Index: head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
===================================================================
--- head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
+++ head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/sys/zio.h
@@ -233,12 +233,11 @@
 };
 
 /*
- * We'll take the number 122 and 123 to indicate checksum errors and
- * fragmentation. Those doesn't collide with any errno values as they
- * are greater than ELAST.
+ * These are bespoke errnos used in ZFS. We map them to their closest FreeBSD
+ * equivalents. This gives us more useful error messages from strerror(3).
  */
-#define	ECKSUM	122
-#define	EFRAGS	123
+#define	ECKSUM	EINTEGRITY
+#define	EFRAGS	ENOSPC
 
 typedef void zio_done_func_t(zio_t *zio);