Yocto Custom Layer run Tune2fs on do_rootfs after mkfs.ext4

Question

I'm using Yocto on Ubuntu 18.04 with the Warrior Branch of Meta-Tegra in order to try to integrate the RAUC Open Source project for Linux Firmware Updates.

I've learned that U-Boot has issues writing to EXT4 partitions ( to update the U-Boot Env ) if the EXT4 filesystem it is writing to has the metadata_csum attribute. Linux cannot mount the Root Filesystem if that attribute is enabled and U-Boot writes at all to it.

Here are some posts on that:

• https://patchwork.ozlabs.org/patch/818337/

• http://u-boot.10912.n7.nabble.com/PATCH-1-1-fs-ext4-do-not-write-on-filesystem-with-metadata-csum-feature-td362715.html

I proved that this is the case by mounting the resulting SDCARD image from Yocto on Ubuntu and running the following command to disable metadata_csum:

sudo tune2fs -O ^metadata_csum /dev/sdb1
tune2fs 1.44.1 (24-Mar-2018)
Disabling checksums could take some time.
Proceed anyway (or wait 5 seconds to proceed) ? (y,N) y

After running that command - U-Boot can read/write at will from U-Boot space and Linux can mount the Root File System.

I am trying to figure out how to disable the checksums with Tune2fs on Ubuntu at image creation time with Yocto. Where/How can I add this so that the image has checksums disabled at image creation time from Yocto? Thanks.

Answer 1

I briefly looked over meta-tegra and I think it uses the ext4 root filesystem image created through image_class.bcclass. You can add parameters to the mkfs.ext4 thorugh EXTRA_IMAGECMD. It should be possible to just create the filesystem with metadata_csum disabled, instead of turning it off later.

Try

EXTRA_IMAGECMD_append = " -O ^metadata_csum"

in your local.conf