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| author | Daeho Jeong <daeho.jeong@samsung.com> | 2016-09-06 02:56:10 (GMT) |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-09-06 02:56:10 (GMT) |
| commit | 93e3b4e6631d2a74a8cf7429138096862ff9f452 (patch) | |
| tree | 722cba8354e1cdae0752583a9b23e820d500b159 /fs | |
| parent | 8913f343cdb568222c95afe3cad78aee1a4df56b (diff) | |
| download | linux-93e3b4e6631d2a74a8cf7429138096862ff9f452.tar.xz | |
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.
Cc: stable@vger.kernel.org
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Hobin Woo <hobin.woo@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/ext4/inode.c | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index c6ea25a..15d4b41 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)); |