namespace: extract show_path() helper

To be used by the statmount(2) syscall as well.

Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Link: https://lore.kernel.org/r/20231025140205.3586473-4-mszeredi@redhat.com
Reviewed-by: Ian Kent <raven@themaw.net>
Signed-off-by: Christian Brauner <brauner@kernel.org>
diff --git a/fs/internal.h b/fs/internal.h
index 58e43341..16bfe50 100644
--- a/fs/internal.h
+++ b/fs/internal.h
@@ -83,6 +83,8 @@ int path_mount(const char *dev_name, struct path *path,
 		const char *type_page, unsigned long flags, void *data_page);
 int path_umount(struct path *path, int flags);
 
+int show_path(struct seq_file *m, struct dentry *root);
+
 /*
  * fs_struct.c
  */