emmc闪存分区挂载

时间：2023-04-08 18:37:00 r68mt片式功率电感

背景

开发板中，emmc设备参数为32G闪存，但实际使用命令查询远远不够，因此怀疑有未挂载的分区

分区查询

执行fdisk -l，显示出/dev/mmcblk0(即闪存)有29G

Disk /dev/mmcblk0: 29 GB, 31037849600 bytes, 60620800 sectors 947200 cylinders, 4 heads, 16 sectors/track Units: cylinders of 64 * 512 = 32768 bytes  Disk /dev/mmcblk0 doesn't contain a valid partition table Disk /dev/mmcblk0p1: 2048 MB, 2147483648 bytes, 4194304 sectors 65536 cylinders, 4 heads, 16 sectors/track Units: cylinders of 64 * 512 = 32768 bytes  Disk /dev/mmcblk0p1 doesn't contain a valid partition table Disk /dev/mmcblk0boot1: 4 MB, 4194304 bytes, 8192 sectors 128 cylinders, 4 heads, 16 sectors/track Units: cylinders of 64 * 512 = 32768 bytes  Disk /dev/mmcblk0boot1 doesn't contain a valid partition table Disk /dev/mmcblk0boot0: 4 MB, 4194304 bytes, 8192 sectors 128 cylinders, 4 heads, 16 sectors/track Units: cylinders of 64 * 512 = 32768 bytes  Disk /dev/mmcblk0boot0 doesn't contain a valid partition table Note: sector size is 4096 (not 512) Disk /dev/sda: 7 MB, 8384512 bytes, 16376 sectors 127 cylinders, 1 heads, 16 sectors/track Units: cylinders of 16 * 4096 = 65536 bytes

使用cat /proc/partitions查询分区，发现mmcblk0有很多分区，包括mmcblk0p4分区有21.9G，怀疑该分区未挂载

major minor  #blocks  name     1        0      16384 ram0    1        1      16384 ram1    1        2      16384 ram2    1        3      16384 ram3    1        4      16384 ram4    1        5      16384 ram5    1        6      16384 ram6    1        7      16384 ram7    1        8      16384 ram8    1        9      16384 ram9    1       10      16384 ram10    1       11      16384 ram11    1       12      16384 ram12    1       13      16384 ram13    1       14      16384 ram14    1       15      16384 ram15  179        0   30310400 mmcblk0  179        1    2097152 mmcblk0p1  179        2    4194304 mmcblk0p2  179        3    1048576 mmcblk0p3  179        4   22970368 mmcblk0p4 # 该处未挂载  179       24       4096 mmcblk0rpmb  179       16       4096 mmcblk0boot1  179        8       4096 mmcblk0boot0    8        0       8188 sda

使用df -h查询挂载情况，确实少了21.9G

Filesystem                Size      Used Available Use% Mounted on rootfs                  485.0M     29.5M    455.5M   6% / devtmpfs                485.0M         0    485.0M   0% /dev tmpfs                   490.8M         0    490.8M   0% /dev/shm tmpfs                   490.8M    108.0K    490.7M   0% /tmp tmpfs                   490.8M     12.0K    490.8M   0% /run /dev/mmcblk0.xx           3.9G    612.1M      3.1G  16% /xx /dev/mmcblk0.zz         975.9M      2.5M    906.2M   0% /zz

cd /dev进入文件夹
执行ls -l | grep mmcblk0，查看到mmcblk0.reserved是闪存p4分区软链接

brw-------    1 root     root      179,   0 Jan  1  1970 mmcblk0 lrwxrwxrwx    1 root     root            14 Sep 23 00:16 mmcblk0.boot -> /dev/mmcblk0p1 lrwxrwxrwx    1 root     root            14 Sep 23 00:16 mmcblk0.xx -> /dev/mmcblk0p2 lrwxrwxrwx    1 root     root            14 Sep 23 00:16 mmcblk0.zz -> /dev/mmcblk0p3 lrwxrwxrwx    1 root     root            14 Sep 23 00:16 mmcblk0.reserved -> /dev/mmcblk0p4 # p4的软链接 brw-------    1 root     root      179,   8 Jan  1  1970 mmcblk0boot0 brw-------    1 root     root      179,  16 Jan  1  1970 mmcblk0boot1 brw-------    1 root     root      179,   1 Jan  1  1970 mmcblk0p1 brw-------    1 root     root      179,   2 Jan  1  1970 mmcblk0p2 brw-------    1 root     root      179,   3 Jan  1  1970 mmcblk0p3 brw-------    1 root     root      179,   4 Jan  1  1970 mmcblk0p4 brw-------    1 root     root      179,  24 Jan  1  1970 mmcblk0rpmb

挂载p4分区

mkdir /opt，创建文件夹
mkfs.vfat /dev/mmcblk0p4.格式化硬盘(自行选择格式)
mount /dev/mmcblk0.reserved /opt，挂载分区
(可选)需要启动挂载时，自行找到启动命令。mount语句放入

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emmc闪存分区挂载

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