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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 CCB73C31E40 for ; Mon, 10 Jun 2019 16:12:15 +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 A55F5206C3 for ; Mon, 10 Jun 2019 16:12:15 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A55F5206C3 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:48176 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1haMu6-0004eF-AZ for qemu-devel@archiver.kernel.org; Mon, 10 Jun 2019 12:12:14 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:58051) by lists.gnu.org with esmtp (Exim 4.86_2) (envelope-from ) id 1haMlY-0005GZ-W3 for qemu-devel@nongnu.org; Mon, 10 Jun 2019 12:03:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1haMlV-0001Ij-8A for qemu-devel@nongnu.org; Mon, 10 Jun 2019 12:03:23 -0400 Received: from mail-wr1-f67.google.com ([209.85.221.67]:44246) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1haMlT-0001Fu-7x for qemu-devel@nongnu.org; Mon, 10 Jun 2019 12:03:21 -0400 Received: by mail-wr1-f67.google.com with SMTP id b17so9741774wrq.11 for ; Mon, 10 Jun 2019 09:03:16 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=EMEIUl3j847StX1Rt48Sbec7vmv0DT9VVKAzaHTI9b8=; b=oGiaXUIag9lVJAcDaod5+5q910xC/Lo3s5JX+HO2fJOyUndt/jX4UyKVSW2exS6ASJ 193MvF9ipMxPv0Hkp8tzRG/1ks5U6VFRelzzGAMQuyEJKu1djiUBIPvnjjlYn0xO9nRX G6+TaLoqEwwHS7Ic6Bl5z+oXIkcsDnbaCywSMxjsNJm8B2eakv3fv1/66JfNYLeciajW JcTT1L1Z0x7/f6edoPVf/Yfd/zwOXAc3cZadjWJaTanHEsBI0HLtrnZ7ZKM0evVOYZpP YpoBexSwIK1YY/9JBSUoxrgXyb9oA/4YEzfJTtz9xqlv/Bnm7NLOyeUFS8scz873SUNd mReQ== X-Gm-Message-State: APjAAAXUKYXGragTB7xQs+hyrItJTkW2LoLzt/GUjZfQoF+ngQvL1gVe s7uFxkbxd7evPHqdIZ0HO3+NqA== X-Google-Smtp-Source: APXvYqwJ3Zj0eez7E+KsfPPCZGNEcMxVQcdzUN/n15dDUQDlOejYwcZgHv2c1nFL2N/tYjOPF2Ay2A== X-Received: by 2002:a5d:5189:: with SMTP id k9mr3057986wrv.45.1560182595228; Mon, 10 Jun 2019 09:03:15 -0700 (PDT) Received: from ?IPv6:2001:b07:6468:f312:49d3:a711:c5a3:8ebf? ([2001:b07:6468:f312:49d3:a711:c5a3:8ebf]) by smtp.gmail.com with ESMTPSA id x15sm7988665wrt.87.2019.06.10.09.03.13 (version=TLS1_3 cipher=AEAD-AES128-GCM-SHA256 bits=128/128); Mon, 10 Jun 2019 09:03:14 -0700 (PDT) To: l00284672 , stefanha@redhat.com, mreitz@redhat.com, kwolf@redhat.com References: <1560173684-6264-1-git-send-email-lizhengui@huawei.com> <1a218c83-7167-68c4-798f-2870f2f98475@redhat.com> <49e6310d-1c1c-2379-47e6-7239e0058e78@huawei.com> From: Paolo Bonzini Message-ID: <487a3a9d-92b3-bed4-4082-5701cd4bd08d@redhat.com> Date: Mon, 10 Jun 2019 18:03:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <49e6310d-1c1c-2379-47e6-7239e0058e78@huawei.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.85.221.67 Subject: Re: [Qemu-devel] [Qemu-block] [PATCH] file-posix: unlock qemu_global_mutex before pread when attach disk 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: jiangyiwen@huawei.com, eric.fangyi@huawei.com, qemu-devel@nongnu.org, qemu-block@nongnu.org, wangjie88@huawei.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 10/06/19 16:51, l00284672 wrote: > The pread will hang in attaching disk just when backend storage network > disconnection . Would the "open" hang as well in that case? > I think the locking range of qemu_global_mutex is too large when do qmp > operation. what > does the qemu_global_mutex  really protect? Basically everything. > what is the risk of unlocking qemu_global_mutex in qmp? It's not QMP; it's specifically the code that calls raw_probe_alignment. Paolo