Seems like it would be more useful to just poll regularly and notify on space running out.
Otherwise you´ll just have a server completely filled up ALSO with an 8Gb blank file on it you still can´t SSH to.
If your distro doesn’t let you SSH in when the disk is full, you need to get another distro. I’ve filled up my disk on Ubuntu and Debian many times, and have never had trouble logging in with SSH.
I wrote the author but posting here for completeness, I used to dual boot meego alongside sailfish on my Nokia N9.
So it should still be possible, dig around on XDA-devs for tutorials.