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From: Byron Stanoszek <>
To: Dave Chinner <>
Cc: Jan Kara <>, Matthew Wilcox <>,,,
Subject: Re: Is it time to remove reiserfs?
Date: Wed, 23 Feb 2022 09:48:26 -0500 (EST)	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <20220222221614.GC3061737@dread.disaster.area>

On Wed, 23 Feb 2022, Dave Chinner wrote:
> On Tue, Feb 22, 2022 at 11:04:08AM +0100, Jan Kara wrote:
>> Hello!
>> On Sun 20-02-22 12:13:04, Matthew Wilcox wrote:
>>> Keeping reiserfs in the tree has certain costs.  For example, I would
>>> very much like to remove the 'flags' argument to ->write_begin.  We have
>>> the infrastructure in place to handle AOP_FLAG_NOFS differently, but
>>> AOP_FLAG_CONT_EXPAND is still around, used only by reiserfs.
>>> Looking over the patches to reiserfs over the past couple of years, there
>>> are fixes for a few syzbot reports and treewide changes.  There don't
>>> seem to be any fixes for user-spotted bugs since 2019.  Does reiserfs
>>> still have a large install base that is just very happy with an old
>>> stable filesystem?  Or have all its users migrated to new and exciting
>>> filesystems with active feature development?
>>> We've removed support for senescent filesystems before (ext, xiafs), so
>>> it's not unprecedented.  But while I have a clear idea of the benefits to
>>> other developers of removing reiserfs, I don't have enough information to
>>> weigh the costs to users.  Maybe they're happy with having 5.15 support
>>> for their reiserfs filesystems and can migrate to another filesystem
>>> before they upgrade their kernel after 5.15.
>>> Another possibility beyond outright removal would be to trim the kernel
>>> code down to read-only support for reiserfs.  Most of the quirks of
>>> reiserfs have to do with write support, so this could be a useful way
>>> forward.  Again, I don't have a clear picture of how people actually
>>> use reiserfs, so I don't know whether it is useful or not.
>>> NB: Please don't discuss the personalities involved.  This is purely a
>>> "we have old code using old APIs" discussion.
>> So from my distro experience installed userbase of reiserfs is pretty small
>> and shrinking. We still do build reiserfs in openSUSE / SLES kernels but
>> for enterprise offerings it is unsupported (for like 3-4 years) and the module
>> is not in the default kernel rpm anymore.
>> So clearly the filesystem is on the deprecation path, the question is
>> whether it is far enough to remove it from the kernel completely. Maybe
>> time to start deprecation by printing warnings when reiserfs gets mounted
>> and then if nobody yells for year or two, we'll go ahead and remove it?
> Yup, I'd say we should deprecate it and add it to the removal
> schedule. The less poorly tested legacy filesystem code we have to
> maintain the better.
> Along those lines, I think we really need to be more aggressive
> about deprecating and removing filesystems that cannot (or will not)
> be made y2038k compliant in the new future. We're getting to close
> to the point where long term distro and/or product development life
> cycles will overlap with y2038k, so we should be thinking of
> deprecating and removing such filesystems before they end up in
> products that will still be in use in 15 years time.
> And just so everyone in the discussion is aware: XFS already has a
> deprecation and removal schedule for the non-y2038k-compliant v4
> filesystem format. It's officially deprecated right now, we'll stop
> building kernels with v4 support enabled by default in 2025, and
> we're removing the code that supports the v4 format entirely in
> 2030.

For what it's worth, I have a number of production servers still using
Reiserfs, which I regularly maintain by upgrading to the latest Linux kernel
annually (mostly to apply security patches). I figured this filesystem would
still be available for several more years, since it's not quite y2038k yet.

I originally installed Reiserfs on these systems as early as 2005 due to the
tail-packing feature, which saved space with many small files on older
harddrives. Since then, I witnessed the development of ext4, and then btrfs.
For a long time, these newer filesystems had occasional reports of instabilities
and lost data, and so I shied away from using them. Meanwhile, Reiserfs reached
a level of maturity and no longer had active development on it, except for the
occasional bugfix. I felt this was a filesystem I could trust going forward
(despite its relative slowness), even after popular Linux distributions
eventually dropped it from being installed by default.

I have only recently begun to use XFS on newer installs, only since the XFS
developers added bigtime support for y2038k. But for existing installs, I ask
that we keep Reiserfs supported in the kernel a little longer. Perhaps use the
same deprecation schedule that was picked for XFS v4 (roughly 10 years of
deprecation before eventual removal)?


  reply	other threads:[~2022-02-23 14:54 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-20 12:13 Is it time to remove reiserfs? Matthew Wilcox
2022-02-20 23:21 ` Edward Shishkin
2022-02-20 23:22   ` [PATCH] reiserfs: get rid of AOP_FLAG_CONT_EXPAND flag Edward Shishkin
2022-02-22 10:27     ` Jan Kara
2022-02-22 13:38       ` Matthew Wilcox
2022-02-23 12:17         ` Jan Kara
2022-02-22 10:04 ` Is it time to remove reiserfs? Jan Kara
2022-02-22 22:16   ` Dave Chinner
2022-02-23 14:48     ` Byron Stanoszek [this message]
2022-02-23 15:28       ` Byron Stanoszek
2022-03-17  8:53         ` Thomas Dreibholz
2022-03-17  9:43           ` Jan Kara
2022-02-24  8:46       ` Jan Kara
2022-02-24 14:24         ` Byron Stanoszek
2022-02-24 21:06       ` Matthew Wilcox
2022-02-25 13:10         ` Byron Stanoszek
2022-02-25 13:23           ` Willy Tarreau
2022-02-25 22:56             ` Dave Chinner
2022-02-26  0:00               ` Theodore Ts'o
2022-04-02 10:57     ` Pavel Machek
2022-04-05 23:04       ` Dave Chinner
2022-04-02 10:54   ` Pavel Machek
2022-04-04  8:55     ` Jan Kara
2022-04-04 10:07       ` Pavel Machek
2022-04-04 10:18         ` Willy Tarreau
2022-04-04 10:58           ` Pavel Machek
2022-04-04 13:05             ` Jan Kara
2022-04-04 12:55           ` Jan Kara
2022-04-04 13:16             ` Willy Tarreau

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