multipart: Increase locked critical for CompleteMultipart.

pkg/fs/fs-bucket.go

@@ -30,15 +30,15 @@ import (
 
 /// Bucket Operations
 
-// DeleteBucket - delete bucket
+// DeleteBucket - delete a bucket.
 func (fs Filesystem) DeleteBucket(bucket string) *probe.Error {
-	// verify bucket path legal
+	// Verify bucket is valid.
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 	bucket = fs.denormalizeBucket(bucket)
 	bucketDir := filepath.Join(fs.path, bucket)
-	// check bucket exists
+	// Check if bucket exists.
 	if _, e := os.Stat(bucketDir); e != nil {
 		if os.IsNotExist(e) {
 			return probe.NewError(BucketNotFound{Bucket: bucket})
@@ -57,12 +57,15 @@ func (fs Filesystem) DeleteBucket(bucket string) *probe.Error {
 		}
 		return probe.NewError(e)
 	}
+
+	// Critical region hold write lock.
 	fs.rwLock.Lock()
 	delete(fs.buckets.Metadata, bucket)
-	fs.rwLock.Unlock()
 	if err := saveBucketsMetadata(*fs.buckets); err != nil {
+		fs.rwLock.Unlock()
 		return err.Trace(bucket)
 	}
+	fs.rwLock.Unlock()
 	return nil
 }
 
@@ -73,22 +76,21 @@ func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
 		return []BucketMetadata{}, probe.NewError(err)
 	}
 	if err == io.EOF {
-		// This message is printed if there are more than 1000 buckets.
+		// This message is printed if there are more than 1000 buckets
+		// and we saw io.EOF.
 		fmt.Printf("More buckets found, truncating the bucket list to %d entries only.", fs.maxBuckets)
 	}
 	var metadataList []BucketMetadata
 	for _, file := range files {
 		if !file.IsDir() {
-			// if files found ignore them
+			// If not directory, ignore all file types.
 			continue
 		}
+		// If directories are found with odd names, skip them.
 		dirName := strings.ToLower(file.Name())
-		if file.IsDir() {
+		if file.IsDir() && !IsValidBucketName(dirName) {
-			// If directories found with odd names, skip them.
-			if !IsValidBucketName(dirName) {
 			continue
 		}
-		}
 		metadata := BucketMetadata{
 			Name:    dirName,
 			Created: file.ModTime(),
@@ -127,19 +129,18 @@ func (fs Filesystem) MakeBucket(bucket, acl string) *probe.Error {
 		return probe.NewError(RootPathFull{Path: fs.path})
 	}
 
-	// Verify if bucket path legal.
+	// Verify if bucket is valid.
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
-	// Verify if bucket acl is legal.
+	// Verify if bucket acl is valid.
 	if !IsValidBucketACL(acl) {
 		return probe.NewError(InvalidACL{ACL: acl})
 	}
 
-	bucket = fs.denormalizeBucket(bucket)
-
 	// Get bucket path.
+	bucket = fs.denormalizeBucket(bucket)
 	bucketDir := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketDir); e == nil {
 		return probe.NewError(BucketExists{Bucket: bucket})
@@ -150,7 +151,6 @@ func (fs Filesystem) MakeBucket(bucket, acl string) *probe.Error {
 		return probe.NewError(err)
 	}
 
-	bucketMetadata := &BucketMetadata{}
 	fi, e := os.Stat(bucketDir)
 	// Check if bucket exists.
 	if e != nil {
@@ -162,15 +162,21 @@ func (fs Filesystem) MakeBucket(bucket, acl string) *probe.Error {
 	if strings.TrimSpace(acl) == "" {
 		acl = "private"
 	}
+
+	// Get a new bucket name metadata.
+	bucketMetadata := &BucketMetadata{}
 	bucketMetadata.Name = fi.Name()
 	bucketMetadata.Created = fi.ModTime()
 	bucketMetadata.ACL = BucketACL(acl)
+
+	// Critical region hold a write lock.
 	fs.rwLock.Lock()
 	fs.buckets.Metadata[bucket] = bucketMetadata
-	fs.rwLock.Unlock()
 	if err := saveBucketsMetadata(*fs.buckets); err != nil {
+		fs.rwLock.Unlock()
 		return err.Trace(bucket)
 	}
+	fs.rwLock.Unlock()
 	return nil
 }
 
@@ -212,6 +218,7 @@ func (fs Filesystem) GetBucketMetadata(bucket string) (BucketMetadata, *probe.Er
 	fs.rwLock.RLock()
 	bucketMetadata, ok := fs.buckets.Metadata[bucket]
 	fs.rwLock.RUnlock()
+	// If metadata value is not found, get it from disk.
 	if !ok {
 		bucketMetadata = &BucketMetadata{}
 		bucketMetadata.Name = fi.Name()
@@ -245,6 +252,8 @@ func (fs Filesystem) SetBucketMetadata(bucket string, metadata map[string]string
 		}
 		return probe.NewError(e)
 	}
+
+	// Critical region handle read lock.
 	fs.rwLock.RLock()
 	bucketMetadata, ok := fs.buckets.Metadata[bucket]
 	fs.rwLock.RUnlock()
@@ -254,11 +263,14 @@ func (fs Filesystem) SetBucketMetadata(bucket string, metadata map[string]string
 		bucketMetadata.Created = fi.ModTime()
 	}
 	bucketMetadata.ACL = BucketACL(acl)
+
+	// Critical region handle write lock.
 	fs.rwLock.Lock()
 	fs.buckets.Metadata[bucket] = bucketMetadata
-	fs.rwLock.Unlock()
 	if err := saveBucketsMetadata(*fs.buckets); err != nil {
+		fs.rwLock.Unlock()
 		return err.Trace(bucket)
 	}
+	fs.rwLock.Unlock()
 	return nil
 }

pkg/fs/fs-multipart.go

@@ -236,6 +236,7 @@ func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.E
 	uploadIDSum := sha512.Sum512(id)
 	uploadID := base64.URLEncoding.EncodeToString(uploadIDSum[:])[:47]
 
+	// Critical region requiring write lock.
 	fs.rwLock.Lock()
 	// Initialize multipart session.
 	mpartSession := &MultipartSession{}
@@ -364,6 +365,7 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	partMetadata.Size = fi.Size()
 	partMetadata.LastModified = fi.ModTime()
 
+	// Critical region requiring read lock.
 	fs.rwLock.RLock()
 	deserializedMultipartSession, ok := fs.multiparts.ActiveSession[uploadID]
 	fs.rwLock.RUnlock()
@@ -382,6 +384,7 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	// Sort by part number before saving.
 	sort.Sort(partNumber(deserializedMultipartSession.Parts))
 
+	// Critical region requiring write lock.
 	fs.rwLock.Lock()
 	fs.multiparts.ActiveSession[uploadID] = deserializedMultipartSession
 	if err := saveMultipartsSession(*fs.multiparts); err != nil {
@@ -390,6 +393,7 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	}
 	fs.rwLock.Unlock()
 
+	// Return etag.
 	return partMetadata.ETag, nil
 }
 
@@ -459,6 +463,7 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 	// Save parts for verification.
 	parts := completeMultipartUpload.Part
 
+	// Critical region requiring read lock.
 	fs.rwLock.RLock()
 	savedParts := fs.multiparts.ActiveSession[uploadID].Parts
 	fs.rwLock.RUnlock()
@@ -468,6 +473,7 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 		return ObjectMetadata{}, probe.NewError(InvalidPart{})
 	}
 
+	// Parts successfully validated, save all the parts.
 	partPathPrefix := objectPath + uploadID
 	if err := saveParts(partPathPrefix, objectWriter, parts); err != nil {
 		file.CloseAndPurge()
@@ -476,6 +482,7 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 	// Successfully saved, remove all parts.
 	removeParts(partPathPrefix, savedParts)
 
+	// Critical region requiring write lock.
 	fs.rwLock.Lock()
 	delete(fs.multiparts.ActiveSession, uploadID)
 	if err := saveMultipartsSession(*fs.multiparts); err != nil {
@@ -483,10 +490,10 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 		file.CloseAndPurge()
 		return ObjectMetadata{}, err.Trace(partPathPrefix)
 	}
-	fs.rwLock.Unlock()
-
 	file.Close()
+	fs.rwLock.Unlock()
 
+	// Send stat again to get object metadata.
 	st, e := os.Stat(objectPath)
 	if e != nil {
 		return ObjectMetadata{}, probe.NewError(e)
@@ -550,6 +557,7 @@ func (fs Filesystem) ListObjectParts(bucket, object string, resources ObjectReso
 		return ObjectResourcesMetadata{}, probe.NewError(e)
 	}
 
+	// Critical region requiring read lock.
 	fs.rwLock.RLock()
 	deserializedMultipartSession, ok := fs.multiparts.ActiveSession[uploadID]
 	fs.rwLock.RUnlock()
@@ -600,14 +608,18 @@ func (fs Filesystem) AbortMultipartUpload(bucket, object, uploadID string) *prob
 
 	objectPath := filepath.Join(bucketPath, object)
 	partPathPrefix := objectPath + uploadID
+
+	// Critical region requiring read lock.
 	fs.rwLock.RLock()
 	savedParts := fs.multiparts.ActiveSession[uploadID].Parts
 	fs.rwLock.RUnlock()
 
+	// Remove all parts.
 	if err := removeParts(partPathPrefix, savedParts); err != nil {
 		return err.Trace(partPathPrefix)
 	}
 
+	// Critical region requiring write lock.
 	fs.rwLock.Lock()
 	delete(fs.multiparts.ActiveSession, uploadID)
 	if err := saveMultipartsSession(*fs.multiparts); err != nil {

pkg/fs/fs-object.go

@@ -40,6 +40,7 @@ import (
 
 // GetObject - GET object
 func (fs Filesystem) GetObject(w io.Writer, bucket, object string, start, length int64) (int64, *probe.Error) {
+	// Critical region requiring read lock.
 	fs.rwLock.RLock()
 	defer fs.rwLock.RUnlock()
 
@@ -111,7 +112,7 @@ func (fs Filesystem) GetObjectMetadata(bucket, object string) (ObjectMetadata, *
 		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: bucket})
 	}
 
-	// normalize buckets.
+	// Normalize buckets.
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
@@ -175,7 +176,10 @@ func getMetadata(rootPath, bucket, object string) (ObjectMetadata, *probe.Error)
 
 // isMD5SumEqual - returns error if md5sum mismatches, success its `nil`
 func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) bool {
+	// Verify the md5sum.
 	if strings.TrimSpace(expectedMD5Sum) != "" && strings.TrimSpace(actualMD5Sum) != "" {
+		// Decode md5sum to bytes from their hexadecimal
+		// representations.
 		expectedMD5SumBytes, err := hex.DecodeString(expectedMD5Sum)
 		if err != nil {
 			return false
@@ -184,6 +188,7 @@ func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) bool {
 		if err != nil {
 			return false
 		}
+		// Verify md5sum bytes are equal after successful decoding.
 		if !bytes.Equal(expectedMD5SumBytes, actualMD5SumBytes) {
 			return false
 		}
@@ -219,6 +224,7 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 		}
 		return ObjectMetadata{}, probe.NewError(e)
 	}
+
 	// Verify object path legal.
 	if !IsValidObjectName(object) {
 		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
@@ -252,23 +258,24 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 		}
 	}
 
-	h := md5.New()
+	// Instantiate checksum hashers and create a multiwriter.
-	sh := sha256.New()
+	md5Hasher := md5.New()
-	mw := io.MultiWriter(file, h, sh)
+	sha256Hasher := sha256.New()
+	objectWriter := io.MultiWriter(file, md5Hasher, sha256Hasher)
 
 	if size > 0 {
-		if _, e = io.CopyN(mw, data, size); e != nil {
+		if _, e = io.CopyN(objectWriter, data, size); e != nil {
 			file.CloseAndPurge()
 			return ObjectMetadata{}, probe.NewError(e)
 		}
 	} else {
-		if _, e = io.Copy(mw, data); e != nil {
+		if _, e = io.Copy(objectWriter, data); e != nil {
 			file.CloseAndPurge()
 			return ObjectMetadata{}, probe.NewError(e)
 		}
 	}
 
-	md5Sum := hex.EncodeToString(h.Sum(nil))
+	md5Sum := hex.EncodeToString(md5Hasher.Sum(nil))
 	// Verify if the written object is equal to what is expected, only
 	// if it is requested as such.
 	if strings.TrimSpace(expectedMD5Sum) != "" {
@@ -277,7 +284,7 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 			return ObjectMetadata{}, probe.NewError(BadDigest{MD5: expectedMD5Sum, Bucket: bucket, Object: object})
 		}
 	}
-	sha256Sum := hex.EncodeToString(sh.Sum(nil))
+	sha256Sum := hex.EncodeToString(sha256Hasher.Sum(nil))
 	if signature != nil {
 		ok, err := signature.DoesSignatureMatch(sha256Sum)
 		if err != nil {
@@ -291,6 +298,7 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 	}
 	file.Close()
 
+	// Set stat again to get the latest metadata.
 	st, e := os.Stat(objectPath)
 	if e != nil {
 		return ObjectMetadata{}, probe.NewError(e)
@@ -318,6 +326,7 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 	if basePath == deletePath {
 		return nil
 	}
+	// Verify if the path exists.
 	pathSt, e := os.Stat(deletePath)
 	if e != nil {
 		if os.IsNotExist(e) {
@@ -326,6 +335,7 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 		return probe.NewError(e)
 	}
 	if pathSt.IsDir() {
+		// Verify if directory is empty.
 		empty, e := ioutils.IsDirEmpty(deletePath)
 		if e != nil {
 			return probe.NewError(e)
@@ -334,25 +344,27 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 			return nil
 		}
 	}
+	// Attempt to remove path.
 	if e := os.Remove(deletePath); e != nil {
 		return probe.NewError(e)
 	}
+	// Recursively go down the next path and delete again.
 	if err := deleteObjectPath(basePath, filepath.Dir(deletePath), bucket, object); err != nil {
 		return err.Trace(basePath, deletePath, bucket, object)
 	}
 	return nil
 }
 
-// DeleteObject - delete and object
+// DeleteObject - delete object.
 func (fs Filesystem) DeleteObject(bucket, object string) *probe.Error {
-	// check bucket name valid
+	// Check bucket name valid
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
-	// check bucket exists
+	// Check bucket exists
 	if _, e := os.Stat(bucketPath); e != nil {
 		if os.IsNotExist(e) {
 			return probe.NewError(BucketNotFound{Bucket: bucket})
@@ -360,19 +372,22 @@ func (fs Filesystem) DeleteObject(bucket, object string) *probe.Error {
 		return probe.NewError(e)
 	}
 
-	// verify object path legal
+	// Verify object path legal
 	if !IsValidObjectName(object) {
 		return probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
-	// Do not use filepath.Join() since filepath.Join strips off any object names with '/', use them as is
+	// Do not use filepath.Join() since filepath.Join strips off any
-	// in a static manner so that we can send a proper 'ObjectNotFound' reply back upon os.Stat()
+	// object names with '/', use them as is in a static manner so
+	// that we can send a proper 'ObjectNotFound' reply back upon
+	// os.Stat().
 	var objectPath string
 	if runtime.GOOS == "windows" {
 		objectPath = fs.path + string(os.PathSeparator) + bucket + string(os.PathSeparator) + object
 	} else {
 		objectPath = fs.path + string(os.PathSeparator) + bucket + string(os.PathSeparator) + object
 	}
+	// Delete object path if its empty.
 	err := deleteObjectPath(bucketPath, objectPath, bucket, object)
 	if err != nil {
 		if os.IsNotExist(err.ToGoError()) {