jbd: need to hold j_state_lock to updates to transaction t_state to T_COMMIT

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.

Signed-off-by: Mingming Cao <[e-mail]>
Acked-by: Jan Kara <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

fs/jbd/commit.c

···
 	 * 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);
 
 	J_ASSERT(commit_transaction->t_nr_buffers <=
 		 commit_transaction->t_outstanding_credits);