nodeserver: Take check for existing fsType out of ProvisionDevice

This check is needed only if called from StageVolume,
so lets make it in StageVolume, giving possibility to
return API error codes that follow spec better.

Author: okartau

pkg/pmem-csi-driver/nodeserver.go

@@ -344,6 +344,22 @@ func (ns *nodeServer) NodeStageVolume(ctx context.Context, req *csi.NodeStageVol
 		return nil, status.Error(codes.InvalidArgument, err.Error())
 	}
 
+	// Check does devicepath already contain a filesystem?
+	existingFsType, err := determineFilesystemType(device.Path)
+	if err != nil {
+		return nil, status.Error(codes.Internal, err.Error())
+	}
+
+	// what to do if existing file system is detected;
+	if existingFsType != "" {
+		// Is existing filesystem type same as requested?
+		if existingFsType == requestedFsType {
+			klog.V(4).Infof("Skip mkfs as %v file system already exists on %v", existingFsType, device.Path)
+		} else {
+			return nil, status.Error(codes.AlreadyExists, "File system with different type exists")
+		}
+	}
+
 	if err = ns.provisionDevice(device, requestedFsType); err != nil {
 		return nil, status.Error(codes.Internal, err.Error())
 	}
@@ -478,44 +494,25 @@ func (ns *nodeServer) createEphemeralDevice(ctx context.Context, req *csi.NodePu
 // and mounts at given targetPath.
 func (ns *nodeServer) provisionDevice(device *pmdmanager.PmemDeviceInfo, fsType string) error {
 	if fsType == "" {
-		// Default to ext4 filesystem
+		// Empty FsType means "unspecified" and we pick default, currently hard-coded to ext4
 		fsType = defaultFilesystem
 	}
 
-	// Check does devicepath already contain a filesystem?
-	existingFsType, err := determineFilesystemType(device.Path)
-	if err != nil {
-		return err
-	}
-
-	// what to do if existing file system is detected and is different from request;
-	// forced re-format would lead to loss of previous data, so we refuse.
-	if existingFsType != "" {
-		// Is existing filesystem type same as requested?
-		if existingFsType == fsType {
-			klog.V(4).Infof("Skip mkfs as %v file system already exists on %v", existingFsType, device.Path)
-		} else {
-			return fmt.Errorf("File system with different type(%s) exists, whereas requested type is '%s'", existingFsType, fsType)
-		}
+	cmd := ""
+	var args []string
+	// hard-code block size to 4k to avoid smaller values and trouble to dax mount option
+	if fsType == "ext4" {
+		cmd = "mkfs.ext4"
+		args = []string{"-b 4096", "-F", device.Path}
+	} else if fsType == "xfs" {
+		cmd = "mkfs.xfs"
+		args = []string{"-b", "size=4096", "-f", device.Path}
 	} else {
-		// no existing file system, make fs
-		// Empty FsType means "unspecified" and we pick default, currently hard-codes to ext4
-		cmd := ""
-		var args []string
-		// hard-code block size to 4k to avoid smaller values and trouble to dax mount option
-		if fsType == "ext4" {
-			cmd = "mkfs.ext4"
-			args = []string{"-b 4096", "-F", device.Path}
-		} else if fsType == "xfs" {
-			cmd = "mkfs.xfs"
-			args = []string{"-b", "size=4096", "-f", device.Path}
-		} else {
-			return fmt.Errorf("Unsupported filesystem '%s'. Supported filesystems types: 'xfs', 'ext4'", fsType)
-		}
-		output, err := pmemexec.RunCommand(cmd, args...)
-		if err != nil {
-			return fmt.Errorf("mkfs failed: %s", output)
-		}
+		return fmt.Errorf("Unsupported filesystem '%s'. Supported filesystems types: 'xfs', 'ext4'", fsType)
+	}
+	output, err := pmemexec.RunCommand(cmd, args...)
+	if err != nil {
+		return fmt.Errorf("mkfs failed: %s", output)
 	}
 
 	return nil