diff --git a/include/sys/spa.h b/include/sys/spa.h
index e5ec39b64dc..e0eed831d30 100644
--- a/include/sys/spa.h
+++ b/include/sys/spa.h
@@ -190,11 +190,11 @@ typedef struct zio_cksum_salt {
  *
  *	64	56	48	40	32	24	16	8	0
  *	+-------+-------+-------+-------+-------+-------+-------+-------+
- * 0	|		vdev1		| pad   |	  ASIZE		|
+ * 0	|  pad  |	  vdev1         | pad   |	  ASIZE		|
  *	+-------+-------+-------+-------+-------+-------+-------+-------+
  * 1	|G|			 offset1				|
  *	+-------+-------+-------+-------+-------+-------+-------+-------+
- * 2	|		vdev2		| pad   |	  ASIZE		|
+ * 2	|  pad  |	  vdev2         | pad   |	  ASIZE		|
  *	+-------+-------+-------+-------+-------+-------+-------+-------+
  * 3	|G|			 offset2				|
  *	+-------+-------+-------+-------+-------+-------+-------+-------+