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From: Dave Chinner <david@fromorbit.com>
To: Arnd Bergmann <arnd@arndb.de>
Cc: y2038@lists.linaro.org, linux-fsdevel@vger.kernel.org,
	Deepa Dinamani <deepa.kernel@gmail.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [Y2038] [RFC 02/15] vfs: Change all structures to support 64 bit time
Date: Fri, 15 Jan 2016 13:27:34 +1100	[thread overview]
Message-ID: <20160115022733.GL6033@dastard> (raw)
In-Reply-To: <4774139.hV6lmEpfqG@wuerfel>

On Thu, Jan 14, 2016 at 11:54:36PM +0100, Arnd Bergmann wrote:
> On Thursday 14 January 2016 23:46:16 Arnd Bergmann wrote:
> > 
> > I'm not following the line of thought here. We have some users
> > that want ext4 to mount old file system images without long
> > inodes writable, because they don't care about the 2038 problem.
> > We also have other users that want to force the same file system
> > image to be read-only because they want to ensure that it does
> > not stop working correctly when the time overflow happens while
> > the fs is mounted.
> > 
> > If you don't want a compile-time option for it, how do you suggest
> > we decide which case we have?
> 
> In case that came across wrong, I'm assuming that the first
> user also wants all the system calls enabled that pass 32-bit
> time_t values, while the second one wants them all left out from
> the kernel to ensure that no user space program gets incorrect
> data.

system call API support is a completely different class of problem.
It's out of the scope of this patchset, and really I don't care what
you do with them.

The point I'm making is that we'll have to modify all the existing
filesystem code to supply a valid timestamp range to the VFS at
mount time for the range checking/clamping, similar to how we do the
granularity specification right now. That means we can do rejection
of non-y2038k compliant filesystems at runtime based on what the
filesystem tells the VFS it supports..  Set up the default to be
reject if rw, allow if ro, and provide a mount option to override ad
allow mounting rw.

Users can then make the decision when mounting their filesystems.
If they are system/automatically mounted filesystems and aren't
y2038k compliant, then the override option can be added to
/etc/fstab and we're all good. If the truly paranoid users want to
disallow the override and/or read only mount options, then add a
sysctl to control that.

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  reply	other threads:[~2016-01-15  2:27 UTC|newest]

Thread overview: 56+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-01-07  5:35 [RFC 00/15] Add 64 bit timestamp support Deepa Dinamani
2016-01-07  5:35 ` [RFC 01/15] fs: add Kconfig entry CONFIG_FS_USES_64BIT_TIME Deepa Dinamani
2016-01-07  5:35 ` [RFC 02/15] vfs: Change all structures to support 64 bit time Deepa Dinamani
2016-01-10 23:03   ` Dave Chinner
2016-01-12  5:42     ` Deepa Dinamani
2016-01-12  8:29       ` Dave Chinner
2016-01-12  9:27         ` [Y2038] " Arnd Bergmann
2016-01-13  6:27           ` Dave Chinner
2016-01-13  9:20             ` Arnd Bergmann
2016-01-13  9:20               ` Arnd Bergmann
2016-01-13 16:33         ` Deepa Dinamani
2016-01-13 21:04           ` Dave Chinner
2016-01-14 16:53             ` [Y2038] " Arnd Bergmann
2016-01-14 18:00               ` Deepa Dinamani
2016-01-14 21:00               ` Dave Chinner
2016-01-14 22:46                 ` Arnd Bergmann
2016-01-14 22:54                   ` Arnd Bergmann
2016-01-15  2:27                     ` Dave Chinner [this message]
2016-01-15 17:01                       ` Arnd Bergmann
2016-01-15 22:41                         ` Dave Chinner
2016-01-15  2:49                   ` Dave Chinner
2016-01-15 16:50                     ` Arnd Bergmann
2016-01-16 19:14                       ` Andreas Dilger
2016-01-16 23:36                         ` Arnd Bergmann
2016-01-17  2:30                           ` Andreas Dilger
2016-01-18  6:09                             ` Deepa Dinamani
2016-01-18 10:56                               ` Arnd Bergmann
2016-01-18 17:40                                 ` Deepa Dinamani
2016-01-18 19:53                                   ` Arnd Bergmann
2016-01-18 21:14                                     ` Dave Chinner
2016-01-18 21:46                                       ` Arnd Bergmann
2016-01-19  1:38                                         ` Dave Chinner
2016-01-19  5:27                                           ` Deepa Dinamani
2016-01-19 20:49                                             ` Dave Chinner
2016-01-19 22:25                                               ` Arnd Bergmann
2016-01-20  5:12                                                 ` Deepa Dinamani
2016-01-20 15:04                                                   ` Deepa Dinamani
2016-01-20 23:06                                                 ` Dave Chinner
2016-01-20 23:17                                                   ` [Y2038] " Arnd Bergmann
2016-01-27  6:26                                                     ` Deepa Dinamani
2016-01-15  5:03                 ` Deepa Dinamani
2016-01-07  5:36 ` [RFC 03/15] kernel: time: Add macros and functions " Deepa Dinamani
2016-01-07  5:36 ` [RFC 04/15] vfs: Add support for vfs code to use " Deepa Dinamani
2016-01-07  5:36 ` [RFC 05/15] fs: cifs: Add support for cifs " Deepa Dinamani
2016-01-07  5:36 ` [RFC 06/15] fs: fat: convert fat to " Deepa Dinamani
2016-01-07  5:36 ` [RFC 07/15] fs: ext4: convert to use " Deepa Dinamani
2016-01-07  5:36 ` [RFC 08/15] fs: Enable " Deepa Dinamani
2016-01-07  5:36 ` [RFC 09/15] fs: cifs: replace inode_timespec with timespec64 Deepa Dinamani
2016-01-07  5:36 ` [RFC 10/15] fs: fat: " Deepa Dinamani
2016-01-07  5:36 ` [RFC 11/15] fs: ext4: " Deepa Dinamani
2016-01-07  5:36 ` [RFC 12/15] vfs: remove inode_timespec and timespec references Deepa Dinamani
2016-01-07  5:36 ` [RFC 13/15] kernel: time: change inode_timespec to timespec64 Deepa Dinamani
2016-01-07  8:50   ` Michael Adam
2016-01-07 10:42     ` Deepa Dinamani
2016-01-07  5:36 ` [RFC 14/15] vfs: Remove inode_timespec aliases Deepa Dinamani
2016-01-07  5:36 ` [RFC 15/15] fs: Drop CONFIG_FS_USES_64BIT_TIME Deepa Dinamani

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