{
    # parse fstab to know what fstype is root partition
    my $fstype = "ext4";
    my @patterns =  (  qr/\s\/\s+xfs\s+/, qr/^\/dev\/main\/.*\s+xfs\s+/ );
    open (RD, "</etc/fstab")
    || warn "Cannot open input file /etc/fstab: $!\n";
    while (<RD>)
    {
        chop;
        $fstype="xfs" if ( $_ ~~ @patterns );
    }
    close(RD);

    if ( $fstype eq "xfs" ) {
        # GRUB_CMDLINE_LINUX="rd.lvm.lv=main/root rd.lvm.lv=main/swap rhgb quiet"
        # to GRUB_CMDLINE_LINUX="rd.lvm.lv=main/root rd.lvm.lv=main/swap rhgb quiet rootflags=uquota,pquota"
        # also remove noquota
        @lines = map {
                /^GRUB_CMDLINE_LINUX/ && s/noquota//;
                /^GRUB_CMDLINE_LINUX/ && ! /rootflags=uquota,pquota/ && s/"$/ rootflags=uquota,pquota"/;
                $_
                } @lines;
    } else {
        # if we are using ext[234] or any other fs type let's default to ...
        @lines = map {
                /^GRUB_CMDLINE_LINUX/ && s/noquota//;
                /^GRUB_CMDLINE_LINUX/ && /rootflags=uquota,pquota/ && s/rootflags=uquota,pquota//;
                $_
                } @lines;


    }
    "";
}

