package zfsutils-linux 0.8.3-1ubuntu12.4 failed to install/upgrade: installed zfsutils-linux package post-installation script subprocess returned error exit status 1

[Erik Elfgren]

When I try to update zfsutils-linux, the upgrade process tries to mount all zfs file systems but since my root / is on zfs it fails with:
nov 22 08:21:28 Home systemd[1]: Starting Mount ZFS filesystems...
nov 22 08:21:28 Home zfs[286979]: cannot mount '/': directory is not empty
nov 22 08:21:28 Home systemd[1]: zfs-mount.service: Main process exited, code=exited, status=1/FAILURE
nov 22 08:21:28 Home systemd[1]: zfs-mount.service: Failed with result 'exit-code'.
nov 22 08:21:28 Home systemd[1]: Failed to start Mount ZFS filesystems.

As a consequence, the upgrade process fails.

ProblemType: Package
DistroRelease: Ubuntu 20.04
Package: zfsutils-linux 0.8.3-1ubuntu12.4
ProcVersionSignature: Ubuntu 5.4.0-40.44-generic 5.4.44
Uname: Linux 5.4.0-40-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair nvidia_modeset nvidia
ApportVersion: 2.20.11-0ubuntu27.12
AptOrdering:
 linux-headers-5.4.0-52-generic:amd64: Remove
 linux-headers-5.4.0-52:amd64: Remove
 NULL: ConfigurePending
Architecture: amd64
CasperMD5CheckResult: skip
Date: Sun Nov 22 06:41:54 2020
ErrorMessage: installed zfsutils-linux package post-installation script subprocess returned error exit status 1
InstallationDate: Installed on 2020-07-08 (136 days ago)
InstallationMedia: Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200423)
Python3Details: /usr/bin/python3.8, Python 3.8.5, python3-minimal, 3.8.2-0ubuntu2
PythonDetails: /usr/bin/python2.7, Python 2.7.18, python-is-python2, 2.7.17-4
RelatedPackageVersions:
 dpkg 1.19.7ubuntu3
 apt 2.0.2ubuntu0.1
SourcePackage: zfs-linux
Title: package zfsutils-linux 0.8.3-1ubuntu12.4 failed to install/upgrade: installed zfsutils-linux package post-installation script subprocess returned error exit status 1
UpgradeStatus: No upgrade log present (probably fresh install)
mtime.conffile..etc.default.zfs: 2020-08-05T10:29:12.101838

[Colin Ian King (colin-king)]

I wonder if this has to do with the fact that the defaults in /etc/default/zfs have been modified:

# Wait for this many seconds in the initrd pre_mountroot?
# This delays startup and should be '0' on most systems.
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_INITRD_PRE_MOUNTROOT_SLEEP='0'

# Wait for this many seconds in the initrd mountroot?
# This delays startup and should be '0' on most systems. This might help on
# systems which have their ZFS root on a USB disk that takes just a little
# longer to be available
# Only applicable for Debian GNU/Linux {dkms,initramfs}.
ZFS_INITRD_POST_MODPROBE_SLEEP='0'

# List of additional datasets to mount after the root dataset is mounted?
#
# The init script will use the mountpoint specified in the 'mountpoint'
# property value in the dataset to determine where it should be mounted.
#
# This is a space separated list, and will be mounted in the order specified,
# so if one filesystem depends on a previous mountpoint, make sure to put
# them in the right order.
#
# It is not necessary to add filesystems below the root fs here. It is
# taken care of by the initrd script automatically. These are only for
# additional filesystems needed. Such as /opt, /usr/local which is not
# located under the root fs.
# Example: If root FS is 'rpool/ROOT/rootfs', this would make sense.
#ZFS_INITRD_ADDITIONAL_DATASETS="rpool/ROOT/usr rpool/ROOT/var"
ZFS_INITRD_ADDITIONAL_DATASETS="x data x/tmp data/tmp x/livebackup"

[Colin Ian King (colin-king)]

zfs mount on / is failing because / is not empty:

● zfs-mount.service - Mount ZFS filesystems
     Loaded: loaded (/lib/systemd/system/zfs-mount.service; enabled; vendor preset: enabled)
     Active: failed (Result: exit-code) since Sun 2020-11-22 06:41:54 CET; 3ms ago
       Docs: man:zfs(8)
    Process: 4123780 ExecStart=/sbin/zfs mount -a (code=exited, status=1/FAILURE)
   Main PID: 4123780 (code=exited, status=1/FAILURE)

nov 22 06:41:54 Home systemd[1]: Starting Mount ZFS filesystems...
nov 22 06:41:54 Home zfs[4123780]: cannot mount '/': directory is not empty
nov 22 06:41:54 Home systemd[1]: zfs-mount.service: Main process exited, code=exited, status=1/FAILURE
nov 22 06:41:54 Home systemd[1]: zfs-mount.service: Failed with result 'exit-code'.
nov 22 06:41:54 Home systemd[1]: Failed to start Mount ZFS filesystems.
dpkg: error processing package zfsutils-linux (--configure):
 installed zfsutils-linux package post-installation script subprocess returned error exit status 1

This suggests a ZFS on / was installed. Do you mind informing me how the install was performed?

[Launchpad Janitor (janitor)]

[Expired for zfs-linux (Ubuntu) because there has been no activity for 60 days.]