HDFS-13065. TestErasureCodingMultipleRacks#testSkewedRack3 is failing. Contributed by Gabor Bota.

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/TestErasureCodingMultipleRacks.java

@@ -21,6 +21,7 @@ import org.apache.hadoop.conf.Configuration;
 import org.apache.hadoop.fs.BlockLocation;
 import org.apache.hadoop.fs.Path;
 import org.apache.hadoop.hdfs.protocol.ErasureCodingPolicy;
+import org.apache.hadoop.hdfs.protocol.ExtendedBlock;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicy;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyDefault;
 import org.apache.hadoop.hdfs.server.blockmanagement.BlockPlacementPolicyRackFaultTolerant;
@@ -163,7 +164,8 @@ public class TestErasureCodingMultipleRacks {
     // Create enough extra DNs on the 2 racks to test even placement.
     // Desired placement is parityUnits replicas on the 2 racks, and 1 replica
     // on the rest of the racks (which only have 1 DN)
-    setupCluster(dataUnits + parityUnits * 4, dataUnits - parityUnits + 2,
+    int numRacks = dataUnits - parityUnits + 2;
+    setupCluster(dataUnits + parityUnits * 4, numRacks,
         dataUnits - parityUnits);
 
     final int filesize = ecPolicy.getNumDataUnits() * ecPolicy.getCellSize();
@@ -173,6 +175,10 @@ public class TestErasureCodingMultipleRacks {
       final Path path = new Path("/testfile" + i);
       LOG.info("Writing file " + path);
       DFSTestUtil.writeFile(dfs, path, contents);
+      ExtendedBlock extendedBlock = DFSTestUtil.getFirstBlock(dfs, path);
+      // Wait for replication to finish before testing
+      DFSTestUtil.waitForReplication(cluster, extendedBlock, numRacks,
+          ecPolicy.getNumDataUnits() + ecPolicy.getNumParityUnits(), 0);
       BlockLocation[] blocks =
           dfs.getFileBlockLocations(path, 0, Long.MAX_VALUE);
       assertEquals(ecPolicy.getNumDataUnits() + ecPolicy.getNumParityUnits(),