Fix in the calculation of a volume's physical size

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

@@ -83,6 +83,10 @@ public VolumeFormat getFormat() {
         return this._volFormat;
     }
 
+    public Long getVolSize() {
+        return _volSize;
+    }
+
     @Override
     public String toString() {
         StringBuilder storageVolBuilder = new StringBuilder();

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

@@ -35,6 +35,26 @@
 public class LibvirtStorageVolumeXMLParser {
     protected Logger logger = LogManager.getLogger(getClass());
 
+    public String getBackingFileNameIfExists(String volXML) {
+        try {
+            DocumentBuilder builder = ParserUtils.getSaferDocumentBuilderFactory().newDocumentBuilder();
+
+            InputSource is = new InputSource();
+            is.setCharacterStream(new StringReader(volXML));
+            Document doc = builder.parse(is);
+
+            Element rootElement = doc.getDocumentElement();
+            Element backingStore = (Element)rootElement.getElementsByTagName("backingStore").item(0);
+            if (backingStore != null) {
+                String[] paths = getTagValue("path", backingStore).split("/");
+                return paths[paths.length-1];
+            }
+        } catch (ParserConfigurationException | SAXException | IOException e) {
+            logger.error(e.toString(), e);
+        }
+        return null;
+    }
+
     public LibvirtStorageVolumeDef parseStorageVolumeXML(String volXML) {
         DocumentBuilder builder;
         try {
@@ -50,6 +70,7 @@ public LibvirtStorageVolumeDef parseStorageVolumeXML(String volXML) {
             Element target = (Element)rootElement.getElementsByTagName("target").item(0);
             String format = getAttrValue("type", "format", target);
             Long capacity = Long.parseLong(getTagValue("capacity", rootElement));
+
             return new LibvirtStorageVolumeDef(VolName, capacity, LibvirtStorageVolumeDef.VolumeFormat.getFormat(format), null, null);
         } catch (ParserConfigurationException e) {
             logger.debug(e.toString());

plugins/hypervisors/kvm/src/main/java/com/cloud/hypervisor/kvm/storage/LibvirtStorageAdaptor.java

@@ -507,6 +507,12 @@ public LibvirtStoragePoolDef getStoragePoolDef(Connect conn, StoragePool pool) t
         return parser.parseStoragePoolXML(poolDefXML);
     }
 
+    public String getBackingFileOfVolumeIfExists(StorageVol vol) throws LibvirtException {
+        String volDefXML = vol.getXMLDesc(0);
+        LibvirtStorageVolumeXMLParser parser = new LibvirtStorageVolumeXMLParser();
+        return parser.getBackingFileNameIfExists(volDefXML);
+    }
+
     public LibvirtStorageVolumeDef getStorageVolumeDef(Connect conn, StorageVol vol) throws LibvirtException {
         String volDefXML = vol.getXMLDesc(0);
         LibvirtStorageVolumeXMLParser parser = new LibvirtStorageVolumeXMLParser();
@@ -657,6 +663,16 @@ public KVMStoragePool getStoragePool(String uuid, boolean refreshInfo) {
         }
     }
 
+    public Long getBackingFileSizes(StoragePool pool, StorageVol vol) throws LibvirtException {
+        long size = vol.getInfo().allocation;
+        String backingFileOfVolumeIfExists = getBackingFileOfVolumeIfExists(vol);
+        if (backingFileOfVolumeIfExists != null) {
+            StorageVol backingFile = getVolume(pool, backingFileOfVolumeIfExists);
+            size += getBackingFileSizes(pool, backingFile);
+        }
+        return size;
+    }
+
     @Override
     public KVMPhysicalDisk getPhysicalDisk(String volumeUuid, KVMStoragePool pool) {
         LibvirtStoragePool libvirtPool = (LibvirtStoragePool)pool;
@@ -665,8 +681,9 @@ public KVMPhysicalDisk getPhysicalDisk(String volumeUuid, KVMStoragePool pool) {
             StorageVol vol = getVolume(libvirtPool.getPool(), volumeUuid);
             KVMPhysicalDisk disk;
             LibvirtStorageVolumeDef voldef = getStorageVolumeDef(libvirtPool.getPool().getConnect(), vol);
+            Long allSizes = getBackingFileSizes(libvirtPool.getPool(), vol);
             disk = new KVMPhysicalDisk(vol.getPath(), vol.getName(), pool);
-            disk.setSize(vol.getInfo().allocation);
+            disk.setSize(allSizes);
             disk.setVirtualSize(vol.getInfo().capacity);
 
             /**