Btrfs: don't walk around with task->state != TASK_RUNNING

Yan Zheng noticed two places we were doing a lot of work
without task->state set to TASK_RUNNING. This sets the state
properly after we get ready to sleep but decide not to.

Signed-off-by: Chris Mason <[e-mail]>

fs/btrfs/async-thread.c

···
 				if (!list_empty(&worker->pending) ||
 				    !list_empty(&worker->prio_pending)) {
 					spin_unlock_irq(&worker->lock);
+					set_current_state(TASK_RUNNING);
 					goto again;
 				}
 

fs/btrfs/transaction.c

···
 			snap_pending = 1;
 
 		WARN_ON(cur_trans != trans->transaction);
-		prepare_to_wait(&cur_trans->writer_wait, &wait,
-				TASK_UNINTERRUPTIBLE);
-
 		if (cur_trans->num_writers > 1)
 			timeout = MAX_SCHEDULE_TIMEOUT;
 		else if (should_grow)
···
 		 * to the list
 		 */
 		btrfs_run_ordered_operations(root, 1);
+
+		prepare_to_wait(&cur_trans->writer_wait, &wait,
+				TASK_UNINTERRUPTIBLE);
 
 		smp_mb();
 		if (cur_trans->num_writers > 1 || should_grow)