Using direct IO with ecryptfs and similar stackable file systems

Does "ecryptfs" supp开发者_高级运维ort direct I/O? In general, how can a "stackable" file system, that modifies buffer provided by user support direct I/O?

ecryptfs does not support direct I/O.

There is no implementation of direct_IO() callback in ecryptfs address_space_operations.

I haven't looked into this much, but I would personally use a decorator pattern for the file system drivers, so that ecryptfs sits on top of any of the actual device drivers. Then when calls are made, they go into ecryptfs code, then ecryptfs calls the device drivers and does the writing.