zfs not supported as upperdir or workdir for overlay mount

[Scott Moser]

zfs cannot be used as a filesystem for an overlay mount's 'upperdir' or 'workdir' arguement.

If you have zfs root, or are inside an lxd that uses zfs then you'll not be able to use overlay mounts without working around this bug.

It can be worked around by using a tmpfs.

$ ./test-overlay
container=lxc
$ lsb_release -sc
focal
$ uname -r
5.4.0-25-generic
$ id
uid=0(root) gid=0(root) groups=0(root)
$ df --print-type /tmp/test-dir/mp
Filesystem Type 1K-blocks Used Available Use% Mounted on
default/containers/f2 zfs 14655872 523648 14132224 4% /
$ mount -t tmpfs tmpfs /tmp/test-dir/up
$ mount -t overlay -o lowerdir=/etc,upperdir=/tmp/test-dir/up,workdir=/tmp/test-dir/wk overlay /tmp/test-dir/mp
mount: /tmp/test-dir/mp: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error.

[ 1820.651111] overlayfs: filesystem on '/tmp/test-dir/wk' not supported as upperdir
FAIL

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: linux-image-5.4.0-25-generic 5.4.0-25.29
ProcVersionSignature: Ubuntu 5.4.0-25.29-generic 5.4.30
Uname: Linux 5.4.0-25-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: smoser 6538 F.... pulseaudio
 /dev/snd/controlC2: smoser 6538 F.... pulseaudio
 /dev/snd/controlC1: smoser 6538 F.... pulseaudio
CasperMD5CheckResult: skip
CurrentDesktop: ubuntu:GNOME
Date: Mon Apr 20 13:14:37 2020
InstallationDate: Installed on 2020-01-15 (95 days ago)
InstallationMedia: Ubuntu 18.04.3 LTS "Bionic Beaver" - Release amd64 (20190805)
MachineType: LENOVO 20KGS3Y900
ProcEnviron:
 TERM=xterm-256color
 PATH=(custom, no user)
 XDG_RUNTIME_DIR=<set>
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcFB: 0 i915drmfb
ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-5.4.0-25-generic root=UUID=55cf8bc7-4727-47a8-8b30-7ad55bd24635 ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-5.4.0-25-generic N/A
 linux-backports-modules-5.4.0-25-generic N/A
 linux-firmware 1.187
SourcePackage: linux
UpgradeStatus: Upgraded to focal on 2020-04-17 (3 days ago)
dmi.bios.date: 04/20/2019
dmi.bios.vendor: LENOVO
dmi.bios.version: N23ET63W (1.38 )
dmi.board.asset.tag: Not Available
dmi.board.name: 20KGS3Y900
dmi.board.vendor: LENOVO
dmi.board.version: SDK0J40697 WIN
dmi.chassis.asset.tag: No Asset Information
dmi.chassis.type: 10
dmi.chassis.vendor: LENOVO
dmi.chassis.version: None
dmi.modalias: dmi:bvnLENOVO:bvrN23ET63W(1.38):bd04/20/2019:svnLENOVO:pn20KGS3Y900:pvrThinkPadX1Carbon6th:rvnLENOVO:rn20KGS3Y900:rvrSDK0J40697WIN:cvnLENOVO:ct10:cvrNone:
dmi.product.family: ThinkPad X1 Carbon 6th
dmi.product.name: 20KGS3Y900
dmi.product.sku: LENOVO_MT_20KG_BU_Think_FM_ThinkPad X1 Carbon 6th
dmi.product.version: ThinkPad X1 Carbon 6th
dmi.sys.vendor: LENOVO

[Ubuntu Kernel Bot (ubuntu-kernel-bot)]

This change was made by a bot.