collect ec shard from multiple locations

fix https://github.com/seaweedfs/seaweedfs/issues/4365

weed/server/volume_grpc_erasure_coding.go

@@ -408,7 +408,9 @@ func (vs *VolumeServer) VolumeEcShardsToVolume(ctx context.Context, req *volume_
 
 	glog.V(0).Infof("VolumeEcShardsToVolume: %v", req)
 
-	v, found := vs.store.FindEcVolume(needle.VolumeId(req.VolumeId))
+	// collect .ec00 ~ .ec09 files
+	shardFileNames := make([]string, erasure_coding.DataShardsCount)
+	v, found := vs.store.CollectEcShards(needle.VolumeId(req.VolumeId), shardFileNames)
 	if !found {
 		return nil, fmt.Errorf("ec volume %d not found", req.VolumeId)
 	}
@@ -417,6 +419,12 @@ 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 < DataShardsCount; 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)
@@ -425,7 +433,7 @@ func (vs *VolumeServer) VolumeEcShardsToVolume(ctx context.Context, req *volume_
 	}
 
 	// write .dat file from .ec00 ~ .ec09 files
-	if err := erasure_coding.WriteDatFile(dataBaseFileName, datFileSize); err != nil {
+	if err := erasure_coding.WriteDatFile(dataBaseFileName, datFileSize, shardFileNames); err != nil {
 		return nil, fmt.Errorf("WriteDatFile %s: %v", dataBaseFileName, err)
 	}
 

weed/storage/disk_location_ec.go

@@ -38,6 +38,22 @@ func (l *DiskLocation) DestroyEcVolume(vid needle.VolumeId) {
 	}
 }
 
+func (l *DiskLocation) CollectEcShards(vid needle.VolumeId, shardFileNames []string) (ecVolume *erasure_coding.EcVolume, found bool) {
+	l.ecVolumesLock.RLock()
+	defer l.ecVolumesLock.RUnlock()
+
+	ecVolume, found = l.ecVolumes[vid]
+	if !found {
+		return
+	}
+	for _, ecShard := range ecVolume.Shards {
+		if ecShard.ShardId < erasure_coding.ShardId(len(shardFileNames)) {
+			shardFileNames[ecShard.ShardId] = erasure_coding.EcShardFileName(ecVolume.Collection, l.Directory, int(ecVolume.VolumeId)) + erasure_coding.ToExt(int(ecShard.ShardId))
+		}
+	}
+	return
+}
+
 func (l *DiskLocation) FindEcShard(vid needle.VolumeId, shardId erasure_coding.ShardId) (*erasure_coding.EcVolumeShard, bool) {
 	l.ecVolumesLock.RLock()
 	defer l.ecVolumesLock.RUnlock()

weed/storage/erasure_coding/ec_decoder.go

@@ -151,7 +151,7 @@ func iterateEcjFile(baseFileName string, processNeedleFn func(key types.NeedleId
 }
 
 // WriteDatFile generates .dat from from .ec00 ~ .ec09 files
-func WriteDatFile(baseFileName string, datFileSize int64) error {
+func WriteDatFile(baseFileName string, datFileSize int64, shardFileNames []string) error {
 
 	datFile, openErr := os.OpenFile(baseFileName+".dat", os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0644)
 	if openErr != nil {
@@ -161,13 +161,19 @@ func WriteDatFile(baseFileName string, datFileSize int64) error {
 
 	inputFiles := make([]*os.File, DataShardsCount)
 
+	defer func() {
 		for shardId := 0; shardId < DataShardsCount; shardId++ {
-		shardFileName := baseFileName + ToExt(shardId)
-		inputFiles[shardId], openErr = os.OpenFile(shardFileName, os.O_RDONLY, 0)
+			if inputFiles[shardId] != nil {
+				inputFiles[shardId].Close()
+			}
+		}
+	}()
+
+	for shardId := 0; shardId < DataShardsCount; shardId++ {
+		inputFiles[shardId], openErr = os.OpenFile(shardFileNames[shardId], os.O_RDONLY, 0)
 		if openErr != nil {
 			return openErr
 		}
-		defer inputFiles[shardId].Close()
 	}
 
 	for datFileSize >= DataShardsCount*ErasureCodingLargeBlockSize {

weed/storage/store_ec.go

@@ -116,6 +116,17 @@ func (s *Store) FindEcVolume(vid needle.VolumeId) (*erasure_coding.EcVolume, boo
 	return nil, false
 }
 
+// shardFiles is a list of shard files, which is used to return the shard locations
+func (s *Store) CollectEcShards(vid needle.VolumeId, shardFileNames []string) (ecVolume *erasure_coding.EcVolume, found bool) {
+	for _, location := range s.Locations {
+		if s, found := location.CollectEcShards(vid, shardFileNames); found {
+			ecVolume = s
+			found = true
+		}
+	}
+	return
+}
+
 func (s *Store) DestroyEcVolume(vid needle.VolumeId) {
 	for _, location := range s.Locations {
 		location.DestroyEcVolume(vid)