XL: Introduce new API StorageInfo. (#1770)

This is necessary for calculating the total storage
capacity from object layer. This value is also needed for
browser UI.

Buckets used to carry this information, this patch
deprecates this feature.

fs-v1.go

@@ -25,29 +25,31 @@ import (
 	"strings"
 	"sync"
 
+	"github.com/minio/minio/pkg/disk"
 	"github.com/minio/minio/pkg/mimedb"
 )
 
 // fsObjects - Implements fs object layer.
 type fsObjects struct {
 	storage            StorageAPI
+	physicalDisk       string
 	listObjectMap      map[listParams][]*treeWalkerFS
 	listObjectMapMutex *sync.Mutex
 }
 
 // newFSObjects - initialize new fs object layer.
-func newFSObjects(exportPath string) (ObjectLayer, error) {
+func newFSObjects(disk string) (ObjectLayer, error) {
 	var storage StorageAPI
 	var err error
-	if !strings.ContainsRune(exportPath, ':') || filepath.VolumeName(exportPath) != "" {
+	if !strings.ContainsRune(disk, ':') || filepath.VolumeName(disk) != "" {
 		// Initialize filesystem storage API.
-		storage, err = newPosix(exportPath)
+		storage, err = newPosix(disk)
 		if err != nil {
 			return nil, err
 		}
 	} else {
 		// Initialize rpc client storage API.
-		storage, err = newRPCClient(exportPath)
+		storage, err = newRPCClient(disk)
 		if err != nil {
 			return nil, err
 		}
@@ -60,11 +62,22 @@ func newFSObjects(exportPath string) (ObjectLayer, error) {
 	// Return successfully initialized object layer.
 	return fsObjects{
 		storage:            storage,
+		physicalDisk:       disk,
 		listObjectMap:      make(map[listParams][]*treeWalkerFS),
 		listObjectMapMutex: &sync.Mutex{},
 	}, nil
 }
 
+// StorageInfo - returns underlying storage statistics.
+func (fs fsObjects) StorageInfo() StorageInfo {
+	info, err := disk.GetInfo(fs.physicalDisk)
+	fatalIf(err, "Unable to get disk info "+fs.physicalDisk)
+	return StorageInfo{
+		Total: info.Total,
+		Free:  info.Free,
+	}
+}
+
 /// Bucket operations
 
 // MakeBucket - make a bucket.
@@ -92,8 +105,6 @@ func (fs fsObjects) GetBucketInfo(bucket string) (BucketInfo, error) {
 	return BucketInfo{
 		Name:    bucket,
 		Created: vi.Created,
-		Total:   vi.Total,
-		Free:    vi.Free,
 	}, nil
 }
 
@@ -113,8 +124,6 @@ func (fs fsObjects) ListBuckets() ([]BucketInfo, error) {
 		bucketInfos = append(bucketInfos, BucketInfo{
 			Name:    vol.Name,
 			Created: vol.Created,
-			Total:   vol.Total,
-			Free:    vol.Free,
 		})
 	}
 	sort.Sort(byBucketName(bucketInfos))