2 * Copyright (C) 2009 Oracle. All rights reserved.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public
6 * License v2 as published by the Free Software Foundation.
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
11 * General Public License for more details.
13 * You should have received a copy of the GNU General Public
14 * License along with this program; if not, write to the
15 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
16 * Boston, MA 021110-1307, USA.
19 #include <linux/sched.h>
20 #include <linux/pagemap.h>
21 #include <linux/writeback.h>
22 #include <linux/blkdev.h>
23 #include <linux/rbtree.h>
24 #include <linux/slab.h>
27 #include "transaction.h"
30 #include "btrfs_inode.h"
31 #include "async-thread.h"
32 #include "free-space-cache.h"
33 #include "inode-map.h"
35 #include "print-tree.h"
38 * backref_node, mapping_node and tree_block start with this
41 struct rb_node rb_node;
46 * present a tree block in the backref cache
49 struct rb_node rb_node;
53 /* objectid of tree block owner, can be not uptodate */
55 /* link to pending, changed or detached list */
56 struct list_head list;
57 /* list of upper level blocks reference this block */
58 struct list_head upper;
59 /* list of child blocks in the cache */
60 struct list_head lower;
61 /* NULL if this node is not tree root */
62 struct btrfs_root *root;
63 /* extent buffer got by COW the block */
64 struct extent_buffer *eb;
65 /* level of tree block */
67 /* is the block in non-reference counted tree */
68 unsigned int cowonly:1;
69 /* 1 if no child node in the cache */
70 unsigned int lowest:1;
71 /* is the extent buffer locked */
72 unsigned int locked:1;
73 /* has the block been processed */
74 unsigned int processed:1;
75 /* have backrefs of this block been checked */
76 unsigned int checked:1;
78 * 1 if corresponding block has been cowed but some upper
79 * level block pointers may not point to the new location
81 unsigned int pending:1;
83 * 1 if the backref node isn't connected to any other
86 unsigned int detached:1;
90 * present a block pointer in the backref cache
93 struct list_head list[2];
94 struct backref_node *node[2];
99 #define RELOCATION_RESERVED_NODES 256
101 struct backref_cache {
102 /* red black tree of all backref nodes in the cache */
103 struct rb_root rb_root;
104 /* for passing backref nodes to btrfs_reloc_cow_block */
105 struct backref_node *path[BTRFS_MAX_LEVEL];
107 * list of blocks that have been cowed but some block
108 * pointers in upper level blocks may not reflect the
111 struct list_head pending[BTRFS_MAX_LEVEL];
112 /* list of backref nodes with no child node */
113 struct list_head leaves;
114 /* list of blocks that have been cowed in current transaction */
115 struct list_head changed;
116 /* list of detached backref node. */
117 struct list_head detached;
126 * map address of tree root to tree
128 struct mapping_node {
129 struct rb_node rb_node;
134 struct mapping_tree {
135 struct rb_root rb_root;
140 * present a tree block to process
143 struct rb_node rb_node;
145 struct btrfs_key key;
146 unsigned int level:8;
147 unsigned int key_ready:1;
150 #define MAX_EXTENTS 128
152 struct file_extent_cluster {
155 u64 boundary[MAX_EXTENTS];
159 struct reloc_control {
160 /* block group to relocate */
161 struct btrfs_block_group_cache *block_group;
163 struct btrfs_root *extent_root;
164 /* inode for moving data */
165 struct inode *data_inode;
167 struct btrfs_block_rsv *block_rsv;
169 struct backref_cache backref_cache;
171 struct file_extent_cluster cluster;
172 /* tree blocks have been processed */
173 struct extent_io_tree processed_blocks;
174 /* map start of tree root to corresponding reloc tree */
175 struct mapping_tree reloc_root_tree;
176 /* list of reloc trees */
177 struct list_head reloc_roots;
178 /* size of metadata reservation for merging reloc trees */
179 u64 merging_rsv_size;
180 /* size of relocated tree nodes */
182 /* reserved size for block group relocation*/
188 unsigned int stage:8;
189 unsigned int create_reloc_tree:1;
190 unsigned int merge_reloc_tree:1;
191 unsigned int found_file_extent:1;
194 /* stages of data relocation */
195 #define MOVE_DATA_EXTENTS 0
196 #define UPDATE_DATA_PTRS 1
198 static void remove_backref_node(struct backref_cache *cache,
199 struct backref_node *node);
200 static void __mark_block_processed(struct reloc_control *rc,
201 struct backref_node *node);
203 static void mapping_tree_init(struct mapping_tree *tree)
205 tree->rb_root = RB_ROOT;
206 spin_lock_init(&tree->lock);
209 static void backref_cache_init(struct backref_cache *cache)
212 cache->rb_root = RB_ROOT;
213 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
214 INIT_LIST_HEAD(&cache->pending[i]);
215 INIT_LIST_HEAD(&cache->changed);
216 INIT_LIST_HEAD(&cache->detached);
217 INIT_LIST_HEAD(&cache->leaves);
220 static void backref_cache_cleanup(struct backref_cache *cache)
222 struct backref_node *node;
225 while (!list_empty(&cache->detached)) {
226 node = list_entry(cache->detached.next,
227 struct backref_node, list);
228 remove_backref_node(cache, node);
231 while (!list_empty(&cache->leaves)) {
232 node = list_entry(cache->leaves.next,
233 struct backref_node, lower);
234 remove_backref_node(cache, node);
237 cache->last_trans = 0;
239 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
240 ASSERT(list_empty(&cache->pending[i]));
241 ASSERT(list_empty(&cache->changed));
242 ASSERT(list_empty(&cache->detached));
243 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
244 ASSERT(!cache->nr_nodes);
245 ASSERT(!cache->nr_edges);
248 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
250 struct backref_node *node;
252 node = kzalloc(sizeof(*node), GFP_NOFS);
254 INIT_LIST_HEAD(&node->list);
255 INIT_LIST_HEAD(&node->upper);
256 INIT_LIST_HEAD(&node->lower);
257 RB_CLEAR_NODE(&node->rb_node);
263 static void free_backref_node(struct backref_cache *cache,
264 struct backref_node *node)
272 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
274 struct backref_edge *edge;
276 edge = kzalloc(sizeof(*edge), GFP_NOFS);
282 static void free_backref_edge(struct backref_cache *cache,
283 struct backref_edge *edge)
291 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
292 struct rb_node *node)
294 struct rb_node **p = &root->rb_node;
295 struct rb_node *parent = NULL;
296 struct tree_entry *entry;
300 entry = rb_entry(parent, struct tree_entry, rb_node);
302 if (bytenr < entry->bytenr)
304 else if (bytenr > entry->bytenr)
310 rb_link_node(node, parent, p);
311 rb_insert_color(node, root);
315 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
317 struct rb_node *n = root->rb_node;
318 struct tree_entry *entry;
321 entry = rb_entry(n, struct tree_entry, rb_node);
323 if (bytenr < entry->bytenr)
325 else if (bytenr > entry->bytenr)
333 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
336 struct btrfs_fs_info *fs_info = NULL;
337 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
340 fs_info = bnode->root->fs_info;
341 btrfs_panic(fs_info, errno,
342 "Inconsistency in backref cache found at offset %llu",
347 * walk up backref nodes until reach node presents tree root
349 static struct backref_node *walk_up_backref(struct backref_node *node,
350 struct backref_edge *edges[],
353 struct backref_edge *edge;
356 while (!list_empty(&node->upper)) {
357 edge = list_entry(node->upper.next,
358 struct backref_edge, list[LOWER]);
360 node = edge->node[UPPER];
362 BUG_ON(node->detached);
368 * walk down backref nodes to find start of next reference path
370 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
373 struct backref_edge *edge;
374 struct backref_node *lower;
378 edge = edges[idx - 1];
379 lower = edge->node[LOWER];
380 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
384 edge = list_entry(edge->list[LOWER].next,
385 struct backref_edge, list[LOWER]);
386 edges[idx - 1] = edge;
388 return edge->node[UPPER];
394 static void unlock_node_buffer(struct backref_node *node)
397 btrfs_tree_unlock(node->eb);
402 static void drop_node_buffer(struct backref_node *node)
405 unlock_node_buffer(node);
406 free_extent_buffer(node->eb);
411 static void drop_backref_node(struct backref_cache *tree,
412 struct backref_node *node)
414 BUG_ON(!list_empty(&node->upper));
416 drop_node_buffer(node);
417 list_del(&node->list);
418 list_del(&node->lower);
419 if (!RB_EMPTY_NODE(&node->rb_node))
420 rb_erase(&node->rb_node, &tree->rb_root);
421 free_backref_node(tree, node);
425 * remove a backref node from the backref cache
427 static void remove_backref_node(struct backref_cache *cache,
428 struct backref_node *node)
430 struct backref_node *upper;
431 struct backref_edge *edge;
436 BUG_ON(!node->lowest && !node->detached);
437 while (!list_empty(&node->upper)) {
438 edge = list_entry(node->upper.next, struct backref_edge,
440 upper = edge->node[UPPER];
441 list_del(&edge->list[LOWER]);
442 list_del(&edge->list[UPPER]);
443 free_backref_edge(cache, edge);
445 if (RB_EMPTY_NODE(&upper->rb_node)) {
446 BUG_ON(!list_empty(&node->upper));
447 drop_backref_node(cache, node);
453 * add the node to leaf node list if no other
454 * child block cached.
456 if (list_empty(&upper->lower)) {
457 list_add_tail(&upper->lower, &cache->leaves);
462 drop_backref_node(cache, node);
465 static void update_backref_node(struct backref_cache *cache,
466 struct backref_node *node, u64 bytenr)
468 struct rb_node *rb_node;
469 rb_erase(&node->rb_node, &cache->rb_root);
470 node->bytenr = bytenr;
471 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
473 backref_tree_panic(rb_node, -EEXIST, bytenr);
477 * update backref cache after a transaction commit
479 static int update_backref_cache(struct btrfs_trans_handle *trans,
480 struct backref_cache *cache)
482 struct backref_node *node;
485 if (cache->last_trans == 0) {
486 cache->last_trans = trans->transid;
490 if (cache->last_trans == trans->transid)
494 * detached nodes are used to avoid unnecessary backref
495 * lookup. transaction commit changes the extent tree.
496 * so the detached nodes are no longer useful.
498 while (!list_empty(&cache->detached)) {
499 node = list_entry(cache->detached.next,
500 struct backref_node, list);
501 remove_backref_node(cache, node);
504 while (!list_empty(&cache->changed)) {
505 node = list_entry(cache->changed.next,
506 struct backref_node, list);
507 list_del_init(&node->list);
508 BUG_ON(node->pending);
509 update_backref_node(cache, node, node->new_bytenr);
513 * some nodes can be left in the pending list if there were
514 * errors during processing the pending nodes.
516 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
517 list_for_each_entry(node, &cache->pending[level], list) {
518 BUG_ON(!node->pending);
519 if (node->bytenr == node->new_bytenr)
521 update_backref_node(cache, node, node->new_bytenr);
525 cache->last_trans = 0;
530 static int should_ignore_root(struct btrfs_root *root)
532 struct btrfs_root *reloc_root;
534 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
537 reloc_root = root->reloc_root;
541 if (btrfs_header_generation(reloc_root->commit_root) ==
542 root->fs_info->running_transaction->transid)
545 * if there is reloc tree and it was created in previous
546 * transaction backref lookup can find the reloc tree,
547 * so backref node for the fs tree root is useless for
553 * find reloc tree by address of tree root
555 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
558 struct rb_node *rb_node;
559 struct mapping_node *node;
560 struct btrfs_root *root = NULL;
562 spin_lock(&rc->reloc_root_tree.lock);
563 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
565 node = rb_entry(rb_node, struct mapping_node, rb_node);
566 root = (struct btrfs_root *)node->data;
568 spin_unlock(&rc->reloc_root_tree.lock);
572 static int is_cowonly_root(u64 root_objectid)
574 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
575 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
576 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
577 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
578 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
579 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
580 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
581 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
582 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
587 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
590 struct btrfs_key key;
592 key.objectid = root_objectid;
593 key.type = BTRFS_ROOT_ITEM_KEY;
594 if (is_cowonly_root(root_objectid))
597 key.offset = (u64)-1;
599 return btrfs_get_fs_root(fs_info, &key, false);
602 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
603 static noinline_for_stack
604 struct btrfs_root *find_tree_root(struct reloc_control *rc,
605 struct extent_buffer *leaf,
606 struct btrfs_extent_ref_v0 *ref0)
608 struct btrfs_root *root;
609 u64 root_objectid = btrfs_ref_root_v0(leaf, ref0);
610 u64 generation = btrfs_ref_generation_v0(leaf, ref0);
612 BUG_ON(root_objectid == BTRFS_TREE_RELOC_OBJECTID);
614 root = read_fs_root(rc->extent_root->fs_info, root_objectid);
615 BUG_ON(IS_ERR(root));
617 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state) &&
618 generation != btrfs_root_generation(&root->root_item))
625 static noinline_for_stack
626 int find_inline_backref(struct extent_buffer *leaf, int slot,
627 unsigned long *ptr, unsigned long *end)
629 struct btrfs_key key;
630 struct btrfs_extent_item *ei;
631 struct btrfs_tree_block_info *bi;
634 btrfs_item_key_to_cpu(leaf, &key, slot);
636 item_size = btrfs_item_size_nr(leaf, slot);
637 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
638 if (item_size < sizeof(*ei)) {
639 WARN_ON(item_size != sizeof(struct btrfs_extent_item_v0));
643 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
644 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
645 BTRFS_EXTENT_FLAG_TREE_BLOCK));
647 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
648 item_size <= sizeof(*ei) + sizeof(*bi)) {
649 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
652 if (key.type == BTRFS_METADATA_ITEM_KEY &&
653 item_size <= sizeof(*ei)) {
654 WARN_ON(item_size < sizeof(*ei));
658 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
659 bi = (struct btrfs_tree_block_info *)(ei + 1);
660 *ptr = (unsigned long)(bi + 1);
662 *ptr = (unsigned long)(ei + 1);
664 *end = (unsigned long)ei + item_size;
669 * build backref tree for a given tree block. root of the backref tree
670 * corresponds the tree block, leaves of the backref tree correspond
671 * roots of b-trees that reference the tree block.
673 * the basic idea of this function is check backrefs of a given block
674 * to find upper level blocks that reference the block, and then check
675 * backrefs of these upper level blocks recursively. the recursion stop
676 * when tree root is reached or backrefs for the block is cached.
678 * NOTE: if we find backrefs for a block are cached, we know backrefs
679 * for all upper level blocks that directly/indirectly reference the
680 * block are also cached.
682 static noinline_for_stack
683 struct backref_node *build_backref_tree(struct reloc_control *rc,
684 struct btrfs_key *node_key,
685 int level, u64 bytenr)
687 struct backref_cache *cache = &rc->backref_cache;
688 struct btrfs_path *path1;
689 struct btrfs_path *path2;
690 struct extent_buffer *eb;
691 struct btrfs_root *root;
692 struct backref_node *cur;
693 struct backref_node *upper;
694 struct backref_node *lower;
695 struct backref_node *node = NULL;
696 struct backref_node *exist = NULL;
697 struct backref_edge *edge;
698 struct rb_node *rb_node;
699 struct btrfs_key key;
707 bool need_check = true;
709 path1 = btrfs_alloc_path();
710 path2 = btrfs_alloc_path();
711 if (!path1 || !path2) {
715 path1->reada = READA_FORWARD;
716 path2->reada = READA_FORWARD;
718 node = alloc_backref_node(cache);
724 node->bytenr = bytenr;
731 key.objectid = cur->bytenr;
732 key.type = BTRFS_METADATA_ITEM_KEY;
733 key.offset = (u64)-1;
735 path1->search_commit_root = 1;
736 path1->skip_locking = 1;
737 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
744 ASSERT(path1->slots[0]);
748 WARN_ON(cur->checked);
749 if (!list_empty(&cur->upper)) {
751 * the backref was added previously when processing
752 * backref of type BTRFS_TREE_BLOCK_REF_KEY
754 ASSERT(list_is_singular(&cur->upper));
755 edge = list_entry(cur->upper.next, struct backref_edge,
757 ASSERT(list_empty(&edge->list[UPPER]));
758 exist = edge->node[UPPER];
760 * add the upper level block to pending list if we need
764 list_add_tail(&edge->list[UPPER], &list);
771 eb = path1->nodes[0];
774 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
775 ret = btrfs_next_leaf(rc->extent_root, path1);
782 eb = path1->nodes[0];
785 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
786 if (key.objectid != cur->bytenr) {
791 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
792 key.type == BTRFS_METADATA_ITEM_KEY) {
793 ret = find_inline_backref(eb, path1->slots[0],
801 /* update key for inline back ref */
802 struct btrfs_extent_inline_ref *iref;
804 iref = (struct btrfs_extent_inline_ref *)ptr;
805 type = btrfs_get_extent_inline_ref_type(eb, iref,
806 BTRFS_REF_TYPE_BLOCK);
807 if (type == BTRFS_REF_TYPE_INVALID) {
812 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
814 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
815 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
819 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
820 exist->owner == key.offset) ||
821 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
822 exist->bytenr == key.offset))) {
827 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
828 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY ||
829 key.type == BTRFS_EXTENT_REF_V0_KEY) {
830 if (key.type == BTRFS_EXTENT_REF_V0_KEY) {
831 struct btrfs_extent_ref_v0 *ref0;
832 ref0 = btrfs_item_ptr(eb, path1->slots[0],
833 struct btrfs_extent_ref_v0);
834 if (key.objectid == key.offset) {
835 root = find_tree_root(rc, eb, ref0);
836 if (root && !should_ignore_root(root))
839 list_add(&cur->list, &useless);
842 if (is_cowonly_root(btrfs_ref_root_v0(eb,
847 ASSERT(key.type != BTRFS_EXTENT_REF_V0_KEY);
848 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
850 if (key.objectid == key.offset) {
852 * only root blocks of reloc trees use
853 * backref of this type.
855 root = find_reloc_root(rc, cur->bytenr);
861 edge = alloc_backref_edge(cache);
866 rb_node = tree_search(&cache->rb_root, key.offset);
868 upper = alloc_backref_node(cache);
870 free_backref_edge(cache, edge);
874 upper->bytenr = key.offset;
875 upper->level = cur->level + 1;
877 * backrefs for the upper level block isn't
878 * cached, add the block to pending list
880 list_add_tail(&edge->list[UPPER], &list);
882 upper = rb_entry(rb_node, struct backref_node,
884 ASSERT(upper->checked);
885 INIT_LIST_HEAD(&edge->list[UPPER]);
887 list_add_tail(&edge->list[LOWER], &cur->upper);
888 edge->node[LOWER] = cur;
889 edge->node[UPPER] = upper;
892 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
896 /* key.type == BTRFS_TREE_BLOCK_REF_KEY */
897 root = read_fs_root(rc->extent_root->fs_info, key.offset);
903 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
906 if (btrfs_root_level(&root->root_item) == cur->level) {
908 ASSERT(btrfs_root_bytenr(&root->root_item) ==
910 if (should_ignore_root(root))
911 list_add(&cur->list, &useless);
917 level = cur->level + 1;
920 * searching the tree to find upper level blocks
921 * reference the block.
923 path2->search_commit_root = 1;
924 path2->skip_locking = 1;
925 path2->lowest_level = level;
926 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
927 path2->lowest_level = 0;
932 if (ret > 0 && path2->slots[level] > 0)
933 path2->slots[level]--;
935 eb = path2->nodes[level];
936 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
938 btrfs_err(root->fs_info,
939 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
940 cur->bytenr, level - 1, root->objectid,
941 node_key->objectid, node_key->type,
948 for (; level < BTRFS_MAX_LEVEL; level++) {
949 if (!path2->nodes[level]) {
950 ASSERT(btrfs_root_bytenr(&root->root_item) ==
952 if (should_ignore_root(root))
953 list_add(&lower->list, &useless);
959 edge = alloc_backref_edge(cache);
965 eb = path2->nodes[level];
966 rb_node = tree_search(&cache->rb_root, eb->start);
968 upper = alloc_backref_node(cache);
970 free_backref_edge(cache, edge);
974 upper->bytenr = eb->start;
975 upper->owner = btrfs_header_owner(eb);
976 upper->level = lower->level + 1;
977 if (!test_bit(BTRFS_ROOT_REF_COWS,
982 * if we know the block isn't shared
983 * we can void checking its backrefs.
985 if (btrfs_block_can_be_shared(root, eb))
991 * add the block to pending list if we
992 * need check its backrefs, we only do this once
993 * while walking up a tree as we will catch
994 * anything else later on.
996 if (!upper->checked && need_check) {
998 list_add_tail(&edge->list[UPPER],
1003 INIT_LIST_HEAD(&edge->list[UPPER]);
1006 upper = rb_entry(rb_node, struct backref_node,
1008 ASSERT(upper->checked);
1009 INIT_LIST_HEAD(&edge->list[UPPER]);
1011 upper->owner = btrfs_header_owner(eb);
1013 list_add_tail(&edge->list[LOWER], &lower->upper);
1014 edge->node[LOWER] = lower;
1015 edge->node[UPPER] = upper;
1022 btrfs_release_path(path2);
1025 ptr += btrfs_extent_inline_ref_size(key.type);
1035 btrfs_release_path(path1);
1040 /* the pending list isn't empty, take the first block to process */
1041 if (!list_empty(&list)) {
1042 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1043 list_del_init(&edge->list[UPPER]);
1044 cur = edge->node[UPPER];
1049 * everything goes well, connect backref nodes and insert backref nodes
1052 ASSERT(node->checked);
1053 cowonly = node->cowonly;
1055 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1058 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1059 list_add_tail(&node->lower, &cache->leaves);
1062 list_for_each_entry(edge, &node->upper, list[LOWER])
1063 list_add_tail(&edge->list[UPPER], &list);
1065 while (!list_empty(&list)) {
1066 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1067 list_del_init(&edge->list[UPPER]);
1068 upper = edge->node[UPPER];
1069 if (upper->detached) {
1070 list_del(&edge->list[LOWER]);
1071 lower = edge->node[LOWER];
1072 free_backref_edge(cache, edge);
1073 if (list_empty(&lower->upper))
1074 list_add(&lower->list, &useless);
1078 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1079 if (upper->lowest) {
1080 list_del_init(&upper->lower);
1084 list_add_tail(&edge->list[UPPER], &upper->lower);
1088 if (!upper->checked) {
1090 * Still want to blow up for developers since this is a
1097 if (cowonly != upper->cowonly) {
1104 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1107 backref_tree_panic(rb_node, -EEXIST,
1111 list_add_tail(&edge->list[UPPER], &upper->lower);
1113 list_for_each_entry(edge, &upper->upper, list[LOWER])
1114 list_add_tail(&edge->list[UPPER], &list);
1117 * process useless backref nodes. backref nodes for tree leaves
1118 * are deleted from the cache. backref nodes for upper level
1119 * tree blocks are left in the cache to avoid unnecessary backref
1122 while (!list_empty(&useless)) {
1123 upper = list_entry(useless.next, struct backref_node, list);
1124 list_del_init(&upper->list);
1125 ASSERT(list_empty(&upper->upper));
1128 if (upper->lowest) {
1129 list_del_init(&upper->lower);
1132 while (!list_empty(&upper->lower)) {
1133 edge = list_entry(upper->lower.next,
1134 struct backref_edge, list[UPPER]);
1135 list_del(&edge->list[UPPER]);
1136 list_del(&edge->list[LOWER]);
1137 lower = edge->node[LOWER];
1138 free_backref_edge(cache, edge);
1140 if (list_empty(&lower->upper))
1141 list_add(&lower->list, &useless);
1143 __mark_block_processed(rc, upper);
1144 if (upper->level > 0) {
1145 list_add(&upper->list, &cache->detached);
1146 upper->detached = 1;
1148 rb_erase(&upper->rb_node, &cache->rb_root);
1149 free_backref_node(cache, upper);
1153 btrfs_free_path(path1);
1154 btrfs_free_path(path2);
1156 while (!list_empty(&useless)) {
1157 lower = list_entry(useless.next,
1158 struct backref_node, list);
1159 list_del_init(&lower->list);
1161 while (!list_empty(&list)) {
1162 edge = list_first_entry(&list, struct backref_edge,
1164 list_del(&edge->list[UPPER]);
1165 list_del(&edge->list[LOWER]);
1166 lower = edge->node[LOWER];
1167 upper = edge->node[UPPER];
1168 free_backref_edge(cache, edge);
1171 * Lower is no longer linked to any upper backref nodes
1172 * and isn't in the cache, we can free it ourselves.
1174 if (list_empty(&lower->upper) &&
1175 RB_EMPTY_NODE(&lower->rb_node))
1176 list_add(&lower->list, &useless);
1178 if (!RB_EMPTY_NODE(&upper->rb_node))
1181 /* Add this guy's upper edges to the list to process */
1182 list_for_each_entry(edge, &upper->upper, list[LOWER])
1183 list_add_tail(&edge->list[UPPER], &list);
1184 if (list_empty(&upper->upper))
1185 list_add(&upper->list, &useless);
1188 while (!list_empty(&useless)) {
1189 lower = list_entry(useless.next,
1190 struct backref_node, list);
1191 list_del_init(&lower->list);
1194 free_backref_node(cache, lower);
1197 remove_backref_node(cache, node);
1198 return ERR_PTR(err);
1200 ASSERT(!node || !node->detached);
1205 * helper to add backref node for the newly created snapshot.
1206 * the backref node is created by cloning backref node that
1207 * corresponds to root of source tree
1209 static int clone_backref_node(struct btrfs_trans_handle *trans,
1210 struct reloc_control *rc,
1211 struct btrfs_root *src,
1212 struct btrfs_root *dest)
1214 struct btrfs_root *reloc_root = src->reloc_root;
1215 struct backref_cache *cache = &rc->backref_cache;
1216 struct backref_node *node = NULL;
1217 struct backref_node *new_node;
1218 struct backref_edge *edge;
1219 struct backref_edge *new_edge;
1220 struct rb_node *rb_node;
1222 if (cache->last_trans > 0)
1223 update_backref_cache(trans, cache);
1225 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1227 node = rb_entry(rb_node, struct backref_node, rb_node);
1231 BUG_ON(node->new_bytenr != reloc_root->node->start);
1235 rb_node = tree_search(&cache->rb_root,
1236 reloc_root->commit_root->start);
1238 node = rb_entry(rb_node, struct backref_node,
1240 BUG_ON(node->detached);
1247 new_node = alloc_backref_node(cache);
1251 new_node->bytenr = dest->node->start;
1252 new_node->level = node->level;
1253 new_node->lowest = node->lowest;
1254 new_node->checked = 1;
1255 new_node->root = dest;
1257 if (!node->lowest) {
1258 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1259 new_edge = alloc_backref_edge(cache);
1263 new_edge->node[UPPER] = new_node;
1264 new_edge->node[LOWER] = edge->node[LOWER];
1265 list_add_tail(&new_edge->list[UPPER],
1269 list_add_tail(&new_node->lower, &cache->leaves);
1272 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1273 &new_node->rb_node);
1275 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1277 if (!new_node->lowest) {
1278 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1279 list_add_tail(&new_edge->list[LOWER],
1280 &new_edge->node[LOWER]->upper);
1285 while (!list_empty(&new_node->lower)) {
1286 new_edge = list_entry(new_node->lower.next,
1287 struct backref_edge, list[UPPER]);
1288 list_del(&new_edge->list[UPPER]);
1289 free_backref_edge(cache, new_edge);
1291 free_backref_node(cache, new_node);
1296 * helper to add 'address of tree root -> reloc tree' mapping
1298 static int __must_check __add_reloc_root(struct btrfs_root *root)
1300 struct btrfs_fs_info *fs_info = root->fs_info;
1301 struct rb_node *rb_node;
1302 struct mapping_node *node;
1303 struct reloc_control *rc = fs_info->reloc_ctl;
1305 node = kmalloc(sizeof(*node), GFP_NOFS);
1309 node->bytenr = root->commit_root->start;
1312 spin_lock(&rc->reloc_root_tree.lock);
1313 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1314 node->bytenr, &node->rb_node);
1315 spin_unlock(&rc->reloc_root_tree.lock);
1317 btrfs_panic(fs_info, -EEXIST,
1318 "Duplicate root found for start=%llu while inserting into relocation tree",
1322 list_add_tail(&root->root_list, &rc->reloc_roots);
1327 * helper to delete the 'address of tree root -> reloc tree'
1330 static void __del_reloc_root(struct btrfs_root *root)
1332 struct btrfs_fs_info *fs_info = root->fs_info;
1333 struct rb_node *rb_node;
1334 struct mapping_node *node = NULL;
1335 struct reloc_control *rc = fs_info->reloc_ctl;
1337 if (rc && root->node) {
1338 spin_lock(&rc->reloc_root_tree.lock);
1339 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1340 root->commit_root->start);
1342 node = rb_entry(rb_node, struct mapping_node, rb_node);
1343 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1344 RB_CLEAR_NODE(&node->rb_node);
1346 spin_unlock(&rc->reloc_root_tree.lock);
1347 ASSERT(!node || (struct btrfs_root *)node->data == root);
1350 spin_lock(&fs_info->trans_lock);
1351 list_del_init(&root->root_list);
1352 spin_unlock(&fs_info->trans_lock);
1357 * helper to update the 'address of tree root -> reloc tree'
1360 static int __update_reloc_root(struct btrfs_root *root)
1362 struct btrfs_fs_info *fs_info = root->fs_info;
1363 struct rb_node *rb_node;
1364 struct mapping_node *node = NULL;
1365 struct reloc_control *rc = fs_info->reloc_ctl;
1367 spin_lock(&rc->reloc_root_tree.lock);
1368 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1369 root->commit_root->start);
1371 node = rb_entry(rb_node, struct mapping_node, rb_node);
1372 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1374 spin_unlock(&rc->reloc_root_tree.lock);
1378 BUG_ON((struct btrfs_root *)node->data != root);
1380 spin_lock(&rc->reloc_root_tree.lock);
1381 node->bytenr = root->node->start;
1382 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1383 node->bytenr, &node->rb_node);
1384 spin_unlock(&rc->reloc_root_tree.lock);
1386 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1390 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1391 struct btrfs_root *root, u64 objectid)
1393 struct btrfs_fs_info *fs_info = root->fs_info;
1394 struct btrfs_root *reloc_root;
1395 struct extent_buffer *eb;
1396 struct btrfs_root_item *root_item;
1397 struct btrfs_key root_key;
1400 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1403 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1404 root_key.type = BTRFS_ROOT_ITEM_KEY;
1405 root_key.offset = objectid;
1407 if (root->root_key.objectid == objectid) {
1408 u64 commit_root_gen;
1410 /* called by btrfs_init_reloc_root */
1411 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1412 BTRFS_TREE_RELOC_OBJECTID);
1415 * Set the last_snapshot field to the generation of the commit
1416 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1417 * correctly (returns true) when the relocation root is created
1418 * either inside the critical section of a transaction commit
1419 * (through transaction.c:qgroup_account_snapshot()) and when
1420 * it's created before the transaction commit is started.
1422 commit_root_gen = btrfs_header_generation(root->commit_root);
1423 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1426 * called by btrfs_reloc_post_snapshot_hook.
1427 * the source tree is a reloc tree, all tree blocks
1428 * modified after it was created have RELOC flag
1429 * set in their headers. so it's OK to not update
1430 * the 'last_snapshot'.
1432 ret = btrfs_copy_root(trans, root, root->node, &eb,
1433 BTRFS_TREE_RELOC_OBJECTID);
1437 memcpy(root_item, &root->root_item, sizeof(*root_item));
1438 btrfs_set_root_bytenr(root_item, eb->start);
1439 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1440 btrfs_set_root_generation(root_item, trans->transid);
1442 if (root->root_key.objectid == objectid) {
1443 btrfs_set_root_refs(root_item, 0);
1444 memset(&root_item->drop_progress, 0,
1445 sizeof(struct btrfs_disk_key));
1446 root_item->drop_level = 0;
1449 btrfs_tree_unlock(eb);
1450 free_extent_buffer(eb);
1452 ret = btrfs_insert_root(trans, fs_info->tree_root,
1453 &root_key, root_item);
1457 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1458 BUG_ON(IS_ERR(reloc_root));
1459 reloc_root->last_trans = trans->transid;
1464 * create reloc tree for a given fs tree. reloc tree is just a
1465 * snapshot of the fs tree with special root objectid.
1467 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1468 struct btrfs_root *root)
1470 struct btrfs_fs_info *fs_info = root->fs_info;
1471 struct btrfs_root *reloc_root;
1472 struct reloc_control *rc = fs_info->reloc_ctl;
1473 struct btrfs_block_rsv *rsv;
1477 if (root->reloc_root) {
1478 reloc_root = root->reloc_root;
1479 reloc_root->last_trans = trans->transid;
1483 if (!rc || !rc->create_reloc_tree ||
1484 root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1487 if (!trans->reloc_reserved) {
1488 rsv = trans->block_rsv;
1489 trans->block_rsv = rc->block_rsv;
1492 reloc_root = create_reloc_root(trans, root, root->root_key.objectid);
1494 trans->block_rsv = rsv;
1496 ret = __add_reloc_root(reloc_root);
1498 root->reloc_root = reloc_root;
1503 * update root item of reloc tree
1505 int btrfs_update_reloc_root(struct btrfs_trans_handle *trans,
1506 struct btrfs_root *root)
1508 struct btrfs_fs_info *fs_info = root->fs_info;
1509 struct btrfs_root *reloc_root;
1510 struct btrfs_root_item *root_item;
1513 if (!root->reloc_root)
1516 reloc_root = root->reloc_root;
1517 root_item = &reloc_root->root_item;
1519 if (fs_info->reloc_ctl->merge_reloc_tree &&
1520 btrfs_root_refs(root_item) == 0) {
1521 root->reloc_root = NULL;
1522 __del_reloc_root(reloc_root);
1525 if (reloc_root->commit_root != reloc_root->node) {
1526 __update_reloc_root(reloc_root);
1527 btrfs_set_root_node(root_item, reloc_root->node);
1528 free_extent_buffer(reloc_root->commit_root);
1529 reloc_root->commit_root = btrfs_root_node(reloc_root);
1532 ret = btrfs_update_root(trans, fs_info->tree_root,
1533 &reloc_root->root_key, root_item);
1541 * helper to find first cached inode with inode number >= objectid
1544 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1546 struct rb_node *node;
1547 struct rb_node *prev;
1548 struct btrfs_inode *entry;
1549 struct inode *inode;
1551 spin_lock(&root->inode_lock);
1553 node = root->inode_tree.rb_node;
1557 entry = rb_entry(node, struct btrfs_inode, rb_node);
1559 if (objectid < btrfs_ino(entry))
1560 node = node->rb_left;
1561 else if (objectid > btrfs_ino(entry))
1562 node = node->rb_right;
1568 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1569 if (objectid <= btrfs_ino(entry)) {
1573 prev = rb_next(prev);
1577 entry = rb_entry(node, struct btrfs_inode, rb_node);
1578 inode = igrab(&entry->vfs_inode);
1580 spin_unlock(&root->inode_lock);
1584 objectid = btrfs_ino(entry) + 1;
1585 if (cond_resched_lock(&root->inode_lock))
1588 node = rb_next(node);
1590 spin_unlock(&root->inode_lock);
1594 static int in_block_group(u64 bytenr,
1595 struct btrfs_block_group_cache *block_group)
1597 if (bytenr >= block_group->key.objectid &&
1598 bytenr < block_group->key.objectid + block_group->key.offset)
1604 * get new location of data
1606 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1607 u64 bytenr, u64 num_bytes)
1609 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1610 struct btrfs_path *path;
1611 struct btrfs_file_extent_item *fi;
1612 struct extent_buffer *leaf;
1615 path = btrfs_alloc_path();
1619 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1620 ret = btrfs_lookup_file_extent(NULL, root, path,
1621 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1629 leaf = path->nodes[0];
1630 fi = btrfs_item_ptr(leaf, path->slots[0],
1631 struct btrfs_file_extent_item);
1633 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1634 btrfs_file_extent_compression(leaf, fi) ||
1635 btrfs_file_extent_encryption(leaf, fi) ||
1636 btrfs_file_extent_other_encoding(leaf, fi));
1638 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1643 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1646 btrfs_free_path(path);
1651 * update file extent items in the tree leaf to point to
1652 * the new locations.
1654 static noinline_for_stack
1655 int replace_file_extents(struct btrfs_trans_handle *trans,
1656 struct reloc_control *rc,
1657 struct btrfs_root *root,
1658 struct extent_buffer *leaf)
1660 struct btrfs_fs_info *fs_info = root->fs_info;
1661 struct btrfs_key key;
1662 struct btrfs_file_extent_item *fi;
1663 struct inode *inode = NULL;
1675 if (rc->stage != UPDATE_DATA_PTRS)
1678 /* reloc trees always use full backref */
1679 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1680 parent = leaf->start;
1684 nritems = btrfs_header_nritems(leaf);
1685 for (i = 0; i < nritems; i++) {
1687 btrfs_item_key_to_cpu(leaf, &key, i);
1688 if (key.type != BTRFS_EXTENT_DATA_KEY)
1690 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1691 if (btrfs_file_extent_type(leaf, fi) ==
1692 BTRFS_FILE_EXTENT_INLINE)
1694 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1695 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1698 if (!in_block_group(bytenr, rc->block_group))
1702 * if we are modifying block in fs tree, wait for readpage
1703 * to complete and drop the extent cache
1705 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1707 inode = find_next_inode(root, key.objectid);
1709 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1710 btrfs_add_delayed_iput(inode);
1711 inode = find_next_inode(root, key.objectid);
1713 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1715 btrfs_file_extent_num_bytes(leaf, fi);
1716 WARN_ON(!IS_ALIGNED(key.offset,
1717 fs_info->sectorsize));
1718 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1720 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1725 btrfs_drop_extent_cache(BTRFS_I(inode),
1726 key.offset, end, 1);
1727 unlock_extent(&BTRFS_I(inode)->io_tree,
1732 ret = get_new_location(rc->data_inode, &new_bytenr,
1736 * Don't have to abort since we've not changed anything
1737 * in the file extent yet.
1742 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1745 key.offset -= btrfs_file_extent_offset(leaf, fi);
1746 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1748 btrfs_header_owner(leaf),
1749 key.objectid, key.offset);
1751 btrfs_abort_transaction(trans, ret);
1755 ret = btrfs_free_extent(trans, fs_info, bytenr, num_bytes,
1756 parent, btrfs_header_owner(leaf),
1757 key.objectid, key.offset);
1759 btrfs_abort_transaction(trans, ret);
1764 btrfs_mark_buffer_dirty(leaf);
1766 btrfs_add_delayed_iput(inode);
1770 static noinline_for_stack
1771 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1772 struct btrfs_path *path, int level)
1774 struct btrfs_disk_key key1;
1775 struct btrfs_disk_key key2;
1776 btrfs_node_key(eb, &key1, slot);
1777 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1778 return memcmp(&key1, &key2, sizeof(key1));
1782 * try to replace tree blocks in fs tree with the new blocks
1783 * in reloc tree. tree blocks haven't been modified since the
1784 * reloc tree was create can be replaced.
1786 * if a block was replaced, level of the block + 1 is returned.
1787 * if no block got replaced, 0 is returned. if there are other
1788 * errors, a negative error number is returned.
1790 static noinline_for_stack
1791 int replace_path(struct btrfs_trans_handle *trans,
1792 struct btrfs_root *dest, struct btrfs_root *src,
1793 struct btrfs_path *path, struct btrfs_key *next_key,
1794 int lowest_level, int max_level)
1796 struct btrfs_fs_info *fs_info = dest->fs_info;
1797 struct extent_buffer *eb;
1798 struct extent_buffer *parent;
1799 struct btrfs_key key;
1811 ASSERT(src->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1812 ASSERT(dest->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1814 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1816 slot = path->slots[lowest_level];
1817 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1819 eb = btrfs_lock_root_node(dest);
1820 btrfs_set_lock_blocking(eb);
1821 level = btrfs_header_level(eb);
1823 if (level < lowest_level) {
1824 btrfs_tree_unlock(eb);
1825 free_extent_buffer(eb);
1830 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1833 btrfs_set_lock_blocking(eb);
1836 next_key->objectid = (u64)-1;
1837 next_key->type = (u8)-1;
1838 next_key->offset = (u64)-1;
1843 level = btrfs_header_level(parent);
1844 ASSERT(level >= lowest_level);
1846 ret = btrfs_bin_search(parent, &key, level, &slot);
1847 if (ret && slot > 0)
1850 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1851 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1853 old_bytenr = btrfs_node_blockptr(parent, slot);
1854 blocksize = fs_info->nodesize;
1855 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1857 if (level <= max_level) {
1858 eb = path->nodes[level];
1859 new_bytenr = btrfs_node_blockptr(eb,
1860 path->slots[level]);
1861 new_ptr_gen = btrfs_node_ptr_generation(eb,
1862 path->slots[level]);
1868 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1873 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1874 memcmp_node_keys(parent, slot, path, level)) {
1875 if (level <= lowest_level) {
1880 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen);
1884 } else if (!extent_buffer_uptodate(eb)) {
1886 free_extent_buffer(eb);
1889 btrfs_tree_lock(eb);
1891 ret = btrfs_cow_block(trans, dest, eb, parent,
1895 btrfs_set_lock_blocking(eb);
1897 btrfs_tree_unlock(parent);
1898 free_extent_buffer(parent);
1905 btrfs_tree_unlock(parent);
1906 free_extent_buffer(parent);
1911 btrfs_node_key_to_cpu(path->nodes[level], &key,
1912 path->slots[level]);
1913 btrfs_release_path(path);
1915 path->lowest_level = level;
1916 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1917 path->lowest_level = 0;
1921 * Info qgroup to trace both subtrees.
1923 * We must trace both trees.
1924 * 1) Tree reloc subtree
1925 * If not traced, we will leak data numbers
1927 * If not traced, we will double count old data
1928 * and tree block numbers, if current trans doesn't free
1929 * data reloc tree inode.
1931 ret = btrfs_qgroup_trace_subtree(trans, src, parent,
1932 btrfs_header_generation(parent),
1933 btrfs_header_level(parent));
1936 ret = btrfs_qgroup_trace_subtree(trans, dest,
1938 btrfs_header_generation(path->nodes[level]),
1939 btrfs_header_level(path->nodes[level]));
1944 * swap blocks in fs tree and reloc tree.
1946 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1947 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1948 btrfs_mark_buffer_dirty(parent);
1950 btrfs_set_node_blockptr(path->nodes[level],
1951 path->slots[level], old_bytenr);
1952 btrfs_set_node_ptr_generation(path->nodes[level],
1953 path->slots[level], old_ptr_gen);
1954 btrfs_mark_buffer_dirty(path->nodes[level]);
1956 ret = btrfs_inc_extent_ref(trans, fs_info, old_bytenr,
1957 blocksize, path->nodes[level]->start,
1958 src->root_key.objectid, level - 1, 0);
1960 ret = btrfs_inc_extent_ref(trans, fs_info, new_bytenr,
1961 blocksize, 0, dest->root_key.objectid,
1965 ret = btrfs_free_extent(trans, fs_info, new_bytenr, blocksize,
1966 path->nodes[level]->start,
1967 src->root_key.objectid, level - 1, 0);
1970 ret = btrfs_free_extent(trans, fs_info, old_bytenr, blocksize,
1971 0, dest->root_key.objectid, level - 1,
1975 btrfs_unlock_up_safe(path, 0);
1980 btrfs_tree_unlock(parent);
1981 free_extent_buffer(parent);
1986 * helper to find next relocated block in reloc tree
1988 static noinline_for_stack
1989 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
1992 struct extent_buffer *eb;
1997 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
1999 for (i = 0; i < *level; i++) {
2000 free_extent_buffer(path->nodes[i]);
2001 path->nodes[i] = NULL;
2004 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
2005 eb = path->nodes[i];
2006 nritems = btrfs_header_nritems(eb);
2007 while (path->slots[i] + 1 < nritems) {
2009 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2016 free_extent_buffer(path->nodes[i]);
2017 path->nodes[i] = NULL;
2023 * walk down reloc tree to find relocated block of lowest level
2025 static noinline_for_stack
2026 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2029 struct btrfs_fs_info *fs_info = root->fs_info;
2030 struct extent_buffer *eb = NULL;
2037 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2039 for (i = *level; i > 0; i--) {
2040 eb = path->nodes[i];
2041 nritems = btrfs_header_nritems(eb);
2042 while (path->slots[i] < nritems) {
2043 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2044 if (ptr_gen > last_snapshot)
2048 if (path->slots[i] >= nritems) {
2059 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2060 eb = read_tree_block(fs_info, bytenr, ptr_gen);
2063 } else if (!extent_buffer_uptodate(eb)) {
2064 free_extent_buffer(eb);
2067 BUG_ON(btrfs_header_level(eb) != i - 1);
2068 path->nodes[i - 1] = eb;
2069 path->slots[i - 1] = 0;
2075 * invalidate extent cache for file extents whose key in range of
2076 * [min_key, max_key)
2078 static int invalidate_extent_cache(struct btrfs_root *root,
2079 struct btrfs_key *min_key,
2080 struct btrfs_key *max_key)
2082 struct btrfs_fs_info *fs_info = root->fs_info;
2083 struct inode *inode = NULL;
2088 objectid = min_key->objectid;
2093 if (objectid > max_key->objectid)
2096 inode = find_next_inode(root, objectid);
2099 ino = btrfs_ino(BTRFS_I(inode));
2101 if (ino > max_key->objectid) {
2107 if (!S_ISREG(inode->i_mode))
2110 if (unlikely(min_key->objectid == ino)) {
2111 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2113 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2116 start = min_key->offset;
2117 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2123 if (unlikely(max_key->objectid == ino)) {
2124 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2126 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2129 if (max_key->offset == 0)
2131 end = max_key->offset;
2132 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2139 /* the lock_extent waits for readpage to complete */
2140 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2141 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2142 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2147 static int find_next_key(struct btrfs_path *path, int level,
2148 struct btrfs_key *key)
2151 while (level < BTRFS_MAX_LEVEL) {
2152 if (!path->nodes[level])
2154 if (path->slots[level] + 1 <
2155 btrfs_header_nritems(path->nodes[level])) {
2156 btrfs_node_key_to_cpu(path->nodes[level], key,
2157 path->slots[level] + 1);
2166 * merge the relocated tree blocks in reloc tree with corresponding
2169 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2170 struct btrfs_root *root)
2172 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2173 LIST_HEAD(inode_list);
2174 struct btrfs_key key;
2175 struct btrfs_key next_key;
2176 struct btrfs_trans_handle *trans = NULL;
2177 struct btrfs_root *reloc_root;
2178 struct btrfs_root_item *root_item;
2179 struct btrfs_path *path;
2180 struct extent_buffer *leaf;
2188 path = btrfs_alloc_path();
2191 path->reada = READA_FORWARD;
2193 reloc_root = root->reloc_root;
2194 root_item = &reloc_root->root_item;
2196 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2197 level = btrfs_root_level(root_item);
2198 extent_buffer_get(reloc_root->node);
2199 path->nodes[level] = reloc_root->node;
2200 path->slots[level] = 0;
2202 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2204 level = root_item->drop_level;
2206 path->lowest_level = level;
2207 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2208 path->lowest_level = 0;
2210 btrfs_free_path(path);
2214 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2215 path->slots[level]);
2216 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2218 btrfs_unlock_up_safe(path, 0);
2221 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2222 memset(&next_key, 0, sizeof(next_key));
2225 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2226 BTRFS_RESERVE_FLUSH_ALL);
2231 trans = btrfs_start_transaction(root, 0);
2232 if (IS_ERR(trans)) {
2233 err = PTR_ERR(trans);
2237 trans->block_rsv = rc->block_rsv;
2242 ret = walk_down_reloc_tree(reloc_root, path, &level);
2250 if (!find_next_key(path, level, &key) &&
2251 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2254 ret = replace_path(trans, root, reloc_root, path,
2255 &next_key, level, max_level);
2264 btrfs_node_key_to_cpu(path->nodes[level], &key,
2265 path->slots[level]);
2269 ret = walk_up_reloc_tree(reloc_root, path, &level);
2275 * save the merging progress in the drop_progress.
2276 * this is OK since root refs == 1 in this case.
2278 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2279 path->slots[level]);
2280 root_item->drop_level = level;
2282 btrfs_end_transaction_throttle(trans);
2285 btrfs_btree_balance_dirty(fs_info);
2287 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2288 invalidate_extent_cache(root, &key, &next_key);
2292 * handle the case only one block in the fs tree need to be
2293 * relocated and the block is tree root.
2295 leaf = btrfs_lock_root_node(root);
2296 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2297 btrfs_tree_unlock(leaf);
2298 free_extent_buffer(leaf);
2302 btrfs_free_path(path);
2305 memset(&root_item->drop_progress, 0,
2306 sizeof(root_item->drop_progress));
2307 root_item->drop_level = 0;
2308 btrfs_set_root_refs(root_item, 0);
2309 btrfs_update_reloc_root(trans, root);
2313 btrfs_end_transaction_throttle(trans);
2315 btrfs_btree_balance_dirty(fs_info);
2317 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2318 invalidate_extent_cache(root, &key, &next_key);
2323 static noinline_for_stack
2324 int prepare_to_merge(struct reloc_control *rc, int err)
2326 struct btrfs_root *root = rc->extent_root;
2327 struct btrfs_fs_info *fs_info = root->fs_info;
2328 struct btrfs_root *reloc_root;
2329 struct btrfs_trans_handle *trans;
2330 LIST_HEAD(reloc_roots);
2334 mutex_lock(&fs_info->reloc_mutex);
2335 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2336 rc->merging_rsv_size += rc->nodes_relocated * 2;
2337 mutex_unlock(&fs_info->reloc_mutex);
2341 num_bytes = rc->merging_rsv_size;
2342 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2343 BTRFS_RESERVE_FLUSH_ALL);
2348 trans = btrfs_join_transaction(rc->extent_root);
2349 if (IS_ERR(trans)) {
2351 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2353 return PTR_ERR(trans);
2357 if (num_bytes != rc->merging_rsv_size) {
2358 btrfs_end_transaction(trans);
2359 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2365 rc->merge_reloc_tree = 1;
2367 while (!list_empty(&rc->reloc_roots)) {
2368 reloc_root = list_entry(rc->reloc_roots.next,
2369 struct btrfs_root, root_list);
2370 list_del_init(&reloc_root->root_list);
2372 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2373 BUG_ON(IS_ERR(root));
2374 BUG_ON(root->reloc_root != reloc_root);
2377 * set reference count to 1, so btrfs_recover_relocation
2378 * knows it should resumes merging
2381 btrfs_set_root_refs(&reloc_root->root_item, 1);
2382 btrfs_update_reloc_root(trans, root);
2384 list_add(&reloc_root->root_list, &reloc_roots);
2387 list_splice(&reloc_roots, &rc->reloc_roots);
2390 btrfs_commit_transaction(trans);
2392 btrfs_end_transaction(trans);
2396 static noinline_for_stack
2397 void free_reloc_roots(struct list_head *list)
2399 struct btrfs_root *reloc_root;
2401 while (!list_empty(list)) {
2402 reloc_root = list_entry(list->next, struct btrfs_root,
2404 __del_reloc_root(reloc_root);
2405 free_extent_buffer(reloc_root->node);
2406 free_extent_buffer(reloc_root->commit_root);
2407 reloc_root->node = NULL;
2408 reloc_root->commit_root = NULL;
2412 static noinline_for_stack
2413 void merge_reloc_roots(struct reloc_control *rc)
2415 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2416 struct btrfs_root *root;
2417 struct btrfs_root *reloc_root;
2418 LIST_HEAD(reloc_roots);
2422 root = rc->extent_root;
2425 * this serializes us with btrfs_record_root_in_transaction,
2426 * we have to make sure nobody is in the middle of
2427 * adding their roots to the list while we are
2430 mutex_lock(&fs_info->reloc_mutex);
2431 list_splice_init(&rc->reloc_roots, &reloc_roots);
2432 mutex_unlock(&fs_info->reloc_mutex);
2434 while (!list_empty(&reloc_roots)) {
2436 reloc_root = list_entry(reloc_roots.next,
2437 struct btrfs_root, root_list);
2439 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2440 root = read_fs_root(fs_info,
2441 reloc_root->root_key.offset);
2442 BUG_ON(IS_ERR(root));
2443 BUG_ON(root->reloc_root != reloc_root);
2445 ret = merge_reloc_root(rc, root);
2447 if (list_empty(&reloc_root->root_list))
2448 list_add_tail(&reloc_root->root_list,
2453 list_del_init(&reloc_root->root_list);
2456 ret = btrfs_drop_snapshot(reloc_root, rc->block_rsv, 0, 1);
2458 if (list_empty(&reloc_root->root_list))
2459 list_add_tail(&reloc_root->root_list,
2471 btrfs_handle_fs_error(fs_info, ret, NULL);
2472 if (!list_empty(&reloc_roots))
2473 free_reloc_roots(&reloc_roots);
2475 /* new reloc root may be added */
2476 mutex_lock(&fs_info->reloc_mutex);
2477 list_splice_init(&rc->reloc_roots, &reloc_roots);
2478 mutex_unlock(&fs_info->reloc_mutex);
2479 if (!list_empty(&reloc_roots))
2480 free_reloc_roots(&reloc_roots);
2486 * BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2488 * here, but it's wrong. If we fail to start the transaction in
2489 * prepare_to_merge() we will have only 0 ref reloc roots, none of which
2490 * have actually been removed from the reloc_root_tree rb tree. This is
2491 * fine because we're bailing here, and we hold a reference on the root
2492 * for the list that holds it, so these roots will be cleaned up when we
2493 * do the reloc_dirty_list afterwards. Meanwhile the root->reloc_root
2494 * will be cleaned up on unmount.
2496 * The remaining nodes will be cleaned up by free_reloc_control.
2500 static void free_block_list(struct rb_root *blocks)
2502 struct tree_block *block;
2503 struct rb_node *rb_node;
2504 while ((rb_node = rb_first(blocks))) {
2505 block = rb_entry(rb_node, struct tree_block, rb_node);
2506 rb_erase(rb_node, blocks);
2511 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2512 struct btrfs_root *reloc_root)
2514 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2515 struct btrfs_root *root;
2517 if (reloc_root->last_trans == trans->transid)
2520 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2521 BUG_ON(IS_ERR(root));
2522 BUG_ON(root->reloc_root != reloc_root);
2524 return btrfs_record_root_in_trans(trans, root);
2527 static noinline_for_stack
2528 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2529 struct reloc_control *rc,
2530 struct backref_node *node,
2531 struct backref_edge *edges[])
2533 struct backref_node *next;
2534 struct btrfs_root *root;
2540 next = walk_up_backref(next, edges, &index);
2543 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2545 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2546 record_reloc_root_in_trans(trans, root);
2550 btrfs_record_root_in_trans(trans, root);
2551 root = root->reloc_root;
2553 if (next->new_bytenr != root->node->start) {
2554 BUG_ON(next->new_bytenr);
2555 BUG_ON(!list_empty(&next->list));
2556 next->new_bytenr = root->node->start;
2558 list_add_tail(&next->list,
2559 &rc->backref_cache.changed);
2560 __mark_block_processed(rc, next);
2566 next = walk_down_backref(edges, &index);
2567 if (!next || next->level <= node->level)
2574 /* setup backref node path for btrfs_reloc_cow_block */
2576 rc->backref_cache.path[next->level] = next;
2579 next = edges[index]->node[UPPER];
2585 * select a tree root for relocation. return NULL if the block
2586 * is reference counted. we should use do_relocation() in this
2587 * case. return a tree root pointer if the block isn't reference
2588 * counted. return -ENOENT if the block is root of reloc tree.
2590 static noinline_for_stack
2591 struct btrfs_root *select_one_root(struct backref_node *node)
2593 struct backref_node *next;
2594 struct btrfs_root *root;
2595 struct btrfs_root *fs_root = NULL;
2596 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2602 next = walk_up_backref(next, edges, &index);
2606 /* no other choice for non-references counted tree */
2607 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2610 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2616 next = walk_down_backref(edges, &index);
2617 if (!next || next->level <= node->level)
2622 return ERR_PTR(-ENOENT);
2626 static noinline_for_stack
2627 u64 calcu_metadata_size(struct reloc_control *rc,
2628 struct backref_node *node, int reserve)
2630 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2631 struct backref_node *next = node;
2632 struct backref_edge *edge;
2633 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2637 BUG_ON(reserve && node->processed);
2642 if (next->processed && (reserve || next != node))
2645 num_bytes += fs_info->nodesize;
2647 if (list_empty(&next->upper))
2650 edge = list_entry(next->upper.next,
2651 struct backref_edge, list[LOWER]);
2652 edges[index++] = edge;
2653 next = edge->node[UPPER];
2655 next = walk_down_backref(edges, &index);
2660 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2661 struct reloc_control *rc,
2662 struct backref_node *node)
2664 struct btrfs_root *root = rc->extent_root;
2665 struct btrfs_fs_info *fs_info = root->fs_info;
2670 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2672 trans->block_rsv = rc->block_rsv;
2673 rc->reserved_bytes += num_bytes;
2676 * We are under a transaction here so we can only do limited flushing.
2677 * If we get an enospc just kick back -EAGAIN so we know to drop the
2678 * transaction and try to refill when we can flush all the things.
2680 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2681 BTRFS_RESERVE_FLUSH_LIMIT);
2683 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2684 while (tmp <= rc->reserved_bytes)
2687 * only one thread can access block_rsv at this point,
2688 * so we don't need hold lock to protect block_rsv.
2689 * we expand more reservation size here to allow enough
2690 * space for relocation and we will return eailer in
2693 rc->block_rsv->size = tmp + fs_info->nodesize *
2694 RELOCATION_RESERVED_NODES;
2702 * relocate a block tree, and then update pointers in upper level
2703 * blocks that reference the block to point to the new location.
2705 * if called by link_to_upper, the block has already been relocated.
2706 * in that case this function just updates pointers.
2708 static int do_relocation(struct btrfs_trans_handle *trans,
2709 struct reloc_control *rc,
2710 struct backref_node *node,
2711 struct btrfs_key *key,
2712 struct btrfs_path *path, int lowest)
2714 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2715 struct backref_node *upper;
2716 struct backref_edge *edge;
2717 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2718 struct btrfs_root *root;
2719 struct extent_buffer *eb;
2727 BUG_ON(lowest && node->eb);
2729 path->lowest_level = node->level + 1;
2730 rc->backref_cache.path[node->level] = node;
2731 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2734 upper = edge->node[UPPER];
2735 root = select_reloc_root(trans, rc, upper, edges);
2738 if (upper->eb && !upper->locked) {
2740 ret = btrfs_bin_search(upper->eb, key,
2741 upper->level, &slot);
2743 bytenr = btrfs_node_blockptr(upper->eb, slot);
2744 if (node->eb->start == bytenr)
2747 drop_node_buffer(upper);
2751 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2758 btrfs_release_path(path);
2763 upper->eb = path->nodes[upper->level];
2764 path->nodes[upper->level] = NULL;
2766 BUG_ON(upper->eb != path->nodes[upper->level]);
2770 path->locks[upper->level] = 0;
2772 slot = path->slots[upper->level];
2773 btrfs_release_path(path);
2775 ret = btrfs_bin_search(upper->eb, key, upper->level,
2780 bytenr = btrfs_node_blockptr(upper->eb, slot);
2782 if (bytenr != node->bytenr) {
2783 btrfs_err(root->fs_info,
2784 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2785 bytenr, node->bytenr, slot,
2791 if (node->eb->start == bytenr)
2795 blocksize = root->fs_info->nodesize;
2796 generation = btrfs_node_ptr_generation(upper->eb, slot);
2797 eb = read_tree_block(fs_info, bytenr, generation);
2801 } else if (!extent_buffer_uptodate(eb)) {
2802 free_extent_buffer(eb);
2806 btrfs_tree_lock(eb);
2807 btrfs_set_lock_blocking(eb);
2810 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2812 btrfs_tree_unlock(eb);
2813 free_extent_buffer(eb);
2818 BUG_ON(node->eb != eb);
2820 btrfs_set_node_blockptr(upper->eb, slot,
2822 btrfs_set_node_ptr_generation(upper->eb, slot,
2824 btrfs_mark_buffer_dirty(upper->eb);
2826 ret = btrfs_inc_extent_ref(trans, root->fs_info,
2827 node->eb->start, blocksize,
2829 btrfs_header_owner(upper->eb),
2833 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2837 if (!upper->pending)
2838 drop_node_buffer(upper);
2840 unlock_node_buffer(upper);
2845 if (!err && node->pending) {
2846 drop_node_buffer(node);
2847 list_move_tail(&node->list, &rc->backref_cache.changed);
2851 path->lowest_level = 0;
2852 BUG_ON(err == -ENOSPC);
2856 static int link_to_upper(struct btrfs_trans_handle *trans,
2857 struct reloc_control *rc,
2858 struct backref_node *node,
2859 struct btrfs_path *path)
2861 struct btrfs_key key;
2863 btrfs_node_key_to_cpu(node->eb, &key, 0);
2864 return do_relocation(trans, rc, node, &key, path, 0);
2867 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2868 struct reloc_control *rc,
2869 struct btrfs_path *path, int err)
2872 struct backref_cache *cache = &rc->backref_cache;
2873 struct backref_node *node;
2877 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2878 while (!list_empty(&cache->pending[level])) {
2879 node = list_entry(cache->pending[level].next,
2880 struct backref_node, list);
2881 list_move_tail(&node->list, &list);
2882 BUG_ON(!node->pending);
2885 ret = link_to_upper(trans, rc, node, path);
2890 list_splice_init(&list, &cache->pending[level]);
2895 static void mark_block_processed(struct reloc_control *rc,
2896 u64 bytenr, u32 blocksize)
2898 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2902 static void __mark_block_processed(struct reloc_control *rc,
2903 struct backref_node *node)
2906 if (node->level == 0 ||
2907 in_block_group(node->bytenr, rc->block_group)) {
2908 blocksize = rc->extent_root->fs_info->nodesize;
2909 mark_block_processed(rc, node->bytenr, blocksize);
2911 node->processed = 1;
2915 * mark a block and all blocks directly/indirectly reference the block
2918 static void update_processed_blocks(struct reloc_control *rc,
2919 struct backref_node *node)
2921 struct backref_node *next = node;
2922 struct backref_edge *edge;
2923 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2929 if (next->processed)
2932 __mark_block_processed(rc, next);
2934 if (list_empty(&next->upper))
2937 edge = list_entry(next->upper.next,
2938 struct backref_edge, list[LOWER]);
2939 edges[index++] = edge;
2940 next = edge->node[UPPER];
2942 next = walk_down_backref(edges, &index);
2946 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
2948 u32 blocksize = rc->extent_root->fs_info->nodesize;
2950 if (test_range_bit(&rc->processed_blocks, bytenr,
2951 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
2956 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
2957 struct tree_block *block)
2959 struct extent_buffer *eb;
2961 BUG_ON(block->key_ready);
2962 eb = read_tree_block(fs_info, block->bytenr, block->key.offset);
2965 } else if (!extent_buffer_uptodate(eb)) {
2966 free_extent_buffer(eb);
2969 WARN_ON(btrfs_header_level(eb) != block->level);
2970 if (block->level == 0)
2971 btrfs_item_key_to_cpu(eb, &block->key, 0);
2973 btrfs_node_key_to_cpu(eb, &block->key, 0);
2974 free_extent_buffer(eb);
2975 block->key_ready = 1;
2980 * helper function to relocate a tree block
2982 static int relocate_tree_block(struct btrfs_trans_handle *trans,
2983 struct reloc_control *rc,
2984 struct backref_node *node,
2985 struct btrfs_key *key,
2986 struct btrfs_path *path)
2988 struct btrfs_root *root;
2994 BUG_ON(node->processed);
2995 root = select_one_root(node);
2996 if (root == ERR_PTR(-ENOENT)) {
2997 update_processed_blocks(rc, node);
3001 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3002 ret = reserve_metadata_space(trans, rc, node);
3008 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3009 BUG_ON(node->new_bytenr);
3010 BUG_ON(!list_empty(&node->list));
3011 btrfs_record_root_in_trans(trans, root);
3012 root = root->reloc_root;
3013 node->new_bytenr = root->node->start;
3015 list_add_tail(&node->list, &rc->backref_cache.changed);
3017 path->lowest_level = node->level;
3018 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3019 btrfs_release_path(path);
3024 update_processed_blocks(rc, node);
3026 ret = do_relocation(trans, rc, node, key, path, 1);
3029 if (ret || node->level == 0 || node->cowonly)
3030 remove_backref_node(&rc->backref_cache, node);
3035 * relocate a list of blocks
3037 static noinline_for_stack
3038 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3039 struct reloc_control *rc, struct rb_root *blocks)
3041 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3042 struct backref_node *node;
3043 struct btrfs_path *path;
3044 struct tree_block *block;
3045 struct rb_node *rb_node;
3049 path = btrfs_alloc_path();
3052 goto out_free_blocks;
3055 rb_node = rb_first(blocks);
3057 block = rb_entry(rb_node, struct tree_block, rb_node);
3058 if (!block->key_ready)
3059 readahead_tree_block(fs_info, block->bytenr);
3060 rb_node = rb_next(rb_node);
3063 rb_node = rb_first(blocks);
3065 block = rb_entry(rb_node, struct tree_block, rb_node);
3066 if (!block->key_ready) {
3067 err = get_tree_block_key(fs_info, block);
3071 rb_node = rb_next(rb_node);
3074 rb_node = rb_first(blocks);
3076 block = rb_entry(rb_node, struct tree_block, rb_node);
3078 node = build_backref_tree(rc, &block->key,
3079 block->level, block->bytenr);
3081 err = PTR_ERR(node);
3085 ret = relocate_tree_block(trans, rc, node, &block->key,
3088 if (ret != -EAGAIN || rb_node == rb_first(blocks))
3092 rb_node = rb_next(rb_node);
3095 err = finish_pending_nodes(trans, rc, path, err);
3098 btrfs_free_path(path);
3100 free_block_list(blocks);
3104 static noinline_for_stack
3105 int prealloc_file_extent_cluster(struct inode *inode,
3106 struct file_extent_cluster *cluster)
3111 u64 offset = BTRFS_I(inode)->index_cnt;
3115 u64 prealloc_start = cluster->start - offset;
3116 u64 prealloc_end = cluster->end - offset;
3118 struct extent_changeset *data_reserved = NULL;
3120 BUG_ON(cluster->start != cluster->boundary[0]);
3123 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3124 prealloc_end + 1 - prealloc_start);
3128 cur_offset = prealloc_start;
3129 while (nr < cluster->nr) {
3130 start = cluster->boundary[nr] - offset;
3131 if (nr + 1 < cluster->nr)
3132 end = cluster->boundary[nr + 1] - 1 - offset;
3134 end = cluster->end - offset;
3136 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3137 num_bytes = end + 1 - start;
3138 if (cur_offset < start)
3139 btrfs_free_reserved_data_space(inode, data_reserved,
3140 cur_offset, start - cur_offset);
3141 ret = btrfs_prealloc_file_range(inode, 0, start,
3142 num_bytes, num_bytes,
3143 end + 1, &alloc_hint);
3144 cur_offset = end + 1;
3145 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3150 if (cur_offset < prealloc_end)
3151 btrfs_free_reserved_data_space(inode, data_reserved,
3152 cur_offset, prealloc_end + 1 - cur_offset);
3154 inode_unlock(inode);
3155 extent_changeset_free(data_reserved);
3159 static noinline_for_stack
3160 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3163 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3164 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3165 struct extent_map *em;
3168 em = alloc_extent_map();
3173 em->len = end + 1 - start;
3174 em->block_len = em->len;
3175 em->block_start = block_start;
3176 em->bdev = fs_info->fs_devices->latest_bdev;
3177 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3179 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3181 write_lock(&em_tree->lock);
3182 ret = add_extent_mapping(em_tree, em, 0);
3183 write_unlock(&em_tree->lock);
3184 if (ret != -EEXIST) {
3185 free_extent_map(em);
3188 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3190 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3194 static int relocate_file_extent_cluster(struct inode *inode,
3195 struct file_extent_cluster *cluster)
3197 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3200 u64 offset = BTRFS_I(inode)->index_cnt;
3201 unsigned long index;
3202 unsigned long last_index;
3204 struct file_ra_state *ra;
3205 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3212 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3216 ret = prealloc_file_extent_cluster(inode, cluster);
3220 file_ra_state_init(ra, inode->i_mapping);
3222 ret = setup_extent_mapping(inode, cluster->start - offset,
3223 cluster->end - offset, cluster->start);
3227 index = (cluster->start - offset) >> PAGE_SHIFT;
3228 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3229 while (index <= last_index) {
3230 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3235 page = find_lock_page(inode->i_mapping, index);
3237 page_cache_sync_readahead(inode->i_mapping,
3239 last_index + 1 - index);
3240 page = find_or_create_page(inode->i_mapping, index,
3243 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3250 if (PageReadahead(page)) {
3251 page_cache_async_readahead(inode->i_mapping,
3252 ra, NULL, page, index,
3253 last_index + 1 - index);
3256 if (!PageUptodate(page)) {
3257 btrfs_readpage(NULL, page);
3259 if (!PageUptodate(page)) {
3262 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3269 page_start = page_offset(page);
3270 page_end = page_start + PAGE_SIZE - 1;
3272 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3274 set_page_extent_mapped(page);
3276 if (nr < cluster->nr &&
3277 page_start + offset == cluster->boundary[nr]) {
3278 set_extent_bits(&BTRFS_I(inode)->io_tree,
3279 page_start, page_end,
3284 btrfs_set_extent_delalloc(inode, page_start, page_end, NULL, 0);
3285 set_page_dirty(page);
3287 unlock_extent(&BTRFS_I(inode)->io_tree,
3288 page_start, page_end);
3293 balance_dirty_pages_ratelimited(inode->i_mapping);
3294 btrfs_throttle(fs_info);
3296 WARN_ON(nr != cluster->nr);
3302 static noinline_for_stack
3303 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3304 struct file_extent_cluster *cluster)
3308 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3309 ret = relocate_file_extent_cluster(inode, cluster);
3316 cluster->start = extent_key->objectid;
3318 BUG_ON(cluster->nr >= MAX_EXTENTS);
3319 cluster->end = extent_key->objectid + extent_key->offset - 1;
3320 cluster->boundary[cluster->nr] = extent_key->objectid;
3323 if (cluster->nr >= MAX_EXTENTS) {
3324 ret = relocate_file_extent_cluster(inode, cluster);
3332 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3333 static int get_ref_objectid_v0(struct reloc_control *rc,
3334 struct btrfs_path *path,
3335 struct btrfs_key *extent_key,
3336 u64 *ref_objectid, int *path_change)
3338 struct btrfs_key key;
3339 struct extent_buffer *leaf;
3340 struct btrfs_extent_ref_v0 *ref0;
3344 leaf = path->nodes[0];
3345 slot = path->slots[0];
3347 if (slot >= btrfs_header_nritems(leaf)) {
3348 ret = btrfs_next_leaf(rc->extent_root, path);
3352 leaf = path->nodes[0];
3353 slot = path->slots[0];
3357 btrfs_item_key_to_cpu(leaf, &key, slot);
3358 if (key.objectid != extent_key->objectid)
3361 if (key.type != BTRFS_EXTENT_REF_V0_KEY) {
3365 ref0 = btrfs_item_ptr(leaf, slot,
3366 struct btrfs_extent_ref_v0);
3367 *ref_objectid = btrfs_ref_objectid_v0(leaf, ref0);
3375 * helper to add a tree block to the list.
3376 * the major work is getting the generation and level of the block
3378 static int add_tree_block(struct reloc_control *rc,
3379 struct btrfs_key *extent_key,
3380 struct btrfs_path *path,
3381 struct rb_root *blocks)
3383 struct extent_buffer *eb;
3384 struct btrfs_extent_item *ei;
3385 struct btrfs_tree_block_info *bi;
3386 struct tree_block *block;
3387 struct rb_node *rb_node;
3392 eb = path->nodes[0];
3393 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3395 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3396 item_size >= sizeof(*ei) + sizeof(*bi)) {
3397 ei = btrfs_item_ptr(eb, path->slots[0],
3398 struct btrfs_extent_item);
3399 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3400 bi = (struct btrfs_tree_block_info *)(ei + 1);
3401 level = btrfs_tree_block_level(eb, bi);
3403 level = (int)extent_key->offset;
3405 generation = btrfs_extent_generation(eb, ei);
3407 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3411 BUG_ON(item_size != sizeof(struct btrfs_extent_item_v0));
3412 ret = get_ref_objectid_v0(rc, path, extent_key,
3416 BUG_ON(ref_owner >= BTRFS_MAX_LEVEL);
3417 level = (int)ref_owner;
3418 /* FIXME: get real generation */
3425 btrfs_release_path(path);
3427 BUG_ON(level == -1);
3429 block = kmalloc(sizeof(*block), GFP_NOFS);
3433 block->bytenr = extent_key->objectid;
3434 block->key.objectid = rc->extent_root->fs_info->nodesize;
3435 block->key.offset = generation;
3436 block->level = level;
3437 block->key_ready = 0;
3439 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3441 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3447 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3449 static int __add_tree_block(struct reloc_control *rc,
3450 u64 bytenr, u32 blocksize,
3451 struct rb_root *blocks)
3453 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3454 struct btrfs_path *path;
3455 struct btrfs_key key;
3457 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3459 if (tree_block_processed(bytenr, rc))
3462 if (tree_search(blocks, bytenr))
3465 path = btrfs_alloc_path();
3469 key.objectid = bytenr;
3471 key.type = BTRFS_METADATA_ITEM_KEY;
3472 key.offset = (u64)-1;
3474 key.type = BTRFS_EXTENT_ITEM_KEY;
3475 key.offset = blocksize;
3478 path->search_commit_root = 1;
3479 path->skip_locking = 1;
3480 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3484 if (ret > 0 && skinny) {
3485 if (path->slots[0]) {
3487 btrfs_item_key_to_cpu(path->nodes[0], &key,
3489 if (key.objectid == bytenr &&
3490 (key.type == BTRFS_METADATA_ITEM_KEY ||
3491 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3492 key.offset == blocksize)))
3498 btrfs_release_path(path);
3504 btrfs_print_leaf(path->nodes[0]);
3506 "tree block extent item (%llu) is not found in extent tree",
3513 ret = add_tree_block(rc, &key, path, blocks);
3515 btrfs_free_path(path);
3520 * helper to check if the block use full backrefs for pointers in it
3522 static int block_use_full_backref(struct reloc_control *rc,
3523 struct extent_buffer *eb)
3528 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3529 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3532 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3533 eb->start, btrfs_header_level(eb), 1,
3537 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3544 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3545 struct btrfs_block_group_cache *block_group,
3546 struct inode *inode,
3549 struct btrfs_key key;
3550 struct btrfs_root *root = fs_info->tree_root;
3551 struct btrfs_trans_handle *trans;
3558 key.type = BTRFS_INODE_ITEM_KEY;
3561 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
3562 if (IS_ERR(inode) || is_bad_inode(inode)) {
3569 ret = btrfs_check_trunc_cache_free_space(fs_info,
3570 &fs_info->global_block_rsv);
3574 trans = btrfs_join_transaction(root);
3575 if (IS_ERR(trans)) {
3576 ret = PTR_ERR(trans);
3580 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3582 btrfs_end_transaction(trans);
3583 btrfs_btree_balance_dirty(fs_info);
3590 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3591 * this function scans fs tree to find blocks reference the data extent
3593 static int find_data_references(struct reloc_control *rc,
3594 struct btrfs_key *extent_key,
3595 struct extent_buffer *leaf,
3596 struct btrfs_extent_data_ref *ref,
3597 struct rb_root *blocks)
3599 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3600 struct btrfs_path *path;
3601 struct tree_block *block;
3602 struct btrfs_root *root;
3603 struct btrfs_file_extent_item *fi;
3604 struct rb_node *rb_node;
3605 struct btrfs_key key;
3616 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3617 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3618 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3619 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3622 * This is an extent belonging to the free space cache, lets just delete
3623 * it and redo the search.
3625 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3626 ret = delete_block_group_cache(fs_info, rc->block_group,
3627 NULL, ref_objectid);
3633 path = btrfs_alloc_path();
3636 path->reada = READA_FORWARD;
3638 root = read_fs_root(fs_info, ref_root);
3640 err = PTR_ERR(root);
3644 key.objectid = ref_objectid;
3645 key.type = BTRFS_EXTENT_DATA_KEY;
3646 if (ref_offset > ((u64)-1 << 32))
3649 key.offset = ref_offset;
3651 path->search_commit_root = 1;
3652 path->skip_locking = 1;
3653 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3659 leaf = path->nodes[0];
3660 nritems = btrfs_header_nritems(leaf);
3662 * the references in tree blocks that use full backrefs
3663 * are not counted in
3665 if (block_use_full_backref(rc, leaf))
3669 rb_node = tree_search(blocks, leaf->start);
3674 path->slots[0] = nritems;
3677 while (ref_count > 0) {
3678 while (path->slots[0] >= nritems) {
3679 ret = btrfs_next_leaf(root, path);
3684 if (WARN_ON(ret > 0))
3687 leaf = path->nodes[0];
3688 nritems = btrfs_header_nritems(leaf);
3691 if (block_use_full_backref(rc, leaf))
3695 rb_node = tree_search(blocks, leaf->start);
3700 path->slots[0] = nritems;
3704 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3705 if (WARN_ON(key.objectid != ref_objectid ||
3706 key.type != BTRFS_EXTENT_DATA_KEY))
3709 fi = btrfs_item_ptr(leaf, path->slots[0],
3710 struct btrfs_file_extent_item);
3712 if (btrfs_file_extent_type(leaf, fi) ==
3713 BTRFS_FILE_EXTENT_INLINE)
3716 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3717 extent_key->objectid)
3720 key.offset -= btrfs_file_extent_offset(leaf, fi);
3721 if (key.offset != ref_offset)
3729 if (!tree_block_processed(leaf->start, rc)) {
3730 block = kmalloc(sizeof(*block), GFP_NOFS);
3735 block->bytenr = leaf->start;
3736 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3738 block->key_ready = 1;
3739 rb_node = tree_insert(blocks, block->bytenr,
3742 backref_tree_panic(rb_node, -EEXIST,
3748 path->slots[0] = nritems;
3754 btrfs_free_path(path);
3759 * helper to find all tree blocks that reference a given data extent
3761 static noinline_for_stack
3762 int add_data_references(struct reloc_control *rc,
3763 struct btrfs_key *extent_key,
3764 struct btrfs_path *path,
3765 struct rb_root *blocks)
3767 struct btrfs_key key;
3768 struct extent_buffer *eb;
3769 struct btrfs_extent_data_ref *dref;
3770 struct btrfs_extent_inline_ref *iref;
3773 u32 blocksize = rc->extent_root->fs_info->nodesize;
3777 eb = path->nodes[0];
3778 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3779 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3780 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3781 if (ptr + sizeof(struct btrfs_extent_item_v0) == end)
3785 ptr += sizeof(struct btrfs_extent_item);
3788 iref = (struct btrfs_extent_inline_ref *)ptr;
3789 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3790 BTRFS_REF_TYPE_DATA);
3791 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3792 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3793 ret = __add_tree_block(rc, key.offset, blocksize,
3795 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3796 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3797 ret = find_data_references(rc, extent_key,
3801 btrfs_err(rc->extent_root->fs_info,
3802 "extent %llu slot %d has an invalid inline ref type",
3803 eb->start, path->slots[0]);
3809 ptr += btrfs_extent_inline_ref_size(key.type);
3815 eb = path->nodes[0];
3816 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3817 ret = btrfs_next_leaf(rc->extent_root, path);
3824 eb = path->nodes[0];
3827 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3828 if (key.objectid != extent_key->objectid)
3831 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
3832 if (key.type == BTRFS_SHARED_DATA_REF_KEY ||
3833 key.type == BTRFS_EXTENT_REF_V0_KEY) {
3835 BUG_ON(key.type == BTRFS_EXTENT_REF_V0_KEY);
3836 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3838 ret = __add_tree_block(rc, key.offset, blocksize,
3840 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3841 dref = btrfs_item_ptr(eb, path->slots[0],
3842 struct btrfs_extent_data_ref);
3843 ret = find_data_references(rc, extent_key,
3855 btrfs_release_path(path);
3857 free_block_list(blocks);
3862 * helper to find next unprocessed extent
3864 static noinline_for_stack
3865 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3866 struct btrfs_key *extent_key)
3868 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3869 struct btrfs_key key;
3870 struct extent_buffer *leaf;
3871 u64 start, end, last;
3874 last = rc->block_group->key.objectid + rc->block_group->key.offset;
3877 if (rc->search_start >= last) {
3882 key.objectid = rc->search_start;
3883 key.type = BTRFS_EXTENT_ITEM_KEY;
3886 path->search_commit_root = 1;
3887 path->skip_locking = 1;
3888 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3893 leaf = path->nodes[0];
3894 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3895 ret = btrfs_next_leaf(rc->extent_root, path);
3898 leaf = path->nodes[0];
3901 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3902 if (key.objectid >= last) {
3907 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3908 key.type != BTRFS_METADATA_ITEM_KEY) {
3913 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3914 key.objectid + key.offset <= rc->search_start) {
3919 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3920 key.objectid + fs_info->nodesize <=
3926 ret = find_first_extent_bit(&rc->processed_blocks,
3927 key.objectid, &start, &end,
3928 EXTENT_DIRTY, NULL);
3930 if (ret == 0 && start <= key.objectid) {
3931 btrfs_release_path(path);
3932 rc->search_start = end + 1;
3934 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3935 rc->search_start = key.objectid + key.offset;
3937 rc->search_start = key.objectid +
3939 memcpy(extent_key, &key, sizeof(key));
3943 btrfs_release_path(path);
3947 static void set_reloc_control(struct reloc_control *rc)
3949 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3951 mutex_lock(&fs_info->reloc_mutex);
3952 fs_info->reloc_ctl = rc;
3953 mutex_unlock(&fs_info->reloc_mutex);
3956 static void unset_reloc_control(struct reloc_control *rc)
3958 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3960 mutex_lock(&fs_info->reloc_mutex);
3961 fs_info->reloc_ctl = NULL;
3962 mutex_unlock(&fs_info->reloc_mutex);
3965 static int check_extent_flags(u64 flags)
3967 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3968 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3970 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
3971 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
3973 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3974 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
3979 static noinline_for_stack
3980 int prepare_to_relocate(struct reloc_control *rc)
3982 struct btrfs_trans_handle *trans;
3985 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
3986 BTRFS_BLOCK_RSV_TEMP);
3990 memset(&rc->cluster, 0, sizeof(rc->cluster));
3991 rc->search_start = rc->block_group->key.objectid;
3992 rc->extents_found = 0;
3993 rc->nodes_relocated = 0;
3994 rc->merging_rsv_size = 0;
3995 rc->reserved_bytes = 0;
3996 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
3997 RELOCATION_RESERVED_NODES;
3998 ret = btrfs_block_rsv_refill(rc->extent_root,
3999 rc->block_rsv, rc->block_rsv->size,
4000 BTRFS_RESERVE_FLUSH_ALL);
4004 rc->create_reloc_tree = 1;
4005 set_reloc_control(rc);
4007 trans = btrfs_join_transaction(rc->extent_root);
4008 if (IS_ERR(trans)) {
4009 unset_reloc_control(rc);
4011 * extent tree is not a ref_cow tree and has no reloc_root to
4012 * cleanup. And callers are responsible to free the above
4015 return PTR_ERR(trans);
4017 btrfs_commit_transaction(trans);
4021 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4023 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4024 struct rb_root blocks = RB_ROOT;
4025 struct btrfs_key key;
4026 struct btrfs_trans_handle *trans = NULL;
4027 struct btrfs_path *path;
4028 struct btrfs_extent_item *ei;
4035 path = btrfs_alloc_path();
4038 path->reada = READA_FORWARD;
4040 ret = prepare_to_relocate(rc);
4047 rc->reserved_bytes = 0;
4048 ret = btrfs_block_rsv_refill(rc->extent_root,
4049 rc->block_rsv, rc->block_rsv->size,
4050 BTRFS_RESERVE_FLUSH_ALL);
4056 trans = btrfs_start_transaction(rc->extent_root, 0);
4057 if (IS_ERR(trans)) {
4058 err = PTR_ERR(trans);
4063 if (update_backref_cache(trans, &rc->backref_cache)) {
4064 btrfs_end_transaction(trans);
4069 ret = find_next_extent(rc, path, &key);
4075 rc->extents_found++;
4077 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4078 struct btrfs_extent_item);
4079 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4080 if (item_size >= sizeof(*ei)) {
4081 flags = btrfs_extent_flags(path->nodes[0], ei);
4082 ret = check_extent_flags(flags);
4086 #ifdef BTRFS_COMPAT_EXTENT_TREE_V0
4088 int path_change = 0;
4091 sizeof(struct btrfs_extent_item_v0));
4092 ret = get_ref_objectid_v0(rc, path, &key, &ref_owner,
4098 if (ref_owner < BTRFS_FIRST_FREE_OBJECTID)
4099 flags = BTRFS_EXTENT_FLAG_TREE_BLOCK;
4101 flags = BTRFS_EXTENT_FLAG_DATA;
4104 btrfs_release_path(path);
4106 path->search_commit_root = 1;
4107 path->skip_locking = 1;
4108 ret = btrfs_search_slot(NULL, rc->extent_root,
4121 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4122 ret = add_tree_block(rc, &key, path, &blocks);
4123 } else if (rc->stage == UPDATE_DATA_PTRS &&
4124 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4125 ret = add_data_references(rc, &key, path, &blocks);
4127 btrfs_release_path(path);
4135 if (!RB_EMPTY_ROOT(&blocks)) {
4136 ret = relocate_tree_blocks(trans, rc, &blocks);
4139 * if we fail to relocate tree blocks, force to update
4140 * backref cache when committing transaction.
4142 rc->backref_cache.last_trans = trans->transid - 1;
4144 if (ret != -EAGAIN) {
4148 rc->extents_found--;
4149 rc->search_start = key.objectid;
4153 btrfs_end_transaction_throttle(trans);
4154 btrfs_btree_balance_dirty(fs_info);
4157 if (rc->stage == MOVE_DATA_EXTENTS &&
4158 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4159 rc->found_file_extent = 1;
4160 ret = relocate_data_extent(rc->data_inode,
4161 &key, &rc->cluster);
4168 if (trans && progress && err == -ENOSPC) {
4169 ret = btrfs_force_chunk_alloc(trans, fs_info,
4170 rc->block_group->flags);
4178 btrfs_release_path(path);
4179 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4182 btrfs_end_transaction_throttle(trans);
4183 btrfs_btree_balance_dirty(fs_info);
4187 ret = relocate_file_extent_cluster(rc->data_inode,
4193 rc->create_reloc_tree = 0;
4194 set_reloc_control(rc);
4196 backref_cache_cleanup(&rc->backref_cache);
4197 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4199 err = prepare_to_merge(rc, err);
4201 merge_reloc_roots(rc);
4203 rc->merge_reloc_tree = 0;
4204 unset_reloc_control(rc);
4205 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4207 /* get rid of pinned extents */
4208 trans = btrfs_join_transaction(rc->extent_root);
4209 if (IS_ERR(trans)) {
4210 err = PTR_ERR(trans);
4213 btrfs_commit_transaction(trans);
4215 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4216 btrfs_free_path(path);
4220 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4221 struct btrfs_root *root, u64 objectid)
4223 struct btrfs_path *path;
4224 struct btrfs_inode_item *item;
4225 struct extent_buffer *leaf;
4228 path = btrfs_alloc_path();
4232 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4236 leaf = path->nodes[0];
4237 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4238 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4239 btrfs_set_inode_generation(leaf, item, 1);
4240 btrfs_set_inode_size(leaf, item, 0);
4241 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4242 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4243 BTRFS_INODE_PREALLOC);
4244 btrfs_mark_buffer_dirty(leaf);
4246 btrfs_free_path(path);
4251 * helper to create inode for data relocation.
4252 * the inode is in data relocation tree and its link count is 0
4254 static noinline_for_stack
4255 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4256 struct btrfs_block_group_cache *group)
4258 struct inode *inode = NULL;
4259 struct btrfs_trans_handle *trans;
4260 struct btrfs_root *root;
4261 struct btrfs_key key;
4265 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4267 return ERR_CAST(root);
4269 trans = btrfs_start_transaction(root, 6);
4271 return ERR_CAST(trans);
4273 err = btrfs_find_free_objectid(root, &objectid);
4277 err = __insert_orphan_inode(trans, root, objectid);
4280 key.objectid = objectid;
4281 key.type = BTRFS_INODE_ITEM_KEY;
4283 inode = btrfs_iget(fs_info->sb, &key, root, NULL);
4284 BUG_ON(IS_ERR(inode) || is_bad_inode(inode));
4285 BTRFS_I(inode)->index_cnt = group->key.objectid;
4287 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4289 btrfs_end_transaction(trans);
4290 btrfs_btree_balance_dirty(fs_info);
4294 inode = ERR_PTR(err);
4299 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4301 struct reloc_control *rc;
4303 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4307 INIT_LIST_HEAD(&rc->reloc_roots);
4308 backref_cache_init(&rc->backref_cache);
4309 mapping_tree_init(&rc->reloc_root_tree);
4310 extent_io_tree_init(&rc->processed_blocks, NULL);
4315 * Print the block group being relocated
4317 static void describe_relocation(struct btrfs_fs_info *fs_info,
4318 struct btrfs_block_group_cache *block_group)
4320 char buf[128]; /* prefixed by a '|' that'll be dropped */
4321 u64 flags = block_group->flags;
4323 /* Shouldn't happen */
4325 strcpy(buf, "|NONE");
4329 #define DESCRIBE_FLAG(f, d) \
4330 if (flags & BTRFS_BLOCK_GROUP_##f) { \
4331 bp += snprintf(bp, buf - bp + sizeof(buf), "|%s", d); \
4332 flags &= ~BTRFS_BLOCK_GROUP_##f; \
4334 DESCRIBE_FLAG(DATA, "data");
4335 DESCRIBE_FLAG(SYSTEM, "system");
4336 DESCRIBE_FLAG(METADATA, "metadata");
4337 DESCRIBE_FLAG(RAID0, "raid0");
4338 DESCRIBE_FLAG(RAID1, "raid1");
4339 DESCRIBE_FLAG(DUP, "dup");
4340 DESCRIBE_FLAG(RAID10, "raid10");
4341 DESCRIBE_FLAG(RAID5, "raid5");
4342 DESCRIBE_FLAG(RAID6, "raid6");
4344 snprintf(buf, buf - bp + sizeof(buf), "|0x%llx", flags);
4345 #undef DESCRIBE_FLAG
4349 "relocating block group %llu flags %s",
4350 block_group->key.objectid, buf + 1);
4354 * function to relocate all extents in a block group.
4356 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4358 struct btrfs_root *extent_root = fs_info->extent_root;
4359 struct reloc_control *rc;
4360 struct inode *inode;
4361 struct btrfs_path *path;
4366 rc = alloc_reloc_control(fs_info);
4370 rc->extent_root = extent_root;
4372 rc->block_group = btrfs_lookup_block_group(fs_info, group_start);
4373 BUG_ON(!rc->block_group);
4375 ret = btrfs_inc_block_group_ro(fs_info, rc->block_group);
4382 path = btrfs_alloc_path();
4388 inode = lookup_free_space_inode(fs_info, rc->block_group, path);
4389 btrfs_free_path(path);
4392 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4394 ret = PTR_ERR(inode);
4396 if (ret && ret != -ENOENT) {
4401 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4402 if (IS_ERR(rc->data_inode)) {
4403 err = PTR_ERR(rc->data_inode);
4404 rc->data_inode = NULL;
4408 describe_relocation(fs_info, rc->block_group);
4410 btrfs_wait_block_group_reservations(rc->block_group);
4411 btrfs_wait_nocow_writers(rc->block_group);
4412 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4413 rc->block_group->key.objectid,
4414 rc->block_group->key.offset);
4417 mutex_lock(&fs_info->cleaner_mutex);
4418 ret = relocate_block_group(rc);
4419 mutex_unlock(&fs_info->cleaner_mutex);
4424 * We may have gotten ENOSPC after we already dirtied some
4425 * extents. If writeout happens while we're relocating a
4426 * different block group we could end up hitting the
4427 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4428 * btrfs_reloc_cow_block. Make sure we write everything out
4429 * properly so we don't trip over this problem, and then break
4430 * out of the loop if we hit an error.
4432 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4433 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4437 invalidate_mapping_pages(rc->data_inode->i_mapping,
4439 rc->stage = UPDATE_DATA_PTRS;
4445 if (rc->extents_found == 0)
4448 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4452 WARN_ON(rc->block_group->pinned > 0);
4453 WARN_ON(rc->block_group->reserved > 0);
4454 WARN_ON(btrfs_block_group_used(&rc->block_group->item) > 0);
4457 btrfs_dec_block_group_ro(rc->block_group);
4458 iput(rc->data_inode);
4459 btrfs_put_block_group(rc->block_group);
4464 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4466 struct btrfs_fs_info *fs_info = root->fs_info;
4467 struct btrfs_trans_handle *trans;
4470 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4472 return PTR_ERR(trans);
4474 memset(&root->root_item.drop_progress, 0,
4475 sizeof(root->root_item.drop_progress));
4476 root->root_item.drop_level = 0;
4477 btrfs_set_root_refs(&root->root_item, 0);
4478 ret = btrfs_update_root(trans, fs_info->tree_root,
4479 &root->root_key, &root->root_item);
4481 err = btrfs_end_transaction(trans);
4488 * recover relocation interrupted by system crash.
4490 * this function resumes merging reloc trees with corresponding fs trees.
4491 * this is important for keeping the sharing of tree blocks
4493 int btrfs_recover_relocation(struct btrfs_root *root)
4495 struct btrfs_fs_info *fs_info = root->fs_info;
4496 LIST_HEAD(reloc_roots);
4497 struct btrfs_key key;
4498 struct btrfs_root *fs_root;
4499 struct btrfs_root *reloc_root;
4500 struct btrfs_path *path;
4501 struct extent_buffer *leaf;
4502 struct reloc_control *rc = NULL;
4503 struct btrfs_trans_handle *trans;
4507 path = btrfs_alloc_path();
4510 path->reada = READA_BACK;
4512 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4513 key.type = BTRFS_ROOT_ITEM_KEY;
4514 key.offset = (u64)-1;
4517 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4524 if (path->slots[0] == 0)
4528 leaf = path->nodes[0];
4529 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4530 btrfs_release_path(path);
4532 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4533 key.type != BTRFS_ROOT_ITEM_KEY)
4536 reloc_root = btrfs_read_fs_root(root, &key);
4537 if (IS_ERR(reloc_root)) {
4538 err = PTR_ERR(reloc_root);
4542 list_add(&reloc_root->root_list, &reloc_roots);
4544 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4545 fs_root = read_fs_root(fs_info,
4546 reloc_root->root_key.offset);
4547 if (IS_ERR(fs_root)) {
4548 ret = PTR_ERR(fs_root);
4549 if (ret != -ENOENT) {
4553 ret = mark_garbage_root(reloc_root);
4561 if (key.offset == 0)
4566 btrfs_release_path(path);
4568 if (list_empty(&reloc_roots))
4571 rc = alloc_reloc_control(fs_info);
4577 rc->extent_root = fs_info->extent_root;
4579 set_reloc_control(rc);
4581 trans = btrfs_join_transaction(rc->extent_root);
4582 if (IS_ERR(trans)) {
4583 unset_reloc_control(rc);
4584 err = PTR_ERR(trans);
4588 rc->merge_reloc_tree = 1;
4590 while (!list_empty(&reloc_roots)) {
4591 reloc_root = list_entry(reloc_roots.next,
4592 struct btrfs_root, root_list);
4593 list_del(&reloc_root->root_list);
4595 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4596 list_add_tail(&reloc_root->root_list,
4601 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4602 if (IS_ERR(fs_root)) {
4603 err = PTR_ERR(fs_root);
4604 list_add_tail(&reloc_root->root_list, &reloc_roots);
4608 err = __add_reloc_root(reloc_root);
4609 BUG_ON(err < 0); /* -ENOMEM or logic error */
4610 fs_root->reloc_root = reloc_root;
4613 err = btrfs_commit_transaction(trans);
4617 merge_reloc_roots(rc);
4619 unset_reloc_control(rc);
4621 trans = btrfs_join_transaction(rc->extent_root);
4622 if (IS_ERR(trans)) {
4623 err = PTR_ERR(trans);
4626 err = btrfs_commit_transaction(trans);
4630 if (!list_empty(&reloc_roots))
4631 free_reloc_roots(&reloc_roots);
4633 btrfs_free_path(path);
4636 /* cleanup orphan inode in data relocation tree */
4637 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4638 if (IS_ERR(fs_root))
4639 err = PTR_ERR(fs_root);
4641 err = btrfs_orphan_cleanup(fs_root);
4647 * helper to add ordered checksum for data relocation.
4649 * cloning checksum properly handles the nodatasum extents.
4650 * it also saves CPU time to re-calculate the checksum.
4652 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4654 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4655 struct btrfs_ordered_sum *sums;
4656 struct btrfs_ordered_extent *ordered;
4662 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4663 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4665 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4666 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4667 disk_bytenr + len - 1, &list, 0);
4671 while (!list_empty(&list)) {
4672 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4673 list_del_init(&sums->list);
4676 * We need to offset the new_bytenr based on where the csum is.
4677 * We need to do this because we will read in entire prealloc
4678 * extents but we may have written to say the middle of the
4679 * prealloc extent, so we need to make sure the csum goes with
4680 * the right disk offset.
4682 * We can do this because the data reloc inode refers strictly
4683 * to the on disk bytes, so we don't have to worry about
4684 * disk_len vs real len like with real inodes since it's all
4687 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4688 sums->bytenr = new_bytenr;
4690 btrfs_add_ordered_sum(inode, ordered, sums);
4693 btrfs_put_ordered_extent(ordered);
4697 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4698 struct btrfs_root *root, struct extent_buffer *buf,
4699 struct extent_buffer *cow)
4701 struct btrfs_fs_info *fs_info = root->fs_info;
4702 struct reloc_control *rc;
4703 struct backref_node *node;
4708 rc = fs_info->reloc_ctl;
4712 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4713 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4715 level = btrfs_header_level(buf);
4716 if (btrfs_header_generation(buf) <=
4717 btrfs_root_last_snapshot(&root->root_item))
4720 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4721 rc->create_reloc_tree) {
4722 WARN_ON(!first_cow && level == 0);
4724 node = rc->backref_cache.path[level];
4725 BUG_ON(node->bytenr != buf->start &&
4726 node->new_bytenr != buf->start);
4728 drop_node_buffer(node);
4729 extent_buffer_get(cow);
4731 node->new_bytenr = cow->start;
4733 if (!node->pending) {
4734 list_move_tail(&node->list,
4735 &rc->backref_cache.pending[level]);
4740 __mark_block_processed(rc, node);
4742 if (first_cow && level > 0)
4743 rc->nodes_relocated += buf->len;
4746 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4747 ret = replace_file_extents(trans, rc, root, cow);
4752 * called before creating snapshot. it calculates metadata reservation
4753 * required for relocating tree blocks in the snapshot
4755 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4756 u64 *bytes_to_reserve)
4758 struct btrfs_root *root;
4759 struct reloc_control *rc;
4761 root = pending->root;
4762 if (!root->reloc_root)
4765 rc = root->fs_info->reloc_ctl;
4766 if (!rc->merge_reloc_tree)
4769 root = root->reloc_root;
4770 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4772 * relocation is in the stage of merging trees. the space
4773 * used by merging a reloc tree is twice the size of
4774 * relocated tree nodes in the worst case. half for cowing
4775 * the reloc tree, half for cowing the fs tree. the space
4776 * used by cowing the reloc tree will be freed after the
4777 * tree is dropped. if we create snapshot, cowing the fs
4778 * tree may use more space than it frees. so we need
4779 * reserve extra space.
4781 *bytes_to_reserve += rc->nodes_relocated;
4785 * called after snapshot is created. migrate block reservation
4786 * and create reloc root for the newly created snapshot
4788 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4789 struct btrfs_pending_snapshot *pending)
4791 struct btrfs_root *root = pending->root;
4792 struct btrfs_root *reloc_root;
4793 struct btrfs_root *new_root;
4794 struct reloc_control *rc;
4797 if (!root->reloc_root)
4800 rc = root->fs_info->reloc_ctl;
4801 rc->merging_rsv_size += rc->nodes_relocated;
4803 if (rc->merge_reloc_tree) {
4804 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4806 rc->nodes_relocated, 1);
4811 new_root = pending->snap;
4812 reloc_root = create_reloc_root(trans, root->reloc_root,
4813 new_root->root_key.objectid);
4814 if (IS_ERR(reloc_root))
4815 return PTR_ERR(reloc_root);
4817 ret = __add_reloc_root(reloc_root);
4819 new_root->reloc_root = reloc_root;
4821 if (rc->create_reloc_tree)
4822 ret = clone_backref_node(trans, rc, root, reloc_root);