Re: [PATCH 1/3] lockd: use rpc client's cl_nodename for id encoding

[Stanislav Kinsbursky]

14.09.2012 23:08, Chuck Lever ÐÐÑÐÑ:
> 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@xxxxxxxxxxxxx>
> > Cc: <stable@xxxxxxxxxxxxxxx>
> > ---
> > 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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