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Date: Tue, 27 Jun 2006 19:17:27 -0700
From: Andrew Morton <akpm@osdl.org>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: linux-kernel@vger.kernel.org, herbert@13thfloor.at, viro@ftp.linux.org.uk,
       serue@us.ibm.com
Subject: Re: [PATCH 00/20] Mount writer count and read-only bind mounts (v3)
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On Tue, 27 Jun 2006 18:50:36 -0700
Dave Hansen <haveblue@us.ibm.com> wrote:

> > > Since the last revision, the locking in faccessat() and
> > > mnt_is_readonly() has been changed to fix a race which might have
> > > caused a false-negative mount-is-readonly return when faccessat()
> > > is called while another two processes are racing to make a mount
> > > readonly.
> > > 
> > umm, what's it all for?
> 
> Mostly for vserver, for now.  They allow a filesystem to be r/w, but
> have r/o views into it.  This is really handy so that every vserver can
> use a common install but still allow the administrator to update it.

OK.  That makes it one of those features which stays in -mm until we work
out what we're going to do about containers/vserver/etc.

Unless there's something else which needs it?

This is all rather important info, you know.  It should be presented
front-and-centre in [patch 0/N].  In detail...