fix(handlers): disable filesystem layer link metadata if the database is enabled

Fixes: gitlab-com/gl-infra/production#14260 (closed)

During a refactor, we removed migration mode, but we also removed logic which disables writing and reading for FS metadata: v3.71.0-gitlab...v3.73.0-gitlab

This caused serving blobs to fail here, since it tried to Stat their FS metadata: https://gitlab.com/gitlab-org/container-registry/-/blob/v3.73.0-gitlab/registry/storage/linkedblobstore.go#L76

registry/handlers/api_integration_test.go

@@ -671,10 +671,12 @@ func testManifestWithStorageError(t *testing.T, env *testEnv, imageName referenc
 func TestManifestAPI_Get_Schema2NotInDatabase(t *testing.T) {
 	skipDatabaseNotEnabled(t)
 
-	env1 := newTestEnv(t, withDBDisabled)
+	rootDir := t.TempDir()
+
+	env1 := newTestEnv(t, withDBDisabled, withFSDriver(rootDir))
 	defer env1.Shutdown()
 
-	env2 := newTestEnv(t)
+	env2 := newTestEnv(t, withFSDriver(rootDir))
 	defer env2.Shutdown()
 
 	tagName := "schema2"
@@ -726,10 +728,12 @@ func TestManifestAPI_Get_Schema2NotInDatabase(t *testing.T) {
 func TestManifestAPI_Put_Schema2WritesNoFilesystemBlobLinkMetadata(t *testing.T) {
 	skipDatabaseNotEnabled(t)
 
-	env1 := newTestEnv(t)
+	rootDir := t.TempDir()
+
+	env1 := newTestEnv(t, withFSDriver(rootDir))
 	defer env1.Shutdown()
 
-	env2 := newTestEnv(t, withDBDisabled)
+	env2 := newTestEnv(t, withDBDisabled, withFSDriver(rootDir))
 	defer env2.Shutdown()
 
 	tagName := "schema2"
@@ -1093,10 +1097,13 @@ func TestManifestAPI_Delete_Schema2ManifestNotInDatabase(t *testing.T) {
 	skipDatabaseNotEnabled(t)
 
 	// Setup
-	env1 := newTestEnv(t, withDBDisabled)
+
+	rootDir := t.TempDir()
+
+	env1 := newTestEnv(t, withDBDisabled, withFSDriver(rootDir))
 	defer env1.Shutdown()
 
-	env2 := newTestEnv(t, withDelete)
+	env2 := newTestEnv(t, withDelete, withFSDriver(rootDir))
 	defer env2.Shutdown()
 
 	tagName := "schema2deletetag"
@@ -1252,10 +1259,12 @@ func TestManifestAPI_Put_OCIImageIndexByTagManifestsNotPresentInDatabase(t *test
 
 	// Setup
 
-	env1 := newTestEnv(t, withDBDisabled)
+	rootDir := t.TempDir()
+
+	env1 := newTestEnv(t, withDBDisabled, withFSDriver(rootDir))
 	defer env1.Shutdown()
 
-	env2 := newTestEnv(t)
+	env2 := newTestEnv(t, withFSDriver(rootDir))
 	defer env2.Shutdown()
 
 	tagName := "ociindexmissingmanifeststag"