void IndexCatalogImpl::dropAllIndexes(OperationContext* opCtx,
                                      bool includingIdIndex,
                                      std::map<std::string, BSONObj>* droppedIndexes) {
    invariant(opCtx->lockState()->isCollectionLockedForMode(_collection->ns().toString(), MODE_X));

    BackgroundOperation::assertNoBgOpInProgForNs(_collection->ns().ns());

    // there may be pointers pointing at keys in the btree(s).  kill them.
    // TODO: can this can only clear cursors on this index?
    _collection->getCursorManager()->invalidateAll(
        opCtx, false, "all indexes on collection dropped");

    // make sure nothing in progress
    massert(17348,
            "cannot dropAllIndexes when index builds in progress",
            numIndexesTotal(opCtx) == numIndexesReady(opCtx));