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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 */
29struct tree_entry {
30 struct rb_node rb_node;
31 u64 bytenr;
32};
33
34/*
35 * present a tree block in the backref cache
36 */
37struct 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 */
81struct 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
90struct 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 */
117struct mapping_node {
118 struct rb_node rb_node;
119 u64 bytenr;
120 void *data;
121};
122
123struct mapping_tree {
124 struct rb_root rb_root;
125 spinlock_t lock;
126};
127
128/*
129 * present a tree block to process
130 */
131struct 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
141struct file_extent_cluster {
142 u64 start;
143 u64 end;
144 u64 boundary[MAX_EXTENTS];
145 unsigned int nr;
146};
147
148struct reloc_control {
149 /* block group to relocate */
150 struct btrfs_block_group_cache *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
189static void remove_backref_node(struct backref_cache *cache,
190 struct backref_node *node);
191static void __mark_block_processed(struct reloc_control *rc,
192 struct backref_node *node);
193
194static void mapping_tree_init(struct mapping_tree *tree)
195{
196 tree->rb_root = RB_ROOT;
197 spin_lock_init(&tree->lock);
198}
199
200static 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
211static 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
239static 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
254static 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
263static 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
273static 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
282static 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
306static 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
324static 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 */
340static 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 */
361static 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
385static 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
393static 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
402static 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 */
418static 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
456static 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 */
470static 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
521static 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 */
546static 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
563static 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
578static 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
593static noinline_for_stack
594int 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 */
649static noinline_for_stack
650struct 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;
695again:
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);
983next:
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 }
1112out:
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 */
1169static 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;
1244fail:
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 */
1258static 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 */
1290static 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 */
1321static 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
1351static 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 */
1428int 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 */
1473int 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
1505out:
1506 return 0;
1507}
1508
1509/*
1510 * helper to find first cached inode with inode number >= objectid
1511 * in a subvolume
1512 */
1513static 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);
1521again:
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
1563static int in_block_group(u64 bytenr,
1564 struct btrfs_block_group_cache *block_group)
1565{
1566 if (bytenr >= block_group->key.objectid &&
1567 bytenr < block_group->key.objectid + block_group->key.offset)
1568 return 1;
1569 return 0;
1570}
1571
1572/*
1573 * get new location of data
1574 */
1575static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1576 u64 bytenr, u64 num_bytes)
1577{
1578 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1579 struct btrfs_path *path;
1580 struct btrfs_file_extent_item *fi;
1581 struct extent_buffer *leaf;
1582 int ret;
1583
1584 path = btrfs_alloc_path();
1585 if (!path)
1586 return -ENOMEM;
1587
1588 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1589 ret = btrfs_lookup_file_extent(NULL, root, path,
1590 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1591 if (ret < 0)
1592 goto out;
1593 if (ret > 0) {
1594 ret = -ENOENT;
1595 goto out;
1596 }
1597
1598 leaf = path->nodes[0];
1599 fi = btrfs_item_ptr(leaf, path->slots[0],
1600 struct btrfs_file_extent_item);
1601
1602 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1603 btrfs_file_extent_compression(leaf, fi) ||
1604 btrfs_file_extent_encryption(leaf, fi) ||
1605 btrfs_file_extent_other_encoding(leaf, fi));
1606
1607 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1608 ret = -EINVAL;
1609 goto out;
1610 }
1611
1612 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1613 ret = 0;
1614out:
1615 btrfs_free_path(path);
1616 return ret;
1617}
1618
1619/*
1620 * update file extent items in the tree leaf to point to
1621 * the new locations.
1622 */
1623static noinline_for_stack
1624int replace_file_extents(struct btrfs_trans_handle *trans,
1625 struct reloc_control *rc,
1626 struct btrfs_root *root,
1627 struct extent_buffer *leaf)
1628{
1629 struct btrfs_fs_info *fs_info = root->fs_info;
1630 struct btrfs_key key;
1631 struct btrfs_file_extent_item *fi;
1632 struct inode *inode = NULL;
1633 u64 parent;
1634 u64 bytenr;
1635 u64 new_bytenr = 0;
1636 u64 num_bytes;
1637 u64 end;
1638 u32 nritems;
1639 u32 i;
1640 int ret = 0;
1641 int first = 1;
1642 int dirty = 0;
1643
1644 if (rc->stage != UPDATE_DATA_PTRS)
1645 return 0;
1646
1647 /* reloc trees always use full backref */
1648 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1649 parent = leaf->start;
1650 else
1651 parent = 0;
1652
1653 nritems = btrfs_header_nritems(leaf);
1654 for (i = 0; i < nritems; i++) {
1655 struct btrfs_ref ref = { 0 };
1656
1657 cond_resched();
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
1660 continue;
1661 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1662 if (btrfs_file_extent_type(leaf, fi) ==
1663 BTRFS_FILE_EXTENT_INLINE)
1664 continue;
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1667 if (bytenr == 0)
1668 continue;
1669 if (!in_block_group(bytenr, rc->block_group))
1670 continue;
1671
1672 /*
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1675 */
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1677 if (first) {
1678 inode = find_next_inode(root, key.objectid);
1679 first = 0;
1680 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1681 btrfs_add_delayed_iput(inode);
1682 inode = find_next_inode(root, key.objectid);
1683 }
1684 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1685 end = key.offset +
1686 btrfs_file_extent_num_bytes(leaf, fi);
1687 WARN_ON(!IS_ALIGNED(key.offset,
1688 fs_info->sectorsize));
1689 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1690 end--;
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1692 key.offset, end);
1693 if (!ret)
1694 continue;
1695
1696 btrfs_drop_extent_cache(BTRFS_I(inode),
1697 key.offset, end, 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1699 key.offset, end);
1700 }
1701 }
1702
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1704 bytenr, num_bytes);
1705 if (ret) {
1706 /*
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1709 */
1710 break;
1711 }
1712
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1714 dirty = 1;
1715
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1718 num_bytes, parent);
1719 ref.real_root = root->root_key.objectid;
1720 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1721 key.objectid, key.offset);
1722 ret = btrfs_inc_extent_ref(trans, &ref);
1723 if (ret) {
1724 btrfs_abort_transaction(trans, ret);
1725 break;
1726 }
1727
1728 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1729 num_bytes, parent);
1730 ref.real_root = root->root_key.objectid;
1731 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1732 key.objectid, key.offset);
1733 ret = btrfs_free_extent(trans, &ref);
1734 if (ret) {
1735 btrfs_abort_transaction(trans, ret);
1736 break;
1737 }
1738 }
1739 if (dirty)
1740 btrfs_mark_buffer_dirty(leaf);
1741 if (inode)
1742 btrfs_add_delayed_iput(inode);
1743 return ret;
1744}
1745
1746static noinline_for_stack
1747int memcmp_node_keys(struct extent_buffer *eb, int slot,
1748 struct btrfs_path *path, int level)
1749{
1750 struct btrfs_disk_key key1;
1751 struct btrfs_disk_key key2;
1752 btrfs_node_key(eb, &key1, slot);
1753 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1754 return memcmp(&key1, &key2, sizeof(key1));
1755}
1756
1757/*
1758 * try to replace tree blocks in fs tree with the new blocks
1759 * in reloc tree. tree blocks haven't been modified since the
1760 * reloc tree was create can be replaced.
1761 *
1762 * if a block was replaced, level of the block + 1 is returned.
1763 * if no block got replaced, 0 is returned. if there are other
1764 * errors, a negative error number is returned.
1765 */
1766static noinline_for_stack
1767int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1768 struct btrfs_root *dest, struct btrfs_root *src,
1769 struct btrfs_path *path, struct btrfs_key *next_key,
1770 int lowest_level, int max_level)
1771{
1772 struct btrfs_fs_info *fs_info = dest->fs_info;
1773 struct extent_buffer *eb;
1774 struct extent_buffer *parent;
1775 struct btrfs_ref ref = { 0 };
1776 struct btrfs_key key;
1777 u64 old_bytenr;
1778 u64 new_bytenr;
1779 u64 old_ptr_gen;
1780 u64 new_ptr_gen;
1781 u64 last_snapshot;
1782 u32 blocksize;
1783 int cow = 0;
1784 int level;
1785 int ret;
1786 int slot;
1787
1788 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1789 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1790
1791 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1792again:
1793 slot = path->slots[lowest_level];
1794 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1795
1796 eb = btrfs_lock_root_node(dest);
1797 btrfs_set_lock_blocking_write(eb);
1798 level = btrfs_header_level(eb);
1799
1800 if (level < lowest_level) {
1801 btrfs_tree_unlock(eb);
1802 free_extent_buffer(eb);
1803 return 0;
1804 }
1805
1806 if (cow) {
1807 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1808 BUG_ON(ret);
1809 }
1810 btrfs_set_lock_blocking_write(eb);
1811
1812 if (next_key) {
1813 next_key->objectid = (u64)-1;
1814 next_key->type = (u8)-1;
1815 next_key->offset = (u64)-1;
1816 }
1817
1818 parent = eb;
1819 while (1) {
1820 struct btrfs_key first_key;
1821
1822 level = btrfs_header_level(parent);
1823 BUG_ON(level < lowest_level);
1824
1825 ret = btrfs_bin_search(parent, &key, level, &slot);
1826 if (ret < 0)
1827 break;
1828 if (ret && slot > 0)
1829 slot--;
1830
1831 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1832 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1833
1834 old_bytenr = btrfs_node_blockptr(parent, slot);
1835 blocksize = fs_info->nodesize;
1836 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1837 btrfs_node_key_to_cpu(parent, &first_key, slot);
1838
1839 if (level <= max_level) {
1840 eb = path->nodes[level];
1841 new_bytenr = btrfs_node_blockptr(eb,
1842 path->slots[level]);
1843 new_ptr_gen = btrfs_node_ptr_generation(eb,
1844 path->slots[level]);
1845 } else {
1846 new_bytenr = 0;
1847 new_ptr_gen = 0;
1848 }
1849
1850 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1851 ret = level;
1852 break;
1853 }
1854
1855 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1856 memcmp_node_keys(parent, slot, path, level)) {
1857 if (level <= lowest_level) {
1858 ret = 0;
1859 break;
1860 }
1861
1862 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1863 level - 1, &first_key);
1864 if (IS_ERR(eb)) {
1865 ret = PTR_ERR(eb);
1866 break;
1867 } else if (!extent_buffer_uptodate(eb)) {
1868 ret = -EIO;
1869 free_extent_buffer(eb);
1870 break;
1871 }
1872 btrfs_tree_lock(eb);
1873 if (cow) {
1874 ret = btrfs_cow_block(trans, dest, eb, parent,
1875 slot, &eb);
1876 BUG_ON(ret);
1877 }
1878 btrfs_set_lock_blocking_write(eb);
1879
1880 btrfs_tree_unlock(parent);
1881 free_extent_buffer(parent);
1882
1883 parent = eb;
1884 continue;
1885 }
1886
1887 if (!cow) {
1888 btrfs_tree_unlock(parent);
1889 free_extent_buffer(parent);
1890 cow = 1;
1891 goto again;
1892 }
1893
1894 btrfs_node_key_to_cpu(path->nodes[level], &key,
1895 path->slots[level]);
1896 btrfs_release_path(path);
1897
1898 path->lowest_level = level;
1899 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1900 path->lowest_level = 0;
1901 BUG_ON(ret);
1902
1903 /*
1904 * Info qgroup to trace both subtrees.
1905 *
1906 * We must trace both trees.
1907 * 1) Tree reloc subtree
1908 * If not traced, we will leak data numbers
1909 * 2) Fs subtree
1910 * If not traced, we will double count old data
1911 *
1912 * We don't scan the subtree right now, but only record
1913 * the swapped tree blocks.
1914 * The real subtree rescan is delayed until we have new
1915 * CoW on the subtree root node before transaction commit.
1916 */
1917 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1918 rc->block_group, parent, slot,
1919 path->nodes[level], path->slots[level],
1920 last_snapshot);
1921 if (ret < 0)
1922 break;
1923 /*
1924 * swap blocks in fs tree and reloc tree.
1925 */
1926 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1927 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1928 btrfs_mark_buffer_dirty(parent);
1929
1930 btrfs_set_node_blockptr(path->nodes[level],
1931 path->slots[level], old_bytenr);
1932 btrfs_set_node_ptr_generation(path->nodes[level],
1933 path->slots[level], old_ptr_gen);
1934 btrfs_mark_buffer_dirty(path->nodes[level]);
1935
1936 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1937 blocksize, path->nodes[level]->start);
1938 ref.skip_qgroup = true;
1939 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1940 ret = btrfs_inc_extent_ref(trans, &ref);
1941 BUG_ON(ret);
1942 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1943 blocksize, 0);
1944 ref.skip_qgroup = true;
1945 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1946 ret = btrfs_inc_extent_ref(trans, &ref);
1947 BUG_ON(ret);
1948
1949 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1950 blocksize, path->nodes[level]->start);
1951 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1952 ref.skip_qgroup = true;
1953 ret = btrfs_free_extent(trans, &ref);
1954 BUG_ON(ret);
1955
1956 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1957 blocksize, 0);
1958 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1959 ref.skip_qgroup = true;
1960 ret = btrfs_free_extent(trans, &ref);
1961 BUG_ON(ret);
1962
1963 btrfs_unlock_up_safe(path, 0);
1964
1965 ret = level;
1966 break;
1967 }
1968 btrfs_tree_unlock(parent);
1969 free_extent_buffer(parent);
1970 return ret;
1971}
1972
1973/*
1974 * helper to find next relocated block in reloc tree
1975 */
1976static noinline_for_stack
1977int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1978 int *level)
1979{
1980 struct extent_buffer *eb;
1981 int i;
1982 u64 last_snapshot;
1983 u32 nritems;
1984
1985 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1986
1987 for (i = 0; i < *level; i++) {
1988 free_extent_buffer(path->nodes[i]);
1989 path->nodes[i] = NULL;
1990 }
1991
1992 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1993 eb = path->nodes[i];
1994 nritems = btrfs_header_nritems(eb);
1995 while (path->slots[i] + 1 < nritems) {
1996 path->slots[i]++;
1997 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1998 last_snapshot)
1999 continue;
2000
2001 *level = i;
2002 return 0;
2003 }
2004 free_extent_buffer(path->nodes[i]);
2005 path->nodes[i] = NULL;
2006 }
2007 return 1;
2008}
2009
2010/*
2011 * walk down reloc tree to find relocated block of lowest level
2012 */
2013static noinline_for_stack
2014int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2015 int *level)
2016{
2017 struct btrfs_fs_info *fs_info = root->fs_info;
2018 struct extent_buffer *eb = NULL;
2019 int i;
2020 u64 bytenr;
2021 u64 ptr_gen = 0;
2022 u64 last_snapshot;
2023 u32 nritems;
2024
2025 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2026
2027 for (i = *level; i > 0; i--) {
2028 struct btrfs_key first_key;
2029
2030 eb = path->nodes[i];
2031 nritems = btrfs_header_nritems(eb);
2032 while (path->slots[i] < nritems) {
2033 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2034 if (ptr_gen > last_snapshot)
2035 break;
2036 path->slots[i]++;
2037 }
2038 if (path->slots[i] >= nritems) {
2039 if (i == *level)
2040 break;
2041 *level = i + 1;
2042 return 0;
2043 }
2044 if (i == 1) {
2045 *level = i;
2046 return 0;
2047 }
2048
2049 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2050 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2051 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2052 &first_key);
2053 if (IS_ERR(eb)) {
2054 return PTR_ERR(eb);
2055 } else if (!extent_buffer_uptodate(eb)) {
2056 free_extent_buffer(eb);
2057 return -EIO;
2058 }
2059 BUG_ON(btrfs_header_level(eb) != i - 1);
2060 path->nodes[i - 1] = eb;
2061 path->slots[i - 1] = 0;
2062 }
2063 return 1;
2064}
2065
2066/*
2067 * invalidate extent cache for file extents whose key in range of
2068 * [min_key, max_key)
2069 */
2070static int invalidate_extent_cache(struct btrfs_root *root,
2071 struct btrfs_key *min_key,
2072 struct btrfs_key *max_key)
2073{
2074 struct btrfs_fs_info *fs_info = root->fs_info;
2075 struct inode *inode = NULL;
2076 u64 objectid;
2077 u64 start, end;
2078 u64 ino;
2079
2080 objectid = min_key->objectid;
2081 while (1) {
2082 cond_resched();
2083 iput(inode);
2084
2085 if (objectid > max_key->objectid)
2086 break;
2087
2088 inode = find_next_inode(root, objectid);
2089 if (!inode)
2090 break;
2091 ino = btrfs_ino(BTRFS_I(inode));
2092
2093 if (ino > max_key->objectid) {
2094 iput(inode);
2095 break;
2096 }
2097
2098 objectid = ino + 1;
2099 if (!S_ISREG(inode->i_mode))
2100 continue;
2101
2102 if (unlikely(min_key->objectid == ino)) {
2103 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2104 continue;
2105 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2106 start = 0;
2107 else {
2108 start = min_key->offset;
2109 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2110 }
2111 } else {
2112 start = 0;
2113 }
2114
2115 if (unlikely(max_key->objectid == ino)) {
2116 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2117 continue;
2118 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2119 end = (u64)-1;
2120 } else {
2121 if (max_key->offset == 0)
2122 continue;
2123 end = max_key->offset;
2124 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2125 end--;
2126 }
2127 } else {
2128 end = (u64)-1;
2129 }
2130
2131 /* the lock_extent waits for readpage to complete */
2132 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2133 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2134 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2135 }
2136 return 0;
2137}
2138
2139static int find_next_key(struct btrfs_path *path, int level,
2140 struct btrfs_key *key)
2141
2142{
2143 while (level < BTRFS_MAX_LEVEL) {
2144 if (!path->nodes[level])
2145 break;
2146 if (path->slots[level] + 1 <
2147 btrfs_header_nritems(path->nodes[level])) {
2148 btrfs_node_key_to_cpu(path->nodes[level], key,
2149 path->slots[level] + 1);
2150 return 0;
2151 }
2152 level++;
2153 }
2154 return 1;
2155}
2156
2157/*
2158 * Insert current subvolume into reloc_control::dirty_subvol_roots
2159 */
2160static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2161 struct reloc_control *rc,
2162 struct btrfs_root *root)
2163{
2164 struct btrfs_root *reloc_root = root->reloc_root;
2165 struct btrfs_root_item *reloc_root_item;
2166
2167 /* @root must be a subvolume tree root with a valid reloc tree */
2168 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2169 ASSERT(reloc_root);
2170
2171 reloc_root_item = &reloc_root->root_item;
2172 memset(&reloc_root_item->drop_progress, 0,
2173 sizeof(reloc_root_item->drop_progress));
2174 reloc_root_item->drop_level = 0;
2175 btrfs_set_root_refs(reloc_root_item, 0);
2176 btrfs_update_reloc_root(trans, root);
2177
2178 if (list_empty(&root->reloc_dirty_list)) {
2179 btrfs_grab_fs_root(root);
2180 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2181 }
2182}
2183
2184static int clean_dirty_subvols(struct reloc_control *rc)
2185{
2186 struct btrfs_root *root;
2187 struct btrfs_root *next;
2188 int ret = 0;
2189 int ret2;
2190
2191 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2192 reloc_dirty_list) {
2193 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2194 /* Merged subvolume, cleanup its reloc root */
2195 struct btrfs_root *reloc_root = root->reloc_root;
2196
2197 list_del_init(&root->reloc_dirty_list);
2198 root->reloc_root = NULL;
2199 if (reloc_root) {
2200
2201 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2202 if (ret2 < 0 && !ret)
2203 ret = ret2;
2204 }
2205 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2206 btrfs_put_fs_root(root);
2207 } else {
2208 /* Orphan reloc tree, just clean it up */
2209 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2210 if (ret2 < 0 && !ret)
2211 ret = ret2;
2212 }
2213 }
2214 return ret;
2215}
2216
2217/*
2218 * merge the relocated tree blocks in reloc tree with corresponding
2219 * fs tree.
2220 */
2221static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2222 struct btrfs_root *root)
2223{
2224 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2225 struct btrfs_key key;
2226 struct btrfs_key next_key;
2227 struct btrfs_trans_handle *trans = NULL;
2228 struct btrfs_root *reloc_root;
2229 struct btrfs_root_item *root_item;
2230 struct btrfs_path *path;
2231 struct extent_buffer *leaf;
2232 int level;
2233 int max_level;
2234 int replaced = 0;
2235 int ret;
2236 int err = 0;
2237 u32 min_reserved;
2238
2239 path = btrfs_alloc_path();
2240 if (!path)
2241 return -ENOMEM;
2242 path->reada = READA_FORWARD;
2243
2244 reloc_root = root->reloc_root;
2245 root_item = &reloc_root->root_item;
2246
2247 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2248 level = btrfs_root_level(root_item);
2249 extent_buffer_get(reloc_root->node);
2250 path->nodes[level] = reloc_root->node;
2251 path->slots[level] = 0;
2252 } else {
2253 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2254
2255 level = root_item->drop_level;
2256 BUG_ON(level == 0);
2257 path->lowest_level = level;
2258 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2259 path->lowest_level = 0;
2260 if (ret < 0) {
2261 btrfs_free_path(path);
2262 return ret;
2263 }
2264
2265 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2266 path->slots[level]);
2267 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2268
2269 btrfs_unlock_up_safe(path, 0);
2270 }
2271
2272 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2273 memset(&next_key, 0, sizeof(next_key));
2274
2275 while (1) {
2276 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2277 BTRFS_RESERVE_FLUSH_ALL);
2278 if (ret) {
2279 err = ret;
2280 goto out;
2281 }
2282 trans = btrfs_start_transaction(root, 0);
2283 if (IS_ERR(trans)) {
2284 err = PTR_ERR(trans);
2285 trans = NULL;
2286 goto out;
2287 }
2288 trans->block_rsv = rc->block_rsv;
2289
2290 replaced = 0;
2291 max_level = level;
2292
2293 ret = walk_down_reloc_tree(reloc_root, path, &level);
2294 if (ret < 0) {
2295 err = ret;
2296 goto out;
2297 }
2298 if (ret > 0)
2299 break;
2300
2301 if (!find_next_key(path, level, &key) &&
2302 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2303 ret = 0;
2304 } else {
2305 ret = replace_path(trans, rc, root, reloc_root, path,
2306 &next_key, level, max_level);
2307 }
2308 if (ret < 0) {
2309 err = ret;
2310 goto out;
2311 }
2312
2313 if (ret > 0) {
2314 level = ret;
2315 btrfs_node_key_to_cpu(path->nodes[level], &key,
2316 path->slots[level]);
2317 replaced = 1;
2318 }
2319
2320 ret = walk_up_reloc_tree(reloc_root, path, &level);
2321 if (ret > 0)
2322 break;
2323
2324 BUG_ON(level == 0);
2325 /*
2326 * save the merging progress in the drop_progress.
2327 * this is OK since root refs == 1 in this case.
2328 */
2329 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2330 path->slots[level]);
2331 root_item->drop_level = level;
2332
2333 btrfs_end_transaction_throttle(trans);
2334 trans = NULL;
2335
2336 btrfs_btree_balance_dirty(fs_info);
2337
2338 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2339 invalidate_extent_cache(root, &key, &next_key);
2340 }
2341
2342 /*
2343 * handle the case only one block in the fs tree need to be
2344 * relocated and the block is tree root.
2345 */
2346 leaf = btrfs_lock_root_node(root);
2347 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2348 btrfs_tree_unlock(leaf);
2349 free_extent_buffer(leaf);
2350 if (ret < 0)
2351 err = ret;
2352out:
2353 btrfs_free_path(path);
2354
2355 if (err == 0)
2356 insert_dirty_subvol(trans, rc, root);
2357
2358 if (trans)
2359 btrfs_end_transaction_throttle(trans);
2360
2361 btrfs_btree_balance_dirty(fs_info);
2362
2363 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2364 invalidate_extent_cache(root, &key, &next_key);
2365
2366 return err;
2367}
2368
2369static noinline_for_stack
2370int prepare_to_merge(struct reloc_control *rc, int err)
2371{
2372 struct btrfs_root *root = rc->extent_root;
2373 struct btrfs_fs_info *fs_info = root->fs_info;
2374 struct btrfs_root *reloc_root;
2375 struct btrfs_trans_handle *trans;
2376 LIST_HEAD(reloc_roots);
2377 u64 num_bytes = 0;
2378 int ret;
2379
2380 mutex_lock(&fs_info->reloc_mutex);
2381 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2382 rc->merging_rsv_size += rc->nodes_relocated * 2;
2383 mutex_unlock(&fs_info->reloc_mutex);
2384
2385again:
2386 if (!err) {
2387 num_bytes = rc->merging_rsv_size;
2388 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2389 BTRFS_RESERVE_FLUSH_ALL);
2390 if (ret)
2391 err = ret;
2392 }
2393
2394 trans = btrfs_join_transaction(rc->extent_root);
2395 if (IS_ERR(trans)) {
2396 if (!err)
2397 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2398 num_bytes);
2399 return PTR_ERR(trans);
2400 }
2401
2402 if (!err) {
2403 if (num_bytes != rc->merging_rsv_size) {
2404 btrfs_end_transaction(trans);
2405 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2406 num_bytes);
2407 goto again;
2408 }
2409 }
2410
2411 rc->merge_reloc_tree = 1;
2412
2413 while (!list_empty(&rc->reloc_roots)) {
2414 reloc_root = list_entry(rc->reloc_roots.next,
2415 struct btrfs_root, root_list);
2416 list_del_init(&reloc_root->root_list);
2417
2418 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2419 BUG_ON(IS_ERR(root));
2420 BUG_ON(root->reloc_root != reloc_root);
2421
2422 /*
2423 * set reference count to 1, so btrfs_recover_relocation
2424 * knows it should resumes merging
2425 */
2426 if (!err)
2427 btrfs_set_root_refs(&reloc_root->root_item, 1);
2428 btrfs_update_reloc_root(trans, root);
2429
2430 list_add(&reloc_root->root_list, &reloc_roots);
2431 }
2432
2433 list_splice(&reloc_roots, &rc->reloc_roots);
2434
2435 if (!err)
2436 btrfs_commit_transaction(trans);
2437 else
2438 btrfs_end_transaction(trans);
2439 return err;
2440}
2441
2442static noinline_for_stack
2443void free_reloc_roots(struct list_head *list)
2444{
2445 struct btrfs_root *reloc_root;
2446
2447 while (!list_empty(list)) {
2448 reloc_root = list_entry(list->next, struct btrfs_root,
2449 root_list);
2450 __del_reloc_root(reloc_root);
2451 free_extent_buffer(reloc_root->node);
2452 free_extent_buffer(reloc_root->commit_root);
2453 reloc_root->node = NULL;
2454 reloc_root->commit_root = NULL;
2455 }
2456}
2457
2458static noinline_for_stack
2459void merge_reloc_roots(struct reloc_control *rc)
2460{
2461 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2462 struct btrfs_root *root;
2463 struct btrfs_root *reloc_root;
2464 LIST_HEAD(reloc_roots);
2465 int found = 0;
2466 int ret = 0;
2467again:
2468 root = rc->extent_root;
2469
2470 /*
2471 * this serializes us with btrfs_record_root_in_transaction,
2472 * we have to make sure nobody is in the middle of
2473 * adding their roots to the list while we are
2474 * doing this splice
2475 */
2476 mutex_lock(&fs_info->reloc_mutex);
2477 list_splice_init(&rc->reloc_roots, &reloc_roots);
2478 mutex_unlock(&fs_info->reloc_mutex);
2479
2480 while (!list_empty(&reloc_roots)) {
2481 found = 1;
2482 reloc_root = list_entry(reloc_roots.next,
2483 struct btrfs_root, root_list);
2484
2485 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2486 root = read_fs_root(fs_info,
2487 reloc_root->root_key.offset);
2488 BUG_ON(IS_ERR(root));
2489 BUG_ON(root->reloc_root != reloc_root);
2490
2491 ret = merge_reloc_root(rc, root);
2492 if (ret) {
2493 if (list_empty(&reloc_root->root_list))
2494 list_add_tail(&reloc_root->root_list,
2495 &reloc_roots);
2496 goto out;
2497 }
2498 } else {
2499 list_del_init(&reloc_root->root_list);
2500 /* Don't forget to queue this reloc root for cleanup */
2501 list_add_tail(&reloc_root->reloc_dirty_list,
2502 &rc->dirty_subvol_roots);
2503 }
2504 }
2505
2506 if (found) {
2507 found = 0;
2508 goto again;
2509 }
2510out:
2511 if (ret) {
2512 btrfs_handle_fs_error(fs_info, ret, NULL);
2513 if (!list_empty(&reloc_roots))
2514 free_reloc_roots(&reloc_roots);
2515
2516 /* new reloc root may be added */
2517 mutex_lock(&fs_info->reloc_mutex);
2518 list_splice_init(&rc->reloc_roots, &reloc_roots);
2519 mutex_unlock(&fs_info->reloc_mutex);
2520 if (!list_empty(&reloc_roots))
2521 free_reloc_roots(&reloc_roots);
2522 }
2523
2524 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2525}
2526
2527static void free_block_list(struct rb_root *blocks)
2528{
2529 struct tree_block *block;
2530 struct rb_node *rb_node;
2531 while ((rb_node = rb_first(blocks))) {
2532 block = rb_entry(rb_node, struct tree_block, rb_node);
2533 rb_erase(rb_node, blocks);
2534 kfree(block);
2535 }
2536}
2537
2538static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2539 struct btrfs_root *reloc_root)
2540{
2541 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2542 struct btrfs_root *root;
2543
2544 if (reloc_root->last_trans == trans->transid)
2545 return 0;
2546
2547 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2548 BUG_ON(IS_ERR(root));
2549 BUG_ON(root->reloc_root != reloc_root);
2550
2551 return btrfs_record_root_in_trans(trans, root);
2552}
2553
2554static noinline_for_stack
2555struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2556 struct reloc_control *rc,
2557 struct backref_node *node,
2558 struct backref_edge *edges[])
2559{
2560 struct backref_node *next;
2561 struct btrfs_root *root;
2562 int index = 0;
2563
2564 next = node;
2565 while (1) {
2566 cond_resched();
2567 next = walk_up_backref(next, edges, &index);
2568 root = next->root;
2569 BUG_ON(!root);
2570 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2571
2572 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2573 record_reloc_root_in_trans(trans, root);
2574 break;
2575 }
2576
2577 btrfs_record_root_in_trans(trans, root);
2578 root = root->reloc_root;
2579
2580 if (next->new_bytenr != root->node->start) {
2581 BUG_ON(next->new_bytenr);
2582 BUG_ON(!list_empty(&next->list));
2583 next->new_bytenr = root->node->start;
2584 next->root = root;
2585 list_add_tail(&next->list,
2586 &rc->backref_cache.changed);
2587 __mark_block_processed(rc, next);
2588 break;
2589 }
2590
2591 WARN_ON(1);
2592 root = NULL;
2593 next = walk_down_backref(edges, &index);
2594 if (!next || next->level <= node->level)
2595 break;
2596 }
2597 if (!root)
2598 return NULL;
2599
2600 next = node;
2601 /* setup backref node path for btrfs_reloc_cow_block */
2602 while (1) {
2603 rc->backref_cache.path[next->level] = next;
2604 if (--index < 0)
2605 break;
2606 next = edges[index]->node[UPPER];
2607 }
2608 return root;
2609}
2610
2611/*
2612 * select a tree root for relocation. return NULL if the block
2613 * is reference counted. we should use do_relocation() in this
2614 * case. return a tree root pointer if the block isn't reference
2615 * counted. return -ENOENT if the block is root of reloc tree.
2616 */
2617static noinline_for_stack
2618struct btrfs_root *select_one_root(struct backref_node *node)
2619{
2620 struct backref_node *next;
2621 struct btrfs_root *root;
2622 struct btrfs_root *fs_root = NULL;
2623 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2624 int index = 0;
2625
2626 next = node;
2627 while (1) {
2628 cond_resched();
2629 next = walk_up_backref(next, edges, &index);
2630 root = next->root;
2631 BUG_ON(!root);
2632
2633 /* no other choice for non-references counted tree */
2634 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2635 return root;
2636
2637 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2638 fs_root = root;
2639
2640 if (next != node)
2641 return NULL;
2642
2643 next = walk_down_backref(edges, &index);
2644 if (!next || next->level <= node->level)
2645 break;
2646 }
2647
2648 if (!fs_root)
2649 return ERR_PTR(-ENOENT);
2650 return fs_root;
2651}
2652
2653static noinline_for_stack
2654u64 calcu_metadata_size(struct reloc_control *rc,
2655 struct backref_node *node, int reserve)
2656{
2657 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2658 struct backref_node *next = node;
2659 struct backref_edge *edge;
2660 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2661 u64 num_bytes = 0;
2662 int index = 0;
2663
2664 BUG_ON(reserve && node->processed);
2665
2666 while (next) {
2667 cond_resched();
2668 while (1) {
2669 if (next->processed && (reserve || next != node))
2670 break;
2671
2672 num_bytes += fs_info->nodesize;
2673
2674 if (list_empty(&next->upper))
2675 break;
2676
2677 edge = list_entry(next->upper.next,
2678 struct backref_edge, list[LOWER]);
2679 edges[index++] = edge;
2680 next = edge->node[UPPER];
2681 }
2682 next = walk_down_backref(edges, &index);
2683 }
2684 return num_bytes;
2685}
2686
2687static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2688 struct reloc_control *rc,
2689 struct backref_node *node)
2690{
2691 struct btrfs_root *root = rc->extent_root;
2692 struct btrfs_fs_info *fs_info = root->fs_info;
2693 u64 num_bytes;
2694 int ret;
2695 u64 tmp;
2696
2697 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2698
2699 trans->block_rsv = rc->block_rsv;
2700 rc->reserved_bytes += num_bytes;
2701
2702 /*
2703 * We are under a transaction here so we can only do limited flushing.
2704 * If we get an enospc just kick back -EAGAIN so we know to drop the
2705 * transaction and try to refill when we can flush all the things.
2706 */
2707 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2708 BTRFS_RESERVE_FLUSH_LIMIT);
2709 if (ret) {
2710 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2711 while (tmp <= rc->reserved_bytes)
2712 tmp <<= 1;
2713 /*
2714 * only one thread can access block_rsv at this point,
2715 * so we don't need hold lock to protect block_rsv.
2716 * we expand more reservation size here to allow enough
2717 * space for relocation and we will return earlier in
2718 * enospc case.
2719 */
2720 rc->block_rsv->size = tmp + fs_info->nodesize *
2721 RELOCATION_RESERVED_NODES;
2722 return -EAGAIN;
2723 }
2724
2725 return 0;
2726}
2727
2728/*
2729 * relocate a block tree, and then update pointers in upper level
2730 * blocks that reference the block to point to the new location.
2731 *
2732 * if called by link_to_upper, the block has already been relocated.
2733 * in that case this function just updates pointers.
2734 */
2735static int do_relocation(struct btrfs_trans_handle *trans,
2736 struct reloc_control *rc,
2737 struct backref_node *node,
2738 struct btrfs_key *key,
2739 struct btrfs_path *path, int lowest)
2740{
2741 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2742 struct backref_node *upper;
2743 struct backref_edge *edge;
2744 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2745 struct btrfs_root *root;
2746 struct extent_buffer *eb;
2747 u32 blocksize;
2748 u64 bytenr;
2749 u64 generation;
2750 int slot;
2751 int ret;
2752 int err = 0;
2753
2754 BUG_ON(lowest && node->eb);
2755
2756 path->lowest_level = node->level + 1;
2757 rc->backref_cache.path[node->level] = node;
2758 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2759 struct btrfs_key first_key;
2760 struct btrfs_ref ref = { 0 };
2761
2762 cond_resched();
2763
2764 upper = edge->node[UPPER];
2765 root = select_reloc_root(trans, rc, upper, edges);
2766 BUG_ON(!root);
2767
2768 if (upper->eb && !upper->locked) {
2769 if (!lowest) {
2770 ret = btrfs_bin_search(upper->eb, key,
2771 upper->level, &slot);
2772 if (ret < 0) {
2773 err = ret;
2774 goto next;
2775 }
2776 BUG_ON(ret);
2777 bytenr = btrfs_node_blockptr(upper->eb, slot);
2778 if (node->eb->start == bytenr)
2779 goto next;
2780 }
2781 drop_node_buffer(upper);
2782 }
2783
2784 if (!upper->eb) {
2785 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2786 if (ret) {
2787 if (ret < 0)
2788 err = ret;
2789 else
2790 err = -ENOENT;
2791
2792 btrfs_release_path(path);
2793 break;
2794 }
2795
2796 if (!upper->eb) {
2797 upper->eb = path->nodes[upper->level];
2798 path->nodes[upper->level] = NULL;
2799 } else {
2800 BUG_ON(upper->eb != path->nodes[upper->level]);
2801 }
2802
2803 upper->locked = 1;
2804 path->locks[upper->level] = 0;
2805
2806 slot = path->slots[upper->level];
2807 btrfs_release_path(path);
2808 } else {
2809 ret = btrfs_bin_search(upper->eb, key, upper->level,
2810 &slot);
2811 if (ret < 0) {
2812 err = ret;
2813 goto next;
2814 }
2815 BUG_ON(ret);
2816 }
2817
2818 bytenr = btrfs_node_blockptr(upper->eb, slot);
2819 if (lowest) {
2820 if (bytenr != node->bytenr) {
2821 btrfs_err(root->fs_info,
2822 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2823 bytenr, node->bytenr, slot,
2824 upper->eb->start);
2825 err = -EIO;
2826 goto next;
2827 }
2828 } else {
2829 if (node->eb->start == bytenr)
2830 goto next;
2831 }
2832
2833 blocksize = root->fs_info->nodesize;
2834 generation = btrfs_node_ptr_generation(upper->eb, slot);
2835 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2836 eb = read_tree_block(fs_info, bytenr, generation,
2837 upper->level - 1, &first_key);
2838 if (IS_ERR(eb)) {
2839 err = PTR_ERR(eb);
2840 goto next;
2841 } else if (!extent_buffer_uptodate(eb)) {
2842 free_extent_buffer(eb);
2843 err = -EIO;
2844 goto next;
2845 }
2846 btrfs_tree_lock(eb);
2847 btrfs_set_lock_blocking_write(eb);
2848
2849 if (!node->eb) {
2850 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2851 slot, &eb);
2852 btrfs_tree_unlock(eb);
2853 free_extent_buffer(eb);
2854 if (ret < 0) {
2855 err = ret;
2856 goto next;
2857 }
2858 BUG_ON(node->eb != eb);
2859 } else {
2860 btrfs_set_node_blockptr(upper->eb, slot,
2861 node->eb->start);
2862 btrfs_set_node_ptr_generation(upper->eb, slot,
2863 trans->transid);
2864 btrfs_mark_buffer_dirty(upper->eb);
2865
2866 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2867 node->eb->start, blocksize,
2868 upper->eb->start);
2869 ref.real_root = root->root_key.objectid;
2870 btrfs_init_tree_ref(&ref, node->level,
2871 btrfs_header_owner(upper->eb));
2872 ret = btrfs_inc_extent_ref(trans, &ref);
2873 BUG_ON(ret);
2874
2875 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2876 BUG_ON(ret);
2877 }
2878next:
2879 if (!upper->pending)
2880 drop_node_buffer(upper);
2881 else
2882 unlock_node_buffer(upper);
2883 if (err)
2884 break;
2885 }
2886
2887 if (!err && node->pending) {
2888 drop_node_buffer(node);
2889 list_move_tail(&node->list, &rc->backref_cache.changed);
2890 node->pending = 0;
2891 }
2892
2893 path->lowest_level = 0;
2894 BUG_ON(err == -ENOSPC);
2895 return err;
2896}
2897
2898static int link_to_upper(struct btrfs_trans_handle *trans,
2899 struct reloc_control *rc,
2900 struct backref_node *node,
2901 struct btrfs_path *path)
2902{
2903 struct btrfs_key key;
2904
2905 btrfs_node_key_to_cpu(node->eb, &key, 0);
2906 return do_relocation(trans, rc, node, &key, path, 0);
2907}
2908
2909static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2910 struct reloc_control *rc,
2911 struct btrfs_path *path, int err)
2912{
2913 LIST_HEAD(list);
2914 struct backref_cache *cache = &rc->backref_cache;
2915 struct backref_node *node;
2916 int level;
2917 int ret;
2918
2919 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2920 while (!list_empty(&cache->pending[level])) {
2921 node = list_entry(cache->pending[level].next,
2922 struct backref_node, list);
2923 list_move_tail(&node->list, &list);
2924 BUG_ON(!node->pending);
2925
2926 if (!err) {
2927 ret = link_to_upper(trans, rc, node, path);
2928 if (ret < 0)
2929 err = ret;
2930 }
2931 }
2932 list_splice_init(&list, &cache->pending[level]);
2933 }
2934 return err;
2935}
2936
2937static void mark_block_processed(struct reloc_control *rc,
2938 u64 bytenr, u32 blocksize)
2939{
2940 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2941 EXTENT_DIRTY);
2942}
2943
2944static void __mark_block_processed(struct reloc_control *rc,
2945 struct backref_node *node)
2946{
2947 u32 blocksize;
2948 if (node->level == 0 ||
2949 in_block_group(node->bytenr, rc->block_group)) {
2950 blocksize = rc->extent_root->fs_info->nodesize;
2951 mark_block_processed(rc, node->bytenr, blocksize);
2952 }
2953 node->processed = 1;
2954}
2955
2956/*
2957 * mark a block and all blocks directly/indirectly reference the block
2958 * as processed.
2959 */
2960static void update_processed_blocks(struct reloc_control *rc,
2961 struct backref_node *node)
2962{
2963 struct backref_node *next = node;
2964 struct backref_edge *edge;
2965 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2966 int index = 0;
2967
2968 while (next) {
2969 cond_resched();
2970 while (1) {
2971 if (next->processed)
2972 break;
2973
2974 __mark_block_processed(rc, next);
2975
2976 if (list_empty(&next->upper))
2977 break;
2978
2979 edge = list_entry(next->upper.next,
2980 struct backref_edge, list[LOWER]);
2981 edges[index++] = edge;
2982 next = edge->node[UPPER];
2983 }
2984 next = walk_down_backref(edges, &index);
2985 }
2986}
2987
2988static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2989{
2990 u32 blocksize = rc->extent_root->fs_info->nodesize;
2991
2992 if (test_range_bit(&rc->processed_blocks, bytenr,
2993 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2994 return 1;
2995 return 0;
2996}
2997
2998static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2999 struct tree_block *block)
3000{
3001 struct extent_buffer *eb;
3002
3003 BUG_ON(block->key_ready);
3004 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
3005 block->level, NULL);
3006 if (IS_ERR(eb)) {
3007 return PTR_ERR(eb);
3008 } else if (!extent_buffer_uptodate(eb)) {
3009 free_extent_buffer(eb);
3010 return -EIO;
3011 }
3012 if (block->level == 0)
3013 btrfs_item_key_to_cpu(eb, &block->key, 0);
3014 else
3015 btrfs_node_key_to_cpu(eb, &block->key, 0);
3016 free_extent_buffer(eb);
3017 block->key_ready = 1;
3018 return 0;
3019}
3020
3021/*
3022 * helper function to relocate a tree block
3023 */
3024static int relocate_tree_block(struct btrfs_trans_handle *trans,
3025 struct reloc_control *rc,
3026 struct backref_node *node,
3027 struct btrfs_key *key,
3028 struct btrfs_path *path)
3029{
3030 struct btrfs_root *root;
3031 int ret = 0;
3032
3033 if (!node)
3034 return 0;
3035
3036 BUG_ON(node->processed);
3037 root = select_one_root(node);
3038 if (root == ERR_PTR(-ENOENT)) {
3039 update_processed_blocks(rc, node);
3040 goto out;
3041 }
3042
3043 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3044 ret = reserve_metadata_space(trans, rc, node);
3045 if (ret)
3046 goto out;
3047 }
3048
3049 if (root) {
3050 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3051 BUG_ON(node->new_bytenr);
3052 BUG_ON(!list_empty(&node->list));
3053 btrfs_record_root_in_trans(trans, root);
3054 root = root->reloc_root;
3055 node->new_bytenr = root->node->start;
3056 node->root = root;
3057 list_add_tail(&node->list, &rc->backref_cache.changed);
3058 } else {
3059 path->lowest_level = node->level;
3060 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3061 btrfs_release_path(path);
3062 if (ret > 0)
3063 ret = 0;
3064 }
3065 if (!ret)
3066 update_processed_blocks(rc, node);
3067 } else {
3068 ret = do_relocation(trans, rc, node, key, path, 1);
3069 }
3070out:
3071 if (ret || node->level == 0 || node->cowonly)
3072 remove_backref_node(&rc->backref_cache, node);
3073 return ret;
3074}
3075
3076/*
3077 * relocate a list of blocks
3078 */
3079static noinline_for_stack
3080int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3081 struct reloc_control *rc, struct rb_root *blocks)
3082{
3083 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3084 struct backref_node *node;
3085 struct btrfs_path *path;
3086 struct tree_block *block;
3087 struct tree_block *next;
3088 int ret;
3089 int err = 0;
3090
3091 path = btrfs_alloc_path();
3092 if (!path) {
3093 err = -ENOMEM;
3094 goto out_free_blocks;
3095 }
3096
3097 /* Kick in readahead for tree blocks with missing keys */
3098 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3099 if (!block->key_ready)
3100 readahead_tree_block(fs_info, block->bytenr);
3101 }
3102
3103 /* Get first keys */
3104 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3105 if (!block->key_ready) {
3106 err = get_tree_block_key(fs_info, block);
3107 if (err)
3108 goto out_free_path;
3109 }
3110 }
3111
3112 /* Do tree relocation */
3113 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3114 node = build_backref_tree(rc, &block->key,
3115 block->level, block->bytenr);
3116 if (IS_ERR(node)) {
3117 err = PTR_ERR(node);
3118 goto out;
3119 }
3120
3121 ret = relocate_tree_block(trans, rc, node, &block->key,
3122 path);
3123 if (ret < 0) {
3124 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3125 err = ret;
3126 goto out;
3127 }
3128 }
3129out:
3130 err = finish_pending_nodes(trans, rc, path, err);
3131
3132out_free_path:
3133 btrfs_free_path(path);
3134out_free_blocks:
3135 free_block_list(blocks);
3136 return err;
3137}
3138
3139static noinline_for_stack
3140int prealloc_file_extent_cluster(struct inode *inode,
3141 struct file_extent_cluster *cluster)
3142{
3143 u64 alloc_hint = 0;
3144 u64 start;
3145 u64 end;
3146 u64 offset = BTRFS_I(inode)->index_cnt;
3147 u64 num_bytes;
3148 int nr = 0;
3149 int ret = 0;
3150 u64 prealloc_start = cluster->start - offset;
3151 u64 prealloc_end = cluster->end - offset;
3152 u64 cur_offset;
3153 struct extent_changeset *data_reserved = NULL;
3154
3155 BUG_ON(cluster->start != cluster->boundary[0]);
3156 inode_lock(inode);
3157
3158 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3159 prealloc_end + 1 - prealloc_start);
3160 if (ret)
3161 goto out;
3162
3163 cur_offset = prealloc_start;
3164 while (nr < cluster->nr) {
3165 start = cluster->boundary[nr] - offset;
3166 if (nr + 1 < cluster->nr)
3167 end = cluster->boundary[nr + 1] - 1 - offset;
3168 else
3169 end = cluster->end - offset;
3170
3171 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3172 num_bytes = end + 1 - start;
3173 if (cur_offset < start)
3174 btrfs_free_reserved_data_space(inode, data_reserved,
3175 cur_offset, start - cur_offset);
3176 ret = btrfs_prealloc_file_range(inode, 0, start,
3177 num_bytes, num_bytes,
3178 end + 1, &alloc_hint);
3179 cur_offset = end + 1;
3180 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3181 if (ret)
3182 break;
3183 nr++;
3184 }
3185 if (cur_offset < prealloc_end)
3186 btrfs_free_reserved_data_space(inode, data_reserved,
3187 cur_offset, prealloc_end + 1 - cur_offset);
3188out:
3189 inode_unlock(inode);
3190 extent_changeset_free(data_reserved);
3191 return ret;
3192}
3193
3194static noinline_for_stack
3195int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3196 u64 block_start)
3197{
3198 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3199 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3200 struct extent_map *em;
3201 int ret = 0;
3202
3203 em = alloc_extent_map();
3204 if (!em)
3205 return -ENOMEM;
3206
3207 em->start = start;
3208 em->len = end + 1 - start;
3209 em->block_len = em->len;
3210 em->block_start = block_start;
3211 em->bdev = fs_info->fs_devices->latest_bdev;
3212 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3213
3214 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3215 while (1) {
3216 write_lock(&em_tree->lock);
3217 ret = add_extent_mapping(em_tree, em, 0);
3218 write_unlock(&em_tree->lock);
3219 if (ret != -EEXIST) {
3220 free_extent_map(em);
3221 break;
3222 }
3223 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3224 }
3225 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3226 return ret;
3227}
3228
3229static int relocate_file_extent_cluster(struct inode *inode,
3230 struct file_extent_cluster *cluster)
3231{
3232 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3233 u64 page_start;
3234 u64 page_end;
3235 u64 offset = BTRFS_I(inode)->index_cnt;
3236 unsigned long index;
3237 unsigned long last_index;
3238 struct page *page;
3239 struct file_ra_state *ra;
3240 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3241 int nr = 0;
3242 int ret = 0;
3243
3244 if (!cluster->nr)
3245 return 0;
3246
3247 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3248 if (!ra)
3249 return -ENOMEM;
3250
3251 ret = prealloc_file_extent_cluster(inode, cluster);
3252 if (ret)
3253 goto out;
3254
3255 file_ra_state_init(ra, inode->i_mapping);
3256
3257 ret = setup_extent_mapping(inode, cluster->start - offset,
3258 cluster->end - offset, cluster->start);
3259 if (ret)
3260 goto out;
3261
3262 index = (cluster->start - offset) >> PAGE_SHIFT;
3263 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3264 while (index <= last_index) {
3265 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3266 PAGE_SIZE);
3267 if (ret)
3268 goto out;
3269
3270 page = find_lock_page(inode->i_mapping, index);
3271 if (!page) {
3272 page_cache_sync_readahead(inode->i_mapping,
3273 ra, NULL, index,
3274 last_index + 1 - index);
3275 page = find_or_create_page(inode->i_mapping, index,
3276 mask);
3277 if (!page) {
3278 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3279 PAGE_SIZE, true);
3280 btrfs_delalloc_release_extents(BTRFS_I(inode),
3281 PAGE_SIZE);
3282 ret = -ENOMEM;
3283 goto out;
3284 }
3285 }
3286
3287 if (PageReadahead(page)) {
3288 page_cache_async_readahead(inode->i_mapping,
3289 ra, NULL, page, index,
3290 last_index + 1 - index);
3291 }
3292
3293 if (!PageUptodate(page)) {
3294 btrfs_readpage(NULL, page);
3295 lock_page(page);
3296 if (!PageUptodate(page)) {
3297 unlock_page(page);
3298 put_page(page);
3299 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3300 PAGE_SIZE, true);
3301 btrfs_delalloc_release_extents(BTRFS_I(inode),
3302 PAGE_SIZE);
3303 ret = -EIO;
3304 goto out;
3305 }
3306 }
3307
3308 page_start = page_offset(page);
3309 page_end = page_start + PAGE_SIZE - 1;
3310
3311 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3312
3313 set_page_extent_mapped(page);
3314
3315 if (nr < cluster->nr &&
3316 page_start + offset == cluster->boundary[nr]) {
3317 set_extent_bits(&BTRFS_I(inode)->io_tree,
3318 page_start, page_end,
3319 EXTENT_BOUNDARY);
3320 nr++;
3321 }
3322
3323 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3324 NULL);
3325 if (ret) {
3326 unlock_page(page);
3327 put_page(page);
3328 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3329 PAGE_SIZE, true);
3330 btrfs_delalloc_release_extents(BTRFS_I(inode),
3331 PAGE_SIZE);
3332
3333 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3334 page_start, page_end,
3335 EXTENT_LOCKED | EXTENT_BOUNDARY);
3336 goto out;
3337
3338 }
3339 set_page_dirty(page);
3340
3341 unlock_extent(&BTRFS_I(inode)->io_tree,
3342 page_start, page_end);
3343 unlock_page(page);
3344 put_page(page);
3345
3346 index++;
3347 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
3348 balance_dirty_pages_ratelimited(inode->i_mapping);
3349 btrfs_throttle(fs_info);
3350 }
3351 WARN_ON(nr != cluster->nr);
3352out:
3353 kfree(ra);
3354 return ret;
3355}
3356
3357static noinline_for_stack
3358int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3359 struct file_extent_cluster *cluster)
3360{
3361 int ret;
3362
3363 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3364 ret = relocate_file_extent_cluster(inode, cluster);
3365 if (ret)
3366 return ret;
3367 cluster->nr = 0;
3368 }
3369
3370 if (!cluster->nr)
3371 cluster->start = extent_key->objectid;
3372 else
3373 BUG_ON(cluster->nr >= MAX_EXTENTS);
3374 cluster->end = extent_key->objectid + extent_key->offset - 1;
3375 cluster->boundary[cluster->nr] = extent_key->objectid;
3376 cluster->nr++;
3377
3378 if (cluster->nr >= MAX_EXTENTS) {
3379 ret = relocate_file_extent_cluster(inode, cluster);
3380 if (ret)
3381 return ret;
3382 cluster->nr = 0;
3383 }
3384 return 0;
3385}
3386
3387/*
3388 * helper to add a tree block to the list.
3389 * the major work is getting the generation and level of the block
3390 */
3391static int add_tree_block(struct reloc_control *rc,
3392 struct btrfs_key *extent_key,
3393 struct btrfs_path *path,
3394 struct rb_root *blocks)
3395{
3396 struct extent_buffer *eb;
3397 struct btrfs_extent_item *ei;
3398 struct btrfs_tree_block_info *bi;
3399 struct tree_block *block;
3400 struct rb_node *rb_node;
3401 u32 item_size;
3402 int level = -1;
3403 u64 generation;
3404
3405 eb = path->nodes[0];
3406 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3407
3408 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3409 item_size >= sizeof(*ei) + sizeof(*bi)) {
3410 ei = btrfs_item_ptr(eb, path->slots[0],
3411 struct btrfs_extent_item);
3412 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3413 bi = (struct btrfs_tree_block_info *)(ei + 1);
3414 level = btrfs_tree_block_level(eb, bi);
3415 } else {
3416 level = (int)extent_key->offset;
3417 }
3418 generation = btrfs_extent_generation(eb, ei);
3419 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3420 btrfs_print_v0_err(eb->fs_info);
3421 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3422 return -EINVAL;
3423 } else {
3424 BUG();
3425 }
3426
3427 btrfs_release_path(path);
3428
3429 BUG_ON(level == -1);
3430
3431 block = kmalloc(sizeof(*block), GFP_NOFS);
3432 if (!block)
3433 return -ENOMEM;
3434
3435 block->bytenr = extent_key->objectid;
3436 block->key.objectid = rc->extent_root->fs_info->nodesize;
3437 block->key.offset = generation;
3438 block->level = level;
3439 block->key_ready = 0;
3440
3441 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3442 if (rb_node)
3443 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3444
3445 return 0;
3446}
3447
3448/*
3449 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3450 */
3451static int __add_tree_block(struct reloc_control *rc,
3452 u64 bytenr, u32 blocksize,
3453 struct rb_root *blocks)
3454{
3455 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3456 struct btrfs_path *path;
3457 struct btrfs_key key;
3458 int ret;
3459 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3460
3461 if (tree_block_processed(bytenr, rc))
3462 return 0;
3463
3464 if (tree_search(blocks, bytenr))
3465 return 0;
3466
3467 path = btrfs_alloc_path();
3468 if (!path)
3469 return -ENOMEM;
3470again:
3471 key.objectid = bytenr;
3472 if (skinny) {
3473 key.type = BTRFS_METADATA_ITEM_KEY;
3474 key.offset = (u64)-1;
3475 } else {
3476 key.type = BTRFS_EXTENT_ITEM_KEY;
3477 key.offset = blocksize;
3478 }
3479
3480 path->search_commit_root = 1;
3481 path->skip_locking = 1;
3482 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3483 if (ret < 0)
3484 goto out;
3485
3486 if (ret > 0 && skinny) {
3487 if (path->slots[0]) {
3488 path->slots[0]--;
3489 btrfs_item_key_to_cpu(path->nodes[0], &key,
3490 path->slots[0]);
3491 if (key.objectid == bytenr &&
3492 (key.type == BTRFS_METADATA_ITEM_KEY ||
3493 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3494 key.offset == blocksize)))
3495 ret = 0;
3496 }
3497
3498 if (ret) {
3499 skinny = false;
3500 btrfs_release_path(path);
3501 goto again;
3502 }
3503 }
3504 if (ret) {
3505 ASSERT(ret == 1);
3506 btrfs_print_leaf(path->nodes[0]);
3507 btrfs_err(fs_info,
3508 "tree block extent item (%llu) is not found in extent tree",
3509 bytenr);
3510 WARN_ON(1);
3511 ret = -EINVAL;
3512 goto out;
3513 }
3514
3515 ret = add_tree_block(rc, &key, path, blocks);
3516out:
3517 btrfs_free_path(path);
3518 return ret;
3519}
3520
3521/*
3522 * helper to check if the block use full backrefs for pointers in it
3523 */
3524static int block_use_full_backref(struct reloc_control *rc,
3525 struct extent_buffer *eb)
3526{
3527 u64 flags;
3528 int ret;
3529
3530 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3531 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3532 return 1;
3533
3534 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3535 eb->start, btrfs_header_level(eb), 1,
3536 NULL, &flags);
3537 BUG_ON(ret);
3538
3539 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3540 ret = 1;
3541 else
3542 ret = 0;
3543 return ret;
3544}
3545
3546static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3547 struct btrfs_block_group_cache *block_group,
3548 struct inode *inode,
3549 u64 ino)
3550{
3551 struct btrfs_key key;
3552 struct btrfs_root *root = fs_info->tree_root;
3553 struct btrfs_trans_handle *trans;
3554 int ret = 0;
3555
3556 if (inode)
3557 goto truncate;
3558
3559 key.objectid = ino;
3560 key.type = BTRFS_INODE_ITEM_KEY;
3561 key.offset = 0;
3562
3563 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3564 if (IS_ERR(inode))
3565 return -ENOENT;
3566
3567truncate:
3568 ret = btrfs_check_trunc_cache_free_space(fs_info,
3569 &fs_info->global_block_rsv);
3570 if (ret)
3571 goto out;
3572
3573 trans = btrfs_join_transaction(root);
3574 if (IS_ERR(trans)) {
3575 ret = PTR_ERR(trans);
3576 goto out;
3577 }
3578
3579 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3580
3581 btrfs_end_transaction(trans);
3582 btrfs_btree_balance_dirty(fs_info);
3583out:
3584 iput(inode);
3585 return ret;
3586}
3587
3588/*
3589 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3590 * this function scans fs tree to find blocks reference the data extent
3591 */
3592static int find_data_references(struct reloc_control *rc,
3593 struct btrfs_key *extent_key,
3594 struct extent_buffer *leaf,
3595 struct btrfs_extent_data_ref *ref,
3596 struct rb_root *blocks)
3597{
3598 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3599 struct btrfs_path *path;
3600 struct tree_block *block;
3601 struct btrfs_root *root;
3602 struct btrfs_file_extent_item *fi;
3603 struct rb_node *rb_node;
3604 struct btrfs_key key;
3605 u64 ref_root;
3606 u64 ref_objectid;
3607 u64 ref_offset;
3608 u32 ref_count;
3609 u32 nritems;
3610 int err = 0;
3611 int added = 0;
3612 int counted;
3613 int ret;
3614
3615 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3616 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3617 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3618 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3619
3620 /*
3621 * This is an extent belonging to the free space cache, lets just delete
3622 * it and redo the search.
3623 */
3624 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3625 ret = delete_block_group_cache(fs_info, rc->block_group,
3626 NULL, ref_objectid);
3627 if (ret != -ENOENT)
3628 return ret;
3629 ret = 0;
3630 }
3631
3632 path = btrfs_alloc_path();
3633 if (!path)
3634 return -ENOMEM;
3635 path->reada = READA_FORWARD;
3636
3637 root = read_fs_root(fs_info, ref_root);
3638 if (IS_ERR(root)) {
3639 err = PTR_ERR(root);
3640 goto out;
3641 }
3642
3643 key.objectid = ref_objectid;
3644 key.type = BTRFS_EXTENT_DATA_KEY;
3645 if (ref_offset > ((u64)-1 << 32))
3646 key.offset = 0;
3647 else
3648 key.offset = ref_offset;
3649
3650 path->search_commit_root = 1;
3651 path->skip_locking = 1;
3652 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3653 if (ret < 0) {
3654 err = ret;
3655 goto out;
3656 }
3657
3658 leaf = path->nodes[0];
3659 nritems = btrfs_header_nritems(leaf);
3660 /*
3661 * the references in tree blocks that use full backrefs
3662 * are not counted in
3663 */
3664 if (block_use_full_backref(rc, leaf))
3665 counted = 0;
3666 else
3667 counted = 1;
3668 rb_node = tree_search(blocks, leaf->start);
3669 if (rb_node) {
3670 if (counted)
3671 added = 1;
3672 else
3673 path->slots[0] = nritems;
3674 }
3675
3676 while (ref_count > 0) {
3677 while (path->slots[0] >= nritems) {
3678 ret = btrfs_next_leaf(root, path);
3679 if (ret < 0) {
3680 err = ret;
3681 goto out;
3682 }
3683 if (WARN_ON(ret > 0))
3684 goto out;
3685
3686 leaf = path->nodes[0];
3687 nritems = btrfs_header_nritems(leaf);
3688 added = 0;
3689
3690 if (block_use_full_backref(rc, leaf))
3691 counted = 0;
3692 else
3693 counted = 1;
3694 rb_node = tree_search(blocks, leaf->start);
3695 if (rb_node) {
3696 if (counted)
3697 added = 1;
3698 else
3699 path->slots[0] = nritems;
3700 }
3701 }
3702
3703 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3704 if (WARN_ON(key.objectid != ref_objectid ||
3705 key.type != BTRFS_EXTENT_DATA_KEY))
3706 break;
3707
3708 fi = btrfs_item_ptr(leaf, path->slots[0],
3709 struct btrfs_file_extent_item);
3710
3711 if (btrfs_file_extent_type(leaf, fi) ==
3712 BTRFS_FILE_EXTENT_INLINE)
3713 goto next;
3714
3715 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3716 extent_key->objectid)
3717 goto next;
3718
3719 key.offset -= btrfs_file_extent_offset(leaf, fi);
3720 if (key.offset != ref_offset)
3721 goto next;
3722
3723 if (counted)
3724 ref_count--;
3725 if (added)
3726 goto next;
3727
3728 if (!tree_block_processed(leaf->start, rc)) {
3729 block = kmalloc(sizeof(*block), GFP_NOFS);
3730 if (!block) {
3731 err = -ENOMEM;
3732 break;
3733 }
3734 block->bytenr = leaf->start;
3735 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3736 block->level = 0;
3737 block->key_ready = 1;
3738 rb_node = tree_insert(blocks, block->bytenr,
3739 &block->rb_node);
3740 if (rb_node)
3741 backref_tree_panic(rb_node, -EEXIST,
3742 block->bytenr);
3743 }
3744 if (counted)
3745 added = 1;
3746 else
3747 path->slots[0] = nritems;
3748next:
3749 path->slots[0]++;
3750
3751 }
3752out:
3753 btrfs_free_path(path);
3754 return err;
3755}
3756
3757/*
3758 * helper to find all tree blocks that reference a given data extent
3759 */
3760static noinline_for_stack
3761int add_data_references(struct reloc_control *rc,
3762 struct btrfs_key *extent_key,
3763 struct btrfs_path *path,
3764 struct rb_root *blocks)
3765{
3766 struct btrfs_key key;
3767 struct extent_buffer *eb;
3768 struct btrfs_extent_data_ref *dref;
3769 struct btrfs_extent_inline_ref *iref;
3770 unsigned long ptr;
3771 unsigned long end;
3772 u32 blocksize = rc->extent_root->fs_info->nodesize;
3773 int ret = 0;
3774 int err = 0;
3775
3776 eb = path->nodes[0];
3777 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3778 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3779 ptr += sizeof(struct btrfs_extent_item);
3780
3781 while (ptr < end) {
3782 iref = (struct btrfs_extent_inline_ref *)ptr;
3783 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3784 BTRFS_REF_TYPE_DATA);
3785 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3786 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3787 ret = __add_tree_block(rc, key.offset, blocksize,
3788 blocks);
3789 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3790 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3791 ret = find_data_references(rc, extent_key,
3792 eb, dref, blocks);
3793 } else {
3794 ret = -EUCLEAN;
3795 btrfs_err(rc->extent_root->fs_info,
3796 "extent %llu slot %d has an invalid inline ref type",
3797 eb->start, path->slots[0]);
3798 }
3799 if (ret) {
3800 err = ret;
3801 goto out;
3802 }
3803 ptr += btrfs_extent_inline_ref_size(key.type);
3804 }
3805 WARN_ON(ptr > end);
3806
3807 while (1) {
3808 cond_resched();
3809 eb = path->nodes[0];
3810 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3811 ret = btrfs_next_leaf(rc->extent_root, path);
3812 if (ret < 0) {
3813 err = ret;
3814 break;
3815 }
3816 if (ret > 0)
3817 break;
3818 eb = path->nodes[0];
3819 }
3820
3821 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3822 if (key.objectid != extent_key->objectid)
3823 break;
3824
3825 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3826 ret = __add_tree_block(rc, key.offset, blocksize,
3827 blocks);
3828 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3829 dref = btrfs_item_ptr(eb, path->slots[0],
3830 struct btrfs_extent_data_ref);
3831 ret = find_data_references(rc, extent_key,
3832 eb, dref, blocks);
3833 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3834 btrfs_print_v0_err(eb->fs_info);
3835 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3836 ret = -EINVAL;
3837 } else {
3838 ret = 0;
3839 }
3840 if (ret) {
3841 err = ret;
3842 break;
3843 }
3844 path->slots[0]++;
3845 }
3846out:
3847 btrfs_release_path(path);
3848 if (err)
3849 free_block_list(blocks);
3850 return err;
3851}
3852
3853/*
3854 * helper to find next unprocessed extent
3855 */
3856static noinline_for_stack
3857int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3858 struct btrfs_key *extent_key)
3859{
3860 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3861 struct btrfs_key key;
3862 struct extent_buffer *leaf;
3863 u64 start, end, last;
3864 int ret;
3865
3866 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3867 while (1) {
3868 cond_resched();
3869 if (rc->search_start >= last) {
3870 ret = 1;
3871 break;
3872 }
3873
3874 key.objectid = rc->search_start;
3875 key.type = BTRFS_EXTENT_ITEM_KEY;
3876 key.offset = 0;
3877
3878 path->search_commit_root = 1;
3879 path->skip_locking = 1;
3880 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3881 0, 0);
3882 if (ret < 0)
3883 break;
3884next:
3885 leaf = path->nodes[0];
3886 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3887 ret = btrfs_next_leaf(rc->extent_root, path);
3888 if (ret != 0)
3889 break;
3890 leaf = path->nodes[0];
3891 }
3892
3893 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3894 if (key.objectid >= last) {
3895 ret = 1;
3896 break;
3897 }
3898
3899 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3900 key.type != BTRFS_METADATA_ITEM_KEY) {
3901 path->slots[0]++;
3902 goto next;
3903 }
3904
3905 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3906 key.objectid + key.offset <= rc->search_start) {
3907 path->slots[0]++;
3908 goto next;
3909 }
3910
3911 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3912 key.objectid + fs_info->nodesize <=
3913 rc->search_start) {
3914 path->slots[0]++;
3915 goto next;
3916 }
3917
3918 ret = find_first_extent_bit(&rc->processed_blocks,
3919 key.objectid, &start, &end,
3920 EXTENT_DIRTY, NULL);
3921
3922 if (ret == 0 && start <= key.objectid) {
3923 btrfs_release_path(path);
3924 rc->search_start = end + 1;
3925 } else {
3926 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3927 rc->search_start = key.objectid + key.offset;
3928 else
3929 rc->search_start = key.objectid +
3930 fs_info->nodesize;
3931 memcpy(extent_key, &key, sizeof(key));
3932 return 0;
3933 }
3934 }
3935 btrfs_release_path(path);
3936 return ret;
3937}
3938
3939static void set_reloc_control(struct reloc_control *rc)
3940{
3941 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3942
3943 mutex_lock(&fs_info->reloc_mutex);
3944 fs_info->reloc_ctl = rc;
3945 mutex_unlock(&fs_info->reloc_mutex);
3946}
3947
3948static void unset_reloc_control(struct reloc_control *rc)
3949{
3950 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3951
3952 mutex_lock(&fs_info->reloc_mutex);
3953 fs_info->reloc_ctl = NULL;
3954 mutex_unlock(&fs_info->reloc_mutex);
3955}
3956
3957static int check_extent_flags(u64 flags)
3958{
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_EXTENT_FLAG_TREE_BLOCK))
3964 return 1;
3965 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3966 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3967 return 1;
3968 return 0;
3969}
3970
3971static noinline_for_stack
3972int prepare_to_relocate(struct reloc_control *rc)
3973{
3974 struct btrfs_trans_handle *trans;
3975 int ret;
3976
3977 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3978 BTRFS_BLOCK_RSV_TEMP);
3979 if (!rc->block_rsv)
3980 return -ENOMEM;
3981
3982 memset(&rc->cluster, 0, sizeof(rc->cluster));
3983 rc->search_start = rc->block_group->key.objectid;
3984 rc->extents_found = 0;
3985 rc->nodes_relocated = 0;
3986 rc->merging_rsv_size = 0;
3987 rc->reserved_bytes = 0;
3988 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3989 RELOCATION_RESERVED_NODES;
3990 ret = btrfs_block_rsv_refill(rc->extent_root,
3991 rc->block_rsv, rc->block_rsv->size,
3992 BTRFS_RESERVE_FLUSH_ALL);
3993 if (ret)
3994 return ret;
3995
3996 rc->create_reloc_tree = 1;
3997 set_reloc_control(rc);
3998
3999 trans = btrfs_join_transaction(rc->extent_root);
4000 if (IS_ERR(trans)) {
4001 unset_reloc_control(rc);
4002 /*
4003 * extent tree is not a ref_cow tree and has no reloc_root to
4004 * cleanup. And callers are responsible to free the above
4005 * block rsv.
4006 */
4007 return PTR_ERR(trans);
4008 }
4009 btrfs_commit_transaction(trans);
4010 return 0;
4011}
4012
4013static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4014{
4015 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4016 struct rb_root blocks = RB_ROOT;
4017 struct btrfs_key key;
4018 struct btrfs_trans_handle *trans = NULL;
4019 struct btrfs_path *path;
4020 struct btrfs_extent_item *ei;
4021 u64 flags;
4022 u32 item_size;
4023 int ret;
4024 int err = 0;
4025 int progress = 0;
4026
4027 path = btrfs_alloc_path();
4028 if (!path)
4029 return -ENOMEM;
4030 path->reada = READA_FORWARD;
4031
4032 ret = prepare_to_relocate(rc);
4033 if (ret) {
4034 err = ret;
4035 goto out_free;
4036 }
4037
4038 while (1) {
4039 rc->reserved_bytes = 0;
4040 ret = btrfs_block_rsv_refill(rc->extent_root,
4041 rc->block_rsv, rc->block_rsv->size,
4042 BTRFS_RESERVE_FLUSH_ALL);
4043 if (ret) {
4044 err = ret;
4045 break;
4046 }
4047 progress++;
4048 trans = btrfs_start_transaction(rc->extent_root, 0);
4049 if (IS_ERR(trans)) {
4050 err = PTR_ERR(trans);
4051 trans = NULL;
4052 break;
4053 }
4054restart:
4055 if (update_backref_cache(trans, &rc->backref_cache)) {
4056 btrfs_end_transaction(trans);
4057 trans = NULL;
4058 continue;
4059 }
4060
4061 ret = find_next_extent(rc, path, &key);
4062 if (ret < 0)
4063 err = ret;
4064 if (ret != 0)
4065 break;
4066
4067 rc->extents_found++;
4068
4069 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4070 struct btrfs_extent_item);
4071 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4072 if (item_size >= sizeof(*ei)) {
4073 flags = btrfs_extent_flags(path->nodes[0], ei);
4074 ret = check_extent_flags(flags);
4075 BUG_ON(ret);
4076 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4077 err = -EINVAL;
4078 btrfs_print_v0_err(trans->fs_info);
4079 btrfs_abort_transaction(trans, err);
4080 break;
4081 } else {
4082 BUG();
4083 }
4084
4085 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4086 ret = add_tree_block(rc, &key, path, &blocks);
4087 } else if (rc->stage == UPDATE_DATA_PTRS &&
4088 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4089 ret = add_data_references(rc, &key, path, &blocks);
4090 } else {
4091 btrfs_release_path(path);
4092 ret = 0;
4093 }
4094 if (ret < 0) {
4095 err = ret;
4096 break;
4097 }
4098
4099 if (!RB_EMPTY_ROOT(&blocks)) {
4100 ret = relocate_tree_blocks(trans, rc, &blocks);
4101 if (ret < 0) {
4102 /*
4103 * if we fail to relocate tree blocks, force to update
4104 * backref cache when committing transaction.
4105 */
4106 rc->backref_cache.last_trans = trans->transid - 1;
4107
4108 if (ret != -EAGAIN) {
4109 err = ret;
4110 break;
4111 }
4112 rc->extents_found--;
4113 rc->search_start = key.objectid;
4114 }
4115 }
4116
4117 btrfs_end_transaction_throttle(trans);
4118 btrfs_btree_balance_dirty(fs_info);
4119 trans = NULL;
4120
4121 if (rc->stage == MOVE_DATA_EXTENTS &&
4122 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4123 rc->found_file_extent = 1;
4124 ret = relocate_data_extent(rc->data_inode,
4125 &key, &rc->cluster);
4126 if (ret < 0) {
4127 err = ret;
4128 break;
4129 }
4130 }
4131 }
4132 if (trans && progress && err == -ENOSPC) {
4133 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4134 if (ret == 1) {
4135 err = 0;
4136 progress = 0;
4137 goto restart;
4138 }
4139 }
4140
4141 btrfs_release_path(path);
4142 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4143
4144 if (trans) {
4145 btrfs_end_transaction_throttle(trans);
4146 btrfs_btree_balance_dirty(fs_info);
4147 }
4148
4149 if (!err) {
4150 ret = relocate_file_extent_cluster(rc->data_inode,
4151 &rc->cluster);
4152 if (ret < 0)
4153 err = ret;
4154 }
4155
4156 rc->create_reloc_tree = 0;
4157 set_reloc_control(rc);
4158
4159 backref_cache_cleanup(&rc->backref_cache);
4160 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4161
4162 err = prepare_to_merge(rc, err);
4163
4164 merge_reloc_roots(rc);
4165
4166 rc->merge_reloc_tree = 0;
4167 unset_reloc_control(rc);
4168 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4169
4170 /* get rid of pinned extents */
4171 trans = btrfs_join_transaction(rc->extent_root);
4172 if (IS_ERR(trans)) {
4173 err = PTR_ERR(trans);
4174 goto out_free;
4175 }
4176 btrfs_commit_transaction(trans);
4177 ret = clean_dirty_subvols(rc);
4178 if (ret < 0 && !err)
4179 err = ret;
4180out_free:
4181 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4182 btrfs_free_path(path);
4183 return err;
4184}
4185
4186static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4187 struct btrfs_root *root, u64 objectid)
4188{
4189 struct btrfs_path *path;
4190 struct btrfs_inode_item *item;
4191 struct extent_buffer *leaf;
4192 int ret;
4193
4194 path = btrfs_alloc_path();
4195 if (!path)
4196 return -ENOMEM;
4197
4198 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4199 if (ret)
4200 goto out;
4201
4202 leaf = path->nodes[0];
4203 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4204 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4205 btrfs_set_inode_generation(leaf, item, 1);
4206 btrfs_set_inode_size(leaf, item, 0);
4207 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4208 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4209 BTRFS_INODE_PREALLOC);
4210 btrfs_mark_buffer_dirty(leaf);
4211out:
4212 btrfs_free_path(path);
4213 return ret;
4214}
4215
4216/*
4217 * helper to create inode for data relocation.
4218 * the inode is in data relocation tree and its link count is 0
4219 */
4220static noinline_for_stack
4221struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4222 struct btrfs_block_group_cache *group)
4223{
4224 struct inode *inode = NULL;
4225 struct btrfs_trans_handle *trans;
4226 struct btrfs_root *root;
4227 struct btrfs_key key;
4228 u64 objectid;
4229 int err = 0;
4230
4231 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4232 if (IS_ERR(root))
4233 return ERR_CAST(root);
4234
4235 trans = btrfs_start_transaction(root, 6);
4236 if (IS_ERR(trans))
4237 return ERR_CAST(trans);
4238
4239 err = btrfs_find_free_objectid(root, &objectid);
4240 if (err)
4241 goto out;
4242
4243 err = __insert_orphan_inode(trans, root, objectid);
4244 BUG_ON(err);
4245
4246 key.objectid = objectid;
4247 key.type = BTRFS_INODE_ITEM_KEY;
4248 key.offset = 0;
4249 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4250 BUG_ON(IS_ERR(inode));
4251 BTRFS_I(inode)->index_cnt = group->key.objectid;
4252
4253 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4254out:
4255 btrfs_end_transaction(trans);
4256 btrfs_btree_balance_dirty(fs_info);
4257 if (err) {
4258 if (inode)
4259 iput(inode);
4260 inode = ERR_PTR(err);
4261 }
4262 return inode;
4263}
4264
4265static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4266{
4267 struct reloc_control *rc;
4268
4269 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4270 if (!rc)
4271 return NULL;
4272
4273 INIT_LIST_HEAD(&rc->reloc_roots);
4274 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4275 backref_cache_init(&rc->backref_cache);
4276 mapping_tree_init(&rc->reloc_root_tree);
4277 extent_io_tree_init(fs_info, &rc->processed_blocks,
4278 IO_TREE_RELOC_BLOCKS, NULL);
4279 return rc;
4280}
4281
4282/*
4283 * Print the block group being relocated
4284 */
4285static void describe_relocation(struct btrfs_fs_info *fs_info,
4286 struct btrfs_block_group_cache *block_group)
4287{
4288 char buf[128] = {'\0'};
4289
4290 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4291
4292 btrfs_info(fs_info,
4293 "relocating block group %llu flags %s",
4294 block_group->key.objectid, buf);
4295}
4296
4297/*
4298 * function to relocate all extents in a block group.
4299 */
4300int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4301{
4302 struct btrfs_block_group_cache *bg;
4303 struct btrfs_root *extent_root = fs_info->extent_root;
4304 struct reloc_control *rc;
4305 struct inode *inode;
4306 struct btrfs_path *path;
4307 int ret;
4308 int rw = 0;
4309 int err = 0;
4310
4311 bg = btrfs_lookup_block_group(fs_info, group_start);
4312 if (!bg)
4313 return -ENOENT;
4314
4315 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4316 btrfs_put_block_group(bg);
4317 return -ETXTBSY;
4318 }
4319
4320 rc = alloc_reloc_control(fs_info);
4321 if (!rc) {
4322 btrfs_put_block_group(bg);
4323 return -ENOMEM;
4324 }
4325
4326 rc->extent_root = extent_root;
4327 rc->block_group = bg;
4328
4329 ret = btrfs_inc_block_group_ro(rc->block_group);
4330 if (ret) {
4331 err = ret;
4332 goto out;
4333 }
4334 rw = 1;
4335
4336 path = btrfs_alloc_path();
4337 if (!path) {
4338 err = -ENOMEM;
4339 goto out;
4340 }
4341
4342 inode = lookup_free_space_inode(rc->block_group, path);
4343 btrfs_free_path(path);
4344
4345 if (!IS_ERR(inode))
4346 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4347 else
4348 ret = PTR_ERR(inode);
4349
4350 if (ret && ret != -ENOENT) {
4351 err = ret;
4352 goto out;
4353 }
4354
4355 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4356 if (IS_ERR(rc->data_inode)) {
4357 err = PTR_ERR(rc->data_inode);
4358 rc->data_inode = NULL;
4359 goto out;
4360 }
4361
4362 describe_relocation(fs_info, rc->block_group);
4363
4364 btrfs_wait_block_group_reservations(rc->block_group);
4365 btrfs_wait_nocow_writers(rc->block_group);
4366 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4367 rc->block_group->key.objectid,
4368 rc->block_group->key.offset);
4369
4370 while (1) {
4371 mutex_lock(&fs_info->cleaner_mutex);
4372 ret = relocate_block_group(rc);
4373 mutex_unlock(&fs_info->cleaner_mutex);
4374 if (ret < 0)
4375 err = ret;
4376
4377 /*
4378 * We may have gotten ENOSPC after we already dirtied some
4379 * extents. If writeout happens while we're relocating a
4380 * different block group we could end up hitting the
4381 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4382 * btrfs_reloc_cow_block. Make sure we write everything out
4383 * properly so we don't trip over this problem, and then break
4384 * out of the loop if we hit an error.
4385 */
4386 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4387 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4388 (u64)-1);
4389 if (ret)
4390 err = ret;
4391 invalidate_mapping_pages(rc->data_inode->i_mapping,
4392 0, -1);
4393 rc->stage = UPDATE_DATA_PTRS;
4394 }
4395
4396 if (err < 0)
4397 goto out;
4398
4399 if (rc->extents_found == 0)
4400 break;
4401
4402 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4403
4404 }
4405
4406 WARN_ON(rc->block_group->pinned > 0);
4407 WARN_ON(rc->block_group->reserved > 0);
4408 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4409out:
4410 if (err && rw)
4411 btrfs_dec_block_group_ro(rc->block_group);
4412 iput(rc->data_inode);
4413 btrfs_put_block_group(rc->block_group);
4414 kfree(rc);
4415 return err;
4416}
4417
4418static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4419{
4420 struct btrfs_fs_info *fs_info = root->fs_info;
4421 struct btrfs_trans_handle *trans;
4422 int ret, err;
4423
4424 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4425 if (IS_ERR(trans))
4426 return PTR_ERR(trans);
4427
4428 memset(&root->root_item.drop_progress, 0,
4429 sizeof(root->root_item.drop_progress));
4430 root->root_item.drop_level = 0;
4431 btrfs_set_root_refs(&root->root_item, 0);
4432 ret = btrfs_update_root(trans, fs_info->tree_root,
4433 &root->root_key, &root->root_item);
4434
4435 err = btrfs_end_transaction(trans);
4436 if (err)
4437 return err;
4438 return ret;
4439}
4440
4441/*
4442 * recover relocation interrupted by system crash.
4443 *
4444 * this function resumes merging reloc trees with corresponding fs trees.
4445 * this is important for keeping the sharing of tree blocks
4446 */
4447int btrfs_recover_relocation(struct btrfs_root *root)
4448{
4449 struct btrfs_fs_info *fs_info = root->fs_info;
4450 LIST_HEAD(reloc_roots);
4451 struct btrfs_key key;
4452 struct btrfs_root *fs_root;
4453 struct btrfs_root *reloc_root;
4454 struct btrfs_path *path;
4455 struct extent_buffer *leaf;
4456 struct reloc_control *rc = NULL;
4457 struct btrfs_trans_handle *trans;
4458 int ret;
4459 int err = 0;
4460
4461 path = btrfs_alloc_path();
4462 if (!path)
4463 return -ENOMEM;
4464 path->reada = READA_BACK;
4465
4466 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4467 key.type = BTRFS_ROOT_ITEM_KEY;
4468 key.offset = (u64)-1;
4469
4470 while (1) {
4471 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4472 path, 0, 0);
4473 if (ret < 0) {
4474 err = ret;
4475 goto out;
4476 }
4477 if (ret > 0) {
4478 if (path->slots[0] == 0)
4479 break;
4480 path->slots[0]--;
4481 }
4482 leaf = path->nodes[0];
4483 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4484 btrfs_release_path(path);
4485
4486 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4487 key.type != BTRFS_ROOT_ITEM_KEY)
4488 break;
4489
4490 reloc_root = btrfs_read_fs_root(root, &key);
4491 if (IS_ERR(reloc_root)) {
4492 err = PTR_ERR(reloc_root);
4493 goto out;
4494 }
4495
4496 list_add(&reloc_root->root_list, &reloc_roots);
4497
4498 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4499 fs_root = read_fs_root(fs_info,
4500 reloc_root->root_key.offset);
4501 if (IS_ERR(fs_root)) {
4502 ret = PTR_ERR(fs_root);
4503 if (ret != -ENOENT) {
4504 err = ret;
4505 goto out;
4506 }
4507 ret = mark_garbage_root(reloc_root);
4508 if (ret < 0) {
4509 err = ret;
4510 goto out;
4511 }
4512 }
4513 }
4514
4515 if (key.offset == 0)
4516 break;
4517
4518 key.offset--;
4519 }
4520 btrfs_release_path(path);
4521
4522 if (list_empty(&reloc_roots))
4523 goto out;
4524
4525 rc = alloc_reloc_control(fs_info);
4526 if (!rc) {
4527 err = -ENOMEM;
4528 goto out;
4529 }
4530
4531 rc->extent_root = fs_info->extent_root;
4532
4533 set_reloc_control(rc);
4534
4535 trans = btrfs_join_transaction(rc->extent_root);
4536 if (IS_ERR(trans)) {
4537 unset_reloc_control(rc);
4538 err = PTR_ERR(trans);
4539 goto out_free;
4540 }
4541
4542 rc->merge_reloc_tree = 1;
4543
4544 while (!list_empty(&reloc_roots)) {
4545 reloc_root = list_entry(reloc_roots.next,
4546 struct btrfs_root, root_list);
4547 list_del(&reloc_root->root_list);
4548
4549 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4550 list_add_tail(&reloc_root->root_list,
4551 &rc->reloc_roots);
4552 continue;
4553 }
4554
4555 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4556 if (IS_ERR(fs_root)) {
4557 err = PTR_ERR(fs_root);
4558 goto out_free;
4559 }
4560
4561 err = __add_reloc_root(reloc_root);
4562 BUG_ON(err < 0); /* -ENOMEM or logic error */
4563 fs_root->reloc_root = reloc_root;
4564 }
4565
4566 err = btrfs_commit_transaction(trans);
4567 if (err)
4568 goto out_free;
4569
4570 merge_reloc_roots(rc);
4571
4572 unset_reloc_control(rc);
4573
4574 trans = btrfs_join_transaction(rc->extent_root);
4575 if (IS_ERR(trans)) {
4576 err = PTR_ERR(trans);
4577 goto out_free;
4578 }
4579 err = btrfs_commit_transaction(trans);
4580
4581 ret = clean_dirty_subvols(rc);
4582 if (ret < 0 && !err)
4583 err = ret;
4584out_free:
4585 kfree(rc);
4586out:
4587 if (!list_empty(&reloc_roots))
4588 free_reloc_roots(&reloc_roots);
4589
4590 btrfs_free_path(path);
4591
4592 if (err == 0) {
4593 /* cleanup orphan inode in data relocation tree */
4594 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4595 if (IS_ERR(fs_root))
4596 err = PTR_ERR(fs_root);
4597 else
4598 err = btrfs_orphan_cleanup(fs_root);
4599 }
4600 return err;
4601}
4602
4603/*
4604 * helper to add ordered checksum for data relocation.
4605 *
4606 * cloning checksum properly handles the nodatasum extents.
4607 * it also saves CPU time to re-calculate the checksum.
4608 */
4609int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4610{
4611 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4612 struct btrfs_ordered_sum *sums;
4613 struct btrfs_ordered_extent *ordered;
4614 int ret;
4615 u64 disk_bytenr;
4616 u64 new_bytenr;
4617 LIST_HEAD(list);
4618
4619 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4620 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4621
4622 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4623 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4624 disk_bytenr + len - 1, &list, 0);
4625 if (ret)
4626 goto out;
4627
4628 while (!list_empty(&list)) {
4629 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4630 list_del_init(&sums->list);
4631
4632 /*
4633 * We need to offset the new_bytenr based on where the csum is.
4634 * We need to do this because we will read in entire prealloc
4635 * extents but we may have written to say the middle of the
4636 * prealloc extent, so we need to make sure the csum goes with
4637 * the right disk offset.
4638 *
4639 * We can do this because the data reloc inode refers strictly
4640 * to the on disk bytes, so we don't have to worry about
4641 * disk_len vs real len like with real inodes since it's all
4642 * disk length.
4643 */
4644 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4645 sums->bytenr = new_bytenr;
4646
4647 btrfs_add_ordered_sum(ordered, sums);
4648 }
4649out:
4650 btrfs_put_ordered_extent(ordered);
4651 return ret;
4652}
4653
4654int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4655 struct btrfs_root *root, struct extent_buffer *buf,
4656 struct extent_buffer *cow)
4657{
4658 struct btrfs_fs_info *fs_info = root->fs_info;
4659 struct reloc_control *rc;
4660 struct backref_node *node;
4661 int first_cow = 0;
4662 int level;
4663 int ret = 0;
4664
4665 rc = fs_info->reloc_ctl;
4666 if (!rc)
4667 return 0;
4668
4669 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4670 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4671
4672 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4673 if (buf == root->node)
4674 __update_reloc_root(root, cow->start);
4675 }
4676
4677 level = btrfs_header_level(buf);
4678 if (btrfs_header_generation(buf) <=
4679 btrfs_root_last_snapshot(&root->root_item))
4680 first_cow = 1;
4681
4682 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4683 rc->create_reloc_tree) {
4684 WARN_ON(!first_cow && level == 0);
4685
4686 node = rc->backref_cache.path[level];
4687 BUG_ON(node->bytenr != buf->start &&
4688 node->new_bytenr != buf->start);
4689
4690 drop_node_buffer(node);
4691 extent_buffer_get(cow);
4692 node->eb = cow;
4693 node->new_bytenr = cow->start;
4694
4695 if (!node->pending) {
4696 list_move_tail(&node->list,
4697 &rc->backref_cache.pending[level]);
4698 node->pending = 1;
4699 }
4700
4701 if (first_cow)
4702 __mark_block_processed(rc, node);
4703
4704 if (first_cow && level > 0)
4705 rc->nodes_relocated += buf->len;
4706 }
4707
4708 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4709 ret = replace_file_extents(trans, rc, root, cow);
4710 return ret;
4711}
4712
4713/*
4714 * called before creating snapshot. it calculates metadata reservation
4715 * required for relocating tree blocks in the snapshot
4716 */
4717void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4718 u64 *bytes_to_reserve)
4719{
4720 struct btrfs_root *root = pending->root;
4721 struct reloc_control *rc = root->fs_info->reloc_ctl;
4722
4723 if (!root->reloc_root || !rc)
4724 return;
4725
4726 if (!rc->merge_reloc_tree)
4727 return;
4728
4729 root = root->reloc_root;
4730 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4731 /*
4732 * relocation is in the stage of merging trees. the space
4733 * used by merging a reloc tree is twice the size of
4734 * relocated tree nodes in the worst case. half for cowing
4735 * the reloc tree, half for cowing the fs tree. the space
4736 * used by cowing the reloc tree will be freed after the
4737 * tree is dropped. if we create snapshot, cowing the fs
4738 * tree may use more space than it frees. so we need
4739 * reserve extra space.
4740 */
4741 *bytes_to_reserve += rc->nodes_relocated;
4742}
4743
4744/*
4745 * called after snapshot is created. migrate block reservation
4746 * and create reloc root for the newly created snapshot
4747 */
4748int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4749 struct btrfs_pending_snapshot *pending)
4750{
4751 struct btrfs_root *root = pending->root;
4752 struct btrfs_root *reloc_root;
4753 struct btrfs_root *new_root;
4754 struct reloc_control *rc = root->fs_info->reloc_ctl;
4755 int ret;
4756
4757 if (!root->reloc_root || !rc)
4758 return 0;
4759
4760 rc = root->fs_info->reloc_ctl;
4761 rc->merging_rsv_size += rc->nodes_relocated;
4762
4763 if (rc->merge_reloc_tree) {
4764 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4765 rc->block_rsv,
4766 rc->nodes_relocated, true);
4767 if (ret)
4768 return ret;
4769 }
4770
4771 new_root = pending->snap;
4772 reloc_root = create_reloc_root(trans, root->reloc_root,
4773 new_root->root_key.objectid);
4774 if (IS_ERR(reloc_root))
4775 return PTR_ERR(reloc_root);
4776
4777 ret = __add_reloc_root(reloc_root);
4778 BUG_ON(ret < 0);
4779 new_root->reloc_root = reloc_root;
4780
4781 if (rc->create_reloc_tree)
4782 ret = clone_backref_node(trans, rc, root, reloc_root);
4783 return ret;
4784}
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 <linux/error-injection.h>
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "volumes.h"
17#include "locking.h"
18#include "btrfs_inode.h"
19#include "async-thread.h"
20#include "free-space-cache.h"
21#include "qgroup.h"
22#include "print-tree.h"
23#include "delalloc-space.h"
24#include "block-group.h"
25#include "backref.h"
26#include "misc.h"
27#include "subpage.h"
28#include "zoned.h"
29#include "inode-item.h"
30#include "space-info.h"
31#include "fs.h"
32#include "accessors.h"
33#include "extent-tree.h"
34#include "root-tree.h"
35#include "file-item.h"
36#include "relocation.h"
37#include "super.h"
38#include "tree-checker.h"
39
40/*
41 * Relocation overview
42 *
43 * [What does relocation do]
44 *
45 * The objective of relocation is to relocate all extents of the target block
46 * group to other block groups.
47 * This is utilized by resize (shrink only), profile converting, compacting
48 * space, or balance routine to spread chunks over devices.
49 *
50 * Before | After
51 * ------------------------------------------------------------------
52 * BG A: 10 data extents | BG A: deleted
53 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
54 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
55 *
56 * [How does relocation work]
57 *
58 * 1. Mark the target block group read-only
59 * New extents won't be allocated from the target block group.
60 *
61 * 2.1 Record each extent in the target block group
62 * To build a proper map of extents to be relocated.
63 *
64 * 2.2 Build data reloc tree and reloc trees
65 * Data reloc tree will contain an inode, recording all newly relocated
66 * data extents.
67 * There will be only one data reloc tree for one data block group.
68 *
69 * Reloc tree will be a special snapshot of its source tree, containing
70 * relocated tree blocks.
71 * Each tree referring to a tree block in target block group will get its
72 * reloc tree built.
73 *
74 * 2.3 Swap source tree with its corresponding reloc tree
75 * Each involved tree only refers to new extents after swap.
76 *
77 * 3. Cleanup reloc trees and data reloc tree.
78 * As old extents in the target block group are still referenced by reloc
79 * trees, we need to clean them up before really freeing the target block
80 * group.
81 *
82 * The main complexity is in steps 2.2 and 2.3.
83 *
84 * The entry point of relocation is relocate_block_group() function.
85 */
86
87#define RELOCATION_RESERVED_NODES 256
88/*
89 * map address of tree root to tree
90 */
91struct mapping_node {
92 struct {
93 struct rb_node rb_node;
94 u64 bytenr;
95 }; /* Use rb_simle_node for search/insert */
96 void *data;
97};
98
99struct mapping_tree {
100 struct rb_root rb_root;
101 spinlock_t lock;
102};
103
104/*
105 * present a tree block to process
106 */
107struct tree_block {
108 struct {
109 struct rb_node rb_node;
110 u64 bytenr;
111 }; /* Use rb_simple_node for search/insert */
112 u64 owner;
113 struct btrfs_key key;
114 unsigned int level:8;
115 unsigned int key_ready:1;
116};
117
118#define MAX_EXTENTS 128
119
120struct file_extent_cluster {
121 u64 start;
122 u64 end;
123 u64 boundary[MAX_EXTENTS];
124 unsigned int nr;
125};
126
127struct reloc_control {
128 /* block group to relocate */
129 struct btrfs_block_group *block_group;
130 /* extent tree */
131 struct btrfs_root *extent_root;
132 /* inode for moving data */
133 struct inode *data_inode;
134
135 struct btrfs_block_rsv *block_rsv;
136
137 struct btrfs_backref_cache backref_cache;
138
139 struct file_extent_cluster cluster;
140 /* tree blocks have been processed */
141 struct extent_io_tree processed_blocks;
142 /* map start of tree root to corresponding reloc tree */
143 struct mapping_tree reloc_root_tree;
144 /* list of reloc trees */
145 struct list_head reloc_roots;
146 /* list of subvolume trees that get relocated */
147 struct list_head dirty_subvol_roots;
148 /* size of metadata reservation for merging reloc trees */
149 u64 merging_rsv_size;
150 /* size of relocated tree nodes */
151 u64 nodes_relocated;
152 /* reserved size for block group relocation*/
153 u64 reserved_bytes;
154
155 u64 search_start;
156 u64 extents_found;
157
158 unsigned int stage:8;
159 unsigned int create_reloc_tree:1;
160 unsigned int merge_reloc_tree:1;
161 unsigned int found_file_extent:1;
162};
163
164/* stages of data relocation */
165#define MOVE_DATA_EXTENTS 0
166#define UPDATE_DATA_PTRS 1
167
168static void mark_block_processed(struct reloc_control *rc,
169 struct btrfs_backref_node *node)
170{
171 u32 blocksize;
172
173 if (node->level == 0 ||
174 in_range(node->bytenr, rc->block_group->start,
175 rc->block_group->length)) {
176 blocksize = rc->extent_root->fs_info->nodesize;
177 set_extent_bits(&rc->processed_blocks, node->bytenr,
178 node->bytenr + blocksize - 1, EXTENT_DIRTY);
179 }
180 node->processed = 1;
181}
182
183
184static void mapping_tree_init(struct mapping_tree *tree)
185{
186 tree->rb_root = RB_ROOT;
187 spin_lock_init(&tree->lock);
188}
189
190/*
191 * walk up backref nodes until reach node presents tree root
192 */
193static struct btrfs_backref_node *walk_up_backref(
194 struct btrfs_backref_node *node,
195 struct btrfs_backref_edge *edges[], int *index)
196{
197 struct btrfs_backref_edge *edge;
198 int idx = *index;
199
200 while (!list_empty(&node->upper)) {
201 edge = list_entry(node->upper.next,
202 struct btrfs_backref_edge, list[LOWER]);
203 edges[idx++] = edge;
204 node = edge->node[UPPER];
205 }
206 BUG_ON(node->detached);
207 *index = idx;
208 return node;
209}
210
211/*
212 * walk down backref nodes to find start of next reference path
213 */
214static struct btrfs_backref_node *walk_down_backref(
215 struct btrfs_backref_edge *edges[], int *index)
216{
217 struct btrfs_backref_edge *edge;
218 struct btrfs_backref_node *lower;
219 int idx = *index;
220
221 while (idx > 0) {
222 edge = edges[idx - 1];
223 lower = edge->node[LOWER];
224 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
225 idx--;
226 continue;
227 }
228 edge = list_entry(edge->list[LOWER].next,
229 struct btrfs_backref_edge, list[LOWER]);
230 edges[idx - 1] = edge;
231 *index = idx;
232 return edge->node[UPPER];
233 }
234 *index = 0;
235 return NULL;
236}
237
238static void update_backref_node(struct btrfs_backref_cache *cache,
239 struct btrfs_backref_node *node, u64 bytenr)
240{
241 struct rb_node *rb_node;
242 rb_erase(&node->rb_node, &cache->rb_root);
243 node->bytenr = bytenr;
244 rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
245 if (rb_node)
246 btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
247}
248
249/*
250 * update backref cache after a transaction commit
251 */
252static int update_backref_cache(struct btrfs_trans_handle *trans,
253 struct btrfs_backref_cache *cache)
254{
255 struct btrfs_backref_node *node;
256 int level = 0;
257
258 if (cache->last_trans == 0) {
259 cache->last_trans = trans->transid;
260 return 0;
261 }
262
263 if (cache->last_trans == trans->transid)
264 return 0;
265
266 /*
267 * detached nodes are used to avoid unnecessary backref
268 * lookup. transaction commit changes the extent tree.
269 * so the detached nodes are no longer useful.
270 */
271 while (!list_empty(&cache->detached)) {
272 node = list_entry(cache->detached.next,
273 struct btrfs_backref_node, list);
274 btrfs_backref_cleanup_node(cache, node);
275 }
276
277 while (!list_empty(&cache->changed)) {
278 node = list_entry(cache->changed.next,
279 struct btrfs_backref_node, list);
280 list_del_init(&node->list);
281 BUG_ON(node->pending);
282 update_backref_node(cache, node, node->new_bytenr);
283 }
284
285 /*
286 * some nodes can be left in the pending list if there were
287 * errors during processing the pending nodes.
288 */
289 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
290 list_for_each_entry(node, &cache->pending[level], list) {
291 BUG_ON(!node->pending);
292 if (node->bytenr == node->new_bytenr)
293 continue;
294 update_backref_node(cache, node, node->new_bytenr);
295 }
296 }
297
298 cache->last_trans = 0;
299 return 1;
300}
301
302static bool reloc_root_is_dead(struct btrfs_root *root)
303{
304 /*
305 * Pair with set_bit/clear_bit in clean_dirty_subvols and
306 * btrfs_update_reloc_root. We need to see the updated bit before
307 * trying to access reloc_root
308 */
309 smp_rmb();
310 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
311 return true;
312 return false;
313}
314
315/*
316 * Check if this subvolume tree has valid reloc tree.
317 *
318 * Reloc tree after swap is considered dead, thus not considered as valid.
319 * This is enough for most callers, as they don't distinguish dead reloc root
320 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
321 * special case.
322 */
323static bool have_reloc_root(struct btrfs_root *root)
324{
325 if (reloc_root_is_dead(root))
326 return false;
327 if (!root->reloc_root)
328 return false;
329 return true;
330}
331
332int btrfs_should_ignore_reloc_root(struct btrfs_root *root)
333{
334 struct btrfs_root *reloc_root;
335
336 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
337 return 0;
338
339 /* This root has been merged with its reloc tree, we can ignore it */
340 if (reloc_root_is_dead(root))
341 return 1;
342
343 reloc_root = root->reloc_root;
344 if (!reloc_root)
345 return 0;
346
347 if (btrfs_header_generation(reloc_root->commit_root) ==
348 root->fs_info->running_transaction->transid)
349 return 0;
350 /*
351 * if there is reloc tree and it was created in previous
352 * transaction backref lookup can find the reloc tree,
353 * so backref node for the fs tree root is useless for
354 * relocation.
355 */
356 return 1;
357}
358
359/*
360 * find reloc tree by address of tree root
361 */
362struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
363{
364 struct reloc_control *rc = fs_info->reloc_ctl;
365 struct rb_node *rb_node;
366 struct mapping_node *node;
367 struct btrfs_root *root = NULL;
368
369 ASSERT(rc);
370 spin_lock(&rc->reloc_root_tree.lock);
371 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
372 if (rb_node) {
373 node = rb_entry(rb_node, struct mapping_node, rb_node);
374 root = node->data;
375 }
376 spin_unlock(&rc->reloc_root_tree.lock);
377 return btrfs_grab_root(root);
378}
379
380/*
381 * For useless nodes, do two major clean ups:
382 *
383 * - Cleanup the children edges and nodes
384 * If child node is also orphan (no parent) during cleanup, then the child
385 * node will also be cleaned up.
386 *
387 * - Freeing up leaves (level 0), keeps nodes detached
388 * For nodes, the node is still cached as "detached"
389 *
390 * Return false if @node is not in the @useless_nodes list.
391 * Return true if @node is in the @useless_nodes list.
392 */
393static bool handle_useless_nodes(struct reloc_control *rc,
394 struct btrfs_backref_node *node)
395{
396 struct btrfs_backref_cache *cache = &rc->backref_cache;
397 struct list_head *useless_node = &cache->useless_node;
398 bool ret = false;
399
400 while (!list_empty(useless_node)) {
401 struct btrfs_backref_node *cur;
402
403 cur = list_first_entry(useless_node, struct btrfs_backref_node,
404 list);
405 list_del_init(&cur->list);
406
407 /* Only tree root nodes can be added to @useless_nodes */
408 ASSERT(list_empty(&cur->upper));
409
410 if (cur == node)
411 ret = true;
412
413 /* The node is the lowest node */
414 if (cur->lowest) {
415 list_del_init(&cur->lower);
416 cur->lowest = 0;
417 }
418
419 /* Cleanup the lower edges */
420 while (!list_empty(&cur->lower)) {
421 struct btrfs_backref_edge *edge;
422 struct btrfs_backref_node *lower;
423
424 edge = list_entry(cur->lower.next,
425 struct btrfs_backref_edge, list[UPPER]);
426 list_del(&edge->list[UPPER]);
427 list_del(&edge->list[LOWER]);
428 lower = edge->node[LOWER];
429 btrfs_backref_free_edge(cache, edge);
430
431 /* Child node is also orphan, queue for cleanup */
432 if (list_empty(&lower->upper))
433 list_add(&lower->list, useless_node);
434 }
435 /* Mark this block processed for relocation */
436 mark_block_processed(rc, cur);
437
438 /*
439 * Backref nodes for tree leaves are deleted from the cache.
440 * Backref nodes for upper level tree blocks are left in the
441 * cache to avoid unnecessary backref lookup.
442 */
443 if (cur->level > 0) {
444 list_add(&cur->list, &cache->detached);
445 cur->detached = 1;
446 } else {
447 rb_erase(&cur->rb_node, &cache->rb_root);
448 btrfs_backref_free_node(cache, cur);
449 }
450 }
451 return ret;
452}
453
454/*
455 * Build backref tree for a given tree block. Root of the backref tree
456 * corresponds the tree block, leaves of the backref tree correspond roots of
457 * b-trees that reference the tree block.
458 *
459 * The basic idea of this function is check backrefs of a given block to find
460 * upper level blocks that reference the block, and then check backrefs of
461 * these upper level blocks recursively. The recursion stops when tree root is
462 * reached or backrefs for the block is cached.
463 *
464 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
465 * all upper level blocks that directly/indirectly reference the block are also
466 * cached.
467 */
468static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
469 struct reloc_control *rc, struct btrfs_key *node_key,
470 int level, u64 bytenr)
471{
472 struct btrfs_backref_iter *iter;
473 struct btrfs_backref_cache *cache = &rc->backref_cache;
474 /* For searching parent of TREE_BLOCK_REF */
475 struct btrfs_path *path;
476 struct btrfs_backref_node *cur;
477 struct btrfs_backref_node *node = NULL;
478 struct btrfs_backref_edge *edge;
479 int ret;
480 int err = 0;
481
482 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info);
483 if (!iter)
484 return ERR_PTR(-ENOMEM);
485 path = btrfs_alloc_path();
486 if (!path) {
487 err = -ENOMEM;
488 goto out;
489 }
490
491 node = btrfs_backref_alloc_node(cache, bytenr, level);
492 if (!node) {
493 err = -ENOMEM;
494 goto out;
495 }
496
497 node->lowest = 1;
498 cur = node;
499
500 /* Breadth-first search to build backref cache */
501 do {
502 ret = btrfs_backref_add_tree_node(cache, path, iter, node_key,
503 cur);
504 if (ret < 0) {
505 err = ret;
506 goto out;
507 }
508 edge = list_first_entry_or_null(&cache->pending_edge,
509 struct btrfs_backref_edge, list[UPPER]);
510 /*
511 * The pending list isn't empty, take the first block to
512 * process
513 */
514 if (edge) {
515 list_del_init(&edge->list[UPPER]);
516 cur = edge->node[UPPER];
517 }
518 } while (edge);
519
520 /* Finish the upper linkage of newly added edges/nodes */
521 ret = btrfs_backref_finish_upper_links(cache, node);
522 if (ret < 0) {
523 err = ret;
524 goto out;
525 }
526
527 if (handle_useless_nodes(rc, node))
528 node = NULL;
529out:
530 btrfs_backref_iter_free(iter);
531 btrfs_free_path(path);
532 if (err) {
533 btrfs_backref_error_cleanup(cache, node);
534 return ERR_PTR(err);
535 }
536 ASSERT(!node || !node->detached);
537 ASSERT(list_empty(&cache->useless_node) &&
538 list_empty(&cache->pending_edge));
539 return node;
540}
541
542/*
543 * helper to add backref node for the newly created snapshot.
544 * the backref node is created by cloning backref node that
545 * corresponds to root of source tree
546 */
547static int clone_backref_node(struct btrfs_trans_handle *trans,
548 struct reloc_control *rc,
549 struct btrfs_root *src,
550 struct btrfs_root *dest)
551{
552 struct btrfs_root *reloc_root = src->reloc_root;
553 struct btrfs_backref_cache *cache = &rc->backref_cache;
554 struct btrfs_backref_node *node = NULL;
555 struct btrfs_backref_node *new_node;
556 struct btrfs_backref_edge *edge;
557 struct btrfs_backref_edge *new_edge;
558 struct rb_node *rb_node;
559
560 if (cache->last_trans > 0)
561 update_backref_cache(trans, cache);
562
563 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
564 if (rb_node) {
565 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
566 if (node->detached)
567 node = NULL;
568 else
569 BUG_ON(node->new_bytenr != reloc_root->node->start);
570 }
571
572 if (!node) {
573 rb_node = rb_simple_search(&cache->rb_root,
574 reloc_root->commit_root->start);
575 if (rb_node) {
576 node = rb_entry(rb_node, struct btrfs_backref_node,
577 rb_node);
578 BUG_ON(node->detached);
579 }
580 }
581
582 if (!node)
583 return 0;
584
585 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
586 node->level);
587 if (!new_node)
588 return -ENOMEM;
589
590 new_node->lowest = node->lowest;
591 new_node->checked = 1;
592 new_node->root = btrfs_grab_root(dest);
593 ASSERT(new_node->root);
594
595 if (!node->lowest) {
596 list_for_each_entry(edge, &node->lower, list[UPPER]) {
597 new_edge = btrfs_backref_alloc_edge(cache);
598 if (!new_edge)
599 goto fail;
600
601 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
602 new_node, LINK_UPPER);
603 }
604 } else {
605 list_add_tail(&new_node->lower, &cache->leaves);
606 }
607
608 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
609 &new_node->rb_node);
610 if (rb_node)
611 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
612
613 if (!new_node->lowest) {
614 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
615 list_add_tail(&new_edge->list[LOWER],
616 &new_edge->node[LOWER]->upper);
617 }
618 }
619 return 0;
620fail:
621 while (!list_empty(&new_node->lower)) {
622 new_edge = list_entry(new_node->lower.next,
623 struct btrfs_backref_edge, list[UPPER]);
624 list_del(&new_edge->list[UPPER]);
625 btrfs_backref_free_edge(cache, new_edge);
626 }
627 btrfs_backref_free_node(cache, new_node);
628 return -ENOMEM;
629}
630
631/*
632 * helper to add 'address of tree root -> reloc tree' mapping
633 */
634static int __must_check __add_reloc_root(struct btrfs_root *root)
635{
636 struct btrfs_fs_info *fs_info = root->fs_info;
637 struct rb_node *rb_node;
638 struct mapping_node *node;
639 struct reloc_control *rc = fs_info->reloc_ctl;
640
641 node = kmalloc(sizeof(*node), GFP_NOFS);
642 if (!node)
643 return -ENOMEM;
644
645 node->bytenr = root->commit_root->start;
646 node->data = root;
647
648 spin_lock(&rc->reloc_root_tree.lock);
649 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
650 node->bytenr, &node->rb_node);
651 spin_unlock(&rc->reloc_root_tree.lock);
652 if (rb_node) {
653 btrfs_err(fs_info,
654 "Duplicate root found for start=%llu while inserting into relocation tree",
655 node->bytenr);
656 return -EEXIST;
657 }
658
659 list_add_tail(&root->root_list, &rc->reloc_roots);
660 return 0;
661}
662
663/*
664 * helper to delete the 'address of tree root -> reloc tree'
665 * mapping
666 */
667static void __del_reloc_root(struct btrfs_root *root)
668{
669 struct btrfs_fs_info *fs_info = root->fs_info;
670 struct rb_node *rb_node;
671 struct mapping_node *node = NULL;
672 struct reloc_control *rc = fs_info->reloc_ctl;
673 bool put_ref = false;
674
675 if (rc && root->node) {
676 spin_lock(&rc->reloc_root_tree.lock);
677 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
678 root->commit_root->start);
679 if (rb_node) {
680 node = rb_entry(rb_node, struct mapping_node, rb_node);
681 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
682 RB_CLEAR_NODE(&node->rb_node);
683 }
684 spin_unlock(&rc->reloc_root_tree.lock);
685 ASSERT(!node || (struct btrfs_root *)node->data == root);
686 }
687
688 /*
689 * We only put the reloc root here if it's on the list. There's a lot
690 * of places where the pattern is to splice the rc->reloc_roots, process
691 * the reloc roots, and then add the reloc root back onto
692 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
693 * list we don't want the reference being dropped, because the guy
694 * messing with the list is in charge of the reference.
695 */
696 spin_lock(&fs_info->trans_lock);
697 if (!list_empty(&root->root_list)) {
698 put_ref = true;
699 list_del_init(&root->root_list);
700 }
701 spin_unlock(&fs_info->trans_lock);
702 if (put_ref)
703 btrfs_put_root(root);
704 kfree(node);
705}
706
707/*
708 * helper to update the 'address of tree root -> reloc tree'
709 * mapping
710 */
711static int __update_reloc_root(struct btrfs_root *root)
712{
713 struct btrfs_fs_info *fs_info = root->fs_info;
714 struct rb_node *rb_node;
715 struct mapping_node *node = NULL;
716 struct reloc_control *rc = fs_info->reloc_ctl;
717
718 spin_lock(&rc->reloc_root_tree.lock);
719 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
720 root->commit_root->start);
721 if (rb_node) {
722 node = rb_entry(rb_node, struct mapping_node, rb_node);
723 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
724 }
725 spin_unlock(&rc->reloc_root_tree.lock);
726
727 if (!node)
728 return 0;
729 BUG_ON((struct btrfs_root *)node->data != root);
730
731 spin_lock(&rc->reloc_root_tree.lock);
732 node->bytenr = root->node->start;
733 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
734 node->bytenr, &node->rb_node);
735 spin_unlock(&rc->reloc_root_tree.lock);
736 if (rb_node)
737 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
738 return 0;
739}
740
741static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
742 struct btrfs_root *root, u64 objectid)
743{
744 struct btrfs_fs_info *fs_info = root->fs_info;
745 struct btrfs_root *reloc_root;
746 struct extent_buffer *eb;
747 struct btrfs_root_item *root_item;
748 struct btrfs_key root_key;
749 int ret = 0;
750 bool must_abort = false;
751
752 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
753 if (!root_item)
754 return ERR_PTR(-ENOMEM);
755
756 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
757 root_key.type = BTRFS_ROOT_ITEM_KEY;
758 root_key.offset = objectid;
759
760 if (root->root_key.objectid == objectid) {
761 u64 commit_root_gen;
762
763 /* called by btrfs_init_reloc_root */
764 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
765 BTRFS_TREE_RELOC_OBJECTID);
766 if (ret)
767 goto fail;
768
769 /*
770 * Set the last_snapshot field to the generation of the commit
771 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
772 * correctly (returns true) when the relocation root is created
773 * either inside the critical section of a transaction commit
774 * (through transaction.c:qgroup_account_snapshot()) and when
775 * it's created before the transaction commit is started.
776 */
777 commit_root_gen = btrfs_header_generation(root->commit_root);
778 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
779 } else {
780 /*
781 * called by btrfs_reloc_post_snapshot_hook.
782 * the source tree is a reloc tree, all tree blocks
783 * modified after it was created have RELOC flag
784 * set in their headers. so it's OK to not update
785 * the 'last_snapshot'.
786 */
787 ret = btrfs_copy_root(trans, root, root->node, &eb,
788 BTRFS_TREE_RELOC_OBJECTID);
789 if (ret)
790 goto fail;
791 }
792
793 /*
794 * We have changed references at this point, we must abort the
795 * transaction if anything fails.
796 */
797 must_abort = true;
798
799 memcpy(root_item, &root->root_item, sizeof(*root_item));
800 btrfs_set_root_bytenr(root_item, eb->start);
801 btrfs_set_root_level(root_item, btrfs_header_level(eb));
802 btrfs_set_root_generation(root_item, trans->transid);
803
804 if (root->root_key.objectid == objectid) {
805 btrfs_set_root_refs(root_item, 0);
806 memset(&root_item->drop_progress, 0,
807 sizeof(struct btrfs_disk_key));
808 btrfs_set_root_drop_level(root_item, 0);
809 }
810
811 btrfs_tree_unlock(eb);
812 free_extent_buffer(eb);
813
814 ret = btrfs_insert_root(trans, fs_info->tree_root,
815 &root_key, root_item);
816 if (ret)
817 goto fail;
818
819 kfree(root_item);
820
821 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
822 if (IS_ERR(reloc_root)) {
823 ret = PTR_ERR(reloc_root);
824 goto abort;
825 }
826 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
827 reloc_root->last_trans = trans->transid;
828 return reloc_root;
829fail:
830 kfree(root_item);
831abort:
832 if (must_abort)
833 btrfs_abort_transaction(trans, ret);
834 return ERR_PTR(ret);
835}
836
837/*
838 * create reloc tree for a given fs tree. reloc tree is just a
839 * snapshot of the fs tree with special root objectid.
840 *
841 * The reloc_root comes out of here with two references, one for
842 * root->reloc_root, and another for being on the rc->reloc_roots list.
843 */
844int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
845 struct btrfs_root *root)
846{
847 struct btrfs_fs_info *fs_info = root->fs_info;
848 struct btrfs_root *reloc_root;
849 struct reloc_control *rc = fs_info->reloc_ctl;
850 struct btrfs_block_rsv *rsv;
851 int clear_rsv = 0;
852 int ret;
853
854 if (!rc)
855 return 0;
856
857 /*
858 * The subvolume has reloc tree but the swap is finished, no need to
859 * create/update the dead reloc tree
860 */
861 if (reloc_root_is_dead(root))
862 return 0;
863
864 /*
865 * This is subtle but important. We do not do
866 * record_root_in_transaction for reloc roots, instead we record their
867 * corresponding fs root, and then here we update the last trans for the
868 * reloc root. This means that we have to do this for the entire life
869 * of the reloc root, regardless of which stage of the relocation we are
870 * in.
871 */
872 if (root->reloc_root) {
873 reloc_root = root->reloc_root;
874 reloc_root->last_trans = trans->transid;
875 return 0;
876 }
877
878 /*
879 * We are merging reloc roots, we do not need new reloc trees. Also
880 * reloc trees never need their own reloc tree.
881 */
882 if (!rc->create_reloc_tree ||
883 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
884 return 0;
885
886 if (!trans->reloc_reserved) {
887 rsv = trans->block_rsv;
888 trans->block_rsv = rc->block_rsv;
889 clear_rsv = 1;
890 }
891 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
892 if (clear_rsv)
893 trans->block_rsv = rsv;
894 if (IS_ERR(reloc_root))
895 return PTR_ERR(reloc_root);
896
897 ret = __add_reloc_root(reloc_root);
898 ASSERT(ret != -EEXIST);
899 if (ret) {
900 /* Pairs with create_reloc_root */
901 btrfs_put_root(reloc_root);
902 return ret;
903 }
904 root->reloc_root = btrfs_grab_root(reloc_root);
905 return 0;
906}
907
908/*
909 * update root item of reloc tree
910 */
911int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
912 struct btrfs_root *root)
913{
914 struct btrfs_fs_info *fs_info = root->fs_info;
915 struct btrfs_root *reloc_root;
916 struct btrfs_root_item *root_item;
917 int ret;
918
919 if (!have_reloc_root(root))
920 return 0;
921
922 reloc_root = root->reloc_root;
923 root_item = &reloc_root->root_item;
924
925 /*
926 * We are probably ok here, but __del_reloc_root() will drop its ref of
927 * the root. We have the ref for root->reloc_root, but just in case
928 * hold it while we update the reloc root.
929 */
930 btrfs_grab_root(reloc_root);
931
932 /* root->reloc_root will stay until current relocation finished */
933 if (fs_info->reloc_ctl->merge_reloc_tree &&
934 btrfs_root_refs(root_item) == 0) {
935 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
936 /*
937 * Mark the tree as dead before we change reloc_root so
938 * have_reloc_root will not touch it from now on.
939 */
940 smp_wmb();
941 __del_reloc_root(reloc_root);
942 }
943
944 if (reloc_root->commit_root != reloc_root->node) {
945 __update_reloc_root(reloc_root);
946 btrfs_set_root_node(root_item, reloc_root->node);
947 free_extent_buffer(reloc_root->commit_root);
948 reloc_root->commit_root = btrfs_root_node(reloc_root);
949 }
950
951 ret = btrfs_update_root(trans, fs_info->tree_root,
952 &reloc_root->root_key, root_item);
953 btrfs_put_root(reloc_root);
954 return ret;
955}
956
957/*
958 * helper to find first cached inode with inode number >= objectid
959 * in a subvolume
960 */
961static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
962{
963 struct rb_node *node;
964 struct rb_node *prev;
965 struct btrfs_inode *entry;
966 struct inode *inode;
967
968 spin_lock(&root->inode_lock);
969again:
970 node = root->inode_tree.rb_node;
971 prev = NULL;
972 while (node) {
973 prev = node;
974 entry = rb_entry(node, struct btrfs_inode, rb_node);
975
976 if (objectid < btrfs_ino(entry))
977 node = node->rb_left;
978 else if (objectid > btrfs_ino(entry))
979 node = node->rb_right;
980 else
981 break;
982 }
983 if (!node) {
984 while (prev) {
985 entry = rb_entry(prev, struct btrfs_inode, rb_node);
986 if (objectid <= btrfs_ino(entry)) {
987 node = prev;
988 break;
989 }
990 prev = rb_next(prev);
991 }
992 }
993 while (node) {
994 entry = rb_entry(node, struct btrfs_inode, rb_node);
995 inode = igrab(&entry->vfs_inode);
996 if (inode) {
997 spin_unlock(&root->inode_lock);
998 return inode;
999 }
1000
1001 objectid = btrfs_ino(entry) + 1;
1002 if (cond_resched_lock(&root->inode_lock))
1003 goto again;
1004
1005 node = rb_next(node);
1006 }
1007 spin_unlock(&root->inode_lock);
1008 return NULL;
1009}
1010
1011/*
1012 * get new location of data
1013 */
1014static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1015 u64 bytenr, u64 num_bytes)
1016{
1017 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1018 struct btrfs_path *path;
1019 struct btrfs_file_extent_item *fi;
1020 struct extent_buffer *leaf;
1021 int ret;
1022
1023 path = btrfs_alloc_path();
1024 if (!path)
1025 return -ENOMEM;
1026
1027 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1028 ret = btrfs_lookup_file_extent(NULL, root, path,
1029 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1030 if (ret < 0)
1031 goto out;
1032 if (ret > 0) {
1033 ret = -ENOENT;
1034 goto out;
1035 }
1036
1037 leaf = path->nodes[0];
1038 fi = btrfs_item_ptr(leaf, path->slots[0],
1039 struct btrfs_file_extent_item);
1040
1041 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1042 btrfs_file_extent_compression(leaf, fi) ||
1043 btrfs_file_extent_encryption(leaf, fi) ||
1044 btrfs_file_extent_other_encoding(leaf, fi));
1045
1046 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1047 ret = -EINVAL;
1048 goto out;
1049 }
1050
1051 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1052 ret = 0;
1053out:
1054 btrfs_free_path(path);
1055 return ret;
1056}
1057
1058/*
1059 * update file extent items in the tree leaf to point to
1060 * the new locations.
1061 */
1062static noinline_for_stack
1063int replace_file_extents(struct btrfs_trans_handle *trans,
1064 struct reloc_control *rc,
1065 struct btrfs_root *root,
1066 struct extent_buffer *leaf)
1067{
1068 struct btrfs_fs_info *fs_info = root->fs_info;
1069 struct btrfs_key key;
1070 struct btrfs_file_extent_item *fi;
1071 struct inode *inode = NULL;
1072 u64 parent;
1073 u64 bytenr;
1074 u64 new_bytenr = 0;
1075 u64 num_bytes;
1076 u64 end;
1077 u32 nritems;
1078 u32 i;
1079 int ret = 0;
1080 int first = 1;
1081 int dirty = 0;
1082
1083 if (rc->stage != UPDATE_DATA_PTRS)
1084 return 0;
1085
1086 /* reloc trees always use full backref */
1087 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1088 parent = leaf->start;
1089 else
1090 parent = 0;
1091
1092 nritems = btrfs_header_nritems(leaf);
1093 for (i = 0; i < nritems; i++) {
1094 struct btrfs_ref ref = { 0 };
1095
1096 cond_resched();
1097 btrfs_item_key_to_cpu(leaf, &key, i);
1098 if (key.type != BTRFS_EXTENT_DATA_KEY)
1099 continue;
1100 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1101 if (btrfs_file_extent_type(leaf, fi) ==
1102 BTRFS_FILE_EXTENT_INLINE)
1103 continue;
1104 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1105 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1106 if (bytenr == 0)
1107 continue;
1108 if (!in_range(bytenr, rc->block_group->start,
1109 rc->block_group->length))
1110 continue;
1111
1112 /*
1113 * if we are modifying block in fs tree, wait for read_folio
1114 * to complete and drop the extent cache
1115 */
1116 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1117 if (first) {
1118 inode = find_next_inode(root, key.objectid);
1119 first = 0;
1120 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1121 btrfs_add_delayed_iput(BTRFS_I(inode));
1122 inode = find_next_inode(root, key.objectid);
1123 }
1124 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1125 struct extent_state *cached_state = NULL;
1126
1127 end = key.offset +
1128 btrfs_file_extent_num_bytes(leaf, fi);
1129 WARN_ON(!IS_ALIGNED(key.offset,
1130 fs_info->sectorsize));
1131 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1132 end--;
1133 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1134 key.offset, end,
1135 &cached_state);
1136 if (!ret)
1137 continue;
1138
1139 btrfs_drop_extent_map_range(BTRFS_I(inode),
1140 key.offset, end, true);
1141 unlock_extent(&BTRFS_I(inode)->io_tree,
1142 key.offset, end, &cached_state);
1143 }
1144 }
1145
1146 ret = get_new_location(rc->data_inode, &new_bytenr,
1147 bytenr, num_bytes);
1148 if (ret) {
1149 /*
1150 * Don't have to abort since we've not changed anything
1151 * in the file extent yet.
1152 */
1153 break;
1154 }
1155
1156 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1157 dirty = 1;
1158
1159 key.offset -= btrfs_file_extent_offset(leaf, fi);
1160 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1161 num_bytes, parent);
1162 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1163 key.objectid, key.offset,
1164 root->root_key.objectid, false);
1165 ret = btrfs_inc_extent_ref(trans, &ref);
1166 if (ret) {
1167 btrfs_abort_transaction(trans, ret);
1168 break;
1169 }
1170
1171 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1172 num_bytes, parent);
1173 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1174 key.objectid, key.offset,
1175 root->root_key.objectid, false);
1176 ret = btrfs_free_extent(trans, &ref);
1177 if (ret) {
1178 btrfs_abort_transaction(trans, ret);
1179 break;
1180 }
1181 }
1182 if (dirty)
1183 btrfs_mark_buffer_dirty(leaf);
1184 if (inode)
1185 btrfs_add_delayed_iput(BTRFS_I(inode));
1186 return ret;
1187}
1188
1189static noinline_for_stack
1190int memcmp_node_keys(struct extent_buffer *eb, int slot,
1191 struct btrfs_path *path, int level)
1192{
1193 struct btrfs_disk_key key1;
1194 struct btrfs_disk_key key2;
1195 btrfs_node_key(eb, &key1, slot);
1196 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1197 return memcmp(&key1, &key2, sizeof(key1));
1198}
1199
1200/*
1201 * try to replace tree blocks in fs tree with the new blocks
1202 * in reloc tree. tree blocks haven't been modified since the
1203 * reloc tree was create can be replaced.
1204 *
1205 * if a block was replaced, level of the block + 1 is returned.
1206 * if no block got replaced, 0 is returned. if there are other
1207 * errors, a negative error number is returned.
1208 */
1209static noinline_for_stack
1210int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1211 struct btrfs_root *dest, struct btrfs_root *src,
1212 struct btrfs_path *path, struct btrfs_key *next_key,
1213 int lowest_level, int max_level)
1214{
1215 struct btrfs_fs_info *fs_info = dest->fs_info;
1216 struct extent_buffer *eb;
1217 struct extent_buffer *parent;
1218 struct btrfs_ref ref = { 0 };
1219 struct btrfs_key key;
1220 u64 old_bytenr;
1221 u64 new_bytenr;
1222 u64 old_ptr_gen;
1223 u64 new_ptr_gen;
1224 u64 last_snapshot;
1225 u32 blocksize;
1226 int cow = 0;
1227 int level;
1228 int ret;
1229 int slot;
1230
1231 ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1232 ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1233
1234 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1235again:
1236 slot = path->slots[lowest_level];
1237 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1238
1239 eb = btrfs_lock_root_node(dest);
1240 level = btrfs_header_level(eb);
1241
1242 if (level < lowest_level) {
1243 btrfs_tree_unlock(eb);
1244 free_extent_buffer(eb);
1245 return 0;
1246 }
1247
1248 if (cow) {
1249 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1250 BTRFS_NESTING_COW);
1251 if (ret) {
1252 btrfs_tree_unlock(eb);
1253 free_extent_buffer(eb);
1254 return ret;
1255 }
1256 }
1257
1258 if (next_key) {
1259 next_key->objectid = (u64)-1;
1260 next_key->type = (u8)-1;
1261 next_key->offset = (u64)-1;
1262 }
1263
1264 parent = eb;
1265 while (1) {
1266 level = btrfs_header_level(parent);
1267 ASSERT(level >= lowest_level);
1268
1269 ret = btrfs_bin_search(parent, &key, &slot);
1270 if (ret < 0)
1271 break;
1272 if (ret && slot > 0)
1273 slot--;
1274
1275 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1276 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1277
1278 old_bytenr = btrfs_node_blockptr(parent, slot);
1279 blocksize = fs_info->nodesize;
1280 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1281
1282 if (level <= max_level) {
1283 eb = path->nodes[level];
1284 new_bytenr = btrfs_node_blockptr(eb,
1285 path->slots[level]);
1286 new_ptr_gen = btrfs_node_ptr_generation(eb,
1287 path->slots[level]);
1288 } else {
1289 new_bytenr = 0;
1290 new_ptr_gen = 0;
1291 }
1292
1293 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1294 ret = level;
1295 break;
1296 }
1297
1298 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1299 memcmp_node_keys(parent, slot, path, level)) {
1300 if (level <= lowest_level) {
1301 ret = 0;
1302 break;
1303 }
1304
1305 eb = btrfs_read_node_slot(parent, slot);
1306 if (IS_ERR(eb)) {
1307 ret = PTR_ERR(eb);
1308 break;
1309 }
1310 btrfs_tree_lock(eb);
1311 if (cow) {
1312 ret = btrfs_cow_block(trans, dest, eb, parent,
1313 slot, &eb,
1314 BTRFS_NESTING_COW);
1315 if (ret) {
1316 btrfs_tree_unlock(eb);
1317 free_extent_buffer(eb);
1318 break;
1319 }
1320 }
1321
1322 btrfs_tree_unlock(parent);
1323 free_extent_buffer(parent);
1324
1325 parent = eb;
1326 continue;
1327 }
1328
1329 if (!cow) {
1330 btrfs_tree_unlock(parent);
1331 free_extent_buffer(parent);
1332 cow = 1;
1333 goto again;
1334 }
1335
1336 btrfs_node_key_to_cpu(path->nodes[level], &key,
1337 path->slots[level]);
1338 btrfs_release_path(path);
1339
1340 path->lowest_level = level;
1341 set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1342 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1343 clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1344 path->lowest_level = 0;
1345 if (ret) {
1346 if (ret > 0)
1347 ret = -ENOENT;
1348 break;
1349 }
1350
1351 /*
1352 * Info qgroup to trace both subtrees.
1353 *
1354 * We must trace both trees.
1355 * 1) Tree reloc subtree
1356 * If not traced, we will leak data numbers
1357 * 2) Fs subtree
1358 * If not traced, we will double count old data
1359 *
1360 * We don't scan the subtree right now, but only record
1361 * the swapped tree blocks.
1362 * The real subtree rescan is delayed until we have new
1363 * CoW on the subtree root node before transaction commit.
1364 */
1365 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1366 rc->block_group, parent, slot,
1367 path->nodes[level], path->slots[level],
1368 last_snapshot);
1369 if (ret < 0)
1370 break;
1371 /*
1372 * swap blocks in fs tree and reloc tree.
1373 */
1374 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1375 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1376 btrfs_mark_buffer_dirty(parent);
1377
1378 btrfs_set_node_blockptr(path->nodes[level],
1379 path->slots[level], old_bytenr);
1380 btrfs_set_node_ptr_generation(path->nodes[level],
1381 path->slots[level], old_ptr_gen);
1382 btrfs_mark_buffer_dirty(path->nodes[level]);
1383
1384 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1385 blocksize, path->nodes[level]->start);
1386 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1387 0, true);
1388 ret = btrfs_inc_extent_ref(trans, &ref);
1389 if (ret) {
1390 btrfs_abort_transaction(trans, ret);
1391 break;
1392 }
1393 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1394 blocksize, 0);
1395 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0,
1396 true);
1397 ret = btrfs_inc_extent_ref(trans, &ref);
1398 if (ret) {
1399 btrfs_abort_transaction(trans, ret);
1400 break;
1401 }
1402
1403 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1404 blocksize, path->nodes[level]->start);
1405 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1406 0, true);
1407 ret = btrfs_free_extent(trans, &ref);
1408 if (ret) {
1409 btrfs_abort_transaction(trans, ret);
1410 break;
1411 }
1412
1413 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1414 blocksize, 0);
1415 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid,
1416 0, true);
1417 ret = btrfs_free_extent(trans, &ref);
1418 if (ret) {
1419 btrfs_abort_transaction(trans, ret);
1420 break;
1421 }
1422
1423 btrfs_unlock_up_safe(path, 0);
1424
1425 ret = level;
1426 break;
1427 }
1428 btrfs_tree_unlock(parent);
1429 free_extent_buffer(parent);
1430 return ret;
1431}
1432
1433/*
1434 * helper to find next relocated block in reloc tree
1435 */
1436static noinline_for_stack
1437int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1438 int *level)
1439{
1440 struct extent_buffer *eb;
1441 int i;
1442 u64 last_snapshot;
1443 u32 nritems;
1444
1445 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1446
1447 for (i = 0; i < *level; i++) {
1448 free_extent_buffer(path->nodes[i]);
1449 path->nodes[i] = NULL;
1450 }
1451
1452 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1453 eb = path->nodes[i];
1454 nritems = btrfs_header_nritems(eb);
1455 while (path->slots[i] + 1 < nritems) {
1456 path->slots[i]++;
1457 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1458 last_snapshot)
1459 continue;
1460
1461 *level = i;
1462 return 0;
1463 }
1464 free_extent_buffer(path->nodes[i]);
1465 path->nodes[i] = NULL;
1466 }
1467 return 1;
1468}
1469
1470/*
1471 * walk down reloc tree to find relocated block of lowest level
1472 */
1473static noinline_for_stack
1474int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1475 int *level)
1476{
1477 struct extent_buffer *eb = NULL;
1478 int i;
1479 u64 ptr_gen = 0;
1480 u64 last_snapshot;
1481 u32 nritems;
1482
1483 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1484
1485 for (i = *level; i > 0; i--) {
1486 eb = path->nodes[i];
1487 nritems = btrfs_header_nritems(eb);
1488 while (path->slots[i] < nritems) {
1489 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1490 if (ptr_gen > last_snapshot)
1491 break;
1492 path->slots[i]++;
1493 }
1494 if (path->slots[i] >= nritems) {
1495 if (i == *level)
1496 break;
1497 *level = i + 1;
1498 return 0;
1499 }
1500 if (i == 1) {
1501 *level = i;
1502 return 0;
1503 }
1504
1505 eb = btrfs_read_node_slot(eb, path->slots[i]);
1506 if (IS_ERR(eb))
1507 return PTR_ERR(eb);
1508 BUG_ON(btrfs_header_level(eb) != i - 1);
1509 path->nodes[i - 1] = eb;
1510 path->slots[i - 1] = 0;
1511 }
1512 return 1;
1513}
1514
1515/*
1516 * invalidate extent cache for file extents whose key in range of
1517 * [min_key, max_key)
1518 */
1519static int invalidate_extent_cache(struct btrfs_root *root,
1520 struct btrfs_key *min_key,
1521 struct btrfs_key *max_key)
1522{
1523 struct btrfs_fs_info *fs_info = root->fs_info;
1524 struct inode *inode = NULL;
1525 u64 objectid;
1526 u64 start, end;
1527 u64 ino;
1528
1529 objectid = min_key->objectid;
1530 while (1) {
1531 struct extent_state *cached_state = NULL;
1532
1533 cond_resched();
1534 iput(inode);
1535
1536 if (objectid > max_key->objectid)
1537 break;
1538
1539 inode = find_next_inode(root, objectid);
1540 if (!inode)
1541 break;
1542 ino = btrfs_ino(BTRFS_I(inode));
1543
1544 if (ino > max_key->objectid) {
1545 iput(inode);
1546 break;
1547 }
1548
1549 objectid = ino + 1;
1550 if (!S_ISREG(inode->i_mode))
1551 continue;
1552
1553 if (unlikely(min_key->objectid == ino)) {
1554 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1555 continue;
1556 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1557 start = 0;
1558 else {
1559 start = min_key->offset;
1560 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1561 }
1562 } else {
1563 start = 0;
1564 }
1565
1566 if (unlikely(max_key->objectid == ino)) {
1567 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1568 continue;
1569 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1570 end = (u64)-1;
1571 } else {
1572 if (max_key->offset == 0)
1573 continue;
1574 end = max_key->offset;
1575 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1576 end--;
1577 }
1578 } else {
1579 end = (u64)-1;
1580 }
1581
1582 /* the lock_extent waits for read_folio to complete */
1583 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1584 btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true);
1585 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1586 }
1587 return 0;
1588}
1589
1590static int find_next_key(struct btrfs_path *path, int level,
1591 struct btrfs_key *key)
1592
1593{
1594 while (level < BTRFS_MAX_LEVEL) {
1595 if (!path->nodes[level])
1596 break;
1597 if (path->slots[level] + 1 <
1598 btrfs_header_nritems(path->nodes[level])) {
1599 btrfs_node_key_to_cpu(path->nodes[level], key,
1600 path->slots[level] + 1);
1601 return 0;
1602 }
1603 level++;
1604 }
1605 return 1;
1606}
1607
1608/*
1609 * Insert current subvolume into reloc_control::dirty_subvol_roots
1610 */
1611static int insert_dirty_subvol(struct btrfs_trans_handle *trans,
1612 struct reloc_control *rc,
1613 struct btrfs_root *root)
1614{
1615 struct btrfs_root *reloc_root = root->reloc_root;
1616 struct btrfs_root_item *reloc_root_item;
1617 int ret;
1618
1619 /* @root must be a subvolume tree root with a valid reloc tree */
1620 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1621 ASSERT(reloc_root);
1622
1623 reloc_root_item = &reloc_root->root_item;
1624 memset(&reloc_root_item->drop_progress, 0,
1625 sizeof(reloc_root_item->drop_progress));
1626 btrfs_set_root_drop_level(reloc_root_item, 0);
1627 btrfs_set_root_refs(reloc_root_item, 0);
1628 ret = btrfs_update_reloc_root(trans, root);
1629 if (ret)
1630 return ret;
1631
1632 if (list_empty(&root->reloc_dirty_list)) {
1633 btrfs_grab_root(root);
1634 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1635 }
1636
1637 return 0;
1638}
1639
1640static int clean_dirty_subvols(struct reloc_control *rc)
1641{
1642 struct btrfs_root *root;
1643 struct btrfs_root *next;
1644 int ret = 0;
1645 int ret2;
1646
1647 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1648 reloc_dirty_list) {
1649 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1650 /* Merged subvolume, cleanup its reloc root */
1651 struct btrfs_root *reloc_root = root->reloc_root;
1652
1653 list_del_init(&root->reloc_dirty_list);
1654 root->reloc_root = NULL;
1655 /*
1656 * Need barrier to ensure clear_bit() only happens after
1657 * root->reloc_root = NULL. Pairs with have_reloc_root.
1658 */
1659 smp_wmb();
1660 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1661 if (reloc_root) {
1662 /*
1663 * btrfs_drop_snapshot drops our ref we hold for
1664 * ->reloc_root. If it fails however we must
1665 * drop the ref ourselves.
1666 */
1667 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1668 if (ret2 < 0) {
1669 btrfs_put_root(reloc_root);
1670 if (!ret)
1671 ret = ret2;
1672 }
1673 }
1674 btrfs_put_root(root);
1675 } else {
1676 /* Orphan reloc tree, just clean it up */
1677 ret2 = btrfs_drop_snapshot(root, 0, 1);
1678 if (ret2 < 0) {
1679 btrfs_put_root(root);
1680 if (!ret)
1681 ret = ret2;
1682 }
1683 }
1684 }
1685 return ret;
1686}
1687
1688/*
1689 * merge the relocated tree blocks in reloc tree with corresponding
1690 * fs tree.
1691 */
1692static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1693 struct btrfs_root *root)
1694{
1695 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1696 struct btrfs_key key;
1697 struct btrfs_key next_key;
1698 struct btrfs_trans_handle *trans = NULL;
1699 struct btrfs_root *reloc_root;
1700 struct btrfs_root_item *root_item;
1701 struct btrfs_path *path;
1702 struct extent_buffer *leaf;
1703 int reserve_level;
1704 int level;
1705 int max_level;
1706 int replaced = 0;
1707 int ret = 0;
1708 u32 min_reserved;
1709
1710 path = btrfs_alloc_path();
1711 if (!path)
1712 return -ENOMEM;
1713 path->reada = READA_FORWARD;
1714
1715 reloc_root = root->reloc_root;
1716 root_item = &reloc_root->root_item;
1717
1718 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1719 level = btrfs_root_level(root_item);
1720 atomic_inc(&reloc_root->node->refs);
1721 path->nodes[level] = reloc_root->node;
1722 path->slots[level] = 0;
1723 } else {
1724 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1725
1726 level = btrfs_root_drop_level(root_item);
1727 BUG_ON(level == 0);
1728 path->lowest_level = level;
1729 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1730 path->lowest_level = 0;
1731 if (ret < 0) {
1732 btrfs_free_path(path);
1733 return ret;
1734 }
1735
1736 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1737 path->slots[level]);
1738 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1739
1740 btrfs_unlock_up_safe(path, 0);
1741 }
1742
1743 /*
1744 * In merge_reloc_root(), we modify the upper level pointer to swap the
1745 * tree blocks between reloc tree and subvolume tree. Thus for tree
1746 * block COW, we COW at most from level 1 to root level for each tree.
1747 *
1748 * Thus the needed metadata size is at most root_level * nodesize,
1749 * and * 2 since we have two trees to COW.
1750 */
1751 reserve_level = max_t(int, 1, btrfs_root_level(root_item));
1752 min_reserved = fs_info->nodesize * reserve_level * 2;
1753 memset(&next_key, 0, sizeof(next_key));
1754
1755 while (1) {
1756 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
1757 min_reserved,
1758 BTRFS_RESERVE_FLUSH_LIMIT);
1759 if (ret)
1760 goto out;
1761 trans = btrfs_start_transaction(root, 0);
1762 if (IS_ERR(trans)) {
1763 ret = PTR_ERR(trans);
1764 trans = NULL;
1765 goto out;
1766 }
1767
1768 /*
1769 * At this point we no longer have a reloc_control, so we can't
1770 * depend on btrfs_init_reloc_root to update our last_trans.
1771 *
1772 * But that's ok, we started the trans handle on our
1773 * corresponding fs_root, which means it's been added to the
1774 * dirty list. At commit time we'll still call
1775 * btrfs_update_reloc_root() and update our root item
1776 * appropriately.
1777 */
1778 reloc_root->last_trans = trans->transid;
1779 trans->block_rsv = rc->block_rsv;
1780
1781 replaced = 0;
1782 max_level = level;
1783
1784 ret = walk_down_reloc_tree(reloc_root, path, &level);
1785 if (ret < 0)
1786 goto out;
1787 if (ret > 0)
1788 break;
1789
1790 if (!find_next_key(path, level, &key) &&
1791 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1792 ret = 0;
1793 } else {
1794 ret = replace_path(trans, rc, root, reloc_root, path,
1795 &next_key, level, max_level);
1796 }
1797 if (ret < 0)
1798 goto out;
1799 if (ret > 0) {
1800 level = ret;
1801 btrfs_node_key_to_cpu(path->nodes[level], &key,
1802 path->slots[level]);
1803 replaced = 1;
1804 }
1805
1806 ret = walk_up_reloc_tree(reloc_root, path, &level);
1807 if (ret > 0)
1808 break;
1809
1810 BUG_ON(level == 0);
1811 /*
1812 * save the merging progress in the drop_progress.
1813 * this is OK since root refs == 1 in this case.
1814 */
1815 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1816 path->slots[level]);
1817 btrfs_set_root_drop_level(root_item, level);
1818
1819 btrfs_end_transaction_throttle(trans);
1820 trans = NULL;
1821
1822 btrfs_btree_balance_dirty(fs_info);
1823
1824 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1825 invalidate_extent_cache(root, &key, &next_key);
1826 }
1827
1828 /*
1829 * handle the case only one block in the fs tree need to be
1830 * relocated and the block is tree root.
1831 */
1832 leaf = btrfs_lock_root_node(root);
1833 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1834 BTRFS_NESTING_COW);
1835 btrfs_tree_unlock(leaf);
1836 free_extent_buffer(leaf);
1837out:
1838 btrfs_free_path(path);
1839
1840 if (ret == 0) {
1841 ret = insert_dirty_subvol(trans, rc, root);
1842 if (ret)
1843 btrfs_abort_transaction(trans, ret);
1844 }
1845
1846 if (trans)
1847 btrfs_end_transaction_throttle(trans);
1848
1849 btrfs_btree_balance_dirty(fs_info);
1850
1851 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1852 invalidate_extent_cache(root, &key, &next_key);
1853
1854 return ret;
1855}
1856
1857static noinline_for_stack
1858int prepare_to_merge(struct reloc_control *rc, int err)
1859{
1860 struct btrfs_root *root = rc->extent_root;
1861 struct btrfs_fs_info *fs_info = root->fs_info;
1862 struct btrfs_root *reloc_root;
1863 struct btrfs_trans_handle *trans;
1864 LIST_HEAD(reloc_roots);
1865 u64 num_bytes = 0;
1866 int ret;
1867
1868 mutex_lock(&fs_info->reloc_mutex);
1869 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1870 rc->merging_rsv_size += rc->nodes_relocated * 2;
1871 mutex_unlock(&fs_info->reloc_mutex);
1872
1873again:
1874 if (!err) {
1875 num_bytes = rc->merging_rsv_size;
1876 ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes,
1877 BTRFS_RESERVE_FLUSH_ALL);
1878 if (ret)
1879 err = ret;
1880 }
1881
1882 trans = btrfs_join_transaction(rc->extent_root);
1883 if (IS_ERR(trans)) {
1884 if (!err)
1885 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1886 num_bytes, NULL);
1887 return PTR_ERR(trans);
1888 }
1889
1890 if (!err) {
1891 if (num_bytes != rc->merging_rsv_size) {
1892 btrfs_end_transaction(trans);
1893 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1894 num_bytes, NULL);
1895 goto again;
1896 }
1897 }
1898
1899 rc->merge_reloc_tree = 1;
1900
1901 while (!list_empty(&rc->reloc_roots)) {
1902 reloc_root = list_entry(rc->reloc_roots.next,
1903 struct btrfs_root, root_list);
1904 list_del_init(&reloc_root->root_list);
1905
1906 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1907 false);
1908 if (IS_ERR(root)) {
1909 /*
1910 * Even if we have an error we need this reloc root
1911 * back on our list so we can clean up properly.
1912 */
1913 list_add(&reloc_root->root_list, &reloc_roots);
1914 btrfs_abort_transaction(trans, (int)PTR_ERR(root));
1915 if (!err)
1916 err = PTR_ERR(root);
1917 break;
1918 }
1919 ASSERT(root->reloc_root == reloc_root);
1920
1921 /*
1922 * set reference count to 1, so btrfs_recover_relocation
1923 * knows it should resumes merging
1924 */
1925 if (!err)
1926 btrfs_set_root_refs(&reloc_root->root_item, 1);
1927 ret = btrfs_update_reloc_root(trans, root);
1928
1929 /*
1930 * Even if we have an error we need this reloc root back on our
1931 * list so we can clean up properly.
1932 */
1933 list_add(&reloc_root->root_list, &reloc_roots);
1934 btrfs_put_root(root);
1935
1936 if (ret) {
1937 btrfs_abort_transaction(trans, ret);
1938 if (!err)
1939 err = ret;
1940 break;
1941 }
1942 }
1943
1944 list_splice(&reloc_roots, &rc->reloc_roots);
1945
1946 if (!err)
1947 err = btrfs_commit_transaction(trans);
1948 else
1949 btrfs_end_transaction(trans);
1950 return err;
1951}
1952
1953static noinline_for_stack
1954void free_reloc_roots(struct list_head *list)
1955{
1956 struct btrfs_root *reloc_root, *tmp;
1957
1958 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1959 __del_reloc_root(reloc_root);
1960}
1961
1962static noinline_for_stack
1963void merge_reloc_roots(struct reloc_control *rc)
1964{
1965 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1966 struct btrfs_root *root;
1967 struct btrfs_root *reloc_root;
1968 LIST_HEAD(reloc_roots);
1969 int found = 0;
1970 int ret = 0;
1971again:
1972 root = rc->extent_root;
1973
1974 /*
1975 * this serializes us with btrfs_record_root_in_transaction,
1976 * we have to make sure nobody is in the middle of
1977 * adding their roots to the list while we are
1978 * doing this splice
1979 */
1980 mutex_lock(&fs_info->reloc_mutex);
1981 list_splice_init(&rc->reloc_roots, &reloc_roots);
1982 mutex_unlock(&fs_info->reloc_mutex);
1983
1984 while (!list_empty(&reloc_roots)) {
1985 found = 1;
1986 reloc_root = list_entry(reloc_roots.next,
1987 struct btrfs_root, root_list);
1988
1989 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1990 false);
1991 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1992 if (IS_ERR(root)) {
1993 /*
1994 * For recovery we read the fs roots on mount,
1995 * and if we didn't find the root then we marked
1996 * the reloc root as a garbage root. For normal
1997 * relocation obviously the root should exist in
1998 * memory. However there's no reason we can't
1999 * handle the error properly here just in case.
2000 */
2001 ASSERT(0);
2002 ret = PTR_ERR(root);
2003 goto out;
2004 }
2005 if (root->reloc_root != reloc_root) {
2006 /*
2007 * This is actually impossible without something
2008 * going really wrong (like weird race condition
2009 * or cosmic rays).
2010 */
2011 ASSERT(0);
2012 ret = -EINVAL;
2013 goto out;
2014 }
2015 ret = merge_reloc_root(rc, root);
2016 btrfs_put_root(root);
2017 if (ret) {
2018 if (list_empty(&reloc_root->root_list))
2019 list_add_tail(&reloc_root->root_list,
2020 &reloc_roots);
2021 goto out;
2022 }
2023 } else {
2024 if (!IS_ERR(root)) {
2025 if (root->reloc_root == reloc_root) {
2026 root->reloc_root = NULL;
2027 btrfs_put_root(reloc_root);
2028 }
2029 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
2030 &root->state);
2031 btrfs_put_root(root);
2032 }
2033
2034 list_del_init(&reloc_root->root_list);
2035 /* Don't forget to queue this reloc root for cleanup */
2036 list_add_tail(&reloc_root->reloc_dirty_list,
2037 &rc->dirty_subvol_roots);
2038 }
2039 }
2040
2041 if (found) {
2042 found = 0;
2043 goto again;
2044 }
2045out:
2046 if (ret) {
2047 btrfs_handle_fs_error(fs_info, ret, NULL);
2048 free_reloc_roots(&reloc_roots);
2049
2050 /* new reloc root may be added */
2051 mutex_lock(&fs_info->reloc_mutex);
2052 list_splice_init(&rc->reloc_roots, &reloc_roots);
2053 mutex_unlock(&fs_info->reloc_mutex);
2054 free_reloc_roots(&reloc_roots);
2055 }
2056
2057 /*
2058 * We used to have
2059 *
2060 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2061 *
2062 * here, but it's wrong. If we fail to start the transaction in
2063 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
2064 * have actually been removed from the reloc_root_tree rb tree. This is
2065 * fine because we're bailing here, and we hold a reference on the root
2066 * for the list that holds it, so these roots will be cleaned up when we
2067 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
2068 * will be cleaned up on unmount.
2069 *
2070 * The remaining nodes will be cleaned up by free_reloc_control.
2071 */
2072}
2073
2074static void free_block_list(struct rb_root *blocks)
2075{
2076 struct tree_block *block;
2077 struct rb_node *rb_node;
2078 while ((rb_node = rb_first(blocks))) {
2079 block = rb_entry(rb_node, struct tree_block, rb_node);
2080 rb_erase(rb_node, blocks);
2081 kfree(block);
2082 }
2083}
2084
2085static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2086 struct btrfs_root *reloc_root)
2087{
2088 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2089 struct btrfs_root *root;
2090 int ret;
2091
2092 if (reloc_root->last_trans == trans->transid)
2093 return 0;
2094
2095 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2096
2097 /*
2098 * This should succeed, since we can't have a reloc root without having
2099 * already looked up the actual root and created the reloc root for this
2100 * root.
2101 *
2102 * However if there's some sort of corruption where we have a ref to a
2103 * reloc root without a corresponding root this could return ENOENT.
2104 */
2105 if (IS_ERR(root)) {
2106 ASSERT(0);
2107 return PTR_ERR(root);
2108 }
2109 if (root->reloc_root != reloc_root) {
2110 ASSERT(0);
2111 btrfs_err(fs_info,
2112 "root %llu has two reloc roots associated with it",
2113 reloc_root->root_key.offset);
2114 btrfs_put_root(root);
2115 return -EUCLEAN;
2116 }
2117 ret = btrfs_record_root_in_trans(trans, root);
2118 btrfs_put_root(root);
2119
2120 return ret;
2121}
2122
2123static noinline_for_stack
2124struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2125 struct reloc_control *rc,
2126 struct btrfs_backref_node *node,
2127 struct btrfs_backref_edge *edges[])
2128{
2129 struct btrfs_backref_node *next;
2130 struct btrfs_root *root;
2131 int index = 0;
2132 int ret;
2133
2134 next = node;
2135 while (1) {
2136 cond_resched();
2137 next = walk_up_backref(next, edges, &index);
2138 root = next->root;
2139
2140 /*
2141 * If there is no root, then our references for this block are
2142 * incomplete, as we should be able to walk all the way up to a
2143 * block that is owned by a root.
2144 *
2145 * This path is only for SHAREABLE roots, so if we come upon a
2146 * non-SHAREABLE root then we have backrefs that resolve
2147 * improperly.
2148 *
2149 * Both of these cases indicate file system corruption, or a bug
2150 * in the backref walking code.
2151 */
2152 if (!root) {
2153 ASSERT(0);
2154 btrfs_err(trans->fs_info,
2155 "bytenr %llu doesn't have a backref path ending in a root",
2156 node->bytenr);
2157 return ERR_PTR(-EUCLEAN);
2158 }
2159 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2160 ASSERT(0);
2161 btrfs_err(trans->fs_info,
2162 "bytenr %llu has multiple refs with one ending in a non-shareable root",
2163 node->bytenr);
2164 return ERR_PTR(-EUCLEAN);
2165 }
2166
2167 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2168 ret = record_reloc_root_in_trans(trans, root);
2169 if (ret)
2170 return ERR_PTR(ret);
2171 break;
2172 }
2173
2174 ret = btrfs_record_root_in_trans(trans, root);
2175 if (ret)
2176 return ERR_PTR(ret);
2177 root = root->reloc_root;
2178
2179 /*
2180 * We could have raced with another thread which failed, so
2181 * root->reloc_root may not be set, return ENOENT in this case.
2182 */
2183 if (!root)
2184 return ERR_PTR(-ENOENT);
2185
2186 if (next->new_bytenr != root->node->start) {
2187 /*
2188 * We just created the reloc root, so we shouldn't have
2189 * ->new_bytenr set and this shouldn't be in the changed
2190 * list. If it is then we have multiple roots pointing
2191 * at the same bytenr which indicates corruption, or
2192 * we've made a mistake in the backref walking code.
2193 */
2194 ASSERT(next->new_bytenr == 0);
2195 ASSERT(list_empty(&next->list));
2196 if (next->new_bytenr || !list_empty(&next->list)) {
2197 btrfs_err(trans->fs_info,
2198 "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
2199 node->bytenr, next->bytenr);
2200 return ERR_PTR(-EUCLEAN);
2201 }
2202
2203 next->new_bytenr = root->node->start;
2204 btrfs_put_root(next->root);
2205 next->root = btrfs_grab_root(root);
2206 ASSERT(next->root);
2207 list_add_tail(&next->list,
2208 &rc->backref_cache.changed);
2209 mark_block_processed(rc, next);
2210 break;
2211 }
2212
2213 WARN_ON(1);
2214 root = NULL;
2215 next = walk_down_backref(edges, &index);
2216 if (!next || next->level <= node->level)
2217 break;
2218 }
2219 if (!root) {
2220 /*
2221 * This can happen if there's fs corruption or if there's a bug
2222 * in the backref lookup code.
2223 */
2224 ASSERT(0);
2225 return ERR_PTR(-ENOENT);
2226 }
2227
2228 next = node;
2229 /* setup backref node path for btrfs_reloc_cow_block */
2230 while (1) {
2231 rc->backref_cache.path[next->level] = next;
2232 if (--index < 0)
2233 break;
2234 next = edges[index]->node[UPPER];
2235 }
2236 return root;
2237}
2238
2239/*
2240 * Select a tree root for relocation.
2241 *
2242 * Return NULL if the block is not shareable. We should use do_relocation() in
2243 * this case.
2244 *
2245 * Return a tree root pointer if the block is shareable.
2246 * Return -ENOENT if the block is root of reloc tree.
2247 */
2248static noinline_for_stack
2249struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2250{
2251 struct btrfs_backref_node *next;
2252 struct btrfs_root *root;
2253 struct btrfs_root *fs_root = NULL;
2254 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2255 int index = 0;
2256
2257 next = node;
2258 while (1) {
2259 cond_resched();
2260 next = walk_up_backref(next, edges, &index);
2261 root = next->root;
2262
2263 /*
2264 * This can occur if we have incomplete extent refs leading all
2265 * the way up a particular path, in this case return -EUCLEAN.
2266 */
2267 if (!root)
2268 return ERR_PTR(-EUCLEAN);
2269
2270 /* No other choice for non-shareable tree */
2271 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2272 return root;
2273
2274 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2275 fs_root = root;
2276
2277 if (next != node)
2278 return NULL;
2279
2280 next = walk_down_backref(edges, &index);
2281 if (!next || next->level <= node->level)
2282 break;
2283 }
2284
2285 if (!fs_root)
2286 return ERR_PTR(-ENOENT);
2287 return fs_root;
2288}
2289
2290static noinline_for_stack
2291u64 calcu_metadata_size(struct reloc_control *rc,
2292 struct btrfs_backref_node *node, int reserve)
2293{
2294 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2295 struct btrfs_backref_node *next = node;
2296 struct btrfs_backref_edge *edge;
2297 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2298 u64 num_bytes = 0;
2299 int index = 0;
2300
2301 BUG_ON(reserve && node->processed);
2302
2303 while (next) {
2304 cond_resched();
2305 while (1) {
2306 if (next->processed && (reserve || next != node))
2307 break;
2308
2309 num_bytes += fs_info->nodesize;
2310
2311 if (list_empty(&next->upper))
2312 break;
2313
2314 edge = list_entry(next->upper.next,
2315 struct btrfs_backref_edge, list[LOWER]);
2316 edges[index++] = edge;
2317 next = edge->node[UPPER];
2318 }
2319 next = walk_down_backref(edges, &index);
2320 }
2321 return num_bytes;
2322}
2323
2324static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2325 struct reloc_control *rc,
2326 struct btrfs_backref_node *node)
2327{
2328 struct btrfs_root *root = rc->extent_root;
2329 struct btrfs_fs_info *fs_info = root->fs_info;
2330 u64 num_bytes;
2331 int ret;
2332 u64 tmp;
2333
2334 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2335
2336 trans->block_rsv = rc->block_rsv;
2337 rc->reserved_bytes += num_bytes;
2338
2339 /*
2340 * We are under a transaction here so we can only do limited flushing.
2341 * If we get an enospc just kick back -EAGAIN so we know to drop the
2342 * transaction and try to refill when we can flush all the things.
2343 */
2344 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
2345 BTRFS_RESERVE_FLUSH_LIMIT);
2346 if (ret) {
2347 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2348 while (tmp <= rc->reserved_bytes)
2349 tmp <<= 1;
2350 /*
2351 * only one thread can access block_rsv at this point,
2352 * so we don't need hold lock to protect block_rsv.
2353 * we expand more reservation size here to allow enough
2354 * space for relocation and we will return earlier in
2355 * enospc case.
2356 */
2357 rc->block_rsv->size = tmp + fs_info->nodesize *
2358 RELOCATION_RESERVED_NODES;
2359 return -EAGAIN;
2360 }
2361
2362 return 0;
2363}
2364
2365/*
2366 * relocate a block tree, and then update pointers in upper level
2367 * blocks that reference the block to point to the new location.
2368 *
2369 * if called by link_to_upper, the block has already been relocated.
2370 * in that case this function just updates pointers.
2371 */
2372static int do_relocation(struct btrfs_trans_handle *trans,
2373 struct reloc_control *rc,
2374 struct btrfs_backref_node *node,
2375 struct btrfs_key *key,
2376 struct btrfs_path *path, int lowest)
2377{
2378 struct btrfs_backref_node *upper;
2379 struct btrfs_backref_edge *edge;
2380 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2381 struct btrfs_root *root;
2382 struct extent_buffer *eb;
2383 u32 blocksize;
2384 u64 bytenr;
2385 int slot;
2386 int ret = 0;
2387
2388 /*
2389 * If we are lowest then this is the first time we're processing this
2390 * block, and thus shouldn't have an eb associated with it yet.
2391 */
2392 ASSERT(!lowest || !node->eb);
2393
2394 path->lowest_level = node->level + 1;
2395 rc->backref_cache.path[node->level] = node;
2396 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2397 struct btrfs_ref ref = { 0 };
2398
2399 cond_resched();
2400
2401 upper = edge->node[UPPER];
2402 root = select_reloc_root(trans, rc, upper, edges);
2403 if (IS_ERR(root)) {
2404 ret = PTR_ERR(root);
2405 goto next;
2406 }
2407
2408 if (upper->eb && !upper->locked) {
2409 if (!lowest) {
2410 ret = btrfs_bin_search(upper->eb, key, &slot);
2411 if (ret < 0)
2412 goto next;
2413 BUG_ON(ret);
2414 bytenr = btrfs_node_blockptr(upper->eb, slot);
2415 if (node->eb->start == bytenr)
2416 goto next;
2417 }
2418 btrfs_backref_drop_node_buffer(upper);
2419 }
2420
2421 if (!upper->eb) {
2422 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2423 if (ret) {
2424 if (ret > 0)
2425 ret = -ENOENT;
2426
2427 btrfs_release_path(path);
2428 break;
2429 }
2430
2431 if (!upper->eb) {
2432 upper->eb = path->nodes[upper->level];
2433 path->nodes[upper->level] = NULL;
2434 } else {
2435 BUG_ON(upper->eb != path->nodes[upper->level]);
2436 }
2437
2438 upper->locked = 1;
2439 path->locks[upper->level] = 0;
2440
2441 slot = path->slots[upper->level];
2442 btrfs_release_path(path);
2443 } else {
2444 ret = btrfs_bin_search(upper->eb, key, &slot);
2445 if (ret < 0)
2446 goto next;
2447 BUG_ON(ret);
2448 }
2449
2450 bytenr = btrfs_node_blockptr(upper->eb, slot);
2451 if (lowest) {
2452 if (bytenr != node->bytenr) {
2453 btrfs_err(root->fs_info,
2454 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2455 bytenr, node->bytenr, slot,
2456 upper->eb->start);
2457 ret = -EIO;
2458 goto next;
2459 }
2460 } else {
2461 if (node->eb->start == bytenr)
2462 goto next;
2463 }
2464
2465 blocksize = root->fs_info->nodesize;
2466 eb = btrfs_read_node_slot(upper->eb, slot);
2467 if (IS_ERR(eb)) {
2468 ret = PTR_ERR(eb);
2469 goto next;
2470 }
2471 btrfs_tree_lock(eb);
2472
2473 if (!node->eb) {
2474 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2475 slot, &eb, BTRFS_NESTING_COW);
2476 btrfs_tree_unlock(eb);
2477 free_extent_buffer(eb);
2478 if (ret < 0)
2479 goto next;
2480 /*
2481 * We've just COWed this block, it should have updated
2482 * the correct backref node entry.
2483 */
2484 ASSERT(node->eb == eb);
2485 } else {
2486 btrfs_set_node_blockptr(upper->eb, slot,
2487 node->eb->start);
2488 btrfs_set_node_ptr_generation(upper->eb, slot,
2489 trans->transid);
2490 btrfs_mark_buffer_dirty(upper->eb);
2491
2492 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2493 node->eb->start, blocksize,
2494 upper->eb->start);
2495 btrfs_init_tree_ref(&ref, node->level,
2496 btrfs_header_owner(upper->eb),
2497 root->root_key.objectid, false);
2498 ret = btrfs_inc_extent_ref(trans, &ref);
2499 if (!ret)
2500 ret = btrfs_drop_subtree(trans, root, eb,
2501 upper->eb);
2502 if (ret)
2503 btrfs_abort_transaction(trans, ret);
2504 }
2505next:
2506 if (!upper->pending)
2507 btrfs_backref_drop_node_buffer(upper);
2508 else
2509 btrfs_backref_unlock_node_buffer(upper);
2510 if (ret)
2511 break;
2512 }
2513
2514 if (!ret && node->pending) {
2515 btrfs_backref_drop_node_buffer(node);
2516 list_move_tail(&node->list, &rc->backref_cache.changed);
2517 node->pending = 0;
2518 }
2519
2520 path->lowest_level = 0;
2521
2522 /*
2523 * We should have allocated all of our space in the block rsv and thus
2524 * shouldn't ENOSPC.
2525 */
2526 ASSERT(ret != -ENOSPC);
2527 return ret;
2528}
2529
2530static int link_to_upper(struct btrfs_trans_handle *trans,
2531 struct reloc_control *rc,
2532 struct btrfs_backref_node *node,
2533 struct btrfs_path *path)
2534{
2535 struct btrfs_key key;
2536
2537 btrfs_node_key_to_cpu(node->eb, &key, 0);
2538 return do_relocation(trans, rc, node, &key, path, 0);
2539}
2540
2541static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2542 struct reloc_control *rc,
2543 struct btrfs_path *path, int err)
2544{
2545 LIST_HEAD(list);
2546 struct btrfs_backref_cache *cache = &rc->backref_cache;
2547 struct btrfs_backref_node *node;
2548 int level;
2549 int ret;
2550
2551 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2552 while (!list_empty(&cache->pending[level])) {
2553 node = list_entry(cache->pending[level].next,
2554 struct btrfs_backref_node, list);
2555 list_move_tail(&node->list, &list);
2556 BUG_ON(!node->pending);
2557
2558 if (!err) {
2559 ret = link_to_upper(trans, rc, node, path);
2560 if (ret < 0)
2561 err = ret;
2562 }
2563 }
2564 list_splice_init(&list, &cache->pending[level]);
2565 }
2566 return err;
2567}
2568
2569/*
2570 * mark a block and all blocks directly/indirectly reference the block
2571 * as processed.
2572 */
2573static void update_processed_blocks(struct reloc_control *rc,
2574 struct btrfs_backref_node *node)
2575{
2576 struct btrfs_backref_node *next = node;
2577 struct btrfs_backref_edge *edge;
2578 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2579 int index = 0;
2580
2581 while (next) {
2582 cond_resched();
2583 while (1) {
2584 if (next->processed)
2585 break;
2586
2587 mark_block_processed(rc, next);
2588
2589 if (list_empty(&next->upper))
2590 break;
2591
2592 edge = list_entry(next->upper.next,
2593 struct btrfs_backref_edge, list[LOWER]);
2594 edges[index++] = edge;
2595 next = edge->node[UPPER];
2596 }
2597 next = walk_down_backref(edges, &index);
2598 }
2599}
2600
2601static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2602{
2603 u32 blocksize = rc->extent_root->fs_info->nodesize;
2604
2605 if (test_range_bit(&rc->processed_blocks, bytenr,
2606 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2607 return 1;
2608 return 0;
2609}
2610
2611static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2612 struct tree_block *block)
2613{
2614 struct btrfs_tree_parent_check check = {
2615 .level = block->level,
2616 .owner_root = block->owner,
2617 .transid = block->key.offset
2618 };
2619 struct extent_buffer *eb;
2620
2621 eb = read_tree_block(fs_info, block->bytenr, &check);
2622 if (IS_ERR(eb))
2623 return PTR_ERR(eb);
2624 if (!extent_buffer_uptodate(eb)) {
2625 free_extent_buffer(eb);
2626 return -EIO;
2627 }
2628 if (block->level == 0)
2629 btrfs_item_key_to_cpu(eb, &block->key, 0);
2630 else
2631 btrfs_node_key_to_cpu(eb, &block->key, 0);
2632 free_extent_buffer(eb);
2633 block->key_ready = 1;
2634 return 0;
2635}
2636
2637/*
2638 * helper function to relocate a tree block
2639 */
2640static int relocate_tree_block(struct btrfs_trans_handle *trans,
2641 struct reloc_control *rc,
2642 struct btrfs_backref_node *node,
2643 struct btrfs_key *key,
2644 struct btrfs_path *path)
2645{
2646 struct btrfs_root *root;
2647 int ret = 0;
2648
2649 if (!node)
2650 return 0;
2651
2652 /*
2653 * If we fail here we want to drop our backref_node because we are going
2654 * to start over and regenerate the tree for it.
2655 */
2656 ret = reserve_metadata_space(trans, rc, node);
2657 if (ret)
2658 goto out;
2659
2660 BUG_ON(node->processed);
2661 root = select_one_root(node);
2662 if (IS_ERR(root)) {
2663 ret = PTR_ERR(root);
2664
2665 /* See explanation in select_one_root for the -EUCLEAN case. */
2666 ASSERT(ret == -ENOENT);
2667 if (ret == -ENOENT) {
2668 ret = 0;
2669 update_processed_blocks(rc, node);
2670 }
2671 goto out;
2672 }
2673
2674 if (root) {
2675 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2676 /*
2677 * This block was the root block of a root, and this is
2678 * the first time we're processing the block and thus it
2679 * should not have had the ->new_bytenr modified and
2680 * should have not been included on the changed list.
2681 *
2682 * However in the case of corruption we could have
2683 * multiple refs pointing to the same block improperly,
2684 * and thus we would trip over these checks. ASSERT()
2685 * for the developer case, because it could indicate a
2686 * bug in the backref code, however error out for a
2687 * normal user in the case of corruption.
2688 */
2689 ASSERT(node->new_bytenr == 0);
2690 ASSERT(list_empty(&node->list));
2691 if (node->new_bytenr || !list_empty(&node->list)) {
2692 btrfs_err(root->fs_info,
2693 "bytenr %llu has improper references to it",
2694 node->bytenr);
2695 ret = -EUCLEAN;
2696 goto out;
2697 }
2698 ret = btrfs_record_root_in_trans(trans, root);
2699 if (ret)
2700 goto out;
2701 /*
2702 * Another thread could have failed, need to check if we
2703 * have reloc_root actually set.
2704 */
2705 if (!root->reloc_root) {
2706 ret = -ENOENT;
2707 goto out;
2708 }
2709 root = root->reloc_root;
2710 node->new_bytenr = root->node->start;
2711 btrfs_put_root(node->root);
2712 node->root = btrfs_grab_root(root);
2713 ASSERT(node->root);
2714 list_add_tail(&node->list, &rc->backref_cache.changed);
2715 } else {
2716 path->lowest_level = node->level;
2717 if (root == root->fs_info->chunk_root)
2718 btrfs_reserve_chunk_metadata(trans, false);
2719 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2720 btrfs_release_path(path);
2721 if (root == root->fs_info->chunk_root)
2722 btrfs_trans_release_chunk_metadata(trans);
2723 if (ret > 0)
2724 ret = 0;
2725 }
2726 if (!ret)
2727 update_processed_blocks(rc, node);
2728 } else {
2729 ret = do_relocation(trans, rc, node, key, path, 1);
2730 }
2731out:
2732 if (ret || node->level == 0 || node->cowonly)
2733 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2734 return ret;
2735}
2736
2737/*
2738 * relocate a list of blocks
2739 */
2740static noinline_for_stack
2741int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2742 struct reloc_control *rc, struct rb_root *blocks)
2743{
2744 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2745 struct btrfs_backref_node *node;
2746 struct btrfs_path *path;
2747 struct tree_block *block;
2748 struct tree_block *next;
2749 int ret;
2750 int err = 0;
2751
2752 path = btrfs_alloc_path();
2753 if (!path) {
2754 err = -ENOMEM;
2755 goto out_free_blocks;
2756 }
2757
2758 /* Kick in readahead for tree blocks with missing keys */
2759 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2760 if (!block->key_ready)
2761 btrfs_readahead_tree_block(fs_info, block->bytenr,
2762 block->owner, 0,
2763 block->level);
2764 }
2765
2766 /* Get first keys */
2767 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2768 if (!block->key_ready) {
2769 err = get_tree_block_key(fs_info, block);
2770 if (err)
2771 goto out_free_path;
2772 }
2773 }
2774
2775 /* Do tree relocation */
2776 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2777 node = build_backref_tree(rc, &block->key,
2778 block->level, block->bytenr);
2779 if (IS_ERR(node)) {
2780 err = PTR_ERR(node);
2781 goto out;
2782 }
2783
2784 ret = relocate_tree_block(trans, rc, node, &block->key,
2785 path);
2786 if (ret < 0) {
2787 err = ret;
2788 break;
2789 }
2790 }
2791out:
2792 err = finish_pending_nodes(trans, rc, path, err);
2793
2794out_free_path:
2795 btrfs_free_path(path);
2796out_free_blocks:
2797 free_block_list(blocks);
2798 return err;
2799}
2800
2801static noinline_for_stack int prealloc_file_extent_cluster(
2802 struct btrfs_inode *inode,
2803 struct file_extent_cluster *cluster)
2804{
2805 u64 alloc_hint = 0;
2806 u64 start;
2807 u64 end;
2808 u64 offset = inode->index_cnt;
2809 u64 num_bytes;
2810 int nr;
2811 int ret = 0;
2812 u64 i_size = i_size_read(&inode->vfs_inode);
2813 u64 prealloc_start = cluster->start - offset;
2814 u64 prealloc_end = cluster->end - offset;
2815 u64 cur_offset = prealloc_start;
2816
2817 /*
2818 * For subpage case, previous i_size may not be aligned to PAGE_SIZE.
2819 * This means the range [i_size, PAGE_END + 1) is filled with zeros by
2820 * btrfs_do_readpage() call of previously relocated file cluster.
2821 *
2822 * If the current cluster starts in the above range, btrfs_do_readpage()
2823 * will skip the read, and relocate_one_page() will later writeback
2824 * the padding zeros as new data, causing data corruption.
2825 *
2826 * Here we have to manually invalidate the range (i_size, PAGE_END + 1).
2827 */
2828 if (!IS_ALIGNED(i_size, PAGE_SIZE)) {
2829 struct address_space *mapping = inode->vfs_inode.i_mapping;
2830 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2831 const u32 sectorsize = fs_info->sectorsize;
2832 struct page *page;
2833
2834 ASSERT(sectorsize < PAGE_SIZE);
2835 ASSERT(IS_ALIGNED(i_size, sectorsize));
2836
2837 /*
2838 * Subpage can't handle page with DIRTY but without UPTODATE
2839 * bit as it can lead to the following deadlock:
2840 *
2841 * btrfs_read_folio()
2842 * | Page already *locked*
2843 * |- btrfs_lock_and_flush_ordered_range()
2844 * |- btrfs_start_ordered_extent()
2845 * |- extent_write_cache_pages()
2846 * |- lock_page()
2847 * We try to lock the page we already hold.
2848 *
2849 * Here we just writeback the whole data reloc inode, so that
2850 * we will be ensured to have no dirty range in the page, and
2851 * are safe to clear the uptodate bits.
2852 *
2853 * This shouldn't cause too much overhead, as we need to write
2854 * the data back anyway.
2855 */
2856 ret = filemap_write_and_wait(mapping);
2857 if (ret < 0)
2858 return ret;
2859
2860 clear_extent_bits(&inode->io_tree, i_size,
2861 round_up(i_size, PAGE_SIZE) - 1,
2862 EXTENT_UPTODATE);
2863 page = find_lock_page(mapping, i_size >> PAGE_SHIFT);
2864 /*
2865 * If page is freed we don't need to do anything then, as we
2866 * will re-read the whole page anyway.
2867 */
2868 if (page) {
2869 btrfs_subpage_clear_uptodate(fs_info, page, i_size,
2870 round_up(i_size, PAGE_SIZE) - i_size);
2871 unlock_page(page);
2872 put_page(page);
2873 }
2874 }
2875
2876 BUG_ON(cluster->start != cluster->boundary[0]);
2877 ret = btrfs_alloc_data_chunk_ondemand(inode,
2878 prealloc_end + 1 - prealloc_start);
2879 if (ret)
2880 return ret;
2881
2882 btrfs_inode_lock(inode, 0);
2883 for (nr = 0; nr < cluster->nr; nr++) {
2884 struct extent_state *cached_state = NULL;
2885
2886 start = cluster->boundary[nr] - offset;
2887 if (nr + 1 < cluster->nr)
2888 end = cluster->boundary[nr + 1] - 1 - offset;
2889 else
2890 end = cluster->end - offset;
2891
2892 lock_extent(&inode->io_tree, start, end, &cached_state);
2893 num_bytes = end + 1 - start;
2894 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2895 num_bytes, num_bytes,
2896 end + 1, &alloc_hint);
2897 cur_offset = end + 1;
2898 unlock_extent(&inode->io_tree, start, end, &cached_state);
2899 if (ret)
2900 break;
2901 }
2902 btrfs_inode_unlock(inode, 0);
2903
2904 if (cur_offset < prealloc_end)
2905 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2906 prealloc_end + 1 - cur_offset);
2907 return ret;
2908}
2909
2910static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode,
2911 u64 start, u64 end, u64 block_start)
2912{
2913 struct extent_map *em;
2914 struct extent_state *cached_state = NULL;
2915 int ret = 0;
2916
2917 em = alloc_extent_map();
2918 if (!em)
2919 return -ENOMEM;
2920
2921 em->start = start;
2922 em->len = end + 1 - start;
2923 em->block_len = em->len;
2924 em->block_start = block_start;
2925 set_bit(EXTENT_FLAG_PINNED, &em->flags);
2926
2927 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2928 ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false);
2929 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2930 free_extent_map(em);
2931
2932 return ret;
2933}
2934
2935/*
2936 * Allow error injection to test balance/relocation cancellation
2937 */
2938noinline int btrfs_should_cancel_balance(struct btrfs_fs_info *fs_info)
2939{
2940 return atomic_read(&fs_info->balance_cancel_req) ||
2941 atomic_read(&fs_info->reloc_cancel_req) ||
2942 fatal_signal_pending(current);
2943}
2944ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2945
2946static u64 get_cluster_boundary_end(struct file_extent_cluster *cluster,
2947 int cluster_nr)
2948{
2949 /* Last extent, use cluster end directly */
2950 if (cluster_nr >= cluster->nr - 1)
2951 return cluster->end;
2952
2953 /* Use next boundary start*/
2954 return cluster->boundary[cluster_nr + 1] - 1;
2955}
2956
2957static int relocate_one_page(struct inode *inode, struct file_ra_state *ra,
2958 struct file_extent_cluster *cluster,
2959 int *cluster_nr, unsigned long page_index)
2960{
2961 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2962 u64 offset = BTRFS_I(inode)->index_cnt;
2963 const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT;
2964 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2965 struct page *page;
2966 u64 page_start;
2967 u64 page_end;
2968 u64 cur;
2969 int ret;
2970
2971 ASSERT(page_index <= last_index);
2972 page = find_lock_page(inode->i_mapping, page_index);
2973 if (!page) {
2974 page_cache_sync_readahead(inode->i_mapping, ra, NULL,
2975 page_index, last_index + 1 - page_index);
2976 page = find_or_create_page(inode->i_mapping, page_index, mask);
2977 if (!page)
2978 return -ENOMEM;
2979 }
2980 ret = set_page_extent_mapped(page);
2981 if (ret < 0)
2982 goto release_page;
2983
2984 if (PageReadahead(page))
2985 page_cache_async_readahead(inode->i_mapping, ra, NULL,
2986 page_folio(page), page_index,
2987 last_index + 1 - page_index);
2988
2989 if (!PageUptodate(page)) {
2990 btrfs_read_folio(NULL, page_folio(page));
2991 lock_page(page);
2992 if (!PageUptodate(page)) {
2993 ret = -EIO;
2994 goto release_page;
2995 }
2996 }
2997
2998 page_start = page_offset(page);
2999 page_end = page_start + PAGE_SIZE - 1;
3000
3001 /*
3002 * Start from the cluster, as for subpage case, the cluster can start
3003 * inside the page.
3004 */
3005 cur = max(page_start, cluster->boundary[*cluster_nr] - offset);
3006 while (cur <= page_end) {
3007 struct extent_state *cached_state = NULL;
3008 u64 extent_start = cluster->boundary[*cluster_nr] - offset;
3009 u64 extent_end = get_cluster_boundary_end(cluster,
3010 *cluster_nr) - offset;
3011 u64 clamped_start = max(page_start, extent_start);
3012 u64 clamped_end = min(page_end, extent_end);
3013 u32 clamped_len = clamped_end + 1 - clamped_start;
3014
3015 /* Reserve metadata for this range */
3016 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3017 clamped_len, clamped_len,
3018 false);
3019 if (ret)
3020 goto release_page;
3021
3022 /* Mark the range delalloc and dirty for later writeback */
3023 lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3024 &cached_state);
3025 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start,
3026 clamped_end, 0, &cached_state);
3027 if (ret) {
3028 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3029 clamped_start, clamped_end,
3030 EXTENT_LOCKED | EXTENT_BOUNDARY,
3031 &cached_state);
3032 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3033 clamped_len, true);
3034 btrfs_delalloc_release_extents(BTRFS_I(inode),
3035 clamped_len);
3036 goto release_page;
3037 }
3038 btrfs_page_set_dirty(fs_info, page, clamped_start, clamped_len);
3039
3040 /*
3041 * Set the boundary if it's inside the page.
3042 * Data relocation requires the destination extents to have the
3043 * same size as the source.
3044 * EXTENT_BOUNDARY bit prevents current extent from being merged
3045 * with previous extent.
3046 */
3047 if (in_range(cluster->boundary[*cluster_nr] - offset,
3048 page_start, PAGE_SIZE)) {
3049 u64 boundary_start = cluster->boundary[*cluster_nr] -
3050 offset;
3051 u64 boundary_end = boundary_start +
3052 fs_info->sectorsize - 1;
3053
3054 set_extent_bits(&BTRFS_I(inode)->io_tree,
3055 boundary_start, boundary_end,
3056 EXTENT_BOUNDARY);
3057 }
3058 unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3059 &cached_state);
3060 btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len);
3061 cur += clamped_len;
3062
3063 /* Crossed extent end, go to next extent */
3064 if (cur >= extent_end) {
3065 (*cluster_nr)++;
3066 /* Just finished the last extent of the cluster, exit. */
3067 if (*cluster_nr >= cluster->nr)
3068 break;
3069 }
3070 }
3071 unlock_page(page);
3072 put_page(page);
3073
3074 balance_dirty_pages_ratelimited(inode->i_mapping);
3075 btrfs_throttle(fs_info);
3076 if (btrfs_should_cancel_balance(fs_info))
3077 ret = -ECANCELED;
3078 return ret;
3079
3080release_page:
3081 unlock_page(page);
3082 put_page(page);
3083 return ret;
3084}
3085
3086static int relocate_file_extent_cluster(struct inode *inode,
3087 struct file_extent_cluster *cluster)
3088{
3089 u64 offset = BTRFS_I(inode)->index_cnt;
3090 unsigned long index;
3091 unsigned long last_index;
3092 struct file_ra_state *ra;
3093 int cluster_nr = 0;
3094 int ret = 0;
3095
3096 if (!cluster->nr)
3097 return 0;
3098
3099 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3100 if (!ra)
3101 return -ENOMEM;
3102
3103 ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
3104 if (ret)
3105 goto out;
3106
3107 file_ra_state_init(ra, inode->i_mapping);
3108
3109 ret = setup_relocation_extent_mapping(inode, cluster->start - offset,
3110 cluster->end - offset, cluster->start);
3111 if (ret)
3112 goto out;
3113
3114 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3115 for (index = (cluster->start - offset) >> PAGE_SHIFT;
3116 index <= last_index && !ret; index++)
3117 ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index);
3118 if (ret == 0)
3119 WARN_ON(cluster_nr != cluster->nr);
3120out:
3121 kfree(ra);
3122 return ret;
3123}
3124
3125static noinline_for_stack
3126int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3127 struct file_extent_cluster *cluster)
3128{
3129 int ret;
3130
3131 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3132 ret = relocate_file_extent_cluster(inode, cluster);
3133 if (ret)
3134 return ret;
3135 cluster->nr = 0;
3136 }
3137
3138 if (!cluster->nr)
3139 cluster->start = extent_key->objectid;
3140 else
3141 BUG_ON(cluster->nr >= MAX_EXTENTS);
3142 cluster->end = extent_key->objectid + extent_key->offset - 1;
3143 cluster->boundary[cluster->nr] = extent_key->objectid;
3144 cluster->nr++;
3145
3146 if (cluster->nr >= MAX_EXTENTS) {
3147 ret = relocate_file_extent_cluster(inode, cluster);
3148 if (ret)
3149 return ret;
3150 cluster->nr = 0;
3151 }
3152 return 0;
3153}
3154
3155/*
3156 * helper to add a tree block to the list.
3157 * the major work is getting the generation and level of the block
3158 */
3159static int add_tree_block(struct reloc_control *rc,
3160 struct btrfs_key *extent_key,
3161 struct btrfs_path *path,
3162 struct rb_root *blocks)
3163{
3164 struct extent_buffer *eb;
3165 struct btrfs_extent_item *ei;
3166 struct btrfs_tree_block_info *bi;
3167 struct tree_block *block;
3168 struct rb_node *rb_node;
3169 u32 item_size;
3170 int level = -1;
3171 u64 generation;
3172 u64 owner = 0;
3173
3174 eb = path->nodes[0];
3175 item_size = btrfs_item_size(eb, path->slots[0]);
3176
3177 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3178 item_size >= sizeof(*ei) + sizeof(*bi)) {
3179 unsigned long ptr = 0, end;
3180
3181 ei = btrfs_item_ptr(eb, path->slots[0],
3182 struct btrfs_extent_item);
3183 end = (unsigned long)ei + item_size;
3184 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3185 bi = (struct btrfs_tree_block_info *)(ei + 1);
3186 level = btrfs_tree_block_level(eb, bi);
3187 ptr = (unsigned long)(bi + 1);
3188 } else {
3189 level = (int)extent_key->offset;
3190 ptr = (unsigned long)(ei + 1);
3191 }
3192 generation = btrfs_extent_generation(eb, ei);
3193
3194 /*
3195 * We're reading random blocks without knowing their owner ahead
3196 * of time. This is ok most of the time, as all reloc roots and
3197 * fs roots have the same lock type. However normal trees do
3198 * not, and the only way to know ahead of time is to read the
3199 * inline ref offset. We know it's an fs root if
3200 *
3201 * 1. There's more than one ref.
3202 * 2. There's a SHARED_DATA_REF_KEY set.
3203 * 3. FULL_BACKREF is set on the flags.
3204 *
3205 * Otherwise it's safe to assume that the ref offset == the
3206 * owner of this block, so we can use that when calling
3207 * read_tree_block.
3208 */
3209 if (btrfs_extent_refs(eb, ei) == 1 &&
3210 !(btrfs_extent_flags(eb, ei) &
3211 BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
3212 ptr < end) {
3213 struct btrfs_extent_inline_ref *iref;
3214 int type;
3215
3216 iref = (struct btrfs_extent_inline_ref *)ptr;
3217 type = btrfs_get_extent_inline_ref_type(eb, iref,
3218 BTRFS_REF_TYPE_BLOCK);
3219 if (type == BTRFS_REF_TYPE_INVALID)
3220 return -EINVAL;
3221 if (type == BTRFS_TREE_BLOCK_REF_KEY)
3222 owner = btrfs_extent_inline_ref_offset(eb, iref);
3223 }
3224 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3225 btrfs_print_v0_err(eb->fs_info);
3226 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3227 return -EINVAL;
3228 } else {
3229 BUG();
3230 }
3231
3232 btrfs_release_path(path);
3233
3234 BUG_ON(level == -1);
3235
3236 block = kmalloc(sizeof(*block), GFP_NOFS);
3237 if (!block)
3238 return -ENOMEM;
3239
3240 block->bytenr = extent_key->objectid;
3241 block->key.objectid = rc->extent_root->fs_info->nodesize;
3242 block->key.offset = generation;
3243 block->level = level;
3244 block->key_ready = 0;
3245 block->owner = owner;
3246
3247 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
3248 if (rb_node)
3249 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
3250 -EEXIST);
3251
3252 return 0;
3253}
3254
3255/*
3256 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3257 */
3258static int __add_tree_block(struct reloc_control *rc,
3259 u64 bytenr, u32 blocksize,
3260 struct rb_root *blocks)
3261{
3262 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3263 struct btrfs_path *path;
3264 struct btrfs_key key;
3265 int ret;
3266 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3267
3268 if (tree_block_processed(bytenr, rc))
3269 return 0;
3270
3271 if (rb_simple_search(blocks, bytenr))
3272 return 0;
3273
3274 path = btrfs_alloc_path();
3275 if (!path)
3276 return -ENOMEM;
3277again:
3278 key.objectid = bytenr;
3279 if (skinny) {
3280 key.type = BTRFS_METADATA_ITEM_KEY;
3281 key.offset = (u64)-1;
3282 } else {
3283 key.type = BTRFS_EXTENT_ITEM_KEY;
3284 key.offset = blocksize;
3285 }
3286
3287 path->search_commit_root = 1;
3288 path->skip_locking = 1;
3289 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3290 if (ret < 0)
3291 goto out;
3292
3293 if (ret > 0 && skinny) {
3294 if (path->slots[0]) {
3295 path->slots[0]--;
3296 btrfs_item_key_to_cpu(path->nodes[0], &key,
3297 path->slots[0]);
3298 if (key.objectid == bytenr &&
3299 (key.type == BTRFS_METADATA_ITEM_KEY ||
3300 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3301 key.offset == blocksize)))
3302 ret = 0;
3303 }
3304
3305 if (ret) {
3306 skinny = false;
3307 btrfs_release_path(path);
3308 goto again;
3309 }
3310 }
3311 if (ret) {
3312 ASSERT(ret == 1);
3313 btrfs_print_leaf(path->nodes[0]);
3314 btrfs_err(fs_info,
3315 "tree block extent item (%llu) is not found in extent tree",
3316 bytenr);
3317 WARN_ON(1);
3318 ret = -EINVAL;
3319 goto out;
3320 }
3321
3322 ret = add_tree_block(rc, &key, path, blocks);
3323out:
3324 btrfs_free_path(path);
3325 return ret;
3326}
3327
3328static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3329 struct btrfs_block_group *block_group,
3330 struct inode *inode,
3331 u64 ino)
3332{
3333 struct btrfs_root *root = fs_info->tree_root;
3334 struct btrfs_trans_handle *trans;
3335 int ret = 0;
3336
3337 if (inode)
3338 goto truncate;
3339
3340 inode = btrfs_iget(fs_info->sb, ino, root);
3341 if (IS_ERR(inode))
3342 return -ENOENT;
3343
3344truncate:
3345 ret = btrfs_check_trunc_cache_free_space(fs_info,
3346 &fs_info->global_block_rsv);
3347 if (ret)
3348 goto out;
3349
3350 trans = btrfs_join_transaction(root);
3351 if (IS_ERR(trans)) {
3352 ret = PTR_ERR(trans);
3353 goto out;
3354 }
3355
3356 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3357
3358 btrfs_end_transaction(trans);
3359 btrfs_btree_balance_dirty(fs_info);
3360out:
3361 iput(inode);
3362 return ret;
3363}
3364
3365/*
3366 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3367 * cache inode, to avoid free space cache data extent blocking data relocation.
3368 */
3369static int delete_v1_space_cache(struct extent_buffer *leaf,
3370 struct btrfs_block_group *block_group,
3371 u64 data_bytenr)
3372{
3373 u64 space_cache_ino;
3374 struct btrfs_file_extent_item *ei;
3375 struct btrfs_key key;
3376 bool found = false;
3377 int i;
3378 int ret;
3379
3380 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3381 return 0;
3382
3383 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3384 u8 type;
3385
3386 btrfs_item_key_to_cpu(leaf, &key, i);
3387 if (key.type != BTRFS_EXTENT_DATA_KEY)
3388 continue;
3389 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3390 type = btrfs_file_extent_type(leaf, ei);
3391
3392 if ((type == BTRFS_FILE_EXTENT_REG ||
3393 type == BTRFS_FILE_EXTENT_PREALLOC) &&
3394 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3395 found = true;
3396 space_cache_ino = key.objectid;
3397 break;
3398 }
3399 }
3400 if (!found)
3401 return -ENOENT;
3402 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3403 space_cache_ino);
3404 return ret;
3405}
3406
3407/*
3408 * helper to find all tree blocks that reference a given data extent
3409 */
3410static noinline_for_stack
3411int add_data_references(struct reloc_control *rc,
3412 struct btrfs_key *extent_key,
3413 struct btrfs_path *path,
3414 struct rb_root *blocks)
3415{
3416 struct btrfs_backref_walk_ctx ctx = { 0 };
3417 struct ulist_iterator leaf_uiter;
3418 struct ulist_node *ref_node = NULL;
3419 const u32 blocksize = rc->extent_root->fs_info->nodesize;
3420 int ret = 0;
3421
3422 btrfs_release_path(path);
3423
3424 ctx.bytenr = extent_key->objectid;
3425 ctx.ignore_extent_item_pos = true;
3426 ctx.fs_info = rc->extent_root->fs_info;
3427
3428 ret = btrfs_find_all_leafs(&ctx);
3429 if (ret < 0)
3430 return ret;
3431
3432 ULIST_ITER_INIT(&leaf_uiter);
3433 while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
3434 struct btrfs_tree_parent_check check = { 0 };
3435 struct extent_buffer *eb;
3436
3437 eb = read_tree_block(ctx.fs_info, ref_node->val, &check);
3438 if (IS_ERR(eb)) {
3439 ret = PTR_ERR(eb);
3440 break;
3441 }
3442 ret = delete_v1_space_cache(eb, rc->block_group,
3443 extent_key->objectid);
3444 free_extent_buffer(eb);
3445 if (ret < 0)
3446 break;
3447 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3448 if (ret < 0)
3449 break;
3450 }
3451 if (ret < 0)
3452 free_block_list(blocks);
3453 ulist_free(ctx.refs);
3454 return ret;
3455}
3456
3457/*
3458 * helper to find next unprocessed extent
3459 */
3460static noinline_for_stack
3461int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3462 struct btrfs_key *extent_key)
3463{
3464 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3465 struct btrfs_key key;
3466 struct extent_buffer *leaf;
3467 u64 start, end, last;
3468 int ret;
3469
3470 last = rc->block_group->start + rc->block_group->length;
3471 while (1) {
3472 cond_resched();
3473 if (rc->search_start >= last) {
3474 ret = 1;
3475 break;
3476 }
3477
3478 key.objectid = rc->search_start;
3479 key.type = BTRFS_EXTENT_ITEM_KEY;
3480 key.offset = 0;
3481
3482 path->search_commit_root = 1;
3483 path->skip_locking = 1;
3484 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3485 0, 0);
3486 if (ret < 0)
3487 break;
3488next:
3489 leaf = path->nodes[0];
3490 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3491 ret = btrfs_next_leaf(rc->extent_root, path);
3492 if (ret != 0)
3493 break;
3494 leaf = path->nodes[0];
3495 }
3496
3497 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3498 if (key.objectid >= last) {
3499 ret = 1;
3500 break;
3501 }
3502
3503 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3504 key.type != BTRFS_METADATA_ITEM_KEY) {
3505 path->slots[0]++;
3506 goto next;
3507 }
3508
3509 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3510 key.objectid + key.offset <= rc->search_start) {
3511 path->slots[0]++;
3512 goto next;
3513 }
3514
3515 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3516 key.objectid + fs_info->nodesize <=
3517 rc->search_start) {
3518 path->slots[0]++;
3519 goto next;
3520 }
3521
3522 ret = find_first_extent_bit(&rc->processed_blocks,
3523 key.objectid, &start, &end,
3524 EXTENT_DIRTY, NULL);
3525
3526 if (ret == 0 && start <= key.objectid) {
3527 btrfs_release_path(path);
3528 rc->search_start = end + 1;
3529 } else {
3530 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3531 rc->search_start = key.objectid + key.offset;
3532 else
3533 rc->search_start = key.objectid +
3534 fs_info->nodesize;
3535 memcpy(extent_key, &key, sizeof(key));
3536 return 0;
3537 }
3538 }
3539 btrfs_release_path(path);
3540 return ret;
3541}
3542
3543static void set_reloc_control(struct reloc_control *rc)
3544{
3545 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3546
3547 mutex_lock(&fs_info->reloc_mutex);
3548 fs_info->reloc_ctl = rc;
3549 mutex_unlock(&fs_info->reloc_mutex);
3550}
3551
3552static void unset_reloc_control(struct reloc_control *rc)
3553{
3554 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3555
3556 mutex_lock(&fs_info->reloc_mutex);
3557 fs_info->reloc_ctl = NULL;
3558 mutex_unlock(&fs_info->reloc_mutex);
3559}
3560
3561static noinline_for_stack
3562int prepare_to_relocate(struct reloc_control *rc)
3563{
3564 struct btrfs_trans_handle *trans;
3565 int ret;
3566
3567 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3568 BTRFS_BLOCK_RSV_TEMP);
3569 if (!rc->block_rsv)
3570 return -ENOMEM;
3571
3572 memset(&rc->cluster, 0, sizeof(rc->cluster));
3573 rc->search_start = rc->block_group->start;
3574 rc->extents_found = 0;
3575 rc->nodes_relocated = 0;
3576 rc->merging_rsv_size = 0;
3577 rc->reserved_bytes = 0;
3578 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3579 RELOCATION_RESERVED_NODES;
3580 ret = btrfs_block_rsv_refill(rc->extent_root->fs_info,
3581 rc->block_rsv, rc->block_rsv->size,
3582 BTRFS_RESERVE_FLUSH_ALL);
3583 if (ret)
3584 return ret;
3585
3586 rc->create_reloc_tree = 1;
3587 set_reloc_control(rc);
3588
3589 trans = btrfs_join_transaction(rc->extent_root);
3590 if (IS_ERR(trans)) {
3591 unset_reloc_control(rc);
3592 /*
3593 * extent tree is not a ref_cow tree and has no reloc_root to
3594 * cleanup. And callers are responsible to free the above
3595 * block rsv.
3596 */
3597 return PTR_ERR(trans);
3598 }
3599
3600 ret = btrfs_commit_transaction(trans);
3601 if (ret)
3602 unset_reloc_control(rc);
3603
3604 return ret;
3605}
3606
3607static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3608{
3609 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3610 struct rb_root blocks = RB_ROOT;
3611 struct btrfs_key key;
3612 struct btrfs_trans_handle *trans = NULL;
3613 struct btrfs_path *path;
3614 struct btrfs_extent_item *ei;
3615 u64 flags;
3616 int ret;
3617 int err = 0;
3618 int progress = 0;
3619
3620 path = btrfs_alloc_path();
3621 if (!path)
3622 return -ENOMEM;
3623 path->reada = READA_FORWARD;
3624
3625 ret = prepare_to_relocate(rc);
3626 if (ret) {
3627 err = ret;
3628 goto out_free;
3629 }
3630
3631 while (1) {
3632 rc->reserved_bytes = 0;
3633 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
3634 rc->block_rsv->size,
3635 BTRFS_RESERVE_FLUSH_ALL);
3636 if (ret) {
3637 err = ret;
3638 break;
3639 }
3640 progress++;
3641 trans = btrfs_start_transaction(rc->extent_root, 0);
3642 if (IS_ERR(trans)) {
3643 err = PTR_ERR(trans);
3644 trans = NULL;
3645 break;
3646 }
3647restart:
3648 if (update_backref_cache(trans, &rc->backref_cache)) {
3649 btrfs_end_transaction(trans);
3650 trans = NULL;
3651 continue;
3652 }
3653
3654 ret = find_next_extent(rc, path, &key);
3655 if (ret < 0)
3656 err = ret;
3657 if (ret != 0)
3658 break;
3659
3660 rc->extents_found++;
3661
3662 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3663 struct btrfs_extent_item);
3664 flags = btrfs_extent_flags(path->nodes[0], ei);
3665
3666 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3667 ret = add_tree_block(rc, &key, path, &blocks);
3668 } else if (rc->stage == UPDATE_DATA_PTRS &&
3669 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3670 ret = add_data_references(rc, &key, path, &blocks);
3671 } else {
3672 btrfs_release_path(path);
3673 ret = 0;
3674 }
3675 if (ret < 0) {
3676 err = ret;
3677 break;
3678 }
3679
3680 if (!RB_EMPTY_ROOT(&blocks)) {
3681 ret = relocate_tree_blocks(trans, rc, &blocks);
3682 if (ret < 0) {
3683 if (ret != -EAGAIN) {
3684 err = ret;
3685 break;
3686 }
3687 rc->extents_found--;
3688 rc->search_start = key.objectid;
3689 }
3690 }
3691
3692 btrfs_end_transaction_throttle(trans);
3693 btrfs_btree_balance_dirty(fs_info);
3694 trans = NULL;
3695
3696 if (rc->stage == MOVE_DATA_EXTENTS &&
3697 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3698 rc->found_file_extent = 1;
3699 ret = relocate_data_extent(rc->data_inode,
3700 &key, &rc->cluster);
3701 if (ret < 0) {
3702 err = ret;
3703 break;
3704 }
3705 }
3706 if (btrfs_should_cancel_balance(fs_info)) {
3707 err = -ECANCELED;
3708 break;
3709 }
3710 }
3711 if (trans && progress && err == -ENOSPC) {
3712 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3713 if (ret == 1) {
3714 err = 0;
3715 progress = 0;
3716 goto restart;
3717 }
3718 }
3719
3720 btrfs_release_path(path);
3721 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3722
3723 if (trans) {
3724 btrfs_end_transaction_throttle(trans);
3725 btrfs_btree_balance_dirty(fs_info);
3726 }
3727
3728 if (!err) {
3729 ret = relocate_file_extent_cluster(rc->data_inode,
3730 &rc->cluster);
3731 if (ret < 0)
3732 err = ret;
3733 }
3734
3735 rc->create_reloc_tree = 0;
3736 set_reloc_control(rc);
3737
3738 btrfs_backref_release_cache(&rc->backref_cache);
3739 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3740
3741 /*
3742 * Even in the case when the relocation is cancelled, we should all go
3743 * through prepare_to_merge() and merge_reloc_roots().
3744 *
3745 * For error (including cancelled balance), prepare_to_merge() will
3746 * mark all reloc trees orphan, then queue them for cleanup in
3747 * merge_reloc_roots()
3748 */
3749 err = prepare_to_merge(rc, err);
3750
3751 merge_reloc_roots(rc);
3752
3753 rc->merge_reloc_tree = 0;
3754 unset_reloc_control(rc);
3755 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3756
3757 /* get rid of pinned extents */
3758 trans = btrfs_join_transaction(rc->extent_root);
3759 if (IS_ERR(trans)) {
3760 err = PTR_ERR(trans);
3761 goto out_free;
3762 }
3763 ret = btrfs_commit_transaction(trans);
3764 if (ret && !err)
3765 err = ret;
3766out_free:
3767 ret = clean_dirty_subvols(rc);
3768 if (ret < 0 && !err)
3769 err = ret;
3770 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3771 btrfs_free_path(path);
3772 return err;
3773}
3774
3775static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3776 struct btrfs_root *root, u64 objectid)
3777{
3778 struct btrfs_path *path;
3779 struct btrfs_inode_item *item;
3780 struct extent_buffer *leaf;
3781 int ret;
3782
3783 path = btrfs_alloc_path();
3784 if (!path)
3785 return -ENOMEM;
3786
3787 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3788 if (ret)
3789 goto out;
3790
3791 leaf = path->nodes[0];
3792 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3793 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3794 btrfs_set_inode_generation(leaf, item, 1);
3795 btrfs_set_inode_size(leaf, item, 0);
3796 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3797 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3798 BTRFS_INODE_PREALLOC);
3799 btrfs_mark_buffer_dirty(leaf);
3800out:
3801 btrfs_free_path(path);
3802 return ret;
3803}
3804
3805static void delete_orphan_inode(struct btrfs_trans_handle *trans,
3806 struct btrfs_root *root, u64 objectid)
3807{
3808 struct btrfs_path *path;
3809 struct btrfs_key key;
3810 int ret = 0;
3811
3812 path = btrfs_alloc_path();
3813 if (!path) {
3814 ret = -ENOMEM;
3815 goto out;
3816 }
3817
3818 key.objectid = objectid;
3819 key.type = BTRFS_INODE_ITEM_KEY;
3820 key.offset = 0;
3821 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3822 if (ret) {
3823 if (ret > 0)
3824 ret = -ENOENT;
3825 goto out;
3826 }
3827 ret = btrfs_del_item(trans, root, path);
3828out:
3829 if (ret)
3830 btrfs_abort_transaction(trans, ret);
3831 btrfs_free_path(path);
3832}
3833
3834/*
3835 * helper to create inode for data relocation.
3836 * the inode is in data relocation tree and its link count is 0
3837 */
3838static noinline_for_stack
3839struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
3840 struct btrfs_block_group *group)
3841{
3842 struct inode *inode = NULL;
3843 struct btrfs_trans_handle *trans;
3844 struct btrfs_root *root;
3845 u64 objectid;
3846 int err = 0;
3847
3848 root = btrfs_grab_root(fs_info->data_reloc_root);
3849 trans = btrfs_start_transaction(root, 6);
3850 if (IS_ERR(trans)) {
3851 btrfs_put_root(root);
3852 return ERR_CAST(trans);
3853 }
3854
3855 err = btrfs_get_free_objectid(root, &objectid);
3856 if (err)
3857 goto out;
3858
3859 err = __insert_orphan_inode(trans, root, objectid);
3860 if (err)
3861 goto out;
3862
3863 inode = btrfs_iget(fs_info->sb, objectid, root);
3864 if (IS_ERR(inode)) {
3865 delete_orphan_inode(trans, root, objectid);
3866 err = PTR_ERR(inode);
3867 inode = NULL;
3868 goto out;
3869 }
3870 BTRFS_I(inode)->index_cnt = group->start;
3871
3872 err = btrfs_orphan_add(trans, BTRFS_I(inode));
3873out:
3874 btrfs_put_root(root);
3875 btrfs_end_transaction(trans);
3876 btrfs_btree_balance_dirty(fs_info);
3877 if (err) {
3878 iput(inode);
3879 inode = ERR_PTR(err);
3880 }
3881 return inode;
3882}
3883
3884/*
3885 * Mark start of chunk relocation that is cancellable. Check if the cancellation
3886 * has been requested meanwhile and don't start in that case.
3887 *
3888 * Return:
3889 * 0 success
3890 * -EINPROGRESS operation is already in progress, that's probably a bug
3891 * -ECANCELED cancellation request was set before the operation started
3892 */
3893static int reloc_chunk_start(struct btrfs_fs_info *fs_info)
3894{
3895 if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) {
3896 /* This should not happen */
3897 btrfs_err(fs_info, "reloc already running, cannot start");
3898 return -EINPROGRESS;
3899 }
3900
3901 if (atomic_read(&fs_info->reloc_cancel_req) > 0) {
3902 btrfs_info(fs_info, "chunk relocation canceled on start");
3903 /*
3904 * On cancel, clear all requests but let the caller mark
3905 * the end after cleanup operations.
3906 */
3907 atomic_set(&fs_info->reloc_cancel_req, 0);
3908 return -ECANCELED;
3909 }
3910 return 0;
3911}
3912
3913/*
3914 * Mark end of chunk relocation that is cancellable and wake any waiters.
3915 */
3916static void reloc_chunk_end(struct btrfs_fs_info *fs_info)
3917{
3918 /* Requested after start, clear bit first so any waiters can continue */
3919 if (atomic_read(&fs_info->reloc_cancel_req) > 0)
3920 btrfs_info(fs_info, "chunk relocation canceled during operation");
3921 clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags);
3922 atomic_set(&fs_info->reloc_cancel_req, 0);
3923}
3924
3925static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3926{
3927 struct reloc_control *rc;
3928
3929 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3930 if (!rc)
3931 return NULL;
3932
3933 INIT_LIST_HEAD(&rc->reloc_roots);
3934 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
3935 btrfs_backref_init_cache(fs_info, &rc->backref_cache, 1);
3936 mapping_tree_init(&rc->reloc_root_tree);
3937 extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS);
3938 return rc;
3939}
3940
3941static void free_reloc_control(struct reloc_control *rc)
3942{
3943 struct mapping_node *node, *tmp;
3944
3945 free_reloc_roots(&rc->reloc_roots);
3946 rbtree_postorder_for_each_entry_safe(node, tmp,
3947 &rc->reloc_root_tree.rb_root, rb_node)
3948 kfree(node);
3949
3950 kfree(rc);
3951}
3952
3953/*
3954 * Print the block group being relocated
3955 */
3956static void describe_relocation(struct btrfs_fs_info *fs_info,
3957 struct btrfs_block_group *block_group)
3958{
3959 char buf[128] = {'\0'};
3960
3961 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
3962
3963 btrfs_info(fs_info,
3964 "relocating block group %llu flags %s",
3965 block_group->start, buf);
3966}
3967
3968static const char *stage_to_string(int stage)
3969{
3970 if (stage == MOVE_DATA_EXTENTS)
3971 return "move data extents";
3972 if (stage == UPDATE_DATA_PTRS)
3973 return "update data pointers";
3974 return "unknown";
3975}
3976
3977/*
3978 * function to relocate all extents in a block group.
3979 */
3980int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
3981{
3982 struct btrfs_block_group *bg;
3983 struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start);
3984 struct reloc_control *rc;
3985 struct inode *inode;
3986 struct btrfs_path *path;
3987 int ret;
3988 int rw = 0;
3989 int err = 0;
3990
3991 /*
3992 * This only gets set if we had a half-deleted snapshot on mount. We
3993 * cannot allow relocation to start while we're still trying to clean up
3994 * these pending deletions.
3995 */
3996 ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
3997 if (ret)
3998 return ret;
3999
4000 /* We may have been woken up by close_ctree, so bail if we're closing. */
4001 if (btrfs_fs_closing(fs_info))
4002 return -EINTR;
4003
4004 bg = btrfs_lookup_block_group(fs_info, group_start);
4005 if (!bg)
4006 return -ENOENT;
4007
4008 /*
4009 * Relocation of a data block group creates ordered extents. Without
4010 * sb_start_write(), we can freeze the filesystem while unfinished
4011 * ordered extents are left. Such ordered extents can cause a deadlock
4012 * e.g. when syncfs() is waiting for their completion but they can't
4013 * finish because they block when joining a transaction, due to the
4014 * fact that the freeze locks are being held in write mode.
4015 */
4016 if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
4017 ASSERT(sb_write_started(fs_info->sb));
4018
4019 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4020 btrfs_put_block_group(bg);
4021 return -ETXTBSY;
4022 }
4023
4024 rc = alloc_reloc_control(fs_info);
4025 if (!rc) {
4026 btrfs_put_block_group(bg);
4027 return -ENOMEM;
4028 }
4029
4030 ret = reloc_chunk_start(fs_info);
4031 if (ret < 0) {
4032 err = ret;
4033 goto out_put_bg;
4034 }
4035
4036 rc->extent_root = extent_root;
4037 rc->block_group = bg;
4038
4039 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4040 if (ret) {
4041 err = ret;
4042 goto out;
4043 }
4044 rw = 1;
4045
4046 path = btrfs_alloc_path();
4047 if (!path) {
4048 err = -ENOMEM;
4049 goto out;
4050 }
4051
4052 inode = lookup_free_space_inode(rc->block_group, path);
4053 btrfs_free_path(path);
4054
4055 if (!IS_ERR(inode))
4056 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4057 else
4058 ret = PTR_ERR(inode);
4059
4060 if (ret && ret != -ENOENT) {
4061 err = ret;
4062 goto out;
4063 }
4064
4065 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4066 if (IS_ERR(rc->data_inode)) {
4067 err = PTR_ERR(rc->data_inode);
4068 rc->data_inode = NULL;
4069 goto out;
4070 }
4071
4072 describe_relocation(fs_info, rc->block_group);
4073
4074 btrfs_wait_block_group_reservations(rc->block_group);
4075 btrfs_wait_nocow_writers(rc->block_group);
4076 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4077 rc->block_group->start,
4078 rc->block_group->length);
4079
4080 ret = btrfs_zone_finish(rc->block_group);
4081 WARN_ON(ret && ret != -EAGAIN);
4082
4083 while (1) {
4084 int finishes_stage;
4085
4086 mutex_lock(&fs_info->cleaner_mutex);
4087 ret = relocate_block_group(rc);
4088 mutex_unlock(&fs_info->cleaner_mutex);
4089 if (ret < 0)
4090 err = ret;
4091
4092 finishes_stage = rc->stage;
4093 /*
4094 * We may have gotten ENOSPC after we already dirtied some
4095 * extents. If writeout happens while we're relocating a
4096 * different block group we could end up hitting the
4097 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4098 * btrfs_reloc_cow_block. Make sure we write everything out
4099 * properly so we don't trip over this problem, and then break
4100 * out of the loop if we hit an error.
4101 */
4102 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4103 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4104 (u64)-1);
4105 if (ret)
4106 err = ret;
4107 invalidate_mapping_pages(rc->data_inode->i_mapping,
4108 0, -1);
4109 rc->stage = UPDATE_DATA_PTRS;
4110 }
4111
4112 if (err < 0)
4113 goto out;
4114
4115 if (rc->extents_found == 0)
4116 break;
4117
4118 btrfs_info(fs_info, "found %llu extents, stage: %s",
4119 rc->extents_found, stage_to_string(finishes_stage));
4120 }
4121
4122 WARN_ON(rc->block_group->pinned > 0);
4123 WARN_ON(rc->block_group->reserved > 0);
4124 WARN_ON(rc->block_group->used > 0);
4125out:
4126 if (err && rw)
4127 btrfs_dec_block_group_ro(rc->block_group);
4128 iput(rc->data_inode);
4129out_put_bg:
4130 btrfs_put_block_group(bg);
4131 reloc_chunk_end(fs_info);
4132 free_reloc_control(rc);
4133 return err;
4134}
4135
4136static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4137{
4138 struct btrfs_fs_info *fs_info = root->fs_info;
4139 struct btrfs_trans_handle *trans;
4140 int ret, err;
4141
4142 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4143 if (IS_ERR(trans))
4144 return PTR_ERR(trans);
4145
4146 memset(&root->root_item.drop_progress, 0,
4147 sizeof(root->root_item.drop_progress));
4148 btrfs_set_root_drop_level(&root->root_item, 0);
4149 btrfs_set_root_refs(&root->root_item, 0);
4150 ret = btrfs_update_root(trans, fs_info->tree_root,
4151 &root->root_key, &root->root_item);
4152
4153 err = btrfs_end_transaction(trans);
4154 if (err)
4155 return err;
4156 return ret;
4157}
4158
4159/*
4160 * recover relocation interrupted by system crash.
4161 *
4162 * this function resumes merging reloc trees with corresponding fs trees.
4163 * this is important for keeping the sharing of tree blocks
4164 */
4165int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
4166{
4167 LIST_HEAD(reloc_roots);
4168 struct btrfs_key key;
4169 struct btrfs_root *fs_root;
4170 struct btrfs_root *reloc_root;
4171 struct btrfs_path *path;
4172 struct extent_buffer *leaf;
4173 struct reloc_control *rc = NULL;
4174 struct btrfs_trans_handle *trans;
4175 int ret;
4176 int err = 0;
4177
4178 path = btrfs_alloc_path();
4179 if (!path)
4180 return -ENOMEM;
4181 path->reada = READA_BACK;
4182
4183 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4184 key.type = BTRFS_ROOT_ITEM_KEY;
4185 key.offset = (u64)-1;
4186
4187 while (1) {
4188 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4189 path, 0, 0);
4190 if (ret < 0) {
4191 err = ret;
4192 goto out;
4193 }
4194 if (ret > 0) {
4195 if (path->slots[0] == 0)
4196 break;
4197 path->slots[0]--;
4198 }
4199 leaf = path->nodes[0];
4200 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4201 btrfs_release_path(path);
4202
4203 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4204 key.type != BTRFS_ROOT_ITEM_KEY)
4205 break;
4206
4207 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
4208 if (IS_ERR(reloc_root)) {
4209 err = PTR_ERR(reloc_root);
4210 goto out;
4211 }
4212
4213 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
4214 list_add(&reloc_root->root_list, &reloc_roots);
4215
4216 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4217 fs_root = btrfs_get_fs_root(fs_info,
4218 reloc_root->root_key.offset, false);
4219 if (IS_ERR(fs_root)) {
4220 ret = PTR_ERR(fs_root);
4221 if (ret != -ENOENT) {
4222 err = ret;
4223 goto out;
4224 }
4225 ret = mark_garbage_root(reloc_root);
4226 if (ret < 0) {
4227 err = ret;
4228 goto out;
4229 }
4230 } else {
4231 btrfs_put_root(fs_root);
4232 }
4233 }
4234
4235 if (key.offset == 0)
4236 break;
4237
4238 key.offset--;
4239 }
4240 btrfs_release_path(path);
4241
4242 if (list_empty(&reloc_roots))
4243 goto out;
4244
4245 rc = alloc_reloc_control(fs_info);
4246 if (!rc) {
4247 err = -ENOMEM;
4248 goto out;
4249 }
4250
4251 ret = reloc_chunk_start(fs_info);
4252 if (ret < 0) {
4253 err = ret;
4254 goto out_end;
4255 }
4256
4257 rc->extent_root = btrfs_extent_root(fs_info, 0);
4258
4259 set_reloc_control(rc);
4260
4261 trans = btrfs_join_transaction(rc->extent_root);
4262 if (IS_ERR(trans)) {
4263 err = PTR_ERR(trans);
4264 goto out_unset;
4265 }
4266
4267 rc->merge_reloc_tree = 1;
4268
4269 while (!list_empty(&reloc_roots)) {
4270 reloc_root = list_entry(reloc_roots.next,
4271 struct btrfs_root, root_list);
4272 list_del(&reloc_root->root_list);
4273
4274 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4275 list_add_tail(&reloc_root->root_list,
4276 &rc->reloc_roots);
4277 continue;
4278 }
4279
4280 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
4281 false);
4282 if (IS_ERR(fs_root)) {
4283 err = PTR_ERR(fs_root);
4284 list_add_tail(&reloc_root->root_list, &reloc_roots);
4285 btrfs_end_transaction(trans);
4286 goto out_unset;
4287 }
4288
4289 err = __add_reloc_root(reloc_root);
4290 ASSERT(err != -EEXIST);
4291 if (err) {
4292 list_add_tail(&reloc_root->root_list, &reloc_roots);
4293 btrfs_put_root(fs_root);
4294 btrfs_end_transaction(trans);
4295 goto out_unset;
4296 }
4297 fs_root->reloc_root = btrfs_grab_root(reloc_root);
4298 btrfs_put_root(fs_root);
4299 }
4300
4301 err = btrfs_commit_transaction(trans);
4302 if (err)
4303 goto out_unset;
4304
4305 merge_reloc_roots(rc);
4306
4307 unset_reloc_control(rc);
4308
4309 trans = btrfs_join_transaction(rc->extent_root);
4310 if (IS_ERR(trans)) {
4311 err = PTR_ERR(trans);
4312 goto out_clean;
4313 }
4314 err = btrfs_commit_transaction(trans);
4315out_clean:
4316 ret = clean_dirty_subvols(rc);
4317 if (ret < 0 && !err)
4318 err = ret;
4319out_unset:
4320 unset_reloc_control(rc);
4321out_end:
4322 reloc_chunk_end(fs_info);
4323 free_reloc_control(rc);
4324out:
4325 free_reloc_roots(&reloc_roots);
4326
4327 btrfs_free_path(path);
4328
4329 if (err == 0) {
4330 /* cleanup orphan inode in data relocation tree */
4331 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
4332 ASSERT(fs_root);
4333 err = btrfs_orphan_cleanup(fs_root);
4334 btrfs_put_root(fs_root);
4335 }
4336 return err;
4337}
4338
4339/*
4340 * helper to add ordered checksum for data relocation.
4341 *
4342 * cloning checksum properly handles the nodatasum extents.
4343 * it also saves CPU time to re-calculate the checksum.
4344 */
4345int btrfs_reloc_clone_csums(struct btrfs_inode *inode, u64 file_pos, u64 len)
4346{
4347 struct btrfs_fs_info *fs_info = inode->root->fs_info;
4348 struct btrfs_root *csum_root;
4349 struct btrfs_ordered_sum *sums;
4350 struct btrfs_ordered_extent *ordered;
4351 int ret;
4352 u64 disk_bytenr;
4353 u64 new_bytenr;
4354 LIST_HEAD(list);
4355
4356 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4357 BUG_ON(ordered->file_offset != file_pos || ordered->num_bytes != len);
4358
4359 disk_bytenr = file_pos + inode->index_cnt;
4360 csum_root = btrfs_csum_root(fs_info, disk_bytenr);
4361 ret = btrfs_lookup_csums_list(csum_root, disk_bytenr,
4362 disk_bytenr + len - 1, &list, 0, false);
4363 if (ret)
4364 goto out;
4365
4366 while (!list_empty(&list)) {
4367 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4368 list_del_init(&sums->list);
4369
4370 /*
4371 * We need to offset the new_bytenr based on where the csum is.
4372 * We need to do this because we will read in entire prealloc
4373 * extents but we may have written to say the middle of the
4374 * prealloc extent, so we need to make sure the csum goes with
4375 * the right disk offset.
4376 *
4377 * We can do this because the data reloc inode refers strictly
4378 * to the on disk bytes, so we don't have to worry about
4379 * disk_len vs real len like with real inodes since it's all
4380 * disk length.
4381 */
4382 new_bytenr = ordered->disk_bytenr + sums->bytenr - disk_bytenr;
4383 sums->bytenr = new_bytenr;
4384
4385 btrfs_add_ordered_sum(ordered, sums);
4386 }
4387out:
4388 btrfs_put_ordered_extent(ordered);
4389 return ret;
4390}
4391
4392int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4393 struct btrfs_root *root, struct extent_buffer *buf,
4394 struct extent_buffer *cow)
4395{
4396 struct btrfs_fs_info *fs_info = root->fs_info;
4397 struct reloc_control *rc;
4398 struct btrfs_backref_node *node;
4399 int first_cow = 0;
4400 int level;
4401 int ret = 0;
4402
4403 rc = fs_info->reloc_ctl;
4404 if (!rc)
4405 return 0;
4406
4407 BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root));
4408
4409 level = btrfs_header_level(buf);
4410 if (btrfs_header_generation(buf) <=
4411 btrfs_root_last_snapshot(&root->root_item))
4412 first_cow = 1;
4413
4414 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4415 rc->create_reloc_tree) {
4416 WARN_ON(!first_cow && level == 0);
4417
4418 node = rc->backref_cache.path[level];
4419 BUG_ON(node->bytenr != buf->start &&
4420 node->new_bytenr != buf->start);
4421
4422 btrfs_backref_drop_node_buffer(node);
4423 atomic_inc(&cow->refs);
4424 node->eb = cow;
4425 node->new_bytenr = cow->start;
4426
4427 if (!node->pending) {
4428 list_move_tail(&node->list,
4429 &rc->backref_cache.pending[level]);
4430 node->pending = 1;
4431 }
4432
4433 if (first_cow)
4434 mark_block_processed(rc, node);
4435
4436 if (first_cow && level > 0)
4437 rc->nodes_relocated += buf->len;
4438 }
4439
4440 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4441 ret = replace_file_extents(trans, rc, root, cow);
4442 return ret;
4443}
4444
4445/*
4446 * called before creating snapshot. it calculates metadata reservation
4447 * required for relocating tree blocks in the snapshot
4448 */
4449void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4450 u64 *bytes_to_reserve)
4451{
4452 struct btrfs_root *root = pending->root;
4453 struct reloc_control *rc = root->fs_info->reloc_ctl;
4454
4455 if (!rc || !have_reloc_root(root))
4456 return;
4457
4458 if (!rc->merge_reloc_tree)
4459 return;
4460
4461 root = root->reloc_root;
4462 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4463 /*
4464 * relocation is in the stage of merging trees. the space
4465 * used by merging a reloc tree is twice the size of
4466 * relocated tree nodes in the worst case. half for cowing
4467 * the reloc tree, half for cowing the fs tree. the space
4468 * used by cowing the reloc tree will be freed after the
4469 * tree is dropped. if we create snapshot, cowing the fs
4470 * tree may use more space than it frees. so we need
4471 * reserve extra space.
4472 */
4473 *bytes_to_reserve += rc->nodes_relocated;
4474}
4475
4476/*
4477 * called after snapshot is created. migrate block reservation
4478 * and create reloc root for the newly created snapshot
4479 *
4480 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4481 * references held on the reloc_root, one for root->reloc_root and one for
4482 * rc->reloc_roots.
4483 */
4484int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4485 struct btrfs_pending_snapshot *pending)
4486{
4487 struct btrfs_root *root = pending->root;
4488 struct btrfs_root *reloc_root;
4489 struct btrfs_root *new_root;
4490 struct reloc_control *rc = root->fs_info->reloc_ctl;
4491 int ret;
4492
4493 if (!rc || !have_reloc_root(root))
4494 return 0;
4495
4496 rc = root->fs_info->reloc_ctl;
4497 rc->merging_rsv_size += rc->nodes_relocated;
4498
4499 if (rc->merge_reloc_tree) {
4500 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4501 rc->block_rsv,
4502 rc->nodes_relocated, true);
4503 if (ret)
4504 return ret;
4505 }
4506
4507 new_root = pending->snap;
4508 reloc_root = create_reloc_root(trans, root->reloc_root,
4509 new_root->root_key.objectid);
4510 if (IS_ERR(reloc_root))
4511 return PTR_ERR(reloc_root);
4512
4513 ret = __add_reloc_root(reloc_root);
4514 ASSERT(ret != -EEXIST);
4515 if (ret) {
4516 /* Pairs with create_reloc_root */
4517 btrfs_put_root(reloc_root);
4518 return ret;
4519 }
4520 new_root->reloc_root = btrfs_grab_root(reloc_root);
4521
4522 if (rc->create_reloc_tree)
4523 ret = clone_backref_node(trans, rc, root, reloc_root);
4524 return ret;
4525}