Fix user namespace leak

Fixes: 61ca2c4afd ("NFS: Only reference user namespace from nfs4idmap struct instead of cred")
Signed-off-by: Alexey Gladkov <legion@kernel.org>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>

fs/nfs/nfs4idmap.c

@@ -487,7 +487,7 @@ nfs_idmap_new(struct nfs_client *clp)
 err_destroy_pipe:
 	rpc_destroy_pipe_data(idmap->idmap_pipe);
 err:
-	get_user_ns(idmap->user_ns);
+	put_user_ns(idmap->user_ns);
 	kfree(idmap);
 	return error;
 }