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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/hid
[mirror_ubuntu-artful-kernel.git] / fs / btrfs / relocation.c
1 /*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
25 #include "ctree.h"
26 #include "disk-io.h"
27 #include "transaction.h"
28 #include "volumes.h"
29 #include "locking.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
34 #include "qgroup.h"
35
36 /*
37 * backref_node, mapping_node and tree_block start with this
38 */
39 struct tree_entry {
40 struct rb_node rb_node;
41 u64 bytenr;
42 };
43
44 /*
45 * present a tree block in the backref cache
46 */
47 struct backref_node {
48 struct rb_node rb_node;
49 u64 bytenr;
50
51 u64 new_bytenr;
52 /* objectid of tree block owner, can be not uptodate */
53 u64 owner;
54 /* link to pending, changed or detached list */
55 struct list_head list;
56 /* list of upper level blocks reference this block */
57 struct list_head upper;
58 /* list of child blocks in the cache */
59 struct list_head lower;
60 /* NULL if this node is not tree root */
61 struct btrfs_root *root;
62 /* extent buffer got by COW the block */
63 struct extent_buffer *eb;
64 /* level of tree block */
65 unsigned int level:8;
66 /* is the block in non-reference counted tree */
67 unsigned int cowonly:1;
68 /* 1 if no child node in the cache */
69 unsigned int lowest:1;
70 /* is the extent buffer locked */
71 unsigned int locked:1;
72 /* has the block been processed */
73 unsigned int processed:1;
74 /* have backrefs of this block been checked */
75 unsigned int checked:1;
76 /*
77 * 1 if corresponding block has been cowed but some upper
78 * level block pointers may not point to the new location
79 */
80 unsigned int pending:1;
81 /*
82 * 1 if the backref node isn't connected to any other
83 * backref node.
84 */
85 unsigned int detached:1;
86 };
87
88 /*
89 * present a block pointer in the backref cache
90 */
91 struct backref_edge {
92 struct list_head list[2];
93 struct backref_node *node[2];
94 };
95
96 #define LOWER 0
97 #define UPPER 1
98 #define RELOCATION_RESERVED_NODES 256
99
100 struct backref_cache {
101 /* red black tree of all backref nodes in the cache */
102 struct rb_root rb_root;
103 /* for passing backref nodes to btrfs_reloc_cow_block */
104 struct backref_node *path[BTRFS_MAX_LEVEL];
105 /*
106 * list of blocks that have been cowed but some block
107 * pointers in upper level blocks may not reflect the
108 * new location
109 */
110 struct list_head pending[BTRFS_MAX_LEVEL];
111 /* list of backref nodes with no child node */
112 struct list_head leaves;
113 /* list of blocks that have been cowed in current transaction */
114 struct list_head changed;
115 /* list of detached backref node. */
116 struct list_head detached;
117
118 u64 last_trans;
119
120 int nr_nodes;
121 int nr_edges;
122 };
123
124 /*
125 * map address of tree root to tree
126 */
127 struct mapping_node {
128 struct rb_node rb_node;
129 u64 bytenr;
130 void *data;
131 };
132
133 struct mapping_tree {
134 struct rb_root rb_root;
135 spinlock_t lock;
136 };
137
138 /*
139 * present a tree block to process
140 */
141 struct tree_block {
142 struct rb_node rb_node;
143 u64 bytenr;
144 struct btrfs_key key;
145 unsigned int level:8;
146 unsigned int key_ready:1;
147 };
148
149 #define MAX_EXTENTS 128
150
151 struct file_extent_cluster {
152 u64 start;
153 u64 end;
154 u64 boundary[MAX_EXTENTS];
155 unsigned int nr;
156 };
157
158 struct reloc_control {
159 /* block group to relocate */
160 struct btrfs_block_group_cache *block_group;
161 /* extent tree */
162 struct btrfs_root *extent_root;
163 /* inode for moving data */
164 struct inode *data_inode;
165
166 struct btrfs_block_rsv *block_rsv;
167
168 struct backref_cache backref_cache;
169
170 struct file_extent_cluster cluster;
171 /* tree blocks have been processed */
172 struct extent_io_tree processed_blocks;
173 /* map start of tree root to corresponding reloc tree */
174 struct mapping_tree reloc_root_tree;
175 /* list of reloc trees */
176 struct list_head reloc_roots;
177 /* size of metadata reservation for merging reloc trees */
178 u64 merging_rsv_size;
179 /* size of relocated tree nodes */
180 u64 nodes_relocated;
181 /* reserved size for block group relocation*/
182 u64 reserved_bytes;
183
184 u64 search_start;
185 u64 extents_found;
186
187 unsigned int stage:8;
188 unsigned int create_reloc_tree:1;
189 unsigned int merge_reloc_tree:1;
190 unsigned int found_file_extent:1;
191 };
192
193 /* stages of data relocation */
194 #define MOVE_DATA_EXTENTS 0
195 #define UPDATE_DATA_PTRS 1
196
197 static void remove_backref_node(struct backref_cache *cache,
198 struct backref_node *node);
199 static void __mark_block_processed(struct reloc_control *rc,
200 struct backref_node *node);
201
202 static void mapping_tree_init(struct mapping_tree *tree)
203 {
204 tree->rb_root = RB_ROOT;
205 spin_lock_init(&tree->lock);
206 }
207
208 static void backref_cache_init(struct backref_cache *cache)
209 {
210 int i;
211 cache->rb_root = RB_ROOT;
212 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
213 INIT_LIST_HEAD(&cache->pending[i]);
214 INIT_LIST_HEAD(&cache->changed);
215 INIT_LIST_HEAD(&cache->detached);
216 INIT_LIST_HEAD(&cache->leaves);
217 }
218
219 static void backref_cache_cleanup(struct backref_cache *cache)
220 {
221 struct backref_node *node;
222 int i;
223
224 while (!list_empty(&cache->detached)) {
225 node = list_entry(cache->detached.next,
226 struct backref_node, list);
227 remove_backref_node(cache, node);
228 }
229
230 while (!list_empty(&cache->leaves)) {
231 node = list_entry(cache->leaves.next,
232 struct backref_node, lower);
233 remove_backref_node(cache, node);
234 }
235
236 cache->last_trans = 0;
237
238 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
239 ASSERT(list_empty(&cache->pending[i]));
240 ASSERT(list_empty(&cache->changed));
241 ASSERT(list_empty(&cache->detached));
242 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
243 ASSERT(!cache->nr_nodes);
244 ASSERT(!cache->nr_edges);
245 }
246
247 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
248 {
249 struct backref_node *node;
250
251 node = kzalloc(sizeof(*node), GFP_NOFS);
252 if (node) {
253 INIT_LIST_HEAD(&node->list);
254 INIT_LIST_HEAD(&node->upper);
255 INIT_LIST_HEAD(&node->lower);
256 RB_CLEAR_NODE(&node->rb_node);
257 cache->nr_nodes++;
258 }
259 return node;
260 }
261
262 static void free_backref_node(struct backref_cache *cache,
263 struct backref_node *node)
264 {
265 if (node) {
266 cache->nr_nodes--;
267 kfree(node);
268 }
269 }
270
271 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
272 {
273 struct backref_edge *edge;
274
275 edge = kzalloc(sizeof(*edge), GFP_NOFS);
276 if (edge)
277 cache->nr_edges++;
278 return edge;
279 }
280
281 static void free_backref_edge(struct backref_cache *cache,
282 struct backref_edge *edge)
283 {
284 if (edge) {
285 cache->nr_edges--;
286 kfree(edge);
287 }
288 }
289
290 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
291 struct rb_node *node)
292 {
293 struct rb_node **p = &root->rb_node;
294 struct rb_node *parent = NULL;
295 struct tree_entry *entry;
296
297 while (*p) {
298 parent = *p;
299 entry = rb_entry(parent, struct tree_entry, rb_node);
300
301 if (bytenr < entry->bytenr)
302 p = &(*p)->rb_left;
303 else if (bytenr > entry->bytenr)
304 p = &(*p)->rb_right;
305 else
306 return parent;
307 }
308
309 rb_link_node(node, parent, p);
310 rb_insert_color(node, root);
311 return NULL;
312 }
313
314 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
315 {
316 struct rb_node *n = root->rb_node;
317 struct tree_entry *entry;
318
319 while (n) {
320 entry = rb_entry(n, struct tree_entry, rb_node);
321
322 if (bytenr < entry->bytenr)
323 n = n->rb_left;
324 else if (bytenr > entry->bytenr)
325 n = n->rb_right;
326 else
327 return n;
328 }
329 return NULL;
330 }
331
332 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
333 {
334
335 struct btrfs_fs_info *fs_info = NULL;
336 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
337 rb_node);
338 if (bnode->root)
339 fs_info = bnode->root->fs_info;
340 btrfs_panic(fs_info, errno,
341 "Inconsistency in backref cache found at offset %llu",
342 bytenr);
343 }
344
345 /*
346 * walk up backref nodes until reach node presents tree root
347 */
348 static struct backref_node *walk_up_backref(struct backref_node *node,
349 struct backref_edge *edges[],
350 int *index)
351 {
352 struct backref_edge *edge;
353 int idx = *index;
354
355 while (!list_empty(&node->upper)) {
356 edge = list_entry(node->upper.next,
357 struct backref_edge, list[LOWER]);
358 edges[idx++] = edge;
359 node = edge->node[UPPER];
360 }
361 BUG_ON(node->detached);
362 *index = idx;
363 return node;
364 }
365
366 /*
367 * walk down backref nodes to find start of next reference path
368 */
369 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
370 int *index)
371 {
372 struct backref_edge *edge;
373 struct backref_node *lower;
374 int idx = *index;
375
376 while (idx > 0) {
377 edge = edges[idx - 1];
378 lower = edge->node[LOWER];
379 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
380 idx--;
381 continue;
382 }
383 edge = list_entry(edge->list[LOWER].next,
384 struct backref_edge, list[LOWER]);
385 edges[idx - 1] = edge;
386 *index = idx;
387 return edge->node[UPPER];
388 }
389 *index = 0;
390 return NULL;
391 }
392
393 static void unlock_node_buffer(struct backref_node *node)
394 {
395 if (node->locked) {
396 btrfs_tree_unlock(node->eb);
397 node->locked = 0;
398 }
399 }
400
401 static void drop_node_buffer(struct backref_node *node)
402 {
403 if (node->eb) {
404 unlock_node_buffer(node);
405 free_extent_buffer(node->eb);
406 node->eb = NULL;
407 }
408 }
409
410 static void drop_backref_node(struct backref_cache *tree,
411 struct backref_node *node)
412 {
413 BUG_ON(!list_empty(&node->upper));
414
415 drop_node_buffer(node);
416 list_del(&node->list);
417 list_del(&node->lower);
418 if (!RB_EMPTY_NODE(&node->rb_node))
419 rb_erase(&node->rb_node, &tree->rb_root);
420 free_backref_node(tree, node);
421 }
422
423 /*
424 * remove a backref node from the backref cache
425 */
426 static void remove_backref_node(struct backref_cache *cache,
427 struct backref_node *node)
428 {
429 struct backref_node *upper;
430 struct backref_edge *edge;
431
432 if (!node)
433 return;
434
435 BUG_ON(!node->lowest && !node->detached);
436 while (!list_empty(&node->upper)) {
437 edge = list_entry(node->upper.next, struct backref_edge,
438 list[LOWER]);
439 upper = edge->node[UPPER];
440 list_del(&edge->list[LOWER]);
441 list_del(&edge->list[UPPER]);
442 free_backref_edge(cache, edge);
443
444 if (RB_EMPTY_NODE(&upper->rb_node)) {
445 BUG_ON(!list_empty(&node->upper));
446 drop_backref_node(cache, node);
447 node = upper;
448 node->lowest = 1;
449 continue;
450 }
451 /*
452 * add the node to leaf node list if no other
453 * child block cached.
454 */
455 if (list_empty(&upper->lower)) {
456 list_add_tail(&upper->lower, &cache->leaves);
457 upper->lowest = 1;
458 }
459 }
460
461 drop_backref_node(cache, node);
462 }
463
464 static void update_backref_node(struct backref_cache *cache,
465 struct backref_node *node, u64 bytenr)
466 {
467 struct rb_node *rb_node;
468 rb_erase(&node->rb_node, &cache->rb_root);
469 node->bytenr = bytenr;
470 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
471 if (rb_node)
472 backref_tree_panic(rb_node, -EEXIST, bytenr);
473 }
474
475 /*
476 * update backref cache after a transaction commit
477 */
478 static int update_backref_cache(struct btrfs_trans_handle *trans,
479 struct backref_cache *cache)
480 {
481 struct backref_node *node;
482 int level = 0;
483
484 if (cache->last_trans == 0) {
485 cache->last_trans = trans->transid;
486 return 0;
487 }
488
489 if (cache->last_trans == trans->transid)
490 return 0;
491
492 /*
493 * detached nodes are used to avoid unnecessary backref
494 * lookup. transaction commit changes the extent tree.
495 * so the detached nodes are no longer useful.
496 */
497 while (!list_empty(&cache->detached)) {
498 node = list_entry(cache->detached.next,
499 struct backref_node, list);
500 remove_backref_node(cache, node);
501 }
502
503 while (!list_empty(&cache->changed)) {
504 node = list_entry(cache->changed.next,
505 struct backref_node, list);
506 list_del_init(&node->list);
507 BUG_ON(node->pending);
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510
511 /*
512 * some nodes can be left in the pending list if there were
513 * errors during processing the pending nodes.
514 */
515 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
516 list_for_each_entry(node, &cache->pending[level], list) {
517 BUG_ON(!node->pending);
518 if (node->bytenr == node->new_bytenr)
519 continue;
520 update_backref_node(cache, node, node->new_bytenr);
521 }
522 }
523
524 cache->last_trans = 0;
525 return 1;
526 }
527
528
529 static int should_ignore_root(struct btrfs_root *root)
530 {
531 struct btrfs_root *reloc_root;
532
533 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
534 return 0;
535
536 reloc_root = root->reloc_root;
537 if (!reloc_root)
538 return 0;
539
540 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
541 root->fs_info->running_transaction->transid - 1)
542 return 0;
543 /*
544 * if there is reloc tree and it was created in previous
545 * transaction backref lookup can find the reloc tree,
546 * so backref node for the fs tree root is useless for
547 * relocation.
548 */
549 return 1;
550 }
551 /*
552 * find reloc tree by address of tree root
553 */
554 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
555 u64 bytenr)
556 {
557 struct rb_node *rb_node;
558 struct mapping_node *node;
559 struct btrfs_root *root = NULL;
560
561 spin_lock(&rc->reloc_root_tree.lock);
562 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
563 if (rb_node) {
564 node = rb_entry(rb_node, struct mapping_node, rb_node);
565 root = (struct btrfs_root *)node->data;
566 }
567 spin_unlock(&rc->reloc_root_tree.lock);
568 return root;
569 }
570
571 static int is_cowonly_root(u64 root_objectid)
572 {
573 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
574 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
575 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
576 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
577 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
578 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
579 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
580 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
581 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
582 return 1;
583 return 0;
584 }
585
586 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
587 u64 root_objectid)
588 {
589 struct btrfs_key key;
590
591 key.objectid = root_objectid;
592 key.type = BTRFS_ROOT_ITEM_KEY;
593 if (is_cowonly_root(root_objectid))
594 key.offset = 0;
595 else
596 key.offset = (u64)-1;
597
598 return btrfs_get_fs_root(fs_info, &key, false);
599 }
600
601 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
602 static noinline_for_stack
603 struct btrfs_root *find_tree_root(struct reloc_control *rc,
604 struct extent_buffer *leaf,
605 struct btrfs_extent_ref_v0 *ref0)
606 {
607 struct btrfs_root *root;
608 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
609 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
610
611 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
612
613 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
614 BUG_ON(IS_ERR(root));
615
616 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
617 generation != btrfs_root_generation(&root->root_item))
618 return NULL;
619
620 return root;
621 }
622 #endif
623
624 static noinline_for_stack
625 int find_inline_backref(struct extent_buffer *leaf, int slot,
626 unsigned long *ptr, unsigned long *end)
627 {
628 struct btrfs_key key;
629 struct btrfs_extent_item *ei;
630 struct btrfs_tree_block_info *bi;
631 u32 item_size;
632
633 btrfs_item_key_to_cpu(leaf, &key, slot);
634
635 item_size = btrfs_item_size_nr(leaf, slot);
636 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
637 if (item_size < sizeof(*ei)) {
638 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
639 return 1;
640 }
641 #endif
642 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
643 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
644 BTRFS_EXTENT_FLAG_TREE_BLOCK));
645
646 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
647 item_size <= sizeof(*ei) + sizeof(*bi)) {
648 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
649 return 1;
650 }
651 if (key.type == BTRFS_METADATA_ITEM_KEY &&
652 item_size <= sizeof(*ei)) {
653 WARN_ON(item_size < sizeof(*ei));
654 return 1;
655 }
656
657 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
658 bi = (struct btrfs_tree_block_info *)(ei + 1);
659 *ptr = (unsigned long)(bi + 1);
660 } else {
661 *ptr = (unsigned long)(ei + 1);
662 }
663 *end = (unsigned long)ei + item_size;
664 return 0;
665 }
666
667 /*
668 * build backref tree for a given tree block. root of the backref tree
669 * corresponds the tree block, leaves of the backref tree correspond
670 * roots of b-trees that reference the tree block.
671 *
672 * the basic idea of this function is check backrefs of a given block
673 * to find upper level blocks that reference the block, and then check
674 * backrefs of these upper level blocks recursively. the recursion stop
675 * when tree root is reached or backrefs for the block is cached.
676 *
677 * NOTE: if we find backrefs for a block are cached, we know backrefs
678 * for all upper level blocks that directly/indirectly reference the
679 * block are also cached.
680 */
681 static noinline_for_stack
682 struct backref_node *build_backref_tree(struct reloc_control *rc,
683 struct btrfs_key *node_key,
684 int level, u64 bytenr)
685 {
686 struct backref_cache *cache = &rc->backref_cache;
687 struct btrfs_path *path1;
688 struct btrfs_path *path2;
689 struct extent_buffer *eb;
690 struct btrfs_root *root;
691 struct backref_node *cur;
692 struct backref_node *upper;
693 struct backref_node *lower;
694 struct backref_node *node = NULL;
695 struct backref_node *exist = NULL;
696 struct backref_edge *edge;
697 struct rb_node *rb_node;
698 struct btrfs_key key;
699 unsigned long end;
700 unsigned long ptr;
701 LIST_HEAD(list);
702 LIST_HEAD(useless);
703 int cowonly;
704 int ret;
705 int err = 0;
706 bool need_check = true;
707
708 path1 = btrfs_alloc_path();
709 path2 = btrfs_alloc_path();
710 if (!path1 || !path2) {
711 err = -ENOMEM;
712 goto out;
713 }
714 path1->reada = READA_FORWARD;
715 path2->reada = READA_FORWARD;
716
717 node = alloc_backref_node(cache);
718 if (!node) {
719 err = -ENOMEM;
720 goto out;
721 }
722
723 node->bytenr = bytenr;
724 node->level = level;
725 node->lowest = 1;
726 cur = node;
727 again:
728 end = 0;
729 ptr = 0;
730 key.objectid = cur->bytenr;
731 key.type = BTRFS_METADATA_ITEM_KEY;
732 key.offset = (u64)-1;
733
734 path1->search_commit_root = 1;
735 path1->skip_locking = 1;
736 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
737 0, 0);
738 if (ret < 0) {
739 err = ret;
740 goto out;
741 }
742 ASSERT(ret);
743 ASSERT(path1->slots[0]);
744
745 path1->slots[0]--;
746
747 WARN_ON(cur->checked);
748 if (!list_empty(&cur->upper)) {
749 /*
750 * the backref was added previously when processing
751 * backref of type BTRFS_TREE_BLOCK_REF_KEY
752 */
753 ASSERT(list_is_singular(&cur->upper));
754 edge = list_entry(cur->upper.next, struct backref_edge,
755 list[LOWER]);
756 ASSERT(list_empty(&edge->list[UPPER]));
757 exist = edge->node[UPPER];
758 /*
759 * add the upper level block to pending list if we need
760 * check its backrefs
761 */
762 if (!exist->checked)
763 list_add_tail(&edge->list[UPPER], &list);
764 } else {
765 exist = NULL;
766 }
767
768 while (1) {
769 cond_resched();
770 eb = path1->nodes[0];
771
772 if (ptr >= end) {
773 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
774 ret = btrfs_next_leaf(rc->extent_root, path1);
775 if (ret < 0) {
776 err = ret;
777 goto out;
778 }
779 if (ret > 0)
780 break;
781 eb = path1->nodes[0];
782 }
783
784 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
785 if (key.objectid != cur->bytenr) {
786 WARN_ON(exist);
787 break;
788 }
789
790 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
791 key.type == BTRFS_METADATA_ITEM_KEY) {
792 ret = find_inline_backref(eb, path1->slots[0],
793 &ptr, &end);
794 if (ret)
795 goto next;
796 }
797 }
798
799 if (ptr < end) {
800 /* update key for inline back ref */
801 struct btrfs_extent_inline_ref *iref;
802 iref = (struct btrfs_extent_inline_ref *)ptr;
803 key.type = btrfs_extent_inline_ref_type(eb, iref);
804 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
805 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
806 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
807 }
808
809 if (exist &&
810 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
811 exist->owner == key.offset) ||
812 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
813 exist->bytenr == key.offset))) {
814 exist = NULL;
815 goto next;
816 }
817
818 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
819 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
820 key.type == BTRFS_EXTENT_REF_V0_KEY) {
821 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
822 struct btrfs_extent_ref_v0 *ref0;
823 ref0 = btrfs_item_ptr(eb, path1->slots[0],
824 struct btrfs_extent_ref_v0);
825 if (key.objectid == key.offset) {
826 root = find_tree_root(rc, eb, ref0);
827 if (root && !should_ignore_root(root))
828 cur->root = root;
829 else
830 list_add(&cur->list, &useless);
831 break;
832 }
833 if (is_cowonly_root(btrfs_ref_root_v0(eb,
834 ref0)))
835 cur->cowonly = 1;
836 }
837 #else
838 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
839 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
840 #endif
841 if (key.objectid == key.offset) {
842 /*
843 * only root blocks of reloc trees use
844 * backref of this type.
845 */
846 root = find_reloc_root(rc, cur->bytenr);
847 ASSERT(root);
848 cur->root = root;
849 break;
850 }
851
852 edge = alloc_backref_edge(cache);
853 if (!edge) {
854 err = -ENOMEM;
855 goto out;
856 }
857 rb_node = tree_search(&cache->rb_root, key.offset);
858 if (!rb_node) {
859 upper = alloc_backref_node(cache);
860 if (!upper) {
861 free_backref_edge(cache, edge);
862 err = -ENOMEM;
863 goto out;
864 }
865 upper->bytenr = key.offset;
866 upper->level = cur->level + 1;
867 /*
868 * backrefs for the upper level block isn't
869 * cached, add the block to pending list
870 */
871 list_add_tail(&edge->list[UPPER], &list);
872 } else {
873 upper = rb_entry(rb_node, struct backref_node,
874 rb_node);
875 ASSERT(upper->checked);
876 INIT_LIST_HEAD(&edge->list[UPPER]);
877 }
878 list_add_tail(&edge->list[LOWER], &cur->upper);
879 edge->node[LOWER] = cur;
880 edge->node[UPPER] = upper;
881
882 goto next;
883 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
884 goto next;
885 }
886
887 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
888 root = read_fs_root(rc->extent_root->fs_info, key.offset);
889 if (IS_ERR(root)) {
890 err = PTR_ERR(root);
891 goto out;
892 }
893
894 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
895 cur->cowonly = 1;
896
897 if (btrfs_root_level(&root->root_item) == cur->level) {
898 /* tree root */
899 ASSERT(btrfs_root_bytenr(&root->root_item) ==
900 cur->bytenr);
901 if (should_ignore_root(root))
902 list_add(&cur->list, &useless);
903 else
904 cur->root = root;
905 break;
906 }
907
908 level = cur->level + 1;
909
910 /*
911 * searching the tree to find upper level blocks
912 * reference the block.
913 */
914 path2->search_commit_root = 1;
915 path2->skip_locking = 1;
916 path2->lowest_level = level;
917 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
918 path2->lowest_level = 0;
919 if (ret < 0) {
920 err = ret;
921 goto out;
922 }
923 if (ret > 0 && path2->slots[level] > 0)
924 path2->slots[level]--;
925
926 eb = path2->nodes[level];
927 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
928 cur->bytenr) {
929 btrfs_err(root->fs_info,
930 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
931 cur->bytenr, level - 1, root->objectid,
932 node_key->objectid, node_key->type,
933 node_key->offset);
934 err = -ENOENT;
935 goto out;
936 }
937 lower = cur;
938 need_check = true;
939 for (; level < BTRFS_MAX_LEVEL; level++) {
940 if (!path2->nodes[level]) {
941 ASSERT(btrfs_root_bytenr(&root->root_item) ==
942 lower->bytenr);
943 if (should_ignore_root(root))
944 list_add(&lower->list, &useless);
945 else
946 lower->root = root;
947 break;
948 }
949
950 edge = alloc_backref_edge(cache);
951 if (!edge) {
952 err = -ENOMEM;
953 goto out;
954 }
955
956 eb = path2->nodes[level];
957 rb_node = tree_search(&cache->rb_root, eb->start);
958 if (!rb_node) {
959 upper = alloc_backref_node(cache);
960 if (!upper) {
961 free_backref_edge(cache, edge);
962 err = -ENOMEM;
963 goto out;
964 }
965 upper->bytenr = eb->start;
966 upper->owner = btrfs_header_owner(eb);
967 upper->level = lower->level + 1;
968 if (!test_bit(BTRFS_ROOT_REF_COWS,
969 &root->state))
970 upper->cowonly = 1;
971
972 /*
973 * if we know the block isn't shared
974 * we can void checking its backrefs.
975 */
976 if (btrfs_block_can_be_shared(root, eb))
977 upper->checked = 0;
978 else
979 upper->checked = 1;
980
981 /*
982 * add the block to pending list if we
983 * need check its backrefs, we only do this once
984 * while walking up a tree as we will catch
985 * anything else later on.
986 */
987 if (!upper->checked && need_check) {
988 need_check = false;
989 list_add_tail(&edge->list[UPPER],
990 &list);
991 } else {
992 if (upper->checked)
993 need_check = true;
994 INIT_LIST_HEAD(&edge->list[UPPER]);
995 }
996 } else {
997 upper = rb_entry(rb_node, struct backref_node,
998 rb_node);
999 ASSERT(upper->checked);
1000 INIT_LIST_HEAD(&edge->list[UPPER]);
1001 if (!upper->owner)
1002 upper->owner = btrfs_header_owner(eb);
1003 }
1004 list_add_tail(&edge->list[LOWER], &lower->upper);
1005 edge->node[LOWER] = lower;
1006 edge->node[UPPER] = upper;
1007
1008 if (rb_node)
1009 break;
1010 lower = upper;
1011 upper = NULL;
1012 }
1013 btrfs_release_path(path2);
1014 next:
1015 if (ptr < end) {
1016 ptr += btrfs_extent_inline_ref_size(key.type);
1017 if (ptr >= end) {
1018 WARN_ON(ptr > end);
1019 ptr = 0;
1020 end = 0;
1021 }
1022 }
1023 if (ptr >= end)
1024 path1->slots[0]++;
1025 }
1026 btrfs_release_path(path1);
1027
1028 cur->checked = 1;
1029 WARN_ON(exist);
1030
1031 /* the pending list isn't empty, take the first block to process */
1032 if (!list_empty(&list)) {
1033 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1034 list_del_init(&edge->list[UPPER]);
1035 cur = edge->node[UPPER];
1036 goto again;
1037 }
1038
1039 /*
1040 * everything goes well, connect backref nodes and insert backref nodes
1041 * into the cache.
1042 */
1043 ASSERT(node->checked);
1044 cowonly = node->cowonly;
1045 if (!cowonly) {
1046 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1047 &node->rb_node);
1048 if (rb_node)
1049 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1050 list_add_tail(&node->lower, &cache->leaves);
1051 }
1052
1053 list_for_each_entry(edge, &node->upper, list[LOWER])
1054 list_add_tail(&edge->list[UPPER], &list);
1055
1056 while (!list_empty(&list)) {
1057 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1058 list_del_init(&edge->list[UPPER]);
1059 upper = edge->node[UPPER];
1060 if (upper->detached) {
1061 list_del(&edge->list[LOWER]);
1062 lower = edge->node[LOWER];
1063 free_backref_edge(cache, edge);
1064 if (list_empty(&lower->upper))
1065 list_add(&lower->list, &useless);
1066 continue;
1067 }
1068
1069 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1070 if (upper->lowest) {
1071 list_del_init(&upper->lower);
1072 upper->lowest = 0;
1073 }
1074
1075 list_add_tail(&edge->list[UPPER], &upper->lower);
1076 continue;
1077 }
1078
1079 if (!upper->checked) {
1080 /*
1081 * Still want to blow up for developers since this is a
1082 * logic bug.
1083 */
1084 ASSERT(0);
1085 err = -EINVAL;
1086 goto out;
1087 }
1088 if (cowonly != upper->cowonly) {
1089 ASSERT(0);
1090 err = -EINVAL;
1091 goto out;
1092 }
1093
1094 if (!cowonly) {
1095 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1096 &upper->rb_node);
1097 if (rb_node)
1098 backref_tree_panic(rb_node, -EEXIST,
1099 upper->bytenr);
1100 }
1101
1102 list_add_tail(&edge->list[UPPER], &upper->lower);
1103
1104 list_for_each_entry(edge, &upper->upper, list[LOWER])
1105 list_add_tail(&edge->list[UPPER], &list);
1106 }
1107 /*
1108 * process useless backref nodes. backref nodes for tree leaves
1109 * are deleted from the cache. backref nodes for upper level
1110 * tree blocks are left in the cache to avoid unnecessary backref
1111 * lookup.
1112 */
1113 while (!list_empty(&useless)) {
1114 upper = list_entry(useless.next, struct backref_node, list);
1115 list_del_init(&upper->list);
1116 ASSERT(list_empty(&upper->upper));
1117 if (upper == node)
1118 node = NULL;
1119 if (upper->lowest) {
1120 list_del_init(&upper->lower);
1121 upper->lowest = 0;
1122 }
1123 while (!list_empty(&upper->lower)) {
1124 edge = list_entry(upper->lower.next,
1125 struct backref_edge, list[UPPER]);
1126 list_del(&edge->list[UPPER]);
1127 list_del(&edge->list[LOWER]);
1128 lower = edge->node[LOWER];
1129 free_backref_edge(cache, edge);
1130
1131 if (list_empty(&lower->upper))
1132 list_add(&lower->list, &useless);
1133 }
1134 __mark_block_processed(rc, upper);
1135 if (upper->level > 0) {
1136 list_add(&upper->list, &cache->detached);
1137 upper->detached = 1;
1138 } else {
1139 rb_erase(&upper->rb_node, &cache->rb_root);
1140 free_backref_node(cache, upper);
1141 }
1142 }
1143 out:
1144 btrfs_free_path(path1);
1145 btrfs_free_path(path2);
1146 if (err) {
1147 while (!list_empty(&useless)) {
1148 lower = list_entry(useless.next,
1149 struct backref_node, list);
1150 list_del_init(&lower->list);
1151 }
1152 while (!list_empty(&list)) {
1153 edge = list_first_entry(&list, struct backref_edge,
1154 list[UPPER]);
1155 list_del(&edge->list[UPPER]);
1156 list_del(&edge->list[LOWER]);
1157 lower = edge->node[LOWER];
1158 upper = edge->node[UPPER];
1159 free_backref_edge(cache, edge);
1160
1161 /*
1162 * Lower is no longer linked to any upper backref nodes
1163 * and isn't in the cache, we can free it ourselves.
1164 */
1165 if (list_empty(&lower->upper) &&
1166 RB_EMPTY_NODE(&lower->rb_node))
1167 list_add(&lower->list, &useless);
1168
1169 if (!RB_EMPTY_NODE(&upper->rb_node))
1170 continue;
1171
1172 /* Add this guy's upper edges to the list to process */
1173 list_for_each_entry(edge, &upper->upper, list[LOWER])
1174 list_add_tail(&edge->list[UPPER], &list);
1175 if (list_empty(&upper->upper))
1176 list_add(&upper->list, &useless);
1177 }
1178
1179 while (!list_empty(&useless)) {
1180 lower = list_entry(useless.next,
1181 struct backref_node, list);
1182 list_del_init(&lower->list);
1183 if (lower == node)
1184 node = NULL;
1185 free_backref_node(cache, lower);
1186 }
1187
1188 free_backref_node(cache, node);
1189 return ERR_PTR(err);
1190 }
1191 ASSERT(!node || !node->detached);
1192 return node;
1193 }
1194
1195 /*
1196 * helper to add backref node for the newly created snapshot.
1197 * the backref node is created by cloning backref node that
1198 * corresponds to root of source tree
1199 */
1200 static int clone_backref_node(struct btrfs_trans_handle *trans,
1201 struct reloc_control *rc,
1202 struct btrfs_root *src,
1203 struct btrfs_root *dest)
1204 {
1205 struct btrfs_root *reloc_root = src->reloc_root;
1206 struct backref_cache *cache = &rc->backref_cache;
1207 struct backref_node *node = NULL;
1208 struct backref_node *new_node;
1209 struct backref_edge *edge;
1210 struct backref_edge *new_edge;
1211 struct rb_node *rb_node;
1212
1213 if (cache->last_trans > 0)
1214 update_backref_cache(trans, cache);
1215
1216 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1217 if (rb_node) {
1218 node = rb_entry(rb_node, struct backref_node, rb_node);
1219 if (node->detached)
1220 node = NULL;
1221 else
1222 BUG_ON(node->new_bytenr != reloc_root->node->start);
1223 }
1224
1225 if (!node) {
1226 rb_node = tree_search(&cache->rb_root,
1227 reloc_root->commit_root->start);
1228 if (rb_node) {
1229 node = rb_entry(rb_node, struct backref_node,
1230 rb_node);
1231 BUG_ON(node->detached);
1232 }
1233 }
1234
1235 if (!node)
1236 return 0;
1237
1238 new_node = alloc_backref_node(cache);
1239 if (!new_node)
1240 return -ENOMEM;
1241
1242 new_node->bytenr = dest->node->start;
1243 new_node->level = node->level;
1244 new_node->lowest = node->lowest;
1245 new_node->checked = 1;
1246 new_node->root = dest;
1247
1248 if (!node->lowest) {
1249 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1250 new_edge = alloc_backref_edge(cache);
1251 if (!new_edge)
1252 goto fail;
1253
1254 new_edge->node[UPPER] = new_node;
1255 new_edge->node[LOWER] = edge->node[LOWER];
1256 list_add_tail(&new_edge->list[UPPER],
1257 &new_node->lower);
1258 }
1259 } else {
1260 list_add_tail(&new_node->lower, &cache->leaves);
1261 }
1262
1263 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1264 &new_node->rb_node);
1265 if (rb_node)
1266 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1267
1268 if (!new_node->lowest) {
1269 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1270 list_add_tail(&new_edge->list[LOWER],
1271 &new_edge->node[LOWER]->upper);
1272 }
1273 }
1274 return 0;
1275 fail:
1276 while (!list_empty(&new_node->lower)) {
1277 new_edge = list_entry(new_node->lower.next,
1278 struct backref_edge, list[UPPER]);
1279 list_del(&new_edge->list[UPPER]);
1280 free_backref_edge(cache, new_edge);
1281 }
1282 free_backref_node(cache, new_node);
1283 return -ENOMEM;
1284 }
1285
1286 /*
1287 * helper to add 'address of tree root -> reloc tree' mapping
1288 */
1289 static int __must_check __add_reloc_root(struct btrfs_root *root)
1290 {
1291 struct btrfs_fs_info *fs_info = root->fs_info;
1292 struct rb_node *rb_node;
1293 struct mapping_node *node;
1294 struct reloc_control *rc = fs_info->reloc_ctl;
1295
1296 node = kmalloc(sizeof(*node), GFP_NOFS);
1297 if (!node)
1298 return -ENOMEM;
1299
1300 node->bytenr = root->node->start;
1301 node->data = root;
1302
1303 spin_lock(&rc->reloc_root_tree.lock);
1304 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1305 node->bytenr, &node->rb_node);
1306 spin_unlock(&rc->reloc_root_tree.lock);
1307 if (rb_node) {
1308 btrfs_panic(fs_info, -EEXIST,
1309 "Duplicate root found for start=%llu while inserting into relocation tree",
1310 node->bytenr);
1311 kfree(node);
1312 return -EEXIST;
1313 }
1314
1315 list_add_tail(&root->root_list, &rc->reloc_roots);
1316 return 0;
1317 }
1318
1319 /*
1320 * helper to delete the 'address of tree root -> reloc tree'
1321 * mapping
1322 */
1323 static void __del_reloc_root(struct btrfs_root *root)
1324 {
1325 struct btrfs_fs_info *fs_info = root->fs_info;
1326 struct rb_node *rb_node;
1327 struct mapping_node *node = NULL;
1328 struct reloc_control *rc = fs_info->reloc_ctl;
1329
1330 spin_lock(&rc->reloc_root_tree.lock);
1331 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1332 root->node->start);
1333 if (rb_node) {
1334 node = rb_entry(rb_node, struct mapping_node, rb_node);
1335 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1336 }
1337 spin_unlock(&rc->reloc_root_tree.lock);
1338
1339 if (!node)
1340 return;
1341 BUG_ON((struct btrfs_root *)node->data != root);
1342
1343 spin_lock(&fs_info->trans_lock);
1344 list_del_init(&root->root_list);
1345 spin_unlock(&fs_info->trans_lock);
1346 kfree(node);
1347 }
1348
1349 /*
1350 * helper to update the 'address of tree root -> reloc tree'
1351 * mapping
1352 */
1353 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1354 {
1355 struct btrfs_fs_info *fs_info = root->fs_info;
1356 struct rb_node *rb_node;
1357 struct mapping_node *node = NULL;
1358 struct reloc_control *rc = fs_info->reloc_ctl;
1359
1360 spin_lock(&rc->reloc_root_tree.lock);
1361 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1362 root->node->start);
1363 if (rb_node) {
1364 node = rb_entry(rb_node, struct mapping_node, rb_node);
1365 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1366 }
1367 spin_unlock(&rc->reloc_root_tree.lock);
1368
1369 if (!node)
1370 return 0;
1371 BUG_ON((struct btrfs_root *)node->data != root);
1372
1373 spin_lock(&rc->reloc_root_tree.lock);
1374 node->bytenr = new_bytenr;
1375 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1376 node->bytenr, &node->rb_node);
1377 spin_unlock(&rc->reloc_root_tree.lock);
1378 if (rb_node)
1379 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1380 return 0;
1381 }
1382
1383 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1384 struct btrfs_root *root, u64 objectid)
1385 {
1386 struct btrfs_fs_info *fs_info = root->fs_info;
1387 struct btrfs_root *reloc_root;
1388 struct extent_buffer *eb;
1389 struct btrfs_root_item *root_item;
1390 struct btrfs_key root_key;
1391 int ret;
1392
1393 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1394 BUG_ON(!root_item);
1395
1396 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1397 root_key.type = BTRFS_ROOT_ITEM_KEY;
1398 root_key.offset = objectid;
1399
1400 if (root->root_key.objectid == objectid) {
1401 u64 commit_root_gen;
1402
1403 /* called by btrfs_init_reloc_root */
1404 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1405 BTRFS_TREE_RELOC_OBJECTID);
1406 BUG_ON(ret);
1407 /*
1408 * Set the last_snapshot field to the generation of the commit
1409 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1410 * correctly (returns true) when the relocation root is created
1411 * either inside the critical section of a transaction commit
1412 * (through transaction.c:qgroup_account_snapshot()) and when
1413 * it's created before the transaction commit is started.
1414 */
1415 commit_root_gen = btrfs_header_generation(root->commit_root);
1416 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1417 } else {
1418 /*
1419 * called by btrfs_reloc_post_snapshot_hook.
1420 * the source tree is a reloc tree, all tree blocks
1421 * modified after it was created have RELOC flag
1422 * set in their headers. so it's OK to not update
1423 * the 'last_snapshot'.
1424 */
1425 ret = btrfs_copy_root(trans, root, root->node, &eb,
1426 BTRFS_TREE_RELOC_OBJECTID);
1427 BUG_ON(ret);
1428 }
1429
1430 memcpy(root_item, &root->root_item, sizeof(*root_item));
1431 btrfs_set_root_bytenr(root_item, eb->start);
1432 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1433 btrfs_set_root_generation(root_item, trans->transid);
1434
1435 if (root->root_key.objectid == objectid) {
1436 btrfs_set_root_refs(root_item, 0);
1437 memset(&root_item->drop_progress, 0,
1438 sizeof(struct btrfs_disk_key));
1439 root_item->drop_level = 0;
1440 }
1441
1442 btrfs_tree_unlock(eb);
1443 free_extent_buffer(eb);
1444
1445 ret = btrfs_insert_root(trans, fs_info->tree_root,
1446 &root_key, root_item);
1447 BUG_ON(ret);
1448 kfree(root_item);
1449
1450 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1451 BUG_ON(IS_ERR(reloc_root));
1452 reloc_root->last_trans = trans->transid;
1453 return reloc_root;
1454 }
1455
1456 /*
1457 * create reloc tree for a given fs tree. reloc tree is just a
1458 * snapshot of the fs tree with special root objectid.
1459 */
1460 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1461 struct btrfs_root *root)
1462 {
1463 struct btrfs_fs_info *fs_info = root->fs_info;
1464 struct btrfs_root *reloc_root;
1465 struct reloc_control *rc = fs_info->reloc_ctl;
1466 struct btrfs_block_rsv *rsv;
1467 int clear_rsv = 0;
1468 int ret;
1469
1470 if (root->reloc_root) {
1471 reloc_root = root->reloc_root;
1472 reloc_root->last_trans = trans->transid;
1473 return 0;
1474 }
1475
1476 if (!rc || !rc->create_reloc_tree ||
1477 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1478 return 0;
1479
1480 if (!trans->reloc_reserved) {
1481 rsv = trans->block_rsv;
1482 trans->block_rsv = rc->block_rsv;
1483 clear_rsv = 1;
1484 }
1485 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1486 if (clear_rsv)
1487 trans->block_rsv = rsv;
1488
1489 ret = __add_reloc_root(reloc_root);
1490 BUG_ON(ret < 0);
1491 root->reloc_root = reloc_root;
1492 return 0;
1493 }
1494
1495 /*
1496 * update root item of reloc tree
1497 */
1498 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1499 struct btrfs_root *root)
1500 {
1501 struct btrfs_fs_info *fs_info = root->fs_info;
1502 struct btrfs_root *reloc_root;
1503 struct btrfs_root_item *root_item;
1504 int ret;
1505
1506 if (!root->reloc_root)
1507 goto out;
1508
1509 reloc_root = root->reloc_root;
1510 root_item = &reloc_root->root_item;
1511
1512 if (fs_info->reloc_ctl->merge_reloc_tree &&
1513 btrfs_root_refs(root_item) == 0) {
1514 root->reloc_root = NULL;
1515 __del_reloc_root(reloc_root);
1516 }
1517
1518 if (reloc_root->commit_root != reloc_root->node) {
1519 btrfs_set_root_node(root_item, reloc_root->node);
1520 free_extent_buffer(reloc_root->commit_root);
1521 reloc_root->commit_root = btrfs_root_node(reloc_root);
1522 }
1523
1524 ret = btrfs_update_root(trans, fs_info->tree_root,
1525 &reloc_root->root_key, root_item);
1526 BUG_ON(ret);
1527
1528 out:
1529 return 0;
1530 }
1531
1532 /*
1533 * helper to find first cached inode with inode number >= objectid
1534 * in a subvolume
1535 */
1536 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1537 {
1538 struct rb_node *node;
1539 struct rb_node *prev;
1540 struct btrfs_inode *entry;
1541 struct inode *inode;
1542
1543 spin_lock(&root->inode_lock);
1544 again:
1545 node = root->inode_tree.rb_node;
1546 prev = NULL;
1547 while (node) {
1548 prev = node;
1549 entry = rb_entry(node, struct btrfs_inode, rb_node);
1550
1551 if (objectid < btrfs_ino(entry))
1552 node = node->rb_left;
1553 else if (objectid > btrfs_ino(entry))
1554 node = node->rb_right;
1555 else
1556 break;
1557 }
1558 if (!node) {
1559 while (prev) {
1560 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1561 if (objectid <= btrfs_ino(entry)) {
1562 node = prev;
1563 break;
1564 }
1565 prev = rb_next(prev);
1566 }
1567 }
1568 while (node) {
1569 entry = rb_entry(node, struct btrfs_inode, rb_node);
1570 inode = igrab(&entry->vfs_inode);
1571 if (inode) {
1572 spin_unlock(&root->inode_lock);
1573 return inode;
1574 }
1575
1576 objectid = btrfs_ino(entry) + 1;
1577 if (cond_resched_lock(&root->inode_lock))
1578 goto again;
1579
1580 node = rb_next(node);
1581 }
1582 spin_unlock(&root->inode_lock);
1583 return NULL;
1584 }
1585
1586 static int in_block_group(u64 bytenr,
1587 struct btrfs_block_group_cache *block_group)
1588 {
1589 if (bytenr >= block_group->key.objectid &&
1590 bytenr < block_group->key.objectid + block_group->key.offset)
1591 return 1;
1592 return 0;
1593 }
1594
1595 /*
1596 * get new location of data
1597 */
1598 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1599 u64 bytenr, u64 num_bytes)
1600 {
1601 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1602 struct btrfs_path *path;
1603 struct btrfs_file_extent_item *fi;
1604 struct extent_buffer *leaf;
1605 int ret;
1606
1607 path = btrfs_alloc_path();
1608 if (!path)
1609 return -ENOMEM;
1610
1611 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1612 ret = btrfs_lookup_file_extent(NULL, root, path,
1613 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1614 if (ret < 0)
1615 goto out;
1616 if (ret > 0) {
1617 ret = -ENOENT;
1618 goto out;
1619 }
1620
1621 leaf = path->nodes[0];
1622 fi = btrfs_item_ptr(leaf, path->slots[0],
1623 struct btrfs_file_extent_item);
1624
1625 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1626 btrfs_file_extent_compression(leaf, fi) ||
1627 btrfs_file_extent_encryption(leaf, fi) ||
1628 btrfs_file_extent_other_encoding(leaf, fi));
1629
1630 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1631 ret = -EINVAL;
1632 goto out;
1633 }
1634
1635 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1636 ret = 0;
1637 out:
1638 btrfs_free_path(path);
1639 return ret;
1640 }
1641
1642 /*
1643 * update file extent items in the tree leaf to point to
1644 * the new locations.
1645 */
1646 static noinline_for_stack
1647 int replace_file_extents(struct btrfs_trans_handle *trans,
1648 struct reloc_control *rc,
1649 struct btrfs_root *root,
1650 struct extent_buffer *leaf)
1651 {
1652 struct btrfs_fs_info *fs_info = root->fs_info;
1653 struct btrfs_key key;
1654 struct btrfs_file_extent_item *fi;
1655 struct inode *inode = NULL;
1656 u64 parent;
1657 u64 bytenr;
1658 u64 new_bytenr = 0;
1659 u64 num_bytes;
1660 u64 end;
1661 u32 nritems;
1662 u32 i;
1663 int ret = 0;
1664 int first = 1;
1665 int dirty = 0;
1666
1667 if (rc->stage != UPDATE_DATA_PTRS)
1668 return 0;
1669
1670 /* reloc trees always use full backref */
1671 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1672 parent = leaf->start;
1673 else
1674 parent = 0;
1675
1676 nritems = btrfs_header_nritems(leaf);
1677 for (i = 0; i < nritems; i++) {
1678 cond_resched();
1679 btrfs_item_key_to_cpu(leaf, &key, i);
1680 if (key.type != BTRFS_EXTENT_DATA_KEY)
1681 continue;
1682 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1683 if (btrfs_file_extent_type(leaf, fi) ==
1684 BTRFS_FILE_EXTENT_INLINE)
1685 continue;
1686 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1687 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1688 if (bytenr == 0)
1689 continue;
1690 if (!in_block_group(bytenr, rc->block_group))
1691 continue;
1692
1693 /*
1694 * if we are modifying block in fs tree, wait for readpage
1695 * to complete and drop the extent cache
1696 */
1697 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1698 if (first) {
1699 inode = find_next_inode(root, key.objectid);
1700 first = 0;
1701 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1702 btrfs_add_delayed_iput(inode);
1703 inode = find_next_inode(root, key.objectid);
1704 }
1705 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1706 end = key.offset +
1707 btrfs_file_extent_num_bytes(leaf, fi);
1708 WARN_ON(!IS_ALIGNED(key.offset,
1709 fs_info->sectorsize));
1710 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1711 end--;
1712 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1713 key.offset, end);
1714 if (!ret)
1715 continue;
1716
1717 btrfs_drop_extent_cache(BTRFS_I(inode),
1718 key.offset, end, 1);
1719 unlock_extent(&BTRFS_I(inode)->io_tree,
1720 key.offset, end);
1721 }
1722 }
1723
1724 ret = get_new_location(rc->data_inode, &new_bytenr,
1725 bytenr, num_bytes);
1726 if (ret) {
1727 /*
1728 * Don't have to abort since we've not changed anything
1729 * in the file extent yet.
1730 */
1731 break;
1732 }
1733
1734 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1735 dirty = 1;
1736
1737 key.offset -= btrfs_file_extent_offset(leaf, fi);
1738 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1739 num_bytes, parent,
1740 btrfs_header_owner(leaf),
1741 key.objectid, key.offset);
1742 if (ret) {
1743 btrfs_abort_transaction(trans, ret);
1744 break;
1745 }
1746
1747 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1748 parent, btrfs_header_owner(leaf),
1749 key.objectid, key.offset);
1750 if (ret) {
1751 btrfs_abort_transaction(trans, ret);
1752 break;
1753 }
1754 }
1755 if (dirty)
1756 btrfs_mark_buffer_dirty(leaf);
1757 if (inode)
1758 btrfs_add_delayed_iput(inode);
1759 return ret;
1760 }
1761
1762 static noinline_for_stack
1763 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1764 struct btrfs_path *path, int level)
1765 {
1766 struct btrfs_disk_key key1;
1767 struct btrfs_disk_key key2;
1768 btrfs_node_key(eb, &key1, slot);
1769 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1770 return memcmp(&key1, &key2, sizeof(key1));
1771 }
1772
1773 /*
1774 * try to replace tree blocks in fs tree with the new blocks
1775 * in reloc tree. tree blocks haven't been modified since the
1776 * reloc tree was create can be replaced.
1777 *
1778 * if a block was replaced, level of the block + 1 is returned.
1779 * if no block got replaced, 0 is returned. if there are other
1780 * errors, a negative error number is returned.
1781 */
1782 static noinline_for_stack
1783 int replace_path(struct btrfs_trans_handle *trans,
1784 struct btrfs_root *dest, struct btrfs_root *src,
1785 struct btrfs_path *path, struct btrfs_key *next_key,
1786 int lowest_level, int max_level)
1787 {
1788 struct btrfs_fs_info *fs_info = dest->fs_info;
1789 struct extent_buffer *eb;
1790 struct extent_buffer *parent;
1791 struct btrfs_key key;
1792 u64 old_bytenr;
1793 u64 new_bytenr;
1794 u64 old_ptr_gen;
1795 u64 new_ptr_gen;
1796 u64 last_snapshot;
1797 u32 blocksize;
1798 int cow = 0;
1799 int level;
1800 int ret;
1801 int slot;
1802
1803 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1804 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1805
1806 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1807 again:
1808 slot = path->slots[lowest_level];
1809 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1810
1811 eb = btrfs_lock_root_node(dest);
1812 btrfs_set_lock_blocking(eb);
1813 level = btrfs_header_level(eb);
1814
1815 if (level < lowest_level) {
1816 btrfs_tree_unlock(eb);
1817 free_extent_buffer(eb);
1818 return 0;
1819 }
1820
1821 if (cow) {
1822 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1823 BUG_ON(ret);
1824 }
1825 btrfs_set_lock_blocking(eb);
1826
1827 if (next_key) {
1828 next_key->objectid = (u64)-1;
1829 next_key->type = (u8)-1;
1830 next_key->offset = (u64)-1;
1831 }
1832
1833 parent = eb;
1834 while (1) {
1835 level = btrfs_header_level(parent);
1836 BUG_ON(level < lowest_level);
1837
1838 ret = btrfs_bin_search(parent, &key, level, &slot);
1839 if (ret && slot > 0)
1840 slot--;
1841
1842 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1843 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1844
1845 old_bytenr = btrfs_node_blockptr(parent, slot);
1846 blocksize = fs_info->nodesize;
1847 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1848
1849 if (level <= max_level) {
1850 eb = path->nodes[level];
1851 new_bytenr = btrfs_node_blockptr(eb,
1852 path->slots[level]);
1853 new_ptr_gen = btrfs_node_ptr_generation(eb,
1854 path->slots[level]);
1855 } else {
1856 new_bytenr = 0;
1857 new_ptr_gen = 0;
1858 }
1859
1860 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1861 ret = level;
1862 break;
1863 }
1864
1865 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1866 memcmp_node_keys(parent, slot, path, level)) {
1867 if (level <= lowest_level) {
1868 ret = 0;
1869 break;
1870 }
1871
1872 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen);
1873 if (IS_ERR(eb)) {
1874 ret = PTR_ERR(eb);
1875 break;
1876 } else if (!extent_buffer_uptodate(eb)) {
1877 ret = -EIO;
1878 free_extent_buffer(eb);
1879 break;
1880 }
1881 btrfs_tree_lock(eb);
1882 if (cow) {
1883 ret = btrfs_cow_block(trans, dest, eb, parent,
1884 slot, &eb);
1885 BUG_ON(ret);
1886 }
1887 btrfs_set_lock_blocking(eb);
1888
1889 btrfs_tree_unlock(parent);
1890 free_extent_buffer(parent);
1891
1892 parent = eb;
1893 continue;
1894 }
1895
1896 if (!cow) {
1897 btrfs_tree_unlock(parent);
1898 free_extent_buffer(parent);
1899 cow = 1;
1900 goto again;
1901 }
1902
1903 btrfs_node_key_to_cpu(path->nodes[level], &key,
1904 path->slots[level]);
1905 btrfs_release_path(path);
1906
1907 path->lowest_level = level;
1908 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1909 path->lowest_level = 0;
1910 BUG_ON(ret);
1911
1912 /*
1913 * Info qgroup to trace both subtrees.
1914 *
1915 * We must trace both trees.
1916 * 1) Tree reloc subtree
1917 * If not traced, we will leak data numbers
1918 * 2) Fs subtree
1919 * If not traced, we will double count old data
1920 * and tree block numbers, if current trans doesn't free
1921 * data reloc tree inode.
1922 */
1923 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1924 btrfs_header_generation(parent),
1925 btrfs_header_level(parent));
1926 if (ret < 0)
1927 break;
1928 ret = btrfs_qgroup_trace_subtree(trans, dest,
1929 path->nodes[level],
1930 btrfs_header_generation(path->nodes[level]),
1931 btrfs_header_level(path->nodes[level]));
1932 if (ret < 0)
1933 break;
1934
1935 /*
1936 * swap blocks in fs tree and reloc tree.
1937 */
1938 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1939 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1940 btrfs_mark_buffer_dirty(parent);
1941
1942 btrfs_set_node_blockptr(path->nodes[level],
1943 path->slots[level], old_bytenr);
1944 btrfs_set_node_ptr_generation(path->nodes[level],
1945 path->slots[level], old_ptr_gen);
1946 btrfs_mark_buffer_dirty(path->nodes[level]);
1947
1948 ret = btrfs_inc_extent_ref(trans, fs_info, old_bytenr,
1949 blocksize, path->nodes[level]->start,
1950 src->root_key.objectid, level - 1, 0);
1951 BUG_ON(ret);
1952 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1953 blocksize, 0, dest->root_key.objectid,
1954 level - 1, 0);
1955 BUG_ON(ret);
1956
1957 ret = btrfs_free_extent(trans, fs_info, new_bytenr, blocksize,
1958 path->nodes[level]->start,
1959 src->root_key.objectid, level - 1, 0);
1960 BUG_ON(ret);
1961
1962 ret = btrfs_free_extent(trans, fs_info, old_bytenr, blocksize,
1963 0, dest->root_key.objectid, level - 1,
1964 0);
1965 BUG_ON(ret);
1966
1967 btrfs_unlock_up_safe(path, 0);
1968
1969 ret = level;
1970 break;
1971 }
1972 btrfs_tree_unlock(parent);
1973 free_extent_buffer(parent);
1974 return ret;
1975 }
1976
1977 /*
1978 * helper to find next relocated block in reloc tree
1979 */
1980 static noinline_for_stack
1981 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1982 int *level)
1983 {
1984 struct extent_buffer *eb;
1985 int i;
1986 u64 last_snapshot;
1987 u32 nritems;
1988
1989 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1990
1991 for (i = 0; i < *level; i++) {
1992 free_extent_buffer(path->nodes[i]);
1993 path->nodes[i] = NULL;
1994 }
1995
1996 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1997 eb = path->nodes[i];
1998 nritems = btrfs_header_nritems(eb);
1999 while (path->slots[i] + 1 < nritems) {
2000 path->slots[i]++;
2001 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2002 last_snapshot)
2003 continue;
2004
2005 *level = i;
2006 return 0;
2007 }
2008 free_extent_buffer(path->nodes[i]);
2009 path->nodes[i] = NULL;
2010 }
2011 return 1;
2012 }
2013
2014 /*
2015 * walk down reloc tree to find relocated block of lowest level
2016 */
2017 static noinline_for_stack
2018 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2019 int *level)
2020 {
2021 struct btrfs_fs_info *fs_info = root->fs_info;
2022 struct extent_buffer *eb = NULL;
2023 int i;
2024 u64 bytenr;
2025 u64 ptr_gen = 0;
2026 u64 last_snapshot;
2027 u32 nritems;
2028
2029 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2030
2031 for (i = *level; i > 0; i--) {
2032 eb = path->nodes[i];
2033 nritems = btrfs_header_nritems(eb);
2034 while (path->slots[i] < nritems) {
2035 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2036 if (ptr_gen > last_snapshot)
2037 break;
2038 path->slots[i]++;
2039 }
2040 if (path->slots[i] >= nritems) {
2041 if (i == *level)
2042 break;
2043 *level = i + 1;
2044 return 0;
2045 }
2046 if (i == 1) {
2047 *level = i;
2048 return 0;
2049 }
2050
2051 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2052 eb = read_tree_block(fs_info, bytenr, ptr_gen);
2053 if (IS_ERR(eb)) {
2054 return PTR_ERR(eb);
2055 } else if (!extent_buffer_uptodate(eb)) {
2056 free_extent_buffer(eb);
2057 return -EIO;
2058 }
2059 BUG_ON(btrfs_header_level(eb) != i - 1);
2060 path->nodes[i - 1] = eb;
2061 path->slots[i - 1] = 0;
2062 }
2063 return 1;
2064 }
2065
2066 /*
2067 * invalidate extent cache for file extents whose key in range of
2068 * [min_key, max_key)
2069 */
2070 static int invalidate_extent_cache(struct btrfs_root *root,
2071 struct btrfs_key *min_key,
2072 struct btrfs_key *max_key)
2073 {
2074 struct btrfs_fs_info *fs_info = root->fs_info;
2075 struct inode *inode = NULL;
2076 u64 objectid;
2077 u64 start, end;
2078 u64 ino;
2079
2080 objectid = min_key->objectid;
2081 while (1) {
2082 cond_resched();
2083 iput(inode);
2084
2085 if (objectid > max_key->objectid)
2086 break;
2087
2088 inode = find_next_inode(root, objectid);
2089 if (!inode)
2090 break;
2091 ino = btrfs_ino(BTRFS_I(inode));
2092
2093 if (ino > max_key->objectid) {
2094 iput(inode);
2095 break;
2096 }
2097
2098 objectid = ino + 1;
2099 if (!S_ISREG(inode->i_mode))
2100 continue;
2101
2102 if (unlikely(min_key->objectid == ino)) {
2103 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2104 continue;
2105 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2106 start = 0;
2107 else {
2108 start = min_key->offset;
2109 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2110 }
2111 } else {
2112 start = 0;
2113 }
2114
2115 if (unlikely(max_key->objectid == ino)) {
2116 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2117 continue;
2118 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2119 end = (u64)-1;
2120 } else {
2121 if (max_key->offset == 0)
2122 continue;
2123 end = max_key->offset;
2124 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2125 end--;
2126 }
2127 } else {
2128 end = (u64)-1;
2129 }
2130
2131 /* the lock_extent waits for readpage to complete */
2132 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2133 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2134 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2135 }
2136 return 0;
2137 }
2138
2139 static int find_next_key(struct btrfs_path *path, int level,
2140 struct btrfs_key *key)
2141
2142 {
2143 while (level < BTRFS_MAX_LEVEL) {
2144 if (!path->nodes[level])
2145 break;
2146 if (path->slots[level] + 1 <
2147 btrfs_header_nritems(path->nodes[level])) {
2148 btrfs_node_key_to_cpu(path->nodes[level], key,
2149 path->slots[level] + 1);
2150 return 0;
2151 }
2152 level++;
2153 }
2154 return 1;
2155 }
2156
2157 /*
2158 * merge the relocated tree blocks in reloc tree with corresponding
2159 * fs tree.
2160 */
2161 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2162 struct btrfs_root *root)
2163 {
2164 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2165 LIST_HEAD(inode_list);
2166 struct btrfs_key key;
2167 struct btrfs_key next_key;
2168 struct btrfs_trans_handle *trans = NULL;
2169 struct btrfs_root *reloc_root;
2170 struct btrfs_root_item *root_item;
2171 struct btrfs_path *path;
2172 struct extent_buffer *leaf;
2173 int level;
2174 int max_level;
2175 int replaced = 0;
2176 int ret;
2177 int err = 0;
2178 u32 min_reserved;
2179
2180 path = btrfs_alloc_path();
2181 if (!path)
2182 return -ENOMEM;
2183 path->reada = READA_FORWARD;
2184
2185 reloc_root = root->reloc_root;
2186 root_item = &reloc_root->root_item;
2187
2188 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2189 level = btrfs_root_level(root_item);
2190 extent_buffer_get(reloc_root->node);
2191 path->nodes[level] = reloc_root->node;
2192 path->slots[level] = 0;
2193 } else {
2194 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2195
2196 level = root_item->drop_level;
2197 BUG_ON(level == 0);
2198 path->lowest_level = level;
2199 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2200 path->lowest_level = 0;
2201 if (ret < 0) {
2202 btrfs_free_path(path);
2203 return ret;
2204 }
2205
2206 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2207 path->slots[level]);
2208 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2209
2210 btrfs_unlock_up_safe(path, 0);
2211 }
2212
2213 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2214 memset(&next_key, 0, sizeof(next_key));
2215
2216 while (1) {
2217 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2218 BTRFS_RESERVE_FLUSH_ALL);
2219 if (ret) {
2220 err = ret;
2221 goto out;
2222 }
2223 trans = btrfs_start_transaction(root, 0);
2224 if (IS_ERR(trans)) {
2225 err = PTR_ERR(trans);
2226 trans = NULL;
2227 goto out;
2228 }
2229 trans->block_rsv = rc->block_rsv;
2230
2231 replaced = 0;
2232 max_level = level;
2233
2234 ret = walk_down_reloc_tree(reloc_root, path, &level);
2235 if (ret < 0) {
2236 err = ret;
2237 goto out;
2238 }
2239 if (ret > 0)
2240 break;
2241
2242 if (!find_next_key(path, level, &key) &&
2243 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2244 ret = 0;
2245 } else {
2246 ret = replace_path(trans, root, reloc_root, path,
2247 &next_key, level, max_level);
2248 }
2249 if (ret < 0) {
2250 err = ret;
2251 goto out;
2252 }
2253
2254 if (ret > 0) {
2255 level = ret;
2256 btrfs_node_key_to_cpu(path->nodes[level], &key,
2257 path->slots[level]);
2258 replaced = 1;
2259 }
2260
2261 ret = walk_up_reloc_tree(reloc_root, path, &level);
2262 if (ret > 0)
2263 break;
2264
2265 BUG_ON(level == 0);
2266 /*
2267 * save the merging progress in the drop_progress.
2268 * this is OK since root refs == 1 in this case.
2269 */
2270 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2271 path->slots[level]);
2272 root_item->drop_level = level;
2273
2274 btrfs_end_transaction_throttle(trans);
2275 trans = NULL;
2276
2277 btrfs_btree_balance_dirty(fs_info);
2278
2279 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2280 invalidate_extent_cache(root, &key, &next_key);
2281 }
2282
2283 /*
2284 * handle the case only one block in the fs tree need to be
2285 * relocated and the block is tree root.
2286 */
2287 leaf = btrfs_lock_root_node(root);
2288 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2289 btrfs_tree_unlock(leaf);
2290 free_extent_buffer(leaf);
2291 if (ret < 0)
2292 err = ret;
2293 out:
2294 btrfs_free_path(path);
2295
2296 if (err == 0) {
2297 memset(&root_item->drop_progress, 0,
2298 sizeof(root_item->drop_progress));
2299 root_item->drop_level = 0;
2300 btrfs_set_root_refs(root_item, 0);
2301 btrfs_update_reloc_root(trans, root);
2302 }
2303
2304 if (trans)
2305 btrfs_end_transaction_throttle(trans);
2306
2307 btrfs_btree_balance_dirty(fs_info);
2308
2309 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2310 invalidate_extent_cache(root, &key, &next_key);
2311
2312 return err;
2313 }
2314
2315 static noinline_for_stack
2316 int prepare_to_merge(struct reloc_control *rc, int err)
2317 {
2318 struct btrfs_root *root = rc->extent_root;
2319 struct btrfs_fs_info *fs_info = root->fs_info;
2320 struct btrfs_root *reloc_root;
2321 struct btrfs_trans_handle *trans;
2322 LIST_HEAD(reloc_roots);
2323 u64 num_bytes = 0;
2324 int ret;
2325
2326 mutex_lock(&fs_info->reloc_mutex);
2327 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2328 rc->merging_rsv_size += rc->nodes_relocated * 2;
2329 mutex_unlock(&fs_info->reloc_mutex);
2330
2331 again:
2332 if (!err) {
2333 num_bytes = rc->merging_rsv_size;
2334 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2335 BTRFS_RESERVE_FLUSH_ALL);
2336 if (ret)
2337 err = ret;
2338 }
2339
2340 trans = btrfs_join_transaction(rc->extent_root);
2341 if (IS_ERR(trans)) {
2342 if (!err)
2343 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2344 num_bytes);
2345 return PTR_ERR(trans);
2346 }
2347
2348 if (!err) {
2349 if (num_bytes != rc->merging_rsv_size) {
2350 btrfs_end_transaction(trans);
2351 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2352 num_bytes);
2353 goto again;
2354 }
2355 }
2356
2357 rc->merge_reloc_tree = 1;
2358
2359 while (!list_empty(&rc->reloc_roots)) {
2360 reloc_root = list_entry(rc->reloc_roots.next,
2361 struct btrfs_root, root_list);
2362 list_del_init(&reloc_root->root_list);
2363
2364 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2365 BUG_ON(IS_ERR(root));
2366 BUG_ON(root->reloc_root != reloc_root);
2367
2368 /*
2369 * set reference count to 1, so btrfs_recover_relocation
2370 * knows it should resumes merging
2371 */
2372 if (!err)
2373 btrfs_set_root_refs(&reloc_root->root_item, 1);
2374 btrfs_update_reloc_root(trans, root);
2375
2376 list_add(&reloc_root->root_list, &reloc_roots);
2377 }
2378
2379 list_splice(&reloc_roots, &rc->reloc_roots);
2380
2381 if (!err)
2382 btrfs_commit_transaction(trans);
2383 else
2384 btrfs_end_transaction(trans);
2385 return err;
2386 }
2387
2388 static noinline_for_stack
2389 void free_reloc_roots(struct list_head *list)
2390 {
2391 struct btrfs_root *reloc_root;
2392
2393 while (!list_empty(list)) {
2394 reloc_root = list_entry(list->next, struct btrfs_root,
2395 root_list);
2396 free_extent_buffer(reloc_root->node);
2397 free_extent_buffer(reloc_root->commit_root);
2398 reloc_root->node = NULL;
2399 reloc_root->commit_root = NULL;
2400 __del_reloc_root(reloc_root);
2401 }
2402 }
2403
2404 static noinline_for_stack
2405 void merge_reloc_roots(struct reloc_control *rc)
2406 {
2407 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2408 struct btrfs_root *root;
2409 struct btrfs_root *reloc_root;
2410 LIST_HEAD(reloc_roots);
2411 int found = 0;
2412 int ret = 0;
2413 again:
2414 root = rc->extent_root;
2415
2416 /*
2417 * this serializes us with btrfs_record_root_in_transaction,
2418 * we have to make sure nobody is in the middle of
2419 * adding their roots to the list while we are
2420 * doing this splice
2421 */
2422 mutex_lock(&fs_info->reloc_mutex);
2423 list_splice_init(&rc->reloc_roots, &reloc_roots);
2424 mutex_unlock(&fs_info->reloc_mutex);
2425
2426 while (!list_empty(&reloc_roots)) {
2427 found = 1;
2428 reloc_root = list_entry(reloc_roots.next,
2429 struct btrfs_root, root_list);
2430
2431 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2432 root = read_fs_root(fs_info,
2433 reloc_root->root_key.offset);
2434 BUG_ON(IS_ERR(root));
2435 BUG_ON(root->reloc_root != reloc_root);
2436
2437 ret = merge_reloc_root(rc, root);
2438 if (ret) {
2439 if (list_empty(&reloc_root->root_list))
2440 list_add_tail(&reloc_root->root_list,
2441 &reloc_roots);
2442 goto out;
2443 }
2444 } else {
2445 list_del_init(&reloc_root->root_list);
2446 }
2447
2448 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2449 if (ret < 0) {
2450 if (list_empty(&reloc_root->root_list))
2451 list_add_tail(&reloc_root->root_list,
2452 &reloc_roots);
2453 goto out;
2454 }
2455 }
2456
2457 if (found) {
2458 found = 0;
2459 goto again;
2460 }
2461 out:
2462 if (ret) {
2463 btrfs_handle_fs_error(fs_info, ret, NULL);
2464 if (!list_empty(&reloc_roots))
2465 free_reloc_roots(&reloc_roots);
2466
2467 /* new reloc root may be added */
2468 mutex_lock(&fs_info->reloc_mutex);
2469 list_splice_init(&rc->reloc_roots, &reloc_roots);
2470 mutex_unlock(&fs_info->reloc_mutex);
2471 if (!list_empty(&reloc_roots))
2472 free_reloc_roots(&reloc_roots);
2473 }
2474
2475 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2476 }
2477
2478 static void free_block_list(struct rb_root *blocks)
2479 {
2480 struct tree_block *block;
2481 struct rb_node *rb_node;
2482 while ((rb_node = rb_first(blocks))) {
2483 block = rb_entry(rb_node, struct tree_block, rb_node);
2484 rb_erase(rb_node, blocks);
2485 kfree(block);
2486 }
2487 }
2488
2489 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2490 struct btrfs_root *reloc_root)
2491 {
2492 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2493 struct btrfs_root *root;
2494
2495 if (reloc_root->last_trans == trans->transid)
2496 return 0;
2497
2498 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2499 BUG_ON(IS_ERR(root));
2500 BUG_ON(root->reloc_root != reloc_root);
2501
2502 return btrfs_record_root_in_trans(trans, root);
2503 }
2504
2505 static noinline_for_stack
2506 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2507 struct reloc_control *rc,
2508 struct backref_node *node,
2509 struct backref_edge *edges[])
2510 {
2511 struct backref_node *next;
2512 struct btrfs_root *root;
2513 int index = 0;
2514
2515 next = node;
2516 while (1) {
2517 cond_resched();
2518 next = walk_up_backref(next, edges, &index);
2519 root = next->root;
2520 BUG_ON(!root);
2521 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2522
2523 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2524 record_reloc_root_in_trans(trans, root);
2525 break;
2526 }
2527
2528 btrfs_record_root_in_trans(trans, root);
2529 root = root->reloc_root;
2530
2531 if (next->new_bytenr != root->node->start) {
2532 BUG_ON(next->new_bytenr);
2533 BUG_ON(!list_empty(&next->list));
2534 next->new_bytenr = root->node->start;
2535 next->root = root;
2536 list_add_tail(&next->list,
2537 &rc->backref_cache.changed);
2538 __mark_block_processed(rc, next);
2539 break;
2540 }
2541
2542 WARN_ON(1);
2543 root = NULL;
2544 next = walk_down_backref(edges, &index);
2545 if (!next || next->level <= node->level)
2546 break;
2547 }
2548 if (!root)
2549 return NULL;
2550
2551 next = node;
2552 /* setup backref node path for btrfs_reloc_cow_block */
2553 while (1) {
2554 rc->backref_cache.path[next->level] = next;
2555 if (--index < 0)
2556 break;
2557 next = edges[index]->node[UPPER];
2558 }
2559 return root;
2560 }
2561
2562 /*
2563 * select a tree root for relocation. return NULL if the block
2564 * is reference counted. we should use do_relocation() in this
2565 * case. return a tree root pointer if the block isn't reference
2566 * counted. return -ENOENT if the block is root of reloc tree.
2567 */
2568 static noinline_for_stack
2569 struct btrfs_root *select_one_root(struct backref_node *node)
2570 {
2571 struct backref_node *next;
2572 struct btrfs_root *root;
2573 struct btrfs_root *fs_root = NULL;
2574 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2575 int index = 0;
2576
2577 next = node;
2578 while (1) {
2579 cond_resched();
2580 next = walk_up_backref(next, edges, &index);
2581 root = next->root;
2582 BUG_ON(!root);
2583
2584 /* no other choice for non-references counted tree */
2585 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2586 return root;
2587
2588 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2589 fs_root = root;
2590
2591 if (next != node)
2592 return NULL;
2593
2594 next = walk_down_backref(edges, &index);
2595 if (!next || next->level <= node->level)
2596 break;
2597 }
2598
2599 if (!fs_root)
2600 return ERR_PTR(-ENOENT);
2601 return fs_root;
2602 }
2603
2604 static noinline_for_stack
2605 u64 calcu_metadata_size(struct reloc_control *rc,
2606 struct backref_node *node, int reserve)
2607 {
2608 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2609 struct backref_node *next = node;
2610 struct backref_edge *edge;
2611 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2612 u64 num_bytes = 0;
2613 int index = 0;
2614
2615 BUG_ON(reserve && node->processed);
2616
2617 while (next) {
2618 cond_resched();
2619 while (1) {
2620 if (next->processed && (reserve || next != node))
2621 break;
2622
2623 num_bytes += fs_info->nodesize;
2624
2625 if (list_empty(&next->upper))
2626 break;
2627
2628 edge = list_entry(next->upper.next,
2629 struct backref_edge, list[LOWER]);
2630 edges[index++] = edge;
2631 next = edge->node[UPPER];
2632 }
2633 next = walk_down_backref(edges, &index);
2634 }
2635 return num_bytes;
2636 }
2637
2638 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2639 struct reloc_control *rc,
2640 struct backref_node *node)
2641 {
2642 struct btrfs_root *root = rc->extent_root;
2643 struct btrfs_fs_info *fs_info = root->fs_info;
2644 u64 num_bytes;
2645 int ret;
2646 u64 tmp;
2647
2648 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2649
2650 trans->block_rsv = rc->block_rsv;
2651 rc->reserved_bytes += num_bytes;
2652
2653 /*
2654 * We are under a transaction here so we can only do limited flushing.
2655 * If we get an enospc just kick back -EAGAIN so we know to drop the
2656 * transaction and try to refill when we can flush all the things.
2657 */
2658 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2659 BTRFS_RESERVE_FLUSH_LIMIT);
2660 if (ret) {
2661 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2662 while (tmp <= rc->reserved_bytes)
2663 tmp <<= 1;
2664 /*
2665 * only one thread can access block_rsv at this point,
2666 * so we don't need hold lock to protect block_rsv.
2667 * we expand more reservation size here to allow enough
2668 * space for relocation and we will return eailer in
2669 * enospc case.
2670 */
2671 rc->block_rsv->size = tmp + fs_info->nodesize *
2672 RELOCATION_RESERVED_NODES;
2673 return -EAGAIN;
2674 }
2675
2676 return 0;
2677 }
2678
2679 /*
2680 * relocate a block tree, and then update pointers in upper level
2681 * blocks that reference the block to point to the new location.
2682 *
2683 * if called by link_to_upper, the block has already been relocated.
2684 * in that case this function just updates pointers.
2685 */
2686 static int do_relocation(struct btrfs_trans_handle *trans,
2687 struct reloc_control *rc,
2688 struct backref_node *node,
2689 struct btrfs_key *key,
2690 struct btrfs_path *path, int lowest)
2691 {
2692 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2693 struct backref_node *upper;
2694 struct backref_edge *edge;
2695 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2696 struct btrfs_root *root;
2697 struct extent_buffer *eb;
2698 u32 blocksize;
2699 u64 bytenr;
2700 u64 generation;
2701 int slot;
2702 int ret;
2703 int err = 0;
2704
2705 BUG_ON(lowest && node->eb);
2706
2707 path->lowest_level = node->level + 1;
2708 rc->backref_cache.path[node->level] = node;
2709 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2710 cond_resched();
2711
2712 upper = edge->node[UPPER];
2713 root = select_reloc_root(trans, rc, upper, edges);
2714 BUG_ON(!root);
2715
2716 if (upper->eb && !upper->locked) {
2717 if (!lowest) {
2718 ret = btrfs_bin_search(upper->eb, key,
2719 upper->level, &slot);
2720 BUG_ON(ret);
2721 bytenr = btrfs_node_blockptr(upper->eb, slot);
2722 if (node->eb->start == bytenr)
2723 goto next;
2724 }
2725 drop_node_buffer(upper);
2726 }
2727
2728 if (!upper->eb) {
2729 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2730 if (ret) {
2731 if (ret < 0)
2732 err = ret;
2733 else
2734 err = -ENOENT;
2735
2736 btrfs_release_path(path);
2737 break;
2738 }
2739
2740 if (!upper->eb) {
2741 upper->eb = path->nodes[upper->level];
2742 path->nodes[upper->level] = NULL;
2743 } else {
2744 BUG_ON(upper->eb != path->nodes[upper->level]);
2745 }
2746
2747 upper->locked = 1;
2748 path->locks[upper->level] = 0;
2749
2750 slot = path->slots[upper->level];
2751 btrfs_release_path(path);
2752 } else {
2753 ret = btrfs_bin_search(upper->eb, key, upper->level,
2754 &slot);
2755 BUG_ON(ret);
2756 }
2757
2758 bytenr = btrfs_node_blockptr(upper->eb, slot);
2759 if (lowest) {
2760 if (bytenr != node->bytenr) {
2761 btrfs_err(root->fs_info,
2762 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2763 bytenr, node->bytenr, slot,
2764 upper->eb->start);
2765 err = -EIO;
2766 goto next;
2767 }
2768 } else {
2769 if (node->eb->start == bytenr)
2770 goto next;
2771 }
2772
2773 blocksize = root->fs_info->nodesize;
2774 generation = btrfs_node_ptr_generation(upper->eb, slot);
2775 eb = read_tree_block(fs_info, bytenr, generation);
2776 if (IS_ERR(eb)) {
2777 err = PTR_ERR(eb);
2778 goto next;
2779 } else if (!extent_buffer_uptodate(eb)) {
2780 free_extent_buffer(eb);
2781 err = -EIO;
2782 goto next;
2783 }
2784 btrfs_tree_lock(eb);
2785 btrfs_set_lock_blocking(eb);
2786
2787 if (!node->eb) {
2788 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2789 slot, &eb);
2790 btrfs_tree_unlock(eb);
2791 free_extent_buffer(eb);
2792 if (ret < 0) {
2793 err = ret;
2794 goto next;
2795 }
2796 BUG_ON(node->eb != eb);
2797 } else {
2798 btrfs_set_node_blockptr(upper->eb, slot,
2799 node->eb->start);
2800 btrfs_set_node_ptr_generation(upper->eb, slot,
2801 trans->transid);
2802 btrfs_mark_buffer_dirty(upper->eb);
2803
2804 ret = btrfs_inc_extent_ref(trans, root->fs_info,
2805 node->eb->start, blocksize,
2806 upper->eb->start,
2807 btrfs_header_owner(upper->eb),
2808 node->level, 0);
2809 BUG_ON(ret);
2810
2811 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2812 BUG_ON(ret);
2813 }
2814 next:
2815 if (!upper->pending)
2816 drop_node_buffer(upper);
2817 else
2818 unlock_node_buffer(upper);
2819 if (err)
2820 break;
2821 }
2822
2823 if (!err && node->pending) {
2824 drop_node_buffer(node);
2825 list_move_tail(&node->list, &rc->backref_cache.changed);
2826 node->pending = 0;
2827 }
2828
2829 path->lowest_level = 0;
2830 BUG_ON(err == -ENOSPC);
2831 return err;
2832 }
2833
2834 static int link_to_upper(struct btrfs_trans_handle *trans,
2835 struct reloc_control *rc,
2836 struct backref_node *node,
2837 struct btrfs_path *path)
2838 {
2839 struct btrfs_key key;
2840
2841 btrfs_node_key_to_cpu(node->eb, &key, 0);
2842 return do_relocation(trans, rc, node, &key, path, 0);
2843 }
2844
2845 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2846 struct reloc_control *rc,
2847 struct btrfs_path *path, int err)
2848 {
2849 LIST_HEAD(list);
2850 struct backref_cache *cache = &rc->backref_cache;
2851 struct backref_node *node;
2852 int level;
2853 int ret;
2854
2855 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2856 while (!list_empty(&cache->pending[level])) {
2857 node = list_entry(cache->pending[level].next,
2858 struct backref_node, list);
2859 list_move_tail(&node->list, &list);
2860 BUG_ON(!node->pending);
2861
2862 if (!err) {
2863 ret = link_to_upper(trans, rc, node, path);
2864 if (ret < 0)
2865 err = ret;
2866 }
2867 }
2868 list_splice_init(&list, &cache->pending[level]);
2869 }
2870 return err;
2871 }
2872
2873 static void mark_block_processed(struct reloc_control *rc,
2874 u64 bytenr, u32 blocksize)
2875 {
2876 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2877 EXTENT_DIRTY);
2878 }
2879
2880 static void __mark_block_processed(struct reloc_control *rc,
2881 struct backref_node *node)
2882 {
2883 u32 blocksize;
2884 if (node->level == 0 ||
2885 in_block_group(node->bytenr, rc->block_group)) {
2886 blocksize = rc->extent_root->fs_info->nodesize;
2887 mark_block_processed(rc, node->bytenr, blocksize);
2888 }
2889 node->processed = 1;
2890 }
2891
2892 /*
2893 * mark a block and all blocks directly/indirectly reference the block
2894 * as processed.
2895 */
2896 static void update_processed_blocks(struct reloc_control *rc,
2897 struct backref_node *node)
2898 {
2899 struct backref_node *next = node;
2900 struct backref_edge *edge;
2901 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2902 int index = 0;
2903
2904 while (next) {
2905 cond_resched();
2906 while (1) {
2907 if (next->processed)
2908 break;
2909
2910 __mark_block_processed(rc, next);
2911
2912 if (list_empty(&next->upper))
2913 break;
2914
2915 edge = list_entry(next->upper.next,
2916 struct backref_edge, list[LOWER]);
2917 edges[index++] = edge;
2918 next = edge->node[UPPER];
2919 }
2920 next = walk_down_backref(edges, &index);
2921 }
2922 }
2923
2924 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2925 {
2926 u32 blocksize = rc->extent_root->fs_info->nodesize;
2927
2928 if (test_range_bit(&rc->processed_blocks, bytenr,
2929 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2930 return 1;
2931 return 0;
2932 }
2933
2934 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2935 struct tree_block *block)
2936 {
2937 struct extent_buffer *eb;
2938
2939 BUG_ON(block->key_ready);
2940 eb = read_tree_block(fs_info, block->bytenr, block->key.offset);
2941 if (IS_ERR(eb)) {
2942 return PTR_ERR(eb);
2943 } else if (!extent_buffer_uptodate(eb)) {
2944 free_extent_buffer(eb);
2945 return -EIO;
2946 }
2947 WARN_ON(btrfs_header_level(eb) != block->level);
2948 if (block->level == 0)
2949 btrfs_item_key_to_cpu(eb, &block->key, 0);
2950 else
2951 btrfs_node_key_to_cpu(eb, &block->key, 0);
2952 free_extent_buffer(eb);
2953 block->key_ready = 1;
2954 return 0;
2955 }
2956
2957 /*
2958 * helper function to relocate a tree block
2959 */
2960 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2961 struct reloc_control *rc,
2962 struct backref_node *node,
2963 struct btrfs_key *key,
2964 struct btrfs_path *path)
2965 {
2966 struct btrfs_root *root;
2967 int ret = 0;
2968
2969 if (!node)
2970 return 0;
2971
2972 BUG_ON(node->processed);
2973 root = select_one_root(node);
2974 if (root == ERR_PTR(-ENOENT)) {
2975 update_processed_blocks(rc, node);
2976 goto out;
2977 }
2978
2979 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2980 ret = reserve_metadata_space(trans, rc, node);
2981 if (ret)
2982 goto out;
2983 }
2984
2985 if (root) {
2986 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2987 BUG_ON(node->new_bytenr);
2988 BUG_ON(!list_empty(&node->list));
2989 btrfs_record_root_in_trans(trans, root);
2990 root = root->reloc_root;
2991 node->new_bytenr = root->node->start;
2992 node->root = root;
2993 list_add_tail(&node->list, &rc->backref_cache.changed);
2994 } else {
2995 path->lowest_level = node->level;
2996 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2997 btrfs_release_path(path);
2998 if (ret > 0)
2999 ret = 0;
3000 }
3001 if (!ret)
3002 update_processed_blocks(rc, node);
3003 } else {
3004 ret = do_relocation(trans, rc, node, key, path, 1);
3005 }
3006 out:
3007 if (ret || node->level == 0 || node->cowonly)
3008 remove_backref_node(&rc->backref_cache, node);
3009 return ret;
3010 }
3011
3012 /*
3013 * relocate a list of blocks
3014 */
3015 static noinline_for_stack
3016 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3017 struct reloc_control *rc, struct rb_root *blocks)
3018 {
3019 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3020 struct backref_node *node;
3021 struct btrfs_path *path;
3022 struct tree_block *block;
3023 struct rb_node *rb_node;
3024 int ret;
3025 int err = 0;
3026
3027 path = btrfs_alloc_path();
3028 if (!path) {
3029 err = -ENOMEM;
3030 goto out_free_blocks;
3031 }
3032
3033 rb_node = rb_first(blocks);
3034 while (rb_node) {
3035 block = rb_entry(rb_node, struct tree_block, rb_node);
3036 if (!block->key_ready)
3037 readahead_tree_block(fs_info, block->bytenr);
3038 rb_node = rb_next(rb_node);
3039 }
3040
3041 rb_node = rb_first(blocks);
3042 while (rb_node) {
3043 block = rb_entry(rb_node, struct tree_block, rb_node);
3044 if (!block->key_ready) {
3045 err = get_tree_block_key(fs_info, block);
3046 if (err)
3047 goto out_free_path;
3048 }
3049 rb_node = rb_next(rb_node);
3050 }
3051
3052 rb_node = rb_first(blocks);
3053 while (rb_node) {
3054 block = rb_entry(rb_node, struct tree_block, rb_node);
3055
3056 node = build_backref_tree(rc, &block->key,
3057 block->level, block->bytenr);
3058 if (IS_ERR(node)) {
3059 err = PTR_ERR(node);
3060 goto out;
3061 }
3062
3063 ret = relocate_tree_block(trans, rc, node, &block->key,
3064 path);
3065 if (ret < 0) {
3066 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3067 err = ret;
3068 goto out;
3069 }
3070 rb_node = rb_next(rb_node);
3071 }
3072 out:
3073 err = finish_pending_nodes(trans, rc, path, err);
3074
3075 out_free_path:
3076 btrfs_free_path(path);
3077 out_free_blocks:
3078 free_block_list(blocks);
3079 return err;
3080 }
3081
3082 static noinline_for_stack
3083 int prealloc_file_extent_cluster(struct inode *inode,
3084 struct file_extent_cluster *cluster)
3085 {
3086 u64 alloc_hint = 0;
3087 u64 start;
3088 u64 end;
3089 u64 offset = BTRFS_I(inode)->index_cnt;
3090 u64 num_bytes;
3091 int nr = 0;
3092 int ret = 0;
3093 u64 prealloc_start = cluster->start - offset;
3094 u64 prealloc_end = cluster->end - offset;
3095 u64 cur_offset;
3096
3097 BUG_ON(cluster->start != cluster->boundary[0]);
3098 inode_lock(inode);
3099
3100 ret = btrfs_check_data_free_space(inode, prealloc_start,
3101 prealloc_end + 1 - prealloc_start);
3102 if (ret)
3103 goto out;
3104
3105 cur_offset = prealloc_start;
3106 while (nr < cluster->nr) {
3107 start = cluster->boundary[nr] - offset;
3108 if (nr + 1 < cluster->nr)
3109 end = cluster->boundary[nr + 1] - 1 - offset;
3110 else
3111 end = cluster->end - offset;
3112
3113 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3114 num_bytes = end + 1 - start;
3115 if (cur_offset < start)
3116 btrfs_free_reserved_data_space(inode, cur_offset,
3117 start - cur_offset);
3118 ret = btrfs_prealloc_file_range(inode, 0, start,
3119 num_bytes, num_bytes,
3120 end + 1, &alloc_hint);
3121 cur_offset = end + 1;
3122 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3123 if (ret)
3124 break;
3125 nr++;
3126 }
3127 if (cur_offset < prealloc_end)
3128 btrfs_free_reserved_data_space(inode, cur_offset,
3129 prealloc_end + 1 - cur_offset);
3130 out:
3131 inode_unlock(inode);
3132 return ret;
3133 }
3134
3135 static noinline_for_stack
3136 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3137 u64 block_start)
3138 {
3139 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3140 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3141 struct extent_map *em;
3142 int ret = 0;
3143
3144 em = alloc_extent_map();
3145 if (!em)
3146 return -ENOMEM;
3147
3148 em->start = start;
3149 em->len = end + 1 - start;
3150 em->block_len = em->len;
3151 em->block_start = block_start;
3152 em->bdev = fs_info->fs_devices->latest_bdev;
3153 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3154
3155 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3156 while (1) {
3157 write_lock(&em_tree->lock);
3158 ret = add_extent_mapping(em_tree, em, 0);
3159 write_unlock(&em_tree->lock);
3160 if (ret != -EEXIST) {
3161 free_extent_map(em);
3162 break;
3163 }
3164 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3165 }
3166 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3167 return ret;
3168 }
3169
3170 static int relocate_file_extent_cluster(struct inode *inode,
3171 struct file_extent_cluster *cluster)
3172 {
3173 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3174 u64 page_start;
3175 u64 page_end;
3176 u64 offset = BTRFS_I(inode)->index_cnt;
3177 unsigned long index;
3178 unsigned long last_index;
3179 struct page *page;
3180 struct file_ra_state *ra;
3181 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3182 int nr = 0;
3183 int ret = 0;
3184
3185 if (!cluster->nr)
3186 return 0;
3187
3188 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3189 if (!ra)
3190 return -ENOMEM;
3191
3192 ret = prealloc_file_extent_cluster(inode, cluster);
3193 if (ret)
3194 goto out;
3195
3196 file_ra_state_init(ra, inode->i_mapping);
3197
3198 ret = setup_extent_mapping(inode, cluster->start - offset,
3199 cluster->end - offset, cluster->start);
3200 if (ret)
3201 goto out;
3202
3203 index = (cluster->start - offset) >> PAGE_SHIFT;
3204 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3205 while (index <= last_index) {
3206 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3207 PAGE_SIZE);
3208 if (ret)
3209 goto out;
3210
3211 page = find_lock_page(inode->i_mapping, index);
3212 if (!page) {
3213 page_cache_sync_readahead(inode->i_mapping,
3214 ra, NULL, index,
3215 last_index + 1 - index);
3216 page = find_or_create_page(inode->i_mapping, index,
3217 mask);
3218 if (!page) {
3219 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3220 PAGE_SIZE);
3221 ret = -ENOMEM;
3222 goto out;
3223 }
3224 }
3225
3226 if (PageReadahead(page)) {
3227 page_cache_async_readahead(inode->i_mapping,
3228 ra, NULL, page, index,
3229 last_index + 1 - index);
3230 }
3231
3232 if (!PageUptodate(page)) {
3233 btrfs_readpage(NULL, page);
3234 lock_page(page);
3235 if (!PageUptodate(page)) {
3236 unlock_page(page);
3237 put_page(page);
3238 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3239 PAGE_SIZE);
3240 ret = -EIO;
3241 goto out;
3242 }
3243 }
3244
3245 page_start = page_offset(page);
3246 page_end = page_start + PAGE_SIZE - 1;
3247
3248 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3249
3250 set_page_extent_mapped(page);
3251
3252 if (nr < cluster->nr &&
3253 page_start + offset == cluster->boundary[nr]) {
3254 set_extent_bits(&BTRFS_I(inode)->io_tree,
3255 page_start, page_end,
3256 EXTENT_BOUNDARY);
3257 nr++;
3258 }
3259
3260 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL, 0);
3261 set_page_dirty(page);
3262
3263 unlock_extent(&BTRFS_I(inode)->io_tree,
3264 page_start, page_end);
3265 unlock_page(page);
3266 put_page(page);
3267
3268 index++;
3269 balance_dirty_pages_ratelimited(inode->i_mapping);
3270 btrfs_throttle(fs_info);
3271 }
3272 WARN_ON(nr != cluster->nr);
3273 out:
3274 kfree(ra);
3275 return ret;
3276 }
3277
3278 static noinline_for_stack
3279 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3280 struct file_extent_cluster *cluster)
3281 {
3282 int ret;
3283
3284 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3285 ret = relocate_file_extent_cluster(inode, cluster);
3286 if (ret)
3287 return ret;
3288 cluster->nr = 0;
3289 }
3290
3291 if (!cluster->nr)
3292 cluster->start = extent_key->objectid;
3293 else
3294 BUG_ON(cluster->nr >= MAX_EXTENTS);
3295 cluster->end = extent_key->objectid + extent_key->offset - 1;
3296 cluster->boundary[cluster->nr] = extent_key->objectid;
3297 cluster->nr++;
3298
3299 if (cluster->nr >= MAX_EXTENTS) {
3300 ret = relocate_file_extent_cluster(inode, cluster);
3301 if (ret)
3302 return ret;
3303 cluster->nr = 0;
3304 }
3305 return 0;
3306 }
3307
3308 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3309 static int get_ref_objectid_v0(struct reloc_control *rc,
3310 struct btrfs_path *path,
3311 struct btrfs_key *extent_key,
3312 u64 *ref_objectid, int *path_change)
3313 {
3314 struct btrfs_key key;
3315 struct extent_buffer *leaf;
3316 struct btrfs_extent_ref_v0 *ref0;
3317 int ret;
3318 int slot;
3319
3320 leaf = path->nodes[0];
3321 slot = path->slots[0];
3322 while (1) {
3323 if (slot >= btrfs_header_nritems(leaf)) {
3324 ret = btrfs_next_leaf(rc->extent_root, path);
3325 if (ret < 0)
3326 return ret;
3327 BUG_ON(ret > 0);
3328 leaf = path->nodes[0];
3329 slot = path->slots[0];
3330 if (path_change)
3331 *path_change = 1;
3332 }
3333 btrfs_item_key_to_cpu(leaf, &key, slot);
3334 if (key.objectid != extent_key->objectid)
3335 return -ENOENT;
3336
3337 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3338 slot++;
3339 continue;
3340 }
3341 ref0 = btrfs_item_ptr(leaf, slot,
3342 struct btrfs_extent_ref_v0);
3343 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3344 break;
3345 }
3346 return 0;
3347 }
3348 #endif
3349
3350 /*
3351 * helper to add a tree block to the list.
3352 * the major work is getting the generation and level of the block
3353 */
3354 static int add_tree_block(struct reloc_control *rc,
3355 struct btrfs_key *extent_key,
3356 struct btrfs_path *path,
3357 struct rb_root *blocks)
3358 {
3359 struct extent_buffer *eb;
3360 struct btrfs_extent_item *ei;
3361 struct btrfs_tree_block_info *bi;
3362 struct tree_block *block;
3363 struct rb_node *rb_node;
3364 u32 item_size;
3365 int level = -1;
3366 u64 generation;
3367
3368 eb = path->nodes[0];
3369 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3370
3371 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3372 item_size >= sizeof(*ei) + sizeof(*bi)) {
3373 ei = btrfs_item_ptr(eb, path->slots[0],
3374 struct btrfs_extent_item);
3375 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3376 bi = (struct btrfs_tree_block_info *)(ei + 1);
3377 level = btrfs_tree_block_level(eb, bi);
3378 } else {
3379 level = (int)extent_key->offset;
3380 }
3381 generation = btrfs_extent_generation(eb, ei);
3382 } else {
3383 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3384 u64 ref_owner;
3385 int ret;
3386
3387 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3388 ret = get_ref_objectid_v0(rc, path, extent_key,
3389 &ref_owner, NULL);
3390 if (ret < 0)
3391 return ret;
3392 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3393 level = (int)ref_owner;
3394 /* FIXME: get real generation */
3395 generation = 0;
3396 #else
3397 BUG();
3398 #endif
3399 }
3400
3401 btrfs_release_path(path);
3402
3403 BUG_ON(level == -1);
3404
3405 block = kmalloc(sizeof(*block), GFP_NOFS);
3406 if (!block)
3407 return -ENOMEM;
3408
3409 block->bytenr = extent_key->objectid;
3410 block->key.objectid = rc->extent_root->fs_info->nodesize;
3411 block->key.offset = generation;
3412 block->level = level;
3413 block->key_ready = 0;
3414
3415 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3416 if (rb_node)
3417 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3418
3419 return 0;
3420 }
3421
3422 /*
3423 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3424 */
3425 static int __add_tree_block(struct reloc_control *rc,
3426 u64 bytenr, u32 blocksize,
3427 struct rb_root *blocks)
3428 {
3429 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3430 struct btrfs_path *path;
3431 struct btrfs_key key;
3432 int ret;
3433 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3434
3435 if (tree_block_processed(bytenr, rc))
3436 return 0;
3437
3438 if (tree_search(blocks, bytenr))
3439 return 0;
3440
3441 path = btrfs_alloc_path();
3442 if (!path)
3443 return -ENOMEM;
3444 again:
3445 key.objectid = bytenr;
3446 if (skinny) {
3447 key.type = BTRFS_METADATA_ITEM_KEY;
3448 key.offset = (u64)-1;
3449 } else {
3450 key.type = BTRFS_EXTENT_ITEM_KEY;
3451 key.offset = blocksize;
3452 }
3453
3454 path->search_commit_root = 1;
3455 path->skip_locking = 1;
3456 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3457 if (ret < 0)
3458 goto out;
3459
3460 if (ret > 0 && skinny) {
3461 if (path->slots[0]) {
3462 path->slots[0]--;
3463 btrfs_item_key_to_cpu(path->nodes[0], &key,
3464 path->slots[0]);
3465 if (key.objectid == bytenr &&
3466 (key.type == BTRFS_METADATA_ITEM_KEY ||
3467 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3468 key.offset == blocksize)))
3469 ret = 0;
3470 }
3471
3472 if (ret) {
3473 skinny = false;
3474 btrfs_release_path(path);
3475 goto again;
3476 }
3477 }
3478 BUG_ON(ret);
3479
3480 ret = add_tree_block(rc, &key, path, blocks);
3481 out:
3482 btrfs_free_path(path);
3483 return ret;
3484 }
3485
3486 /*
3487 * helper to check if the block use full backrefs for pointers in it
3488 */
3489 static int block_use_full_backref(struct reloc_control *rc,
3490 struct extent_buffer *eb)
3491 {
3492 u64 flags;
3493 int ret;
3494
3495 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3496 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3497 return 1;
3498
3499 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3500 eb->start, btrfs_header_level(eb), 1,
3501 NULL, &flags);
3502 BUG_ON(ret);
3503
3504 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3505 ret = 1;
3506 else
3507 ret = 0;
3508 return ret;
3509 }
3510
3511 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3512 struct btrfs_block_group_cache *block_group,
3513 struct inode *inode,
3514 u64 ino)
3515 {
3516 struct btrfs_key key;
3517 struct btrfs_root *root = fs_info->tree_root;
3518 struct btrfs_trans_handle *trans;
3519 int ret = 0;
3520
3521 if (inode)
3522 goto truncate;
3523
3524 key.objectid = ino;
3525 key.type = BTRFS_INODE_ITEM_KEY;
3526 key.offset = 0;
3527
3528 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3529 if (IS_ERR(inode) || is_bad_inode(inode)) {
3530 if (!IS_ERR(inode))
3531 iput(inode);
3532 return -ENOENT;
3533 }
3534
3535 truncate:
3536 ret = btrfs_check_trunc_cache_free_space(fs_info,
3537 &fs_info->global_block_rsv);
3538 if (ret)
3539 goto out;
3540
3541 trans = btrfs_join_transaction(root);
3542 if (IS_ERR(trans)) {
3543 ret = PTR_ERR(trans);
3544 goto out;
3545 }
3546
3547 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3548
3549 btrfs_end_transaction(trans);
3550 btrfs_btree_balance_dirty(fs_info);
3551 out:
3552 iput(inode);
3553 return ret;
3554 }
3555
3556 /*
3557 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3558 * this function scans fs tree to find blocks reference the data extent
3559 */
3560 static int find_data_references(struct reloc_control *rc,
3561 struct btrfs_key *extent_key,
3562 struct extent_buffer *leaf,
3563 struct btrfs_extent_data_ref *ref,
3564 struct rb_root *blocks)
3565 {
3566 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3567 struct btrfs_path *path;
3568 struct tree_block *block;
3569 struct btrfs_root *root;
3570 struct btrfs_file_extent_item *fi;
3571 struct rb_node *rb_node;
3572 struct btrfs_key key;
3573 u64 ref_root;
3574 u64 ref_objectid;
3575 u64 ref_offset;
3576 u32 ref_count;
3577 u32 nritems;
3578 int err = 0;
3579 int added = 0;
3580 int counted;
3581 int ret;
3582
3583 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3584 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3585 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3586 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3587
3588 /*
3589 * This is an extent belonging to the free space cache, lets just delete
3590 * it and redo the search.
3591 */
3592 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3593 ret = delete_block_group_cache(fs_info, rc->block_group,
3594 NULL, ref_objectid);
3595 if (ret != -ENOENT)
3596 return ret;
3597 ret = 0;
3598 }
3599
3600 path = btrfs_alloc_path();
3601 if (!path)
3602 return -ENOMEM;
3603 path->reada = READA_FORWARD;
3604
3605 root = read_fs_root(fs_info, ref_root);
3606 if (IS_ERR(root)) {
3607 err = PTR_ERR(root);
3608 goto out;
3609 }
3610
3611 key.objectid = ref_objectid;
3612 key.type = BTRFS_EXTENT_DATA_KEY;
3613 if (ref_offset > ((u64)-1 << 32))
3614 key.offset = 0;
3615 else
3616 key.offset = ref_offset;
3617
3618 path->search_commit_root = 1;
3619 path->skip_locking = 1;
3620 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3621 if (ret < 0) {
3622 err = ret;
3623 goto out;
3624 }
3625
3626 leaf = path->nodes[0];
3627 nritems = btrfs_header_nritems(leaf);
3628 /*
3629 * the references in tree blocks that use full backrefs
3630 * are not counted in
3631 */
3632 if (block_use_full_backref(rc, leaf))
3633 counted = 0;
3634 else
3635 counted = 1;
3636 rb_node = tree_search(blocks, leaf->start);
3637 if (rb_node) {
3638 if (counted)
3639 added = 1;
3640 else
3641 path->slots[0] = nritems;
3642 }
3643
3644 while (ref_count > 0) {
3645 while (path->slots[0] >= nritems) {
3646 ret = btrfs_next_leaf(root, path);
3647 if (ret < 0) {
3648 err = ret;
3649 goto out;
3650 }
3651 if (WARN_ON(ret > 0))
3652 goto out;
3653
3654 leaf = path->nodes[0];
3655 nritems = btrfs_header_nritems(leaf);
3656 added = 0;
3657
3658 if (block_use_full_backref(rc, leaf))
3659 counted = 0;
3660 else
3661 counted = 1;
3662 rb_node = tree_search(blocks, leaf->start);
3663 if (rb_node) {
3664 if (counted)
3665 added = 1;
3666 else
3667 path->slots[0] = nritems;
3668 }
3669 }
3670
3671 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3672 if (WARN_ON(key.objectid != ref_objectid ||
3673 key.type != BTRFS_EXTENT_DATA_KEY))
3674 break;
3675
3676 fi = btrfs_item_ptr(leaf, path->slots[0],
3677 struct btrfs_file_extent_item);
3678
3679 if (btrfs_file_extent_type(leaf, fi) ==
3680 BTRFS_FILE_EXTENT_INLINE)
3681 goto next;
3682
3683 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3684 extent_key->objectid)
3685 goto next;
3686
3687 key.offset -= btrfs_file_extent_offset(leaf, fi);
3688 if (key.offset != ref_offset)
3689 goto next;
3690
3691 if (counted)
3692 ref_count--;
3693 if (added)
3694 goto next;
3695
3696 if (!tree_block_processed(leaf->start, rc)) {
3697 block = kmalloc(sizeof(*block), GFP_NOFS);
3698 if (!block) {
3699 err = -ENOMEM;
3700 break;
3701 }
3702 block->bytenr = leaf->start;
3703 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3704 block->level = 0;
3705 block->key_ready = 1;
3706 rb_node = tree_insert(blocks, block->bytenr,
3707 &block->rb_node);
3708 if (rb_node)
3709 backref_tree_panic(rb_node, -EEXIST,
3710 block->bytenr);
3711 }
3712 if (counted)
3713 added = 1;
3714 else
3715 path->slots[0] = nritems;
3716 next:
3717 path->slots[0]++;
3718
3719 }
3720 out:
3721 btrfs_free_path(path);
3722 return err;
3723 }
3724
3725 /*
3726 * helper to find all tree blocks that reference a given data extent
3727 */
3728 static noinline_for_stack
3729 int add_data_references(struct reloc_control *rc,
3730 struct btrfs_key *extent_key,
3731 struct btrfs_path *path,
3732 struct rb_root *blocks)
3733 {
3734 struct btrfs_key key;
3735 struct extent_buffer *eb;
3736 struct btrfs_extent_data_ref *dref;
3737 struct btrfs_extent_inline_ref *iref;
3738 unsigned long ptr;
3739 unsigned long end;
3740 u32 blocksize = rc->extent_root->fs_info->nodesize;
3741 int ret = 0;
3742 int err = 0;
3743
3744 eb = path->nodes[0];
3745 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3746 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3747 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3748 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3749 ptr = end;
3750 else
3751 #endif
3752 ptr += sizeof(struct btrfs_extent_item);
3753
3754 while (ptr < end) {
3755 iref = (struct btrfs_extent_inline_ref *)ptr;
3756 key.type = btrfs_extent_inline_ref_type(eb, iref);
3757 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3758 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3759 ret = __add_tree_block(rc, key.offset, blocksize,
3760 blocks);
3761 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3762 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3763 ret = find_data_references(rc, extent_key,
3764 eb, dref, blocks);
3765 } else {
3766 BUG();
3767 }
3768 if (ret) {
3769 err = ret;
3770 goto out;
3771 }
3772 ptr += btrfs_extent_inline_ref_size(key.type);
3773 }
3774 WARN_ON(ptr > end);
3775
3776 while (1) {
3777 cond_resched();
3778 eb = path->nodes[0];
3779 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3780 ret = btrfs_next_leaf(rc->extent_root, path);
3781 if (ret < 0) {
3782 err = ret;
3783 break;
3784 }
3785 if (ret > 0)
3786 break;
3787 eb = path->nodes[0];
3788 }
3789
3790 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3791 if (key.objectid != extent_key->objectid)
3792 break;
3793
3794 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3795 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3796 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3797 #else
3798 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3799 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3800 #endif
3801 ret = __add_tree_block(rc, key.offset, blocksize,
3802 blocks);
3803 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3804 dref = btrfs_item_ptr(eb, path->slots[0],
3805 struct btrfs_extent_data_ref);
3806 ret = find_data_references(rc, extent_key,
3807 eb, dref, blocks);
3808 } else {
3809 ret = 0;
3810 }
3811 if (ret) {
3812 err = ret;
3813 break;
3814 }
3815 path->slots[0]++;
3816 }
3817 out:
3818 btrfs_release_path(path);
3819 if (err)
3820 free_block_list(blocks);
3821 return err;
3822 }
3823
3824 /*
3825 * helper to find next unprocessed extent
3826 */
3827 static noinline_for_stack
3828 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3829 struct btrfs_key *extent_key)
3830 {
3831 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3832 struct btrfs_key key;
3833 struct extent_buffer *leaf;
3834 u64 start, end, last;
3835 int ret;
3836
3837 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3838 while (1) {
3839 cond_resched();
3840 if (rc->search_start >= last) {
3841 ret = 1;
3842 break;
3843 }
3844
3845 key.objectid = rc->search_start;
3846 key.type = BTRFS_EXTENT_ITEM_KEY;
3847 key.offset = 0;
3848
3849 path->search_commit_root = 1;
3850 path->skip_locking = 1;
3851 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3852 0, 0);
3853 if (ret < 0)
3854 break;
3855 next:
3856 leaf = path->nodes[0];
3857 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3858 ret = btrfs_next_leaf(rc->extent_root, path);
3859 if (ret != 0)
3860 break;
3861 leaf = path->nodes[0];
3862 }
3863
3864 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3865 if (key.objectid >= last) {
3866 ret = 1;
3867 break;
3868 }
3869
3870 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3871 key.type != BTRFS_METADATA_ITEM_KEY) {
3872 path->slots[0]++;
3873 goto next;
3874 }
3875
3876 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3877 key.objectid + key.offset <= rc->search_start) {
3878 path->slots[0]++;
3879 goto next;
3880 }
3881
3882 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3883 key.objectid + fs_info->nodesize <=
3884 rc->search_start) {
3885 path->slots[0]++;
3886 goto next;
3887 }
3888
3889 ret = find_first_extent_bit(&rc->processed_blocks,
3890 key.objectid, &start, &end,
3891 EXTENT_DIRTY, NULL);
3892
3893 if (ret == 0 && start <= key.objectid) {
3894 btrfs_release_path(path);
3895 rc->search_start = end + 1;
3896 } else {
3897 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3898 rc->search_start = key.objectid + key.offset;
3899 else
3900 rc->search_start = key.objectid +
3901 fs_info->nodesize;
3902 memcpy(extent_key, &key, sizeof(key));
3903 return 0;
3904 }
3905 }
3906 btrfs_release_path(path);
3907 return ret;
3908 }
3909
3910 static void set_reloc_control(struct reloc_control *rc)
3911 {
3912 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3913
3914 mutex_lock(&fs_info->reloc_mutex);
3915 fs_info->reloc_ctl = rc;
3916 mutex_unlock(&fs_info->reloc_mutex);
3917 }
3918
3919 static void unset_reloc_control(struct reloc_control *rc)
3920 {
3921 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3922
3923 mutex_lock(&fs_info->reloc_mutex);
3924 fs_info->reloc_ctl = NULL;
3925 mutex_unlock(&fs_info->reloc_mutex);
3926 }
3927
3928 static int check_extent_flags(u64 flags)
3929 {
3930 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3931 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3932 return 1;
3933 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3934 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3935 return 1;
3936 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3937 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3938 return 1;
3939 return 0;
3940 }
3941
3942 static noinline_for_stack
3943 int prepare_to_relocate(struct reloc_control *rc)
3944 {
3945 struct btrfs_trans_handle *trans;
3946 int ret;
3947
3948 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3949 BTRFS_BLOCK_RSV_TEMP);
3950 if (!rc->block_rsv)
3951 return -ENOMEM;
3952
3953 memset(&rc->cluster, 0, sizeof(rc->cluster));
3954 rc->search_start = rc->block_group->key.objectid;
3955 rc->extents_found = 0;
3956 rc->nodes_relocated = 0;
3957 rc->merging_rsv_size = 0;
3958 rc->reserved_bytes = 0;
3959 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3960 RELOCATION_RESERVED_NODES;
3961 ret = btrfs_block_rsv_refill(rc->extent_root,
3962 rc->block_rsv, rc->block_rsv->size,
3963 BTRFS_RESERVE_FLUSH_ALL);
3964 if (ret)
3965 return ret;
3966
3967 rc->create_reloc_tree = 1;
3968 set_reloc_control(rc);
3969
3970 trans = btrfs_join_transaction(rc->extent_root);
3971 if (IS_ERR(trans)) {
3972 unset_reloc_control(rc);
3973 /*
3974 * extent tree is not a ref_cow tree and has no reloc_root to
3975 * cleanup. And callers are responsible to free the above
3976 * block rsv.
3977 */
3978 return PTR_ERR(trans);
3979 }
3980 btrfs_commit_transaction(trans);
3981 return 0;
3982 }
3983
3984 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3985 {
3986 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3987 struct rb_root blocks = RB_ROOT;
3988 struct btrfs_key key;
3989 struct btrfs_trans_handle *trans = NULL;
3990 struct btrfs_path *path;
3991 struct btrfs_extent_item *ei;
3992 u64 flags;
3993 u32 item_size;
3994 int ret;
3995 int err = 0;
3996 int progress = 0;
3997
3998 path = btrfs_alloc_path();
3999 if (!path)
4000 return -ENOMEM;
4001 path->reada = READA_FORWARD;
4002
4003 ret = prepare_to_relocate(rc);
4004 if (ret) {
4005 err = ret;
4006 goto out_free;
4007 }
4008
4009 while (1) {
4010 rc->reserved_bytes = 0;
4011 ret = btrfs_block_rsv_refill(rc->extent_root,
4012 rc->block_rsv, rc->block_rsv->size,
4013 BTRFS_RESERVE_FLUSH_ALL);
4014 if (ret) {
4015 err = ret;
4016 break;
4017 }
4018 progress++;
4019 trans = btrfs_start_transaction(rc->extent_root, 0);
4020 if (IS_ERR(trans)) {
4021 err = PTR_ERR(trans);
4022 trans = NULL;
4023 break;
4024 }
4025 restart:
4026 if (update_backref_cache(trans, &rc->backref_cache)) {
4027 btrfs_end_transaction(trans);
4028 continue;
4029 }
4030
4031 ret = find_next_extent(rc, path, &key);
4032 if (ret < 0)
4033 err = ret;
4034 if (ret != 0)
4035 break;
4036
4037 rc->extents_found++;
4038
4039 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4040 struct btrfs_extent_item);
4041 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4042 if (item_size >= sizeof(*ei)) {
4043 flags = btrfs_extent_flags(path->nodes[0], ei);
4044 ret = check_extent_flags(flags);
4045 BUG_ON(ret);
4046
4047 } else {
4048 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4049 u64 ref_owner;
4050 int path_change = 0;
4051
4052 BUG_ON(item_size !=
4053 sizeof(struct btrfs_extent_item_v0));
4054 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4055 &path_change);
4056 if (ret < 0) {
4057 err = ret;
4058 break;
4059 }
4060 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4061 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4062 else
4063 flags = BTRFS_EXTENT_FLAG_DATA;
4064
4065 if (path_change) {
4066 btrfs_release_path(path);
4067
4068 path->search_commit_root = 1;
4069 path->skip_locking = 1;
4070 ret = btrfs_search_slot(NULL, rc->extent_root,
4071 &key, path, 0, 0);
4072 if (ret < 0) {
4073 err = ret;
4074 break;
4075 }
4076 BUG_ON(ret > 0);
4077 }
4078 #else
4079 BUG();
4080 #endif
4081 }
4082
4083 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4084 ret = add_tree_block(rc, &key, path, &blocks);
4085 } else if (rc->stage == UPDATE_DATA_PTRS &&
4086 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4087 ret = add_data_references(rc, &key, path, &blocks);
4088 } else {
4089 btrfs_release_path(path);
4090 ret = 0;
4091 }
4092 if (ret < 0) {
4093 err = ret;
4094 break;
4095 }
4096
4097 if (!RB_EMPTY_ROOT(&blocks)) {
4098 ret = relocate_tree_blocks(trans, rc, &blocks);
4099 if (ret < 0) {
4100 /*
4101 * if we fail to relocate tree blocks, force to update
4102 * backref cache when committing transaction.
4103 */
4104 rc->backref_cache.last_trans = trans->transid - 1;
4105
4106 if (ret != -EAGAIN) {
4107 err = ret;
4108 break;
4109 }
4110 rc->extents_found--;
4111 rc->search_start = key.objectid;
4112 }
4113 }
4114
4115 btrfs_end_transaction_throttle(trans);
4116 btrfs_btree_balance_dirty(fs_info);
4117 trans = NULL;
4118
4119 if (rc->stage == MOVE_DATA_EXTENTS &&
4120 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4121 rc->found_file_extent = 1;
4122 ret = relocate_data_extent(rc->data_inode,
4123 &key, &rc->cluster);
4124 if (ret < 0) {
4125 err = ret;
4126 break;
4127 }
4128 }
4129 }
4130 if (trans && progress && err == -ENOSPC) {
4131 ret = btrfs_force_chunk_alloc(trans, fs_info,
4132 rc->block_group->flags);
4133 if (ret == 1) {
4134 err = 0;
4135 progress = 0;
4136 goto restart;
4137 }
4138 }
4139
4140 btrfs_release_path(path);
4141 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4142
4143 if (trans) {
4144 btrfs_end_transaction_throttle(trans);
4145 btrfs_btree_balance_dirty(fs_info);
4146 }
4147
4148 if (!err) {
4149 ret = relocate_file_extent_cluster(rc->data_inode,
4150 &rc->cluster);
4151 if (ret < 0)
4152 err = ret;
4153 }
4154
4155 rc->create_reloc_tree = 0;
4156 set_reloc_control(rc);
4157
4158 backref_cache_cleanup(&rc->backref_cache);
4159 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4160
4161 err = prepare_to_merge(rc, err);
4162
4163 merge_reloc_roots(rc);
4164
4165 rc->merge_reloc_tree = 0;
4166 unset_reloc_control(rc);
4167 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4168
4169 /* get rid of pinned extents */
4170 trans = btrfs_join_transaction(rc->extent_root);
4171 if (IS_ERR(trans)) {
4172 err = PTR_ERR(trans);
4173 goto out_free;
4174 }
4175 btrfs_commit_transaction(trans);
4176 out_free:
4177 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4178 btrfs_free_path(path);
4179 return err;
4180 }
4181
4182 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4183 struct btrfs_root *root, u64 objectid)
4184 {
4185 struct btrfs_path *path;
4186 struct btrfs_inode_item *item;
4187 struct extent_buffer *leaf;
4188 int ret;
4189
4190 path = btrfs_alloc_path();
4191 if (!path)
4192 return -ENOMEM;
4193
4194 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4195 if (ret)
4196 goto out;
4197
4198 leaf = path->nodes[0];
4199 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4200 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4201 btrfs_set_inode_generation(leaf, item, 1);
4202 btrfs_set_inode_size(leaf, item, 0);
4203 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4204 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4205 BTRFS_INODE_PREALLOC);
4206 btrfs_mark_buffer_dirty(leaf);
4207 out:
4208 btrfs_free_path(path);
4209 return ret;
4210 }
4211
4212 /*
4213 * helper to create inode for data relocation.
4214 * the inode is in data relocation tree and its link count is 0
4215 */
4216 static noinline_for_stack
4217 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4218 struct btrfs_block_group_cache *group)
4219 {
4220 struct inode *inode = NULL;
4221 struct btrfs_trans_handle *trans;
4222 struct btrfs_root *root;
4223 struct btrfs_key key;
4224 u64 objectid;
4225 int err = 0;
4226
4227 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4228 if (IS_ERR(root))
4229 return ERR_CAST(root);
4230
4231 trans = btrfs_start_transaction(root, 6);
4232 if (IS_ERR(trans))
4233 return ERR_CAST(trans);
4234
4235 err = btrfs_find_free_objectid(root, &objectid);
4236 if (err)
4237 goto out;
4238
4239 err = __insert_orphan_inode(trans, root, objectid);
4240 BUG_ON(err);
4241
4242 key.objectid = objectid;
4243 key.type = BTRFS_INODE_ITEM_KEY;
4244 key.offset = 0;
4245 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4246 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4247 BTRFS_I(inode)->index_cnt = group->key.objectid;
4248
4249 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4250 out:
4251 btrfs_end_transaction(trans);
4252 btrfs_btree_balance_dirty(fs_info);
4253 if (err) {
4254 if (inode)
4255 iput(inode);
4256 inode = ERR_PTR(err);
4257 }
4258 return inode;
4259 }
4260
4261 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4262 {
4263 struct reloc_control *rc;
4264
4265 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4266 if (!rc)
4267 return NULL;
4268
4269 INIT_LIST_HEAD(&rc->reloc_roots);
4270 backref_cache_init(&rc->backref_cache);
4271 mapping_tree_init(&rc->reloc_root_tree);
4272 extent_io_tree_init(&rc->processed_blocks,
4273 fs_info->btree_inode->i_mapping);
4274 return rc;
4275 }
4276
4277 /*
4278 * Print the block group being relocated
4279 */
4280 static void describe_relocation(struct btrfs_fs_info *fs_info,
4281 struct btrfs_block_group_cache *block_group)
4282 {
4283 char buf[128]; /* prefixed by a '|' that'll be dropped */
4284 u64 flags = block_group->flags;
4285
4286 /* Shouldn't happen */
4287 if (!flags) {
4288 strcpy(buf, "|NONE");
4289 } else {
4290 char *bp = buf;
4291
4292 #define DESCRIBE_FLAG(f, d) \
4293 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4294 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4295 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4296 }
4297 DESCRIBE_FLAG(DATA, "data");
4298 DESCRIBE_FLAG(SYSTEM, "system");
4299 DESCRIBE_FLAG(METADATA, "metadata");
4300 DESCRIBE_FLAG(RAID0, "raid0");
4301 DESCRIBE_FLAG(RAID1, "raid1");
4302 DESCRIBE_FLAG(DUP, "dup");
4303 DESCRIBE_FLAG(RAID10, "raid10");
4304 DESCRIBE_FLAG(RAID5, "raid5");
4305 DESCRIBE_FLAG(RAID6, "raid6");
4306 if (flags)
4307 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4308 #undef DESCRIBE_FLAG
4309 }
4310
4311 btrfs_info(fs_info,
4312 "relocating block group %llu flags %s",
4313 block_group->key.objectid, buf + 1);
4314 }
4315
4316 /*
4317 * function to relocate all extents in a block group.
4318 */
4319 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4320 {
4321 struct btrfs_root *extent_root = fs_info->extent_root;
4322 struct reloc_control *rc;
4323 struct inode *inode;
4324 struct btrfs_path *path;
4325 int ret;
4326 int rw = 0;
4327 int err = 0;
4328
4329 rc = alloc_reloc_control(fs_info);
4330 if (!rc)
4331 return -ENOMEM;
4332
4333 rc->extent_root = extent_root;
4334
4335 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4336 BUG_ON(!rc->block_group);
4337
4338 ret = btrfs_inc_block_group_ro(fs_info, rc->block_group);
4339 if (ret) {
4340 err = ret;
4341 goto out;
4342 }
4343 rw = 1;
4344
4345 path = btrfs_alloc_path();
4346 if (!path) {
4347 err = -ENOMEM;
4348 goto out;
4349 }
4350
4351 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4352 btrfs_free_path(path);
4353
4354 if (!IS_ERR(inode))
4355 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4356 else
4357 ret = PTR_ERR(inode);
4358
4359 if (ret && ret != -ENOENT) {
4360 err = ret;
4361 goto out;
4362 }
4363
4364 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4365 if (IS_ERR(rc->data_inode)) {
4366 err = PTR_ERR(rc->data_inode);
4367 rc->data_inode = NULL;
4368 goto out;
4369 }
4370
4371 describe_relocation(fs_info, rc->block_group);
4372
4373 btrfs_wait_block_group_reservations(rc->block_group);
4374 btrfs_wait_nocow_writers(rc->block_group);
4375 btrfs_wait_ordered_roots(fs_info, -1,
4376 rc->block_group->key.objectid,
4377 rc->block_group->key.offset);
4378
4379 while (1) {
4380 mutex_lock(&fs_info->cleaner_mutex);
4381 ret = relocate_block_group(rc);
4382 mutex_unlock(&fs_info->cleaner_mutex);
4383 if (ret < 0) {
4384 err = ret;
4385 goto out;
4386 }
4387
4388 if (rc->extents_found == 0)
4389 break;
4390
4391 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4392
4393 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4394 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4395 (u64)-1);
4396 if (ret) {
4397 err = ret;
4398 goto out;
4399 }
4400 invalidate_mapping_pages(rc->data_inode->i_mapping,
4401 0, -1);
4402 rc->stage = UPDATE_DATA_PTRS;
4403 }
4404 }
4405
4406 WARN_ON(rc->block_group->pinned > 0);
4407 WARN_ON(rc->block_group->reserved > 0);
4408 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4409 out:
4410 if (err && rw)
4411 btrfs_dec_block_group_ro(rc->block_group);
4412 iput(rc->data_inode);
4413 btrfs_put_block_group(rc->block_group);
4414 kfree(rc);
4415 return err;
4416 }
4417
4418 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4419 {
4420 struct btrfs_fs_info *fs_info = root->fs_info;
4421 struct btrfs_trans_handle *trans;
4422 int ret, err;
4423
4424 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4425 if (IS_ERR(trans))
4426 return PTR_ERR(trans);
4427
4428 memset(&root->root_item.drop_progress, 0,
4429 sizeof(root->root_item.drop_progress));
4430 root->root_item.drop_level = 0;
4431 btrfs_set_root_refs(&root->root_item, 0);
4432 ret = btrfs_update_root(trans, fs_info->tree_root,
4433 &root->root_key, &root->root_item);
4434
4435 err = btrfs_end_transaction(trans);
4436 if (err)
4437 return err;
4438 return ret;
4439 }
4440
4441 /*
4442 * recover relocation interrupted by system crash.
4443 *
4444 * this function resumes merging reloc trees with corresponding fs trees.
4445 * this is important for keeping the sharing of tree blocks
4446 */
4447 int btrfs_recover_relocation(struct btrfs_root *root)
4448 {
4449 struct btrfs_fs_info *fs_info = root->fs_info;
4450 LIST_HEAD(reloc_roots);
4451 struct btrfs_key key;
4452 struct btrfs_root *fs_root;
4453 struct btrfs_root *reloc_root;
4454 struct btrfs_path *path;
4455 struct extent_buffer *leaf;
4456 struct reloc_control *rc = NULL;
4457 struct btrfs_trans_handle *trans;
4458 int ret;
4459 int err = 0;
4460
4461 path = btrfs_alloc_path();
4462 if (!path)
4463 return -ENOMEM;
4464 path->reada = READA_BACK;
4465
4466 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4467 key.type = BTRFS_ROOT_ITEM_KEY;
4468 key.offset = (u64)-1;
4469
4470 while (1) {
4471 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4472 path, 0, 0);
4473 if (ret < 0) {
4474 err = ret;
4475 goto out;
4476 }
4477 if (ret > 0) {
4478 if (path->slots[0] == 0)
4479 break;
4480 path->slots[0]--;
4481 }
4482 leaf = path->nodes[0];
4483 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4484 btrfs_release_path(path);
4485
4486 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4487 key.type != BTRFS_ROOT_ITEM_KEY)
4488 break;
4489
4490 reloc_root = btrfs_read_fs_root(root, &key);
4491 if (IS_ERR(reloc_root)) {
4492 err = PTR_ERR(reloc_root);
4493 goto out;
4494 }
4495
4496 list_add(&reloc_root->root_list, &reloc_roots);
4497
4498 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4499 fs_root = read_fs_root(fs_info,
4500 reloc_root->root_key.offset);
4501 if (IS_ERR(fs_root)) {
4502 ret = PTR_ERR(fs_root);
4503 if (ret != -ENOENT) {
4504 err = ret;
4505 goto out;
4506 }
4507 ret = mark_garbage_root(reloc_root);
4508 if (ret < 0) {
4509 err = ret;
4510 goto out;
4511 }
4512 }
4513 }
4514
4515 if (key.offset == 0)
4516 break;
4517
4518 key.offset--;
4519 }
4520 btrfs_release_path(path);
4521
4522 if (list_empty(&reloc_roots))
4523 goto out;
4524
4525 rc = alloc_reloc_control(fs_info);
4526 if (!rc) {
4527 err = -ENOMEM;
4528 goto out;
4529 }
4530
4531 rc->extent_root = fs_info->extent_root;
4532
4533 set_reloc_control(rc);
4534
4535 trans = btrfs_join_transaction(rc->extent_root);
4536 if (IS_ERR(trans)) {
4537 unset_reloc_control(rc);
4538 err = PTR_ERR(trans);
4539 goto out_free;
4540 }
4541
4542 rc->merge_reloc_tree = 1;
4543
4544 while (!list_empty(&reloc_roots)) {
4545 reloc_root = list_entry(reloc_roots.next,
4546 struct btrfs_root, root_list);
4547 list_del(&reloc_root->root_list);
4548
4549 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4550 list_add_tail(&reloc_root->root_list,
4551 &rc->reloc_roots);
4552 continue;
4553 }
4554
4555 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4556 if (IS_ERR(fs_root)) {
4557 err = PTR_ERR(fs_root);
4558 goto out_free;
4559 }
4560
4561 err = __add_reloc_root(reloc_root);
4562 BUG_ON(err < 0); /* -ENOMEM or logic error */
4563 fs_root->reloc_root = reloc_root;
4564 }
4565
4566 err = btrfs_commit_transaction(trans);
4567 if (err)
4568 goto out_free;
4569
4570 merge_reloc_roots(rc);
4571
4572 unset_reloc_control(rc);
4573
4574 trans = btrfs_join_transaction(rc->extent_root);
4575 if (IS_ERR(trans)) {
4576 err = PTR_ERR(trans);
4577 goto out_free;
4578 }
4579 err = btrfs_commit_transaction(trans);
4580 out_free:
4581 kfree(rc);
4582 out:
4583 if (!list_empty(&reloc_roots))
4584 free_reloc_roots(&reloc_roots);
4585
4586 btrfs_free_path(path);
4587
4588 if (err == 0) {
4589 /* cleanup orphan inode in data relocation tree */
4590 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4591 if (IS_ERR(fs_root))
4592 err = PTR_ERR(fs_root);
4593 else
4594 err = btrfs_orphan_cleanup(fs_root);
4595 }
4596 return err;
4597 }
4598
4599 /*
4600 * helper to add ordered checksum for data relocation.
4601 *
4602 * cloning checksum properly handles the nodatasum extents.
4603 * it also saves CPU time to re-calculate the checksum.
4604 */
4605 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4606 {
4607 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4608 struct btrfs_ordered_sum *sums;
4609 struct btrfs_ordered_extent *ordered;
4610 int ret;
4611 u64 disk_bytenr;
4612 u64 new_bytenr;
4613 LIST_HEAD(list);
4614
4615 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4616 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4617
4618 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4619 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4620 disk_bytenr + len - 1, &list, 0);
4621 if (ret)
4622 goto out;
4623
4624 while (!list_empty(&list)) {
4625 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4626 list_del_init(&sums->list);
4627
4628 /*
4629 * We need to offset the new_bytenr based on where the csum is.
4630 * We need to do this because we will read in entire prealloc
4631 * extents but we may have written to say the middle of the
4632 * prealloc extent, so we need to make sure the csum goes with
4633 * the right disk offset.
4634 *
4635 * We can do this because the data reloc inode refers strictly
4636 * to the on disk bytes, so we don't have to worry about
4637 * disk_len vs real len like with real inodes since it's all
4638 * disk length.
4639 */
4640 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4641 sums->bytenr = new_bytenr;
4642
4643 btrfs_add_ordered_sum(inode, ordered, sums);
4644 }
4645 out:
4646 btrfs_put_ordered_extent(ordered);
4647 return ret;
4648 }
4649
4650 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4651 struct btrfs_root *root, struct extent_buffer *buf,
4652 struct extent_buffer *cow)
4653 {
4654 struct btrfs_fs_info *fs_info = root->fs_info;
4655 struct reloc_control *rc;
4656 struct backref_node *node;
4657 int first_cow = 0;
4658 int level;
4659 int ret = 0;
4660
4661 rc = fs_info->reloc_ctl;
4662 if (!rc)
4663 return 0;
4664
4665 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4666 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4667
4668 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4669 if (buf == root->node)
4670 __update_reloc_root(root, cow->start);
4671 }
4672
4673 level = btrfs_header_level(buf);
4674 if (btrfs_header_generation(buf) <=
4675 btrfs_root_last_snapshot(&root->root_item))
4676 first_cow = 1;
4677
4678 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4679 rc->create_reloc_tree) {
4680 WARN_ON(!first_cow && level == 0);
4681
4682 node = rc->backref_cache.path[level];
4683 BUG_ON(node->bytenr != buf->start &&
4684 node->new_bytenr != buf->start);
4685
4686 drop_node_buffer(node);
4687 extent_buffer_get(cow);
4688 node->eb = cow;
4689 node->new_bytenr = cow->start;
4690
4691 if (!node->pending) {
4692 list_move_tail(&node->list,
4693 &rc->backref_cache.pending[level]);
4694 node->pending = 1;
4695 }
4696
4697 if (first_cow)
4698 __mark_block_processed(rc, node);
4699
4700 if (first_cow && level > 0)
4701 rc->nodes_relocated += buf->len;
4702 }
4703
4704 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4705 ret = replace_file_extents(trans, rc, root, cow);
4706 return ret;
4707 }
4708
4709 /*
4710 * called before creating snapshot. it calculates metadata reservation
4711 * required for relocating tree blocks in the snapshot
4712 */
4713 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4714 u64 *bytes_to_reserve)
4715 {
4716 struct btrfs_root *root;
4717 struct reloc_control *rc;
4718
4719 root = pending->root;
4720 if (!root->reloc_root)
4721 return;
4722
4723 rc = root->fs_info->reloc_ctl;
4724 if (!rc->merge_reloc_tree)
4725 return;
4726
4727 root = root->reloc_root;
4728 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4729 /*
4730 * relocation is in the stage of merging trees. the space
4731 * used by merging a reloc tree is twice the size of
4732 * relocated tree nodes in the worst case. half for cowing
4733 * the reloc tree, half for cowing the fs tree. the space
4734 * used by cowing the reloc tree will be freed after the
4735 * tree is dropped. if we create snapshot, cowing the fs
4736 * tree may use more space than it frees. so we need
4737 * reserve extra space.
4738 */
4739 *bytes_to_reserve += rc->nodes_relocated;
4740 }
4741
4742 /*
4743 * called after snapshot is created. migrate block reservation
4744 * and create reloc root for the newly created snapshot
4745 */
4746 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4747 struct btrfs_pending_snapshot *pending)
4748 {
4749 struct btrfs_root *root = pending->root;
4750 struct btrfs_root *reloc_root;
4751 struct btrfs_root *new_root;
4752 struct reloc_control *rc;
4753 int ret;
4754
4755 if (!root->reloc_root)
4756 return 0;
4757
4758 rc = root->fs_info->reloc_ctl;
4759 rc->merging_rsv_size += rc->nodes_relocated;
4760
4761 if (rc->merge_reloc_tree) {
4762 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4763 rc->block_rsv,
4764 rc->nodes_relocated, 1);
4765 if (ret)
4766 return ret;
4767 }
4768
4769 new_root = pending->snap;
4770 reloc_root = create_reloc_root(trans, root->reloc_root,
4771 new_root->root_key.objectid);
4772 if (IS_ERR(reloc_root))
4773 return PTR_ERR(reloc_root);
4774
4775 ret = __add_reloc_root(reloc_root);
4776 BUG_ON(ret < 0);
4777 new_root->reloc_root = reloc_root;
4778
4779 if (rc->create_reloc_tree)
4780 ret = clone_backref_node(trans, rc, root, reloc_root);
4781 return ret;
4782 }
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