Index: usr.sbin/makefs/makefs.8
===================================================================
--- usr.sbin/makefs/makefs.8
+++ usr.sbin/makefs/makefs.8
@@ -53,7 +53,7 @@
 .Op Fl m Ar maximum-size
 .Op Fl N Ar userdb-dir
 .Op Fl o Ar fs-options
-.Op Fl r Ar roundup
+.Op Fl R Ar roundup-size
 .Op Fl S Ar sector-size
 .Op Fl s Ar image-size
 .Op Fl t Ar fs-type
@@ -196,9 +196,14 @@
 See the
 .Fl Z
 flag.
-.It Fl r Ar roundup
-Round the image up to specified block size that should be multiple
-of block size.
+.It Fl R Ar roundup-size
+Round the image up to
+.Ar roundup-size .
+.Ar roundup-size
+should be a multiple of the file system block size.
+This option only applies to the
+.Sy ffs
+file system type.
 .It Fl S Ar sector-size
 Set the file system sector size to
 .Ar sector-size .
Index: usr.sbin/makefs/makefs.c
===================================================================
--- usr.sbin/makefs/makefs.c
+++ usr.sbin/makefs/makefs.c
@@ -209,10 +209,10 @@
 			fsoptions.sparse = 1;
 			break;
 
-		case 'r':
+		case 'R':
 			/* Round image size up to specified block size */
 			fsoptions.roundup =
-			    strsuftoll("roundup", optarg, 0, LLONG_MAX);
+			    strsuftoll("roundup-size", optarg, 0, LLONG_MAX);
 			break;
 
 		case 's':
@@ -365,7 +365,7 @@
 	prog = getprogname();
 	fprintf(stderr,
 "usage: %s [-t fs-type] [-o fs-options] [-d debug-mask] [-B endian]\n"
-"\t[-S sector-size] [-M minimum-size] [-m maximum-size] [-r roundup ]\n"
+"\t[-S sector-size] [-M minimum-size] [-m maximum-size] [-R roundup-size]\n"
 "\t[-s image-size] [-b free-blocks] [-f free-files] [-F mtree-specfile]\n"
 "\t[-xZ] [-N userdb-dir] image-file directory | manifest [extra-directory ...]\n",
 	    prog);