From patchwork Mon Sep 21 14:30:49 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 11789955 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id D77056CB for ; Mon, 21 Sep 2020 14:33:25 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 296F021D95 for ; Mon, 21 Sep 2020 14:33:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=igalia.com header.i=@igalia.com header.b="L7gh9t7P" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 296F021D95 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=igalia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Received: from localhost ([::1]:37394 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kKMse-0005En-8X for patchwork-qemu-devel@patchwork.kernel.org; Mon, 21 Sep 2020 10:33:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47788) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kKMqZ-0003g3-I6; Mon, 21 Sep 2020 10:31:15 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:47069) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kKMqU-000485-Qd; Mon, 21 Sep 2020 10:31:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=igalia.com; s=20170329; h=Content-Transfer-Encoding:MIME-Version:References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From; bh=Tw8Cc9SW+/2F9odwf3t7puTe414oOegZOiua3UDi2nU=; b=L7gh9t7P9WP/9i9d5cnBCEP+oOtHRiXeSr8cdS31cHx8iM6aFGk1JfrogdX6tp9R6rTZAJD0RZ3NMpbwPpuX9QGE7B2mcTXN1YAPXCV1G61tnl4MkP4DicK8/J1wurrROIIPrkL3MJ4YrqfYhLxP6Ge/rCdqYqaZspBYfuB6HPTyCJFP1pMYr4ebIlpzFt6fh4zqlni/4CNCrpy7oskCIntkKyXQ+ZlGlOabp/NWrGtpOybZBnw1E9MRKuRRlOKbRyt5gpJ/GmGGvBwBXuQbghaYFyjtdn3Ume97f9A+j2AIr6/i9ZxSSPFA6G4GlJWZyrxfX/OHOQMj6wWJpzx3Tw==; Received: from [81.0.34.134] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1kKMqQ-0000Wf-9Z; Mon, 21 Sep 2020 16:31:06 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1kKMqD-0005yV-3j; Mon, 21 Sep 2020 16:30:53 +0200 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v4 1/2] qcow2: Report BDRV_BLOCK_ZERO more accurately in bdrv_co_block_status() Date: Mon, 21 Sep 2020 16:30:49 +0200 Message-Id: X-Mailer: git-send-email 2.20.1 In-Reply-To: References: MIME-Version: 1.0 Received-SPF: pass client-ip=178.60.130.6; envelope-from=berto@igalia.com; helo=fanzine.igalia.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/21 10:31:07 X-ACL-Warn: Detected OS = Linux 2.2.x-3.x (no timestamps) [generic] [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Alberto Garcia , qemu-block@nongnu.org, Max Reitz Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" If a BlockDriverState supports backing files but has none then any unallocated area reads back as zeroes. bdrv_co_block_status() is only reporting this is if want_zero is true, but this is an inexpensive test and there is no reason not to do it in all cases. Suggested-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Alberto Garcia Reviewed-by: Vladimir Sementsov-Ogievskiy --- block/io.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/block/io.c b/block/io.c index a2389bb38c..ef1ea806e8 100644 --- a/block/io.c +++ b/block/io.c @@ -2391,17 +2391,17 @@ static int coroutine_fn bdrv_co_block_status(BlockDriverState *bs, if (ret & (BDRV_BLOCK_DATA | BDRV_BLOCK_ZERO)) { ret |= BDRV_BLOCK_ALLOCATED; - } else if (want_zero && bs->drv->supports_backing) { + } else if (bs->drv->supports_backing) { BlockDriverState *cow_bs = bdrv_cow_bs(bs); - if (cow_bs) { + if (!cow_bs) { + ret |= BDRV_BLOCK_ZERO; + } else if (want_zero) { int64_t size2 = bdrv_getlength(cow_bs); if (size2 >= 0 && offset >= size2) { ret |= BDRV_BLOCK_ZERO; } - } else { - ret |= BDRV_BLOCK_ZERO; } }