xfs_rtcheck_range
error = xfs_rtcheck_range(args, start, len, 0, &new, &stat);
error = xfs_rtcheck_range(&args, start, 1, 1, &rtend,
error = xfs_rtcheck_range(&args, start, len, 1, &end, &matches);
int xfs_rtcheck_range(struct xfs_rtalloc_args *args, xfs_rtxnum_t start,
error = xfs_rtcheck_range(args, i, scanlen, 1, &next, &stat);
error = xfs_rtcheck_range(args, start, scanlen, 1, &next, &isfree);