From patchwork Mon Mar 4 14:02:32 2013 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Hajnoczi X-Patchwork-Id: 224725 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 70E8A2C02F9 for ; Tue, 5 Mar 2013 01:03:30 +1100 (EST) Received: from localhost ([::1]:34370 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCVzE-0004ZT-K6 for incoming@patchwork.ozlabs.org; Mon, 04 Mar 2013 09:03:28 -0500 Received: from eggs.gnu.org ([208.118.235.92]:40317) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCVyd-0004JF-2y for qemu-devel@nongnu.org; Mon, 04 Mar 2013 09:02:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UCVyW-00065s-Sb for qemu-devel@nongnu.org; Mon, 04 Mar 2013 09:02:51 -0500 Received: from mx1.redhat.com ([209.132.183.28]:5362) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UCVyW-00065k-Lk for qemu-devel@nongnu.org; Mon, 04 Mar 2013 09:02:44 -0500 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id r24E2iC5029467 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 4 Mar 2013 09:02:44 -0500 Received: from localhost (ovpn-112-24.ams2.redhat.com [10.36.112.24]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id r24E2gQG028153; Mon, 4 Mar 2013 09:02:43 -0500 From: Stefan Hajnoczi To: Date: Mon, 4 Mar 2013 15:02:32 +0100 Message-Id: <1362405755-3308-4-git-send-email-stefanha@redhat.com> In-Reply-To: <1362405755-3308-1-git-send-email-stefanha@redhat.com> References: <1362405755-3308-1-git-send-email-stefanha@redhat.com> X-Scanned-By: MIMEDefang 2.67 on 10.5.11.11 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x X-Received-From: 209.132.183.28 Cc: Kevin Wolf , Stefan Hajnoczi Subject: [Qemu-devel] [PATCH v2 3/6] qcow2: set L2 cache dependency in qcow2_alloc_bytes() X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Sender: qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org Compressed writes use qcow2_alloc_bytes() to allocate space with byte granularity. The affected clusters' refcounts will be incremented but we do not need to flush yet. Set a L2 cache dependency on the refcount block cache, so that the refcounts get written out before the L2 updates. Signed-off-by: Stefan Hajnoczi --- block/qcow2-refcount.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c index e8b5d0a..4d9df5f 100644 --- a/block/qcow2-refcount.c +++ b/block/qcow2-refcount.c @@ -669,7 +669,11 @@ int64_t qcow2_alloc_bytes(BlockDriverState *bs, int size) } } - bdrv_flush(bs->file); + /* The cluster refcount was incremented, either by qcow2_alloc_clusters() + * or explicitly by update_cluster_refcount(). Refcount blocks must be + * flushed before the caller's L2 table updates. + */ + qcow2_cache_set_dependency(bs, s->l2_table_cache, s->refcount_block_cache); return offset; }