HDFS-16339. Show the threshold when mover threads quota is exceeded (#3689)

Reviewed-by: Viraj Jasani <vjasani@apache.org>
Reviewed-by: Hui Fei <ferhui@apache.org>

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataXceiver.java

@@ -1093,7 +1093,7 @@ class DataXceiver extends Receiver implements Runnable {
     if (!dataXceiverServer.balanceThrottler.acquire()) { // not able to start
       String msg = "Not able to copy block " + block.getBlockId() + " " +
           "to " + peer.getRemoteAddressString() + " because threads " +
-          "quota is exceeded.";
+          "quota=" + dataXceiverServer.balanceThrottler.getMaxConcurrentMovers() + " is exceeded.";
       LOG.info(msg);
       sendResponse(ERROR, msg);
       return;
@@ -1167,7 +1167,7 @@ class DataXceiver extends Receiver implements Runnable {
     if (!dataXceiverServer.balanceThrottler.acquire()) { // not able to start
       String msg = "Not able to receive block " + block.getBlockId() +
           " from " + peer.getRemoteAddressString() + " because threads " +
-          "quota is exceeded.";
+          "quota=" + dataXceiverServer.balanceThrottler.getMaxConcurrentMovers() + " is exceeded.";
       LOG.warn(msg);
       sendResponse(ERROR, msg);
       return;