linux 文件系统故障

现象描述：系统是centos，一次停电导致服务器关机。开机后，输入正确的密码，界面一闪而过，又是要接着输入密码，也不提示我密码错误。当我换到命令行下使用logoin登录时，也是这种情况，只不过这里一直是让我输入用户名和密码两种。

当我使用root用户登录时，一切正常，当使用新建的其他用户登录时，又一切很正常了

进入/home 目录下，执行ls  结果出现：Input/output error 

进入其他目录比如/var 目录执行是正常的

1，推测原因：磁盘老化导致坏道，异常操作导致文件node错乱、文件损坏等
2，修复方法：软件修复，单不能保证修复所有的错误。修复后如果一段时间内再次发生，请考虑磁盘质量问题。
修复过程:
1 df -TH #记录目标磁盘的类型，如ext2、ext3.记录挂在盘和挂在目录。如:/dev/sda3 /disk3
2 umount /dev/sda3  #取消挂载，如提示设备忙，请执行:  fuser -km /dev/sda3
3 fsck -t ext2 -y /dev/sda3#修复。"ext2"是第一步查看的磁盘类型。
4 mount /dev/sda3 /disk3/  #完成挂载
5 reboot #建议重启。
 

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如果是xfs文件系统：

修改包括三步：卸载，修复和检查重启

1)umount /dev/mapper/centos-home

 

2) xfs_repair /dev/mapper/centos-home Phase 1 - find and verify superblock... Phase 2 - using internal log - zero log... ERROR: The filesystem has valuable metadata changes in a log which needs to be replayed. Mount the filesystem to replay the log, and unmount it before re-running xfs_repair. If you are unable to mount the filesystem, then use the -L option to destroy the log and attempt a repair. Note that destroying the log may cause corruption -- please attempt a mount of the filesystem before doing this.

报错，提示使用-L参数：

xfs_repair -L /dev/vdb 
Phase 1 - find and verify superblock...
Phase 2 - using internal log
        - zero log...
ALERT: The filesystem has valuable metadata changes in a log which is being
destroyed because the -L option was used.
        - scan filesystem freespace and inode maps...
agi unlinked bucket 11 is 7499 in ag 3 (inode=805313867)
sb_icount 7296, counted 13184
sb_ifree 111, counted 644
sb_fdblocks 78500862, counted 59430965
        - found root inode chunk
Phase 3 - for each AG...
        - scan and clear agi unlinked lists...
        - process known inodes and perform inode discovery...
        - agno = 0
        - agno = 1
        - agno = 2
        - agno = 3
        - process newly discovered inodes...
Phase 4 - check for duplicate blocks...
        - setting up duplicate extent list...
        - check for inodes claiming duplicate blocks...
        - agno = 0
        - agno = 1
        - agno = 3
        - agno = 2
Phase 5 - rebuild AG headers and trees...
        - reset superblock...
Phase 6 - check inode connectivity...
        - resetting contents of realtime bitmap and summary inodes
        - traversing filesystem ...
        - traversal finished ...
        - moving disconnected inodes to lost+found ...
disconnected inode 805313867, moving to lost+found
Phase 7 - verify and correct link counts...
Maximum metadata LSN (815:101693) is ahead of log (1:2).
Format log to cycle 818.
done

修复成功。

3) 再次挂载：mount /dev/mapper/centos-home /home

df -h  确认挂载成功

4） 重启一切正常