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From:   Chuck Lever III <chuck.lever@oracle.com>
To:     Bruce Fields <bfields@fieldses.org>
CC:     Linux NFS Mailing List <linux-nfs@vger.kernel.org>,
        David Wysochanski <dwysocha@redhat.com>
Subject: Re: [PATCH RFC 21/21] NFSD: Add tracepoints to observe clientID
 activity
Thread-Topic: [PATCH RFC 21/21] NFSD: Add tracepoints to observe clientID
 activity
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Date:   Tue, 11 May 2021 15:59:00 +0000
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As Dave reported yesterday, this patch is unfinished and is probably
junk. But any thoughts on how the tracepoints should be organized
in this code would help.

So I was thinking we probably want a tracepoint to fire for each
case that is handled in this code (and in nfsd4_exchangeid).
However, this comment in nfsd4_setclientid:

   /* Cases below refer to rfc 3530 section 14.2.33: */

Is confusing.

- RFC 3530 is superceded by RFC 7530, and the section numbers have changed.

- The cases in this section in both RFCs aren't numbered, they are
bullet points.


> On May 10, 2021, at 11:53 AM, Chuck Lever <chuck.lever@oracle.com> wrote:
>=20
> We are especially interested in capturing clientID conflicts.
>=20
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
> fs/nfsd/nfs4state.c |    9 +++++++--
> fs/nfsd/trace.h     |   37 +++++++++++++++++++++++++++++++++++++
> 2 files changed, 44 insertions(+), 2 deletions(-)
>=20
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index a61601fe422a..528cabffa1e9 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -3180,6 +3180,7 @@ nfsd4_exchange_id(struct svc_rqst *rqstp, struct nf=
sd4_compound_state *cstate,
> 			}
> 			/* case 6 */
> 			exid->flags |=3D EXCHGID4_FLAG_CONFIRMED_R;
> +			trace_nfsd_clid_existing(conf);
> 			goto out_copy;
> 		}
> 		if (!creds_match) { /* case 3 */
> @@ -3188,15 +3189,18 @@ nfsd4_exchange_id(struct svc_rqst *rqstp, struct =
nfsd4_compound_state *cstate,
> 				trace_nfsd_clid_cred_mismatch(conf, rqstp);
> 				goto out;
> 			}
> +			trace_nfsd_clid_new(new);
> 			goto out_new;
> 		}
> 		if (verfs_match) { /* case 2 */
> 			conf->cl_exchange_flags |=3D EXCHGID4_FLAG_CONFIRMED_R;
> +			trace_nfsd_clid_existing(conf);
> 			goto out_copy;
> 		}
> 		/* case 5, client reboot */
> 		trace_nfsd_clid_verf_mismatch(conf, rqstp, &verf);
> 		conf =3D NULL;
> +		trace_nfsd_clid_new(new);
> 		goto out_new;
> 	}
>=20
> @@ -3996,10 +4000,12 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct =
nfsd4_compound_state *cstate,
> 		if (same_verf(&conf->cl_verifier, &clverifier)) {
> 			copy_clid(new, conf);
> 			gen_confirm(new, nn);
> +			trace_nfsd_clid_existing(new);
> 		} else
> 			trace_nfsd_clid_verf_mismatch(conf, rqstp,
> 						      &clverifier);
> -	}
> +	} else
> +		trace_nfsd_clid_new(new);
> 	new->cl_minorversion =3D 0;
> 	gen_callback(new, setclid, rqstp);
> 	add_to_unconfirmed(new);
> @@ -4017,7 +4023,6 @@ nfsd4_setclientid(struct svc_rqst *rqstp, struct nf=
sd4_compound_state *cstate,
> 	return status;
> }
>=20
> -
> __be32
> nfsd4_setclientid_confirm(struct svc_rqst *rqstp,
> 			struct nfsd4_compound_state *cstate,
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index 523045c37749..6ddff13e3181 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -626,6 +626,43 @@ TRACE_EVENT(nfsd_clid_verf_mismatch,
> 	)
> );
>=20
> +DECLARE_EVENT_CLASS(nfsd_clid_class,
> +	TP_PROTO(const struct nfs4_client *clp),
> +	TP_ARGS(clp),
> +	TP_STRUCT__entry(
> +		__field(u32, cl_boot)
> +		__field(u32, cl_id)
> +		__array(unsigned char, addr, sizeof(struct sockaddr_in6))
> +		__field(unsigned long, flavor)
> +		__array(unsigned char, verifier, NFS4_VERIFIER_SIZE)
> +		__field(unsigned int, namelen)
> +		__dynamic_array(unsigned char, name, clp->cl_name.len)
> +	),
> +	TP_fast_assign(
> +		memcpy(__entry->addr, &clp->cl_addr,
> +			sizeof(struct sockaddr_in6));
> +		__entry->flavor =3D clp->cl_cred.cr_flavor;
> +		memcpy(__entry->verifier, (void *)&clp->cl_verifier,
> +		       NFS4_VERIFIER_SIZE);
> +		__entry->namelen =3D clp->cl_name.len;
> +		memcpy(__get_dynamic_array(name), clp->cl_name.data,
> +			clp->cl_name.len);
> +	),
> +	TP_printk("addr=3D%pISpc name=3D'%.*s' verifier=3D0x%s flavor=3D%s clie=
nt=3D%08x:%08x\n",
> +		__entry->addr, __entry->namelen, __get_str(name),
> +		__print_hex_str(__entry->verifier, NFS4_VERIFIER_SIZE),
> +		show_nfsd_authflavor(__entry->flavor),
> +		__entry->cl_boot, __entry->cl_id)
> +);
> +
> +#define DEFINE_CLID_EVENT(name) \
> +DEFINE_EVENT(nfsd_clid_class, nfsd_clid_##name, \
> +	TP_PROTO(const struct nfs4_client *clp), \
> +	TP_ARGS(clp))
> +
> +DEFINE_CLID_EVENT(new);
> +DEFINE_CLID_EVENT(existing);
> +
> /*
>  * from fs/nfsd/filecache.h
>  */
>=20
>=20

--
Chuck Lever