From mboxrd@z Thu Jan  1 00:00:00 1970
From: Christoph Hellwig <hch@infradead.org>
Subject: [PATCH 10/15] ext4: do not send discards as barriers
Date: Wed, 18 Aug 2010 05:29:18 -0400
Message-ID: <20100818093501.533010053@bombadil.infradead.org>
References: <20100818093432.646633424@bombadil.infradead.org>
Cc: chris.mason@oracle.com, swhiteho@redhat.com,
	konishi.ryusuke@lab.ntt.co.jp, tytso@mit.edu, jack@suse.cz,
	hirofumi@mail.parknet.co.jp, mfasheh@suse.com,
	joel.becker@oracle.com, hughd@google.com,
	linux-fsdevel@vger.kernel.org
To: tj@kernel.org
Return-path: <linux-fsdevel-owner@vger.kernel.org>
Received: from bombadil.infradead.org ([18.85.46.34]:48835 "EHLO
	bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1752584Ab0HRJfg (ORCPT
	<rfc822;linux-fsdevel@vger.kernel.org>);
	Wed, 18 Aug 2010 05:35:36 -0400
Content-Disposition: inline; filename=ext4-discard-nobarrier
Sender: linux-fsdevel-owner@vger.kernel.org
List-ID: <linux-fsdevel.vger.kernel.org>

ext4 already uses synchronous discards, no need to add I/O barriers.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/ext4/mballoc.c
===================================================================
--- linux-2.6.orig/fs/ext4/mballoc.c	2010-08-17 16:48:50.546274081 +0200
+++ linux-2.6/fs/ext4/mballoc.c	2010-08-17 16:48:58.896006097 +0200
@@ -2589,9 +2589,7 @@ static void release_blocks_on_commit(jou
 					(unsigned long long)discard_block,
 					entry->count);
 			ret = sb_issue_discard(sb, discard_block, entry->count,
-						GFP_NOFS,
-						BLKDEV_IFL_WAIT |
-						BLKDEV_IFL_BARRIER);
+						GFP_NOFS, BLKDEV_IFL_WAIT);
 			if (ret == EOPNOTSUPP) {
 				ext4_warning(sb,
 					"discard not supported, disabling");