Mounting disk/file into ling

I wanted to know if I can mount disk or files into LING VM and read & write to them ?

I tried mounting by specifying the disk = ['file:/tmp/file.dat,hda,rw'] or disk = ['phy:/dev/sda3,hda,rw'] in the domain_config but I am not sure how to check if it worked and how to create files onto it ?
I know that I will need to use 9p to achieve the read write part but not sure how to access the disk ?