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[mirror_ubuntu-hirsute-kernel.git] / fs / btrfs / relocation.c
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 #include "delalloc-space.h"
24 #include "block-group.h"
25
26 /*
27 * backref_node, mapping_node and tree_block start with this
28 */
29 struct tree_entry {
30 struct rb_node rb_node;
31 u64 bytenr;
32 };
33
34 /*
35 * present a tree block in the backref cache
36 */
37 struct backref_node {
38 struct rb_node rb_node;
39 u64 bytenr;
40
41 u64 new_bytenr;
42 /* objectid of tree block owner, can be not uptodate */
43 u64 owner;
44 /* link to pending, changed or detached list */
45 struct list_head list;
46 /* list of upper level blocks reference this block */
47 struct list_head upper;
48 /* list of child blocks in the cache */
49 struct list_head lower;
50 /* NULL if this node is not tree root */
51 struct btrfs_root *root;
52 /* extent buffer got by COW the block */
53 struct extent_buffer *eb;
54 /* level of tree block */
55 unsigned int level:8;
56 /* is the block in non-reference counted tree */
57 unsigned int cowonly:1;
58 /* 1 if no child node in the cache */
59 unsigned int lowest:1;
60 /* is the extent buffer locked */
61 unsigned int locked:1;
62 /* has the block been processed */
63 unsigned int processed:1;
64 /* have backrefs of this block been checked */
65 unsigned int checked:1;
66 /*
67 * 1 if corresponding block has been cowed but some upper
68 * level block pointers may not point to the new location
69 */
70 unsigned int pending:1;
71 /*
72 * 1 if the backref node isn't connected to any other
73 * backref node.
74 */
75 unsigned int detached:1;
76 };
77
78 /*
79 * present a block pointer in the backref cache
80 */
81 struct backref_edge {
82 struct list_head list[2];
83 struct backref_node *node[2];
84 };
85
86 #define LOWER 0
87 #define UPPER 1
88 #define RELOCATION_RESERVED_NODES 256
89
90 struct backref_cache {
91 /* red black tree of all backref nodes in the cache */
92 struct rb_root rb_root;
93 /* for passing backref nodes to btrfs_reloc_cow_block */
94 struct backref_node *path[BTRFS_MAX_LEVEL];
95 /*
96 * list of blocks that have been cowed but some block
97 * pointers in upper level blocks may not reflect the
98 * new location
99 */
100 struct list_head pending[BTRFS_MAX_LEVEL];
101 /* list of backref nodes with no child node */
102 struct list_head leaves;
103 /* list of blocks that have been cowed in current transaction */
104 struct list_head changed;
105 /* list of detached backref node. */
106 struct list_head detached;
107
108 u64 last_trans;
109
110 int nr_nodes;
111 int nr_edges;
112 };
113
114 /*
115 * map address of tree root to tree
116 */
117 struct mapping_node {
118 struct rb_node rb_node;
119 u64 bytenr;
120 void *data;
121 };
122
123 struct mapping_tree {
124 struct rb_root rb_root;
125 spinlock_t lock;
126 };
127
128 /*
129 * present a tree block to process
130 */
131 struct tree_block {
132 struct rb_node rb_node;
133 u64 bytenr;
134 struct btrfs_key key;
135 unsigned int level:8;
136 unsigned int key_ready:1;
137 };
138
139 #define MAX_EXTENTS 128
140
141 struct file_extent_cluster {
142 u64 start;
143 u64 end;
144 u64 boundary[MAX_EXTENTS];
145 unsigned int nr;
146 };
147
148 struct reloc_control {
149 /* block group to relocate */
150 struct btrfs_block_group *block_group;
151 /* extent tree */
152 struct btrfs_root *extent_root;
153 /* inode for moving data */
154 struct inode *data_inode;
155
156 struct btrfs_block_rsv *block_rsv;
157
158 struct backref_cache backref_cache;
159
160 struct file_extent_cluster cluster;
161 /* tree blocks have been processed */
162 struct extent_io_tree processed_blocks;
163 /* map start of tree root to corresponding reloc tree */
164 struct mapping_tree reloc_root_tree;
165 /* list of reloc trees */
166 struct list_head reloc_roots;
167 /* list of subvolume trees that get relocated */
168 struct list_head dirty_subvol_roots;
169 /* size of metadata reservation for merging reloc trees */
170 u64 merging_rsv_size;
171 /* size of relocated tree nodes */
172 u64 nodes_relocated;
173 /* reserved size for block group relocation*/
174 u64 reserved_bytes;
175
176 u64 search_start;
177 u64 extents_found;
178
179 unsigned int stage:8;
180 unsigned int create_reloc_tree:1;
181 unsigned int merge_reloc_tree:1;
182 unsigned int found_file_extent:1;
183 };
184
185 /* stages of data relocation */
186 #define MOVE_DATA_EXTENTS 0
187 #define UPDATE_DATA_PTRS 1
188
189 static void remove_backref_node(struct backref_cache *cache,
190 struct backref_node *node);
191 static void __mark_block_processed(struct reloc_control *rc,
192 struct backref_node *node);
193
194 static void mapping_tree_init(struct mapping_tree *tree)
195 {
196 tree->rb_root = RB_ROOT;
197 spin_lock_init(&tree->lock);
198 }
199
200 static void backref_cache_init(struct backref_cache *cache)
201 {
202 int i;
203 cache->rb_root = RB_ROOT;
204 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
205 INIT_LIST_HEAD(&cache->pending[i]);
206 INIT_LIST_HEAD(&cache->changed);
207 INIT_LIST_HEAD(&cache->detached);
208 INIT_LIST_HEAD(&cache->leaves);
209 }
210
211 static void backref_cache_cleanup(struct backref_cache *cache)
212 {
213 struct backref_node *node;
214 int i;
215
216 while (!list_empty(&cache->detached)) {
217 node = list_entry(cache->detached.next,
218 struct backref_node, list);
219 remove_backref_node(cache, node);
220 }
221
222 while (!list_empty(&cache->leaves)) {
223 node = list_entry(cache->leaves.next,
224 struct backref_node, lower);
225 remove_backref_node(cache, node);
226 }
227
228 cache->last_trans = 0;
229
230 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
231 ASSERT(list_empty(&cache->pending[i]));
232 ASSERT(list_empty(&cache->changed));
233 ASSERT(list_empty(&cache->detached));
234 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
235 ASSERT(!cache->nr_nodes);
236 ASSERT(!cache->nr_edges);
237 }
238
239 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
240 {
241 struct backref_node *node;
242
243 node = kzalloc(sizeof(*node), GFP_NOFS);
244 if (node) {
245 INIT_LIST_HEAD(&node->list);
246 INIT_LIST_HEAD(&node->upper);
247 INIT_LIST_HEAD(&node->lower);
248 RB_CLEAR_NODE(&node->rb_node);
249 cache->nr_nodes++;
250 }
251 return node;
252 }
253
254 static void free_backref_node(struct backref_cache *cache,
255 struct backref_node *node)
256 {
257 if (node) {
258 cache->nr_nodes--;
259 kfree(node);
260 }
261 }
262
263 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
264 {
265 struct backref_edge *edge;
266
267 edge = kzalloc(sizeof(*edge), GFP_NOFS);
268 if (edge)
269 cache->nr_edges++;
270 return edge;
271 }
272
273 static void free_backref_edge(struct backref_cache *cache,
274 struct backref_edge *edge)
275 {
276 if (edge) {
277 cache->nr_edges--;
278 kfree(edge);
279 }
280 }
281
282 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
283 struct rb_node *node)
284 {
285 struct rb_node **p = &root->rb_node;
286 struct rb_node *parent = NULL;
287 struct tree_entry *entry;
288
289 while (*p) {
290 parent = *p;
291 entry = rb_entry(parent, struct tree_entry, rb_node);
292
293 if (bytenr < entry->bytenr)
294 p = &(*p)->rb_left;
295 else if (bytenr > entry->bytenr)
296 p = &(*p)->rb_right;
297 else
298 return parent;
299 }
300
301 rb_link_node(node, parent, p);
302 rb_insert_color(node, root);
303 return NULL;
304 }
305
306 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
307 {
308 struct rb_node *n = root->rb_node;
309 struct tree_entry *entry;
310
311 while (n) {
312 entry = rb_entry(n, struct tree_entry, rb_node);
313
314 if (bytenr < entry->bytenr)
315 n = n->rb_left;
316 else if (bytenr > entry->bytenr)
317 n = n->rb_right;
318 else
319 return n;
320 }
321 return NULL;
322 }
323
324 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
325 {
326
327 struct btrfs_fs_info *fs_info = NULL;
328 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
329 rb_node);
330 if (bnode->root)
331 fs_info = bnode->root->fs_info;
332 btrfs_panic(fs_info, errno,
333 "Inconsistency in backref cache found at offset %llu",
334 bytenr);
335 }
336
337 /*
338 * walk up backref nodes until reach node presents tree root
339 */
340 static struct backref_node *walk_up_backref(struct backref_node *node,
341 struct backref_edge *edges[],
342 int *index)
343 {
344 struct backref_edge *edge;
345 int idx = *index;
346
347 while (!list_empty(&node->upper)) {
348 edge = list_entry(node->upper.next,
349 struct backref_edge, list[LOWER]);
350 edges[idx++] = edge;
351 node = edge->node[UPPER];
352 }
353 BUG_ON(node->detached);
354 *index = idx;
355 return node;
356 }
357
358 /*
359 * walk down backref nodes to find start of next reference path
360 */
361 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
362 int *index)
363 {
364 struct backref_edge *edge;
365 struct backref_node *lower;
366 int idx = *index;
367
368 while (idx > 0) {
369 edge = edges[idx - 1];
370 lower = edge->node[LOWER];
371 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
372 idx--;
373 continue;
374 }
375 edge = list_entry(edge->list[LOWER].next,
376 struct backref_edge, list[LOWER]);
377 edges[idx - 1] = edge;
378 *index = idx;
379 return edge->node[UPPER];
380 }
381 *index = 0;
382 return NULL;
383 }
384
385 static void unlock_node_buffer(struct backref_node *node)
386 {
387 if (node->locked) {
388 btrfs_tree_unlock(node->eb);
389 node->locked = 0;
390 }
391 }
392
393 static void drop_node_buffer(struct backref_node *node)
394 {
395 if (node->eb) {
396 unlock_node_buffer(node);
397 free_extent_buffer(node->eb);
398 node->eb = NULL;
399 }
400 }
401
402 static void drop_backref_node(struct backref_cache *tree,
403 struct backref_node *node)
404 {
405 BUG_ON(!list_empty(&node->upper));
406
407 drop_node_buffer(node);
408 list_del(&node->list);
409 list_del(&node->lower);
410 if (!RB_EMPTY_NODE(&node->rb_node))
411 rb_erase(&node->rb_node, &tree->rb_root);
412 free_backref_node(tree, node);
413 }
414
415 /*
416 * remove a backref node from the backref cache
417 */
418 static void remove_backref_node(struct backref_cache *cache,
419 struct backref_node *node)
420 {
421 struct backref_node *upper;
422 struct backref_edge *edge;
423
424 if (!node)
425 return;
426
427 BUG_ON(!node->lowest && !node->detached);
428 while (!list_empty(&node->upper)) {
429 edge = list_entry(node->upper.next, struct backref_edge,
430 list[LOWER]);
431 upper = edge->node[UPPER];
432 list_del(&edge->list[LOWER]);
433 list_del(&edge->list[UPPER]);
434 free_backref_edge(cache, edge);
435
436 if (RB_EMPTY_NODE(&upper->rb_node)) {
437 BUG_ON(!list_empty(&node->upper));
438 drop_backref_node(cache, node);
439 node = upper;
440 node->lowest = 1;
441 continue;
442 }
443 /*
444 * add the node to leaf node list if no other
445 * child block cached.
446 */
447 if (list_empty(&upper->lower)) {
448 list_add_tail(&upper->lower, &cache->leaves);
449 upper->lowest = 1;
450 }
451 }
452
453 drop_backref_node(cache, node);
454 }
455
456 static void update_backref_node(struct backref_cache *cache,
457 struct backref_node *node, u64 bytenr)
458 {
459 struct rb_node *rb_node;
460 rb_erase(&node->rb_node, &cache->rb_root);
461 node->bytenr = bytenr;
462 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
463 if (rb_node)
464 backref_tree_panic(rb_node, -EEXIST, bytenr);
465 }
466
467 /*
468 * update backref cache after a transaction commit
469 */
470 static int update_backref_cache(struct btrfs_trans_handle *trans,
471 struct backref_cache *cache)
472 {
473 struct backref_node *node;
474 int level = 0;
475
476 if (cache->last_trans == 0) {
477 cache->last_trans = trans->transid;
478 return 0;
479 }
480
481 if (cache->last_trans == trans->transid)
482 return 0;
483
484 /*
485 * detached nodes are used to avoid unnecessary backref
486 * lookup. transaction commit changes the extent tree.
487 * so the detached nodes are no longer useful.
488 */
489 while (!list_empty(&cache->detached)) {
490 node = list_entry(cache->detached.next,
491 struct backref_node, list);
492 remove_backref_node(cache, node);
493 }
494
495 while (!list_empty(&cache->changed)) {
496 node = list_entry(cache->changed.next,
497 struct backref_node, list);
498 list_del_init(&node->list);
499 BUG_ON(node->pending);
500 update_backref_node(cache, node, node->new_bytenr);
501 }
502
503 /*
504 * some nodes can be left in the pending list if there were
505 * errors during processing the pending nodes.
506 */
507 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
508 list_for_each_entry(node, &cache->pending[level], list) {
509 BUG_ON(!node->pending);
510 if (node->bytenr == node->new_bytenr)
511 continue;
512 update_backref_node(cache, node, node->new_bytenr);
513 }
514 }
515
516 cache->last_trans = 0;
517 return 1;
518 }
519
520
521 static int should_ignore_root(struct btrfs_root *root)
522 {
523 struct btrfs_root *reloc_root;
524
525 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
526 return 0;
527
528 reloc_root = root->reloc_root;
529 if (!reloc_root)
530 return 0;
531
532 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
533 root->fs_info->running_transaction->transid - 1)
534 return 0;
535 /*
536 * if there is reloc tree and it was created in previous
537 * transaction backref lookup can find the reloc tree,
538 * so backref node for the fs tree root is useless for
539 * relocation.
540 */
541 return 1;
542 }
543 /*
544 * find reloc tree by address of tree root
545 */
546 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
547 u64 bytenr)
548 {
549 struct rb_node *rb_node;
550 struct mapping_node *node;
551 struct btrfs_root *root = NULL;
552
553 spin_lock(&rc->reloc_root_tree.lock);
554 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
555 if (rb_node) {
556 node = rb_entry(rb_node, struct mapping_node, rb_node);
557 root = (struct btrfs_root *)node->data;
558 }
559 spin_unlock(&rc->reloc_root_tree.lock);
560 return root;
561 }
562
563 static int is_cowonly_root(u64 root_objectid)
564 {
565 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
566 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
567 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
568 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
569 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
570 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
571 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
572 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
573 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
574 return 1;
575 return 0;
576 }
577
578 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
579 u64 root_objectid)
580 {
581 struct btrfs_key key;
582
583 key.objectid = root_objectid;
584 key.type = BTRFS_ROOT_ITEM_KEY;
585 if (is_cowonly_root(root_objectid))
586 key.offset = 0;
587 else
588 key.offset = (u64)-1;
589
590 return btrfs_get_fs_root(fs_info, &key, false);
591 }
592
593 static noinline_for_stack
594 int find_inline_backref(struct extent_buffer *leaf, int slot,
595 unsigned long *ptr, unsigned long *end)
596 {
597 struct btrfs_key key;
598 struct btrfs_extent_item *ei;
599 struct btrfs_tree_block_info *bi;
600 u32 item_size;
601
602 btrfs_item_key_to_cpu(leaf, &key, slot);
603
604 item_size = btrfs_item_size_nr(leaf, slot);
605 if (item_size < sizeof(*ei)) {
606 btrfs_print_v0_err(leaf->fs_info);
607 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
608 return 1;
609 }
610 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
611 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
612 BTRFS_EXTENT_FLAG_TREE_BLOCK));
613
614 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
615 item_size <= sizeof(*ei) + sizeof(*bi)) {
616 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
617 return 1;
618 }
619 if (key.type == BTRFS_METADATA_ITEM_KEY &&
620 item_size <= sizeof(*ei)) {
621 WARN_ON(item_size < sizeof(*ei));
622 return 1;
623 }
624
625 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
626 bi = (struct btrfs_tree_block_info *)(ei + 1);
627 *ptr = (unsigned long)(bi + 1);
628 } else {
629 *ptr = (unsigned long)(ei + 1);
630 }
631 *end = (unsigned long)ei + item_size;
632 return 0;
633 }
634
635 /*
636 * build backref tree for a given tree block. root of the backref tree
637 * corresponds the tree block, leaves of the backref tree correspond
638 * roots of b-trees that reference the tree block.
639 *
640 * the basic idea of this function is check backrefs of a given block
641 * to find upper level blocks that reference the block, and then check
642 * backrefs of these upper level blocks recursively. the recursion stop
643 * when tree root is reached or backrefs for the block is cached.
644 *
645 * NOTE: if we find backrefs for a block are cached, we know backrefs
646 * for all upper level blocks that directly/indirectly reference the
647 * block are also cached.
648 */
649 static noinline_for_stack
650 struct backref_node *build_backref_tree(struct reloc_control *rc,
651 struct btrfs_key *node_key,
652 int level, u64 bytenr)
653 {
654 struct backref_cache *cache = &rc->backref_cache;
655 struct btrfs_path *path1; /* For searching extent root */
656 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
657 struct extent_buffer *eb;
658 struct btrfs_root *root;
659 struct backref_node *cur;
660 struct backref_node *upper;
661 struct backref_node *lower;
662 struct backref_node *node = NULL;
663 struct backref_node *exist = NULL;
664 struct backref_edge *edge;
665 struct rb_node *rb_node;
666 struct btrfs_key key;
667 unsigned long end;
668 unsigned long ptr;
669 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
670 LIST_HEAD(useless);
671 int cowonly;
672 int ret;
673 int err = 0;
674 bool need_check = true;
675
676 path1 = btrfs_alloc_path();
677 path2 = btrfs_alloc_path();
678 if (!path1 || !path2) {
679 err = -ENOMEM;
680 goto out;
681 }
682 path1->reada = READA_FORWARD;
683 path2->reada = READA_FORWARD;
684
685 node = alloc_backref_node(cache);
686 if (!node) {
687 err = -ENOMEM;
688 goto out;
689 }
690
691 node->bytenr = bytenr;
692 node->level = level;
693 node->lowest = 1;
694 cur = node;
695 again:
696 end = 0;
697 ptr = 0;
698 key.objectid = cur->bytenr;
699 key.type = BTRFS_METADATA_ITEM_KEY;
700 key.offset = (u64)-1;
701
702 path1->search_commit_root = 1;
703 path1->skip_locking = 1;
704 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
705 0, 0);
706 if (ret < 0) {
707 err = ret;
708 goto out;
709 }
710 ASSERT(ret);
711 ASSERT(path1->slots[0]);
712
713 path1->slots[0]--;
714
715 WARN_ON(cur->checked);
716 if (!list_empty(&cur->upper)) {
717 /*
718 * the backref was added previously when processing
719 * backref of type BTRFS_TREE_BLOCK_REF_KEY
720 */
721 ASSERT(list_is_singular(&cur->upper));
722 edge = list_entry(cur->upper.next, struct backref_edge,
723 list[LOWER]);
724 ASSERT(list_empty(&edge->list[UPPER]));
725 exist = edge->node[UPPER];
726 /*
727 * add the upper level block to pending list if we need
728 * check its backrefs
729 */
730 if (!exist->checked)
731 list_add_tail(&edge->list[UPPER], &list);
732 } else {
733 exist = NULL;
734 }
735
736 while (1) {
737 cond_resched();
738 eb = path1->nodes[0];
739
740 if (ptr >= end) {
741 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
742 ret = btrfs_next_leaf(rc->extent_root, path1);
743 if (ret < 0) {
744 err = ret;
745 goto out;
746 }
747 if (ret > 0)
748 break;
749 eb = path1->nodes[0];
750 }
751
752 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
753 if (key.objectid != cur->bytenr) {
754 WARN_ON(exist);
755 break;
756 }
757
758 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
759 key.type == BTRFS_METADATA_ITEM_KEY) {
760 ret = find_inline_backref(eb, path1->slots[0],
761 &ptr, &end);
762 if (ret)
763 goto next;
764 }
765 }
766
767 if (ptr < end) {
768 /* update key for inline back ref */
769 struct btrfs_extent_inline_ref *iref;
770 int type;
771 iref = (struct btrfs_extent_inline_ref *)ptr;
772 type = btrfs_get_extent_inline_ref_type(eb, iref,
773 BTRFS_REF_TYPE_BLOCK);
774 if (type == BTRFS_REF_TYPE_INVALID) {
775 err = -EUCLEAN;
776 goto out;
777 }
778 key.type = type;
779 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
780
781 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
782 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
783 }
784
785 /*
786 * Parent node found and matches current inline ref, no need to
787 * rebuild this node for this inline ref.
788 */
789 if (exist &&
790 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
791 exist->owner == key.offset) ||
792 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
793 exist->bytenr == key.offset))) {
794 exist = NULL;
795 goto next;
796 }
797
798 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
799 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
800 if (key.objectid == key.offset) {
801 /*
802 * Only root blocks of reloc trees use backref
803 * pointing to itself.
804 */
805 root = find_reloc_root(rc, cur->bytenr);
806 ASSERT(root);
807 cur->root = root;
808 break;
809 }
810
811 edge = alloc_backref_edge(cache);
812 if (!edge) {
813 err = -ENOMEM;
814 goto out;
815 }
816 rb_node = tree_search(&cache->rb_root, key.offset);
817 if (!rb_node) {
818 upper = alloc_backref_node(cache);
819 if (!upper) {
820 free_backref_edge(cache, edge);
821 err = -ENOMEM;
822 goto out;
823 }
824 upper->bytenr = key.offset;
825 upper->level = cur->level + 1;
826 /*
827 * backrefs for the upper level block isn't
828 * cached, add the block to pending list
829 */
830 list_add_tail(&edge->list[UPPER], &list);
831 } else {
832 upper = rb_entry(rb_node, struct backref_node,
833 rb_node);
834 ASSERT(upper->checked);
835 INIT_LIST_HEAD(&edge->list[UPPER]);
836 }
837 list_add_tail(&edge->list[LOWER], &cur->upper);
838 edge->node[LOWER] = cur;
839 edge->node[UPPER] = upper;
840
841 goto next;
842 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
843 err = -EINVAL;
844 btrfs_print_v0_err(rc->extent_root->fs_info);
845 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
846 NULL);
847 goto out;
848 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
849 goto next;
850 }
851
852 /*
853 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
854 * means the root objectid. We need to search the tree to get
855 * its parent bytenr.
856 */
857 root = read_fs_root(rc->extent_root->fs_info, key.offset);
858 if (IS_ERR(root)) {
859 err = PTR_ERR(root);
860 goto out;
861 }
862
863 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
864 cur->cowonly = 1;
865
866 if (btrfs_root_level(&root->root_item) == cur->level) {
867 /* tree root */
868 ASSERT(btrfs_root_bytenr(&root->root_item) ==
869 cur->bytenr);
870 if (should_ignore_root(root))
871 list_add(&cur->list, &useless);
872 else
873 cur->root = root;
874 break;
875 }
876
877 level = cur->level + 1;
878
879 /* Search the tree to find parent blocks referring the block. */
880 path2->search_commit_root = 1;
881 path2->skip_locking = 1;
882 path2->lowest_level = level;
883 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
884 path2->lowest_level = 0;
885 if (ret < 0) {
886 err = ret;
887 goto out;
888 }
889 if (ret > 0 && path2->slots[level] > 0)
890 path2->slots[level]--;
891
892 eb = path2->nodes[level];
893 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
894 cur->bytenr) {
895 btrfs_err(root->fs_info,
896 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
897 cur->bytenr, level - 1,
898 root->root_key.objectid,
899 node_key->objectid, node_key->type,
900 node_key->offset);
901 err = -ENOENT;
902 goto out;
903 }
904 lower = cur;
905 need_check = true;
906
907 /* Add all nodes and edges in the path */
908 for (; level < BTRFS_MAX_LEVEL; level++) {
909 if (!path2->nodes[level]) {
910 ASSERT(btrfs_root_bytenr(&root->root_item) ==
911 lower->bytenr);
912 if (should_ignore_root(root))
913 list_add(&lower->list, &useless);
914 else
915 lower->root = root;
916 break;
917 }
918
919 edge = alloc_backref_edge(cache);
920 if (!edge) {
921 err = -ENOMEM;
922 goto out;
923 }
924
925 eb = path2->nodes[level];
926 rb_node = tree_search(&cache->rb_root, eb->start);
927 if (!rb_node) {
928 upper = alloc_backref_node(cache);
929 if (!upper) {
930 free_backref_edge(cache, edge);
931 err = -ENOMEM;
932 goto out;
933 }
934 upper->bytenr = eb->start;
935 upper->owner = btrfs_header_owner(eb);
936 upper->level = lower->level + 1;
937 if (!test_bit(BTRFS_ROOT_REF_COWS,
938 &root->state))
939 upper->cowonly = 1;
940
941 /*
942 * if we know the block isn't shared
943 * we can void checking its backrefs.
944 */
945 if (btrfs_block_can_be_shared(root, eb))
946 upper->checked = 0;
947 else
948 upper->checked = 1;
949
950 /*
951 * add the block to pending list if we
952 * need check its backrefs, we only do this once
953 * while walking up a tree as we will catch
954 * anything else later on.
955 */
956 if (!upper->checked && need_check) {
957 need_check = false;
958 list_add_tail(&edge->list[UPPER],
959 &list);
960 } else {
961 if (upper->checked)
962 need_check = true;
963 INIT_LIST_HEAD(&edge->list[UPPER]);
964 }
965 } else {
966 upper = rb_entry(rb_node, struct backref_node,
967 rb_node);
968 ASSERT(upper->checked);
969 INIT_LIST_HEAD(&edge->list[UPPER]);
970 if (!upper->owner)
971 upper->owner = btrfs_header_owner(eb);
972 }
973 list_add_tail(&edge->list[LOWER], &lower->upper);
974 edge->node[LOWER] = lower;
975 edge->node[UPPER] = upper;
976
977 if (rb_node)
978 break;
979 lower = upper;
980 upper = NULL;
981 }
982 btrfs_release_path(path2);
983 next:
984 if (ptr < end) {
985 ptr += btrfs_extent_inline_ref_size(key.type);
986 if (ptr >= end) {
987 WARN_ON(ptr > end);
988 ptr = 0;
989 end = 0;
990 }
991 }
992 if (ptr >= end)
993 path1->slots[0]++;
994 }
995 btrfs_release_path(path1);
996
997 cur->checked = 1;
998 WARN_ON(exist);
999
1000 /* the pending list isn't empty, take the first block to process */
1001 if (!list_empty(&list)) {
1002 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1003 list_del_init(&edge->list[UPPER]);
1004 cur = edge->node[UPPER];
1005 goto again;
1006 }
1007
1008 /*
1009 * everything goes well, connect backref nodes and insert backref nodes
1010 * into the cache.
1011 */
1012 ASSERT(node->checked);
1013 cowonly = node->cowonly;
1014 if (!cowonly) {
1015 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1016 &node->rb_node);
1017 if (rb_node)
1018 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1019 list_add_tail(&node->lower, &cache->leaves);
1020 }
1021
1022 list_for_each_entry(edge, &node->upper, list[LOWER])
1023 list_add_tail(&edge->list[UPPER], &list);
1024
1025 while (!list_empty(&list)) {
1026 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1027 list_del_init(&edge->list[UPPER]);
1028 upper = edge->node[UPPER];
1029 if (upper->detached) {
1030 list_del(&edge->list[LOWER]);
1031 lower = edge->node[LOWER];
1032 free_backref_edge(cache, edge);
1033 if (list_empty(&lower->upper))
1034 list_add(&lower->list, &useless);
1035 continue;
1036 }
1037
1038 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1039 if (upper->lowest) {
1040 list_del_init(&upper->lower);
1041 upper->lowest = 0;
1042 }
1043
1044 list_add_tail(&edge->list[UPPER], &upper->lower);
1045 continue;
1046 }
1047
1048 if (!upper->checked) {
1049 /*
1050 * Still want to blow up for developers since this is a
1051 * logic bug.
1052 */
1053 ASSERT(0);
1054 err = -EINVAL;
1055 goto out;
1056 }
1057 if (cowonly != upper->cowonly) {
1058 ASSERT(0);
1059 err = -EINVAL;
1060 goto out;
1061 }
1062
1063 if (!cowonly) {
1064 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1065 &upper->rb_node);
1066 if (rb_node)
1067 backref_tree_panic(rb_node, -EEXIST,
1068 upper->bytenr);
1069 }
1070
1071 list_add_tail(&edge->list[UPPER], &upper->lower);
1072
1073 list_for_each_entry(edge, &upper->upper, list[LOWER])
1074 list_add_tail(&edge->list[UPPER], &list);
1075 }
1076 /*
1077 * process useless backref nodes. backref nodes for tree leaves
1078 * are deleted from the cache. backref nodes for upper level
1079 * tree blocks are left in the cache to avoid unnecessary backref
1080 * lookup.
1081 */
1082 while (!list_empty(&useless)) {
1083 upper = list_entry(useless.next, struct backref_node, list);
1084 list_del_init(&upper->list);
1085 ASSERT(list_empty(&upper->upper));
1086 if (upper == node)
1087 node = NULL;
1088 if (upper->lowest) {
1089 list_del_init(&upper->lower);
1090 upper->lowest = 0;
1091 }
1092 while (!list_empty(&upper->lower)) {
1093 edge = list_entry(upper->lower.next,
1094 struct backref_edge, list[UPPER]);
1095 list_del(&edge->list[UPPER]);
1096 list_del(&edge->list[LOWER]);
1097 lower = edge->node[LOWER];
1098 free_backref_edge(cache, edge);
1099
1100 if (list_empty(&lower->upper))
1101 list_add(&lower->list, &useless);
1102 }
1103 __mark_block_processed(rc, upper);
1104 if (upper->level > 0) {
1105 list_add(&upper->list, &cache->detached);
1106 upper->detached = 1;
1107 } else {
1108 rb_erase(&upper->rb_node, &cache->rb_root);
1109 free_backref_node(cache, upper);
1110 }
1111 }
1112 out:
1113 btrfs_free_path(path1);
1114 btrfs_free_path(path2);
1115 if (err) {
1116 while (!list_empty(&useless)) {
1117 lower = list_entry(useless.next,
1118 struct backref_node, list);
1119 list_del_init(&lower->list);
1120 }
1121 while (!list_empty(&list)) {
1122 edge = list_first_entry(&list, struct backref_edge,
1123 list[UPPER]);
1124 list_del(&edge->list[UPPER]);
1125 list_del(&edge->list[LOWER]);
1126 lower = edge->node[LOWER];
1127 upper = edge->node[UPPER];
1128 free_backref_edge(cache, edge);
1129
1130 /*
1131 * Lower is no longer linked to any upper backref nodes
1132 * and isn't in the cache, we can free it ourselves.
1133 */
1134 if (list_empty(&lower->upper) &&
1135 RB_EMPTY_NODE(&lower->rb_node))
1136 list_add(&lower->list, &useless);
1137
1138 if (!RB_EMPTY_NODE(&upper->rb_node))
1139 continue;
1140
1141 /* Add this guy's upper edges to the list to process */
1142 list_for_each_entry(edge, &upper->upper, list[LOWER])
1143 list_add_tail(&edge->list[UPPER], &list);
1144 if (list_empty(&upper->upper))
1145 list_add(&upper->list, &useless);
1146 }
1147
1148 while (!list_empty(&useless)) {
1149 lower = list_entry(useless.next,
1150 struct backref_node, list);
1151 list_del_init(&lower->list);
1152 if (lower == node)
1153 node = NULL;
1154 free_backref_node(cache, lower);
1155 }
1156
1157 free_backref_node(cache, node);
1158 return ERR_PTR(err);
1159 }
1160 ASSERT(!node || !node->detached);
1161 return node;
1162 }
1163
1164 /*
1165 * helper to add backref node for the newly created snapshot.
1166 * the backref node is created by cloning backref node that
1167 * corresponds to root of source tree
1168 */
1169 static int clone_backref_node(struct btrfs_trans_handle *trans,
1170 struct reloc_control *rc,
1171 struct btrfs_root *src,
1172 struct btrfs_root *dest)
1173 {
1174 struct btrfs_root *reloc_root = src->reloc_root;
1175 struct backref_cache *cache = &rc->backref_cache;
1176 struct backref_node *node = NULL;
1177 struct backref_node *new_node;
1178 struct backref_edge *edge;
1179 struct backref_edge *new_edge;
1180 struct rb_node *rb_node;
1181
1182 if (cache->last_trans > 0)
1183 update_backref_cache(trans, cache);
1184
1185 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1186 if (rb_node) {
1187 node = rb_entry(rb_node, struct backref_node, rb_node);
1188 if (node->detached)
1189 node = NULL;
1190 else
1191 BUG_ON(node->new_bytenr != reloc_root->node->start);
1192 }
1193
1194 if (!node) {
1195 rb_node = tree_search(&cache->rb_root,
1196 reloc_root->commit_root->start);
1197 if (rb_node) {
1198 node = rb_entry(rb_node, struct backref_node,
1199 rb_node);
1200 BUG_ON(node->detached);
1201 }
1202 }
1203
1204 if (!node)
1205 return 0;
1206
1207 new_node = alloc_backref_node(cache);
1208 if (!new_node)
1209 return -ENOMEM;
1210
1211 new_node->bytenr = dest->node->start;
1212 new_node->level = node->level;
1213 new_node->lowest = node->lowest;
1214 new_node->checked = 1;
1215 new_node->root = dest;
1216
1217 if (!node->lowest) {
1218 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1219 new_edge = alloc_backref_edge(cache);
1220 if (!new_edge)
1221 goto fail;
1222
1223 new_edge->node[UPPER] = new_node;
1224 new_edge->node[LOWER] = edge->node[LOWER];
1225 list_add_tail(&new_edge->list[UPPER],
1226 &new_node->lower);
1227 }
1228 } else {
1229 list_add_tail(&new_node->lower, &cache->leaves);
1230 }
1231
1232 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1233 &new_node->rb_node);
1234 if (rb_node)
1235 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1236
1237 if (!new_node->lowest) {
1238 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1239 list_add_tail(&new_edge->list[LOWER],
1240 &new_edge->node[LOWER]->upper);
1241 }
1242 }
1243 return 0;
1244 fail:
1245 while (!list_empty(&new_node->lower)) {
1246 new_edge = list_entry(new_node->lower.next,
1247 struct backref_edge, list[UPPER]);
1248 list_del(&new_edge->list[UPPER]);
1249 free_backref_edge(cache, new_edge);
1250 }
1251 free_backref_node(cache, new_node);
1252 return -ENOMEM;
1253 }
1254
1255 /*
1256 * helper to add 'address of tree root -> reloc tree' mapping
1257 */
1258 static int __must_check __add_reloc_root(struct btrfs_root *root)
1259 {
1260 struct btrfs_fs_info *fs_info = root->fs_info;
1261 struct rb_node *rb_node;
1262 struct mapping_node *node;
1263 struct reloc_control *rc = fs_info->reloc_ctl;
1264
1265 node = kmalloc(sizeof(*node), GFP_NOFS);
1266 if (!node)
1267 return -ENOMEM;
1268
1269 node->bytenr = root->node->start;
1270 node->data = root;
1271
1272 spin_lock(&rc->reloc_root_tree.lock);
1273 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1274 node->bytenr, &node->rb_node);
1275 spin_unlock(&rc->reloc_root_tree.lock);
1276 if (rb_node) {
1277 btrfs_panic(fs_info, -EEXIST,
1278 "Duplicate root found for start=%llu while inserting into relocation tree",
1279 node->bytenr);
1280 }
1281
1282 list_add_tail(&root->root_list, &rc->reloc_roots);
1283 return 0;
1284 }
1285
1286 /*
1287 * helper to delete the 'address of tree root -> reloc tree'
1288 * mapping
1289 */
1290 static void __del_reloc_root(struct btrfs_root *root)
1291 {
1292 struct btrfs_fs_info *fs_info = root->fs_info;
1293 struct rb_node *rb_node;
1294 struct mapping_node *node = NULL;
1295 struct reloc_control *rc = fs_info->reloc_ctl;
1296
1297 if (rc && root->node) {
1298 spin_lock(&rc->reloc_root_tree.lock);
1299 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1300 root->node->start);
1301 if (rb_node) {
1302 node = rb_entry(rb_node, struct mapping_node, rb_node);
1303 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1304 }
1305 spin_unlock(&rc->reloc_root_tree.lock);
1306 if (!node)
1307 return;
1308 BUG_ON((struct btrfs_root *)node->data != root);
1309 }
1310
1311 spin_lock(&fs_info->trans_lock);
1312 list_del_init(&root->root_list);
1313 spin_unlock(&fs_info->trans_lock);
1314 kfree(node);
1315 }
1316
1317 /*
1318 * helper to update the 'address of tree root -> reloc tree'
1319 * mapping
1320 */
1321 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1322 {
1323 struct btrfs_fs_info *fs_info = root->fs_info;
1324 struct rb_node *rb_node;
1325 struct mapping_node *node = NULL;
1326 struct reloc_control *rc = fs_info->reloc_ctl;
1327
1328 spin_lock(&rc->reloc_root_tree.lock);
1329 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1330 root->node->start);
1331 if (rb_node) {
1332 node = rb_entry(rb_node, struct mapping_node, rb_node);
1333 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1334 }
1335 spin_unlock(&rc->reloc_root_tree.lock);
1336
1337 if (!node)
1338 return 0;
1339 BUG_ON((struct btrfs_root *)node->data != root);
1340
1341 spin_lock(&rc->reloc_root_tree.lock);
1342 node->bytenr = new_bytenr;
1343 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1344 node->bytenr, &node->rb_node);
1345 spin_unlock(&rc->reloc_root_tree.lock);
1346 if (rb_node)
1347 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1348 return 0;
1349 }
1350
1351 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1352 struct btrfs_root *root, u64 objectid)
1353 {
1354 struct btrfs_fs_info *fs_info = root->fs_info;
1355 struct btrfs_root *reloc_root;
1356 struct extent_buffer *eb;
1357 struct btrfs_root_item *root_item;
1358 struct btrfs_key root_key;
1359 int ret;
1360
1361 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1362 BUG_ON(!root_item);
1363
1364 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1365 root_key.type = BTRFS_ROOT_ITEM_KEY;
1366 root_key.offset = objectid;
1367
1368 if (root->root_key.objectid == objectid) {
1369 u64 commit_root_gen;
1370
1371 /* called by btrfs_init_reloc_root */
1372 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1373 BTRFS_TREE_RELOC_OBJECTID);
1374 BUG_ON(ret);
1375 /*
1376 * Set the last_snapshot field to the generation of the commit
1377 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1378 * correctly (returns true) when the relocation root is created
1379 * either inside the critical section of a transaction commit
1380 * (through transaction.c:qgroup_account_snapshot()) and when
1381 * it's created before the transaction commit is started.
1382 */
1383 commit_root_gen = btrfs_header_generation(root->commit_root);
1384 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1385 } else {
1386 /*
1387 * called by btrfs_reloc_post_snapshot_hook.
1388 * the source tree is a reloc tree, all tree blocks
1389 * modified after it was created have RELOC flag
1390 * set in their headers. so it's OK to not update
1391 * the 'last_snapshot'.
1392 */
1393 ret = btrfs_copy_root(trans, root, root->node, &eb,
1394 BTRFS_TREE_RELOC_OBJECTID);
1395 BUG_ON(ret);
1396 }
1397
1398 memcpy(root_item, &root->root_item, sizeof(*root_item));
1399 btrfs_set_root_bytenr(root_item, eb->start);
1400 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1401 btrfs_set_root_generation(root_item, trans->transid);
1402
1403 if (root->root_key.objectid == objectid) {
1404 btrfs_set_root_refs(root_item, 0);
1405 memset(&root_item->drop_progress, 0,
1406 sizeof(struct btrfs_disk_key));
1407 root_item->drop_level = 0;
1408 }
1409
1410 btrfs_tree_unlock(eb);
1411 free_extent_buffer(eb);
1412
1413 ret = btrfs_insert_root(trans, fs_info->tree_root,
1414 &root_key, root_item);
1415 BUG_ON(ret);
1416 kfree(root_item);
1417
1418 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1419 BUG_ON(IS_ERR(reloc_root));
1420 reloc_root->last_trans = trans->transid;
1421 return reloc_root;
1422 }
1423
1424 /*
1425 * create reloc tree for a given fs tree. reloc tree is just a
1426 * snapshot of the fs tree with special root objectid.
1427 */
1428 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1429 struct btrfs_root *root)
1430 {
1431 struct btrfs_fs_info *fs_info = root->fs_info;
1432 struct btrfs_root *reloc_root;
1433 struct reloc_control *rc = fs_info->reloc_ctl;
1434 struct btrfs_block_rsv *rsv;
1435 int clear_rsv = 0;
1436 int ret;
1437
1438 /*
1439 * The subvolume has reloc tree but the swap is finished, no need to
1440 * create/update the dead reloc tree
1441 */
1442 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
1443 return 0;
1444
1445 if (root->reloc_root) {
1446 reloc_root = root->reloc_root;
1447 reloc_root->last_trans = trans->transid;
1448 return 0;
1449 }
1450
1451 if (!rc || !rc->create_reloc_tree ||
1452 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1453 return 0;
1454
1455 if (!trans->reloc_reserved) {
1456 rsv = trans->block_rsv;
1457 trans->block_rsv = rc->block_rsv;
1458 clear_rsv = 1;
1459 }
1460 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1461 if (clear_rsv)
1462 trans->block_rsv = rsv;
1463
1464 ret = __add_reloc_root(reloc_root);
1465 BUG_ON(ret < 0);
1466 root->reloc_root = reloc_root;
1467 return 0;
1468 }
1469
1470 /*
1471 * update root item of reloc tree
1472 */
1473 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1474 struct btrfs_root *root)
1475 {
1476 struct btrfs_fs_info *fs_info = root->fs_info;
1477 struct btrfs_root *reloc_root;
1478 struct btrfs_root_item *root_item;
1479 int ret;
1480
1481 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1482 !root->reloc_root)
1483 goto out;
1484
1485 reloc_root = root->reloc_root;
1486 root_item = &reloc_root->root_item;
1487
1488 /* root->reloc_root will stay until current relocation finished */
1489 if (fs_info->reloc_ctl->merge_reloc_tree &&
1490 btrfs_root_refs(root_item) == 0) {
1491 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1492 __del_reloc_root(reloc_root);
1493 }
1494
1495 if (reloc_root->commit_root != reloc_root->node) {
1496 btrfs_set_root_node(root_item, reloc_root->node);
1497 free_extent_buffer(reloc_root->commit_root);
1498 reloc_root->commit_root = btrfs_root_node(reloc_root);
1499 }
1500
1501 ret = btrfs_update_root(trans, fs_info->tree_root,
1502 &reloc_root->root_key, root_item);
1503 BUG_ON(ret);
1504
1505 out:
1506 return 0;
1507 }
1508
1509 /*
1510 * helper to find first cached inode with inode number >= objectid
1511 * in a subvolume
1512 */
1513 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1514 {
1515 struct rb_node *node;
1516 struct rb_node *prev;
1517 struct btrfs_inode *entry;
1518 struct inode *inode;
1519
1520 spin_lock(&root->inode_lock);
1521 again:
1522 node = root->inode_tree.rb_node;
1523 prev = NULL;
1524 while (node) {
1525 prev = node;
1526 entry = rb_entry(node, struct btrfs_inode, rb_node);
1527
1528 if (objectid < btrfs_ino(entry))
1529 node = node->rb_left;
1530 else if (objectid > btrfs_ino(entry))
1531 node = node->rb_right;
1532 else
1533 break;
1534 }
1535 if (!node) {
1536 while (prev) {
1537 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1538 if (objectid <= btrfs_ino(entry)) {
1539 node = prev;
1540 break;
1541 }
1542 prev = rb_next(prev);
1543 }
1544 }
1545 while (node) {
1546 entry = rb_entry(node, struct btrfs_inode, rb_node);
1547 inode = igrab(&entry->vfs_inode);
1548 if (inode) {
1549 spin_unlock(&root->inode_lock);
1550 return inode;
1551 }
1552
1553 objectid = btrfs_ino(entry) + 1;
1554 if (cond_resched_lock(&root->inode_lock))
1555 goto again;
1556
1557 node = rb_next(node);
1558 }
1559 spin_unlock(&root->inode_lock);
1560 return NULL;
1561 }
1562
1563 static int in_block_group(u64 bytenr, struct btrfs_block_group *block_group)
1564 {
1565 if (bytenr >= block_group->start &&
1566 bytenr < block_group->start + block_group->length)
1567 return 1;
1568 return 0;
1569 }
1570
1571 /*
1572 * get new location of data
1573 */
1574 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1575 u64 bytenr, u64 num_bytes)
1576 {
1577 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1578 struct btrfs_path *path;
1579 struct btrfs_file_extent_item *fi;
1580 struct extent_buffer *leaf;
1581 int ret;
1582
1583 path = btrfs_alloc_path();
1584 if (!path)
1585 return -ENOMEM;
1586
1587 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1588 ret = btrfs_lookup_file_extent(NULL, root, path,
1589 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1590 if (ret < 0)
1591 goto out;
1592 if (ret > 0) {
1593 ret = -ENOENT;
1594 goto out;
1595 }
1596
1597 leaf = path->nodes[0];
1598 fi = btrfs_item_ptr(leaf, path->slots[0],
1599 struct btrfs_file_extent_item);
1600
1601 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1602 btrfs_file_extent_compression(leaf, fi) ||
1603 btrfs_file_extent_encryption(leaf, fi) ||
1604 btrfs_file_extent_other_encoding(leaf, fi));
1605
1606 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1607 ret = -EINVAL;
1608 goto out;
1609 }
1610
1611 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1612 ret = 0;
1613 out:
1614 btrfs_free_path(path);
1615 return ret;
1616 }
1617
1618 /*
1619 * update file extent items in the tree leaf to point to
1620 * the new locations.
1621 */
1622 static noinline_for_stack
1623 int replace_file_extents(struct btrfs_trans_handle *trans,
1624 struct reloc_control *rc,
1625 struct btrfs_root *root,
1626 struct extent_buffer *leaf)
1627 {
1628 struct btrfs_fs_info *fs_info = root->fs_info;
1629 struct btrfs_key key;
1630 struct btrfs_file_extent_item *fi;
1631 struct inode *inode = NULL;
1632 u64 parent;
1633 u64 bytenr;
1634 u64 new_bytenr = 0;
1635 u64 num_bytes;
1636 u64 end;
1637 u32 nritems;
1638 u32 i;
1639 int ret = 0;
1640 int first = 1;
1641 int dirty = 0;
1642
1643 if (rc->stage != UPDATE_DATA_PTRS)
1644 return 0;
1645
1646 /* reloc trees always use full backref */
1647 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1648 parent = leaf->start;
1649 else
1650 parent = 0;
1651
1652 nritems = btrfs_header_nritems(leaf);
1653 for (i = 0; i < nritems; i++) {
1654 struct btrfs_ref ref = { 0 };
1655
1656 cond_resched();
1657 btrfs_item_key_to_cpu(leaf, &key, i);
1658 if (key.type != BTRFS_EXTENT_DATA_KEY)
1659 continue;
1660 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1661 if (btrfs_file_extent_type(leaf, fi) ==
1662 BTRFS_FILE_EXTENT_INLINE)
1663 continue;
1664 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1665 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1666 if (bytenr == 0)
1667 continue;
1668 if (!in_block_group(bytenr, rc->block_group))
1669 continue;
1670
1671 /*
1672 * if we are modifying block in fs tree, wait for readpage
1673 * to complete and drop the extent cache
1674 */
1675 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1676 if (first) {
1677 inode = find_next_inode(root, key.objectid);
1678 first = 0;
1679 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1680 btrfs_add_delayed_iput(inode);
1681 inode = find_next_inode(root, key.objectid);
1682 }
1683 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1684 end = key.offset +
1685 btrfs_file_extent_num_bytes(leaf, fi);
1686 WARN_ON(!IS_ALIGNED(key.offset,
1687 fs_info->sectorsize));
1688 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1689 end--;
1690 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1691 key.offset, end);
1692 if (!ret)
1693 continue;
1694
1695 btrfs_drop_extent_cache(BTRFS_I(inode),
1696 key.offset, end, 1);
1697 unlock_extent(&BTRFS_I(inode)->io_tree,
1698 key.offset, end);
1699 }
1700 }
1701
1702 ret = get_new_location(rc->data_inode, &new_bytenr,
1703 bytenr, num_bytes);
1704 if (ret) {
1705 /*
1706 * Don't have to abort since we've not changed anything
1707 * in the file extent yet.
1708 */
1709 break;
1710 }
1711
1712 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1713 dirty = 1;
1714
1715 key.offset -= btrfs_file_extent_offset(leaf, fi);
1716 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1717 num_bytes, parent);
1718 ref.real_root = root->root_key.objectid;
1719 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1720 key.objectid, key.offset);
1721 ret = btrfs_inc_extent_ref(trans, &ref);
1722 if (ret) {
1723 btrfs_abort_transaction(trans, ret);
1724 break;
1725 }
1726
1727 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1728 num_bytes, parent);
1729 ref.real_root = root->root_key.objectid;
1730 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1731 key.objectid, key.offset);
1732 ret = btrfs_free_extent(trans, &ref);
1733 if (ret) {
1734 btrfs_abort_transaction(trans, ret);
1735 break;
1736 }
1737 }
1738 if (dirty)
1739 btrfs_mark_buffer_dirty(leaf);
1740 if (inode)
1741 btrfs_add_delayed_iput(inode);
1742 return ret;
1743 }
1744
1745 static noinline_for_stack
1746 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1747 struct btrfs_path *path, int level)
1748 {
1749 struct btrfs_disk_key key1;
1750 struct btrfs_disk_key key2;
1751 btrfs_node_key(eb, &key1, slot);
1752 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1753 return memcmp(&key1, &key2, sizeof(key1));
1754 }
1755
1756 /*
1757 * try to replace tree blocks in fs tree with the new blocks
1758 * in reloc tree. tree blocks haven't been modified since the
1759 * reloc tree was create can be replaced.
1760 *
1761 * if a block was replaced, level of the block + 1 is returned.
1762 * if no block got replaced, 0 is returned. if there are other
1763 * errors, a negative error number is returned.
1764 */
1765 static noinline_for_stack
1766 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1767 struct btrfs_root *dest, struct btrfs_root *src,
1768 struct btrfs_path *path, struct btrfs_key *next_key,
1769 int lowest_level, int max_level)
1770 {
1771 struct btrfs_fs_info *fs_info = dest->fs_info;
1772 struct extent_buffer *eb;
1773 struct extent_buffer *parent;
1774 struct btrfs_ref ref = { 0 };
1775 struct btrfs_key key;
1776 u64 old_bytenr;
1777 u64 new_bytenr;
1778 u64 old_ptr_gen;
1779 u64 new_ptr_gen;
1780 u64 last_snapshot;
1781 u32 blocksize;
1782 int cow = 0;
1783 int level;
1784 int ret;
1785 int slot;
1786
1787 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1788 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1789
1790 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1791 again:
1792 slot = path->slots[lowest_level];
1793 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1794
1795 eb = btrfs_lock_root_node(dest);
1796 btrfs_set_lock_blocking_write(eb);
1797 level = btrfs_header_level(eb);
1798
1799 if (level < lowest_level) {
1800 btrfs_tree_unlock(eb);
1801 free_extent_buffer(eb);
1802 return 0;
1803 }
1804
1805 if (cow) {
1806 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1807 BUG_ON(ret);
1808 }
1809 btrfs_set_lock_blocking_write(eb);
1810
1811 if (next_key) {
1812 next_key->objectid = (u64)-1;
1813 next_key->type = (u8)-1;
1814 next_key->offset = (u64)-1;
1815 }
1816
1817 parent = eb;
1818 while (1) {
1819 struct btrfs_key first_key;
1820
1821 level = btrfs_header_level(parent);
1822 BUG_ON(level < lowest_level);
1823
1824 ret = btrfs_bin_search(parent, &key, level, &slot);
1825 if (ret < 0)
1826 break;
1827 if (ret && slot > 0)
1828 slot--;
1829
1830 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1831 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1832
1833 old_bytenr = btrfs_node_blockptr(parent, slot);
1834 blocksize = fs_info->nodesize;
1835 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1836 btrfs_node_key_to_cpu(parent, &first_key, slot);
1837
1838 if (level <= max_level) {
1839 eb = path->nodes[level];
1840 new_bytenr = btrfs_node_blockptr(eb,
1841 path->slots[level]);
1842 new_ptr_gen = btrfs_node_ptr_generation(eb,
1843 path->slots[level]);
1844 } else {
1845 new_bytenr = 0;
1846 new_ptr_gen = 0;
1847 }
1848
1849 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1850 ret = level;
1851 break;
1852 }
1853
1854 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1855 memcmp_node_keys(parent, slot, path, level)) {
1856 if (level <= lowest_level) {
1857 ret = 0;
1858 break;
1859 }
1860
1861 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1862 level - 1, &first_key);
1863 if (IS_ERR(eb)) {
1864 ret = PTR_ERR(eb);
1865 break;
1866 } else if (!extent_buffer_uptodate(eb)) {
1867 ret = -EIO;
1868 free_extent_buffer(eb);
1869 break;
1870 }
1871 btrfs_tree_lock(eb);
1872 if (cow) {
1873 ret = btrfs_cow_block(trans, dest, eb, parent,
1874 slot, &eb);
1875 BUG_ON(ret);
1876 }
1877 btrfs_set_lock_blocking_write(eb);
1878
1879 btrfs_tree_unlock(parent);
1880 free_extent_buffer(parent);
1881
1882 parent = eb;
1883 continue;
1884 }
1885
1886 if (!cow) {
1887 btrfs_tree_unlock(parent);
1888 free_extent_buffer(parent);
1889 cow = 1;
1890 goto again;
1891 }
1892
1893 btrfs_node_key_to_cpu(path->nodes[level], &key,
1894 path->slots[level]);
1895 btrfs_release_path(path);
1896
1897 path->lowest_level = level;
1898 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1899 path->lowest_level = 0;
1900 BUG_ON(ret);
1901
1902 /*
1903 * Info qgroup to trace both subtrees.
1904 *
1905 * We must trace both trees.
1906 * 1) Tree reloc subtree
1907 * If not traced, we will leak data numbers
1908 * 2) Fs subtree
1909 * If not traced, we will double count old data
1910 *
1911 * We don't scan the subtree right now, but only record
1912 * the swapped tree blocks.
1913 * The real subtree rescan is delayed until we have new
1914 * CoW on the subtree root node before transaction commit.
1915 */
1916 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1917 rc->block_group, parent, slot,
1918 path->nodes[level], path->slots[level],
1919 last_snapshot);
1920 if (ret < 0)
1921 break;
1922 /*
1923 * swap blocks in fs tree and reloc tree.
1924 */
1925 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1926 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1927 btrfs_mark_buffer_dirty(parent);
1928
1929 btrfs_set_node_blockptr(path->nodes[level],
1930 path->slots[level], old_bytenr);
1931 btrfs_set_node_ptr_generation(path->nodes[level],
1932 path->slots[level], old_ptr_gen);
1933 btrfs_mark_buffer_dirty(path->nodes[level]);
1934
1935 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1936 blocksize, path->nodes[level]->start);
1937 ref.skip_qgroup = true;
1938 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1939 ret = btrfs_inc_extent_ref(trans, &ref);
1940 BUG_ON(ret);
1941 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1942 blocksize, 0);
1943 ref.skip_qgroup = true;
1944 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1945 ret = btrfs_inc_extent_ref(trans, &ref);
1946 BUG_ON(ret);
1947
1948 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1949 blocksize, path->nodes[level]->start);
1950 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1951 ref.skip_qgroup = true;
1952 ret = btrfs_free_extent(trans, &ref);
1953 BUG_ON(ret);
1954
1955 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1956 blocksize, 0);
1957 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1958 ref.skip_qgroup = true;
1959 ret = btrfs_free_extent(trans, &ref);
1960 BUG_ON(ret);
1961
1962 btrfs_unlock_up_safe(path, 0);
1963
1964 ret = level;
1965 break;
1966 }
1967 btrfs_tree_unlock(parent);
1968 free_extent_buffer(parent);
1969 return ret;
1970 }
1971
1972 /*
1973 * helper to find next relocated block in reloc tree
1974 */
1975 static noinline_for_stack
1976 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1977 int *level)
1978 {
1979 struct extent_buffer *eb;
1980 int i;
1981 u64 last_snapshot;
1982 u32 nritems;
1983
1984 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1985
1986 for (i = 0; i < *level; i++) {
1987 free_extent_buffer(path->nodes[i]);
1988 path->nodes[i] = NULL;
1989 }
1990
1991 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1992 eb = path->nodes[i];
1993 nritems = btrfs_header_nritems(eb);
1994 while (path->slots[i] + 1 < nritems) {
1995 path->slots[i]++;
1996 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1997 last_snapshot)
1998 continue;
1999
2000 *level = i;
2001 return 0;
2002 }
2003 free_extent_buffer(path->nodes[i]);
2004 path->nodes[i] = NULL;
2005 }
2006 return 1;
2007 }
2008
2009 /*
2010 * walk down reloc tree to find relocated block of lowest level
2011 */
2012 static noinline_for_stack
2013 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2014 int *level)
2015 {
2016 struct btrfs_fs_info *fs_info = root->fs_info;
2017 struct extent_buffer *eb = NULL;
2018 int i;
2019 u64 bytenr;
2020 u64 ptr_gen = 0;
2021 u64 last_snapshot;
2022 u32 nritems;
2023
2024 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2025
2026 for (i = *level; i > 0; i--) {
2027 struct btrfs_key first_key;
2028
2029 eb = path->nodes[i];
2030 nritems = btrfs_header_nritems(eb);
2031 while (path->slots[i] < nritems) {
2032 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2033 if (ptr_gen > last_snapshot)
2034 break;
2035 path->slots[i]++;
2036 }
2037 if (path->slots[i] >= nritems) {
2038 if (i == *level)
2039 break;
2040 *level = i + 1;
2041 return 0;
2042 }
2043 if (i == 1) {
2044 *level = i;
2045 return 0;
2046 }
2047
2048 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2049 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2050 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2051 &first_key);
2052 if (IS_ERR(eb)) {
2053 return PTR_ERR(eb);
2054 } else if (!extent_buffer_uptodate(eb)) {
2055 free_extent_buffer(eb);
2056 return -EIO;
2057 }
2058 BUG_ON(btrfs_header_level(eb) != i - 1);
2059 path->nodes[i - 1] = eb;
2060 path->slots[i - 1] = 0;
2061 }
2062 return 1;
2063 }
2064
2065 /*
2066 * invalidate extent cache for file extents whose key in range of
2067 * [min_key, max_key)
2068 */
2069 static int invalidate_extent_cache(struct btrfs_root *root,
2070 struct btrfs_key *min_key,
2071 struct btrfs_key *max_key)
2072 {
2073 struct btrfs_fs_info *fs_info = root->fs_info;
2074 struct inode *inode = NULL;
2075 u64 objectid;
2076 u64 start, end;
2077 u64 ino;
2078
2079 objectid = min_key->objectid;
2080 while (1) {
2081 cond_resched();
2082 iput(inode);
2083
2084 if (objectid > max_key->objectid)
2085 break;
2086
2087 inode = find_next_inode(root, objectid);
2088 if (!inode)
2089 break;
2090 ino = btrfs_ino(BTRFS_I(inode));
2091
2092 if (ino > max_key->objectid) {
2093 iput(inode);
2094 break;
2095 }
2096
2097 objectid = ino + 1;
2098 if (!S_ISREG(inode->i_mode))
2099 continue;
2100
2101 if (unlikely(min_key->objectid == ino)) {
2102 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2103 continue;
2104 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2105 start = 0;
2106 else {
2107 start = min_key->offset;
2108 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2109 }
2110 } else {
2111 start = 0;
2112 }
2113
2114 if (unlikely(max_key->objectid == ino)) {
2115 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2116 continue;
2117 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2118 end = (u64)-1;
2119 } else {
2120 if (max_key->offset == 0)
2121 continue;
2122 end = max_key->offset;
2123 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2124 end--;
2125 }
2126 } else {
2127 end = (u64)-1;
2128 }
2129
2130 /* the lock_extent waits for readpage to complete */
2131 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2132 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2133 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2134 }
2135 return 0;
2136 }
2137
2138 static int find_next_key(struct btrfs_path *path, int level,
2139 struct btrfs_key *key)
2140
2141 {
2142 while (level < BTRFS_MAX_LEVEL) {
2143 if (!path->nodes[level])
2144 break;
2145 if (path->slots[level] + 1 <
2146 btrfs_header_nritems(path->nodes[level])) {
2147 btrfs_node_key_to_cpu(path->nodes[level], key,
2148 path->slots[level] + 1);
2149 return 0;
2150 }
2151 level++;
2152 }
2153 return 1;
2154 }
2155
2156 /*
2157 * Insert current subvolume into reloc_control::dirty_subvol_roots
2158 */
2159 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2160 struct reloc_control *rc,
2161 struct btrfs_root *root)
2162 {
2163 struct btrfs_root *reloc_root = root->reloc_root;
2164 struct btrfs_root_item *reloc_root_item;
2165
2166 /* @root must be a subvolume tree root with a valid reloc tree */
2167 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2168 ASSERT(reloc_root);
2169
2170 reloc_root_item = &reloc_root->root_item;
2171 memset(&reloc_root_item->drop_progress, 0,
2172 sizeof(reloc_root_item->drop_progress));
2173 reloc_root_item->drop_level = 0;
2174 btrfs_set_root_refs(reloc_root_item, 0);
2175 btrfs_update_reloc_root(trans, root);
2176
2177 if (list_empty(&root->reloc_dirty_list)) {
2178 btrfs_grab_fs_root(root);
2179 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2180 }
2181 }
2182
2183 static int clean_dirty_subvols(struct reloc_control *rc)
2184 {
2185 struct btrfs_root *root;
2186 struct btrfs_root *next;
2187 int ret = 0;
2188 int ret2;
2189
2190 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2191 reloc_dirty_list) {
2192 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2193 /* Merged subvolume, cleanup its reloc root */
2194 struct btrfs_root *reloc_root = root->reloc_root;
2195
2196 list_del_init(&root->reloc_dirty_list);
2197 root->reloc_root = NULL;
2198 if (reloc_root) {
2199
2200 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2201 if (ret2 < 0 && !ret)
2202 ret = ret2;
2203 }
2204 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2205 btrfs_put_fs_root(root);
2206 } else {
2207 /* Orphan reloc tree, just clean it up */
2208 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2209 if (ret2 < 0 && !ret)
2210 ret = ret2;
2211 }
2212 }
2213 return ret;
2214 }
2215
2216 /*
2217 * merge the relocated tree blocks in reloc tree with corresponding
2218 * fs tree.
2219 */
2220 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2221 struct btrfs_root *root)
2222 {
2223 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2224 struct btrfs_key key;
2225 struct btrfs_key next_key;
2226 struct btrfs_trans_handle *trans = NULL;
2227 struct btrfs_root *reloc_root;
2228 struct btrfs_root_item *root_item;
2229 struct btrfs_path *path;
2230 struct extent_buffer *leaf;
2231 int level;
2232 int max_level;
2233 int replaced = 0;
2234 int ret;
2235 int err = 0;
2236 u32 min_reserved;
2237
2238 path = btrfs_alloc_path();
2239 if (!path)
2240 return -ENOMEM;
2241 path->reada = READA_FORWARD;
2242
2243 reloc_root = root->reloc_root;
2244 root_item = &reloc_root->root_item;
2245
2246 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2247 level = btrfs_root_level(root_item);
2248 atomic_inc(&reloc_root->node->refs);
2249 path->nodes[level] = reloc_root->node;
2250 path->slots[level] = 0;
2251 } else {
2252 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2253
2254 level = root_item->drop_level;
2255 BUG_ON(level == 0);
2256 path->lowest_level = level;
2257 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2258 path->lowest_level = 0;
2259 if (ret < 0) {
2260 btrfs_free_path(path);
2261 return ret;
2262 }
2263
2264 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2265 path->slots[level]);
2266 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2267
2268 btrfs_unlock_up_safe(path, 0);
2269 }
2270
2271 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2272 memset(&next_key, 0, sizeof(next_key));
2273
2274 while (1) {
2275 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2276 BTRFS_RESERVE_FLUSH_ALL);
2277 if (ret) {
2278 err = ret;
2279 goto out;
2280 }
2281 trans = btrfs_start_transaction(root, 0);
2282 if (IS_ERR(trans)) {
2283 err = PTR_ERR(trans);
2284 trans = NULL;
2285 goto out;
2286 }
2287 trans->block_rsv = rc->block_rsv;
2288
2289 replaced = 0;
2290 max_level = level;
2291
2292 ret = walk_down_reloc_tree(reloc_root, path, &level);
2293 if (ret < 0) {
2294 err = ret;
2295 goto out;
2296 }
2297 if (ret > 0)
2298 break;
2299
2300 if (!find_next_key(path, level, &key) &&
2301 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2302 ret = 0;
2303 } else {
2304 ret = replace_path(trans, rc, root, reloc_root, path,
2305 &next_key, level, max_level);
2306 }
2307 if (ret < 0) {
2308 err = ret;
2309 goto out;
2310 }
2311
2312 if (ret > 0) {
2313 level = ret;
2314 btrfs_node_key_to_cpu(path->nodes[level], &key,
2315 path->slots[level]);
2316 replaced = 1;
2317 }
2318
2319 ret = walk_up_reloc_tree(reloc_root, path, &level);
2320 if (ret > 0)
2321 break;
2322
2323 BUG_ON(level == 0);
2324 /*
2325 * save the merging progress in the drop_progress.
2326 * this is OK since root refs == 1 in this case.
2327 */
2328 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2329 path->slots[level]);
2330 root_item->drop_level = level;
2331
2332 btrfs_end_transaction_throttle(trans);
2333 trans = NULL;
2334
2335 btrfs_btree_balance_dirty(fs_info);
2336
2337 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2338 invalidate_extent_cache(root, &key, &next_key);
2339 }
2340
2341 /*
2342 * handle the case only one block in the fs tree need to be
2343 * relocated and the block is tree root.
2344 */
2345 leaf = btrfs_lock_root_node(root);
2346 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2347 btrfs_tree_unlock(leaf);
2348 free_extent_buffer(leaf);
2349 if (ret < 0)
2350 err = ret;
2351 out:
2352 btrfs_free_path(path);
2353
2354 if (err == 0)
2355 insert_dirty_subvol(trans, rc, root);
2356
2357 if (trans)
2358 btrfs_end_transaction_throttle(trans);
2359
2360 btrfs_btree_balance_dirty(fs_info);
2361
2362 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2363 invalidate_extent_cache(root, &key, &next_key);
2364
2365 return err;
2366 }
2367
2368 static noinline_for_stack
2369 int prepare_to_merge(struct reloc_control *rc, int err)
2370 {
2371 struct btrfs_root *root = rc->extent_root;
2372 struct btrfs_fs_info *fs_info = root->fs_info;
2373 struct btrfs_root *reloc_root;
2374 struct btrfs_trans_handle *trans;
2375 LIST_HEAD(reloc_roots);
2376 u64 num_bytes = 0;
2377 int ret;
2378
2379 mutex_lock(&fs_info->reloc_mutex);
2380 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2381 rc->merging_rsv_size += rc->nodes_relocated * 2;
2382 mutex_unlock(&fs_info->reloc_mutex);
2383
2384 again:
2385 if (!err) {
2386 num_bytes = rc->merging_rsv_size;
2387 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2388 BTRFS_RESERVE_FLUSH_ALL);
2389 if (ret)
2390 err = ret;
2391 }
2392
2393 trans = btrfs_join_transaction(rc->extent_root);
2394 if (IS_ERR(trans)) {
2395 if (!err)
2396 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2397 num_bytes);
2398 return PTR_ERR(trans);
2399 }
2400
2401 if (!err) {
2402 if (num_bytes != rc->merging_rsv_size) {
2403 btrfs_end_transaction(trans);
2404 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2405 num_bytes);
2406 goto again;
2407 }
2408 }
2409
2410 rc->merge_reloc_tree = 1;
2411
2412 while (!list_empty(&rc->reloc_roots)) {
2413 reloc_root = list_entry(rc->reloc_roots.next,
2414 struct btrfs_root, root_list);
2415 list_del_init(&reloc_root->root_list);
2416
2417 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2418 BUG_ON(IS_ERR(root));
2419 BUG_ON(root->reloc_root != reloc_root);
2420
2421 /*
2422 * set reference count to 1, so btrfs_recover_relocation
2423 * knows it should resumes merging
2424 */
2425 if (!err)
2426 btrfs_set_root_refs(&reloc_root->root_item, 1);
2427 btrfs_update_reloc_root(trans, root);
2428
2429 list_add(&reloc_root->root_list, &reloc_roots);
2430 }
2431
2432 list_splice(&reloc_roots, &rc->reloc_roots);
2433
2434 if (!err)
2435 btrfs_commit_transaction(trans);
2436 else
2437 btrfs_end_transaction(trans);
2438 return err;
2439 }
2440
2441 static noinline_for_stack
2442 void free_reloc_roots(struct list_head *list)
2443 {
2444 struct btrfs_root *reloc_root;
2445
2446 while (!list_empty(list)) {
2447 reloc_root = list_entry(list->next, struct btrfs_root,
2448 root_list);
2449 __del_reloc_root(reloc_root);
2450 free_extent_buffer(reloc_root->node);
2451 free_extent_buffer(reloc_root->commit_root);
2452 reloc_root->node = NULL;
2453 reloc_root->commit_root = NULL;
2454 }
2455 }
2456
2457 static noinline_for_stack
2458 void merge_reloc_roots(struct reloc_control *rc)
2459 {
2460 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2461 struct btrfs_root *root;
2462 struct btrfs_root *reloc_root;
2463 LIST_HEAD(reloc_roots);
2464 int found = 0;
2465 int ret = 0;
2466 again:
2467 root = rc->extent_root;
2468
2469 /*
2470 * this serializes us with btrfs_record_root_in_transaction,
2471 * we have to make sure nobody is in the middle of
2472 * adding their roots to the list while we are
2473 * doing this splice
2474 */
2475 mutex_lock(&fs_info->reloc_mutex);
2476 list_splice_init(&rc->reloc_roots, &reloc_roots);
2477 mutex_unlock(&fs_info->reloc_mutex);
2478
2479 while (!list_empty(&reloc_roots)) {
2480 found = 1;
2481 reloc_root = list_entry(reloc_roots.next,
2482 struct btrfs_root, root_list);
2483
2484 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2485 root = read_fs_root(fs_info,
2486 reloc_root->root_key.offset);
2487 BUG_ON(IS_ERR(root));
2488 BUG_ON(root->reloc_root != reloc_root);
2489
2490 ret = merge_reloc_root(rc, root);
2491 if (ret) {
2492 if (list_empty(&reloc_root->root_list))
2493 list_add_tail(&reloc_root->root_list,
2494 &reloc_roots);
2495 goto out;
2496 }
2497 } else {
2498 list_del_init(&reloc_root->root_list);
2499 /* Don't forget to queue this reloc root for cleanup */
2500 list_add_tail(&reloc_root->reloc_dirty_list,
2501 &rc->dirty_subvol_roots);
2502 }
2503 }
2504
2505 if (found) {
2506 found = 0;
2507 goto again;
2508 }
2509 out:
2510 if (ret) {
2511 btrfs_handle_fs_error(fs_info, ret, NULL);
2512 if (!list_empty(&reloc_roots))
2513 free_reloc_roots(&reloc_roots);
2514
2515 /* new reloc root may be added */
2516 mutex_lock(&fs_info->reloc_mutex);
2517 list_splice_init(&rc->reloc_roots, &reloc_roots);
2518 mutex_unlock(&fs_info->reloc_mutex);
2519 if (!list_empty(&reloc_roots))
2520 free_reloc_roots(&reloc_roots);
2521 }
2522
2523 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2524 }
2525
2526 static void free_block_list(struct rb_root *blocks)
2527 {
2528 struct tree_block *block;
2529 struct rb_node *rb_node;
2530 while ((rb_node = rb_first(blocks))) {
2531 block = rb_entry(rb_node, struct tree_block, rb_node);
2532 rb_erase(rb_node, blocks);
2533 kfree(block);
2534 }
2535 }
2536
2537 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2538 struct btrfs_root *reloc_root)
2539 {
2540 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2541 struct btrfs_root *root;
2542
2543 if (reloc_root->last_trans == trans->transid)
2544 return 0;
2545
2546 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2547 BUG_ON(IS_ERR(root));
2548 BUG_ON(root->reloc_root != reloc_root);
2549
2550 return btrfs_record_root_in_trans(trans, root);
2551 }
2552
2553 static noinline_for_stack
2554 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2555 struct reloc_control *rc,
2556 struct backref_node *node,
2557 struct backref_edge *edges[])
2558 {
2559 struct backref_node *next;
2560 struct btrfs_root *root;
2561 int index = 0;
2562
2563 next = node;
2564 while (1) {
2565 cond_resched();
2566 next = walk_up_backref(next, edges, &index);
2567 root = next->root;
2568 BUG_ON(!root);
2569 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2570
2571 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2572 record_reloc_root_in_trans(trans, root);
2573 break;
2574 }
2575
2576 btrfs_record_root_in_trans(trans, root);
2577 root = root->reloc_root;
2578
2579 if (next->new_bytenr != root->node->start) {
2580 BUG_ON(next->new_bytenr);
2581 BUG_ON(!list_empty(&next->list));
2582 next->new_bytenr = root->node->start;
2583 next->root = root;
2584 list_add_tail(&next->list,
2585 &rc->backref_cache.changed);
2586 __mark_block_processed(rc, next);
2587 break;
2588 }
2589
2590 WARN_ON(1);
2591 root = NULL;
2592 next = walk_down_backref(edges, &index);
2593 if (!next || next->level <= node->level)
2594 break;
2595 }
2596 if (!root)
2597 return NULL;
2598
2599 next = node;
2600 /* setup backref node path for btrfs_reloc_cow_block */
2601 while (1) {
2602 rc->backref_cache.path[next->level] = next;
2603 if (--index < 0)
2604 break;
2605 next = edges[index]->node[UPPER];
2606 }
2607 return root;
2608 }
2609
2610 /*
2611 * select a tree root for relocation. return NULL if the block
2612 * is reference counted. we should use do_relocation() in this
2613 * case. return a tree root pointer if the block isn't reference
2614 * counted. return -ENOENT if the block is root of reloc tree.
2615 */
2616 static noinline_for_stack
2617 struct btrfs_root *select_one_root(struct backref_node *node)
2618 {
2619 struct backref_node *next;
2620 struct btrfs_root *root;
2621 struct btrfs_root *fs_root = NULL;
2622 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2623 int index = 0;
2624
2625 next = node;
2626 while (1) {
2627 cond_resched();
2628 next = walk_up_backref(next, edges, &index);
2629 root = next->root;
2630 BUG_ON(!root);
2631
2632 /* no other choice for non-references counted tree */
2633 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2634 return root;
2635
2636 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2637 fs_root = root;
2638
2639 if (next != node)
2640 return NULL;
2641
2642 next = walk_down_backref(edges, &index);
2643 if (!next || next->level <= node->level)
2644 break;
2645 }
2646
2647 if (!fs_root)
2648 return ERR_PTR(-ENOENT);
2649 return fs_root;
2650 }
2651
2652 static noinline_for_stack
2653 u64 calcu_metadata_size(struct reloc_control *rc,
2654 struct backref_node *node, int reserve)
2655 {
2656 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2657 struct backref_node *next = node;
2658 struct backref_edge *edge;
2659 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2660 u64 num_bytes = 0;
2661 int index = 0;
2662
2663 BUG_ON(reserve && node->processed);
2664
2665 while (next) {
2666 cond_resched();
2667 while (1) {
2668 if (next->processed && (reserve || next != node))
2669 break;
2670
2671 num_bytes += fs_info->nodesize;
2672
2673 if (list_empty(&next->upper))
2674 break;
2675
2676 edge = list_entry(next->upper.next,
2677 struct backref_edge, list[LOWER]);
2678 edges[index++] = edge;
2679 next = edge->node[UPPER];
2680 }
2681 next = walk_down_backref(edges, &index);
2682 }
2683 return num_bytes;
2684 }
2685
2686 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2687 struct reloc_control *rc,
2688 struct backref_node *node)
2689 {
2690 struct btrfs_root *root = rc->extent_root;
2691 struct btrfs_fs_info *fs_info = root->fs_info;
2692 u64 num_bytes;
2693 int ret;
2694 u64 tmp;
2695
2696 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2697
2698 trans->block_rsv = rc->block_rsv;
2699 rc->reserved_bytes += num_bytes;
2700
2701 /*
2702 * We are under a transaction here so we can only do limited flushing.
2703 * If we get an enospc just kick back -EAGAIN so we know to drop the
2704 * transaction and try to refill when we can flush all the things.
2705 */
2706 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2707 BTRFS_RESERVE_FLUSH_LIMIT);
2708 if (ret) {
2709 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2710 while (tmp <= rc->reserved_bytes)
2711 tmp <<= 1;
2712 /*
2713 * only one thread can access block_rsv at this point,
2714 * so we don't need hold lock to protect block_rsv.
2715 * we expand more reservation size here to allow enough
2716 * space for relocation and we will return earlier in
2717 * enospc case.
2718 */
2719 rc->block_rsv->size = tmp + fs_info->nodesize *
2720 RELOCATION_RESERVED_NODES;
2721 return -EAGAIN;
2722 }
2723
2724 return 0;
2725 }
2726
2727 /*
2728 * relocate a block tree, and then update pointers in upper level
2729 * blocks that reference the block to point to the new location.
2730 *
2731 * if called by link_to_upper, the block has already been relocated.
2732 * in that case this function just updates pointers.
2733 */
2734 static int do_relocation(struct btrfs_trans_handle *trans,
2735 struct reloc_control *rc,
2736 struct backref_node *node,
2737 struct btrfs_key *key,
2738 struct btrfs_path *path, int lowest)
2739 {
2740 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2741 struct backref_node *upper;
2742 struct backref_edge *edge;
2743 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2744 struct btrfs_root *root;
2745 struct extent_buffer *eb;
2746 u32 blocksize;
2747 u64 bytenr;
2748 u64 generation;
2749 int slot;
2750 int ret;
2751 int err = 0;
2752
2753 BUG_ON(lowest && node->eb);
2754
2755 path->lowest_level = node->level + 1;
2756 rc->backref_cache.path[node->level] = node;
2757 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2758 struct btrfs_key first_key;
2759 struct btrfs_ref ref = { 0 };
2760
2761 cond_resched();
2762
2763 upper = edge->node[UPPER];
2764 root = select_reloc_root(trans, rc, upper, edges);
2765 BUG_ON(!root);
2766
2767 if (upper->eb && !upper->locked) {
2768 if (!lowest) {
2769 ret = btrfs_bin_search(upper->eb, key,
2770 upper->level, &slot);
2771 if (ret < 0) {
2772 err = ret;
2773 goto next;
2774 }
2775 BUG_ON(ret);
2776 bytenr = btrfs_node_blockptr(upper->eb, slot);
2777 if (node->eb->start == bytenr)
2778 goto next;
2779 }
2780 drop_node_buffer(upper);
2781 }
2782
2783 if (!upper->eb) {
2784 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2785 if (ret) {
2786 if (ret < 0)
2787 err = ret;
2788 else
2789 err = -ENOENT;
2790
2791 btrfs_release_path(path);
2792 break;
2793 }
2794
2795 if (!upper->eb) {
2796 upper->eb = path->nodes[upper->level];
2797 path->nodes[upper->level] = NULL;
2798 } else {
2799 BUG_ON(upper->eb != path->nodes[upper->level]);
2800 }
2801
2802 upper->locked = 1;
2803 path->locks[upper->level] = 0;
2804
2805 slot = path->slots[upper->level];
2806 btrfs_release_path(path);
2807 } else {
2808 ret = btrfs_bin_search(upper->eb, key, upper->level,
2809 &slot);
2810 if (ret < 0) {
2811 err = ret;
2812 goto next;
2813 }
2814 BUG_ON(ret);
2815 }
2816
2817 bytenr = btrfs_node_blockptr(upper->eb, slot);
2818 if (lowest) {
2819 if (bytenr != node->bytenr) {
2820 btrfs_err(root->fs_info,
2821 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2822 bytenr, node->bytenr, slot,
2823 upper->eb->start);
2824 err = -EIO;
2825 goto next;
2826 }
2827 } else {
2828 if (node->eb->start == bytenr)
2829 goto next;
2830 }
2831
2832 blocksize = root->fs_info->nodesize;
2833 generation = btrfs_node_ptr_generation(upper->eb, slot);
2834 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2835 eb = read_tree_block(fs_info, bytenr, generation,
2836 upper->level - 1, &first_key);
2837 if (IS_ERR(eb)) {
2838 err = PTR_ERR(eb);
2839 goto next;
2840 } else if (!extent_buffer_uptodate(eb)) {
2841 free_extent_buffer(eb);
2842 err = -EIO;
2843 goto next;
2844 }
2845 btrfs_tree_lock(eb);
2846 btrfs_set_lock_blocking_write(eb);
2847
2848 if (!node->eb) {
2849 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2850 slot, &eb);
2851 btrfs_tree_unlock(eb);
2852 free_extent_buffer(eb);
2853 if (ret < 0) {
2854 err = ret;
2855 goto next;
2856 }
2857 BUG_ON(node->eb != eb);
2858 } else {
2859 btrfs_set_node_blockptr(upper->eb, slot,
2860 node->eb->start);
2861 btrfs_set_node_ptr_generation(upper->eb, slot,
2862 trans->transid);
2863 btrfs_mark_buffer_dirty(upper->eb);
2864
2865 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2866 node->eb->start, blocksize,
2867 upper->eb->start);
2868 ref.real_root = root->root_key.objectid;
2869 btrfs_init_tree_ref(&ref, node->level,
2870 btrfs_header_owner(upper->eb));
2871 ret = btrfs_inc_extent_ref(trans, &ref);
2872 BUG_ON(ret);
2873
2874 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2875 BUG_ON(ret);
2876 }
2877 next:
2878 if (!upper->pending)
2879 drop_node_buffer(upper);
2880 else
2881 unlock_node_buffer(upper);
2882 if (err)
2883 break;
2884 }
2885
2886 if (!err && node->pending) {
2887 drop_node_buffer(node);
2888 list_move_tail(&node->list, &rc->backref_cache.changed);
2889 node->pending = 0;
2890 }
2891
2892 path->lowest_level = 0;
2893 BUG_ON(err == -ENOSPC);
2894 return err;
2895 }
2896
2897 static int link_to_upper(struct btrfs_trans_handle *trans,
2898 struct reloc_control *rc,
2899 struct backref_node *node,
2900 struct btrfs_path *path)
2901 {
2902 struct btrfs_key key;
2903
2904 btrfs_node_key_to_cpu(node->eb, &key, 0);
2905 return do_relocation(trans, rc, node, &key, path, 0);
2906 }
2907
2908 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2909 struct reloc_control *rc,
2910 struct btrfs_path *path, int err)
2911 {
2912 LIST_HEAD(list);
2913 struct backref_cache *cache = &rc->backref_cache;
2914 struct backref_node *node;
2915 int level;
2916 int ret;
2917
2918 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2919 while (!list_empty(&cache->pending[level])) {
2920 node = list_entry(cache->pending[level].next,
2921 struct backref_node, list);
2922 list_move_tail(&node->list, &list);
2923 BUG_ON(!node->pending);
2924
2925 if (!err) {
2926 ret = link_to_upper(trans, rc, node, path);
2927 if (ret < 0)
2928 err = ret;
2929 }
2930 }
2931 list_splice_init(&list, &cache->pending[level]);
2932 }
2933 return err;
2934 }
2935
2936 static void mark_block_processed(struct reloc_control *rc,
2937 u64 bytenr, u32 blocksize)
2938 {
2939 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2940 EXTENT_DIRTY);
2941 }
2942
2943 static void __mark_block_processed(struct reloc_control *rc,
2944 struct backref_node *node)
2945 {
2946 u32 blocksize;
2947 if (node->level == 0 ||
2948 in_block_group(node->bytenr, rc->block_group)) {
2949 blocksize = rc->extent_root->fs_info->nodesize;
2950 mark_block_processed(rc, node->bytenr, blocksize);
2951 }
2952 node->processed = 1;
2953 }
2954
2955 /*
2956 * mark a block and all blocks directly/indirectly reference the block
2957 * as processed.
2958 */
2959 static void update_processed_blocks(struct reloc_control *rc,
2960 struct backref_node *node)
2961 {
2962 struct backref_node *next = node;
2963 struct backref_edge *edge;
2964 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2965 int index = 0;
2966
2967 while (next) {
2968 cond_resched();
2969 while (1) {
2970 if (next->processed)
2971 break;
2972
2973 __mark_block_processed(rc, next);
2974
2975 if (list_empty(&next->upper))
2976 break;
2977
2978 edge = list_entry(next->upper.next,
2979 struct backref_edge, list[LOWER]);
2980 edges[index++] = edge;
2981 next = edge->node[UPPER];
2982 }
2983 next = walk_down_backref(edges, &index);
2984 }
2985 }
2986
2987 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2988 {
2989 u32 blocksize = rc->extent_root->fs_info->nodesize;
2990
2991 if (test_range_bit(&rc->processed_blocks, bytenr,
2992 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2993 return 1;
2994 return 0;
2995 }
2996
2997 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2998 struct tree_block *block)
2999 {
3000 struct extent_buffer *eb;
3001
3002 BUG_ON(block->key_ready);
3003 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
3004 block->level, NULL);
3005 if (IS_ERR(eb)) {
3006 return PTR_ERR(eb);
3007 } else if (!extent_buffer_uptodate(eb)) {
3008 free_extent_buffer(eb);
3009 return -EIO;
3010 }
3011 if (block->level == 0)
3012 btrfs_item_key_to_cpu(eb, &block->key, 0);
3013 else
3014 btrfs_node_key_to_cpu(eb, &block->key, 0);
3015 free_extent_buffer(eb);
3016 block->key_ready = 1;
3017 return 0;
3018 }
3019
3020 /*
3021 * helper function to relocate a tree block
3022 */
3023 static int relocate_tree_block(struct btrfs_trans_handle *trans,
3024 struct reloc_control *rc,
3025 struct backref_node *node,
3026 struct btrfs_key *key,
3027 struct btrfs_path *path)
3028 {
3029 struct btrfs_root *root;
3030 int ret = 0;
3031
3032 if (!node)
3033 return 0;
3034
3035 BUG_ON(node->processed);
3036 root = select_one_root(node);
3037 if (root == ERR_PTR(-ENOENT)) {
3038 update_processed_blocks(rc, node);
3039 goto out;
3040 }
3041
3042 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3043 ret = reserve_metadata_space(trans, rc, node);
3044 if (ret)
3045 goto out;
3046 }
3047
3048 if (root) {
3049 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3050 BUG_ON(node->new_bytenr);
3051 BUG_ON(!list_empty(&node->list));
3052 btrfs_record_root_in_trans(trans, root);
3053 root = root->reloc_root;
3054 node->new_bytenr = root->node->start;
3055 node->root = root;
3056 list_add_tail(&node->list, &rc->backref_cache.changed);
3057 } else {
3058 path->lowest_level = node->level;
3059 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3060 btrfs_release_path(path);
3061 if (ret > 0)
3062 ret = 0;
3063 }
3064 if (!ret)
3065 update_processed_blocks(rc, node);
3066 } else {
3067 ret = do_relocation(trans, rc, node, key, path, 1);
3068 }
3069 out:
3070 if (ret || node->level == 0 || node->cowonly)
3071 remove_backref_node(&rc->backref_cache, node);
3072 return ret;
3073 }
3074
3075 /*
3076 * relocate a list of blocks
3077 */
3078 static noinline_for_stack
3079 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3080 struct reloc_control *rc, struct rb_root *blocks)
3081 {
3082 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3083 struct backref_node *node;
3084 struct btrfs_path *path;
3085 struct tree_block *block;
3086 struct tree_block *next;
3087 int ret;
3088 int err = 0;
3089
3090 path = btrfs_alloc_path();
3091 if (!path) {
3092 err = -ENOMEM;
3093 goto out_free_blocks;
3094 }
3095
3096 /* Kick in readahead for tree blocks with missing keys */
3097 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3098 if (!block->key_ready)
3099 readahead_tree_block(fs_info, block->bytenr);
3100 }
3101
3102 /* Get first keys */
3103 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3104 if (!block->key_ready) {
3105 err = get_tree_block_key(fs_info, block);
3106 if (err)
3107 goto out_free_path;
3108 }
3109 }
3110
3111 /* Do tree relocation */
3112 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3113 node = build_backref_tree(rc, &block->key,
3114 block->level, block->bytenr);
3115 if (IS_ERR(node)) {
3116 err = PTR_ERR(node);
3117 goto out;
3118 }
3119
3120 ret = relocate_tree_block(trans, rc, node, &block->key,
3121 path);
3122 if (ret < 0) {
3123 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3124 err = ret;
3125 goto out;
3126 }
3127 }
3128 out:
3129 err = finish_pending_nodes(trans, rc, path, err);
3130
3131 out_free_path:
3132 btrfs_free_path(path);
3133 out_free_blocks:
3134 free_block_list(blocks);
3135 return err;
3136 }
3137
3138 static noinline_for_stack
3139 int prealloc_file_extent_cluster(struct inode *inode,
3140 struct file_extent_cluster *cluster)
3141 {
3142 u64 alloc_hint = 0;
3143 u64 start;
3144 u64 end;
3145 u64 offset = BTRFS_I(inode)->index_cnt;
3146 u64 num_bytes;
3147 int nr = 0;
3148 int ret = 0;
3149 u64 prealloc_start = cluster->start - offset;
3150 u64 prealloc_end = cluster->end - offset;
3151 u64 cur_offset;
3152 struct extent_changeset *data_reserved = NULL;
3153
3154 BUG_ON(cluster->start != cluster->boundary[0]);
3155 inode_lock(inode);
3156
3157 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3158 prealloc_end + 1 - prealloc_start);
3159 if (ret)
3160 goto out;
3161
3162 cur_offset = prealloc_start;
3163 while (nr < cluster->nr) {
3164 start = cluster->boundary[nr] - offset;
3165 if (nr + 1 < cluster->nr)
3166 end = cluster->boundary[nr + 1] - 1 - offset;
3167 else
3168 end = cluster->end - offset;
3169
3170 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3171 num_bytes = end + 1 - start;
3172 if (cur_offset < start)
3173 btrfs_free_reserved_data_space(inode, data_reserved,
3174 cur_offset, start - cur_offset);
3175 ret = btrfs_prealloc_file_range(inode, 0, start,
3176 num_bytes, num_bytes,
3177 end + 1, &alloc_hint);
3178 cur_offset = end + 1;
3179 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3180 if (ret)
3181 break;
3182 nr++;
3183 }
3184 if (cur_offset < prealloc_end)
3185 btrfs_free_reserved_data_space(inode, data_reserved,
3186 cur_offset, prealloc_end + 1 - cur_offset);
3187 out:
3188 inode_unlock(inode);
3189 extent_changeset_free(data_reserved);
3190 return ret;
3191 }
3192
3193 static noinline_for_stack
3194 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3195 u64 block_start)
3196 {
3197 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3198 struct extent_map *em;
3199 int ret = 0;
3200
3201 em = alloc_extent_map();
3202 if (!em)
3203 return -ENOMEM;
3204
3205 em->start = start;
3206 em->len = end + 1 - start;
3207 em->block_len = em->len;
3208 em->block_start = block_start;
3209 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3210
3211 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3212 while (1) {
3213 write_lock(&em_tree->lock);
3214 ret = add_extent_mapping(em_tree, em, 0);
3215 write_unlock(&em_tree->lock);
3216 if (ret != -EEXIST) {
3217 free_extent_map(em);
3218 break;
3219 }
3220 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3221 }
3222 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3223 return ret;
3224 }
3225
3226 static int relocate_file_extent_cluster(struct inode *inode,
3227 struct file_extent_cluster *cluster)
3228 {
3229 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3230 u64 page_start;
3231 u64 page_end;
3232 u64 offset = BTRFS_I(inode)->index_cnt;
3233 unsigned long index;
3234 unsigned long last_index;
3235 struct page *page;
3236 struct file_ra_state *ra;
3237 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3238 int nr = 0;
3239 int ret = 0;
3240
3241 if (!cluster->nr)
3242 return 0;
3243
3244 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3245 if (!ra)
3246 return -ENOMEM;
3247
3248 ret = prealloc_file_extent_cluster(inode, cluster);
3249 if (ret)
3250 goto out;
3251
3252 file_ra_state_init(ra, inode->i_mapping);
3253
3254 ret = setup_extent_mapping(inode, cluster->start - offset,
3255 cluster->end - offset, cluster->start);
3256 if (ret)
3257 goto out;
3258
3259 index = (cluster->start - offset) >> PAGE_SHIFT;
3260 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3261 while (index <= last_index) {
3262 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3263 PAGE_SIZE);
3264 if (ret)
3265 goto out;
3266
3267 page = find_lock_page(inode->i_mapping, index);
3268 if (!page) {
3269 page_cache_sync_readahead(inode->i_mapping,
3270 ra, NULL, index,
3271 last_index + 1 - index);
3272 page = find_or_create_page(inode->i_mapping, index,
3273 mask);
3274 if (!page) {
3275 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3276 PAGE_SIZE, true);
3277 btrfs_delalloc_release_extents(BTRFS_I(inode),
3278 PAGE_SIZE);
3279 ret = -ENOMEM;
3280 goto out;
3281 }
3282 }
3283
3284 if (PageReadahead(page)) {
3285 page_cache_async_readahead(inode->i_mapping,
3286 ra, NULL, page, index,
3287 last_index + 1 - index);
3288 }
3289
3290 if (!PageUptodate(page)) {
3291 btrfs_readpage(NULL, page);
3292 lock_page(page);
3293 if (!PageUptodate(page)) {
3294 unlock_page(page);
3295 put_page(page);
3296 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3297 PAGE_SIZE, true);
3298 btrfs_delalloc_release_extents(BTRFS_I(inode),
3299 PAGE_SIZE);
3300 ret = -EIO;
3301 goto out;
3302 }
3303 }
3304
3305 page_start = page_offset(page);
3306 page_end = page_start + PAGE_SIZE - 1;
3307
3308 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3309
3310 set_page_extent_mapped(page);
3311
3312 if (nr < cluster->nr &&
3313 page_start + offset == cluster->boundary[nr]) {
3314 set_extent_bits(&BTRFS_I(inode)->io_tree,
3315 page_start, page_end,
3316 EXTENT_BOUNDARY);
3317 nr++;
3318 }
3319
3320 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3321 NULL);
3322 if (ret) {
3323 unlock_page(page);
3324 put_page(page);
3325 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3326 PAGE_SIZE, true);
3327 btrfs_delalloc_release_extents(BTRFS_I(inode),
3328 PAGE_SIZE);
3329
3330 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3331 page_start, page_end,
3332 EXTENT_LOCKED | EXTENT_BOUNDARY);
3333 goto out;
3334
3335 }
3336 set_page_dirty(page);
3337
3338 unlock_extent(&BTRFS_I(inode)->io_tree,
3339 page_start, page_end);
3340 unlock_page(page);
3341 put_page(page);
3342
3343 index++;
3344 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
3345 balance_dirty_pages_ratelimited(inode->i_mapping);
3346 btrfs_throttle(fs_info);
3347 }
3348 WARN_ON(nr != cluster->nr);
3349 out:
3350 kfree(ra);
3351 return ret;
3352 }
3353
3354 static noinline_for_stack
3355 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3356 struct file_extent_cluster *cluster)
3357 {
3358 int ret;
3359
3360 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3361 ret = relocate_file_extent_cluster(inode, cluster);
3362 if (ret)
3363 return ret;
3364 cluster->nr = 0;
3365 }
3366
3367 if (!cluster->nr)
3368 cluster->start = extent_key->objectid;
3369 else
3370 BUG_ON(cluster->nr >= MAX_EXTENTS);
3371 cluster->end = extent_key->objectid + extent_key->offset - 1;
3372 cluster->boundary[cluster->nr] = extent_key->objectid;
3373 cluster->nr++;
3374
3375 if (cluster->nr >= MAX_EXTENTS) {
3376 ret = relocate_file_extent_cluster(inode, cluster);
3377 if (ret)
3378 return ret;
3379 cluster->nr = 0;
3380 }
3381 return 0;
3382 }
3383
3384 /*
3385 * helper to add a tree block to the list.
3386 * the major work is getting the generation and level of the block
3387 */
3388 static int add_tree_block(struct reloc_control *rc,
3389 struct btrfs_key *extent_key,
3390 struct btrfs_path *path,
3391 struct rb_root *blocks)
3392 {
3393 struct extent_buffer *eb;
3394 struct btrfs_extent_item *ei;
3395 struct btrfs_tree_block_info *bi;
3396 struct tree_block *block;
3397 struct rb_node *rb_node;
3398 u32 item_size;
3399 int level = -1;
3400 u64 generation;
3401
3402 eb = path->nodes[0];
3403 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3404
3405 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3406 item_size >= sizeof(*ei) + sizeof(*bi)) {
3407 ei = btrfs_item_ptr(eb, path->slots[0],
3408 struct btrfs_extent_item);
3409 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3410 bi = (struct btrfs_tree_block_info *)(ei + 1);
3411 level = btrfs_tree_block_level(eb, bi);
3412 } else {
3413 level = (int)extent_key->offset;
3414 }
3415 generation = btrfs_extent_generation(eb, ei);
3416 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3417 btrfs_print_v0_err(eb->fs_info);
3418 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3419 return -EINVAL;
3420 } else {
3421 BUG();
3422 }
3423
3424 btrfs_release_path(path);
3425
3426 BUG_ON(level == -1);
3427
3428 block = kmalloc(sizeof(*block), GFP_NOFS);
3429 if (!block)
3430 return -ENOMEM;
3431
3432 block->bytenr = extent_key->objectid;
3433 block->key.objectid = rc->extent_root->fs_info->nodesize;
3434 block->key.offset = generation;
3435 block->level = level;
3436 block->key_ready = 0;
3437
3438 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3439 if (rb_node)
3440 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3441
3442 return 0;
3443 }
3444
3445 /*
3446 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3447 */
3448 static int __add_tree_block(struct reloc_control *rc,
3449 u64 bytenr, u32 blocksize,
3450 struct rb_root *blocks)
3451 {
3452 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3453 struct btrfs_path *path;
3454 struct btrfs_key key;
3455 int ret;
3456 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3457
3458 if (tree_block_processed(bytenr, rc))
3459 return 0;
3460
3461 if (tree_search(blocks, bytenr))
3462 return 0;
3463
3464 path = btrfs_alloc_path();
3465 if (!path)
3466 return -ENOMEM;
3467 again:
3468 key.objectid = bytenr;
3469 if (skinny) {
3470 key.type = BTRFS_METADATA_ITEM_KEY;
3471 key.offset = (u64)-1;
3472 } else {
3473 key.type = BTRFS_EXTENT_ITEM_KEY;
3474 key.offset = blocksize;
3475 }
3476
3477 path->search_commit_root = 1;
3478 path->skip_locking = 1;
3479 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3480 if (ret < 0)
3481 goto out;
3482
3483 if (ret > 0 && skinny) {
3484 if (path->slots[0]) {
3485 path->slots[0]--;
3486 btrfs_item_key_to_cpu(path->nodes[0], &key,
3487 path->slots[0]);
3488 if (key.objectid == bytenr &&
3489 (key.type == BTRFS_METADATA_ITEM_KEY ||
3490 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3491 key.offset == blocksize)))
3492 ret = 0;
3493 }
3494
3495 if (ret) {
3496 skinny = false;
3497 btrfs_release_path(path);
3498 goto again;
3499 }
3500 }
3501 if (ret) {
3502 ASSERT(ret == 1);
3503 btrfs_print_leaf(path->nodes[0]);
3504 btrfs_err(fs_info,
3505 "tree block extent item (%llu) is not found in extent tree",
3506 bytenr);
3507 WARN_ON(1);
3508 ret = -EINVAL;
3509 goto out;
3510 }
3511
3512 ret = add_tree_block(rc, &key, path, blocks);
3513 out:
3514 btrfs_free_path(path);
3515 return ret;
3516 }
3517
3518 /*
3519 * helper to check if the block use full backrefs for pointers in it
3520 */
3521 static int block_use_full_backref(struct reloc_control *rc,
3522 struct extent_buffer *eb)
3523 {
3524 u64 flags;
3525 int ret;
3526
3527 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3528 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3529 return 1;
3530
3531 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3532 eb->start, btrfs_header_level(eb), 1,
3533 NULL, &flags);
3534 BUG_ON(ret);
3535
3536 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3537 ret = 1;
3538 else
3539 ret = 0;
3540 return ret;
3541 }
3542
3543 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3544 struct btrfs_block_group *block_group,
3545 struct inode *inode,
3546 u64 ino)
3547 {
3548 struct btrfs_key key;
3549 struct btrfs_root *root = fs_info->tree_root;
3550 struct btrfs_trans_handle *trans;
3551 int ret = 0;
3552
3553 if (inode)
3554 goto truncate;
3555
3556 key.objectid = ino;
3557 key.type = BTRFS_INODE_ITEM_KEY;
3558 key.offset = 0;
3559
3560 inode = btrfs_iget(fs_info->sb, &key, root);
3561 if (IS_ERR(inode))
3562 return -ENOENT;
3563
3564 truncate:
3565 ret = btrfs_check_trunc_cache_free_space(fs_info,
3566 &fs_info->global_block_rsv);
3567 if (ret)
3568 goto out;
3569
3570 trans = btrfs_join_transaction(root);
3571 if (IS_ERR(trans)) {
3572 ret = PTR_ERR(trans);
3573 goto out;
3574 }
3575
3576 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3577
3578 btrfs_end_transaction(trans);
3579 btrfs_btree_balance_dirty(fs_info);
3580 out:
3581 iput(inode);
3582 return ret;
3583 }
3584
3585 /*
3586 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3587 * this function scans fs tree to find blocks reference the data extent
3588 */
3589 static int find_data_references(struct reloc_control *rc,
3590 struct btrfs_key *extent_key,
3591 struct extent_buffer *leaf,
3592 struct btrfs_extent_data_ref *ref,
3593 struct rb_root *blocks)
3594 {
3595 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3596 struct btrfs_path *path;
3597 struct tree_block *block;
3598 struct btrfs_root *root;
3599 struct btrfs_file_extent_item *fi;
3600 struct rb_node *rb_node;
3601 struct btrfs_key key;
3602 u64 ref_root;
3603 u64 ref_objectid;
3604 u64 ref_offset;
3605 u32 ref_count;
3606 u32 nritems;
3607 int err = 0;
3608 int added = 0;
3609 int counted;
3610 int ret;
3611
3612 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3613 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3614 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3615 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3616
3617 /*
3618 * This is an extent belonging to the free space cache, lets just delete
3619 * it and redo the search.
3620 */
3621 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3622 ret = delete_block_group_cache(fs_info, rc->block_group,
3623 NULL, ref_objectid);
3624 if (ret != -ENOENT)
3625 return ret;
3626 ret = 0;
3627 }
3628
3629 path = btrfs_alloc_path();
3630 if (!path)
3631 return -ENOMEM;
3632 path->reada = READA_FORWARD;
3633
3634 root = read_fs_root(fs_info, ref_root);
3635 if (IS_ERR(root)) {
3636 err = PTR_ERR(root);
3637 goto out;
3638 }
3639
3640 key.objectid = ref_objectid;
3641 key.type = BTRFS_EXTENT_DATA_KEY;
3642 if (ref_offset > ((u64)-1 << 32))
3643 key.offset = 0;
3644 else
3645 key.offset = ref_offset;
3646
3647 path->search_commit_root = 1;
3648 path->skip_locking = 1;
3649 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3650 if (ret < 0) {
3651 err = ret;
3652 goto out;
3653 }
3654
3655 leaf = path->nodes[0];
3656 nritems = btrfs_header_nritems(leaf);
3657 /*
3658 * the references in tree blocks that use full backrefs
3659 * are not counted in
3660 */
3661 if (block_use_full_backref(rc, leaf))
3662 counted = 0;
3663 else
3664 counted = 1;
3665 rb_node = tree_search(blocks, leaf->start);
3666 if (rb_node) {
3667 if (counted)
3668 added = 1;
3669 else
3670 path->slots[0] = nritems;
3671 }
3672
3673 while (ref_count > 0) {
3674 while (path->slots[0] >= nritems) {
3675 ret = btrfs_next_leaf(root, path);
3676 if (ret < 0) {
3677 err = ret;
3678 goto out;
3679 }
3680 if (WARN_ON(ret > 0))
3681 goto out;
3682
3683 leaf = path->nodes[0];
3684 nritems = btrfs_header_nritems(leaf);
3685 added = 0;
3686
3687 if (block_use_full_backref(rc, leaf))
3688 counted = 0;
3689 else
3690 counted = 1;
3691 rb_node = tree_search(blocks, leaf->start);
3692 if (rb_node) {
3693 if (counted)
3694 added = 1;
3695 else
3696 path->slots[0] = nritems;
3697 }
3698 }
3699
3700 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3701 if (WARN_ON(key.objectid != ref_objectid ||
3702 key.type != BTRFS_EXTENT_DATA_KEY))
3703 break;
3704
3705 fi = btrfs_item_ptr(leaf, path->slots[0],
3706 struct btrfs_file_extent_item);
3707
3708 if (btrfs_file_extent_type(leaf, fi) ==
3709 BTRFS_FILE_EXTENT_INLINE)
3710 goto next;
3711
3712 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3713 extent_key->objectid)
3714 goto next;
3715
3716 key.offset -= btrfs_file_extent_offset(leaf, fi);
3717 if (key.offset != ref_offset)
3718 goto next;
3719
3720 if (counted)
3721 ref_count--;
3722 if (added)
3723 goto next;
3724
3725 if (!tree_block_processed(leaf->start, rc)) {
3726 block = kmalloc(sizeof(*block), GFP_NOFS);
3727 if (!block) {
3728 err = -ENOMEM;
3729 break;
3730 }
3731 block->bytenr = leaf->start;
3732 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3733 block->level = 0;
3734 block->key_ready = 1;
3735 rb_node = tree_insert(blocks, block->bytenr,
3736 &block->rb_node);
3737 if (rb_node)
3738 backref_tree_panic(rb_node, -EEXIST,
3739 block->bytenr);
3740 }
3741 if (counted)
3742 added = 1;
3743 else
3744 path->slots[0] = nritems;
3745 next:
3746 path->slots[0]++;
3747
3748 }
3749 out:
3750 btrfs_free_path(path);
3751 return err;
3752 }
3753
3754 /*
3755 * helper to find all tree blocks that reference a given data extent
3756 */
3757 static noinline_for_stack
3758 int add_data_references(struct reloc_control *rc,
3759 struct btrfs_key *extent_key,
3760 struct btrfs_path *path,
3761 struct rb_root *blocks)
3762 {
3763 struct btrfs_key key;
3764 struct extent_buffer *eb;
3765 struct btrfs_extent_data_ref *dref;
3766 struct btrfs_extent_inline_ref *iref;
3767 unsigned long ptr;
3768 unsigned long end;
3769 u32 blocksize = rc->extent_root->fs_info->nodesize;
3770 int ret = 0;
3771 int err = 0;
3772
3773 eb = path->nodes[0];
3774 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3775 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3776 ptr += sizeof(struct btrfs_extent_item);
3777
3778 while (ptr < end) {
3779 iref = (struct btrfs_extent_inline_ref *)ptr;
3780 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3781 BTRFS_REF_TYPE_DATA);
3782 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3783 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3784 ret = __add_tree_block(rc, key.offset, blocksize,
3785 blocks);
3786 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3787 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3788 ret = find_data_references(rc, extent_key,
3789 eb, dref, blocks);
3790 } else {
3791 ret = -EUCLEAN;
3792 btrfs_err(rc->extent_root->fs_info,
3793 "extent %llu slot %d has an invalid inline ref type",
3794 eb->start, path->slots[0]);
3795 }
3796 if (ret) {
3797 err = ret;
3798 goto out;
3799 }
3800 ptr += btrfs_extent_inline_ref_size(key.type);
3801 }
3802 WARN_ON(ptr > end);
3803
3804 while (1) {
3805 cond_resched();
3806 eb = path->nodes[0];
3807 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3808 ret = btrfs_next_leaf(rc->extent_root, path);
3809 if (ret < 0) {
3810 err = ret;
3811 break;
3812 }
3813 if (ret > 0)
3814 break;
3815 eb = path->nodes[0];
3816 }
3817
3818 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3819 if (key.objectid != extent_key->objectid)
3820 break;
3821
3822 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3823 ret = __add_tree_block(rc, key.offset, blocksize,
3824 blocks);
3825 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3826 dref = btrfs_item_ptr(eb, path->slots[0],
3827 struct btrfs_extent_data_ref);
3828 ret = find_data_references(rc, extent_key,
3829 eb, dref, blocks);
3830 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3831 btrfs_print_v0_err(eb->fs_info);
3832 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3833 ret = -EINVAL;
3834 } else {
3835 ret = 0;
3836 }
3837 if (ret) {
3838 err = ret;
3839 break;
3840 }
3841 path->slots[0]++;
3842 }
3843 out:
3844 btrfs_release_path(path);
3845 if (err)
3846 free_block_list(blocks);
3847 return err;
3848 }
3849
3850 /*
3851 * helper to find next unprocessed extent
3852 */
3853 static noinline_for_stack
3854 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3855 struct btrfs_key *extent_key)
3856 {
3857 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3858 struct btrfs_key key;
3859 struct extent_buffer *leaf;
3860 u64 start, end, last;
3861 int ret;
3862
3863 last = rc->block_group->start + rc->block_group->length;
3864 while (1) {
3865 cond_resched();
3866 if (rc->search_start >= last) {
3867 ret = 1;
3868 break;
3869 }
3870
3871 key.objectid = rc->search_start;
3872 key.type = BTRFS_EXTENT_ITEM_KEY;
3873 key.offset = 0;
3874
3875 path->search_commit_root = 1;
3876 path->skip_locking = 1;
3877 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3878 0, 0);
3879 if (ret < 0)
3880 break;
3881 next:
3882 leaf = path->nodes[0];
3883 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3884 ret = btrfs_next_leaf(rc->extent_root, path);
3885 if (ret != 0)
3886 break;
3887 leaf = path->nodes[0];
3888 }
3889
3890 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3891 if (key.objectid >= last) {
3892 ret = 1;
3893 break;
3894 }
3895
3896 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3897 key.type != BTRFS_METADATA_ITEM_KEY) {
3898 path->slots[0]++;
3899 goto next;
3900 }
3901
3902 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3903 key.objectid + key.offset <= rc->search_start) {
3904 path->slots[0]++;
3905 goto next;
3906 }
3907
3908 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3909 key.objectid + fs_info->nodesize <=
3910 rc->search_start) {
3911 path->slots[0]++;
3912 goto next;
3913 }
3914
3915 ret = find_first_extent_bit(&rc->processed_blocks,
3916 key.objectid, &start, &end,
3917 EXTENT_DIRTY, NULL);
3918
3919 if (ret == 0 && start <= key.objectid) {
3920 btrfs_release_path(path);
3921 rc->search_start = end + 1;
3922 } else {
3923 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3924 rc->search_start = key.objectid + key.offset;
3925 else
3926 rc->search_start = key.objectid +
3927 fs_info->nodesize;
3928 memcpy(extent_key, &key, sizeof(key));
3929 return 0;
3930 }
3931 }
3932 btrfs_release_path(path);
3933 return ret;
3934 }
3935
3936 static void set_reloc_control(struct reloc_control *rc)
3937 {
3938 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3939
3940 mutex_lock(&fs_info->reloc_mutex);
3941 fs_info->reloc_ctl = rc;
3942 mutex_unlock(&fs_info->reloc_mutex);
3943 }
3944
3945 static void unset_reloc_control(struct reloc_control *rc)
3946 {
3947 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3948
3949 mutex_lock(&fs_info->reloc_mutex);
3950 fs_info->reloc_ctl = NULL;
3951 mutex_unlock(&fs_info->reloc_mutex);
3952 }
3953
3954 static int check_extent_flags(u64 flags)
3955 {
3956 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3957 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3958 return 1;
3959 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3960 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3961 return 1;
3962 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3963 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3964 return 1;
3965 return 0;
3966 }
3967
3968 static noinline_for_stack
3969 int prepare_to_relocate(struct reloc_control *rc)
3970 {
3971 struct btrfs_trans_handle *trans;
3972 int ret;
3973
3974 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3975 BTRFS_BLOCK_RSV_TEMP);
3976 if (!rc->block_rsv)
3977 return -ENOMEM;
3978
3979 memset(&rc->cluster, 0, sizeof(rc->cluster));
3980 rc->search_start = rc->block_group->start;
3981 rc->extents_found = 0;
3982 rc->nodes_relocated = 0;
3983 rc->merging_rsv_size = 0;
3984 rc->reserved_bytes = 0;
3985 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3986 RELOCATION_RESERVED_NODES;
3987 ret = btrfs_block_rsv_refill(rc->extent_root,
3988 rc->block_rsv, rc->block_rsv->size,
3989 BTRFS_RESERVE_FLUSH_ALL);
3990 if (ret)
3991 return ret;
3992
3993 rc->create_reloc_tree = 1;
3994 set_reloc_control(rc);
3995
3996 trans = btrfs_join_transaction(rc->extent_root);
3997 if (IS_ERR(trans)) {
3998 unset_reloc_control(rc);
3999 /*
4000 * extent tree is not a ref_cow tree and has no reloc_root to
4001 * cleanup. And callers are responsible to free the above
4002 * block rsv.
4003 */
4004 return PTR_ERR(trans);
4005 }
4006 btrfs_commit_transaction(trans);
4007 return 0;
4008 }
4009
4010 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4011 {
4012 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4013 struct rb_root blocks = RB_ROOT;
4014 struct btrfs_key key;
4015 struct btrfs_trans_handle *trans = NULL;
4016 struct btrfs_path *path;
4017 struct btrfs_extent_item *ei;
4018 u64 flags;
4019 u32 item_size;
4020 int ret;
4021 int err = 0;
4022 int progress = 0;
4023
4024 path = btrfs_alloc_path();
4025 if (!path)
4026 return -ENOMEM;
4027 path->reada = READA_FORWARD;
4028
4029 ret = prepare_to_relocate(rc);
4030 if (ret) {
4031 err = ret;
4032 goto out_free;
4033 }
4034
4035 while (1) {
4036 rc->reserved_bytes = 0;
4037 ret = btrfs_block_rsv_refill(rc->extent_root,
4038 rc->block_rsv, rc->block_rsv->size,
4039 BTRFS_RESERVE_FLUSH_ALL);
4040 if (ret) {
4041 err = ret;
4042 break;
4043 }
4044 progress++;
4045 trans = btrfs_start_transaction(rc->extent_root, 0);
4046 if (IS_ERR(trans)) {
4047 err = PTR_ERR(trans);
4048 trans = NULL;
4049 break;
4050 }
4051 restart:
4052 if (update_backref_cache(trans, &rc->backref_cache)) {
4053 btrfs_end_transaction(trans);
4054 trans = NULL;
4055 continue;
4056 }
4057
4058 ret = find_next_extent(rc, path, &key);
4059 if (ret < 0)
4060 err = ret;
4061 if (ret != 0)
4062 break;
4063
4064 rc->extents_found++;
4065
4066 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4067 struct btrfs_extent_item);
4068 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4069 if (item_size >= sizeof(*ei)) {
4070 flags = btrfs_extent_flags(path->nodes[0], ei);
4071 ret = check_extent_flags(flags);
4072 BUG_ON(ret);
4073 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4074 err = -EINVAL;
4075 btrfs_print_v0_err(trans->fs_info);
4076 btrfs_abort_transaction(trans, err);
4077 break;
4078 } else {
4079 BUG();
4080 }
4081
4082 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4083 ret = add_tree_block(rc, &key, path, &blocks);
4084 } else if (rc->stage == UPDATE_DATA_PTRS &&
4085 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4086 ret = add_data_references(rc, &key, path, &blocks);
4087 } else {
4088 btrfs_release_path(path);
4089 ret = 0;
4090 }
4091 if (ret < 0) {
4092 err = ret;
4093 break;
4094 }
4095
4096 if (!RB_EMPTY_ROOT(&blocks)) {
4097 ret = relocate_tree_blocks(trans, rc, &blocks);
4098 if (ret < 0) {
4099 /*
4100 * if we fail to relocate tree blocks, force to update
4101 * backref cache when committing transaction.
4102 */
4103 rc->backref_cache.last_trans = trans->transid - 1;
4104
4105 if (ret != -EAGAIN) {
4106 err = ret;
4107 break;
4108 }
4109 rc->extents_found--;
4110 rc->search_start = key.objectid;
4111 }
4112 }
4113
4114 btrfs_end_transaction_throttle(trans);
4115 btrfs_btree_balance_dirty(fs_info);
4116 trans = NULL;
4117
4118 if (rc->stage == MOVE_DATA_EXTENTS &&
4119 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4120 rc->found_file_extent = 1;
4121 ret = relocate_data_extent(rc->data_inode,
4122 &key, &rc->cluster);
4123 if (ret < 0) {
4124 err = ret;
4125 break;
4126 }
4127 }
4128 }
4129 if (trans && progress && err == -ENOSPC) {
4130 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4131 if (ret == 1) {
4132 err = 0;
4133 progress = 0;
4134 goto restart;
4135 }
4136 }
4137
4138 btrfs_release_path(path);
4139 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4140
4141 if (trans) {
4142 btrfs_end_transaction_throttle(trans);
4143 btrfs_btree_balance_dirty(fs_info);
4144 }
4145
4146 if (!err) {
4147 ret = relocate_file_extent_cluster(rc->data_inode,
4148 &rc->cluster);
4149 if (ret < 0)
4150 err = ret;
4151 }
4152
4153 rc->create_reloc_tree = 0;
4154 set_reloc_control(rc);
4155
4156 backref_cache_cleanup(&rc->backref_cache);
4157 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4158
4159 err = prepare_to_merge(rc, err);
4160
4161 merge_reloc_roots(rc);
4162
4163 rc->merge_reloc_tree = 0;
4164 unset_reloc_control(rc);
4165 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4166
4167 /* get rid of pinned extents */
4168 trans = btrfs_join_transaction(rc->extent_root);
4169 if (IS_ERR(trans)) {
4170 err = PTR_ERR(trans);
4171 goto out_free;
4172 }
4173 btrfs_commit_transaction(trans);
4174 ret = clean_dirty_subvols(rc);
4175 if (ret < 0 && !err)
4176 err = ret;
4177 out_free:
4178 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4179 btrfs_free_path(path);
4180 return err;
4181 }
4182
4183 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4184 struct btrfs_root *root, u64 objectid)
4185 {
4186 struct btrfs_path *path;
4187 struct btrfs_inode_item *item;
4188 struct extent_buffer *leaf;
4189 int ret;
4190
4191 path = btrfs_alloc_path();
4192 if (!path)
4193 return -ENOMEM;
4194
4195 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4196 if (ret)
4197 goto out;
4198
4199 leaf = path->nodes[0];
4200 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4201 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4202 btrfs_set_inode_generation(leaf, item, 1);
4203 btrfs_set_inode_size(leaf, item, 0);
4204 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4205 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4206 BTRFS_INODE_PREALLOC);
4207 btrfs_mark_buffer_dirty(leaf);
4208 out:
4209 btrfs_free_path(path);
4210 return ret;
4211 }
4212
4213 /*
4214 * helper to create inode for data relocation.
4215 * the inode is in data relocation tree and its link count is 0
4216 */
4217 static noinline_for_stack
4218 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4219 struct btrfs_block_group *group)
4220 {
4221 struct inode *inode = NULL;
4222 struct btrfs_trans_handle *trans;
4223 struct btrfs_root *root;
4224 struct btrfs_key key;
4225 u64 objectid;
4226 int err = 0;
4227
4228 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4229 if (IS_ERR(root))
4230 return ERR_CAST(root);
4231
4232 trans = btrfs_start_transaction(root, 6);
4233 if (IS_ERR(trans))
4234 return ERR_CAST(trans);
4235
4236 err = btrfs_find_free_objectid(root, &objectid);
4237 if (err)
4238 goto out;
4239
4240 err = __insert_orphan_inode(trans, root, objectid);
4241 BUG_ON(err);
4242
4243 key.objectid = objectid;
4244 key.type = BTRFS_INODE_ITEM_KEY;
4245 key.offset = 0;
4246 inode = btrfs_iget(fs_info->sb, &key, root);
4247 BUG_ON(IS_ERR(inode));
4248 BTRFS_I(inode)->index_cnt = group->start;
4249
4250 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4251 out:
4252 btrfs_end_transaction(trans);
4253 btrfs_btree_balance_dirty(fs_info);
4254 if (err) {
4255 if (inode)
4256 iput(inode);
4257 inode = ERR_PTR(err);
4258 }
4259 return inode;
4260 }
4261
4262 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4263 {
4264 struct reloc_control *rc;
4265
4266 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4267 if (!rc)
4268 return NULL;
4269
4270 INIT_LIST_HEAD(&rc->reloc_roots);
4271 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4272 backref_cache_init(&rc->backref_cache);
4273 mapping_tree_init(&rc->reloc_root_tree);
4274 extent_io_tree_init(fs_info, &rc->processed_blocks,
4275 IO_TREE_RELOC_BLOCKS, NULL);
4276 return rc;
4277 }
4278
4279 /*
4280 * Print the block group being relocated
4281 */
4282 static void describe_relocation(struct btrfs_fs_info *fs_info,
4283 struct btrfs_block_group *block_group)
4284 {
4285 char buf[128] = {'\0'};
4286
4287 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4288
4289 btrfs_info(fs_info,
4290 "relocating block group %llu flags %s",
4291 block_group->start, buf);
4292 }
4293
4294 /*
4295 * function to relocate all extents in a block group.
4296 */
4297 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4298 {
4299 struct btrfs_block_group *bg;
4300 struct btrfs_root *extent_root = fs_info->extent_root;
4301 struct reloc_control *rc;
4302 struct inode *inode;
4303 struct btrfs_path *path;
4304 int ret;
4305 int rw = 0;
4306 int err = 0;
4307
4308 bg = btrfs_lookup_block_group(fs_info, group_start);
4309 if (!bg)
4310 return -ENOENT;
4311
4312 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4313 btrfs_put_block_group(bg);
4314 return -ETXTBSY;
4315 }
4316
4317 rc = alloc_reloc_control(fs_info);
4318 if (!rc) {
4319 btrfs_put_block_group(bg);
4320 return -ENOMEM;
4321 }
4322
4323 rc->extent_root = extent_root;
4324 rc->block_group = bg;
4325
4326 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4327 if (ret) {
4328 err = ret;
4329 goto out;
4330 }
4331 rw = 1;
4332
4333 path = btrfs_alloc_path();
4334 if (!path) {
4335 err = -ENOMEM;
4336 goto out;
4337 }
4338
4339 inode = lookup_free_space_inode(rc->block_group, path);
4340 btrfs_free_path(path);
4341
4342 if (!IS_ERR(inode))
4343 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4344 else
4345 ret = PTR_ERR(inode);
4346
4347 if (ret && ret != -ENOENT) {
4348 err = ret;
4349 goto out;
4350 }
4351
4352 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4353 if (IS_ERR(rc->data_inode)) {
4354 err = PTR_ERR(rc->data_inode);
4355 rc->data_inode = NULL;
4356 goto out;
4357 }
4358
4359 describe_relocation(fs_info, rc->block_group);
4360
4361 btrfs_wait_block_group_reservations(rc->block_group);
4362 btrfs_wait_nocow_writers(rc->block_group);
4363 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4364 rc->block_group->start,
4365 rc->block_group->length);
4366
4367 while (1) {
4368 mutex_lock(&fs_info->cleaner_mutex);
4369 ret = relocate_block_group(rc);
4370 mutex_unlock(&fs_info->cleaner_mutex);
4371 if (ret < 0)
4372 err = ret;
4373
4374 /*
4375 * We may have gotten ENOSPC after we already dirtied some
4376 * extents. If writeout happens while we're relocating a
4377 * different block group we could end up hitting the
4378 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4379 * btrfs_reloc_cow_block. Make sure we write everything out
4380 * properly so we don't trip over this problem, and then break
4381 * out of the loop if we hit an error.
4382 */
4383 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4384 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4385 (u64)-1);
4386 if (ret)
4387 err = ret;
4388 invalidate_mapping_pages(rc->data_inode->i_mapping,
4389 0, -1);
4390 rc->stage = UPDATE_DATA_PTRS;
4391 }
4392
4393 if (err < 0)
4394 goto out;
4395
4396 if (rc->extents_found == 0)
4397 break;
4398
4399 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4400
4401 }
4402
4403 WARN_ON(rc->block_group->pinned > 0);
4404 WARN_ON(rc->block_group->reserved > 0);
4405 WARN_ON(rc->block_group->used > 0);
4406 out:
4407 if (err && rw)
4408 btrfs_dec_block_group_ro(rc->block_group);
4409 iput(rc->data_inode);
4410 btrfs_put_block_group(rc->block_group);
4411 kfree(rc);
4412 return err;
4413 }
4414
4415 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4416 {
4417 struct btrfs_fs_info *fs_info = root->fs_info;
4418 struct btrfs_trans_handle *trans;
4419 int ret, err;
4420
4421 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4422 if (IS_ERR(trans))
4423 return PTR_ERR(trans);
4424
4425 memset(&root->root_item.drop_progress, 0,
4426 sizeof(root->root_item.drop_progress));
4427 root->root_item.drop_level = 0;
4428 btrfs_set_root_refs(&root->root_item, 0);
4429 ret = btrfs_update_root(trans, fs_info->tree_root,
4430 &root->root_key, &root->root_item);
4431
4432 err = btrfs_end_transaction(trans);
4433 if (err)
4434 return err;
4435 return ret;
4436 }
4437
4438 /*
4439 * recover relocation interrupted by system crash.
4440 *
4441 * this function resumes merging reloc trees with corresponding fs trees.
4442 * this is important for keeping the sharing of tree blocks
4443 */
4444 int btrfs_recover_relocation(struct btrfs_root *root)
4445 {
4446 struct btrfs_fs_info *fs_info = root->fs_info;
4447 LIST_HEAD(reloc_roots);
4448 struct btrfs_key key;
4449 struct btrfs_root *fs_root;
4450 struct btrfs_root *reloc_root;
4451 struct btrfs_path *path;
4452 struct extent_buffer *leaf;
4453 struct reloc_control *rc = NULL;
4454 struct btrfs_trans_handle *trans;
4455 int ret;
4456 int err = 0;
4457
4458 path = btrfs_alloc_path();
4459 if (!path)
4460 return -ENOMEM;
4461 path->reada = READA_BACK;
4462
4463 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4464 key.type = BTRFS_ROOT_ITEM_KEY;
4465 key.offset = (u64)-1;
4466
4467 while (1) {
4468 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4469 path, 0, 0);
4470 if (ret < 0) {
4471 err = ret;
4472 goto out;
4473 }
4474 if (ret > 0) {
4475 if (path->slots[0] == 0)
4476 break;
4477 path->slots[0]--;
4478 }
4479 leaf = path->nodes[0];
4480 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4481 btrfs_release_path(path);
4482
4483 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4484 key.type != BTRFS_ROOT_ITEM_KEY)
4485 break;
4486
4487 reloc_root = btrfs_read_fs_root(root, &key);
4488 if (IS_ERR(reloc_root)) {
4489 err = PTR_ERR(reloc_root);
4490 goto out;
4491 }
4492
4493 list_add(&reloc_root->root_list, &reloc_roots);
4494
4495 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4496 fs_root = read_fs_root(fs_info,
4497 reloc_root->root_key.offset);
4498 if (IS_ERR(fs_root)) {
4499 ret = PTR_ERR(fs_root);
4500 if (ret != -ENOENT) {
4501 err = ret;
4502 goto out;
4503 }
4504 ret = mark_garbage_root(reloc_root);
4505 if (ret < 0) {
4506 err = ret;
4507 goto out;
4508 }
4509 }
4510 }
4511
4512 if (key.offset == 0)
4513 break;
4514
4515 key.offset--;
4516 }
4517 btrfs_release_path(path);
4518
4519 if (list_empty(&reloc_roots))
4520 goto out;
4521
4522 rc = alloc_reloc_control(fs_info);
4523 if (!rc) {
4524 err = -ENOMEM;
4525 goto out;
4526 }
4527
4528 rc->extent_root = fs_info->extent_root;
4529
4530 set_reloc_control(rc);
4531
4532 trans = btrfs_join_transaction(rc->extent_root);
4533 if (IS_ERR(trans)) {
4534 unset_reloc_control(rc);
4535 err = PTR_ERR(trans);
4536 goto out_free;
4537 }
4538
4539 rc->merge_reloc_tree = 1;
4540
4541 while (!list_empty(&reloc_roots)) {
4542 reloc_root = list_entry(reloc_roots.next,
4543 struct btrfs_root, root_list);
4544 list_del(&reloc_root->root_list);
4545
4546 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4547 list_add_tail(&reloc_root->root_list,
4548 &rc->reloc_roots);
4549 continue;
4550 }
4551
4552 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4553 if (IS_ERR(fs_root)) {
4554 err = PTR_ERR(fs_root);
4555 list_add_tail(&reloc_root->root_list, &reloc_roots);
4556 goto out_free;
4557 }
4558
4559 err = __add_reloc_root(reloc_root);
4560 BUG_ON(err < 0); /* -ENOMEM or logic error */
4561 fs_root->reloc_root = reloc_root;
4562 }
4563
4564 err = btrfs_commit_transaction(trans);
4565 if (err)
4566 goto out_free;
4567
4568 merge_reloc_roots(rc);
4569
4570 unset_reloc_control(rc);
4571
4572 trans = btrfs_join_transaction(rc->extent_root);
4573 if (IS_ERR(trans)) {
4574 err = PTR_ERR(trans);
4575 goto out_free;
4576 }
4577 err = btrfs_commit_transaction(trans);
4578
4579 ret = clean_dirty_subvols(rc);
4580 if (ret < 0 && !err)
4581 err = ret;
4582 out_free:
4583 kfree(rc);
4584 out:
4585 if (!list_empty(&reloc_roots))
4586 free_reloc_roots(&reloc_roots);
4587
4588 btrfs_free_path(path);
4589
4590 if (err == 0) {
4591 /* cleanup orphan inode in data relocation tree */
4592 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4593 if (IS_ERR(fs_root))
4594 err = PTR_ERR(fs_root);
4595 else
4596 err = btrfs_orphan_cleanup(fs_root);
4597 }
4598 return err;
4599 }
4600
4601 /*
4602 * helper to add ordered checksum for data relocation.
4603 *
4604 * cloning checksum properly handles the nodatasum extents.
4605 * it also saves CPU time to re-calculate the checksum.
4606 */
4607 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4608 {
4609 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4610 struct btrfs_ordered_sum *sums;
4611 struct btrfs_ordered_extent *ordered;
4612 int ret;
4613 u64 disk_bytenr;
4614 u64 new_bytenr;
4615 LIST_HEAD(list);
4616
4617 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4618 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4619
4620 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4621 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4622 disk_bytenr + len - 1, &list, 0);
4623 if (ret)
4624 goto out;
4625
4626 while (!list_empty(&list)) {
4627 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4628 list_del_init(&sums->list);
4629
4630 /*
4631 * We need to offset the new_bytenr based on where the csum is.
4632 * We need to do this because we will read in entire prealloc
4633 * extents but we may have written to say the middle of the
4634 * prealloc extent, so we need to make sure the csum goes with
4635 * the right disk offset.
4636 *
4637 * We can do this because the data reloc inode refers strictly
4638 * to the on disk bytes, so we don't have to worry about
4639 * disk_len vs real len like with real inodes since it's all
4640 * disk length.
4641 */
4642 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4643 sums->bytenr = new_bytenr;
4644
4645 btrfs_add_ordered_sum(ordered, sums);
4646 }
4647 out:
4648 btrfs_put_ordered_extent(ordered);
4649 return ret;
4650 }
4651
4652 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4653 struct btrfs_root *root, struct extent_buffer *buf,
4654 struct extent_buffer *cow)
4655 {
4656 struct btrfs_fs_info *fs_info = root->fs_info;
4657 struct reloc_control *rc;
4658 struct backref_node *node;
4659 int first_cow = 0;
4660 int level;
4661 int ret = 0;
4662
4663 rc = fs_info->reloc_ctl;
4664 if (!rc)
4665 return 0;
4666
4667 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4668 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4669
4670 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4671 if (buf == root->node)
4672 __update_reloc_root(root, cow->start);
4673 }
4674
4675 level = btrfs_header_level(buf);
4676 if (btrfs_header_generation(buf) <=
4677 btrfs_root_last_snapshot(&root->root_item))
4678 first_cow = 1;
4679
4680 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4681 rc->create_reloc_tree) {
4682 WARN_ON(!first_cow && level == 0);
4683
4684 node = rc->backref_cache.path[level];
4685 BUG_ON(node->bytenr != buf->start &&
4686 node->new_bytenr != buf->start);
4687
4688 drop_node_buffer(node);
4689 atomic_inc(&cow->refs);
4690 node->eb = cow;
4691 node->new_bytenr = cow->start;
4692
4693 if (!node->pending) {
4694 list_move_tail(&node->list,
4695 &rc->backref_cache.pending[level]);
4696 node->pending = 1;
4697 }
4698
4699 if (first_cow)
4700 __mark_block_processed(rc, node);
4701
4702 if (first_cow && level > 0)
4703 rc->nodes_relocated += buf->len;
4704 }
4705
4706 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4707 ret = replace_file_extents(trans, rc, root, cow);
4708 return ret;
4709 }
4710
4711 /*
4712 * called before creating snapshot. it calculates metadata reservation
4713 * required for relocating tree blocks in the snapshot
4714 */
4715 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4716 u64 *bytes_to_reserve)
4717 {
4718 struct btrfs_root *root = pending->root;
4719 struct reloc_control *rc = root->fs_info->reloc_ctl;
4720
4721 if (!root->reloc_root || !rc)
4722 return;
4723
4724 if (!rc->merge_reloc_tree)
4725 return;
4726
4727 root = root->reloc_root;
4728 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4729 /*
4730 * relocation is in the stage of merging trees. the space
4731 * used by merging a reloc tree is twice the size of
4732 * relocated tree nodes in the worst case. half for cowing
4733 * the reloc tree, half for cowing the fs tree. the space
4734 * used by cowing the reloc tree will be freed after the
4735 * tree is dropped. if we create snapshot, cowing the fs
4736 * tree may use more space than it frees. so we need
4737 * reserve extra space.
4738 */
4739 *bytes_to_reserve += rc->nodes_relocated;
4740 }
4741
4742 /*
4743 * called after snapshot is created. migrate block reservation
4744 * and create reloc root for the newly created snapshot
4745 */
4746 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4747 struct btrfs_pending_snapshot *pending)
4748 {
4749 struct btrfs_root *root = pending->root;
4750 struct btrfs_root *reloc_root;
4751 struct btrfs_root *new_root;
4752 struct reloc_control *rc = root->fs_info->reloc_ctl;
4753 int ret;
4754
4755 if (!root->reloc_root || !rc)
4756 return 0;
4757
4758 rc = root->fs_info->reloc_ctl;
4759 rc->merging_rsv_size += rc->nodes_relocated;
4760
4761 if (rc->merge_reloc_tree) {
4762 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4763 rc->block_rsv,
4764 rc->nodes_relocated, true);
4765 if (ret)
4766 return ret;
4767 }
4768
4769 new_root = pending->snap;
4770 reloc_root = create_reloc_root(trans, root->reloc_root,
4771 new_root->root_key.objectid);
4772 if (IS_ERR(reloc_root))
4773 return PTR_ERR(reloc_root);
4774
4775 ret = __add_reloc_root(reloc_root);
4776 BUG_ON(ret < 0);
4777 new_root->reloc_root = reloc_root;
4778
4779 if (rc->create_reloc_tree)
4780 ret = clone_backref_node(trans, rc, root, reloc_root);
4781 return ret;
4782 }
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