SERVER-64304 Prevent a server crash due to index builds started when using the --recoverFromOplogAsStandalone startup parameter

6 files changed, 21 insertions, 6 deletions

diff --git a/src/mongo/db/active_index_builds.cpp b/src/mongo/db/active_index_builds.cpp
index 9edde200e35..017ca49ecc8 100644
--- a/src/mongo/db/active_index_builds.cpp
+++ b/src/mongo/db/active_index_builds.cpp
@@ -201,7 +201,7 @@ Status ActiveIndexBuilds::registerIndexBuild(
     return Status::OK();
 }
 
-size_t ActiveIndexBuilds::getActiveIndexBuilds() {
+size_t ActiveIndexBuilds::getActiveIndexBuilds() const {
     stdx::unique_lock<Latch> lk(_mutex);
     return _allIndexBuilds.size();
 }
diff --git a/src/mongo/db/active_index_builds.h b/src/mongo/db/active_index_builds.h
index 47a276e9ec9..ec4f07f26cf 100644
--- a/src/mongo/db/active_index_builds.h
+++ b/src/mongo/db/active_index_builds.h
@@ -98,7 +98,7 @@ public:
     /**
      * Get the number of in-progress index builds.
      */
-    size_t getActiveIndexBuilds();
+    size_t getActiveIndexBuilds() const;
 
     /**
      * When _sleepForTest is true, this function will sleep for 100ms and then check the value
diff --git a/src/mongo/db/index_builds_coordinator.cpp b/src/mongo/db/index_builds_coordinator.cpp
index 9bd1677a4d6..192b8371d84 100644
--- a/src/mongo/db/index_builds_coordinator.cpp
+++ b/src/mongo/db/index_builds_coordinator.cpp
@@ -1509,6 +1509,10 @@ void IndexBuildsCoordinator::restartIndexBuildsForRecovery(
     }
 }
 
+bool IndexBuildsCoordinator::noIndexBuildInProgress() const {
+    return activeIndexBuilds.getActiveIndexBuilds() == 0;
+}
+
 int IndexBuildsCoordinator::numInProgForDb(StringData db) const {
     auto indexBuildFilter = [db](const auto& replState) { return db == replState.dbName; };
     auto dbIndexBuilds = activeIndexBuilds.filterIndexBuilds(indexBuildFilter);
diff --git a/src/mongo/db/index_builds_coordinator.h b/src/mongo/db/index_builds_coordinator.h
index 9e4325aecb5..0ae137f047b 100644
--- a/src/mongo/db/index_builds_coordinator.h
+++ b/src/mongo/db/index_builds_coordinator.h
@@ -342,6 +342,11 @@ public:
                                    const CommitQuorumOptions& newCommitQuorum) = 0;
 
     /**
+     * Returns true if there are no index builds in progress.
+     */
+    bool noIndexBuildInProgress() const;
+
+    /**
      * Returns the number of index builds that are running on the specified database.
      */
     int numInProgForDb(StringData db) const;
diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 7d82b153607..499f5de261a 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -298,6 +298,7 @@ env.Library(
     ],
     LIBDEPS_PRIVATE=[
         '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/db/index_builds_coordinator_interface',
         '$BUILD_DIR/mongo/db/storage/journal_flusher',
         '$BUILD_DIR/mongo/db/storage/storage_control',
         '$BUILD_DIR/mongo/db/storage/storage_options',
diff --git a/src/mongo/db/repl/replication_recovery.cpp b/src/mongo/db/repl/replication_recovery.cpp
index 0eff812175e..7d940aaa58f 100644
--- a/src/mongo/db/repl/replication_recovery.cpp
+++ b/src/mongo/db/repl/replication_recovery.cpp
@@ -38,6 +38,7 @@
 #include "mongo/db/catalog/document_validation.h"
 #include "mongo/db/db_raii.h"
 #include "mongo/db/dbdirectclient.h"
+#include "mongo/db/index_builds_coordinator.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/repl/apply_ops.h"
@@ -363,11 +364,15 @@ void ReplicationRecoveryImpl::recoverFromOplogAsStandalone(OperationContext* opC
         // Initial sync will reconstruct prepared transactions when it is completely done.
         reconstructPreparedTransactions(opCtx, OplogApplication::Mode::kRecovering);
 
-        LOGV2_WARNING(21558,
-                      "Setting mongod to readOnly mode as a result of specifying "
-                      "'recoverFromOplogAsStandalone'");
+        // Two-phase index builds are built in the background, which may still be in-progress after
+        // recovering from the oplog. To prevent crashing the server, skip enabling read-only mode.
+        if (IndexBuildsCoordinator::get(opCtx)->noIndexBuildInProgress()) {
+            LOGV2_WARNING(21558,
+                          "Setting mongod to readOnly mode as a result of specifying "
+                          "'recoverFromOplogAsStandalone'");
 
-        storageGlobalParams.readOnly = true;
+            storageGlobalParams.readOnly = true;
+        }
     }
 }