There are two separate issues here: 1) innodb_flush_method=O_DIRECT should not make bitmap files O_DIRECT; 2) innodb_flush_method=ALL_O_DIRECT should work with bitmap files.
There are two separate issues here: flush_method= O_DIRECT should not make bitmap files O_DIRECT; flush_method= ALL_O_DIRECT should work with bitmap files.
1) innodb_
2) innodb_