First, add space into the Openwrt VM. Taking proxmox as an example, go to Openwrt VM -> hardware -> hard disk -> disk -> action -> resize.
Second, copy and paste the follwing into a sh file expand-root.sh:
# 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
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 Last, run the sh file: ./expand-root.sh