1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 2009 Oracle. All rights reserved.
6 #include <linux/sched.h>
7 #include <linux/pagemap.h>
8 #include <linux/writeback.h>
9 #include <linux/blkdev.h>
10 #include <linux/rbtree.h>
11 #include <linux/slab.h>
14 #include "transaction.h"
17 #include "btrfs_inode.h"
18 #include "async-thread.h"
19 #include "free-space-cache.h"
20 #include "inode-map.h"
22 #include "print-tree.h"
23 #include "delalloc-space.h"
24 #include "block-group.h"
27 * backref_node, mapping_node and tree_block start with this
30 struct rb_node rb_node;
35 * present a tree block in the backref cache
38 struct rb_node rb_node;
42 /* objectid of tree block owner, can be not uptodate */
44 /* link to pending, changed or detached list */
45 struct list_head list;
46 /* list of upper level blocks reference this block */
47 struct list_head upper;
48 /* list of child blocks in the cache */
49 struct list_head lower;
50 /* NULL if this node is not tree root */
51 struct btrfs_root *root;
52 /* extent buffer got by COW the block */
53 struct extent_buffer *eb;
54 /* level of tree block */
56 /* is the block in non-reference counted tree */
57 unsigned int cowonly:1;
58 /* 1 if no child node in the cache */
59 unsigned int lowest:1;
60 /* is the extent buffer locked */
61 unsigned int locked:1;
62 /* has the block been processed */
63 unsigned int processed:1;
64 /* have backrefs of this block been checked */
65 unsigned int checked:1;
67 * 1 if corresponding block has been cowed but some upper
68 * level block pointers may not point to the new location
70 unsigned int pending:1;
72 * 1 if the backref node isn't connected to any other
75 unsigned int detached:1;
79 * present a block pointer in the backref cache
82 struct list_head list[2];
83 struct backref_node *node[2];
88 #define RELOCATION_RESERVED_NODES 256
90 struct backref_cache {
91 /* red black tree of all backref nodes in the cache */
92 struct rb_root rb_root;
93 /* for passing backref nodes to btrfs_reloc_cow_block */
94 struct backref_node *path[BTRFS_MAX_LEVEL];
96 * list of blocks that have been cowed but some block
97 * pointers in upper level blocks may not reflect the
100 struct list_head pending[BTRFS_MAX_LEVEL];
101 /* list of backref nodes with no child node */
102 struct list_head leaves;
103 /* list of blocks that have been cowed in current transaction */
104 struct list_head changed;
105 /* list of detached backref node. */
106 struct list_head detached;
115 * map address of tree root to tree
117 struct mapping_node {
118 struct rb_node rb_node;
123 struct mapping_tree {
124 struct rb_root rb_root;
129 * present a tree block to process
132 struct rb_node rb_node;
134 struct btrfs_key key;
135 unsigned int level:8;
136 unsigned int key_ready:1;
139 #define MAX_EXTENTS 128
141 struct file_extent_cluster {
144 u64 boundary[MAX_EXTENTS];
148 struct reloc_control {
149 /* block group to relocate */
150 struct btrfs_block_group *block_group;
152 struct btrfs_root *extent_root;
153 /* inode for moving data */
154 struct inode *data_inode;
156 struct btrfs_block_rsv *block_rsv;
158 struct backref_cache backref_cache;
160 struct file_extent_cluster cluster;
161 /* tree blocks have been processed */
162 struct extent_io_tree processed_blocks;
163 /* map start of tree root to corresponding reloc tree */
164 struct mapping_tree reloc_root_tree;
165 /* list of reloc trees */
166 struct list_head reloc_roots;
167 /* list of subvolume trees that get relocated */
168 struct list_head dirty_subvol_roots;
169 /* size of metadata reservation for merging reloc trees */
170 u64 merging_rsv_size;
171 /* size of relocated tree nodes */
173 /* reserved size for block group relocation*/
179 unsigned int stage:8;
180 unsigned int create_reloc_tree:1;
181 unsigned int merge_reloc_tree:1;
182 unsigned int found_file_extent:1;
185 /* stages of data relocation */
186 #define MOVE_DATA_EXTENTS 0
187 #define UPDATE_DATA_PTRS 1
189 static void remove_backref_node(struct backref_cache *cache,
190 struct backref_node *node);
191 static void __mark_block_processed(struct reloc_control *rc,
192 struct backref_node *node);
194 static void mapping_tree_init(struct mapping_tree *tree)
196 tree->rb_root = RB_ROOT;
197 spin_lock_init(&tree->lock);
200 static void backref_cache_init(struct backref_cache *cache)
203 cache->rb_root = RB_ROOT;
204 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
205 INIT_LIST_HEAD(&cache->pending[i]);
206 INIT_LIST_HEAD(&cache->changed);
207 INIT_LIST_HEAD(&cache->detached);
208 INIT_LIST_HEAD(&cache->leaves);
211 static void backref_cache_cleanup(struct backref_cache *cache)
213 struct backref_node *node;
216 while (!list_empty(&cache->detached)) {
217 node = list_entry(cache->detached.next,
218 struct backref_node, list);
219 remove_backref_node(cache, node);
222 while (!list_empty(&cache->leaves)) {
223 node = list_entry(cache->leaves.next,
224 struct backref_node, lower);
225 remove_backref_node(cache, node);
228 cache->last_trans = 0;
230 for (i = 0; i < BTRFS_MAX_LEVEL; i++)
231 ASSERT(list_empty(&cache->pending[i]));
232 ASSERT(list_empty(&cache->changed));
233 ASSERT(list_empty(&cache->detached));
234 ASSERT(RB_EMPTY_ROOT(&cache->rb_root));
235 ASSERT(!cache->nr_nodes);
236 ASSERT(!cache->nr_edges);
239 static struct backref_node *alloc_backref_node(struct backref_cache *cache)
241 struct backref_node *node;
243 node = kzalloc(sizeof(*node), GFP_NOFS);
245 INIT_LIST_HEAD(&node->list);
246 INIT_LIST_HEAD(&node->upper);
247 INIT_LIST_HEAD(&node->lower);
248 RB_CLEAR_NODE(&node->rb_node);
254 static void free_backref_node(struct backref_cache *cache,
255 struct backref_node *node)
263 static struct backref_edge *alloc_backref_edge(struct backref_cache *cache)
265 struct backref_edge *edge;
267 edge = kzalloc(sizeof(*edge), GFP_NOFS);
273 static void free_backref_edge(struct backref_cache *cache,
274 struct backref_edge *edge)
282 static struct rb_node *tree_insert(struct rb_root *root, u64 bytenr,
283 struct rb_node *node)
285 struct rb_node **p = &root->rb_node;
286 struct rb_node *parent = NULL;
287 struct tree_entry *entry;
291 entry = rb_entry(parent, struct tree_entry, rb_node);
293 if (bytenr < entry->bytenr)
295 else if (bytenr > entry->bytenr)
301 rb_link_node(node, parent, p);
302 rb_insert_color(node, root);
306 static struct rb_node *tree_search(struct rb_root *root, u64 bytenr)
308 struct rb_node *n = root->rb_node;
309 struct tree_entry *entry;
312 entry = rb_entry(n, struct tree_entry, rb_node);
314 if (bytenr < entry->bytenr)
316 else if (bytenr > entry->bytenr)
324 static void backref_tree_panic(struct rb_node *rb_node, int errno, u64 bytenr)
327 struct btrfs_fs_info *fs_info = NULL;
328 struct backref_node *bnode = rb_entry(rb_node, struct backref_node,
331 fs_info = bnode->root->fs_info;
332 btrfs_panic(fs_info, errno,
333 "Inconsistency in backref cache found at offset %llu",
338 * walk up backref nodes until reach node presents tree root
340 static struct backref_node *walk_up_backref(struct backref_node *node,
341 struct backref_edge *edges[],
344 struct backref_edge *edge;
347 while (!list_empty(&node->upper)) {
348 edge = list_entry(node->upper.next,
349 struct backref_edge, list[LOWER]);
351 node = edge->node[UPPER];
353 BUG_ON(node->detached);
359 * walk down backref nodes to find start of next reference path
361 static struct backref_node *walk_down_backref(struct backref_edge *edges[],
364 struct backref_edge *edge;
365 struct backref_node *lower;
369 edge = edges[idx - 1];
370 lower = edge->node[LOWER];
371 if (list_is_last(&edge->list[LOWER], &lower->upper)) {
375 edge = list_entry(edge->list[LOWER].next,
376 struct backref_edge, list[LOWER]);
377 edges[idx - 1] = edge;
379 return edge->node[UPPER];
385 static void unlock_node_buffer(struct backref_node *node)
388 btrfs_tree_unlock(node->eb);
393 static void drop_node_buffer(struct backref_node *node)
396 unlock_node_buffer(node);
397 free_extent_buffer(node->eb);
402 static void drop_backref_node(struct backref_cache *tree,
403 struct backref_node *node)
405 BUG_ON(!list_empty(&node->upper));
407 drop_node_buffer(node);
408 list_del(&node->list);
409 list_del(&node->lower);
410 if (!RB_EMPTY_NODE(&node->rb_node))
411 rb_erase(&node->rb_node, &tree->rb_root);
412 free_backref_node(tree, node);
416 * remove a backref node from the backref cache
418 static void remove_backref_node(struct backref_cache *cache,
419 struct backref_node *node)
421 struct backref_node *upper;
422 struct backref_edge *edge;
427 BUG_ON(!node->lowest && !node->detached);
428 while (!list_empty(&node->upper)) {
429 edge = list_entry(node->upper.next, struct backref_edge,
431 upper = edge->node[UPPER];
432 list_del(&edge->list[LOWER]);
433 list_del(&edge->list[UPPER]);
434 free_backref_edge(cache, edge);
436 if (RB_EMPTY_NODE(&upper->rb_node)) {
437 BUG_ON(!list_empty(&node->upper));
438 drop_backref_node(cache, node);
444 * add the node to leaf node list if no other
445 * child block cached.
447 if (list_empty(&upper->lower)) {
448 list_add_tail(&upper->lower, &cache->leaves);
453 drop_backref_node(cache, node);
456 static void update_backref_node(struct backref_cache *cache,
457 struct backref_node *node, u64 bytenr)
459 struct rb_node *rb_node;
460 rb_erase(&node->rb_node, &cache->rb_root);
461 node->bytenr = bytenr;
462 rb_node = tree_insert(&cache->rb_root, node->bytenr, &node->rb_node);
464 backref_tree_panic(rb_node, -EEXIST, bytenr);
468 * update backref cache after a transaction commit
470 static int update_backref_cache(struct btrfs_trans_handle *trans,
471 struct backref_cache *cache)
473 struct backref_node *node;
476 if (cache->last_trans == 0) {
477 cache->last_trans = trans->transid;
481 if (cache->last_trans == trans->transid)
485 * detached nodes are used to avoid unnecessary backref
486 * lookup. transaction commit changes the extent tree.
487 * so the detached nodes are no longer useful.
489 while (!list_empty(&cache->detached)) {
490 node = list_entry(cache->detached.next,
491 struct backref_node, list);
492 remove_backref_node(cache, node);
495 while (!list_empty(&cache->changed)) {
496 node = list_entry(cache->changed.next,
497 struct backref_node, list);
498 list_del_init(&node->list);
499 BUG_ON(node->pending);
500 update_backref_node(cache, node, node->new_bytenr);
504 * some nodes can be left in the pending list if there were
505 * errors during processing the pending nodes.
507 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
508 list_for_each_entry(node, &cache->pending[level], list) {
509 BUG_ON(!node->pending);
510 if (node->bytenr == node->new_bytenr)
512 update_backref_node(cache, node, node->new_bytenr);
516 cache->last_trans = 0;
520 static bool reloc_root_is_dead(struct btrfs_root *root)
523 * Pair with set_bit/clear_bit in clean_dirty_subvols and
524 * btrfs_update_reloc_root. We need to see the updated bit before
525 * trying to access reloc_root
528 if (test_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state))
534 * Check if this subvolume tree has valid reloc tree.
536 * Reloc tree after swap is considered dead, thus not considered as valid.
537 * This is enough for most callers, as they don't distinguish dead reloc root
538 * from no reloc root. But should_ignore_root() below is a special case.
540 static bool have_reloc_root(struct btrfs_root *root)
542 if (reloc_root_is_dead(root))
544 if (!root->reloc_root)
549 static int should_ignore_root(struct btrfs_root *root)
551 struct btrfs_root *reloc_root;
553 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
556 /* This root has been merged with its reloc tree, we can ignore it */
557 if (reloc_root_is_dead(root))
560 reloc_root = root->reloc_root;
564 if (btrfs_root_last_snapshot(&reloc_root->root_item) ==
565 root->fs_info->running_transaction->transid - 1)
568 * if there is reloc tree and it was created in previous
569 * transaction backref lookup can find the reloc tree,
570 * so backref node for the fs tree root is useless for
576 * find reloc tree by address of tree root
578 static struct btrfs_root *find_reloc_root(struct reloc_control *rc,
581 struct rb_node *rb_node;
582 struct mapping_node *node;
583 struct btrfs_root *root = NULL;
585 spin_lock(&rc->reloc_root_tree.lock);
586 rb_node = tree_search(&rc->reloc_root_tree.rb_root, bytenr);
588 node = rb_entry(rb_node, struct mapping_node, rb_node);
589 root = (struct btrfs_root *)node->data;
591 spin_unlock(&rc->reloc_root_tree.lock);
595 static int is_cowonly_root(u64 root_objectid)
597 if (root_objectid == BTRFS_ROOT_TREE_OBJECTID ||
598 root_objectid == BTRFS_EXTENT_TREE_OBJECTID ||
599 root_objectid == BTRFS_CHUNK_TREE_OBJECTID ||
600 root_objectid == BTRFS_DEV_TREE_OBJECTID ||
601 root_objectid == BTRFS_TREE_LOG_OBJECTID ||
602 root_objectid == BTRFS_CSUM_TREE_OBJECTID ||
603 root_objectid == BTRFS_UUID_TREE_OBJECTID ||
604 root_objectid == BTRFS_QUOTA_TREE_OBJECTID ||
605 root_objectid == BTRFS_FREE_SPACE_TREE_OBJECTID)
610 static struct btrfs_root *read_fs_root(struct btrfs_fs_info *fs_info,
613 struct btrfs_key key;
615 key.objectid = root_objectid;
616 key.type = BTRFS_ROOT_ITEM_KEY;
617 if (is_cowonly_root(root_objectid))
620 key.offset = (u64)-1;
622 return btrfs_get_fs_root(fs_info, &key, false);
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 if (item_size < sizeof(*ei)) {
638 btrfs_print_v0_err(leaf->fs_info);
639 btrfs_handle_fs_error(leaf->fs_info, -EINVAL, NULL);
642 ei = btrfs_item_ptr(leaf, slot, struct btrfs_extent_item);
643 WARN_ON(!(btrfs_extent_flags(leaf, ei) &
644 BTRFS_EXTENT_FLAG_TREE_BLOCK));
646 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
647 item_size <= sizeof(*ei) + sizeof(*bi)) {
648 WARN_ON(item_size < sizeof(*ei) + sizeof(*bi));
651 if (key.type == BTRFS_METADATA_ITEM_KEY &&
652 item_size <= sizeof(*ei)) {
653 WARN_ON(item_size < sizeof(*ei));
657 if (key.type == BTRFS_EXTENT_ITEM_KEY) {
658 bi = (struct btrfs_tree_block_info *)(ei + 1);
659 *ptr = (unsigned long)(bi + 1);
661 *ptr = (unsigned long)(ei + 1);
663 *end = (unsigned long)ei + item_size;
668 * build backref tree for a given tree block. root of the backref tree
669 * corresponds the tree block, leaves of the backref tree correspond
670 * roots of b-trees that reference the tree block.
672 * the basic idea of this function is check backrefs of a given block
673 * to find upper level blocks that reference the block, and then check
674 * backrefs of these upper level blocks recursively. the recursion stop
675 * when tree root is reached or backrefs for the block is cached.
677 * NOTE: if we find backrefs for a block are cached, we know backrefs
678 * for all upper level blocks that directly/indirectly reference the
679 * block are also cached.
681 static noinline_for_stack
682 struct backref_node *build_backref_tree(struct reloc_control *rc,
683 struct btrfs_key *node_key,
684 int level, u64 bytenr)
686 struct backref_cache *cache = &rc->backref_cache;
687 struct btrfs_path *path1; /* For searching extent root */
688 struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */
689 struct extent_buffer *eb;
690 struct btrfs_root *root;
691 struct backref_node *cur;
692 struct backref_node *upper;
693 struct backref_node *lower;
694 struct backref_node *node = NULL;
695 struct backref_node *exist = NULL;
696 struct backref_edge *edge;
697 struct rb_node *rb_node;
698 struct btrfs_key key;
701 LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */
706 bool need_check = true;
708 path1 = btrfs_alloc_path();
709 path2 = btrfs_alloc_path();
710 if (!path1 || !path2) {
714 path1->reada = READA_FORWARD;
715 path2->reada = READA_FORWARD;
717 node = alloc_backref_node(cache);
723 node->bytenr = bytenr;
730 key.objectid = cur->bytenr;
731 key.type = BTRFS_METADATA_ITEM_KEY;
732 key.offset = (u64)-1;
734 path1->search_commit_root = 1;
735 path1->skip_locking = 1;
736 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path1,
743 ASSERT(path1->slots[0]);
747 WARN_ON(cur->checked);
748 if (!list_empty(&cur->upper)) {
750 * the backref was added previously when processing
751 * backref of type BTRFS_TREE_BLOCK_REF_KEY
753 ASSERT(list_is_singular(&cur->upper));
754 edge = list_entry(cur->upper.next, struct backref_edge,
756 ASSERT(list_empty(&edge->list[UPPER]));
757 exist = edge->node[UPPER];
759 * add the upper level block to pending list if we need
763 list_add_tail(&edge->list[UPPER], &list);
770 eb = path1->nodes[0];
773 if (path1->slots[0] >= btrfs_header_nritems(eb)) {
774 ret = btrfs_next_leaf(rc->extent_root, path1);
781 eb = path1->nodes[0];
784 btrfs_item_key_to_cpu(eb, &key, path1->slots[0]);
785 if (key.objectid != cur->bytenr) {
790 if (key.type == BTRFS_EXTENT_ITEM_KEY ||
791 key.type == BTRFS_METADATA_ITEM_KEY) {
792 ret = find_inline_backref(eb, path1->slots[0],
800 /* update key for inline back ref */
801 struct btrfs_extent_inline_ref *iref;
803 iref = (struct btrfs_extent_inline_ref *)ptr;
804 type = btrfs_get_extent_inline_ref_type(eb, iref,
805 BTRFS_REF_TYPE_BLOCK);
806 if (type == BTRFS_REF_TYPE_INVALID) {
811 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
813 WARN_ON(key.type != BTRFS_TREE_BLOCK_REF_KEY &&
814 key.type != BTRFS_SHARED_BLOCK_REF_KEY);
818 * Parent node found and matches current inline ref, no need to
819 * rebuild this node for this inline ref.
822 ((key.type == BTRFS_TREE_BLOCK_REF_KEY &&
823 exist->owner == key.offset) ||
824 (key.type == BTRFS_SHARED_BLOCK_REF_KEY &&
825 exist->bytenr == key.offset))) {
830 /* SHARED_BLOCK_REF means key.offset is the parent bytenr */
831 if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) {
832 if (key.objectid == key.offset) {
834 * Only root blocks of reloc trees use backref
835 * pointing to itself.
837 root = find_reloc_root(rc, cur->bytenr);
843 edge = alloc_backref_edge(cache);
848 rb_node = tree_search(&cache->rb_root, key.offset);
850 upper = alloc_backref_node(cache);
852 free_backref_edge(cache, edge);
856 upper->bytenr = key.offset;
857 upper->level = cur->level + 1;
859 * backrefs for the upper level block isn't
860 * cached, add the block to pending list
862 list_add_tail(&edge->list[UPPER], &list);
864 upper = rb_entry(rb_node, struct backref_node,
866 ASSERT(upper->checked);
867 INIT_LIST_HEAD(&edge->list[UPPER]);
869 list_add_tail(&edge->list[LOWER], &cur->upper);
870 edge->node[LOWER] = cur;
871 edge->node[UPPER] = upper;
874 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
876 btrfs_print_v0_err(rc->extent_root->fs_info);
877 btrfs_handle_fs_error(rc->extent_root->fs_info, err,
880 } else if (key.type != BTRFS_TREE_BLOCK_REF_KEY) {
885 * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset
886 * means the root objectid. We need to search the tree to get
889 root = read_fs_root(rc->extent_root->fs_info, key.offset);
895 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
898 if (btrfs_root_level(&root->root_item) == cur->level) {
900 ASSERT(btrfs_root_bytenr(&root->root_item) ==
902 if (should_ignore_root(root))
903 list_add(&cur->list, &useless);
909 level = cur->level + 1;
911 /* Search the tree to find parent blocks referring the block. */
912 path2->search_commit_root = 1;
913 path2->skip_locking = 1;
914 path2->lowest_level = level;
915 ret = btrfs_search_slot(NULL, root, node_key, path2, 0, 0);
916 path2->lowest_level = 0;
921 if (ret > 0 && path2->slots[level] > 0)
922 path2->slots[level]--;
924 eb = path2->nodes[level];
925 if (btrfs_node_blockptr(eb, path2->slots[level]) !=
927 btrfs_err(root->fs_info,
928 "couldn't find block (%llu) (level %d) in tree (%llu) with key (%llu %u %llu)",
929 cur->bytenr, level - 1,
930 root->root_key.objectid,
931 node_key->objectid, node_key->type,
939 /* Add all nodes and edges in the path */
940 for (; level < BTRFS_MAX_LEVEL; level++) {
941 if (!path2->nodes[level]) {
942 ASSERT(btrfs_root_bytenr(&root->root_item) ==
944 if (should_ignore_root(root))
945 list_add(&lower->list, &useless);
951 edge = alloc_backref_edge(cache);
957 eb = path2->nodes[level];
958 rb_node = tree_search(&cache->rb_root, eb->start);
960 upper = alloc_backref_node(cache);
962 free_backref_edge(cache, edge);
966 upper->bytenr = eb->start;
967 upper->owner = btrfs_header_owner(eb);
968 upper->level = lower->level + 1;
969 if (!test_bit(BTRFS_ROOT_REF_COWS,
974 * if we know the block isn't shared
975 * we can void checking its backrefs.
977 if (btrfs_block_can_be_shared(root, eb))
983 * add the block to pending list if we
984 * need check its backrefs, we only do this once
985 * while walking up a tree as we will catch
986 * anything else later on.
988 if (!upper->checked && need_check) {
990 list_add_tail(&edge->list[UPPER],
995 INIT_LIST_HEAD(&edge->list[UPPER]);
998 upper = rb_entry(rb_node, struct backref_node,
1000 ASSERT(upper->checked);
1001 INIT_LIST_HEAD(&edge->list[UPPER]);
1003 upper->owner = btrfs_header_owner(eb);
1005 list_add_tail(&edge->list[LOWER], &lower->upper);
1006 edge->node[LOWER] = lower;
1007 edge->node[UPPER] = upper;
1014 btrfs_release_path(path2);
1017 ptr += btrfs_extent_inline_ref_size(key.type);
1027 btrfs_release_path(path1);
1032 /* the pending list isn't empty, take the first block to process */
1033 if (!list_empty(&list)) {
1034 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1035 list_del_init(&edge->list[UPPER]);
1036 cur = edge->node[UPPER];
1041 * everything goes well, connect backref nodes and insert backref nodes
1044 ASSERT(node->checked);
1045 cowonly = node->cowonly;
1047 rb_node = tree_insert(&cache->rb_root, node->bytenr,
1050 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1051 list_add_tail(&node->lower, &cache->leaves);
1054 list_for_each_entry(edge, &node->upper, list[LOWER])
1055 list_add_tail(&edge->list[UPPER], &list);
1057 while (!list_empty(&list)) {
1058 edge = list_entry(list.next, struct backref_edge, list[UPPER]);
1059 list_del_init(&edge->list[UPPER]);
1060 upper = edge->node[UPPER];
1061 if (upper->detached) {
1062 list_del(&edge->list[LOWER]);
1063 lower = edge->node[LOWER];
1064 free_backref_edge(cache, edge);
1065 if (list_empty(&lower->upper))
1066 list_add(&lower->list, &useless);
1070 if (!RB_EMPTY_NODE(&upper->rb_node)) {
1071 if (upper->lowest) {
1072 list_del_init(&upper->lower);
1076 list_add_tail(&edge->list[UPPER], &upper->lower);
1080 if (!upper->checked) {
1082 * Still want to blow up for developers since this is a
1089 if (cowonly != upper->cowonly) {
1096 rb_node = tree_insert(&cache->rb_root, upper->bytenr,
1099 backref_tree_panic(rb_node, -EEXIST,
1103 list_add_tail(&edge->list[UPPER], &upper->lower);
1105 list_for_each_entry(edge, &upper->upper, list[LOWER])
1106 list_add_tail(&edge->list[UPPER], &list);
1109 * process useless backref nodes. backref nodes for tree leaves
1110 * are deleted from the cache. backref nodes for upper level
1111 * tree blocks are left in the cache to avoid unnecessary backref
1114 while (!list_empty(&useless)) {
1115 upper = list_entry(useless.next, struct backref_node, list);
1116 list_del_init(&upper->list);
1117 ASSERT(list_empty(&upper->upper));
1120 if (upper->lowest) {
1121 list_del_init(&upper->lower);
1124 while (!list_empty(&upper->lower)) {
1125 edge = list_entry(upper->lower.next,
1126 struct backref_edge, list[UPPER]);
1127 list_del(&edge->list[UPPER]);
1128 list_del(&edge->list[LOWER]);
1129 lower = edge->node[LOWER];
1130 free_backref_edge(cache, edge);
1132 if (list_empty(&lower->upper))
1133 list_add(&lower->list, &useless);
1135 __mark_block_processed(rc, upper);
1136 if (upper->level > 0) {
1137 list_add(&upper->list, &cache->detached);
1138 upper->detached = 1;
1140 rb_erase(&upper->rb_node, &cache->rb_root);
1141 free_backref_node(cache, upper);
1145 btrfs_free_path(path1);
1146 btrfs_free_path(path2);
1148 while (!list_empty(&useless)) {
1149 lower = list_entry(useless.next,
1150 struct backref_node, list);
1151 list_del_init(&lower->list);
1153 while (!list_empty(&list)) {
1154 edge = list_first_entry(&list, struct backref_edge,
1156 list_del(&edge->list[UPPER]);
1157 list_del(&edge->list[LOWER]);
1158 lower = edge->node[LOWER];
1159 upper = edge->node[UPPER];
1160 free_backref_edge(cache, edge);
1163 * Lower is no longer linked to any upper backref nodes
1164 * and isn't in the cache, we can free it ourselves.
1166 if (list_empty(&lower->upper) &&
1167 RB_EMPTY_NODE(&lower->rb_node))
1168 list_add(&lower->list, &useless);
1170 if (!RB_EMPTY_NODE(&upper->rb_node))
1173 /* Add this guy's upper edges to the list to process */
1174 list_for_each_entry(edge, &upper->upper, list[LOWER])
1175 list_add_tail(&edge->list[UPPER], &list);
1176 if (list_empty(&upper->upper))
1177 list_add(&upper->list, &useless);
1180 while (!list_empty(&useless)) {
1181 lower = list_entry(useless.next,
1182 struct backref_node, list);
1183 list_del_init(&lower->list);
1186 free_backref_node(cache, lower);
1189 free_backref_node(cache, node);
1190 return ERR_PTR(err);
1192 ASSERT(!node || !node->detached);
1197 * helper to add backref node for the newly created snapshot.
1198 * the backref node is created by cloning backref node that
1199 * corresponds to root of source tree
1201 static int clone_backref_node(struct btrfs_trans_handle *trans,
1202 struct reloc_control *rc,
1203 struct btrfs_root *src,
1204 struct btrfs_root *dest)
1206 struct btrfs_root *reloc_root = src->reloc_root;
1207 struct backref_cache *cache = &rc->backref_cache;
1208 struct backref_node *node = NULL;
1209 struct backref_node *new_node;
1210 struct backref_edge *edge;
1211 struct backref_edge *new_edge;
1212 struct rb_node *rb_node;
1214 if (cache->last_trans > 0)
1215 update_backref_cache(trans, cache);
1217 rb_node = tree_search(&cache->rb_root, src->commit_root->start);
1219 node = rb_entry(rb_node, struct backref_node, rb_node);
1223 BUG_ON(node->new_bytenr != reloc_root->node->start);
1227 rb_node = tree_search(&cache->rb_root,
1228 reloc_root->commit_root->start);
1230 node = rb_entry(rb_node, struct backref_node,
1232 BUG_ON(node->detached);
1239 new_node = alloc_backref_node(cache);
1243 new_node->bytenr = dest->node->start;
1244 new_node->level = node->level;
1245 new_node->lowest = node->lowest;
1246 new_node->checked = 1;
1247 new_node->root = dest;
1249 if (!node->lowest) {
1250 list_for_each_entry(edge, &node->lower, list[UPPER]) {
1251 new_edge = alloc_backref_edge(cache);
1255 new_edge->node[UPPER] = new_node;
1256 new_edge->node[LOWER] = edge->node[LOWER];
1257 list_add_tail(&new_edge->list[UPPER],
1261 list_add_tail(&new_node->lower, &cache->leaves);
1264 rb_node = tree_insert(&cache->rb_root, new_node->bytenr,
1265 &new_node->rb_node);
1267 backref_tree_panic(rb_node, -EEXIST, new_node->bytenr);
1269 if (!new_node->lowest) {
1270 list_for_each_entry(new_edge, &new_node->lower, list[UPPER]) {
1271 list_add_tail(&new_edge->list[LOWER],
1272 &new_edge->node[LOWER]->upper);
1277 while (!list_empty(&new_node->lower)) {
1278 new_edge = list_entry(new_node->lower.next,
1279 struct backref_edge, list[UPPER]);
1280 list_del(&new_edge->list[UPPER]);
1281 free_backref_edge(cache, new_edge);
1283 free_backref_node(cache, new_node);
1288 * helper to add 'address of tree root -> reloc tree' mapping
1290 static int __must_check __add_reloc_root(struct btrfs_root *root)
1292 struct btrfs_fs_info *fs_info = root->fs_info;
1293 struct rb_node *rb_node;
1294 struct mapping_node *node;
1295 struct reloc_control *rc = fs_info->reloc_ctl;
1297 node = kmalloc(sizeof(*node), GFP_NOFS);
1301 node->bytenr = root->node->start;
1304 spin_lock(&rc->reloc_root_tree.lock);
1305 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1306 node->bytenr, &node->rb_node);
1307 spin_unlock(&rc->reloc_root_tree.lock);
1309 btrfs_panic(fs_info, -EEXIST,
1310 "Duplicate root found for start=%llu while inserting into relocation tree",
1314 list_add_tail(&root->root_list, &rc->reloc_roots);
1319 * helper to delete the 'address of tree root -> reloc tree'
1322 static void __del_reloc_root(struct btrfs_root *root)
1324 struct btrfs_fs_info *fs_info = root->fs_info;
1325 struct rb_node *rb_node;
1326 struct mapping_node *node = NULL;
1327 struct reloc_control *rc = fs_info->reloc_ctl;
1329 if (rc && root->node) {
1330 spin_lock(&rc->reloc_root_tree.lock);
1331 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1334 node = rb_entry(rb_node, struct mapping_node, rb_node);
1335 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1337 spin_unlock(&rc->reloc_root_tree.lock);
1340 BUG_ON((struct btrfs_root *)node->data != root);
1343 spin_lock(&fs_info->trans_lock);
1344 list_del_init(&root->root_list);
1345 spin_unlock(&fs_info->trans_lock);
1350 * helper to update the 'address of tree root -> reloc tree'
1353 static int __update_reloc_root(struct btrfs_root *root, u64 new_bytenr)
1355 struct btrfs_fs_info *fs_info = root->fs_info;
1356 struct rb_node *rb_node;
1357 struct mapping_node *node = NULL;
1358 struct reloc_control *rc = fs_info->reloc_ctl;
1360 spin_lock(&rc->reloc_root_tree.lock);
1361 rb_node = tree_search(&rc->reloc_root_tree.rb_root,
1364 node = rb_entry(rb_node, struct mapping_node, rb_node);
1365 rb_erase(&node->rb_node, &rc->reloc_root_tree.rb_root);
1367 spin_unlock(&rc->reloc_root_tree.lock);
1371 BUG_ON((struct btrfs_root *)node->data != root);
1373 spin_lock(&rc->reloc_root_tree.lock);
1374 node->bytenr = new_bytenr;
1375 rb_node = tree_insert(&rc->reloc_root_tree.rb_root,
1376 node->bytenr, &node->rb_node);
1377 spin_unlock(&rc->reloc_root_tree.lock);
1379 backref_tree_panic(rb_node, -EEXIST, node->bytenr);
1383 static struct btrfs_root *create_reloc_root(struct btrfs_trans_handle *trans,
1384 struct btrfs_root *root, u64 objectid)
1386 struct btrfs_fs_info *fs_info = root->fs_info;
1387 struct btrfs_root *reloc_root;
1388 struct extent_buffer *eb;
1389 struct btrfs_root_item *root_item;
1390 struct btrfs_key root_key;
1393 root_item = kmalloc(sizeof(*root_item), GFP_NOFS);
1396 root_key.objectid = BTRFS_TREE_RELOC_OBJECTID;
1397 root_key.type = BTRFS_ROOT_ITEM_KEY;
1398 root_key.offset = objectid;
1400 if (root->root_key.objectid == objectid) {
1401 u64 commit_root_gen;
1403 /* called by btrfs_init_reloc_root */
1404 ret = btrfs_copy_root(trans, root, root->commit_root, &eb,
1405 BTRFS_TREE_RELOC_OBJECTID);
1408 * Set the last_snapshot field to the generation of the commit
1409 * root - like this ctree.c:btrfs_block_can_be_shared() behaves
1410 * correctly (returns true) when the relocation root is created
1411 * either inside the critical section of a transaction commit
1412 * (through transaction.c:qgroup_account_snapshot()) and when
1413 * it's created before the transaction commit is started.
1415 commit_root_gen = btrfs_header_generation(root->commit_root);
1416 btrfs_set_root_last_snapshot(&root->root_item, commit_root_gen);
1419 * called by btrfs_reloc_post_snapshot_hook.
1420 * the source tree is a reloc tree, all tree blocks
1421 * modified after it was created have RELOC flag
1422 * set in their headers. so it's OK to not update
1423 * the 'last_snapshot'.
1425 ret = btrfs_copy_root(trans, root, root->node, &eb,
1426 BTRFS_TREE_RELOC_OBJECTID);
1430 memcpy(root_item, &root->root_item, sizeof(*root_item));
1431 btrfs_set_root_bytenr(root_item, eb->start);
1432 btrfs_set_root_level(root_item, btrfs_header_level(eb));
1433 btrfs_set_root_generation(root_item, trans->transid);
1435 if (root->root_key.objectid == objectid) {
1436 btrfs_set_root_refs(root_item, 0);
1437 memset(&root_item->drop_progress, 0,
1438 sizeof(struct btrfs_disk_key));
1439 root_item->drop_level = 0;
1442 btrfs_tree_unlock(eb);
1443 free_extent_buffer(eb);
1445 ret = btrfs_insert_root(trans, fs_info->tree_root,
1446 &root_key, root_item);
1450 reloc_root = btrfs_read_fs_root(fs_info->tree_root, &root_key);
1451 BUG_ON(IS_ERR(reloc_root));
1452 reloc_root->last_trans = trans->transid;
1457 * create reloc tree for a given fs tree. reloc tree is just a
1458 * snapshot of the fs tree with special root objectid.
1460 int btrfs_init_reloc_root(struct btrfs_trans_handle *trans,
1461 struct btrfs_root *root)
1463 struct btrfs_fs_info *fs_info = root->fs_info;
1464 struct btrfs_root *reloc_root;
1465 struct reloc_control *rc = fs_info->reloc_ctl;
1466 struct btrfs_block_rsv *rsv;
1471 * The subvolume has reloc tree but the swap is finished, no need to
1472 * create/update the dead reloc tree
1474 if (reloc_root_is_dead(root))
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 (!have_reloc_root(root))
1516 reloc_root = root->reloc_root;
1517 root_item = &reloc_root->root_item;
1519 /* root->reloc_root will stay until current relocation finished */
1520 if (fs_info->reloc_ctl->merge_reloc_tree &&
1521 btrfs_root_refs(root_item) == 0) {
1522 set_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
1524 * Mark the tree as dead before we change reloc_root so
1525 * have_reloc_root will not touch it from now on.
1528 __del_reloc_root(reloc_root);
1531 if (reloc_root->commit_root != reloc_root->node) {
1532 btrfs_set_root_node(root_item, reloc_root->node);
1533 free_extent_buffer(reloc_root->commit_root);
1534 reloc_root->commit_root = btrfs_root_node(reloc_root);
1537 ret = btrfs_update_root(trans, fs_info->tree_root,
1538 &reloc_root->root_key, root_item);
1546 * helper to find first cached inode with inode number >= objectid
1549 static struct inode *find_next_inode(struct btrfs_root *root, u64 objectid)
1551 struct rb_node *node;
1552 struct rb_node *prev;
1553 struct btrfs_inode *entry;
1554 struct inode *inode;
1556 spin_lock(&root->inode_lock);
1558 node = root->inode_tree.rb_node;
1562 entry = rb_entry(node, struct btrfs_inode, rb_node);
1564 if (objectid < btrfs_ino(entry))
1565 node = node->rb_left;
1566 else if (objectid > btrfs_ino(entry))
1567 node = node->rb_right;
1573 entry = rb_entry(prev, struct btrfs_inode, rb_node);
1574 if (objectid <= btrfs_ino(entry)) {
1578 prev = rb_next(prev);
1582 entry = rb_entry(node, struct btrfs_inode, rb_node);
1583 inode = igrab(&entry->vfs_inode);
1585 spin_unlock(&root->inode_lock);
1589 objectid = btrfs_ino(entry) + 1;
1590 if (cond_resched_lock(&root->inode_lock))
1593 node = rb_next(node);
1595 spin_unlock(&root->inode_lock);
1599 static int in_block_group(u64 bytenr, struct btrfs_block_group *block_group)
1601 if (bytenr >= block_group->start &&
1602 bytenr < block_group->start + block_group->length)
1608 * get new location of data
1610 static int get_new_location(struct inode *reloc_inode, u64 *new_bytenr,
1611 u64 bytenr, u64 num_bytes)
1613 struct btrfs_root *root = BTRFS_I(reloc_inode)->root;
1614 struct btrfs_path *path;
1615 struct btrfs_file_extent_item *fi;
1616 struct extent_buffer *leaf;
1619 path = btrfs_alloc_path();
1623 bytenr -= BTRFS_I(reloc_inode)->index_cnt;
1624 ret = btrfs_lookup_file_extent(NULL, root, path,
1625 btrfs_ino(BTRFS_I(reloc_inode)), bytenr, 0);
1633 leaf = path->nodes[0];
1634 fi = btrfs_item_ptr(leaf, path->slots[0],
1635 struct btrfs_file_extent_item);
1637 BUG_ON(btrfs_file_extent_offset(leaf, fi) ||
1638 btrfs_file_extent_compression(leaf, fi) ||
1639 btrfs_file_extent_encryption(leaf, fi) ||
1640 btrfs_file_extent_other_encoding(leaf, fi));
1642 if (num_bytes != btrfs_file_extent_disk_num_bytes(leaf, fi)) {
1647 *new_bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1650 btrfs_free_path(path);
1655 * update file extent items in the tree leaf to point to
1656 * the new locations.
1658 static noinline_for_stack
1659 int replace_file_extents(struct btrfs_trans_handle *trans,
1660 struct reloc_control *rc,
1661 struct btrfs_root *root,
1662 struct extent_buffer *leaf)
1664 struct btrfs_fs_info *fs_info = root->fs_info;
1665 struct btrfs_key key;
1666 struct btrfs_file_extent_item *fi;
1667 struct inode *inode = NULL;
1679 if (rc->stage != UPDATE_DATA_PTRS)
1682 /* reloc trees always use full backref */
1683 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID)
1684 parent = leaf->start;
1688 nritems = btrfs_header_nritems(leaf);
1689 for (i = 0; i < nritems; i++) {
1690 struct btrfs_ref ref = { 0 };
1693 btrfs_item_key_to_cpu(leaf, &key, i);
1694 if (key.type != BTRFS_EXTENT_DATA_KEY)
1696 fi = btrfs_item_ptr(leaf, i, struct btrfs_file_extent_item);
1697 if (btrfs_file_extent_type(leaf, fi) ==
1698 BTRFS_FILE_EXTENT_INLINE)
1700 bytenr = btrfs_file_extent_disk_bytenr(leaf, fi);
1701 num_bytes = btrfs_file_extent_disk_num_bytes(leaf, fi);
1704 if (!in_block_group(bytenr, rc->block_group))
1708 * if we are modifying block in fs tree, wait for readpage
1709 * to complete and drop the extent cache
1711 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
1713 inode = find_next_inode(root, key.objectid);
1715 } else if (inode && btrfs_ino(BTRFS_I(inode)) < key.objectid) {
1716 btrfs_add_delayed_iput(inode);
1717 inode = find_next_inode(root, key.objectid);
1719 if (inode && btrfs_ino(BTRFS_I(inode)) == key.objectid) {
1721 btrfs_file_extent_num_bytes(leaf, fi);
1722 WARN_ON(!IS_ALIGNED(key.offset,
1723 fs_info->sectorsize));
1724 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
1726 ret = try_lock_extent(&BTRFS_I(inode)->io_tree,
1731 btrfs_drop_extent_cache(BTRFS_I(inode),
1732 key.offset, end, 1);
1733 unlock_extent(&BTRFS_I(inode)->io_tree,
1738 ret = get_new_location(rc->data_inode, &new_bytenr,
1742 * Don't have to abort since we've not changed anything
1743 * in the file extent yet.
1748 btrfs_set_file_extent_disk_bytenr(leaf, fi, new_bytenr);
1751 key.offset -= btrfs_file_extent_offset(leaf, fi);
1752 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1754 ref.real_root = root->root_key.objectid;
1755 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1756 key.objectid, key.offset);
1757 ret = btrfs_inc_extent_ref(trans, &ref);
1759 btrfs_abort_transaction(trans, ret);
1763 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, bytenr,
1765 ref.real_root = root->root_key.objectid;
1766 btrfs_init_data_ref(&ref, btrfs_header_owner(leaf),
1767 key.objectid, key.offset);
1768 ret = btrfs_free_extent(trans, &ref);
1770 btrfs_abort_transaction(trans, ret);
1775 btrfs_mark_buffer_dirty(leaf);
1777 btrfs_add_delayed_iput(inode);
1781 static noinline_for_stack
1782 int memcmp_node_keys(struct extent_buffer *eb, int slot,
1783 struct btrfs_path *path, int level)
1785 struct btrfs_disk_key key1;
1786 struct btrfs_disk_key key2;
1787 btrfs_node_key(eb, &key1, slot);
1788 btrfs_node_key(path->nodes[level], &key2, path->slots[level]);
1789 return memcmp(&key1, &key2, sizeof(key1));
1793 * try to replace tree blocks in fs tree with the new blocks
1794 * in reloc tree. tree blocks haven't been modified since the
1795 * reloc tree was create can be replaced.
1797 * if a block was replaced, level of the block + 1 is returned.
1798 * if no block got replaced, 0 is returned. if there are other
1799 * errors, a negative error number is returned.
1801 static noinline_for_stack
1802 int replace_path(struct btrfs_trans_handle *trans, struct reloc_control *rc,
1803 struct btrfs_root *dest, struct btrfs_root *src,
1804 struct btrfs_path *path, struct btrfs_key *next_key,
1805 int lowest_level, int max_level)
1807 struct btrfs_fs_info *fs_info = dest->fs_info;
1808 struct extent_buffer *eb;
1809 struct extent_buffer *parent;
1810 struct btrfs_ref ref = { 0 };
1811 struct btrfs_key key;
1823 BUG_ON(src->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
1824 BUG_ON(dest->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID);
1826 last_snapshot = btrfs_root_last_snapshot(&src->root_item);
1828 slot = path->slots[lowest_level];
1829 btrfs_node_key_to_cpu(path->nodes[lowest_level], &key, slot);
1831 eb = btrfs_lock_root_node(dest);
1832 btrfs_set_lock_blocking_write(eb);
1833 level = btrfs_header_level(eb);
1835 if (level < lowest_level) {
1836 btrfs_tree_unlock(eb);
1837 free_extent_buffer(eb);
1842 ret = btrfs_cow_block(trans, dest, eb, NULL, 0, &eb);
1845 btrfs_set_lock_blocking_write(eb);
1848 next_key->objectid = (u64)-1;
1849 next_key->type = (u8)-1;
1850 next_key->offset = (u64)-1;
1855 struct btrfs_key first_key;
1857 level = btrfs_header_level(parent);
1858 BUG_ON(level < lowest_level);
1860 ret = btrfs_bin_search(parent, &key, level, &slot);
1863 if (ret && slot > 0)
1866 if (next_key && slot + 1 < btrfs_header_nritems(parent))
1867 btrfs_node_key_to_cpu(parent, next_key, slot + 1);
1869 old_bytenr = btrfs_node_blockptr(parent, slot);
1870 blocksize = fs_info->nodesize;
1871 old_ptr_gen = btrfs_node_ptr_generation(parent, slot);
1872 btrfs_node_key_to_cpu(parent, &first_key, slot);
1874 if (level <= max_level) {
1875 eb = path->nodes[level];
1876 new_bytenr = btrfs_node_blockptr(eb,
1877 path->slots[level]);
1878 new_ptr_gen = btrfs_node_ptr_generation(eb,
1879 path->slots[level]);
1885 if (WARN_ON(new_bytenr > 0 && new_bytenr == old_bytenr)) {
1890 if (new_bytenr == 0 || old_ptr_gen > last_snapshot ||
1891 memcmp_node_keys(parent, slot, path, level)) {
1892 if (level <= lowest_level) {
1897 eb = read_tree_block(fs_info, old_bytenr, old_ptr_gen,
1898 level - 1, &first_key);
1902 } else if (!extent_buffer_uptodate(eb)) {
1904 free_extent_buffer(eb);
1907 btrfs_tree_lock(eb);
1909 ret = btrfs_cow_block(trans, dest, eb, parent,
1913 btrfs_set_lock_blocking_write(eb);
1915 btrfs_tree_unlock(parent);
1916 free_extent_buffer(parent);
1923 btrfs_tree_unlock(parent);
1924 free_extent_buffer(parent);
1929 btrfs_node_key_to_cpu(path->nodes[level], &key,
1930 path->slots[level]);
1931 btrfs_release_path(path);
1933 path->lowest_level = level;
1934 ret = btrfs_search_slot(trans, src, &key, path, 0, 1);
1935 path->lowest_level = 0;
1939 * Info qgroup to trace both subtrees.
1941 * We must trace both trees.
1942 * 1) Tree reloc subtree
1943 * If not traced, we will leak data numbers
1945 * If not traced, we will double count old data
1947 * We don't scan the subtree right now, but only record
1948 * the swapped tree blocks.
1949 * The real subtree rescan is delayed until we have new
1950 * CoW on the subtree root node before transaction commit.
1952 ret = btrfs_qgroup_add_swapped_blocks(trans, dest,
1953 rc->block_group, parent, slot,
1954 path->nodes[level], path->slots[level],
1959 * swap blocks in fs tree and reloc tree.
1961 btrfs_set_node_blockptr(parent, slot, new_bytenr);
1962 btrfs_set_node_ptr_generation(parent, slot, new_ptr_gen);
1963 btrfs_mark_buffer_dirty(parent);
1965 btrfs_set_node_blockptr(path->nodes[level],
1966 path->slots[level], old_bytenr);
1967 btrfs_set_node_ptr_generation(path->nodes[level],
1968 path->slots[level], old_ptr_gen);
1969 btrfs_mark_buffer_dirty(path->nodes[level]);
1971 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, old_bytenr,
1972 blocksize, path->nodes[level]->start);
1973 ref.skip_qgroup = true;
1974 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1975 ret = btrfs_inc_extent_ref(trans, &ref);
1977 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF, new_bytenr,
1979 ref.skip_qgroup = true;
1980 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1981 ret = btrfs_inc_extent_ref(trans, &ref);
1984 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, new_bytenr,
1985 blocksize, path->nodes[level]->start);
1986 btrfs_init_tree_ref(&ref, level - 1, src->root_key.objectid);
1987 ref.skip_qgroup = true;
1988 ret = btrfs_free_extent(trans, &ref);
1991 btrfs_init_generic_ref(&ref, BTRFS_DROP_DELAYED_REF, old_bytenr,
1993 btrfs_init_tree_ref(&ref, level - 1, dest->root_key.objectid);
1994 ref.skip_qgroup = true;
1995 ret = btrfs_free_extent(trans, &ref);
1998 btrfs_unlock_up_safe(path, 0);
2003 btrfs_tree_unlock(parent);
2004 free_extent_buffer(parent);
2009 * helper to find next relocated block in reloc tree
2011 static noinline_for_stack
2012 int walk_up_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2015 struct extent_buffer *eb;
2020 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2022 for (i = 0; i < *level; i++) {
2023 free_extent_buffer(path->nodes[i]);
2024 path->nodes[i] = NULL;
2027 for (i = *level; i < BTRFS_MAX_LEVEL && path->nodes[i]; i++) {
2028 eb = path->nodes[i];
2029 nritems = btrfs_header_nritems(eb);
2030 while (path->slots[i] + 1 < nritems) {
2032 if (btrfs_node_ptr_generation(eb, path->slots[i]) <=
2039 free_extent_buffer(path->nodes[i]);
2040 path->nodes[i] = NULL;
2046 * walk down reloc tree to find relocated block of lowest level
2048 static noinline_for_stack
2049 int walk_down_reloc_tree(struct btrfs_root *root, struct btrfs_path *path,
2052 struct btrfs_fs_info *fs_info = root->fs_info;
2053 struct extent_buffer *eb = NULL;
2060 last_snapshot = btrfs_root_last_snapshot(&root->root_item);
2062 for (i = *level; i > 0; i--) {
2063 struct btrfs_key first_key;
2065 eb = path->nodes[i];
2066 nritems = btrfs_header_nritems(eb);
2067 while (path->slots[i] < nritems) {
2068 ptr_gen = btrfs_node_ptr_generation(eb, path->slots[i]);
2069 if (ptr_gen > last_snapshot)
2073 if (path->slots[i] >= nritems) {
2084 bytenr = btrfs_node_blockptr(eb, path->slots[i]);
2085 btrfs_node_key_to_cpu(eb, &first_key, path->slots[i]);
2086 eb = read_tree_block(fs_info, bytenr, ptr_gen, i - 1,
2090 } else if (!extent_buffer_uptodate(eb)) {
2091 free_extent_buffer(eb);
2094 BUG_ON(btrfs_header_level(eb) != i - 1);
2095 path->nodes[i - 1] = eb;
2096 path->slots[i - 1] = 0;
2102 * invalidate extent cache for file extents whose key in range of
2103 * [min_key, max_key)
2105 static int invalidate_extent_cache(struct btrfs_root *root,
2106 struct btrfs_key *min_key,
2107 struct btrfs_key *max_key)
2109 struct btrfs_fs_info *fs_info = root->fs_info;
2110 struct inode *inode = NULL;
2115 objectid = min_key->objectid;
2120 if (objectid > max_key->objectid)
2123 inode = find_next_inode(root, objectid);
2126 ino = btrfs_ino(BTRFS_I(inode));
2128 if (ino > max_key->objectid) {
2134 if (!S_ISREG(inode->i_mode))
2137 if (unlikely(min_key->objectid == ino)) {
2138 if (min_key->type > BTRFS_EXTENT_DATA_KEY)
2140 if (min_key->type < BTRFS_EXTENT_DATA_KEY)
2143 start = min_key->offset;
2144 WARN_ON(!IS_ALIGNED(start, fs_info->sectorsize));
2150 if (unlikely(max_key->objectid == ino)) {
2151 if (max_key->type < BTRFS_EXTENT_DATA_KEY)
2153 if (max_key->type > BTRFS_EXTENT_DATA_KEY) {
2156 if (max_key->offset == 0)
2158 end = max_key->offset;
2159 WARN_ON(!IS_ALIGNED(end, fs_info->sectorsize));
2166 /* the lock_extent waits for readpage to complete */
2167 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
2168 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 1);
2169 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
2174 static int find_next_key(struct btrfs_path *path, int level,
2175 struct btrfs_key *key)
2178 while (level < BTRFS_MAX_LEVEL) {
2179 if (!path->nodes[level])
2181 if (path->slots[level] + 1 <
2182 btrfs_header_nritems(path->nodes[level])) {
2183 btrfs_node_key_to_cpu(path->nodes[level], key,
2184 path->slots[level] + 1);
2193 * Insert current subvolume into reloc_control::dirty_subvol_roots
2195 static void insert_dirty_subvol(struct btrfs_trans_handle *trans,
2196 struct reloc_control *rc,
2197 struct btrfs_root *root)
2199 struct btrfs_root *reloc_root = root->reloc_root;
2200 struct btrfs_root_item *reloc_root_item;
2202 /* @root must be a subvolume tree root with a valid reloc tree */
2203 ASSERT(root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID);
2206 reloc_root_item = &reloc_root->root_item;
2207 memset(&reloc_root_item->drop_progress, 0,
2208 sizeof(reloc_root_item->drop_progress));
2209 reloc_root_item->drop_level = 0;
2210 btrfs_set_root_refs(reloc_root_item, 0);
2211 btrfs_update_reloc_root(trans, root);
2213 if (list_empty(&root->reloc_dirty_list)) {
2214 btrfs_grab_fs_root(root);
2215 list_add_tail(&root->reloc_dirty_list, &rc->dirty_subvol_roots);
2219 static int clean_dirty_subvols(struct reloc_control *rc)
2221 struct btrfs_root *root;
2222 struct btrfs_root *next;
2226 list_for_each_entry_safe(root, next, &rc->dirty_subvol_roots,
2228 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID) {
2229 /* Merged subvolume, cleanup its reloc root */
2230 struct btrfs_root *reloc_root = root->reloc_root;
2232 list_del_init(&root->reloc_dirty_list);
2233 root->reloc_root = NULL;
2236 ret2 = btrfs_drop_snapshot(reloc_root, NULL, 0, 1);
2237 if (ret2 < 0 && !ret)
2241 * Need barrier to ensure clear_bit() only happens after
2242 * root->reloc_root = NULL. Pairs with have_reloc_root.
2245 clear_bit(BTRFS_ROOT_DEAD_RELOC_TREE, &root->state);
2246 btrfs_put_fs_root(root);
2248 /* Orphan reloc tree, just clean it up */
2249 ret2 = btrfs_drop_snapshot(root, NULL, 0, 1);
2250 if (ret2 < 0 && !ret)
2258 * merge the relocated tree blocks in reloc tree with corresponding
2261 static noinline_for_stack int merge_reloc_root(struct reloc_control *rc,
2262 struct btrfs_root *root)
2264 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2265 struct btrfs_key key;
2266 struct btrfs_key next_key;
2267 struct btrfs_trans_handle *trans = NULL;
2268 struct btrfs_root *reloc_root;
2269 struct btrfs_root_item *root_item;
2270 struct btrfs_path *path;
2271 struct extent_buffer *leaf;
2279 path = btrfs_alloc_path();
2282 path->reada = READA_FORWARD;
2284 reloc_root = root->reloc_root;
2285 root_item = &reloc_root->root_item;
2287 if (btrfs_disk_key_objectid(&root_item->drop_progress) == 0) {
2288 level = btrfs_root_level(root_item);
2289 atomic_inc(&reloc_root->node->refs);
2290 path->nodes[level] = reloc_root->node;
2291 path->slots[level] = 0;
2293 btrfs_disk_key_to_cpu(&key, &root_item->drop_progress);
2295 level = root_item->drop_level;
2297 path->lowest_level = level;
2298 ret = btrfs_search_slot(NULL, reloc_root, &key, path, 0, 0);
2299 path->lowest_level = 0;
2301 btrfs_free_path(path);
2305 btrfs_node_key_to_cpu(path->nodes[level], &next_key,
2306 path->slots[level]);
2307 WARN_ON(memcmp(&key, &next_key, sizeof(key)));
2309 btrfs_unlock_up_safe(path, 0);
2312 min_reserved = fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2313 memset(&next_key, 0, sizeof(next_key));
2316 ret = btrfs_block_rsv_refill(root, rc->block_rsv, min_reserved,
2317 BTRFS_RESERVE_FLUSH_ALL);
2322 trans = btrfs_start_transaction(root, 0);
2323 if (IS_ERR(trans)) {
2324 err = PTR_ERR(trans);
2328 trans->block_rsv = rc->block_rsv;
2333 ret = walk_down_reloc_tree(reloc_root, path, &level);
2341 if (!find_next_key(path, level, &key) &&
2342 btrfs_comp_cpu_keys(&next_key, &key) >= 0) {
2345 ret = replace_path(trans, rc, root, reloc_root, path,
2346 &next_key, level, max_level);
2355 btrfs_node_key_to_cpu(path->nodes[level], &key,
2356 path->slots[level]);
2360 ret = walk_up_reloc_tree(reloc_root, path, &level);
2366 * save the merging progress in the drop_progress.
2367 * this is OK since root refs == 1 in this case.
2369 btrfs_node_key(path->nodes[level], &root_item->drop_progress,
2370 path->slots[level]);
2371 root_item->drop_level = level;
2373 btrfs_end_transaction_throttle(trans);
2376 btrfs_btree_balance_dirty(fs_info);
2378 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2379 invalidate_extent_cache(root, &key, &next_key);
2383 * handle the case only one block in the fs tree need to be
2384 * relocated and the block is tree root.
2386 leaf = btrfs_lock_root_node(root);
2387 ret = btrfs_cow_block(trans, root, leaf, NULL, 0, &leaf);
2388 btrfs_tree_unlock(leaf);
2389 free_extent_buffer(leaf);
2393 btrfs_free_path(path);
2396 insert_dirty_subvol(trans, rc, root);
2399 btrfs_end_transaction_throttle(trans);
2401 btrfs_btree_balance_dirty(fs_info);
2403 if (replaced && rc->stage == UPDATE_DATA_PTRS)
2404 invalidate_extent_cache(root, &key, &next_key);
2409 static noinline_for_stack
2410 int prepare_to_merge(struct reloc_control *rc, int err)
2412 struct btrfs_root *root = rc->extent_root;
2413 struct btrfs_fs_info *fs_info = root->fs_info;
2414 struct btrfs_root *reloc_root;
2415 struct btrfs_trans_handle *trans;
2416 LIST_HEAD(reloc_roots);
2420 mutex_lock(&fs_info->reloc_mutex);
2421 rc->merging_rsv_size += fs_info->nodesize * (BTRFS_MAX_LEVEL - 1) * 2;
2422 rc->merging_rsv_size += rc->nodes_relocated * 2;
2423 mutex_unlock(&fs_info->reloc_mutex);
2427 num_bytes = rc->merging_rsv_size;
2428 ret = btrfs_block_rsv_add(root, rc->block_rsv, num_bytes,
2429 BTRFS_RESERVE_FLUSH_ALL);
2434 trans = btrfs_join_transaction(rc->extent_root);
2435 if (IS_ERR(trans)) {
2437 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2439 return PTR_ERR(trans);
2443 if (num_bytes != rc->merging_rsv_size) {
2444 btrfs_end_transaction(trans);
2445 btrfs_block_rsv_release(fs_info, rc->block_rsv,
2451 rc->merge_reloc_tree = 1;
2453 while (!list_empty(&rc->reloc_roots)) {
2454 reloc_root = list_entry(rc->reloc_roots.next,
2455 struct btrfs_root, root_list);
2456 list_del_init(&reloc_root->root_list);
2458 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2459 BUG_ON(IS_ERR(root));
2460 BUG_ON(root->reloc_root != reloc_root);
2463 * set reference count to 1, so btrfs_recover_relocation
2464 * knows it should resumes merging
2467 btrfs_set_root_refs(&reloc_root->root_item, 1);
2468 btrfs_update_reloc_root(trans, root);
2470 list_add(&reloc_root->root_list, &reloc_roots);
2473 list_splice(&reloc_roots, &rc->reloc_roots);
2476 btrfs_commit_transaction(trans);
2478 btrfs_end_transaction(trans);
2482 static noinline_for_stack
2483 void free_reloc_roots(struct list_head *list)
2485 struct btrfs_root *reloc_root;
2487 while (!list_empty(list)) {
2488 reloc_root = list_entry(list->next, struct btrfs_root,
2490 __del_reloc_root(reloc_root);
2491 free_extent_buffer(reloc_root->node);
2492 free_extent_buffer(reloc_root->commit_root);
2493 reloc_root->node = NULL;
2494 reloc_root->commit_root = NULL;
2498 static noinline_for_stack
2499 void merge_reloc_roots(struct reloc_control *rc)
2501 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2502 struct btrfs_root *root;
2503 struct btrfs_root *reloc_root;
2504 LIST_HEAD(reloc_roots);
2508 root = rc->extent_root;
2511 * this serializes us with btrfs_record_root_in_transaction,
2512 * we have to make sure nobody is in the middle of
2513 * adding their roots to the list while we are
2516 mutex_lock(&fs_info->reloc_mutex);
2517 list_splice_init(&rc->reloc_roots, &reloc_roots);
2518 mutex_unlock(&fs_info->reloc_mutex);
2520 while (!list_empty(&reloc_roots)) {
2522 reloc_root = list_entry(reloc_roots.next,
2523 struct btrfs_root, root_list);
2525 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
2526 root = read_fs_root(fs_info,
2527 reloc_root->root_key.offset);
2528 BUG_ON(IS_ERR(root));
2529 BUG_ON(root->reloc_root != reloc_root);
2531 ret = merge_reloc_root(rc, root);
2533 if (list_empty(&reloc_root->root_list))
2534 list_add_tail(&reloc_root->root_list,
2539 list_del_init(&reloc_root->root_list);
2540 /* Don't forget to queue this reloc root for cleanup */
2541 list_add_tail(&reloc_root->reloc_dirty_list,
2542 &rc->dirty_subvol_roots);
2552 btrfs_handle_fs_error(fs_info, ret, NULL);
2553 if (!list_empty(&reloc_roots))
2554 free_reloc_roots(&reloc_roots);
2556 /* new reloc root may be added */
2557 mutex_lock(&fs_info->reloc_mutex);
2558 list_splice_init(&rc->reloc_roots, &reloc_roots);
2559 mutex_unlock(&fs_info->reloc_mutex);
2560 if (!list_empty(&reloc_roots))
2561 free_reloc_roots(&reloc_roots);
2564 BUG_ON(!RB_EMPTY_ROOT(&rc->reloc_root_tree.rb_root));
2567 static void free_block_list(struct rb_root *blocks)
2569 struct tree_block *block;
2570 struct rb_node *rb_node;
2571 while ((rb_node = rb_first(blocks))) {
2572 block = rb_entry(rb_node, struct tree_block, rb_node);
2573 rb_erase(rb_node, blocks);
2578 static int record_reloc_root_in_trans(struct btrfs_trans_handle *trans,
2579 struct btrfs_root *reloc_root)
2581 struct btrfs_fs_info *fs_info = reloc_root->fs_info;
2582 struct btrfs_root *root;
2584 if (reloc_root->last_trans == trans->transid)
2587 root = read_fs_root(fs_info, reloc_root->root_key.offset);
2588 BUG_ON(IS_ERR(root));
2589 BUG_ON(root->reloc_root != reloc_root);
2591 return btrfs_record_root_in_trans(trans, root);
2594 static noinline_for_stack
2595 struct btrfs_root *select_reloc_root(struct btrfs_trans_handle *trans,
2596 struct reloc_control *rc,
2597 struct backref_node *node,
2598 struct backref_edge *edges[])
2600 struct backref_node *next;
2601 struct btrfs_root *root;
2607 next = walk_up_backref(next, edges, &index);
2610 BUG_ON(!test_bit(BTRFS_ROOT_REF_COWS, &root->state));
2612 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
2613 record_reloc_root_in_trans(trans, root);
2617 btrfs_record_root_in_trans(trans, root);
2618 root = root->reloc_root;
2620 if (next->new_bytenr != root->node->start) {
2621 BUG_ON(next->new_bytenr);
2622 BUG_ON(!list_empty(&next->list));
2623 next->new_bytenr = root->node->start;
2625 list_add_tail(&next->list,
2626 &rc->backref_cache.changed);
2627 __mark_block_processed(rc, next);
2633 next = walk_down_backref(edges, &index);
2634 if (!next || next->level <= node->level)
2641 /* setup backref node path for btrfs_reloc_cow_block */
2643 rc->backref_cache.path[next->level] = next;
2646 next = edges[index]->node[UPPER];
2652 * select a tree root for relocation. return NULL if the block
2653 * is reference counted. we should use do_relocation() in this
2654 * case. return a tree root pointer if the block isn't reference
2655 * counted. return -ENOENT if the block is root of reloc tree.
2657 static noinline_for_stack
2658 struct btrfs_root *select_one_root(struct backref_node *node)
2660 struct backref_node *next;
2661 struct btrfs_root *root;
2662 struct btrfs_root *fs_root = NULL;
2663 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2669 next = walk_up_backref(next, edges, &index);
2673 /* no other choice for non-references counted tree */
2674 if (!test_bit(BTRFS_ROOT_REF_COWS, &root->state))
2677 if (root->root_key.objectid != BTRFS_TREE_RELOC_OBJECTID)
2683 next = walk_down_backref(edges, &index);
2684 if (!next || next->level <= node->level)
2689 return ERR_PTR(-ENOENT);
2693 static noinline_for_stack
2694 u64 calcu_metadata_size(struct reloc_control *rc,
2695 struct backref_node *node, int reserve)
2697 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2698 struct backref_node *next = node;
2699 struct backref_edge *edge;
2700 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2704 BUG_ON(reserve && node->processed);
2709 if (next->processed && (reserve || next != node))
2712 num_bytes += fs_info->nodesize;
2714 if (list_empty(&next->upper))
2717 edge = list_entry(next->upper.next,
2718 struct backref_edge, list[LOWER]);
2719 edges[index++] = edge;
2720 next = edge->node[UPPER];
2722 next = walk_down_backref(edges, &index);
2727 static int reserve_metadata_space(struct btrfs_trans_handle *trans,
2728 struct reloc_control *rc,
2729 struct backref_node *node)
2731 struct btrfs_root *root = rc->extent_root;
2732 struct btrfs_fs_info *fs_info = root->fs_info;
2737 num_bytes = calcu_metadata_size(rc, node, 1) * 2;
2739 trans->block_rsv = rc->block_rsv;
2740 rc->reserved_bytes += num_bytes;
2743 * We are under a transaction here so we can only do limited flushing.
2744 * If we get an enospc just kick back -EAGAIN so we know to drop the
2745 * transaction and try to refill when we can flush all the things.
2747 ret = btrfs_block_rsv_refill(root, rc->block_rsv, num_bytes,
2748 BTRFS_RESERVE_FLUSH_LIMIT);
2750 tmp = fs_info->nodesize * RELOCATION_RESERVED_NODES;
2751 while (tmp <= rc->reserved_bytes)
2754 * only one thread can access block_rsv at this point,
2755 * so we don't need hold lock to protect block_rsv.
2756 * we expand more reservation size here to allow enough
2757 * space for relocation and we will return earlier in
2760 rc->block_rsv->size = tmp + fs_info->nodesize *
2761 RELOCATION_RESERVED_NODES;
2769 * relocate a block tree, and then update pointers in upper level
2770 * blocks that reference the block to point to the new location.
2772 * if called by link_to_upper, the block has already been relocated.
2773 * in that case this function just updates pointers.
2775 static int do_relocation(struct btrfs_trans_handle *trans,
2776 struct reloc_control *rc,
2777 struct backref_node *node,
2778 struct btrfs_key *key,
2779 struct btrfs_path *path, int lowest)
2781 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
2782 struct backref_node *upper;
2783 struct backref_edge *edge;
2784 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
2785 struct btrfs_root *root;
2786 struct extent_buffer *eb;
2794 BUG_ON(lowest && node->eb);
2796 path->lowest_level = node->level + 1;
2797 rc->backref_cache.path[node->level] = node;
2798 list_for_each_entry(edge, &node->upper, list[LOWER]) {
2799 struct btrfs_key first_key;
2800 struct btrfs_ref ref = { 0 };
2804 upper = edge->node[UPPER];
2805 root = select_reloc_root(trans, rc, upper, edges);
2808 if (upper->eb && !upper->locked) {
2810 ret = btrfs_bin_search(upper->eb, key,
2811 upper->level, &slot);
2817 bytenr = btrfs_node_blockptr(upper->eb, slot);
2818 if (node->eb->start == bytenr)
2821 drop_node_buffer(upper);
2825 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
2832 btrfs_release_path(path);
2837 upper->eb = path->nodes[upper->level];
2838 path->nodes[upper->level] = NULL;
2840 BUG_ON(upper->eb != path->nodes[upper->level]);
2844 path->locks[upper->level] = 0;
2846 slot = path->slots[upper->level];
2847 btrfs_release_path(path);
2849 ret = btrfs_bin_search(upper->eb, key, upper->level,
2858 bytenr = btrfs_node_blockptr(upper->eb, slot);
2860 if (bytenr != node->bytenr) {
2861 btrfs_err(root->fs_info,
2862 "lowest leaf/node mismatch: bytenr %llu node->bytenr %llu slot %d upper %llu",
2863 bytenr, node->bytenr, slot,
2869 if (node->eb->start == bytenr)
2873 blocksize = root->fs_info->nodesize;
2874 generation = btrfs_node_ptr_generation(upper->eb, slot);
2875 btrfs_node_key_to_cpu(upper->eb, &first_key, slot);
2876 eb = read_tree_block(fs_info, bytenr, generation,
2877 upper->level - 1, &first_key);
2881 } else if (!extent_buffer_uptodate(eb)) {
2882 free_extent_buffer(eb);
2886 btrfs_tree_lock(eb);
2887 btrfs_set_lock_blocking_write(eb);
2890 ret = btrfs_cow_block(trans, root, eb, upper->eb,
2892 btrfs_tree_unlock(eb);
2893 free_extent_buffer(eb);
2898 BUG_ON(node->eb != eb);
2900 btrfs_set_node_blockptr(upper->eb, slot,
2902 btrfs_set_node_ptr_generation(upper->eb, slot,
2904 btrfs_mark_buffer_dirty(upper->eb);
2906 btrfs_init_generic_ref(&ref, BTRFS_ADD_DELAYED_REF,
2907 node->eb->start, blocksize,
2909 ref.real_root = root->root_key.objectid;
2910 btrfs_init_tree_ref(&ref, node->level,
2911 btrfs_header_owner(upper->eb));
2912 ret = btrfs_inc_extent_ref(trans, &ref);
2915 ret = btrfs_drop_subtree(trans, root, eb, upper->eb);
2919 if (!upper->pending)
2920 drop_node_buffer(upper);
2922 unlock_node_buffer(upper);
2927 if (!err && node->pending) {
2928 drop_node_buffer(node);
2929 list_move_tail(&node->list, &rc->backref_cache.changed);
2933 path->lowest_level = 0;
2934 BUG_ON(err == -ENOSPC);
2938 static int link_to_upper(struct btrfs_trans_handle *trans,
2939 struct reloc_control *rc,
2940 struct backref_node *node,
2941 struct btrfs_path *path)
2943 struct btrfs_key key;
2945 btrfs_node_key_to_cpu(node->eb, &key, 0);
2946 return do_relocation(trans, rc, node, &key, path, 0);
2949 static int finish_pending_nodes(struct btrfs_trans_handle *trans,
2950 struct reloc_control *rc,
2951 struct btrfs_path *path, int err)
2954 struct backref_cache *cache = &rc->backref_cache;
2955 struct backref_node *node;
2959 for (level = 0; level < BTRFS_MAX_LEVEL; level++) {
2960 while (!list_empty(&cache->pending[level])) {
2961 node = list_entry(cache->pending[level].next,
2962 struct backref_node, list);
2963 list_move_tail(&node->list, &list);
2964 BUG_ON(!node->pending);
2967 ret = link_to_upper(trans, rc, node, path);
2972 list_splice_init(&list, &cache->pending[level]);
2977 static void mark_block_processed(struct reloc_control *rc,
2978 u64 bytenr, u32 blocksize)
2980 set_extent_bits(&rc->processed_blocks, bytenr, bytenr + blocksize - 1,
2984 static void __mark_block_processed(struct reloc_control *rc,
2985 struct backref_node *node)
2988 if (node->level == 0 ||
2989 in_block_group(node->bytenr, rc->block_group)) {
2990 blocksize = rc->extent_root->fs_info->nodesize;
2991 mark_block_processed(rc, node->bytenr, blocksize);
2993 node->processed = 1;
2997 * mark a block and all blocks directly/indirectly reference the block
3000 static void update_processed_blocks(struct reloc_control *rc,
3001 struct backref_node *node)
3003 struct backref_node *next = node;
3004 struct backref_edge *edge;
3005 struct backref_edge *edges[BTRFS_MAX_LEVEL - 1];
3011 if (next->processed)
3014 __mark_block_processed(rc, next);
3016 if (list_empty(&next->upper))
3019 edge = list_entry(next->upper.next,
3020 struct backref_edge, list[LOWER]);
3021 edges[index++] = edge;
3022 next = edge->node[UPPER];
3024 next = walk_down_backref(edges, &index);
3028 static int tree_block_processed(u64 bytenr, struct reloc_control *rc)
3030 u32 blocksize = rc->extent_root->fs_info->nodesize;
3032 if (test_range_bit(&rc->processed_blocks, bytenr,
3033 bytenr + blocksize - 1, EXTENT_DIRTY, 1, NULL))
3038 static int get_tree_block_key(struct btrfs_fs_info *fs_info,
3039 struct tree_block *block)
3041 struct extent_buffer *eb;
3043 BUG_ON(block->key_ready);
3044 eb = read_tree_block(fs_info, block->bytenr, block->key.offset,
3045 block->level, NULL);
3048 } else if (!extent_buffer_uptodate(eb)) {
3049 free_extent_buffer(eb);
3052 if (block->level == 0)
3053 btrfs_item_key_to_cpu(eb, &block->key, 0);
3055 btrfs_node_key_to_cpu(eb, &block->key, 0);
3056 free_extent_buffer(eb);
3057 block->key_ready = 1;
3062 * helper function to relocate a tree block
3064 static int relocate_tree_block(struct btrfs_trans_handle *trans,
3065 struct reloc_control *rc,
3066 struct backref_node *node,
3067 struct btrfs_key *key,
3068 struct btrfs_path *path)
3070 struct btrfs_root *root;
3076 BUG_ON(node->processed);
3077 root = select_one_root(node);
3078 if (root == ERR_PTR(-ENOENT)) {
3079 update_processed_blocks(rc, node);
3083 if (!root || test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3084 ret = reserve_metadata_space(trans, rc, node);
3090 if (test_bit(BTRFS_ROOT_REF_COWS, &root->state)) {
3091 BUG_ON(node->new_bytenr);
3092 BUG_ON(!list_empty(&node->list));
3093 btrfs_record_root_in_trans(trans, root);
3094 root = root->reloc_root;
3095 node->new_bytenr = root->node->start;
3097 list_add_tail(&node->list, &rc->backref_cache.changed);
3099 path->lowest_level = node->level;
3100 ret = btrfs_search_slot(trans, root, key, path, 0, 1);
3101 btrfs_release_path(path);
3106 update_processed_blocks(rc, node);
3108 ret = do_relocation(trans, rc, node, key, path, 1);
3111 if (ret || node->level == 0 || node->cowonly)
3112 remove_backref_node(&rc->backref_cache, node);
3117 * relocate a list of blocks
3119 static noinline_for_stack
3120 int relocate_tree_blocks(struct btrfs_trans_handle *trans,
3121 struct reloc_control *rc, struct rb_root *blocks)
3123 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3124 struct backref_node *node;
3125 struct btrfs_path *path;
3126 struct tree_block *block;
3127 struct tree_block *next;
3131 path = btrfs_alloc_path();
3134 goto out_free_blocks;
3137 /* Kick in readahead for tree blocks with missing keys */
3138 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3139 if (!block->key_ready)
3140 readahead_tree_block(fs_info, block->bytenr);
3143 /* Get first keys */
3144 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3145 if (!block->key_ready) {
3146 err = get_tree_block_key(fs_info, block);
3152 /* Do tree relocation */
3153 rbtree_postorder_for_each_entry_safe(block, next, blocks, rb_node) {
3154 node = build_backref_tree(rc, &block->key,
3155 block->level, block->bytenr);
3157 err = PTR_ERR(node);
3161 ret = relocate_tree_block(trans, rc, node, &block->key,
3164 if (ret != -EAGAIN || &block->rb_node == rb_first(blocks))
3170 err = finish_pending_nodes(trans, rc, path, err);
3173 btrfs_free_path(path);
3175 free_block_list(blocks);
3179 static noinline_for_stack
3180 int prealloc_file_extent_cluster(struct inode *inode,
3181 struct file_extent_cluster *cluster)
3186 u64 offset = BTRFS_I(inode)->index_cnt;
3190 u64 prealloc_start = cluster->start - offset;
3191 u64 prealloc_end = cluster->end - offset;
3193 struct extent_changeset *data_reserved = NULL;
3195 BUG_ON(cluster->start != cluster->boundary[0]);
3198 ret = btrfs_check_data_free_space(inode, &data_reserved, prealloc_start,
3199 prealloc_end + 1 - prealloc_start);
3203 cur_offset = prealloc_start;
3204 while (nr < cluster->nr) {
3205 start = cluster->boundary[nr] - offset;
3206 if (nr + 1 < cluster->nr)
3207 end = cluster->boundary[nr + 1] - 1 - offset;
3209 end = cluster->end - offset;
3211 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3212 num_bytes = end + 1 - start;
3213 if (cur_offset < start)
3214 btrfs_free_reserved_data_space(inode, data_reserved,
3215 cur_offset, start - cur_offset);
3216 ret = btrfs_prealloc_file_range(inode, 0, start,
3217 num_bytes, num_bytes,
3218 end + 1, &alloc_hint);
3219 cur_offset = end + 1;
3220 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3225 if (cur_offset < prealloc_end)
3226 btrfs_free_reserved_data_space(inode, data_reserved,
3227 cur_offset, prealloc_end + 1 - cur_offset);
3229 inode_unlock(inode);
3230 extent_changeset_free(data_reserved);
3234 static noinline_for_stack
3235 int setup_extent_mapping(struct inode *inode, u64 start, u64 end,
3238 struct extent_map_tree *em_tree = &BTRFS_I(inode)->extent_tree;
3239 struct extent_map *em;
3242 em = alloc_extent_map();
3247 em->len = end + 1 - start;
3248 em->block_len = em->len;
3249 em->block_start = block_start;
3250 set_bit(EXTENT_FLAG_PINNED, &em->flags);
3252 lock_extent(&BTRFS_I(inode)->io_tree, start, end);
3254 write_lock(&em_tree->lock);
3255 ret = add_extent_mapping(em_tree, em, 0);
3256 write_unlock(&em_tree->lock);
3257 if (ret != -EEXIST) {
3258 free_extent_map(em);
3261 btrfs_drop_extent_cache(BTRFS_I(inode), start, end, 0);
3263 unlock_extent(&BTRFS_I(inode)->io_tree, start, end);
3267 static int relocate_file_extent_cluster(struct inode *inode,
3268 struct file_extent_cluster *cluster)
3270 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
3273 u64 offset = BTRFS_I(inode)->index_cnt;
3274 unsigned long index;
3275 unsigned long last_index;
3277 struct file_ra_state *ra;
3278 gfp_t mask = btrfs_alloc_write_mask(inode->i_mapping);
3285 ra = kzalloc(sizeof(*ra), GFP_NOFS);
3289 ret = prealloc_file_extent_cluster(inode, cluster);
3293 file_ra_state_init(ra, inode->i_mapping);
3295 ret = setup_extent_mapping(inode, cluster->start - offset,
3296 cluster->end - offset, cluster->start);
3300 index = (cluster->start - offset) >> PAGE_SHIFT;
3301 last_index = (cluster->end - offset) >> PAGE_SHIFT;
3302 while (index <= last_index) {
3303 ret = btrfs_delalloc_reserve_metadata(BTRFS_I(inode),
3308 page = find_lock_page(inode->i_mapping, index);
3310 page_cache_sync_readahead(inode->i_mapping,
3312 last_index + 1 - index);
3313 page = find_or_create_page(inode->i_mapping, index,
3316 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3318 btrfs_delalloc_release_extents(BTRFS_I(inode),
3325 if (PageReadahead(page)) {
3326 page_cache_async_readahead(inode->i_mapping,
3327 ra, NULL, page, index,
3328 last_index + 1 - index);
3331 if (!PageUptodate(page)) {
3332 btrfs_readpage(NULL, page);
3334 if (!PageUptodate(page)) {
3337 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3339 btrfs_delalloc_release_extents(BTRFS_I(inode),
3346 page_start = page_offset(page);
3347 page_end = page_start + PAGE_SIZE - 1;
3349 lock_extent(&BTRFS_I(inode)->io_tree, page_start, page_end);
3351 set_page_extent_mapped(page);
3353 if (nr < cluster->nr &&
3354 page_start + offset == cluster->boundary[nr]) {
3355 set_extent_bits(&BTRFS_I(inode)->io_tree,
3356 page_start, page_end,
3361 ret = btrfs_set_extent_delalloc(inode, page_start, page_end, 0,
3366 btrfs_delalloc_release_metadata(BTRFS_I(inode),
3368 btrfs_delalloc_release_extents(BTRFS_I(inode),
3371 clear_extent_bits(&BTRFS_I(inode)->io_tree,
3372 page_start, page_end,
3373 EXTENT_LOCKED | EXTENT_BOUNDARY);
3377 set_page_dirty(page);
3379 unlock_extent(&BTRFS_I(inode)->io_tree,
3380 page_start, page_end);
3385 btrfs_delalloc_release_extents(BTRFS_I(inode), PAGE_SIZE);
3386 balance_dirty_pages_ratelimited(inode->i_mapping);
3387 btrfs_throttle(fs_info);
3389 WARN_ON(nr != cluster->nr);
3395 static noinline_for_stack
3396 int relocate_data_extent(struct inode *inode, struct btrfs_key *extent_key,
3397 struct file_extent_cluster *cluster)
3401 if (cluster->nr > 0 && extent_key->objectid != cluster->end + 1) {
3402 ret = relocate_file_extent_cluster(inode, cluster);
3409 cluster->start = extent_key->objectid;
3411 BUG_ON(cluster->nr >= MAX_EXTENTS);
3412 cluster->end = extent_key->objectid + extent_key->offset - 1;
3413 cluster->boundary[cluster->nr] = extent_key->objectid;
3416 if (cluster->nr >= MAX_EXTENTS) {
3417 ret = relocate_file_extent_cluster(inode, cluster);
3426 * helper to add a tree block to the list.
3427 * the major work is getting the generation and level of the block
3429 static int add_tree_block(struct reloc_control *rc,
3430 struct btrfs_key *extent_key,
3431 struct btrfs_path *path,
3432 struct rb_root *blocks)
3434 struct extent_buffer *eb;
3435 struct btrfs_extent_item *ei;
3436 struct btrfs_tree_block_info *bi;
3437 struct tree_block *block;
3438 struct rb_node *rb_node;
3443 eb = path->nodes[0];
3444 item_size = btrfs_item_size_nr(eb, path->slots[0]);
3446 if (extent_key->type == BTRFS_METADATA_ITEM_KEY ||
3447 item_size >= sizeof(*ei) + sizeof(*bi)) {
3448 ei = btrfs_item_ptr(eb, path->slots[0],
3449 struct btrfs_extent_item);
3450 if (extent_key->type == BTRFS_EXTENT_ITEM_KEY) {
3451 bi = (struct btrfs_tree_block_info *)(ei + 1);
3452 level = btrfs_tree_block_level(eb, bi);
3454 level = (int)extent_key->offset;
3456 generation = btrfs_extent_generation(eb, ei);
3457 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
3458 btrfs_print_v0_err(eb->fs_info);
3459 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3465 btrfs_release_path(path);
3467 BUG_ON(level == -1);
3469 block = kmalloc(sizeof(*block), GFP_NOFS);
3473 block->bytenr = extent_key->objectid;
3474 block->key.objectid = rc->extent_root->fs_info->nodesize;
3475 block->key.offset = generation;
3476 block->level = level;
3477 block->key_ready = 0;
3479 rb_node = tree_insert(blocks, block->bytenr, &block->rb_node);
3481 backref_tree_panic(rb_node, -EEXIST, block->bytenr);
3487 * helper to add tree blocks for backref of type BTRFS_SHARED_DATA_REF_KEY
3489 static int __add_tree_block(struct reloc_control *rc,
3490 u64 bytenr, u32 blocksize,
3491 struct rb_root *blocks)
3493 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3494 struct btrfs_path *path;
3495 struct btrfs_key key;
3497 bool skinny = btrfs_fs_incompat(fs_info, SKINNY_METADATA);
3499 if (tree_block_processed(bytenr, rc))
3502 if (tree_search(blocks, bytenr))
3505 path = btrfs_alloc_path();
3509 key.objectid = bytenr;
3511 key.type = BTRFS_METADATA_ITEM_KEY;
3512 key.offset = (u64)-1;
3514 key.type = BTRFS_EXTENT_ITEM_KEY;
3515 key.offset = blocksize;
3518 path->search_commit_root = 1;
3519 path->skip_locking = 1;
3520 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path, 0, 0);
3524 if (ret > 0 && skinny) {
3525 if (path->slots[0]) {
3527 btrfs_item_key_to_cpu(path->nodes[0], &key,
3529 if (key.objectid == bytenr &&
3530 (key.type == BTRFS_METADATA_ITEM_KEY ||
3531 (key.type == BTRFS_EXTENT_ITEM_KEY &&
3532 key.offset == blocksize)))
3538 btrfs_release_path(path);
3544 btrfs_print_leaf(path->nodes[0]);
3546 "tree block extent item (%llu) is not found in extent tree",
3553 ret = add_tree_block(rc, &key, path, blocks);
3555 btrfs_free_path(path);
3560 * helper to check if the block use full backrefs for pointers in it
3562 static int block_use_full_backref(struct reloc_control *rc,
3563 struct extent_buffer *eb)
3568 if (btrfs_header_flag(eb, BTRFS_HEADER_FLAG_RELOC) ||
3569 btrfs_header_backref_rev(eb) < BTRFS_MIXED_BACKREF_REV)
3572 ret = btrfs_lookup_extent_info(NULL, rc->extent_root->fs_info,
3573 eb->start, btrfs_header_level(eb), 1,
3577 if (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF)
3584 static int delete_block_group_cache(struct btrfs_fs_info *fs_info,
3585 struct btrfs_block_group *block_group,
3586 struct inode *inode,
3589 struct btrfs_key key;
3590 struct btrfs_root *root = fs_info->tree_root;
3591 struct btrfs_trans_handle *trans;
3598 key.type = BTRFS_INODE_ITEM_KEY;
3601 inode = btrfs_iget(fs_info->sb, &key, root);
3606 ret = btrfs_check_trunc_cache_free_space(fs_info,
3607 &fs_info->global_block_rsv);
3611 trans = btrfs_join_transaction(root);
3612 if (IS_ERR(trans)) {
3613 ret = PTR_ERR(trans);
3617 ret = btrfs_truncate_free_space_cache(trans, block_group, inode);
3619 btrfs_end_transaction(trans);
3620 btrfs_btree_balance_dirty(fs_info);
3627 * helper to add tree blocks for backref of type BTRFS_EXTENT_DATA_REF_KEY
3628 * this function scans fs tree to find blocks reference the data extent
3630 static int find_data_references(struct reloc_control *rc,
3631 struct btrfs_key *extent_key,
3632 struct extent_buffer *leaf,
3633 struct btrfs_extent_data_ref *ref,
3634 struct rb_root *blocks)
3636 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3637 struct btrfs_path *path;
3638 struct tree_block *block;
3639 struct btrfs_root *root;
3640 struct btrfs_file_extent_item *fi;
3641 struct rb_node *rb_node;
3642 struct btrfs_key key;
3653 ref_root = btrfs_extent_data_ref_root(leaf, ref);
3654 ref_objectid = btrfs_extent_data_ref_objectid(leaf, ref);
3655 ref_offset = btrfs_extent_data_ref_offset(leaf, ref);
3656 ref_count = btrfs_extent_data_ref_count(leaf, ref);
3659 * This is an extent belonging to the free space cache, lets just delete
3660 * it and redo the search.
3662 if (ref_root == BTRFS_ROOT_TREE_OBJECTID) {
3663 ret = delete_block_group_cache(fs_info, rc->block_group,
3664 NULL, ref_objectid);
3670 path = btrfs_alloc_path();
3673 path->reada = READA_FORWARD;
3675 root = read_fs_root(fs_info, ref_root);
3677 err = PTR_ERR(root);
3681 key.objectid = ref_objectid;
3682 key.type = BTRFS_EXTENT_DATA_KEY;
3683 if (ref_offset > ((u64)-1 << 32))
3686 key.offset = ref_offset;
3688 path->search_commit_root = 1;
3689 path->skip_locking = 1;
3690 ret = btrfs_search_slot(NULL, root, &key, path, 0, 0);
3696 leaf = path->nodes[0];
3697 nritems = btrfs_header_nritems(leaf);
3699 * the references in tree blocks that use full backrefs
3700 * are not counted in
3702 if (block_use_full_backref(rc, leaf))
3706 rb_node = tree_search(blocks, leaf->start);
3711 path->slots[0] = nritems;
3714 while (ref_count > 0) {
3715 while (path->slots[0] >= nritems) {
3716 ret = btrfs_next_leaf(root, path);
3721 if (WARN_ON(ret > 0))
3724 leaf = path->nodes[0];
3725 nritems = btrfs_header_nritems(leaf);
3728 if (block_use_full_backref(rc, leaf))
3732 rb_node = tree_search(blocks, leaf->start);
3737 path->slots[0] = nritems;
3741 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3742 if (WARN_ON(key.objectid != ref_objectid ||
3743 key.type != BTRFS_EXTENT_DATA_KEY))
3746 fi = btrfs_item_ptr(leaf, path->slots[0],
3747 struct btrfs_file_extent_item);
3749 if (btrfs_file_extent_type(leaf, fi) ==
3750 BTRFS_FILE_EXTENT_INLINE)
3753 if (btrfs_file_extent_disk_bytenr(leaf, fi) !=
3754 extent_key->objectid)
3757 key.offset -= btrfs_file_extent_offset(leaf, fi);
3758 if (key.offset != ref_offset)
3766 if (!tree_block_processed(leaf->start, rc)) {
3767 block = kmalloc(sizeof(*block), GFP_NOFS);
3772 block->bytenr = leaf->start;
3773 btrfs_item_key_to_cpu(leaf, &block->key, 0);
3775 block->key_ready = 1;
3776 rb_node = tree_insert(blocks, block->bytenr,
3779 backref_tree_panic(rb_node, -EEXIST,
3785 path->slots[0] = nritems;
3791 btrfs_free_path(path);
3796 * helper to find all tree blocks that reference a given data extent
3798 static noinline_for_stack
3799 int add_data_references(struct reloc_control *rc,
3800 struct btrfs_key *extent_key,
3801 struct btrfs_path *path,
3802 struct rb_root *blocks)
3804 struct btrfs_key key;
3805 struct extent_buffer *eb;
3806 struct btrfs_extent_data_ref *dref;
3807 struct btrfs_extent_inline_ref *iref;
3810 u32 blocksize = rc->extent_root->fs_info->nodesize;
3814 eb = path->nodes[0];
3815 ptr = btrfs_item_ptr_offset(eb, path->slots[0]);
3816 end = ptr + btrfs_item_size_nr(eb, path->slots[0]);
3817 ptr += sizeof(struct btrfs_extent_item);
3820 iref = (struct btrfs_extent_inline_ref *)ptr;
3821 key.type = btrfs_get_extent_inline_ref_type(eb, iref,
3822 BTRFS_REF_TYPE_DATA);
3823 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3824 key.offset = btrfs_extent_inline_ref_offset(eb, iref);
3825 ret = __add_tree_block(rc, key.offset, blocksize,
3827 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3828 dref = (struct btrfs_extent_data_ref *)(&iref->offset);
3829 ret = find_data_references(rc, extent_key,
3833 btrfs_err(rc->extent_root->fs_info,
3834 "extent %llu slot %d has an invalid inline ref type",
3835 eb->start, path->slots[0]);
3841 ptr += btrfs_extent_inline_ref_size(key.type);
3847 eb = path->nodes[0];
3848 if (path->slots[0] >= btrfs_header_nritems(eb)) {
3849 ret = btrfs_next_leaf(rc->extent_root, path);
3856 eb = path->nodes[0];
3859 btrfs_item_key_to_cpu(eb, &key, path->slots[0]);
3860 if (key.objectid != extent_key->objectid)
3863 if (key.type == BTRFS_SHARED_DATA_REF_KEY) {
3864 ret = __add_tree_block(rc, key.offset, blocksize,
3866 } else if (key.type == BTRFS_EXTENT_DATA_REF_KEY) {
3867 dref = btrfs_item_ptr(eb, path->slots[0],
3868 struct btrfs_extent_data_ref);
3869 ret = find_data_references(rc, extent_key,
3871 } else if (unlikely(key.type == BTRFS_EXTENT_REF_V0_KEY)) {
3872 btrfs_print_v0_err(eb->fs_info);
3873 btrfs_handle_fs_error(eb->fs_info, -EINVAL, NULL);
3885 btrfs_release_path(path);
3887 free_block_list(blocks);
3892 * helper to find next unprocessed extent
3894 static noinline_for_stack
3895 int find_next_extent(struct reloc_control *rc, struct btrfs_path *path,
3896 struct btrfs_key *extent_key)
3898 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3899 struct btrfs_key key;
3900 struct extent_buffer *leaf;
3901 u64 start, end, last;
3904 last = rc->block_group->start + rc->block_group->length;
3907 if (rc->search_start >= last) {
3912 key.objectid = rc->search_start;
3913 key.type = BTRFS_EXTENT_ITEM_KEY;
3916 path->search_commit_root = 1;
3917 path->skip_locking = 1;
3918 ret = btrfs_search_slot(NULL, rc->extent_root, &key, path,
3923 leaf = path->nodes[0];
3924 if (path->slots[0] >= btrfs_header_nritems(leaf)) {
3925 ret = btrfs_next_leaf(rc->extent_root, path);
3928 leaf = path->nodes[0];
3931 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
3932 if (key.objectid >= last) {
3937 if (key.type != BTRFS_EXTENT_ITEM_KEY &&
3938 key.type != BTRFS_METADATA_ITEM_KEY) {
3943 if (key.type == BTRFS_EXTENT_ITEM_KEY &&
3944 key.objectid + key.offset <= rc->search_start) {
3949 if (key.type == BTRFS_METADATA_ITEM_KEY &&
3950 key.objectid + fs_info->nodesize <=
3956 ret = find_first_extent_bit(&rc->processed_blocks,
3957 key.objectid, &start, &end,
3958 EXTENT_DIRTY, NULL);
3960 if (ret == 0 && start <= key.objectid) {
3961 btrfs_release_path(path);
3962 rc->search_start = end + 1;
3964 if (key.type == BTRFS_EXTENT_ITEM_KEY)
3965 rc->search_start = key.objectid + key.offset;
3967 rc->search_start = key.objectid +
3969 memcpy(extent_key, &key, sizeof(key));
3973 btrfs_release_path(path);
3977 static void set_reloc_control(struct reloc_control *rc)
3979 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3981 mutex_lock(&fs_info->reloc_mutex);
3982 fs_info->reloc_ctl = rc;
3983 mutex_unlock(&fs_info->reloc_mutex);
3986 static void unset_reloc_control(struct reloc_control *rc)
3988 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
3990 mutex_lock(&fs_info->reloc_mutex);
3991 fs_info->reloc_ctl = NULL;
3992 mutex_unlock(&fs_info->reloc_mutex);
3995 static int check_extent_flags(u64 flags)
3997 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
3998 (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
4000 if (!(flags & BTRFS_EXTENT_FLAG_DATA) &&
4001 !(flags & BTRFS_EXTENT_FLAG_TREE_BLOCK))
4003 if ((flags & BTRFS_EXTENT_FLAG_DATA) &&
4004 (flags & BTRFS_BLOCK_FLAG_FULL_BACKREF))
4009 static noinline_for_stack
4010 int prepare_to_relocate(struct reloc_control *rc)
4012 struct btrfs_trans_handle *trans;
4015 rc->block_rsv = btrfs_alloc_block_rsv(rc->extent_root->fs_info,
4016 BTRFS_BLOCK_RSV_TEMP);
4020 memset(&rc->cluster, 0, sizeof(rc->cluster));
4021 rc->search_start = rc->block_group->start;
4022 rc->extents_found = 0;
4023 rc->nodes_relocated = 0;
4024 rc->merging_rsv_size = 0;
4025 rc->reserved_bytes = 0;
4026 rc->block_rsv->size = rc->extent_root->fs_info->nodesize *
4027 RELOCATION_RESERVED_NODES;
4028 ret = btrfs_block_rsv_refill(rc->extent_root,
4029 rc->block_rsv, rc->block_rsv->size,
4030 BTRFS_RESERVE_FLUSH_ALL);
4034 rc->create_reloc_tree = 1;
4035 set_reloc_control(rc);
4037 trans = btrfs_join_transaction(rc->extent_root);
4038 if (IS_ERR(trans)) {
4039 unset_reloc_control(rc);
4041 * extent tree is not a ref_cow tree and has no reloc_root to
4042 * cleanup. And callers are responsible to free the above
4045 return PTR_ERR(trans);
4047 btrfs_commit_transaction(trans);
4051 static noinline_for_stack int relocate_block_group(struct reloc_control *rc)
4053 struct btrfs_fs_info *fs_info = rc->extent_root->fs_info;
4054 struct rb_root blocks = RB_ROOT;
4055 struct btrfs_key key;
4056 struct btrfs_trans_handle *trans = NULL;
4057 struct btrfs_path *path;
4058 struct btrfs_extent_item *ei;
4065 path = btrfs_alloc_path();
4068 path->reada = READA_FORWARD;
4070 ret = prepare_to_relocate(rc);
4077 rc->reserved_bytes = 0;
4078 ret = btrfs_block_rsv_refill(rc->extent_root,
4079 rc->block_rsv, rc->block_rsv->size,
4080 BTRFS_RESERVE_FLUSH_ALL);
4086 trans = btrfs_start_transaction(rc->extent_root, 0);
4087 if (IS_ERR(trans)) {
4088 err = PTR_ERR(trans);
4093 if (update_backref_cache(trans, &rc->backref_cache)) {
4094 btrfs_end_transaction(trans);
4099 ret = find_next_extent(rc, path, &key);
4105 rc->extents_found++;
4107 ei = btrfs_item_ptr(path->nodes[0], path->slots[0],
4108 struct btrfs_extent_item);
4109 item_size = btrfs_item_size_nr(path->nodes[0], path->slots[0]);
4110 if (item_size >= sizeof(*ei)) {
4111 flags = btrfs_extent_flags(path->nodes[0], ei);
4112 ret = check_extent_flags(flags);
4114 } else if (unlikely(item_size == sizeof(struct btrfs_extent_item_v0))) {
4116 btrfs_print_v0_err(trans->fs_info);
4117 btrfs_abort_transaction(trans, err);
4123 if (flags & BTRFS_EXTENT_FLAG_TREE_BLOCK) {
4124 ret = add_tree_block(rc, &key, path, &blocks);
4125 } else if (rc->stage == UPDATE_DATA_PTRS &&
4126 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4127 ret = add_data_references(rc, &key, path, &blocks);
4129 btrfs_release_path(path);
4137 if (!RB_EMPTY_ROOT(&blocks)) {
4138 ret = relocate_tree_blocks(trans, rc, &blocks);
4141 * if we fail to relocate tree blocks, force to update
4142 * backref cache when committing transaction.
4144 rc->backref_cache.last_trans = trans->transid - 1;
4146 if (ret != -EAGAIN) {
4150 rc->extents_found--;
4151 rc->search_start = key.objectid;
4155 btrfs_end_transaction_throttle(trans);
4156 btrfs_btree_balance_dirty(fs_info);
4159 if (rc->stage == MOVE_DATA_EXTENTS &&
4160 (flags & BTRFS_EXTENT_FLAG_DATA)) {
4161 rc->found_file_extent = 1;
4162 ret = relocate_data_extent(rc->data_inode,
4163 &key, &rc->cluster);
4170 if (trans && progress && err == -ENOSPC) {
4171 ret = btrfs_force_chunk_alloc(trans, rc->block_group->flags);
4179 btrfs_release_path(path);
4180 clear_extent_bits(&rc->processed_blocks, 0, (u64)-1, EXTENT_DIRTY);
4183 btrfs_end_transaction_throttle(trans);
4184 btrfs_btree_balance_dirty(fs_info);
4188 ret = relocate_file_extent_cluster(rc->data_inode,
4194 rc->create_reloc_tree = 0;
4195 set_reloc_control(rc);
4197 backref_cache_cleanup(&rc->backref_cache);
4198 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4200 err = prepare_to_merge(rc, err);
4202 merge_reloc_roots(rc);
4204 rc->merge_reloc_tree = 0;
4205 unset_reloc_control(rc);
4206 btrfs_block_rsv_release(fs_info, rc->block_rsv, (u64)-1);
4208 /* get rid of pinned extents */
4209 trans = btrfs_join_transaction(rc->extent_root);
4210 if (IS_ERR(trans)) {
4211 err = PTR_ERR(trans);
4214 btrfs_commit_transaction(trans);
4215 ret = clean_dirty_subvols(rc);
4216 if (ret < 0 && !err)
4219 btrfs_free_block_rsv(fs_info, rc->block_rsv);
4220 btrfs_free_path(path);
4224 static int __insert_orphan_inode(struct btrfs_trans_handle *trans,
4225 struct btrfs_root *root, u64 objectid)
4227 struct btrfs_path *path;
4228 struct btrfs_inode_item *item;
4229 struct extent_buffer *leaf;
4232 path = btrfs_alloc_path();
4236 ret = btrfs_insert_empty_inode(trans, root, path, objectid);
4240 leaf = path->nodes[0];
4241 item = btrfs_item_ptr(leaf, path->slots[0], struct btrfs_inode_item);
4242 memzero_extent_buffer(leaf, (unsigned long)item, sizeof(*item));
4243 btrfs_set_inode_generation(leaf, item, 1);
4244 btrfs_set_inode_size(leaf, item, 0);
4245 btrfs_set_inode_mode(leaf, item, S_IFREG | 0600);
4246 btrfs_set_inode_flags(leaf, item, BTRFS_INODE_NOCOMPRESS |
4247 BTRFS_INODE_PREALLOC);
4248 btrfs_mark_buffer_dirty(leaf);
4250 btrfs_free_path(path);
4255 * helper to create inode for data relocation.
4256 * the inode is in data relocation tree and its link count is 0
4258 static noinline_for_stack
4259 struct inode *create_reloc_inode(struct btrfs_fs_info *fs_info,
4260 struct btrfs_block_group *group)
4262 struct inode *inode = NULL;
4263 struct btrfs_trans_handle *trans;
4264 struct btrfs_root *root;
4265 struct btrfs_key key;
4269 root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4271 return ERR_CAST(root);
4273 trans = btrfs_start_transaction(root, 6);
4275 return ERR_CAST(trans);
4277 err = btrfs_find_free_objectid(root, &objectid);
4281 err = __insert_orphan_inode(trans, root, objectid);
4284 key.objectid = objectid;
4285 key.type = BTRFS_INODE_ITEM_KEY;
4287 inode = btrfs_iget(fs_info->sb, &key, root);
4288 BUG_ON(IS_ERR(inode));
4289 BTRFS_I(inode)->index_cnt = group->start;
4291 err = btrfs_orphan_add(trans, BTRFS_I(inode));
4293 btrfs_end_transaction(trans);
4294 btrfs_btree_balance_dirty(fs_info);
4298 inode = ERR_PTR(err);
4303 static struct reloc_control *alloc_reloc_control(struct btrfs_fs_info *fs_info)
4305 struct reloc_control *rc;
4307 rc = kzalloc(sizeof(*rc), GFP_NOFS);
4311 INIT_LIST_HEAD(&rc->reloc_roots);
4312 INIT_LIST_HEAD(&rc->dirty_subvol_roots);
4313 backref_cache_init(&rc->backref_cache);
4314 mapping_tree_init(&rc->reloc_root_tree);
4315 extent_io_tree_init(fs_info, &rc->processed_blocks,
4316 IO_TREE_RELOC_BLOCKS, NULL);
4321 * Print the block group being relocated
4323 static void describe_relocation(struct btrfs_fs_info *fs_info,
4324 struct btrfs_block_group *block_group)
4326 char buf[128] = {'\0'};
4328 btrfs_describe_block_groups(block_group->flags, buf, sizeof(buf));
4331 "relocating block group %llu flags %s",
4332 block_group->start, buf);
4336 * function to relocate all extents in a block group.
4338 int btrfs_relocate_block_group(struct btrfs_fs_info *fs_info, u64 group_start)
4340 struct btrfs_block_group *bg;
4341 struct btrfs_root *extent_root = fs_info->extent_root;
4342 struct reloc_control *rc;
4343 struct inode *inode;
4344 struct btrfs_path *path;
4349 bg = btrfs_lookup_block_group(fs_info, group_start);
4353 if (btrfs_pinned_by_swapfile(fs_info, bg)) {
4354 btrfs_put_block_group(bg);
4358 rc = alloc_reloc_control(fs_info);
4360 btrfs_put_block_group(bg);
4364 rc->extent_root = extent_root;
4365 rc->block_group = bg;
4367 ret = btrfs_inc_block_group_ro(rc->block_group, true);
4374 path = btrfs_alloc_path();
4380 inode = lookup_free_space_inode(rc->block_group, path);
4381 btrfs_free_path(path);
4384 ret = delete_block_group_cache(fs_info, rc->block_group, inode, 0);
4386 ret = PTR_ERR(inode);
4388 if (ret && ret != -ENOENT) {
4393 rc->data_inode = create_reloc_inode(fs_info, rc->block_group);
4394 if (IS_ERR(rc->data_inode)) {
4395 err = PTR_ERR(rc->data_inode);
4396 rc->data_inode = NULL;
4400 describe_relocation(fs_info, rc->block_group);
4402 btrfs_wait_block_group_reservations(rc->block_group);
4403 btrfs_wait_nocow_writers(rc->block_group);
4404 btrfs_wait_ordered_roots(fs_info, U64_MAX,
4405 rc->block_group->start,
4406 rc->block_group->length);
4409 mutex_lock(&fs_info->cleaner_mutex);
4410 ret = relocate_block_group(rc);
4411 mutex_unlock(&fs_info->cleaner_mutex);
4416 * We may have gotten ENOSPC after we already dirtied some
4417 * extents. If writeout happens while we're relocating a
4418 * different block group we could end up hitting the
4419 * BUG_ON(rc->stage == UPDATE_DATA_PTRS) in
4420 * btrfs_reloc_cow_block. Make sure we write everything out
4421 * properly so we don't trip over this problem, and then break
4422 * out of the loop if we hit an error.
4424 if (rc->stage == MOVE_DATA_EXTENTS && rc->found_file_extent) {
4425 ret = btrfs_wait_ordered_range(rc->data_inode, 0,
4429 invalidate_mapping_pages(rc->data_inode->i_mapping,
4431 rc->stage = UPDATE_DATA_PTRS;
4437 if (rc->extents_found == 0)
4440 btrfs_info(fs_info, "found %llu extents", rc->extents_found);
4444 WARN_ON(rc->block_group->pinned > 0);
4445 WARN_ON(rc->block_group->reserved > 0);
4446 WARN_ON(rc->block_group->used > 0);
4449 btrfs_dec_block_group_ro(rc->block_group);
4450 iput(rc->data_inode);
4451 btrfs_put_block_group(rc->block_group);
4456 static noinline_for_stack int mark_garbage_root(struct btrfs_root *root)
4458 struct btrfs_fs_info *fs_info = root->fs_info;
4459 struct btrfs_trans_handle *trans;
4462 trans = btrfs_start_transaction(fs_info->tree_root, 0);
4464 return PTR_ERR(trans);
4466 memset(&root->root_item.drop_progress, 0,
4467 sizeof(root->root_item.drop_progress));
4468 root->root_item.drop_level = 0;
4469 btrfs_set_root_refs(&root->root_item, 0);
4470 ret = btrfs_update_root(trans, fs_info->tree_root,
4471 &root->root_key, &root->root_item);
4473 err = btrfs_end_transaction(trans);
4480 * recover relocation interrupted by system crash.
4482 * this function resumes merging reloc trees with corresponding fs trees.
4483 * this is important for keeping the sharing of tree blocks
4485 int btrfs_recover_relocation(struct btrfs_root *root)
4487 struct btrfs_fs_info *fs_info = root->fs_info;
4488 LIST_HEAD(reloc_roots);
4489 struct btrfs_key key;
4490 struct btrfs_root *fs_root;
4491 struct btrfs_root *reloc_root;
4492 struct btrfs_path *path;
4493 struct extent_buffer *leaf;
4494 struct reloc_control *rc = NULL;
4495 struct btrfs_trans_handle *trans;
4499 path = btrfs_alloc_path();
4502 path->reada = READA_BACK;
4504 key.objectid = BTRFS_TREE_RELOC_OBJECTID;
4505 key.type = BTRFS_ROOT_ITEM_KEY;
4506 key.offset = (u64)-1;
4509 ret = btrfs_search_slot(NULL, fs_info->tree_root, &key,
4516 if (path->slots[0] == 0)
4520 leaf = path->nodes[0];
4521 btrfs_item_key_to_cpu(leaf, &key, path->slots[0]);
4522 btrfs_release_path(path);
4524 if (key.objectid != BTRFS_TREE_RELOC_OBJECTID ||
4525 key.type != BTRFS_ROOT_ITEM_KEY)
4528 reloc_root = btrfs_read_fs_root(root, &key);
4529 if (IS_ERR(reloc_root)) {
4530 err = PTR_ERR(reloc_root);
4534 list_add(&reloc_root->root_list, &reloc_roots);
4536 if (btrfs_root_refs(&reloc_root->root_item) > 0) {
4537 fs_root = read_fs_root(fs_info,
4538 reloc_root->root_key.offset);
4539 if (IS_ERR(fs_root)) {
4540 ret = PTR_ERR(fs_root);
4541 if (ret != -ENOENT) {
4545 ret = mark_garbage_root(reloc_root);
4553 if (key.offset == 0)
4558 btrfs_release_path(path);
4560 if (list_empty(&reloc_roots))
4563 rc = alloc_reloc_control(fs_info);
4569 rc->extent_root = fs_info->extent_root;
4571 set_reloc_control(rc);
4573 trans = btrfs_join_transaction(rc->extent_root);
4574 if (IS_ERR(trans)) {
4575 unset_reloc_control(rc);
4576 err = PTR_ERR(trans);
4580 rc->merge_reloc_tree = 1;
4582 while (!list_empty(&reloc_roots)) {
4583 reloc_root = list_entry(reloc_roots.next,
4584 struct btrfs_root, root_list);
4585 list_del(&reloc_root->root_list);
4587 if (btrfs_root_refs(&reloc_root->root_item) == 0) {
4588 list_add_tail(&reloc_root->root_list,
4593 fs_root = read_fs_root(fs_info, reloc_root->root_key.offset);
4594 if (IS_ERR(fs_root)) {
4595 err = PTR_ERR(fs_root);
4596 list_add_tail(&reloc_root->root_list, &reloc_roots);
4600 err = __add_reloc_root(reloc_root);
4601 BUG_ON(err < 0); /* -ENOMEM or logic error */
4602 fs_root->reloc_root = reloc_root;
4605 err = btrfs_commit_transaction(trans);
4609 merge_reloc_roots(rc);
4611 unset_reloc_control(rc);
4613 trans = btrfs_join_transaction(rc->extent_root);
4614 if (IS_ERR(trans)) {
4615 err = PTR_ERR(trans);
4618 err = btrfs_commit_transaction(trans);
4620 ret = clean_dirty_subvols(rc);
4621 if (ret < 0 && !err)
4626 if (!list_empty(&reloc_roots))
4627 free_reloc_roots(&reloc_roots);
4629 btrfs_free_path(path);
4632 /* cleanup orphan inode in data relocation tree */
4633 fs_root = read_fs_root(fs_info, BTRFS_DATA_RELOC_TREE_OBJECTID);
4634 if (IS_ERR(fs_root))
4635 err = PTR_ERR(fs_root);
4637 err = btrfs_orphan_cleanup(fs_root);
4643 * helper to add ordered checksum for data relocation.
4645 * cloning checksum properly handles the nodatasum extents.
4646 * it also saves CPU time to re-calculate the checksum.
4648 int btrfs_reloc_clone_csums(struct inode *inode, u64 file_pos, u64 len)
4650 struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
4651 struct btrfs_ordered_sum *sums;
4652 struct btrfs_ordered_extent *ordered;
4658 ordered = btrfs_lookup_ordered_extent(inode, file_pos);
4659 BUG_ON(ordered->file_offset != file_pos || ordered->len != len);
4661 disk_bytenr = file_pos + BTRFS_I(inode)->index_cnt;
4662 ret = btrfs_lookup_csums_range(fs_info->csum_root, disk_bytenr,
4663 disk_bytenr + len - 1, &list, 0);
4667 while (!list_empty(&list)) {
4668 sums = list_entry(list.next, struct btrfs_ordered_sum, list);
4669 list_del_init(&sums->list);
4672 * We need to offset the new_bytenr based on where the csum is.
4673 * We need to do this because we will read in entire prealloc
4674 * extents but we may have written to say the middle of the
4675 * prealloc extent, so we need to make sure the csum goes with
4676 * the right disk offset.
4678 * We can do this because the data reloc inode refers strictly
4679 * to the on disk bytes, so we don't have to worry about
4680 * disk_len vs real len like with real inodes since it's all
4683 new_bytenr = ordered->start + (sums->bytenr - disk_bytenr);
4684 sums->bytenr = new_bytenr;
4686 btrfs_add_ordered_sum(ordered, sums);
4689 btrfs_put_ordered_extent(ordered);
4693 int btrfs_reloc_cow_block(struct btrfs_trans_handle *trans,
4694 struct btrfs_root *root, struct extent_buffer *buf,
4695 struct extent_buffer *cow)
4697 struct btrfs_fs_info *fs_info = root->fs_info;
4698 struct reloc_control *rc;
4699 struct backref_node *node;
4704 rc = fs_info->reloc_ctl;
4708 BUG_ON(rc->stage == UPDATE_DATA_PTRS &&
4709 root->root_key.objectid == BTRFS_DATA_RELOC_TREE_OBJECTID);
4711 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID) {
4712 if (buf == root->node)
4713 __update_reloc_root(root, cow->start);
4716 level = btrfs_header_level(buf);
4717 if (btrfs_header_generation(buf) <=
4718 btrfs_root_last_snapshot(&root->root_item))
4721 if (root->root_key.objectid == BTRFS_TREE_RELOC_OBJECTID &&
4722 rc->create_reloc_tree) {
4723 WARN_ON(!first_cow && level == 0);
4725 node = rc->backref_cache.path[level];
4726 BUG_ON(node->bytenr != buf->start &&
4727 node->new_bytenr != buf->start);
4729 drop_node_buffer(node);
4730 atomic_inc(&cow->refs);
4732 node->new_bytenr = cow->start;
4734 if (!node->pending) {
4735 list_move_tail(&node->list,
4736 &rc->backref_cache.pending[level]);
4741 __mark_block_processed(rc, node);
4743 if (first_cow && level > 0)
4744 rc->nodes_relocated += buf->len;
4747 if (level == 0 && first_cow && rc->stage == UPDATE_DATA_PTRS)
4748 ret = replace_file_extents(trans, rc, root, cow);
4753 * called before creating snapshot. it calculates metadata reservation
4754 * required for relocating tree blocks in the snapshot
4756 void btrfs_reloc_pre_snapshot(struct btrfs_pending_snapshot *pending,
4757 u64 *bytes_to_reserve)
4759 struct btrfs_root *root = pending->root;
4760 struct reloc_control *rc = root->fs_info->reloc_ctl;
4762 if (!rc || !have_reloc_root(root))
4765 if (!rc->merge_reloc_tree)
4768 root = root->reloc_root;
4769 BUG_ON(btrfs_root_refs(&root->root_item) == 0);
4771 * relocation is in the stage of merging trees. the space
4772 * used by merging a reloc tree is twice the size of
4773 * relocated tree nodes in the worst case. half for cowing
4774 * the reloc tree, half for cowing the fs tree. the space
4775 * used by cowing the reloc tree will be freed after the
4776 * tree is dropped. if we create snapshot, cowing the fs
4777 * tree may use more space than it frees. so we need
4778 * reserve extra space.
4780 *bytes_to_reserve += rc->nodes_relocated;
4784 * called after snapshot is created. migrate block reservation
4785 * and create reloc root for the newly created snapshot
4787 int btrfs_reloc_post_snapshot(struct btrfs_trans_handle *trans,
4788 struct btrfs_pending_snapshot *pending)
4790 struct btrfs_root *root = pending->root;
4791 struct btrfs_root *reloc_root;
4792 struct btrfs_root *new_root;
4793 struct reloc_control *rc = root->fs_info->reloc_ctl;
4796 if (!rc || !have_reloc_root(root))
4799 rc = root->fs_info->reloc_ctl;
4800 rc->merging_rsv_size += rc->nodes_relocated;
4802 if (rc->merge_reloc_tree) {
4803 ret = btrfs_block_rsv_migrate(&pending->block_rsv,
4805 rc->nodes_relocated, true);
4810 new_root = pending->snap;
4811 reloc_root = create_reloc_root(trans, root->reloc_root,
4812 new_root->root_key.objectid);
4813 if (IS_ERR(reloc_root))
4814 return PTR_ERR(reloc_root);
4816 ret = __add_reloc_root(reloc_root);
4818 new_root->reloc_root = reloc_root;
4820 if (rc->create_reloc_tree)
4821 ret = clone_backref_node(trans, rc, root, reloc_root);