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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id EAF22C77B7C for ; Fri, 5 May 2023 22:04:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=sqnccyk/dMZ2wf4F3TQE4sRZTZA9O4nCyO6tYuFcb+4=; b=H61v0C1TuG4qlPqWGYbXv238ik Mj4F46AR3+EnUPVGAqtvq0FuYIH9s4axsJjaEO9u0tDX/vmXjTgw8Zl2ekwBcH0YBDQoiPQaWj0Iz gieo5znp7IXjMh1H/yoTDxbZXlHaoG2MRo98psSGZDE34z4JN/B38ZjpqEvf8JDL4zkeddvuh/bfR MlU/WzREUWrLuIFfoYNFZ5l46Z3DoXkywuV+umyWY9nW1lEZnsXs8m8pdxJ3ZgNnp8ZggNk9CATC4 KTS5TOPCjtFeID/lZT+PtZ2ayUSoffzOpk63GS0Ko2BkjUYihEIt5aGrBrIHuNif0IuuPVPueaPSc EyAhg78w==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1pv3Xg-00BwUO-07; Fri, 05 May 2023 22:04:44 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1pv3Xd-00BwTk-1O for linux-nvme@lists.infradead.org; Fri, 05 May 2023 22:04:42 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E73FB6411F; Fri, 5 May 2023 22:04:40 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4A297C433D2; Fri, 5 May 2023 22:04:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1683324280; bh=f1jvZDrF9Qn33CLcZ4WNk/v3Df+AvMJXxv7DwWGW0QQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OkpKowf89TZVFXs+kZPV9yhxvlS1WPcn+RJAUjhk+F+NdGsM3DowjGujTCVspntEk cjONoTzL+Mbd5t+9AKB6wfFG/v2mMcL4zUbTCd68MALmZ0bvdAsdyqB1NiUPsHURQx Pb+EiF47Gw2FrzOLU0+uch5xJIwNkrwQ88DqtgRjz2heN6tSAyMM3taWJ6o/co195G InfdsysxEKZtg6MGDEsuLv05bAtcsJBM0d3KZPxDWL0S6H+Cc+wgMhp3zHymC2qu4N b7tWMZGshPp0ERKEWKp+Mkk6aHJZ+zyeGly/ASTr+Ej/LlVg2ok1XVQwXyBr+Dr0m5 X42vWMe7zA2bg== Date: Fri, 5 May 2023 15:04:39 -0700 From: "Darrick J. Wong" To: John Garry Cc: Dave Chinner , axboe@kernel.dk, kbusch@kernel.org, hch@lst.de, sagi@grimberg.me, martin.petersen@oracle.com, viro@zeniv.linux.org.uk, brauner@kernel.org, dchinner@redhat.com, jejb@linux.ibm.com, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-scsi@vger.kernel.org, linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, paul@paul-moore.com, jmorris@namei.org, serge@hallyn.com, Prasad Singamsetty Subject: Re: [PATCH RFC 02/16] fs/bdev: Add atomic write support info to statx Message-ID: <20230505220439.GK15394@frogsfrogsfrogs> References: <20230503183821.1473305-1-john.g.garry@oracle.com> <20230503183821.1473305-3-john.g.garry@oracle.com> <20230503215846.GE3223426@dread.disaster.area> <96a2f875-7f99-cd36-e9c3-abbadeb9833b@oracle.com> <20230504224033.GJ3223426@dread.disaster.area> <644fe4aa-cb89-0c14-4c90-cc93bcc6bbc2@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <644fe4aa-cb89-0c14-4c90-cc93bcc6bbc2@oracle.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230505_150441_554776_A6511D7D X-CRM114-Status: GOOD ( 26.47 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, May 05, 2023 at 09:01:58AM +0100, John Garry wrote: > On 04/05/2023 23:40, Dave Chinner wrote: > > Hi Dave, > > > > No, not yet. Is it normally expected to provide a proposed man page update > > > in parallel? Or somewhat later, when the kernel API change has some > > > appreciable level of agreement? > > Normally we ask for man page updates to be presented at the same > > time, as the man page defines the user interface that is being > > implemented. In this case, we need updates for the pwritev2() man > > page to document RWF_ATOMIC semantics, and the statx() man page to > > document what the variables being exposed mean w.r.t. RWF_ATOMIC. > > > > The pwritev2() man page is probably the most important one right now > > - it needs to explain the guarantees that RWF_ATOMIC is supposed to > > provide w.r.t. data integrity, IO ordering, persistence, etc. > > Indeed, it will need to explain exactly how this "multi-atomic-unit > > mulit-bio non-atomic RWF_ATOMIC" IO thing can be used safely and > > reliably, especially w.r.t. IO ordering and persistence guarantees > > in the face of crashes and power failures. Not to mention > > documenting error conditions specific to RWF_ATOMIC... > > > > It's all well and good to have some implementation, but without > > actually defining and documenting the*guarantees* that RWF_ATOMIC > > provides userspace it is completely useless for application > > developers. And from the perspective of a reviewer, without the > > documentation stating what the infrastructure actually guarantees > > applications, we can't determine if the implementation being > > presented is fit for purpose.... > > ok, understood. Obviously from any discussion so far there are many details > which the user needs to know about how to use this interface and what to > expect. > > We'll look to start working on those man page details now. Agreed. The manpage contents are what needs to get worked on at LSFMM where you'll have various block/fs/storage device people in the same room with which to discuss various issues and try to smooth out the misundertandings. (Also: I've decided to cancel my in-person attendance due to a sudden health issue. I'll still be in the room, just virtually now. :() --D > Thanks, > John