From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.17]) (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 B2FD07FD; Thu, 9 Jan 2025 00:14:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=198.175.65.17 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736381672; cv=fail; b=mHjUPvOJnbKFX3BL/PQbZFIAMhRoEg5ILJhLkTPQt3dh4pjKinm3uJASZSW/+4vlJSKJo+cH+6JPKypNkuOPR0fSMe7oqRGSnmLddmeCOu1wPostwwoKrBC2/vIAqb5/37PpeXdWpd6/Zep04X+bgbSlg439ZbiP2eJTX76xrNE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1736381672; c=relaxed/simple; bh=RNhUvrYzureu1Wcz6QVzpvRxfytm2tn7PdmcHQnmL+o=; h=Date:From:To:CC:Subject:Message-ID:References:Content-Type: Content-Disposition:In-Reply-To:MIME-Version; b=e+1U9Wt4fjC0EzpCD1WVWJoE330bcc5+vCSVNIrrHbS2dZcsMnuZ6XhfzXlp1wsRjWMPhBtiFpXXjBuJrwVVTM9ysqfD4VlfWIQmxa+EVD0zHrzVqHi4wdC8hUCINxUJ1Bk9pzYtb04FggjSWZ0hHP4Us7eyYRqN4OEeLRHcTg8= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=PTm7lv+u; arc=fail smtp.client-ip=198.175.65.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="PTm7lv+u" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1736381670; x=1767917670; h=date:from:to:cc:subject:message-id:references: in-reply-to:mime-version; bh=RNhUvrYzureu1Wcz6QVzpvRxfytm2tn7PdmcHQnmL+o=; b=PTm7lv+u3cHWbGIsrhawSYI+zuEOCs9+Yywo+RZOnKrfzO5Xvf+qozVL fzG3c0vK08v6gpkrQ7PUQlpLZeIVE/1kJghDiniRNV6n2Re64Shbbknlt 9ThaW7V8+IpPoRUU2d5IlNSdDDga7iq69lykA9846CuE2QcWlUaMTZR/v noJ3RQBlSRmK4uWorq8E0Imm2G5UYhSQxtgAaYVQBdSvq6svw282ffRlb lJ9WhsNUZXMzCCbLBYRETPmNdYRWMnrNx0wAmNj987AkdTYqai3qd0RVT vZGOzTgDRvTF8hSHyBN3TIOsljyMqjeSAgBJdD/fma/GRwNf4F/FManB/ g==; X-CSE-ConnectionGUID: KLxlUZBkT9eHAaS7RGJmcA== X-CSE-MsgGUID: hOFL5UbMQ/KAtUesRZwJPA== X-IronPort-AV: E=McAfee;i="6700,10204,11309"; a="36646647" X-IronPort-AV: E=Sophos;i="6.12,299,1728975600"; d="scan'208";a="36646647" Received: from fmviesa003.fm.intel.com ([10.60.135.143]) by orvoesa109.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Jan 2025 16:14:30 -0800 X-CSE-ConnectionGUID: nv7xC/6gTwWlcpkvaHqRMA== X-CSE-MsgGUID: p4r2fVD4QNCe+brL6wRJ8g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.12,224,1728975600"; d="scan'208";a="107292053" Received: from orsmsx603.amr.corp.intel.com ([10.22.229.16]) by fmviesa003.fm.intel.com with ESMTP/TLS/AES256-GCM-SHA384; 08 Jan 2025 16:14:28 -0800 Received: from orsmsx601.amr.corp.intel.com (10.22.229.14) by ORSMSX603.amr.corp.intel.com (10.22.229.16) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.44; Wed, 8 Jan 2025 16:14:27 -0800 Received: from ORSEDG601.ED.cps.intel.com (10.7.248.6) by orsmsx601.amr.corp.intel.com (10.22.229.14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.44 via Frontend Transport; Wed, 8 Jan 2025 16:14:27 -0800 Received: from NAM10-BN7-obe.outbound.protection.outlook.com (104.47.70.42) by edgegateway.intel.com (134.134.137.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.44; Wed, 8 Jan 2025 16:14:27 -0800 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=GmOZfc4JdjhCtvRz0kEDFD2H4sMtgFPoNMUlvgfdERDHQU1uuov4NpiJAmlTWbgdC+w+HnEB9LAQP1fOfA8K9tO54cchdI/gCrwnjIeZsF3YbB7dU9RgXWrueUHfbzZqXPwSCHKL/4gCNbU8IJZjRCI0qAi9N4sE+dit4YV0XHekQy5QgxSmRXKoZxgaHDgBjh+ycs+kQBep4ikB9R8pkjl/wDHavewC2lxxt6IOz4yS3rFxhglYomIYWWl0aLstDyGtMD7blTQNZ3bGF4sd6cqbP27/AVLHGX5eexCaCcBYDVRiv4BVRd3fO4DYf/I1NsfFg/i3PHnA7nITX4k9cg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; 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=03LWZx/Dcm2M7hIFkswGHb3oGb9DtsrgN0DKrTJeKac=; b=Y4DcpiyCKXcZFvMzOYE2YFepMNXaoK2AxKnf+Jqekep9bGSqMlO8QderzwPO0DQpodRjwTou9QO++mdjmIyE/xwnG/CFJgs3yoCUeF87p2PL/8wIueog16gJNWYejhspLIfulBRL0Jj0nY30OuvsqovppkvOBDSLEYzWb5RBQ+37NV8M28Yn+dFAUWoW3veC5L5WpVP9EYu8CYOFfosJG01/RbeQnozMYgtKv1zhcm4Sjw5rbY3ZxJCsI8T4kp7rZfBQTlGpu+KQbbgQE+86mgrv5vPEM1SKzchwPd/BTvhRqdt9jsXlrZDD1tXBKifu7b6Rp1EWTukFXQodxY4Xdw== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=intel.com; dmarc=pass action=none header.from=intel.com; dkim=pass header.d=intel.com; arc=none Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=intel.com; Received: from PH8PR11MB8107.namprd11.prod.outlook.com (2603:10b6:510:256::6) by MW4PR11MB5910.namprd11.prod.outlook.com (2603:10b6:303:189::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8335.10; Thu, 9 Jan 2025 00:14:24 +0000 Received: from PH8PR11MB8107.namprd11.prod.outlook.com ([fe80::6b05:74cf:a304:ecd8]) by PH8PR11MB8107.namprd11.prod.outlook.com ([fe80::6b05:74cf:a304:ecd8%4]) with mapi id 15.20.8314.015; Thu, 9 Jan 2025 00:14:24 +0000 Date: Wed, 8 Jan 2025 16:14:20 -0800 From: Dan Williams To: Alistair Popple , , , CC: Alistair Popple , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH v5 05/25] fs/dax: Create a common implementation to break DAX layouts Message-ID: <677f14dc3e96c_f58f294f6@dwillia2-xfh.jf.intel.com.notmuch> References: Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: X-ClientProxiedBy: MW3PR05CA0017.namprd05.prod.outlook.com (2603:10b6:303:2b::22) To PH8PR11MB8107.namprd11.prod.outlook.com (2603:10b6:510:256::6) Precedence: bulk X-Mailing-List: linux-ext4@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: PH8PR11MB8107:EE_|MW4PR11MB5910:EE_ X-MS-Office365-Filtering-Correlation-Id: 69f2d7b9-6dfa-4f45-4eed-08dd304292d7 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|1800799024|366016|7053199007; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?YbrRzBodjh9IUP4TfL5QAzhpBu4j5pffZHY5j807wpdpvDmbntu1jmUBHT76?= =?us-ascii?Q?uUmVO/pP2ftH8v+UN43dwOxXf+2/huuqIbQjgpvBBAY3wOJDa98XZzbgOERl?= =?us-ascii?Q?yjNm0Kl2pdJeXa7w95rbazz2ez5ot2dDPaTdl4X/PMSFQCpNaem5ni6VjzsU?= =?us-ascii?Q?0eJlOJxgWU+ElhskZ8I5b0fyGJIfHj4mULM536cpj6UsSkbSpzWMIvJ9mpQb?= =?us-ascii?Q?7KUI6TfQkK8kmya13h4uFPawth5uQ6g2YjCM9FujPFLO6zT61AmlwLM3Uhlp?= =?us-ascii?Q?lMFXwTV4mnz2ycKYPGVP/NsSfgz+BpHWu8UERjLPcl/m/WrNTkuD3nOhKQyu?= =?us-ascii?Q?LAzF92xR1VMscdGhSNgKf3vDXiiqAL6m2maWD+JQ/1/rBe2URmX2tZjx8ee/?= =?us-ascii?Q?mJaKdpg17VKdy0xrG0iYnr59IwpuXti5x+jzcP0Mtv0Y9//X6vq6mKBymYGo?= =?us-ascii?Q?1SPY38+r7uWAmRshMJDihXkWXbopJ/dOyUumLzn7fD0oPDWD65xqjhwpDfzk?= =?us-ascii?Q?c0KiBjE6PPfDNCwuz4sI0iOqh6xmldLkO28iAdH/wpMA2kGUtoY9ZrEzchgY?= =?us-ascii?Q?UYBwCTuT/xyEGFyX4W2Reyrj6d6rSks7jH1QG7vBBg7/vVgnwxU1jP04jKtr?= =?us-ascii?Q?mEF3jK3yDjDOlnK2Ujnj/qBwfqcMCAX2wtfH8zWZ6HjoMT3CtObWRVdCZPS1?= =?us-ascii?Q?n3mLvvfgusRwwgheoRBCdC3nB2FLS9iI4l05Jp4XVlipjAoVWyWuxSvgLQZa?= =?us-ascii?Q?pm9Rt1uMRhqxkYHXi7WI2Y/JZX0iem6f5VesVRP/7HmibksjFltPxmnzibpo?= =?us-ascii?Q?24fGGotCcQHO93yc/MmBvZ2H1oF+sDbKNRbfNOXSJsuYmdWhldtgmI/Dg08H?= =?us-ascii?Q?dZqkOCyP4C4r8FEN/pXz3UhEfJFHGb3tLVmKBAmLRPh5jnfse8ZSfZVYZMSs?= =?us-ascii?Q?fL8NpQVrRMeYPGv0+Qxw6vb3rrLj9VV+sr8hcOsR3WhitzKBKHKZ/ulh4l/v?= =?us-ascii?Q?Y1M5mXkzwcAhpo+I6kDfHkbEV4ZGODff9gCtC6Ryug3RBTnDs8dNY8yChIZH?= =?us-ascii?Q?+mUxXUDIqKd/Gu/9PFOCfRUnGYMaZEEMntRXXLVBxdWIFcb+zlp+eTDTT35b?= =?us-ascii?Q?fWhNxlmyf/tUwsFK5c9AVYy8KBopW2rbs+BuuyDeiR4MQUV1jILfUBngtAKn?= =?us-ascii?Q?Lmzg3LkfqBAH7b3TTdj2qapeCmbNYbTcUb83tdFtdvv+/SNmAHcfG4hDzeHq?= =?us-ascii?Q?ZjCtKzQNZGXZWDc8iPFY1pWnUkI8A207amm+UbwJ+3Vu0QuY7n+oz7Ukt0U9?= =?us-ascii?Q?I2286Cn6Mfo9rHeqiAYcaoDpn9s2iFAwcxPyOS2IvgGCvrIH5nrV2r/wKlFw?= =?us-ascii?Q?WH7QEH1lpnpun1SAbOB0LNFLEUBO?= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:PH8PR11MB8107.namprd11.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(376014)(7416014)(1800799024)(366016)(7053199007);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?UYOPjVrmzv1r+jnp1PDAyseNFFmdL2iat+rIQ/BalkiqqozhuvtV9cUcu9Sz?= =?us-ascii?Q?rn5B0puQRMD/cXlrNwFas7CdLKr17i25Z6o1SjiUhgUaQu8dGvP8Zta6QGQc?= =?us-ascii?Q?k9nQxvPX1oR9GN/A7F/M78WfUqKX8GHzaexXTEr57HbgMnN9xZz56gzkAma3?= =?us-ascii?Q?2t0PgQ8XF93J8kC6Vi46IfmenqUDO5wFgy63zmXBshHqmSEhqKITsqGbl6Zv?= =?us-ascii?Q?i0r852i3XXDYPXT8VR4SvvJoMQTM9zuQj9A27aTKmbEgcQ8OEIutSiNtSC7q?= =?us-ascii?Q?MdDEuTrDyGypcTcRRgY7evJjXu/3ZW0f5e0DdlYUMl/0Pnl12g5y9aQj3Jwe?= =?us-ascii?Q?QRTTwaqsf+y+s27QHblVYhGVx7mxvHNG7jK1VeVdkB3prkwyPunfJjT5gM3c?= =?us-ascii?Q?OjYY/pEX5NTQYlF15kbZOO6LRol0rtpxNFJJ+n+5aU5zjdR6CmmI0awjCEu7?= =?us-ascii?Q?2rpc63rzVy1+zIimGsPEk17nD7RfdBQVCV7RLpu5OTQuqGewEnAog4Nhxs+L?= =?us-ascii?Q?Nrni3R6W8D7mOSOKK7/SIwFfqNuhAmL8/+it0Dgsqi0Z2+SwgxTpCuByNIMt?= =?us-ascii?Q?iPaG4/xo38kQcl5CxDwkoBKhXSZlyu62GVBAwbhOihz4hmtymb+gLo2qZFVO?= =?us-ascii?Q?KeX0rr0kJhLgQHNLKy6wfFBR5hpzVnEneLnmKyxKlqDa4/p2B5sNGv9a3qL8?= =?us-ascii?Q?Dob3PY3rgQAaF76Ma4y6gZywgEGE/jwoH7nWjeAxolPa98IQMi72g8s7cKQ1?= =?us-ascii?Q?YugW48Jb3SOdL2Jft2g4pAt/aGhIRFmt6roriqgLNzIIuoXbDO6XV40ak34k?= =?us-ascii?Q?9KC//mZTDGjoF+cAqlE+Kd2QAsE7xn0+bS0ipSZ8TgVp+7u+P+tZW1EDrPiC?= =?us-ascii?Q?SKWajOBAEK8Ldd2vsIl07EOupF7/F59fSQmHH9X4bf5+MT0yKA1xT3FzBwty?= =?us-ascii?Q?8y//eQaWNOJrz44OaWBMtnQKVv/IVDMML11KjR0QQzcIk69nQ+uk7jOVMtlY?= =?us-ascii?Q?fVdLRxOHaoWKQ7UCDxML1SZOcwg4WcUVIcT9gHbqzUqjdLxb/R8lyPNhlIj1?= =?us-ascii?Q?8vvWLc5MrtiAC2ON80JOuCALs1Cb5XbdcHuAePv8xn9Sg3UxYNARFbWv7YJ0?= =?us-ascii?Q?1Zb0CCnvma4wKlggn90mroonWuHI9YIboEvkJcg8nuirkkNwcK5pNtWjKBSD?= =?us-ascii?Q?HZIoP34bUawjVU4Di5+8HXmaZ8nDX9tFJchBTyq7RLBL3S622BecSV8ODjMg?= =?us-ascii?Q?DyjCuaFeHtOyGLSBVYlTE+wAdzk/aJe+0Wco5Rr87UQQe8FvYnLBGKZ26Hze?= =?us-ascii?Q?cVmyGQS9eiaMKaP0+mFj3YsazQ2aPAIu+yUk9X3Fq3KDdkPXqjKBkDGO7vGk?= =?us-ascii?Q?IoLUrgwpmawmBGRWwFDd8Z9hW6LfoKeg8QDl+m5fCIHTr1jW0JsxAxgm9CYm?= =?us-ascii?Q?u4glx83os61X/TTWzOw2dfHb8H44CKqImqJfJ7Uz4SjlNNOOA7Wk4zLctiaW?= =?us-ascii?Q?MLya4PbWV5QucRGBeMlH+2rzJXmca6uvwa1JqQUZzIjfxgYUOiV6Uv5xIR/o?= =?us-ascii?Q?xSePUBomS8aCMxJ/BKVYEIJsbXHuRCbjEZbCeMfjThncIxuvsPkmO1bfsqxR?= =?us-ascii?Q?gA=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 69f2d7b9-6dfa-4f45-4eed-08dd304292d7 X-MS-Exchange-CrossTenant-AuthSource: PH8PR11MB8107.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 09 Jan 2025 00:14:24.7510 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: v5qSL2SlE9Yc4dQnMD5LVxmzx0AmSAgnRcnPu9+ADORw+M8elwJKf36EHOu+ulIJRRMqmUGB+7sRlowXCQBifpCfwwtSrO214/SZd3dDG7E= X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW4PR11MB5910 X-OriginatorOrg: intel.com Alistair Popple wrote: > Prior to freeing a block file systems supporting FS DAX must check > that the associated pages are both unmapped from user-space and not > undergoing DMA or other access from eg. get_user_pages(). This is > achieved by unmapping the file range and scanning the FS DAX > page-cache to see if any pages within the mapping have an elevated > refcount. > > This is done using two functions - dax_layout_busy_page_range() which > returns a page to wait for the refcount to become idle on. Rather than > open-code this introduce a common implementation to both unmap and > wait for the page to become idle. > > Signed-off-by: Alistair Popple > > --- > > Changes for v5: > > - Don't wait for idle pages on non-DAX mappings > > Changes for v4: > > - Fixed some build breakage due to missing symbol exports reported by > John Hubbard (thanks!). > --- > fs/dax.c | 33 +++++++++++++++++++++++++++++++++ > fs/ext4/inode.c | 10 +--------- > fs/fuse/dax.c | 29 +++++------------------------ > fs/xfs/xfs_inode.c | 23 +++++------------------ > fs/xfs/xfs_inode.h | 2 +- > include/linux/dax.h | 21 +++++++++++++++++++++ > mm/madvise.c | 8 ++++---- > 7 files changed, 70 insertions(+), 56 deletions(-) > > diff --git a/fs/dax.c b/fs/dax.c > index d010c10..9c3bd07 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -845,6 +845,39 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) > return ret; > } > > +static int wait_page_idle(struct page *page, > + void (cb)(struct inode *), > + struct inode *inode) > +{ > + return ___wait_var_event(page, page_ref_count(page) == 1, > + TASK_INTERRUPTIBLE, 0, 0, cb(inode)); > +} > + > +/* > + * Unmaps the inode and waits for any DMA to complete prior to deleting the > + * DAX mapping entries for the range. > + */ > +int dax_break_mapping(struct inode *inode, loff_t start, loff_t end, > + void (cb)(struct inode *)) > +{ > + struct page *page; > + int error; > + > + if (!dax_mapping(inode->i_mapping)) > + return 0; > + > + do { > + page = dax_layout_busy_page_range(inode->i_mapping, start, end); > + if (!page) > + break; > + > + error = wait_page_idle(page, cb, inode); This implementations removes logic around @retry found in the XFS and FUSE implementations, I think that is a mistake, and EXT4 has apparently been broken in this regard. wait_page_idle() returns after @page is idle, but that does not mean @inode is DMA idle. After one found page from dax_layout_busy_page_range() is waited upon a new call to dax_break_mapping() needs to made to check if another DMA started, or if there were originally more pages active. > + } while (error == 0); > + > + return error; Surprised that the compiler does not warn about an uninitialized variable here?