In the email from Monday, 11 July 2022 11:16:02 +03 user Tobias Schmidl wrote:

> If the disk is too small, resizing might have detrimental effects.

> Because of aligning issues, it could happen the the final partition is

> _smaller_ than desired, which might lead to an unusable last partition.

>

> Signed-off-by: Tobias Schmidl <tobiasschmidl@siemens.com>

> ---

>  .../files/expand-last-partition.sh               | 16 ++++++++++++++++

>  1 file changed, 16 insertions(+)

>

> diff --git

> a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh

> b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh

> index c0edde7..0aa1063 100755

> ---

> a/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh

> +++

> b/meta/recipes-support/expand-on-first-boot/files/expand-last-partition.sh

> @@ -22,6 +22,22 @@ if [ "${ROOT_DEV}" = "${BOOT_DEV}" ]; then

>      exit 1

>  fi

>

> +# this value is in blocks. Normally a block has 512 bytes.

> +BUFFER_SIZE=32768

> +BOOT_DEV_NAME=${BOOT_DEV##*/}

> +DISK_SIZE="$(cat /sys/class/block/"${BOOT_DEV_NAME}"/size)"

> +ALL_PARTS_SIZE=0

> +for PARTITION in /sys/class/block/"${BOOT_DEV_NAME}"[1-9]*; do

It seems to be working only for something like 'sda' => 'sda1'.

For RPi I have 

root@isar:~# ls /sys/class/block/ | grep mmc
mmcblk0
mmcblk0p1
mmcblk0p2

So, "p" suffix is required.

Some other devices (like nvme) also need some prefix.

> +    PART_SIZE=$(cat "${PARTITION}"/size)

> +    ALL_PARTS_SIZE=$((ALL_PARTS_SIZE + PART_SIZE))

> +done

> +

> +MINIMAL_SIZE=$((ALL_PARTS_SIZE + BUFFER_SIZE))

> +if [ "$DISK_SIZE" -lt "$MINIMAL_SIZE" ]; then

> +    echo "Disk is practically already full, doing nothing." >&2

> +    exit 0

> +fi

> +

>  LAST_PART="$(sfdisk -d "${BOOT_DEV}" 2>/dev/null | tail -1 | cut -d ' ' -f

> 1)"

>

>  # Transform the partition table as follows:

--

Uladzimir Bely