resize logical volumes in volume groups on multipath devices only works with one logical volume per volume group

gistfile1.txt

#!/bin/bash -ue

function list_paths() {
  multipath -ll -v 1
}

function print_usage() {
  cat <<EOF
Multipath device resizer
Resize multipath device if one LV in one VG on a multipath device PV
with FS supported by resize2fs.

Usage: ${0} [-h|-l] <multipath device>
  -h  Halp
  -l  List available multipath devices

EOF
}

while getopts hl o
do
  case $o in
    h)
      print_usage ; exit ;;
    l)
      list_paths ; exit ;;
  esac
done
shift $(($OPTIND-1))

[ $# -eq 0 ] && { echo 'error: you must provide at least one multipath device to resize'; exit 1; }
mdevices="${@}"

available_mdevices=($(list_paths))

for mdevice in ${mdevices}; do
  # check if mdevice exists in list of valid mdevices using substring removel
  [[ "${available_mdevices[@]}" == "${available_mdevices[@]#${mdevice}}" ]] && { echo "error: mdevice ${mdevice} does not seem to be a valid one"; continue; }
  # find devices
  # XXX: is there a better way to list devices?
  echo "resizing multipath device ${mdevice}"
  devices=$( multipath -ll "${mdevice}" | grep 'active\]\[ready' | awk '{ print $3 }' )
  [ "${devices}" == "" ] && { echo "error: no devices found for ${mdevice}"; continue; }

  # rescan devices
  for a in ${devices}; do echo 1 >/sys/block/$a/device/rescan; done

  multipathd -k"resize map ${mdevice}"
  #pvresize /dev/mpath/${mdevice}
  # XXX: this is not so pretty
  p=$( echo $mdevice | sed -e 's/3[Pp]ar[12]_//' -e "s/$(hostname -s)_//" -e 's/_1$//' ) || true
  #pvinfo=($( pvs --noheadings -o pv_name,vg_name | grep $mdevice ))
  # ughh, a lot of special cases in naming. ugggly trix for catching more cases follows..
  pvinfo=($( pvs --noheadings -o pv_name,vg_name | grep $p )) || true
  [ "${pvinfo:-}" == "" ] && p=$( echo $mdevice | sed -e 's/3[Pp]ar[12]_//' -e "s/$(hostname -s)_//" -e 's/_1$//' -e 's/_data//')
  # intentional: rerun with possibly changed $p (if not it returns the same as above). XXX: check for varuable change instead? B)
  pvinfo=($( pvs --noheadings -o pv_name,vg_name | grep $p ))
  mpath=${pvinfo[0]}
  vgroup=${pvinfo[1]}
  pvresize ${mpath}
  # this last bit...needs work.
  #lvextend -l +100%FREE /dev/mapper/<volume>
  lvcount=$( vgs --noheadings -o lv_count "${vgroup}" )
  [ $lvcount -gt 1 ] && { echo "error: multiple disks in VG ${vgroup} - don't know which one to lvextend and resize - needs manual intervention"; continue; }
  #lvol=$( lvs --noheadings -o lv_name "${vgroup}" )
  #lvextend -L +100%FREE /dev/${vgroup}/${lvol}
  lvolpath=$( lvs --noheadings -o lv_path "${vgroup}" )
  lvextend -l +100%FREE ${lvolpath}
  resize4fs ${lvolpath}
done