From: Daeho Jeong Date: Tue, 6 Sep 2016 02:56:10 +0000 (-0400) Subject: ext4: reinforce check of i_dtime when clearing high fields of uid and gid X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=d343ed7b8ed03c8021fb65d8c37c6479cba714b6;p=deliverable%2Flinux.git ext4: reinforce check of i_dtime when clearing high fields of uid and gid 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 --- diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c6ea25a190f8..15d4b4182ac7 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -4814,14 +4814,14 @@ static int ext4_do_update_inode(handle_t *handle, * 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));