct btrfs_root *)node->data;
564 }
565 spin_unlock(&rc->reloc_root_tree.lock);
566 return root;
567 }
568
569 static int is_cowonly_root(u64 root_objectid)
570 {
571 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
572 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
573 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
574 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
575 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
576 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
577 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
578 root_objectid == BTRFS_QUOTA_TREE_OBJECTID)
579 return 1;
580 return 0;
581 }
582
583 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
584 u64 root_objectid)
585 {
586 struct btrfs_key key;
587
588 key.objectid = root_objectid;
589 key.type = BTRFS_ROOT_ITEM_KEY;
590 if (is_cowonly_root(root_objectid))
591 key.offset = 0;
592 else
593 key.offset = (u64)-1;
594
595 return btrfs_get_fs_root(fs_info, &key, false);
596 }
597
598 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
599 static noinline_for_stack
600 struct btrfs_root *find_tree_root(struct reloc_control *rc,
601 struct extent_buffer *leaf,
602 struct btrfs_extent_ref_v0 *ref0)
603 {
604 struct btrfs_root *root;
605 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
606 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
607
608 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
609
610 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
611 BUG_ON(IS_ERR(root));
612
613 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
614 generation != btrfs_root_generation(&root->root_item))
615 return NULL;
616
617 return root;
618 }
619 #endif
620
621 static noinline_for_stack
622 int find_inline_backref(struct extent_buffer *leaf, int slot,
623 unsigned long *ptr, unsigned long *end)
624 {
625 struct btrfs_key key;
626 struct btrfs_extent_item *ei;
627 struct btrfs_tree_block_info *bi;
628 u32 item_size;
629
630 btrfs_item_key_to_cpu(leaf, &key, slot);
631
632 item_size = btrfs_item_size_nr(leaf, slot);
633 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
634 if (item_size < sizeof(*ei)) {
635 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
636 return 1;
637 }
638 #endif
639 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
640 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
641 BTRFS_EXTENT_FLAG_TREE_BLOCK));
642
643 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
644 item_size <= sizeof(*ei) + sizeof(*bi)) {
645 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
646 return 1;
647 }
648 if (key.type == BTRFS_METADATA_ITEM_KEY &&
649 item_size <= sizeof(*ei)) {
650 WARN_ON(item_size < sizeof(*ei));
651 return 1;
652 }
653
654 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
655 bi = (struct btrfs_tree_block_info *)(ei + 1);
656 *ptr = (unsigned long)(bi + 1);
657 } else {
658 *ptr = (unsigned long)(ei + 1);
659 }
660 *end = (unsigned long)ei + item_size;
661 return 0;
662 }
663
664 /*
665 * build backref tree for a given tree block. root of the backref tree
666 * corresponds the tree block, leaves of the backref tree correspond
667 * roots of b-trees that reference the tree block.
668 *
669 * the basic idea of this function is check backrefs of a given block
670 * to find upper level blocks that refernece the block, and then check
671 * bakcrefs of these upper level blocks recursively. the recursion stop
672 * when tree root is reached or backrefs for the block is cached.
673 *
674 * NOTE: if we find backrefs for a block are cached, we know backrefs
675 * for all upper level blocks that directly/indirectly reference the
676 * block are also cached.
677 */
678 static noinline_for_stack
679 struct backref_node *build_backref_tree(struct reloc_control *rc,
680 struct btrfs_key *node_key,
681 int level, u64 bytenr)
682 {
683 struct backref_cache *cache = &rc->backref_cache;
684 struct btrfs_path *path1;
685 struct btrfs_path *path2;
686 struct extent_buffer *eb;
687 struct btrfs_root *root;
688 struct backref_node *cur;
689 struct backref_node *upper;
690 struct backref_node *lower;
691 struct backref_node *node = NULL;
692 struct backref_node *exist = NULL;
693 struct backref_edge *edge;
694 struct rb_node *rb_node;
695 struct btrfs_key key;
696 unsigned long end;
697 unsigned long ptr;
698 LIST_HEAD(list);
699 LIST_HEAD(useless);
700 int cowonly;
701 int ret;
702 int err = 0;
703 bool need_check = true;
704
705 path1 = btrfs_alloc_path();
706 path2 = btrfs_alloc_path();
707 if (!path1 || !path2) {
708 err = -ENOMEM;
709 goto out;
710 }
711 path1->reada = 1;
712 path2->reada = 2;
713
714 node = alloc_backref_node(cache);
715 if (!node) {
716 err = -ENOMEM;
717 goto out;
718 }
719
720 node->bytenr = bytenr;
721 node->level = level;
722 node->lowest = 1;
723 cur = node;
724 again:
725 end = 0;
726 ptr = 0;
727 key.objectid = cur->bytenr;
728 key.type = BTRFS_METADATA_ITEM_KEY;
729 key.offset = (u64)-1;
730
731 path1->search_commit_root = 1;
732 path1->skip_locking = 1;
733 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
734 0, 0);
735 if (ret < 0) {
736 err = ret;
737 goto out;
738 }
739 ASSERT(ret);
740 ASSERT(path1->slots[0]);
741
742 path1->slots[0]--;
743
744 WARN_ON(cur->checked);
745 if (!list_empty(&cur->upper)) {
746 /*
747 * the backref was added previously when processing
748 * backref of type BTRFS_TREE_BLOCK_REF_KEY
749 */
750 ASSERT(list_is_singular(&cur->upper));
751 edge = list_entry(cur->upper.next, struct backref_edge,
752 list[LOWER]);
753 ASSERT(list_empty(&edge->list[UPPER]));
754 exist = edge->node[UPPER];
755 /*
756 * add the upper level block to pending list if we need
757 * check its backrefs
758 */
759 if (!exist->checked)
760 list_add_tail(&edge->list[UPPER], &list);
761 } else {
762 exist = NULL;
763 }
764
765 while (1) {
766 cond_resched();
767 eb = path1->nodes[0];
768
769 if (ptr >= end) {
770 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
771 ret = btrfs_next_leaf(rc->extent_root, path1);
772 if (ret < 0) {
773 err = ret;
774 goto out;
775 }
776 if (ret > 0)
777 break;
778 eb = path1->nodes[0];
779 }
780
781 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
782 if (key.objectid != cur->bytenr) {
783 WARN_ON(exist);
784 break;
785 }
786
787 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
788 key.type == BTRFS_METADATA_ITEM_KEY) {
789 ret = find_inline_backref(eb, path1->slots[0],
790 &ptr, &end);
791 if (ret)
792 goto next;
793 }
794 }
795
796 if (ptr < end) {
797 /* update key for inline back ref */
798 struct btrfs_extent_inline_ref *iref;
799 iref = (struct btrfs_extent_inline_ref *)ptr;
800 key.type = btrfs_extent_inline_ref_type(eb, iref);
801 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
802 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
803 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
804 }
805
806 if (exist &&
807 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
808 exist->owner == key.offset) ||
809 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
810 exist->bytenr == key.offset))) {
811 exist = NULL;
812 goto next;
813 }
814
815 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
816 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
817 key.type == BTRFS_EXTENT_REF_V0_KEY) {
818 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
819 struct btrfs_extent_ref_v0 *ref0;
820 ref0 = btrfs_item_ptr(eb, path1->slots[0],
821 struct btrfs_extent_ref_v0);
822 if (key.objectid == key.offset) {
823 root = find_tree_root(rc, eb, ref0);
824 if (root && !should_ignore_root(root))
825 cur->root = root;
826 else
827 list_add(&cur->list, &useless);
828 break;
829 }
830 if (is_cowonly_root(btrfs_ref_root_v0(eb,
831 ref0)))
832 cur->cowonly = 1;
833 }
834 #else
835 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
836 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
837 #endif
838 if (key.objectid == key.offset) {
839 /*
840 * only root blocks of reloc trees use
841 * backref of this type.
842 */
843 root = find_reloc_root(rc, cur->bytenr);
844 ASSERT(root);
845 cur->root = root;
846 break;
847 }
848
849 edge = alloc_backref_edge(cache);
850 if (!edge) {
851 err = -ENOMEM;
852 goto out;
853 }
854 rb_node = tree_search(&cache->rb_root, key.offset);
855 if (!rb_node) {
856 upper = alloc_backref_node(cache);
857 if (!upper) {
858 free_backref_edge(cache, edge);
859 err = -ENOMEM;
860 goto out;
861 }
862 upper->bytenr = key.offset;
863 upper->level = cur->level + 1;
864 /*
865 * backrefs for the upper level block isn't
866 * cached, add the block to pending list
867 */
868 list_add_tail(&edge->list[UPPER], &list);
869 } else {
870 upper = rb_entry(rb_node, struct backref_node,
871 rb_node);
872 ASSERT(upper->checked);
873 INIT_LIST_HEAD(&edge->list[UPPER]);
874 }
875 list_add_tail(&edge->list[LOWER], &cur->upper);
876 edge->node[LOWER] = cur;
877 edge->node[UPPER] = upper;
878
879 goto next;
880 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
881 goto next;
882 }
883
884 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
885 root = read_fs_root(rc->extent_root->fs_info, key.offset);
886 if (IS_ERR(root)) {
887 err = PTR_ERR(root);
888 goto out;
889 }
890
891 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
892 cur->cowonly = 1;
893
894 if (btrfs_root_level(&root->root_item) == cur->level) {
895 /* tree root */
896 ASSERT(btrfs_root_bytenr(&root->root_item) ==
897 cur->bytenr);
898 if (should_ignore_root(root))
899 list_add(&cur->list, &useless);
900 else
901 cur->root = root;
902 break;
903 }
904
905 level = cur->level + 1;
906
907 /*
908 * searching the tree to find upper level blocks
909 * reference the block.
910 */
911 path2->search_commit_root = 1;
912 path2->skip_locking = 1;
913 path2->lowest_level = level;
914 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
915 path2->lowest_level = 0;
916 if (ret < 0) {
917 err = ret;
918 goto out;
919 }
920 if (ret > 0 && path2->slots[level] > 0)
921 path2->slots[level]--;
922
923 eb = path2->nodes[level];
924 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
925 cur->bytenr);
926
927 lower = cur;
928 need_check = true;
929 for (; level < BTRFS_MAX_LEVEL; level++) {
930 if (!path2->nodes[level]) {
931 ASSERT(btrfs_root_bytenr(&root->root_item) ==
932 lower->bytenr);
933 if (should_ignore_root(root))
934 list_add(&lower->list, &useless);
935 else
936 lower->root = root;
937 break;
938 }
939
940 edge = alloc_backref_edge(cache);
941 if (!edge) {
942 err = -ENOMEM;
943 goto out;
944 }
945
946 eb = path2->nodes[level];
947 rb_node = tree_search(&cache->rb_root, eb->start);
948 if (!rb_node) {
949 upper = alloc_backref_node(cache);
950 if (!upper) {
951 free_backref_edge(cache, edge);
952 err = -ENOMEM;
953 goto out;
954 }
955 upper->bytenr = eb->start;
956 upper->owner = btrfs_header_owner(eb);
957 upper->level = lower->level + 1;
958 if (!test_bit(BTRFS_ROOT_REF_COWS,
959 &root->state))
960 upper->cowonly = 1;
961
962 /*
963 * if we know the block isn't shared
964 * we can void checking its backrefs.
965 */
966 if (btrfs_block_can_be_shared(root, eb))
967 upper->checked = 0;
968 else
969 upper->checked = 1;
970
971 /*
972 * add the block to pending list if we
973 * need check its backrefs, we only do this once
974 * while walking up a tree as we will catch
975 * anything else later on.
976 */
977 if (!upper->checked && need_check) {
978 need_check = false;
979 list_add_tail(&edge->list[UPPER],
980 &list);
981 } else {
982 if (upper->checked)
983 need_check = true;
984 INIT_LIST_HEAD(&edge->list[UPPER]);
985 }
986 } else {
987 upper = rb_entry(rb_node, struct backref_node,
988 rb_node);
989 ASSERT(upper->checked);
990 INIT_LIST_HEAD(&edge->list[UPPER]);
991 if (!upper->owner)
992 upper->owner = btrfs_header_owner(eb);
993 }
994 list_add_tail(&edge->list[LOWER], &lower->upper);
995 edge->node[LOWER] = lower;
996 edge->node[UPPER] = upper;
997
998 if (rb_node)
999 break;
1000 lower = upper;
1001 upper = NULL;
1002 }
1003 btrfs_release_path(path2);
1004 next:
1005 if (ptr < end) {
1006 ptr += btrfs_extent_inline_ref_size(key.type);
1007 if (ptr >= end) {
1008 WARN_ON(ptr > end);
1009 ptr = 0;
1010 end = 0;
1011 }
1012 }
1013 if (ptr >= end)
1014 path1->slots[0]++;
1015 }
1016 btrfs_release_path(path1);
1017
1018 cur->checked = 1;
1019 WARN_ON(exist);
1020
1021 /* the pending list isn't empty, take the first block to process */
1022 if (!list_empty(&list)) {
1023 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1024 list_del_init(&edge->list[UPPER]);
1025 cur = edge->node[UPPER];
1026 goto again;
1027 }
1028
1029 /*
1030 * everything goes well, connect backref nodes and insert backref nodes
1031 * into the cache.
1032 */
1033 ASSERT(node->checked);
1034 cowonly = node->cowonly;
1035 if (!cowonly) {
1036 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1037 &node->rb_node);
1038 if (rb_node)
1039 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1040 list_add_tail(&node->lower, &cache->leaves);
1041 }
1042
1043 list_for_each_entry(edge, &node->upper, list[LOWER])
1044 list_add_tail(&edge->list[UPPER], &list);
1045
1046 while (!list_empty(&list)) {
1047 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1048 list_del_init(&edge->list[UPPER]);
1049 upper = edge->node[UPPER];
1050 if (upper->detached) {
1051 list_del(&edge->list[LOWER]);
1052 lower = edge->node[LOWER];
1053 free_backref_edge(cache, edge);
1054 if (list_empty(&lower->upper))
1055 list_add(&lower->list, &useless);
1056 continue;
1057 }
1058
1059 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1060 if (upper->lowest) {
1061 list_del_init(&upper->lower);
1062 upper->lowest = 0;
1063 }
1064
1065 list_add_tail(&edge->list[UPPER], &upper->lower);
1066 continue;
1067 }
1068
1069 if (!upper->checked) {
1070 /*
1071 * Still want to blow up for developers since this is a
1072 * logic bug.
1073 */
1074 ASSERT(0);
1075 err = -EINVAL;
1076 goto out;
1077 }
1078 if (cowonly != upper->cowonly) {
1079 ASSERT(0);
1080 err = -EINVAL;
1081 goto out;
1082 }
1083
1084 if (!cowonly) {
1085 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1086 &upper->rb_node);
1087 if (rb_node)
1088 backref_tree_panic(rb_node, -EEXIST,
1089 upper->bytenr);
1090 }
1091
1092 list_add_tail(&edge->list[UPPER], &upper->lower);
1093
1094 list_for_each_entry(edge, &upper->upper, list[LOWER])
1095 list_add_tail(&edge->list[UPPER], &list);
1096 }
1097 /*
1098 * process useless backref nodes. backref nodes for tree leaves
1099 * are deleted from the cache. backref nodes for upper level
1100 * tree blocks are left in the cache to avoid unnecessary backref
1101 * lookup.
1102 */
1103 while (!list_empty(&useless)) {
1104 upper = list_entry(useless.next, struct backref_node, list);
1105 list_del_init(&upper->list);
1106 ASSERT(list_empty(&upper->upper));
1107 if (upper == node)
1108 node = NULL;
1109 if (upper->lowest) {
1110 list_del_init(&upper->lower);
1111 upper->lowest = 0;
1112 }
1113 while (!list_empty(&upper->lower)) {
1114 edge = list_entry(upper->lower.next,
1115 struct backref_edge, list[UPPER]);
1116 list_del(&edge->list[UPPER]);
1117 list_del(&edge->list[LOWER]);
1118 lower = edge->node[LOWER];
1119 free_backref_edge(cache, edge);
1120
1121 if (list_empty(&lower->upper))
1122 list_add(&lower->list, &useless);
1123 }
1124 __mark_block_processed(rc, upper);
1125 if (upper->level > 0) {
1126 list_add(&upper->list, &cache->detached);
1127 upper->detached = 1;
1128 } else {
1129 rb_erase(&upper->rb_node, &cache->rb_root);
1130 free_backref_node(cache, upper);
1131 }
1132 }
1133 out:
1134 btrfs_free_path(path1);
1135 btrfs_free_path(path2);
1136 if (err) {
1137 while (!list_empty(&useless)) {
1138 lower = list_entry(useless.next,
1139 struct backref_node, list);
1140 list_del_init(&lower->list);
1141 }
1142 while (!list_empty(&list)) {
1143 edge = list_first_entry(&list, struct backref_edge,
1144 list[UPPER]);
1145 list_del(&edge->list[UPPER]);
1146 list_del(&edge->list[LOWER]);
1147 lower = edge->node[LOWER];
1148 upper = edge->node[UPPER];
1149 free_backref_edge(cache, edge);
1150
1151 /*
1152 * Lower is no longer linked to any upper backref nodes
1153 * and isn't in the cache, we can free it ourselves.
1154 */
1155 if (list_empty(&lower->upper) &&
1156 RB_EMPTY_NODE(&lower->rb_node))
1157 list_add(&lower->list, &useless);
1158
1159 if (!RB_EMPTY_NODE(&upper->rb_node))
1160 continue;
1161
1162 /* Add this guy's upper edges to the list to proces */
1163 list_for_each_entry(edge, &upper->upper, list[LOWER])
1164 list_add_tail(&edge->list[UPPER], &list);
1165 if (list_empty(&upper->upper))
1166 list_add(&upper->list, &useless);
1167 }
1168
1169 while (!list_empty(&useless)) {
1170 lower = list_entry(useless.next,
1171 struct backref_node, list);
1172 list_del_init(&lower->list);
1173 free_backref_node(cache, lower);
1174 }
1175 return ERR_PTR(err);
1176 }
1177 ASSERT(!node || !node->detached);
1178 return node;
1179 }
1180
1181 /*
1182 * helper to add backref node for the newly created snapshot.
1183 * the backref node is created by cloning backref node that
1184 * corresponds to root of source tree
1185 */
1186 static int clone_backref_node(struct btrfs_trans_handle *trans,
1187 struct reloc_control *rc,
1188 struct btrfs_root *src,
1189 struct btrfs_root *dest)
1190 {
1191 struct btrfs_root *reloc_root = src->reloc_root;
1192 struct backref_cache *cache = &rc->backref_cache;
1193 struct backref_node *node = NULL;
1194 struct backref_node *new_node;
1195 struct backref_edge *edge;
1196 struct backref_edge *new_edge;
1197 struct rb_node *rb_node;
1198
1199 if (cache->last_trans > 0)
1200 update_backref_cache(trans, cache);
1201
1202 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1203 if (rb_node) {
1204 node = rb_entry(rb_node, struct backref_node, rb_node);
1205 if (node->detached)
1206 node = NULL;
1207 else
1208 BUG_ON(node->new_bytenr != reloc_root->node->start);
1209 }
1210
1211 if (!node) {
1212 rb_node = tree_search(&cache->rb_root,
1213 reloc_root->commit_root->start);
1214 if (rb_node) {
1215 node = rb_entry(rb_node, struct backref_node,
1216 rb_node);
1217 BUG_ON(node->detached);
1218 }
1219 }
1220
1221 if (!node)
1222 return 0;
1223
1224 new_node = alloc_backref_node(cache);
1225 if (!new_node)
1226 return -ENOMEM;
1227
1228 new_node->bytenr = dest->node->start;
1229 new_node->level = node->level;
1230 new_node->lowest = node->lowest;
1231 new_node->checked = 1;
1232 new_node->root = dest;
1233
1234 if (!node->lowest) {
1235 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1236 new_edge = alloc_backref_edge(cache);
1237 if (!new_edge)
1238 goto fail;
1239
1240 new_edge->node[UPPER] = new_node;
1241 new_edge->node[LOWER] = edge->node[LOWER];
1242 list_add_tail(&new_edge->list[UPPER],
1243 &new_node->lower);
1244 }
1245 } else {
1246 list_add_tail(&new_node->lower, &cache->leaves);
1247 }
1248
1249 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1250 &new_node->rb_node);
1251 if (rb_node)
1252 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1253
1254 if (!new_node->lowest) {
1255 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1256 list_add_tail(&new_edge->list[LOWER],
1257 &new_edge->node[LOWER]->upper);
1258 }
1259 }
1260 return 0;
1261 fail:
1262 while (!list_empty(&new_node->lower)) {
1263 new_edge = list_entry(new_node->lower.next,
1264 struct backref_edge, list[UPPER]);
1265 list_del(&new_edge->list[UPPER]);
1266 free_backref_edge(cache, new_edge);
1267 }
1268 free_backref_node(cache, new_node);
1269 return -ENOMEM;
1270 }
1271
1272 /*
1273 * helper to add 'address of tree root -> reloc tree' mapping
1274 */
1275 static int __must_check __add_reloc_root(struct btrfs_root *root)
1276 {
1277 struct rb_node *rb_node;
1278 struct mapping_node *node;
1279 struct reloc_control *rc = root->fs_info->reloc_ctl;
1280
1281 node = kmalloc(sizeof(*node), GFP_NOFS);
1282 if (!node)
1283 return -ENOMEM;
1284
1285 node->bytenr = root->node->start;
1286 node->data = root;
1287
1288 spin_lock(&rc->reloc_root_tree.lock);
1289 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1290 node->bytenr, &node->rb_node);
1291 spin_unlock(&rc->reloc_root_tree.lock);
1292 if (rb_node) {
1293 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1294 "for start=%llu while inserting into relocation "
1295 "tree", node->bytenr);
1296 kfree(node);
1297 return -EEXIST;
1298 }
1299
1300 list_add_tail(&root->root_list, &rc->reloc_roots);
1301 return 0;
1302 }
1303
1304 /*
1305 * helper to delete the 'address of tree root -> reloc tree'
1306 * mapping
1307 */
1308 static void __del_reloc_root(struct btrfs_root *root)
1309 {
1310 struct rb_node *rb_node;
1311 struct mapping_node *node = NULL;
1312 struct reloc_control *rc = root->fs_info->reloc_ctl;
1313
1314 spin_lock(&rc->reloc_root_tree.lock);
1315 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1316 root->node->start);
1317 if (rb_node) {
1318 node = rb_entry(rb_node, struct mapping_node, rb_node);
1319 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1320 }
1321 spin_unlock(&rc->reloc_root_tree.lock);
1322
1323 if (!node)
1324 return;
1325 BUG_ON((struct btrfs_root *)node->data != root);
1326
1327 spin_lock(&root->fs_info->trans_lock);
1328 list_del_init(&root->root_list);
1329 spin_unlock(&root->fs_info->trans_lock);
1330 kfree(node);
1331 }
1332
1333 /*
1334 * helper to update the 'address of tree root -> reloc tree'
1335 * mapping
1336 */
1337 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1338 {
1339 struct rb_node *rb_node;
1340 struct mapping_node *node = NULL;
1341 struct reloc_control *rc = root->fs_info->reloc_ctl;
1342
1343 spin_lock(&rc->reloc_root_tree.lock);
1344 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1345 root->node->start);
1346 if (rb_node) {
1347 node = rb_entry(rb_node, struct mapping_node, rb_node);
1348 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1349 }
1350 spin_unlock(&rc->reloc_root_tree.lock);
1351
1352 if (!node)
1353 return 0;
1354 BUG_ON((struct btrfs_root *)node->data != root);
1355
1356 spin_lock(&rc->reloc_root_tree.lock);
1357 node->bytenr = new_bytenr;
1358 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1359 node->bytenr, &node->rb_node);
1360 spin_unlock(&rc->reloc_root_tree.lock);
1361 if (rb_node)
1362 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1363 return 0;
1364 }
1365
1366 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1367 struct btrfs_root *root, u64 objectid)
1368 {
1369 struct btrfs_root *reloc_root;
1370 struct extent_buffer *eb;
1371 struct btrfs_root_item *root_item;
1372 struct btrfs_key root_key;
1373 u64 last_snap = 0;
1374 int ret;
1375
1376 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1377 BUG_ON(!root_item);
1378
1379 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1380 root_key.type = BTRFS_ROOT_ITEM_KEY;
1381 root_key.offset = objectid;
1382
1383 if (root->root_key.objectid == objectid) {
1384 /* called by btrfs_init_reloc_root */
1385 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1386 BTRFS_TREE_RELOC_OBJECTID);
1387 BUG_ON(ret);
1388
1389 last_snap = btrfs_root_last_snapshot(&root->root_item);
1390 btrfs_set_root_last_snapshot(&root->root_item,
1391 trans->transid - 1);
1392 } else {
1393 /*
1394 * called by btrfs_reloc_post_snapshot_hook.
1395 * the source tree is a reloc tree, all tree blocks
1396 * modified after it was created have RELOC flag
1397 * set in their headers. so it's OK to not update
1398 * the 'last_snapshot'.
1399 */
1400 ret = btrfs_copy_root(trans, root, root->node, &eb,
1401 BTRFS_TREE_RELOC_OBJECTID);
1402 BUG_ON(ret);
1403 }
1404
1405 memcpy(root_item, &root->root_item, sizeof(*root_item));
1406 btrfs_set_root_bytenr(root_item, eb->start);
1407 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1408 btrfs_set_root_generation(root_item, trans->transid);
1409
1410 if (root->root_key.objectid == objectid) {
1411 btrfs_set_root_refs(root_item, 0);
1412 memset(&root_item->drop_progress, 0,
1413 sizeof(struct btrfs_disk_key));
1414 root_item->drop_level = 0;
1415 /*
1416 * abuse rtransid, it is safe because it is impossible to
1417 * receive data into a relocation tree.
1418 */
1419 btrfs_set_root_rtransid(root_item, last_snap);
1420 btrfs_set_root_otransid(root_item, trans->transid);
1421 }
1422
1423 btrfs_tree_unlock(eb);
1424 free_extent_buffer(eb);
1425
1426 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1427 &root_key, root_item);
1428 BUG_ON(ret);
1429 kfree(root_item);
1430
1431 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1432 BUG_ON(IS_ERR(reloc_root));
1433 reloc_root->last_trans = trans->transid;
1434 return reloc_root;
1435 }
1436
1437 /*
1438 * create reloc tree for a given fs tree. reloc tree is just a
1439 * snapshot of the fs tree with special root objectid.
1440 */
1441 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1442 struct btrfs_root *root)
1443 {
1444 struct btrfs_root *reloc_root;
1445 struct reloc_control *rc = root->fs_info->reloc_ctl;
1446 struct btrfs_block_rsv *rsv;
1447 int clear_rsv = 0;
1448 int ret;
1449
1450 if (root->reloc_root) {
1451 reloc_root = root->reloc_root;
1452 reloc_root->last_trans = trans->transid;
1453 return 0;
1454 }
1455
1456 if (!rc || !rc->create_reloc_tree ||
1457 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1458 return 0;
1459
1460 if (!trans->reloc_reserved) {
1461 rsv = trans->block_rsv;
1462 trans->block_rsv = rc->block_rsv;
1463 clear_rsv = 1;
1464 }
1465 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1466 if (clear_rsv)
1467 trans->block_rsv = rsv;
1468
1469 ret = __add_reloc_root(reloc_root);
1470 BUG_ON(ret < 0);
1471 root->reloc_root = reloc_root;
1472 return 0;
1473 }
1474
1475 /*
1476 * update root item of reloc tree
1477 */
1478 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1479 struct btrfs_root *root)
1480 {
1481 struct btrfs_root *reloc_root;
1482 struct btrfs_root_item *root_item;
1483 int ret;
1484
1485 if (!root->reloc_root)
1486 goto out;
1487
1488 reloc_root = root->reloc_root;
1489 root_item = &reloc_root->root_item;
1490
1491 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1492 btrfs_root_refs(root_item) == 0) {
1493 root->reloc_root = NULL;
1494 __del_reloc_root(reloc_root);
1495 }
1496
1497 if (reloc_root->commit_root != reloc_root->node) {
1498 btrfs_set_root_node(root_item, reloc_root->node);
1499 free_extent_buffer(reloc_root->commit_root);
1500 reloc_root->commit_root = btrfs_root_node(reloc_root);
1501 }
1502
1503 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1504 &reloc_root->root_key, root_item);
1505 BUG_ON(ret);
1506
1507 out:
1508 return 0;
1509 }
1510
1511 /*
1512 * helper to find first cached inode with inode number >= objectid
1513 * in a subvolume
1514 */
1515 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1516 {
1517 struct rb_node *node;
1518 struct rb_node *prev;
1519 struct btrfs_inode *entry;
1520 struct inode *inode;
1521
1522 spin_lock(&root->inode_lock);
1523 again:
1524 node = root->inode_tree.rb_node;
1525 prev = NULL;
1526 while (node) {
1527 prev = node;
1528 entry = rb_entry(node, struct btrfs_inode, rb_node);
1529
1530 if (objectid < btrfs_ino(&entry->vfs_inode))
1531 node = node->rb_left;
1532 else if (objectid > btrfs_ino(&entry->vfs_inode))
1533 node = node->rb_right;
1534 else
1535 break;
1536 }
1537 if (!node) {
1538 while (prev) {
1539 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1540 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1541 node = prev;
1542 break;
1543 }
1544 prev = rb_next(prev);
1545 }
1546 }
1547 while (node) {
1548 entry = rb_entry(node, struct btrfs_inode, rb_node);
1549 inode = igrab(&entry->vfs_inode);
1550 if (inode) {
1551 spin_unlock(&root->inode_lock);
1552 return inode;
1553 }
1554
1555 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1556 if (cond_resched_lock(&root->inode_lock))
1557 goto again;
1558
1559 node = rb_next(node);
1560 }
1561 spin_unlock(&root->inode_lock);
1562 return NULL;
1563 }
1564
1565 static int in_block_group(u64 bytenr,
1566 struct btrfs_block_group_cache *block_group)
1567 {
1568 if (bytenr >= block_group->key.objectid &&
1569 bytenr < block_group->key.objectid + block_group->key.offset)
1570 return 1;
1571 return 0;
1572 }
1573
1574 /*
1575 * get new location of data
1576 */
1577 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1578 u64 bytenr, u64 num_bytes)
1579 {
1580 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1581 struct btrfs_path *path;
1582 struct btrfs_file_extent_item *fi;
1583 struct extent_buffer *leaf;
1584 int ret;
1585
1586 path = btrfs_alloc_path();
1587 if (!path)
1588 return -ENOMEM;
1589
1590 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1591 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1592 bytenr, 0);
1593 if (ret < 0)
1594 goto out;
1595 if (ret > 0) {
1596 ret = -ENOENT;
1597 goto out;
1598 }
1599
1600 leaf = path->nodes[0];
1601 fi = btrfs_item_ptr(leaf, path->slots[0],
1602 struct btrfs_file_extent_item);
1603
1604 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1605 btrfs_file_extent_compression(leaf, fi) ||
1606 btrfs_file_extent_encryption(leaf, fi) ||
1607 btrfs_file_extent_other_encoding(leaf, fi));
1608
1609 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1610 ret = -EINVAL;
1611 goto out;
1612 }
1613
1614 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1615 ret = 0;
1616 out:
1617 btrfs_free_path(path);
1618 return ret;
1619 }
1620
1621 /*
1622 * update file extent items in the tree leaf to point to
1623 * the new locations.
1624 */
1625 static noinline_for_stack
1626 int replace_file_extents(struct btrfs_trans_handle *trans,
1627 struct reloc_control *rc,
1628 struct btrfs_root *root,
1629 struct extent_buffer *leaf)
1630 {
1631 struct btrfs_key key;
1632 struct btrfs_file_extent_item *fi;
1633 struct inode *inode = NULL;
1634 u64 parent;
1635 u64 bytenr;
1636 u64 new_bytenr = 0;
1637 u64 num_bytes;
1638 u64 end;
1639 u32 nritems;
1640 u32 i;
1641 int ret = 0;
1642 int first = 1;
1643 int dirty = 0;
1644
1645 if (rc->stage != UPDATE_DATA_PTRS)
1646 return 0;
1647
1648 /* reloc trees always use full backref */
1649 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1650 parent = leaf->start;
1651 else
1652 parent = 0;
1653
1654 nritems = btrfs_header_nritems(leaf);
1655 for (i = 0; i < nritems; i++) {
1656 cond_resched();
1657 btrfs_item_key_to_cpu(leaf, &key, i);
1658 if (key.type != BTRFS_EXTENT_DATA_KEY)
1659 continue;
1660 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1661 if (btrfs_file_extent_type(leaf, fi) ==
1662 BTRFS_FILE_EXTENT_INLINE)
1663 continue;
1664 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1665 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1666 if (bytenr == 0)
1667 continue;
1668 if (!in_block_group(bytenr, rc->block_group))
1669 continue;
1670
1671 /*
1672 * if we are modifying block in fs tree, wait for readpage
1673 * to complete and drop the extent cache
1674 */
1675 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1676 if (first) {
1677 inode = find_next_inode(root, key.objectid);
1678 first = 0;
1679 } else if (inode && btrfs_ino(inode) < key.objectid) {
1680 btrfs_add_delayed_iput(inode);
1681 inode = find_next_inode(root, key.objectid);
1682 }
1683 if (inode && btrfs_ino(inode) == key.objectid) {
1684 end = key.offset +
1685 btrfs_file_extent_num_bytes(leaf, fi);
1686 WARN_ON(!IS_ALIGNED(key.offset,
1687 root->sectorsize));
1688 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1689 end--;
1690 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1691 key.offset, end);
1692 if (!ret)
1693 continue;
1694
1695 btrfs_drop_extent_cache(inode, key.offset, end,
1696 1);
1697 unlock_extent(&BTRFS_I(inode)->io_tree,
1698 key.offset, end);
1699 }
1700 }
1701
1702 ret = get_new_location(rc->data_inode, &new_bytenr,
1703 bytenr, num_bytes);
1704 if (ret) {
1705 /*
1706 * Don't have to abort since we've not changed anything
1707 * in the file extent yet.
1708 */
1709 break;
1710 }
1711
1712 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1713 dirty = 1;
1714
1715 key.offset -= btrfs_file_extent_offset(leaf, fi);
1716 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1717 num_bytes, parent,
1718 btrfs_header_owner(leaf),
1719 key.objectid, key.offset, 1);
1720 if (ret) {
1721 btrfs_abort_transaction(trans, root, ret);
1722 break;
1723 }
1724
1725 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1726 parent, btrfs_header_owner(leaf),
1727 key.objectid, key.offset, 1);
1728 if (ret) {
1729 btrfs_abort_transaction(trans, root, ret);
1730 break;
1731 }
1732 }
1733 if (dirty)
1734 btrfs_mark_buffer_dirty(leaf);
1735 if (inode)
1736 btrfs_add_delayed_iput(inode);
1737 return ret;
1738 }
1739
1740 static noinline_for_stack
1741 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1742 struct btrfs_path *path, int level)
1743 {
1744 struct btrfs_disk_key key1;
1745 struct btrfs_disk_key key2;
1746 btrfs_node_key(eb, &key1, slot);
1747 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1748 return memcmp(&key1, &key2, sizeof(key1));
1749 }
1750
1751 /*
1752 * try to replace tree blocks in fs tree with the new blocks
1753 * in reloc tree. tree blocks haven't been modified since the
1754 * reloc tree was create can be replaced.
1755 *
1756 * if a block was replaced, level of the block + 1 is returned.
1757 * if no block got replaced, 0 is returned. if there are other
1758 * errors, a negative error number is returned.
1759 */
1760 static noinline_for_stack
1761 int replace_path(struct btrfs_trans_handle *trans,
1762 struct btrfs_root *dest, struct btrfs_root *src,
1763 struct btrfs_path *path, struct btrfs_key *next_key,
1764 int lowest_level, int max_level)
1765 {
1766 struct extent_buffer *eb;
1767 struct extent_buffer *parent;
1768 struct btrfs_key key;
1769 u64 old_bytenr;
1770 u64 new_bytenr;
1771 u64 old_ptr_gen;
1772 u64 new_ptr_gen;
1773 u64 last_snapshot;
1774 u32 blocksize;
1775 int cow = 0;
1776 int level;
1777 int ret;
1778 int slot;
1779
1780 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1781 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1782
1783 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1784 again:
1785 slot = path->slots[lowest_level];
1786 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1787
1788 eb = btrfs_lock_root_node(dest);
1789 btrfs_set_lock_blocking(eb);
1790 level = btrfs_header_level(eb);
1791
1792 if (level < lowest_level) {
1793 btrfs_tree_unlock(eb);
1794 free_extent_buffer(eb);
1795 return 0;
1796 }
1797
1798 if (cow) {
1799 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1800 BUG_ON(ret);
1801 }
1802 btrfs_set_lock_blocking(eb);
1803
1804 if (next_key) {
1805 next_key->objectid = (u64)-1;
1806 next_key->type = (u8)-1;
1807 next_key->offset = (u64)-1;
1808 }
1809
1810 parent = eb;
1811 while (1) {
1812 level = btrfs_header_level(parent);
1813 BUG_ON(level < lowest_level);
1814
1815 ret = btrfs_bin_search(parent, &key, level, &slot);
1816 if (ret && slot > 0)
1817 slot--;
1818
1819 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1820 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1821
1822 old_bytenr = btrfs_node_blockptr(parent, slot);
1823 blocksize = dest->nodesize;
1824 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1825
1826 if (level <= max_level) {
1827 eb = path->nodes[level];
1828 new_bytenr = btrfs_node_blockptr(eb,
1829 path->slots[level]);
1830 new_ptr_gen = btrfs_node_ptr_generation(eb,
1831 path->slots[level]);
1832 } else {
1833 new_bytenr = 0;
1834 new_ptr_gen = 0;
1835 }
1836
1837 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1838 ret = level;
1839 break;
1840 }
1841
1842 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1843 memcmp_node_keys(parent, slot, path, level)) {
1844 if (level <= lowest_level) {
1845 ret = 0;
1846 break;
1847 }
1848
1849 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1850 if (!eb || !extent_buffer_uptodate(eb)) {
1851 ret = (!eb) ? -ENOMEM : -EIO;
1852 free_extent_buffer(eb);
1853 break;
1854 }
1855 btrfs_tree_lock(eb);
1856 if (cow) {
1857 ret = btrfs_cow_block(trans, dest, eb, parent,
1858 slot, &eb);
1859 BUG_ON(ret);
1860 }
1861 btrfs_set_lock_blocking(eb);
1862
1863 btrfs_tree_unlock(parent);
1864 free_extent_buffer(parent);
1865
1866 parent = eb;
1867 continue;
1868 }
1869
1870 if (!cow) {
1871 btrfs_tree_unlock(parent);
1872 free_extent_buffer(parent);
1873 cow = 1;
1874 goto again;
1875 }
1876
1877 btrfs_node_key_to_cpu(path->nodes[level], &key,
1878 path->slots[level]);
1879 btrfs_release_path(path);
1880
1881 path->lowest_level = level;
1882 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1883 path->lowest_level = 0;
1884 BUG_ON(ret);
1885
1886 /*
1887 * swap blocks in fs tree and reloc tree.
1888 */
1889 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1890 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1891 btrfs_mark_buffer_dirty(parent);
1892
1893 btrfs_set_node_blockptr(path->nodes[level],
1894 path->slots[level], old_bytenr);
1895 btrfs_set_node_ptr_generation(path->nodes[level],
1896 path->slots[level], old_ptr_gen);
1897 btrfs_mark_buffer_dirty(path->nodes[level]);
1898
1899 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1900 path->nodes[level]->start,
1901 src->root_key.objectid, level - 1, 0,
1902 1);
1903 BUG_ON(ret);
1904 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1905 0, dest->root_key.objectid, level - 1,
1906 0, 1);
1907 BUG_ON(ret);
1908
1909 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1910 path->nodes[level]->start,
1911 src->root_key.objectid, level - 1, 0,
1912 1);
1913 BUG_ON(ret);
1914
1915 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1916 0, dest->root_key.objectid, level - 1,
1917 0, 1);
1918 BUG_ON(ret);
1919
1920 btrfs_unlock_up_safe(path, 0);
1921
1922 ret = level;
1923 break;
1924 }
1925 btrfs_tree_unlock(parent);
1926 free_extent_buffer(parent);
1927 return ret;
1928 }
1929
1930 /*
1931 * helper to find next relocated block in reloc tree
1932 */
1933 static noinline_for_stack
1934 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1935 int *level)
1936 {
1937 struct extent_buffer *eb;
1938 int i;
1939 u64 last_snapshot;
1940 u32 nritems;
1941
1942 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1943
1944 for (i = 0; i < *level; i++) {
1945 free_extent_buffer(path->nodes[i]);
1946 path->nodes[i] = NULL;
1947 }
1948
1949 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1950 eb = path->nodes[i];
1951 nritems = btrfs_header_nritems(eb);
1952 while (path->slots[i] + 1 < nritems) {
1953 path->slots[i]++;
1954 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1955 last_snapshot)
1956 continue;
1957
1958 *level = i;
1959 return 0;
1960 }
1961 free_extent_buffer(path->nodes[i]);
1962 path->nodes[i] = NULL;
1963 }
1964 return 1;
1965 }
1966
1967 /*
1968 * walk down reloc tree to find relocated block of lowest level
1969 */
1970 static noinline_for_stack
1971 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1972 int *level)
1973 {
1974 struct extent_buffer *eb = NULL;
1975 int i;
1976 u64 bytenr;
1977 u64 ptr_gen = 0;
1978 u64 last_snapshot;
1979 u32 nritems;
1980
1981 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1982
1983 for (i = *level; i > 0; i--) {
1984 eb = path->nodes[i];
1985 nritems = btrfs_header_nritems(eb);
1986 while (path->slots[i] < nritems) {
1987 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1988 if (ptr_gen > last_snapshot)
1989 break;
1990 path->slots[i]++;
1991 }
1992 if (path->slots[i] >= nritems) {
1993 if (i == *level)
1994 break;
1995 *level = i + 1;
1996 return 0;
1997 }
1998 if (i == 1) {
1999 *level = i;
2000 return 0;
2001 }
2002
2003 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2004 eb = read_tree_block(root, bytenr, ptr_gen);
2005 if (!eb || !extent_buffer_uptodate(eb)) {
2006 free_extent_buffer(eb);
2007 return -EIO;
2008 }
2009 BUG_ON(btrfs_header_level(eb) != i - 1);
2010 path->nodes[i - 1] = eb;
2011 path->slots[i - 1] = 0;
2012 }
2013 return 1;
2014 }
2015
2016 /*
2017 * invalidate extent cache for file extents whose key in range of
2018 * [min_key, max_key)
2019 */
2020 static int invalidate_extent_cache(struct btrfs_root *root,
2021 struct btrfs_key *min_key,
2022 struct btrfs_key *max_key)
2023 {
2024 struct inode *inode = NULL;
2025 u64 objectid;
2026 u64 start, end;
2027 u64 ino;
2028
2029 objectid = min_key->objectid;
2030 while (1) {
2031 cond_resched();
2032 iput(inode);
2033
2034 if (objectid > max_key->objectid)
2035 break;
2036
2037 inode = find_next_inode(root, objectid);
2038 if (!inode)
2039 break;
2040 ino = btrfs_ino(inode);
2041
2042 if (ino > max_key->objectid) {
2043 iput(inode);
2044 break;
2045 }
2046
2047 objectid = ino + 1;
2048 if (!S_ISREG(inode->i_mode))
2049 continue;
2050
2051 if (unlikely(min_key->objectid == ino)) {
2052 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2053 continue;
2054 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2055 start = 0;
2056 else {
2057 start = min_key->offset;
2058 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2059 }
2060 } else {
2061 start = 0;
2062 }
2063
2064 if (unlikely(max_key->objectid == ino)) {
2065 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2066 continue;
2067 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2068 end = (u64)-1;
2069 } else {
2070 if (max_key->offset == 0)
2071 continue;
2072 end = max_key->offset;
2073 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2074 end--;
2075 }
2076 } else {
2077 end = (u64)-1;
2078 }
2079
2080 /* the lock_extent waits for readpage to complete */
2081 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2082 btrfs_drop_extent_cache(inode, start, end, 1);
2083 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2084 }
2085 return 0;
2086 }
2087
2088 static int find_next_key(struct btrfs_path *path, int level,
2089 struct btrfs_key *key)
2090
2091 {
2092 while (level < BTRFS_MAX_LEVEL) {
2093 if (!path->nodes[level])
2094 break;
2095 if (path->slots[level] + 1 <
2096 btrfs_header_nritems(path->nodes[level])) {
2097 btrfs_node_key_to_cpu(path->nodes[level], key,
2098 path->slots[level] + 1);
2099 return 0;
2100 }
2101 level++;
2102 }
2103 return 1;
2104 }
2105
2106 /*
2107 * merge the relocated tree blocks in reloc tree with corresponding
2108 * fs tree.
2109 */
2110 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2111 struct btrfs_root *root)
2112 {
2113 LIST_HEAD(inode_list);
2114 struct btrfs_key key;
2115 struct btrfs_key next_key;
2116 struct btrfs_trans_handle *trans = NULL;
2117 struct btrfs_root *reloc_root;
2118 struct btrfs_root_item *root_item;
2119 struct btrfs_path *path;
2120 struct extent_buffer *leaf;
2121 int level;
2122 int max_level;
2123 int replaced = 0;
2124 int ret;
2125 int err = 0;
2126 u32 min_reserved;
2127
2128 path = btrfs_alloc_path();
2129 if (!path)
2130 return -ENOMEM;
2131 path->reada = 1;
2132
2133 reloc_root = root->reloc_root;
2134 root_item = &reloc_root->root_item;
2135
2136 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2137 level = btrfs_root_level(root_item);
2138 extent_buffer_get(reloc_root->node);
2139 path->nodes[level] = reloc_root->node;
2140 path->slots[level] = 0;
2141 } else {
2142 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2143
2144 level = root_item->drop_level;
2145 BUG_ON(level == 0);
2146 path->lowest_level = level;
2147 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2148 path->lowest_level = 0;
2149 if (ret < 0) {
2150 btrfs_free_path(path);
2151 return ret;
2152 }
2153
2154 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2155 path->slots[level]);
2156 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2157
2158 btrfs_unlock_up_safe(path, 0);
2159 }
2160
2161 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2162 memset(&next_key, 0, sizeof(next_key));
2163
2164 while (1) {
2165 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2166 BTRFS_RESERVE_FLUSH_ALL);
2167 if (ret) {
2168 err = ret;
2169 goto out;
2170 }
2171 trans = btrfs_start_transaction(root, 0);
2172 if (IS_ERR(trans)) {
2173 err = PTR_ERR(trans);
2174 trans = NULL;
2175 goto out;
2176 }
2177 trans->block_rsv = rc->block_rsv;
2178
2179 replaced = 0;
2180 max_level = level;
2181
2182 ret = walk_down_reloc_tree(reloc_root, path, &level);
2183 if (ret < 0) {
2184 err = ret;
2185 goto out;
2186 }
2187 if (ret > 0)
2188 break;
2189
2190 if (!find_next_key(path, level, &key) &&
2191 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2192 ret = 0;
2193 } else {
2194 ret = replace_path(trans, root, reloc_root, path,
2195 &next_key, level, max_level);
2196 }
2197 if (ret < 0) {
2198 err = ret;
2199 goto out;
2200 }
2201
2202 if (ret > 0) {
2203 level = ret;
2204 btrfs_node_key_to_cpu(path->nodes[level], &key,
2205 path->slots[level]);
2206 replaced = 1;
2207 }
2208
2209 ret = walk_up_reloc_tree(reloc_root, path, &level);
2210 if (ret > 0)
2211 break;
2212
2213 BUG_ON(level == 0);
2214 /*
2215 * save the merging progress in the drop_progress.
2216 * this is OK since root refs == 1 in this case.
2217 */
2218 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2219 path->slots[level]);
2220 root_item->drop_level = level;
2221
2222 btrfs_end_transaction_throttle(trans, root);
2223 trans = NULL;
2224
2225 btrfs_btree_balance_dirty(root);
2226
2227 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2228 invalidate_extent_cache(root, &key, &next_key);
2229 }
2230
2231 /*
2232 * handle the case only one block in the fs tree need to be
2233 * relocated and the block is tree root.
2234 */
2235 leaf = btrfs_lock_root_node(root);
2236 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2237 btrfs_tree_unlock(leaf);
2238 free_extent_buffer(leaf);
2239 if (ret < 0)
2240 err = ret;
2241 out:
2242 btrfs_free_path(path);
2243
2244 if (err == 0) {
2245 memset(&root_item->drop_progress, 0,
2246 sizeof(root_item->drop_progress));
2247 root_item->drop_level = 0;
2248 btrfs_set_root_refs(root_item, 0);
2249 btrfs_update_reloc_root(trans, root);
2250 }
2251
2252 if (trans)
2253 btrfs_end_transaction_throttle(trans, root);
2254
2255 btrfs_btree_balance_dirty(root);
2256
2257 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2258 invalidate_extent_cache(root, &key, &next_key);
2259
2260 return err;
2261 }
2262
2263 static noinline_for_stack
2264 int prepare_to_merge(struct reloc_control *rc, int err)
2265 {
2266 struct btrfs_root *root = rc->extent_root;
2267 struct btrfs_root *reloc_root;
2268 struct btrfs_trans_handle *trans;
2269 LIST_HEAD(reloc_roots);
2270 u64 num_bytes = 0;
2271 int ret;
2272
2273 mutex_lock(&root->fs_info->reloc_mutex);
2274 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2275 rc->merging_rsv_size += rc->nodes_relocated * 2;
2276 mutex_unlock(&root->fs_info->reloc_mutex);
2277
2278 again:
2279 if (!err) {
2280 num_bytes = rc->merging_rsv_size;
2281 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2282 BTRFS_RESERVE_FLUSH_ALL);
2283 if (ret)
2284 err = ret;
2285 }
2286
2287 trans = btrfs_join_transaction(rc->extent_root);
2288 if (IS_ERR(trans)) {
2289 if (!err)
2290 btrfs_block_rsv_release(rc->extent_root,
2291 rc->block_rsv, num_bytes);
2292 return PTR_ERR(trans);
2293 }
2294
2295 if (!err) {
2296 if (num_bytes != rc->merging_rsv_size) {
2297 btrfs_end_transaction(trans, rc->extent_root);
2298 btrfs_block_rsv_release(rc->extent_root,
2299 rc->block_rsv, num_bytes);
2300 goto again;
2301 }
2302 }
2303
2304 rc->merge_reloc_tree = 1;
2305
2306 while (!list_empty(&rc->reloc_roots)) {
2307 reloc_root = list_entry(rc->reloc_roots.next,
2308 struct btrfs_root, root_list);
2309 list_del_init(&reloc_root->root_list);
2310
2311 root = read_fs_root(reloc_root->fs_info,
2312 reloc_root->root_key.offset);
2313 BUG_ON(IS_ERR(root));
2314 BUG_ON(root->reloc_root != reloc_root);
2315
2316 /*
2317 * set reference count to 1, so btrfs_recover_relocation
2318 * knows it should resumes merging
2319 */
2320 if (!err)
2321 btrfs_set_root_refs(&reloc_root->root_item, 1);
2322 btrfs_update_reloc_root(trans, root);
2323
2324 list_add(&reloc_root->root_list, &reloc_roots);
2325 }
2326
2327 list_splice(&reloc_roots, &rc->reloc_roots);
2328
2329 if (!err)
2330 btrfs_commit_transaction(trans, rc->extent_root);
2331 else
2332 btrfs_end_transaction(trans, rc->extent_root);
2333 return err;
2334 }
2335
2336 static noinline_for_stack
2337 void free_reloc_roots(struct list_head *list)
2338 {
2339 struct btrfs_root *reloc_root;
2340
2341 while (!list_empty(list)) {
2342 reloc_root = list_entry(list->next, struct btrfs_root,
2343 root_list);
2344 __del_reloc_root(reloc_root);
2345 }
2346 }
2347
2348 static noinline_for_stack
2349 void merge_reloc_roots(struct reloc_control *rc)
2350 {
2351 struct btrfs_root *root;
2352 struct btrfs_root *reloc_root;
2353 u64 last_snap;
2354 u64 otransid;
2355 u64 objectid;
2356 LIST_HEAD(reloc_roots);
2357 int found = 0;
2358 int ret = 0;
2359 again:
2360 root = rc->extent_root;
2361
2362 /*
2363 * this serializes us with btrfs_record_root_in_transaction,
2364 * we have to make sure nobody is in the middle of
2365 * adding their roots to the list while we are
2366 * doing this splice
2367 */
2368 mutex_lock(&root->fs_info->reloc_mutex);
2369 list_splice_init(&rc->reloc_roots, &reloc_roots);
2370 mutex_unlock(&root->fs_info->reloc_mutex);
2371
2372 while (!list_empty(&reloc_roots)) {
2373 found = 1;
2374 reloc_root = list_entry(reloc_roots.next,
2375 struct btrfs_root, root_list);
2376
2377 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2378 root = read_fs_root(reloc_root->fs_info,
2379 reloc_root->root_key.offset);
2380 BUG_ON(IS_ERR(root));
2381 BUG_ON(root->reloc_root != reloc_root);
2382
2383 ret = merge_reloc_root(rc, root);
2384 if (ret) {
2385 if (list_empty(&reloc_root->root_list))
2386 list_add_tail(&reloc_root->root_list,
2387 &reloc_roots);
2388 goto out;
2389 }
2390 } else {
2391 list_del_init(&reloc_root->root_list);
2392 }
2393
2394 /*
2395 * we keep the old last snapshod transid in rtranid when we
2396 * created the relocation tree.
2397 */
2398 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2399 otransid = btrfs_root_otransid(&reloc_root->root_item);
2400 objectid = reloc_root->root_key.offset;
2401
2402 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2403 if (ret < 0) {
2404 if (list_empty(&reloc_root->root_list))
2405 list_add_tail(&reloc_root->root_list,
2406 &reloc_roots);
2407 goto out;
2408 }
2409 }
2410
2411 if (found) {
2412 found = 0;
2413 goto again;
2414 }
2415 out:
2416 if (ret) {
2417 btrfs_std_error(root->fs_info, ret);
2418 if (!list_empty(&reloc_roots))
2419 free_reloc_roots(&reloc_roots);
2420
2421 /* new reloc root may be added */
2422 mutex_lock(&root->fs_info->reloc_mutex);
2423 list_splice_init(&rc->reloc_roots, &reloc_roots);
2424 mutex_unlock(&root->fs_info->reloc_mutex);
2425 if (!list_empty(&reloc_roots))
2426 free_reloc_roots(&reloc_roots);
2427 }
2428
2429 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2430 }
2431
2432 static void free_block_list(struct rb_root *blocks)
2433 {
2434 struct tree_block *block;
2435 struct rb_node *rb_node;
2436 while ((rb_node = rb_first(blocks))) {
2437 block = rb_entry(rb_node, struct tree_block, rb_node);
2438 rb_erase(rb_node, blocks);
2439 kfree(block);
2440 }
2441 }
2442
2443 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2444 struct btrfs_root *reloc_root)
2445 {
2446 struct btrfs_root *root;
2447
2448 if (reloc_root->last_trans == trans->transid)
2449 return 0;
2450
2451 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2452 BUG_ON(IS_ERR(root));
2453 BUG_ON(root->reloc_root != reloc_root);
2454
2455 return btrfs_record_root_in_trans(trans, root);
2456 }
2457
2458 static noinline_for_stack
2459 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2460 struct reloc_control *rc,
2461 struct backref_node *node,
2462 struct backref_edge *edges[])
2463 {
2464 struct backref_node *next;
2465 struct btrfs_root *root;
2466 int index = 0;
2467
2468 next = node;
2469 while (1) {
2470 cond_resched();
2471 next = walk_up_backref(next, edges, &index);
2472 root = next->root;
2473 BUG_ON(!root);
2474 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2475
2476 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2477 record_reloc_root_in_trans(trans, root);
2478 break;
2479 }
2480
2481 btrfs_record_root_in_trans(trans, root);
2482 root = root->reloc_root;
2483
2484 if (next->new_bytenr != root->node->start) {
2485 BUG_ON(next->new_bytenr);
2486 BUG_ON(!list_empty(&next->list));
2487 next->new_bytenr = root->node->start;
2488 next->root = root;
2489 list_add_tail(&next->list,
2490 &rc->backref_cache.changed);
2491 __mark_block_processed(rc, next);
2492 break;
2493 }
2494
2495 WARN_ON(1);
2496 root = NULL;
2497 next = walk_down_backref(edges, &index);
2498 if (!next || next->level <= node->level)
2499 break;
2500 }
2501 if (!root)
2502 return NULL;
2503
2504 next = node;
2505 /* setup backref node path for btrfs_reloc_cow_block */
2506 while (1) {
2507 rc->backref_cache.path[next->level] = next;
2508 if (--index < 0)
2509 break;
2510 next = edges[index]->node[UPPER];
2511 }
2512 return root;
2513 }
2514
2515 /*
2516 * select a tree root for relocation. return NULL if the block
2517 * is reference counted. we should use do_relocation() in this
2518 * case. return a tree root pointer if the block isn't reference
2519 * counted. return -ENOENT if the block is root of reloc tree.
2520 */
2521 static noinline_for_stack
2522 struct btrfs_root *select_one_root(struct btrfs_trans_handle *trans,
2523 struct backref_node *node)
2524 {
2525 struct backref_node *next;
2526 struct btrfs_root *root;
2527 struct btrfs_root *fs_root = NULL;
2528 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2529 int index = 0;
2530
2531 next = node;
2532 while (1) {
2533 cond_resched();
2534 next = walk_up_backref(next, edges, &index);
2535 root = next->root;
2536 BUG_ON(!root);
2537
2538 /* no other choice for non-references counted tree */
2539 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2540 return root;
2541
2542 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2543 fs_root = root;
2544
2545 if (next != node)
2546 return NULL;
2547
2548 next = walk_down_backref(edges, &index);
2549 if (!next || next->level <= node->level)
2550 break;
2551 }
2552
2553 if (!fs_root)
2554 return ERR_PTR(-ENOENT);
2555 return fs_root;
2556 }
2557
2558 static noinline_for_stack
2559 u64 calcu_metadata_size(struct reloc_control *rc,
2560 struct backref_node *node, int reserve)
2561 {
2562 struct backref_node *next = node;
2563 struct backref_edge *edge;
2564 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2565 u64 num_bytes = 0;
2566 int index = 0;
2567
2568 BUG_ON(reserve && node->processed);
2569
2570 while (next) {
2571 cond_resched();
2572 while (1) {
2573 if (next->processed && (reserve || next != node))
2574 break;
2575
2576 num_bytes += rc->extent_root->nodesize;
2577
2578 if (list_empty(&next->upper))
2579 break;
2580
2581 edge = list_entry(next->upper.next,
2582 struct backref_edge, list[LOWER]);
2583 edges[index++] = edge;
2584 next = edge->node[UPPER];
2585 }
2586 next = walk_down_backref(edges, &index);
2587 }
2588 return num_bytes;
2589 }
2590
2591 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2592 struct reloc_control *rc,
2593 struct backref_node *node)
2594 {
2595 struct btrfs_root *root = rc->extent_root;
2596 u64 num_bytes;
2597 int ret;
2598 u64 tmp;
2599
2600 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2601
2602 trans->block_rsv = rc->block_rsv;
2603 rc->reserved_bytes += num_bytes;
2604 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2605 BTRFS_RESERVE_FLUSH_ALL);
2606 if (ret) {
2607 if (ret == -EAGAIN) {
2608 tmp = rc->extent_root->nodesize *
2609 RELOCATION_RESERVED_NODES;
2610 while (tmp <= rc->reserved_bytes)
2611 tmp <<= 1;
2612 /*
2613 * only one thread can access block_rsv at this point,
2614 * so we don't need hold lock to protect block_rsv.
2615 * we expand more reservation size here to allow enough
2616 * space for relocation and we will return eailer in
2617 * enospc case.
2618 */
2619 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2620 RELOCATION_RESERVED_NODES;
2621 }
2622 return ret;
2623 }
2624
2625 return 0;
2626 }
2627
2628 /*
2629 * relocate a block tree, and then update pointers in upper level
2630 * blocks that reference the block to point to the new location.
2631 *
2632 * if called by link_to_upper, the block has already been relocated.
2633 * in that case this function just updates pointers.
2634 */
2635 static int do_relocation(struct btrfs_trans_handle *trans,
2636 struct reloc_control *rc,
2637 struct backref_node *node,
2638 struct btrfs_key *key,
2639 struct btrfs_path *path, int lowest)
2640 {
2641 struct backref_node *upper;
2642 struct backref_edge *edge;
2643 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2644 struct btrfs_root *root;
2645 struct extent_buffer *eb;
2646 u32 blocksize;
2647 u64 bytenr;
2648 u64 generation;
2649 int slot;
2650 int ret;
2651 int err = 0;
2652
2653 BUG_ON(lowest && node->eb);
2654
2655 path->lowest_level = node->level + 1;
2656 rc->backref_cache.path[node->level] = node;
2657 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2658 cond_resched();
2659
2660 upper = edge->node[UPPER];
2661 root = select_reloc_root(trans, rc, upper, edges);
2662 BUG_ON(!root);
2663
2664 if (upper->eb && !upper->locked) {
2665 if (!lowest) {
2666 ret = btrfs_bin_search(upper->eb, key,
2667 upper->level, &slot);
2668 BUG_ON(ret);
2669 bytenr = btrfs_node_blockptr(upper->eb, slot);
2670 if (node->eb->start == bytenr)
2671 goto next;
2672 }
2673 drop_node_buffer(upper);
2674 }
2675
2676 if (!upper->eb) {
2677 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2678 if (ret < 0) {
2679 err = ret;
2680 break;
2681 }
2682 BUG_ON(ret > 0);
2683
2684 if (!upper->eb) {
2685 upper->eb = path->nodes[upper->level];
2686 path->nodes[upper->level] = NULL;
2687 } else {
2688 BUG_ON(upper->eb != path->nodes[upper->level]);
2689 }
2690
2691 upper->locked = 1;
2692 path->locks[upper->level] = 0;
2693
2694 slot = path->slots[upper->level];
2695 btrfs_release_path(path);
2696 } else {
2697 ret = btrfs_bin_search(upper->eb, key, upper->level,
2698 &slot);
2699 BUG_ON(ret);
2700 }
2701
2702 bytenr = btrfs_node_blockptr(upper->eb, slot);
2703 if (lowest) {
2704 BUG_ON(bytenr != node->bytenr);
2705 } else {
2706 if (node->eb->start == bytenr)
2707 goto next;
2708 }
2709
2710 blocksize = root->nodesize;
2711 generation = btrfs_node_ptr_generation(upper->eb, slot);
2712 eb = read_tree_block(root, bytenr, generation);
2713 if (!eb || !extent_buffer_uptodate(eb)) {
2714 free_extent_buffer(eb);
2715 err = -EIO;
2716 goto next;
2717 }
2718 btrfs_tree_lock(eb);
2719 btrfs_set_lock_blocking(eb);
2720
2721 if (!node->eb) {
2722 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2723 slot, &eb);
2724 btrfs_tree_unlock(eb);
2725 free_extent_buffer(eb);
2726 if (ret < 0) {
2727 err = ret;
2728 goto next;
2729 }
2730 BUG_ON(node->eb != eb);
2731 } else {
2732 btrfs_set_node_blockptr(upper->eb, slot,
2733 node->eb->start);
2734 btrfs_set_node_ptr_generation(upper->eb, slot,
2735 trans->transid);
2736 btrfs_mark_buffer_dirty(upper->eb);
2737
2738 ret = btrfs_inc_extent_ref(trans, root,
2739 node->eb->start, blocksize,
2740 upper->eb->start,
2741 btrfs_header_owner(upper->eb),
2742 node->level, 0, 1);
2743 BUG_ON(ret);
2744
2745 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2746 BUG_ON(ret);
2747 }
2748 next:
2749 if (!upper->pending)
2750 drop_node_buffer(upper);
2751 else
2752 unlock_node_buffer(upper);
2753 if (err)
2754 break;
2755 }
2756
2757 if (!err && node->pending) {
2758 drop_node_buffer(node);
2759 list_move_tail(&node->list, &rc->backref_cache.changed);
2760 node->pending = 0;
2761 }
2762
2763 path->lowest_level = 0;
2764 BUG_ON(err == -ENOSPC);
2765 return err;
2766 }
2767
2768 static int link_to_upper(struct btrfs_trans_handle *trans,
2769 struct reloc_control *rc,
2770 struct backref_node *node,
2771 struct btrfs_path *path)
2772 {
2773 struct btrfs_key key;
2774
2775 btrfs_node_key_to_cpu(node->eb, &key, 0);
2776 return do_relocation(trans, rc, node, &key, path, 0);
2777 }
2778
2779 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2780 struct reloc_control *rc,
2781 struct btrfs_path *path, int err)
2782 {
2783 LIST_HEAD(list);
2784 struct backref_cache *cache = &rc->backref_cache;
2785 struct backref_node *node;
2786 int level;
2787 int ret;
2788
2789 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2790 while (!list_empty(&cache->pending[level])) {
2791 node = list_entry(cache->pending[level].next,
2792 struct backref_node, list);
2793 list_move_tail(&node->list, &list);
2794 BUG_ON(!node->pending);
2795
2796 if (!err) {
2797 ret = link_to_upper(trans, rc, node, path);
2798 if (ret < 0)
2799 err = ret;
2800 }
2801 }
2802 list_splice_init(&list, &cache->pending[level]);
2803 }
2804 return err;
2805 }
2806
2807 static void mark_block_processed(struct reloc_control *rc,
2808 u64 bytenr, u32 blocksize)
2809 {
2810 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2811 EXTENT_DIRTY, GFP_NOFS);
2812 }
2813
2814 static void __mark_block_processed(struct reloc_control *rc,
2815 struct backref_node *node)
2816 {
2817 u32 blocksize;
2818 if (node->level == 0 ||
2819 in_block_group(node->bytenr, rc->block_group)) {
2820 blocksize = rc->extent_root->nodesize;
2821 mark_block_processed(rc, node->bytenr, blocksize);
2822 }
2823 node->processed = 1;
2824 }
2825
2826 /*
2827 * mark a block and all blocks directly/indirectly reference the block
2828 * as processed.
2829 */
2830 static void update_processed_blocks(struct reloc_control *rc,
2831 struct backref_node *node)
2832 {
2833 struct backref_node *next = node;
2834 struct backref_edge *edge;
2835 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2836 int index = 0;
2837
2838 while (next) {
2839 cond_resched();
2840 while (1) {
2841 if (next->processed)
2842 break;
2843
2844 __mark_block_processed(rc, next);
2845
2846 if (list_empty(&next->upper))
2847 break;
2848
2849 edge = list_entry(next->upper.next,
2850 struct backref_edge, list[LOWER]);
2851 edges[index++] = edge;
2852 next = edge->node[UPPER];
2853 }
2854 next = walk_down_backref(edges, &index);
2855 }
2856 }
2857
2858 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2859 {
2860 u32 blocksize = rc->extent_root->nodesize;
2861
2862 if (test_range_bit(&rc->processed_blocks, bytenr,
2863 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2864 return 1;
2865 return 0;
2866 }
2867
2868 static int get_tree_block_key(struct reloc_control *rc,
2869 struct tree_block *block)
2870 {
2871 struct extent_buffer *eb;
2872
2873 BUG_ON(block->key_ready);
2874 eb = read_tree_block(rc->extent_root, block->bytenr,
2875 block->key.offset);
2876 if (!eb || !extent_buffer_uptodate(eb)) {
2877 free_extent_buffer(eb);
2878 return -EIO;
2879 }
2880 WARN_ON(btrfs_header_level(eb) != block->level);
2881 if (block->level == 0)
2882 btrfs_item_key_to_cpu(eb, &block->key, 0);
2883 else
2884 btrfs_node_key_to_cpu(eb, &block->key, 0);
2885 free_extent_buffer(eb);
2886 block->key_ready = 1;
2887 return 0;
2888 }
2889
2890 /*
2891 * helper function to relocate a tree block
2892 */
2893 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2894 struct reloc_control *rc,
2895 struct backref_node *node,
2896 struct btrfs_key *key,
2897 struct btrfs_path *path)
2898 {
2899 struct btrfs_root *root;
2900 int ret = 0;
2901
2902 if (!node)
2903 return 0;
2904
2905 BUG_ON(node->processed);
2906 root = select_one_root(trans, node);
2907 if (root == ERR_PTR(-ENOENT)) {
2908 update_processed_blocks(rc, node);
2909 goto out;
2910 }
2911
2912 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2913 ret = reserve_metadata_space(trans, rc, node);
2914 if (ret)
2915 goto out;
2916 }
2917
2918 if (root) {
2919 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2920 BUG_ON(node->new_bytenr);
2921 BUG_ON(!list_empty(&node->list));
2922 btrfs_record_root_in_trans(trans, root);
2923 root = root->reloc_root;
2924 node->new_bytenr = root->node->start;
2925 node->root = root;
2926 list_add_tail(&node->list, &rc->backref_cache.changed);
2927 } else {
2928 path->lowest_level = node->level;
2929 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2930 btrfs_release_path(path);
2931 if (ret > 0)
2932 ret = 0;
2933 }
2934 if (!ret)
2935 update_processed_blocks(rc, node);
2936 } else {
2937 ret = do_relocation(trans, rc, node, key, path, 1);
2938 }
2939 out:
2940 if (ret || node->level == 0 || node->cowonly)
2941 remove_backref_node(&rc->backref_cache, node);
2942 return ret;
2943 }
2944
2945 /*
2946 * relocate a list of blocks
2947 */
2948 static noinline_for_stack
2949 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2950 struct reloc_control *rc, struct rb_root *blocks)
2951 {
2952 struct backref_node *node;
2953 struct btrfs_path *path;
2954 struct tree_block *block;
2955 struct rb_node *rb_node;
2956 int ret;
2957 int err = 0;
2958
2959 path = btrfs_alloc_path();
2960 if (!path) {
2961 err = -ENOMEM;
2962 goto out_free_blocks;
2963 }
2964
2965 rb_node = rb_first(blocks);
2966 while (rb_node) {
2967 block = rb_entry(rb_node, struct tree_block, rb_node);
2968 if (!block->key_ready)
2969 readahead_tree_block(rc->extent_root, block->bytenr);
2970 rb_node = rb_next(rb_node);
2971 }
2972
2973 rb_node = rb_first(blocks);
2974 while (rb_node) {
2975 block = rb_entry(rb_node, struct tree_block, rb_node);
2976 if (!block->key_ready) {
2977 err = get_tree_block_key(rc, block);
2978 if (err)
2979 goto out_free_path;
2980 }
2981 rb_node = rb_next(rb_node);
2982 }
2983
2984 rb_node = rb_first(blocks);
2985 while (rb_node) {
2986 block = rb_entry(rb_node, struct tree_block, rb_node);
2987
2988 node = build_backref_tree(rc, &block->key,
2989 block->level, block->bytenr);
2990 if (IS_ERR(node)) {
2991 err = PTR_ERR(node);
2992 goto out;
2993 }
2994
2995 ret = relocate_tree_block(trans, rc, node, &block->key,
2996 path);
2997 if (ret < 0) {
2998 if (ret != -EAGAIN || rb_node == rb_first(blocks))
2999 err = ret;
3000 goto out;
3001 }
3002 rb_node = rb_next(rb_node);
3003 }
3004 out:
3005 err = finish_pending_nodes(trans, rc, path, err);
3006
3007 out_free_path:
3008 btrfs_free_path(path);
3009 out_free_blocks:
3010 free_block_list(blocks);
3011 return err;
3012 }
3013
3014 static noinline_for_stack
3015 int prealloc_file_extent_cluster(struct inode *inode,
3016 struct file_extent_cluster *cluster)
3017 {
3018 u64 alloc_hint = 0;
3019 u64 start;
3020 u64 end;
3021 u64 offset = BTRFS_I(inode)->index_cnt;
3022 u64 num_bytes;
3023 int nr = 0;
3024 int ret = 0;
3025
3026 BUG_ON(cluster->start != cluster->boundary[0]);
3027 mutex_lock(&inode->i_mutex);
3028
3029 ret = btrfs_check_data_free_space(inode, cluster->end +
3030 1 - cluster->start);
3031 if (ret)
3032 goto out;
3033
3034 while (nr < cluster->nr) {
3035 start = cluster->boundary[nr] - offset;
3036 if (nr + 1 < cluster->nr)
3037 end = cluster->boundary[nr + 1] - 1 - offset;
3038 else
3039 end = cluster->end - offset;
3040
3041 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3042 num_bytes = end + 1 - start;
3043 ret = btrfs_prealloc_file_range(inode, 0, start,
3044 num_bytes, num_bytes,
3045 end + 1, &alloc_hint);
3046 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3047 if (ret)
3048 break;
3049 nr++;
3050 }
3051 btrfs_free_reserved_data_space(inode, cluster->end +
3052 1 - cluster->start);
3053 out:
3054 mutex_unlock(&inode->i_mutex);
3055 return ret;
3056 }
3057
3058 static noinline_for_stack
3059 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3060 u64 block_start)
3061 {
3062 struct btrfs_root *root = BTRFS_I(inode)->root;
3063 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3064 struct extent_map *em;
3065 int ret = 0;
3066
3067 em = alloc_extent_map();
3068 if (!em)
3069 return -ENOMEM;
3070
3071 em->start = start;
3072 em->len = end + 1 - start;
3073 em->block_len = em->len;
3074 em->block_start = block_start;
3075 em->bdev = root->fs_info->fs_devices->latest_bdev;
3076 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3077
3078 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3079 while (1) {
3080 write_lock(&em_tree->lock);
3081 ret = add_extent_mapping(em_tree, em, 0);
3082 write_unlock(&em_tree->lock);
3083 if (ret != -EEXIST) {
3084 free_extent_map(em);
3085 break;
3086 }
3087 btrfs_drop_extent_cache(inode, start, end, 0);
3088 }
3089 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3090 return ret;
3091 }
3092
3093 static int relocate_file_extent_cluster(struct inode *inode,
3094 struct file_extent_cluster *cluster)
3095 {
3096 u64 page_start;
3097 u64 page_end;
3098 u64 offset = BTRFS_I(inode)->index_cnt;
3099 unsigned long index;
3100 unsigned long last_index;
3101 struct page *page;
3102 struct file_ra_state *ra;
3103 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3104 int nr = 0;
3105 int ret = 0;
3106
3107 if (!cluster->nr)
3108 return 0;
3109
3110 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3111 if (!ra)
3112 return -ENOMEM;
3113
3114 ret = prealloc_file_extent_cluster(inode, cluster);
3115 if (ret)
3116 goto out;
3117
3118 file_ra_state_init(ra, inode->i_mapping);
3119
3120 ret = setup_extent_mapping(inode, cluster->start - offset,
3121 cluster->end - offset, cluster->start);
3122 if (ret)
3123 goto out;
3124
3125 index = (cluster->start - offset) >> PAGE_CACHE_SHIFT;
3126 last_index = (cluster->end - offset) >> PAGE_CACHE_SHIFT;
3127 while (index <= last_index) {
3128 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_CACHE_SIZE);
3129 if (ret)
3130 goto out;
3131
3132 page = find_lock_page(inode->i_mapping, index);
3133 if (!page) {
3134 page_cache_sync_readahead(inode->i_mapping,
3135 ra, NULL, index,
3136 last_index + 1 - index);
3137 page = find_or_create_page(inode->i_mapping, index,
3138 mask);
3139 if (!page) {
3140 btrfs_delalloc_release_metadata(inode,
3141 PAGE_CACHE_SIZE);
3142 ret = -ENOMEM;
3143 goto out;
3144 }
3145 }
3146
3147 if (PageReadahead(page)) {
3148 page_cache_async_readahead(inode->i_mapping,
3149 ra, NULL, page, index,
3150 last_index + 1 - index);
3151 }
3152
3153 if (!PageUptodate(page)) {
3154 btrfs_readpage(NULL, page);
3155 lock_page(page);
3156 if (!PageUptodate(page)) {
3157 unlock_page(page);
3158 page_cache_release(page);
3159 btrfs_delalloc_release_metadata(inode,
3160 PAGE_CACHE_SIZE);
3161 ret = -EIO;
3162 goto out;
3163 }
3164 }
3165
3166 page_start = page_offset(page);
3167 page_end = page_start + PAGE_CACHE_SIZE - 1;
3168
3169 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3170
3171 set_page_extent_mapped(page);
3172
3173 if (nr < cluster->nr &&
3174 page_start + offset == cluster->boundary[nr]) {
3175 set_extent_bits(&BTRFS_I(inode)->io_tree,
3176 page_start, page_end,
3177 EXTENT_BOUNDARY, GFP_NOFS);
3178 nr++;
3179 }
3180
3181 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3182 set_page_dirty(page);
3183
3184 unlock_extent(&BTRFS_I(inode)->io_tree,
3185 page_start, page_end);
3186 unlock_page(page);
3187 page_cache_release(page);
3188
3189 index++;
3190 balance_dirty_pages_ratelimited(inode->i_mapping);
3191 btrfs_throttle(BTRFS_I(inode)->root);
3192 }
3193 WARN_ON(nr != cluster->nr);
3194 out:
3195 kfree(ra);
3196 return ret;
3197 }
3198
3199 static noinline_for_stack
3200 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3201 struct file_extent_cluster *cluster)
3202 {
3203 int ret;
3204
3205 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3206 ret = relocate_file_extent_cluster(inode, cluster);
3207 if (ret)
3208 return ret;
3209 cluster->nr = 0;
3210 }
3211
3212 if (!cluster->nr)
3213 cluster->start = extent_key->objectid;
3214 else
3215 BUG_ON(cluster->nr >= MAX_EXTENTS);
3216 cluster->end = extent_key->objectid + extent_key->offset - 1;
3217 cluster->boundary[cluster->nr] = extent_key->objectid;
3218 cluster->nr++;
3219
3220 if (cluster->nr >= MAX_EXTENTS) {
3221 ret = relocate_file_extent_cluster(inode, cluster);
3222 if (ret)
3223 return ret;
3224 cluster->nr = 0;
3225 }
3226 return 0;
3227 }
3228
3229 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3230 static int get_ref_objectid_v0(struct reloc_control *rc,
3231 struct btrfs_path *path,
3232 struct btrfs_key *extent_key,
3233 u64 *ref_objectid, int *path_change)
3234 {
3235 struct btrfs_key key;
3236 struct extent_buffer *leaf;
3237 struct btrfs_extent_ref_v0 *ref0;
3238 int ret;
3239 int slot;
3240
3241 leaf = path->nodes[0];
3242 slot = path->slots[0];
3243 while (1) {
3244 if (slot >= btrfs_header_nritems(leaf)) {
3245 ret = btrfs_next_leaf(rc->extent_root, path);
3246 if (ret < 0)
3247 return ret;
3248 BUG_ON(ret > 0);
3249 leaf = path->nodes[0];
3250 slot = path->slots[0];
3251 if (path_change)
3252 *path_change = 1;
3253 }
3254 btrfs_item_key_to_cpu(leaf, &key, slot);
3255 if (key.objectid != extent_key->objectid)
3256 return -ENOENT;
3257
3258 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3259 slot++;
3260 continue;
3261 }
3262 ref0 = btrfs_item_ptr(leaf, slot,
3263 struct btrfs_extent_ref_v0);
3264 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3265 break;
3266 }
3267 return 0;
3268 }
3269 #endif
3270
3271 /*
3272 * helper to add a tree block to the list.
3273 * the major work is getting the generation and level of the block
3274 */
3275 static int add_tree_block(struct reloc_control *rc,
3276 struct btrfs_key *extent_key,
3277 struct btrfs_path *path,
3278 struct rb_root *blocks)
3279 {
3280 struct extent_buffer *eb;
3281 struct btrfs_extent_item *ei;
3282 struct btrfs_tree_block_info *bi;
3283 struct tree_block *block;
3284 struct rb_node *rb_node;
3285 u32 item_size;
3286 int level = -1;
3287 u64 generation;
3288
3289 eb = path->nodes[0];
3290 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3291
3292 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3293 item_size >= sizeof(*ei) + sizeof(*bi)) {
3294 ei = btrfs_item_ptr(eb, path->slots[0],
3295 struct btrfs_extent_item);
3296 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3297 bi = (struct btrfs_tree_block_info *)(ei + 1);
3298 level = btrfs_tree_block_level(eb, bi);
3299 } else {
3300 level = (int)extent_key->offset;
3301 }
3302 generation = btrfs_extent_generation(eb, ei);
3303 } else {
3304 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3305 u64 ref_owner;
3306 int ret;
3307
3308 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3309 ret = get_ref_objectid_v0(rc, path, extent_key,
3310 &ref_owner, NULL);
3311 if (ret < 0)
3312 return ret;
3313 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3314 level = (int)ref_owner;
3315 /* FIXME: get real generation */
3316 generation = 0;
3317 #else
3318 BUG();
3319 #endif
3320 }
3321
3322 btrfs_release_path(path);
3323
3324 BUG_ON(level == -1);
3325
3326 block = kmalloc(sizeof(*block), GFP_NOFS);
3327 if (!block)
3328 return -ENOMEM;
3329
3330 block->bytenr = extent_key->objectid;
3331 block->key.objectid = rc->extent_root->nodesize;
3332 block->key.offset = generation;
3333 block->level = level;
3334 block->key_ready = 0;
3335
3336 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3337 if (rb_node)
3338 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3339
3340 return 0;
3341 }
3342
3343 /*
3344 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3345 */
3346 static int __add_tree_block(struct reloc_control *rc,
3347 u64 bytenr, u32 blocksize,
3348 struct rb_root *blocks)
3349 {
3350 struct btrfs_path *path;
3351 struct btrfs_key key;
3352 int ret;
3353 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3354 SKINNY_METADATA);
3355
3356 if (tree_block_processed(bytenr, rc))
3357 return 0;
3358
3359 if (tree_search(blocks, bytenr))
3360 return 0;
3361
3362 path = btrfs_alloc_path();
3363 if (!path)
3364 return -ENOMEM;
3365 again:
3366 key.objectid = bytenr;
3367 if (skinny) {
3368 key.type = BTRFS_METADATA_ITEM_KEY;
3369 key.offset = (u64)-1;
3370 } else {
3371 key.type = BTRFS_EXTENT_ITEM_KEY;
3372 key.offset = blocksize;
3373 }
3374
3375 path->search_commit_root = 1;
3376 path->skip_locking = 1;
3377 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3378 if (ret < 0)
3379 goto out;
3380
3381 if (ret > 0 && skinny) {
3382 if (path->slots[0]) {
3383 path->slots[0]--;
3384 btrfs_item_key_to_cpu(path->nodes[0], &key,
3385 path->slots[0]);
3386 if (key.objectid == bytenr &&
3387 (key.type == BTRFS_METADATA_ITEM_KEY ||
3388 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3389 key.offset == blocksize)))
3390 ret = 0;
3391 }
3392
3393 if (ret) {
3394 skinny = false;
3395 btrfs_release_path(path);
3396 goto again;
3397 }
3398 }
3399 BUG_ON(ret);
3400
3401 ret = add_tree_block(rc, &key, path, blocks);
3402 out:
3403 btrfs_free_path(path);
3404 return ret;
3405 }
3406
3407 /*
3408 * helper to check if the block use full backrefs for pointers in it
3409 */
3410 static int block_use_full_backref(struct reloc_control *rc,
3411 struct extent_buffer *eb)
3412 {
3413 u64 flags;
3414 int ret;
3415
3416 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3417 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3418 return 1;
3419
3420 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3421 eb->start, btrfs_header_level(eb), 1,
3422 NULL, &flags);
3423 BUG_ON(ret);
3424
3425 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3426 ret = 1;
3427 else
3428 ret = 0;
3429 return ret;
3430 }
3431
3432 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3433 struct inode *inode, u64 ino)
3434 {
3435 struct btrfs_key key;
3436 struct btrfs_root *root = fs_info->tree_root;
3437 struct btrfs_trans_handle *trans;
3438 int ret = 0;
3439
3440 if (inode)
3441 goto truncate;
3442
3443 key.objectid = ino;
3444 key.type = BTRFS_INODE_ITEM_KEY;
3445 key.offset = 0;
3446
3447 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3448 if (IS_ERR(inode) || is_bad_inode(inode)) {
3449 if (!IS_ERR(inode))
3450 iput(inode);
3451 return -ENOENT;
3452 }
3453
3454 truncate:
3455 ret = btrfs_check_trunc_cache_free_space(root,
3456 &fs_info->global_block_rsv);
3457 if (ret)
3458 goto out;
3459
3460 trans = btrfs_join_transaction(root);
3461 if (IS_ERR(trans)) {
3462 ret = PTR_ERR(trans);
3463 goto out;
3464 }
3465
3466 ret = btrfs_truncate_free_space_cache(root, trans, inode);
3467
3468 btrfs_end_transaction(trans, root);
3469 btrfs_btree_balance_dirty(root);
3470 out:
3471 iput(inode);
3472 return ret;
3473 }
3474
3475 /*
3476 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3477 * this function scans fs tree to find blocks reference the data extent
3478 */
3479 static int find_data_references(struct reloc_control *rc,
3480 struct btrfs_key *extent_key,
3481 struct extent_buffer *leaf,
3482 struct btrfs_extent_data_ref *ref,
3483 struct rb_root *blocks)
3484 {
3485 struct btrfs_path *path;
3486 struct tree_block *block;
3487 struct btrfs_root *root;
3488 struct btrfs_file_extent_item *fi;
3489 struct rb_node *rb_node;
3490 struct btrfs_key key;
3491 u64 ref_root;
3492 u64 ref_objectid;
3493 u64 ref_offset;
3494 u32 ref_count;
3495 u32 nritems;
3496 int err = 0;
3497 int added = 0;
3498 int counted;
3499 int ret;
3500
3501 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3502 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3503 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3504 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3505
3506 /*
3507 * This is an extent belonging to the free space cache, lets just delete
3508 * it and redo the search.
3509 */
3510 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3511 ret = delete_block_group_cache(rc->extent_root->fs_info,
3512 NULL, ref_objectid);
3513 if (ret != -ENOENT)
3514 return ret;
3515 ret = 0;
3516 }
3517
3518 path = btrfs_alloc_path();
3519 if (!path)
3520 return -ENOMEM;
3521 path->reada = 1;
3522
3523 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3524 if (IS_ERR(root)) {
3525 err = PTR_ERR(root);
3526 goto out;
3527 }
3528
3529 key.objectid = ref_objectid;
3530 key.type = BTRFS_EXTENT_DATA_KEY;
3531 if (ref_offset > ((u64)-1 << 32))
3532 key.offset = 0;
3533 else
3534 key.offset = ref_offset;
3535
3536 path->search_commit_root = 1;
3537 path->skip_locking = 1;
3538 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3539 if (ret < 0) {
3540 err = ret;
3541 goto out;
3542 }
3543
3544 leaf = path->nodes[0];
3545 nritems = btrfs_header_nritems(leaf);
3546 /*
3547 * the references in tree blocks that use full backrefs
3548 * are not counted in
3549 */
3550 if (block_use_full_backref(rc, leaf))
3551 counted = 0;
3552 else
3553 counted = 1;
3554 rb_node = tree_search(blocks, leaf->start);
3555 if (rb_node) {
3556 if (counted)
3557 added = 1;
3558 else
3559 path->slots[0] = nritems;
3560 }
3561
3562 while (ref_count > 0) {
3563 while (path->slots[0] >= nritems) {
3564 ret = btrfs_next_leaf(root, path);
3565 if (ret < 0) {
3566 err = ret;
3567 goto out;
3568 }
3569 if (WARN_ON(ret > 0))
3570 goto out;
3571
3572 leaf = path->nodes[0];
3573 nritems = btrfs_header_nritems(leaf);
3574 added = 0;
3575
3576 if (block_use_full_backref(rc, leaf))
3577 counted = 0;
3578 else
3579 counted = 1;
3580 rb_node = tree_search(blocks, leaf->start);
3581 if (rb_node) {
3582 if (counted)
3583 added = 1;
3584 else
3585 path->slots[0] = nritems;
3586 }
3587 }
3588
3589 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3590 if (WARN_ON(key.objectid != ref_objectid ||
3591 key.type != BTRFS_EXTENT_DATA_KEY))
3592 break;
3593
3594 fi = btrfs_item_ptr(leaf, path->slots[0],
3595 struct btrfs_file_extent_item);
3596
3597 if (btrfs_file_extent_type(leaf, fi) ==
3598 BTRFS_FILE_EXTENT_INLINE)
3599 goto next;
3600
3601 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3602 extent_key->objectid)
3603 goto next;
3604
3605 key.offset -= btrfs_file_extent_offset(leaf, fi);
3606 if (key.offset != ref_offset)
3607 goto next;
3608
3609 if (counted)
3610 ref_count--;
3611 if (added)
3612 goto next;
3613
3614 if (!tree_block_processed(leaf->start, rc)) {
3615 block = kmalloc(sizeof(*block), GFP_NOFS);
3616 if (!block) {
3617 err = -ENOMEM;
3618 break;
3619 }
3620 block->bytenr = leaf->start;
3621 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3622 block->level = 0;
3623 block->key_ready = 1;
3624 rb_node = tree_insert(blocks, block->bytenr,
3625 &block->rb_node);
3626 if (rb_node)
3627 backref_tree_panic(rb_node, -EEXIST,
3628 block->bytenr);
3629 }
3630 if (counted)
3631 added = 1;
3632 else
3633 path->slots[0] = nritems;
3634 next:
3635 path->slots[0]++;
3636
3637 }
3638 out:
3639 btrfs_free_path(path);
3640 return err;
3641 }
3642
3643 /*
3644 * helper to find all tree blocks that reference a given data extent
3645 */
3646 static noinline_for_stack
3647 int add_data_references(struct reloc_control *rc,
3648 struct btrfs_key *extent_key,
3649 struct btrfs_path *path,
3650 struct rb_root *blocks)
3651 {
3652 struct btrfs_key key;
3653 struct extent_buffer *eb;
3654 struct btrfs_extent_data_ref *dref;
3655 struct btrfs_extent_inline_ref *iref;
3656 unsigned long ptr;
3657 unsigned long end;
3658 u32 blocksize = rc->extent_root->nodesize;
3659 int ret = 0;
3660 int err = 0;
3661
3662 eb = path->nodes[0];
3663 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3664 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3665 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3666 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3667 ptr = end;
3668 else
3669 #endif
3670 ptr += sizeof(struct btrfs_extent_item);
3671
3672 while (ptr < end) {
3673 iref = (struct btrfs_extent_inline_ref *)ptr;
3674 key.type = btrfs_extent_inline_ref_type(eb, iref);
3675 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3676 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3677 ret = __add_tree_block(rc, key.offset, blocksize,
3678 blocks);
3679 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3680 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3681 ret = find_data_references(rc, extent_key,
3682 eb, dref, blocks);
3683 } else {
3684 BUG();
3685 }
3686 if (ret) {
3687 err = ret;
3688 goto out;
3689 }
3690 ptr += btrfs_extent_inline_ref_size(key.type);
3691 }
3692 WARN_ON(ptr > end);
3693
3694 while (1) {
3695 cond_resched();
3696 eb = path->nodes[0];
3697 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3698 ret = btrfs_next_leaf(rc->extent_root, path);
3699 if (ret < 0) {
3700 err = ret;
3701 break;
3702 }
3703 if (ret > 0)
3704 break;
3705 eb = path->nodes[0];
3706 }
3707
3708 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3709 if (key.objectid != extent_key->objectid)
3710 break;
3711
3712 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3713 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3714 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3715 #else
3716 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3717 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3718 #endif
3719 ret = __add_tree_block(rc, key.offset, blocksize,
3720 blocks);
3721 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3722 dref = btrfs_item_ptr(eb, path->slots[0],
3723 struct btrfs_extent_data_ref);
3724 ret = find_data_references(rc, extent_key,
3725 eb, dref, blocks);
3726 } else {
3727 ret = 0;
3728 }
3729 if (ret) {
3730 err = ret;
3731 break;
3732 }
3733 path->slots[0]++;
3734 }
3735 out:
3736 btrfs_release_path(path);
3737 if (err)
3738 free_block_list(blocks);
3739 return err;
3740 }
3741
3742 /*
3743 * helper to find next unprocessed extent
3744 */
3745 static noinline_for_stack
3746 int find_next_extent(struct btrfs_trans_handle *trans,
3747 struct reloc_control *rc, struct btrfs_path *path,
3748 struct btrfs_key *extent_key)
3749 {
3750 struct btrfs_key key;
3751 struct extent_buffer *leaf;
3752 u64 start, end, last;
3753 int ret;
3754
3755 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3756 while (1) {
3757 cond_resched();
3758 if (rc->search_start >= last) {
3759 ret = 1;
3760 break;
3761 }
3762
3763 key.objectid = rc->search_start;
3764 key.type = BTRFS_EXTENT_ITEM_KEY;
3765 key.offset = 0;
3766
3767 path->search_commit_root = 1;
3768 path->skip_locking = 1;
3769 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3770 0, 0);
3771 if (ret < 0)
3772 break;
3773 next:
3774 leaf = path->nodes[0];
3775 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3776 ret = btrfs_next_leaf(rc->extent_root, path);
3777 if (ret != 0)
3778 break;
3779 leaf = path->nodes[0];
3780 }
3781
3782 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3783 if (key.objectid >= last) {
3784 ret = 1;
3785 break;
3786 }
3787
3788 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3789 key.type != BTRFS_METADATA_ITEM_KEY) {
3790 path->slots[0]++;
3791 goto next;
3792 }
3793
3794 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3795 key.objectid + key.offset <= rc->search_start) {
3796 path->slots[0]++;
3797 goto next;
3798 }
3799
3800 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3801 key.objectid + rc->extent_root->nodesize <=
3802 rc->search_start) {
3803 path->slots[0]++;
3804 goto next;
3805 }
3806
3807 ret = find_first_extent_bit(&rc->processed_blocks,
3808 key.objectid, &start, &end,
3809 EXTENT_DIRTY, NULL);
3810
3811 if (ret == 0 && start <= key.objectid) {
3812 btrfs_release_path(path);
3813 rc->search_start = end + 1;
3814 } else {
3815 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3816 rc->search_start = key.objectid + key.offset;
3817 else
3818 rc->search_start = key.objectid +
3819 rc->extent_root->nodesize;
3820 memcpy(extent_key, &key, sizeof(key));
3821 return 0;
3822 }
3823 }
3824 btrfs_release_path(path);
3825 return ret;
3826 }
3827
3828 static void set_reloc_control(struct reloc_control *rc)
3829 {
3830 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3831
3832 mutex_lock(&fs_info->reloc_mutex);
3833 fs_info->reloc_ctl = rc;
3834 mutex_unlock(&fs_info->reloc_mutex);
3835 }
3836
3837 static void unset_reloc_control(struct reloc_control *rc)
3838 {
3839 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3840
3841 mutex_lock(&fs_info->reloc_mutex);
3842 fs_info->reloc_ctl = NULL;
3843 mutex_unlock(&fs_info->reloc_mutex);
3844 }
3845
3846 static int check_extent_flags(u64 flags)
3847 {
3848 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3849 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3850 return 1;
3851 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3852 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3853 return 1;
3854 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3855 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3856 return 1;
3857 return 0;
3858 }
3859
3860 static noinline_for_stack
3861 int prepare_to_relocate(struct reloc_control *rc)
3862 {
3863 struct btrfs_trans_handle *trans;
3864
3865 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3866 BTRFS_BLOCK_RSV_TEMP);
3867 if (!rc->block_rsv)
3868 return -ENOMEM;
3869
3870 memset(&rc->cluster, 0, sizeof(rc->cluster));
3871 rc->search_start = rc->block_group->key.objectid;
3872 rc->extents_found = 0;
3873 rc->nodes_relocated = 0;
3874 rc->merging_rsv_size = 0;
3875 rc->reserved_bytes = 0;
3876 rc->block_rsv->size = rc->extent_root->nodesize *
3877 RELOCATION_RESERVED_NODES;
3878
3879 rc->create_reloc_tree = 1;
3880 set_reloc_control(rc);
3881
3882 trans = btrfs_join_transaction(rc->extent_root);
3883 if (IS_ERR(trans)) {
3884 unset_reloc_control(rc);
3885 /*
3886 * extent tree is not a ref_cow tree and has no reloc_root to
3887 * cleanup. And callers are responsible to free the above
3888 * block rsv.
3889 */
3890 return PTR_ERR(trans);
3891 }
3892 btrfs_commit_transaction(trans, rc->extent_root);
3893 return 0;
3894 }
3895
3896 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3897 {
3898 struct rb_root blocks = RB_ROOT;
3899 struct btrfs_key key;
3900 struct btrfs_trans_handle *trans = NULL;
3901 struct btrfs_path *path;
3902 struct btrfs_extent_item *ei;
3903 u64 flags;
3904 u32 item_size;
3905 int ret;
3906 int err = 0;
3907 int progress = 0;
3908
3909 path = btrfs_alloc_path();
3910 if (!path)
3911 return -ENOMEM;
3912 path->reada = 1;
3913
3914 ret = prepare_to_relocate(rc);
3915 if (ret) {
3916 err = ret;
3917 goto out_free;
3918 }
3919
3920 while (1) {
3921 rc->reserved_bytes = 0;
3922 ret = btrfs_block_rsv_refill(rc->extent_root,
3923 rc->block_rsv, rc->block_rsv->size,
3924 BTRFS_RESERVE_FLUSH_ALL);
3925 if (ret) {
3926 err = ret;
3927 break;
3928 }
3929 progress++;
3930 trans = btrfs_start_transaction(rc->extent_root, 0);
3931 if (IS_ERR(trans)) {
3932 err = PTR_ERR(trans);
3933 trans = NULL;
3934 break;
3935 }
3936 restart:
3937 if (update_backref_cache(trans, &rc->backref_cache)) {
3938 btrfs_end_transaction(trans, rc->extent_root);
3939 continue;
3940 }
3941
3942 ret = find_next_extent(trans, rc, path, &key);
3943 if (ret < 0)
3944 err = ret;
3945 if (ret != 0)
3946 break;
3947
3948 rc->extents_found++;
3949
3950 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3951 struct btrfs_extent_item);
3952 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3953 if (item_size >= sizeof(*ei)) {
3954 flags = btrfs_extent_flags(path->nodes[0], ei);
3955 ret = check_extent_flags(flags);
3956 BUG_ON(ret);
3957
3958 } else {
3959 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3960 u64 ref_owner;
3961 int path_change = 0;
3962
3963 BUG_ON(item_size !=
3964 sizeof(struct btrfs_extent_item_v0));
3965 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3966 &path_change);
3967 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3968 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3969 else
3970 flags = BTRFS_EXTENT_FLAG_DATA;
3971
3972 if (path_change) {
3973 btrfs_release_path(path);
3974
3975 path->search_commit_root = 1;
3976 path->skip_locking = 1;
3977 ret = btrfs_search_slot(NULL, rc->extent_root,
3978 &key, path, 0, 0);
3979 if (ret < 0) {
3980 err = ret;
3981 break;
3982 }
3983 BUG_ON(ret > 0);
3984 }
3985 #else
3986 BUG();
3987 #endif
3988 }
3989
3990 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3991 ret = add_tree_block(rc, &key, path, &blocks);
3992 } else if (rc->stage == UPDATE_DATA_PTRS &&
3993 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3994 ret = add_data_references(rc, &key, path, &blocks);
3995 } else {
3996 btrfs_release_path(path);
3997 ret = 0;
3998 }
3999 if (ret < 0) {
4000 err = ret;
4001 break;
4002 }
4003
4004 if (!RB_EMPTY_ROOT(&blocks)) {
4005 ret = relocate_tree_blocks(trans, rc, &blocks);
4006 if (ret < 0) {
4007 /*
4008 * if we fail to relocate tree blocks, force to update
4009 * backref cache when committing transaction.
4010 */
4011 rc->backref_cache.last_trans = trans->transid - 1;
4012
4013 if (ret != -EAGAIN) {
4014 err = ret;
4015 break;
4016 }
4017 rc->extents_found--;
4018 rc->search_start = key.objectid;
4019 }
4020 }
4021
4022 btrfs_end_transaction_throttle(trans, rc->extent_root);
4023 btrfs_btree_balance_dirty(rc->extent_root);
4024 trans = NULL;
4025
4026 if (rc->stage == MOVE_DATA_EXTENTS &&
4027 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4028 rc->found_file_extent = 1;
4029 ret = relocate_data_extent(rc->data_inode,
4030 &key, &rc->cluster);
4031 if (ret < 0) {
4032 err = ret;
4033 break;
4034 }
4035 }
4036 }
4037 if (trans && progress && err == -ENOSPC) {
4038 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4039 rc->block_group->flags);
4040 if (ret == 0) {
4041 err = 0;
4042 progress = 0;
4043 goto restart;
4044 }
4045 }
4046
4047 btrfs_release_path(path);
4048 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY,
4049 GFP_NOFS);
4050
4051 if (trans) {
4052 btrfs_end_transaction_throttle(trans, rc->extent_root);
4053 btrfs_btree_balance_dirty(rc->extent_root);
4054 }
4055
4056 if (!err) {
4057 ret = relocate_file_extent_cluster(rc->data_inode,
4058 &rc->cluster);
4059 if (ret < 0)
4060 err = ret;
4061 }
4062
4063 rc->create_reloc_tree = 0;
4064 set_reloc_control(rc);
4065
4066 backref_cache_cleanup(&rc->backref_cache);
4067 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4068
4069 err = prepare_to_merge(rc, err);
4070
4071 merge_reloc_roots(rc);
4072
4073 rc->merge_reloc_tree = 0;
4074 unset_reloc_control(rc);
4075 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4076
4077 /* get rid of pinned extents */
4078 trans = btrfs_join_transaction(rc->extent_root);
4079 if (IS_ERR(trans))
4080 err = PTR_ERR(trans);
4081 else
4082 btrfs_commit_transaction(trans, rc->extent_root);
4083 out_free:
4084 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4085 btrfs_free_path(path);
4086 return err;
4087 }
4088
4089 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4090 struct btrfs_root *root, u64 objectid)
4091 {
4092 struct btrfs_path *path;
4093 struct btrfs_inode_item *item;
4094 struct extent_buffer *leaf;
4095 int ret;
4096
4097 path = btrfs_alloc_path();
4098 if (!path)
4099 return -ENOMEM;
4100
4101 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4102 if (ret)
4103 goto out;
4104
4105 leaf = path->nodes[0];
4106 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4107 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4108 btrfs_set_inode_generation(leaf, item, 1);
4109 btrfs_set_inode_size(leaf, item, 0);
4110 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4111 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4112 BTRFS_INODE_PREALLOC);
4113 btrfs_mark_buffer_dirty(leaf);
4114 out:
4115 btrfs_free_path(path);
4116 return ret;
4117 }
4118
4119 /*
4120 * helper to create inode for data relocation.
4121 * the inode is in data relocation tree and its link count is 0
4122 */
4123 static noinline_for_stack
4124 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4125 struct btrfs_block_group_cache *group)
4126 {
4127 struct inode *inode = NULL;
4128 struct btrfs_trans_handle *trans;
4129 struct btrfs_root *root;
4130 struct btrfs_key key;
4131 u64 objectid = BTRFS_FIRST_FREE_OBJECTID;
4132 int err = 0;
4133
4134 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4135 if (IS_ERR(root))
4136 return ERR_CAST(root);
4137
4138 trans = btrfs_start_transaction(root, 6);
4139 if (IS_ERR(trans))
4140 return ERR_CAST(trans);
4141
4142 err = btrfs_find_free_objectid(root, &objectid);
4143 if (err)
4144 goto out;
4145
4146 err = __insert_orphan_inode(trans, root, objectid);
4147 BUG_ON(err);
4148
4149 key.objectid = objectid;
4150 key.type = BTRFS_INODE_ITEM_KEY;
4151 key.offset = 0;
4152 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4153 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4154 BTRFS_I(inode)->index_cnt = group->key.objectid;
4155
4156 err = btrfs_orphan_add(trans, inode);
4157 out:
4158 btrfs_end_transaction(trans, root);
4159 btrfs_btree_balance_dirty(root);
4160 if (err) {
4161 if (inode)
4162 iput(inode);
4163 inode = ERR_PTR(err);
4164 }
4165 return inode;
4166 }
4167
4168 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4169 {
4170 struct reloc_control *rc;
4171
4172 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4173 if (!rc)
4174 return NULL;
4175
4176 INIT_LIST_HEAD(&rc->reloc_roots);
4177 backref_cache_init(&rc->backref_cache);
4178 mapping_tree_init(&rc->reloc_root_tree);
4179 extent_io_tree_init(&rc->processed_blocks,
4180 fs_info->btree_inode->i_mapping);
4181 return rc;
4182 }
4183
4184 /*
4185 * function to relocate all extents in a block group.
4186 */
4187 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4188 {
4189 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4190 struct reloc_control *rc;
4191 struct inode *inode;
4192 struct btrfs_path *path;
4193 int ret;
4194 int rw = 0;
4195 int err = 0;
4196
4197 rc = alloc_reloc_control(fs_info);
4198 if (!rc)
4199 return -ENOMEM;
4200
4201 rc->extent_root = extent_root;
4202
4203 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4204 BUG_ON(!rc->block_group);
4205
4206 if (!rc->block_group->ro) {
4207 ret = btrfs_set_block_group_ro(extent_root, rc->block_group);
4208 if (ret) {
4209 err = ret;
4210 goto out;
4211 }
4212 rw = 1;
4213 }
4214
4215 path = btrfs_alloc_path();
4216 if (!path) {
4217 err = -ENOMEM;
4218 goto out;
4219 }
4220
4221 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4222 path);
4223 btrfs_free_path(path);
4224
4225 if (!IS_ERR(inode))
4226 ret = delete_block_group_cache(fs_info, inode, 0);
4227 else
4228 ret = PTR_ERR(inode);
4229
4230 if (ret && ret != -ENOENT) {
4231 err = ret;
4232 goto out;
4233 }
4234
4235 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4236 if (IS_ERR(rc->data_inode)) {
4237 err = PTR_ERR(rc->data_inode);
4238 rc->data_inode = NULL;
4239 goto out;
4240 }
4241
4242 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4243 rc->block_group->key.objectid, rc->block_group->flags);
4244
4245 ret = btrfs_start_delalloc_roots(fs_info, 0, -1);
4246 if (ret < 0) {
4247 err = ret;
4248 goto out;
4249 }
4250 btrfs_wait_ordered_roots(fs_info, -1);
4251
4252 while (1) {
4253 mutex_lock(&fs_info->cleaner_mutex);
4254 ret = relocate_block_group(rc);
4255 mutex_unlock(&fs_info->cleaner_mutex);
4256 if (ret < 0) {
4257 err = ret;
4258 goto out;
4259 }
4260
4261 if (rc->extents_found == 0)
4262 break;
4263
4264 btrfs_info(extent_root->fs_info, "found %llu extents",
4265 rc->extents_found);
4266
4267 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4268 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4269 (u64)-1);
4270 if (ret) {
4271 err = ret;
4272 goto out;
4273 }
4274 invalidate_mapping_pages(rc->data_inode->i_mapping,
4275 0, -1);
4276 rc->stage = UPDATE_DATA_PTRS;
4277 }
4278 }
4279
4280 WARN_ON(rc->block_group->pinned > 0);
4281 WARN_ON(rc->block_group->reserved > 0);
4282 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4283 out:
4284 if (err && rw)
4285 btrfs_set_block_group_rw(extent_root, rc->block_group);
4286 iput(rc->data_inode);
4287 btrfs_put_block_group(rc->block_group);
4288 kfree(rc);
4289 return err;
4290 }
4291
4292 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4293 {
4294 struct btrfs_trans_handle *trans;
4295 int ret, err;
4296
4297 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4298 if (IS_ERR(trans))
4299 return PTR_ERR(trans);
4300
4301 memset(&root->root_item.drop_progress, 0,
4302 sizeof(root->root_item.drop_progress));
4303 root->root_item.drop_level = 0;
4304 btrfs_set_root_refs(&root->root_item, 0);
4305 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4306 &root->root_key, &root->root_item);
4307
4308 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4309 if (err)
4310 return err;
4311 return ret;
4312 }
4313
4314 /*
4315 * recover relocation interrupted by system crash.
4316 *
4317 * this function resumes merging reloc trees with corresponding fs trees.
4318 * this is important for keeping the sharing of tree blocks
4319 */
4320 int btrfs_recover_relocation(struct btrfs_root *root)
4321 {
4322 LIST_HEAD(reloc_roots);
4323 struct btrfs_key key;
4324 struct btrfs_root *fs_root;
4325 struct btrfs_root *reloc_root;
4326 struct btrfs_path *path;
4327 struct extent_buffer *leaf;
4328 struct reloc_control *rc = NULL;
4329 struct btrfs_trans_handle *trans;
4330 int ret;
4331 int err = 0;
4332
4333 path = btrfs_alloc_path();
4334 if (!path)
4335 return -ENOMEM;
4336 path->reada = -1;
4337
4338 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4339 key.type = BTRFS_ROOT_ITEM_KEY;
4340 key.offset = (u64)-1;
4341
4342 while (1) {
4343 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4344 path, 0, 0);
4345 if (ret < 0) {
4346 err = ret;
4347 goto out;
4348 }
4349 if (ret > 0) {
4350 if (path->slots[0] == 0)
4351 break;
4352 path->slots[0]--;
4353 }
4354 leaf = path->nodes[0];
4355 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4356 btrfs_release_path(path);
4357
4358 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4359 key.type != BTRFS_ROOT_ITEM_KEY)
4360 break;
4361
4362 reloc_root = btrfs_read_fs_root(root, &key);
4363 if (IS_ERR(reloc_root)) {
4364 err = PTR_ERR(reloc_root);
4365 goto out;
4366 }
4367
4368 list_add(&reloc_root->root_list, &reloc_roots);
4369
4370 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4371 fs_root = read_fs_root(root->fs_info,
4372 reloc_root->root_key.offset);
4373 if (IS_ERR(fs_root)) {
4374 ret = PTR_ERR(fs_root);
4375 if (ret != -ENOENT) {
4376 err = ret;
4377 goto out;
4378 }
4379 ret = mark_garbage_root(reloc_root);
4380 if (ret < 0) {
4381 err = ret;
4382 goto out;
4383 }
4384 }
4385 }
4386
4387 if (key.offset == 0)
4388 break;
4389
4390 key.offset--;
4391 }
4392 btrfs_release_path(path);
4393
4394 if (list_empty(&reloc_roots))
4395 goto out;
4396
4397 rc = alloc_reloc_control(root->fs_info);
4398 if (!rc) {
4399 err = -ENOMEM;
4400 goto out;
4401 }
4402
4403 rc->extent_root = root->fs_info->extent_root;
4404
4405 set_reloc_control(rc);
4406
4407 trans = btrfs_join_transaction(rc->extent_root);
4408 if (IS_ERR(trans)) {
4409 unset_reloc_control(rc);
4410 err = PTR_ERR(trans);
4411 goto out_free;
4412 }
4413
4414 rc->merge_reloc_tree = 1;
4415
4416 while (!list_empty(&reloc_roots)) {
4417 reloc_root = list_entry(reloc_roots.next,
4418 struct btrfs_root, root_list);
4419 list_del(&reloc_root->root_list);
4420
4421 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4422 list_add_tail(&reloc_root->root_list,
4423 &rc->reloc_roots);
4424 continue;
4425 }
4426
4427 fs_root = read_fs_root(root->fs_info,
4428 reloc_root->root_key.offset);
4429 if (IS_ERR(fs_root)) {
4430 err = PTR_ERR(fs_root);
4431 goto out_free;
4432 }
4433
4434 err = __add_reloc_root(reloc_root);
4435 BUG_ON(err < 0); /* -ENOMEM or logic error */
4436 fs_root->reloc_root = reloc_root;
4437 }
4438
4439 err = btrfs_commit_transaction(trans, rc->extent_root);
4440 if (err)
4441 goto out_free;
4442
4443 merge_reloc_roots(rc);
4444
4445 unset_reloc_control(rc);
4446
4447 trans = btrfs_join_transaction(rc->extent_root);
4448 if (IS_ERR(trans))
4449 err = PTR_ERR(trans);
4450 else
4451 err = btrfs_commit_transaction(trans, rc->extent_root);
4452 out_free:
4453 kfree(rc);
4454 out:
4455 if (!list_empty(&reloc_roots))
4456 free_reloc_roots(&reloc_roots);
4457
4458 btrfs_free_path(path);
4459
4460 if (err == 0) {
4461 /* cleanup orphan inode in data relocation tree */
4462 fs_root = read_fs_root(root->fs_info,
4463 BTRFS_DATA_RELOC_TREE_OBJECTID);
4464 if (IS_ERR(fs_root))
4465 err = PTR_ERR(fs_root);
4466 else
4467 err = btrfs_orphan_cleanup(fs_root);
4468 }
4469 return err;
4470 }
4471
4472 /*
4473 * helper to add ordered checksum for data relocation.
4474 *
4475 * cloning checksum properly handles the nodatasum extents.
4476 * it also saves CPU time to re-calculate the checksum.
4477 */
4478 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4479 {
4480 struct btrfs_ordered_sum *sums;
4481 struct btrfs_ordered_extent *ordered;
4482 struct btrfs_root *root = BTRFS_I(inode)->root;
4483 int ret;
4484 u64 disk_bytenr;
4485 u64 new_bytenr;
4486 LIST_HEAD(list);
4487
4488 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4489 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4490
4491 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4492 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4493 disk_bytenr + len - 1, &list, 0);
4494 if (ret)
4495 goto out;
4496
4497 while (!list_empty(&list)) {
4498 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4499 list_del_init(&sums->list);
4500
4501 /*
4502 * We need to offset the new_bytenr based on where the csum is.
4503 * We need to do this because we will read in entire prealloc
4504 * extents but we may have written to say the middle of the
4505 * prealloc extent, so we need to make sure the csum goes with
4506 * the right disk offset.
4507 *
4508 * We can do this because the data reloc inode refers strictly
4509 * to the on disk bytes, so we don't have to worry about
4510 * disk_len vs real len like with real inodes since it's all
4511 * disk length.
4512 */
4513 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4514 sums->bytenr = new_bytenr;
4515
4516 btrfs_add_ordered_sum(inode, ordered, sums);
4517 }
4518 out:
4519 btrfs_put_ordered_extent(ordered);
4520 return ret;
4521 }
4522
4523 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4524 struct btrfs_root *root, struct extent_buffer *buf,
4525 struct extent_buffer *cow)
4526 {
4527 struct reloc_control *rc;
4528 struct backref_node *node;
4529 int first_cow = 0;
4530 int level;
4531 int ret = 0;
4532
4533 rc = root->fs_info->reloc_ctl;
4534 if (!rc)
4535 return 0;
4536
4537 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4538 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4539
4540 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4541 if (buf == root->node)
4542 __update_reloc_root(root, cow->start);
4543 }
4544
4545 level = btrfs_header_level(buf);
4546 if (btrfs_header_generation(buf) <=
4547 btrfs_root_last_snapshot(&root->root_item))
4548 first_cow = 1;
4549
4550 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4551 rc->create_reloc_tree) {
4552 WARN_ON(!first_cow && level == 0);
4553
4554 node = rc->backref_cache.path[level];
4555 BUG_ON(node->bytenr != buf->start &&
4556 node->new_bytenr != buf->start);
4557
4558 drop_node_buffer(node);
4559 extent_buffer_get(cow);
4560 node->eb = cow;
4561 node->new_bytenr = cow->start;
4562
4563 if (!node->pending) {
4564 list_move_tail(&node->list,
4565 &rc->backref_cache.pending[level]);
4566 node->pending = 1;
4567 }
4568
4569 if (first_cow)
4570 __mark_block_processed(rc, node);
4571
4572 if (first_cow && level > 0)
4573 rc->nodes_relocated += buf->len;
4574 }
4575
4576 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4577 ret = replace_file_extents(trans, rc, root, cow);
4578 return ret;
4579 }
4580
4581 /*
4582 * called before creating snapshot. it calculates metadata reservation
4583 * requried for relocating tree blocks in the snapshot
4584 */
4585 void btrfs_reloc_pre_snapshot(struct btrfs_trans_handle *trans,
4586 struct btrfs_pending_snapshot *pending,
4587 u64 *bytes_to_reserve)
4588 {
4589 struct btrfs_root *root;
4590 struct reloc_control *rc;
4591
4592 root = pending->root;
4593 if (!root->reloc_root)
4594 return;
4595
4596 rc = root->fs_info->reloc_ctl;
4597 if (!rc->merge_reloc_tree)
4598 return;
4599
4600 root = root->reloc_root;
4601 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4602 /*
4603 * relocation is in the stage of merging trees. the space
4604 * used by merging a reloc tree is twice the size of
4605 * relocated tree nodes in the worst case. half for cowing
4606 * the reloc tree, half for cowing the fs tree. the space
4607 * used by cowing the reloc tree will be freed after the
4608 * tree is dropped. if we create snapshot, cowing the fs
4609 * tree may use more space than it frees. so we need
4610 * reserve extra space.
4611 */
4612 *bytes_to_reserve += rc->nodes_relocated;
4613 }
4614
4615 /*
4616 * called after snapshot is created. migrate block reservation
4617 * and create reloc root for the newly created snapshot
4618 */
4619 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4620 struct btrfs_pending_snapshot *pending)
4621 {
4622 struct btrfs_root *root = pending->root;
4623 struct btrfs_root *reloc_root;
4624 struct btrfs_root *new_root;
4625 struct reloc_control *rc;
4626 int ret;
4627
4628 if (!root->reloc_root)
4629 return 0;
4630
4631 rc = root->fs_info->reloc_ctl;
4632 rc->merging_rsv_size += rc->nodes_relocated;
4633
4634 if (rc->merge_reloc_tree) {
4635 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4636 rc->block_rsv,
4637 rc->nodes_relocated);
4638 if (ret)
4639 return ret;
4640 }
4641
4642 new_root = pending->snap;
4643 reloc_root = create_reloc_root(trans, root->reloc_root,
4644 new_root->root_key.objectid);
4645 if (IS_ERR(reloc_root))
4646 return PTR_ERR(reloc_root);
4647
4648 ret = __add_reloc_root(reloc_root);
4649 BUG_ON(ret < 0);
4650 new_root->reloc_root = reloc_root;
4651
4652 if (rc->create_reloc_tree)
4653 ret = clone_backref_node(trans, rc, root, reloc_root);
4654 return ret;
4655 }
Linux with added FPC-III support