libceph: fix messenger retry

In ancient times, the messenger could both initiate and accept connections.
An artifact if that was data structures to store/process an incoming
ceph_msg_connect request and send an outgoing ceph_msg_connect_reply.
Sadly, the negotiation code was referencing those structures and ignoring
important information (like the peer's connect_seq) from the correct ones.

Among other things, this fixes tight reconnect loops where the server sends
RETRY_SESSION and we (the client) retries with the same connect_seq as last
time.  This bug pretty easily triggered by injecting socket failures on the
MDS and running some fs workload like workunits/direct_io/test_sync_io.

Signed-off-by: Sage Weil <sage@inktank.com>

1 files changed, 2 insertions, 10 deletions

diff --git a/include/linux/ceph/messenger.h b/include/linux/ceph/messenger.h
index 478f814f210..cfb1bbdac62 100644
--- a/include/linux/ceph/messenger.h
+++ b/include/linux/ceph/messenger.h
@@ -172,16 +172,8 @@ struct ceph_connection {
 
         /* connection negotiation temps */
         char in_banner[CEPH_BANNER_MAX_LEN];
-        union {
-                struct {  /* outgoing connection */
-                        struct ceph_msg_connect out_connect;
-                        struct ceph_msg_connect_reply in_reply;
-                };
-                struct {  /* incoming */
-                        struct ceph_msg_connect in_connect;
-                        struct ceph_msg_connect_reply out_reply;
-                };
-        };
+        struct ceph_msg_connect out_connect;
+        struct ceph_msg_connect_reply in_reply;
         struct ceph_entity_addr actual_peer_addr;
 
         /* message out temps */