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 C319622332E for ; Tue, 8 Jul 2025 15:19:34 +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=1751987974; cv=none; b=KPtSPly0JC2uEd+o/C4k73aL/yOB5zg8tPWuBXBCN+p75pRDk8GaJ+Xtl4WiJ3ne4s7ky7bW04sBDSaZz3EKpIOhP53B+H499llczJiqBU+Vftz7XaDQPwZD5M5E7sEG0q8UEAVo/c+Go5K+rwROUXN+9WpCTQU/CQFWiMfl+e4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751987974; c=relaxed/simple; bh=8DQsrgvQi7kSBbdxmjyQivePr825j0lx1nkfT/q8/a4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=cB62swF5Exddpm6O5FjFdmGHOtLgx85uKJjWxBRj7CKxZQGzESNs8Y5QcyBpjY/gbklhFFGb3Q9RksG8JALwr56lmEVbWz7UR2ZYDeRXDDRkpJFK2b2FRkI/+IDK0vh5+Qt9qih1bFyV0F4W/tbrAv+9TxXQ+Ooe5+CAPeZHZLc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=f9CnsbrP; 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="f9CnsbrP" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2E232C4CEED; Tue, 8 Jul 2025 15:19:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751987974; bh=8DQsrgvQi7kSBbdxmjyQivePr825j0lx1nkfT/q8/a4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f9CnsbrPXZqNEd7AFivWGneCYJczJJ3d484wQkrWGdji8N4Mr8v3pB7dIMLgBIpGK yDh7QtVsY2VwqESKRjjNShxxVXZFThupqg1xPCGcpT4MZ6zUKh4NhyjHvFer+oBqVY fjGkBqTxONx340cZz6/mYwOeWtTzugzBNdLzKckAxZ9dlqhKgZukSeOBETFrX1xXHX mhAIaadtdxKIlEcFKGH8kbxb736KrwjrzZ4pcKJV/JmWy3tSzoUXxfAgcSVhGM8h5f wj0QFPS/JwSHsuinoKZXFBO5fY6nZ3hE9jzJcPXGnuI4hc7StPEGvIZRSx2ISjQqiR 9TeZRlZyhImEA== Date: Tue, 8 Jul 2025 09:19:32 -0600 From: Keith Busch To: Christoph Hellwig Cc: Hannes Reinecke , Alan Adamson , John Garry , "Martin K. Petersen" , Jens Axboe , linux-nvme@lists.infradead.org, linux-block@vger.kernel.org Subject: Re: What should we do about the nvme atomics mess? Message-ID: References: <20250707141834.GA30198@lst.de> <20250708094748.GB27634@lst.de> Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250708094748.GB27634@lst.de> On Tue, Jul 08, 2025 at 11:47:48AM +0200, Christoph Hellwig wrote: > On Mon, Jul 07, 2025 at 09:56:53AM -0600, Keith Busch wrote: > > Just to throw AWUPF a lifeline for legecy devices, we could potentially > > make sense of the value if Identify Controller says: > > > > 1. CMIC == 0; and > > 2. OACS.NMS == 0; and > > What is NMS meant to say? namespace management support? Right, namespace management support. The spec calls this field 'NMS' now. > > 3. > > a. FNA.FNS == 1; or > > b. NN == 1 > > > > And if those conditions are true, then the controller and namespace > > scopes resolve to a single namespace format, so the values should be one > > in the same. The only way it could change, then, is a format command, > > which means there couldn't be an in-use filesystem depending on it not > > changing. > > We could. But are there many controllers where that would be the > case and where people want to use atomics? Maybe not. I still have a lot of 1.0 compliant devices where this might apply, but I don't have a use case explicitly needing the atomic write features anyway, so it doesn't matter to me if the driver doesn't report the limits for them. So I guess no need to work with such devices at this point, but maybe just something to consider in the unlikely event someone complains.