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"
26 * backref_node, mapping_node and tree_block start with this
29 struct rb_node rb_node;
34 * present a tree block in the backref cache
37 struct rb_node rb_node;
41 /* objectid of tree block owner, can be not uptodate */
43 /* link to pending, changed or detached list */
44 struct list_head list;
45 /* list of upper level blocks reference this block */
46 struct list_head upper;
47 /* list of child blocks in the cache */
48 struct list_head lower;
49 /* NULL if this node is not tree root */
50 struct btrfs_root *root;
51 /* extent buffer got by COW the block */
52 struct extent_buffer *eb;
53 /* level of tree block */
55 /* is the block in non-reference counted tree */
56 unsigned int cowonly:1;
57 /* 1 if no child node in the cache */
58 unsigned int lowest:1;
59 /* is the extent buffer locked */
60 unsigned int locked:1;
61 /* has the block been processed */
62 unsigned int processed:1;
63 /* have backrefs of this block been checked */
64 unsigned int checked:1;
66 * 1 if corresponding block has been cowed but some upper
67 * level block pointers may not point to the new location
69 unsigned int pending:1;
71 * 1 if the backref node isn't connected to any other
74 unsigned int detached:1;
78 * present a block pointer in the backref cache
81 struct list_head list[2];
82 struct backref_node *node[2];
87 #define RELOCATION_RESERVED_NODES 256
89 struct backref_cache {
90 /* red black tree of all backref nodes in the cache */
91 struct rb_root rb_root;
92 /* for passing backref nodes to btrfs_reloc_cow_block */
93 struct backref_node *path[BTRFS_MAX_LEVEL];
95 * list of blocks that have been cowed but some block
96 * pointers in upper level blocks may not reflect the
99 struct list_head pending[BTRFS_MAX_LEVEL];
100 /* list of backref nodes with no child node */
101 struct list_head leaves;
102 /* list of blocks that have been cowed in current transaction */
103 struct list_head changed;
104 /* list of detached backref node. */
105 struct list_head detached;
114 * map address of tree root to tree
116 struct mapping_node {
117 struct rb_node rb_node;
122 struct mapping_tree {
123 struct rb_root rb_root;
128 * present a tree block to process
131 struct rb_node rb_node;
133 struct btrfs_key key;
134 unsigned int level:8;
135 unsigned int key_ready:1;
138 #define MAX_EXTENTS 128
140 struct file_extent_cluster {
143 u64 boundary[MAX_EXTENTS];
147 struct reloc_control {
148 /* block group to relocate */
149 struct btrfs_block_group_cache *block_group;
151 struct btrfs_root *extent_root;
152 /* inode for moving data */
153 struct inode *data_inode;
155 struct btrfs_block_rsv *block_rsv;
157 struct backref_cache backref_cache;
159 struct file_extent_cluster cluster;
160 /* tree blocks have been processed */
161 struct extent_io_tree processed_blocks;
162 /* map start of tree root to corresponding reloc tree */
163 struct mapping_tree reloc_root_tree;
164 /* list of reloc trees */
165 struct list_head reloc_roots;
166 /* list of subvolume trees that get relocated */
167 struct list_head dirty_subvol_roots;
168 /* size of metadata reservation for merging reloc trees */
169 u64 merging_rsv_size;
170 /* size of relocated tree nodes */
172 /* reserved size for block group relocation*/
178 unsigned int stage:8;
179 unsigned int create_reloc_tree:1;
180 unsigned int merge_reloc_tree:1;
181 unsigned int found_file_extent:1;
184 /* stages of data relocation */
185 #define MOVE_DATA_EXTENTS 0
186 #define UPDATE_DATA_PTRS 1
188 static void remove_backref_node(struct backref_cache *cache,
189 struct backref_node *node);
190 static void __mark_block_processed(struct reloc_control *rc,
191 struct backref_node *node);
193 static void mapping_tree_init(struct mapping_tree *tree)
195 tree->rb_root = RB_ROOT;
196 spin_lock_init(&tree->lock);
199 static void backref_cache_init(struct backref_cache *cache)
202 cache->rb_root = RB_ROOT;
203 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
204 INIT_LIST_HEAD(&cache->pending[i]);
205 INIT_LIST_HEAD(&cache->changed);
206 INIT_LIST_HEAD(&cache->detached);
207 INIT_LIST_HEAD(&cache->leaves);
210 static void backref_cache_cleanup(struct backref_cache *cache)
212 struct backref_node *node;
215 while (!list_empty(&cache->detached)) {
216 node = list_entry(cache->detached.next,
217 struct backref_node, list);
218 remove_backref_node(cache, node);
221 while (!list_empty(&cache->leaves)) {
222 node = list_entry(cache->leaves.next,
223 struct backref_node, lower);
224 remove_backref_node(cache, node);
227 cache->last_trans = 0;
229 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
230 ASSERT(list_empty(&cache->pending[i]));
231 ASSERT(list_empty(&cache->changed));
232 ASSERT(list_empty(&cache->detached));
233 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
234 ASSERT(!cache->nr_nodes);
235 ASSERT(!cache->nr_edges);
238 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
240 struct backref_node *node;
242 node = kzalloc(sizeof(*node), GFP_NOFS);
244 INIT_LIST_HEAD(&node->list);
245 INIT_LIST_HEAD(&node->upper);
246 INIT_LIST_HEAD(&node->lower);
247 RB_CLEAR_NODE(&node->rb_node);
253 static void free_backref_node(struct backref_cache *cache,
254 struct backref_node *node)
262 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
264 struct backref_edge *edge;
266 edge = kzalloc(sizeof(*edge), GFP_NOFS);
272 static void free_backref_edge(struct backref_cache *cache,
273 struct backref_edge *edge)
281 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
282 struct rb_node *node)
284 struct rb_node **p = &root->rb_node;
285 struct rb_node *parent = NULL;
286 struct tree_entry *entry;
290 entry = rb_entry(parent, struct tree_entry, rb_node);
292 if (bytenr < entry->bytenr)
294 else if (bytenr > entry->bytenr)
300 rb_link_node(node, parent, p);
301 rb_insert_color(node, root);
305 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
307 struct rb_node *n = root->rb_node;
308 struct tree_entry *entry;
311 entry = rb_entry(n, struct tree_entry, rb_node);
313 if (bytenr < entry->bytenr)
315 else if (bytenr > entry->bytenr)
323 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
326 struct btrfs_fs_info *fs_info = NULL;
327 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
330 fs_info = bnode->root->fs_info;
331 btrfs_panic(fs_info, errno,
332 "Inconsistency in backref cache found at offset %llu",
337 * walk up backref nodes until reach node presents tree root
339 static struct backref_node *walk_up_backref(struct backref_node *node,
340 struct backref_edge *edges[],
343 struct backref_edge *edge;
346 while (!list_empty(&node->upper)) {
347 edge = list_entry(node->upper.next,
348 struct backref_edge, list[LOWER]);
350 node = edge->node[UPPER];
352 BUG_ON(node->detached);
358 * walk down backref nodes to find start of next reference path
360 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
363 struct backref_edge *edge;
364 struct backref_node *lower;
368 edge = edges[idx - 1];
369 lower = edge->node[LOWER];
370 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
374 edge = list_entry(edge->list[LOWER].next,
375 struct backref_edge, list[LOWER]);
376 edges[idx - 1] = edge;
378 return edge->node[UPPER];
384 static void unlock_node_buffer(struct backref_node *node)
387 btrfs_tree_unlock(node->eb);
392 static void drop_node_buffer(struct backref_node *node)
395 unlock_node_buffer(node);
396 free_extent_buffer(node->eb);
401 static void drop_backref_node(struct backref_cache *tree,
402 struct backref_node *node)
404 BUG_ON(!list_empty(&node->upper));
406 drop_node_buffer(node);
407 list_del(&node->list);
408 list_del(&node->lower);
409 if (!RB_EMPTY_NODE(&node->rb_node))
410 rb_erase(&node->rb_node, &tree->rb_root);
411 free_backref_node(tree, node);
415 * remove a backref node from the backref cache
417 static void remove_backref_node(struct backref_cache *cache,
418 struct backref_node *node)
420 struct backref_node *upper;
421 struct backref_edge *edge;
426 BUG_ON(!node->lowest && !node->detached);
427 while (!list_empty(&node->upper)) {
428 edge = list_entry(node->upper.next, struct backref_edge,
430 upper = edge->node[UPPER];
431 list_del(&edge->list[LOWER]);
432 list_del(&edge->list[UPPER]);
433 free_backref_edge(cache, edge);
435 if (RB_EMPTY_NODE(&upper->rb_node)) {
436 BUG_ON(!list_empty(&node->upper));
437 drop_backref_node(cache, node);
443 * add the node to leaf node list if no other
444 * child block cached.
446 if (list_empty(&upper->lower)) {
447 list_add_tail(&upper->lower, &cache->leaves);
452 drop_backref_node(cache, node);
455 static void update_backref_node(struct backref_cache *cache,
456 struct backref_node *node, u64 bytenr)
458 struct rb_node *rb_node;
459 rb_erase(&node->rb_node, &cache->rb_root);
460 node->bytenr = bytenr;
461 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
463 backref_tree_panic(rb_node, -EEXIST, bytenr);
467 * update backref cache after a transaction commit
469 static int update_backref_cache(struct btrfs_trans_handle *trans,
470 struct backref_cache *cache)
472 struct backref_node *node;
475 if (cache->last_trans == 0) {
476 cache->last_trans = trans->transid;
480 if (cache->last_trans == trans->transid)
484 * detached nodes are used to avoid unnecessary backref
485 * lookup. transaction commit changes the extent tree.
486 * so the detached nodes are no longer useful.
488 while (!list_empty(&cache->detached)) {
489 node = list_entry(cache->detached.next,
490 struct backref_node, list);
491 remove_backref_node(cache, node);
494 while (!list_empty(&cache->changed)) {
495 node = list_entry(cache->changed.next,
496 struct backref_node, list);
497 list_del_init(&node->list);
498 BUG_ON(node->pending);
499 update_backref_node(cache, node, node->new_bytenr);
503 * some nodes can be left in the pending list if there were
504 * errors during processing the pending nodes.
506 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
507 list_for_each_entry(node, &cache->pending[level], list) {
508 BUG_ON(!node->pending);
509 if (node->bytenr == node->new_bytenr)
511 update_backref_node(cache, node, node->new_bytenr);
515 cache->last_trans = 0;
520 static int should_ignore_root(struct btrfs_root *root)
522 struct btrfs_root *reloc_root;
524 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
527 reloc_root = root->reloc_root;
531 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
532 root->fs_info->running_transaction->transid - 1)
535 * if there is reloc tree and it was created in previous
536 * transaction backref lookup can find the reloc tree,
537 * so backref node for the fs tree root is useless for
543 * find reloc tree by address of tree root
545 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
548 struct rb_node *rb_node;
549 struct mapping_node *node;
550 struct btrfs_root *root = NULL;
552 spin_lock(&rc->reloc_root_tree.lock);
553 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
555 node = rb_entry(rb_node, struct mapping_node, rb_node);
556 root = (struct btrfs_root *)node->data;
558 spin_unlock(&rc->reloc_root_tree.lock);
562 static int is_cowonly_root(u64 root_objectid)
564 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
565 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
566 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
567 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
568 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
569 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
570 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
571 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
572 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
577 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
580 struct btrfs_key key;
582 key.objectid = root_objectid;
583 key.type = BTRFS_ROOT_ITEM_KEY;
584 if (is_cowonly_root(root_objectid))
587 key.offset = (u64)-1;
589 return btrfs_get_fs_root(fs_info, &key, false);
592 static noinline_for_stack
593 int find_inline_backref(struct extent_buffer *leaf, int slot,
594 unsigned long *ptr, unsigned long *end)
596 struct btrfs_key key;
597 struct btrfs_extent_item *ei;
598 struct btrfs_tree_block_info *bi;
601 btrfs_item_key_to_cpu(leaf, &key, slot);
603 item_size = btrfs_item_size_nr(leaf, slot);
604 if (item_size < sizeof(*ei)) {
605 btrfs_print_v0_err(leaf->fs_info);
606 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
609 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
610 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
611 BTRFS_EXTENT_FLAG_TREE_BLOCK));
613 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
614 item_size <= sizeof(*ei) + sizeof(*bi)) {
615 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
618 if (key.type == BTRFS_METADATA_ITEM_KEY &&
619 item_size <= sizeof(*ei)) {
620 WARN_ON(item_size < sizeof(*ei));
624 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
625 bi = (struct btrfs_tree_block_info *)(ei + 1);
626 *ptr = (unsigned long)(bi + 1);
628 *ptr = (unsigned long)(ei + 1);
630 *end = (unsigned long)ei + item_size;
635 * build backref tree for a given tree block. root of the backref tree
636 * corresponds the tree block, leaves of the backref tree correspond
637 * roots of b-trees that reference the tree block.
639 * the basic idea of this function is check backrefs of a given block
640 * to find upper level blocks that reference the block, and then check
641 * backrefs of these upper level blocks recursively. the recursion stop
642 * when tree root is reached or backrefs for the block is cached.
644 * NOTE: if we find backrefs for a block are cached, we know backrefs
645 * for all upper level blocks that directly/indirectly reference the
646 * block are also cached.
648 static noinline_for_stack
649 struct backref_node *build_backref_tree(struct reloc_control *rc,
650 struct btrfs_key *node_key,
651 int level, u64 bytenr)
653 struct backref_cache *cache = &rc->backref_cache;
654 struct btrfs_path *path1; /* For searching extent root */
655 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
656 struct extent_buffer *eb;
657 struct btrfs_root *root;
658 struct backref_node *cur;
659 struct backref_node *upper;
660 struct backref_node *lower;
661 struct backref_node *node = NULL;
662 struct backref_node *exist = NULL;
663 struct backref_edge *edge;
664 struct rb_node *rb_node;
665 struct btrfs_key key;
668 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
673 bool need_check = true;
675 path1 = btrfs_alloc_path();
676 path2 = btrfs_alloc_path();
677 if (!path1 || !path2) {
681 path1->reada = READA_FORWARD;
682 path2->reada = READA_FORWARD;
684 node = alloc_backref_node(cache);
690 node->bytenr = bytenr;
697 key.objectid = cur->bytenr;
698 key.type = BTRFS_METADATA_ITEM_KEY;
699 key.offset = (u64)-1;
701 path1->search_commit_root = 1;
702 path1->skip_locking = 1;
703 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
710 ASSERT(path1->slots[0]);
714 WARN_ON(cur->checked);
715 if (!list_empty(&cur->upper)) {
717 * the backref was added previously when processing
718 * backref of type BTRFS_TREE_BLOCK_REF_KEY
720 ASSERT(list_is_singular(&cur->upper));
721 edge = list_entry(cur->upper.next, struct backref_edge,
723 ASSERT(list_empty(&edge->list[UPPER]));
724 exist = edge->node[UPPER];
726 * add the upper level block to pending list if we need
730 list_add_tail(&edge->list[UPPER], &list);
737 eb = path1->nodes[0];
740 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
741 ret = btrfs_next_leaf(rc->extent_root, path1);
748 eb = path1->nodes[0];
751 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
752 if (key.objectid != cur->bytenr) {
757 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
758 key.type == BTRFS_METADATA_ITEM_KEY) {
759 ret = find_inline_backref(eb, path1->slots[0],
767 /* update key for inline back ref */
768 struct btrfs_extent_inline_ref *iref;
770 iref = (struct btrfs_extent_inline_ref *)ptr;
771 type = btrfs_get_extent_inline_ref_type(eb, iref,
772 BTRFS_REF_TYPE_BLOCK);
773 if (type == BTRFS_REF_TYPE_INVALID) {
778 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
780 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
781 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
785 * Parent node found and matches current inline ref, no need to
786 * rebuild this node for this inline ref.
789 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
790 exist->owner == key.offset) ||
791 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
792 exist->bytenr == key.offset))) {
797 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
798 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
799 if (key.objectid == key.offset) {
801 * Only root blocks of reloc trees use backref
802 * pointing to itself.
804 root = find_reloc_root(rc, cur->bytenr);
810 edge = alloc_backref_edge(cache);
815 rb_node = tree_search(&cache->rb_root, key.offset);
817 upper = alloc_backref_node(cache);
819 free_backref_edge(cache, edge);
823 upper->bytenr = key.offset;
824 upper->level = cur->level + 1;
826 * backrefs for the upper level block isn't
827 * cached, add the block to pending list
829 list_add_tail(&edge->list[UPPER], &list);
831 upper = rb_entry(rb_node, struct backref_node,
833 ASSERT(upper->checked);
834 INIT_LIST_HEAD(&edge->list[UPPER]);
836 list_add_tail(&edge->list[LOWER], &cur->upper);
837 edge->node[LOWER] = cur;
838 edge->node[UPPER] = upper;
841 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
843 btrfs_print_v0_err(rc->extent_root->fs_info);
844 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
847 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
852 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
853 * means the root objectid. We need to search the tree to get
856 root = read_fs_root(rc->extent_root->fs_info, key.offset);
862 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
865 if (btrfs_root_level(&root->root_item) == cur->level) {
867 ASSERT(btrfs_root_bytenr(&root->root_item) ==
869 if (should_ignore_root(root))
870 list_add(&cur->list, &useless);
876 level = cur->level + 1;
878 /* Search the tree to find parent blocks referring the block. */
879 path2->search_commit_root = 1;
880 path2->skip_locking = 1;
881 path2->lowest_level = level;
882 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
883 path2->lowest_level = 0;
888 if (ret > 0 && path2->slots[level] > 0)
889 path2->slots[level]--;
891 eb = path2->nodes[level];
892 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
894 btrfs_err(root->fs_info,
895 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
896 cur->bytenr, level - 1,
897 root->root_key.objectid,
898 node_key->objectid, node_key->type,
906 /* Add all nodes and edges in the path */
907 for (; level < BTRFS_MAX_LEVEL; level++) {
908 if (!path2->nodes[level]) {
909 ASSERT(btrfs_root_bytenr(&root->root_item) ==
911 if (should_ignore_root(root))
912 list_add(&lower->list, &useless);
918 edge = alloc_backref_edge(cache);
924 eb = path2->nodes[level];
925 rb_node = tree_search(&cache->rb_root, eb->start);
927 upper = alloc_backref_node(cache);
929 free_backref_edge(cache, edge);
933 upper->bytenr = eb->start;
934 upper->owner = btrfs_header_owner(eb);
935 upper->level = lower->level + 1;
936 if (!test_bit(BTRFS_ROOT_REF_COWS,
941 * if we know the block isn't shared
942 * we can void checking its backrefs.
944 if (btrfs_block_can_be_shared(root, eb))
950 * add the block to pending list if we
951 * need check its backrefs, we only do this once
952 * while walking up a tree as we will catch
953 * anything else later on.
955 if (!upper->checked && need_check) {
957 list_add_tail(&edge->list[UPPER],
962 INIT_LIST_HEAD(&edge->list[UPPER]);
965 upper = rb_entry(rb_node, struct backref_node,
967 ASSERT(upper->checked);
968 INIT_LIST_HEAD(&edge->list[UPPER]);
970 upper->owner = btrfs_header_owner(eb);
972 list_add_tail(&edge->list[LOWER], &lower->upper);
973 edge->node[LOWER] = lower;
974 edge->node[UPPER] = upper;
981 btrfs_release_path(path2);
984 ptr += btrfs_extent_inline_ref_size(key.type);
994 btrfs_release_path(path1);
999 /* the pending list isn't empty, take the first block to process */
1000 if (!list_empty(&list)) {
1001 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1002 list_del_init(&edge->list[UPPER]);
1003 cur = edge->node[UPPER];
1008 * everything goes well, connect backref nodes and insert backref nodes
1011 ASSERT(node->checked);
1012 cowonly = node->cowonly;
1014 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1017 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1018 list_add_tail(&node->lower, &cache->leaves);
1021 list_for_each_entry(edge, &node->upper, list[LOWER])
1022 list_add_tail(&edge->list[UPPER], &list);
1024 while (!list_empty(&list)) {
1025 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1026 list_del_init(&edge->list[UPPER]);
1027 upper = edge->node[UPPER];
1028 if (upper->detached) {
1029 list_del(&edge->list[LOWER]);
1030 lower = edge->node[LOWER];
1031 free_backref_edge(cache, edge);
1032 if (list_empty(&lower->upper))
1033 list_add(&lower->list, &useless);
1037 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1038 if (upper->lowest) {
1039 list_del_init(&upper->lower);
1043 list_add_tail(&edge->list[UPPER], &upper->lower);
1047 if (!upper->checked) {
1049 * Still want to blow up for developers since this is a
1056 if (cowonly != upper->cowonly) {
1063 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1066 backref_tree_panic(rb_node, -EEXIST,
1070 list_add_tail(&edge->list[UPPER], &upper->lower);
1072 list_for_each_entry(edge, &upper->upper, list[LOWER])
1073 list_add_tail(&edge->list[UPPER], &list);
1076 * process useless backref nodes. backref nodes for tree leaves
1077 * are deleted from the cache. backref nodes for upper level
1078 * tree blocks are left in the cache to avoid unnecessary backref
1081 while (!list_empty(&useless)) {
1082 upper = list_entry(useless.next, struct backref_node, list);
1083 list_del_init(&upper->list);
1084 ASSERT(list_empty(&upper->upper));
1087 if (upper->lowest) {
1088 list_del_init(&upper->lower);
1091 while (!list_empty(&upper->lower)) {
1092 edge = list_entry(upper->lower.next,
1093 struct backref_edge, list[UPPER]);
1094 list_del(&edge->list[UPPER]);
1095 list_del(&edge->list[LOWER]);
1096 lower = edge->node[LOWER];
1097 free_backref_edge(cache, edge);
1099 if (list_empty(&lower->upper))
1100 list_add(&lower->list, &useless);
1102 __mark_block_processed(rc, upper);
1103 if (upper->level > 0) {
1104 list_add(&upper->list, &cache->detached);
1105 upper->detached = 1;
1107 rb_erase(&upper->rb_node, &cache->rb_root);
1108 free_backref_node(cache, upper);
1112 btrfs_free_path(path1);
1113 btrfs_free_path(path2);
1115 while (!list_empty(&useless)) {
1116 lower = list_entry(useless.next,
1117 struct backref_node, list);
1118 list_del_init(&lower->list);
1120 while (!list_empty(&list)) {
1121 edge = list_first_entry(&list, struct backref_edge,
1123 list_del(&edge->list[UPPER]);
1124 list_del(&edge->list[LOWER]);
1125 lower = edge->node[LOWER];
1126 upper = edge->node[UPPER];
1127 free_backref_edge(cache, edge);
1130 * Lower is no longer linked to any upper backref nodes
1131 * and isn't in the cache, we can free it ourselves.
1133 if (list_empty(&lower->upper) &&
1134 RB_EMPTY_NODE(&lower->rb_node))
1135 list_add(&lower->list, &useless);
1137 if (!RB_EMPTY_NODE(&upper->rb_node))
1140 /* Add this guy's upper edges to the list to process */
1141 list_for_each_entry(edge, &upper->upper, list[LOWER])
1142 list_add_tail(&edge->list[UPPER], &list);
1143 if (list_empty(&upper->upper))
1144 list_add(&upper->list, &useless);
1147 while (!list_empty(&useless)) {
1148 lower = list_entry(useless.next,
1149 struct backref_node, list);
1150 list_del_init(&lower->list);
1153 free_backref_node(cache, lower);
1156 free_backref_node(cache, node);
1157 return ERR_PTR(err);
1159 ASSERT(!node || !node->detached);
1164 * helper to add backref node for the newly created snapshot.
1165 * the backref node is created by cloning backref node that
1166 * corresponds to root of source tree
1168 static int clone_backref_node(struct btrfs_trans_handle *trans,
1169 struct reloc_control *rc,
1170 struct btrfs_root *src,
1171 struct btrfs_root *dest)
1173 struct btrfs_root *reloc_root = src->reloc_root;
1174 struct backref_cache *cache = &rc->backref_cache;
1175 struct backref_node *node = NULL;
1176 struct backref_node *new_node;
1177 struct backref_edge *edge;
1178 struct backref_edge *new_edge;
1179 struct rb_node *rb_node;
1181 if (cache->last_trans > 0)
1182 update_backref_cache(trans, cache);
1184 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1186 node = rb_entry(rb_node, struct backref_node, rb_node);
1190 BUG_ON(node->new_bytenr != reloc_root->node->start);
1194 rb_node = tree_search(&cache->rb_root,
1195 reloc_root->commit_root->start);
1197 node = rb_entry(rb_node, struct backref_node,
1199 BUG_ON(node->detached);
1206 new_node = alloc_backref_node(cache);
1210 new_node->bytenr = dest->node->start;
1211 new_node->level = node->level;
1212 new_node->lowest = node->lowest;
1213 new_node->checked = 1;
1214 new_node->root = dest;
1216 if (!node->lowest) {
1217 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1218 new_edge = alloc_backref_edge(cache);
1222 new_edge->node[UPPER] = new_node;
1223 new_edge->node[LOWER] = edge->node[LOWER];
1224 list_add_tail(&new_edge->list[UPPER],
1228 list_add_tail(&new_node->lower, &cache->leaves);
1231 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1232 &new_node->rb_node);
1234 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1236 if (!new_node->lowest) {
1237 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1238 list_add_tail(&new_edge->list[LOWER],
1239 &new_edge->node[LOWER]->upper);
1244 while (!list_empty(&new_node->lower)) {
1245 new_edge = list_entry(new_node->lower.next,
1246 struct backref_edge, list[UPPER]);
1247 list_del(&new_edge->list[UPPER]);
1248 free_backref_edge(cache, new_edge);
1250 free_backref_node(cache, new_node);
1255 * helper to add 'address of tree root -> reloc tree' mapping
1257 static int __must_check __add_reloc_root(struct btrfs_root *root)
1259 struct btrfs_fs_info *fs_info = root->fs_info;
1260 struct rb_node *rb_node;
1261 struct mapping_node *node;
1262 struct reloc_control *rc = fs_info->reloc_ctl;
1264 node = kmalloc(sizeof(*node), GFP_NOFS);
1268 node->bytenr = root->node->start;
1271 spin_lock(&rc->reloc_root_tree.lock);
1272 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1273 node->bytenr, &node->rb_node);
1274 spin_unlock(&rc->reloc_root_tree.lock);
1276 btrfs_panic(fs_info, -EEXIST,
1277 "Duplicate root found for start=%llu while inserting into relocation tree",
1281 list_add_tail(&root->root_list, &rc->reloc_roots);
1286 * helper to delete the 'address of tree root -> reloc tree'
1289 static void __del_reloc_root(struct btrfs_root *root)
1291 struct btrfs_fs_info *fs_info = root->fs_info;
1292 struct rb_node *rb_node;
1293 struct mapping_node *node = NULL;
1294 struct reloc_control *rc = fs_info->reloc_ctl;
1296 if (rc && root->node) {
1297 spin_lock(&rc->reloc_root_tree.lock);
1298 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1301 node = rb_entry(rb_node, struct mapping_node, rb_node);
1302 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1304 spin_unlock(&rc->reloc_root_tree.lock);
1307 BUG_ON((struct btrfs_root *)node->data != root);
1310 spin_lock(&fs_info->trans_lock);
1311 list_del_init(&root->root_list);
1312 spin_unlock(&fs_info->trans_lock);
1317 * helper to update the 'address of tree root -> reloc tree'
1320 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1322 struct btrfs_fs_info *fs_info = root->fs_info;
1323 struct rb_node *rb_node;
1324 struct mapping_node *node = NULL;
1325 struct reloc_control *rc = fs_info->reloc_ctl;
1327 spin_lock(&rc->reloc_root_tree.lock);
1328 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1331 node = rb_entry(rb_node, struct mapping_node, rb_node);
1332 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1334 spin_unlock(&rc->reloc_root_tree.lock);
1338 BUG_ON((struct btrfs_root *)node->data != root);
1340 spin_lock(&rc->reloc_root_tree.lock);
1341 node->bytenr = new_bytenr;
1342 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1343 node->bytenr, &node->rb_node);
1344 spin_unlock(&rc->reloc_root_tree.lock);
1346 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1350 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1351 struct btrfs_root *root, u64 objectid)
1353 struct btrfs_fs_info *fs_info = root->fs_info;
1354 struct btrfs_root *reloc_root;
1355 struct extent_buffer *eb;
1356 struct btrfs_root_item *root_item;
1357 struct btrfs_key root_key;
1360 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1363 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1364 root_key.type = BTRFS_ROOT_ITEM_KEY;
1365 root_key.offset = objectid;
1367 if (root->root_key.objectid == objectid) {
1368 u64 commit_root_gen;
1370 /* called by btrfs_init_reloc_root */
1371 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1372 BTRFS_TREE_RELOC_OBJECTID);
1375 * Set the last_snapshot field to the generation of the commit
1376 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1377 * correctly (returns true) when the relocation root is created
1378 * either inside the critical section of a transaction commit
1379 * (through transaction.c:qgroup_account_snapshot()) and when
1380 * it's created before the transaction commit is started.
1382 commit_root_gen = btrfs_header_generation(root->commit_root);
1383 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1386 * called by btrfs_reloc_post_snapshot_hook.
1387 * the source tree is a reloc tree, all tree blocks
1388 * modified after it was created have RELOC flag
1389 * set in their headers. so it's OK to not update
1390 * the 'last_snapshot'.
1392 ret = btrfs_copy_root(trans, root, root->node, &eb,
1393 BTRFS_TREE_RELOC_OBJECTID);
1397 memcpy(root_item, &root->root_item, sizeof(*root_item));
1398 btrfs_set_root_bytenr(root_item, eb->start);
1399 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1400 btrfs_set_root_generation(root_item, trans->transid);
1402 if (root->root_key.objectid == objectid) {
1403 btrfs_set_root_refs(root_item, 0);
1404 memset(&root_item->drop_progress, 0,
1405 sizeof(struct btrfs_disk_key));
1406 root_item->drop_level = 0;
1409 btrfs_tree_unlock(eb);
1410 free_extent_buffer(eb);
1412 ret = btrfs_insert_root(trans, fs_info->tree_root,
1413 &root_key, root_item);
1417 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1418 BUG_ON(IS_ERR(reloc_root));
1419 reloc_root->last_trans = trans->transid;
1424 * create reloc tree for a given fs tree. reloc tree is just a
1425 * snapshot of the fs tree with special root objectid.
1427 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1428 struct btrfs_root *root)
1430 struct btrfs_fs_info *fs_info = root->fs_info;
1431 struct btrfs_root *reloc_root;
1432 struct reloc_control *rc = fs_info->reloc_ctl;
1433 struct btrfs_block_rsv *rsv;
1437 if (root->reloc_root) {
1438 reloc_root = root->reloc_root;
1439 reloc_root->last_trans = trans->transid;
1443 if (!rc || !rc->create_reloc_tree ||
1444 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1447 if (!trans->reloc_reserved) {
1448 rsv = trans->block_rsv;
1449 trans->block_rsv = rc->block_rsv;
1452 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1454 trans->block_rsv = rsv;
1456 ret = __add_reloc_root(reloc_root);
1458 root->reloc_root = reloc_root;
1463 * update root item of reloc tree
1465 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1466 struct btrfs_root *root)
1468 struct btrfs_fs_info *fs_info = root->fs_info;
1469 struct btrfs_root *reloc_root;
1470 struct btrfs_root_item *root_item;
1473 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state) ||
1477 reloc_root = root->reloc_root;
1478 root_item = &reloc_root->root_item;
1480 /* root->reloc_root will stay until current relocation finished */
1481 if (fs_info->reloc_ctl->merge_reloc_tree &&
1482 btrfs_root_refs(root_item) == 0) {
1483 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1484 __del_reloc_root(reloc_root);
1487 if (reloc_root->commit_root != reloc_root->node) {
1488 btrfs_set_root_node(root_item, reloc_root->node);
1489 free_extent_buffer(reloc_root->commit_root);
1490 reloc_root->commit_root = btrfs_root_node(reloc_root);
1493 ret = btrfs_update_root(trans, fs_info->tree_root,
1494 &reloc_root->root_key, root_item);
1502 * helper to find first cached inode with inode number >= objectid
1505 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1507 struct rb_node *node;
1508 struct rb_node *prev;
1509 struct btrfs_inode *entry;
1510 struct inode *inode;
1512 spin_lock(&root->inode_lock);
1514 node = root->inode_tree.rb_node;
1518 entry = rb_entry(node, struct btrfs_inode, rb_node);
1520 if (objectid < btrfs_ino(entry))
1521 node = node->rb_left;
1522 else if (objectid > btrfs_ino(entry))
1523 node = node->rb_right;
1529 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1530 if (objectid <= btrfs_ino(entry)) {
1534 prev = rb_next(prev);
1538 entry = rb_entry(node, struct btrfs_inode, rb_node);
1539 inode = igrab(&entry->vfs_inode);
1541 spin_unlock(&root->inode_lock);
1545 objectid = btrfs_ino(entry) + 1;
1546 if (cond_resched_lock(&root->inode_lock))
1549 node = rb_next(node);
1551 spin_unlock(&root->inode_lock);
1555 static int in_block_group(u64 bytenr,
1556 struct btrfs_block_group_cache *block_group)
1558 if (bytenr >= block_group->key.objectid &&
1559 bytenr < block_group->key.objectid + block_group->key.offset)
1565 * get new location of data
1567 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1568 u64 bytenr, u64 num_bytes)
1570 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1571 struct btrfs_path *path;
1572 struct btrfs_file_extent_item *fi;
1573 struct extent_buffer *leaf;
1576 path = btrfs_alloc_path();
1580 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1581 ret = btrfs_lookup_file_extent(NULL, root, path,
1582 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1590 leaf = path->nodes[0];
1591 fi = btrfs_item_ptr(leaf, path->slots[0],
1592 struct btrfs_file_extent_item);
1594 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1595 btrfs_file_extent_compression(leaf, fi) ||
1596 btrfs_file_extent_encryption(leaf, fi) ||
1597 btrfs_file_extent_other_encoding(leaf, fi));
1599 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1604 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1607 btrfs_free_path(path);
1612 * update file extent items in the tree leaf to point to
1613 * the new locations.
1615 static noinline_for_stack
1616 int replace_file_extents(struct btrfs_trans_handle *trans,
1617 struct reloc_control *rc,
1618 struct btrfs_root *root,
1619 struct extent_buffer *leaf)
1621 struct btrfs_fs_info *fs_info = root->fs_info;
1622 struct btrfs_key key;
1623 struct btrfs_file_extent_item *fi;
1624 struct inode *inode = NULL;
1636 if (rc->stage != UPDATE_DATA_PTRS)
1639 /* reloc trees always use full backref */
1640 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1641 parent = leaf->start;
1645 nritems = btrfs_header_nritems(leaf);
1646 for (i = 0; i < nritems; i++) {
1647 struct btrfs_ref ref = { 0 };
1650 btrfs_item_key_to_cpu(leaf, &key, i);
1651 if (key.type != BTRFS_EXTENT_DATA_KEY)
1653 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1654 if (btrfs_file_extent_type(leaf, fi) ==
1655 BTRFS_FILE_EXTENT_INLINE)
1657 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1658 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1661 if (!in_block_group(bytenr, rc->block_group))
1665 * if we are modifying block in fs tree, wait for readpage
1666 * to complete and drop the extent cache
1668 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1670 inode = find_next_inode(root, key.objectid);
1672 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1673 btrfs_add_delayed_iput(inode);
1674 inode = find_next_inode(root, key.objectid);
1676 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1678 btrfs_file_extent_num_bytes(leaf, fi);
1679 WARN_ON(!IS_ALIGNED(key.offset,
1680 fs_info->sectorsize));
1681 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1683 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1688 btrfs_drop_extent_cache(BTRFS_I(inode),
1689 key.offset, end, 1);
1690 unlock_extent(&BTRFS_I(inode)->io_tree,
1695 ret = get_new_location(rc->data_inode, &new_bytenr,
1699 * Don't have to abort since we've not changed anything
1700 * in the file extent yet.
1705 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1708 key.offset -= btrfs_file_extent_offset(leaf, fi);
1709 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1711 ref.real_root = root->root_key.objectid;
1712 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1713 key.objectid, key.offset);
1714 ret = btrfs_inc_extent_ref(trans, &ref);
1716 btrfs_abort_transaction(trans, ret);
1720 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1722 ref.real_root = root->root_key.objectid;
1723 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1724 key.objectid, key.offset);
1725 ret = btrfs_free_extent(trans, &ref);
1727 btrfs_abort_transaction(trans, ret);
1732 btrfs_mark_buffer_dirty(leaf);
1734 btrfs_add_delayed_iput(inode);
1738 static noinline_for_stack
1739 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1740 struct btrfs_path *path, int level)
1742 struct btrfs_disk_key key1;
1743 struct btrfs_disk_key key2;
1744 btrfs_node_key(eb, &key1, slot);
1745 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1746 return memcmp(&key1, &key2, sizeof(key1));
1750 * try to replace tree blocks in fs tree with the new blocks
1751 * in reloc tree. tree blocks haven't been modified since the
1752 * reloc tree was create can be replaced.
1754 * if a block was replaced, level of the block + 1 is returned.
1755 * if no block got replaced, 0 is returned. if there are other
1756 * errors, a negative error number is returned.
1758 static noinline_for_stack
1759 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1760 struct btrfs_root *dest, struct btrfs_root *src,
1761 struct btrfs_path *path, struct btrfs_key *next_key,
1762 int lowest_level, int max_level)
1764 struct btrfs_fs_info *fs_info = dest->fs_info;
1765 struct extent_buffer *eb;
1766 struct extent_buffer *parent;
1767 struct btrfs_ref ref = { 0 };
1768 struct btrfs_key key;
1780 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1781 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1783 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1785 slot = path->slots[lowest_level];
1786 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1788 eb = btrfs_lock_root_node(dest);
1789 btrfs_set_lock_blocking_write(eb);
1790 level = btrfs_header_level(eb);
1792 if (level < lowest_level) {
1793 btrfs_tree_unlock(eb);
1794 free_extent_buffer(eb);
1799 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1802 btrfs_set_lock_blocking_write(eb);
1805 next_key->objectid = (u64)-1;
1806 next_key->type = (u8)-1;
1807 next_key->offset = (u64)-1;
1812 struct btrfs_key first_key;
1814 level = btrfs_header_level(parent);
1815 BUG_ON(level < lowest_level);
1817 ret = btrfs_bin_search(parent, &key, level, &slot);
1820 if (ret && slot > 0)
1823 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1824 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1826 old_bytenr = btrfs_node_blockptr(parent, slot);
1827 blocksize = fs_info->nodesize;
1828 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1829 btrfs_node_key_to_cpu(parent, &first_key, slot);
1831 if (level <= max_level) {
1832 eb = path->nodes[level];
1833 new_bytenr = btrfs_node_blockptr(eb,
1834 path->slots[level]);
1835 new_ptr_gen = btrfs_node_ptr_generation(eb,
1836 path->slots[level]);
1842 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1847 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1848 memcmp_node_keys(parent, slot, path, level)) {
1849 if (level <= lowest_level) {
1854 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1855 level - 1, &first_key);
1859 } else if (!extent_buffer_uptodate(eb)) {
1861 free_extent_buffer(eb);
1864 btrfs_tree_lock(eb);
1866 ret = btrfs_cow_block(trans, dest, eb, parent,
1870 btrfs_set_lock_blocking_write(eb);
1872 btrfs_tree_unlock(parent);
1873 free_extent_buffer(parent);
1880 btrfs_tree_unlock(parent);
1881 free_extent_buffer(parent);
1886 btrfs_node_key_to_cpu(path->nodes[level], &key,
1887 path->slots[level]);
1888 btrfs_release_path(path);
1890 path->lowest_level = level;
1891 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1892 path->lowest_level = 0;
1896 * Info qgroup to trace both subtrees.
1898 * We must trace both trees.
1899 * 1) Tree reloc subtree
1900 * If not traced, we will leak data numbers
1902 * If not traced, we will double count old data
1904 * We don't scan the subtree right now, but only record
1905 * the swapped tree blocks.
1906 * The real subtree rescan is delayed until we have new
1907 * CoW on the subtree root node before transaction commit.
1909 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1910 rc->block_group, parent, slot,
1911 path->nodes[level], path->slots[level],
1916 * swap blocks in fs tree and reloc tree.
1918 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1919 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1920 btrfs_mark_buffer_dirty(parent);
1922 btrfs_set_node_blockptr(path->nodes[level],
1923 path->slots[level], old_bytenr);
1924 btrfs_set_node_ptr_generation(path->nodes[level],
1925 path->slots[level], old_ptr_gen);
1926 btrfs_mark_buffer_dirty(path->nodes[level]);
1928 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1929 blocksize, path->nodes[level]->start);
1930 ref.skip_qgroup = true;
1931 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1932 ret = btrfs_inc_extent_ref(trans, &ref);
1934 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1936 ref.skip_qgroup = true;
1937 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1938 ret = btrfs_inc_extent_ref(trans, &ref);
1941 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1942 blocksize, path->nodes[level]->start);
1943 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1944 ref.skip_qgroup = true;
1945 ret = btrfs_free_extent(trans, &ref);
1948 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1950 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1951 ref.skip_qgroup = true;
1952 ret = btrfs_free_extent(trans, &ref);
1955 btrfs_unlock_up_safe(path, 0);
1960 btrfs_tree_unlock(parent);
1961 free_extent_buffer(parent);
1966 * helper to find next relocated block in reloc tree
1968 static noinline_for_stack
1969 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1972 struct extent_buffer *eb;
1977 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1979 for (i = 0; i < *level; i++) {
1980 free_extent_buffer(path->nodes[i]);
1981 path->nodes[i] = NULL;
1984 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
1985 eb = path->nodes[i];
1986 nritems = btrfs_header_nritems(eb);
1987 while (path->slots[i] + 1 < nritems) {
1989 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
1996 free_extent_buffer(path->nodes[i]);
1997 path->nodes[i] = NULL;
2003 * walk down reloc tree to find relocated block of lowest level
2005 static noinline_for_stack
2006 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2009 struct btrfs_fs_info *fs_info = root->fs_info;
2010 struct extent_buffer *eb = NULL;
2017 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2019 for (i = *level; i > 0; i--) {
2020 struct btrfs_key first_key;
2022 eb = path->nodes[i];
2023 nritems = btrfs_header_nritems(eb);
2024 while (path->slots[i] < nritems) {
2025 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2026 if (ptr_gen > last_snapshot)
2030 if (path->slots[i] >= nritems) {
2041 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2042 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2043 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2047 } else if (!extent_buffer_uptodate(eb)) {
2048 free_extent_buffer(eb);
2051 BUG_ON(btrfs_header_level(eb) != i - 1);
2052 path->nodes[i - 1] = eb;
2053 path->slots[i - 1] = 0;
2059 * invalidate extent cache for file extents whose key in range of
2060 * [min_key, max_key)
2062 static int invalidate_extent_cache(struct btrfs_root *root,
2063 struct btrfs_key *min_key,
2064 struct btrfs_key *max_key)
2066 struct btrfs_fs_info *fs_info = root->fs_info;
2067 struct inode *inode = NULL;
2072 objectid = min_key->objectid;
2077 if (objectid > max_key->objectid)
2080 inode = find_next_inode(root, objectid);
2083 ino = btrfs_ino(BTRFS_I(inode));
2085 if (ino > max_key->objectid) {
2091 if (!S_ISREG(inode->i_mode))
2094 if (unlikely(min_key->objectid == ino)) {
2095 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2097 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2100 start = min_key->offset;
2101 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2107 if (unlikely(max_key->objectid == ino)) {
2108 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2110 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2113 if (max_key->offset == 0)
2115 end = max_key->offset;
2116 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2123 /* the lock_extent waits for readpage to complete */
2124 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2125 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2126 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2131 static int find_next_key(struct btrfs_path *path, int level,
2132 struct btrfs_key *key)
2135 while (level < BTRFS_MAX_LEVEL) {
2136 if (!path->nodes[level])
2138 if (path->slots[level] + 1 <
2139 btrfs_header_nritems(path->nodes[level])) {
2140 btrfs_node_key_to_cpu(path->nodes[level], key,
2141 path->slots[level] + 1);
2150 * Insert current subvolume into reloc_control::dirty_subvol_roots
2152 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2153 struct reloc_control *rc,
2154 struct btrfs_root *root)
2156 struct btrfs_root *reloc_root = root->reloc_root;
2157 struct btrfs_root_item *reloc_root_item;
2159 /* @root must be a subvolume tree root with a valid reloc tree */
2160 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2163 reloc_root_item = &reloc_root->root_item;
2164 memset(&reloc_root_item->drop_progress, 0,
2165 sizeof(reloc_root_item->drop_progress));
2166 reloc_root_item->drop_level = 0;
2167 btrfs_set_root_refs(reloc_root_item, 0);
2168 btrfs_update_reloc_root(trans, root);
2170 if (list_empty(&root->reloc_dirty_list)) {
2171 btrfs_grab_fs_root(root);
2172 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2176 static int clean_dirty_subvols(struct reloc_control *rc)
2178 struct btrfs_root *root;
2179 struct btrfs_root *next;
2183 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2185 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2186 /* Merged subvolume, cleanup its reloc root */
2187 struct btrfs_root *reloc_root = root->reloc_root;
2189 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2190 list_del_init(&root->reloc_dirty_list);
2191 root->reloc_root = NULL;
2194 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2195 if (ret2 < 0 && !ret)
2198 btrfs_put_fs_root(root);
2200 /* Orphan reloc tree, just clean it up */
2201 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2202 if (ret2 < 0 && !ret)
2210 * merge the relocated tree blocks in reloc tree with corresponding
2213 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2214 struct btrfs_root *root)
2216 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2217 struct btrfs_key key;
2218 struct btrfs_key next_key;
2219 struct btrfs_trans_handle *trans = NULL;
2220 struct btrfs_root *reloc_root;
2221 struct btrfs_root_item *root_item;
2222 struct btrfs_path *path;
2223 struct extent_buffer *leaf;
2231 path = btrfs_alloc_path();
2234 path->reada = READA_FORWARD;
2236 reloc_root = root->reloc_root;
2237 root_item = &reloc_root->root_item;
2239 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2240 level = btrfs_root_level(root_item);
2241 extent_buffer_get(reloc_root->node);
2242 path->nodes[level] = reloc_root->node;
2243 path->slots[level] = 0;
2245 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2247 level = root_item->drop_level;
2249 path->lowest_level = level;
2250 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2251 path->lowest_level = 0;
2253 btrfs_free_path(path);
2257 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2258 path->slots[level]);
2259 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2261 btrfs_unlock_up_safe(path, 0);
2264 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2265 memset(&next_key, 0, sizeof(next_key));
2268 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2269 BTRFS_RESERVE_FLUSH_ALL);
2274 trans = btrfs_start_transaction(root, 0);
2275 if (IS_ERR(trans)) {
2276 err = PTR_ERR(trans);
2280 trans->block_rsv = rc->block_rsv;
2285 ret = walk_down_reloc_tree(reloc_root, path, &level);
2293 if (!find_next_key(path, level, &key) &&
2294 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2297 ret = replace_path(trans, rc, root, reloc_root, path,
2298 &next_key, level, max_level);
2307 btrfs_node_key_to_cpu(path->nodes[level], &key,
2308 path->slots[level]);
2312 ret = walk_up_reloc_tree(reloc_root, path, &level);
2318 * save the merging progress in the drop_progress.
2319 * this is OK since root refs == 1 in this case.
2321 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2322 path->slots[level]);
2323 root_item->drop_level = level;
2325 btrfs_end_transaction_throttle(trans);
2328 btrfs_btree_balance_dirty(fs_info);
2330 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2331 invalidate_extent_cache(root, &key, &next_key);
2335 * handle the case only one block in the fs tree need to be
2336 * relocated and the block is tree root.
2338 leaf = btrfs_lock_root_node(root);
2339 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2340 btrfs_tree_unlock(leaf);
2341 free_extent_buffer(leaf);
2345 btrfs_free_path(path);
2348 insert_dirty_subvol(trans, rc, root);
2351 btrfs_end_transaction_throttle(trans);
2353 btrfs_btree_balance_dirty(fs_info);
2355 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2356 invalidate_extent_cache(root, &key, &next_key);
2361 static noinline_for_stack
2362 int prepare_to_merge(struct reloc_control *rc, int err)
2364 struct btrfs_root *root = rc->extent_root;
2365 struct btrfs_fs_info *fs_info = root->fs_info;
2366 struct btrfs_root *reloc_root;
2367 struct btrfs_trans_handle *trans;
2368 LIST_HEAD(reloc_roots);
2372 mutex_lock(&fs_info->reloc_mutex);
2373 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2374 rc->merging_rsv_size += rc->nodes_relocated * 2;
2375 mutex_unlock(&fs_info->reloc_mutex);
2379 num_bytes = rc->merging_rsv_size;
2380 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2381 BTRFS_RESERVE_FLUSH_ALL);
2386 trans = btrfs_join_transaction(rc->extent_root);
2387 if (IS_ERR(trans)) {
2389 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2391 return PTR_ERR(trans);
2395 if (num_bytes != rc->merging_rsv_size) {
2396 btrfs_end_transaction(trans);
2397 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2403 rc->merge_reloc_tree = 1;
2405 while (!list_empty(&rc->reloc_roots)) {
2406 reloc_root = list_entry(rc->reloc_roots.next,
2407 struct btrfs_root, root_list);
2408 list_del_init(&reloc_root->root_list);
2410 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2411 BUG_ON(IS_ERR(root));
2412 BUG_ON(root->reloc_root != reloc_root);
2415 * set reference count to 1, so btrfs_recover_relocation
2416 * knows it should resumes merging
2419 btrfs_set_root_refs(&reloc_root->root_item, 1);
2420 btrfs_update_reloc_root(trans, root);
2422 list_add(&reloc_root->root_list, &reloc_roots);
2425 list_splice(&reloc_roots, &rc->reloc_roots);
2428 btrfs_commit_transaction(trans);
2430 btrfs_end_transaction(trans);
2434 static noinline_for_stack
2435 void free_reloc_roots(struct list_head *list)
2437 struct btrfs_root *reloc_root;
2439 while (!list_empty(list)) {
2440 reloc_root = list_entry(list->next, struct btrfs_root,
2442 __del_reloc_root(reloc_root);
2443 free_extent_buffer(reloc_root->node);
2444 free_extent_buffer(reloc_root->commit_root);
2445 reloc_root->node = NULL;
2446 reloc_root->commit_root = NULL;
2450 static noinline_for_stack
2451 void merge_reloc_roots(struct reloc_control *rc)
2453 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2454 struct btrfs_root *root;
2455 struct btrfs_root *reloc_root;
2456 LIST_HEAD(reloc_roots);
2460 root = rc->extent_root;
2463 * this serializes us with btrfs_record_root_in_transaction,
2464 * we have to make sure nobody is in the middle of
2465 * adding their roots to the list while we are
2468 mutex_lock(&fs_info->reloc_mutex);
2469 list_splice_init(&rc->reloc_roots, &reloc_roots);
2470 mutex_unlock(&fs_info->reloc_mutex);
2472 while (!list_empty(&reloc_roots)) {
2474 reloc_root = list_entry(reloc_roots.next,
2475 struct btrfs_root, root_list);
2477 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2478 root = read_fs_root(fs_info,
2479 reloc_root->root_key.offset);
2480 BUG_ON(IS_ERR(root));
2481 BUG_ON(root->reloc_root != reloc_root);
2483 ret = merge_reloc_root(rc, root);
2485 if (list_empty(&reloc_root->root_list))
2486 list_add_tail(&reloc_root->root_list,
2491 list_del_init(&reloc_root->root_list);
2492 /* Don't forget to queue this reloc root for cleanup */
2493 list_add_tail(&reloc_root->reloc_dirty_list,
2494 &rc->dirty_subvol_roots);
2504 btrfs_handle_fs_error(fs_info, ret, NULL);
2505 if (!list_empty(&reloc_roots))
2506 free_reloc_roots(&reloc_roots);
2508 /* new reloc root may be added */
2509 mutex_lock(&fs_info->reloc_mutex);
2510 list_splice_init(&rc->reloc_roots, &reloc_roots);
2511 mutex_unlock(&fs_info->reloc_mutex);
2512 if (!list_empty(&reloc_roots))
2513 free_reloc_roots(&reloc_roots);
2516 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2519 static void free_block_list(struct rb_root *blocks)
2521 struct tree_block *block;
2522 struct rb_node *rb_node;
2523 while ((rb_node = rb_first(blocks))) {
2524 block = rb_entry(rb_node, struct tree_block, rb_node);
2525 rb_erase(rb_node, blocks);
2530 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2531 struct btrfs_root *reloc_root)
2533 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2534 struct btrfs_root *root;
2536 if (reloc_root->last_trans == trans->transid)
2539 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2540 BUG_ON(IS_ERR(root));
2541 BUG_ON(root->reloc_root != reloc_root);
2543 return btrfs_record_root_in_trans(trans, root);
2546 static noinline_for_stack
2547 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2548 struct reloc_control *rc,
2549 struct backref_node *node,
2550 struct backref_edge *edges[])
2552 struct backref_node *next;
2553 struct btrfs_root *root;
2559 next = walk_up_backref(next, edges, &index);
2562 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2564 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2565 record_reloc_root_in_trans(trans, root);
2569 btrfs_record_root_in_trans(trans, root);
2570 root = root->reloc_root;
2572 if (next->new_bytenr != root->node->start) {
2573 BUG_ON(next->new_bytenr);
2574 BUG_ON(!list_empty(&next->list));
2575 next->new_bytenr = root->node->start;
2577 list_add_tail(&next->list,
2578 &rc->backref_cache.changed);
2579 __mark_block_processed(rc, next);
2585 next = walk_down_backref(edges, &index);
2586 if (!next || next->level <= node->level)
2593 /* setup backref node path for btrfs_reloc_cow_block */
2595 rc->backref_cache.path[next->level] = next;
2598 next = edges[index]->node[UPPER];
2604 * select a tree root for relocation. return NULL if the block
2605 * is reference counted. we should use do_relocation() in this
2606 * case. return a tree root pointer if the block isn't reference
2607 * counted. return -ENOENT if the block is root of reloc tree.
2609 static noinline_for_stack
2610 struct btrfs_root *select_one_root(struct backref_node *node)
2612 struct backref_node *next;
2613 struct btrfs_root *root;
2614 struct btrfs_root *fs_root = NULL;
2615 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2621 next = walk_up_backref(next, edges, &index);
2625 /* no other choice for non-references counted tree */
2626 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2629 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2635 next = walk_down_backref(edges, &index);
2636 if (!next || next->level <= node->level)
2641 return ERR_PTR(-ENOENT);
2645 static noinline_for_stack
2646 u64 calcu_metadata_size(struct reloc_control *rc,
2647 struct backref_node *node, int reserve)
2649 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2650 struct backref_node *next = node;
2651 struct backref_edge *edge;
2652 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2656 BUG_ON(reserve && node->processed);
2661 if (next->processed && (reserve || next != node))
2664 num_bytes += fs_info->nodesize;
2666 if (list_empty(&next->upper))
2669 edge = list_entry(next->upper.next,
2670 struct backref_edge, list[LOWER]);
2671 edges[index++] = edge;
2672 next = edge->node[UPPER];
2674 next = walk_down_backref(edges, &index);
2679 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2680 struct reloc_control *rc,
2681 struct backref_node *node)
2683 struct btrfs_root *root = rc->extent_root;
2684 struct btrfs_fs_info *fs_info = root->fs_info;
2689 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2691 trans->block_rsv = rc->block_rsv;
2692 rc->reserved_bytes += num_bytes;
2695 * We are under a transaction here so we can only do limited flushing.
2696 * If we get an enospc just kick back -EAGAIN so we know to drop the
2697 * transaction and try to refill when we can flush all the things.
2699 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2700 BTRFS_RESERVE_FLUSH_LIMIT);
2702 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2703 while (tmp <= rc->reserved_bytes)
2706 * only one thread can access block_rsv at this point,
2707 * so we don't need hold lock to protect block_rsv.
2708 * we expand more reservation size here to allow enough
2709 * space for relocation and we will return earlier in
2712 rc->block_rsv->size = tmp + fs_info->nodesize *
2713 RELOCATION_RESERVED_NODES;
2721 * relocate a block tree, and then update pointers in upper level
2722 * blocks that reference the block to point to the new location.
2724 * if called by link_to_upper, the block has already been relocated.
2725 * in that case this function just updates pointers.
2727 static int do_relocation(struct btrfs_trans_handle *trans,
2728 struct reloc_control *rc,
2729 struct backref_node *node,
2730 struct btrfs_key *key,
2731 struct btrfs_path *path, int lowest)
2733 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2734 struct backref_node *upper;
2735 struct backref_edge *edge;
2736 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2737 struct btrfs_root *root;
2738 struct extent_buffer *eb;
2746 BUG_ON(lowest && node->eb);
2748 path->lowest_level = node->level + 1;
2749 rc->backref_cache.path[node->level] = node;
2750 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2751 struct btrfs_key first_key;
2752 struct btrfs_ref ref = { 0 };
2756 upper = edge->node[UPPER];
2757 root = select_reloc_root(trans, rc, upper, edges);
2760 if (upper->eb && !upper->locked) {
2762 ret = btrfs_bin_search(upper->eb, key,
2763 upper->level, &slot);
2769 bytenr = btrfs_node_blockptr(upper->eb, slot);
2770 if (node->eb->start == bytenr)
2773 drop_node_buffer(upper);
2777 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2784 btrfs_release_path(path);
2789 upper->eb = path->nodes[upper->level];
2790 path->nodes[upper->level] = NULL;
2792 BUG_ON(upper->eb != path->nodes[upper->level]);
2796 path->locks[upper->level] = 0;
2798 slot = path->slots[upper->level];
2799 btrfs_release_path(path);
2801 ret = btrfs_bin_search(upper->eb, key, upper->level,
2810 bytenr = btrfs_node_blockptr(upper->eb, slot);
2812 if (bytenr != node->bytenr) {
2813 btrfs_err(root->fs_info,
2814 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2815 bytenr, node->bytenr, slot,
2821 if (node->eb->start == bytenr)
2825 blocksize = root->fs_info->nodesize;
2826 generation = btrfs_node_ptr_generation(upper->eb, slot);
2827 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2828 eb = read_tree_block(fs_info, bytenr, generation,
2829 upper->level - 1, &first_key);
2833 } else if (!extent_buffer_uptodate(eb)) {
2834 free_extent_buffer(eb);
2838 btrfs_tree_lock(eb);
2839 btrfs_set_lock_blocking_write(eb);
2842 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2844 btrfs_tree_unlock(eb);
2845 free_extent_buffer(eb);
2850 BUG_ON(node->eb != eb);
2852 btrfs_set_node_blockptr(upper->eb, slot,
2854 btrfs_set_node_ptr_generation(upper->eb, slot,
2856 btrfs_mark_buffer_dirty(upper->eb);
2858 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2859 node->eb->start, blocksize,
2861 ref.real_root = root->root_key.objectid;
2862 btrfs_init_tree_ref(&ref, node->level,
2863 btrfs_header_owner(upper->eb));
2864 ret = btrfs_inc_extent_ref(trans, &ref);
2867 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2871 if (!upper->pending)
2872 drop_node_buffer(upper);
2874 unlock_node_buffer(upper);
2879 if (!err && node->pending) {
2880 drop_node_buffer(node);
2881 list_move_tail(&node->list, &rc->backref_cache.changed);
2885 path->lowest_level = 0;
2886 BUG_ON(err == -ENOSPC);
2890 static int link_to_upper(struct btrfs_trans_handle *trans,
2891 struct reloc_control *rc,
2892 struct backref_node *node,
2893 struct btrfs_path *path)
2895 struct btrfs_key key;
2897 btrfs_node_key_to_cpu(node->eb, &key, 0);
2898 return do_relocation(trans, rc, node, &key, path, 0);
2901 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2902 struct reloc_control *rc,
2903 struct btrfs_path *path, int err)
2906 struct backref_cache *cache = &rc->backref_cache;
2907 struct backref_node *node;
2911 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2912 while (!list_empty(&cache->pending[level])) {
2913 node = list_entry(cache->pending[level].next,
2914 struct backref_node, list);
2915 list_move_tail(&node->list, &list);
2916 BUG_ON(!node->pending);
2919 ret = link_to_upper(trans, rc, node, path);
2924 list_splice_init(&list, &cache->pending[level]);
2929 static void mark_block_processed(struct reloc_control *rc,
2930 u64 bytenr, u32 blocksize)
2932 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2936 static void __mark_block_processed(struct reloc_control *rc,
2937 struct backref_node *node)
2940 if (node->level == 0 ||
2941 in_block_group(node->bytenr, rc->block_group)) {
2942 blocksize = rc->extent_root->fs_info->nodesize;
2943 mark_block_processed(rc, node->bytenr, blocksize);
2945 node->processed = 1;
2949 * mark a block and all blocks directly/indirectly reference the block
2952 static void update_processed_blocks(struct reloc_control *rc,
2953 struct backref_node *node)
2955 struct backref_node *next = node;
2956 struct backref_edge *edge;
2957 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2963 if (next->processed)
2966 __mark_block_processed(rc, next);
2968 if (list_empty(&next->upper))
2971 edge = list_entry(next->upper.next,
2972 struct backref_edge, list[LOWER]);
2973 edges[index++] = edge;
2974 next = edge->node[UPPER];
2976 next = walk_down_backref(edges, &index);
2980 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2982 u32 blocksize = rc->extent_root->fs_info->nodesize;
2984 if (test_range_bit(&rc->processed_blocks, bytenr,
2985 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2990 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2991 struct tree_block *block)
2993 struct extent_buffer *eb;
2995 BUG_ON(block->key_ready);
2996 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
2997 block->level, NULL);
3000 } else if (!extent_buffer_uptodate(eb)) {
3001 free_extent_buffer(eb);
3004 if (block->level == 0)
3005 btrfs_item_key_to_cpu(eb, &block->key, 0);
3007 btrfs_node_key_to_cpu(eb, &block->key, 0);
3008 free_extent_buffer(eb);
3009 block->key_ready = 1;
3014 * helper function to relocate a tree block
3016 static int relocate_tree_block(struct btrfs_trans_handle *trans,
3017 struct reloc_control *rc,
3018 struct backref_node *node,
3019 struct btrfs_key *key,
3020 struct btrfs_path *path)
3022 struct btrfs_root *root;
3028 BUG_ON(node->processed);
3029 root = select_one_root(node);
3030 if (root == ERR_PTR(-ENOENT)) {
3031 update_processed_blocks(rc, node);
3035 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3036 ret = reserve_metadata_space(trans, rc, node);
3042 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3043 BUG_ON(node->new_bytenr);
3044 BUG_ON(!list_empty(&node->list));
3045 btrfs_record_root_in_trans(trans, root);
3046 root = root->reloc_root;
3047 node->new_bytenr = root->node->start;
3049 list_add_tail(&node->list, &rc->backref_cache.changed);
3051 path->lowest_level = node->level;
3052 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3053 btrfs_release_path(path);
3058 update_processed_blocks(rc, node);
3060 ret = do_relocation(trans, rc, node, key, path, 1);
3063 if (ret || node->level == 0 || node->cowonly)
3064 remove_backref_node(&rc->backref_cache, node);
3069 * relocate a list of blocks
3071 static noinline_for_stack
3072 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3073 struct reloc_control *rc, struct rb_root *blocks)
3075 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3076 struct backref_node *node;
3077 struct btrfs_path *path;
3078 struct tree_block *block;
3079 struct tree_block *next;
3083 path = btrfs_alloc_path();
3086 goto out_free_blocks;
3089 /* Kick in readahead for tree blocks with missing keys */
3090 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3091 if (!block->key_ready)
3092 readahead_tree_block(fs_info, block->bytenr);
3095 /* Get first keys */
3096 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3097 if (!block->key_ready) {
3098 err = get_tree_block_key(fs_info, block);
3104 /* Do tree relocation */
3105 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3106 node = build_backref_tree(rc, &block->key,
3107 block->level, block->bytenr);
3109 err = PTR_ERR(node);
3113 ret = relocate_tree_block(trans, rc, node, &block->key,
3116 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3122 err = finish_pending_nodes(trans, rc, path, err);
3125 btrfs_free_path(path);
3127 free_block_list(blocks);
3131 static noinline_for_stack
3132 int prealloc_file_extent_cluster(struct inode *inode,
3133 struct file_extent_cluster *cluster)
3138 u64 offset = BTRFS_I(inode)->index_cnt;
3142 u64 prealloc_start = cluster->start - offset;
3143 u64 prealloc_end = cluster->end - offset;
3145 struct extent_changeset *data_reserved = NULL;
3147 BUG_ON(cluster->start != cluster->boundary[0]);
3150 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3151 prealloc_end + 1 - prealloc_start);
3155 cur_offset = prealloc_start;
3156 while (nr < cluster->nr) {
3157 start = cluster->boundary[nr] - offset;
3158 if (nr + 1 < cluster->nr)
3159 end = cluster->boundary[nr + 1] - 1 - offset;
3161 end = cluster->end - offset;
3163 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3164 num_bytes = end + 1 - start;
3165 if (cur_offset < start)
3166 btrfs_free_reserved_data_space(inode, data_reserved,
3167 cur_offset, start - cur_offset);
3168 ret = btrfs_prealloc_file_range(inode, 0, start,
3169 num_bytes, num_bytes,
3170 end + 1, &alloc_hint);
3171 cur_offset = end + 1;
3172 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3177 if (cur_offset < prealloc_end)
3178 btrfs_free_reserved_data_space(inode, data_reserved,
3179 cur_offset, prealloc_end + 1 - cur_offset);
3181 inode_unlock(inode);
3182 extent_changeset_free(data_reserved);
3186 static noinline_for_stack
3187 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3190 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3191 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3192 struct extent_map *em;
3195 em = alloc_extent_map();
3200 em->len = end + 1 - start;
3201 em->block_len = em->len;
3202 em->block_start = block_start;
3203 em->bdev = fs_info->fs_devices->latest_bdev;
3204 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3206 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3208 write_lock(&em_tree->lock);
3209 ret = add_extent_mapping(em_tree, em, 0);
3210 write_unlock(&em_tree->lock);
3211 if (ret != -EEXIST) {
3212 free_extent_map(em);
3215 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3217 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3221 static int relocate_file_extent_cluster(struct inode *inode,
3222 struct file_extent_cluster *cluster)
3224 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3227 u64 offset = BTRFS_I(inode)->index_cnt;
3228 unsigned long index;
3229 unsigned long last_index;
3231 struct file_ra_state *ra;
3232 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3239 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3243 ret = prealloc_file_extent_cluster(inode, cluster);
3247 file_ra_state_init(ra, inode->i_mapping);
3249 ret = setup_extent_mapping(inode, cluster->start - offset,
3250 cluster->end - offset, cluster->start);
3254 index = (cluster->start - offset) >> PAGE_SHIFT;
3255 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3256 while (index <= last_index) {
3257 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3262 page = find_lock_page(inode->i_mapping, index);
3264 page_cache_sync_readahead(inode->i_mapping,
3266 last_index + 1 - index);
3267 page = find_or_create_page(inode->i_mapping, index,
3270 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3277 if (PageReadahead(page)) {
3278 page_cache_async_readahead(inode->i_mapping,
3279 ra, NULL, page, index,
3280 last_index + 1 - index);
3283 if (!PageUptodate(page)) {
3284 btrfs_readpage(NULL, page);
3286 if (!PageUptodate(page)) {
3289 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3291 btrfs_delalloc_release_extents(BTRFS_I(inode),
3298 page_start = page_offset(page);
3299 page_end = page_start + PAGE_SIZE - 1;
3301 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3303 set_page_extent_mapped(page);
3305 if (nr < cluster->nr &&
3306 page_start + offset == cluster->boundary[nr]) {
3307 set_extent_bits(&BTRFS_I(inode)->io_tree,
3308 page_start, page_end,
3313 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3318 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3320 btrfs_delalloc_release_extents(BTRFS_I(inode),
3323 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3324 page_start, page_end,
3325 EXTENT_LOCKED | EXTENT_BOUNDARY);
3329 set_page_dirty(page);
3331 unlock_extent(&BTRFS_I(inode)->io_tree,
3332 page_start, page_end);
3337 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE,
3339 balance_dirty_pages_ratelimited(inode->i_mapping);
3340 btrfs_throttle(fs_info);
3342 WARN_ON(nr != cluster->nr);
3348 static noinline_for_stack
3349 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3350 struct file_extent_cluster *cluster)
3354 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3355 ret = relocate_file_extent_cluster(inode, cluster);
3362 cluster->start = extent_key->objectid;
3364 BUG_ON(cluster->nr >= MAX_EXTENTS);
3365 cluster->end = extent_key->objectid + extent_key->offset - 1;
3366 cluster->boundary[cluster->nr] = extent_key->objectid;
3369 if (cluster->nr >= MAX_EXTENTS) {
3370 ret = relocate_file_extent_cluster(inode, cluster);
3379 * helper to add a tree block to the list.
3380 * the major work is getting the generation and level of the block
3382 static int add_tree_block(struct reloc_control *rc,
3383 struct btrfs_key *extent_key,
3384 struct btrfs_path *path,
3385 struct rb_root *blocks)
3387 struct extent_buffer *eb;
3388 struct btrfs_extent_item *ei;
3389 struct btrfs_tree_block_info *bi;
3390 struct tree_block *block;
3391 struct rb_node *rb_node;
3396 eb = path->nodes[0];
3397 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3399 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3400 item_size >= sizeof(*ei) + sizeof(*bi)) {
3401 ei = btrfs_item_ptr(eb, path->slots[0],
3402 struct btrfs_extent_item);
3403 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3404 bi = (struct btrfs_tree_block_info *)(ei + 1);
3405 level = btrfs_tree_block_level(eb, bi);
3407 level = (int)extent_key->offset;
3409 generation = btrfs_extent_generation(eb, ei);
3410 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3411 btrfs_print_v0_err(eb->fs_info);
3412 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3418 btrfs_release_path(path);
3420 BUG_ON(level == -1);
3422 block = kmalloc(sizeof(*block), GFP_NOFS);
3426 block->bytenr = extent_key->objectid;
3427 block->key.objectid = rc->extent_root->fs_info->nodesize;
3428 block->key.offset = generation;
3429 block->level = level;
3430 block->key_ready = 0;
3432 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3434 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3440 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3442 static int __add_tree_block(struct reloc_control *rc,
3443 u64 bytenr, u32 blocksize,
3444 struct rb_root *blocks)
3446 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3447 struct btrfs_path *path;
3448 struct btrfs_key key;
3450 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3452 if (tree_block_processed(bytenr, rc))
3455 if (tree_search(blocks, bytenr))
3458 path = btrfs_alloc_path();
3462 key.objectid = bytenr;
3464 key.type = BTRFS_METADATA_ITEM_KEY;
3465 key.offset = (u64)-1;
3467 key.type = BTRFS_EXTENT_ITEM_KEY;
3468 key.offset = blocksize;
3471 path->search_commit_root = 1;
3472 path->skip_locking = 1;
3473 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3477 if (ret > 0 && skinny) {
3478 if (path->slots[0]) {
3480 btrfs_item_key_to_cpu(path->nodes[0], &key,
3482 if (key.objectid == bytenr &&
3483 (key.type == BTRFS_METADATA_ITEM_KEY ||
3484 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3485 key.offset == blocksize)))
3491 btrfs_release_path(path);
3497 btrfs_print_leaf(path->nodes[0]);
3499 "tree block extent item (%llu) is not found in extent tree",
3506 ret = add_tree_block(rc, &key, path, blocks);
3508 btrfs_free_path(path);
3513 * helper to check if the block use full backrefs for pointers in it
3515 static int block_use_full_backref(struct reloc_control *rc,
3516 struct extent_buffer *eb)
3521 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3522 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3525 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3526 eb->start, btrfs_header_level(eb), 1,
3530 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3537 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3538 struct btrfs_block_group_cache *block_group,
3539 struct inode *inode,
3542 struct btrfs_key key;
3543 struct btrfs_root *root = fs_info->tree_root;
3544 struct btrfs_trans_handle *trans;
3551 key.type = BTRFS_INODE_ITEM_KEY;
3554 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3559 ret = btrfs_check_trunc_cache_free_space(fs_info,
3560 &fs_info->global_block_rsv);
3564 trans = btrfs_join_transaction(root);
3565 if (IS_ERR(trans)) {
3566 ret = PTR_ERR(trans);
3570 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3572 btrfs_end_transaction(trans);
3573 btrfs_btree_balance_dirty(fs_info);
3580 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3581 * this function scans fs tree to find blocks reference the data extent
3583 static int find_data_references(struct reloc_control *rc,
3584 struct btrfs_key *extent_key,
3585 struct extent_buffer *leaf,
3586 struct btrfs_extent_data_ref *ref,
3587 struct rb_root *blocks)
3589 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3590 struct btrfs_path *path;
3591 struct tree_block *block;
3592 struct btrfs_root *root;
3593 struct btrfs_file_extent_item *fi;
3594 struct rb_node *rb_node;
3595 struct btrfs_key key;
3606 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3607 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3608 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3609 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3612 * This is an extent belonging to the free space cache, lets just delete
3613 * it and redo the search.
3615 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3616 ret = delete_block_group_cache(fs_info, rc->block_group,
3617 NULL, ref_objectid);
3623 path = btrfs_alloc_path();
3626 path->reada = READA_FORWARD;
3628 root = read_fs_root(fs_info, ref_root);
3630 err = PTR_ERR(root);
3634 key.objectid = ref_objectid;
3635 key.type = BTRFS_EXTENT_DATA_KEY;
3636 if (ref_offset > ((u64)-1 << 32))
3639 key.offset = ref_offset;
3641 path->search_commit_root = 1;
3642 path->skip_locking = 1;
3643 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3649 leaf = path->nodes[0];
3650 nritems = btrfs_header_nritems(leaf);
3652 * the references in tree blocks that use full backrefs
3653 * are not counted in
3655 if (block_use_full_backref(rc, leaf))
3659 rb_node = tree_search(blocks, leaf->start);
3664 path->slots[0] = nritems;
3667 while (ref_count > 0) {
3668 while (path->slots[0] >= nritems) {
3669 ret = btrfs_next_leaf(root, path);
3674 if (WARN_ON(ret > 0))
3677 leaf = path->nodes[0];
3678 nritems = btrfs_header_nritems(leaf);
3681 if (block_use_full_backref(rc, leaf))
3685 rb_node = tree_search(blocks, leaf->start);
3690 path->slots[0] = nritems;
3694 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3695 if (WARN_ON(key.objectid != ref_objectid ||
3696 key.type != BTRFS_EXTENT_DATA_KEY))
3699 fi = btrfs_item_ptr(leaf, path->slots[0],
3700 struct btrfs_file_extent_item);
3702 if (btrfs_file_extent_type(leaf, fi) ==
3703 BTRFS_FILE_EXTENT_INLINE)
3706 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3707 extent_key->objectid)
3710 key.offset -= btrfs_file_extent_offset(leaf, fi);
3711 if (key.offset != ref_offset)
3719 if (!tree_block_processed(leaf->start, rc)) {
3720 block = kmalloc(sizeof(*block), GFP_NOFS);
3725 block->bytenr = leaf->start;
3726 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3728 block->key_ready = 1;
3729 rb_node = tree_insert(blocks, block->bytenr,
3732 backref_tree_panic(rb_node, -EEXIST,
3738 path->slots[0] = nritems;
3744 btrfs_free_path(path);
3749 * helper to find all tree blocks that reference a given data extent
3751 static noinline_for_stack
3752 int add_data_references(struct reloc_control *rc,
3753 struct btrfs_key *extent_key,
3754 struct btrfs_path *path,
3755 struct rb_root *blocks)
3757 struct btrfs_key key;
3758 struct extent_buffer *eb;
3759 struct btrfs_extent_data_ref *dref;
3760 struct btrfs_extent_inline_ref *iref;
3763 u32 blocksize = rc->extent_root->fs_info->nodesize;
3767 eb = path->nodes[0];
3768 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3769 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3770 ptr += sizeof(struct btrfs_extent_item);
3773 iref = (struct btrfs_extent_inline_ref *)ptr;
3774 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3775 BTRFS_REF_TYPE_DATA);
3776 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3777 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3778 ret = __add_tree_block(rc, key.offset, blocksize,
3780 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3781 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3782 ret = find_data_references(rc, extent_key,
3786 btrfs_err(rc->extent_root->fs_info,
3787 "extent %llu slot %d has an invalid inline ref type",
3788 eb->start, path->slots[0]);
3794 ptr += btrfs_extent_inline_ref_size(key.type);
3800 eb = path->nodes[0];
3801 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3802 ret = btrfs_next_leaf(rc->extent_root, path);
3809 eb = path->nodes[0];
3812 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3813 if (key.objectid != extent_key->objectid)
3816 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3817 ret = __add_tree_block(rc, key.offset, blocksize,
3819 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3820 dref = btrfs_item_ptr(eb, path->slots[0],
3821 struct btrfs_extent_data_ref);
3822 ret = find_data_references(rc, extent_key,
3824 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3825 btrfs_print_v0_err(eb->fs_info);
3826 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3838 btrfs_release_path(path);
3840 free_block_list(blocks);
3845 * helper to find next unprocessed extent
3847 static noinline_for_stack
3848 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3849 struct btrfs_key *extent_key)
3851 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3852 struct btrfs_key key;
3853 struct extent_buffer *leaf;
3854 u64 start, end, last;
3857 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3860 if (rc->search_start >= last) {
3865 key.objectid = rc->search_start;
3866 key.type = BTRFS_EXTENT_ITEM_KEY;
3869 path->search_commit_root = 1;
3870 path->skip_locking = 1;
3871 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3876 leaf = path->nodes[0];
3877 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3878 ret = btrfs_next_leaf(rc->extent_root, path);
3881 leaf = path->nodes[0];
3884 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3885 if (key.objectid >= last) {
3890 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3891 key.type != BTRFS_METADATA_ITEM_KEY) {
3896 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3897 key.objectid + key.offset <= rc->search_start) {
3902 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3903 key.objectid + fs_info->nodesize <=
3909 ret = find_first_extent_bit(&rc->processed_blocks,
3910 key.objectid, &start, &end,
3911 EXTENT_DIRTY, NULL);
3913 if (ret == 0 && start <= key.objectid) {
3914 btrfs_release_path(path);
3915 rc->search_start = end + 1;
3917 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3918 rc->search_start = key.objectid + key.offset;
3920 rc->search_start = key.objectid +
3922 memcpy(extent_key, &key, sizeof(key));
3926 btrfs_release_path(path);
3930 static void set_reloc_control(struct reloc_control *rc)
3932 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3934 mutex_lock(&fs_info->reloc_mutex);
3935 fs_info->reloc_ctl = rc;
3936 mutex_unlock(&fs_info->reloc_mutex);
3939 static void unset_reloc_control(struct reloc_control *rc)
3941 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3943 mutex_lock(&fs_info->reloc_mutex);
3944 fs_info->reloc_ctl = NULL;
3945 mutex_unlock(&fs_info->reloc_mutex);
3948 static int check_extent_flags(u64 flags)
3950 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3951 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3953 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3954 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3956 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3957 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3962 static noinline_for_stack
3963 int prepare_to_relocate(struct reloc_control *rc)
3965 struct btrfs_trans_handle *trans;
3968 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3969 BTRFS_BLOCK_RSV_TEMP);
3973 memset(&rc->cluster, 0, sizeof(rc->cluster));
3974 rc->search_start = rc->block_group->key.objectid;
3975 rc->extents_found = 0;
3976 rc->nodes_relocated = 0;
3977 rc->merging_rsv_size = 0;
3978 rc->reserved_bytes = 0;
3979 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3980 RELOCATION_RESERVED_NODES;
3981 ret = btrfs_block_rsv_refill(rc->extent_root,
3982 rc->block_rsv, rc->block_rsv->size,
3983 BTRFS_RESERVE_FLUSH_ALL);
3987 rc->create_reloc_tree = 1;
3988 set_reloc_control(rc);
3990 trans = btrfs_join_transaction(rc->extent_root);
3991 if (IS_ERR(trans)) {
3992 unset_reloc_control(rc);
3994 * extent tree is not a ref_cow tree and has no reloc_root to
3995 * cleanup. And callers are responsible to free the above
3998 return PTR_ERR(trans);
4000 btrfs_commit_transaction(trans);
4004 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4006 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4007 struct rb_root blocks = RB_ROOT;
4008 struct btrfs_key key;
4009 struct btrfs_trans_handle *trans = NULL;
4010 struct btrfs_path *path;
4011 struct btrfs_extent_item *ei;
4018 path = btrfs_alloc_path();
4021 path->reada = READA_FORWARD;
4023 ret = prepare_to_relocate(rc);
4030 rc->reserved_bytes = 0;
4031 ret = btrfs_block_rsv_refill(rc->extent_root,
4032 rc->block_rsv, rc->block_rsv->size,
4033 BTRFS_RESERVE_FLUSH_ALL);
4039 trans = btrfs_start_transaction(rc->extent_root, 0);
4040 if (IS_ERR(trans)) {
4041 err = PTR_ERR(trans);
4046 if (update_backref_cache(trans, &rc->backref_cache)) {
4047 btrfs_end_transaction(trans);
4052 ret = find_next_extent(rc, path, &key);
4058 rc->extents_found++;
4060 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4061 struct btrfs_extent_item);
4062 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4063 if (item_size >= sizeof(*ei)) {
4064 flags = btrfs_extent_flags(path->nodes[0], ei);
4065 ret = check_extent_flags(flags);
4067 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4069 btrfs_print_v0_err(trans->fs_info);
4070 btrfs_abort_transaction(trans, err);
4076 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4077 ret = add_tree_block(rc, &key, path, &blocks);
4078 } else if (rc->stage == UPDATE_DATA_PTRS &&
4079 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4080 ret = add_data_references(rc, &key, path, &blocks);
4082 btrfs_release_path(path);
4090 if (!RB_EMPTY_ROOT(&blocks)) {
4091 ret = relocate_tree_blocks(trans, rc, &blocks);
4094 * if we fail to relocate tree blocks, force to update
4095 * backref cache when committing transaction.
4097 rc->backref_cache.last_trans = trans->transid - 1;
4099 if (ret != -EAGAIN) {
4103 rc->extents_found--;
4104 rc->search_start = key.objectid;
4108 btrfs_end_transaction_throttle(trans);
4109 btrfs_btree_balance_dirty(fs_info);
4112 if (rc->stage == MOVE_DATA_EXTENTS &&
4113 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4114 rc->found_file_extent = 1;
4115 ret = relocate_data_extent(rc->data_inode,
4116 &key, &rc->cluster);
4123 if (trans && progress && err == -ENOSPC) {
4124 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4132 btrfs_release_path(path);
4133 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4136 btrfs_end_transaction_throttle(trans);
4137 btrfs_btree_balance_dirty(fs_info);
4141 ret = relocate_file_extent_cluster(rc->data_inode,
4147 rc->create_reloc_tree = 0;
4148 set_reloc_control(rc);
4150 backref_cache_cleanup(&rc->backref_cache);
4151 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4153 err = prepare_to_merge(rc, err);
4155 merge_reloc_roots(rc);
4157 rc->merge_reloc_tree = 0;
4158 unset_reloc_control(rc);
4159 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4161 /* get rid of pinned extents */
4162 trans = btrfs_join_transaction(rc->extent_root);
4163 if (IS_ERR(trans)) {
4164 err = PTR_ERR(trans);
4167 btrfs_commit_transaction(trans);
4168 ret = clean_dirty_subvols(rc);
4169 if (ret < 0 && !err)
4172 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4173 btrfs_free_path(path);
4177 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4178 struct btrfs_root *root, u64 objectid)
4180 struct btrfs_path *path;
4181 struct btrfs_inode_item *item;
4182 struct extent_buffer *leaf;
4185 path = btrfs_alloc_path();
4189 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4193 leaf = path->nodes[0];
4194 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4195 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4196 btrfs_set_inode_generation(leaf, item, 1);
4197 btrfs_set_inode_size(leaf, item, 0);
4198 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4199 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4200 BTRFS_INODE_PREALLOC);
4201 btrfs_mark_buffer_dirty(leaf);
4203 btrfs_free_path(path);
4208 * helper to create inode for data relocation.
4209 * the inode is in data relocation tree and its link count is 0
4211 static noinline_for_stack
4212 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4213 struct btrfs_block_group_cache *group)
4215 struct inode *inode = NULL;
4216 struct btrfs_trans_handle *trans;
4217 struct btrfs_root *root;
4218 struct btrfs_key key;
4222 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4224 return ERR_CAST(root);
4226 trans = btrfs_start_transaction(root, 6);
4228 return ERR_CAST(trans);
4230 err = btrfs_find_free_objectid(root, &objectid);
4234 err = __insert_orphan_inode(trans, root, objectid);
4237 key.objectid = objectid;
4238 key.type = BTRFS_INODE_ITEM_KEY;
4240 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4241 BUG_ON(IS_ERR(inode));
4242 BTRFS_I(inode)->index_cnt = group->key.objectid;
4244 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4246 btrfs_end_transaction(trans);
4247 btrfs_btree_balance_dirty(fs_info);
4251 inode = ERR_PTR(err);
4256 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4258 struct reloc_control *rc;
4260 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4264 INIT_LIST_HEAD(&rc->reloc_roots);
4265 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4266 backref_cache_init(&rc->backref_cache);
4267 mapping_tree_init(&rc->reloc_root_tree);
4268 extent_io_tree_init(fs_info, &rc->processed_blocks,
4269 IO_TREE_RELOC_BLOCKS, NULL);
4274 * Print the block group being relocated
4276 static void describe_relocation(struct btrfs_fs_info *fs_info,
4277 struct btrfs_block_group_cache *block_group)
4279 char buf[128] = {'\0'};
4281 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4284 "relocating block group %llu flags %s",
4285 block_group->key.objectid, buf);
4289 * function to relocate all extents in a block group.
4291 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4293 struct btrfs_block_group_cache *bg;
4294 struct btrfs_root *extent_root = fs_info->extent_root;
4295 struct reloc_control *rc;
4296 struct inode *inode;
4297 struct btrfs_path *path;
4302 bg = btrfs_lookup_block_group(fs_info, group_start);
4306 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4307 btrfs_put_block_group(bg);
4311 rc = alloc_reloc_control(fs_info);
4313 btrfs_put_block_group(bg);
4317 rc->extent_root = extent_root;
4318 rc->block_group = bg;
4320 ret = btrfs_inc_block_group_ro(rc->block_group);
4327 path = btrfs_alloc_path();
4333 inode = lookup_free_space_inode(rc->block_group, path);
4334 btrfs_free_path(path);
4337 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4339 ret = PTR_ERR(inode);
4341 if (ret && ret != -ENOENT) {
4346 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4347 if (IS_ERR(rc->data_inode)) {
4348 err = PTR_ERR(rc->data_inode);
4349 rc->data_inode = NULL;
4353 describe_relocation(fs_info, rc->block_group);
4355 btrfs_wait_block_group_reservations(rc->block_group);
4356 btrfs_wait_nocow_writers(rc->block_group);
4357 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4358 rc->block_group->key.objectid,
4359 rc->block_group->key.offset);
4362 mutex_lock(&fs_info->cleaner_mutex);
4363 ret = relocate_block_group(rc);
4364 mutex_unlock(&fs_info->cleaner_mutex);
4369 * We may have gotten ENOSPC after we already dirtied some
4370 * extents. If writeout happens while we're relocating a
4371 * different block group we could end up hitting the
4372 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4373 * btrfs_reloc_cow_block. Make sure we write everything out
4374 * properly so we don't trip over this problem, and then break
4375 * out of the loop if we hit an error.
4377 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4378 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4382 invalidate_mapping_pages(rc->data_inode->i_mapping,
4384 rc->stage = UPDATE_DATA_PTRS;
4390 if (rc->extents_found == 0)
4393 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4397 WARN_ON(rc->block_group->pinned > 0);
4398 WARN_ON(rc->block_group->reserved > 0);
4399 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4402 btrfs_dec_block_group_ro(rc->block_group);
4403 iput(rc->data_inode);
4404 btrfs_put_block_group(rc->block_group);
4409 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4411 struct btrfs_fs_info *fs_info = root->fs_info;
4412 struct btrfs_trans_handle *trans;
4415 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4417 return PTR_ERR(trans);
4419 memset(&root->root_item.drop_progress, 0,
4420 sizeof(root->root_item.drop_progress));
4421 root->root_item.drop_level = 0;
4422 btrfs_set_root_refs(&root->root_item, 0);
4423 ret = btrfs_update_root(trans, fs_info->tree_root,
4424 &root->root_key, &root->root_item);
4426 err = btrfs_end_transaction(trans);
4433 * recover relocation interrupted by system crash.
4435 * this function resumes merging reloc trees with corresponding fs trees.
4436 * this is important for keeping the sharing of tree blocks
4438 int btrfs_recover_relocation(struct btrfs_root *root)
4440 struct btrfs_fs_info *fs_info = root->fs_info;
4441 LIST_HEAD(reloc_roots);
4442 struct btrfs_key key;
4443 struct btrfs_root *fs_root;
4444 struct btrfs_root *reloc_root;
4445 struct btrfs_path *path;
4446 struct extent_buffer *leaf;
4447 struct reloc_control *rc = NULL;
4448 struct btrfs_trans_handle *trans;
4452 path = btrfs_alloc_path();
4455 path->reada = READA_BACK;
4457 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4458 key.type = BTRFS_ROOT_ITEM_KEY;
4459 key.offset = (u64)-1;
4462 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4469 if (path->slots[0] == 0)
4473 leaf = path->nodes[0];
4474 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4475 btrfs_release_path(path);
4477 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4478 key.type != BTRFS_ROOT_ITEM_KEY)
4481 reloc_root = btrfs_read_fs_root(root, &key);
4482 if (IS_ERR(reloc_root)) {
4483 err = PTR_ERR(reloc_root);
4487 list_add(&reloc_root->root_list, &reloc_roots);
4489 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4490 fs_root = read_fs_root(fs_info,
4491 reloc_root->root_key.offset);
4492 if (IS_ERR(fs_root)) {
4493 ret = PTR_ERR(fs_root);
4494 if (ret != -ENOENT) {
4498 ret = mark_garbage_root(reloc_root);
4506 if (key.offset == 0)
4511 btrfs_release_path(path);
4513 if (list_empty(&reloc_roots))
4516 rc = alloc_reloc_control(fs_info);
4522 rc->extent_root = fs_info->extent_root;
4524 set_reloc_control(rc);
4526 trans = btrfs_join_transaction(rc->extent_root);
4527 if (IS_ERR(trans)) {
4528 unset_reloc_control(rc);
4529 err = PTR_ERR(trans);
4533 rc->merge_reloc_tree = 1;
4535 while (!list_empty(&reloc_roots)) {
4536 reloc_root = list_entry(reloc_roots.next,
4537 struct btrfs_root, root_list);
4538 list_del(&reloc_root->root_list);
4540 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4541 list_add_tail(&reloc_root->root_list,
4546 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4547 if (IS_ERR(fs_root)) {
4548 err = PTR_ERR(fs_root);
4552 err = __add_reloc_root(reloc_root);
4553 BUG_ON(err < 0); /* -ENOMEM or logic error */
4554 fs_root->reloc_root = reloc_root;
4557 err = btrfs_commit_transaction(trans);
4561 merge_reloc_roots(rc);
4563 unset_reloc_control(rc);
4565 trans = btrfs_join_transaction(rc->extent_root);
4566 if (IS_ERR(trans)) {
4567 err = PTR_ERR(trans);
4570 err = btrfs_commit_transaction(trans);
4572 ret = clean_dirty_subvols(rc);
4573 if (ret < 0 && !err)
4578 if (!list_empty(&reloc_roots))
4579 free_reloc_roots(&reloc_roots);
4581 btrfs_free_path(path);
4584 /* cleanup orphan inode in data relocation tree */
4585 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4586 if (IS_ERR(fs_root))
4587 err = PTR_ERR(fs_root);
4589 err = btrfs_orphan_cleanup(fs_root);
4595 * helper to add ordered checksum for data relocation.
4597 * cloning checksum properly handles the nodatasum extents.
4598 * it also saves CPU time to re-calculate the checksum.
4600 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4602 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4603 struct btrfs_ordered_sum *sums;
4604 struct btrfs_ordered_extent *ordered;
4610 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4611 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4613 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4614 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4615 disk_bytenr + len - 1, &list, 0);
4619 while (!list_empty(&list)) {
4620 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4621 list_del_init(&sums->list);
4624 * We need to offset the new_bytenr based on where the csum is.
4625 * We need to do this because we will read in entire prealloc
4626 * extents but we may have written to say the middle of the
4627 * prealloc extent, so we need to make sure the csum goes with
4628 * the right disk offset.
4630 * We can do this because the data reloc inode refers strictly
4631 * to the on disk bytes, so we don't have to worry about
4632 * disk_len vs real len like with real inodes since it's all
4635 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4636 sums->bytenr = new_bytenr;
4638 btrfs_add_ordered_sum(ordered, sums);
4641 btrfs_put_ordered_extent(ordered);
4645 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4646 struct btrfs_root *root, struct extent_buffer *buf,
4647 struct extent_buffer *cow)
4649 struct btrfs_fs_info *fs_info = root->fs_info;
4650 struct reloc_control *rc;
4651 struct backref_node *node;
4656 rc = fs_info->reloc_ctl;
4660 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4661 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4663 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4664 if (buf == root->node)
4665 __update_reloc_root(root, cow->start);
4668 level = btrfs_header_level(buf);
4669 if (btrfs_header_generation(buf) <=
4670 btrfs_root_last_snapshot(&root->root_item))
4673 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4674 rc->create_reloc_tree) {
4675 WARN_ON(!first_cow && level == 0);
4677 node = rc->backref_cache.path[level];
4678 BUG_ON(node->bytenr != buf->start &&
4679 node->new_bytenr != buf->start);
4681 drop_node_buffer(node);
4682 extent_buffer_get(cow);
4684 node->new_bytenr = cow->start;
4686 if (!node->pending) {
4687 list_move_tail(&node->list,
4688 &rc->backref_cache.pending[level]);
4693 __mark_block_processed(rc, node);
4695 if (first_cow && level > 0)
4696 rc->nodes_relocated += buf->len;
4699 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4700 ret = replace_file_extents(trans, rc, root, cow);
4705 * called before creating snapshot. it calculates metadata reservation
4706 * required for relocating tree blocks in the snapshot
4708 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4709 u64 *bytes_to_reserve)
4711 struct btrfs_root *root = pending->root;
4712 struct reloc_control *rc = root->fs_info->reloc_ctl;
4714 if (!root->reloc_root || !rc)
4717 if (!rc->merge_reloc_tree)
4720 root = root->reloc_root;
4721 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4723 * relocation is in the stage of merging trees. the space
4724 * used by merging a reloc tree is twice the size of
4725 * relocated tree nodes in the worst case. half for cowing
4726 * the reloc tree, half for cowing the fs tree. the space
4727 * used by cowing the reloc tree will be freed after the
4728 * tree is dropped. if we create snapshot, cowing the fs
4729 * tree may use more space than it frees. so we need
4730 * reserve extra space.
4732 *bytes_to_reserve += rc->nodes_relocated;
4736 * called after snapshot is created. migrate block reservation
4737 * and create reloc root for the newly created snapshot
4739 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4740 struct btrfs_pending_snapshot *pending)
4742 struct btrfs_root *root = pending->root;
4743 struct btrfs_root *reloc_root;
4744 struct btrfs_root *new_root;
4745 struct reloc_control *rc = root->fs_info->reloc_ctl;
4748 if (!root->reloc_root || !rc)
4751 rc = root->fs_info->reloc_ctl;
4752 rc->merging_rsv_size += rc->nodes_relocated;
4754 if (rc->merge_reloc_tree) {
4755 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4757 rc->nodes_relocated, true);
4762 new_root = pending->snap;
4763 reloc_root = create_reloc_root(trans, root->reloc_root,
4764 new_root->root_key.objectid);
4765 if (IS_ERR(reloc_root))
4766 return PTR_ERR(reloc_root);
4768 ret = __add_reloc_root(reloc_root);
4770 new_root->reloc_root = reloc_root;
4772 if (rc->create_reloc_tree)
4773 ret = clone_backref_node(trans, rc, root, reloc_root);