Debian Bug report logs - #955413
btrfs-progs: new mount-time checking causes systemd to timeout and boot failure

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Message #5 received at submit@bugs.debian.org (full text, mbox, reply):

From: Graham Cobb <g+debian@cobb.uk.net>

To: Debian Bug Tracking System <submit@bugs.debian.org>

Subject: btrfs-progs: new mount-time checking causes systemd to timeout and boot failure

Date: Tue, 31 Mar 2020 13:20:48 +0100

Package: btrfs-progs
Version: 5.3.1-1
Severity: minor

The new checks at mount time cause mount times for large filesystems to be much
longer. My roughly 10TB filesystem now takes over 90 seconds to mount.

Unfortunately, this is longer than the default systemd mount timer and systemd
assumes the mount has failed (and, in fact, cancels it). If the mount is not
marked with "nofail" this causes boot to fail and to drop into the rescue
console.

This new checking is a good thing, and neither the new checks, nor the systemd
behaviour are bugs, nor are they the responsibility of btrfs-progs.

It is likely that users of large btrfs filesystems will have btrfs-progs
installed. So, I believe it would be extremely useful to add a NEWS item to the
next btrfs-progs package release to warn btrfs users of this change and
recommend that they consider making changes to /etc/fstab for any btrfs
volumes mounted at boot time.

Alternatively, the NEWS item could be included in the kernel release, however
that would target a much larger group of people than just btrfs users.

A release notes entry for bullseye should also be considered.

Suggested NEWS text:

BTRFS filesystems are now checked for tree corruption at mount time.
For filesystems of around 10TB or larger, this is likely to cause the mount
time to exceed the default systemd mount timeout of 90 seconds. If the
filesystem is mounted at boot time, and not marked as "nofail", this will cause
the boot to fail.

The systemd mount timeout can be increased in /etc/fstab by setting the mount
option x-systemd.mount-timeout= with a new timeout value in seconds.
See systemd.mount(5) for full documentation on the systemd mount options
that can be specified in /etc/fstab.



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

Kernel: Linux 5.4.0-4-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_IE.utf8, LC_CTYPE=en_IE.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_IE.utf8), LANGUAGE=en_IE.utf8 (charmap=UTF-8) (ignored: LC_ALL set to en_IE.utf8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages btrfs-progs depends on:
ii  libblkid1    2.34-0.1
ii  libc6        2.29-7
ii  libcom-err2  1.45.4-1
ii  libext2fs2   1.45.4-1
ii  liblzo2-2    2.10-0.1
ii  libuuid1     2.34-0.1
ii  libzstd1     1.4.4+dfsg-1
ii  zlib1g       1:1.2.11.dfsg-1+b1

btrfs-progs recommends no packages.

Versions of packages btrfs-progs suggests:
pn  duperemove  <none>

-- no debconf information

Message #10 received at 955413@bugs.debian.org (full text, mbox, reply):

From: Christoph Anton Mitterer <calestyo@scientia.net>

To: 955413@bugs.debian.org

Subject: Re: btrfs-progs: new mount-time checking causes systemd to timeout and boot failure

Date: Fri, 03 Apr 2020 15:44:48 +0200

We see that, too, at the institute... any larger (few TB) filesystems
in /etc/fstab make systemd cause the system to fail at boot... leaving
it a state with no remote resuce (ssh) being possible.

Since such filesystems would mount just fine... I would rather say that
this functionality is a severe bug.


Cheers,
Chris.

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