HDFS-17204. EC: Reduce unnecessary log when processing excess redundancy. (#6107). Contributed by Shuyan Zhang.

Reviewed-by: Haiyang Hu <haiyang.hu@shopee.com>
Signed-off-by: He Xiaoqiao <hexiaoqiao@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/blockmanagement/BlockManager.java

@@ -4201,6 +4201,12 @@ public class BlockManager implements BlockStatsMXBean {
       storage2index.put(storage, index);
     }
 
+    if (duplicated.isEmpty()) {
+      LOG.debug("Found no duplicated internal blocks for {}. Maybe it's " +
+          "because there are stale storages.", storedBlock);
+      return;
+    }
+
     // use delHint only if delHint is duplicated
     final DatanodeStorageInfo delStorageHint =
         DatanodeStorageInfo.getDatanodeStorageInfo(nonExcess, delNodeHint);