HDFS-14218. EC: Ls -e throw NPE when directory ec policy is disabled. Contributed by Ayush Saxena.

(cherry picked from commit 7d6792e5d2)

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

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

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

@@ -1010,5 +1010,26 @@
       </comparators>
     </test>
 
+    <test>
+      <description>ls: file with disabled EC Policy</description>
+      <test-commands>
+        <command>-fs NAMENODE -mkdir -p /ecdir</command>
+        <ec-admin-command>-fs NAMENODE -setPolicy -path /ecdir -policy XOR-2-1-1024k</ec-admin-command>
+        <command>-fs NAMENODE -touchz /ecdir/file1</command>
+        <ec-admin-command>-fs NAMENODE -disablePolicy -policy XOR-2-1-1024k</ec-admin-command>
+        <command>-fs NAMENODE -ls -e /ecdir</command>
+      </test-commands>
+      <cleanup-commands>
+        <command>-fs NAMENODE -rmdir /ecdir</command>
+        <ec-admin-command>-fs NAMENODE -enablePolicy -policy XOR-2-1-1024k</ec-admin-command>
+      </cleanup-commands>
+      <comparators>
+        <comparator>
+          <type>RegexpComparator</type>
+          <expected-output>^-rw-r--r--( )*1( )*USERNAME( )*supergroup( )*[A-Za-z0-9-]{1,}( )*0( )*[0-9]{4,}-[0-9]{2,}-[0-9]{2,} [0-9]{2,}:[0-9]{2,}( )*/ecdir/file1</expected-output>
+        </comparator>
+      </comparators>
+    </test>
+
   </tests>
 </configuration>