jbd2: update transaction t_state to T_COMMIT fix

Updating the current transaction's t_state is protected by j_state_lock.  We
need to do the same when updating the t_state to T_COMMIT.
Acked-by: NJan Kara <jack@suse.cz>
Signed-off-by: NMingming Cao <cmm@us.ibm.com>
Signed-off-by: N"Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>

fs/jbd2/commit.c

@@ -560,7 +560,9 @@ void jbd2_journal_commit_transaction(journal_t *journal)
 	 * transaction!  Now comes the tricky part: we need to write out
 	 * metadata.  Loop over the transaction's entire buffer list:
 	 */
+	spin_lock(&journal->j_state_lock);
 	commit_transaction->t_state = T_COMMIT;
+	spin_unlock(&journal->j_state_lock);
 
 	stats.u.run.rs_logging = jiffies;
 	stats.u.run.rs_flushing = jbd2_time_diff(stats.u.run.rs_flushing,