ctdb-client: During transaction commit fetch seqnum locally

This avoids extra controls to the server.

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 3ceb019c4d69c342174802011b97a02f1d65810c..cb51b43f8d01a0a4a9955c4ef6543a1e84160474 100644 (file)
--- a/ctdb/client/client_db.c
+++ b/ctdb/client/client_db.c
@@ -1968,6 +1968,42 @@ int ctdb_transaction_delete_record(struct ctdb_transaction_handle *h,
        return ctdb_transaction_store_record(h, key, tdb_null);
 }
 
+static int ctdb_transaction_fetch_db_seqnum(struct ctdb_transaction_handle *h,
+                                           uint64_t *seqnum)
+{
+       const char *keyname = CTDB_DB_SEQNUM_KEY;
+       TDB_DATA key, data;
+       struct ctdb_ltdb_header header;
+       int ret;
+
+       key.dptr = discard_const(keyname);
+       key.dsize = strlen(keyname) + 1;
+
+       ret = ctdb_ltdb_fetch(h->db, key, &header, h, &data);
+       if (ret != 0) {
+               DEBUG(DEBUG_ERR,
+                     ("transaction_commit: %s seqnum fetch failed, ret=%d\n",
+                      h->db->db_name, ret));
+               return ret;
+       }
+
+       if (data.dsize == 0) {
+               /* initial data */
+               *seqnum = 0;
+               return 0;
+       }
+
+       if (data.dsize != sizeof(uint64_t)) {
+               talloc_free(data.dptr);
+               return EINVAL;
+       }
+
+       *seqnum = *(uint64_t *)data.dptr;
+
+       talloc_free(data.dptr);
+       return 0;
+}
+
 static int ctdb_transaction_store_db_seqnum(struct ctdb_transaction_handle *h,
                                            uint64_t seqnum)
 {
@@ -1989,10 +2025,8 @@ struct ctdb_transaction_commit_state {
        uint64_t seqnum;
 };
 
-static void ctdb_transaction_commit_seqnum_done(struct tevent_req *subreq);
 static void ctdb_transaction_commit_try(struct tevent_req *subreq);
 static void ctdb_transaction_commit_done(struct tevent_req *subreq);
-static void ctdb_transaction_commit_seqnum2_done(struct tevent_req *subreq);
 
 struct tevent_req *ctdb_transaction_commit_send(
                                        TALLOC_CTX *mem_ctx,
@@ -2001,7 +2035,7 @@ struct tevent_req *ctdb_transaction_commit_send(
 {
        struct tevent_req *req, *subreq;
        struct ctdb_transaction_commit_state *state;
-       struct ctdb_req_control request;
+       int ret;
 
        req = tevent_req_create(mem_ctx, &state,
                                struct ctdb_transaction_commit_state);
@@ -2012,53 +2046,25 @@ struct tevent_req *ctdb_transaction_commit_send(
        state->ev = ev;
        state->h = h;
 
-       ctdb_req_control_get_db_seqnum(&request, h->db->db_id);
-       subreq = ctdb_client_control_send(state, ev, h->client,
-                                         h->client->pnn,
-                                         tevent_timeval_zero(), &request);
-       if (tevent_req_nomem(subreq, req)) {
-               return tevent_req_post(req, ev);
-       }
-       tevent_req_set_callback(subreq, ctdb_transaction_commit_seqnum_done,
-                               req);
-
-       return req;
-}
-
-static void ctdb_transaction_commit_seqnum_done(struct tevent_req *subreq)
-{
-       struct tevent_req *req = tevent_req_callback_data(
-               subreq, struct tevent_req);
-       struct ctdb_transaction_commit_state *state = tevent_req_data(
-               req, struct ctdb_transaction_commit_state);
-       struct ctdb_reply_control *reply;
-       int ret;
-       bool status;
-
-       status = ctdb_client_control_recv(subreq, &ret, state, &reply);
-       TALLOC_FREE(subreq);
-       if (! status) {
-               tevent_req_error(req, ret);
-               return;
-       }
-
-       ret = ctdb_reply_control_get_db_seqnum(reply, &state->seqnum);
+       ret = ctdb_transaction_fetch_db_seqnum(h, &state->seqnum);
        if (ret != 0) {
                tevent_req_error(req, ret);
-               return;
+               return tevent_req_post(req, ev);
        }
 
-       ret = ctdb_transaction_store_db_seqnum(state->h, state->seqnum+1);
+       ret = ctdb_transaction_store_db_seqnum(h, state->seqnum+1);
        if (ret != 0) {
                tevent_req_error(req, ret);
-               return;
+               return tevent_req_post(req, ev);
        }
 
-       subreq = ctdb_recovery_wait_send(state, state->ev, state->h->client);
+       subreq = ctdb_recovery_wait_send(state, ev, h->client);
        if (tevent_req_nomem(subreq, req)) {
-               return;
+               return tevent_req_post(req, ev);
        }
        tevent_req_set_callback(subreq, ctdb_transaction_commit_try, req);
+
+       return req;
 }
 
 static void ctdb_transaction_commit_try(struct tevent_req *subreq)
@@ -2094,8 +2100,9 @@ static void ctdb_transaction_commit_done(struct tevent_req *subreq)
                subreq, struct tevent_req);
        struct ctdb_transaction_commit_state *state = tevent_req_data(
                req, struct ctdb_transaction_commit_state);
+       struct ctdb_transaction_handle *h = state->h;
        struct ctdb_reply_control *reply;
-       struct ctdb_req_control request;
+       uint64_t seqnum;
        int ret;
        bool status;
 
@@ -2109,8 +2116,7 @@ static void ctdb_transaction_commit_done(struct tevent_req *subreq)
        ret = ctdb_reply_control_trans3_commit(reply);
        if (ret < 0) {
                /* Control failed due to recovery */
-               subreq = ctdb_recovery_wait_send(state, state->ev,
-                                                state->h->client);
+               subreq = ctdb_recovery_wait_send(state, state->ev, h->client);
                if (tevent_req_nomem(subreq, req)) {
                        return;
                }
@@ -2119,44 +2125,15 @@ static void ctdb_transaction_commit_done(struct tevent_req *subreq)
                return;
        }
 
-       ctdb_req_control_get_db_seqnum(&request, state->h->db->db_id);
-       subreq = ctdb_client_control_send(state, state->ev, state->h->client,
-                                         state->h->client->pnn,
-                                         tevent_timeval_zero(), &request);
-       if (tevent_req_nomem(subreq, req)) {
-               return;
-       }
-       tevent_req_set_callback(subreq, ctdb_transaction_commit_seqnum2_done,
-                               req);
-}
-
-static void ctdb_transaction_commit_seqnum2_done(struct tevent_req *subreq)
-{
-       struct tevent_req *req = tevent_req_callback_data(
-               subreq, struct tevent_req);
-       struct ctdb_transaction_commit_state *state = tevent_req_data(
-               req, struct ctdb_transaction_commit_state);
-       struct ctdb_reply_control *reply;
-       uint64_t seqnum;
-       int ret;
-       bool status;
-
-       status = ctdb_client_control_recv(subreq, &ret, state, &reply);
-       TALLOC_FREE(subreq);
-       if (! status) {
-               tevent_req_error(req, ret);
-               return;
-       }
-
-       ret = ctdb_reply_control_get_db_seqnum(reply, &seqnum);
+       ret = ctdb_transaction_fetch_db_seqnum(h, &seqnum);
        if (ret != 0) {
                tevent_req_error(req, ret);
                return;
        }
 
        if (seqnum == state->seqnum) {
-               subreq = ctdb_recovery_wait_send(state, state->ev,
-                                                state->h->client);
+               /* try again */
+               subreq = ctdb_recovery_wait_send(state, state->ev, h->client);
                if (tevent_req_nomem(subreq, req)) {
                        return;
                }