LazyUnmount in .mount units prevents root fs to umount cleanly

[Cedric Rivard]

Dear Maintainer,

On my debian box, with the default snap .mount units settings, the root FS can't be unmounted during system shutdown or reboot which leads to a long-lasting raid resync operation during the following boot.

This behavior originates from this commit:
https://github.com/snapcore/snapd/commit/5f16e6b0738410d07995b85bc516d9bbb50263c8

LazyUnmount is the root cause of the problem.

Solution:
# grep -r LazyUnmount -l /etc/systemd/ |xargs -n1 sed -e '/LazyUnmount/d' -i
# systemctl daemon-reload

-- System Information:
Debian Release: bullseye/sid
  APT prefers testing
  APT policy: (900, 'testing'), (180, 'unstable'), (170, 'experimental'), (50, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 5.10.2 (SMP w/8 CPU threads; PREEMPT)
Kernel taint flags: TAINT_USER, TAINT_UNSIGNED_MODULE
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages snapd depends on:
ii adduser 3.118
ii apparmor 2.13.5-1+b2
ii ca-certificates 20200601
ii gnupg 2.2.20-1
ii gnupg1 1.4.23-1+b1
ii libapparmor1 2.13.5-1+b2
ii libc6 2.31-5
ii libcap2 1:2.44-1
ii libseccomp2 2.5.1-1
ii libudev1 247.1-3+deb11u1
ii openssh-client 1:8.4p1-3
ii squashfs-tools 1:4.4-2
ii systemd 247.1-3+deb11u1
ii udev 247.1-3+deb11u1

Versions of packages snapd recommends:
ii gnupg 2.2.20-1

Versions of packages snapd suggests:
ii kdialog 4:20.08.2-1
ii zenity 3.32.0-6

[Maciej Borzecki (maciek-borzecki)]

Can you attach the bits of the journal that cover system shutdown and indicate which mounts points are busy?

[Launchpad Janitor (janitor)]

[Expired for Snappy because there has been no activity for 60 days.]