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authorDaeho Jeong <daeho.jeong@samsung.com>2016-09-06 02:56:10 (GMT)
committerTheodore Ts'o <tytso@mit.edu>2016-09-06 02:56:10 (GMT)
commit93e3b4e6631d2a74a8cf7429138096862ff9f452 (patch)
tree722cba8354e1cdae0752583a9b23e820d500b159 /fs
parent8913f343cdb568222c95afe3cad78aee1a4df56b (diff)
downloadlinux-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.c8
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));