Bug#488687: partman-crypto: Broken when using multiple disks

[Frans Pop <elendil@planet.nl>]

On Saturday 05 July 2008, =?UTF-8?Q?J=C3=A9r=C3=A9my?= Bobbio wrote:
> The attached patch changes partman_lock_unit() and
> partman_unlock_unit() to restore the current directory once their job
> is done.  I am not commiting this patch directly as I doubt it to be
> the best way to do this.

Looks fairly clean and as I would not expect these functions to become 
much more complicated I think it's OK.

> One could argue that a pair of parenthesis could be put around the call
> to partman_lock_unit() in setup_cryptdev(); please reassign the bug
> back to partman-crypto if that feels more desirable.

Instead of relying on all callers to do that, I'd prefer to see the 
functions themselves start a subshell. That would be a good alternative 
to saving cwd.

I'm not sure if a subshell is really to be preferred over the saving cwd 
or not.