#!/bin/bash
#################################################################################
# Copyright 2021 Salvatore Costantino                                           #
# ha@pulsesupply.com                                                            #
#                                                                               #
#                                                                               #
#    replug_pbd is free software: you can redistribute it and/or modify         #
#    it under the terms of the GNU General Public License as published by       #
#    the Free Software Foundation, either version 3 of the License, or          #
#    (at your option) any later version.                                        #
#                                                                               #
#    replug_pbd is distributed in the hope that it will be useful,              #
#    but WITHOUT ANY WARRANTY; without even the implied warranty of             #
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the              #
#    GNU General Public License for more details.                               #
#                                                                               #
#    You should have received a copy of the GNU General Public License          #
#    along with replug_pbd.  If not, see <http://www.gnu.org/licenses/>.        #
#                                                                               #
#################################################################################

STATE=$(/bin/cat /etc/xensource/pool.conf)
if [[ $STATE == slave* ]]
then
        # Make sure master is responding before making calls to xe
        MASTER_IP=`cat /etc/xensource/pool.conf | awk -F ":" '{print $2}'`
        ping -c 1 -w 1 $MASTER_IP > /dev/null
        if [ $? -ne 0 ]
        then
                echo "Pool Master $MASTER_IP not responding - replug_pbd exiting"
                exit 1
        fi
fi

HOST_NAME=$(hostname)
THIS_HOST_UUID=$(xe host-list name-label=$HOST_NAME --minimal)
ISCSI_SR_LIST=$(xe sr-list type=lvmoiscsi --minimal | awk -F "," '{$1=$1}1')
VG_LIST=$(vgscan | grep -v Reading | awk -F "VG_XenStorage-" {'print $2'} | awk -F ""\" {'print $1'})

if [ "$1" != "--silent" ]
then
	echo "replug_pbd Version 1.3: Replugs a PBD where a VG is not scanned. Attempts to resolve"
	echo "XenServer errors: SR_BACKEND_FAILURE_40 or SR_BACKEND_FAILURE_46 or VDI is not available"
	echo "Currently works with iSCSI SRs."
	echo

	echo -e "\r"
	echo "Hostname Found:          $HOST_NAME"
	echo "Host UUID Found:         $THIS_HOST_UUID"
	echo "iSCSI SR(s) Found:       "$ISCSI_SR_LIST""
	echo -e "Volume Groups Found:     "$VG_LIST"\r\n"
fi

#######################################
# Function replug_pbd unplugs and then
# plugs the PBD for the passed in
# SR UUID and Host UUID
#
# Ars passed in:
# arg1 = SR UUID
# arg2 = Host UUID
#
# Returns 0 on success
# Returns 1 on failure/error
########################################
function replug_pbd ()
{
PBD=$(xe pbd-list sr-uuid=$1 host-uuid=$2 --minimal)
if [ $? -eq 0 ] && [[ -n ${PBD} ]]
then
	echo "replugging PBD: $PBD"
	xe pbd-unplug uuid=$PBD && xe pbd-plug uuid=$PBD
	if [ $? -eq 0 ]
	then
		echo "Successfully re-plugged PBD: $PBD"
		return 0
	else
		echo "Failed to re-plug PBD: $PBD"
		return 1
	fi
else
	echo "Failed to locate PBD for SR: $1 on HOST: $2"
	return 1
fi
} #End Function replug_pbd

#############################################
# Make sure each iscsi SR has a corresponding
# VG found, else re-plug the PBD
#############################################
for iscsi_sr in ${ISCSI_SR_LIST[@]}
do
	echo "Scanning for Volume Group -> iscsi-sr: $iscsi_sr"
	for vg in ${VG_LIST[@]}
	do
		if [ "$vg" = "$iscsi_sr" ]
		then
			echo "Volume Group for iSCSI-SR found OK: $vg"
			SR_OK=1
			break
		else
			SR_OK=0
		fi
	done

	if [ "$SR_OK" = "0" ]
	then
		echo "Volume Group for iSCSI-SR $iscsi_sr not found - attemping to re-plug"
		replug_pbd $iscsi_sr $THIS_HOST_UUID
		if [ $? -eq 1 ]
		then
			RETURN=1
		fi
	fi
done

if [ "$RETURN" = "1" ]
then
	exit 1
else
	exit 0
fi