[PATCH] Fix commit block write in JBD2

[Jan Kara <jack@suse.cz>]

On Wed 23-01-08 20:09:43, Jan Kara wrote:
>   Hi,
> 
>   the patch below fixes preparation of commit block in
> journal_write_commit_record(). Obviously the bug doesn't really matter
> since nobody reported it so far but let's cleanup the code... Andrew, could
> you please queue it up? Thanks.
  And the same fix for JBD2.

									Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR
---

Commit block is expected to have several copies of the header. Fix the
bug Andrew has spotted ages ago.

Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c
index 6986f33..ed61283 100644
--- a/fs/jbd2/commit.c
+++ b/fs/jbd2/commit.c
@@ -116,9 +116,8 @@ static int journal_write_commit_record(journal_t *journal,
 
 	bh = jh2bh(descriptor);
 
-	/* AKPM: buglet - add `i' to tmp! */
 	for (i = 0; i < bh->b_size; i += 512) {
-		journal_header_t *tmp = (journal_header_t*)bh->b_data;
+		journal_header_t *tmp = (journal_header_t*)(bh->b_data+i);
 		tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
 		tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
 		tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);