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 <chris.mason@oracle.com>

fs/btrfs/async-thread.c

@@ -377,6 +377,7 @@ again:
 				if (!list_empty(&worker->pending) ||
 				    !list_empty(&worker->prio_pending)) {
 					spin_unlock_irq(&worker->lock);
+					set_current_state(TASK_RUNNING);
 					goto again;
 				}