From patchwork Wed Aug 7 22:18:15 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Verma, Vishal L" X-Patchwork-Id: 11082759 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 071A31398 for ; Wed, 7 Aug 2019 22:18:22 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EB3DC202A5 for ; Wed, 7 Aug 2019 22:18:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DB0ED286E6; Wed, 7 Aug 2019 22:18:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 7D67A202A5 for ; Wed, 7 Aug 2019 22:18:21 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id 73F392131D56F; Wed, 7 Aug 2019 15:20:51 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: Pass (sender SPF authorized) identity=mailfrom; client-ip=134.134.136.126; helo=mga18.intel.com; envelope-from=vishal.l.verma@intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga18.intel.com (mga18.intel.com [134.134.136.126]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 8C6712131D565 for ; Wed, 7 Aug 2019 15:20:50 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Aug 2019 15:18:19 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,358,1559545200"; d="scan'208";a="203354362" Received: from vverma7-desk1.lm.intel.com ([10.232.112.185]) by fmsmga002.fm.intel.com with ESMTP; 07 Aug 2019 15:18:19 -0700 From: Vishal Verma To: Subject: [ndctl PATCH] Documentation/namespace-description: Clarify label-less restrictions Date: Wed, 7 Aug 2019 16:18:15 -0600 Message-Id: <20190807221815.25782-1-vishal.l.verma@intel.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP In the ndctl-create-namespace (and related) man pages, add a clarification note regarding some of the restrictions a user may see when operating on label-less namespaces. Link: https://github.com/pmem/ndctl/issues/52 Reported-by: Jane Chu Cc: Dan Williams Signed-off-by: Vishal Verma --- Documentation/ndctl/namespace-description.txt | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/Documentation/ndctl/namespace-description.txt b/Documentation/ndctl/namespace-description.txt index 94999e5..5f294be 100644 --- a/Documentation/ndctl/namespace-description.txt +++ b/Documentation/ndctl/namespace-description.txt @@ -18,6 +18,12 @@ the kernel's 'memmap=ss!nn' command line option (see the nvdimm wiki on kernel.org), or NVDIMMs without a valid 'namespace index' in their label area. +NOTE: Label-less namespaces lack many of the features of their label-rich +cousins. For example, their size cannot be modified, or they cannot be +'destroyed' (only disabled). The only operation supported on them is to +change their 'mode', by adding on-media metadata which is then used to +identify an address abstraction mechanism for the namespace. + A namespace can be provisioned to operate in one of 4 modes, 'fsdax', 'devdax', 'sector', and 'raw'. Here are the expected usage models for these modes: