Re: [PATCH 4/5] [RFC] fuse: Set and use IOCB_DIRECT when FOPEN_DIRECT_IO is set

[Miklos Szeredi <miklos@szeredi.hu>]

On Mon, 28 Aug 2023 at 16:48, Bernd Schubert <bernd.schubert@fastmail.fm> wrote:
>
> On 8/28/23 13:59, Miklos Szeredi wrote:
> > On Thu, 24 Aug 2023 at 17:07, Bernd Schubert <bschubert@ddn.com> wrote:

> >> -               if (!is_sync_kiocb(iocb) && iocb->ki_flags & IOCB_DIRECT) {
> >> -                       res = fuse_direct_IO(iocb, from);
> >> -               } else {
> >> -                       res = fuse_direct_io(&io, from, &iocb->ki_pos,
> >> -                                            FUSE_DIO_WRITE);
> >> -                       fuse_write_update_attr(inode, iocb->ki_pos, res);
> >
> > While I think this is correct, I'd really like if the code to be
> > replaced and the replacement are at least somewhat comparable.
>
> Sorry, I have a hard to time to understand "I'd really like if the code
> to be replaced".

What I meant is that generic_file_direct_write() is not an obvious
replacement for the  above lines of code.

The reason is that fuse_direct_IO() is handling the sync and async
cases in one function, while the above splits handling it based on
IOCB_DIRECT (which is now lost) and is_sync_kiocb(iocb).  If it's okay
to lose IOCB_DIRECT then what's the explanation for the above
condition?  It could be historic garbage, but we still need to
understand what is exactly happening.

Thanks,
Miklos