QCowHeader and QCowExtension are structs that reside in the on-disk
image format, and are read and written directly via bdrv_pread()/write(),
and as such should be packed to avoid any unintentional struct padding.
Signed-off-by: NJeff Cody <jcody@redhat.com>
Reviewed-by: NRichard Henderson <rth@twiddle.net>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>