linux-kernel - Re: [PATCH 00/24] vfs: require filesystems to explicitly opt-in to lease support

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Message-ID: <aWiMaMwI6nYGX9Bq@infradead.org>
Date: Wed, 14 Jan 2026 22:42:48 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Christian Brauner <brauner@...nel.org>
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Subject: Re: [PATCH 00/24] vfs: require filesystems to explicitly opt-in to
 lease support

On Wed, Jan 14, 2026 at 04:20:13PM +0100, Christian Brauner wrote:
> > You're still think of it the wrong way.  If we do have file systems
> > that break the original exportfs semantics we need to fix that, and
> > something like a "stable handles" flag will work well for that.  But
> > a totally arbitrary "is exportable" flag is total nonsense.
> 
> File handles can legitimately be conceptualized independently of
> exporting a filesystem. If we wanted to tear those concepts apart
> implementation wise we could.
> 
> It is complete nonsense to expect the kernel to support exporting any
> arbitrary internal filesystem or to not support file handles at all.

You are going even further down the path of entirely missing the point
(or the two points by now).

If a file systems meets all technical requirements of being nfsd
exportable and the users asks for it, it is not our job to make an
arbitrary policy decision to say no.

If it does not meet the technical requirements it obviously should
not be exportable.  And it seems like the spread of file handles
beyond nfs exporting created some ambiguity here, which we need to
fix.