HADOOP-13280. FileSystemStorageStatistics#getLong(“readOps“) should return readOps + largeReadOps (Mingliang Liu via cmccabe)

(cherry picked from commit 5370a6ffae)
(cherry picked from commit 7db1e57cc1)

Conflicts:
    hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemStorageStatistics.java

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/fs/FileSystemStorageStatistics.java

@@ -83,7 +83,7 @@ public class FileSystemStorageStatistics extends StorageStatistics {
     case "bytesWritten":
       return data.getBytesWritten();
     case "readOps":
-      return Long.valueOf(data.getReadOps());
+      return (long) (data.getReadOps() + data.getLargeReadOps());
     case "largeReadOps":
       return Long.valueOf(data.getLargeReadOps());
     case "writeOps":

hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/fs/TestFileSystemStorageStatistics.java

@@ -0,0 +1,118 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ * <p>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <p>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.hadoop.fs;
+
+import org.apache.commons.lang.math.RandomUtils;
+import org.apache.hadoop.fs.StorageStatistics.LongStatistic;
+
+import org.junit.Before;
+import org.junit.Rule;
+import org.junit.Test;
+
+import org.junit.rules.ExpectedException;
+import org.junit.rules.Timeout;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Iterator;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+
+/**
+ * This tests basic operations of {@link FileSystemStorageStatistics} class.
+ */
+public class TestFileSystemStorageStatistics {
+  private static final Logger LOG = LoggerFactory.getLogger(
+      TestFileSystemStorageStatistics.class);
+  private static final String FS_STORAGE_STATISTICS_NAME = "test-fs-statistics";
+  private static final String[] STATISTICS_KEYS = {
+      "bytesRead",
+      "bytesWritten",
+      "readOps",
+      "largeReadOps",
+      "writeOps"
+  };
+
+  private FileSystem.Statistics statistics =
+      new FileSystem.Statistics("test-scheme");
+  private FileSystemStorageStatistics storageStatistics =
+      new FileSystemStorageStatistics(FS_STORAGE_STATISTICS_NAME, statistics);
+
+  @Rule
+  public final Timeout globalTimeout = new Timeout(10 * 1000);
+  @Rule
+  public final ExpectedException exception = ExpectedException.none();
+
+  @Before
+  public void setup() {
+    statistics.incrementBytesRead(RandomUtils.nextInt(100));
+    statistics.incrementBytesWritten(RandomUtils.nextInt(100));
+    statistics.incrementLargeReadOps(RandomUtils.nextInt(100));
+    statistics.incrementWriteOps(RandomUtils.nextInt(100));
+  }
+
+  @Test
+  public void testgetLongStatistics() {
+    Iterator<LongStatistic> iter = storageStatistics.getLongStatistics();
+    while (iter.hasNext()) {
+      final LongStatistic longStat = iter.next();
+      assertNotNull(longStat);
+      final long expectedStat = getStatisticsValue(longStat.getName());
+      LOG.info("{}: FileSystem.Statistics={}, FileSystemStorageStatistics={}",
+          longStat.getName(), expectedStat, longStat.getValue());
+      assertEquals(expectedStat, longStat.getValue());
+    }
+  }
+
+  @Test
+  public void testGetLong() {
+    for (String key : STATISTICS_KEYS) {
+      final long expectedStat = getStatisticsValue(key);
+      final long storageStat = storageStatistics.getLong(key);
+      LOG.info("{}: FileSystem.Statistics={}, FileSystemStorageStatistics={}",
+          key, expectedStat, storageStat);
+      assertEquals(expectedStat, storageStat);
+    }
+  }
+
+  /**
+   * Helper method to retrieve the specific FileSystem.Statistics value by name.
+   *
+   * Basically, the {@link FileSystemStorageStatistics} should do this
+   * internally in a similar approach.
+   */
+  private long getStatisticsValue(String name) {
+    switch (name) {
+    case "bytesRead":
+      return statistics.getBytesRead();
+    case "bytesWritten":
+      return statistics.getBytesWritten();
+    case "readOps":
+      return statistics.getReadOps();
+    case "largeReadOps":
+      return statistics.getLargeReadOps();
+    case "writeOps":
+      return statistics.getWriteOps();
+    default:
+      return 0;
+    }
+  }
+
+}