correcting free volume count, factor it during ec encoding to ensure enough disk space available

fix https://github.com/seaweedfs/seaweedfs/issues/6163

weed/shell/command_ec_encode.go

@@ -315,15 +315,31 @@ func collectVolumeIdsForEcEncode(commandEnv *CommandEnv, selectedCollection stri
 				}
 				if v.Collection == selectedCollection && v.ModifiedAtSecond+quietSeconds < nowUnixSeconds {
 					if float64(v.Size) > fullPercentage/100*float64(volumeSizeLimitMb)*1024*1024 {
-						vidMap[v.Id] = true
+						if good, found := vidMap[v.Id]; found {
+							if good {
+								if diskInfo.FreeVolumeCount < 1 {
+									glog.V(0).Infof("skip %d.%d on %s, no free disk", v.Id, v.Collection, dn.Id)
+									vidMap[v.Id] = false
+								}
+							}
+						} else {
+							if diskInfo.FreeVolumeCount < 1 {
+								glog.V(0).Infof("skip %d.%d on %s, no free disk", v.Id, v.Collection, dn.Id)
+								vidMap[v.Id] = false
+							} else {
+								vidMap[v.Id] = true
+							}
+						}
 					}
 				}
 			}
 		}
 	})
 
-	for vid := range vidMap {
-		vids = append(vids, needle.VolumeId(vid))
+	for vid, good := range vidMap {
+		if good {
+			vids = append(vids, needle.VolumeId(vid))
+		}
 	}
 
 	return

weed/topology/disk.go

@@ -66,7 +66,7 @@ func (d *DiskUsages) ToDiskInfo() map[string]*master_pb.DiskInfo {
 		m := &master_pb.DiskInfo{
 			VolumeCount:       diskUsageCounts.volumeCount,
 			MaxVolumeCount:    diskUsageCounts.maxVolumeCount,
-			FreeVolumeCount:   diskUsageCounts.maxVolumeCount - diskUsageCounts.volumeCount,
+			FreeVolumeCount:   diskUsageCounts.maxVolumeCount - (diskUsageCounts.volumeCount - diskUsageCounts.remoteVolumeCount) - (diskUsageCounts.ecShardCount+1)/erasure_coding.DataShardsCount,
 			ActiveVolumeCount: diskUsageCounts.activeVolumeCount,
 			RemoteVolumeCount: diskUsageCounts.remoteVolumeCount,
 		}
@@ -250,7 +250,7 @@ func (d *Disk) ToDiskInfo() *master_pb.DiskInfo {
 		Type:              string(d.Id()),
 		VolumeCount:       diskUsage.volumeCount,
 		MaxVolumeCount:    diskUsage.maxVolumeCount,
-		FreeVolumeCount:   diskUsage.maxVolumeCount - diskUsage.volumeCount,
+		FreeVolumeCount:   diskUsage.maxVolumeCount - (diskUsage.volumeCount - diskUsage.remoteVolumeCount) - (diskUsage.ecShardCount+1)/erasure_coding.DataShardsCount,
 		ActiveVolumeCount: diskUsage.activeVolumeCount,
 		RemoteVolumeCount: diskUsage.remoteVolumeCount,
 	}