{"id":812700,"url":"http://patchwork.ozlabs.org/api/patches/812700/?format=json","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=json","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=json","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=json","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":"","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=)","Received":["from vger.kernel.org (vger.kernel.org [209.132.180.67])\n\tby ozlabs.org (Postfix) with ESMTP id 3xrt7h4zwDz9s7B\n\tfor ;\n\tTue, 12 Sep 2017 15:06:56 +1000 (AEST)","(majordomo@vger.kernel.org) by vger.kernel.org via listexpand\n\tid S1751313AbdILFGn (ORCPT );\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 );\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 ","To":"\"Theodore Ts'o\" , Jan Kara ,\n\tlinux-kernel@vger.kernel.org","Cc":"Ross Zwisler ,\n\tAndreas Dilger ,\n\tChristoph Hellwig , Dan Williams ,\n\tDave Chinner , 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":"","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 \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"]}