#!/bin/bash
#
# Copyright (c) 2016 Wind River Systems, Inc.
#
# SPDX-License-Identifier: Apache-2.0
#


# This script is intended to clean up the LVM thin pool used by
# nova-compute.  This is required so that packstack is free to resize the
# instances_lv volume or to switch between volume-backed or image-backed
# instance storage.
#
# It should only run on compute nodes, and it must be run before packstack.

errlog()
{
    logger -t nova_clean_thinpool -p daemon.err "$@"
}


start()
{
    # We expect this as the volume group
    VOL_GROUP="nova-local"

    # We expect this as the thin pool
    THIN_POOL="nova-local-pool"

    # Test if any volume is the thin pool
    lvs -o lv_name --noheadings | grep -e $THIN_POOL
    if [ $? -eq 0 ] ; then
        # Now test if any volumes are in the thin pool
        lvs -o pool_lv --noheadings | grep -e $THIN_POOL
        if [ $? -ne 0 ] ; then
            # Thin pool is present and empty, delete it.
            lvremove -f ${VOL_GROUP}/$THIN_POOL
            if [ $? -ne 0 ] ; then
                errlog "Problem deleting ${VOL_GROUP}/$THIN_POOL"
            fi
        else
            errlog "Not deleting $THIN_POOL because it's not empty."
        fi
    fi
}

stop ()
{
    return
}

case "$1" in
    start)
        start
        ;;
    stop)
        stop
        ;;
    *)
        echo "Usage: $0 {start|stop}"
        exit 1
        ;;
esac

exit 0