Am 11.02.2015 um 23:32 hat Max Reitz geschrieben: > On 2015-02-11 at 11:22, Kevin Wolf wrote: > > If total_sectors is rounded to match the geometry, total_size needs to > be changed as well. Otherwise we end up with an image whose geometry > describes a disk larger than the image file, which doesn't end well. > > Signed-off-by: Kevin Wolf <kw...@redhat.com> > --- > block/vpc.c | 10 +++------- > 1 file changed, 3 insertions(+), 7 deletions(-) > > > Looks fine to me, but the spec says: "When the user creates a hard disk of a > certain size, the size of the hard disk image in the virtual machine is > smaller > than that created by the user. This is because CHS value calculated from the > hard disk size is rounded down." > > So, well, qemu has been violating the specification all along, I guess.
Initially we rounded the size down. This ended up truncating images during qemu-img convert, so it was decided that rounding up is the less bad solution. > So, with that in mind (that nobody has been screaming so far): > > Reviewed-by: Max Reitz <mre...@redhat.com> Thanks! > Alternatively we may want to "fix" it, and actually let the CHS size be > smaller > than total_sectors/total_size, if that's possible. But maybe that'll be even > worse, so I'm fine either way. That's possible. With VHD, however, I wouldn't make any such changes without proof that some software needs it and other software isn't affected. This is all pretty fragile. Kevin
