One use-case on our side is the generation of SWUpdate image. Our helper class uses do_ext4_image to generate the file-system image we later embed into the .swu file

Hope that helps

Cedric

On Tuesday, February 19, 2019 at 10:25:58 AM UTC+1, Henning Schild wrote:

Hi,

did you do some research on ext4-usage, we might be able to just drop
it and use wic instead. The qemus will have to switch from i.e.
root=/dev/sda to /dev/sda1 ... sounds easy enough. As far as i can tell
they are the only users in Isar. And outside a raw ext4 partition does
not seem to be too useful either, we could always keep it as
"deprecated" if we are afraid of that move.

Henning

On Mon, 18 Feb 2019 14:04:29 +0100
"[ext] claudius....@siemens.com" <claudius....@siemens.com>
wrote:

> From: Claudius Heine <c...@denx.de>
>
> EXT4_IMAGE_FILE does no longer contain the full path to the ext4 image
> in the deploy directory.
>
> Signed-off-by: Claudius Heine <c...@denx.de>
> ---
>  meta-isar/classes/rpi-sdimg.bbclass |  2 +-
>  meta/classes/ext4-img.bbclass       | 31
> +++++++++++------------------ 2 files changed, 13 insertions(+), 20
> deletions(-)
>
> diff --git a/meta-isar/classes/rpi-sdimg.bbclass
> b/meta-isar/classes/rpi-sdimg.bbclass index 91b09cd..4e5d170 100644
> --- a/meta-isar/classes/rpi-sdimg.bbclass
> +++ b/meta-isar/classes/rpi-sdimg.bbclass
> @@ -15,7 +15,7 @@ BOOT_SPACE ?= "40960"
>  IMAGE_ROOTFS_ALIGNMENT = "4096"
>  
>  SDIMG = "${DEPLOY_DIR_IMAGE}/${PN}.rpi-sdimg"
> -SDIMG_ROOTFS = "${EXT4_IMAGE_FILE}"
> +SDIMG_ROOTFS = "${DEPLOY_DIR_IMAGE}/${EXT4_IMAGE_FILE}"
>  
>  do_rpi_sdimg () {
>      # Align partitions
> diff --git a/meta/classes/ext4-img.bbclass
> b/meta/classes/ext4-img.bbclass index 29e5f77..2620de9 100644
> --- a/meta/classes/ext4-img.bbclass
> +++ b/meta/classes/ext4-img.bbclass
> @@ -1,30 +1,23 @@
>  # This software is a part of ISAR.
>  # Copyright (C) 2015-2017 ilbers GmbH
>  
> -EXT4_IMAGE_FILE = "${DEPLOY_DIR_IMAGE}/${IMAGE_FULLNAME}.ext4.img"
> +EXT4_IMAGE_FILE = "${IMAGE_FULLNAME}.ext4.img"
> +
> +IMAGER_INSTALL += "e2fsprogs"
>  
>  do_ext4_image[stamp-extra-info] = "${DISTRO}-${MACHINE}"
>  
>  # Generate ext4 filesystem image
>  do_ext4_image() {
> -    rm -f ${EXT4_IMAGE_FILE}
> -
> -    dd if=/dev/zero of=${EXT4_IMAGE_FILE} bs=1k count=${ROOTFS_SIZE}
> -
> -    sudo mkfs.ext4 -F ${EXT4_IMAGE_FILE}
> -
> -    mkdir -p ${WORKDIR}/mnt
> -    sudo mount -o loop ${EXT4_IMAGE_FILE} ${WORKDIR}/mnt
> -    _do_ext4_image_cleanup() {
> -        ret=$?
> -        sudo umount ${WORKDIR}/mnt 2>/dev/null || true
> -        sudo rmdir ${WORKDIR}/mnt 2>/dev/null || true
> -        (exit $ret) || bb_exit_handler
> -    }
> -    trap '_do_ext4_image_cleanup' EXIT
> -    sudo cp -r ${IMAGE_ROOTFS}/* ${WORKDIR}/mnt
> -    _do_ext4_image_cleanup
> +    rm -f '${DEPLOY_DIR_IMAGE}/${EXT4_IMAGE_FILE}'
> +
> +    truncate -s ${ROOTFS_SIZE}K
> '${DEPLOY_DIR_IMAGE}/${EXT4_IMAGE_FILE}' +
> +    image_do_mounts
> +
> +    sudo chroot ${BUILDCHROOT_DIR} /sbin/mke2fs ${MKE2FS_ARGS} \
> +                -F -d '${PP_ROOTFS}'
> '${PP_DEPLOY}/${EXT4_IMAGE_FILE}' }
>  
> -addtask ext4_image before do_build after do_copy_boot_files
> +addtask ext4_image before do_build after do_copy_boot_files
> do_install_imager_deps do_ext4_image[prefuncs] = 'set_image_size'