[Bug 1982897] [NEW] Changing ZFS compression to type "zstd" on "bpool" will make system un-bootable and effectively irrecoverable

[Nosehair]

Public bug reported:


   This problem impacts 21.10, 22.04 and basically any other Debian-based distribution with root-on-ZFS capability using grub2 versions up-to and including 2.06.


   Changing ZFS compression to type "zstd" on the filesystem "bpool" will effectively kill the system the next time that Software Updater requests an initramfs rebuild or new kernel install.  The system will no longer boot normal or "recovery" kernels and becomes effectively irrecoverable, as Grub2 does not recognize any filesystem with zstd compressiion (and just changing bpool compression type back to "lz4" will not fix it).

    Any attempt to re-install grub, or check device state using grub-
probe results in an "unknown filesystem" error.

   Checking the upstream code for grub2 shows that the "zstd" library
was added in November of 2018 and support code added for BTRFS at the
same time.  There doesn't appear to have been any equivalent support
code added into the ZFS tree, though.

   As recovery from this problem is beyond the capabilities of most
users (the easiest course of action would probably be a complete re-
install), I'd like to raise a request with the upstream maintainers of
grub2 to add the "zstd" support code into the ZFS tree.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: grub2 (not installed)
ProcVersionSignature: Ubuntu 5.15.0-41.44-generic 5.15.39
Uname: Linux 5.15.0-41-generic x86_64
NonfreeKernelModules: zfs zunicode zcommon znvpair zavl icp
ApportVersion: 2.20.11-0ubuntu82.1
Architecture: amd64
CasperMD5CheckResult: pass
CurrentDesktop: MATE
Date: Wed Jul 27 06:44:41 2022
InstallationDate: Installed on 2022-07-17 (9 days ago)
InstallationMedia: Ubuntu-MATE 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
SourcePackage: grub2
UpgradeStatus: No upgrade log present (probably fresh install)

** Affects: grub2 (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: amd64 apport-bug bpool jammy zfs zstd

-- 
You received this bug notification because you are a member of Ubuntu
Foundations Bugs, which is subscribed to grub2 in Ubuntu.
https://bugs.launchpad.net/bugs/1982897

Title:
  Changing ZFS compression to type "zstd" on "bpool" will make system
  un-bootable and effectively irrecoverable

Status in grub2 package in Ubuntu:
  New

Bug description:
  
     This problem impacts 21.10, 22.04 and basically any other Debian-based distribution with root-on-ZFS capability using grub2 versions up-to and including 2.06.

  
     Changing ZFS compression to type "zstd" on the filesystem "bpool" will effectively kill the system the next time that Software Updater requests an initramfs rebuild or new kernel install.  The system will no longer boot normal or "recovery" kernels and becomes effectively irrecoverable, as Grub2 does not recognize any filesystem with zstd compressiion (and just changing bpool compression type back to "lz4" will not fix it).

      Any attempt to re-install grub, or check device state using grub-
  probe results in an "unknown filesystem" error.

     Checking the upstream code for grub2 shows that the "zstd" library
  was added in November of 2018 and support code added for BTRFS at the
  same time.  There doesn't appear to have been any equivalent support
  code added into the ZFS tree, though.

     As recovery from this problem is beyond the capabilities of most
  users (the easiest course of action would probably be a complete re-
  install), I'd like to raise a request with the upstream maintainers of
  grub2 to add the "zstd" support code into the ZFS tree.

  ProblemType: Bug
  DistroRelease: Ubuntu 22.04
  Package: grub2 (not installed)
  ProcVersionSignature: Ubuntu 5.15.0-41.44-generic 5.15.39
  Uname: Linux 5.15.0-41-generic x86_64
  NonfreeKernelModules: zfs zunicode zcommon znvpair zavl icp
  ApportVersion: 2.20.11-0ubuntu82.1
  Architecture: amd64
  CasperMD5CheckResult: pass
  CurrentDesktop: MATE
  Date: Wed Jul 27 06:44:41 2022
  InstallationDate: Installed on 2022-07-17 (9 days ago)
  InstallationMedia: Ubuntu-MATE 22.04 LTS "Jammy Jellyfish" - Release amd64 (20220419)
  SourcePackage: grub2
  UpgradeStatus: No upgrade log present (probably fresh install)

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1982897/+subscriptions