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From: Christoph Hellwig <hch@infradead.org>
To: cel@kernel.org
Cc: NeilBrown <neil@brown.name>, Jeff Layton <jlayton@kernel.org>,
	Olga Kornievskaia <okorniev@redhat.com>,
	Dai Ngo <dai.ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
	linux-nfs@vger.kernel.org, Chuck Lever <chuck.lever@oracle.com>,
	Roland Mainz <roland.mainz@nrubsig.org>
Subject: Re: [PATCH] NFSD: Implement FATTR4_CLONE_BLKSIZE attribute
Date: Tue, 6 May 2025 01:10:17 -0700	[thread overview]
Message-ID: <aBnD6Wj1yq9MP8ZB@infradead.org> (raw)
In-Reply-To: <20250427163914.5053-1-cel@kernel.org>

On Sun, Apr 27, 2025 at 12:39:14PM -0400, cel@kernel.org wrote:
> NFSD can return 0 here, as at least one client implementation we
> are aware of (the Linux NFS client) treats 0 as meaning "CLONE has
> no alignment restrictions".

Usuaully clone does have a restriction, though.

> Meanwhile we need to consult the nfsv4 Working Group to clarify the
> meaning and use of the value of this attribute.

Yeah, the attribute seems to be severly underspecified, i.e. it does
not even provide a unit that the value is in.

I think the only sane way out is an errate that makes 0 mean
"not specified" and then provides the byte unit and maybe some
other quirks.

> +	/* Linux filesystems have no clone alignment restrictions */

That is absolutely untrue as said above.


  reply	other threads:[~2025-05-06  8:10 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-04-27 16:39 [PATCH] NFSD: Implement FATTR4_CLONE_BLKSIZE attribute cel
2025-05-06  8:10 ` Christoph Hellwig [this message]
2025-05-06  9:31   ` Roland Mainz
2025-05-06 13:45   ` Chuck Lever
2025-05-06 13:49     ` Christoph Hellwig

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