@@ -39,8 +39,9 @@ func openNextAvailableLoopback(index int, sparseFile *osFile) (loopFile *osFile,

 			return nil, ErrAttachLoopbackDevice

 		}

-		// FIXME: Check here if target is a block device (in C: S_ISBLK(mode))

-		if fi.IsDir() {

+		if fi.Mode()&osModeDevice != osModeDevice {

+			utils.Errorf("Loopback device %s is not a block device.", target)

+			continue

 		}

 		// Open the targeted loopback (use OpenFile because Open sets O_CLOEXEC)

@@ -46,9 +46,10 @@ const (

 	sysSysIoctl = syscall.SYS_IOCTL

 	sysEBusy    = syscall.EBUSY

-	osORdOnly = os.O_RDONLY

-	osORdWr   = os.O_RDWR

-	osOCreate = os.O_CREATE

+	osORdOnly    = os.O_RDONLY

+	osORdWr      = os.O_RDWR

+	osOCreate    = os.O_CREATE

+	osModeDevice = os.ModeDevice

 )

 func toSysStatT(i interface{}) *sysStatT {