fix checkstyle

Author: zhtttylz

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

@@ -166,6 +166,7 @@ private void chooseEvenlyFromRemainingRacks(Node writer,
       List<DatanodeStorageInfo> results, boolean avoidStaleNodes,
       EnumMap<StorageType, Integer> storageTypes, int totalReplicaExpected,
       NotEnoughReplicasException e) throws NotEnoughReplicasException {
+    int numResultsOflastChoose = 0;
     NotEnoughReplicasException lastException = e;
     int bestEffortMaxNodesPerRack = maxNodesPerRack;
     while (results.size() != totalReplicaExpected &&
@@ -181,6 +182,7 @@ private void chooseEvenlyFromRemainingRacks(Node writer,
       LOG.trace("Excluded nodes: {}", excludedNodes);
       LOG.trace("New Excluded nodes: {}", newExcludeNodes);
       final int numOfReplicas = totalReplicaExpected - results.size();
+      numResultsOflastChoose = results.size();
       try {
         chooseOnce(numOfReplicas, writer, newExcludeNodes, blocksize,
             ++bestEffortMaxNodesPerRack, results, avoidStaleNodes,
@@ -190,6 +192,14 @@ private void chooseEvenlyFromRemainingRacks(Node writer,
       } finally {
         excludedNodes.addAll(newExcludeNodes);
       }
+      if (numResultsOflastChoose == results.size()) {
+        Map<String, Integer> nodesPerRack = new HashMap<>();
+        for (DatanodeStorageInfo dsInfo : results) {
+          String rackName = dsInfo.getDatanodeDescriptor().getNetworkLocation();
+          nodesPerRack.merge(rackName, 1, Integer::sum);
+        }
+        bestEffortMaxNodesPerRack = Collections.max(nodesPerRack.values());
+      }
     }
 
     if (results.size() != totalReplicaExpected) {