Handle ERROR_INVALID_PARAMETER error for GetVolumeInformationW win32 …

…api (#164)

* fix

* ignore error

CHANGELOG.md

@@ -15,6 +15,12 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Deprecated
 
+## [0.14.2]
+
+### Fixed
+
+- Fix again unsupported devices for filesystem. [#164](https://github.com/elastic/gosigar/pull/164)
+
 ## [0.14.1]
 
 ### Fixed

sigar_windows.go

@@ -130,7 +130,6 @@ func (self *FileSystemList) Get() error {
 	if err != nil {
 		return errors.Wrap(err, "GetAccessPaths failed")
 	}
-
 	for _, drive := range drives {
 		dt, err := windows.GetDriveType(drive)
 		if err != nil {
@@ -140,14 +139,12 @@ func (self *FileSystemList) Get() error {
 		if err != nil {
 			return errors.Wrapf(err, "GetFilesystemType failed")
 		}
-		if fsType != "" {
-			self.List = append(self.List, FileSystem{
-				DirName:     drive,
-				DevName:     drive,
-				TypeName:    dt.String(),
-				SysTypeName: fsType,
-			})
-		}
+		self.List = append(self.List, FileSystem{
+			DirName:     drive,
+			DevName:     drive,
+			TypeName:    dt.String(),
+			SysTypeName: fsType,
+		})
 	}
 	return nil
 }

sys/windows/syscall_windows.go

@@ -346,21 +346,17 @@ func GetDriveType(rootPathName string) (DriveType, error) {
 // https://docs.microsoft.com/en-us/windows/win32/api/fileapi/nf-fileapi-getvolumeinformationw
 func GetFilesystemType(rootPathName string) (string, error) {
 	rootPathNamePtr, err := syscall.UTF16PtrFromString(rootPathName)
+	var systemType = "unavailable"
 	if err != nil {
 		return "", errors.Wrapf(err, "UTF16PtrFromString failed for rootPathName=%v", rootPathName)
 	}
-
 	buffer := make([]uint16, MAX_PATH+1)
+	// _GetVolumeInformation will fail for external drives like CD-ROM or other type with error codes as ERROR_NOT_READY. ERROR_INVALID_FUNCTION, ERROR_INVALID_PARAMETER, etc., these types of errors will be ignored
 	success, err := _GetVolumeInformation(rootPathNamePtr, nil, 0, nil, nil, nil, &buffer[0], MAX_PATH)
-	// check if CD-ROM or other type that is not supported in GetVolumeInformation function
-	if err == ERROR_NOT_READY || err == ERROR_INVALID_FUNCTION {
-		return "", nil
-	}
-	if !success {
-		return "", errors.Wrap(err, "GetVolumeInformationW failed")
+	if success {
+		systemType = strings.ToLower(syscall.UTF16ToString(buffer))
 	}
-
-	return strings.ToLower(syscall.UTF16ToString(buffer)), nil
+	return systemType, nil
 }
 
 // EnumProcesses retrieves the process identifier for each process object in the