From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH 8/9] overlay: overlay filesystem documentation
Date: Wed, 13 Mar 2013 16:06:23 -0700
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To: Miklos Szeredi <miklos@szeredi.hu>
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On Wed, 13 Mar 2013 15:16:32 +0100 Miklos Szeredi <miklos@szeredi.hu> wrote:

> From: Neil Brown <neilb@suse.de>
> 
> Document the overlay filesystem.
> 

Damn, I did it again.  This is good, thanks.

> +Changes to the underlying filesystems while part of a mounted overlay
> +filesystem are not allowed.  If the underlying filesystem is changed,
> +the behavior of the overlay is undefined, though it will not result in
> +a crash or deadlock.

ah-hah, there it is.  I was wondering how this can-o-worms would be
handled ;)

Is there anything in place to enforce this at runtime?  Checks for
read-onlyness, code to prevent rw remounts, etc?