sub create_sparse {
    my ($file, $size) = @_;
    return if -e $file && ! -f _;
    return -2 if -e _ && -s _ >= $size;

    open my $fh, '+>', $file or return;
    eval {
        seek $fh, $size, 0 or die;
        truncate $fh, $size or die;
    } or do {
        close $fh;
        return;
    };
    close $fh or return;
    return -1;
}