1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2009 Oracle. All rights reserved.
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>
14 #include "transaction.h"
17 #include "btrfs_inode.h"
18 #include "async-thread.h"
19 #include "free-space-cache.h"
20 #include "inode-map.h"
22 #include "print-tree.h"
23 #include "delalloc-space.h"
24 #include "block-group.h"
27 * backref_node, mapping_node and tree_block start with this
30 struct rb_node rb_node;
35 * present a tree block in the backref cache
38 struct rb_node rb_node;
42 /* objectid of tree block owner, can be not uptodate */
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 */
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;
67 * 1 if corresponding block has been cowed but some upper
68 * level block pointers may not point to the new location
70 unsigned int pending:1;
72 * 1 if the backref node isn't connected to any other
75 unsigned int detached:1;
79 * present a block pointer in the backref cache
82 struct list_head list[2];
83 struct backref_node *node[2];
88 #define RELOCATION_RESERVED_NODES 256
90 struct backref_cache {
91 /* red black tree of all backref nodes in the cache */
92 struct rb_root rb_root;
93 /* for passing backref nodes to btrfs_reloc_cow_block */
94 struct backref_node *path[BTRFS_MAX_LEVEL];
96 * list of blocks that have been cowed but some block
97 * pointers in upper level blocks may not reflect the
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;
115 * map address of tree root to tree
117 struct mapping_node {
118 struct rb_node rb_node;
123 struct mapping_tree {
124 struct rb_root rb_root;
129 * present a tree block to process
132 struct rb_node rb_node;
134 struct btrfs_key key;
135 unsigned int level:8;
136 unsigned int key_ready:1;
139 #define MAX_EXTENTS 128
141 struct file_extent_cluster {
144 u64 boundary[MAX_EXTENTS];
148 struct reloc_control {
149 /* block group to relocate */
150 struct btrfs_block_group_cache *block_group;
152 struct btrfs_root *extent_root;
153 /* inode for moving data */
154 struct inode *data_inode;
156 struct btrfs_block_rsv *block_rsv;
158 struct backref_cache backref_cache;
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 */
173 /* reserved size for block group relocation*/
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;
185 /* stages of data relocation */
186 #define MOVE_DATA_EXTENTS 0
187 #define UPDATE_DATA_PTRS 1
189 static void remove_backref_node(struct backref_cache *cache,
190 struct backref_node *node);
191 static void __mark_block_processed(struct reloc_control *rc,
192 struct backref_node *node);
194 static void mapping_tree_init(struct mapping_tree *tree)
196 tree->rb_root = RB_ROOT;
197 spin_lock_init(&tree->lock);
200 static void backref_cache_init(struct backref_cache *cache)
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);
211 static void backref_cache_cleanup(struct backref_cache *cache)
213 struct backref_node *node;
216 while (!list_empty(&cache->detached)) {
217 node = list_entry(cache->detached.next,
218 struct backref_node, list);
219 remove_backref_node(cache, node);
222 while (!list_empty(&cache->leaves)) {
223 node = list_entry(cache->leaves.next,
224 struct backref_node, lower);
225 remove_backref_node(cache, node);
228 cache->last_trans = 0;
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);
239 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
241 struct backref_node *node;
243 node = kzalloc(sizeof(*node), GFP_NOFS);
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);
254 static void free_backref_node(struct backref_cache *cache,
255 struct backref_node *node)
263 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
265 struct backref_edge *edge;
267 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 static void free_backref_edge(struct backref_cache *cache,
274 struct backref_edge *edge)
282 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
283 struct rb_node *node)
285 struct rb_node **p = &root->rb_node;
286 struct rb_node *parent = NULL;
287 struct tree_entry *entry;
291 entry = rb_entry(parent, struct tree_entry, rb_node);
293 if (bytenr < entry->bytenr)
295 else if (bytenr > entry->bytenr)
301 rb_link_node(node, parent, p);
302 rb_insert_color(node, root);
306 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
308 struct rb_node *n = root->rb_node;
309 struct tree_entry *entry;
312 entry = rb_entry(n, struct tree_entry, rb_node);
314 if (bytenr < entry->bytenr)
316 else if (bytenr > entry->bytenr)
324 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
327 struct btrfs_fs_info *fs_info = NULL;
328 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
331 fs_info = bnode->root->fs_info;
332 btrfs_panic(fs_info, errno,
333 "Inconsistency in backref cache found at offset %llu",
338 * walk up backref nodes until reach node presents tree root
340 static struct backref_node *walk_up_backref(struct backref_node *node,
341 struct backref_edge *edges[],
344 struct backref_edge *edge;
347 while (!list_empty(&node->upper)) {
348 edge = list_entry(node->upper.next,
349 struct backref_edge, list[LOWER]);
351 node = edge->node[UPPER];
353 BUG_ON(node->detached);
359 * walk down backref nodes to find start of next reference path
361 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
364 struct backref_edge *edge;
365 struct backref_node *lower;
369 edge = edges[idx - 1];
370 lower = edge->node[LOWER];
371 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
375 edge = list_entry(edge->list[LOWER].next,
376 struct backref_edge, list[LOWER]);
377 edges[idx - 1] = edge;
379 return edge->node[UPPER];
385 static void unlock_node_buffer(struct backref_node *node)
388 btrfs_tree_unlock(node->eb);
393 static void drop_node_buffer(struct backref_node *node)
396 unlock_node_buffer(node);
397 free_extent_buffer(node->eb);
402 static void drop_backref_node(struct backref_cache *tree,
403 struct backref_node *node)
405 BUG_ON(!list_empty(&node->upper));
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);
416 * remove a backref node from the backref cache
418 static void remove_backref_node(struct backref_cache *cache,
419 struct backref_node *node)
421 struct backref_node *upper;
422 struct backref_edge *edge;
427 BUG_ON(!node->lowest && !node->detached);
428 while (!list_empty(&node->upper)) {
429 edge = list_entry(node->upper.next, struct backref_edge,
431 upper = edge->node[UPPER];
432 list_del(&edge->list[LOWER]);
433 list_del(&edge->list[UPPER]);
434 free_backref_edge(cache, edge);
436 if (RB_EMPTY_NODE(&upper->rb_node)) {
437 BUG_ON(!list_empty(&node->upper));
438 drop_backref_node(cache, node);
444 * add the node to leaf node list if no other
445 * child block cached.
447 if (list_empty(&upper->lower)) {
448 list_add_tail(&upper->lower, &cache->leaves);
453 drop_backref_node(cache, node);
456 static void update_backref_node(struct backref_cache *cache,
457 struct backref_node *node, u64 bytenr)
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);
464 backref_tree_panic(rb_node, -EEXIST, bytenr);
468 * update backref cache after a transaction commit
470 static int update_backref_cache(struct btrfs_trans_handle *trans,
471 struct backref_cache *cache)
473 struct backref_node *node;
476 if (cache->last_trans == 0) {
477 cache->last_trans = trans->transid;
481 if (cache->last_trans == trans->transid)
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.
489 while (!list_empty(&cache->detached)) {
490 node = list_entry(cache->detached.next,
491 struct backref_node, list);
492 remove_backref_node(cache, node);
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);
504 * some nodes can be left in the pending list if there were
505 * errors during processing the pending nodes.
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)
512 update_backref_node(cache, node, node->new_bytenr);
516 cache->last_trans = 0;
521 static int should_ignore_root(struct btrfs_root *root)
523 struct btrfs_root *reloc_root;
525 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
528 reloc_root = root->reloc_root;
532 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
533 root->fs_info->running_transaction->transid - 1)
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
544 * find reloc tree by address of tree root
546 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
549 struct rb_node *rb_node;
550 struct mapping_node *node;
551 struct btrfs_root *root = NULL;
553 spin_lock(&rc->reloc_root_tree.lock);
554 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
556 node = rb_entry(rb_node, struct mapping_node, rb_node);
557 root = (struct btrfs_root *)node->data;
559 spin_unlock(&rc->reloc_root_tree.lock);
563 static int is_cowonly_root(u64 root_objectid)
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)
578 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
581 struct btrfs_key key;
583 key.objectid = root_objectid;
584 key.type = BTRFS_ROOT_ITEM_KEY;
585 if (is_cowonly_root(root_objectid))
588 key.offset = (u64)-1;
590 return btrfs_get_fs_root(fs_info, &key, false);
593 static noinline_for_stack
594 int find_inline_backref(struct extent_buffer *leaf, int slot,
595 unsigned long *ptr, unsigned long *end)
597 struct btrfs_key key;
598 struct btrfs_extent_item *ei;
599 struct btrfs_tree_block_info *bi;
602 btrfs_item_key_to_cpu(leaf, &key, slot);
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);
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));
614 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
615 item_size <= sizeof(*ei) + sizeof(*bi)) {
616 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
619 if (key.type == BTRFS_METADATA_ITEM_KEY &&
620 item_size <= sizeof(*ei)) {
621 WARN_ON(item_size < sizeof(*ei));
625 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
626 bi = (struct btrfs_tree_block_info *)(ei + 1);
627 *ptr = (unsigned long)(bi + 1);
629 *ptr = (unsigned long)(ei + 1);
631 *end = (unsigned long)ei + item_size;
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.
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.
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.
649 static noinline_for_stack
650 struct backref_node *build_backref_tree(struct reloc_control *rc,
651 struct btrfs_key *node_key,
652 int level, u64 bytenr)
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;
669 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
674 bool need_check = true;
676 path1 = btrfs_alloc_path();
677 path2 = btrfs_alloc_path();
678 if (!path1 || !path2) {
682 path1->reada = READA_FORWARD;
683 path2->reada = READA_FORWARD;
685 node = alloc_backref_node(cache);
691 node->bytenr = bytenr;
698 key.objectid = cur->bytenr;
699 key.type = BTRFS_METADATA_ITEM_KEY;
700 key.offset = (u64)-1;
702 path1->search_commit_root = 1;
703 path1->skip_locking = 1;
704 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
711 ASSERT(path1->slots[0]);
715 WARN_ON(cur->checked);
716 if (!list_empty(&cur->upper)) {
718 * the backref was added previously when processing
719 * backref of type BTRFS_TREE_BLOCK_REF_KEY
721 ASSERT(list_is_singular(&cur->upper));
722 edge = list_entry(cur->upper.next, struct backref_edge,
724 ASSERT(list_empty(&edge->list[UPPER]));
725 exist = edge->node[UPPER];
727 * add the upper level block to pending list if we need
731 list_add_tail(&edge->list[UPPER], &list);
738 eb = path1->nodes[0];
741 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
742 ret = btrfs_next_leaf(rc->extent_root, path1);
749 eb = path1->nodes[0];
752 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
753 if (key.objectid != cur->bytenr) {
758 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
759 key.type == BTRFS_METADATA_ITEM_KEY) {
760 ret = find_inline_backref(eb, path1->slots[0],
768 /* update key for inline back ref */
769 struct btrfs_extent_inline_ref *iref;
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) {
779 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
781 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
782 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
786 * Parent node found and matches current inline ref, no need to
787 * rebuild this node for this inline ref.
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))) {
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) {
802 * Only root blocks of reloc trees use backref
803 * pointing to itself.
805 root = find_reloc_root(rc, cur->bytenr);
811 edge = alloc_backref_edge(cache);
816 rb_node = tree_search(&cache->rb_root, key.offset);
818 upper = alloc_backref_node(cache);
820 free_backref_edge(cache, edge);
824 upper->bytenr = key.offset;
825 upper->level = cur->level + 1;
827 * backrefs for the upper level block isn't
828 * cached, add the block to pending list
830 list_add_tail(&edge->list[UPPER], &list);
832 upper = rb_entry(rb_node, struct backref_node,
834 ASSERT(upper->checked);
835 INIT_LIST_HEAD(&edge->list[UPPER]);
837 list_add_tail(&edge->list[LOWER], &cur->upper);
838 edge->node[LOWER] = cur;
839 edge->node[UPPER] = upper;
842 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
844 btrfs_print_v0_err(rc->extent_root->fs_info);
845 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
848 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
853 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
854 * means the root objectid. We need to search the tree to get
857 root = read_fs_root(rc->extent_root->fs_info, key.offset);
863 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
866 if (btrfs_root_level(&root->root_item) == cur->level) {
868 ASSERT(btrfs_root_bytenr(&root->root_item) ==
870 if (should_ignore_root(root))
871 list_add(&cur->list, &useless);
877 level = cur->level + 1;
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;
889 if (ret > 0 && path2->slots[level] > 0)
890 path2->slots[level]--;
892 eb = path2->nodes[level];
893 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
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,
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) ==
912 if (should_ignore_root(root))
913 list_add(&lower->list, &useless);
919 edge = alloc_backref_edge(cache);
925 eb = path2->nodes[level];
926 rb_node = tree_search(&cache->rb_root, eb->start);
928 upper = alloc_backref_node(cache);
930 free_backref_edge(cache, edge);
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,
942 * if we know the block isn't shared
943 * we can void checking its backrefs.
945 if (btrfs_block_can_be_shared(root, eb))
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.
956 if (!upper->checked && need_check) {
958 list_add_tail(&edge->list[UPPER],
963 INIT_LIST_HEAD(&edge->list[UPPER]);
966 upper = rb_entry(rb_node, struct backref_node,
968 ASSERT(upper->checked);
969 INIT_LIST_HEAD(&edge->list[UPPER]);
971 upper->owner = btrfs_header_owner(eb);
973 list_add_tail(&edge->list[LOWER], &lower->upper);
974 edge->node[LOWER] = lower;
975 edge->node[UPPER] = upper;
982 btrfs_release_path(path2);
985 ptr += btrfs_extent_inline_ref_size(key.type);
995 btrfs_release_path(path1);
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];
1009 * everything goes well, connect backref nodes and insert backref nodes
1012 ASSERT(node->checked);
1013 cowonly = node->cowonly;
1015 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1018 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1019 list_add_tail(&node->lower, &cache->leaves);
1022 list_for_each_entry(edge, &node->upper, list[LOWER])
1023 list_add_tail(&edge->list[UPPER], &list);
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);
1038 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1039 if (upper->lowest) {
1040 list_del_init(&upper->lower);
1044 list_add_tail(&edge->list[UPPER], &upper->lower);
1048 if (!upper->checked) {
1050 * Still want to blow up for developers since this is a
1057 if (cowonly != upper->cowonly) {
1064 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1067 backref_tree_panic(rb_node, -EEXIST,
1071 list_add_tail(&edge->list[UPPER], &upper->lower);
1073 list_for_each_entry(edge, &upper->upper, list[LOWER])
1074 list_add_tail(&edge->list[UPPER], &list);
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
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));
1088 if (upper->lowest) {
1089 list_del_init(&upper->lower);
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);
1100 if (list_empty(&lower->upper))
1101 list_add(&lower->list, &useless);
1103 __mark_block_processed(rc, upper);
1104 if (upper->level > 0) {
1105 list_add(&upper->list, &cache->detached);
1106 upper->detached = 1;
1108 rb_erase(&upper->rb_node, &cache->rb_root);
1109 free_backref_node(cache, upper);
1113 btrfs_free_path(path1);
1114 btrfs_free_path(path2);
1116 while (!list_empty(&useless)) {
1117 lower = list_entry(useless.next,
1118 struct backref_node, list);
1119 list_del_init(&lower->list);
1121 while (!list_empty(&list)) {
1122 edge = list_first_entry(&list, struct backref_edge,
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);
1131 * Lower is no longer linked to any upper backref nodes
1132 * and isn't in the cache, we can free it ourselves.
1134 if (list_empty(&lower->upper) &&
1135 RB_EMPTY_NODE(&lower->rb_node))
1136 list_add(&lower->list, &useless);
1138 if (!RB_EMPTY_NODE(&upper->rb_node))
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);
1148 while (!list_empty(&useless)) {
1149 lower = list_entry(useless.next,
1150 struct backref_node, list);
1151 list_del_init(&lower->list);
1154 free_backref_node(cache, lower);
1157 free_backref_node(cache, node);
1158 return ERR_PTR(err);
1160 ASSERT(!node || !node->detached);
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
1169 static int clone_backref_node(struct btrfs_trans_handle *trans,
1170 struct reloc_control *rc,
1171 struct btrfs_root *src,
1172 struct btrfs_root *dest)
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;
1182 if (cache->last_trans > 0)
1183 update_backref_cache(trans, cache);
1185 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1187 node = rb_entry(rb_node, struct backref_node, rb_node);
1191 BUG_ON(node->new_bytenr != reloc_root->node->start);
1195 rb_node = tree_search(&cache->rb_root,
1196 reloc_root->commit_root->start);
1198 node = rb_entry(rb_node, struct backref_node,
1200 BUG_ON(node->detached);
1207 new_node = alloc_backref_node(cache);
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;
1217 if (!node->lowest) {
1218 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1219 new_edge = alloc_backref_edge(cache);
1223 new_edge->node[UPPER] = new_node;
1224 new_edge->node[LOWER] = edge->node[LOWER];
1225 list_add_tail(&new_edge->list[UPPER],
1229 list_add_tail(&new_node->lower, &cache->leaves);
1232 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1233 &new_node->rb_node);
1235 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
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);
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);
1251 free_backref_node(cache, new_node);
1256 * helper to add 'address of tree root -> reloc tree' mapping
1258 static int __must_check __add_reloc_root(struct btrfs_root *root)
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;
1265 node = kmalloc(sizeof(*node), GFP_NOFS);
1269 node->bytenr = root->node->start;
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);
1277 btrfs_panic(fs_info, -EEXIST,
1278 "Duplicate root found for start=%llu while inserting into relocation tree",
1282 list_add_tail(&root->root_list, &rc->reloc_roots);
1287 * helper to delete the 'address of tree root -> reloc tree'
1290 static void __del_reloc_root(struct btrfs_root *root)
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;
1297 if (rc && root->node) {
1298 spin_lock(&rc->reloc_root_tree.lock);
1299 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1302 node = rb_entry(rb_node, struct mapping_node, rb_node);
1303 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1305 spin_unlock(&rc->reloc_root_tree.lock);
1308 BUG_ON((struct btrfs_root *)node->data != root);
1311 spin_lock(&fs_info->trans_lock);
1312 list_del_init(&root->root_list);
1313 spin_unlock(&fs_info->trans_lock);
1318 * helper to update the 'address of tree root -> reloc tree'
1321 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
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;
1328 spin_lock(&rc->reloc_root_tree.lock);
1329 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1332 node = rb_entry(rb_node, struct mapping_node, rb_node);
1333 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1335 spin_unlock(&rc->reloc_root_tree.lock);
1339 BUG_ON((struct btrfs_root *)node->data != root);
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);
1347 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1351 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1352 struct btrfs_root *root, u64 objectid)
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;
1361 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1364 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1365 root_key.type = BTRFS_ROOT_ITEM_KEY;
1366 root_key.offset = objectid;
1368 if (root->root_key.objectid == objectid) {
1369 u64 commit_root_gen;
1371 /* called by btrfs_init_reloc_root */
1372 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1373 BTRFS_TREE_RELOC_OBJECTID);
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.
1383 commit_root_gen = btrfs_header_generation(root->commit_root);
1384 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
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'.
1393 ret = btrfs_copy_root(trans, root, root->node, &eb,
1394 BTRFS_TREE_RELOC_OBJECTID);
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);
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;
1410 btrfs_tree_unlock(eb);
1411 free_extent_buffer(eb);
1413 ret = btrfs_insert_root(trans, fs_info->tree_root,
1414 &root_key, root_item);
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;
1425 * create reloc tree for a given fs tree. reloc tree is just a
1426 * snapshot of the fs tree with special root objectid.
1428 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1429 struct btrfs_root *root)
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;
1439 * The subvolume has reloc tree but the swap is finished, no need to
1440 * create/update the dead reloc tree
1442 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
1445 if (root->reloc_root) {
1446 reloc_root = root->reloc_root;
1447 reloc_root->last_trans = trans->transid;
1451 if (!rc || !rc->create_reloc_tree ||
1452 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1455 if (!trans->reloc_reserved) {
1456 rsv = trans->block_rsv;
1457 trans->block_rsv = rc->block_rsv;
1460 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1462 trans->block_rsv = rsv;
1464 ret = __add_reloc_root(reloc_root);
1466 root->reloc_root = reloc_root;
1471 * update root item of reloc tree
1473 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1474 struct btrfs_root *root)
1476 struct btrfs_fs_info *fs_info = root->fs_info;
1477 struct btrfs_root *reloc_root;
1478 struct btrfs_root_item *root_item;
1481 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1485 reloc_root = root->reloc_root;
1486 root_item = &reloc_root->root_item;
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);
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);
1501 ret = btrfs_update_root(trans, fs_info->tree_root,
1502 &reloc_root->root_key, root_item);
1510 * helper to find first cached inode with inode number >= objectid
1513 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1515 struct rb_node *node;
1516 struct rb_node *prev;
1517 struct btrfs_inode *entry;
1518 struct inode *inode;
1520 spin_lock(&root->inode_lock);
1522 node = root->inode_tree.rb_node;
1526 entry = rb_entry(node, struct btrfs_inode, rb_node);
1528 if (objectid < btrfs_ino(entry))
1529 node = node->rb_left;
1530 else if (objectid > btrfs_ino(entry))
1531 node = node->rb_right;
1537 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1538 if (objectid <= btrfs_ino(entry)) {
1542 prev = rb_next(prev);
1546 entry = rb_entry(node, struct btrfs_inode, rb_node);
1547 inode = igrab(&entry->vfs_inode);
1549 spin_unlock(&root->inode_lock);
1553 objectid = btrfs_ino(entry) + 1;
1554 if (cond_resched_lock(&root->inode_lock))
1557 node = rb_next(node);
1559 spin_unlock(&root->inode_lock);
1563 static int in_block_group(u64 bytenr,
1564 struct btrfs_block_group_cache *block_group)
1566 if (bytenr >= block_group->key.objectid &&
1567 bytenr < block_group->key.objectid + block_group->key.offset)
1573 * get new location of data
1575 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1576 u64 bytenr, u64 num_bytes)
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;
1584 path = btrfs_alloc_path();
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);
1598 leaf = path->nodes[0];
1599 fi = btrfs_item_ptr(leaf, path->slots[0],
1600 struct btrfs_file_extent_item);
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));
1607 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1612 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1615 btrfs_free_path(path);
1620 * update file extent items in the tree leaf to point to
1621 * the new locations.
1623 static noinline_for_stack
1624 int replace_file_extents(struct btrfs_trans_handle *trans,
1625 struct reloc_control *rc,
1626 struct btrfs_root *root,
1627 struct extent_buffer *leaf)
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;
1644 if (rc->stage != UPDATE_DATA_PTRS)
1647 /* reloc trees always use full backref */
1648 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1649 parent = leaf->start;
1653 nritems = btrfs_header_nritems(leaf);
1654 for (i = 0; i < nritems; i++) {
1655 struct btrfs_ref ref = { 0 };
1658 btrfs_item_key_to_cpu(leaf, &key, i);
1659 if (key.type != BTRFS_EXTENT_DATA_KEY)
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)
1665 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1666 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1669 if (!in_block_group(bytenr, rc->block_group))
1673 * if we are modifying block in fs tree, wait for readpage
1674 * to complete and drop the extent cache
1676 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1678 inode = find_next_inode(root, key.objectid);
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);
1684 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
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));
1691 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1696 btrfs_drop_extent_cache(BTRFS_I(inode),
1697 key.offset, end, 1);
1698 unlock_extent(&BTRFS_I(inode)->io_tree,
1703 ret = get_new_location(rc->data_inode, &new_bytenr,
1707 * Don't have to abort since we've not changed anything
1708 * in the file extent yet.
1713 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1716 key.offset -= btrfs_file_extent_offset(leaf, fi);
1717 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
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);
1724 btrfs_abort_transaction(trans, ret);
1728 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
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);
1735 btrfs_abort_transaction(trans, ret);
1740 btrfs_mark_buffer_dirty(leaf);
1742 btrfs_add_delayed_iput(inode);
1746 static noinline_for_stack
1747 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1748 struct btrfs_path *path, int level)
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));
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.
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.
1766 static noinline_for_stack
1767 int 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)
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;
1788 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1789 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1791 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1793 slot = path->slots[lowest_level];
1794 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1796 eb = btrfs_lock_root_node(dest);
1797 btrfs_set_lock_blocking_write(eb);
1798 level = btrfs_header_level(eb);
1800 if (level < lowest_level) {
1801 btrfs_tree_unlock(eb);
1802 free_extent_buffer(eb);
1807 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1810 btrfs_set_lock_blocking_write(eb);
1813 next_key->objectid = (u64)-1;
1814 next_key->type = (u8)-1;
1815 next_key->offset = (u64)-1;
1820 struct btrfs_key first_key;
1822 level = btrfs_header_level(parent);
1823 BUG_ON(level < lowest_level);
1825 ret = btrfs_bin_search(parent, &key, level, &slot);
1828 if (ret && slot > 0)
1831 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1832 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
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);
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]);
1850 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1855 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1856 memcmp_node_keys(parent, slot, path, level)) {
1857 if (level <= lowest_level) {
1862 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1863 level - 1, &first_key);
1867 } else if (!extent_buffer_uptodate(eb)) {
1869 free_extent_buffer(eb);
1872 btrfs_tree_lock(eb);
1874 ret = btrfs_cow_block(trans, dest, eb, parent,
1878 btrfs_set_lock_blocking_write(eb);
1880 btrfs_tree_unlock(parent);
1881 free_extent_buffer(parent);
1888 btrfs_tree_unlock(parent);
1889 free_extent_buffer(parent);
1894 btrfs_node_key_to_cpu(path->nodes[level], &key,
1895 path->slots[level]);
1896 btrfs_release_path(path);
1898 path->lowest_level = level;
1899 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1900 path->lowest_level = 0;
1904 * Info qgroup to trace both subtrees.
1906 * We must trace both trees.
1907 * 1) Tree reloc subtree
1908 * If not traced, we will leak data numbers
1910 * If not traced, we will double count old data
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.
1917 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1918 rc->block_group, parent, slot,
1919 path->nodes[level], path->slots[level],
1924 * swap blocks in fs tree and reloc tree.
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);
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]);
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);
1942 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
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);
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);
1956 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1958 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1959 ref.skip_qgroup = true;
1960 ret = btrfs_free_extent(trans, &ref);
1963 btrfs_unlock_up_safe(path, 0);
1968 btrfs_tree_unlock(parent);
1969 free_extent_buffer(parent);
1974 * helper to find next relocated block in reloc tree
1976 static noinline_for_stack
1977 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1980 struct extent_buffer *eb;
1985 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1987 for (i = 0; i < *level; i++) {
1988 free_extent_buffer(path->nodes[i]);
1989 path->nodes[i] = NULL;
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) {
1997 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2004 free_extent_buffer(path->nodes[i]);
2005 path->nodes[i] = NULL;
2011 * walk down reloc tree to find relocated block of lowest level
2013 static noinline_for_stack
2014 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2017 struct btrfs_fs_info *fs_info = root->fs_info;
2018 struct extent_buffer *eb = NULL;
2025 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2027 for (i = *level; i > 0; i--) {
2028 struct btrfs_key first_key;
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)
2038 if (path->slots[i] >= nritems) {
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,
2055 } else if (!extent_buffer_uptodate(eb)) {
2056 free_extent_buffer(eb);
2059 BUG_ON(btrfs_header_level(eb) != i - 1);
2060 path->nodes[i - 1] = eb;
2061 path->slots[i - 1] = 0;
2067 * invalidate extent cache for file extents whose key in range of
2068 * [min_key, max_key)
2070 static int invalidate_extent_cache(struct btrfs_root *root,
2071 struct btrfs_key *min_key,
2072 struct btrfs_key *max_key)
2074 struct btrfs_fs_info *fs_info = root->fs_info;
2075 struct inode *inode = NULL;
2080 objectid = min_key->objectid;
2085 if (objectid > max_key->objectid)
2088 inode = find_next_inode(root, objectid);
2091 ino = btrfs_ino(BTRFS_I(inode));
2093 if (ino > max_key->objectid) {
2099 if (!S_ISREG(inode->i_mode))
2102 if (unlikely(min_key->objectid == ino)) {
2103 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2105 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2108 start = min_key->offset;
2109 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2115 if (unlikely(max_key->objectid == ino)) {
2116 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2118 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2121 if (max_key->offset == 0)
2123 end = max_key->offset;
2124 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
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);
2139 static int find_next_key(struct btrfs_path *path, int level,
2140 struct btrfs_key *key)
2143 while (level < BTRFS_MAX_LEVEL) {
2144 if (!path->nodes[level])
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);
2158 * Insert current subvolume into reloc_control::dirty_subvol_roots
2160 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2161 struct reloc_control *rc,
2162 struct btrfs_root *root)
2164 struct btrfs_root *reloc_root = root->reloc_root;
2165 struct btrfs_root_item *reloc_root_item;
2167 /* @root must be a subvolume tree root with a valid reloc tree */
2168 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
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);
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);
2184 static int clean_dirty_subvols(struct reloc_control *rc)
2186 struct btrfs_root *root;
2187 struct btrfs_root *next;
2191 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
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;
2197 list_del_init(&root->reloc_dirty_list);
2198 root->reloc_root = NULL;
2201 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2202 if (ret2 < 0 && !ret)
2205 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2206 btrfs_put_fs_root(root);
2208 /* Orphan reloc tree, just clean it up */
2209 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2210 if (ret2 < 0 && !ret)
2218 * merge the relocated tree blocks in reloc tree with corresponding
2221 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2222 struct btrfs_root *root)
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;
2239 path = btrfs_alloc_path();
2242 path->reada = READA_FORWARD;
2244 reloc_root = root->reloc_root;
2245 root_item = &reloc_root->root_item;
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;
2253 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2255 level = root_item->drop_level;
2257 path->lowest_level = level;
2258 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2259 path->lowest_level = 0;
2261 btrfs_free_path(path);
2265 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2266 path->slots[level]);
2267 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2269 btrfs_unlock_up_safe(path, 0);
2272 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2273 memset(&next_key, 0, sizeof(next_key));
2276 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2277 BTRFS_RESERVE_FLUSH_ALL);
2282 trans = btrfs_start_transaction(root, 0);
2283 if (IS_ERR(trans)) {
2284 err = PTR_ERR(trans);
2288 trans->block_rsv = rc->block_rsv;
2293 ret = walk_down_reloc_tree(reloc_root, path, &level);
2301 if (!find_next_key(path, level, &key) &&
2302 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2305 ret = replace_path(trans, rc, root, reloc_root, path,
2306 &next_key, level, max_level);
2315 btrfs_node_key_to_cpu(path->nodes[level], &key,
2316 path->slots[level]);
2320 ret = walk_up_reloc_tree(reloc_root, path, &level);
2326 * save the merging progress in the drop_progress.
2327 * this is OK since root refs == 1 in this case.
2329 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2330 path->slots[level]);
2331 root_item->drop_level = level;
2333 btrfs_end_transaction_throttle(trans);
2336 btrfs_btree_balance_dirty(fs_info);
2338 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2339 invalidate_extent_cache(root, &key, &next_key);
2343 * handle the case only one block in the fs tree need to be
2344 * relocated and the block is tree root.
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);
2353 btrfs_free_path(path);
2356 insert_dirty_subvol(trans, rc, root);
2359 btrfs_end_transaction_throttle(trans);
2361 btrfs_btree_balance_dirty(fs_info);
2363 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2364 invalidate_extent_cache(root, &key, &next_key);
2369 static noinline_for_stack
2370 int prepare_to_merge(struct reloc_control *rc, int err)
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);
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);
2387 num_bytes = rc->merging_rsv_size;
2388 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2389 BTRFS_RESERVE_FLUSH_ALL);
2394 trans = btrfs_join_transaction(rc->extent_root);
2395 if (IS_ERR(trans)) {
2397 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2399 return PTR_ERR(trans);
2403 if (num_bytes != rc->merging_rsv_size) {
2404 btrfs_end_transaction(trans);
2405 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2411 rc->merge_reloc_tree = 1;
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);
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);
2423 * set reference count to 1, so btrfs_recover_relocation
2424 * knows it should resumes merging
2427 btrfs_set_root_refs(&reloc_root->root_item, 1);
2428 btrfs_update_reloc_root(trans, root);
2430 list_add(&reloc_root->root_list, &reloc_roots);
2433 list_splice(&reloc_roots, &rc->reloc_roots);
2436 btrfs_commit_transaction(trans);
2438 btrfs_end_transaction(trans);
2442 static noinline_for_stack
2443 void free_reloc_roots(struct list_head *list)
2445 struct btrfs_root *reloc_root;
2447 while (!list_empty(list)) {
2448 reloc_root = list_entry(list->next, struct btrfs_root,
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;
2458 static noinline_for_stack
2459 void merge_reloc_roots(struct reloc_control *rc)
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);
2468 root = rc->extent_root;
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
2476 mutex_lock(&fs_info->reloc_mutex);
2477 list_splice_init(&rc->reloc_roots, &reloc_roots);
2478 mutex_unlock(&fs_info->reloc_mutex);
2480 while (!list_empty(&reloc_roots)) {
2482 reloc_root = list_entry(reloc_roots.next,
2483 struct btrfs_root, root_list);
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);
2491 ret = merge_reloc_root(rc, root);
2493 if (list_empty(&reloc_root->root_list))
2494 list_add_tail(&reloc_root->root_list,
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);
2512 btrfs_handle_fs_error(fs_info, ret, NULL);
2513 if (!list_empty(&reloc_roots))
2514 free_reloc_roots(&reloc_roots);
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);
2524 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2527 static void free_block_list(struct rb_root *blocks)
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);
2538 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2539 struct btrfs_root *reloc_root)
2541 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2542 struct btrfs_root *root;
2544 if (reloc_root->last_trans == trans->transid)
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);
2551 return btrfs_record_root_in_trans(trans, root);
2554 static noinline_for_stack
2555 struct 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[])
2560 struct backref_node *next;
2561 struct btrfs_root *root;
2567 next = walk_up_backref(next, edges, &index);
2570 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2572 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2573 record_reloc_root_in_trans(trans, root);
2577 btrfs_record_root_in_trans(trans, root);
2578 root = root->reloc_root;
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;
2585 list_add_tail(&next->list,
2586 &rc->backref_cache.changed);
2587 __mark_block_processed(rc, next);
2593 next = walk_down_backref(edges, &index);
2594 if (!next || next->level <= node->level)
2601 /* setup backref node path for btrfs_reloc_cow_block */
2603 rc->backref_cache.path[next->level] = next;
2606 next = edges[index]->node[UPPER];
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.
2617 static noinline_for_stack
2618 struct btrfs_root *select_one_root(struct backref_node *node)
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];
2629 next = walk_up_backref(next, edges, &index);
2633 /* no other choice for non-references counted tree */
2634 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2637 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2643 next = walk_down_backref(edges, &index);
2644 if (!next || next->level <= node->level)
2649 return ERR_PTR(-ENOENT);
2653 static noinline_for_stack
2654 u64 calcu_metadata_size(struct reloc_control *rc,
2655 struct backref_node *node, int reserve)
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];
2664 BUG_ON(reserve && node->processed);
2669 if (next->processed && (reserve || next != node))
2672 num_bytes += fs_info->nodesize;
2674 if (list_empty(&next->upper))
2677 edge = list_entry(next->upper.next,
2678 struct backref_edge, list[LOWER]);
2679 edges[index++] = edge;
2680 next = edge->node[UPPER];
2682 next = walk_down_backref(edges, &index);
2687 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2688 struct reloc_control *rc,
2689 struct backref_node *node)
2691 struct btrfs_root *root = rc->extent_root;
2692 struct btrfs_fs_info *fs_info = root->fs_info;
2697 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2699 trans->block_rsv = rc->block_rsv;
2700 rc->reserved_bytes += num_bytes;
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.
2707 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2708 BTRFS_RESERVE_FLUSH_LIMIT);
2710 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2711 while (tmp <= rc->reserved_bytes)
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
2720 rc->block_rsv->size = tmp + fs_info->nodesize *
2721 RELOCATION_RESERVED_NODES;
2729 * relocate a block tree, and then update pointers in upper level
2730 * blocks that reference the block to point to the new location.
2732 * if called by link_to_upper, the block has already been relocated.
2733 * in that case this function just updates pointers.
2735 static 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)
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;
2754 BUG_ON(lowest && node->eb);
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 };
2764 upper = edge->node[UPPER];
2765 root = select_reloc_root(trans, rc, upper, edges);
2768 if (upper->eb && !upper->locked) {
2770 ret = btrfs_bin_search(upper->eb, key,
2771 upper->level, &slot);
2777 bytenr = btrfs_node_blockptr(upper->eb, slot);
2778 if (node->eb->start == bytenr)
2781 drop_node_buffer(upper);
2785 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2792 btrfs_release_path(path);
2797 upper->eb = path->nodes[upper->level];
2798 path->nodes[upper->level] = NULL;
2800 BUG_ON(upper->eb != path->nodes[upper->level]);
2804 path->locks[upper->level] = 0;
2806 slot = path->slots[upper->level];
2807 btrfs_release_path(path);
2809 ret = btrfs_bin_search(upper->eb, key, upper->level,
2818 bytenr = btrfs_node_blockptr(upper->eb, slot);
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,
2829 if (node->eb->start == bytenr)
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);
2841 } else if (!extent_buffer_uptodate(eb)) {
2842 free_extent_buffer(eb);
2846 btrfs_tree_lock(eb);
2847 btrfs_set_lock_blocking_write(eb);
2850 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2852 btrfs_tree_unlock(eb);
2853 free_extent_buffer(eb);
2858 BUG_ON(node->eb != eb);
2860 btrfs_set_node_blockptr(upper->eb, slot,
2862 btrfs_set_node_ptr_generation(upper->eb, slot,
2864 btrfs_mark_buffer_dirty(upper->eb);
2866 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2867 node->eb->start, blocksize,
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);
2875 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2879 if (!upper->pending)
2880 drop_node_buffer(upper);
2882 unlock_node_buffer(upper);
2887 if (!err && node->pending) {
2888 drop_node_buffer(node);
2889 list_move_tail(&node->list, &rc->backref_cache.changed);
2893 path->lowest_level = 0;
2894 BUG_ON(err == -ENOSPC);
2898 static int link_to_upper(struct btrfs_trans_handle *trans,
2899 struct reloc_control *rc,
2900 struct backref_node *node,
2901 struct btrfs_path *path)
2903 struct btrfs_key key;
2905 btrfs_node_key_to_cpu(node->eb, &key, 0);
2906 return do_relocation(trans, rc, node, &key, path, 0);
2909 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2910 struct reloc_control *rc,
2911 struct btrfs_path *path, int err)
2914 struct backref_cache *cache = &rc->backref_cache;
2915 struct backref_node *node;
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);
2927 ret = link_to_upper(trans, rc, node, path);
2932 list_splice_init(&list, &cache->pending[level]);
2937 static void mark_block_processed(struct reloc_control *rc,
2938 u64 bytenr, u32 blocksize)
2940 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2944 static void __mark_block_processed(struct reloc_control *rc,
2945 struct backref_node *node)
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);
2953 node->processed = 1;
2957 * mark a block and all blocks directly/indirectly reference the block
2960 static void update_processed_blocks(struct reloc_control *rc,
2961 struct backref_node *node)
2963 struct backref_node *next = node;
2964 struct backref_edge *edge;
2965 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2971 if (next->processed)
2974 __mark_block_processed(rc, next);
2976 if (list_empty(&next->upper))
2979 edge = list_entry(next->upper.next,
2980 struct backref_edge, list[LOWER]);
2981 edges[index++] = edge;
2982 next = edge->node[UPPER];
2984 next = walk_down_backref(edges, &index);
2988 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2990 u32 blocksize = rc->extent_root->fs_info->nodesize;
2992 if (test_range_bit(&rc->processed_blocks, bytenr,
2993 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2998 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2999 struct tree_block *block)
3001 struct extent_buffer *eb;
3003 BUG_ON(block->key_ready);
3004 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
3005 block->level, NULL);
3008 } else if (!extent_buffer_uptodate(eb)) {
3009 free_extent_buffer(eb);
3012 if (block->level == 0)
3013 btrfs_item_key_to_cpu(eb, &block->key, 0);
3015 btrfs_node_key_to_cpu(eb, &block->key, 0);
3016 free_extent_buffer(eb);
3017 block->key_ready = 1;
3022 * helper function to relocate a tree block
3024 static 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)
3030 struct btrfs_root *root;
3036 BUG_ON(node->processed);
3037 root = select_one_root(node);
3038 if (root == ERR_PTR(-ENOENT)) {
3039 update_processed_blocks(rc, node);
3043 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3044 ret = reserve_metadata_space(trans, rc, node);
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;
3057 list_add_tail(&node->list, &rc->backref_cache.changed);
3059 path->lowest_level = node->level;
3060 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3061 btrfs_release_path(path);
3066 update_processed_blocks(rc, node);
3068 ret = do_relocation(trans, rc, node, key, path, 1);
3071 if (ret || node->level == 0 || node->cowonly)
3072 remove_backref_node(&rc->backref_cache, node);
3077 * relocate a list of blocks
3079 static noinline_for_stack
3080 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3081 struct reloc_control *rc, struct rb_root *blocks)
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;
3091 path = btrfs_alloc_path();
3094 goto out_free_blocks;
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);
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);
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);
3117 err = PTR_ERR(node);
3121 ret = relocate_tree_block(trans, rc, node, &block->key,
3124 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3130 err = finish_pending_nodes(trans, rc, path, err);
3133 btrfs_free_path(path);
3135 free_block_list(blocks);
3139 static noinline_for_stack
3140 int prealloc_file_extent_cluster(struct inode *inode,
3141 struct file_extent_cluster *cluster)
3146 u64 offset = BTRFS_I(inode)->index_cnt;
3150 u64 prealloc_start = cluster->start - offset;
3151 u64 prealloc_end = cluster->end - offset;
3153 struct extent_changeset *data_reserved = NULL;
3155 BUG_ON(cluster->start != cluster->boundary[0]);
3158 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3159 prealloc_end + 1 - prealloc_start);
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;
3169 end = cluster->end - offset;
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);
3185 if (cur_offset < prealloc_end)
3186 btrfs_free_reserved_data_space(inode, data_reserved,
3187 cur_offset, prealloc_end + 1 - cur_offset);
3189 inode_unlock(inode);
3190 extent_changeset_free(data_reserved);
3194 static noinline_for_stack
3195 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
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;
3203 em = alloc_extent_map();
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);
3214 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
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);
3223 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3225 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3229 static int relocate_file_extent_cluster(struct inode *inode,
3230 struct file_extent_cluster *cluster)
3232 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3235 u64 offset = BTRFS_I(inode)->index_cnt;
3236 unsigned long index;
3237 unsigned long last_index;
3239 struct file_ra_state *ra;
3240 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3247 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3251 ret = prealloc_file_extent_cluster(inode, cluster);
3255 file_ra_state_init(ra, inode->i_mapping);
3257 ret = setup_extent_mapping(inode, cluster->start - offset,
3258 cluster->end - offset, cluster->start);
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),
3270 page = find_lock_page(inode->i_mapping, index);
3272 page_cache_sync_readahead(inode->i_mapping,
3274 last_index + 1 - index);
3275 page = find_or_create_page(inode->i_mapping, index,
3278 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3285 if (PageReadahead(page)) {
3286 page_cache_async_readahead(inode->i_mapping,
3287 ra, NULL, page, index,
3288 last_index + 1 - index);
3291 if (!PageUptodate(page)) {
3292 btrfs_readpage(NULL, page);
3294 if (!PageUptodate(page)) {
3297 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3299 btrfs_delalloc_release_extents(BTRFS_I(inode),
3306 page_start = page_offset(page);
3307 page_end = page_start + PAGE_SIZE - 1;
3309 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3311 set_page_extent_mapped(page);
3313 if (nr < cluster->nr &&
3314 page_start + offset == cluster->boundary[nr]) {
3315 set_extent_bits(&BTRFS_I(inode)->io_tree,
3316 page_start, page_end,
3321 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3326 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3328 btrfs_delalloc_release_extents(BTRFS_I(inode),
3331 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3332 page_start, page_end,
3333 EXTENT_LOCKED | EXTENT_BOUNDARY);
3337 set_page_dirty(page);
3339 unlock_extent(&BTRFS_I(inode)->io_tree,
3340 page_start, page_end);
3345 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3347 balance_dirty_pages_ratelimited(inode->i_mapping);
3348 btrfs_throttle(fs_info);
3350 WARN_ON(nr != cluster->nr);
3356 static noinline_for_stack
3357 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3358 struct file_extent_cluster *cluster)
3362 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3363 ret = relocate_file_extent_cluster(inode, cluster);
3370 cluster->start = extent_key->objectid;
3372 BUG_ON(cluster->nr >= MAX_EXTENTS);
3373 cluster->end = extent_key->objectid + extent_key->offset - 1;
3374 cluster->boundary[cluster->nr] = extent_key->objectid;
3377 if (cluster->nr >= MAX_EXTENTS) {
3378 ret = relocate_file_extent_cluster(inode, cluster);
3387 * helper to add a tree block to the list.
3388 * the major work is getting the generation and level of the block
3390 static int add_tree_block(struct reloc_control *rc,
3391 struct btrfs_key *extent_key,
3392 struct btrfs_path *path,
3393 struct rb_root *blocks)
3395 struct extent_buffer *eb;
3396 struct btrfs_extent_item *ei;
3397 struct btrfs_tree_block_info *bi;
3398 struct tree_block *block;
3399 struct rb_node *rb_node;
3404 eb = path->nodes[0];
3405 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3407 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3408 item_size >= sizeof(*ei) + sizeof(*bi)) {
3409 ei = btrfs_item_ptr(eb, path->slots[0],
3410 struct btrfs_extent_item);
3411 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3412 bi = (struct btrfs_tree_block_info *)(ei + 1);
3413 level = btrfs_tree_block_level(eb, bi);
3415 level = (int)extent_key->offset;
3417 generation = btrfs_extent_generation(eb, ei);
3418 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3419 btrfs_print_v0_err(eb->fs_info);
3420 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3426 btrfs_release_path(path);
3428 BUG_ON(level == -1);
3430 block = kmalloc(sizeof(*block), GFP_NOFS);
3434 block->bytenr = extent_key->objectid;
3435 block->key.objectid = rc->extent_root->fs_info->nodesize;
3436 block->key.offset = generation;
3437 block->level = level;
3438 block->key_ready = 0;
3440 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3442 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3448 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3450 static int __add_tree_block(struct reloc_control *rc,
3451 u64 bytenr, u32 blocksize,
3452 struct rb_root *blocks)
3454 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3455 struct btrfs_path *path;
3456 struct btrfs_key key;
3458 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3460 if (tree_block_processed(bytenr, rc))
3463 if (tree_search(blocks, bytenr))
3466 path = btrfs_alloc_path();
3470 key.objectid = bytenr;
3472 key.type = BTRFS_METADATA_ITEM_KEY;
3473 key.offset = (u64)-1;
3475 key.type = BTRFS_EXTENT_ITEM_KEY;
3476 key.offset = blocksize;
3479 path->search_commit_root = 1;
3480 path->skip_locking = 1;
3481 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3485 if (ret > 0 && skinny) {
3486 if (path->slots[0]) {
3488 btrfs_item_key_to_cpu(path->nodes[0], &key,
3490 if (key.objectid == bytenr &&
3491 (key.type == BTRFS_METADATA_ITEM_KEY ||
3492 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3493 key.offset == blocksize)))
3499 btrfs_release_path(path);
3505 btrfs_print_leaf(path->nodes[0]);
3507 "tree block extent item (%llu) is not found in extent tree",
3514 ret = add_tree_block(rc, &key, path, blocks);
3516 btrfs_free_path(path);
3521 * helper to check if the block use full backrefs for pointers in it
3523 static int block_use_full_backref(struct reloc_control *rc,
3524 struct extent_buffer *eb)
3529 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3530 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3533 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3534 eb->start, btrfs_header_level(eb), 1,
3538 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3545 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3546 struct btrfs_block_group_cache *block_group,
3547 struct inode *inode,
3550 struct btrfs_key key;
3551 struct btrfs_root *root = fs_info->tree_root;
3552 struct btrfs_trans_handle *trans;
3559 key.type = BTRFS_INODE_ITEM_KEY;
3562 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3567 ret = btrfs_check_trunc_cache_free_space(fs_info,
3568 &fs_info->global_block_rsv);
3572 trans = btrfs_join_transaction(root);
3573 if (IS_ERR(trans)) {
3574 ret = PTR_ERR(trans);
3578 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3580 btrfs_end_transaction(trans);
3581 btrfs_btree_balance_dirty(fs_info);
3588 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3589 * this function scans fs tree to find blocks reference the data extent
3591 static int find_data_references(struct reloc_control *rc,
3592 struct btrfs_key *extent_key,
3593 struct extent_buffer *leaf,
3594 struct btrfs_extent_data_ref *ref,
3595 struct rb_root *blocks)
3597 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3598 struct btrfs_path *path;
3599 struct tree_block *block;
3600 struct btrfs_root *root;
3601 struct btrfs_file_extent_item *fi;
3602 struct rb_node *rb_node;
3603 struct btrfs_key key;
3614 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3615 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3616 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3617 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3620 * This is an extent belonging to the free space cache, lets just delete
3621 * it and redo the search.
3623 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3624 ret = delete_block_group_cache(fs_info, rc->block_group,
3625 NULL, ref_objectid);
3631 path = btrfs_alloc_path();
3634 path->reada = READA_FORWARD;
3636 root = read_fs_root(fs_info, ref_root);
3638 err = PTR_ERR(root);
3642 key.objectid = ref_objectid;
3643 key.type = BTRFS_EXTENT_DATA_KEY;
3644 if (ref_offset > ((u64)-1 << 32))
3647 key.offset = ref_offset;
3649 path->search_commit_root = 1;
3650 path->skip_locking = 1;
3651 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3657 leaf = path->nodes[0];
3658 nritems = btrfs_header_nritems(leaf);
3660 * the references in tree blocks that use full backrefs
3661 * are not counted in
3663 if (block_use_full_backref(rc, leaf))
3667 rb_node = tree_search(blocks, leaf->start);
3672 path->slots[0] = nritems;
3675 while (ref_count > 0) {
3676 while (path->slots[0] >= nritems) {
3677 ret = btrfs_next_leaf(root, path);
3682 if (WARN_ON(ret > 0))
3685 leaf = path->nodes[0];
3686 nritems = btrfs_header_nritems(leaf);
3689 if (block_use_full_backref(rc, leaf))
3693 rb_node = tree_search(blocks, leaf->start);
3698 path->slots[0] = nritems;
3702 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3703 if (WARN_ON(key.objectid != ref_objectid ||
3704 key.type != BTRFS_EXTENT_DATA_KEY))
3707 fi = btrfs_item_ptr(leaf, path->slots[0],
3708 struct btrfs_file_extent_item);
3710 if (btrfs_file_extent_type(leaf, fi) ==
3711 BTRFS_FILE_EXTENT_INLINE)
3714 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3715 extent_key->objectid)
3718 key.offset -= btrfs_file_extent_offset(leaf, fi);
3719 if (key.offset != ref_offset)
3727 if (!tree_block_processed(leaf->start, rc)) {
3728 block = kmalloc(sizeof(*block), GFP_NOFS);
3733 block->bytenr = leaf->start;
3734 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3736 block->key_ready = 1;
3737 rb_node = tree_insert(blocks, block->bytenr,
3740 backref_tree_panic(rb_node, -EEXIST,
3746 path->slots[0] = nritems;
3752 btrfs_free_path(path);
3757 * helper to find all tree blocks that reference a given data extent
3759 static noinline_for_stack
3760 int add_data_references(struct reloc_control *rc,
3761 struct btrfs_key *extent_key,
3762 struct btrfs_path *path,
3763 struct rb_root *blocks)
3765 struct btrfs_key key;
3766 struct extent_buffer *eb;
3767 struct btrfs_extent_data_ref *dref;
3768 struct btrfs_extent_inline_ref *iref;
3771 u32 blocksize = rc->extent_root->fs_info->nodesize;
3775 eb = path->nodes[0];
3776 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3777 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3778 ptr += sizeof(struct btrfs_extent_item);
3781 iref = (struct btrfs_extent_inline_ref *)ptr;
3782 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3783 BTRFS_REF_TYPE_DATA);
3784 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3785 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3786 ret = __add_tree_block(rc, key.offset, blocksize,
3788 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3789 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3790 ret = find_data_references(rc, extent_key,
3794 btrfs_err(rc->extent_root->fs_info,
3795 "extent %llu slot %d has an invalid inline ref type",
3796 eb->start, path->slots[0]);
3802 ptr += btrfs_extent_inline_ref_size(key.type);
3808 eb = path->nodes[0];
3809 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3810 ret = btrfs_next_leaf(rc->extent_root, path);
3817 eb = path->nodes[0];
3820 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3821 if (key.objectid != extent_key->objectid)
3824 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3825 ret = __add_tree_block(rc, key.offset, blocksize,
3827 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3828 dref = btrfs_item_ptr(eb, path->slots[0],
3829 struct btrfs_extent_data_ref);
3830 ret = find_data_references(rc, extent_key,
3832 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3833 btrfs_print_v0_err(eb->fs_info);
3834 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3846 btrfs_release_path(path);
3848 free_block_list(blocks);
3853 * helper to find next unprocessed extent
3855 static noinline_for_stack
3856 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3857 struct btrfs_key *extent_key)
3859 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3860 struct btrfs_key key;
3861 struct extent_buffer *leaf;
3862 u64 start, end, last;
3865 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3868 if (rc->search_start >= last) {
3873 key.objectid = rc->search_start;
3874 key.type = BTRFS_EXTENT_ITEM_KEY;
3877 path->search_commit_root = 1;
3878 path->skip_locking = 1;
3879 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3884 leaf = path->nodes[0];
3885 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3886 ret = btrfs_next_leaf(rc->extent_root, path);
3889 leaf = path->nodes[0];
3892 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3893 if (key.objectid >= last) {
3898 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3899 key.type != BTRFS_METADATA_ITEM_KEY) {
3904 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3905 key.objectid + key.offset <= rc->search_start) {
3910 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3911 key.objectid + fs_info->nodesize <=
3917 ret = find_first_extent_bit(&rc->processed_blocks,
3918 key.objectid, &start, &end,
3919 EXTENT_DIRTY, NULL);
3921 if (ret == 0 && start <= key.objectid) {
3922 btrfs_release_path(path);
3923 rc->search_start = end + 1;
3925 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3926 rc->search_start = key.objectid + key.offset;
3928 rc->search_start = key.objectid +
3930 memcpy(extent_key, &key, sizeof(key));
3934 btrfs_release_path(path);
3938 static void set_reloc_control(struct reloc_control *rc)
3940 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3942 mutex_lock(&fs_info->reloc_mutex);
3943 fs_info->reloc_ctl = rc;
3944 mutex_unlock(&fs_info->reloc_mutex);
3947 static void unset_reloc_control(struct reloc_control *rc)
3949 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3951 mutex_lock(&fs_info->reloc_mutex);
3952 fs_info->reloc_ctl = NULL;
3953 mutex_unlock(&fs_info->reloc_mutex);
3956 static int check_extent_flags(u64 flags)
3958 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3959 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3961 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3962 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3964 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3965 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3970 static noinline_for_stack
3971 int prepare_to_relocate(struct reloc_control *rc)
3973 struct btrfs_trans_handle *trans;
3976 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3977 BTRFS_BLOCK_RSV_TEMP);
3981 memset(&rc->cluster, 0, sizeof(rc->cluster));
3982 rc->search_start = rc->block_group->key.objectid;
3983 rc->extents_found = 0;
3984 rc->nodes_relocated = 0;
3985 rc->merging_rsv_size = 0;
3986 rc->reserved_bytes = 0;
3987 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3988 RELOCATION_RESERVED_NODES;
3989 ret = btrfs_block_rsv_refill(rc->extent_root,
3990 rc->block_rsv, rc->block_rsv->size,
3991 BTRFS_RESERVE_FLUSH_ALL);
3995 rc->create_reloc_tree = 1;
3996 set_reloc_control(rc);
3998 trans = btrfs_join_transaction(rc->extent_root);
3999 if (IS_ERR(trans)) {
4000 unset_reloc_control(rc);
4002 * extent tree is not a ref_cow tree and has no reloc_root to
4003 * cleanup. And callers are responsible to free the above
4006 return PTR_ERR(trans);
4008 btrfs_commit_transaction(trans);
4012 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4014 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4015 struct rb_root blocks = RB_ROOT;
4016 struct btrfs_key key;
4017 struct btrfs_trans_handle *trans = NULL;
4018 struct btrfs_path *path;
4019 struct btrfs_extent_item *ei;
4026 path = btrfs_alloc_path();
4029 path->reada = READA_FORWARD;
4031 ret = prepare_to_relocate(rc);
4038 rc->reserved_bytes = 0;
4039 ret = btrfs_block_rsv_refill(rc->extent_root,
4040 rc->block_rsv, rc->block_rsv->size,
4041 BTRFS_RESERVE_FLUSH_ALL);
4047 trans = btrfs_start_transaction(rc->extent_root, 0);
4048 if (IS_ERR(trans)) {
4049 err = PTR_ERR(trans);
4054 if (update_backref_cache(trans, &rc->backref_cache)) {
4055 btrfs_end_transaction(trans);
4060 ret = find_next_extent(rc, path, &key);
4066 rc->extents_found++;
4068 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4069 struct btrfs_extent_item);
4070 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4071 if (item_size >= sizeof(*ei)) {
4072 flags = btrfs_extent_flags(path->nodes[0], ei);
4073 ret = check_extent_flags(flags);
4075 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4077 btrfs_print_v0_err(trans->fs_info);
4078 btrfs_abort_transaction(trans, err);
4084 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4085 ret = add_tree_block(rc, &key, path, &blocks);
4086 } else if (rc->stage == UPDATE_DATA_PTRS &&
4087 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4088 ret = add_data_references(rc, &key, path, &blocks);
4090 btrfs_release_path(path);
4098 if (!RB_EMPTY_ROOT(&blocks)) {
4099 ret = relocate_tree_blocks(trans, rc, &blocks);
4102 * if we fail to relocate tree blocks, force to update
4103 * backref cache when committing transaction.
4105 rc->backref_cache.last_trans = trans->transid - 1;
4107 if (ret != -EAGAIN) {
4111 rc->extents_found--;
4112 rc->search_start = key.objectid;
4116 btrfs_end_transaction_throttle(trans);
4117 btrfs_btree_balance_dirty(fs_info);
4120 if (rc->stage == MOVE_DATA_EXTENTS &&
4121 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4122 rc->found_file_extent = 1;
4123 ret = relocate_data_extent(rc->data_inode,
4124 &key, &rc->cluster);
4131 if (trans && progress && err == -ENOSPC) {
4132 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4140 btrfs_release_path(path);
4141 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4144 btrfs_end_transaction_throttle(trans);
4145 btrfs_btree_balance_dirty(fs_info);
4149 ret = relocate_file_extent_cluster(rc->data_inode,
4155 rc->create_reloc_tree = 0;
4156 set_reloc_control(rc);
4158 backref_cache_cleanup(&rc->backref_cache);
4159 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4161 err = prepare_to_merge(rc, err);
4163 merge_reloc_roots(rc);
4165 rc->merge_reloc_tree = 0;
4166 unset_reloc_control(rc);
4167 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4169 /* get rid of pinned extents */
4170 trans = btrfs_join_transaction(rc->extent_root);
4171 if (IS_ERR(trans)) {
4172 err = PTR_ERR(trans);
4175 btrfs_commit_transaction(trans);
4176 ret = clean_dirty_subvols(rc);
4177 if (ret < 0 && !err)
4180 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4181 btrfs_free_path(path);
4185 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4186 struct btrfs_root *root, u64 objectid)
4188 struct btrfs_path *path;
4189 struct btrfs_inode_item *item;
4190 struct extent_buffer *leaf;
4193 path = btrfs_alloc_path();
4197 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4201 leaf = path->nodes[0];
4202 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4203 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4204 btrfs_set_inode_generation(leaf, item, 1);
4205 btrfs_set_inode_size(leaf, item, 0);
4206 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4207 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4208 BTRFS_INODE_PREALLOC);
4209 btrfs_mark_buffer_dirty(leaf);
4211 btrfs_free_path(path);
4216 * helper to create inode for data relocation.
4217 * the inode is in data relocation tree and its link count is 0
4219 static noinline_for_stack
4220 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4221 struct btrfs_block_group_cache *group)
4223 struct inode *inode = NULL;
4224 struct btrfs_trans_handle *trans;
4225 struct btrfs_root *root;
4226 struct btrfs_key key;
4230 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4232 return ERR_CAST(root);
4234 trans = btrfs_start_transaction(root, 6);
4236 return ERR_CAST(trans);
4238 err = btrfs_find_free_objectid(root, &objectid);
4242 err = __insert_orphan_inode(trans, root, objectid);
4245 key.objectid = objectid;
4246 key.type = BTRFS_INODE_ITEM_KEY;
4248 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4249 BUG_ON(IS_ERR(inode));
4250 BTRFS_I(inode)->index_cnt = group->key.objectid;
4252 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4254 btrfs_end_transaction(trans);
4255 btrfs_btree_balance_dirty(fs_info);
4259 inode = ERR_PTR(err);
4264 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4266 struct reloc_control *rc;
4268 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4272 INIT_LIST_HEAD(&rc->reloc_roots);
4273 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4274 backref_cache_init(&rc->backref_cache);
4275 mapping_tree_init(&rc->reloc_root_tree);
4276 extent_io_tree_init(fs_info, &rc->processed_blocks,
4277 IO_TREE_RELOC_BLOCKS, NULL);
4282 * Print the block group being relocated
4284 static void describe_relocation(struct btrfs_fs_info *fs_info,
4285 struct btrfs_block_group_cache *block_group)
4287 char buf[128] = {'\0'};
4289 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4292 "relocating block group %llu flags %s",
4293 block_group->key.objectid, buf);
4297 * function to relocate all extents in a block group.
4299 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4301 struct btrfs_block_group_cache *bg;
4302 struct btrfs_root *extent_root = fs_info->extent_root;
4303 struct reloc_control *rc;
4304 struct inode *inode;
4305 struct btrfs_path *path;
4310 bg = btrfs_lookup_block_group(fs_info, group_start);
4314 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4315 btrfs_put_block_group(bg);
4319 rc = alloc_reloc_control(fs_info);
4321 btrfs_put_block_group(bg);
4325 rc->extent_root = extent_root;
4326 rc->block_group = bg;
4328 ret = btrfs_inc_block_group_ro(rc->block_group);
4335 path = btrfs_alloc_path();
4341 inode = lookup_free_space_inode(rc->block_group, path);
4342 btrfs_free_path(path);
4345 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4347 ret = PTR_ERR(inode);
4349 if (ret && ret != -ENOENT) {
4354 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4355 if (IS_ERR(rc->data_inode)) {
4356 err = PTR_ERR(rc->data_inode);
4357 rc->data_inode = NULL;
4361 describe_relocation(fs_info, rc->block_group);
4363 btrfs_wait_block_group_reservations(rc->block_group);
4364 btrfs_wait_nocow_writers(rc->block_group);
4365 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4366 rc->block_group->key.objectid,
4367 rc->block_group->key.offset);
4370 mutex_lock(&fs_info->cleaner_mutex);
4371 ret = relocate_block_group(rc);
4372 mutex_unlock(&fs_info->cleaner_mutex);
4377 * We may have gotten ENOSPC after we already dirtied some
4378 * extents. If writeout happens while we're relocating a
4379 * different block group we could end up hitting the
4380 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4381 * btrfs_reloc_cow_block. Make sure we write everything out
4382 * properly so we don't trip over this problem, and then break
4383 * out of the loop if we hit an error.
4385 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4386 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4390 invalidate_mapping_pages(rc->data_inode->i_mapping,
4392 rc->stage = UPDATE_DATA_PTRS;
4398 if (rc->extents_found == 0)
4401 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4405 WARN_ON(rc->block_group->pinned > 0);
4406 WARN_ON(rc->block_group->reserved > 0);
4407 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4410 btrfs_dec_block_group_ro(rc->block_group);
4411 iput(rc->data_inode);
4412 btrfs_put_block_group(rc->block_group);
4417 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4419 struct btrfs_fs_info *fs_info = root->fs_info;
4420 struct btrfs_trans_handle *trans;
4423 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4425 return PTR_ERR(trans);
4427 memset(&root->root_item.drop_progress, 0,
4428 sizeof(root->root_item.drop_progress));
4429 root->root_item.drop_level = 0;
4430 btrfs_set_root_refs(&root->root_item, 0);
4431 ret = btrfs_update_root(trans, fs_info->tree_root,
4432 &root->root_key, &root->root_item);
4434 err = btrfs_end_transaction(trans);
4441 * recover relocation interrupted by system crash.
4443 * this function resumes merging reloc trees with corresponding fs trees.
4444 * this is important for keeping the sharing of tree blocks
4446 int btrfs_recover_relocation(struct btrfs_root *root)
4448 struct btrfs_fs_info *fs_info = root->fs_info;
4449 LIST_HEAD(reloc_roots);
4450 struct btrfs_key key;
4451 struct btrfs_root *fs_root;
4452 struct btrfs_root *reloc_root;
4453 struct btrfs_path *path;
4454 struct extent_buffer *leaf;
4455 struct reloc_control *rc = NULL;
4456 struct btrfs_trans_handle *trans;
4460 path = btrfs_alloc_path();
4463 path->reada = READA_BACK;
4465 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4466 key.type = BTRFS_ROOT_ITEM_KEY;
4467 key.offset = (u64)-1;
4470 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4477 if (path->slots[0] == 0)
4481 leaf = path->nodes[0];
4482 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4483 btrfs_release_path(path);
4485 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4486 key.type != BTRFS_ROOT_ITEM_KEY)
4489 reloc_root = btrfs_read_fs_root(root, &key);
4490 if (IS_ERR(reloc_root)) {
4491 err = PTR_ERR(reloc_root);
4495 list_add(&reloc_root->root_list, &reloc_roots);
4497 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4498 fs_root = read_fs_root(fs_info,
4499 reloc_root->root_key.offset);
4500 if (IS_ERR(fs_root)) {
4501 ret = PTR_ERR(fs_root);
4502 if (ret != -ENOENT) {
4506 ret = mark_garbage_root(reloc_root);
4514 if (key.offset == 0)
4519 btrfs_release_path(path);
4521 if (list_empty(&reloc_roots))
4524 rc = alloc_reloc_control(fs_info);
4530 rc->extent_root = fs_info->extent_root;
4532 set_reloc_control(rc);
4534 trans = btrfs_join_transaction(rc->extent_root);
4535 if (IS_ERR(trans)) {
4536 unset_reloc_control(rc);
4537 err = PTR_ERR(trans);
4541 rc->merge_reloc_tree = 1;
4543 while (!list_empty(&reloc_roots)) {
4544 reloc_root = list_entry(reloc_roots.next,
4545 struct btrfs_root, root_list);
4546 list_del(&reloc_root->root_list);
4548 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4549 list_add_tail(&reloc_root->root_list,
4554 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4555 if (IS_ERR(fs_root)) {
4556 err = PTR_ERR(fs_root);
4560 err = __add_reloc_root(reloc_root);
4561 BUG_ON(err < 0); /* -ENOMEM or logic error */
4562 fs_root->reloc_root = reloc_root;
4565 err = btrfs_commit_transaction(trans);
4569 merge_reloc_roots(rc);
4571 unset_reloc_control(rc);
4573 trans = btrfs_join_transaction(rc->extent_root);
4574 if (IS_ERR(trans)) {
4575 err = PTR_ERR(trans);
4578 err = btrfs_commit_transaction(trans);
4580 ret = clean_dirty_subvols(rc);
4581 if (ret < 0 && !err)
4586 if (!list_empty(&reloc_roots))
4587 free_reloc_roots(&reloc_roots);
4589 btrfs_free_path(path);
4592 /* cleanup orphan inode in data relocation tree */
4593 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4594 if (IS_ERR(fs_root))
4595 err = PTR_ERR(fs_root);
4597 err = btrfs_orphan_cleanup(fs_root);
4603 * helper to add ordered checksum for data relocation.
4605 * cloning checksum properly handles the nodatasum extents.
4606 * it also saves CPU time to re-calculate the checksum.
4608 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4610 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4611 struct btrfs_ordered_sum *sums;
4612 struct btrfs_ordered_extent *ordered;
4618 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4619 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4621 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4622 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4623 disk_bytenr + len - 1, &list, 0);
4627 while (!list_empty(&list)) {
4628 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4629 list_del_init(&sums->list);
4632 * We need to offset the new_bytenr based on where the csum is.
4633 * We need to do this because we will read in entire prealloc
4634 * extents but we may have written to say the middle of the
4635 * prealloc extent, so we need to make sure the csum goes with
4636 * the right disk offset.
4638 * We can do this because the data reloc inode refers strictly
4639 * to the on disk bytes, so we don't have to worry about
4640 * disk_len vs real len like with real inodes since it's all
4643 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4644 sums->bytenr = new_bytenr;
4646 btrfs_add_ordered_sum(ordered, sums);
4649 btrfs_put_ordered_extent(ordered);
4653 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4654 struct btrfs_root *root, struct extent_buffer *buf,
4655 struct extent_buffer *cow)
4657 struct btrfs_fs_info *fs_info = root->fs_info;
4658 struct reloc_control *rc;
4659 struct backref_node *node;
4664 rc = fs_info->reloc_ctl;
4668 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4669 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4671 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4672 if (buf == root->node)
4673 __update_reloc_root(root, cow->start);
4676 level = btrfs_header_level(buf);
4677 if (btrfs_header_generation(buf) <=
4678 btrfs_root_last_snapshot(&root->root_item))
4681 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4682 rc->create_reloc_tree) {
4683 WARN_ON(!first_cow && level == 0);
4685 node = rc->backref_cache.path[level];
4686 BUG_ON(node->bytenr != buf->start &&
4687 node->new_bytenr != buf->start);
4689 drop_node_buffer(node);
4690 extent_buffer_get(cow);
4692 node->new_bytenr = cow->start;
4694 if (!node->pending) {
4695 list_move_tail(&node->list,
4696 &rc->backref_cache.pending[level]);
4701 __mark_block_processed(rc, node);
4703 if (first_cow && level > 0)
4704 rc->nodes_relocated += buf->len;
4707 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4708 ret = replace_file_extents(trans, rc, root, cow);
4713 * called before creating snapshot. it calculates metadata reservation
4714 * required for relocating tree blocks in the snapshot
4716 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4717 u64 *bytes_to_reserve)
4719 struct btrfs_root *root = pending->root;
4720 struct reloc_control *rc = root->fs_info->reloc_ctl;
4722 if (!root->reloc_root || !rc)
4725 if (!rc->merge_reloc_tree)
4728 root = root->reloc_root;
4729 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4731 * relocation is in the stage of merging trees. the space
4732 * used by merging a reloc tree is twice the size of
4733 * relocated tree nodes in the worst case. half for cowing
4734 * the reloc tree, half for cowing the fs tree. the space
4735 * used by cowing the reloc tree will be freed after the
4736 * tree is dropped. if we create snapshot, cowing the fs
4737 * tree may use more space than it frees. so we need
4738 * reserve extra space.
4740 *bytes_to_reserve += rc->nodes_relocated;
4744 * called after snapshot is created. migrate block reservation
4745 * and create reloc root for the newly created snapshot
4747 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4748 struct btrfs_pending_snapshot *pending)
4750 struct btrfs_root *root = pending->root;
4751 struct btrfs_root *reloc_root;
4752 struct btrfs_root *new_root;
4753 struct reloc_control *rc = root->fs_info->reloc_ctl;
4756 if (!root->reloc_root || !rc)
4759 rc = root->fs_info->reloc_ctl;
4760 rc->merging_rsv_size += rc->nodes_relocated;
4762 if (rc->merge_reloc_tree) {
4763 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4765 rc->nodes_relocated, true);
4770 new_root = pending->snap;
4771 reloc_root = create_reloc_root(trans, root->reloc_root,
4772 new_root->root_key.objectid);
4773 if (IS_ERR(reloc_root))
4774 return PTR_ERR(reloc_root);
4776 ret = __add_reloc_root(reloc_root);
4778 new_root->reloc_root = reloc_root;
4780 if (rc->create_reloc_tree)
4781 ret = clone_backref_node(trans, rc, root, reloc_root);