Bug#239111: Grub is shockingly bad code

[Robert McQueen]

Robert Millan wrote:
> Rob,
> 
> Did you hit this problem when installing GRUB to a partition, or to the
> whole disk?

I was upgrading from etch to lenny on a box where / is XFS and /boot and
/var are on the same partition. GRUB is installed into the MBR. I know
you can't install bootloaders onto XFS partitions.

(If that had happened, based on previous experience the FS would've
panicked and all IO returned with an error, so I'd probably have been
able to log in and get a lot of errors, assuming bash was still in the
cache. :D)

So no, it's nothing to do with where I'm trying to install GRUB to, the
problem is the Debian patch to grub-install did xfs_freeze on my root
filesystem and then did various crap including trying to write to the
log file (and make a /boot/grub/default file, I think?), all of which go
into D state while the filesystem is frozen so don't finish, and
meanwhile everything else on my system ground to a halt too. Obviously
hard for me to debug given I lost all my access to the system, but
asking SysRq for backtraces showed everything was blocked on FS access.
(Actually as a result of my experience I think XFS devs are adding an
unfreeze SysRq atm...)

Just make the script not try do anything at all which might potentially
cause a write to the filesystem while it's frozen, is the main thing...
Backing out the bullshit XFS Debian patch would do that, applying Ben's
might even make it work properly on lenny.

Regards,
Rob