Manually modify master-bin.index I have an issue with MariaDB Server 5.5.56 replication. The slave got stuck and when I realized that we had already lost some of the bins. So this is the scenario :

In master :

MariaDB [(none)]> show binary logs;
+-------------------+------------+
| Log_name          | File_size  |
+-------------------+------------+
| master-bin.000320 | 1073742333 |
| master-bin.000321 | 1074247558 |
| master-bin.000322 |  753717941 |
| master-bin.000323 |  883803465 |
+-------------------+------------+
4 rows in set (0.01 sec)  

cat master-bin.index
./master-bin.000320
./master-bin.000321
./master-bin.000322
./master-bin.000323  

In slave ( excerpt )

MariaDB [(none)]> SHOW SLAVE STATUS\G
*************************** 1. row ***************************
               Slave_IO_State:
              Master_Log_File: master-bin.000312
          Read_Master_Log_Pos: 405852801
               Relay_Log_File: mariadb-relay-bin.000942
                Relay_Log_Pos: 405852988
        Relay_Master_Log_File: master-bin.000312
             Slave_IO_Running: No
            Slave_SQL_Running: Yes
          Exec_Master_Log_Pos: 405852703
              Relay_Log_Space: 405853426
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 1236
                Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'Could not find first log file name in binary log index file'
               Last_SQL_Errno: 0
               Last_SQL_Error:
  Replicate_Ignore_Server_Ids:
             Master_Server_Id: 1
1 row in set (0.00 sec)  

So my idea to try and recover the slave is :

1.- In master : stop mariadb service
2.- In master : copy from backup bins 312 to 319
3.- In master : manually add bins 312 to 319 to master-bin.index
4.- In master : start mariadb service
5.- In slave : start slave  

Would that work ? Is there any other way to solve my problem ? I know manually modifying master-bin.index is not recommended but I can not think of any other alternative to avoid recreating the slave.

Thanks in advance.
The best advice would be to rebuild the slave. Missing 8 binary logs means you may be missing a lot of transactions. Another option would be to execute CHANGE MASTER to and move to the next available binary log. You may need to skip slave errors along the way until the slave 'catches up' BUT you have to use pt-table-checksum and pt-table-sync to "resync" the data between these nodes.