Index: head/sbin/mount/mount.c
===================================================================
--- head/sbin/mount/mount.c
+++ head/sbin/mount/mount.c
@@ -485,10 +485,18 @@
 		strlcpy(realfsfile, fs->fs_file, sizeof(realfsfile));
 	}
 
+	/* 
+	 * Consider the filesystem to be mounted if:
+	 * It has the same mountpoint as a mounted filesytem, and
+	 * It has the same type as that same mounted filesystem, and
+	 * It has the same device name as that same mounted filesystem, OR
+	 *     It is a nonremountable filesystem
+	 */
 	for (i = mntsize - 1; i >= 0; --i)
 		if (strcmp(realfsfile, mntbuf[i].f_mntonname) == 0 &&
+		    strcmp(fs->fs_vfstype, mntbuf[i].f_fstypename) == 0 && 
 		    (!isremountable(fs->fs_vfstype) ||
-		     strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0))
+		     (strcmp(fs->fs_spec, mntbuf[i].f_mntfromname) == 0)))
 			return (1);
 	return (0);
 }