shellcript to mount/unmount VM images containing LVM volumes

mountimage.sh

#!/bin/sh

NAME=$1

if [ "$NAME" == "" ]; then
  echo "usage: $0 <vmname>"
  exit 1;
fi

MYSELF=$( hostname -s )

if [ "$MYSELF" == "$NAME" ]; then
  echo "BAD IDEA: cannot mount $NAME image inside it's VM. try on another host"
  exit 1;
fi

# path to image file
IMGFILE="/backup/host/$NAME/$NAME.raw"

# loopback mount
echo -n "mount loop device: "
losetup -f $IMGFILE

LOOPDEV=$( losetup -j $IMGFILE | awk 'BEGIN {FS=":" } ; { print $1; }' | head -1 )

echo "$LOOPDEV"

echo "adding device maps"
kpartx -av $LOOPDEV

echo "activate volume group vg_$NAME"
vgscan
vgchange -ay vg_$NAME

MOUNTPOINT="/mnt/$NAME"
echo "mount image to $MOUNTPOINT"
mkdir -p $MOUNTPOINT
mount -oro /dev/vg_$NAME/lv_root $MOUNTPOINT

echo ""
echo "press ENTER to reverse process and unmount"
echo "do not forget to cease all file access to mountpoint first!"
echo ""
read


echo "unmounting..."
umount $MOUNTPOINT

echo "disable vg"
# disable volume group
vgchange -an "vg_$NAME"

echo "remove device maps"
# unmap partitions
kpartx -dv $LOOPDEV

echo "detach loopback"
losetup -d $LOOPDEV

echo "done."

probably can be simplified with the partscan option of losetup

losetup --partscan