What were you trying to do that didn't work?

Installations of RHEL-10 on available ppc64le machines with Petitboot fail to boot. Further investigations have shown that this is caused by a non-recent version of kernel in the firmware, lacking support of the large extents count feature in XFS (nrext64=1) that is used by default in RHEL-10, so Petitboot is not able to access /boot partition.

This ticket may not necessarily be a bug, but is rather intended as a heads-up and a place for potential discussion whether this can negatively impact some customer scenarios (ATM I'm not aware of any specific related HW requirements for RHEL-10). If we want to have this feature enabled by default (also for /boot), firmware with a recent enough version of kernel (if I'm not mistaken, 5.19 for experimental support or 6.5 for regular support) would be required and this fact will need to be properly documented.

Here's an excerpt from firmware's dmesg output (from Petitboot shell) on an affected machine:

# dmesg | tail 
[   24.750384] XFS (dm-5): Superblock has unknown incompatible features (0x28) enabled.
[   24.750386] XFS (dm-5): Filesystem cannot be safely mounted by this kernel.
[   24.760861] XFS (dm-5): Superblock has unknown read-only compatible features (0x8) enabled.
[   24.760864] XFS (dm-5): Superblock has unknown incompatible features (0x28) enabled.
[   24.760865] XFS (dm-5): Filesystem cannot be safely mounted by this kernel.
[   24.984731] XFS (sdb1): Superblock has unknown read-only compatible features (0x8) enabled.
[   24.984733] XFS (sdb1): Superblock has unknown incompatible features (0x28) enabled.
[   24.984734] XFS (sdb1): Filesystem cannot be safely mounted by this kernel.
[   25.032483] EXT4-fs (dm-5): mounted filesystem with ordered data mode. Opts: (null)
[   25.088131] EXT4-fs (dm-8): mounted filesystem with ordered data mode. Opts: (null) 

Please provide the package NVR for which bug is seen:

RHEL-10.0-20240530.64 / xfsprogs-6.5.0-3.el10.ppc64le; firmware with Petitboot v1.11 / Linux skiroot 5.3.7-openpower1.

How reproducible:

Always.

Steps to reproduce

1. Install RHEL-10 on a ppc64le Petitboot machine with firmware using kernel < 5.19 and reboot to the installed system.

Expected results

Installed system boots fine.

Actual results

Installed system doesn't boot, because /boot is formatted using XFS with nrext64=1 feature.

Additional notes

This issue can be worked around either by instructing Anaconda to use ext4 filesystem for /boot partition, or by disabling the nrext64 feature in kickstart by supplying --mkfsoptions="-i nrext64=0" }}option to the relevant {{part command.