--- b/sys/fs/msdosfs/msdosfs_vfsops.c	
+++ b/sys/fs/msdosfs/msdosfs_vfsops.c	
@@ -163,14 +163,14 @@ update_mp(struct mount *mp, struct thread *td)
 		pmp->pm_mask = v & ALLPERMS;
 	if (vfs_scanopt(mp->mnt_optnew, "dirmask", "%d", &v) == 1)
 		pmp->pm_dirmask = v & ALLPERMS;
-	vfs_flagopt(mp->mnt_optnew, "shortname",
-	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
-	vfs_flagopt(mp->mnt_optnew, "shortnames",
-	    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
-	vfs_flagopt(mp->mnt_optnew, "longname",
-	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
-	vfs_flagopt(mp->mnt_optnew, "longnames",
-	    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
+	if (!vfs_flagopt(mp->mnt_optnew, "shortname",
+		 &pmp->pm_flags, MSDOSFSMNT_SHORTNAME))
+		vfs_flagopt(mp->mnt_optnew, "shortnames",
+		    &pmp->pm_flags, MSDOSFSMNT_SHORTNAME);
+	if (!vfs_flagopt(mp->mnt_optnew, "longname",
+		 &pmp->pm_flags, MSDOSFSMNT_LONGNAME))
+		vfs_flagopt(mp->mnt_optnew, "longnames",
+		    &pmp->pm_flags, MSDOSFSMNT_LONGNAME);
 	vfs_flagopt(mp->mnt_optnew, "kiconv",
 	    &pmp->pm_flags, MSDOSFSMNT_KICONV);
 
--