求救，filesystem 的问题，无法进入

我是因为磁盘空间满了，所以插入移动硬盘，想将电脑内的文件拷贝出去，但是linux没有识别移动硬盘，所以选择重起，重起后就出现问题，显示如下：
Checking root file system
WARNING: Your /etc/fstab does not contain the fsck passno field. I will kludge around things for you, but you should fix your /etc/fstab file as soon as you can.
fsck.ext2: Is a directory while trying to open / [FAILED]
*** An error occurred dureing the file system check.
*** Dropping you to a shell; the system will reboot when you leave the shell.
*** Warning -- SELinux is active
*** Disabling security enforcement for system recovery.
*** Run 'setenforce 1' to reenable.
Give root password for maintenance
(or type Control - D to continue):
用Control-D后，系统重起，回到该界面，输入密码显示
(Repair filesystem) 1 #
输入init 1 又回到该界面，输入init 5，最后出现的图形界面显示
I could not start the X server (your graphical environment) due to some internal error........
startkde 显示
Not enough free disk space on /tmp
用 fsck 命令得到
WARNING: Your /etc/fstab does not contain the fsck passno field. I will kludge around thins for you, but you should fix your /etc/fstab file as soon as you can.
用e2fsck -b 8193 /dev/sda3得到
/boot was not cleanly unmounted, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 1: Checking directory connectivity
Pass 1: Checking reference counts
Pass 1: Checking group summary information
用umonut 命令 to make sure sda3 is unmounted, 还是不行
进入单用户模式下，
WARNING!!! Running e2fsck on a mounted filesystem may cause
SEVERE filesystem damage.
不敢再往下弄了，请教那位高手能详细的告诉我如何才能修复superblock的问题阿？急等，非常感谢(6)m:b