From patchwork Thu Sep 10 17:46:01 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alberto Garcia X-Patchwork-Id: 274019 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH, MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0982BC43461 for ; Thu, 10 Sep 2020 17:48:23 +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 762F2206BE for ; Thu, 10 Sep 2020 17:48:22 +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="mK5BgWou" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 762F2206BE 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+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:35154 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kGQgH-00085K-G3 for qemu-devel@archiver.kernel.org; Thu, 10 Sep 2020 13:48:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:46650) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kGQer-0005Zr-EV; Thu, 10 Sep 2020 13:46:53 -0400 Received: from fanzine.igalia.com ([178.60.130.6]:46657) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kGQep-0004TJ-4Q; Thu, 10 Sep 2020 13:46:53 -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=CCQk4gxUq9a7nkIZ5yTEM8VEAw+njngKoOhqkpjyAFQ=; b=mK5BgWou8XwBqWd7YoGIYaHGcCyKLrcqtcg+e6N3xhCQKZPt1+TrkNnbLVTiiwQF0LHpnd5CHftsuoZs9BsNFL9CWOqEtp5nlyDaRfqPbfqz7QJj4ajC49YEcUx5xBg2JPLS5Fbfe4CryOOJ/zcusOLccaJzBDzPJIhV7DbH9YkMtUhB+/Rxv/NX5JocE+jCAtavqhq/I+1Nv51hwiM7EsETPT9tj0naA4fPHwIkzN/RSfeUdWxi8YLnsWDibbupP2cFVn5qEfuzfXeq+UcCpxXg7PFIzO+z1r3vXy9lQ5SQQXUvhyWspWuixBbtps4KqraAKj65D3LPIKBQml5EhQ==; Received: from [81.0.34.67] (helo=perseus.local) by fanzine.igalia.com with esmtpsa (Cipher TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim) id 1kGQeR-0007HB-Gc; Thu, 10 Sep 2020 19:46:27 +0200 Received: from berto by perseus.local with local (Exim 4.92) (envelope-from ) id 1kGQeC-0006qB-R4; Thu, 10 Sep 2020 19:46:12 +0200 From: Alberto Garcia To: qemu-devel@nongnu.org Subject: [PATCH v3 1/2] qcow2: Report BDRV_BLOCK_ZERO more accurately in bdrv_co_block_status() Date: Thu, 10 Sep 2020 19:46:01 +0200 Message-Id: <104cbe2dfac940e4c5ca0a7e2eb22a0245e206f7.1599759873.git.berto@igalia.com> 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 = 2020/09/10 13:46:27 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+qemu-devel=archiver.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 ad3a51ed53..1b0ae29610 100644 --- a/block/io.c +++ b/block/io.c @@ -2408,16 +2408,16 @@ 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) { - if (bs->backing) { + } else if (bs->drv->supports_backing) { + if (!bs->backing) { + ret |= BDRV_BLOCK_ZERO; + } else if (want_zero) { BlockDriverState *bs2 = bs->backing->bs; int64_t size2 = bdrv_getlength(bs2); if (size2 >= 0 && offset >= size2) { ret |= BDRV_BLOCK_ZERO; } - } else { - ret |= BDRV_BLOCK_ZERO; } }