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From:   "Benjamin Coddington" <bcodding@redhat.com>
To:     "Trond Myklebust" <trondmy@hammerspace.com>
Cc:     chuck.lever@oracle.com, linux-nfs@vger.kernel.org
Subject: Re: v4 clientid uniquifiers in containers/namespaces
Date:   Tue, 08 Feb 2022 12:45:23 -0500
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On 8 Feb 2022, at 11:47, Trond Myklebust wrote:

> On Tue, 2022-02-08 at 06:32 -0500, Benjamin Coddington wrote:
>>
>> There's a bit of a chicken and egg problem with 2, though.  If the
>> nfs
>> module is loaded, the kernel notification gets sent as soon as you
>> create
>> the namespace.  Its not going to wait for you to move or exec udev
>> into
>> that
>> network namespace, and the notification is lost.
>
>
> Wait a minute... I missed this comment earlier, but it definitely
> points to a misunderstanding.
>
> The notification is _not_ sent by the act of loading a module. It is
> sent by the call to kobject_uevent() in nfs_netns_sysfs_setup(). That
> again is called as part of nfs_net_init() when the net namespace gets
> created.

My communication was poor.  The first notification is sent to udev when the
nfs module is loaded.  That is the initial creation of the sysfs, the
notification in the init namespace.

After that, if a network namespace is created and "the nfs module is
[already] loaded", the notification is immediately sent.

I think we're both understanding it and our understanding matches how it
works.

Ben