[Devel] Re: [PATCH 0/3] lockd: use per-net refrence-counted NSM clients

[Chuck Lever]

On Sep 14, 2012, at 1:38 PM, Myklebust, Trond wrote:

> On Fri, 2012-09-14 at 13:01 -0400, Chuck Lever wrote:
>> What happens if statd is restarted?
> 
> Nothing unusual. Why?

The NSM upcall transport is a potential application for TCP + softconn, now that a persistent rpc_clnt is used.  It just depends on what failure mode we'd like to optimize for.

> 
>> Sent from my iPhone
>> 
>> On Sep 14, 2012, at 10:25 AM, Stanislav Kinsbursky <skinsbursky at parallels.com> wrote:
>> 
>>> This is a bug fix for https://bugzilla.redhat.com/show_bug.cgi?id=830862.
>>> 
>>> The problem is that with NFSv4 mount in container (with separated mount
>>> namesapce) and active lock on it, dying child reaped of this container will
>>> try to umount NFS and doing this will try to create RPC client to send
>>> unmonitor request to statd.
>>> But creation of RCP client requires valid current->nsproxy (for operation with
>>> utsname()) and during umount on child reaper exit it's equal to zero.
>>> 
>>> Proposed solution is to introduce refrence-counter per-net NSM client, which
>>> is created on fist monitor call and destroyed after the lst monitor call.
>>> 
>>> The following series implements...
>>> 
>>> ---
>>> 
>>> Stanislav Kinsbursky (3):
>>>     lockd: use rpc client's cl_nodename for id encoding
>>>     lockd: per-net NSM client creation and destruction helpers introduced
>>>     lockd: create and use per-net NSM RPC clients on MON/UNMON requests
>>> 
>>> 
>>> fs/lockd/mon.c   |   91 +++++++++++++++++++++++++++++++++++++++++++-----------
>>> fs/lockd/netns.h |    4 ++
>>> fs/lockd/svc.c   |    1 +
>>> 3 files changed, 77 insertions(+), 19 deletions(-)
>>> 
>>> 
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> 
> -- 
> Trond Myklebust
> Linux NFS client maintainer
> 
> NetApp
> Trond.Myklebust at netapp.com
> www.netapp.com

-- 
Chuck Lever
chuck[dot]lever[at]oracle[dot]com