On 28.06.20 13:02, Alberto Garcia wrote: > Traditional qcow2 images don't allow preallocation if a backing file > is set. This is because once a cluster is allocated there is no way to > tell that its data should be read from the backing file. > > Extended L2 entries have individual allocation bits for each > subcluster, and therefore it is perfectly possible to have an > allocated cluster with all its subclusters unallocated. > > Signed-off-by: Alberto Garcia <be...@igalia.com> > Reviewed-by: Eric Blake <ebl...@redhat.com> > --- > block/qcow2.c | 7 ++++--- > tests/qemu-iotests/206.out | 2 +- > 2 files changed, 5 insertions(+), 4 deletions(-)
Reviewed-by: Max Reitz <mre...@redhat.com>
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