Re: [PATCH 04/28] fuse: adapt FUSE_DEV_IOC_BACKING_{OPEN,CLOSE} to add new iomap devices

Miklos Szeredi
2025-09-23T07:10:35Z

On Fri, 19 Sept 2025 at 19:42, Darrick J. Wong <djwong@kernel.org> wrote:
> I think capping at 1024 now (or 256, or even 8) is fine for now, and we
> can figure out the request protocol later when someone wants more.

Yeah, whichever.

> Alternately, I wonder if there's a way to pin the fd that is used to
> create the backing id so that the fuse server can't close it? There's
> probably no non-awful way to pin the fd table entry though.

I don't think this could work.

My idea back then was to create a kernel thread for each fuse instance
and have FUSE_DEV_IOC_BACKING_OPEN/_CLOSE operate on the file table of
this thread. Not sure how practical this would be.

Thanks,
Miklos

>
> --D
>
> > Thanks,
> > Amir.