OpenWRT - Expanding root partition and filesystem - 70-rootpt-resize

70-rootpt-resize.sh

# https://openwrt.org/docs/guide-user/advanced/expand_root

if [ ! -e /etc/rootpt-resize ] && lock -n /var/lock/root-resize; then
  (
    set -eux
    date
    ROOT_BLK="$(readlink -f /sys/dev/block/"$(awk -e '$9=="/dev/root"{print $3}' /proc/self/mountinfo)")"
    ROOT_DISK="/dev/$(basename "${ROOT_BLK%/*}")"
    ROOT_PART="${ROOT_BLK##*[^0-9]}"
    parted -f -s "${ROOT_DISK}" resizepart "${ROOT_PART}" 100%
    mount_root done

    if [ -e /boot/cmdline.txt ]; then
      set -eux
      NEW_UUID=`blkid ${ROOT_DISK}p${ROOT_PART} | sed -n 's/.*PARTUUID="\([^"]*\)".*/\1/p'`
      sed -i "s/PARTUUID=[^ ]*/PARTUUID=${NEW_UUID}/" /boot/cmdline.txt
    fi
  ) 2>&1 | tee -a /etc/rootpt-resize

  reboot
fi
exit 1