[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
the method above doesn't fully work, since even though grub doesn't pass the
subvol= option to the kernel, it still tries to find kernel at full path,
including the subvolume name.
e.g. in /boot/grub/grub.cfg there are lines like:
linux /@/boot/vmlinuz-5.13.0-20-generic
to make it work as easy as on OpenSuse i have made separate subvolume
for /boot
1.
in /etc/grub.d/10_linux
i have removed (commented out) the lines:
# case x"$GRUB_FS" in
# xbtrfs)
# rootsubvol="`make_system_path_relative_to_its_root /`"
# rootsubvol="${rootsubvol#/}"
# if [ "x${rootsubvol}" != x ]; then
# GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol}
${GRUB_CMDLINE_LINUX}"
# fi;;
# xzfs)
# # We have a more specialized ZFS handler, with multiple system in
10_linux_zfs.
# if [ -e "`dirname $(readlink -f $0)`/10_linux_zfs" ]; then
# exit 0
# fi
# rpool=`${grub_probe} --device ${GRUB_DEVICE} --target=fs_label
2>/dev/null || true`
# bootfs="`make_system_path_relative_to_its_root / | sed -e "s,@$,,"`"
# LINUX_ROOT_DEVICE="ZFS=${rpool}${bootfs%/}"
# ;;
# esac
Though i could have commented out only the btrfs related path, but i
don't use zfs anyway
2.
Then mounted the btrfs root subvolume (subvolid=5 option) sudo mount -L sys -o
subvolid=5 /mnt
and created @boot subvolume there, and copied (cp -a) the boot directory from
my previous boot.
3.
created fstab record for the new boot:
LABEL=sys /boot btrfs defaults,subvol=@boot 0 2
and mounted it
mount -a
mount /boot/efi
4.
update-grub
Now works fine even on top of luks.
I have also created separate subvolume for /var/log but this is optional.
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snapper rollback does not work on ubuntu for btrfs
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[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
** Tags removed: artful -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
I've experienced this as well, thanks to @jseiters I was able to perform a rollback. But is definitely not a nice experience when urgently needing the rollback for the first time! Hope It's fixed. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
Status changed to 'Confirmed' because the bug affects multiple users. ** Changed in: snapper (Ubuntu) Status: New => Confirmed -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
I think I have found a way but it is more of a hack. When I remove:
rootflags=subvol=${rootsubvol}
from the line GRUB_CMDLINE_LINUX="rootflags=subvol=${rootsubvol}
${GRUB_CMDLINE_LINUX}" in the file /etc/grub.d/10_linux I can boot from the rw
snapshot snapper makes when I issue the command:
sudo snapper rollback 38
You will have to do an update-grub before the snapper rollback command to write
the new cfg file.
This method will most likely fail if an update replaces the 10_linux file and I
don't know how safe it is considering it is not officially supported.
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snapper rollback does not work on ubuntu for btrfs
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[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
Interesting... I still can't easily test right now, but if you try to mount the device manually, possibly from an live disk (`mount /dev/sdXX /path`), does the right subvol get mounted? -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
I tested your workaround with Ubuntu 16.04 with no luck. 1- remove subvol=@ 2- also add the same root ID with UUID=ce4d5d13-5ec7-4b2f-b519-569e04729d1e /.snapshots btrfs subvol=@/.snapshots 0 1 as OpenSuSE fstab. 3- btrfs subvolume set-default (SNAP NUMBER) / any help? I need to rollback as easy to do in OpenSuSE. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
So I think I know why this doesn't work under Ubuntu and it's related to the mount options Ubuntu sets by default for btrfs for a new installation. By default, Ubuntu installs systems with btrfs into a subvolume called @ and the home directory into a subvolume called @home. It then proceeds to add the mount options of subvol=@ to /etc/fstab for the root volume's mount. This is all great until you want to revert via snapper. Before going further, I want to clarify that, afaik, snapshots are just subvolumes for BTRFS. For snapper, the subvolume has a path of /.snapshots//snapshot. Since this is relative to the rootfs mounted, which is @, I believe it's actually @/.snapshots//snapshot. snapper's rollback works by using the default subvolume feature for a filesystem. This means if you mount that file system (mount /dev/sda1), it will mount that subvolume instead of the top-level file system. As an example, when rolling back to @/.snapshots/10/snapshot, snapper creates a read-writable subvolume from snapshot #10 and sets that as the default subvolume for the filesystem instead of the usual /. Its design hopes that on the next boot of the system, it will boot from the newly cloned rw-able snapshot, as opposed to the original subvolume. Note that it does not alter @. However, since ubuntu's fstab entry for the root volume has subvol=@ as the default flag, it will ALWAYS mount subvol=@ as / and never mount the default subvolume as /. As a workaround, you could in theory: 1. Remove the subvol=@ options from /etc/fstab 2. Set the default subvolume for your filesystem to be @ (or whatever snapshot you're using). I haven't tested this yet, but it _should_ fix this problem. Although this may be more preferable to be done by the ubuntu installer by default instead. However, doing that is a major change and might have other implications that I'm not aware of. Additionally, the .snapshots folder under @ is not quite idea for rollbacks from a liveCD... I don't know what the optimal layout would be tho, but having it nested under @ means you can't do something like mv @/.snapshots/.../snapshot @ easily. -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
[Bug 1734496] Re: snapper rollback does not work on ubuntu for btrfs
** Summary changed: - snapper rollback does not work on ubuntu + snapper rollback does not work on ubuntu for btrfs -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1734496 Title: snapper rollback does not work on ubuntu for btrfs To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/snapper/+bug/1734496/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
