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| author | Daeho Jeong <daeho.jeong@samsung.com> | 2016-07-04 00:51:39 +0300 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2016-07-04 00:51:39 +0300 |
| commit | b47820edd1634dc1208f9212b7ecfb4230610a23 (patch) | |
| tree | 7d02e4756db46ae94ec43fdcd1adfd38156e34a5 /fs/ext4/namei.c | |
| parent | f70749ca42943faa4d4dcce46dfdcaadb1d0c4b6 (diff) | |
| download | linux-b47820edd1634dc1208f9212b7ecfb4230610a23.tar.xz | |
ext4: avoid modifying checksum fields directly during checksum verification
We temporally change checksum fields in buffers of some types of
metadata into '0' for verifying the checksum values. By doing this
without locking the buffer, some metadata's checksums, which are
being committed or written back to the storage, could be damaged.
In our test, several metadata blocks were found with damaged metadata
checksum value during recovery process. When we only verify the
checksum value, we have to avoid modifying checksum fields directly.
Signed-off-by: Daeho Jeong <daeho.jeong@samsung.com>
Signed-off-by: Youngjin Gil <youngjin.gil@samsung.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Diffstat (limited to 'fs/ext4/namei.c')
| -rw-r--r-- | fs/ext4/namei.c | 9 |
1 files changed, 4 insertions, 5 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index ec4c39952e84..5bb46b6ed456 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -420,15 +420,14 @@ static __le32 ext4_dx_csum(struct inode *inode, struct ext4_dir_entry *dirent, struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); struct ext4_inode_info *ei = EXT4_I(inode); __u32 csum; - __le32 save_csum; int size; + __u32 dummy_csum = 0; + int offset = offsetof(struct dx_tail, dt_checksum); size = count_offset + (count * sizeof(struct dx_entry)); - save_csum = t->dt_checksum; - t->dt_checksum = 0; csum = ext4_chksum(sbi, ei->i_csum_seed, (__u8 *)dirent, size); - csum = ext4_chksum(sbi, csum, (__u8 *)t, sizeof(struct dx_tail)); - t->dt_checksum = save_csum; + csum = ext4_chksum(sbi, csum, (__u8 *)t, offset); + csum = ext4_chksum(sbi, csum, (__u8 *)&dummy_csum, sizeof(dummy_csum)); return cpu_to_le32(csum); } |