URL:
<https://savannah.gnu.org/bugs/?59614>
Summary: grub-mkconfig on ZFS root result has invalid
root=ZFS= value
Project: GNU GRUB
Submitted by: csleuth7
Submitted on: Thu 03 Dec 2020 08:55:13 PM UTC
Category: Configuration
Severity: Major
Priority: 5 - Normal
Item Group: Software Error
Status: None
Privacy: Public
Assigned to: None
Originator Name: Todd
Originator Email: c...@compusleuth.com
Open/Closed: Open
Release:
Release: other
Discussion Lock: Any
Reproducibility: Every Time
Planned Release: None
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Details:
This problem was identified using Ubuntu 20.04.1 and selecting the ZFS root
option during installation. The grub version is 2.04-1ubuntu26.7
Installation will boot, but after any install or upgrade that requires
touching the grub configuration the resulting grub.cfg has an invalid
root=ZFS=/ROOT/ubuntu_xxxxxx value which is missing the zpool name, the
correct value should look like this:
root=ZFS=rpool/ROOT/ubuntu_xxxxxx
The root cause seems to be in these two files:
/etc/grub.d/10_linux (line 137)
/etc/grub.d/20_linux_xen (line 88)
Which contain a line that sets the value of ${rpool} like this:
rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label 2>/dev/null ||
true`
This is setting ${rpool} to NULL since the grub-probe fails:
root@stream:/etc/grub.d# /usr/sbin/grub-probe --device /dev/nvme0n1p4
--target=fs_label
/usr/sbin/grub-probe: error: unknown filesystem.
Since this rpool= line should only be run when the root filesystem is ZFS, I
would expect this will always fail on every system with a ZFS root.
This is my hack test fix, (applied to both files):
------------------------------
rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label
2>/dev/null || true`
if [ "${rpool}" = "" ]; then
rpool=`/usr/sbin/zfs list | awk '{if( $5 == "/" ) { print $1; }}' |
sed "s:/.*::" | head -1`
fi
bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
------------------------------
This test resolved the problem and worked on my three test systems:
Ubuntu 20.04 ZFS root
Ubuntu 20.04 ZFS root with Xen installed
Ubuntu 20.04 xfs root
Although this worked, I expect a better fix would just change the rpool=``
line with a command that works. My example fix assumed Ubuntu 20.04 was
installed with ZFS, and I did not consider any other configurations. I don't
expect details about my hardware would affect this issue, but two used
ASRock+AMD and the 3rd was an old Lenovo laptop.
_______________________________________________________
File Attachments:
-------------------------------------------------------
Date: Thu 03 Dec 2020 08:55:13 PM UTC Name: grub-mkconfig.log Size: 17KiB
By: csleuth7
Example grub-mkconfig log
<http://savannah.gnu.org/bugs/download.php?file_id=50393>
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