[Pkg-zfsonlinux-devel] Bug#962424: zfsutils-linux: systemd zfs-mount-generator breaks boot if multiple datasets have the same mountpoint

[wxcafe]

Package: zfsutils-linux
Version: 0.8.4-1~bpo10+1
Severity: grave
Tags: upstream
Justification: renders package unusable

Hey

The systemd zfs-mount-generator script
(/lib/systemd/system-generators/zfs-mount-generator) can break system
boot if there are multiple datasets with the same mountpoint, because it
ignores the zfs property canmount=noauto.

I store backups on my system and after upgrading the system wouldn't
boot anymore because while my backups are canmount=noauto, the generator
was trying to mount multiple datasets to the same mountpoints (/, /usr/,
...) which obviously breaks... everything.

I'd say that's less than ideal. ZoL's integration with systemd has
always been subpar (until 0.8.4 zfs-import-cache was broken because it
looked at /usr/local/etc/zfs/zpool.cache instead of
/etc/zfs/zpool.cache, for example), but breaking boot in a patch release
is really not good


-- System Information:
Debian Release: 10.4
  APT prefers stable
  APT policy: (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 5.5.0-0.bpo.2-amd64 (SMP w/8 CPU cores)
Kernel taint flags: TAINT_PROPRIETARY_MODULE, TAINT_OOT_MODULE, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8), LANGUAGE=en_US.UTF-8 (charmap=UTF-8) (ignored: LC_ALL set to en_US.UTF-8)
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages zfsutils-linux depends on:
ii  libblkid1        2.33.1-0.1
ii  libc6            2.28-10
ii  libnvpair1linux  0.8.4-1~bpo10+1
ii  libudev1         241-7~deb10u4
ii  libuuid1         2.33.1-0.1
ii  libuutil1linux   0.8.4-1~bpo10+1
ii  libzfs2linux     0.8.4-1~bpo10+1
ii  libzpool2linux   0.8.4-1~bpo10+1
ii  python3          3.7.3-1
ii  zlib1g           1:1.2.11.dfsg-1

Versions of packages zfsutils-linux recommends:
ii  lsb-base                10.2019051400
ii  zfs-dkms [zfs-modules]  0.8.4-1~bpo10+1
ii  zfs-zed                 0.8.4-1~bpo10+1

Versions of packages zfsutils-linux suggests:
pn  nfs-kernel-server  <none>
pn  samba-common-bin   <none>
ii  zfs-initramfs      0.8.4-1~bpo10+1

-- Configuration Files:
/etc/cron.d/zfsutils-linux [Errno 2] No such file or directory: '/etc/cron.d/zfsutils-linux'
/etc/sudoers.d/zfs [Errno 13] Permission denied: '/etc/sudoers.d/zfs'

-- no debconf information