--- a/usr/src/uts/common/sys/fs/zfs.h	Thu Jan 07 21:27:35 2010 +0100
+++ b/usr/src/uts/common/sys/fs/zfs.h	Thu Jan 07 13:33:12 2010 -0700
@@ -652,6 +652,7 @@
 #define	ZVOL_FULL_RDEV_DIR	ZVOL_DIR "/rdsk/"
 
 #define	ZVOL_PROP_NAME		"name"
+#define	ZVOL_DEFAULT_BLOCKSIZE	8192
 
 /*
  * /dev/zfs ioctl numbers.