fix sbft checkpoint backlog bug

Checkpoints were never backloged in sbft. Variable naming was obscuring the
issue.

Piggybacked some refactoring and cleanup.

Change-Id: I8f08d8ea30a00cf9bc4f22b697d81d1790d6bc37
Signed-off-by: Marko Vukolic <mvu@zurich.ibm.com>

orderer/sbft/simplebft/backlog.go

@@ -22,7 +22,7 @@ const maxBacklogSeq = 4
 const msgPerSeq = 3 // (pre)prepare, commit, checkpoint
 
 func (s *SBFT) testBacklogMessage(m *Msg, src uint64) bool {
- record := func(seq *SeqView) bool {
+ test := func(seq *SeqView) bool {
  if !s.activeView {
  return true
  }
@@ -33,14 +33,13 @@ func (s *SBFT) testBacklogMessage(m *Msg, src uint64) bool {
  }
 
  if pp := m.GetPreprepare(); pp != nil {
- return record(pp.Seq) && !s.cur.checkpointDone
+ return test(pp.Seq) && !s.cur.checkpointDone
  } else if p := m.GetPrepare(); p != nil {
- return record(p.Seq)
+ return test(p.Seq)
  } else if c := m.GetCommit(); c != nil {
- return record(c.Seq)
- } else if cs := m.GetCheckpoint(); cs != nil {
- c := &Checkpoint{}
- return record(&SeqView{Seq: c.Seq})
+ return test(c.Seq)
+ } else if chk := m.GetCheckpoint(); chk != nil {
+ return test(&SeqView{Seq: chk.Seq})
  }
  return false
 }
@@ -53,6 +52,7 @@ func (s *SBFT) recordBacklogMsg(m *Msg, src uint64) {
  s.replicaState[src].backLog = append(s.replicaState[src].backLog, m)
 
  if len(s.replicaState[src].backLog) > maxBacklogSeq*msgPerSeq {
+ log.Debugf("replica %d: backlog for %d full, discarding and reconnecting", s.id, src)
  s.discardBacklog(src)
  s.sys.Reconnect(src)
  }
@@ -64,7 +64,6 @@ func (s *SBFT) discardBacklog(src uint64) {
 
 func (s *SBFT) processBacklog() {
  processed := true
- notReady := uint64(0)
 
  for processed {
  processed = false
@@ -75,7 +74,6 @@ func (s *SBFT) processBacklog() {
  for len(state.backLog) > 0 {
  m, rest := state.backLog[0], state.backLog[1:]
  if s.testBacklogMessage(m, src) {
- notReady++
  break
  }
  state.backLog = rest