linux操作系统未正常启动提示"Entering emergency mode. Exit the shell to continue"

是一台阿里云ecs服务器，通过vnc登录看到如下信息，进入了救援模式：
Generating “/run/initramfs/rdsosreport.txt”
“Entering emergency mode. Exit the shell to continue”
“Type ‘journalctl’ to view system log.”
You might want to save “/run/initramfs/rdsosreport.txt” to a USB stick or /boot after mounting them and attach it to a bug report.

journalctl提示/dev/vda1 contains a file system with errors,check forced
fsck failed with error code 4.
Failed to start FIle System Check on /dev/disk/by-uuid/xxx
Dependency failed for /sysroot.
等很多错误，无法看到操作系统启动到哪个地方进入的救援模式！

1、在:/#下执行fsck -y /dev/vda1，有fsck命令，提示/dev/vda1 is mounted

2、将该目录umount掉，再次重启就可以正常进入系统