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From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Wed, 11 May 2022 11:40:59 +0200
Message-ID: <CAJfpegseGaWHkjdQj7XiR=TQNFpPZzDF_rTXces2oRz=x0N7OA@mail.gmail.com>
Subject: Re: [PATCH v4 0/3] FUSE: Implement atomic lookup + open/create
To:     Vivek Goyal <vgoyal@redhat.com>
Cc:     Bernd Schubert <bschubert@ddn.com>,
        Dharmendra Hans <dharamhans87@gmail.com>,
        linux-fsdevel@vger.kernel.org,
        fuse-devel <fuse-devel@lists.sourceforge.net>,
        linux-kernel@vger.kernel.org
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On Thu, 5 May 2022 at 21:59, Vivek Goyal <vgoyal@redhat.com> wrote:

> Oh, I have no issues with the intent. I will like to see cut in network
> traffic too (if we can do this without introducing problems). My primary
> interest is that this kind of change should benefit virtiofs as well.

One issue with that appears to be checking permissions.   AFAIU this
patchset only enables the optimization if default_permissions is
turned off (i.e. all permission checking is done by the server).  But
virtiofs uses the default_permissions model.

I'm not quite sure about this limitation, guessing that it's related
to the fact that the permissions may be stale at the time of checking?

Thanks,
Miklos