1 files changed, 5 insertions, 0 deletions
diff --git a/block/qcow2.c b/block/qcow2.c
index e22f6dc..7cfcd84 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -2491,6 +2491,11 @@ static coroutine_fn int qcow2_co_pdiscard(BlockDriverState *bs,
     int ret;
     BDRVQcow2State *s = bs->opaque;
 
+    if (!QEMU_IS_ALIGNED(offset | count, s->cluster_size)) {
+        assert(count < s->cluster_size);
+        return -ENOTSUP;
+    }
+
     qemu_co_mutex_lock(&s->lock);
     ret = qcow2_discard_clusters(bs, offset, count >> BDRV_SECTOR_BITS,
                                  QCOW2_DISCARD_REQUEST, false);