From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:43068) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cHKCB-00045f-Sv for qemu-devel@nongnu.org; Wed, 14 Dec 2016 19:46:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cHKC9-0001Wo-9H for qemu-devel@nongnu.org; Wed, 14 Dec 2016 19:46:51 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:44829) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cHKC8-0001Vy-V5 for qemu-devel@nongnu.org; Wed, 14 Dec 2016 19:46:49 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.17/8.16.0.17) with SMTP id uBF0haKn056464 for ; Wed, 14 Dec 2016 19:46:47 -0500 Received: from e38.co.us.ibm.com (e38.co.us.ibm.com [32.97.110.159]) by mx0a-001b2d01.pphosted.com with ESMTP id 27bdm90wk4-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 14 Dec 2016 19:46:47 -0500 Received: from localhost by e38.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 14 Dec 2016 17:46:47 -0700 From: Michael Roth Date: Wed, 14 Dec 2016 18:44:44 -0600 In-Reply-To: <1481762701-4587-1-git-send-email-mdroth@linux.vnet.ibm.com> References: <1481762701-4587-1-git-send-email-mdroth@linux.vnet.ibm.com> Message-Id: <1481762701-4587-51-git-send-email-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 50/67] qcow2: Inform block layer about discard boundaries List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-stable@nongnu.org, Eric Blake , Kevin Wolf From: Eric Blake At the qcow2 layer, discard is only possible on a per-cluster basis; at the moment, qcow2 silently rounds any unaligned requests to this granularity. However, an upcoming patch will fix a regression in the block layer ignoring too much of an unaligned discard request, by changing the block layer to break up a discard request at alignment boundaries; for that to work, the block layer must know about our limits. However, we can't go one step further by changing qcow2_discard_clusters() to assert that requests are always aligned, since that helper function is reached on paths outside of the block layer. CC: qemu-stable@nongnu.org Signed-off-by: Eric Blake Reviewed-by: Max Reitz Signed-off-by: Kevin Wolf (cherry picked from commit ecdbead659f037dc572bba9eb1cd31a5a1a9ad9a) Signed-off-by: Michael Roth --- block/qcow2.c | 1 + 1 file changed, 1 insertion(+) diff --git a/block/qcow2.c b/block/qcow2.c index 91ef4df..497df0f 100644 --- a/block/qcow2.c +++ b/block/qcow2.c @@ -1204,6 +1204,7 @@ static void qcow2_refresh_limits(BlockDriverState *bs, Error **errp) bs->bl.request_alignment = BDRV_SECTOR_SIZE; } bs->bl.pwrite_zeroes_alignment = s->cluster_size; + bs->bl.pdiscard_alignment = s->cluster_size; } static int qcow2_set_key(BlockDriverState *bs, const char *key) -- 1.9.1