fix: configFS might not be mounted if the directory exists (#479)

Author: ym

internal/usbgadget/changeset.go

@@ -48,7 +48,7 @@ var FileStateString = map[FileState]string{
 	FileStateFileContentMatch:       "FILE_CONTENT_MATCH",
 	FileStateFileWrite:              "FILE_WRITE",
 	FileStateMounted:                "MOUNTED",
-	FileStateMountedConfigFS:        "CONFIGFS_MOUNT",
+	FileStateMountedConfigFS:        "CONFIGFS_MOUNTED",
 	FileStateSymlink:                "SYMLINK",
 	FileStateSymlinkInOrderConfigFS: "SYMLINK_IN_ORDER_CONFIGFS",
 	FileStateTouch:                  "TOUCH",
@@ -155,6 +155,10 @@ func (f *RequestedFileChange) String() string {
 		s = fmt.Sprintf("unknown expected state %d for %s", f.ExpectedState, f.Path)
 	}
 
+	if len(f.Description) > 0 {
+		s += fmt.Sprintf(" (%s)", f.Description)
+	}
+
 	return s
 }
 

internal/usbgadget/config.go

@@ -2,7 +2,6 @@ package usbgadget
 
 import (
 	"fmt"
-	"os"
 	"os/exec"
 )
 
@@ -158,19 +157,9 @@ func (u *UsbGadget) OverrideGadgetConfig(itemKey string, itemAttr string, value
 }
 
 func mountConfigFS(path string) error {
-	_, err := os.Stat(path)
-	// TODO: check if it's mounted properly
-	if err == nil {
-		return nil
-	}
-
-	if os.IsNotExist(err) {
-		err = exec.Command("mount", "-t", "configfs", "none", path).Run()
-		if err != nil {
-			return fmt.Errorf("failed to mount configfs: %w", err)
-		}
-	} else {
-		return fmt.Errorf("unable to access usb gadget path: %w", err)
+	err := exec.Command("mount", "-t", "configfs", "none", path).Run()
+	if err != nil {
+		return fmt.Errorf("failed to mount configfs: %w", err)
 	}
 	return nil
 }

internal/usbgadget/config_tx.go

@@ -81,11 +81,12 @@ func (tx *UsbGadgetTransaction) addFileChange(component string, change Requested
 	return key
 }
 
-func (tx *UsbGadgetTransaction) mkdirAll(component string, path string, description string) string {
+func (tx *UsbGadgetTransaction) mkdirAll(component string, path string, description string, deps []string) string {
 	return tx.addFileChange(component, RequestedFileChange{
 		Path:          path,
 		ExpectedState: FileStateDirectory,
 		Description:   description,
+		DependsOn:     deps,
 	})
 }
 
@@ -131,14 +132,25 @@ func (tx *UsbGadgetTransaction) MountConfigFS() {
 }
 
 func (tx *UsbGadgetTransaction) CreateConfigPath() {
-	tx.mkdirAll("gadget", tx.configC1Path, "create config path")
+	tx.mkdirAll(
+		"gadget",
+		tx.configC1Path,
+		"create config path",
+		[]string{configFSPath},
+	)
 }
 
 func (tx *UsbGadgetTransaction) WriteGadgetConfig() {
 	// create kvm gadget path
-	tx.mkdirAll("gadget", tx.kvmGadgetPath, "create kvm gadget path")
+	tx.mkdirAll(
+		"gadget",
+		tx.kvmGadgetPath,
+		"create kvm gadget path",
+		[]string{tx.configC1Path},
+	)
 
 	deps := make([]string, 0)
+	deps = append(deps, tx.kvmGadgetPath)
 
 	for _, val := range tx.orderedConfigItems {
 		key := val.key
@@ -188,7 +200,10 @@ func (tx *UsbGadgetTransaction) writeGadgetItemConfig(item gadgetConfigItem, dep
 	files = append(files, deps...)
 
 	gadgetItemPath := joinPath(tx.kvmGadgetPath, item.path)
-	files = append(files, tx.mkdirAll(component, gadgetItemPath, "create gadget item directory"))
+	if gadgetItemPath != tx.kvmGadgetPath {
+		gadgetItemDir := tx.mkdirAll(component, gadgetItemPath, "create gadget item directory", files)
+		files = append(files, gadgetItemDir)
+	}
 
 	beforeChange := make([]string, 0)
 	disableGadgetItemKey := fmt.Sprintf("disable-%s", item.device)
@@ -231,7 +246,10 @@ func (tx *UsbGadgetTransaction) writeGadgetItemConfig(item gadgetConfigItem, dep
 	// create config directory if configAttrs are set
 	if len(item.configAttrs) > 0 {
 		configItemPath := joinPath(tx.configC1Path, item.configPath)
-		tx.mkdirAll(component, configItemPath, "create config item directory")
+		if configItemPath != tx.configC1Path {
+			configItemDir := tx.mkdirAll(component, configItemPath, "create config item directory", files)
+			files = append(files, configItemDir)
+		}
 		files = append(files, tx.writeGadgetAttrs(
 			configItemPath,
 			item.configAttrs,