From: Rob Landley <rob@landley.net>
Organization: Boundaries Unlimited
To: David Leimbach <leimy2k@gmail.com>
Subject: Re: /etc/mtab and per-process namespaces
Date: Wed, 19 Oct 2005 22:42:03 -0500
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On Sunday 02 October 2005 17:08, David Leimbach wrote:
> I've been just playing around with the v9fs work and private
> namespaces from yesterday's [October 1, 2005] top of tree from Linus'
> git archive and I was looking at /etc/mtab's reaction to having
> multiple namespaces with bind mounts.

Oh you don't need namespaces to hork mtab.  Do a mount from a chroot 
environment.  Or try to use --bind or --move mounts (at all) and watch it beg 
for mercy.  (I accidentally ran UserMode Linux as root once, using a hostfs 
root filesystem to borrow the existing Linux's root filesystem, and its' 
mounts edited the parent system's /etc/mtab.  Yeah, that was user error on my 
part, but it's also the _only_ gotcha I've found when doing that.)

/etc/mtab is simply brittle.  Personally, on systems I build, I ln 
-s /proc/mounts /etc/mtab

Rob
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