I recently resized/moved my home partition and then expanded my root partition into the free space remaining. I did this all off a bootable usb with gparted. When i started ubuntu back up and ran osm2pgsql(it converts map files into databse form) it complained about not having enough space in the root directory. Running all the usual df -h, gparted, gnome-disk, gnome-system-monitor and checking properties of my root directory showed that it has a capacity of 66.2GB, of which 6.0GB is used. When I use Disk Usage Analyzer though, it reports a size of ~6GB(which i guess is what osm2pgsql detects too). The strange thing is that I didn't even start with 6GB before i resized/moved. I started with about 12GB if my memory serves correctly. Also, my home partition is reported to have shrunk to 64.1GB from about 1.4TB before when using Disk Usage Analyzer. As a final clue, disk Usage Analyzer reports the correct size of root before it scans the folders - not sure if that helps.