From: Max Reitz <mre...@redhat.com>
In discard_single_l2(), we completely discard normal clusters instead of
simply turning them into preallocated zero clusters. That means we
should probably do the same with such preallocated zero clusters:
Discard them instead of keeping them allocated.
Reported-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Max Reitz <mre...@redhat.com>
Reviewed-by: Eric Blake <ebl...@redhat.com>
Signed-off-by: Kevin Wolf <kw...@redhat.com>
---
block/qcow2-cluster.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index fb91fd8..31077d8 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -1511,7 +1511,8 @@ static int discard_single_l2(BlockDriverState *bs,
uint64_t offset,
break;
case QCOW2_CLUSTER_ZERO:
- if (!full_discard) {
+ /* Preallocated zero clusters should be discarded in any case
*/
+ if (!full_discard && (old_l2_entry & L2E_OFFSET_MASK) == 0) {
continue;
}
break;
--
1.8.3.1
