Merge remote-tracking branch 'grml'

diff --combined components/9990-misc-helpers.sh
index 83eca32,a97615b..39e609d
--- 1/components/9990-misc-helpers.sh
--- 2/components/9990-misc-helpers.sh
+++ b/components/9990-misc-helpers.sh
@@@ -114,7 -114,7 +114,7 @@@ check_dev (
                                ISO_DEVICE=$(dirname ${ISO_DEVICE})
                                [ -b "$ISO_DEVICE" ] && break
                                i=$(($i -1))
 -                      done
 +                      done
                fi
  
                if [ "$ISO_DEVICE" = "/" ]
@@@ -420,6 -420,12 +420,12 @@@ is_supported_fs (
                return 1
        fi
  
+       # get_fstype might report "unknown" or "swap", ignore it as no such kernel module exists
+       if [ "${fstype}" = "unknown" ] || [ "${fstype}" = "swap" ]
+       then
+               return 1
+       fi
+ 
        # Try to look if it is already supported by the kernel
        if grep -q ${fstype} /proc/filesystems
        then
@@@ -1074,18 -1080,18 +1080,18 @@@ find_persistence_media (
                        result=$(probe_for_file_name "${overlays}" ${dev})
                        if [ -n "${result}" ]
                        then
 -                              local loopdevice
 +                              local loopdevice
                                loopdevice=${result##*=}
 -                              if is_in_comma_sep_list luks ${PERSISTENCE_ENCRYPTION} && is_luks_partition ${loopdevice}
 +                              if is_in_comma_sep_list luks ${PERSISTENCE_ENCRYPTION} && is_luks_partition ${loopdevice}
                                then
 -                                      local luksfile
 +                                      local luksfile
                                        luksfile=""
                                        if luksfile=$(open_luks_device "${loopdevice}")
                                        then
 -                                              result=${result%%=*}
 +                                              result=${result%%=*}
                                                result="${result}=${luksfile}"
                                        else
 -                                              losetup -d $loopdevice
 +                                              losetup -d $loopdevice
                                                result=""
                                        fi
                                fi
@@@ -1304,14 -1310,15 +1310,14 @@@ do_union (
                        ;;
  
                overlay)
 -                      # XXX: can multiple unionro be used? (overlay only handles two dirs, but perhaps they can be chained?)
 -                      # XXX: and can unionro be optional? i.e. can overlay skip lowerdir?
 -                      if echo ${unionro} | grep -q " "
 -                      then
 -                              panic "Multiple lower filesystems are currently not supported with overlay (unionro = ${unionro})."
 -                      elif [ -z "${unionro}"  ]
 +                      # XXX: can unionro be optional? i.e. can overlay skip lowerdir?
 +                      if [ -z "${unionro}" ]
                        then
                                panic "overlay needs at least one lower filesystem (read-only branch)."
                        fi
 +                      # Multiple lower layers can now be given using the the colon (":") as a
 +                      # separator character between the directory names.
 +                      unionro="$(echo ${unionro} | sed -e 's| |:|g')"
                        # overlayfs requires:
                        # + a workdir to become mounted
                        # + workdir and upperdir to reside under the same mount