alsa_write: Avoid hung tasks.

Without this fix the alsa writer may never shutdown, occupying a
slot of audiod. The hang was observed with in conjunction to the
udp receiver and the prebuffer filter. See also the recent commit
23913cbbfc98.

diff --git a/alsa_write.c b/alsa_write.c
index 363e393..bc06fc3 100644 (file)
--- a/alsa_write.c
+++ b/alsa_write.c
@@ -266,6 +266,8 @@ static int alsa_write_post_select(__a_unused struct sched *s, void *context)
                goto err;
 again:
        ret = btr_node_status(btrn, wn->min_iqs, BTR_NT_LEAF);
+       if (ret < 0)
+               goto err;
        if (ret == 0)
                return 0;
        btr_merge(btrn, wn->min_iqs);