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Merge tag 'for-4.19-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave...
[linux-2.6/btrfs-unstable.git] / fs / btrfs / relocation.c
blob8783a1776540fbb214a6d464858d9a9fb36be843
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 static noinline_for_stack
590 int find_inline_backref(struct extent_buffer *leaf, int slot,
591 unsigned long *ptr, unsigned long *end)
592 {
593 struct btrfs_key key;
594 struct btrfs_extent_item *ei;
595 struct btrfs_tree_block_info *bi;
596 u32 item_size;
597
598 btrfs_item_key_to_cpu(leaf, &key, slot);
599
600 item_size = btrfs_item_size_nr(leaf, slot);
601 if (item_size < sizeof(*ei)) {
602 btrfs_print_v0_err(leaf->fs_info);
603 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
604 return 1;
605 }
606 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
607 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
608 BTRFS_EXTENT_FLAG_TREE_BLOCK));
609
610 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
611 item_size <= sizeof(*ei) + sizeof(*bi)) {
612 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
613 return 1;
614 }
615 if (key.type == BTRFS_METADATA_ITEM_KEY &&
616 item_size <= sizeof(*ei)) {
617 WARN_ON(item_size < sizeof(*ei));
618 return 1;
619 }
620
621 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
622 bi = (struct btrfs_tree_block_info *)(ei + 1);
623 *ptr = (unsigned long)(bi + 1);
624 } else {
625 *ptr = (unsigned long)(ei + 1);
626 }
627 *end = (unsigned long)ei + item_size;
628 return 0;
629 }
630
631 /*
632 * build backref tree for a given tree block. root of the backref tree
633 * corresponds the tree block, leaves of the backref tree correspond
634 * roots of b-trees that reference the tree block.
635 *
636 * the basic idea of this function is check backrefs of a given block
637 * to find upper level blocks that reference the block, and then check
638 * backrefs of these upper level blocks recursively. the recursion stop
639 * when tree root is reached or backrefs for the block is cached.
640 *
641 * NOTE: if we find backrefs for a block are cached, we know backrefs
642 * for all upper level blocks that directly/indirectly reference the
643 * block are also cached.
644 */
645 static noinline_for_stack
646 struct backref_node *build_backref_tree(struct reloc_control *rc,
647 struct btrfs_key *node_key,
648 int level, u64 bytenr)
649 {
650 struct backref_cache *cache = &rc->backref_cache;
651 struct btrfs_path *path1;
652 struct btrfs_path *path2;
653 struct extent_buffer *eb;
654 struct btrfs_root *root;
655 struct backref_node *cur;
656 struct backref_node *upper;
657 struct backref_node *lower;
658 struct backref_node *node = NULL;
659 struct backref_node *exist = NULL;
660 struct backref_edge *edge;
661 struct rb_node *rb_node;
662 struct btrfs_key key;
663 unsigned long end;
664 unsigned long ptr;
665 LIST_HEAD(list);
666 LIST_HEAD(useless);
667 int cowonly;
668 int ret;
669 int err = 0;
670 bool need_check = true;
671
672 path1 = btrfs_alloc_path();
673 path2 = btrfs_alloc_path();
674 if (!path1 || !path2) {
675 err = -ENOMEM;
676 goto out;
677 }
678 path1->reada = READA_FORWARD;
679 path2->reada = READA_FORWARD;
680
681 node = alloc_backref_node(cache);
682 if (!node) {
683 err = -ENOMEM;
684 goto out;
685 }
686
687 node->bytenr = bytenr;
688 node->level = level;
689 node->lowest = 1;
690 cur = node;
691 again:
692 end = 0;
693 ptr = 0;
694 key.objectid = cur->bytenr;
695 key.type = BTRFS_METADATA_ITEM_KEY;
696 key.offset = (u64)-1;
697
698 path1->search_commit_root = 1;
699 path1->skip_locking = 1;
700 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
701 0, 0);
702 if (ret < 0) {
703 err = ret;
704 goto out;
705 }
706 ASSERT(ret);
707 ASSERT(path1->slots[0]);
708
709 path1->slots[0]--;
710
711 WARN_ON(cur->checked);
712 if (!list_empty(&cur->upper)) {
713 /*
714 * the backref was added previously when processing
715 * backref of type BTRFS_TREE_BLOCK_REF_KEY
716 */
717 ASSERT(list_is_singular(&cur->upper));
718 edge = list_entry(cur->upper.next, struct backref_edge,
719 list[LOWER]);
720 ASSERT(list_empty(&edge->list[UPPER]));
721 exist = edge->node[UPPER];
722 /*
723 * add the upper level block to pending list if we need
724 * check its backrefs
725 */
726 if (!exist->checked)
727 list_add_tail(&edge->list[UPPER], &list);
728 } else {
729 exist = NULL;
730 }
731
732 while (1) {
733 cond_resched();
734 eb = path1->nodes[0];
735
736 if (ptr >= end) {
737 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
738 ret = btrfs_next_leaf(rc->extent_root, path1);
739 if (ret < 0) {
740 err = ret;
741 goto out;
742 }
743 if (ret > 0)
744 break;
745 eb = path1->nodes[0];
746 }
747
748 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
749 if (key.objectid != cur->bytenr) {
750 WARN_ON(exist);
751 break;
752 }
753
754 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
755 key.type == BTRFS_METADATA_ITEM_KEY) {
756 ret = find_inline_backref(eb, path1->slots[0],
757 &ptr, &end);
758 if (ret)
759 goto next;
760 }
761 }
762
763 if (ptr < end) {
764 /* update key for inline back ref */
765 struct btrfs_extent_inline_ref *iref;
766 int type;
767 iref = (struct btrfs_extent_inline_ref *)ptr;
768 type = btrfs_get_extent_inline_ref_type(eb, iref,
769 BTRFS_REF_TYPE_BLOCK);
770 if (type == BTRFS_REF_TYPE_INVALID) {
771 err = -EUCLEAN;
772 goto out;
773 }
774 key.type = type;
775 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
776
777 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
778 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
779 }
780
781 if (exist &&
782 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
783 exist->owner == key.offset) ||
784 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
785 exist->bytenr == key.offset))) {
786 exist = NULL;
787 goto next;
788 }
789
790 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
791 if (key.objectid == key.offset) {
792 /*
793 * only root blocks of reloc trees use
794 * backref of this type.
795 */
796 root = find_reloc_root(rc, cur->bytenr);
797 ASSERT(root);
798 cur->root = root;
799 break;
800 }
801
802 edge = alloc_backref_edge(cache);
803 if (!edge) {
804 err = -ENOMEM;
805 goto out;
806 }
807 rb_node = tree_search(&cache->rb_root, key.offset);
808 if (!rb_node) {
809 upper = alloc_backref_node(cache);
810 if (!upper) {
811 free_backref_edge(cache, edge);
812 err = -ENOMEM;
813 goto out;
814 }
815 upper->bytenr = key.offset;
816 upper->level = cur->level + 1;
817 /*
818 * backrefs for the upper level block isn't
819 * cached, add the block to pending list
820 */
821 list_add_tail(&edge->list[UPPER], &list);
822 } else {
823 upper = rb_entry(rb_node, struct backref_node,
824 rb_node);
825 ASSERT(upper->checked);
826 INIT_LIST_HEAD(&edge->list[UPPER]);
827 }
828 list_add_tail(&edge->list[LOWER], &cur->upper);
829 edge->node[LOWER] = cur;
830 edge->node[UPPER] = upper;
831
832 goto next;
833 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
834 err = -EINVAL;
835 btrfs_print_v0_err(rc->extent_root->fs_info);
836 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
837 NULL);
838 goto out;
839 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
840 goto next;
841 }
842
843 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
844 root = read_fs_root(rc->extent_root->fs_info, key.offset);
845 if (IS_ERR(root)) {
846 err = PTR_ERR(root);
847 goto out;
848 }
849
850 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
851 cur->cowonly = 1;
852
853 if (btrfs_root_level(&root->root_item) == cur->level) {
854 /* tree root */
855 ASSERT(btrfs_root_bytenr(&root->root_item) ==
856 cur->bytenr);
857 if (should_ignore_root(root))
858 list_add(&cur->list, &useless);
859 else
860 cur->root = root;
861 break;
862 }
863
864 level = cur->level + 1;
865
866 /*
867 * searching the tree to find upper level blocks
868 * reference the block.
869 */
870 path2->search_commit_root = 1;
871 path2->skip_locking = 1;
872 path2->lowest_level = level;
873 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
874 path2->lowest_level = 0;
875 if (ret < 0) {
876 err = ret;
877 goto out;
878 }
879 if (ret > 0 && path2->slots[level] > 0)
880 path2->slots[level]--;
881
882 eb = path2->nodes[level];
883 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
884 cur->bytenr) {
885 btrfs_err(root->fs_info,
886 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
887 cur->bytenr, level - 1, root->objectid,
888 node_key->objectid, node_key->type,
889 node_key->offset);
890 err = -ENOENT;
891 goto out;
892 }
893 lower = cur;
894 need_check = true;
895 for (; level < BTRFS_MAX_LEVEL; level++) {
896 if (!path2->nodes[level]) {
897 ASSERT(btrfs_root_bytenr(&root->root_item) ==
898 lower->bytenr);
899 if (should_ignore_root(root))
900 list_add(&lower->list, &useless);
901 else
902 lower->root = root;
903 break;
904 }
905
906 edge = alloc_backref_edge(cache);
907 if (!edge) {
908 err = -ENOMEM;
909 goto out;
910 }
911
912 eb = path2->nodes[level];
913 rb_node = tree_search(&cache->rb_root, eb->start);
914 if (!rb_node) {
915 upper = alloc_backref_node(cache);
916 if (!upper) {
917 free_backref_edge(cache, edge);
918 err = -ENOMEM;
919 goto out;
920 }
921 upper->bytenr = eb->start;
922 upper->owner = btrfs_header_owner(eb);
923 upper->level = lower->level + 1;
924 if (!test_bit(BTRFS_ROOT_REF_COWS,
925 &root->state))
926 upper->cowonly = 1;
927
928 /*
929 * if we know the block isn't shared
930 * we can void checking its backrefs.
931 */
932 if (btrfs_block_can_be_shared(root, eb))
933 upper->checked = 0;
934 else
935 upper->checked = 1;
936
937 /*
938 * add the block to pending list if we
939 * need check its backrefs, we only do this once
940 * while walking up a tree as we will catch
941 * anything else later on.
942 */
943 if (!upper->checked && need_check) {
944 need_check = false;
945 list_add_tail(&edge->list[UPPER],
946 &list);
947 } else {
948 if (upper->checked)
949 need_check = true;
950 INIT_LIST_HEAD(&edge->list[UPPER]);
951 }
952 } else {
953 upper = rb_entry(rb_node, struct backref_node,
954 rb_node);
955 ASSERT(upper->checked);
956 INIT_LIST_HEAD(&edge->list[UPPER]);
957 if (!upper->owner)
958 upper->owner = btrfs_header_owner(eb);
959 }
960 list_add_tail(&edge->list[LOWER], &lower->upper);
961 edge->node[LOWER] = lower;
962 edge->node[UPPER] = upper;
963
964 if (rb_node)
965 break;
966 lower = upper;
967 upper = NULL;
968 }
969 btrfs_release_path(path2);
970 next:
971 if (ptr < end) {
972 ptr += btrfs_extent_inline_ref_size(key.type);
973 if (ptr >= end) {
974 WARN_ON(ptr > end);
975 ptr = 0;
976 end = 0;
977 }
978 }
979 if (ptr >= end)
980 path1->slots[0]++;
981 }
982 btrfs_release_path(path1);
983
984 cur->checked = 1;
985 WARN_ON(exist);
986
987 /* the pending list isn't empty, take the first block to process */
988 if (!list_empty(&list)) {
989 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
990 list_del_init(&edge->list[UPPER]);
991 cur = edge->node[UPPER];
992 goto again;
993 }
994
995 /*
996 * everything goes well, connect backref nodes and insert backref nodes
997 * into the cache.
998 */
999 ASSERT(node->checked);
1000 cowonly = node->cowonly;
1001 if (!cowonly) {
1002 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1003 &node->rb_node);
1004 if (rb_node)
1005 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1006 list_add_tail(&node->lower, &cache->leaves);
1007 }
1008
1009 list_for_each_entry(edge, &node->upper, list[LOWER])
1010 list_add_tail(&edge->list[UPPER], &list);
1011
1012 while (!list_empty(&list)) {
1013 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1014 list_del_init(&edge->list[UPPER]);
1015 upper = edge->node[UPPER];
1016 if (upper->detached) {
1017 list_del(&edge->list[LOWER]);
1018 lower = edge->node[LOWER];
1019 free_backref_edge(cache, edge);
1020 if (list_empty(&lower->upper))
1021 list_add(&lower->list, &useless);
1022 continue;
1023 }
1024
1025 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1026 if (upper->lowest) {
1027 list_del_init(&upper->lower);
1028 upper->lowest = 0;
1029 }
1030
1031 list_add_tail(&edge->list[UPPER], &upper->lower);
1032 continue;
1033 }
1034
1035 if (!upper->checked) {
1036 /*
1037 * Still want to blow up for developers since this is a
1038 * logic bug.
1039 */
1040 ASSERT(0);
1041 err = -EINVAL;
1042 goto out;
1043 }
1044 if (cowonly != upper->cowonly) {
1045 ASSERT(0);
1046 err = -EINVAL;
1047 goto out;
1048 }
1049
1050 if (!cowonly) {
1051 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1052 &upper->rb_node);
1053 if (rb_node)
1054 backref_tree_panic(rb_node, -EEXIST,
1055 upper->bytenr);
1056 }
1057
1058 list_add_tail(&edge->list[UPPER], &upper->lower);
1059
1060 list_for_each_entry(edge, &upper->upper, list[LOWER])
1061 list_add_tail(&edge->list[UPPER], &list);
1062 }
1063 /*
1064 * process useless backref nodes. backref nodes for tree leaves
1065 * are deleted from the cache. backref nodes for upper level
1066 * tree blocks are left in the cache to avoid unnecessary backref
1067 * lookup.
1068 */
1069 while (!list_empty(&useless)) {
1070 upper = list_entry(useless.next, struct backref_node, list);
1071 list_del_init(&upper->list);
1072 ASSERT(list_empty(&upper->upper));
1073 if (upper == node)
1074 node = NULL;
1075 if (upper->lowest) {
1076 list_del_init(&upper->lower);
1077 upper->lowest = 0;
1078 }
1079 while (!list_empty(&upper->lower)) {
1080 edge = list_entry(upper->lower.next,
1081 struct backref_edge, list[UPPER]);
1082 list_del(&edge->list[UPPER]);
1083 list_del(&edge->list[LOWER]);
1084 lower = edge->node[LOWER];
1085 free_backref_edge(cache, edge);
1086
1087 if (list_empty(&lower->upper))
1088 list_add(&lower->list, &useless);
1089 }
1090 __mark_block_processed(rc, upper);
1091 if (upper->level > 0) {
1092 list_add(&upper->list, &cache->detached);
1093 upper->detached = 1;
1094 } else {
1095 rb_erase(&upper->rb_node, &cache->rb_root);
1096 free_backref_node(cache, upper);
1097 }
1098 }
1099 out:
1100 btrfs_free_path(path1);
1101 btrfs_free_path(path2);
1102 if (err) {
1103 while (!list_empty(&useless)) {
1104 lower = list_entry(useless.next,
1105 struct backref_node, list);
1106 list_del_init(&lower->list);
1107 }
1108 while (!list_empty(&list)) {
1109 edge = list_first_entry(&list, struct backref_edge,
1110 list[UPPER]);
1111 list_del(&edge->list[UPPER]);
1112 list_del(&edge->list[LOWER]);
1113 lower = edge->node[LOWER];
1114 upper = edge->node[UPPER];
1115 free_backref_edge(cache, edge);
1116
1117 /*
1118 * Lower is no longer linked to any upper backref nodes
1119 * and isn't in the cache, we can free it ourselves.
1120 */
1121 if (list_empty(&lower->upper) &&
1122 RB_EMPTY_NODE(&lower->rb_node))
1123 list_add(&lower->list, &useless);
1124
1125 if (!RB_EMPTY_NODE(&upper->rb_node))
1126 continue;
1127
1128 /* Add this guy's upper edges to the list to process */
1129 list_for_each_entry(edge, &upper->upper, list[LOWER])
1130 list_add_tail(&edge->list[UPPER], &list);
1131 if (list_empty(&upper->upper))
1132 list_add(&upper->list, &useless);
1133 }
1134
1135 while (!list_empty(&useless)) {
1136 lower = list_entry(useless.next,
1137 struct backref_node, list);
1138 list_del_init(&lower->list);
1139 if (lower == node)
1140 node = NULL;
1141 free_backref_node(cache, lower);
1142 }
1143
1144 free_backref_node(cache, node);
1145 return ERR_PTR(err);
1146 }
1147 ASSERT(!node || !node->detached);
1148 return node;
1149 }
1150
1151 /*
1152 * helper to add backref node for the newly created snapshot.
1153 * the backref node is created by cloning backref node that
1154 * corresponds to root of source tree
1155 */
1156 static int clone_backref_node(struct btrfs_trans_handle *trans,
1157 struct reloc_control *rc,
1158 struct btrfs_root *src,
1159 struct btrfs_root *dest)
1160 {
1161 struct btrfs_root *reloc_root = src->reloc_root;
1162 struct backref_cache *cache = &rc->backref_cache;
1163 struct backref_node *node = NULL;
1164 struct backref_node *new_node;
1165 struct backref_edge *edge;
1166 struct backref_edge *new_edge;
1167 struct rb_node *rb_node;
1168
1169 if (cache->last_trans > 0)
1170 update_backref_cache(trans, cache);
1171
1172 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1173 if (rb_node) {
1174 node = rb_entry(rb_node, struct backref_node, rb_node);
1175 if (node->detached)
1176 node = NULL;
1177 else
1178 BUG_ON(node->new_bytenr != reloc_root->node->start);
1179 }
1180
1181 if (!node) {
1182 rb_node = tree_search(&cache->rb_root,
1183 reloc_root->commit_root->start);
1184 if (rb_node) {
1185 node = rb_entry(rb_node, struct backref_node,
1186 rb_node);
1187 BUG_ON(node->detached);
1188 }
1189 }
1190
1191 if (!node)
1192 return 0;
1193
1194 new_node = alloc_backref_node(cache);
1195 if (!new_node)
1196 return -ENOMEM;
1197
1198 new_node->bytenr = dest->node->start;
1199 new_node->level = node->level;
1200 new_node->lowest = node->lowest;
1201 new_node->checked = 1;
1202 new_node->root = dest;
1203
1204 if (!node->lowest) {
1205 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1206 new_edge = alloc_backref_edge(cache);
1207 if (!new_edge)
1208 goto fail;
1209
1210 new_edge->node[UPPER] = new_node;
1211 new_edge->node[LOWER] = edge->node[LOWER];
1212 list_add_tail(&new_edge->list[UPPER],
1213 &new_node->lower);
1214 }
1215 } else {
1216 list_add_tail(&new_node->lower, &cache->leaves);
1217 }
1218
1219 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1220 &new_node->rb_node);
1221 if (rb_node)
1222 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1223
1224 if (!new_node->lowest) {
1225 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1226 list_add_tail(&new_edge->list[LOWER],
1227 &new_edge->node[LOWER]->upper);
1228 }
1229 }
1230 return 0;
1231 fail:
1232 while (!list_empty(&new_node->lower)) {
1233 new_edge = list_entry(new_node->lower.next,
1234 struct backref_edge, list[UPPER]);
1235 list_del(&new_edge->list[UPPER]);
1236 free_backref_edge(cache, new_edge);
1237 }
1238 free_backref_node(cache, new_node);
1239 return -ENOMEM;
1240 }
1241
1242 /*
1243 * helper to add 'address of tree root -> reloc tree' mapping
1244 */
1245 static int __must_check __add_reloc_root(struct btrfs_root *root)
1246 {
1247 struct btrfs_fs_info *fs_info = root->fs_info;
1248 struct rb_node *rb_node;
1249 struct mapping_node *node;
1250 struct reloc_control *rc = fs_info->reloc_ctl;
1251
1252 node = kmalloc(sizeof(*node), GFP_NOFS);
1253 if (!node)
1254 return -ENOMEM;
1255
1256 node->bytenr = root->node->start;
1257 node->data = root;
1258
1259 spin_lock(&rc->reloc_root_tree.lock);
1260 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1261 node->bytenr, &node->rb_node);
1262 spin_unlock(&rc->reloc_root_tree.lock);
1263 if (rb_node) {
1264 btrfs_panic(fs_info, -EEXIST,
1265 "Duplicate root found for start=%llu while inserting into relocation tree",
1266 node->bytenr);
1267 }
1268
1269 list_add_tail(&root->root_list, &rc->reloc_roots);
1270 return 0;
1271 }
1272
1273 /*
1274 * helper to delete the 'address of tree root -> reloc tree'
1275 * mapping
1276 */
1277 static void __del_reloc_root(struct btrfs_root *root)
1278 {
1279 struct btrfs_fs_info *fs_info = root->fs_info;
1280 struct rb_node *rb_node;
1281 struct mapping_node *node = NULL;
1282 struct reloc_control *rc = fs_info->reloc_ctl;
1283
1284 if (rc) {
1285 spin_lock(&rc->reloc_root_tree.lock);
1286 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1287 root->node->start);
1288 if (rb_node) {
1289 node = rb_entry(rb_node, struct mapping_node, rb_node);
1290 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1291 }
1292 spin_unlock(&rc->reloc_root_tree.lock);
1293 if (!node)
1294 return;
1295 BUG_ON((struct btrfs_root *)node->data != root);
1296 }
1297
1298 spin_lock(&fs_info->trans_lock);
1299 list_del_init(&root->root_list);
1300 spin_unlock(&fs_info->trans_lock);
1301 kfree(node);
1302 }
1303
1304 /*
1305 * helper to update the 'address of tree root -> reloc tree'
1306 * mapping
1307 */
1308 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1309 {
1310 struct btrfs_fs_info *fs_info = root->fs_info;
1311 struct rb_node *rb_node;
1312 struct mapping_node *node = NULL;
1313 struct reloc_control *rc = fs_info->reloc_ctl;
1314
1315 spin_lock(&rc->reloc_root_tree.lock);
1316 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1317 root->node->start);
1318 if (rb_node) {
1319 node = rb_entry(rb_node, struct mapping_node, rb_node);
1320 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1321 }
1322 spin_unlock(&rc->reloc_root_tree.lock);
1323
1324 if (!node)
1325 return 0;
1326 BUG_ON((struct btrfs_root *)node->data != root);
1327
1328 spin_lock(&rc->reloc_root_tree.lock);
1329 node->bytenr = new_bytenr;
1330 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1331 node->bytenr, &node->rb_node);
1332 spin_unlock(&rc->reloc_root_tree.lock);
1333 if (rb_node)
1334 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1335 return 0;
1336 }
1337
1338 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1339 struct btrfs_root *root, u64 objectid)
1340 {
1341 struct btrfs_fs_info *fs_info = root->fs_info;
1342 struct btrfs_root *reloc_root;
1343 struct extent_buffer *eb;
1344 struct btrfs_root_item *root_item;
1345 struct btrfs_key root_key;
1346 int ret;
1347
1348 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1349 BUG_ON(!root_item);
1350
1351 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1352 root_key.type = BTRFS_ROOT_ITEM_KEY;
1353 root_key.offset = objectid;
1354
1355 if (root->root_key.objectid == objectid) {
1356 u64 commit_root_gen;
1357
1358 /* called by btrfs_init_reloc_root */
1359 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1360 BTRFS_TREE_RELOC_OBJECTID);
1361 BUG_ON(ret);
1362 /*
1363 * Set the last_snapshot field to the generation of the commit
1364 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1365 * correctly (returns true) when the relocation root is created
1366 * either inside the critical section of a transaction commit
1367 * (through transaction.c:qgroup_account_snapshot()) and when
1368 * it's created before the transaction commit is started.
1369 */
1370 commit_root_gen = btrfs_header_generation(root->commit_root);
1371 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1372 } else {
1373 /*
1374 * called by btrfs_reloc_post_snapshot_hook.
1375 * the source tree is a reloc tree, all tree blocks
1376 * modified after it was created have RELOC flag
1377 * set in their headers. so it's OK to not update
1378 * the 'last_snapshot'.
1379 */
1380 ret = btrfs_copy_root(trans, root, root->node, &eb,
1381 BTRFS_TREE_RELOC_OBJECTID);
1382 BUG_ON(ret);
1383 }
1384
1385 memcpy(root_item, &root->root_item, sizeof(*root_item));
1386 btrfs_set_root_bytenr(root_item, eb->start);
1387 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1388 btrfs_set_root_generation(root_item, trans->transid);
1389
1390 if (root->root_key.objectid == objectid) {
1391 btrfs_set_root_refs(root_item, 0);
1392 memset(&root_item->drop_progress, 0,
1393 sizeof(struct btrfs_disk_key));
1394 root_item->drop_level = 0;
1395 }
1396
1397 btrfs_tree_unlock(eb);
1398 free_extent_buffer(eb);
1399
1400 ret = btrfs_insert_root(trans, fs_info->tree_root,
1401 &root_key, root_item);
1402 BUG_ON(ret);
1403 kfree(root_item);
1404
1405 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1406 BUG_ON(IS_ERR(reloc_root));
1407 reloc_root->last_trans = trans->transid;
1408 return reloc_root;
1409 }
1410
1411 /*
1412 * create reloc tree for a given fs tree. reloc tree is just a
1413 * snapshot of the fs tree with special root objectid.
1414 */
1415 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1416 struct btrfs_root *root)
1417 {
1418 struct btrfs_fs_info *fs_info = root->fs_info;
1419 struct btrfs_root *reloc_root;
1420 struct reloc_control *rc = fs_info->reloc_ctl;
1421 struct btrfs_block_rsv *rsv;
1422 int clear_rsv = 0;
1423 int ret;
1424
1425 if (root->reloc_root) {
1426 reloc_root = root->reloc_root;
1427 reloc_root->last_trans = trans->transid;
1428 return 0;
1429 }
1430
1431 if (!rc || !rc->create_reloc_tree ||
1432 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1433 return 0;
1434
1435 if (!trans->reloc_reserved) {
1436 rsv = trans->block_rsv;
1437 trans->block_rsv = rc->block_rsv;
1438 clear_rsv = 1;
1439 }
1440 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1441 if (clear_rsv)
1442 trans->block_rsv = rsv;
1443
1444 ret = __add_reloc_root(reloc_root);
1445 BUG_ON(ret < 0);
1446 root->reloc_root = reloc_root;
1447 return 0;
1448 }
1449
1450 /*
1451 * update root item of reloc tree
1452 */
1453 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1454 struct btrfs_root *root)
1455 {
1456 struct btrfs_fs_info *fs_info = root->fs_info;
1457 struct btrfs_root *reloc_root;
1458 struct btrfs_root_item *root_item;
1459 int ret;
1460
1461 if (!root->reloc_root)
1462 goto out;
1463
1464 reloc_root = root->reloc_root;
1465 root_item = &reloc_root->root_item;
1466
1467 if (fs_info->reloc_ctl->merge_reloc_tree &&
1468 btrfs_root_refs(root_item) == 0) {
1469 root->reloc_root = NULL;
1470 __del_reloc_root(reloc_root);
1471 }
1472
1473 if (reloc_root->commit_root != reloc_root->node) {
1474 btrfs_set_root_node(root_item, reloc_root->node);
1475 free_extent_buffer(reloc_root->commit_root);
1476 reloc_root->commit_root = btrfs_root_node(reloc_root);
1477 }
1478
1479 ret = btrfs_update_root(trans, fs_info->tree_root,
1480 &reloc_root->root_key, root_item);
1481 BUG_ON(ret);
1482
1483 out:
1484 return 0;
1485 }
1486
1487 /*
1488 * helper to find first cached inode with inode number >= objectid
1489 * in a subvolume
1490 */
1491 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1492 {
1493 struct rb_node *node;
1494 struct rb_node *prev;
1495 struct btrfs_inode *entry;
1496 struct inode *inode;
1497
1498 spin_lock(&root->inode_lock);
1499 again:
1500 node = root->inode_tree.rb_node;
1501 prev = NULL;
1502 while (node) {
1503 prev = node;
1504 entry = rb_entry(node, struct btrfs_inode, rb_node);
1505
1506 if (objectid < btrfs_ino(entry))
1507 node = node->rb_left;
1508 else if (objectid > btrfs_ino(entry))
1509 node = node->rb_right;
1510 else
1511 break;
1512 }
1513 if (!node) {
1514 while (prev) {
1515 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1516 if (objectid <= btrfs_ino(entry)) {
1517 node = prev;
1518 break;
1519 }
1520 prev = rb_next(prev);
1521 }
1522 }
1523 while (node) {
1524 entry = rb_entry(node, struct btrfs_inode, rb_node);
1525 inode = igrab(&entry->vfs_inode);
1526 if (inode) {
1527 spin_unlock(&root->inode_lock);
1528 return inode;
1529 }
1530
1531 objectid = btrfs_ino(entry) + 1;
1532 if (cond_resched_lock(&root->inode_lock))
1533 goto again;
1534
1535 node = rb_next(node);
1536 }
1537 spin_unlock(&root->inode_lock);
1538 return NULL;
1539 }
1540
1541 static int in_block_group(u64 bytenr,
1542 struct btrfs_block_group_cache *block_group)
1543 {
1544 if (bytenr >= block_group->key.objectid &&
1545 bytenr < block_group->key.objectid + block_group->key.offset)
1546 return 1;
1547 return 0;
1548 }
1549
1550 /*
1551 * get new location of data
1552 */
1553 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1554 u64 bytenr, u64 num_bytes)
1555 {
1556 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1557 struct btrfs_path *path;
1558 struct btrfs_file_extent_item *fi;
1559 struct extent_buffer *leaf;
1560 int ret;
1561
1562 path = btrfs_alloc_path();
1563 if (!path)
1564 return -ENOMEM;
1565
1566 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1567 ret = btrfs_lookup_file_extent(NULL, root, path,
1568 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1569 if (ret < 0)
1570 goto out;
1571 if (ret > 0) {
1572 ret = -ENOENT;
1573 goto out;
1574 }
1575
1576 leaf = path->nodes[0];
1577 fi = btrfs_item_ptr(leaf, path->slots[0],
1578 struct btrfs_file_extent_item);
1579
1580 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1581 btrfs_file_extent_compression(leaf, fi) ||
1582 btrfs_file_extent_encryption(leaf, fi) ||
1583 btrfs_file_extent_other_encoding(leaf, fi));
1584
1585 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1586 ret = -EINVAL;
1587 goto out;
1588 }
1589
1590 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1591 ret = 0;
1592 out:
1593 btrfs_free_path(path);
1594 return ret;
1595 }
1596
1597 /*
1598 * update file extent items in the tree leaf to point to
1599 * the new locations.
1600 */
1601 static noinline_for_stack
1602 int replace_file_extents(struct btrfs_trans_handle *trans,
1603 struct reloc_control *rc,
1604 struct btrfs_root *root,
1605 struct extent_buffer *leaf)
1606 {
1607 struct btrfs_fs_info *fs_info = root->fs_info;
1608 struct btrfs_key key;
1609 struct btrfs_file_extent_item *fi;
1610 struct inode *inode = NULL;
1611 u64 parent;
1612 u64 bytenr;
1613 u64 new_bytenr = 0;
1614 u64 num_bytes;
1615 u64 end;
1616 u32 nritems;
1617 u32 i;
1618 int ret = 0;
1619 int first = 1;
1620 int dirty = 0;
1621
1622 if (rc->stage != UPDATE_DATA_PTRS)
1623 return 0;
1624
1625 /* reloc trees always use full backref */
1626 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1627 parent = leaf->start;
1628 else
1629 parent = 0;
1630
1631 nritems = btrfs_header_nritems(leaf);
1632 for (i = 0; i < nritems; i++) {
1633 cond_resched();
1634 btrfs_item_key_to_cpu(leaf, &key, i);
1635 if (key.type != BTRFS_EXTENT_DATA_KEY)
1636 continue;
1637 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1638 if (btrfs_file_extent_type(leaf, fi) ==
1639 BTRFS_FILE_EXTENT_INLINE)
1640 continue;
1641 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1642 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1643 if (bytenr == 0)
1644 continue;
1645 if (!in_block_group(bytenr, rc->block_group))
1646 continue;
1647
1648 /*
1649 * if we are modifying block in fs tree, wait for readpage
1650 * to complete and drop the extent cache
1651 */
1652 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1653 if (first) {
1654 inode = find_next_inode(root, key.objectid);
1655 first = 0;
1656 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1657 btrfs_add_delayed_iput(inode);
1658 inode = find_next_inode(root, key.objectid);
1659 }
1660 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1661 end = key.offset +
1662 btrfs_file_extent_num_bytes(leaf, fi);
1663 WARN_ON(!IS_ALIGNED(key.offset,
1664 fs_info->sectorsize));
1665 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1666 end--;
1667 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1668 key.offset, end);
1669 if (!ret)
1670 continue;
1671
1672 btrfs_drop_extent_cache(BTRFS_I(inode),
1673 key.offset, end, 1);
1674 unlock_extent(&BTRFS_I(inode)->io_tree,
1675 key.offset, end);
1676 }
1677 }
1678
1679 ret = get_new_location(rc->data_inode, &new_bytenr,
1680 bytenr, num_bytes);
1681 if (ret) {
1682 /*
1683 * Don't have to abort since we've not changed anything
1684 * in the file extent yet.
1685 */
1686 break;
1687 }
1688
1689 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1690 dirty = 1;
1691
1692 key.offset -= btrfs_file_extent_offset(leaf, fi);
1693 ret = btrfs_inc_extent_ref(trans, root, new_bytenr,
1694 num_bytes, parent,
1695 btrfs_header_owner(leaf),
1696 key.objectid, key.offset);
1697 if (ret) {
1698 btrfs_abort_transaction(trans, ret);
1699 break;
1700 }
1701
1702 ret = btrfs_free_extent(trans, root, bytenr, num_bytes,
1703 parent, btrfs_header_owner(leaf),
1704 key.objectid, key.offset);
1705 if (ret) {
1706 btrfs_abort_transaction(trans, ret);
1707 break;
1708 }
1709 }
1710 if (dirty)
1711 btrfs_mark_buffer_dirty(leaf);
1712 if (inode)
1713 btrfs_add_delayed_iput(inode);
1714 return ret;
1715 }
1716
1717 static noinline_for_stack
1718 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1719 struct btrfs_path *path, int level)
1720 {
1721 struct btrfs_disk_key key1;
1722 struct btrfs_disk_key key2;
1723 btrfs_node_key(eb, &key1, slot);
1724 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1725 return memcmp(&key1, &key2, sizeof(key1));
1726 }
1727
1728 /*
1729 * try to replace tree blocks in fs tree with the new blocks
1730 * in reloc tree. tree blocks haven't been modified since the
1731 * reloc tree was create can be replaced.
1732 *
1733 * if a block was replaced, level of the block + 1 is returned.
1734 * if no block got replaced, 0 is returned. if there are other
1735 * errors, a negative error number is returned.
1736 */
1737 static noinline_for_stack
1738 int replace_path(struct btrfs_trans_handle *trans,
1739 struct btrfs_root *dest, struct btrfs_root *src,
1740 struct btrfs_path *path, struct btrfs_key *next_key,
1741 int lowest_level, int max_level)
1742 {
1743 struct btrfs_fs_info *fs_info = dest->fs_info;
1744 struct extent_buffer *eb;
1745 struct extent_buffer *parent;
1746 struct btrfs_key key;
1747 u64 old_bytenr;
1748 u64 new_bytenr;
1749 u64 old_ptr_gen;
1750 u64 new_ptr_gen;
1751 u64 last_snapshot;
1752 u32 blocksize;
1753 int cow = 0;
1754 int level;
1755 int ret;
1756 int slot;
1757
1758 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1759 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1760
1761 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1762 again:
1763 slot = path->slots[lowest_level];
1764 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1765
1766 eb = btrfs_lock_root_node(dest);
1767 btrfs_set_lock_blocking(eb);
1768 level = btrfs_header_level(eb);
1769
1770 if (level < lowest_level) {
1771 btrfs_tree_unlock(eb);
1772 free_extent_buffer(eb);
1773 return 0;
1774 }
1775
1776 if (cow) {
1777 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1778 BUG_ON(ret);
1779 }
1780 btrfs_set_lock_blocking(eb);
1781
1782 if (next_key) {
1783 next_key->objectid = (u64)-1;
1784 next_key->type = (u8)-1;
1785 next_key->offset = (u64)-1;
1786 }
1787
1788 parent = eb;
1789 while (1) {
1790 struct btrfs_key first_key;
1791
1792 level = btrfs_header_level(parent);
1793 BUG_ON(level < lowest_level);
1794
1795 ret = btrfs_bin_search(parent, &key, level, &slot);
1796 if (ret && slot > 0)
1797 slot--;
1798
1799 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1800 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1801
1802 old_bytenr = btrfs_node_blockptr(parent, slot);
1803 blocksize = fs_info->nodesize;
1804 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1805 btrfs_node_key_to_cpu(parent, &first_key, slot);
1806
1807 if (level <= max_level) {
1808 eb = path->nodes[level];
1809 new_bytenr = btrfs_node_blockptr(eb,
1810 path->slots[level]);
1811 new_ptr_gen = btrfs_node_ptr_generation(eb,
1812 path->slots[level]);
1813 } else {
1814 new_bytenr = 0;
1815 new_ptr_gen = 0;
1816 }
1817
1818 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1819 ret = level;
1820 break;
1821 }
1822
1823 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1824 memcmp_node_keys(parent, slot, path, level)) {
1825 if (level <= lowest_level) {
1826 ret = 0;
1827 break;
1828 }
1829
1830 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1831 level - 1, &first_key);
1832 if (IS_ERR(eb)) {
1833 ret = PTR_ERR(eb);
1834 break;
1835 } else if (!extent_buffer_uptodate(eb)) {
1836 ret = -EIO;
1837 free_extent_buffer(eb);
1838 break;
1839 }
1840 btrfs_tree_lock(eb);
1841 if (cow) {
1842 ret = btrfs_cow_block(trans, dest, eb, parent,
1843 slot, &eb);
1844 BUG_ON(ret);
1845 }
1846 btrfs_set_lock_blocking(eb);
1847
1848 btrfs_tree_unlock(parent);
1849 free_extent_buffer(parent);
1850
1851 parent = eb;
1852 continue;
1853 }
1854
1855 if (!cow) {
1856 btrfs_tree_unlock(parent);
1857 free_extent_buffer(parent);
1858 cow = 1;
1859 goto again;
1860 }
1861
1862 btrfs_node_key_to_cpu(path->nodes[level], &key,
1863 path->slots[level]);
1864 btrfs_release_path(path);
1865
1866 path->lowest_level = level;
1867 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1868 path->lowest_level = 0;
1869 BUG_ON(ret);
1870
1871 /*
1872 * Info qgroup to trace both subtrees.
1873 *
1874 * We must trace both trees.
1875 * 1) Tree reloc subtree
1876 * If not traced, we will leak data numbers
1877 * 2) Fs subtree
1878 * If not traced, we will double count old data
1879 * and tree block numbers, if current trans doesn't free
1880 * data reloc tree inode.
1881 */
1882 ret = btrfs_qgroup_trace_subtree(trans, parent,
1883 btrfs_header_generation(parent),
1884 btrfs_header_level(parent));
1885 if (ret < 0)
1886 break;
1887 ret = btrfs_qgroup_trace_subtree(trans, path->nodes[level],
1888 btrfs_header_generation(path->nodes[level]),
1889 btrfs_header_level(path->nodes[level]));
1890 if (ret < 0)
1891 break;
1892
1893 /*
1894 * swap blocks in fs tree and reloc tree.
1895 */
1896 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1897 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1898 btrfs_mark_buffer_dirty(parent);
1899
1900 btrfs_set_node_blockptr(path->nodes[level],
1901 path->slots[level], old_bytenr);
1902 btrfs_set_node_ptr_generation(path->nodes[level],
1903 path->slots[level], old_ptr_gen);
1904 btrfs_mark_buffer_dirty(path->nodes[level]);
1905
1906 ret = btrfs_inc_extent_ref(trans, src, old_bytenr,
1907 blocksize, path->nodes[level]->start,
1908 src->root_key.objectid, level - 1, 0);
1909 BUG_ON(ret);
1910 ret = btrfs_inc_extent_ref(trans, dest, new_bytenr,
1911 blocksize, 0, dest->root_key.objectid,
1912 level - 1, 0);
1913 BUG_ON(ret);
1914
1915 ret = btrfs_free_extent(trans, src, new_bytenr, blocksize,
1916 path->nodes[level]->start,
1917 src->root_key.objectid, level - 1, 0);
1918 BUG_ON(ret);
1919
1920 ret = btrfs_free_extent(trans, dest, old_bytenr, blocksize,
1921 0, dest->root_key.objectid, level - 1,
1922 0);
1923 BUG_ON(ret);
1924
1925 btrfs_unlock_up_safe(path, 0);
1926
1927 ret = level;
1928 break;
1929 }
1930 btrfs_tree_unlock(parent);
1931 free_extent_buffer(parent);
1932 return ret;
1933 }
1934
1935 /*
1936 * helper to find next relocated block in reloc tree
1937 */
1938 static noinline_for_stack
1939 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1940 int *level)
1941 {
1942 struct extent_buffer *eb;
1943 int i;
1944 u64 last_snapshot;
1945 u32 nritems;
1946
1947 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1948
1949 for (i = 0; i < *level; i++) {
1950 free_extent_buffer(path->nodes[i]);
1951 path->nodes[i] = NULL;
1952 }
1953
1954 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1955 eb = path->nodes[i];
1956 nritems = btrfs_header_nritems(eb);
1957 while (path->slots[i] + 1 < nritems) {
1958 path->slots[i]++;
1959 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1960 last_snapshot)
1961 continue;
1962
1963 *level = i;
1964 return 0;
1965 }
1966 free_extent_buffer(path->nodes[i]);
1967 path->nodes[i] = NULL;
1968 }
1969 return 1;
1970 }
1971
1972 /*
1973 * walk down reloc tree to find relocated block of lowest level
1974 */
1975 static noinline_for_stack
1976 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1977 int *level)
1978 {
1979 struct btrfs_fs_info *fs_info = root->fs_info;
1980 struct extent_buffer *eb = NULL;
1981 int i;
1982 u64 bytenr;
1983 u64 ptr_gen = 0;
1984 u64 last_snapshot;
1985 u32 nritems;
1986
1987 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1988
1989 for (i = *level; i > 0; i--) {
1990 struct btrfs_key first_key;
1991
1992 eb = path->nodes[i];
1993 nritems = btrfs_header_nritems(eb);
1994 while (path->slots[i] < nritems) {
1995 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1996 if (ptr_gen > last_snapshot)
1997 break;
1998 path->slots[i]++;
1999 }
2000 if (path->slots[i] >= nritems) {
2001 if (i == *level)
2002 break;
2003 *level = i + 1;
2004 return 0;
2005 }
2006 if (i == 1) {
2007 *level = i;
2008 return 0;
2009 }
2010
2011 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2012 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2013 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2014 &first_key);
2015 if (IS_ERR(eb)) {
2016 return PTR_ERR(eb);
2017 } else if (!extent_buffer_uptodate(eb)) {
2018 free_extent_buffer(eb);
2019 return -EIO;
2020 }
2021 BUG_ON(btrfs_header_level(eb) != i - 1);
2022 path->nodes[i - 1] = eb;
2023 path->slots[i - 1] = 0;
2024 }
2025 return 1;
2026 }
2027
2028 /*
2029 * invalidate extent cache for file extents whose key in range of
2030 * [min_key, max_key)
2031 */
2032 static int invalidate_extent_cache(struct btrfs_root *root,
2033 struct btrfs_key *min_key,
2034 struct btrfs_key *max_key)
2035 {
2036 struct btrfs_fs_info *fs_info = root->fs_info;
2037 struct inode *inode = NULL;
2038 u64 objectid;
2039 u64 start, end;
2040 u64 ino;
2041
2042 objectid = min_key->objectid;
2043 while (1) {
2044 cond_resched();
2045 iput(inode);
2046
2047 if (objectid > max_key->objectid)
2048 break;
2049
2050 inode = find_next_inode(root, objectid);
2051 if (!inode)
2052 break;
2053 ino = btrfs_ino(BTRFS_I(inode));
2054
2055 if (ino > max_key->objectid) {
2056 iput(inode);
2057 break;
2058 }
2059
2060 objectid = ino + 1;
2061 if (!S_ISREG(inode->i_mode))
2062 continue;
2063
2064 if (unlikely(min_key->objectid == ino)) {
2065 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2066 continue;
2067 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2068 start = 0;
2069 else {
2070 start = min_key->offset;
2071 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2072 }
2073 } else {
2074 start = 0;
2075 }
2076
2077 if (unlikely(max_key->objectid == ino)) {
2078 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2079 continue;
2080 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2081 end = (u64)-1;
2082 } else {
2083 if (max_key->offset == 0)
2084 continue;
2085 end = max_key->offset;
2086 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2087 end--;
2088 }
2089 } else {
2090 end = (u64)-1;
2091 }
2092
2093 /* the lock_extent waits for readpage to complete */
2094 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2095 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2096 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2097 }
2098 return 0;
2099 }
2100
2101 static int find_next_key(struct btrfs_path *path, int level,
2102 struct btrfs_key *key)
2103
2104 {
2105 while (level < BTRFS_MAX_LEVEL) {
2106 if (!path->nodes[level])
2107 break;
2108 if (path->slots[level] + 1 <
2109 btrfs_header_nritems(path->nodes[level])) {
2110 btrfs_node_key_to_cpu(path->nodes[level], key,
2111 path->slots[level] + 1);
2112 return 0;
2113 }
2114 level++;
2115 }
2116 return 1;
2117 }
2118
2119 /*
2120 * merge the relocated tree blocks in reloc tree with corresponding
2121 * fs tree.
2122 */
2123 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2124 struct btrfs_root *root)
2125 {
2126 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2127 LIST_HEAD(inode_list);
2128 struct btrfs_key key;
2129 struct btrfs_key next_key;
2130 struct btrfs_trans_handle *trans = NULL;
2131 struct btrfs_root *reloc_root;
2132 struct btrfs_root_item *root_item;
2133 struct btrfs_path *path;
2134 struct extent_buffer *leaf;
2135 int level;
2136 int max_level;
2137 int replaced = 0;
2138 int ret;
2139 int err = 0;
2140 u32 min_reserved;
2141
2142 path = btrfs_alloc_path();
2143 if (!path)
2144 return -ENOMEM;
2145 path->reada = READA_FORWARD;
2146
2147 reloc_root = root->reloc_root;
2148 root_item = &reloc_root->root_item;
2149
2150 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2151 level = btrfs_root_level(root_item);
2152 extent_buffer_get(reloc_root->node);
2153 path->nodes[level] = reloc_root->node;
2154 path->slots[level] = 0;
2155 } else {
2156 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2157
2158 level = root_item->drop_level;
2159 BUG_ON(level == 0);
2160 path->lowest_level = level;
2161 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2162 path->lowest_level = 0;
2163 if (ret < 0) {
2164 btrfs_free_path(path);
2165 return ret;
2166 }
2167
2168 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2169 path->slots[level]);
2170 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2171
2172 btrfs_unlock_up_safe(path, 0);
2173 }
2174
2175 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2176 memset(&next_key, 0, sizeof(next_key));
2177
2178 while (1) {
2179 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2180 BTRFS_RESERVE_FLUSH_ALL);
2181 if (ret) {
2182 err = ret;
2183 goto out;
2184 }
2185 trans = btrfs_start_transaction(root, 0);
2186 if (IS_ERR(trans)) {
2187 err = PTR_ERR(trans);
2188 trans = NULL;
2189 goto out;
2190 }
2191 trans->block_rsv = rc->block_rsv;
2192
2193 replaced = 0;
2194 max_level = level;
2195
2196 ret = walk_down_reloc_tree(reloc_root, path, &level);
2197 if (ret < 0) {
2198 err = ret;
2199 goto out;
2200 }
2201 if (ret > 0)
2202 break;
2203
2204 if (!find_next_key(path, level, &key) &&
2205 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2206 ret = 0;
2207 } else {
2208 ret = replace_path(trans, root, reloc_root, path,
2209 &next_key, level, max_level);
2210 }
2211 if (ret < 0) {
2212 err = ret;
2213 goto out;
2214 }
2215
2216 if (ret > 0) {
2217 level = ret;
2218 btrfs_node_key_to_cpu(path->nodes[level], &key,
2219 path->slots[level]);
2220 replaced = 1;
2221 }
2222
2223 ret = walk_up_reloc_tree(reloc_root, path, &level);
2224 if (ret > 0)
2225 break;
2226
2227 BUG_ON(level == 0);
2228 /*
2229 * save the merging progress in the drop_progress.
2230 * this is OK since root refs == 1 in this case.
2231 */
2232 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2233 path->slots[level]);
2234 root_item->drop_level = level;
2235
2236 btrfs_end_transaction_throttle(trans);
2237 trans = NULL;
2238
2239 btrfs_btree_balance_dirty(fs_info);
2240
2241 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2242 invalidate_extent_cache(root, &key, &next_key);
2243 }
2244
2245 /*
2246 * handle the case only one block in the fs tree need to be
2247 * relocated and the block is tree root.
2248 */
2249 leaf = btrfs_lock_root_node(root);
2250 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2251 btrfs_tree_unlock(leaf);
2252 free_extent_buffer(leaf);
2253 if (ret < 0)
2254 err = ret;
2255 out:
2256 btrfs_free_path(path);
2257
2258 if (err == 0) {
2259 memset(&root_item->drop_progress, 0,
2260 sizeof(root_item->drop_progress));
2261 root_item->drop_level = 0;
2262 btrfs_set_root_refs(root_item, 0);
2263 btrfs_update_reloc_root(trans, root);
2264 }
2265
2266 if (trans)
2267 btrfs_end_transaction_throttle(trans);
2268
2269 btrfs_btree_balance_dirty(fs_info);
2270
2271 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2272 invalidate_extent_cache(root, &key, &next_key);
2273
2274 return err;
2275 }
2276
2277 static noinline_for_stack
2278 int prepare_to_merge(struct reloc_control *rc, int err)
2279 {
2280 struct btrfs_root *root = rc->extent_root;
2281 struct btrfs_fs_info *fs_info = root->fs_info;
2282 struct btrfs_root *reloc_root;
2283 struct btrfs_trans_handle *trans;
2284 LIST_HEAD(reloc_roots);
2285 u64 num_bytes = 0;
2286 int ret;
2287
2288 mutex_lock(&fs_info->reloc_mutex);
2289 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2290 rc->merging_rsv_size += rc->nodes_relocated * 2;
2291 mutex_unlock(&fs_info->reloc_mutex);
2292
2293 again:
2294 if (!err) {
2295 num_bytes = rc->merging_rsv_size;
2296 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2297 BTRFS_RESERVE_FLUSH_ALL);
2298 if (ret)
2299 err = ret;
2300 }
2301
2302 trans = btrfs_join_transaction(rc->extent_root);
2303 if (IS_ERR(trans)) {
2304 if (!err)
2305 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2306 num_bytes);
2307 return PTR_ERR(trans);
2308 }
2309
2310 if (!err) {
2311 if (num_bytes != rc->merging_rsv_size) {
2312 btrfs_end_transaction(trans);
2313 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2314 num_bytes);
2315 goto again;
2316 }
2317 }
2318
2319 rc->merge_reloc_tree = 1;
2320
2321 while (!list_empty(&rc->reloc_roots)) {
2322 reloc_root = list_entry(rc->reloc_roots.next,
2323 struct btrfs_root, root_list);
2324 list_del_init(&reloc_root->root_list);
2325
2326 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2327 BUG_ON(IS_ERR(root));
2328 BUG_ON(root->reloc_root != reloc_root);
2329
2330 /*
2331 * set reference count to 1, so btrfs_recover_relocation
2332 * knows it should resumes merging
2333 */
2334 if (!err)
2335 btrfs_set_root_refs(&reloc_root->root_item, 1);
2336 btrfs_update_reloc_root(trans, root);
2337
2338 list_add(&reloc_root->root_list, &reloc_roots);
2339 }
2340
2341 list_splice(&reloc_roots, &rc->reloc_roots);
2342
2343 if (!err)
2344 btrfs_commit_transaction(trans);
2345 else
2346 btrfs_end_transaction(trans);
2347 return err;
2348 }
2349
2350 static noinline_for_stack
2351 void free_reloc_roots(struct list_head *list)
2352 {
2353 struct btrfs_root *reloc_root;
2354
2355 while (!list_empty(list)) {
2356 reloc_root = list_entry(list->next, struct btrfs_root,
2357 root_list);
2358 __del_reloc_root(reloc_root);
2359 free_extent_buffer(reloc_root->node);
2360 free_extent_buffer(reloc_root->commit_root);
2361 reloc_root->node = NULL;
2362 reloc_root->commit_root = NULL;
2363 }
2364 }
2365
2366 static noinline_for_stack
2367 void merge_reloc_roots(struct reloc_control *rc)
2368 {
2369 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2370 struct btrfs_root *root;
2371 struct btrfs_root *reloc_root;
2372 LIST_HEAD(reloc_roots);
2373 int found = 0;
2374 int ret = 0;
2375 again:
2376 root = rc->extent_root;
2377
2378 /*
2379 * this serializes us with btrfs_record_root_in_transaction,
2380 * we have to make sure nobody is in the middle of
2381 * adding their roots to the list while we are
2382 * doing this splice
2383 */
2384 mutex_lock(&fs_info->reloc_mutex);
2385 list_splice_init(&rc->reloc_roots, &reloc_roots);
2386 mutex_unlock(&fs_info->reloc_mutex);
2387
2388 while (!list_empty(&reloc_roots)) {
2389 found = 1;
2390 reloc_root = list_entry(reloc_roots.next,
2391 struct btrfs_root, root_list);
2392
2393 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2394 root = read_fs_root(fs_info,
2395 reloc_root->root_key.offset);
2396 BUG_ON(IS_ERR(root));
2397 BUG_ON(root->reloc_root != reloc_root);
2398
2399 ret = merge_reloc_root(rc, root);
2400 if (ret) {
2401 if (list_empty(&reloc_root->root_list))
2402 list_add_tail(&reloc_root->root_list,
2403 &reloc_roots);
2404 goto out;
2405 }
2406 } else {
2407 list_del_init(&reloc_root->root_list);
2408 }
2409
2410 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2411 if (ret < 0) {
2412 if (list_empty(&reloc_root->root_list))
2413 list_add_tail(&reloc_root->root_list,
2414 &reloc_roots);
2415 goto out;
2416 }
2417 }
2418
2419 if (found) {
2420 found = 0;
2421 goto again;
2422 }
2423 out:
2424 if (ret) {
2425 btrfs_handle_fs_error(fs_info, ret, NULL);
2426 if (!list_empty(&reloc_roots))
2427 free_reloc_roots(&reloc_roots);
2428
2429 /* new reloc root may be added */
2430 mutex_lock(&fs_info->reloc_mutex);
2431 list_splice_init(&rc->reloc_roots, &reloc_roots);
2432 mutex_unlock(&fs_info->reloc_mutex);
2433 if (!list_empty(&reloc_roots))
2434 free_reloc_roots(&reloc_roots);
2435 }
2436
2437 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2438 }
2439
2440 static void free_block_list(struct rb_root *blocks)
2441 {
2442 struct tree_block *block;
2443 struct rb_node *rb_node;
2444 while ((rb_node = rb_first(blocks))) {
2445 block = rb_entry(rb_node, struct tree_block, rb_node);
2446 rb_erase(rb_node, blocks);
2447 kfree(block);
2448 }
2449 }
2450
2451 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2452 struct btrfs_root *reloc_root)
2453 {
2454 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2455 struct btrfs_root *root;
2456
2457 if (reloc_root->last_trans == trans->transid)
2458 return 0;
2459
2460 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2461 BUG_ON(IS_ERR(root));
2462 BUG_ON(root->reloc_root != reloc_root);
2463
2464 return btrfs_record_root_in_trans(trans, root);
2465 }
2466
2467 static noinline_for_stack
2468 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2469 struct reloc_control *rc,
2470 struct backref_node *node,
2471 struct backref_edge *edges[])
2472 {
2473 struct backref_node *next;
2474 struct btrfs_root *root;
2475 int index = 0;
2476
2477 next = node;
2478 while (1) {
2479 cond_resched();
2480 next = walk_up_backref(next, edges, &index);
2481 root = next->root;
2482 BUG_ON(!root);
2483 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2484
2485 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2486 record_reloc_root_in_trans(trans, root);
2487 break;
2488 }
2489
2490 btrfs_record_root_in_trans(trans, root);
2491 root = root->reloc_root;
2492
2493 if (next->new_bytenr != root->node->start) {
2494 BUG_ON(next->new_bytenr);
2495 BUG_ON(!list_empty(&next->list));
2496 next->new_bytenr = root->node->start;
2497 next->root = root;
2498 list_add_tail(&next->list,
2499 &rc->backref_cache.changed);
2500 __mark_block_processed(rc, next);
2501 break;
2502 }
2503
2504 WARN_ON(1);
2505 root = NULL;
2506 next = walk_down_backref(edges, &index);
2507 if (!next || next->level <= node->level)
2508 break;
2509 }
2510 if (!root)
2511 return NULL;
2512
2513 next = node;
2514 /* setup backref node path for btrfs_reloc_cow_block */
2515 while (1) {
2516 rc->backref_cache.path[next->level] = next;
2517 if (--index < 0)
2518 break;
2519 next = edges[index]->node[UPPER];
2520 }
2521 return root;
2522 }
2523
2524 /*
2525 * select a tree root for relocation. return NULL if the block
2526 * is reference counted. we should use do_relocation() in this
2527 * case. return a tree root pointer if the block isn't reference
2528 * counted. return -ENOENT if the block is root of reloc tree.
2529 */
2530 static noinline_for_stack
2531 struct btrfs_root *select_one_root(struct backref_node *node)
2532 {
2533 struct backref_node *next;
2534 struct btrfs_root *root;
2535 struct btrfs_root *fs_root = NULL;
2536 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2537 int index = 0;
2538
2539 next = node;
2540 while (1) {
2541 cond_resched();
2542 next = walk_up_backref(next, edges, &index);
2543 root = next->root;
2544 BUG_ON(!root);
2545
2546 /* no other choice for non-references counted tree */
2547 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2548 return root;
2549
2550 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2551 fs_root = root;
2552
2553 if (next != node)
2554 return NULL;
2555
2556 next = walk_down_backref(edges, &index);
2557 if (!next || next->level <= node->level)
2558 break;
2559 }
2560
2561 if (!fs_root)
2562 return ERR_PTR(-ENOENT);
2563 return fs_root;
2564 }
2565
2566 static noinline_for_stack
2567 u64 calcu_metadata_size(struct reloc_control *rc,
2568 struct backref_node *node, int reserve)
2569 {
2570 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2571 struct backref_node *next = node;
2572 struct backref_edge *edge;
2573 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2574 u64 num_bytes = 0;
2575 int index = 0;
2576
2577 BUG_ON(reserve && node->processed);
2578
2579 while (next) {
2580 cond_resched();
2581 while (1) {
2582 if (next->processed && (reserve || next != node))
2583 break;
2584
2585 num_bytes += fs_info->nodesize;
2586
2587 if (list_empty(&next->upper))
2588 break;
2589
2590 edge = list_entry(next->upper.next,
2591 struct backref_edge, list[LOWER]);
2592 edges[index++] = edge;
2593 next = edge->node[UPPER];
2594 }
2595 next = walk_down_backref(edges, &index);
2596 }
2597 return num_bytes;
2598 }
2599
2600 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2601 struct reloc_control *rc,
2602 struct backref_node *node)
2603 {
2604 struct btrfs_root *root = rc->extent_root;
2605 struct btrfs_fs_info *fs_info = root->fs_info;
2606 u64 num_bytes;
2607 int ret;
2608 u64 tmp;
2609
2610 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2611
2612 trans->block_rsv = rc->block_rsv;
2613 rc->reserved_bytes += num_bytes;
2614
2615 /*
2616 * We are under a transaction here so we can only do limited flushing.
2617 * If we get an enospc just kick back -EAGAIN so we know to drop the
2618 * transaction and try to refill when we can flush all the things.
2619 */
2620 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2621 BTRFS_RESERVE_FLUSH_LIMIT);
2622 if (ret) {
2623 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2624 while (tmp <= rc->reserved_bytes)
2625 tmp <<= 1;
2626 /*
2627 * only one thread can access block_rsv at this point,
2628 * so we don't need hold lock to protect block_rsv.
2629 * we expand more reservation size here to allow enough
2630 * space for relocation and we will return eailer in
2631 * enospc case.
2632 */
2633 rc->block_rsv->size = tmp + fs_info->nodesize *
2634 RELOCATION_RESERVED_NODES;
2635 return -EAGAIN;
2636 }
2637
2638 return 0;
2639 }
2640
2641 /*
2642 * relocate a block tree, and then update pointers in upper level
2643 * blocks that reference the block to point to the new location.
2644 *
2645 * if called by link_to_upper, the block has already been relocated.
2646 * in that case this function just updates pointers.
2647 */
2648 static int do_relocation(struct btrfs_trans_handle *trans,
2649 struct reloc_control *rc,
2650 struct backref_node *node,
2651 struct btrfs_key *key,
2652 struct btrfs_path *path, int lowest)
2653 {
2654 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2655 struct backref_node *upper;
2656 struct backref_edge *edge;
2657 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2658 struct btrfs_root *root;
2659 struct extent_buffer *eb;
2660 u32 blocksize;
2661 u64 bytenr;
2662 u64 generation;
2663 int slot;
2664 int ret;
2665 int err = 0;
2666
2667 BUG_ON(lowest && node->eb);
2668
2669 path->lowest_level = node->level + 1;
2670 rc->backref_cache.path[node->level] = node;
2671 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2672 struct btrfs_key first_key;
2673
2674 cond_resched();
2675
2676 upper = edge->node[UPPER];
2677 root = select_reloc_root(trans, rc, upper, edges);
2678 BUG_ON(!root);
2679
2680 if (upper->eb && !upper->locked) {
2681 if (!lowest) {
2682 ret = btrfs_bin_search(upper->eb, key,
2683 upper->level, &slot);
2684 BUG_ON(ret);
2685 bytenr = btrfs_node_blockptr(upper->eb, slot);
2686 if (node->eb->start == bytenr)
2687 goto next;
2688 }
2689 drop_node_buffer(upper);
2690 }
2691
2692 if (!upper->eb) {
2693 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2694 if (ret) {
2695 if (ret < 0)
2696 err = ret;
2697 else
2698 err = -ENOENT;
2699
2700 btrfs_release_path(path);
2701 break;
2702 }
2703
2704 if (!upper->eb) {
2705 upper->eb = path->nodes[upper->level];
2706 path->nodes[upper->level] = NULL;
2707 } else {
2708 BUG_ON(upper->eb != path->nodes[upper->level]);
2709 }
2710
2711 upper->locked = 1;
2712 path->locks[upper->level] = 0;
2713
2714 slot = path->slots[upper->level];
2715 btrfs_release_path(path);
2716 } else {
2717 ret = btrfs_bin_search(upper->eb, key, upper->level,
2718 &slot);
2719 BUG_ON(ret);
2720 }
2721
2722 bytenr = btrfs_node_blockptr(upper->eb, slot);
2723 if (lowest) {
2724 if (bytenr != node->bytenr) {
2725 btrfs_err(root->fs_info,
2726 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2727 bytenr, node->bytenr, slot,
2728 upper->eb->start);
2729 err = -EIO;
2730 goto next;
2731 }
2732 } else {
2733 if (node->eb->start == bytenr)
2734 goto next;
2735 }
2736
2737 blocksize = root->fs_info->nodesize;
2738 generation = btrfs_node_ptr_generation(upper->eb, slot);
2739 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2740 eb = read_tree_block(fs_info, bytenr, generation,
2741 upper->level - 1, &first_key);
2742 if (IS_ERR(eb)) {
2743 err = PTR_ERR(eb);
2744 goto next;
2745 } else if (!extent_buffer_uptodate(eb)) {
2746 free_extent_buffer(eb);
2747 err = -EIO;
2748 goto next;
2749 }
2750 btrfs_tree_lock(eb);
2751 btrfs_set_lock_blocking(eb);
2752
2753 if (!node->eb) {
2754 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2755 slot, &eb);
2756 btrfs_tree_unlock(eb);
2757 free_extent_buffer(eb);
2758 if (ret < 0) {
2759 err = ret;
2760 goto next;
2761 }
2762 BUG_ON(node->eb != eb);
2763 } else {
2764 btrfs_set_node_blockptr(upper->eb, slot,
2765 node->eb->start);
2766 btrfs_set_node_ptr_generation(upper->eb, slot,
2767 trans->transid);
2768 btrfs_mark_buffer_dirty(upper->eb);
2769
2770 ret = btrfs_inc_extent_ref(trans, root,
2771 node->eb->start, blocksize,
2772 upper->eb->start,
2773 btrfs_header_owner(upper->eb),
2774 node->level, 0);
2775 BUG_ON(ret);
2776
2777 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2778 BUG_ON(ret);
2779 }
2780 next:
2781 if (!upper->pending)
2782 drop_node_buffer(upper);
2783 else
2784 unlock_node_buffer(upper);
2785 if (err)
2786 break;
2787 }
2788
2789 if (!err && node->pending) {
2790 drop_node_buffer(node);
2791 list_move_tail(&node->list, &rc->backref_cache.changed);
2792 node->pending = 0;
2793 }
2794
2795 path->lowest_level = 0;
2796 BUG_ON(err == -ENOSPC);
2797 return err;
2798 }
2799
2800 static int link_to_upper(struct btrfs_trans_handle *trans,
2801 struct reloc_control *rc,
2802 struct backref_node *node,
2803 struct btrfs_path *path)
2804 {
2805 struct btrfs_key key;
2806
2807 btrfs_node_key_to_cpu(node->eb, &key, 0);
2808 return do_relocation(trans, rc, node, &key, path, 0);
2809 }
2810
2811 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2812 struct reloc_control *rc,
2813 struct btrfs_path *path, int err)
2814 {
2815 LIST_HEAD(list);
2816 struct backref_cache *cache = &rc->backref_cache;
2817 struct backref_node *node;
2818 int level;
2819 int ret;
2820
2821 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2822 while (!list_empty(&cache->pending[level])) {
2823 node = list_entry(cache->pending[level].next,
2824 struct backref_node, list);
2825 list_move_tail(&node->list, &list);
2826 BUG_ON(!node->pending);
2827
2828 if (!err) {
2829 ret = link_to_upper(trans, rc, node, path);
2830 if (ret < 0)
2831 err = ret;
2832 }
2833 }
2834 list_splice_init(&list, &cache->pending[level]);
2835 }
2836 return err;
2837 }
2838
2839 static void mark_block_processed(struct reloc_control *rc,
2840 u64 bytenr, u32 blocksize)
2841 {
2842 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2843 EXTENT_DIRTY);
2844 }
2845
2846 static void __mark_block_processed(struct reloc_control *rc,
2847 struct backref_node *node)
2848 {
2849 u32 blocksize;
2850 if (node->level == 0 ||
2851 in_block_group(node->bytenr, rc->block_group)) {
2852 blocksize = rc->extent_root->fs_info->nodesize;
2853 mark_block_processed(rc, node->bytenr, blocksize);
2854 }
2855 node->processed = 1;
2856 }
2857
2858 /*
2859 * mark a block and all blocks directly/indirectly reference the block
2860 * as processed.
2861 */
2862 static void update_processed_blocks(struct reloc_control *rc,
2863 struct backref_node *node)
2864 {
2865 struct backref_node *next = node;
2866 struct backref_edge *edge;
2867 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2868 int index = 0;
2869
2870 while (next) {
2871 cond_resched();
2872 while (1) {
2873 if (next->processed)
2874 break;
2875
2876 __mark_block_processed(rc, next);
2877
2878 if (list_empty(&next->upper))
2879 break;
2880
2881 edge = list_entry(next->upper.next,
2882 struct backref_edge, list[LOWER]);
2883 edges[index++] = edge;
2884 next = edge->node[UPPER];
2885 }
2886 next = walk_down_backref(edges, &index);
2887 }
2888 }
2889
2890 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2891 {
2892 u32 blocksize = rc->extent_root->fs_info->nodesize;
2893
2894 if (test_range_bit(&rc->processed_blocks, bytenr,
2895 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2896 return 1;
2897 return 0;
2898 }
2899
2900 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2901 struct tree_block *block)
2902 {
2903 struct extent_buffer *eb;
2904
2905 BUG_ON(block->key_ready);
2906 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2907 block->level, NULL);
2908 if (IS_ERR(eb)) {
2909 return PTR_ERR(eb);
2910 } else if (!extent_buffer_uptodate(eb)) {
2911 free_extent_buffer(eb);
2912 return -EIO;
2913 }
2914 WARN_ON(btrfs_header_level(eb) != block->level);
2915 if (block->level == 0)
2916 btrfs_item_key_to_cpu(eb, &block->key, 0);
2917 else
2918 btrfs_node_key_to_cpu(eb, &block->key, 0);
2919 free_extent_buffer(eb);
2920 block->key_ready = 1;
2921 return 0;
2922 }
2923
2924 /*
2925 * helper function to relocate a tree block
2926 */
2927 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2928 struct reloc_control *rc,
2929 struct backref_node *node,
2930 struct btrfs_key *key,
2931 struct btrfs_path *path)
2932 {
2933 struct btrfs_root *root;
2934 int ret = 0;
2935
2936 if (!node)
2937 return 0;
2938
2939 BUG_ON(node->processed);
2940 root = select_one_root(node);
2941 if (root == ERR_PTR(-ENOENT)) {
2942 update_processed_blocks(rc, node);
2943 goto out;
2944 }
2945
2946 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2947 ret = reserve_metadata_space(trans, rc, node);
2948 if (ret)
2949 goto out;
2950 }
2951
2952 if (root) {
2953 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2954 BUG_ON(node->new_bytenr);
2955 BUG_ON(!list_empty(&node->list));
2956 btrfs_record_root_in_trans(trans, root);
2957 root = root->reloc_root;
2958 node->new_bytenr = root->node->start;
2959 node->root = root;
2960 list_add_tail(&node->list, &rc->backref_cache.changed);
2961 } else {
2962 path->lowest_level = node->level;
2963 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2964 btrfs_release_path(path);
2965 if (ret > 0)
2966 ret = 0;
2967 }
2968 if (!ret)
2969 update_processed_blocks(rc, node);
2970 } else {
2971 ret = do_relocation(trans, rc, node, key, path, 1);
2972 }
2973 out:
2974 if (ret || node->level == 0 || node->cowonly)
2975 remove_backref_node(&rc->backref_cache, node);
2976 return ret;
2977 }
2978
2979 /*
2980 * relocate a list of blocks
2981 */
2982 static noinline_for_stack
2983 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2984 struct reloc_control *rc, struct rb_root *blocks)
2985 {
2986 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2987 struct backref_node *node;
2988 struct btrfs_path *path;
2989 struct tree_block *block;
2990 struct rb_node *rb_node;
2991 int ret;
2992 int err = 0;
2993
2994 path = btrfs_alloc_path();
2995 if (!path) {
2996 err = -ENOMEM;
2997 goto out_free_blocks;
2998 }
2999
3000 rb_node = rb_first(blocks);
3001 while (rb_node) {
3002 block = rb_entry(rb_node, struct tree_block, rb_node);
3003 if (!block->key_ready)
3004 readahead_tree_block(fs_info, block->bytenr);
3005 rb_node = rb_next(rb_node);
3006 }
3007
3008 rb_node = rb_first(blocks);
3009 while (rb_node) {
3010 block = rb_entry(rb_node, struct tree_block, rb_node);
3011 if (!block->key_ready) {
3012 err = get_tree_block_key(fs_info, block);
3013 if (err)
3014 goto out_free_path;
3015 }
3016 rb_node = rb_next(rb_node);
3017 }
3018
3019 rb_node = rb_first(blocks);
3020 while (rb_node) {
3021 block = rb_entry(rb_node, struct tree_block, rb_node);
3022
3023 node = build_backref_tree(rc, &block->key,
3024 block->level, block->bytenr);
3025 if (IS_ERR(node)) {
3026 err = PTR_ERR(node);
3027 goto out;
3028 }
3029
3030 ret = relocate_tree_block(trans, rc, node, &block->key,
3031 path);
3032 if (ret < 0) {
3033 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3034 err = ret;
3035 goto out;
3036 }
3037 rb_node = rb_next(rb_node);
3038 }
3039 out:
3040 err = finish_pending_nodes(trans, rc, path, err);
3041
3042 out_free_path:
3043 btrfs_free_path(path);
3044 out_free_blocks:
3045 free_block_list(blocks);
3046 return err;
3047 }
3048
3049 static noinline_for_stack
3050 int prealloc_file_extent_cluster(struct inode *inode,
3051 struct file_extent_cluster *cluster)
3052 {
3053 u64 alloc_hint = 0;
3054 u64 start;
3055 u64 end;
3056 u64 offset = BTRFS_I(inode)->index_cnt;
3057 u64 num_bytes;
3058 int nr = 0;
3059 int ret = 0;
3060 u64 prealloc_start = cluster->start - offset;
3061 u64 prealloc_end = cluster->end - offset;
3062 u64 cur_offset;
3063 struct extent_changeset *data_reserved = NULL;
3064
3065 BUG_ON(cluster->start != cluster->boundary[0]);
3066 inode_lock(inode);
3067
3068 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3069 prealloc_end + 1 - prealloc_start);
3070 if (ret)
3071 goto out;
3072
3073 cur_offset = prealloc_start;
3074 while (nr < cluster->nr) {
3075 start = cluster->boundary[nr] - offset;
3076 if (nr + 1 < cluster->nr)
3077 end = cluster->boundary[nr + 1] - 1 - offset;
3078 else
3079 end = cluster->end - offset;
3080
3081 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3082 num_bytes = end + 1 - start;
3083 if (cur_offset < start)
3084 btrfs_free_reserved_data_space(inode, data_reserved,
3085 cur_offset, start - cur_offset);
3086 ret = btrfs_prealloc_file_range(inode, 0, start,
3087 num_bytes, num_bytes,
3088 end + 1, &alloc_hint);
3089 cur_offset = end + 1;
3090 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3091 if (ret)
3092 break;
3093 nr++;
3094 }
3095 if (cur_offset < prealloc_end)
3096 btrfs_free_reserved_data_space(inode, data_reserved,
3097 cur_offset, prealloc_end + 1 - cur_offset);
3098 out:
3099 inode_unlock(inode);
3100 extent_changeset_free(data_reserved);
3101 return ret;
3102 }
3103
3104 static noinline_for_stack
3105 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3106 u64 block_start)
3107 {
3108 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3109 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3110 struct extent_map *em;
3111 int ret = 0;
3112
3113 em = alloc_extent_map();
3114 if (!em)
3115 return -ENOMEM;
3116
3117 em->start = start;
3118 em->len = end + 1 - start;
3119 em->block_len = em->len;
3120 em->block_start = block_start;
3121 em->bdev = fs_info->fs_devices->latest_bdev;
3122 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3123
3124 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3125 while (1) {
3126 write_lock(&em_tree->lock);
3127 ret = add_extent_mapping(em_tree, em, 0);
3128 write_unlock(&em_tree->lock);
3129 if (ret != -EEXIST) {
3130 free_extent_map(em);
3131 break;
3132 }
3133 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3134 }
3135 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3136 return ret;
3137 }
3138
3139 static int relocate_file_extent_cluster(struct inode *inode,
3140 struct file_extent_cluster *cluster)
3141 {
3142 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3143 u64 page_start;
3144 u64 page_end;
3145 u64 offset = BTRFS_I(inode)->index_cnt;
3146 unsigned long index;
3147 unsigned long last_index;
3148 struct page *page;
3149 struct file_ra_state *ra;
3150 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3151 int nr = 0;
3152 int ret = 0;
3153
3154 if (!cluster->nr)
3155 return 0;
3156
3157 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3158 if (!ra)
3159 return -ENOMEM;
3160
3161 ret = prealloc_file_extent_cluster(inode, cluster);
3162 if (ret)
3163 goto out;
3164
3165 file_ra_state_init(ra, inode->i_mapping);
3166
3167 ret = setup_extent_mapping(inode, cluster->start - offset,
3168 cluster->end - offset, cluster->start);
3169 if (ret)
3170 goto out;
3171
3172 index = (cluster->start - offset) >> PAGE_SHIFT;
3173 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3174 while (index <= last_index) {
3175 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3176 PAGE_SIZE);
3177 if (ret)
3178 goto out;
3179
3180 page = find_lock_page(inode->i_mapping, index);
3181 if (!page) {
3182 page_cache_sync_readahead(inode->i_mapping,
3183 ra, NULL, index,
3184 last_index + 1 - index);
3185 page = find_or_create_page(inode->i_mapping, index,
3186 mask);
3187 if (!page) {
3188 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3189 PAGE_SIZE, true);
3190 ret = -ENOMEM;
3191 goto out;
3192 }
3193 }
3194
3195 if (PageReadahead(page)) {
3196 page_cache_async_readahead(inode->i_mapping,
3197 ra, NULL, page, index,
3198 last_index + 1 - index);
3199 }
3200
3201 if (!PageUptodate(page)) {
3202 btrfs_readpage(NULL, page);
3203 lock_page(page);
3204 if (!PageUptodate(page)) {
3205 unlock_page(page);
3206 put_page(page);
3207 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3208 PAGE_SIZE, true);
3209 btrfs_delalloc_release_extents(BTRFS_I(inode),
3210 PAGE_SIZE, true);
3211 ret = -EIO;
3212 goto out;
3213 }
3214 }
3215
3216 page_start = page_offset(page);
3217 page_end = page_start + PAGE_SIZE - 1;
3218
3219 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3220
3221 set_page_extent_mapped(page);
3222
3223 if (nr < cluster->nr &&
3224 page_start + offset == cluster->boundary[nr]) {
3225 set_extent_bits(&BTRFS_I(inode)->io_tree,
3226 page_start, page_end,
3227 EXTENT_BOUNDARY);
3228 nr++;
3229 }
3230
3231 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3232 NULL, 0);
3233 if (ret) {
3234 unlock_page(page);
3235 put_page(page);
3236 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3237 PAGE_SIZE, true);
3238 btrfs_delalloc_release_extents(BTRFS_I(inode),
3239 PAGE_SIZE, true);
3240
3241 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3242 page_start, page_end,
3243 EXTENT_LOCKED | EXTENT_BOUNDARY);
3244 goto out;
3245
3246 }
3247 set_page_dirty(page);
3248
3249 unlock_extent(&BTRFS_I(inode)->io_tree,
3250 page_start, page_end);
3251 unlock_page(page);
3252 put_page(page);
3253
3254 index++;
3255 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3256 false);
3257 balance_dirty_pages_ratelimited(inode->i_mapping);
3258 btrfs_throttle(fs_info);
3259 }
3260 WARN_ON(nr != cluster->nr);
3261 out:
3262 kfree(ra);
3263 return ret;
3264 }
3265
3266 static noinline_for_stack
3267 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3268 struct file_extent_cluster *cluster)
3269 {
3270 int ret;
3271
3272 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3273 ret = relocate_file_extent_cluster(inode, cluster);
3274 if (ret)
3275 return ret;
3276 cluster->nr = 0;
3277 }
3278
3279 if (!cluster->nr)
3280 cluster->start = extent_key->objectid;
3281 else
3282 BUG_ON(cluster->nr >= MAX_EXTENTS);
3283 cluster->end = extent_key->objectid + extent_key->offset - 1;
3284 cluster->boundary[cluster->nr] = extent_key->objectid;
3285 cluster->nr++;
3286
3287 if (cluster->nr >= MAX_EXTENTS) {
3288 ret = relocate_file_extent_cluster(inode, cluster);
3289 if (ret)
3290 return ret;
3291 cluster->nr = 0;
3292 }
3293 return 0;
3294 }
3295
3296 /*
3297 * helper to add a tree block to the list.
3298 * the major work is getting the generation and level of the block
3299 */
3300 static int add_tree_block(struct reloc_control *rc,
3301 struct btrfs_key *extent_key,
3302 struct btrfs_path *path,
3303 struct rb_root *blocks)
3304 {
3305 struct extent_buffer *eb;
3306 struct btrfs_extent_item *ei;
3307 struct btrfs_tree_block_info *bi;
3308 struct tree_block *block;
3309 struct rb_node *rb_node;
3310 u32 item_size;
3311 int level = -1;
3312 u64 generation;
3313
3314 eb = path->nodes[0];
3315 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3316
3317 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3318 item_size >= sizeof(*ei) + sizeof(*bi)) {
3319 ei = btrfs_item_ptr(eb, path->slots[0],
3320 struct btrfs_extent_item);
3321 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3322 bi = (struct btrfs_tree_block_info *)(ei + 1);
3323 level = btrfs_tree_block_level(eb, bi);
3324 } else {
3325 level = (int)extent_key->offset;
3326 }
3327 generation = btrfs_extent_generation(eb, ei);
3328 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3329 btrfs_print_v0_err(eb->fs_info);
3330 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3331 return -EINVAL;
3332 } else {
3333 BUG();
3334 }
3335
3336 btrfs_release_path(path);
3337
3338 BUG_ON(level == -1);
3339
3340 block = kmalloc(sizeof(*block), GFP_NOFS);
3341 if (!block)
3342 return -ENOMEM;
3343
3344 block->bytenr = extent_key->objectid;
3345 block->key.objectid = rc->extent_root->fs_info->nodesize;
3346 block->key.offset = generation;
3347 block->level = level;
3348 block->key_ready = 0;
3349
3350 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3351 if (rb_node)
3352 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3353
3354 return 0;
3355 }
3356
3357 /*
3358 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3359 */
3360 static int __add_tree_block(struct reloc_control *rc,
3361 u64 bytenr, u32 blocksize,
3362 struct rb_root *blocks)
3363 {
3364 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3365 struct btrfs_path *path;
3366 struct btrfs_key key;
3367 int ret;
3368 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3369
3370 if (tree_block_processed(bytenr, rc))
3371 return 0;
3372
3373 if (tree_search(blocks, bytenr))
3374 return 0;
3375
3376 path = btrfs_alloc_path();
3377 if (!path)
3378 return -ENOMEM;
3379 again:
3380 key.objectid = bytenr;
3381 if (skinny) {
3382 key.type = BTRFS_METADATA_ITEM_KEY;
3383 key.offset = (u64)-1;
3384 } else {
3385 key.type = BTRFS_EXTENT_ITEM_KEY;
3386 key.offset = blocksize;
3387 }
3388
3389 path->search_commit_root = 1;
3390 path->skip_locking = 1;
3391 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3392 if (ret < 0)
3393 goto out;
3394
3395 if (ret > 0 && skinny) {
3396 if (path->slots[0]) {
3397 path->slots[0]--;
3398 btrfs_item_key_to_cpu(path->nodes[0], &key,
3399 path->slots[0]);
3400 if (key.objectid == bytenr &&
3401 (key.type == BTRFS_METADATA_ITEM_KEY ||
3402 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3403 key.offset == blocksize)))
3404 ret = 0;
3405 }
3406
3407 if (ret) {
3408 skinny = false;
3409 btrfs_release_path(path);
3410 goto again;
3411 }
3412 }
3413 if (ret) {
3414 ASSERT(ret == 1);
3415 btrfs_print_leaf(path->nodes[0]);
3416 btrfs_err(fs_info,
3417 "tree block extent item (%llu) is not found in extent tree",
3418 bytenr);
3419 WARN_ON(1);
3420 ret = -EINVAL;
3421 goto out;
3422 }
3423
3424 ret = add_tree_block(rc, &key, path, blocks);
3425 out:
3426 btrfs_free_path(path);
3427 return ret;
3428 }
3429
3430 /*
3431 * helper to check if the block use full backrefs for pointers in it
3432 */
3433 static int block_use_full_backref(struct reloc_control *rc,
3434 struct extent_buffer *eb)
3435 {
3436 u64 flags;
3437 int ret;
3438
3439 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3440 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3441 return 1;
3442
3443 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3444 eb->start, btrfs_header_level(eb), 1,
3445 NULL, &flags);
3446 BUG_ON(ret);
3447
3448 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3449 ret = 1;
3450 else
3451 ret = 0;
3452 return ret;
3453 }
3454
3455 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3456 struct btrfs_block_group_cache *block_group,
3457 struct inode *inode,
3458 u64 ino)
3459 {
3460 struct btrfs_key key;
3461 struct btrfs_root *root = fs_info->tree_root;
3462 struct btrfs_trans_handle *trans;
3463 int ret = 0;
3464
3465 if (inode)
3466 goto truncate;
3467
3468 key.objectid = ino;
3469 key.type = BTRFS_INODE_ITEM_KEY;
3470 key.offset = 0;
3471
3472 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3473 if (IS_ERR(inode))
3474 return -ENOENT;
3475
3476 truncate:
3477 ret = btrfs_check_trunc_cache_free_space(fs_info,
3478 &fs_info->global_block_rsv);
3479 if (ret)
3480 goto out;
3481
3482 trans = btrfs_join_transaction(root);
3483 if (IS_ERR(trans)) {
3484 ret = PTR_ERR(trans);
3485 goto out;
3486 }
3487
3488 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3489
3490 btrfs_end_transaction(trans);
3491 btrfs_btree_balance_dirty(fs_info);
3492 out:
3493 iput(inode);
3494 return ret;
3495 }
3496
3497 /*
3498 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3499 * this function scans fs tree to find blocks reference the data extent
3500 */
3501 static int find_data_references(struct reloc_control *rc,
3502 struct btrfs_key *extent_key,
3503 struct extent_buffer *leaf,
3504 struct btrfs_extent_data_ref *ref,
3505 struct rb_root *blocks)
3506 {
3507 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3508 struct btrfs_path *path;
3509 struct tree_block *block;
3510 struct btrfs_root *root;
3511 struct btrfs_file_extent_item *fi;
3512 struct rb_node *rb_node;
3513 struct btrfs_key key;
3514 u64 ref_root;
3515 u64 ref_objectid;
3516 u64 ref_offset;
3517 u32 ref_count;
3518 u32 nritems;
3519 int err = 0;
3520 int added = 0;
3521 int counted;
3522 int ret;
3523
3524 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3525 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3526 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3527 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3528
3529 /*
3530 * This is an extent belonging to the free space cache, lets just delete
3531 * it and redo the search.
3532 */
3533 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3534 ret = delete_block_group_cache(fs_info, rc->block_group,
3535 NULL, ref_objectid);
3536 if (ret != -ENOENT)
3537 return ret;
3538 ret = 0;
3539 }
3540
3541 path = btrfs_alloc_path();
3542 if (!path)
3543 return -ENOMEM;
3544 path->reada = READA_FORWARD;
3545
3546 root = read_fs_root(fs_info, ref_root);
3547 if (IS_ERR(root)) {
3548 err = PTR_ERR(root);
3549 goto out;
3550 }
3551
3552 key.objectid = ref_objectid;
3553 key.type = BTRFS_EXTENT_DATA_KEY;
3554 if (ref_offset > ((u64)-1 << 32))
3555 key.offset = 0;
3556 else
3557 key.offset = ref_offset;
3558
3559 path->search_commit_root = 1;
3560 path->skip_locking = 1;
3561 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3562 if (ret < 0) {
3563 err = ret;
3564 goto out;
3565 }
3566
3567 leaf = path->nodes[0];
3568 nritems = btrfs_header_nritems(leaf);
3569 /*
3570 * the references in tree blocks that use full backrefs
3571 * are not counted in
3572 */
3573 if (block_use_full_backref(rc, leaf))
3574 counted = 0;
3575 else
3576 counted = 1;
3577 rb_node = tree_search(blocks, leaf->start);
3578 if (rb_node) {
3579 if (counted)
3580 added = 1;
3581 else
3582 path->slots[0] = nritems;
3583 }
3584
3585 while (ref_count > 0) {
3586 while (path->slots[0] >= nritems) {
3587 ret = btrfs_next_leaf(root, path);
3588 if (ret < 0) {
3589 err = ret;
3590 goto out;
3591 }
3592 if (WARN_ON(ret > 0))
3593 goto out;
3594
3595 leaf = path->nodes[0];
3596 nritems = btrfs_header_nritems(leaf);
3597 added = 0;
3598
3599 if (block_use_full_backref(rc, leaf))
3600 counted = 0;
3601 else
3602 counted = 1;
3603 rb_node = tree_search(blocks, leaf->start);
3604 if (rb_node) {
3605 if (counted)
3606 added = 1;
3607 else
3608 path->slots[0] = nritems;
3609 }
3610 }
3611
3612 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3613 if (WARN_ON(key.objectid != ref_objectid ||
3614 key.type != BTRFS_EXTENT_DATA_KEY))
3615 break;
3616
3617 fi = btrfs_item_ptr(leaf, path->slots[0],
3618 struct btrfs_file_extent_item);
3619
3620 if (btrfs_file_extent_type(leaf, fi) ==
3621 BTRFS_FILE_EXTENT_INLINE)
3622 goto next;
3623
3624 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3625 extent_key->objectid)
3626 goto next;
3627
3628 key.offset -= btrfs_file_extent_offset(leaf, fi);
3629 if (key.offset != ref_offset)
3630 goto next;
3631
3632 if (counted)
3633 ref_count--;
3634 if (added)
3635 goto next;
3636
3637 if (!tree_block_processed(leaf->start, rc)) {
3638 block = kmalloc(sizeof(*block), GFP_NOFS);
3639 if (!block) {
3640 err = -ENOMEM;
3641 break;
3642 }
3643 block->bytenr = leaf->start;
3644 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3645 block->level = 0;
3646 block->key_ready = 1;
3647 rb_node = tree_insert(blocks, block->bytenr,
3648 &block->rb_node);
3649 if (rb_node)
3650 backref_tree_panic(rb_node, -EEXIST,
3651 block->bytenr);
3652 }
3653 if (counted)
3654 added = 1;
3655 else
3656 path->slots[0] = nritems;
3657 next:
3658 path->slots[0]++;
3659
3660 }
3661 out:
3662 btrfs_free_path(path);
3663 return err;
3664 }
3665
3666 /*
3667 * helper to find all tree blocks that reference a given data extent
3668 */
3669 static noinline_for_stack
3670 int add_data_references(struct reloc_control *rc,
3671 struct btrfs_key *extent_key,
3672 struct btrfs_path *path,
3673 struct rb_root *blocks)
3674 {
3675 struct btrfs_key key;
3676 struct extent_buffer *eb;
3677 struct btrfs_extent_data_ref *dref;
3678 struct btrfs_extent_inline_ref *iref;
3679 unsigned long ptr;
3680 unsigned long end;
3681 u32 blocksize = rc->extent_root->fs_info->nodesize;
3682 int ret = 0;
3683 int err = 0;
3684
3685 eb = path->nodes[0];
3686 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3687 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3688 ptr += sizeof(struct btrfs_extent_item);
3689
3690 while (ptr < end) {
3691 iref = (struct btrfs_extent_inline_ref *)ptr;
3692 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3693 BTRFS_REF_TYPE_DATA);
3694 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3695 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3696 ret = __add_tree_block(rc, key.offset, blocksize,
3697 blocks);
3698 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3699 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3700 ret = find_data_references(rc, extent_key,
3701 eb, dref, blocks);
3702 } else {
3703 ret = -EUCLEAN;
3704 btrfs_err(rc->extent_root->fs_info,
3705 "extent %llu slot %d has an invalid inline ref type",
3706 eb->start, path->slots[0]);
3707 }
3708 if (ret) {
3709 err = ret;
3710 goto out;
3711 }
3712 ptr += btrfs_extent_inline_ref_size(key.type);
3713 }
3714 WARN_ON(ptr > end);
3715
3716 while (1) {
3717 cond_resched();
3718 eb = path->nodes[0];
3719 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3720 ret = btrfs_next_leaf(rc->extent_root, path);
3721 if (ret < 0) {
3722 err = ret;
3723 break;
3724 }
3725 if (ret > 0)
3726 break;
3727 eb = path->nodes[0];
3728 }
3729
3730 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3731 if (key.objectid != extent_key->objectid)
3732 break;
3733
3734 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3735 ret = __add_tree_block(rc, key.offset, blocksize,
3736 blocks);
3737 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3738 dref = btrfs_item_ptr(eb, path->slots[0],
3739 struct btrfs_extent_data_ref);
3740 ret = find_data_references(rc, extent_key,
3741 eb, dref, blocks);
3742 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3743 btrfs_print_v0_err(eb->fs_info);
3744 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3745 ret = -EINVAL;
3746 } else {
3747 ret = 0;
3748 }
3749 if (ret) {
3750 err = ret;
3751 break;
3752 }
3753 path->slots[0]++;
3754 }
3755 out:
3756 btrfs_release_path(path);
3757 if (err)
3758 free_block_list(blocks);
3759 return err;
3760 }
3761
3762 /*
3763 * helper to find next unprocessed extent
3764 */
3765 static noinline_for_stack
3766 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3767 struct btrfs_key *extent_key)
3768 {
3769 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3770 struct btrfs_key key;
3771 struct extent_buffer *leaf;
3772 u64 start, end, last;
3773 int ret;
3774
3775 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3776 while (1) {
3777 cond_resched();
3778 if (rc->search_start >= last) {
3779 ret = 1;
3780 break;
3781 }
3782
3783 key.objectid = rc->search_start;
3784 key.type = BTRFS_EXTENT_ITEM_KEY;
3785 key.offset = 0;
3786
3787 path->search_commit_root = 1;
3788 path->skip_locking = 1;
3789 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3790 0, 0);
3791 if (ret < 0)
3792 break;
3793 next:
3794 leaf = path->nodes[0];
3795 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3796 ret = btrfs_next_leaf(rc->extent_root, path);
3797 if (ret != 0)
3798 break;
3799 leaf = path->nodes[0];
3800 }
3801
3802 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3803 if (key.objectid >= last) {
3804 ret = 1;
3805 break;
3806 }
3807
3808 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3809 key.type != BTRFS_METADATA_ITEM_KEY) {
3810 path->slots[0]++;
3811 goto next;
3812 }
3813
3814 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3815 key.objectid + key.offset <= rc->search_start) {
3816 path->slots[0]++;
3817 goto next;
3818 }
3819
3820 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3821 key.objectid + fs_info->nodesize <=
3822 rc->search_start) {
3823 path->slots[0]++;
3824 goto next;
3825 }
3826
3827 ret = find_first_extent_bit(&rc->processed_blocks,
3828 key.objectid, &start, &end,
3829 EXTENT_DIRTY, NULL);
3830
3831 if (ret == 0 && start <= key.objectid) {
3832 btrfs_release_path(path);
3833 rc->search_start = end + 1;
3834 } else {
3835 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3836 rc->search_start = key.objectid + key.offset;
3837 else
3838 rc->search_start = key.objectid +
3839 fs_info->nodesize;
3840 memcpy(extent_key, &key, sizeof(key));
3841 return 0;
3842 }
3843 }
3844 btrfs_release_path(path);
3845 return ret;
3846 }
3847
3848 static void set_reloc_control(struct reloc_control *rc)
3849 {
3850 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3851
3852 mutex_lock(&fs_info->reloc_mutex);
3853 fs_info->reloc_ctl = rc;
3854 mutex_unlock(&fs_info->reloc_mutex);
3855 }
3856
3857 static void unset_reloc_control(struct reloc_control *rc)
3858 {
3859 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3860
3861 mutex_lock(&fs_info->reloc_mutex);
3862 fs_info->reloc_ctl = NULL;
3863 mutex_unlock(&fs_info->reloc_mutex);
3864 }
3865
3866 static int check_extent_flags(u64 flags)
3867 {
3868 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3869 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3870 return 1;
3871 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3872 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3873 return 1;
3874 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3875 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3876 return 1;
3877 return 0;
3878 }
3879
3880 static noinline_for_stack
3881 int prepare_to_relocate(struct reloc_control *rc)
3882 {
3883 struct btrfs_trans_handle *trans;
3884 int ret;
3885
3886 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3887 BTRFS_BLOCK_RSV_TEMP);
3888 if (!rc->block_rsv)
3889 return -ENOMEM;
3890
3891 memset(&rc->cluster, 0, sizeof(rc->cluster));
3892 rc->search_start = rc->block_group->key.objectid;
3893 rc->extents_found = 0;
3894 rc->nodes_relocated = 0;
3895 rc->merging_rsv_size = 0;
3896 rc->reserved_bytes = 0;
3897 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3898 RELOCATION_RESERVED_NODES;
3899 ret = btrfs_block_rsv_refill(rc->extent_root,
3900 rc->block_rsv, rc->block_rsv->size,
3901 BTRFS_RESERVE_FLUSH_ALL);
3902 if (ret)
3903 return ret;
3904
3905 rc->create_reloc_tree = 1;
3906 set_reloc_control(rc);
3907
3908 trans = btrfs_join_transaction(rc->extent_root);
3909 if (IS_ERR(trans)) {
3910 unset_reloc_control(rc);
3911 /*
3912 * extent tree is not a ref_cow tree and has no reloc_root to
3913 * cleanup. And callers are responsible to free the above
3914 * block rsv.
3915 */
3916 return PTR_ERR(trans);
3917 }
3918 btrfs_commit_transaction(trans);
3919 return 0;
3920 }
3921
3922 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3923 {
3924 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3925 struct rb_root blocks = RB_ROOT;
3926 struct btrfs_key key;
3927 struct btrfs_trans_handle *trans = NULL;
3928 struct btrfs_path *path;
3929 struct btrfs_extent_item *ei;
3930 u64 flags;
3931 u32 item_size;
3932 int ret;
3933 int err = 0;
3934 int progress = 0;
3935
3936 path = btrfs_alloc_path();
3937 if (!path)
3938 return -ENOMEM;
3939 path->reada = READA_FORWARD;
3940
3941 ret = prepare_to_relocate(rc);
3942 if (ret) {
3943 err = ret;
3944 goto out_free;
3945 }
3946
3947 while (1) {
3948 rc->reserved_bytes = 0;
3949 ret = btrfs_block_rsv_refill(rc->extent_root,
3950 rc->block_rsv, rc->block_rsv->size,
3951 BTRFS_RESERVE_FLUSH_ALL);
3952 if (ret) {
3953 err = ret;
3954 break;
3955 }
3956 progress++;
3957 trans = btrfs_start_transaction(rc->extent_root, 0);
3958 if (IS_ERR(trans)) {
3959 err = PTR_ERR(trans);
3960 trans = NULL;
3961 break;
3962 }
3963 restart:
3964 if (update_backref_cache(trans, &rc->backref_cache)) {
3965 btrfs_end_transaction(trans);
3966 continue;
3967 }
3968
3969 ret = find_next_extent(rc, path, &key);
3970 if (ret < 0)
3971 err = ret;
3972 if (ret != 0)
3973 break;
3974
3975 rc->extents_found++;
3976
3977 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3978 struct btrfs_extent_item);
3979 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
3980 if (item_size >= sizeof(*ei)) {
3981 flags = btrfs_extent_flags(path->nodes[0], ei);
3982 ret = check_extent_flags(flags);
3983 BUG_ON(ret);
3984 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3985 err = -EINVAL;
3986 btrfs_print_v0_err(trans->fs_info);
3987 btrfs_abort_transaction(trans, err);
3988 break;
3989 } else {
3990 BUG();
3991 }
3992
3993 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3994 ret = add_tree_block(rc, &key, path, &blocks);
3995 } else if (rc->stage == UPDATE_DATA_PTRS &&
3996 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3997 ret = add_data_references(rc, &key, path, &blocks);
3998 } else {
3999 btrfs_release_path(path);
4000 ret = 0;
4001 }
4002 if (ret < 0) {
4003 err = ret;
4004 break;
4005 }
4006
4007 if (!RB_EMPTY_ROOT(&blocks)) {
4008 ret = relocate_tree_blocks(trans, rc, &blocks);
4009 if (ret < 0) {
4010 /*
4011 * if we fail to relocate tree blocks, force to update
4012 * backref cache when committing transaction.
4013 */
4014 rc->backref_cache.last_trans = trans->transid - 1;
4015
4016 if (ret != -EAGAIN) {
4017 err = ret;
4018 break;
4019 }
4020 rc->extents_found--;
4021 rc->search_start = key.objectid;
4022 }
4023 }
4024
4025 btrfs_end_transaction_throttle(trans);
4026 btrfs_btree_balance_dirty(fs_info);
4027 trans = NULL;
4028
4029 if (rc->stage == MOVE_DATA_EXTENTS &&
4030 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4031 rc->found_file_extent = 1;
4032 ret = relocate_data_extent(rc->data_inode,
4033 &key, &rc->cluster);
4034 if (ret < 0) {
4035 err = ret;
4036 break;
4037 }
4038 }
4039 }
4040 if (trans && progress && err == -ENOSPC) {
4041 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4042 if (ret == 1) {
4043 err = 0;
4044 progress = 0;
4045 goto restart;
4046 }
4047 }
4048
4049 btrfs_release_path(path);
4050 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4051
4052 if (trans) {
4053 btrfs_end_transaction_throttle(trans);
4054 btrfs_btree_balance_dirty(fs_info);
4055 }
4056
4057 if (!err) {
4058 ret = relocate_file_extent_cluster(rc->data_inode,
4059 &rc->cluster);
4060 if (ret < 0)
4061 err = ret;
4062 }
4063
4064 rc->create_reloc_tree = 0;
4065 set_reloc_control(rc);
4066
4067 backref_cache_cleanup(&rc->backref_cache);
4068 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4069
4070 err = prepare_to_merge(rc, err);
4071
4072 merge_reloc_roots(rc);
4073
4074 rc->merge_reloc_tree = 0;
4075 unset_reloc_control(rc);
4076 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4077
4078 /* get rid of pinned extents */
4079 trans = btrfs_join_transaction(rc->extent_root);
4080 if (IS_ERR(trans)) {
4081 err = PTR_ERR(trans);
4082 goto out_free;
4083 }
4084 btrfs_commit_transaction(trans);
4085 out_free:
4086 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4087 btrfs_free_path(path);
4088 return err;
4089 }
4090
4091 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4092 struct btrfs_root *root, u64 objectid)
4093 {
4094 struct btrfs_path *path;
4095 struct btrfs_inode_item *item;
4096 struct extent_buffer *leaf;
4097 int ret;
4098
4099 path = btrfs_alloc_path();
4100 if (!path)
4101 return -ENOMEM;
4102
4103 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4104 if (ret)
4105 goto out;
4106
4107 leaf = path->nodes[0];
4108 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4109 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4110 btrfs_set_inode_generation(leaf, item, 1);
4111 btrfs_set_inode_size(leaf, item, 0);
4112 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4113 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4114 BTRFS_INODE_PREALLOC);
4115 btrfs_mark_buffer_dirty(leaf);
4116 out:
4117 btrfs_free_path(path);
4118 return ret;
4119 }
4120
4121 /*
4122 * helper to create inode for data relocation.
4123 * the inode is in data relocation tree and its link count is 0
4124 */
4125 static noinline_for_stack
4126 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4127 struct btrfs_block_group_cache *group)
4128 {
4129 struct inode *inode = NULL;
4130 struct btrfs_trans_handle *trans;
4131 struct btrfs_root *root;
4132 struct btrfs_key key;
4133 u64 objectid;
4134 int err = 0;
4135
4136 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4137 if (IS_ERR(root))
4138 return ERR_CAST(root);
4139
4140 trans = btrfs_start_transaction(root, 6);
4141 if (IS_ERR(trans))
4142 return ERR_CAST(trans);
4143
4144 err = btrfs_find_free_objectid(root, &objectid);
4145 if (err)
4146 goto out;
4147
4148 err = __insert_orphan_inode(trans, root, objectid);
4149 BUG_ON(err);
4150
4151 key.objectid = objectid;
4152 key.type = BTRFS_INODE_ITEM_KEY;
4153 key.offset = 0;
4154 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4155 BUG_ON(IS_ERR(inode));
4156 BTRFS_I(inode)->index_cnt = group->key.objectid;
4157
4158 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4159 out:
4160 btrfs_end_transaction(trans);
4161 btrfs_btree_balance_dirty(fs_info);
4162 if (err) {
4163 if (inode)
4164 iput(inode);
4165 inode = ERR_PTR(err);
4166 }
4167 return inode;
4168 }
4169
4170 static struct reloc_control *alloc_reloc_control(void)
4171 {
4172 struct reloc_control *rc;
4173
4174 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4175 if (!rc)
4176 return NULL;
4177
4178 INIT_LIST_HEAD(&rc->reloc_roots);
4179 backref_cache_init(&rc->backref_cache);
4180 mapping_tree_init(&rc->reloc_root_tree);
4181 extent_io_tree_init(&rc->processed_blocks, NULL);
4182 return rc;
4183 }
4184
4185 /*
4186 * Print the block group being relocated
4187 */
4188 static void describe_relocation(struct btrfs_fs_info *fs_info,
4189 struct btrfs_block_group_cache *block_group)
4190 {
4191 char buf[128]; /* prefixed by a '|' that'll be dropped */
4192 u64 flags = block_group->flags;
4193
4194 /* Shouldn't happen */
4195 if (!flags) {
4196 strcpy(buf, "|NONE");
4197 } else {
4198 char *bp = buf;
4199
4200 #define DESCRIBE_FLAG(f, d) \
4201 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4202 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4203 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4204 }
4205 DESCRIBE_FLAG(DATA, "data");
4206 DESCRIBE_FLAG(SYSTEM, "system");
4207 DESCRIBE_FLAG(METADATA, "metadata");
4208 DESCRIBE_FLAG(RAID0, "raid0");
4209 DESCRIBE_FLAG(RAID1, "raid1");
4210 DESCRIBE_FLAG(DUP, "dup");
4211 DESCRIBE_FLAG(RAID10, "raid10");
4212 DESCRIBE_FLAG(RAID5, "raid5");
4213 DESCRIBE_FLAG(RAID6, "raid6");
4214 if (flags)
4215 snprintf(bp, buf - bp + sizeof(buf), "|0x%llx", flags);
4216 #undef DESCRIBE_FLAG
4217 }
4218
4219 btrfs_info(fs_info,
4220 "relocating block group %llu flags %s",
4221 block_group->key.objectid, buf + 1);
4222 }
4223
4224 /*
4225 * function to relocate all extents in a block group.
4226 */
4227 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4228 {
4229 struct btrfs_root *extent_root = fs_info->extent_root;
4230 struct reloc_control *rc;
4231 struct inode *inode;
4232 struct btrfs_path *path;
4233 int ret;
4234 int rw = 0;
4235 int err = 0;
4236
4237 rc = alloc_reloc_control();
4238 if (!rc)
4239 return -ENOMEM;
4240
4241 rc->extent_root = extent_root;
4242
4243 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4244 BUG_ON(!rc->block_group);
4245
4246 ret = btrfs_inc_block_group_ro(rc->block_group);
4247 if (ret) {
4248 err = ret;
4249 goto out;
4250 }
4251 rw = 1;
4252
4253 path = btrfs_alloc_path();
4254 if (!path) {
4255 err = -ENOMEM;
4256 goto out;
4257 }
4258
4259 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4260 btrfs_free_path(path);
4261
4262 if (!IS_ERR(inode))
4263 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4264 else
4265 ret = PTR_ERR(inode);
4266
4267 if (ret && ret != -ENOENT) {
4268 err = ret;
4269 goto out;
4270 }
4271
4272 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4273 if (IS_ERR(rc->data_inode)) {
4274 err = PTR_ERR(rc->data_inode);
4275 rc->data_inode = NULL;
4276 goto out;
4277 }
4278
4279 describe_relocation(fs_info, rc->block_group);
4280
4281 btrfs_wait_block_group_reservations(rc->block_group);
4282 btrfs_wait_nocow_writers(rc->block_group);
4283 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4284 rc->block_group->key.objectid,
4285 rc->block_group->key.offset);
4286
4287 while (1) {
4288 mutex_lock(&fs_info->cleaner_mutex);
4289 ret = relocate_block_group(rc);
4290 mutex_unlock(&fs_info->cleaner_mutex);
4291 if (ret < 0) {
4292 err = ret;
4293 goto out;
4294 }
4295
4296 if (rc->extents_found == 0)
4297 break;
4298
4299 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4300
4301 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4302 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4303 (u64)-1);
4304 if (ret) {
4305 err = ret;
4306 goto out;
4307 }
4308 invalidate_mapping_pages(rc->data_inode->i_mapping,
4309 0, -1);
4310 rc->stage = UPDATE_DATA_PTRS;
4311 }
4312 }
4313
4314 WARN_ON(rc->block_group->pinned > 0);
4315 WARN_ON(rc->block_group->reserved > 0);
4316 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4317 out:
4318 if (err && rw)
4319 btrfs_dec_block_group_ro(rc->block_group);
4320 iput(rc->data_inode);
4321 btrfs_put_block_group(rc->block_group);
4322 kfree(rc);
4323 return err;
4324 }
4325
4326 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4327 {
4328 struct btrfs_fs_info *fs_info = root->fs_info;
4329 struct btrfs_trans_handle *trans;
4330 int ret, err;
4331
4332 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4333 if (IS_ERR(trans))
4334 return PTR_ERR(trans);
4335
4336 memset(&root->root_item.drop_progress, 0,
4337 sizeof(root->root_item.drop_progress));
4338 root->root_item.drop_level = 0;
4339 btrfs_set_root_refs(&root->root_item, 0);
4340 ret = btrfs_update_root(trans, fs_info->tree_root,
4341 &root->root_key, &root->root_item);
4342
4343 err = btrfs_end_transaction(trans);
4344 if (err)
4345 return err;
4346 return ret;
4347 }
4348
4349 /*
4350 * recover relocation interrupted by system crash.
4351 *
4352 * this function resumes merging reloc trees with corresponding fs trees.
4353 * this is important for keeping the sharing of tree blocks
4354 */
4355 int btrfs_recover_relocation(struct btrfs_root *root)
4356 {
4357 struct btrfs_fs_info *fs_info = root->fs_info;
4358 LIST_HEAD(reloc_roots);
4359 struct btrfs_key key;
4360 struct btrfs_root *fs_root;
4361 struct btrfs_root *reloc_root;
4362 struct btrfs_path *path;
4363 struct extent_buffer *leaf;
4364 struct reloc_control *rc = NULL;
4365 struct btrfs_trans_handle *trans;
4366 int ret;
4367 int err = 0;
4368
4369 path = btrfs_alloc_path();
4370 if (!path)
4371 return -ENOMEM;
4372 path->reada = READA_BACK;
4373
4374 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4375 key.type = BTRFS_ROOT_ITEM_KEY;
4376 key.offset = (u64)-1;
4377
4378 while (1) {
4379 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4380 path, 0, 0);
4381 if (ret < 0) {
4382 err = ret;
4383 goto out;
4384 }
4385 if (ret > 0) {
4386 if (path->slots[0] == 0)
4387 break;
4388 path->slots[0]--;
4389 }
4390 leaf = path->nodes[0];
4391 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4392 btrfs_release_path(path);
4393
4394 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4395 key.type != BTRFS_ROOT_ITEM_KEY)
4396 break;
4397
4398 reloc_root = btrfs_read_fs_root(root, &key);
4399 if (IS_ERR(reloc_root)) {
4400 err = PTR_ERR(reloc_root);
4401 goto out;
4402 }
4403
4404 list_add(&reloc_root->root_list, &reloc_roots);
4405
4406 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4407 fs_root = read_fs_root(fs_info,
4408 reloc_root->root_key.offset);
4409 if (IS_ERR(fs_root)) {
4410 ret = PTR_ERR(fs_root);
4411 if (ret != -ENOENT) {
4412 err = ret;
4413 goto out;
4414 }
4415 ret = mark_garbage_root(reloc_root);
4416 if (ret < 0) {
4417 err = ret;
4418 goto out;
4419 }
4420 }
4421 }
4422
4423 if (key.offset == 0)
4424 break;
4425
4426 key.offset--;
4427 }
4428 btrfs_release_path(path);
4429
4430 if (list_empty(&reloc_roots))
4431 goto out;
4432
4433 rc = alloc_reloc_control();
4434 if (!rc) {
4435 err = -ENOMEM;
4436 goto out;
4437 }
4438
4439 rc->extent_root = fs_info->extent_root;
4440
4441 set_reloc_control(rc);
4442
4443 trans = btrfs_join_transaction(rc->extent_root);
4444 if (IS_ERR(trans)) {
4445 unset_reloc_control(rc);
4446 err = PTR_ERR(trans);
4447 goto out_free;
4448 }
4449
4450 rc->merge_reloc_tree = 1;
4451
4452 while (!list_empty(&reloc_roots)) {
4453 reloc_root = list_entry(reloc_roots.next,
4454 struct btrfs_root, root_list);
4455 list_del(&reloc_root->root_list);
4456
4457 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4458 list_add_tail(&reloc_root->root_list,
4459 &rc->reloc_roots);
4460 continue;
4461 }
4462
4463 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4464 if (IS_ERR(fs_root)) {
4465 err = PTR_ERR(fs_root);
4466 goto out_free;
4467 }
4468
4469 err = __add_reloc_root(reloc_root);
4470 BUG_ON(err < 0); /* -ENOMEM or logic error */
4471 fs_root->reloc_root = reloc_root;
4472 }
4473
4474 err = btrfs_commit_transaction(trans);
4475 if (err)
4476 goto out_free;
4477
4478 merge_reloc_roots(rc);
4479
4480 unset_reloc_control(rc);
4481
4482 trans = btrfs_join_transaction(rc->extent_root);
4483 if (IS_ERR(trans)) {
4484 err = PTR_ERR(trans);
4485 goto out_free;
4486 }
4487 err = btrfs_commit_transaction(trans);
4488 out_free:
4489 kfree(rc);
4490 out:
4491 if (!list_empty(&reloc_roots))
4492 free_reloc_roots(&reloc_roots);
4493
4494 btrfs_free_path(path);
4495
4496 if (err == 0) {
4497 /* cleanup orphan inode in data relocation tree */
4498 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4499 if (IS_ERR(fs_root))
4500 err = PTR_ERR(fs_root);
4501 else
4502 err = btrfs_orphan_cleanup(fs_root);
4503 }
4504 return err;
4505 }
4506
4507 /*
4508 * helper to add ordered checksum for data relocation.
4509 *
4510 * cloning checksum properly handles the nodatasum extents.
4511 * it also saves CPU time to re-calculate the checksum.
4512 */
4513 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4514 {
4515 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4516 struct btrfs_ordered_sum *sums;
4517 struct btrfs_ordered_extent *ordered;
4518 int ret;
4519 u64 disk_bytenr;
4520 u64 new_bytenr;
4521 LIST_HEAD(list);
4522
4523 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4524 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4525
4526 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4527 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4528 disk_bytenr + len - 1, &list, 0);
4529 if (ret)
4530 goto out;
4531
4532 while (!list_empty(&list)) {
4533 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4534 list_del_init(&sums->list);
4535
4536 /*
4537 * We need to offset the new_bytenr based on where the csum is.
4538 * We need to do this because we will read in entire prealloc
4539 * extents but we may have written to say the middle of the
4540 * prealloc extent, so we need to make sure the csum goes with
4541 * the right disk offset.
4542 *
4543 * We can do this because the data reloc inode refers strictly
4544 * to the on disk bytes, so we don't have to worry about
4545 * disk_len vs real len like with real inodes since it's all
4546 * disk length.
4547 */
4548 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4549 sums->bytenr = new_bytenr;
4550
4551 btrfs_add_ordered_sum(inode, ordered, sums);
4552 }
4553 out:
4554 btrfs_put_ordered_extent(ordered);
4555 return ret;
4556 }
4557
4558 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4559 struct btrfs_root *root, struct extent_buffer *buf,
4560 struct extent_buffer *cow)
4561 {
4562 struct btrfs_fs_info *fs_info = root->fs_info;
4563 struct reloc_control *rc;
4564 struct backref_node *node;
4565 int first_cow = 0;
4566 int level;
4567 int ret = 0;
4568
4569 rc = fs_info->reloc_ctl;
4570 if (!rc)
4571 return 0;
4572
4573 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4574 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4575
4576 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4577 if (buf == root->node)
4578 __update_reloc_root(root, cow->start);
4579 }
4580
4581 level = btrfs_header_level(buf);
4582 if (btrfs_header_generation(buf) <=
4583 btrfs_root_last_snapshot(&root->root_item))
4584 first_cow = 1;
4585
4586 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4587 rc->create_reloc_tree) {
4588 WARN_ON(!first_cow && level == 0);
4589
4590 node = rc->backref_cache.path[level];
4591 BUG_ON(node->bytenr != buf->start &&
4592 node->new_bytenr != buf->start);
4593
4594 drop_node_buffer(node);
4595 extent_buffer_get(cow);
4596 node->eb = cow;
4597 node->new_bytenr = cow->start;
4598
4599 if (!node->pending) {
4600 list_move_tail(&node->list,
4601 &rc->backref_cache.pending[level]);
4602 node->pending = 1;
4603 }
4604
4605 if (first_cow)
4606 __mark_block_processed(rc, node);
4607
4608 if (first_cow && level > 0)
4609 rc->nodes_relocated += buf->len;
4610 }
4611
4612 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4613 ret = replace_file_extents(trans, rc, root, cow);
4614 return ret;
4615 }
4616
4617 /*
4618 * called before creating snapshot. it calculates metadata reservation
4619 * required for relocating tree blocks in the snapshot
4620 */
4621 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4622 u64 *bytes_to_reserve)
4623 {
4624 struct btrfs_root *root;
4625 struct reloc_control *rc;
4626
4627 root = pending->root;
4628 if (!root->reloc_root)
4629 return;
4630
4631 rc = root->fs_info->reloc_ctl;
4632 if (!rc->merge_reloc_tree)
4633 return;
4634
4635 root = root->reloc_root;
4636 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4637 /*
4638 * relocation is in the stage of merging trees. the space
4639 * used by merging a reloc tree is twice the size of
4640 * relocated tree nodes in the worst case. half for cowing
4641 * the reloc tree, half for cowing the fs tree. the space
4642 * used by cowing the reloc tree will be freed after the
4643 * tree is dropped. if we create snapshot, cowing the fs
4644 * tree may use more space than it frees. so we need
4645 * reserve extra space.
4646 */
4647 *bytes_to_reserve += rc->nodes_relocated;
4648 }
4649
4650 /*
4651 * called after snapshot is created. migrate block reservation
4652 * and create reloc root for the newly created snapshot
4653 */
4654 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4655 struct btrfs_pending_snapshot *pending)
4656 {
4657 struct btrfs_root *root = pending->root;
4658 struct btrfs_root *reloc_root;
4659 struct btrfs_root *new_root;
4660 struct reloc_control *rc;
4661 int ret;
4662
4663 if (!root->reloc_root)
4664 return 0;
4665
4666 rc = root->fs_info->reloc_ctl;
4667 rc->merging_rsv_size += rc->nodes_relocated;
4668
4669 if (rc->merge_reloc_tree) {
4670 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4671 rc->block_rsv,
4672 rc->nodes_relocated, 1);
4673 if (ret)
4674 return ret;
4675 }
4676
4677 new_root = pending->snap;
4678 reloc_root = create_reloc_root(trans, root->reloc_root,
4679 new_root->root_key.objectid);
4680 if (IS_ERR(reloc_root))
4681 return PTR_ERR(reloc_root);
4682
4683 ret = __add_reloc_root(reloc_root);
4684 BUG_ON(ret < 0);
4685 new_root->reloc_root = reloc_root;
4686
4687 if (rc->create_reloc_tree)
4688 ret = clone_backref_node(trans, rc, root, reloc_root);
4689 return ret;
4690 }
(deprecated) Btrfs devel tree