Btrfs: Clear the device->running_pending flag before bailing on congestion
Btrfs maintains a queue of async bio submissions so the checksumming
threads don't have to wait on get_request_wait. In order to avoid
extra wakeups, this code has a running_pending flag that is used
to tell new submissions they don't need to wake the thread.
When the threads notice congestion on a single device, they
may decide to requeue the job and move on to other devices. This
makes sure the running_pending flag is cleared before the
job is requeued.
It should help avoid IO stalls by making sure the task is woken up
when new submissions come in.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index b187b53..3451e1c 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -220,6 +220,7 @@
tail->bi_next = old_head;
else
device->pending_bio_tail = tail;
+ device->running_pending = 0;
spin_unlock(&device->io_lock);
btrfs_requeue_work(&device->work);