Re: [PATCH RESEND V12 3/8] fuse: Definitions and ioctl for passthrough

[Miklos Szeredi <miklos@szeredi.hu>]

On Fri, 12 May 2023 at 21:37, Amir Goldstein <amir73il@gmail.com> wrote:

> I was waiting for LSFMM to see if and how FUSE-BPF intends to
> address the highest value use case of read/write passthrough.
>
> From what I've seen, you are still taking a very broad approach of
> all-or-nothing which still has a lot of core design issues to address,
> while these old patches already address the most important use case
> of read/write passthrough of fd without any of the core issues
> (credentials, hidden fds).
>
> As far as I can tell, this old implementation is mostly independent of your
> lookup based approach - they share the low level read/write passthrough
> functions but not much more than that, so merging them should not be
> a blocker to your efforts in the longer run.
> Please correct me if I am wrong.
>
> As things stand, I intend to re-post these old patches with mandatory
> FOPEN_PASSTHROUGH_AUTOCLOSE to eliminate the open
> questions about managing mappings.
>
> Miklos, please stop me if I missed something and if you do not
> think that these two approaches are independent.

Do you mean that the BPF patches should use their own passthrough mechanism?

I think it would be better if we could agree on a common interface for
passthough (or per Paul's suggestion: backing) mechanism.

Let's see this patchset and then we can discuss how this could be
usable for the BPF case as well.

Thanks,
Miklos