From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id F27AFEB64D9 for ; Mon, 10 Jul 2023 07:01:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5acEXpJaJrxecyVx0dfv2F5VnAmsfMn8VBXyUUXclG4=; b=ZYe6SgD+XNwKJAo9U9zpAa/1Od 1MJgJ97HshGYbAtcWMpBQD4fXg9ZD+lY+Zo6/VQw7CPiEuPMRIRBD7DkLRcEpP723bgy9dNUh/HzF fneqgAUI4FryidxQ8MJ22FVyVEWdw8I+ticGt6mbVEBwUVF8++iyVcnnb21C72itWk8ElEmETuONP 9zbnSQcXfCEwChX7wTyRTFSzR/KgvoNDvHOBAlFH+Og4zw9ViXullZTaq/+xEEudKdnIgUzAv42lz 80YojMDkS82V6o8Bvi+UnK9szTzbXZXRd+SW6nGmFN7pg5In6kkuiPCFVC/I3mn2elKm9U4dFuYSh K5jSQAAQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1qIkta-00AeSU-0F; Mon, 10 Jul 2023 07:01:18 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.96 #2 (Red Hat Linux)) id 1qIktX-00AeR5-2M for linux-nvme@lists.infradead.org; Mon, 10 Jul 2023 07:01:17 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 46B7567373; Mon, 10 Jul 2023 09:01:11 +0200 (CEST) Date: Mon, 10 Jul 2023 09:01:10 +0200 From: Christoph Hellwig To: irvin cote Cc: Max Gurtovoy , hch@lst.de, kbusch@kernel.org, axboe@kernel.dk, sagi@grimberg.me, linux-nvme@lists.infradead.org Subject: Re: [PATCH] nvme-core: check id->mc before setting NVME_NS_METADATA_SUPPORTED Message-ID: <20230710070110.GA26047@lst.de> References: <20230624103502.8772-1-irvincoteg@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230710_000115_912313_CD7AE7EB X-CRM114-Status: GOOD ( 15.15 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Jun 30, 2023 at 07:41:27PM +0200, irvin cote wrote: > >The MC field is primarily for use when sending a format command to know > >what are valid possibilities. If the reported MS and FLBAS are out of > >sync with metadata capabilities, then the controller is broken. > > Beware having MC and FLBAS out of sync does not necessarily mean we > have a broken controller : > MC could be 0 (no metadata support at all) and FLBAS has no way to > express that, it can only indicate which metadata type was selected by > the user. > In such a case we could wrongfully signal metadata as supported when it is not The LBA Format Data Structure indicates the metadata size for any given format.