fix enforcing volume size limit

git-svn-id: https://weed-fs.googlecode.com/svn/trunk@34 282b0af5-e82d-9cf1-ede4-77906d7719d0

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

@@ -30,8 +30,8 @@ type Mapper struct {
 
 	lock          sync.Mutex
 	Machines      []*Machine
-	vid2machineId map[uint32]int
-	Writers       []int // transient array of Writers volume id
+	vid2machineId map[uint32]int //machineId is +1 of the index of []*Machine, to detect not found entries
+	Writers       []uint32 // transient array of Writers volume id
 
 	FileIdSequence uint64
 	fileIdCounter  uint64
@@ -47,7 +47,7 @@ func NewMapper(dirname string, filename string, volumeSizeLimit uint32) (m *Mapp
 	m = &Mapper{dir: dirname, fileName: filename}
 	m.vid2machineId = make(map[uint32]int)
 	m.volumeSizeLimit = volumeSizeLimit
-	m.Writers = *new([]int)
+	m.Writers = *new([]uint32)
 	m.Machines = *new([]*Machine)
 
 	seqFile, se := os.OpenFile(path.Join(m.dir, m.fileName+".seq"), os.O_RDONLY, 0644)
@@ -70,10 +70,14 @@ func (m *Mapper) PickForWrite() (string, MachineInfo, os.Error) {
 		log.Println("No more writable volumes!")
 		return "", m.Machines[rand.Intn(len(m.Machines))].Server, os.NewError("No more writable volumes!")
 	}
-	machine := m.Machines[m.Writers[rand.Intn(len_writers)]]
-	vid := machine.Volumes[rand.Intn(len(machine.Volumes))].Id
+	vid := m.Writers[rand.Intn(len_writers)]
+	machine_id := m.vid2machineId[vid]
+	if machine_id > 0 {
+		machine := m.Machines[machine_id-1]
 		return NewFileId(vid, m.NextFileId(), rand.Uint32()).String(), machine.Server, nil
 	}
+	return "", m.Machines[rand.Intn(len(m.Machines))].Server, os.NewError("Strangely vid " + strconv.Uitoa64(uint64(vid)) + " is on no machine!")
+}
 func (m *Mapper) NextFileId() uint64 {
 	if m.fileIdCounter <= 0 {
 		m.fileIdCounter = FileIdSaveInterval
@@ -115,11 +119,11 @@ func (m *Mapper) Add(machine Machine){
 		m.vid2machineId[v.Id] = machineId + 1 //use base 1 indexed, to detect not found cases
 	}
 	//setting Writers, copy-on-write because of possible updating
-	var writers []int
-	for machine_index, machine_entry := range m.Machines {
+	var writers []uint32
+	for _, machine_entry := range m.Machines {
 		for _, v := range machine_entry.Volumes {
 			if v.Size < int64(m.volumeSizeLimit) {
-				writers = append(writers, machine_index)
+				writers = append(writers, v.Id)
 			}
 		}
 	}