SERVER-69756: Abort a resharding operation immediately.

(cherry picked from commit befe8bb9cf767db458149afca838823d2fd4876c)

3 files changed, 44 insertions, 2 deletions

diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
index ccfcbd8cb24..6241ef98254 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.cpp
@@ -94,6 +94,7 @@ MONGO_FAIL_POINT_DEFINE(reshardingPauseCoordinatorBeforeStartingErrorFlow);
 MONGO_FAIL_POINT_DEFINE(reshardingPauseCoordinatorBeforePersistingStateTransition);
 MONGO_FAIL_POINT_DEFINE(pauseBeforeTellDonorToRefresh);
 MONGO_FAIL_POINT_DEFINE(pauseBeforeInsertCoordinatorDoc);
+MONGO_FAIL_POINT_DEFINE(pauseBeforeCTHolderInitialization);
 
 const std::string kReshardingCoordinatorActiveIndexName = "ReshardingCoordinatorActiveIndex";
 const Backoff kExponentialBackoff(Seconds(1), Milliseconds::max());
@@ -1298,7 +1299,18 @@ ReshardingCoordinatorService::ReshardingCoordinator::_commitAndFinishReshardOper
 SemiFuture<void> ReshardingCoordinatorService::ReshardingCoordinator::run(
     std::shared_ptr<executor::ScopedTaskExecutor> executor,
     const CancellationToken& stepdownToken) noexcept {
-    _ctHolder = std::make_unique<CoordinatorCancellationTokenHolder>(stepdownToken);
+    pauseBeforeCTHolderInitialization.pauseWhileSet();
+
+    auto abortCalled = [&] {
+        stdx::lock_guard<Latch> lk(_abortCalledMutex);
+        _ctHolder = std::make_unique<CoordinatorCancellationTokenHolder>(stepdownToken);
+        return _abortCalled;
+    }();
+
+    if (abortCalled) {
+        _ctHolder->abort();
+    }
+
     _markKilledExecutor->startup();
     _cancelableOpCtxFactory.emplace(_ctHolder->getAbortToken(), _markKilledExecutor);
 
@@ -1454,7 +1466,15 @@ ReshardingCoordinatorService::ReshardingCoordinator::_onAbortCoordinatorAndParti
 }
 
 void ReshardingCoordinatorService::ReshardingCoordinator::abort() {
-    _ctHolder->abort();
+    auto ctHolderInitialized = [&] {
+        stdx::lock_guard<Latch> lk(_abortCalledMutex);
+        _abortCalled = true;
+        return !(_ctHolder == nullptr);
+    }();
+
+    if (ctHolderInitialized) {
+        _ctHolder->abort();
+    }
 }
 
 boost::optional<BSONObj> ReshardingCoordinatorService::ReshardingCoordinator::reportForCurrentOp(
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service.h b/src/mongo/db/s/resharding/resharding_coordinator_service.h
index 9759078eda1..6a012407b25 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service.h
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service.h
@@ -536,6 +536,13 @@ private:
         MONGO_MAKE_LATCH("ReshardingCoordinatorService::_fulfillmentMutex");
 
     /**
+     * Must be locked while the _abortCalled is being set to true.
+     */
+    mutable Mutex _abortCalledMutex =
+        MONGO_MAKE_LATCH("ReshardingCoordinatorService::_abortCalledMutex");
+
+
+    /**
      * Coordinator does not enter the critical section until this is fulfilled.
      * Can be set by "commitReshardCollection" command or by metrics determining
      * that it's okay to proceed.
@@ -555,6 +562,10 @@ private:
     std::shared_ptr<resharding::CoordinatorCommitMonitor> _commitMonitor;
 
     std::shared_ptr<ReshardingCoordinatorExternalState> _reshardingCoordinatorExternalState;
+
+    // Used to catch the case when an abort() is called but the cancellation source (_ctHolder) has
+    // not been initialized.
+    bool _abortCalled{false};
 };
 
 }  // namespace mongo
diff --git a/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp b/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
index 6a5197b4c41..188fc400e29 100644
--- a/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
+++ b/src/mongo/db/s/resharding/resharding_coordinator_service_test.cpp
@@ -923,5 +923,16 @@ TEST_F(ReshardingCoordinatorServiceTest, ReshardingCoordinatorFailsIfMigrationNo
     }
 }
 
+TEST_F(ReshardingCoordinatorServiceTest, SuccessfullyAbortReshardOperationImmediately) {
+    auto pauseBeforeCTHolderInitialization =
+        globalFailPointRegistry().find("pauseBeforeCTHolderInitialization");
+    auto timesEnteredFailPoint = pauseBeforeCTHolderInitialization->setMode(FailPoint::alwaysOn, 0);
+    auto coordinator = initializeAndGetCoordinator();
+    coordinator->abort();
+    pauseBeforeCTHolderInitialization->waitForTimesEntered(timesEnteredFailPoint + 1);
+    pauseBeforeCTHolderInitialization->setMode(FailPoint::off, 0);
+    coordinator->getCompletionFuture().wait();
+}
+
 }  // namespace
 }  // namespace mongo