HDFS-17465. RBF: Use ProportionRouterRpcFairnessPolicyController get “'ava.Lang. Error: Maximum permit count exceeded' (#6727)

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/fairness/ProportionRouterRpcFairnessPolicyController.java

@@ -93,7 +93,8 @@ public class ProportionRouterRpcFairnessPolicyController extends
   public void releasePermit(String nsId) {
     if (contains(nsId)) {
       super.releasePermit(nsId);
+    } else {
+      super.releasePermit(DEFAULT_NS);
     }
-    super.releasePermit(DEFAULT_NS);
   }
 }