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 4AF7FE748E9 for ; Sun, 1 Oct 2023 05:39:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234302AbjJAFjZ (ORCPT ); Sun, 1 Oct 2023 01:39:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229455AbjJAFjX (ORCPT ); Sun, 1 Oct 2023 01:39:23 -0400 X-Greylist: delayed 2207 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Sat, 30 Sep 2023 22:39:18 PDT Received: from mx08-006a4e02.pphosted.com (mx08-006a4e02.pphosted.com [143.55.148.243]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7AD9FC5; Sat, 30 Sep 2023 22:39:18 -0700 (PDT) Received: from pps.filterd (m0316693.ppops.net [127.0.0.1]) by mx08-006a4e02.pphosted.com (8.17.1.22/8.17.1.22) with ESMTP id 3913gioS006695; Sun, 1 Oct 2023 07:02:18 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=iram.es; h=date :from:to:cc:subject:message-id:references:mime-version :content-type:in-reply-to:content-transfer-encoding; s=dkim3; bh=5JgHwkJ5bZA+PRufvniyMuRJN1Jr6719sKCuadOAMmw=; b=hDNmwqgug1An fvwB2cRTfoutFDu+tai+5nrTyDJGpD0Pkv+UoD9dDHnHHIAd09gz+r02mse1Cs9K ZCgOca/WGL5QjFanXXswWHZ9gsDFv9HUsGVbSl0NWG9zgx7F1IrS1vcyAC4I2TBu vtCiSXblwT2BOKB168GcAoNAG3zywK5ZIdX9TFP4bHS8GBFExgd9NXibijGF4eid NlYGioPXJRFaYlb2eKu0casy5f5iNW/FoS1c0RbxZP9tWhnpwN4+plV0Uq3PyrZu vjfbiPtJ7zPzKAVMjvhFWJMgaNJzLRSZANzAdWFrm7A8N1ie1vidQt1Dp6QldrsP 8q3fZB20SA== Received: from sim.rediris.es (mta-out04.sim.rediris.es [130.206.24.46]) by mx08-006a4e02.pphosted.com (PPS) with ESMTPS id 3tewvarrd8-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Sun, 01 Oct 2023 07:02:17 +0200 (MEST) Received: from sim.rediris.es (localhost.localdomain [127.0.0.1]) by sim.rediris.es (Postfix) with ESMTPS id 0AB0D182CCF; Sun, 1 Oct 2023 07:02:16 +0200 (CEST) Received: from localhost (localhost.localdomain [127.0.0.1]) by sim.rediris.es (Postfix) with ESMTP id 86FFB182CCC; Sun, 1 Oct 2023 07:02:15 +0200 (CEST) X-Amavis-Modified: Mail body modified (using disclaimer) - mta-out04.sim.rediris.es Received: from sim.rediris.es ([127.0.0.1]) by localhost (mta-out04.sim.rediris.es [127.0.0.1]) (amavis, port 10026) with ESMTP id qO51DSuhuoLH; Sun, 1 Oct 2023 07:02:14 +0200 (CEST) Received: from gp-workstation.iram.es (haproxy01.sim.rediris.es [130.206.24.69]) by sim.rediris.es (Postfix) with ESMTPA id 96282180084; Sun, 1 Oct 2023 07:01:58 +0200 (CEST) Date: Sun, 1 Oct 2023 07:01:56 +0200 From: Gabriel Paubert To: Steve French Cc: David Howells , Latchesar Ionkov , "Rafael J . Wysocki" , "Darrick J. Wong" , Anders Larsen , Carlos Llamas , Sven Schnelle , Mattia Dongili , Yonghong Song , Alexander Gordeev , Christoph Hellwig , Mike Marshall , Paulo Alcantara , Jason Gunthorpe , James Morris , Christian Borntraeger , devel@lists.orangefs.org, Shyam Prasad N , Jan Harkes , linux-um@lists.infradead.org, Nicholas Piggin , Alexander Viro , Eric Van Hensbergen , Suren Baghdasaryan , Trond Myklebust , Anton Altaparmakov , Christian Brauner , Greg Kr oah-Hartman , Stephen Smalley , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Ronnie Sahlberg , Sergey Senozhatsky , Luis Chamberlain , Chuck Lever , Masami Hiramatsu , Jiri Olsa , Jan Kara , Tejun Heo , Andrew Morton , Linus Torvalds , Dave Kleikamp , samba-technical@lists.samba.org, Marc Dionne , Eric Dumazet , Stanislav Fomichev , linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, Paul Moore , Leon Romanovsky , Hugh Dickins , Andrii Nakryiko , codalist@coda.cs.cmu.edu, Iurii Zaikin , Namjae Jeon , linux-trace-kernel@vger.kernel.org, Todd Kjos , Vasily Gorbik , selinux@vger.kernel.org, reiserfs-devel@vger.kernel.org, Sungjong Seo , ocfs2-devel@lists.linux.dev, Yue Hu , Jaegeuk Kim , Martijn Coenen , OGAWA Hirofumi , Hao Luo , Tony Luck , Theodore Ts'o , Nicolas Pitre , linux-ntfs-dev@lists.sourceforge.net, Muchun Song , linux-f2fs-devel@lists.sourceforge.net, "Guilherme G. Piccoli" , "Eric W. Biederman" , Anna Schumaker , David Woodhouse , Brad Warrum , Mike Kravetz , linux-efi@vger.kernel.org, Martin Brandenburg , Alexei Starovoitov , platform-driver-x86@vger.kernel.or.g, Joseph Qi , Chris Mason , linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org, Joel Fernandes , Jiri Slaby , linux-afs@lists.infradead.org, Ian Kent , Naohiro Aota , Daniel Borkmann , Miklos Szeredi , linux-rdma@vger.kernel.org, coda@cs.cmu.edu, Ilpo =?iso-8859-1?Q?J=E4rvinen?= , Ilya Dryomov , Paolo Abeni , "Serge E. Hallyn" , Amir Goldstein , Kees Cook , Arnd Bergmann , autofs@vger.kernel.org, Steven Rostedt , Mark Gross , Damien Le Moal , Eric Paris , ceph-devel@vger.kernel.org, Gao Xiang , gfs2@lists.linux.dev, linux-nfs@vger.kernel.org, linux-ext4@vger.ker.nel.org, Olga Kornievskaia , Song Liu , Jeff Layton , Martin KaFai Lau , linux-xfs@vger.kernel.org, Jeremy Kerr , Bob Peterson , linux-fsdevel@vger.kernel.org, bpf@vger.kernel.org, ntfs3@lists.linux.dev, linux-erofs@lists.ozlabs.org, "David S . Miller" , Chandan Babu R , jfs-discussion@lists.sourceforge.net, Jan Kara , Neil Brown , Dominique Martinet , Christian Schoenebeck , Bob Copeland , KP Singh , David Sterba , Konstantin Komarov , linux-mm@kvack.org, Andreas Dilger , Arve =?iso-8859-1?B?SGr4bm5lduVn?= , Mikulas Patocka , Ard Biesheuvel , Anton Ivanov , Andreas Gruenbacher , Richard Weinberger , Mark Fasheh , Dai Ngo , Steve French , linux-serial@vger.kernel.org, Jakub Kicinski , Salah Triki , John Fastabend , Evgeniy Dushistov , linux-cifs@vger.kernel.org, Heiko Carstens , Chao Yu , apparmor@lists.ubuntu.com, Josef Bacik , Tom Talpey , Hans de Goede , "Tigran A. Aivazian" , David Sterba , Xiubo Li , Ryusuke Konishi , Dennis Dalessandro , John Johansen , Ritu Agarwal , Luis de Bethencourt , Netdev , v9fs@li.sts.linux.dev, linux-unionfs@vger.kernel.org, linux-security-module@vger.kernel.org, Jeffle Xu , Phillip Lougher , Johannes Berg , Johannes Thumshirn , linuxppc-dev@lists.ozlabs.org, linux-karma-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Joel Becker Subject: [OT] Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers Message-ID: <20231001050156.GA3366643@gp-workstation.iram.es> References: <20230928110554.34758-1-jlayton@kernel.org> <20230928110554.34758-2-jlayton@kernel.org> <6020d6e7-b187-4abb-bf38-dc09d8bd0f6d@app.fastmail.com> <20230928171943.GK11439@frogsfrogsfrogs> <6a6f37d16b55a3003af3f3dbb7778a367f68cd8d.camel@kernel.org> <636661.1695969129@warthog.procyon.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Content-Transfer-Encoding: quoted-printable X-Proofpoint-ORIG-GUID: 7g7M4VduddtlWYRAuFdJHm-pjLCEd0SM X-Proofpoint-GUID: 7g7M4VduddtlWYRAuFdJHm-pjLCEd0SM X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.267,Aquarius:18.0.980,Hydra:6.0.619,FMLib:17.11.176.26 definitions=2023-10-01_02,2023-09-28_03,2023-05-22_02 X-Proofpoint-Spam-Details: rule=salida_notspam policy=salida score=0 bulkscore=0 impostorscore=0 mlxlogscore=544 suspectscore=0 malwarescore=0 mlxscore=0 spamscore=0 adultscore=0 priorityscore=1501 lowpriorityscore=0 clxscore=1011 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2309180000 definitions=main-2310010040 Precedence: bulk List-ID: X-Mailing-List: linux-s390@vger.kernel.org On Sat, Sep 30, 2023 at 09:50:41AM -0500, Steve French wrote: > On Fri, Sep 29, 2023 at 3:06=E2=80=AFAM David Howells via samba-technic= al > wrote: > > > > > > Jeff Layton wrote: > > > > > Correct. We'd lose some fidelity in currently stored timestamps, bu= t as > > > Linus and Ted pointed out, anything below ~100ns granularity is > > > effectively just noise, as that's the floor overhead for calling in= to > > > the kernel. It's hard to argue that any application needs that sort= of > > > timestamp resolution, at least with contemporary hardware. > > > > Albeit with the danger of making Steve French very happy;-), would it= make > > sense to switch internally to Microsoft-style 64-bit timestamps with = their > > 100ns granularity? >=20 > 100ns granularity does seem to make sense and IIRC was used by various > DCE standards in the 90s and 2000s (not just used for SMB2/SMB3 protoco= l and > various Windows filesystems) Historically it probably comes from VMS, where system time and file timestamps were a 64 bit integer counting in 100ns units starting on MJD 2400000.5 (Nov 17th 1858). Gabriel >=20 >=20 > --=20 > Thanks, >=20 > Steve