SUNRPC: Add a helper rpcauth_lookup_generic_cred()

The NFSv4 protocol allows clients to negotiate security protocols on the
fly in the case where an administrator on the server changes the export
settings and/or in the case where we may have a filesystem migration event.

Instead of having the NFS client code cache credentials that are tied to a
particular AUTH method it is therefore preferable to have a generic credential
that can be converted into whatever AUTH is in use by the RPC client when
the read/write/sillyrename/... is put on the wire.

We do this by means of the new "generic" credential, which basically just
caches the minimal information that is needed to look up an RPCSEC_GSS,
AUTH_SYS, or AUTH_NULL credential.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index bbb0d58ee6ac..f38d0573be18 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1408,7 +1408,7 @@ nfs4_atomic_open(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
                 BUG_ON(nd->intent.open.flags & O_CREAT);
         }
 
-        cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
+        cred = rpc_lookup_cred();
         if (IS_ERR(cred))
                 return (struct dentry *)cred;
         parent = dentry->d_parent;
@@ -1443,7 +1443,7 @@ nfs4_open_revalidate(struct inode *dir, struct dentry *dentry, int openflags, st
         struct rpc_cred *cred;
         struct nfs4_state *state;
 
-        cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
+        cred = rpc_lookup_cred();
         if (IS_ERR(cred))
                 return PTR_ERR(cred);
         state = nfs4_do_open(dir, &path, openflags, NULL, cred);
@@ -1660,7 +1660,7 @@ nfs4_proc_setattr(struct dentry *dentry, struct nfs_fattr *fattr,
 
         nfs_fattr_init(fattr);
         
-        cred = rpcauth_lookupcred(NFS_CLIENT(inode)->cl_auth, 0);
+        cred = rpc_lookup_cred();
         if (IS_ERR(cred))
                 return PTR_ERR(cred);
 
@@ -1896,7 +1896,7 @@ nfs4_proc_create(struct inode *dir, struct dentry *dentry, struct iattr *sattr,
         struct rpc_cred *cred;
         int status = 0;
 
-        cred = rpcauth_lookupcred(NFS_CLIENT(dir)->cl_auth, 0);
+        cred = rpc_lookup_cred();
         if (IS_ERR(cred)) {
                 status = PTR_ERR(cred);
                 goto out;