From: "Darrick J. Wong" <djwong@kernel.org>
To: Matthew Wilcox <willy@infradead.org>
Cc: Amir Goldstein <amir73il@gmail.com>,
John Groves <john@jagalactic.com>, John Groves <John@groves.net>,
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Subject: Re: [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone)
Date: Wed, 5 Aug 2026 22:34:09 -0700 [thread overview]
Message-ID: <20260806053409.GL3560084@frogsfrogsfrogs> (raw)
In-Reply-To: <anQZdSsJSyoqJkCo@casper.infradead.org>
On Thu, Aug 06, 2026 at 06:19:49AM +0100, Matthew Wilcox wrote:
> On Mon, Aug 03, 2026 at 10:52:19AM +0200, Amir Goldstein wrote:
> > > The most important thing to know about famfs is that it CANNOT be used as a
> > > general purpose file system. It is for enabling file-based byte-level access
> > > (including direct mmap) to very large (e.g. 100TB) shared/disaggregated
> > > memory appliances - which have become available during this long process,
> > > and which are in need of Linux support.
> > >
> > > So famfs cannot be used by anybody who doesn't know why they need it; Making
> > > famfs standalone means it can't affect users who don't use it. And my super-
> > > mega-corp employer (Micron), as well as other memory companies, need it.
> > > We do not intend to abandon it, but imagine if we did: fs/famfs/ should be
> > > removed if the memory companies can't be bothered to maintain it.
> >
> > It does not work this way.
> > When vfs maintainers accept standalone famfs they accept the burden of
> > maintaining it whenever vfs internal APIs change even if the filesystem was
> > abandoned by the mega-corps.
> > That is the code of the push back for adding new filesystems.
> > Removing the fs and breaking deployed systems is not an option for the vfs
> > maintainers.
>
> Sure it is. We removed EFS just last month, because we decided that it
> wasn't worth keeping any more. Just like we removed Itanium architecture
> support (and a number of other architectures before that). We've removed
> other filesystems in the past (xiafs, ext, surely a few others).
and freevxfs just this week because the one user/complainer said hch
could let it die.
--D
> Yes, there are burdens on others by accepting this filesystem -- but if
> it's a standalone VFS filesystem, those are felt by those who work on
> the VFS. If it's part of FUSE, then it's felt by those who work on FUSE.
> And we've already determined that those who work on FUSE are even more
> overburdened than those who work on the VFS.
>
> famfs does not seem to be a natural fit for FUSE. It has needs unlike any
> other Linux filesystem, and quite possibly unlike any other filesystem
> that is to come. Rearchitecting FUSE to make famfs fit seems like a
> very dodgy proposition to me.
>
>
prev parent reply other threads:[~2026-08-06 5:34 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260803022730.75731-1-john@jagalactic.com>
2026-08-03 2:27 ` [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone) John Groves
2026-08-03 2:28 ` [PATCH V12 01/12] dax: replace exported dax_dev_get() with non-allocating dax_dev_find() John Groves
2026-08-03 2:43 ` sashiko-bot
2026-08-03 19:13 ` Alison Schofield
2026-08-05 20:21 ` John Groves
2026-08-03 2:28 ` [PATCH V12 02/12] famfs: Module operations, fs_context, and mount John Groves
2026-08-03 2:49 ` sashiko-bot
2026-08-06 4:37 ` Darrick J. Wong
2026-08-06 13:22 ` John Groves
2026-08-03 2:28 ` [PATCH V12 03/12] famfs: Add daxdev table and dax notify_failure support John Groves
2026-08-03 2:45 ` sashiko-bot
2026-08-06 5:05 ` Darrick J. Wong
2026-08-06 13:36 ` John Groves
2026-08-03 2:28 ` [PATCH V12 04/12] famfs: Introduce inode_operations and super_operations John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:12 ` Darrick J. Wong
2026-08-06 16:31 ` John Groves
2026-08-03 2:29 ` [PATCH V12 05/12] famfs: Introduce file_operations read/write John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:14 ` Darrick J. Wong
2026-08-06 20:03 ` John Groves
2026-08-03 2:29 ` [PATCH V12 06/12] famfs: Introduce mmap and VM fault handling John Groves
2026-08-03 2:46 ` sashiko-bot
2026-08-06 5:16 ` Darrick J. Wong
2026-08-06 20:40 ` John Groves
2026-08-03 2:29 ` [PATCH V12 07/12] famfs: MAP_CREATE ioctl and fmap ingest (ABI 44) John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:24 ` Darrick J. Wong
2026-08-06 20:53 ` John Groves
2026-08-03 2:29 ` [PATCH V12 08/12] famfs: iomap_begin and file-to-dax offset resolution John Groves
2026-08-03 2:44 ` sashiko-bot
2026-08-06 5:28 ` Darrick J. Wong
2026-08-06 22:14 ` John Groves
2026-08-03 2:29 ` [PATCH V12 09/12] famfs: Register secondary daxdevs by path (FAMFSIOC_DAXDEV_OPEN) John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:29 ` Darrick J. Wong
2026-08-06 22:22 ` John Groves
2026-08-03 2:29 ` [PATCH V12 10/12] famfs: Add runtime operation-permission (opts) framework John Groves
2026-08-03 2:42 ` sashiko-bot
2026-08-06 5:31 ` Darrick J. Wong
2026-08-06 22:30 ` John Groves
2026-08-03 2:30 ` [PATCH V12 11/12] famfs: Report device capacity via statfs so df works John Groves
2026-08-03 2:58 ` sashiko-bot
2026-08-06 5:33 ` Darrick J. Wong
2026-08-03 2:30 ` [PATCH V12 12/12] famfs: Add documentation John Groves
2026-08-06 5:38 ` Darrick J. Wong
2026-08-03 8:52 ` [PATCH V12 00/12] famfs: the Fabric-Attached Memory File System (standalone) Amir Goldstein
2026-08-06 5:19 ` Matthew Wilcox
2026-08-06 5:34 ` Darrick J. Wong [this message]
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