NFS/SUNRPC: don't lookup machine credential until rpcauth_bindcred().

When NFS creates a machine credential, it is a "generic" credential,
not tied to any auth protocol, and is really just a container for
the princpal name.
This doesn't get linked to a genuine credential until rpcauth_bindcred()
is called.
The lookup always succeeds, so various places that test if the machine
credential is NULL, are pointless.

As a step towards getting rid of generic credentials, this patch gets
rid of generic machine credentials.  The nfs_client and rpc_client
just hold a pointer to a constant principal name.
When a machine credential is wanted, a special static 'struct rpc_cred'
pointer is used. rpcauth_bindcred() recognizes this, finds the
principal from the client, and binds the correct credential.

Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

1 files changed, 2 insertions, 9 deletions

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index cce151776709..fb1cf1a4bda2 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -151,7 +151,6 @@ EXPORT_SYMBOL_GPL(unregister_nfs_version);
 struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
 {
         struct nfs_client *clp;
-        struct rpc_cred *cred;
         int err = -ENOMEM;
 
         if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
@@ -182,9 +181,7 @@ struct nfs_client *nfs_alloc_client(const struct nfs_client_initdata *cl_init)
         clp->cl_proto = cl_init->proto;
         clp->cl_net = get_net(cl_init->net);
 
-        cred = rpc_lookup_machine_cred("*");
-        if (!IS_ERR(cred))
-                clp->cl_machine_cred = cred;
+        clp->cl_principal = "*";
         nfs_fscache_get_client_cookie(clp);
 
         return clp;
@@ -246,11 +243,6 @@ void nfs_free_client(struct nfs_client *clp)
         if (!IS_ERR(clp->cl_rpcclient))
                 rpc_shutdown_client(clp->cl_rpcclient);
 
-        if (clp->cl_machine_cred != NULL)
-                put_rpccred(clp->cl_machine_cred);
-        if (clp->cl_root_cred != NULL)
-                put_rpccred(clp->cl_root_cred);
-
         put_net(clp->cl_net);
         put_nfs_version(clp->cl_nfs_mod);
         kfree(clp->cl_hostname);
@@ -529,6 +521,7 @@ int nfs_create_rpc_client(struct nfs_client *clp,
                 return PTR_ERR(clnt);
         }
 
+        clnt->cl_principal = clp->cl_principal;
         clp->cl_rpcclient = clnt;
         return 0;
 }