oplog prep gc fix (#216)

- Added option gc-validation to zenserver that does a check for missing references in all oplog post full GC. Enabled by default.
- Feature: Added option gc-validation to zen gc command to control reference validation. Enabled by default.
- Added more details in post GC log.
- Fixed race condition in oplog writes which could cause used attachments to be incorrectly removed by GC

1 files changed, 13 insertions, 10 deletions

diff --git a/src/zenstore/cache/cachedisklayer.cpp b/src/zenstore/cache/cachedisklayer.cpp
index 4aafb9828..93b639a51 100644
--- a/src/zenstore/cache/cachedisklayer.cpp
+++ b/src/zenstore/cache/cachedisklayer.cpp
@@ -3454,6 +3454,12 @@ ZenCacheDiskLayer::CacheBucket::CreateReferenceCheckers(GcCtx& Ctx)
 	return {new DiskBucketReferenceChecker(*this)};
 }
 
+std::vector<GcReferenceValidator*>
+ZenCacheDiskLayer::CacheBucket::CreateReferenceValidators(GcCtx& /*Ctx*/)
+{
+	return {};
+}
+
 void
 ZenCacheDiskLayer::CacheBucket::CompactState(RwLock::ExclusiveLockScope&,
 											 std::vector<BucketPayload>&  Payloads,
@@ -3594,12 +3600,10 @@ ZenCacheDiskLayer::GetOrCreateBucket(std::string_view InBucket)
 
 	CacheBucket* Result = Bucket.get();
 	m_Buckets.emplace(BucketName, std::move(Bucket));
-	m_UpdateCaptureLock.WithExclusiveLock([&]() {
-		if (m_CapturedBuckets)
-		{
-			m_CapturedBuckets->push_back(std::string(BucketName));
-		}
-	});
+	if (m_CapturedBuckets)
+	{
+		m_CapturedBuckets->push_back(std::string(BucketName));
+	}
 	return Result;
 }
 
@@ -4176,7 +4180,7 @@ ZenCacheDiskLayer::GetGcReferencerLocks()
 void
 ZenCacheDiskLayer::EnableUpdateCapture()
 {
-	m_UpdateCaptureLock.WithExclusiveLock([&]() {
+	m_Lock.WithExclusiveLock([&]() {
 		if (m_UpdateCaptureRefCounter == 0)
 		{
 			ZEN_ASSERT(!m_CapturedBuckets);
@@ -4193,7 +4197,7 @@ ZenCacheDiskLayer::EnableUpdateCapture()
 void
 ZenCacheDiskLayer::DisableUpdateCapture()
 {
-	m_UpdateCaptureLock.WithExclusiveLock([&]() {
+	m_Lock.WithExclusiveLock([&]() {
 		ZEN_ASSERT(m_CapturedBuckets);
 		ZEN_ASSERT(m_UpdateCaptureRefCounter > 0);
 		m_UpdateCaptureRefCounter--;
@@ -4205,9 +4209,8 @@ ZenCacheDiskLayer::DisableUpdateCapture()
 }
 
 std::vector<std::string>
-ZenCacheDiskLayer::GetCapturedBuckets()
+ZenCacheDiskLayer::GetCapturedBucketsLocked()
 {
-	RwLock::SharedLockScope _(m_UpdateCaptureLock);
 	if (m_CapturedBuckets)
 	{
 		return *m_CapturedBuckets;