Re: Re: [RFC PATCH] fuse: support cache revalidation in writeback_cache mode

[Miklos Szeredi]

On Mon, 25 Apr 2022 at 15:33, Jiachen Zhang
<zhangjiachen.jaycee@xxxxxxxxxxxxx> wrote:
>
> On Mon, Apr 25, 2022 at 8:41 PM Miklos Szeredi <miklos@xxxxxxxxxx> wrote:
> >
> > On Fri, 25 Mar 2022 at 14:23, Jiachen Zhang
> > <zhangjiachen.jaycee@xxxxxxxxxxxxx> wrote:
> > >
> > > Hi all,
> > >
> > > This RFC patch implements attr cache and data cache revalidation for
> > > fuse writeback_cache mode in kernel. Looking forward to any suggestions
> > > or comments on this feature.
> >
> > Quick question before going into the details:  could the cache
> > revalidation be done in the userspace filesystem instead, which would
> > set/clear FOPEN_KEEP_CACHE based on the result of the revalidation?
> >
> > Thanks,
> > Miklos
>
> Hi, Miklos,
>
> Thanks for replying. Yes, I believe we can also perform the
> revalidation in userspace, and we can invalidate the data cache with
> FOPEN_KEEP_CACHE cleared. But for now, there is no way we can
> invalidate attr cache (c/mtime and size)  in writeback mode.

Can you please describe the use case for invalidating the attr cache?

Thanks,
Miklos