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Date: Mon, 29 Apr 2024 19:32:55 +0100
From: Matthew Wilcox <willy@infradead.org>
To: John Groves <John@groves.net>
Cc: Jonathan Corbet <corbet@lwn.net>,
	Jonathan Cameron <Jonathan.Cameron@huawei.com>,
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	Stanislav Fomichev <sdf@google.com>,
	Dongsheng Yang <dongsheng.yang@easystack.cn>
Subject: Re: [RFC PATCH v2 00/12] Introduce the famfs shared-memory file
 system
Message-ID: <Zi_n15gvA89rGZa_@casper.infradead.org>
References: <cover.1714409084.git.john@groves.net>
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In-Reply-To: <cover.1714409084.git.john@groves.net>

On Mon, Apr 29, 2024 at 12:04:16PM -0500, John Groves wrote:
> This patch set introduces famfs[1] - a special-purpose fs-dax file system
> for sharable disaggregated or fabric-attached memory (FAM). Famfs is not
> CXL-specific in anyway way.
> 
> * Famfs creates a simple access method for storing and sharing data in
>   sharable memory. The memory is exposed and accessed as memory-mappable
>   dax files.
> * Famfs supports multiple hosts mounting the same file system from the
>   same memory (something existing fs-dax file systems don't do).

Yes, but we do already have two filesystems that support shared storage,
and are rather more advanced than famfs -- GFS2 and OCFS2.  What are
the pros and cons of improving either of those to support DAX rather
than starting again with a new filesystem?