fallocate with FALLOC_FL_ZERO_RANGE produces zero-size files on zfs

[Vasya Pupkin]

This is a duplicate of https://bugs.launchpad.net/ubuntu/+source/mysql-8.0/+bug/1969247 because the bug is critical and still not fixed in Ubuntu 20.04.

Problem: fallocate() called with FALLOC_FL_ZERO_RANGE flag must return error on ZFS, but in Ubuntu 20.04 it doesn't return error and just creates zero-sized files.

This causes hard to recover data corruption with MySQL server 8.0.30 (because it started using fallocate() for redo files). More info here: https://bugs.mysql.com/bug.php?id=108012

Also, I cannot set affected package name as "zfsutils-linux" for some reason, but the problem is in zfsutils-linux, not zfs-linux (such package doesn't even exist in Ubuntu 20.04).

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: zfsutils-linux 0.8.3-1ubuntu12.14
ProcVersionSignature: Ubuntu 5.15.0-41.44~20.04.1-generic 5.15.39
Uname: Linux 5.15.0-41-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl icp
ApportVersion: 2.20.11-0ubuntu27.24
Architecture: amd64
CasperMD5CheckMismatches: ./boot/grub/efi.img
CasperMD5CheckResult: fail
Date: Fri Jul 29 21:51:34 2022
InstallationDate: Installed on 2021-01-21 (554 days ago)
InstallationMedia: Ubuntu-Server 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
ProcEnviron:
 SHELL=/bin/bash
 LANG=C.UTF-8
 TERM=screen.xterm-256color
 PATH=(custom, no user)
SourcePackage: zfs-linux
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Rich (rincebrain)]

The source package which produces the binary package zfsutils-linux is called zfs-linux.

https://github.com/openzfs/zfs/pull/13338 is what you'd like to cherrypick to fix this.