Loading...
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/pagemap.h>
8#include <linux/writeback.h>
9#include <linux/blkdev.h>
10#include <linux/rbtree.h>
11#include <linux/slab.h>
12#include "ctree.h"
13#include "disk-io.h"
14#include "transaction.h"
15#include "volumes.h"
16#include "locking.h"
17#include "btrfs_inode.h"
18#include "async-thread.h"
19#include "free-space-cache.h"
20#include "inode-map.h"
21#include "qgroup.h"
22#include "print-tree.h"
23#include "delalloc-space.h"
24#include "block-group.h"
25
26/*
27 * backref_node, mapping_node and tree_block start with this
28 */
29struct tree_entry {
30 struct rb_node rb_node;
31 u64 bytenr;
32};
33
34/*
35 * present a tree block in the backref cache
36 */
37struct backref_node {
38 struct rb_node rb_node;
39 u64 bytenr;
40
41 u64 new_bytenr;
42 /* objectid of tree block owner, can be not uptodate */
43 u64 owner;
44 /* link to pending, changed or detached list */
45 struct list_head list;
46 /* list of upper level blocks reference this block */
47 struct list_head upper;
48 /* list of child blocks in the cache */
49 struct list_head lower;
50 /* NULL if this node is not tree root */
51 struct btrfs_root *root;
52 /* extent buffer got by COW the block */
53 struct extent_buffer *eb;
54 /* level of tree block */
55 unsigned int level:8;
56 /* is the block in non-reference counted tree */
57 unsigned int cowonly:1;
58 /* 1 if no child node in the cache */
59 unsigned int lowest:1;
60 /* is the extent buffer locked */
61 unsigned int locked:1;
62 /* has the block been processed */
63 unsigned int processed:1;
64 /* have backrefs of this block been checked */
65 unsigned int checked:1;
66 /*
67 * 1 if corresponding block has been cowed but some upper
68 * level block pointers may not point to the new location
69 */
70 unsigned int pending:1;
71 /*
72 * 1 if the backref node isn't connected to any other
73 * backref node.
74 */
75 unsigned int detached:1;
76};
77
78/*
79 * present a block pointer in the backref cache
80 */
81struct backref_edge {
82 struct list_head list[2];
83 struct backref_node *node[2];
84};
85
86#define LOWER 0
87#define UPPER 1
88#define RELOCATION_RESERVED_NODES 256
89
90struct backref_cache {
91 /* red black tree of all backref nodes in the cache */
92 struct rb_root rb_root;
93 /* for passing backref nodes to btrfs_reloc_cow_block */
94 struct backref_node *path[BTRFS_MAX_LEVEL];
95 /*
96 * list of blocks that have been cowed but some block
97 * pointers in upper level blocks may not reflect the
98 * new location
99 */
100 struct list_head pending[BTRFS_MAX_LEVEL];
101 /* list of backref nodes with no child node */
102 struct list_head leaves;
103 /* list of blocks that have been cowed in current transaction */
104 struct list_head changed;
105 /* list of detached backref node. */
106 struct list_head detached;
107
108 u64 last_trans;
109
110 int nr_nodes;
111 int nr_edges;
112};
113
114/*
115 * map address of tree root to tree
116 */
117struct mapping_node {
118 struct rb_node rb_node;
119 u64 bytenr;
120 void *data;
121};
122
123struct mapping_tree {
124 struct rb_root rb_root;
125 spinlock_t lock;
126};
127
128/*
129 * present a tree block to process
130 */
131struct tree_block {
132 struct rb_node rb_node;
133 u64 bytenr;
134 struct btrfs_key key;
135 unsigned int level:8;
136 unsigned int key_ready:1;
137};
138
139#define MAX_EXTENTS 128
140
141struct file_extent_cluster {
142 u64 start;
143 u64 end;
144 u64 boundary[MAX_EXTENTS];
145 unsigned int nr;
146};
147
148struct reloc_control {
149 /* block group to relocate */
150 struct btrfs_block_group_cache *block_group;
151 /* extent tree */
152 struct btrfs_root *extent_root;
153 /* inode for moving data */
154 struct inode *data_inode;
155
156 struct btrfs_block_rsv *block_rsv;
157
158 struct backref_cache backref_cache;
159
160 struct file_extent_cluster cluster;
161 /* tree blocks have been processed */
162 struct extent_io_tree processed_blocks;
163 /* map start of tree root to corresponding reloc tree */
164 struct mapping_tree reloc_root_tree;
165 /* list of reloc trees */
166 struct list_head reloc_roots;
167 /* list of subvolume trees that get relocated */
168 struct list_head dirty_subvol_roots;
169 /* size of metadata reservation for merging reloc trees */
170 u64 merging_rsv_size;
171 /* size of relocated tree nodes */
172 u64 nodes_relocated;
173 /* reserved size for block group relocation*/
174 u64 reserved_bytes;
175
176 u64 search_start;
177 u64 extents_found;
178
179 unsigned int stage:8;
180 unsigned int create_reloc_tree:1;
181 unsigned int merge_reloc_tree:1;
182 unsigned int found_file_extent:1;
183};
184
185/* stages of data relocation */
186#define MOVE_DATA_EXTENTS 0
187#define UPDATE_DATA_PTRS 1
188
189static void remove_backref_node(struct backref_cache *cache,
190 struct backref_node *node);
191static void __mark_block_processed(struct reloc_control *rc,
192 struct backref_node *node);
193
194static void mapping_tree_init(struct mapping_tree *tree)
195{
196 tree->rb_root = RB_ROOT;
197 spin_lock_init(&tree->lock);
198}
199
200static void backref_cache_init(struct backref_cache *cache)
201{
202 int i;
203 cache->rb_root = RB_ROOT;
204 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
205 INIT_LIST_HEAD(&cache->pending[i]);
206 INIT_LIST_HEAD(&cache->changed);
207 INIT_LIST_HEAD(&cache->detached);
208 INIT_LIST_HEAD(&cache->leaves);
209}
210
211static void backref_cache_cleanup(struct backref_cache *cache)
212{
213 struct backref_node *node;
214 int i;
215
216 while (!list_empty(&cache->detached)) {
217 node = list_entry(cache->detached.next,
218 struct backref_node, list);
219 remove_backref_node(cache, node);
220 }
221
222 while (!list_empty(&cache->leaves)) {
223 node = list_entry(cache->leaves.next,
224 struct backref_node, lower);
225 remove_backref_node(cache, node);
226 }
227
228 cache->last_trans = 0;
229
230 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
231 ASSERT(list_empty(&cache->pending[i]));
232 ASSERT(list_empty(&cache->changed));
233 ASSERT(list_empty(&cache->detached));
234 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
235 ASSERT(!cache->nr_nodes);
236 ASSERT(!cache->nr_edges);
237}
238
239static struct backref_node *alloc_backref_node(struct backref_cache *cache)
240{
241 struct backref_node *node;
242
243 node = kzalloc(sizeof(*node), GFP_NOFS);
244 if (node) {
245 INIT_LIST_HEAD(&node->list);
246 INIT_LIST_HEAD(&node->upper);
247 INIT_LIST_HEAD(&node->lower);
248 RB_CLEAR_NODE(&node->rb_node);
249 cache->nr_nodes++;
250 }
251 return node;
252}
253
254static void free_backref_node(struct backref_cache *cache,
255 struct backref_node *node)
256{
257 if (node) {
258 cache->nr_nodes--;
259 kfree(node);
260 }
261}
262
263static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
264{
265 struct backref_edge *edge;
266
267 edge = kzalloc(sizeof(*edge), GFP_NOFS);
268 if (edge)
269 cache->nr_edges++;
270 return edge;
271}
272
273static void free_backref_edge(struct backref_cache *cache,
274 struct backref_edge *edge)
275{
276 if (edge) {
277 cache->nr_edges--;
278 kfree(edge);
279 }
280}
281
282static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
283 struct rb_node *node)
284{
285 struct rb_node **p = &root->rb_node;
286 struct rb_node *parent = NULL;
287 struct tree_entry *entry;
288
289 while (*p) {
290 parent = *p;
291 entry = rb_entry(parent, struct tree_entry, rb_node);
292
293 if (bytenr < entry->bytenr)
294 p = &(*p)->rb_left;
295 else if (bytenr > entry->bytenr)
296 p = &(*p)->rb_right;
297 else
298 return parent;
299 }
300
301 rb_link_node(node, parent, p);
302 rb_insert_color(node, root);
303 return NULL;
304}
305
306static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
307{
308 struct rb_node *n = root->rb_node;
309 struct tree_entry *entry;
310
311 while (n) {
312 entry = rb_entry(n, struct tree_entry, rb_node);
313
314 if (bytenr < entry->bytenr)
315 n = n->rb_left;
316 else if (bytenr > entry->bytenr)
317 n = n->rb_right;
318 else
319 return n;
320 }
321 return NULL;
322}
323
324static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
325{
326
327 struct btrfs_fs_info *fs_info = NULL;
328 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
329 rb_node);
330 if (bnode->root)
331 fs_info = bnode->root->fs_info;
332 btrfs_panic(fs_info, errno,
333 "Inconsistency in backref cache found at offset %llu",
334 bytenr);
335}
336
337/*
338 * walk up backref nodes until reach node presents tree root
339 */
340static struct backref_node *walk_up_backref(struct backref_node *node,
341 struct backref_edge *edges[],
342 int *index)
343{
344 struct backref_edge *edge;
345 int idx = *index;
346
347 while (!list_empty(&node->upper)) {
348 edge = list_entry(node->upper.next,
349 struct backref_edge, list[LOWER]);
350 edges[idx++] = edge;
351 node = edge->node[UPPER];
352 }
353 BUG_ON(node->detached);
354 *index = idx;
355 return node;
356}
357
358/*
359 * walk down backref nodes to find start of next reference path
360 */
361static struct backref_node *walk_down_backref(struct backref_edge *edges[],
362 int *index)
363{
364 struct backref_edge *edge;
365 struct backref_node *lower;
366 int idx = *index;
367
368 while (idx > 0) {
369 edge = edges[idx - 1];
370 lower = edge->node[LOWER];
371 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
372 idx--;
373 continue;
374 }
375 edge = list_entry(edge->list[LOWER].next,
376 struct backref_edge, list[LOWER]);
377 edges[idx - 1] = edge;
378 *index = idx;
379 return edge->node[UPPER];
380 }
381 *index = 0;
382 return NULL;
383}
384
385static void unlock_node_buffer(struct backref_node *node)
386{
387 if (node->locked) {
388 btrfs_tree_unlock(node->eb);
389 node->locked = 0;
390 }
391}
392
393static void drop_node_buffer(struct backref_node *node)
394{
395 if (node->eb) {
396 unlock_node_buffer(node);
397 free_extent_buffer(node->eb);
398 node->eb = NULL;
399 }
400}
401
402static void drop_backref_node(struct backref_cache *tree,
403 struct backref_node *node)
404{
405 BUG_ON(!list_empty(&node->upper));
406
407 drop_node_buffer(node);
408 list_del(&node->list);
409 list_del(&node->lower);
410 if (!RB_EMPTY_NODE(&node->rb_node))
411 rb_erase(&node->rb_node, &tree->rb_root);
412 free_backref_node(tree, node);
413}
414
415/*
416 * remove a backref node from the backref cache
417 */
418static void remove_backref_node(struct backref_cache *cache,
419 struct backref_node *node)
420{
421 struct backref_node *upper;
422 struct backref_edge *edge;
423
424 if (!node)
425 return;
426
427 BUG_ON(!node->lowest && !node->detached);
428 while (!list_empty(&node->upper)) {
429 edge = list_entry(node->upper.next, struct backref_edge,
430 list[LOWER]);
431 upper = edge->node[UPPER];
432 list_del(&edge->list[LOWER]);
433 list_del(&edge->list[UPPER]);
434 free_backref_edge(cache, edge);
435
436 if (RB_EMPTY_NODE(&upper->rb_node)) {
437 BUG_ON(!list_empty(&node->upper));
438 drop_backref_node(cache, node);
439 node = upper;
440 node->lowest = 1;
441 continue;
442 }
443 /*
444 * add the node to leaf node list if no other
445 * child block cached.
446 */
447 if (list_empty(&upper->lower)) {
448 list_add_tail(&upper->lower, &cache->leaves);
449 upper->lowest = 1;
450 }
451 }
452
453 drop_backref_node(cache, node);
454}
455
456static void update_backref_node(struct backref_cache *cache,
457 struct backref_node *node, u64 bytenr)
458{
459 struct rb_node *rb_node;
460 rb_erase(&node->rb_node, &cache->rb_root);
461 node->bytenr = bytenr;
462 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
463 if (rb_node)
464 backref_tree_panic(rb_node, -EEXIST, bytenr);
465}
466
467/*
468 * update backref cache after a transaction commit
469 */
470static int update_backref_cache(struct btrfs_trans_handle *trans,
471 struct backref_cache *cache)
472{
473 struct backref_node *node;
474 int level = 0;
475
476 if (cache->last_trans == 0) {
477 cache->last_trans = trans->transid;
478 return 0;
479 }
480
481 if (cache->last_trans == trans->transid)
482 return 0;
483
484 /*
485 * detached nodes are used to avoid unnecessary backref
486 * lookup. transaction commit changes the extent tree.
487 * so the detached nodes are no longer useful.
488 */
489 while (!list_empty(&cache->detached)) {
490 node = list_entry(cache->detached.next,
491 struct backref_node, list);
492 remove_backref_node(cache, node);
493 }
494
495 while (!list_empty(&cache->changed)) {
496 node = list_entry(cache->changed.next,
497 struct backref_node, list);
498 list_del_init(&node->list);
499 BUG_ON(node->pending);
500 update_backref_node(cache, node, node->new_bytenr);
501 }
502
503 /*
504 * some nodes can be left in the pending list if there were
505 * errors during processing the pending nodes.
506 */
507 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
508 list_for_each_entry(node, &cache->pending[level], list) {
509 BUG_ON(!node->pending);
510 if (node->bytenr == node->new_bytenr)
511 continue;
512 update_backref_node(cache, node, node->new_bytenr);
513 }
514 }
515
516 cache->last_trans = 0;
517 return 1;
518}
519
520
521static int should_ignore_root(struct btrfs_root *root)
522{
523 struct btrfs_root *reloc_root;
524
525 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
526 return 0;
527
528 reloc_root = root->reloc_root;
529 if (!reloc_root)
530 return 0;
531
532 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
533 root->fs_info->running_transaction->transid - 1)
534 return 0;
535 /*
536 * if there is reloc tree and it was created in previous
537 * transaction backref lookup can find the reloc tree,
538 * so backref node for the fs tree root is useless for
539 * relocation.
540 */
541 return 1;
542}
543/*
544 * find reloc tree by address of tree root
545 */
546static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
547 u64 bytenr)
548{
549 struct rb_node *rb_node;
550 struct mapping_node *node;
551 struct btrfs_root *root = NULL;
552
553 spin_lock(&rc->reloc_root_tree.lock);
554 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
555 if (rb_node) {
556 node = rb_entry(rb_node, struct mapping_node, rb_node);
557 root = (struct btrfs_root *)node->data;
558 }
559 spin_unlock(&rc->reloc_root_tree.lock);
560 return root;
561}
562
563static int is_cowonly_root(u64 root_objectid)
564{
565 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
566 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
567 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
568 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
569 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
570 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
571 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
572 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
573 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
574 return 1;
575 return 0;
576}
577
578static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
579 u64 root_objectid)
580{
581 struct btrfs_key key;
582
583 key.objectid = root_objectid;
584 key.type = BTRFS_ROOT_ITEM_KEY;
585 if (is_cowonly_root(root_objectid))
586 key.offset = 0;
587 else
588 key.offset = (u64)-1;
589
590 return btrfs_get_fs_root(fs_info, &key, false);
591}
592
593static noinline_for_stack
594int find_inline_backref(struct extent_buffer *leaf, int slot,
595 unsigned long *ptr, unsigned long *end)
596{
597 struct btrfs_key key;
598 struct btrfs_extent_item *ei;
599 struct btrfs_tree_block_info *bi;
600 u32 item_size;
601
602 btrfs_item_key_to_cpu(leaf, &key, slot);
603
604 item_size = btrfs_item_size_nr(leaf, slot);
605 if (item_size < sizeof(*ei)) {
606 btrfs_print_v0_err(leaf->fs_info);
607 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
608 return 1;
609 }
610 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
611 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
612 BTRFS_EXTENT_FLAG_TREE_BLOCK));
613
614 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
615 item_size <= sizeof(*ei) + sizeof(*bi)) {
616 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
617 return 1;
618 }
619 if (key.type == BTRFS_METADATA_ITEM_KEY &&
620 item_size <= sizeof(*ei)) {
621 WARN_ON(item_size < sizeof(*ei));
622 return 1;
623 }
624
625 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
626 bi = (struct btrfs_tree_block_info *)(ei + 1);
627 *ptr = (unsigned long)(bi + 1);
628 } else {
629 *ptr = (unsigned long)(ei + 1);
630 }
631 *end = (unsigned long)ei + item_size;
632 return 0;
633}
634
635/*
636 * build backref tree for a given tree block. root of the backref tree
637 * corresponds the tree block, leaves of the backref tree correspond
638 * roots of b-trees that reference the tree block.
639 *
640 * the basic idea of this function is check backrefs of a given block
641 * to find upper level blocks that reference the block, and then check
642 * backrefs of these upper level blocks recursively. the recursion stop
643 * when tree root is reached or backrefs for the block is cached.
644 *
645 * NOTE: if we find backrefs for a block are cached, we know backrefs
646 * for all upper level blocks that directly/indirectly reference the
647 * block are also cached.
648 */
649static noinline_for_stack
650struct backref_node *build_backref_tree(struct reloc_control *rc,
651 struct btrfs_key *node_key,
652 int level, u64 bytenr)
653{
654 struct backref_cache *cache = &rc->backref_cache;
655 struct btrfs_path *path1; /* For searching extent root */
656 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
657 struct extent_buffer *eb;
658 struct btrfs_root *root;
659 struct backref_node *cur;
660 struct backref_node *upper;
661 struct backref_node *lower;
662 struct backref_node *node = NULL;
663 struct backref_node *exist = NULL;
664 struct backref_edge *edge;
665 struct rb_node *rb_node;
666 struct btrfs_key key;
667 unsigned long end;
668 unsigned long ptr;
669 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
670 LIST_HEAD(useless);
671 int cowonly;
672 int ret;
673 int err = 0;
674 bool need_check = true;
675
676 path1 = btrfs_alloc_path();
677 path2 = btrfs_alloc_path();
678 if (!path1 || !path2) {
679 err = -ENOMEM;
680 goto out;
681 }
682 path1->reada = READA_FORWARD;
683 path2->reada = READA_FORWARD;
684
685 node = alloc_backref_node(cache);
686 if (!node) {
687 err = -ENOMEM;
688 goto out;
689 }
690
691 node->bytenr = bytenr;
692 node->level = level;
693 node->lowest = 1;
694 cur = node;
695again:
696 end = 0;
697 ptr = 0;
698 key.objectid = cur->bytenr;
699 key.type = BTRFS_METADATA_ITEM_KEY;
700 key.offset = (u64)-1;
701
702 path1->search_commit_root = 1;
703 path1->skip_locking = 1;
704 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
705 0, 0);
706 if (ret < 0) {
707 err = ret;
708 goto out;
709 }
710 ASSERT(ret);
711 ASSERT(path1->slots[0]);
712
713 path1->slots[0]--;
714
715 WARN_ON(cur->checked);
716 if (!list_empty(&cur->upper)) {
717 /*
718 * the backref was added previously when processing
719 * backref of type BTRFS_TREE_BLOCK_REF_KEY
720 */
721 ASSERT(list_is_singular(&cur->upper));
722 edge = list_entry(cur->upper.next, struct backref_edge,
723 list[LOWER]);
724 ASSERT(list_empty(&edge->list[UPPER]));
725 exist = edge->node[UPPER];
726 /*
727 * add the upper level block to pending list if we need
728 * check its backrefs
729 */
730 if (!exist->checked)
731 list_add_tail(&edge->list[UPPER], &list);
732 } else {
733 exist = NULL;
734 }
735
736 while (1) {
737 cond_resched();
738 eb = path1->nodes[0];
739
740 if (ptr >= end) {
741 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
742 ret = btrfs_next_leaf(rc->extent_root, path1);
743 if (ret < 0) {
744 err = ret;
745 goto out;
746 }
747 if (ret > 0)
748 break;
749 eb = path1->nodes[0];
750 }
751
752 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
753 if (key.objectid != cur->bytenr) {
754 WARN_ON(exist);
755 break;
756 }
757
758 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
759 key.type == BTRFS_METADATA_ITEM_KEY) {
760 ret = find_inline_backref(eb, path1->slots[0],
761 &ptr, &end);
762 if (ret)
763 goto next;
764 }
765 }
766
767 if (ptr < end) {
768 /* update key for inline back ref */
769 struct btrfs_extent_inline_ref *iref;
770 int type;
771 iref = (struct btrfs_extent_inline_ref *)ptr;
772 type = btrfs_get_extent_inline_ref_type(eb, iref,
773 BTRFS_REF_TYPE_BLOCK);
774 if (type == BTRFS_REF_TYPE_INVALID) {
775 err = -EUCLEAN;
776 goto out;
777 }
778 key.type = type;
779 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
780
781 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
782 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
783 }
784
785 /*
786 * Parent node found and matches current inline ref, no need to
787 * rebuild this node for this inline ref.
788 */
789 if (exist &&
790 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
791 exist->owner == key.offset) ||
792 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
793 exist->bytenr == key.offset))) {
794 exist = NULL;
795 goto next;
796 }
797
798 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
799 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
800 if (key.objectid == key.offset) {
801 /*
802 * Only root blocks of reloc trees use backref
803 * pointing to itself.
804 */
805 root = find_reloc_root(rc, cur->bytenr);
806 ASSERT(root);
807 cur->root = root;
808 break;
809 }
810
811 edge = alloc_backref_edge(cache);
812 if (!edge) {
813 err = -ENOMEM;
814 goto out;
815 }
816 rb_node = tree_search(&cache->rb_root, key.offset);
817 if (!rb_node) {
818 upper = alloc_backref_node(cache);
819 if (!upper) {
820 free_backref_edge(cache, edge);
821 err = -ENOMEM;
822 goto out;
823 }
824 upper->bytenr = key.offset;
825 upper->level = cur->level + 1;
826 /*
827 * backrefs for the upper level block isn't
828 * cached, add the block to pending list
829 */
830 list_add_tail(&edge->list[UPPER], &list);
831 } else {
832 upper = rb_entry(rb_node, struct backref_node,
833 rb_node);
834 ASSERT(upper->checked);
835 INIT_LIST_HEAD(&edge->list[UPPER]);
836 }
837 list_add_tail(&edge->list[LOWER], &cur->upper);
838 edge->node[LOWER] = cur;
839 edge->node[UPPER] = upper;
840
841 goto next;
842 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
843 err = -EINVAL;
844 btrfs_print_v0_err(rc->extent_root->fs_info);
845 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
846 NULL);
847 goto out;
848 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
849 goto next;
850 }
851
852 /*
853 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
854 * means the root objectid. We need to search the tree to get
855 * its parent bytenr.
856 */
857 root = read_fs_root(rc->extent_root->fs_info, key.offset);
858 if (IS_ERR(root)) {
859 err = PTR_ERR(root);
860 goto out;
861 }
862
863 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
864 cur->cowonly = 1;
865
866 if (btrfs_root_level(&root->root_item) == cur->level) {
867 /* tree root */
868 ASSERT(btrfs_root_bytenr(&root->root_item) ==
869 cur->bytenr);
870 if (should_ignore_root(root))
871 list_add(&cur->list, &useless);
872 else
873 cur->root = root;
874 break;
875 }
876
877 level = cur->level + 1;
878
879 /* Search the tree to find parent blocks referring the block. */
880 path2->search_commit_root = 1;
881 path2->skip_locking = 1;
882 path2->lowest_level = level;
883 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
884 path2->lowest_level = 0;
885 if (ret < 0) {
886 err = ret;
887 goto out;
888 }
889 if (ret > 0 && path2->slots[level] > 0)
890 path2->slots[level]--;
891
892 eb = path2->nodes[level];
893 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
894 cur->bytenr) {
895 btrfs_err(root->fs_info,
896 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
897 cur->bytenr, level - 1,
898 root->root_key.objectid,
899 node_key->objectid, node_key->type,
900 node_key->offset);
901 err = -ENOENT;
902 goto out;
903 }
904 lower = cur;
905 need_check = true;
906
907 /* Add all nodes and edges in the path */
908 for (; level < BTRFS_MAX_LEVEL; level++) {
909 if (!path2->nodes[level]) {
910 ASSERT(btrfs_root_bytenr(&root->root_item) ==
911 lower->bytenr);
912 if (should_ignore_root(root))
913 list_add(&lower->list, &useless);
914 else
915 lower->root = root;
916 break;
917 }
918
919 edge = alloc_backref_edge(cache);
920 if (!edge) {
921 err = -ENOMEM;
922 goto out;
923 }
924
925 eb = path2->nodes[level];
926 rb_node = tree_search(&cache->rb_root, eb->start);
927 if (!rb_node) {
928 upper = alloc_backref_node(cache);
929 if (!upper) {
930 free_backref_edge(cache, edge);
931 err = -ENOMEM;
932 goto out;
933 }
934 upper->bytenr = eb->start;
935 upper->owner = btrfs_header_owner(eb);
936 upper->level = lower->level + 1;
937 if (!test_bit(BTRFS_ROOT_REF_COWS,
938 &root->state))
939 upper->cowonly = 1;
940
941 /*
942 * if we know the block isn't shared
943 * we can void checking its backrefs.
944 */
945 if (btrfs_block_can_be_shared(root, eb))
946 upper->checked = 0;
947 else
948 upper->checked = 1;
949
950 /*
951 * add the block to pending list if we
952 * need check its backrefs, we only do this once
953 * while walking up a tree as we will catch
954 * anything else later on.
955 */
956 if (!upper->checked && need_check) {
957 need_check = false;
958 list_add_tail(&edge->list[UPPER],
959 &list);
960 } else {
961 if (upper->checked)
962 need_check = true;
963 INIT_LIST_HEAD(&edge->list[UPPER]);
964 }
965 } else {
966 upper = rb_entry(rb_node, struct backref_node,
967 rb_node);
968 ASSERT(upper->checked);
969 INIT_LIST_HEAD(&edge->list[UPPER]);
970 if (!upper->owner)
971 upper->owner = btrfs_header_owner(eb);
972 }
973 list_add_tail(&edge->list[LOWER], &lower->upper);
974 edge->node[LOWER] = lower;
975 edge->node[UPPER] = upper;
976
977 if (rb_node)
978 break;
979 lower = upper;
980 upper = NULL;
981 }
982 btrfs_release_path(path2);
983next:
984 if (ptr < end) {
985 ptr += btrfs_extent_inline_ref_size(key.type);
986 if (ptr >= end) {
987 WARN_ON(ptr > end);
988 ptr = 0;
989 end = 0;
990 }
991 }
992 if (ptr >= end)
993 path1->slots[0]++;
994 }
995 btrfs_release_path(path1);
996
997 cur->checked = 1;
998 WARN_ON(exist);
999
1000 /* the pending list isn't empty, take the first block to process */
1001 if (!list_empty(&list)) {
1002 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1003 list_del_init(&edge->list[UPPER]);
1004 cur = edge->node[UPPER];
1005 goto again;
1006 }
1007
1008 /*
1009 * everything goes well, connect backref nodes and insert backref nodes
1010 * into the cache.
1011 */
1012 ASSERT(node->checked);
1013 cowonly = node->cowonly;
1014 if (!cowonly) {
1015 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1016 &node->rb_node);
1017 if (rb_node)
1018 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1019 list_add_tail(&node->lower, &cache->leaves);
1020 }
1021
1022 list_for_each_entry(edge, &node->upper, list[LOWER])
1023 list_add_tail(&edge->list[UPPER], &list);
1024
1025 while (!list_empty(&list)) {
1026 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1027 list_del_init(&edge->list[UPPER]);
1028 upper = edge->node[UPPER];
1029 if (upper->detached) {
1030 list_del(&edge->list[LOWER]);
1031 lower = edge->node[LOWER];
1032 free_backref_edge(cache, edge);
1033 if (list_empty(&lower->upper))
1034 list_add(&lower->list, &useless);
1035 continue;
1036 }
1037
1038 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1039 if (upper->lowest) {
1040 list_del_init(&upper->lower);
1041 upper->lowest = 0;
1042 }
1043
1044 list_add_tail(&edge->list[UPPER], &upper->lower);
1045 continue;
1046 }
1047
1048 if (!upper->checked) {
1049 /*
1050 * Still want to blow up for developers since this is a
1051 * logic bug.
1052 */
1053 ASSERT(0);
1054 err = -EINVAL;
1055 goto out;
1056 }
1057 if (cowonly != upper->cowonly) {
1058 ASSERT(0);
1059 err = -EINVAL;
1060 goto out;
1061 }
1062
1063 if (!cowonly) {
1064 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1065 &upper->rb_node);
1066 if (rb_node)
1067 backref_tree_panic(rb_node, -EEXIST,
1068 upper->bytenr);
1069 }
1070
1071 list_add_tail(&edge->list[UPPER], &upper->lower);
1072
1073 list_for_each_entry(edge, &upper->upper, list[LOWER])
1074 list_add_tail(&edge->list[UPPER], &list);
1075 }
1076 /*
1077 * process useless backref nodes. backref nodes for tree leaves
1078 * are deleted from the cache. backref nodes for upper level
1079 * tree blocks are left in the cache to avoid unnecessary backref
1080 * lookup.
1081 */
1082 while (!list_empty(&useless)) {
1083 upper = list_entry(useless.next, struct backref_node, list);
1084 list_del_init(&upper->list);
1085 ASSERT(list_empty(&upper->upper));
1086 if (upper == node)
1087 node = NULL;
1088 if (upper->lowest) {
1089 list_del_init(&upper->lower);
1090 upper->lowest = 0;
1091 }
1092 while (!list_empty(&upper->lower)) {
1093 edge = list_entry(upper->lower.next,
1094 struct backref_edge, list[UPPER]);
1095 list_del(&edge->list[UPPER]);
1096 list_del(&edge->list[LOWER]);
1097 lower = edge->node[LOWER];
1098 free_backref_edge(cache, edge);
1099
1100 if (list_empty(&lower->upper))
1101 list_add(&lower->list, &useless);
1102 }
1103 __mark_block_processed(rc, upper);
1104 if (upper->level > 0) {
1105 list_add(&upper->list, &cache->detached);
1106 upper->detached = 1;
1107 } else {
1108 rb_erase(&upper->rb_node, &cache->rb_root);
1109 free_backref_node(cache, upper);
1110 }
1111 }
1112out:
1113 btrfs_free_path(path1);
1114 btrfs_free_path(path2);
1115 if (err) {
1116 while (!list_empty(&useless)) {
1117 lower = list_entry(useless.next,
1118 struct backref_node, list);
1119 list_del_init(&lower->list);
1120 }
1121 while (!list_empty(&list)) {
1122 edge = list_first_entry(&list, struct backref_edge,
1123 list[UPPER]);
1124 list_del(&edge->list[UPPER]);
1125 list_del(&edge->list[LOWER]);
1126 lower = edge->node[LOWER];
1127 upper = edge->node[UPPER];
1128 free_backref_edge(cache, edge);
1129
1130 /*
1131 * Lower is no longer linked to any upper backref nodes
1132 * and isn't in the cache, we can free it ourselves.
1133 */
1134 if (list_empty(&lower->upper) &&
1135 RB_EMPTY_NODE(&lower->rb_node))
1136 list_add(&lower->list, &useless);
1137
1138 if (!RB_EMPTY_NODE(&upper->rb_node))
1139 continue;
1140
1141 /* Add this guy's upper edges to the list to process */
1142 list_for_each_entry(edge, &upper->upper, list[LOWER])
1143 list_add_tail(&edge->list[UPPER], &list);
1144 if (list_empty(&upper->upper))
1145 list_add(&upper->list, &useless);
1146 }
1147
1148 while (!list_empty(&useless)) {
1149 lower = list_entry(useless.next,
1150 struct backref_node, list);
1151 list_del_init(&lower->list);
1152 if (lower == node)
1153 node = NULL;
1154 free_backref_node(cache, lower);
1155 }
1156
1157 free_backref_node(cache, node);
1158 return ERR_PTR(err);
1159 }
1160 ASSERT(!node || !node->detached);
1161 return node;
1162}
1163
1164/*
1165 * helper to add backref node for the newly created snapshot.
1166 * the backref node is created by cloning backref node that
1167 * corresponds to root of source tree
1168 */
1169static int clone_backref_node(struct btrfs_trans_handle *trans,
1170 struct reloc_control *rc,
1171 struct btrfs_root *src,
1172 struct btrfs_root *dest)
1173{
1174 struct btrfs_root *reloc_root = src->reloc_root;
1175 struct backref_cache *cache = &rc->backref_cache;
1176 struct backref_node *node = NULL;
1177 struct backref_node *new_node;
1178 struct backref_edge *edge;
1179 struct backref_edge *new_edge;
1180 struct rb_node *rb_node;
1181
1182 if (cache->last_trans > 0)
1183 update_backref_cache(trans, cache);
1184
1185 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1186 if (rb_node) {
1187 node = rb_entry(rb_node, struct backref_node, rb_node);
1188 if (node->detached)
1189 node = NULL;
1190 else
1191 BUG_ON(node->new_bytenr != reloc_root->node->start);
1192 }
1193
1194 if (!node) {
1195 rb_node = tree_search(&cache->rb_root,
1196 reloc_root->commit_root->start);
1197 if (rb_node) {
1198 node = rb_entry(rb_node, struct backref_node,
1199 rb_node);
1200 BUG_ON(node->detached);
1201 }
1202 }
1203
1204 if (!node)
1205 return 0;
1206
1207 new_node = alloc_backref_node(cache);
1208 if (!new_node)
1209 return -ENOMEM;
1210
1211 new_node->bytenr = dest->node->start;
1212 new_node->level = node->level;
1213 new_node->lowest = node->lowest;
1214 new_node->checked = 1;
1215 new_node->root = dest;
1216
1217 if (!node->lowest) {
1218 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1219 new_edge = alloc_backref_edge(cache);
1220 if (!new_edge)
1221 goto fail;
1222
1223 new_edge->node[UPPER] = new_node;
1224 new_edge->node[LOWER] = edge->node[LOWER];
1225 list_add_tail(&new_edge->list[UPPER],
1226 &new_node->lower);
1227 }
1228 } else {
1229 list_add_tail(&new_node->lower, &cache->leaves);
1230 }
1231
1232 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1233 &new_node->rb_node);
1234 if (rb_node)
1235 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1236
1237 if (!new_node->lowest) {
1238 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1239 list_add_tail(&new_edge->list[LOWER],
1240 &new_edge->node[LOWER]->upper);
1241 }
1242 }
1243 return 0;
1244fail:
1245 while (!list_empty(&new_node->lower)) {
1246 new_edge = list_entry(new_node->lower.next,
1247 struct backref_edge, list[UPPER]);
1248 list_del(&new_edge->list[UPPER]);
1249 free_backref_edge(cache, new_edge);
1250 }
1251 free_backref_node(cache, new_node);
1252 return -ENOMEM;
1253}
1254
1255/*
1256 * helper to add 'address of tree root -> reloc tree' mapping
1257 */
1258static int __must_check __add_reloc_root(struct btrfs_root *root)
1259{
1260 struct btrfs_fs_info *fs_info = root->fs_info;
1261 struct rb_node *rb_node;
1262 struct mapping_node *node;
1263 struct reloc_control *rc = fs_info->reloc_ctl;
1264
1265 node = kmalloc(sizeof(*node), GFP_NOFS);
1266 if (!node)
1267 return -ENOMEM;
1268
1269 node->bytenr = root->node->start;
1270 node->data = root;
1271
1272 spin_lock(&rc->reloc_root_tree.lock);
1273 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1274 node->bytenr, &node->rb_node);
1275 spin_unlock(&rc->reloc_root_tree.lock);
1276 if (rb_node) {
1277 btrfs_panic(fs_info, -EEXIST,
1278 "Duplicate root found for start=%llu while inserting into relocation tree",
1279 node->bytenr);
1280 }
1281
1282 list_add_tail(&root->root_list, &rc->reloc_roots);
1283 return 0;
1284}
1285
1286/*
1287 * helper to delete the 'address of tree root -> reloc tree'
1288 * mapping
1289 */
1290static void __del_reloc_root(struct btrfs_root *root)
1291{
1292 struct btrfs_fs_info *fs_info = root->fs_info;
1293 struct rb_node *rb_node;
1294 struct mapping_node *node = NULL;
1295 struct reloc_control *rc = fs_info->reloc_ctl;
1296
1297 if (rc && root->node) {
1298 spin_lock(&rc->reloc_root_tree.lock);
1299 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1300 root->node->start);
1301 if (rb_node) {
1302 node = rb_entry(rb_node, struct mapping_node, rb_node);
1303 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1304 }
1305 spin_unlock(&rc->reloc_root_tree.lock);
1306 if (!node)
1307 return;
1308 BUG_ON((struct btrfs_root *)node->data != root);
1309 }
1310
1311 spin_lock(&fs_info->trans_lock);
1312 list_del_init(&root->root_list);
1313 spin_unlock(&fs_info->trans_lock);
1314 kfree(node);
1315}
1316
1317/*
1318 * helper to update the 'address of tree root -> reloc tree'
1319 * mapping
1320 */
1321static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1322{
1323 struct btrfs_fs_info *fs_info = root->fs_info;
1324 struct rb_node *rb_node;
1325 struct mapping_node *node = NULL;
1326 struct reloc_control *rc = fs_info->reloc_ctl;
1327
1328 spin_lock(&rc->reloc_root_tree.lock);
1329 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1330 root->node->start);
1331 if (rb_node) {
1332 node = rb_entry(rb_node, struct mapping_node, rb_node);
1333 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1334 }
1335 spin_unlock(&rc->reloc_root_tree.lock);
1336
1337 if (!node)
1338 return 0;
1339 BUG_ON((struct btrfs_root *)node->data != root);
1340
1341 spin_lock(&rc->reloc_root_tree.lock);
1342 node->bytenr = new_bytenr;
1343 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1344 node->bytenr, &node->rb_node);
1345 spin_unlock(&rc->reloc_root_tree.lock);
1346 if (rb_node)
1347 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1348 return 0;
1349}
1350
1351static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1352 struct btrfs_root *root, u64 objectid)
1353{
1354 struct btrfs_fs_info *fs_info = root->fs_info;
1355 struct btrfs_root *reloc_root;
1356 struct extent_buffer *eb;
1357 struct btrfs_root_item *root_item;
1358 struct btrfs_key root_key;
1359 int ret;
1360
1361 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1362 BUG_ON(!root_item);
1363
1364 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1365 root_key.type = BTRFS_ROOT_ITEM_KEY;
1366 root_key.offset = objectid;
1367
1368 if (root->root_key.objectid == objectid) {
1369 u64 commit_root_gen;
1370
1371 /* called by btrfs_init_reloc_root */
1372 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1373 BTRFS_TREE_RELOC_OBJECTID);
1374 BUG_ON(ret);
1375 /*
1376 * Set the last_snapshot field to the generation of the commit
1377 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1378 * correctly (returns true) when the relocation root is created
1379 * either inside the critical section of a transaction commit
1380 * (through transaction.c:qgroup_account_snapshot()) and when
1381 * it's created before the transaction commit is started.
1382 */
1383 commit_root_gen = btrfs_header_generation(root->commit_root);
1384 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1385 } else {
1386 /*
1387 * called by btrfs_reloc_post_snapshot_hook.
1388 * the source tree is a reloc tree, all tree blocks
1389 * modified after it was created have RELOC flag
1390 * set in their headers. so it's OK to not update
1391 * the 'last_snapshot'.
1392 */
1393 ret = btrfs_copy_root(trans, root, root->node, &eb,
1394 BTRFS_TREE_RELOC_OBJECTID);
1395 BUG_ON(ret);
1396 }
1397
1398 memcpy(root_item, &root->root_item, sizeof(*root_item));
1399 btrfs_set_root_bytenr(root_item, eb->start);
1400 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1401 btrfs_set_root_generation(root_item, trans->transid);
1402
1403 if (root->root_key.objectid == objectid) {
1404 btrfs_set_root_refs(root_item, 0);
1405 memset(&root_item->drop_progress, 0,
1406 sizeof(struct btrfs_disk_key));
1407 root_item->drop_level = 0;
1408 }
1409
1410 btrfs_tree_unlock(eb);
1411 free_extent_buffer(eb);
1412
1413 ret = btrfs_insert_root(trans, fs_info->tree_root,
1414 &root_key, root_item);
1415 BUG_ON(ret);
1416 kfree(root_item);
1417
1418 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1419 BUG_ON(IS_ERR(reloc_root));
1420 reloc_root->last_trans = trans->transid;
1421 return reloc_root;
1422}
1423
1424/*
1425 * create reloc tree for a given fs tree. reloc tree is just a
1426 * snapshot of the fs tree with special root objectid.
1427 */
1428int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1429 struct btrfs_root *root)
1430{
1431 struct btrfs_fs_info *fs_info = root->fs_info;
1432 struct btrfs_root *reloc_root;
1433 struct reloc_control *rc = fs_info->reloc_ctl;
1434 struct btrfs_block_rsv *rsv;
1435 int clear_rsv = 0;
1436 int ret;
1437
1438 /*
1439 * The subvolume has reloc tree but the swap is finished, no need to
1440 * create/update the dead reloc tree
1441 */
1442 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
1443 return 0;
1444
1445 if (root->reloc_root) {
1446 reloc_root = root->reloc_root;
1447 reloc_root->last_trans = trans->transid;
1448 return 0;
1449 }
1450
1451 if (!rc || !rc->create_reloc_tree ||
1452 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1453 return 0;
1454
1455 if (!trans->reloc_reserved) {
1456 rsv = trans->block_rsv;
1457 trans->block_rsv = rc->block_rsv;
1458 clear_rsv = 1;
1459 }
1460 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1461 if (clear_rsv)
1462 trans->block_rsv = rsv;
1463
1464 ret = __add_reloc_root(reloc_root);
1465 BUG_ON(ret < 0);
1466 root->reloc_root = reloc_root;
1467 return 0;
1468}
1469
1470/*
1471 * update root item of reloc tree
1472 */
1473int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1474 struct btrfs_root *root)
1475{
1476 struct btrfs_fs_info *fs_info = root->fs_info;
1477 struct btrfs_root *reloc_root;
1478 struct btrfs_root_item *root_item;
1479 int ret;
1480
1481 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1482 !root->reloc_root)
1483 goto out;
1484
1485 reloc_root = root->reloc_root;
1486 root_item = &reloc_root->root_item;
1487
1488 /* root->reloc_root will stay until current relocation finished */
1489 if (fs_info->reloc_ctl->merge_reloc_tree &&
1490 btrfs_root_refs(root_item) == 0) {
1491 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1492 __del_reloc_root(reloc_root);
1493 }
1494
1495 if (reloc_root->commit_root != reloc_root->node) {
1496 btrfs_set_root_node(root_item, reloc_root->node);
1497 free_extent_buffer(reloc_root->commit_root);
1498 reloc_root->commit_root = btrfs_root_node(reloc_root);
1499 }
1500
1501 ret = btrfs_update_root(trans, fs_info->tree_root,
1502 &reloc_root->root_key, root_item);
1503 BUG_ON(ret);
1504
1505out:
1506 return 0;
1507}
1508
1509/*
1510 * helper to find first cached inode with inode number >= objectid
1511 * in a subvolume
1512 */
1513static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1514{
1515 struct rb_node *node;
1516 struct rb_node *prev;
1517 struct btrfs_inode *entry;
1518 struct inode *inode;
1519
1520 spin_lock(&root->inode_lock);
1521again:
1522 node = root->inode_tree.rb_node;
1523 prev = NULL;
1524 while (node) {
1525 prev = node;
1526 entry = rb_entry(node, struct btrfs_inode, rb_node);
1527
1528 if (objectid < btrfs_ino(entry))
1529 node = node->rb_left;
1530 else if (objectid > btrfs_ino(entry))
1531 node = node->rb_right;
1532 else
1533 break;
1534 }
1535 if (!node) {
1536 while (prev) {
1537 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1538 if (objectid <= btrfs_ino(entry)) {
1539 node = prev;
1540 break;
1541 }
1542 prev = rb_next(prev);
1543 }
1544 }
1545 while (node) {
1546 entry = rb_entry(node, struct btrfs_inode, rb_node);
1547 inode = igrab(&entry->vfs_inode);
1548 if (inode) {
1549 spin_unlock(&root->inode_lock);
1550 return inode;
1551 }
1552
1553 objectid = btrfs_ino(entry) + 1;
1554 if (cond_resched_lock(&root->inode_lock))
1555 goto again;
1556
1557 node = rb_next(node);
1558 }
1559 spin_unlock(&root->inode_lock);
1560 return NULL;
1561}
1562
1563static int in_block_group(u64 bytenr,
1564 struct btrfs_block_group_cache *block_group)
1565{
1566 if (bytenr >= block_group->key.objectid &&
1567 bytenr < block_group->key.objectid + block_group->key.offset)
1568 return 1;
1569 return 0;
1570}
1571
1572/*
1573 * get new location of data
1574 */
1575static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1576 u64 bytenr, u64 num_bytes)
1577{
1578 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1579 struct btrfs_path *path;
1580 struct btrfs_file_extent_item *fi;
1581 struct extent_buffer *leaf;
1582 int ret;
1583
1584 path = btrfs_alloc_path();
1585 if (!path)
1586 return -ENOMEM;
1587
1588 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1589 ret = btrfs_lookup_file_extent(NULL, root, path,
1590 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1591 if (ret < 0)
1592 goto out;
1593 if (ret > 0) {
1594 ret = -ENOENT;
1595 goto out;
1596 }
1597
1598 leaf = path->nodes[0];
1599 fi = btrfs_item_ptr(leaf, path->slots[0],
1600 struct btrfs_file_extent_item);
1601
1602 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1603 btrfs_file_extent_compression(leaf, fi) ||
1604 btrfs_file_extent_encryption(leaf, fi) ||
1605 btrfs_file_extent_other_encoding(leaf, fi));
1606
1607 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1608 ret = -EINVAL;
1609 goto out;
1610 }
1611
1612 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1613 ret = 0;
1614out:
1615 btrfs_free_path(path);
1616 return ret;
1617}
1618
1619/*
1620 * update file extent items in the tree leaf to point to
1621 * the new locations.
1622 */
1623static noinline_for_stack
1624int replace_file_extents(struct btrfs_trans_handle *trans,
1625 struct reloc_control *rc,
1626 struct btrfs_root *root,
1627 struct extent_buffer *leaf)
1628{
1629 struct btrfs_fs_info *fs_info = root->fs_info;
1630 struct btrfs_key key;
1631 struct btrfs_file_extent_item *fi;
1632 struct inode *inode = NULL;
1633 u64 parent;
1634 u64 bytenr;
1635 u64 new_bytenr = 0;
1636 u64 num_bytes;
1637 u64 end;
1638 u32 nritems;
1639 u32 i;
1640 int ret = 0;
1641 int first = 1;
1642 int dirty = 0;
1643
1644 if (rc->stage != UPDATE_DATA_PTRS)
1645 return 0;
1646
1647 /* reloc trees always use full backref */
1648 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1649 parent = leaf->start;
1650 else
1651 parent = 0;
1652
1653 nritems = btrfs_header_nritems(leaf);
1654 for (i = 0; i < nritems; i++) {
1655 struct btrfs_ref ref = { 0 };
1656
1657 cond_resched();
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
1660 continue;
1661 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1662 if (btrfs_file_extent_type(leaf, fi) ==
1663 BTRFS_FILE_EXTENT_INLINE)
1664 continue;
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1667 if (bytenr == 0)
1668 continue;
1669 if (!in_block_group(bytenr, rc->block_group))
1670 continue;
1671
1672 /*
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1675 */
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1677 if (first) {
1678 inode = find_next_inode(root, key.objectid);
1679 first = 0;
1680 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1681 btrfs_add_delayed_iput(inode);
1682 inode = find_next_inode(root, key.objectid);
1683 }
1684 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1685 end = key.offset +
1686 btrfs_file_extent_num_bytes(leaf, fi);
1687 WARN_ON(!IS_ALIGNED(key.offset,
1688 fs_info->sectorsize));
1689 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1690 end--;
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1692 key.offset, end);
1693 if (!ret)
1694 continue;
1695
1696 btrfs_drop_extent_cache(BTRFS_I(inode),
1697 key.offset, end, 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1699 key.offset, end);
1700 }
1701 }
1702
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1704 bytenr, num_bytes);
1705 if (ret) {
1706 /*
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1709 */
1710 break;
1711 }
1712
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1714 dirty = 1;
1715
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1718 num_bytes, parent);
1719 ref.real_root = root->root_key.objectid;
1720 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1721 key.objectid, key.offset);
1722 ret = btrfs_inc_extent_ref(trans, &ref);
1723 if (ret) {
1724 btrfs_abort_transaction(trans, ret);
1725 break;
1726 }
1727
1728 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1729 num_bytes, parent);
1730 ref.real_root = root->root_key.objectid;
1731 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1732 key.objectid, key.offset);
1733 ret = btrfs_free_extent(trans, &ref);
1734 if (ret) {
1735 btrfs_abort_transaction(trans, ret);
1736 break;
1737 }
1738 }
1739 if (dirty)
1740 btrfs_mark_buffer_dirty(leaf);
1741 if (inode)
1742 btrfs_add_delayed_iput(inode);
1743 return ret;
1744}
1745
1746static noinline_for_stack
1747int memcmp_node_keys(struct extent_buffer *eb, int slot,
1748 struct btrfs_path *path, int level)
1749{
1750 struct btrfs_disk_key key1;
1751 struct btrfs_disk_key key2;
1752 btrfs_node_key(eb, &key1, slot);
1753 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1754 return memcmp(&key1, &key2, sizeof(key1));
1755}
1756
1757/*
1758 * try to replace tree blocks in fs tree with the new blocks
1759 * in reloc tree. tree blocks haven't been modified since the
1760 * reloc tree was create can be replaced.
1761 *
1762 * if a block was replaced, level of the block + 1 is returned.
1763 * if no block got replaced, 0 is returned. if there are other
1764 * errors, a negative error number is returned.
1765 */
1766static noinline_for_stack
1767int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1768 struct btrfs_root *dest, struct btrfs_root *src,
1769 struct btrfs_path *path, struct btrfs_key *next_key,
1770 int lowest_level, int max_level)
1771{
1772 struct btrfs_fs_info *fs_info = dest->fs_info;
1773 struct extent_buffer *eb;
1774 struct extent_buffer *parent;
1775 struct btrfs_ref ref = { 0 };
1776 struct btrfs_key key;
1777 u64 old_bytenr;
1778 u64 new_bytenr;
1779 u64 old_ptr_gen;
1780 u64 new_ptr_gen;
1781 u64 last_snapshot;
1782 u32 blocksize;
1783 int cow = 0;
1784 int level;
1785 int ret;
1786 int slot;
1787
1788 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1789 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1790
1791 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1792again:
1793 slot = path->slots[lowest_level];
1794 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1795
1796 eb = btrfs_lock_root_node(dest);
1797 btrfs_set_lock_blocking_write(eb);
1798 level = btrfs_header_level(eb);
1799
1800 if (level < lowest_level) {
1801 btrfs_tree_unlock(eb);
1802 free_extent_buffer(eb);
1803 return 0;
1804 }
1805
1806 if (cow) {
1807 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1808 BUG_ON(ret);
1809 }
1810 btrfs_set_lock_blocking_write(eb);
1811
1812 if (next_key) {
1813 next_key->objectid = (u64)-1;
1814 next_key->type = (u8)-1;
1815 next_key->offset = (u64)-1;
1816 }
1817
1818 parent = eb;
1819 while (1) {
1820 struct btrfs_key first_key;
1821
1822 level = btrfs_header_level(parent);
1823 BUG_ON(level < lowest_level);
1824
1825 ret = btrfs_bin_search(parent, &key, level, &slot);
1826 if (ret < 0)
1827 break;
1828 if (ret && slot > 0)
1829 slot--;
1830
1831 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1832 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1833
1834 old_bytenr = btrfs_node_blockptr(parent, slot);
1835 blocksize = fs_info->nodesize;
1836 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1837 btrfs_node_key_to_cpu(parent, &first_key, slot);
1838
1839 if (level <= max_level) {
1840 eb = path->nodes[level];
1841 new_bytenr = btrfs_node_blockptr(eb,
1842 path->slots[level]);
1843 new_ptr_gen = btrfs_node_ptr_generation(eb,
1844 path->slots[level]);
1845 } else {
1846 new_bytenr = 0;
1847 new_ptr_gen = 0;
1848 }
1849
1850 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1851 ret = level;
1852 break;
1853 }
1854
1855 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1856 memcmp_node_keys(parent, slot, path, level)) {
1857 if (level <= lowest_level) {
1858 ret = 0;
1859 break;
1860 }
1861
1862 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1863 level - 1, &first_key);
1864 if (IS_ERR(eb)) {
1865 ret = PTR_ERR(eb);
1866 break;
1867 } else if (!extent_buffer_uptodate(eb)) {
1868 ret = -EIO;
1869 free_extent_buffer(eb);
1870 break;
1871 }
1872 btrfs_tree_lock(eb);
1873 if (cow) {
1874 ret = btrfs_cow_block(trans, dest, eb, parent,
1875 slot, &eb);
1876 BUG_ON(ret);
1877 }
1878 btrfs_set_lock_blocking_write(eb);
1879
1880 btrfs_tree_unlock(parent);
1881 free_extent_buffer(parent);
1882
1883 parent = eb;
1884 continue;
1885 }
1886
1887 if (!cow) {
1888 btrfs_tree_unlock(parent);
1889 free_extent_buffer(parent);
1890 cow = 1;
1891 goto again;
1892 }
1893
1894 btrfs_node_key_to_cpu(path->nodes[level], &key,
1895 path->slots[level]);
1896 btrfs_release_path(path);
1897
1898 path->lowest_level = level;
1899 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1900 path->lowest_level = 0;
1901 BUG_ON(ret);
1902
1903 /*
1904 * Info qgroup to trace both subtrees.
1905 *
1906 * We must trace both trees.
1907 * 1) Tree reloc subtree
1908 * If not traced, we will leak data numbers
1909 * 2) Fs subtree
1910 * If not traced, we will double count old data
1911 *
1912 * We don't scan the subtree right now, but only record
1913 * the swapped tree blocks.
1914 * The real subtree rescan is delayed until we have new
1915 * CoW on the subtree root node before transaction commit.
1916 */
1917 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1918 rc->block_group, parent, slot,
1919 path->nodes[level], path->slots[level],
1920 last_snapshot);
1921 if (ret < 0)
1922 break;
1923 /*
1924 * swap blocks in fs tree and reloc tree.
1925 */
1926 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1927 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1928 btrfs_mark_buffer_dirty(parent);
1929
1930 btrfs_set_node_blockptr(path->nodes[level],
1931 path->slots[level], old_bytenr);
1932 btrfs_set_node_ptr_generation(path->nodes[level],
1933 path->slots[level], old_ptr_gen);
1934 btrfs_mark_buffer_dirty(path->nodes[level]);
1935
1936 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1937 blocksize, path->nodes[level]->start);
1938 ref.skip_qgroup = true;
1939 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1940 ret = btrfs_inc_extent_ref(trans, &ref);
1941 BUG_ON(ret);
1942 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1943 blocksize, 0);
1944 ref.skip_qgroup = true;
1945 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1946 ret = btrfs_inc_extent_ref(trans, &ref);
1947 BUG_ON(ret);
1948
1949 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1950 blocksize, path->nodes[level]->start);
1951 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1952 ref.skip_qgroup = true;
1953 ret = btrfs_free_extent(trans, &ref);
1954 BUG_ON(ret);
1955
1956 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1957 blocksize, 0);
1958 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1959 ref.skip_qgroup = true;
1960 ret = btrfs_free_extent(trans, &ref);
1961 BUG_ON(ret);
1962
1963 btrfs_unlock_up_safe(path, 0);
1964
1965 ret = level;
1966 break;
1967 }
1968 btrfs_tree_unlock(parent);
1969 free_extent_buffer(parent);
1970 return ret;
1971}
1972
1973/*
1974 * helper to find next relocated block in reloc tree
1975 */
1976static noinline_for_stack
1977int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1978 int *level)
1979{
1980 struct extent_buffer *eb;
1981 int i;
1982 u64 last_snapshot;
1983 u32 nritems;
1984
1985 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1986
1987 for (i = 0; i < *level; i++) {
1988 free_extent_buffer(path->nodes[i]);
1989 path->nodes[i] = NULL;
1990 }
1991
1992 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1993 eb = path->nodes[i];
1994 nritems = btrfs_header_nritems(eb);
1995 while (path->slots[i] + 1 < nritems) {
1996 path->slots[i]++;
1997 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1998 last_snapshot)
1999 continue;
2000
2001 *level = i;
2002 return 0;
2003 }
2004 free_extent_buffer(path->nodes[i]);
2005 path->nodes[i] = NULL;
2006 }
2007 return 1;
2008}
2009
2010/*
2011 * walk down reloc tree to find relocated block of lowest level
2012 */
2013static noinline_for_stack
2014int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2015 int *level)
2016{
2017 struct btrfs_fs_info *fs_info = root->fs_info;
2018 struct extent_buffer *eb = NULL;
2019 int i;
2020 u64 bytenr;
2021 u64 ptr_gen = 0;
2022 u64 last_snapshot;
2023 u32 nritems;
2024
2025 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2026
2027 for (i = *level; i > 0; i--) {
2028 struct btrfs_key first_key;
2029
2030 eb = path->nodes[i];
2031 nritems = btrfs_header_nritems(eb);
2032 while (path->slots[i] < nritems) {
2033 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2034 if (ptr_gen > last_snapshot)
2035 break;
2036 path->slots[i]++;
2037 }
2038 if (path->slots[i] >= nritems) {
2039 if (i == *level)
2040 break;
2041 *level = i + 1;
2042 return 0;
2043 }
2044 if (i == 1) {
2045 *level = i;
2046 return 0;
2047 }
2048
2049 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2050 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2051 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2052 &first_key);
2053 if (IS_ERR(eb)) {
2054 return PTR_ERR(eb);
2055 } else if (!extent_buffer_uptodate(eb)) {
2056 free_extent_buffer(eb);
2057 return -EIO;
2058 }
2059 BUG_ON(btrfs_header_level(eb) != i - 1);
2060 path->nodes[i - 1] = eb;
2061 path->slots[i - 1] = 0;
2062 }
2063 return 1;
2064}
2065
2066/*
2067 * invalidate extent cache for file extents whose key in range of
2068 * [min_key, max_key)
2069 */
2070static int invalidate_extent_cache(struct btrfs_root *root,
2071 struct btrfs_key *min_key,
2072 struct btrfs_key *max_key)
2073{
2074 struct btrfs_fs_info *fs_info = root->fs_info;
2075 struct inode *inode = NULL;
2076 u64 objectid;
2077 u64 start, end;
2078 u64 ino;
2079
2080 objectid = min_key->objectid;
2081 while (1) {
2082 cond_resched();
2083 iput(inode);
2084
2085 if (objectid > max_key->objectid)
2086 break;
2087
2088 inode = find_next_inode(root, objectid);
2089 if (!inode)
2090 break;
2091 ino = btrfs_ino(BTRFS_I(inode));
2092
2093 if (ino > max_key->objectid) {
2094 iput(inode);
2095 break;
2096 }
2097
2098 objectid = ino + 1;
2099 if (!S_ISREG(inode->i_mode))
2100 continue;
2101
2102 if (unlikely(min_key->objectid == ino)) {
2103 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2104 continue;
2105 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2106 start = 0;
2107 else {
2108 start = min_key->offset;
2109 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2110 }
2111 } else {
2112 start = 0;
2113 }
2114
2115 if (unlikely(max_key->objectid == ino)) {
2116 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2117 continue;
2118 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2119 end = (u64)-1;
2120 } else {
2121 if (max_key->offset == 0)
2122 continue;
2123 end = max_key->offset;
2124 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2125 end--;
2126 }
2127 } else {
2128 end = (u64)-1;
2129 }
2130
2131 /* the lock_extent waits for readpage to complete */
2132 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2133 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2134 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2135 }
2136 return 0;
2137}
2138
2139static int find_next_key(struct btrfs_path *path, int level,
2140 struct btrfs_key *key)
2141
2142{
2143 while (level < BTRFS_MAX_LEVEL) {
2144 if (!path->nodes[level])
2145 break;
2146 if (path->slots[level] + 1 <
2147 btrfs_header_nritems(path->nodes[level])) {
2148 btrfs_node_key_to_cpu(path->nodes[level], key,
2149 path->slots[level] + 1);
2150 return 0;
2151 }
2152 level++;
2153 }
2154 return 1;
2155}
2156
2157/*
2158 * Insert current subvolume into reloc_control::dirty_subvol_roots
2159 */
2160static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2161 struct reloc_control *rc,
2162 struct btrfs_root *root)
2163{
2164 struct btrfs_root *reloc_root = root->reloc_root;
2165 struct btrfs_root_item *reloc_root_item;
2166
2167 /* @root must be a subvolume tree root with a valid reloc tree */
2168 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2169 ASSERT(reloc_root);
2170
2171 reloc_root_item = &reloc_root->root_item;
2172 memset(&reloc_root_item->drop_progress, 0,
2173 sizeof(reloc_root_item->drop_progress));
2174 reloc_root_item->drop_level = 0;
2175 btrfs_set_root_refs(reloc_root_item, 0);
2176 btrfs_update_reloc_root(trans, root);
2177
2178 if (list_empty(&root->reloc_dirty_list)) {
2179 btrfs_grab_fs_root(root);
2180 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2181 }
2182}
2183
2184static int clean_dirty_subvols(struct reloc_control *rc)
2185{
2186 struct btrfs_root *root;
2187 struct btrfs_root *next;
2188 int ret = 0;
2189 int ret2;
2190
2191 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2192 reloc_dirty_list) {
2193 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2194 /* Merged subvolume, cleanup its reloc root */
2195 struct btrfs_root *reloc_root = root->reloc_root;
2196
2197 list_del_init(&root->reloc_dirty_list);
2198 root->reloc_root = NULL;
2199 if (reloc_root) {
2200
2201 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2202 if (ret2 < 0 && !ret)
2203 ret = ret2;
2204 }
2205 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2206 btrfs_put_fs_root(root);
2207 } else {
2208 /* Orphan reloc tree, just clean it up */
2209 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2210 if (ret2 < 0 && !ret)
2211 ret = ret2;
2212 }
2213 }
2214 return ret;
2215}
2216
2217/*
2218 * merge the relocated tree blocks in reloc tree with corresponding
2219 * fs tree.
2220 */
2221static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2222 struct btrfs_root *root)
2223{
2224 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2225 struct btrfs_key key;
2226 struct btrfs_key next_key;
2227 struct btrfs_trans_handle *trans = NULL;
2228 struct btrfs_root *reloc_root;
2229 struct btrfs_root_item *root_item;
2230 struct btrfs_path *path;
2231 struct extent_buffer *leaf;
2232 int level;
2233 int max_level;
2234 int replaced = 0;
2235 int ret;
2236 int err = 0;
2237 u32 min_reserved;
2238
2239 path = btrfs_alloc_path();
2240 if (!path)
2241 return -ENOMEM;
2242 path->reada = READA_FORWARD;
2243
2244 reloc_root = root->reloc_root;
2245 root_item = &reloc_root->root_item;
2246
2247 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2248 level = btrfs_root_level(root_item);
2249 extent_buffer_get(reloc_root->node);
2250 path->nodes[level] = reloc_root->node;
2251 path->slots[level] = 0;
2252 } else {
2253 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2254
2255 level = root_item->drop_level;
2256 BUG_ON(level == 0);
2257 path->lowest_level = level;
2258 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2259 path->lowest_level = 0;
2260 if (ret < 0) {
2261 btrfs_free_path(path);
2262 return ret;
2263 }
2264
2265 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2266 path->slots[level]);
2267 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2268
2269 btrfs_unlock_up_safe(path, 0);
2270 }
2271
2272 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2273 memset(&next_key, 0, sizeof(next_key));
2274
2275 while (1) {
2276 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2277 BTRFS_RESERVE_FLUSH_ALL);
2278 if (ret) {
2279 err = ret;
2280 goto out;
2281 }
2282 trans = btrfs_start_transaction(root, 0);
2283 if (IS_ERR(trans)) {
2284 err = PTR_ERR(trans);
2285 trans = NULL;
2286 goto out;
2287 }
2288 trans->block_rsv = rc->block_rsv;
2289
2290 replaced = 0;
2291 max_level = level;
2292
2293 ret = walk_down_reloc_tree(reloc_root, path, &level);
2294 if (ret < 0) {
2295 err = ret;
2296 goto out;
2297 }
2298 if (ret > 0)
2299 break;
2300
2301 if (!find_next_key(path, level, &key) &&
2302 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2303 ret = 0;
2304 } else {
2305 ret = replace_path(trans, rc, root, reloc_root, path,
2306 &next_key, level, max_level);
2307 }
2308 if (ret < 0) {
2309 err = ret;
2310 goto out;
2311 }
2312
2313 if (ret > 0) {
2314 level = ret;
2315 btrfs_node_key_to_cpu(path->nodes[level], &key,
2316 path->slots[level]);
2317 replaced = 1;
2318 }
2319
2320 ret = walk_up_reloc_tree(reloc_root, path, &level);
2321 if (ret > 0)
2322 break;
2323
2324 BUG_ON(level == 0);
2325 /*
2326 * save the merging progress in the drop_progress.
2327 * this is OK since root refs == 1 in this case.
2328 */
2329 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2330 path->slots[level]);
2331 root_item->drop_level = level;
2332
2333 btrfs_end_transaction_throttle(trans);
2334 trans = NULL;
2335
2336 btrfs_btree_balance_dirty(fs_info);
2337
2338 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2339 invalidate_extent_cache(root, &key, &next_key);
2340 }
2341
2342 /*
2343 * handle the case only one block in the fs tree need to be
2344 * relocated and the block is tree root.
2345 */
2346 leaf = btrfs_lock_root_node(root);
2347 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2348 btrfs_tree_unlock(leaf);
2349 free_extent_buffer(leaf);
2350 if (ret < 0)
2351 err = ret;
2352out:
2353 btrfs_free_path(path);
2354
2355 if (err == 0)
2356 insert_dirty_subvol(trans, rc, root);
2357
2358 if (trans)
2359 btrfs_end_transaction_throttle(trans);
2360
2361 btrfs_btree_balance_dirty(fs_info);
2362
2363 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2364 invalidate_extent_cache(root, &key, &next_key);
2365
2366 return err;
2367}
2368
2369static noinline_for_stack
2370int prepare_to_merge(struct reloc_control *rc, int err)
2371{
2372 struct btrfs_root *root = rc->extent_root;
2373 struct btrfs_fs_info *fs_info = root->fs_info;
2374 struct btrfs_root *reloc_root;
2375 struct btrfs_trans_handle *trans;
2376 LIST_HEAD(reloc_roots);
2377 u64 num_bytes = 0;
2378 int ret;
2379
2380 mutex_lock(&fs_info->reloc_mutex);
2381 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2382 rc->merging_rsv_size += rc->nodes_relocated * 2;
2383 mutex_unlock(&fs_info->reloc_mutex);
2384
2385again:
2386 if (!err) {
2387 num_bytes = rc->merging_rsv_size;
2388 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2389 BTRFS_RESERVE_FLUSH_ALL);
2390 if (ret)
2391 err = ret;
2392 }
2393
2394 trans = btrfs_join_transaction(rc->extent_root);
2395 if (IS_ERR(trans)) {
2396 if (!err)
2397 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2398 num_bytes);
2399 return PTR_ERR(trans);
2400 }
2401
2402 if (!err) {
2403 if (num_bytes != rc->merging_rsv_size) {
2404 btrfs_end_transaction(trans);
2405 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2406 num_bytes);
2407 goto again;
2408 }
2409 }
2410
2411 rc->merge_reloc_tree = 1;
2412
2413 while (!list_empty(&rc->reloc_roots)) {
2414 reloc_root = list_entry(rc->reloc_roots.next,
2415 struct btrfs_root, root_list);
2416 list_del_init(&reloc_root->root_list);
2417
2418 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2419 BUG_ON(IS_ERR(root));
2420 BUG_ON(root->reloc_root != reloc_root);
2421
2422 /*
2423 * set reference count to 1, so btrfs_recover_relocation
2424 * knows it should resumes merging
2425 */
2426 if (!err)
2427 btrfs_set_root_refs(&reloc_root->root_item, 1);
2428 btrfs_update_reloc_root(trans, root);
2429
2430 list_add(&reloc_root->root_list, &reloc_roots);
2431 }
2432
2433 list_splice(&reloc_roots, &rc->reloc_roots);
2434
2435 if (!err)
2436 btrfs_commit_transaction(trans);
2437 else
2438 btrfs_end_transaction(trans);
2439 return err;
2440}
2441
2442static noinline_for_stack
2443void free_reloc_roots(struct list_head *list)
2444{
2445 struct btrfs_root *reloc_root;
2446
2447 while (!list_empty(list)) {
2448 reloc_root = list_entry(list->next, struct btrfs_root,
2449 root_list);
2450 __del_reloc_root(reloc_root);
2451 free_extent_buffer(reloc_root->node);
2452 free_extent_buffer(reloc_root->commit_root);
2453 reloc_root->node = NULL;
2454 reloc_root->commit_root = NULL;
2455 }
2456}
2457
2458static noinline_for_stack
2459void merge_reloc_roots(struct reloc_control *rc)
2460{
2461 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2462 struct btrfs_root *root;
2463 struct btrfs_root *reloc_root;
2464 LIST_HEAD(reloc_roots);
2465 int found = 0;
2466 int ret = 0;
2467again:
2468 root = rc->extent_root;
2469
2470 /*
2471 * this serializes us with btrfs_record_root_in_transaction,
2472 * we have to make sure nobody is in the middle of
2473 * adding their roots to the list while we are
2474 * doing this splice
2475 */
2476 mutex_lock(&fs_info->reloc_mutex);
2477 list_splice_init(&rc->reloc_roots, &reloc_roots);
2478 mutex_unlock(&fs_info->reloc_mutex);
2479
2480 while (!list_empty(&reloc_roots)) {
2481 found = 1;
2482 reloc_root = list_entry(reloc_roots.next,
2483 struct btrfs_root, root_list);
2484
2485 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2486 root = read_fs_root(fs_info,
2487 reloc_root->root_key.offset);
2488 BUG_ON(IS_ERR(root));
2489 BUG_ON(root->reloc_root != reloc_root);
2490
2491 ret = merge_reloc_root(rc, root);
2492 if (ret) {
2493 if (list_empty(&reloc_root->root_list))
2494 list_add_tail(&reloc_root->root_list,
2495 &reloc_roots);
2496 goto out;
2497 }
2498 } else {
2499 list_del_init(&reloc_root->root_list);
2500 /* Don't forget to queue this reloc root for cleanup */
2501 list_add_tail(&reloc_root->reloc_dirty_list,
2502 &rc->dirty_subvol_roots);
2503 }
2504 }
2505
2506 if (found) {
2507 found = 0;
2508 goto again;
2509 }
2510out:
2511 if (ret) {
2512 btrfs_handle_fs_error(fs_info, ret, NULL);
2513 if (!list_empty(&reloc_roots))
2514 free_reloc_roots(&reloc_roots);
2515
2516 /* new reloc root may be added */
2517 mutex_lock(&fs_info->reloc_mutex);
2518 list_splice_init(&rc->reloc_roots, &reloc_roots);
2519 mutex_unlock(&fs_info->reloc_mutex);
2520 if (!list_empty(&reloc_roots))
2521 free_reloc_roots(&reloc_roots);
2522 }
2523
2524 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2525}
2526
2527static void free_block_list(struct rb_root *blocks)
2528{
2529 struct tree_block *block;
2530 struct rb_node *rb_node;
2531 while ((rb_node = rb_first(blocks))) {
2532 block = rb_entry(rb_node, struct tree_block, rb_node);
2533 rb_erase(rb_node, blocks);
2534 kfree(block);
2535 }
2536}
2537
2538static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2539 struct btrfs_root *reloc_root)
2540{
2541 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2542 struct btrfs_root *root;
2543
2544 if (reloc_root->last_trans == trans->transid)
2545 return 0;
2546
2547 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2548 BUG_ON(IS_ERR(root));
2549 BUG_ON(root->reloc_root != reloc_root);
2550
2551 return btrfs_record_root_in_trans(trans, root);
2552}
2553
2554static noinline_for_stack
2555struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2556 struct reloc_control *rc,
2557 struct backref_node *node,
2558 struct backref_edge *edges[])
2559{
2560 struct backref_node *next;
2561 struct btrfs_root *root;
2562 int index = 0;
2563
2564 next = node;
2565 while (1) {
2566 cond_resched();
2567 next = walk_up_backref(next, edges, &index);
2568 root = next->root;
2569 BUG_ON(!root);
2570 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2571
2572 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2573 record_reloc_root_in_trans(trans, root);
2574 break;
2575 }
2576
2577 btrfs_record_root_in_trans(trans, root);
2578 root = root->reloc_root;
2579
2580 if (next->new_bytenr != root->node->start) {
2581 BUG_ON(next->new_bytenr);
2582 BUG_ON(!list_empty(&next->list));
2583 next->new_bytenr = root->node->start;
2584 next->root = root;
2585 list_add_tail(&next->list,
2586 &rc->backref_cache.changed);
2587 __mark_block_processed(rc, next);
2588 break;
2589 }
2590
2591 WARN_ON(1);
2592 root = NULL;
2593 next = walk_down_backref(edges, &index);
2594 if (!next || next->level <= node->level)
2595 break;
2596 }
2597 if (!root)
2598 return NULL;
2599
2600 next = node;
2601 /* setup backref node path for btrfs_reloc_cow_block */
2602 while (1) {
2603 rc->backref_cache.path[next->level] = next;
2604 if (--index < 0)
2605 break;
2606 next = edges[index]->node[UPPER];
2607 }
2608 return root;
2609}
2610
2611/*
2612 * select a tree root for relocation. return NULL if the block
2613 * is reference counted. we should use do_relocation() in this
2614 * case. return a tree root pointer if the block isn't reference
2615 * counted. return -ENOENT if the block is root of reloc tree.
2616 */
2617static noinline_for_stack
2618struct btrfs_root *select_one_root(struct backref_node *node)
2619{
2620 struct backref_node *next;
2621 struct btrfs_root *root;
2622 struct btrfs_root *fs_root = NULL;
2623 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2624 int index = 0;
2625
2626 next = node;
2627 while (1) {
2628 cond_resched();
2629 next = walk_up_backref(next, edges, &index);
2630 root = next->root;
2631 BUG_ON(!root);
2632
2633 /* no other choice for non-references counted tree */
2634 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2635 return root;
2636
2637 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2638 fs_root = root;
2639
2640 if (next != node)
2641 return NULL;
2642
2643 next = walk_down_backref(edges, &index);
2644 if (!next || next->level <= node->level)
2645 break;
2646 }
2647
2648 if (!fs_root)
2649 return ERR_PTR(-ENOENT);
2650 return fs_root;
2651}
2652
2653static noinline_for_stack
2654u64 calcu_metadata_size(struct reloc_control *rc,
2655 struct backref_node *node, int reserve)
2656{
2657 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2658 struct backref_node *next = node;
2659 struct backref_edge *edge;
2660 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2661 u64 num_bytes = 0;
2662 int index = 0;
2663
2664 BUG_ON(reserve && node->processed);
2665
2666 while (next) {
2667 cond_resched();
2668 while (1) {
2669 if (next->processed && (reserve || next != node))
2670 break;
2671
2672 num_bytes += fs_info->nodesize;
2673
2674 if (list_empty(&next->upper))
2675 break;
2676
2677 edge = list_entry(next->upper.next,
2678 struct backref_edge, list[LOWER]);
2679 edges[index++] = edge;
2680 next = edge->node[UPPER];
2681 }
2682 next = walk_down_backref(edges, &index);
2683 }
2684 return num_bytes;
2685}
2686
2687static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2688 struct reloc_control *rc,
2689 struct backref_node *node)
2690{
2691 struct btrfs_root *root = rc->extent_root;
2692 struct btrfs_fs_info *fs_info = root->fs_info;
2693 u64 num_bytes;
2694 int ret;
2695 u64 tmp;
2696
2697 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2698
2699 trans->block_rsv = rc->block_rsv;
2700 rc->reserved_bytes += num_bytes;
2701
2702 /*
2703 * We are under a transaction here so we can only do limited flushing.
2704 * If we get an enospc just kick back -EAGAIN so we know to drop the
2705 * transaction and try to refill when we can flush all the things.
2706 */
2707 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2708 BTRFS_RESERVE_FLUSH_LIMIT);
2709 if (ret) {
2710 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2711 while (tmp <= rc->reserved_bytes)
2712 tmp <<= 1;
2713 /*
2714 * only one thread can access block_rsv at this point,
2715 * so we don't need hold lock to protect block_rsv.
2716 * we expand more reservation size here to allow enough
2717 * space for relocation and we will return earlier in
2718 * enospc case.
2719 */
2720 rc->block_rsv->size = tmp + fs_info->nodesize *
2721 RELOCATION_RESERVED_NODES;
2722 return -EAGAIN;
2723 }
2724
2725 return 0;
2726}
2727
2728/*
2729 * relocate a block tree, and then update pointers in upper level
2730 * blocks that reference the block to point to the new location.
2731 *
2732 * if called by link_to_upper, the block has already been relocated.
2733 * in that case this function just updates pointers.
2734 */
2735static int do_relocation(struct btrfs_trans_handle *trans,
2736 struct reloc_control *rc,
2737 struct backref_node *node,
2738 struct btrfs_key *key,
2739 struct btrfs_path *path, int lowest)
2740{
2741 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2742 struct backref_node *upper;
2743 struct backref_edge *edge;
2744 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2745 struct btrfs_root *root;
2746 struct extent_buffer *eb;
2747 u32 blocksize;
2748 u64 bytenr;
2749 u64 generation;
2750 int slot;
2751 int ret;
2752 int err = 0;
2753
2754 BUG_ON(lowest && node->eb);
2755
2756 path->lowest_level = node->level + 1;
2757 rc->backref_cache.path[node->level] = node;
2758 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2759 struct btrfs_key first_key;
2760 struct btrfs_ref ref = { 0 };
2761
2762 cond_resched();
2763
2764 upper = edge->node[UPPER];
2765 root = select_reloc_root(trans, rc, upper, edges);
2766 BUG_ON(!root);
2767
2768 if (upper->eb && !upper->locked) {
2769 if (!lowest) {
2770 ret = btrfs_bin_search(upper->eb, key,
2771 upper->level, &slot);
2772 if (ret < 0) {
2773 err = ret;
2774 goto next;
2775 }
2776 BUG_ON(ret);
2777 bytenr = btrfs_node_blockptr(upper->eb, slot);
2778 if (node->eb->start == bytenr)
2779 goto next;
2780 }
2781 drop_node_buffer(upper);
2782 }
2783
2784 if (!upper->eb) {
2785 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2786 if (ret) {
2787 if (ret < 0)
2788 err = ret;
2789 else
2790 err = -ENOENT;
2791
2792 btrfs_release_path(path);
2793 break;
2794 }
2795
2796 if (!upper->eb) {
2797 upper->eb = path->nodes[upper->level];
2798 path->nodes[upper->level] = NULL;
2799 } else {
2800 BUG_ON(upper->eb != path->nodes[upper->level]);
2801 }
2802
2803 upper->locked = 1;
2804 path->locks[upper->level] = 0;
2805
2806 slot = path->slots[upper->level];
2807 btrfs_release_path(path);
2808 } else {
2809 ret = btrfs_bin_search(upper->eb, key, upper->level,
2810 &slot);
2811 if (ret < 0) {
2812 err = ret;
2813 goto next;
2814 }
2815 BUG_ON(ret);
2816 }
2817
2818 bytenr = btrfs_node_blockptr(upper->eb, slot);
2819 if (lowest) {
2820 if (bytenr != node->bytenr) {
2821 btrfs_err(root->fs_info,
2822 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2823 bytenr, node->bytenr, slot,
2824 upper->eb->start);
2825 err = -EIO;
2826 goto next;
2827 }
2828 } else {
2829 if (node->eb->start == bytenr)
2830 goto next;
2831 }
2832
2833 blocksize = root->fs_info->nodesize;
2834 generation = btrfs_node_ptr_generation(upper->eb, slot);
2835 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2836 eb = read_tree_block(fs_info, bytenr, generation,
2837 upper->level - 1, &first_key);
2838 if (IS_ERR(eb)) {
2839 err = PTR_ERR(eb);
2840 goto next;
2841 } else if (!extent_buffer_uptodate(eb)) {
2842 free_extent_buffer(eb);
2843 err = -EIO;
2844 goto next;
2845 }
2846 btrfs_tree_lock(eb);
2847 btrfs_set_lock_blocking_write(eb);
2848
2849 if (!node->eb) {
2850 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2851 slot, &eb);
2852 btrfs_tree_unlock(eb);
2853 free_extent_buffer(eb);
2854 if (ret < 0) {
2855 err = ret;
2856 goto next;
2857 }
2858 BUG_ON(node->eb != eb);
2859 } else {
2860 btrfs_set_node_blockptr(upper->eb, slot,
2861 node->eb->start);
2862 btrfs_set_node_ptr_generation(upper->eb, slot,
2863 trans->transid);
2864 btrfs_mark_buffer_dirty(upper->eb);
2865
2866 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2867 node->eb->start, blocksize,
2868 upper->eb->start);
2869 ref.real_root = root->root_key.objectid;
2870 btrfs_init_tree_ref(&ref, node->level,
2871 btrfs_header_owner(upper->eb));
2872 ret = btrfs_inc_extent_ref(trans, &ref);
2873 BUG_ON(ret);
2874
2875 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2876 BUG_ON(ret);
2877 }
2878next:
2879 if (!upper->pending)
2880 drop_node_buffer(upper);
2881 else
2882 unlock_node_buffer(upper);
2883 if (err)
2884 break;
2885 }
2886
2887 if (!err && node->pending) {
2888 drop_node_buffer(node);
2889 list_move_tail(&node->list, &rc->backref_cache.changed);
2890 node->pending = 0;
2891 }
2892
2893 path->lowest_level = 0;
2894 BUG_ON(err == -ENOSPC);
2895 return err;
2896}
2897
2898static int link_to_upper(struct btrfs_trans_handle *trans,
2899 struct reloc_control *rc,
2900 struct backref_node *node,
2901 struct btrfs_path *path)
2902{
2903 struct btrfs_key key;
2904
2905 btrfs_node_key_to_cpu(node->eb, &key, 0);
2906 return do_relocation(trans, rc, node, &key, path, 0);
2907}
2908
2909static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2910 struct reloc_control *rc,
2911 struct btrfs_path *path, int err)
2912{
2913 LIST_HEAD(list);
2914 struct backref_cache *cache = &rc->backref_cache;
2915 struct backref_node *node;
2916 int level;
2917 int ret;
2918
2919 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2920 while (!list_empty(&cache->pending[level])) {
2921 node = list_entry(cache->pending[level].next,
2922 struct backref_node, list);
2923 list_move_tail(&node->list, &list);
2924 BUG_ON(!node->pending);
2925
2926 if (!err) {
2927 ret = link_to_upper(trans, rc, node, path);
2928 if (ret < 0)
2929 err = ret;
2930 }
2931 }
2932 list_splice_init(&list, &cache->pending[level]);
2933 }
2934 return err;
2935}
2936
2937static void mark_block_processed(struct reloc_control *rc,
2938 u64 bytenr, u32 blocksize)
2939{
2940 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2941 EXTENT_DIRTY);
2942}
2943
2944static void __mark_block_processed(struct reloc_control *rc,
2945 struct backref_node *node)
2946{
2947 u32 blocksize;
2948 if (node->level == 0 ||
2949 in_block_group(node->bytenr, rc->block_group)) {
2950 blocksize = rc->extent_root->fs_info->nodesize;
2951 mark_block_processed(rc, node->bytenr, blocksize);
2952 }
2953 node->processed = 1;
2954}
2955
2956/*
2957 * mark a block and all blocks directly/indirectly reference the block
2958 * as processed.
2959 */
2960static void update_processed_blocks(struct reloc_control *rc,
2961 struct backref_node *node)
2962{
2963 struct backref_node *next = node;
2964 struct backref_edge *edge;
2965 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2966 int index = 0;
2967
2968 while (next) {
2969 cond_resched();
2970 while (1) {
2971 if (next->processed)
2972 break;
2973
2974 __mark_block_processed(rc, next);
2975
2976 if (list_empty(&next->upper))
2977 break;
2978
2979 edge = list_entry(next->upper.next,
2980 struct backref_edge, list[LOWER]);
2981 edges[index++] = edge;
2982 next = edge->node[UPPER];
2983 }
2984 next = walk_down_backref(edges, &index);
2985 }
2986}
2987
2988static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2989{
2990 u32 blocksize = rc->extent_root->fs_info->nodesize;
2991
2992 if (test_range_bit(&rc->processed_blocks, bytenr,
2993 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2994 return 1;
2995 return 0;
2996}
2997
2998static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2999 struct tree_block *block)
3000{
3001 struct extent_buffer *eb;
3002
3003 BUG_ON(block->key_ready);
3004 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
3005 block->level, NULL);
3006 if (IS_ERR(eb)) {
3007 return PTR_ERR(eb);
3008 } else if (!extent_buffer_uptodate(eb)) {
3009 free_extent_buffer(eb);
3010 return -EIO;
3011 }
3012 if (block->level == 0)
3013 btrfs_item_key_to_cpu(eb, &block->key, 0);
3014 else
3015 btrfs_node_key_to_cpu(eb, &block->key, 0);
3016 free_extent_buffer(eb);
3017 block->key_ready = 1;
3018 return 0;
3019}
3020
3021/*
3022 * helper function to relocate a tree block
3023 */
3024static int relocate_tree_block(struct btrfs_trans_handle *trans,
3025 struct reloc_control *rc,
3026 struct backref_node *node,
3027 struct btrfs_key *key,
3028 struct btrfs_path *path)
3029{
3030 struct btrfs_root *root;
3031 int ret = 0;
3032
3033 if (!node)
3034 return 0;
3035
3036 BUG_ON(node->processed);
3037 root = select_one_root(node);
3038 if (root == ERR_PTR(-ENOENT)) {
3039 update_processed_blocks(rc, node);
3040 goto out;
3041 }
3042
3043 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3044 ret = reserve_metadata_space(trans, rc, node);
3045 if (ret)
3046 goto out;
3047 }
3048
3049 if (root) {
3050 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3051 BUG_ON(node->new_bytenr);
3052 BUG_ON(!list_empty(&node->list));
3053 btrfs_record_root_in_trans(trans, root);
3054 root = root->reloc_root;
3055 node->new_bytenr = root->node->start;
3056 node->root = root;
3057 list_add_tail(&node->list, &rc->backref_cache.changed);
3058 } else {
3059 path->lowest_level = node->level;
3060 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3061 btrfs_release_path(path);
3062 if (ret > 0)
3063 ret = 0;
3064 }
3065 if (!ret)
3066 update_processed_blocks(rc, node);
3067 } else {
3068 ret = do_relocation(trans, rc, node, key, path, 1);
3069 }
3070out:
3071 if (ret || node->level == 0 || node->cowonly)
3072 remove_backref_node(&rc->backref_cache, node);
3073 return ret;
3074}
3075
3076/*
3077 * relocate a list of blocks
3078 */
3079static noinline_for_stack
3080int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3081 struct reloc_control *rc, struct rb_root *blocks)
3082{
3083 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3084 struct backref_node *node;
3085 struct btrfs_path *path;
3086 struct tree_block *block;
3087 struct tree_block *next;
3088 int ret;
3089 int err = 0;
3090
3091 path = btrfs_alloc_path();
3092 if (!path) {
3093 err = -ENOMEM;
3094 goto out_free_blocks;
3095 }
3096
3097 /* Kick in readahead for tree blocks with missing keys */
3098 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3099 if (!block->key_ready)
3100 readahead_tree_block(fs_info, block->bytenr);
3101 }
3102
3103 /* Get first keys */
3104 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3105 if (!block->key_ready) {
3106 err = get_tree_block_key(fs_info, block);
3107 if (err)
3108 goto out_free_path;
3109 }
3110 }
3111
3112 /* Do tree relocation */
3113 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3114 node = build_backref_tree(rc, &block->key,
3115 block->level, block->bytenr);
3116 if (IS_ERR(node)) {
3117 err = PTR_ERR(node);
3118 goto out;
3119 }
3120
3121 ret = relocate_tree_block(trans, rc, node, &block->key,
3122 path);
3123 if (ret < 0) {
3124 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3125 err = ret;
3126 goto out;
3127 }
3128 }
3129out:
3130 err = finish_pending_nodes(trans, rc, path, err);
3131
3132out_free_path:
3133 btrfs_free_path(path);
3134out_free_blocks:
3135 free_block_list(blocks);
3136 return err;
3137}
3138
3139static noinline_for_stack
3140int prealloc_file_extent_cluster(struct inode *inode,
3141 struct file_extent_cluster *cluster)
3142{
3143 u64 alloc_hint = 0;
3144 u64 start;
3145 u64 end;
3146 u64 offset = BTRFS_I(inode)->index_cnt;
3147 u64 num_bytes;
3148 int nr = 0;
3149 int ret = 0;
3150 u64 prealloc_start = cluster->start - offset;
3151 u64 prealloc_end = cluster->end - offset;
3152 u64 cur_offset;
3153 struct extent_changeset *data_reserved = NULL;
3154
3155 BUG_ON(cluster->start != cluster->boundary[0]);
3156 inode_lock(inode);
3157
3158 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3159 prealloc_end + 1 - prealloc_start);
3160 if (ret)
3161 goto out;
3162
3163 cur_offset = prealloc_start;
3164 while (nr < cluster->nr) {
3165 start = cluster->boundary[nr] - offset;
3166 if (nr + 1 < cluster->nr)
3167 end = cluster->boundary[nr + 1] - 1 - offset;
3168 else
3169 end = cluster->end - offset;
3170
3171 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3172 num_bytes = end + 1 - start;
3173 if (cur_offset < start)
3174 btrfs_free_reserved_data_space(inode, data_reserved,
3175 cur_offset, start - cur_offset);
3176 ret = btrfs_prealloc_file_range(inode, 0, start,
3177 num_bytes, num_bytes,
3178 end + 1, &alloc_hint);
3179 cur_offset = end + 1;
3180 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3181 if (ret)
3182 break;
3183 nr++;
3184 }
3185 if (cur_offset < prealloc_end)
3186 btrfs_free_reserved_data_space(inode, data_reserved,
3187 cur_offset, prealloc_end + 1 - cur_offset);
3188out:
3189 inode_unlock(inode);
3190 extent_changeset_free(data_reserved);
3191 return ret;
3192}
3193
3194static noinline_for_stack
3195int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3196 u64 block_start)
3197{
3198 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3199 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3200 struct extent_map *em;
3201 int ret = 0;
3202
3203 em = alloc_extent_map();
3204 if (!em)
3205 return -ENOMEM;
3206
3207 em->start = start;
3208 em->len = end + 1 - start;
3209 em->block_len = em->len;
3210 em->block_start = block_start;
3211 em->bdev = fs_info->fs_devices->latest_bdev;
3212 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3213
3214 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3215 while (1) {
3216 write_lock(&em_tree->lock);
3217 ret = add_extent_mapping(em_tree, em, 0);
3218 write_unlock(&em_tree->lock);
3219 if (ret != -EEXIST) {
3220 free_extent_map(em);
3221 break;
3222 }
3223 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3224 }
3225 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3226 return ret;
3227}
3228
3229static int relocate_file_extent_cluster(struct inode *inode,
3230 struct file_extent_cluster *cluster)
3231{
3232 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3233 u64 page_start;
3234 u64 page_end;
3235 u64 offset = BTRFS_I(inode)->index_cnt;
3236 unsigned long index;
3237 unsigned long last_index;
3238 struct page *page;
3239 struct file_ra_state *ra;
3240 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3241 int nr = 0;
3242 int ret = 0;
3243
3244 if (!cluster->nr)
3245 return 0;
3246
3247 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3248 if (!ra)
3249 return -ENOMEM;
3250
3251 ret = prealloc_file_extent_cluster(inode, cluster);
3252 if (ret)
3253 goto out;
3254
3255 file_ra_state_init(ra, inode->i_mapping);
3256
3257 ret = setup_extent_mapping(inode, cluster->start - offset,
3258 cluster->end - offset, cluster->start);
3259 if (ret)
3260 goto out;
3261
3262 index = (cluster->start - offset) >> PAGE_SHIFT;
3263 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3264 while (index <= last_index) {
3265 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3266 PAGE_SIZE);
3267 if (ret)
3268 goto out;
3269
3270 page = find_lock_page(inode->i_mapping, index);
3271 if (!page) {
3272 page_cache_sync_readahead(inode->i_mapping,
3273 ra, NULL, index,
3274 last_index + 1 - index);
3275 page = find_or_create_page(inode->i_mapping, index,
3276 mask);
3277 if (!page) {
3278 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3279 PAGE_SIZE, true);
3280 btrfs_delalloc_release_extents(BTRFS_I(inode),
3281 PAGE_SIZE);
3282 ret = -ENOMEM;
3283 goto out;
3284 }
3285 }
3286
3287 if (PageReadahead(page)) {
3288 page_cache_async_readahead(inode->i_mapping,
3289 ra, NULL, page, index,
3290 last_index + 1 - index);
3291 }
3292
3293 if (!PageUptodate(page)) {
3294 btrfs_readpage(NULL, page);
3295 lock_page(page);
3296 if (!PageUptodate(page)) {
3297 unlock_page(page);
3298 put_page(page);
3299 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3300 PAGE_SIZE, true);
3301 btrfs_delalloc_release_extents(BTRFS_I(inode),
3302 PAGE_SIZE);
3303 ret = -EIO;
3304 goto out;
3305 }
3306 }
3307
3308 page_start = page_offset(page);
3309 page_end = page_start + PAGE_SIZE - 1;
3310
3311 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3312
3313 set_page_extent_mapped(page);
3314
3315 if (nr < cluster->nr &&
3316 page_start + offset == cluster->boundary[nr]) {
3317 set_extent_bits(&BTRFS_I(inode)->io_tree,
3318 page_start, page_end,
3319 EXTENT_BOUNDARY);
3320 nr++;
3321 }
3322
3323 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3324 NULL);
3325 if (ret) {
3326 unlock_page(page);
3327 put_page(page);
3328 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3329 PAGE_SIZE, true);
3330 btrfs_delalloc_release_extents(BTRFS_I(inode),
3331 PAGE_SIZE);
3332
3333 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3334 page_start, page_end,
3335 EXTENT_LOCKED | EXTENT_BOUNDARY);
3336 goto out;
3337
3338 }
3339 set_page_dirty(page);
3340
3341 unlock_extent(&BTRFS_I(inode)->io_tree,
3342 page_start, page_end);
3343 unlock_page(page);
3344 put_page(page);
3345
3346 index++;
3347 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
3348 balance_dirty_pages_ratelimited(inode->i_mapping);
3349 btrfs_throttle(fs_info);
3350 }
3351 WARN_ON(nr != cluster->nr);
3352out:
3353 kfree(ra);
3354 return ret;
3355}
3356
3357static noinline_for_stack
3358int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3359 struct file_extent_cluster *cluster)
3360{
3361 int ret;
3362
3363 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3364 ret = relocate_file_extent_cluster(inode, cluster);
3365 if (ret)
3366 return ret;
3367 cluster->nr = 0;
3368 }
3369
3370 if (!cluster->nr)
3371 cluster->start = extent_key->objectid;
3372 else
3373 BUG_ON(cluster->nr >= MAX_EXTENTS);
3374 cluster->end = extent_key->objectid + extent_key->offset - 1;
3375 cluster->boundary[cluster->nr] = extent_key->objectid;
3376 cluster->nr++;
3377
3378 if (cluster->nr >= MAX_EXTENTS) {
3379 ret = relocate_file_extent_cluster(inode, cluster);
3380 if (ret)
3381 return ret;
3382 cluster->nr = 0;
3383 }
3384 return 0;
3385}
3386
3387/*
3388 * helper to add a tree block to the list.
3389 * the major work is getting the generation and level of the block
3390 */
3391static int add_tree_block(struct reloc_control *rc,
3392 struct btrfs_key *extent_key,
3393 struct btrfs_path *path,
3394 struct rb_root *blocks)
3395{
3396 struct extent_buffer *eb;
3397 struct btrfs_extent_item *ei;
3398 struct btrfs_tree_block_info *bi;
3399 struct tree_block *block;
3400 struct rb_node *rb_node;
3401 u32 item_size;
3402 int level = -1;
3403 u64 generation;
3404
3405 eb = path->nodes[0];
3406 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3407
3408 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3409 item_size >= sizeof(*ei) + sizeof(*bi)) {
3410 ei = btrfs_item_ptr(eb, path->slots[0],
3411 struct btrfs_extent_item);
3412 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3413 bi = (struct btrfs_tree_block_info *)(ei + 1);
3414 level = btrfs_tree_block_level(eb, bi);
3415 } else {
3416 level = (int)extent_key->offset;
3417 }
3418 generation = btrfs_extent_generation(eb, ei);
3419 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3420 btrfs_print_v0_err(eb->fs_info);
3421 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3422 return -EINVAL;
3423 } else {
3424 BUG();
3425 }
3426
3427 btrfs_release_path(path);
3428
3429 BUG_ON(level == -1);
3430
3431 block = kmalloc(sizeof(*block), GFP_NOFS);
3432 if (!block)
3433 return -ENOMEM;
3434
3435 block->bytenr = extent_key->objectid;
3436 block->key.objectid = rc->extent_root->fs_info->nodesize;
3437 block->key.offset = generation;
3438 block->level = level;
3439 block->key_ready = 0;
3440
3441 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3442 if (rb_node)
3443 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3444
3445 return 0;
3446}
3447
3448/*
3449 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3450 */
3451static int __add_tree_block(struct reloc_control *rc,
3452 u64 bytenr, u32 blocksize,
3453 struct rb_root *blocks)
3454{
3455 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3456 struct btrfs_path *path;
3457 struct btrfs_key key;
3458 int ret;
3459 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3460
3461 if (tree_block_processed(bytenr, rc))
3462 return 0;
3463
3464 if (tree_search(blocks, bytenr))
3465 return 0;
3466
3467 path = btrfs_alloc_path();
3468 if (!path)
3469 return -ENOMEM;
3470again:
3471 key.objectid = bytenr;
3472 if (skinny) {
3473 key.type = BTRFS_METADATA_ITEM_KEY;
3474 key.offset = (u64)-1;
3475 } else {
3476 key.type = BTRFS_EXTENT_ITEM_KEY;
3477 key.offset = blocksize;
3478 }
3479
3480 path->search_commit_root = 1;
3481 path->skip_locking = 1;
3482 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3483 if (ret < 0)
3484 goto out;
3485
3486 if (ret > 0 && skinny) {
3487 if (path->slots[0]) {
3488 path->slots[0]--;
3489 btrfs_item_key_to_cpu(path->nodes[0], &key,
3490 path->slots[0]);
3491 if (key.objectid == bytenr &&
3492 (key.type == BTRFS_METADATA_ITEM_KEY ||
3493 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3494 key.offset == blocksize)))
3495 ret = 0;
3496 }
3497
3498 if (ret) {
3499 skinny = false;
3500 btrfs_release_path(path);
3501 goto again;
3502 }
3503 }
3504 if (ret) {
3505 ASSERT(ret == 1);
3506 btrfs_print_leaf(path->nodes[0]);
3507 btrfs_err(fs_info,
3508 "tree block extent item (%llu) is not found in extent tree",
3509 bytenr);
3510 WARN_ON(1);
3511 ret = -EINVAL;
3512 goto out;
3513 }
3514
3515 ret = add_tree_block(rc, &key, path, blocks);
3516out:
3517 btrfs_free_path(path);
3518 return ret;
3519}
3520
3521/*
3522 * helper to check if the block use full backrefs for pointers in it
3523 */
3524static int block_use_full_backref(struct reloc_control *rc,
3525 struct extent_buffer *eb)
3526{
3527 u64 flags;
3528 int ret;
3529
3530 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3531 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3532 return 1;
3533
3534 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3535 eb->start, btrfs_header_level(eb), 1,
3536 NULL, &flags);
3537 BUG_ON(ret);
3538
3539 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3540 ret = 1;
3541 else
3542 ret = 0;
3543 return ret;
3544}
3545
3546static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3547 struct btrfs_block_group_cache *block_group,
3548 struct inode *inode,
3549 u64 ino)
3550{
3551 struct btrfs_key key;
3552 struct btrfs_root *root = fs_info->tree_root;
3553 struct btrfs_trans_handle *trans;
3554 int ret = 0;
3555
3556 if (inode)
3557 goto truncate;
3558
3559 key.objectid = ino;
3560 key.type = BTRFS_INODE_ITEM_KEY;
3561 key.offset = 0;
3562
3563 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3564 if (IS_ERR(inode))
3565 return -ENOENT;
3566
3567truncate:
3568 ret = btrfs_check_trunc_cache_free_space(fs_info,
3569 &fs_info->global_block_rsv);
3570 if (ret)
3571 goto out;
3572
3573 trans = btrfs_join_transaction(root);
3574 if (IS_ERR(trans)) {
3575 ret = PTR_ERR(trans);
3576 goto out;
3577 }
3578
3579 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3580
3581 btrfs_end_transaction(trans);
3582 btrfs_btree_balance_dirty(fs_info);
3583out:
3584 iput(inode);
3585 return ret;
3586}
3587
3588/*
3589 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3590 * this function scans fs tree to find blocks reference the data extent
3591 */
3592static int find_data_references(struct reloc_control *rc,
3593 struct btrfs_key *extent_key,
3594 struct extent_buffer *leaf,
3595 struct btrfs_extent_data_ref *ref,
3596 struct rb_root *blocks)
3597{
3598 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3599 struct btrfs_path *path;
3600 struct tree_block *block;
3601 struct btrfs_root *root;
3602 struct btrfs_file_extent_item *fi;
3603 struct rb_node *rb_node;
3604 struct btrfs_key key;
3605 u64 ref_root;
3606 u64 ref_objectid;
3607 u64 ref_offset;
3608 u32 ref_count;
3609 u32 nritems;
3610 int err = 0;
3611 int added = 0;
3612 int counted;
3613 int ret;
3614
3615 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3616 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3617 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3618 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3619
3620 /*
3621 * This is an extent belonging to the free space cache, lets just delete
3622 * it and redo the search.
3623 */
3624 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3625 ret = delete_block_group_cache(fs_info, rc->block_group,
3626 NULL, ref_objectid);
3627 if (ret != -ENOENT)
3628 return ret;
3629 ret = 0;
3630 }
3631
3632 path = btrfs_alloc_path();
3633 if (!path)
3634 return -ENOMEM;
3635 path->reada = READA_FORWARD;
3636
3637 root = read_fs_root(fs_info, ref_root);
3638 if (IS_ERR(root)) {
3639 err = PTR_ERR(root);
3640 goto out;
3641 }
3642
3643 key.objectid = ref_objectid;
3644 key.type = BTRFS_EXTENT_DATA_KEY;
3645 if (ref_offset > ((u64)-1 << 32))
3646 key.offset = 0;
3647 else
3648 key.offset = ref_offset;
3649
3650 path->search_commit_root = 1;
3651 path->skip_locking = 1;
3652 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3653 if (ret < 0) {
3654 err = ret;
3655 goto out;
3656 }
3657
3658 leaf = path->nodes[0];
3659 nritems = btrfs_header_nritems(leaf);
3660 /*
3661 * the references in tree blocks that use full backrefs
3662 * are not counted in
3663 */
3664 if (block_use_full_backref(rc, leaf))
3665 counted = 0;
3666 else
3667 counted = 1;
3668 rb_node = tree_search(blocks, leaf->start);
3669 if (rb_node) {
3670 if (counted)
3671 added = 1;
3672 else
3673 path->slots[0] = nritems;
3674 }
3675
3676 while (ref_count > 0) {
3677 while (path->slots[0] >= nritems) {
3678 ret = btrfs_next_leaf(root, path);
3679 if (ret < 0) {
3680 err = ret;
3681 goto out;
3682 }
3683 if (WARN_ON(ret > 0))
3684 goto out;
3685
3686 leaf = path->nodes[0];
3687 nritems = btrfs_header_nritems(leaf);
3688 added = 0;
3689
3690 if (block_use_full_backref(rc, leaf))
3691 counted = 0;
3692 else
3693 counted = 1;
3694 rb_node = tree_search(blocks, leaf->start);
3695 if (rb_node) {
3696 if (counted)
3697 added = 1;
3698 else
3699 path->slots[0] = nritems;
3700 }
3701 }
3702
3703 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3704 if (WARN_ON(key.objectid != ref_objectid ||
3705 key.type != BTRFS_EXTENT_DATA_KEY))
3706 break;
3707
3708 fi = btrfs_item_ptr(leaf, path->slots[0],
3709 struct btrfs_file_extent_item);
3710
3711 if (btrfs_file_extent_type(leaf, fi) ==
3712 BTRFS_FILE_EXTENT_INLINE)
3713 goto next;
3714
3715 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3716 extent_key->objectid)
3717 goto next;
3718
3719 key.offset -= btrfs_file_extent_offset(leaf, fi);
3720 if (key.offset != ref_offset)
3721 goto next;
3722
3723 if (counted)
3724 ref_count--;
3725 if (added)
3726 goto next;
3727
3728 if (!tree_block_processed(leaf->start, rc)) {
3729 block = kmalloc(sizeof(*block), GFP_NOFS);
3730 if (!block) {
3731 err = -ENOMEM;
3732 break;
3733 }
3734 block->bytenr = leaf->start;
3735 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3736 block->level = 0;
3737 block->key_ready = 1;
3738 rb_node = tree_insert(blocks, block->bytenr,
3739 &block->rb_node);
3740 if (rb_node)
3741 backref_tree_panic(rb_node, -EEXIST,
3742 block->bytenr);
3743 }
3744 if (counted)
3745 added = 1;
3746 else
3747 path->slots[0] = nritems;
3748next:
3749 path->slots[0]++;
3750
3751 }
3752out:
3753 btrfs_free_path(path);
3754 return err;
3755}
3756
3757/*
3758 * helper to find all tree blocks that reference a given data extent
3759 */
3760static noinline_for_stack
3761int add_data_references(struct reloc_control *rc,
3762 struct btrfs_key *extent_key,
3763 struct btrfs_path *path,
3764 struct rb_root *blocks)
3765{
3766 struct btrfs_key key;
3767 struct extent_buffer *eb;
3768 struct btrfs_extent_data_ref *dref;
3769 struct btrfs_extent_inline_ref *iref;
3770 unsigned long ptr;
3771 unsigned long end;
3772 u32 blocksize = rc->extent_root->fs_info->nodesize;
3773 int ret = 0;
3774 int err = 0;
3775
3776 eb = path->nodes[0];
3777 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3778 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3779 ptr += sizeof(struct btrfs_extent_item);
3780
3781 while (ptr < end) {
3782 iref = (struct btrfs_extent_inline_ref *)ptr;
3783 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3784 BTRFS_REF_TYPE_DATA);
3785 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3786 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3787 ret = __add_tree_block(rc, key.offset, blocksize,
3788 blocks);
3789 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3790 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3791 ret = find_data_references(rc, extent_key,
3792 eb, dref, blocks);
3793 } else {
3794 ret = -EUCLEAN;
3795 btrfs_err(rc->extent_root->fs_info,
3796 "extent %llu slot %d has an invalid inline ref type",
3797 eb->start, path->slots[0]);
3798 }
3799 if (ret) {
3800 err = ret;
3801 goto out;
3802 }
3803 ptr += btrfs_extent_inline_ref_size(key.type);
3804 }
3805 WARN_ON(ptr > end);
3806
3807 while (1) {
3808 cond_resched();
3809 eb = path->nodes[0];
3810 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3811 ret = btrfs_next_leaf(rc->extent_root, path);
3812 if (ret < 0) {
3813 err = ret;
3814 break;
3815 }
3816 if (ret > 0)
3817 break;
3818 eb = path->nodes[0];
3819 }
3820
3821 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3822 if (key.objectid != extent_key->objectid)
3823 break;
3824
3825 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3826 ret = __add_tree_block(rc, key.offset, blocksize,
3827 blocks);
3828 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3829 dref = btrfs_item_ptr(eb, path->slots[0],
3830 struct btrfs_extent_data_ref);
3831 ret = find_data_references(rc, extent_key,
3832 eb, dref, blocks);
3833 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3834 btrfs_print_v0_err(eb->fs_info);
3835 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3836 ret = -EINVAL;
3837 } else {
3838 ret = 0;
3839 }
3840 if (ret) {
3841 err = ret;
3842 break;
3843 }
3844 path->slots[0]++;
3845 }
3846out:
3847 btrfs_release_path(path);
3848 if (err)
3849 free_block_list(blocks);
3850 return err;
3851}
3852
3853/*
3854 * helper to find next unprocessed extent
3855 */
3856static noinline_for_stack
3857int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3858 struct btrfs_key *extent_key)
3859{
3860 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3861 struct btrfs_key key;
3862 struct extent_buffer *leaf;
3863 u64 start, end, last;
3864 int ret;
3865
3866 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3867 while (1) {
3868 cond_resched();
3869 if (rc->search_start >= last) {
3870 ret = 1;
3871 break;
3872 }
3873
3874 key.objectid = rc->search_start;
3875 key.type = BTRFS_EXTENT_ITEM_KEY;
3876 key.offset = 0;
3877
3878 path->search_commit_root = 1;
3879 path->skip_locking = 1;
3880 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3881 0, 0);
3882 if (ret < 0)
3883 break;
3884next:
3885 leaf = path->nodes[0];
3886 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3887 ret = btrfs_next_leaf(rc->extent_root, path);
3888 if (ret != 0)
3889 break;
3890 leaf = path->nodes[0];
3891 }
3892
3893 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3894 if (key.objectid >= last) {
3895 ret = 1;
3896 break;
3897 }
3898
3899 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3900 key.type != BTRFS_METADATA_ITEM_KEY) {
3901 path->slots[0]++;
3902 goto next;
3903 }
3904
3905 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3906 key.objectid + key.offset <= rc->search_start) {
3907 path->slots[0]++;
3908 goto next;
3909 }
3910
3911 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3912 key.objectid + fs_info->nodesize <=
3913 rc->search_start) {
3914 path->slots[0]++;
3915 goto next;
3916 }
3917
3918 ret = find_first_extent_bit(&rc->processed_blocks,
3919 key.objectid, &start, &end,
3920 EXTENT_DIRTY, NULL);
3921
3922 if (ret == 0 && start <= key.objectid) {
3923 btrfs_release_path(path);
3924 rc->search_start = end + 1;
3925 } else {
3926 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3927 rc->search_start = key.objectid + key.offset;
3928 else
3929 rc->search_start = key.objectid +
3930 fs_info->nodesize;
3931 memcpy(extent_key, &key, sizeof(key));
3932 return 0;
3933 }
3934 }
3935 btrfs_release_path(path);
3936 return ret;
3937}
3938
3939static void set_reloc_control(struct reloc_control *rc)
3940{
3941 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3942
3943 mutex_lock(&fs_info->reloc_mutex);
3944 fs_info->reloc_ctl = rc;
3945 mutex_unlock(&fs_info->reloc_mutex);
3946}
3947
3948static void unset_reloc_control(struct reloc_control *rc)
3949{
3950 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3951
3952 mutex_lock(&fs_info->reloc_mutex);
3953 fs_info->reloc_ctl = NULL;
3954 mutex_unlock(&fs_info->reloc_mutex);
3955}
3956
3957static int check_extent_flags(u64 flags)
3958{
3959 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3960 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3961 return 1;
3962 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3963 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3964 return 1;
3965 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3966 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3967 return 1;
3968 return 0;
3969}
3970
3971static noinline_for_stack
3972int prepare_to_relocate(struct reloc_control *rc)
3973{
3974 struct btrfs_trans_handle *trans;
3975 int ret;
3976
3977 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3978 BTRFS_BLOCK_RSV_TEMP);
3979 if (!rc->block_rsv)
3980 return -ENOMEM;
3981
3982 memset(&rc->cluster, 0, sizeof(rc->cluster));
3983 rc->search_start = rc->block_group->key.objectid;
3984 rc->extents_found = 0;
3985 rc->nodes_relocated = 0;
3986 rc->merging_rsv_size = 0;
3987 rc->reserved_bytes = 0;
3988 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3989 RELOCATION_RESERVED_NODES;
3990 ret = btrfs_block_rsv_refill(rc->extent_root,
3991 rc->block_rsv, rc->block_rsv->size,
3992 BTRFS_RESERVE_FLUSH_ALL);
3993 if (ret)
3994 return ret;
3995
3996 rc->create_reloc_tree = 1;
3997 set_reloc_control(rc);
3998
3999 trans = btrfs_join_transaction(rc->extent_root);
4000 if (IS_ERR(trans)) {
4001 unset_reloc_control(rc);
4002 /*
4003 * extent tree is not a ref_cow tree and has no reloc_root to
4004 * cleanup. And callers are responsible to free the above
4005 * block rsv.
4006 */
4007 return PTR_ERR(trans);
4008 }
4009 btrfs_commit_transaction(trans);
4010 return 0;
4011}
4012
4013static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4014{
4015 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4016 struct rb_root blocks = RB_ROOT;
4017 struct btrfs_key key;
4018 struct btrfs_trans_handle *trans = NULL;
4019 struct btrfs_path *path;
4020 struct btrfs_extent_item *ei;
4021 u64 flags;
4022 u32 item_size;
4023 int ret;
4024 int err = 0;
4025 int progress = 0;
4026
4027 path = btrfs_alloc_path();
4028 if (!path)
4029 return -ENOMEM;
4030 path->reada = READA_FORWARD;
4031
4032 ret = prepare_to_relocate(rc);
4033 if (ret) {
4034 err = ret;
4035 goto out_free;
4036 }
4037
4038 while (1) {
4039 rc->reserved_bytes = 0;
4040 ret = btrfs_block_rsv_refill(rc->extent_root,
4041 rc->block_rsv, rc->block_rsv->size,
4042 BTRFS_RESERVE_FLUSH_ALL);
4043 if (ret) {
4044 err = ret;
4045 break;
4046 }
4047 progress++;
4048 trans = btrfs_start_transaction(rc->extent_root, 0);
4049 if (IS_ERR(trans)) {
4050 err = PTR_ERR(trans);
4051 trans = NULL;
4052 break;
4053 }
4054restart:
4055 if (update_backref_cache(trans, &rc->backref_cache)) {
4056 btrfs_end_transaction(trans);
4057 trans = NULL;
4058 continue;
4059 }
4060
4061 ret = find_next_extent(rc, path, &key);
4062 if (ret < 0)
4063 err = ret;
4064 if (ret != 0)
4065 break;
4066
4067 rc->extents_found++;
4068
4069 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4070 struct btrfs_extent_item);
4071 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4072 if (item_size >= sizeof(*ei)) {
4073 flags = btrfs_extent_flags(path->nodes[0], ei);
4074 ret = check_extent_flags(flags);
4075 BUG_ON(ret);
4076 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4077 err = -EINVAL;
4078 btrfs_print_v0_err(trans->fs_info);
4079 btrfs_abort_transaction(trans, err);
4080 break;
4081 } else {
4082 BUG();
4083 }
4084
4085 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4086 ret = add_tree_block(rc, &key, path, &blocks);
4087 } else if (rc->stage == UPDATE_DATA_PTRS &&
4088 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4089 ret = add_data_references(rc, &key, path, &blocks);
4090 } else {
4091 btrfs_release_path(path);
4092 ret = 0;
4093 }
4094 if (ret < 0) {
4095 err = ret;
4096 break;
4097 }
4098
4099 if (!RB_EMPTY_ROOT(&blocks)) {
4100 ret = relocate_tree_blocks(trans, rc, &blocks);
4101 if (ret < 0) {
4102 /*
4103 * if we fail to relocate tree blocks, force to update
4104 * backref cache when committing transaction.
4105 */
4106 rc->backref_cache.last_trans = trans->transid - 1;
4107
4108 if (ret != -EAGAIN) {
4109 err = ret;
4110 break;
4111 }
4112 rc->extents_found--;
4113 rc->search_start = key.objectid;
4114 }
4115 }
4116
4117 btrfs_end_transaction_throttle(trans);
4118 btrfs_btree_balance_dirty(fs_info);
4119 trans = NULL;
4120
4121 if (rc->stage == MOVE_DATA_EXTENTS &&
4122 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4123 rc->found_file_extent = 1;
4124 ret = relocate_data_extent(rc->data_inode,
4125 &key, &rc->cluster);
4126 if (ret < 0) {
4127 err = ret;
4128 break;
4129 }
4130 }
4131 }
4132 if (trans && progress && err == -ENOSPC) {
4133 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4134 if (ret == 1) {
4135 err = 0;
4136 progress = 0;
4137 goto restart;
4138 }
4139 }
4140
4141 btrfs_release_path(path);
4142 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4143
4144 if (trans) {
4145 btrfs_end_transaction_throttle(trans);
4146 btrfs_btree_balance_dirty(fs_info);
4147 }
4148
4149 if (!err) {
4150 ret = relocate_file_extent_cluster(rc->data_inode,
4151 &rc->cluster);
4152 if (ret < 0)
4153 err = ret;
4154 }
4155
4156 rc->create_reloc_tree = 0;
4157 set_reloc_control(rc);
4158
4159 backref_cache_cleanup(&rc->backref_cache);
4160 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4161
4162 err = prepare_to_merge(rc, err);
4163
4164 merge_reloc_roots(rc);
4165
4166 rc->merge_reloc_tree = 0;
4167 unset_reloc_control(rc);
4168 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4169
4170 /* get rid of pinned extents */
4171 trans = btrfs_join_transaction(rc->extent_root);
4172 if (IS_ERR(trans)) {
4173 err = PTR_ERR(trans);
4174 goto out_free;
4175 }
4176 btrfs_commit_transaction(trans);
4177 ret = clean_dirty_subvols(rc);
4178 if (ret < 0 && !err)
4179 err = ret;
4180out_free:
4181 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4182 btrfs_free_path(path);
4183 return err;
4184}
4185
4186static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4187 struct btrfs_root *root, u64 objectid)
4188{
4189 struct btrfs_path *path;
4190 struct btrfs_inode_item *item;
4191 struct extent_buffer *leaf;
4192 int ret;
4193
4194 path = btrfs_alloc_path();
4195 if (!path)
4196 return -ENOMEM;
4197
4198 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4199 if (ret)
4200 goto out;
4201
4202 leaf = path->nodes[0];
4203 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4204 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4205 btrfs_set_inode_generation(leaf, item, 1);
4206 btrfs_set_inode_size(leaf, item, 0);
4207 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4208 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4209 BTRFS_INODE_PREALLOC);
4210 btrfs_mark_buffer_dirty(leaf);
4211out:
4212 btrfs_free_path(path);
4213 return ret;
4214}
4215
4216/*
4217 * helper to create inode for data relocation.
4218 * the inode is in data relocation tree and its link count is 0
4219 */
4220static noinline_for_stack
4221struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4222 struct btrfs_block_group_cache *group)
4223{
4224 struct inode *inode = NULL;
4225 struct btrfs_trans_handle *trans;
4226 struct btrfs_root *root;
4227 struct btrfs_key key;
4228 u64 objectid;
4229 int err = 0;
4230
4231 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4232 if (IS_ERR(root))
4233 return ERR_CAST(root);
4234
4235 trans = btrfs_start_transaction(root, 6);
4236 if (IS_ERR(trans))
4237 return ERR_CAST(trans);
4238
4239 err = btrfs_find_free_objectid(root, &objectid);
4240 if (err)
4241 goto out;
4242
4243 err = __insert_orphan_inode(trans, root, objectid);
4244 BUG_ON(err);
4245
4246 key.objectid = objectid;
4247 key.type = BTRFS_INODE_ITEM_KEY;
4248 key.offset = 0;
4249 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4250 BUG_ON(IS_ERR(inode));
4251 BTRFS_I(inode)->index_cnt = group->key.objectid;
4252
4253 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4254out:
4255 btrfs_end_transaction(trans);
4256 btrfs_btree_balance_dirty(fs_info);
4257 if (err) {
4258 if (inode)
4259 iput(inode);
4260 inode = ERR_PTR(err);
4261 }
4262 return inode;
4263}
4264
4265static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4266{
4267 struct reloc_control *rc;
4268
4269 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4270 if (!rc)
4271 return NULL;
4272
4273 INIT_LIST_HEAD(&rc->reloc_roots);
4274 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4275 backref_cache_init(&rc->backref_cache);
4276 mapping_tree_init(&rc->reloc_root_tree);
4277 extent_io_tree_init(fs_info, &rc->processed_blocks,
4278 IO_TREE_RELOC_BLOCKS, NULL);
4279 return rc;
4280}
4281
4282/*
4283 * Print the block group being relocated
4284 */
4285static void describe_relocation(struct btrfs_fs_info *fs_info,
4286 struct btrfs_block_group_cache *block_group)
4287{
4288 char buf[128] = {'\0'};
4289
4290 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4291
4292 btrfs_info(fs_info,
4293 "relocating block group %llu flags %s",
4294 block_group->key.objectid, buf);
4295}
4296
4297/*
4298 * function to relocate all extents in a block group.
4299 */
4300int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4301{
4302 struct btrfs_block_group_cache *bg;
4303 struct btrfs_root *extent_root = fs_info->extent_root;
4304 struct reloc_control *rc;
4305 struct inode *inode;
4306 struct btrfs_path *path;
4307 int ret;
4308 int rw = 0;
4309 int err = 0;
4310
4311 bg = btrfs_lookup_block_group(fs_info, group_start);
4312 if (!bg)
4313 return -ENOENT;
4314
4315 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4316 btrfs_put_block_group(bg);
4317 return -ETXTBSY;
4318 }
4319
4320 rc = alloc_reloc_control(fs_info);
4321 if (!rc) {
4322 btrfs_put_block_group(bg);
4323 return -ENOMEM;
4324 }
4325
4326 rc->extent_root = extent_root;
4327 rc->block_group = bg;
4328
4329 ret = btrfs_inc_block_group_ro(rc->block_group);
4330 if (ret) {
4331 err = ret;
4332 goto out;
4333 }
4334 rw = 1;
4335
4336 path = btrfs_alloc_path();
4337 if (!path) {
4338 err = -ENOMEM;
4339 goto out;
4340 }
4341
4342 inode = lookup_free_space_inode(rc->block_group, path);
4343 btrfs_free_path(path);
4344
4345 if (!IS_ERR(inode))
4346 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4347 else
4348 ret = PTR_ERR(inode);
4349
4350 if (ret && ret != -ENOENT) {
4351 err = ret;
4352 goto out;
4353 }
4354
4355 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4356 if (IS_ERR(rc->data_inode)) {
4357 err = PTR_ERR(rc->data_inode);
4358 rc->data_inode = NULL;
4359 goto out;
4360 }
4361
4362 describe_relocation(fs_info, rc->block_group);
4363
4364 btrfs_wait_block_group_reservations(rc->block_group);
4365 btrfs_wait_nocow_writers(rc->block_group);
4366 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4367 rc->block_group->key.objectid,
4368 rc->block_group->key.offset);
4369
4370 while (1) {
4371 mutex_lock(&fs_info->cleaner_mutex);
4372 ret = relocate_block_group(rc);
4373 mutex_unlock(&fs_info->cleaner_mutex);
4374 if (ret < 0)
4375 err = ret;
4376
4377 /*
4378 * We may have gotten ENOSPC after we already dirtied some
4379 * extents. If writeout happens while we're relocating a
4380 * different block group we could end up hitting the
4381 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4382 * btrfs_reloc_cow_block. Make sure we write everything out
4383 * properly so we don't trip over this problem, and then break
4384 * out of the loop if we hit an error.
4385 */
4386 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4387 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4388 (u64)-1);
4389 if (ret)
4390 err = ret;
4391 invalidate_mapping_pages(rc->data_inode->i_mapping,
4392 0, -1);
4393 rc->stage = UPDATE_DATA_PTRS;
4394 }
4395
4396 if (err < 0)
4397 goto out;
4398
4399 if (rc->extents_found == 0)
4400 break;
4401
4402 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4403
4404 }
4405
4406 WARN_ON(rc->block_group->pinned > 0);
4407 WARN_ON(rc->block_group->reserved > 0);
4408 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4409out:
4410 if (err && rw)
4411 btrfs_dec_block_group_ro(rc->block_group);
4412 iput(rc->data_inode);
4413 btrfs_put_block_group(rc->block_group);
4414 kfree(rc);
4415 return err;
4416}
4417
4418static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4419{
4420 struct btrfs_fs_info *fs_info = root->fs_info;
4421 struct btrfs_trans_handle *trans;
4422 int ret, err;
4423
4424 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4425 if (IS_ERR(trans))
4426 return PTR_ERR(trans);
4427
4428 memset(&root->root_item.drop_progress, 0,
4429 sizeof(root->root_item.drop_progress));
4430 root->root_item.drop_level = 0;
4431 btrfs_set_root_refs(&root->root_item, 0);
4432 ret = btrfs_update_root(trans, fs_info->tree_root,
4433 &root->root_key, &root->root_item);
4434
4435 err = btrfs_end_transaction(trans);
4436 if (err)
4437 return err;
4438 return ret;
4439}
4440
4441/*
4442 * recover relocation interrupted by system crash.
4443 *
4444 * this function resumes merging reloc trees with corresponding fs trees.
4445 * this is important for keeping the sharing of tree blocks
4446 */
4447int btrfs_recover_relocation(struct btrfs_root *root)
4448{
4449 struct btrfs_fs_info *fs_info = root->fs_info;
4450 LIST_HEAD(reloc_roots);
4451 struct btrfs_key key;
4452 struct btrfs_root *fs_root;
4453 struct btrfs_root *reloc_root;
4454 struct btrfs_path *path;
4455 struct extent_buffer *leaf;
4456 struct reloc_control *rc = NULL;
4457 struct btrfs_trans_handle *trans;
4458 int ret;
4459 int err = 0;
4460
4461 path = btrfs_alloc_path();
4462 if (!path)
4463 return -ENOMEM;
4464 path->reada = READA_BACK;
4465
4466 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4467 key.type = BTRFS_ROOT_ITEM_KEY;
4468 key.offset = (u64)-1;
4469
4470 while (1) {
4471 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4472 path, 0, 0);
4473 if (ret < 0) {
4474 err = ret;
4475 goto out;
4476 }
4477 if (ret > 0) {
4478 if (path->slots[0] == 0)
4479 break;
4480 path->slots[0]--;
4481 }
4482 leaf = path->nodes[0];
4483 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4484 btrfs_release_path(path);
4485
4486 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4487 key.type != BTRFS_ROOT_ITEM_KEY)
4488 break;
4489
4490 reloc_root = btrfs_read_fs_root(root, &key);
4491 if (IS_ERR(reloc_root)) {
4492 err = PTR_ERR(reloc_root);
4493 goto out;
4494 }
4495
4496 list_add(&reloc_root->root_list, &reloc_roots);
4497
4498 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4499 fs_root = read_fs_root(fs_info,
4500 reloc_root->root_key.offset);
4501 if (IS_ERR(fs_root)) {
4502 ret = PTR_ERR(fs_root);
4503 if (ret != -ENOENT) {
4504 err = ret;
4505 goto out;
4506 }
4507 ret = mark_garbage_root(reloc_root);
4508 if (ret < 0) {
4509 err = ret;
4510 goto out;
4511 }
4512 }
4513 }
4514
4515 if (key.offset == 0)
4516 break;
4517
4518 key.offset--;
4519 }
4520 btrfs_release_path(path);
4521
4522 if (list_empty(&reloc_roots))
4523 goto out;
4524
4525 rc = alloc_reloc_control(fs_info);
4526 if (!rc) {
4527 err = -ENOMEM;
4528 goto out;
4529 }
4530
4531 rc->extent_root = fs_info->extent_root;
4532
4533 set_reloc_control(rc);
4534
4535 trans = btrfs_join_transaction(rc->extent_root);
4536 if (IS_ERR(trans)) {
4537 unset_reloc_control(rc);
4538 err = PTR_ERR(trans);
4539 goto out_free;
4540 }
4541
4542 rc->merge_reloc_tree = 1;
4543
4544 while (!list_empty(&reloc_roots)) {
4545 reloc_root = list_entry(reloc_roots.next,
4546 struct btrfs_root, root_list);
4547 list_del(&reloc_root->root_list);
4548
4549 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4550 list_add_tail(&reloc_root->root_list,
4551 &rc->reloc_roots);
4552 continue;
4553 }
4554
4555 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4556 if (IS_ERR(fs_root)) {
4557 err = PTR_ERR(fs_root);
4558 goto out_free;
4559 }
4560
4561 err = __add_reloc_root(reloc_root);
4562 BUG_ON(err < 0); /* -ENOMEM or logic error */
4563 fs_root->reloc_root = reloc_root;
4564 }
4565
4566 err = btrfs_commit_transaction(trans);
4567 if (err)
4568 goto out_free;
4569
4570 merge_reloc_roots(rc);
4571
4572 unset_reloc_control(rc);
4573
4574 trans = btrfs_join_transaction(rc->extent_root);
4575 if (IS_ERR(trans)) {
4576 err = PTR_ERR(trans);
4577 goto out_free;
4578 }
4579 err = btrfs_commit_transaction(trans);
4580
4581 ret = clean_dirty_subvols(rc);
4582 if (ret < 0 && !err)
4583 err = ret;
4584out_free:
4585 kfree(rc);
4586out:
4587 if (!list_empty(&reloc_roots))
4588 free_reloc_roots(&reloc_roots);
4589
4590 btrfs_free_path(path);
4591
4592 if (err == 0) {
4593 /* cleanup orphan inode in data relocation tree */
4594 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4595 if (IS_ERR(fs_root))
4596 err = PTR_ERR(fs_root);
4597 else
4598 err = btrfs_orphan_cleanup(fs_root);
4599 }
4600 return err;
4601}
4602
4603/*
4604 * helper to add ordered checksum for data relocation.
4605 *
4606 * cloning checksum properly handles the nodatasum extents.
4607 * it also saves CPU time to re-calculate the checksum.
4608 */
4609int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4610{
4611 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4612 struct btrfs_ordered_sum *sums;
4613 struct btrfs_ordered_extent *ordered;
4614 int ret;
4615 u64 disk_bytenr;
4616 u64 new_bytenr;
4617 LIST_HEAD(list);
4618
4619 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4620 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4621
4622 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4623 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4624 disk_bytenr + len - 1, &list, 0);
4625 if (ret)
4626 goto out;
4627
4628 while (!list_empty(&list)) {
4629 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4630 list_del_init(&sums->list);
4631
4632 /*
4633 * We need to offset the new_bytenr based on where the csum is.
4634 * We need to do this because we will read in entire prealloc
4635 * extents but we may have written to say the middle of the
4636 * prealloc extent, so we need to make sure the csum goes with
4637 * the right disk offset.
4638 *
4639 * We can do this because the data reloc inode refers strictly
4640 * to the on disk bytes, so we don't have to worry about
4641 * disk_len vs real len like with real inodes since it's all
4642 * disk length.
4643 */
4644 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4645 sums->bytenr = new_bytenr;
4646
4647 btrfs_add_ordered_sum(ordered, sums);
4648 }
4649out:
4650 btrfs_put_ordered_extent(ordered);
4651 return ret;
4652}
4653
4654int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4655 struct btrfs_root *root, struct extent_buffer *buf,
4656 struct extent_buffer *cow)
4657{
4658 struct btrfs_fs_info *fs_info = root->fs_info;
4659 struct reloc_control *rc;
4660 struct backref_node *node;
4661 int first_cow = 0;
4662 int level;
4663 int ret = 0;
4664
4665 rc = fs_info->reloc_ctl;
4666 if (!rc)
4667 return 0;
4668
4669 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4670 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4671
4672 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4673 if (buf == root->node)
4674 __update_reloc_root(root, cow->start);
4675 }
4676
4677 level = btrfs_header_level(buf);
4678 if (btrfs_header_generation(buf) <=
4679 btrfs_root_last_snapshot(&root->root_item))
4680 first_cow = 1;
4681
4682 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4683 rc->create_reloc_tree) {
4684 WARN_ON(!first_cow && level == 0);
4685
4686 node = rc->backref_cache.path[level];
4687 BUG_ON(node->bytenr != buf->start &&
4688 node->new_bytenr != buf->start);
4689
4690 drop_node_buffer(node);
4691 extent_buffer_get(cow);
4692 node->eb = cow;
4693 node->new_bytenr = cow->start;
4694
4695 if (!node->pending) {
4696 list_move_tail(&node->list,
4697 &rc->backref_cache.pending[level]);
4698 node->pending = 1;
4699 }
4700
4701 if (first_cow)
4702 __mark_block_processed(rc, node);
4703
4704 if (first_cow && level > 0)
4705 rc->nodes_relocated += buf->len;
4706 }
4707
4708 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4709 ret = replace_file_extents(trans, rc, root, cow);
4710 return ret;
4711}
4712
4713/*
4714 * called before creating snapshot. it calculates metadata reservation
4715 * required for relocating tree blocks in the snapshot
4716 */
4717void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4718 u64 *bytes_to_reserve)
4719{
4720 struct btrfs_root *root = pending->root;
4721 struct reloc_control *rc = root->fs_info->reloc_ctl;
4722
4723 if (!root->reloc_root || !rc)
4724 return;
4725
4726 if (!rc->merge_reloc_tree)
4727 return;
4728
4729 root = root->reloc_root;
4730 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4731 /*
4732 * relocation is in the stage of merging trees. the space
4733 * used by merging a reloc tree is twice the size of
4734 * relocated tree nodes in the worst case. half for cowing
4735 * the reloc tree, half for cowing the fs tree. the space
4736 * used by cowing the reloc tree will be freed after the
4737 * tree is dropped. if we create snapshot, cowing the fs
4738 * tree may use more space than it frees. so we need
4739 * reserve extra space.
4740 */
4741 *bytes_to_reserve += rc->nodes_relocated;
4742}
4743
4744/*
4745 * called after snapshot is created. migrate block reservation
4746 * and create reloc root for the newly created snapshot
4747 */
4748int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4749 struct btrfs_pending_snapshot *pending)
4750{
4751 struct btrfs_root *root = pending->root;
4752 struct btrfs_root *reloc_root;
4753 struct btrfs_root *new_root;
4754 struct reloc_control *rc = root->fs_info->reloc_ctl;
4755 int ret;
4756
4757 if (!root->reloc_root || !rc)
4758 return 0;
4759
4760 rc = root->fs_info->reloc_ctl;
4761 rc->merging_rsv_size += rc->nodes_relocated;
4762
4763 if (rc->merge_reloc_tree) {
4764 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4765 rc->block_rsv,
4766 rc->nodes_relocated, true);
4767 if (ret)
4768 return ret;
4769 }
4770
4771 new_root = pending->snap;
4772 reloc_root = create_reloc_root(trans, root->reloc_root,
4773 new_root->root_key.objectid);
4774 if (IS_ERR(reloc_root))
4775 return PTR_ERR(reloc_root);
4776
4777 ret = __add_reloc_root(reloc_root);
4778 BUG_ON(ret < 0);
4779 new_root->reloc_root = reloc_root;
4780
4781 if (rc->create_reloc_tree)
4782 ret = clone_backref_node(trans, rc, root, reloc_root);
4783 return ret;
4784}
1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Copyright (C) 2009 Oracle. All rights reserved.
4 */
5
6#include <linux/sched.h>
7#include <linux/pagemap.h>
8#include <linux/writeback.h>
9#include <linux/blkdev.h>
10#include <linux/rbtree.h>
11#include <linux/slab.h>
12#include <linux/error-injection.h>
13#include "ctree.h"
14#include "disk-io.h"
15#include "transaction.h"
16#include "volumes.h"
17#include "locking.h"
18#include "btrfs_inode.h"
19#include "async-thread.h"
20#include "free-space-cache.h"
21#include "qgroup.h"
22#include "print-tree.h"
23#include "delalloc-space.h"
24#include "block-group.h"
25#include "backref.h"
26#include "misc.h"
27#include "subpage.h"
28#include "zoned.h"
29#include "inode-item.h"
30#include "space-info.h"
31#include "fs.h"
32#include "accessors.h"
33#include "extent-tree.h"
34#include "root-tree.h"
35#include "file-item.h"
36#include "relocation.h"
37#include "super.h"
38#include "tree-checker.h"
39
40/*
41 * Relocation overview
42 *
43 * [What does relocation do]
44 *
45 * The objective of relocation is to relocate all extents of the target block
46 * group to other block groups.
47 * This is utilized by resize (shrink only), profile converting, compacting
48 * space, or balance routine to spread chunks over devices.
49 *
50 * Before | After
51 * ------------------------------------------------------------------
52 * BG A: 10 data extents | BG A: deleted
53 * BG B: 2 data extents | BG B: 10 data extents (2 old + 8 relocated)
54 * BG C: 1 extents | BG C: 3 data extents (1 old + 2 relocated)
55 *
56 * [How does relocation work]
57 *
58 * 1. Mark the target block group read-only
59 * New extents won't be allocated from the target block group.
60 *
61 * 2.1 Record each extent in the target block group
62 * To build a proper map of extents to be relocated.
63 *
64 * 2.2 Build data reloc tree and reloc trees
65 * Data reloc tree will contain an inode, recording all newly relocated
66 * data extents.
67 * There will be only one data reloc tree for one data block group.
68 *
69 * Reloc tree will be a special snapshot of its source tree, containing
70 * relocated tree blocks.
71 * Each tree referring to a tree block in target block group will get its
72 * reloc tree built.
73 *
74 * 2.3 Swap source tree with its corresponding reloc tree
75 * Each involved tree only refers to new extents after swap.
76 *
77 * 3. Cleanup reloc trees and data reloc tree.
78 * As old extents in the target block group are still referenced by reloc
79 * trees, we need to clean them up before really freeing the target block
80 * group.
81 *
82 * The main complexity is in steps 2.2 and 2.3.
83 *
84 * The entry point of relocation is relocate_block_group() function.
85 */
86
87#define RELOCATION_RESERVED_NODES 256
88/*
89 * map address of tree root to tree
90 */
91struct mapping_node {
92 struct {
93 struct rb_node rb_node;
94 u64 bytenr;
95 }; /* Use rb_simle_node for search/insert */
96 void *data;
97};
98
99struct mapping_tree {
100 struct rb_root rb_root;
101 spinlock_t lock;
102};
103
104/*
105 * present a tree block to process
106 */
107struct tree_block {
108 struct {
109 struct rb_node rb_node;
110 u64 bytenr;
111 }; /* Use rb_simple_node for search/insert */
112 u64 owner;
113 struct btrfs_key key;
114 u8 level;
115 bool key_ready;
116};
117
118#define MAX_EXTENTS 128
119
120struct file_extent_cluster {
121 u64 start;
122 u64 end;
123 u64 boundary[MAX_EXTENTS];
124 unsigned int nr;
125 u64 owning_root;
126};
127
128/* Stages of data relocation. */
129enum reloc_stage {
130 MOVE_DATA_EXTENTS,
131 UPDATE_DATA_PTRS
132};
133
134struct reloc_control {
135 /* block group to relocate */
136 struct btrfs_block_group *block_group;
137 /* extent tree */
138 struct btrfs_root *extent_root;
139 /* inode for moving data */
140 struct inode *data_inode;
141
142 struct btrfs_block_rsv *block_rsv;
143
144 struct btrfs_backref_cache backref_cache;
145
146 struct file_extent_cluster cluster;
147 /* tree blocks have been processed */
148 struct extent_io_tree processed_blocks;
149 /* map start of tree root to corresponding reloc tree */
150 struct mapping_tree reloc_root_tree;
151 /* list of reloc trees */
152 struct list_head reloc_roots;
153 /* list of subvolume trees that get relocated */
154 struct list_head dirty_subvol_roots;
155 /* size of metadata reservation for merging reloc trees */
156 u64 merging_rsv_size;
157 /* size of relocated tree nodes */
158 u64 nodes_relocated;
159 /* reserved size for block group relocation*/
160 u64 reserved_bytes;
161
162 u64 search_start;
163 u64 extents_found;
164
165 enum reloc_stage stage;
166 bool create_reloc_tree;
167 bool merge_reloc_tree;
168 bool found_file_extent;
169};
170
171static void mark_block_processed(struct reloc_control *rc,
172 struct btrfs_backref_node *node)
173{
174 u32 blocksize;
175
176 if (node->level == 0 ||
177 in_range(node->bytenr, rc->block_group->start,
178 rc->block_group->length)) {
179 blocksize = rc->extent_root->fs_info->nodesize;
180 set_extent_bit(&rc->processed_blocks, node->bytenr,
181 node->bytenr + blocksize - 1, EXTENT_DIRTY, NULL);
182 }
183 node->processed = 1;
184}
185
186/*
187 * walk up backref nodes until reach node presents tree root
188 */
189static struct btrfs_backref_node *walk_up_backref(
190 struct btrfs_backref_node *node,
191 struct btrfs_backref_edge *edges[], int *index)
192{
193 struct btrfs_backref_edge *edge;
194 int idx = *index;
195
196 while (!list_empty(&node->upper)) {
197 edge = list_entry(node->upper.next,
198 struct btrfs_backref_edge, list[LOWER]);
199 edges[idx++] = edge;
200 node = edge->node[UPPER];
201 }
202 BUG_ON(node->detached);
203 *index = idx;
204 return node;
205}
206
207/*
208 * walk down backref nodes to find start of next reference path
209 */
210static struct btrfs_backref_node *walk_down_backref(
211 struct btrfs_backref_edge *edges[], int *index)
212{
213 struct btrfs_backref_edge *edge;
214 struct btrfs_backref_node *lower;
215 int idx = *index;
216
217 while (idx > 0) {
218 edge = edges[idx - 1];
219 lower = edge->node[LOWER];
220 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
221 idx--;
222 continue;
223 }
224 edge = list_entry(edge->list[LOWER].next,
225 struct btrfs_backref_edge, list[LOWER]);
226 edges[idx - 1] = edge;
227 *index = idx;
228 return edge->node[UPPER];
229 }
230 *index = 0;
231 return NULL;
232}
233
234static void update_backref_node(struct btrfs_backref_cache *cache,
235 struct btrfs_backref_node *node, u64 bytenr)
236{
237 struct rb_node *rb_node;
238 rb_erase(&node->rb_node, &cache->rb_root);
239 node->bytenr = bytenr;
240 rb_node = rb_simple_insert(&cache->rb_root, node->bytenr, &node->rb_node);
241 if (rb_node)
242 btrfs_backref_panic(cache->fs_info, bytenr, -EEXIST);
243}
244
245/*
246 * update backref cache after a transaction commit
247 */
248static int update_backref_cache(struct btrfs_trans_handle *trans,
249 struct btrfs_backref_cache *cache)
250{
251 struct btrfs_backref_node *node;
252 int level = 0;
253
254 if (cache->last_trans == 0) {
255 cache->last_trans = trans->transid;
256 return 0;
257 }
258
259 if (cache->last_trans == trans->transid)
260 return 0;
261
262 /*
263 * detached nodes are used to avoid unnecessary backref
264 * lookup. transaction commit changes the extent tree.
265 * so the detached nodes are no longer useful.
266 */
267 while (!list_empty(&cache->detached)) {
268 node = list_entry(cache->detached.next,
269 struct btrfs_backref_node, list);
270 btrfs_backref_cleanup_node(cache, node);
271 }
272
273 while (!list_empty(&cache->changed)) {
274 node = list_entry(cache->changed.next,
275 struct btrfs_backref_node, list);
276 list_del_init(&node->list);
277 BUG_ON(node->pending);
278 update_backref_node(cache, node, node->new_bytenr);
279 }
280
281 /*
282 * some nodes can be left in the pending list if there were
283 * errors during processing the pending nodes.
284 */
285 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
286 list_for_each_entry(node, &cache->pending[level], list) {
287 BUG_ON(!node->pending);
288 if (node->bytenr == node->new_bytenr)
289 continue;
290 update_backref_node(cache, node, node->new_bytenr);
291 }
292 }
293
294 cache->last_trans = 0;
295 return 1;
296}
297
298static bool reloc_root_is_dead(const struct btrfs_root *root)
299{
300 /*
301 * Pair with set_bit/clear_bit in clean_dirty_subvols and
302 * btrfs_update_reloc_root. We need to see the updated bit before
303 * trying to access reloc_root
304 */
305 smp_rmb();
306 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
307 return true;
308 return false;
309}
310
311/*
312 * Check if this subvolume tree has valid reloc tree.
313 *
314 * Reloc tree after swap is considered dead, thus not considered as valid.
315 * This is enough for most callers, as they don't distinguish dead reloc root
316 * from no reloc root. But btrfs_should_ignore_reloc_root() below is a
317 * special case.
318 */
319static bool have_reloc_root(const struct btrfs_root *root)
320{
321 if (reloc_root_is_dead(root))
322 return false;
323 if (!root->reloc_root)
324 return false;
325 return true;
326}
327
328bool btrfs_should_ignore_reloc_root(const struct btrfs_root *root)
329{
330 struct btrfs_root *reloc_root;
331
332 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
333 return false;
334
335 /* This root has been merged with its reloc tree, we can ignore it */
336 if (reloc_root_is_dead(root))
337 return true;
338
339 reloc_root = root->reloc_root;
340 if (!reloc_root)
341 return false;
342
343 if (btrfs_header_generation(reloc_root->commit_root) ==
344 root->fs_info->running_transaction->transid)
345 return false;
346 /*
347 * If there is reloc tree and it was created in previous transaction
348 * backref lookup can find the reloc tree, so backref node for the fs
349 * tree root is useless for relocation.
350 */
351 return true;
352}
353
354/*
355 * find reloc tree by address of tree root
356 */
357struct btrfs_root *find_reloc_root(struct btrfs_fs_info *fs_info, u64 bytenr)
358{
359 struct reloc_control *rc = fs_info->reloc_ctl;
360 struct rb_node *rb_node;
361 struct mapping_node *node;
362 struct btrfs_root *root = NULL;
363
364 ASSERT(rc);
365 spin_lock(&rc->reloc_root_tree.lock);
366 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root, bytenr);
367 if (rb_node) {
368 node = rb_entry(rb_node, struct mapping_node, rb_node);
369 root = node->data;
370 }
371 spin_unlock(&rc->reloc_root_tree.lock);
372 return btrfs_grab_root(root);
373}
374
375/*
376 * For useless nodes, do two major clean ups:
377 *
378 * - Cleanup the children edges and nodes
379 * If child node is also orphan (no parent) during cleanup, then the child
380 * node will also be cleaned up.
381 *
382 * - Freeing up leaves (level 0), keeps nodes detached
383 * For nodes, the node is still cached as "detached"
384 *
385 * Return false if @node is not in the @useless_nodes list.
386 * Return true if @node is in the @useless_nodes list.
387 */
388static bool handle_useless_nodes(struct reloc_control *rc,
389 struct btrfs_backref_node *node)
390{
391 struct btrfs_backref_cache *cache = &rc->backref_cache;
392 struct list_head *useless_node = &cache->useless_node;
393 bool ret = false;
394
395 while (!list_empty(useless_node)) {
396 struct btrfs_backref_node *cur;
397
398 cur = list_first_entry(useless_node, struct btrfs_backref_node,
399 list);
400 list_del_init(&cur->list);
401
402 /* Only tree root nodes can be added to @useless_nodes */
403 ASSERT(list_empty(&cur->upper));
404
405 if (cur == node)
406 ret = true;
407
408 /* The node is the lowest node */
409 if (cur->lowest) {
410 list_del_init(&cur->lower);
411 cur->lowest = 0;
412 }
413
414 /* Cleanup the lower edges */
415 while (!list_empty(&cur->lower)) {
416 struct btrfs_backref_edge *edge;
417 struct btrfs_backref_node *lower;
418
419 edge = list_entry(cur->lower.next,
420 struct btrfs_backref_edge, list[UPPER]);
421 list_del(&edge->list[UPPER]);
422 list_del(&edge->list[LOWER]);
423 lower = edge->node[LOWER];
424 btrfs_backref_free_edge(cache, edge);
425
426 /* Child node is also orphan, queue for cleanup */
427 if (list_empty(&lower->upper))
428 list_add(&lower->list, useless_node);
429 }
430 /* Mark this block processed for relocation */
431 mark_block_processed(rc, cur);
432
433 /*
434 * Backref nodes for tree leaves are deleted from the cache.
435 * Backref nodes for upper level tree blocks are left in the
436 * cache to avoid unnecessary backref lookup.
437 */
438 if (cur->level > 0) {
439 list_add(&cur->list, &cache->detached);
440 cur->detached = 1;
441 } else {
442 rb_erase(&cur->rb_node, &cache->rb_root);
443 btrfs_backref_free_node(cache, cur);
444 }
445 }
446 return ret;
447}
448
449/*
450 * Build backref tree for a given tree block. Root of the backref tree
451 * corresponds the tree block, leaves of the backref tree correspond roots of
452 * b-trees that reference the tree block.
453 *
454 * The basic idea of this function is check backrefs of a given block to find
455 * upper level blocks that reference the block, and then check backrefs of
456 * these upper level blocks recursively. The recursion stops when tree root is
457 * reached or backrefs for the block is cached.
458 *
459 * NOTE: if we find that backrefs for a block are cached, we know backrefs for
460 * all upper level blocks that directly/indirectly reference the block are also
461 * cached.
462 */
463static noinline_for_stack struct btrfs_backref_node *build_backref_tree(
464 struct btrfs_trans_handle *trans,
465 struct reloc_control *rc, struct btrfs_key *node_key,
466 int level, u64 bytenr)
467{
468 struct btrfs_backref_iter *iter;
469 struct btrfs_backref_cache *cache = &rc->backref_cache;
470 /* For searching parent of TREE_BLOCK_REF */
471 struct btrfs_path *path;
472 struct btrfs_backref_node *cur;
473 struct btrfs_backref_node *node = NULL;
474 struct btrfs_backref_edge *edge;
475 int ret;
476 int err = 0;
477
478 iter = btrfs_backref_iter_alloc(rc->extent_root->fs_info);
479 if (!iter)
480 return ERR_PTR(-ENOMEM);
481 path = btrfs_alloc_path();
482 if (!path) {
483 err = -ENOMEM;
484 goto out;
485 }
486
487 node = btrfs_backref_alloc_node(cache, bytenr, level);
488 if (!node) {
489 err = -ENOMEM;
490 goto out;
491 }
492
493 node->lowest = 1;
494 cur = node;
495
496 /* Breadth-first search to build backref cache */
497 do {
498 ret = btrfs_backref_add_tree_node(trans, cache, path, iter,
499 node_key, cur);
500 if (ret < 0) {
501 err = ret;
502 goto out;
503 }
504 edge = list_first_entry_or_null(&cache->pending_edge,
505 struct btrfs_backref_edge, list[UPPER]);
506 /*
507 * The pending list isn't empty, take the first block to
508 * process
509 */
510 if (edge) {
511 list_del_init(&edge->list[UPPER]);
512 cur = edge->node[UPPER];
513 }
514 } while (edge);
515
516 /* Finish the upper linkage of newly added edges/nodes */
517 ret = btrfs_backref_finish_upper_links(cache, node);
518 if (ret < 0) {
519 err = ret;
520 goto out;
521 }
522
523 if (handle_useless_nodes(rc, node))
524 node = NULL;
525out:
526 btrfs_backref_iter_free(iter);
527 btrfs_free_path(path);
528 if (err) {
529 btrfs_backref_error_cleanup(cache, node);
530 return ERR_PTR(err);
531 }
532 ASSERT(!node || !node->detached);
533 ASSERT(list_empty(&cache->useless_node) &&
534 list_empty(&cache->pending_edge));
535 return node;
536}
537
538/*
539 * helper to add backref node for the newly created snapshot.
540 * the backref node is created by cloning backref node that
541 * corresponds to root of source tree
542 */
543static int clone_backref_node(struct btrfs_trans_handle *trans,
544 struct reloc_control *rc,
545 const struct btrfs_root *src,
546 struct btrfs_root *dest)
547{
548 struct btrfs_root *reloc_root = src->reloc_root;
549 struct btrfs_backref_cache *cache = &rc->backref_cache;
550 struct btrfs_backref_node *node = NULL;
551 struct btrfs_backref_node *new_node;
552 struct btrfs_backref_edge *edge;
553 struct btrfs_backref_edge *new_edge;
554 struct rb_node *rb_node;
555
556 if (cache->last_trans > 0)
557 update_backref_cache(trans, cache);
558
559 rb_node = rb_simple_search(&cache->rb_root, src->commit_root->start);
560 if (rb_node) {
561 node = rb_entry(rb_node, struct btrfs_backref_node, rb_node);
562 if (node->detached)
563 node = NULL;
564 else
565 BUG_ON(node->new_bytenr != reloc_root->node->start);
566 }
567
568 if (!node) {
569 rb_node = rb_simple_search(&cache->rb_root,
570 reloc_root->commit_root->start);
571 if (rb_node) {
572 node = rb_entry(rb_node, struct btrfs_backref_node,
573 rb_node);
574 BUG_ON(node->detached);
575 }
576 }
577
578 if (!node)
579 return 0;
580
581 new_node = btrfs_backref_alloc_node(cache, dest->node->start,
582 node->level);
583 if (!new_node)
584 return -ENOMEM;
585
586 new_node->lowest = node->lowest;
587 new_node->checked = 1;
588 new_node->root = btrfs_grab_root(dest);
589 ASSERT(new_node->root);
590
591 if (!node->lowest) {
592 list_for_each_entry(edge, &node->lower, list[UPPER]) {
593 new_edge = btrfs_backref_alloc_edge(cache);
594 if (!new_edge)
595 goto fail;
596
597 btrfs_backref_link_edge(new_edge, edge->node[LOWER],
598 new_node, LINK_UPPER);
599 }
600 } else {
601 list_add_tail(&new_node->lower, &cache->leaves);
602 }
603
604 rb_node = rb_simple_insert(&cache->rb_root, new_node->bytenr,
605 &new_node->rb_node);
606 if (rb_node)
607 btrfs_backref_panic(trans->fs_info, new_node->bytenr, -EEXIST);
608
609 if (!new_node->lowest) {
610 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
611 list_add_tail(&new_edge->list[LOWER],
612 &new_edge->node[LOWER]->upper);
613 }
614 }
615 return 0;
616fail:
617 while (!list_empty(&new_node->lower)) {
618 new_edge = list_entry(new_node->lower.next,
619 struct btrfs_backref_edge, list[UPPER]);
620 list_del(&new_edge->list[UPPER]);
621 btrfs_backref_free_edge(cache, new_edge);
622 }
623 btrfs_backref_free_node(cache, new_node);
624 return -ENOMEM;
625}
626
627/*
628 * helper to add 'address of tree root -> reloc tree' mapping
629 */
630static int __add_reloc_root(struct btrfs_root *root)
631{
632 struct btrfs_fs_info *fs_info = root->fs_info;
633 struct rb_node *rb_node;
634 struct mapping_node *node;
635 struct reloc_control *rc = fs_info->reloc_ctl;
636
637 node = kmalloc(sizeof(*node), GFP_NOFS);
638 if (!node)
639 return -ENOMEM;
640
641 node->bytenr = root->commit_root->start;
642 node->data = root;
643
644 spin_lock(&rc->reloc_root_tree.lock);
645 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
646 node->bytenr, &node->rb_node);
647 spin_unlock(&rc->reloc_root_tree.lock);
648 if (rb_node) {
649 btrfs_err(fs_info,
650 "Duplicate root found for start=%llu while inserting into relocation tree",
651 node->bytenr);
652 return -EEXIST;
653 }
654
655 list_add_tail(&root->root_list, &rc->reloc_roots);
656 return 0;
657}
658
659/*
660 * helper to delete the 'address of tree root -> reloc tree'
661 * mapping
662 */
663static void __del_reloc_root(struct btrfs_root *root)
664{
665 struct btrfs_fs_info *fs_info = root->fs_info;
666 struct rb_node *rb_node;
667 struct mapping_node *node = NULL;
668 struct reloc_control *rc = fs_info->reloc_ctl;
669 bool put_ref = false;
670
671 if (rc && root->node) {
672 spin_lock(&rc->reloc_root_tree.lock);
673 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
674 root->commit_root->start);
675 if (rb_node) {
676 node = rb_entry(rb_node, struct mapping_node, rb_node);
677 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
678 RB_CLEAR_NODE(&node->rb_node);
679 }
680 spin_unlock(&rc->reloc_root_tree.lock);
681 ASSERT(!node || (struct btrfs_root *)node->data == root);
682 }
683
684 /*
685 * We only put the reloc root here if it's on the list. There's a lot
686 * of places where the pattern is to splice the rc->reloc_roots, process
687 * the reloc roots, and then add the reloc root back onto
688 * rc->reloc_roots. If we call __del_reloc_root while it's off of the
689 * list we don't want the reference being dropped, because the guy
690 * messing with the list is in charge of the reference.
691 */
692 spin_lock(&fs_info->trans_lock);
693 if (!list_empty(&root->root_list)) {
694 put_ref = true;
695 list_del_init(&root->root_list);
696 }
697 spin_unlock(&fs_info->trans_lock);
698 if (put_ref)
699 btrfs_put_root(root);
700 kfree(node);
701}
702
703/*
704 * helper to update the 'address of tree root -> reloc tree'
705 * mapping
706 */
707static int __update_reloc_root(struct btrfs_root *root)
708{
709 struct btrfs_fs_info *fs_info = root->fs_info;
710 struct rb_node *rb_node;
711 struct mapping_node *node = NULL;
712 struct reloc_control *rc = fs_info->reloc_ctl;
713
714 spin_lock(&rc->reloc_root_tree.lock);
715 rb_node = rb_simple_search(&rc->reloc_root_tree.rb_root,
716 root->commit_root->start);
717 if (rb_node) {
718 node = rb_entry(rb_node, struct mapping_node, rb_node);
719 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
720 }
721 spin_unlock(&rc->reloc_root_tree.lock);
722
723 if (!node)
724 return 0;
725 BUG_ON((struct btrfs_root *)node->data != root);
726
727 spin_lock(&rc->reloc_root_tree.lock);
728 node->bytenr = root->node->start;
729 rb_node = rb_simple_insert(&rc->reloc_root_tree.rb_root,
730 node->bytenr, &node->rb_node);
731 spin_unlock(&rc->reloc_root_tree.lock);
732 if (rb_node)
733 btrfs_backref_panic(fs_info, node->bytenr, -EEXIST);
734 return 0;
735}
736
737static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
738 struct btrfs_root *root, u64 objectid)
739{
740 struct btrfs_fs_info *fs_info = root->fs_info;
741 struct btrfs_root *reloc_root;
742 struct extent_buffer *eb;
743 struct btrfs_root_item *root_item;
744 struct btrfs_key root_key;
745 int ret = 0;
746 bool must_abort = false;
747
748 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
749 if (!root_item)
750 return ERR_PTR(-ENOMEM);
751
752 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
753 root_key.type = BTRFS_ROOT_ITEM_KEY;
754 root_key.offset = objectid;
755
756 if (root->root_key.objectid == objectid) {
757 u64 commit_root_gen;
758
759 /* called by btrfs_init_reloc_root */
760 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
761 BTRFS_TREE_RELOC_OBJECTID);
762 if (ret)
763 goto fail;
764
765 /*
766 * Set the last_snapshot field to the generation of the commit
767 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
768 * correctly (returns true) when the relocation root is created
769 * either inside the critical section of a transaction commit
770 * (through transaction.c:qgroup_account_snapshot()) and when
771 * it's created before the transaction commit is started.
772 */
773 commit_root_gen = btrfs_header_generation(root->commit_root);
774 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
775 } else {
776 /*
777 * called by btrfs_reloc_post_snapshot_hook.
778 * the source tree is a reloc tree, all tree blocks
779 * modified after it was created have RELOC flag
780 * set in their headers. so it's OK to not update
781 * the 'last_snapshot'.
782 */
783 ret = btrfs_copy_root(trans, root, root->node, &eb,
784 BTRFS_TREE_RELOC_OBJECTID);
785 if (ret)
786 goto fail;
787 }
788
789 /*
790 * We have changed references at this point, we must abort the
791 * transaction if anything fails.
792 */
793 must_abort = true;
794
795 memcpy(root_item, &root->root_item, sizeof(*root_item));
796 btrfs_set_root_bytenr(root_item, eb->start);
797 btrfs_set_root_level(root_item, btrfs_header_level(eb));
798 btrfs_set_root_generation(root_item, trans->transid);
799
800 if (root->root_key.objectid == objectid) {
801 btrfs_set_root_refs(root_item, 0);
802 memset(&root_item->drop_progress, 0,
803 sizeof(struct btrfs_disk_key));
804 btrfs_set_root_drop_level(root_item, 0);
805 }
806
807 btrfs_tree_unlock(eb);
808 free_extent_buffer(eb);
809
810 ret = btrfs_insert_root(trans, fs_info->tree_root,
811 &root_key, root_item);
812 if (ret)
813 goto fail;
814
815 kfree(root_item);
816
817 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
818 if (IS_ERR(reloc_root)) {
819 ret = PTR_ERR(reloc_root);
820 goto abort;
821 }
822 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
823 reloc_root->last_trans = trans->transid;
824 return reloc_root;
825fail:
826 kfree(root_item);
827abort:
828 if (must_abort)
829 btrfs_abort_transaction(trans, ret);
830 return ERR_PTR(ret);
831}
832
833/*
834 * create reloc tree for a given fs tree. reloc tree is just a
835 * snapshot of the fs tree with special root objectid.
836 *
837 * The reloc_root comes out of here with two references, one for
838 * root->reloc_root, and another for being on the rc->reloc_roots list.
839 */
840int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
841 struct btrfs_root *root)
842{
843 struct btrfs_fs_info *fs_info = root->fs_info;
844 struct btrfs_root *reloc_root;
845 struct reloc_control *rc = fs_info->reloc_ctl;
846 struct btrfs_block_rsv *rsv;
847 int clear_rsv = 0;
848 int ret;
849
850 if (!rc)
851 return 0;
852
853 /*
854 * The subvolume has reloc tree but the swap is finished, no need to
855 * create/update the dead reloc tree
856 */
857 if (reloc_root_is_dead(root))
858 return 0;
859
860 /*
861 * This is subtle but important. We do not do
862 * record_root_in_transaction for reloc roots, instead we record their
863 * corresponding fs root, and then here we update the last trans for the
864 * reloc root. This means that we have to do this for the entire life
865 * of the reloc root, regardless of which stage of the relocation we are
866 * in.
867 */
868 if (root->reloc_root) {
869 reloc_root = root->reloc_root;
870 reloc_root->last_trans = trans->transid;
871 return 0;
872 }
873
874 /*
875 * We are merging reloc roots, we do not need new reloc trees. Also
876 * reloc trees never need their own reloc tree.
877 */
878 if (!rc->create_reloc_tree ||
879 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
880 return 0;
881
882 if (!trans->reloc_reserved) {
883 rsv = trans->block_rsv;
884 trans->block_rsv = rc->block_rsv;
885 clear_rsv = 1;
886 }
887 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
888 if (clear_rsv)
889 trans->block_rsv = rsv;
890 if (IS_ERR(reloc_root))
891 return PTR_ERR(reloc_root);
892
893 ret = __add_reloc_root(reloc_root);
894 ASSERT(ret != -EEXIST);
895 if (ret) {
896 /* Pairs with create_reloc_root */
897 btrfs_put_root(reloc_root);
898 return ret;
899 }
900 root->reloc_root = btrfs_grab_root(reloc_root);
901 return 0;
902}
903
904/*
905 * update root item of reloc tree
906 */
907int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
908 struct btrfs_root *root)
909{
910 struct btrfs_fs_info *fs_info = root->fs_info;
911 struct btrfs_root *reloc_root;
912 struct btrfs_root_item *root_item;
913 int ret;
914
915 if (!have_reloc_root(root))
916 return 0;
917
918 reloc_root = root->reloc_root;
919 root_item = &reloc_root->root_item;
920
921 /*
922 * We are probably ok here, but __del_reloc_root() will drop its ref of
923 * the root. We have the ref for root->reloc_root, but just in case
924 * hold it while we update the reloc root.
925 */
926 btrfs_grab_root(reloc_root);
927
928 /* root->reloc_root will stay until current relocation finished */
929 if (fs_info->reloc_ctl->merge_reloc_tree &&
930 btrfs_root_refs(root_item) == 0) {
931 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
932 /*
933 * Mark the tree as dead before we change reloc_root so
934 * have_reloc_root will not touch it from now on.
935 */
936 smp_wmb();
937 __del_reloc_root(reloc_root);
938 }
939
940 if (reloc_root->commit_root != reloc_root->node) {
941 __update_reloc_root(reloc_root);
942 btrfs_set_root_node(root_item, reloc_root->node);
943 free_extent_buffer(reloc_root->commit_root);
944 reloc_root->commit_root = btrfs_root_node(reloc_root);
945 }
946
947 ret = btrfs_update_root(trans, fs_info->tree_root,
948 &reloc_root->root_key, root_item);
949 btrfs_put_root(reloc_root);
950 return ret;
951}
952
953/*
954 * helper to find first cached inode with inode number >= objectid
955 * in a subvolume
956 */
957static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
958{
959 struct rb_node *node;
960 struct rb_node *prev;
961 struct btrfs_inode *entry;
962 struct inode *inode;
963
964 spin_lock(&root->inode_lock);
965again:
966 node = root->inode_tree.rb_node;
967 prev = NULL;
968 while (node) {
969 prev = node;
970 entry = rb_entry(node, struct btrfs_inode, rb_node);
971
972 if (objectid < btrfs_ino(entry))
973 node = node->rb_left;
974 else if (objectid > btrfs_ino(entry))
975 node = node->rb_right;
976 else
977 break;
978 }
979 if (!node) {
980 while (prev) {
981 entry = rb_entry(prev, struct btrfs_inode, rb_node);
982 if (objectid <= btrfs_ino(entry)) {
983 node = prev;
984 break;
985 }
986 prev = rb_next(prev);
987 }
988 }
989 while (node) {
990 entry = rb_entry(node, struct btrfs_inode, rb_node);
991 inode = igrab(&entry->vfs_inode);
992 if (inode) {
993 spin_unlock(&root->inode_lock);
994 return inode;
995 }
996
997 objectid = btrfs_ino(entry) + 1;
998 if (cond_resched_lock(&root->inode_lock))
999 goto again;
1000
1001 node = rb_next(node);
1002 }
1003 spin_unlock(&root->inode_lock);
1004 return NULL;
1005}
1006
1007/*
1008 * get new location of data
1009 */
1010static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1011 u64 bytenr, u64 num_bytes)
1012{
1013 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1014 struct btrfs_path *path;
1015 struct btrfs_file_extent_item *fi;
1016 struct extent_buffer *leaf;
1017 int ret;
1018
1019 path = btrfs_alloc_path();
1020 if (!path)
1021 return -ENOMEM;
1022
1023 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1024 ret = btrfs_lookup_file_extent(NULL, root, path,
1025 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1026 if (ret < 0)
1027 goto out;
1028 if (ret > 0) {
1029 ret = -ENOENT;
1030 goto out;
1031 }
1032
1033 leaf = path->nodes[0];
1034 fi = btrfs_item_ptr(leaf, path->slots[0],
1035 struct btrfs_file_extent_item);
1036
1037 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1038 btrfs_file_extent_compression(leaf, fi) ||
1039 btrfs_file_extent_encryption(leaf, fi) ||
1040 btrfs_file_extent_other_encoding(leaf, fi));
1041
1042 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1043 ret = -EINVAL;
1044 goto out;
1045 }
1046
1047 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1048 ret = 0;
1049out:
1050 btrfs_free_path(path);
1051 return ret;
1052}
1053
1054/*
1055 * update file extent items in the tree leaf to point to
1056 * the new locations.
1057 */
1058static noinline_for_stack
1059int replace_file_extents(struct btrfs_trans_handle *trans,
1060 struct reloc_control *rc,
1061 struct btrfs_root *root,
1062 struct extent_buffer *leaf)
1063{
1064 struct btrfs_fs_info *fs_info = root->fs_info;
1065 struct btrfs_key key;
1066 struct btrfs_file_extent_item *fi;
1067 struct inode *inode = NULL;
1068 u64 parent;
1069 u64 bytenr;
1070 u64 new_bytenr = 0;
1071 u64 num_bytes;
1072 u64 end;
1073 u32 nritems;
1074 u32 i;
1075 int ret = 0;
1076 int first = 1;
1077 int dirty = 0;
1078
1079 if (rc->stage != UPDATE_DATA_PTRS)
1080 return 0;
1081
1082 /* reloc trees always use full backref */
1083 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1084 parent = leaf->start;
1085 else
1086 parent = 0;
1087
1088 nritems = btrfs_header_nritems(leaf);
1089 for (i = 0; i < nritems; i++) {
1090 struct btrfs_ref ref = { 0 };
1091
1092 cond_resched();
1093 btrfs_item_key_to_cpu(leaf, &key, i);
1094 if (key.type != BTRFS_EXTENT_DATA_KEY)
1095 continue;
1096 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1097 if (btrfs_file_extent_type(leaf, fi) ==
1098 BTRFS_FILE_EXTENT_INLINE)
1099 continue;
1100 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1101 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1102 if (bytenr == 0)
1103 continue;
1104 if (!in_range(bytenr, rc->block_group->start,
1105 rc->block_group->length))
1106 continue;
1107
1108 /*
1109 * if we are modifying block in fs tree, wait for read_folio
1110 * to complete and drop the extent cache
1111 */
1112 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1113 if (first) {
1114 inode = find_next_inode(root, key.objectid);
1115 first = 0;
1116 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1117 btrfs_add_delayed_iput(BTRFS_I(inode));
1118 inode = find_next_inode(root, key.objectid);
1119 }
1120 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1121 struct extent_state *cached_state = NULL;
1122
1123 end = key.offset +
1124 btrfs_file_extent_num_bytes(leaf, fi);
1125 WARN_ON(!IS_ALIGNED(key.offset,
1126 fs_info->sectorsize));
1127 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1128 end--;
1129 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1130 key.offset, end,
1131 &cached_state);
1132 if (!ret)
1133 continue;
1134
1135 btrfs_drop_extent_map_range(BTRFS_I(inode),
1136 key.offset, end, true);
1137 unlock_extent(&BTRFS_I(inode)->io_tree,
1138 key.offset, end, &cached_state);
1139 }
1140 }
1141
1142 ret = get_new_location(rc->data_inode, &new_bytenr,
1143 bytenr, num_bytes);
1144 if (ret) {
1145 /*
1146 * Don't have to abort since we've not changed anything
1147 * in the file extent yet.
1148 */
1149 break;
1150 }
1151
1152 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1153 dirty = 1;
1154
1155 key.offset -= btrfs_file_extent_offset(leaf, fi);
1156 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1157 num_bytes, parent, root->root_key.objectid);
1158 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1159 key.objectid, key.offset,
1160 root->root_key.objectid, false);
1161 ret = btrfs_inc_extent_ref(trans, &ref);
1162 if (ret) {
1163 btrfs_abort_transaction(trans, ret);
1164 break;
1165 }
1166
1167 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1168 num_bytes, parent, root->root_key.objectid);
1169 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1170 key.objectid, key.offset,
1171 root->root_key.objectid, false);
1172 ret = btrfs_free_extent(trans, &ref);
1173 if (ret) {
1174 btrfs_abort_transaction(trans, ret);
1175 break;
1176 }
1177 }
1178 if (dirty)
1179 btrfs_mark_buffer_dirty(trans, leaf);
1180 if (inode)
1181 btrfs_add_delayed_iput(BTRFS_I(inode));
1182 return ret;
1183}
1184
1185static noinline_for_stack int memcmp_node_keys(const struct extent_buffer *eb,
1186 int slot, const struct btrfs_path *path,
1187 int level)
1188{
1189 struct btrfs_disk_key key1;
1190 struct btrfs_disk_key key2;
1191 btrfs_node_key(eb, &key1, slot);
1192 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1193 return memcmp(&key1, &key2, sizeof(key1));
1194}
1195
1196/*
1197 * try to replace tree blocks in fs tree with the new blocks
1198 * in reloc tree. tree blocks haven't been modified since the
1199 * reloc tree was create can be replaced.
1200 *
1201 * if a block was replaced, level of the block + 1 is returned.
1202 * if no block got replaced, 0 is returned. if there are other
1203 * errors, a negative error number is returned.
1204 */
1205static noinline_for_stack
1206int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1207 struct btrfs_root *dest, struct btrfs_root *src,
1208 struct btrfs_path *path, struct btrfs_key *next_key,
1209 int lowest_level, int max_level)
1210{
1211 struct btrfs_fs_info *fs_info = dest->fs_info;
1212 struct extent_buffer *eb;
1213 struct extent_buffer *parent;
1214 struct btrfs_ref ref = { 0 };
1215 struct btrfs_key key;
1216 u64 old_bytenr;
1217 u64 new_bytenr;
1218 u64 old_ptr_gen;
1219 u64 new_ptr_gen;
1220 u64 last_snapshot;
1221 u32 blocksize;
1222 int cow = 0;
1223 int level;
1224 int ret;
1225 int slot;
1226
1227 ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1228 ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1229
1230 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1231again:
1232 slot = path->slots[lowest_level];
1233 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1234
1235 eb = btrfs_lock_root_node(dest);
1236 level = btrfs_header_level(eb);
1237
1238 if (level < lowest_level) {
1239 btrfs_tree_unlock(eb);
1240 free_extent_buffer(eb);
1241 return 0;
1242 }
1243
1244 if (cow) {
1245 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb,
1246 BTRFS_NESTING_COW);
1247 if (ret) {
1248 btrfs_tree_unlock(eb);
1249 free_extent_buffer(eb);
1250 return ret;
1251 }
1252 }
1253
1254 if (next_key) {
1255 next_key->objectid = (u64)-1;
1256 next_key->type = (u8)-1;
1257 next_key->offset = (u64)-1;
1258 }
1259
1260 parent = eb;
1261 while (1) {
1262 level = btrfs_header_level(parent);
1263 ASSERT(level >= lowest_level);
1264
1265 ret = btrfs_bin_search(parent, 0, &key, &slot);
1266 if (ret < 0)
1267 break;
1268 if (ret && slot > 0)
1269 slot--;
1270
1271 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1272 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1273
1274 old_bytenr = btrfs_node_blockptr(parent, slot);
1275 blocksize = fs_info->nodesize;
1276 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1277
1278 if (level <= max_level) {
1279 eb = path->nodes[level];
1280 new_bytenr = btrfs_node_blockptr(eb,
1281 path->slots[level]);
1282 new_ptr_gen = btrfs_node_ptr_generation(eb,
1283 path->slots[level]);
1284 } else {
1285 new_bytenr = 0;
1286 new_ptr_gen = 0;
1287 }
1288
1289 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1290 ret = level;
1291 break;
1292 }
1293
1294 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1295 memcmp_node_keys(parent, slot, path, level)) {
1296 if (level <= lowest_level) {
1297 ret = 0;
1298 break;
1299 }
1300
1301 eb = btrfs_read_node_slot(parent, slot);
1302 if (IS_ERR(eb)) {
1303 ret = PTR_ERR(eb);
1304 break;
1305 }
1306 btrfs_tree_lock(eb);
1307 if (cow) {
1308 ret = btrfs_cow_block(trans, dest, eb, parent,
1309 slot, &eb,
1310 BTRFS_NESTING_COW);
1311 if (ret) {
1312 btrfs_tree_unlock(eb);
1313 free_extent_buffer(eb);
1314 break;
1315 }
1316 }
1317
1318 btrfs_tree_unlock(parent);
1319 free_extent_buffer(parent);
1320
1321 parent = eb;
1322 continue;
1323 }
1324
1325 if (!cow) {
1326 btrfs_tree_unlock(parent);
1327 free_extent_buffer(parent);
1328 cow = 1;
1329 goto again;
1330 }
1331
1332 btrfs_node_key_to_cpu(path->nodes[level], &key,
1333 path->slots[level]);
1334 btrfs_release_path(path);
1335
1336 path->lowest_level = level;
1337 set_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1338 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1339 clear_bit(BTRFS_ROOT_RESET_LOCKDEP_CLASS, &src->state);
1340 path->lowest_level = 0;
1341 if (ret) {
1342 if (ret > 0)
1343 ret = -ENOENT;
1344 break;
1345 }
1346
1347 /*
1348 * Info qgroup to trace both subtrees.
1349 *
1350 * We must trace both trees.
1351 * 1) Tree reloc subtree
1352 * If not traced, we will leak data numbers
1353 * 2) Fs subtree
1354 * If not traced, we will double count old data
1355 *
1356 * We don't scan the subtree right now, but only record
1357 * the swapped tree blocks.
1358 * The real subtree rescan is delayed until we have new
1359 * CoW on the subtree root node before transaction commit.
1360 */
1361 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1362 rc->block_group, parent, slot,
1363 path->nodes[level], path->slots[level],
1364 last_snapshot);
1365 if (ret < 0)
1366 break;
1367 /*
1368 * swap blocks in fs tree and reloc tree.
1369 */
1370 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1371 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1372 btrfs_mark_buffer_dirty(trans, parent);
1373
1374 btrfs_set_node_blockptr(path->nodes[level],
1375 path->slots[level], old_bytenr);
1376 btrfs_set_node_ptr_generation(path->nodes[level],
1377 path->slots[level], old_ptr_gen);
1378 btrfs_mark_buffer_dirty(trans, path->nodes[level]);
1379
1380 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1381 blocksize, path->nodes[level]->start,
1382 src->root_key.objectid);
1383 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1384 0, true);
1385 ret = btrfs_inc_extent_ref(trans, &ref);
1386 if (ret) {
1387 btrfs_abort_transaction(trans, ret);
1388 break;
1389 }
1390 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1391 blocksize, 0, dest->root_key.objectid);
1392 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid, 0,
1393 true);
1394 ret = btrfs_inc_extent_ref(trans, &ref);
1395 if (ret) {
1396 btrfs_abort_transaction(trans, ret);
1397 break;
1398 }
1399
1400 /* We don't know the real owning_root, use 0. */
1401 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1402 blocksize, path->nodes[level]->start, 0);
1403 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid,
1404 0, true);
1405 ret = btrfs_free_extent(trans, &ref);
1406 if (ret) {
1407 btrfs_abort_transaction(trans, ret);
1408 break;
1409 }
1410
1411 /* We don't know the real owning_root, use 0. */
1412 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1413 blocksize, 0, 0);
1414 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid,
1415 0, true);
1416 ret = btrfs_free_extent(trans, &ref);
1417 if (ret) {
1418 btrfs_abort_transaction(trans, ret);
1419 break;
1420 }
1421
1422 btrfs_unlock_up_safe(path, 0);
1423
1424 ret = level;
1425 break;
1426 }
1427 btrfs_tree_unlock(parent);
1428 free_extent_buffer(parent);
1429 return ret;
1430}
1431
1432/*
1433 * helper to find next relocated block in reloc tree
1434 */
1435static noinline_for_stack
1436int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1437 int *level)
1438{
1439 struct extent_buffer *eb;
1440 int i;
1441 u64 last_snapshot;
1442 u32 nritems;
1443
1444 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1445
1446 for (i = 0; i < *level; i++) {
1447 free_extent_buffer(path->nodes[i]);
1448 path->nodes[i] = NULL;
1449 }
1450
1451 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1452 eb = path->nodes[i];
1453 nritems = btrfs_header_nritems(eb);
1454 while (path->slots[i] + 1 < nritems) {
1455 path->slots[i]++;
1456 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1457 last_snapshot)
1458 continue;
1459
1460 *level = i;
1461 return 0;
1462 }
1463 free_extent_buffer(path->nodes[i]);
1464 path->nodes[i] = NULL;
1465 }
1466 return 1;
1467}
1468
1469/*
1470 * walk down reloc tree to find relocated block of lowest level
1471 */
1472static noinline_for_stack
1473int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1474 int *level)
1475{
1476 struct extent_buffer *eb = NULL;
1477 int i;
1478 u64 ptr_gen = 0;
1479 u64 last_snapshot;
1480 u32 nritems;
1481
1482 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1483
1484 for (i = *level; i > 0; i--) {
1485 eb = path->nodes[i];
1486 nritems = btrfs_header_nritems(eb);
1487 while (path->slots[i] < nritems) {
1488 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
1489 if (ptr_gen > last_snapshot)
1490 break;
1491 path->slots[i]++;
1492 }
1493 if (path->slots[i] >= nritems) {
1494 if (i == *level)
1495 break;
1496 *level = i + 1;
1497 return 0;
1498 }
1499 if (i == 1) {
1500 *level = i;
1501 return 0;
1502 }
1503
1504 eb = btrfs_read_node_slot(eb, path->slots[i]);
1505 if (IS_ERR(eb))
1506 return PTR_ERR(eb);
1507 BUG_ON(btrfs_header_level(eb) != i - 1);
1508 path->nodes[i - 1] = eb;
1509 path->slots[i - 1] = 0;
1510 }
1511 return 1;
1512}
1513
1514/*
1515 * invalidate extent cache for file extents whose key in range of
1516 * [min_key, max_key)
1517 */
1518static int invalidate_extent_cache(struct btrfs_root *root,
1519 const struct btrfs_key *min_key,
1520 const struct btrfs_key *max_key)
1521{
1522 struct btrfs_fs_info *fs_info = root->fs_info;
1523 struct inode *inode = NULL;
1524 u64 objectid;
1525 u64 start, end;
1526 u64 ino;
1527
1528 objectid = min_key->objectid;
1529 while (1) {
1530 struct extent_state *cached_state = NULL;
1531
1532 cond_resched();
1533 iput(inode);
1534
1535 if (objectid > max_key->objectid)
1536 break;
1537
1538 inode = find_next_inode(root, objectid);
1539 if (!inode)
1540 break;
1541 ino = btrfs_ino(BTRFS_I(inode));
1542
1543 if (ino > max_key->objectid) {
1544 iput(inode);
1545 break;
1546 }
1547
1548 objectid = ino + 1;
1549 if (!S_ISREG(inode->i_mode))
1550 continue;
1551
1552 if (unlikely(min_key->objectid == ino)) {
1553 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
1554 continue;
1555 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
1556 start = 0;
1557 else {
1558 start = min_key->offset;
1559 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
1560 }
1561 } else {
1562 start = 0;
1563 }
1564
1565 if (unlikely(max_key->objectid == ino)) {
1566 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
1567 continue;
1568 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
1569 end = (u64)-1;
1570 } else {
1571 if (max_key->offset == 0)
1572 continue;
1573 end = max_key->offset;
1574 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1575 end--;
1576 }
1577 } else {
1578 end = (u64)-1;
1579 }
1580
1581 /* the lock_extent waits for read_folio to complete */
1582 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1583 btrfs_drop_extent_map_range(BTRFS_I(inode), start, end, true);
1584 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
1585 }
1586 return 0;
1587}
1588
1589static int find_next_key(struct btrfs_path *path, int level,
1590 struct btrfs_key *key)
1591
1592{
1593 while (level < BTRFS_MAX_LEVEL) {
1594 if (!path->nodes[level])
1595 break;
1596 if (path->slots[level] + 1 <
1597 btrfs_header_nritems(path->nodes[level])) {
1598 btrfs_node_key_to_cpu(path->nodes[level], key,
1599 path->slots[level] + 1);
1600 return 0;
1601 }
1602 level++;
1603 }
1604 return 1;
1605}
1606
1607/*
1608 * Insert current subvolume into reloc_control::dirty_subvol_roots
1609 */
1610static int insert_dirty_subvol(struct btrfs_trans_handle *trans,
1611 struct reloc_control *rc,
1612 struct btrfs_root *root)
1613{
1614 struct btrfs_root *reloc_root = root->reloc_root;
1615 struct btrfs_root_item *reloc_root_item;
1616 int ret;
1617
1618 /* @root must be a subvolume tree root with a valid reloc tree */
1619 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1620 ASSERT(reloc_root);
1621
1622 reloc_root_item = &reloc_root->root_item;
1623 memset(&reloc_root_item->drop_progress, 0,
1624 sizeof(reloc_root_item->drop_progress));
1625 btrfs_set_root_drop_level(reloc_root_item, 0);
1626 btrfs_set_root_refs(reloc_root_item, 0);
1627 ret = btrfs_update_reloc_root(trans, root);
1628 if (ret)
1629 return ret;
1630
1631 if (list_empty(&root->reloc_dirty_list)) {
1632 btrfs_grab_root(root);
1633 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
1634 }
1635
1636 return 0;
1637}
1638
1639static int clean_dirty_subvols(struct reloc_control *rc)
1640{
1641 struct btrfs_root *root;
1642 struct btrfs_root *next;
1643 int ret = 0;
1644 int ret2;
1645
1646 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
1647 reloc_dirty_list) {
1648 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1649 /* Merged subvolume, cleanup its reloc root */
1650 struct btrfs_root *reloc_root = root->reloc_root;
1651
1652 list_del_init(&root->reloc_dirty_list);
1653 root->reloc_root = NULL;
1654 /*
1655 * Need barrier to ensure clear_bit() only happens after
1656 * root->reloc_root = NULL. Pairs with have_reloc_root.
1657 */
1658 smp_wmb();
1659 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1660 if (reloc_root) {
1661 /*
1662 * btrfs_drop_snapshot drops our ref we hold for
1663 * ->reloc_root. If it fails however we must
1664 * drop the ref ourselves.
1665 */
1666 ret2 = btrfs_drop_snapshot(reloc_root, 0, 1);
1667 if (ret2 < 0) {
1668 btrfs_put_root(reloc_root);
1669 if (!ret)
1670 ret = ret2;
1671 }
1672 }
1673 btrfs_put_root(root);
1674 } else {
1675 /* Orphan reloc tree, just clean it up */
1676 ret2 = btrfs_drop_snapshot(root, 0, 1);
1677 if (ret2 < 0) {
1678 btrfs_put_root(root);
1679 if (!ret)
1680 ret = ret2;
1681 }
1682 }
1683 }
1684 return ret;
1685}
1686
1687/*
1688 * merge the relocated tree blocks in reloc tree with corresponding
1689 * fs tree.
1690 */
1691static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
1692 struct btrfs_root *root)
1693{
1694 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1695 struct btrfs_key key;
1696 struct btrfs_key next_key;
1697 struct btrfs_trans_handle *trans = NULL;
1698 struct btrfs_root *reloc_root;
1699 struct btrfs_root_item *root_item;
1700 struct btrfs_path *path;
1701 struct extent_buffer *leaf;
1702 int reserve_level;
1703 int level;
1704 int max_level;
1705 int replaced = 0;
1706 int ret = 0;
1707 u32 min_reserved;
1708
1709 path = btrfs_alloc_path();
1710 if (!path)
1711 return -ENOMEM;
1712 path->reada = READA_FORWARD;
1713
1714 reloc_root = root->reloc_root;
1715 root_item = &reloc_root->root_item;
1716
1717 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
1718 level = btrfs_root_level(root_item);
1719 atomic_inc(&reloc_root->node->refs);
1720 path->nodes[level] = reloc_root->node;
1721 path->slots[level] = 0;
1722 } else {
1723 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
1724
1725 level = btrfs_root_drop_level(root_item);
1726 BUG_ON(level == 0);
1727 path->lowest_level = level;
1728 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
1729 path->lowest_level = 0;
1730 if (ret < 0) {
1731 btrfs_free_path(path);
1732 return ret;
1733 }
1734
1735 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
1736 path->slots[level]);
1737 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
1738
1739 btrfs_unlock_up_safe(path, 0);
1740 }
1741
1742 /*
1743 * In merge_reloc_root(), we modify the upper level pointer to swap the
1744 * tree blocks between reloc tree and subvolume tree. Thus for tree
1745 * block COW, we COW at most from level 1 to root level for each tree.
1746 *
1747 * Thus the needed metadata size is at most root_level * nodesize,
1748 * and * 2 since we have two trees to COW.
1749 */
1750 reserve_level = max_t(int, 1, btrfs_root_level(root_item));
1751 min_reserved = fs_info->nodesize * reserve_level * 2;
1752 memset(&next_key, 0, sizeof(next_key));
1753
1754 while (1) {
1755 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
1756 min_reserved,
1757 BTRFS_RESERVE_FLUSH_LIMIT);
1758 if (ret)
1759 goto out;
1760 trans = btrfs_start_transaction(root, 0);
1761 if (IS_ERR(trans)) {
1762 ret = PTR_ERR(trans);
1763 trans = NULL;
1764 goto out;
1765 }
1766
1767 /*
1768 * At this point we no longer have a reloc_control, so we can't
1769 * depend on btrfs_init_reloc_root to update our last_trans.
1770 *
1771 * But that's ok, we started the trans handle on our
1772 * corresponding fs_root, which means it's been added to the
1773 * dirty list. At commit time we'll still call
1774 * btrfs_update_reloc_root() and update our root item
1775 * appropriately.
1776 */
1777 reloc_root->last_trans = trans->transid;
1778 trans->block_rsv = rc->block_rsv;
1779
1780 replaced = 0;
1781 max_level = level;
1782
1783 ret = walk_down_reloc_tree(reloc_root, path, &level);
1784 if (ret < 0)
1785 goto out;
1786 if (ret > 0)
1787 break;
1788
1789 if (!find_next_key(path, level, &key) &&
1790 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
1791 ret = 0;
1792 } else {
1793 ret = replace_path(trans, rc, root, reloc_root, path,
1794 &next_key, level, max_level);
1795 }
1796 if (ret < 0)
1797 goto out;
1798 if (ret > 0) {
1799 level = ret;
1800 btrfs_node_key_to_cpu(path->nodes[level], &key,
1801 path->slots[level]);
1802 replaced = 1;
1803 }
1804
1805 ret = walk_up_reloc_tree(reloc_root, path, &level);
1806 if (ret > 0)
1807 break;
1808
1809 BUG_ON(level == 0);
1810 /*
1811 * save the merging progress in the drop_progress.
1812 * this is OK since root refs == 1 in this case.
1813 */
1814 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
1815 path->slots[level]);
1816 btrfs_set_root_drop_level(root_item, level);
1817
1818 btrfs_end_transaction_throttle(trans);
1819 trans = NULL;
1820
1821 btrfs_btree_balance_dirty(fs_info);
1822
1823 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1824 invalidate_extent_cache(root, &key, &next_key);
1825 }
1826
1827 /*
1828 * handle the case only one block in the fs tree need to be
1829 * relocated and the block is tree root.
1830 */
1831 leaf = btrfs_lock_root_node(root);
1832 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf,
1833 BTRFS_NESTING_COW);
1834 btrfs_tree_unlock(leaf);
1835 free_extent_buffer(leaf);
1836out:
1837 btrfs_free_path(path);
1838
1839 if (ret == 0) {
1840 ret = insert_dirty_subvol(trans, rc, root);
1841 if (ret)
1842 btrfs_abort_transaction(trans, ret);
1843 }
1844
1845 if (trans)
1846 btrfs_end_transaction_throttle(trans);
1847
1848 btrfs_btree_balance_dirty(fs_info);
1849
1850 if (replaced && rc->stage == UPDATE_DATA_PTRS)
1851 invalidate_extent_cache(root, &key, &next_key);
1852
1853 return ret;
1854}
1855
1856static noinline_for_stack
1857int prepare_to_merge(struct reloc_control *rc, int err)
1858{
1859 struct btrfs_root *root = rc->extent_root;
1860 struct btrfs_fs_info *fs_info = root->fs_info;
1861 struct btrfs_root *reloc_root;
1862 struct btrfs_trans_handle *trans;
1863 LIST_HEAD(reloc_roots);
1864 u64 num_bytes = 0;
1865 int ret;
1866
1867 mutex_lock(&fs_info->reloc_mutex);
1868 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
1869 rc->merging_rsv_size += rc->nodes_relocated * 2;
1870 mutex_unlock(&fs_info->reloc_mutex);
1871
1872again:
1873 if (!err) {
1874 num_bytes = rc->merging_rsv_size;
1875 ret = btrfs_block_rsv_add(fs_info, rc->block_rsv, num_bytes,
1876 BTRFS_RESERVE_FLUSH_ALL);
1877 if (ret)
1878 err = ret;
1879 }
1880
1881 trans = btrfs_join_transaction(rc->extent_root);
1882 if (IS_ERR(trans)) {
1883 if (!err)
1884 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1885 num_bytes, NULL);
1886 return PTR_ERR(trans);
1887 }
1888
1889 if (!err) {
1890 if (num_bytes != rc->merging_rsv_size) {
1891 btrfs_end_transaction(trans);
1892 btrfs_block_rsv_release(fs_info, rc->block_rsv,
1893 num_bytes, NULL);
1894 goto again;
1895 }
1896 }
1897
1898 rc->merge_reloc_tree = true;
1899
1900 while (!list_empty(&rc->reloc_roots)) {
1901 reloc_root = list_entry(rc->reloc_roots.next,
1902 struct btrfs_root, root_list);
1903 list_del_init(&reloc_root->root_list);
1904
1905 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
1906 false);
1907 if (IS_ERR(root)) {
1908 /*
1909 * Even if we have an error we need this reloc root
1910 * back on our list so we can clean up properly.
1911 */
1912 list_add(&reloc_root->root_list, &reloc_roots);
1913 btrfs_abort_transaction(trans, (int)PTR_ERR(root));
1914 if (!err)
1915 err = PTR_ERR(root);
1916 break;
1917 }
1918
1919 if (unlikely(root->reloc_root != reloc_root)) {
1920 if (root->reloc_root) {
1921 btrfs_err(fs_info,
1922"reloc tree mismatch, root %lld has reloc root key (%lld %u %llu) gen %llu, expect reloc root key (%lld %u %llu) gen %llu",
1923 root->root_key.objectid,
1924 root->reloc_root->root_key.objectid,
1925 root->reloc_root->root_key.type,
1926 root->reloc_root->root_key.offset,
1927 btrfs_root_generation(
1928 &root->reloc_root->root_item),
1929 reloc_root->root_key.objectid,
1930 reloc_root->root_key.type,
1931 reloc_root->root_key.offset,
1932 btrfs_root_generation(
1933 &reloc_root->root_item));
1934 } else {
1935 btrfs_err(fs_info,
1936"reloc tree mismatch, root %lld has no reloc root, expect reloc root key (%lld %u %llu) gen %llu",
1937 root->root_key.objectid,
1938 reloc_root->root_key.objectid,
1939 reloc_root->root_key.type,
1940 reloc_root->root_key.offset,
1941 btrfs_root_generation(
1942 &reloc_root->root_item));
1943 }
1944 list_add(&reloc_root->root_list, &reloc_roots);
1945 btrfs_put_root(root);
1946 btrfs_abort_transaction(trans, -EUCLEAN);
1947 if (!err)
1948 err = -EUCLEAN;
1949 break;
1950 }
1951
1952 /*
1953 * set reference count to 1, so btrfs_recover_relocation
1954 * knows it should resumes merging
1955 */
1956 if (!err)
1957 btrfs_set_root_refs(&reloc_root->root_item, 1);
1958 ret = btrfs_update_reloc_root(trans, root);
1959
1960 /*
1961 * Even if we have an error we need this reloc root back on our
1962 * list so we can clean up properly.
1963 */
1964 list_add(&reloc_root->root_list, &reloc_roots);
1965 btrfs_put_root(root);
1966
1967 if (ret) {
1968 btrfs_abort_transaction(trans, ret);
1969 if (!err)
1970 err = ret;
1971 break;
1972 }
1973 }
1974
1975 list_splice(&reloc_roots, &rc->reloc_roots);
1976
1977 if (!err)
1978 err = btrfs_commit_transaction(trans);
1979 else
1980 btrfs_end_transaction(trans);
1981 return err;
1982}
1983
1984static noinline_for_stack
1985void free_reloc_roots(struct list_head *list)
1986{
1987 struct btrfs_root *reloc_root, *tmp;
1988
1989 list_for_each_entry_safe(reloc_root, tmp, list, root_list)
1990 __del_reloc_root(reloc_root);
1991}
1992
1993static noinline_for_stack
1994void merge_reloc_roots(struct reloc_control *rc)
1995{
1996 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
1997 struct btrfs_root *root;
1998 struct btrfs_root *reloc_root;
1999 LIST_HEAD(reloc_roots);
2000 int found = 0;
2001 int ret = 0;
2002again:
2003 root = rc->extent_root;
2004
2005 /*
2006 * this serializes us with btrfs_record_root_in_transaction,
2007 * we have to make sure nobody is in the middle of
2008 * adding their roots to the list while we are
2009 * doing this splice
2010 */
2011 mutex_lock(&fs_info->reloc_mutex);
2012 list_splice_init(&rc->reloc_roots, &reloc_roots);
2013 mutex_unlock(&fs_info->reloc_mutex);
2014
2015 while (!list_empty(&reloc_roots)) {
2016 found = 1;
2017 reloc_root = list_entry(reloc_roots.next,
2018 struct btrfs_root, root_list);
2019
2020 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
2021 false);
2022 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2023 if (WARN_ON(IS_ERR(root))) {
2024 /*
2025 * For recovery we read the fs roots on mount,
2026 * and if we didn't find the root then we marked
2027 * the reloc root as a garbage root. For normal
2028 * relocation obviously the root should exist in
2029 * memory. However there's no reason we can't
2030 * handle the error properly here just in case.
2031 */
2032 ret = PTR_ERR(root);
2033 goto out;
2034 }
2035 if (WARN_ON(root->reloc_root != reloc_root)) {
2036 /*
2037 * This can happen if on-disk metadata has some
2038 * corruption, e.g. bad reloc tree key offset.
2039 */
2040 ret = -EINVAL;
2041 goto out;
2042 }
2043 ret = merge_reloc_root(rc, root);
2044 btrfs_put_root(root);
2045 if (ret) {
2046 if (list_empty(&reloc_root->root_list))
2047 list_add_tail(&reloc_root->root_list,
2048 &reloc_roots);
2049 goto out;
2050 }
2051 } else {
2052 if (!IS_ERR(root)) {
2053 if (root->reloc_root == reloc_root) {
2054 root->reloc_root = NULL;
2055 btrfs_put_root(reloc_root);
2056 }
2057 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE,
2058 &root->state);
2059 btrfs_put_root(root);
2060 }
2061
2062 list_del_init(&reloc_root->root_list);
2063 /* Don't forget to queue this reloc root for cleanup */
2064 list_add_tail(&reloc_root->reloc_dirty_list,
2065 &rc->dirty_subvol_roots);
2066 }
2067 }
2068
2069 if (found) {
2070 found = 0;
2071 goto again;
2072 }
2073out:
2074 if (ret) {
2075 btrfs_handle_fs_error(fs_info, ret, NULL);
2076 free_reloc_roots(&reloc_roots);
2077
2078 /* new reloc root may be added */
2079 mutex_lock(&fs_info->reloc_mutex);
2080 list_splice_init(&rc->reloc_roots, &reloc_roots);
2081 mutex_unlock(&fs_info->reloc_mutex);
2082 free_reloc_roots(&reloc_roots);
2083 }
2084
2085 /*
2086 * We used to have
2087 *
2088 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2089 *
2090 * here, but it's wrong. If we fail to start the transaction in
2091 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
2092 * have actually been removed from the reloc_root_tree rb tree. This is
2093 * fine because we're bailing here, and we hold a reference on the root
2094 * for the list that holds it, so these roots will be cleaned up when we
2095 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
2096 * will be cleaned up on unmount.
2097 *
2098 * The remaining nodes will be cleaned up by free_reloc_control.
2099 */
2100}
2101
2102static void free_block_list(struct rb_root *blocks)
2103{
2104 struct tree_block *block;
2105 struct rb_node *rb_node;
2106 while ((rb_node = rb_first(blocks))) {
2107 block = rb_entry(rb_node, struct tree_block, rb_node);
2108 rb_erase(rb_node, blocks);
2109 kfree(block);
2110 }
2111}
2112
2113static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2114 struct btrfs_root *reloc_root)
2115{
2116 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2117 struct btrfs_root *root;
2118 int ret;
2119
2120 if (reloc_root->last_trans == trans->transid)
2121 return 0;
2122
2123 root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset, false);
2124
2125 /*
2126 * This should succeed, since we can't have a reloc root without having
2127 * already looked up the actual root and created the reloc root for this
2128 * root.
2129 *
2130 * However if there's some sort of corruption where we have a ref to a
2131 * reloc root without a corresponding root this could return ENOENT.
2132 */
2133 if (IS_ERR(root)) {
2134 ASSERT(0);
2135 return PTR_ERR(root);
2136 }
2137 if (root->reloc_root != reloc_root) {
2138 ASSERT(0);
2139 btrfs_err(fs_info,
2140 "root %llu has two reloc roots associated with it",
2141 reloc_root->root_key.offset);
2142 btrfs_put_root(root);
2143 return -EUCLEAN;
2144 }
2145 ret = btrfs_record_root_in_trans(trans, root);
2146 btrfs_put_root(root);
2147
2148 return ret;
2149}
2150
2151static noinline_for_stack
2152struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2153 struct reloc_control *rc,
2154 struct btrfs_backref_node *node,
2155 struct btrfs_backref_edge *edges[])
2156{
2157 struct btrfs_backref_node *next;
2158 struct btrfs_root *root;
2159 int index = 0;
2160 int ret;
2161
2162 next = node;
2163 while (1) {
2164 cond_resched();
2165 next = walk_up_backref(next, edges, &index);
2166 root = next->root;
2167
2168 /*
2169 * If there is no root, then our references for this block are
2170 * incomplete, as we should be able to walk all the way up to a
2171 * block that is owned by a root.
2172 *
2173 * This path is only for SHAREABLE roots, so if we come upon a
2174 * non-SHAREABLE root then we have backrefs that resolve
2175 * improperly.
2176 *
2177 * Both of these cases indicate file system corruption, or a bug
2178 * in the backref walking code.
2179 */
2180 if (!root) {
2181 ASSERT(0);
2182 btrfs_err(trans->fs_info,
2183 "bytenr %llu doesn't have a backref path ending in a root",
2184 node->bytenr);
2185 return ERR_PTR(-EUCLEAN);
2186 }
2187 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2188 ASSERT(0);
2189 btrfs_err(trans->fs_info,
2190 "bytenr %llu has multiple refs with one ending in a non-shareable root",
2191 node->bytenr);
2192 return ERR_PTR(-EUCLEAN);
2193 }
2194
2195 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2196 ret = record_reloc_root_in_trans(trans, root);
2197 if (ret)
2198 return ERR_PTR(ret);
2199 break;
2200 }
2201
2202 ret = btrfs_record_root_in_trans(trans, root);
2203 if (ret)
2204 return ERR_PTR(ret);
2205 root = root->reloc_root;
2206
2207 /*
2208 * We could have raced with another thread which failed, so
2209 * root->reloc_root may not be set, return ENOENT in this case.
2210 */
2211 if (!root)
2212 return ERR_PTR(-ENOENT);
2213
2214 if (next->new_bytenr != root->node->start) {
2215 /*
2216 * We just created the reloc root, so we shouldn't have
2217 * ->new_bytenr set and this shouldn't be in the changed
2218 * list. If it is then we have multiple roots pointing
2219 * at the same bytenr which indicates corruption, or
2220 * we've made a mistake in the backref walking code.
2221 */
2222 ASSERT(next->new_bytenr == 0);
2223 ASSERT(list_empty(&next->list));
2224 if (next->new_bytenr || !list_empty(&next->list)) {
2225 btrfs_err(trans->fs_info,
2226 "bytenr %llu possibly has multiple roots pointing at the same bytenr %llu",
2227 node->bytenr, next->bytenr);
2228 return ERR_PTR(-EUCLEAN);
2229 }
2230
2231 next->new_bytenr = root->node->start;
2232 btrfs_put_root(next->root);
2233 next->root = btrfs_grab_root(root);
2234 ASSERT(next->root);
2235 list_add_tail(&next->list,
2236 &rc->backref_cache.changed);
2237 mark_block_processed(rc, next);
2238 break;
2239 }
2240
2241 WARN_ON(1);
2242 root = NULL;
2243 next = walk_down_backref(edges, &index);
2244 if (!next || next->level <= node->level)
2245 break;
2246 }
2247 if (!root) {
2248 /*
2249 * This can happen if there's fs corruption or if there's a bug
2250 * in the backref lookup code.
2251 */
2252 ASSERT(0);
2253 return ERR_PTR(-ENOENT);
2254 }
2255
2256 next = node;
2257 /* setup backref node path for btrfs_reloc_cow_block */
2258 while (1) {
2259 rc->backref_cache.path[next->level] = next;
2260 if (--index < 0)
2261 break;
2262 next = edges[index]->node[UPPER];
2263 }
2264 return root;
2265}
2266
2267/*
2268 * Select a tree root for relocation.
2269 *
2270 * Return NULL if the block is not shareable. We should use do_relocation() in
2271 * this case.
2272 *
2273 * Return a tree root pointer if the block is shareable.
2274 * Return -ENOENT if the block is root of reloc tree.
2275 */
2276static noinline_for_stack
2277struct btrfs_root *select_one_root(struct btrfs_backref_node *node)
2278{
2279 struct btrfs_backref_node *next;
2280 struct btrfs_root *root;
2281 struct btrfs_root *fs_root = NULL;
2282 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2283 int index = 0;
2284
2285 next = node;
2286 while (1) {
2287 cond_resched();
2288 next = walk_up_backref(next, edges, &index);
2289 root = next->root;
2290
2291 /*
2292 * This can occur if we have incomplete extent refs leading all
2293 * the way up a particular path, in this case return -EUCLEAN.
2294 */
2295 if (!root)
2296 return ERR_PTR(-EUCLEAN);
2297
2298 /* No other choice for non-shareable tree */
2299 if (!test_bit(BTRFS_ROOT_SHAREABLE, &root->state))
2300 return root;
2301
2302 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2303 fs_root = root;
2304
2305 if (next != node)
2306 return NULL;
2307
2308 next = walk_down_backref(edges, &index);
2309 if (!next || next->level <= node->level)
2310 break;
2311 }
2312
2313 if (!fs_root)
2314 return ERR_PTR(-ENOENT);
2315 return fs_root;
2316}
2317
2318static noinline_for_stack
2319u64 calcu_metadata_size(struct reloc_control *rc,
2320 struct btrfs_backref_node *node, int reserve)
2321{
2322 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2323 struct btrfs_backref_node *next = node;
2324 struct btrfs_backref_edge *edge;
2325 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2326 u64 num_bytes = 0;
2327 int index = 0;
2328
2329 BUG_ON(reserve && node->processed);
2330
2331 while (next) {
2332 cond_resched();
2333 while (1) {
2334 if (next->processed && (reserve || next != node))
2335 break;
2336
2337 num_bytes += fs_info->nodesize;
2338
2339 if (list_empty(&next->upper))
2340 break;
2341
2342 edge = list_entry(next->upper.next,
2343 struct btrfs_backref_edge, list[LOWER]);
2344 edges[index++] = edge;
2345 next = edge->node[UPPER];
2346 }
2347 next = walk_down_backref(edges, &index);
2348 }
2349 return num_bytes;
2350}
2351
2352static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2353 struct reloc_control *rc,
2354 struct btrfs_backref_node *node)
2355{
2356 struct btrfs_root *root = rc->extent_root;
2357 struct btrfs_fs_info *fs_info = root->fs_info;
2358 u64 num_bytes;
2359 int ret;
2360 u64 tmp;
2361
2362 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2363
2364 trans->block_rsv = rc->block_rsv;
2365 rc->reserved_bytes += num_bytes;
2366
2367 /*
2368 * We are under a transaction here so we can only do limited flushing.
2369 * If we get an enospc just kick back -EAGAIN so we know to drop the
2370 * transaction and try to refill when we can flush all the things.
2371 */
2372 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv, num_bytes,
2373 BTRFS_RESERVE_FLUSH_LIMIT);
2374 if (ret) {
2375 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2376 while (tmp <= rc->reserved_bytes)
2377 tmp <<= 1;
2378 /*
2379 * only one thread can access block_rsv at this point,
2380 * so we don't need hold lock to protect block_rsv.
2381 * we expand more reservation size here to allow enough
2382 * space for relocation and we will return earlier in
2383 * enospc case.
2384 */
2385 rc->block_rsv->size = tmp + fs_info->nodesize *
2386 RELOCATION_RESERVED_NODES;
2387 return -EAGAIN;
2388 }
2389
2390 return 0;
2391}
2392
2393/*
2394 * relocate a block tree, and then update pointers in upper level
2395 * blocks that reference the block to point to the new location.
2396 *
2397 * if called by link_to_upper, the block has already been relocated.
2398 * in that case this function just updates pointers.
2399 */
2400static int do_relocation(struct btrfs_trans_handle *trans,
2401 struct reloc_control *rc,
2402 struct btrfs_backref_node *node,
2403 struct btrfs_key *key,
2404 struct btrfs_path *path, int lowest)
2405{
2406 struct btrfs_backref_node *upper;
2407 struct btrfs_backref_edge *edge;
2408 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2409 struct btrfs_root *root;
2410 struct extent_buffer *eb;
2411 u32 blocksize;
2412 u64 bytenr;
2413 int slot;
2414 int ret = 0;
2415
2416 /*
2417 * If we are lowest then this is the first time we're processing this
2418 * block, and thus shouldn't have an eb associated with it yet.
2419 */
2420 ASSERT(!lowest || !node->eb);
2421
2422 path->lowest_level = node->level + 1;
2423 rc->backref_cache.path[node->level] = node;
2424 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2425 struct btrfs_ref ref = { 0 };
2426
2427 cond_resched();
2428
2429 upper = edge->node[UPPER];
2430 root = select_reloc_root(trans, rc, upper, edges);
2431 if (IS_ERR(root)) {
2432 ret = PTR_ERR(root);
2433 goto next;
2434 }
2435
2436 if (upper->eb && !upper->locked) {
2437 if (!lowest) {
2438 ret = btrfs_bin_search(upper->eb, 0, key, &slot);
2439 if (ret < 0)
2440 goto next;
2441 BUG_ON(ret);
2442 bytenr = btrfs_node_blockptr(upper->eb, slot);
2443 if (node->eb->start == bytenr)
2444 goto next;
2445 }
2446 btrfs_backref_drop_node_buffer(upper);
2447 }
2448
2449 if (!upper->eb) {
2450 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2451 if (ret) {
2452 if (ret > 0)
2453 ret = -ENOENT;
2454
2455 btrfs_release_path(path);
2456 break;
2457 }
2458
2459 if (!upper->eb) {
2460 upper->eb = path->nodes[upper->level];
2461 path->nodes[upper->level] = NULL;
2462 } else {
2463 BUG_ON(upper->eb != path->nodes[upper->level]);
2464 }
2465
2466 upper->locked = 1;
2467 path->locks[upper->level] = 0;
2468
2469 slot = path->slots[upper->level];
2470 btrfs_release_path(path);
2471 } else {
2472 ret = btrfs_bin_search(upper->eb, 0, key, &slot);
2473 if (ret < 0)
2474 goto next;
2475 BUG_ON(ret);
2476 }
2477
2478 bytenr = btrfs_node_blockptr(upper->eb, slot);
2479 if (lowest) {
2480 if (bytenr != node->bytenr) {
2481 btrfs_err(root->fs_info,
2482 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2483 bytenr, node->bytenr, slot,
2484 upper->eb->start);
2485 ret = -EIO;
2486 goto next;
2487 }
2488 } else {
2489 if (node->eb->start == bytenr)
2490 goto next;
2491 }
2492
2493 blocksize = root->fs_info->nodesize;
2494 eb = btrfs_read_node_slot(upper->eb, slot);
2495 if (IS_ERR(eb)) {
2496 ret = PTR_ERR(eb);
2497 goto next;
2498 }
2499 btrfs_tree_lock(eb);
2500
2501 if (!node->eb) {
2502 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2503 slot, &eb, BTRFS_NESTING_COW);
2504 btrfs_tree_unlock(eb);
2505 free_extent_buffer(eb);
2506 if (ret < 0)
2507 goto next;
2508 /*
2509 * We've just COWed this block, it should have updated
2510 * the correct backref node entry.
2511 */
2512 ASSERT(node->eb == eb);
2513 } else {
2514 btrfs_set_node_blockptr(upper->eb, slot,
2515 node->eb->start);
2516 btrfs_set_node_ptr_generation(upper->eb, slot,
2517 trans->transid);
2518 btrfs_mark_buffer_dirty(trans, upper->eb);
2519
2520 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2521 node->eb->start, blocksize,
2522 upper->eb->start,
2523 btrfs_header_owner(upper->eb));
2524 btrfs_init_tree_ref(&ref, node->level,
2525 btrfs_header_owner(upper->eb),
2526 root->root_key.objectid, false);
2527 ret = btrfs_inc_extent_ref(trans, &ref);
2528 if (!ret)
2529 ret = btrfs_drop_subtree(trans, root, eb,
2530 upper->eb);
2531 if (ret)
2532 btrfs_abort_transaction(trans, ret);
2533 }
2534next:
2535 if (!upper->pending)
2536 btrfs_backref_drop_node_buffer(upper);
2537 else
2538 btrfs_backref_unlock_node_buffer(upper);
2539 if (ret)
2540 break;
2541 }
2542
2543 if (!ret && node->pending) {
2544 btrfs_backref_drop_node_buffer(node);
2545 list_move_tail(&node->list, &rc->backref_cache.changed);
2546 node->pending = 0;
2547 }
2548
2549 path->lowest_level = 0;
2550
2551 /*
2552 * We should have allocated all of our space in the block rsv and thus
2553 * shouldn't ENOSPC.
2554 */
2555 ASSERT(ret != -ENOSPC);
2556 return ret;
2557}
2558
2559static int link_to_upper(struct btrfs_trans_handle *trans,
2560 struct reloc_control *rc,
2561 struct btrfs_backref_node *node,
2562 struct btrfs_path *path)
2563{
2564 struct btrfs_key key;
2565
2566 btrfs_node_key_to_cpu(node->eb, &key, 0);
2567 return do_relocation(trans, rc, node, &key, path, 0);
2568}
2569
2570static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2571 struct reloc_control *rc,
2572 struct btrfs_path *path, int err)
2573{
2574 LIST_HEAD(list);
2575 struct btrfs_backref_cache *cache = &rc->backref_cache;
2576 struct btrfs_backref_node *node;
2577 int level;
2578 int ret;
2579
2580 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2581 while (!list_empty(&cache->pending[level])) {
2582 node = list_entry(cache->pending[level].next,
2583 struct btrfs_backref_node, list);
2584 list_move_tail(&node->list, &list);
2585 BUG_ON(!node->pending);
2586
2587 if (!err) {
2588 ret = link_to_upper(trans, rc, node, path);
2589 if (ret < 0)
2590 err = ret;
2591 }
2592 }
2593 list_splice_init(&list, &cache->pending[level]);
2594 }
2595 return err;
2596}
2597
2598/*
2599 * mark a block and all blocks directly/indirectly reference the block
2600 * as processed.
2601 */
2602static void update_processed_blocks(struct reloc_control *rc,
2603 struct btrfs_backref_node *node)
2604{
2605 struct btrfs_backref_node *next = node;
2606 struct btrfs_backref_edge *edge;
2607 struct btrfs_backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2608 int index = 0;
2609
2610 while (next) {
2611 cond_resched();
2612 while (1) {
2613 if (next->processed)
2614 break;
2615
2616 mark_block_processed(rc, next);
2617
2618 if (list_empty(&next->upper))
2619 break;
2620
2621 edge = list_entry(next->upper.next,
2622 struct btrfs_backref_edge, list[LOWER]);
2623 edges[index++] = edge;
2624 next = edge->node[UPPER];
2625 }
2626 next = walk_down_backref(edges, &index);
2627 }
2628}
2629
2630static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2631{
2632 u32 blocksize = rc->extent_root->fs_info->nodesize;
2633
2634 if (test_range_bit(&rc->processed_blocks, bytenr,
2635 bytenr + blocksize - 1, EXTENT_DIRTY, NULL))
2636 return 1;
2637 return 0;
2638}
2639
2640static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2641 struct tree_block *block)
2642{
2643 struct btrfs_tree_parent_check check = {
2644 .level = block->level,
2645 .owner_root = block->owner,
2646 .transid = block->key.offset
2647 };
2648 struct extent_buffer *eb;
2649
2650 eb = read_tree_block(fs_info, block->bytenr, &check);
2651 if (IS_ERR(eb))
2652 return PTR_ERR(eb);
2653 if (!extent_buffer_uptodate(eb)) {
2654 free_extent_buffer(eb);
2655 return -EIO;
2656 }
2657 if (block->level == 0)
2658 btrfs_item_key_to_cpu(eb, &block->key, 0);
2659 else
2660 btrfs_node_key_to_cpu(eb, &block->key, 0);
2661 free_extent_buffer(eb);
2662 block->key_ready = true;
2663 return 0;
2664}
2665
2666/*
2667 * helper function to relocate a tree block
2668 */
2669static int relocate_tree_block(struct btrfs_trans_handle *trans,
2670 struct reloc_control *rc,
2671 struct btrfs_backref_node *node,
2672 struct btrfs_key *key,
2673 struct btrfs_path *path)
2674{
2675 struct btrfs_root *root;
2676 int ret = 0;
2677
2678 if (!node)
2679 return 0;
2680
2681 /*
2682 * If we fail here we want to drop our backref_node because we are going
2683 * to start over and regenerate the tree for it.
2684 */
2685 ret = reserve_metadata_space(trans, rc, node);
2686 if (ret)
2687 goto out;
2688
2689 BUG_ON(node->processed);
2690 root = select_one_root(node);
2691 if (IS_ERR(root)) {
2692 ret = PTR_ERR(root);
2693
2694 /* See explanation in select_one_root for the -EUCLEAN case. */
2695 ASSERT(ret == -ENOENT);
2696 if (ret == -ENOENT) {
2697 ret = 0;
2698 update_processed_blocks(rc, node);
2699 }
2700 goto out;
2701 }
2702
2703 if (root) {
2704 if (test_bit(BTRFS_ROOT_SHAREABLE, &root->state)) {
2705 /*
2706 * This block was the root block of a root, and this is
2707 * the first time we're processing the block and thus it
2708 * should not have had the ->new_bytenr modified and
2709 * should have not been included on the changed list.
2710 *
2711 * However in the case of corruption we could have
2712 * multiple refs pointing to the same block improperly,
2713 * and thus we would trip over these checks. ASSERT()
2714 * for the developer case, because it could indicate a
2715 * bug in the backref code, however error out for a
2716 * normal user in the case of corruption.
2717 */
2718 ASSERT(node->new_bytenr == 0);
2719 ASSERT(list_empty(&node->list));
2720 if (node->new_bytenr || !list_empty(&node->list)) {
2721 btrfs_err(root->fs_info,
2722 "bytenr %llu has improper references to it",
2723 node->bytenr);
2724 ret = -EUCLEAN;
2725 goto out;
2726 }
2727 ret = btrfs_record_root_in_trans(trans, root);
2728 if (ret)
2729 goto out;
2730 /*
2731 * Another thread could have failed, need to check if we
2732 * have reloc_root actually set.
2733 */
2734 if (!root->reloc_root) {
2735 ret = -ENOENT;
2736 goto out;
2737 }
2738 root = root->reloc_root;
2739 node->new_bytenr = root->node->start;
2740 btrfs_put_root(node->root);
2741 node->root = btrfs_grab_root(root);
2742 ASSERT(node->root);
2743 list_add_tail(&node->list, &rc->backref_cache.changed);
2744 } else {
2745 path->lowest_level = node->level;
2746 if (root == root->fs_info->chunk_root)
2747 btrfs_reserve_chunk_metadata(trans, false);
2748 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2749 btrfs_release_path(path);
2750 if (root == root->fs_info->chunk_root)
2751 btrfs_trans_release_chunk_metadata(trans);
2752 if (ret > 0)
2753 ret = 0;
2754 }
2755 if (!ret)
2756 update_processed_blocks(rc, node);
2757 } else {
2758 ret = do_relocation(trans, rc, node, key, path, 1);
2759 }
2760out:
2761 if (ret || node->level == 0 || node->cowonly)
2762 btrfs_backref_cleanup_node(&rc->backref_cache, node);
2763 return ret;
2764}
2765
2766/*
2767 * relocate a list of blocks
2768 */
2769static noinline_for_stack
2770int relocate_tree_blocks(struct btrfs_trans_handle *trans,
2771 struct reloc_control *rc, struct rb_root *blocks)
2772{
2773 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2774 struct btrfs_backref_node *node;
2775 struct btrfs_path *path;
2776 struct tree_block *block;
2777 struct tree_block *next;
2778 int ret;
2779 int err = 0;
2780
2781 path = btrfs_alloc_path();
2782 if (!path) {
2783 err = -ENOMEM;
2784 goto out_free_blocks;
2785 }
2786
2787 /* Kick in readahead for tree blocks with missing keys */
2788 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2789 if (!block->key_ready)
2790 btrfs_readahead_tree_block(fs_info, block->bytenr,
2791 block->owner, 0,
2792 block->level);
2793 }
2794
2795 /* Get first keys */
2796 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2797 if (!block->key_ready) {
2798 err = get_tree_block_key(fs_info, block);
2799 if (err)
2800 goto out_free_path;
2801 }
2802 }
2803
2804 /* Do tree relocation */
2805 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
2806 node = build_backref_tree(trans, rc, &block->key,
2807 block->level, block->bytenr);
2808 if (IS_ERR(node)) {
2809 err = PTR_ERR(node);
2810 goto out;
2811 }
2812
2813 ret = relocate_tree_block(trans, rc, node, &block->key,
2814 path);
2815 if (ret < 0) {
2816 err = ret;
2817 break;
2818 }
2819 }
2820out:
2821 err = finish_pending_nodes(trans, rc, path, err);
2822
2823out_free_path:
2824 btrfs_free_path(path);
2825out_free_blocks:
2826 free_block_list(blocks);
2827 return err;
2828}
2829
2830static noinline_for_stack int prealloc_file_extent_cluster(
2831 struct btrfs_inode *inode,
2832 const struct file_extent_cluster *cluster)
2833{
2834 u64 alloc_hint = 0;
2835 u64 start;
2836 u64 end;
2837 u64 offset = inode->index_cnt;
2838 u64 num_bytes;
2839 int nr;
2840 int ret = 0;
2841 u64 i_size = i_size_read(&inode->vfs_inode);
2842 u64 prealloc_start = cluster->start - offset;
2843 u64 prealloc_end = cluster->end - offset;
2844 u64 cur_offset = prealloc_start;
2845
2846 /*
2847 * For subpage case, previous i_size may not be aligned to PAGE_SIZE.
2848 * This means the range [i_size, PAGE_END + 1) is filled with zeros by
2849 * btrfs_do_readpage() call of previously relocated file cluster.
2850 *
2851 * If the current cluster starts in the above range, btrfs_do_readpage()
2852 * will skip the read, and relocate_one_page() will later writeback
2853 * the padding zeros as new data, causing data corruption.
2854 *
2855 * Here we have to manually invalidate the range (i_size, PAGE_END + 1).
2856 */
2857 if (!PAGE_ALIGNED(i_size)) {
2858 struct address_space *mapping = inode->vfs_inode.i_mapping;
2859 struct btrfs_fs_info *fs_info = inode->root->fs_info;
2860 const u32 sectorsize = fs_info->sectorsize;
2861 struct page *page;
2862
2863 ASSERT(sectorsize < PAGE_SIZE);
2864 ASSERT(IS_ALIGNED(i_size, sectorsize));
2865
2866 /*
2867 * Subpage can't handle page with DIRTY but without UPTODATE
2868 * bit as it can lead to the following deadlock:
2869 *
2870 * btrfs_read_folio()
2871 * | Page already *locked*
2872 * |- btrfs_lock_and_flush_ordered_range()
2873 * |- btrfs_start_ordered_extent()
2874 * |- extent_write_cache_pages()
2875 * |- lock_page()
2876 * We try to lock the page we already hold.
2877 *
2878 * Here we just writeback the whole data reloc inode, so that
2879 * we will be ensured to have no dirty range in the page, and
2880 * are safe to clear the uptodate bits.
2881 *
2882 * This shouldn't cause too much overhead, as we need to write
2883 * the data back anyway.
2884 */
2885 ret = filemap_write_and_wait(mapping);
2886 if (ret < 0)
2887 return ret;
2888
2889 clear_extent_bits(&inode->io_tree, i_size,
2890 round_up(i_size, PAGE_SIZE) - 1,
2891 EXTENT_UPTODATE);
2892 page = find_lock_page(mapping, i_size >> PAGE_SHIFT);
2893 /*
2894 * If page is freed we don't need to do anything then, as we
2895 * will re-read the whole page anyway.
2896 */
2897 if (page) {
2898 btrfs_subpage_clear_uptodate(fs_info, page_folio(page), i_size,
2899 round_up(i_size, PAGE_SIZE) - i_size);
2900 unlock_page(page);
2901 put_page(page);
2902 }
2903 }
2904
2905 BUG_ON(cluster->start != cluster->boundary[0]);
2906 ret = btrfs_alloc_data_chunk_ondemand(inode,
2907 prealloc_end + 1 - prealloc_start);
2908 if (ret)
2909 return ret;
2910
2911 btrfs_inode_lock(inode, 0);
2912 for (nr = 0; nr < cluster->nr; nr++) {
2913 struct extent_state *cached_state = NULL;
2914
2915 start = cluster->boundary[nr] - offset;
2916 if (nr + 1 < cluster->nr)
2917 end = cluster->boundary[nr + 1] - 1 - offset;
2918 else
2919 end = cluster->end - offset;
2920
2921 lock_extent(&inode->io_tree, start, end, &cached_state);
2922 num_bytes = end + 1 - start;
2923 ret = btrfs_prealloc_file_range(&inode->vfs_inode, 0, start,
2924 num_bytes, num_bytes,
2925 end + 1, &alloc_hint);
2926 cur_offset = end + 1;
2927 unlock_extent(&inode->io_tree, start, end, &cached_state);
2928 if (ret)
2929 break;
2930 }
2931 btrfs_inode_unlock(inode, 0);
2932
2933 if (cur_offset < prealloc_end)
2934 btrfs_free_reserved_data_space_noquota(inode->root->fs_info,
2935 prealloc_end + 1 - cur_offset);
2936 return ret;
2937}
2938
2939static noinline_for_stack int setup_relocation_extent_mapping(struct inode *inode,
2940 u64 start, u64 end, u64 block_start)
2941{
2942 struct extent_map *em;
2943 struct extent_state *cached_state = NULL;
2944 int ret = 0;
2945
2946 em = alloc_extent_map();
2947 if (!em)
2948 return -ENOMEM;
2949
2950 em->start = start;
2951 em->len = end + 1 - start;
2952 em->block_len = em->len;
2953 em->block_start = block_start;
2954 em->flags |= EXTENT_FLAG_PINNED;
2955
2956 lock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2957 ret = btrfs_replace_extent_map_range(BTRFS_I(inode), em, false);
2958 unlock_extent(&BTRFS_I(inode)->io_tree, start, end, &cached_state);
2959 free_extent_map(em);
2960
2961 return ret;
2962}
2963
2964/*
2965 * Allow error injection to test balance/relocation cancellation
2966 */
2967noinline int btrfs_should_cancel_balance(const struct btrfs_fs_info *fs_info)
2968{
2969 return atomic_read(&fs_info->balance_cancel_req) ||
2970 atomic_read(&fs_info->reloc_cancel_req) ||
2971 fatal_signal_pending(current);
2972}
2973ALLOW_ERROR_INJECTION(btrfs_should_cancel_balance, TRUE);
2974
2975static u64 get_cluster_boundary_end(const struct file_extent_cluster *cluster,
2976 int cluster_nr)
2977{
2978 /* Last extent, use cluster end directly */
2979 if (cluster_nr >= cluster->nr - 1)
2980 return cluster->end;
2981
2982 /* Use next boundary start*/
2983 return cluster->boundary[cluster_nr + 1] - 1;
2984}
2985
2986static int relocate_one_page(struct inode *inode, struct file_ra_state *ra,
2987 const struct file_extent_cluster *cluster,
2988 int *cluster_nr, unsigned long page_index)
2989{
2990 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
2991 u64 offset = BTRFS_I(inode)->index_cnt;
2992 const unsigned long last_index = (cluster->end - offset) >> PAGE_SHIFT;
2993 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
2994 struct page *page;
2995 u64 page_start;
2996 u64 page_end;
2997 u64 cur;
2998 int ret;
2999
3000 ASSERT(page_index <= last_index);
3001 page = find_lock_page(inode->i_mapping, page_index);
3002 if (!page) {
3003 page_cache_sync_readahead(inode->i_mapping, ra, NULL,
3004 page_index, last_index + 1 - page_index);
3005 page = find_or_create_page(inode->i_mapping, page_index, mask);
3006 if (!page)
3007 return -ENOMEM;
3008 }
3009
3010 if (PageReadahead(page))
3011 page_cache_async_readahead(inode->i_mapping, ra, NULL,
3012 page_folio(page), page_index,
3013 last_index + 1 - page_index);
3014
3015 if (!PageUptodate(page)) {
3016 btrfs_read_folio(NULL, page_folio(page));
3017 lock_page(page);
3018 if (!PageUptodate(page)) {
3019 ret = -EIO;
3020 goto release_page;
3021 }
3022 }
3023
3024 /*
3025 * We could have lost page private when we dropped the lock to read the
3026 * page above, make sure we set_page_extent_mapped here so we have any
3027 * of the subpage blocksize stuff we need in place.
3028 */
3029 ret = set_page_extent_mapped(page);
3030 if (ret < 0)
3031 goto release_page;
3032
3033 page_start = page_offset(page);
3034 page_end = page_start + PAGE_SIZE - 1;
3035
3036 /*
3037 * Start from the cluster, as for subpage case, the cluster can start
3038 * inside the page.
3039 */
3040 cur = max(page_start, cluster->boundary[*cluster_nr] - offset);
3041 while (cur <= page_end) {
3042 struct extent_state *cached_state = NULL;
3043 u64 extent_start = cluster->boundary[*cluster_nr] - offset;
3044 u64 extent_end = get_cluster_boundary_end(cluster,
3045 *cluster_nr) - offset;
3046 u64 clamped_start = max(page_start, extent_start);
3047 u64 clamped_end = min(page_end, extent_end);
3048 u32 clamped_len = clamped_end + 1 - clamped_start;
3049
3050 /* Reserve metadata for this range */
3051 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3052 clamped_len, clamped_len,
3053 false);
3054 if (ret)
3055 goto release_page;
3056
3057 /* Mark the range delalloc and dirty for later writeback */
3058 lock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3059 &cached_state);
3060 ret = btrfs_set_extent_delalloc(BTRFS_I(inode), clamped_start,
3061 clamped_end, 0, &cached_state);
3062 if (ret) {
3063 clear_extent_bit(&BTRFS_I(inode)->io_tree,
3064 clamped_start, clamped_end,
3065 EXTENT_LOCKED | EXTENT_BOUNDARY,
3066 &cached_state);
3067 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3068 clamped_len, true);
3069 btrfs_delalloc_release_extents(BTRFS_I(inode),
3070 clamped_len);
3071 goto release_page;
3072 }
3073 btrfs_folio_set_dirty(fs_info, page_folio(page),
3074 clamped_start, clamped_len);
3075
3076 /*
3077 * Set the boundary if it's inside the page.
3078 * Data relocation requires the destination extents to have the
3079 * same size as the source.
3080 * EXTENT_BOUNDARY bit prevents current extent from being merged
3081 * with previous extent.
3082 */
3083 if (in_range(cluster->boundary[*cluster_nr] - offset,
3084 page_start, PAGE_SIZE)) {
3085 u64 boundary_start = cluster->boundary[*cluster_nr] -
3086 offset;
3087 u64 boundary_end = boundary_start +
3088 fs_info->sectorsize - 1;
3089
3090 set_extent_bit(&BTRFS_I(inode)->io_tree,
3091 boundary_start, boundary_end,
3092 EXTENT_BOUNDARY, NULL);
3093 }
3094 unlock_extent(&BTRFS_I(inode)->io_tree, clamped_start, clamped_end,
3095 &cached_state);
3096 btrfs_delalloc_release_extents(BTRFS_I(inode), clamped_len);
3097 cur += clamped_len;
3098
3099 /* Crossed extent end, go to next extent */
3100 if (cur >= extent_end) {
3101 (*cluster_nr)++;
3102 /* Just finished the last extent of the cluster, exit. */
3103 if (*cluster_nr >= cluster->nr)
3104 break;
3105 }
3106 }
3107 unlock_page(page);
3108 put_page(page);
3109
3110 balance_dirty_pages_ratelimited(inode->i_mapping);
3111 btrfs_throttle(fs_info);
3112 if (btrfs_should_cancel_balance(fs_info))
3113 ret = -ECANCELED;
3114 return ret;
3115
3116release_page:
3117 unlock_page(page);
3118 put_page(page);
3119 return ret;
3120}
3121
3122static int relocate_file_extent_cluster(struct inode *inode,
3123 const struct file_extent_cluster *cluster)
3124{
3125 u64 offset = BTRFS_I(inode)->index_cnt;
3126 unsigned long index;
3127 unsigned long last_index;
3128 struct file_ra_state *ra;
3129 int cluster_nr = 0;
3130 int ret = 0;
3131
3132 if (!cluster->nr)
3133 return 0;
3134
3135 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3136 if (!ra)
3137 return -ENOMEM;
3138
3139 ret = prealloc_file_extent_cluster(BTRFS_I(inode), cluster);
3140 if (ret)
3141 goto out;
3142
3143 file_ra_state_init(ra, inode->i_mapping);
3144
3145 ret = setup_relocation_extent_mapping(inode, cluster->start - offset,
3146 cluster->end - offset, cluster->start);
3147 if (ret)
3148 goto out;
3149
3150 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3151 for (index = (cluster->start - offset) >> PAGE_SHIFT;
3152 index <= last_index && !ret; index++)
3153 ret = relocate_one_page(inode, ra, cluster, &cluster_nr, index);
3154 if (ret == 0)
3155 WARN_ON(cluster_nr != cluster->nr);
3156out:
3157 kfree(ra);
3158 return ret;
3159}
3160
3161static noinline_for_stack int relocate_data_extent(struct inode *inode,
3162 const struct btrfs_key *extent_key,
3163 struct file_extent_cluster *cluster)
3164{
3165 int ret;
3166 struct btrfs_root *root = BTRFS_I(inode)->root;
3167
3168 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3169 ret = relocate_file_extent_cluster(inode, cluster);
3170 if (ret)
3171 return ret;
3172 cluster->nr = 0;
3173 }
3174
3175 /*
3176 * Under simple quotas, we set root->relocation_src_root when we find
3177 * the extent. If adjacent extents have different owners, we can't merge
3178 * them while relocating. Handle this by storing the owning root that
3179 * started a cluster and if we see an extent from a different root break
3180 * cluster formation (just like the above case of non-adjacent extents).
3181 *
3182 * Without simple quotas, relocation_src_root is always 0, so we should
3183 * never see a mismatch, and it should have no effect on relocation
3184 * clusters.
3185 */
3186 if (cluster->nr > 0 && cluster->owning_root != root->relocation_src_root) {
3187 u64 tmp = root->relocation_src_root;
3188
3189 /*
3190 * root->relocation_src_root is the state that actually affects
3191 * the preallocation we do here, so set it to the root owning
3192 * the cluster we need to relocate.
3193 */
3194 root->relocation_src_root = cluster->owning_root;
3195 ret = relocate_file_extent_cluster(inode, cluster);
3196 if (ret)
3197 return ret;
3198 cluster->nr = 0;
3199 /* And reset it back for the current extent's owning root. */
3200 root->relocation_src_root = tmp;
3201 }
3202
3203 if (!cluster->nr) {
3204 cluster->start = extent_key->objectid;
3205 cluster->owning_root = root->relocation_src_root;
3206 }
3207 else
3208 BUG_ON(cluster->nr >= MAX_EXTENTS);
3209 cluster->end = extent_key->objectid + extent_key->offset - 1;
3210 cluster->boundary[cluster->nr] = extent_key->objectid;
3211 cluster->nr++;
3212
3213 if (cluster->nr >= MAX_EXTENTS) {
3214 ret = relocate_file_extent_cluster(inode, cluster);
3215 if (ret)
3216 return ret;
3217 cluster->nr = 0;
3218 }
3219 return 0;
3220}
3221
3222/*
3223 * helper to add a tree block to the list.
3224 * the major work is getting the generation and level of the block
3225 */
3226static int add_tree_block(struct reloc_control *rc,
3227 const struct btrfs_key *extent_key,
3228 struct btrfs_path *path,
3229 struct rb_root *blocks)
3230{
3231 struct extent_buffer *eb;
3232 struct btrfs_extent_item *ei;
3233 struct btrfs_tree_block_info *bi;
3234 struct tree_block *block;
3235 struct rb_node *rb_node;
3236 u32 item_size;
3237 int level = -1;
3238 u64 generation;
3239 u64 owner = 0;
3240
3241 eb = path->nodes[0];
3242 item_size = btrfs_item_size(eb, path->slots[0]);
3243
3244 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3245 item_size >= sizeof(*ei) + sizeof(*bi)) {
3246 unsigned long ptr = 0, end;
3247
3248 ei = btrfs_item_ptr(eb, path->slots[0],
3249 struct btrfs_extent_item);
3250 end = (unsigned long)ei + item_size;
3251 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3252 bi = (struct btrfs_tree_block_info *)(ei + 1);
3253 level = btrfs_tree_block_level(eb, bi);
3254 ptr = (unsigned long)(bi + 1);
3255 } else {
3256 level = (int)extent_key->offset;
3257 ptr = (unsigned long)(ei + 1);
3258 }
3259 generation = btrfs_extent_generation(eb, ei);
3260
3261 /*
3262 * We're reading random blocks without knowing their owner ahead
3263 * of time. This is ok most of the time, as all reloc roots and
3264 * fs roots have the same lock type. However normal trees do
3265 * not, and the only way to know ahead of time is to read the
3266 * inline ref offset. We know it's an fs root if
3267 *
3268 * 1. There's more than one ref.
3269 * 2. There's a SHARED_DATA_REF_KEY set.
3270 * 3. FULL_BACKREF is set on the flags.
3271 *
3272 * Otherwise it's safe to assume that the ref offset == the
3273 * owner of this block, so we can use that when calling
3274 * read_tree_block.
3275 */
3276 if (btrfs_extent_refs(eb, ei) == 1 &&
3277 !(btrfs_extent_flags(eb, ei) &
3278 BTRFS_BLOCK_FLAG_FULL_BACKREF) &&
3279 ptr < end) {
3280 struct btrfs_extent_inline_ref *iref;
3281 int type;
3282
3283 iref = (struct btrfs_extent_inline_ref *)ptr;
3284 type = btrfs_get_extent_inline_ref_type(eb, iref,
3285 BTRFS_REF_TYPE_BLOCK);
3286 if (type == BTRFS_REF_TYPE_INVALID)
3287 return -EINVAL;
3288 if (type == BTRFS_TREE_BLOCK_REF_KEY)
3289 owner = btrfs_extent_inline_ref_offset(eb, iref);
3290 }
3291 } else {
3292 btrfs_print_leaf(eb);
3293 btrfs_err(rc->block_group->fs_info,
3294 "unrecognized tree backref at tree block %llu slot %u",
3295 eb->start, path->slots[0]);
3296 btrfs_release_path(path);
3297 return -EUCLEAN;
3298 }
3299
3300 btrfs_release_path(path);
3301
3302 BUG_ON(level == -1);
3303
3304 block = kmalloc(sizeof(*block), GFP_NOFS);
3305 if (!block)
3306 return -ENOMEM;
3307
3308 block->bytenr = extent_key->objectid;
3309 block->key.objectid = rc->extent_root->fs_info->nodesize;
3310 block->key.offset = generation;
3311 block->level = level;
3312 block->key_ready = false;
3313 block->owner = owner;
3314
3315 rb_node = rb_simple_insert(blocks, block->bytenr, &block->rb_node);
3316 if (rb_node)
3317 btrfs_backref_panic(rc->extent_root->fs_info, block->bytenr,
3318 -EEXIST);
3319
3320 return 0;
3321}
3322
3323/*
3324 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3325 */
3326static int __add_tree_block(struct reloc_control *rc,
3327 u64 bytenr, u32 blocksize,
3328 struct rb_root *blocks)
3329{
3330 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3331 struct btrfs_path *path;
3332 struct btrfs_key key;
3333 int ret;
3334 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3335
3336 if (tree_block_processed(bytenr, rc))
3337 return 0;
3338
3339 if (rb_simple_search(blocks, bytenr))
3340 return 0;
3341
3342 path = btrfs_alloc_path();
3343 if (!path)
3344 return -ENOMEM;
3345again:
3346 key.objectid = bytenr;
3347 if (skinny) {
3348 key.type = BTRFS_METADATA_ITEM_KEY;
3349 key.offset = (u64)-1;
3350 } else {
3351 key.type = BTRFS_EXTENT_ITEM_KEY;
3352 key.offset = blocksize;
3353 }
3354
3355 path->search_commit_root = 1;
3356 path->skip_locking = 1;
3357 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3358 if (ret < 0)
3359 goto out;
3360
3361 if (ret > 0 && skinny) {
3362 if (path->slots[0]) {
3363 path->slots[0]--;
3364 btrfs_item_key_to_cpu(path->nodes[0], &key,
3365 path->slots[0]);
3366 if (key.objectid == bytenr &&
3367 (key.type == BTRFS_METADATA_ITEM_KEY ||
3368 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3369 key.offset == blocksize)))
3370 ret = 0;
3371 }
3372
3373 if (ret) {
3374 skinny = false;
3375 btrfs_release_path(path);
3376 goto again;
3377 }
3378 }
3379 if (ret) {
3380 ASSERT(ret == 1);
3381 btrfs_print_leaf(path->nodes[0]);
3382 btrfs_err(fs_info,
3383 "tree block extent item (%llu) is not found in extent tree",
3384 bytenr);
3385 WARN_ON(1);
3386 ret = -EINVAL;
3387 goto out;
3388 }
3389
3390 ret = add_tree_block(rc, &key, path, blocks);
3391out:
3392 btrfs_free_path(path);
3393 return ret;
3394}
3395
3396static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3397 struct btrfs_block_group *block_group,
3398 struct inode *inode,
3399 u64 ino)
3400{
3401 struct btrfs_root *root = fs_info->tree_root;
3402 struct btrfs_trans_handle *trans;
3403 int ret = 0;
3404
3405 if (inode)
3406 goto truncate;
3407
3408 inode = btrfs_iget(fs_info->sb, ino, root);
3409 if (IS_ERR(inode))
3410 return -ENOENT;
3411
3412truncate:
3413 ret = btrfs_check_trunc_cache_free_space(fs_info,
3414 &fs_info->global_block_rsv);
3415 if (ret)
3416 goto out;
3417
3418 trans = btrfs_join_transaction(root);
3419 if (IS_ERR(trans)) {
3420 ret = PTR_ERR(trans);
3421 goto out;
3422 }
3423
3424 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3425
3426 btrfs_end_transaction(trans);
3427 btrfs_btree_balance_dirty(fs_info);
3428out:
3429 iput(inode);
3430 return ret;
3431}
3432
3433/*
3434 * Locate the free space cache EXTENT_DATA in root tree leaf and delete the
3435 * cache inode, to avoid free space cache data extent blocking data relocation.
3436 */
3437static int delete_v1_space_cache(struct extent_buffer *leaf,
3438 struct btrfs_block_group *block_group,
3439 u64 data_bytenr)
3440{
3441 u64 space_cache_ino;
3442 struct btrfs_file_extent_item *ei;
3443 struct btrfs_key key;
3444 bool found = false;
3445 int i;
3446 int ret;
3447
3448 if (btrfs_header_owner(leaf) != BTRFS_ROOT_TREE_OBJECTID)
3449 return 0;
3450
3451 for (i = 0; i < btrfs_header_nritems(leaf); i++) {
3452 u8 type;
3453
3454 btrfs_item_key_to_cpu(leaf, &key, i);
3455 if (key.type != BTRFS_EXTENT_DATA_KEY)
3456 continue;
3457 ei = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
3458 type = btrfs_file_extent_type(leaf, ei);
3459
3460 if ((type == BTRFS_FILE_EXTENT_REG ||
3461 type == BTRFS_FILE_EXTENT_PREALLOC) &&
3462 btrfs_file_extent_disk_bytenr(leaf, ei) == data_bytenr) {
3463 found = true;
3464 space_cache_ino = key.objectid;
3465 break;
3466 }
3467 }
3468 if (!found)
3469 return -ENOENT;
3470 ret = delete_block_group_cache(leaf->fs_info, block_group, NULL,
3471 space_cache_ino);
3472 return ret;
3473}
3474
3475/*
3476 * helper to find all tree blocks that reference a given data extent
3477 */
3478static noinline_for_stack int add_data_references(struct reloc_control *rc,
3479 const struct btrfs_key *extent_key,
3480 struct btrfs_path *path,
3481 struct rb_root *blocks)
3482{
3483 struct btrfs_backref_walk_ctx ctx = { 0 };
3484 struct ulist_iterator leaf_uiter;
3485 struct ulist_node *ref_node = NULL;
3486 const u32 blocksize = rc->extent_root->fs_info->nodesize;
3487 int ret = 0;
3488
3489 btrfs_release_path(path);
3490
3491 ctx.bytenr = extent_key->objectid;
3492 ctx.skip_inode_ref_list = true;
3493 ctx.fs_info = rc->extent_root->fs_info;
3494
3495 ret = btrfs_find_all_leafs(&ctx);
3496 if (ret < 0)
3497 return ret;
3498
3499 ULIST_ITER_INIT(&leaf_uiter);
3500 while ((ref_node = ulist_next(ctx.refs, &leaf_uiter))) {
3501 struct btrfs_tree_parent_check check = { 0 };
3502 struct extent_buffer *eb;
3503
3504 eb = read_tree_block(ctx.fs_info, ref_node->val, &check);
3505 if (IS_ERR(eb)) {
3506 ret = PTR_ERR(eb);
3507 break;
3508 }
3509 ret = delete_v1_space_cache(eb, rc->block_group,
3510 extent_key->objectid);
3511 free_extent_buffer(eb);
3512 if (ret < 0)
3513 break;
3514 ret = __add_tree_block(rc, ref_node->val, blocksize, blocks);
3515 if (ret < 0)
3516 break;
3517 }
3518 if (ret < 0)
3519 free_block_list(blocks);
3520 ulist_free(ctx.refs);
3521 return ret;
3522}
3523
3524/*
3525 * helper to find next unprocessed extent
3526 */
3527static noinline_for_stack
3528int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3529 struct btrfs_key *extent_key)
3530{
3531 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3532 struct btrfs_key key;
3533 struct extent_buffer *leaf;
3534 u64 start, end, last;
3535 int ret;
3536
3537 last = rc->block_group->start + rc->block_group->length;
3538 while (1) {
3539 bool block_found;
3540
3541 cond_resched();
3542 if (rc->search_start >= last) {
3543 ret = 1;
3544 break;
3545 }
3546
3547 key.objectid = rc->search_start;
3548 key.type = BTRFS_EXTENT_ITEM_KEY;
3549 key.offset = 0;
3550
3551 path->search_commit_root = 1;
3552 path->skip_locking = 1;
3553 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3554 0, 0);
3555 if (ret < 0)
3556 break;
3557next:
3558 leaf = path->nodes[0];
3559 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3560 ret = btrfs_next_leaf(rc->extent_root, path);
3561 if (ret != 0)
3562 break;
3563 leaf = path->nodes[0];
3564 }
3565
3566 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3567 if (key.objectid >= last) {
3568 ret = 1;
3569 break;
3570 }
3571
3572 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3573 key.type != BTRFS_METADATA_ITEM_KEY) {
3574 path->slots[0]++;
3575 goto next;
3576 }
3577
3578 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3579 key.objectid + key.offset <= rc->search_start) {
3580 path->slots[0]++;
3581 goto next;
3582 }
3583
3584 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3585 key.objectid + fs_info->nodesize <=
3586 rc->search_start) {
3587 path->slots[0]++;
3588 goto next;
3589 }
3590
3591 block_found = find_first_extent_bit(&rc->processed_blocks,
3592 key.objectid, &start, &end,
3593 EXTENT_DIRTY, NULL);
3594
3595 if (block_found && start <= key.objectid) {
3596 btrfs_release_path(path);
3597 rc->search_start = end + 1;
3598 } else {
3599 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3600 rc->search_start = key.objectid + key.offset;
3601 else
3602 rc->search_start = key.objectid +
3603 fs_info->nodesize;
3604 memcpy(extent_key, &key, sizeof(key));
3605 return 0;
3606 }
3607 }
3608 btrfs_release_path(path);
3609 return ret;
3610}
3611
3612static void set_reloc_control(struct reloc_control *rc)
3613{
3614 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3615
3616 mutex_lock(&fs_info->reloc_mutex);
3617 fs_info->reloc_ctl = rc;
3618 mutex_unlock(&fs_info->reloc_mutex);
3619}
3620
3621static void unset_reloc_control(struct reloc_control *rc)
3622{
3623 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3624
3625 mutex_lock(&fs_info->reloc_mutex);
3626 fs_info->reloc_ctl = NULL;
3627 mutex_unlock(&fs_info->reloc_mutex);
3628}
3629
3630static noinline_for_stack
3631int prepare_to_relocate(struct reloc_control *rc)
3632{
3633 struct btrfs_trans_handle *trans;
3634 int ret;
3635
3636 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3637 BTRFS_BLOCK_RSV_TEMP);
3638 if (!rc->block_rsv)
3639 return -ENOMEM;
3640
3641 memset(&rc->cluster, 0, sizeof(rc->cluster));
3642 rc->search_start = rc->block_group->start;
3643 rc->extents_found = 0;
3644 rc->nodes_relocated = 0;
3645 rc->merging_rsv_size = 0;
3646 rc->reserved_bytes = 0;
3647 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3648 RELOCATION_RESERVED_NODES;
3649 ret = btrfs_block_rsv_refill(rc->extent_root->fs_info,
3650 rc->block_rsv, rc->block_rsv->size,
3651 BTRFS_RESERVE_FLUSH_ALL);
3652 if (ret)
3653 return ret;
3654
3655 rc->create_reloc_tree = true;
3656 set_reloc_control(rc);
3657
3658 trans = btrfs_join_transaction(rc->extent_root);
3659 if (IS_ERR(trans)) {
3660 unset_reloc_control(rc);
3661 /*
3662 * extent tree is not a ref_cow tree and has no reloc_root to
3663 * cleanup. And callers are responsible to free the above
3664 * block rsv.
3665 */
3666 return PTR_ERR(trans);
3667 }
3668
3669 ret = btrfs_commit_transaction(trans);
3670 if (ret)
3671 unset_reloc_control(rc);
3672
3673 return ret;
3674}
3675
3676static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
3677{
3678 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3679 struct rb_root blocks = RB_ROOT;
3680 struct btrfs_key key;
3681 struct btrfs_trans_handle *trans = NULL;
3682 struct btrfs_path *path;
3683 struct btrfs_extent_item *ei;
3684 u64 flags;
3685 int ret;
3686 int err = 0;
3687 int progress = 0;
3688
3689 path = btrfs_alloc_path();
3690 if (!path)
3691 return -ENOMEM;
3692 path->reada = READA_FORWARD;
3693
3694 ret = prepare_to_relocate(rc);
3695 if (ret) {
3696 err = ret;
3697 goto out_free;
3698 }
3699
3700 while (1) {
3701 rc->reserved_bytes = 0;
3702 ret = btrfs_block_rsv_refill(fs_info, rc->block_rsv,
3703 rc->block_rsv->size,
3704 BTRFS_RESERVE_FLUSH_ALL);
3705 if (ret) {
3706 err = ret;
3707 break;
3708 }
3709 progress++;
3710 trans = btrfs_start_transaction(rc->extent_root, 0);
3711 if (IS_ERR(trans)) {
3712 err = PTR_ERR(trans);
3713 trans = NULL;
3714 break;
3715 }
3716restart:
3717 if (update_backref_cache(trans, &rc->backref_cache)) {
3718 btrfs_end_transaction(trans);
3719 trans = NULL;
3720 continue;
3721 }
3722
3723 ret = find_next_extent(rc, path, &key);
3724 if (ret < 0)
3725 err = ret;
3726 if (ret != 0)
3727 break;
3728
3729 rc->extents_found++;
3730
3731 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
3732 struct btrfs_extent_item);
3733 flags = btrfs_extent_flags(path->nodes[0], ei);
3734
3735 /*
3736 * If we are relocating a simple quota owned extent item, we
3737 * need to note the owner on the reloc data root so that when
3738 * we allocate the replacement item, we can attribute it to the
3739 * correct eventual owner (rather than the reloc data root).
3740 */
3741 if (btrfs_qgroup_mode(fs_info) == BTRFS_QGROUP_MODE_SIMPLE) {
3742 struct btrfs_root *root = BTRFS_I(rc->data_inode)->root;
3743 u64 owning_root_id = btrfs_get_extent_owner_root(fs_info,
3744 path->nodes[0],
3745 path->slots[0]);
3746
3747 root->relocation_src_root = owning_root_id;
3748 }
3749
3750 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
3751 ret = add_tree_block(rc, &key, path, &blocks);
3752 } else if (rc->stage == UPDATE_DATA_PTRS &&
3753 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3754 ret = add_data_references(rc, &key, path, &blocks);
3755 } else {
3756 btrfs_release_path(path);
3757 ret = 0;
3758 }
3759 if (ret < 0) {
3760 err = ret;
3761 break;
3762 }
3763
3764 if (!RB_EMPTY_ROOT(&blocks)) {
3765 ret = relocate_tree_blocks(trans, rc, &blocks);
3766 if (ret < 0) {
3767 if (ret != -EAGAIN) {
3768 err = ret;
3769 break;
3770 }
3771 rc->extents_found--;
3772 rc->search_start = key.objectid;
3773 }
3774 }
3775
3776 btrfs_end_transaction_throttle(trans);
3777 btrfs_btree_balance_dirty(fs_info);
3778 trans = NULL;
3779
3780 if (rc->stage == MOVE_DATA_EXTENTS &&
3781 (flags & BTRFS_EXTENT_FLAG_DATA)) {
3782 rc->found_file_extent = true;
3783 ret = relocate_data_extent(rc->data_inode,
3784 &key, &rc->cluster);
3785 if (ret < 0) {
3786 err = ret;
3787 break;
3788 }
3789 }
3790 if (btrfs_should_cancel_balance(fs_info)) {
3791 err = -ECANCELED;
3792 break;
3793 }
3794 }
3795 if (trans && progress && err == -ENOSPC) {
3796 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
3797 if (ret == 1) {
3798 err = 0;
3799 progress = 0;
3800 goto restart;
3801 }
3802 }
3803
3804 btrfs_release_path(path);
3805 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
3806
3807 if (trans) {
3808 btrfs_end_transaction_throttle(trans);
3809 btrfs_btree_balance_dirty(fs_info);
3810 }
3811
3812 if (!err) {
3813 ret = relocate_file_extent_cluster(rc->data_inode,
3814 &rc->cluster);
3815 if (ret < 0)
3816 err = ret;
3817 }
3818
3819 rc->create_reloc_tree = false;
3820 set_reloc_control(rc);
3821
3822 btrfs_backref_release_cache(&rc->backref_cache);
3823 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3824
3825 /*
3826 * Even in the case when the relocation is cancelled, we should all go
3827 * through prepare_to_merge() and merge_reloc_roots().
3828 *
3829 * For error (including cancelled balance), prepare_to_merge() will
3830 * mark all reloc trees orphan, then queue them for cleanup in
3831 * merge_reloc_roots()
3832 */
3833 err = prepare_to_merge(rc, err);
3834
3835 merge_reloc_roots(rc);
3836
3837 rc->merge_reloc_tree = false;
3838 unset_reloc_control(rc);
3839 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1, NULL);
3840
3841 /* get rid of pinned extents */
3842 trans = btrfs_join_transaction(rc->extent_root);
3843 if (IS_ERR(trans)) {
3844 err = PTR_ERR(trans);
3845 goto out_free;
3846 }
3847 ret = btrfs_commit_transaction(trans);
3848 if (ret && !err)
3849 err = ret;
3850out_free:
3851 ret = clean_dirty_subvols(rc);
3852 if (ret < 0 && !err)
3853 err = ret;
3854 btrfs_free_block_rsv(fs_info, rc->block_rsv);
3855 btrfs_free_path(path);
3856 return err;
3857}
3858
3859static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
3860 struct btrfs_root *root, u64 objectid)
3861{
3862 struct btrfs_path *path;
3863 struct btrfs_inode_item *item;
3864 struct extent_buffer *leaf;
3865 int ret;
3866
3867 path = btrfs_alloc_path();
3868 if (!path)
3869 return -ENOMEM;
3870
3871 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
3872 if (ret)
3873 goto out;
3874
3875 leaf = path->nodes[0];
3876 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
3877 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
3878 btrfs_set_inode_generation(leaf, item, 1);
3879 btrfs_set_inode_size(leaf, item, 0);
3880 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
3881 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
3882 BTRFS_INODE_PREALLOC);
3883 btrfs_mark_buffer_dirty(trans, leaf);
3884out:
3885 btrfs_free_path(path);
3886 return ret;
3887}
3888
3889static void delete_orphan_inode(struct btrfs_trans_handle *trans,
3890 struct btrfs_root *root, u64 objectid)
3891{
3892 struct btrfs_path *path;
3893 struct btrfs_key key;
3894 int ret = 0;
3895
3896 path = btrfs_alloc_path();
3897 if (!path) {
3898 ret = -ENOMEM;
3899 goto out;
3900 }
3901
3902 key.objectid = objectid;
3903 key.type = BTRFS_INODE_ITEM_KEY;
3904 key.offset = 0;
3905 ret = btrfs_search_slot(trans, root, &key, path, -1, 1);
3906 if (ret) {
3907 if (ret > 0)
3908 ret = -ENOENT;
3909 goto out;
3910 }
3911 ret = btrfs_del_item(trans, root, path);
3912out:
3913 if (ret)
3914 btrfs_abort_transaction(trans, ret);
3915 btrfs_free_path(path);
3916}
3917
3918/*
3919 * helper to create inode for data relocation.
3920 * the inode is in data relocation tree and its link count is 0
3921 */
3922static noinline_for_stack struct inode *create_reloc_inode(
3923 struct btrfs_fs_info *fs_info,
3924 const struct btrfs_block_group *group)
3925{
3926 struct inode *inode = NULL;
3927 struct btrfs_trans_handle *trans;
3928 struct btrfs_root *root;
3929 u64 objectid;
3930 int err = 0;
3931
3932 root = btrfs_grab_root(fs_info->data_reloc_root);
3933 trans = btrfs_start_transaction(root, 6);
3934 if (IS_ERR(trans)) {
3935 btrfs_put_root(root);
3936 return ERR_CAST(trans);
3937 }
3938
3939 err = btrfs_get_free_objectid(root, &objectid);
3940 if (err)
3941 goto out;
3942
3943 err = __insert_orphan_inode(trans, root, objectid);
3944 if (err)
3945 goto out;
3946
3947 inode = btrfs_iget(fs_info->sb, objectid, root);
3948 if (IS_ERR(inode)) {
3949 delete_orphan_inode(trans, root, objectid);
3950 err = PTR_ERR(inode);
3951 inode = NULL;
3952 goto out;
3953 }
3954 BTRFS_I(inode)->index_cnt = group->start;
3955
3956 err = btrfs_orphan_add(trans, BTRFS_I(inode));
3957out:
3958 btrfs_put_root(root);
3959 btrfs_end_transaction(trans);
3960 btrfs_btree_balance_dirty(fs_info);
3961 if (err) {
3962 iput(inode);
3963 inode = ERR_PTR(err);
3964 }
3965 return inode;
3966}
3967
3968/*
3969 * Mark start of chunk relocation that is cancellable. Check if the cancellation
3970 * has been requested meanwhile and don't start in that case.
3971 *
3972 * Return:
3973 * 0 success
3974 * -EINPROGRESS operation is already in progress, that's probably a bug
3975 * -ECANCELED cancellation request was set before the operation started
3976 */
3977static int reloc_chunk_start(struct btrfs_fs_info *fs_info)
3978{
3979 if (test_and_set_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags)) {
3980 /* This should not happen */
3981 btrfs_err(fs_info, "reloc already running, cannot start");
3982 return -EINPROGRESS;
3983 }
3984
3985 if (atomic_read(&fs_info->reloc_cancel_req) > 0) {
3986 btrfs_info(fs_info, "chunk relocation canceled on start");
3987 /*
3988 * On cancel, clear all requests but let the caller mark
3989 * the end after cleanup operations.
3990 */
3991 atomic_set(&fs_info->reloc_cancel_req, 0);
3992 return -ECANCELED;
3993 }
3994 return 0;
3995}
3996
3997/*
3998 * Mark end of chunk relocation that is cancellable and wake any waiters.
3999 */
4000static void reloc_chunk_end(struct btrfs_fs_info *fs_info)
4001{
4002 /* Requested after start, clear bit first so any waiters can continue */
4003 if (atomic_read(&fs_info->reloc_cancel_req) > 0)
4004 btrfs_info(fs_info, "chunk relocation canceled during operation");
4005 clear_and_wake_up_bit(BTRFS_FS_RELOC_RUNNING, &fs_info->flags);
4006 atomic_set(&fs_info->reloc_cancel_req, 0);
4007}
4008
4009static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4010{
4011 struct reloc_control *rc;
4012
4013 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4014 if (!rc)
4015 return NULL;
4016
4017 INIT_LIST_HEAD(&rc->reloc_roots);
4018 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4019 btrfs_backref_init_cache(fs_info, &rc->backref_cache, true);
4020 rc->reloc_root_tree.rb_root = RB_ROOT;
4021 spin_lock_init(&rc->reloc_root_tree.lock);
4022 extent_io_tree_init(fs_info, &rc->processed_blocks, IO_TREE_RELOC_BLOCKS);
4023 return rc;
4024}
4025
4026static void free_reloc_control(struct reloc_control *rc)
4027{
4028 struct mapping_node *node, *tmp;
4029
4030 free_reloc_roots(&rc->reloc_roots);
4031 rbtree_postorder_for_each_entry_safe(node, tmp,
4032 &rc->reloc_root_tree.rb_root, rb_node)
4033 kfree(node);
4034
4035 kfree(rc);
4036}
4037
4038/*
4039 * Print the block group being relocated
4040 */
4041static void describe_relocation(struct btrfs_fs_info *fs_info,
4042 struct btrfs_block_group *block_group)
4043{
4044 char buf[128] = {'\0'};
4045
4046 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4047
4048 btrfs_info(fs_info,
4049 "relocating block group %llu flags %s",
4050 block_group->start, buf);
4051}
4052
4053static const char *stage_to_string(enum reloc_stage stage)
4054{
4055 if (stage == MOVE_DATA_EXTENTS)
4056 return "move data extents";
4057 if (stage == UPDATE_DATA_PTRS)
4058 return "update data pointers";
4059 return "unknown";
4060}
4061
4062/*
4063 * function to relocate all extents in a block group.
4064 */
4065int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4066{
4067 struct btrfs_block_group *bg;
4068 struct btrfs_root *extent_root = btrfs_extent_root(fs_info, group_start);
4069 struct reloc_control *rc;
4070 struct inode *inode;
4071 struct btrfs_path *path;
4072 int ret;
4073 int rw = 0;
4074 int err = 0;
4075
4076 /*
4077 * This only gets set if we had a half-deleted snapshot on mount. We
4078 * cannot allow relocation to start while we're still trying to clean up
4079 * these pending deletions.
4080 */
4081 ret = wait_on_bit(&fs_info->flags, BTRFS_FS_UNFINISHED_DROPS, TASK_INTERRUPTIBLE);
4082 if (ret)
4083 return ret;
4084
4085 /* We may have been woken up by close_ctree, so bail if we're closing. */
4086 if (btrfs_fs_closing(fs_info))
4087 return -EINTR;
4088
4089 bg = btrfs_lookup_block_group(fs_info, group_start);
4090 if (!bg)
4091 return -ENOENT;
4092
4093 /*
4094 * Relocation of a data block group creates ordered extents. Without
4095 * sb_start_write(), we can freeze the filesystem while unfinished
4096 * ordered extents are left. Such ordered extents can cause a deadlock
4097 * e.g. when syncfs() is waiting for their completion but they can't
4098 * finish because they block when joining a transaction, due to the
4099 * fact that the freeze locks are being held in write mode.
4100 */
4101 if (bg->flags & BTRFS_BLOCK_GROUP_DATA)
4102 ASSERT(sb_write_started(fs_info->sb));
4103
4104 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4105 btrfs_put_block_group(bg);
4106 return -ETXTBSY;
4107 }
4108
4109 rc = alloc_reloc_control(fs_info);
4110 if (!rc) {
4111 btrfs_put_block_group(bg);
4112 return -ENOMEM;
4113 }
4114
4115 ret = reloc_chunk_start(fs_info);
4116 if (ret < 0) {
4117 err = ret;
4118 goto out_put_bg;
4119 }
4120
4121 rc->extent_root = extent_root;
4122 rc->block_group = bg;
4123
4124 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4125 if (ret) {
4126 err = ret;
4127 goto out;
4128 }
4129 rw = 1;
4130
4131 path = btrfs_alloc_path();
4132 if (!path) {
4133 err = -ENOMEM;
4134 goto out;
4135 }
4136
4137 inode = lookup_free_space_inode(rc->block_group, path);
4138 btrfs_free_path(path);
4139
4140 if (!IS_ERR(inode))
4141 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4142 else
4143 ret = PTR_ERR(inode);
4144
4145 if (ret && ret != -ENOENT) {
4146 err = ret;
4147 goto out;
4148 }
4149
4150 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4151 if (IS_ERR(rc->data_inode)) {
4152 err = PTR_ERR(rc->data_inode);
4153 rc->data_inode = NULL;
4154 goto out;
4155 }
4156
4157 describe_relocation(fs_info, rc->block_group);
4158
4159 btrfs_wait_block_group_reservations(rc->block_group);
4160 btrfs_wait_nocow_writers(rc->block_group);
4161 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4162 rc->block_group->start,
4163 rc->block_group->length);
4164
4165 ret = btrfs_zone_finish(rc->block_group);
4166 WARN_ON(ret && ret != -EAGAIN);
4167
4168 while (1) {
4169 enum reloc_stage finishes_stage;
4170
4171 mutex_lock(&fs_info->cleaner_mutex);
4172 ret = relocate_block_group(rc);
4173 mutex_unlock(&fs_info->cleaner_mutex);
4174 if (ret < 0)
4175 err = ret;
4176
4177 finishes_stage = rc->stage;
4178 /*
4179 * We may have gotten ENOSPC after we already dirtied some
4180 * extents. If writeout happens while we're relocating a
4181 * different block group we could end up hitting the
4182 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4183 * btrfs_reloc_cow_block. Make sure we write everything out
4184 * properly so we don't trip over this problem, and then break
4185 * out of the loop if we hit an error.
4186 */
4187 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4188 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4189 (u64)-1);
4190 if (ret)
4191 err = ret;
4192 invalidate_mapping_pages(rc->data_inode->i_mapping,
4193 0, -1);
4194 rc->stage = UPDATE_DATA_PTRS;
4195 }
4196
4197 if (err < 0)
4198 goto out;
4199
4200 if (rc->extents_found == 0)
4201 break;
4202
4203 btrfs_info(fs_info, "found %llu extents, stage: %s",
4204 rc->extents_found, stage_to_string(finishes_stage));
4205 }
4206
4207 WARN_ON(rc->block_group->pinned > 0);
4208 WARN_ON(rc->block_group->reserved > 0);
4209 WARN_ON(rc->block_group->used > 0);
4210out:
4211 if (err && rw)
4212 btrfs_dec_block_group_ro(rc->block_group);
4213 iput(rc->data_inode);
4214out_put_bg:
4215 btrfs_put_block_group(bg);
4216 reloc_chunk_end(fs_info);
4217 free_reloc_control(rc);
4218 return err;
4219}
4220
4221static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4222{
4223 struct btrfs_fs_info *fs_info = root->fs_info;
4224 struct btrfs_trans_handle *trans;
4225 int ret, err;
4226
4227 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4228 if (IS_ERR(trans))
4229 return PTR_ERR(trans);
4230
4231 memset(&root->root_item.drop_progress, 0,
4232 sizeof(root->root_item.drop_progress));
4233 btrfs_set_root_drop_level(&root->root_item, 0);
4234 btrfs_set_root_refs(&root->root_item, 0);
4235 ret = btrfs_update_root(trans, fs_info->tree_root,
4236 &root->root_key, &root->root_item);
4237
4238 err = btrfs_end_transaction(trans);
4239 if (err)
4240 return err;
4241 return ret;
4242}
4243
4244/*
4245 * recover relocation interrupted by system crash.
4246 *
4247 * this function resumes merging reloc trees with corresponding fs trees.
4248 * this is important for keeping the sharing of tree blocks
4249 */
4250int btrfs_recover_relocation(struct btrfs_fs_info *fs_info)
4251{
4252 LIST_HEAD(reloc_roots);
4253 struct btrfs_key key;
4254 struct btrfs_root *fs_root;
4255 struct btrfs_root *reloc_root;
4256 struct btrfs_path *path;
4257 struct extent_buffer *leaf;
4258 struct reloc_control *rc = NULL;
4259 struct btrfs_trans_handle *trans;
4260 int ret;
4261 int err = 0;
4262
4263 path = btrfs_alloc_path();
4264 if (!path)
4265 return -ENOMEM;
4266 path->reada = READA_BACK;
4267
4268 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4269 key.type = BTRFS_ROOT_ITEM_KEY;
4270 key.offset = (u64)-1;
4271
4272 while (1) {
4273 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4274 path, 0, 0);
4275 if (ret < 0) {
4276 err = ret;
4277 goto out;
4278 }
4279 if (ret > 0) {
4280 if (path->slots[0] == 0)
4281 break;
4282 path->slots[0]--;
4283 }
4284 leaf = path->nodes[0];
4285 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4286 btrfs_release_path(path);
4287
4288 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4289 key.type != BTRFS_ROOT_ITEM_KEY)
4290 break;
4291
4292 reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
4293 if (IS_ERR(reloc_root)) {
4294 err = PTR_ERR(reloc_root);
4295 goto out;
4296 }
4297
4298 set_bit(BTRFS_ROOT_SHAREABLE, &reloc_root->state);
4299 list_add(&reloc_root->root_list, &reloc_roots);
4300
4301 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4302 fs_root = btrfs_get_fs_root(fs_info,
4303 reloc_root->root_key.offset, false);
4304 if (IS_ERR(fs_root)) {
4305 ret = PTR_ERR(fs_root);
4306 if (ret != -ENOENT) {
4307 err = ret;
4308 goto out;
4309 }
4310 ret = mark_garbage_root(reloc_root);
4311 if (ret < 0) {
4312 err = ret;
4313 goto out;
4314 }
4315 } else {
4316 btrfs_put_root(fs_root);
4317 }
4318 }
4319
4320 if (key.offset == 0)
4321 break;
4322
4323 key.offset--;
4324 }
4325 btrfs_release_path(path);
4326
4327 if (list_empty(&reloc_roots))
4328 goto out;
4329
4330 rc = alloc_reloc_control(fs_info);
4331 if (!rc) {
4332 err = -ENOMEM;
4333 goto out;
4334 }
4335
4336 ret = reloc_chunk_start(fs_info);
4337 if (ret < 0) {
4338 err = ret;
4339 goto out_end;
4340 }
4341
4342 rc->extent_root = btrfs_extent_root(fs_info, 0);
4343
4344 set_reloc_control(rc);
4345
4346 trans = btrfs_join_transaction(rc->extent_root);
4347 if (IS_ERR(trans)) {
4348 err = PTR_ERR(trans);
4349 goto out_unset;
4350 }
4351
4352 rc->merge_reloc_tree = true;
4353
4354 while (!list_empty(&reloc_roots)) {
4355 reloc_root = list_entry(reloc_roots.next,
4356 struct btrfs_root, root_list);
4357 list_del(&reloc_root->root_list);
4358
4359 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4360 list_add_tail(&reloc_root->root_list,
4361 &rc->reloc_roots);
4362 continue;
4363 }
4364
4365 fs_root = btrfs_get_fs_root(fs_info, reloc_root->root_key.offset,
4366 false);
4367 if (IS_ERR(fs_root)) {
4368 err = PTR_ERR(fs_root);
4369 list_add_tail(&reloc_root->root_list, &reloc_roots);
4370 btrfs_end_transaction(trans);
4371 goto out_unset;
4372 }
4373
4374 err = __add_reloc_root(reloc_root);
4375 ASSERT(err != -EEXIST);
4376 if (err) {
4377 list_add_tail(&reloc_root->root_list, &reloc_roots);
4378 btrfs_put_root(fs_root);
4379 btrfs_end_transaction(trans);
4380 goto out_unset;
4381 }
4382 fs_root->reloc_root = btrfs_grab_root(reloc_root);
4383 btrfs_put_root(fs_root);
4384 }
4385
4386 err = btrfs_commit_transaction(trans);
4387 if (err)
4388 goto out_unset;
4389
4390 merge_reloc_roots(rc);
4391
4392 unset_reloc_control(rc);
4393
4394 trans = btrfs_join_transaction(rc->extent_root);
4395 if (IS_ERR(trans)) {
4396 err = PTR_ERR(trans);
4397 goto out_clean;
4398 }
4399 err = btrfs_commit_transaction(trans);
4400out_clean:
4401 ret = clean_dirty_subvols(rc);
4402 if (ret < 0 && !err)
4403 err = ret;
4404out_unset:
4405 unset_reloc_control(rc);
4406out_end:
4407 reloc_chunk_end(fs_info);
4408 free_reloc_control(rc);
4409out:
4410 free_reloc_roots(&reloc_roots);
4411
4412 btrfs_free_path(path);
4413
4414 if (err == 0) {
4415 /* cleanup orphan inode in data relocation tree */
4416 fs_root = btrfs_grab_root(fs_info->data_reloc_root);
4417 ASSERT(fs_root);
4418 err = btrfs_orphan_cleanup(fs_root);
4419 btrfs_put_root(fs_root);
4420 }
4421 return err;
4422}
4423
4424/*
4425 * helper to add ordered checksum for data relocation.
4426 *
4427 * cloning checksum properly handles the nodatasum extents.
4428 * it also saves CPU time to re-calculate the checksum.
4429 */
4430int btrfs_reloc_clone_csums(struct btrfs_ordered_extent *ordered)
4431{
4432 struct btrfs_inode *inode = BTRFS_I(ordered->inode);
4433 struct btrfs_fs_info *fs_info = inode->root->fs_info;
4434 u64 disk_bytenr = ordered->file_offset + inode->index_cnt;
4435 struct btrfs_root *csum_root = btrfs_csum_root(fs_info, disk_bytenr);
4436 LIST_HEAD(list);
4437 int ret;
4438
4439 ret = btrfs_lookup_csums_list(csum_root, disk_bytenr,
4440 disk_bytenr + ordered->num_bytes - 1,
4441 &list, 0, false);
4442 if (ret)
4443 return ret;
4444
4445 while (!list_empty(&list)) {
4446 struct btrfs_ordered_sum *sums =
4447 list_entry(list.next, struct btrfs_ordered_sum, list);
4448
4449 list_del_init(&sums->list);
4450
4451 /*
4452 * We need to offset the new_bytenr based on where the csum is.
4453 * We need to do this because we will read in entire prealloc
4454 * extents but we may have written to say the middle of the
4455 * prealloc extent, so we need to make sure the csum goes with
4456 * the right disk offset.
4457 *
4458 * We can do this because the data reloc inode refers strictly
4459 * to the on disk bytes, so we don't have to worry about
4460 * disk_len vs real len like with real inodes since it's all
4461 * disk length.
4462 */
4463 sums->logical = ordered->disk_bytenr + sums->logical - disk_bytenr;
4464 btrfs_add_ordered_sum(ordered, sums);
4465 }
4466
4467 return 0;
4468}
4469
4470int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4471 struct btrfs_root *root,
4472 const struct extent_buffer *buf,
4473 struct extent_buffer *cow)
4474{
4475 struct btrfs_fs_info *fs_info = root->fs_info;
4476 struct reloc_control *rc;
4477 struct btrfs_backref_node *node;
4478 int first_cow = 0;
4479 int level;
4480 int ret = 0;
4481
4482 rc = fs_info->reloc_ctl;
4483 if (!rc)
4484 return 0;
4485
4486 BUG_ON(rc->stage == UPDATE_DATA_PTRS && btrfs_is_data_reloc_root(root));
4487
4488 level = btrfs_header_level(buf);
4489 if (btrfs_header_generation(buf) <=
4490 btrfs_root_last_snapshot(&root->root_item))
4491 first_cow = 1;
4492
4493 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4494 rc->create_reloc_tree) {
4495 WARN_ON(!first_cow && level == 0);
4496
4497 node = rc->backref_cache.path[level];
4498 BUG_ON(node->bytenr != buf->start &&
4499 node->new_bytenr != buf->start);
4500
4501 btrfs_backref_drop_node_buffer(node);
4502 atomic_inc(&cow->refs);
4503 node->eb = cow;
4504 node->new_bytenr = cow->start;
4505
4506 if (!node->pending) {
4507 list_move_tail(&node->list,
4508 &rc->backref_cache.pending[level]);
4509 node->pending = 1;
4510 }
4511
4512 if (first_cow)
4513 mark_block_processed(rc, node);
4514
4515 if (first_cow && level > 0)
4516 rc->nodes_relocated += buf->len;
4517 }
4518
4519 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4520 ret = replace_file_extents(trans, rc, root, cow);
4521 return ret;
4522}
4523
4524/*
4525 * called before creating snapshot. it calculates metadata reservation
4526 * required for relocating tree blocks in the snapshot
4527 */
4528void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4529 u64 *bytes_to_reserve)
4530{
4531 struct btrfs_root *root = pending->root;
4532 struct reloc_control *rc = root->fs_info->reloc_ctl;
4533
4534 if (!rc || !have_reloc_root(root))
4535 return;
4536
4537 if (!rc->merge_reloc_tree)
4538 return;
4539
4540 root = root->reloc_root;
4541 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4542 /*
4543 * relocation is in the stage of merging trees. the space
4544 * used by merging a reloc tree is twice the size of
4545 * relocated tree nodes in the worst case. half for cowing
4546 * the reloc tree, half for cowing the fs tree. the space
4547 * used by cowing the reloc tree will be freed after the
4548 * tree is dropped. if we create snapshot, cowing the fs
4549 * tree may use more space than it frees. so we need
4550 * reserve extra space.
4551 */
4552 *bytes_to_reserve += rc->nodes_relocated;
4553}
4554
4555/*
4556 * called after snapshot is created. migrate block reservation
4557 * and create reloc root for the newly created snapshot
4558 *
4559 * This is similar to btrfs_init_reloc_root(), we come out of here with two
4560 * references held on the reloc_root, one for root->reloc_root and one for
4561 * rc->reloc_roots.
4562 */
4563int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4564 struct btrfs_pending_snapshot *pending)
4565{
4566 struct btrfs_root *root = pending->root;
4567 struct btrfs_root *reloc_root;
4568 struct btrfs_root *new_root;
4569 struct reloc_control *rc = root->fs_info->reloc_ctl;
4570 int ret;
4571
4572 if (!rc || !have_reloc_root(root))
4573 return 0;
4574
4575 rc = root->fs_info->reloc_ctl;
4576 rc->merging_rsv_size += rc->nodes_relocated;
4577
4578 if (rc->merge_reloc_tree) {
4579 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4580 rc->block_rsv,
4581 rc->nodes_relocated, true);
4582 if (ret)
4583 return ret;
4584 }
4585
4586 new_root = pending->snap;
4587 reloc_root = create_reloc_root(trans, root->reloc_root,
4588 new_root->root_key.objectid);
4589 if (IS_ERR(reloc_root))
4590 return PTR_ERR(reloc_root);
4591
4592 ret = __add_reloc_root(reloc_root);
4593 ASSERT(ret != -EEXIST);
4594 if (ret) {
4595 /* Pairs with create_reloc_root */
4596 btrfs_put_root(reloc_root);
4597 return ret;
4598 }
4599 new_root->reloc_root = btrfs_grab_root(reloc_root);
4600
4601 if (rc->create_reloc_tree)
4602 ret = clone_backref_node(trans, rc, root, reloc_root);
4603 return ret;
4604}
4605
4606/*
4607 * Get the current bytenr for the block group which is being relocated.
4608 *
4609 * Return U64_MAX if no running relocation.
4610 */
4611u64 btrfs_get_reloc_bg_bytenr(const struct btrfs_fs_info *fs_info)
4612{
4613 u64 logical = U64_MAX;
4614
4615 lockdep_assert_held(&fs_info->reloc_mutex);
4616
4617 if (fs_info->reloc_ctl && fs_info->reloc_ctl->block_group)
4618 logical = fs_info->reloc_ctl->block_group->start;
4619 return logical;
4620}