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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 EBF9DC43381 for ; Mon, 25 Feb 2019 14:49:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C48F620643 for ; Mon, 25 Feb 2019 14:49:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727555AbfBYOtI (ORCPT ); Mon, 25 Feb 2019 09:49:08 -0500 Received: from mail-pg1-f195.google.com ([209.85.215.195]:42729 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726313AbfBYOtH (ORCPT ); Mon, 25 Feb 2019 09:49:07 -0500 Received: by mail-pg1-f195.google.com with SMTP id b2so4590102pgl.9 for ; Mon, 25 Feb 2019 06:49:07 -0800 (PST) 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=mMDQumBGVXpA3A1u4UOXH2tePQ2H7YXxmyd0MJ93a4Q=; b=FeDDEMSQxANdvGP25fOT3dUU7Vgi40O3DSA/8aelDcdJF09mV6KXCuiSxnnSfSjZmX rTSXAljc0WE6++WH6CHmXlKmSILfY7uPFwo4HsUNVwj/d8VzHQbuZfgmZffcmbECVTLe fEASjglosxLaYwAjifwt6uvl6/wkSsaTwd2MBdOL5fI0axdUGaHYp/YeFUQLgmSzC+u4 dy551Z1KrA+0Gg3NlstEd0DVtwlmelZviJkS15Qni1TtzwdDFYOCTboej/Dk6mfH7NHn HjZ3ah7jLzp96h09Q3QEMx1SqdiSu8fC3k2WUIVyQCM4g36JJy072TwptFi/d+5WW0mo go4w== X-Gm-Message-State: AHQUAub+KrJ5fxr4g8+XkpRk65rXHGk22yfSIfO+OMCKiw5bhXolutBv 4cJ3BKdH4hlIoVcbf7D6BDIHdNHb X-Google-Smtp-Source: AHgI3IYJhe/DuxMP/ysKFcjFWRt9pk/xQrEtvzyMHX99Heut/bx18rhPswX/zVKvklhFpc9LT2NAMA== X-Received: by 2002:a63:144:: with SMTP id 65mr19648980pgb.38.1551106146952; Mon, 25 Feb 2019 06:49:06 -0800 (PST) Received: from asus.site ([2601:647:4000:5dd1:a41e:80b4:deb3:fb66]) by smtp.gmail.com with ESMTPSA id o5sm27955002pfi.118.2019.02.25.06.49.05 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 25 Feb 2019 06:49:05 -0800 (PST) Subject: Re: [PATCH] nvmet: disable direct I/O when unavailable To: Johannes Thumshirn , Max Gurtovoy , Chaitanya Kulkarni , Christoph Hellwig Cc: Linux Kernel Mailinglist , Linux NVMe Mailinglist References: <20190221182234.22345-1-jthumshirn@suse.de> <6c3fa30a-d516-a453-a001-1014202ff9ce@suse.de> <9d8e96de-d68d-8961-21e8-4cb8e79b4a08@mellanox.com> <2185e4e5-086a-d0c2-0fee-a7a5c98267bb@suse.de> From: Bart Van Assche Message-ID: Date: Mon, 25 Feb 2019 06:49:04 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.5.0 MIME-Version: 1.0 In-Reply-To: <2185e4e5-086a-d0c2-0fee-a7a5c98267bb@suse.de> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2/25/19 1:37 AM, Johannes Thumshirn wrote: > On 24/02/2019 11:54, Max Gurtovoy wrote: >> What is the status of iSCSI/SRP targets in this case ? > > iSCSI/SRP passes in the following: > > /* > * Use O_DSYNC by default instead of O_SYNC to forgo syncing > * of pure timestamp updates. > */ > flags = O_RDWR | O_CREAT | O_LARGEFILE | O_DSYNC; That code fragment comes from the LIO file backend. There is no requirement for a SCSI target core file backend to use O_DSYNC. SCST allows users to choose whether or not O_DSYNC should be used: if (virt_dev->wt_flag && !virt_dev->nv_cache) open_flags |= O_DSYNC; Bart.