XL - fixes mostly related to multipart listing. (#1441)

* XL/Multipart: Use json.NewDecoder to decode read stream.

* XL/Multipart: fix recursive and non-recursive listing.

* XL/Multipart: Create object part with md5sum later using RenameFile.

* XL/Multipart: ListObjectParts should list parts in order.

previously: uploadID.10.md5sum < uploadID.2.md5sum
fix       : uploadID.00010.md5sum > uploadID.00002.md5sum

* XL/Multipart: Keep the size of each part in the multipart metadata file to avoid stats on the parts.

* XL/Multipart: fix listing bug which was showing size of the multipart uploaded objects as 0.

xl-objects.go

@@ -20,8 +20,8 @@ import (
 	"crypto/md5"
 	"encoding/hex"
 	"encoding/json"
-	"fmt"
 	"io"
+	"path"
 	"path/filepath"
 	"strings"
 
@@ -29,7 +29,8 @@ import (
 )
 
 const (
-	multipartMetaFile = "multipart.json"
+	multipartSuffix   = ".minio.multipart"
+	multipartMetaFile = "00000" + multipartSuffix
 )
 
 // xlObjects - Implements fs object layer.
@@ -72,25 +73,6 @@ func (xl xlObjects) DeleteBucket(bucket string) error {
 
 // GetObject - get an object.
 func (xl xlObjects) GetObject(bucket, object string, startOffset int64) (io.ReadCloser, error) {
-	findPartOffset := func(parts completedParts) (partIndex int, partOffset int64, err error) {
-		partOffset = startOffset
-		for i, part := range parts {
-			partIndex = i
-			var fileInfo FileInfo
-			fileInfo, err = xl.storage.StatFile(bucket, pathJoin(object, fmt.Sprint(part.PartNumber)))
-			if err != nil {
-				return
-			}
-			if partOffset < fileInfo.Size {
-				return
-			}
-			partOffset -= fileInfo.Size
-		}
-		// Offset beyond the size of the object
-		err = errUnexpected
-		return
-	}
-
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
 		return nil, BucketNameInvalid{Bucket: bucket}
@@ -111,18 +93,18 @@ func (xl xlObjects) GetObject(bucket, object string, startOffset int64) (io.Read
 		return nil, toObjectErr(err, bucket, object)
 	}
 	fileReader, fileWriter := io.Pipe()
-	parts, err := xl.getParts(bucket, object)
+	info, err := xl.getMultipartObjectInfo(bucket, object)
 	if err != nil {
 		return nil, toObjectErr(err, bucket, object)
 	}
-	partIndex, offset, err := findPartOffset(parts)
+	partIndex, offset, err := info.GetPartNumberOffset(startOffset)
 	if err != nil {
 		return nil, toObjectErr(err, bucket, object)
 	}
 	go func() {
-		for ; partIndex < len(parts); partIndex++ {
-			part := parts[partIndex]
-			r, err := xl.storage.ReadFile(bucket, pathJoin(object, fmt.Sprint(part.PartNumber)), offset)
+		for ; partIndex < len(info); partIndex++ {
+			part := info[partIndex]
+			r, err := xl.storage.ReadFile(bucket, pathJoin(object, partNumToPartFileName(part.PartNumber)), offset)
 			if err != nil {
 				fileWriter.CloseWithError(err)
 				return
@@ -138,38 +120,19 @@ func (xl xlObjects) GetObject(bucket, object string, startOffset int64) (io.Read
 }
 
 // Return the parts of a multipart upload.
-func (xl xlObjects) getParts(bucket, object string) (parts completedParts, err error) {
+func (xl xlObjects) getMultipartObjectInfo(bucket, object string) (info MultipartObjectInfo, err error) {
 	offset := int64(0)
 	r, err := xl.storage.ReadFile(bucket, pathJoin(object, multipartMetaFile), offset)
 	if err != nil {
 		return
 	}
-	// FIXME: what if multipart.json is > 4MB
-	b := make([]byte, 4*1024*1024)
-	n, err := io.ReadFull(r, b)
-	if err != nil && err != io.ErrUnexpectedEOF {
-		return
-	}
-	b = b[:n]
-	err = json.Unmarshal(b, &parts)
-	if err != nil {
-		return
-	}
+	decoder := json.NewDecoder(r)
+	err = decoder.Decode(&info)
 	return
 }
 
 // GetObjectInfo - get object info.
 func (xl xlObjects) GetObjectInfo(bucket, object string) (ObjectInfo, error) {
-	getMultpartFileSize := func(parts completedParts) (size int64) {
-		for _, part := range parts {
-			fi, err := xl.storage.StatFile(bucket, pathJoin(object, fmt.Sprint(part.PartNumber)))
-			if err != nil {
-				continue
-			}
-			size += fi.Size
-		}
-		return size
-	}
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
 		return ObjectInfo{}, BucketNameInvalid{Bucket: bucket}
@@ -180,11 +143,11 @@ func (xl xlObjects) GetObjectInfo(bucket, object string) (ObjectInfo, error) {
 	}
 	fi, err := xl.storage.StatFile(bucket, object)
 	if err != nil {
-		parts, err := xl.getParts(bucket, object)
+		info, err := xl.getMultipartObjectInfo(bucket, object)
 		if err != nil {
 			return ObjectInfo{}, toObjectErr(err, bucket, object)
 		}
-		fi.Size = getMultpartFileSize(parts)
+		fi.Size = info.GetSize()
 	}
 	contentType := "application/octet-stream"
 	if objectExt := filepath.Ext(object); objectExt != "" {
@@ -287,6 +250,8 @@ func (xl xlObjects) DeleteObject(bucket, object string) error {
 	return nil
 }
 
+// TODO - support non-recursive case, figure out file size for files uploaded using multipart.
+
 func (xl xlObjects) ListObjects(bucket, prefix, marker, delimiter string, maxKeys int) (ListObjectsInfo, error) {
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
@@ -311,21 +276,71 @@ func (xl xlObjects) ListObjects(bucket, prefix, marker, delimiter string, maxKey
 		}
 	}
 
+	if maxKeys == 0 {
+		return ListObjectsInfo{}, nil
+	}
+
 	// Default is recursive, if delimiter is set then list non recursive.
 	recursive := true
 	if delimiter == slashSeparator {
 		recursive = false
 	}
-	fileInfos, eof, err := xl.storage.ListFiles(bucket, prefix, marker, recursive, maxKeys)
-	if err != nil {
-		return ListObjectsInfo{}, toObjectErr(err, bucket)
-	}
-	if maxKeys == 0 {
-		return ListObjectsInfo{}, nil
+	var allFileInfos, fileInfos []FileInfo
+	var eof bool
+	var err error
+	for {
+		fileInfos, eof, err = xl.storage.ListFiles(bucket, prefix, marker, recursive, maxKeys)
+		if err != nil {
+			return ListObjectsInfo{}, toObjectErr(err, bucket)
+		}
+		for _, fileInfo := range fileInfos {
+			// FIXME: use fileInfo.Mode.IsDir() instead after fixing the bug in
+			// XL listing which is not reseting the Mode to 0 for leaf dirs.
+			if strings.HasSuffix(fileInfo.Name, slashSeparator) {
+				if isLeafDirectory(xl.storage, bucket, fileInfo.Name) {
+					fileInfo.Name = strings.TrimSuffix(fileInfo.Name, slashSeparator)
+					// Set the Mode to a "regular" file.
+					fileInfo.Mode = 0
+					var info MultipartObjectInfo
+					info, err = xl.getMultipartObjectInfo(bucket, fileInfo.Name)
+					if err != nil {
+						return ListObjectsInfo{}, toObjectErr(err, bucket)
+					}
+					fileInfo.Size = info.GetSize()
+					allFileInfos = append(allFileInfos, fileInfo)
+					maxKeys--
+					continue
+				}
+			}
+			if strings.HasSuffix(fileInfo.Name, multipartMetaFile) {
+				fileInfo.Name = path.Dir(fileInfo.Name)
+				var info MultipartObjectInfo
+				info, err = xl.getMultipartObjectInfo(bucket, fileInfo.Name)
+				if err != nil {
+					return ListObjectsInfo{}, toObjectErr(err, bucket)
+				}
+				fileInfo.Size = info.GetSize()
+				allFileInfos = append(allFileInfos, fileInfo)
+				maxKeys--
+				continue
+			}
+			if strings.HasSuffix(fileInfo.Name, multipartSuffix) {
+				continue
+			}
+			allFileInfos = append(allFileInfos, fileInfo)
+			maxKeys--
+		}
+		if maxKeys == 0 {
+			break
+		}
+		if eof {
+			break
+		}
 	}
 
 	result := ListObjectsInfo{IsTruncated: !eof}
-	for _, fileInfo := range fileInfos {
+
+	for _, fileInfo := range allFileInfos {
 		// With delimiter set we fill in NextMarker and Prefixes.
 		if delimiter == slashSeparator {
 			result.NextMarker = fileInfo.Name