From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx0a-00069f02.pphosted.com (mx0a-00069f02.pphosted.com [205.220.165.32]) (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 45E7941E6A7 for ; Tue, 4 Aug 2026 07:03:50 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=205.220.165.32 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785827031; cv=fail; b=ucUlFjtN1wBtH5EtsJPltpFGjCVYz3KplkInYV/TWNxoMilRHQjchxwwFU8s1EH/P7nM26qDMBZMMQpm8vPeNCAudb2/vfWrgstdJGCkPXpf47fzJnd31kTrW0ECCLc5jndOT+hqktFEuo83/CCGF4gr6OAzS6X95yAE3W4yDGk= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785827031; c=relaxed/simple; bh=nA7wmx0qgQ4Psc3gtSCwVfrEGPGqQ395gb+yGmtlk1A=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: MIME-Version:Content-Type; b=Y+evZeDP/z8Oya7J0gZ9nTiMm4d9xf9FKIv+7VtSFJmdt+EyNM/1DdyYBuXENqLImEX7nieNkv0W4d9wCs++yze74LIQLGLjIOLRsMZO9zdlR5r9LYTichovBOw557ZLCtL1oGvbfzr3rM3tXeDIj6XM+QB8lWTweq3Qhqp6vgs= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com; spf=pass smtp.mailfrom=oracle.com; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b=la2Ni4Az; dkim=fail (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b=hh8BvkKL reason="signature verification failed"; arc=fail smtp.client-ip=205.220.165.32 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=oracle.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=oracle.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="la2Ni4Az"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=oracle.onmicrosoft.com header.i=@oracle.onmicrosoft.com header.b="hh8BvkKL" Received: from pps.filterd (m0333521.ppops.net [127.0.0.1]) by mx0b-00069f02.pphosted.com (8.18.1.11/8.18.1.11) with ESMTP id 673LCZ9G3099052; Tue, 4 Aug 2026 07:03:08 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=cc :content-transfer-encoding:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to; s= corp-2025-04-25; bh=t0oDuLhu64BuYUOkxcNBO2hi2u6IzmqTXXMZ9RzvXQM=; b= la2Ni4AzYRYXmrRuWgeqth/BGrENvqqMEt+Q2VOH7S7p+oldxLPGIz3WBuNteMO3 3aJrHGOUIyAWYTnKUMSpfiNekHAnq594foknWM7ovqd6QRI1gdki3nONMfVLleN8 LposBcfD9spxsLryAGnWvFuiamSwYYnZ998XpbkBnItOQQCZaOy/cBLZpVakjf/z /tBUx92YDx7cXNbkjKvVlt+dJjnnKe/06nRYaViEQjocOnTdYktg9wnwzwrdIVNQ PAG+77InYtkey9qVXiTjYRWfqxGcugsv3xBIEM8T1SR7OTDWqJZOWS4RrjRG84NL Rap61eeqxwhcX7EYNW2M2w== Received: from iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (iadpaimrmta03.appoci.oracle.com [130.35.103.27]) by mx0b-00069f02.pphosted.com (PPS) with ESMTPS id 4fs7qa5d14-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 04 Aug 2026 07:03:07 +0000 (GMT) Received: from pps.filterd (iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com [127.0.0.1]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (8.18.1.7/8.18.1.7) with ESMTP id 67470eLi021213; Tue, 4 Aug 2026 07:03:06 GMT Received: from sa9pr02cu001.outbound.protection.outlook.com (mail-southcentralusazon11013017.outbound.protection.outlook.com [40.93.196.17]) by iadpaimrmta03.imrmtpd1.prodappiadaev1.oraclevcn.com (PPS) with ESMTPS id 4fs78srs8w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Tue, 04 Aug 2026 07:03:06 +0000 (GMT) ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=cvdVaeT5lg+loKc5Lm0xpy6PzEUicrYHicZy1dspbr9glLV39ZUaivBG++wWSX0segk3i8Dj8QLpuqYWEXSM2CJ8i+G6j1Emz2gLH9sEwWFtFrYJrPf94AG9bY/C9IiNltpSRHXhakBq2rmULPStuZKN7y+2zeHE9IzYDUc9larTu+BlfHhjYe6fFBEBlKWv+L95A7H/IoWQqimxOVZGWCSWBHc3eleU0llXDOBf1J5DQsoJNrb7sqUdC5kicUiPRx36oLuV/5FCQhbhjn7yA+zxPDRHHzezo6cH26I0CwA5eTZ/7osGT5qwVROS8Rird56Fq1iqzDu3FPzbVV8UiQ== 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=SCIVMVBGOFoOlSGnIHBKkMOdDXixXzGhKO/G37Qe9uw=; b=Odcbh8HLDxeCZV+opAGEOl1fO+VsTchXmxocSt165SgYmPvjaIpj6aN/62o3YfUYK649DFVon+RxT+x8cw0H2v+ZRCpRWeF6t5uWnABMF4xPFAVVHAQMRKq2jVoAzRAgeauxFHD18XX5kejEzeyYDD+6B/MTI7CWZmbeZX4DaamSMs6aAOZWMorHtYsMA0uISfnrZ5E36z0xIk8zaUZK9b+rBmjGnfifZ8ccqOvhCHiwRAOlS/DT2tq5MOrbSNjoKT6+H0xiE0KH8aY0fCXWfH9ResxoSL8wmWD91W8NZ+YI/vwS58cU9j71KY2jCrI97Zm33doXBjCezmqKv/Qwqg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=oracle.com; dmarc=pass action=none header.from=oracle.com; dkim=pass header.d=oracle.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.onmicrosoft.com; s=selector2-oracle-onmicrosoft-com; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=SCIVMVBGOFoOlSGnIHBKkMOdDXixXzGhKO/G37Qe9uw=; b=hh8BvkKLAD0R+xsQH4Zfs/ia6tXlAvQreCvgwPk6JuOYytqTFemcBxZ63GTUSx5gKMi++Jvem7IVybccpjNkb0mKGjgQgoK5gZXF+RD/7rBcEfgDeep7pRhxSLkJRKutnwx+FXTu4IgjH1FDn78J8isbX33sS4wr1sAOMHIZpqI= Received: from IA0PR10MB7369.namprd10.prod.outlook.com (2603:10b6:208:40e::14) by DM3PPF1652C44C3.namprd10.prod.outlook.com (2603:10b6:f:fc00::c0b) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.270.17; Tue, 4 Aug 2026 07:02:59 +0000 Received: from IA0PR10MB7369.namprd10.prod.outlook.com ([fe80::bef9:7d0a:4382:978e]) by IA0PR10MB7369.namprd10.prod.outlook.com ([fe80::bef9:7d0a:4382:978e%6]) with mapi id 15.21.0270.016; Tue, 4 Aug 2026 07:02:59 +0000 Message-ID: <5776d0b2-3bfe-49ac-b771-8021aaba409e@oracle.com> Date: Tue, 4 Aug 2026 00:02:50 -0700 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v8 14/15] filemap: Add support for authoritative mappings Content-Language: en-US To: "Matthew Wilcox (Oracle)" , Andrew Morton , linux-mm@kvack.org Cc: Muchun Song , Oscar Salvador , David Hildenbrand , Miaohe Lin , Naoya Horiguchi , Jan Kara , linux-fsdevel@vger.kernel.org, Christian Brauner , Jiaqi Yan References: <20260731200802.574821-1-willy@infradead.org> <20260731200802.574821-15-willy@infradead.org> From: jane.chu@oracle.com In-Reply-To: <20260731200802.574821-15-willy@infradead.org> X-ClientProxiedBy: PH7PR10CA0014.namprd10.prod.outlook.com (2603:10b6:510:23d::16) To IA0PR10MB7369.namprd10.prod.outlook.com (2603:10b6:208:40e::14) Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR10MB7369:EE_|DM3PPF1652C44C3:EE_ X-MS-Office365-Filtering-Correlation-Id: b78b5baf-81df-46f1-49a5-08def1f66b22 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|1800799024|7416014|376014|23010399003|18002099003|22082099003|4143699003|56012099006|4133799003|10067099003; X-Microsoft-Antispam-Message-Info: IfPQhn47rBC9VNSXWy/nduYxkf0I3lNMRpsXy/0YmwPn2EV3lUoGe1uIBftIOB+IXR9uos+JctS4btK7M5KwDx5svC1dgyETdXCLLkjizsf+LuP/KDx1XaDmOVzDPbQn0z4TAkf6iIWtmxn9zFMrTC6oDZpAUYjB121pFrJ4/YkNDAlVstBWiNLod96kVIw1nY3rb0WhgxKdhwfur5wu2Jc0cuFRlLFIdX1a72iWFXmteHHqqbL/f/fMNrum0S45JR9ZDr6LhC52cOgKpGdbkc/J9xCb1wMLJLD1RZXhZGHBkAUzZm20Z/mqJI+3tXCOhJgxt77C8hHNObQXm5iAOmbDt2Hf6mxa9VB2l2LBooM1rIHzecrjzA+hC2seYw1372JBm4tXjB2TZmUlI0NXOv4TlUVKfoFtddoJMyjgYPvppAddkwf/W3jOpFG9CftLYeGEu6ZHmI4xrRqXNst/FGdvkcjPeDKo7pKQodiE0YUfC6V866K0RPXhUT+09PdJp3INVUESsxBeOFPz1TjlJfC8vHm4bxfXZ+x0RjLiSy+wNjUxXU2hv5Cqs53k5YtDNjAAmYfKXsIDq1T1yNO1OrOHyWLCkRtwNLdPuvm/tDiV+mPdhJsCbi0LdvB3uqqYb1hDu7qRio7cOIrwTZ25PPXHuCxvgKX1tMSIKwWY7bo= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:IA0PR10MB7369.namprd10.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(1800799024)(7416014)(376014)(23010399003)(18002099003)(22082099003)(4143699003)(56012099006)(4133799003)(10067099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?N2JMTzFjMTRoeFpyWUl4cDFyZEVTR3RpU3VNaVpKeStRUzhua1pHRHNodG9t?= =?utf-8?B?VE9GcE1OU0tqUGJlZkRXbGE3UkJNUEtZQUgxTklyMFUzcnlwYy9aNEZLOUlI?= =?utf-8?B?V0VLMElBeEl1L3FzTHErUmFZS0xmdDVCaWk4bDBSbXJzTTd1b0tzTUovTGdx?= =?utf-8?B?b3d2Nkh2dG13Wlk4eWVkNjQzUGV1MmpxcGZRazcvRzFuOERFQlJXMGwxa0sw?= =?utf-8?B?YXUySGxTVjBSeFBTc1BuSXdVZUhJdEpkR2dmbi9QWm5Ra3BRdFRHaWJDZUh0?= =?utf-8?B?N3ZLVXQ4UEFETzVIODZ5ODdka1BsYjdVZG9tZTZ4Q0FSaENWMVJJdkNoTWZk?= =?utf-8?B?bGV4ejgzL1VybDYrdGVGamVqNGJKdXFSSDBmeFpKeXpjZUZScUVyRkJEOGxM?= =?utf-8?B?RkxaRUtOMThYYUZTN3UycFhTSEZlWm1kYUxGYXcxZTh3eU8yWGZmL3djRFlR?= =?utf-8?B?MkxzYWJvTFZ4Z2lNTFFXNDFneFF5NHN5Z1J1ZUhzSnRoZmtVb3RjNGJKallG?= =?utf-8?B?czh0RGhxQXlUS1RiT2dnVkt0Vmt4SktIbW1GSEo2bnVmYUhpeUsySTFPVTN2?= =?utf-8?B?UFEwZHdqZXNXRlNSMXRMTVI0c1ZCS0tFd1MwTG9ET3dwTTJBeWFWQTBzdXJm?= =?utf-8?B?Y0F2MC91alZEZWtURmw2ekUvMUdHUlcyMmQ4TW14cUp6MTZWZ2RVY2t1eW1z?= =?utf-8?B?UU95RCtBSXFQaG96NjNDUjdWclBGL3cyTzdNaXRqTDF2M1dLcDdRdmJieUxX?= =?utf-8?B?d0c4QUxqWWhjUEVwRE53UFN2ektnWEM1SXBZS2Z5amNCSE9nMDNTVWZGMUpS?= =?utf-8?B?RTFpNFhTNTBReFo4MndGVzhiRW5Rd0M0eGhDbjJGWnpiWWRJMEFKL1pWQ2tm?= =?utf-8?B?TzU3MkxWMnFublhkYXBUMmQyQTFJRjZhTEZrYWNXL0tiMURBU0FYOFVPL2dZ?= =?utf-8?B?SEhRdFFGcUdOclRFenY2NkZZbm9oSGJkS08vN2FoT05CNDI1R2RRT29hb3Fi?= =?utf-8?B?bFErbDdZb0x1amkzVFVwQmFIZmpIcFJYbzhTeWIxRGZacEtIMFFaQUZHNFZy?= =?utf-8?B?YmgzMk1BWEpPeW9ER2QyYjllVDVWRHQrOU0zaUxPV1VPc3J0anlyYnlqSDZP?= =?utf-8?B?cDBaaElWMjJWWVZQSGZEZFR2d0s0OHRYQTFwcnJZd0lVUlFFbzZEM1VnUTVs?= =?utf-8?B?UGFrS2JiN3F4VjR1NUZCakFVeGQwL3BZUUY1UTY3NjZPYnFuaGdCcWZoUkwy?= =?utf-8?B?dGJqZjdlZ2x4VWhNRXpxWnljdlVFRTJoSHluRXAxbmJyR3NjTU9iZDFjb2g5?= =?utf-8?B?RGxVRVkzN0xGTVJWNnFNQnQvUGJMVTBwZ016ZWZ3Ni9idkZHV2ZINEJGeEpu?= =?utf-8?B?elovR1c1Wk83MkgwQTZjWlBvUVQ1SHh1SEtrWkp3Uzgxb0FqOUVwS3FKTWNw?= =?utf-8?B?NGkwcjlDMU16K2JLYzhPMmpsRHRiMlkvNGFzbzlpOEVPMlduN01sRUVkWWVP?= =?utf-8?B?UGtsS2NNMEFpS1laV01FQVcxandSZml5b0NuUENCVi84N1pMdGVteFQzaG8r?= =?utf-8?B?SlZJMExST3IzVjZuaVlBSWQ0RmlWQUdBRE1ZRS85T21NYzdENVN1QzR1VTVR?= =?utf-8?B?ZWVZbEt4MzVLcHNLVXVWOFJ3b3loMkIrS1lEeHNZYStoVkJzcW1saGRSQTZi?= =?utf-8?B?aHJNcjBlQ2lUZWtwckhGRWdZa1RoTjVLMURCOGdOV1ZQSVJYQ0Z3V0ZLRHBD?= =?utf-8?B?S2YwZG9TMWIxU3JINEQ1UlUzTk0wZmRkRElha3YySkl1YWdBdi82d2JXT2xa?= =?utf-8?B?WTF2amN2dFJVb0hLKzY2MXFCeUxJejJXY3ZCVzhxZW9rMk5SVmtlY04rVmJk?= =?utf-8?B?Q0MzN2UxNm1YYzFWY2c1aTRZNThNZ084SFhQbEkveDdqdDlKdnhrUElaUzB3?= =?utf-8?B?Z05TVmhXeHl0eWlWSWllNEVCS3hVcG9iVUQ0c3R3YlVpanRsRDV2eGVhcVJr?= =?utf-8?B?NEM1bUZlampqdmN2QXFJWXVnOW9jMjdTeWhwczU0enFRbTVlTjRrbjVLbnU0?= =?utf-8?B?UHp3Q05Md01wOVVybUh1M3hocCtaTGRoSkR1TkNLRmNYZCtUVFBhTzlMams1?= =?utf-8?B?VTh1MENtaUlFcStYYzZOWC9qYXV3SmZNY2JFSjRiK21EeHVBNHhrYWF1UCtH?= =?utf-8?B?K3p6ZU5uc29XWUZkNmI2Ry9IdVRhditJSnJWZVc2YzVUbXY4OUJjMU5RbHZm?= =?utf-8?B?WUx1YWU0K0JiTFY3V0tXb0pWWFpMZE5SS01Yd1dOK0x5Q2pSelZpcGRmNXBJ?= =?utf-8?B?dWZra2dqR0dNWTRDTnNxNHZuTTc2OWJPZ25KZ09FOEtQQ0tTblhudz09?= X-Exchange-RoutingPolicyChecked: SDlVC6xTLoJej2yZ3DSfdU/n5gplJYXQaB4fVxUqLYSLfhQEr8dRNzTklcSKJ1D8tLW2oYDvx20gVJAShCZJNPXNVya0hoPTfPWMHOEHjXr0RJkq95bd1XOGGkMFtgFcjryYlktOOx8ERgRrhlxilPUZ27pYdBrhJUGvRYNOyrHFafIDxDh9hAx28T4EaOO8Lo4ADf638ORyKm2gQ0MEtD0QvSVIEOWCLCurTRlD2Xaa1gGFitaQ+7suaVzPxIFU4TrqlarMMoH5HNkL3qLve4vbZ2QGKWPAXPsmQyiT9bvLubU5jnHT/6HHPp8CvCZj9COwJ+5qHBhbx9AHL+Tg2Q== X-MS-Exchange-AntiSpam-ExternalHop-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-ExternalHop-MessageData-0: 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 X-OriginatorOrg: oracle.com X-MS-Exchange-CrossTenant-Network-Message-Id: b78b5baf-81df-46f1-49a5-08def1f66b22 X-MS-Exchange-CrossTenant-AuthSource: IA0PR10MB7369.namprd10.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 04 Aug 2026 07:02:59.6621 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 4e2c6054-71cb-48f1-bd6c-3a9705aca71b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Q0HReatbH54Kw+H/CK1/4bVk//tTPKsx06gZ8ZafAyUKh6GXIF57jejXHNIw9lB9Xoy9k/7+7gUQrRjp2jbpgA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM3PPF1652C44C3 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-04_01,2026-08-03_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 malwarescore=0 spamscore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 mlxlogscore=999 mlxscore=0 phishscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2606160000 definitions=main-2608040054 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODA0MDA1NCBTYWx0ZWRfX9n+Qkiv+gW5X VaZIke7FTYc5Han/IBfuhQMFi9isku+aMqMq9xda4h4vk7pxVg6tlHDxCsXZdgGrGYxmGzmcmJu c5YRBJlNM9VrYjDqTlYBemLz3/eix9+dayh6BE+nmoKbFvoM/avWz8L9h/vzmxUTAk7EBl7YbxD yf/++j6s5aDwWMJBAI76iNN3CPSCgLQE+PZCE/WjKfK3dspHuol0MT8Wv2ap3bH6801nhfKVd0l f3T74cZfXMkx1XzKBrgp/UYO+IyiQPCLGZuGoVNwgY1BfKa4oKT3lyhgfi99YxBisuol/VJLOTL +U6g9H88T6rTwvXXaqgBcJ9c6Jbp7GTTdwAQcJgKfdm8kNwlLcAhEaS6IL+NKVCMU4hzGcNbrIl 2UH7f8mld3Z3GPSe9ofbAUc06YgtRwh3b7ara9kqmNnF2TVb8qOxrhUGy0GlXPEK5FTQuzeVJR/ jO/rQw6M6fsg+ZaCGjIqt52MM2cw/FzI7Y4/dXt4= X-Proofpoint-GUID: OCtxD5pU1JBtgzw_5alHLiJwx6uUuCxN X-Authority-Analysis: v=2.4 cv=frDsol4f c=1 sm=1 tr=0 ts=6a718eab b=1 cx=c_pps a=qoll8+KPOyaMroiJ2sR5sw==:117 a=qoll8+KPOyaMroiJ2sR5sw==:17 a=6eWqkTHjU83fiwn7nKZWdM+Sl24=:19 a=z/mQ4Ysz8XfWz/Q5cLBRGdckG28=:19 a=lCpzRmAYbLLaTzLvsPZ7Mbvzbb8=:19 a=xqWC_Br6kY4A:10 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=GoEa3M9JfhUA:10 a=VkNPw1HP01LnGYTKEx00:22 a=jiCTI4zE5U7BLdzWsZGv:22 a=x0eKOSpe3m1H3M0S9YoZ:22 a=RpNjiQI2AAAA:8 a=JfrnYn6hAAAA:8 a=yPCof4ZbAAAA:8 a=8dRQpW5Z0ZQAO81WL6sA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=1CNFftbPRP8L7MoqJWF3:22 a=5yU3S35YU4bGjq-dph-N:22 a=Bho9c0fBagfJEIQBS7DQ:22 cc=ntf awl=host:12101 X-Proofpoint-ORIG-GUID: OCtxD5pU1JBtgzw_5alHLiJwx6uUuCxN X-Proofpoint-Spam-Info: AW1haW4tMjYwODA0MDA1NCBTYWx0ZWRfX2IRP8LAvZjJT LLpleJivvIS6kPlXy3pykv2WRY7o7B2FRUsAz/DzyAQcPYb7Uv034zszgk5rgmeWWiDahU/5Ise JhMxonK9GAs4v8hhndm54RZEEDf5CCBP4jjTAEbWAwZzHAWzkitd On 7/31/2026 1:07 PM, Matthew Wilcox (Oracle) wrote: > An authoritative mapping knows about all the folios in the mapping. If=20 > read() finds a missing folio, there's no reason to allocate one and try=20 > to read it because we know it's a zero region of the file. We can just=20 > call iov_iter_zero() instead.=E2=80=8A >=20 >=20 > An authoritative mapping knows about all the folios in the mapping. > If read() finds a missing folio, there's no reason to allocate one and > try to read it because we know it's a zero region of the file. We can > just call iov_iter_zero() instead. >=20 > Signed-off-by: Matthew Wilcox (Oracle) > --- > include/linux/pagemap.h | 11 +++++++++++ > mm/filemap.c | 18 ++++++++++++++++++ > 2 files changed, 29 insertions(+) >=20 > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 968b791cfd14..22d48935ffda 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -210,6 +210,7 @@ enum mapping_flags { > AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM =3D 9, > AS_KERNEL_FILE =3D 10, /* mapping for a fake kernel file that shouldn't > account usage to user cgroups */ > + AS_AUTHORITATIVE =3D 11, /* If we miss in the page cache, it's a hole */ > /* Bits 16-25 are used for FOLIO_ORDER */ > AS_FOLIO_ORDER_BITS =3D 5, > AS_FOLIO_ORDER_MIN =3D 16, > @@ -345,6 +346,16 @@ static inline bool mapping_writeback_may_deadlock_on= _reclaim(const struct addres > return test_bit(AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM, &mapping->flags); > } > =20 > +static inline void mapping_set_authoritative(struct address_space *mappi= ng) > +{ > + set_bit(AS_AUTHORITATIVE, &mapping->flags); > +} > + > +static inline bool mapping_is_authoritative(const struct address_space *= mapping) > +{ > + return test_bit(AS_AUTHORITATIVE, &mapping->flags); > +} > + > static inline gfp_t mapping_gfp_mask(const struct address_space *mappin= g) > { > return mapping->gfp_mask; > diff --git a/mm/filemap.c b/mm/filemap.c > index 26a5f18121f9..5a8cc20e624e 100644 > --- a/mm/filemap.c > +++ b/mm/filemap.c > @@ -2697,6 +2697,8 @@ static int filemap_get_pages(struct kiocb *iocb, si= ze_t count, > if (!folio_batch_count(fbatch)) { > DEFINE_READAHEAD(ractl, filp, &filp->f_ra, mapping, index); > =20 > + if (mapping_is_authoritative(mapping)) > + return 0; > if (iocb->ki_flags & IOCB_NOIO) > return -EAGAIN; > if (iocb->ki_flags & IOCB_NOWAIT) > @@ -2853,6 +2855,22 @@ ssize_t filemap_read(struct kiocb *iocb, struct io= v_iter *iter, > goto put_folios; > end_offset =3D min_t(loff_t, isize, iocb->ki_pos + iter->count); > =20 > + if (!folio_batch_count(&fbatch)) { > + size_t fsize =3D mapping_min_folio_nrbytes(mapping); > + size_t offset =3D iocb->ki_pos & (fsize - 1); > + size_t bytes =3D min_t(loff_t, end_offset - iocb->ki_pos, > + fsize - offset); > + size_t copied =3D iov_iter_zero(bytes, iter); > + > + already_read +=3D copied; > + iocb->ki_pos +=3D copied; > + last_pos =3D iocb->ki_pos; > + > + if (copied < bytes) > + error =3D -EFAULT; > + continue; > + } > + > /* > * Once we start copying data, we don't want to be touching any > * cachelines that might be contended: > --=20 > 2.47.3 >=20 Very nice change. Reviewed-by: Jane Chu thanks, -jane