You mean ext4. Your filesystem is broken, either by software or hardware. However, please describe the crash symptoms. Are there any error messages? The system just stops? What are the circumstances when it stops?
Steps you can take:
- check the filesystem with e2fsck. If the computer can't be booted, boot from live media and run the file system checker from there. If the checker is successful, try booting from the disk again.
- simply reinstall. If the problem is not caused by hardware, it will go away.
In both cases, it might be a good idea to think what could have caused this. Did you run any unusual programs? Could you have created an invalid disk layout during installation?
- if you suspect that hardware is the cause, check the SSD. I don't have a good suggestion for that, but in my experience, the internet knows such things.