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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0B2ECC32771 for ; Thu, 22 Sep 2022 02:13:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231158AbiIVCNy (ORCPT ); Wed, 21 Sep 2022 22:13:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41800 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231159AbiIVCNs (ORCPT ); Wed, 21 Sep 2022 22:13:48 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 9ED239C236 for ; Wed, 21 Sep 2022 19:13:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1663812826; 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=la998Fhh07Iapm6q9oJ6N9PKQNKvsYQdU7CIA3wD4kk=; b=BmIXEbtXzKaqTtLF2m7wm8aHfTBTkxsGIMUpmBKW3uebv+cuGJlXGoeYLBTFN2xp/rebGD Y9mbCDaPbd03oqN56jo2YdzDQF9XZZQ1wgNn5PUwnQUCPQdsNj6kjdgg6Aa0IInNmFvZp7 3PGD3eypIBXRwH8Q3vNmDXUcH0UK6Gk= 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-655-MdOlDXeCNyqMlsFfMDMc9g-1; Wed, 21 Sep 2022 22:13:43 -0400 X-MC-Unique: MdOlDXeCNyqMlsFfMDMc9g-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 C3E8F85A5A6; Thu, 22 Sep 2022 02:13:42 +0000 (UTC) Received: from T590 (ovpn-8-16.pek2.redhat.com [10.72.8.16]) by smtp.corp.redhat.com (Postfix) with ESMTPS id F25382166B2C; Thu, 22 Sep 2022 02:13:30 +0000 (UTC) Date: Thu, 22 Sep 2022 10:13:25 +0800 From: Ming Lei To: ZiyangZhang Cc: axboe@kernel.dk, xiaoguang.wang@linux.alibaba.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, joseph.qi@linux.alibaba.com Subject: Re: [PATCH V4 6/8] ublk_drv: support UBLK_F_USER_RECOVERY_REISSUE Message-ID: References: <20220921095849.84988-1-ZiyangZhang@linux.alibaba.com> <20220921095849.84988-7-ZiyangZhang@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220921095849.84988-7-ZiyangZhang@linux.alibaba.com> X-Scanned-By: MIMEDefang 3.1 on 10.11.54.6 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 21, 2022 at 05:58:47PM +0800, ZiyangZhang wrote: > UBLK_F_USER_RECOVERY_REISSUE implies that: > With a dying ubq_daemon, ublk_drv let monitor_work requeues rq issued to > userspace(ublksrv) before the ubq_daemon is dying. > > UBLK_F_USER_RECOVERY_REISSUE is designed for backends which: > (1) tolerate double-write since ublk_drv may issue the same rq > twice. > (2) does not let frontend users get I/O error, such as read-only FS > and VM backend. > > Signed-off-by: ZiyangZhang > --- Reviewed-by: Ming Lei Thanks, Ming