From mboxrd@z Thu Jan  1 00:00:00 1970
From: Al Viro <viro-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
Subject: Re: [PATCH review 5/6] vfs: Test for and handle paths that are
	unreachable from their mnt_root
Date: Mon, 10 Aug 2015 05:38:14 +0100
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On Mon, Aug 03, 2015 at 04:30:22PM -0500, Eric W. Biederman wrote:

> +	if (!is_subdir(nd->path.dentry, mnt->mnt_root))
> +		return false;

Umm...  What's to protect us from racing with d_move() right here?