From mboxrd@z Thu Jan  1 00:00:00 1970
From: Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org>
Subject: Re: [RFC][PATCH 0/8][v2]: Enable multiple mounts of devpts
Date: Wed, 03 Sep 2008 14:04:01 +0200
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To: "Eric W. Biederman" <ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org>
Cc: kyle-hoO6YkzgTuCM0SS3m2neIg@public.gmane.org, Dave Hansen <dave-gkUM19QKKo4@public.gmane.org>, bastian-yyjItF7Rl6lg9hUCZPvPmw@public.gmane.org, "H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>, containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, alan-qBU/x9rampVanCEyBjwyrvXRex20P6io@public.gmane.org, xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org
List-Id: containers.vger.kernel.org

Eric W. Biederman wrote:
> Cedric Le Goater <clg-NmTC/0ZBporQT0dZR+AlfA@public.gmane.org> writes:
>> Hello Eric,
>>
>> I've spent some time on the code and I'm facing some issues with the nsproxy 
>> API if we are to keep the mqueue namespace in nsproxy: 
>>
>> 	int copy_namespaces(unsigned long flags, struct task_struct *tsk);
>> 	void exit_task_namespaces(struct task_struct *tsk);
>> 	void switch_task_namespaces(struct task_struct *tsk, struct nsproxy
>> *new);
>> 	void free_nsproxy(struct nsproxy *ns);
>> 	int unshare_nsproxy_namespaces(unsigned long, struct nsproxy **,
>> 		struct fs_struct *);
>>
>> nsproxy designed to work closely with the clone flags and it is not well
>> suited to be called elsewhere than clone/unshare.
> 
> Right.
> 
>> So I could either : 
>>
>> (1) make a special case for the mqueue namespace and duplicate some code 
>>     to unshare it from ->get_sb() when the option 'newinstance' is used.
> 
> This is probably the best option. 
> 
> You should be able to just wrap create_new_namespaces(flags=0,...)
> to create a new one.
> 
> And then actually perform the unshare.
> 
> Which means in practice you will bump the ref count on
> mq_ns and then drop it and insert a new mq_ns pointer but overall
> that shouldn't be too bad.

Thanks for the comments, Eric. I should have something ready soon.

I'm currently reviewing the C/R patches that have been sent recently.

C.