SERVER-65116 Abort active index builds when write blocking is enabled

1 files changed, 19 insertions, 0 deletions

diff --git a/src/mongo/db/commands/set_user_write_block_mode_command.cpp b/src/mongo/db/commands/set_user_write_block_mode_command.cpp
index b1d645dda4b..f4f6cb1d61f 100644
--- a/src/mongo/db/commands/set_user_write_block_mode_command.cpp
+++ b/src/mongo/db/commands/set_user_write_block_mode_command.cpp
@@ -35,8 +35,10 @@
 #include "mongo/db/commands.h"
 #include "mongo/db/commands/feature_compatibility_version.h"
 #include "mongo/db/commands/set_user_write_block_mode_gen.h"
+#include "mongo/db/index_builds_coordinator.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/repl/replication_coordinator.h"
+#include "mongo/db/s/global_user_write_block_state.h"
 #include "mongo/db/s/user_writes_recoverable_critical_section_service.h"
 #include "mongo/db/server_feature_flags_gen.h"
 #include "mongo/logv2/log.h"
@@ -74,6 +76,9 @@ public:
                     repl::ReplicationCoordinator::get(opCtx)->getReplicationMode() !=
                         repl::ReplicationCoordinator::modeNone);
 
+            // Only one attempt to change write block mode may make progress at once, because the
+            // way we enable/disable user index build blocking is not concurrency-safe.
+            stdx::lock_guard lock(_mutex);
             {
                 // TODO SERVER-65010 Remove FCV guard once 6.0 has branched out
                 FixedFCVRegion fixedFcvRegion(opCtx);
@@ -83,6 +88,18 @@ public:
                             serverGlobalParams.featureCompatibility));
 
                 if (request().getGlobal()) {
+                    // Enabling write block mode on a replicaset requires several steps
+                    // First, we must prevent new index builds from starting
+                    auto writeBlockState = GlobalUserWriteBlockState::get(opCtx);
+                    writeBlockState->enableUserIndexBuildBlocking(opCtx);
+                    // Ensure that we eventually restore index build state.
+                    ScopeGuard guard(
+                        [&]() { writeBlockState->disableUserIndexBuildBlocking(opCtx); });
+                    // Abort and wait for ongoing index builds to finish.
+                    IndexBuildsCoordinator::get(opCtx)->abortUserIndexBuildsForUserWriteBlocking(
+                        opCtx);
+
+                    // Engage write blocking
                     UserWritesRecoverableCriticalSectionService::get(opCtx)
                         ->acquireRecoverableCriticalSectionBlockingUserWrites(
                             opCtx,
@@ -122,6 +139,8 @@ public:
                         ->isAuthorizedForPrivilege(Privilege{ResourcePattern::forClusterResource(),
                                                              ActionType::setUserWriteBlockMode}));
         }
+
+        Mutex _mutex = MONGO_MAKE_LATCH("SetUserWriteBlockModeCommand::_mutex");
     };
 } setUserWriteBlockModeCommand;
 }  // namespace