[Pkg-zfsonlinux-devel] Bug#1100086: zvol sync/flush regression in 2.2.7+

[Fabian Grünbichler]

Subject: zvol sync/flush regression in 2.2.7+
Package: zfs-dkms
X-Debbugs-Cc: f.gruenbichler at proxmox.com
Version: 2.2.7-1
Severity: grave
Forwarded: https://github.com/openzfs/zfs/pull/17131
Tags: upstream patch

hi!

zfs 2.2.7 and later do not honor all kinds of sync writes/flush requests
properly when issued on zvols. notably, using a zvol as backing device
for a Qemu virtual block device is affected, and ZFS treats all sync
writes issued by applications in the VM as async. this can lead to
inconsistencies or dataloss.

I bisected and found the upstream commit introducing the regression, and
proposed a fix upstream (see linked PR, which also contains a reproducer).

the packages in trixie and bookworm-backports should probably both be
updated, the fix is rather small and targeted ;)

thanks for your consideration!
Fabian

-- System Information:
Debian Release: trixie/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: arm64

Kernel: Linux 6.12.17-amd64 (SMP w/8 CPU threads; PREEMPT)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8), LANGUAGE not set
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages zfs-dkms depends on:
ii  debconf [debconf-2.0]  1.5.91
ii  dkms                   3.1.5-1
ii  file                   1:5.45-3+b1
ii  libc6-dev [libc-dev]   2.41-4
ii  libpython3-stdlib      3.13.2-2
ii  lsb-release            12.1-1

Versions of packages zfs-dkms recommends:
ii  linux-libc-dev  6.12.17-1
ii  zfs-zed         2.3.0-2
ii  zfsutils-linux  2.3.0-2

Versions of packages zfs-dkms suggests:
ii  debhelper  13.24.1

-- debconf information excluded
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