Revert "HDFS-15884. RBF: Remove unused method getCreateLocation in RouterRpcServer (#2754). Contributed by tomscut."

This reverts commit e565b05c80c731898a54f8c1d358c12090ca5bbf.

The removed method needs to be used in HDFS-15423.

hadoop-hdfs-project/hadoop-hdfs-rbf/src/main/java/org/apache/hadoop/hdfs/server/federation/router/RouterRpcServer.java

@@ -776,6 +776,20 @@ public class RouterRpcServer extends AbstractService implements ClientProtocol,
         replication, blockSize, supportedVersions, ecPolicyName, storagePolicy);
   }
 
+
+  /**
+   * Get the location to create a file. It checks if the file already existed
+   * in one of the locations.
+   *
+   * @param src Path of the file to check.
+   * @return The remote location for this file.
+   * @throws IOException If the file has no creation location.
+   */
+  RemoteLocation getCreateLocation(final String src) throws IOException {
+    final List<RemoteLocation> locations = getLocationsForPath(src, true);
+    return getCreateLocation(src, locations);
+  }
+
   /**
    * Get the location to create a file. It checks if the file already existed
    * in one of the locations.