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

[Peter Cordes]

This will get fixed upstream at some point for sure, so having the bug
here is probably only useful as a reminder to check that we have an
updated-enough GRUB before the next release, or next LTS release at
worst.


** Description changed:

  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.
  
- (It's possible I'm mistaken here, and my boot problem was from using RAID10,f2, rather than from XFS with crc=1.  testing now.)
+ 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.

-- 
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/1424123

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

Status in grub2 package in Ubuntu:
  New

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.

To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/grub2/+bug/1424123/+subscriptions