The command in the dual boot guide for cp -preserve for me doesn't work. All the instructions for the guide up until then works flawlessly. When i input that command it seems to be writing but while it's writing i see stuff like "cp: writing 'mnt/var/www/index.html': No space left on device"

The no space left on device is killing me. I don't know what the problem is. I followed the guide and everything seemed good up until then.