On Thu, Jun 15, 2017 at 12:11:58PM +0100, Al Viro wrote:

Which flags are you talking about?  aio ones?  AFAICS, it's the same
kind of thing as "can we lseek?" or "can we read/pread?", etc.
What would that field look like?  Note that some of those might depend
upon the flags passed to open(), so shoving them into file_operations
might mean splitting file_operations instances...  Details, please.

Yeah, I'll take my suggestion back.