nfsd4: simplify bind_conn_to_session locking

The locking here is very fiddly, and there's no reason for us to be
setting cstate->session, since this is the only op in the compound.
Let's just take the state lock and drop the reference counting.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 8cc668dc4997fb9cf22da80ef369fba7cb897adc..8e83cef4d0bdb0a8730b6b2460e30f5c1be3fd23 100644 (file)
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -1887,30 +1887,30 @@ __be32 nfsd4_bind_conn_to_session(struct svc_rqst *rqstp,
 {
        __be32 status;
        struct nfsd4_conn *conn;
+       struct nfsd4_session *session;
        struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
        if (!nfsd4_last_compound_op(rqstp))
                return nfserr_not_only_op;
+       nfs4_lock_state();
        spin_lock(&nn->client_lock);
-       cstate->session = find_in_sessionid_hashtbl(&bcts->sessionid, SVC_NET(rqstp));
-       /* Sorta weird: we only need the refcnt'ing because new_conn acquires
-        * client_lock iself: */
-       if (cstate->session) {
-               nfsd4_get_session(cstate->session);
-               atomic_inc(&cstate->session->se_client->cl_refcount);
-       }
+       session = find_in_sessionid_hashtbl(&bcts->sessionid, SVC_NET(rqstp));
        spin_unlock(&nn->client_lock);
-       if (!cstate->session)
-               return nfserr_badsession;
-
+       status = nfserr_badsession;
+       if (!session)
+               goto out;
        status = nfsd4_map_bcts_dir(&bcts->dir);
        if (status)
-               return status;
+               goto out;
        conn = alloc_conn(rqstp, bcts->dir);
+       status = nfserr_jukebox;
        if (!conn)
-               return nfserr_jukebox;
-       nfsd4_init_conn(rqstp, conn, cstate->session);
-       return nfs_ok;
+               goto out;
+       nfsd4_init_conn(rqstp, conn, session);
+       status = nfs_ok;
+out:
+       nfs4_unlock_state();
+       return status;
 }
 
 static bool nfsd4_compound_in_session(struct nfsd4_session *session, struct nfs4_sessionid *sid)