ORA-01110 ORA-01111: name for data file 69 is unknown - rename to correct file

Today,  I has added a datafile of an tablespace with 'alter tablespace tbs_name add datafile '+DATA' 8g'.  I received a critical warning that the data guard standby machine done which could not synchronous the data after a period time.

I viewed the alert log and found that the DG machine's asm disk group has a little space which less then 8g, and can not synchronous the 'create datafile ...'.

So, I added the space of the asm disk group. When I startup the DG instance,  encountered the error 

MRP0: Background Media Recovery terminated with error 1111
Errors in file /u01/app/oracle/diag/rdbms/db4dg/cedb/trace/cedb_pr00_25766.trc:
ORA-01111: name for data file 69 is unknown - rename to correct file
ORA-01110: data file 69: '/u01/app/oracle/product/11.2.0/db_1/dbs/UNNAMED00069'
ORA-01157: cannot identify/lock data file 69 - see DBWR trace file
ORA-01111: name for data file 69 is unknown - rename to correct file
ORA-01110: data file 69: '/u01/app/oracle/product/11.2.0/db_1/dbs/UNNAMED00069'
Managed Standby Recovery not using Real Time Apply
Slave exiting with ORA-1111 exception

In order to deal with the erro , I done as the following:

alter system set standby_file_management=manual;
alter database create datafile 
  '/u01/app/oracle/product/11.2.0/db_1/dbs/UNNAMED00069' as '+DATA/db4dg/datafile/tbs_name';
  alter system set standby_file_management=auto;
alter database recover managed standby database disconnect from session using current logfile;  (11g)
alter database recover managed standby database disconnect from session;(10g)