Why do you first luksClose root_fs, then mkdir a directory, and then luksOpen root_fs again?
Seems superfluous.
The name you pick, in your case root_fs must be in line with the entires in fstab and crypttab, both in etc
I think.
Just thinking out loud, rather asking then telling.
Thanks too.
You might wanna add your how-to here:
cryptsetup-t195.htmlif you like.