Table is full even with innodb_file_per_table

I am trying to create an index to my table using alter query. My my.cnf file innodb_data_home_dir = /usr/local/mysql5/data innodb_data_file_path = ibdata1:60021538816;ibdata2:300M;ibdata3:30000M;ibdata4:10000M;ibdata5:10000M:autoextend innodb_buffer_pool_instances = 3 innodb_buffer_pool_size = 3G innodb_additional_mem_pool_size = 8M # Set .._log_file_size to 25 % of buffer pool size innodb_log_file_size = 256M innodb_additional_mem_pool_size = 128M innodb_log_buffer_size = 8M innodb_flush_log_at_trx_commit = 2 innodb_lock_wait_timeout = 100 innodb_file_per_table innodb_flush_method=O_DIRECT Still every time my alter query alter table user add unique index idx_emailHash (emailHash); giving Table 'user' is full? What am I missing. I am using MySQL 5.6 Some more info [root@db data]# ll | grep user -rw-rw----. 1 mysql mysql 19551 Jun 10 14:33 user.frm -rw-rw----. 1 mysql mysql 28412215296 Jun 10 22:58 user.ibd [root@db data]# ll | grep ibd -rwxr-xr-x. 1 mysql mysql 60021538816 Jun 10 22:58 ibdata1 -rw-rw----. 1 mysql mysql 314572800 Jun 10 22:20 ibdata2 -rw-rw----. 1 mysql mysql 31457280000 Jun 10 22:33 ibdata3 -rw-rw----. 1 mysql mysql 10485760000 Jun 10 22:51 ibdata4 -rw-rw----. 1 mysql mysql 10485760000 Jun 10 22:51 ibdata5