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Sat, 30 Sep 2023 07:50:53 -0700 (PDT) MIME-Version: 1.0 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> In-Reply-To: <636661.1695969129@warthog.procyon.org.uk> From: Steve French Date: Sat, 30 Sep 2023 09:50:41 -0500 Message-ID: Subject: Re: [PATCH 86/87] fs: switch timespec64 fields in inode to discrete integers To: David Howells Cc: Jeff Layton , Latchesar Ionkov , Konstantin Komarov , "Rafael J . Wysocki" , "Darrick J. Wong" , Anders Larsen , Carlos Llamas , Andrii Nakryiko , Mattia Dongili , Hugh Dickins , John Johansen , Yonghong Song , Alexander Gordeev , Christoph Hellwig , Mike Marshall , Paulo Alcantara , linux-xfs@vger.kernel.org, Michael Ellerman , James Morris , Christophe Leroy , Christian Borntraeger , devel@lists.orangefs.org, Shyam Prasad N , linux-um@lists.infradead.org, Nicholas Piggin , Alexander Viro , Eric Van Hensbergen , Suren Baghdasaryan , Trond Myklebust , Anton Altaparmakov , Christian Brauner , Greg Kroah-Hartman , Stephen Smalley , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, Ronnie Sahlberg , Sergey Senozhatsky , =?UTF-8?B?QXJ2ZSBIasO4bm5ldsOlZw==?= , Chuck Lever , Sven Schnelle , Jiri Olsa , Jan Kara , Tejun Heo , Andrew Morton , linux-trace-kernel@vger.kernel.org, Linus Torvalds , Dave Kleikamp , linux-mm@kvack.org, Joel Fernandes , Eric Dumazet , Stanislav Fomichev , linux-s390@vger.kernel.org, linux-nilfs@vger.kernel.org, Paul Moore , Leon Romanovsky , John Fastabend , Luis Chamberlain , codalist@coda.cs.cmu.edu, Iurii Zaikin , Namjae Jeon , Masami Hiramatsu , Todd Kjos , Vasily Gorbik , selinux@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, reiserfs-devel@vger.kernel.org, Miklos Szeredi , 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" , gfs2@lists.linux.dev, "Eric W. Biederman" , Anna Schumaker , Brad Warrum , Mike Kravetz , linux-efi@vger.kernel.org, Martin Brandenburg , ocfs2-devel@lists.linux.dev, Alexei Starovoitov , platform-driver-x86@vger.kernel.org, Chris Mason , linux-mtd@lists.infradead.org, linux-hardening@vger.kernel.org, Marc Dionne , Jiri Slaby , linux-afs@lists.infradead.org, Ian Kent , Naohiro Aota , Daniel Borkmann , Dennis Dalessandro , linux-rdma@vger.kernel.org, coda@cs.cmu.edu, =?UTF-8?Q?Ilpo_J=C3=A4rvinen?= , Ilya Dryomov , Paolo Abeni , "Serge E. Hallyn" , Christian Schoenebeck , Kees Cook , Arnd Bergmann , autofs@vger.kernel.org, Steven Rostedt , Mark Gross , Damien Le Moal , Eric Paris , ceph-devel@vger.kernel.org, Gao Xiang , Jan Harkes , linux-nfs@vger.kernel.org, linux-ext4@vger.kernel.org, Olga Kornievskaia , Song Liu , samba-technical@lists.samba.org, Steve French , Jeremy Kerr , Netdev , 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 , Amir Goldstein , Bob Copeland , KP Singh , linux-unionfs@vger.kernel.org, Joseph Qi , Andreas Dilger , Mikulas Patocka , Ard Biesheuvel , Anton Ivanov , Andreas Gruenbacher , Richard Weinberger , Mark Fasheh , Dai Ngo , Jason Gunthorpe , linux-serial@vger.kernel.org, Jakub Kicinski , Salah Triki , 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 , Johannes Thumshirn , Ritu Agarwal , Luis de Bethencourt , Martin KaFai Lau , v9fs@lists.linux.dev, David Sterba , linux-security-module@vger.kernel.org, Jeffle Xu , Phillip Lougher , Johannes Berg , Sungjong Seo , David Woodhouse , linux-karma-devel@lists.sourceforge.net, linux-btrfs@vger.kernel.org, Joel Becker Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: 647AD40010 X-Stat-Signature: 3qy9nknfig73pd7ympx5rs31aarkxssp X-Rspam-User: X-HE-Tag: 1696085455-750543 X-HE-Meta: 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 YyM4rC0R 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Sep 29, 2023 at 3:06=E2=80=AFAM David Howells via samba-technical wrote: > > > Jeff Layton wrote: > > > Correct. We'd lose some fidelity in currently stored timestamps, but as > > Linus and Ted pointed out, anything below ~100ns granularity is > > effectively just noise, as that's the floor overhead for calling into > > 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 mak= e > sense to switch internally to Microsoft-style 64-bit timestamps with thei= r > 100ns granularity? 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 protocol an= d various Windows filesystems) --=20 Thanks, Steve