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 X-Spam-Level: X-Spam-Status: No, score=-5.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3A6F7C47082 for ; Tue, 8 Jun 2021 16:43:07 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 023CE6127A for ; Tue, 8 Jun 2021 16:43:06 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 023CE6127A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References: Message-ID:Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=wLms8daZbCf6sI5UTfIJnTRWZc42Gey1nV72lL9mgxA=; b=rJuMBo6mfBk2Ml dnUP+I/bTLfWpsYtqzVnGEdZhYc7P9wJCAZpKDxW2lNr6i9HUthaLovv4l0B8dpPwp8iuXqWoFQNJ b0XNXlfg++HVMqZgdVdV6GH6DDaRALPc7phbSbS9XWmmLUrj/hHGMownp3DX2klPyKGNfmp9QTmCc qqmQHXXeNmYDIz8tnvv7ViF6MwcEAb/zG1Ie+/JL3PkZRaDZPrTfXXi2SMRoK+saJa18gpB4s9Q2d KX/uxHhA33wltioRJGo8tq9A45/qULTmBeAmLe/AVDcTwWYGxpIHCAvavPHdy2Kw9susK58AaSbI5 gFxqXu6T5npLbYzOazpw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqeoX-009Z9H-C3; Tue, 08 Jun 2021 16:42:53 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lqeoU-009Z85-Hz for linux-nvme@lists.infradead.org; Tue, 08 Jun 2021 16:42:51 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 1C3BD67373; Tue, 8 Jun 2021 18:42:48 +0200 (CEST) Date: Tue, 8 Jun 2021 18:42:47 +0200 From: Christoph Hellwig To: Hannes Reinecke Cc: Christoph Hellwig , Sagi Grimberg , Keith Busch , linux-nvme@lists.infradead.org Subject: Re: [PATCHv5] nvme: allow to re-attach namespaces after all paths are down Message-ID: <20210608164247.GA12430@lst.de> References: <20210607133435.138525-1-hare@suse.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210607133435.138525-1-hare@suse.de> 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-20210608_094250_775519_8335A246 X-CRM114-Status: GOOD ( 14.38 ) 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: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org While I do like the look, I don't see how this could actually work: > } else { > ret = -EINVAL; > - if (!is_shared || !head->shared) { > + /* > + * If multipath is enabled we might hit an ns head with no > + * paths, but that doesn't indicate it's a shared namespace. > + */ > + if (!list_empty(&head->list) && (!is_shared || !head->shared)) { > dev_err(ctrl->device, > "Duplicate unshared namespace %d\n", nsid); > goto out_put_ns_head; When we get here with an existing ns_head with no namespaces attached to it, we can assume it once had namespaces attached to it. Because of that NVME_NSHEAD_DISK_LIVE will be set, and we'll never add the disk for it again. Even if we did add the disk again what prevents adding a disk and removing one from racing with each other? _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme