From 152dcdba07c55c0ddec62fd290dee4b2e600fa0a Mon Sep 17 00:00:00 2001
From: fanmin shi <fanmin.shi@coreos.com>
Date: Mon, 21 Nov 2016 16:04:05 -0800
Subject: [PATCH] lease: use monotimer for lease

lease uses monotimer to calculate its expiration. In this way, changing system time won't affect in lease expiration.

FIX #6700
---
 build           |  4 ++--
 lease/lessor.go | 15 ++++++++-------
 2 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/build b/build
index b1fc8d43b97e..fe0267936fce 100755
--- a/build
+++ b/build
@@ -35,8 +35,8 @@ etcd_build() {
 	if [ -n "${BINDIR}" ]; then out="${BINDIR}"; fi
 	toggle_failpoints
 	# Static compilation is useful when etcd is run in a container
-	CGO_ENABLED=0 go build $GO_BUILD_FLAGS -installsuffix cgo -ldflags "$GO_LDFLAGS" -o ${out}/etcd ${REPO_PATH}/cmd/etcd || return
-	CGO_ENABLED=0 go build $GO_BUILD_FLAGS -installsuffix cgo -ldflags "$GO_LDFLAGS" -o ${out}/etcdctl ${REPO_PATH}/cmd/etcdctl || return
+	go build $GO_BUILD_FLAGS -installsuffix cgo -ldflags "$GO_LDFLAGS" -o ${out}/etcd ${REPO_PATH}/cmd/etcd || return
+	go build $GO_BUILD_FLAGS -installsuffix cgo -ldflags "$GO_LDFLAGS" -o ${out}/etcdctl ${REPO_PATH}/cmd/etcdctl || return
 }
 
 etcd_setup_gopath() {
diff --git a/lease/lessor.go b/lease/lessor.go
index 45ed881b6734..126b4b031e63 100644
--- a/lease/lessor.go
+++ b/lease/lessor.go
@@ -22,6 +22,7 @@ import (
 	"sync"
 	"time"
 
+	"github.com/ScaleFT/monotime"
 	"github.com/coreos/etcd/lease/leasepb"
 	"github.com/coreos/etcd/mvcc/backend"
 )
@@ -33,9 +34,9 @@ const (
 
 var (
 	leaseBucketName = []byte("lease")
-	// do not use maxInt64 since it can overflow time which will add
-	// the offset of unix time (1970yr to seconds).
-	forever = time.Unix(math.MaxInt64>>1, 0)
+
+	monoTimer = monotime.New()
+	forever   = time.Duration(1>>63 - 1)
 
 	ErrNotPrimary    = errors.New("not a primary lessor")
 	ErrLeaseNotFound = errors.New("lease not found")
@@ -504,8 +505,8 @@ type Lease struct {
 	ttl int64 // time to live in seconds
 
 	itemSet map[LeaseItem]struct{}
-	// expiry time in unixnano
-	expiry  time.Time
+	// expiry is time when lease should expire
+	expiry  time.Duration
 	revokec chan struct{}
 }
 
@@ -534,7 +535,7 @@ func (l *Lease) TTL() int64 {
 
 // refresh refreshes the expiry of the lease.
 func (l *Lease) refresh(extend time.Duration) {
-	l.expiry = time.Now().Add(extend + time.Second*time.Duration(l.ttl))
+	l.expiry = extend + monoTimer.Elapsed() + time.Duration(l.ttl)*time.Second
 }
 
 // forever sets the expiry of lease to be forever.
@@ -551,7 +552,7 @@ func (l *Lease) Keys() []string {
 
 // Remaining returns the remaining time of the lease.
 func (l *Lease) Remaining() time.Duration {
-	return l.expiry.Sub(time.Now())
+	return l.expiry - monoTimer.Elapsed()
 }
 
 type LeaseItem struct {