diff options
| -rw-r--r-- | fs/btrfs/relocation.c | 28 |
1 files changed, 18 insertions, 10 deletions
diff --git a/fs/btrfs/relocation.c b/fs/btrfs/relocation.c index 87afd3c395bb..a5c5e9b3aceb 100644 --- a/fs/btrfs/relocation.c +++ b/fs/btrfs/relocation.c @@ -648,8 +648,8 @@ struct backref_node *build_backref_tree(struct reloc_control *rc, int level, u64 bytenr) { struct backref_cache *cache = &rc->backref_cache; - struct btrfs_path *path1; - struct btrfs_path *path2; + struct btrfs_path *path1; /* For searching extent root */ + struct btrfs_path *path2; /* For searching parent of TREE_BLOCK_REF */ struct extent_buffer *eb; struct btrfs_root *root; struct backref_node *cur; @@ -662,7 +662,7 @@ struct backref_node *build_backref_tree(struct reloc_control *rc, struct btrfs_key key; unsigned long end; unsigned long ptr; - LIST_HEAD(list); + LIST_HEAD(list); /* Pending edge list, upper node needs to be checked */ LIST_HEAD(useless); int cowonly; int ret; @@ -778,6 +778,10 @@ again: key.type != BTRFS_SHARED_BLOCK_REF_KEY); } + /* + * Parent node found and matches current inline ref, no need to + * rebuild this node for this inline ref. + */ if (exist && ((key.type == BTRFS_TREE_BLOCK_REF_KEY && exist->owner == key.offset) || @@ -787,11 +791,12 @@ again: goto next; } + /* SHARED_BLOCK_REF means key.offset is the parent bytenr */ if (key.type == BTRFS_SHARED_BLOCK_REF_KEY) { if (key.objectid == key.offset) { /* - * only root blocks of reloc trees use - * backref of this type. + * Only root blocks of reloc trees use backref + * pointing to itself. */ root = find_reloc_root(rc, cur->bytenr); ASSERT(root); @@ -840,7 +845,11 @@ again: goto next; } - /* key.type == BTRFS_TREE_BLOCK_REF_KEY */ + /* + * key.type == BTRFS_TREE_BLOCK_REF_KEY, inline ref offset + * means the root objectid. We need to search the tree to get + * its parent bytenr. + */ root = read_fs_root(rc->extent_root->fs_info, key.offset); if (IS_ERR(root)) { err = PTR_ERR(root); @@ -863,10 +872,7 @@ again: level = cur->level + 1; - /* - * searching the tree to find upper level blocks - * reference the block. - */ + /* Search the tree to find parent blocks referring the block. */ path2->search_commit_root = 1; path2->skip_locking = 1; path2->lowest_level = level; @@ -893,6 +899,8 @@ again: } lower = cur; need_check = true; + + /* Add all nodes and edges in the path */ for (; level < BTRFS_MAX_LEVEL; level++) { if (!path2->nodes[level]) { ASSERT(btrfs_root_bytenr(&root->root_item) == |