rpc: destroy transport after client_t

Problem:
1. Ref counting increment on the client_t object is done in
   rpcsvc_request_init() which is incorrect.
2. Ref not taken when delegating to grace_time_handler()

Solution:
1. Only fop requests which require processing down the graph via
   stack 'frames' now ref count the request in get_frame_from_request()
2. Take ref on client_t object in server_rpc_notify() but avoid
   dropping in RPCSVC_EVENT_TRANSPORT_DESRTROY. Drop the ref
   unconditionally when exiting out of grace_time_handler().
   Also, avoid dropping ref on client_t in
   RPCSVC_EVENT_TRANSPORT_DESTROY when ref mangement as been
   delegated to grace_time_handler()

mainline:
> BUG: 1481600
> Reported-by: Raghavendra G <rgowdapp@redhat.com>
> Signed-off-by: Milind Changire <mchangir@redhat.com>
> Reviewed-on: https://review.gluster.org/17982
> Tested-by: Raghavendra G <rgowdapp@redhat.com>
> Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
> CentOS-regression: Gluster Build System <jenkins@build.gluster.org>
> Smoke: Gluster Build System <jenkins@build.gluster.org>
(cherry picked from commit 24b95089a18a6a40e7703cb344e92025d67f3086)

Change-Id: Ic16246bebc7ea4490545b26564658f4b081675e4
BUG: 1487033
Reported-by: Raghavendra G <rgowdapp@redhat.com>
Signed-off-by: Milind Changire <mchangir@redhat.com>
Reviewed-on: https://review.gluster.org/18156
Smoke: Gluster Build System <jenkins@build.gluster.org>
Reviewed-by: Raghavendra G <rgowdapp@redhat.com>
Tested-by: Raghavendra G <rgowdapp@redhat.com>
CentOS-regression: Gluster Build System <jenkins@build.gluster.org>

1 files changed, 16 insertions, 1 deletions

diff --git a/xlators/protocol/server/src/server-handshake.c b/xlators/protocol/server/src/server-handshake.c
index fa2f61315df..731e1c184ef 100644
--- a/xlators/protocol/server/src/server-handshake.c
+++ b/xlators/protocol/server/src/server-handshake.c
@@ -633,9 +633,24 @@ server_setvolume (rpcsvc_request_t *req)
 
         gf_msg_debug (this->name, 0, "Connected to %s", client->client_uid);
         cancelled = server_cancel_grace_timer (this, client);
-        if (cancelled)//Do gf_client_put on behalf of grace-timer-handler.
+        if (cancelled) {
+                /* If timer has been successfully cancelled then it means
+                 * that the client has reconnected within grace period.
+                 * Since we've bumped up the bind count with a gf_client_get()
+                 * for this connect attempt, we need to drop the bind count
+                 * for earlier connect, since grace timer handler couldn't
+                 * drop it since the timer was cancelled.
+                 */
                 gf_client_put (client, NULL);
 
+                /* We need to drop the ref count for this reconnected client
+                 * since one ref was taken before delegating to the grace
+                 * timer handler. Since grace timer handler was cancelled,
+                 * it couldn't run and drop the ref either.
+                 */
+                gf_client_unref (client);
+        }
+
         serv_ctx = server_ctx_get (client, client->this);
         if (serv_ctx == NULL) {
                 gf_msg (this->name, GF_LOG_INFO, 0,