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1/*
2 * Copyright (C) 2009 Oracle. All rights reserved.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
17 */
18
19#include <linux/sched.h>
20#include <linux/pagemap.h>
21#include <linux/writeback.h>
22#include <linux/blkdev.h>
23#include <linux/rbtree.h>
24#include <linux/slab.h>
25#include "ctree.h"
26#include "disk-io.h"
27#include "transaction.h"
28#include "volumes.h"
29#include "locking.h"
30#include "btrfs_inode.h"
31#include "async-thread.h"
32#include "free-space-cache.h"
33#include "inode-map.h"
34#include "qgroup.h"
35
36/*
37 * backref_node, mapping_node and tree_block start with this
38 */
39struct tree_entry {
40 struct rb_node rb_node;
41 u64 bytenr;
42};
43
44/*
45 * present a tree block in the backref cache
46 */
47struct backref_node {
48 struct rb_node rb_node;
49 u64 bytenr;
50
51 u64 new_bytenr;
52 /* objectid of tree block owner, can be not uptodate */
53 u64 owner;
54 /* link to pending, changed or detached list */
55 struct list_head list;
56 /* list of upper level blocks reference this block */
57 struct list_head upper;
58 /* list of child blocks in the cache */
59 struct list_head lower;
60 /* NULL if this node is not tree root */
61 struct btrfs_root *root;
62 /* extent buffer got by COW the block */
63 struct extent_buffer *eb;
64 /* level of tree block */
65 unsigned int level:8;
66 /* is the block in non-reference counted tree */
67 unsigned int cowonly:1;
68 /* 1 if no child node in the cache */
69 unsigned int lowest:1;
70 /* is the extent buffer locked */
71 unsigned int locked:1;
72 /* has the block been processed */
73 unsigned int processed:1;
74 /* have backrefs of this block been checked */
75 unsigned int checked:1;
76 /*
77 * 1 if corresponding block has been cowed but some upper
78 * level block pointers may not point to the new location
79 */
80 unsigned int pending:1;
81 /*
82 * 1 if the backref node isn't connected to any other
83 * backref node.
84 */
85 unsigned int detached:1;
86};
87
88/*
89 * present a block pointer in the backref cache
90 */
91struct backref_edge {
92 struct list_head list[2];
93 struct backref_node *node[2];
94};
95
96#define LOWER 0
97#define UPPER 1
98#define RELOCATION_RESERVED_NODES 256
99
100struct backref_cache {
101 /* red black tree of all backref nodes in the cache */
102 struct rb_root rb_root;
103 /* for passing backref nodes to btrfs_reloc_cow_block */
104 struct backref_node *path[BTRFS_MAX_LEVEL];
105 /*
106 * list of blocks that have been cowed but some block
107 * pointers in upper level blocks may not reflect the
108 * new location
109 */
110 struct list_head pending[BTRFS_MAX_LEVEL];
111 /* list of backref nodes with no child node */
112 struct list_head leaves;
113 /* list of blocks that have been cowed in current transaction */
114 struct list_head changed;
115 /* list of detached backref node. */
116 struct list_head detached;
117
118 u64 last_trans;
119
120 int nr_nodes;
121 int nr_edges;
122};
123
124/*
125 * map address of tree root to tree
126 */
127struct mapping_node {
128 struct rb_node rb_node;
129 u64 bytenr;
130 void *data;
131};
132
133struct mapping_tree {
134 struct rb_root rb_root;
135 spinlock_t lock;
136};
137
138/*
139 * present a tree block to process
140 */
141struct tree_block {
142 struct rb_node rb_node;
143 u64 bytenr;
144 struct btrfs_key key;
145 unsigned int level:8;
146 unsigned int key_ready:1;
147};
148
149#define MAX_EXTENTS 128
150
151struct file_extent_cluster {
152 u64 start;
153 u64 end;
154 u64 boundary[MAX_EXTENTS];
155 unsigned int nr;
156};
157
158struct reloc_control {
159 /* block group to relocate */
160 struct btrfs_block_group_cache *block_group;
161 /* extent tree */
162 struct btrfs_root *extent_root;
163 /* inode for moving data */
164 struct inode *data_inode;
165
166 struct btrfs_block_rsv *block_rsv;
167
168 struct backref_cache backref_cache;
169
170 struct file_extent_cluster cluster;
171 /* tree blocks have been processed */
172 struct extent_io_tree processed_blocks;
173 /* map start of tree root to corresponding reloc tree */
174 struct mapping_tree reloc_root_tree;
175 /* list of reloc trees */
176 struct list_head reloc_roots;
177 /* size of metadata reservation for merging reloc trees */
178 u64 merging_rsv_size;
179 /* size of relocated tree nodes */
180 u64 nodes_relocated;
181 /* reserved size for block group relocation*/
182 u64 reserved_bytes;
183
184 u64 search_start;
185 u64 extents_found;
186
187 unsigned int stage:8;
188 unsigned int create_reloc_tree:1;
189 unsigned int merge_reloc_tree:1;
190 unsigned int found_file_extent:1;
191};
192
193/* stages of data relocation */
194#define MOVE_DATA_EXTENTS 0
195#define UPDATE_DATA_PTRS 1
196
197static void remove_backref_node(struct backref_cache *cache,
198 struct backref_node *node);
199static void __mark_block_processed(struct reloc_control *rc,
200 struct backref_node *node);
201
202static void mapping_tree_init(struct mapping_tree *tree)
203{
204 tree->rb_root = RB_ROOT;
205 spin_lock_init(&tree->lock);
206}
207
208static void backref_cache_init(struct backref_cache *cache)
209{
210 int i;
211 cache->rb_root = RB_ROOT;
212 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
213 INIT_LIST_HEAD(&cache->pending[i]);
214 INIT_LIST_HEAD(&cache->changed);
215 INIT_LIST_HEAD(&cache->detached);
216 INIT_LIST_HEAD(&cache->leaves);
217}
218
219static void backref_cache_cleanup(struct backref_cache *cache)
220{
221 struct backref_node *node;
222 int i;
223
224 while (!list_empty(&cache->detached)) {
225 node = list_entry(cache->detached.next,
226 struct backref_node, list);
227 remove_backref_node(cache, node);
228 }
229
230 while (!list_empty(&cache->leaves)) {
231 node = list_entry(cache->leaves.next,
232 struct backref_node, lower);
233 remove_backref_node(cache, node);
234 }
235
236 cache->last_trans = 0;
237
238 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
239 ASSERT(list_empty(&cache->pending[i]));
240 ASSERT(list_empty(&cache->changed));
241 ASSERT(list_empty(&cache->detached));
242 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
243 ASSERT(!cache->nr_nodes);
244 ASSERT(!cache->nr_edges);
245}
246
247static struct backref_node *alloc_backref_node(struct backref_cache *cache)
248{
249 struct backref_node *node;
250
251 node = kzalloc(sizeof(*node), GFP_NOFS);
252 if (node) {
253 INIT_LIST_HEAD(&node->list);
254 INIT_LIST_HEAD(&node->upper);
255 INIT_LIST_HEAD(&node->lower);
256 RB_CLEAR_NODE(&node->rb_node);
257 cache->nr_nodes++;
258 }
259 return node;
260}
261
262static void free_backref_node(struct backref_cache *cache,
263 struct backref_node *node)
264{
265 if (node) {
266 cache->nr_nodes--;
267 kfree(node);
268 }
269}
270
271static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
272{
273 struct backref_edge *edge;
274
275 edge = kzalloc(sizeof(*edge), GFP_NOFS);
276 if (edge)
277 cache->nr_edges++;
278 return edge;
279}
280
281static void free_backref_edge(struct backref_cache *cache,
282 struct backref_edge *edge)
283{
284 if (edge) {
285 cache->nr_edges--;
286 kfree(edge);
287 }
288}
289
290static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
291 struct rb_node *node)
292{
293 struct rb_node **p = &root->rb_node;
294 struct rb_node *parent = NULL;
295 struct tree_entry *entry;
296
297 while (*p) {
298 parent = *p;
299 entry = rb_entry(parent, struct tree_entry, rb_node);
300
301 if (bytenr < entry->bytenr)
302 p = &(*p)->rb_left;
303 else if (bytenr > entry->bytenr)
304 p = &(*p)->rb_right;
305 else
306 return parent;
307 }
308
309 rb_link_node(node, parent, p);
310 rb_insert_color(node, root);
311 return NULL;
312}
313
314static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
315{
316 struct rb_node *n = root->rb_node;
317 struct tree_entry *entry;
318
319 while (n) {
320 entry = rb_entry(n, struct tree_entry, rb_node);
321
322 if (bytenr < entry->bytenr)
323 n = n->rb_left;
324 else if (bytenr > entry->bytenr)
325 n = n->rb_right;
326 else
327 return n;
328 }
329 return NULL;
330}
331
332static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
333{
334
335 struct btrfs_fs_info *fs_info = NULL;
336 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
337 rb_node);
338 if (bnode->root)
339 fs_info = bnode->root->fs_info;
340 btrfs_panic(fs_info, errno,
341 "Inconsistency in backref cache found at offset %llu",
342 bytenr);
343}
344
345/*
346 * walk up backref nodes until reach node presents tree root
347 */
348static struct backref_node *walk_up_backref(struct backref_node *node,
349 struct backref_edge *edges[],
350 int *index)
351{
352 struct backref_edge *edge;
353 int idx = *index;
354
355 while (!list_empty(&node->upper)) {
356 edge = list_entry(node->upper.next,
357 struct backref_edge, list[LOWER]);
358 edges[idx++] = edge;
359 node = edge->node[UPPER];
360 }
361 BUG_ON(node->detached);
362 *index = idx;
363 return node;
364}
365
366/*
367 * walk down backref nodes to find start of next reference path
368 */
369static struct backref_node *walk_down_backref(struct backref_edge *edges[],
370 int *index)
371{
372 struct backref_edge *edge;
373 struct backref_node *lower;
374 int idx = *index;
375
376 while (idx > 0) {
377 edge = edges[idx - 1];
378 lower = edge->node[LOWER];
379 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
380 idx--;
381 continue;
382 }
383 edge = list_entry(edge->list[LOWER].next,
384 struct backref_edge, list[LOWER]);
385 edges[idx - 1] = edge;
386 *index = idx;
387 return edge->node[UPPER];
388 }
389 *index = 0;
390 return NULL;
391}
392
393static void unlock_node_buffer(struct backref_node *node)
394{
395 if (node->locked) {
396 btrfs_tree_unlock(node->eb);
397 node->locked = 0;
398 }
399}
400
401static void drop_node_buffer(struct backref_node *node)
402{
403 if (node->eb) {
404 unlock_node_buffer(node);
405 free_extent_buffer(node->eb);
406 node->eb = NULL;
407 }
408}
409
410static void drop_backref_node(struct backref_cache *tree,
411 struct backref_node *node)
412{
413 BUG_ON(!list_empty(&node->upper));
414
415 drop_node_buffer(node);
416 list_del(&node->list);
417 list_del(&node->lower);
418 if (!RB_EMPTY_NODE(&node->rb_node))
419 rb_erase(&node->rb_node, &tree->rb_root);
420 free_backref_node(tree, node);
421}
422
423/*
424 * remove a backref node from the backref cache
425 */
426static void remove_backref_node(struct backref_cache *cache,
427 struct backref_node *node)
428{
429 struct backref_node *upper;
430 struct backref_edge *edge;
431
432 if (!node)
433 return;
434
435 BUG_ON(!node->lowest && !node->detached);
436 while (!list_empty(&node->upper)) {
437 edge = list_entry(node->upper.next, struct backref_edge,
438 list[LOWER]);
439 upper = edge->node[UPPER];
440 list_del(&edge->list[LOWER]);
441 list_del(&edge->list[UPPER]);
442 free_backref_edge(cache, edge);
443
444 if (RB_EMPTY_NODE(&upper->rb_node)) {
445 BUG_ON(!list_empty(&node->upper));
446 drop_backref_node(cache, node);
447 node = upper;
448 node->lowest = 1;
449 continue;
450 }
451 /*
452 * add the node to leaf node list if no other
453 * child block cached.
454 */
455 if (list_empty(&upper->lower)) {
456 list_add_tail(&upper->lower, &cache->leaves);
457 upper->lowest = 1;
458 }
459 }
460
461 drop_backref_node(cache, node);
462}
463
464static void update_backref_node(struct backref_cache *cache,
465 struct backref_node *node, u64 bytenr)
466{
467 struct rb_node *rb_node;
468 rb_erase(&node->rb_node, &cache->rb_root);
469 node->bytenr = bytenr;
470 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
471 if (rb_node)
472 backref_tree_panic(rb_node, -EEXIST, bytenr);
473}
474
475/*
476 * update backref cache after a transaction commit
477 */
478static int update_backref_cache(struct btrfs_trans_handle *trans,
479 struct backref_cache *cache)
480{
481 struct backref_node *node;
482 int level = 0;
483
484 if (cache->last_trans == 0) {
485 cache->last_trans = trans->transid;
486 return 0;
487 }
488
489 if (cache->last_trans == trans->transid)
490 return 0;
491
492 /*
493 * detached nodes are used to avoid unnecessary backref
494 * lookup. transaction commit changes the extent tree.
495 * so the detached nodes are no longer useful.
496 */
497 while (!list_empty(&cache->detached)) {
498 node = list_entry(cache->detached.next,
499 struct backref_node, list);
500 remove_backref_node(cache, node);
501 }
502
503 while (!list_empty(&cache->changed)) {
504 node = list_entry(cache->changed.next,
505 struct backref_node, list);
506 list_del_init(&node->list);
507 BUG_ON(node->pending);
508 update_backref_node(cache, node, node->new_bytenr);
509 }
510
511 /*
512 * some nodes can be left in the pending list if there were
513 * errors during processing the pending nodes.
514 */
515 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
516 list_for_each_entry(node, &cache->pending[level], list) {
517 BUG_ON(!node->pending);
518 if (node->bytenr == node->new_bytenr)
519 continue;
520 update_backref_node(cache, node, node->new_bytenr);
521 }
522 }
523
524 cache->last_trans = 0;
525 return 1;
526}
527
528
529static int should_ignore_root(struct btrfs_root *root)
530{
531 struct btrfs_root *reloc_root;
532
533 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
534 return 0;
535
536 reloc_root = root->reloc_root;
537 if (!reloc_root)
538 return 0;
539
540 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
541 root->fs_info->running_transaction->transid - 1)
542 return 0;
543 /*
544 * if there is reloc tree and it was created in previous
545 * transaction backref lookup can find the reloc tree,
546 * so backref node for the fs tree root is useless for
547 * relocation.
548 */
549 return 1;
550}
551/*
552 * find reloc tree by address of tree root
553 */
554static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
555 u64 bytenr)
556{
557 struct rb_node *rb_node;
558 struct mapping_node *node;
559 struct btrfs_root *root = NULL;
560
561 spin_lock(&rc->reloc_root_tree.lock);
562 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
563 if (rb_node) {
564 node = rb_entry(rb_node, struct mapping_node, rb_node);
565 root = (struct btrfs_root *)node->data;
566 }
567 spin_unlock(&rc->reloc_root_tree.lock);
568 return root;
569}
570
571static int is_cowonly_root(u64 root_objectid)
572{
573 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
574 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
575 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
576 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
577 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
578 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
579 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
580 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
581 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
582 return 1;
583 return 0;
584}
585
586static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
587 u64 root_objectid)
588{
589 struct btrfs_key key;
590
591 key.objectid = root_objectid;
592 key.type = BTRFS_ROOT_ITEM_KEY;
593 if (is_cowonly_root(root_objectid))
594 key.offset = 0;
595 else
596 key.offset = (u64)-1;
597
598 return btrfs_get_fs_root(fs_info, &key, false);
599}
600
601#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
602static noinline_for_stack
603struct btrfs_root *find_tree_root(struct reloc_control *rc,
604 struct extent_buffer *leaf,
605 struct btrfs_extent_ref_v0 *ref0)
606{
607 struct btrfs_root *root;
608 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
609 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
610
611 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
612
613 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
614 BUG_ON(IS_ERR(root));
615
616 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
617 generation != btrfs_root_generation(&root->root_item))
618 return NULL;
619
620 return root;
621}
622#endif
623
624static noinline_for_stack
625int find_inline_backref(struct extent_buffer *leaf, int slot,
626 unsigned long *ptr, unsigned long *end)
627{
628 struct btrfs_key key;
629 struct btrfs_extent_item *ei;
630 struct btrfs_tree_block_info *bi;
631 u32 item_size;
632
633 btrfs_item_key_to_cpu(leaf, &key, slot);
634
635 item_size = btrfs_item_size_nr(leaf, slot);
636#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
637 if (item_size < sizeof(*ei)) {
638 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
639 return 1;
640 }
641#endif
642 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
643 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
644 BTRFS_EXTENT_FLAG_TREE_BLOCK));
645
646 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
647 item_size <= sizeof(*ei) + sizeof(*bi)) {
648 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
649 return 1;
650 }
651 if (key.type == BTRFS_METADATA_ITEM_KEY &&
652 item_size <= sizeof(*ei)) {
653 WARN_ON(item_size < sizeof(*ei));
654 return 1;
655 }
656
657 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
658 bi = (struct btrfs_tree_block_info *)(ei + 1);
659 *ptr = (unsigned long)(bi + 1);
660 } else {
661 *ptr = (unsigned long)(ei + 1);
662 }
663 *end = (unsigned long)ei + item_size;
664 return 0;
665}
666
667/*
668 * build backref tree for a given tree block. root of the backref tree
669 * corresponds the tree block, leaves of the backref tree correspond
670 * roots of b-trees that reference the tree block.
671 *
672 * the basic idea of this function is check backrefs of a given block
673 * to find upper level blocks that reference the block, and then check
674 * backrefs of these upper level blocks recursively. the recursion stop
675 * when tree root is reached or backrefs for the block is cached.
676 *
677 * NOTE: if we find backrefs for a block are cached, we know backrefs
678 * for all upper level blocks that directly/indirectly reference the
679 * block are also cached.
680 */
681static noinline_for_stack
682struct backref_node *build_backref_tree(struct reloc_control *rc,
683 struct btrfs_key *node_key,
684 int level, u64 bytenr)
685{
686 struct backref_cache *cache = &rc->backref_cache;
687 struct btrfs_path *path1;
688 struct btrfs_path *path2;
689 struct extent_buffer *eb;
690 struct btrfs_root *root;
691 struct backref_node *cur;
692 struct backref_node *upper;
693 struct backref_node *lower;
694 struct backref_node *node = NULL;
695 struct backref_node *exist = NULL;
696 struct backref_edge *edge;
697 struct rb_node *rb_node;
698 struct btrfs_key key;
699 unsigned long end;
700 unsigned long ptr;
701 LIST_HEAD(list);
702 LIST_HEAD(useless);
703 int cowonly;
704 int ret;
705 int err = 0;
706 bool need_check = true;
707
708 path1 = btrfs_alloc_path();
709 path2 = btrfs_alloc_path();
710 if (!path1 || !path2) {
711 err = -ENOMEM;
712 goto out;
713 }
714 path1->reada = READA_FORWARD;
715 path2->reada = READA_FORWARD;
716
717 node = alloc_backref_node(cache);
718 if (!node) {
719 err = -ENOMEM;
720 goto out;
721 }
722
723 node->bytenr = bytenr;
724 node->level = level;
725 node->lowest = 1;
726 cur = node;
727again:
728 end = 0;
729 ptr = 0;
730 key.objectid = cur->bytenr;
731 key.type = BTRFS_METADATA_ITEM_KEY;
732 key.offset = (u64)-1;
733
734 path1->search_commit_root = 1;
735 path1->skip_locking = 1;
736 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
737 0, 0);
738 if (ret < 0) {
739 err = ret;
740 goto out;
741 }
742 ASSERT(ret);
743 ASSERT(path1->slots[0]);
744
745 path1->slots[0]--;
746
747 WARN_ON(cur->checked);
748 if (!list_empty(&cur->upper)) {
749 /*
750 * the backref was added previously when processing
751 * backref of type BTRFS_TREE_BLOCK_REF_KEY
752 */
753 ASSERT(list_is_singular(&cur->upper));
754 edge = list_entry(cur->upper.next, struct backref_edge,
755 list[LOWER]);
756 ASSERT(list_empty(&edge->list[UPPER]));
757 exist = edge->node[UPPER];
758 /*
759 * add the upper level block to pending list if we need
760 * check its backrefs
761 */
762 if (!exist->checked)
763 list_add_tail(&edge->list[UPPER], &list);
764 } else {
765 exist = NULL;
766 }
767
768 while (1) {
769 cond_resched();
770 eb = path1->nodes[0];
771
772 if (ptr >= end) {
773 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
774 ret = btrfs_next_leaf(rc->extent_root, path1);
775 if (ret < 0) {
776 err = ret;
777 goto out;
778 }
779 if (ret > 0)
780 break;
781 eb = path1->nodes[0];
782 }
783
784 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
785 if (key.objectid != cur->bytenr) {
786 WARN_ON(exist);
787 break;
788 }
789
790 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
791 key.type == BTRFS_METADATA_ITEM_KEY) {
792 ret = find_inline_backref(eb, path1->slots[0],
793 &ptr, &end);
794 if (ret)
795 goto next;
796 }
797 }
798
799 if (ptr < end) {
800 /* update key for inline back ref */
801 struct btrfs_extent_inline_ref *iref;
802 iref = (struct btrfs_extent_inline_ref *)ptr;
803 key.type = btrfs_extent_inline_ref_type(eb, iref);
804 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
805 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
806 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
807 }
808
809 if (exist &&
810 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
811 exist->owner == key.offset) ||
812 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
813 exist->bytenr == key.offset))) {
814 exist = NULL;
815 goto next;
816 }
817
818#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
819 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
820 key.type == BTRFS_EXTENT_REF_V0_KEY) {
821 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
822 struct btrfs_extent_ref_v0 *ref0;
823 ref0 = btrfs_item_ptr(eb, path1->slots[0],
824 struct btrfs_extent_ref_v0);
825 if (key.objectid == key.offset) {
826 root = find_tree_root(rc, eb, ref0);
827 if (root && !should_ignore_root(root))
828 cur->root = root;
829 else
830 list_add(&cur->list, &useless);
831 break;
832 }
833 if (is_cowonly_root(btrfs_ref_root_v0(eb,
834 ref0)))
835 cur->cowonly = 1;
836 }
837#else
838 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
839 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
840#endif
841 if (key.objectid == key.offset) {
842 /*
843 * only root blocks of reloc trees use
844 * backref of this type.
845 */
846 root = find_reloc_root(rc, cur->bytenr);
847 ASSERT(root);
848 cur->root = root;
849 break;
850 }
851
852 edge = alloc_backref_edge(cache);
853 if (!edge) {
854 err = -ENOMEM;
855 goto out;
856 }
857 rb_node = tree_search(&cache->rb_root, key.offset);
858 if (!rb_node) {
859 upper = alloc_backref_node(cache);
860 if (!upper) {
861 free_backref_edge(cache, edge);
862 err = -ENOMEM;
863 goto out;
864 }
865 upper->bytenr = key.offset;
866 upper->level = cur->level + 1;
867 /*
868 * backrefs for the upper level block isn't
869 * cached, add the block to pending list
870 */
871 list_add_tail(&edge->list[UPPER], &list);
872 } else {
873 upper = rb_entry(rb_node, struct backref_node,
874 rb_node);
875 ASSERT(upper->checked);
876 INIT_LIST_HEAD(&edge->list[UPPER]);
877 }
878 list_add_tail(&edge->list[LOWER], &cur->upper);
879 edge->node[LOWER] = cur;
880 edge->node[UPPER] = upper;
881
882 goto next;
883 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
884 goto next;
885 }
886
887 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
888 root = read_fs_root(rc->extent_root->fs_info, key.offset);
889 if (IS_ERR(root)) {
890 err = PTR_ERR(root);
891 goto out;
892 }
893
894 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
895 cur->cowonly = 1;
896
897 if (btrfs_root_level(&root->root_item) == cur->level) {
898 /* tree root */
899 ASSERT(btrfs_root_bytenr(&root->root_item) ==
900 cur->bytenr);
901 if (should_ignore_root(root))
902 list_add(&cur->list, &useless);
903 else
904 cur->root = root;
905 break;
906 }
907
908 level = cur->level + 1;
909
910 /*
911 * searching the tree to find upper level blocks
912 * reference the block.
913 */
914 path2->search_commit_root = 1;
915 path2->skip_locking = 1;
916 path2->lowest_level = level;
917 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
918 path2->lowest_level = 0;
919 if (ret < 0) {
920 err = ret;
921 goto out;
922 }
923 if (ret > 0 && path2->slots[level] > 0)
924 path2->slots[level]--;
925
926 eb = path2->nodes[level];
927 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
928 cur->bytenr) {
929 btrfs_err(root->fs_info,
930 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
931 cur->bytenr, level - 1, root->objectid,
932 node_key->objectid, node_key->type,
933 node_key->offset);
934 err = -ENOENT;
935 goto out;
936 }
937 lower = cur;
938 need_check = true;
939 for (; level < BTRFS_MAX_LEVEL; level++) {
940 if (!path2->nodes[level]) {
941 ASSERT(btrfs_root_bytenr(&root->root_item) ==
942 lower->bytenr);
943 if (should_ignore_root(root))
944 list_add(&lower->list, &useless);
945 else
946 lower->root = root;
947 break;
948 }
949
950 edge = alloc_backref_edge(cache);
951 if (!edge) {
952 err = -ENOMEM;
953 goto out;
954 }
955
956 eb = path2->nodes[level];
957 rb_node = tree_search(&cache->rb_root, eb->start);
958 if (!rb_node) {
959 upper = alloc_backref_node(cache);
960 if (!upper) {
961 free_backref_edge(cache, edge);
962 err = -ENOMEM;
963 goto out;
964 }
965 upper->bytenr = eb->start;
966 upper->owner = btrfs_header_owner(eb);
967 upper->level = lower->level + 1;
968 if (!test_bit(BTRFS_ROOT_REF_COWS,
969 &root->state))
970 upper->cowonly = 1;
971
972 /*
973 * if we know the block isn't shared
974 * we can void checking its backrefs.
975 */
976 if (btrfs_block_can_be_shared(root, eb))
977 upper->checked = 0;
978 else
979 upper->checked = 1;
980
981 /*
982 * add the block to pending list if we
983 * need check its backrefs, we only do this once
984 * while walking up a tree as we will catch
985 * anything else later on.
986 */
987 if (!upper->checked && need_check) {
988 need_check = false;
989 list_add_tail(&edge->list[UPPER],
990 &list);
991 } else {
992 if (upper->checked)
993 need_check = true;
994 INIT_LIST_HEAD(&edge->list[UPPER]);
995 }
996 } else {
997 upper = rb_entry(rb_node, struct backref_node,
998 rb_node);
999 ASSERT(upper->checked);
1000 INIT_LIST_HEAD(&edge->list[UPPER]);
1001 if (!upper->owner)
1002 upper->owner = btrfs_header_owner(eb);
1003 }
1004 list_add_tail(&edge->list[LOWER], &lower->upper);
1005 edge->node[LOWER] = lower;
1006 edge->node[UPPER] = upper;
1007
1008 if (rb_node)
1009 break;
1010 lower = upper;
1011 upper = NULL;
1012 }
1013 btrfs_release_path(path2);
1014next:
1015 if (ptr < end) {
1016 ptr += btrfs_extent_inline_ref_size(key.type);
1017 if (ptr >= end) {
1018 WARN_ON(ptr > end);
1019 ptr = 0;
1020 end = 0;
1021 }
1022 }
1023 if (ptr >= end)
1024 path1->slots[0]++;
1025 }
1026 btrfs_release_path(path1);
1027
1028 cur->checked = 1;
1029 WARN_ON(exist);
1030
1031 /* the pending list isn't empty, take the first block to process */
1032 if (!list_empty(&list)) {
1033 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1034 list_del_init(&edge->list[UPPER]);
1035 cur = edge->node[UPPER];
1036 goto again;
1037 }
1038
1039 /*
1040 * everything goes well, connect backref nodes and insert backref nodes
1041 * into the cache.
1042 */
1043 ASSERT(node->checked);
1044 cowonly = node->cowonly;
1045 if (!cowonly) {
1046 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1047 &node->rb_node);
1048 if (rb_node)
1049 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1050 list_add_tail(&node->lower, &cache->leaves);
1051 }
1052
1053 list_for_each_entry(edge, &node->upper, list[LOWER])
1054 list_add_tail(&edge->list[UPPER], &list);
1055
1056 while (!list_empty(&list)) {
1057 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1058 list_del_init(&edge->list[UPPER]);
1059 upper = edge->node[UPPER];
1060 if (upper->detached) {
1061 list_del(&edge->list[LOWER]);
1062 lower = edge->node[LOWER];
1063 free_backref_edge(cache, edge);
1064 if (list_empty(&lower->upper))
1065 list_add(&lower->list, &useless);
1066 continue;
1067 }
1068
1069 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1070 if (upper->lowest) {
1071 list_del_init(&upper->lower);
1072 upper->lowest = 0;
1073 }
1074
1075 list_add_tail(&edge->list[UPPER], &upper->lower);
1076 continue;
1077 }
1078
1079 if (!upper->checked) {
1080 /*
1081 * Still want to blow up for developers since this is a
1082 * logic bug.
1083 */
1084 ASSERT(0);
1085 err = -EINVAL;
1086 goto out;
1087 }
1088 if (cowonly != upper->cowonly) {
1089 ASSERT(0);
1090 err = -EINVAL;
1091 goto out;
1092 }
1093
1094 if (!cowonly) {
1095 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1096 &upper->rb_node);
1097 if (rb_node)
1098 backref_tree_panic(rb_node, -EEXIST,
1099 upper->bytenr);
1100 }
1101
1102 list_add_tail(&edge->list[UPPER], &upper->lower);
1103
1104 list_for_each_entry(edge, &upper->upper, list[LOWER])
1105 list_add_tail(&edge->list[UPPER], &list);
1106 }
1107 /*
1108 * process useless backref nodes. backref nodes for tree leaves
1109 * are deleted from the cache. backref nodes for upper level
1110 * tree blocks are left in the cache to avoid unnecessary backref
1111 * lookup.
1112 */
1113 while (!list_empty(&useless)) {
1114 upper = list_entry(useless.next, struct backref_node, list);
1115 list_del_init(&upper->list);
1116 ASSERT(list_empty(&upper->upper));
1117 if (upper == node)
1118 node = NULL;
1119 if (upper->lowest) {
1120 list_del_init(&upper->lower);
1121 upper->lowest = 0;
1122 }
1123 while (!list_empty(&upper->lower)) {
1124 edge = list_entry(upper->lower.next,
1125 struct backref_edge, list[UPPER]);
1126 list_del(&edge->list[UPPER]);
1127 list_del(&edge->list[LOWER]);
1128 lower = edge->node[LOWER];
1129 free_backref_edge(cache, edge);
1130
1131 if (list_empty(&lower->upper))
1132 list_add(&lower->list, &useless);
1133 }
1134 __mark_block_processed(rc, upper);
1135 if (upper->level > 0) {
1136 list_add(&upper->list, &cache->detached);
1137 upper->detached = 1;
1138 } else {
1139 rb_erase(&upper->rb_node, &cache->rb_root);
1140 free_backref_node(cache, upper);
1141 }
1142 }
1143out:
1144 btrfs_free_path(path1);
1145 btrfs_free_path(path2);
1146 if (err) {
1147 while (!list_empty(&useless)) {
1148 lower = list_entry(useless.next,
1149 struct backref_node, list);
1150 list_del_init(&lower->list);
1151 }
1152 while (!list_empty(&list)) {
1153 edge = list_first_entry(&list, struct backref_edge,
1154 list[UPPER]);
1155 list_del(&edge->list[UPPER]);
1156 list_del(&edge->list[LOWER]);
1157 lower = edge->node[LOWER];
1158 upper = edge->node[UPPER];
1159 free_backref_edge(cache, edge);
1160
1161 /*
1162 * Lower is no longer linked to any upper backref nodes
1163 * and isn't in the cache, we can free it ourselves.
1164 */
1165 if (list_empty(&lower->upper) &&
1166 RB_EMPTY_NODE(&lower->rb_node))
1167 list_add(&lower->list, &useless);
1168
1169 if (!RB_EMPTY_NODE(&upper->rb_node))
1170 continue;
1171
1172 /* Add this guy's upper edges to the list to process */
1173 list_for_each_entry(edge, &upper->upper, list[LOWER])
1174 list_add_tail(&edge->list[UPPER], &list);
1175 if (list_empty(&upper->upper))
1176 list_add(&upper->list, &useless);
1177 }
1178
1179 while (!list_empty(&useless)) {
1180 lower = list_entry(useless.next,
1181 struct backref_node, list);
1182 list_del_init(&lower->list);
1183 if (lower == node)
1184 node = NULL;
1185 free_backref_node(cache, lower);
1186 }
1187
1188 free_backref_node(cache, node);
1189 return ERR_PTR(err);
1190 }
1191 ASSERT(!node || !node->detached);
1192 return node;
1193}
1194
1195/*
1196 * helper to add backref node for the newly created snapshot.
1197 * the backref node is created by cloning backref node that
1198 * corresponds to root of source tree
1199 */
1200static int clone_backref_node(struct btrfs_trans_handle *trans,
1201 struct reloc_control *rc,
1202 struct btrfs_root *src,
1203 struct btrfs_root *dest)
1204{
1205 struct btrfs_root *reloc_root = src->reloc_root;
1206 struct backref_cache *cache = &rc->backref_cache;
1207 struct backref_node *node = NULL;
1208 struct backref_node *new_node;
1209 struct backref_edge *edge;
1210 struct backref_edge *new_edge;
1211 struct rb_node *rb_node;
1212
1213 if (cache->last_trans > 0)
1214 update_backref_cache(trans, cache);
1215
1216 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1217 if (rb_node) {
1218 node = rb_entry(rb_node, struct backref_node, rb_node);
1219 if (node->detached)
1220 node = NULL;
1221 else
1222 BUG_ON(node->new_bytenr != reloc_root->node->start);
1223 }
1224
1225 if (!node) {
1226 rb_node = tree_search(&cache->rb_root,
1227 reloc_root->commit_root->start);
1228 if (rb_node) {
1229 node = rb_entry(rb_node, struct backref_node,
1230 rb_node);
1231 BUG_ON(node->detached);
1232 }
1233 }
1234
1235 if (!node)
1236 return 0;
1237
1238 new_node = alloc_backref_node(cache);
1239 if (!new_node)
1240 return -ENOMEM;
1241
1242 new_node->bytenr = dest->node->start;
1243 new_node->level = node->level;
1244 new_node->lowest = node->lowest;
1245 new_node->checked = 1;
1246 new_node->root = dest;
1247
1248 if (!node->lowest) {
1249 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1250 new_edge = alloc_backref_edge(cache);
1251 if (!new_edge)
1252 goto fail;
1253
1254 new_edge->node[UPPER] = new_node;
1255 new_edge->node[LOWER] = edge->node[LOWER];
1256 list_add_tail(&new_edge->list[UPPER],
1257 &new_node->lower);
1258 }
1259 } else {
1260 list_add_tail(&new_node->lower, &cache->leaves);
1261 }
1262
1263 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1264 &new_node->rb_node);
1265 if (rb_node)
1266 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1267
1268 if (!new_node->lowest) {
1269 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1270 list_add_tail(&new_edge->list[LOWER],
1271 &new_edge->node[LOWER]->upper);
1272 }
1273 }
1274 return 0;
1275fail:
1276 while (!list_empty(&new_node->lower)) {
1277 new_edge = list_entry(new_node->lower.next,
1278 struct backref_edge, list[UPPER]);
1279 list_del(&new_edge->list[UPPER]);
1280 free_backref_edge(cache, new_edge);
1281 }
1282 free_backref_node(cache, new_node);
1283 return -ENOMEM;
1284}
1285
1286/*
1287 * helper to add 'address of tree root -> reloc tree' mapping
1288 */
1289static int __must_check __add_reloc_root(struct btrfs_root *root)
1290{
1291 struct btrfs_fs_info *fs_info = root->fs_info;
1292 struct rb_node *rb_node;
1293 struct mapping_node *node;
1294 struct reloc_control *rc = fs_info->reloc_ctl;
1295
1296 node = kmalloc(sizeof(*node), GFP_NOFS);
1297 if (!node)
1298 return -ENOMEM;
1299
1300 node->bytenr = root->node->start;
1301 node->data = root;
1302
1303 spin_lock(&rc->reloc_root_tree.lock);
1304 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1305 node->bytenr, &node->rb_node);
1306 spin_unlock(&rc->reloc_root_tree.lock);
1307 if (rb_node) {
1308 btrfs_panic(fs_info, -EEXIST,
1309 "Duplicate root found for start=%llu while inserting into relocation tree",
1310 node->bytenr);
1311 kfree(node);
1312 return -EEXIST;
1313 }
1314
1315 list_add_tail(&root->root_list, &rc->reloc_roots);
1316 return 0;
1317}
1318
1319/*
1320 * helper to delete the 'address of tree root -> reloc tree'
1321 * mapping
1322 */
1323static void __del_reloc_root(struct btrfs_root *root)
1324{
1325 struct btrfs_fs_info *fs_info = root->fs_info;
1326 struct rb_node *rb_node;
1327 struct mapping_node *node = NULL;
1328 struct reloc_control *rc = fs_info->reloc_ctl;
1329
1330 spin_lock(&rc->reloc_root_tree.lock);
1331 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1332 root->node->start);
1333 if (rb_node) {
1334 node = rb_entry(rb_node, struct mapping_node, rb_node);
1335 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1336 }
1337 spin_unlock(&rc->reloc_root_tree.lock);
1338
1339 if (!node)
1340 return;
1341 BUG_ON((struct btrfs_root *)node->data != root);
1342
1343 spin_lock(&fs_info->trans_lock);
1344 list_del_init(&root->root_list);
1345 spin_unlock(&fs_info->trans_lock);
1346 kfree(node);
1347}
1348
1349/*
1350 * helper to update the 'address of tree root -> reloc tree'
1351 * mapping
1352 */
1353static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1354{
1355 struct btrfs_fs_info *fs_info = root->fs_info;
1356 struct rb_node *rb_node;
1357 struct mapping_node *node = NULL;
1358 struct reloc_control *rc = fs_info->reloc_ctl;
1359
1360 spin_lock(&rc->reloc_root_tree.lock);
1361 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1362 root->node->start);
1363 if (rb_node) {
1364 node = rb_entry(rb_node, struct mapping_node, rb_node);
1365 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1366 }
1367 spin_unlock(&rc->reloc_root_tree.lock);
1368
1369 if (!node)
1370 return 0;
1371 BUG_ON((struct btrfs_root *)node->data != root);
1372
1373 spin_lock(&rc->reloc_root_tree.lock);
1374 node->bytenr = new_bytenr;
1375 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1376 node->bytenr, &node->rb_node);
1377 spin_unlock(&rc->reloc_root_tree.lock);
1378 if (rb_node)
1379 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1380 return 0;
1381}
1382
1383static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1384 struct btrfs_root *root, u64 objectid)
1385{
1386 struct btrfs_fs_info *fs_info = root->fs_info;
1387 struct btrfs_root *reloc_root;
1388 struct extent_buffer *eb;
1389 struct btrfs_root_item *root_item;
1390 struct btrfs_key root_key;
1391 int ret;
1392
1393 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1394 BUG_ON(!root_item);
1395
1396 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1397 root_key.type = BTRFS_ROOT_ITEM_KEY;
1398 root_key.offset = objectid;
1399
1400 if (root->root_key.objectid == objectid) {
1401 u64 commit_root_gen;
1402
1403 /* called by btrfs_init_reloc_root */
1404 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1405 BTRFS_TREE_RELOC_OBJECTID);
1406 BUG_ON(ret);
1407 /*
1408 * Set the last_snapshot field to the generation of the commit
1409 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1410 * correctly (returns true) when the relocation root is created
1411 * either inside the critical section of a transaction commit
1412 * (through transaction.c:qgroup_account_snapshot()) and when
1413 * it's created before the transaction commit is started.
1414 */
1415 commit_root_gen = btrfs_header_generation(root->commit_root);
1416 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1417 } else {
1418 /*
1419 * called by btrfs_reloc_post_snapshot_hook.
1420 * the source tree is a reloc tree, all tree blocks
1421 * modified after it was created have RELOC flag
1422 * set in their headers. so it's OK to not update
1423 * the 'last_snapshot'.
1424 */
1425 ret = btrfs_copy_root(trans, root, root->node, &eb,
1426 BTRFS_TREE_RELOC_OBJECTID);
1427 BUG_ON(ret);
1428 }
1429
1430 memcpy(root_item, &root->root_item, sizeof(*root_item));
1431 btrfs_set_root_bytenr(root_item, eb->start);
1432 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1433 btrfs_set_root_generation(root_item, trans->transid);
1434
1435 if (root->root_key.objectid == objectid) {
1436 btrfs_set_root_refs(root_item, 0);
1437 memset(&root_item->drop_progress, 0,
1438 sizeof(struct btrfs_disk_key));
1439 root_item->drop_level = 0;
1440 }
1441
1442 btrfs_tree_unlock(eb);
1443 free_extent_buffer(eb);
1444
1445 ret = btrfs_insert_root(trans, fs_info->tree_root,
1446 &root_key, root_item);
1447 BUG_ON(ret);
1448 kfree(root_item);
1449
1450 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1451 BUG_ON(IS_ERR(reloc_root));
1452 reloc_root->last_trans = trans->transid;
1453 return reloc_root;
1454}
1455
1456/*
1457 * create reloc tree for a given fs tree. reloc tree is just a
1458 * snapshot of the fs tree with special root objectid.
1459 */
1460int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1461 struct btrfs_root *root)
1462{
1463 struct btrfs_fs_info *fs_info = root->fs_info;
1464 struct btrfs_root *reloc_root;
1465 struct reloc_control *rc = fs_info->reloc_ctl;
1466 struct btrfs_block_rsv *rsv;
1467 int clear_rsv = 0;
1468 int ret;
1469
1470 if (root->reloc_root) {
1471 reloc_root = root->reloc_root;
1472 reloc_root->last_trans = trans->transid;
1473 return 0;
1474 }
1475
1476 if (!rc || !rc->create_reloc_tree ||
1477 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1478 return 0;
1479
1480 if (!trans->reloc_reserved) {
1481 rsv = trans->block_rsv;
1482 trans->block_rsv = rc->block_rsv;
1483 clear_rsv = 1;
1484 }
1485 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1486 if (clear_rsv)
1487 trans->block_rsv = rsv;
1488
1489 ret = __add_reloc_root(reloc_root);
1490 BUG_ON(ret < 0);
1491 root->reloc_root = reloc_root;
1492 return 0;
1493}
1494
1495/*
1496 * update root item of reloc tree
1497 */
1498int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1499 struct btrfs_root *root)
1500{
1501 struct btrfs_fs_info *fs_info = root->fs_info;
1502 struct btrfs_root *reloc_root;
1503 struct btrfs_root_item *root_item;
1504 int ret;
1505
1506 if (!root->reloc_root)
1507 goto out;
1508
1509 reloc_root = root->reloc_root;
1510 root_item = &reloc_root->root_item;
1511
1512 if (fs_info->reloc_ctl->merge_reloc_tree &&
1513 btrfs_root_refs(root_item) == 0) {
1514 root->reloc_root = NULL;
1515 __del_reloc_root(reloc_root);
1516 }
1517
1518 if (reloc_root->commit_root != reloc_root->node) {
1519 btrfs_set_root_node(root_item, reloc_root->node);
1520 free_extent_buffer(reloc_root->commit_root);
1521 reloc_root->commit_root = btrfs_root_node(reloc_root);
1522 }
1523
1524 ret = btrfs_update_root(trans, fs_info->tree_root,
1525 &reloc_root->root_key, root_item);
1526 BUG_ON(ret);
1527
1528out:
1529 return 0;
1530}
1531
1532/*
1533 * helper to find first cached inode with inode number >= objectid
1534 * in a subvolume
1535 */
1536static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1537{
1538 struct rb_node *node;
1539 struct rb_node *prev;
1540 struct btrfs_inode *entry;
1541 struct inode *inode;
1542
1543 spin_lock(&root->inode_lock);
1544again:
1545 node = root->inode_tree.rb_node;
1546 prev = NULL;
1547 while (node) {
1548 prev = node;
1549 entry = rb_entry(node, struct btrfs_inode, rb_node);
1550
1551 if (objectid < btrfs_ino(&entry->vfs_inode))
1552 node = node->rb_left;
1553 else if (objectid > btrfs_ino(&entry->vfs_inode))
1554 node = node->rb_right;
1555 else
1556 break;
1557 }
1558 if (!node) {
1559 while (prev) {
1560 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1561 if (objectid <= btrfs_ino(&entry->vfs_inode)) {
1562 node = prev;
1563 break;
1564 }
1565 prev = rb_next(prev);
1566 }
1567 }
1568 while (node) {
1569 entry = rb_entry(node, struct btrfs_inode, rb_node);
1570 inode = igrab(&entry->vfs_inode);
1571 if (inode) {
1572 spin_unlock(&root->inode_lock);
1573 return inode;
1574 }
1575
1576 objectid = btrfs_ino(&entry->vfs_inode) + 1;
1577 if (cond_resched_lock(&root->inode_lock))
1578 goto again;
1579
1580 node = rb_next(node);
1581 }
1582 spin_unlock(&root->inode_lock);
1583 return NULL;
1584}
1585
1586static int in_block_group(u64 bytenr,
1587 struct btrfs_block_group_cache *block_group)
1588{
1589 if (bytenr >= block_group->key.objectid &&
1590 bytenr < block_group->key.objectid + block_group->key.offset)
1591 return 1;
1592 return 0;
1593}
1594
1595/*
1596 * get new location of data
1597 */
1598static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1599 u64 bytenr, u64 num_bytes)
1600{
1601 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1602 struct btrfs_path *path;
1603 struct btrfs_file_extent_item *fi;
1604 struct extent_buffer *leaf;
1605 int ret;
1606
1607 path = btrfs_alloc_path();
1608 if (!path)
1609 return -ENOMEM;
1610
1611 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1612 ret = btrfs_lookup_file_extent(NULL, root, path, btrfs_ino(reloc_inode),
1613 bytenr, 0);
1614 if (ret < 0)
1615 goto out;
1616 if (ret > 0) {
1617 ret = -ENOENT;
1618 goto out;
1619 }
1620
1621 leaf = path->nodes[0];
1622 fi = btrfs_item_ptr(leaf, path->slots[0],
1623 struct btrfs_file_extent_item);
1624
1625 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1626 btrfs_file_extent_compression(leaf, fi) ||
1627 btrfs_file_extent_encryption(leaf, fi) ||
1628 btrfs_file_extent_other_encoding(leaf, fi));
1629
1630 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1631 ret = -EINVAL;
1632 goto out;
1633 }
1634
1635 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1636 ret = 0;
1637out:
1638 btrfs_free_path(path);
1639 return ret;
1640}
1641
1642/*
1643 * update file extent items in the tree leaf to point to
1644 * the new locations.
1645 */
1646static noinline_for_stack
1647int replace_file_extents(struct btrfs_trans_handle *trans,
1648 struct reloc_control *rc,
1649 struct btrfs_root *root,
1650 struct extent_buffer *leaf)
1651{
1652 struct btrfs_fs_info *fs_info = root->fs_info;
1653 struct btrfs_key key;
1654 struct btrfs_file_extent_item *fi;
1655 struct inode *inode = NULL;
1656 u64 parent;
1657 u64 bytenr;
1658 u64 new_bytenr = 0;
1659 u64 num_bytes;
1660 u64 end;
1661 u32 nritems;
1662 u32 i;
1663 int ret = 0;
1664 int first = 1;
1665 int dirty = 0;
1666
1667 if (rc->stage != UPDATE_DATA_PTRS)
1668 return 0;
1669
1670 /* reloc trees always use full backref */
1671 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1672 parent = leaf->start;
1673 else
1674 parent = 0;
1675
1676 nritems = btrfs_header_nritems(leaf);
1677 for (i = 0; i < nritems; i++) {
1678 cond_resched();
1679 btrfs_item_key_to_cpu(leaf, &key, i);
1680 if (key.type != BTRFS_EXTENT_DATA_KEY)
1681 continue;
1682 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1683 if (btrfs_file_extent_type(leaf, fi) ==
1684 BTRFS_FILE_EXTENT_INLINE)
1685 continue;
1686 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1687 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1688 if (bytenr == 0)
1689 continue;
1690 if (!in_block_group(bytenr, rc->block_group))
1691 continue;
1692
1693 /*
1694 * if we are modifying block in fs tree, wait for readpage
1695 * to complete and drop the extent cache
1696 */
1697 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1698 if (first) {
1699 inode = find_next_inode(root, key.objectid);
1700 first = 0;
1701 } else if (inode && btrfs_ino(inode) < key.objectid) {
1702 btrfs_add_delayed_iput(inode);
1703 inode = find_next_inode(root, key.objectid);
1704 }
1705 if (inode && btrfs_ino(inode) == key.objectid) {
1706 end = key.offset +
1707 btrfs_file_extent_num_bytes(leaf, fi);
1708 WARN_ON(!IS_ALIGNED(key.offset,
1709 fs_info->sectorsize));
1710 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1711 end--;
1712 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1713 key.offset, end);
1714 if (!ret)
1715 continue;
1716
1717 btrfs_drop_extent_cache(inode, key.offset, end,
1718 1);
1719 unlock_extent(&BTRFS_I(inode)->io_tree,
1720 key.offset, end);
1721 }
1722 }
1723
1724 ret = get_new_location(rc->data_inode, &new_bytenr,
1725 bytenr, num_bytes);
1726 if (ret) {
1727 /*
1728 * Don't have to abort since we've not changed anything
1729 * in the file extent yet.
1730 */
1731 break;
1732 }
1733
1734 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1735 dirty = 1;
1736
1737 key.offset -= btrfs_file_extent_offset(leaf, fi);
1738 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1739 num_bytes, parent,
1740 btrfs_header_owner(leaf),
1741 key.objectid, key.offset);
1742 if (ret) {
1743 btrfs_abort_transaction(trans, ret);
1744 break;
1745 }
1746
1747 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1748 parent, btrfs_header_owner(leaf),
1749 key.objectid, key.offset);
1750 if (ret) {
1751 btrfs_abort_transaction(trans, ret);
1752 break;
1753 }
1754 }
1755 if (dirty)
1756 btrfs_mark_buffer_dirty(leaf);
1757 if (inode)
1758 btrfs_add_delayed_iput(inode);
1759 return ret;
1760}
1761
1762static noinline_for_stack
1763int memcmp_node_keys(struct extent_buffer *eb, int slot,
1764 struct btrfs_path *path, int level)
1765{
1766 struct btrfs_disk_key key1;
1767 struct btrfs_disk_key key2;
1768 btrfs_node_key(eb, &key1, slot);
1769 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1770 return memcmp(&key1, &key2, sizeof(key1));
1771}
1772
1773/*
1774 * try to replace tree blocks in fs tree with the new blocks
1775 * in reloc tree. tree blocks haven't been modified since the
1776 * reloc tree was create can be replaced.
1777 *
1778 * if a block was replaced, level of the block + 1 is returned.
1779 * if no block got replaced, 0 is returned. if there are other
1780 * errors, a negative error number is returned.
1781 */
1782static noinline_for_stack
1783int replace_path(struct btrfs_trans_handle *trans,
1784 struct btrfs_root *dest, struct btrfs_root *src,
1785 struct btrfs_path *path, struct btrfs_key *next_key,
1786 int lowest_level, int max_level)
1787{
1788 struct btrfs_fs_info *fs_info = dest->fs_info;
1789 struct extent_buffer *eb;
1790 struct extent_buffer *parent;
1791 struct btrfs_key key;
1792 u64 old_bytenr;
1793 u64 new_bytenr;
1794 u64 old_ptr_gen;
1795 u64 new_ptr_gen;
1796 u64 last_snapshot;
1797 u32 blocksize;
1798 int cow = 0;
1799 int level;
1800 int ret;
1801 int slot;
1802
1803 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1804 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1805
1806 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1807again:
1808 slot = path->slots[lowest_level];
1809 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1810
1811 eb = btrfs_lock_root_node(dest);
1812 btrfs_set_lock_blocking(eb);
1813 level = btrfs_header_level(eb);
1814
1815 if (level < lowest_level) {
1816 btrfs_tree_unlock(eb);
1817 free_extent_buffer(eb);
1818 return 0;
1819 }
1820
1821 if (cow) {
1822 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1823 BUG_ON(ret);
1824 }
1825 btrfs_set_lock_blocking(eb);
1826
1827 if (next_key) {
1828 next_key->objectid = (u64)-1;
1829 next_key->type = (u8)-1;
1830 next_key->offset = (u64)-1;
1831 }
1832
1833 parent = eb;
1834 while (1) {
1835 level = btrfs_header_level(parent);
1836 BUG_ON(level < lowest_level);
1837
1838 ret = btrfs_bin_search(parent, &key, level, &slot);
1839 if (ret && slot > 0)
1840 slot--;
1841
1842 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1843 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1844
1845 old_bytenr = btrfs_node_blockptr(parent, slot);
1846 blocksize = fs_info->nodesize;
1847 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1848
1849 if (level <= max_level) {
1850 eb = path->nodes[level];
1851 new_bytenr = btrfs_node_blockptr(eb,
1852 path->slots[level]);
1853 new_ptr_gen = btrfs_node_ptr_generation(eb,
1854 path->slots[level]);
1855 } else {
1856 new_bytenr = 0;
1857 new_ptr_gen = 0;
1858 }
1859
1860 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1861 ret = level;
1862 break;
1863 }
1864
1865 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1866 memcmp_node_keys(parent, slot, path, level)) {
1867 if (level <= lowest_level) {
1868 ret = 0;
1869 break;
1870 }
1871
1872 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen);
1873 if (IS_ERR(eb)) {
1874 ret = PTR_ERR(eb);
1875 break;
1876 } else if (!extent_buffer_uptodate(eb)) {
1877 ret = -EIO;
1878 free_extent_buffer(eb);
1879 break;
1880 }
1881 btrfs_tree_lock(eb);
1882 if (cow) {
1883 ret = btrfs_cow_block(trans, dest, eb, parent,
1884 slot, &eb);
1885 BUG_ON(ret);
1886 }
1887 btrfs_set_lock_blocking(eb);
1888
1889 btrfs_tree_unlock(parent);
1890 free_extent_buffer(parent);
1891
1892 parent = eb;
1893 continue;
1894 }
1895
1896 if (!cow) {
1897 btrfs_tree_unlock(parent);
1898 free_extent_buffer(parent);
1899 cow = 1;
1900 goto again;
1901 }
1902
1903 btrfs_node_key_to_cpu(path->nodes[level], &key,
1904 path->slots[level]);
1905 btrfs_release_path(path);
1906
1907 path->lowest_level = level;
1908 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1909 path->lowest_level = 0;
1910 BUG_ON(ret);
1911
1912 /*
1913 * Info qgroup to trace both subtrees.
1914 *
1915 * We must trace both trees.
1916 * 1) Tree reloc subtree
1917 * If not traced, we will leak data numbers
1918 * 2) Fs subtree
1919 * If not traced, we will double count old data
1920 * and tree block numbers, if current trans doesn't free
1921 * data reloc tree inode.
1922 */
1923 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1924 btrfs_header_generation(parent),
1925 btrfs_header_level(parent));
1926 if (ret < 0)
1927 break;
1928 ret = btrfs_qgroup_trace_subtree(trans, dest,
1929 path->nodes[level],
1930 btrfs_header_generation(path->nodes[level]),
1931 btrfs_header_level(path->nodes[level]));
1932 if (ret < 0)
1933 break;
1934
1935 /*
1936 * swap blocks in fs tree and reloc tree.
1937 */
1938 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1939 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1940 btrfs_mark_buffer_dirty(parent);
1941
1942 btrfs_set_node_blockptr(path->nodes[level],
1943 path->slots[level], old_bytenr);
1944 btrfs_set_node_ptr_generation(path->nodes[level],
1945 path->slots[level], old_ptr_gen);
1946 btrfs_mark_buffer_dirty(path->nodes[level]);
1947
1948 ret = btrfs_inc_extent_ref(trans, fs_info, old_bytenr,
1949 blocksize, path->nodes[level]->start,
1950 src->root_key.objectid, level - 1, 0);
1951 BUG_ON(ret);
1952 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1953 blocksize, 0, dest->root_key.objectid,
1954 level - 1, 0);
1955 BUG_ON(ret);
1956
1957 ret = btrfs_free_extent(trans, fs_info, new_bytenr, blocksize,
1958 path->nodes[level]->start,
1959 src->root_key.objectid, level - 1, 0);
1960 BUG_ON(ret);
1961
1962 ret = btrfs_free_extent(trans, fs_info, old_bytenr, blocksize,
1963 0, dest->root_key.objectid, level - 1,
1964 0);
1965 BUG_ON(ret);
1966
1967 btrfs_unlock_up_safe(path, 0);
1968
1969 ret = level;
1970 break;
1971 }
1972 btrfs_tree_unlock(parent);
1973 free_extent_buffer(parent);
1974 return ret;
1975}
1976
1977/*
1978 * helper to find next relocated block in reloc tree
1979 */
1980static noinline_for_stack
1981int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1982 int *level)
1983{
1984 struct extent_buffer *eb;
1985 int i;
1986 u64 last_snapshot;
1987 u32 nritems;
1988
1989 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1990
1991 for (i = 0; i < *level; i++) {
1992 free_extent_buffer(path->nodes[i]);
1993 path->nodes[i] = NULL;
1994 }
1995
1996 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1997 eb = path->nodes[i];
1998 nritems = btrfs_header_nritems(eb);
1999 while (path->slots[i] + 1 < nritems) {
2000 path->slots[i]++;
2001 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2002 last_snapshot)
2003 continue;
2004
2005 *level = i;
2006 return 0;
2007 }
2008 free_extent_buffer(path->nodes[i]);
2009 path->nodes[i] = NULL;
2010 }
2011 return 1;
2012}
2013
2014/*
2015 * walk down reloc tree to find relocated block of lowest level
2016 */
2017static noinline_for_stack
2018int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2019 int *level)
2020{
2021 struct btrfs_fs_info *fs_info = root->fs_info;
2022 struct extent_buffer *eb = NULL;
2023 int i;
2024 u64 bytenr;
2025 u64 ptr_gen = 0;
2026 u64 last_snapshot;
2027 u32 nritems;
2028
2029 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2030
2031 for (i = *level; i > 0; i--) {
2032 eb = path->nodes[i];
2033 nritems = btrfs_header_nritems(eb);
2034 while (path->slots[i] < nritems) {
2035 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2036 if (ptr_gen > last_snapshot)
2037 break;
2038 path->slots[i]++;
2039 }
2040 if (path->slots[i] >= nritems) {
2041 if (i == *level)
2042 break;
2043 *level = i + 1;
2044 return 0;
2045 }
2046 if (i == 1) {
2047 *level = i;
2048 return 0;
2049 }
2050
2051 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2052 eb = read_tree_block(fs_info, bytenr, ptr_gen);
2053 if (IS_ERR(eb)) {
2054 return PTR_ERR(eb);
2055 } else if (!extent_buffer_uptodate(eb)) {
2056 free_extent_buffer(eb);
2057 return -EIO;
2058 }
2059 BUG_ON(btrfs_header_level(eb) != i - 1);
2060 path->nodes[i - 1] = eb;
2061 path->slots[i - 1] = 0;
2062 }
2063 return 1;
2064}
2065
2066/*
2067 * invalidate extent cache for file extents whose key in range of
2068 * [min_key, max_key)
2069 */
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(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(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 * merge the relocated tree blocks in reloc tree with corresponding
2159 * fs tree.
2160 */
2161static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2162 struct btrfs_root *root)
2163{
2164 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2165 LIST_HEAD(inode_list);
2166 struct btrfs_key key;
2167 struct btrfs_key next_key;
2168 struct btrfs_trans_handle *trans = NULL;
2169 struct btrfs_root *reloc_root;
2170 struct btrfs_root_item *root_item;
2171 struct btrfs_path *path;
2172 struct extent_buffer *leaf;
2173 int level;
2174 int max_level;
2175 int replaced = 0;
2176 int ret;
2177 int err = 0;
2178 u32 min_reserved;
2179
2180 path = btrfs_alloc_path();
2181 if (!path)
2182 return -ENOMEM;
2183 path->reada = READA_FORWARD;
2184
2185 reloc_root = root->reloc_root;
2186 root_item = &reloc_root->root_item;
2187
2188 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2189 level = btrfs_root_level(root_item);
2190 extent_buffer_get(reloc_root->node);
2191 path->nodes[level] = reloc_root->node;
2192 path->slots[level] = 0;
2193 } else {
2194 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2195
2196 level = root_item->drop_level;
2197 BUG_ON(level == 0);
2198 path->lowest_level = level;
2199 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2200 path->lowest_level = 0;
2201 if (ret < 0) {
2202 btrfs_free_path(path);
2203 return ret;
2204 }
2205
2206 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2207 path->slots[level]);
2208 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2209
2210 btrfs_unlock_up_safe(path, 0);
2211 }
2212
2213 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2214 memset(&next_key, 0, sizeof(next_key));
2215
2216 while (1) {
2217 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2218 BTRFS_RESERVE_FLUSH_ALL);
2219 if (ret) {
2220 err = ret;
2221 goto out;
2222 }
2223 trans = btrfs_start_transaction(root, 0);
2224 if (IS_ERR(trans)) {
2225 err = PTR_ERR(trans);
2226 trans = NULL;
2227 goto out;
2228 }
2229 trans->block_rsv = rc->block_rsv;
2230
2231 replaced = 0;
2232 max_level = level;
2233
2234 ret = walk_down_reloc_tree(reloc_root, path, &level);
2235 if (ret < 0) {
2236 err = ret;
2237 goto out;
2238 }
2239 if (ret > 0)
2240 break;
2241
2242 if (!find_next_key(path, level, &key) &&
2243 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2244 ret = 0;
2245 } else {
2246 ret = replace_path(trans, root, reloc_root, path,
2247 &next_key, level, max_level);
2248 }
2249 if (ret < 0) {
2250 err = ret;
2251 goto out;
2252 }
2253
2254 if (ret > 0) {
2255 level = ret;
2256 btrfs_node_key_to_cpu(path->nodes[level], &key,
2257 path->slots[level]);
2258 replaced = 1;
2259 }
2260
2261 ret = walk_up_reloc_tree(reloc_root, path, &level);
2262 if (ret > 0)
2263 break;
2264
2265 BUG_ON(level == 0);
2266 /*
2267 * save the merging progress in the drop_progress.
2268 * this is OK since root refs == 1 in this case.
2269 */
2270 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2271 path->slots[level]);
2272 root_item->drop_level = level;
2273
2274 btrfs_end_transaction_throttle(trans);
2275 trans = NULL;
2276
2277 btrfs_btree_balance_dirty(fs_info);
2278
2279 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2280 invalidate_extent_cache(root, &key, &next_key);
2281 }
2282
2283 /*
2284 * handle the case only one block in the fs tree need to be
2285 * relocated and the block is tree root.
2286 */
2287 leaf = btrfs_lock_root_node(root);
2288 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2289 btrfs_tree_unlock(leaf);
2290 free_extent_buffer(leaf);
2291 if (ret < 0)
2292 err = ret;
2293out:
2294 btrfs_free_path(path);
2295
2296 if (err == 0) {
2297 memset(&root_item->drop_progress, 0,
2298 sizeof(root_item->drop_progress));
2299 root_item->drop_level = 0;
2300 btrfs_set_root_refs(root_item, 0);
2301 btrfs_update_reloc_root(trans, root);
2302 }
2303
2304 if (trans)
2305 btrfs_end_transaction_throttle(trans);
2306
2307 btrfs_btree_balance_dirty(fs_info);
2308
2309 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2310 invalidate_extent_cache(root, &key, &next_key);
2311
2312 return err;
2313}
2314
2315static noinline_for_stack
2316int prepare_to_merge(struct reloc_control *rc, int err)
2317{
2318 struct btrfs_root *root = rc->extent_root;
2319 struct btrfs_fs_info *fs_info = root->fs_info;
2320 struct btrfs_root *reloc_root;
2321 struct btrfs_trans_handle *trans;
2322 LIST_HEAD(reloc_roots);
2323 u64 num_bytes = 0;
2324 int ret;
2325
2326 mutex_lock(&fs_info->reloc_mutex);
2327 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2328 rc->merging_rsv_size += rc->nodes_relocated * 2;
2329 mutex_unlock(&fs_info->reloc_mutex);
2330
2331again:
2332 if (!err) {
2333 num_bytes = rc->merging_rsv_size;
2334 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2335 BTRFS_RESERVE_FLUSH_ALL);
2336 if (ret)
2337 err = ret;
2338 }
2339
2340 trans = btrfs_join_transaction(rc->extent_root);
2341 if (IS_ERR(trans)) {
2342 if (!err)
2343 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2344 num_bytes);
2345 return PTR_ERR(trans);
2346 }
2347
2348 if (!err) {
2349 if (num_bytes != rc->merging_rsv_size) {
2350 btrfs_end_transaction(trans);
2351 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2352 num_bytes);
2353 goto again;
2354 }
2355 }
2356
2357 rc->merge_reloc_tree = 1;
2358
2359 while (!list_empty(&rc->reloc_roots)) {
2360 reloc_root = list_entry(rc->reloc_roots.next,
2361 struct btrfs_root, root_list);
2362 list_del_init(&reloc_root->root_list);
2363
2364 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2365 BUG_ON(IS_ERR(root));
2366 BUG_ON(root->reloc_root != reloc_root);
2367
2368 /*
2369 * set reference count to 1, so btrfs_recover_relocation
2370 * knows it should resumes merging
2371 */
2372 if (!err)
2373 btrfs_set_root_refs(&reloc_root->root_item, 1);
2374 btrfs_update_reloc_root(trans, root);
2375
2376 list_add(&reloc_root->root_list, &reloc_roots);
2377 }
2378
2379 list_splice(&reloc_roots, &rc->reloc_roots);
2380
2381 if (!err)
2382 btrfs_commit_transaction(trans);
2383 else
2384 btrfs_end_transaction(trans);
2385 return err;
2386}
2387
2388static noinline_for_stack
2389void free_reloc_roots(struct list_head *list)
2390{
2391 struct btrfs_root *reloc_root;
2392
2393 while (!list_empty(list)) {
2394 reloc_root = list_entry(list->next, struct btrfs_root,
2395 root_list);
2396 free_extent_buffer(reloc_root->node);
2397 free_extent_buffer(reloc_root->commit_root);
2398 reloc_root->node = NULL;
2399 reloc_root->commit_root = NULL;
2400 __del_reloc_root(reloc_root);
2401 }
2402}
2403
2404static noinline_for_stack
2405void merge_reloc_roots(struct reloc_control *rc)
2406{
2407 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2408 struct btrfs_root *root;
2409 struct btrfs_root *reloc_root;
2410 LIST_HEAD(reloc_roots);
2411 int found = 0;
2412 int ret = 0;
2413again:
2414 root = rc->extent_root;
2415
2416 /*
2417 * this serializes us with btrfs_record_root_in_transaction,
2418 * we have to make sure nobody is in the middle of
2419 * adding their roots to the list while we are
2420 * doing this splice
2421 */
2422 mutex_lock(&fs_info->reloc_mutex);
2423 list_splice_init(&rc->reloc_roots, &reloc_roots);
2424 mutex_unlock(&fs_info->reloc_mutex);
2425
2426 while (!list_empty(&reloc_roots)) {
2427 found = 1;
2428 reloc_root = list_entry(reloc_roots.next,
2429 struct btrfs_root, root_list);
2430
2431 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2432 root = read_fs_root(fs_info,
2433 reloc_root->root_key.offset);
2434 BUG_ON(IS_ERR(root));
2435 BUG_ON(root->reloc_root != reloc_root);
2436
2437 ret = merge_reloc_root(rc, root);
2438 if (ret) {
2439 if (list_empty(&reloc_root->root_list))
2440 list_add_tail(&reloc_root->root_list,
2441 &reloc_roots);
2442 goto out;
2443 }
2444 } else {
2445 list_del_init(&reloc_root->root_list);
2446 }
2447
2448 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2449 if (ret < 0) {
2450 if (list_empty(&reloc_root->root_list))
2451 list_add_tail(&reloc_root->root_list,
2452 &reloc_roots);
2453 goto out;
2454 }
2455 }
2456
2457 if (found) {
2458 found = 0;
2459 goto again;
2460 }
2461out:
2462 if (ret) {
2463 btrfs_handle_fs_error(fs_info, ret, NULL);
2464 if (!list_empty(&reloc_roots))
2465 free_reloc_roots(&reloc_roots);
2466
2467 /* new reloc root may be added */
2468 mutex_lock(&fs_info->reloc_mutex);
2469 list_splice_init(&rc->reloc_roots, &reloc_roots);
2470 mutex_unlock(&fs_info->reloc_mutex);
2471 if (!list_empty(&reloc_roots))
2472 free_reloc_roots(&reloc_roots);
2473 }
2474
2475 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2476}
2477
2478static void free_block_list(struct rb_root *blocks)
2479{
2480 struct tree_block *block;
2481 struct rb_node *rb_node;
2482 while ((rb_node = rb_first(blocks))) {
2483 block = rb_entry(rb_node, struct tree_block, rb_node);
2484 rb_erase(rb_node, blocks);
2485 kfree(block);
2486 }
2487}
2488
2489static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2490 struct btrfs_root *reloc_root)
2491{
2492 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2493 struct btrfs_root *root;
2494
2495 if (reloc_root->last_trans == trans->transid)
2496 return 0;
2497
2498 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2499 BUG_ON(IS_ERR(root));
2500 BUG_ON(root->reloc_root != reloc_root);
2501
2502 return btrfs_record_root_in_trans(trans, root);
2503}
2504
2505static noinline_for_stack
2506struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2507 struct reloc_control *rc,
2508 struct backref_node *node,
2509 struct backref_edge *edges[])
2510{
2511 struct backref_node *next;
2512 struct btrfs_root *root;
2513 int index = 0;
2514
2515 next = node;
2516 while (1) {
2517 cond_resched();
2518 next = walk_up_backref(next, edges, &index);
2519 root = next->root;
2520 BUG_ON(!root);
2521 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2522
2523 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2524 record_reloc_root_in_trans(trans, root);
2525 break;
2526 }
2527
2528 btrfs_record_root_in_trans(trans, root);
2529 root = root->reloc_root;
2530
2531 if (next->new_bytenr != root->node->start) {
2532 BUG_ON(next->new_bytenr);
2533 BUG_ON(!list_empty(&next->list));
2534 next->new_bytenr = root->node->start;
2535 next->root = root;
2536 list_add_tail(&next->list,
2537 &rc->backref_cache.changed);
2538 __mark_block_processed(rc, next);
2539 break;
2540 }
2541
2542 WARN_ON(1);
2543 root = NULL;
2544 next = walk_down_backref(edges, &index);
2545 if (!next || next->level <= node->level)
2546 break;
2547 }
2548 if (!root)
2549 return NULL;
2550
2551 next = node;
2552 /* setup backref node path for btrfs_reloc_cow_block */
2553 while (1) {
2554 rc->backref_cache.path[next->level] = next;
2555 if (--index < 0)
2556 break;
2557 next = edges[index]->node[UPPER];
2558 }
2559 return root;
2560}
2561
2562/*
2563 * select a tree root for relocation. return NULL if the block
2564 * is reference counted. we should use do_relocation() in this
2565 * case. return a tree root pointer if the block isn't reference
2566 * counted. return -ENOENT if the block is root of reloc tree.
2567 */
2568static noinline_for_stack
2569struct btrfs_root *select_one_root(struct backref_node *node)
2570{
2571 struct backref_node *next;
2572 struct btrfs_root *root;
2573 struct btrfs_root *fs_root = NULL;
2574 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2575 int index = 0;
2576
2577 next = node;
2578 while (1) {
2579 cond_resched();
2580 next = walk_up_backref(next, edges, &index);
2581 root = next->root;
2582 BUG_ON(!root);
2583
2584 /* no other choice for non-references counted tree */
2585 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2586 return root;
2587
2588 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2589 fs_root = root;
2590
2591 if (next != node)
2592 return NULL;
2593
2594 next = walk_down_backref(edges, &index);
2595 if (!next || next->level <= node->level)
2596 break;
2597 }
2598
2599 if (!fs_root)
2600 return ERR_PTR(-ENOENT);
2601 return fs_root;
2602}
2603
2604static noinline_for_stack
2605u64 calcu_metadata_size(struct reloc_control *rc,
2606 struct backref_node *node, int reserve)
2607{
2608 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2609 struct backref_node *next = node;
2610 struct backref_edge *edge;
2611 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2612 u64 num_bytes = 0;
2613 int index = 0;
2614
2615 BUG_ON(reserve && node->processed);
2616
2617 while (next) {
2618 cond_resched();
2619 while (1) {
2620 if (next->processed && (reserve || next != node))
2621 break;
2622
2623 num_bytes += fs_info->nodesize;
2624
2625 if (list_empty(&next->upper))
2626 break;
2627
2628 edge = list_entry(next->upper.next,
2629 struct backref_edge, list[LOWER]);
2630 edges[index++] = edge;
2631 next = edge->node[UPPER];
2632 }
2633 next = walk_down_backref(edges, &index);
2634 }
2635 return num_bytes;
2636}
2637
2638static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2639 struct reloc_control *rc,
2640 struct backref_node *node)
2641{
2642 struct btrfs_root *root = rc->extent_root;
2643 struct btrfs_fs_info *fs_info = root->fs_info;
2644 u64 num_bytes;
2645 int ret;
2646 u64 tmp;
2647
2648 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2649
2650 trans->block_rsv = rc->block_rsv;
2651 rc->reserved_bytes += num_bytes;
2652
2653 /*
2654 * We are under a transaction here so we can only do limited flushing.
2655 * If we get an enospc just kick back -EAGAIN so we know to drop the
2656 * transaction and try to refill when we can flush all the things.
2657 */
2658 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2659 BTRFS_RESERVE_FLUSH_LIMIT);
2660 if (ret) {
2661 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2662 while (tmp <= rc->reserved_bytes)
2663 tmp <<= 1;
2664 /*
2665 * only one thread can access block_rsv at this point,
2666 * so we don't need hold lock to protect block_rsv.
2667 * we expand more reservation size here to allow enough
2668 * space for relocation and we will return eailer in
2669 * enospc case.
2670 */
2671 rc->block_rsv->size = tmp + fs_info->nodesize *
2672 RELOCATION_RESERVED_NODES;
2673 return -EAGAIN;
2674 }
2675
2676 return 0;
2677}
2678
2679/*
2680 * relocate a block tree, and then update pointers in upper level
2681 * blocks that reference the block to point to the new location.
2682 *
2683 * if called by link_to_upper, the block has already been relocated.
2684 * in that case this function just updates pointers.
2685 */
2686static int do_relocation(struct btrfs_trans_handle *trans,
2687 struct reloc_control *rc,
2688 struct backref_node *node,
2689 struct btrfs_key *key,
2690 struct btrfs_path *path, int lowest)
2691{
2692 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2693 struct backref_node *upper;
2694 struct backref_edge *edge;
2695 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2696 struct btrfs_root *root;
2697 struct extent_buffer *eb;
2698 u32 blocksize;
2699 u64 bytenr;
2700 u64 generation;
2701 int slot;
2702 int ret;
2703 int err = 0;
2704
2705 BUG_ON(lowest && node->eb);
2706
2707 path->lowest_level = node->level + 1;
2708 rc->backref_cache.path[node->level] = node;
2709 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2710 cond_resched();
2711
2712 upper = edge->node[UPPER];
2713 root = select_reloc_root(trans, rc, upper, edges);
2714 BUG_ON(!root);
2715
2716 if (upper->eb && !upper->locked) {
2717 if (!lowest) {
2718 ret = btrfs_bin_search(upper->eb, key,
2719 upper->level, &slot);
2720 BUG_ON(ret);
2721 bytenr = btrfs_node_blockptr(upper->eb, slot);
2722 if (node->eb->start == bytenr)
2723 goto next;
2724 }
2725 drop_node_buffer(upper);
2726 }
2727
2728 if (!upper->eb) {
2729 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2730 if (ret) {
2731 if (ret < 0)
2732 err = ret;
2733 else
2734 err = -ENOENT;
2735
2736 btrfs_release_path(path);
2737 break;
2738 }
2739
2740 if (!upper->eb) {
2741 upper->eb = path->nodes[upper->level];
2742 path->nodes[upper->level] = NULL;
2743 } else {
2744 BUG_ON(upper->eb != path->nodes[upper->level]);
2745 }
2746
2747 upper->locked = 1;
2748 path->locks[upper->level] = 0;
2749
2750 slot = path->slots[upper->level];
2751 btrfs_release_path(path);
2752 } else {
2753 ret = btrfs_bin_search(upper->eb, key, upper->level,
2754 &slot);
2755 BUG_ON(ret);
2756 }
2757
2758 bytenr = btrfs_node_blockptr(upper->eb, slot);
2759 if (lowest) {
2760 if (bytenr != node->bytenr) {
2761 btrfs_err(root->fs_info,
2762 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2763 bytenr, node->bytenr, slot,
2764 upper->eb->start);
2765 err = -EIO;
2766 goto next;
2767 }
2768 } else {
2769 if (node->eb->start == bytenr)
2770 goto next;
2771 }
2772
2773 blocksize = root->fs_info->nodesize;
2774 generation = btrfs_node_ptr_generation(upper->eb, slot);
2775 eb = read_tree_block(fs_info, bytenr, generation);
2776 if (IS_ERR(eb)) {
2777 err = PTR_ERR(eb);
2778 goto next;
2779 } else if (!extent_buffer_uptodate(eb)) {
2780 free_extent_buffer(eb);
2781 err = -EIO;
2782 goto next;
2783 }
2784 btrfs_tree_lock(eb);
2785 btrfs_set_lock_blocking(eb);
2786
2787 if (!node->eb) {
2788 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2789 slot, &eb);
2790 btrfs_tree_unlock(eb);
2791 free_extent_buffer(eb);
2792 if (ret < 0) {
2793 err = ret;
2794 goto next;
2795 }
2796 BUG_ON(node->eb != eb);
2797 } else {
2798 btrfs_set_node_blockptr(upper->eb, slot,
2799 node->eb->start);
2800 btrfs_set_node_ptr_generation(upper->eb, slot,
2801 trans->transid);
2802 btrfs_mark_buffer_dirty(upper->eb);
2803
2804 ret = btrfs_inc_extent_ref(trans, root->fs_info,
2805 node->eb->start, blocksize,
2806 upper->eb->start,
2807 btrfs_header_owner(upper->eb),
2808 node->level, 0);
2809 BUG_ON(ret);
2810
2811 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2812 BUG_ON(ret);
2813 }
2814next:
2815 if (!upper->pending)
2816 drop_node_buffer(upper);
2817 else
2818 unlock_node_buffer(upper);
2819 if (err)
2820 break;
2821 }
2822
2823 if (!err && node->pending) {
2824 drop_node_buffer(node);
2825 list_move_tail(&node->list, &rc->backref_cache.changed);
2826 node->pending = 0;
2827 }
2828
2829 path->lowest_level = 0;
2830 BUG_ON(err == -ENOSPC);
2831 return err;
2832}
2833
2834static int link_to_upper(struct btrfs_trans_handle *trans,
2835 struct reloc_control *rc,
2836 struct backref_node *node,
2837 struct btrfs_path *path)
2838{
2839 struct btrfs_key key;
2840
2841 btrfs_node_key_to_cpu(node->eb, &key, 0);
2842 return do_relocation(trans, rc, node, &key, path, 0);
2843}
2844
2845static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2846 struct reloc_control *rc,
2847 struct btrfs_path *path, int err)
2848{
2849 LIST_HEAD(list);
2850 struct backref_cache *cache = &rc->backref_cache;
2851 struct backref_node *node;
2852 int level;
2853 int ret;
2854
2855 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2856 while (!list_empty(&cache->pending[level])) {
2857 node = list_entry(cache->pending[level].next,
2858 struct backref_node, list);
2859 list_move_tail(&node->list, &list);
2860 BUG_ON(!node->pending);
2861
2862 if (!err) {
2863 ret = link_to_upper(trans, rc, node, path);
2864 if (ret < 0)
2865 err = ret;
2866 }
2867 }
2868 list_splice_init(&list, &cache->pending[level]);
2869 }
2870 return err;
2871}
2872
2873static void mark_block_processed(struct reloc_control *rc,
2874 u64 bytenr, u32 blocksize)
2875{
2876 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2877 EXTENT_DIRTY);
2878}
2879
2880static void __mark_block_processed(struct reloc_control *rc,
2881 struct backref_node *node)
2882{
2883 u32 blocksize;
2884 if (node->level == 0 ||
2885 in_block_group(node->bytenr, rc->block_group)) {
2886 blocksize = rc->extent_root->fs_info->nodesize;
2887 mark_block_processed(rc, node->bytenr, blocksize);
2888 }
2889 node->processed = 1;
2890}
2891
2892/*
2893 * mark a block and all blocks directly/indirectly reference the block
2894 * as processed.
2895 */
2896static void update_processed_blocks(struct reloc_control *rc,
2897 struct backref_node *node)
2898{
2899 struct backref_node *next = node;
2900 struct backref_edge *edge;
2901 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2902 int index = 0;
2903
2904 while (next) {
2905 cond_resched();
2906 while (1) {
2907 if (next->processed)
2908 break;
2909
2910 __mark_block_processed(rc, next);
2911
2912 if (list_empty(&next->upper))
2913 break;
2914
2915 edge = list_entry(next->upper.next,
2916 struct backref_edge, list[LOWER]);
2917 edges[index++] = edge;
2918 next = edge->node[UPPER];
2919 }
2920 next = walk_down_backref(edges, &index);
2921 }
2922}
2923
2924static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2925{
2926 u32 blocksize = rc->extent_root->fs_info->nodesize;
2927
2928 if (test_range_bit(&rc->processed_blocks, bytenr,
2929 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2930 return 1;
2931 return 0;
2932}
2933
2934static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2935 struct tree_block *block)
2936{
2937 struct extent_buffer *eb;
2938
2939 BUG_ON(block->key_ready);
2940 eb = read_tree_block(fs_info, block->bytenr, block->key.offset);
2941 if (IS_ERR(eb)) {
2942 return PTR_ERR(eb);
2943 } else if (!extent_buffer_uptodate(eb)) {
2944 free_extent_buffer(eb);
2945 return -EIO;
2946 }
2947 WARN_ON(btrfs_header_level(eb) != block->level);
2948 if (block->level == 0)
2949 btrfs_item_key_to_cpu(eb, &block->key, 0);
2950 else
2951 btrfs_node_key_to_cpu(eb, &block->key, 0);
2952 free_extent_buffer(eb);
2953 block->key_ready = 1;
2954 return 0;
2955}
2956
2957/*
2958 * helper function to relocate a tree block
2959 */
2960static int relocate_tree_block(struct btrfs_trans_handle *trans,
2961 struct reloc_control *rc,
2962 struct backref_node *node,
2963 struct btrfs_key *key,
2964 struct btrfs_path *path)
2965{
2966 struct btrfs_root *root;
2967 int ret = 0;
2968
2969 if (!node)
2970 return 0;
2971
2972 BUG_ON(node->processed);
2973 root = select_one_root(node);
2974 if (root == ERR_PTR(-ENOENT)) {
2975 update_processed_blocks(rc, node);
2976 goto out;
2977 }
2978
2979 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2980 ret = reserve_metadata_space(trans, rc, node);
2981 if (ret)
2982 goto out;
2983 }
2984
2985 if (root) {
2986 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
2987 BUG_ON(node->new_bytenr);
2988 BUG_ON(!list_empty(&node->list));
2989 btrfs_record_root_in_trans(trans, root);
2990 root = root->reloc_root;
2991 node->new_bytenr = root->node->start;
2992 node->root = root;
2993 list_add_tail(&node->list, &rc->backref_cache.changed);
2994 } else {
2995 path->lowest_level = node->level;
2996 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2997 btrfs_release_path(path);
2998 if (ret > 0)
2999 ret = 0;
3000 }
3001 if (!ret)
3002 update_processed_blocks(rc, node);
3003 } else {
3004 ret = do_relocation(trans, rc, node, key, path, 1);
3005 }
3006out:
3007 if (ret || node->level == 0 || node->cowonly)
3008 remove_backref_node(&rc->backref_cache, node);
3009 return ret;
3010}
3011
3012/*
3013 * relocate a list of blocks
3014 */
3015static noinline_for_stack
3016int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3017 struct reloc_control *rc, struct rb_root *blocks)
3018{
3019 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3020 struct backref_node *node;
3021 struct btrfs_path *path;
3022 struct tree_block *block;
3023 struct rb_node *rb_node;
3024 int ret;
3025 int err = 0;
3026
3027 path = btrfs_alloc_path();
3028 if (!path) {
3029 err = -ENOMEM;
3030 goto out_free_blocks;
3031 }
3032
3033 rb_node = rb_first(blocks);
3034 while (rb_node) {
3035 block = rb_entry(rb_node, struct tree_block, rb_node);
3036 if (!block->key_ready)
3037 readahead_tree_block(fs_info, block->bytenr);
3038 rb_node = rb_next(rb_node);
3039 }
3040
3041 rb_node = rb_first(blocks);
3042 while (rb_node) {
3043 block = rb_entry(rb_node, struct tree_block, rb_node);
3044 if (!block->key_ready) {
3045 err = get_tree_block_key(fs_info, block);
3046 if (err)
3047 goto out_free_path;
3048 }
3049 rb_node = rb_next(rb_node);
3050 }
3051
3052 rb_node = rb_first(blocks);
3053 while (rb_node) {
3054 block = rb_entry(rb_node, struct tree_block, rb_node);
3055
3056 node = build_backref_tree(rc, &block->key,
3057 block->level, block->bytenr);
3058 if (IS_ERR(node)) {
3059 err = PTR_ERR(node);
3060 goto out;
3061 }
3062
3063 ret = relocate_tree_block(trans, rc, node, &block->key,
3064 path);
3065 if (ret < 0) {
3066 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3067 err = ret;
3068 goto out;
3069 }
3070 rb_node = rb_next(rb_node);
3071 }
3072out:
3073 err = finish_pending_nodes(trans, rc, path, err);
3074
3075out_free_path:
3076 btrfs_free_path(path);
3077out_free_blocks:
3078 free_block_list(blocks);
3079 return err;
3080}
3081
3082static noinline_for_stack
3083int prealloc_file_extent_cluster(struct inode *inode,
3084 struct file_extent_cluster *cluster)
3085{
3086 u64 alloc_hint = 0;
3087 u64 start;
3088 u64 end;
3089 u64 offset = BTRFS_I(inode)->index_cnt;
3090 u64 num_bytes;
3091 int nr = 0;
3092 int ret = 0;
3093 u64 prealloc_start = cluster->start - offset;
3094 u64 prealloc_end = cluster->end - offset;
3095 u64 cur_offset;
3096
3097 BUG_ON(cluster->start != cluster->boundary[0]);
3098 inode_lock(inode);
3099
3100 ret = btrfs_check_data_free_space(inode, prealloc_start,
3101 prealloc_end + 1 - prealloc_start);
3102 if (ret)
3103 goto out;
3104
3105 cur_offset = prealloc_start;
3106 while (nr < cluster->nr) {
3107 start = cluster->boundary[nr] - offset;
3108 if (nr + 1 < cluster->nr)
3109 end = cluster->boundary[nr + 1] - 1 - offset;
3110 else
3111 end = cluster->end - offset;
3112
3113 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3114 num_bytes = end + 1 - start;
3115 if (cur_offset < start)
3116 btrfs_free_reserved_data_space(inode, cur_offset,
3117 start - cur_offset);
3118 ret = btrfs_prealloc_file_range(inode, 0, start,
3119 num_bytes, num_bytes,
3120 end + 1, &alloc_hint);
3121 cur_offset = end + 1;
3122 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3123 if (ret)
3124 break;
3125 nr++;
3126 }
3127 if (cur_offset < prealloc_end)
3128 btrfs_free_reserved_data_space(inode, cur_offset,
3129 prealloc_end + 1 - cur_offset);
3130out:
3131 inode_unlock(inode);
3132 return ret;
3133}
3134
3135static noinline_for_stack
3136int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3137 u64 block_start)
3138{
3139 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3140 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3141 struct extent_map *em;
3142 int ret = 0;
3143
3144 em = alloc_extent_map();
3145 if (!em)
3146 return -ENOMEM;
3147
3148 em->start = start;
3149 em->len = end + 1 - start;
3150 em->block_len = em->len;
3151 em->block_start = block_start;
3152 em->bdev = fs_info->fs_devices->latest_bdev;
3153 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3154
3155 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3156 while (1) {
3157 write_lock(&em_tree->lock);
3158 ret = add_extent_mapping(em_tree, em, 0);
3159 write_unlock(&em_tree->lock);
3160 if (ret != -EEXIST) {
3161 free_extent_map(em);
3162 break;
3163 }
3164 btrfs_drop_extent_cache(inode, start, end, 0);
3165 }
3166 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3167 return ret;
3168}
3169
3170static int relocate_file_extent_cluster(struct inode *inode,
3171 struct file_extent_cluster *cluster)
3172{
3173 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3174 u64 page_start;
3175 u64 page_end;
3176 u64 offset = BTRFS_I(inode)->index_cnt;
3177 unsigned long index;
3178 unsigned long last_index;
3179 struct page *page;
3180 struct file_ra_state *ra;
3181 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3182 int nr = 0;
3183 int ret = 0;
3184
3185 if (!cluster->nr)
3186 return 0;
3187
3188 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3189 if (!ra)
3190 return -ENOMEM;
3191
3192 ret = prealloc_file_extent_cluster(inode, cluster);
3193 if (ret)
3194 goto out;
3195
3196 file_ra_state_init(ra, inode->i_mapping);
3197
3198 ret = setup_extent_mapping(inode, cluster->start - offset,
3199 cluster->end - offset, cluster->start);
3200 if (ret)
3201 goto out;
3202
3203 index = (cluster->start - offset) >> PAGE_SHIFT;
3204 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3205 while (index <= last_index) {
3206 ret = btrfs_delalloc_reserve_metadata(inode, PAGE_SIZE);
3207 if (ret)
3208 goto out;
3209
3210 page = find_lock_page(inode->i_mapping, index);
3211 if (!page) {
3212 page_cache_sync_readahead(inode->i_mapping,
3213 ra, NULL, index,
3214 last_index + 1 - index);
3215 page = find_or_create_page(inode->i_mapping, index,
3216 mask);
3217 if (!page) {
3218 btrfs_delalloc_release_metadata(inode,
3219 PAGE_SIZE);
3220 ret = -ENOMEM;
3221 goto out;
3222 }
3223 }
3224
3225 if (PageReadahead(page)) {
3226 page_cache_async_readahead(inode->i_mapping,
3227 ra, NULL, page, index,
3228 last_index + 1 - index);
3229 }
3230
3231 if (!PageUptodate(page)) {
3232 btrfs_readpage(NULL, page);
3233 lock_page(page);
3234 if (!PageUptodate(page)) {
3235 unlock_page(page);
3236 put_page(page);
3237 btrfs_delalloc_release_metadata(inode,
3238 PAGE_SIZE);
3239 ret = -EIO;
3240 goto out;
3241 }
3242 }
3243
3244 page_start = page_offset(page);
3245 page_end = page_start + PAGE_SIZE - 1;
3246
3247 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3248
3249 set_page_extent_mapped(page);
3250
3251 if (nr < cluster->nr &&
3252 page_start + offset == cluster->boundary[nr]) {
3253 set_extent_bits(&BTRFS_I(inode)->io_tree,
3254 page_start, page_end,
3255 EXTENT_BOUNDARY);
3256 nr++;
3257 }
3258
3259 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL, 0);
3260 set_page_dirty(page);
3261
3262 unlock_extent(&BTRFS_I(inode)->io_tree,
3263 page_start, page_end);
3264 unlock_page(page);
3265 put_page(page);
3266
3267 index++;
3268 balance_dirty_pages_ratelimited(inode->i_mapping);
3269 btrfs_throttle(fs_info);
3270 }
3271 WARN_ON(nr != cluster->nr);
3272out:
3273 kfree(ra);
3274 return ret;
3275}
3276
3277static noinline_for_stack
3278int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3279 struct file_extent_cluster *cluster)
3280{
3281 int ret;
3282
3283 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3284 ret = relocate_file_extent_cluster(inode, cluster);
3285 if (ret)
3286 return ret;
3287 cluster->nr = 0;
3288 }
3289
3290 if (!cluster->nr)
3291 cluster->start = extent_key->objectid;
3292 else
3293 BUG_ON(cluster->nr >= MAX_EXTENTS);
3294 cluster->end = extent_key->objectid + extent_key->offset - 1;
3295 cluster->boundary[cluster->nr] = extent_key->objectid;
3296 cluster->nr++;
3297
3298 if (cluster->nr >= MAX_EXTENTS) {
3299 ret = relocate_file_extent_cluster(inode, cluster);
3300 if (ret)
3301 return ret;
3302 cluster->nr = 0;
3303 }
3304 return 0;
3305}
3306
3307#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3308static int get_ref_objectid_v0(struct reloc_control *rc,
3309 struct btrfs_path *path,
3310 struct btrfs_key *extent_key,
3311 u64 *ref_objectid, int *path_change)
3312{
3313 struct btrfs_key key;
3314 struct extent_buffer *leaf;
3315 struct btrfs_extent_ref_v0 *ref0;
3316 int ret;
3317 int slot;
3318
3319 leaf = path->nodes[0];
3320 slot = path->slots[0];
3321 while (1) {
3322 if (slot >= btrfs_header_nritems(leaf)) {
3323 ret = btrfs_next_leaf(rc->extent_root, path);
3324 if (ret < 0)
3325 return ret;
3326 BUG_ON(ret > 0);
3327 leaf = path->nodes[0];
3328 slot = path->slots[0];
3329 if (path_change)
3330 *path_change = 1;
3331 }
3332 btrfs_item_key_to_cpu(leaf, &key, slot);
3333 if (key.objectid != extent_key->objectid)
3334 return -ENOENT;
3335
3336 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3337 slot++;
3338 continue;
3339 }
3340 ref0 = btrfs_item_ptr(leaf, slot,
3341 struct btrfs_extent_ref_v0);
3342 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3343 break;
3344 }
3345 return 0;
3346}
3347#endif
3348
3349/*
3350 * helper to add a tree block to the list.
3351 * the major work is getting the generation and level of the block
3352 */
3353static int add_tree_block(struct reloc_control *rc,
3354 struct btrfs_key *extent_key,
3355 struct btrfs_path *path,
3356 struct rb_root *blocks)
3357{
3358 struct extent_buffer *eb;
3359 struct btrfs_extent_item *ei;
3360 struct btrfs_tree_block_info *bi;
3361 struct tree_block *block;
3362 struct rb_node *rb_node;
3363 u32 item_size;
3364 int level = -1;
3365 u64 generation;
3366
3367 eb = path->nodes[0];
3368 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3369
3370 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3371 item_size >= sizeof(*ei) + sizeof(*bi)) {
3372 ei = btrfs_item_ptr(eb, path->slots[0],
3373 struct btrfs_extent_item);
3374 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3375 bi = (struct btrfs_tree_block_info *)(ei + 1);
3376 level = btrfs_tree_block_level(eb, bi);
3377 } else {
3378 level = (int)extent_key->offset;
3379 }
3380 generation = btrfs_extent_generation(eb, ei);
3381 } else {
3382#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3383 u64 ref_owner;
3384 int ret;
3385
3386 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3387 ret = get_ref_objectid_v0(rc, path, extent_key,
3388 &ref_owner, NULL);
3389 if (ret < 0)
3390 return ret;
3391 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3392 level = (int)ref_owner;
3393 /* FIXME: get real generation */
3394 generation = 0;
3395#else
3396 BUG();
3397#endif
3398 }
3399
3400 btrfs_release_path(path);
3401
3402 BUG_ON(level == -1);
3403
3404 block = kmalloc(sizeof(*block), GFP_NOFS);
3405 if (!block)
3406 return -ENOMEM;
3407
3408 block->bytenr = extent_key->objectid;
3409 block->key.objectid = rc->extent_root->fs_info->nodesize;
3410 block->key.offset = generation;
3411 block->level = level;
3412 block->key_ready = 0;
3413
3414 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3415 if (rb_node)
3416 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3417
3418 return 0;
3419}
3420
3421/*
3422 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3423 */
3424static int __add_tree_block(struct reloc_control *rc,
3425 u64 bytenr, u32 blocksize,
3426 struct rb_root *blocks)
3427{
3428 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3429 struct btrfs_path *path;
3430 struct btrfs_key key;
3431 int ret;
3432 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3433
3434 if (tree_block_processed(bytenr, rc))
3435 return 0;
3436
3437 if (tree_search(blocks, bytenr))
3438 return 0;
3439
3440 path = btrfs_alloc_path();
3441 if (!path)
3442 return -ENOMEM;
3443again:
3444 key.objectid = bytenr;
3445 if (skinny) {
3446 key.type = BTRFS_METADATA_ITEM_KEY;
3447 key.offset = (u64)-1;
3448 } else {
3449 key.type = BTRFS_EXTENT_ITEM_KEY;
3450 key.offset = blocksize;
3451 }
3452
3453 path->search_commit_root = 1;
3454 path->skip_locking = 1;
3455 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3456 if (ret < 0)
3457 goto out;
3458
3459 if (ret > 0 && skinny) {
3460 if (path->slots[0]) {
3461 path->slots[0]--;
3462 btrfs_item_key_to_cpu(path->nodes[0], &key,
3463 path->slots[0]);
3464 if (key.objectid == bytenr &&
3465 (key.type == BTRFS_METADATA_ITEM_KEY ||
3466 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3467 key.offset == blocksize)))
3468 ret = 0;
3469 }
3470
3471 if (ret) {
3472 skinny = false;
3473 btrfs_release_path(path);
3474 goto again;
3475 }
3476 }
3477 BUG_ON(ret);
3478
3479 ret = add_tree_block(rc, &key, path, blocks);
3480out:
3481 btrfs_free_path(path);
3482 return ret;
3483}
3484
3485/*
3486 * helper to check if the block use full backrefs for pointers in it
3487 */
3488static int block_use_full_backref(struct reloc_control *rc,
3489 struct extent_buffer *eb)
3490{
3491 u64 flags;
3492 int ret;
3493
3494 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3495 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3496 return 1;
3497
3498 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3499 eb->start, btrfs_header_level(eb), 1,
3500 NULL, &flags);
3501 BUG_ON(ret);
3502
3503 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3504 ret = 1;
3505 else
3506 ret = 0;
3507 return ret;
3508}
3509
3510static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3511 struct btrfs_block_group_cache *block_group,
3512 struct inode *inode,
3513 u64 ino)
3514{
3515 struct btrfs_key key;
3516 struct btrfs_root *root = fs_info->tree_root;
3517 struct btrfs_trans_handle *trans;
3518 int ret = 0;
3519
3520 if (inode)
3521 goto truncate;
3522
3523 key.objectid = ino;
3524 key.type = BTRFS_INODE_ITEM_KEY;
3525 key.offset = 0;
3526
3527 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3528 if (IS_ERR(inode) || is_bad_inode(inode)) {
3529 if (!IS_ERR(inode))
3530 iput(inode);
3531 return -ENOENT;
3532 }
3533
3534truncate:
3535 ret = btrfs_check_trunc_cache_free_space(fs_info,
3536 &fs_info->global_block_rsv);
3537 if (ret)
3538 goto out;
3539
3540 trans = btrfs_join_transaction(root);
3541 if (IS_ERR(trans)) {
3542 ret = PTR_ERR(trans);
3543 goto out;
3544 }
3545
3546 ret = btrfs_truncate_free_space_cache(root, trans, block_group, inode);
3547
3548 btrfs_end_transaction(trans);
3549 btrfs_btree_balance_dirty(fs_info);
3550out:
3551 iput(inode);
3552 return ret;
3553}
3554
3555/*
3556 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3557 * this function scans fs tree to find blocks reference the data extent
3558 */
3559static int find_data_references(struct reloc_control *rc,
3560 struct btrfs_key *extent_key,
3561 struct extent_buffer *leaf,
3562 struct btrfs_extent_data_ref *ref,
3563 struct rb_root *blocks)
3564{
3565 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3566 struct btrfs_path *path;
3567 struct tree_block *block;
3568 struct btrfs_root *root;
3569 struct btrfs_file_extent_item *fi;
3570 struct rb_node *rb_node;
3571 struct btrfs_key key;
3572 u64 ref_root;
3573 u64 ref_objectid;
3574 u64 ref_offset;
3575 u32 ref_count;
3576 u32 nritems;
3577 int err = 0;
3578 int added = 0;
3579 int counted;
3580 int ret;
3581
3582 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3583 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3584 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3585 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3586
3587 /*
3588 * This is an extent belonging to the free space cache, lets just delete
3589 * it and redo the search.
3590 */
3591 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3592 ret = delete_block_group_cache(fs_info, rc->block_group,
3593 NULL, ref_objectid);
3594 if (ret != -ENOENT)
3595 return ret;
3596 ret = 0;
3597 }
3598
3599 path = btrfs_alloc_path();
3600 if (!path)
3601 return -ENOMEM;
3602 path->reada = READA_FORWARD;
3603
3604 root = read_fs_root(fs_info, ref_root);
3605 if (IS_ERR(root)) {
3606 err = PTR_ERR(root);
3607 goto out;
3608 }
3609
3610 key.objectid = ref_objectid;
3611 key.type = BTRFS_EXTENT_DATA_KEY;
3612 if (ref_offset > ((u64)-1 << 32))
3613 key.offset = 0;
3614 else
3615 key.offset = ref_offset;
3616
3617 path->search_commit_root = 1;
3618 path->skip_locking = 1;
3619 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3620 if (ret < 0) {
3621 err = ret;
3622 goto out;
3623 }
3624
3625 leaf = path->nodes[0];
3626 nritems = btrfs_header_nritems(leaf);
3627 /*
3628 * the references in tree blocks that use full backrefs
3629 * are not counted in
3630 */
3631 if (block_use_full_backref(rc, leaf))
3632 counted = 0;
3633 else
3634 counted = 1;
3635 rb_node = tree_search(blocks, leaf->start);
3636 if (rb_node) {
3637 if (counted)
3638 added = 1;
3639 else
3640 path->slots[0] = nritems;
3641 }
3642
3643 while (ref_count > 0) {
3644 while (path->slots[0] >= nritems) {
3645 ret = btrfs_next_leaf(root, path);
3646 if (ret < 0) {
3647 err = ret;
3648 goto out;
3649 }
3650 if (WARN_ON(ret > 0))
3651 goto out;
3652
3653 leaf = path->nodes[0];
3654 nritems = btrfs_header_nritems(leaf);
3655 added = 0;
3656
3657 if (block_use_full_backref(rc, leaf))
3658 counted = 0;
3659 else
3660 counted = 1;
3661 rb_node = tree_search(blocks, leaf->start);
3662 if (rb_node) {
3663 if (counted)
3664 added = 1;
3665 else
3666 path->slots[0] = nritems;
3667 }
3668 }
3669
3670 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3671 if (WARN_ON(key.objectid != ref_objectid ||
3672 key.type != BTRFS_EXTENT_DATA_KEY))
3673 break;
3674
3675 fi = btrfs_item_ptr(leaf, path->slots[0],
3676 struct btrfs_file_extent_item);
3677
3678 if (btrfs_file_extent_type(leaf, fi) ==
3679 BTRFS_FILE_EXTENT_INLINE)
3680 goto next;
3681
3682 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3683 extent_key->objectid)
3684 goto next;
3685
3686 key.offset -= btrfs_file_extent_offset(leaf, fi);
3687 if (key.offset != ref_offset)
3688 goto next;
3689
3690 if (counted)
3691 ref_count--;
3692 if (added)
3693 goto next;
3694
3695 if (!tree_block_processed(leaf->start, rc)) {
3696 block = kmalloc(sizeof(*block), GFP_NOFS);
3697 if (!block) {
3698 err = -ENOMEM;
3699 break;
3700 }
3701 block->bytenr = leaf->start;
3702 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3703 block->level = 0;
3704 block->key_ready = 1;
3705 rb_node = tree_insert(blocks, block->bytenr,
3706 &block->rb_node);
3707 if (rb_node)
3708 backref_tree_panic(rb_node, -EEXIST,
3709 block->bytenr);
3710 }
3711 if (counted)
3712 added = 1;
3713 else
3714 path->slots[0] = nritems;
3715next:
3716 path->slots[0]++;
3717
3718 }
3719out:
3720 btrfs_free_path(path);
3721 return err;
3722}
3723
3724/*
3725 * helper to find all tree blocks that reference a given data extent
3726 */
3727static noinline_for_stack
3728int add_data_references(struct reloc_control *rc,
3729 struct btrfs_key *extent_key,
3730 struct btrfs_path *path,
3731 struct rb_root *blocks)
3732{
3733 struct btrfs_key key;
3734 struct extent_buffer *eb;
3735 struct btrfs_extent_data_ref *dref;
3736 struct btrfs_extent_inline_ref *iref;
3737 unsigned long ptr;
3738 unsigned long end;
3739 u32 blocksize = rc->extent_root->fs_info->nodesize;
3740 int ret = 0;
3741 int err = 0;
3742
3743 eb = path->nodes[0];
3744 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3745 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3746#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3747 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3748 ptr = end;
3749 else
3750#endif
3751 ptr += sizeof(struct btrfs_extent_item);
3752
3753 while (ptr < end) {
3754 iref = (struct btrfs_extent_inline_ref *)ptr;
3755 key.type = btrfs_extent_inline_ref_type(eb, iref);
3756 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3757 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3758 ret = __add_tree_block(rc, key.offset, blocksize,
3759 blocks);
3760 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3761 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3762 ret = find_data_references(rc, extent_key,
3763 eb, dref, blocks);
3764 } else {
3765 BUG();
3766 }
3767 if (ret) {
3768 err = ret;
3769 goto out;
3770 }
3771 ptr += btrfs_extent_inline_ref_size(key.type);
3772 }
3773 WARN_ON(ptr > end);
3774
3775 while (1) {
3776 cond_resched();
3777 eb = path->nodes[0];
3778 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3779 ret = btrfs_next_leaf(rc->extent_root, path);
3780 if (ret < 0) {
3781 err = ret;
3782 break;
3783 }
3784 if (ret > 0)
3785 break;
3786 eb = path->nodes[0];
3787 }
3788
3789 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3790 if (key.objectid != extent_key->objectid)
3791 break;
3792
3793#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3794 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3795 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3796#else
3797 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3798 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3799#endif
3800 ret = __add_tree_block(rc, key.offset, blocksize,
3801 blocks);
3802 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3803 dref = btrfs_item_ptr(eb, path->slots[0],
3804 struct btrfs_extent_data_ref);
3805 ret = find_data_references(rc, extent_key,
3806 eb, dref, blocks);
3807 } else {
3808 ret = 0;
3809 }
3810 if (ret) {
3811 err = ret;
3812 break;
3813 }
3814 path->slots[0]++;
3815 }
3816out:
3817 btrfs_release_path(path);
3818 if (err)
3819 free_block_list(blocks);
3820 return err;
3821}
3822
3823/*
3824 * helper to find next unprocessed extent
3825 */
3826static noinline_for_stack
3827int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3828 struct btrfs_key *extent_key)
3829{
3830 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3831 struct btrfs_key key;
3832 struct extent_buffer *leaf;
3833 u64 start, end, last;
3834 int ret;
3835
3836 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3837 while (1) {
3838 cond_resched();
3839 if (rc->search_start >= last) {
3840 ret = 1;
3841 break;
3842 }
3843
3844 key.objectid = rc->search_start;
3845 key.type = BTRFS_EXTENT_ITEM_KEY;
3846 key.offset = 0;
3847
3848 path->search_commit_root = 1;
3849 path->skip_locking = 1;
3850 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3851 0, 0);
3852 if (ret < 0)
3853 break;
3854next:
3855 leaf = path->nodes[0];
3856 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3857 ret = btrfs_next_leaf(rc->extent_root, path);
3858 if (ret != 0)
3859 break;
3860 leaf = path->nodes[0];
3861 }
3862
3863 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3864 if (key.objectid >= last) {
3865 ret = 1;
3866 break;
3867 }
3868
3869 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3870 key.type != BTRFS_METADATA_ITEM_KEY) {
3871 path->slots[0]++;
3872 goto next;
3873 }
3874
3875 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3876 key.objectid + key.offset <= rc->search_start) {
3877 path->slots[0]++;
3878 goto next;
3879 }
3880
3881 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3882 key.objectid + fs_info->nodesize <=
3883 rc->search_start) {
3884 path->slots[0]++;
3885 goto next;
3886 }
3887
3888 ret = find_first_extent_bit(&rc->processed_blocks,
3889 key.objectid, &start, &end,
3890 EXTENT_DIRTY, NULL);
3891
3892 if (ret == 0 && start <= key.objectid) {
3893 btrfs_release_path(path);
3894 rc->search_start = end + 1;
3895 } else {
3896 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3897 rc->search_start = key.objectid + key.offset;
3898 else
3899 rc->search_start = key.objectid +
3900 fs_info->nodesize;
3901 memcpy(extent_key, &key, sizeof(key));
3902 return 0;
3903 }
3904 }
3905 btrfs_release_path(path);
3906 return ret;
3907}
3908
3909static void set_reloc_control(struct reloc_control *rc)
3910{
3911 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3912
3913 mutex_lock(&fs_info->reloc_mutex);
3914 fs_info->reloc_ctl = rc;
3915 mutex_unlock(&fs_info->reloc_mutex);
3916}
3917
3918static void unset_reloc_control(struct reloc_control *rc)
3919{
3920 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3921
3922 mutex_lock(&fs_info->reloc_mutex);
3923 fs_info->reloc_ctl = NULL;
3924 mutex_unlock(&fs_info->reloc_mutex);
3925}
3926
3927static int check_extent_flags(u64 flags)
3928{
3929 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3930 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3931 return 1;
3932 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3933 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3934 return 1;
3935 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3936 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3937 return 1;
3938 return 0;
3939}
3940
3941static noinline_for_stack
3942int prepare_to_relocate(struct reloc_control *rc)
3943{
3944 struct btrfs_trans_handle *trans;
3945 int ret;
3946
3947 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3948 BTRFS_BLOCK_RSV_TEMP);
3949 if (!rc->block_rsv)
3950 return -ENOMEM;
3951
3952 memset(&rc->cluster, 0, sizeof(rc->cluster));
3953 rc->search_start = rc->block_group->key.objectid;
3954 rc->extents_found = 0;
3955 rc->nodes_relocated = 0;
3956 rc->merging_rsv_size = 0;
3957 rc->reserved_bytes = 0;
3958 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3959 RELOCATION_RESERVED_NODES;
3960 ret = btrfs_block_rsv_refill(rc->extent_root,
3961 rc->block_rsv, rc->block_rsv->size,
3962 BTRFS_RESERVE_FLUSH_ALL);
3963 if (ret)
3964 return ret;
3965
3966 rc->create_reloc_tree = 1;
3967 set_reloc_control(rc);
3968
3969 trans = btrfs_join_transaction(rc->extent_root);
3970 if (IS_ERR(trans)) {
3971 unset_reloc_control(rc);
3972 /*
3973 * extent tree is not a ref_cow tree and has no reloc_root to
3974 * cleanup. And callers are responsible to free the above
3975 * block rsv.
3976 */
3977 return PTR_ERR(trans);
3978 }
3979 btrfs_commit_transaction(trans);
3980 return 0;
3981}
3982
3983static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3984{
3985 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3986 struct rb_root blocks = RB_ROOT;
3987 struct btrfs_key key;
3988 struct btrfs_trans_handle *trans = NULL;
3989 struct btrfs_path *path;
3990 struct btrfs_extent_item *ei;
3991 u64 flags;
3992 u32 item_size;
3993 int ret;
3994 int err = 0;
3995 int progress = 0;
3996
3997 path = btrfs_alloc_path();
3998 if (!path)
3999 return -ENOMEM;
4000 path->reada = READA_FORWARD;
4001
4002 ret = prepare_to_relocate(rc);
4003 if (ret) {
4004 err = ret;
4005 goto out_free;
4006 }
4007
4008 while (1) {
4009 rc->reserved_bytes = 0;
4010 ret = btrfs_block_rsv_refill(rc->extent_root,
4011 rc->block_rsv, rc->block_rsv->size,
4012 BTRFS_RESERVE_FLUSH_ALL);
4013 if (ret) {
4014 err = ret;
4015 break;
4016 }
4017 progress++;
4018 trans = btrfs_start_transaction(rc->extent_root, 0);
4019 if (IS_ERR(trans)) {
4020 err = PTR_ERR(trans);
4021 trans = NULL;
4022 break;
4023 }
4024restart:
4025 if (update_backref_cache(trans, &rc->backref_cache)) {
4026 btrfs_end_transaction(trans);
4027 continue;
4028 }
4029
4030 ret = find_next_extent(rc, path, &key);
4031 if (ret < 0)
4032 err = ret;
4033 if (ret != 0)
4034 break;
4035
4036 rc->extents_found++;
4037
4038 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4039 struct btrfs_extent_item);
4040 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4041 if (item_size >= sizeof(*ei)) {
4042 flags = btrfs_extent_flags(path->nodes[0], ei);
4043 ret = check_extent_flags(flags);
4044 BUG_ON(ret);
4045
4046 } else {
4047#ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4048 u64 ref_owner;
4049 int path_change = 0;
4050
4051 BUG_ON(item_size !=
4052 sizeof(struct btrfs_extent_item_v0));
4053 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4054 &path_change);
4055 if (ret < 0) {
4056 err = ret;
4057 break;
4058 }
4059 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4060 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4061 else
4062 flags = BTRFS_EXTENT_FLAG_DATA;
4063
4064 if (path_change) {
4065 btrfs_release_path(path);
4066
4067 path->search_commit_root = 1;
4068 path->skip_locking = 1;
4069 ret = btrfs_search_slot(NULL, rc->extent_root,
4070 &key, path, 0, 0);
4071 if (ret < 0) {
4072 err = ret;
4073 break;
4074 }
4075 BUG_ON(ret > 0);
4076 }
4077#else
4078 BUG();
4079#endif
4080 }
4081
4082 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4083 ret = add_tree_block(rc, &key, path, &blocks);
4084 } else if (rc->stage == UPDATE_DATA_PTRS &&
4085 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4086 ret = add_data_references(rc, &key, path, &blocks);
4087 } else {
4088 btrfs_release_path(path);
4089 ret = 0;
4090 }
4091 if (ret < 0) {
4092 err = ret;
4093 break;
4094 }
4095
4096 if (!RB_EMPTY_ROOT(&blocks)) {
4097 ret = relocate_tree_blocks(trans, rc, &blocks);
4098 if (ret < 0) {
4099 /*
4100 * if we fail to relocate tree blocks, force to update
4101 * backref cache when committing transaction.
4102 */
4103 rc->backref_cache.last_trans = trans->transid - 1;
4104
4105 if (ret != -EAGAIN) {
4106 err = ret;
4107 break;
4108 }
4109 rc->extents_found--;
4110 rc->search_start = key.objectid;
4111 }
4112 }
4113
4114 btrfs_end_transaction_throttle(trans);
4115 btrfs_btree_balance_dirty(fs_info);
4116 trans = NULL;
4117
4118 if (rc->stage == MOVE_DATA_EXTENTS &&
4119 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4120 rc->found_file_extent = 1;
4121 ret = relocate_data_extent(rc->data_inode,
4122 &key, &rc->cluster);
4123 if (ret < 0) {
4124 err = ret;
4125 break;
4126 }
4127 }
4128 }
4129 if (trans && progress && err == -ENOSPC) {
4130 ret = btrfs_force_chunk_alloc(trans, fs_info,
4131 rc->block_group->flags);
4132 if (ret == 1) {
4133 err = 0;
4134 progress = 0;
4135 goto restart;
4136 }
4137 }
4138
4139 btrfs_release_path(path);
4140 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4141
4142 if (trans) {
4143 btrfs_end_transaction_throttle(trans);
4144 btrfs_btree_balance_dirty(fs_info);
4145 }
4146
4147 if (!err) {
4148 ret = relocate_file_extent_cluster(rc->data_inode,
4149 &rc->cluster);
4150 if (ret < 0)
4151 err = ret;
4152 }
4153
4154 rc->create_reloc_tree = 0;
4155 set_reloc_control(rc);
4156
4157 backref_cache_cleanup(&rc->backref_cache);
4158 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4159
4160 err = prepare_to_merge(rc, err);
4161
4162 merge_reloc_roots(rc);
4163
4164 rc->merge_reloc_tree = 0;
4165 unset_reloc_control(rc);
4166 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4167
4168 /* get rid of pinned extents */
4169 trans = btrfs_join_transaction(rc->extent_root);
4170 if (IS_ERR(trans)) {
4171 err = PTR_ERR(trans);
4172 goto out_free;
4173 }
4174 btrfs_commit_transaction(trans);
4175out_free:
4176 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4177 btrfs_free_path(path);
4178 return err;
4179}
4180
4181static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4182 struct btrfs_root *root, u64 objectid)
4183{
4184 struct btrfs_path *path;
4185 struct btrfs_inode_item *item;
4186 struct extent_buffer *leaf;
4187 int ret;
4188
4189 path = btrfs_alloc_path();
4190 if (!path)
4191 return -ENOMEM;
4192
4193 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4194 if (ret)
4195 goto out;
4196
4197 leaf = path->nodes[0];
4198 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4199 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4200 btrfs_set_inode_generation(leaf, item, 1);
4201 btrfs_set_inode_size(leaf, item, 0);
4202 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4203 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4204 BTRFS_INODE_PREALLOC);
4205 btrfs_mark_buffer_dirty(leaf);
4206out:
4207 btrfs_free_path(path);
4208 return ret;
4209}
4210
4211/*
4212 * helper to create inode for data relocation.
4213 * the inode is in data relocation tree and its link count is 0
4214 */
4215static noinline_for_stack
4216struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4217 struct btrfs_block_group_cache *group)
4218{
4219 struct inode *inode = NULL;
4220 struct btrfs_trans_handle *trans;
4221 struct btrfs_root *root;
4222 struct btrfs_key key;
4223 u64 objectid;
4224 int err = 0;
4225
4226 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4227 if (IS_ERR(root))
4228 return ERR_CAST(root);
4229
4230 trans = btrfs_start_transaction(root, 6);
4231 if (IS_ERR(trans))
4232 return ERR_CAST(trans);
4233
4234 err = btrfs_find_free_objectid(root, &objectid);
4235 if (err)
4236 goto out;
4237
4238 err = __insert_orphan_inode(trans, root, objectid);
4239 BUG_ON(err);
4240
4241 key.objectid = objectid;
4242 key.type = BTRFS_INODE_ITEM_KEY;
4243 key.offset = 0;
4244 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4245 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4246 BTRFS_I(inode)->index_cnt = group->key.objectid;
4247
4248 err = btrfs_orphan_add(trans, inode);
4249out:
4250 btrfs_end_transaction(trans);
4251 btrfs_btree_balance_dirty(fs_info);
4252 if (err) {
4253 if (inode)
4254 iput(inode);
4255 inode = ERR_PTR(err);
4256 }
4257 return inode;
4258}
4259
4260static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4261{
4262 struct reloc_control *rc;
4263
4264 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4265 if (!rc)
4266 return NULL;
4267
4268 INIT_LIST_HEAD(&rc->reloc_roots);
4269 backref_cache_init(&rc->backref_cache);
4270 mapping_tree_init(&rc->reloc_root_tree);
4271 extent_io_tree_init(&rc->processed_blocks,
4272 fs_info->btree_inode->i_mapping);
4273 return rc;
4274}
4275
4276/*
4277 * Print the block group being relocated
4278 */
4279static void describe_relocation(struct btrfs_fs_info *fs_info,
4280 struct btrfs_block_group_cache *block_group)
4281{
4282 char buf[128]; /* prefixed by a '|' that'll be dropped */
4283 u64 flags = block_group->flags;
4284
4285 /* Shouldn't happen */
4286 if (!flags) {
4287 strcpy(buf, "|NONE");
4288 } else {
4289 char *bp = buf;
4290
4291#define DESCRIBE_FLAG(f, d) \
4292 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4293 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4294 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4295 }
4296 DESCRIBE_FLAG(DATA, "data");
4297 DESCRIBE_FLAG(SYSTEM, "system");
4298 DESCRIBE_FLAG(METADATA, "metadata");
4299 DESCRIBE_FLAG(RAID0, "raid0");
4300 DESCRIBE_FLAG(RAID1, "raid1");
4301 DESCRIBE_FLAG(DUP, "dup");
4302 DESCRIBE_FLAG(RAID10, "raid10");
4303 DESCRIBE_FLAG(RAID5, "raid5");
4304 DESCRIBE_FLAG(RAID6, "raid6");
4305 if (flags)
4306 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4307#undef DESCRIBE_FLAG
4308 }
4309
4310 btrfs_info(fs_info,
4311 "relocating block group %llu flags %s",
4312 block_group->key.objectid, buf + 1);
4313}
4314
4315/*
4316 * function to relocate all extents in a block group.
4317 */
4318int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4319{
4320 struct btrfs_root *extent_root = fs_info->extent_root;
4321 struct reloc_control *rc;
4322 struct inode *inode;
4323 struct btrfs_path *path;
4324 int ret;
4325 int rw = 0;
4326 int err = 0;
4327
4328 rc = alloc_reloc_control(fs_info);
4329 if (!rc)
4330 return -ENOMEM;
4331
4332 rc->extent_root = extent_root;
4333
4334 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4335 BUG_ON(!rc->block_group);
4336
4337 ret = btrfs_inc_block_group_ro(extent_root, rc->block_group);
4338 if (ret) {
4339 err = ret;
4340 goto out;
4341 }
4342 rw = 1;
4343
4344 path = btrfs_alloc_path();
4345 if (!path) {
4346 err = -ENOMEM;
4347 goto out;
4348 }
4349
4350 inode = lookup_free_space_inode(fs_info->tree_root, rc->block_group,
4351 path);
4352 btrfs_free_path(path);
4353
4354 if (!IS_ERR(inode))
4355 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4356 else
4357 ret = PTR_ERR(inode);
4358
4359 if (ret && ret != -ENOENT) {
4360 err = ret;
4361 goto out;
4362 }
4363
4364 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4365 if (IS_ERR(rc->data_inode)) {
4366 err = PTR_ERR(rc->data_inode);
4367 rc->data_inode = NULL;
4368 goto out;
4369 }
4370
4371 describe_relocation(fs_info, rc->block_group);
4372
4373 btrfs_wait_block_group_reservations(rc->block_group);
4374 btrfs_wait_nocow_writers(rc->block_group);
4375 btrfs_wait_ordered_roots(fs_info, -1,
4376 rc->block_group->key.objectid,
4377 rc->block_group->key.offset);
4378
4379 while (1) {
4380 mutex_lock(&fs_info->cleaner_mutex);
4381 ret = relocate_block_group(rc);
4382 mutex_unlock(&fs_info->cleaner_mutex);
4383 if (ret < 0) {
4384 err = ret;
4385 goto out;
4386 }
4387
4388 if (rc->extents_found == 0)
4389 break;
4390
4391 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4392
4393 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4394 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4395 (u64)-1);
4396 if (ret) {
4397 err = ret;
4398 goto out;
4399 }
4400 invalidate_mapping_pages(rc->data_inode->i_mapping,
4401 0, -1);
4402 rc->stage = UPDATE_DATA_PTRS;
4403 }
4404 }
4405
4406 WARN_ON(rc->block_group->pinned > 0);
4407 WARN_ON(rc->block_group->reserved > 0);
4408 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
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);
4580out_free:
4581 kfree(rc);
4582out:
4583 if (!list_empty(&reloc_roots))
4584 free_reloc_roots(&reloc_roots);
4585
4586 btrfs_free_path(path);
4587
4588 if (err == 0) {
4589 /* cleanup orphan inode in data relocation tree */
4590 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4591 if (IS_ERR(fs_root))
4592 err = PTR_ERR(fs_root);
4593 else
4594 err = btrfs_orphan_cleanup(fs_root);
4595 }
4596 return err;
4597}
4598
4599/*
4600 * helper to add ordered checksum for data relocation.
4601 *
4602 * cloning checksum properly handles the nodatasum extents.
4603 * it also saves CPU time to re-calculate the checksum.
4604 */
4605int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4606{
4607 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4608 struct btrfs_ordered_sum *sums;
4609 struct btrfs_ordered_extent *ordered;
4610 int ret;
4611 u64 disk_bytenr;
4612 u64 new_bytenr;
4613 LIST_HEAD(list);
4614
4615 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4616 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4617
4618 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4619 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4620 disk_bytenr + len - 1, &list, 0);
4621 if (ret)
4622 goto out;
4623
4624 while (!list_empty(&list)) {
4625 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4626 list_del_init(&sums->list);
4627
4628 /*
4629 * We need to offset the new_bytenr based on where the csum is.
4630 * We need to do this because we will read in entire prealloc
4631 * extents but we may have written to say the middle of the
4632 * prealloc extent, so we need to make sure the csum goes with
4633 * the right disk offset.
4634 *
4635 * We can do this because the data reloc inode refers strictly
4636 * to the on disk bytes, so we don't have to worry about
4637 * disk_len vs real len like with real inodes since it's all
4638 * disk length.
4639 */
4640 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4641 sums->bytenr = new_bytenr;
4642
4643 btrfs_add_ordered_sum(inode, ordered, sums);
4644 }
4645out:
4646 btrfs_put_ordered_extent(ordered);
4647 return ret;
4648}
4649
4650int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4651 struct btrfs_root *root, struct extent_buffer *buf,
4652 struct extent_buffer *cow)
4653{
4654 struct btrfs_fs_info *fs_info = root->fs_info;
4655 struct reloc_control *rc;
4656 struct backref_node *node;
4657 int first_cow = 0;
4658 int level;
4659 int ret = 0;
4660
4661 rc = fs_info->reloc_ctl;
4662 if (!rc)
4663 return 0;
4664
4665 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4666 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4667
4668 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4669 if (buf == root->node)
4670 __update_reloc_root(root, cow->start);
4671 }
4672
4673 level = btrfs_header_level(buf);
4674 if (btrfs_header_generation(buf) <=
4675 btrfs_root_last_snapshot(&root->root_item))
4676 first_cow = 1;
4677
4678 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4679 rc->create_reloc_tree) {
4680 WARN_ON(!first_cow && level == 0);
4681
4682 node = rc->backref_cache.path[level];
4683 BUG_ON(node->bytenr != buf->start &&
4684 node->new_bytenr != buf->start);
4685
4686 drop_node_buffer(node);
4687 extent_buffer_get(cow);
4688 node->eb = cow;
4689 node->new_bytenr = cow->start;
4690
4691 if (!node->pending) {
4692 list_move_tail(&node->list,
4693 &rc->backref_cache.pending[level]);
4694 node->pending = 1;
4695 }
4696
4697 if (first_cow)
4698 __mark_block_processed(rc, node);
4699
4700 if (first_cow && level > 0)
4701 rc->nodes_relocated += buf->len;
4702 }
4703
4704 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4705 ret = replace_file_extents(trans, rc, root, cow);
4706 return ret;
4707}
4708
4709/*
4710 * called before creating snapshot. it calculates metadata reservation
4711 * required for relocating tree blocks in the snapshot
4712 */
4713void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4714 u64 *bytes_to_reserve)
4715{
4716 struct btrfs_root *root;
4717 struct reloc_control *rc;
4718
4719 root = pending->root;
4720 if (!root->reloc_root)
4721 return;
4722
4723 rc = root->fs_info->reloc_ctl;
4724 if (!rc->merge_reloc_tree)
4725 return;
4726
4727 root = root->reloc_root;
4728 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4729 /*
4730 * relocation is in the stage of merging trees. the space
4731 * used by merging a reloc tree is twice the size of
4732 * relocated tree nodes in the worst case. half for cowing
4733 * the reloc tree, half for cowing the fs tree. the space
4734 * used by cowing the reloc tree will be freed after the
4735 * tree is dropped. if we create snapshot, cowing the fs
4736 * tree may use more space than it frees. so we need
4737 * reserve extra space.
4738 */
4739 *bytes_to_reserve += rc->nodes_relocated;
4740}
4741
4742/*
4743 * called after snapshot is created. migrate block reservation
4744 * and create reloc root for the newly created snapshot
4745 */
4746int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4747 struct btrfs_pending_snapshot *pending)
4748{
4749 struct btrfs_root *root = pending->root;
4750 struct btrfs_root *reloc_root;
4751 struct btrfs_root *new_root;
4752 struct reloc_control *rc;
4753 int ret;
4754
4755 if (!root->reloc_root)
4756 return 0;
4757
4758 rc = root->fs_info->reloc_ctl;
4759 rc->merging_rsv_size += rc->nodes_relocated;
4760
4761 if (rc->merge_reloc_tree) {
4762 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4763 rc->block_rsv,
4764 rc->nodes_relocated, 1);
4765 if (ret)
4766 return ret;
4767 }
4768
4769 new_root = pending->snap;
4770 reloc_root = create_reloc_root(trans, root->reloc_root,
4771 new_root->root_key.objectid);
4772 if (IS_ERR(reloc_root))
4773 return PTR_ERR(reloc_root);
4774
4775 ret = __add_reloc_root(reloc_root);
4776 BUG_ON(ret < 0);
4777 new_root->reloc_root = reloc_root;
4778
4779 if (rc->create_reloc_tree)
4780 ret = clone_backref_node(trans, rc, root, reloc_root);
4781 return ret;
4782}
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#include "raid-stripe-tree.h"
40
41/*
42 * Relocation overview
43 *
44 * [What does relocation do]
45 *
46 * The objective of relocation is to relocate all extents of the target block
47 * group to other block groups.
48 * This is utilized by resize (shrink only), profile converting, compacting
49 * space, or balance routine to spread chunks over devices.
50 *
51 * Before | After
52 * ------------------------------------------------------------------
53 * BG A: 10 data extents | BG A: deleted
54 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
55 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
56 *
57 * [How does relocation work]
58 *
59 * 1. Mark the target block group read-only
60 * New extents won't be allocated from the target block group.
61 *
62 * 2.1 Record each extent in the target block group
63 * To build a proper map of extents to be relocated.
64 *
65 * 2.2 Build data reloc tree and reloc trees
66 * Data reloc tree will contain an inode, recording all newly relocated
67 * data extents.
68 * There will be only one data reloc tree for one data block group.
69 *
70 * Reloc tree will be a special snapshot of its source tree, containing
71 * relocated tree blocks.
72 * Each tree referring to a tree block in target block group will get its
73 * reloc tree built.
74 *
75 * 2.3 Swap source tree with its corresponding reloc tree
76 * Each involved tree only refers to new extents after swap.
77 *
78 * 3. Cleanup reloc trees and data reloc tree.
79 * As old extents in the target block group are still referenced by reloc
80 * trees, we need to clean them up before really freeing the target block
81 * group.
82 *
83 * The main complexity is in steps 2.2 and 2.3.
84 *
85 * The entry point of relocation is relocate_block_group() function.
86 */
87
88#define RELOCATION_RESERVED_NODES 256
89/*
90 * map address of tree root to tree
91 */
92struct mapping_node {
93 struct {
94 struct rb_node rb_node;
95 u64 bytenr;
96 }; /* Use rb_simle_node for search/insert */
97 void *data;
98};
99
100struct mapping_tree {
101 struct rb_root rb_root;
102 spinlock_t lock;
103};
104
105/*
106 * present a tree block to process
107 */
108struct tree_block {
109 struct {
110 struct rb_node rb_node;
111 u64 bytenr;
112 }; /* Use rb_simple_node for search/insert */
113 u64 owner;
114 struct btrfs_key key;
115 u8 level;
116 bool key_ready;
117};
118
119#define MAX_EXTENTS 128
120
121struct file_extent_cluster {
122 u64 start;
123 u64 end;
124 u64 boundary[MAX_EXTENTS];
125 unsigned int nr;
126 u64 owning_root;
127};
128
129/* Stages of data relocation. */
130enum reloc_stage {
131 MOVE_DATA_EXTENTS,
132 UPDATE_DATA_PTRS
133};
134
135struct reloc_control {
136 /* block group to relocate */
137 struct btrfs_block_group *block_group;
138 /* extent tree */
139 struct btrfs_root *extent_root;
140 /* inode for moving data */
141 struct inode *data_inode;
142
143 struct btrfs_block_rsv *block_rsv;
144
145 struct btrfs_backref_cache backref_cache;
146
147 struct file_extent_cluster cluster;
148 /* tree blocks have been processed */
149 struct extent_io_tree processed_blocks;
150 /* map start of tree root to corresponding reloc tree */
151 struct mapping_tree reloc_root_tree;
152 /* list of reloc trees */
153 struct list_head reloc_roots;
154 /* list of subvolume trees that get relocated */
155 struct list_head dirty_subvol_roots;
156 /* size of metadata reservation for merging reloc trees */
157 u64 merging_rsv_size;
158 /* size of relocated tree nodes */
159 u64 nodes_relocated;
160 /* reserved size for block group relocation*/
161 u64 reserved_bytes;
162
163 u64 search_start;
164 u64 extents_found;
165
166 enum reloc_stage stage;
167 bool create_reloc_tree;
168 bool merge_reloc_tree;
169 bool found_file_extent;
170};
171
172static void mark_block_processed(struct reloc_control *rc,
173 struct btrfs_backref_node *node)
174{
175 u32 blocksize;
176
177 if (node->level == 0 ||
178 in_range(node->bytenr, rc->block_group->start,
179 rc->block_group->length)) {
180 blocksize = rc->extent_root->fs_info->nodesize;
181 set_extent_bit(&rc->processed_blocks, node->bytenr,
182 node->bytenr + blocksize - 1, EXTENT_DIRTY, NULL);
183 }
184 node->processed = 1;
185}
186
187/*
188 * walk up backref nodes until reach node presents tree root
189 */
190static struct btrfs_backref_node *walk_up_backref(
191 struct btrfs_backref_node *node,
192 struct btrfs_backref_edge *edges[], int *index)
193{
194 struct btrfs_backref_edge *edge;
195 int idx = *index;
196
197 while (!list_empty(&node->upper)) {
198 edge = list_entry(node->upper.next,
199 struct btrfs_backref_edge, list[LOWER]);
200 edges[idx++] = edge;
201 node = edge->node[UPPER];
202 }
203 BUG_ON(node->detached);
204 *index = idx;
205 return node;
206}
207
208/*
209 * walk down backref nodes to find start of next reference path
210 */
211static struct btrfs_backref_node *walk_down_backref(
212 struct btrfs_backref_edge *edges[], int *index)
213{
214 struct btrfs_backref_edge *edge;
215 struct btrfs_backref_node *lower;
216 int idx = *index;
217
218 while (idx > 0) {
219 edge = edges[idx - 1];
220 lower = edge->node[LOWER];
221 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
222 idx--;
223 continue;
224 }
225 edge = list_entry(edge->list[LOWER].next,
226 struct btrfs_backref_edge, list[LOWER]);
227 edges[idx - 1] = edge;
228 *index = idx;
229 return edge->node[UPPER];
230 }
231 *index = 0;
232 return NULL;
233}
234
235static bool reloc_root_is_dead(const struct btrfs_root *root)
236{
237 /*
238 * Pair with set_bit/clear_bit in clean_dirty_subvols and
239 * btrfs_update_reloc_root. We need to see the updated bit before
240 * trying to access reloc_root
241 */
242 smp_rmb();
243 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
244 return true;
245 return false;
246}
247
248/*
249 * Check if this subvolume tree has valid reloc tree.
250 *
251 * Reloc tree after swap is considered dead, thus not considered as valid.
252 * This is enough for most callers, as they don't distinguish dead reloc root
253 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
254 * special case.
255 */
256static bool have_reloc_root(const struct btrfs_root *root)
257{
258 if (reloc_root_is_dead(root))
259 return false;
260 if (!root->reloc_root)
261 return false;
262 return true;
263}
264
265bool btrfs_should_ignore_reloc_root(const struct btrfs_root *root)
266{
267 struct btrfs_root *reloc_root;
268
269 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
270 return false;
271
272 /* This root has been merged with its reloc tree, we can ignore it */
273 if (reloc_root_is_dead(root))
274 return true;
275
276 reloc_root = root->reloc_root;
277 if (!reloc_root)
278 return false;
279
280 if (btrfs_header_generation(reloc_root->commit_root) ==
281 root->fs_info->running_transaction->transid)
282 return false;
283 /*
284 * If there is reloc tree and it was created in previous transaction
285 * backref lookup can find the reloc tree, so backref node for the fs
286 * tree root is useless for relocation.
287 */
288 return true;
289}
290
291/*
292 * find reloc tree by address of tree root
293 */
294struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
295{
296 struct reloc_control *rc = fs_info->reloc_ctl;
297 struct rb_node *rb_node;
298 struct mapping_node *node;
299 struct btrfs_root *root = NULL;
300
301 ASSERT(rc);
302 spin_lock(&rc->reloc_root_tree.lock);
303 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
304 if (rb_node) {
305 node = rb_entry(rb_node, struct mapping_node, rb_node);
306 root = node->data;
307 }
308 spin_unlock(&rc->reloc_root_tree.lock);
309 return btrfs_grab_root(root);
310}
311
312/*
313 * For useless nodes, do two major clean ups:
314 *
315 * - Cleanup the children edges and nodes
316 * If child node is also orphan (no parent) during cleanup, then the child
317 * node will also be cleaned up.
318 *
319 * - Freeing up leaves (level 0), keeps nodes detached
320 * For nodes, the node is still cached as "detached"
321 *
322 * Return false if @node is not in the @useless_nodes list.
323 * Return true if @node is in the @useless_nodes list.
324 */
325static bool handle_useless_nodes(struct reloc_control *rc,
326 struct btrfs_backref_node *node)
327{
328 struct btrfs_backref_cache *cache = &rc->backref_cache;
329 struct list_head *useless_node = &cache->useless_node;
330 bool ret = false;
331
332 while (!list_empty(useless_node)) {
333 struct btrfs_backref_node *cur;
334
335 cur = list_first_entry(useless_node, struct btrfs_backref_node,
336 list);
337 list_del_init(&cur->list);
338
339 /* Only tree root nodes can be added to @useless_nodes */
340 ASSERT(list_empty(&cur->upper));
341
342 if (cur == node)
343 ret = true;
344
345 /* The node is the lowest node */
346 if (cur->lowest) {
347 list_del_init(&cur->lower);
348 cur->lowest = 0;
349 }
350
351 /* Cleanup the lower edges */
352 while (!list_empty(&cur->lower)) {
353 struct btrfs_backref_edge *edge;
354 struct btrfs_backref_node *lower;
355
356 edge = list_entry(cur->lower.next,
357 struct btrfs_backref_edge, list[UPPER]);
358 list_del(&edge->list[UPPER]);
359 list_del(&edge->list[LOWER]);
360 lower = edge->node[LOWER];
361 btrfs_backref_free_edge(cache, edge);
362
363 /* Child node is also orphan, queue for cleanup */
364 if (list_empty(&lower->upper))
365 list_add(&lower->list, useless_node);
366 }
367 /* Mark this block processed for relocation */
368 mark_block_processed(rc, cur);
369
370 /*
371 * Backref nodes for tree leaves are deleted from the cache.
372 * Backref nodes for upper level tree blocks are left in the
373 * cache to avoid unnecessary backref lookup.
374 */
375 if (cur->level > 0) {
376 list_add(&cur->list, &cache->detached);
377 cur->detached = 1;
378 } else {
379 rb_erase(&cur->rb_node, &cache->rb_root);
380 btrfs_backref_free_node(cache, cur);
381 }
382 }
383 return ret;
384}
385
386/*
387 * Build backref tree for a given tree block. Root of the backref tree
388 * corresponds the tree block, leaves of the backref tree correspond roots of
389 * b-trees that reference the tree block.
390 *
391 * The basic idea of this function is check backrefs of a given block to find
392 * upper level blocks that reference the block, and then check backrefs of
393 * these upper level blocks recursively. The recursion stops when tree root is
394 * reached or backrefs for the block is cached.
395 *
396 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
397 * all upper level blocks that directly/indirectly reference the block are also
398 * cached.
399 */
400static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
401 struct btrfs_trans_handle *trans,
402 struct reloc_control *rc, struct btrfs_key *node_key,
403 int level, u64 bytenr)
404{
405 struct btrfs_backref_iter *iter;
406 struct btrfs_backref_cache *cache = &rc->backref_cache;
407 /* For searching parent of TREE_BLOCK_REF */
408 struct btrfs_path *path;
409 struct btrfs_backref_node *cur;
410 struct btrfs_backref_node *node = NULL;
411 struct btrfs_backref_edge *edge;
412 int ret;
413
414 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info);
415 if (!iter)
416 return ERR_PTR(-ENOMEM);
417 path = btrfs_alloc_path();
418 if (!path) {
419 ret = -ENOMEM;
420 goto out;
421 }
422
423 node = btrfs_backref_alloc_node(cache, bytenr, level);
424 if (!node) {
425 ret = -ENOMEM;
426 goto out;
427 }
428
429 node->lowest = 1;
430 cur = node;
431
432 /* Breadth-first search to build backref cache */
433 do {
434 ret = btrfs_backref_add_tree_node(trans, cache, path, iter,
435 node_key, cur);
436 if (ret < 0)
437 goto out;
438
439 edge = list_first_entry_or_null(&cache->pending_edge,
440 struct btrfs_backref_edge, list[UPPER]);
441 /*
442 * The pending list isn't empty, take the first block to
443 * process
444 */
445 if (edge) {
446 list_del_init(&edge->list[UPPER]);
447 cur = edge->node[UPPER];
448 }
449 } while (edge);
450
451 /* Finish the upper linkage of newly added edges/nodes */
452 ret = btrfs_backref_finish_upper_links(cache, node);
453 if (ret < 0)
454 goto out;
455
456 if (handle_useless_nodes(rc, node))
457 node = NULL;
458out:
459 btrfs_free_path(iter->path);
460 kfree(iter);
461 btrfs_free_path(path);
462 if (ret) {
463 btrfs_backref_error_cleanup(cache, node);
464 return ERR_PTR(ret);
465 }
466 ASSERT(!node || !node->detached);
467 ASSERT(list_empty(&cache->useless_node) &&
468 list_empty(&cache->pending_edge));
469 return node;
470}
471
472/*
473 * helper to add backref node for the newly created snapshot.
474 * the backref node is created by cloning backref node that
475 * corresponds to root of source tree
476 */
477static int clone_backref_node(struct btrfs_trans_handle *trans,
478 struct reloc_control *rc,
479 const struct btrfs_root *src,
480 struct btrfs_root *dest)
481{
482 struct btrfs_root *reloc_root = src->reloc_root;
483 struct btrfs_backref_cache *cache = &rc->backref_cache;
484 struct btrfs_backref_node *node = NULL;
485 struct btrfs_backref_node *new_node;
486 struct btrfs_backref_edge *edge;
487 struct btrfs_backref_edge *new_edge;
488 struct rb_node *rb_node;
489
490 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
491 if (rb_node) {
492 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
493 if (node->detached)
494 node = NULL;
495 else
496 BUG_ON(node->new_bytenr != reloc_root->node->start);
497 }
498
499 if (!node) {
500 rb_node = rb_simple_search(&cache->rb_root,
501 reloc_root->commit_root->start);
502 if (rb_node) {
503 node = rb_entry(rb_node, struct btrfs_backref_node,
504 rb_node);
505 BUG_ON(node->detached);
506 }
507 }
508
509 if (!node)
510 return 0;
511
512 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
513 node->level);
514 if (!new_node)
515 return -ENOMEM;
516
517 new_node->lowest = node->lowest;
518 new_node->checked = 1;
519 new_node->root = btrfs_grab_root(dest);
520 ASSERT(new_node->root);
521
522 if (!node->lowest) {
523 list_for_each_entry(edge, &node->lower, list[UPPER]) {
524 new_edge = btrfs_backref_alloc_edge(cache);
525 if (!new_edge)
526 goto fail;
527
528 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
529 new_node, LINK_UPPER);
530 }
531 } else {
532 list_add_tail(&new_node->lower, &cache->leaves);
533 }
534
535 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
536 &new_node->rb_node);
537 if (rb_node)
538 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
539
540 if (!new_node->lowest) {
541 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
542 list_add_tail(&new_edge->list[LOWER],
543 &new_edge->node[LOWER]->upper);
544 }
545 }
546 return 0;
547fail:
548 while (!list_empty(&new_node->lower)) {
549 new_edge = list_entry(new_node->lower.next,
550 struct btrfs_backref_edge, list[UPPER]);
551 list_del(&new_edge->list[UPPER]);
552 btrfs_backref_free_edge(cache, new_edge);
553 }
554 btrfs_backref_free_node(cache, new_node);
555 return -ENOMEM;
556}
557
558/*
559 * helper to add 'address of tree root -> reloc tree' mapping
560 */
561static int __add_reloc_root(struct btrfs_root *root)
562{
563 struct btrfs_fs_info *fs_info = root->fs_info;
564 struct rb_node *rb_node;
565 struct mapping_node *node;
566 struct reloc_control *rc = fs_info->reloc_ctl;
567
568 node = kmalloc(sizeof(*node), GFP_NOFS);
569 if (!node)
570 return -ENOMEM;
571
572 node->bytenr = root->commit_root->start;
573 node->data = root;
574
575 spin_lock(&rc->reloc_root_tree.lock);
576 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
577 node->bytenr, &node->rb_node);
578 spin_unlock(&rc->reloc_root_tree.lock);
579 if (rb_node) {
580 btrfs_err(fs_info,
581 "Duplicate root found for start=%llu while inserting into relocation tree",
582 node->bytenr);
583 return -EEXIST;
584 }
585
586 list_add_tail(&root->root_list, &rc->reloc_roots);
587 return 0;
588}
589
590/*
591 * helper to delete the 'address of tree root -> reloc tree'
592 * mapping
593 */
594static void __del_reloc_root(struct btrfs_root *root)
595{
596 struct btrfs_fs_info *fs_info = root->fs_info;
597 struct rb_node *rb_node;
598 struct mapping_node *node = NULL;
599 struct reloc_control *rc = fs_info->reloc_ctl;
600 bool put_ref = false;
601
602 if (rc && root->node) {
603 spin_lock(&rc->reloc_root_tree.lock);
604 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
605 root->commit_root->start);
606 if (rb_node) {
607 node = rb_entry(rb_node, struct mapping_node, rb_node);
608 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
609 RB_CLEAR_NODE(&node->rb_node);
610 }
611 spin_unlock(&rc->reloc_root_tree.lock);
612 ASSERT(!node || (struct btrfs_root *)node->data == root);
613 }
614
615 /*
616 * We only put the reloc root here if it's on the list. There's a lot
617 * of places where the pattern is to splice the rc->reloc_roots, process
618 * the reloc roots, and then add the reloc root back onto
619 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
620 * list we don't want the reference being dropped, because the guy
621 * messing with the list is in charge of the reference.
622 */
623 spin_lock(&fs_info->trans_lock);
624 if (!list_empty(&root->root_list)) {
625 put_ref = true;
626 list_del_init(&root->root_list);
627 }
628 spin_unlock(&fs_info->trans_lock);
629 if (put_ref)
630 btrfs_put_root(root);
631 kfree(node);
632}
633
634/*
635 * helper to update the 'address of tree root -> reloc tree'
636 * mapping
637 */
638static int __update_reloc_root(struct btrfs_root *root)
639{
640 struct btrfs_fs_info *fs_info = root->fs_info;
641 struct rb_node *rb_node;
642 struct mapping_node *node = NULL;
643 struct reloc_control *rc = fs_info->reloc_ctl;
644
645 spin_lock(&rc->reloc_root_tree.lock);
646 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
647 root->commit_root->start);
648 if (rb_node) {
649 node = rb_entry(rb_node, struct mapping_node, rb_node);
650 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
651 }
652 spin_unlock(&rc->reloc_root_tree.lock);
653
654 if (!node)
655 return 0;
656 BUG_ON((struct btrfs_root *)node->data != root);
657
658 spin_lock(&rc->reloc_root_tree.lock);
659 node->bytenr = root->node->start;
660 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
661 node->bytenr, &node->rb_node);
662 spin_unlock(&rc->reloc_root_tree.lock);
663 if (rb_node)
664 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
665 return 0;
666}
667
668static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
669 struct btrfs_root *root, u64 objectid)
670{
671 struct btrfs_fs_info *fs_info = root->fs_info;
672 struct btrfs_root *reloc_root;
673 struct extent_buffer *eb;
674 struct btrfs_root_item *root_item;
675 struct btrfs_key root_key;
676 int ret = 0;
677 bool must_abort = false;
678
679 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
680 if (!root_item)
681 return ERR_PTR(-ENOMEM);
682
683 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
684 root_key.type = BTRFS_ROOT_ITEM_KEY;
685 root_key.offset = objectid;
686
687 if (btrfs_root_id(root) == objectid) {
688 u64 commit_root_gen;
689
690 /* called by btrfs_init_reloc_root */
691 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
692 BTRFS_TREE_RELOC_OBJECTID);
693 if (ret)
694 goto fail;
695
696 /*
697 * Set the last_snapshot field to the generation of the commit
698 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
699 * correctly (returns true) when the relocation root is created
700 * either inside the critical section of a transaction commit
701 * (through transaction.c:qgroup_account_snapshot()) and when
702 * it's created before the transaction commit is started.
703 */
704 commit_root_gen = btrfs_header_generation(root->commit_root);
705 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
706 } else {
707 /*
708 * called by btrfs_reloc_post_snapshot_hook.
709 * the source tree is a reloc tree, all tree blocks
710 * modified after it was created have RELOC flag
711 * set in their headers. so it's OK to not update
712 * the 'last_snapshot'.
713 */
714 ret = btrfs_copy_root(trans, root, root->node, &eb,
715 BTRFS_TREE_RELOC_OBJECTID);
716 if (ret)
717 goto fail;
718 }
719
720 /*
721 * We have changed references at this point, we must abort the
722 * transaction if anything fails.
723 */
724 must_abort = true;
725
726 memcpy(root_item, &root->root_item, sizeof(*root_item));
727 btrfs_set_root_bytenr(root_item, eb->start);
728 btrfs_set_root_level(root_item, btrfs_header_level(eb));
729 btrfs_set_root_generation(root_item, trans->transid);
730
731 if (btrfs_root_id(root) == objectid) {
732 btrfs_set_root_refs(root_item, 0);
733 memset(&root_item->drop_progress, 0,
734 sizeof(struct btrfs_disk_key));
735 btrfs_set_root_drop_level(root_item, 0);
736 }
737
738 btrfs_tree_unlock(eb);
739 free_extent_buffer(eb);
740
741 ret = btrfs_insert_root(trans, fs_info->tree_root,
742 &root_key, root_item);
743 if (ret)
744 goto fail;
745
746 kfree(root_item);
747
748 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
749 if (IS_ERR(reloc_root)) {
750 ret = PTR_ERR(reloc_root);
751 goto abort;
752 }
753 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
754 btrfs_set_root_last_trans(reloc_root, trans->transid);
755 return reloc_root;
756fail:
757 kfree(root_item);
758abort:
759 if (must_abort)
760 btrfs_abort_transaction(trans, ret);
761 return ERR_PTR(ret);
762}
763
764/*
765 * create reloc tree for a given fs tree. reloc tree is just a
766 * snapshot of the fs tree with special root objectid.
767 *
768 * The reloc_root comes out of here with two references, one for
769 * root->reloc_root, and another for being on the rc->reloc_roots list.
770 */
771int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
772 struct btrfs_root *root)
773{
774 struct btrfs_fs_info *fs_info = root->fs_info;
775 struct btrfs_root *reloc_root;
776 struct reloc_control *rc = fs_info->reloc_ctl;
777 struct btrfs_block_rsv *rsv;
778 int clear_rsv = 0;
779 int ret;
780
781 if (!rc)
782 return 0;
783
784 /*
785 * The subvolume has reloc tree but the swap is finished, no need to
786 * create/update the dead reloc tree
787 */
788 if (reloc_root_is_dead(root))
789 return 0;
790
791 /*
792 * This is subtle but important. We do not do
793 * record_root_in_transaction for reloc roots, instead we record their
794 * corresponding fs root, and then here we update the last trans for the
795 * reloc root. This means that we have to do this for the entire life
796 * of the reloc root, regardless of which stage of the relocation we are
797 * in.
798 */
799 if (root->reloc_root) {
800 reloc_root = root->reloc_root;
801 btrfs_set_root_last_trans(reloc_root, trans->transid);
802 return 0;
803 }
804
805 /*
806 * We are merging reloc roots, we do not need new reloc trees. Also
807 * reloc trees never need their own reloc tree.
808 */
809 if (!rc->create_reloc_tree || btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID)
810 return 0;
811
812 if (!trans->reloc_reserved) {
813 rsv = trans->block_rsv;
814 trans->block_rsv = rc->block_rsv;
815 clear_rsv = 1;
816 }
817 reloc_root = create_reloc_root(trans, root, btrfs_root_id(root));
818 if (clear_rsv)
819 trans->block_rsv = rsv;
820 if (IS_ERR(reloc_root))
821 return PTR_ERR(reloc_root);
822
823 ret = __add_reloc_root(reloc_root);
824 ASSERT(ret != -EEXIST);
825 if (ret) {
826 /* Pairs with create_reloc_root */
827 btrfs_put_root(reloc_root);
828 return ret;
829 }
830 root->reloc_root = btrfs_grab_root(reloc_root);
831 return 0;
832}
833
834/*
835 * update root item of reloc tree
836 */
837int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
838 struct btrfs_root *root)
839{
840 struct btrfs_fs_info *fs_info = root->fs_info;
841 struct btrfs_root *reloc_root;
842 struct btrfs_root_item *root_item;
843 int ret;
844
845 if (!have_reloc_root(root))
846 return 0;
847
848 reloc_root = root->reloc_root;
849 root_item = &reloc_root->root_item;
850
851 /*
852 * We are probably ok here, but __del_reloc_root() will drop its ref of
853 * the root. We have the ref for root->reloc_root, but just in case
854 * hold it while we update the reloc root.
855 */
856 btrfs_grab_root(reloc_root);
857
858 /* root->reloc_root will stay until current relocation finished */
859 if (fs_info->reloc_ctl && fs_info->reloc_ctl->merge_reloc_tree &&
860 btrfs_root_refs(root_item) == 0) {
861 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
862 /*
863 * Mark the tree as dead before we change reloc_root so
864 * have_reloc_root will not touch it from now on.
865 */
866 smp_wmb();
867 __del_reloc_root(reloc_root);
868 }
869
870 if (reloc_root->commit_root != reloc_root->node) {
871 __update_reloc_root(reloc_root);
872 btrfs_set_root_node(root_item, reloc_root->node);
873 free_extent_buffer(reloc_root->commit_root);
874 reloc_root->commit_root = btrfs_root_node(reloc_root);
875 }
876
877 ret = btrfs_update_root(trans, fs_info->tree_root,
878 &reloc_root->root_key, root_item);
879 btrfs_put_root(reloc_root);
880 return ret;
881}
882
883/*
884 * get new location of data
885 */
886static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
887 u64 bytenr, u64 num_bytes)
888{
889 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
890 struct btrfs_path *path;
891 struct btrfs_file_extent_item *fi;
892 struct extent_buffer *leaf;
893 int ret;
894
895 path = btrfs_alloc_path();
896 if (!path)
897 return -ENOMEM;
898
899 bytenr -= BTRFS_I(reloc_inode)->reloc_block_group_start;
900 ret = btrfs_lookup_file_extent(NULL, root, path,
901 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
902 if (ret < 0)
903 goto out;
904 if (ret > 0) {
905 ret = -ENOENT;
906 goto out;
907 }
908
909 leaf = path->nodes[0];
910 fi = btrfs_item_ptr(leaf, path->slots[0],
911 struct btrfs_file_extent_item);
912
913 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
914 btrfs_file_extent_compression(leaf, fi) ||
915 btrfs_file_extent_encryption(leaf, fi) ||
916 btrfs_file_extent_other_encoding(leaf, fi));
917
918 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
919 ret = -EINVAL;
920 goto out;
921 }
922
923 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
924 ret = 0;
925out:
926 btrfs_free_path(path);
927 return ret;
928}
929
930/*
931 * update file extent items in the tree leaf to point to
932 * the new locations.
933 */
934static noinline_for_stack
935int replace_file_extents(struct btrfs_trans_handle *trans,
936 struct reloc_control *rc,
937 struct btrfs_root *root,
938 struct extent_buffer *leaf)
939{
940 struct btrfs_fs_info *fs_info = root->fs_info;
941 struct btrfs_key key;
942 struct btrfs_file_extent_item *fi;
943 struct btrfs_inode *inode = NULL;
944 u64 parent;
945 u64 bytenr;
946 u64 new_bytenr = 0;
947 u64 num_bytes;
948 u64 end;
949 u32 nritems;
950 u32 i;
951 int ret = 0;
952 int first = 1;
953 int dirty = 0;
954
955 if (rc->stage != UPDATE_DATA_PTRS)
956 return 0;
957
958 /* reloc trees always use full backref */
959 if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID)
960 parent = leaf->start;
961 else
962 parent = 0;
963
964 nritems = btrfs_header_nritems(leaf);
965 for (i = 0; i < nritems; i++) {
966 struct btrfs_ref ref = { 0 };
967
968 cond_resched();
969 btrfs_item_key_to_cpu(leaf, &key, i);
970 if (key.type != BTRFS_EXTENT_DATA_KEY)
971 continue;
972 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
973 if (btrfs_file_extent_type(leaf, fi) ==
974 BTRFS_FILE_EXTENT_INLINE)
975 continue;
976 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
977 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
978 if (bytenr == 0)
979 continue;
980 if (!in_range(bytenr, rc->block_group->start,
981 rc->block_group->length))
982 continue;
983
984 /*
985 * if we are modifying block in fs tree, wait for read_folio
986 * to complete and drop the extent cache
987 */
988 if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID) {
989 if (first) {
990 inode = btrfs_find_first_inode(root, key.objectid);
991 first = 0;
992 } else if (inode && btrfs_ino(inode) < key.objectid) {
993 btrfs_add_delayed_iput(inode);
994 inode = btrfs_find_first_inode(root, key.objectid);
995 }
996 if (inode && btrfs_ino(inode) == key.objectid) {
997 struct extent_state *cached_state = NULL;
998
999 end = key.offset +
1000 btrfs_file_extent_num_bytes(leaf, fi);
1001 WARN_ON(!IS_ALIGNED(key.offset,
1002 fs_info->sectorsize));
1003 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1004 end--;
1005 /* Take mmap lock to serialize with reflinks. */
1006 if (!down_read_trylock(&inode->i_mmap_lock))
1007 continue;
1008 ret = try_lock_extent(&inode->io_tree, key.offset,
1009 end, &cached_state);
1010 if (!ret) {
1011 up_read(&inode->i_mmap_lock);
1012 continue;
1013 }
1014
1015 btrfs_drop_extent_map_range(inode, key.offset, end, true);
1016 unlock_extent(&inode->io_tree, key.offset, end,
1017 &cached_state);
1018 up_read(&inode->i_mmap_lock);
1019 }
1020 }
1021
1022 ret = get_new_location(rc->data_inode, &new_bytenr,
1023 bytenr, num_bytes);
1024 if (ret) {
1025 /*
1026 * Don't have to abort since we've not changed anything
1027 * in the file extent yet.
1028 */
1029 break;
1030 }
1031
1032 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1033 dirty = 1;
1034
1035 key.offset -= btrfs_file_extent_offset(leaf, fi);
1036 ref.action = BTRFS_ADD_DELAYED_REF;
1037 ref.bytenr = new_bytenr;
1038 ref.num_bytes = num_bytes;
1039 ref.parent = parent;
1040 ref.owning_root = btrfs_root_id(root);
1041 ref.ref_root = btrfs_header_owner(leaf);
1042 btrfs_init_data_ref(&ref, key.objectid, key.offset,
1043 btrfs_root_id(root), false);
1044 ret = btrfs_inc_extent_ref(trans, &ref);
1045 if (ret) {
1046 btrfs_abort_transaction(trans, ret);
1047 break;
1048 }
1049
1050 ref.action = BTRFS_DROP_DELAYED_REF;
1051 ref.bytenr = bytenr;
1052 ref.num_bytes = num_bytes;
1053 ref.parent = parent;
1054 ref.owning_root = btrfs_root_id(root);
1055 ref.ref_root = btrfs_header_owner(leaf);
1056 btrfs_init_data_ref(&ref, key.objectid, key.offset,
1057 btrfs_root_id(root), false);
1058 ret = btrfs_free_extent(trans, &ref);
1059 if (ret) {
1060 btrfs_abort_transaction(trans, ret);
1061 break;
1062 }
1063 }
1064 if (dirty)
1065 btrfs_mark_buffer_dirty(trans, leaf);
1066 if (inode)
1067 btrfs_add_delayed_iput(inode);
1068 return ret;
1069}
1070
1071static noinline_for_stack int memcmp_node_keys(const struct extent_buffer *eb,
1072 int slot, const struct btrfs_path *path,
1073 int level)
1074{
1075 struct btrfs_disk_key key1;
1076 struct btrfs_disk_key key2;
1077 btrfs_node_key(eb, &key1, slot);
1078 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1079 return memcmp(&key1, &key2, sizeof(key1));
1080}
1081
1082/*
1083 * try to replace tree blocks in fs tree with the new blocks
1084 * in reloc tree. tree blocks haven't been modified since the
1085 * reloc tree was create can be replaced.
1086 *
1087 * if a block was replaced, level of the block + 1 is returned.
1088 * if no block got replaced, 0 is returned. if there are other
1089 * errors, a negative error number is returned.
1090 */
1091static noinline_for_stack
1092int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1093 struct btrfs_root *dest, struct btrfs_root *src,
1094 struct btrfs_path *path, struct btrfs_key *next_key,
1095 int lowest_level, int max_level)
1096{
1097 struct btrfs_fs_info *fs_info = dest->fs_info;
1098 struct extent_buffer *eb;
1099 struct extent_buffer *parent;
1100 struct btrfs_ref ref = { 0 };
1101 struct btrfs_key key;
1102 u64 old_bytenr;
1103 u64 new_bytenr;
1104 u64 old_ptr_gen;
1105 u64 new_ptr_gen;
1106 u64 last_snapshot;
1107 u32 blocksize;
1108 int cow = 0;
1109 int level;
1110 int ret;
1111 int slot;
1112
1113 ASSERT(btrfs_root_id(src) == BTRFS_TREE_RELOC_OBJECTID);
1114 ASSERT(btrfs_root_id(dest) != BTRFS_TREE_RELOC_OBJECTID);
1115
1116 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1117again:
1118 slot = path->slots[lowest_level];
1119 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1120
1121 eb = btrfs_lock_root_node(dest);
1122 level = btrfs_header_level(eb);
1123
1124 if (level < lowest_level) {
1125 btrfs_tree_unlock(eb);
1126 free_extent_buffer(eb);
1127 return 0;
1128 }
1129
1130 if (cow) {
1131 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1132 BTRFS_NESTING_COW);
1133 if (ret) {
1134 btrfs_tree_unlock(eb);
1135 free_extent_buffer(eb);
1136 return ret;
1137 }
1138 }
1139
1140 if (next_key) {
1141 next_key->objectid = (u64)-1;
1142 next_key->type = (u8)-1;
1143 next_key->offset = (u64)-1;
1144 }
1145
1146 parent = eb;
1147 while (1) {
1148 level = btrfs_header_level(parent);
1149 ASSERT(level >= lowest_level);
1150
1151 ret = btrfs_bin_search(parent, 0, &key, &slot);
1152 if (ret < 0)
1153 break;
1154 if (ret && slot > 0)
1155 slot--;
1156
1157 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1158 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1159
1160 old_bytenr = btrfs_node_blockptr(parent, slot);
1161 blocksize = fs_info->nodesize;
1162 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1163
1164 if (level <= max_level) {
1165 eb = path->nodes[level];
1166 new_bytenr = btrfs_node_blockptr(eb,
1167 path->slots[level]);
1168 new_ptr_gen = btrfs_node_ptr_generation(eb,
1169 path->slots[level]);
1170 } else {
1171 new_bytenr = 0;
1172 new_ptr_gen = 0;
1173 }
1174
1175 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1176 ret = level;
1177 break;
1178 }
1179
1180 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1181 memcmp_node_keys(parent, slot, path, level)) {
1182 if (level <= lowest_level) {
1183 ret = 0;
1184 break;
1185 }
1186
1187 eb = btrfs_read_node_slot(parent, slot);
1188 if (IS_ERR(eb)) {
1189 ret = PTR_ERR(eb);
1190 break;
1191 }
1192 btrfs_tree_lock(eb);
1193 if (cow) {
1194 ret = btrfs_cow_block(trans, dest, eb, parent,
1195 slot, &eb,
1196 BTRFS_NESTING_COW);
1197 if (ret) {
1198 btrfs_tree_unlock(eb);
1199 free_extent_buffer(eb);
1200 break;
1201 }
1202 }
1203
1204 btrfs_tree_unlock(parent);
1205 free_extent_buffer(parent);
1206
1207 parent = eb;
1208 continue;
1209 }
1210
1211 if (!cow) {
1212 btrfs_tree_unlock(parent);
1213 free_extent_buffer(parent);
1214 cow = 1;
1215 goto again;
1216 }
1217
1218 btrfs_node_key_to_cpu(path->nodes[level], &key,
1219 path->slots[level]);
1220 btrfs_release_path(path);
1221
1222 path->lowest_level = level;
1223 set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1224 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1225 clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1226 path->lowest_level = 0;
1227 if (ret) {
1228 if (ret > 0)
1229 ret = -ENOENT;
1230 break;
1231 }
1232
1233 /*
1234 * Info qgroup to trace both subtrees.
1235 *
1236 * We must trace both trees.
1237 * 1) Tree reloc subtree
1238 * If not traced, we will leak data numbers
1239 * 2) Fs subtree
1240 * If not traced, we will double count old data
1241 *
1242 * We don't scan the subtree right now, but only record
1243 * the swapped tree blocks.
1244 * The real subtree rescan is delayed until we have new
1245 * CoW on the subtree root node before transaction commit.
1246 */
1247 ret = btrfs_qgroup_add_swapped_blocks(dest,
1248 rc->block_group, parent, slot,
1249 path->nodes[level], path->slots[level],
1250 last_snapshot);
1251 if (ret < 0)
1252 break;
1253 /*
1254 * swap blocks in fs tree and reloc tree.
1255 */
1256 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1257 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1258 btrfs_mark_buffer_dirty(trans, parent);
1259
1260 btrfs_set_node_blockptr(path->nodes[level],
1261 path->slots[level], old_bytenr);
1262 btrfs_set_node_ptr_generation(path->nodes[level],
1263 path->slots[level], old_ptr_gen);
1264 btrfs_mark_buffer_dirty(trans, path->nodes[level]);
1265
1266 ref.action = BTRFS_ADD_DELAYED_REF;
1267 ref.bytenr = old_bytenr;
1268 ref.num_bytes = blocksize;
1269 ref.parent = path->nodes[level]->start;
1270 ref.owning_root = btrfs_root_id(src);
1271 ref.ref_root = btrfs_root_id(src);
1272 btrfs_init_tree_ref(&ref, level - 1, 0, true);
1273 ret = btrfs_inc_extent_ref(trans, &ref);
1274 if (ret) {
1275 btrfs_abort_transaction(trans, ret);
1276 break;
1277 }
1278
1279 ref.action = BTRFS_ADD_DELAYED_REF;
1280 ref.bytenr = new_bytenr;
1281 ref.num_bytes = blocksize;
1282 ref.parent = 0;
1283 ref.owning_root = btrfs_root_id(dest);
1284 ref.ref_root = btrfs_root_id(dest);
1285 btrfs_init_tree_ref(&ref, level - 1, 0, true);
1286 ret = btrfs_inc_extent_ref(trans, &ref);
1287 if (ret) {
1288 btrfs_abort_transaction(trans, ret);
1289 break;
1290 }
1291
1292 /* We don't know the real owning_root, use 0. */
1293 ref.action = BTRFS_DROP_DELAYED_REF;
1294 ref.bytenr = new_bytenr;
1295 ref.num_bytes = blocksize;
1296 ref.parent = path->nodes[level]->start;
1297 ref.owning_root = 0;
1298 ref.ref_root = btrfs_root_id(src);
1299 btrfs_init_tree_ref(&ref, level - 1, 0, true);
1300 ret = btrfs_free_extent(trans, &ref);
1301 if (ret) {
1302 btrfs_abort_transaction(trans, ret);
1303 break;
1304 }
1305
1306 /* We don't know the real owning_root, use 0. */
1307 ref.action = BTRFS_DROP_DELAYED_REF;
1308 ref.bytenr = old_bytenr;
1309 ref.num_bytes = blocksize;
1310 ref.parent = 0;
1311 ref.owning_root = 0;
1312 ref.ref_root = btrfs_root_id(dest);
1313 btrfs_init_tree_ref(&ref, level - 1, 0, true);
1314 ret = btrfs_free_extent(trans, &ref);
1315 if (ret) {
1316 btrfs_abort_transaction(trans, ret);
1317 break;
1318 }
1319
1320 btrfs_unlock_up_safe(path, 0);
1321
1322 ret = level;
1323 break;
1324 }
1325 btrfs_tree_unlock(parent);
1326 free_extent_buffer(parent);
1327 return ret;
1328}
1329
1330/*
1331 * helper to find next relocated block in reloc tree
1332 */
1333static noinline_for_stack
1334int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1335 int *level)
1336{
1337 struct extent_buffer *eb;
1338 int i;
1339 u64 last_snapshot;
1340 u32 nritems;
1341
1342 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1343
1344 for (i = 0; i < *level; i++) {
1345 free_extent_buffer(path->nodes[i]);
1346 path->nodes[i] = NULL;
1347 }
1348
1349 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1350 eb = path->nodes[i];
1351 nritems = btrfs_header_nritems(eb);
1352 while (path->slots[i] + 1 < nritems) {
1353 path->slots[i]++;
1354 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1355 last_snapshot)
1356 continue;
1357
1358 *level = i;
1359 return 0;
1360 }
1361 free_extent_buffer(path->nodes[i]);
1362 path->nodes[i] = NULL;
1363 }
1364 return 1;
1365}
1366
1367/*
1368 * walk down reloc tree to find relocated block of lowest level
1369 */
1370static noinline_for_stack
1371int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1372 int *level)
1373{
1374 struct extent_buffer *eb = NULL;
1375 int i;
1376 u64 ptr_gen = 0;
1377 u64 last_snapshot;
1378 u32 nritems;
1379
1380 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1381
1382 for (i = *level; i > 0; i--) {
1383 eb = path->nodes[i];
1384 nritems = btrfs_header_nritems(eb);
1385 while (path->slots[i] < nritems) {
1386 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1387 if (ptr_gen > last_snapshot)
1388 break;
1389 path->slots[i]++;
1390 }
1391 if (path->slots[i] >= nritems) {
1392 if (i == *level)
1393 break;
1394 *level = i + 1;
1395 return 0;
1396 }
1397 if (i == 1) {
1398 *level = i;
1399 return 0;
1400 }
1401
1402 eb = btrfs_read_node_slot(eb, path->slots[i]);
1403 if (IS_ERR(eb))
1404 return PTR_ERR(eb);
1405 BUG_ON(btrfs_header_level(eb) != i - 1);
1406 path->nodes[i - 1] = eb;
1407 path->slots[i - 1] = 0;
1408 }
1409 return 1;
1410}
1411
1412/*
1413 * invalidate extent cache for file extents whose key in range of
1414 * [min_key, max_key)
1415 */
1416static int invalidate_extent_cache(struct btrfs_root *root,
1417 const struct btrfs_key *min_key,
1418 const struct btrfs_key *max_key)
1419{
1420 struct btrfs_fs_info *fs_info = root->fs_info;
1421 struct btrfs_inode *inode = NULL;
1422 u64 objectid;
1423 u64 start, end;
1424 u64 ino;
1425
1426 objectid = min_key->objectid;
1427 while (1) {
1428 struct extent_state *cached_state = NULL;
1429
1430 cond_resched();
1431 if (inode)
1432 iput(&inode->vfs_inode);
1433
1434 if (objectid > max_key->objectid)
1435 break;
1436
1437 inode = btrfs_find_first_inode(root, objectid);
1438 if (!inode)
1439 break;
1440 ino = btrfs_ino(inode);
1441
1442 if (ino > max_key->objectid) {
1443 iput(&inode->vfs_inode);
1444 break;
1445 }
1446
1447 objectid = ino + 1;
1448 if (!S_ISREG(inode->vfs_inode.i_mode))
1449 continue;
1450
1451 if (unlikely(min_key->objectid == ino)) {
1452 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1453 continue;
1454 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1455 start = 0;
1456 else {
1457 start = min_key->offset;
1458 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1459 }
1460 } else {
1461 start = 0;
1462 }
1463
1464 if (unlikely(max_key->objectid == ino)) {
1465 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1466 continue;
1467 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1468 end = (u64)-1;
1469 } else {
1470 if (max_key->offset == 0)
1471 continue;
1472 end = max_key->offset;
1473 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1474 end--;
1475 }
1476 } else {
1477 end = (u64)-1;
1478 }
1479
1480 /* the lock_extent waits for read_folio to complete */
1481 lock_extent(&inode->io_tree, start, end, &cached_state);
1482 btrfs_drop_extent_map_range(inode, start, end, true);
1483 unlock_extent(&inode->io_tree, start, end, &cached_state);
1484 }
1485 return 0;
1486}
1487
1488static int find_next_key(struct btrfs_path *path, int level,
1489 struct btrfs_key *key)
1490
1491{
1492 while (level < BTRFS_MAX_LEVEL) {
1493 if (!path->nodes[level])
1494 break;
1495 if (path->slots[level] + 1 <
1496 btrfs_header_nritems(path->nodes[level])) {
1497 btrfs_node_key_to_cpu(path->nodes[level], key,
1498 path->slots[level] + 1);
1499 return 0;
1500 }
1501 level++;
1502 }
1503 return 1;
1504}
1505
1506/*
1507 * Insert current subvolume into reloc_control::dirty_subvol_roots
1508 */
1509static int insert_dirty_subvol(struct btrfs_trans_handle *trans,
1510 struct reloc_control *rc,
1511 struct btrfs_root *root)
1512{
1513 struct btrfs_root *reloc_root = root->reloc_root;
1514 struct btrfs_root_item *reloc_root_item;
1515 int ret;
1516
1517 /* @root must be a subvolume tree root with a valid reloc tree */
1518 ASSERT(btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID);
1519 ASSERT(reloc_root);
1520
1521 reloc_root_item = &reloc_root->root_item;
1522 memset(&reloc_root_item->drop_progress, 0,
1523 sizeof(reloc_root_item->drop_progress));
1524 btrfs_set_root_drop_level(reloc_root_item, 0);
1525 btrfs_set_root_refs(reloc_root_item, 0);
1526 ret = btrfs_update_reloc_root(trans, root);
1527 if (ret)
1528 return ret;
1529
1530 if (list_empty(&root->reloc_dirty_list)) {
1531 btrfs_grab_root(root);
1532 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1533 }
1534
1535 return 0;
1536}
1537
1538static int clean_dirty_subvols(struct reloc_control *rc)
1539{
1540 struct btrfs_root *root;
1541 struct btrfs_root *next;
1542 int ret = 0;
1543 int ret2;
1544
1545 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1546 reloc_dirty_list) {
1547 if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID) {
1548 /* Merged subvolume, cleanup its reloc root */
1549 struct btrfs_root *reloc_root = root->reloc_root;
1550
1551 list_del_init(&root->reloc_dirty_list);
1552 root->reloc_root = NULL;
1553 /*
1554 * Need barrier to ensure clear_bit() only happens after
1555 * root->reloc_root = NULL. Pairs with have_reloc_root.
1556 */
1557 smp_wmb();
1558 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1559 if (reloc_root) {
1560 /*
1561 * btrfs_drop_snapshot drops our ref we hold for
1562 * ->reloc_root. If it fails however we must
1563 * drop the ref ourselves.
1564 */
1565 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1566 if (ret2 < 0) {
1567 btrfs_put_root(reloc_root);
1568 if (!ret)
1569 ret = ret2;
1570 }
1571 }
1572 btrfs_put_root(root);
1573 } else {
1574 /* Orphan reloc tree, just clean it up */
1575 ret2 = btrfs_drop_snapshot(root, 0, 1);
1576 if (ret2 < 0) {
1577 btrfs_put_root(root);
1578 if (!ret)
1579 ret = ret2;
1580 }
1581 }
1582 }
1583 return ret;
1584}
1585
1586/*
1587 * merge the relocated tree blocks in reloc tree with corresponding
1588 * fs tree.
1589 */
1590static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1591 struct btrfs_root *root)
1592{
1593 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1594 struct btrfs_key key;
1595 struct btrfs_key next_key;
1596 struct btrfs_trans_handle *trans = NULL;
1597 struct btrfs_root *reloc_root;
1598 struct btrfs_root_item *root_item;
1599 struct btrfs_path *path;
1600 struct extent_buffer *leaf;
1601 int reserve_level;
1602 int level;
1603 int max_level;
1604 int replaced = 0;
1605 int ret = 0;
1606 u32 min_reserved;
1607
1608 path = btrfs_alloc_path();
1609 if (!path)
1610 return -ENOMEM;
1611 path->reada = READA_FORWARD;
1612
1613 reloc_root = root->reloc_root;
1614 root_item = &reloc_root->root_item;
1615
1616 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1617 level = btrfs_root_level(root_item);
1618 atomic_inc(&reloc_root->node->refs);
1619 path->nodes[level] = reloc_root->node;
1620 path->slots[level] = 0;
1621 } else {
1622 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1623
1624 level = btrfs_root_drop_level(root_item);
1625 BUG_ON(level == 0);
1626 path->lowest_level = level;
1627 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1628 path->lowest_level = 0;
1629 if (ret < 0) {
1630 btrfs_free_path(path);
1631 return ret;
1632 }
1633
1634 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1635 path->slots[level]);
1636 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1637
1638 btrfs_unlock_up_safe(path, 0);
1639 }
1640
1641 /*
1642 * In merge_reloc_root(), we modify the upper level pointer to swap the
1643 * tree blocks between reloc tree and subvolume tree. Thus for tree
1644 * block COW, we COW at most from level 1 to root level for each tree.
1645 *
1646 * Thus the needed metadata size is at most root_level * nodesize,
1647 * and * 2 since we have two trees to COW.
1648 */
1649 reserve_level = max_t(int, 1, btrfs_root_level(root_item));
1650 min_reserved = fs_info->nodesize * reserve_level * 2;
1651 memset(&next_key, 0, sizeof(next_key));
1652
1653 while (1) {
1654 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
1655 min_reserved,
1656 BTRFS_RESERVE_FLUSH_LIMIT);
1657 if (ret)
1658 goto out;
1659 trans = btrfs_start_transaction(root, 0);
1660 if (IS_ERR(trans)) {
1661 ret = PTR_ERR(trans);
1662 trans = NULL;
1663 goto out;
1664 }
1665
1666 /*
1667 * At this point we no longer have a reloc_control, so we can't
1668 * depend on btrfs_init_reloc_root to update our last_trans.
1669 *
1670 * But that's ok, we started the trans handle on our
1671 * corresponding fs_root, which means it's been added to the
1672 * dirty list. At commit time we'll still call
1673 * btrfs_update_reloc_root() and update our root item
1674 * appropriately.
1675 */
1676 btrfs_set_root_last_trans(reloc_root, trans->transid);
1677 trans->block_rsv = rc->block_rsv;
1678
1679 replaced = 0;
1680 max_level = level;
1681
1682 ret = walk_down_reloc_tree(reloc_root, path, &level);
1683 if (ret < 0)
1684 goto out;
1685 if (ret > 0)
1686 break;
1687
1688 if (!find_next_key(path, level, &key) &&
1689 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1690 ret = 0;
1691 } else {
1692 ret = replace_path(trans, rc, root, reloc_root, path,
1693 &next_key, level, max_level);
1694 }
1695 if (ret < 0)
1696 goto out;
1697 if (ret > 0) {
1698 level = ret;
1699 btrfs_node_key_to_cpu(path->nodes[level], &key,
1700 path->slots[level]);
1701 replaced = 1;
1702 }
1703
1704 ret = walk_up_reloc_tree(reloc_root, path, &level);
1705 if (ret > 0)
1706 break;
1707
1708 BUG_ON(level == 0);
1709 /*
1710 * save the merging progress in the drop_progress.
1711 * this is OK since root refs == 1 in this case.
1712 */
1713 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1714 path->slots[level]);
1715 btrfs_set_root_drop_level(root_item, level);
1716
1717 btrfs_end_transaction_throttle(trans);
1718 trans = NULL;
1719
1720 btrfs_btree_balance_dirty(fs_info);
1721
1722 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1723 invalidate_extent_cache(root, &key, &next_key);
1724 }
1725
1726 /*
1727 * handle the case only one block in the fs tree need to be
1728 * relocated and the block is tree root.
1729 */
1730 leaf = btrfs_lock_root_node(root);
1731 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1732 BTRFS_NESTING_COW);
1733 btrfs_tree_unlock(leaf);
1734 free_extent_buffer(leaf);
1735out:
1736 btrfs_free_path(path);
1737
1738 if (ret == 0) {
1739 ret = insert_dirty_subvol(trans, rc, root);
1740 if (ret)
1741 btrfs_abort_transaction(trans, ret);
1742 }
1743
1744 if (trans)
1745 btrfs_end_transaction_throttle(trans);
1746
1747 btrfs_btree_balance_dirty(fs_info);
1748
1749 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1750 invalidate_extent_cache(root, &key, &next_key);
1751
1752 return ret;
1753}
1754
1755static noinline_for_stack
1756int prepare_to_merge(struct reloc_control *rc, int err)
1757{
1758 struct btrfs_root *root = rc->extent_root;
1759 struct btrfs_fs_info *fs_info = root->fs_info;
1760 struct btrfs_root *reloc_root;
1761 struct btrfs_trans_handle *trans;
1762 LIST_HEAD(reloc_roots);
1763 u64 num_bytes = 0;
1764 int ret;
1765
1766 mutex_lock(&fs_info->reloc_mutex);
1767 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1768 rc->merging_rsv_size += rc->nodes_relocated * 2;
1769 mutex_unlock(&fs_info->reloc_mutex);
1770
1771again:
1772 if (!err) {
1773 num_bytes = rc->merging_rsv_size;
1774 ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes,
1775 BTRFS_RESERVE_FLUSH_ALL);
1776 if (ret)
1777 err = ret;
1778 }
1779
1780 trans = btrfs_join_transaction(rc->extent_root);
1781 if (IS_ERR(trans)) {
1782 if (!err)
1783 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1784 num_bytes, NULL);
1785 return PTR_ERR(trans);
1786 }
1787
1788 if (!err) {
1789 if (num_bytes != rc->merging_rsv_size) {
1790 btrfs_end_transaction(trans);
1791 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1792 num_bytes, NULL);
1793 goto again;
1794 }
1795 }
1796
1797 rc->merge_reloc_tree = true;
1798
1799 while (!list_empty(&rc->reloc_roots)) {
1800 reloc_root = list_entry(rc->reloc_roots.next,
1801 struct btrfs_root, root_list);
1802 list_del_init(&reloc_root->root_list);
1803
1804 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1805 false);
1806 if (IS_ERR(root)) {
1807 /*
1808 * Even if we have an error we need this reloc root
1809 * back on our list so we can clean up properly.
1810 */
1811 list_add(&reloc_root->root_list, &reloc_roots);
1812 btrfs_abort_transaction(trans, (int)PTR_ERR(root));
1813 if (!err)
1814 err = PTR_ERR(root);
1815 break;
1816 }
1817
1818 if (unlikely(root->reloc_root != reloc_root)) {
1819 if (root->reloc_root) {
1820 btrfs_err(fs_info,
1821"reloc tree mismatch, root %lld has reloc root key (%lld %u %llu) gen %llu, expect reloc root key (%lld %u %llu) gen %llu",
1822 btrfs_root_id(root),
1823 btrfs_root_id(root->reloc_root),
1824 root->reloc_root->root_key.type,
1825 root->reloc_root->root_key.offset,
1826 btrfs_root_generation(
1827 &root->reloc_root->root_item),
1828 btrfs_root_id(reloc_root),
1829 reloc_root->root_key.type,
1830 reloc_root->root_key.offset,
1831 btrfs_root_generation(
1832 &reloc_root->root_item));
1833 } else {
1834 btrfs_err(fs_info,
1835"reloc tree mismatch, root %lld has no reloc root, expect reloc root key (%lld %u %llu) gen %llu",
1836 btrfs_root_id(root),
1837 btrfs_root_id(reloc_root),
1838 reloc_root->root_key.type,
1839 reloc_root->root_key.offset,
1840 btrfs_root_generation(
1841 &reloc_root->root_item));
1842 }
1843 list_add(&reloc_root->root_list, &reloc_roots);
1844 btrfs_put_root(root);
1845 btrfs_abort_transaction(trans, -EUCLEAN);
1846 if (!err)
1847 err = -EUCLEAN;
1848 break;
1849 }
1850
1851 /*
1852 * set reference count to 1, so btrfs_recover_relocation
1853 * knows it should resumes merging
1854 */
1855 if (!err)
1856 btrfs_set_root_refs(&reloc_root->root_item, 1);
1857 ret = btrfs_update_reloc_root(trans, root);
1858
1859 /*
1860 * Even if we have an error we need this reloc root back on our
1861 * list so we can clean up properly.
1862 */
1863 list_add(&reloc_root->root_list, &reloc_roots);
1864 btrfs_put_root(root);
1865
1866 if (ret) {
1867 btrfs_abort_transaction(trans, ret);
1868 if (!err)
1869 err = ret;
1870 break;
1871 }
1872 }
1873
1874 list_splice(&reloc_roots, &rc->reloc_roots);
1875
1876 if (!err)
1877 err = btrfs_commit_transaction(trans);
1878 else
1879 btrfs_end_transaction(trans);
1880 return err;
1881}
1882
1883static noinline_for_stack
1884void free_reloc_roots(struct list_head *list)
1885{
1886 struct btrfs_root *reloc_root, *tmp;
1887
1888 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1889 __del_reloc_root(reloc_root);
1890}
1891
1892static noinline_for_stack
1893void merge_reloc_roots(struct reloc_control *rc)
1894{
1895 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1896 struct btrfs_root *root;
1897 struct btrfs_root *reloc_root;
1898 LIST_HEAD(reloc_roots);
1899 int found = 0;
1900 int ret = 0;
1901again:
1902 root = rc->extent_root;
1903
1904 /*
1905 * this serializes us with btrfs_record_root_in_transaction,
1906 * we have to make sure nobody is in the middle of
1907 * adding their roots to the list while we are
1908 * doing this splice
1909 */
1910 mutex_lock(&fs_info->reloc_mutex);
1911 list_splice_init(&rc->reloc_roots, &reloc_roots);
1912 mutex_unlock(&fs_info->reloc_mutex);
1913
1914 while (!list_empty(&reloc_roots)) {
1915 found = 1;
1916 reloc_root = list_entry(reloc_roots.next,
1917 struct btrfs_root, root_list);
1918
1919 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1920 false);
1921 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
1922 if (WARN_ON(IS_ERR(root))) {
1923 /*
1924 * For recovery we read the fs roots on mount,
1925 * and if we didn't find the root then we marked
1926 * the reloc root as a garbage root. For normal
1927 * relocation obviously the root should exist in
1928 * memory. However there's no reason we can't
1929 * handle the error properly here just in case.
1930 */
1931 ret = PTR_ERR(root);
1932 goto out;
1933 }
1934 if (WARN_ON(root->reloc_root != reloc_root)) {
1935 /*
1936 * This can happen if on-disk metadata has some
1937 * corruption, e.g. bad reloc tree key offset.
1938 */
1939 ret = -EINVAL;
1940 goto out;
1941 }
1942 ret = merge_reloc_root(rc, root);
1943 btrfs_put_root(root);
1944 if (ret) {
1945 if (list_empty(&reloc_root->root_list))
1946 list_add_tail(&reloc_root->root_list,
1947 &reloc_roots);
1948 goto out;
1949 }
1950 } else {
1951 if (!IS_ERR(root)) {
1952 if (root->reloc_root == reloc_root) {
1953 root->reloc_root = NULL;
1954 btrfs_put_root(reloc_root);
1955 }
1956 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
1957 &root->state);
1958 btrfs_put_root(root);
1959 }
1960
1961 list_del_init(&reloc_root->root_list);
1962 /* Don't forget to queue this reloc root for cleanup */
1963 list_add_tail(&reloc_root->reloc_dirty_list,
1964 &rc->dirty_subvol_roots);
1965 }
1966 }
1967
1968 if (found) {
1969 found = 0;
1970 goto again;
1971 }
1972out:
1973 if (ret) {
1974 btrfs_handle_fs_error(fs_info, ret, NULL);
1975 free_reloc_roots(&reloc_roots);
1976
1977 /* new reloc root may be added */
1978 mutex_lock(&fs_info->reloc_mutex);
1979 list_splice_init(&rc->reloc_roots, &reloc_roots);
1980 mutex_unlock(&fs_info->reloc_mutex);
1981 free_reloc_roots(&reloc_roots);
1982 }
1983
1984 /*
1985 * We used to have
1986 *
1987 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
1988 *
1989 * here, but it's wrong. If we fail to start the transaction in
1990 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
1991 * have actually been removed from the reloc_root_tree rb tree. This is
1992 * fine because we're bailing here, and we hold a reference on the root
1993 * for the list that holds it, so these roots will be cleaned up when we
1994 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
1995 * will be cleaned up on unmount.
1996 *
1997 * The remaining nodes will be cleaned up by free_reloc_control.
1998 */
1999}
2000
2001static void free_block_list(struct rb_root *blocks)
2002{
2003 struct tree_block *block;
2004 struct rb_node *rb_node;
2005 while ((rb_node = rb_first(blocks))) {
2006 block = rb_entry(rb_node, struct tree_block, rb_node);
2007 rb_erase(rb_node, blocks);
2008 kfree(block);
2009 }
2010}
2011
2012static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2013 struct btrfs_root *reloc_root)
2014{
2015 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2016 struct btrfs_root *root;
2017 int ret;
2018
2019 if (btrfs_get_root_last_trans(reloc_root) == trans->transid)
2020 return 0;
2021
2022 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2023
2024 /*
2025 * This should succeed, since we can't have a reloc root without having
2026 * already looked up the actual root and created the reloc root for this
2027 * root.
2028 *
2029 * However if there's some sort of corruption where we have a ref to a
2030 * reloc root without a corresponding root this could return ENOENT.
2031 */
2032 if (IS_ERR(root)) {
2033 ASSERT(0);
2034 return PTR_ERR(root);
2035 }
2036 if (root->reloc_root != reloc_root) {
2037 ASSERT(0);
2038 btrfs_err(fs_info,
2039 "root %llu has two reloc roots associated with it",
2040 reloc_root->root_key.offset);
2041 btrfs_put_root(root);
2042 return -EUCLEAN;
2043 }
2044 ret = btrfs_record_root_in_trans(trans, root);
2045 btrfs_put_root(root);
2046
2047 return ret;
2048}
2049
2050static noinline_for_stack
2051struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2052 struct reloc_control *rc,
2053 struct btrfs_backref_node *node,
2054 struct btrfs_backref_edge *edges[])
2055{
2056 struct btrfs_backref_node *next;
2057 struct btrfs_root *root;
2058 int index = 0;
2059 int ret;
2060
2061 next = node;
2062 while (1) {
2063 cond_resched();
2064 next = walk_up_backref(next, edges, &index);
2065 root = next->root;
2066
2067 /*
2068 * If there is no root, then our references for this block are
2069 * incomplete, as we should be able to walk all the way up to a
2070 * block that is owned by a root.
2071 *
2072 * This path is only for SHAREABLE roots, so if we come upon a
2073 * non-SHAREABLE root then we have backrefs that resolve
2074 * improperly.
2075 *
2076 * Both of these cases indicate file system corruption, or a bug
2077 * in the backref walking code.
2078 */
2079 if (!root) {
2080 ASSERT(0);
2081 btrfs_err(trans->fs_info,
2082 "bytenr %llu doesn't have a backref path ending in a root",
2083 node->bytenr);
2084 return ERR_PTR(-EUCLEAN);
2085 }
2086 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2087 ASSERT(0);
2088 btrfs_err(trans->fs_info,
2089 "bytenr %llu has multiple refs with one ending in a non-shareable root",
2090 node->bytenr);
2091 return ERR_PTR(-EUCLEAN);
2092 }
2093
2094 if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID) {
2095 ret = record_reloc_root_in_trans(trans, root);
2096 if (ret)
2097 return ERR_PTR(ret);
2098 break;
2099 }
2100
2101 ret = btrfs_record_root_in_trans(trans, root);
2102 if (ret)
2103 return ERR_PTR(ret);
2104 root = root->reloc_root;
2105
2106 /*
2107 * We could have raced with another thread which failed, so
2108 * root->reloc_root may not be set, return ENOENT in this case.
2109 */
2110 if (!root)
2111 return ERR_PTR(-ENOENT);
2112
2113 if (next->new_bytenr != root->node->start) {
2114 /*
2115 * We just created the reloc root, so we shouldn't have
2116 * ->new_bytenr set and this shouldn't be in the changed
2117 * list. If it is then we have multiple roots pointing
2118 * at the same bytenr which indicates corruption, or
2119 * we've made a mistake in the backref walking code.
2120 */
2121 ASSERT(next->new_bytenr == 0);
2122 ASSERT(list_empty(&next->list));
2123 if (next->new_bytenr || !list_empty(&next->list)) {
2124 btrfs_err(trans->fs_info,
2125 "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
2126 node->bytenr, next->bytenr);
2127 return ERR_PTR(-EUCLEAN);
2128 }
2129
2130 next->new_bytenr = root->node->start;
2131 btrfs_put_root(next->root);
2132 next->root = btrfs_grab_root(root);
2133 ASSERT(next->root);
2134 list_add_tail(&next->list,
2135 &rc->backref_cache.changed);
2136 mark_block_processed(rc, next);
2137 break;
2138 }
2139
2140 WARN_ON(1);
2141 root = NULL;
2142 next = walk_down_backref(edges, &index);
2143 if (!next || next->level <= node->level)
2144 break;
2145 }
2146 if (!root) {
2147 /*
2148 * This can happen if there's fs corruption or if there's a bug
2149 * in the backref lookup code.
2150 */
2151 ASSERT(0);
2152 return ERR_PTR(-ENOENT);
2153 }
2154
2155 next = node;
2156 /* setup backref node path for btrfs_reloc_cow_block */
2157 while (1) {
2158 rc->backref_cache.path[next->level] = next;
2159 if (--index < 0)
2160 break;
2161 next = edges[index]->node[UPPER];
2162 }
2163 return root;
2164}
2165
2166/*
2167 * Select a tree root for relocation.
2168 *
2169 * Return NULL if the block is not shareable. We should use do_relocation() in
2170 * this case.
2171 *
2172 * Return a tree root pointer if the block is shareable.
2173 * Return -ENOENT if the block is root of reloc tree.
2174 */
2175static noinline_for_stack
2176struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2177{
2178 struct btrfs_backref_node *next;
2179 struct btrfs_root *root;
2180 struct btrfs_root *fs_root = NULL;
2181 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2182 int index = 0;
2183
2184 next = node;
2185 while (1) {
2186 cond_resched();
2187 next = walk_up_backref(next, edges, &index);
2188 root = next->root;
2189
2190 /*
2191 * This can occur if we have incomplete extent refs leading all
2192 * the way up a particular path, in this case return -EUCLEAN.
2193 */
2194 if (!root)
2195 return ERR_PTR(-EUCLEAN);
2196
2197 /* No other choice for non-shareable tree */
2198 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2199 return root;
2200
2201 if (btrfs_root_id(root) != BTRFS_TREE_RELOC_OBJECTID)
2202 fs_root = root;
2203
2204 if (next != node)
2205 return NULL;
2206
2207 next = walk_down_backref(edges, &index);
2208 if (!next || next->level <= node->level)
2209 break;
2210 }
2211
2212 if (!fs_root)
2213 return ERR_PTR(-ENOENT);
2214 return fs_root;
2215}
2216
2217static noinline_for_stack u64 calcu_metadata_size(struct reloc_control *rc,
2218 struct btrfs_backref_node *node)
2219{
2220 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2221 struct btrfs_backref_node *next = node;
2222 struct btrfs_backref_edge *edge;
2223 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2224 u64 num_bytes = 0;
2225 int index = 0;
2226
2227 BUG_ON(node->processed);
2228
2229 while (next) {
2230 cond_resched();
2231 while (1) {
2232 if (next->processed)
2233 break;
2234
2235 num_bytes += fs_info->nodesize;
2236
2237 if (list_empty(&next->upper))
2238 break;
2239
2240 edge = list_entry(next->upper.next,
2241 struct btrfs_backref_edge, list[LOWER]);
2242 edges[index++] = edge;
2243 next = edge->node[UPPER];
2244 }
2245 next = walk_down_backref(edges, &index);
2246 }
2247 return num_bytes;
2248}
2249
2250static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2251 struct reloc_control *rc,
2252 struct btrfs_backref_node *node)
2253{
2254 struct btrfs_root *root = rc->extent_root;
2255 struct btrfs_fs_info *fs_info = root->fs_info;
2256 u64 num_bytes;
2257 int ret;
2258 u64 tmp;
2259
2260 num_bytes = calcu_metadata_size(rc, node) * 2;
2261
2262 trans->block_rsv = rc->block_rsv;
2263 rc->reserved_bytes += num_bytes;
2264
2265 /*
2266 * We are under a transaction here so we can only do limited flushing.
2267 * If we get an enospc just kick back -EAGAIN so we know to drop the
2268 * transaction and try to refill when we can flush all the things.
2269 */
2270 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
2271 BTRFS_RESERVE_FLUSH_LIMIT);
2272 if (ret) {
2273 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2274 while (tmp <= rc->reserved_bytes)
2275 tmp <<= 1;
2276 /*
2277 * only one thread can access block_rsv at this point,
2278 * so we don't need hold lock to protect block_rsv.
2279 * we expand more reservation size here to allow enough
2280 * space for relocation and we will return earlier in
2281 * enospc case.
2282 */
2283 rc->block_rsv->size = tmp + fs_info->nodesize *
2284 RELOCATION_RESERVED_NODES;
2285 return -EAGAIN;
2286 }
2287
2288 return 0;
2289}
2290
2291/*
2292 * relocate a block tree, and then update pointers in upper level
2293 * blocks that reference the block to point to the new location.
2294 *
2295 * if called by link_to_upper, the block has already been relocated.
2296 * in that case this function just updates pointers.
2297 */
2298static int do_relocation(struct btrfs_trans_handle *trans,
2299 struct reloc_control *rc,
2300 struct btrfs_backref_node *node,
2301 struct btrfs_key *key,
2302 struct btrfs_path *path, int lowest)
2303{
2304 struct btrfs_backref_node *upper;
2305 struct btrfs_backref_edge *edge;
2306 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2307 struct btrfs_root *root;
2308 struct extent_buffer *eb;
2309 u32 blocksize;
2310 u64 bytenr;
2311 int slot;
2312 int ret = 0;
2313
2314 /*
2315 * If we are lowest then this is the first time we're processing this
2316 * block, and thus shouldn't have an eb associated with it yet.
2317 */
2318 ASSERT(!lowest || !node->eb);
2319
2320 path->lowest_level = node->level + 1;
2321 rc->backref_cache.path[node->level] = node;
2322 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2323 cond_resched();
2324
2325 upper = edge->node[UPPER];
2326 root = select_reloc_root(trans, rc, upper, edges);
2327 if (IS_ERR(root)) {
2328 ret = PTR_ERR(root);
2329 goto next;
2330 }
2331
2332 if (upper->eb && !upper->locked) {
2333 if (!lowest) {
2334 ret = btrfs_bin_search(upper->eb, 0, key, &slot);
2335 if (ret < 0)
2336 goto next;
2337 BUG_ON(ret);
2338 bytenr = btrfs_node_blockptr(upper->eb, slot);
2339 if (node->eb->start == bytenr)
2340 goto next;
2341 }
2342 btrfs_backref_drop_node_buffer(upper);
2343 }
2344
2345 if (!upper->eb) {
2346 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2347 if (ret) {
2348 if (ret > 0)
2349 ret = -ENOENT;
2350
2351 btrfs_release_path(path);
2352 break;
2353 }
2354
2355 if (!upper->eb) {
2356 upper->eb = path->nodes[upper->level];
2357 path->nodes[upper->level] = NULL;
2358 } else {
2359 BUG_ON(upper->eb != path->nodes[upper->level]);
2360 }
2361
2362 upper->locked = 1;
2363 path->locks[upper->level] = 0;
2364
2365 slot = path->slots[upper->level];
2366 btrfs_release_path(path);
2367 } else {
2368 ret = btrfs_bin_search(upper->eb, 0, key, &slot);
2369 if (ret < 0)
2370 goto next;
2371 BUG_ON(ret);
2372 }
2373
2374 bytenr = btrfs_node_blockptr(upper->eb, slot);
2375 if (lowest) {
2376 if (bytenr != node->bytenr) {
2377 btrfs_err(root->fs_info,
2378 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2379 bytenr, node->bytenr, slot,
2380 upper->eb->start);
2381 ret = -EIO;
2382 goto next;
2383 }
2384 } else {
2385 if (node->eb->start == bytenr)
2386 goto next;
2387 }
2388
2389 blocksize = root->fs_info->nodesize;
2390 eb = btrfs_read_node_slot(upper->eb, slot);
2391 if (IS_ERR(eb)) {
2392 ret = PTR_ERR(eb);
2393 goto next;
2394 }
2395 btrfs_tree_lock(eb);
2396
2397 if (!node->eb) {
2398 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2399 slot, &eb, BTRFS_NESTING_COW);
2400 btrfs_tree_unlock(eb);
2401 free_extent_buffer(eb);
2402 if (ret < 0)
2403 goto next;
2404 /*
2405 * We've just COWed this block, it should have updated
2406 * the correct backref node entry.
2407 */
2408 ASSERT(node->eb == eb);
2409 } else {
2410 struct btrfs_ref ref = {
2411 .action = BTRFS_ADD_DELAYED_REF,
2412 .bytenr = node->eb->start,
2413 .num_bytes = blocksize,
2414 .parent = upper->eb->start,
2415 .owning_root = btrfs_header_owner(upper->eb),
2416 .ref_root = btrfs_header_owner(upper->eb),
2417 };
2418
2419 btrfs_set_node_blockptr(upper->eb, slot,
2420 node->eb->start);
2421 btrfs_set_node_ptr_generation(upper->eb, slot,
2422 trans->transid);
2423 btrfs_mark_buffer_dirty(trans, upper->eb);
2424
2425 btrfs_init_tree_ref(&ref, node->level,
2426 btrfs_root_id(root), false);
2427 ret = btrfs_inc_extent_ref(trans, &ref);
2428 if (!ret)
2429 ret = btrfs_drop_subtree(trans, root, eb,
2430 upper->eb);
2431 if (ret)
2432 btrfs_abort_transaction(trans, ret);
2433 }
2434next:
2435 if (!upper->pending)
2436 btrfs_backref_drop_node_buffer(upper);
2437 else
2438 btrfs_backref_unlock_node_buffer(upper);
2439 if (ret)
2440 break;
2441 }
2442
2443 if (!ret && node->pending) {
2444 btrfs_backref_drop_node_buffer(node);
2445 list_move_tail(&node->list, &rc->backref_cache.changed);
2446 node->pending = 0;
2447 }
2448
2449 path->lowest_level = 0;
2450
2451 /*
2452 * We should have allocated all of our space in the block rsv and thus
2453 * shouldn't ENOSPC.
2454 */
2455 ASSERT(ret != -ENOSPC);
2456 return ret;
2457}
2458
2459static int link_to_upper(struct btrfs_trans_handle *trans,
2460 struct reloc_control *rc,
2461 struct btrfs_backref_node *node,
2462 struct btrfs_path *path)
2463{
2464 struct btrfs_key key;
2465
2466 btrfs_node_key_to_cpu(node->eb, &key, 0);
2467 return do_relocation(trans, rc, node, &key, path, 0);
2468}
2469
2470static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2471 struct reloc_control *rc,
2472 struct btrfs_path *path, int err)
2473{
2474 LIST_HEAD(list);
2475 struct btrfs_backref_cache *cache = &rc->backref_cache;
2476 struct btrfs_backref_node *node;
2477 int level;
2478 int ret;
2479
2480 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2481 while (!list_empty(&cache->pending[level])) {
2482 node = list_entry(cache->pending[level].next,
2483 struct btrfs_backref_node, list);
2484 list_move_tail(&node->list, &list);
2485 BUG_ON(!node->pending);
2486
2487 if (!err) {
2488 ret = link_to_upper(trans, rc, node, path);
2489 if (ret < 0)
2490 err = ret;
2491 }
2492 }
2493 list_splice_init(&list, &cache->pending[level]);
2494 }
2495 return err;
2496}
2497
2498/*
2499 * mark a block and all blocks directly/indirectly reference the block
2500 * as processed.
2501 */
2502static void update_processed_blocks(struct reloc_control *rc,
2503 struct btrfs_backref_node *node)
2504{
2505 struct btrfs_backref_node *next = node;
2506 struct btrfs_backref_edge *edge;
2507 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2508 int index = 0;
2509
2510 while (next) {
2511 cond_resched();
2512 while (1) {
2513 if (next->processed)
2514 break;
2515
2516 mark_block_processed(rc, next);
2517
2518 if (list_empty(&next->upper))
2519 break;
2520
2521 edge = list_entry(next->upper.next,
2522 struct btrfs_backref_edge, list[LOWER]);
2523 edges[index++] = edge;
2524 next = edge->node[UPPER];
2525 }
2526 next = walk_down_backref(edges, &index);
2527 }
2528}
2529
2530static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2531{
2532 u32 blocksize = rc->extent_root->fs_info->nodesize;
2533
2534 if (test_range_bit(&rc->processed_blocks, bytenr,
2535 bytenr + blocksize - 1, EXTENT_DIRTY, NULL))
2536 return 1;
2537 return 0;
2538}
2539
2540static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2541 struct tree_block *block)
2542{
2543 struct btrfs_tree_parent_check check = {
2544 .level = block->level,
2545 .owner_root = block->owner,
2546 .transid = block->key.offset
2547 };
2548 struct extent_buffer *eb;
2549
2550 eb = read_tree_block(fs_info, block->bytenr, &check);
2551 if (IS_ERR(eb))
2552 return PTR_ERR(eb);
2553 if (!extent_buffer_uptodate(eb)) {
2554 free_extent_buffer(eb);
2555 return -EIO;
2556 }
2557 if (block->level == 0)
2558 btrfs_item_key_to_cpu(eb, &block->key, 0);
2559 else
2560 btrfs_node_key_to_cpu(eb, &block->key, 0);
2561 free_extent_buffer(eb);
2562 block->key_ready = true;
2563 return 0;
2564}
2565
2566/*
2567 * helper function to relocate a tree block
2568 */
2569static int relocate_tree_block(struct btrfs_trans_handle *trans,
2570 struct reloc_control *rc,
2571 struct btrfs_backref_node *node,
2572 struct btrfs_key *key,
2573 struct btrfs_path *path)
2574{
2575 struct btrfs_root *root;
2576 int ret = 0;
2577
2578 if (!node)
2579 return 0;
2580
2581 /*
2582 * If we fail here we want to drop our backref_node because we are going
2583 * to start over and regenerate the tree for it.
2584 */
2585 ret = reserve_metadata_space(trans, rc, node);
2586 if (ret)
2587 goto out;
2588
2589 BUG_ON(node->processed);
2590 root = select_one_root(node);
2591 if (IS_ERR(root)) {
2592 ret = PTR_ERR(root);
2593
2594 /* See explanation in select_one_root for the -EUCLEAN case. */
2595 ASSERT(ret == -ENOENT);
2596 if (ret == -ENOENT) {
2597 ret = 0;
2598 update_processed_blocks(rc, node);
2599 }
2600 goto out;
2601 }
2602
2603 if (root) {
2604 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2605 /*
2606 * This block was the root block of a root, and this is
2607 * the first time we're processing the block and thus it
2608 * should not have had the ->new_bytenr modified and
2609 * should have not been included on the changed list.
2610 *
2611 * However in the case of corruption we could have
2612 * multiple refs pointing to the same block improperly,
2613 * and thus we would trip over these checks. ASSERT()
2614 * for the developer case, because it could indicate a
2615 * bug in the backref code, however error out for a
2616 * normal user in the case of corruption.
2617 */
2618 ASSERT(node->new_bytenr == 0);
2619 ASSERT(list_empty(&node->list));
2620 if (node->new_bytenr || !list_empty(&node->list)) {
2621 btrfs_err(root->fs_info,
2622 "bytenr %llu has improper references to it",
2623 node->bytenr);
2624 ret = -EUCLEAN;
2625 goto out;
2626 }
2627 ret = btrfs_record_root_in_trans(trans, root);
2628 if (ret)
2629 goto out;
2630 /*
2631 * Another thread could have failed, need to check if we
2632 * have reloc_root actually set.
2633 */
2634 if (!root->reloc_root) {
2635 ret = -ENOENT;
2636 goto out;
2637 }
2638 root = root->reloc_root;
2639 node->new_bytenr = root->node->start;
2640 btrfs_put_root(node->root);
2641 node->root = btrfs_grab_root(root);
2642 ASSERT(node->root);
2643 list_add_tail(&node->list, &rc->backref_cache.changed);
2644 } else {
2645 path->lowest_level = node->level;
2646 if (root == root->fs_info->chunk_root)
2647 btrfs_reserve_chunk_metadata(trans, false);
2648 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2649 btrfs_release_path(path);
2650 if (root == root->fs_info->chunk_root)
2651 btrfs_trans_release_chunk_metadata(trans);
2652 if (ret > 0)
2653 ret = 0;
2654 }
2655 if (!ret)
2656 update_processed_blocks(rc, node);
2657 } else {
2658 ret = do_relocation(trans, rc, node, key, path, 1);
2659 }
2660out:
2661 if (ret || node->level == 0 || node->cowonly)
2662 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2663 return ret;
2664}
2665
2666/*
2667 * relocate a list of blocks
2668 */
2669static noinline_for_stack
2670int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2671 struct reloc_control *rc, struct rb_root *blocks)
2672{
2673 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2674 struct btrfs_backref_node *node;
2675 struct btrfs_path *path;
2676 struct tree_block *block;
2677 struct tree_block *next;
2678 int ret = 0;
2679
2680 path = btrfs_alloc_path();
2681 if (!path) {
2682 ret = -ENOMEM;
2683 goto out_free_blocks;
2684 }
2685
2686 /* Kick in readahead for tree blocks with missing keys */
2687 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2688 if (!block->key_ready)
2689 btrfs_readahead_tree_block(fs_info, block->bytenr,
2690 block->owner, 0,
2691 block->level);
2692 }
2693
2694 /* Get first keys */
2695 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2696 if (!block->key_ready) {
2697 ret = get_tree_block_key(fs_info, block);
2698 if (ret)
2699 goto out_free_path;
2700 }
2701 }
2702
2703 /* Do tree relocation */
2704 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2705 node = build_backref_tree(trans, rc, &block->key,
2706 block->level, block->bytenr);
2707 if (IS_ERR(node)) {
2708 ret = PTR_ERR(node);
2709 goto out;
2710 }
2711
2712 ret = relocate_tree_block(trans, rc, node, &block->key,
2713 path);
2714 if (ret < 0)
2715 break;
2716 }
2717out:
2718 ret = finish_pending_nodes(trans, rc, path, ret);
2719
2720out_free_path:
2721 btrfs_free_path(path);
2722out_free_blocks:
2723 free_block_list(blocks);
2724 return ret;
2725}
2726
2727static noinline_for_stack int prealloc_file_extent_cluster(struct reloc_control *rc)
2728{
2729 const struct file_extent_cluster *cluster = &rc->cluster;
2730 struct btrfs_inode *inode = BTRFS_I(rc->data_inode);
2731 u64 alloc_hint = 0;
2732 u64 start;
2733 u64 end;
2734 u64 offset = inode->reloc_block_group_start;
2735 u64 num_bytes;
2736 int nr;
2737 int ret = 0;
2738 u64 i_size = i_size_read(&inode->vfs_inode);
2739 u64 prealloc_start = cluster->start - offset;
2740 u64 prealloc_end = cluster->end - offset;
2741 u64 cur_offset = prealloc_start;
2742
2743 /*
2744 * For subpage case, previous i_size may not be aligned to PAGE_SIZE.
2745 * This means the range [i_size, PAGE_END + 1) is filled with zeros by
2746 * btrfs_do_readpage() call of previously relocated file cluster.
2747 *
2748 * If the current cluster starts in the above range, btrfs_do_readpage()
2749 * will skip the read, and relocate_one_folio() will later writeback
2750 * the padding zeros as new data, causing data corruption.
2751 *
2752 * Here we have to manually invalidate the range (i_size, PAGE_END + 1).
2753 */
2754 if (!PAGE_ALIGNED(i_size)) {
2755 struct address_space *mapping = inode->vfs_inode.i_mapping;
2756 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2757 const u32 sectorsize = fs_info->sectorsize;
2758 struct folio *folio;
2759
2760 ASSERT(sectorsize < PAGE_SIZE);
2761 ASSERT(IS_ALIGNED(i_size, sectorsize));
2762
2763 /*
2764 * Subpage can't handle page with DIRTY but without UPTODATE
2765 * bit as it can lead to the following deadlock:
2766 *
2767 * btrfs_read_folio()
2768 * | Page already *locked*
2769 * |- btrfs_lock_and_flush_ordered_range()
2770 * |- btrfs_start_ordered_extent()
2771 * |- extent_write_cache_pages()
2772 * |- lock_page()
2773 * We try to lock the page we already hold.
2774 *
2775 * Here we just writeback the whole data reloc inode, so that
2776 * we will be ensured to have no dirty range in the page, and
2777 * are safe to clear the uptodate bits.
2778 *
2779 * This shouldn't cause too much overhead, as we need to write
2780 * the data back anyway.
2781 */
2782 ret = filemap_write_and_wait(mapping);
2783 if (ret < 0)
2784 return ret;
2785
2786 clear_extent_bits(&inode->io_tree, i_size,
2787 round_up(i_size, PAGE_SIZE) - 1,
2788 EXTENT_UPTODATE);
2789 folio = filemap_lock_folio(mapping, i_size >> PAGE_SHIFT);
2790 /*
2791 * If page is freed we don't need to do anything then, as we
2792 * will re-read the whole page anyway.
2793 */
2794 if (!IS_ERR(folio)) {
2795 btrfs_subpage_clear_uptodate(fs_info, folio, i_size,
2796 round_up(i_size, PAGE_SIZE) - i_size);
2797 folio_unlock(folio);
2798 folio_put(folio);
2799 }
2800 }
2801
2802 BUG_ON(cluster->start != cluster->boundary[0]);
2803 ret = btrfs_alloc_data_chunk_ondemand(inode,
2804 prealloc_end + 1 - prealloc_start);
2805 if (ret)
2806 return ret;
2807
2808 btrfs_inode_lock(inode, 0);
2809 for (nr = 0; nr < cluster->nr; nr++) {
2810 struct extent_state *cached_state = NULL;
2811
2812 start = cluster->boundary[nr] - offset;
2813 if (nr + 1 < cluster->nr)
2814 end = cluster->boundary[nr + 1] - 1 - offset;
2815 else
2816 end = cluster->end - offset;
2817
2818 lock_extent(&inode->io_tree, start, end, &cached_state);
2819 num_bytes = end + 1 - start;
2820 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2821 num_bytes, num_bytes,
2822 end + 1, &alloc_hint);
2823 cur_offset = end + 1;
2824 unlock_extent(&inode->io_tree, start, end, &cached_state);
2825 if (ret)
2826 break;
2827 }
2828 btrfs_inode_unlock(inode, 0);
2829
2830 if (cur_offset < prealloc_end)
2831 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2832 prealloc_end + 1 - cur_offset);
2833 return ret;
2834}
2835
2836static noinline_for_stack int setup_relocation_extent_mapping(struct reloc_control *rc)
2837{
2838 struct btrfs_inode *inode = BTRFS_I(rc->data_inode);
2839 struct extent_map *em;
2840 struct extent_state *cached_state = NULL;
2841 u64 offset = inode->reloc_block_group_start;
2842 u64 start = rc->cluster.start - offset;
2843 u64 end = rc->cluster.end - offset;
2844 int ret = 0;
2845
2846 em = alloc_extent_map();
2847 if (!em)
2848 return -ENOMEM;
2849
2850 em->start = start;
2851 em->len = end + 1 - start;
2852 em->disk_bytenr = rc->cluster.start;
2853 em->disk_num_bytes = em->len;
2854 em->ram_bytes = em->len;
2855 em->flags |= EXTENT_FLAG_PINNED;
2856
2857 lock_extent(&inode->io_tree, start, end, &cached_state);
2858 ret = btrfs_replace_extent_map_range(inode, em, false);
2859 unlock_extent(&inode->io_tree, start, end, &cached_state);
2860 free_extent_map(em);
2861
2862 return ret;
2863}
2864
2865/*
2866 * Allow error injection to test balance/relocation cancellation
2867 */
2868noinline int btrfs_should_cancel_balance(const struct btrfs_fs_info *fs_info)
2869{
2870 return atomic_read(&fs_info->balance_cancel_req) ||
2871 atomic_read(&fs_info->reloc_cancel_req) ||
2872 fatal_signal_pending(current);
2873}
2874ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2875
2876static u64 get_cluster_boundary_end(const struct file_extent_cluster *cluster,
2877 int cluster_nr)
2878{
2879 /* Last extent, use cluster end directly */
2880 if (cluster_nr >= cluster->nr - 1)
2881 return cluster->end;
2882
2883 /* Use next boundary start*/
2884 return cluster->boundary[cluster_nr + 1] - 1;
2885}
2886
2887static int relocate_one_folio(struct reloc_control *rc,
2888 struct file_ra_state *ra,
2889 int *cluster_nr, unsigned long index)
2890{
2891 const struct file_extent_cluster *cluster = &rc->cluster;
2892 struct inode *inode = rc->data_inode;
2893 struct btrfs_fs_info *fs_info = inode_to_fs_info(inode);
2894 u64 offset = BTRFS_I(inode)->reloc_block_group_start;
2895 const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT;
2896 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2897 struct folio *folio;
2898 u64 folio_start;
2899 u64 folio_end;
2900 u64 cur;
2901 int ret;
2902 const bool use_rst = btrfs_need_stripe_tree_update(fs_info, rc->block_group->flags);
2903
2904 ASSERT(index <= last_index);
2905again:
2906 folio = filemap_lock_folio(inode->i_mapping, index);
2907 if (IS_ERR(folio)) {
2908
2909 /*
2910 * On relocation we're doing readahead on the relocation inode,
2911 * but if the filesystem is backed by a RAID stripe tree we can
2912 * get ENOENT (e.g. due to preallocated extents not being
2913 * mapped in the RST) from the lookup.
2914 *
2915 * But readahead doesn't handle the error and submits invalid
2916 * reads to the device, causing a assertion failures.
2917 */
2918 if (!use_rst)
2919 page_cache_sync_readahead(inode->i_mapping, ra, NULL,
2920 index, last_index + 1 - index);
2921 folio = __filemap_get_folio(inode->i_mapping, index,
2922 FGP_LOCK | FGP_ACCESSED | FGP_CREAT,
2923 mask);
2924 if (IS_ERR(folio))
2925 return PTR_ERR(folio);
2926 }
2927
2928 WARN_ON(folio_order(folio));
2929
2930 if (folio_test_readahead(folio) && !use_rst)
2931 page_cache_async_readahead(inode->i_mapping, ra, NULL,
2932 folio, last_index + 1 - index);
2933
2934 if (!folio_test_uptodate(folio)) {
2935 btrfs_read_folio(NULL, folio);
2936 folio_lock(folio);
2937 if (!folio_test_uptodate(folio)) {
2938 ret = -EIO;
2939 goto release_folio;
2940 }
2941 if (folio->mapping != inode->i_mapping) {
2942 folio_unlock(folio);
2943 folio_put(folio);
2944 goto again;
2945 }
2946 }
2947
2948 /*
2949 * We could have lost folio private when we dropped the lock to read the
2950 * folio above, make sure we set_page_extent_mapped here so we have any
2951 * of the subpage blocksize stuff we need in place.
2952 */
2953 ret = set_folio_extent_mapped(folio);
2954 if (ret < 0)
2955 goto release_folio;
2956
2957 folio_start = folio_pos(folio);
2958 folio_end = folio_start + PAGE_SIZE - 1;
2959
2960 /*
2961 * Start from the cluster, as for subpage case, the cluster can start
2962 * inside the folio.
2963 */
2964 cur = max(folio_start, cluster->boundary[*cluster_nr] - offset);
2965 while (cur <= folio_end) {
2966 struct extent_state *cached_state = NULL;
2967 u64 extent_start = cluster->boundary[*cluster_nr] - offset;
2968 u64 extent_end = get_cluster_boundary_end(cluster,
2969 *cluster_nr) - offset;
2970 u64 clamped_start = max(folio_start, extent_start);
2971 u64 clamped_end = min(folio_end, extent_end);
2972 u32 clamped_len = clamped_end + 1 - clamped_start;
2973
2974 /* Reserve metadata for this range */
2975 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
2976 clamped_len, clamped_len,
2977 false);
2978 if (ret)
2979 goto release_folio;
2980
2981 /* Mark the range delalloc and dirty for later writeback */
2982 lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
2983 &cached_state);
2984 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start,
2985 clamped_end, 0, &cached_state);
2986 if (ret) {
2987 clear_extent_bit(&BTRFS_I(inode)->io_tree,
2988 clamped_start, clamped_end,
2989 EXTENT_LOCKED | EXTENT_BOUNDARY,
2990 &cached_state);
2991 btrfs_delalloc_release_metadata(BTRFS_I(inode),
2992 clamped_len, true);
2993 btrfs_delalloc_release_extents(BTRFS_I(inode),
2994 clamped_len);
2995 goto release_folio;
2996 }
2997 btrfs_folio_set_dirty(fs_info, folio, clamped_start, clamped_len);
2998
2999 /*
3000 * Set the boundary if it's inside the folio.
3001 * Data relocation requires the destination extents to have the
3002 * same size as the source.
3003 * EXTENT_BOUNDARY bit prevents current extent from being merged
3004 * with previous extent.
3005 */
3006 if (in_range(cluster->boundary[*cluster_nr] - offset, folio_start, PAGE_SIZE)) {
3007 u64 boundary_start = cluster->boundary[*cluster_nr] -
3008 offset;
3009 u64 boundary_end = boundary_start +
3010 fs_info->sectorsize - 1;
3011
3012 set_extent_bit(&BTRFS_I(inode)->io_tree,
3013 boundary_start, boundary_end,
3014 EXTENT_BOUNDARY, NULL);
3015 }
3016 unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3017 &cached_state);
3018 btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len);
3019 cur += clamped_len;
3020
3021 /* Crossed extent end, go to next extent */
3022 if (cur >= extent_end) {
3023 (*cluster_nr)++;
3024 /* Just finished the last extent of the cluster, exit. */
3025 if (*cluster_nr >= cluster->nr)
3026 break;
3027 }
3028 }
3029 folio_unlock(folio);
3030 folio_put(folio);
3031
3032 balance_dirty_pages_ratelimited(inode->i_mapping);
3033 btrfs_throttle(fs_info);
3034 if (btrfs_should_cancel_balance(fs_info))
3035 ret = -ECANCELED;
3036 return ret;
3037
3038release_folio:
3039 folio_unlock(folio);
3040 folio_put(folio);
3041 return ret;
3042}
3043
3044static int relocate_file_extent_cluster(struct reloc_control *rc)
3045{
3046 struct inode *inode = rc->data_inode;
3047 const struct file_extent_cluster *cluster = &rc->cluster;
3048 u64 offset = BTRFS_I(inode)->reloc_block_group_start;
3049 unsigned long index;
3050 unsigned long last_index;
3051 struct file_ra_state *ra;
3052 int cluster_nr = 0;
3053 int ret = 0;
3054
3055 if (!cluster->nr)
3056 return 0;
3057
3058 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3059 if (!ra)
3060 return -ENOMEM;
3061
3062 ret = prealloc_file_extent_cluster(rc);
3063 if (ret)
3064 goto out;
3065
3066 file_ra_state_init(ra, inode->i_mapping);
3067
3068 ret = setup_relocation_extent_mapping(rc);
3069 if (ret)
3070 goto out;
3071
3072 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3073 for (index = (cluster->start - offset) >> PAGE_SHIFT;
3074 index <= last_index && !ret; index++)
3075 ret = relocate_one_folio(rc, ra, &cluster_nr, index);
3076 if (ret == 0)
3077 WARN_ON(cluster_nr != cluster->nr);
3078out:
3079 kfree(ra);
3080 return ret;
3081}
3082
3083static noinline_for_stack int relocate_data_extent(struct reloc_control *rc,
3084 const struct btrfs_key *extent_key)
3085{
3086 struct inode *inode = rc->data_inode;
3087 struct file_extent_cluster *cluster = &rc->cluster;
3088 int ret;
3089 struct btrfs_root *root = BTRFS_I(inode)->root;
3090
3091 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3092 ret = relocate_file_extent_cluster(rc);
3093 if (ret)
3094 return ret;
3095 cluster->nr = 0;
3096 }
3097
3098 /*
3099 * Under simple quotas, we set root->relocation_src_root when we find
3100 * the extent. If adjacent extents have different owners, we can't merge
3101 * them while relocating. Handle this by storing the owning root that
3102 * started a cluster and if we see an extent from a different root break
3103 * cluster formation (just like the above case of non-adjacent extents).
3104 *
3105 * Without simple quotas, relocation_src_root is always 0, so we should
3106 * never see a mismatch, and it should have no effect on relocation
3107 * clusters.
3108 */
3109 if (cluster->nr > 0 && cluster->owning_root != root->relocation_src_root) {
3110 u64 tmp = root->relocation_src_root;
3111
3112 /*
3113 * root->relocation_src_root is the state that actually affects
3114 * the preallocation we do here, so set it to the root owning
3115 * the cluster we need to relocate.
3116 */
3117 root->relocation_src_root = cluster->owning_root;
3118 ret = relocate_file_extent_cluster(rc);
3119 if (ret)
3120 return ret;
3121 cluster->nr = 0;
3122 /* And reset it back for the current extent's owning root. */
3123 root->relocation_src_root = tmp;
3124 }
3125
3126 if (!cluster->nr) {
3127 cluster->start = extent_key->objectid;
3128 cluster->owning_root = root->relocation_src_root;
3129 }
3130 else
3131 BUG_ON(cluster->nr >= MAX_EXTENTS);
3132 cluster->end = extent_key->objectid + extent_key->offset - 1;
3133 cluster->boundary[cluster->nr] = extent_key->objectid;
3134 cluster->nr++;
3135
3136 if (cluster->nr >= MAX_EXTENTS) {
3137 ret = relocate_file_extent_cluster(rc);
3138 if (ret)
3139 return ret;
3140 cluster->nr = 0;
3141 }
3142 return 0;
3143}
3144
3145/*
3146 * helper to add a tree block to the list.
3147 * the major work is getting the generation and level of the block
3148 */
3149static int add_tree_block(struct reloc_control *rc,
3150 const struct btrfs_key *extent_key,
3151 struct btrfs_path *path,
3152 struct rb_root *blocks)
3153{
3154 struct extent_buffer *eb;
3155 struct btrfs_extent_item *ei;
3156 struct btrfs_tree_block_info *bi;
3157 struct tree_block *block;
3158 struct rb_node *rb_node;
3159 u32 item_size;
3160 int level = -1;
3161 u64 generation;
3162 u64 owner = 0;
3163
3164 eb = path->nodes[0];
3165 item_size = btrfs_item_size(eb, path->slots[0]);
3166
3167 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3168 item_size >= sizeof(*ei) + sizeof(*bi)) {
3169 unsigned long ptr = 0, end;
3170
3171 ei = btrfs_item_ptr(eb, path->slots[0],
3172 struct btrfs_extent_item);
3173 end = (unsigned long)ei + item_size;
3174 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3175 bi = (struct btrfs_tree_block_info *)(ei + 1);
3176 level = btrfs_tree_block_level(eb, bi);
3177 ptr = (unsigned long)(bi + 1);
3178 } else {
3179 level = (int)extent_key->offset;
3180 ptr = (unsigned long)(ei + 1);
3181 }
3182 generation = btrfs_extent_generation(eb, ei);
3183
3184 /*
3185 * We're reading random blocks without knowing their owner ahead
3186 * of time. This is ok most of the time, as all reloc roots and
3187 * fs roots have the same lock type. However normal trees do
3188 * not, and the only way to know ahead of time is to read the
3189 * inline ref offset. We know it's an fs root if
3190 *
3191 * 1. There's more than one ref.
3192 * 2. There's a SHARED_DATA_REF_KEY set.
3193 * 3. FULL_BACKREF is set on the flags.
3194 *
3195 * Otherwise it's safe to assume that the ref offset == the
3196 * owner of this block, so we can use that when calling
3197 * read_tree_block.
3198 */
3199 if (btrfs_extent_refs(eb, ei) == 1 &&
3200 !(btrfs_extent_flags(eb, ei) &
3201 BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
3202 ptr < end) {
3203 struct btrfs_extent_inline_ref *iref;
3204 int type;
3205
3206 iref = (struct btrfs_extent_inline_ref *)ptr;
3207 type = btrfs_get_extent_inline_ref_type(eb, iref,
3208 BTRFS_REF_TYPE_BLOCK);
3209 if (type == BTRFS_REF_TYPE_INVALID)
3210 return -EINVAL;
3211 if (type == BTRFS_TREE_BLOCK_REF_KEY)
3212 owner = btrfs_extent_inline_ref_offset(eb, iref);
3213 }
3214 } else {
3215 btrfs_print_leaf(eb);
3216 btrfs_err(rc->block_group->fs_info,
3217 "unrecognized tree backref at tree block %llu slot %u",
3218 eb->start, path->slots[0]);
3219 btrfs_release_path(path);
3220 return -EUCLEAN;
3221 }
3222
3223 btrfs_release_path(path);
3224
3225 BUG_ON(level == -1);
3226
3227 block = kmalloc(sizeof(*block), GFP_NOFS);
3228 if (!block)
3229 return -ENOMEM;
3230
3231 block->bytenr = extent_key->objectid;
3232 block->key.objectid = rc->extent_root->fs_info->nodesize;
3233 block->key.offset = generation;
3234 block->level = level;
3235 block->key_ready = false;
3236 block->owner = owner;
3237
3238 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
3239 if (rb_node)
3240 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
3241 -EEXIST);
3242
3243 return 0;
3244}
3245
3246/*
3247 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3248 */
3249static int __add_tree_block(struct reloc_control *rc,
3250 u64 bytenr, u32 blocksize,
3251 struct rb_root *blocks)
3252{
3253 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3254 struct btrfs_path *path;
3255 struct btrfs_key key;
3256 int ret;
3257 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3258
3259 if (tree_block_processed(bytenr, rc))
3260 return 0;
3261
3262 if (rb_simple_search(blocks, bytenr))
3263 return 0;
3264
3265 path = btrfs_alloc_path();
3266 if (!path)
3267 return -ENOMEM;
3268again:
3269 key.objectid = bytenr;
3270 if (skinny) {
3271 key.type = BTRFS_METADATA_ITEM_KEY;
3272 key.offset = (u64)-1;
3273 } else {
3274 key.type = BTRFS_EXTENT_ITEM_KEY;
3275 key.offset = blocksize;
3276 }
3277
3278 path->search_commit_root = 1;
3279 path->skip_locking = 1;
3280 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3281 if (ret < 0)
3282 goto out;
3283
3284 if (ret > 0 && skinny) {
3285 if (path->slots[0]) {
3286 path->slots[0]--;
3287 btrfs_item_key_to_cpu(path->nodes[0], &key,
3288 path->slots[0]);
3289 if (key.objectid == bytenr &&
3290 (key.type == BTRFS_METADATA_ITEM_KEY ||
3291 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3292 key.offset == blocksize)))
3293 ret = 0;
3294 }
3295
3296 if (ret) {
3297 skinny = false;
3298 btrfs_release_path(path);
3299 goto again;
3300 }
3301 }
3302 if (ret) {
3303 ASSERT(ret == 1);
3304 btrfs_print_leaf(path->nodes[0]);
3305 btrfs_err(fs_info,
3306 "tree block extent item (%llu) is not found in extent tree",
3307 bytenr);
3308 WARN_ON(1);
3309 ret = -EINVAL;
3310 goto out;
3311 }
3312
3313 ret = add_tree_block(rc, &key, path, blocks);
3314out:
3315 btrfs_free_path(path);
3316 return ret;
3317}
3318
3319static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3320 struct btrfs_block_group *block_group,
3321 struct inode *inode,
3322 u64 ino)
3323{
3324 struct btrfs_root *root = fs_info->tree_root;
3325 struct btrfs_trans_handle *trans;
3326 int ret = 0;
3327
3328 if (inode)
3329 goto truncate;
3330
3331 inode = btrfs_iget(ino, root);
3332 if (IS_ERR(inode))
3333 return -ENOENT;
3334
3335truncate:
3336 ret = btrfs_check_trunc_cache_free_space(fs_info,
3337 &fs_info->global_block_rsv);
3338 if (ret)
3339 goto out;
3340
3341 trans = btrfs_join_transaction(root);
3342 if (IS_ERR(trans)) {
3343 ret = PTR_ERR(trans);
3344 goto out;
3345 }
3346
3347 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3348
3349 btrfs_end_transaction(trans);
3350 btrfs_btree_balance_dirty(fs_info);
3351out:
3352 iput(inode);
3353 return ret;
3354}
3355
3356/*
3357 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3358 * cache inode, to avoid free space cache data extent blocking data relocation.
3359 */
3360static int delete_v1_space_cache(struct extent_buffer *leaf,
3361 struct btrfs_block_group *block_group,
3362 u64 data_bytenr)
3363{
3364 u64 space_cache_ino;
3365 struct btrfs_file_extent_item *ei;
3366 struct btrfs_key key;
3367 bool found = false;
3368 int i;
3369 int ret;
3370
3371 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3372 return 0;
3373
3374 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3375 u8 type;
3376
3377 btrfs_item_key_to_cpu(leaf, &key, i);
3378 if (key.type != BTRFS_EXTENT_DATA_KEY)
3379 continue;
3380 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3381 type = btrfs_file_extent_type(leaf, ei);
3382
3383 if ((type == BTRFS_FILE_EXTENT_REG ||
3384 type == BTRFS_FILE_EXTENT_PREALLOC) &&
3385 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3386 found = true;
3387 space_cache_ino = key.objectid;
3388 break;
3389 }
3390 }
3391 if (!found)
3392 return -ENOENT;
3393 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3394 space_cache_ino);
3395 return ret;
3396}
3397
3398/*
3399 * helper to find all tree blocks that reference a given data extent
3400 */
3401static noinline_for_stack int add_data_references(struct reloc_control *rc,
3402 const struct btrfs_key *extent_key,
3403 struct btrfs_path *path,
3404 struct rb_root *blocks)
3405{
3406 struct btrfs_backref_walk_ctx ctx = { 0 };
3407 struct ulist_iterator leaf_uiter;
3408 struct ulist_node *ref_node = NULL;
3409 const u32 blocksize = rc->extent_root->fs_info->nodesize;
3410 int ret = 0;
3411
3412 btrfs_release_path(path);
3413
3414 ctx.bytenr = extent_key->objectid;
3415 ctx.skip_inode_ref_list = true;
3416 ctx.fs_info = rc->extent_root->fs_info;
3417
3418 ret = btrfs_find_all_leafs(&ctx);
3419 if (ret < 0)
3420 return ret;
3421
3422 ULIST_ITER_INIT(&leaf_uiter);
3423 while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
3424 struct btrfs_tree_parent_check check = { 0 };
3425 struct extent_buffer *eb;
3426
3427 eb = read_tree_block(ctx.fs_info, ref_node->val, &check);
3428 if (IS_ERR(eb)) {
3429 ret = PTR_ERR(eb);
3430 break;
3431 }
3432 ret = delete_v1_space_cache(eb, rc->block_group,
3433 extent_key->objectid);
3434 free_extent_buffer(eb);
3435 if (ret < 0)
3436 break;
3437 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3438 if (ret < 0)
3439 break;
3440 }
3441 if (ret < 0)
3442 free_block_list(blocks);
3443 ulist_free(ctx.refs);
3444 return ret;
3445}
3446
3447/*
3448 * helper to find next unprocessed extent
3449 */
3450static noinline_for_stack
3451int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3452 struct btrfs_key *extent_key)
3453{
3454 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3455 struct btrfs_key key;
3456 struct extent_buffer *leaf;
3457 u64 start, end, last;
3458 int ret;
3459
3460 last = rc->block_group->start + rc->block_group->length;
3461 while (1) {
3462 bool block_found;
3463
3464 cond_resched();
3465 if (rc->search_start >= last) {
3466 ret = 1;
3467 break;
3468 }
3469
3470 key.objectid = rc->search_start;
3471 key.type = BTRFS_EXTENT_ITEM_KEY;
3472 key.offset = 0;
3473
3474 path->search_commit_root = 1;
3475 path->skip_locking = 1;
3476 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3477 0, 0);
3478 if (ret < 0)
3479 break;
3480next:
3481 leaf = path->nodes[0];
3482 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3483 ret = btrfs_next_leaf(rc->extent_root, path);
3484 if (ret != 0)
3485 break;
3486 leaf = path->nodes[0];
3487 }
3488
3489 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3490 if (key.objectid >= last) {
3491 ret = 1;
3492 break;
3493 }
3494
3495 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3496 key.type != BTRFS_METADATA_ITEM_KEY) {
3497 path->slots[0]++;
3498 goto next;
3499 }
3500
3501 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3502 key.objectid + key.offset <= rc->search_start) {
3503 path->slots[0]++;
3504 goto next;
3505 }
3506
3507 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3508 key.objectid + fs_info->nodesize <=
3509 rc->search_start) {
3510 path->slots[0]++;
3511 goto next;
3512 }
3513
3514 block_found = find_first_extent_bit(&rc->processed_blocks,
3515 key.objectid, &start, &end,
3516 EXTENT_DIRTY, NULL);
3517
3518 if (block_found && start <= key.objectid) {
3519 btrfs_release_path(path);
3520 rc->search_start = end + 1;
3521 } else {
3522 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3523 rc->search_start = key.objectid + key.offset;
3524 else
3525 rc->search_start = key.objectid +
3526 fs_info->nodesize;
3527 memcpy(extent_key, &key, sizeof(key));
3528 return 0;
3529 }
3530 }
3531 btrfs_release_path(path);
3532 return ret;
3533}
3534
3535static void set_reloc_control(struct reloc_control *rc)
3536{
3537 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3538
3539 mutex_lock(&fs_info->reloc_mutex);
3540 fs_info->reloc_ctl = rc;
3541 mutex_unlock(&fs_info->reloc_mutex);
3542}
3543
3544static void unset_reloc_control(struct reloc_control *rc)
3545{
3546 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3547
3548 mutex_lock(&fs_info->reloc_mutex);
3549 fs_info->reloc_ctl = NULL;
3550 mutex_unlock(&fs_info->reloc_mutex);
3551}
3552
3553static noinline_for_stack
3554int prepare_to_relocate(struct reloc_control *rc)
3555{
3556 struct btrfs_trans_handle *trans;
3557 int ret;
3558
3559 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3560 BTRFS_BLOCK_RSV_TEMP);
3561 if (!rc->block_rsv)
3562 return -ENOMEM;
3563
3564 memset(&rc->cluster, 0, sizeof(rc->cluster));
3565 rc->search_start = rc->block_group->start;
3566 rc->extents_found = 0;
3567 rc->nodes_relocated = 0;
3568 rc->merging_rsv_size = 0;
3569 rc->reserved_bytes = 0;
3570 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3571 RELOCATION_RESERVED_NODES;
3572 ret = btrfs_block_rsv_refill(rc->extent_root->fs_info,
3573 rc->block_rsv, rc->block_rsv->size,
3574 BTRFS_RESERVE_FLUSH_ALL);
3575 if (ret)
3576 return ret;
3577
3578 rc->create_reloc_tree = true;
3579 set_reloc_control(rc);
3580
3581 trans = btrfs_join_transaction(rc->extent_root);
3582 if (IS_ERR(trans)) {
3583 unset_reloc_control(rc);
3584 /*
3585 * extent tree is not a ref_cow tree and has no reloc_root to
3586 * cleanup. And callers are responsible to free the above
3587 * block rsv.
3588 */
3589 return PTR_ERR(trans);
3590 }
3591
3592 ret = btrfs_commit_transaction(trans);
3593 if (ret)
3594 unset_reloc_control(rc);
3595
3596 return ret;
3597}
3598
3599static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3600{
3601 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3602 struct rb_root blocks = RB_ROOT;
3603 struct btrfs_key key;
3604 struct btrfs_trans_handle *trans = NULL;
3605 struct btrfs_path *path;
3606 struct btrfs_extent_item *ei;
3607 u64 flags;
3608 int ret;
3609 int err = 0;
3610 int progress = 0;
3611
3612 path = btrfs_alloc_path();
3613 if (!path)
3614 return -ENOMEM;
3615 path->reada = READA_FORWARD;
3616
3617 ret = prepare_to_relocate(rc);
3618 if (ret) {
3619 err = ret;
3620 goto out_free;
3621 }
3622
3623 while (1) {
3624 rc->reserved_bytes = 0;
3625 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
3626 rc->block_rsv->size,
3627 BTRFS_RESERVE_FLUSH_ALL);
3628 if (ret) {
3629 err = ret;
3630 break;
3631 }
3632 progress++;
3633 trans = btrfs_start_transaction(rc->extent_root, 0);
3634 if (IS_ERR(trans)) {
3635 err = PTR_ERR(trans);
3636 trans = NULL;
3637 break;
3638 }
3639restart:
3640 if (rc->backref_cache.last_trans != trans->transid)
3641 btrfs_backref_release_cache(&rc->backref_cache);
3642 rc->backref_cache.last_trans = trans->transid;
3643
3644 ret = find_next_extent(rc, path, &key);
3645 if (ret < 0)
3646 err = ret;
3647 if (ret != 0)
3648 break;
3649
3650 rc->extents_found++;
3651
3652 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3653 struct btrfs_extent_item);
3654 flags = btrfs_extent_flags(path->nodes[0], ei);
3655
3656 /*
3657 * If we are relocating a simple quota owned extent item, we
3658 * need to note the owner on the reloc data root so that when
3659 * we allocate the replacement item, we can attribute it to the
3660 * correct eventual owner (rather than the reloc data root).
3661 */
3662 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) {
3663 struct btrfs_root *root = BTRFS_I(rc->data_inode)->root;
3664 u64 owning_root_id = btrfs_get_extent_owner_root(fs_info,
3665 path->nodes[0],
3666 path->slots[0]);
3667
3668 root->relocation_src_root = owning_root_id;
3669 }
3670
3671 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3672 ret = add_tree_block(rc, &key, path, &blocks);
3673 } else if (rc->stage == UPDATE_DATA_PTRS &&
3674 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3675 ret = add_data_references(rc, &key, path, &blocks);
3676 } else {
3677 btrfs_release_path(path);
3678 ret = 0;
3679 }
3680 if (ret < 0) {
3681 err = ret;
3682 break;
3683 }
3684
3685 if (!RB_EMPTY_ROOT(&blocks)) {
3686 ret = relocate_tree_blocks(trans, rc, &blocks);
3687 if (ret < 0) {
3688 if (ret != -EAGAIN) {
3689 err = ret;
3690 break;
3691 }
3692 rc->extents_found--;
3693 rc->search_start = key.objectid;
3694 }
3695 }
3696
3697 btrfs_end_transaction_throttle(trans);
3698 btrfs_btree_balance_dirty(fs_info);
3699 trans = NULL;
3700
3701 if (rc->stage == MOVE_DATA_EXTENTS &&
3702 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3703 rc->found_file_extent = true;
3704 ret = relocate_data_extent(rc, &key);
3705 if (ret < 0) {
3706 err = ret;
3707 break;
3708 }
3709 }
3710 if (btrfs_should_cancel_balance(fs_info)) {
3711 err = -ECANCELED;
3712 break;
3713 }
3714 }
3715 if (trans && progress && err == -ENOSPC) {
3716 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3717 if (ret == 1) {
3718 err = 0;
3719 progress = 0;
3720 goto restart;
3721 }
3722 }
3723
3724 btrfs_release_path(path);
3725 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3726
3727 if (trans) {
3728 btrfs_end_transaction_throttle(trans);
3729 btrfs_btree_balance_dirty(fs_info);
3730 }
3731
3732 if (!err) {
3733 ret = relocate_file_extent_cluster(rc);
3734 if (ret < 0)
3735 err = ret;
3736 }
3737
3738 rc->create_reloc_tree = false;
3739 set_reloc_control(rc);
3740
3741 btrfs_backref_release_cache(&rc->backref_cache);
3742 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3743
3744 /*
3745 * Even in the case when the relocation is cancelled, we should all go
3746 * through prepare_to_merge() and merge_reloc_roots().
3747 *
3748 * For error (including cancelled balance), prepare_to_merge() will
3749 * mark all reloc trees orphan, then queue them for cleanup in
3750 * merge_reloc_roots()
3751 */
3752 err = prepare_to_merge(rc, err);
3753
3754 merge_reloc_roots(rc);
3755
3756 rc->merge_reloc_tree = false;
3757 unset_reloc_control(rc);
3758 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3759
3760 /* get rid of pinned extents */
3761 trans = btrfs_join_transaction(rc->extent_root);
3762 if (IS_ERR(trans)) {
3763 err = PTR_ERR(trans);
3764 goto out_free;
3765 }
3766 ret = btrfs_commit_transaction(trans);
3767 if (ret && !err)
3768 err = ret;
3769out_free:
3770 ret = clean_dirty_subvols(rc);
3771 if (ret < 0 && !err)
3772 err = ret;
3773 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3774 btrfs_free_path(path);
3775 return err;
3776}
3777
3778static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3779 struct btrfs_root *root, u64 objectid)
3780{
3781 struct btrfs_path *path;
3782 struct btrfs_inode_item *item;
3783 struct extent_buffer *leaf;
3784 int ret;
3785
3786 path = btrfs_alloc_path();
3787 if (!path)
3788 return -ENOMEM;
3789
3790 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3791 if (ret)
3792 goto out;
3793
3794 leaf = path->nodes[0];
3795 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3796 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3797 btrfs_set_inode_generation(leaf, item, 1);
3798 btrfs_set_inode_size(leaf, item, 0);
3799 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3800 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3801 BTRFS_INODE_PREALLOC);
3802 btrfs_mark_buffer_dirty(trans, leaf);
3803out:
3804 btrfs_free_path(path);
3805 return ret;
3806}
3807
3808static void delete_orphan_inode(struct btrfs_trans_handle *trans,
3809 struct btrfs_root *root, u64 objectid)
3810{
3811 struct btrfs_path *path;
3812 struct btrfs_key key;
3813 int ret = 0;
3814
3815 path = btrfs_alloc_path();
3816 if (!path) {
3817 ret = -ENOMEM;
3818 goto out;
3819 }
3820
3821 key.objectid = objectid;
3822 key.type = BTRFS_INODE_ITEM_KEY;
3823 key.offset = 0;
3824 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3825 if (ret) {
3826 if (ret > 0)
3827 ret = -ENOENT;
3828 goto out;
3829 }
3830 ret = btrfs_del_item(trans, root, path);
3831out:
3832 if (ret)
3833 btrfs_abort_transaction(trans, ret);
3834 btrfs_free_path(path);
3835}
3836
3837/*
3838 * helper to create inode for data relocation.
3839 * the inode is in data relocation tree and its link count is 0
3840 */
3841static noinline_for_stack struct inode *create_reloc_inode(
3842 struct btrfs_fs_info *fs_info,
3843 const struct btrfs_block_group *group)
3844{
3845 struct inode *inode = NULL;
3846 struct btrfs_trans_handle *trans;
3847 struct btrfs_root *root;
3848 u64 objectid;
3849 int ret = 0;
3850
3851 root = btrfs_grab_root(fs_info->data_reloc_root);
3852 trans = btrfs_start_transaction(root, 6);
3853 if (IS_ERR(trans)) {
3854 btrfs_put_root(root);
3855 return ERR_CAST(trans);
3856 }
3857
3858 ret = btrfs_get_free_objectid(root, &objectid);
3859 if (ret)
3860 goto out;
3861
3862 ret = __insert_orphan_inode(trans, root, objectid);
3863 if (ret)
3864 goto out;
3865
3866 inode = btrfs_iget(objectid, root);
3867 if (IS_ERR(inode)) {
3868 delete_orphan_inode(trans, root, objectid);
3869 ret = PTR_ERR(inode);
3870 inode = NULL;
3871 goto out;
3872 }
3873 BTRFS_I(inode)->reloc_block_group_start = group->start;
3874
3875 ret = btrfs_orphan_add(trans, BTRFS_I(inode));
3876out:
3877 btrfs_put_root(root);
3878 btrfs_end_transaction(trans);
3879 btrfs_btree_balance_dirty(fs_info);
3880 if (ret) {
3881 iput(inode);
3882 inode = ERR_PTR(ret);
3883 }
3884 return inode;
3885}
3886
3887/*
3888 * Mark start of chunk relocation that is cancellable. Check if the cancellation
3889 * has been requested meanwhile and don't start in that case.
3890 *
3891 * Return:
3892 * 0 success
3893 * -EINPROGRESS operation is already in progress, that's probably a bug
3894 * -ECANCELED cancellation request was set before the operation started
3895 */
3896static int reloc_chunk_start(struct btrfs_fs_info *fs_info)
3897{
3898 if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) {
3899 /* This should not happen */
3900 btrfs_err(fs_info, "reloc already running, cannot start");
3901 return -EINPROGRESS;
3902 }
3903
3904 if (atomic_read(&fs_info->reloc_cancel_req) > 0) {
3905 btrfs_info(fs_info, "chunk relocation canceled on start");
3906 /*
3907 * On cancel, clear all requests but let the caller mark
3908 * the end after cleanup operations.
3909 */
3910 atomic_set(&fs_info->reloc_cancel_req, 0);
3911 return -ECANCELED;
3912 }
3913 return 0;
3914}
3915
3916/*
3917 * Mark end of chunk relocation that is cancellable and wake any waiters.
3918 */
3919static void reloc_chunk_end(struct btrfs_fs_info *fs_info)
3920{
3921 /* Requested after start, clear bit first so any waiters can continue */
3922 if (atomic_read(&fs_info->reloc_cancel_req) > 0)
3923 btrfs_info(fs_info, "chunk relocation canceled during operation");
3924 clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags);
3925 atomic_set(&fs_info->reloc_cancel_req, 0);
3926}
3927
3928static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
3929{
3930 struct reloc_control *rc;
3931
3932 rc = kzalloc(sizeof(*rc), GFP_NOFS);
3933 if (!rc)
3934 return NULL;
3935
3936 INIT_LIST_HEAD(&rc->reloc_roots);
3937 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
3938 btrfs_backref_init_cache(fs_info, &rc->backref_cache, true);
3939 rc->reloc_root_tree.rb_root = RB_ROOT;
3940 spin_lock_init(&rc->reloc_root_tree.lock);
3941 extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS);
3942 return rc;
3943}
3944
3945static void free_reloc_control(struct reloc_control *rc)
3946{
3947 struct mapping_node *node, *tmp;
3948
3949 free_reloc_roots(&rc->reloc_roots);
3950 rbtree_postorder_for_each_entry_safe(node, tmp,
3951 &rc->reloc_root_tree.rb_root, rb_node)
3952 kfree(node);
3953
3954 kfree(rc);
3955}
3956
3957/*
3958 * Print the block group being relocated
3959 */
3960static void describe_relocation(struct btrfs_block_group *block_group)
3961{
3962 char buf[128] = {'\0'};
3963
3964 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
3965
3966 btrfs_info(block_group->fs_info, "relocating block group %llu flags %s",
3967 block_group->start, buf);
3968}
3969
3970static const char *stage_to_string(enum reloc_stage stage)
3971{
3972 if (stage == MOVE_DATA_EXTENTS)
3973 return "move data extents";
3974 if (stage == UPDATE_DATA_PTRS)
3975 return "update data pointers";
3976 return "unknown";
3977}
3978
3979/*
3980 * function to relocate all extents in a block group.
3981 */
3982int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
3983{
3984 struct btrfs_block_group *bg;
3985 struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start);
3986 struct reloc_control *rc;
3987 struct inode *inode;
3988 struct btrfs_path *path;
3989 int ret;
3990 int rw = 0;
3991 int err = 0;
3992
3993 /*
3994 * This only gets set if we had a half-deleted snapshot on mount. We
3995 * cannot allow relocation to start while we're still trying to clean up
3996 * these pending deletions.
3997 */
3998 ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
3999 if (ret)
4000 return ret;
4001
4002 /* We may have been woken up by close_ctree, so bail if we're closing. */
4003 if (btrfs_fs_closing(fs_info))
4004 return -EINTR;
4005
4006 bg = btrfs_lookup_block_group(fs_info, group_start);
4007 if (!bg)
4008 return -ENOENT;
4009
4010 /*
4011 * Relocation of a data block group creates ordered extents. Without
4012 * sb_start_write(), we can freeze the filesystem while unfinished
4013 * ordered extents are left. Such ordered extents can cause a deadlock
4014 * e.g. when syncfs() is waiting for their completion but they can't
4015 * finish because they block when joining a transaction, due to the
4016 * fact that the freeze locks are being held in write mode.
4017 */
4018 if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
4019 ASSERT(sb_write_started(fs_info->sb));
4020
4021 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4022 btrfs_put_block_group(bg);
4023 return -ETXTBSY;
4024 }
4025
4026 rc = alloc_reloc_control(fs_info);
4027 if (!rc) {
4028 btrfs_put_block_group(bg);
4029 return -ENOMEM;
4030 }
4031
4032 ret = reloc_chunk_start(fs_info);
4033 if (ret < 0) {
4034 err = ret;
4035 goto out_put_bg;
4036 }
4037
4038 rc->extent_root = extent_root;
4039 rc->block_group = bg;
4040
4041 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4042 if (ret) {
4043 err = ret;
4044 goto out;
4045 }
4046 rw = 1;
4047
4048 path = btrfs_alloc_path();
4049 if (!path) {
4050 err = -ENOMEM;
4051 goto out;
4052 }
4053
4054 inode = lookup_free_space_inode(rc->block_group, path);
4055 btrfs_free_path(path);
4056
4057 if (!IS_ERR(inode))
4058 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4059 else
4060 ret = PTR_ERR(inode);
4061
4062 if (ret && ret != -ENOENT) {
4063 err = ret;
4064 goto out;
4065 }
4066
4067 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4068 if (IS_ERR(rc->data_inode)) {
4069 err = PTR_ERR(rc->data_inode);
4070 rc->data_inode = NULL;
4071 goto out;
4072 }
4073
4074 describe_relocation(rc->block_group);
4075
4076 btrfs_wait_block_group_reservations(rc->block_group);
4077 btrfs_wait_nocow_writers(rc->block_group);
4078 btrfs_wait_ordered_roots(fs_info, U64_MAX, rc->block_group);
4079
4080 ret = btrfs_zone_finish(rc->block_group);
4081 WARN_ON(ret && ret != -EAGAIN);
4082
4083 while (1) {
4084 enum reloc_stage 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(BTRFS_I(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 ret2;
4176 int ret = 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 goto out;
4192 if (ret > 0) {
4193 if (path->slots[0] == 0)
4194 break;
4195 path->slots[0]--;
4196 }
4197 ret = 0;
4198 leaf = path->nodes[0];
4199 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4200 btrfs_release_path(path);
4201
4202 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4203 key.type != BTRFS_ROOT_ITEM_KEY)
4204 break;
4205
4206 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
4207 if (IS_ERR(reloc_root)) {
4208 ret = PTR_ERR(reloc_root);
4209 goto out;
4210 }
4211
4212 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
4213 list_add(&reloc_root->root_list, &reloc_roots);
4214
4215 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4216 fs_root = btrfs_get_fs_root(fs_info,
4217 reloc_root->root_key.offset, false);
4218 if (IS_ERR(fs_root)) {
4219 ret = PTR_ERR(fs_root);
4220 if (ret != -ENOENT)
4221 goto out;
4222 ret = mark_garbage_root(reloc_root);
4223 if (ret < 0)
4224 goto out;
4225 ret = 0;
4226 } else {
4227 btrfs_put_root(fs_root);
4228 }
4229 }
4230
4231 if (key.offset == 0)
4232 break;
4233
4234 key.offset--;
4235 }
4236 btrfs_release_path(path);
4237
4238 if (list_empty(&reloc_roots))
4239 goto out;
4240
4241 rc = alloc_reloc_control(fs_info);
4242 if (!rc) {
4243 ret = -ENOMEM;
4244 goto out;
4245 }
4246
4247 ret = reloc_chunk_start(fs_info);
4248 if (ret < 0)
4249 goto out_end;
4250
4251 rc->extent_root = btrfs_extent_root(fs_info, 0);
4252
4253 set_reloc_control(rc);
4254
4255 trans = btrfs_join_transaction(rc->extent_root);
4256 if (IS_ERR(trans)) {
4257 ret = PTR_ERR(trans);
4258 goto out_unset;
4259 }
4260
4261 rc->merge_reloc_tree = true;
4262
4263 while (!list_empty(&reloc_roots)) {
4264 reloc_root = list_entry(reloc_roots.next,
4265 struct btrfs_root, root_list);
4266 list_del(&reloc_root->root_list);
4267
4268 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4269 list_add_tail(&reloc_root->root_list,
4270 &rc->reloc_roots);
4271 continue;
4272 }
4273
4274 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
4275 false);
4276 if (IS_ERR(fs_root)) {
4277 ret = PTR_ERR(fs_root);
4278 list_add_tail(&reloc_root->root_list, &reloc_roots);
4279 btrfs_end_transaction(trans);
4280 goto out_unset;
4281 }
4282
4283 ret = __add_reloc_root(reloc_root);
4284 ASSERT(ret != -EEXIST);
4285 if (ret) {
4286 list_add_tail(&reloc_root->root_list, &reloc_roots);
4287 btrfs_put_root(fs_root);
4288 btrfs_end_transaction(trans);
4289 goto out_unset;
4290 }
4291 fs_root->reloc_root = btrfs_grab_root(reloc_root);
4292 btrfs_put_root(fs_root);
4293 }
4294
4295 ret = btrfs_commit_transaction(trans);
4296 if (ret)
4297 goto out_unset;
4298
4299 merge_reloc_roots(rc);
4300
4301 unset_reloc_control(rc);
4302
4303 trans = btrfs_join_transaction(rc->extent_root);
4304 if (IS_ERR(trans)) {
4305 ret = PTR_ERR(trans);
4306 goto out_clean;
4307 }
4308 ret = btrfs_commit_transaction(trans);
4309out_clean:
4310 ret2 = clean_dirty_subvols(rc);
4311 if (ret2 < 0 && !ret)
4312 ret = ret2;
4313out_unset:
4314 unset_reloc_control(rc);
4315out_end:
4316 reloc_chunk_end(fs_info);
4317 free_reloc_control(rc);
4318out:
4319 free_reloc_roots(&reloc_roots);
4320
4321 btrfs_free_path(path);
4322
4323 if (ret == 0) {
4324 /* cleanup orphan inode in data relocation tree */
4325 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
4326 ASSERT(fs_root);
4327 ret = btrfs_orphan_cleanup(fs_root);
4328 btrfs_put_root(fs_root);
4329 }
4330 return ret;
4331}
4332
4333/*
4334 * helper to add ordered checksum for data relocation.
4335 *
4336 * cloning checksum properly handles the nodatasum extents.
4337 * it also saves CPU time to re-calculate the checksum.
4338 */
4339int btrfs_reloc_clone_csums(struct btrfs_ordered_extent *ordered)
4340{
4341 struct btrfs_inode *inode = ordered->inode;
4342 struct btrfs_fs_info *fs_info = inode->root->fs_info;
4343 u64 disk_bytenr = ordered->file_offset + inode->reloc_block_group_start;
4344 struct btrfs_root *csum_root = btrfs_csum_root(fs_info, disk_bytenr);
4345 LIST_HEAD(list);
4346 int ret;
4347
4348 ret = btrfs_lookup_csums_list(csum_root, disk_bytenr,
4349 disk_bytenr + ordered->num_bytes - 1,
4350 &list, false);
4351 if (ret < 0) {
4352 btrfs_mark_ordered_extent_error(ordered);
4353 return ret;
4354 }
4355
4356 while (!list_empty(&list)) {
4357 struct btrfs_ordered_sum *sums =
4358 list_entry(list.next, struct btrfs_ordered_sum, list);
4359
4360 list_del_init(&sums->list);
4361
4362 /*
4363 * We need to offset the new_bytenr based on where the csum is.
4364 * We need to do this because we will read in entire prealloc
4365 * extents but we may have written to say the middle of the
4366 * prealloc extent, so we need to make sure the csum goes with
4367 * the right disk offset.
4368 *
4369 * We can do this because the data reloc inode refers strictly
4370 * to the on disk bytes, so we don't have to worry about
4371 * disk_len vs real len like with real inodes since it's all
4372 * disk length.
4373 */
4374 sums->logical = ordered->disk_bytenr + sums->logical - disk_bytenr;
4375 btrfs_add_ordered_sum(ordered, sums);
4376 }
4377
4378 return 0;
4379}
4380
4381int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4382 struct btrfs_root *root,
4383 const struct extent_buffer *buf,
4384 struct extent_buffer *cow)
4385{
4386 struct btrfs_fs_info *fs_info = root->fs_info;
4387 struct reloc_control *rc;
4388 struct btrfs_backref_node *node;
4389 int first_cow = 0;
4390 int level;
4391 int ret = 0;
4392
4393 rc = fs_info->reloc_ctl;
4394 if (!rc)
4395 return 0;
4396
4397 BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root));
4398
4399 level = btrfs_header_level(buf);
4400 if (btrfs_header_generation(buf) <=
4401 btrfs_root_last_snapshot(&root->root_item))
4402 first_cow = 1;
4403
4404 if (btrfs_root_id(root) == BTRFS_TREE_RELOC_OBJECTID && rc->create_reloc_tree) {
4405 WARN_ON(!first_cow && level == 0);
4406
4407 node = rc->backref_cache.path[level];
4408
4409 /*
4410 * If node->bytenr != buf->start and node->new_bytenr !=
4411 * buf->start then we've got the wrong backref node for what we
4412 * expected to see here and the cache is incorrect.
4413 */
4414 if (unlikely(node->bytenr != buf->start && node->new_bytenr != buf->start)) {
4415 btrfs_err(fs_info,
4416"bytenr %llu was found but our backref cache was expecting %llu or %llu",
4417 buf->start, node->bytenr, node->new_bytenr);
4418 return -EUCLEAN;
4419 }
4420
4421 btrfs_backref_drop_node_buffer(node);
4422 atomic_inc(&cow->refs);
4423 node->eb = cow;
4424 node->new_bytenr = cow->start;
4425
4426 if (!node->pending) {
4427 list_move_tail(&node->list,
4428 &rc->backref_cache.pending[level]);
4429 node->pending = 1;
4430 }
4431
4432 if (first_cow)
4433 mark_block_processed(rc, node);
4434
4435 if (first_cow && level > 0)
4436 rc->nodes_relocated += buf->len;
4437 }
4438
4439 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4440 ret = replace_file_extents(trans, rc, root, cow);
4441 return ret;
4442}
4443
4444/*
4445 * called before creating snapshot. it calculates metadata reservation
4446 * required for relocating tree blocks in the snapshot
4447 */
4448void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4449 u64 *bytes_to_reserve)
4450{
4451 struct btrfs_root *root = pending->root;
4452 struct reloc_control *rc = root->fs_info->reloc_ctl;
4453
4454 if (!rc || !have_reloc_root(root))
4455 return;
4456
4457 if (!rc->merge_reloc_tree)
4458 return;
4459
4460 root = root->reloc_root;
4461 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4462 /*
4463 * relocation is in the stage of merging trees. the space
4464 * used by merging a reloc tree is twice the size of
4465 * relocated tree nodes in the worst case. half for cowing
4466 * the reloc tree, half for cowing the fs tree. the space
4467 * used by cowing the reloc tree will be freed after the
4468 * tree is dropped. if we create snapshot, cowing the fs
4469 * tree may use more space than it frees. so we need
4470 * reserve extra space.
4471 */
4472 *bytes_to_reserve += rc->nodes_relocated;
4473}
4474
4475/*
4476 * called after snapshot is created. migrate block reservation
4477 * and create reloc root for the newly created snapshot
4478 *
4479 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4480 * references held on the reloc_root, one for root->reloc_root and one for
4481 * rc->reloc_roots.
4482 */
4483int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4484 struct btrfs_pending_snapshot *pending)
4485{
4486 struct btrfs_root *root = pending->root;
4487 struct btrfs_root *reloc_root;
4488 struct btrfs_root *new_root;
4489 struct reloc_control *rc = root->fs_info->reloc_ctl;
4490 int ret;
4491
4492 if (!rc || !have_reloc_root(root))
4493 return 0;
4494
4495 rc = root->fs_info->reloc_ctl;
4496 rc->merging_rsv_size += rc->nodes_relocated;
4497
4498 if (rc->merge_reloc_tree) {
4499 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4500 rc->block_rsv,
4501 rc->nodes_relocated, true);
4502 if (ret)
4503 return ret;
4504 }
4505
4506 new_root = pending->snap;
4507 reloc_root = create_reloc_root(trans, root->reloc_root, btrfs_root_id(new_root));
4508 if (IS_ERR(reloc_root))
4509 return PTR_ERR(reloc_root);
4510
4511 ret = __add_reloc_root(reloc_root);
4512 ASSERT(ret != -EEXIST);
4513 if (ret) {
4514 /* Pairs with create_reloc_root */
4515 btrfs_put_root(reloc_root);
4516 return ret;
4517 }
4518 new_root->reloc_root = btrfs_grab_root(reloc_root);
4519
4520 if (rc->create_reloc_tree)
4521 ret = clone_backref_node(trans, rc, root, reloc_root);
4522 return ret;
4523}
4524
4525/*
4526 * Get the current bytenr for the block group which is being relocated.
4527 *
4528 * Return U64_MAX if no running relocation.
4529 */
4530u64 btrfs_get_reloc_bg_bytenr(const struct btrfs_fs_info *fs_info)
4531{
4532 u64 logical = U64_MAX;
4533
4534 lockdep_assert_held(&fs_info->reloc_mutex);
4535
4536 if (fs_info->reloc_ctl && fs_info->reloc_ctl->block_group)
4537 logical = fs_info->reloc_ctl->block_group->start;
4538 return logical;
4539}