Index: usr.sbin/makefs/ffs.c
===================================================================
--- usr.sbin/makefs/ffs.c
+++ usr.sbin/makefs/ffs.c
@@ -623,12 +623,19 @@
 		    e, tmpdir.d_namlen, this, curdirsize);		\
 } while (0);
 
-	/*
-	 * XXX	this needs to take into account extra space consumed
-	 *	by indirect blocks, etc.
-	 */
 #define	ADDSIZE(x) do {							\
-	fsopts->size += roundup((x), ffs_opts->fsize);			\
+	if ((x) < UFS_NDADDR * ffs_opts->bsize) {			\
+		fsopts->size += roundup((x), ffs_opts->fsize);		\
+	} else {							\
+		/* Count space consumed by indirecttion blocks. */	\
+		fsopts->size +=	ffs_opts->bsize *			\
+		    (howmany((x), UFS_NDADDR * ffs_opts->bsize) - 1);	\
+		/*							\
+		 * If the file is big enough to use indirect blocks,	\
+		 * we allocate bsize block for trailing data.		\
+		 */							\
+		fsopts->size += roundup((x), ffs_opts->bsize);		\
+	}								\
 } while (0);
 
 	curdirsize = 0;