Comment 31 for bug 1022901

I have copied all of the content of the guest machine, deleted the image ubuntu-pdc-vdb.img and created a new one without "fallocate", but only with preallocation=metadata. The problem is that the image is growing progressively and has obviously no limit, although I gave it one. The root filesystem's image is the same case:

qemu-img info ubuntu-pdc-vda.img
image: ubuntu-pdc-vda.img
file format: qcow2
virtual size: 10G (10737418240 bytes)
disk size: 14G
cluster_size: 65536

and for confirmation:
du -sh ubuntu-pdc-vda.img
15G ubuntu-pdc-vda.img

I made a test and saw that when I delete something from the guest, the real size of the image is not decreasing (I read it is normal). OK, but when I write something again, it doesn't use the freed space, but instead grows the image. So for example:
1. The initial physical size of the image is 1GB.
2. I copy 1GB of data in the guest. It's physical size becomes 2GB.
3. I delete this data (1GB). The physical size of the image remains 2GB.
4. I copy another 1GB of data to the guest.
5. The physical size of the image becomes 3GB.
6. And so on with no limit. It doesn't care if the virtual size is less.

Is this normal - the real/physical size of the image to be larger than the virtual limit???