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Btrfs: fix xattr loss after power failure
[linux/fpc-iii.git] / fs / btrfs / relocation.c
blobb041b945a7ae81d8d49272871f8c0009d3ea4ae2
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6 #include <linux/sched.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>
9 #include <linux/blkdev.h>
10 #include <linux/rbtree.h>
11 #include <linux/slab.h>
12 #include "ctree.h"
13 #include "disk-io.h"
14 #include "transaction.h"
15 #include "volumes.h"
16 #include "locking.h"
17 #include "btrfs_inode.h"
18 #include "async-thread.h"
19 #include "free-space-cache.h"
20 #include "inode-map.h"
21 #include "qgroup.h"
22 #include "print-tree.h"
23
24 /*
25 * backref_node, mapping_node and tree_block start with this
26 */
27 struct tree_entry {
28 struct rb_node rb_node;
29 u64 bytenr;
30 };
31
32 /*
33 * present a tree block in the backref cache
34 */
35 struct backref_node {
36 struct rb_node rb_node;
37 u64 bytenr;
38
39 u64 new_bytenr;
40 /* objectid of tree block owner, can be not uptodate */
41 u64 owner;
42 /* link to pending, changed or detached list */
43 struct list_head list;
44 /* list of upper level blocks reference this block */
45 struct list_head upper;
46 /* list of child blocks in the cache */
47 struct list_head lower;
48 /* NULL if this node is not tree root */
49 struct btrfs_root *root;
50 /* extent buffer got by COW the block */
51 struct extent_buffer *eb;
52 /* level of tree block */
53 unsigned int level:8;
54 /* is the block in non-reference counted tree */
55 unsigned int cowonly:1;
56 /* 1 if no child node in the cache */
57 unsigned int lowest:1;
58 /* is the extent buffer locked */
59 unsigned int locked:1;
60 /* has the block been processed */
61 unsigned int processed:1;
62 /* have backrefs of this block been checked */
63 unsigned int checked:1;
64 /*
65 * 1 if corresponding block has been cowed but some upper
66 * level block pointers may not point to the new location
67 */
68 unsigned int pending:1;
69 /*
70 * 1 if the backref node isn't connected to any other
71 * backref node.
72 */
73 unsigned int detached:1;
74 };
75
76 /*
77 * present a block pointer in the backref cache
78 */
79 struct backref_edge {
80 struct list_head list[2];
81 struct backref_node *node[2];
82 };
83
84 #define LOWER 0
85 #define UPPER 1
86 #define RELOCATION_RESERVED_NODES 256
87
88 struct backref_cache {
89 /* red black tree of all backref nodes in the cache */
90 struct rb_root rb_root;
91 /* for passing backref nodes to btrfs_reloc_cow_block */
92 struct backref_node *path[BTRFS_MAX_LEVEL];
93 /*
94 * list of blocks that have been cowed but some block
95 * pointers in upper level blocks may not reflect the
96 * new location
97 */
98 struct list_head pending[BTRFS_MAX_LEVEL];
99 /* list of backref nodes with no child node */
100 struct list_head leaves;
101 /* list of blocks that have been cowed in current transaction */
102 struct list_head changed;
103 /* list of detached backref node. */
104 struct list_head detached;
105
106 u64 last_trans;
107
108 int nr_nodes;
109 int nr_edges;
110 };
111
112 /*
113 * map address of tree root to tree
114 */
115 struct mapping_node {
116 struct rb_node rb_node;
117 u64 bytenr;
118 void *data;
119 };
120
121 struct mapping_tree {
122 struct rb_root rb_root;
123 spinlock_t lock;
124 };
125
126 /*
127 * present a tree block to process
128 */
129 struct tree_block {
130 struct rb_node rb_node;
131 u64 bytenr;
132 struct btrfs_key key;
133 unsigned int level:8;
134 unsigned int key_ready:1;
135 };
136
137 #define MAX_EXTENTS 128
138
139 struct file_extent_cluster {
140 u64 start;
141 u64 end;
142 u64 boundary[MAX_EXTENTS];
143 unsigned int nr;
144 };
145
146 struct reloc_control {
147 /* block group to relocate */
148 struct btrfs_block_group_cache *block_group;
149 /* extent tree */
150 struct btrfs_root *extent_root;
151 /* inode for moving data */
152 struct inode *data_inode;
153
154 struct btrfs_block_rsv *block_rsv;
155
156 struct backref_cache backref_cache;
157
158 struct file_extent_cluster cluster;
159 /* tree blocks have been processed */
160 struct extent_io_tree processed_blocks;
161 /* map start of tree root to corresponding reloc tree */
162 struct mapping_tree reloc_root_tree;
163 /* list of reloc trees */
164 struct list_head reloc_roots;
165 /* size of metadata reservation for merging reloc trees */
166 u64 merging_rsv_size;
167 /* size of relocated tree nodes */
168 u64 nodes_relocated;
169 /* reserved size for block group relocation*/
170 u64 reserved_bytes;
171
172 u64 search_start;
173 u64 extents_found;
174
175 unsigned int stage:8;
176 unsigned int create_reloc_tree:1;
177 unsigned int merge_reloc_tree:1;
178 unsigned int found_file_extent:1;
179 };
180
181 /* stages of data relocation */
182 #define MOVE_DATA_EXTENTS 0
183 #define UPDATE_DATA_PTRS 1
184
185 static void remove_backref_node(struct backref_cache *cache,
186 struct backref_node *node);
187 static void __mark_block_processed(struct reloc_control *rc,
188 struct backref_node *node);
189
190 static void mapping_tree_init(struct mapping_tree *tree)
191 {
192 tree->rb_root = RB_ROOT;
193 spin_lock_init(&tree->lock);
194 }
195
196 static void backref_cache_init(struct backref_cache *cache)
197 {
198 int i;
199 cache->rb_root = RB_ROOT;
200 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
201 INIT_LIST_HEAD(&cache->pending[i]);
202 INIT_LIST_HEAD(&cache->changed);
203 INIT_LIST_HEAD(&cache->detached);
204 INIT_LIST_HEAD(&cache->leaves);
205 }
206
207 static void backref_cache_cleanup(struct backref_cache *cache)
208 {
209 struct backref_node *node;
210 int i;
211
212 while (!list_empty(&cache->detached)) {
213 node = list_entry(cache->detached.next,
214 struct backref_node, list);
215 remove_backref_node(cache, node);
216 }
217
218 while (!list_empty(&cache->leaves)) {
219 node = list_entry(cache->leaves.next,
220 struct backref_node, lower);
221 remove_backref_node(cache, node);
222 }
223
224 cache->last_trans = 0;
225
226 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
227 ASSERT(list_empty(&cache->pending[i]));
228 ASSERT(list_empty(&cache->changed));
229 ASSERT(list_empty(&cache->detached));
230 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
231 ASSERT(!cache->nr_nodes);
232 ASSERT(!cache->nr_edges);
233 }
234
235 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
236 {
237 struct backref_node *node;
238
239 node = kzalloc(sizeof(*node), GFP_NOFS);
240 if (node) {
241 INIT_LIST_HEAD(&node->list);
242 INIT_LIST_HEAD(&node->upper);
243 INIT_LIST_HEAD(&node->lower);
244 RB_CLEAR_NODE(&node->rb_node);
245 cache->nr_nodes++;
246 }
247 return node;
248 }
249
250 static void free_backref_node(struct backref_cache *cache,
251 struct backref_node *node)
252 {
253 if (node) {
254 cache->nr_nodes--;
255 kfree(node);
256 }
257 }
258
259 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
260 {
261 struct backref_edge *edge;
262
263 edge = kzalloc(sizeof(*edge), GFP_NOFS);
264 if (edge)
265 cache->nr_edges++;
266 return edge;
267 }
268
269 static void free_backref_edge(struct backref_cache *cache,
270 struct backref_edge *edge)
271 {
272 if (edge) {
273 cache->nr_edges--;
274 kfree(edge);
275 }
276 }
277
278 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
279 struct rb_node *node)
280 {
281 struct rb_node **p = &root->rb_node;
282 struct rb_node *parent = NULL;
283 struct tree_entry *entry;
284
285 while (*p) {
286 parent = *p;
287 entry = rb_entry(parent, struct tree_entry, rb_node);
288
289 if (bytenr < entry->bytenr)
290 p = &(*p)->rb_left;
291 else if (bytenr > entry->bytenr)
292 p = &(*p)->rb_right;
293 else
294 return parent;
295 }
296
297 rb_link_node(node, parent, p);
298 rb_insert_color(node, root);
299 return NULL;
300 }
301
302 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
303 {
304 struct rb_node *n = root->rb_node;
305 struct tree_entry *entry;
306
307 while (n) {
308 entry = rb_entry(n, struct tree_entry, rb_node);
309
310 if (bytenr < entry->bytenr)
311 n = n->rb_left;
312 else if (bytenr > entry->bytenr)
313 n = n->rb_right;
314 else
315 return n;
316 }
317 return NULL;
318 }
319
320 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
321 {
322
323 struct btrfs_fs_info *fs_info = NULL;
324 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
325 rb_node);
326 if (bnode->root)
327 fs_info = bnode->root->fs_info;
328 btrfs_panic(fs_info, errno,
329 "Inconsistency in backref cache found at offset %llu",
330 bytenr);
331 }
332
333 /*
334 * walk up backref nodes until reach node presents tree root
335 */
336 static struct backref_node *walk_up_backref(struct backref_node *node,
337 struct backref_edge *edges[],
338 int *index)
339 {
340 struct backref_edge *edge;
341 int idx = *index;
342
343 while (!list_empty(&node->upper)) {
344 edge = list_entry(node->upper.next,
345 struct backref_edge, list[LOWER]);
346 edges[idx++] = edge;
347 node = edge->node[UPPER];
348 }
349 BUG_ON(node->detached);
350 *index = idx;
351 return node;
352 }
353
354 /*
355 * walk down backref nodes to find start of next reference path
356 */
357 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
358 int *index)
359 {
360 struct backref_edge *edge;
361 struct backref_node *lower;
362 int idx = *index;
363
364 while (idx > 0) {
365 edge = edges[idx - 1];
366 lower = edge->node[LOWER];
367 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
368 idx--;
369 continue;
370 }
371 edge = list_entry(edge->list[LOWER].next,
372 struct backref_edge, list[LOWER]);
373 edges[idx - 1] = edge;
374 *index = idx;
375 return edge->node[UPPER];
376 }
377 *index = 0;
378 return NULL;
379 }
380
381 static void unlock_node_buffer(struct backref_node *node)
382 {
383 if (node->locked) {
384 btrfs_tree_unlock(node->eb);
385 node->locked = 0;
386 }
387 }
388
389 static void drop_node_buffer(struct backref_node *node)
390 {
391 if (node->eb) {
392 unlock_node_buffer(node);
393 free_extent_buffer(node->eb);
394 node->eb = NULL;
395 }
396 }
397
398 static void drop_backref_node(struct backref_cache *tree,
399 struct backref_node *node)
400 {
401 BUG_ON(!list_empty(&node->upper));
402
403 drop_node_buffer(node);
404 list_del(&node->list);
405 list_del(&node->lower);
406 if (!RB_EMPTY_NODE(&node->rb_node))
407 rb_erase(&node->rb_node, &tree->rb_root);
408 free_backref_node(tree, node);
409 }
410
411 /*
412 * remove a backref node from the backref cache
413 */
414 static void remove_backref_node(struct backref_cache *cache,
415 struct backref_node *node)
416 {
417 struct backref_node *upper;
418 struct backref_edge *edge;
419
420 if (!node)
421 return;
422
423 BUG_ON(!node->lowest && !node->detached);
424 while (!list_empty(&node->upper)) {
425 edge = list_entry(node->upper.next, struct backref_edge,
426 list[LOWER]);
427 upper = edge->node[UPPER];
428 list_del(&edge->list[LOWER]);
429 list_del(&edge->list[UPPER]);
430 free_backref_edge(cache, edge);
431
432 if (RB_EMPTY_NODE(&upper->rb_node)) {
433 BUG_ON(!list_empty(&node->upper));
434 drop_backref_node(cache, node);
435 node = upper;
436 node->lowest = 1;
437 continue;
438 }
439 /*
440 * add the node to leaf node list if no other
441 * child block cached.
442 */
443 if (list_empty(&upper->lower)) {
444 list_add_tail(&upper->lower, &cache->leaves);
445 upper->lowest = 1;
446 }
447 }
448
449 drop_backref_node(cache, node);
450 }
451
452 static void update_backref_node(struct backref_cache *cache,
453 struct backref_node *node, u64 bytenr)
454 {
455 struct rb_node *rb_node;
456 rb_erase(&node->rb_node, &cache->rb_root);
457 node->bytenr = bytenr;
458 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
459 if (rb_node)
460 backref_tree_panic(rb_node, -EEXIST, bytenr);
461 }
462
463 /*
464 * update backref cache after a transaction commit
465 */
466 static int update_backref_cache(struct btrfs_trans_handle *trans,
467 struct backref_cache *cache)
468 {
469 struct backref_node *node;
470 int level = 0;
471
472 if (cache->last_trans == 0) {
473 cache->last_trans = trans->transid;
474 return 0;
475 }
476
477 if (cache->last_trans == trans->transid)
478 return 0;
479
480 /*
481 * detached nodes are used to avoid unnecessary backref
482 * lookup. transaction commit changes the extent tree.
483 * so the detached nodes are no longer useful.
484 */
485 while (!list_empty(&cache->detached)) {
486 node = list_entry(cache->detached.next,
487 struct backref_node, list);
488 remove_backref_node(cache, node);
489 }
490
491 while (!list_empty(&cache->changed)) {
492 node = list_entry(cache->changed.next,
493 struct backref_node, list);
494 list_del_init(&node->list);
495 BUG_ON(node->pending);
496 update_backref_node(cache, node, node->new_bytenr);
497 }
498
499 /*
500 * some nodes can be left in the pending list if there were
501 * errors during processing the pending nodes.
502 */
503 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
504 list_for_each_entry(node, &cache->pending[level], list) {
505 BUG_ON(!node->pending);
506 if (node->bytenr == node->new_bytenr)
507 continue;
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510 }
511
512 cache->last_trans = 0;
513 return 1;
514 }
515
516
517 static int should_ignore_root(struct btrfs_root *root)
518 {
519 struct btrfs_root *reloc_root;
520
521 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
522 return 0;
523
524 reloc_root = root->reloc_root;
525 if (!reloc_root)
526 return 0;
527
528 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
529 root->fs_info->running_transaction->transid - 1)
530 return 0;
531 /*
532 * if there is reloc tree and it was created in previous
533 * transaction backref lookup can find the reloc tree,
534 * so backref node for the fs tree root is useless for
535 * relocation.
536 */
537 return 1;
538 }
539 /*
540 * find reloc tree by address of tree root
541 */
542 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
543 u64 bytenr)
544 {
545 struct rb_node *rb_node;
546 struct mapping_node *node;
547 struct btrfs_root *root = NULL;
548
549 spin_lock(&rc->reloc_root_tree.lock);
550 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
551 if (rb_node) {
552 node = rb_entry(rb_node, struct mapping_node, rb_node);
553 root = (struct btrfs_root *)node->data;
554 }
555 spin_unlock(&rc->reloc_root_tree.lock);
556 return root;
557 }
558
559 static int is_cowonly_root(u64 root_objectid)
560 {
561 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
562 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
563 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
564 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
565 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
566 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
567 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
568 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
569 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
570 return 1;
571 return 0;
572 }
573
574 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
575 u64 root_objectid)
576 {
577 struct btrfs_key key;
578
579 key.objectid = root_objectid;
580 key.type = BTRFS_ROOT_ITEM_KEY;
581 if (is_cowonly_root(root_objectid))
582 key.offset = 0;
583 else
584 key.offset = (u64)-1;
585
586 return btrfs_get_fs_root(fs_info, &key, false);
587 }
588
589 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
590 static noinline_for_stack
591 struct btrfs_root *find_tree_root(struct reloc_control *rc,
592 struct extent_buffer *leaf,
593 struct btrfs_extent_ref_v0 *ref0)
594 {
595 struct btrfs_root *root;
596 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
597 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
598
599 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
600
601 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
602 BUG_ON(IS_ERR(root));
603
604 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
605 generation != btrfs_root_generation(&root->root_item))
606 return NULL;
607
608 return root;
609 }
610 #endif
611
612 static noinline_for_stack
613 int find_inline_backref(struct extent_buffer *leaf, int slot,
614 unsigned long *ptr, unsigned long *end)
615 {
616 struct btrfs_key key;
617 struct btrfs_extent_item *ei;
618 struct btrfs_tree_block_info *bi;
619 u32 item_size;
620
621 btrfs_item_key_to_cpu(leaf, &key, slot);
622
623 item_size = btrfs_item_size_nr(leaf, slot);
624 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
625 if (item_size < sizeof(*ei)) {
626 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
627 return 1;
628 }
629 #endif
630 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
631 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
632 BTRFS_EXTENT_FLAG_TREE_BLOCK));
633
634 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
635 item_size <= sizeof(*ei) + sizeof(*bi)) {
636 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
637 return 1;
638 }
639 if (key.type == BTRFS_METADATA_ITEM_KEY &&
640 item_size <= sizeof(*ei)) {
641 WARN_ON(item_size < sizeof(*ei));
642 return 1;
643 }
644
645 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
646 bi = (struct btrfs_tree_block_info *)(ei + 1);
647 *ptr = (unsigned long)(bi + 1);
648 } else {
649 *ptr = (unsigned long)(ei + 1);
650 }
651 *end = (unsigned long)ei + item_size;
652 return 0;
653 }
654
655 /*
656 * build backref tree for a given tree block. root of the backref tree
657 * corresponds the tree block, leaves of the backref tree correspond
658 * roots of b-trees that reference the tree block.
659 *
660 * the basic idea of this function is check backrefs of a given block
661 * to find upper level blocks that reference the block, and then check
662 * backrefs of these upper level blocks recursively. the recursion stop
663 * when tree root is reached or backrefs for the block is cached.
664 *
665 * NOTE: if we find backrefs for a block are cached, we know backrefs
666 * for all upper level blocks that directly/indirectly reference the
667 * block are also cached.
668 */
669 static noinline_for_stack
670 struct backref_node *build_backref_tree(struct reloc_control *rc,
671 struct btrfs_key *node_key,
672 int level, u64 bytenr)
673 {
674 struct backref_cache *cache = &rc->backref_cache;
675 struct btrfs_path *path1;
676 struct btrfs_path *path2;
677 struct extent_buffer *eb;
678 struct btrfs_root *root;
679 struct backref_node *cur;
680 struct backref_node *upper;
681 struct backref_node *lower;
682 struct backref_node *node = NULL;
683 struct backref_node *exist = NULL;
684 struct backref_edge *edge;
685 struct rb_node *rb_node;
686 struct btrfs_key key;
687 unsigned long end;
688 unsigned long ptr;
689 LIST_HEAD(list);
690 LIST_HEAD(useless);
691 int cowonly;
692 int ret;
693 int err = 0;
694 bool need_check = true;
695
696 path1 = btrfs_alloc_path();
697 path2 = btrfs_alloc_path();
698 if (!path1 || !path2) {
699 err = -ENOMEM;
700 goto out;
701 }
702 path1->reada = READA_FORWARD;
703 path2->reada = READA_FORWARD;
704
705 node = alloc_backref_node(cache);
706 if (!node) {
707 err = -ENOMEM;
708 goto out;
709 }
710
711 node->bytenr = bytenr;
712 node->level = level;
713 node->lowest = 1;
714 cur = node;
715 again:
716 end = 0;
717 ptr = 0;
718 key.objectid = cur->bytenr;
719 key.type = BTRFS_METADATA_ITEM_KEY;
720 key.offset = (u64)-1;
721
722 path1->search_commit_root = 1;
723 path1->skip_locking = 1;
724 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
725 0, 0);
726 if (ret < 0) {
727 err = ret;
728 goto out;
729 }
730 ASSERT(ret);
731 ASSERT(path1->slots[0]);
732
733 path1->slots[0]--;
734
735 WARN_ON(cur->checked);
736 if (!list_empty(&cur->upper)) {
737 /*
738 * the backref was added previously when processing
739 * backref of type BTRFS_TREE_BLOCK_REF_KEY
740 */
741 ASSERT(list_is_singular(&cur->upper));
742 edge = list_entry(cur->upper.next, struct backref_edge,
743 list[LOWER]);
744 ASSERT(list_empty(&edge->list[UPPER]));
745 exist = edge->node[UPPER];
746 /*
747 * add the upper level block to pending list if we need
748 * check its backrefs
749 */
750 if (!exist->checked)
751 list_add_tail(&edge->list[UPPER], &list);
752 } else {
753 exist = NULL;
754 }
755
756 while (1) {
757 cond_resched();
758 eb = path1->nodes[0];
759
760 if (ptr >= end) {
761 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
762 ret = btrfs_next_leaf(rc->extent_root, path1);
763 if (ret < 0) {
764 err = ret;
765 goto out;
766 }
767 if (ret > 0)
768 break;
769 eb = path1->nodes[0];
770 }
771
772 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
773 if (key.objectid != cur->bytenr) {
774 WARN_ON(exist);
775 break;
776 }
777
778 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
779 key.type == BTRFS_METADATA_ITEM_KEY) {
780 ret = find_inline_backref(eb, path1->slots[0],
781 &ptr, &end);
782 if (ret)
783 goto next;
784 }
785 }
786
787 if (ptr < end) {
788 /* update key for inline back ref */
789 struct btrfs_extent_inline_ref *iref;
790 int type;
791 iref = (struct btrfs_extent_inline_ref *)ptr;
792 type = btrfs_get_extent_inline_ref_type(eb, iref,
793 BTRFS_REF_TYPE_BLOCK);
794 if (type == BTRFS_REF_TYPE_INVALID) {
795 err = -EINVAL;
796 goto out;
797 }
798 key.type = type;
799 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
800
801 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
802 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
803 }
804
805 if (exist &&
806 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
807 exist->owner == key.offset) ||
808 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
809 exist->bytenr == key.offset))) {
810 exist = NULL;
811 goto next;
812 }
813
814 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
815 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
816 key.type == BTRFS_EXTENT_REF_V0_KEY) {
817 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
818 struct btrfs_extent_ref_v0 *ref0;
819 ref0 = btrfs_item_ptr(eb, path1->slots[0],
820 struct btrfs_extent_ref_v0);
821 if (key.objectid == key.offset) {
822 root = find_tree_root(rc, eb, ref0);
823 if (root && !should_ignore_root(root))
824 cur->root = root;
825 else
826 list_add(&cur->list, &useless);
827 break;
828 }
829 if (is_cowonly_root(btrfs_ref_root_v0(eb,
830 ref0)))
831 cur->cowonly = 1;
832 }
833 #else
834 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
835 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
836 #endif
837 if (key.objectid == key.offset) {
838 /*
839 * only root blocks of reloc trees use
840 * backref of this type.
841 */
842 root = find_reloc_root(rc, cur->bytenr);
843 ASSERT(root);
844 cur->root = root;
845 break;
846 }
847
848 edge = alloc_backref_edge(cache);
849 if (!edge) {
850 err = -ENOMEM;
851 goto out;
852 }
853 rb_node = tree_search(&cache->rb_root, key.offset);
854 if (!rb_node) {
855 upper = alloc_backref_node(cache);
856 if (!upper) {
857 free_backref_edge(cache, edge);
858 err = -ENOMEM;
859 goto out;
860 }
861 upper->bytenr = key.offset;
862 upper->level = cur->level + 1;
863 /*
864 * backrefs for the upper level block isn't
865 * cached, add the block to pending list
866 */
867 list_add_tail(&edge->list[UPPER], &list);
868 } else {
869 upper = rb_entry(rb_node, struct backref_node,
870 rb_node);
871 ASSERT(upper->checked);
872 INIT_LIST_HEAD(&edge->list[UPPER]);
873 }
874 list_add_tail(&edge->list[LOWER], &cur->upper);
875 edge->node[LOWER] = cur;
876 edge->node[UPPER] = upper;
877
878 goto next;
879 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
880 goto next;
881 }
882
883 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
884 root = read_fs_root(rc->extent_root->fs_info, key.offset);
885 if (IS_ERR(root)) {
886 err = PTR_ERR(root);
887 goto out;
888 }
889
890 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
891 cur->cowonly = 1;
892
893 if (btrfs_root_level(&root->root_item) == cur->level) {
894 /* tree root */
895 ASSERT(btrfs_root_bytenr(&root->root_item) ==
896 cur->bytenr);
897 if (should_ignore_root(root))
898 list_add(&cur->list, &useless);
899 else
900 cur->root = root;
901 break;
902 }
903
904 level = cur->level + 1;
905
906 /*
907 * searching the tree to find upper level blocks
908 * reference the block.
909 */
910 path2->search_commit_root = 1;
911 path2->skip_locking = 1;
912 path2->lowest_level = level;
913 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
914 path2->lowest_level = 0;
915 if (ret < 0) {
916 err = ret;
917 goto out;
918 }
919 if (ret > 0 && path2->slots[level] > 0)
920 path2->slots[level]--;
921
922 eb = path2->nodes[level];
923 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
924 cur->bytenr) {
925 btrfs_err(root->fs_info,
926 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
927 cur->bytenr, level - 1, root->objectid,
928 node_key->objectid, node_key->type,
929 node_key->offset);
930 err = -ENOENT;
931 goto out;
932 }
933 lower = cur;
934 need_check = true;
935 for (; level < BTRFS_MAX_LEVEL; level++) {
936 if (!path2->nodes[level]) {
937 ASSERT(btrfs_root_bytenr(&root->root_item) ==
938 lower->bytenr);
939 if (should_ignore_root(root))
940 list_add(&lower->list, &useless);
941 else
942 lower->root = root;
943 break;
944 }
945
946 edge = alloc_backref_edge(cache);
947 if (!edge) {
948 err = -ENOMEM;
949 goto out;
950 }
951
952 eb = path2->nodes[level];
953 rb_node = tree_search(&cache->rb_root, eb->start);
954 if (!rb_node) {
955 upper = alloc_backref_node(cache);
956 if (!upper) {
957 free_backref_edge(cache, edge);
958 err = -ENOMEM;
959 goto out;
960 }
961 upper->bytenr = eb->start;
962 upper->owner = btrfs_header_owner(eb);
963 upper->level = lower->level + 1;
964 if (!test_bit(BTRFS_ROOT_REF_COWS,
965 &root->state))
966 upper->cowonly = 1;
967
968 /*
969 * if we know the block isn't shared
970 * we can void checking its backrefs.
971 */
972 if (btrfs_block_can_be_shared(root, eb))
973 upper->checked = 0;
974 else
975 upper->checked = 1;
976
977 /*
978 * add the block to pending list if we
979 * need check its backrefs, we only do this once
980 * while walking up a tree as we will catch
981 * anything else later on.
982 */
983 if (!upper->checked && need_check) {
984 need_check = false;
985 list_add_tail(&edge->list[UPPER],
986 &list);
987 } else {
988 if (upper->checked)
989 need_check = true;
990 INIT_LIST_HEAD(&edge->list[UPPER]);
991 }
992 } else {
993 upper = rb_entry(rb_node, struct backref_node,
994 rb_node);
995 ASSERT(upper->checked);
996 INIT_LIST_HEAD(&edge->list[UPPER]);
997 if (!upper->owner)
998 upper->owner = btrfs_header_owner(eb);
999 }
1000 list_add_tail(&edge->list[LOWER], &lower->upper);
1001 edge->node[LOWER] = lower;
1002 edge->node[UPPER] = upper;
1003
1004 if (rb_node)
1005 break;
1006 lower = upper;
1007 upper = NULL;
1008 }
1009 btrfs_release_path(path2);
1010 next:
1011 if (ptr < end) {
1012 ptr += btrfs_extent_inline_ref_size(key.type);
1013 if (ptr >= end) {
1014 WARN_ON(ptr > end);
1015 ptr = 0;
1016 end = 0;
1017 }
1018 }
1019 if (ptr >= end)
1020 path1->slots[0]++;
1021 }
1022 btrfs_release_path(path1);
1023
1024 cur->checked = 1;
1025 WARN_ON(exist);
1026
1027 /* the pending list isn't empty, take the first block to process */
1028 if (!list_empty(&list)) {
1029 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1030 list_del_init(&edge->list[UPPER]);
1031 cur = edge->node[UPPER];
1032 goto again;
1033 }
1034
1035 /*
1036 * everything goes well, connect backref nodes and insert backref nodes
1037 * into the cache.
1038 */
1039 ASSERT(node->checked);
1040 cowonly = node->cowonly;
1041 if (!cowonly) {
1042 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1043 &node->rb_node);
1044 if (rb_node)
1045 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1046 list_add_tail(&node->lower, &cache->leaves);
1047 }
1048
1049 list_for_each_entry(edge, &node->upper, list[LOWER])
1050 list_add_tail(&edge->list[UPPER], &list);
1051
1052 while (!list_empty(&list)) {
1053 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1054 list_del_init(&edge->list[UPPER]);
1055 upper = edge->node[UPPER];
1056 if (upper->detached) {
1057 list_del(&edge->list[LOWER]);
1058 lower = edge->node[LOWER];
1059 free_backref_edge(cache, edge);
1060 if (list_empty(&lower->upper))
1061 list_add(&lower->list, &useless);
1062 continue;
1063 }
1064
1065 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1066 if (upper->lowest) {
1067 list_del_init(&upper->lower);
1068 upper->lowest = 0;
1069 }
1070
1071 list_add_tail(&edge->list[UPPER], &upper->lower);
1072 continue;
1073 }
1074
1075 if (!upper->checked) {
1076 /*
1077 * Still want to blow up for developers since this is a
1078 * logic bug.
1079 */
1080 ASSERT(0);
1081 err = -EINVAL;
1082 goto out;
1083 }
1084 if (cowonly != upper->cowonly) {
1085 ASSERT(0);
1086 err = -EINVAL;
1087 goto out;
1088 }
1089
1090 if (!cowonly) {
1091 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1092 &upper->rb_node);
1093 if (rb_node)
1094 backref_tree_panic(rb_node, -EEXIST,
1095 upper->bytenr);
1096 }
1097
1098 list_add_tail(&edge->list[UPPER], &upper->lower);
1099
1100 list_for_each_entry(edge, &upper->upper, list[LOWER])
1101 list_add_tail(&edge->list[UPPER], &list);
1102 }
1103 /*
1104 * process useless backref nodes. backref nodes for tree leaves
1105 * are deleted from the cache. backref nodes for upper level
1106 * tree blocks are left in the cache to avoid unnecessary backref
1107 * lookup.
1108 */
1109 while (!list_empty(&useless)) {
1110 upper = list_entry(useless.next, struct backref_node, list);
1111 list_del_init(&upper->list);
1112 ASSERT(list_empty(&upper->upper));
1113 if (upper == node)
1114 node = NULL;
1115 if (upper->lowest) {
1116 list_del_init(&upper->lower);
1117 upper->lowest = 0;
1118 }
1119 while (!list_empty(&upper->lower)) {
1120 edge = list_entry(upper->lower.next,
1121 struct backref_edge, list[UPPER]);
1122 list_del(&edge->list[UPPER]);
1123 list_del(&edge->list[LOWER]);
1124 lower = edge->node[LOWER];
1125 free_backref_edge(cache, edge);
1126
1127 if (list_empty(&lower->upper))
1128 list_add(&lower->list, &useless);
1129 }
1130 __mark_block_processed(rc, upper);
1131 if (upper->level > 0) {
1132 list_add(&upper->list, &cache->detached);
1133 upper->detached = 1;
1134 } else {
1135 rb_erase(&upper->rb_node, &cache->rb_root);
1136 free_backref_node(cache, upper);
1137 }
1138 }
1139 out:
1140 btrfs_free_path(path1);
1141 btrfs_free_path(path2);
1142 if (err) {
1143 while (!list_empty(&useless)) {
1144 lower = list_entry(useless.next,
1145 struct backref_node, list);
1146 list_del_init(&lower->list);
1147 }
1148 while (!list_empty(&list)) {
1149 edge = list_first_entry(&list, struct backref_edge,
1150 list[UPPER]);
1151 list_del(&edge->list[UPPER]);
1152 list_del(&edge->list[LOWER]);
1153 lower = edge->node[LOWER];
1154 upper = edge->node[UPPER];
1155 free_backref_edge(cache, edge);
1156
1157 /*
1158 * Lower is no longer linked to any upper backref nodes
1159 * and isn't in the cache, we can free it ourselves.
1160 */
1161 if (list_empty(&lower->upper) &&
1162 RB_EMPTY_NODE(&lower->rb_node))
1163 list_add(&lower->list, &useless);
1164
1165 if (!RB_EMPTY_NODE(&upper->rb_node))
1166 continue;
1167
1168 /* Add this guy's upper edges to the list to process */
1169 list_for_each_entry(edge, &upper->upper, list[LOWER])
1170 list_add_tail(&edge->list[UPPER], &list);
1171 if (list_empty(&upper->upper))
1172 list_add(&upper->list, &useless);
1173 }
1174
1175 while (!list_empty(&useless)) {
1176 lower = list_entry(useless.next,
1177 struct backref_node, list);
1178 list_del_init(&lower->list);
1179 if (lower == node)
1180 node = NULL;
1181 free_backref_node(cache, lower);
1182 }
1183
1184 free_backref_node(cache, node);
1185 return ERR_PTR(err);
1186 }
1187 ASSERT(!node || !node->detached);
1188 return node;
1189 }
1190
1191 /*
1192 * helper to add backref node for the newly created snapshot.
1193 * the backref node is created by cloning backref node that
1194 * corresponds to root of source tree
1195 */
1196 static int clone_backref_node(struct btrfs_trans_handle *trans,
1197 struct reloc_control *rc,
1198 struct btrfs_root *src,
1199 struct btrfs_root *dest)
1200 {
1201 struct btrfs_root *reloc_root = src->reloc_root;
1202 struct backref_cache *cache = &rc->backref_cache;
1203 struct backref_node *node = NULL;
1204 struct backref_node *new_node;
1205 struct backref_edge *edge;
1206 struct backref_edge *new_edge;
1207 struct rb_node *rb_node;
1208
1209 if (cache->last_trans > 0)
1210 update_backref_cache(trans, cache);
1211
1212 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1213 if (rb_node) {
1214 node = rb_entry(rb_node, struct backref_node, rb_node);
1215 if (node->detached)
1216 node = NULL;
1217 else
1218 BUG_ON(node->new_bytenr != reloc_root->node->start);
1219 }
1220
1221 if (!node) {
1222 rb_node = tree_search(&cache->rb_root,
1223 reloc_root->commit_root->start);
1224 if (rb_node) {
1225 node = rb_entry(rb_node, struct backref_node,
1226 rb_node);
1227 BUG_ON(node->detached);
1228 }
1229 }
1230
1231 if (!node)
1232 return 0;
1233
1234 new_node = alloc_backref_node(cache);
1235 if (!new_node)
1236 return -ENOMEM;
1237
1238 new_node->bytenr = dest->node->start;
1239 new_node->level = node->level;
1240 new_node->lowest = node->lowest;
1241 new_node->checked = 1;
1242 new_node->root = dest;
1243
1244 if (!node->lowest) {
1245 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1246 new_edge = alloc_backref_edge(cache);
1247 if (!new_edge)
1248 goto fail;
1249
1250 new_edge->node[UPPER] = new_node;
1251 new_edge->node[LOWER] = edge->node[LOWER];
1252 list_add_tail(&new_edge->list[UPPER],
1253 &new_node->lower);
1254 }
1255 } else {
1256 list_add_tail(&new_node->lower, &cache->leaves);
1257 }
1258
1259 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1260 &new_node->rb_node);
1261 if (rb_node)
1262 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1263
1264 if (!new_node->lowest) {
1265 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1266 list_add_tail(&new_edge->list[LOWER],
1267 &new_edge->node[LOWER]->upper);
1268 }
1269 }
1270 return 0;
1271 fail:
1272 while (!list_empty(&new_node->lower)) {
1273 new_edge = list_entry(new_node->lower.next,
1274 struct backref_edge, list[UPPER]);
1275 list_del(&new_edge->list[UPPER]);
1276 free_backref_edge(cache, new_edge);
1277 }
1278 free_backref_node(cache, new_node);
1279 return -ENOMEM;
1280 }
1281
1282 /*
1283 * helper to add 'address of tree root -> reloc tree' mapping
1284 */
1285 static int __must_check __add_reloc_root(struct btrfs_root *root)
1286 {
1287 struct btrfs_fs_info *fs_info = root->fs_info;
1288 struct rb_node *rb_node;
1289 struct mapping_node *node;
1290 struct reloc_control *rc = fs_info->reloc_ctl;
1291
1292 node = kmalloc(sizeof(*node), GFP_NOFS);
1293 if (!node)
1294 return -ENOMEM;
1295
1296 node->bytenr = root->node->start;
1297 node->data = root;
1298
1299 spin_lock(&rc->reloc_root_tree.lock);
1300 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1301 node->bytenr, &node->rb_node);
1302 spin_unlock(&rc->reloc_root_tree.lock);
1303 if (rb_node) {
1304 btrfs_panic(fs_info, -EEXIST,
1305 "Duplicate root found for start=%llu while inserting into relocation tree",
1306 node->bytenr);
1307 }
1308
1309 list_add_tail(&root->root_list, &rc->reloc_roots);
1310 return 0;
1311 }
1312
1313 /*
1314 * helper to delete the 'address of tree root -> reloc tree'
1315 * mapping
1316 */
1317 static void __del_reloc_root(struct btrfs_root *root)
1318 {
1319 struct btrfs_fs_info *fs_info = root->fs_info;
1320 struct rb_node *rb_node;
1321 struct mapping_node *node = NULL;
1322 struct reloc_control *rc = fs_info->reloc_ctl;
1323
1324 spin_lock(&rc->reloc_root_tree.lock);
1325 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1326 root->node->start);
1327 if (rb_node) {
1328 node = rb_entry(rb_node, struct mapping_node, rb_node);
1329 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1330 }
1331 spin_unlock(&rc->reloc_root_tree.lock);
1332
1333 if (!node)
1334 return;
1335 BUG_ON((struct btrfs_root *)node->data != root);
1336
1337 spin_lock(&fs_info->trans_lock);
1338 list_del_init(&root->root_list);
1339 spin_unlock(&fs_info->trans_lock);
1340 kfree(node);
1341 }
1342
1343 /*
1344 * helper to update the 'address of tree root -> reloc tree'
1345 * mapping
1346 */
1347 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1348 {
1349 struct btrfs_fs_info *fs_info = root->fs_info;
1350 struct rb_node *rb_node;
1351 struct mapping_node *node = NULL;
1352 struct reloc_control *rc = fs_info->reloc_ctl;
1353
1354 spin_lock(&rc->reloc_root_tree.lock);
1355 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1356 root->node->start);
1357 if (rb_node) {
1358 node = rb_entry(rb_node, struct mapping_node, rb_node);
1359 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1360 }
1361 spin_unlock(&rc->reloc_root_tree.lock);
1362
1363 if (!node)
1364 return 0;
1365 BUG_ON((struct btrfs_root *)node->data != root);
1366
1367 spin_lock(&rc->reloc_root_tree.lock);
1368 node->bytenr = new_bytenr;
1369 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1370 node->bytenr, &node->rb_node);
1371 spin_unlock(&rc->reloc_root_tree.lock);
1372 if (rb_node)
1373 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1374 return 0;
1375 }
1376
1377 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1378 struct btrfs_root *root, u64 objectid)
1379 {
1380 struct btrfs_fs_info *fs_info = root->fs_info;
1381 struct btrfs_root *reloc_root;
1382 struct extent_buffer *eb;
1383 struct btrfs_root_item *root_item;
1384 struct btrfs_key root_key;
1385 int ret;
1386
1387 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1388 BUG_ON(!root_item);
1389
1390 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1391 root_key.type = BTRFS_ROOT_ITEM_KEY;
1392 root_key.offset = objectid;
1393
1394 if (root->root_key.objectid == objectid) {
1395 u64 commit_root_gen;
1396
1397 /* called by btrfs_init_reloc_root */
1398 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1399 BTRFS_TREE_RELOC_OBJECTID);
1400 BUG_ON(ret);
1401 /*
1402 * Set the last_snapshot field to the generation of the commit
1403 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1404 * correctly (returns true) when the relocation root is created
1405 * either inside the critical section of a transaction commit
1406 * (through transaction.c:qgroup_account_snapshot()) and when
1407 * it's created before the transaction commit is started.
1408 */
1409 commit_root_gen = btrfs_header_generation(root->commit_root);
1410 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1411 } else {
1412 /*
1413 * called by btrfs_reloc_post_snapshot_hook.
1414 * the source tree is a reloc tree, all tree blocks
1415 * modified after it was created have RELOC flag
1416 * set in their headers. so it's OK to not update
1417 * the 'last_snapshot'.
1418 */
1419 ret = btrfs_copy_root(trans, root, root->node, &eb,
1420 BTRFS_TREE_RELOC_OBJECTID);
1421 BUG_ON(ret);
1422 }
1423
1424 memcpy(root_item, &root->root_item, sizeof(*root_item));
1425 btrfs_set_root_bytenr(root_item, eb->start);
1426 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1427 btrfs_set_root_generation(root_item, trans->transid);
1428
1429 if (root->root_key.objectid == objectid) {
1430 btrfs_set_root_refs(root_item, 0);
1431 memset(&root_item->drop_progress, 0,
1432 sizeof(struct btrfs_disk_key));
1433 root_item->drop_level = 0;
1434 }
1435
1436 btrfs_tree_unlock(eb);
1437 free_extent_buffer(eb);
1438
1439 ret = btrfs_insert_root(trans, fs_info->tree_root,
1440 &root_key, root_item);
1441 BUG_ON(ret);
1442 kfree(root_item);
1443
1444 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1445 BUG_ON(IS_ERR(reloc_root));
1446 reloc_root->last_trans = trans->transid;
1447 return reloc_root;
1448 }
1449
1450 /*
1451 * create reloc tree for a given fs tree. reloc tree is just a
1452 * snapshot of the fs tree with special root objectid.
1453 */
1454 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1455 struct btrfs_root *root)
1456 {
1457 struct btrfs_fs_info *fs_info = root->fs_info;
1458 struct btrfs_root *reloc_root;
1459 struct reloc_control *rc = fs_info->reloc_ctl;
1460 struct btrfs_block_rsv *rsv;
1461 int clear_rsv = 0;
1462 int ret;
1463
1464 if (root->reloc_root) {
1465 reloc_root = root->reloc_root;
1466 reloc_root->last_trans = trans->transid;
1467 return 0;
1468 }
1469
1470 if (!rc || !rc->create_reloc_tree ||
1471 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1472 return 0;
1473
1474 if (!trans->reloc_reserved) {
1475 rsv = trans->block_rsv;
1476 trans->block_rsv = rc->block_rsv;
1477 clear_rsv = 1;
1478 }
1479 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1480 if (clear_rsv)
1481 trans->block_rsv = rsv;
1482
1483 ret = __add_reloc_root(reloc_root);
1484 BUG_ON(ret < 0);
1485 root->reloc_root = reloc_root;
1486 return 0;
1487 }
1488
1489 /*
1490 * update root item of reloc tree
1491 */
1492 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1493 struct btrfs_root *root)
1494 {
1495 struct btrfs_fs_info *fs_info = root->fs_info;
1496 struct btrfs_root *reloc_root;
1497 struct btrfs_root_item *root_item;
1498 int ret;
1499
1500 if (!root->reloc_root)
1501 goto out;
1502
1503 reloc_root = root->reloc_root;
1504 root_item = &reloc_root->root_item;
1505
1506 if (fs_info->reloc_ctl->merge_reloc_tree &&
1507 btrfs_root_refs(root_item) == 0) {
1508 root->reloc_root = NULL;
1509 __del_reloc_root(reloc_root);
1510 }
1511
1512 if (reloc_root->commit_root != reloc_root->node) {
1513 btrfs_set_root_node(root_item, reloc_root->node);
1514 free_extent_buffer(reloc_root->commit_root);
1515 reloc_root->commit_root = btrfs_root_node(reloc_root);
1516 }
1517
1518 ret = btrfs_update_root(trans, fs_info->tree_root,
1519 &reloc_root->root_key, root_item);
1520 BUG_ON(ret);
1521
1522 out:
1523 return 0;
1524 }
1525
1526 /*
1527 * helper to find first cached inode with inode number >= objectid
1528 * in a subvolume
1529 */
1530 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1531 {
1532 struct rb_node *node;
1533 struct rb_node *prev;
1534 struct btrfs_inode *entry;
1535 struct inode *inode;
1536
1537 spin_lock(&root->inode_lock);
1538 again:
1539 node = root->inode_tree.rb_node;
1540 prev = NULL;
1541 while (node) {
1542 prev = node;
1543 entry = rb_entry(node, struct btrfs_inode, rb_node);
1544
1545 if (objectid < btrfs_ino(entry))
1546 node = node->rb_left;
1547 else if (objectid > btrfs_ino(entry))
1548 node = node->rb_right;
1549 else
1550 break;
1551 }
1552 if (!node) {
1553 while (prev) {
1554 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1555 if (objectid <= btrfs_ino(entry)) {
1556 node = prev;
1557 break;
1558 }
1559 prev = rb_next(prev);
1560 }
1561 }
1562 while (node) {
1563 entry = rb_entry(node, struct btrfs_inode, rb_node);
1564 inode = igrab(&entry->vfs_inode);
1565 if (inode) {
1566 spin_unlock(&root->inode_lock);
1567 return inode;
1568 }
1569
1570 objectid = btrfs_ino(entry) + 1;
1571 if (cond_resched_lock(&root->inode_lock))
1572 goto again;
1573
1574 node = rb_next(node);
1575 }
1576 spin_unlock(&root->inode_lock);
1577 return NULL;
1578 }
1579
1580 static int in_block_group(u64 bytenr,
1581 struct btrfs_block_group_cache *block_group)
1582 {
1583 if (bytenr >= block_group->key.objectid &&
1584 bytenr < block_group->key.objectid + block_group->key.offset)
1585 return 1;
1586 return 0;
1587 }
1588
1589 /*
1590 * get new location of data
1591 */
1592 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1593 u64 bytenr, u64 num_bytes)
1594 {
1595 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1596 struct btrfs_path *path;
1597 struct btrfs_file_extent_item *fi;
1598 struct extent_buffer *leaf;
1599 int ret;
1600
1601 path = btrfs_alloc_path();
1602 if (!path)
1603 return -ENOMEM;
1604
1605 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1606 ret = btrfs_lookup_file_extent(NULL, root, path,
1607 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1608 if (ret < 0)
1609 goto out;
1610 if (ret > 0) {
1611 ret = -ENOENT;
1612 goto out;
1613 }
1614
1615 leaf = path->nodes[0];
1616 fi = btrfs_item_ptr(leaf, path->slots[0],
1617 struct btrfs_file_extent_item);
1618
1619 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1620 btrfs_file_extent_compression(leaf, fi) ||
1621 btrfs_file_extent_encryption(leaf, fi) ||
1622 btrfs_file_extent_other_encoding(leaf, fi));
1623
1624 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1625 ret = -EINVAL;
1626 goto out;
1627 }
1628
1629 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1630 ret = 0;
1631 out:
1632 btrfs_free_path(path);
1633 return ret;
1634 }
1635
1636 /*
1637 * update file extent items in the tree leaf to point to
1638 * the new locations.
1639 */
1640 static noinline_for_stack
1641 int replace_file_extents(struct btrfs_trans_handle *trans,
1642 struct reloc_control *rc,
1643 struct btrfs_root *root,
1644 struct extent_buffer *leaf)
1645 {
1646 struct btrfs_fs_info *fs_info = root->fs_info;
1647 struct btrfs_key key;
1648 struct btrfs_file_extent_item *fi;
1649 struct inode *inode = NULL;
1650 u64 parent;
1651 u64 bytenr;
1652 u64 new_bytenr = 0;
1653 u64 num_bytes;
1654 u64 end;
1655 u32 nritems;
1656 u32 i;
1657 int ret = 0;
1658 int first = 1;
1659 int dirty = 0;
1660
1661 if (rc->stage != UPDATE_DATA_PTRS)
1662 return 0;
1663
1664 /* reloc trees always use full backref */
1665 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1666 parent = leaf->start;
1667 else
1668 parent = 0;
1669
1670 nritems = btrfs_header_nritems(leaf);
1671 for (i = 0; i < nritems; i++) {
1672 cond_resched();
1673 btrfs_item_key_to_cpu(leaf, &key, i);
1674 if (key.type != BTRFS_EXTENT_DATA_KEY)
1675 continue;
1676 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1677 if (btrfs_file_extent_type(leaf, fi) ==
1678 BTRFS_FILE_EXTENT_INLINE)
1679 continue;
1680 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1681 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1682 if (bytenr == 0)
1683 continue;
1684 if (!in_block_group(bytenr, rc->block_group))
1685 continue;
1686
1687 /*
1688 * if we are modifying block in fs tree, wait for readpage
1689 * to complete and drop the extent cache
1690 */
1691 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1692 if (first) {
1693 inode = find_next_inode(root, key.objectid);
1694 first = 0;
1695 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1696 btrfs_add_delayed_iput(inode);
1697 inode = find_next_inode(root, key.objectid);
1698 }
1699 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1700 end = key.offset +
1701 btrfs_file_extent_num_bytes(leaf, fi);
1702 WARN_ON(!IS_ALIGNED(key.offset,
1703 fs_info->sectorsize));
1704 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1705 end--;
1706 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1707 key.offset, end);
1708 if (!ret)
1709 continue;
1710
1711 btrfs_drop_extent_cache(BTRFS_I(inode),
1712 key.offset, end, 1);
1713 unlock_extent(&BTRFS_I(inode)->io_tree,
1714 key.offset, end);
1715 }
1716 }
1717
1718 ret = get_new_location(rc->data_inode, &new_bytenr,
1719 bytenr, num_bytes);
1720 if (ret) {
1721 /*
1722 * Don't have to abort since we've not changed anything
1723 * in the file extent yet.
1724 */
1725 break;
1726 }
1727
1728 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1729 dirty = 1;
1730
1731 key.offset -= btrfs_file_extent_offset(leaf, fi);
1732 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1733 num_bytes, parent,
1734 btrfs_header_owner(leaf),
1735 key.objectid, key.offset);
1736 if (ret) {
1737 btrfs_abort_transaction(trans, ret);
1738 break;
1739 }
1740
1741 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1742 parent, btrfs_header_owner(leaf),
1743 key.objectid, key.offset);
1744 if (ret) {
1745 btrfs_abort_transaction(trans, ret);
1746 break;
1747 }
1748 }
1749 if (dirty)
1750 btrfs_mark_buffer_dirty(leaf);
1751 if (inode)
1752 btrfs_add_delayed_iput(inode);
1753 return ret;
1754 }
1755
1756 static noinline_for_stack
1757 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1758 struct btrfs_path *path, int level)
1759 {
1760 struct btrfs_disk_key key1;
1761 struct btrfs_disk_key key2;
1762 btrfs_node_key(eb, &key1, slot);
1763 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1764 return memcmp(&key1, &key2, sizeof(key1));
1765 }
1766
1767 /*
1768 * try to replace tree blocks in fs tree with the new blocks
1769 * in reloc tree. tree blocks haven't been modified since the
1770 * reloc tree was create can be replaced.
1771 *
1772 * if a block was replaced, level of the block + 1 is returned.
1773 * if no block got replaced, 0 is returned. if there are other
1774 * errors, a negative error number is returned.
1775 */
1776 static noinline_for_stack
1777 int replace_path(struct btrfs_trans_handle *trans,
1778 struct btrfs_root *dest, struct btrfs_root *src,
1779 struct btrfs_path *path, struct btrfs_key *next_key,
1780 int lowest_level, int max_level)
1781 {
1782 struct btrfs_fs_info *fs_info = dest->fs_info;
1783 struct extent_buffer *eb;
1784 struct extent_buffer *parent;
1785 struct btrfs_key key;
1786 u64 old_bytenr;
1787 u64 new_bytenr;
1788 u64 old_ptr_gen;
1789 u64 new_ptr_gen;
1790 u64 last_snapshot;
1791 u32 blocksize;
1792 int cow = 0;
1793 int level;
1794 int ret;
1795 int slot;
1796
1797 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1798 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1799
1800 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1801 again:
1802 slot = path->slots[lowest_level];
1803 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1804
1805 eb = btrfs_lock_root_node(dest);
1806 btrfs_set_lock_blocking(eb);
1807 level = btrfs_header_level(eb);
1808
1809 if (level < lowest_level) {
1810 btrfs_tree_unlock(eb);
1811 free_extent_buffer(eb);
1812 return 0;
1813 }
1814
1815 if (cow) {
1816 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1817 BUG_ON(ret);
1818 }
1819 btrfs_set_lock_blocking(eb);
1820
1821 if (next_key) {
1822 next_key->objectid = (u64)-1;
1823 next_key->type = (u8)-1;
1824 next_key->offset = (u64)-1;
1825 }
1826
1827 parent = eb;
1828 while (1) {
1829 struct btrfs_key first_key;
1830
1831 level = btrfs_header_level(parent);
1832 BUG_ON(level < lowest_level);
1833
1834 ret = btrfs_bin_search(parent, &key, level, &slot);
1835 if (ret && slot > 0)
1836 slot--;
1837
1838 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1839 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1840
1841 old_bytenr = btrfs_node_blockptr(parent, slot);
1842 blocksize = fs_info->nodesize;
1843 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1844 btrfs_node_key_to_cpu(parent, &first_key, slot);
1845
1846 if (level <= max_level) {
1847 eb = path->nodes[level];
1848 new_bytenr = btrfs_node_blockptr(eb,
1849 path->slots[level]);
1850 new_ptr_gen = btrfs_node_ptr_generation(eb,
1851 path->slots[level]);
1852 } else {
1853 new_bytenr = 0;
1854 new_ptr_gen = 0;
1855 }
1856
1857 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1858 ret = level;
1859 break;
1860 }
1861
1862 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1863 memcmp_node_keys(parent, slot, path, level)) {
1864 if (level <= lowest_level) {
1865 ret = 0;
1866 break;
1867 }
1868
1869 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1870 level - 1, &first_key);
1871 if (IS_ERR(eb)) {
1872 ret = PTR_ERR(eb);
1873 break;
1874 } else if (!extent_buffer_uptodate(eb)) {
1875 ret = -EIO;
1876 free_extent_buffer(eb);
1877 break;
1878 }
1879 btrfs_tree_lock(eb);
1880 if (cow) {
1881 ret = btrfs_cow_block(trans, dest, eb, parent,
1882 slot, &eb);
1883 BUG_ON(ret);
1884 }
1885 btrfs_set_lock_blocking(eb);
1886
1887 btrfs_tree_unlock(parent);
1888 free_extent_buffer(parent);
1889
1890 parent = eb;
1891 continue;
1892 }
1893
1894 if (!cow) {
1895 btrfs_tree_unlock(parent);
1896 free_extent_buffer(parent);
1897 cow = 1;
1898 goto again;
1899 }
1900
1901 btrfs_node_key_to_cpu(path->nodes[level], &key,
1902 path->slots[level]);
1903 btrfs_release_path(path);
1904
1905 path->lowest_level = level;
1906 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1907 path->lowest_level = 0;
1908 BUG_ON(ret);
1909
1910 /*
1911 * Info qgroup to trace both subtrees.
1912 *
1913 * We must trace both trees.
1914 * 1) Tree reloc subtree
1915 * If not traced, we will leak data numbers
1916 * 2) Fs subtree
1917 * If not traced, we will double count old data
1918 * and tree block numbers, if current trans doesn't free
1919 * data reloc tree inode.
1920 */
1921 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1922 btrfs_header_generation(parent),
1923 btrfs_header_level(parent));
1924 if (ret < 0)
1925 break;
1926 ret = btrfs_qgroup_trace_subtree(trans, dest,
1927 path->nodes[level],
1928 btrfs_header_generation(path->nodes[level]),
1929 btrfs_header_level(path->nodes[level]));
1930 if (ret < 0)
1931 break;
1932
1933 /*
1934 * swap blocks in fs tree and reloc tree.
1935 */
1936 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1937 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1938 btrfs_mark_buffer_dirty(parent);
1939
1940 btrfs_set_node_blockptr(path->nodes[level],
1941 path->slots[level], old_bytenr);
1942 btrfs_set_node_ptr_generation(path->nodes[level],
1943 path->slots[level], old_ptr_gen);
1944 btrfs_mark_buffer_dirty(path->nodes[level]);
1945
1946 ret = btrfs_inc_extent_ref(trans, src, old_bytenr,
1947 blocksize, path->nodes[level]->start,
1948 src->root_key.objectid, level - 1, 0);
1949 BUG_ON(ret);
1950 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr,
1951 blocksize, 0, dest->root_key.objectid,
1952 level - 1, 0);
1953 BUG_ON(ret);
1954
1955 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1956 path->nodes[level]->start,
1957 src->root_key.objectid, level - 1, 0);
1958 BUG_ON(ret);
1959
1960 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1961 0, dest->root_key.objectid, level - 1,
1962 0);
1963 BUG_ON(ret);
1964
1965 btrfs_unlock_up_safe(path, 0);
1966
1967 ret = level;
1968 break;
1969 }
1970 btrfs_tree_unlock(parent);
1971 free_extent_buffer(parent);
1972 return ret;
1973 }
1974
1975 /*
1976 * helper to find next relocated block in reloc tree
1977 */
1978 static noinline_for_stack
1979 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1980 int *level)
1981 {
1982 struct extent_buffer *eb;
1983 int i;
1984 u64 last_snapshot;
1985 u32 nritems;
1986
1987 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1988
1989 for (i = 0; i < *level; i++) {
1990 free_extent_buffer(path->nodes[i]);
1991 path->nodes[i] = NULL;
1992 }
1993
1994 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1995 eb = path->nodes[i];
1996 nritems = btrfs_header_nritems(eb);
1997 while (path->slots[i] + 1 < nritems) {
1998 path->slots[i]++;
1999 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2000 last_snapshot)
2001 continue;
2002
2003 *level = i;
2004 return 0;
2005 }
2006 free_extent_buffer(path->nodes[i]);
2007 path->nodes[i] = NULL;
2008 }
2009 return 1;
2010 }
2011
2012 /*
2013 * walk down reloc tree to find relocated block of lowest level
2014 */
2015 static noinline_for_stack
2016 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2017 int *level)
2018 {
2019 struct btrfs_fs_info *fs_info = root->fs_info;
2020 struct extent_buffer *eb = NULL;
2021 int i;
2022 u64 bytenr;
2023 u64 ptr_gen = 0;
2024 u64 last_snapshot;
2025 u32 nritems;
2026
2027 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2028
2029 for (i = *level; i > 0; i--) {
2030 struct btrfs_key first_key;
2031
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 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2053 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2054 &first_key);
2055 if (IS_ERR(eb)) {
2056 return PTR_ERR(eb);
2057 } else if (!extent_buffer_uptodate(eb)) {
2058 free_extent_buffer(eb);
2059 return -EIO;
2060 }
2061 BUG_ON(btrfs_header_level(eb) != i - 1);
2062 path->nodes[i - 1] = eb;
2063 path->slots[i - 1] = 0;
2064 }
2065 return 1;
2066 }
2067
2068 /*
2069 * invalidate extent cache for file extents whose key in range of
2070 * [min_key, max_key)
2071 */
2072 static int invalidate_extent_cache(struct btrfs_root *root,
2073 struct btrfs_key *min_key,
2074 struct btrfs_key *max_key)
2075 {
2076 struct btrfs_fs_info *fs_info = root->fs_info;
2077 struct inode *inode = NULL;
2078 u64 objectid;
2079 u64 start, end;
2080 u64 ino;
2081
2082 objectid = min_key->objectid;
2083 while (1) {
2084 cond_resched();
2085 iput(inode);
2086
2087 if (objectid > max_key->objectid)
2088 break;
2089
2090 inode = find_next_inode(root, objectid);
2091 if (!inode)
2092 break;
2093 ino = btrfs_ino(BTRFS_I(inode));
2094
2095 if (ino > max_key->objectid) {
2096 iput(inode);
2097 break;
2098 }
2099
2100 objectid = ino + 1;
2101 if (!S_ISREG(inode->i_mode))
2102 continue;
2103
2104 if (unlikely(min_key->objectid == ino)) {
2105 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2106 continue;
2107 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2108 start = 0;
2109 else {
2110 start = min_key->offset;
2111 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2112 }
2113 } else {
2114 start = 0;
2115 }
2116
2117 if (unlikely(max_key->objectid == ino)) {
2118 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2119 continue;
2120 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2121 end = (u64)-1;
2122 } else {
2123 if (max_key->offset == 0)
2124 continue;
2125 end = max_key->offset;
2126 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2127 end--;
2128 }
2129 } else {
2130 end = (u64)-1;
2131 }
2132
2133 /* the lock_extent waits for readpage to complete */
2134 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2135 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2136 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2137 }
2138 return 0;
2139 }
2140
2141 static int find_next_key(struct btrfs_path *path, int level,
2142 struct btrfs_key *key)
2143
2144 {
2145 while (level < BTRFS_MAX_LEVEL) {
2146 if (!path->nodes[level])
2147 break;
2148 if (path->slots[level] + 1 <
2149 btrfs_header_nritems(path->nodes[level])) {
2150 btrfs_node_key_to_cpu(path->nodes[level], key,
2151 path->slots[level] + 1);
2152 return 0;
2153 }
2154 level++;
2155 }
2156 return 1;
2157 }
2158
2159 /*
2160 * merge the relocated tree blocks in reloc tree with corresponding
2161 * fs tree.
2162 */
2163 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2164 struct btrfs_root *root)
2165 {
2166 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2167 LIST_HEAD(inode_list);
2168 struct btrfs_key key;
2169 struct btrfs_key next_key;
2170 struct btrfs_trans_handle *trans = NULL;
2171 struct btrfs_root *reloc_root;
2172 struct btrfs_root_item *root_item;
2173 struct btrfs_path *path;
2174 struct extent_buffer *leaf;
2175 int level;
2176 int max_level;
2177 int replaced = 0;
2178 int ret;
2179 int err = 0;
2180 u32 min_reserved;
2181
2182 path = btrfs_alloc_path();
2183 if (!path)
2184 return -ENOMEM;
2185 path->reada = READA_FORWARD;
2186
2187 reloc_root = root->reloc_root;
2188 root_item = &reloc_root->root_item;
2189
2190 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2191 level = btrfs_root_level(root_item);
2192 extent_buffer_get(reloc_root->node);
2193 path->nodes[level] = reloc_root->node;
2194 path->slots[level] = 0;
2195 } else {
2196 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2197
2198 level = root_item->drop_level;
2199 BUG_ON(level == 0);
2200 path->lowest_level = level;
2201 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2202 path->lowest_level = 0;
2203 if (ret < 0) {
2204 btrfs_free_path(path);
2205 return ret;
2206 }
2207
2208 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2209 path->slots[level]);
2210 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2211
2212 btrfs_unlock_up_safe(path, 0);
2213 }
2214
2215 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2216 memset(&next_key, 0, sizeof(next_key));
2217
2218 while (1) {
2219 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2220 BTRFS_RESERVE_FLUSH_ALL);
2221 if (ret) {
2222 err = ret;
2223 goto out;
2224 }
2225 trans = btrfs_start_transaction(root, 0);
2226 if (IS_ERR(trans)) {
2227 err = PTR_ERR(trans);
2228 trans = NULL;
2229 goto out;
2230 }
2231 trans->block_rsv = rc->block_rsv;
2232
2233 replaced = 0;
2234 max_level = level;
2235
2236 ret = walk_down_reloc_tree(reloc_root, path, &level);
2237 if (ret < 0) {
2238 err = ret;
2239 goto out;
2240 }
2241 if (ret > 0)
2242 break;
2243
2244 if (!find_next_key(path, level, &key) &&
2245 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2246 ret = 0;
2247 } else {
2248 ret = replace_path(trans, root, reloc_root, path,
2249 &next_key, level, max_level);
2250 }
2251 if (ret < 0) {
2252 err = ret;
2253 goto out;
2254 }
2255
2256 if (ret > 0) {
2257 level = ret;
2258 btrfs_node_key_to_cpu(path->nodes[level], &key,
2259 path->slots[level]);
2260 replaced = 1;
2261 }
2262
2263 ret = walk_up_reloc_tree(reloc_root, path, &level);
2264 if (ret > 0)
2265 break;
2266
2267 BUG_ON(level == 0);
2268 /*
2269 * save the merging progress in the drop_progress.
2270 * this is OK since root refs == 1 in this case.
2271 */
2272 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2273 path->slots[level]);
2274 root_item->drop_level = level;
2275
2276 btrfs_end_transaction_throttle(trans);
2277 trans = NULL;
2278
2279 btrfs_btree_balance_dirty(fs_info);
2280
2281 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2282 invalidate_extent_cache(root, &key, &next_key);
2283 }
2284
2285 /*
2286 * handle the case only one block in the fs tree need to be
2287 * relocated and the block is tree root.
2288 */
2289 leaf = btrfs_lock_root_node(root);
2290 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2291 btrfs_tree_unlock(leaf);
2292 free_extent_buffer(leaf);
2293 if (ret < 0)
2294 err = ret;
2295 out:
2296 btrfs_free_path(path);
2297
2298 if (err == 0) {
2299 memset(&root_item->drop_progress, 0,
2300 sizeof(root_item->drop_progress));
2301 root_item->drop_level = 0;
2302 btrfs_set_root_refs(root_item, 0);
2303 btrfs_update_reloc_root(trans, root);
2304 }
2305
2306 if (trans)
2307 btrfs_end_transaction_throttle(trans);
2308
2309 btrfs_btree_balance_dirty(fs_info);
2310
2311 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2312 invalidate_extent_cache(root, &key, &next_key);
2313
2314 return err;
2315 }
2316
2317 static noinline_for_stack
2318 int prepare_to_merge(struct reloc_control *rc, int err)
2319 {
2320 struct btrfs_root *root = rc->extent_root;
2321 struct btrfs_fs_info *fs_info = root->fs_info;
2322 struct btrfs_root *reloc_root;
2323 struct btrfs_trans_handle *trans;
2324 LIST_HEAD(reloc_roots);
2325 u64 num_bytes = 0;
2326 int ret;
2327
2328 mutex_lock(&fs_info->reloc_mutex);
2329 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2330 rc->merging_rsv_size += rc->nodes_relocated * 2;
2331 mutex_unlock(&fs_info->reloc_mutex);
2332
2333 again:
2334 if (!err) {
2335 num_bytes = rc->merging_rsv_size;
2336 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2337 BTRFS_RESERVE_FLUSH_ALL);
2338 if (ret)
2339 err = ret;
2340 }
2341
2342 trans = btrfs_join_transaction(rc->extent_root);
2343 if (IS_ERR(trans)) {
2344 if (!err)
2345 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2346 num_bytes);
2347 return PTR_ERR(trans);
2348 }
2349
2350 if (!err) {
2351 if (num_bytes != rc->merging_rsv_size) {
2352 btrfs_end_transaction(trans);
2353 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2354 num_bytes);
2355 goto again;
2356 }
2357 }
2358
2359 rc->merge_reloc_tree = 1;
2360
2361 while (!list_empty(&rc->reloc_roots)) {
2362 reloc_root = list_entry(rc->reloc_roots.next,
2363 struct btrfs_root, root_list);
2364 list_del_init(&reloc_root->root_list);
2365
2366 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2367 BUG_ON(IS_ERR(root));
2368 BUG_ON(root->reloc_root != reloc_root);
2369
2370 /*
2371 * set reference count to 1, so btrfs_recover_relocation
2372 * knows it should resumes merging
2373 */
2374 if (!err)
2375 btrfs_set_root_refs(&reloc_root->root_item, 1);
2376 btrfs_update_reloc_root(trans, root);
2377
2378 list_add(&reloc_root->root_list, &reloc_roots);
2379 }
2380
2381 list_splice(&reloc_roots, &rc->reloc_roots);
2382
2383 if (!err)
2384 btrfs_commit_transaction(trans);
2385 else
2386 btrfs_end_transaction(trans);
2387 return err;
2388 }
2389
2390 static noinline_for_stack
2391 void free_reloc_roots(struct list_head *list)
2392 {
2393 struct btrfs_root *reloc_root;
2394
2395 while (!list_empty(list)) {
2396 reloc_root = list_entry(list->next, struct btrfs_root,
2397 root_list);
2398 __del_reloc_root(reloc_root);
2399 free_extent_buffer(reloc_root->node);
2400 free_extent_buffer(reloc_root->commit_root);
2401 reloc_root->node = NULL;
2402 reloc_root->commit_root = NULL;
2403 }
2404 }
2405
2406 static noinline_for_stack
2407 void merge_reloc_roots(struct reloc_control *rc)
2408 {
2409 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2410 struct btrfs_root *root;
2411 struct btrfs_root *reloc_root;
2412 LIST_HEAD(reloc_roots);
2413 int found = 0;
2414 int ret = 0;
2415 again:
2416 root = rc->extent_root;
2417
2418 /*
2419 * this serializes us with btrfs_record_root_in_transaction,
2420 * we have to make sure nobody is in the middle of
2421 * adding their roots to the list while we are
2422 * doing this splice
2423 */
2424 mutex_lock(&fs_info->reloc_mutex);
2425 list_splice_init(&rc->reloc_roots, &reloc_roots);
2426 mutex_unlock(&fs_info->reloc_mutex);
2427
2428 while (!list_empty(&reloc_roots)) {
2429 found = 1;
2430 reloc_root = list_entry(reloc_roots.next,
2431 struct btrfs_root, root_list);
2432
2433 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2434 root = read_fs_root(fs_info,
2435 reloc_root->root_key.offset);
2436 BUG_ON(IS_ERR(root));
2437 BUG_ON(root->reloc_root != reloc_root);
2438
2439 ret = merge_reloc_root(rc, root);
2440 if (ret) {
2441 if (list_empty(&reloc_root->root_list))
2442 list_add_tail(&reloc_root->root_list,
2443 &reloc_roots);
2444 goto out;
2445 }
2446 } else {
2447 list_del_init(&reloc_root->root_list);
2448 }
2449
2450 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2451 if (ret < 0) {
2452 if (list_empty(&reloc_root->root_list))
2453 list_add_tail(&reloc_root->root_list,
2454 &reloc_roots);
2455 goto out;
2456 }
2457 }
2458
2459 if (found) {
2460 found = 0;
2461 goto again;
2462 }
2463 out:
2464 if (ret) {
2465 btrfs_handle_fs_error(fs_info, ret, NULL);
2466 if (!list_empty(&reloc_roots))
2467 free_reloc_roots(&reloc_roots);
2468
2469 /* new reloc root may be added */
2470 mutex_lock(&fs_info->reloc_mutex);
2471 list_splice_init(&rc->reloc_roots, &reloc_roots);
2472 mutex_unlock(&fs_info->reloc_mutex);
2473 if (!list_empty(&reloc_roots))
2474 free_reloc_roots(&reloc_roots);
2475 }
2476
2477 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2478 }
2479
2480 static void free_block_list(struct rb_root *blocks)
2481 {
2482 struct tree_block *block;
2483 struct rb_node *rb_node;
2484 while ((rb_node = rb_first(blocks))) {
2485 block = rb_entry(rb_node, struct tree_block, rb_node);
2486 rb_erase(rb_node, blocks);
2487 kfree(block);
2488 }
2489 }
2490
2491 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2492 struct btrfs_root *reloc_root)
2493 {
2494 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2495 struct btrfs_root *root;
2496
2497 if (reloc_root->last_trans == trans->transid)
2498 return 0;
2499
2500 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2501 BUG_ON(IS_ERR(root));
2502 BUG_ON(root->reloc_root != reloc_root);
2503
2504 return btrfs_record_root_in_trans(trans, root);
2505 }
2506
2507 static noinline_for_stack
2508 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2509 struct reloc_control *rc,
2510 struct backref_node *node,
2511 struct backref_edge *edges[])
2512 {
2513 struct backref_node *next;
2514 struct btrfs_root *root;
2515 int index = 0;
2516
2517 next = node;
2518 while (1) {
2519 cond_resched();
2520 next = walk_up_backref(next, edges, &index);
2521 root = next->root;
2522 BUG_ON(!root);
2523 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2524
2525 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2526 record_reloc_root_in_trans(trans, root);
2527 break;
2528 }
2529
2530 btrfs_record_root_in_trans(trans, root);
2531 root = root->reloc_root;
2532
2533 if (next->new_bytenr != root->node->start) {
2534 BUG_ON(next->new_bytenr);
2535 BUG_ON(!list_empty(&next->list));
2536 next->new_bytenr = root->node->start;
2537 next->root = root;
2538 list_add_tail(&next->list,
2539 &rc->backref_cache.changed);
2540 __mark_block_processed(rc, next);
2541 break;
2542 }
2543
2544 WARN_ON(1);
2545 root = NULL;
2546 next = walk_down_backref(edges, &index);
2547 if (!next || next->level <= node->level)
2548 break;
2549 }
2550 if (!root)
2551 return NULL;
2552
2553 next = node;
2554 /* setup backref node path for btrfs_reloc_cow_block */
2555 while (1) {
2556 rc->backref_cache.path[next->level] = next;
2557 if (--index < 0)
2558 break;
2559 next = edges[index]->node[UPPER];
2560 }
2561 return root;
2562 }
2563
2564 /*
2565 * select a tree root for relocation. return NULL if the block
2566 * is reference counted. we should use do_relocation() in this
2567 * case. return a tree root pointer if the block isn't reference
2568 * counted. return -ENOENT if the block is root of reloc tree.
2569 */
2570 static noinline_for_stack
2571 struct btrfs_root *select_one_root(struct backref_node *node)
2572 {
2573 struct backref_node *next;
2574 struct btrfs_root *root;
2575 struct btrfs_root *fs_root = NULL;
2576 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2577 int index = 0;
2578
2579 next = node;
2580 while (1) {
2581 cond_resched();
2582 next = walk_up_backref(next, edges, &index);
2583 root = next->root;
2584 BUG_ON(!root);
2585
2586 /* no other choice for non-references counted tree */
2587 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2588 return root;
2589
2590 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2591 fs_root = root;
2592
2593 if (next != node)
2594 return NULL;
2595
2596 next = walk_down_backref(edges, &index);
2597 if (!next || next->level <= node->level)
2598 break;
2599 }
2600
2601 if (!fs_root)
2602 return ERR_PTR(-ENOENT);
2603 return fs_root;
2604 }
2605
2606 static noinline_for_stack
2607 u64 calcu_metadata_size(struct reloc_control *rc,
2608 struct backref_node *node, int reserve)
2609 {
2610 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2611 struct backref_node *next = node;
2612 struct backref_edge *edge;
2613 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2614 u64 num_bytes = 0;
2615 int index = 0;
2616
2617 BUG_ON(reserve && node->processed);
2618
2619 while (next) {
2620 cond_resched();
2621 while (1) {
2622 if (next->processed && (reserve || next != node))
2623 break;
2624
2625 num_bytes += fs_info->nodesize;
2626
2627 if (list_empty(&next->upper))
2628 break;
2629
2630 edge = list_entry(next->upper.next,
2631 struct backref_edge, list[LOWER]);
2632 edges[index++] = edge;
2633 next = edge->node[UPPER];
2634 }
2635 next = walk_down_backref(edges, &index);
2636 }
2637 return num_bytes;
2638 }
2639
2640 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2641 struct reloc_control *rc,
2642 struct backref_node *node)
2643 {
2644 struct btrfs_root *root = rc->extent_root;
2645 struct btrfs_fs_info *fs_info = root->fs_info;
2646 u64 num_bytes;
2647 int ret;
2648 u64 tmp;
2649
2650 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2651
2652 trans->block_rsv = rc->block_rsv;
2653 rc->reserved_bytes += num_bytes;
2654
2655 /*
2656 * We are under a transaction here so we can only do limited flushing.
2657 * If we get an enospc just kick back -EAGAIN so we know to drop the
2658 * transaction and try to refill when we can flush all the things.
2659 */
2660 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2661 BTRFS_RESERVE_FLUSH_LIMIT);
2662 if (ret) {
2663 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2664 while (tmp <= rc->reserved_bytes)
2665 tmp <<= 1;
2666 /*
2667 * only one thread can access block_rsv at this point,
2668 * so we don't need hold lock to protect block_rsv.
2669 * we expand more reservation size here to allow enough
2670 * space for relocation and we will return eailer in
2671 * enospc case.
2672 */
2673 rc->block_rsv->size = tmp + fs_info->nodesize *
2674 RELOCATION_RESERVED_NODES;
2675 return -EAGAIN;
2676 }
2677
2678 return 0;
2679 }
2680
2681 /*
2682 * relocate a block tree, and then update pointers in upper level
2683 * blocks that reference the block to point to the new location.
2684 *
2685 * if called by link_to_upper, the block has already been relocated.
2686 * in that case this function just updates pointers.
2687 */
2688 static int do_relocation(struct btrfs_trans_handle *trans,
2689 struct reloc_control *rc,
2690 struct backref_node *node,
2691 struct btrfs_key *key,
2692 struct btrfs_path *path, int lowest)
2693 {
2694 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2695 struct backref_node *upper;
2696 struct backref_edge *edge;
2697 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2698 struct btrfs_root *root;
2699 struct extent_buffer *eb;
2700 u32 blocksize;
2701 u64 bytenr;
2702 u64 generation;
2703 int slot;
2704 int ret;
2705 int err = 0;
2706
2707 BUG_ON(lowest && node->eb);
2708
2709 path->lowest_level = node->level + 1;
2710 rc->backref_cache.path[node->level] = node;
2711 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2712 struct btrfs_key first_key;
2713
2714 cond_resched();
2715
2716 upper = edge->node[UPPER];
2717 root = select_reloc_root(trans, rc, upper, edges);
2718 BUG_ON(!root);
2719
2720 if (upper->eb && !upper->locked) {
2721 if (!lowest) {
2722 ret = btrfs_bin_search(upper->eb, key,
2723 upper->level, &slot);
2724 BUG_ON(ret);
2725 bytenr = btrfs_node_blockptr(upper->eb, slot);
2726 if (node->eb->start == bytenr)
2727 goto next;
2728 }
2729 drop_node_buffer(upper);
2730 }
2731
2732 if (!upper->eb) {
2733 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2734 if (ret) {
2735 if (ret < 0)
2736 err = ret;
2737 else
2738 err = -ENOENT;
2739
2740 btrfs_release_path(path);
2741 break;
2742 }
2743
2744 if (!upper->eb) {
2745 upper->eb = path->nodes[upper->level];
2746 path->nodes[upper->level] = NULL;
2747 } else {
2748 BUG_ON(upper->eb != path->nodes[upper->level]);
2749 }
2750
2751 upper->locked = 1;
2752 path->locks[upper->level] = 0;
2753
2754 slot = path->slots[upper->level];
2755 btrfs_release_path(path);
2756 } else {
2757 ret = btrfs_bin_search(upper->eb, key, upper->level,
2758 &slot);
2759 BUG_ON(ret);
2760 }
2761
2762 bytenr = btrfs_node_blockptr(upper->eb, slot);
2763 if (lowest) {
2764 if (bytenr != node->bytenr) {
2765 btrfs_err(root->fs_info,
2766 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2767 bytenr, node->bytenr, slot,
2768 upper->eb->start);
2769 err = -EIO;
2770 goto next;
2771 }
2772 } else {
2773 if (node->eb->start == bytenr)
2774 goto next;
2775 }
2776
2777 blocksize = root->fs_info->nodesize;
2778 generation = btrfs_node_ptr_generation(upper->eb, slot);
2779 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2780 eb = read_tree_block(fs_info, bytenr, generation,
2781 upper->level - 1, &first_key);
2782 if (IS_ERR(eb)) {
2783 err = PTR_ERR(eb);
2784 goto next;
2785 } else if (!extent_buffer_uptodate(eb)) {
2786 free_extent_buffer(eb);
2787 err = -EIO;
2788 goto next;
2789 }
2790 btrfs_tree_lock(eb);
2791 btrfs_set_lock_blocking(eb);
2792
2793 if (!node->eb) {
2794 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2795 slot, &eb);
2796 btrfs_tree_unlock(eb);
2797 free_extent_buffer(eb);
2798 if (ret < 0) {
2799 err = ret;
2800 goto next;
2801 }
2802 BUG_ON(node->eb != eb);
2803 } else {
2804 btrfs_set_node_blockptr(upper->eb, slot,
2805 node->eb->start);
2806 btrfs_set_node_ptr_generation(upper->eb, slot,
2807 trans->transid);
2808 btrfs_mark_buffer_dirty(upper->eb);
2809
2810 ret = btrfs_inc_extent_ref(trans, root,
2811 node->eb->start, blocksize,
2812 upper->eb->start,
2813 btrfs_header_owner(upper->eb),
2814 node->level, 0);
2815 BUG_ON(ret);
2816
2817 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2818 BUG_ON(ret);
2819 }
2820 next:
2821 if (!upper->pending)
2822 drop_node_buffer(upper);
2823 else
2824 unlock_node_buffer(upper);
2825 if (err)
2826 break;
2827 }
2828
2829 if (!err && node->pending) {
2830 drop_node_buffer(node);
2831 list_move_tail(&node->list, &rc->backref_cache.changed);
2832 node->pending = 0;
2833 }
2834
2835 path->lowest_level = 0;
2836 BUG_ON(err == -ENOSPC);
2837 return err;
2838 }
2839
2840 static int link_to_upper(struct btrfs_trans_handle *trans,
2841 struct reloc_control *rc,
2842 struct backref_node *node,
2843 struct btrfs_path *path)
2844 {
2845 struct btrfs_key key;
2846
2847 btrfs_node_key_to_cpu(node->eb, &key, 0);
2848 return do_relocation(trans, rc, node, &key, path, 0);
2849 }
2850
2851 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2852 struct reloc_control *rc,
2853 struct btrfs_path *path, int err)
2854 {
2855 LIST_HEAD(list);
2856 struct backref_cache *cache = &rc->backref_cache;
2857 struct backref_node *node;
2858 int level;
2859 int ret;
2860
2861 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2862 while (!list_empty(&cache->pending[level])) {
2863 node = list_entry(cache->pending[level].next,
2864 struct backref_node, list);
2865 list_move_tail(&node->list, &list);
2866 BUG_ON(!node->pending);
2867
2868 if (!err) {
2869 ret = link_to_upper(trans, rc, node, path);
2870 if (ret < 0)
2871 err = ret;
2872 }
2873 }
2874 list_splice_init(&list, &cache->pending[level]);
2875 }
2876 return err;
2877 }
2878
2879 static void mark_block_processed(struct reloc_control *rc,
2880 u64 bytenr, u32 blocksize)
2881 {
2882 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2883 EXTENT_DIRTY);
2884 }
2885
2886 static void __mark_block_processed(struct reloc_control *rc,
2887 struct backref_node *node)
2888 {
2889 u32 blocksize;
2890 if (node->level == 0 ||
2891 in_block_group(node->bytenr, rc->block_group)) {
2892 blocksize = rc->extent_root->fs_info->nodesize;
2893 mark_block_processed(rc, node->bytenr, blocksize);
2894 }
2895 node->processed = 1;
2896 }
2897
2898 /*
2899 * mark a block and all blocks directly/indirectly reference the block
2900 * as processed.
2901 */
2902 static void update_processed_blocks(struct reloc_control *rc,
2903 struct backref_node *node)
2904 {
2905 struct backref_node *next = node;
2906 struct backref_edge *edge;
2907 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2908 int index = 0;
2909
2910 while (next) {
2911 cond_resched();
2912 while (1) {
2913 if (next->processed)
2914 break;
2915
2916 __mark_block_processed(rc, next);
2917
2918 if (list_empty(&next->upper))
2919 break;
2920
2921 edge = list_entry(next->upper.next,
2922 struct backref_edge, list[LOWER]);
2923 edges[index++] = edge;
2924 next = edge->node[UPPER];
2925 }
2926 next = walk_down_backref(edges, &index);
2927 }
2928 }
2929
2930 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2931 {
2932 u32 blocksize = rc->extent_root->fs_info->nodesize;
2933
2934 if (test_range_bit(&rc->processed_blocks, bytenr,
2935 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2936 return 1;
2937 return 0;
2938 }
2939
2940 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2941 struct tree_block *block)
2942 {
2943 struct extent_buffer *eb;
2944
2945 BUG_ON(block->key_ready);
2946 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2947 block->level, NULL);
2948 if (IS_ERR(eb)) {
2949 return PTR_ERR(eb);
2950 } else if (!extent_buffer_uptodate(eb)) {
2951 free_extent_buffer(eb);
2952 return -EIO;
2953 }
2954 WARN_ON(btrfs_header_level(eb) != block->level);
2955 if (block->level == 0)
2956 btrfs_item_key_to_cpu(eb, &block->key, 0);
2957 else
2958 btrfs_node_key_to_cpu(eb, &block->key, 0);
2959 free_extent_buffer(eb);
2960 block->key_ready = 1;
2961 return 0;
2962 }
2963
2964 /*
2965 * helper function to relocate a tree block
2966 */
2967 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2968 struct reloc_control *rc,
2969 struct backref_node *node,
2970 struct btrfs_key *key,
2971 struct btrfs_path *path)
2972 {
2973 struct btrfs_root *root;
2974 int ret = 0;
2975
2976 if (!node)
2977 return 0;
2978
2979 BUG_ON(node->processed);
2980 root = select_one_root(node);
2981 if (root == ERR_PTR(-ENOENT)) {
2982 update_processed_blocks(rc, node);
2983 goto out;
2984 }
2985
2986 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2987 ret = reserve_metadata_space(trans, rc, node);
2988 if (ret)
2989 goto out;
2990 }
2991
2992 if (root) {
2993 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2994 BUG_ON(node->new_bytenr);
2995 BUG_ON(!list_empty(&node->list));
2996 btrfs_record_root_in_trans(trans, root);
2997 root = root->reloc_root;
2998 node->new_bytenr = root->node->start;
2999 node->root = root;
3000 list_add_tail(&node->list, &rc->backref_cache.changed);
3001 } else {
3002 path->lowest_level = node->level;
3003 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3004 btrfs_release_path(path);
3005 if (ret > 0)
3006 ret = 0;
3007 }
3008 if (!ret)
3009 update_processed_blocks(rc, node);
3010 } else {
3011 ret = do_relocation(trans, rc, node, key, path, 1);
3012 }
3013 out:
3014 if (ret || node->level == 0 || node->cowonly)
3015 remove_backref_node(&rc->backref_cache, node);
3016 return ret;
3017 }
3018
3019 /*
3020 * relocate a list of blocks
3021 */
3022 static noinline_for_stack
3023 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3024 struct reloc_control *rc, struct rb_root *blocks)
3025 {
3026 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3027 struct backref_node *node;
3028 struct btrfs_path *path;
3029 struct tree_block *block;
3030 struct rb_node *rb_node;
3031 int ret;
3032 int err = 0;
3033
3034 path = btrfs_alloc_path();
3035 if (!path) {
3036 err = -ENOMEM;
3037 goto out_free_blocks;
3038 }
3039
3040 rb_node = rb_first(blocks);
3041 while (rb_node) {
3042 block = rb_entry(rb_node, struct tree_block, rb_node);
3043 if (!block->key_ready)
3044 readahead_tree_block(fs_info, block->bytenr);
3045 rb_node = rb_next(rb_node);
3046 }
3047
3048 rb_node = rb_first(blocks);
3049 while (rb_node) {
3050 block = rb_entry(rb_node, struct tree_block, rb_node);
3051 if (!block->key_ready) {
3052 err = get_tree_block_key(fs_info, block);
3053 if (err)
3054 goto out_free_path;
3055 }
3056 rb_node = rb_next(rb_node);
3057 }
3058
3059 rb_node = rb_first(blocks);
3060 while (rb_node) {
3061 block = rb_entry(rb_node, struct tree_block, rb_node);
3062
3063 node = build_backref_tree(rc, &block->key,
3064 block->level, block->bytenr);
3065 if (IS_ERR(node)) {
3066 err = PTR_ERR(node);
3067 goto out;
3068 }
3069
3070 ret = relocate_tree_block(trans, rc, node, &block->key,
3071 path);
3072 if (ret < 0) {
3073 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3074 err = ret;
3075 goto out;
3076 }
3077 rb_node = rb_next(rb_node);
3078 }
3079 out:
3080 err = finish_pending_nodes(trans, rc, path, err);
3081
3082 out_free_path:
3083 btrfs_free_path(path);
3084 out_free_blocks:
3085 free_block_list(blocks);
3086 return err;
3087 }
3088
3089 static noinline_for_stack
3090 int prealloc_file_extent_cluster(struct inode *inode,
3091 struct file_extent_cluster *cluster)
3092 {
3093 u64 alloc_hint = 0;
3094 u64 start;
3095 u64 end;
3096 u64 offset = BTRFS_I(inode)->index_cnt;
3097 u64 num_bytes;
3098 int nr = 0;
3099 int ret = 0;
3100 u64 prealloc_start = cluster->start - offset;
3101 u64 prealloc_end = cluster->end - offset;
3102 u64 cur_offset;
3103 struct extent_changeset *data_reserved = NULL;
3104
3105 BUG_ON(cluster->start != cluster->boundary[0]);
3106 inode_lock(inode);
3107
3108 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3109 prealloc_end + 1 - prealloc_start);
3110 if (ret)
3111 goto out;
3112
3113 cur_offset = prealloc_start;
3114 while (nr < cluster->nr) {
3115 start = cluster->boundary[nr] - offset;
3116 if (nr + 1 < cluster->nr)
3117 end = cluster->boundary[nr + 1] - 1 - offset;
3118 else
3119 end = cluster->end - offset;
3120
3121 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3122 num_bytes = end + 1 - start;
3123 if (cur_offset < start)
3124 btrfs_free_reserved_data_space(inode, data_reserved,
3125 cur_offset, start - cur_offset);
3126 ret = btrfs_prealloc_file_range(inode, 0, start,
3127 num_bytes, num_bytes,
3128 end + 1, &alloc_hint);
3129 cur_offset = end + 1;
3130 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3131 if (ret)
3132 break;
3133 nr++;
3134 }
3135 if (cur_offset < prealloc_end)
3136 btrfs_free_reserved_data_space(inode, data_reserved,
3137 cur_offset, prealloc_end + 1 - cur_offset);
3138 out:
3139 inode_unlock(inode);
3140 extent_changeset_free(data_reserved);
3141 return ret;
3142 }
3143
3144 static noinline_for_stack
3145 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3146 u64 block_start)
3147 {
3148 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3149 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3150 struct extent_map *em;
3151 int ret = 0;
3152
3153 em = alloc_extent_map();
3154 if (!em)
3155 return -ENOMEM;
3156
3157 em->start = start;
3158 em->len = end + 1 - start;
3159 em->block_len = em->len;
3160 em->block_start = block_start;
3161 em->bdev = fs_info->fs_devices->latest_bdev;
3162 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3163
3164 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3165 while (1) {
3166 write_lock(&em_tree->lock);
3167 ret = add_extent_mapping(em_tree, em, 0);
3168 write_unlock(&em_tree->lock);
3169 if (ret != -EEXIST) {
3170 free_extent_map(em);
3171 break;
3172 }
3173 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3174 }
3175 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3176 return ret;
3177 }
3178
3179 static int relocate_file_extent_cluster(struct inode *inode,
3180 struct file_extent_cluster *cluster)
3181 {
3182 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3183 u64 page_start;
3184 u64 page_end;
3185 u64 offset = BTRFS_I(inode)->index_cnt;
3186 unsigned long index;
3187 unsigned long last_index;
3188 struct page *page;
3189 struct file_ra_state *ra;
3190 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3191 int nr = 0;
3192 int ret = 0;
3193
3194 if (!cluster->nr)
3195 return 0;
3196
3197 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3198 if (!ra)
3199 return -ENOMEM;
3200
3201 ret = prealloc_file_extent_cluster(inode, cluster);
3202 if (ret)
3203 goto out;
3204
3205 file_ra_state_init(ra, inode->i_mapping);
3206
3207 ret = setup_extent_mapping(inode, cluster->start - offset,
3208 cluster->end - offset, cluster->start);
3209 if (ret)
3210 goto out;
3211
3212 index = (cluster->start - offset) >> PAGE_SHIFT;
3213 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3214 while (index <= last_index) {
3215 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3216 PAGE_SIZE);
3217 if (ret)
3218 goto out;
3219
3220 page = find_lock_page(inode->i_mapping, index);
3221 if (!page) {
3222 page_cache_sync_readahead(inode->i_mapping,
3223 ra, NULL, index,
3224 last_index + 1 - index);
3225 page = find_or_create_page(inode->i_mapping, index,
3226 mask);
3227 if (!page) {
3228 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3229 PAGE_SIZE, true);
3230 ret = -ENOMEM;
3231 goto out;
3232 }
3233 }
3234
3235 if (PageReadahead(page)) {
3236 page_cache_async_readahead(inode->i_mapping,
3237 ra, NULL, page, index,
3238 last_index + 1 - index);
3239 }
3240
3241 if (!PageUptodate(page)) {
3242 btrfs_readpage(NULL, page);
3243 lock_page(page);
3244 if (!PageUptodate(page)) {
3245 unlock_page(page);
3246 put_page(page);
3247 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3248 PAGE_SIZE, true);
3249 btrfs_delalloc_release_extents(BTRFS_I(inode),
3250 PAGE_SIZE, true);
3251 ret = -EIO;
3252 goto out;
3253 }
3254 }
3255
3256 page_start = page_offset(page);
3257 page_end = page_start + PAGE_SIZE - 1;
3258
3259 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3260
3261 set_page_extent_mapped(page);
3262
3263 if (nr < cluster->nr &&
3264 page_start + offset == cluster->boundary[nr]) {
3265 set_extent_bits(&BTRFS_I(inode)->io_tree,
3266 page_start, page_end,
3267 EXTENT_BOUNDARY);
3268 nr++;
3269 }
3270
3271 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3272 NULL, 0);
3273 if (ret) {
3274 unlock_page(page);
3275 put_page(page);
3276 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3277 PAGE_SIZE, true);
3278 btrfs_delalloc_release_extents(BTRFS_I(inode),
3279 PAGE_SIZE, true);
3280
3281 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3282 page_start, page_end,
3283 EXTENT_LOCKED | EXTENT_BOUNDARY);
3284 goto out;
3285
3286 }
3287 set_page_dirty(page);
3288
3289 unlock_extent(&BTRFS_I(inode)->io_tree,
3290 page_start, page_end);
3291 unlock_page(page);
3292 put_page(page);
3293
3294 index++;
3295 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3296 false);
3297 balance_dirty_pages_ratelimited(inode->i_mapping);
3298 btrfs_throttle(fs_info);
3299 }
3300 WARN_ON(nr != cluster->nr);
3301 out:
3302 kfree(ra);
3303 return ret;
3304 }
3305
3306 static noinline_for_stack
3307 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3308 struct file_extent_cluster *cluster)
3309 {
3310 int ret;
3311
3312 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3313 ret = relocate_file_extent_cluster(inode, cluster);
3314 if (ret)
3315 return ret;
3316 cluster->nr = 0;
3317 }
3318
3319 if (!cluster->nr)
3320 cluster->start = extent_key->objectid;
3321 else
3322 BUG_ON(cluster->nr >= MAX_EXTENTS);
3323 cluster->end = extent_key->objectid + extent_key->offset - 1;
3324 cluster->boundary[cluster->nr] = extent_key->objectid;
3325 cluster->nr++;
3326
3327 if (cluster->nr >= MAX_EXTENTS) {
3328 ret = relocate_file_extent_cluster(inode, cluster);
3329 if (ret)
3330 return ret;
3331 cluster->nr = 0;
3332 }
3333 return 0;
3334 }
3335
3336 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3337 static int get_ref_objectid_v0(struct reloc_control *rc,
3338 struct btrfs_path *path,
3339 struct btrfs_key *extent_key,
3340 u64 *ref_objectid, int *path_change)
3341 {
3342 struct btrfs_key key;
3343 struct extent_buffer *leaf;
3344 struct btrfs_extent_ref_v0 *ref0;
3345 int ret;
3346 int slot;
3347
3348 leaf = path->nodes[0];
3349 slot = path->slots[0];
3350 while (1) {
3351 if (slot >= btrfs_header_nritems(leaf)) {
3352 ret = btrfs_next_leaf(rc->extent_root, path);
3353 if (ret < 0)
3354 return ret;
3355 BUG_ON(ret > 0);
3356 leaf = path->nodes[0];
3357 slot = path->slots[0];
3358 if (path_change)
3359 *path_change = 1;
3360 }
3361 btrfs_item_key_to_cpu(leaf, &key, slot);
3362 if (key.objectid != extent_key->objectid)
3363 return -ENOENT;
3364
3365 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3366 slot++;
3367 continue;
3368 }
3369 ref0 = btrfs_item_ptr(leaf, slot,
3370 struct btrfs_extent_ref_v0);
3371 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3372 break;
3373 }
3374 return 0;
3375 }
3376 #endif
3377
3378 /*
3379 * helper to add a tree block to the list.
3380 * the major work is getting the generation and level of the block
3381 */
3382 static int add_tree_block(struct reloc_control *rc,
3383 struct btrfs_key *extent_key,
3384 struct btrfs_path *path,
3385 struct rb_root *blocks)
3386 {
3387 struct extent_buffer *eb;
3388 struct btrfs_extent_item *ei;
3389 struct btrfs_tree_block_info *bi;
3390 struct tree_block *block;
3391 struct rb_node *rb_node;
3392 u32 item_size;
3393 int level = -1;
3394 u64 generation;
3395
3396 eb = path->nodes[0];
3397 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3398
3399 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3400 item_size >= sizeof(*ei) + sizeof(*bi)) {
3401 ei = btrfs_item_ptr(eb, path->slots[0],
3402 struct btrfs_extent_item);
3403 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3404 bi = (struct btrfs_tree_block_info *)(ei + 1);
3405 level = btrfs_tree_block_level(eb, bi);
3406 } else {
3407 level = (int)extent_key->offset;
3408 }
3409 generation = btrfs_extent_generation(eb, ei);
3410 } else {
3411 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3412 u64 ref_owner;
3413 int ret;
3414
3415 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3416 ret = get_ref_objectid_v0(rc, path, extent_key,
3417 &ref_owner, NULL);
3418 if (ret < 0)
3419 return ret;
3420 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3421 level = (int)ref_owner;
3422 /* FIXME: get real generation */
3423 generation = 0;
3424 #else
3425 BUG();
3426 #endif
3427 }
3428
3429 btrfs_release_path(path);
3430
3431 BUG_ON(level == -1);
3432
3433 block = kmalloc(sizeof(*block), GFP_NOFS);
3434 if (!block)
3435 return -ENOMEM;
3436
3437 block->bytenr = extent_key->objectid;
3438 block->key.objectid = rc->extent_root->fs_info->nodesize;
3439 block->key.offset = generation;
3440 block->level = level;
3441 block->key_ready = 0;
3442
3443 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3444 if (rb_node)
3445 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3446
3447 return 0;
3448 }
3449
3450 /*
3451 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3452 */
3453 static int __add_tree_block(struct reloc_control *rc,
3454 u64 bytenr, u32 blocksize,
3455 struct rb_root *blocks)
3456 {
3457 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3458 struct btrfs_path *path;
3459 struct btrfs_key key;
3460 int ret;
3461 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3462
3463 if (tree_block_processed(bytenr, rc))
3464 return 0;
3465
3466 if (tree_search(blocks, bytenr))
3467 return 0;
3468
3469 path = btrfs_alloc_path();
3470 if (!path)
3471 return -ENOMEM;
3472 again:
3473 key.objectid = bytenr;
3474 if (skinny) {
3475 key.type = BTRFS_METADATA_ITEM_KEY;
3476 key.offset = (u64)-1;
3477 } else {
3478 key.type = BTRFS_EXTENT_ITEM_KEY;
3479 key.offset = blocksize;
3480 }
3481
3482 path->search_commit_root = 1;
3483 path->skip_locking = 1;
3484 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3485 if (ret < 0)
3486 goto out;
3487
3488 if (ret > 0 && skinny) {
3489 if (path->slots[0]) {
3490 path->slots[0]--;
3491 btrfs_item_key_to_cpu(path->nodes[0], &key,
3492 path->slots[0]);
3493 if (key.objectid == bytenr &&
3494 (key.type == BTRFS_METADATA_ITEM_KEY ||
3495 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3496 key.offset == blocksize)))
3497 ret = 0;
3498 }
3499
3500 if (ret) {
3501 skinny = false;
3502 btrfs_release_path(path);
3503 goto again;
3504 }
3505 }
3506 if (ret) {
3507 ASSERT(ret == 1);
3508 btrfs_print_leaf(path->nodes[0]);
3509 btrfs_err(fs_info,
3510 "tree block extent item (%llu) is not found in extent tree",
3511 bytenr);
3512 WARN_ON(1);
3513 ret = -EINVAL;
3514 goto out;
3515 }
3516
3517 ret = add_tree_block(rc, &key, path, blocks);
3518 out:
3519 btrfs_free_path(path);
3520 return ret;
3521 }
3522
3523 /*
3524 * helper to check if the block use full backrefs for pointers in it
3525 */
3526 static int block_use_full_backref(struct reloc_control *rc,
3527 struct extent_buffer *eb)
3528 {
3529 u64 flags;
3530 int ret;
3531
3532 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3533 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3534 return 1;
3535
3536 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3537 eb->start, btrfs_header_level(eb), 1,
3538 NULL, &flags);
3539 BUG_ON(ret);
3540
3541 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3542 ret = 1;
3543 else
3544 ret = 0;
3545 return ret;
3546 }
3547
3548 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3549 struct btrfs_block_group_cache *block_group,
3550 struct inode *inode,
3551 u64 ino)
3552 {
3553 struct btrfs_key key;
3554 struct btrfs_root *root = fs_info->tree_root;
3555 struct btrfs_trans_handle *trans;
3556 int ret = 0;
3557
3558 if (inode)
3559 goto truncate;
3560
3561 key.objectid = ino;
3562 key.type = BTRFS_INODE_ITEM_KEY;
3563 key.offset = 0;
3564
3565 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3566 if (IS_ERR(inode) || is_bad_inode(inode)) {
3567 if (!IS_ERR(inode))
3568 iput(inode);
3569 return -ENOENT;
3570 }
3571
3572 truncate:
3573 ret = btrfs_check_trunc_cache_free_space(fs_info,
3574 &fs_info->global_block_rsv);
3575 if (ret)
3576 goto out;
3577
3578 trans = btrfs_join_transaction(root);
3579 if (IS_ERR(trans)) {
3580 ret = PTR_ERR(trans);
3581 goto out;
3582 }
3583
3584 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3585
3586 btrfs_end_transaction(trans);
3587 btrfs_btree_balance_dirty(fs_info);
3588 out:
3589 iput(inode);
3590 return ret;
3591 }
3592
3593 /*
3594 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3595 * this function scans fs tree to find blocks reference the data extent
3596 */
3597 static int find_data_references(struct reloc_control *rc,
3598 struct btrfs_key *extent_key,
3599 struct extent_buffer *leaf,
3600 struct btrfs_extent_data_ref *ref,
3601 struct rb_root *blocks)
3602 {
3603 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3604 struct btrfs_path *path;
3605 struct tree_block *block;
3606 struct btrfs_root *root;
3607 struct btrfs_file_extent_item *fi;
3608 struct rb_node *rb_node;
3609 struct btrfs_key key;
3610 u64 ref_root;
3611 u64 ref_objectid;
3612 u64 ref_offset;
3613 u32 ref_count;
3614 u32 nritems;
3615 int err = 0;
3616 int added = 0;
3617 int counted;
3618 int ret;
3619
3620 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3621 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3622 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3623 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3624
3625 /*
3626 * This is an extent belonging to the free space cache, lets just delete
3627 * it and redo the search.
3628 */
3629 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3630 ret = delete_block_group_cache(fs_info, rc->block_group,
3631 NULL, ref_objectid);
3632 if (ret != -ENOENT)
3633 return ret;
3634 ret = 0;
3635 }
3636
3637 path = btrfs_alloc_path();
3638 if (!path)
3639 return -ENOMEM;
3640 path->reada = READA_FORWARD;
3641
3642 root = read_fs_root(fs_info, ref_root);
3643 if (IS_ERR(root)) {
3644 err = PTR_ERR(root);
3645 goto out;
3646 }
3647
3648 key.objectid = ref_objectid;
3649 key.type = BTRFS_EXTENT_DATA_KEY;
3650 if (ref_offset > ((u64)-1 << 32))
3651 key.offset = 0;
3652 else
3653 key.offset = ref_offset;
3654
3655 path->search_commit_root = 1;
3656 path->skip_locking = 1;
3657 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3658 if (ret < 0) {
3659 err = ret;
3660 goto out;
3661 }
3662
3663 leaf = path->nodes[0];
3664 nritems = btrfs_header_nritems(leaf);
3665 /*
3666 * the references in tree blocks that use full backrefs
3667 * are not counted in
3668 */
3669 if (block_use_full_backref(rc, leaf))
3670 counted = 0;
3671 else
3672 counted = 1;
3673 rb_node = tree_search(blocks, leaf->start);
3674 if (rb_node) {
3675 if (counted)
3676 added = 1;
3677 else
3678 path->slots[0] = nritems;
3679 }
3680
3681 while (ref_count > 0) {
3682 while (path->slots[0] >= nritems) {
3683 ret = btrfs_next_leaf(root, path);
3684 if (ret < 0) {
3685 err = ret;
3686 goto out;
3687 }
3688 if (WARN_ON(ret > 0))
3689 goto out;
3690
3691 leaf = path->nodes[0];
3692 nritems = btrfs_header_nritems(leaf);
3693 added = 0;
3694
3695 if (block_use_full_backref(rc, leaf))
3696 counted = 0;
3697 else
3698 counted = 1;
3699 rb_node = tree_search(blocks, leaf->start);
3700 if (rb_node) {
3701 if (counted)
3702 added = 1;
3703 else
3704 path->slots[0] = nritems;
3705 }
3706 }
3707
3708 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3709 if (WARN_ON(key.objectid != ref_objectid ||
3710 key.type != BTRFS_EXTENT_DATA_KEY))
3711 break;
3712
3713 fi = btrfs_item_ptr(leaf, path->slots[0],
3714 struct btrfs_file_extent_item);
3715
3716 if (btrfs_file_extent_type(leaf, fi) ==
3717 BTRFS_FILE_EXTENT_INLINE)
3718 goto next;
3719
3720 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3721 extent_key->objectid)
3722 goto next;
3723
3724 key.offset -= btrfs_file_extent_offset(leaf, fi);
3725 if (key.offset != ref_offset)
3726 goto next;
3727
3728 if (counted)
3729 ref_count--;
3730 if (added)
3731 goto next;
3732
3733 if (!tree_block_processed(leaf->start, rc)) {
3734 block = kmalloc(sizeof(*block), GFP_NOFS);
3735 if (!block) {
3736 err = -ENOMEM;
3737 break;
3738 }
3739 block->bytenr = leaf->start;
3740 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3741 block->level = 0;
3742 block->key_ready = 1;
3743 rb_node = tree_insert(blocks, block->bytenr,
3744 &block->rb_node);
3745 if (rb_node)
3746 backref_tree_panic(rb_node, -EEXIST,
3747 block->bytenr);
3748 }
3749 if (counted)
3750 added = 1;
3751 else
3752 path->slots[0] = nritems;
3753 next:
3754 path->slots[0]++;
3755
3756 }
3757 out:
3758 btrfs_free_path(path);
3759 return err;
3760 }
3761
3762 /*
3763 * helper to find all tree blocks that reference a given data extent
3764 */
3765 static noinline_for_stack
3766 int add_data_references(struct reloc_control *rc,
3767 struct btrfs_key *extent_key,
3768 struct btrfs_path *path,
3769 struct rb_root *blocks)
3770 {
3771 struct btrfs_key key;
3772 struct extent_buffer *eb;
3773 struct btrfs_extent_data_ref *dref;
3774 struct btrfs_extent_inline_ref *iref;
3775 unsigned long ptr;
3776 unsigned long end;
3777 u32 blocksize = rc->extent_root->fs_info->nodesize;
3778 int ret = 0;
3779 int err = 0;
3780
3781 eb = path->nodes[0];
3782 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3783 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3784 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3785 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3786 ptr = end;
3787 else
3788 #endif
3789 ptr += sizeof(struct btrfs_extent_item);
3790
3791 while (ptr < end) {
3792 iref = (struct btrfs_extent_inline_ref *)ptr;
3793 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3794 BTRFS_REF_TYPE_DATA);
3795 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3796 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3797 ret = __add_tree_block(rc, key.offset, blocksize,
3798 blocks);
3799 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3800 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3801 ret = find_data_references(rc, extent_key,
3802 eb, dref, blocks);
3803 } else {
3804 ret = -EINVAL;
3805 btrfs_err(rc->extent_root->fs_info,
3806 "extent %llu slot %d has an invalid inline ref type",
3807 eb->start, path->slots[0]);
3808 }
3809 if (ret) {
3810 err = ret;
3811 goto out;
3812 }
3813 ptr += btrfs_extent_inline_ref_size(key.type);
3814 }
3815 WARN_ON(ptr > end);
3816
3817 while (1) {
3818 cond_resched();
3819 eb = path->nodes[0];
3820 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3821 ret = btrfs_next_leaf(rc->extent_root, path);
3822 if (ret < 0) {
3823 err = ret;
3824 break;
3825 }
3826 if (ret > 0)
3827 break;
3828 eb = path->nodes[0];
3829 }
3830
3831 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3832 if (key.objectid != extent_key->objectid)
3833 break;
3834
3835 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3836 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3837 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3838 #else
3839 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3840 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3841 #endif
3842 ret = __add_tree_block(rc, key.offset, blocksize,
3843 blocks);
3844 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3845 dref = btrfs_item_ptr(eb, path->slots[0],
3846 struct btrfs_extent_data_ref);
3847 ret = find_data_references(rc, extent_key,
3848 eb, dref, blocks);
3849 } else {
3850 ret = 0;
3851 }
3852 if (ret) {
3853 err = ret;
3854 break;
3855 }
3856 path->slots[0]++;
3857 }
3858 out:
3859 btrfs_release_path(path);
3860 if (err)
3861 free_block_list(blocks);
3862 return err;
3863 }
3864
3865 /*
3866 * helper to find next unprocessed extent
3867 */
3868 static noinline_for_stack
3869 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3870 struct btrfs_key *extent_key)
3871 {
3872 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3873 struct btrfs_key key;
3874 struct extent_buffer *leaf;
3875 u64 start, end, last;
3876 int ret;
3877
3878 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3879 while (1) {
3880 cond_resched();
3881 if (rc->search_start >= last) {
3882 ret = 1;
3883 break;
3884 }
3885
3886 key.objectid = rc->search_start;
3887 key.type = BTRFS_EXTENT_ITEM_KEY;
3888 key.offset = 0;
3889
3890 path->search_commit_root = 1;
3891 path->skip_locking = 1;
3892 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3893 0, 0);
3894 if (ret < 0)
3895 break;
3896 next:
3897 leaf = path->nodes[0];
3898 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3899 ret = btrfs_next_leaf(rc->extent_root, path);
3900 if (ret != 0)
3901 break;
3902 leaf = path->nodes[0];
3903 }
3904
3905 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3906 if (key.objectid >= last) {
3907 ret = 1;
3908 break;
3909 }
3910
3911 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3912 key.type != BTRFS_METADATA_ITEM_KEY) {
3913 path->slots[0]++;
3914 goto next;
3915 }
3916
3917 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3918 key.objectid + key.offset <= rc->search_start) {
3919 path->slots[0]++;
3920 goto next;
3921 }
3922
3923 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3924 key.objectid + fs_info->nodesize <=
3925 rc->search_start) {
3926 path->slots[0]++;
3927 goto next;
3928 }
3929
3930 ret = find_first_extent_bit(&rc->processed_blocks,
3931 key.objectid, &start, &end,
3932 EXTENT_DIRTY, NULL);
3933
3934 if (ret == 0 && start <= key.objectid) {
3935 btrfs_release_path(path);
3936 rc->search_start = end + 1;
3937 } else {
3938 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3939 rc->search_start = key.objectid + key.offset;
3940 else
3941 rc->search_start = key.objectid +
3942 fs_info->nodesize;
3943 memcpy(extent_key, &key, sizeof(key));
3944 return 0;
3945 }
3946 }
3947 btrfs_release_path(path);
3948 return ret;
3949 }
3950
3951 static void set_reloc_control(struct reloc_control *rc)
3952 {
3953 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3954
3955 mutex_lock(&fs_info->reloc_mutex);
3956 fs_info->reloc_ctl = rc;
3957 mutex_unlock(&fs_info->reloc_mutex);
3958 }
3959
3960 static void unset_reloc_control(struct reloc_control *rc)
3961 {
3962 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3963
3964 mutex_lock(&fs_info->reloc_mutex);
3965 fs_info->reloc_ctl = NULL;
3966 mutex_unlock(&fs_info->reloc_mutex);
3967 }
3968
3969 static int check_extent_flags(u64 flags)
3970 {
3971 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3972 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3973 return 1;
3974 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3975 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3976 return 1;
3977 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3978 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3979 return 1;
3980 return 0;
3981 }
3982
3983 static noinline_for_stack
3984 int prepare_to_relocate(struct reloc_control *rc)
3985 {
3986 struct btrfs_trans_handle *trans;
3987 int ret;
3988
3989 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3990 BTRFS_BLOCK_RSV_TEMP);
3991 if (!rc->block_rsv)
3992 return -ENOMEM;
3993
3994 memset(&rc->cluster, 0, sizeof(rc->cluster));
3995 rc->search_start = rc->block_group->key.objectid;
3996 rc->extents_found = 0;
3997 rc->nodes_relocated = 0;
3998 rc->merging_rsv_size = 0;
3999 rc->reserved_bytes = 0;
4000 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
4001 RELOCATION_RESERVED_NODES;
4002 ret = btrfs_block_rsv_refill(rc->extent_root,
4003 rc->block_rsv, rc->block_rsv->size,
4004 BTRFS_RESERVE_FLUSH_ALL);
4005 if (ret)
4006 return ret;
4007
4008 rc->create_reloc_tree = 1;
4009 set_reloc_control(rc);
4010
4011 trans = btrfs_join_transaction(rc->extent_root);
4012 if (IS_ERR(trans)) {
4013 unset_reloc_control(rc);
4014 /*
4015 * extent tree is not a ref_cow tree and has no reloc_root to
4016 * cleanup. And callers are responsible to free the above
4017 * block rsv.
4018 */
4019 return PTR_ERR(trans);
4020 }
4021 btrfs_commit_transaction(trans);
4022 return 0;
4023 }
4024
4025 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4026 {
4027 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4028 struct rb_root blocks = RB_ROOT;
4029 struct btrfs_key key;
4030 struct btrfs_trans_handle *trans = NULL;
4031 struct btrfs_path *path;
4032 struct btrfs_extent_item *ei;
4033 u64 flags;
4034 u32 item_size;
4035 int ret;
4036 int err = 0;
4037 int progress = 0;
4038
4039 path = btrfs_alloc_path();
4040 if (!path)
4041 return -ENOMEM;
4042 path->reada = READA_FORWARD;
4043
4044 ret = prepare_to_relocate(rc);
4045 if (ret) {
4046 err = ret;
4047 goto out_free;
4048 }
4049
4050 while (1) {
4051 rc->reserved_bytes = 0;
4052 ret = btrfs_block_rsv_refill(rc->extent_root,
4053 rc->block_rsv, rc->block_rsv->size,
4054 BTRFS_RESERVE_FLUSH_ALL);
4055 if (ret) {
4056 err = ret;
4057 break;
4058 }
4059 progress++;
4060 trans = btrfs_start_transaction(rc->extent_root, 0);
4061 if (IS_ERR(trans)) {
4062 err = PTR_ERR(trans);
4063 trans = NULL;
4064 break;
4065 }
4066 restart:
4067 if (update_backref_cache(trans, &rc->backref_cache)) {
4068 btrfs_end_transaction(trans);
4069 continue;
4070 }
4071
4072 ret = find_next_extent(rc, path, &key);
4073 if (ret < 0)
4074 err = ret;
4075 if (ret != 0)
4076 break;
4077
4078 rc->extents_found++;
4079
4080 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4081 struct btrfs_extent_item);
4082 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4083 if (item_size >= sizeof(*ei)) {
4084 flags = btrfs_extent_flags(path->nodes[0], ei);
4085 ret = check_extent_flags(flags);
4086 BUG_ON(ret);
4087
4088 } else {
4089 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4090 u64 ref_owner;
4091 int path_change = 0;
4092
4093 BUG_ON(item_size !=
4094 sizeof(struct btrfs_extent_item_v0));
4095 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4096 &path_change);
4097 if (ret < 0) {
4098 err = ret;
4099 break;
4100 }
4101 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4102 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4103 else
4104 flags = BTRFS_EXTENT_FLAG_DATA;
4105
4106 if (path_change) {
4107 btrfs_release_path(path);
4108
4109 path->search_commit_root = 1;
4110 path->skip_locking = 1;
4111 ret = btrfs_search_slot(NULL, rc->extent_root,
4112 &key, path, 0, 0);
4113 if (ret < 0) {
4114 err = ret;
4115 break;
4116 }
4117 BUG_ON(ret > 0);
4118 }
4119 #else
4120 BUG();
4121 #endif
4122 }
4123
4124 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4125 ret = add_tree_block(rc, &key, path, &blocks);
4126 } else if (rc->stage == UPDATE_DATA_PTRS &&
4127 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4128 ret = add_data_references(rc, &key, path, &blocks);
4129 } else {
4130 btrfs_release_path(path);
4131 ret = 0;
4132 }
4133 if (ret < 0) {
4134 err = ret;
4135 break;
4136 }
4137
4138 if (!RB_EMPTY_ROOT(&blocks)) {
4139 ret = relocate_tree_blocks(trans, rc, &blocks);
4140 if (ret < 0) {
4141 /*
4142 * if we fail to relocate tree blocks, force to update
4143 * backref cache when committing transaction.
4144 */
4145 rc->backref_cache.last_trans = trans->transid - 1;
4146
4147 if (ret != -EAGAIN) {
4148 err = ret;
4149 break;
4150 }
4151 rc->extents_found--;
4152 rc->search_start = key.objectid;
4153 }
4154 }
4155
4156 btrfs_end_transaction_throttle(trans);
4157 btrfs_btree_balance_dirty(fs_info);
4158 trans = NULL;
4159
4160 if (rc->stage == MOVE_DATA_EXTENTS &&
4161 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4162 rc->found_file_extent = 1;
4163 ret = relocate_data_extent(rc->data_inode,
4164 &key, &rc->cluster);
4165 if (ret < 0) {
4166 err = ret;
4167 break;
4168 }
4169 }
4170 }
4171 if (trans && progress && err == -ENOSPC) {
4172 ret = btrfs_force_chunk_alloc(trans, fs_info,
4173 rc->block_group->flags);
4174 if (ret == 1) {
4175 err = 0;
4176 progress = 0;
4177 goto restart;
4178 }
4179 }
4180
4181 btrfs_release_path(path);
4182 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4183
4184 if (trans) {
4185 btrfs_end_transaction_throttle(trans);
4186 btrfs_btree_balance_dirty(fs_info);
4187 }
4188
4189 if (!err) {
4190 ret = relocate_file_extent_cluster(rc->data_inode,
4191 &rc->cluster);
4192 if (ret < 0)
4193 err = ret;
4194 }
4195
4196 rc->create_reloc_tree = 0;
4197 set_reloc_control(rc);
4198
4199 backref_cache_cleanup(&rc->backref_cache);
4200 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4201
4202 err = prepare_to_merge(rc, err);
4203
4204 merge_reloc_roots(rc);
4205
4206 rc->merge_reloc_tree = 0;
4207 unset_reloc_control(rc);
4208 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4209
4210 /* get rid of pinned extents */
4211 trans = btrfs_join_transaction(rc->extent_root);
4212 if (IS_ERR(trans)) {
4213 err = PTR_ERR(trans);
4214 goto out_free;
4215 }
4216 btrfs_commit_transaction(trans);
4217 out_free:
4218 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4219 btrfs_free_path(path);
4220 return err;
4221 }
4222
4223 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4224 struct btrfs_root *root, u64 objectid)
4225 {
4226 struct btrfs_path *path;
4227 struct btrfs_inode_item *item;
4228 struct extent_buffer *leaf;
4229 int ret;
4230
4231 path = btrfs_alloc_path();
4232 if (!path)
4233 return -ENOMEM;
4234
4235 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4236 if (ret)
4237 goto out;
4238
4239 leaf = path->nodes[0];
4240 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4241 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4242 btrfs_set_inode_generation(leaf, item, 1);
4243 btrfs_set_inode_size(leaf, item, 0);
4244 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4245 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4246 BTRFS_INODE_PREALLOC);
4247 btrfs_mark_buffer_dirty(leaf);
4248 out:
4249 btrfs_free_path(path);
4250 return ret;
4251 }
4252
4253 /*
4254 * helper to create inode for data relocation.
4255 * the inode is in data relocation tree and its link count is 0
4256 */
4257 static noinline_for_stack
4258 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4259 struct btrfs_block_group_cache *group)
4260 {
4261 struct inode *inode = NULL;
4262 struct btrfs_trans_handle *trans;
4263 struct btrfs_root *root;
4264 struct btrfs_key key;
4265 u64 objectid;
4266 int err = 0;
4267
4268 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4269 if (IS_ERR(root))
4270 return ERR_CAST(root);
4271
4272 trans = btrfs_start_transaction(root, 6);
4273 if (IS_ERR(trans))
4274 return ERR_CAST(trans);
4275
4276 err = btrfs_find_free_objectid(root, &objectid);
4277 if (err)
4278 goto out;
4279
4280 err = __insert_orphan_inode(trans, root, objectid);
4281 BUG_ON(err);
4282
4283 key.objectid = objectid;
4284 key.type = BTRFS_INODE_ITEM_KEY;
4285 key.offset = 0;
4286 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4287 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4288 BTRFS_I(inode)->index_cnt = group->key.objectid;
4289
4290 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4291 out:
4292 btrfs_end_transaction(trans);
4293 btrfs_btree_balance_dirty(fs_info);
4294 if (err) {
4295 if (inode)
4296 iput(inode);
4297 inode = ERR_PTR(err);
4298 }
4299 return inode;
4300 }
4301
4302 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4303 {
4304 struct reloc_control *rc;
4305
4306 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4307 if (!rc)
4308 return NULL;
4309
4310 INIT_LIST_HEAD(&rc->reloc_roots);
4311 backref_cache_init(&rc->backref_cache);
4312 mapping_tree_init(&rc->reloc_root_tree);
4313 extent_io_tree_init(&rc->processed_blocks, NULL);
4314 return rc;
4315 }
4316
4317 /*
4318 * Print the block group being relocated
4319 */
4320 static void describe_relocation(struct btrfs_fs_info *fs_info,
4321 struct btrfs_block_group_cache *block_group)
4322 {
4323 char buf[128]; /* prefixed by a '|' that'll be dropped */
4324 u64 flags = block_group->flags;
4325
4326 /* Shouldn't happen */
4327 if (!flags) {
4328 strcpy(buf, "|NONE");
4329 } else {
4330 char *bp = buf;
4331
4332 #define DESCRIBE_FLAG(f, d) \
4333 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4334 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4335 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4336 }
4337 DESCRIBE_FLAG(DATA, "data");
4338 DESCRIBE_FLAG(SYSTEM, "system");
4339 DESCRIBE_FLAG(METADATA, "metadata");
4340 DESCRIBE_FLAG(RAID0, "raid0");
4341 DESCRIBE_FLAG(RAID1, "raid1");
4342 DESCRIBE_FLAG(DUP, "dup");
4343 DESCRIBE_FLAG(RAID10, "raid10");
4344 DESCRIBE_FLAG(RAID5, "raid5");
4345 DESCRIBE_FLAG(RAID6, "raid6");
4346 if (flags)
4347 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4348 #undef DESCRIBE_FLAG
4349 }
4350
4351 btrfs_info(fs_info,
4352 "relocating block group %llu flags %s",
4353 block_group->key.objectid, buf + 1);
4354 }
4355
4356 /*
4357 * function to relocate all extents in a block group.
4358 */
4359 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4360 {
4361 struct btrfs_root *extent_root = fs_info->extent_root;
4362 struct reloc_control *rc;
4363 struct inode *inode;
4364 struct btrfs_path *path;
4365 int ret;
4366 int rw = 0;
4367 int err = 0;
4368
4369 rc = alloc_reloc_control(fs_info);
4370 if (!rc)
4371 return -ENOMEM;
4372
4373 rc->extent_root = extent_root;
4374
4375 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4376 BUG_ON(!rc->block_group);
4377
4378 ret = btrfs_inc_block_group_ro(fs_info, rc->block_group);
4379 if (ret) {
4380 err = ret;
4381 goto out;
4382 }
4383 rw = 1;
4384
4385 path = btrfs_alloc_path();
4386 if (!path) {
4387 err = -ENOMEM;
4388 goto out;
4389 }
4390
4391 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4392 btrfs_free_path(path);
4393
4394 if (!IS_ERR(inode))
4395 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4396 else
4397 ret = PTR_ERR(inode);
4398
4399 if (ret && ret != -ENOENT) {
4400 err = ret;
4401 goto out;
4402 }
4403
4404 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4405 if (IS_ERR(rc->data_inode)) {
4406 err = PTR_ERR(rc->data_inode);
4407 rc->data_inode = NULL;
4408 goto out;
4409 }
4410
4411 describe_relocation(fs_info, rc->block_group);
4412
4413 btrfs_wait_block_group_reservations(rc->block_group);
4414 btrfs_wait_nocow_writers(rc->block_group);
4415 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4416 rc->block_group->key.objectid,
4417 rc->block_group->key.offset);
4418
4419 while (1) {
4420 mutex_lock(&fs_info->cleaner_mutex);
4421 ret = relocate_block_group(rc);
4422 mutex_unlock(&fs_info->cleaner_mutex);
4423 if (ret < 0) {
4424 err = ret;
4425 goto out;
4426 }
4427
4428 if (rc->extents_found == 0)
4429 break;
4430
4431 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4432
4433 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4434 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4435 (u64)-1);
4436 if (ret) {
4437 err = ret;
4438 goto out;
4439 }
4440 invalidate_mapping_pages(rc->data_inode->i_mapping,
4441 0, -1);
4442 rc->stage = UPDATE_DATA_PTRS;
4443 }
4444 }
4445
4446 WARN_ON(rc->block_group->pinned > 0);
4447 WARN_ON(rc->block_group->reserved > 0);
4448 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4449 out:
4450 if (err && rw)
4451 btrfs_dec_block_group_ro(rc->block_group);
4452 iput(rc->data_inode);
4453 btrfs_put_block_group(rc->block_group);
4454 kfree(rc);
4455 return err;
4456 }
4457
4458 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4459 {
4460 struct btrfs_fs_info *fs_info = root->fs_info;
4461 struct btrfs_trans_handle *trans;
4462 int ret, err;
4463
4464 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4465 if (IS_ERR(trans))
4466 return PTR_ERR(trans);
4467
4468 memset(&root->root_item.drop_progress, 0,
4469 sizeof(root->root_item.drop_progress));
4470 root->root_item.drop_level = 0;
4471 btrfs_set_root_refs(&root->root_item, 0);
4472 ret = btrfs_update_root(trans, fs_info->tree_root,
4473 &root->root_key, &root->root_item);
4474
4475 err = btrfs_end_transaction(trans);
4476 if (err)
4477 return err;
4478 return ret;
4479 }
4480
4481 /*
4482 * recover relocation interrupted by system crash.
4483 *
4484 * this function resumes merging reloc trees with corresponding fs trees.
4485 * this is important for keeping the sharing of tree blocks
4486 */
4487 int btrfs_recover_relocation(struct btrfs_root *root)
4488 {
4489 struct btrfs_fs_info *fs_info = root->fs_info;
4490 LIST_HEAD(reloc_roots);
4491 struct btrfs_key key;
4492 struct btrfs_root *fs_root;
4493 struct btrfs_root *reloc_root;
4494 struct btrfs_path *path;
4495 struct extent_buffer *leaf;
4496 struct reloc_control *rc = NULL;
4497 struct btrfs_trans_handle *trans;
4498 int ret;
4499 int err = 0;
4500
4501 path = btrfs_alloc_path();
4502 if (!path)
4503 return -ENOMEM;
4504 path->reada = READA_BACK;
4505
4506 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4507 key.type = BTRFS_ROOT_ITEM_KEY;
4508 key.offset = (u64)-1;
4509
4510 while (1) {
4511 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4512 path, 0, 0);
4513 if (ret < 0) {
4514 err = ret;
4515 goto out;
4516 }
4517 if (ret > 0) {
4518 if (path->slots[0] == 0)
4519 break;
4520 path->slots[0]--;
4521 }
4522 leaf = path->nodes[0];
4523 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4524 btrfs_release_path(path);
4525
4526 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4527 key.type != BTRFS_ROOT_ITEM_KEY)
4528 break;
4529
4530 reloc_root = btrfs_read_fs_root(root, &key);
4531 if (IS_ERR(reloc_root)) {
4532 err = PTR_ERR(reloc_root);
4533 goto out;
4534 }
4535
4536 list_add(&reloc_root->root_list, &reloc_roots);
4537
4538 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4539 fs_root = read_fs_root(fs_info,
4540 reloc_root->root_key.offset);
4541 if (IS_ERR(fs_root)) {
4542 ret = PTR_ERR(fs_root);
4543 if (ret != -ENOENT) {
4544 err = ret;
4545 goto out;
4546 }
4547 ret = mark_garbage_root(reloc_root);
4548 if (ret < 0) {
4549 err = ret;
4550 goto out;
4551 }
4552 }
4553 }
4554
4555 if (key.offset == 0)
4556 break;
4557
4558 key.offset--;
4559 }
4560 btrfs_release_path(path);
4561
4562 if (list_empty(&reloc_roots))
4563 goto out;
4564
4565 rc = alloc_reloc_control(fs_info);
4566 if (!rc) {
4567 err = -ENOMEM;
4568 goto out;
4569 }
4570
4571 rc->extent_root = fs_info->extent_root;
4572
4573 set_reloc_control(rc);
4574
4575 trans = btrfs_join_transaction(rc->extent_root);
4576 if (IS_ERR(trans)) {
4577 unset_reloc_control(rc);
4578 err = PTR_ERR(trans);
4579 goto out_free;
4580 }
4581
4582 rc->merge_reloc_tree = 1;
4583
4584 while (!list_empty(&reloc_roots)) {
4585 reloc_root = list_entry(reloc_roots.next,
4586 struct btrfs_root, root_list);
4587 list_del(&reloc_root->root_list);
4588
4589 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4590 list_add_tail(&reloc_root->root_list,
4591 &rc->reloc_roots);
4592 continue;
4593 }
4594
4595 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4596 if (IS_ERR(fs_root)) {
4597 err = PTR_ERR(fs_root);
4598 goto out_free;
4599 }
4600
4601 err = __add_reloc_root(reloc_root);
4602 BUG_ON(err < 0); /* -ENOMEM or logic error */
4603 fs_root->reloc_root = reloc_root;
4604 }
4605
4606 err = btrfs_commit_transaction(trans);
4607 if (err)
4608 goto out_free;
4609
4610 merge_reloc_roots(rc);
4611
4612 unset_reloc_control(rc);
4613
4614 trans = btrfs_join_transaction(rc->extent_root);
4615 if (IS_ERR(trans)) {
4616 err = PTR_ERR(trans);
4617 goto out_free;
4618 }
4619 err = btrfs_commit_transaction(trans);
4620 out_free:
4621 kfree(rc);
4622 out:
4623 if (!list_empty(&reloc_roots))
4624 free_reloc_roots(&reloc_roots);
4625
4626 btrfs_free_path(path);
4627
4628 if (err == 0) {
4629 /* cleanup orphan inode in data relocation tree */
4630 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4631 if (IS_ERR(fs_root))
4632 err = PTR_ERR(fs_root);
4633 else
4634 err = btrfs_orphan_cleanup(fs_root);
4635 }
4636 return err;
4637 }
4638
4639 /*
4640 * helper to add ordered checksum for data relocation.
4641 *
4642 * cloning checksum properly handles the nodatasum extents.
4643 * it also saves CPU time to re-calculate the checksum.
4644 */
4645 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4646 {
4647 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4648 struct btrfs_ordered_sum *sums;
4649 struct btrfs_ordered_extent *ordered;
4650 int ret;
4651 u64 disk_bytenr;
4652 u64 new_bytenr;
4653 LIST_HEAD(list);
4654
4655 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4656 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4657
4658 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4659 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4660 disk_bytenr + len - 1, &list, 0);
4661 if (ret)
4662 goto out;
4663
4664 while (!list_empty(&list)) {
4665 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4666 list_del_init(&sums->list);
4667
4668 /*
4669 * We need to offset the new_bytenr based on where the csum is.
4670 * We need to do this because we will read in entire prealloc
4671 * extents but we may have written to say the middle of the
4672 * prealloc extent, so we need to make sure the csum goes with
4673 * the right disk offset.
4674 *
4675 * We can do this because the data reloc inode refers strictly
4676 * to the on disk bytes, so we don't have to worry about
4677 * disk_len vs real len like with real inodes since it's all
4678 * disk length.
4679 */
4680 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4681 sums->bytenr = new_bytenr;
4682
4683 btrfs_add_ordered_sum(inode, ordered, sums);
4684 }
4685 out:
4686 btrfs_put_ordered_extent(ordered);
4687 return ret;
4688 }
4689
4690 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4691 struct btrfs_root *root, struct extent_buffer *buf,
4692 struct extent_buffer *cow)
4693 {
4694 struct btrfs_fs_info *fs_info = root->fs_info;
4695 struct reloc_control *rc;
4696 struct backref_node *node;
4697 int first_cow = 0;
4698 int level;
4699 int ret = 0;
4700
4701 rc = fs_info->reloc_ctl;
4702 if (!rc)
4703 return 0;
4704
4705 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4706 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4707
4708 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4709 if (buf == root->node)
4710 __update_reloc_root(root, cow->start);
4711 }
4712
4713 level = btrfs_header_level(buf);
4714 if (btrfs_header_generation(buf) <=
4715 btrfs_root_last_snapshot(&root->root_item))
4716 first_cow = 1;
4717
4718 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4719 rc->create_reloc_tree) {
4720 WARN_ON(!first_cow && level == 0);
4721
4722 node = rc->backref_cache.path[level];
4723 BUG_ON(node->bytenr != buf->start &&
4724 node->new_bytenr != buf->start);
4725
4726 drop_node_buffer(node);
4727 extent_buffer_get(cow);
4728 node->eb = cow;
4729 node->new_bytenr = cow->start;
4730
4731 if (!node->pending) {
4732 list_move_tail(&node->list,
4733 &rc->backref_cache.pending[level]);
4734 node->pending = 1;
4735 }
4736
4737 if (first_cow)
4738 __mark_block_processed(rc, node);
4739
4740 if (first_cow && level > 0)
4741 rc->nodes_relocated += buf->len;
4742 }
4743
4744 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4745 ret = replace_file_extents(trans, rc, root, cow);
4746 return ret;
4747 }
4748
4749 /*
4750 * called before creating snapshot. it calculates metadata reservation
4751 * required for relocating tree blocks in the snapshot
4752 */
4753 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4754 u64 *bytes_to_reserve)
4755 {
4756 struct btrfs_root *root;
4757 struct reloc_control *rc;
4758
4759 root = pending->root;
4760 if (!root->reloc_root)
4761 return;
4762
4763 rc = root->fs_info->reloc_ctl;
4764 if (!rc->merge_reloc_tree)
4765 return;
4766
4767 root = root->reloc_root;
4768 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4769 /*
4770 * relocation is in the stage of merging trees. the space
4771 * used by merging a reloc tree is twice the size of
4772 * relocated tree nodes in the worst case. half for cowing
4773 * the reloc tree, half for cowing the fs tree. the space
4774 * used by cowing the reloc tree will be freed after the
4775 * tree is dropped. if we create snapshot, cowing the fs
4776 * tree may use more space than it frees. so we need
4777 * reserve extra space.
4778 */
4779 *bytes_to_reserve += rc->nodes_relocated;
4780 }
4781
4782 /*
4783 * called after snapshot is created. migrate block reservation
4784 * and create reloc root for the newly created snapshot
4785 */
4786 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4787 struct btrfs_pending_snapshot *pending)
4788 {
4789 struct btrfs_root *root = pending->root;
4790 struct btrfs_root *reloc_root;
4791 struct btrfs_root *new_root;
4792 struct reloc_control *rc;
4793 int ret;
4794
4795 if (!root->reloc_root)
4796 return 0;
4797
4798 rc = root->fs_info->reloc_ctl;
4799 rc->merging_rsv_size += rc->nodes_relocated;
4800
4801 if (rc->merge_reloc_tree) {
4802 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4803 rc->block_rsv,
4804 rc->nodes_relocated, 1);
4805 if (ret)
4806 return ret;
4807 }
4808
4809 new_root = pending->snap;
4810 reloc_root = create_reloc_root(trans, root->reloc_root,
4811 new_root->root_key.objectid);
4812 if (IS_ERR(reloc_root))
4813 return PTR_ERR(reloc_root);
4814
4815 ret = __add_reloc_root(reloc_root);
4816 BUG_ON(ret < 0);
4817 new_root->reloc_root = reloc_root;
4818
4819 if (rc->create_reloc_tree)
4820 ret = clone_backref_node(trans, rc, root, reloc_root);
4821 return ret;
4822 }
Linux with added FPC-III support