linux-kernel - Re: Re: [PATCH v4 3/3] fuse: add an implementation of open+getattr

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aWju_kqgdiOZt8gn@fedora.fritz.box>
Date: Thu, 15 Jan 2026 14:46:27 +0100
From: Horst Birthelmer <horst@...thelmer.de>
To: Bernd Schubert <bernd@...ernd.com>
Cc: Joanne Koong <joannelkoong@...il.com>, 
	Horst Birthelmer <horst@...thelmer.com>, Miklos Szeredi <miklos@...redi.hu>, linux-kernel@...r.kernel.org, 
	linux-fsdevel@...r.kernel.org, Horst Birthelmer <hbirthelmer@....com>, 
	Luis Henriques <luis@...lia.com>
Subject: Re: Re: [PATCH v4 3/3] fuse: add an implementation of open+getattr

On Thu, Jan 15, 2026 at 02:41:49PM +0100, Bernd Schubert wrote:
> 
> 
> On 1/15/26 14:38, Horst Birthelmer wrote:
> > On Wed, Jan 14, 2026 at 06:29:26PM -0800, Joanne Koong wrote:
> >> On Fri, Jan 9, 2026 at 10:27 AM Horst Birthelmer <horst@...thelmer.com> wrote:
> >>>
> >>> +
> >>> +       err = fuse_compound_send(compound);
> >>> +       if (err)
> >>> +               goto out;
> >>> +
> >>> +       err = fuse_compound_get_error(compound, 0);
> >>> +       if (err)
> >>> +               goto out;
> >>> +
> >>> +       err = fuse_compound_get_error(compound, 1);
> >>> +       if (err)
> >>> +               goto out;
> >>
> >> Hmm, if the open succeeds but the getattr fails, why not process it
> >> kernel-side as a success for the open? Especially since on the server
> >> side, libfuse will disassemble the compound request into separate
> >> ones, so the server has no idea the open is even part of a compound.
> >>
> >> I haven't looked at the rest of the patch yet but this caught my
> >> attention when i was looking at how fuse_compound_get_error() gets
> >> used.
> >>
> > After looking at this again ...
> > Do you think it would make sense to add an example of lookup+create, or would that just convolute things?
> 
> 
> I think that will be needed with the LOOKUP_HANDLE from Luis, if we go
> the way Miklos proposes. To keep things simple, maybe not right now?

I was thinking more along the lines of ... we would have more than one example especially for the error handling. Otherwise it is easy to miss something because the given example just doesn't need that special case.
Like the case above. There we would be perfectly fine with a function returning the first error, which in the case of lookup+create is the opposite of success and you would need to access every single error to check what actually happened.

> 
> 
> Thanks,
> Bernd