Re: Total And Complete Wackyness

[Peter T. Breuer]

"A month of sundays ago [e-mail] wrote:"
> Guus Sliepen <[e-mail]> wrote:
> > [re: layering a protocol over a block device]
> >
> > This MAY sound like fiction, but this is already a problem with raid (just
> > mount a raid over /dev/hda1..4, you still can access or mount hda1..hda4
> > seperately).
> 
> > Hmz, MIT magic cookies ;)?
> 
> 	Vhat are deez, ``Majeek cookees''?
> 
>   Seriously, what is the MIT magic cookies approach? Do you have a 
> terse explanation, or a good URL? I'd love to hear it.

It leaves a lot to the imagination ...

My yoke device already fixes some of the problem with leaving devices
accessible under a raid mirror, by simply not requiring any overlying
device. It hooks together the raw devices, hijacking their request_fn's
in the kernel, and doing other bits of cuckoo-type things. (uh,
probably available via www.freshmeat.net; /yoke).

But I don't see why part of the action of the ordinary raid device
couldn't be to do the same thing in reverse .. disable access via the
underlying devices. I might suggest a patch in a while (soon
as I can get hold of a recent kernel source). It should probably
stash the ops structure already registerered for the device
and substitute its own. To check .. if raid depends on the strcuture
being available just where it used to be ...

Peter