diff --git a/weed/filer2/filechunks.go b/weed/filer2/filechunks.go
index 0ac7bb43b..b248a8c59 100644
--- a/weed/filer2/filechunks.go
+++ b/weed/filer2/filechunks.go
@@ -1,6 +1,8 @@
 package filer2
 
 import (
+	"fmt"
+	"hash/fnv"
 	"math"
 	"sort"
 
@@ -17,6 +19,18 @@ func TotalSize(chunks []*filer_pb.FileChunk) (size uint64) {
 	return
 }
 
+func ETag(chunks []*filer_pb.FileChunk) (etag string) {
+	if len(chunks) == 1 {
+		return chunks[0].ETag
+	}
+
+	h := fnv.New32a()
+	for _, c := range chunks {
+		h.Write([]byte(c.ETag))
+	}
+	return fmt.Sprintf("%x", h.Sum32())
+}
+
 func CompactFileChunks(chunks []*filer_pb.FileChunk) (compacted, garbage []*filer_pb.FileChunk) {
 
 	visibles := nonOverlappingVisibleIntervals(chunks)
diff --git a/weed/filesys/dirty_page.go b/weed/filesys/dirty_page.go
index f4e47950e..145d89138 100644
--- a/weed/filesys/dirty_page.go
+++ b/weed/filesys/dirty_page.go
@@ -9,6 +9,7 @@ import (
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/operation"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"sync"
 )
 
 type ContinuousDirtyPages struct {
@@ -17,6 +18,7 @@ type ContinuousDirtyPages struct {
 	Size    int64
 	Data    []byte
 	f       *File
+	lock    sync.Mutex
 }
 
 func newDirtyPages(file *File) *ContinuousDirtyPages {
@@ -28,35 +30,14 @@ func newDirtyPages(file *File) *ContinuousDirtyPages {
 
 func (pages *ContinuousDirtyPages) AddPage(ctx context.Context, offset int64, data []byte) (chunks []*filer_pb.FileChunk, err error) {
 
+	pages.lock.Lock()
+	defer pages.lock.Unlock()
+
 	var chunk *filer_pb.FileChunk
 
 	if len(data) > len(pages.Data) {
 		// this is more than what buffer can hold.
-
-		// flush existing
-		if chunk, err = pages.saveExistingPagesToStorage(ctx); err == nil {
-			if chunk != nil {
-				glog.V(4).Infof("%s/%s flush existing [%d,%d)", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size))
-			}
-			chunks = append(chunks, chunk)
-		} else {
-			glog.V(0).Infof("%s/%s failed to flush1 [%d,%d): %v", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
-			return
-		}
-		pages.Size = 0
-
-		// flush the big page
-		if chunk, err = pages.saveToStorage(ctx, data, offset); err == nil {
-			if chunk != nil {
-				glog.V(4).Infof("%s/%s flush big request [%d,%d)", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size))
-				chunks = append(chunks, chunk)
-			}
-		} else {
-			glog.V(0).Infof("%s/%s failed to flush2 [%d,%d): %v", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
-			return
-		}
-
-		return
+		return pages.flushAndSave(ctx, offset, data)
 	}
 
 	if offset < pages.Offset || offset >= pages.Offset+int64(len(pages.Data)) ||
@@ -77,25 +58,74 @@ func (pages *ContinuousDirtyPages) AddPage(ctx context.Context, offset int64, da
 			return
 		}
 		pages.Offset = offset
-		pages.Size = int64(len(data))
 		copy(pages.Data, data)
+		pages.Size = int64(len(data))
 		return
 	}
 
-	copy(pages.Data[offset-pages.Offset:], data)
+	if offset != pages.Offset+pages.Size {
+		// when this happens, debug shows the data overlapping with existing data is empty
+		// the data is not just append
+		if offset == pages.Offset {
+			copy(pages.Data[pages.Size:], data[pages.Size:])
+		} else {
+			if pages.Size != 0 {
+				glog.V(0).Infof("possible error: pages [%d, %d) write [%d, %d)", pages.Offset, pages.Offset+pages.Size, offset, offset+int64(len(data)))
+			}
+			return pages.flushAndSave(ctx, offset, data)
+		}
+	} else {
+		copy(pages.Data[offset-pages.Offset:], data)
+	}
+
 	pages.Size = max(pages.Size, offset+int64(len(data))-pages.Offset)
 
 	return
 }
 
+func (pages *ContinuousDirtyPages) flushAndSave(ctx context.Context, offset int64, data []byte) (chunks []*filer_pb.FileChunk, err error) {
+
+	var chunk *filer_pb.FileChunk
+
+	// flush existing
+	if chunk, err = pages.saveExistingPagesToStorage(ctx); err == nil {
+		if chunk != nil {
+			glog.V(4).Infof("%s/%s flush existing [%d,%d)", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size))
+			chunks = append(chunks, chunk)
+		}
+	} else {
+		glog.V(0).Infof("%s/%s failed to flush1 [%d,%d): %v", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
+		return
+	}
+	pages.Size = 0
+	pages.Offset = 0
+
+	// flush the new page
+	if chunk, err = pages.saveToStorage(ctx, data, offset); err == nil {
+		if chunk != nil {
+			glog.V(4).Infof("%s/%s flush big request [%d,%d)", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size))
+			chunks = append(chunks, chunk)
+		}
+	} else {
+		glog.V(0).Infof("%s/%s failed to flush2 [%d,%d): %v", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
+		return
+	}
+
+	return
+}
+
 func (pages *ContinuousDirtyPages) FlushToStorage(ctx context.Context) (chunk *filer_pb.FileChunk, err error) {
 
+	pages.lock.Lock()
+	defer pages.lock.Unlock()
+
 	if pages.Size == 0 {
 		return nil, nil
 	}
 
 	if chunk, err = pages.saveExistingPagesToStorage(ctx); err == nil {
 		pages.Size = 0
+		pages.Offset = 0
 		if chunk != nil {
 			glog.V(4).Infof("%s/%s flush [%d,%d)", pages.f.dir.Path, pages.f.Name, chunk.Offset, chunk.Offset+int64(chunk.Size))
 		}
@@ -104,15 +134,16 @@ func (pages *ContinuousDirtyPages) FlushToStorage(ctx context.Context) (chunk *f
 }
 
 func (pages *ContinuousDirtyPages) saveExistingPagesToStorage(ctx context.Context) (*filer_pb.FileChunk, error) {
-	return pages.saveToStorage(ctx, pages.Data[:pages.Size], pages.Offset)
-}
-
-func (pages *ContinuousDirtyPages) saveToStorage(ctx context.Context, buf []byte, offset int64) (*filer_pb.FileChunk, error) {
 
 	if pages.Size == 0 {
 		return nil, nil
 	}
 
+	return pages.saveToStorage(ctx, pages.Data[:pages.Size], pages.Offset)
+}
+
+func (pages *ContinuousDirtyPages) saveToStorage(ctx context.Context, buf []byte, offset int64) (*filer_pb.FileChunk, error) {
+
 	var fileId, host string
 
 	if err := pages.f.wfs.withFilerClient(func(client filer_pb.SeaweedFilerClient) error {
diff --git a/weed/filesys/filehandle.go b/weed/filesys/filehandle.go
index 0c13db984..786abbef2 100644
--- a/weed/filesys/filehandle.go
+++ b/weed/filesys/filehandle.go
@@ -140,6 +140,7 @@ func (fh *FileHandle) Write(ctx context.Context, req *fuse.WriteRequest, resp *f
 
 	chunks, err := fh.dirtyPages.AddPage(ctx, req.Offset, req.Data)
 	if err != nil {
+		glog.Errorf("%+v/%v write fh %d: [%d,%d): %v", fh.f.dir.Path, fh.f.Name, fh.handle, req.Offset, req.Offset+int64(len(req.Data)), err)
 		return fmt.Errorf("write %s/%s at [%d,%d): %v", fh.f.dir.Path, fh.f.Name, req.Offset, req.Offset+int64(len(req.Data)), err)
 	}
 
@@ -179,7 +180,7 @@ func (fh *FileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) error {
 
 	chunk, err := fh.dirtyPages.FlushToStorage(ctx)
 	if err != nil {
-		glog.V(0).Infof("flush %s/%s to %s [%d,%d): %v", fh.f.dir.Path, fh.f.Name, chunk.FileId, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
+		glog.Errorf("flush %s/%s to %s [%d,%d): %v", fh.f.dir.Path, fh.f.Name, chunk.FileId, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
 		return fmt.Errorf("flush %s/%s to %s [%d,%d): %v", fh.f.dir.Path, fh.f.Name, chunk.FileId, chunk.Offset, chunk.Offset+int64(chunk.Size), err)
 	}
 	if chunk != nil {
@@ -200,6 +201,8 @@ func (fh *FileHandle) Flush(ctx context.Context, req *fuse.FlushRequest) error {
 
 		if fh.f.attributes != nil {
 			fh.f.attributes.Mime = fh.contentType
+			fh.f.attributes.Uid = req.Uid
+			fh.f.attributes.Gid = req.Gid
 		}
 
 		request := &filer_pb.UpdateEntryRequest{
diff --git a/weed/pb/filer.proto b/weed/pb/filer.proto
index 7681c6c5e..e2b175c11 100644
--- a/weed/pb/filer.proto
+++ b/weed/pb/filer.proto
@@ -63,7 +63,7 @@ message Entry {
     bool is_directory = 2;
     repeated FileChunk chunks = 3;
     FuseAttributes attributes = 4;
-    map<string, string> extended = 5;
+    map<string, bytes> extended = 5;
 }
 
 message EventNotification {
@@ -76,6 +76,7 @@ message FileChunk {
     int64 offset = 2;
     uint64 size = 3;
     int64 mtime = 4;
+    string e_tag = 5;
 }
 
 message FuseAttributes {
@@ -100,6 +101,7 @@ message GetEntryAttributesRequest {
 message GetEntryAttributesResponse {
     FuseAttributes attributes = 1;
     repeated FileChunk chunks = 2;
+    map<string, bytes> extended = 3;
 }
 
 message GetFileContentRequest {
diff --git a/weed/pb/filer_pb/filer.pb.go b/weed/pb/filer_pb/filer.pb.go
index 70d63957b..7ee8a7dd2 100644
--- a/weed/pb/filer_pb/filer.pb.go
+++ b/weed/pb/filer_pb/filer.pb.go
@@ -167,7 +167,7 @@ type Entry struct {
 	IsDirectory bool              `protobuf:"varint,2,opt,name=is_directory,json=isDirectory" json:"is_directory,omitempty"`
 	Chunks      []*FileChunk      `protobuf:"bytes,3,rep,name=chunks" json:"chunks,omitempty"`
 	Attributes  *FuseAttributes   `protobuf:"bytes,4,opt,name=attributes" json:"attributes,omitempty"`
-	Extended    map[string]string `protobuf:"bytes,5,rep,name=extended" json:"extended,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value"`
+	Extended    map[string][]byte `protobuf:"bytes,5,rep,name=extended" json:"extended,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value,proto3"`
 }
 
 func (m *Entry) Reset()                    { *m = Entry{} }
@@ -203,7 +203,7 @@ func (m *Entry) GetAttributes() *FuseAttributes {
 	return nil
 }
 
-func (m *Entry) GetExtended() map[string]string {
+func (m *Entry) GetExtended() map[string][]byte {
 	if m != nil {
 		return m.Extended
 	}
@@ -239,6 +239,7 @@ type FileChunk struct {
 	Offset int64  `protobuf:"varint,2,opt,name=offset" json:"offset,omitempty"`
 	Size   uint64 `protobuf:"varint,3,opt,name=size" json:"size,omitempty"`
 	Mtime  int64  `protobuf:"varint,4,opt,name=mtime" json:"mtime,omitempty"`
+	ETag   string `protobuf:"bytes,5,opt,name=e_tag,json=eTag" json:"e_tag,omitempty"`
 }
 
 func (m *FileChunk) Reset()                    { *m = FileChunk{} }
@@ -274,6 +275,13 @@ func (m *FileChunk) GetMtime() int64 {
 	return 0
 }
 
+func (m *FileChunk) GetETag() string {
+	if m != nil {
+		return m.ETag
+	}
+	return ""
+}
+
 type FuseAttributes struct {
 	FileSize    uint64 `protobuf:"varint,1,opt,name=file_size,json=fileSize" json:"file_size,omitempty"`
 	Mtime       int64  `protobuf:"varint,2,opt,name=mtime" json:"mtime,omitempty"`
@@ -395,8 +403,9 @@ func (m *GetEntryAttributesRequest) GetFileId() string {
 }
 
 type GetEntryAttributesResponse struct {
-	Attributes *FuseAttributes `protobuf:"bytes,1,opt,name=attributes" json:"attributes,omitempty"`
-	Chunks     []*FileChunk    `protobuf:"bytes,2,rep,name=chunks" json:"chunks,omitempty"`
+	Attributes *FuseAttributes   `protobuf:"bytes,1,opt,name=attributes" json:"attributes,omitempty"`
+	Chunks     []*FileChunk      `protobuf:"bytes,2,rep,name=chunks" json:"chunks,omitempty"`
+	Extended   map[string][]byte `protobuf:"bytes,3,rep,name=extended" json:"extended,omitempty" protobuf_key:"bytes,1,opt,name=key" protobuf_val:"bytes,2,opt,name=value,proto3"`
 }
 
 func (m *GetEntryAttributesResponse) Reset()                    { *m = GetEntryAttributesResponse{} }
@@ -418,6 +427,13 @@ func (m *GetEntryAttributesResponse) GetChunks() []*FileChunk {
 	return nil
 }
 
+func (m *GetEntryAttributesResponse) GetExtended() map[string][]byte {
+	if m != nil {
+		return m.Extended
+	}
+	return nil
+}
+
 type GetFileContentRequest struct {
 	FileId string `protobuf:"bytes,1,opt,name=file_id,json=fileId" json:"file_id,omitempty"`
 }
@@ -1122,80 +1138,82 @@ var _SeaweedFiler_serviceDesc = grpc.ServiceDesc{
 func init() { proto.RegisterFile("filer.proto", fileDescriptor0) }
 
 var fileDescriptor0 = []byte{
-	// 1187 bytes of a gzipped FileDescriptorProto
-	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xb4, 0x57, 0xcd, 0x6e, 0xdb, 0x46,
-	0x10, 0x36, 0x49, 0x4b, 0x16, 0x47, 0x72, 0x1a, 0xaf, 0x9d, 0x84, 0x55, 0xec, 0x54, 0x61, 0x93,
-	0xc2, 0x41, 0x0d, 0xc3, 0x70, 0x7b, 0x48, 0x1a, 0x14, 0x68, 0x60, 0x3b, 0x41, 0x00, 0x27, 0x01,
-	0xe8, 0xba, 0x40, 0xd1, 0x83, 0x40, 0x93, 0x23, 0x77, 0x61, 0x8a, 0x54, 0xc9, 0xa5, 0x1c, 0xf7,
-	0xda, 0x63, 0x4f, 0x7d, 0x80, 0x9e, 0x7b, 0xef, 0x03, 0xf4, 0xd2, 0x17, 0x2b, 0xf6, 0x87, 0xd4,
-	0x52, 0xa4, 0x9c, 0xfa, 0x90, 0xdb, 0xee, 0xcc, 0xec, 0xcc, 0x7c, 0xb3, 0x33, 0xdf, 0x92, 0xd0,
-	0x1d, 0xd1, 0x08, 0xd3, 0xdd, 0x49, 0x9a, 0xb0, 0x84, 0x74, 0xc4, 0x66, 0x38, 0x39, 0x73, 0xdf,
-	0xc1, 0xfd, 0xe3, 0x24, 0xb9, 0xc8, 0x27, 0x87, 0x34, 0xc5, 0x80, 0x25, 0xe9, 0xd5, 0x51, 0xcc,
-	0xd2, 0x2b, 0x0f, 0x7f, 0xc9, 0x31, 0x63, 0x64, 0x13, 0xec, 0xb0, 0x50, 0x38, 0xc6, 0xc0, 0xd8,
-	0xb6, 0xbd, 0x99, 0x80, 0x10, 0x58, 0x8e, 0xfd, 0x31, 0x3a, 0xa6, 0x50, 0x88, 0xb5, 0x7b, 0x04,
-	0x9b, 0xcd, 0x0e, 0xb3, 0x49, 0x12, 0x67, 0x48, 0x1e, 0x43, 0x0b, 0xb9, 0x40, 0x78, 0xeb, 0xee,
-	0x7f, 0xb2, 0x5b, 0xa4, 0xb2, 0x2b, 0xed, 0xa4, 0xd6, 0xfd, 0xc7, 0x00, 0x72, 0x4c, 0x33, 0xc6,
-	0x85, 0x14, 0xb3, 0xff, 0x97, 0xcf, 0x5d, 0x68, 0x4f, 0x52, 0x1c, 0xd1, 0xf7, 0x2a, 0x23, 0xb5,
-	0x23, 0x3b, 0xb0, 0x96, 0x31, 0x3f, 0x65, 0x2f, 0xd3, 0x64, 0xfc, 0x92, 0x46, 0xf8, 0x96, 0x27,
-	0x6d, 0x09, 0x93, 0xba, 0x82, 0xec, 0x02, 0xa1, 0x71, 0x10, 0xe5, 0x19, 0x9d, 0xe2, 0x49, 0xa1,
-	0x75, 0x96, 0x07, 0xc6, 0x76, 0xc7, 0x6b, 0xd0, 0x90, 0x0d, 0x68, 0x45, 0x74, 0x4c, 0x99, 0xd3,
-	0x1a, 0x18, 0xdb, 0xab, 0x9e, 0xdc, 0xb8, 0xdf, 0xc1, 0x7a, 0x25, 0x7f, 0x05, 0xff, 0x09, 0xac,
-	0xa0, 0x14, 0x39, 0xc6, 0xc0, 0x6a, 0x2a, 0x40, 0xa1, 0x77, 0xff, 0x34, 0xa1, 0x25, 0x44, 0x65,
-	0x9d, 0x8d, 0x59, 0x9d, 0xc9, 0x43, 0xe8, 0xd1, 0x6c, 0x38, 0x2b, 0x86, 0x29, 0xf2, 0xeb, 0xd2,
-	0xac, 0xac, 0x3b, 0xf9, 0x12, 0xda, 0xc1, 0xcf, 0x79, 0x7c, 0x91, 0x39, 0x96, 0x08, 0xb5, 0x3e,
-	0x0b, 0xc5, 0xc1, 0x1e, 0x70, 0x9d, 0xa7, 0x4c, 0xc8, 0x53, 0x00, 0x9f, 0xb1, 0x94, 0x9e, 0xe5,
-	0x0c, 0x33, 0x81, 0xb6, 0xbb, 0xef, 0x68, 0x07, 0xf2, 0x0c, 0x5f, 0x94, 0x7a, 0x4f, 0xb3, 0x25,
-	0xcf, 0xa0, 0x83, 0xef, 0x19, 0xc6, 0x21, 0x86, 0x4e, 0x4b, 0x04, 0xda, 0x9a, 0xc3, 0xb4, 0x7b,
-	0xa4, 0xf4, 0x12, 0x61, 0x69, 0xde, 0x7f, 0x0e, 0xab, 0x15, 0x15, 0xb9, 0x0d, 0xd6, 0x05, 0x16,
-	0x37, 0xcb, 0x97, 0xbc, 0xba, 0x53, 0x3f, 0xca, 0x8b, 0x26, 0x93, 0x9b, 0x6f, 0xcc, 0xa7, 0x86,
-	0x9b, 0xc0, 0xda, 0xd1, 0x14, 0x63, 0xf6, 0x36, 0x61, 0x74, 0x44, 0x03, 0x9f, 0xd1, 0x24, 0x26,
-	0x3b, 0x60, 0x27, 0x51, 0x38, 0x94, 0x2d, 0x66, 0x36, 0xb7, 0x58, 0x27, 0x89, 0x54, 0xb8, 0x1d,
-	0xb0, 0x63, 0xbc, 0x54, 0xd6, 0xd6, 0x02, 0xeb, 0x18, 0x2f, 0xc5, 0xca, 0x1d, 0x81, 0x5d, 0xd6,
-	0x8d, 0xdc, 0x83, 0x15, 0x6e, 0x38, 0xa4, 0xa1, 0xca, 0xb6, 0xcd, 0xb7, 0xaf, 0x43, 0xde, 0x84,
-	0xc9, 0x68, 0x94, 0x21, 0x13, 0xe1, 0x2d, 0x4f, 0xed, 0xf8, 0x25, 0x66, 0xf4, 0x57, 0xd9, 0x77,
-	0xcb, 0x9e, 0x58, 0x73, 0x70, 0x63, 0x46, 0xc7, 0x28, 0xea, 0x6d, 0x79, 0x72, 0xe3, 0xfe, 0x6e,
-	0xc2, 0xad, 0x6a, 0xbd, 0xc9, 0x7d, 0xb0, 0x45, 0x34, 0xe1, 0xc1, 0x10, 0x1e, 0xc4, 0x0c, 0x9f,
-	0x54, 0xbc, 0x98, 0x9a, 0x97, 0xf2, 0xc8, 0x38, 0x09, 0x65, 0xd0, 0x55, 0x79, 0xe4, 0x4d, 0x12,
-	0x22, 0xaf, 0x73, 0x4e, 0x43, 0x11, 0x76, 0xd5, 0xe3, 0x4b, 0x2e, 0x39, 0xa7, 0xa1, 0xea, 0x61,
-	0xbe, 0xe4, 0x40, 0x82, 0x54, 0xf8, 0x6d, 0x4b, 0x20, 0x72, 0xc7, 0x81, 0x8c, 0xb9, 0x74, 0x45,
-	0x76, 0x23, 0x5f, 0x93, 0x01, 0x74, 0x53, 0x9c, 0x44, 0xea, 0x16, 0x9c, 0x8e, 0x50, 0xe9, 0x22,
-	0xf2, 0x00, 0x20, 0x48, 0xa2, 0x08, 0x03, 0x61, 0x60, 0x0b, 0x03, 0x4d, 0xc2, 0xeb, 0xc9, 0x58,
-	0x34, 0xcc, 0x30, 0x70, 0x60, 0x60, 0x6c, 0xb7, 0xbc, 0x36, 0x63, 0xd1, 0x09, 0x06, 0xee, 0x39,
-	0x7c, 0xfa, 0x0a, 0xc5, 0x1c, 0x5d, 0x69, 0x0d, 0xa8, 0xf8, 0xa0, 0x69, 0x32, 0xb6, 0x00, 0x26,
-	0x7e, 0x8a, 0x31, 0xe3, 0xd3, 0xa1, 0xda, 0xc6, 0x96, 0x92, 0x43, 0x9a, 0xea, 0x17, 0x67, 0xe9,
-	0x17, 0xe7, 0xfe, 0x66, 0x40, 0xbf, 0x29, 0x92, 0x9a, 0xdc, 0xea, 0x80, 0x18, 0x37, 0x18, 0x90,
-	0xd9, 0x1c, 0x9a, 0x1f, 0x9c, 0x43, 0x77, 0x0f, 0xee, 0xbc, 0x42, 0x26, 0xe4, 0x49, 0xcc, 0x30,
-	0x66, 0x05, 0xd4, 0x45, 0x0d, 0xe7, 0xee, 0xc3, 0xdd, 0xf9, 0x13, 0x2a, 0x65, 0x07, 0x56, 0x02,
-	0x29, 0x12, 0x47, 0x7a, 0x5e, 0xb1, 0x75, 0x7f, 0x04, 0x72, 0x90, 0xa2, 0xcf, 0xf0, 0x06, 0x6c,
-	0x5f, 0x32, 0xb7, 0x79, 0x2d, 0x73, 0xdf, 0x81, 0xf5, 0x8a, 0x6b, 0x99, 0x0b, 0x8f, 0x78, 0x3a,
-	0x09, 0x3f, 0x56, 0xc4, 0x8a, 0x6b, 0x15, 0xf1, 0x6f, 0x03, 0xc8, 0x21, 0x46, 0x78, 0xa3, 0x90,
-	0x0d, 0x4f, 0x5a, 0x8d, 0x6a, 0xad, 0x3a, 0xd5, 0x3e, 0x82, 0x5b, 0xdc, 0x44, 0x44, 0x1b, 0x86,
-	0x3e, 0xf3, 0xd5, 0x7b, 0xd1, 0xa3, 0x99, 0x4c, 0xe1, 0xd0, 0x67, 0xbe, 0x72, 0x94, 0x62, 0x90,
-	0xa7, 0xfc, 0x09, 0x11, 0xc3, 0x26, 0x1c, 0x79, 0x85, 0x88, 0x63, 0xa9, 0xe4, 0xac, 0xb0, 0xfc,
-	0x65, 0xc0, 0xfa, 0x8b, 0x2c, 0xa3, 0xe7, 0xf1, 0x0f, 0x49, 0x94, 0x8f, 0xb1, 0x00, 0xb3, 0x01,
-	0xad, 0x20, 0xc9, 0xd5, 0xfd, 0xb6, 0x3c, 0xb9, 0x99, 0x9b, 0x35, 0xb3, 0x36, 0x6b, 0x73, 0xd3,
-	0x6a, 0xd5, 0xa7, 0x55, 0x9b, 0xc6, 0x65, 0x7d, 0x1a, 0xc9, 0x67, 0xd0, 0xe5, 0xf0, 0x86, 0x01,
-	0xc6, 0x0c, 0x53, 0x81, 0xc0, 0xf6, 0x80, 0x8b, 0x0e, 0x84, 0xc4, 0x9d, 0xc2, 0x46, 0x35, 0x51,
-	0xd5, 0x8b, 0x0b, 0xf9, 0x92, 0x53, 0x51, 0x1a, 0xa9, 0x2c, 0xf9, 0x52, 0x0c, 0x70, 0x7e, 0x16,
-	0xd1, 0x60, 0xc8, 0x15, 0x96, 0x1a, 0x60, 0x21, 0x39, 0x4d, 0xa3, 0x19, 0xe6, 0x65, 0x0d, 0xb3,
-	0xfb, 0x35, 0xac, 0xcb, 0xef, 0x8e, 0x6a, 0x81, 0xb6, 0x00, 0xa6, 0x42, 0x30, 0xa4, 0xa1, 0x7c,
-	0x72, 0x6d, 0xcf, 0x96, 0x92, 0xd7, 0x61, 0xe6, 0x7e, 0x0b, 0xf6, 0x71, 0x22, 0x31, 0x67, 0x64,
-	0x0f, 0xec, 0xa8, 0xd8, 0xa8, 0xd7, 0x99, 0xcc, 0x5a, 0xae, 0xb0, 0xf3, 0x66, 0x46, 0xee, 0x73,
-	0xe8, 0x14, 0xe2, 0x02, 0x87, 0xb1, 0x08, 0x87, 0x39, 0x87, 0xc3, 0xfd, 0xd7, 0x80, 0x8d, 0x6a,
-	0xca, 0xaa, 0x54, 0xa7, 0xb0, 0x5a, 0x86, 0x18, 0x8e, 0xfd, 0x89, 0xca, 0x65, 0x4f, 0xcf, 0xa5,
-	0x7e, 0xac, 0x4c, 0x30, 0x7b, 0xe3, 0x4f, 0x64, 0xf7, 0xf4, 0x22, 0x4d, 0xd4, 0xff, 0x1e, 0xd6,
-	0x6a, 0x26, 0x0d, 0x0f, 0xee, 0x13, 0xfd, 0xc1, 0xad, 0x90, 0x55, 0x79, 0x5a, 0x7f, 0x85, 0x9f,
-	0xc1, 0x3d, 0xd9, 0xb0, 0x07, 0x65, 0x7f, 0x15, 0xb5, 0xaf, 0xb6, 0xa1, 0x31, 0xdf, 0x86, 0x6e,
-	0x1f, 0x9c, 0xfa, 0x51, 0x09, 0x66, 0xff, 0x8f, 0x36, 0xf4, 0x4e, 0xd0, 0xbf, 0x44, 0x0c, 0x39,
-	0xb3, 0xa5, 0xe4, 0xbc, 0x28, 0x56, 0xf5, 0xbb, 0x92, 0x3c, 0x9e, 0xaf, 0x4a, 0xe3, 0x87, 0x6c,
-	0xff, 0x8b, 0x0f, 0x99, 0xa9, 0x41, 0x5b, 0x22, 0xc7, 0xd0, 0xd5, 0x3e, 0xdc, 0xc8, 0xa6, 0x76,
-	0xb0, 0xf6, 0x3d, 0xda, 0xdf, 0x5a, 0xa0, 0x2d, 0xbd, 0xf9, 0x40, 0xea, 0x6f, 0x0a, 0xf9, 0x7c,
-	0x76, 0x6c, 0xe1, 0xdb, 0xd6, 0x7f, 0x74, 0xbd, 0x91, 0x9e, 0xb0, 0x46, 0xb8, 0x7a, 0xc2, 0x75,
-	0x8a, 0xd7, 0x13, 0x6e, 0x62, 0x69, 0xe1, 0x4d, 0x23, 0x53, 0xdd, 0x5b, 0x9d, 0xbe, 0x75, 0x6f,
-	0x4d, 0x0c, 0x2c, 0xbc, 0x69, 0x74, 0xa6, 0x7b, 0xab, 0x33, 0xb3, 0xee, 0xad, 0x89, 0x03, 0x97,
-	0xc8, 0x3b, 0xe8, 0xe9, 0xdc, 0x42, 0xb4, 0x03, 0x0d, 0xe4, 0xd8, 0x7f, 0xb0, 0x48, 0xad, 0x3b,
-	0xd4, 0x47, 0x49, 0x77, 0xd8, 0x40, 0x26, 0xba, 0xc3, 0xa6, 0x09, 0x74, 0x97, 0xc8, 0x4f, 0x70,
-	0x7b, 0xbe, 0xa5, 0xc9, 0xc3, 0x79, 0x58, 0xb5, 0x49, 0xe9, 0xbb, 0xd7, 0x99, 0x14, 0xce, 0xcf,
-	0xda, 0xe2, 0xe7, 0xed, 0xab, 0xff, 0x02, 0x00, 0x00, 0xff, 0xff, 0x8a, 0x18, 0xac, 0xec, 0xcb,
-	0x0d, 0x00, 0x00,
+	// 1218 bytes of a gzipped FileDescriptorProto
+	0x1f, 0x8b, 0x08, 0x00, 0x00, 0x09, 0x6e, 0x88, 0x02, 0xff, 0xb4, 0x57, 0xcd, 0x6e, 0xdb, 0xc6,
+	0x13, 0x37, 0xa9, 0x0f, 0x8b, 0x23, 0x39, 0xff, 0x78, 0xe5, 0x24, 0xfc, 0x2b, 0x76, 0xaa, 0xb0,
+	0x49, 0xe1, 0xa0, 0x86, 0x61, 0xb8, 0x3d, 0x24, 0x0d, 0x0a, 0x34, 0xb0, 0x9d, 0x20, 0x80, 0xe3,
+	0x00, 0x74, 0x5c, 0xa0, 0xe8, 0x41, 0xa0, 0xc9, 0xb1, 0xba, 0x30, 0x45, 0xaa, 0xe4, 0xd2, 0x8e,
+	0xdb, 0x47, 0xe8, 0xa5, 0x7d, 0x80, 0x9e, 0x7b, 0xef, 0x03, 0xf4, 0xd2, 0x17, 0x2b, 0xf6, 0x83,
+	0xd4, 0x52, 0xa4, 0x9c, 0xf8, 0x90, 0xdb, 0xee, 0xcc, 0xec, 0xcc, 0x6f, 0x86, 0x33, 0xbf, 0x5d,
+	0x42, 0xf7, 0x8c, 0x86, 0x98, 0x6c, 0x4f, 0x93, 0x98, 0xc5, 0xa4, 0x23, 0x36, 0xa3, 0xe9, 0xa9,
+	0xf3, 0x16, 0xee, 0x1f, 0xc6, 0xf1, 0x79, 0x36, 0xdd, 0xa7, 0x09, 0xfa, 0x2c, 0x4e, 0xae, 0x0e,
+	0x22, 0x96, 0x5c, 0xb9, 0xf8, 0x73, 0x86, 0x29, 0x23, 0xeb, 0x60, 0x05, 0xb9, 0xc2, 0x36, 0x86,
+	0xc6, 0xa6, 0xe5, 0xce, 0x04, 0x84, 0x40, 0x33, 0xf2, 0x26, 0x68, 0x9b, 0x42, 0x21, 0xd6, 0xce,
+	0x01, 0xac, 0xd7, 0x3b, 0x4c, 0xa7, 0x71, 0x94, 0x22, 0x79, 0x0c, 0x2d, 0xe4, 0x02, 0xe1, 0xad,
+	0xbb, 0xfb, 0xbf, 0xed, 0x1c, 0xca, 0xb6, 0xb4, 0x93, 0x5a, 0xe7, 0x1f, 0x03, 0xc8, 0x21, 0x4d,
+	0x19, 0x17, 0x52, 0x4c, 0x3f, 0x0e, 0xcf, 0x5d, 0x68, 0x4f, 0x13, 0x3c, 0xa3, 0xef, 0x15, 0x22,
+	0xb5, 0x23, 0x5b, 0xb0, 0x9a, 0x32, 0x2f, 0x61, 0x2f, 0x93, 0x78, 0xf2, 0x92, 0x86, 0x78, 0xc4,
+	0x41, 0x37, 0x84, 0x49, 0x55, 0x41, 0xb6, 0x81, 0xd0, 0xc8, 0x0f, 0xb3, 0x94, 0x5e, 0xe0, 0x71,
+	0xae, 0xb5, 0x9b, 0x43, 0x63, 0xb3, 0xe3, 0xd6, 0x68, 0xc8, 0x1a, 0xb4, 0x42, 0x3a, 0xa1, 0xcc,
+	0x6e, 0x0d, 0x8d, 0xcd, 0x15, 0x57, 0x6e, 0x9c, 0xef, 0xa0, 0x5f, 0xc2, 0xaf, 0xd2, 0x7f, 0x02,
+	0xcb, 0x28, 0x45, 0xb6, 0x31, 0x6c, 0xd4, 0x15, 0x20, 0xd7, 0x3b, 0x7f, 0x9a, 0xd0, 0x12, 0xa2,
+	0xa2, 0xce, 0xc6, 0xac, 0xce, 0xe4, 0x21, 0xf4, 0x68, 0x3a, 0x9a, 0x15, 0xc3, 0x14, 0xf8, 0xba,
+	0x34, 0x2d, 0xea, 0x4e, 0xbe, 0x84, 0xb6, 0xff, 0x53, 0x16, 0x9d, 0xa7, 0x76, 0x43, 0x84, 0xea,
+	0xcf, 0x42, 0xf1, 0x64, 0xf7, 0xb8, 0xce, 0x55, 0x26, 0xe4, 0x29, 0x80, 0xc7, 0x58, 0x42, 0x4f,
+	0x33, 0x86, 0xa9, 0xc8, 0xb6, 0xbb, 0x6b, 0x6b, 0x07, 0xb2, 0x14, 0x5f, 0x14, 0x7a, 0x57, 0xb3,
+	0x25, 0xcf, 0xa0, 0x83, 0xef, 0x19, 0x46, 0x01, 0x06, 0x76, 0x4b, 0x04, 0xda, 0x98, 0xcb, 0x69,
+	0xfb, 0x40, 0xe9, 0x65, 0x86, 0x85, 0xf9, 0xe0, 0x39, 0xac, 0x94, 0x54, 0xe4, 0x36, 0x34, 0xce,
+	0x31, 0xff, 0xb2, 0x7c, 0xc9, 0xab, 0x7b, 0xe1, 0x85, 0x99, 0x6c, 0xb2, 0x9e, 0x2b, 0x37, 0xdf,
+	0x98, 0x4f, 0x0d, 0x27, 0x86, 0xd5, 0x83, 0x0b, 0x8c, 0xd8, 0x51, 0xcc, 0xe8, 0x19, 0xf5, 0x3d,
+	0x46, 0xe3, 0x88, 0x6c, 0x81, 0x15, 0x87, 0xc1, 0x48, 0xb6, 0x98, 0x59, 0xdf, 0x62, 0x9d, 0x38,
+	0x54, 0xe1, 0xb6, 0xc0, 0x8a, 0xf0, 0x52, 0x59, 0x37, 0x16, 0x58, 0x47, 0x78, 0x29, 0x56, 0xce,
+	0xaf, 0x60, 0x15, 0x75, 0x23, 0xf7, 0x60, 0x99, 0x1b, 0x8e, 0x68, 0xa0, 0xd0, 0xb6, 0xf9, 0xf6,
+	0x75, 0xc0, 0x9b, 0x30, 0x3e, 0x3b, 0x4b, 0x91, 0x89, 0xf0, 0x0d, 0x57, 0xed, 0xf8, 0x47, 0x4c,
+	0xe9, 0x2f, 0xb2, 0xef, 0x9a, 0xae, 0x58, 0xf3, 0xe4, 0x26, 0x8c, 0x4e, 0x50, 0xd4, 0xbb, 0xe1,
+	0xca, 0x0d, 0xe9, 0x43, 0x0b, 0x47, 0xcc, 0x1b, 0x8b, 0x86, 0xb2, 0xdc, 0x26, 0xbe, 0xf3, 0xc6,
+	0xce, 0x6f, 0x26, 0xdc, 0x2a, 0x7f, 0x04, 0x72, 0x1f, 0x2c, 0x01, 0x41, 0xb8, 0x35, 0x84, 0x5b,
+	0x31, 0xd8, 0xc7, 0x25, 0xd7, 0xa6, 0xee, 0x3a, 0x3f, 0x32, 0x89, 0x03, 0x89, 0x64, 0x45, 0x1e,
+	0x79, 0x13, 0x07, 0xc8, 0x8b, 0x9f, 0xd1, 0x40, 0x60, 0x59, 0x71, 0xf9, 0x92, 0x4b, 0xc6, 0x34,
+	0x50, 0x8d, 0xcd, 0x97, 0x3c, 0x3b, 0x3f, 0x11, 0x7e, 0xdb, 0x32, 0x3b, 0xb9, 0xe3, 0xd9, 0x4d,
+	0xb8, 0x74, 0x59, 0x42, 0xe6, 0x6b, 0x32, 0x84, 0x6e, 0x82, 0xd3, 0x50, 0x7d, 0x1a, 0xbb, 0x23,
+	0x54, 0xba, 0x88, 0x3c, 0x00, 0xf0, 0xe3, 0x30, 0x44, 0x5f, 0x18, 0x58, 0xc2, 0x40, 0x93, 0xf0,
+	0x22, 0x33, 0x16, 0x8e, 0x52, 0xf4, 0x6d, 0x18, 0x1a, 0x9b, 0x2d, 0xb7, 0xcd, 0x58, 0x78, 0x8c,
+	0xbe, 0x33, 0x86, 0xff, 0xbf, 0x42, 0x31, 0x5c, 0x57, 0x5a, 0x57, 0x2a, 0x92, 0xa8, 0x1b, 0x97,
+	0x0d, 0x80, 0xa9, 0x97, 0x60, 0xc4, 0xf8, 0xc8, 0x28, 0x7a, 0xb0, 0xa4, 0x64, 0x9f, 0x26, 0xfa,
+	0xd7, 0x6c, 0xe8, 0x5f, 0xd3, 0xf9, 0xdd, 0x84, 0x41, 0x5d, 0x24, 0x35, 0xce, 0xe5, 0xa9, 0x31,
+	0x6e, 0x30, 0x35, 0xb3, 0xe1, 0x34, 0x3f, 0x3c, 0x9c, 0x47, 0xda, 0x88, 0xc9, 0x59, 0xde, 0x9d,
+	0x99, 0x2f, 0x86, 0xf7, 0x69, 0xe6, 0x6e, 0x07, 0xee, 0xbc, 0x42, 0x26, 0x40, 0xc6, 0x11, 0xc3,
+	0x88, 0xe5, 0x75, 0x5f, 0x34, 0x12, 0xce, 0x2e, 0xdc, 0x9d, 0x3f, 0xa1, 0xea, 0x67, 0xc3, 0xb2,
+	0x2f, 0x45, 0xe2, 0x48, 0xcf, 0xcd, 0xb7, 0xce, 0x0f, 0x40, 0xf6, 0x12, 0xf4, 0x18, 0xde, 0xe0,
+	0x3e, 0x2a, 0xee, 0x16, 0xf3, 0xda, 0xbb, 0xe5, 0x0e, 0xf4, 0x4b, 0xae, 0x25, 0x16, 0x1e, 0xf1,
+	0x64, 0x1a, 0x7c, 0xaa, 0x88, 0x25, 0xd7, 0x2a, 0xe2, 0xdf, 0x06, 0x90, 0x7d, 0x0c, 0xf1, 0x46,
+	0x21, 0x6b, 0x2e, 0xdd, 0xca, 0x65, 0xd0, 0xa8, 0x5e, 0x06, 0x8f, 0xe0, 0x16, 0x37, 0x11, 0xd1,
+	0x46, 0x81, 0xc7, 0x3c, 0x75, 0xa3, 0xf5, 0x68, 0x2a, 0x21, 0xec, 0x7b, 0xcc, 0x53, 0x8e, 0x12,
+	0xf4, 0xb3, 0x84, 0x5f, 0x72, 0x62, 0xf2, 0x85, 0x23, 0x37, 0x17, 0xf1, 0x5c, 0x4a, 0x98, 0x55,
+	0x2e, 0x7f, 0x19, 0xd0, 0x7f, 0x91, 0xa6, 0x74, 0x1c, 0x7d, 0x1f, 0x87, 0xd9, 0x04, 0xf3, 0x64,
+	0xd6, 0xa0, 0xe5, 0xc7, 0x99, 0xfa, 0xbe, 0x2d, 0x57, 0x6e, 0xe6, 0x06, 0xdf, 0xac, 0x0c, 0xfe,
+	0x1c, 0x75, 0x34, 0xaa, 0xd4, 0xa1, 0x51, 0x43, 0x53, 0xa7, 0x06, 0xf2, 0x19, 0x74, 0x79, 0x7a,
+	0x23, 0x1f, 0x23, 0x86, 0x89, 0xe2, 0x50, 0xe0, 0xa2, 0x3d, 0x21, 0x71, 0x2e, 0x60, 0xad, 0x0c,
+	0x54, 0xf5, 0xe2, 0x42, 0x46, 0xe7, 0xbc, 0x98, 0x84, 0x0a, 0x25, 0x5f, 0x0a, 0x36, 0xc9, 0x4e,
+	0x43, 0xea, 0x8f, 0xb8, 0xa2, 0xa1, 0xd8, 0x44, 0x48, 0x4e, 0x92, 0x70, 0x96, 0x73, 0x53, 0xcb,
+	0xd9, 0xf9, 0x1a, 0xfa, 0xf2, 0x65, 0x54, 0x2e, 0xd0, 0x06, 0xc0, 0x85, 0x10, 0x8c, 0x68, 0x20,
+	0x1f, 0x05, 0x96, 0x6b, 0x49, 0xc9, 0xeb, 0x20, 0x75, 0xbe, 0x05, 0xeb, 0x30, 0x96, 0x39, 0xa7,
+	0x64, 0x07, 0xac, 0x30, 0xdf, 0xa8, 0xf7, 0x03, 0x99, 0xb5, 0x5c, 0x6e, 0xe7, 0xce, 0x8c, 0x9c,
+	0xe7, 0xd0, 0xc9, 0xc5, 0x79, 0x1e, 0xc6, 0xa2, 0x3c, 0xcc, 0xb9, 0x3c, 0x9c, 0x7f, 0x0d, 0x58,
+	0x2b, 0x43, 0x56, 0xa5, 0x3a, 0x81, 0x95, 0x22, 0xc4, 0x68, 0xe2, 0x4d, 0x15, 0x96, 0x1d, 0x1d,
+	0x4b, 0xf5, 0x58, 0x01, 0x30, 0x7d, 0xe3, 0x4d, 0x65, 0xf7, 0xf4, 0x42, 0x4d, 0x34, 0x78, 0x07,
+	0xab, 0x15, 0x93, 0x1a, 0x6a, 0x7a, 0xa2, 0x53, 0x53, 0x89, 0x39, 0x8b, 0xd3, 0x3a, 0x5f, 0x3d,
+	0x83, 0x7b, 0xb2, 0x61, 0xf7, 0x8a, 0xfe, 0xca, 0x6b, 0x5f, 0x6e, 0x43, 0x63, 0xbe, 0x0d, 0x9d,
+	0x01, 0xd8, 0xd5, 0xa3, 0x32, 0x99, 0xdd, 0x3f, 0xda, 0xd0, 0x3b, 0x46, 0xef, 0x12, 0x31, 0xe0,
+	0xcc, 0x96, 0x90, 0x71, 0x5e, 0xac, 0xf2, 0xcb, 0x97, 0x3c, 0x9e, 0xaf, 0x4a, 0xed, 0x53, 0x7b,
+	0xf0, 0xc5, 0x87, 0xcc, 0xd4, 0xa0, 0x2d, 0x91, 0x43, 0xe8, 0x6a, 0x4f, 0x4b, 0xb2, 0xae, 0x1d,
+	0xac, 0xbc, 0x98, 0x07, 0x1b, 0x0b, 0xb4, 0x85, 0x37, 0x0f, 0x48, 0xf5, 0x06, 0x21, 0x9f, 0x5f,
+	0x7f, 0xbf, 0x48, 0xdf, 0x8f, 0x3e, 0xe6, 0x12, 0x92, 0x80, 0x35, 0xc2, 0xd5, 0x01, 0x57, 0x29,
+	0x5e, 0x07, 0x5c, 0xc7, 0xd2, 0xc2, 0x9b, 0x46, 0xa6, 0xba, 0xb7, 0x2a, 0x7d, 0xeb, 0xde, 0xea,
+	0x18, 0x58, 0x78, 0xd3, 0xe8, 0x4c, 0xf7, 0x56, 0x65, 0x66, 0xdd, 0x5b, 0x1d, 0x07, 0x2e, 0x91,
+	0xb7, 0xd0, 0xd3, 0xb9, 0x85, 0x68, 0x07, 0x6a, 0xc8, 0x71, 0xf0, 0x60, 0x91, 0x5a, 0x77, 0xa8,
+	0x8f, 0x92, 0xee, 0xb0, 0x86, 0x4c, 0x74, 0x87, 0x75, 0x13, 0xe8, 0x2c, 0x91, 0x1f, 0xe1, 0xf6,
+	0x7c, 0x4b, 0x93, 0x87, 0xf3, 0x69, 0x55, 0x26, 0x65, 0xe0, 0x5c, 0x67, 0x92, 0x3b, 0x3f, 0x6d,
+	0x8b, 0xdf, 0xcb, 0xaf, 0xfe, 0x0b, 0x00, 0x00, 0xff, 0xff, 0xbf, 0xe3, 0x2a, 0x44, 0x6d, 0x0e,
+	0x00, 0x00,
 }
diff --git a/weed/s3api/filer_multipart.go b/weed/s3api/filer_multipart.go
index d85a94326..cfd46c9f8 100644
--- a/weed/s3api/filer_multipart.go
+++ b/weed/s3api/filer_multipart.go
@@ -1,11 +1,18 @@
 package s3api
 
 import (
-	"github.com/aws/aws-sdk-go/service/s3"
+	"fmt"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"time"
+
 	"github.com/aws/aws-sdk-go/aws"
-	"github.com/satori/go.uuid"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/chrislusf/seaweedfs/weed/filer2"
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/filer_pb"
+	"github.com/satori/go.uuid"
 )
 
 func (s3a *S3ApiServer) createMultipartUpload(input *s3.CreateMultipartUploadInput) (output *s3.CreateMultipartUploadOutput, code ErrorCode) {
@@ -14,9 +21,9 @@ func (s3a *S3ApiServer) createMultipartUpload(input *s3.CreateMultipartUploadInp
 
 	if err := s3a.mkdir(s3a.genUploadsFolder(*input.Bucket), uploadIdString, func(entry *filer_pb.Entry) {
 		if entry.Extended == nil {
-			entry.Extended = make(map[string]string)
+			entry.Extended = make(map[string][]byte)
 		}
-		entry.Extended["key"] = *input.Key
+		entry.Extended["key"] = []byte(*input.Key)
 	}); err != nil {
 		glog.Errorf("NewMultipartUpload error: %v", err)
 		return nil, ErrInternalError
@@ -32,19 +39,76 @@ func (s3a *S3ApiServer) createMultipartUpload(input *s3.CreateMultipartUploadInp
 }
 
 func (s3a *S3ApiServer) completeMultipartUpload(input *s3.CompleteMultipartUploadInput) (output *s3.CompleteMultipartUploadOutput, code ErrorCode) {
+
+	uploadDirectory := s3a.genUploadsFolder(*input.Bucket) + "/" + *input.UploadId
+
+	entries, err := s3a.list(uploadDirectory, "", "", false, 0)
+	if err != nil {
+		glog.Errorf("completeMultipartUpload %s *s error: %v", *input.Bucket, *input.UploadId, err)
+		return nil, ErrNoSuchUpload
+	}
+
+	var finalParts []*filer_pb.FileChunk
+	var offset int64
+
+	for _, entry := range entries {
+		if strings.HasSuffix(entry.Name, ".part") && !entry.IsDirectory {
+			for _, chunk := range entry.Chunks {
+				finalParts = append(finalParts, &filer_pb.FileChunk{
+					FileId: chunk.FileId,
+					Offset: offset,
+					Size:   chunk.Size,
+					Mtime:  chunk.Mtime,
+					ETag:   chunk.ETag,
+				})
+				offset += int64(chunk.Size)
+			}
+		}
+	}
+
+	entryName := filepath.Base(*input.Key)
+	dirName := filepath.Dir(*input.Key)
+	if dirName == "." {
+		dirName = ""
+	}
+	dirName = fmt.Sprintf("%s/%s/%s", s3a.option.BucketsPath, *input.Bucket, dirName)
+
+	err = s3a.mkFile(dirName, entryName, finalParts)
+
+	if err != nil {
+		glog.Errorf("completeMultipartUpload %s/%s error: %v", dirName, entryName, err)
+		return nil, ErrInternalError
+	}
+
+	output = &s3.CompleteMultipartUploadOutput{
+		Bucket: input.Bucket,
+		ETag:   aws.String("\"" + filer2.ETag(finalParts) + "\""),
+		Key:    input.Key,
+	}
+
 	return
 }
 
 func (s3a *S3ApiServer) abortMultipartUpload(input *s3.AbortMultipartUploadInput) (output *s3.AbortMultipartUploadOutput, code ErrorCode) {
-	return
-}
 
-func (s3a *S3ApiServer) listMultipartUploads(input *s3.ListMultipartUploadsInput) (output *s3.ListMultipartUploadsOutput, code ErrorCode) {
-	entries, err := s3a.list(s3a.genUploadsFolder(*input.Bucket))
+	exists, err := s3a.exists(s3a.genUploadsFolder(*input.Bucket), *input.UploadId, true)
 	if err != nil {
-		glog.Errorf("listMultipartUploads %s error: %v", *input.Bucket, err)
+		glog.V(1).Infof("bucket %s abort upload %s: %v", *input.Bucket, *input.UploadId, err)
 		return nil, ErrNoSuchUpload
 	}
+	if exists {
+		err = s3a.rm(s3a.genUploadsFolder(*input.Bucket), *input.UploadId, true, true, true)
+	}
+	if err != nil {
+		glog.V(1).Infof("bucket %s remove upload %s: %v", *input.Bucket, *input.UploadId, err)
+		return nil, ErrInternalError
+	}
+
+	return &s3.AbortMultipartUploadOutput{}, ErrNone
+}
+
+func (s3a *S3ApiServer) listMultipartUploads(input *s3.ListMultipartUploadsInput) (output *s3.ListMultipartUploadsOutput, code ErrorCode) {
+
 	output = &s3.ListMultipartUploadsOutput{
 		Bucket:       input.Bucket,
 		Delimiter:    input.Delimiter,
@@ -53,11 +117,18 @@ func (s3a *S3ApiServer) listMultipartUploads(input *s3.ListMultipartUploadsInput
 		MaxUploads:   input.MaxUploads,
 		Prefix:       input.Prefix,
 	}
+
+	entries, err := s3a.list(s3a.genUploadsFolder(*input.Bucket), *input.Prefix, *input.KeyMarker, true, int(*input.MaxUploads))
+	if err != nil {
+		glog.Errorf("listMultipartUploads %s error: %v", *input.Bucket, err)
+		return
+	}
+
 	for _, entry := range entries {
 		if entry.Extended != nil {
 			key := entry.Extended["key"]
 			output.Uploads = append(output.Uploads, &s3.MultipartUpload{
-				Key:      aws.String(key),
+				Key:      aws.String(string(key)),
 				UploadId: aws.String(entry.Name),
 			})
 		}
@@ -66,5 +137,37 @@ func (s3a *S3ApiServer) listMultipartUploads(input *s3.ListMultipartUploadsInput
 }
 
 func (s3a *S3ApiServer) listObjectParts(input *s3.ListPartsInput) (output *s3.ListPartsOutput, code ErrorCode) {
+	output = &s3.ListPartsOutput{
+		Bucket:           input.Bucket,
+		Key:              input.Key,
+		UploadId:         input.UploadId,
+		MaxParts:         input.MaxParts,         // the maximum number of parts to return.
+		PartNumberMarker: input.PartNumberMarker, // the part number starts after this, exclusive
+	}
+
+	entries, err := s3a.list(s3a.genUploadsFolder(*input.Bucket)+"/"+*input.UploadId,
+		"", fmt.Sprintf("%04d.part", *input.PartNumberMarker), false, int(*input.MaxParts))
+	if err != nil {
+		glog.Errorf("listObjectParts %s *s error: %v", *input.Bucket, *input.UploadId, err)
+		return nil, ErrNoSuchUpload
+	}
+
+	for _, entry := range entries {
+		if strings.HasSuffix(entry.Name, ".part") && !entry.IsDirectory {
+			partNumberString := entry.Name[:len(entry.Name)-len(".part")]
+			partNumber, err := strconv.Atoi(partNumberString)
+			if err != nil {
+				glog.Errorf("listObjectParts %s *s parse %s: %v", *input.Bucket, *input.UploadId, entry.Name, err)
+				continue
+			}
+			output.Parts = append(output.Parts, &s3.Part{
+				PartNumber:   aws.Int64(int64(partNumber)),
+				LastModified: aws.Time(time.Unix(entry.Attributes.Mtime, 0)),
+				Size:         aws.Int64(int64(filer2.TotalSize(entry.Chunks))),
+				ETag:         aws.String("\"" + filer2.ETag(entry.Chunks) + "\""),
+			})
+		}
+	}
+
 	return
 }
diff --git a/weed/s3api/filer_util.go b/weed/s3api/filer_util.go
index a44305505..f0949389c 100644
--- a/weed/s3api/filer_util.go
+++ b/weed/s3api/filer_util.go
@@ -34,7 +34,7 @@ func (s3a *S3ApiServer) mkdir(parentDirectoryPath string, dirName string, fn fun
 			Entry:     entry,
 		}
 
-		glog.V(1).Infof("create bucket: %v", request)
+		glog.V(1).Infof("mkdir: %v", request)
 		if _, err := client.CreateEntry(context.Background(), request); err != nil {
 			return fmt.Errorf("mkdir %s/%s: %v", parentDirectoryPath, dirName, err)
 		}
@@ -43,12 +43,46 @@ func (s3a *S3ApiServer) mkdir(parentDirectoryPath string, dirName string, fn fun
 	})
 }
 
-func (s3a *S3ApiServer) list(parentDirectoryPath string) (entries []*filer_pb.Entry, err error) {
+func (s3a *S3ApiServer) mkFile(parentDirectoryPath string, fileName string, chunks []*filer_pb.FileChunk) error {
+	return s3a.withFilerClient(func(client filer_pb.SeaweedFilerClient) error {
+
+		entry := &filer_pb.Entry{
+			Name:        fileName,
+			IsDirectory: false,
+			Attributes: &filer_pb.FuseAttributes{
+				Mtime:    time.Now().Unix(),
+				Crtime:   time.Now().Unix(),
+				FileMode: uint32(0770),
+				Uid:      OS_UID,
+				Gid:      OS_GID,
+			},
+			Chunks: chunks,
+		}
+
+		request := &filer_pb.CreateEntryRequest{
+			Directory: parentDirectoryPath,
+			Entry:     entry,
+		}
+
+		glog.V(1).Infof("create file: %s/%s", parentDirectoryPath, fileName)
+		if _, err := client.CreateEntry(context.Background(), request); err != nil {
+			return fmt.Errorf("create file %s/%s: %v", parentDirectoryPath, fileName, err)
+		}
+
+		return nil
+	})
+}
+
+func (s3a *S3ApiServer) list(parentDirectoryPath, prefix, startFrom string, inclusive bool, limit int) (entries []*filer_pb.Entry, err error) {
 
 	err = s3a.withFilerClient(func(client filer_pb.SeaweedFilerClient) error {
 
 		request := &filer_pb.ListEntriesRequest{
-			Directory: s3a.option.BucketsPath,
+			Directory:          s3a.option.BucketsPath,
+			Prefix:             prefix,
+			StartFromFileName:  startFrom,
+			InclusiveStartFrom: inclusive,
+			Limit:              uint32(limit),
 		}
 
 		glog.V(4).Infof("read directory: %v", request)
@@ -101,10 +135,10 @@ func (s3a *S3ApiServer) exists(parentDirectoryPath string, entryName string, isD
 			Name:      entryName,
 		}
 
-		glog.V(1).Infof("delete entry %v/%v: %v", parentDirectoryPath, entryName, request)
+		glog.V(1).Infof("exists entry %v/%v: %v", parentDirectoryPath, entryName, request)
 		resp, err := client.LookupDirectoryEntry(ctx, request)
 		if err != nil {
-			return fmt.Errorf("delete entry %s/%s: %v", parentDirectoryPath, entryName, err)
+			return fmt.Errorf("exists entry %s/%s: %v", parentDirectoryPath, entryName, err)
 		}
 
 		exists = resp.Entry.IsDirectory == isDirectory
diff --git a/weed/s3api/s3api_bucket_handlers.go b/weed/s3api/s3api_bucket_handlers.go
index 5257e67b4..df9abd451 100644
--- a/weed/s3api/s3api_bucket_handlers.go
+++ b/weed/s3api/s3api_bucket_handlers.go
@@ -21,7 +21,7 @@ func (s3a *S3ApiServer) ListBucketsHandler(w http.ResponseWriter, r *http.Reques
 
 	var response ListAllMyBucketsResponse
 
-	entries, err := s3a.list(s3a.option.BucketsPath)
+	entries, err := s3a.list(s3a.option.BucketsPath, "", "", false, 0)
 
 	if err != nil {
 		writeErrorResponse(w, ErrInternalError, r.URL)
diff --git a/weed/s3api/s3api_object_multipart_handlers.go b/weed/s3api/s3api_object_multipart_handlers.go
index 62b702a39..d9baa9aae 100644
--- a/weed/s3api/s3api_object_multipart_handlers.go
+++ b/weed/s3api/s3api_object_multipart_handlers.go
@@ -1,16 +1,16 @@
 package s3api
 
 import (
-	"net/http"
-	"github.com/gorilla/mux"
+	"encoding/xml"
 	"fmt"
-	"github.com/aws/aws-sdk-go/service/s3"
 	"github.com/aws/aws-sdk-go/aws"
-	"net/url"
-	"strconv"
+	"github.com/aws/aws-sdk-go/service/s3"
+	"github.com/gorilla/mux"
 	"io/ioutil"
-	"encoding/xml"
+	"net/http"
+	"net/url"
 	"sort"
+	"strconv"
 	"strings"
 )
 
@@ -143,6 +143,8 @@ func (s3a *S3ApiServer) ListMultipartUploadsHandler(w http.ResponseWriter, r *ht
 		return
 	}
 
+	// TODO handle encodingType
+
 	writeSuccessResponseXML(w, encodeResponse(response))
 }
 
diff --git a/weed/s3api/s3api_objects_list_handlers.go b/weed/s3api/s3api_objects_list_handlers.go
index 721982d0f..d751a3b1d 100644
--- a/weed/s3api/s3api_objects_list_handlers.go
+++ b/weed/s3api/s3api_objects_list_handlers.go
@@ -126,7 +126,7 @@ func (s3a *S3ApiServer) listFilerEntries(bucket, originalPrefix string, maxKeys
 				contents = append(contents, &s3.Object{
 					Key:          aws.String(fmt.Sprintf("%s%s", dir, entry.Name)),
 					LastModified: aws.Time(time.Unix(entry.Attributes.Mtime, 0)),
-					ETag:         aws.String("\"2345sgfwetrewrt\""), // TODO add etag
+					ETag:         aws.String("\"" + filer2.ETag(entry.Chunks) + "\""),
 					Size:         aws.Int64(int64(filer2.TotalSize(entry.Chunks))),
 					Owner: &s3.Owner{
 						ID:          aws.String("bcaf161ca5fb16fd081034f"),
diff --git a/weed/s3api/s3api_server.go b/weed/s3api/s3api_server.go
index efeeb34ce..a62b521de 100644
--- a/weed/s3api/s3api_server.go
+++ b/weed/s3api/s3api_server.go
@@ -37,7 +37,7 @@ func (s3a *S3ApiServer) registerRouter(router *mux.Router) {
 	apiRouter := router.PathPrefix("/").Subrouter()
 	var routers []*mux.Router
 	if s3a.option.DomainName != "" {
-		routers = append(routers, apiRouter.Host("{bucket:.+}."+ s3a.option.DomainName).Subrouter())
+		routers = append(routers, apiRouter.Host("{bucket:.+}."+s3a.option.DomainName).Subrouter())
 	}
 	routers = append(routers, apiRouter.PathPrefix("/{bucket}").Subrouter())
 
diff --git a/weed/server/filer_server_handlers_read.go b/weed/server/filer_server_handlers_read.go
index e17cd776d..eaa8015a6 100644
--- a/weed/server/filer_server_handlers_read.go
+++ b/weed/server/filer_server_handlers_read.go
@@ -119,6 +119,7 @@ func (fs *FilerServer) handleMultipleChunks(w http.ResponseWriter, r *http.Reque
 	if mimeType != "" {
 		w.Header().Set("Content-Type", mimeType)
 	}
+	setEtag(w, filer2.ETag(entry.Chunks))
 
 	totalSize := int64(filer2.TotalSize(entry.Chunks))
 
diff --git a/weed/server/filer_server_handlers_write.go b/weed/server/filer_server_handlers_write.go
index 8a19f3fdb..2f9351fa1 100644
--- a/weed/server/filer_server_handlers_write.go
+++ b/weed/server/filer_server_handlers_write.go
@@ -150,6 +150,7 @@ func (fs *FilerServer) PostHandler(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 	defer resp.Body.Close()
+	etag := resp.Header.Get("ETag")
 	resp_body, ra_err := ioutil.ReadAll(resp.Body)
 	if ra_err != nil {
 		glog.V(0).Infoln("failing to upload to volume server", r.RequestURI, ra_err.Error())
@@ -202,6 +203,7 @@ func (fs *FilerServer) PostHandler(w http.ResponseWriter, r *http.Request) {
 			FileId: fileId,
 			Size:   uint64(ret.Size),
 			Mtime:  time.Now().UnixNano(),
+			ETag:   etag,
 		}},
 	}
 	if db_err := fs.filer.CreateEntry(entry); db_err != nil {
diff --git a/weed/server/volume_server_handlers_read.go b/weed/server/volume_server_handlers_read.go
index 64b90b8e7..4da13883e 100644
--- a/weed/server/volume_server_handlers_read.go
+++ b/weed/server/volume_server_handlers_read.go
@@ -68,7 +68,7 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 	count, e := vs.store.ReadVolumeNeedle(volumeId, n)
 	glog.V(4).Infoln("read bytes", count, "error", e)
 	if e != nil || count < 0 {
-		glog.V(0).Infoln("read error:", e, r.URL.Path)
+		glog.V(0).Infof("read %s error: %v", r.URL.Path, e)
 		w.WriteHeader(http.StatusNotFound)
 		return
 	}
@@ -88,12 +88,11 @@ func (vs *VolumeServer) GetOrHeadHandler(w http.ResponseWriter, r *http.Request)
 			}
 		}
 	}
-	etag := n.Etag()
-	if inm := r.Header.Get("If-None-Match"); inm == etag {
+	if inm := r.Header.Get("If-None-Match"); inm == "\""+n.Etag()+"\"" {
 		w.WriteHeader(http.StatusNotModified)
 		return
 	}
-	w.Header().Set("Etag", etag)
+	setEtag(w, n.Etag())
 
 	if n.HasPairs() {
 		pairMap := make(map[string]string)
diff --git a/weed/server/volume_server_handlers_write.go b/weed/server/volume_server_handlers_write.go
index d32958339..a0b142dea 100644
--- a/weed/server/volume_server_handlers_write.go
+++ b/weed/server/volume_server_handlers_write.go
@@ -44,8 +44,7 @@ func (vs *VolumeServer) PostHandler(w http.ResponseWriter, r *http.Request) {
 		ret.Name = string(needle.Name)
 	}
 	ret.Size = size
-	etag := needle.Etag()
-	w.Header().Set("Etag", etag)
+	setEtag(w, needle.Etag())
 	writeJsonQuiet(w, r, httpStatus, ret)
 }
 
@@ -173,3 +172,9 @@ func (vs *VolumeServer) batchDeleteHandler(w http.ResponseWriter, r *http.Reques
 
 	writeJsonQuiet(w, r, http.StatusAccepted, ret)
 }
+
+func setEtag(w http.ResponseWriter, etag string) {
+	if etag != "" {
+		w.Header().Set("ETag", "\""+etag+"\"")
+	}
+}
diff --git a/weed/storage/crc.go b/weed/storage/crc.go
index 494937784..e31e0f815 100644
--- a/weed/storage/crc.go
+++ b/weed/storage/crc.go
@@ -26,5 +26,5 @@ func (c CRC) Value() uint32 {
 func (n *Needle) Etag() string {
 	bits := make([]byte, 4)
 	util.Uint32toBytes(bits, uint32(n.Checksum))
-	return fmt.Sprintf("\"%x\"", bits)
+	return fmt.Sprintf("%x", bits)
 }
diff --git a/weed/storage/volume_loading.go b/weed/storage/volume_loading.go
index 572220650..37a6e07b2 100644
--- a/weed/storage/volume_loading.go
+++ b/weed/storage/volume_loading.go
@@ -19,8 +19,9 @@ func loadVolumeWithoutIndex(dirname string, collection string, id VolumeId, need
 func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind NeedleMapType, preallocate int64) error {
 	var e error
 	fileName := v.FileName()
+	alreadyHasSuperBlock := false
 
-	if exists, canRead, canWrite, modifiedTime := checkFile(fileName + ".dat"); exists {
+	if exists, canRead, canWrite, modifiedTime, fileSize := checkFile(fileName + ".dat"); exists {
 		if !canRead {
 			return fmt.Errorf("cannot read Volume Data file %s.dat", fileName)
 		}
@@ -32,6 +33,9 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 			v.dataFile, e = os.Open(fileName + ".dat")
 			v.readOnly = true
 		}
+		if fileSize >= _SuperBlockSize {
+			alreadyHasSuperBlock = true
+		}
 	} else {
 		if createDatIfMissing {
 			v.dataFile, e = createVolumeFile(fileName+".dat", preallocate)
@@ -48,7 +52,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 		}
 	}
 
-	if v.ReplicaPlacement == nil {
+	if alreadyHasSuperBlock {
 		e = v.readSuperBlock()
 	} else {
 		e = v.maybeWriteSuperBlock()
@@ -97,7 +101,7 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 	return e
 }
 
-func checkFile(filename string) (exists, canRead, canWrite bool, modTime time.Time) {
+func checkFile(filename string) (exists, canRead, canWrite bool, modTime time.Time, fileSize int64) {
 	exists = true
 	fi, err := os.Stat(filename)
 	if os.IsNotExist(err) {
@@ -111,5 +115,6 @@ func checkFile(filename string) (exists, canRead, canWrite bool, modTime time.Ti
 		canWrite = true
 	}
 	modTime = fi.ModTime()
+	fileSize = fi.Size()
 	return
 }
diff --git a/weed/util/constants.go b/weed/util/constants.go
index 713886b0e..fda15d96a 100644
--- a/weed/util/constants.go
+++ b/weed/util/constants.go
@@ -1,5 +1,5 @@
 package util
 
 const (
-	VERSION = "0.95"
+	VERSION = "0.96"
 )