Openwrt版本为OpenWrt Chaos Calmer 15.05
一、安装需要的包
opkg update opkg install block-mount kmod-fs-ext4 kmod-usb-storage-extras
二、挂载U盘
把U盘进行格式化成ext4
mount /dev/sda1 /mnt tar -C /overlay -cvf - . | tar -C /mnt -xf - umount /mnt 三、写入命令
block detect > /etc/config/fstab; \ sed -i s/option$'\t'enabled$'\t'\'0\'/option$'\t'enabled$'\t'\'1\'/ /etc/config/fstab; \ sed -i s#/mnt/sda1#/overlay# /etc/config/fstab; \ cat /etc/config/fstab; 查看fstab文件，配置是否和下面一样
vi /etc/config/fstab config 'global' option anon_swap '0' option anon_mount '0' option auto_swap '1' option auto_mount '1' option delay_root '5' option check_fs '0' config 'mount' option target '/overlay' option uuid 'c91232a0-c50a-4eae-adb9-14b4d3ce3de1' option fstype 'ext4' option enabled '1' config 'swap' option uuid '08b4f0a3-f7ab-4ee1-bde9-55fc2481f355' option enabled '1' config 'mount' option target '/data' option uuid 'c1068d91-863b-42e2-bcb2-b35a241b0fe2' option enabled '1' 检查能否挂载成功
root@OpenWrt:~# mount /dev/sda1 /overlay root@OpenWrt:~# df Filesystem 1K-blocks Used Available Use% Mounted on rootfs 896 244 652 27% / /dev/root 2048 2048 0 100% /rom tmpfs 14708 64 14644 0% /tmp /dev/mtdblock6 7759872 477328 7221104 6% /overlay overlayfs:/overlay 896 244 652 27% / tmpfs 512 0 512 0% /dev /dev/sda1 7759872 477328 7221104 6% /overlay root@OpenWrt:~# 重启路由器完成操作
root@OpenWrt:~# df Filesystem 1K-blocks Used Available Use% Mounted on rootfs 7759872 477328 7221104 6% / /dev/root 2048 2048 0 100% /rom tmpfs 14708 64 14644 0% /tmp /dev/mtdblock6 7759872 477328 7221104 6% /overlay overlayfs:/overlay 7759872 477328 7221104 6% / tmpfs 512 0 512 0% /dev /dev/sda1 7759872 477328 7221104 6% /overlay /dev/sda3 242846048 163864 230323224 0% /data root@OpenWrt:~#
参考：https://wiki.openwrt.org/doc/howto/extroot
