Comment 1 for bug 177868

To make it even safer one might also check for the existance of /var/lib/partman/devices/$dev/loop

loopfile=$(losetup $device 2>/dev/null|cut -f 3 -d ' ')
loopfile=${loopfile#\(}
loopfile=${loopfile%\)}
[ -z "$loopfile" ] && [ -f loop ] && loopfile=$(cat loop)
if [ -n "$loopfile" ]; then
   if log-output -t partman --pass-stdout mkfs.ext3 -F "$loopfile" >/dev/null; then
       sync
       status=OK
   else
       status=failed
   fi
else
    #run mkfs as usual
fi