HDFS-15518. Wrong operation name in FsNamesystem for listSnapshots. (#2217)

* HDFS-15518. Fixed String operationName = ListSnapshot.

* HDFS-15518. Changed ListSnapshot to operationName.

Co-authored-by: Aryan Gupta <aryan.gupta@cloudera.com>

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

@@ -7031,7 +7031,7 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
    */
   public SnapshotStatus[] getSnapshotListing(String snapshotRoot)
       throws IOException {
-    final String operationName = "listSnapshotDirectory";
+    final String operationName = "ListSnapshot";
     SnapshotStatus[] status;
     checkOperation(OperationCategory.READ);
     boolean success = false;
@@ -7048,10 +7048,10 @@ public class FSNamesystem implements Namesystem, FSNamesystemMBean,
         readUnlock(operationName, getLockReportInfoSupplier(null));
       }
     } catch (AccessControlException ace) {
-      logAuditEvent(success, "listSnapshots", snapshotRoot);
+      logAuditEvent(success, operationName, snapshotRoot);
       throw ace;
     }
-    logAuditEvent(success, "listSnapshots", snapshotRoot);
+    logAuditEvent(success, operationName, snapshotRoot);
     return status;
   }
   /**