btrfs_read_tree_root
root = btrfs_read_tree_root(fs_info->tree_root, &key);
root = btrfs_read_tree_root(tree_root, &location);
root = btrfs_read_tree_root(tree_root, &location);
root = btrfs_read_tree_root(fs_info->tree_root, &location);
root = btrfs_read_tree_root(tree_root, &location);
root = btrfs_read_tree_root(tree_root, &location);
root = btrfs_read_tree_root(tree_root, &location);
struct btrfs_root *btrfs_read_tree_root(struct btrfs_root *tree_root,
reloc_root = btrfs_read_tree_root(fs_info->tree_root, &key);
reloc_root = btrfs_read_tree_root(fs_info->tree_root, &root_key);
wc.log = btrfs_read_tree_root(log_root_tree, &found_key);