Index: sbin/fsck_ffs/pass2.c
===================================================================
--- sbin/fsck_ffs/pass2.c
+++ sbin/fsck_ffs/pass2.c
@@ -665,7 +665,13 @@
 static int
 blksort(const void *arg1, const void *arg2)
 {
+	struct inoinfo * const *in1;
+	struct inoinfo * const *in2;
 
-	return ((*(struct inoinfo * const *)arg1)->i_blks[0] -
-		(*(struct inoinfo * const *)arg2)->i_blks[0]);
+	in1 = arg1;
+	in2 = arg2;
+	if ((*in1)->i_isize == 0 || (*in2)->i_isize == 0)
+		return ((*in1)->i_isize - (*in2)->i_isize);
+
+	return ((*in1)->i_blks[0] - (*in2)->i_blks[0]);
 }