ahead of time volume assignment

weed/topology/volume_layout.go

@@ -27,6 +27,7 @@ type volumeState string
 const (
 	readOnlyState  volumeState = "ReadOnly"
 	oversizedState             = "Oversized"
+	crowdedState               = "Crowded"
 )
 
 type stateIndicator func(copyState) bool
@@ -106,7 +107,8 @@ type VolumeLayout struct {
 	ttl              *needle.TTL
 	diskType         types.DiskType
 	vid2location     map[needle.VolumeId]*VolumeLocationList
-	writables        []needle.VolumeId   // transient array of writable volume id
+	writables        []needle.VolumeId // transient array of writable volume id
+	crowded          map[needle.VolumeId]interface{}
 	readonlyVolumes  *volumesBinaryState // readonly volumes
 	oversizedVolumes *volumesBinaryState // oversized volumes
 	volumeSizeLimit  uint64
@@ -127,6 +129,7 @@ func NewVolumeLayout(rp *super_block.ReplicaPlacement, ttl *needle.TTL, diskType
 		diskType:         diskType,
 		vid2location:     make(map[needle.VolumeId]*VolumeLocationList),
 		writables:        *new([]needle.VolumeId),
+		crowded:          make(map[needle.VolumeId]interface{}),
 		readonlyVolumes:  NewVolumesBinaryState(readOnlyState, rp, ExistCopies()),
 		oversizedVolumes: NewVolumesBinaryState(oversizedState, rp, ExistCopies()),
 		volumeSizeLimit:  volumeSizeLimit,
@@ -273,7 +276,7 @@ func (vl *VolumeLayout) PickForWrite(count uint64, option *VolumeGrowOption) (*n
 
 	lenWriters := len(vl.writables)
 	if lenWriters <= 0 {
-		glog.V(0).Infoln("No more writable volumes!")
+		//glog.V(0).Infoln("No more writable volumes!")
 		return nil, 0, nil, errors.New("No more writable volumes!")
 	}
 	if option.DataCenter == "" {
@@ -307,14 +310,13 @@ func (vl *VolumeLayout) PickForWrite(count uint64, option *VolumeGrowOption) (*n
 	return &vid, count, locationList, nil
 }
 
-func (vl *VolumeLayout) GetActiveVolumeCount(option *VolumeGrowOption) int {
+func (vl *VolumeLayout) GetActiveVolumeCount(option *VolumeGrowOption) (active, crowded int) {
 	vl.accessLock.RLock()
 	defer vl.accessLock.RUnlock()
 
 	if option.DataCenter == "" {
-		return len(vl.writables)
+		return len(vl.writables), len(vl.crowded)
 	}
-	counter := 0
 	for _, v := range vl.writables {
 		for _, dn := range vl.vid2location[v].list {
 			if dn.GetDataCenter().Id() == NodeId(option.DataCenter) {
@@ -324,11 +326,15 @@ func (vl *VolumeLayout) GetActiveVolumeCount(option *VolumeGrowOption) int {
 				if option.DataNode != "" && dn.Id() != NodeId(option.DataNode) {
 					continue
 				}
-				counter++
+				active++
+				info, _ := dn.GetVolumesById(v)
+				if float64(info.Size) > float64(vl.volumeSizeLimit)*option.Threshold() {
+					crowded++
+				}
 			}
 		}
 	}
-	return counter
+	return
 }
 
 func (vl *VolumeLayout) removeFromWritable(vid needle.VolumeId) bool {
@@ -342,6 +348,7 @@ func (vl *VolumeLayout) removeFromWritable(vid needle.VolumeId) bool {
 	if toDeleteIndex >= 0 {
 		glog.V(0).Infoln("Volume", vid, "becomes unwritable")
 		vl.writables = append(vl.writables[0:toDeleteIndex], vl.writables[toDeleteIndex+1:]...)
+		vl.removeFromCrowded(vid)
 		return true
 	}
 	return false
@@ -408,6 +415,32 @@ func (vl *VolumeLayout) SetVolumeCapacityFull(vid needle.VolumeId) bool {
 	return vl.removeFromWritable(vid)
 }
 
+func (vl *VolumeLayout) removeFromCrowded(vid needle.VolumeId) {
+	delete(vl.crowded, vid)
+}
+
+func (vl *VolumeLayout) setVolumeCrowded(vid needle.VolumeId) {
+	if _, ok := vl.crowded[vid]; !ok {
+		vl.crowded[vid] = nil
+		glog.V(0).Infoln("Volume", vid, "becomes crowded")
+	}
+}
+
+func (vl *VolumeLayout) SetVolumeCrowded(vid needle.VolumeId) {
+	// since delete is guarded by accessLock.Lock(),
+	// and is always called in sequential order,
+	// RLock() should be safe enough
+	vl.accessLock.RLock()
+	defer vl.accessLock.RUnlock()
+
+	for _, v := range vl.writables {
+		if v == vid {
+			vl.setVolumeCrowded(vid)
+			break
+		}
+	}
+}
+
 func (vl *VolumeLayout) ToMap() map[string]interface{} {
 	m := make(map[string]interface{})
 	m["replication"] = vl.rp.String()