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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?RwaQe51A8E+DMKRTKou/Bqts6u9vBTCiZet1VzBB9sevFaqXBPVcGHuc+m2c?= =?us-ascii?Q?oPhrqj2Vo1aF/05szHAGOtJ0V3dnxlVwIeEulNXCCLtfAnIy/vyfFFvPBkxP?= =?us-ascii?Q?UF+6ZqIKOCd5CUvfdep50lO1sNodl1hrGuTx5Bjv4dwxqE5T5/8MvNy//OXY?= =?us-ascii?Q?XyFuHRLay72YiJ11DTPlYUun7Dmn0yC4bVWk53QSn0Gyhx7HRiZ1Hfa9OQ46?= =?us-ascii?Q?oyvTg5KKHR4wxfAaKNrD+Xib5K3Sd8tnT/+AONSbJvY+yYPO5XU/QHwydUDW?= =?us-ascii?Q?e2f67vQRndK+QHqdyY54I091sZ0AHSnU4fVztD5wG6hbArHhduB8/g6TlXWD?= =?us-ascii?Q?MferJjsDJ7ofgkzkvmbjx+Cvy4nZUP0vM3j3gkGVE9/9nUfgss4DYbiEbvfH?= =?us-ascii?Q?6cvCRslyHIZtR3p/U3tu4mpLn43kmiT1Teo6uASaLMijnsl7mHIoKCdM5DCT?= =?us-ascii?Q?xBIWkcz98AyvKe2idZyOrpOW1lSOXRVi5B6E31fdOiTFncboff8pzjjT0OYZ?= =?us-ascii?Q?qYFT26JtKRULcH/BeKr1LYEvxpbvQTVAJvNmZtTNGZJ9cEKG+/GhtudiYkyb?= =?us-ascii?Q?L/zD8EVmCd1trh5/sliT+WqtO4RYHNfSy63b4vs6xfsQwHcIPaL8WP208R9U?= =?us-ascii?Q?0HeeROBSzjkSG4lNzntOdHz76sOEiB3Wk/68oNVcQlfvrOz+qJvh6BKMdmE9?= =?us-ascii?Q?mc8/psg8KX21v8LIf7klqqllNUkfGmv+TDF6X5fXfw5OlmOYFPu6WdEn2eL/?= =?us-ascii?Q?cAFnJxI+zrNTRHhFLgeMrdwH9pBog12aHjO5ViTlKzMGixe5IgJJHmsnwnU9?= =?us-ascii?Q?xXbWQJD1jTidh4gj46Dr/VMjJoNoJG+WLlxAMyiTVkQt/k6DclE7/HCzG70l?= =?us-ascii?Q?uKf8n2zKRqIKX6ZKYCbd5uIB4ZldSTj1Fmcas3NS4u+f4IZELZj+WtphCBkF?= =?us-ascii?Q?OywVpuP3LFnzpcFOaMTJjcQevv2L8VEU5ujFUwUxRWEoFzCOlqUDRo2o9l96?= =?us-ascii?Q?stBAIFi3NDzHL4RFY0tekwmjqVDC2CXZ7y4+sUMUSjh1AKAA/Wf4JdUBapXd?= =?us-ascii?Q?d6t4dy2vWxMmxqI/dhN6G0KNzhPpGmqKUJS1XuYYdXUT/UnrACbwm6wikAjC?= =?us-ascii?Q?tVHBw8f3sYpfPsNzQYwILMSQS52EbWs+yU/Z8jwovl359ewtgvMO7dNeJ1Rf?= =?us-ascii?Q?Ofc7M3anunU7zrglDRqfYTR8tUmTQxT/+i2yCjAa+fQbM8os4STSaM+xJn2r?= =?us-ascii?Q?w8IfK/MgvoLO2lHJFY65XB2DJn99USL/1AhBTg6RqeJBbYc1sLf/KDgHboz8?= =?us-ascii?Q?SmvoDzz3YjKAQ8LGhYHX72T4EuFfn79EJZS+5VVMH9iiqA=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 5393f367-45d8-47d5-9894-08d94ae4ff98 X-MS-Exchange-CrossTenant-AuthSource: BYAPR15MB4136.namprd15.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 19 Jul 2021 18:42:45.2324 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ae927fe-1255-47a7-a2af-5f3a069daaa2 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Lq2ClsSPsrPSFM96R5S89UPiuitkBK0MmhUqdiCggG6xpGohaMg0+47kheUV5dNo X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR15MB2712 X-OriginatorOrg: fb.com X-Proofpoint-ORIG-GUID: qGdIwYBSoS0IILHjXDmbUmkl_0jXQQHT X-Proofpoint-GUID: qGdIwYBSoS0IILHjXDmbUmkl_0jXQQHT X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-07-19_09:2021-07-19,2021-07-19 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 priorityscore=1501 impostorscore=0 lowpriorityscore=0 bulkscore=0 spamscore=0 adultscore=0 suspectscore=0 phishscore=0 mlxscore=0 mlxlogscore=677 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104190000 definitions=main-2107190106 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Mon, Jul 19, 2021 at 07:13:26PM +0100, Matthew Wilcox wrote: > On Mon, Jul 19, 2021 at 10:13:50AM -0700, Roman Gushchin wrote: > > The inode switching code is not suited for dax inodes. An attempt > > to switch a dax inode to a parent writeback structure (as a part > > of a writeback cleanup procedure) results in a panic like this: > [...] > > The crash happens on an attempt to iterate over attached pagecache > > pages and check the dirty flag: a dax inode's xarray contains pfn's > > instead of generic struct page pointers. > > I wondered why this happens for DAX and not for other kinds of non-page > entries in the inodes. The answer is that it's a tagged iteration, and > shadow/swap entries are never tagged; only DAX entries get tagged. Indeed! A good note. > > Acked-by: Matthew Wilcox (Oracle) > Thank you!