anchor.diff:  
   ###### implementation
   
  -  inherit (pkgs) e2fsprogs;
     fileSystems = config.fileSystems;
     mountPoints = map (fs: fs.mountPoint) fileSystems;
  -  devices = map (fs: if fs.device != null then fs.device else "LABEL=" + fs.label) fileSystems;
  +  devices = map (fs: if fs.device != null then fs.device else "/dev/disk/by-label/${fs.label}") fileSystems;
     fsTypes = map (fs: fs.fsType) fileSystems;
     optionss = map (fs: fs.options) fileSystems;
     autocreates = map (fs: fs.autocreate) fileSystems;
  
positive.code:           options=''${optionss[$n]}
            autocreate=''${autocreates[$n]}
  
            isLabel=
            if echo "$device" | grep -q '^LABEL='; then isLabel=1; fi
  
            isPseudo=
            if test "$fsType" = "nfs" || test "$fsType" = "tmpfs" ||
              test "$fsType" = "ext3cow"; then isPseudo=1; fi
  
            if ! test -n "$isLabel" -o -n "$isPseudo" -o -e "$device"; then
                echo "skipping $device, doesn't exist (yet)"
                continue
            fi
  
            # !!! quick hack: if mount point already exists, try a
            # remount to change the options but nothing else.
            if cat /proc/mounts | grep -F -q " $mountPoint "; then
                echo "remounting $device on $mountPoint"
                ${mount}/bin/mount -t "$fsType" \
                    -o remount,"$options" \
                    "$device" "$mountPoint" || true
                continue
            fi
  
  
negative.code:     start on ip-up
  
      script
        PATH=${pkgs.e2fsprogs}/sbin:${pkgs.utillinuxng}/sbin:$PATH
  
        mountPoints=(${toString mountPoints})  
        devices=(${toString devices})
  