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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id C96ECC433FE for ; Mon, 17 Oct 2022 19:31:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3FE0A6B0072; Mon, 17 Oct 2022 15:31:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 386986B0075; Mon, 17 Oct 2022 15:31:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2000B6B0078; Mon, 17 Oct 2022 15:31:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id 0D6286B0072 for ; Mon, 17 Oct 2022 15:31:47 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id A0DE5140DC3 for ; Mon, 17 Oct 2022 19:31:46 +0000 (UTC) X-FDA: 80031436212.30.7B73888 Received: from NAM02-BN1-obe.outbound.protection.outlook.com (mail-bn1nam07on2067.outbound.protection.outlook.com [40.107.212.67]) by imf11.hostedemail.com (Postfix) with ESMTP id 018D440031 for ; Mon, 17 Oct 2022 19:31:45 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Vhzg3Q+LbzlPDKnry8al4eGFJ6o3Qx+mp0qHlKjbfNUkkY8zqE3W5hPJoZEBhooPMSpu16JROaucIShgdOLcf1QytJa/DHSeUJTY1L/ZVw1D8hpG4zIfbZfp1NOwQfkSRoBFEsN6ZX1N6BF3bDCaDWzSkReTqD3V/JKN5eHQ5WxNwLBNgOOlP9fPfSdJH8fw2XrkaVESUIWyL7Gnsu7faF9B7uTDFl4LbhHloifpOYzMJ5nxplZEOnfEwqk+/TwLvN1Md5DE0OLzVMZ68JvTUpmCI7xFYHfIx8echLYksg01CL+zUKRpilhbAqLDQTk0hY0VocN7L/4Ijh0fhQrWIQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=j1R4SEcX/NTGM+iEH3JVhYm4vd3kW9CTmvMj0YkYRPU=; b=fIINjK7SYHcn1x1ZIqVwyy9AD5MGYHM6JzrdN5a1WkcqPr1AwzVY/f0kCltLiQ8W9KmHR/3TvxMY9+EYAg0QvY5bzjcNesMXTGBkudPY0DgQf5wHKHvWH9827qkn0XlXebpJ0HtzGHDIGIpcECfbn3wIgWu/XTt/FY9yQS0Fdal7anySEC5wt03tBf9Fawx01AMH2fq4QCABXLfWtfG2tX+sqovC2+SIWmdHmCXGRHOQKe8bbb1Xg8xbc3BQIFVesAlQDLydffWzCVNY0vDYgq9lJiaCF/nbfuwYg9ZcHtMGx2gVH3H0zn92A2QgX2dN+TrOToxwdTqSFdOuYVpS0g== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=j1R4SEcX/NTGM+iEH3JVhYm4vd3kW9CTmvMj0YkYRPU=; b=dpFv+/F1pGK8fn9YFMayIrg4hf7wb3qH9Cl5e6PAGZy4Ia7OayLFTWG3RQeFnJjG8FquPd0veZlIWPKUSmmfojJygVqnK1szSmY1Dl3vg6XNps7lO2lRfwmKapfE0T8do1dunJE/678k1WqTIRzRdBSci7BdZ9Luao+zNqXL8ewXzxGd4ZukWOZEm6LhbPpI4gu8Jt+QuEthWH6DjdTH6fdq+QRQoeFav6tF6kIYsYwxhQ7THrgx72dmKcblA4liGVmBO4yFGTGL1dgYUzTTnWO9Oihg6a27WrIrP9PpILUd4EiUsPAFzyYfr0UPR/Lgc8IXp6YNlgLdqlGwZARNEg== Received: from LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) by PH8PR12MB7232.namprd12.prod.outlook.com (2603:10b6:510:224::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.5723.31; Mon, 17 Oct 2022 19:31:43 +0000 Received: from LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::7a81:a4e4:bb9c:d1de]) by LV2PR12MB5869.namprd12.prod.outlook.com ([fe80::7a81:a4e4:bb9c:d1de%6]) with mapi id 15.20.5723.033; Mon, 17 Oct 2022 19:31:43 +0000 Date: Mon, 17 Oct 2022 16:31:42 -0300 From: Jason Gunthorpe To: Dan Williams Cc: linux-mm@kvack.org, Matthew Wilcox , Jan Kara , "Darrick J. Wong" , Christoph Hellwig , John Hubbard , david@fromorbit.com, nvdimm@lists.linux.dev, akpm@linux-foundation.org, linux-fsdevel@vger.kernel.org Subject: Re: [PATCH v3 07/25] fsdax: Hold dax lock over mapping insertion Message-ID: References: <166579181584.2236710.17813547487183983273.stgit@dwillia2-xfh.jf.intel.com> <166579185727.2236710.8711235794537270051.stgit@dwillia2-xfh.jf.intel.com> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <166579185727.2236710.8711235794537270051.stgit@dwillia2-xfh.jf.intel.com> X-ClientProxiedBy: BL1PR13CA0363.namprd13.prod.outlook.com (2603:10b6:208:2c0::8) To LV2PR12MB5869.namprd12.prod.outlook.com (2603:10b6:408:176::16) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: LV2PR12MB5869:EE_|PH8PR12MB7232:EE_ X-MS-Office365-Filtering-Correlation-Id: d11e3262-aa7f-42bc-040a-08dab0763909 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:LV2PR12MB5869.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230022)(4636009)(396003)(366004)(39860400002)(346002)(136003)(376002)(451199015)(36756003)(86362001)(2906002)(4744005)(8936002)(7416002)(5660300002)(66946007)(66476007)(41300700001)(66556008)(4326008)(8676002)(316002)(83380400001)(6486002)(54906003)(186003)(6916009)(38100700002)(2616005)(6512007)(6506007)(26005)(478600001)(67856001);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?lniN+3uN/3adCGu/YK+943lsSpy4U65eIxHMdEuA5KXR1zzTJ+FdLoQK2tC1?= =?us-ascii?Q?d7PitV2skuYNoJWU34eLTK4opeaEOKZEJfs6+WSALxDb2sYVUeMKNLefEKlH?= =?us-ascii?Q?7NML18wv9ecmyoIzsIB7eOckEjmJOA2iGtU9SHGBRBEf9zDqXtx4jJd3I/aJ?= =?us-ascii?Q?ZfcNBmzpHtz3ux/8wNAtWkT4RDFTYDV5zxIQ8KRWYFGZc4UYEY0qPloB4vQA?= =?us-ascii?Q?YfmgmY9FZm7imqkSG5pDrzOomqx4zS07XHCU52OtvzoTFwLYU2Pm7O7EFuNA?= =?us-ascii?Q?rMWDFehOochJeB/0jyswrWG5M+MPNXv4+oBSf28fkFOb3351pWUl4k/OZ98o?= =?us-ascii?Q?QRocWCg1kfN1dReKpcWt3wB5W+i3h3YImjK4asUFtPKMYtv5Tvys5nE+R3iR?= =?us-ascii?Q?hPcD3c2IamsmERza4FfqVccP5wGFk0KjbI7H5FZUErR2fcsuo/KpuqsWWu+k?= =?us-ascii?Q?z6exM8A/BgWDvNy1E41IbOkS+yk/XDcj7kJa1XSZgJv6g+f+tjHUxKXAFXMi?= =?us-ascii?Q?IIbGGeiNwLHX99tT7MMoxxx9jN8OYcnfBgq08qmejwAFR7BBFH01UyqQQz/A?= =?us-ascii?Q?JFxCMN2yCKJSbfOsxbXOtWratNe5QKQoR/3QvhtxBOdPSs4AthKDkFkknYsy?= =?us-ascii?Q?Yco8EL/DeFz51jgtAB039dnKrkfQ9QHpN+YOwd0smwtFBcGSXNC7n2CB7aU1?= =?us-ascii?Q?SWpPxUIdYsmJdLADmN6LnSyyIqt/YZjx6gOCb280KT4p9z4KghTW+v56iydr?= =?us-ascii?Q?eU23Jn4rqsDa5ZcDmkI/YEBpFKbBypyZYSIRatMQSKVhulIEGhYz3uTdreFO?= =?us-ascii?Q?vZrf2DvJ7MVyUdNgkpSfuaQZElwGW1O0DLkJvdCkM0MFwQoOl6L6ZJjmz1MY?= =?us-ascii?Q?EnFpi7g/72qxIpGew/Gu4E6/w3XZxESEQqBYiT3i5uoVClKrdwp/UGkdsWei?= =?us-ascii?Q?VhvVOL66rK63YnY8+UR/EUL9ElyOTLR9In7BXcHfK9LQv41YzGZT2zO354E7?= =?us-ascii?Q?Q0pnMlRs70e7grjJq03k/gUGVn8PWcU8tlPHH5xeBgdlv4FYySynZ8zoMYiG?= =?us-ascii?Q?WYrp3rek/3pW3i/hPVmS6BBonyFntPeolmNR/8+8OTvAe0VCecxCPe85Wh3P?= =?us-ascii?Q?vHVcxfZxgcmIHqyAM9RZjU9dCD3T5gOcVdPxL78q6qcyQRfB+0AyBs4tQ9aE?= =?us-ascii?Q?AE2Nt2Cdn/6akurQoUH10KCQwADYo5qxTdkvM++zWUx/5OE5kftY0xfHs1Y1?= =?us-ascii?Q?aleNU+bqQNVHzCrwprcFK44H3wHggnAAYDyz8SzYWIEtSrX2OAihUNcnI0BA?= =?us-ascii?Q?ZZxSD4HxaRRMr7NE99nCmxTeqJa1O0e00hFQDWagsTG8SwgSGmOhM2LEnFmQ?= =?us-ascii?Q?Cbf2w9QahvBn/soRGHQkwFmY6wR+wzg3xeLolKsUBS6BacyWvlLojFlQXKHQ?= =?us-ascii?Q?vrj78XVFQo6GGs9Odeyea8hC4KTFkpHCkeREkmRikDuuE/3/rjQWvznPJxZG?= =?us-ascii?Q?E/mbTC1xL75BLmo3NN5GLRsfK7Y23BzCuyOdwwUIoqjiSvezZz6vgXU31NXr?= =?us-ascii?Q?wq4JBDIOOKcx3tUiwew=3D?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: d11e3262-aa7f-42bc-040a-08dab0763909 X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Oct 2022 19:31:43.7274 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Ko+LWsCOO8qr4GSmWkoT0KHPljm9jQDn8/vBOXw93JSpcTXbkyHAHicQl5owwGSJ X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH8PR12MB7232 ARC-Seal: i=2; s=arc-20220608; d=hostedemail.com; t=1666035106; a=rsa-sha256; cv=pass; b=N8KbB939Ftap0lDgr+VkptyRN1bFP4sByTnFSgV+L2UCDZHhAHENP8rTvJ/Ed41Uvb1ZD7 nfu6LFjjFvl1qo1St2wBwmqxaZhBvX34zywc8ZDW9SecMFQ5HepuXNIq9SkTIM1kBmvWzy 5qdRyH0IH0PX0hn3pedDZPsjp3inoS4= ARC-Authentication-Results: i=2; imf11.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="dpFv+/F1"; spf=pass (imf11.hostedemail.com: domain of jgg@nvidia.com designates 40.107.212.67 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") ARC-Message-Signature: i=2; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1666035106; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=j1R4SEcX/NTGM+iEH3JVhYm4vd3kW9CTmvMj0YkYRPU=; b=ZOTh8lF0YkZbqjMEedUb4tCGnCP2nQHGP2i/yzmvhWAe4j8+olcBRLMw1UsBniqCOYfCAn 4Tw6VK9AM0efqSrIMuC7sbBwjCW7KluVl/dpzSlZ8nk+14TJWW+mcJafn/bL0pIRYo5qhz vZhk+dkOcwM6tuiNoBOooQ41a07OWrI= X-Stat-Signature: 6riqrbbnabg4pemsqswbo6nzbxqtjw4y X-Rspamd-Queue-Id: 018D440031 X-Rspam-User: X-Rspamd-Server: rspam03 Authentication-Results: imf11.hostedemail.com; dkim=pass header.d=Nvidia.com header.s=selector2 header.b="dpFv+/F1"; spf=pass (imf11.hostedemail.com: domain of jgg@nvidia.com designates 40.107.212.67 as permitted sender) smtp.mailfrom=jgg@nvidia.com; dmarc=pass (policy=reject) header.from=nvidia.com; arc=pass ("microsoft.com:s=arcselector9901:i=1") X-HE-Tag: 1666035105-318464 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, Oct 14, 2022 at 04:57:37PM -0700, Dan Williams wrote: > In preparation for dax_insert_entry() to start taking page and pgmap > references ensure that page->pgmap is valid by holding the > dax_read_lock() over both dax_direct_access() and dax_insert_entry(). > > I.e. the code that wants to elevate the reference count of a pgmap page > from 0 -> 1 must ensure that the pgmap is not exiting and will not start > exiting until the proper references have been taken. I'm surprised we can have a vmfault while the pgmap is exiting? Shouldn't the FS have torn down all the inodes before it starts killing the pgmap? And since tearing down all the inodes now ensures all the pages have 0 reference, why do we need to do anything with the pgmap? Jason