Don't allow too much data buffers in a transaction.

diff --git a/fs/jbd/transaction.c b/fs/jbd/transaction.c
index 08ff6c7..e6f9dd6 100644
--- a/fs/jbd/transaction.c
+++ b/fs/jbd/transaction.c
@@ -163,7 +163,7 @@ repeat_locked:
 	spin_lock(&transaction->t_handle_lock);
 	needed = transaction->t_outstanding_credits + nblocks;
 
-	if (needed > journal->j_max_transaction_buffers) {
+	if (needed > journal->j_max_transaction_buffers || atomic_read(&transaction->t_data_buf_count) > 32768) {
 		/*
 		 * If the current transaction is already too large, then start
 		 * to commit it: we can then go back and attach this handle to
@@ -1528,6 +1528,7 @@ static void __journal_temp_unlink_buffer(struct journal_head *jh)
 		return;
 	case BJ_SyncData:
 		list = &transaction->t_sync_datalist;
+		atomic_dec(&transaction->t_data_buf_count);
 		break;
 	case BJ_Metadata:
 		transaction->t_nr_buffers--;
@@ -1989,6 +1990,7 @@ void __journal_file_buffer(struct journal_head *jh,
 		return;
 	case BJ_SyncData:
 		list = &transaction->t_sync_datalist;
+		atomic_inc(&transaction->t_data_buf_count);
 		break;
 	case BJ_Metadata:
 		transaction->t_nr_buffers++;
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index d9ecd13..6dd284a 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -541,6 +541,12 @@ struct transaction_s
 	int			t_outstanding_credits;
 
 	/*
+	 * Number of data buffers on t_sync_datalist attached to
+	 * the transaction.
+	 */
+	atomic_t		t_data_buf_count;
+
+	/*
 	 * Forward and backward links for the circular list of all transactions
 	 * awaiting checkpoint. [j_list_lock]
 	 */