OP一直有这个问题，就是把镜像写入到SD卡或者本地磁盘后，默认只使用了100多M的空间，导致SD卡有大量存储空间限制。

之前一直使用的方法是 fdisk 删除，重建分区大法，不过这方法会导致分区UUID变更，需要更新GRUB.CFG文件才行。

今天刚安装了OP最新稳定版 OpenWrt 23.05.0，就按照官方最新的DOC试试新方法。

ssh 登录系统,可见磁盘mmcblk0p2 需要扩容。

BusyBox v1.36.1 (2023-10-09 21:45:35 UTC) built-in shell (ash)

  _______                     ________        __
 |       |.-----.-----.-----.|  |  |  |.----.|  |_
 |   -   ||  _  |  -__|     ||  |  |  ||   _||   _|
 |_______||   __|_____|__|__||________||__|  |____|
          |__| W I R E L E S S   F R E E D O M
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 OpenWrt 23.05.0, r23497-6637af95aa
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root@OpenWrt:~# uname -a
Linux OpenWrt 5.15.134 #0 SMP Mon Oct 9 21:45:35 2023 aarch64 GNU/Linux
root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root               102.3M     16.8M     83.5M  17% /
tmpfs                   245.2M     92.0K    245.1M   0% /tmp
tmpfs                   512.0K         0    512.0K   0% /dev
root@OpenWrt:~# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
mmcblk0     179:0    0 14.4G  0 disk
├─mmcblk0p1 179:1    0   20M  0 part
└─mmcblk0p2 179:2    0  104M  0 part /

更新OPKG源，安装需要用到工具 parted losetup resize2fs.

root@OpenWrt:~# opkg update
Downloading https://downloads.openwrt.org/releases/23.05.0/targets/sunxi/cortexa53/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_core
Downloading https://downloads.openwrt.org/releases/23.05.0/targets/sunxi/cortexa53/packages/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_base
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/luci/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_luci
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/luci/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_packages
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/routing/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_routing
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/routing/Packages.sig
Signature check passed.
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/telephony/Packages.gz
Updated list of available packages in /var/opkg-lists/openwrt_telephony
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/telephony/Packages.sig
Signature check passed.
root@OpenWrt:~# opkg install parted losetup resize2fs
Installing parted (3.6-1) to root...
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/parted_3.6-1_aarch64_cortex-a53.ipk
Installing libparted (3.6-1) to root...
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/packages/libparted_3.6-1_aarch64_cortex-a53.ipk
Installing libreadline8 (8.2-1) to root...
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/libreadline8_8.2-1_aarch64_cortex-a53.ipk
Installing losetup (2.39-2) to root...
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/losetup_2.39-2_aarch64_cortex-a53.ipk
Installing resize2fs (1.47.0-2) to root...
Downloading https://downloads.openwrt.org/releases/23.05.0/packages/aarch64_cortex-a53/base/resize2fs_1.47.0-2_aarch64_cortex-a53.ipk
Configuring resize2fs.
Configuring losetup.
Configuring libparted.
Configuring libreadline8.
Configuring parted.

扩容磁盘mmcblk0 分区2,第一次重启。

root@OpenWrt:~# echo -e "ok\nfix" | parted -l ---pretend-input-tty
Model: SD SD16G (sd/mmc)
Disk /dev/mmcblk0: 15.5GB
Sector size (logical/physical): 512B/512B
Partition Table: msdos
Disk Flags:

Number  Start   End     Size    Type     File system  Flags
 1      1049kB  22.0MB  21.0MB  primary  fat16        boot, lba
 2      23.1MB  132MB   109MB   primary  ext2


root@OpenWrt:~# parted -s /dev/mmcblk0 resizepart 2 100%
root@OpenWrt:~# reboot

扩容分区 mmcblk0p2 对应的ext文件系统 /，第二次重启。

root@OpenWrt:~# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
mmcblk0     179:0    0 14.4G  0 disk
├─mmcblk0p1 179:1    0   20M  0 part
└─mmcblk0p2 179:2    0 14.4G  0 part / #这里可以看到分区2已经被扩容了
root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root               102.3M     20.0M     80.3M  20% /
tmpfs                   245.2M     88.0K    245.1M   0% /tmp
tmpfs                   512.0K         0    512.0K   0% /dev
root@OpenWrt:~# losetup /dev/loop1 /dev/mmcblk0p2
root@OpenWrt:~# resize2fs -f /dev/loop1
resize2fs 1.47.0 (5-Feb-2023)
Resizing the filesystem on /dev/loop1 to 3779072 (4k) blocks.
The filesystem on /dev/loop1 is now 3779072 (4k) blocks long.

root@OpenWrt:~# reboot

2次重启完成后，进入系统，扩容已经完成。

root@OpenWrt:~# df -h
Filesystem                Size      Used Available Use% Mounted on
/dev/root                14.2G     20.0M     14.2G   0% / #文件也已经被扩容
tmpfs                   245.2M     84.0K    245.1M   0% /tmp
tmpfs                   512.0K         0    512.0K   0% /dev
root@OpenWrt:~# lsblk
NAME        MAJ:MIN RM  SIZE RO TYPE MOUNTPOINTS
mmcblk0     179:0    0 14.4G  0 disk
├─mmcblk0p1 179:1    0   20M  0 part
└─mmcblk0p2 179:2    0 14.4G  0 part /

相对于fdisk，这个还是比较方便的。

参考文档：
https://openwrt.org/docs/guide-user/installation/openwrt_x86#expanding_root_partition
https://openwrt.org/docs/guide-user/installation/openwrt_x86#expanding_root_filesystem
https://openwrt.org/docs/guide-user/installation/installation_methods/sd_card
https://openwrt.org/docs/guide-user/advanced/expand_root