Re: [patch net-next] vlan: Don't allow vlan devices to change network namespaces.

[chenweilong <chenweilong@huawei.com>]

On 2014/4/23 15:23, Nicolas Dichtel wrote:
> Le 23/04/2014 04:40, chenweilong a écrit :
>> On 2014/4/22 22:26, Eric Dumazet wrote:
>>> On Tue, 2014-04-22 at 20:43 +0800, Chen Weilong wrote:
>>>> From: Weilong Chen <chenweilong@huawei.com>
>>>>
>>>> Like bonding, vlan as netdevice doesn't cross netns boundaries.
>>>>
>>>> Vlan port and vlan itself live in same netns.
>>>
>>> Please explain why you believe it should be like that.
>>>
>>> bonding and vlan have quite different purpose, so your changelog is
>>> quite obscure.
>>>
>>> We had a discussion like this one with macvlan, and prior patch was
>>> rejected.
>>>
>>>
>>>
>>>
>> This idea comes from the different result of two changing namespace orders.
>> Test on eth1 and its vlan eth1.5, move them form default ns to a new ns called net0.
>> 1.move eth1 first,and then eth1.5;
>> 2.move eth1.5 first, and then eth1;
>> As a network manager, I will be happy they both work, I don't care about the orders.
>> But, 1) doesn't work, if eth1 was moved to other ns, all related vlans were unregisted.
>> you need to create a new eth1.5 in net0.
>> And, 2) is not safe, if someone forgets to move eth1, eth1.5 will not work, making
>> things complex.
> We have to fix this case, because it is a valid use case to have eth1.5 in net0
> and eth1 in another ns.
> 
eth1.5 can receive and send packets in net0, the problem is you can't add a new eth1.5
in old ns, report 'error: File exists'.

>>
>> So what's the better order ?
>> I prefer 1), when a vlan dev is setup, it has a namespace, and belongs to it,
>> When somebody moves it, it should say 'hey boy, don't move me,I like here :0'
>>
>> Thanks,
>> Weilong
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