From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 886C7146A69 for ; Fri, 5 Jul 2024 14:15:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720188947; cv=none; b=AgHRMm15yhbt9GigbOdsbT0qAJJkXtuawgX2qaGoyIVye7qjDcZd0mxNb1zYdt5tz2iscSBFjQNTRZo46ReUWKf+B4+872rq2IwbtbvAaW6zXQgiWLwyW48BtqKYfvFFwXNBqxoqZE1FkyH7/1Rk9Y0CrjGD6U0MDcUlR6oDuEw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1720188947; c=relaxed/simple; bh=1T/Trj9bwCworsC2SIOFCU683E2UnRW2hVO161Txw8Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=N1Jd62BTeA/ZUX2icIDhfBX45Akc3CtWcFKGSSbMUCHYDMXc6wtcBJMQW8h+tC8sbtbb3cGLmSTT4v14DcfYNbJp0GieyUXmDwBlgZwLwJHofdMcNNen4Q+6MI8wR780R7Pidhr6g8Ivhsp7jXu6vQImdM1o23blbRzmAEYgGLs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Cryv6cZP; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Cryv6cZP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2B673C116B1; Fri, 5 Jul 2024 14:15:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1720188947; bh=1T/Trj9bwCworsC2SIOFCU683E2UnRW2hVO161Txw8Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Cryv6cZP3fZevG8kpm6htYncTuaWsOrmGmhwLiADDw/QU9h1v3eiczVA04gKsVfRu PGXjs4gt3sp+NEtryWjH+2jFalMCt0kIbuj/Zh3kSKf+qWH+cjK+V+5iu6LCSkaiit AgMGSoYumivco3F3BIrHMOuS/z7GUbUteO67kw4wFOT9yftduk38rxmpE9lJWfapjq QMCW299PyiMugpK0TRiG7oLyVGocwkTU8iwB8uezmfk/ULcoo9R2DZR4LgFirHnnfi B7lGUtuFDSLnT7S7OYvIIjI4R8d9YsQHdiEbo64xSC9a+nnNkaud3PTqJEJrxdMqYJ kuCiM9MNwIslg== Date: Fri, 5 Jul 2024 10:15:46 -0400 From: Mike Snitzer To: Chuck Lever III Cc: Christoph Hellwig , Jeff Layton , Linux NFS Mailing List , Anna Schumaker , Trond Myklebust , Neil Brown , Dave Chinner Subject: Re: [PATCH v11 00/20] nfs/nfsd: add support for localio Message-ID: References: <4486ee80a487c174ec88c7e12705d99e22ae812a.camel@kernel.org> <57C1CB2B-3B46-48F3-A095-417845001C3E@oracle.com> Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <57C1CB2B-3B46-48F3-A095-417845001C3E@oracle.com> On Fri, Jul 05, 2024 at 01:35:18PM +0000, Chuck Lever III wrote: > > > > On Jul 5, 2024, at 1:18 AM, Christoph Hellwig wrote: > > > > On Thu, Jul 04, 2024 at 02:31:46PM -0400, Mike Snitzer wrote: > >> Some new layout misses the entire point of having localio work for > >> NFSv3 and NFSv4. NFSv3 is very ubiquitous. > > > > I'm getting tird of bringing up this "oh NFSv3" again and again without > > any explanation of why that matters for communication insides the > > same Linux kernel instance with a kernel that obviously requires > > patching. Why is running an obsolete protocol inside the same OS > > instance required. Maybe it is, but if so it needs a very good > > explanation. > > I agree: I think the requirement for NFSv3 in this situation > needs a clear justification. Both peers are recent vintage > Linux kernels; both peers can use NFSv4.x, there's no > explicit need for backwards compatibility in the use cases > that have been provided so far. > > Generally I do agree with Neil's "why not NFSv3, we still > support it" argument. But with NFSv4, you get better locking > semantics, delegation, pNFS (possibly), and proper protocol > extensibility. There are really strong reasons to restrict > this facility to NFSv4. NFSv3 is needed because NFSv3 is used to initiate IO to NFSv3 knfsd on the same host.