How can I solve linux system faults?

For troubleshooting linux system faults, let's take a look at the urgent-Linux general technology-Linux technology and application information. The following is a detailed description. Linux cannot be started now, so I will not go down here. As the younger brother is unfamiliar with the linux system, please kindly inform me of the detailed methods and do not consider re-deploying the system, thank you.
Can't create lock file/etc/mtab ~ 468: no space left on device (use-n flag to override)
Can't create lock file/etc/mtab ~ 469: no space left on device (use-n flag to override)
Can't create lock file/etc/mtab ~ 470: no space left on device (use-n flag to override)
Can't create lock file/etc/mtab ~ 471: no space left on device (use-n flag to override)

Finding module dependencies:
Cannot create temp file/tmp/devlabel. p0meqw
/Sbin/devlabel: line 893: $ temp_proc: ambiguous redirect