Fix volume snapshot in VM with attached ISO (#7037)

Co-authored-by: Stephan Krug <stephan.krug@scclouds.com.br>

Author: stephankruggg

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtDomainXMLParser.java

@@ -121,7 +121,7 @@ public boolean parseDomainXML(String domXML) {
                             }
                             def.defFileBasedDisk(diskFile, diskLabel, DiskDef.DiskBus.valueOf(bus.toUpperCase()), fmt);
                         } else if (device.equalsIgnoreCase("cdrom")) {
-                            def.defISODisk(diskFile , i+1);
+                            def.defISODisk(diskFile, i+1, diskLabel);
                         }
                     } else if (type.equalsIgnoreCase("block")) {
                         def.defBlockBasedDisk(diskDev, diskLabel,

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/resource/LibvirtVMDef.java

@@ -860,17 +860,31 @@ public void defISODisk(String volPath, boolean isUefiEnabled) {
         }
 
         public void defISODisk(String volPath, Integer devId) {
-            if (devId == null) {
+            defISODisk(volPath, devId, null);
+        }
+
+        public void defISODisk(String volPath, Integer devId, String diskLabel) {
+            if (devId == null && StringUtils.isBlank(diskLabel)) {
+                s_logger.debug(String.format("No ID or label informed for volume [%s].", volPath));
                 defISODisk(volPath);
+                return;
+            }
+
+            _diskType = DiskType.FILE;
+            _deviceType = DeviceType.CDROM;
+            _sourcePath = volPath;
+
+            if (StringUtils.isNotBlank(diskLabel)) {
+                s_logger.debug(String.format("Using informed label [%s] for volume [%s].", diskLabel, volPath));
+                _diskLabel = diskLabel;
             } else {
-                _diskType = DiskType.FILE;
-                _deviceType = DeviceType.CDROM;
-                _sourcePath = volPath;
                 _diskLabel = getDevLabel(devId, DiskBus.IDE, true);
-                _diskFmtType = DiskFmtType.RAW;
-                _diskCacheMode = DiskCacheMode.NONE;
-                _bus = DiskBus.IDE;
+                s_logger.debug(String.format("Using device ID [%s] to define the label [%s] for volume [%s].", devId, _diskLabel, volPath));
             }
+
+            _diskFmtType = DiskFmtType.RAW;
+            _diskCacheMode = DiskCacheMode.NONE;
+            _bus = DiskBus.IDE;
         }
 
         public void defISODisk(String volPath, Integer devId,boolean isSecure) {