diff --git a/vendor/go.etcd.io/etcd/pkg/fileutil/purge.go b/vendor/go.etcd.io/etcd/pkg/fileutil/purge.go
new file mode 100644
index 0000000..fda96c3
--- /dev/null
+++ b/vendor/go.etcd.io/etcd/pkg/fileutil/purge.go
@@ -0,0 +1,88 @@
+// Copyright 2015 The etcd Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package fileutil
+
+import (
+	"os"
+	"path/filepath"
+	"sort"
+	"strings"
+	"time"
+
+	"go.uber.org/zap"
+)
+
+func PurgeFile(lg *zap.Logger, dirname string, suffix string, max uint, interval time.Duration, stop <-chan struct{}) <-chan error {
+	return purgeFile(lg, dirname, suffix, max, interval, stop, nil)
+}
+
+// purgeFile is the internal implementation for PurgeFile which can post purged files to purgec if non-nil.
+func purgeFile(lg *zap.Logger, dirname string, suffix string, max uint, interval time.Duration, stop <-chan struct{}, purgec chan<- string) <-chan error {
+	errC := make(chan error, 1)
+	go func() {
+		for {
+			fnames, err := ReadDir(dirname)
+			if err != nil {
+				errC <- err
+				return
+			}
+			newfnames := make([]string, 0)
+			for _, fname := range fnames {
+				if strings.HasSuffix(fname, suffix) {
+					newfnames = append(newfnames, fname)
+				}
+			}
+			sort.Strings(newfnames)
+			fnames = newfnames
+			for len(newfnames) > int(max) {
+				f := filepath.Join(dirname, newfnames[0])
+				l, err := TryLockFile(f, os.O_WRONLY, PrivateFileMode)
+				if err != nil {
+					break
+				}
+				if err = os.Remove(f); err != nil {
+					errC <- err
+					return
+				}
+				if err = l.Close(); err != nil {
+					if lg != nil {
+						lg.Warn("failed to unlock/close", zap.String("path", l.Name()), zap.Error(err))
+					} else {
+						plog.Errorf("error unlocking %s when purging file (%v)", l.Name(), err)
+					}
+					errC <- err
+					return
+				}
+				if lg != nil {
+					lg.Info("purged", zap.String("path", f))
+				} else {
+					plog.Infof("purged file %s successfully", f)
+				}
+				newfnames = newfnames[1:]
+			}
+			if purgec != nil {
+				for i := 0; i < len(fnames)-len(newfnames); i++ {
+					purgec <- fnames[i]
+				}
+			}
+			select {
+			case <-time.After(interval):
+			case <-stop:
+				return
+			}
+		}
+	}()
+	return errC
+}