Re: Opening raw disk while mounted in 5.x?
From: David Andersen (dga+_at_cs.cmu.edu)
Date: 05/25/05
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Date: Wed, 25 May 2005 13:55:41 -0400 To: David Andersen <dga+@cs.cmu.edu>
To answer my own question - this appears to be done in the geom
subsystem now. It can be avoided by enabling the magic foot-shooting
debug flag:
sysctl -w kern.geom.debugflags=16
if you're inclined to shoot yourself in the foot.
-Dave
On May 25, 2005, at 1:10 PM, David Andersen wrote:
> Hoping someone knows the quick answer to this - in 4.x, it was
> possible to open /dev/ad0 while a filesystem one one of its slices was
> mounted. This no longer appears possible under 5.x. Could someone
> point me to the spot in the code where I'd need to disable a
> permissions check (or a sysctl, or anything) to permit this behavior
> again?
>
> (The context: mounting slice 2 of a disk and using it to store a
> compressed filesystem image. Then opening the primary disk device to
> directly write the filesystem image onto slice 1. The kernel seems to
> muck with the write calls if we try to do the write onto slice 1
> instead of the raw disk). This is using the very cool
> imagezip/imageunzip utilities from the Utah Emulab project.
>
> Thanks!
>
> -Dave
>
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- Previous message: Dan Nelson: "Re: Opening raw disk while mounted in 5.x?"
- In reply to: David Andersen: "Opening raw disk while mounted in 5.x?"
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