diff --git a/fs/namespace.c b/fs/namespace.c
index 62899fa..be99e80e 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -1733,6 +1733,11 @@ static struct mnt_namespace *to_mnt_ns(struct ns_common *ns)
 	return container_of(ns, struct mnt_namespace, ns);
 }
 
+struct ns_common *from_mnt_ns(struct mnt_namespace *mnt)
+{
+	return &mnt->ns;
+}
+
 static bool mnt_ns_loop(struct dentry *dentry)
 {
 	/* Could bind mounting the mount namespace inode cause a
diff --git a/fs/nsfs.c b/fs/nsfs.c
index 4f12057..800c1d0 100644
--- a/fs/nsfs.c
+++ b/fs/nsfs.c
@@ -229,6 +229,11 @@ int ns_get_name(char *buf, size_t size, struct task_struct *task,
 	return res;
 }
 
+bool proc_ns_file(const struct file *file)
+{
+	return file->f_op == &ns_file_operations;
+}
+
 struct file *proc_ns_fget(int fd)
 {
 	struct file *file;