Fix NPE when Volume exists on secondary store but doesn't have a download URL (#4530)

Co-authored-by: Pearl Dsilva <[email protected]>

Author: Pearl1594

server/src/main/java/com/cloud/storage/VolumeApiServiceImpl.java

@@ -2881,8 +2881,12 @@ private Optional<String> setExtractVolumeSearchCriteria(SearchCriteria<VolumeDat
         } else if (volumeStoreRef != null) {
             s_logger.debug("volume " + volumeId + " is already installed on secondary storage, install path is " +
                     volumeStoreRef.getInstallPath());
+            VolumeInfo destVol = volFactory.getVolume(volumeId, DataStoreRole.Image);
+            if (destVol == null) {
+                throw new CloudRuntimeException("Failed to find the volume on a secondary store");
+            }
             ImageStoreEntity secStore = (ImageStoreEntity) dataStoreMgr.getDataStore(volumeStoreRef.getDataStoreId(), DataStoreRole.Image);
-            String extractUrl = secStore.createEntityExtractUrl(volumeStoreRef.getInstallPath(), volume.getFormat(), null);
+            String extractUrl = secStore.createEntityExtractUrl(volumeStoreRef.getInstallPath(), volume.getFormat(), destVol);
             volumeStoreRef = _volumeStoreDao.findByVolume(volumeId);
             volumeStoreRef.setExtractUrl(extractUrl);
             volumeStoreRef.setExtractUrlCreated(DateUtil.now());