update pool setting when modified

Author: Pearl Dsilva

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

@@ -72,7 +72,10 @@ private StorageAdaptor getStorageAdaptor(StoragePoolType type) {
 
     private void addStoragePool(String uuid, StoragePoolInformation pool) {
         synchronized (_storagePools) {
-            if (!_storagePools.containsKey(uuid)) {
+            // Insert on first registration; on subsequent calls (e.g. ModifyStoragePoolCommand)
+            // overwrite when new details are present so dynamic config changes
+            // (e.g. clvm.secure.zero.fill) are not silently dropped.
+            if (!_storagePools.containsKey(uuid) || MapUtils.isNotEmpty(pool.getDetails())) {
                 _storagePools.put(uuid, pool);
             }
         }
@@ -327,6 +330,10 @@ private void updatePoolTypeIfApplicable(LibvirtStoragePool libvirtPool, KVMStora
      */
     private void addPoolDetails(String uuid, LibvirtStoragePool pool) {
         StoragePoolInformation storagePoolInformation = _storagePools.get(uuid);
+        if (storagePoolInformation == null) {
+            logger.warn("No cached StoragePoolInformation found for pool UUID {}, pool details will not be set.", uuid);
+            return;
+        }
         Map<String, String> details = storagePoolInformation.getDetails();
 
         if (MapUtils.isNotEmpty(details)) {