From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 56D37C6FA82 for ; Fri, 23 Sep 2022 14:31:06 +0000 (UTC) Received: from localhost ([::1]:40032 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1objho-0000vz-VP for qemu-devel@archiver.kernel.org; Fri, 23 Sep 2022 10:31:04 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:49408) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1objfG-0008T2-5g for qemu-devel@nongnu.org; Fri, 23 Sep 2022 10:28:26 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:20412) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1objfB-00031J-Kf for qemu-devel@nongnu.org; Fri, 23 Sep 2022 10:28:23 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663943300; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=+q+6CUAHTLCWAE6RxURz3B2yVNjv9uGqyp/1OLGnPSQ=; b=W/s5wRrSFCRRO1+O79XfL/ZzEW6dF0cefif1XtkOVzN7bjTdOkZpuRWcXK7rgOyFkZY/1s glQE9vkw7vulA88xEfZm6Hhdi7EnrfvZI2zYDUw2hIaZUgBG28MBshgH2myZ2pryeqId/W IonmBjIr3ANqluA3Xjah1TN//TFSHiI= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-45-rVmqBf8CN3e5eERVbRHGlA-1; Fri, 23 Sep 2022 10:28:17 -0400 X-MC-Unique: rVmqBf8CN3e5eERVbRHGlA-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.rdu2.redhat.com [10.11.54.6]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 3D6F1185A78B; Fri, 23 Sep 2022 14:28:17 +0000 (UTC) Received: from redhat.com (unknown [10.39.193.141]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7B4DF2166B2A; Fri, 23 Sep 2022 14:28:16 +0000 (UTC) Date: Fri, 23 Sep 2022 16:28:14 +0200 From: Kevin Wolf To: luzhipeng Cc: qemu-devel , qemu-block@nongnu.org, Hanna Reitz Subject: Re: [PATCH] block: unmap (discard) blocks only if discard_zeros flag is true Message-ID: References: <20220923100224.537-1-luzhipeng@cestc.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220923100224.537-1-luzhipeng@cestc.cn> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Received-SPF: pass client-ip=170.10.129.124; envelope-from=kwolf@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Am 23.09.2022 um 12:02 hat luzhipeng geschrieben: > From: lu zhipeng > > we can unmap(discard) blocks for block devices of supporting discard zeros > or regular file. > > Signed-off-by: lu zhipeng This more or less restores the state before commit 34fa110e. The commit message there explains that s->discard_zeroes is unreliable (in particular, it is false on block devices on recent kernels even though they may support zeroing by discard just fine). We should instead remove s->discard_zeroes because it is currently unused. I'll send a patch. Kevin