Unable to force fsck on reboot

[dmtucker]

I can't figure out how to run fsck on /. I've tried:

• fsck.mode=force on the kernel command line (i.e. pressing e before clear boots)
• sudo tune2fs -C 70 -c 1 /dev/sda3 && reboot
• sudo tune2fs -i 1m /dev/sda3 && reboot (the last run was over a year ago according to tune2fs)

I'm on 32510.

[ahkok]

Thanks for reporting - this is really strange...

[thiagomacieira]

fsck should be triggered by systemd and I've never seen it do that.

If you need a one-off, I suggest booting the system in emergency mode. You'll get to the shell before systemd remounts your root read-write. I don't think periodic fsck is supported any more.

[dmtucker]

Ah, GTK... I was able to work around using the live desktop image on a USB, FWIW.

One thing I didn't try was creating an /etc/fstab (does fsck require that?)... I don't have one, but I've read there are metrics in there that fsck uses to tell which partitions to check.

[thiagomacieira]

One of the fields in fstab is the scan frequency. Without an fstab, you get autogenerated ones from systemd, which will probably have frequency 0. With an fstab, it'll parse and generate from your choices.

[ahkok]

@thiagomacieira is correct, and man systemd.fsck confirms this in part - you need to create /etc/fstab entries with the proper frequency set to a non-zero value in order for the fsck.mode thing to work.

[dmtucker]

Interesting, looks like it's actually the order to check in 🤔
I suppose that's how tune2fs fits into this: Systemd decides when to check according to tune2fs, and it checks in the order specified in /etc/fstab?

[random-user-00]

There is a systemd unit for it: systemd-fsck-root.service
But the question is, how to enable it?

$ sudo systemctl cat systemd-fsck-root.service 
#  SPDX-License-Identifier: LGPL-2.1+
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=File System Check on Root Device
Documentation=man:systemd-fsck-root.service(8)
DefaultDependencies=no
Conflicts=shutdown.target
Before=local-fs.target shutdown.target
ConditionPathIsReadWrite=!/

[Service]
Type=oneshot
RemainAfterExit=yes
ExecStart=/usr/lib/systemd/systemd-fsck
TimeoutSec=0

I believe it is supposed to be a part of correct target, but not able to figure out which.
I tried to enable it at local-fs-pre.target and basic.target, but fsck didn't run because of condition ConditionPathIsReadWrite=!/. Then I commented that condition and fsck did run during boot but complained about systemd-fsck[344]: Root directory is writable, skipping check.

[MikhailRokhin]

Confirm at

Linux 5.10.113-64.lts2020 #1 SMP Wed Apr 27 06:05:02 PDT 2022 x86_64 GNU/Linux

$ sudo swupd info --verbose

Distribution: Clear Linux OS
Installed version: 36640 (format 30)

[bernimoses]

For me changing the correct kernel line in /boot/syslinux.cfg from ... rw to ... ro fsck.mode=force (to read-only mount first and do the fsck) and adding the option rw to the root partition (to read-write mount after the check is done) in /etc/fstab did the trick. Not sure why syslinux is used.