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From: Joe Greco <jgreco@brasil.moneng.mei.com>
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Subject: Re: Nightmare.
To: terry@lambert.org (Terry Lambert)
Date: Wed, 14 Aug 1996 12:21:10 -0500 (CDT)
Cc: jgreco@brasil.moneng.mei.com, ulf@lamb.net, jkh@time.cdrom.com,
        hackers@freebsd.org
In-Reply-To: <199608141710.KAA29273@phaeton.artisoft.com> from "Terry Lambert" at Aug 14, 96 10:10:48 am
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> > > I would go more into the direction of checking if the dump device is a
> > > mounted file system. Easy check. 
> > 
> > I tend to agree, but wonder if it would not make more sense to tackle this
> > from a different angle.
> > 
> > Consider all the programs that could clobber a mounted file system.  Would
> > it make more sense if we somehow protected a mounted disk device from
> > being clobbered?
> 
> Yes.  Disable the raw device for mounted disks.  The stacking
> architecture disallows (since it internall references the vnodes) a
> device level soloution that does anything to the non-raw device.
> 
> If we can get past the point where devfs is a mandatory item, then we
> can fix all of this without breaking FS stacking.  There is no soloution
> otherwise that could not be broken by a clever idiot.

Would it make more sense to just disable _writes_ to raw devices for mounted
disks?  (probably writes to both devices, for that matter)

I am thinking specifically of using dump,dd,etc to read a mounted file
system for some useful purpose.

... JG