SERVER-28251 Fix race condition in index_killop.js

2 files changed, 13 insertions, 16 deletions

diff --git a/jstests/noPassthrough/index_killop.js b/jstests/noPassthrough/index_killop.js
index 9ea3034ad9e..4908ea5ded9 100644
--- a/jstests/noPassthrough/index_killop.js
+++ b/jstests/noPassthrough/index_killop.js
@@ -47,9 +47,6 @@
         // Kill the index build.
         assert.commandWorked(testDB.killOp(opId));
 
-        assert.commandWorked(
-            testDB.adminCommand({configureFailPoint: 'hangAfterStartingIndexBuild', mode: 'off'}));
-
         // Wait for the index build to stop.
         assert.soon(function() {
             return getIndexBuildOpId() == -1;
@@ -62,6 +59,9 @@
         // Check that no new index has been created.  This verifies that the index build was aborted
         // rather than successfully completed.
         assert.eq([{_id: 1}], testDB.test.getIndexKeys());
+
+        assert.commandWorked(
+            testDB.adminCommand({configureFailPoint: 'hangAfterStartingIndexBuild', mode: 'off'}));
     }
 
     testAbortIndexBuild({background: true});
diff --git a/src/mongo/db/catalog/index_create_impl.cpp b/src/mongo/db/catalog/index_create_impl.cpp
index 638b75765f5..598fe9fa581 100644
--- a/src/mongo/db/catalog/index_create_impl.cpp
+++ b/src/mongo/db/catalog/index_create_impl.cpp
@@ -320,11 +320,20 @@ Status MultiIndexBlockImpl::insertAllDocumentsInCollection(std::set<RecordId>* d
     PlanExecutor::ExecState state;
     int retries = 0;  // non-zero when retrying our last document.
     while (retries ||
-           (PlanExecutor::ADVANCED == (state = exec->getNextSnapshotted(&objToIndex, &loc)))) {
+           (PlanExecutor::ADVANCED == (state = exec->getNextSnapshotted(&objToIndex, &loc))) ||
+           MONGO_FAIL_POINT(hangAfterStartingIndexBuild)) {
         try {
             if (_allowInterruption)
                 _opCtx->checkForInterrupt();
 
+            if (!(retries || (PlanExecutor::ADVANCED == state))) {
+                // The only reason we are still in the loop is hangAfterStartingIndexBuild.
+                log() << "Hanging index build due to 'hangAfterStartingIndexBuild' failpoint";
+                invariant(_allowInterruption);
+                sleepmillis(1000);
+                continue;
+            }
+
             // Make sure we are working with the latest version of the document.
             if (objToIndex.snapshotId() != _opCtx->recoveryUnit()->getSnapshotId() &&
                 !_collection->findDoc(_opCtx, loc, &objToIndex)) {
@@ -383,18 +392,6 @@ Status MultiIndexBlockImpl::insertAllDocumentsInCollection(std::set<RecordId>* d
                 WorkingSetCommon::toStatusString(objToIndex.value()),
             state == PlanExecutor::IS_EOF);
 
-    if (MONGO_FAIL_POINT(hangAfterStartingIndexBuild)) {
-        // Need the index build to hang before the progress meter is marked as finished so we can
-        // reliably check that the index build has actually started in js tests.
-        while (MONGO_FAIL_POINT(hangAfterStartingIndexBuild)) {
-            log() << "Hanging index build due to 'hangAfterStartingIndexBuild' failpoint";
-            sleepmillis(1000);
-        }
-
-        // Check for interrupt to allow for killop prior to index build completion.
-        _opCtx->checkForInterrupt();
-    }
-
     if (MONGO_FAIL_POINT(hangAfterStartingIndexBuildUnlocked)) {
         // Unlock before hanging so replication recognizes we've completed.
         Locker::LockSnapshot lockInfo;