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From: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: Amir Goldstein <amir73il@gmail.com>,
	Vivek Goyal <vgoyal@redhat.com>,
	overlayfs <linux-unionfs@vger.kernel.org>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v4 2/2] ovl: introduce new "uuid=off" option for inodes index feature
Date: Tue, 13 Oct 2020 16:54:38 +0300	[thread overview]
Message-ID: <abac619b-dec4-8179-cb59-52c8f14422a1@virtuozzo.com> (raw)
In-Reply-To: <CAJfpegvgmnWrmsACuWe_hYCfVm2r0Ltv0C+sN+3T1DBMzrGE9w@mail.gmail.com>



On 10/6/20 6:13 PM, Miklos Szeredi wrote:
> 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.

Virtuozzo kernel does have a "container" concept and we do have 
unprivileged overlay mounts to support docker inside Virtuozzo 
containers. We don't face any major issues with it. But you are right 
it's not mainstream.

Probably a normal user of mainstream kernel also might want to set 
index=on+uuid=off by default, so that all their docker containters 
automatically support inotifies and survive backing disk uuid change 
automaticaly.

I will prepare next patchset version without default.

> 
> Thanks,
> Miklos
> 

-- 
Best regards, Tikhomirov Pavel
Software Developer, Virtuozzo.

      reply	other threads:[~2020-10-13 13:54 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-25  8:35 [PATCH v4 0/2] ovl introduce "uuid=off" Pavel Tikhomirov
2020-09-25  8:35 ` [PATCH v4 1/2] ovl: propagate ovl_fs to ovl_decode_real_fh and ovl_encode_real_fh Pavel Tikhomirov
2020-09-25 16:37   ` Amir Goldstein
2020-09-25  8:35 ` [PATCH v4 2/2] ovl: introduce new "uuid=off" option for inodes index feature Pavel Tikhomirov
2020-09-25 16:42   ` Amir Goldstein
2020-09-28  7:22     ` Pavel Tikhomirov
2020-10-06 15:13   ` Miklos Szeredi
2020-10-13 13:54     ` Pavel Tikhomirov [this message]

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