From ba32ac1a7c643644c0b238fee622c726a0e6df22 Mon Sep 17 00:00:00 2001
From: Abhinandan Prateek <aprateek@apache.org>
Date: Fri, 2 Dec 2016 13:37:47 +0530
Subject: [PATCH] Cloudstack 9586: When using local storage with Xenserver
 prepareTemplate does not work with multiple primary store The race condition
 will happen whenever there are multiple primary storages and the CS tries to
 mount the secondary store to xenserver host simultaneously. Due to
 synchronised block one mount will be successful and other thread will get the
 already mounted SR. Without the fix the two thread will try to mount it
 parallely and one will fail on Xenserver.

---
 .../Xenserver625StorageProcessor.java         | 45 +++++++------------
 1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/Xenserver625StorageProcessor.java b/plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/Xenserver625StorageProcessor.java
index e58bade2c4e..b07487ba541 100644
--- a/plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/Xenserver625StorageProcessor.java
+++ b/plugins/hypervisors/xenserver/src/com/cloud/hypervisor/xenserver/resource/Xenserver625StorageProcessor.java
@@ -101,35 +101,24 @@ public class Xenserver625StorageProcessor extends XenServerStorageProcessor {
 
         try {
             final String srname = hypervisorResource.getHost().getUuid() + path.trim();
-
-            final Set<SR> srs = SR.getByNameLabel(conn, srname);
-
-            if (srs != null && !srs.isEmpty()) {
-                return srs.iterator().next();
+            synchronized (srname.intern()) {
+                final Set<SR> srs = SR.getByNameLabel(conn, srname);
+                if (srs != null && !srs.isEmpty()) {
+                    return srs.iterator().next();
+                }
+                final Map<String, String> smConfig = new HashMap<String, String>();
+                final Host host = Host.getByUuid(conn, hypervisorResource.getHost().getUuid());
+                final String uuid = UUID.randomUUID().toString();
+                sr = SR.introduce(conn, uuid, srname, srname, "file", "file", false, smConfig);
+                final PBD.Record record = new PBD.Record();
+                record.host = host;
+                record.SR = sr;
+                smConfig.put("location", path);
+                record.deviceConfig = smConfig;
+                pbd = PBD.create(conn, record);
+                pbd.plug(conn);
+                sr.scan(conn);
             }
-
-            final Map<String, String> smConfig = new HashMap<String, String>();
-
-            final Host host = Host.getByUuid(conn, hypervisorResource.getHost().getUuid());
-            final String uuid = UUID.randomUUID().toString();
-
-            sr = SR.introduce(conn, uuid, srname, srname, "file", "file", false, smConfig);
-
-            final PBD.Record record = new PBD.Record();
-
-            record.host = host;
-            record.SR = sr;
-
-            smConfig.put("location", path);
-
-            record.deviceConfig = smConfig;
-
-            pbd = PBD.create(conn, record);
-
-            pbd.plug(conn);
-
-            sr.scan(conn);
-
             return sr;
         } catch (final Exception ex) {
             try {