This is a note to let you know that I've just added the patch titled ext4: reinforce check of i_dtime when clearing high fields of uid and gid to the 4.7-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ext4-reinforce-check-of-i_dtime-when-clearing-high-fields-of-uid-and-gid.patch and it can be found in the queue-4.7 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 93e3b4e6631d2a74a8cf7429138096862ff9f452 Mon Sep 17 00:00:00 2001 From: Daeho Jeong <daeho.jeong@xxxxxxxxxxx> Date: Mon, 5 Sep 2016 22:56:10 -0400 Subject: ext4: reinforce check of i_dtime when clearing high fields of uid and gid From: Daeho Jeong <daeho.jeong@xxxxxxxxxxx> 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 <daeho.jeong@xxxxxxxxxxx> Signed-off-by: Hobin Woo <hobin.woo@xxxxxxxxxxx> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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)); Patches currently in stable-queue which might be from daeho.jeong@xxxxxxxxxxx are queue-4.7/ext4-reinforce-check-of-i_dtime-when-clearing-high-fields-of-uid-and-gid.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html