git-svn-id: https://weed-fs.googlecode.com/svn/trunk@12 282b0af5-e82d-9cf1-ede4-77906d7719d0

weed-fs/src/pkg/directory/volume_mapping.go

@@ -12,12 +12,14 @@ import (
 type Machine struct {
 	Server       string //<server name/ip>[:port]
 	PublicServer string
+	CanWrite     bool
 }
 type Mapper struct {
-    dir              string
-    FileName         string
-    Id2Machine map[uint32][]*Machine
-    LastId uint32
+	dir      string
+	fileName string
+	capacity int
+	Machines [][]Machine //initial version only support one copy per machine
+	writers  [][]Machine // transient value to lookup writers fast
 }
 
 func NewMachine(server, publicServer string) (m *Machine) {
@@ -26,57 +28,88 @@ func NewMachine(server, publicServer string) (m *Machine) {
 	return
 }
 
-func NewMapper(dirname string, filename string) (m *Mapper) {
+func NewMapper(dirname string, filename string, capacity int) (m *Mapper) {
 	m = new(Mapper)
-	m.dir = dirname
-	m.FileName = filename
-	log.Println("Loading virtual to physical:", path.Join(m.dir,m.FileName+".map"))
-	dataFile, e := os.OpenFile(path.Join(m.dir,m.FileName+".map"), os.O_RDONLY, 0644)
-	m.Id2Machine = make(map[uint32][]*Machine)
+	m.dir, m.fileName, m.capacity = dirname, filename, capacity
+	log.Println("Loading volume id to maching mapping:", path.Join(m.dir, m.fileName+".map"))
+	dataFile, e := os.OpenFile(path.Join(m.dir, m.fileName+".map"), os.O_RDONLY, 0644)
+	m.Machines = *new([][]Machine)
+	m.writers = *new([][]Machine)
 	if e != nil {
 		log.Println("Mapping File Read", e)
 	} else {
 		decoder := gob.NewDecoder(dataFile)
-        decoder.Decode(m.LastId)
-		decoder.Decode(m.Id2Machine)
+		decoder.Decode(m.Machines)
+		for _, list := range m.Machines {
+			//TODO: what if a list has mixed readers and writers? Now it's treated as readonly
+			allCanWrite := false
+			for _, entry := range list {
+				allCanWrite = allCanWrite && entry.CanWrite
+			}
+			if allCanWrite {
+				m.writers = append(m.writers, list)
+			}
+		}
 		dataFile.Close()
+        log.Println("Loaded mapping size", len(m.Machines))
 	}
 	return
 }
-func (m *Mapper) PickForWrite() []*Machine {
-	vid := uint32(rand.Intn(len(m.Id2Machine)))
-	return m.Id2Machine[vid]
+func (m *Mapper) PickForWrite() []Machine {
+	vid := rand.Intn(len(m.Machines))
+	return m.Machines[vid]
 }
-func (m *Mapper) Get(vid uint32) []*Machine {
-	return m.Id2Machine[vid]
+func (m *Mapper) Get(vid int) []Machine {
+	return m.Machines[vid]
 }
-func (m *Mapper) Add(machine *Machine, volumes []storage.VolumeStat) {
-    log.Println("Adding store node", machine.Server)
+func (m *Mapper) Add(machine Machine, volumes []storage.VolumeStat, capacity int) []int {
+	log.Println("Adding existing", machine.Server, len(volumes), "volumes to dir", len(m.Machines))
+    log.Println("Adding      new ", machine.Server, capacity - len(volumes), "volumes to dir", len(m.Machines))
+	maxId := len(m.Machines)-1
+	for _, v := range volumes {
+		if maxId < int(v.Id) {
+			maxId = int(v.Id)
+		}
+	}
+	for i := len(m.Machines); i <= maxId; i++ {
+		m.Machines = append(m.Machines, nil)
+	}
+    log.Println("Machine list now is", len(m.Machines))
 	for _, v := range volumes {
-		existing := m.Id2Machine[uint32(v.Id)]
 		found := false
+		existing := m.Machines[v.Id]
 		for _, entry := range existing {
-			if machine == entry {
+			if machine.Server == entry.Server {
 				found = true
 				break
 			}
 		}
 		if !found {
-			m.Id2Machine[uint32(v.Id)] = append(existing, machine)
+			m.Machines[v.Id] = append(existing, machine)
+			log.Println("Setting volume", v.Id, "to", machine.Server)
 		}
-        log.Println(v.Id, "=>", machine.Server)
 	}
+
+    vids := new([]int)
+	for vid,i := len(m.Machines),len(volumes); i < capacity; i,vid=i+1,vid+1 {
+		list := new([]Machine)
+		*list = append(*list, machine)
+		m.Machines = append(m.Machines, *list)
+		log.Println("Adding volume", vid, "from", machine.Server)
+		*vids = append(*vids, vid)
+	}
+
 	m.Save()
+	log.Println("Dir size =>", len(m.Machines))
+	return *vids
 }
 func (m *Mapper) Save() {
-	log.Println("Saving virtual to physical:", path.Join(m.dir,m.FileName+".map"))
-	dataFile, e := os.OpenFile(path.Join(m.dir,m.FileName+".map"), os.O_CREATE|os.O_WRONLY, 0644)
+	log.Println("Saving virtual to physical:", path.Join(m.dir, m.fileName+".map"))
+	dataFile, e := os.OpenFile(path.Join(m.dir, m.fileName+".map"), os.O_CREATE|os.O_WRONLY, 0644)
 	if e != nil {
 		log.Fatalf("Mapping File Save [ERROR] %s\n", e)
 	}
 	defer dataFile.Close()
-	m.Id2Machine = make(map[uint32][]*Machine)
 	encoder := gob.NewEncoder(dataFile)
-    encoder.Encode(m.LastId)
-	encoder.Encode(m.Id2Machine)
+	encoder.Encode(m.Machines)
 }