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=-3.6 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 5DC3BC43461 for ; Mon, 7 Sep 2020 07:03:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FFB22177B for ; Mon, 7 Sep 2020 07:03:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="eGZAavdZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726896AbgIGHCU (ORCPT ); Mon, 7 Sep 2020 03:02:20 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58736 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726771AbgIGHCJ (ORCPT ); Mon, 7 Sep 2020 03:02:09 -0400 Received: from mail-wr1-x443.google.com (mail-wr1-x443.google.com [IPv6:2a00:1450:4864:20::443]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8BE63C061574; Mon, 7 Sep 2020 00:02:08 -0700 (PDT) Received: by mail-wr1-x443.google.com with SMTP id g4so14563479wrs.5; Mon, 07 Sep 2020 00:02:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=ylv/Ec3IQY/nRnVl7KUf4rlIbzcbzilcAdfCxVxqCdM=; b=eGZAavdZlKtcT3lSWI7KautQwycdwOhhWwW/QEDVhWUcao0t3/TnmTEfUdfslBudpC 8nOaO+bFIkEwWAZNjSOuhZ6S26BDST+w8i732lh7nQ3kIYL04wbpYO6FdH0Xvm/2JWaJ ySiPaxUHkEGfTtRKfTj2b7T2yXI56gul9vy5dixsvYnOcR6BLkNU5NcTV5022OWDUrso uPL9AKxRJWrPp+jiZrtrq8sEq5j4iSINePJYRZ86f9QwUqYx7XzAfdVcV+/qz1oqvkxz NHic36LO7xaBXZ7JXPidaQ6oPLkn4BoGtaSdmOAQohYSiqIQdzMaGTWbAUJrsDHKZnGF B4dQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ylv/Ec3IQY/nRnVl7KUf4rlIbzcbzilcAdfCxVxqCdM=; b=kQUDjwR2DxLPzrntfzoR9k/MdjyFt6rlbGZtMCSw5Vt9VpyCtCFFU4semoqizrrweQ VUypzNBmKZDVrMZmd0EGCI9UnRTGogBSVjnBKhcbYs+0xk6B9KoC1fpGQ+xIDTLL8QLR 2mmrM506vf4qZylzZJVelTBeQyroR0tfryYQtBu0eDUUtTNLc0DnM+MDLU0kszCDO+l3 kZO8cmvGqknukajxJFLlc4u363sH1KpSSVcSnpMwvPVYZ45x9OsHDHJa9qcrTikGFVfE xabPK9yEfFvwddCm3whbjkjFAZiMoCR2g6tohykE9gAsB1qX3q87x8LNADmgFN3d74U0 w4yw== X-Gm-Message-State: AOAM531PTa1voJrZuf1Y/KWhLy0ldCfaU5mGR2l7OoP42nrrKS+7iTY9 oeOhqr243+cKS7HFCjoQZR5E+ochjg20EumOTlU= X-Google-Smtp-Source: ABdhPJw8TAjLd5BYGCY0Tr5/xWkqYwtfubZPgWpkYEtQ1vEu4nZ7Ih5my0t7n5KCYlQdFMaMMGHicv8EGLY6kCKlCsI= X-Received: by 2002:adf:dd51:: with SMTP id u17mr19759514wrm.355.1599462127129; Mon, 07 Sep 2020 00:02:07 -0700 (PDT) MIME-Version: 1.0 References: <20200731064526.GA25674@infradead.org> <20200731091416.GA29634@infradead.org> <20200731094135.GA4104@infradead.org> <20200731125110.GA11500@infradead.org> <20200814081411.GA16943@infradead.org> In-Reply-To: <20200814081411.GA16943@infradead.org> From: Kanchan Joshi Date: Mon, 7 Sep 2020 12:31:42 +0530 Message-ID: Subject: Re: [PATCH v4 6/6] io_uring: add support for zone-append To: "hch@infradead.org" Cc: Damien Le Moal , Jens Axboe , Pavel Begunkov , Kanchan Joshi , "viro@zeniv.linux.org.uk" , "bcrl@kvack.org" , Matthew Wilcox , "linux-fsdevel@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-aio@kvack.org" , "io-uring@vger.kernel.org" , "linux-block@vger.kernel.org" , "linux-api@vger.kernel.org" , SelvaKumar S , Nitesh Shetty , Javier Gonzalez , Johannes Thumshirn , Naohiro Aota Content-Type: text/plain; charset="UTF-8" Sender: linux-api-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, Aug 14, 2020 at 1:44 PM hch@infradead.org wrote: > > On Wed, Aug 05, 2020 at 07:35:28AM +0000, Damien Le Moal wrote: > > > the write pointer. The only interesting addition is that we also want > > > to report where we wrote. So I'd rather have RWF_REPORT_OFFSET or so. > > > > That works for me. But that rules out having the same interface for raw block > > devices since O_APPEND has no meaning in that case. So for raw block devices, it > > will have to be through zonefs. That works for me, and I think it was your idea > > all along. Can you confirm please ? > > Yes. I don't think think raw syscall level access to the zone append > primitive makes sense. Either use zonefs for a file-like API, or > use the NVMe pass through interface for 100% raw access. But there are use-cases which benefit from supporting zone-append on raw block-dev path. Certain user-space log-structured/cow FS/DB will use the device that way. Aerospike is one example. Pass-through is synchronous, and we lose the ability to use io-uring. For async uring/aio to block-dev, file-pointer will not be moved to EoF, but that position was not very important anyway- as with this interface we expect many async appends outstanding, all with zone-start. Do you think RWF_APPEND | RWF_REPORT_OFFSET_DIRECT/INDIRECT is too bad for direct block-dev. Could you please suggest another way to go about it? -- Kanchan