HDFS-12371. BlockVerificationFailures and BlocksVerified show up as 0 in Datanode JMX. Contributed by Hanisha Koneru.

(cherry picked from commit 6bf921a5c3152a307b5c0903056d73ce07775a08)

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

@@ -37,6 +37,7 @@ import org.apache.hadoop.hdfs.server.datanode.BlockScanner.Conf;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeReference;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi.BlockIterator;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.FsVolumeSpi;
+import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.hdfs.util.DataTransferThrottler;
 import org.apache.hadoop.io.IOUtils;
 import org.apache.hadoop.util.Time;
@@ -81,6 +82,8 @@ public class VolumeScanner extends Thread {
    */
   private final DataNode datanode;
 
+  private final DataNodeMetrics metrics;
+
   /**
    * A reference to the volume that we're scanning.
    */
@@ -300,6 +303,7 @@ public class VolumeScanner extends Thread {
   VolumeScanner(Conf conf, DataNode datanode, FsVolumeReference ref) {
     this.conf = conf;
     this.datanode = datanode;
+    this.metrics = datanode.getMetrics();
     this.ref = ref;
     this.volume = ref.getVolume();
     ScanResultHandler handler;
@@ -444,12 +448,14 @@ public class VolumeScanner extends Thread {
       throttler.setBandwidth(bytesPerSec);
       long bytesRead = blockSender.sendBlock(nullStream, null, throttler);
       resultHandler.handle(block, null);
+      metrics.incrBlocksVerified();
       return bytesRead;
     } catch (IOException e) {
       resultHandler.handle(block, e);
     } finally {
       IOUtils.cleanup(null, blockSender);
     }
+    metrics.incrBlockVerificationFailures();
     return -1;
   }