Merge pull request #1090 from harshavardhana/multipart

fs: Add granular locking.

pkg/fs/acl.go

@@ -18,8 +18,8 @@ package fs
 
 // IsPrivateBucket - is private bucket
 func (fs Filesystem) IsPrivateBucket(bucket string) bool {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 	bucketMetadata, ok := fs.buckets.Metadata[bucket]
 	if !ok {
 		return true
@@ -29,8 +29,8 @@ func (fs Filesystem) IsPrivateBucket(bucket string) bool {
 
 // IsPublicBucket - is public bucket
 func (fs Filesystem) IsPublicBucket(bucket string) bool {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 	bucketMetadata, ok := fs.buckets.Metadata[bucket]
 	if !ok {
 		return true
@@ -40,8 +40,8 @@ func (fs Filesystem) IsPublicBucket(bucket string) bool {
 
 // IsReadOnlyBucket - is read only bucket
 func (fs Filesystem) IsReadOnlyBucket(bucket string) bool {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 	bucketMetadata, ok := fs.buckets.Metadata[bucket]
 	if !ok {
 		return true

pkg/fs/fs-bucket-listobjects.go

@@ -271,16 +271,17 @@ func (fs *Filesystem) listObjectsService() *probe.Error {
 // ListObjects - lists all objects for a given prefix, returns upto
 // maxKeys number of objects per call.
 func (fs Filesystem) ListObjects(bucket, prefix, marker, delimiter string, maxKeys int) (ListObjectsResult, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
 
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return ListObjectsResult{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
 	bucket = fs.denormalizeBucket(bucket)
 	rootPrefix := filepath.Join(fs.path, bucket)
-	// check bucket exists
+	// Check bucket exists.
 	if _, e := os.Stat(rootPrefix); e != nil {
 		if os.IsNotExist(e) {
 			return ListObjectsResult{}, probe.NewError(BucketNotFound{Bucket: bucket})

pkg/fs/fs-bucket.go

@@ -32,8 +32,8 @@ import (
 
 // DeleteBucket - delete bucket
 func (fs Filesystem) DeleteBucket(bucket string) *probe.Error {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 	// verify bucket path legal
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
@@ -66,29 +66,18 @@ func (fs Filesystem) DeleteBucket(bucket string) *probe.Error {
 	return nil
 }
 
-func removeDuplicateBuckets(elements []BucketMetadata) (result []BucketMetadata) {
-	// Use map to record duplicates as we find them.
-	duplicates := make(map[string]struct{})
-	for _, element := range elements {
-		if _, ok := duplicates[element.Name]; !ok {
-			duplicates[element.Name] = struct{}{}
-			result = append(result, element)
-		}
-	}
-	return result
-}
-
-// ListBuckets - Get service
+// ListBuckets - Get service.
 func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
 
 	files, err := ioutils.ReadDirN(fs.path, fs.maxBuckets)
 	if err != nil && err != io.EOF {
 		return []BucketMetadata{}, probe.NewError(err)
 	}
 	if err == io.EOF {
-		fmt.Printf("Truncating the bucket list to %d entries only.", fs.maxBuckets)
+		// This message is printed if there are more than 1000 buckets.
+		fmt.Printf("More buckets found, truncating the bucket list to %d entries only.", fs.maxBuckets)
 	}
 	var metadataList []BucketMetadata
 	for _, file := range files {
@@ -98,7 +87,7 @@ func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
 		}
 		dirName := strings.ToLower(file.Name())
 		if file.IsDir() {
-			// if directories found with odd names, skip them too
+			// If directories found with odd names, skip them.
 			if !IsValidBucketName(dirName) {
 				continue
 			}
@@ -109,50 +98,67 @@ func (fs Filesystem) ListBuckets() ([]BucketMetadata, *probe.Error) {
 		}
 		metadataList = append(metadataList, metadata)
 	}
+	// Remove duplicated entries.
 	metadataList = removeDuplicateBuckets(metadataList)
 	return metadataList, nil
 }
 
-// MakeBucket - PUT Bucket
+// removeDuplicateBuckets - remove duplicate buckets.
+func removeDuplicateBuckets(elements []BucketMetadata) (result []BucketMetadata) {
+	// Use map to record duplicates as we find them.
+	duplicates := make(map[string]struct{})
+	for _, element := range elements {
+		if _, ok := duplicates[element.Name]; !ok {
+			duplicates[element.Name] = struct{}{}
+			result = append(result, element)
+		}
+	}
+	return result
+}
+
+// MakeBucket - PUT Bucket.
 func (fs Filesystem) MakeBucket(bucket, acl string) *probe.Error {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
 	di, err := disk.GetInfo(fs.path)
 	if err != nil {
 		return probe.NewError(err)
 	}
 
-	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
+	// Remove 5% from total space for cumulative disk space used for
+	// journalling, inodes etc.
 	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
 	if int64(availableDiskSpace) <= fs.minFreeDisk {
 		return probe.NewError(RootPathFull{Path: fs.path})
 	}
 
-	// verify bucket path legal
+	// Verify if bucket path legal.
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
+	// Verify if bucket acl is legal.
 	if !IsValidBucketACL(acl) {
 		return probe.NewError(InvalidACL{ACL: acl})
 	}
 
 	bucket = fs.denormalizeBucket(bucket)
-	// get bucket path
+
+	// Get bucket path.
 	bucketDir := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketDir); e == nil {
 		return probe.NewError(BucketExists{Bucket: bucket})
 	}
 
-	// make bucket
+	// Make bucket.
 	if e := os.Mkdir(bucketDir, 0700); e != nil {
 		return probe.NewError(err)
 	}
 
 	bucketMetadata := &BucketMetadata{}
 	fi, e := os.Stat(bucketDir)
-	// check if bucket exists
+	// Check if bucket exists.
 	if e != nil {
 		if os.IsNotExist(e) {
 			return probe.NewError(BucketNotFound{Bucket: bucket})
@@ -172,12 +178,17 @@ func (fs Filesystem) MakeBucket(bucket, acl string) *probe.Error {
 	return nil
 }
 
+// denormalizeBucket - will convert incoming bucket names to
+// corresponding valid bucketnames on the backend in a platform
+// compatible way for all operating systems.
 func (fs Filesystem) denormalizeBucket(bucket string) string {
-	buckets, err := ioutils.ReadDirNamesN(fs.path, fs.maxBuckets)
-	if err != nil {
+	buckets, e := ioutils.ReadDirNamesN(fs.path, fs.maxBuckets)
+	if e != nil {
 		return bucket
 	}
 	for _, b := range buckets {
+		// Verify if lowercase version of the bucket is equal to the
+		// incoming bucket, then use the proper name.
 		if strings.ToLower(b) == bucket {
 			return b
 		}
@@ -185,21 +196,20 @@ func (fs Filesystem) denormalizeBucket(bucket string) string {
 	return bucket
 }
 
-// GetBucketMetadata - get bucket metadata
+// GetBucketMetadata - get bucket metadata.
 func (fs Filesystem) GetBucketMetadata(bucket string) (BucketMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
 	if !IsValidBucketName(bucket) {
 		return BucketMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
 	bucket = fs.denormalizeBucket(bucket)
-
-	// get bucket path
+	// Get bucket path.
 	bucketDir := filepath.Join(fs.path, bucket)
 	fi, e := os.Stat(bucketDir)
 	if e != nil {
-		// check if bucket exists
+		// Check if bucket exists.
 		if os.IsNotExist(e) {
 			return BucketMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -215,13 +225,15 @@ func (fs Filesystem) GetBucketMetadata(bucket string) (BucketMetadata, *probe.Er
 	return *bucketMetadata, nil
 }
 
-// SetBucketMetadata - set bucket metadata
+// SetBucketMetadata - set bucket metadata.
 func (fs Filesystem) SetBucketMetadata(bucket string, metadata map[string]string) *probe.Error {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
+	// Save the acl.
 	acl := metadata["acl"]
 	if !IsValidBucketACL(acl) {
 		return probe.NewError(InvalidACL{ACL: acl})
@@ -233,7 +245,7 @@ func (fs Filesystem) SetBucketMetadata(bucket string, metadata map[string]string
 	bucketDir := filepath.Join(fs.path, bucket)
 	fi, e := os.Stat(bucketDir)
 	if e != nil {
-		// check if bucket exists
+		// Check if bucket exists.
 		if os.IsNotExist(e) {
 			return probe.NewError(BucketNotFound{Bucket: bucket})
 		}

pkg/fs/fs-multipart.go

@@ -42,6 +42,7 @@ import (
 	"github.com/minio/minio/pkg/disk"
 )
 
+// isValidUploadID - is upload id.
 func (fs Filesystem) isValidUploadID(object, uploadID string) bool {
 	s, ok := fs.multiparts.ActiveSession[object]
 	if !ok {
@@ -55,15 +56,17 @@ func (fs Filesystem) isValidUploadID(object, uploadID string) bool {
 
 // ListMultipartUploads - list incomplete multipart sessions for a given BucketMultipartResourcesMetadata
 func (fs Filesystem) ListMultipartUploads(bucket string, resources BucketMultipartResourcesMetadata) (BucketMultipartResourcesMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
+
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return BucketMultipartResourcesMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(e) {
 			return BucketMultipartResourcesMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -80,7 +83,7 @@ func (fs Filesystem) ListMultipartUploads(bucket string, resources BucketMultipa
 				resources.IsTruncated = true
 				return resources, nil
 			}
-			// uploadIDMarker is ignored if KeyMarker is empty
+			// UploadIDMarker is ignored if KeyMarker is empty.
 			switch {
 			case resources.KeyMarker != "" && resources.UploadIDMarker == "":
 				if object > resources.KeyMarker {
@@ -114,6 +117,7 @@ func (fs Filesystem) ListMultipartUploads(bucket string, resources BucketMultipa
 	return resources, nil
 }
 
+// concatenate parts.
 func (fs Filesystem) concatParts(parts *CompleteMultipartUpload, objectPath string, mw io.Writer) *probe.Error {
 	for _, part := range parts.Part {
 		partFile, e := os.OpenFile(objectPath+fmt.Sprintf("$%d-$multiparts", part.PartNumber), os.O_RDONLY, 0600)
@@ -123,15 +127,13 @@ func (fs Filesystem) concatParts(parts *CompleteMultipartUpload, objectPath stri
 		}
 
 		recvMD5 := part.ETag
-		// complete multipart request header md5sum per part is hex encoded
-		// trim it and decode if possible.
-		_, e = hex.DecodeString(strings.Trim(recvMD5, "\""))
-		if e != nil {
+		// Complete multipart request header md5sum per part is hex
+		// encoded trim it and decode if possible.
+		if _, e = hex.DecodeString(strings.Trim(recvMD5, "\"")); e != nil {
 			return probe.NewError(InvalidDigest{Md5: recvMD5})
 		}
 
-		_, e = io.Copy(mw, partFile)
-		if e != nil {
+		if _, e = io.Copy(mw, partFile); e != nil {
 			return probe.NewError(e)
 		}
 	}
@@ -140,20 +142,22 @@ func (fs Filesystem) concatParts(parts *CompleteMultipartUpload, objectPath stri
 
 // NewMultipartUpload - initiate a new multipart session
 func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
 	di, e := disk.GetInfo(fs.path)
 	if e != nil {
 		return "", probe.NewError(e)
 	}
 
-	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
+	// Remove 5% from total space for cumulative disk space used for
+	// journalling, inodes etc.
 	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
 	if int64(availableDiskSpace) <= fs.minFreeDisk {
 		return "", probe.NewError(RootPathFull{Path: fs.path})
 	}
 
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
@@ -164,7 +168,7 @@ func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.E
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e = os.Stat(bucketPath); e != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(e) {
 			return "", probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -183,6 +187,7 @@ func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.E
 		}
 	}
 
+	// Generate new upload id.
 	id := []byte(strconv.FormatInt(rand.Int63(), 10) + bucket + object + time.Now().String())
 	uploadIDSum := sha512.Sum512(id)
 	uploadID := base64.URLEncoding.EncodeToString(uploadIDSum[:])[:47]
@@ -193,6 +198,7 @@ func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.E
 	}
 	defer multiPartfile.Close()
 
+	// Initialize multipart session.
 	mpartSession := &MultipartSession{}
 	mpartSession.TotalParts = 0
 	mpartSession.UploadID = uploadID
@@ -211,7 +217,7 @@ func (fs Filesystem) NewMultipartUpload(bucket, object string) (string, *probe.E
 	return uploadID, nil
 }
 
-// partNumber is a sortable interface for Part slice
+// partNumber is a sortable interface for Part slice.
 type partNumber []*PartMetadata
 
 func (a partNumber) Len() int           { return len(a) }
@@ -220,33 +226,37 @@ func (a partNumber) Less(i, j int) bool { return a[i].PartNumber < a[j].PartNumb
 
 // CreateObjectPart - create a part in a multipart session
 func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum string, partID int, size int64, data io.Reader, signature *Signature) (string, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
 	di, err := disk.GetInfo(fs.path)
 	if err != nil {
 		return "", probe.NewError(err)
 	}
 
-	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
+	// Remove 5% from total space for cumulative disk space used for
+	// journalling, inodes etc.
 	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
 	if int64(availableDiskSpace) <= fs.minFreeDisk {
 		return "", probe.NewError(RootPathFull{Path: fs.path})
 	}
 
+	// Part id cannot be negative.
 	if partID <= 0 {
 		return "", probe.NewError(errors.New("invalid part id, cannot be zero or less than zero"))
 	}
-	// check bucket name valid
+
+	// Check bucket name valid.
 	if !IsValidBucketName(bucket) {
 		return "", probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
-	// verify object path legal
+	// Verify object path legal.
 	if !IsValidObjectName(object) {
 		return "", probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
+	// Verify upload is valid for the incoming object.
 	if !fs.isValidUploadID(object, uploadID) {
 		return "", probe.NewError(InvalidUploadID{UploadID: uploadID})
 	}
@@ -255,7 +265,7 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 		var expectedMD5SumBytes []byte
 		expectedMD5SumBytes, err = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
 		if err != nil {
-			// pro-actively close the connection
+			// Pro-actively close the connection
 			return "", probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
 		}
 		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
@@ -264,7 +274,7 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, err = os.Stat(bucketPath); err != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(err) {
 			return "", probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -285,7 +295,8 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 		return "", probe.NewError(e)
 	}
 	md5sum := hex.EncodeToString(h.Sum(nil))
-	// Verify if the written object is equal to what is expected, only if it is requested as such
+	// Verify if the written object is equal to what is expected, only
+	// if it is requested as such.
 	if strings.TrimSpace(expectedMD5Sum) != "" {
 		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5sum) {
 			partFile.CloseAndPurge()
@@ -340,19 +351,20 @@ func (fs Filesystem) CreateObjectPart(bucket, object, uploadID, expectedMD5Sum s
 
 // CompleteMultipartUpload - complete a multipart upload and persist the data
 func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
-	// check bucket name valid
+	// Check bucket name is valid.
 	if !IsValidBucketName(bucket) {
 		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
-	// verify object path legal
+	// Verify object path is legal.
 	if !IsValidObjectName(object) {
 		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
+	// Verify if valid upload for incoming object.
 	if !fs.isValidUploadID(object, uploadID) {
 		return ObjectMetadata{}, probe.NewError(InvalidUploadID{UploadID: uploadID})
 	}
@@ -360,7 +372,7 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(e) {
 			return ObjectMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -446,19 +458,20 @@ func (fs Filesystem) CompleteMultipartUpload(bucket, object, uploadID string, da
 
 // ListObjectParts - list parts from incomplete multipart session for a given ObjectResourcesMetadata
 func (fs Filesystem) ListObjectParts(bucket, object string, resources ObjectResourcesMetadata) (ObjectResourcesMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
-	// check bucket name valid
+	// Check bucket name is valid.
 	if !IsValidBucketName(bucket) {
 		return ObjectResourcesMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
-	// verify object path legal
+	// Verify object path legal.
 	if !IsValidObjectName(object) {
 		return ObjectResourcesMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
+	// Verify if upload id is valid for incoming object.
 	if !fs.isValidUploadID(object, resources.UploadID) {
 		return ObjectResourcesMetadata{}, probe.NewError(InvalidUploadID{UploadID: resources.UploadID})
 	}
@@ -477,7 +490,7 @@ func (fs Filesystem) ListObjectParts(bucket, object string, resources ObjectReso
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(e) {
 			return ObjectResourcesMetadata{}, probe.NewError(BucketNotFound{Bucket: bucket})
 		}
@@ -514,15 +527,15 @@ func (fs Filesystem) ListObjectParts(bucket, object string, resources ObjectReso
 
 // AbortMultipartUpload - abort an incomplete multipart session
 func (fs Filesystem) AbortMultipartUpload(bucket, object, uploadID string) *probe.Error {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
-	// check bucket name valid
+	// Check bucket name valid.
 	if !IsValidBucketName(bucket) {
 		return probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
 
-	// verify object path legal
+	// Verify object path legal.
 	if !IsValidObjectName(object) {
 		return probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
@@ -534,7 +547,7 @@ func (fs Filesystem) AbortMultipartUpload(bucket, object, uploadID string) *prob
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
-		// check bucket exists
+		// Check bucket exists.
 		if os.IsNotExist(e) {
 			return probe.NewError(BucketNotFound{Bucket: bucket})
 		}

pkg/fs/fs-object.go

@@ -40,19 +40,18 @@ import (
 
 // GetObject - GET object
 func (fs Filesystem) GetObject(w io.Writer, bucket, object string, start, length int64) (int64, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
 
-	// validate bucket
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return 0, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
-
-	// validate object
 	if !IsValidObjectName(object) {
 		return 0, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
+	// normalize buckets.
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
@@ -101,11 +100,12 @@ func (fs Filesystem) GetObject(w io.Writer, bucket, object string, start, length
 	return count, nil
 }
 
-// GetObjectMetadata - HEAD object
+// GetObjectMetadata - get object metadata.
 func (fs Filesystem) GetObjectMetadata(bucket, object string) (ObjectMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.RLock()
+	defer fs.rwLock.RUnlock()
 
+	// Input validation.
 	if !IsValidBucketName(bucket) {
 		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
@@ -114,6 +114,7 @@ func (fs Filesystem) GetObjectMetadata(bucket, object string) (ObjectMetadata, *
 		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: bucket})
 	}
 
+	// normalize buckets.
 	bucket = fs.denormalizeBucket(bucket)
 	bucketPath := filepath.Join(fs.path, bucket)
 	if _, e := os.Stat(bucketPath); e != nil {
@@ -133,9 +134,12 @@ func (fs Filesystem) GetObjectMetadata(bucket, object string) (ObjectMetadata, *
 	return metadata, nil
 }
 
+// getMetadata - get object metadata.
 func getMetadata(rootPath, bucket, object string) (ObjectMetadata, *probe.Error) {
-	// Do not use filepath.Join() since filepath.Join strips off any object names with '/', use them as is
-	// in a static manner so that we can send a proper 'ObjectNotFound' reply back upon os.Stat()
+	// Do not use filepath.Join() since filepath.Join strips off any
+	// 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
 	// For windows use its special os.PathSeparator == "\\"
 	if runtime.GOOS == "windows" {
@@ -187,23 +191,24 @@ func isMD5SumEqual(expectedMD5Sum, actualMD5Sum string) bool {
 	return false
 }
 
-// CreateObject - PUT object
+// CreateObject - create an object.
 func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size int64, data io.Reader, signature *Signature) (ObjectMetadata, *probe.Error) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
 	di, e := disk.GetInfo(fs.path)
 	if e != nil {
 		return ObjectMetadata{}, probe.NewError(e)
 	}
 
-	// Remove 5% from total space for cumulative disk space used for journalling, inodes etc.
+	// Remove 5% from total space for cumulative disk space used for
+	// journalling, inodes etc.
 	availableDiskSpace := (float64(di.Free) / (float64(di.Total) - (0.05 * float64(di.Total)))) * 100
 	if int64(availableDiskSpace) <= fs.minFreeDisk {
 		return ObjectMetadata{}, probe.NewError(RootPathFull{Path: fs.path})
 	}
 
-	// check bucket name valid
+	// Check bucket name valid.
 	if !IsValidBucketName(bucket) {
 		return ObjectMetadata{}, probe.NewError(BucketNameInvalid{Bucket: bucket})
 	}
@@ -216,24 +221,24 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 		}
 		return ObjectMetadata{}, probe.NewError(e)
 	}
-	// verify object path legal
+	// Verify object path legal.
 	if !IsValidObjectName(object) {
 		return ObjectMetadata{}, probe.NewError(ObjectNameInvalid{Bucket: bucket, Object: object})
 	}
 
-	// get object path
+	// Get object path.
 	objectPath := filepath.Join(bucketPath, object)
 	if strings.TrimSpace(expectedMD5Sum) != "" {
 		var expectedMD5SumBytes []byte
 		expectedMD5SumBytes, e = base64.StdEncoding.DecodeString(strings.TrimSpace(expectedMD5Sum))
 		if e != nil {
-			// pro-actively close the connection
+			// Pro-actively close the connection.
 			return ObjectMetadata{}, probe.NewError(InvalidDigest{Md5: expectedMD5Sum})
 		}
 		expectedMD5Sum = hex.EncodeToString(expectedMD5SumBytes)
 	}
 
-	// write object
+	// Write object.
 	file, e := atomic.FileCreateWithPrefix(objectPath, "")
 	if e != nil {
 		switch e := e.(type) {
@@ -266,7 +271,8 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 	}
 
 	md5Sum := hex.EncodeToString(h.Sum(nil))
-	// Verify if the written object is equal to what is expected, only if it is requested as such
+	// Verify if the written object is equal to what is expected, only
+	// if it is requested as such.
 	if strings.TrimSpace(expectedMD5Sum) != "" {
 		if !isMD5SumEqual(strings.TrimSpace(expectedMD5Sum), md5Sum) {
 			file.CloseAndPurge()
@@ -306,18 +312,19 @@ func (fs Filesystem) CreateObject(bucket, object, expectedMD5Sum string, size in
 	return newObject, nil
 }
 
+// deleteObjectPath - delete object path if its empty.
 func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error {
 	if basePath == deletePath {
 		return nil
 	}
-	fi, e := os.Stat(deletePath)
+	pathSt, e := os.Stat(deletePath)
 	if e != nil {
 		if os.IsNotExist(e) {
 			return probe.NewError(ObjectNotFound{Bucket: bucket, Object: object})
 		}
 		return probe.NewError(e)
 	}
-	if fi.IsDir() {
+	if pathSt.IsDir() {
 		empty, e := ioutils.IsDirEmpty(deletePath)
 		if e != nil {
 			return probe.NewError(e)
@@ -337,8 +344,8 @@ func deleteObjectPath(basePath, deletePath, bucket, object string) *probe.Error
 
 // DeleteObject - delete and object
 func (fs Filesystem) DeleteObject(bucket, object string) *probe.Error {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
+	fs.rwLock.Lock()
+	defer fs.rwLock.Unlock()
 
 	// check bucket name valid
 	if !IsValidBucketName(bucket) {
@@ -369,10 +376,10 @@ func (fs Filesystem) DeleteObject(bucket, object string) *probe.Error {
 		objectPath = fs.path + string(os.PathSeparator) + bucket + string(os.PathSeparator) + object
 	}
 	err := deleteObjectPath(bucketPath, objectPath, bucket, object)
+	if err != nil {
 		if os.IsNotExist(err.ToGoError()) {
 			return probe.NewError(ObjectNotFound{Bucket: bucket, Object: object})
 		}
-	if err != nil {
 		return err.Trace(bucketPath, objectPath, bucket, object)
 	}
 	return nil

pkg/fs/fs.go

@@ -31,7 +31,7 @@ type Filesystem struct {
 	path             string
 	minFreeDisk      int64
 	maxBuckets       int
-	lock             *sync.Mutex
+	rwLock           *sync.RWMutex
 	multiparts       *Multiparts
 	buckets          *Buckets
 	listServiceReqCh chan<- listServiceReq
@@ -59,7 +59,7 @@ type Multiparts struct {
 }
 
 // New instantiate a new donut
-func New(rootPath string) (Filesystem, *probe.Error) {
+func New(rootPath string, minFreeDisk int64, maxBuckets int) (Filesystem, *probe.Error) {
 	setFSBucketsConfigPath(filepath.Join(rootPath, "$buckets.json"))
 	setFSMultipartsConfigPath(filepath.Join(rootPath, "$multiparts-session.json"))
 
@@ -80,8 +80,11 @@ func New(rootPath string) (Filesystem, *probe.Error) {
 			return Filesystem{}, err.Trace()
 		}
 	}
-	// Initialize content db.
-	contentdb.Init()
+
+	// Initialize contentdb.
+	if e := contentdb.Init(); e != nil {
+		return Filesystem{}, probe.NewError(e)
+	}
 
 	var buckets *Buckets
 	buckets, err = loadBucketsMetadata()
@@ -98,16 +101,18 @@ func New(rootPath string) (Filesystem, *probe.Error) {
 			return Filesystem{}, err.Trace()
 		}
 	}
-	fs := Filesystem{lock: new(sync.Mutex)}
+	fs := Filesystem{
+		rwLock: &sync.RWMutex{},
+	}
 	fs.path = rootPath
 	fs.multiparts = multiparts
 	fs.buckets = buckets
 	/// Defaults
 
 	// maximum buckets to be listed from list buckets.
-	fs.maxBuckets = 1000
+	fs.maxBuckets = maxBuckets
 	// minium free disk required for i/o operations to succeed.
-	fs.minFreeDisk = 10
+	fs.minFreeDisk = minFreeDisk
 
 	// Start list goroutine.
 	if err = fs.listObjectsService(); err != nil {
@@ -116,20 +121,3 @@ func New(rootPath string) (Filesystem, *probe.Error) {
 	// Return here.
 	return fs, nil
 }
-
-// SetMinFreeDisk - set min free disk
-func (fs *Filesystem) SetMinFreeDisk(minFreeDisk int64) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
-	fs.minFreeDisk = minFreeDisk
-}
-
-// SetMaxBuckets - set total number of buckets supported, default is 100.
-func (fs *Filesystem) SetMaxBuckets(maxBuckets int) {
-	fs.lock.Lock()
-	defer fs.lock.Unlock()
-	if maxBuckets == 0 {
-		maxBuckets = 100
-	}
-	fs.maxBuckets = maxBuckets
-}

pkg/fs/fs_test.go

@@ -36,8 +36,7 @@ func (s *MySuite) TestAPISuite(c *C) {
 		path, e := ioutil.TempDir(os.TempDir(), "minio-")
 		c.Check(e, IsNil)
 		storageList = append(storageList, path)
-		store, err := New(path)
-		store.SetMinFreeDisk(0)
+		store, err := New(path, 0, 1000)
 		c.Check(err, IsNil)
 		return store
 	}

routers.go

@@ -143,10 +143,9 @@ func getNewWebAPI(conf cloudServerConfig) *WebAPI {
 
 // getNewCloudStorageAPI instantiate a new CloudStorageAPI.
 func getNewCloudStorageAPI(conf cloudServerConfig) CloudStorageAPI {
-	fs, err := fs.New(conf.Path)
+	fs, err := fs.New(conf.Path, conf.MinFreeDisk, conf.MaxBuckets)
 	fatalIf(err.Trace(), "Initializing filesystem failed.", nil)
 
-	fs.SetMinFreeDisk(conf.MinFreeDisk)
 	return CloudStorageAPI{
 		Filesystem: fs,
 		AccessLog:  conf.AccessLog,

server-main.go

@@ -58,6 +58,9 @@ EXAMPLES:
   4. Start minio server with minimum free disk threshold to 5%
       $ minio {{.Name}} min-free-disk 5% /home/shared/Pictures
 
+  5. Start minio server with minimum free disk threshold to 15% and support upto 2000 buckets.
+      $ minio {{.Name}} min-free-disk 15% /home/shared/Documents max-buckets 2000
+
 `,
 }
 
@@ -74,6 +77,7 @@ type cloudServerConfig struct {
 	/// FS options
 	Path        string // Path to export for cloud storage
 	MinFreeDisk int64  // Minimum free disk space for filesystem
+	MaxBuckets  int    // Maximum number of buckets suppported by filesystem.
 
 	/// TLS service
 	TLS      bool   // TLS on when certs are specified
@@ -284,9 +288,12 @@ func serverMain(c *cli.Context) {
 	}
 
 	var minFreeDisk int64
+	var maxBuckets int
 	minFreeDiskSet := false
+	maxBucketsSet := false
 	// Default
 	minFreeDisk = 10
+	maxBuckets = 1000
 
 	args := c.Args()
 	for len(args) >= 2 {
@@ -300,6 +307,16 @@ func serverMain(c *cli.Context) {
 			fatalIf(err.Trace(args.First()), "Invalid minium free disk size "+args.First()+" passed.", nil)
 			args = args.Tail()
 			minFreeDiskSet = true
+		case "max-buckets":
+			if maxBucketsSet {
+				fatalIf(probe.NewError(errInvalidArgument), "Maximum buckets should be set only once.", nil)
+			}
+			args = args.Tail()
+			var e error
+			maxBuckets, e = strconv.Atoi(args.First())
+			fatalIf(probe.NewError(e), "Invalid max buckets "+args.First()+" passed.", nil)
+			args = args.Tail()
+			maxBucketsSet = true
 		default:
 			cli.ShowCommandHelpAndExit(c, "server", 1) // last argument is exit code
 		}
@@ -318,6 +335,7 @@ func serverMain(c *cli.Context) {
 		SecretAccessKey: conf.Credentials.SecretAccessKey,
 		Path:            path,
 		MinFreeDisk:     minFreeDisk,
+		MaxBuckets:      maxBuckets,
 		TLS:             tls,
 		CertFile:        certFile,
 		KeyFile:         keyFile,