NFS: Fix following referral mount points with different security

I create a new proc_lookup_mountpoint() to use when submounting an NFS
v4 share.  This function returns an rpc_clnt to use for performing an
fs_locations() call on a referral's mountpoint.

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

1 files changed, 34 insertions, 10 deletions

diff --git a/fs/nfs/namespace.c b/fs/nfs/namespace.c
index 1807866..b9a593d 100644
--- a/fs/nfs/namespace.c
+++ b/fs/nfs/namespace.c
@@ -200,6 +200,22 @@ out_shutdown:
 out:
 	return err;
 }
+
+static struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
+					      struct qstr *name,
+					      struct nfs_fh *fh,
+					      struct nfs_fattr *fattr)
+{
+	int err;
+
+	if (NFS_PROTO(dir)->version == 4)
+		return nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
+
+	err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
+	if (err)
+		return ERR_PTR(err);
+	return rpc_clone_client(NFS_SERVER(dir)->client);
+}
 #else /* CONFIG_NFS_V4 */
 static inline int nfs_lookup_with_sec(struct nfs_server *server,
 				      struct dentry *parent, struct dentry *dentry,
@@ -209,6 +225,17 @@ static inline int nfs_lookup_with_sec(struct nfs_server *server,
 {
 	return -EPERM;
 }
+
+static inline struct rpc_clnt *nfs_lookup_mountpoint(struct inode *dir,
+						     struct qstr *name,
+						     struct nfs_fh *fh,
+						     struct nfs_fattr *fattr)
+{
+	int err = NFS_PROTO(dir)->lookup(NFS_SERVER(dir)->client, dir, name, fh, fattr);
+	if (err)
+		return ERR_PTR(err);
+	return rpc_clone_client(NFS_SERVER(dir)->client);
+}
 #endif /* CONFIG_NFS_V4 */
 
 /*
@@ -226,11 +253,10 @@ static inline int nfs_lookup_with_sec(struct nfs_server *server,
 struct vfsmount *nfs_d_automount(struct path *path)
 {
 	struct vfsmount *mnt;
-	struct nfs_server *server = NFS_SERVER(path->dentry->d_inode);
 	struct dentry *parent;
 	struct nfs_fh *fh = NULL;
 	struct nfs_fattr *fattr = NULL;
-	int err;
+	struct rpc_clnt *client;
 	rpc_authflavor_t flavor = RPC_AUTH_UNIX;
 
 	dprintk("--> nfs_d_automount()\n");
@@ -249,21 +275,19 @@ struct vfsmount *nfs_d_automount(struct path *path)
 
 	/* Look it up again to get its attributes */
 	parent = dget_parent(path->dentry);
-	err = server->nfs_client->rpc_ops->lookup(server->client, parent->d_inode,
-						  &path->dentry->d_name,
-						  fh, fattr);
-	if (err == -EPERM && NFS_PROTO(parent->d_inode)->secinfo != NULL)
-		err = nfs_lookup_with_sec(server, parent, path->dentry, path, fh, fattr, &flavor);
+	client = nfs_lookup_mountpoint(parent->d_inode, &path->dentry->d_name, fh, fattr);
 	dput(parent);
-	if (err != 0) {
-		mnt = ERR_PTR(err);
+	if (IS_ERR(client)) {
+		mnt = ERR_CAST(client);
 		goto out;
 	}
 
 	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL)
-		mnt = nfs_do_refmount(path->dentry);
+		mnt = nfs_do_refmount(client, path->dentry);
 	else
 		mnt = nfs_do_submount(path->dentry, fh, fattr, flavor);
+	rpc_shutdown_client(client);
+
 	if (IS_ERR(mnt))
 		goto out;