Expanding root partition and filesystem

Introduction

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

This instruction expands OpenWrt root partition and filesystem on x86 target.

Follow the automated section for quick setup.

Features

Support `ext4` and `squashfs` image types.
Automatically identify the root partition and filesystem.
Expand the root partition and filesystem using free space.
Preserve the scripts through firmware upgrade.
Automatically run after firmware upgrade.

Instructions

Configure startup scripts

cat << "EOF" > /etc/uci-defaults/70-rootpt-resize
if [ ! -e /etc/rootpt-resize ] \
  && type parted > /dev/null \
  && lock -n /var/lock/root-resize
then
  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
  touch /etc/rootpt-resize
  if [ -e /boot/cmdline.txt ]
  then
    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
  reboot
fi
exit 1
EOF

cat << "EOF" > /etc/uci-defaults/80-rootfs-resize
if [ ! -e /etc/rootfs-resize ] \
  && [ -e /etc/rootpt-resize ] \
  && type losetup > /dev/null \
  && type resize2fs > /dev/null \
  && lock -n /var/lock/root-resize
then
  ROOT_BLK="$(readlink -f /sys/dev/block/"$(awk -e '$9=="/dev/root"{print $3}' /proc/self/mountinfo)")"
  ROOT_DEV="/dev/${ROOT_BLK##*/}"
  LOOP_DEV="$(awk -e '$5=="/overlay"{print $9}' /proc/self/mountinfo)"
  if [ -z "${LOOP_DEV}" ]
  then
    LOOP_DEV="$(losetup -f)"
    losetup "${LOOP_DEV}" "${ROOT_DEV}"
  fi
  resize2fs -f "${LOOP_DEV}"
  mount_root
  done
  touch /etc/rootfs-resize
  reboot
fi
exit 1
EOF

cat << "EOF" >> /etc/sysupgrade.conf
/etc/uci-defaults/70-rootpt-resize
/etc/uci-defaults/80-rootfs-resize
EOF

Examples

Install packages

opkg update
opkg install parted losetup resize2fs

Expand root partition/filesystem

sh /etc/uci-defaults/70-rootpt-resize

Automated

opkg update
opkg install parted losetup resize2fs
wget -U "" -O expand-root.sh "https://openwrt.org/_export/code/docs/guide-user/advanced/expand_root?codeblock=0"
. ./expand-root.sh