diff --git a/heartbeat/LVM b/heartbeat/LVM
index 998c66a5d..906c55ddc 100755
--- a/heartbeat/LVM
+++ b/heartbeat/LVM
@@ -1,364 +1,402 @@
 #!/bin/sh
 #
 # 
 # LVM
 #
 # Description:	Manages an LVM volume as an HA resource
 #
 #
 # Author:	Alan Robertson
 # Support:	linux-ha@lists.linux-ha.org
 # License:	GNU General Public License (GPL)
 # Copyright:	(C) 2002 - 2005 International Business Machines, Inc.
 #
 #	This code significantly inspired by the LVM resource
 #	in FailSafe by Lars Marowsky-Bree
 #
 #
 # An example usage in /etc/ha.d/haresources: 
 #			 node1	10.0.0.170 ServeRAID::1::1 LVM::myvolname
 #
 # See usage() function below for more details...
 #
 #		OCF parameters are as below:
 #		OCF_RESKEY_volgrpname
 #		
 #######################################################################
 # Initialization:
 
 : ${OCF_FUNCTIONS_DIR=${OCF_ROOT}/lib/heartbeat}
 . ${OCF_FUNCTIONS_DIR}/ocf-shellfuncs
 
 #######################################################################
 
 
 usage() {
 	methods=`LVM_methods`
 	methods=`echo $methods | tr ' ' '|'`
 	cat <<EOF
 	usage: $0 $methods
 
 	$0 manages an	Linux Volume Manager volume (LVM) as an HA resource
 
 	The 'start' operation brings the given volume online
 	The 'stop' operation takes the given volume offline
 	The 'status' operation reports whether the volume is available
 	The 'monitor' operation reports whether the volume seems present
 	The 'validate-all' operation checks whether the OCF parameters are valid
 	The 'meta-data' operation show meta data 
 	The 'methods' operation reports on the methods $0 supports
 
 EOF
 }
 
 meta_data() {
 	cat <<EOF
 <?xml version="1.0"?>
 <!DOCTYPE resource-agent SYSTEM "ra-api-1.dtd">
 <resource-agent name="LVM">
 <version>1.0</version>
 
 <longdesc lang="en">
 Resource script for LVM. It manages an Linux Volume Manager volume (LVM) 
 as an HA resource. 
 </longdesc>
 <shortdesc lang="en">Controls the availability of an LVM Volume Group</shortdesc>
 
 <parameters>
 <parameter name="volgrpname" unique="0" required="1">
 <longdesc lang="en">
 The name of volume group.
 </longdesc>
 <shortdesc lang="en">Volume group name</shortdesc>
 <content type="string" default="" />
 </parameter>
 <parameter name="exclusive" unique="0" required="0">
 <longdesc lang="en">
 If set, the volume group will be activated exclusively.
 </longdesc>
 <shortdesc lang="en">Exclusive activation</shortdesc>
 <content type="boolean" default="false" />
 </parameter>
 
 <parameter name="partial_activation" unique="0" required="0">
 <longdesc lang="en">
 If set, the volume group will be activated even only partial of the physical
 volumes available. It helps to set to true, when you are using mirroring
 logical volumes.
 </longdesc>
 <shortdesc lang="en">Activate VG even with partial PV only</shortdesc>
 <content type="string" default="false" />
 </parameter>
 
 </parameters>
 
 <actions>
 <action name="start" timeout="30" />
 <action name="stop" timeout="30" />
 <action name="status" timeout="30" />
 <action name="monitor" depth="0" timeout="30" interval="10" />
 <action name="methods" timeout="5" />
 <action name="meta-data" timeout="5" />
 <action name="validate-all" timeout="5" />
 </actions>
 </resource-agent>
 EOF
 }
 
 #
 # methods: What methods/operations do we support?
 #
 LVM_methods() {
 	cat <<EOF
 	start
 	stop
 	status
 	monitor
 	methods
 	validate-all
 	meta-data
 	usage
 EOF
 }
 
 #
 #	Return LVM status (silently)
 #
 LVM_status() {
 	local rc=1
 	loglevel="debug"
 
 	# Set the log level of the error message
 	if [ "X${2}" = "X" ]; then
 		loglevel="err"
 		if ocf_is_probe; then
 			loglevel="warn"
 		else 
 			if [ ${OP_METHOD} = "stop" ]; then
 				loglevel="info"
 			fi
 		fi
 	fi
 	
 	if [ -d /dev/$1 ]; then
 		test "`cd /dev/$1 && ls`" != ""
 		rc=$?
 		if [ $rc -ne 0 ]; then
 			ocf_log err "VG $1 with no logical volumes is not supported by this RA!"
 		fi
 	fi
 
 	if [ $rc -ne 0 ]; then
 		ocf_log $loglevel "LVM Volume $1 is not available (stopped)"
 	fi
 
 	if [ "X${2}" = "X" ]; then
 		# status call return
 		return $rc
 	fi
 
 	# Report on LVM volume status to stdout...
 	if [ $rc -eq 0 ]; then
 		echo "Volume $1 is available (running)"
 	else
 		echo "Volume $1 is not available (stopped)"
 	fi
 	return $rc
 }
 
 #
 #	Monitor the volume - does it really seem to be working?
 #
 #
 LVM_monitor() {
 	if
 		LVM_status $1
 	then
 		: OK
 	else
 		ocf_log info "LVM Volume $1 is offline"
 		return $OCF_NOT_RUNNING
 	fi
 
 	return $OCF_SUCCESS
 }
 
 #
 #	Enable LVM volume
 #
 LVM_start() {
 	local vgchange_options
 	local active_mode
 
 	# TODO: This MUST run vgimport as well
 
 	ocf_log info "Activating volume group $1"
 
 	if [ "$LVM_MAJOR" -eq "1" ]; then
 		ocf_run vgscan $1
 	else
 		ocf_run vgscan
 	fi
 
 	active_mode="ly"
 	if ocf_is_true "$OCF_RESKEY_exclusive" ; then
 		active_mode="ey"
 	fi
 	vgchange_options="-a $active_mode"
 
 	if ocf_is_true "$OCF_RESKEY_partial_activation" ; then
 		vgchange_options="$vgchange_options --partial"
 	fi
 
 	# for clones (clustered volume groups), we'll also have to force
 	# monitoring, even if disabled in lvm.conf.
 	if ocf_is_clone; then
 		vgchange_options="$vgchange_options --monitor y"
 	fi
 
 	ocf_run vgchange $vgchange_options $1 || return $OCF_ERR_GENERIC
 
 	if LVM_status $1; then
 		: OK Volume $1 activated just fine!
 		return $OCF_SUCCESS 
 	else
 		ocf_log err "LVM: $1 did not activate correctly"
 		return $OCF_NOT_RUNNING
 	fi
 }
 
 #
 #	Disable the LVM volume
 #
 LVM_stop() {
 
 	vgdisplay "$1" 2>&1 | grep 'Volume group .* not found' >/dev/null && {
 		ocf_log info "Volume group $1 not found"
 		return $OCF_SUCCESS
 	}
 	ocf_log info "Deactivating volume group $1"
 	ocf_run vgchange -a ln $1 || return $OCF_ERR_GENERIC
 
 	if
 		LVM_status $1
 	then
 		ocf_log err "LVM: $1 did not stop correctly"
 		return $OCF_ERR_GENERIC 
 	fi
 
 	# TODO: This MUST run vgexport as well
 
 	return $OCF_SUCCESS
 }
 
 #
 #	Check whether the OCF instance parameters are valid
 #
 LVM_validate_all() {
 	check_binary $AWK
 
-#	Off-the-shelf tests...
+	##
+	# Off-the-shelf tests...
+	##
 	VGOUT=`vgck ${VOLUME} 2>&1`
-	
 	if [ $? -ne 0 ]; then
 		ocf_log err "Volume group [$VOLUME] does not exist or contains error! ${VGOUT}"
 		exit $OCF_ERR_GENERIC
 	fi
 
-#	Double-check
-	if 
-		[ "$LVM_MAJOR" -eq "1" ]
-	then
+	##
+	# Does the Volume Group exist?
+	##
+	if [ "$LVM_MAJOR" = "1" ]; then
 		VGOUT=`vgdisplay ${VOLUME} 2>&1`
 	else
 		VGOUT=`vgdisplay -v ${VOLUME} 2>&1`
 	fi
-
 	if [ $? -ne 0 ]; then
 		ocf_log err "Volume group [$VOLUME] does not exist or contains error! ${VGOUT}"
 		exit $OCF_ERR_GENERIC
 	fi
 
+	##
+	# If exclusive activation is not enabled, then
+	# further checking of proper setup is not necessary
+	##
+	if ! ocf_is_true "$OCF_RESKEY_exclusive"; then
+		return $OCF_SUCCESS;
+	fi
+
+	##
+	# Having cloned lvm resources with exclusive vg activation makes no sense at all.
+	##
+	if ocf_is_clone; then
+		ocf_log_err "cloned lvm resources can not be activated exclusively"
+		exit $OCF_ERR_CONFIGURED
+	fi
+
+	##
+	# Make sure the cluster attribute is set and clvmd is up when exclusive
+	# activation is enabled. Otherwise we can't exclusively activate the volume group.
+	##
+	case $(vgs -o attr --noheadings $OCF_RESKEY_volgrpname 2>/dev/null | tr -d ' ') in
+	?????c*)
+		# Is clvmd running?
+		if ! ps -C clvmd > /dev/null 2>&1; then
+			ocf_log err "$OCF_RESKEY_volgrpname has the cluster attribute set, but 'clvmd' is not running"
+			exit $OCF_ERR_GENERIC
+		fi
+		return $OCF_SUCCESS
+		;;
+	*)
+		ocf_log err "Unable to exclusively activate $OCF_RESKEY_volgrpname becaues it is not a clusted volume group"
+		exit $OCF_ERR_GENERIC
+		;;
+	esac
+
 	return $OCF_SUCCESS
 }
+
 #
 #	'main' starts here...
 #
 
 if
 	[ $# -ne 1 ]
 then
 	usage
 	exit $OCF_ERR_ARGS 
 fi
 
 case $1 in
 	meta-data)	meta_data
 		exit $OCF_SUCCESS;;
 
 	methods)	LVM_methods
 		exit $?;;
 
 	usage)	usage
 		exit $OCF_SUCCESS;;
 	*)		;;
 esac
 
 if 
 	[ -z "$OCF_RESKEY_volgrpname" ]
 then
 	ocf_log err "You must identify the volume group name!"
 	exit $OCF_ERR_CONFIGURED 
 fi
 
 # Get the LVM version number, for this to work we assume(thanks to panjiam):
 # 
 # LVM1 outputs like this
 #
 #	# vgchange --version
 #	vgchange: Logical Volume Manager 1.0.3
 #	Heinz Mauelshagen, Sistina Software	19/02/2002 (IOP 10)
 #
 # LVM2 and higher versions output in this format
 #
 #	# vgchange --version
 #	LVM version:		 2.00.15 (2004-04-19)
 #	Library version: 1.00.09-ioctl (2004-03-31)
 #	Driver version:	4.1.0
 
 LVM_VERSION=`vgchange --version 2>&1 | \
 	$AWK '/Logical Volume Manager/ {print $5"\n"; exit; }
 			 /LVM version:/ {printf $3"\n"; exit;}'`
 rc=$?
 
 if
 	( [ $rc -ne 0 ] || [ -z "$LVM_VERSION" ] )
 then
 	ocf_log err "LVM: $1 could not determine LVM version. Try 'vgchange --version' manually and modify $0 ?"
 	exit $OCF_ERR_INSTALLED
 fi
 LVM_MAJOR="${LVM_VERSION%%.*}"
 
 VOLUME=$OCF_RESKEY_volgrpname
 OP_METHOD=$1
 # What kind of method was invoked?
 case "$1" in
 
-	start)	LVM_start $VOLUME
+	start)
+		LVM_validate_all
+		LVM_start $VOLUME
 		exit $?;;
 
 	stop)	LVM_stop $VOLUME
 		exit $?;;
 
 	status)	LVM_status $VOLUME $1
 		exit $?;;
 
 	monitor)	LVM_monitor $VOLUME
 		exit $?;;
 
 	validate-all)	LVM_validate_all
 		;;
 
 	*)		usage
 		exit $OCF_ERR_UNIMPLEMENTED;;
 esac