drbd: Work on the Ahead -> SyncSource transition

The test if rs_pending_cnt == 0 was too weak. Using Test for
unacked_cnt == 0 instead. Moved that into the worker.

Since unacked_cnt gets already increased when an P_RS_DATA_REQ
comes in.

Also using a timer to make Ahead -> SyncSource -> Ahead cycles
slower...

Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c
index 147f76b26810..3a95b701b5d0 100644
--- a/drivers/block/drbd/drbd_worker.c
+++ b/drivers/block/drbd/drbd_worker.c
@@ -712,10 +712,24 @@ static int w_make_ov_request(struct drbd_conf *mdev, struct drbd_work *w, int ca
 }
 
 
+void start_resync_timer_fn(unsigned long data)
+{
+        struct drbd_conf *mdev = (struct drbd_conf *) data;
+
+        drbd_queue_work(&mdev->data.work, &mdev->start_resync_work);
+}
+
 int w_start_resync(struct drbd_conf *mdev, struct drbd_work *w, int cancel)
 {
-        drbd_start_resync(mdev, C_SYNC_SOURCE);
+        if (atomic_read(&mdev->unacked_cnt) || atomic_read(&mdev->rs_pending_cnt)) {
+                dev_warn(DEV, "w_start_resync later...\n");
+                mdev->start_resync_timer.expires = jiffies + HZ/10;
+                add_timer(&mdev->start_resync_timer);
+                return 1;
+        }
 
+        drbd_start_resync(mdev, C_SYNC_SOURCE);
+        clear_bit(AHEAD_TO_SYNC_SOURCE, &mdev->current_epoch->flags);
         return 1;
 }