[Tarantool-patches] [PATCH v2 4/4] qsync: don't send negative timeouts into fiber_cond_wait_timeout

[Cyrill Gorcunov <gorcunov@gmail.com>]

Basically our timeout is calculated via (a - b), where
@a is a constant positive value fetched once, in turn
the @b is rather a dynamic value thus the result may
be negative. libev uses assert() call to catch such
values when passed to timers setup. Thus lets intercept
potential assert() trigger and exit early if timeout
is already expired.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
---
There were a typo, so I force-updated the branch

 src/box/txn_limbo.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/box/txn_limbo.c b/src/box/txn_limbo.c
index d5b887d36..0924952b7 100644
--- a/src/box/txn_limbo.c
+++ b/src/box/txn_limbo.c
@@ -174,8 +174,10 @@ txn_limbo_wait_complete(struct txn_limbo *limbo, struct txn_limbo_entry *entry)
 	double start_time = fiber_clock();
 	while (true) {
 		double deadline = start_time + replication_synchro_timeout;
-		bool cancellable = fiber_set_cancellable(false);
 		double timeout = deadline - fiber_clock();
+		if (timeout < 0)
+			goto do_rollback;
+		bool cancellable = fiber_set_cancellable(false);
 		int rc = fiber_cond_wait_timeout(&limbo->wait_cond, timeout);
 		fiber_set_cancellable(cancellable);
 		if (txn_limbo_entry_is_complete(entry))
@@ -509,8 +511,10 @@ txn_limbo_wait_confirm(struct txn_limbo *limbo)
 	double start_time = fiber_clock();
 	while (true) {
 		double deadline = start_time + replication_synchro_timeout;
-		bool cancellable = fiber_set_cancellable(false);
 		double timeout = deadline - fiber_clock();
+		if (timeout < 0)
+			goto timed_out;
+		bool cancellable = fiber_set_cancellable(false);
 		int rc = fiber_cond_wait_timeout(&limbo->wait_cond, timeout);
 		fiber_set_cancellable(cancellable);
 		if (cwp.is_confirm || cwp.is_rollback)
-- 
2.26.2