Re: [dm-crypt] FYI: how to (really) cleanly shutdown the system when root is on multiple stacked block devices

[Arno Wagner <arno@wagner.name>]

On Sun, Jun 27, 2010 at 01:13:01AM +0200, Christoph Anton Mitterer wrote:
> On Sat, 2010-06-26 at 21:24 +0200, Milan Broz wrote:
> > fsycn currently in kerenl issues barrier in block layer and then waits for it.
> > 
> > But if because ever reads can cause some metadata updates (last access on file stamp),
> > remounting read-only is there.
> Just hope that init-systems like sysvinit are really guaranteed to wait
> for each of their scripts (and therefore for the blocked umount).
> Otherwise they could kill it,.. and while the umount would be still
> there and blocked,... it could go on to the next (halt/reboot).
> 
> :/

Hmm. You know, encrypted root is a problem and pretty difficult
to do in the rfirt place. Why not just encrypt the critical 
parts, like /var /home /root? The rest only holds binaries
and config files anyways, which are not that sensitive...

However, from my experience you cannot actually kill -9
umount/remoute-ro (had a problem with some drive...), 
but either have to wait it out or do a physical reset or
power cycle.

Arno
-- 
Arno Wagner, Dr. sc. techn., Dipl. Inform., CISSP -- Email: arno@wagner.name 
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