学步园

　　1、mount:
　　用于查看哪个模块输入只读，一般显示为：

　　[root@localhost ~]# mount
         /dev/cciss/c0d0p2 on / type ext3 (rw)
         proc on /proc type proc (rw)
         sysfs on /sys type sysfs (rw)
         devpts on /dev/pts type devpts (rw,gid=5,mode=620)
         /dev/cciss/c0d0p7 on /home type ext3 (rw)
         /dev/cciss/c0d0p6 on /var type ext3 (rw)
         /dev/cciss/c0d0p3 on /usr type ext3 (rw)
        /dev/cciss/c0d0p1 on /boot type ext3 (rw)
        tmpfs on /dev/shm type tmpfs (rw)
        none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
        sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)
        /dev/dm-0 on /home/book/upload/BookFile1 type ext3 (rw)
        /dev/dm-1 on /home/book/upload/BookFile2 type ext3 (rw)
        /dev/dm-2 on /backup type ext3 (rw)
        /dev/dm-3 on /home/book/upload/BookFile3 type ext3 (ro)

　　2、如果发现有ro，就重新mount，或者umount以后再remount

　　3、umount /dev/dm-3
　　如果发现有提示“device is busy”，找到是什么进程使得他busy

　　fuser -m /mnt/data 将会显示使用这个模块的pid
　　fuser -mk /mnt/data 将会直接kill那个pid

　　然后重新mount即可。

　　4、还有一种方法是直接remount，命令为

　　mount -o rw,remount /mnt/data 没有用过，看到网络上有这么写。

二、具体深入的做法，情况不同可以自行选择：

服务器/var/log/messages报错 ：

end_request: I/O error, dev sda, sector 122194293 Buffer I/O error on device sda1, logical block 446493 lost page

write due to I/O error on sda1

下面是整个处理全过程

[root@localhost ~]# fdisk -lu #第一步 ：找出本地扇片所在的分区。
Disk /dev/cciss/c0d0: 146.7 GB, 146778685440 bytes
255 heads, 32 sectors/track, 35132 cylinders, total 286677120 sectors
Units = sectors of 1 * 512 = 512 bytes

           Device Boot      Start         End      Blocks   Id  System
/dev/cciss/c0d0p1   *          32    78711359    39355664   83  Linux
/dev/cciss/c0d0p2        78711360   142114559    31701600   83  Linux
/dev/cciss/c0d0p3       142114560   185044319    21464880   83  Linux
/dev/cciss/c0d0p4       185044320   286677119    50816400    5  Extended
/dev/cciss/c0d0p5       185044352   201625439     8290544   82  Linux swap / Solaris
/dev/cciss/c0d0p6       201625472   207965759     3170144   83  Linux
/dev/cciss/c0d0p7       207965792   286677119    39355664   83  Linux

[root@localhost ~]# tune2fs -l /dev/dm-3 |grep "Block size" #找到block大小。
Block size: 4096

(122194293-75778605)*512/4096 =528691 利用公式算出逻辑块地址

b = (int)((L-S)*512/B)

[root@localhost ~]#  debugfs
debugfs 1.35 (28-Feb-2004)
debugfs: open /deb/dm-3
/deb/dm-3: No such file or directory while opening filesystem
debugfs: open /dev/dm-3
debugfs: icheck 582391
Block Inode number
582391 277584
debugfs: ncheck 277584
Inode Pathname
277584 /users/inn.net.cn/data/upload/download/innshow004.rar
debugfs: quit
[root@localhost ~]# dd if=/dev/zero of=/dev/dm-3 bs=4096 count=1 seek=582391 #找到这个快的文件之后，需要做好备份，我们强制把它设置为0字节。

[root@localhost ~]#  sync