From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752612AbaEUOjk (ORCPT ); Wed, 21 May 2014 10:39:40 -0400 Received: from mo4-p00-ob.smtp.rzone.de ([81.169.146.162]:24309 "EHLO mo4-p00-ob.smtp.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752047AbaEUOjh (ORCPT ); Wed, 21 May 2014 10:39:37 -0400 X-RZG-AUTH: :P2EQZWCpfu+qG7CngxMFH1J+yackYocTD1iAi8x+OWi/zfN1cLnBYfssBY9SQMKk8kCovkkmJbh+VP2spQG3tvMeGW7W X-RZG-CLASS-ID: mo00 From: Olaf Hering To: konrad.wilk@oracle.com Cc: xen-devel@lists.xen.org, linux-kernel@vger.kernel.org, david.vrabel@citrix.com, boris.ostrovsky@oracle.com, Olaf Hering Subject: [PATCH 3/3] xen/blkback: disable discard feature if requested by toolstack Date: Wed, 21 May 2014 16:32:42 +0200 Message-Id: <1400682762-17429-4-git-send-email-olaf@aepfle.de> X-Mailer: git-send-email 1.9.3 In-Reply-To: <1400682762-17429-1-git-send-email-olaf@aepfle.de> References: <1400682762-17429-1-git-send-email-olaf@aepfle.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Newer toolstacks may provide a boolean property "discard-enable" in the backend node. Its purpose is to disable discard for file backed storage to avoid fragmentation. Recognize this setting also for physical storage. If that property exists and is false, do not advertise "feature-discard" to the frontend. Signed-off-by: Olaf Hering --- drivers/block/xen-blkback/xenbus.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/block/xen-blkback/xenbus.c b/drivers/block/xen-blkback/xenbus.c index 9a547e6..a71ecf5 100644 --- a/drivers/block/xen-blkback/xenbus.c +++ b/drivers/block/xen-blkback/xenbus.c @@ -481,10 +481,15 @@ static void xen_blkbk_discard(struct xenbus_transaction xbt, struct backend_info struct xenbus_device *dev = be->dev; struct xen_blkif *blkif = be->blkif; int err; - int state = 0; + int state = 0, discard_enable; struct block_device *bdev = be->blkif->vbd.bdev; struct request_queue *q = bdev_get_queue(bdev); + err = xenbus_scanf(XBT_NIL, dev->nodename, "discard-enable", "%d", + &discard_enable); + if (err == 1 && !discard_enable) + return; + if (blk_queue_discard(q)) { err = xenbus_printf(xbt, dev->nodename, "discard-granularity", "%u",