diff --git a/filesystem/filesystem.go b/filesystem/filesystem.go
index 64a2e23..efc889c 100644
--- a/filesystem/filesystem.go
+++ b/filesystem/filesystem.go
@@ -88,6 +88,10 @@
 	// is ext4.
 	Type *string
 
+	// Identifies which partition this is for //visibility:any_system_image (and others) visibility
+	// checks, and will be used in the future for API surface checks.
+	Partition_type *string
+
 	// file_contexts file to make image. Currently, only ext4 is supported.
 	File_contexts *string `android:"path"`
 
@@ -175,6 +179,9 @@
 var pctx = android.NewPackageContext("android/soong/filesystem")
 
 func (f *filesystem) GenerateAndroidBuildActions(ctx android.ModuleContext) {
+	if !android.InList(f.PartitionType(), validPartitions) {
+		ctx.PropertyErrorf("partition_type", "partition_type must be one of %s, found: %s", validPartitions, f.PartitionType())
+	}
 	switch f.fsType(ctx) {
 	case ext4Type:
 		f.output = f.buildImageUsingBuildImage(ctx)
@@ -441,6 +448,10 @@
 		Text(android.PathForArbitraryOutput(ctx, stagingDir).String())
 }
 
+func (f *filesystem) PartitionType() string {
+	return proptools.StringDefault(f.properties.Partition_type, "system")
+}
+
 var _ android.AndroidMkEntriesProvider = (*filesystem)(nil)
 
 // Implements android.AndroidMkEntriesProvider
diff --git a/filesystem/system_image.go b/filesystem/system_image.go
index 34f4ffb..78ce377 100644
--- a/filesystem/system_image.go
+++ b/filesystem/system_image.go
@@ -43,6 +43,9 @@
 }
 
 func (s *systemImage) buildExtraFiles(ctx android.ModuleContext, root android.OutputPath) android.OutputPaths {
+	if s.filesystem.properties.Partition_type != nil {
+		ctx.PropertyErrorf("partition_type", "partition_type must be unset on an android_system_image module. It is assumed to be 'system'.")
+	}
 	lc := s.buildLinkerConfigFile(ctx, root)
 	// Add more files if needed
 	return []android.OutputPath{lc}