diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c
index 9269ddaefd2dde4c5e6be38baa9cab12a7c083bb..fde397e8aa4a30dcddfca613e31ffd155e2c190c 100644
--- a/block/qcow2-cluster.c
+++ b/block/qcow2-cluster.c
@@ -381,10 +381,10 @@ static int copy_sectors(BlockDriverState *bs, uint64_t start_sect,
  * For a given offset of the disk image, find the cluster offset in
  * qcow2 file. The offset is stored in *cluster_offset.
  *
- * on entry, *num is the number of contiguous clusters we'd like to
+ * on entry, *num is the number of contiguous sectors we'd like to
  * access following offset.
  *
- * on exit, *num is the number of contiguous clusters we can read.
+ * on exit, *num is the number of contiguous sectors we can read.
  *
  * Return 0, if the offset is found
  * Return -errno, otherwise.