?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
btrfs: avoid blocking open_ctree from cleaner_kthread
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blob0477dca154ed084b7634bae4fbf4938f0fa223b7
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 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
580 return 1;
581 return 0;
582 }
583
584 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
585 u64 root_objectid)
586 {
587 struct btrfs_key key;
588
589 key.objectid = root_objectid;
590 key.type = BTRFS_ROOT_ITEM_KEY;
591 if (is_cowonly_root(root_objectid))
592 key.offset = 0;
593 else
594 key.offset = (u64)-1;
595
596 return btrfs_get_fs_root(fs_info, &key, false);
597 }
598
599 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
600 static noinline_for_stack
601 struct btrfs_root *find_tree_root(struct reloc_control *rc,
602 struct extent_buffer *leaf,
603 struct btrfs_extent_ref_v0 *ref0)
604 {
605 struct btrfs_root *root;
606 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
607 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
608
609 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
610
611 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
612 BUG_ON(IS_ERR(root));
613
614 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
615 generation != btrfs_root_generation(&root->root_item))
616 return NULL;
617
618 return root;
619 }
620 #endif
621
622 static noinline_for_stack
623 int find_inline_backref(struct extent_buffer *leaf, int slot,
624 unsigned long *ptr, unsigned long *end)
625 {
626 struct btrfs_key key;
627 struct btrfs_extent_item *ei;
628 struct btrfs_tree_block_info *bi;
629 u32 item_size;
630
631 btrfs_item_key_to_cpu(leaf, &key, slot);
632
633 item_size = btrfs_item_size_nr(leaf, slot);
634 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
635 if (item_size < sizeof(*ei)) {
636 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
637 return 1;
638 }
639 #endif
640 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
641 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
642 BTRFS_EXTENT_FLAG_TREE_BLOCK));
643
644 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
645 item_size <= sizeof(*ei) + sizeof(*bi)) {
646 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
647 return 1;
648 }
649 if (key.type == BTRFS_METADATA_ITEM_KEY &&
650 item_size <= sizeof(*ei)) {
651 WARN_ON(item_size < sizeof(*ei));
652 return 1;
653 }
654
655 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
656 bi = (struct btrfs_tree_block_info *)(ei + 1);
657 *ptr = (unsigned long)(bi + 1);
658 } else {
659 *ptr = (unsigned long)(ei + 1);
660 }
661 *end = (unsigned long)ei + item_size;
662 return 0;
663 }
664
665 /*
666 * build backref tree for a given tree block. root of the backref tree
667 * corresponds the tree block, leaves of the backref tree correspond
668 * roots of b-trees that reference the tree block.
669 *
670 * the basic idea of this function is check backrefs of a given block
671 * to find upper level blocks that reference the block, and then check
672 * backrefs of these upper level blocks recursively. the recursion stop
673 * when tree root is reached or backrefs for the block is cached.
674 *
675 * NOTE: if we find backrefs for a block are cached, we know backrefs
676 * for all upper level blocks that directly/indirectly reference the
677 * block are also cached.
678 */
679 static noinline_for_stack
680 struct backref_node *build_backref_tree(struct reloc_control *rc,
681 struct btrfs_key *node_key,
682 int level, u64 bytenr)
683 {
684 struct backref_cache *cache = &rc->backref_cache;
685 struct btrfs_path *path1;
686 struct btrfs_path *path2;
687 struct extent_buffer *eb;
688 struct btrfs_root *root;
689 struct backref_node *cur;
690 struct backref_node *upper;
691 struct backref_node *lower;
692 struct backref_node *node = NULL;
693 struct backref_node *exist = NULL;
694 struct backref_edge *edge;
695 struct rb_node *rb_node;
696 struct btrfs_key key;
697 unsigned long end;
698 unsigned long ptr;
699 LIST_HEAD(list);
700 LIST_HEAD(useless);
701 int cowonly;
702 int ret;
703 int err = 0;
704 bool need_check = true;
705
706 path1 = btrfs_alloc_path();
707 path2 = btrfs_alloc_path();
708 if (!path1 || !path2) {
709 err = -ENOMEM;
710 goto out;
711 }
712 path1->reada = READA_FORWARD;
713 path2->reada = READA_FORWARD;
714
715 node = alloc_backref_node(cache);
716 if (!node) {
717 err = -ENOMEM;
718 goto out;
719 }
720
721 node->bytenr = bytenr;
722 node->level = level;
723 node->lowest = 1;
724 cur = node;
725 again:
726 end = 0;
727 ptr = 0;
728 key.objectid = cur->bytenr;
729 key.type = BTRFS_METADATA_ITEM_KEY;
730 key.offset = (u64)-1;
731
732 path1->search_commit_root = 1;
733 path1->skip_locking = 1;
734 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
735 0, 0);
736 if (ret < 0) {
737 err = ret;
738 goto out;
739 }
740 ASSERT(ret);
741 ASSERT(path1->slots[0]);
742
743 path1->slots[0]--;
744
745 WARN_ON(cur->checked);
746 if (!list_empty(&cur->upper)) {
747 /*
748 * the backref was added previously when processing
749 * backref of type BTRFS_TREE_BLOCK_REF_KEY
750 */
751 ASSERT(list_is_singular(&cur->upper));
752 edge = list_entry(cur->upper.next, struct backref_edge,
753 list[LOWER]);
754 ASSERT(list_empty(&edge->list[UPPER]));
755 exist = edge->node[UPPER];
756 /*
757 * add the upper level block to pending list if we need
758 * check its backrefs
759 */
760 if (!exist->checked)
761 list_add_tail(&edge->list[UPPER], &list);
762 } else {
763 exist = NULL;
764 }
765
766 while (1) {
767 cond_resched();
768 eb = path1->nodes[0];
769
770 if (ptr >= end) {
771 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
772 ret = btrfs_next_leaf(rc->extent_root, path1);
773 if (ret < 0) {
774 err = ret;
775 goto out;
776 }
777 if (ret > 0)
778 break;
779 eb = path1->nodes[0];
780 }
781
782 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
783 if (key.objectid != cur->bytenr) {
784 WARN_ON(exist);
785 break;
786 }
787
788 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
789 key.type == BTRFS_METADATA_ITEM_KEY) {
790 ret = find_inline_backref(eb, path1->slots[0],
791 &ptr, &end);
792 if (ret)
793 goto next;
794 }
795 }
796
797 if (ptr < end) {
798 /* update key for inline back ref */
799 struct btrfs_extent_inline_ref *iref;
800 iref = (struct btrfs_extent_inline_ref *)ptr;
801 key.type = btrfs_extent_inline_ref_type(eb, iref);
802 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
803 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
804 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
805 }
806
807 if (exist &&
808 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
809 exist->owner == key.offset) ||
810 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
811 exist->bytenr == key.offset))) {
812 exist = NULL;
813 goto next;
814 }
815
816 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
817 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
818 key.type == BTRFS_EXTENT_REF_V0_KEY) {
819 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
820 struct btrfs_extent_ref_v0 *ref0;
821 ref0 = btrfs_item_ptr(eb, path1->slots[0],
822 struct btrfs_extent_ref_v0);
823 if (key.objectid == key.offset) {
824 root = find_tree_root(rc, eb, ref0);
825 if (root && !should_ignore_root(root))
826 cur->root = root;
827 else
828 list_add(&cur->list, &useless);
829 break;
830 }
831 if (is_cowonly_root(btrfs_ref_root_v0(eb,
832 ref0)))
833 cur->cowonly = 1;
834 }
835 #else
836 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
837 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
838 #endif
839 if (key.objectid == key.offset) {
840 /*
841 * only root blocks of reloc trees use
842 * backref of this type.
843 */
844 root = find_reloc_root(rc, cur->bytenr);
845 ASSERT(root);
846 cur->root = root;
847 break;
848 }
849
850 edge = alloc_backref_edge(cache);
851 if (!edge) {
852 err = -ENOMEM;
853 goto out;
854 }
855 rb_node = tree_search(&cache->rb_root, key.offset);
856 if (!rb_node) {
857 upper = alloc_backref_node(cache);
858 if (!upper) {
859 free_backref_edge(cache, edge);
860 err = -ENOMEM;
861 goto out;
862 }
863 upper->bytenr = key.offset;
864 upper->level = cur->level + 1;
865 /*
866 * backrefs for the upper level block isn't
867 * cached, add the block to pending list
868 */
869 list_add_tail(&edge->list[UPPER], &list);
870 } else {
871 upper = rb_entry(rb_node, struct backref_node,
872 rb_node);
873 ASSERT(upper->checked);
874 INIT_LIST_HEAD(&edge->list[UPPER]);
875 }
876 list_add_tail(&edge->list[LOWER], &cur->upper);
877 edge->node[LOWER] = cur;
878 edge->node[UPPER] = upper;
879
880 goto next;
881 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
882 goto next;
883 }
884
885 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
886 root = read_fs_root(rc->extent_root->fs_info, key.offset);
887 if (IS_ERR(root)) {
888 err = PTR_ERR(root);
889 goto out;
890 }
891
892 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
893 cur->cowonly = 1;
894
895 if (btrfs_root_level(&root->root_item) == cur->level) {
896 /* tree root */
897 ASSERT(btrfs_root_bytenr(&root->root_item) ==
898 cur->bytenr);
899 if (should_ignore_root(root))
900 list_add(&cur->list, &useless);
901 else
902 cur->root = root;
903 break;
904 }
905
906 level = cur->level + 1;
907
908 /*
909 * searching the tree to find upper level blocks
910 * reference the block.
911 */
912 path2->search_commit_root = 1;
913 path2->skip_locking = 1;
914 path2->lowest_level = level;
915 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
916 path2->lowest_level = 0;
917 if (ret < 0) {
918 err = ret;
919 goto out;
920 }
921 if (ret > 0 && path2->slots[level] > 0)
922 path2->slots[level]--;
923
924 eb = path2->nodes[level];
925 WARN_ON(btrfs_node_blockptr(eb, path2->slots[level]) !=
926 cur->bytenr);
927
928 lower = cur;
929 need_check = true;
930 for (; level < BTRFS_MAX_LEVEL; level++) {
931 if (!path2->nodes[level]) {
932 ASSERT(btrfs_root_bytenr(&root->root_item) ==
933 lower->bytenr);
934 if (should_ignore_root(root))
935 list_add(&lower->list, &useless);
936 else
937 lower->root = root;
938 break;
939 }
940
941 edge = alloc_backref_edge(cache);
942 if (!edge) {
943 err = -ENOMEM;
944 goto out;
945 }
946
947 eb = path2->nodes[level];
948 rb_node = tree_search(&cache->rb_root, eb->start);
949 if (!rb_node) {
950 upper = alloc_backref_node(cache);
951 if (!upper) {
952 free_backref_edge(cache, edge);
953 err = -ENOMEM;
954 goto out;
955 }
956 upper->bytenr = eb->start;
957 upper->owner = btrfs_header_owner(eb);
958 upper->level = lower->level + 1;
959 if (!test_bit(BTRFS_ROOT_REF_COWS,
960 &root->state))
961 upper->cowonly = 1;
962
963 /*
964 * if we know the block isn't shared
965 * we can void checking its backrefs.
966 */
967 if (btrfs_block_can_be_shared(root, eb))
968 upper->checked = 0;
969 else
970 upper->checked = 1;
971
972 /*
973 * add the block to pending list if we
974 * need check its backrefs, we only do this once
975 * while walking up a tree as we will catch
976 * anything else later on.
977 */
978 if (!upper->checked && need_check) {
979 need_check = false;
980 list_add_tail(&edge->list[UPPER],
981 &list);
982 } else {
983 if (upper->checked)
984 need_check = true;
985 INIT_LIST_HEAD(&edge->list[UPPER]);
986 }
987 } else {
988 upper = rb_entry(rb_node, struct backref_node,
989 rb_node);
990 ASSERT(upper->checked);
991 INIT_LIST_HEAD(&edge->list[UPPER]);
992 if (!upper->owner)
993 upper->owner = btrfs_header_owner(eb);
994 }
995 list_add_tail(&edge->list[LOWER], &lower->upper);
996 edge->node[LOWER] = lower;
997 edge->node[UPPER] = upper;
998
999 if (rb_node)
1000 break;
1001 lower = upper;
1002 upper = NULL;
1003 }
1004 btrfs_release_path(path2);
1005 next:
1006 if (ptr < end) {
1007 ptr += btrfs_extent_inline_ref_size(key.type);
1008 if (ptr >= end) {
1009 WARN_ON(ptr > end);
1010 ptr = 0;
1011 end = 0;
1012 }
1013 }
1014 if (ptr >= end)
1015 path1->slots[0]++;
1016 }
1017 btrfs_release_path(path1);
1018
1019 cur->checked = 1;
1020 WARN_ON(exist);
1021
1022 /* the pending list isn't empty, take the first block to process */
1023 if (!list_empty(&list)) {
1024 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1025 list_del_init(&edge->list[UPPER]);
1026 cur = edge->node[UPPER];
1027 goto again;
1028 }
1029
1030 /*
1031 * everything goes well, connect backref nodes and insert backref nodes
1032 * into the cache.
1033 */
1034 ASSERT(node->checked);
1035 cowonly = node->cowonly;
1036 if (!cowonly) {
1037 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1038 &node->rb_node);
1039 if (rb_node)
1040 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1041 list_add_tail(&node->lower, &cache->leaves);
1042 }
1043
1044 list_for_each_entry(edge, &node->upper, list[LOWER])
1045 list_add_tail(&edge->list[UPPER], &list);
1046
1047 while (!list_empty(&list)) {
1048 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1049 list_del_init(&edge->list[UPPER]);
1050 upper = edge->node[UPPER];
1051 if (upper->detached) {
1052 list_del(&edge->list[LOWER]);
1053 lower = edge->node[LOWER];
1054 free_backref_edge(cache, edge);
1055 if (list_empty(&lower->upper))
1056 list_add(&lower->list, &useless);
1057 continue;
1058 }
1059
1060 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1061 if (upper->lowest) {
1062 list_del_init(&upper->lower);
1063 upper->lowest = 0;
1064 }
1065
1066 list_add_tail(&edge->list[UPPER], &upper->lower);
1067 continue;
1068 }
1069
1070 if (!upper->checked) {
1071 /*
1072 * Still want to blow up for developers since this is a
1073 * logic bug.
1074 */
1075 ASSERT(0);
1076 err = -EINVAL;
1077 goto out;
1078 }
1079 if (cowonly != upper->cowonly) {
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084
1085 if (!cowonly) {
1086 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1087 &upper->rb_node);
1088 if (rb_node)
1089 backref_tree_panic(rb_node, -EEXIST,
1090 upper->bytenr);
1091 }
1092
1093 list_add_tail(&edge->list[UPPER], &upper->lower);
1094
1095 list_for_each_entry(edge, &upper->upper, list[LOWER])
1096 list_add_tail(&edge->list[UPPER], &list);
1097 }
1098 /*
1099 * process useless backref nodes. backref nodes for tree leaves
1100 * are deleted from the cache. backref nodes for upper level
1101 * tree blocks are left in the cache to avoid unnecessary backref
1102 * lookup.
1103 */
1104 while (!list_empty(&useless)) {
1105 upper = list_entry(useless.next, struct backref_node, list);
1106 list_del_init(&upper->list);
1107 ASSERT(list_empty(&upper->upper));
1108 if (upper == node)
1109 node = NULL;
1110 if (upper->lowest) {
1111 list_del_init(&upper->lower);
1112 upper->lowest = 0;
1113 }
1114 while (!list_empty(&upper->lower)) {
1115 edge = list_entry(upper->lower.next,
1116 struct backref_edge, list[UPPER]);
1117 list_del(&edge->list[UPPER]);
1118 list_del(&edge->list[LOWER]);
1119 lower = edge->node[LOWER];
1120 free_backref_edge(cache, edge);
1121
1122 if (list_empty(&lower->upper))
1123 list_add(&lower->list, &useless);
1124 }
1125 __mark_block_processed(rc, upper);
1126 if (upper->level > 0) {
1127 list_add(&upper->list, &cache->detached);
1128 upper->detached = 1;
1129 } else {
1130 rb_erase(&upper->rb_node, &cache->rb_root);
1131 free_backref_node(cache, upper);
1132 }
1133 }
1134 out:
1135 btrfs_free_path(path1);
1136 btrfs_free_path(path2);
1137 if (err) {
1138 while (!list_empty(&useless)) {
1139 lower = list_entry(useless.next,
1140 struct backref_node, list);
1141 list_del_init(&lower->list);
1142 }
1143 while (!list_empty(&list)) {
1144 edge = list_first_entry(&list, struct backref_edge,
1145 list[UPPER]);
1146 list_del(&edge->list[UPPER]);
1147 list_del(&edge->list[LOWER]);
1148 lower = edge->node[LOWER];
1149 upper = edge->node[UPPER];
1150 free_backref_edge(cache, edge);
1151
1152 /*
1153 * Lower is no longer linked to any upper backref nodes
1154 * and isn't in the cache, we can free it ourselves.
1155 */
1156 if (list_empty(&lower->upper) &&
1157 RB_EMPTY_NODE(&lower->rb_node))
1158 list_add(&lower->list, &useless);
1159
1160 if (!RB_EMPTY_NODE(&upper->rb_node))
1161 continue;
1162
1163 /* Add this guy's upper edges to the list to process */
1164 list_for_each_entry(edge, &upper->upper, list[LOWER])
1165 list_add_tail(&edge->list[UPPER], &list);
1166 if (list_empty(&upper->upper))
1167 list_add(&upper->list, &useless);
1168 }
1169
1170 while (!list_empty(&useless)) {
1171 lower = list_entry(useless.next,
1172 struct backref_node, list);
1173 list_del_init(&lower->list);
1174 free_backref_node(cache, lower);
1175 }
1176 return ERR_PTR(err);
1177 }
1178 ASSERT(!node || !node->detached);
1179 return node;
1180 }
1181
1182 /*
1183 * helper to add backref node for the newly created snapshot.
1184 * the backref node is created by cloning backref node that
1185 * corresponds to root of source tree
1186 */
1187 static int clone_backref_node(struct btrfs_trans_handle *trans,
1188 struct reloc_control *rc,
1189 struct btrfs_root *src,
1190 struct btrfs_root *dest)
1191 {
1192 struct btrfs_root *reloc_root = src->reloc_root;
1193 struct backref_cache *cache = &rc->backref_cache;
1194 struct backref_node *node = NULL;
1195 struct backref_node *new_node;
1196 struct backref_edge *edge;
1197 struct backref_edge *new_edge;
1198 struct rb_node *rb_node;
1199
1200 if (cache->last_trans > 0)
1201 update_backref_cache(trans, cache);
1202
1203 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1204 if (rb_node) {
1205 node = rb_entry(rb_node, struct backref_node, rb_node);
1206 if (node->detached)
1207 node = NULL;
1208 else
1209 BUG_ON(node->new_bytenr != reloc_root->node->start);
1210 }
1211
1212 if (!node) {
1213 rb_node = tree_search(&cache->rb_root,
1214 reloc_root->commit_root->start);
1215 if (rb_node) {
1216 node = rb_entry(rb_node, struct backref_node,
1217 rb_node);
1218 BUG_ON(node->detached);
1219 }
1220 }
1221
1222 if (!node)
1223 return 0;
1224
1225 new_node = alloc_backref_node(cache);
1226 if (!new_node)
1227 return -ENOMEM;
1228
1229 new_node->bytenr = dest->node->start;
1230 new_node->level = node->level;
1231 new_node->lowest = node->lowest;
1232 new_node->checked = 1;
1233 new_node->root = dest;
1234
1235 if (!node->lowest) {
1236 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1237 new_edge = alloc_backref_edge(cache);
1238 if (!new_edge)
1239 goto fail;
1240
1241 new_edge->node[UPPER] = new_node;
1242 new_edge->node[LOWER] = edge->node[LOWER];
1243 list_add_tail(&new_edge->list[UPPER],
1244 &new_node->lower);
1245 }
1246 } else {
1247 list_add_tail(&new_node->lower, &cache->leaves);
1248 }
1249
1250 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1251 &new_node->rb_node);
1252 if (rb_node)
1253 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1254
1255 if (!new_node->lowest) {
1256 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1257 list_add_tail(&new_edge->list[LOWER],
1258 &new_edge->node[LOWER]->upper);
1259 }
1260 }
1261 return 0;
1262 fail:
1263 while (!list_empty(&new_node->lower)) {
1264 new_edge = list_entry(new_node->lower.next,
1265 struct backref_edge, list[UPPER]);
1266 list_del(&new_edge->list[UPPER]);
1267 free_backref_edge(cache, new_edge);
1268 }
1269 free_backref_node(cache, new_node);
1270 return -ENOMEM;
1271 }
1272
1273 /*
1274 * helper to add 'address of tree root -> reloc tree' mapping
1275 */
1276 static int __must_check __add_reloc_root(struct btrfs_root *root)
1277 {
1278 struct rb_node *rb_node;
1279 struct mapping_node *node;
1280 struct reloc_control *rc = root->fs_info->reloc_ctl;
1281
1282 node = kmalloc(sizeof(*node), GFP_NOFS);
1283 if (!node)
1284 return -ENOMEM;
1285
1286 node->bytenr = root->node->start;
1287 node->data = root;
1288
1289 spin_lock(&rc->reloc_root_tree.lock);
1290 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1291 node->bytenr, &node->rb_node);
1292 spin_unlock(&rc->reloc_root_tree.lock);
1293 if (rb_node) {
1294 btrfs_panic(root->fs_info, -EEXIST, "Duplicate root found "
1295 "for start=%llu while inserting into relocation "
1296 "tree", node->bytenr);
1297 kfree(node);
1298 return -EEXIST;
1299 }
1300
1301 list_add_tail(&root->root_list, &rc->reloc_roots);
1302 return 0;
1303 }
1304
1305 /*
1306 * helper to delete the 'address of tree root -> reloc tree'
1307 * mapping
1308 */
1309 static void __del_reloc_root(struct btrfs_root *root)
1310 {
1311 struct rb_node *rb_node;
1312 struct mapping_node *node = NULL;
1313 struct reloc_control *rc = root->fs_info->reloc_ctl;
1314
1315 spin_lock(&rc->reloc_root_tree.lock);
1316 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1317 root->node->start);
1318 if (rb_node) {
1319 node = rb_entry(rb_node, struct mapping_node, rb_node);
1320 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1321 }
1322 spin_unlock(&rc->reloc_root_tree.lock);
1323
1324 if (!node)
1325 return;
1326 BUG_ON((struct btrfs_root *)node->data != root);
1327
1328 spin_lock(&root->fs_info->trans_lock);
1329 list_del_init(&root->root_list);
1330 spin_unlock(&root->fs_info->trans_lock);
1331 kfree(node);
1332 }
1333
1334 /*
1335 * helper to update the 'address of tree root -> reloc tree'
1336 * mapping
1337 */
1338 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1339 {
1340 struct rb_node *rb_node;
1341 struct mapping_node *node = NULL;
1342 struct reloc_control *rc = root->fs_info->reloc_ctl;
1343
1344 spin_lock(&rc->reloc_root_tree.lock);
1345 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1346 root->node->start);
1347 if (rb_node) {
1348 node = rb_entry(rb_node, struct mapping_node, rb_node);
1349 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1350 }
1351 spin_unlock(&rc->reloc_root_tree.lock);
1352
1353 if (!node)
1354 return 0;
1355 BUG_ON((struct btrfs_root *)node->data != root);
1356
1357 spin_lock(&rc->reloc_root_tree.lock);
1358 node->bytenr = new_bytenr;
1359 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1360 node->bytenr, &node->rb_node);
1361 spin_unlock(&rc->reloc_root_tree.lock);
1362 if (rb_node)
1363 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1364 return 0;
1365 }
1366
1367 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1368 struct btrfs_root *root, u64 objectid)
1369 {
1370 struct btrfs_root *reloc_root;
1371 struct extent_buffer *eb;
1372 struct btrfs_root_item *root_item;
1373 struct btrfs_key root_key;
1374 u64 last_snap = 0;
1375 int ret;
1376
1377 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1378 BUG_ON(!root_item);
1379
1380 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1381 root_key.type = BTRFS_ROOT_ITEM_KEY;
1382 root_key.offset = objectid;
1383
1384 if (root->root_key.objectid == objectid) {
1385 /* called by btrfs_init_reloc_root */
1386 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1387 BTRFS_TREE_RELOC_OBJECTID);
1388 BUG_ON(ret);
1389
1390 last_snap = btrfs_root_last_snapshot(&root->root_item);
1391 btrfs_set_root_last_snapshot(&root->root_item,
1392 trans->transid - 1);
1393 } else {
1394 /*
1395 * called by btrfs_reloc_post_snapshot_hook.
1396 * the source tree is a reloc tree, all tree blocks
1397 * modified after it was created have RELOC flag
1398 * set in their headers. so it's OK to not update
1399 * the 'last_snapshot'.
1400 */
1401 ret = btrfs_copy_root(trans, root, root->node, &eb,
1402 BTRFS_TREE_RELOC_OBJECTID);
1403 BUG_ON(ret);
1404 }
1405
1406 memcpy(root_item, &root->root_item, sizeof(*root_item));
1407 btrfs_set_root_bytenr(root_item, eb->start);
1408 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1409 btrfs_set_root_generation(root_item, trans->transid);
1410
1411 if (root->root_key.objectid == objectid) {
1412 btrfs_set_root_refs(root_item, 0);
1413 memset(&root_item->drop_progress, 0,
1414 sizeof(struct btrfs_disk_key));
1415 root_item->drop_level = 0;
1416 /*
1417 * abuse rtransid, it is safe because it is impossible to
1418 * receive data into a relocation tree.
1419 */
1420 btrfs_set_root_rtransid(root_item, last_snap);
1421 btrfs_set_root_otransid(root_item, trans->transid);
1422 }
1423
1424 btrfs_tree_unlock(eb);
1425 free_extent_buffer(eb);
1426
1427 ret = btrfs_insert_root(trans, root->fs_info->tree_root,
1428 &root_key, root_item);
1429 BUG_ON(ret);
1430 kfree(root_item);
1431
1432 reloc_root = btrfs_read_fs_root(root->fs_info->tree_root, &root_key);
1433 BUG_ON(IS_ERR(reloc_root));
1434 reloc_root->last_trans = trans->transid;
1435 return reloc_root;
1436 }
1437
1438 /*
1439 * create reloc tree for a given fs tree. reloc tree is just a
1440 * snapshot of the fs tree with special root objectid.
1441 */
1442 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1443 struct btrfs_root *root)
1444 {
1445 struct btrfs_root *reloc_root;
1446 struct reloc_control *rc = root->fs_info->reloc_ctl;
1447 struct btrfs_block_rsv *rsv;
1448 int clear_rsv = 0;
1449 int ret;
1450
1451 if (root->reloc_root) {
1452 reloc_root = root->reloc_root;
1453 reloc_root->last_trans = trans->transid;
1454 return 0;
1455 }
1456
1457 if (!rc || !rc->create_reloc_tree ||
1458 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1459 return 0;
1460
1461 if (!trans->reloc_reserved) {
1462 rsv = trans->block_rsv;
1463 trans->block_rsv = rc->block_rsv;
1464 clear_rsv = 1;
1465 }
1466 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1467 if (clear_rsv)
1468 trans->block_rsv = rsv;
1469
1470 ret = __add_reloc_root(reloc_root);
1471 BUG_ON(ret < 0);
1472 root->reloc_root = reloc_root;
1473 return 0;
1474 }
1475
1476 /*
1477 * update root item of reloc tree
1478 */
1479 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1480 struct btrfs_root *root)
1481 {
1482 struct btrfs_root *reloc_root;
1483 struct btrfs_root_item *root_item;
1484 int ret;
1485
1486 if (!root->reloc_root)
1487 goto out;
1488
1489 reloc_root = root->reloc_root;
1490 root_item = &reloc_root->root_item;
1491
1492 if (root->fs_info->reloc_ctl->merge_reloc_tree &&
1493 btrfs_root_refs(root_item) == 0) {
1494 root->reloc_root = NULL;
1495 __del_reloc_root(reloc_root);
1496 }
1497
1498 if (reloc_root->commit_root != reloc_root->node) {
1499 btrfs_set_root_node(root_item, reloc_root->node);
1500 free_extent_buffer(reloc_root->commit_root);
1501 reloc_root->commit_root = btrfs_root_node(reloc_root);
1502 }
1503
1504 ret = btrfs_update_root(trans, root->fs_info->tree_root,
1505 &reloc_root->root_key, root_item);
1506 BUG_ON(ret);
1507
1508 out:
1509 return 0;
1510 }
1511
1512 /*
1513 * helper to find first cached inode with inode number >= objectid
1514 * in a subvolume
1515 */
1516 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1517 {
1518 struct rb_node *node;
1519 struct rb_node *prev;
1520 struct btrfs_inode *entry;
1521 struct inode *inode;
1522
1523 spin_lock(&root->inode_lock);
1524 again:
1525 node = root->inode_tree.rb_node;
1526 prev = NULL;
1527 while (node) {
1528 prev = node;
1529 entry = rb_entry(node, struct btrfs_inode, rb_node);
1530
1531 if (objectid < btrfs_ino(&entry->vfs_inode))
1532 node = node->rb_left;
1533 else if (objectid > btrfs_ino(&entry->vfs_inode))
1534 node = node->rb_right;
1535 else
1536 break;
1537 }
1538 if (!node) {
1539 while (prev) {
1540 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1541 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1542 node = prev;
1543 break;
1544 }
1545 prev = rb_next(prev);
1546 }
1547 }
1548 while (node) {
1549 entry = rb_entry(node, struct btrfs_inode, rb_node);
1550 inode = igrab(&entry->vfs_inode);
1551 if (inode) {
1552 spin_unlock(&root->inode_lock);
1553 return inode;
1554 }
1555
1556 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1557 if (cond_resched_lock(&root->inode_lock))
1558 goto again;
1559
1560 node = rb_next(node);
1561 }
1562 spin_unlock(&root->inode_lock);
1563 return NULL;
1564 }
1565
1566 static int in_block_group(u64 bytenr,
1567 struct btrfs_block_group_cache *block_group)
1568 {
1569 if (bytenr >= block_group->key.objectid &&
1570 bytenr < block_group->key.objectid + block_group->key.offset)
1571 return 1;
1572 return 0;
1573 }
1574
1575 /*
1576 * get new location of data
1577 */
1578 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1579 u64 bytenr, u64 num_bytes)
1580 {
1581 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1582 struct btrfs_path *path;
1583 struct btrfs_file_extent_item *fi;
1584 struct extent_buffer *leaf;
1585 int ret;
1586
1587 path = btrfs_alloc_path();
1588 if (!path)
1589 return -ENOMEM;
1590
1591 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1592 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1593 bytenr, 0);
1594 if (ret < 0)
1595 goto out;
1596 if (ret > 0) {
1597 ret = -ENOENT;
1598 goto out;
1599 }
1600
1601 leaf = path->nodes[0];
1602 fi = btrfs_item_ptr(leaf, path->slots[0],
1603 struct btrfs_file_extent_item);
1604
1605 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1606 btrfs_file_extent_compression(leaf, fi) ||
1607 btrfs_file_extent_encryption(leaf, fi) ||
1608 btrfs_file_extent_other_encoding(leaf, fi));
1609
1610 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1611 ret = -EINVAL;
1612 goto out;
1613 }
1614
1615 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1616 ret = 0;
1617 out:
1618 btrfs_free_path(path);
1619 return ret;
1620 }
1621
1622 /*
1623 * update file extent items in the tree leaf to point to
1624 * the new locations.
1625 */
1626 static noinline_for_stack
1627 int replace_file_extents(struct btrfs_trans_handle *trans,
1628 struct reloc_control *rc,
1629 struct btrfs_root *root,
1630 struct extent_buffer *leaf)
1631 {
1632 struct btrfs_key key;
1633 struct btrfs_file_extent_item *fi;
1634 struct inode *inode = NULL;
1635 u64 parent;
1636 u64 bytenr;
1637 u64 new_bytenr = 0;
1638 u64 num_bytes;
1639 u64 end;
1640 u32 nritems;
1641 u32 i;
1642 int ret = 0;
1643 int first = 1;
1644 int dirty = 0;
1645
1646 if (rc->stage != UPDATE_DATA_PTRS)
1647 return 0;
1648
1649 /* reloc trees always use full backref */
1650 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1651 parent = leaf->start;
1652 else
1653 parent = 0;
1654
1655 nritems = btrfs_header_nritems(leaf);
1656 for (i = 0; i < nritems; i++) {
1657 cond_resched();
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
1660 continue;
1661 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1662 if (btrfs_file_extent_type(leaf, fi) ==
1663 BTRFS_FILE_EXTENT_INLINE)
1664 continue;
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1667 if (bytenr == 0)
1668 continue;
1669 if (!in_block_group(bytenr, rc->block_group))
1670 continue;
1671
1672 /*
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1675 */
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1677 if (first) {
1678 inode = find_next_inode(root, key.objectid);
1679 first = 0;
1680 } else if (inode && btrfs_ino(inode) < key.objectid) {
1681 btrfs_add_delayed_iput(inode);
1682 inode = find_next_inode(root, key.objectid);
1683 }
1684 if (inode && btrfs_ino(inode) == key.objectid) {
1685 end = key.offset +
1686 btrfs_file_extent_num_bytes(leaf, fi);
1687 WARN_ON(!IS_ALIGNED(key.offset,
1688 root->sectorsize));
1689 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
1690 end--;
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1692 key.offset, end);
1693 if (!ret)
1694 continue;
1695
1696 btrfs_drop_extent_cache(inode, key.offset, end,
1697 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1699 key.offset, end);
1700 }
1701 }
1702
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1704 bytenr, num_bytes);
1705 if (ret) {
1706 /*
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1709 */
1710 break;
1711 }
1712
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1714 dirty = 1;
1715
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1718 num_bytes, parent,
1719 btrfs_header_owner(leaf),
1720 key.objectid, key.offset);
1721 if (ret) {
1722 btrfs_abort_transaction(trans, root, ret);
1723 break;
1724 }
1725
1726 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1727 parent, btrfs_header_owner(leaf),
1728 key.objectid, key.offset);
1729 if (ret) {
1730 btrfs_abort_transaction(trans, root, ret);
1731 break;
1732 }
1733 }
1734 if (dirty)
1735 btrfs_mark_buffer_dirty(leaf);
1736 if (inode)
1737 btrfs_add_delayed_iput(inode);
1738 return ret;
1739 }
1740
1741 static noinline_for_stack
1742 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1743 struct btrfs_path *path, int level)
1744 {
1745 struct btrfs_disk_key key1;
1746 struct btrfs_disk_key key2;
1747 btrfs_node_key(eb, &key1, slot);
1748 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1749 return memcmp(&key1, &key2, sizeof(key1));
1750 }
1751
1752 /*
1753 * try to replace tree blocks in fs tree with the new blocks
1754 * in reloc tree. tree blocks haven't been modified since the
1755 * reloc tree was create can be replaced.
1756 *
1757 * if a block was replaced, level of the block + 1 is returned.
1758 * if no block got replaced, 0 is returned. if there are other
1759 * errors, a negative error number is returned.
1760 */
1761 static noinline_for_stack
1762 int replace_path(struct btrfs_trans_handle *trans,
1763 struct btrfs_root *dest, struct btrfs_root *src,
1764 struct btrfs_path *path, struct btrfs_key *next_key,
1765 int lowest_level, int max_level)
1766 {
1767 struct extent_buffer *eb;
1768 struct extent_buffer *parent;
1769 struct btrfs_key key;
1770 u64 old_bytenr;
1771 u64 new_bytenr;
1772 u64 old_ptr_gen;
1773 u64 new_ptr_gen;
1774 u64 last_snapshot;
1775 u32 blocksize;
1776 int cow = 0;
1777 int level;
1778 int ret;
1779 int slot;
1780
1781 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1782 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1783
1784 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1785 again:
1786 slot = path->slots[lowest_level];
1787 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1788
1789 eb = btrfs_lock_root_node(dest);
1790 btrfs_set_lock_blocking(eb);
1791 level = btrfs_header_level(eb);
1792
1793 if (level < lowest_level) {
1794 btrfs_tree_unlock(eb);
1795 free_extent_buffer(eb);
1796 return 0;
1797 }
1798
1799 if (cow) {
1800 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1801 BUG_ON(ret);
1802 }
1803 btrfs_set_lock_blocking(eb);
1804
1805 if (next_key) {
1806 next_key->objectid = (u64)-1;
1807 next_key->type = (u8)-1;
1808 next_key->offset = (u64)-1;
1809 }
1810
1811 parent = eb;
1812 while (1) {
1813 level = btrfs_header_level(parent);
1814 BUG_ON(level < lowest_level);
1815
1816 ret = btrfs_bin_search(parent, &key, level, &slot);
1817 if (ret && slot > 0)
1818 slot--;
1819
1820 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1821 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1822
1823 old_bytenr = btrfs_node_blockptr(parent, slot);
1824 blocksize = dest->nodesize;
1825 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1826
1827 if (level <= max_level) {
1828 eb = path->nodes[level];
1829 new_bytenr = btrfs_node_blockptr(eb,
1830 path->slots[level]);
1831 new_ptr_gen = btrfs_node_ptr_generation(eb,
1832 path->slots[level]);
1833 } else {
1834 new_bytenr = 0;
1835 new_ptr_gen = 0;
1836 }
1837
1838 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1839 ret = level;
1840 break;
1841 }
1842
1843 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1844 memcmp_node_keys(parent, slot, path, level)) {
1845 if (level <= lowest_level) {
1846 ret = 0;
1847 break;
1848 }
1849
1850 eb = read_tree_block(dest, old_bytenr, old_ptr_gen);
1851 if (IS_ERR(eb)) {
1852 ret = PTR_ERR(eb);
1853 break;
1854 } else if (!extent_buffer_uptodate(eb)) {
1855 ret = -EIO;
1856 free_extent_buffer(eb);
1857 break;
1858 }
1859 btrfs_tree_lock(eb);
1860 if (cow) {
1861 ret = btrfs_cow_block(trans, dest, eb, parent,
1862 slot, &eb);
1863 BUG_ON(ret);
1864 }
1865 btrfs_set_lock_blocking(eb);
1866
1867 btrfs_tree_unlock(parent);
1868 free_extent_buffer(parent);
1869
1870 parent = eb;
1871 continue;
1872 }
1873
1874 if (!cow) {
1875 btrfs_tree_unlock(parent);
1876 free_extent_buffer(parent);
1877 cow = 1;
1878 goto again;
1879 }
1880
1881 btrfs_node_key_to_cpu(path->nodes[level], &key,
1882 path->slots[level]);
1883 btrfs_release_path(path);
1884
1885 path->lowest_level = level;
1886 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1887 path->lowest_level = 0;
1888 BUG_ON(ret);
1889
1890 /*
1891 * swap blocks in fs tree and reloc tree.
1892 */
1893 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1894 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1895 btrfs_mark_buffer_dirty(parent);
1896
1897 btrfs_set_node_blockptr(path->nodes[level],
1898 path->slots[level], old_bytenr);
1899 btrfs_set_node_ptr_generation(path->nodes[level],
1900 path->slots[level], old_ptr_gen);
1901 btrfs_mark_buffer_dirty(path->nodes[level]);
1902
1903 ret = btrfs_inc_extent_ref(trans, src, old_bytenr, blocksize,
1904 path->nodes[level]->start,
1905 src->root_key.objectid, level - 1, 0);
1906 BUG_ON(ret);
1907 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr, blocksize,
1908 0, dest->root_key.objectid, level - 1,
1909 0);
1910 BUG_ON(ret);
1911
1912 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1913 path->nodes[level]->start,
1914 src->root_key.objectid, level - 1, 0);
1915 BUG_ON(ret);
1916
1917 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1918 0, dest->root_key.objectid, level - 1,
1919 0);
1920 BUG_ON(ret);
1921
1922 btrfs_unlock_up_safe(path, 0);
1923
1924 ret = level;
1925 break;
1926 }
1927 btrfs_tree_unlock(parent);
1928 free_extent_buffer(parent);
1929 return ret;
1930 }
1931
1932 /*
1933 * helper to find next relocated block in reloc tree
1934 */
1935 static noinline_for_stack
1936 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1937 int *level)
1938 {
1939 struct extent_buffer *eb;
1940 int i;
1941 u64 last_snapshot;
1942 u32 nritems;
1943
1944 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1945
1946 for (i = 0; i < *level; i++) {
1947 free_extent_buffer(path->nodes[i]);
1948 path->nodes[i] = NULL;
1949 }
1950
1951 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1952 eb = path->nodes[i];
1953 nritems = btrfs_header_nritems(eb);
1954 while (path->slots[i] + 1 < nritems) {
1955 path->slots[i]++;
1956 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1957 last_snapshot)
1958 continue;
1959
1960 *level = i;
1961 return 0;
1962 }
1963 free_extent_buffer(path->nodes[i]);
1964 path->nodes[i] = NULL;
1965 }
1966 return 1;
1967 }
1968
1969 /*
1970 * walk down reloc tree to find relocated block of lowest level
1971 */
1972 static noinline_for_stack
1973 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1974 int *level)
1975 {
1976 struct extent_buffer *eb = NULL;
1977 int i;
1978 u64 bytenr;
1979 u64 ptr_gen = 0;
1980 u64 last_snapshot;
1981 u32 nritems;
1982
1983 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1984
1985 for (i = *level; i > 0; i--) {
1986 eb = path->nodes[i];
1987 nritems = btrfs_header_nritems(eb);
1988 while (path->slots[i] < nritems) {
1989 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1990 if (ptr_gen > last_snapshot)
1991 break;
1992 path->slots[i]++;
1993 }
1994 if (path->slots[i] >= nritems) {
1995 if (i == *level)
1996 break;
1997 *level = i + 1;
1998 return 0;
1999 }
2000 if (i == 1) {
2001 *level = i;
2002 return 0;
2003 }
2004
2005 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2006 eb = read_tree_block(root, bytenr, ptr_gen);
2007 if (IS_ERR(eb)) {
2008 return PTR_ERR(eb);
2009 } else if (!extent_buffer_uptodate(eb)) {
2010 free_extent_buffer(eb);
2011 return -EIO;
2012 }
2013 BUG_ON(btrfs_header_level(eb) != i - 1);
2014 path->nodes[i - 1] = eb;
2015 path->slots[i - 1] = 0;
2016 }
2017 return 1;
2018 }
2019
2020 /*
2021 * invalidate extent cache for file extents whose key in range of
2022 * [min_key, max_key)
2023 */
2024 static int invalidate_extent_cache(struct btrfs_root *root,
2025 struct btrfs_key *min_key,
2026 struct btrfs_key *max_key)
2027 {
2028 struct inode *inode = NULL;
2029 u64 objectid;
2030 u64 start, end;
2031 u64 ino;
2032
2033 objectid = min_key->objectid;
2034 while (1) {
2035 cond_resched();
2036 iput(inode);
2037
2038 if (objectid > max_key->objectid)
2039 break;
2040
2041 inode = find_next_inode(root, objectid);
2042 if (!inode)
2043 break;
2044 ino = btrfs_ino(inode);
2045
2046 if (ino > max_key->objectid) {
2047 iput(inode);
2048 break;
2049 }
2050
2051 objectid = ino + 1;
2052 if (!S_ISREG(inode->i_mode))
2053 continue;
2054
2055 if (unlikely(min_key->objectid == ino)) {
2056 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2057 continue;
2058 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2059 start = 0;
2060 else {
2061 start = min_key->offset;
2062 WARN_ON(!IS_ALIGNED(start, root->sectorsize));
2063 }
2064 } else {
2065 start = 0;
2066 }
2067
2068 if (unlikely(max_key->objectid == ino)) {
2069 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2070 continue;
2071 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2072 end = (u64)-1;
2073 } else {
2074 if (max_key->offset == 0)
2075 continue;
2076 end = max_key->offset;
2077 WARN_ON(!IS_ALIGNED(end, root->sectorsize));
2078 end--;
2079 }
2080 } else {
2081 end = (u64)-1;
2082 }
2083
2084 /* the lock_extent waits for readpage to complete */
2085 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2086 btrfs_drop_extent_cache(inode, start, end, 1);
2087 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2088 }
2089 return 0;
2090 }
2091
2092 static int find_next_key(struct btrfs_path *path, int level,
2093 struct btrfs_key *key)
2094
2095 {
2096 while (level < BTRFS_MAX_LEVEL) {
2097 if (!path->nodes[level])
2098 break;
2099 if (path->slots[level] + 1 <
2100 btrfs_header_nritems(path->nodes[level])) {
2101 btrfs_node_key_to_cpu(path->nodes[level], key,
2102 path->slots[level] + 1);
2103 return 0;
2104 }
2105 level++;
2106 }
2107 return 1;
2108 }
2109
2110 /*
2111 * merge the relocated tree blocks in reloc tree with corresponding
2112 * fs tree.
2113 */
2114 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2115 struct btrfs_root *root)
2116 {
2117 LIST_HEAD(inode_list);
2118 struct btrfs_key key;
2119 struct btrfs_key next_key;
2120 struct btrfs_trans_handle *trans = NULL;
2121 struct btrfs_root *reloc_root;
2122 struct btrfs_root_item *root_item;
2123 struct btrfs_path *path;
2124 struct extent_buffer *leaf;
2125 int level;
2126 int max_level;
2127 int replaced = 0;
2128 int ret;
2129 int err = 0;
2130 u32 min_reserved;
2131
2132 path = btrfs_alloc_path();
2133 if (!path)
2134 return -ENOMEM;
2135 path->reada = READA_FORWARD;
2136
2137 reloc_root = root->reloc_root;
2138 root_item = &reloc_root->root_item;
2139
2140 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2141 level = btrfs_root_level(root_item);
2142 extent_buffer_get(reloc_root->node);
2143 path->nodes[level] = reloc_root->node;
2144 path->slots[level] = 0;
2145 } else {
2146 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2147
2148 level = root_item->drop_level;
2149 BUG_ON(level == 0);
2150 path->lowest_level = level;
2151 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2152 path->lowest_level = 0;
2153 if (ret < 0) {
2154 btrfs_free_path(path);
2155 return ret;
2156 }
2157
2158 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2159 path->slots[level]);
2160 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2161
2162 btrfs_unlock_up_safe(path, 0);
2163 }
2164
2165 min_reserved = root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2166 memset(&next_key, 0, sizeof(next_key));
2167
2168 while (1) {
2169 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2170 BTRFS_RESERVE_FLUSH_ALL);
2171 if (ret) {
2172 err = ret;
2173 goto out;
2174 }
2175 trans = btrfs_start_transaction(root, 0);
2176 if (IS_ERR(trans)) {
2177 err = PTR_ERR(trans);
2178 trans = NULL;
2179 goto out;
2180 }
2181 trans->block_rsv = rc->block_rsv;
2182
2183 replaced = 0;
2184 max_level = level;
2185
2186 ret = walk_down_reloc_tree(reloc_root, path, &level);
2187 if (ret < 0) {
2188 err = ret;
2189 goto out;
2190 }
2191 if (ret > 0)
2192 break;
2193
2194 if (!find_next_key(path, level, &key) &&
2195 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2196 ret = 0;
2197 } else {
2198 ret = replace_path(trans, root, reloc_root, path,
2199 &next_key, level, max_level);
2200 }
2201 if (ret < 0) {
2202 err = ret;
2203 goto out;
2204 }
2205
2206 if (ret > 0) {
2207 level = ret;
2208 btrfs_node_key_to_cpu(path->nodes[level], &key,
2209 path->slots[level]);
2210 replaced = 1;
2211 }
2212
2213 ret = walk_up_reloc_tree(reloc_root, path, &level);
2214 if (ret > 0)
2215 break;
2216
2217 BUG_ON(level == 0);
2218 /*
2219 * save the merging progress in the drop_progress.
2220 * this is OK since root refs == 1 in this case.
2221 */
2222 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2223 path->slots[level]);
2224 root_item->drop_level = level;
2225
2226 btrfs_end_transaction_throttle(trans, root);
2227 trans = NULL;
2228
2229 btrfs_btree_balance_dirty(root);
2230
2231 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2232 invalidate_extent_cache(root, &key, &next_key);
2233 }
2234
2235 /*
2236 * handle the case only one block in the fs tree need to be
2237 * relocated and the block is tree root.
2238 */
2239 leaf = btrfs_lock_root_node(root);
2240 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2241 btrfs_tree_unlock(leaf);
2242 free_extent_buffer(leaf);
2243 if (ret < 0)
2244 err = ret;
2245 out:
2246 btrfs_free_path(path);
2247
2248 if (err == 0) {
2249 memset(&root_item->drop_progress, 0,
2250 sizeof(root_item->drop_progress));
2251 root_item->drop_level = 0;
2252 btrfs_set_root_refs(root_item, 0);
2253 btrfs_update_reloc_root(trans, root);
2254 }
2255
2256 if (trans)
2257 btrfs_end_transaction_throttle(trans, root);
2258
2259 btrfs_btree_balance_dirty(root);
2260
2261 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2262 invalidate_extent_cache(root, &key, &next_key);
2263
2264 return err;
2265 }
2266
2267 static noinline_for_stack
2268 int prepare_to_merge(struct reloc_control *rc, int err)
2269 {
2270 struct btrfs_root *root = rc->extent_root;
2271 struct btrfs_root *reloc_root;
2272 struct btrfs_trans_handle *trans;
2273 LIST_HEAD(reloc_roots);
2274 u64 num_bytes = 0;
2275 int ret;
2276
2277 mutex_lock(&root->fs_info->reloc_mutex);
2278 rc->merging_rsv_size += root->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2279 rc->merging_rsv_size += rc->nodes_relocated * 2;
2280 mutex_unlock(&root->fs_info->reloc_mutex);
2281
2282 again:
2283 if (!err) {
2284 num_bytes = rc->merging_rsv_size;
2285 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2286 BTRFS_RESERVE_FLUSH_ALL);
2287 if (ret)
2288 err = ret;
2289 }
2290
2291 trans = btrfs_join_transaction(rc->extent_root);
2292 if (IS_ERR(trans)) {
2293 if (!err)
2294 btrfs_block_rsv_release(rc->extent_root,
2295 rc->block_rsv, num_bytes);
2296 return PTR_ERR(trans);
2297 }
2298
2299 if (!err) {
2300 if (num_bytes != rc->merging_rsv_size) {
2301 btrfs_end_transaction(trans, rc->extent_root);
2302 btrfs_block_rsv_release(rc->extent_root,
2303 rc->block_rsv, num_bytes);
2304 goto again;
2305 }
2306 }
2307
2308 rc->merge_reloc_tree = 1;
2309
2310 while (!list_empty(&rc->reloc_roots)) {
2311 reloc_root = list_entry(rc->reloc_roots.next,
2312 struct btrfs_root, root_list);
2313 list_del_init(&reloc_root->root_list);
2314
2315 root = read_fs_root(reloc_root->fs_info,
2316 reloc_root->root_key.offset);
2317 BUG_ON(IS_ERR(root));
2318 BUG_ON(root->reloc_root != reloc_root);
2319
2320 /*
2321 * set reference count to 1, so btrfs_recover_relocation
2322 * knows it should resumes merging
2323 */
2324 if (!err)
2325 btrfs_set_root_refs(&reloc_root->root_item, 1);
2326 btrfs_update_reloc_root(trans, root);
2327
2328 list_add(&reloc_root->root_list, &reloc_roots);
2329 }
2330
2331 list_splice(&reloc_roots, &rc->reloc_roots);
2332
2333 if (!err)
2334 btrfs_commit_transaction(trans, rc->extent_root);
2335 else
2336 btrfs_end_transaction(trans, rc->extent_root);
2337 return err;
2338 }
2339
2340 static noinline_for_stack
2341 void free_reloc_roots(struct list_head *list)
2342 {
2343 struct btrfs_root *reloc_root;
2344
2345 while (!list_empty(list)) {
2346 reloc_root = list_entry(list->next, struct btrfs_root,
2347 root_list);
2348 __del_reloc_root(reloc_root);
2349 }
2350 }
2351
2352 static noinline_for_stack
2353 void merge_reloc_roots(struct reloc_control *rc)
2354 {
2355 struct btrfs_root *root;
2356 struct btrfs_root *reloc_root;
2357 u64 last_snap;
2358 u64 otransid;
2359 u64 objectid;
2360 LIST_HEAD(reloc_roots);
2361 int found = 0;
2362 int ret = 0;
2363 again:
2364 root = rc->extent_root;
2365
2366 /*
2367 * this serializes us with btrfs_record_root_in_transaction,
2368 * we have to make sure nobody is in the middle of
2369 * adding their roots to the list while we are
2370 * doing this splice
2371 */
2372 mutex_lock(&root->fs_info->reloc_mutex);
2373 list_splice_init(&rc->reloc_roots, &reloc_roots);
2374 mutex_unlock(&root->fs_info->reloc_mutex);
2375
2376 while (!list_empty(&reloc_roots)) {
2377 found = 1;
2378 reloc_root = list_entry(reloc_roots.next,
2379 struct btrfs_root, root_list);
2380
2381 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2382 root = read_fs_root(reloc_root->fs_info,
2383 reloc_root->root_key.offset);
2384 BUG_ON(IS_ERR(root));
2385 BUG_ON(root->reloc_root != reloc_root);
2386
2387 ret = merge_reloc_root(rc, root);
2388 if (ret) {
2389 if (list_empty(&reloc_root->root_list))
2390 list_add_tail(&reloc_root->root_list,
2391 &reloc_roots);
2392 goto out;
2393 }
2394 } else {
2395 list_del_init(&reloc_root->root_list);
2396 }
2397
2398 /*
2399 * we keep the old last snapshot transid in rtranid when we
2400 * created the relocation tree.
2401 */
2402 last_snap = btrfs_root_rtransid(&reloc_root->root_item);
2403 otransid = btrfs_root_otransid(&reloc_root->root_item);
2404 objectid = reloc_root->root_key.offset;
2405
2406 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2407 if (ret < 0) {
2408 if (list_empty(&reloc_root->root_list))
2409 list_add_tail(&reloc_root->root_list,
2410 &reloc_roots);
2411 goto out;
2412 }
2413 }
2414
2415 if (found) {
2416 found = 0;
2417 goto again;
2418 }
2419 out:
2420 if (ret) {
2421 btrfs_handle_fs_error(root->fs_info, ret, NULL);
2422 if (!list_empty(&reloc_roots))
2423 free_reloc_roots(&reloc_roots);
2424
2425 /* new reloc root may be added */
2426 mutex_lock(&root->fs_info->reloc_mutex);
2427 list_splice_init(&rc->reloc_roots, &reloc_roots);
2428 mutex_unlock(&root->fs_info->reloc_mutex);
2429 if (!list_empty(&reloc_roots))
2430 free_reloc_roots(&reloc_roots);
2431 }
2432
2433 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2434 }
2435
2436 static void free_block_list(struct rb_root *blocks)
2437 {
2438 struct tree_block *block;
2439 struct rb_node *rb_node;
2440 while ((rb_node = rb_first(blocks))) {
2441 block = rb_entry(rb_node, struct tree_block, rb_node);
2442 rb_erase(rb_node, blocks);
2443 kfree(block);
2444 }
2445 }
2446
2447 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2448 struct btrfs_root *reloc_root)
2449 {
2450 struct btrfs_root *root;
2451
2452 if (reloc_root->last_trans == trans->transid)
2453 return 0;
2454
2455 root = read_fs_root(reloc_root->fs_info, reloc_root->root_key.offset);
2456 BUG_ON(IS_ERR(root));
2457 BUG_ON(root->reloc_root != reloc_root);
2458
2459 return btrfs_record_root_in_trans(trans, root);
2460 }
2461
2462 static noinline_for_stack
2463 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2464 struct reloc_control *rc,
2465 struct backref_node *node,
2466 struct backref_edge *edges[])
2467 {
2468 struct backref_node *next;
2469 struct btrfs_root *root;
2470 int index = 0;
2471
2472 next = node;
2473 while (1) {
2474 cond_resched();
2475 next = walk_up_backref(next, edges, &index);
2476 root = next->root;
2477 BUG_ON(!root);
2478 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2479
2480 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2481 record_reloc_root_in_trans(trans, root);
2482 break;
2483 }
2484
2485 btrfs_record_root_in_trans(trans, root);
2486 root = root->reloc_root;
2487
2488 if (next->new_bytenr != root->node->start) {
2489 BUG_ON(next->new_bytenr);
2490 BUG_ON(!list_empty(&next->list));
2491 next->new_bytenr = root->node->start;
2492 next->root = root;
2493 list_add_tail(&next->list,
2494 &rc->backref_cache.changed);
2495 __mark_block_processed(rc, next);
2496 break;
2497 }
2498
2499 WARN_ON(1);
2500 root = NULL;
2501 next = walk_down_backref(edges, &index);
2502 if (!next || next->level <= node->level)
2503 break;
2504 }
2505 if (!root)
2506 return NULL;
2507
2508 next = node;
2509 /* setup backref node path for btrfs_reloc_cow_block */
2510 while (1) {
2511 rc->backref_cache.path[next->level] = next;
2512 if (--index < 0)
2513 break;
2514 next = edges[index]->node[UPPER];
2515 }
2516 return root;
2517 }
2518
2519 /*
2520 * select a tree root for relocation. return NULL if the block
2521 * is reference counted. we should use do_relocation() in this
2522 * case. return a tree root pointer if the block isn't reference
2523 * counted. return -ENOENT if the block is root of reloc tree.
2524 */
2525 static noinline_for_stack
2526 struct btrfs_root *select_one_root(struct backref_node *node)
2527 {
2528 struct backref_node *next;
2529 struct btrfs_root *root;
2530 struct btrfs_root *fs_root = NULL;
2531 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2532 int index = 0;
2533
2534 next = node;
2535 while (1) {
2536 cond_resched();
2537 next = walk_up_backref(next, edges, &index);
2538 root = next->root;
2539 BUG_ON(!root);
2540
2541 /* no other choice for non-references counted tree */
2542 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2543 return root;
2544
2545 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2546 fs_root = root;
2547
2548 if (next != node)
2549 return NULL;
2550
2551 next = walk_down_backref(edges, &index);
2552 if (!next || next->level <= node->level)
2553 break;
2554 }
2555
2556 if (!fs_root)
2557 return ERR_PTR(-ENOENT);
2558 return fs_root;
2559 }
2560
2561 static noinline_for_stack
2562 u64 calcu_metadata_size(struct reloc_control *rc,
2563 struct backref_node *node, int reserve)
2564 {
2565 struct backref_node *next = node;
2566 struct backref_edge *edge;
2567 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2568 u64 num_bytes = 0;
2569 int index = 0;
2570
2571 BUG_ON(reserve && node->processed);
2572
2573 while (next) {
2574 cond_resched();
2575 while (1) {
2576 if (next->processed && (reserve || next != node))
2577 break;
2578
2579 num_bytes += rc->extent_root->nodesize;
2580
2581 if (list_empty(&next->upper))
2582 break;
2583
2584 edge = list_entry(next->upper.next,
2585 struct backref_edge, list[LOWER]);
2586 edges[index++] = edge;
2587 next = edge->node[UPPER];
2588 }
2589 next = walk_down_backref(edges, &index);
2590 }
2591 return num_bytes;
2592 }
2593
2594 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2595 struct reloc_control *rc,
2596 struct backref_node *node)
2597 {
2598 struct btrfs_root *root = rc->extent_root;
2599 u64 num_bytes;
2600 int ret;
2601 u64 tmp;
2602
2603 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2604
2605 trans->block_rsv = rc->block_rsv;
2606 rc->reserved_bytes += num_bytes;
2607 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2608 BTRFS_RESERVE_FLUSH_ALL);
2609 if (ret) {
2610 if (ret == -EAGAIN) {
2611 tmp = rc->extent_root->nodesize *
2612 RELOCATION_RESERVED_NODES;
2613 while (tmp <= rc->reserved_bytes)
2614 tmp <<= 1;
2615 /*
2616 * only one thread can access block_rsv at this point,
2617 * so we don't need hold lock to protect block_rsv.
2618 * we expand more reservation size here to allow enough
2619 * space for relocation and we will return earlier in
2620 * enospc case.
2621 */
2622 rc->block_rsv->size = tmp + rc->extent_root->nodesize *
2623 RELOCATION_RESERVED_NODES;
2624 }
2625 return ret;
2626 }
2627
2628 return 0;
2629 }
2630
2631 /*
2632 * relocate a block tree, and then update pointers in upper level
2633 * blocks that reference the block to point to the new location.
2634 *
2635 * if called by link_to_upper, the block has already been relocated.
2636 * in that case this function just updates pointers.
2637 */
2638 static int do_relocation(struct btrfs_trans_handle *trans,
2639 struct reloc_control *rc,
2640 struct backref_node *node,
2641 struct btrfs_key *key,
2642 struct btrfs_path *path, int lowest)
2643 {
2644 struct backref_node *upper;
2645 struct backref_edge *edge;
2646 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2647 struct btrfs_root *root;
2648 struct extent_buffer *eb;
2649 u32 blocksize;
2650 u64 bytenr;
2651 u64 generation;
2652 int slot;
2653 int ret;
2654 int err = 0;
2655
2656 BUG_ON(lowest && node->eb);
2657
2658 path->lowest_level = node->level + 1;
2659 rc->backref_cache.path[node->level] = node;
2660 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2661 cond_resched();
2662
2663 upper = edge->node[UPPER];
2664 root = select_reloc_root(trans, rc, upper, edges);
2665 BUG_ON(!root);
2666
2667 if (upper->eb && !upper->locked) {
2668 if (!lowest) {
2669 ret = btrfs_bin_search(upper->eb, key,
2670 upper->level, &slot);
2671 BUG_ON(ret);
2672 bytenr = btrfs_node_blockptr(upper->eb, slot);
2673 if (node->eb->start == bytenr)
2674 goto next;
2675 }
2676 drop_node_buffer(upper);
2677 }
2678
2679 if (!upper->eb) {
2680 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2681 if (ret < 0) {
2682 err = ret;
2683 break;
2684 }
2685 BUG_ON(ret > 0);
2686
2687 if (!upper->eb) {
2688 upper->eb = path->nodes[upper->level];
2689 path->nodes[upper->level] = NULL;
2690 } else {
2691 BUG_ON(upper->eb != path->nodes[upper->level]);
2692 }
2693
2694 upper->locked = 1;
2695 path->locks[upper->level] = 0;
2696
2697 slot = path->slots[upper->level];
2698 btrfs_release_path(path);
2699 } else {
2700 ret = btrfs_bin_search(upper->eb, key, upper->level,
2701 &slot);
2702 BUG_ON(ret);
2703 }
2704
2705 bytenr = btrfs_node_blockptr(upper->eb, slot);
2706 if (lowest) {
2707 BUG_ON(bytenr != node->bytenr);
2708 } else {
2709 if (node->eb->start == bytenr)
2710 goto next;
2711 }
2712
2713 blocksize = root->nodesize;
2714 generation = btrfs_node_ptr_generation(upper->eb, slot);
2715 eb = read_tree_block(root, bytenr, generation);
2716 if (IS_ERR(eb)) {
2717 err = PTR_ERR(eb);
2718 goto next;
2719 } else if (!extent_buffer_uptodate(eb)) {
2720 free_extent_buffer(eb);
2721 err = -EIO;
2722 goto next;
2723 }
2724 btrfs_tree_lock(eb);
2725 btrfs_set_lock_blocking(eb);
2726
2727 if (!node->eb) {
2728 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2729 slot, &eb);
2730 btrfs_tree_unlock(eb);
2731 free_extent_buffer(eb);
2732 if (ret < 0) {
2733 err = ret;
2734 goto next;
2735 }
2736 BUG_ON(node->eb != eb);
2737 } else {
2738 btrfs_set_node_blockptr(upper->eb, slot,
2739 node->eb->start);
2740 btrfs_set_node_ptr_generation(upper->eb, slot,
2741 trans->transid);
2742 btrfs_mark_buffer_dirty(upper->eb);
2743
2744 ret = btrfs_inc_extent_ref(trans, root,
2745 node->eb->start, blocksize,
2746 upper->eb->start,
2747 btrfs_header_owner(upper->eb),
2748 node->level, 0);
2749 BUG_ON(ret);
2750
2751 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2752 BUG_ON(ret);
2753 }
2754 next:
2755 if (!upper->pending)
2756 drop_node_buffer(upper);
2757 else
2758 unlock_node_buffer(upper);
2759 if (err)
2760 break;
2761 }
2762
2763 if (!err && node->pending) {
2764 drop_node_buffer(node);
2765 list_move_tail(&node->list, &rc->backref_cache.changed);
2766 node->pending = 0;
2767 }
2768
2769 path->lowest_level = 0;
2770 BUG_ON(err == -ENOSPC);
2771 return err;
2772 }
2773
2774 static int link_to_upper(struct btrfs_trans_handle *trans,
2775 struct reloc_control *rc,
2776 struct backref_node *node,
2777 struct btrfs_path *path)
2778 {
2779 struct btrfs_key key;
2780
2781 btrfs_node_key_to_cpu(node->eb, &key, 0);
2782 return do_relocation(trans, rc, node, &key, path, 0);
2783 }
2784
2785 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2786 struct reloc_control *rc,
2787 struct btrfs_path *path, int err)
2788 {
2789 LIST_HEAD(list);
2790 struct backref_cache *cache = &rc->backref_cache;
2791 struct backref_node *node;
2792 int level;
2793 int ret;
2794
2795 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2796 while (!list_empty(&cache->pending[level])) {
2797 node = list_entry(cache->pending[level].next,
2798 struct backref_node, list);
2799 list_move_tail(&node->list, &list);
2800 BUG_ON(!node->pending);
2801
2802 if (!err) {
2803 ret = link_to_upper(trans, rc, node, path);
2804 if (ret < 0)
2805 err = ret;
2806 }
2807 }
2808 list_splice_init(&list, &cache->pending[level]);
2809 }
2810 return err;
2811 }
2812
2813 static void mark_block_processed(struct reloc_control *rc,
2814 u64 bytenr, u32 blocksize)
2815 {
2816 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2817 EXTENT_DIRTY);
2818 }
2819
2820 static void __mark_block_processed(struct reloc_control *rc,
2821 struct backref_node *node)
2822 {
2823 u32 blocksize;
2824 if (node->level == 0 ||
2825 in_block_group(node->bytenr, rc->block_group)) {
2826 blocksize = rc->extent_root->nodesize;
2827 mark_block_processed(rc, node->bytenr, blocksize);
2828 }
2829 node->processed = 1;
2830 }
2831
2832 /*
2833 * mark a block and all blocks directly/indirectly reference the block
2834 * as processed.
2835 */
2836 static void update_processed_blocks(struct reloc_control *rc,
2837 struct backref_node *node)
2838 {
2839 struct backref_node *next = node;
2840 struct backref_edge *edge;
2841 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2842 int index = 0;
2843
2844 while (next) {
2845 cond_resched();
2846 while (1) {
2847 if (next->processed)
2848 break;
2849
2850 __mark_block_processed(rc, next);
2851
2852 if (list_empty(&next->upper))
2853 break;
2854
2855 edge = list_entry(next->upper.next,
2856 struct backref_edge, list[LOWER]);
2857 edges[index++] = edge;
2858 next = edge->node[UPPER];
2859 }
2860 next = walk_down_backref(edges, &index);
2861 }
2862 }
2863
2864 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2865 {
2866 u32 blocksize = rc->extent_root->nodesize;
2867
2868 if (test_range_bit(&rc->processed_blocks, bytenr,
2869 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2870 return 1;
2871 return 0;
2872 }
2873
2874 static int get_tree_block_key(struct reloc_control *rc,
2875 struct tree_block *block)
2876 {
2877 struct extent_buffer *eb;
2878
2879 BUG_ON(block->key_ready);
2880 eb = read_tree_block(rc->extent_root, block->bytenr,
2881 block->key.offset);
2882 if (IS_ERR(eb)) {
2883 return PTR_ERR(eb);
2884 } else if (!extent_buffer_uptodate(eb)) {
2885 free_extent_buffer(eb);
2886 return -EIO;
2887 }
2888 WARN_ON(btrfs_header_level(eb) != block->level);
2889 if (block->level == 0)
2890 btrfs_item_key_to_cpu(eb, &block->key, 0);
2891 else
2892 btrfs_node_key_to_cpu(eb, &block->key, 0);
2893 free_extent_buffer(eb);
2894 block->key_ready = 1;
2895 return 0;
2896 }
2897
2898 /*
2899 * helper function to relocate a tree block
2900 */
2901 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2902 struct reloc_control *rc,
2903 struct backref_node *node,
2904 struct btrfs_key *key,
2905 struct btrfs_path *path)
2906 {
2907 struct btrfs_root *root;
2908 int ret = 0;
2909
2910 if (!node)
2911 return 0;
2912
2913 BUG_ON(node->processed);
2914 root = select_one_root(node);
2915 if (root == ERR_PTR(-ENOENT)) {
2916 update_processed_blocks(rc, node);
2917 goto out;
2918 }
2919
2920 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2921 ret = reserve_metadata_space(trans, rc, node);
2922 if (ret)
2923 goto out;
2924 }
2925
2926 if (root) {
2927 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2928 BUG_ON(node->new_bytenr);
2929 BUG_ON(!list_empty(&node->list));
2930 btrfs_record_root_in_trans(trans, root);
2931 root = root->reloc_root;
2932 node->new_bytenr = root->node->start;
2933 node->root = root;
2934 list_add_tail(&node->list, &rc->backref_cache.changed);
2935 } else {
2936 path->lowest_level = node->level;
2937 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2938 btrfs_release_path(path);
2939 if (ret > 0)
2940 ret = 0;
2941 }
2942 if (!ret)
2943 update_processed_blocks(rc, node);
2944 } else {
2945 ret = do_relocation(trans, rc, node, key, path, 1);
2946 }
2947 out:
2948 if (ret || node->level == 0 || node->cowonly)
2949 remove_backref_node(&rc->backref_cache, node);
2950 return ret;
2951 }
2952
2953 /*
2954 * relocate a list of blocks
2955 */
2956 static noinline_for_stack
2957 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2958 struct reloc_control *rc, struct rb_root *blocks)
2959 {
2960 struct backref_node *node;
2961 struct btrfs_path *path;
2962 struct tree_block *block;
2963 struct rb_node *rb_node;
2964 int ret;
2965 int err = 0;
2966
2967 path = btrfs_alloc_path();
2968 if (!path) {
2969 err = -ENOMEM;
2970 goto out_free_blocks;
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 readahead_tree_block(rc->extent_root, block->bytenr);
2978 rb_node = rb_next(rb_node);
2979 }
2980
2981 rb_node = rb_first(blocks);
2982 while (rb_node) {
2983 block = rb_entry(rb_node, struct tree_block, rb_node);
2984 if (!block->key_ready) {
2985 err = get_tree_block_key(rc, block);
2986 if (err)
2987 goto out_free_path;
2988 }
2989 rb_node = rb_next(rb_node);
2990 }
2991
2992 rb_node = rb_first(blocks);
2993 while (rb_node) {
2994 block = rb_entry(rb_node, struct tree_block, rb_node);
2995
2996 node = build_backref_tree(rc, &block->key,
2997 block->level, block->bytenr);
2998 if (IS_ERR(node)) {
2999 err = PTR_ERR(node);
3000 goto out;
3001 }
3002
3003 ret = relocate_tree_block(trans, rc, node, &block->key,
3004 path);
3005 if (ret < 0) {
3006 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3007 err = ret;
3008 goto out;
3009 }
3010 rb_node = rb_next(rb_node);
3011 }
3012 out:
3013 err = finish_pending_nodes(trans, rc, path, err);
3014
3015 out_free_path:
3016 btrfs_free_path(path);
3017 out_free_blocks:
3018 free_block_list(blocks);
3019 return err;
3020 }
3021
3022 static noinline_for_stack
3023 int prealloc_file_extent_cluster(struct inode *inode,
3024 struct file_extent_cluster *cluster)
3025 {
3026 u64 alloc_hint = 0;
3027 u64 start;
3028 u64 end;
3029 u64 offset = BTRFS_I(inode)->index_cnt;
3030 u64 num_bytes;
3031 int nr = 0;
3032 int ret = 0;
3033
3034 BUG_ON(cluster->start != cluster->boundary[0]);
3035 inode_lock(inode);
3036
3037 ret = btrfs_check_data_free_space(inode, cluster->start,
3038 cluster->end + 1 - cluster->start);
3039 if (ret)
3040 goto out;
3041
3042 while (nr < cluster->nr) {
3043 start = cluster->boundary[nr] - offset;
3044 if (nr + 1 < cluster->nr)
3045 end = cluster->boundary[nr + 1] - 1 - offset;
3046 else
3047 end = cluster->end - offset;
3048
3049 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3050 num_bytes = end + 1 - start;
3051 ret = btrfs_prealloc_file_range(inode, 0, start,
3052 num_bytes, num_bytes,
3053 end + 1, &alloc_hint);
3054 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3055 if (ret)
3056 break;
3057 nr++;
3058 }
3059 btrfs_free_reserved_data_space(inode, cluster->start,
3060 cluster->end + 1 - cluster->start);
3061 out:
3062 inode_unlock(inode);
3063 return ret;
3064 }
3065
3066 static noinline_for_stack
3067 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3068 u64 block_start)
3069 {
3070 struct btrfs_root *root = BTRFS_I(inode)->root;
3071 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3072 struct extent_map *em;
3073 int ret = 0;
3074
3075 em = alloc_extent_map();
3076 if (!em)
3077 return -ENOMEM;
3078
3079 em->start = start;
3080 em->len = end + 1 - start;
3081 em->block_len = em->len;
3082 em->block_start = block_start;
3083 em->bdev = root->fs_info->fs_devices->latest_bdev;
3084 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3085
3086 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3087 while (1) {
3088 write_lock(&em_tree->lock);
3089 ret = add_extent_mapping(em_tree, em, 0);
3090 write_unlock(&em_tree->lock);
3091 if (ret != -EEXIST) {
3092 free_extent_map(em);
3093 break;
3094 }
3095 btrfs_drop_extent_cache(inode, start, end, 0);
3096 }
3097 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3098 return ret;
3099 }
3100
3101 static int relocate_file_extent_cluster(struct inode *inode,
3102 struct file_extent_cluster *cluster)
3103 {
3104 u64 page_start;
3105 u64 page_end;
3106 u64 offset = BTRFS_I(inode)->index_cnt;
3107 unsigned long index;
3108 unsigned long last_index;
3109 struct page *page;
3110 struct file_ra_state *ra;
3111 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3112 int nr = 0;
3113 int ret = 0;
3114
3115 if (!cluster->nr)
3116 return 0;
3117
3118 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3119 if (!ra)
3120 return -ENOMEM;
3121
3122 ret = prealloc_file_extent_cluster(inode, cluster);
3123 if (ret)
3124 goto out;
3125
3126 file_ra_state_init(ra, inode->i_mapping);
3127
3128 ret = setup_extent_mapping(inode, cluster->start - offset,
3129 cluster->end - offset, cluster->start);
3130 if (ret)
3131 goto out;
3132
3133 index = (cluster->start - offset) >> PAGE_SHIFT;
3134 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3135 while (index <= last_index) {
3136 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_SIZE);
3137 if (ret)
3138 goto out;
3139
3140 page = find_lock_page(inode->i_mapping, index);
3141 if (!page) {
3142 page_cache_sync_readahead(inode->i_mapping,
3143 ra, NULL, index,
3144 last_index + 1 - index);
3145 page = find_or_create_page(inode->i_mapping, index,
3146 mask);
3147 if (!page) {
3148 btrfs_delalloc_release_metadata(inode,
3149 PAGE_SIZE);
3150 ret = -ENOMEM;
3151 goto out;
3152 }
3153 }
3154
3155 if (PageReadahead(page)) {
3156 page_cache_async_readahead(inode->i_mapping,
3157 ra, NULL, page, index,
3158 last_index + 1 - index);
3159 }
3160
3161 if (!PageUptodate(page)) {
3162 btrfs_readpage(NULL, page);
3163 lock_page(page);
3164 if (!PageUptodate(page)) {
3165 unlock_page(page);
3166 put_page(page);
3167 btrfs_delalloc_release_metadata(inode,
3168 PAGE_SIZE);
3169 ret = -EIO;
3170 goto out;
3171 }
3172 }
3173
3174 page_start = page_offset(page);
3175 page_end = page_start + PAGE_SIZE - 1;
3176
3177 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3178
3179 set_page_extent_mapped(page);
3180
3181 if (nr < cluster->nr &&
3182 page_start + offset == cluster->boundary[nr]) {
3183 set_extent_bits(&BTRFS_I(inode)->io_tree,
3184 page_start, page_end,
3185 EXTENT_BOUNDARY);
3186 nr++;
3187 }
3188
3189 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL);
3190 set_page_dirty(page);
3191
3192 unlock_extent(&BTRFS_I(inode)->io_tree,
3193 page_start, page_end);
3194 unlock_page(page);
3195 put_page(page);
3196
3197 index++;
3198 balance_dirty_pages_ratelimited(inode->i_mapping);
3199 btrfs_throttle(BTRFS_I(inode)->root);
3200 }
3201 WARN_ON(nr != cluster->nr);
3202 out:
3203 kfree(ra);
3204 return ret;
3205 }
3206
3207 static noinline_for_stack
3208 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3209 struct file_extent_cluster *cluster)
3210 {
3211 int ret;
3212
3213 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3214 ret = relocate_file_extent_cluster(inode, cluster);
3215 if (ret)
3216 return ret;
3217 cluster->nr = 0;
3218 }
3219
3220 if (!cluster->nr)
3221 cluster->start = extent_key->objectid;
3222 else
3223 BUG_ON(cluster->nr >= MAX_EXTENTS);
3224 cluster->end = extent_key->objectid + extent_key->offset - 1;
3225 cluster->boundary[cluster->nr] = extent_key->objectid;
3226 cluster->nr++;
3227
3228 if (cluster->nr >= MAX_EXTENTS) {
3229 ret = relocate_file_extent_cluster(inode, cluster);
3230 if (ret)
3231 return ret;
3232 cluster->nr = 0;
3233 }
3234 return 0;
3235 }
3236
3237 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3238 static int get_ref_objectid_v0(struct reloc_control *rc,
3239 struct btrfs_path *path,
3240 struct btrfs_key *extent_key,
3241 u64 *ref_objectid, int *path_change)
3242 {
3243 struct btrfs_key key;
3244 struct extent_buffer *leaf;
3245 struct btrfs_extent_ref_v0 *ref0;
3246 int ret;
3247 int slot;
3248
3249 leaf = path->nodes[0];
3250 slot = path->slots[0];
3251 while (1) {
3252 if (slot >= btrfs_header_nritems(leaf)) {
3253 ret = btrfs_next_leaf(rc->extent_root, path);
3254 if (ret < 0)
3255 return ret;
3256 BUG_ON(ret > 0);
3257 leaf = path->nodes[0];
3258 slot = path->slots[0];
3259 if (path_change)
3260 *path_change = 1;
3261 }
3262 btrfs_item_key_to_cpu(leaf, &key, slot);
3263 if (key.objectid != extent_key->objectid)
3264 return -ENOENT;
3265
3266 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3267 slot++;
3268 continue;
3269 }
3270 ref0 = btrfs_item_ptr(leaf, slot,
3271 struct btrfs_extent_ref_v0);
3272 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3273 break;
3274 }
3275 return 0;
3276 }
3277 #endif
3278
3279 /*
3280 * helper to add a tree block to the list.
3281 * the major work is getting the generation and level of the block
3282 */
3283 static int add_tree_block(struct reloc_control *rc,
3284 struct btrfs_key *extent_key,
3285 struct btrfs_path *path,
3286 struct rb_root *blocks)
3287 {
3288 struct extent_buffer *eb;
3289 struct btrfs_extent_item *ei;
3290 struct btrfs_tree_block_info *bi;
3291 struct tree_block *block;
3292 struct rb_node *rb_node;
3293 u32 item_size;
3294 int level = -1;
3295 u64 generation;
3296
3297 eb = path->nodes[0];
3298 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3299
3300 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3301 item_size >= sizeof(*ei) + sizeof(*bi)) {
3302 ei = btrfs_item_ptr(eb, path->slots[0],
3303 struct btrfs_extent_item);
3304 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3305 bi = (struct btrfs_tree_block_info *)(ei + 1);
3306 level = btrfs_tree_block_level(eb, bi);
3307 } else {
3308 level = (int)extent_key->offset;
3309 }
3310 generation = btrfs_extent_generation(eb, ei);
3311 } else {
3312 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3313 u64 ref_owner;
3314 int ret;
3315
3316 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3317 ret = get_ref_objectid_v0(rc, path, extent_key,
3318 &ref_owner, NULL);
3319 if (ret < 0)
3320 return ret;
3321 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3322 level = (int)ref_owner;
3323 /* FIXME: get real generation */
3324 generation = 0;
3325 #else
3326 BUG();
3327 #endif
3328 }
3329
3330 btrfs_release_path(path);
3331
3332 BUG_ON(level == -1);
3333
3334 block = kmalloc(sizeof(*block), GFP_NOFS);
3335 if (!block)
3336 return -ENOMEM;
3337
3338 block->bytenr = extent_key->objectid;
3339 block->key.objectid = rc->extent_root->nodesize;
3340 block->key.offset = generation;
3341 block->level = level;
3342 block->key_ready = 0;
3343
3344 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3345 if (rb_node)
3346 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3347
3348 return 0;
3349 }
3350
3351 /*
3352 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3353 */
3354 static int __add_tree_block(struct reloc_control *rc,
3355 u64 bytenr, u32 blocksize,
3356 struct rb_root *blocks)
3357 {
3358 struct btrfs_path *path;
3359 struct btrfs_key key;
3360 int ret;
3361 bool skinny = btrfs_fs_incompat(rc->extent_root->fs_info,
3362 SKINNY_METADATA);
3363
3364 if (tree_block_processed(bytenr, rc))
3365 return 0;
3366
3367 if (tree_search(blocks, bytenr))
3368 return 0;
3369
3370 path = btrfs_alloc_path();
3371 if (!path)
3372 return -ENOMEM;
3373 again:
3374 key.objectid = bytenr;
3375 if (skinny) {
3376 key.type = BTRFS_METADATA_ITEM_KEY;
3377 key.offset = (u64)-1;
3378 } else {
3379 key.type = BTRFS_EXTENT_ITEM_KEY;
3380 key.offset = blocksize;
3381 }
3382
3383 path->search_commit_root = 1;
3384 path->skip_locking = 1;
3385 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3386 if (ret < 0)
3387 goto out;
3388
3389 if (ret > 0 && skinny) {
3390 if (path->slots[0]) {
3391 path->slots[0]--;
3392 btrfs_item_key_to_cpu(path->nodes[0], &key,
3393 path->slots[0]);
3394 if (key.objectid == bytenr &&
3395 (key.type == BTRFS_METADATA_ITEM_KEY ||
3396 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3397 key.offset == blocksize)))
3398 ret = 0;
3399 }
3400
3401 if (ret) {
3402 skinny = false;
3403 btrfs_release_path(path);
3404 goto again;
3405 }
3406 }
3407 BUG_ON(ret);
3408
3409 ret = add_tree_block(rc, &key, path, blocks);
3410 out:
3411 btrfs_free_path(path);
3412 return ret;
3413 }
3414
3415 /*
3416 * helper to check if the block use full backrefs for pointers in it
3417 */
3418 static int block_use_full_backref(struct reloc_control *rc,
3419 struct extent_buffer *eb)
3420 {
3421 u64 flags;
3422 int ret;
3423
3424 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3425 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3426 return 1;
3427
3428 ret = btrfs_lookup_extent_info(NULL, rc->extent_root,
3429 eb->start, btrfs_header_level(eb), 1,
3430 NULL, &flags);
3431 BUG_ON(ret);
3432
3433 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3434 ret = 1;
3435 else
3436 ret = 0;
3437 return ret;
3438 }
3439
3440 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3441 struct btrfs_block_group_cache *block_group,
3442 struct inode *inode,
3443 u64 ino)
3444 {
3445 struct btrfs_key key;
3446 struct btrfs_root *root = fs_info->tree_root;
3447 struct btrfs_trans_handle *trans;
3448 int ret = 0;
3449
3450 if (inode)
3451 goto truncate;
3452
3453 key.objectid = ino;
3454 key.type = BTRFS_INODE_ITEM_KEY;
3455 key.offset = 0;
3456
3457 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3458 if (IS_ERR(inode) || is_bad_inode(inode)) {
3459 if (!IS_ERR(inode))
3460 iput(inode);
3461 return -ENOENT;
3462 }
3463
3464 truncate:
3465 ret = btrfs_check_trunc_cache_free_space(root,
3466 &fs_info->global_block_rsv);
3467 if (ret)
3468 goto out;
3469
3470 trans = btrfs_join_transaction(root);
3471 if (IS_ERR(trans)) {
3472 ret = PTR_ERR(trans);
3473 goto out;
3474 }
3475
3476 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3477
3478 btrfs_end_transaction(trans, root);
3479 btrfs_btree_balance_dirty(root);
3480 out:
3481 iput(inode);
3482 return ret;
3483 }
3484
3485 /*
3486 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3487 * this function scans fs tree to find blocks reference the data extent
3488 */
3489 static int find_data_references(struct reloc_control *rc,
3490 struct btrfs_key *extent_key,
3491 struct extent_buffer *leaf,
3492 struct btrfs_extent_data_ref *ref,
3493 struct rb_root *blocks)
3494 {
3495 struct btrfs_path *path;
3496 struct tree_block *block;
3497 struct btrfs_root *root;
3498 struct btrfs_file_extent_item *fi;
3499 struct rb_node *rb_node;
3500 struct btrfs_key key;
3501 u64 ref_root;
3502 u64 ref_objectid;
3503 u64 ref_offset;
3504 u32 ref_count;
3505 u32 nritems;
3506 int err = 0;
3507 int added = 0;
3508 int counted;
3509 int ret;
3510
3511 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3512 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3513 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3514 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3515
3516 /*
3517 * This is an extent belonging to the free space cache, lets just delete
3518 * it and redo the search.
3519 */
3520 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3521 ret = delete_block_group_cache(rc->extent_root->fs_info,
3522 rc->block_group,
3523 NULL, ref_objectid);
3524 if (ret != -ENOENT)
3525 return ret;
3526 ret = 0;
3527 }
3528
3529 path = btrfs_alloc_path();
3530 if (!path)
3531 return -ENOMEM;
3532 path->reada = READA_FORWARD;
3533
3534 root = read_fs_root(rc->extent_root->fs_info, ref_root);
3535 if (IS_ERR(root)) {
3536 err = PTR_ERR(root);
3537 goto out;
3538 }
3539
3540 key.objectid = ref_objectid;
3541 key.type = BTRFS_EXTENT_DATA_KEY;
3542 if (ref_offset > ((u64)-1 << 32))
3543 key.offset = 0;
3544 else
3545 key.offset = ref_offset;
3546
3547 path->search_commit_root = 1;
3548 path->skip_locking = 1;
3549 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3550 if (ret < 0) {
3551 err = ret;
3552 goto out;
3553 }
3554
3555 leaf = path->nodes[0];
3556 nritems = btrfs_header_nritems(leaf);
3557 /*
3558 * the references in tree blocks that use full backrefs
3559 * are not counted in
3560 */
3561 if (block_use_full_backref(rc, leaf))
3562 counted = 0;
3563 else
3564 counted = 1;
3565 rb_node = tree_search(blocks, leaf->start);
3566 if (rb_node) {
3567 if (counted)
3568 added = 1;
3569 else
3570 path->slots[0] = nritems;
3571 }
3572
3573 while (ref_count > 0) {
3574 while (path->slots[0] >= nritems) {
3575 ret = btrfs_next_leaf(root, path);
3576 if (ret < 0) {
3577 err = ret;
3578 goto out;
3579 }
3580 if (WARN_ON(ret > 0))
3581 goto out;
3582
3583 leaf = path->nodes[0];
3584 nritems = btrfs_header_nritems(leaf);
3585 added = 0;
3586
3587 if (block_use_full_backref(rc, leaf))
3588 counted = 0;
3589 else
3590 counted = 1;
3591 rb_node = tree_search(blocks, leaf->start);
3592 if (rb_node) {
3593 if (counted)
3594 added = 1;
3595 else
3596 path->slots[0] = nritems;
3597 }
3598 }
3599
3600 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3601 if (WARN_ON(key.objectid != ref_objectid ||
3602 key.type != BTRFS_EXTENT_DATA_KEY))
3603 break;
3604
3605 fi = btrfs_item_ptr(leaf, path->slots[0],
3606 struct btrfs_file_extent_item);
3607
3608 if (btrfs_file_extent_type(leaf, fi) ==
3609 BTRFS_FILE_EXTENT_INLINE)
3610 goto next;
3611
3612 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3613 extent_key->objectid)
3614 goto next;
3615
3616 key.offset -= btrfs_file_extent_offset(leaf, fi);
3617 if (key.offset != ref_offset)
3618 goto next;
3619
3620 if (counted)
3621 ref_count--;
3622 if (added)
3623 goto next;
3624
3625 if (!tree_block_processed(leaf->start, rc)) {
3626 block = kmalloc(sizeof(*block), GFP_NOFS);
3627 if (!block) {
3628 err = -ENOMEM;
3629 break;
3630 }
3631 block->bytenr = leaf->start;
3632 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3633 block->level = 0;
3634 block->key_ready = 1;
3635 rb_node = tree_insert(blocks, block->bytenr,
3636 &block->rb_node);
3637 if (rb_node)
3638 backref_tree_panic(rb_node, -EEXIST,
3639 block->bytenr);
3640 }
3641 if (counted)
3642 added = 1;
3643 else
3644 path->slots[0] = nritems;
3645 next:
3646 path->slots[0]++;
3647
3648 }
3649 out:
3650 btrfs_free_path(path);
3651 return err;
3652 }
3653
3654 /*
3655 * helper to find all tree blocks that reference a given data extent
3656 */
3657 static noinline_for_stack
3658 int add_data_references(struct reloc_control *rc,
3659 struct btrfs_key *extent_key,
3660 struct btrfs_path *path,
3661 struct rb_root *blocks)
3662 {
3663 struct btrfs_key key;
3664 struct extent_buffer *eb;
3665 struct btrfs_extent_data_ref *dref;
3666 struct btrfs_extent_inline_ref *iref;
3667 unsigned long ptr;
3668 unsigned long end;
3669 u32 blocksize = rc->extent_root->nodesize;
3670 int ret = 0;
3671 int err = 0;
3672
3673 eb = path->nodes[0];
3674 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3675 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3676 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3677 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3678 ptr = end;
3679 else
3680 #endif
3681 ptr += sizeof(struct btrfs_extent_item);
3682
3683 while (ptr < end) {
3684 iref = (struct btrfs_extent_inline_ref *)ptr;
3685 key.type = btrfs_extent_inline_ref_type(eb, iref);
3686 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3687 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3688 ret = __add_tree_block(rc, key.offset, blocksize,
3689 blocks);
3690 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3691 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3692 ret = find_data_references(rc, extent_key,
3693 eb, dref, blocks);
3694 } else {
3695 BUG();
3696 }
3697 if (ret) {
3698 err = ret;
3699 goto out;
3700 }
3701 ptr += btrfs_extent_inline_ref_size(key.type);
3702 }
3703 WARN_ON(ptr > end);
3704
3705 while (1) {
3706 cond_resched();
3707 eb = path->nodes[0];
3708 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3709 ret = btrfs_next_leaf(rc->extent_root, path);
3710 if (ret < 0) {
3711 err = ret;
3712 break;
3713 }
3714 if (ret > 0)
3715 break;
3716 eb = path->nodes[0];
3717 }
3718
3719 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3720 if (key.objectid != extent_key->objectid)
3721 break;
3722
3723 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3724 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3725 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3726 #else
3727 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3728 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3729 #endif
3730 ret = __add_tree_block(rc, key.offset, blocksize,
3731 blocks);
3732 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3733 dref = btrfs_item_ptr(eb, path->slots[0],
3734 struct btrfs_extent_data_ref);
3735 ret = find_data_references(rc, extent_key,
3736 eb, dref, blocks);
3737 } else {
3738 ret = 0;
3739 }
3740 if (ret) {
3741 err = ret;
3742 break;
3743 }
3744 path->slots[0]++;
3745 }
3746 out:
3747 btrfs_release_path(path);
3748 if (err)
3749 free_block_list(blocks);
3750 return err;
3751 }
3752
3753 /*
3754 * helper to find next unprocessed extent
3755 */
3756 static noinline_for_stack
3757 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3758 struct btrfs_key *extent_key)
3759 {
3760 struct btrfs_key key;
3761 struct extent_buffer *leaf;
3762 u64 start, end, last;
3763 int ret;
3764
3765 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3766 while (1) {
3767 cond_resched();
3768 if (rc->search_start >= last) {
3769 ret = 1;
3770 break;
3771 }
3772
3773 key.objectid = rc->search_start;
3774 key.type = BTRFS_EXTENT_ITEM_KEY;
3775 key.offset = 0;
3776
3777 path->search_commit_root = 1;
3778 path->skip_locking = 1;
3779 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3780 0, 0);
3781 if (ret < 0)
3782 break;
3783 next:
3784 leaf = path->nodes[0];
3785 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3786 ret = btrfs_next_leaf(rc->extent_root, path);
3787 if (ret != 0)
3788 break;
3789 leaf = path->nodes[0];
3790 }
3791
3792 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3793 if (key.objectid >= last) {
3794 ret = 1;
3795 break;
3796 }
3797
3798 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3799 key.type != BTRFS_METADATA_ITEM_KEY) {
3800 path->slots[0]++;
3801 goto next;
3802 }
3803
3804 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3805 key.objectid + key.offset <= rc->search_start) {
3806 path->slots[0]++;
3807 goto next;
3808 }
3809
3810 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3811 key.objectid + rc->extent_root->nodesize <=
3812 rc->search_start) {
3813 path->slots[0]++;
3814 goto next;
3815 }
3816
3817 ret = find_first_extent_bit(&rc->processed_blocks,
3818 key.objectid, &start, &end,
3819 EXTENT_DIRTY, NULL);
3820
3821 if (ret == 0 && start <= key.objectid) {
3822 btrfs_release_path(path);
3823 rc->search_start = end + 1;
3824 } else {
3825 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3826 rc->search_start = key.objectid + key.offset;
3827 else
3828 rc->search_start = key.objectid +
3829 rc->extent_root->nodesize;
3830 memcpy(extent_key, &key, sizeof(key));
3831 return 0;
3832 }
3833 }
3834 btrfs_release_path(path);
3835 return ret;
3836 }
3837
3838 static void set_reloc_control(struct reloc_control *rc)
3839 {
3840 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3841
3842 mutex_lock(&fs_info->reloc_mutex);
3843 fs_info->reloc_ctl = rc;
3844 mutex_unlock(&fs_info->reloc_mutex);
3845 }
3846
3847 static void unset_reloc_control(struct reloc_control *rc)
3848 {
3849 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3850
3851 mutex_lock(&fs_info->reloc_mutex);
3852 fs_info->reloc_ctl = NULL;
3853 mutex_unlock(&fs_info->reloc_mutex);
3854 }
3855
3856 static int check_extent_flags(u64 flags)
3857 {
3858 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3859 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3860 return 1;
3861 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3862 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3863 return 1;
3864 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3865 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3866 return 1;
3867 return 0;
3868 }
3869
3870 static noinline_for_stack
3871 int prepare_to_relocate(struct reloc_control *rc)
3872 {
3873 struct btrfs_trans_handle *trans;
3874
3875 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root,
3876 BTRFS_BLOCK_RSV_TEMP);
3877 if (!rc->block_rsv)
3878 return -ENOMEM;
3879
3880 memset(&rc->cluster, 0, sizeof(rc->cluster));
3881 rc->search_start = rc->block_group->key.objectid;
3882 rc->extents_found = 0;
3883 rc->nodes_relocated = 0;
3884 rc->merging_rsv_size = 0;
3885 rc->reserved_bytes = 0;
3886 rc->block_rsv->size = rc->extent_root->nodesize *
3887 RELOCATION_RESERVED_NODES;
3888
3889 rc->create_reloc_tree = 1;
3890 set_reloc_control(rc);
3891
3892 trans = btrfs_join_transaction(rc->extent_root);
3893 if (IS_ERR(trans)) {
3894 unset_reloc_control(rc);
3895 /*
3896 * extent tree is not a ref_cow tree and has no reloc_root to
3897 * cleanup. And callers are responsible to free the above
3898 * block rsv.
3899 */
3900 return PTR_ERR(trans);
3901 }
3902 btrfs_commit_transaction(trans, rc->extent_root);
3903 return 0;
3904 }
3905
3906 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3907 {
3908 struct rb_root blocks = RB_ROOT;
3909 struct btrfs_key key;
3910 struct btrfs_trans_handle *trans = NULL;
3911 struct btrfs_path *path;
3912 struct btrfs_extent_item *ei;
3913 u64 flags;
3914 u32 item_size;
3915 int ret;
3916 int err = 0;
3917 int progress = 0;
3918
3919 path = btrfs_alloc_path();
3920 if (!path)
3921 return -ENOMEM;
3922 path->reada = READA_FORWARD;
3923
3924 ret = prepare_to_relocate(rc);
3925 if (ret) {
3926 err = ret;
3927 goto out_free;
3928 }
3929
3930 while (1) {
3931 rc->reserved_bytes = 0;
3932 ret = btrfs_block_rsv_refill(rc->extent_root,
3933 rc->block_rsv, rc->block_rsv->size,
3934 BTRFS_RESERVE_FLUSH_ALL);
3935 if (ret) {
3936 err = ret;
3937 break;
3938 }
3939 progress++;
3940 trans = btrfs_start_transaction(rc->extent_root, 0);
3941 if (IS_ERR(trans)) {
3942 err = PTR_ERR(trans);
3943 trans = NULL;
3944 break;
3945 }
3946 restart:
3947 if (update_backref_cache(trans, &rc->backref_cache)) {
3948 btrfs_end_transaction(trans, rc->extent_root);
3949 continue;
3950 }
3951
3952 ret = find_next_extent(rc, path, &key);
3953 if (ret < 0)
3954 err = ret;
3955 if (ret != 0)
3956 break;
3957
3958 rc->extents_found++;
3959
3960 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3961 struct btrfs_extent_item);
3962 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3963 if (item_size >= sizeof(*ei)) {
3964 flags = btrfs_extent_flags(path->nodes[0], ei);
3965 ret = check_extent_flags(flags);
3966 BUG_ON(ret);
3967
3968 } else {
3969 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3970 u64 ref_owner;
3971 int path_change = 0;
3972
3973 BUG_ON(item_size !=
3974 sizeof(struct btrfs_extent_item_v0));
3975 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
3976 &path_change);
3977 if (ret < 0) {
3978 err = ret;
3979 break;
3980 }
3981 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
3982 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
3983 else
3984 flags = BTRFS_EXTENT_FLAG_DATA;
3985
3986 if (path_change) {
3987 btrfs_release_path(path);
3988
3989 path->search_commit_root = 1;
3990 path->skip_locking = 1;
3991 ret = btrfs_search_slot(NULL, rc->extent_root,
3992 &key, path, 0, 0);
3993 if (ret < 0) {
3994 err = ret;
3995 break;
3996 }
3997 BUG_ON(ret > 0);
3998 }
3999 #else
4000 BUG();
4001 #endif
4002 }
4003
4004 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4005 ret = add_tree_block(rc, &key, path, &blocks);
4006 } else if (rc->stage == UPDATE_DATA_PTRS &&
4007 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4008 ret = add_data_references(rc, &key, path, &blocks);
4009 } else {
4010 btrfs_release_path(path);
4011 ret = 0;
4012 }
4013 if (ret < 0) {
4014 err = ret;
4015 break;
4016 }
4017
4018 if (!RB_EMPTY_ROOT(&blocks)) {
4019 ret = relocate_tree_blocks(trans, rc, &blocks);
4020 if (ret < 0) {
4021 /*
4022 * if we fail to relocate tree blocks, force to update
4023 * backref cache when committing transaction.
4024 */
4025 rc->backref_cache.last_trans = trans->transid - 1;
4026
4027 if (ret != -EAGAIN) {
4028 err = ret;
4029 break;
4030 }
4031 rc->extents_found--;
4032 rc->search_start = key.objectid;
4033 }
4034 }
4035
4036 btrfs_end_transaction_throttle(trans, rc->extent_root);
4037 btrfs_btree_balance_dirty(rc->extent_root);
4038 trans = NULL;
4039
4040 if (rc->stage == MOVE_DATA_EXTENTS &&
4041 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4042 rc->found_file_extent = 1;
4043 ret = relocate_data_extent(rc->data_inode,
4044 &key, &rc->cluster);
4045 if (ret < 0) {
4046 err = ret;
4047 break;
4048 }
4049 }
4050 }
4051 if (trans && progress && err == -ENOSPC) {
4052 ret = btrfs_force_chunk_alloc(trans, rc->extent_root,
4053 rc->block_group->flags);
4054 if (ret == 1) {
4055 err = 0;
4056 progress = 0;
4057 goto restart;
4058 }
4059 }
4060
4061 btrfs_release_path(path);
4062 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4063
4064 if (trans) {
4065 btrfs_end_transaction_throttle(trans, rc->extent_root);
4066 btrfs_btree_balance_dirty(rc->extent_root);
4067 }
4068
4069 if (!err) {
4070 ret = relocate_file_extent_cluster(rc->data_inode,
4071 &rc->cluster);
4072 if (ret < 0)
4073 err = ret;
4074 }
4075
4076 rc->create_reloc_tree = 0;
4077 set_reloc_control(rc);
4078
4079 backref_cache_cleanup(&rc->backref_cache);
4080 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4081
4082 err = prepare_to_merge(rc, err);
4083
4084 merge_reloc_roots(rc);
4085
4086 rc->merge_reloc_tree = 0;
4087 unset_reloc_control(rc);
4088 btrfs_block_rsv_release(rc->extent_root, rc->block_rsv, (u64)-1);
4089
4090 /* get rid of pinned extents */
4091 trans = btrfs_join_transaction(rc->extent_root);
4092 if (IS_ERR(trans))
4093 err = PTR_ERR(trans);
4094 else
4095 btrfs_commit_transaction(trans, rc->extent_root);
4096 out_free:
4097 btrfs_free_block_rsv(rc->extent_root, rc->block_rsv);
4098 btrfs_free_path(path);
4099 return err;
4100 }
4101
4102 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4103 struct btrfs_root *root, u64 objectid)
4104 {
4105 struct btrfs_path *path;
4106 struct btrfs_inode_item *item;
4107 struct extent_buffer *leaf;
4108 int ret;
4109
4110 path = btrfs_alloc_path();
4111 if (!path)
4112 return -ENOMEM;
4113
4114 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4115 if (ret)
4116 goto out;
4117
4118 leaf = path->nodes[0];
4119 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4120 memset_extent_buffer(leaf, 0, (unsigned long)item, sizeof(*item));
4121 btrfs_set_inode_generation(leaf, item, 1);
4122 btrfs_set_inode_size(leaf, item, 0);
4123 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4124 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4125 BTRFS_INODE_PREALLOC);
4126 btrfs_mark_buffer_dirty(leaf);
4127 out:
4128 btrfs_free_path(path);
4129 return ret;
4130 }
4131
4132 /*
4133 * helper to create inode for data relocation.
4134 * the inode is in data relocation tree and its link count is 0
4135 */
4136 static noinline_for_stack
4137 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4138 struct btrfs_block_group_cache *group)
4139 {
4140 struct inode *inode = NULL;
4141 struct btrfs_trans_handle *trans;
4142 struct btrfs_root *root;
4143 struct btrfs_key key;
4144 u64 objectid;
4145 int err = 0;
4146
4147 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4148 if (IS_ERR(root))
4149 return ERR_CAST(root);
4150
4151 trans = btrfs_start_transaction(root, 6);
4152 if (IS_ERR(trans))
4153 return ERR_CAST(trans);
4154
4155 err = btrfs_find_free_objectid(root, &objectid);
4156 if (err)
4157 goto out;
4158
4159 err = __insert_orphan_inode(trans, root, objectid);
4160 BUG_ON(err);
4161
4162 key.objectid = objectid;
4163 key.type = BTRFS_INODE_ITEM_KEY;
4164 key.offset = 0;
4165 inode = btrfs_iget(root->fs_info->sb, &key, root, NULL);
4166 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4167 BTRFS_I(inode)->index_cnt = group->key.objectid;
4168
4169 err = btrfs_orphan_add(trans, inode);
4170 out:
4171 btrfs_end_transaction(trans, root);
4172 btrfs_btree_balance_dirty(root);
4173 if (err) {
4174 if (inode)
4175 iput(inode);
4176 inode = ERR_PTR(err);
4177 }
4178 return inode;
4179 }
4180
4181 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4182 {
4183 struct reloc_control *rc;
4184
4185 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4186 if (!rc)
4187 return NULL;
4188
4189 INIT_LIST_HEAD(&rc->reloc_roots);
4190 backref_cache_init(&rc->backref_cache);
4191 mapping_tree_init(&rc->reloc_root_tree);
4192 extent_io_tree_init(&rc->processed_blocks,
4193 fs_info->btree_inode->i_mapping);
4194 return rc;
4195 }
4196
4197 /*
4198 * function to relocate all extents in a block group.
4199 */
4200 int btrfs_relocate_block_group(struct btrfs_root *extent_root, u64 group_start)
4201 {
4202 struct btrfs_fs_info *fs_info = extent_root->fs_info;
4203 struct reloc_control *rc;
4204 struct inode *inode;
4205 struct btrfs_path *path;
4206 int ret;
4207 int rw = 0;
4208 int err = 0;
4209
4210 rc = alloc_reloc_control(fs_info);
4211 if (!rc)
4212 return -ENOMEM;
4213
4214 rc->extent_root = extent_root;
4215
4216 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4217 BUG_ON(!rc->block_group);
4218
4219 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4220 if (ret) {
4221 err = ret;
4222 goto out;
4223 }
4224 rw = 1;
4225
4226 path = btrfs_alloc_path();
4227 if (!path) {
4228 err = -ENOMEM;
4229 goto out;
4230 }
4231
4232 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4233 path);
4234 btrfs_free_path(path);
4235
4236 if (!IS_ERR(inode))
4237 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4238 else
4239 ret = PTR_ERR(inode);
4240
4241 if (ret && ret != -ENOENT) {
4242 err = ret;
4243 goto out;
4244 }
4245
4246 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4247 if (IS_ERR(rc->data_inode)) {
4248 err = PTR_ERR(rc->data_inode);
4249 rc->data_inode = NULL;
4250 goto out;
4251 }
4252
4253 btrfs_info(extent_root->fs_info, "relocating block group %llu flags %llu",
4254 rc->block_group->key.objectid, rc->block_group->flags);
4255
4256 btrfs_wait_block_group_reservations(rc->block_group);
4257 btrfs_wait_nocow_writers(rc->block_group);
4258 btrfs_wait_ordered_roots(fs_info, -1,
4259 rc->block_group->key.objectid,
4260 rc->block_group->key.offset);
4261
4262 while (1) {
4263 mutex_lock(&fs_info->cleaner_mutex);
4264 ret = relocate_block_group(rc);
4265 mutex_unlock(&fs_info->cleaner_mutex);
4266 if (ret < 0) {
4267 err = ret;
4268 goto out;
4269 }
4270
4271 if (rc->extents_found == 0)
4272 break;
4273
4274 btrfs_info(extent_root->fs_info, "found %llu extents",
4275 rc->extents_found);
4276
4277 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4278 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4279 (u64)-1);
4280 if (ret) {
4281 err = ret;
4282 goto out;
4283 }
4284 invalidate_mapping_pages(rc->data_inode->i_mapping,
4285 0, -1);
4286 rc->stage = UPDATE_DATA_PTRS;
4287 }
4288 }
4289
4290 WARN_ON(rc->block_group->pinned > 0);
4291 WARN_ON(rc->block_group->reserved > 0);
4292 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4293 out:
4294 if (err && rw)
4295 btrfs_dec_block_group_ro(extent_root, rc->block_group);
4296 iput(rc->data_inode);
4297 btrfs_put_block_group(rc->block_group);
4298 kfree(rc);
4299 return err;
4300 }
4301
4302 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4303 {
4304 struct btrfs_trans_handle *trans;
4305 int ret, err;
4306
4307 trans = btrfs_start_transaction(root->fs_info->tree_root, 0);
4308 if (IS_ERR(trans))
4309 return PTR_ERR(trans);
4310
4311 memset(&root->root_item.drop_progress, 0,
4312 sizeof(root->root_item.drop_progress));
4313 root->root_item.drop_level = 0;
4314 btrfs_set_root_refs(&root->root_item, 0);
4315 ret = btrfs_update_root(trans, root->fs_info->tree_root,
4316 &root->root_key, &root->root_item);
4317
4318 err = btrfs_end_transaction(trans, root->fs_info->tree_root);
4319 if (err)
4320 return err;
4321 return ret;
4322 }
4323
4324 /*
4325 * recover relocation interrupted by system crash.
4326 *
4327 * this function resumes merging reloc trees with corresponding fs trees.
4328 * this is important for keeping the sharing of tree blocks
4329 */
4330 int btrfs_recover_relocation(struct btrfs_root *root)
4331 {
4332 LIST_HEAD(reloc_roots);
4333 struct btrfs_key key;
4334 struct btrfs_root *fs_root;
4335 struct btrfs_root *reloc_root;
4336 struct btrfs_path *path;
4337 struct extent_buffer *leaf;
4338 struct reloc_control *rc = NULL;
4339 struct btrfs_trans_handle *trans;
4340 int ret;
4341 int err = 0;
4342
4343 path = btrfs_alloc_path();
4344 if (!path)
4345 return -ENOMEM;
4346 path->reada = READA_BACK;
4347
4348 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4349 key.type = BTRFS_ROOT_ITEM_KEY;
4350 key.offset = (u64)-1;
4351
4352 while (1) {
4353 ret = btrfs_search_slot(NULL, root->fs_info->tree_root, &key,
4354 path, 0, 0);
4355 if (ret < 0) {
4356 err = ret;
4357 goto out;
4358 }
4359 if (ret > 0) {
4360 if (path->slots[0] == 0)
4361 break;
4362 path->slots[0]--;
4363 }
4364 leaf = path->nodes[0];
4365 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4366 btrfs_release_path(path);
4367
4368 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4369 key.type != BTRFS_ROOT_ITEM_KEY)
4370 break;
4371
4372 reloc_root = btrfs_read_fs_root(root, &key);
4373 if (IS_ERR(reloc_root)) {
4374 err = PTR_ERR(reloc_root);
4375 goto out;
4376 }
4377
4378 list_add(&reloc_root->root_list, &reloc_roots);
4379
4380 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4381 fs_root = read_fs_root(root->fs_info,
4382 reloc_root->root_key.offset);
4383 if (IS_ERR(fs_root)) {
4384 ret = PTR_ERR(fs_root);
4385 if (ret != -ENOENT) {
4386 err = ret;
4387 goto out;
4388 }
4389 ret = mark_garbage_root(reloc_root);
4390 if (ret < 0) {
4391 err = ret;
4392 goto out;
4393 }
4394 }
4395 }
4396
4397 if (key.offset == 0)
4398 break;
4399
4400 key.offset--;
4401 }
4402 btrfs_release_path(path);
4403
4404 if (list_empty(&reloc_roots))
4405 goto out;
4406
4407 rc = alloc_reloc_control(root->fs_info);
4408 if (!rc) {
4409 err = -ENOMEM;
4410 goto out;
4411 }
4412
4413 rc->extent_root = root->fs_info->extent_root;
4414
4415 set_reloc_control(rc);
4416
4417 trans = btrfs_join_transaction(rc->extent_root);
4418 if (IS_ERR(trans)) {
4419 unset_reloc_control(rc);
4420 err = PTR_ERR(trans);
4421 goto out_free;
4422 }
4423
4424 rc->merge_reloc_tree = 1;
4425
4426 while (!list_empty(&reloc_roots)) {
4427 reloc_root = list_entry(reloc_roots.next,
4428 struct btrfs_root, root_list);
4429 list_del(&reloc_root->root_list);
4430
4431 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4432 list_add_tail(&reloc_root->root_list,
4433 &rc->reloc_roots);
4434 continue;
4435 }
4436
4437 fs_root = read_fs_root(root->fs_info,
4438 reloc_root->root_key.offset);
4439 if (IS_ERR(fs_root)) {
4440 err = PTR_ERR(fs_root);
4441 goto out_free;
4442 }
4443
4444 err = __add_reloc_root(reloc_root);
4445 BUG_ON(err < 0); /* -ENOMEM or logic error */
4446 fs_root->reloc_root = reloc_root;
4447 }
4448
4449 err = btrfs_commit_transaction(trans, rc->extent_root);
4450 if (err)
4451 goto out_free;
4452
4453 merge_reloc_roots(rc);
4454
4455 unset_reloc_control(rc);
4456
4457 trans = btrfs_join_transaction(rc->extent_root);
4458 if (IS_ERR(trans))
4459 err = PTR_ERR(trans);
4460 else
4461 err = btrfs_commit_transaction(trans, rc->extent_root);
4462 out_free:
4463 kfree(rc);
4464 out:
4465 if (!list_empty(&reloc_roots))
4466 free_reloc_roots(&reloc_roots);
4467
4468 btrfs_free_path(path);
4469
4470 if (err == 0) {
4471 /* cleanup orphan inode in data relocation tree */
4472 fs_root = read_fs_root(root->fs_info,
4473 BTRFS_DATA_RELOC_TREE_OBJECTID);
4474 if (IS_ERR(fs_root))
4475 err = PTR_ERR(fs_root);
4476 else
4477 err = btrfs_orphan_cleanup(fs_root);
4478 }
4479 return err;
4480 }
4481
4482 /*
4483 * helper to add ordered checksum for data relocation.
4484 *
4485 * cloning checksum properly handles the nodatasum extents.
4486 * it also saves CPU time to re-calculate the checksum.
4487 */
4488 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4489 {
4490 struct btrfs_ordered_sum *sums;
4491 struct btrfs_ordered_extent *ordered;
4492 struct btrfs_root *root = BTRFS_I(inode)->root;
4493 int ret;
4494 u64 disk_bytenr;
4495 u64 new_bytenr;
4496 LIST_HEAD(list);
4497
4498 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4499 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4500
4501 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4502 ret = btrfs_lookup_csums_range(root->fs_info->csum_root, disk_bytenr,
4503 disk_bytenr + len - 1, &list, 0);
4504 if (ret)
4505 goto out;
4506
4507 while (!list_empty(&list)) {
4508 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4509 list_del_init(&sums->list);
4510
4511 /*
4512 * We need to offset the new_bytenr based on where the csum is.
4513 * We need to do this because we will read in entire prealloc
4514 * extents but we may have written to say the middle of the
4515 * prealloc extent, so we need to make sure the csum goes with
4516 * the right disk offset.
4517 *
4518 * We can do this because the data reloc inode refers strictly
4519 * to the on disk bytes, so we don't have to worry about
4520 * disk_len vs real len like with real inodes since it's all
4521 * disk length.
4522 */
4523 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4524 sums->bytenr = new_bytenr;
4525
4526 btrfs_add_ordered_sum(inode, ordered, sums);
4527 }
4528 out:
4529 btrfs_put_ordered_extent(ordered);
4530 return ret;
4531 }
4532
4533 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4534 struct btrfs_root *root, struct extent_buffer *buf,
4535 struct extent_buffer *cow)
4536 {
4537 struct reloc_control *rc;
4538 struct backref_node *node;
4539 int first_cow = 0;
4540 int level;
4541 int ret = 0;
4542
4543 rc = root->fs_info->reloc_ctl;
4544 if (!rc)
4545 return 0;
4546
4547 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4548 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4549
4550 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4551 if (buf == root->node)
4552 __update_reloc_root(root, cow->start);
4553 }
4554
4555 level = btrfs_header_level(buf);
4556 if (btrfs_header_generation(buf) <=
4557 btrfs_root_last_snapshot(&root->root_item))
4558 first_cow = 1;
4559
4560 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4561 rc->create_reloc_tree) {
4562 WARN_ON(!first_cow && level == 0);
4563
4564 node = rc->backref_cache.path[level];
4565 BUG_ON(node->bytenr != buf->start &&
4566 node->new_bytenr != buf->start);
4567
4568 drop_node_buffer(node);
4569 extent_buffer_get(cow);
4570 node->eb = cow;
4571 node->new_bytenr = cow->start;
4572
4573 if (!node->pending) {
4574 list_move_tail(&node->list,
4575 &rc->backref_cache.pending[level]);
4576 node->pending = 1;
4577 }
4578
4579 if (first_cow)
4580 __mark_block_processed(rc, node);
4581
4582 if (first_cow && level > 0)
4583 rc->nodes_relocated += buf->len;
4584 }
4585
4586 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4587 ret = replace_file_extents(trans, rc, root, cow);
4588 return ret;
4589 }
4590
4591 /*
4592 * called before creating snapshot. it calculates metadata reservation
4593 * required for relocating tree blocks in the snapshot
4594 */
4595 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4596 u64 *bytes_to_reserve)
4597 {
4598 struct btrfs_root *root;
4599 struct reloc_control *rc;
4600
4601 root = pending->root;
4602 if (!root->reloc_root)
4603 return;
4604
4605 rc = root->fs_info->reloc_ctl;
4606 if (!rc->merge_reloc_tree)
4607 return;
4608
4609 root = root->reloc_root;
4610 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4611 /*
4612 * relocation is in the stage of merging trees. the space
4613 * used by merging a reloc tree is twice the size of
4614 * relocated tree nodes in the worst case. half for cowing
4615 * the reloc tree, half for cowing the fs tree. the space
4616 * used by cowing the reloc tree will be freed after the
4617 * tree is dropped. if we create snapshot, cowing the fs
4618 * tree may use more space than it frees. so we need
4619 * reserve extra space.
4620 */
4621 *bytes_to_reserve += rc->nodes_relocated;
4622 }
4623
4624 /*
4625 * called after snapshot is created. migrate block reservation
4626 * and create reloc root for the newly created snapshot
4627 */
4628 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4629 struct btrfs_pending_snapshot *pending)
4630 {
4631 struct btrfs_root *root = pending->root;
4632 struct btrfs_root *reloc_root;
4633 struct btrfs_root *new_root;
4634 struct reloc_control *rc;
4635 int ret;
4636
4637 if (!root->reloc_root)
4638 return 0;
4639
4640 rc = root->fs_info->reloc_ctl;
4641 rc->merging_rsv_size += rc->nodes_relocated;
4642
4643 if (rc->merge_reloc_tree) {
4644 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4645 rc->block_rsv,
4646 rc->nodes_relocated);
4647 if (ret)
4648 return ret;
4649 }
4650
4651 new_root = pending->snap;
4652 reloc_root = create_reloc_root(trans, root->reloc_root,
4653 new_root->root_key.objectid);
4654 if (IS_ERR(reloc_root))
4655 return PTR_ERR(reloc_root);
4656
4657 ret = __add_reloc_root(reloc_root);
4658 BUG_ON(ret < 0);
4659 new_root->reloc_root = reloc_root;
4660
4661 if (rc->create_reloc_tree)
4662 ret = clone_backref_node(trans, rc, root, reloc_root);
4663 return ret;
4664 }
Linux with added FPC-III support