From: Arnd Bergmann <arnd@arndb.de>
To: "Theodore Ts'o" <tytso@mit.edu>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>,
"H. Peter Anvin" <hpa@zytor.com>,
Dave Chinner <david@fromorbit.com>,
linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
joseph@codesourcery.com, john.stultz@linaro.org,
hch@infradead.org, tglx@linutronix.de, geert@linux-m68k.org,
lftan@altera.com, linux-fsdevel@vger.kernel.org, xfs@oss.sgi.com
Subject: Re: [RFC 11/32] xfs: convert to struct inode_time
Date: Mon, 02 Jun 2014 17:01:20 +0200 [thread overview]
Message-ID: <5896675.3VErDJM7s2@wuerfel> (raw)
In-Reply-To: <20140602130700.GC14276@thunk.org>
On Monday 02 June 2014 09:07:00 Theodore Ts'o wrote:
> Yes, there are some ongoing dicussions about changing the post-2038
> encoding of the timestamp in ext4, which is why this hasn't been fixed
> yet. The main thing that's been missing is time for me to review the
> patches, and a good way of writing regression tests that will work (or
> at least not fail) on build environments with a 32-bit time_t and
> 32-bit-only capable versions of functions such as gmtime(3).
>
> And given current discussions, I may want to think about some kind of
> superblock flag to allow the use of a 32-bit unsigned encoding for
> file systems using a 128-byte inode, with a way of setting that flag
> after scanning the file system to make sure there are no times that
> are previous to January 1, 1970. (Or more generally, allow any epoch
> to be defined using a 64-bit time_t offset stored in the superblock...)
FWIW, I've gone through the other file system implementations once
more. The most common pattern I've encountered is to have a read_inode
function with
inode->i_mtime = le32_to_cpu(raw_inode->mtime);
which results in interpreting the time as 'signed' on 32-bit
kernels, but as 'unsigned' on 64-bit kernels. This could have been
done intentionally to extend the valid time range to 2106 on 64-bit
kernels, but it seems more likely that the code was written with
no thought given to 64-bit time_t at all. I see this pattern on
p9fs (old protocol only), afs, bfs, ceph, efs, freevxfs, hpfs, jffs2,
jfs, minix, nfsv2/v3 (this was clearly intentional and is
spelled out in the RFC), qnx4, qnx6, reiserfs, squashfs, sysv,
and ufs (protocol version 1 only).
The other behavior I see is to treat the on-disk 32-bit value
as signed on both 32-bit and 64-bit kernels:
inode->i_mtime = (signed)le32_to_cpu(raw_inode->mtime);
this seems to be done intentionally in all cases, to maintain
compatibility between 32-bit and 64-bit kernels, but it's
relatively rare: exofs, ext2/3/4 (good old inodes) and xfs
are the only ones doing this.
In case of ext2/3/4, the sign handlign was introduced here:
http://www.spinics.net/lists/linux-ext4/msg01758.html
exofs and xfs seem to have done it like this for all of git
history.
Arnd
next prev parent reply other threads:[~2014-06-02 15:03 UTC|newest]
Thread overview: 124+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-30 20:01 [RFC 00/32] making inode time stamps y2038 ready Arnd Bergmann
2014-05-30 20:01 ` [RFC 01/32] fs: introduce new 'struct inode_time' Arnd Bergmann
2014-05-31 7:56 ` Geert Uytterhoeven
2014-05-31 8:39 ` Andreas Schwab
2014-05-31 13:19 ` Geert Uytterhoeven
2014-05-31 13:46 ` Andreas Schwab
2014-05-31 14:54 ` Arnd Bergmann
2014-05-31 16:15 ` Geert Uytterhoeven
2014-05-31 9:03 ` H. Peter Anvin
2014-05-31 14:53 ` Arnd Bergmann
2014-05-31 14:55 ` H. Peter Anvin
2014-05-30 20:01 ` [RFC 02/32] uapi: add struct __kernel_timespec{32,64} Arnd Bergmann
2014-05-30 20:18 ` H. Peter Anvin
2014-05-31 15:09 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 03/32] fs: introduce sys_utimens64at Arnd Bergmann
2014-05-31 9:22 ` Andreas Schwab
2014-05-31 14:55 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 04/32] fs: introduce sys_newfstat64/sys_newfstatat64 Arnd Bergmann
2014-05-30 20:01 ` [RFC 05/32] arch: hook up new stat and utimes syscalls Arnd Bergmann
2014-05-30 20:01 ` [RFC 06/32] isofs: fix timestamps beyond 2027 Arnd Bergmann
2014-05-31 7:59 ` Geert Uytterhoeven
2014-05-31 8:47 ` H. Peter Anvin
2014-05-30 20:01 ` [RFC 07/32] fs/nfs: convert to struct inode_time Arnd Bergmann
2014-05-30 20:01 ` [RFC 08/32] fs/ceph: convert to 'struct inode_time' Arnd Bergmann
2014-05-30 20:01 ` [RFC 09/32] fs/pstore: convert to struct inode_time Arnd Bergmann
2014-05-30 21:14 ` Kees Cook
2014-05-30 20:01 ` [RFC 10/32] fs/coda: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 11/32] xfs: " Arnd Bergmann
2014-05-31 0:37 ` Dave Chinner
2014-05-31 0:41 ` H. Peter Anvin
2014-05-31 1:14 ` Dave Chinner
2014-05-31 1:22 ` H. Peter Anvin
2014-05-31 5:54 ` Dave Chinner
2014-05-31 8:41 ` H. Peter Anvin
2014-05-31 15:46 ` Nicolas Pitre
2014-06-01 19:56 ` Arnd Bergmann
2014-06-01 20:26 ` H. Peter Anvin
2014-06-02 11:02 ` Arnd Bergmann
2014-06-02 1:36 ` Nicolas Pitre
2014-06-02 2:22 ` Dave Chinner
2014-06-02 7:09 ` Geert Uytterhoeven
2014-06-02 10:56 ` Arnd Bergmann
2014-06-02 11:57 ` Theodore Ts'o
2014-06-02 12:38 ` Arnd Bergmann
2014-06-02 13:15 ` Theodore Ts'o
2014-06-02 12:52 ` Arnd Bergmann
2014-06-02 13:07 ` Theodore Ts'o
2014-06-02 15:01 ` Arnd Bergmann [this message]
2014-06-02 14:52 ` H. Peter Anvin
2014-06-02 15:04 ` Chuck Lever
2014-06-02 15:31 ` Theodore Ts'o
2014-06-02 17:12 ` H. Peter Anvin
2014-06-02 18:50 ` Arnd Bergmann
2014-06-02 22:29 ` Theodore Ts'o
2014-06-02 22:32 ` H. Peter Anvin
2014-06-02 23:32 ` Theodore Ts'o
2014-06-02 23:33 ` H. Peter Anvin
2014-06-03 13:09 ` Roger Willcocks
2014-06-02 18:52 ` Arnd Bergmann
2014-06-02 18:58 ` Roger Willcocks
2014-06-02 19:04 ` Chuck Lever
2014-06-02 19:10 ` Arnd Bergmann
2014-06-01 0:39 ` Dave Chinner
2014-06-02 14:00 ` Joseph S. Myers
2014-05-31 15:37 ` Arnd Bergmann
2014-06-01 0:24 ` Dave Chinner
2014-06-02 0:28 ` Dave Chinner
2014-06-02 11:35 ` Roger Willcocks
2014-06-02 11:43 ` Arnd Bergmann
2014-06-03 0:32 ` Dave Chinner
2014-06-03 7:33 ` Arnd Bergmann
2014-06-03 8:41 ` Dave Chinner
2014-06-03 9:16 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 12/32] btrfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 13/32] ext3: " Arnd Bergmann
2014-05-31 9:10 ` H. Peter Anvin
2014-05-31 14:32 ` Arnd Bergmann
2014-05-30 20:01 ` [RFC 14/32] ext4: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 15/32] cifs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 16/32] ntfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 17/32] ubifs: " Arnd Bergmann
2014-06-02 7:54 ` Artem Bityutskiy
2014-05-30 20:01 ` [RFC 18/32] ocfs2: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 19/32] fs/fat: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 20/32] afs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 21/32] udf: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 22/32] fs: convert simple fs to inode_time Arnd Bergmann
2014-05-30 23:06 ` Greg Kroah-Hartman
2014-05-30 20:01 ` [RFC 23/32] logfs: convert to struct inode_time Arnd Bergmann
2014-05-30 20:01 ` [RFC 24/32] hfs, hfsplus: " Arnd Bergmann
2014-05-31 14:23 ` Vyacheslav Dubeyko
2014-05-30 20:01 ` [RFC 25/32] gfs2: " Arnd Bergmann
2014-06-02 9:52 ` Steven Whitehouse
2014-05-30 20:01 ` [RFC 26/32] reiserfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 27/32] jffs2: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 28/32] adfs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 29/32] f2fs: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 30/32] fuse: " Arnd Bergmann
2014-05-30 20:01 ` [RFC 31/32] scsi: fnic: use current_kernel_time() for timestamp Arnd Bergmann
2014-05-30 20:01 ` [RFC 32/32] fs: use new inode_time definition unconditionally Arnd Bergmann
2014-05-31 14:30 ` [RFC 00/32] making inode time stamps y2038 ready Vyacheslav Dubeyko
2014-06-03 12:21 ` Arnd Bergmann
2014-05-31 14:51 ` Richard Cochran
2014-05-31 15:23 ` Arnd Bergmann
2014-05-31 18:22 ` Richard Cochran
2014-05-31 19:34 ` H. Peter Anvin
2014-06-01 4:46 ` Richard Cochran
2014-06-01 4:44 ` Richard Cochran
2014-06-02 13:52 ` Joseph S. Myers
2014-06-02 19:19 ` Arnd Bergmann
2014-06-02 19:26 ` H. Peter Anvin
2014-06-02 19:55 ` Arnd Bergmann
2014-06-02 21:57 ` H. Peter Anvin
2014-06-03 14:22 ` Arnd Bergmann
2014-06-03 14:33 ` Joseph S. Myers
2014-06-03 14:37 ` Arnd Bergmann
2014-06-03 21:38 ` Dave Chinner
2014-06-04 15:03 ` Arnd Bergmann
2014-06-04 17:30 ` Nicolas Pitre
2014-06-04 19:24 ` Arnd Bergmann
2014-06-05 0:10 ` H. Peter Anvin
2014-06-10 9:54 ` Arnd Bergmann
2014-06-02 21:02 ` Joseph S. Myers
2014-06-04 15:05 ` Arnd Bergmann
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5896675.3VErDJM7s2@wuerfel \
--to=arnd@arndb.de \
--cc=david@fromorbit.com \
--cc=geert@linux-m68k.org \
--cc=hch@infradead.org \
--cc=hpa@zytor.com \
--cc=john.stultz@linaro.org \
--cc=joseph@codesourcery.com \
--cc=lftan@altera.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=nicolas.pitre@linaro.org \
--cc=tglx@linutronix.de \
--cc=tytso@mit.edu \
--cc=xfs@oss.sgi.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).