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;
1438 if (root->reloc_root) {
1439 reloc_root = root->reloc_root;
1440 reloc_root->last_trans = trans->transid;
1444 if (!rc || !rc->create_reloc_tree ||
1445 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1448 if (!trans->reloc_reserved) {
1449 rsv = trans->block_rsv;
1450 trans->block_rsv = rc->block_rsv;
1453 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1455 trans->block_rsv = rsv;
1457 ret = __add_reloc_root(reloc_root);
1459 root->reloc_root = reloc_root;
1464 * update root item of reloc tree
1466 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1467 struct btrfs_root *root)
1469 struct btrfs_fs_info *fs_info = root->fs_info;
1470 struct btrfs_root *reloc_root;
1471 struct btrfs_root_item *root_item;
1474 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1478 reloc_root = root->reloc_root;
1479 root_item = &reloc_root->root_item;
1481 /* root->reloc_root will stay until current relocation finished */
1482 if (fs_info->reloc_ctl->merge_reloc_tree &&
1483 btrfs_root_refs(root_item) == 0) {
1484 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1485 __del_reloc_root(reloc_root);
1488 if (reloc_root->commit_root != reloc_root->node) {
1489 btrfs_set_root_node(root_item, reloc_root->node);
1490 free_extent_buffer(reloc_root->commit_root);
1491 reloc_root->commit_root = btrfs_root_node(reloc_root);
1494 ret = btrfs_update_root(trans, fs_info->tree_root,
1495 &reloc_root->root_key, root_item);
1503 * helper to find first cached inode with inode number >= objectid
1506 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1508 struct rb_node *node;
1509 struct rb_node *prev;
1510 struct btrfs_inode *entry;
1511 struct inode *inode;
1513 spin_lock(&root->inode_lock);
1515 node = root->inode_tree.rb_node;
1519 entry = rb_entry(node, struct btrfs_inode, rb_node);
1521 if (objectid < btrfs_ino(entry))
1522 node = node->rb_left;
1523 else if (objectid > btrfs_ino(entry))
1524 node = node->rb_right;
1530 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1531 if (objectid <= btrfs_ino(entry)) {
1535 prev = rb_next(prev);
1539 entry = rb_entry(node, struct btrfs_inode, rb_node);
1540 inode = igrab(&entry->vfs_inode);
1542 spin_unlock(&root->inode_lock);
1546 objectid = btrfs_ino(entry) + 1;
1547 if (cond_resched_lock(&root->inode_lock))
1550 node = rb_next(node);
1552 spin_unlock(&root->inode_lock);
1556 static int in_block_group(u64 bytenr,
1557 struct btrfs_block_group_cache *block_group)
1559 if (bytenr >= block_group->key.objectid &&
1560 bytenr < block_group->key.objectid + block_group->key.offset)
1566 * get new location of data
1568 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1569 u64 bytenr, u64 num_bytes)
1571 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1572 struct btrfs_path *path;
1573 struct btrfs_file_extent_item *fi;
1574 struct extent_buffer *leaf;
1577 path = btrfs_alloc_path();
1581 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1582 ret = btrfs_lookup_file_extent(NULL, root, path,
1583 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1591 leaf = path->nodes[0];
1592 fi = btrfs_item_ptr(leaf, path->slots[0],
1593 struct btrfs_file_extent_item);
1595 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1596 btrfs_file_extent_compression(leaf, fi) ||
1597 btrfs_file_extent_encryption(leaf, fi) ||
1598 btrfs_file_extent_other_encoding(leaf, fi));
1600 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1605 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1608 btrfs_free_path(path);
1613 * update file extent items in the tree leaf to point to
1614 * the new locations.
1616 static noinline_for_stack
1617 int replace_file_extents(struct btrfs_trans_handle *trans,
1618 struct reloc_control *rc,
1619 struct btrfs_root *root,
1620 struct extent_buffer *leaf)
1622 struct btrfs_fs_info *fs_info = root->fs_info;
1623 struct btrfs_key key;
1624 struct btrfs_file_extent_item *fi;
1625 struct inode *inode = NULL;
1637 if (rc->stage != UPDATE_DATA_PTRS)
1640 /* reloc trees always use full backref */
1641 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1642 parent = leaf->start;
1646 nritems = btrfs_header_nritems(leaf);
1647 for (i = 0; i < nritems; i++) {
1648 struct btrfs_ref ref = { 0 };
1651 btrfs_item_key_to_cpu(leaf, &key, i);
1652 if (key.type != BTRFS_EXTENT_DATA_KEY)
1654 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1655 if (btrfs_file_extent_type(leaf, fi) ==
1656 BTRFS_FILE_EXTENT_INLINE)
1658 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1659 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1662 if (!in_block_group(bytenr, rc->block_group))
1666 * if we are modifying block in fs tree, wait for readpage
1667 * to complete and drop the extent cache
1669 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1671 inode = find_next_inode(root, key.objectid);
1673 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1674 btrfs_add_delayed_iput(inode);
1675 inode = find_next_inode(root, key.objectid);
1677 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1679 btrfs_file_extent_num_bytes(leaf, fi);
1680 WARN_ON(!IS_ALIGNED(key.offset,
1681 fs_info->sectorsize));
1682 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1684 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1689 btrfs_drop_extent_cache(BTRFS_I(inode),
1690 key.offset, end, 1);
1691 unlock_extent(&BTRFS_I(inode)->io_tree,
1696 ret = get_new_location(rc->data_inode, &new_bytenr,
1700 * Don't have to abort since we've not changed anything
1701 * in the file extent yet.
1706 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1709 key.offset -= btrfs_file_extent_offset(leaf, fi);
1710 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1712 ref.real_root = root->root_key.objectid;
1713 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1714 key.objectid, key.offset);
1715 ret = btrfs_inc_extent_ref(trans, &ref);
1717 btrfs_abort_transaction(trans, ret);
1721 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1723 ref.real_root = root->root_key.objectid;
1724 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1725 key.objectid, key.offset);
1726 ret = btrfs_free_extent(trans, &ref);
1728 btrfs_abort_transaction(trans, ret);
1733 btrfs_mark_buffer_dirty(leaf);
1735 btrfs_add_delayed_iput(inode);
1739 static noinline_for_stack
1740 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1741 struct btrfs_path *path, int level)
1743 struct btrfs_disk_key key1;
1744 struct btrfs_disk_key key2;
1745 btrfs_node_key(eb, &key1, slot);
1746 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1747 return memcmp(&key1, &key2, sizeof(key1));
1751 * try to replace tree blocks in fs tree with the new blocks
1752 * in reloc tree. tree blocks haven't been modified since the
1753 * reloc tree was create can be replaced.
1755 * if a block was replaced, level of the block + 1 is returned.
1756 * if no block got replaced, 0 is returned. if there are other
1757 * errors, a negative error number is returned.
1759 static noinline_for_stack
1760 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1761 struct btrfs_root *dest, struct btrfs_root *src,
1762 struct btrfs_path *path, struct btrfs_key *next_key,
1763 int lowest_level, int max_level)
1765 struct btrfs_fs_info *fs_info = dest->fs_info;
1766 struct extent_buffer *eb;
1767 struct extent_buffer *parent;
1768 struct btrfs_ref ref = { 0 };
1769 struct btrfs_key key;
1781 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1782 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1784 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1786 slot = path->slots[lowest_level];
1787 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1789 eb = btrfs_lock_root_node(dest);
1790 btrfs_set_lock_blocking_write(eb);
1791 level = btrfs_header_level(eb);
1793 if (level < lowest_level) {
1794 btrfs_tree_unlock(eb);
1795 free_extent_buffer(eb);
1800 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1803 btrfs_set_lock_blocking_write(eb);
1806 next_key->objectid = (u64)-1;
1807 next_key->type = (u8)-1;
1808 next_key->offset = (u64)-1;
1813 struct btrfs_key first_key;
1815 level = btrfs_header_level(parent);
1816 BUG_ON(level < lowest_level);
1818 ret = btrfs_bin_search(parent, &key, level, &slot);
1821 if (ret && slot > 0)
1824 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1825 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1827 old_bytenr = btrfs_node_blockptr(parent, slot);
1828 blocksize = fs_info->nodesize;
1829 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1830 btrfs_node_key_to_cpu(parent, &first_key, slot);
1832 if (level <= max_level) {
1833 eb = path->nodes[level];
1834 new_bytenr = btrfs_node_blockptr(eb,
1835 path->slots[level]);
1836 new_ptr_gen = btrfs_node_ptr_generation(eb,
1837 path->slots[level]);
1843 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1848 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1849 memcmp_node_keys(parent, slot, path, level)) {
1850 if (level <= lowest_level) {
1855 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1856 level - 1, &first_key);
1860 } else if (!extent_buffer_uptodate(eb)) {
1862 free_extent_buffer(eb);
1865 btrfs_tree_lock(eb);
1867 ret = btrfs_cow_block(trans, dest, eb, parent,
1871 btrfs_set_lock_blocking_write(eb);
1873 btrfs_tree_unlock(parent);
1874 free_extent_buffer(parent);
1881 btrfs_tree_unlock(parent);
1882 free_extent_buffer(parent);
1887 btrfs_node_key_to_cpu(path->nodes[level], &key,
1888 path->slots[level]);
1889 btrfs_release_path(path);
1891 path->lowest_level = level;
1892 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1893 path->lowest_level = 0;
1897 * Info qgroup to trace both subtrees.
1899 * We must trace both trees.
1900 * 1) Tree reloc subtree
1901 * If not traced, we will leak data numbers
1903 * If not traced, we will double count old data
1905 * We don't scan the subtree right now, but only record
1906 * the swapped tree blocks.
1907 * The real subtree rescan is delayed until we have new
1908 * CoW on the subtree root node before transaction commit.
1910 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1911 rc->block_group, parent, slot,
1912 path->nodes[level], path->slots[level],
1917 * swap blocks in fs tree and reloc tree.
1919 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1920 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1921 btrfs_mark_buffer_dirty(parent);
1923 btrfs_set_node_blockptr(path->nodes[level],
1924 path->slots[level], old_bytenr);
1925 btrfs_set_node_ptr_generation(path->nodes[level],
1926 path->slots[level], old_ptr_gen);
1927 btrfs_mark_buffer_dirty(path->nodes[level]);
1929 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1930 blocksize, path->nodes[level]->start);
1931 ref.skip_qgroup = true;
1932 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1933 ret = btrfs_inc_extent_ref(trans, &ref);
1935 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1937 ref.skip_qgroup = true;
1938 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1939 ret = btrfs_inc_extent_ref(trans, &ref);
1942 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1943 blocksize, path->nodes[level]->start);
1944 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1945 ref.skip_qgroup = true;
1946 ret = btrfs_free_extent(trans, &ref);
1949 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1951 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1952 ref.skip_qgroup = true;
1953 ret = btrfs_free_extent(trans, &ref);
1956 btrfs_unlock_up_safe(path, 0);
1961 btrfs_tree_unlock(parent);
1962 free_extent_buffer(parent);
1967 * helper to find next relocated block in reloc tree
1969 static noinline_for_stack
1970 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1973 struct extent_buffer *eb;
1978 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1980 for (i = 0; i < *level; i++) {
1981 free_extent_buffer(path->nodes[i]);
1982 path->nodes[i] = NULL;
1985 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1986 eb = path->nodes[i];
1987 nritems = btrfs_header_nritems(eb);
1988 while (path->slots[i] + 1 < nritems) {
1990 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1997 free_extent_buffer(path->nodes[i]);
1998 path->nodes[i] = NULL;
2004 * walk down reloc tree to find relocated block of lowest level
2006 static noinline_for_stack
2007 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2010 struct btrfs_fs_info *fs_info = root->fs_info;
2011 struct extent_buffer *eb = NULL;
2018 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2020 for (i = *level; i > 0; i--) {
2021 struct btrfs_key first_key;
2023 eb = path->nodes[i];
2024 nritems = btrfs_header_nritems(eb);
2025 while (path->slots[i] < nritems) {
2026 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2027 if (ptr_gen > last_snapshot)
2031 if (path->slots[i] >= nritems) {
2042 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2043 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2044 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2048 } else if (!extent_buffer_uptodate(eb)) {
2049 free_extent_buffer(eb);
2052 BUG_ON(btrfs_header_level(eb) != i - 1);
2053 path->nodes[i - 1] = eb;
2054 path->slots[i - 1] = 0;
2060 * invalidate extent cache for file extents whose key in range of
2061 * [min_key, max_key)
2063 static int invalidate_extent_cache(struct btrfs_root *root,
2064 struct btrfs_key *min_key,
2065 struct btrfs_key *max_key)
2067 struct btrfs_fs_info *fs_info = root->fs_info;
2068 struct inode *inode = NULL;
2073 objectid = min_key->objectid;
2078 if (objectid > max_key->objectid)
2081 inode = find_next_inode(root, objectid);
2084 ino = btrfs_ino(BTRFS_I(inode));
2086 if (ino > max_key->objectid) {
2092 if (!S_ISREG(inode->i_mode))
2095 if (unlikely(min_key->objectid == ino)) {
2096 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2098 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2101 start = min_key->offset;
2102 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2108 if (unlikely(max_key->objectid == ino)) {
2109 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2111 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2114 if (max_key->offset == 0)
2116 end = max_key->offset;
2117 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2124 /* the lock_extent waits for readpage to complete */
2125 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2126 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2127 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2132 static int find_next_key(struct btrfs_path *path, int level,
2133 struct btrfs_key *key)
2136 while (level < BTRFS_MAX_LEVEL) {
2137 if (!path->nodes[level])
2139 if (path->slots[level] + 1 <
2140 btrfs_header_nritems(path->nodes[level])) {
2141 btrfs_node_key_to_cpu(path->nodes[level], key,
2142 path->slots[level] + 1);
2151 * Insert current subvolume into reloc_control::dirty_subvol_roots
2153 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2154 struct reloc_control *rc,
2155 struct btrfs_root *root)
2157 struct btrfs_root *reloc_root = root->reloc_root;
2158 struct btrfs_root_item *reloc_root_item;
2160 /* @root must be a subvolume tree root with a valid reloc tree */
2161 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2164 reloc_root_item = &reloc_root->root_item;
2165 memset(&reloc_root_item->drop_progress, 0,
2166 sizeof(reloc_root_item->drop_progress));
2167 reloc_root_item->drop_level = 0;
2168 btrfs_set_root_refs(reloc_root_item, 0);
2169 btrfs_update_reloc_root(trans, root);
2171 if (list_empty(&root->reloc_dirty_list)) {
2172 btrfs_grab_fs_root(root);
2173 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2177 static int clean_dirty_subvols(struct reloc_control *rc)
2179 struct btrfs_root *root;
2180 struct btrfs_root *next;
2184 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2186 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2187 /* Merged subvolume, cleanup its reloc root */
2188 struct btrfs_root *reloc_root = root->reloc_root;
2190 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2191 list_del_init(&root->reloc_dirty_list);
2192 root->reloc_root = NULL;
2195 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2196 if (ret2 < 0 && !ret)
2199 btrfs_put_fs_root(root);
2201 /* Orphan reloc tree, just clean it up */
2202 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2203 if (ret2 < 0 && !ret)
2211 * merge the relocated tree blocks in reloc tree with corresponding
2214 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2215 struct btrfs_root *root)
2217 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2218 struct btrfs_key key;
2219 struct btrfs_key next_key;
2220 struct btrfs_trans_handle *trans = NULL;
2221 struct btrfs_root *reloc_root;
2222 struct btrfs_root_item *root_item;
2223 struct btrfs_path *path;
2224 struct extent_buffer *leaf;
2232 path = btrfs_alloc_path();
2235 path->reada = READA_FORWARD;
2237 reloc_root = root->reloc_root;
2238 root_item = &reloc_root->root_item;
2240 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2241 level = btrfs_root_level(root_item);
2242 extent_buffer_get(reloc_root->node);
2243 path->nodes[level] = reloc_root->node;
2244 path->slots[level] = 0;
2246 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2248 level = root_item->drop_level;
2250 path->lowest_level = level;
2251 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2252 path->lowest_level = 0;
2254 btrfs_free_path(path);
2258 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2259 path->slots[level]);
2260 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2262 btrfs_unlock_up_safe(path, 0);
2265 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2266 memset(&next_key, 0, sizeof(next_key));
2269 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2270 BTRFS_RESERVE_FLUSH_ALL);
2275 trans = btrfs_start_transaction(root, 0);
2276 if (IS_ERR(trans)) {
2277 err = PTR_ERR(trans);
2281 trans->block_rsv = rc->block_rsv;
2286 ret = walk_down_reloc_tree(reloc_root, path, &level);
2294 if (!find_next_key(path, level, &key) &&
2295 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2298 ret = replace_path(trans, rc, root, reloc_root, path,
2299 &next_key, level, max_level);
2308 btrfs_node_key_to_cpu(path->nodes[level], &key,
2309 path->slots[level]);
2313 ret = walk_up_reloc_tree(reloc_root, path, &level);
2319 * save the merging progress in the drop_progress.
2320 * this is OK since root refs == 1 in this case.
2322 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2323 path->slots[level]);
2324 root_item->drop_level = level;
2326 btrfs_end_transaction_throttle(trans);
2329 btrfs_btree_balance_dirty(fs_info);
2331 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2332 invalidate_extent_cache(root, &key, &next_key);
2336 * handle the case only one block in the fs tree need to be
2337 * relocated and the block is tree root.
2339 leaf = btrfs_lock_root_node(root);
2340 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2341 btrfs_tree_unlock(leaf);
2342 free_extent_buffer(leaf);
2346 btrfs_free_path(path);
2349 insert_dirty_subvol(trans, rc, root);
2352 btrfs_end_transaction_throttle(trans);
2354 btrfs_btree_balance_dirty(fs_info);
2356 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2357 invalidate_extent_cache(root, &key, &next_key);
2362 static noinline_for_stack
2363 int prepare_to_merge(struct reloc_control *rc, int err)
2365 struct btrfs_root *root = rc->extent_root;
2366 struct btrfs_fs_info *fs_info = root->fs_info;
2367 struct btrfs_root *reloc_root;
2368 struct btrfs_trans_handle *trans;
2369 LIST_HEAD(reloc_roots);
2373 mutex_lock(&fs_info->reloc_mutex);
2374 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2375 rc->merging_rsv_size += rc->nodes_relocated * 2;
2376 mutex_unlock(&fs_info->reloc_mutex);
2380 num_bytes = rc->merging_rsv_size;
2381 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2382 BTRFS_RESERVE_FLUSH_ALL);
2387 trans = btrfs_join_transaction(rc->extent_root);
2388 if (IS_ERR(trans)) {
2390 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2392 return PTR_ERR(trans);
2396 if (num_bytes != rc->merging_rsv_size) {
2397 btrfs_end_transaction(trans);
2398 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2404 rc->merge_reloc_tree = 1;
2406 while (!list_empty(&rc->reloc_roots)) {
2407 reloc_root = list_entry(rc->reloc_roots.next,
2408 struct btrfs_root, root_list);
2409 list_del_init(&reloc_root->root_list);
2411 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2412 BUG_ON(IS_ERR(root));
2413 BUG_ON(root->reloc_root != reloc_root);
2416 * set reference count to 1, so btrfs_recover_relocation
2417 * knows it should resumes merging
2420 btrfs_set_root_refs(&reloc_root->root_item, 1);
2421 btrfs_update_reloc_root(trans, root);
2423 list_add(&reloc_root->root_list, &reloc_roots);
2426 list_splice(&reloc_roots, &rc->reloc_roots);
2429 btrfs_commit_transaction(trans);
2431 btrfs_end_transaction(trans);
2435 static noinline_for_stack
2436 void free_reloc_roots(struct list_head *list)
2438 struct btrfs_root *reloc_root;
2440 while (!list_empty(list)) {
2441 reloc_root = list_entry(list->next, struct btrfs_root,
2443 __del_reloc_root(reloc_root);
2444 free_extent_buffer(reloc_root->node);
2445 free_extent_buffer(reloc_root->commit_root);
2446 reloc_root->node = NULL;
2447 reloc_root->commit_root = NULL;
2451 static noinline_for_stack
2452 void merge_reloc_roots(struct reloc_control *rc)
2454 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2455 struct btrfs_root *root;
2456 struct btrfs_root *reloc_root;
2457 LIST_HEAD(reloc_roots);
2461 root = rc->extent_root;
2464 * this serializes us with btrfs_record_root_in_transaction,
2465 * we have to make sure nobody is in the middle of
2466 * adding their roots to the list while we are
2469 mutex_lock(&fs_info->reloc_mutex);
2470 list_splice_init(&rc->reloc_roots, &reloc_roots);
2471 mutex_unlock(&fs_info->reloc_mutex);
2473 while (!list_empty(&reloc_roots)) {
2475 reloc_root = list_entry(reloc_roots.next,
2476 struct btrfs_root, root_list);
2478 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2479 root = read_fs_root(fs_info,
2480 reloc_root->root_key.offset);
2481 BUG_ON(IS_ERR(root));
2482 BUG_ON(root->reloc_root != reloc_root);
2484 ret = merge_reloc_root(rc, root);
2486 if (list_empty(&reloc_root->root_list))
2487 list_add_tail(&reloc_root->root_list,
2492 list_del_init(&reloc_root->root_list);
2493 /* Don't forget to queue this reloc root for cleanup */
2494 list_add_tail(&reloc_root->reloc_dirty_list,
2495 &rc->dirty_subvol_roots);
2505 btrfs_handle_fs_error(fs_info, ret, NULL);
2506 if (!list_empty(&reloc_roots))
2507 free_reloc_roots(&reloc_roots);
2509 /* new reloc root may be added */
2510 mutex_lock(&fs_info->reloc_mutex);
2511 list_splice_init(&rc->reloc_roots, &reloc_roots);
2512 mutex_unlock(&fs_info->reloc_mutex);
2513 if (!list_empty(&reloc_roots))
2514 free_reloc_roots(&reloc_roots);
2517 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2520 static void free_block_list(struct rb_root *blocks)
2522 struct tree_block *block;
2523 struct rb_node *rb_node;
2524 while ((rb_node = rb_first(blocks))) {
2525 block = rb_entry(rb_node, struct tree_block, rb_node);
2526 rb_erase(rb_node, blocks);
2531 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2532 struct btrfs_root *reloc_root)
2534 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2535 struct btrfs_root *root;
2537 if (reloc_root->last_trans == trans->transid)
2540 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2541 BUG_ON(IS_ERR(root));
2542 BUG_ON(root->reloc_root != reloc_root);
2544 return btrfs_record_root_in_trans(trans, root);
2547 static noinline_for_stack
2548 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2549 struct reloc_control *rc,
2550 struct backref_node *node,
2551 struct backref_edge *edges[])
2553 struct backref_node *next;
2554 struct btrfs_root *root;
2560 next = walk_up_backref(next, edges, &index);
2563 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2565 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2566 record_reloc_root_in_trans(trans, root);
2570 btrfs_record_root_in_trans(trans, root);
2571 root = root->reloc_root;
2573 if (next->new_bytenr != root->node->start) {
2574 BUG_ON(next->new_bytenr);
2575 BUG_ON(!list_empty(&next->list));
2576 next->new_bytenr = root->node->start;
2578 list_add_tail(&next->list,
2579 &rc->backref_cache.changed);
2580 __mark_block_processed(rc, next);
2586 next = walk_down_backref(edges, &index);
2587 if (!next || next->level <= node->level)
2594 /* setup backref node path for btrfs_reloc_cow_block */
2596 rc->backref_cache.path[next->level] = next;
2599 next = edges[index]->node[UPPER];
2605 * select a tree root for relocation. return NULL if the block
2606 * is reference counted. we should use do_relocation() in this
2607 * case. return a tree root pointer if the block isn't reference
2608 * counted. return -ENOENT if the block is root of reloc tree.
2610 static noinline_for_stack
2611 struct btrfs_root *select_one_root(struct backref_node *node)
2613 struct backref_node *next;
2614 struct btrfs_root *root;
2615 struct btrfs_root *fs_root = NULL;
2616 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2622 next = walk_up_backref(next, edges, &index);
2626 /* no other choice for non-references counted tree */
2627 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2630 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2636 next = walk_down_backref(edges, &index);
2637 if (!next || next->level <= node->level)
2642 return ERR_PTR(-ENOENT);
2646 static noinline_for_stack
2647 u64 calcu_metadata_size(struct reloc_control *rc,
2648 struct backref_node *node, int reserve)
2650 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2651 struct backref_node *next = node;
2652 struct backref_edge *edge;
2653 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2657 BUG_ON(reserve && node->processed);
2662 if (next->processed && (reserve || next != node))
2665 num_bytes += fs_info->nodesize;
2667 if (list_empty(&next->upper))
2670 edge = list_entry(next->upper.next,
2671 struct backref_edge, list[LOWER]);
2672 edges[index++] = edge;
2673 next = edge->node[UPPER];
2675 next = walk_down_backref(edges, &index);
2680 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2681 struct reloc_control *rc,
2682 struct backref_node *node)
2684 struct btrfs_root *root = rc->extent_root;
2685 struct btrfs_fs_info *fs_info = root->fs_info;
2690 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2692 trans->block_rsv = rc->block_rsv;
2693 rc->reserved_bytes += num_bytes;
2696 * We are under a transaction here so we can only do limited flushing.
2697 * If we get an enospc just kick back -EAGAIN so we know to drop the
2698 * transaction and try to refill when we can flush all the things.
2700 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2701 BTRFS_RESERVE_FLUSH_LIMIT);
2703 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2704 while (tmp <= rc->reserved_bytes)
2707 * only one thread can access block_rsv at this point,
2708 * so we don't need hold lock to protect block_rsv.
2709 * we expand more reservation size here to allow enough
2710 * space for relocation and we will return earlier in
2713 rc->block_rsv->size = tmp + fs_info->nodesize *
2714 RELOCATION_RESERVED_NODES;
2722 * relocate a block tree, and then update pointers in upper level
2723 * blocks that reference the block to point to the new location.
2725 * if called by link_to_upper, the block has already been relocated.
2726 * in that case this function just updates pointers.
2728 static int do_relocation(struct btrfs_trans_handle *trans,
2729 struct reloc_control *rc,
2730 struct backref_node *node,
2731 struct btrfs_key *key,
2732 struct btrfs_path *path, int lowest)
2734 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2735 struct backref_node *upper;
2736 struct backref_edge *edge;
2737 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2738 struct btrfs_root *root;
2739 struct extent_buffer *eb;
2747 BUG_ON(lowest && node->eb);
2749 path->lowest_level = node->level + 1;
2750 rc->backref_cache.path[node->level] = node;
2751 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2752 struct btrfs_key first_key;
2753 struct btrfs_ref ref = { 0 };
2757 upper = edge->node[UPPER];
2758 root = select_reloc_root(trans, rc, upper, edges);
2761 if (upper->eb && !upper->locked) {
2763 ret = btrfs_bin_search(upper->eb, key,
2764 upper->level, &slot);
2770 bytenr = btrfs_node_blockptr(upper->eb, slot);
2771 if (node->eb->start == bytenr)
2774 drop_node_buffer(upper);
2778 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2785 btrfs_release_path(path);
2790 upper->eb = path->nodes[upper->level];
2791 path->nodes[upper->level] = NULL;
2793 BUG_ON(upper->eb != path->nodes[upper->level]);
2797 path->locks[upper->level] = 0;
2799 slot = path->slots[upper->level];
2800 btrfs_release_path(path);
2802 ret = btrfs_bin_search(upper->eb, key, upper->level,
2811 bytenr = btrfs_node_blockptr(upper->eb, slot);
2813 if (bytenr != node->bytenr) {
2814 btrfs_err(root->fs_info,
2815 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2816 bytenr, node->bytenr, slot,
2822 if (node->eb->start == bytenr)
2826 blocksize = root->fs_info->nodesize;
2827 generation = btrfs_node_ptr_generation(upper->eb, slot);
2828 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2829 eb = read_tree_block(fs_info, bytenr, generation,
2830 upper->level - 1, &first_key);
2834 } else if (!extent_buffer_uptodate(eb)) {
2835 free_extent_buffer(eb);
2839 btrfs_tree_lock(eb);
2840 btrfs_set_lock_blocking_write(eb);
2843 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2845 btrfs_tree_unlock(eb);
2846 free_extent_buffer(eb);
2851 BUG_ON(node->eb != eb);
2853 btrfs_set_node_blockptr(upper->eb, slot,
2855 btrfs_set_node_ptr_generation(upper->eb, slot,
2857 btrfs_mark_buffer_dirty(upper->eb);
2859 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2860 node->eb->start, blocksize,
2862 ref.real_root = root->root_key.objectid;
2863 btrfs_init_tree_ref(&ref, node->level,
2864 btrfs_header_owner(upper->eb));
2865 ret = btrfs_inc_extent_ref(trans, &ref);
2868 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2872 if (!upper->pending)
2873 drop_node_buffer(upper);
2875 unlock_node_buffer(upper);
2880 if (!err && node->pending) {
2881 drop_node_buffer(node);
2882 list_move_tail(&node->list, &rc->backref_cache.changed);
2886 path->lowest_level = 0;
2887 BUG_ON(err == -ENOSPC);
2891 static int link_to_upper(struct btrfs_trans_handle *trans,
2892 struct reloc_control *rc,
2893 struct backref_node *node,
2894 struct btrfs_path *path)
2896 struct btrfs_key key;
2898 btrfs_node_key_to_cpu(node->eb, &key, 0);
2899 return do_relocation(trans, rc, node, &key, path, 0);
2902 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2903 struct reloc_control *rc,
2904 struct btrfs_path *path, int err)
2907 struct backref_cache *cache = &rc->backref_cache;
2908 struct backref_node *node;
2912 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2913 while (!list_empty(&cache->pending[level])) {
2914 node = list_entry(cache->pending[level].next,
2915 struct backref_node, list);
2916 list_move_tail(&node->list, &list);
2917 BUG_ON(!node->pending);
2920 ret = link_to_upper(trans, rc, node, path);
2925 list_splice_init(&list, &cache->pending[level]);
2930 static void mark_block_processed(struct reloc_control *rc,
2931 u64 bytenr, u32 blocksize)
2933 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2937 static void __mark_block_processed(struct reloc_control *rc,
2938 struct backref_node *node)
2941 if (node->level == 0 ||
2942 in_block_group(node->bytenr, rc->block_group)) {
2943 blocksize = rc->extent_root->fs_info->nodesize;
2944 mark_block_processed(rc, node->bytenr, blocksize);
2946 node->processed = 1;
2950 * mark a block and all blocks directly/indirectly reference the block
2953 static void update_processed_blocks(struct reloc_control *rc,
2954 struct backref_node *node)
2956 struct backref_node *next = node;
2957 struct backref_edge *edge;
2958 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2964 if (next->processed)
2967 __mark_block_processed(rc, next);
2969 if (list_empty(&next->upper))
2972 edge = list_entry(next->upper.next,
2973 struct backref_edge, list[LOWER]);
2974 edges[index++] = edge;
2975 next = edge->node[UPPER];
2977 next = walk_down_backref(edges, &index);
2981 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2983 u32 blocksize = rc->extent_root->fs_info->nodesize;
2985 if (test_range_bit(&rc->processed_blocks, bytenr,
2986 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2991 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2992 struct tree_block *block)
2994 struct extent_buffer *eb;
2996 BUG_ON(block->key_ready);
2997 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2998 block->level, NULL);
3001 } else if (!extent_buffer_uptodate(eb)) {
3002 free_extent_buffer(eb);
3005 if (block->level == 0)
3006 btrfs_item_key_to_cpu(eb, &block->key, 0);
3008 btrfs_node_key_to_cpu(eb, &block->key, 0);
3009 free_extent_buffer(eb);
3010 block->key_ready = 1;
3015 * helper function to relocate a tree block
3017 static int relocate_tree_block(struct btrfs_trans_handle *trans,
3018 struct reloc_control *rc,
3019 struct backref_node *node,
3020 struct btrfs_key *key,
3021 struct btrfs_path *path)
3023 struct btrfs_root *root;
3029 BUG_ON(node->processed);
3030 root = select_one_root(node);
3031 if (root == ERR_PTR(-ENOENT)) {
3032 update_processed_blocks(rc, node);
3036 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3037 ret = reserve_metadata_space(trans, rc, node);
3043 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3044 BUG_ON(node->new_bytenr);
3045 BUG_ON(!list_empty(&node->list));
3046 btrfs_record_root_in_trans(trans, root);
3047 root = root->reloc_root;
3048 node->new_bytenr = root->node->start;
3050 list_add_tail(&node->list, &rc->backref_cache.changed);
3052 path->lowest_level = node->level;
3053 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3054 btrfs_release_path(path);
3059 update_processed_blocks(rc, node);
3061 ret = do_relocation(trans, rc, node, key, path, 1);
3064 if (ret || node->level == 0 || node->cowonly)
3065 remove_backref_node(&rc->backref_cache, node);
3070 * relocate a list of blocks
3072 static noinline_for_stack
3073 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3074 struct reloc_control *rc, struct rb_root *blocks)
3076 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3077 struct backref_node *node;
3078 struct btrfs_path *path;
3079 struct tree_block *block;
3080 struct tree_block *next;
3084 path = btrfs_alloc_path();
3087 goto out_free_blocks;
3090 /* Kick in readahead for tree blocks with missing keys */
3091 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3092 if (!block->key_ready)
3093 readahead_tree_block(fs_info, block->bytenr);
3096 /* Get first keys */
3097 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3098 if (!block->key_ready) {
3099 err = get_tree_block_key(fs_info, block);
3105 /* Do tree relocation */
3106 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3107 node = build_backref_tree(rc, &block->key,
3108 block->level, block->bytenr);
3110 err = PTR_ERR(node);
3114 ret = relocate_tree_block(trans, rc, node, &block->key,
3117 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3123 err = finish_pending_nodes(trans, rc, path, err);
3126 btrfs_free_path(path);
3128 free_block_list(blocks);
3132 static noinline_for_stack
3133 int prealloc_file_extent_cluster(struct inode *inode,
3134 struct file_extent_cluster *cluster)
3139 u64 offset = BTRFS_I(inode)->index_cnt;
3143 u64 prealloc_start = cluster->start - offset;
3144 u64 prealloc_end = cluster->end - offset;
3146 struct extent_changeset *data_reserved = NULL;
3148 BUG_ON(cluster->start != cluster->boundary[0]);
3151 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3152 prealloc_end + 1 - prealloc_start);
3156 cur_offset = prealloc_start;
3157 while (nr < cluster->nr) {
3158 start = cluster->boundary[nr] - offset;
3159 if (nr + 1 < cluster->nr)
3160 end = cluster->boundary[nr + 1] - 1 - offset;
3162 end = cluster->end - offset;
3164 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3165 num_bytes = end + 1 - start;
3166 if (cur_offset < start)
3167 btrfs_free_reserved_data_space(inode, data_reserved,
3168 cur_offset, start - cur_offset);
3169 ret = btrfs_prealloc_file_range(inode, 0, start,
3170 num_bytes, num_bytes,
3171 end + 1, &alloc_hint);
3172 cur_offset = end + 1;
3173 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3178 if (cur_offset < prealloc_end)
3179 btrfs_free_reserved_data_space(inode, data_reserved,
3180 cur_offset, prealloc_end + 1 - cur_offset);
3182 inode_unlock(inode);
3183 extent_changeset_free(data_reserved);
3187 static noinline_for_stack
3188 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3191 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3192 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3193 struct extent_map *em;
3196 em = alloc_extent_map();
3201 em->len = end + 1 - start;
3202 em->block_len = em->len;
3203 em->block_start = block_start;
3204 em->bdev = fs_info->fs_devices->latest_bdev;
3205 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3207 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3209 write_lock(&em_tree->lock);
3210 ret = add_extent_mapping(em_tree, em, 0);
3211 write_unlock(&em_tree->lock);
3212 if (ret != -EEXIST) {
3213 free_extent_map(em);
3216 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3218 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3222 static int relocate_file_extent_cluster(struct inode *inode,
3223 struct file_extent_cluster *cluster)
3225 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3228 u64 offset = BTRFS_I(inode)->index_cnt;
3229 unsigned long index;
3230 unsigned long last_index;
3232 struct file_ra_state *ra;
3233 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3240 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3244 ret = prealloc_file_extent_cluster(inode, cluster);
3248 file_ra_state_init(ra, inode->i_mapping);
3250 ret = setup_extent_mapping(inode, cluster->start - offset,
3251 cluster->end - offset, cluster->start);
3255 index = (cluster->start - offset) >> PAGE_SHIFT;
3256 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3257 while (index <= last_index) {
3258 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3263 page = find_lock_page(inode->i_mapping, index);
3265 page_cache_sync_readahead(inode->i_mapping,
3267 last_index + 1 - index);
3268 page = find_or_create_page(inode->i_mapping, index,
3271 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3278 if (PageReadahead(page)) {
3279 page_cache_async_readahead(inode->i_mapping,
3280 ra, NULL, page, index,
3281 last_index + 1 - index);
3284 if (!PageUptodate(page)) {
3285 btrfs_readpage(NULL, page);
3287 if (!PageUptodate(page)) {
3290 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3292 btrfs_delalloc_release_extents(BTRFS_I(inode),
3299 page_start = page_offset(page);
3300 page_end = page_start + PAGE_SIZE - 1;
3302 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3304 set_page_extent_mapped(page);
3306 if (nr < cluster->nr &&
3307 page_start + offset == cluster->boundary[nr]) {
3308 set_extent_bits(&BTRFS_I(inode)->io_tree,
3309 page_start, page_end,
3314 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3319 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3321 btrfs_delalloc_release_extents(BTRFS_I(inode),
3324 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3325 page_start, page_end,
3326 EXTENT_LOCKED | EXTENT_BOUNDARY);
3330 set_page_dirty(page);
3332 unlock_extent(&BTRFS_I(inode)->io_tree,
3333 page_start, page_end);
3338 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3340 balance_dirty_pages_ratelimited(inode->i_mapping);
3341 btrfs_throttle(fs_info);
3343 WARN_ON(nr != cluster->nr);
3349 static noinline_for_stack
3350 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3351 struct file_extent_cluster *cluster)
3355 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3356 ret = relocate_file_extent_cluster(inode, cluster);
3363 cluster->start = extent_key->objectid;
3365 BUG_ON(cluster->nr >= MAX_EXTENTS);
3366 cluster->end = extent_key->objectid + extent_key->offset - 1;
3367 cluster->boundary[cluster->nr] = extent_key->objectid;
3370 if (cluster->nr >= MAX_EXTENTS) {
3371 ret = relocate_file_extent_cluster(inode, cluster);
3380 * helper to add a tree block to the list.
3381 * the major work is getting the generation and level of the block
3383 static int add_tree_block(struct reloc_control *rc,
3384 struct btrfs_key *extent_key,
3385 struct btrfs_path *path,
3386 struct rb_root *blocks)
3388 struct extent_buffer *eb;
3389 struct btrfs_extent_item *ei;
3390 struct btrfs_tree_block_info *bi;
3391 struct tree_block *block;
3392 struct rb_node *rb_node;
3397 eb = path->nodes[0];
3398 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3400 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3401 item_size >= sizeof(*ei) + sizeof(*bi)) {
3402 ei = btrfs_item_ptr(eb, path->slots[0],
3403 struct btrfs_extent_item);
3404 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3405 bi = (struct btrfs_tree_block_info *)(ei + 1);
3406 level = btrfs_tree_block_level(eb, bi);
3408 level = (int)extent_key->offset;
3410 generation = btrfs_extent_generation(eb, ei);
3411 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3412 btrfs_print_v0_err(eb->fs_info);
3413 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3419 btrfs_release_path(path);
3421 BUG_ON(level == -1);
3423 block = kmalloc(sizeof(*block), GFP_NOFS);
3427 block->bytenr = extent_key->objectid;
3428 block->key.objectid = rc->extent_root->fs_info->nodesize;
3429 block->key.offset = generation;
3430 block->level = level;
3431 block->key_ready = 0;
3433 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3435 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3441 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3443 static int __add_tree_block(struct reloc_control *rc,
3444 u64 bytenr, u32 blocksize,
3445 struct rb_root *blocks)
3447 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3448 struct btrfs_path *path;
3449 struct btrfs_key key;
3451 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3453 if (tree_block_processed(bytenr, rc))
3456 if (tree_search(blocks, bytenr))
3459 path = btrfs_alloc_path();
3463 key.objectid = bytenr;
3465 key.type = BTRFS_METADATA_ITEM_KEY;
3466 key.offset = (u64)-1;
3468 key.type = BTRFS_EXTENT_ITEM_KEY;
3469 key.offset = blocksize;
3472 path->search_commit_root = 1;
3473 path->skip_locking = 1;
3474 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3478 if (ret > 0 && skinny) {
3479 if (path->slots[0]) {
3481 btrfs_item_key_to_cpu(path->nodes[0], &key,
3483 if (key.objectid == bytenr &&
3484 (key.type == BTRFS_METADATA_ITEM_KEY ||
3485 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3486 key.offset == blocksize)))
3492 btrfs_release_path(path);
3498 btrfs_print_leaf(path->nodes[0]);
3500 "tree block extent item (%llu) is not found in extent tree",
3507 ret = add_tree_block(rc, &key, path, blocks);
3509 btrfs_free_path(path);
3514 * helper to check if the block use full backrefs for pointers in it
3516 static int block_use_full_backref(struct reloc_control *rc,
3517 struct extent_buffer *eb)
3522 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3523 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3526 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3527 eb->start, btrfs_header_level(eb), 1,
3531 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3538 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3539 struct btrfs_block_group_cache *block_group,
3540 struct inode *inode,
3543 struct btrfs_key key;
3544 struct btrfs_root *root = fs_info->tree_root;
3545 struct btrfs_trans_handle *trans;
3552 key.type = BTRFS_INODE_ITEM_KEY;
3555 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3560 ret = btrfs_check_trunc_cache_free_space(fs_info,
3561 &fs_info->global_block_rsv);
3565 trans = btrfs_join_transaction(root);
3566 if (IS_ERR(trans)) {
3567 ret = PTR_ERR(trans);
3571 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3573 btrfs_end_transaction(trans);
3574 btrfs_btree_balance_dirty(fs_info);
3581 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3582 * this function scans fs tree to find blocks reference the data extent
3584 static int find_data_references(struct reloc_control *rc,
3585 struct btrfs_key *extent_key,
3586 struct extent_buffer *leaf,
3587 struct btrfs_extent_data_ref *ref,
3588 struct rb_root *blocks)
3590 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3591 struct btrfs_path *path;
3592 struct tree_block *block;
3593 struct btrfs_root *root;
3594 struct btrfs_file_extent_item *fi;
3595 struct rb_node *rb_node;
3596 struct btrfs_key key;
3607 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3608 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3609 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3610 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3613 * This is an extent belonging to the free space cache, lets just delete
3614 * it and redo the search.
3616 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3617 ret = delete_block_group_cache(fs_info, rc->block_group,
3618 NULL, ref_objectid);
3624 path = btrfs_alloc_path();
3627 path->reada = READA_FORWARD;
3629 root = read_fs_root(fs_info, ref_root);
3631 err = PTR_ERR(root);
3635 key.objectid = ref_objectid;
3636 key.type = BTRFS_EXTENT_DATA_KEY;
3637 if (ref_offset > ((u64)-1 << 32))
3640 key.offset = ref_offset;
3642 path->search_commit_root = 1;
3643 path->skip_locking = 1;
3644 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3650 leaf = path->nodes[0];
3651 nritems = btrfs_header_nritems(leaf);
3653 * the references in tree blocks that use full backrefs
3654 * are not counted in
3656 if (block_use_full_backref(rc, leaf))
3660 rb_node = tree_search(blocks, leaf->start);
3665 path->slots[0] = nritems;
3668 while (ref_count > 0) {
3669 while (path->slots[0] >= nritems) {
3670 ret = btrfs_next_leaf(root, path);
3675 if (WARN_ON(ret > 0))
3678 leaf = path->nodes[0];
3679 nritems = btrfs_header_nritems(leaf);
3682 if (block_use_full_backref(rc, leaf))
3686 rb_node = tree_search(blocks, leaf->start);
3691 path->slots[0] = nritems;
3695 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3696 if (WARN_ON(key.objectid != ref_objectid ||
3697 key.type != BTRFS_EXTENT_DATA_KEY))
3700 fi = btrfs_item_ptr(leaf, path->slots[0],
3701 struct btrfs_file_extent_item);
3703 if (btrfs_file_extent_type(leaf, fi) ==
3704 BTRFS_FILE_EXTENT_INLINE)
3707 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3708 extent_key->objectid)
3711 key.offset -= btrfs_file_extent_offset(leaf, fi);
3712 if (key.offset != ref_offset)
3720 if (!tree_block_processed(leaf->start, rc)) {
3721 block = kmalloc(sizeof(*block), GFP_NOFS);
3726 block->bytenr = leaf->start;
3727 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3729 block->key_ready = 1;
3730 rb_node = tree_insert(blocks, block->bytenr,
3733 backref_tree_panic(rb_node, -EEXIST,
3739 path->slots[0] = nritems;
3745 btrfs_free_path(path);
3750 * helper to find all tree blocks that reference a given data extent
3752 static noinline_for_stack
3753 int add_data_references(struct reloc_control *rc,
3754 struct btrfs_key *extent_key,
3755 struct btrfs_path *path,
3756 struct rb_root *blocks)
3758 struct btrfs_key key;
3759 struct extent_buffer *eb;
3760 struct btrfs_extent_data_ref *dref;
3761 struct btrfs_extent_inline_ref *iref;
3764 u32 blocksize = rc->extent_root->fs_info->nodesize;
3768 eb = path->nodes[0];
3769 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3770 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3771 ptr += sizeof(struct btrfs_extent_item);
3774 iref = (struct btrfs_extent_inline_ref *)ptr;
3775 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3776 BTRFS_REF_TYPE_DATA);
3777 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3778 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3779 ret = __add_tree_block(rc, key.offset, blocksize,
3781 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3782 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3783 ret = find_data_references(rc, extent_key,
3787 btrfs_err(rc->extent_root->fs_info,
3788 "extent %llu slot %d has an invalid inline ref type",
3789 eb->start, path->slots[0]);
3795 ptr += btrfs_extent_inline_ref_size(key.type);
3801 eb = path->nodes[0];
3802 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3803 ret = btrfs_next_leaf(rc->extent_root, path);
3810 eb = path->nodes[0];
3813 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3814 if (key.objectid != extent_key->objectid)
3817 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3818 ret = __add_tree_block(rc, key.offset, blocksize,
3820 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3821 dref = btrfs_item_ptr(eb, path->slots[0],
3822 struct btrfs_extent_data_ref);
3823 ret = find_data_references(rc, extent_key,
3825 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3826 btrfs_print_v0_err(eb->fs_info);
3827 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3839 btrfs_release_path(path);
3841 free_block_list(blocks);
3846 * helper to find next unprocessed extent
3848 static noinline_for_stack
3849 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3850 struct btrfs_key *extent_key)
3852 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3853 struct btrfs_key key;
3854 struct extent_buffer *leaf;
3855 u64 start, end, last;
3858 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3861 if (rc->search_start >= last) {
3866 key.objectid = rc->search_start;
3867 key.type = BTRFS_EXTENT_ITEM_KEY;
3870 path->search_commit_root = 1;
3871 path->skip_locking = 1;
3872 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3877 leaf = path->nodes[0];
3878 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3879 ret = btrfs_next_leaf(rc->extent_root, path);
3882 leaf = path->nodes[0];
3885 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3886 if (key.objectid >= last) {
3891 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3892 key.type != BTRFS_METADATA_ITEM_KEY) {
3897 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3898 key.objectid + key.offset <= rc->search_start) {
3903 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3904 key.objectid + fs_info->nodesize <=
3910 ret = find_first_extent_bit(&rc->processed_blocks,
3911 key.objectid, &start, &end,
3912 EXTENT_DIRTY, NULL);
3914 if (ret == 0 && start <= key.objectid) {
3915 btrfs_release_path(path);
3916 rc->search_start = end + 1;
3918 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3919 rc->search_start = key.objectid + key.offset;
3921 rc->search_start = key.objectid +
3923 memcpy(extent_key, &key, sizeof(key));
3927 btrfs_release_path(path);
3931 static void set_reloc_control(struct reloc_control *rc)
3933 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3935 mutex_lock(&fs_info->reloc_mutex);
3936 fs_info->reloc_ctl = rc;
3937 mutex_unlock(&fs_info->reloc_mutex);
3940 static void unset_reloc_control(struct reloc_control *rc)
3942 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3944 mutex_lock(&fs_info->reloc_mutex);
3945 fs_info->reloc_ctl = NULL;
3946 mutex_unlock(&fs_info->reloc_mutex);
3949 static int check_extent_flags(u64 flags)
3951 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3952 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3954 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3955 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3957 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3958 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3963 static noinline_for_stack
3964 int prepare_to_relocate(struct reloc_control *rc)
3966 struct btrfs_trans_handle *trans;
3969 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3970 BTRFS_BLOCK_RSV_TEMP);
3974 memset(&rc->cluster, 0, sizeof(rc->cluster));
3975 rc->search_start = rc->block_group->key.objectid;
3976 rc->extents_found = 0;
3977 rc->nodes_relocated = 0;
3978 rc->merging_rsv_size = 0;
3979 rc->reserved_bytes = 0;
3980 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3981 RELOCATION_RESERVED_NODES;
3982 ret = btrfs_block_rsv_refill(rc->extent_root,
3983 rc->block_rsv, rc->block_rsv->size,
3984 BTRFS_RESERVE_FLUSH_ALL);
3988 rc->create_reloc_tree = 1;
3989 set_reloc_control(rc);
3991 trans = btrfs_join_transaction(rc->extent_root);
3992 if (IS_ERR(trans)) {
3993 unset_reloc_control(rc);
3995 * extent tree is not a ref_cow tree and has no reloc_root to
3996 * cleanup. And callers are responsible to free the above
3999 return PTR_ERR(trans);
4001 btrfs_commit_transaction(trans);
4005 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4007 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4008 struct rb_root blocks = RB_ROOT;
4009 struct btrfs_key key;
4010 struct btrfs_trans_handle *trans = NULL;
4011 struct btrfs_path *path;
4012 struct btrfs_extent_item *ei;
4019 path = btrfs_alloc_path();
4022 path->reada = READA_FORWARD;
4024 ret = prepare_to_relocate(rc);
4031 rc->reserved_bytes = 0;
4032 ret = btrfs_block_rsv_refill(rc->extent_root,
4033 rc->block_rsv, rc->block_rsv->size,
4034 BTRFS_RESERVE_FLUSH_ALL);
4040 trans = btrfs_start_transaction(rc->extent_root, 0);
4041 if (IS_ERR(trans)) {
4042 err = PTR_ERR(trans);
4047 if (update_backref_cache(trans, &rc->backref_cache)) {
4048 btrfs_end_transaction(trans);
4053 ret = find_next_extent(rc, path, &key);
4059 rc->extents_found++;
4061 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4062 struct btrfs_extent_item);
4063 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4064 if (item_size >= sizeof(*ei)) {
4065 flags = btrfs_extent_flags(path->nodes[0], ei);
4066 ret = check_extent_flags(flags);
4068 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4070 btrfs_print_v0_err(trans->fs_info);
4071 btrfs_abort_transaction(trans, err);
4077 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4078 ret = add_tree_block(rc, &key, path, &blocks);
4079 } else if (rc->stage == UPDATE_DATA_PTRS &&
4080 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4081 ret = add_data_references(rc, &key, path, &blocks);
4083 btrfs_release_path(path);
4091 if (!RB_EMPTY_ROOT(&blocks)) {
4092 ret = relocate_tree_blocks(trans, rc, &blocks);
4095 * if we fail to relocate tree blocks, force to update
4096 * backref cache when committing transaction.
4098 rc->backref_cache.last_trans = trans->transid - 1;
4100 if (ret != -EAGAIN) {
4104 rc->extents_found--;
4105 rc->search_start = key.objectid;
4109 btrfs_end_transaction_throttle(trans);
4110 btrfs_btree_balance_dirty(fs_info);
4113 if (rc->stage == MOVE_DATA_EXTENTS &&
4114 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4115 rc->found_file_extent = 1;
4116 ret = relocate_data_extent(rc->data_inode,
4117 &key, &rc->cluster);
4124 if (trans && progress && err == -ENOSPC) {
4125 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4133 btrfs_release_path(path);
4134 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4137 btrfs_end_transaction_throttle(trans);
4138 btrfs_btree_balance_dirty(fs_info);
4142 ret = relocate_file_extent_cluster(rc->data_inode,
4148 rc->create_reloc_tree = 0;
4149 set_reloc_control(rc);
4151 backref_cache_cleanup(&rc->backref_cache);
4152 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4154 err = prepare_to_merge(rc, err);
4156 merge_reloc_roots(rc);
4158 rc->merge_reloc_tree = 0;
4159 unset_reloc_control(rc);
4160 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4162 /* get rid of pinned extents */
4163 trans = btrfs_join_transaction(rc->extent_root);
4164 if (IS_ERR(trans)) {
4165 err = PTR_ERR(trans);
4168 btrfs_commit_transaction(trans);
4169 ret = clean_dirty_subvols(rc);
4170 if (ret < 0 && !err)
4173 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4174 btrfs_free_path(path);
4178 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4179 struct btrfs_root *root, u64 objectid)
4181 struct btrfs_path *path;
4182 struct btrfs_inode_item *item;
4183 struct extent_buffer *leaf;
4186 path = btrfs_alloc_path();
4190 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4194 leaf = path->nodes[0];
4195 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4196 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4197 btrfs_set_inode_generation(leaf, item, 1);
4198 btrfs_set_inode_size(leaf, item, 0);
4199 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4200 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4201 BTRFS_INODE_PREALLOC);
4202 btrfs_mark_buffer_dirty(leaf);
4204 btrfs_free_path(path);
4209 * helper to create inode for data relocation.
4210 * the inode is in data relocation tree and its link count is 0
4212 static noinline_for_stack
4213 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4214 struct btrfs_block_group_cache *group)
4216 struct inode *inode = NULL;
4217 struct btrfs_trans_handle *trans;
4218 struct btrfs_root *root;
4219 struct btrfs_key key;
4223 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4225 return ERR_CAST(root);
4227 trans = btrfs_start_transaction(root, 6);
4229 return ERR_CAST(trans);
4231 err = btrfs_find_free_objectid(root, &objectid);
4235 err = __insert_orphan_inode(trans, root, objectid);
4238 key.objectid = objectid;
4239 key.type = BTRFS_INODE_ITEM_KEY;
4241 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4242 BUG_ON(IS_ERR(inode));
4243 BTRFS_I(inode)->index_cnt = group->key.objectid;
4245 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4247 btrfs_end_transaction(trans);
4248 btrfs_btree_balance_dirty(fs_info);
4252 inode = ERR_PTR(err);
4257 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4259 struct reloc_control *rc;
4261 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4265 INIT_LIST_HEAD(&rc->reloc_roots);
4266 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4267 backref_cache_init(&rc->backref_cache);
4268 mapping_tree_init(&rc->reloc_root_tree);
4269 extent_io_tree_init(fs_info, &rc->processed_blocks,
4270 IO_TREE_RELOC_BLOCKS, NULL);
4275 * Print the block group being relocated
4277 static void describe_relocation(struct btrfs_fs_info *fs_info,
4278 struct btrfs_block_group_cache *block_group)
4280 char buf[128] = {'\0'};
4282 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4285 "relocating block group %llu flags %s",
4286 block_group->key.objectid, buf);
4290 * function to relocate all extents in a block group.
4292 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4294 struct btrfs_block_group_cache *bg;
4295 struct btrfs_root *extent_root = fs_info->extent_root;
4296 struct reloc_control *rc;
4297 struct inode *inode;
4298 struct btrfs_path *path;
4303 bg = btrfs_lookup_block_group(fs_info, group_start);
4307 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4308 btrfs_put_block_group(bg);
4312 rc = alloc_reloc_control(fs_info);
4314 btrfs_put_block_group(bg);
4318 rc->extent_root = extent_root;
4319 rc->block_group = bg;
4321 ret = btrfs_inc_block_group_ro(rc->block_group);
4328 path = btrfs_alloc_path();
4334 inode = lookup_free_space_inode(rc->block_group, path);
4335 btrfs_free_path(path);
4338 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4340 ret = PTR_ERR(inode);
4342 if (ret && ret != -ENOENT) {
4347 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4348 if (IS_ERR(rc->data_inode)) {
4349 err = PTR_ERR(rc->data_inode);
4350 rc->data_inode = NULL;
4354 describe_relocation(fs_info, rc->block_group);
4356 btrfs_wait_block_group_reservations(rc->block_group);
4357 btrfs_wait_nocow_writers(rc->block_group);
4358 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4359 rc->block_group->key.objectid,
4360 rc->block_group->key.offset);
4363 mutex_lock(&fs_info->cleaner_mutex);
4364 ret = relocate_block_group(rc);
4365 mutex_unlock(&fs_info->cleaner_mutex);
4370 * We may have gotten ENOSPC after we already dirtied some
4371 * extents. If writeout happens while we're relocating a
4372 * different block group we could end up hitting the
4373 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4374 * btrfs_reloc_cow_block. Make sure we write everything out
4375 * properly so we don't trip over this problem, and then break
4376 * out of the loop if we hit an error.
4378 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4379 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4383 invalidate_mapping_pages(rc->data_inode->i_mapping,
4385 rc->stage = UPDATE_DATA_PTRS;
4391 if (rc->extents_found == 0)
4394 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4398 WARN_ON(rc->block_group->pinned > 0);
4399 WARN_ON(rc->block_group->reserved > 0);
4400 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4403 btrfs_dec_block_group_ro(rc->block_group);
4404 iput(rc->data_inode);
4405 btrfs_put_block_group(rc->block_group);
4410 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4412 struct btrfs_fs_info *fs_info = root->fs_info;
4413 struct btrfs_trans_handle *trans;
4416 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4418 return PTR_ERR(trans);
4420 memset(&root->root_item.drop_progress, 0,
4421 sizeof(root->root_item.drop_progress));
4422 root->root_item.drop_level = 0;
4423 btrfs_set_root_refs(&root->root_item, 0);
4424 ret = btrfs_update_root(trans, fs_info->tree_root,
4425 &root->root_key, &root->root_item);
4427 err = btrfs_end_transaction(trans);
4434 * recover relocation interrupted by system crash.
4436 * this function resumes merging reloc trees with corresponding fs trees.
4437 * this is important for keeping the sharing of tree blocks
4439 int btrfs_recover_relocation(struct btrfs_root *root)
4441 struct btrfs_fs_info *fs_info = root->fs_info;
4442 LIST_HEAD(reloc_roots);
4443 struct btrfs_key key;
4444 struct btrfs_root *fs_root;
4445 struct btrfs_root *reloc_root;
4446 struct btrfs_path *path;
4447 struct extent_buffer *leaf;
4448 struct reloc_control *rc = NULL;
4449 struct btrfs_trans_handle *trans;
4453 path = btrfs_alloc_path();
4456 path->reada = READA_BACK;
4458 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4459 key.type = BTRFS_ROOT_ITEM_KEY;
4460 key.offset = (u64)-1;
4463 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4470 if (path->slots[0] == 0)
4474 leaf = path->nodes[0];
4475 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4476 btrfs_release_path(path);
4478 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4479 key.type != BTRFS_ROOT_ITEM_KEY)
4482 reloc_root = btrfs_read_fs_root(root, &key);
4483 if (IS_ERR(reloc_root)) {
4484 err = PTR_ERR(reloc_root);
4488 list_add(&reloc_root->root_list, &reloc_roots);
4490 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4491 fs_root = read_fs_root(fs_info,
4492 reloc_root->root_key.offset);
4493 if (IS_ERR(fs_root)) {
4494 ret = PTR_ERR(fs_root);
4495 if (ret != -ENOENT) {
4499 ret = mark_garbage_root(reloc_root);
4507 if (key.offset == 0)
4512 btrfs_release_path(path);
4514 if (list_empty(&reloc_roots))
4517 rc = alloc_reloc_control(fs_info);
4523 rc->extent_root = fs_info->extent_root;
4525 set_reloc_control(rc);
4527 trans = btrfs_join_transaction(rc->extent_root);
4528 if (IS_ERR(trans)) {
4529 unset_reloc_control(rc);
4530 err = PTR_ERR(trans);
4534 rc->merge_reloc_tree = 1;
4536 while (!list_empty(&reloc_roots)) {
4537 reloc_root = list_entry(reloc_roots.next,
4538 struct btrfs_root, root_list);
4539 list_del(&reloc_root->root_list);
4541 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4542 list_add_tail(&reloc_root->root_list,
4547 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4548 if (IS_ERR(fs_root)) {
4549 err = PTR_ERR(fs_root);
4553 err = __add_reloc_root(reloc_root);
4554 BUG_ON(err < 0); /* -ENOMEM or logic error */
4555 fs_root->reloc_root = reloc_root;
4558 err = btrfs_commit_transaction(trans);
4562 merge_reloc_roots(rc);
4564 unset_reloc_control(rc);
4566 trans = btrfs_join_transaction(rc->extent_root);
4567 if (IS_ERR(trans)) {
4568 err = PTR_ERR(trans);
4571 err = btrfs_commit_transaction(trans);
4573 ret = clean_dirty_subvols(rc);
4574 if (ret < 0 && !err)
4579 if (!list_empty(&reloc_roots))
4580 free_reloc_roots(&reloc_roots);
4582 btrfs_free_path(path);
4585 /* cleanup orphan inode in data relocation tree */
4586 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4587 if (IS_ERR(fs_root))
4588 err = PTR_ERR(fs_root);
4590 err = btrfs_orphan_cleanup(fs_root);
4596 * helper to add ordered checksum for data relocation.
4598 * cloning checksum properly handles the nodatasum extents.
4599 * it also saves CPU time to re-calculate the checksum.
4601 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4603 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4604 struct btrfs_ordered_sum *sums;
4605 struct btrfs_ordered_extent *ordered;
4611 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4612 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4614 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4615 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4616 disk_bytenr + len - 1, &list, 0);
4620 while (!list_empty(&list)) {
4621 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4622 list_del_init(&sums->list);
4625 * We need to offset the new_bytenr based on where the csum is.
4626 * We need to do this because we will read in entire prealloc
4627 * extents but we may have written to say the middle of the
4628 * prealloc extent, so we need to make sure the csum goes with
4629 * the right disk offset.
4631 * We can do this because the data reloc inode refers strictly
4632 * to the on disk bytes, so we don't have to worry about
4633 * disk_len vs real len like with real inodes since it's all
4636 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4637 sums->bytenr = new_bytenr;
4639 btrfs_add_ordered_sum(ordered, sums);
4642 btrfs_put_ordered_extent(ordered);
4646 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4647 struct btrfs_root *root, struct extent_buffer *buf,
4648 struct extent_buffer *cow)
4650 struct btrfs_fs_info *fs_info = root->fs_info;
4651 struct reloc_control *rc;
4652 struct backref_node *node;
4657 rc = fs_info->reloc_ctl;
4661 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4662 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4664 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4665 if (buf == root->node)
4666 __update_reloc_root(root, cow->start);
4669 level = btrfs_header_level(buf);
4670 if (btrfs_header_generation(buf) <=
4671 btrfs_root_last_snapshot(&root->root_item))
4674 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4675 rc->create_reloc_tree) {
4676 WARN_ON(!first_cow && level == 0);
4678 node = rc->backref_cache.path[level];
4679 BUG_ON(node->bytenr != buf->start &&
4680 node->new_bytenr != buf->start);
4682 drop_node_buffer(node);
4683 extent_buffer_get(cow);
4685 node->new_bytenr = cow->start;
4687 if (!node->pending) {
4688 list_move_tail(&node->list,
4689 &rc->backref_cache.pending[level]);
4694 __mark_block_processed(rc, node);
4696 if (first_cow && level > 0)
4697 rc->nodes_relocated += buf->len;
4700 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4701 ret = replace_file_extents(trans, rc, root, cow);
4706 * called before creating snapshot. it calculates metadata reservation
4707 * required for relocating tree blocks in the snapshot
4709 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4710 u64 *bytes_to_reserve)
4712 struct btrfs_root *root = pending->root;
4713 struct reloc_control *rc = root->fs_info->reloc_ctl;
4715 if (!root->reloc_root || !rc)
4718 if (!rc->merge_reloc_tree)
4721 root = root->reloc_root;
4722 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4724 * relocation is in the stage of merging trees. the space
4725 * used by merging a reloc tree is twice the size of
4726 * relocated tree nodes in the worst case. half for cowing
4727 * the reloc tree, half for cowing the fs tree. the space
4728 * used by cowing the reloc tree will be freed after the
4729 * tree is dropped. if we create snapshot, cowing the fs
4730 * tree may use more space than it frees. so we need
4731 * reserve extra space.
4733 *bytes_to_reserve += rc->nodes_relocated;
4737 * called after snapshot is created. migrate block reservation
4738 * and create reloc root for the newly created snapshot
4740 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4741 struct btrfs_pending_snapshot *pending)
4743 struct btrfs_root *root = pending->root;
4744 struct btrfs_root *reloc_root;
4745 struct btrfs_root *new_root;
4746 struct reloc_control *rc = root->fs_info->reloc_ctl;
4749 if (!root->reloc_root || !rc)
4752 rc = root->fs_info->reloc_ctl;
4753 rc->merging_rsv_size += rc->nodes_relocated;
4755 if (rc->merge_reloc_tree) {
4756 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4758 rc->nodes_relocated, true);
4763 new_root = pending->snap;
4764 reloc_root = create_reloc_root(trans, root->reloc_root,
4765 new_root->root_key.objectid);
4766 if (IS_ERR(reloc_root))
4767 return PTR_ERR(reloc_root);
4769 ret = __add_reloc_root(reloc_root);
4771 new_root->reloc_root = reloc_root;
4773 if (rc->create_reloc_tree)
4774 ret = clone_backref_node(trans, rc, root, reloc_root);