[XFS] Disable queue flag test in barrier check.

md raid1 can pass down barriers, but does not set an ordered flag on the
queue, so xfs does not even attempt a barrier write, and will never use
barriers on these block devices.

Remove the flag check and just let the barrier write test determine
barrier support.

A possible risk here is that if something does not set an ordered flag and
also does not properly return an error on a barrier write... but if it's
any consolation jbd/ext3/reiserfs never test the flag, and don't even do a
test write, they just disable barriers the first time an actual journal
barrier write fails.

SGI-PV: 983924

SGI-Modid: xfs-linux-melb:xfs-kern:31377a
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
Signed-off-by: Tim Shimmin <tes@sgi.com>
Signed-off-by: Lachlan McIlroy <lachlan@sgi.com>

fs/xfs/linux-2.6/xfs_super.c

@@ -746,14 +746,6 @@ xfs_mountfs_check_barriers(xfs_mount_t *mp)
 		return;
 	}
 
-	if (mp->m_ddev_targp->bt_bdev->bd_disk->queue->ordered ==
-					QUEUE_ORDERED_NONE) {
-		xfs_fs_cmn_err(CE_NOTE, mp,
-		  "Disabling barriers, not supported by the underlying device");
-		mp->m_flags &= ~XFS_MOUNT_BARRIER;
-		return;
-	}
-
 	if (xfs_readonly_buftarg(mp->m_ddev_targp)) {
 		xfs_fs_cmn_err(CE_NOTE, mp,
 		  "Disabling barriers, underlying device is readonly");