Date: Fri, 1 May 2015 02:55:24 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: NeilBrown <neilb@suse.de>
Cc: "J. Bruce Fields" <bfields@fieldses.org>,
        Kinglong Mee <kinglongmee@gmail.com>,
        "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH RFC] NFSD: fix cannot umounting mount points under pseudo
 root
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On Thu, Apr 30, 2015 at 07:52:25AM +1000, NeilBrown wrote:

> An alternative might be to stop using lookup_one_len, and use kern_path()
> instead.  Or kern_path_mountpoint if we don't want to cross a mountpoint.

NAK.  This is a monumentally bad idea - please, do not do it.  Not to mention
anything else, kern_path() is a _lot_ heavier, including much worse stack
footprint.