Support VFS2 save/restore.

Inode number consistency checks are now skipped in save/restore tests for
reasons described in greatest detail in StatTest.StateDoesntChangeAfterRename.
They pass in VFS1 due to the bug described in new test case
SimpleStatTest.DifferentFilesHaveDifferentDeviceInodeNumberPairs.

Fixes #1663

PiperOrigin-RevId: 338776148

1 files changed, 29 insertions, 23 deletions

diff --git a/test/util/save_util.cc b/test/util/save_util.cc
index 384d626f0..59d47e06e 100644
--- a/test/util/save_util.cc
+++ b/test/util/save_util.cc
@@ -21,35 +21,47 @@
 #include <atomic>
 #include <cerrno>
 
-#define GVISOR_COOPERATIVE_SAVE_TEST "GVISOR_COOPERATIVE_SAVE_TEST"
+#include "absl/types/optional.h"
 
 namespace gvisor {
 namespace testing {
 namespace {
 
-enum class CooperativeSaveMode {
-  kUnknown = 0,  // cooperative_save_mode is statically-initialized to 0
-  kAvailable,
-  kNotAvailable,
-};
-
-std::atomic<CooperativeSaveMode> cooperative_save_mode;
-
-bool CooperativeSaveEnabled() {
-  auto mode = cooperative_save_mode.load();
-  if (mode == CooperativeSaveMode::kUnknown) {
-    mode = (getenv(GVISOR_COOPERATIVE_SAVE_TEST) != nullptr)
-               ? CooperativeSaveMode::kAvailable
-               : CooperativeSaveMode::kNotAvailable;
-    cooperative_save_mode.store(mode);
+std::atomic<absl::optional<bool>> cooperative_save_present;
+std::atomic<absl::optional<bool>> random_save_present;
+
+bool CooperativeSavePresent() {
+  auto present = cooperative_save_present.load();
+  if (!present.has_value()) {
+    present = getenv("GVISOR_COOPERATIVE_SAVE_TEST") != nullptr;
+    cooperative_save_present.store(present);
+  }
+  return present.value();
+}
+
+bool RandomSavePresent() {
+  auto present = random_save_present.load();
+  if (!present.has_value()) {
+    present = getenv("GVISOR_RANDOM_SAVE_TEST") != nullptr;
+    random_save_present.store(present);
   }
-  return mode == CooperativeSaveMode::kAvailable;
+  return present.value();
 }
 
 std::atomic<int> save_disable;
 
 }  // namespace
 
+bool IsRunningWithSaveRestore() {
+  return CooperativeSavePresent() || RandomSavePresent();
+}
+
+void MaybeSave() {
+  if (CooperativeSavePresent() && save_disable.load() == 0) {
+    internal::DoCooperativeSave();
+  }
+}
+
 DisableSave::DisableSave() { save_disable++; }
 
 DisableSave::~DisableSave() { reset(); }
@@ -61,11 +73,5 @@ void DisableSave::reset() {
   }
 }
 
-namespace internal {
-bool ShouldSave() {
-  return CooperativeSaveEnabled() && (save_disable.load() == 0);
-}
-}  // namespace internal
-
 }  // namespace testing
 }  // namespace gvisor