具体错误如下：

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:20:b7:13/00:00:00:00:00/ef tag 0 dma 4096 in

res 51/40:00:27:b7:13/40:00:10:00:00/ef Emask 0x9 (media error)

ata1.00: status: { DRDY ERR }

ata1.00: error: { UNC }

ata1.00: configured for UDMA/133

ata1: EH complete

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:20:b7:13/00:00:00:00:00/ef tag 0 dma 4096 in

res 51/40:00:27:b7:13/40:00:10:00:00/ef Emask 0x9 (media error)

ata1.00: status: { DRDY ERR }

ata1.00: error: { UNC }

ata1.00: configured for UDMA/133

ata1: EH complete

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:20:b7:13/00:00:00:00:00/ef tag 0 dma 4096 in

res 51/40:00:27:b7:13/40:00:10:00:00/ef Emask 0x9 (media error)

ata1.00: status: { DRDY ERR }

ata1.00: error: { UNC }

ata1.00: configured for UDMA/133

sd 0:0:0:0: [sda] Unhandled sense code

sd 0:0:0:0: [sda] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE

sd 0:0:0:0: [sda] Sense Key : Medium Error [current] [descriptor]

Descriptor sense data with sense descriptors (in hex):

72 03 11 04 00 00 00 0c 00 0a 80 00 00 00 00 00

0f 13 b7 27

sd 0:0:0:0: [sda] Add. Sense: Unrecovered read error - auto reallocate failed

sd 0:0:0:0: [sda] CDB: Read(10): 28 00 0f 13 b7 20 00 00 08 00

end_request: I/O error, dev sda, sector 252950311

ata1: EH complete

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:20:b7:13/00:00:00:00:00/ef tag 0 dma 4096 in

res 51/40:00:27:b7:13/40:00:10:00:00/ef Emask 0x9 (media error)

ata1.00: status: { DRDY ERR }

ata1.00: error: { UNC }

ata1.00: configured for UDMA/133

ata1: EH complete

ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x0

ata1.00: BMDMA stat 0x24

ata1.00: failed command: READ DMA

ata1.00: cmd c8/00:08:20:b7:13/00:00:00:00:00/ef tag 0 dma 4096 in

res 51/40:00:27:b7:13/40:00:10:00:00/ef Emask 0x9 (media error)

ata1.00: status: { DRDY ERR }

ata1.00: error: { UNC }

ata1.00: configured for UDMA/133

ata1: EH complete

最后说的是如果按ctrl+d，系统会重启(上面的错误中没有记录)，如果输入root的密码，可以进入shell命令行。

我按照提示输入了root密码，进入shell后，使用df命令查看，发现到/var的时候，提示“No such file or directory”，然后我 ls /var ，发现里面空空如也，文件都不见了。但是发现df命令的“Size  Used Avail Use%”这几个值都挺正常的，从而判断并不是文件丢失，文件很可能是在某个地方，没有挂载到/var中而已。于是放入Centos安装光盘，重启，进入 rescure模式：

之后分别输入：

lvm vgscan

lvm vgchange -ay

lvm lvs

最后使用e2fsck命令修复一下LVM磁盘：

e2fsck -f -y /dev/mapper/VolGroup00-LogVol00

结果会告诉你修复了哪些东西，最后将光盘取出重启系统，一切都变正常了。

注意：如果不在rescure模式，运行lvm那三条命令，可能会出现“file-based locking initialization failed”错误。强制e2fsck可能会损坏分区数据，所以操作一定要在rescure模式下进行，切记。。