I've encountered this issue. I have a VM with Debian 8 on it. I gave that disk 350gb, /dev/sda1 is 344gb, used is 330gb and it's 100%. Situation is as follows, I'm importing huge mysql dump (300gb in single file) and it's still running (i.e. it wasn't interrupted due to reaching the limit). When it hit 0, I moved some tables and and index files of some tables to the host (~170gb) but system didn't reflect that and still says that it's 100% used. Question is, what can I do about it without anyhow interrupting that import so that it can finish up when there's more space?
Incorrect used/free space
debian;filesystems