On 05/22/2014 03:42 AM, Stefan Hajnoczi wrote: > Normally one would expect that qcow2 image file lengths are multiples of > the cluster size. This is not true in all cases and the spec should > document this so implementers remember to accept such files. > > $ qemu-img create -f qcow2 foo.qcow2 2G > Formatting 'foo.qcow2', fmt=qcow2 size=2147483648 encryption=off > cluster_size=65536 lazy_refcounts=off > $ ls -l foo.qcow2 > -rw-r--r-- 1 stefanha stefanha 197120 May 22 11:40 foo.qcow2 > $ bc -q > 3 * (64 * 1024) + 512 > 197120 > > The extra sector are the 4 L1 table entries that a 2 GB disk with 64 KB > cluster size needs. The rest of the L1 table is omitted from the file > but allocation will continue at the next cluster boundary. > > Reported-by: Maria Kustova <m...@catit.be> > Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com> > --- > docs/specs/qcow2.txt | 4 ++++ > 1 file changed, 4 insertions(+)
Reviewed-by: Eric Blake <ebl...@redhat.com> -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org
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