[tarantool-patches] [PATCH 05/10] Get rid of fiber_gc from txn_rollback

[Georgy Kirichenko <georgy@tarantool.org>]

Don't touch a fiber gc storage on a transaction rollback. This relaxes
dependencies between fiber and transaction life cycles.

Prerequisites: #1254
---
 src/box/applier.cc     |  9 ++++++---
 src/box/box.cc         | 24 +++++++++++++++++-------
 src/box/call.c         | 16 ++++++++++++----
 src/box/memtx_engine.c |  3 ++-
 src/box/txn.c          | 22 +++++++++++-----------
 src/box/txn.h          |  7 +++++--
 src/box/vy_scheduler.c |  6 ++++--
 7 files changed, 57 insertions(+), 30 deletions(-)

diff --git a/src/box/applier.cc b/src/box/applier.cc
index 3b74e0f54..42b6efc4d 100644
--- a/src/box/applier.cc
+++ b/src/box/applier.cc
@@ -182,7 +182,8 @@ apply_initial_join_row(struct xrow_header *row)
 		return -1;
 	/* no access checks here - applier always works with admin privs */
 	if (space_apply_initial_join_row(space, &request)) {
-		txn_rollback();
+		txn_rollback(txn);
+		fiber_gc();
 		return -1;
 	}
 	int rc = txn_commit(txn);
@@ -418,7 +419,8 @@ applier_join(struct applier *applier)
 			if (txn == NULL)
 				diag_raise();
 			if (apply_row(&row) != 0) {
-				txn_rollback();
+				txn_rollback(txn);
+				fiber_gc();
 				diag_raise();
 			}
 			if (txn_commit(txn) != 0)
@@ -621,7 +623,8 @@ applier_apply_tx(struct stailq *rows)
 	return txn_commit(txn);
 
 rollback:
-	txn_rollback();
+	txn_rollback(txn);
+	fiber_gc();
 	return -1;
 }
 
diff --git a/src/box/box.cc b/src/box/box.cc
index 54210474f..835a00c95 100644
--- a/src/box/box.cc
+++ b/src/box/box.cc
@@ -197,9 +197,12 @@ box_process_rw(struct request *request, struct space *space,
 
 	if (txn_commit_stmt(txn, request) != 0)
 		goto fail;
+
 	if (autocommit) {
-		if (txn_commit(txn) != 0)
+		if (txn_commit(txn) != 0) {
+			txn = NULL;
 			goto fail;
+		}
 		fiber_gc();
 	}
 
@@ -212,8 +215,11 @@ box_process_rw(struct request *request, struct space *space,
 	return 0;
 
 fail:
-	if (autocommit)
-		txn_rollback();
+	if (autocommit) {
+		if (txn != NULL)
+			txn_rollback(txn);
+		fiber_gc();
+	}
 	if (tuple != NULL)
 		tuple_unref(tuple);
 	return -1;
@@ -323,8 +329,10 @@ apply_wal_row(struct xstream *stream, struct xrow_header *row)
 		if (txn == NULL || box_process_rw(&request, space, NULL) != 0 ||
 		    txn_commit(txn) != 0) {
 			say_error("error applying row: %s", request_str(&request));
-			if (txn != NULL)
-				txn_rollback();
+			if (txn != NULL) {
+				txn_rollback(txn);
+				fiber_gc();
+			}
 			diag_raise();
 		}
 	}
@@ -1342,7 +1350,8 @@ box_register_replica(uint32_t id, const struct tt_uuid *uuid)
 		diag_raise();
 	if (boxk(IPROTO_INSERT, BOX_CLUSTER_ID, "[%u%s]",
 		 (unsigned) id, tt_uuid_str(uuid)) != 0) {
-		txn_rollback();
+		txn_rollback(txn);
+		fiber_gc();
 		diag_raise();
 	}
 	if (txn_commit(txn) != 0)
@@ -1673,7 +1682,8 @@ box_set_replicaset_uuid(const struct tt_uuid *replicaset_uuid)
 	/* Save replica set UUID in _schema */
 	if (boxk(IPROTO_INSERT, BOX_SCHEMA_ID, "[%s%s]", "cluster",
 		 tt_uuid_str(&uu))) {
-		txn_rollback();
+		txn_rollback(txn);
+		fiber_gc();
 		diag_raise();
 	}
 	if (txn_commit(txn) != 0)
diff --git a/src/box/call.c b/src/box/call.c
index b9750c5f3..4b5f155df 100644
--- a/src/box/call.c
+++ b/src/box/call.c
@@ -208,13 +208,17 @@ box_process_call(struct call_request *request, struct port *port)
 		fiber_set_user(fiber(), orig_credentials);
 
 	if (rc != 0) {
-		txn_rollback();
+		if (in_txn() != NULL)
+			txn_rollback(in_txn());
+		fiber_gc();
 		return -1;
 	}
 
 	if (in_txn()) {
 		diag_set(ClientError, ER_FUNCTION_TX_ACTIVE);
-		txn_rollback();
+		if (in_txn() != NULL)
+			txn_rollback(in_txn());
+		fiber_gc();
 		return -1;
 	}
 
@@ -229,13 +233,17 @@ box_process_eval(struct call_request *request, struct port *port)
 	if (access_check_universe(PRIV_X) != 0)
 		return -1;
 	if (box_lua_eval(request, port) != 0) {
-		txn_rollback();
+		if (in_txn() != NULL)
+			txn_rollback(in_txn());
+		fiber_gc();
 		return -1;
 	}
 
 	if (in_txn()) {
 		diag_set(ClientError, ER_FUNCTION_TX_ACTIVE);
-		txn_rollback();
+		if (in_txn() != NULL)
+			txn_rollback(in_txn());
+		fiber_gc();
 		return -1;
 	}
 
diff --git a/src/box/memtx_engine.c b/src/box/memtx_engine.c
index afa1739c6..cf2205c68 100644
--- a/src/box/memtx_engine.c
+++ b/src/box/memtx_engine.c
@@ -277,7 +277,8 @@ memtx_engine_recover_snapshot_row(struct memtx_engine *memtx,
 		return -1;
 	/* no access checks here - applier always works with admin privs */
 	if (space_apply_initial_join_row(space, &request) != 0) {
-		txn_rollback();
+		txn_rollback(txn);
+		fiber_gc();
 		return -1;
 	}
 	int rc = txn_commit(txn);
diff --git a/src/box/txn.c b/src/box/txn.c
index 804962767..fdfffa144 100644
--- a/src/box/txn.c
+++ b/src/box/txn.c
@@ -347,7 +347,7 @@ txn_write_to_wal(struct txn *txn)
 
 	if (res < 0) {
 		/* Cascading rollback. */
-		txn_rollback(); /* Perform our part of cascading rollback. */
+		txn_rollback(txn); /* Perform our part of cascading rollback. */
 		/*
 		 * Move fiber to end of event loop to avoid
 		 * execution of any new requests before all
@@ -396,7 +396,7 @@ txn_commit(struct txn *txn)
 	if (txn->n_new_rows + txn->n_applier_rows > 0) {
 		txn->signature = txn_write_to_wal(txn);
 		if (txn->signature < 0)
-			goto fail;
+			return -1;
 	}
 	/*
 	 * The transaction is in the binary log. No action below
@@ -424,7 +424,7 @@ txn_commit(struct txn *txn)
 	txn_free(txn);
 	return 0;
 fail:
-	txn_rollback();
+	txn_rollback(txn);
 	return -1;
 }
 
@@ -439,11 +439,9 @@ txn_rollback_stmt()
 }
 
 void
-txn_rollback()
+txn_rollback(struct txn *txn)
 {
-	struct txn *txn = in_txn();
-	if (txn == NULL)
-		return;
+	assert(txn == in_txn());
 	/* Rollback triggers must not throw. */
 	if (txn->has_triggers &&
 	    trigger_run(&txn->on_rollback, txn) != 0) {
@@ -458,8 +456,6 @@ txn_rollback()
 	stailq_foreach_entry(stmt, &txn->stmts, next)
 		txn_stmt_unref_tuples(stmt);
 
-	/** Free volatile txn memory. */
-	fiber_gc();
 	fiber_set_txn(fiber(), NULL);
 	txn_free(txn);
 }
@@ -535,11 +531,14 @@ int
 box_txn_rollback()
 {
 	struct txn *txn = in_txn();
+	if (txn == NULL)
+		return 0;
 	if (txn && txn->in_sub_stmt) {
 		diag_set(ClientError, ER_ROLLBACK_IN_SUB_STMT);
 		return -1;
 	}
-	txn_rollback(); /* doesn't throw */
+	txn_rollback(txn); /* doesn't throw */
+	fiber_gc();
 	return 0;
 }
 
@@ -617,6 +616,7 @@ txn_on_stop(struct trigger *trigger, void *event)
 {
 	(void) trigger;
 	(void) event;
-	txn_rollback();                 /* doesn't yield or fail */
+	txn_rollback(in_txn());                 /* doesn't yield or fail */
+
 }
 
diff --git a/src/box/txn.h b/src/box/txn.h
index 7f999b8e9..ae2d7b9a5 100644
--- a/src/box/txn.h
+++ b/src/box/txn.h
@@ -213,9 +213,12 @@ txn_begin();
 int
 txn_commit(struct txn *txn);
 
-/** Rollback a transaction, if any. */
+/**
+ * Rollback a transaction.
+ * @pre txn == in_txn()
+ */
 void
-txn_rollback();
+txn_rollback(struct txn *txn);
 
 /**
  * Roll back the transaction but keep the object around.
diff --git a/src/box/vy_scheduler.c b/src/box/vy_scheduler.c
index fabb4bb48..1f6b30f4a 100644
--- a/src/box/vy_scheduler.c
+++ b/src/box/vy_scheduler.c
@@ -889,8 +889,10 @@ vy_deferred_delete_batch_process_f(struct cmsg *cmsg)
 	for (int i = 0; i < batch->count; i++) {
 		if (vy_deferred_delete_process_one(deferred_delete_space,
 						   pk->space_id, pk->mem_format,
-						   &batch->stmt[i]) != 0)
+						   &batch->stmt[i]) != 0) {
+			txn_rollback(txn);
 			goto fail;
+		}
 	}
 
 	if (txn_commit(txn) != 0)
@@ -900,7 +902,7 @@ vy_deferred_delete_batch_process_f(struct cmsg *cmsg)
 fail:
 	batch->is_failed = true;
 	diag_move(diag_get(), &batch->diag);
-	txn_rollback();
+	fiber_gc();
 }
 
 /**
-- 
2.21.0