I'm not sure how it did, but I am running into file names with a real slash, the one used for directory tree delimiter. Nothing can access it or modify it. I'm not able to do anything with it, not even removing it. Is it possible to simply rename it to a regular name so that I won't lose anything important? Or do I have to delete it?  root@ubuntu:~/e # ls -l-????????? ? ? ? ? ? az/?_root@ubuntu:~/e # echo $?1Ubuntu 16.04.1, ext4  By curiosity, what should I do if my disk gets corrupted again and brings up files named . (one single dot, current directory) or .. (two dots, parent dir)?  
Slash appeared on file name
linux;filesystems