Fix correctness and concurrency bugs found during code review

zenstore fixes:
- cas.cpp: GetFileCasResults Results param passed by value instead of reference (large chunk results were silently lost)
- structuredcachestore.cpp: MissCount unconditionally incremented (counted hits as misses)
- cacherpc.cpp: Wrong boolean in Incomplete response array (all entries marked incomplete)
- cachedisklayer.cpp: sizeof(sizeof(...)) in two validation checks computed sizeof(size_t) instead of struct size
- buildstore.cpp: Wrong hash tracked in GC key list (BlobHash pushed twice instead of MetadataHash)
- buildstore.cpp: Removed duplicate m_LastAccessTimeUpdateCount increment in PutBlob

zenserver fixes:
- httpbuildstore.cpp: Reversed subtraction in HTTP range calculation (unsigned underflow)
- hubservice.cpp: Deadlock in Provision() calling Wake() while holding m_Lock (extracted WakeLocked helper)
- zipfs.cpp: Data race in GetFile() lazy initialization (added RwLock with shared/exclusive paths)

Co-Authored-By: Claude Opus 4.6 <[email protected]>

9 files changed, 42 insertions, 20 deletions

diff --git a/src/zenserver/frontend/zipfs.cpp b/src/zenserver/frontend/zipfs.cpp
index f9c2bc8ff..42df0520f 100644
--- a/src/zenserver/frontend/zipfs.cpp
+++ b/src/zenserver/frontend/zipfs.cpp
@@ -149,13 +149,25 @@ ZipFs::ZipFs(IoBuffer&& Buffer)
 IoBuffer
 ZipFs::GetFile(const std::string_view& FileName) const
 {
-	FileMap::iterator Iter = m_Files.find(FileName);
-	if (Iter == m_Files.end())
 	{
-		return {};
+		RwLock::SharedLockScope _(m_FilesLock);
+
+		FileMap::const_iterator Iter = m_Files.find(FileName);
+		if (Iter == m_Files.end())
+		{
+			return {};
+		}
+
+		const FileItem& Item = Iter->second;
+		if (Item.GetSize() > 0)
+		{
+			return IoBuffer(IoBuffer::Wrap, Item.GetData(), Item.GetSize());
+		}
 	}
 
-	FileItem& Item = Iter->second;
+	RwLock::ExclusiveLockScope _(m_FilesLock);
+
+	FileItem& Item = m_Files.find(FileName)->second;
 	if (Item.GetSize() > 0)
 	{
 		return IoBuffer(IoBuffer::Wrap, Item.GetData(), Item.GetSize());
diff --git a/src/zenserver/frontend/zipfs.h b/src/zenserver/frontend/zipfs.h
index 1fa7da451..19f96567c 100644
--- a/src/zenserver/frontend/zipfs.h
+++ b/src/zenserver/frontend/zipfs.h
@@ -3,6 +3,7 @@
 #pragma once
 
 #include <zencore/iobuffer.h>
+#include <zencore/thread.h>
 
 #include <unordered_map>
 
@@ -20,6 +21,7 @@ public:
 private:
 	using FileItem = MemoryView;
 	using FileMap  = std::unordered_map<std::string_view, FileItem>;
+	mutable RwLock m_FilesLock;
 	FileMap mutable m_Files;
 	IoBuffer m_Buffer;
 };
diff --git a/src/zenserver/hub/hubservice.cpp b/src/zenserver/hub/hubservice.cpp
index 4d9da3a57..a00446a75 100644
--- a/src/zenserver/hub/hubservice.cpp
+++ b/src/zenserver/hub/hubservice.cpp
@@ -151,6 +151,7 @@ struct StorageServerInstance
 	inline uint16_t GetBasePort() const { return m_ServerInstance.GetBasePort(); }
 
 private:
+	void				  WakeLocked();
 	RwLock				  m_Lock;
 	std::string			  m_ModuleId;
 	std::atomic<bool>	  m_IsProvisioned{false};
@@ -211,7 +212,7 @@ StorageServerInstance::Provision()
 
 	if (m_IsHibernated)
 	{
-		Wake();
+		WakeLocked();
 	}
 	else
 	{
@@ -294,9 +295,14 @@ StorageServerInstance::Hibernate()
 void
 StorageServerInstance::Wake()
 {
-	// Start server in-place using existing data
-
 	RwLock::ExclusiveLockScope _(m_Lock);
+	WakeLocked();
+}
+
+void
+StorageServerInstance::WakeLocked()
+{
+	// Start server in-place using existing data
 
 	if (!m_IsHibernated)
 	{
diff --git a/src/zenserver/storage/buildstore/httpbuildstore.cpp b/src/zenserver/storage/buildstore/httpbuildstore.cpp
index f5ba30616..bf7afcc02 100644
--- a/src/zenserver/storage/buildstore/httpbuildstore.cpp
+++ b/src/zenserver/storage/buildstore/httpbuildstore.cpp
@@ -185,7 +185,7 @@ HttpBuildStoreService::GetBlobRequest(HttpRouterRequest& Req)
 	{
 		const HttpRange& Range		 = Ranges.front();
 		const uint64_t	 BlobSize	 = Blob.GetSize();
-		const uint64_t	 MaxBlobSize = Range.Start < BlobSize ? Range.Start - BlobSize : 0;
+		const uint64_t	 MaxBlobSize = Range.Start < BlobSize ? BlobSize - Range.Start : 0;
 		const uint64_t	 RangeSize	 = Min(Range.End - Range.Start + 1, MaxBlobSize);
 		if (Range.Start + RangeSize > BlobSize)
 		{
diff --git a/src/zenstore/buildstore/buildstore.cpp b/src/zenstore/buildstore/buildstore.cpp
index 04a0781d3..aa37e75fe 100644
--- a/src/zenstore/buildstore/buildstore.cpp
+++ b/src/zenstore/buildstore/buildstore.cpp
@@ -266,13 +266,12 @@ BuildStore::PutBlob(const IoHash& BlobHash, const IoBuffer& Payload)
 			m_BlobLookup.insert({BlobHash, NewBlobIndex});
 		}
 
-		m_LastAccessTimeUpdateCount++;
 		if (m_TrackedBlobKeys)
 		{
 			m_TrackedBlobKeys->push_back(BlobHash);
 			if (MetadataHash != IoHash::Zero)
 			{
-				m_TrackedBlobKeys->push_back(BlobHash);
+				m_TrackedBlobKeys->push_back(MetadataHash);
 			}
 		}
 	}
diff --git a/src/zenstore/cache/cachedisklayer.cpp b/src/zenstore/cache/cachedisklayer.cpp
index ead7e4f3a..b73b3e6fb 100644
--- a/src/zenstore/cache/cachedisklayer.cpp
+++ b/src/zenstore/cache/cachedisklayer.cpp
@@ -626,7 +626,7 @@ BucketManifestSerializer::ReadSidecarFile(RwLock::ExclusiveLockScope&								  B
 		return false;
 	}
 
-	const uint64_t ExpectedEntryCount = (FileSize - sizeof(sizeof(BucketMetaHeader))) / sizeof(ManifestData);
+	const uint64_t ExpectedEntryCount = (FileSize - sizeof(BucketMetaHeader)) / sizeof(ManifestData);
 	if (Header.EntryCount > ExpectedEntryCount)
 	{
 		ZEN_WARN(
@@ -1057,7 +1057,7 @@ ZenCacheDiskLayer::CacheBucket::ReadIndexFile(RwLock::ExclusiveLockScope&, const
 		return 0;
 	}
 
-	const uint64_t ExpectedEntryCount = (FileSize - sizeof(sizeof(cache::impl::CacheBucketIndexHeader))) / sizeof(DiskIndexEntry);
+	const uint64_t ExpectedEntryCount = (FileSize - sizeof(cache::impl::CacheBucketIndexHeader)) / sizeof(DiskIndexEntry);
 	if (Header.EntryCount > ExpectedEntryCount)
 	{
 		return 0;
diff --git a/src/zenstore/cache/cacherpc.cpp b/src/zenstore/cache/cacherpc.cpp
index 94abcf547..e1fd0a3e6 100644
--- a/src/zenstore/cache/cacherpc.cpp
+++ b/src/zenstore/cache/cacherpc.cpp
@@ -966,7 +966,7 @@ CacheRpcHandler::HandleRpcGetCacheRecords(const CacheRequestContext& Context, Cb
 				}
 				else
 				{
-					ResponseObject.AddBool(true);
+					ResponseObject.AddBool(false);
 				}
 			}
 			ResponseObject.EndArray();
diff --git a/src/zenstore/cache/structuredcachestore.cpp b/src/zenstore/cache/structuredcachestore.cpp
index 52b494e45..4e8475293 100644
--- a/src/zenstore/cache/structuredcachestore.cpp
+++ b/src/zenstore/cache/structuredcachestore.cpp
@@ -608,7 +608,10 @@ ZenCacheStore::GetBatch::Commit()
 				m_CacheStore.m_HitCount++;
 				OpScope.SetBytes(Result.Value.GetSize());
 			}
-			m_CacheStore.m_MissCount++;
+			else
+			{
+				m_CacheStore.m_MissCount++;
+			}
 		}
 	}
 }
diff --git a/src/zenstore/cas.cpp b/src/zenstore/cas.cpp
index ed017988f..7402d92d3 100644
--- a/src/zenstore/cas.cpp
+++ b/src/zenstore/cas.cpp
@@ -300,12 +300,12 @@ GetCompactCasResults(CasContainerStrategy&				  Strategy,
 };
 
 static void
-GetFileCasResults(FileCasStrategy&					  Strategy,
-				  CasStore::InsertMode				  Mode,
-				  std::span<IoBuffer>				  Data,
-				  std::span<IoHash>					  ChunkHashes,
-				  std::span<size_t>					  Indexes,
-				  std::vector<CasStore::InsertResult> Results)
+GetFileCasResults(FileCasStrategy&					   Strategy,
+				  CasStore::InsertMode				   Mode,
+				  std::span<IoBuffer>				   Data,
+				  std::span<IoHash>					   ChunkHashes,
+				  std::span<size_t>					   Indexes,
+				  std::vector<CasStore::InsertResult>& Results)
 {
 	for (size_t Index : Indexes)
 	{