diff --git a/vendor/github.com/coreos/etcd/clientv3/concurrency/mutex.go b/vendor/github.com/coreos/etcd/clientv3/concurrency/mutex.go
new file mode 100644
index 0000000..77b3582
--- /dev/null
+++ b/vendor/github.com/coreos/etcd/clientv3/concurrency/mutex.go
@@ -0,0 +1,117 @@
+// Copyright 2016 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 concurrency
+
+import (
+	"context"
+	"fmt"
+	"sync"
+
+	v3 "github.com/coreos/etcd/clientv3"
+	pb "github.com/coreos/etcd/etcdserver/etcdserverpb"
+)
+
+// Mutex implements the sync Locker interface with etcd
+type Mutex struct {
+	s *Session
+
+	pfx   string
+	myKey string
+	myRev int64
+	hdr   *pb.ResponseHeader
+}
+
+func NewMutex(s *Session, pfx string) *Mutex {
+	return &Mutex{s, pfx + "/", "", -1, nil}
+}
+
+// Lock locks the mutex with a cancelable context. If the context is canceled
+// while trying to acquire the lock, the mutex tries to clean its stale lock entry.
+func (m *Mutex) Lock(ctx context.Context) error {
+	s := m.s
+	client := m.s.Client()
+
+	m.myKey = fmt.Sprintf("%s%x", m.pfx, s.Lease())
+	cmp := v3.Compare(v3.CreateRevision(m.myKey), "=", 0)
+	// put self in lock waiters via myKey; oldest waiter holds lock
+	put := v3.OpPut(m.myKey, "", v3.WithLease(s.Lease()))
+	// reuse key in case this session already holds the lock
+	get := v3.OpGet(m.myKey)
+	// fetch current holder to complete uncontended path with only one RPC
+	getOwner := v3.OpGet(m.pfx, v3.WithFirstCreate()...)
+	resp, err := client.Txn(ctx).If(cmp).Then(put, getOwner).Else(get, getOwner).Commit()
+	if err != nil {
+		return err
+	}
+	m.myRev = resp.Header.Revision
+	if !resp.Succeeded {
+		m.myRev = resp.Responses[0].GetResponseRange().Kvs[0].CreateRevision
+	}
+	// if no key on prefix / the minimum rev is key, already hold the lock
+	ownerKey := resp.Responses[1].GetResponseRange().Kvs
+	if len(ownerKey) == 0 || ownerKey[0].CreateRevision == m.myRev {
+		m.hdr = resp.Header
+		return nil
+	}
+
+	// wait for deletion revisions prior to myKey
+	hdr, werr := waitDeletes(ctx, client, m.pfx, m.myRev-1)
+	// release lock key if wait failed
+	if werr != nil {
+		m.Unlock(client.Ctx())
+	} else {
+		m.hdr = hdr
+	}
+	return werr
+}
+
+func (m *Mutex) Unlock(ctx context.Context) error {
+	client := m.s.Client()
+	if _, err := client.Delete(ctx, m.myKey); err != nil {
+		return err
+	}
+	m.myKey = "\x00"
+	m.myRev = -1
+	return nil
+}
+
+func (m *Mutex) IsOwner() v3.Cmp {
+	return v3.Compare(v3.CreateRevision(m.myKey), "=", m.myRev)
+}
+
+func (m *Mutex) Key() string { return m.myKey }
+
+// Header is the response header received from etcd on acquiring the lock.
+func (m *Mutex) Header() *pb.ResponseHeader { return m.hdr }
+
+type lockerMutex struct{ *Mutex }
+
+func (lm *lockerMutex) Lock() {
+	client := lm.s.Client()
+	if err := lm.Mutex.Lock(client.Ctx()); err != nil {
+		panic(err)
+	}
+}
+func (lm *lockerMutex) Unlock() {
+	client := lm.s.Client()
+	if err := lm.Mutex.Unlock(client.Ctx()); err != nil {
+		panic(err)
+	}
+}
+
+// NewLocker creates a sync.Locker backed by an etcd mutex.
+func NewLocker(s *Session, pfx string) sync.Locker {
+	return &lockerMutex{NewMutex(s, pfx)}
+}