[Bug 1844012] Re: grub2 doesn't recognize ext4 with metadata_csum_seed enabled

[Launchpad Bug Tracker]

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

** Changed in: grub2 (Ubuntu)
       Status: New => Confirmed

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Title:
  grub2 doesn't recognize ext4 with metadata_csum_seed enabled

Status in grub2 package in Ubuntu:
  Confirmed
Status in grub2 package in Debian:
  Unknown

Bug description:
  /usr/lib/grub/x86_64-efi/ext2.mod, from:

  grub-efi-amd64-bin:
    Installed: 2.02-2ubuntu8.13
    Candidate: 2.02-2ubuntu8.13

  doesn't recognize an ext4 filesystem with metadata_csum_seed set.

  This is true in command-line grub, not just the update-grub software.
  Attempting

  linux (hdx,gptx)/ etc

  on an ext4 fs with metadata_csum enabled fails; removing the
  metadata_csum_seed option fixes this.

  The failure is "unknown filesystem" for any ext4 fs with
  metadata_csum_seed set. Apparently saving the metadata checksum seed
  in the superblock changes it beyond recognition for grub.

   The message appears to be coming from 
  grub-2.04/grub-core/kern /fs.c:

  grub_fs_t
  grub_fs_probe (grub_device_t device)
  {....
   grub_error (GRUB_ERR_UNKNOWN_FS, N_("unknown filesystem"));
  }
  which appears to probe for filesystems by calling the fs modules to attempt to mount it.

  
  I tried to install latest grub from eaon to see if upstream has fixed this, but it depended on too much other unreleased software such as libc6.

  I pulled the 2.04 source. There is nothing in the Changelog that
  appears to address this.

  
  from `man ext4`:
   metadata_csum_seed
                This feature allows the filesystem to store the metadata checksum seed in the superblock, which allows the administrator to change the UUID of a filesystem using the metadata_csum feature while it is mounted.

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