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From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Deepa Dinamani <deepa.kernel@gmail.com>
Cc: "Darrick J. Wong" <darrick.wong@oracle.com>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux FS-devel Mailing List <linux-fsdevel@vger.kernel.org>,
	Arnd Bergmann <arnd@arndb.de>,
	y2038 Mailman List <y2038@lists.linaro.org>,
	Andreas Dilger <adilger.kernel@dilger.ca>,
	linux-ext4@vger.kernel.org
Subject: Re: [PATCH 09/20] ext4: Initialize timestamps limits
Date: Thu, 1 Aug 2019 18:43:44 -0400	[thread overview]
Message-ID: <20190801224344.GC17372@mit.edu> (raw)
In-Reply-To: <CABeXuvpiom9eQi0y7PAwAypUP1ezKKRfbh-Yqr8+Sbio=QtUJQ@mail.gmail.com>

On Thu, Aug 01, 2019 at 12:18:28PM -0700, Deepa Dinamani wrote:
> > Say you have a filesystem with s_inode_size > 128 where not all of the
> > ondisk inodes have been upgraded to i_extra_isize > 0 and therefore
> > don't support nanoseconds or times beyond 2038.  I think this happens on
> > ext3 filesystems that reserved extra space for inode attrs that are
> > subsequently converted to ext4?
> 
> I'm confused about ext3 being converted to ext4. If the converted
> inodes have extra space, then ext4_iget() will start using the extra
> space when it modifies the on disk inode, won't it?i

It is possible that you can have an ext3 file system with (for
example) 256 byte inodes, and all of the extra space was used for
extended attributes, then ext4 won't have the extra space available.
This is going toh be on an inode-by-inode basis, and if an extended
attribute is motdified or deleted, the space would become available,t
and then inode would start getting a higher resolution timestamp.

I really don't think it's worth worrying about that, though.  It's
highly unlikely ext3 file systems will be still be in service by the
time it's needed in 2038.  And if so, it's highly unlikely they would
be converted to ext4.

						- Ted

  reply	other threads:[~2019-08-01 22:44 UTC|newest]

Thread overview: 62+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-07-30  1:49 [PATCH 00/20] vfs: Add support for timestamp limits Deepa Dinamani
2019-07-30  1:49 ` [PATCH 01/20] vfs: Add file timestamp range support Deepa Dinamani
2019-07-30  1:49 ` [PATCH 02/20] vfs: Add timestamp_truncate() api Deepa Dinamani
2019-07-30  1:49 ` [PATCH 03/20] timestamp_truncate: Replace users of timespec64_trunc Deepa Dinamani
2019-07-30  8:27   ` OGAWA Hirofumi
2019-07-30 17:26     ` Deepa Dinamani
2019-07-30 22:28       ` Anton Altaparmakov
2019-07-31  0:08         ` Deepa Dinamani
2019-07-30  1:49 ` [PATCH 04/20] mount: Add mount warning for impending timestamp expiry Deepa Dinamani
2019-08-05 14:12   ` [Y2038] " Ben Hutchings
2019-08-05 14:40     ` Arnd Bergmann
2019-08-10 20:47     ` Deepa Dinamani
2019-08-05 14:14   ` Ben Hutchings
2019-08-10 20:44     ` Deepa Dinamani
2019-08-12 13:25       ` Ben Hutchings
2019-08-12 14:11         ` Arnd Bergmann
2019-08-12 16:09           ` Deepa Dinamani
2019-08-12 16:15             ` Deepa Dinamani
2019-08-12 17:43               ` Ben Hutchings
2019-07-30  1:49 ` [PATCH 05/20] utimes: Clamp the timestamps before update Deepa Dinamani
2019-07-31 15:14   ` Darrick J. Wong
2019-07-31 15:33     ` Deepa Dinamani
2019-08-05 13:30   ` [Y2038] " Ben Hutchings
2019-08-10 20:36     ` Deepa Dinamani
2019-07-30  1:49 ` [PATCH 06/20] fs: Fill in max and min timestamps in superblock Deepa Dinamani
2019-07-31 15:28   ` Darrick J. Wong
2019-07-30  1:49 ` [PATCH 07/20] 9p: Fill min and max timestamps in sb Deepa Dinamani
2019-07-30  1:49 ` [PATCH 08/20] adfs: Fill in max and min " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 09/20] ext4: Initialize timestamps limits Deepa Dinamani
2019-07-31 15:26   ` Darrick J. Wong
2019-08-01 19:18     ` Deepa Dinamani
2019-08-01 22:43       ` Theodore Y. Ts'o [this message]
2019-08-02 10:39         ` Arnd Bergmann
2019-08-02 15:43           ` Theodore Y. Ts'o
2019-08-02 19:00             ` Arnd Bergmann
2019-08-02 21:39               ` Theodore Y. Ts'o
2019-08-03  9:30                 ` Arnd Bergmann
2019-08-03 16:02                   ` Theodore Y. Ts'o
2019-08-03 20:24                     ` Arnd Bergmann
2019-08-07 18:04                       ` Andreas Dilger
2019-08-08 18:27                         ` Deepa Dinamani
2019-07-30  1:49 ` [PATCH 10/20] fs: nfs: Initialize filesystem timestamp ranges Deepa Dinamani
2019-07-30  1:49 ` [PATCH 11/20] fs: cifs: " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 12/20] fs: fat: " Deepa Dinamani
2019-07-30  9:31   ` OGAWA Hirofumi
2019-07-30 17:39     ` Deepa Dinamani
2019-07-31  0:48       ` OGAWA Hirofumi
2019-07-30  1:49 ` [PATCH 13/20] fs: affs: " Deepa Dinamani
2019-08-01 11:28   ` David Sterba
2019-07-30  1:49 ` [PATCH 14/20] fs: sysv: " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 15/20] fs: ceph: " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 16/20] fs: orangefs: " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 17/20] fs: hpfs: " Deepa Dinamani
2019-07-30  1:49 ` [PATCH 18/20] fs: omfs: " Deepa Dinamani
2019-07-30 14:25   ` Bob Copeland
2019-07-30  1:49 ` [PATCH 19/20] pstore: fs superblock limits Deepa Dinamani
2019-07-30  4:31   ` Kees Cook
2019-07-30  7:36     ` Arnd Bergmann
2019-08-02  2:26       ` Deepa Dinamani
2019-08-02  7:15         ` Arnd Bergmann
2019-08-18 14:00           ` Deepa Dinamani
2019-07-30  1:49 ` [PATCH 20/20] isofs: Initialize filesystem timestamp ranges Deepa Dinamani

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