linux-kernel - Re: [PATCH 0/4] exportfs: add flag to allow marking export operations as only supporting file handles

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Message-ID: <Z1D2BE2S6FLJ0tTk@infradead.org>
Date: Wed, 4 Dec 2024 16:38:28 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Christian Brauner <brauner@...nel.org>
Cc: Amir Goldstein <amir73il@...il.com>, Jeff Layton <jlayton@...nel.org>,
	Erin Shepherd <erin.shepherd@....eu>,
	Chuck Lever <chuck.lever@...cle.com>, linux-fsdevel@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-nfs@...r.kernel.org,
	stable <stable@...nel.org>
Subject: Re: [PATCH 0/4] exportfs: add flag to allow marking export
 operations as only supporting file handles

On Sun, Dec 01, 2024 at 02:12:24PM +0100, Christian Brauner wrote:
> Hey,
> 
> Some filesystems like kernfs and pidfs support file handles as a
> convenience to enable the use of name_to_handle_at(2) and
> open_by_handle_at(2) but don't want to and cannot be reliably exported.
> Add a flag that allows them to mark their export operations accordingly
> and make NFS check for its presence.
> 
> @Amir, I'll reorder the patches such that this series comes prior to the
> pidfs file handle series. Doing it that way will mean that there's never
> a state where pidfs supports file handles while also being exportable.
> It's probably not a big deal but it's definitely cleaner. It also means
> the last patch in this series to mark pidfs as non-exportable can be
> dropped. Instead pidfs export operations will be marked as
> non-exportable in the patch that they are added in.

Can you please invert the polarity?  Marking something as not supporting
is always awkward.  Clearly marking it as supporting something (and
writing down in detail what is required for that) is much better, even
it might cause a little more churn initially.