Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20200925083507.13603-1-ptikhomirov@virtuozzo.com> <20200925083507.13603-3-ptikhomirov@virtuozzo.com>
In-Reply-To: <20200925083507.13603-3-ptikhomirov@virtuozzo.com>
From:   Miklos Szeredi <miklos@szeredi.hu>
Date:   Tue, 6 Oct 2020 17:13:25 +0200
Message-ID: <CAJfpegvgmnWrmsACuWe_hYCfVm2r0Ltv0C+sN+3T1DBMzrGE9w@mail.gmail.com>
Subject: Re: [PATCH v4 2/2] ovl: introduce new "uuid=off" option for inodes
 index feature
To:     Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
Cc:     Amir Goldstein <amir73il@gmail.com>,
        Vivek Goyal <vgoyal@redhat.com>,
        overlayfs <linux-unionfs@vger.kernel.org>,
        linux-kernel@vger.kernel.org
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Fri, Sep 25, 2020 at 10:35 AM Pavel Tikhomirov
<ptikhomirov@virtuozzo.com> wrote:

> Note: In our (Virtuozzo) use case users inside a container can create
> "regular" overlayfs mounts without any "index=" option, but we still
> want to migrate this containers with CRIU so we set "index=on" as kernel
> default so that all the container overlayfs mounts get support of file
> handles automatically. With "uuid=off" we want the same thing (to be
> able to "copy" container with uuid change) - we would set kernel default
> so that all the container overlayfs mounts get "uuid=off" automatically.

I'm not sure I buy that argument for a kernel option.   It should
rather be a "container" option in that case, but AFAIK the kernel
doesn't have a concept of a container.  I think this needs to be
discussed on the relevant mailing lists.

As of now mainline kernel doesn't support unprivileged overlay mounts,
so I guess this is not an issue.  Let's just merge this without the
kernel and the module options.

Thanks,
Miklos