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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 467CCC433DF for ; Fri, 19 Jun 2020 07:56:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 158C0207DD for ; Fri, 19 Jun 2020 07:56:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lblZEhu1" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730934AbgFSH41 (ORCPT ); Fri, 19 Jun 2020 03:56:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46756 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730875AbgFSH41 (ORCPT ); Fri, 19 Jun 2020 03:56:27 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79B48C06174E; Fri, 19 Jun 2020 00:56:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=+6lPoVcKNlDZ05zKLgAxZCl2a/rH2CM1rj4HgNIEc9s=; b=lblZEhu1fj4HGfeB9rhLnm35e9 3s57GAEQfeYx9h5CBtLLPeAfKEWKCz18DZbbPCosACUyBaHUXmzsIVHYCRGJVPG9fd8muPAzgwPu1 V/71pp368G0BLs+SJP1MgF8kDjX9G90M/thlJtpGLGS6/TUykwIDqd0wDpgWHY4LmSnrbOJwFkW1u bmIqEbVSMPVmLVAbNEJ5TT97yQsdSJgNJgeiBPRVLvomB3zVX+sRq5JZ18lk3/mWl7wLGKMGBZxPo lC7rsgOSIPzShQNsWEImEJA6EBemQePknjzZd+JcfY94JHq401SFPp4B4rNlvgjY1ed3aLR1jCiWB Xru8sLrw==; Received: from hch by bombadil.infradead.org with local (Exim 4.92.3 #3 (Red Hat Linux)) id 1jmBsq-000095-Sv; Fri, 19 Jun 2020 07:56:20 +0000 Date: Fri, 19 Jun 2020 00:56:20 -0700 From: Christoph Hellwig To: Kanchan Joshi Cc: Christoph Hellwig , axboe@kernel.dk, viro@zeniv.linux.org.uk, bcrl@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-aio@kvack.org, io-uring@vger.kernel.org, linux-block@vger.kernel.org, selvakuma.s1@samsung.com, nj.shetty@samsung.com, javier.gonz@samsung.com Subject: Re: [PATCH 0/3] zone-append support in aio and io-uring Message-ID: <20200619075620.GA20581@infradead.org> References: <1592414619-5646-1-git-send-email-joshi.k@samsung.com> <20200618065634.GB24943@infradead.org> <20200618175258.GA4141152@test-zns> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200618175258.GA4141152@test-zns> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org On Thu, Jun 18, 2020 at 11:22:58PM +0530, Kanchan Joshi wrote: > I was thinking of raw block-access to zone device rather than pristine file > abstraction. Why? > And in that context, semantics, at this point, are unchanged > (i.e. same as direct writes) while flexibility of async-interface gets > added. > Synchronous-writes on single-zone sound fine, but synchronous-appends on > single-zone do not sound that fine. Where does synchronous access come into play? > > What could be a useful addition is a way for O_APPEND/RWF_APPEND writes > > to report where they actually wrote, as that comes close to Zone Append > > while still making sense at our usual abstraction level for file I/O. > > Thanks for suggesting this. O and RWF_APPEND may not go well with block > access as end-of-file will be picked from dev inode. No, but they go really well with zonefs. > But perhaps a new > flag like RWF_ZONE_APPEND can help to transform writes (aio or uring) > into append without introducing new opcodes. I don't think this is a good idea. Zones are a concept for a a very specific class of zoned devices. Trying to shoe-horn this into the byte address files / whole device abstraction not only is ugly conceptually but also adds the overhead for it to the VFS. And O_APPEND that returns the written position OTOH makes total sense at the file level as well and not just for raw zoned devices.