code: void startFile(String src, PermissionStatus permissions,
                   String holder, String clientMachine,
                   boolean overwrite, boolean createParent, short replication, long blockSize
    ) throws IOException {
      INodeFileUnderConstruction file =
        startFileInternal(src, permissions, holder, clientMachine, overwrite, false,
        createParent, replication, blockSize);
      getEditLog().logSync(false);
      if (auditLog.isInfoEnabled()) {
        logAuditEvent(getCurrentUGI(),
          Server.getRemoteIp(),
          "create", src, null, file);
      }
    }
docs: Create a new file entry in the namespace.
  
  @throws IOException if file name is invalid
  {@link FSDirectory#isValidToCreate(String)}.
  @see ClientProtocol#create(String, FsPermission, String, boolean, short, long)