Index: head/usr.sbin/makefs/mtree.c
===================================================================
--- head/usr.sbin/makefs/mtree.c
+++ head/usr.sbin/makefs/mtree.c
@@ -644,14 +644,17 @@
 				st->st_atime = num;
 				st->st_ctime = num;
 				st->st_mtime = num;
+#if HAVE_STRUCT_STAT_ST_MTIMENSEC
 				if (p == NULL)
 					break;
 				error = read_number(p, 10, &num, 0,
 				    INTMAX_MAX);
 				if (error)
 					break;
-				if (num != 0)
-					error = EINVAL;
+				st->st_atimensec = num;
+				st->st_ctimensec = num;
+				st->st_mtimensec = num;
+#endif
 			} else if (strcmp(keyword, "type") == 0) {
 				if (value == NULL) {
 					error = ENOATTR;
Index: head/usr.sbin/makefs/tests/makefs_tests_common.sh
===================================================================
--- head/usr.sbin/makefs/tests/makefs_tests_common.sh
+++ head/usr.sbin/makefs/tests/makefs_tests_common.sh
@@ -29,13 +29,7 @@
 
 KB=1024
 : ${TMPDIR=/tmp}
-# TODO: add mtree `time` support; get a lot of errors like this right now when
-# passing generating disk images with keyword mtree support, like:
-#
-# `[...]/mtree.spec:8: error: time: invalid value '1446458503'`
-#
-#DEFAULT_MTREE_KEYWORDS="type,mode,gid,uid,size,link,time"
-DEFAULT_MTREE_KEYWORDS="type,mode,gid,uid,size,link"
+DEFAULT_MTREE_KEYWORDS="type,mode,gid,uid,size,link,time"
 TEST_IMAGE="$TMPDIR/test.img"
 TEST_INPUTS_DIR="$TMPDIR/inputs"
 TEST_MD_DEVICE_FILE="$TMPDIR/md.output"