HDFS-14274. EC: NPE While Listing EC Policy For A Directory Following Replication Policy. Contributed by Ayush Saxena.

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

@@ -188,7 +188,7 @@ public String getErasureCodingPolicyName(INode inode) {
           String ecPolicyName = WritableUtils.readString(din);
           return dir.getFSNamesystem()
               .getErasureCodingPolicyManager()
-              .getByName(ecPolicyName)
+              .getErasureCodingPolicyByName(ecPolicyName)
               .getName();
         }
       } else if (inode.getParent() != null) {

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

@@ -255,6 +255,22 @@ public ErasureCodingPolicy getByName(String name) {
     return ecpi.getPolicy();
   }
 
+  /**
+   * Get a {@link ErasureCodingPolicy} by policy name, including system
+   * policy, user defined policy and Replication policy.
+   * @return ecPolicy, or null if not found
+   */
+  public ErasureCodingPolicy getErasureCodingPolicyByName(String name) {
+    final ErasureCodingPolicyInfo ecpi = getPolicyInfoByName(name);
+    if (ecpi == null) {
+      if (name.equalsIgnoreCase(ErasureCodeConstants.REPLICATION_POLICY_NAME)) {
+        return SystemErasureCodingPolicies.getReplicationPolicy();
+      }
+      return null;
+    }
+    return ecpi.getPolicy();
+  }
+
   /**
    * Get a {@link ErasureCodingPolicyInfo} by policy name, including system
    * policy and user defined policy.

hadoop-hdfs-project/hadoop-hdfs/src/test/resources/testErasureCodingConf.xml

@@ -1055,5 +1055,24 @@
       </comparators>
     </test>
 
+    <test>
+      <description>ls: file with replication Policy</description>
+      <test-commands>
+        <command>-fs NAMENODE -mkdir -p /ecdir</command>
+        <ec-admin-command>-fs NAMENODE -setPolicy -path /ecdir -replicate</ec-admin-command>
+        <command>-fs NAMENODE -touchz /ecdir/file1</command>
+        <command>-fs NAMENODE -ls -e /</command>
+      </test-commands>
+      <cleanup-commands>
+        <command>-fs NAMENODE -rmdir /ecdir</command>
+      </cleanup-commands>
+      <comparators>
+        <comparator>
+          <type>RegexpComparator</type>
+          <expected-output>^drwxr-xr-x( )*-( )*USERNAME( )*supergroup( )*[A-Za-z0-9-]{1,}( )*0( )*[0-9]{4,}-[0-9]{2,}-[0-9]{2,} [0-9]{2,}:[0-9]{2,}( )*/ecdir</expected-output>
+        </comparator>
+      </comparators>
+    </test>
+
   </tests>
 </configuration>