Re: retiring device.map

[Robert Millan]

On Tue, May 06, 2008 at 11:43:48AM -0400, Pavel Roskin wrote:
> On Tue, 2008-05-06 at 17:18 +0200, Robert Millan wrote:
> 
> > I completely agree.  How do we go about this?  First of all we need support
> > for labels, right?
> 
> We have it already in the "search" command.  Of course, there is always
> room for improvement.  GRUB doesn't recognize Linux swap labels.  It
> cannot set root to, say, partition 3 on a disk where partition 1 has the
> given label.

Sorry, I was confusing labels with UUIDs.  The problem with labels is they're
not garanteed to be unique, right?  So maybe we need support for UUIDs..

> Anyway, the fix belongs to the installer.  The first step would be not
> to use device.map is it's not needed.  In other words, if it's not a
> cross-device install, don't read device.map and don't try to create it.

I think this isn't an easy as it looks.  grub-setup works much like grub-emu
in that it uses code from outside util/, which only understands devices when
represented in GRUB syntax.

Maybe we could force-feed it something like "(/dev/something)" as if it
were a GRUB drive, but then how would it know how are partitions represented
by the OS?  (%d, p%d, etc)

> Finally, update-grub should be modified to look for partitions by
> labels.

We can do this already, without changing how device.map works.  Though, we
need to reuse the same code in GRUB to obtain the labels (for robustness),
which would need some new option in grub-probe or so.

-- 
Robert Millan

<GPLv2> I know my rights; I want my phone call!
<DRM> What use is a phone call… if you are unable to speak?
(as seen on /.)