Make IsCorrupted and SetCorrupted thread-safe

Author: Andrei Nasonov

cloud/storage/core/libs/file_backed_containers/file_ring_buffer.cpp

@@ -15,6 +15,8 @@
 #include <util/system/compiler.h>
 #include <util/system/filemap.h>
 
+#include <atomic>
+
 namespace NCloud {
 
 namespace {
@@ -137,7 +139,7 @@ class TFileRingBuffer::TImpl
 private:
     const TFileRingBufferArgs Args;
     TFileMapFileRingBufferAccessor Accessor;
-    bool Corrupted = false;
+    std::atomic<bool> Corrupted = false;
 
     TEntryInfo CurrentAllocation = TEntryInfo::CreateInvalid();
     ui64 MaxObservedEntryByteCount = 0;
@@ -788,13 +790,13 @@ class TFileRingBuffer::TImpl
 
     bool IsCorrupted() const
     {
-        return Corrupted;
+        return Corrupted.load(std::memory_order_relaxed);
     }
 
     void SetCorrupted(const TString& message)
     {
-        if (!Corrupted) {
-            Corrupted = true;
+        auto prevValue = Corrupted.exchange(true);
+        if (!prevValue) {
             ReportFileRingBufferCorruptionDetectedError(
                 "Corruption detected in FileRingBuffer, path: " +
                 Args.FilePath + ", message: " + message);

cloud/storage/core/libs/file_backed_containers/file_ring_buffer.h

@@ -12,6 +12,7 @@ namespace NCloud {
 
 ////////////////////////////////////////////////////////////////////////////////
 
+// Non-thread safe
 class TFileRingBuffer
 {
 public:
@@ -170,7 +171,17 @@ class TFileRingBuffer
      */
     NProto::TError Visit(const TVisitor& visitor);
 
+    // This method is thread safe
     bool IsCorrupted() const;
+
+    /**
+     * Sets Corrupted flag and fires a critical event if the flag has not
+     * been previously set. Unsetting the flag is not possible.
+     *
+     * All further operations on the buffer will fail once the flag is set.
+     *
+     * This method is thread safe
+     */
     void SetCorrupted();
 
     ui64 GetRawCapacity() const;

cloud/storage/core/libs/file_backed_containers/file_ring_buffer_ut.cpp

@@ -1319,7 +1319,7 @@ Y_UNIT_TEST_SUITE(TFileRingBufferTest)
 
         {
             TFileRingBuffer rb(f.GetName(), len, 0, EVersion::V6);
-            UNIT_ASSERT(rb.PushBack("b"));
+            UNIT_ASSERT_VALUES_EQUAL(true, rb.PushBack("b"));
         }
     }
 }