kubernetes/staging/src/k8s.io/apiserver/pkg/endpoints/filters/storageversion.go

// WithStorageVersionPrecondition checks if the storage version barrier has
// completed, if not, it only passes the following API requests:
// 1. non-resource requests,
// 2. read requests,
// 3. write requests to the storageversion API,
// 4. create requests to the namespace API sent by apiserver itself,
// 5. write requests to the lease API in kube-system namespace,
// 6. resources whose StorageVersion is not pending update, including non-persisted resources.
func WithStorageVersionPrecondition(handler http.Handler, svm storageversion.Manager, s runtime.NegotiatedSerializer) http.Handler { … }

func contains(s []string, e string) bool { … }