Problem with reporting of disk space

I ran out of room on a drive.  It was reporting that there was 0 space left on the drive.  I delete some files and then after running df -h it was still reporting 0 space left on drive.  I found this
http://serverfault.com/questions/158524/disk-space-not-freed-on-ext3-raid1-after-deleting
which explains quite nicely the problem.

In short the solution was to type

sudo tune2fs -m 0 /dev/<partitionname>

and all was solved.