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

From: Christoph Hellwig <hch@infradead.org>
To: NeilBrown <neil@brown.name>
Cc: Jeff Layton <jlayton@kernel.org>,
	Amir Goldstein <amir73il@gmail.com>,
	Christian Brauner <brauner@kernel.org>,
	Alexander Viro <viro@zeniv.linux.org.uk>,
	Chuck Lever <chuck.lever@oracle.com>,
	Olga Kornievskaia <okorniev@redhat.com>,
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	Hugh Dickins <hughd@google.com>,
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Subject: Re: [PATCH 00/29] fs: require filesystems to explicitly opt-in to nfsd export support
Date: Sun, 18 Jan 2026 22:41:04 -0800	[thread overview]
Message-ID: <aW3SAKIr_QsnEE5Q@infradead.org> (raw)
In-Reply-To: <176877859306.16766.15009835437490907207@noble.neil.brown.name>

On Mon, Jan 19, 2026 at 10:23:13AM +1100, NeilBrown wrote:
> > This was Chuck's suggested name. His point was that STABLE means that
> > the FH's don't change during the lifetime of the file.
> > 
> > I don't much care about the flag name, so if everyone likes PERSISTENT
> > better I'll roll with that.
> 
> I don't like PERSISTENT.
> I'd rather call a spade a spade.
> 
>   EXPORT_OP_SUPPORTS_NFS_EXPORT
> or
>   EXPORT_OP_NOT_NFS_COMPATIBLE
> 
> The issue here is NFS export and indirection doesn't bring any benefits.

No, it absolutely is not.  And the whole concept of calling something
after the initial or main use is a recipe for a mess.

Pick a name that conveys what the flag is about, and document those
semantics well.  This flag is about the fact that for a given file,
as long as that file exists in the file system the handle is stable.
Both stable and persistent are suitable for that, nfs is everything
but.

Remember nfs also support volatile file handles, and other applications
might rely on this (I know of quite a few user space applications that
do, but they are kinda hardwired to xfs anyway).