Linux开机出现welcome to emergency mode! 解决方法

Linux开机出现welcome to emergency mode! 解决方法

Linux开机出现welcome to emergency mode! 解决方法

linux服务器中有一台安装KVM虚拟机重启不了，直接reboot，发现宿主机起不来

Welcome to emergency mode! After logging in, type "journalctl -xb" to view
system logs,"systemctl  reboot" to reboot ,"systemctl default" or ^D to
 try again to boot into default mode.
Give root password for maintenance
(or type Control-D to continue):

进入开机界面如图，进入救援模式

１.输入密码登录root账户; ２.执行命令 journalctl -xb 查看日志输出，搜索关键字”fsck failed”（输入/，然后输入关键字后回车，通过/n查看上一个/下一个匹配项），在错误提示信息附近可以看到错误相关的设备，用红标记，例如我的是/dev/disk/*;

查看 cat /etc/fstab

 # cat /etc/fstab
​
/dev/mapper/cl-root     /                       xfs     defaults        0 0
UUID=f51f5108-cb0-4a5f-ab58-aed88252dbbd /boot                   xfs     defaults        0 0
/dev/mapper/cl-home     /home                   xfs     defaults        0 0
/dev/mapper/cl-swap     swap                    swap    defaults        0 0
/dev/sdb1 /data2T ext4 defaults 0 0

分别注释三条记录

vi /etc/fstab
​
#/dev/mapper/cl-home     /home                   xfs     defaults        0 0
#/dev/mapper/cl-swap     swap                    swap    defaults        0 0
#/dev/sdb1 /data2T ext4 defaults 0 0

分别注释以下三条记录：发现 注释到 #/dev/mapper/cl-home /home 可以正常进系统，说明 /dev/mapper/cl-home需要修复

fsck -y /dev/mapper/cl-home
由于文件格式是xfs
xfs_repair /dev/mapper/cl-home (ext系列工具为fsck)
​
​
xfs_repair -L /dev/mapper/cl-home
​
如果修复失败，可以加上  -L  参数，这样可能会丢失部分数据。
​
​

先执行 xfs_repair -L /dev/mapper/cl-home

再执行xfs_repair /dev/mapper/cl-home

再执行xfs_check/dev/mapper/cl-home 检查文件系统是否修复成功。

说明：-L是修复xfs文件系统的最后手段，慎重选择，它会清空日志，会丢失用户数据和文件。

# xfs_repair /dev/mapper/cl-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.
ote that destroying the log may cause corruption -- please attempt a mount
of the filesystem before doing this.
​
​
​
xfs_repair -L /dev/mapper/cl-home
​
[root@centos7_loc6 ~]# xfs_repair -L /dev/mapper/cl-home
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...
        - found root inode c
Phase  - for each AG...
        - scan and clear agi unlinked lists...
        - process known inodes and perform inode discovery...
        - agno = 0
Metadata CRC error detected at xfs_dir_block block 0x7c26698/0x1000
bad directory block magic # 0 in block 0 for directory inode 10176945
corrupt block 0 in directory inode 10176945
        will junk block
no . entry for directory 10176945
no .. entry for directory 10176945
problem with directory contents in inode 10176945
cleared inode 10176945
        - agno = 1
        - agno = 2
        - agno = 
        - process newly discovered inodes...
Phase 4 - check for duplicate blocks...
        - setting up duplicate extent list...
        - check for inodes claiming duplicate blocks...
        - agno = 0
        - agno = 2
        - agno = 1
        - agno = 
entry "share" in shortform directory 11275604 references free inode 10176945
junking entry "share" in directory inode 11275604
entry ".." at block 0 offset 80 in directory inode 1127558550 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 10181109 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 1765985908 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 1765985941 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 1765986041 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 1765986497 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 1765987174 references free inode 10176945
entry ".." at block 0 offset 80 in directory inode 752128626 references free inode 10176945
Phase 5 - rebuild AG headers and trees...
        - reset superblock...
Phase 6 - check inode connectivity...
        - resetting contents of realtime bitmap and summary inodes
        - traversing filesystem ...
entry ".." in directory inode 10181109 points to free inode 10176945
bad hash table for directory inode 10181109 (no data entry): rebuilding
rebuilding directory inode 10181109
entry ".." in directory inode 752128626 points to free inode 10176945
bad hash table for directory inode 752128626 (no data entry): rebuilding
rebuilding directory inode 752128626
entry ".." in directory inode 1127558550 points to free inode 10176945
bad hash table for directory inode 1127558550 (no data entry): rebuilding
rebuilding directory inode 1127558550
entry ".." in directory inode 1765985908 points to free inode 10176945
bad hash table for directory inode 1765985908 (no data entry): rebuilding
rebuilding directory inode 1765985908
entry ".." in directory inode 1765985941 points to free inode 10176945
bad hash table for directory inode 1765985941 (no data entry): rebuilding
rebuilding directory inode 1765985941
entry ".." in directory inode 1765986041 points to free inode 10176945
bad hash table for directory inode 1765986041 (no data entry): rebuilding
rebuilding directory inode 1765986041
entry ".." in directory inode 1765986497 points to free inode 10176945
bad hash table for directory inode 1765986497 (no data entry): rebuilding
rebuilding directory inode 1765986497
entry ".." in directory inode 1765987174 points to free inode 10176945
bad hash table for directory inode 1765987174 (no data entry): rebuilding
rebuilding directory inode 1765987174
        - traversal finished ...
        - moving disconnected inodes to lost+found ...
disconnected dir inode 10176949, moving to lost+found
​
disconnected dir inode 1765987174, moving to lost+found
Phase 7 - verify and correct link counts...
resetting inode 276498 nlinks from 2 to 71
resetting inode 11275604 nlinks from 1 to 12
Maximum metadata LS (99:218728) is ahead of log (1:8).
Format log to cycle 102.
done

开机把挂载注释去掉

vim /etc/fstab
/dev/mapper/cl-home     /home                   xfs     defaults        0 0 

问题解决