From patchwork Mon Sep 13 12:42:48 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 64599 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [199.232.76.165]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 1705AB6F11 for ; Mon, 13 Sep 2010 23:04:41 +1000 (EST) Received: from localhost ([127.0.0.1]:56443 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Ov8i6-00066y-BR for incoming@patchwork.ozlabs.org; Mon, 13 Sep 2010 09:04:38 -0400 Received: from [140.186.70.92] (port=55335 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1Ov8N6-0000Fb-Iq for qemu-devel@nongnu.org; Mon, 13 Sep 2010 08:43:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1Ov8N5-0004MS-55 for qemu-devel@nongnu.org; Mon, 13 Sep 2010 08:42:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:10765) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1Ov8N4-0004ML-Ri for qemu-devel@nongnu.org; Mon, 13 Sep 2010 08:42:55 -0400 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o8DCgqEQ014221 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Mon, 13 Sep 2010 08:42:53 -0400 Received: from dhcp-5-188.str.redhat.com (vpn2-9-36.ams2.redhat.com [10.36.9.36]) by int-mx02.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o8DCgUmO027971; Mon, 13 Sep 2010 08:42:51 -0400 From: Kevin Wolf To: anthony@codemonkey.ws Date: Mon, 13 Sep 2010 14:42:48 +0200 Message-Id: <1284381771-7333-11-git-send-email-kwolf@redhat.com> In-Reply-To: <1284381771-7333-1-git-send-email-kwolf@redhat.com> References: <1284381771-7333-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.12 X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. Cc: kwolf@redhat.com, qemu-devel@nongnu.org Subject: [Qemu-devel] [STABLE 0.13][PATCH 10/13] qcow2: Remove unnecessary flush after L2 write X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org When a new cluster was allocated, we only need a flush after the write to the L2 table if it was a COW and we need to decrease the refcounts of the old clusters. Signed-off-by: Kevin Wolf (cherry picked from commit 7ec5e6a4ca43494949465f9f9f3d9e4c7c620503) --- block/qcow2-cluster.c | 16 ++++++++++++---- 1 files changed, 12 insertions(+), 4 deletions(-) diff --git a/block/qcow2-cluster.c b/block/qcow2-cluster.c index 166922f..f562b16 100644 --- a/block/qcow2-cluster.c +++ b/block/qcow2-cluster.c @@ -655,7 +655,7 @@ static int write_l2_entries(BlockDriverState *bs, uint64_t *l2_table, int ret; BLKDBG_EVENT(bs->file, BLKDBG_L2_UPDATE); - ret = bdrv_pwrite_sync(bs->file, l2_offset + start_offset, + ret = bdrv_pwrite(bs->file, l2_offset + start_offset, &l2_table[l2_start_index], len); if (ret < 0) { return ret; @@ -718,9 +718,17 @@ int qcow2_alloc_cluster_link_l2(BlockDriverState *bs, QCowL2Meta *m) goto err; } - for (i = 0; i < j; i++) - qcow2_free_any_clusters(bs, - be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); + /* + * If this was a COW, we need to decrease the refcount of the old cluster. + * Also flush bs->file to get the right order for L2 and refcount update. + */ + if (j != 0) { + bdrv_flush(bs->file); + for (i = 0; i < j; i++) { + qcow2_free_any_clusters(bs, + be64_to_cpu(old_cluster[i]) & ~QCOW_OFLAG_COPIED, 1); + } + } ret = 0; err: