[Bug 1424123] Re: Need to update for XFS crc=1 (non-default) on-disk format change

[Mathieu Trudel-Lapierre]

Setting to Triaged/Low, since it's not currently a default in any kind
of way. I'll review/test the patches and try to upstream them.

** Bug watch added: Red Hat Bugzilla #1001279
   https://bugzilla.redhat.com/show_bug.cgi?id=1001279

** Also affects: grub2 (Fedora) via
   https://bugzilla.redhat.com/show_bug.cgi?id=1001279
   Importance: Unknown
       Status: Unknown

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

** Changed in: grub2 (Ubuntu)
   Importance: Undecided => Low

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Title:
  Need to update for XFS crc=1 (non-default) on-disk format change

Status in grub2 package in Ubuntu:
  Triaged
Status in grub2 package in Fedora:
  Unknown

Bug description:
  Filing a note here in case I forget later.

  It looks like GRUB (2.02-beta2-15) in 14.10 doesn't support XFS's new
  on-disk metadata format that has CRCs.  (rationale:
  https://www.kernel.org/doc/Documentation/filesystems/xfs-self-
  describing-metadata.txt)

  mkfs.xfs -m crc=1,finobt=1 /dev/sdXY   creates an XFS with the new on-
  disk format.  This is NOT the default, and probably won't be until
  kernel support for it has been in distros for a while.

  redhat bug with some patches from Dec 2014:
  https://bugzilla.redhat.com/show_bug.cgi?id=1001279

  I haven't yet dug up any changelogs about those patches getting merged
  into GRUB's upstream git repo.

  If there's a PPA, or an easy way to build a .deb from git master (or
  some other way I can easily test git master on an Ubuntu system), I'd
  be interested and willing to test this.

  Testing confirms that xfs crc support was the issue.  I made two plain
  non-MD partitions to take that out of the equation.  I formatted one
  with XFS defaults, and the other with XFS crc.  I copied my fresh
  ubuntu install into each one.  I did grub-install /dev/sda while
  chrooted into the non-crc xfs, and grub-install /dev/sdb in the CRC
  one.  Booting from sda worked fine.

  Booting from sdb (I can tell them apart in the bios boot menu easily,
  because they're not the same make), I was dropped into the grub rescue
  shell.  I could use grub's ls to see data on the non-crc partition,
  but not on the crc partition.  So it's clear that GRUB doesn't
  understand the new XFS metadata v5 format.

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