Re: new shutdown order

[David Young <dyoung%pobox.com@localhost>]

On Mon, Apr 20, 2009 at 11:13:06PM -0400, der Mouse wrote:
> >         1 Try to "gently" unmount all filesystems.
> >         2 Try to detach all devices and pseudo-devices.
> >         3 If step 1 or step 2 detached any device or filesystem, goto
> >           step 1.  Otherwise, continue.
> >         4 Try to forcefully unmount a filesystem.
> >         5 Try to detach all devices and pseudo-devices.
> >         6 If step 4 or step 5 detached any device or filesystem, goto
> >           step 4.  Otherwise, end.
> 
> I would say goto step 1, not step 4, in step 6 - once you force an
> unmount, a bunch more stuff may unstack without needing
> sledgehammering.

Oh!  Thanks for pointing that out.  I will try to avoid the
sledgehammer.

> As you point out in another message, you really want to pick the
> "topmost" filesystem to force-unmount in step 4, but it's not at all
> clear how to find that programmatically; something must be held active
> or it would have unmounted gently, and it's not obvious how to
> determine which is the best unmount to force.

Greg Oster suggested adding a timestamp or generation number to each
mount, scanning for and forcing the unmount of only the most recent
mount.  Works for me. :-)

Dave

-- 
David Young             OJC Technologies
dyoung%ojctech.com@localhost      Urbana, IL * (217) 278-3933