Processing MKDIR: unable to create directory 'AAA': read only file system

The problem is shown in the figure ：

df -h

cat /etc/fstab

Problem description

mkdir: cannot create directory `test': Read-only file system
mkdir:  Unable to create directory "kk":  Read only file system 

 But now he  /root , /opt , /apache  No files can be created under all folders 
 And execute reboot  Report a mistake ： Restart error ：Failed to open /dev/initctl: No such device or address

The final solution

reboot -f

 Think back to recent operations , I didn't do anything special , see history I didn't see any special operation .
 Chuan Shao ： You are /root  Can't create file under , Explain what you did before triggering its read-only protection , In general, you can restart it directly .

Using other blog methods has no effect , Maybe this whole path can't be created. It's special .
Reference resources ：
https://www.cnblogs.com/jxldjsn/p/11337990.html
https://www.cnblogs.com/pu20065226/p/11396175.html

other

I changed my job , I haven't had any blogs for more than a month . emmmm Take care of your blog later ~ During this period, I wrote N Multiple documents . Maybe write something kingbase Gold warehouse content