ubuntu fails to boot into/rollback to any previous snapshot

[Arvydas Ramanauskas]

This is happening on fresh Ubuntu 20.10 install with just nvidia drivers and a few cmd utilities installed. When I try to rollback to any previous snapshot from grub menu, Ubuntu never rolls back to that snapshot.

I choose a previous snapshot form grub menu, history submenu (doesn't matter if system only or system with user data). OS starts to boot, low res plymouth shows up but the OS never finishes booting. When I press ESC to see whats going on, the boot process is stuck at "Reached target sound card". If I press CTRL+ALT+DEL computer restarts and OS boots up normally into the last state it was in. That is the filesystem didn't rollback. When I inspect the zfs datasets with "zfs list" and "zsysctl show" there is a new dataset in rpool "rpool/ROOT/ubuntu_". A dataset without a suffix. Unfortunately I couldn't find anything in journalctl and I don't know where to look for more logs.

Now, if I choose to rollback to a snapshot in recovery mode the OS boots up but the file system is in some broken state. For example missing packages, snaps not working. Zsysctl shows that current dataset is a dataset without suffix (rpool/ROOT/ubuntu_). I guess the filesystem is in broken state because the other datasets under ubuntu_xxxxxx didn't get mounted or something.

This time I found something in journalctl logs.
okt 26 15:17:16 evilroot ERROR: zfs-mount-generator failed and you requested a revert:
okt 26 15:17:16 evilroot unknown: level=error msg="couldn't ensure boot: Mounted clone bootFS dataset created by initramfs doesn't have a valid _suffix (at least .*_<onechar>): \"rpool/ROOT/ubuntu_\""
okt 26 15:17:16 evilroot unknown: You can reboot on current master dataset to fix the issue
okt 26 15:17:16 evilroot systemd[783]: /usr/lib/systemd/system-generators/zfs-mount-generator failed with exit status 1.

If I reboot, the OS boots up normally again into the last state it was in. So no change.

This is my first attempt at reporting a bug so I apologize if I'm not doing it right. If someone needs more information just tell me where to look for it and I will gladly provide it.

ProblemType: Bug
DistroRelease: Ubuntu 20.10
Package: zsys 0.5.2
ProcVersionSignature: Ubuntu 5.8.0-25.26-generic 5.8.14
Uname: Linux 5.8.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu50
Architecture: amd64
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Oct 26 16:39:19 2020
InstallationDate: Installed on 2020-10-25 (0 days ago)
InstallationMedia: Ubuntu 20.10 "Groovy Gorilla" - Release amd64 (20201022)
ProcKernelCmdLine: BOOT_IMAGE=/BOOT/ubuntu_qcdycn@/vmlinuz-5.8.0-25-generic root=ZFS=rpool/ROOT/ubuntu_qcdycn ro quiet splash vt.handoff=1
RelatedPackageVersions:
 zfs-initramfs 0.8.4-1ubuntu11
 zfsutils-linux 0.8.4-1ubuntu11
SourcePackage: zsys
SystemdFailedUnits:
 Error: command ['systemctl', 'status', '--full', '●'] failed with exit code 4: Invalid unit name "●" escaped as "\xe2\x97\x8f" (maybe you should use systemd-escape?).
 Unit \xe2\x97\x8f.service could not be found.
UpgradeStatus: No upgrade log present (probably fresh install)
ZFSImportedPools:
 NAME SIZE ALLOC FREE CKPOINT EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
 bpool 1,88G 197M 1,68G - - 0% 10% 1.00x ONLINE -
 rpool 920G 89,7G 830G - - 0% 9% 1.00x ONLINE -
ZFSListcache-bpool:
 bpool /boot off on on off on off on off - none - - - - - - - -
 bpool/BOOT none off on on off on off on off - none - - - - - - - -
 bpool/BOOT/ubuntu_qcdycn /boot on on on off on off on off - none - - - - - - - -
ZSYSJournal:
 -- Logs begin at Sun 2020-10-25 19:43:07 CET, end at Mon 2020-10-26 16:39:05 CET. --
 [ 14.707892] evilroot zsysctl[2818]: ZSys is adding automatic system snapshot to GRUB menu
 [ 84.018383] evilroot zsysd[1809]: aitvaras

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.