I just partitioned a 500GB HDD 50%-50%. I installed ubuntu 11.10 on one half and copied a load of files onto the other. When I don't mount the other partition, it shows I have used 12.1GB and have about 240GB free. The second I mount the other partition, I can't copy any files over and get a disk full message. There is about 10-20GB Free on the other partition. Am I doing something wrong or is this a bug?