ctdb-client: Fix implementation of transaction start

Since g_lock checks if the process exists in case of conflicting lock,
there is no need to register srvid.

Transaction start returns a transaction handle and transaction
commit/cancel will free that handle.  Since we cannot call async code
in a talloc destructor, this avoids the use of talloc destructor for
cancelling the transaction.

If user frees the transaction handle instead of calling transaction
cancel, it will leave stale g_lock lock.  This stale g_lock lock  will
get cleaned up on next transaction attempt.

Signed-off-by: Amitay Isaacs <amitay@gmail.com>
Reviewed-by: Martin Schwenke <martin@meltin.net>

diff --git a/ctdb/client/client_db.c b/ctdb/client/client_db.c
index cb51b43f8d01a0a4a9955c4ef6543a1e84160474..e3b0ea1c187a5b7a9d5a1b1c55a8b62a84f910b7 100644 (file)
--- a/ctdb/client/client_db.c
+++ b/ctdb/client/client_db.c
@@ -1619,9 +1619,7 @@ struct ctdb_transaction_start_state {
 };
 
 static void ctdb_transaction_g_lock_attached(struct tevent_req *subreq);
-static void ctdb_transaction_register_done(struct tevent_req *subreq);
 static void ctdb_transaction_g_lock_done(struct tevent_req *subreq);
-static int ctdb_transaction_handle_destructor(struct ctdb_transaction_handle *h);
 
 struct tevent_req *ctdb_transaction_start_send(TALLOC_CTX *mem_ctx,
                                               struct tevent_context *ev,
@@ -1691,7 +1689,6 @@ static void ctdb_transaction_g_lock_attached(struct tevent_req *subreq)
                subreq, struct tevent_req);
        struct ctdb_transaction_start_state *state = tevent_req_data(
                req, struct ctdb_transaction_start_state);
-       struct ctdb_req_control request;
        bool status;
        int ret;
 
@@ -1702,42 +1699,9 @@ static void ctdb_transaction_g_lock_attached(struct tevent_req *subreq)
                return;
        }
 
-       ctdb_req_control_register_srvid(&request, state->h->sid.unique_id);
-       subreq = ctdb_client_control_send(state, state->ev, state->client,
-                                         state->destnode, state->timeout,
-                                         &request);
-       if (tevent_req_nomem(subreq, req)) {
-               return;
-       }
-       tevent_req_set_callback(subreq, ctdb_transaction_register_done, req);
-}
-
-static void ctdb_transaction_register_done(struct tevent_req *subreq)
-{
-       struct tevent_req *req = tevent_req_callback_data(
-               subreq, struct tevent_req);
-       struct ctdb_transaction_start_state *state = tevent_req_data(
-               req, struct ctdb_transaction_start_state);
-       struct ctdb_reply_control *reply;
-       bool status;
-       int ret;
-
-       status = ctdb_client_control_recv(subreq, &ret, state, &reply);
-       TALLOC_FREE(subreq);
-       if (! status) {
-               tevent_req_error(req, ret);
-               return;
-       }
-
-       ret = ctdb_reply_control_register_srvid(reply);
-       talloc_free(reply);
-       if (ret != 0) {
-               tevent_req_error(req, ret);
-               return;
-       }
-
        subreq = ctdb_g_lock_lock_send(state, state->ev, state->client,
-                                      state->h->db_g_lock, state->h->lock_name,
+                                      state->h->db_g_lock,
+                                      state->h->lock_name,
                                       &state->h->sid, state->h->readonly);
        if (tevent_req_nomem(subreq, req)) {
                return;
@@ -1778,24 +1742,9 @@ struct ctdb_transaction_handle *ctdb_transaction_start_recv(
                return NULL;
        }
 
-       talloc_set_destructor(h, ctdb_transaction_handle_destructor);
        return h;
 }
 
-static int ctdb_transaction_handle_destructor(struct ctdb_transaction_handle *h)
-{
-       int ret;
-
-       ret = ctdb_ctrl_deregister_srvid(h, h->ev, h->client, h->client->pnn,
-                                        tevent_timeval_zero(),
-                                        h->sid.unique_id);
-       if (ret != 0) {
-               DEBUG(DEBUG_WARNING, ("Failed to deregister SRVID\n"));
-       }
-
-       return 0;
-}
-
 int ctdb_transaction_start(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
                           struct ctdb_client_context *client,
                           struct timeval timeout,