nfsd4: use common rpc_cred for all callbacks

Callbacks are always made using the machine's identity, so we can use a
single auth_generic credential shared among callbacks to all clients and
let the rpc code take care of the rest.

Signed-off-by: J. Bruce Fields <bfields@citi.umich.edu>

3 files changed, 12 insertions, 29 deletions

diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
index 4abb88264c72..128519769ea8 100644
--- a/fs/nfsd/nfs4callback.c
+++ b/fs/nfsd/nfs4callback.c
@@ -432,42 +432,29 @@ static const struct rpc_call_ops nfsd4_cb_probe_ops = {
         .rpc_call_done = nfsd4_cb_probe_done,
 };
 
-static struct rpc_cred *lookup_cb_cred(struct nfs4_cb_conn *cb)
+static struct rpc_cred *callback_cred;
+
+int set_callback_cred(void)
 {
-        struct auth_cred acred = {
-                .machine_cred = 1
-        };
-        struct rpc_auth *auth = cb->cb_client->cl_auth;
-
-        /*
-         * Note in the gss case this doesn't actually have to wait for a
-         * gss upcall (or any calls to the client); this just creates a
-         * non-uptodate cred which the rpc state machine will fill in with
-         * a refresh_upcall later.
-         */
-        return auth->au_ops->lookup_cred(auth, &acred, RPCAUTH_LOOKUP_NEW);
+        callback_cred = rpc_lookup_machine_cred();
+        if (!callback_cred)
+                return -ENOMEM;
+        return 0;
 }
 
+
 void do_probe_callback(struct nfs4_client *clp)
 {
         struct nfs4_cb_conn *cb = &clp->cl_cb_conn;
         struct rpc_message msg = {
                 .rpc_proc       = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL],
                 .rpc_argp       = clp,
+                .rpc_cred       = callback_cred
         };
-        struct rpc_cred *cred;
         int status;
 
-        cred = lookup_cb_cred(cb);
-        if (IS_ERR(cred)) {
-                status = PTR_ERR(cred);
-                goto out;
-        }
-        cb->cb_cred = cred;
-        msg.rpc_cred = cb->cb_cred;
         status = rpc_call_async(cb->cb_client, &msg, RPC_TASK_SOFT,
                                 &nfsd4_cb_probe_ops, (void *)clp);
-out:
         if (status) {
                 warn_no_callback_path(clp, status);
                 put_nfs4_client(clp);
@@ -550,7 +537,7 @@ nfsd4_cb_recall(struct nfs4_delegation *dp)
         struct rpc_message msg = {
                 .rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL],
                 .rpc_argp = dp,
-                .rpc_cred = clp->cl_cb_conn.cb_cred
+                .rpc_cred = callback_cred
         };
         int status;
 
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 11db40cb2f2b..0445192d660d 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -696,10 +696,6 @@ shutdown_callback_client(struct nfs4_client *clp)
                 clp->cl_cb_conn.cb_client = NULL;
                 rpc_shutdown_client(clnt);
         }
-        if (clp->cl_cb_conn.cb_cred) {
-                put_rpccred(clp->cl_cb_conn.cb_cred);
-                clp->cl_cb_conn.cb_cred = NULL;
-        }
 }
 
 static inline void
@@ -4020,7 +4016,7 @@ __nfs4_state_start(void)
                 return -ENOMEM;
         queue_delayed_work(laundry_wq, &laundromat_work, grace_time);
         set_max_delegations();
-        return 0;
+        return set_callback_cred();
 }
 
 int
diff --git a/include/linux/nfsd/state.h b/include/linux/nfsd/state.h
index 70ef5f4abbbc..9bf3aa8c5aea 100644
--- a/include/linux/nfsd/state.h
+++ b/include/linux/nfsd/state.h
@@ -89,7 +89,6 @@ struct nfs4_cb_conn {
         /* RPC client info */
         atomic_t                cb_set;     /* successful CB_NULL call */
         struct rpc_clnt *       cb_client;
-        struct rpc_cred *       cb_cred;
 };
 
 /* Maximum number of slots per session. 160 is useful for long haul TCP */
@@ -362,6 +361,7 @@ extern int nfs4_in_grace(void);
 extern __be32 nfs4_check_open_reclaim(clientid_t *clid);
 extern void put_nfs4_client(struct nfs4_client *clp);
 extern void nfs4_free_stateowner(struct kref *kref);
+extern int set_callback_cred(void);
 extern void nfsd4_probe_callback(struct nfs4_client *clp);
 extern void nfsd4_cb_recall(struct nfs4_delegation *dp);
 extern void nfs4_put_delegation(struct nfs4_delegation *dp);