[PATCH v2 04/11] vinyl: move transaction size sanity check to quota

[Vladimir Davydov]

There's a sanity check in vinyl_engine_prepare, which checks if the
transaction size is less than the configured limit and fails without
waiting for quota if it isn't. Let's move this check to vy_quota_use,
because it's really a business of the quota object. This implies that
vy_quota_use has to set diag to differentiate this error from timeout.
---
 src/box/vinyl.c    | 14 +-------------
 src/box/vy_quota.c | 18 ++++++++++++++++--
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/box/vinyl.c b/src/box/vinyl.c
index 1c0192cb..4ca2953b 100644
--- a/src/box/vinyl.c
+++ b/src/box/vinyl.c
@@ -2331,16 +2331,6 @@ vinyl_engine_prepare(struct engine *engine, struct txn *txn)
 		return -1;
 
 	/*
-	 * The configured memory limit will never allow us to commit
-	 * this transaction. Fail early.
-	 */
-	if (tx->write_size > env->quota.limit) {
-		diag_set(OutOfMemory, tx->write_size,
-			 "lsregion", "vinyl transaction");
-		return -1;
-	}
-
-	/*
 	 * Do not abort join/subscribe on quota timeout - replication
 	 * is asynchronous anyway and there's box.info.replication
 	 * available for the admin to track the lag so let the applier
@@ -2354,10 +2344,8 @@ vinyl_engine_prepare(struct engine *engine, struct txn *txn)
 	 * the transaction to be sent to read view or aborted, we call
 	 * it before checking for conflicts.
 	 */
-	if (vy_quota_use(&env->quota, tx->write_size, timeout) != 0) {
-		diag_set(ClientError, ER_VY_QUOTA_TIMEOUT);
+	if (vy_quota_use(&env->quota, tx->write_size, timeout) != 0)
 		return -1;
-	}
 
 	size_t mem_used_before = lsregion_used(&env->mem_env.allocator);
 
diff --git a/src/box/vy_quota.c b/src/box/vy_quota.c
index 64ce56c0..2afed6b7 100644
--- a/src/box/vy_quota.c
+++ b/src/box/vy_quota.c
@@ -35,6 +35,9 @@
 #include <stddef.h>
 #include <tarantool_ev.h>
 
+#include "diag.h"
+#include "error.h"
+#include "errcode.h"
 #include "fiber.h"
 #include "fiber_cond.h"
 #include "say.h"
@@ -139,6 +142,15 @@ vy_quota_use(struct vy_quota *q, size_t size, double timeout)
 		return 0;
 	}
 
+	/*
+	 * Fail early if the configured memory limit never allows
+	 * us to commit the transaction.
+	 */
+	if (size > q->limit) {
+		diag_set(OutOfMemory, size, "lsregion", "vinyl transaction");
+		return -1;
+	}
+
 	/* Wait for quota. */
 	double wait_start = ev_monotonic_now(loop());
 	double deadline = wait_start + timeout;
@@ -152,8 +164,10 @@ vy_quota_use(struct vy_quota *q, size_t size, double timeout)
 		 */
 		if (q->used + size > q->limit)
 			q->quota_exceeded_cb(q);
-		if (fiber_cond_wait_deadline(&q->cond, deadline) != 0)
-			return -1; /* timed out */
+		if (fiber_cond_wait_deadline(&q->cond, deadline) != 0) {
+			diag_set(ClientError, ER_VY_QUOTA_TIMEOUT);
+			return -1;
+		}
 	} while (!vy_quota_may_use(q, size));
 
 	double wait_time = ev_monotonic_now(loop()) - wait_start;
-- 
2.11.0