linux-kernel - Re: [PATCH 00/29] fs: require filesystems to explicitly opt-in to nfsd export support

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Message-ID: <aXCjYY9tVKWv29fN@infradead.org>
Date: Wed, 21 Jan 2026 01:58:57 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Christian Brauner <brauner@...nel.org>
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Subject: Re: [PATCH 00/29] fs: require filesystems to explicitly opt-in to
 nfsd export support

On Tue, Jan 20, 2026 at 11:31:54AM +0100, Christian Brauner wrote:
> It is very much fine for a filesystems to support file handles without
> wanting to support exporting via NFS. That is especially true for
> in-kernel pseudo filesystems.

I'm still amazed at this statement.  "Wanting to export" is not
something for the file system to decide on in any kind of sane
layering.  The file systems exports features, and layers higher
in the stack make use of it.  We just need to be precise in describing

In-kernel code will then we so nice to respect it.  But for userspace
even then all bets are off.