xl/fs: Bring in ".minio/tmp" directory support. (#1464)

All transactions happen through this directory inside ".minio/temp".
Adding this allows us to remove any temporary files which were not
committed before.

Fixes #1462
Fixes #1444

fs-objects-multipart.go

@@ -20,231 +20,11 @@ import (
 	"fmt"
 	"io"
 	"path"
-	"strconv"
-	"strings"
-
-	"github.com/Sirupsen/logrus"
-	"github.com/skyrings/skyring-common/tools/uuid"
 )
 
-// listLeafEntries - lists all entries if a given prefixPath is a leaf
-// directory, returns error if any - returns empty list if prefixPath
-// is not a leaf directory.
-func (fs fsObjects) listLeafEntries(prefixPath string) (entries []FileInfo, e error) {
-	var markerPath string
-	for {
-		fileInfos, eof, err := fs.storage.ListFiles(minioMetaBucket, prefixPath, markerPath, false, 1000)
-		if err != nil {
-			log.WithFields(logrus.Fields{
-				"prefixPath": prefixPath,
-				"markerPath": markerPath,
-			}).Errorf("%s", err)
-			return nil, err
-		}
-		for _, fileInfo := range fileInfos {
-			// Set marker for next batch of ListFiles.
-			markerPath = fileInfo.Name
-			if fileInfo.Mode.IsDir() {
-				// If a directory is found, doesn't return anything.
-				return nil, nil
-			}
-			fileName := path.Base(fileInfo.Name)
-			if !strings.Contains(fileName, ".") {
-				// Skip the entry if it is of the pattern bucket/object/uploadID.partNum.md5sum
-				// and retain entries of the pattern bucket/object/uploadID
-				entries = append(entries, fileInfo)
-			}
-		}
-		if eof {
-			break
-		}
-	}
-	return entries, nil
-}
-
-// listMetaBucketFiles - list all files at a given prefix inside minioMetaBucket.
-func (fs fsObjects) listMetaBucketFiles(prefixPath string, markerPath string, recursive bool, maxKeys int) (allFileInfos []FileInfo, eof bool, err error) {
-	// newMaxKeys tracks the size of entries which are going to be
-	// returned back.
-	var newMaxKeys int
-
-	// Following loop gathers and filters out special files inside
-	// minio meta volume.
-	for {
-		var fileInfos []FileInfo
-		// List files up to maxKeys-newMaxKeys, since we are skipping entries for special files.
-		fileInfos, eof, err = fs.storage.ListFiles(minioMetaBucket, prefixPath, markerPath, recursive, maxKeys-newMaxKeys)
-		if err != nil {
-			log.WithFields(logrus.Fields{
-				"prefixPath": prefixPath,
-				"markerPath": markerPath,
-				"recursive":  recursive,
-				"maxKeys":    maxKeys,
-			}).Errorf("%s", err)
-			return nil, true, err
-		}
-		// Loop through and validate individual file.
-		for _, fi := range fileInfos {
-			var entries []FileInfo
-			if fi.Mode.IsDir() {
-				// List all the entries if fi.Name is a leaf directory, if
-				// fi.Name is not a leaf directory then the resulting
-				// entries are empty.
-				entries, err = fs.listLeafEntries(fi.Name)
-				if err != nil {
-					log.WithFields(logrus.Fields{
-						"prefixPath": fi.Name,
-					}).Errorf("%s", err)
-					return nil, false, err
-				}
-			}
-			// Set markerPath for next batch of listing.
-			markerPath = fi.Name
-			if len(entries) > 0 {
-				// We reach here for non-recursive case and a leaf entry.
-				for _, entry := range entries {
-					allFileInfos = append(allFileInfos, entry)
-					newMaxKeys++
-					// If we have reached the maxKeys, it means we have listed
-					// everything that was requested. Return right here.
-					if newMaxKeys == maxKeys {
-						// Return values:
-						// allFileInfos : "maxKeys" number of entries.
-						// eof : eof returned by fs.storage.ListFiles()
-						// error : nil
-						return
-					}
-				}
-			} else {
-				// We reach here for a non-recursive case non-leaf entry
-				// OR recursive case with fi.Name matching pattern bucket/object/uploadID[.partNum.md5sum]
-				if !fi.Mode.IsDir() { // Do not skip non-recursive case directory entries.
-					// Skip files matching pattern bucket/object/uploadID.partNum.md5sum
-					// and retain files matching pattern bucket/object/uploadID
-					specialFile := path.Base(fi.Name)
-					if strings.Contains(specialFile, ".") {
-						// Contains partnumber and md5sum info, skip this.
-						continue
-					}
-				}
-			}
-			allFileInfos = append(allFileInfos, fi)
-			newMaxKeys++
-			// If we have reached the maxKeys, it means we have listed
-			// everything that was requested. Return right here.
-			if newMaxKeys == maxKeys {
-				// Return values:
-				// allFileInfos : "maxKeys" number of entries.
-				// eof : eof returned by fs.storage.ListFiles()
-				// error : nil
-				return
-			}
-		}
-		// If we have reached eof then we break out.
-		if eof {
-			break
-		}
-	}
-
-	// Return entries here.
-	return allFileInfos, eof, nil
-}
-
 // ListMultipartUploads - list multipart uploads.
 func (fs fsObjects) ListMultipartUploads(bucket, prefix, keyMarker, uploadIDMarker, delimiter string, maxUploads int) (ListMultipartsInfo, error) {
-	result := ListMultipartsInfo{}
-	// Verify if bucket is valid.
-	if !IsValidBucketName(bucket) {
-		return ListMultipartsInfo{}, (BucketNameInvalid{Bucket: bucket})
-	}
-	if !IsValidObjectPrefix(prefix) {
-		return ListMultipartsInfo{}, (ObjectNameInvalid{Bucket: bucket, Object: prefix})
-	}
-	// Verify if delimiter is anything other than '/', which we do not support.
-	if delimiter != "" && delimiter != slashSeparator {
-		return ListMultipartsInfo{}, (UnsupportedDelimiter{
-			Delimiter: delimiter,
-		})
-	}
-	// Verify if marker has prefix.
-	if keyMarker != "" && !strings.HasPrefix(keyMarker, prefix) {
-		return ListMultipartsInfo{}, (InvalidMarkerPrefixCombination{
-			Marker: keyMarker,
-			Prefix: prefix,
-		})
-	}
-	if uploadIDMarker != "" {
-		if strings.HasSuffix(keyMarker, slashSeparator) {
-			return result, (InvalidUploadIDKeyCombination{
-				UploadIDMarker: uploadIDMarker,
-				KeyMarker:      keyMarker,
-			})
-		}
-		id, err := uuid.Parse(uploadIDMarker)
-		if err != nil {
-			return result, err
-		}
-		if id.IsZero() {
-			return result, (MalformedUploadID{
-				UploadID: uploadIDMarker,
-			})
-		}
-	}
-
-	recursive := true
-	if delimiter == slashSeparator {
-		recursive = false
-	}
-
-	result.IsTruncated = true
-	result.MaxUploads = maxUploads
-
-	// Not using path.Join() as it strips off the trailing '/'.
-	// Also bucket should always be followed by '/' even if prefix is empty.
-	prefixPath := pathJoin(bucket, prefix)
-	keyMarkerPath := ""
-	if keyMarker != "" {
-		keyMarkerPath = pathJoin(pathJoin(bucket, keyMarker), uploadIDMarker)
-	}
-	// List all the multipart files at prefixPath, starting with marker keyMarkerPath.
-	fileInfos, eof, err := fs.listMetaBucketFiles(prefixPath, keyMarkerPath, recursive, maxUploads)
-	if err != nil {
-		log.WithFields(logrus.Fields{
-			"prefixPath": prefixPath,
-			"markerPath": keyMarkerPath,
-			"recursive":  recursive,
-			"maxUploads": maxUploads,
-		}).Errorf("listMetaBucketFiles failed with %s", err)
-		return ListMultipartsInfo{}, err
-	}
-
-	// Loop through all the received files fill in the multiparts result.
-	for _, fi := range fileInfos {
-		var objectName string
-		var uploadID string
-		if fi.Mode.IsDir() {
-			// All directory entries are common prefixes.
-			uploadID = "" // Upload ids are empty for CommonPrefixes.
-			objectName = strings.TrimPrefix(fi.Name, retainSlash(bucket))
-			result.CommonPrefixes = append(result.CommonPrefixes, objectName)
-		} else {
-			uploadID = path.Base(fi.Name)
-			objectName = strings.TrimPrefix(path.Dir(fi.Name), retainSlash(bucket))
-			result.Uploads = append(result.Uploads, uploadMetadata{
-				Object:    objectName,
-				UploadID:  uploadID,
-				Initiated: fi.ModTime,
-			})
-		}
-		result.NextKeyMarker = objectName
-		result.NextUploadIDMarker = uploadID
-	}
-	result.IsTruncated = !eof
-	if !result.IsTruncated {
-		result.NextKeyMarker = ""
-		result.NextUploadIDMarker = ""
-	}
-	return result, nil
+	return listMultipartUploadsCommon(fs.storage, bucket, prefix, keyMarker, uploadIDMarker, delimiter, maxUploads)
 }
 
 // NewMultipartUpload - initialize a new multipart upload, returns a unique id.
@@ -254,100 +34,32 @@ func (fs fsObjects) NewMultipartUpload(bucket, object string) (string, error) {
 
 // PutObjectPart - writes the multipart upload chunks.
 func (fs fsObjects) PutObjectPart(bucket, object, uploadID string, partID int, size int64, data io.Reader, md5Hex string) (string, error) {
-	newMD5Hex, err := putObjectPartCommon(fs.storage, bucket, object, uploadID, partID, size, data, md5Hex)
-	if err != nil {
-		return "", err
-	}
-	partSuffix := fmt.Sprintf("%s.%d", uploadID, partID)
-	partSuffixPath := path.Join(bucket, object, partSuffix)
-	partSuffixMD5 := fmt.Sprintf("%s.%d.%s", uploadID, partID, newMD5Hex)
-	partSuffixMD5Path := path.Join(bucket, object, partSuffixMD5)
-	err = fs.storage.RenameFile(minioMetaBucket, partSuffixPath, minioMetaBucket, partSuffixMD5Path)
-	if err != nil {
-		return "", err
-	}
-	return newMD5Hex, nil
+	return putObjectPartCommon(fs.storage, bucket, object, uploadID, partID, size, data, md5Hex)
 }
 
 func (fs fsObjects) ListObjectParts(bucket, object, uploadID string, partNumberMarker, maxParts int) (ListPartsInfo, error) {
-	// Verify if bucket is valid.
-	if !IsValidBucketName(bucket) {
-		return ListPartsInfo{}, (BucketNameInvalid{Bucket: bucket})
-	}
-	if !IsValidObjectName(object) {
-		return ListPartsInfo{}, (ObjectNameInvalid{Bucket: bucket, Object: object})
-	}
-	if status, err := isUploadIDExists(fs.storage, bucket, object, uploadID); err != nil {
-		return ListPartsInfo{}, err
-	} else if !status {
-		return ListPartsInfo{}, (InvalidUploadID{UploadID: uploadID})
-	}
-	result := ListPartsInfo{}
-	var markerPath string
-	nextPartNumberMarker := 0
-	uploadIDPath := path.Join(bucket, object, uploadID)
-	// Figure out the marker for the next subsequent calls, if the
-	// partNumberMarker is already set.
-	if partNumberMarker > 0 {
-		partNumberMarkerPath := uploadIDPath + "." + strconv.Itoa(partNumberMarker) + "."
-		fileInfos, _, err := fs.storage.ListFiles(minioMetaBucket, partNumberMarkerPath, "", false, 1)
-		if err != nil {
-			return result, toObjectErr(err, minioMetaBucket, partNumberMarkerPath)
-		}
-		if len(fileInfos) == 0 {
-			return result, (InvalidPart{})
-		}
-		markerPath = fileInfos[0].Name
-	}
-	uploadIDPrefix := uploadIDPath + "."
-	fileInfos, eof, err := fs.storage.ListFiles(minioMetaBucket, uploadIDPrefix, markerPath, false, maxParts)
-	if err != nil {
-		return result, InvalidPart{}
-	}
-	for _, fileInfo := range fileInfos {
-		fileName := path.Base(fileInfo.Name)
-		splitResult := strings.Split(fileName, ".")
-		partNum, err := strconv.Atoi(splitResult[1])
-		if err != nil {
-			return result, err
-		}
-		md5sum := splitResult[2]
-		result.Parts = append(result.Parts, partInfo{
-			PartNumber:   partNum,
-			LastModified: fileInfo.ModTime,
-			ETag:         md5sum,
-			Size:         fileInfo.Size,
-		})
-		nextPartNumberMarker = partNum
-	}
-	result.Bucket = bucket
-	result.Object = object
-	result.UploadID = uploadID
-	result.PartNumberMarker = partNumberMarker
-	result.NextPartNumberMarker = nextPartNumberMarker
-	result.MaxParts = maxParts
-	result.IsTruncated = !eof
-	return result, nil
+	return listObjectPartsCommon(fs.storage, bucket, object, uploadID, partNumberMarker, maxParts)
 }
 
 func (fs fsObjects) CompleteMultipartUpload(bucket string, object string, uploadID string, parts []completePart) (string, error) {
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
-		return "", (BucketNameInvalid{Bucket: bucket})
+		return "", BucketNameInvalid{Bucket: bucket}
 	}
 	if !IsValidObjectName(object) {
-		return "", (ObjectNameInvalid{
+		return "", ObjectNameInvalid{
 			Bucket: bucket,
 			Object: object,
-		})
+		}
 	}
 	if status, err := isUploadIDExists(fs.storage, bucket, object, uploadID); err != nil {
 		return "", err
 	} else if !status {
-		return "", (InvalidUploadID{UploadID: uploadID})
+		return "", InvalidUploadID{UploadID: uploadID}
 	}
 
-	fileWriter, err := fs.storage.CreateFile(bucket, object)
+	tempObj := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	fileWriter, err := fs.storage.CreateFile(minioMetaBucket, tempObj)
 	if err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
@@ -355,12 +67,13 @@ func (fs fsObjects) CompleteMultipartUpload(bucket string, object string, upload
 	var md5Sums []string
 	for _, part := range parts {
 		// Construct part suffix.
-		partSuffix := fmt.Sprintf("%s.%d.%s", uploadID, part.PartNumber, part.ETag)
+		partSuffix := fmt.Sprintf("%s.%.5d.%s", uploadID, part.PartNumber, part.ETag)
+		multipartPartFile := path.Join(mpartMetaPrefix, bucket, object, partSuffix)
 		var fileReader io.ReadCloser
-		fileReader, err = fs.storage.ReadFile(minioMetaBucket, path.Join(bucket, object, partSuffix), 0)
+		fileReader, err = fs.storage.ReadFile(minioMetaBucket, multipartPartFile, 0)
 		if err != nil {
 			if err == errFileNotFound {
-				return "", (InvalidPart{})
+				return "", InvalidPart{}
 			}
 			return "", err
 		}
@@ -387,18 +100,19 @@ func (fs fsObjects) CompleteMultipartUpload(bucket string, object string, upload
 	}
 
 	// Cleanup all the parts.
-	fs.cleanupUploadedParts(bucket, object, uploadID)
+	if err = cleanupUploadedParts(fs.storage, mpartMetaPrefix, bucket, object, uploadID); err != nil {
+		return "", err
+	}
+
+	err = fs.storage.RenameFile(minioMetaBucket, tempObj, bucket, object)
+	if err != nil {
+		return "", toObjectErr(err, bucket, object)
+	}
 
 	// Return md5sum.
 	return s3MD5, nil
 }
 
-// Wrapper to which removes all the uploaded parts after a successful
-// complete multipart upload.
-func (fs fsObjects) cleanupUploadedParts(bucket, object, uploadID string) error {
-	return abortMultipartUploadCommon(fs.storage, bucket, object, uploadID)
-}
-
 // AbortMultipartUpload - aborts a multipart upload.
 func (fs fsObjects) AbortMultipartUpload(bucket, object, uploadID string) error {
 	return abortMultipartUploadCommon(fs.storage, bucket, object, uploadID)

object-common-multipart.go

@@ -23,7 +23,10 @@ import (
 	"io"
 	"io/ioutil"
 	"path"
+	"strconv"
+	"strings"
 
+	"github.com/Sirupsen/logrus"
 	"github.com/skyrings/skyring-common/tools/uuid"
 )
 
@@ -34,7 +37,7 @@ import (
 func newMultipartUploadCommon(storage StorageAPI, bucket string, object string) (uploadID string, err error) {
 	// Verify if bucket name is valid.
 	if !IsValidBucketName(bucket) {
-		return "", (BucketNameInvalid{Bucket: bucket})
+		return "", BucketNameInvalid{Bucket: bucket}
 	}
 	// Verify if object name is valid.
 	if !IsValidObjectName(object) {
@@ -48,15 +51,6 @@ func newMultipartUploadCommon(storage StorageAPI, bucket string, object string)
 		return "", BucketNotFound{Bucket: bucket}
 	}
 
-	if _, err := storage.StatVol(minioMetaBucket); err != nil {
-		if err == errVolumeNotFound {
-			err = storage.MakeVol(minioMetaBucket)
-			if err != nil {
-				return "", toObjectErr(err)
-			}
-		}
-	}
-
 	// Loops through until successfully generates a new unique upload id.
 	for {
 		uuid, err := uuid.New()
@@ -64,19 +58,23 @@ func newMultipartUploadCommon(storage StorageAPI, bucket string, object string)
 			return "", err
 		}
 		uploadID := uuid.String()
-		uploadIDPath := path.Join(bucket, object, uploadID)
+		uploadIDPath := path.Join(mpartMetaPrefix, bucket, object, uploadID)
+		tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
 		if _, err = storage.StatFile(minioMetaBucket, uploadIDPath); err != nil {
 			if err != errFileNotFound {
 				return "", toObjectErr(err, minioMetaBucket, uploadIDPath)
 			}
 			// uploadIDPath doesn't exist, so create empty file to reserve the name
 			var w io.WriteCloser
-			if w, err = storage.CreateFile(minioMetaBucket, uploadIDPath); err == nil {
-				// Close the writer.
-				if err = w.Close(); err != nil {
-					return "", err
-				}
-			} else {
+			if w, err = storage.CreateFile(minioMetaBucket, tempUploadIDPath); err != nil {
+				return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
+			}
+			// Close the writer.
+			if err = w.Close(); err != nil {
+				return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
+			}
+			err = storage.RenameFile(minioMetaBucket, tempUploadIDPath, minioMetaBucket, uploadIDPath)
+			if err != nil {
 				return "", toObjectErr(err, minioMetaBucket, uploadIDPath)
 			}
 			return uploadID, nil
@@ -110,7 +108,7 @@ func putObjectPartCommon(storage StorageAPI, bucket string, object string, uploa
 	}
 
 	partSuffix := fmt.Sprintf("%s.%d", uploadID, partID)
-	partSuffixPath := path.Join(bucket, object, partSuffix)
+	partSuffixPath := path.Join(tmpMetaPrefix, bucket, object, partSuffix)
 	fileWriter, err := storage.CreateFile(minioMetaBucket, partSuffixPath)
 	if err != nil {
 		return "", toObjectErr(err, bucket, object)
@@ -153,28 +151,27 @@ func putObjectPartCommon(storage StorageAPI, bucket string, object string, uploa
 	if err != nil {
 		return "", err
 	}
+
+	partSuffixMD5 := fmt.Sprintf("%s.%.5d.%s", uploadID, partID, newMD5Hex)
+	partSuffixMD5Path := path.Join(mpartMetaPrefix, bucket, object, partSuffixMD5)
+	err = storage.RenameFile(minioMetaBucket, partSuffixPath, minioMetaBucket, partSuffixMD5Path)
+	if err != nil {
+		return "", err
+	}
 	return newMD5Hex, nil
 }
 
-// abortMultipartUploadCommon - aborts a multipart upload, common
-// function used by both object layers.
-func abortMultipartUploadCommon(storage StorageAPI, bucket, object, uploadID string) error {
-	// Verify if bucket is valid.
-	if !IsValidBucketName(bucket) {
-		return BucketNameInvalid{Bucket: bucket}
-	}
-	if !IsValidObjectName(object) {
-		return ObjectNameInvalid{Bucket: bucket, Object: object}
-	}
-	if status, err := isUploadIDExists(storage, bucket, object, uploadID); err != nil {
-		return err
-	} else if !status {
-		return InvalidUploadID{UploadID: uploadID}
-	}
+// Cleanup all temp entries inside tmpMetaPrefix directory, upon server initialization.
+func cleanupAllTmpEntries(storage StorageAPI) error {
+	return cleanupUploadedParts(storage, tmpMetaPrefix, "", "", "")
+}
 
+// Wrapper to which removes all the uploaded parts after a successful
+// complete multipart upload.
+func cleanupUploadedParts(storage StorageAPI, prefix, bucket, object, uploadID string) error {
 	markerPath := ""
 	for {
-		uploadIDPath := path.Join(bucket, object, uploadID)
+		uploadIDPath := path.Join(prefix, bucket, object, uploadID)
 		fileInfos, eof, err := storage.ListFiles(minioMetaBucket, uploadIDPath, markerPath, false, 1000)
 		if err != nil {
 			if err == errFileNotFound {
@@ -192,3 +189,323 @@ func abortMultipartUploadCommon(storage StorageAPI, bucket, object, uploadID str
 	}
 	return nil
 }
+
+// abortMultipartUploadCommon - aborts a multipart upload, common
+// function used by both object layers.
+func abortMultipartUploadCommon(storage StorageAPI, bucket, object, uploadID string) error {
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return BucketNameInvalid{Bucket: bucket}
+	}
+	if !IsValidObjectName(object) {
+		return ObjectNameInvalid{Bucket: bucket, Object: object}
+	}
+	if status, err := isUploadIDExists(storage, bucket, object, uploadID); err != nil {
+		return err
+	} else if !status {
+		return InvalidUploadID{UploadID: uploadID}
+	}
+	return cleanupUploadedParts(storage, mpartMetaPrefix, bucket, object, uploadID)
+}
+
+// listLeafEntries - lists all entries if a given prefixPath is a leaf
+// directory, returns error if any - returns empty list if prefixPath
+// is not a leaf directory.
+func listLeafEntries(storage StorageAPI, prefixPath string) (entries []FileInfo, e error) {
+	var markerPath string
+	for {
+		fileInfos, eof, err := storage.ListFiles(minioMetaBucket, prefixPath, markerPath, false, 1000)
+		if err != nil {
+			log.WithFields(logrus.Fields{
+				"prefixPath": prefixPath,
+				"markerPath": markerPath,
+			}).Errorf("%s", err)
+			return nil, err
+		}
+		for _, fileInfo := range fileInfos {
+			// Set marker for next batch of ListFiles.
+			markerPath = fileInfo.Name
+			if fileInfo.Mode.IsDir() {
+				// If a directory is found, doesn't return anything.
+				return nil, nil
+			}
+			fileName := path.Base(fileInfo.Name)
+			if !strings.Contains(fileName, ".") {
+				// Skip the entry if it is of the pattern bucket/object/uploadID.partNum.md5sum
+				// and retain entries of the pattern bucket/object/uploadID
+				entries = append(entries, fileInfo)
+			}
+		}
+		if eof {
+			break
+		}
+	}
+	return entries, nil
+}
+
+// listMetaBucketMultipartFiles - list all files at a given prefix inside minioMetaBucket.
+func listMetaBucketMultipartFiles(storage StorageAPI, prefixPath string, markerPath string, recursive bool, maxKeys int) (allFileInfos []FileInfo, eof bool, err error) {
+	// newMaxKeys tracks the size of entries which are going to be
+	// returned back.
+	var newMaxKeys int
+
+	// Following loop gathers and filters out special files inside
+	// minio meta volume.
+	for {
+		var fileInfos []FileInfo
+		// List files up to maxKeys-newMaxKeys, since we are skipping
+		// entries for special files.
+		fileInfos, eof, err = storage.ListFiles(minioMetaBucket, prefixPath, markerPath, recursive, maxKeys-newMaxKeys)
+		if err != nil {
+			log.WithFields(logrus.Fields{
+				"prefixPath": prefixPath,
+				"markerPath": markerPath,
+				"recursive":  recursive,
+				"maxKeys":    maxKeys,
+			}).Errorf("%s", err)
+			return nil, true, err
+		}
+		// Loop through and validate individual file.
+		for _, fi := range fileInfos {
+			var entries []FileInfo
+			if fi.Mode.IsDir() {
+				// List all the entries if fi.Name is a leaf directory, if
+				// fi.Name is not a leaf directory then the resulting
+				// entries are empty.
+				entries, err = listLeafEntries(storage, fi.Name)
+				if err != nil {
+					log.WithFields(logrus.Fields{
+						"prefixPath": fi.Name,
+					}).Errorf("%s", err)
+					return nil, false, err
+				}
+			}
+			// Set markerPath for next batch of listing.
+			markerPath = fi.Name
+			if len(entries) > 0 {
+				// We reach here for non-recursive case and a leaf entry.
+				for _, entry := range entries {
+					allFileInfos = append(allFileInfos, entry)
+					newMaxKeys++
+					// If we have reached the maxKeys, it means we have listed
+					// everything that was requested. Return right here.
+					if newMaxKeys == maxKeys {
+						// Return values:
+						// allFileInfos : "maxKeys" number of entries.
+						// eof : eof returned by fs.storage.ListFiles()
+						// error : nil
+						return
+					}
+				}
+			} else {
+				// We reach here for a non-recursive case non-leaf entry
+				// OR recursive case with fi.Name matching pattern bucket/object/uploadID[.partNum.md5sum]
+				if !fi.Mode.IsDir() { // Do not skip non-recursive case directory entries.
+					// Skip files matching pattern bucket/object/uploadID.partNum.md5sum
+					// and retain files matching pattern bucket/object/uploadID
+					specialFile := path.Base(fi.Name)
+					if strings.Contains(specialFile, ".") {
+						// Contains partnumber and md5sum info, skip this.
+						continue
+					}
+				}
+				allFileInfos = append(allFileInfos, fi)
+				newMaxKeys++
+				// If we have reached the maxKeys, it means we have listed
+				// everything that was requested. Return right here.
+				if newMaxKeys == maxKeys {
+					// Return values:
+					// allFileInfos : "maxKeys" number of entries.
+					// eof : eof returned by fs.storage.ListFiles()
+					// error : nil
+					return
+				}
+			}
+		}
+		// If we have reached eof then we break out.
+		if eof {
+			break
+		}
+	}
+
+	// Return entries here.
+	return allFileInfos, eof, nil
+}
+
+// listMultipartUploadsCommon - lists all multipart uploads, common
+// function for both object layers.
+func listMultipartUploadsCommon(storage StorageAPI, bucket, prefix, keyMarker, uploadIDMarker, delimiter string, maxUploads int) (ListMultipartsInfo, error) {
+	result := ListMultipartsInfo{}
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return ListMultipartsInfo{}, BucketNameInvalid{Bucket: bucket}
+	}
+	if !IsValidObjectPrefix(prefix) {
+		return ListMultipartsInfo{}, ObjectNameInvalid{Bucket: bucket, Object: prefix}
+	}
+	// Verify if delimiter is anything other than '/', which we do not support.
+	if delimiter != "" && delimiter != slashSeparator {
+		return ListMultipartsInfo{}, UnsupportedDelimiter{
+			Delimiter: delimiter,
+		}
+	}
+	// Verify if marker has prefix.
+	if keyMarker != "" && !strings.HasPrefix(keyMarker, prefix) {
+		return ListMultipartsInfo{}, InvalidMarkerPrefixCombination{
+			Marker: keyMarker,
+			Prefix: prefix,
+		}
+	}
+	if uploadIDMarker != "" {
+		if strings.HasSuffix(keyMarker, slashSeparator) {
+			return result, InvalidUploadIDKeyCombination{
+				UploadIDMarker: uploadIDMarker,
+				KeyMarker:      keyMarker,
+			}
+		}
+		id, err := uuid.Parse(uploadIDMarker)
+		if err != nil {
+			return result, err
+		}
+		if id.IsZero() {
+			return result, MalformedUploadID{
+				UploadID: uploadIDMarker,
+			}
+		}
+	}
+
+	recursive := true
+	if delimiter == slashSeparator {
+		recursive = false
+	}
+
+	result.IsTruncated = true
+	result.MaxUploads = maxUploads
+
+	// Not using path.Join() as it strips off the trailing '/'.
+	// Also bucket should always be followed by '/' even if prefix is empty.
+	multipartPrefixPath := pathJoin(mpartMetaPrefix, pathJoin(bucket, prefix))
+	multipartMarkerPath := ""
+	if keyMarker != "" {
+		keyMarkerPath := pathJoin(pathJoin(bucket, keyMarker), uploadIDMarker)
+		multipartMarkerPath = pathJoin(mpartMetaPrefix, keyMarkerPath)
+	}
+
+	// List all the multipart files at prefixPath, starting with marker keyMarkerPath.
+	fileInfos, eof, err := listMetaBucketMultipartFiles(storage, multipartPrefixPath, multipartMarkerPath, recursive, maxUploads)
+	if err != nil {
+		log.WithFields(logrus.Fields{
+			"prefixPath": multipartPrefixPath,
+			"markerPath": multipartMarkerPath,
+			"recursive":  recursive,
+			"maxUploads": maxUploads,
+		}).Errorf("listMetaBucketMultipartFiles failed with %s", err)
+		return ListMultipartsInfo{}, err
+	}
+
+	// Loop through all the received files fill in the multiparts result.
+	for _, fi := range fileInfos {
+		var objectName string
+		var uploadID string
+		if fi.Mode.IsDir() {
+			// All directory entries are common prefixes.
+			uploadID = "" // Upload ids are empty for CommonPrefixes.
+			objectName = strings.TrimPrefix(fi.Name, retainSlash(path.Join(mpartMetaPrefix, bucket)))
+			result.CommonPrefixes = append(result.CommonPrefixes, objectName)
+		} else {
+			uploadID = path.Base(fi.Name)
+			objectName = strings.TrimPrefix(path.Dir(fi.Name), retainSlash(path.Join(mpartMetaPrefix, bucket)))
+			result.Uploads = append(result.Uploads, uploadMetadata{
+				Object:    objectName,
+				UploadID:  uploadID,
+				Initiated: fi.ModTime,
+			})
+		}
+		result.NextKeyMarker = objectName
+		result.NextUploadIDMarker = uploadID
+	}
+	result.IsTruncated = !eof
+	if !result.IsTruncated {
+		result.NextKeyMarker = ""
+		result.NextUploadIDMarker = ""
+	}
+	return result, nil
+}
+
+// ListObjectParts - list object parts, common function across both
+// object layers.
+func listObjectPartsCommon(storage StorageAPI, bucket, object, uploadID string, partNumberMarker, maxParts int) (ListPartsInfo, error) {
+	// Verify if bucket is valid.
+	if !IsValidBucketName(bucket) {
+		return ListPartsInfo{}, BucketNameInvalid{Bucket: bucket}
+	}
+	if !IsValidObjectName(object) {
+		return ListPartsInfo{}, ObjectNameInvalid{Bucket: bucket, Object: object}
+	}
+	if status, err := isUploadIDExists(storage, bucket, object, uploadID); err != nil {
+		return ListPartsInfo{}, err
+	} else if !status {
+		return ListPartsInfo{}, InvalidUploadID{UploadID: uploadID}
+	}
+	result := ListPartsInfo{}
+	var markerPath string
+	nextPartNumberMarker := 0
+	uploadIDPath := path.Join(mpartMetaPrefix, bucket, object, uploadID)
+	// Figure out the marker for the next subsequent calls, if the
+	// partNumberMarker is already set.
+	if partNumberMarker > 0 {
+		partNumberMarkerPath := uploadIDPath + "." + fmt.Sprintf("%.5d", partNumberMarker) + "."
+		fileInfos, _, err := storage.ListFiles(minioMetaBucket, partNumberMarkerPath, "", false, 1)
+		if err != nil {
+			return result, toObjectErr(err, minioMetaBucket, partNumberMarkerPath)
+		}
+		if len(fileInfos) == 0 {
+			return result, InvalidPart{}
+		}
+		markerPath = fileInfos[0].Name
+	}
+	uploadIDPrefix := uploadIDPath + "."
+	fileInfos, eof, err := storage.ListFiles(minioMetaBucket, uploadIDPrefix, markerPath, false, maxParts)
+	if err != nil {
+		return result, InvalidPart{}
+	}
+	for _, fileInfo := range fileInfos {
+		fileName := path.Base(fileInfo.Name)
+		splitResult := strings.Split(fileName, ".")
+		partNum, err := strconv.Atoi(splitResult[1])
+		if err != nil {
+			return result, err
+		}
+		md5sum := splitResult[2]
+		result.Parts = append(result.Parts, partInfo{
+			PartNumber:   partNum,
+			LastModified: fileInfo.ModTime,
+			ETag:         md5sum,
+			Size:         fileInfo.Size,
+		})
+		nextPartNumberMarker = partNum
+	}
+	result.Bucket = bucket
+	result.Object = object
+	result.UploadID = uploadID
+	result.PartNumberMarker = partNumberMarker
+	result.NextPartNumberMarker = nextPartNumberMarker
+	result.MaxParts = maxParts
+	result.IsTruncated = !eof
+	return result, nil
+}
+
+// isUploadIDExists - verify if a given uploadID exists and is valid.
+func isUploadIDExists(storage StorageAPI, bucket, object, uploadID string) (bool, error) {
+	uploadIDPath := path.Join(mpartMetaPrefix, bucket, object, uploadID)
+	st, err := storage.StatFile(minioMetaBucket, uploadIDPath)
+	if err != nil {
+		// Upload id does not exist.
+		if err == errFileNotFound {
+			return false, nil
+		}
+		return false, err
+	}
+	// Upload id exists and is a regular file.
+	return st.Mode.IsRegular(), nil
+}

object-common.go

@@ -105,13 +105,13 @@ func deleteBucket(storage StorageAPI, bucket string) error {
 func putObjectCommon(storage StorageAPI, bucket string, object string, size int64, data io.Reader, metadata map[string]string) (string, error) {
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
-		return "", (BucketNameInvalid{Bucket: bucket})
+		return "", BucketNameInvalid{Bucket: bucket}
 	}
 	if !IsValidObjectName(object) {
-		return "", (ObjectNameInvalid{
+		return "", ObjectNameInvalid{
 			Bucket: bucket,
 			Object: object,
-		})
+		}
 	}
 	// Check whether the bucket exists.
 	if isExist, err := isBucketExist(storage, bucket); err != nil {
@@ -120,7 +120,8 @@ func putObjectCommon(storage StorageAPI, bucket string, object string, size int6
 		return "", BucketNotFound{Bucket: bucket}
 	}
 
-	fileWriter, err := storage.CreateFile(bucket, object)
+	tempObj := path.Join(tmpMetaPrefix, bucket, object)
+	fileWriter, err := storage.CreateFile(minioMetaBucket, tempObj)
 	if err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
@@ -166,26 +167,15 @@ func putObjectCommon(storage StorageAPI, bucket string, object string, size int6
 	if err != nil {
 		return "", err
 	}
+	err = storage.RenameFile(minioMetaBucket, tempObj, bucket, object)
+	if err != nil {
+		return "", err
+	}
 
 	// Return md5sum, successfully wrote object.
 	return newMD5Hex, nil
 }
 
-// isUploadIDExists - verify if a given uploadID exists and is valid.
-func isUploadIDExists(storage StorageAPI, bucket, object, uploadID string) (bool, error) {
-	uploadIDPath := path.Join(bucket, object, uploadID)
-	st, err := storage.StatFile(minioMetaBucket, uploadIDPath)
-	if err != nil {
-		// Upload id does not exist.
-		if err == errFileNotFound {
-			return false, nil
-		}
-		return false, err
-	}
-	// Upload id exists and is a regular file.
-	return st.Mode.IsRegular(), nil
-}
-
 // checks whether bucket exists.
 func isBucketExist(storage StorageAPI, bucketName string) (bool, error) {
 	// Check whether bucket exists.

object-utils.go

@@ -32,6 +32,10 @@ import (
 const (
 	// Minio meta bucket.
 	minioMetaBucket = ".minio"
+	// Multipart meta prefix.
+	mpartMetaPrefix = "multipart"
+	// Tmp meta prefix.
+	tmpMetaPrefix = "tmp"
 )
 
 // validBucket regexp.

posix.go

@@ -741,7 +741,7 @@ func (s fsStorage) RenameFile(srcVolume, srcPath, dstVolume, dstPath string) err
 		log.WithFields(logrus.Fields{
 			"diskPath": s.diskPath,
 			"volume":   srcVolume,
-		}).Debugf("getVolumeDir failed with %s", err)
+		}).Errorf("getVolumeDir failed with %s", err)
 		return err
 	}
 	dstVolumeDir, err := s.getVolumeDir(dstVolume)
@@ -749,12 +749,20 @@ func (s fsStorage) RenameFile(srcVolume, srcPath, dstVolume, dstPath string) err
 		log.WithFields(logrus.Fields{
 			"diskPath": s.diskPath,
 			"volume":   dstVolume,
-		}).Debugf("getVolumeDir failed with %s", err)
+		}).Errorf("getVolumeDir failed with %s", err)
 		return err
 	}
 	if err = os.MkdirAll(path.Join(dstVolumeDir, path.Dir(dstPath)), 0755); err != nil {
-		log.Debug("os.MkdirAll failed with %s", err)
+		log.Errorf("os.MkdirAll failed with %s", err)
 		return err
 	}
-	return os.Rename(path.Join(srcVolumeDir, srcPath), path.Join(dstVolumeDir, dstPath))
+	err = os.Rename(path.Join(srcVolumeDir, srcPath), path.Join(dstVolumeDir, dstPath))
+	if err != nil {
+		if os.IsNotExist(err) {
+			return errFileNotFound
+		}
+		log.Errorf("os.Rename failed with %s", err)
+		return err
+	}
+	return nil
 }

xl-erasure-v1.go

@@ -697,17 +697,22 @@ func (xl XL) DeleteFile(volume, path string) error {
 	// find online disks and meta data of higherVersion
 	var mdata *xlMetaV1
 	onlineDiskCount := 0
+	errFileNotFoundErr := 0
 	for index, metadata := range partsMetadata {
 		if errs[index] == nil {
 			onlineDiskCount++
 			if metadata.Stat.Version == higherVersion && mdata == nil {
 				mdata = &metadata
 			}
+		} else if errs[index] == errFileNotFound {
+			errFileNotFoundErr++
 		}
 	}
 
-	// return error if mdata is empty or onlineDiskCount doesn't meet write quorum
-	if mdata == nil || onlineDiskCount < xl.writeQuorum {
+	if errFileNotFoundErr == len(xl.storageDisks) {
+		return errFileNotFound
+	} else if mdata == nil || onlineDiskCount < xl.writeQuorum {
+		// return error if mdata is empty or onlineDiskCount doesn't meet write quorum
 		return errWriteQuorum
 	}
 
@@ -768,7 +773,22 @@ func (xl XL) DeleteFile(volume, path string) error {
 			if errCount <= len(xl.storageDisks)-xl.writeQuorum {
 				continue
 			}
-
+			// Safely close and remove.
+			if err = safeCloseAndRemove(metadataWriter); err != nil {
+				return err
+			}
+			return err
+		}
+		// Safely wrote, now rename to its actual location.
+		if err = metadataWriter.Close(); err != nil {
+			log.WithFields(logrus.Fields{
+				"volume":    volume,
+				"path":      path,
+				"diskIndex": index,
+			}).Errorf("Metadata commit failed with %s", err)
+			if err = safeCloseAndRemove(metadataWriter); err != nil {
+				return err
+			}
 			return err
 		}
 
@@ -810,7 +830,7 @@ func (xl XL) DeleteFile(volume, path string) error {
 			}
 		}
 	}
-
+	// Return success.
 	return nil
 }
 
@@ -829,14 +849,47 @@ func (xl XL) RenameFile(srcVolume, srcPath, dstVolume, dstPath string) error {
 	if !isValidPath(dstPath) {
 		return errInvalidArgument
 	}
-	for _, disk := range xl.storageDisks {
-		if err := disk.RenameFile(srcVolume, srcPath, dstVolume, dstPath); err != nil {
+
+	// Hold read lock at source before rename.
+	nsMutex.RLock(srcVolume, srcPath)
+	defer nsMutex.RUnlock(srcVolume, srcPath)
+
+	// Hold write lock at destination before rename.
+	nsMutex.Lock(dstVolume, dstPath)
+	defer nsMutex.Unlock(dstVolume, dstPath)
+
+	for index, disk := range xl.storageDisks {
+		// Make sure to rename all the files only, not directories.
+		srcErasurePartPath := slashpath.Join(srcPath, fmt.Sprintf("file.%d", index))
+		dstErasurePartPath := slashpath.Join(dstPath, fmt.Sprintf("file.%d", index))
+		err := disk.RenameFile(srcVolume, srcErasurePartPath, dstVolume, dstErasurePartPath)
+		if err != nil {
+			log.WithFields(logrus.Fields{
+				"srcVolume": srcVolume,
+				"srcPath":   srcErasurePartPath,
+				"dstVolume": dstVolume,
+				"dstPath":   dstErasurePartPath,
+			}).Errorf("RenameFile failed with %s", err)
+			return err
+		}
+		srcXLMetaPath := slashpath.Join(srcPath, xlMetaV1File)
+		dstXLMetaPath := slashpath.Join(dstPath, xlMetaV1File)
+		err = disk.RenameFile(srcVolume, srcXLMetaPath, dstVolume, dstXLMetaPath)
+		if err != nil {
+			log.WithFields(logrus.Fields{
+				"srcVolume": srcVolume,
+				"srcPath":   srcXLMetaPath,
+				"dstVolume": dstVolume,
+				"dstPath":   dstXLMetaPath,
+			}).Errorf("RenameFile failed with %s", err)
+			return err
+		}
+		err = disk.DeleteFile(srcVolume, srcPath)
+		if err != nil {
 			log.WithFields(logrus.Fields{
 				"srcVolume": srcVolume,
 				"srcPath":   srcPath,
-				"dstVolume": dstVolume,
-				"dstPath":   dstPath,
-			}).Errorf("RenameFile failed with %s", err)
+			}).Errorf("DeleteFile failed with %s", err)
 			return err
 		}
 	}

xl-objects-multipart.go

@@ -21,12 +21,6 @@ import (
 	"fmt"
 	"io"
 	"path"
-	"sort"
-	"strconv"
-	"strings"
-
-	"github.com/Sirupsen/logrus"
-	"github.com/skyrings/skyring-common/tools/uuid"
 )
 
 // MultipartPartInfo Info of each part kept in the multipart metadata file after
@@ -68,224 +62,9 @@ func partNumToPartFileName(partNum int) string {
 	return fmt.Sprintf("%.5d%s", partNum, multipartSuffix)
 }
 
-// listLeafEntries - lists all entries if a given prefixPath is a leaf
-// directory, returns error if any - returns empty list if prefixPath
-// is not a leaf directory.
-func (xl xlObjects) listLeafEntries(prefixPath string) (entries []FileInfo, e error) {
-	var markerPath string
-	for {
-		fileInfos, eof, err := xl.storage.ListFiles(minioMetaBucket, prefixPath, markerPath, false, 1000)
-		if err != nil {
-			log.WithFields(logrus.Fields{
-				"prefixPath": prefixPath,
-				"markerPath": markerPath,
-			}).Errorf("%s", err)
-			return nil, err
-		}
-		for _, fileInfo := range fileInfos {
-			// Set marker for next batch of ListFiles.
-			markerPath = fileInfo.Name
-			if fileInfo.Mode.IsDir() {
-				// If a directory is found, doesn't return anything.
-				return nil, nil
-			}
-			fileName := path.Base(fileInfo.Name)
-			if !strings.Contains(fileName, ".") {
-				// Skip the entry if it is of the pattern bucket/object/uploadID.partNum.md5sum
-				// and retain entries of the pattern bucket/object/uploadID
-				entries = append(entries, fileInfo)
-			}
-		}
-		if eof {
-			break
-		}
-	}
-	return entries, nil
-}
-
-// listMetaBucketFiles - list all files at a given prefix inside minioMetaBucket.
-func (xl xlObjects) listMetaBucketFiles(prefixPath string, markerPath string, recursive bool, maxKeys int) (allFileInfos []FileInfo, eof bool, err error) {
-	// newMaxKeys tracks the size of entries which are going to be
-	// returned back.
-	var newMaxKeys int
-
-	// Following loop gathers and filters out special files inside
-	// minio meta volume.
-	for {
-		var fileInfos []FileInfo
-		// List files up to maxKeys-newMaxKeys, since we are skipping entries for special files.
-		fileInfos, eof, err = xl.storage.ListFiles(minioMetaBucket, prefixPath, markerPath, recursive, maxKeys-newMaxKeys)
-		if err != nil {
-			log.WithFields(logrus.Fields{
-				"prefixPath": prefixPath,
-				"markerPath": markerPath,
-				"recursive":  recursive,
-				"maxKeys":    maxKeys,
-			}).Errorf("%s", err)
-			return nil, true, err
-		}
-		// Loop through and validate individual file.
-		for _, fi := range fileInfos {
-			var entries []FileInfo
-			if fi.Mode.IsDir() {
-				// List all the entries if fi.Name is a leaf directory, if
-				// fi.Name is not a leaf directory then the resulting
-				// entries are empty.
-				entries, err = xl.listLeafEntries(fi.Name)
-				if err != nil {
-					log.WithFields(logrus.Fields{
-						"prefixPath": fi.Name,
-					}).Errorf("%s", err)
-					return nil, false, err
-				}
-			}
-			// Set markerPath for next batch of listing.
-			markerPath = fi.Name
-			if len(entries) > 0 {
-				// We reach here for non-recursive case and a leaf entry.
-				for _, entry := range entries {
-					allFileInfos = append(allFileInfos, entry)
-					newMaxKeys++
-					// If we have reached the maxKeys, it means we have listed
-					// everything that was requested. Return right here.
-					if newMaxKeys == maxKeys {
-						// Return values:
-						// allFileInfos : "maxKeys" number of entries.
-						// eof : eof returned by xl.storage.ListFiles()
-						// error : nil
-						return
-					}
-				}
-			} else {
-				// We reach here for a non-recursive case non-leaf entry
-				// OR recursive case with fi.Name matching pattern bucket/object/uploadID[.partNum.md5sum]
-				if !fi.Mode.IsDir() { // Do not skip non-recursive case directory entries.
-					// Skip files matching pattern bucket/object/uploadID.partNum.md5sum
-					// and retain files matching pattern bucket/object/uploadID
-					specialFile := path.Base(fi.Name)
-					if strings.Contains(specialFile, ".") {
-						// Contains partnumber and md5sum info, skip this.
-						continue
-					}
-				}
-			}
-			allFileInfos = append(allFileInfos, fi)
-			newMaxKeys++
-			// If we have reached the maxKeys, it means we have listed
-			// everything that was requested. Return right here.
-			if newMaxKeys == maxKeys {
-				// Return values:
-				// allFileInfos : "maxKeys" number of entries.
-				// eof : eof returned by xl.storage.ListFiles()
-				// error : nil
-				return
-			}
-		}
-		// If we have reached eof then we break out.
-		if eof {
-			break
-		}
-	}
-
-	// Return entries here.
-	return allFileInfos, eof, nil
-}
-
 // ListMultipartUploads - list multipart uploads.
 func (xl xlObjects) ListMultipartUploads(bucket, prefix, keyMarker, uploadIDMarker, delimiter string, maxUploads int) (ListMultipartsInfo, error) {
-	result := ListMultipartsInfo{}
-	// Verify if bucket is valid.
-	if !IsValidBucketName(bucket) {
-		return ListMultipartsInfo{}, (BucketNameInvalid{Bucket: bucket})
-	}
-	if !IsValidObjectPrefix(prefix) {
-		return ListMultipartsInfo{}, (ObjectNameInvalid{Bucket: bucket, Object: prefix})
-	}
-	// Verify if delimiter is anything other than '/', which we do not support.
-	if delimiter != "" && delimiter != slashSeparator {
-		return ListMultipartsInfo{}, (UnsupportedDelimiter{
-			Delimiter: delimiter,
-		})
-	}
-	// Verify if marker has prefix.
-	if keyMarker != "" && !strings.HasPrefix(keyMarker, prefix) {
-		return ListMultipartsInfo{}, (InvalidMarkerPrefixCombination{
-			Marker: keyMarker,
-			Prefix: prefix,
-		})
-	}
-	if uploadIDMarker != "" {
-		if strings.HasSuffix(keyMarker, slashSeparator) {
-			return result, (InvalidUploadIDKeyCombination{
-				UploadIDMarker: uploadIDMarker,
-				KeyMarker:      keyMarker,
-			})
-		}
-		id, err := uuid.Parse(uploadIDMarker)
-		if err != nil {
-			return result, err
-		}
-		if id.IsZero() {
-			return result, (MalformedUploadID{
-				UploadID: uploadIDMarker,
-			})
-		}
-	}
-
-	recursive := true
-	if delimiter == slashSeparator {
-		recursive = false
-	}
-
-	result.IsTruncated = true
-	result.MaxUploads = maxUploads
-
-	// Not using path.Join() as it strips off the trailing '/'.
-	// Also bucket should always be followed by '/' even if prefix is empty.
-	prefixPath := pathJoin(bucket, prefix)
-	keyMarkerPath := ""
-	if keyMarker != "" {
-		keyMarkerPath = pathJoin(pathJoin(bucket, keyMarker), uploadIDMarker)
-	}
-	// List all the multipart files at prefixPath, starting with marker keyMarkerPath.
-	fileInfos, eof, err := xl.listMetaBucketFiles(prefixPath, keyMarkerPath, recursive, maxUploads)
-	if err != nil {
-		log.WithFields(logrus.Fields{
-			"prefixPath": prefixPath,
-			"markerPath": keyMarkerPath,
-			"recursive":  recursive,
-			"maxUploads": maxUploads,
-		}).Errorf("listMetaBucketFiles failed with %s", err)
-		return ListMultipartsInfo{}, err
-	}
-
-	// Loop through all the received files fill in the multiparts result.
-	for _, fi := range fileInfos {
-		var objectName string
-		var uploadID string
-		if fi.Mode.IsDir() {
-			// All directory entries are common prefixes.
-			uploadID = "" // Upload ids are empty for CommonPrefixes.
-			objectName = strings.TrimPrefix(fi.Name, retainSlash(bucket))
-			result.CommonPrefixes = append(result.CommonPrefixes, objectName)
-		} else {
-			uploadID = path.Base(fi.Name)
-			objectName = strings.TrimPrefix(path.Dir(fi.Name), retainSlash(bucket))
-			result.Uploads = append(result.Uploads, uploadMetadata{
-				Object:    objectName,
-				UploadID:  uploadID,
-				Initiated: fi.ModTime,
-			})
-		}
-		result.NextKeyMarker = objectName
-		result.NextUploadIDMarker = uploadID
-	}
-	result.IsTruncated = !eof
-	if !result.IsTruncated {
-		result.NextKeyMarker = ""
-		result.NextUploadIDMarker = ""
-	}
-	return result, nil
+	return listMultipartUploadsCommon(xl.storage, bucket, prefix, keyMarker, uploadIDMarker, delimiter, maxUploads)
 }
 
 // NewMultipartUpload - initialize a new multipart upload, returns a unique id.
@@ -295,113 +74,46 @@ func (xl xlObjects) NewMultipartUpload(bucket, object string) (string, error) {
 
 // PutObjectPart - writes the multipart upload chunks.
 func (xl xlObjects) PutObjectPart(bucket, object, uploadID string, partID int, size int64, data io.Reader, md5Hex string) (string, error) {
-	newMD5Hex, err := putObjectPartCommon(xl.storage, bucket, object, uploadID, partID, size, data, md5Hex)
-	if err != nil {
-		return "", err
-	}
-	partSuffix := fmt.Sprintf("%s.%d", uploadID, partID)
-	partSuffixPath := path.Join(bucket, object, partSuffix)
-	partSuffixMD5 := fmt.Sprintf("%s.%.5d.%s", uploadID, partID, newMD5Hex)
-	partSuffixMD5Path := path.Join(bucket, object, partSuffixMD5)
-	err = xl.storage.RenameFile(minioMetaBucket, partSuffixPath, minioMetaBucket, partSuffixMD5Path)
-	if err != nil {
-		return "", err
-	}
-	return newMD5Hex, nil
+	return putObjectPartCommon(xl.storage, bucket, object, uploadID, partID, size, data, md5Hex)
 }
 
+// ListObjectParts - list object parts.
 func (xl xlObjects) ListObjectParts(bucket, object, uploadID string, partNumberMarker, maxParts int) (ListPartsInfo, error) {
-	// Verify if bucket is valid.
-	if !IsValidBucketName(bucket) {
-		return ListPartsInfo{}, (BucketNameInvalid{Bucket: bucket})
-	}
-	if !IsValidObjectName(object) {
-		return ListPartsInfo{}, (ObjectNameInvalid{Bucket: bucket, Object: object})
-	}
-	if status, err := isUploadIDExists(xl.storage, bucket, object, uploadID); err != nil {
-		return ListPartsInfo{}, err
-	} else if !status {
-		return ListPartsInfo{}, (InvalidUploadID{UploadID: uploadID})
-	}
-	result := ListPartsInfo{}
-	var markerPath string
-	nextPartNumberMarker := 0
-	uploadIDPath := path.Join(bucket, object, uploadID)
-	// Figure out the marker for the next subsequent calls, if the
-	// partNumberMarker is already set.
-	if partNumberMarker > 0 {
-		partNumberMarkerPath := uploadIDPath + "." + fmt.Sprintf("%.5d", partNumberMarker) + "."
-		fileInfos, _, err := xl.storage.ListFiles(minioMetaBucket, partNumberMarkerPath, "", false, 1)
-		if err != nil {
-			return result, toObjectErr(err, minioMetaBucket, partNumberMarkerPath)
-		}
-		if len(fileInfos) == 0 {
-			return result, (InvalidPart{})
-		}
-		markerPath = fileInfos[0].Name
-	}
-	uploadIDPrefix := uploadIDPath + "."
-	fileInfos, eof, err := xl.storage.ListFiles(minioMetaBucket, uploadIDPrefix, markerPath, false, maxParts)
-	if err != nil {
-		return result, InvalidPart{}
-	}
-	for _, fileInfo := range fileInfos {
-		fileName := path.Base(fileInfo.Name)
-		splitResult := strings.Split(fileName, ".")
-		partNum, err := strconv.Atoi(splitResult[1])
-		if err != nil {
-			return result, err
-		}
-		md5sum := splitResult[2]
-		result.Parts = append(result.Parts, partInfo{
-			PartNumber:   partNum,
-			LastModified: fileInfo.ModTime,
-			ETag:         md5sum,
-			Size:         fileInfo.Size,
-		})
-		nextPartNumberMarker = partNum
-	}
-	result.Bucket = bucket
-	result.Object = object
-	result.UploadID = uploadID
-	result.PartNumberMarker = partNumberMarker
-	result.NextPartNumberMarker = nextPartNumberMarker
-	result.MaxParts = maxParts
-	result.IsTruncated = !eof
-	return result, nil
+	return listObjectPartsCommon(xl.storage, bucket, object, uploadID, partNumberMarker, maxParts)
 }
 
 func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, uploadID string, parts []completePart) (string, error) {
 	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
-		return "", (BucketNameInvalid{Bucket: bucket})
+		return "", BucketNameInvalid{Bucket: bucket}
 	}
 	if !IsValidObjectName(object) {
-		return "", (ObjectNameInvalid{
+		return "", ObjectNameInvalid{
 			Bucket: bucket,
 			Object: object,
-		})
+		}
 	}
 	if status, err := isUploadIDExists(xl.storage, bucket, object, uploadID); err != nil {
 		return "", err
 	} else if !status {
-		return "", (InvalidUploadID{UploadID: uploadID})
+		return "", InvalidUploadID{UploadID: uploadID}
 	}
-	sort.Sort(completedParts(parts))
 	var metadata MultipartObjectInfo
-	for _, part := range parts {
-		partSuffix := fmt.Sprintf("%s.%.5d.%s", uploadID, part.PartNumber, part.ETag)
-		fi, err := xl.storage.StatFile(minioMetaBucket, path.Join(bucket, object, partSuffix))
-		if err != nil {
-			return "", err
-		}
-		metadata = append(metadata, MultipartPartInfo{part.PartNumber, part.ETag, fi.Size})
-	}
 	var md5Sums []string
 	for _, part := range parts {
 		// Construct part suffix.
 		partSuffix := fmt.Sprintf("%s.%.5d.%s", uploadID, part.PartNumber, part.ETag)
-		err := xl.storage.RenameFile(minioMetaBucket, path.Join(bucket, object, partSuffix), bucket, path.Join(object, partNumToPartFileName(part.PartNumber)))
+		multipartPartFile := path.Join(mpartMetaPrefix, bucket, object, partSuffix)
+		fi, err := xl.storage.StatFile(minioMetaBucket, multipartPartFile)
+		if err != nil {
+			if err == errFileNotFound {
+				return "", InvalidPart{}
+			}
+			return "", err
+		}
+		metadata = append(metadata, MultipartPartInfo{part.PartNumber, part.ETag, fi.Size})
+		multipartObjSuffix := path.Join(object, partNumToPartFileName(part.PartNumber))
+		err = xl.storage.RenameFile(minioMetaBucket, multipartPartFile, bucket, multipartObjSuffix)
 		// We need a way to roll back if of the renames failed.
 		if err != nil {
 			return "", err
@@ -409,31 +121,33 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 		md5Sums = append(md5Sums, part.ETag)
 	}
 
-	if w, err := xl.storage.CreateFile(bucket, pathJoin(object, multipartMetaFile)); err == nil {
-		var b []byte
-		b, err = json.Marshal(metadata)
-		if err != nil {
-			return "", err
-		}
-		_, err = w.Write(b)
-		if err != nil {
-			return "", err
-		}
-		// Close the writer.
-		if err = w.Close(); err != nil {
-			return "", err
-		}
-	} else {
+	tempMultipartMetaFile := path.Join(tmpMetaPrefix, bucket, object, multipartMetaFile)
+	w, err := xl.storage.CreateFile(minioMetaBucket, tempMultipartMetaFile)
+	if err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
-	if err := xl.storage.DeleteFile(minioMetaBucket, path.Join(bucket, object, uploadID)); err != nil {
-		return "", toObjectErr(err, bucket, object)
+	encoder := json.NewEncoder(w)
+	err = encoder.Encode(&metadata)
+	if err != nil {
+		if err = safeCloseAndRemove(w); err != nil {
+			return "", err
+		}
+		return "", err
+	}
+	// Close the writer.
+	if err = w.Close(); err != nil {
+		return "", err
 	}
 	// Save the s3 md5.
 	s3MD5, err := makeS3MD5(md5Sums...)
 	if err != nil {
 		return "", err
 	}
+	multipartObjFile := path.Join(object, multipartMetaFile)
+	err = xl.storage.RenameFile(minioMetaBucket, tempMultipartMetaFile, bucket, multipartObjFile)
+	if err != nil {
+		return "", toObjectErr(err, bucket, multipartObjFile)
+	}
 
 	// Return md5sum.
 	return s3MD5, nil