XL: Truly use unique id's in temp directory. (#1790)

This also helps in avoiding cleaning up directories after.

Additionally this patch also fixes the problem of Range offsets.

fs-v1-multipart.go

@@ -76,7 +76,7 @@ func (fs fsObjects) newMultipartUploadCommon(bucket string, object string, meta
 		return "", err
 	}
 	uploadIDPath := path.Join(mpartMetaPrefix, bucket, object, uploadID)
-	tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	tempUploadIDPath := path.Join(tmpMetaPrefix, uploadID)
 	if err = fs.writeFSMetadata(minioMetaBucket, tempUploadIDPath, fsMeta); err != nil {
 		return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
 	}
@@ -300,7 +300,7 @@ func (fs fsObjects) putObjectPartCommon(bucket string, object string, uploadID s
 	defer nsMutex.Unlock(minioMetaBucket, pathJoin(mpartMetaPrefix, bucket, object, uploadID, strconv.Itoa(partID)))
 
 	partSuffix := fmt.Sprintf("object%d", partID)
-	tmpPartPath := path.Join(tmpMetaPrefix, bucket, object, uploadID, partSuffix)
+	tmpPartPath := path.Join(tmpMetaPrefix, uploadID, partSuffix)
 
 	// Initialize md5 writer.
 	md5Writer := md5.New()
@@ -348,7 +348,7 @@ func (fs fsObjects) putObjectPartCommon(bucket string, object string, uploadID s
 		return "", toObjectErr(err, minioMetaBucket, partPath)
 	}
 	uploadIDPath = path.Join(mpartMetaPrefix, bucket, object, uploadID)
-	tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	tempUploadIDPath := path.Join(tmpMetaPrefix, uploadID)
 	if err = fs.writeFSMetadata(minioMetaBucket, tempUploadIDPath, fsMeta); err != nil {
 		return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
 	}
@@ -475,7 +475,7 @@ func (fs fsObjects) CompleteMultipartUpload(bucket string, object string, upload
 		return "", err
 	}
 
-	tempObj := path.Join(tmpMetaPrefix, bucket, object, uploadID, "object1")
+	tempObj := path.Join(tmpMetaPrefix, uploadID, "object1")
 	var buffer = make([]byte, blockSize)
 
 	// Loop through all parts, validate them and then commit to disk.

fs-v1.go

@@ -229,8 +229,10 @@ func (fs fsObjects) PutObject(bucket string, object string, size int64, data io.
 		}
 	}
 
+	uniqueID := getUUID()
+
 	// Temporary object.
-	tempObj := path.Join(tmpMetaPrefix, bucket, object)
+	tempObj := path.Join(tmpMetaPrefix, uniqueID)
 
 	// Initialize md5 writer.
 	md5Writer := md5.New()

xl-v1-metadata.go

@@ -140,8 +140,8 @@ func (xl xlObjects) readXLMetadata(bucket, object string) (xlMeta xlMetaV1, err
 	// Count for errors encountered.
 	var xlJSONErrCount = 0
 
-	// Allocate 4MB buffer.
+	// Allocate 4MiB buffer.
-	var buffer = make([]byte, blockSize)
+	buffer := make([]byte, blockSize)
 
 	// Return the first successful lookup from a random list of disks.
 	for xlJSONErrCount < len(xl.storageDisks) {
@@ -173,6 +173,7 @@ func newXLMetaV1(dataBlocks, parityBlocks int) (xlMeta xlMetaV1) {
 	return xlMeta
 }
 
+// renameXLMetadata - renames `xl.json` from source prefix to destination prefix.
 func (xl xlObjects) renameXLMetadata(srcBucket, srcPrefix, dstBucket, dstPrefix string) error {
 	var wg = &sync.WaitGroup{}
 	var mErrs = make([]error, len(xl.storageDisks))
@@ -185,11 +186,18 @@ func (xl xlObjects) renameXLMetadata(srcBucket, srcPrefix, dstBucket, dstPrefix
 		// Rename `xl.json` in a routine.
 		go func(index int, disk StorageAPI) {
 			defer wg.Done()
+			// Renames `xl.json` from source prefix to destination prefix.
 			rErr := disk.RenameFile(srcBucket, srcJSONFile, dstBucket, dstJSONFile)
 			if rErr != nil {
 				mErrs[index] = rErr
 				return
 			}
+			// Delete any dangling directories.
+			dErr := disk.DeleteFile(srcBucket, srcPrefix)
+			if dErr != nil {
+				mErrs[index] = dErr
+				return
+			}
 			mErrs[index] = nil
 		}(index, disk)
 	}

xl-v1-multipart-common.go

@@ -114,7 +114,8 @@ func readUploadsJSON(bucket, object string, storageDisks ...StorageAPI) (uploadI
 // uploadUploadsJSON - update `uploads.json` with new uploadsJSON for all disks.
 func updateUploadsJSON(bucket, object string, uploadsJSON uploadsV1, storageDisks ...StorageAPI) error {
 	uploadsPath := path.Join(mpartMetaPrefix, bucket, object, uploadsJSONFile)
-	tmpUploadsPath := path.Join(tmpMetaPrefix, bucket, object, uploadsJSONFile)
+	uniqueID := getUUID()
+	tmpUploadsPath := path.Join(tmpMetaPrefix, uniqueID)
 	var errs = make([]error, len(storageDisks))
 	var wg = &sync.WaitGroup{}
 
@@ -169,7 +170,8 @@ func newUploadsV1(format string) uploadsV1 {
 // writeUploadJSON - create `uploads.json` or update it with new uploadID.
 func writeUploadJSON(bucket, object, uploadID string, initiated time.Time, storageDisks ...StorageAPI) (err error) {
 	uploadsPath := path.Join(mpartMetaPrefix, bucket, object, uploadsJSONFile)
-	tmpUploadsPath := path.Join(tmpMetaPrefix, bucket, object, uploadsJSONFile)
+	uniqueID := getUUID()
+	tmpUploadsPath := path.Join(tmpMetaPrefix, uniqueID)
 
 	var errs = make([]error, len(storageDisks))
 	var wg = &sync.WaitGroup{}

xl-v1-multipart.go

@@ -82,7 +82,7 @@ func (xl xlObjects) newMultipartUploadCommon(bucket string, object string, meta
 		return "", err
 	}
 	uploadIDPath := path.Join(mpartMetaPrefix, bucket, object, uploadID)
-	tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	tempUploadIDPath := path.Join(tmpMetaPrefix, uploadID)
 	if err = xl.writeXLMetadata(minioMetaBucket, tempUploadIDPath, xlMeta); err != nil {
 		return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
 	}
@@ -141,7 +141,7 @@ func (xl xlObjects) putObjectPartCommon(bucket string, object string, uploadID s
 	erasure := newErasure(onlineDisks, xlMeta.Erasure.Distribution)
 
 	partSuffix := fmt.Sprintf("object%d", partID)
-	tmpPartPath := path.Join(tmpMetaPrefix, bucket, object, uploadID, partSuffix)
+	tmpPartPath := path.Join(tmpMetaPrefix, uploadID, partSuffix)
 
 	// Initialize md5 writer.
 	md5Writer := md5.New()
@@ -173,6 +173,7 @@ func (xl xlObjects) putObjectPartCommon(bucket string, object string, uploadID s
 			return "", BadDigest{md5Hex, newMD5Hex}
 		}
 	}
+
 	partPath := path.Join(mpartMetaPrefix, bucket, object, uploadID, partSuffix)
 	err = xl.renameObject(minioMetaBucket, tmpPartPath, minioMetaBucket, partPath)
 	if err != nil {
@@ -184,7 +185,7 @@ func (xl xlObjects) putObjectPartCommon(bucket string, object string, uploadID s
 	xlMeta.AddObjectPart(partID, partSuffix, newMD5Hex, size)
 
 	uploadIDPath = path.Join(mpartMetaPrefix, bucket, object, uploadID)
-	tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	tempUploadIDPath := path.Join(tmpMetaPrefix, uploadID)
 	if err = xl.writeXLMetadata(minioMetaBucket, tempUploadIDPath, xlMeta); err != nil {
 		return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
 	}
@@ -372,7 +373,7 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 	// Save successfully calculated md5sum.
 	xlMeta.Meta["md5Sum"] = s3MD5
 	uploadIDPath = path.Join(mpartMetaPrefix, bucket, object, uploadID)
-	tempUploadIDPath := path.Join(tmpMetaPrefix, bucket, object, uploadID)
+	tempUploadIDPath := path.Join(tmpMetaPrefix, uploadID)
 	if err = xl.writeXLMetadata(minioMetaBucket, tempUploadIDPath, xlMeta); err != nil {
 		return "", toObjectErr(err, minioMetaBucket, tempUploadIDPath)
 	}
@@ -380,16 +381,13 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 	if rErr != nil {
 		return "", toObjectErr(rErr, minioMetaBucket, uploadIDPath)
 	}
-
 	// Hold write lock on the destination before rename
 	nsMutex.Lock(bucket, object)
 	defer nsMutex.Unlock(bucket, object)
 
-	// Delete if an object already exists.
+	// Rename if an object already exists to temporary location.
-	// FIXME: rename it to tmp file and delete only after
+	uniqueID := getUUID()
-	// the newly uploaded file is renamed from tmp location to
+	err = xl.renameObject(bucket, object, minioMetaBucket, path.Join(tmpMetaPrefix, uniqueID))
-	// the original location. Verify if the object is a multipart object.
-	err = xl.deleteObject(bucket, object)
 	if err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
@@ -407,10 +405,14 @@ func (xl xlObjects) CompleteMultipartUpload(bucket string, object string, upload
 		}
 	}
 
+	// Rename the multipart object to final location.
 	if err = xl.renameObject(minioMetaBucket, uploadIDPath, bucket, object); err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
 
+	// Delete the previously successfully renamed object.
+	xl.deleteObject(minioMetaBucket, path.Join(tmpMetaPrefix, uniqueID))
+
 	// Hold the lock so that two parallel complete-multipart-uploads do no
 	// leave a stale uploads.json behind.
 	nsMutex.Lock(minioMetaBucket, pathJoin(mpartMetaPrefix, bucket, object))

xl-v1-object.go

@@ -54,27 +54,22 @@ func (xl xlObjects) GetObject(bucket, object string, startOffset int64, length i
 	totalLeft := length
 	for ; partIndex < len(xlMeta.Parts); partIndex++ {
 		part := xlMeta.Parts[partIndex]
-		totalPartSize := part.Size
+		var buffer io.Reader
-		for totalPartSize > 0 {
+		buffer, err = erasure.ReadFile(bucket, pathJoin(object, part.Name), partOffset, part.Size)
-			var buffer io.Reader
+		if err != nil {
-			buffer, err = erasure.ReadFile(bucket, pathJoin(object, part.Name), partOffset, part.Size)
+			return err
-			if err != nil {
-				return err
-			}
-			if int64(buffer.(*bytes.Buffer).Len()) > totalLeft {
-				if _, err := io.CopyN(writer, buffer, totalLeft); err != nil {
-					return err
-				}
-				return nil
-			}
-			n, err := io.Copy(writer, buffer)
-			if err != nil {
-				return err
-			}
-			totalLeft -= n
-			totalPartSize -= n
-			partOffset += n
 		}
+		if int64(buffer.(*bytes.Buffer).Len()) > totalLeft {
+			if _, err := io.CopyN(writer, buffer, totalLeft); err != nil {
+				return err
+			}
+			return nil
+		}
+		n, err := io.Copy(writer, buffer)
+		if err != nil {
+			return err
+		}
+		totalLeft -= n
 		// Reset part offset to 0 to read rest of the parts from the beginning.
 		partOffset = 0
 	}
@@ -203,8 +198,9 @@ func (xl xlObjects) PutObject(bucket string, object string, size int64, data io.
 	nsMutex.Lock(bucket, object)
 	defer nsMutex.Unlock(bucket, object)
 
-	tempErasureObj := path.Join(tmpMetaPrefix, bucket, object, "object1")
+	uniqueID := getUUID()
-	tempObj := path.Join(tmpMetaPrefix, bucket, object)
+	tempErasureObj := path.Join(tmpMetaPrefix, uniqueID, "object1")
+	tempObj := path.Join(tmpMetaPrefix, uniqueID)
 
 	// Initialize xl meta.
 	xlMeta := newXLMetaV1(xl.dataBlocks, xl.parityBlocks)
@@ -281,13 +277,9 @@ func (xl xlObjects) PutObject(bucket string, object string, size int64, data io.
 		return "", toObjectErr(errFileAccessDenied, bucket, object)
 	}
 
-	// Delete if an object already exists.
+	// Rename if an object already exists to temporary location.
-	err = xl.deleteObject(bucket, object)
+	newUniqueID := getUUID()
-	if err != nil {
+	err = xl.renameObject(bucket, object, minioMetaBucket, path.Join(tmpMetaPrefix, newUniqueID))
-		return "", toObjectErr(err, bucket, object)
-	}
-
-	err = xl.renameObject(minioMetaBucket, tempObj, bucket, object)
 	if err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
@@ -298,13 +290,21 @@ func (xl xlObjects) PutObject(bucket string, object string, size int64, data io.
 	xlMeta.Stat.ModTime = modTime
 	xlMeta.Stat.Version = higherVersion
 	xlMeta.AddObjectPart(1, "object1", newMD5Hex, xlMeta.Stat.Size)
-	if err = xl.writeXLMetadata(minioMetaBucket, path.Join(tmpMetaPrefix, bucket, object), xlMeta); err != nil {
+
+	// Write `xl.json` metadata.
+	if err = xl.writeXLMetadata(minioMetaBucket, tempObj, xlMeta); err != nil {
 		return "", toObjectErr(err, bucket, object)
 	}
-	rErr := xl.renameXLMetadata(minioMetaBucket, path.Join(tmpMetaPrefix, bucket, object), bucket, object)
+
-	if rErr != nil {
+	// Rename the successfully written tempoary object to final location.
-		return "", toObjectErr(rErr, bucket, object)
+	err = xl.renameObject(minioMetaBucket, tempObj, bucket, object)
+	if err != nil {
+		return "", toObjectErr(err, bucket, object)
 	}
+
+	// Delete the temporary object.
+	xl.deleteObject(minioMetaBucket, path.Join(tmpMetaPrefix, newUniqueID))
+
 	// Return md5sum, successfully wrote object.
 	return newMD5Hex, nil
 }