refactor: replace TotalShards field with Total() method

- Remove TotalShards field from ECContext to avoid field drift
- Add Total() method that computes DataShards + ParityShards
- Update all references to use ctx.Total() instead of ctx.TotalShards
- Read EC config from VolumeInfo when loading EC volumes
- Read data shard count from .vif in VolumeEcShardsToVolume
- Use >= instead of > for exact boundary handling in encoding loops

weed/server/volume_grpc_erasure_coding.go

@@ -59,7 +59,7 @@ func (vs *VolumeServer) VolumeEcShardsGenerate(ctx context.Context, req *volume_
 		if !shouldCleanup {
 			return
 		}
-		for i := 0; i < ecCtx.TotalShards; i++ {
+		for i := 0; i < ecCtx.Total(); i++ {
 			os.Remove(baseFileName + ecCtx.ToExt(i))
 		}
 		os.Remove(v.IndexFileName() + ".ecx")
@@ -453,9 +453,27 @@ func (vs *VolumeServer) VolumeEcShardsToVolume(ctx context.Context, req *volume_
 
 	glog.V(0).Infof("VolumeEcShardsToVolume: %v", req)
 
-	// collect .ec00 ~ .ec09 files
-	shardFileNames := make([]string, erasure_coding.DataShardsCount)
-	v, found := vs.store.CollectEcShards(needle.VolumeId(req.VolumeId), shardFileNames)
+	// collect data shard files; derive shard count from .vif if present
+	dataShards := erasure_coding.DataShardsCount
+	
+	// Try to get the volume first to determine data base filename
+	tempShards := make([]string, erasure_coding.TotalShardsCount)
+	v, found := vs.store.CollectEcShards(needle.VolumeId(req.VolumeId), tempShards)
+	if !found {
+		return nil, fmt.Errorf("ec volume %d not found", req.VolumeId)
+	}
+	
+	dataBaseFileName, indexBaseFileName := v.DataBaseFileName(), v.IndexBaseFileName()
+	
+	// Read EC config from .vif if available
+	if vi, _, found, _ := volume_info.MaybeLoadVolumeInfo(dataBaseFileName + ".vif"); found && vi.EcShardConfig != nil {
+		dataShards = int(vi.EcShardConfig.DataShards)
+		glog.V(1).Infof("Using EC config from VolumeInfo: %d data shards", dataShards)
+	}
+	
+	// Collect only the data shards needed
+	shardFileNames := make([]string, dataShards)
+	v, found = vs.store.CollectEcShards(needle.VolumeId(req.VolumeId), shardFileNames)
 	if !found {
 		return nil, fmt.Errorf("ec volume %d not found", req.VolumeId)
 	}
@@ -464,13 +482,11 @@ func (vs *VolumeServer) VolumeEcShardsToVolume(ctx context.Context, req *volume_
 		return nil, fmt.Errorf("existing collection:%v unexpected input: %v", v.Collection, req.Collection)
 	}
 
-	for shardId := 0; shardId < erasure_coding.DataShardsCount; shardId++ {
+	for shardId := 0; shardId < dataShards; shardId++ {
 		if shardFileNames[shardId] == "" {
 			return nil, fmt.Errorf("ec volume %d missing shard %d", req.VolumeId, shardId)
 		}
 	}
-
-	dataBaseFileName, indexBaseFileName := v.DataBaseFileName(), v.IndexBaseFileName()
 	// calculate .dat file size
 	datFileSize, err := erasure_coding.FindDatFileSize(dataBaseFileName, indexBaseFileName)
 	if err != nil {

weed/storage/erasure_coding/ec_context.go

@@ -11,17 +11,20 @@ import (
 type ECContext struct {
 	DataShards   int
 	ParityShards int
-	TotalShards  int
 	Collection   string
 	VolumeId     needle.VolumeId
 }
 
+// Total returns the total number of shards (data + parity)
+func (ctx *ECContext) Total() int {
+	return ctx.DataShards + ctx.ParityShards
+}
+
 // NewDefaultECContext creates a context with default 10+4 shard configuration
 func NewDefaultECContext(collection string, volumeId needle.VolumeId) *ECContext {
 	return &ECContext{
 		DataShards:   DataShardsCount,
 		ParityShards: ParityShardsCount,
-		TotalShards:  TotalShardsCount,
 		Collection:   collection,
 		VolumeId:     volumeId,
 	}
@@ -39,5 +42,5 @@ func (ctx *ECContext) ToExt(shardIndex int) string {
 
 // String returns a human-readable representation of the EC configuration
 func (ctx *ECContext) String() string {
-	return fmt.Sprintf("%d+%d (total: %d)", ctx.DataShards, ctx.ParityShards, ctx.TotalShards)
+	return fmt.Sprintf("%d+%d (total: %d)", ctx.DataShards, ctx.ParityShards, ctx.Total())
 }

weed/storage/erasure_coding/ec_encoder.go

@@ -101,10 +101,10 @@ func generateEcFiles(baseFileName string, bufferSize int, largeBlockSize int64,
 
 func generateMissingEcFiles(baseFileName string, bufferSize int, largeBlockSize int64, smallBlockSize int64, ctx *ECContext) (generatedShardIds []uint32, err error) {
 
-	shardHasData := make([]bool, ctx.TotalShards)
-	inputFiles := make([]*os.File, ctx.TotalShards)
-	outputFiles := make([]*os.File, ctx.TotalShards)
-	for shardId := 0; shardId < ctx.TotalShards; shardId++ {
+	shardHasData := make([]bool, ctx.Total())
+	inputFiles := make([]*os.File, ctx.Total())
+	outputFiles := make([]*os.File, ctx.Total())
+	for shardId := 0; shardId < ctx.Total(); shardId++ {
 		shardFileName := baseFileName + ctx.ToExt(shardId)
 		if util.FileExists(shardFileName) {
 			shardHasData[shardId] = true
@@ -153,7 +153,7 @@ func encodeData(file *os.File, enc reedsolomon.Encoder, startOffset, blockSize i
 }
 
 func openEcFiles(baseFileName string, forRead bool, ctx *ECContext) (files []*os.File, err error) {
-	for i := 0; i < ctx.TotalShards; i++ {
+	for i := 0; i < ctx.Total(); i++ {
 		fname := baseFileName + ctx.ToExt(i)
 		openOption := os.O_TRUNC | os.O_CREATE | os.O_WRONLY
 		if forRead {
@@ -198,7 +198,7 @@ func encodeDataOneBatch(file *os.File, enc reedsolomon.Encoder, startOffset, blo
 		return err
 	}
 
-	for i := 0; i < ctx.TotalShards; i++ {
+	for i := 0; i < ctx.Total(); i++ {
 		_, err := outputs[i].Write(buffers[i])
 		if err != nil {
 			return err
@@ -217,7 +217,7 @@ func encodeDatFile(remainingSize int64, baseFileName string, bufferSize int, lar
 		return fmt.Errorf("failed to create encoder: %w", err)
 	}
 
-	buffers := make([][]byte, ctx.TotalShards)
+	buffers := make([][]byte, ctx.Total())
 	for i := range buffers {
 		buffers[i] = make([]byte, bufferSize)
 	}
@@ -232,7 +232,7 @@ func encodeDatFile(remainingSize int64, baseFileName string, bufferSize int, lar
 	largeRowSize := largeBlockSize * int64(ctx.DataShards)
 	smallRowSize := smallBlockSize * int64(ctx.DataShards)
 
-	for remainingSize > largeRowSize {
+	for remainingSize >= largeRowSize {
 		err = encodeData(file, enc, processedSize, largeBlockSize, buffers, outputs, ctx)
 		if err != nil {
 			return fmt.Errorf("failed to encode large chunk data: %w", err)
@@ -258,7 +258,7 @@ func rebuildEcFiles(shardHasData []bool, inputFiles []*os.File, outputFiles []*o
 		return fmt.Errorf("failed to create encoder: %w", err)
 	}
 
-	buffers := make([][]byte, ctx.TotalShards)
+	buffers := make([][]byte, ctx.Total())
 	for i := range buffers {
 		if shardHasData[i] {
 			buffers[i] = make([]byte, ErasureCodingSmallBlockSize)
@@ -270,7 +270,7 @@ func rebuildEcFiles(shardHasData []bool, inputFiles []*os.File, outputFiles []*o
 	for {
 
 		// read the input data from files
-		for i := 0; i < ctx.TotalShards; i++ {
+		for i := 0; i < ctx.Total(); i++ {
 			if shardHasData[i] {
 				n, _ := inputFiles[i].ReadAt(buffers[i], startOffset)
 				if n == 0 {
@@ -294,7 +294,7 @@ func rebuildEcFiles(shardHasData []bool, inputFiles []*os.File, outputFiles []*o
 		}
 
 		// write the data to output files
-		for i := 0; i < ctx.TotalShards; i++ {
+		for i := 0; i < ctx.Total(); i++ {
 			if !shardHasData[i] {
 				n, _ := outputFiles[i].WriteAt(buffers[i][:inputBufferDataSize], startOffset)
 				if inputBufferDataSize != n {

weed/storage/erasure_coding/ec_test.go

@@ -188,7 +188,7 @@ func readFromFile(file *os.File, data []byte, ecFileOffset int64) (err error) {
 }
 
 func removeGeneratedFiles(baseFileName string, ctx *ECContext) {
-	for i := 0; i < ctx.TotalShards; i++ {
+	for i := 0; i < ctx.Total(); i++ {
 		fname := baseFileName + ctx.ToExt(i)
 		os.Remove(fname)
 	}

weed/storage/erasure_coding/ec_volume.go

@@ -74,14 +74,25 @@ func NewEcVolume(diskType types.DiskType, dir string, dirIdx string, collection
 		ev.Version = needle.Version(volumeInfo.Version)
 		ev.datFileSize = volumeInfo.DatFileSize
 		ev.ExpireAtSec = volumeInfo.ExpireAtSec
+		
+		// Initialize EC context from .vif if present; fallback to defaults
+		if volumeInfo.EcShardConfig != nil {
+			ev.ECContext = &ECContext{
+				Collection:   collection,
+				VolumeId:     vid,
+				DataShards:   int(volumeInfo.EcShardConfig.DataShards),
+				ParityShards: int(volumeInfo.EcShardConfig.ParityShards),
+			}
+			glog.V(1).Infof("Loaded EC config from VolumeInfo for volume %d: %s", vid, ev.ECContext.String())
+		} else {
+			ev.ECContext = NewDefaultECContext(collection, vid)
+		}
 	} else {
 		glog.Warningf("vif file not found,volumeId:%d, filename:%s", vid, dataBaseFileName)
 		volume_info.SaveVolumeInfo(dataBaseFileName+".vif", &volume_server_pb.VolumeInfo{Version: uint32(ev.Version)})
+		ev.ECContext = NewDefaultECContext(collection, vid)
 	}
 
-	// Initialize EC context with default configuration (Phase 1: always 10+4)
-	ev.ECContext = NewDefaultECContext(collection, vid)
-
 	ev.ShardLocations = make(map[ShardId][]pb.ServerAddress)
 
 	return