HDFS-15092. TestRedudantBlocks#testProcessOverReplicatedAndRedudantBlock sometimes fails. Contributed by Fei Hui.

(cherry picked from commit 8cfc3673dcbf1901ca6fad11b5c996e54e32ed6b)
(cherry picked from commit 86028d975c050c5d2a4f3fde22cba9b867bb3f03)

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/namenode/TestRedudantBlocks.java

@@ -35,8 +35,10 @@ import org.apache.hadoop.hdfs.protocol.LocatedBlock;
 import org.apache.hadoop.hdfs.protocol.LocatedBlocks;
 import org.apache.hadoop.hdfs.protocol.LocatedStripedBlock;
 import org.apache.hadoop.hdfs.protocol.SystemErasureCodingPolicies;
+import org.apache.hadoop.hdfs.server.blockmanagement.BlockInfoStriped;
 import org.apache.hadoop.hdfs.server.datanode.SimulatedFSDataset;
 import org.apache.hadoop.hdfs.util.StripedBlockUtil;
+import org.apache.hadoop.test.GenericTestUtils;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Test;
@@ -108,18 +110,26 @@ public class TestRedudantBlocks {
     blk.setBlockId(groupId + 2);
     cluster.injectBlocks(i, Arrays.asList(blk), bpid);
 
+    BlockInfoStriped blockInfo =
+        (BlockInfoStriped)cluster.getNamesystem().getBlockManager()
+            .getStoredBlock(new Block(groupId));
     // update blocksMap
     cluster.triggerBlockReports();
     // delete redundant block
     cluster.triggerHeartbeats();
     //wait for IBR
-    Thread.sleep(1100);
+    GenericTestUtils.waitFor(
+        () -> cluster.getNamesystem().getBlockManager()
+            .countNodes(blockInfo).liveReplicas() >= groupSize -1,
+        500, 10000);
 
     // trigger reconstruction
     cluster.triggerHeartbeats();
-
     //wait for IBR
-    Thread.sleep(1100);
+    GenericTestUtils.waitFor(
+        () -> cluster.getNamesystem().getBlockManager()
+            .countNodes(blockInfo).liveReplicas() >= groupSize,
+        500, 10000);
 
     HashSet<Long> blockIdsSet = new HashSet<Long>();