HDFS-15297. TestNNHandlesBlockReportPerStorage::blockReport_02 fails intermittently. Contributed by Ayush Saxena

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/BlockReportTestBase.java

@@ -37,7 +37,6 @@ import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
-import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 
 import org.slf4j.Logger;
@@ -320,7 +319,7 @@ public abstract class BlockReportTestBase {
       }
     }
 
-    waitTil(TimeUnit.SECONDS.toMillis(DN_RESCAN_EXTRA_WAIT));
+    DataNodeTestUtils.runDirectoryScanner(dn0);
 
     // all blocks belong to the same file, hence same BP
     String poolId = cluster.getNamesystem().getBlockPoolId();