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 65E3CC54EE9 for ; Fri, 9 Sep 2022 01:08:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229551AbiIIBID (ORCPT ); Thu, 8 Sep 2022 21:08:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229507AbiIIBIC (ORCPT ); Thu, 8 Sep 2022 21:08:02 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [IPv6:2001:67c:2178:6::1c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 12F44E7FBC; Thu, 8 Sep 2022 18:08:01 -0700 (PDT) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out1.suse.de (Postfix) with ESMTPS id 57C26336D9; 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Fri, 9 Sep 2022 01:07:50 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id lfEpIeaRGmPYPAAAMHmgww (envelope-from ); Fri, 09 Sep 2022 01:07:50 +0000 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit MIME-Version: 1.0 From: "NeilBrown" To: "Trond Myklebust" Cc: "jlayton@kernel.org" , "zohar@linux.ibm.com" , "djwong@kernel.org" , "xiubli@redhat.com" , "brauner@kernel.org" , "bfields@fieldses.org" , "linux-api@vger.kernel.org" , "linux-xfs@vger.kernel.org" , "david@fromorbit.com" , "fweimer@redhat.com" , "linux-kernel@vger.kernel.org" , "chuck.lever@oracle.com" , "linux-man@vger.kernel.org" , "linux-nfs@vger.kernel.org" , "tytso@mit.edu" , "viro@zeniv.linux.org.uk" , "jack@suse.cz" , "linux-ext4@vger.kernel.org" , "linux-btrfs@vger.kernel.org" , "linux-fsdevel@vger.kernel.org" , "adilger.kernel@dilger.ca" , "lczerner@redhat.com" , "ceph-devel@vger.kernel.org" Subject: Re: [man-pages RFC PATCH v4] statx, inode: document the new STATX_INO_VERSION field In-reply-to: <166268467103.30452.1687952324107257676@noble.neil.brown.name> References: <20220907111606.18831-1-jlayton@kernel.org>, <166255065346.30452.6121947305075322036@noble.neil.brown.name>, <79aaf122743a295ddab9525d9847ac767a3942aa.camel@kernel.org>, <20220907125211.GB17729@fieldses.org>, <771650a814ab1ff4dc5473d679936b747d9b6cf5.camel@kernel.org>, <20220907135153.qvgibskeuz427abw@quack3>, <166259786233.30452.5417306132987966849@noble.neil.brown.name>, <20220908083326.3xsanzk7hy3ff4qs@quack3>, , <02928a8c5718590bea5739b13d6b6ebe66cac577.camel@kernel.org>, <166267775728.30452.17640919701924887771@noble.neil.brown.name>, <91e31d20d66d6f47fe12c80c34b1cffdfc202b6a.camel@hammerspace.com>, <166268467103.30452.1687952324107257676@noble.neil.brown.name> Date: Fri, 09 Sep 2022 11:07:47 +1000 Message-id: <166268566751.30452.13562507405746100242@noble.neil.brown.name> Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org On Fri, 09 Sep 2022, NeilBrown wrote: > On Fri, 09 Sep 2022, Trond Myklebust wrote: > > > > > IOW: the minimal condition needs to be that for all cases below, the > > application reads 'state B' as having occurred if any data was > > committed to disk before the crash. > > > > Application Filesystem > > =========== ========= > > read change attr <- 'state A' > > read data <- 'state A' > > write data -> 'state B' > > + > > read change attr <- 'state B' > > The important thing here is to not see 'state A'. Seeing 'state C' > should be acceptable. Worst case we could merge in wall-clock time of > system boot, but the filesystem should be able to be more helpful than > that. > Actually, without the crash+reboot it would still be acceptable to see "state A" at the end there - but preferably not for long. >From the NFS perspective, the changeid needs to update by the time of a close or unlock (so it is visible to open or lock), but before that it is just best-effort. NeilBrown