Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933674AbcJUJUA (ORCPT ); Fri, 21 Oct 2016 05:20:00 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:46941 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933120AbcJUJTy (ORCPT ); Fri, 21 Oct 2016 05:19:54 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Daeho Jeong , Hobin Woo , Theodore Tso Subject: [PATCH 4.7 34/45] ext4: reinforce check of i_dtime when clearing high fields of uid and gid Date: Fri, 21 Oct 2016 11:17:54 +0200 Message-Id: <20161021091429.092099575@linuxfoundation.org> X-Mailer: git-send-email 2.10.0 In-Reply-To: <20161021091427.214431885@linuxfoundation.org> References: <20161021091427.214431885@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1929 Lines: 53 4.7-stable review patch. If anyone has any objections, please let me know. ------------------ From: Daeho Jeong commit 93e3b4e6631d2a74a8cf7429138096862ff9f452 upstream. Now, ext4_do_update_inode() clears high 16-bit fields of uid/gid of deleted and evicted inode to fix up interoperability with old kernels. However, it checks only i_dtime of an inode to determine whether the inode was deleted and evicted, and this is very risky, because i_dtime can be used for the pointer maintaining orphan inode list, too. We need to further check whether the i_dtime is being used for the orphan inode list even if the i_dtime is not NULL. We found that high 16-bit fields of uid/gid of inode are unintentionally and permanently cleared when the inode truncation is just triggered, but not finished, and the inode metadata, whose high uid/gid bits are cleared, is written on disk, and the sudden power-off follows that in order. Signed-off-by: Daeho Jeong Signed-off-by: Hobin Woo Signed-off-by: Theodore Ts'o Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4814,14 +4814,14 @@ static int ext4_do_update_inode(handle_t * Fix up interoperability with old kernels. Otherwise, old inodes get * re-used with the upper 16 bits of the uid/gid intact */ - if (!ei->i_dtime) { + if (ei->i_dtime && list_empty(&ei->i_orphan)) { + raw_inode->i_uid_high = 0; + raw_inode->i_gid_high = 0; + } else { raw_inode->i_uid_high = cpu_to_le16(high_16_bits(i_uid)); raw_inode->i_gid_high = cpu_to_le16(high_16_bits(i_gid)); - } else { - raw_inode->i_uid_high = 0; - raw_inode->i_gid_high = 0; } } else { raw_inode->i_uid_low = cpu_to_le16(fs_high2lowuid(i_uid));