linux-kernel - Re: device namespaces

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Message-ID: <b9ea9116-7120-b0a7-b739-dd8513e12c5e@suse.de>
Date:   Wed, 9 Jun 2021 09:02:36 +0200
From:   Hannes Reinecke <hare@...e.de>
To:     Christian Brauner <christian.brauner@...ntu.com>,
        "Eric W. Biederman" <ebiederm@...ssion.com>
Cc:     gregkh@...uxfoundation.org, containers@...ts.linux.dev,
        linux-kernel@...r.kernel.org, lkml@...ux.net
Subject: Re: device namespaces

On 6/9/21 8:38 AM, Christian Brauner wrote:
> On Tue, Jun 08, 2021 at 12:16:43PM -0500, Eric W. Biederman wrote:
>> Hannes Reinecke <hare@...e.de> writes:
>>
>>> On 6/8/21 4:29 PM, Christian Brauner wrote:
>>>> On Tue, Jun 08, 2021 at 04:10:08PM +0200, Hannes Reinecke wrote:
[ .. ]
>>> Granted, modifying sysfs layout is not something for the faint-hearted,
>>> and one really has to look closely to ensure you end up with a
>>> consistent layout afterwards.
>>>
>>> But let's see how things go; might well be that it turns out to be too
>>> complex to consider. Can't tell yet.
>>
>> I would suggest aiming for something like devptsfs without the
>> complication of /dev/ptmx.
>>
>> That is a pseudo filesystem that has a control node and virtual block
>> devices that were created using that control node.
> 
> Also see android/binder/binderfs.c
> 
Ah. Will have a look.

>>
>> That is the cleanest solution I know and is not strictly limited to use
>> with containers so it can also gain greater traction.  The interaction
>> with devtmpfs should be simply having devtmpfs create a mount point for
>> that filesystem.
>>
>> This could be a new cleaner api for things like loopback devices.
> 
> I sent a patchset that implemented this last year.
> 
Do you have a pointer/commit hash for this?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke                Kernel Storage Architect
hare@...e.de                              +49 911 74053 688
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