This is happened because the electricity in my city is black out. When I start my laptop, it show the bootloader option but after I pressed enter, the system can not boot into the operating system. It is said that it can not mount sda.
I try to access it using the boot operating system through my flash disk, but I can’t mount the sda.
After I read in ubuntuforum, I try this command.
sudo e2fsck -f -b 32768 -y /dev/sda1
After It done doing some processing, I reboot and the system back to normal