HDFS-9208. Disabling atime may fail clients like distCp. (Kihwal Lee via yliu)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -2081,6 +2081,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-9237. NPE at TestDataNodeVolumeFailureToleration#tearDown.
     (Brahma Reddy Battula via ozawa)
 
+    HDFS-9208. Disabling atime may fail clients like distCp. (Kihwal Lee via
+    yliu)
+
 Release 2.7.2 - UNRELEASED
 
   INCOMPATIBLE CHANGES

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirAttrOp.java

@@ -42,7 +42,6 @@
 import java.util.EnumSet;
 import java.util.List;
 
-import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_NAMENODE_ACCESSTIME_PRECISION_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_QUOTA_BY_STORAGETYPE_ENABLED_KEY;
 import static org.apache.hadoop.hdfs.DFSConfigKeys.DFS_STORAGE_POLICY_ENABLED_KEY;
 
@@ -97,13 +96,6 @@ static HdfsFileStatus setOwner(
   static HdfsFileStatus setTimes(
       FSDirectory fsd, String src, long mtime, long atime)
       throws IOException {
-    if (!fsd.isAccessTimeSupported() && atime != -1) {
-      throw new IOException(
-          "Access time for hdfs is not configured. " +
-              " Please set " + DFS_NAMENODE_ACCESSTIME_PRECISION_KEY
-              + " configuration parameter.");
-    }
-
     FSPermissionChecker pc = fsd.getPermissionChecker();
     byte[][] pathComponents = FSDirectory.getPathComponentsForReservedPath(src);
 

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

@@ -40,6 +40,7 @@
 import org.apache.hadoop.hdfs.server.namenode.NameNodeAdapter;
 import org.apache.hadoop.test.MockitoUtil;
 import org.apache.hadoop.util.Time;
+import org.junit.Assert;
 import org.junit.Test;
 import org.mockito.Mockito;
 
@@ -309,6 +310,36 @@ public void testGetBlockLocationsOnlyUsesReadLock() throws IOException {
     }
   }
 
+  /**
+   * Test whether atime can be set explicitly even when the atime support is
+   * disabled.
+   */
+  @Test
+  public void testAtimeUpdate() throws Exception {
+    Configuration conf = new HdfsConfiguration();
+    conf.setInt(DFSConfigKeys.DFS_NAMENODE_ACCESSTIME_PRECISION_KEY, 0);
+    MiniDFSCluster cluster = null;
+    FileSystem fs = null;
+
+    try {
+      cluster = new MiniDFSCluster.Builder(conf)
+          .numDataNodes(0)
+          .build();
+      fs = cluster.getFileSystem();
+
+      // Create an empty file
+      Path p = new Path("/testAtimeUpdate");
+      DFSTestUtil.createFile(cluster.getFileSystem(), p, 0, (short)1, 0L);
+
+      fs.setTimes(p, -1L, 123456L);
+      Assert.assertEquals(123456L, fs.getFileStatus(p).getAccessTime());
+    } finally {
+      if (cluster != null) {
+        cluster.shutdown();
+      }
+    }
+  }
+
   public static void main(String[] args) throws Exception {
     new TestSetTimes().testTimes();
   }