Arch Linux

itarill

Member

Registered: 2020-06-03

Posts: 59

[Solved] btrfs snapshot restore -> emergency mode

I have restored a snapshot (for reasons) from this morning via brtfs-assistant. I rebooted immediately and now I have the following:

# systemctl --failed

- boot.mount
- another optional partition mount
- prof-fs-nfsd.mount (dunno, prolly optional)
- var-lib-nfs-rpc_pipefs.mount
- auth-rpcgss-module.service
- ufw.service

My assumption is that if I fix mounts all of these go away. I see nothing special in fstab, nor should it have changed with respect to /boot.

Any ideas?

Thanks.

Edit: double checked my fstab, the UUID in there and the UUID in blkid are identical.

Last edited by itarill (2024-06-24 12:55:41)

astralc

Member

Registered: 2022-09-17

Posts: 100

Re: [Solved] btrfs snapshot restore -> emergency mode

is the kernel version in /boot and the modules in /usr/lib/modules match?

itarill

Member

Registered: 2020-06-03

Posts: 59

Re: [Solved] btrfs snapshot restore -> emergency mode

I can't seem to be able to mount /boot manually (unknown filesystem type 'vfat', huh?). But there was a small update - I want to say yesterday evening or this morning? [not sure] - which included kernel as well. So it's quite likely the culprit.
I was not aware that this is an issue here, glad to know. How do I get around it?

Thanks.

Last edited by itarill (2024-06-24 10:51:47)

gromit

Package Maintainer (PM)

From: Germany

Registered: 2024-02-10

Posts: 1,111

Website

Re: [Solved] btrfs snapshot restore -> emergency mode

Which kernel do you have booted (uname -a) and whats the version installed via pacman (i.e. "pacman -Q linux")?

itarill

Member

Registered: 2020-06-03

Posts: 59

Re: [Solved] btrfs snapshot restore -> emergency mode

 uname -a 

6.6.35-2-lts

 pacman -Q linux 

6.9.5.arch1-1

gromit

Package Maintainer (PM)

From: Germany

Registered: 2024-02-10

Posts: 1,111

Website

Re: [Solved] btrfs snapshot restore -> emergency mode

Ah if you're using the LTS kernel the output of "pacman -Q linux-lts" is of interest

itarill

Member

Registered: 2020-06-03

Posts: 59

Re: [Solved] btrfs snapshot restore -> emergency mode

6.6.34-1

gromit

Package Maintainer (PM)

From: Germany

Registered: 2024-02-10

Posts: 1,111

Website

Re: [Solved] btrfs snapshot restore -> emergency mode

Yeah so the issue is that you have a mismatch between kernel modules and the booted kernel (as astralc suggested in https://bbs.archlinux.org/viewtopic.php … #p2179739).
Maybe an easy fix would be to update the lts kernel to version 6.6.35-2 so the modules match again and afterwards reboot (with the now hopefully mountable /boot). Since the kernel in question also is the latest I think no cleanup work should be needed afterwards.

# full system update
sudo pacman -Syu 
# or just lts
sudo pacman -U https://archive.archlinux.org/packages/l/linux-lts/linux-lts-6.6.35-2-x86_64.pkg.tar.zst

itarill

Member

Registered: 2020-06-03

Posts: 59

Re: [Solved] btrfs snapshot restore -> emergency mode

Many-many thanks for all the help. This was indeed the issue.

To anyone who'd stumble upon this issue and find this thread: instead of jumping through hoops (curl, chroot etc), I just reinstalled the old kernel from the pacman cache:

pacman -S /var/cache/pacman/pkg/linux-lts-6.6.35-2-x86_64.pkg.tar.zst

Last edited by itarill (2024-06-24 12:56:08)