I want to force a fsck after an Instance reboot, you can check more details on cyberciti.biz website.

Check if you have this line.

~# cat /etc/init/mountall.conf | grep "/forcefsck"

    [ -f /forcefsck ] && force_fsck="--force-fsck"

Create this file

~# touch /forcefsck

And reboot

~# reboot