[Devel] Re: [PATCH] netns: Delete virtual interfaces during namespace cleanup

[Pavel Emelyanov]

Eric W. Biederman wrote:
> Pavel Emelyanov <xemul at openvz.org> writes:
> 
>> I remember that I promised to prepare the wait-extending patch. But I
>> haven't manage to find time for this, sorry :( In a month or two I will
>> finish one time-hungry task and hopefully be able to do it.
>>
>> As far as this particular patch is concerned.
>>
>> All the virtual devices we have now in namespaces (vlan and tunnels)
>> kill themselves *before* this code is called. But even if we try to
>> move this destruction from modules to here, we'll be in a tricky
>> situation, when the e.g. ipip module has already kfree-d the net_ipip
>> structure, while none of ipip devices are released yet.
>>
>> If we try to look in the future - if we ever have a virtual device
>> driver, that will be able to create its devices in namespace, we'll
>> have to destroy all these devices *before* (or inside) this driver's
>> net->exit callback is called, but this patch dies the ->dellink call
>> at the very end, i.e. *after* any potential ->exit callback.
>>
>> Eric - did you see any device, that was ->dellink-ed by this patch?
> 
> macvlan, veth, and dummy interfaces.  Basically
> everything I use this deletes the virtual interfaces, instead
> of sending them back to the initial network namespace.

OK, then.

Acked-by: Pavel Emelyanov <xemul at openvz.org>

>>From the looks of the code vlans are also be handled.
> 
> Things like tun/tap and ipip are handled in the exit methods and I
> have no problem with that, although I do wonder if we are handling
> moving or refusing to move them between namespaces properly.
> 
> For devices that don't need a dedicated virtual interface in
> every network namespace this certainly looks like the easiest
> way to handle them, as the driver doesn't need to a thing
> about network namespaces and the right thing just happens.
> 
> Eric
> 

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