storagefile: Add externalDataStore member

Add the plumbing to track a externalDataStoreRaw as a virStorageSource
Reviewed-by: NDaniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: NMichal Privoznik <mprivozn@redhat.com>
Signed-off-by: NCole Robinson <crobinso@redhat.com>

src/util/virstoragefile.c

@@ -2340,6 +2340,12 @@ virStorageSourceCopy(const virStorageSource *src,
             return NULL;
     }
 
+    if (src->externalDataStore) {
+        if (!(def->externalDataStore = virStorageSourceCopy(src->externalDataStore,
+                                                            true)))
+            return NULL;
+    }
+
     VIR_STEAL_PTR(ret, def);
     return ret;
 }
@@ -2561,6 +2567,9 @@ virStorageSourceClear(virStorageSourcePtr def)
     VIR_FREE(def->timestamps);
     VIR_FREE(def->externalDataStoreRaw);
 
+    virObjectUnref(def->externalDataStore);
+    def->externalDataStore = NULL;
+
     virStorageNetHostDefFree(def->nhosts, def->hosts);
     virStorageAuthDefFree(def->auth);
     virObjectUnref(def->privateData);

src/util/virstoragefile.h

@@ -292,6 +292,9 @@ struct _virStorageSource {
     /* backing chain of the storage source */
     virStorageSourcePtr backingStore;
 
+    /* external data store storage source */
+    virStorageSourcePtr externalDataStore;
+
     /* metadata for storage driver access to remote and local volumes */
     virStorageDriverDataPtr drv;