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GET /api/patches/812700/?format=api
{ "id": 812700, "url": "http://patchwork.ozlabs.org/api/patches/812700/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ext4/patch/20170912050526.7627-2-ross.zwisler@linux.intel.com/", "project": { "id": 8, "url": "http://patchwork.ozlabs.org/api/projects/8/?format=api", "name": "Linux ext4 filesystem development", "link_name": "linux-ext4", "list_id": "linux-ext4.vger.kernel.org", "list_email": "linux-ext4@vger.kernel.org", "web_url": null, "scm_url": null, "webscm_url": null, "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20170912050526.7627-2-ross.zwisler@linux.intel.com>", "list_archive_url": null, "date": "2017-09-12T05:05:22", "name": "[v2,1/5] ext4: prevent data corruption with inline data + DAX", "commit_ref": null, "pull_url": null, "state": "accepted", "archived": true, "hash": "d276ed1bb5d7a26a826647fc831e939ed3d449be", "submitter": { "id": 46514, "url": "http://patchwork.ozlabs.org/api/people/46514/?format=api", "name": "Ross Zwisler", "email": "ross.zwisler@linux.intel.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/linux-ext4/patch/20170912050526.7627-2-ross.zwisler@linux.intel.com/mbox/", "series": [ { "id": 2615, "url": "http://patchwork.ozlabs.org/api/series/2615/?format=api", "web_url": "http://patchwork.ozlabs.org/project/linux-ext4/list/?series=2615", "date": "2017-09-12T05:05:23", "name": "ext4: DAX data corruption fixes", "version": 2, "mbox": "http://patchwork.ozlabs.org/series/2615/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/812700/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/812700/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<linux-ext4-owner@vger.kernel.org>", "X-Original-To": "patchwork-incoming@ozlabs.org", "Delivered-To": "patchwork-incoming@ozlabs.org", "Authentication-Results": "ozlabs.org;\n\tspf=none (mailfrom) smtp.mailfrom=vger.kernel.org\n\t(client-ip=209.132.180.67; helo=vger.kernel.org;\n\tenvelope-from=linux-ext4-owner@vger.kernel.org;\n\treceiver=<UNKNOWN>)", "Received": [ "from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xrt7h4zwDz9s7B\n\tfor <patchwork-incoming@ozlabs.org>;\n\tTue, 12 Sep 2017 15:06:56 +1000 (AEST)", "(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751313AbdILFGn (ORCPT <rfc822;patchwork-incoming@ozlabs.org>);\n\tTue, 12 Sep 2017 01:06:43 -0400", "from mga09.intel.com ([134.134.136.24]:5341 \"EHLO mga09.intel.com\"\n\trhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP\n\tid S1751119AbdILFFa (ORCPT <rfc822;linux-ext4@vger.kernel.org>);\n\tTue, 12 Sep 2017 01:05:30 -0400", "from fmsmga003.fm.intel.com ([10.253.24.29])\n\tby orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384;\n\t11 Sep 2017 22:05:30 -0700", "from theros.lm.intel.com ([10.232.112.77])\n\tby FMSMGA003.fm.intel.com with ESMTP; 11 Sep 2017 22:05:29 -0700" ], "X-ExtLoop1": "1", "X-IronPort-AV": "E=Sophos;i=\"5.42,381,1500966000\"; d=\"scan'208\";a=\"899352289\"", "From": "Ross Zwisler <ross.zwisler@linux.intel.com>", "To": "\"Theodore Ts'o\" <tytso@mit.edu>, Jan Kara <jack@suse.cz>,\n\tlinux-kernel@vger.kernel.org", "Cc": "Ross Zwisler <ross.zwisler@linux.intel.com>,\n\tAndreas Dilger <adilger.kernel@dilger.ca>,\n\tChristoph Hellwig <hch@lst.de>, Dan Williams <dan.j.williams@intel.com>,\n\tDave Chinner <david@fromorbit.com>, linux-ext4@vger.kernel.org,\n\tlinux-nvdimm@lists.01.org, stable@vger.kernel.org", "Subject": "[PATCH v2 1/5] ext4: prevent data corruption with inline data + DAX", "Date": "Mon, 11 Sep 2017 23:05:22 -0600", "Message-Id": "<20170912050526.7627-2-ross.zwisler@linux.intel.com>", "X-Mailer": "git-send-email 2.9.5", "In-Reply-To": "<20170912050526.7627-1-ross.zwisler@linux.intel.com>", "References": "<20170912050526.7627-1-ross.zwisler@linux.intel.com>", "Sender": "linux-ext4-owner@vger.kernel.org", "Precedence": "bulk", "List-ID": "<linux-ext4.vger.kernel.org>", "X-Mailing-List": "linux-ext4@vger.kernel.org" }, "content": "If an inode has inline data it is currently prevented from using DAX by a\ncheck in ext4_set_inode_flags(). When the inode grows inline data via\next4_create_inline_data() or removes its inline data via\next4_destroy_inline_data_nolock(), the value of S_DAX can change.\n\nCurrently these changes are unsafe because we don't hold off page faults\nand I/O, write back dirty radix tree entries and invalidate all mappings.\nThere are also issues with mm-level races when changing the value of S_DAX,\nas well as issues with the VM_MIXEDMAP flag:\n\nhttps://www.spinics.net/lists/linux-xfs/msg09859.html\n\nThe unsafe transition of S_DAX can reliably cause data corruption, as shown\nby the following fstest:\n\nhttps://patchwork.kernel.org/patch/9948381/\n\nFix this issue by preventing the DAX mount option from being used on\nfilesystems that were created to support inline data. Inline data is an\noption given to mkfs.ext4.\n\nSigned-off-by: Ross Zwisler <ross.zwisler@linux.intel.com>\nCC: stable@vger.kernel.org\n---\n fs/ext4/inline.c | 10 ----------\n fs/ext4/super.c | 5 +++++\n 2 files changed, 5 insertions(+), 10 deletions(-)", "diff": "diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c\nindex 28c5c3a..fd95019 100644\n--- a/fs/ext4/inline.c\n+++ b/fs/ext4/inline.c\n@@ -302,11 +302,6 @@ static int ext4_create_inline_data(handle_t *handle,\n \tEXT4_I(inode)->i_inline_size = len + EXT4_MIN_INLINE_DATA_SIZE;\n \text4_clear_inode_flag(inode, EXT4_INODE_EXTENTS);\n \text4_set_inode_flag(inode, EXT4_INODE_INLINE_DATA);\n-\t/*\n-\t * Propagate changes to inode->i_flags as well - e.g. S_DAX may\n-\t * get cleared\n-\t */\n-\text4_set_inode_flags(inode);\n \tget_bh(is.iloc.bh);\n \terror = ext4_mark_iloc_dirty(handle, inode, &is.iloc);\n \n@@ -451,11 +446,6 @@ static int ext4_destroy_inline_data_nolock(handle_t *handle,\n \t\t}\n \t}\n \text4_clear_inode_flag(inode, EXT4_INODE_INLINE_DATA);\n-\t/*\n-\t * Propagate changes to inode->i_flags as well - e.g. S_DAX may\n-\t * get set.\n-\t */\n-\text4_set_inode_flags(inode);\n \n \tget_bh(is.iloc.bh);\n \terror = ext4_mark_iloc_dirty(handle, inode, &is.iloc);\ndiff --git a/fs/ext4/super.c b/fs/ext4/super.c\nindex c9e7be5..4251e50 100644\n--- a/fs/ext4/super.c\n+++ b/fs/ext4/super.c\n@@ -3707,6 +3707,11 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)\n \t}\n \n \tif (sbi->s_mount_opt & EXT4_MOUNT_DAX) {\n+\t\tif (ext4_has_feature_inline_data(sb)) {\n+\t\t\text4_msg(sb, KERN_ERR, \"Cannot use DAX on a filesystem\"\n+\t\t\t\t\t\" that may contain inline data\");\n+\t\t\tgoto failed_mount;\n+\t\t}\n \t\terr = bdev_dax_supported(sb, blocksize);\n \t\tif (err)\n \t\t\tgoto failed_mount;\n", "prefixes": [ "v2", "1/5" ] }