This ended up being easier than I thought. I booted into a rescue cd,
and I just mounted the partition with my root filesystem on it
directly using "mount /dev/sdb3 /mnt", since the current snapshot is
the default subvolume, the root filesystem mounted. I then used the
standard way to bind everything that needed binding, and then after
doing the chroot, I just ran a "mount -a", and since I had already
done the chroot, the mount -a used the fstab and the correct mount
points. I then just reverted to the old /etc/default/grub config file
and then used grub2-mkconfig and grub2-install and for good measure, I
also did a dracut -f, but I'm not sure it was necessary.
I still don't know the root of the issue, but this seems to have
resolved things to my satisfaction. I've attached a copy of the
/etc/default/grub.rpmnew file that I got after the update. I'm sure
the error lies there, but I don't know what it is. Note the only thing
that changed from what I got after the zypper dup is
GRUB_CMDLINE_LINUX_DEFAULT="resume=/dev/sda2 splash=silent quiet
showopts intel_iommu=on iommu=pt"
which I added myself through yast. If anyone who knows what they are
looking at and wants to figure out what borked the installation, feel
free to let me know. I'm satisfied with just getting things working
again.
Thanks everyone who took time to respond.
Michael
On Fri, Feb 9, 2018 at 3:16 PM, Carlos E. R.
On 2018-02-09 19:28, Michael Albert wrote:
Thanks for the response. I've done the standard chroot thing before to fix boot issues on other file systems, but the problem with btrfs is that there are a bunch of different subvolumes for different folders that are a part of root.
I see. :-(
The issue I'm having is that I don't know what needs to be mounted and what doesn't in order to repair grub. Nor am I certain what the right way to repair grub is in this particular situation; this is a brand new kind of problem for me and I don't know how it happened. Is it just something like:
grub2-mkconfig -o /boot/grub2/grub.cfg; grub2-install /dev/sda;
?
Do I need to do a dracut -f afterwards?
I think you only need the first one, but on doubt, just use yast bootloader module and change the timeout one second to force it write it all.
I've got all of the old config files (I save this in a slightly more labor intensive manner than you, so I do save them). I can restore the old /etc/default/grub file and then try to repair grub, I just don't know what the right procedure is.
I would just restore the old one, compare carefully with the new one to see if there really is something to add, then do the trick with yast.
But listen first to what Andrei suggests, he is the expert ;-)
I also use diff to compare changes, it's maybe a little more work than meld, but the idea is the same.
Yes, just more visual :-)
-- Cheers / Saludos,
Carlos E. R. (from 42.2 x86_64 "Malachite" at Telcontar)