Expanding root partition and filesystem

Expanding root partition and filesystem

This article relies on the following:

Accessing web interface / command-line interface
Managing configs / packages / services / logs

Introduction

This instruction expands OpenWrt root partition and filesystem on x86 target.
Follow the automated section for quick setup, or click the expand link below for manual 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 (manual)

Click to display ⇲

Click to hide ⇱

Manual installation of script (C&P)

# 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

Execution Pre 25.12

# Install packages
opkg update
opkg install parted losetup resize2fs blkid
 
# Expand root partition/filesystem
sh /etc/uci-defaults/70-rootpt-resize

Execution Post 25.12

# Install packages
apk update
apk add parted losetup resize2fs blkid
 
# Expand root partition/filesystem
sh /etc/uci-defaults/70-rootpt-resize

Automated Pre 25.12

# Install packages
opkg update
opkg install parted losetup resize2fs blkid
 
# Download expand-root.sh
wget -U "" -O expand-root.sh "https://openwrt.org/_export/code/docs/guide-user/advanced/expand_root?codeblock=0"
 
# Source the script (creates /etc/uci-defaults/70-rootpt-resize and /etc/uci-defaults/80-rootpt-resize, and adds them to /etc/sysupgrade.conf so they will be re-run after a sysupgrade)
. ./expand-root.sh
 
# Resize root partition and filesystem (will resize partiton, reboot resize filesystem, and reboot again)
sh /etc/uci-defaults/70-rootpt-resize

Automated Post 25.12

# Install packages
apk update
apk add parted losetup resize2fs blkid
 
# Download expand-root.sh
wget -U "" -O expand-root.sh "https://openwrt.org/_export/code/docs/guide-user/advanced/expand_root?codeblock=0"
chmod +x expand-root.sh
 
# Source the script (creates /etc/uci-defaults/70-rootpt-resize and /etc/uci-defaults/80-rootfs-resize, and adds them to /etc/sysupgrade.conf so they will be re-run after a sysupgrade)
. ./expand-root.sh
 
# Resize root partition and filesystem (will resize partiton, reboot resize filesystem, and reboot again)
sh /etc/uci-defaults/70-rootpt-resize

Re-running Script

If the root partition has already been expanded and the expand-root.sh script has previously run, attempting to run it again will not work by default. To perform an additional root expansion, you need remove previous script flags:

rm /etc/rootpt-resize
rm /etc/rootfs-resize

Open the /etc/sysupgrade.conf file and remove the following lines:

/etc/uci-defaults/70-rootpt-resize
/etc/uci-defaults/80-rootfs-resize

This ensures that the system no longer considers the scripts as already executed and then you can re-run script.

Table of Contents