Don't set relatime when noatime is specified

Since commit 0a1c01c9477602ee8b44548a9405b2c1d587b5a2 ("Make relatime
default") when a file system is mounted explicitely with noatime it gets
both the MNT_RELATIME and MNT_NOATIME bits set.

This shows up like this in /proc/mounts:

  /dev/xxx /yyy ext3 rw,noatime,relatime,errors=continue,data=writeback 0 0

That looks strange.  The VFS uses noatime in this case, but both flags
are set.  So it's more a cosmetic issue, but still better to fix.

Cc: mjg@redhat.com
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

fs/namespace.c

@@ -1920,8 +1920,9 @@ long do_mount(char *dev_name, char *dir_name, char *type_page,
 	if (data_page)
 		((char *)data_page)[PAGE_SIZE - 1] = 0;
 
-	/* Default to relatime */
-	mnt_flags |= MNT_RELATIME;
+	/* Default to relatime unless overriden */
+	if (!(flags & MS_NOATIME))
+		mnt_flags |= MNT_RELATIME;
 
 	/* Separate the per-mountpoint flags */
 	if (flags & MS_NOSUID)