Re: [PATCH RFC 2/2] io_uring: add support for getdents

[Dave Chinner <david@fromorbit.com>]

On Fri, Apr 28, 2023 at 08:27:53PM +0900, Dominique Martinet wrote:
> Dominique Martinet wrote on Fri, Apr 28, 2023 at 03:14:52PM +0900:
> > > We already pass a struct dir_context to ->iterate_shared(), so we
> > > have a simple way to add context specific flags down the filesystem
> > > from iterate_dir(). This is similar to the iocb for file data IO
> > > that contains the flags field that holds the IOCB_NOWAIT context for
> > > io_uring based IO. So the infrastructure to plumb it all the way
> > > down the fs implementation of ->iterate_shared is already there.
> > 
> > Sure, that sounds like a good approach that isn't breaking the API (not
> > breaking iterate/iterate_shared implementations that don't look at the
> > flags and allowing the fs that want to look at it to do so)
> 
> Hmm actually I said that, but io_getdents() needs to know if the flag
> will be honored or not (if it will be honored, we can call this when
> issue_flags & IO_URING_F_NONBLOCK but if we're not sure the fs handles
> it then we risk blocking)

See the new FMODE_DIO_PARALLEL_WRITE flag for triggering filesystem
specific non-blocking io_uring behaviour....

-Dave.
-- 
Dave Chinner
david@fromorbit.com