ext4: remove erroneous ext4_superblock_csum_set() in update_backups()

commit bef53b01faeb791e27605cba1a71ba21364cb23e upstream.

The update_backups() function is used to backup all the metadata
blocks, so we should not take it for granted that 'data' is pointed to
a super block and use ext4_superblock_csum_set to calculate the
checksum there.  In case where the data is a group descriptor block,
it will corrupt the last group descriptor, and then e2fsck will
complain about it it.

As all the metadata checksums should already be OK when we do the
backup, remove the wrong ext4_superblock_csum_set and it should be
just fine.

Reported-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c
index 101b41c6844c9f942f98e535bd7da51bde0b8f81..82e1fde3e0ef3880b64d926075d10e74b5b56445 100644 (file)
--- a/fs/ext4/resize.c
+++ b/fs/ext4/resize.c
@@ -979,8 +979,6 @@ static void update_backups(struct super_block *sb,
                goto exit_err;
        }
 
-       ext4_superblock_csum_set(sb);
-
        while ((group = ext4_list_backups(sb, &three, &five, &seven)) < last) {
                struct buffer_head *bh;