Re: [PATCH v2] locks: Filter /proc/locks output on proc pid ns

From: "J. Bruce Fields" <bfields@fieldses.org>
To: Nikolay Borisov <kernel@kyup.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>,
	Jeff Layton <jlayton@poochiereds.net>,
	Andrey Vagin <avagin@openvz.org>,
	containers@lists.linux-foundation.org,
	linux-kernel@vger.kernel.org, ebiederm@xmission.com,
	linux-fsdevel@vger.kernel.org, viro@zeniv.linux.org.uk
Subject: Re: [PATCH v2] locks: Filter /proc/locks output on proc pid ns
Date: Wed, 3 Aug 2016 11:06:31 -0400	[thread overview]
Message-ID: <20160803150631.GA3789@fieldses.org> (raw)
In-Reply-To: <57A20702.3040805@kyup.com>

On Wed, Aug 03, 2016 at 06:00:18PM +0300, Nikolay Borisov wrote:
> 
> 
> On 08/03/2016 05:54 PM, Pavel Emelyanov wrote:
> > On 08/03/2016 05:17 PM, Nikolay Borisov wrote:
> >>
> >>
> [SNIP]
> >>
> >> [CCing some people from openvz/CRIU]
> > 
> > Thanks :)
> > 
> >> My train of thought was "we should have means which would be the one
> >> universal truth about everything and this would be a process in the
> >> init_pid_ns". I don't have strong preference as long as I'm not breaking
> >> userspace. As I said before - I think the CRIU guys might be using that
> >> interface.
> > 
> > This particular change won't break us mostly because we've switched to
> > reading the /proc/pid/fdinfo/n files for locks.
> 
> [thinking out loud here]
> 
> I've never actually looked into those files but now that I have it seems
> to make sense to also switch 'lsof' to actually reading the locks from
> the available pids directories rather than relying on the global
> /proc/locks interface. Oh well :)

Digging around...  Oh, I see, there's an optional 'lock:..' line in
/proc/[pid]/fdinfo/[pid] file, is that what you're looking at?  I'd
forgotten.  Yeah, maybe that would make more sense long term.

--b.

> 
> [/thinking out loud here]
> 
> > 
> > -- Pavel
> > 
> >>>
> >>>>>> +	    && (proc_pidns != ns_of_pid(fl->fl_nspid)))
> >>>>> +		return 0;
> >>>> +
> >>>>>  	lock_get_status(f, fl, iter->li_pos, "");
> >>>>  
> >>>>>  	list_for_each_entry(bfl, &fl->fl_block, fl_block)
> >>>
> >> .
> >>
> > 
> > _______________________________________________
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> > https://lists.linuxfoundation.org/mailman/listinfo/containers
> > 