linux-kernel - Re: [PATCH 1/3] lockd: use rpc client's cl

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Date:	Mon, 17 Sep 2012 14:48:05 +0400
From:	Stanislav Kinsbursky <skinsbursky@...allels.com>
To:	Chuck Lever <chuck.lever@...cle.com>
CC:	"Trond.Myklebust@...app.com" <Trond.Myklebust@...app.com>,
	"bfields@...ldses.org" <bfields@...ldses.org>,
	"linux-nfs@...r.kernel.org" <linux-nfs@...r.kernel.org>,
	"devel@...nvz.org" <devel@...nvz.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"jlayton@...hat.com" <jlayton@...hat.com>
Subject: Re: [PATCH 1/3] lockd: use rpc client's cl_nodename for id encoding

14.09.2012 23:08, Chuck Lever пишет:
> Hi-
>
> On Sep 14, 2012, at 10:25 AM, Stanislav Kinsbursky wrote:
>
>> Taking hostname from uts namespace if not safe, because this cuold be
>> performind during umount operation on child reaper death. And in this case
>> current->nsproxy is NULL already.
>>
>> Signed-off-by: Stanislav Kinsbursky <skinsbursky@...allels.com>
>> Cc: <stable@...r.kernel.org>
>> ---
>> fs/lockd/mon.c |   14 ++++++++------
>> 1 files changed, 8 insertions(+), 6 deletions(-)
>>
>> diff --git a/fs/lockd/mon.c b/fs/lockd/mon.c
>> index 7ef14b3..c6186fb 100644
>> --- a/fs/lockd/mon.c
>> +++ b/fs/lockd/mon.c
>> @@ -426,11 +426,12 @@ static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
>>   * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
>>   * has changed.
>>   */
>> -static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
>> +static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp,
>> +			 char *nodename)
>> {
>> 	__be32 *p;
>>
>> -	encode_nsm_string(xdr, utsname()->nodename);
>> +	encode_nsm_string(xdr, nodename);
>> 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
>> 	*p++ = cpu_to_be32(argp->prog);
>> 	*p++ = cpu_to_be32(argp->vers);
>> @@ -441,10 +442,11 @@ static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
>>   * The "mon_id" argument specifies the non-private arguments
>>   * of an NSMPROC_MON or NSMPROC_UNMON call.
>>   */
>> -static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
>> +static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp,
>> +			  char *nodename)
>> {
>> 	encode_mon_name(xdr, argp);
>> -	encode_my_id(xdr, argp);
>> +	encode_my_id(xdr, argp, nodename);
>> }
>>
>> /*
>> @@ -463,14 +465,14 @@ static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
>> static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
>> 			    const struct nsm_args *argp)
>> {
>> -	encode_mon_id(xdr, argp);
>> +	encode_mon_id(xdr, argp, req->rq_task->tk_client->cl_nodename);
>
> IMO you should get the cl_nodename in nsm_mon_unmon() from clnt->cl_nodename, and pass it in as part of *argp .  The choice of which nodename to use is clearly a decision for an "upper layer" not a choice for the XDR functions.
>
> Long ago I had patches which fixed this layering violation for a very similar purpose as yours, but they were never applied.
>

I like it. Thanks.

-- 
Best regards,
Stanislav Kinsbursky
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