From: "H. Peter Anvin" Subject: Re: [RFC 00/32] making inode time stamps y2038 ready Date: Mon, 02 Jun 2014 14:57:26 -0700 Message-ID: <538CF346.2070504@zytor.com> References: <1401480116-1973111-1-git-send-email-arnd@arndb.de> <4233989.Saca0ocOUr@wuerfel> <538CCFDE.2010107@zytor.com> <7175692.dpgYFMbTaP@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Cc: "Joseph S. Myers" , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arch-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, john.stultz-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, hch-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org, tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org, geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.org, lftan-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org, linux-fsdevel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ceph-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, cluster-devel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org, coda-ETDLCGt7PQU3uPMLIKxrzw@public.gmane.org, codalist-ySnCqBnJi5yMVn35/9/JlcWGCVk0P7UB@public.gmane.org, fuse-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-afs-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-btrfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-cifs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ext4-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-f2fs-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-mtd-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-ntfs-dev-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, linux-scsi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, logfs-PCqxUs/MD9bYtjvyW6yDsg@public.gmane.org, ocfs2-devel-N0ozoZBvEnrZJqsBc5GL+g@public.gmane.org, reiserfs-devel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, samba-technical-w/Ol4Ecudpl8XjKLYN78aQ@public.gmane.org, xfs-VZNHf3L845pBDgjK7y7TUQ@public.gmane.org To: Arnd Bergmann Return-path: In-Reply-To: <7175692.dpgYFMbTaP@wuerfel> Sender: linux-cifs-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-ext4.vger.kernel.org On 06/02/2014 12:55 PM, Arnd Bergmann wrote: >> >> The bit that is really going to hurt is every single ioctl that uses a >> timespec. >> >> Honestly, though, I really don't understand the point with "struct >> inode_time". It seems like the zeroeth-order thing is to change the >> kernel internal version of struct timespec to have a 64-bit time... it >> isn't just about inodes. We then should be explicit about the external >> uses of time, and use accessors. > > I picked these because they are fairly isolated from all other uses, > in particular since inode times are the only things where we really > care about times in the distant past or future (decades away as opposed > to things that happened between boot and shutdown). > If nothing else, I would expect to be able to set the system time to weird values for testing. So I'm not so sure I agree with that... > For other kernel-internal uses, we may be better off migrating to > a completely different representation, such as nanoseconds since > boot or the architecture specific ktime_t, but this is really something > to decide for each subsystem. Having a bunch of different time representations in the kernel seems like a real headache... -hpa