The hidden writable filesystem on my R4S squashfs image is ext4 instead of f2fs.
My first ever attempt at expanding the hidden file system for a writable overlay failed on 22.03.2 squashfs image for my R4S.
(The R4S uses an SD card for storage so there is typically extra space to expand into.)
All the directions I found for expanding the overlay filesystem on a squashfs image were for f2fs.
It looks like this one is a hybrid setup with ext4 overlay on the squashfs image.
I found a working solution. Simply use the ext4 resizing process on the loop mount.
I did the following one line at a time after having the fsck.f2fs -f ${LOOP} command fail.
This is done on the live router running OpenWrt after first boot.
opkg update
opkg install losetup e2fsprogs resize2fs
LOOP="$(losetup -n -O NAME | sort | sed -n -e "1p")"
ROOT="$(losetup -n -O BACK-FILE ${LOOP} | sed -e "s|^|/dev|")"
OFFS="$(losetup -n -O OFFSET ${LOOP})"
LOOP="$(losetup -f)"
losetup -o ${OFFS} ${LOOP} ${ROOT}
e2fsck -f ${LOOP}
mount ${LOOP} /mnt
umount ${LOOP}
resize2fs ${LOOP}
reboot
I did not do this all in one pass from a clean installation yet so I'm not 100% that it is
good to use.
Values for variables set in above command list:
root@R4S-wrt:~# echo ${OFFS} ${LOOP} ${ROOT}
9043968 /dev/loop1 /dev/mmcblk1p2
I adapted the process for f2fs:
and ext4:
My Resizing session log after having fsck.f2fs -f ${LOOP} fail and some required programs were already installed:
root@R4S-wrt:~# LOOP="$(losetup -n -O NAME | sort | sed -n -e "1p")"
root@R4S-wrt:~# ROOT="$(losetup -n -O BACK-FILE ${LOOP} | sed -e "s|^|/dev|")"
root@R4S-wrt:~# OFFS="$(losetup -n -O OFFSET ${LOOP})"
root@R4S-wrt:~# LOOP="$(losetup -f)"
root@R4S-wrt:~# losetup -o ${OFFS} ${LOOP} ${ROOT}
root@R4S-wrt:~# fsck.ext4 -f ${LOOP}
e2fsck 1.46.5 (30-Dec-2021)
rootfs_data: recovering journal
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
/lost+found not found. Create<y>? yes
Pass 4: Checking reference counts
Pass 5: Checking group summary information
rootfs_data: ***** FILE SYSTEM WAS MODIFIED *****
rootfs_data: 376/24384 files (0.3% non-contiguous), 14666/97664 blocks
root@R4S-wrt:~# mount ${LOOP} /mnt
root@R4S-wrt:~# umount ${LOOP}
root@R4S-wrt:~# resize2fs ${LOOP}
resize2fs 1.46.5 (30-Dec-2021)
Please run 'e2fsck -f /dev/loop1' first.
root@R4S-wrt:~# e2fsck -f /dev/loop1
e2fsck 1.46.5 (30-Dec-2021)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
rootfs_data: 381/24384 files (0.3% non-contiguous), 14721/97664 blocks
root@R4S-wrt:~# resize2fs ${LOOP}
resize2fs 1.46.5 (30-Dec-2021)
Resizing the filesystem on /dev/loop1 to 4185472 (1k) blocks.
The filesystem on /dev/loop1 is now 4185472 (1k) blocks long.
root@R4S-wrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 8.8M 8.8M 0 100% /rom
tmpfs 1.9G 996.0K 1.9G 0% /tmp
/dev/loop0 83.9M 2.9M 74.3M 4% /overlay
overlayfs:/overlay 83.9M 2.9M 74.3M 4% /
tmpfs 512.0K 0 512.0K 0% /dev
/dev/sda1 9.4G 11.6M 9.4G 0% /mnt/usb-flsh-p1
root@R4S-wrt:~# reboot
root@R4S-wrt:~# Connection to 192.168.3.1 closed by remote host.
Connection to 192.168.3.1 closed.
$ ssh root@192.168.3.1
root@192.168.3.1's password:
BusyBox v1.35.0 (2022-10-18 18:13:41 UTC) built-in shell (ash)
_______ ________ __
| |.-----.-----.-----.| | | |.----.| |_
| - || _ | -__| || | | || _|| _|
|_______|| __|_____|__|__||________||__| |____|
|__| W I R E L E S S F R E E D O M
-----------------------------------------------------
OpenWrt 22.03.2, r19803-9a599fee93
-----------------------------------------------------
root@R4S-wrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 8.8M 8.8M 0 100% /rom
tmpfs 1.9G 96.0K 1.9G 0% /tmp
/dev/loop0 3.7G 2.9M 3.5G 0% /overlay
overlayfs:/overlay 3.7G 2.9M 3.5G 0% /
tmpfs 512.0K 0 512.0K 0% /dev
/dev/sda1 9.4G 11.6M 9.4G 0% /mnt/usb-flsh-p1
root@R4S-wrt:~#
Note that fsck.ext4 is just a link to e2fsck:
root@R4S-wrt:~# ls -l /usr/sbin/fsck.ext4
lrwxrwxrwx 1 root root 6 Oct 14 18:44 /usr/sbin/fsck.ext4 -> e2fsck
My NanoPi R4S 22.03.2 squashfs image was created by adding several packages on the firmware selector and letting it generate a custom build.
https://firmware-selector.openwrt.org/?version=22.03.2&target=rockchip%2Farmv8&id=friendlyarm_nanopi-r4s
Relevant filesystems:
root@R4S-wrt:~# mount
/dev/root on /rom type squashfs (ro,relatime)
...
/dev/loop0 on /overlay type ext4 (rw,noatime)
overlayfs:/overlay on / type overlay (rw,noatime,lowerdir=/,upperdir=/overlay/upper,workdir=/overlay/work)
Original filesystem sizes before resizing:
root@R4S-wrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 8.8M 8.8M 0 100% /rom
tmpfs 1.9G 100.0K 1.9G 0% /tmp
/dev/loop0 83.9M 2.8M 74.4M 4% /overlay
overlayfs:/overlay 83.9M 2.8M 74.4M 4% /
tmpfs 512.0K 0 512.0K 0% /dev
Filesystem sizes after resizing:
root@R4S-wrt:~# df -h
Filesystem Size Used Available Use% Mounted on
/dev/root 8.8M 8.8M 0 100% /rom
tmpfs 1.9G 100.0K 1.9G 0% /tmp
/dev/loop0 3.7G 2.9M 3.5G 0% /overlay
overlayfs:/overlay 3.7G 2.9M 3.5G 0% /
tmpfs 512.0K 0 512.0K 0% /dev
Original partition info before resizing:
root@OpenWrt:~# fdisk -l /dev/mmcblk1
Disk /dev/mmcblk1: 58.94 GiB, 63281561600 bytes, 123596800 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5452574f
Device Boot Start End Sectors Size Id Type
/dev/mmcblk1p1 * 65536 98303 32768 16M 83 Linux
/dev/mmcblk1p2 131072 344063 212992 104M 83 Linux
Partition info after resizing:
root@R4S-wrt:~# fdisk -l /dev/mmcblk1
Disk /dev/mmcblk1: 58.94 GiB, 63281561600 bytes, 123596800 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x5452574f
Device Boot Start End Sectors Size Id Type
/dev/mmcblk1p1 * 65536 98303 32768 16M 83 Linux
/dev/mmcblk1p2 131072 8519679 8388608 4G 83 Linux
I hope this helps someone else!
