SUNRPC: Ensure that rpc_mkpipe returns a refcounted dentry

If not, we cannot guarantee that idmap->idmap_dentry, gss_auth->dentry and
clnt->cl_dentry are valid dentries.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/net/sunrpc/rpc_pipe.c b/net/sunrpc/rpc_pipe.c
index 567abbe..72b2217 100644
--- a/net/sunrpc/rpc_pipe.c
+++ b/net/sunrpc/rpc_pipe.c
@@ -669,7 +669,7 @@
 out:
 	mutex_unlock(&dir->i_mutex);
 	rpc_release_path(&nd);
-	return dentry;
+	return dget(dentry);
 err_depopulate:
 	rpc_depopulate(dentry);
 	__rpc_rmdir(dir, dentry);
@@ -733,7 +733,7 @@
 out:
 	mutex_unlock(&dir->i_mutex);
 	rpc_release_path(&nd);
-	return dentry;
+	return dget(dentry);
 err_dput:
 	dput(dentry);
 	dentry = ERR_PTR(-ENOMEM);