[Drbd-dev] [PATCH] drbd: fix a bug of got_peer_ack

[Rui Xu <rui.xu@easystack.cn>]

Consider a scenrio that io is ongoing and the backing disk of
secondary drbd suddenly broken. Some requset from primary node
will not be processed in receive_Data since there is no ldev.
And primary node will send peer_ack to secondary node for those
requsets, but the secondary node will not find these requests in
got_peer_ack.

The first problem caused by this bug is that the two nodes will be
disconnected, and the second problem is that some peer requests
can't be destroyed.

Fix it by find the last peer request on peer_requests list and then
the remaining requests on the list will be destroyed.

Signed-off-by: Rui Xu <rui.xu@easystack.cn>
---
 drbd/drbd_receiver.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drbd/drbd_receiver.c b/drbd/drbd_receiver.c
index 656d4eced..b63e83f52 100644
--- a/drbd/drbd_receiver.c
+++ b/drbd/drbd_receiver.c
@@ -9343,6 +9343,13 @@ static int got_peer_ack(struct drbd_connection *connection, struct packet_info *
 		if (dagtag == peer_req->dagtag_sector)
 			goto found;
 	}
+
+        list_for_each_entry(peer_req, &connection->peer_requests, recv_order) {
+                if (peer_req->dagtag_sector == atomic64_read(&connection->last_dagtag_sector)) {
+                        drbd_info(connection, "peer request with last dagtag sector %llu has found\n", peer_req->dagtag_sector);
+                        goto found;
+                }
+        }
 	spin_unlock_irq(&connection->peer_reqs_lock);
 
 	drbd_err(connection, "peer request with dagtag %llu not found\n", dagtag);
-- 
2.25.1