From de258066eafa7a2c3a42ef88e2c7657ae95d1e99 Mon Sep 17 00:00:00 2001
From: David Vossel <dvossel@redhat.com>
Date: Tue, 16 Jul 2013 18:29:42 -0500
Subject: [PATCH] Low: LVM: Detect duplicate resources with the same volgrpname
 name when using exclusive activation with tags.

For exclusive activation with tags, we already detect
if the resource is a clone and prevent the LVM resource
from activating.  This check goes a step further and
detects if there is another primitive attempting to access
the same volume group in pacemaker's configuraiton. This
check is ignored if pacemaker is not in use, allowing this
agent to continue to be portable to other cluster managers
in the future.

This patch also re-words the 'exclusive' option's documentation
in order to clarify how volume_list filtering works.

Resolves: rhbz#984054
---
 heartbeat/LVM | 32 +++++++++++++++++++++++++++++---
 1 file changed, 29 insertions(+), 3 deletions(-)

diff --git a/heartbeat/LVM b/heartbeat/LVM
index 0ff6ba7..27315df 100755
--- a/heartbeat/LVM
+++ b/heartbeat/LVM
@@ -80,9 +80,17 @@ The name of volume group.
 If set, the volume group will be activated exclusively.  This option works one of
 two ways.  If the volume group has the cluster attribute set, then the volume group
 will be activated exclusively using clvmd across the cluster.  If the cluster attribute
-is not set, the volume group will be activated exclusively using a tag and the volume_list 
-filter. When the tag option is in use, the volume_list in lvm.con must be initialized. This 
-can be as simple as setting 'volume_list = []' depending on your setup.
+is not set, the volume group will be activated exclusively through the use of the 
+volume_list filter in lvm.conf. In the filter scenario, the LVM agent verifies
+that pacemaker's configuration will result in the volume group only being active on a 
+single node in the cluster and that the local node's volume_list filter will prevent 
+the volume group from activating outside of the resource agent.  On activation this 
+agent claims the volume group through the use of a unique tag, and then overrides the 
+volume_list field in a way that allows the volume group to be activated only by the 
+agent.  To use exclusive activation without clvmd, the volume_list in lvm.conf must be 
+initialized. If volume groups exist locally that are not controlled by the cluster, such 
+as the root volume group, make sure those volume groups are listed in the volume_list 
+so they will be allowed to activate on bootup.
 </longdesc>
 <shortdesc lang="en">Exclusive activation</shortdesc>
 <content type="boolean" default="false" />
@@ -191,6 +199,24 @@ verify_tags_environment()
 		return $OCF_ERR_GENERIC
 	fi
 
+
+	##
+	# Verify that if this agent is being used in a Pacemaker cluster,
+	# no other LVM agents in the cib contain the same volgrpname
+	##
+	if have_binary "cibadmin" ; then
+		# This detects if there is any other LVM primitive (besides this instance) that
+		# is already assigned the same volume group. If so, do not activate this instance. 
+		cibadmin --local -Q --xpath '//primitive[@type="LVM"][@id!="'${OCF_RESOURCE_INSTANCE}'"]//instance_attributes//nvpair[@name="volgrpname"][@value="'${OCF_RESKEY_volgrpname}'"]' \
+			> /dev/null 2>&1
+
+		if [ $? -eq 0 ]; then
+			ocf_log err "LVM:  Improper setup detected"
+			ocf_log err "Duplicate LVM resource controlling vg '$OCF_RESKEY_volgrpname' detected in cib configuration. Can not activate exclusively"
+			return $OCF_ERR_GENERIC
+		fi
+
+	fi
 	return $OCF_SUCCESS
 }
 
-- 
1.8.1