谁能帮我看一下openwrt的分区？
概要
使用一个编译好的Openwrt 固件烧写系统启动后，发现用户分区只有812M， 但实际上硬件eMMC存储为32G,可以通过修改固件分区表来调整，但是比较麻烦，本文验证一种更为简便的方法来找回消失的eMMc存储。
问题分析
启动系统后查看分区信息如下：
#df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 812M 664M 91M 88% /
tmpfs 512K 0 512K 0% /dev
tmpfs 987M 19M 968M 2% /tmp
cgroup 987M 0 987M 0% /sys/fs/cgroup
#lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
mmcblk0 179:0 0 28.9G 0 disk
├─mmcblk0p1 179:1 0 4M 0 part
├─mmcblk0p2 179:2 0 4M 0 part
├─mmcblk0p3 179:3 0 64M 0 part
├─mmcblk0p4 179:4 0 64M 0 part
├─mmcblk0p5 179:5 0 32M 0 part
├─mmcblk0p6 179:6 0 6G 0 part /
├─mmcblk0p7 179:7 0 128M 0 part
└─mmcblk0p8 179:8 0 22.6G 0 part
mmcblk0boot0 179:32 0 4M 1 disk
mmcblk0boot1 179:64 0 4M 1 disk
zram0 254:0 0 0B 0 disk
可以看出，分区mmcblk0p6被挂载为根分区，22.6G的mmcblk0p8闲在那儿呢。
解决
执行下以命令，挂载mmcblk0p8， 发现并未显示实际大小。
mount /dev/mmcblk0p8 /mnt/
df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 812M 664M 91M 88% /
tmpfs 512K 0 512K 0% /dev
tmpfs 987M 20M 967M 2% /tmp
cgroup 987M 0 987M 0% /sys/fs/cgroup
/dev/mmcblk0p8 23G 24K 21G 1% /mnt
#df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 812M 664M 91M 88% /
tmpfs 512K 0 512K 0% /dev
tmpfs 987M 19M 968M 2% /tmp
cgroup 987M 0 987M 0% /sys/fs/cgroup
/dev/mmcblk0p8 4.0M 283K 3.5M 8% /mnt
先对/dev/mmcblk0p8进行格式化，再次重新mount后分区大小显示正常了。
#mkfs.ext4 /dev/mmcblk0p8
mke2fs 1.46.5 (30-Dec-2021)
/dev/mmcblk0p8 contains a ext2 file system labelled 'userdata'
last mounted on Wed Dec 20 16:54:25 2023
Proceed anyway? (y,N) y
Discarding device blocks: done
Creating filesystem with 5926904 4k blocks and 1482752 inodes
Filesystem UUID: af5f8523-e705-4b11-8615-7c28df16aecb
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000
Allocating group tables: done
Writing inode tables: done
Creating journal (32768 blocks): done
Writing superblocks and filesystem accounting information: done
#umount /mnt/
#mount /dev/mmcblk0p8 /mnt/
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 812M 664M 91M 88% /
tmpfs 512K 0 512K 0% /dev
tmpfs 987M 20M 967M 2% /tmp
cgroup 987M 0 987M 0% /sys/fs/cgroup
/dev/mmcblk0p8 23G 24K 21G 1% /mnt
# lsblk
NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINTS
mmcblk0 179:0 0 28.9G 0 disk
├─mmcblk0p1 179:1 0 4M 0 part
├─mmcblk0p2 179:2 0 4M 0 part
├─mmcblk0p3 179:3 0 64M 0 part
├─mmcblk0p4 179:4 0 64M 0 part
├─mmcblk0p5 179:5 0 32M 0 part
├─mmcblk0p6 179:6 0 6G 0 part /
├─mmcblk0p7 179:7 0 128M 0 part
└─mmcblk0p8 179:8 0 22.6G 0 part /root
mmcblk0boot0 179:32 0 4M 1 disk
mmcblk0boot1 179:64 0 4M 1 disk
zram0 254:0 0 0B 0 disk
配置永久生效
先导出fstab配置。
#block detect > /etc/config/fstab
#cat /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 '/mnt'
option uuid 'af5f8523-e705-4b11-8615-7c28df16aecb'
option enabled '0'
修改/etc/config/fstab内容如下，使能系统自动mount mmcblk0p8到 /root。
config 'mount'
option target '/root'
option uuid 'af5f8523-e705-4b11-8615-7c28df16aecb'
option enabled '1'
重启系统后生效，
# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/root 812M 608M 147M 81% /
tmpfs 512K 0 512K 0% /dev
tmpfs 987M 18M 969M 2% /tmp
cgroup 987M 0 987M 0% /sys/fs/cgroup
/dev/mmcblk0p8 23G 57M 21G 1% /root
