fix SSD

reddec · Mar 19, 2021 · 999edec · 999edec
1 parent 155d619
commit 999edec
Show file tree

Hide file tree

Showing 3 changed files with 21 additions and 13 deletions.
diff --git a/cmd/tinc-boot/run/main.go b/cmd/tinc-boot/run/main.go
@@ -157,8 +157,7 @@ func (cmd *Cmd) Execute([]string) error {
 	}
 	for _, host := range hosts {
 		ssd.ReplaceIfNewer(discovery.Entity{
-			Name:    host,
-			Version: 0,
+			Name: host,
 		}, nil)
 	}
 
@@ -243,7 +242,9 @@ func (cmd *Cmd) Execute([]string) error {
 			}, nil) {
 				log.Println("got new node", name, "from", url)
 			}
-			_ = ssd.Save()
+			if err := ssd.Save(); err != nil {
+				log.Println("failed save discovery metadata after exchange:", err)
+			}
 		}
 		greetClients.Add(1)
 		go func(client *boot.Client) {
@@ -260,7 +261,9 @@ func (cmd *Cmd) Execute([]string) error {
 			Name:    info.Name,
 			Version: 0,
 		}, nil)
-		_ = ssd.Save()
+		if err := ssd.Save(); err != nil {
+			log.Println("failed save discovery metadata:", err)
+		}
 	}
 
 	greetServer := &http.Server{

diff --git a/tincd/discovery/server.go b/tincd/discovery/server.go
@@ -46,7 +46,7 @@ func (srv *server) getOne(writer http.ResponseWriter, request *http.Request) {
 
 	log.Println("asking for", name, "after", version)
 
-	info, ok := srv.ssd.GetIfNewer(name, version)
+	info, ok := srv.ssd.GetAfter(name, version)
 	if !ok {
 		http.NotFound(writer, request)
 		return

diff --git a/tincd/discovery/ssd.go b/tincd/discovery/ssd.go
@@ -28,16 +28,18 @@ type SSD struct {
 	lock     sync.RWMutex
 	entities map[string]Entity
 	file     string
+	fileLock sync.Mutex
+}
+
+func (ssd *SSD) unsafeIsNewer(name string, desired int64) bool {
+	old, exists := ssd.entities[name]
+	return !exists || desired > old.Version
 }
 
 func (ssd *SSD) CanBeMerged(entity Entity) bool {
 	ssd.lock.RLock()
 	defer ssd.lock.RUnlock()
-	old, hasOld := ssd.entities[entity.Name]
-	if !hasOld || old.Version <= entity.Version {
-		return false
-	}
-	return true
+	return ssd.unsafeIsNewer(entity.Name, entity.Version)
 }
 
 func (ssd *SSD) ReplaceIfNewer(entity Entity, block func() bool) bool {
@@ -46,8 +48,7 @@ func (ssd *SSD) ReplaceIfNewer(entity Entity, block func() bool) bool {
 	if ssd.entities == nil {
 		ssd.entities = make(map[string]Entity)
 	}
-	old, hasOld := ssd.entities[entity.Name]
-	if hasOld && old.Version <= entity.Version {
+	if !ssd.unsafeIsNewer(entity.Name, entity.Version) {
 		return false
 	}
 	if block != nil && !block() {
@@ -66,7 +67,7 @@ func (ssd *SSD) Replace(entity Entity) {
 	ssd.entities[entity.Name] = entity
 }
 
-func (ssd *SSD) GetIfNewer(name string, version int64) (Entity, bool) {
+func (ssd *SSD) GetAfter(name string, version int64) (Entity, bool) {
 	ssd.lock.RLock()
 	defer ssd.lock.RUnlock()
 	old, hasOld := ssd.entities[name]
@@ -158,10 +159,14 @@ func (ssd *SSD) ReadFile(filename string) error {
 }
 
 func (ssd *SSD) Read() error {
+	ssd.fileLock.Lock()
+	defer ssd.fileLock.Unlock()
 	return ssd.ReadFile(ssd.file)
 }
 
 func (ssd *SSD) Save() error {
+	ssd.fileLock.Lock()
+	defer ssd.fileLock.Unlock()
 	return ssd.SaveFile(ssd.file)
 }