[Qemu-devel] vpc size reporting problem

[Chun Yan Liu]

While testing with a 1GB VHD file created on win7, found that the VHD file
size reported on Windows is different from that is reported by qemu-img
info or within a Linux KVM guest.

Created a dynamic VHD file on win7, on Windows, it is reported 1024MB
(2097152 sectors). But with qemu-img info or within a Linux KVM guest,
it is reported 1023MB (2096640 sectors).

The values in the footer_buf are as follows:
creator_app: "win "
cylinders: 0x820 (2080)
heads: 0x10 (16)
cyl/sec: 0x3f (63)
current_size: 0x40000000 (1G)

So, if using current_size, it's correct; but using CHS will get a smaller size.

Should we add a check in this case and use "current_size" instead of
CHS?

BTW, before commit 0444dceee, there is a similar check for 'd2v',
if creator_app is 'd2v', using "size" instead of CHS. But in commit
0444dceee, this check is removed. To me, the new check and 'd2v'
check seem to be two different cases, why removing 'd2v' check?

Thanks,
Chunyan