by J. Bruce Fields

[permalink] [raw]

Subject: Re: [PATCH 1/1] NFSv4.1: fix lone sequence transport assignment

On Fri, Apr 17, 2020 at 04:53:32PM +0000, Trond Myklebust wrote:
> In RFC5661, Section 18.34.3 I found the following normative text:
>
> Invoking BIND_CONN_TO_SESSION on a connection already associated with
> the specified session has no effect, and the server MUST respond with
> NFS4_OK, unless the client is demanding changes to the set of
> channels the connection is associated with. If so, the server MUST
> return NFS4ERR_INVAL.

Hm, I should fix that.

(Totally untested.)

--b.

commit cd66e66c4ce7
Author: J. Bruce Fields <[email protected]>
Date: Mon Apr 27 17:59:01 2020 -0400

nfsd: handle repeated BIND_CONN_TO_SESSION

If the client attempts BIND_CONN_TO_SESSION on an already bound
connection, it should be either a no-op or an error.

Signed-off-by: J. Bruce Fields <[email protected]>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index a50c045fe7c5..73f821f65ce8 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -3483,6 +3483,45 @@ __be32 nfsd4_backchannel_ctl(struct svc_rqst *rqstp,
return nfs_ok;
}

+static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_session *s)
+{
+ struct nfsd4_conn *c;
+
+ list_for_each_entry(c, &s->se_conns, cn_persession) {
+ if (c->cn_xprt == xpt) {
+ return c;
+ }
+ }
+ return NULL;
+}
+
+static __be32 nfsd4_match_existing_connection(struct svc_rqst *rqst,
+ struct nfsd4_session *session, u32 req)
+{
+ struct nfs4_client *clp = session->se_client;
+ struct svc_xprt *xpt = rqst->rq_xprt;
+ struct nfsd4_conn *c;
+ __be32 status;
+
+ /* Following the last paragraph of RFC 5661 Section 18.34.3: */
+ spin_lock(&clp->cl_lock);
+ c = __nfsd4_find_conn(xpt, session);
+ if (!c)
+ status = nfserr_noent;
+ else if (req == c->cn_flags)
+ status = nfs_ok;
+ else if (req == NFS4_CDFC4_FORE_OR_BOTH &&
+ c->cn_flags != NFS4_CDFC4_BACK)
+ status = nfs_ok;
+ else if (req == NFS4_CDFC4_BACK_OR_BOTH &&
+ c->cn_flags != NFS4_CDFC4_FORE)
+ status = nfs_ok;
+ else
+ status = nfserr_inval;
+ spin_unlock(&clp->cl_lock);
+ return status;
+}
+
__be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
struct nfsd4_compound_state *cstate,
union nfsd4_op_u *u)
@@ -3504,6 +3543,9 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
status = nfserr_wrong_cred;
if (!nfsd4_mach_creds_match(session->se_client, rqstp))
goto out;
+ status = nfsd4_match_existing_connection(rqstp, session, bcts->dir);
+ if (status == nfs_ok || status == nfserr_inval)
+ goto out;
status = nfsd4_map_bcts_dir(&bcts->dir);
if (status)
goto out;
@@ -3569,18 +3611,6 @@ nfsd4_destroy_session(struct svc_rqst *r, struct nfsd4_compound_state *cstate,
return status;
}

-static struct nfsd4_conn *__nfsd4_find_conn(struct svc_xprt *xpt, struct nfsd4_session *s)
-{
- struct nfsd4_conn *c;
-
- list_for_each_entry(c, &s->se_conns, cn_persession) {
- if (c->cn_xprt == xpt) {
- return c;
- }
- }
- return NULL;
-}
-
static __be32 nfsd4_sequence_check_conn(struct nfsd4_conn *new, struct nfsd4_session *ses)
{
struct nfs4_client *clp = ses->se_client;