From mboxrd@z Thu Jan 1 00:00:00 1970 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 From: Stefan Hajnoczi 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> Subject: [Qemu-devel] [PATCH v2 3/6] qcow2: set L2 cache dependency in qcow2_alloc_bytes() List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Kevin Wolf , Stefan Hajnoczi 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; } -- 1.8.1.4