btrfs_get_new_fs_root
struct btrfs_root *btrfs_get_new_fs_root(struct btrfs_fs_info *fs_info,
new_root = btrfs_get_new_fs_root(fs_info, objectid, &anon_dev);
pending->snap = btrfs_get_new_fs_root(fs_info, objectid, &pending->anon_dev);