<fix>[storage]: return defensive copy from getPreferBackupStorageTypes

Resolves: ZSTAC-80789

Change-Id: I2b2d3ce68970c094ab5ba681bcb726b037e0c327

Author: MaJin1996

plugin/expon/src/main/java/org/zstack/expon/ExponStorageFactory.java

@@ -8,6 +8,7 @@
 import org.zstack.header.volume.VolumeInventory;
 import org.zstack.header.volume.VolumeProtocol;
 
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
@@ -48,7 +49,7 @@ public String getIdentity() {
 
     @Override
     public List<String> getPreferBackupStorageTypes() {
-        return preferBackupStorageTypes;
+        return new ArrayList<>(preferBackupStorageTypes);
     }
 
     public void setPreferBackupStorageTypes(List<String> preferBackupStorageTypes) {

plugin/xinfini/src/main/java/org/zstack/xinfini/XInfiniStorageFactory.java

@@ -11,6 +11,7 @@
 import org.zstack.header.xinfini.XInfiniConstants;
 import org.zstack.storage.addon.primary.ExternalPrimaryStorageFactory;
 
+import java.util.ArrayList;
 import java.util.LinkedHashMap;
 import java.util.List;
 
@@ -55,7 +56,7 @@ public String getIdentity() {
 
     @Override
     public List<String> getPreferBackupStorageTypes() {
-        return preferBackupStorageTypes;
+        return new ArrayList<>(preferBackupStorageTypes);
     }
 
     public void setPreferBackupStorageTypes(List<String> preferBackupStorageTypes) {

plugin/zbs/src/main/java/org/zstack/storage/zbs/ZbsStorageFactory.java

@@ -11,6 +11,7 @@
 import org.zstack.utils.ssh.Ssh;
 import org.zstack.utils.ssh.SshResult;
 
+import java.util.ArrayList;
 import java.util.List;
 
 import static org.zstack.core.Platform.operr;
@@ -93,7 +94,7 @@ public void setPreferBackupStorageTypes(List<String> preferBackupStorageTypes) {
 
     @Override
     public List<String> getPreferBackupStorageTypes() {
-        return preferBackupStorageTypes;
+        return new ArrayList<>(preferBackupStorageTypes);
     }
 
     @Override