NodeList nodes = (NodeList) expr.evaluate(doc, XPathConstants.NODESET);
String diskFileName = nodes.item(0).getNodeValue();
StorageVol storageVol = client.storageVolLookupByPath(diskFileName);
// cloning volume
String poolName = storageVol.storagePoolLookupByVolume().getName();
StoragePool storagePool = client.storagePoolLookupByName(poolName);
StorageVol clonedVol = null;
boolean cloned = false;
int retry = 0;
while (!cloned && retry < 10) {