Re: [PATCH 00/20] Mount writer count and read-only bind mounts (v3)

[Arjan van de Ven]

On Tue, 2006-06-27 at 19:17 -0700, Andrew Morton wrote:
> On Tue, 27 Jun 2006 18:50:36 -0700
> Dave Hansen <haveblue@xxxxxxxxxx> 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?

in a previous life we repeatedly had customers who really wanted this.
It's more than just containers; it's chroots too (arguably that's
containers as well but a lot more common deployed today) but also things
where the customer wanted to mount a part of a network mount as /usr,
but read only just to be sure....


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