超级块修复（SF03或PFR二代）

*有一批设备开启启动的脚本加了fsck.ext4 之后，开机之后仍是掉盘

             原因：执行mount 及fsck.ext4 的时候报超级块太大无法读取导致的

             The superblock could not be read or does not describe a correct ext4  filesystem.  If the device is valid and it really contains an ext4 filesystem (and not swap or ufs or something else), then the superblock  is corrupt, and you might try running e2fsck with an alternate superblock:  e2fsck -b 8193 <device>

解决方案：

1：找到坏道的iNode号

         mke2fs -n /dev/xxx

2：对特定的iNode号进行修复

         e2fsck -b block_number /dev/mmcblk0p4

3：reboot

4：修复完毕