Reland "Create an empty system_ext partition for aosp_cf_*"

This relands https://r.android.com/3304080, with the following fixes
- Skip system_ext if the product (e.g. aosp_x86_64) does not support
  system_ext
- Remove analysis error from GetFsTypeFromString if the fs type is
  unsupported. Since we are autogenerating partitions now, internal
  module creation should be skipped instead of erroring out. `fsType`
  will raise an error for handcrafted filesystem modules that explicitly
  set fs type to an unsupported type.

Test: presubmits
Test: lunch aosp_x86_64-trunk_staging-userdebug && m nothing
Change-Id: I83e0c266aa3dc2ab830c0636e1a89d00f6906968

2 files changed, 30 insertions, 10 deletions

diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index 1e816a752..8c59df371 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -198,6 +198,10 @@ const (
 	unknown
 )
 
+func (fs fsType) IsUnknown() bool {
+	return fs == unknown
+}
+
 type FilesystemInfo struct {
 	// A text file containing the list of paths installed on the partition.
 	FileListFile android.Path
@@ -205,8 +209,7 @@ type FilesystemInfo struct {
 
 var FilesystemProvider = blueprint.NewProvider[FilesystemInfo]()
 
-func (f *filesystem) fsType(ctx android.ModuleContext) fsType {
-	typeStr := proptools.StringDefault(f.properties.Type, "ext4")
+func GetFsTypeFromString(ctx android.EarlyModuleContext, typeStr string) fsType {
 	switch typeStr {
 	case "ext4":
 		return ext4Type
@@ -217,11 +220,19 @@ func (f *filesystem) fsType(ctx android.ModuleContext) fsType {
 	case "cpio":
 		return cpioType
 	default:
-		ctx.PropertyErrorf("type", "%q not supported", typeStr)
 		return unknown
 	}
 }
 
+func (f *filesystem) fsType(ctx android.ModuleContext) fsType {
+	typeStr := proptools.StringDefault(f.properties.Type, "ext4")
+	fsType := GetFsTypeFromString(ctx, typeStr)
+	if fsType == unknown {
+		ctx.PropertyErrorf("type", "%q not supported", typeStr)
+	}
+	return fsType
+}
+
 func (f *filesystem) installFileName() string {
 	return f.BaseModuleName() + ".img"
 }
diff --git a/fsgen/filesystem_creator.go b/fsgen/filesystem_creator.go
index ed0c390ba..169722025 100644
--- a/fsgen/filesystem_creator.go
+++ b/fsgen/filesystem_creator.go
@@ -114,7 +114,11 @@ func filesystemCreatorFactory() android.Module {
 }
 
 func (f *filesystemCreator) createInternalModules(ctx android.LoadHookContext) {
-	for _, partitionType := range []string{"system"} {
+	partitionTypes := []string{"system"}
+	if ctx.DeviceConfig().SystemExtPath() == "system_ext" { // system_ext exists
+		partitionTypes = append(partitionTypes, "system_ext")
+	}
+	for _, partitionType := range partitionTypes {
 		if f.createPartition(ctx, partitionType) {
 			f.properties.Generated_partition_types = append(f.properties.Generated_partition_types, partitionType)
 		} else {
@@ -143,11 +147,14 @@ func (f *filesystemCreator) createDeviceModule(ctx android.LoadHookContext) {
 		Name: proptools.StringPtr(f.generatedModuleName(ctx.Config(), "device")),
 	}
 
-	// Currently, only the system partition module is created.
+	// Currently, only the system and system_ext partition module is created.
 	partitionProps := &filesystem.PartitionNameProperties{}
 	if android.InList("system", f.properties.Generated_partition_types) {
 		partitionProps.System_partition_name = proptools.StringPtr(f.generatedModuleNameForPartition(ctx.Config(), "system"))
 	}
+	if android.InList("system_ext", f.properties.Generated_partition_types) {
+		partitionProps.System_ext_partition_name = proptools.StringPtr(f.generatedModuleNameForPartition(ctx.Config(), "system_ext"))
+	}
 
 	ctx.CreateModule(filesystem.AndroidDeviceFactory, baseProps, partitionProps)
 }
@@ -183,11 +190,13 @@ func (f *filesystemCreator) createPartition(ctx android.LoadHookContext, partiti
 
 	fsProps.Partition_name = proptools.StringPtr(partitionType)
 	// BOARD_SYSTEMIMAGE_FILE_SYSTEM_TYPE
-	fsProps.Type = proptools.StringPtr(specificPartitionVars.BoardFileSystemType)
-	if *fsProps.Type != "ext4" {
-		// TODO(b/372522486): Support other FS types.
-		// Currently the android_filesystem module type only supports ext4:
-		// https://cs.android.com/android/platform/superproject/main/+/main:build/soong/filesystem/filesystem.go;l=416;drc=98047cfd07944b297a12d173453bc984806760d2
+	fsType := specificPartitionVars.BoardFileSystemType
+	if fsType == "" {
+		fsType = "ext4" //default
+	}
+	fsProps.Type = proptools.StringPtr(fsType)
+	if filesystem.GetFsTypeFromString(ctx, *fsProps.Type).IsUnknown() {
+		// Currently the android_filesystem module type only supports a handful of FS types like ext4, erofs
 		return false
 	}