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 EB8B0C6FA8B for ; Mon, 12 Sep 2022 13:21:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229760AbiILNVD (ORCPT ); Mon, 12 Sep 2022 09:21:03 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35990 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229510AbiILNVB (ORCPT ); Mon, 12 Sep 2022 09:21:01 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 26B2E220E7 for ; Mon, 12 Sep 2022 06:21:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662988860; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QcJ4hYnOykjT5bKhT2L+jboPTMLweg9s7FN9sWH8lgs=; b=R+IEGRYJsTiOss+8stX4KjTTv5HBCoTikG2U1bbvaVlQVxrOqfdGmawL78OpUGvLo+v9VH GsOXFo5CV8UcugZ+OfsrWOgrZgO9eXJ/yHHa9w8w9KVz7ThmP9WgyssJTNSpQf98Wvr/R0 rJFnFNe2YEs+lDON6JszAS3DCgd1IjI= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-668-L4qFUPMqPwu7x2MEi03oxQ-1; Mon, 12 Sep 2022 09:20:54 -0400 X-MC-Unique: L4qFUPMqPwu7x2MEi03oxQ-1 Received: from smtp.corp.redhat.com (int-mx09.intmail.prod.int.rdu2.redhat.com [10.11.54.9]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 62D7529ABA1F; Mon, 12 Sep 2022 13:20:53 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.193.57]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7BE4249BB60; Mon, 12 Sep 2022 13:20:48 +0000 (UTC) From: Florian Weimer To: Jeff Layton Cc: "J. Bruce Fields" , Theodore Ts'o , Jan Kara , NeilBrown , adilger.kernel@dilger.ca, djwong@kernel.org, david@fromorbit.com, trondmy@hammerspace.com, viro@zeniv.linux.org.uk, zohar@linux.ibm.com, xiubli@redhat.com, chuck.lever@oracle.com, lczerner@redhat.com, brauner@kernel.org, linux-man@vger.kernel.org, linux-api@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, ceph-devel@vger.kernel.org, linux-ext4@vger.kernel.org, linux-nfs@vger.kernel.org, linux-xfs@vger.kernel.org Subject: Re: [man-pages RFC PATCH v4] statx, inode: document the new STATX_INO_VERSION field References: <166259786233.30452.5417306132987966849@noble.neil.brown.name> <20220908083326.3xsanzk7hy3ff4qs@quack3> <02928a8c5718590bea5739b13d6b6ebe66cac577.camel@kernel.org> <20220908155605.GD8951@fieldses.org> <9e06c506fd6b3e3118da0ec24276e85ea3ee45a1.camel@kernel.org> <20220908182252.GA18939@fieldses.org> <44efe219dbf511492b21a653905448d43d0f3363.camel@kernel.org> <20220909154506.GB5674@fieldses.org> <125df688dbebaf06478b0911e76e228e910b04b3.camel@kernel.org> <20220910145600.GA347@fieldses.org> <9eaed9a47d1aef11fee95f0079e302bc776bc7ff.camel@kernel.org> <87a67423la.fsf@oldenburg.str.redhat.com> <7c71050e139a479e08ab7cf95e9e47da19a30687.camel@kernel.org> Date: Mon, 12 Sep 2022 15:20:46 +0200 In-Reply-To: <7c71050e139a479e08ab7cf95e9e47da19a30687.camel@kernel.org> (Jeff Layton's message of "Mon, 12 Sep 2022 08:55:04 -0400") Message-ID: <875yhs20gh.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.9 Precedence: bulk List-ID: X-Mailing-List: linux-api@vger.kernel.org * Jeff Layton: > On Mon, 2022-09-12 at 14:13 +0200, Florian Weimer wrote: >> * Jeff Layton: >>=20 >> > To do this we'd need 2 64-bit fields in the on-disk and in-memory=20 >> > superblocks for ext4, xfs and btrfs. On the first mount after a crash, >> > the filesystem would need to bump s_version_max by the significant >> > increment (2^40 bits or whatever). On a "clean" mount, it wouldn't need >> > to do that. >> >=20 >> > Would there be a way to ensure that the new s_version_max value has ma= de >> > it to disk? Bumping it by a large value and hoping for the best might = be >> > ok for most cases, but there are always outliers, so it might be >> > worthwhile to make an i_version increment wait on that if necessary.=20 >>=20 >> How common are unclean shutdowns in practice? Do ex64/XFS/btrfs keep >> counters in the superblocks for journal replays that can be read easily? >>=20 >> Several useful i_version applications could be negatively impacted by >> frequent i_version invalidation. >>=20 > > One would hope "not very often", but Oopses _are_ something that happens > occasionally, even in very stable environments, and it would be best if > what we're building can cope with them. I was wondering if such unclean shutdown events are associated with SSD =E2=80=9Cunsafe shutdowns=E2=80=9D, as identified by the SMART counter. I = think those aren't necessarily restricted to oopses or various forms of powerless (maybe depending on file system/devicemapper configuration)? I admit it's possible that the file system is shut down cleanly before the kernel requests the power-off state from the firmware, but the underlying SSD is not. Thanks, Florian