Merged main

17 files changed, 185 insertions, 957 deletions

diff --git a/zencore/filesystem.cpp b/zencore/filesystem.cpp
index 9936f30ec..c3edf656e 100644
--- a/zencore/filesystem.cpp
+++ b/zencore/filesystem.cpp
@@ -842,9 +842,9 @@ TEST_CASE("filesystem")
 {
 	using namespace std::filesystem;
 
-	// GetExePath
+	// GetExePath -- this is not a great test as it's so dependent on where the this code gets linked in
 	path	   BinPath	   = GetRunningExecutablePath();
-	const bool ExpectedExe = BinPath.stem() == "zencore-test" || BinPath.stem() == "zenserver-test";
+	const bool ExpectedExe = BinPath.stem() == "zencore-test" || BinPath.stem() == "zenserver-test" || BinPath.stem() == "zenstore-test";
 	CHECK(ExpectedExe);
 	CHECK(is_regular_file(BinPath));
 
diff --git a/zencore/include/zencore/iobuffer.h b/zencore/include/zencore/iobuffer.h
index 110cd7d9d..5fbeaeaeb 100644
--- a/zencore/include/zencore/iobuffer.h
+++ b/zencore/include/zencore/iobuffer.h
@@ -372,7 +372,7 @@ class IoBufferBuilder
 
 public:
 	ZENCORE_API static IoBuffer MakeFromFile(const path_char_t* FileName, uint64_t Offset = 0, uint64_t Size = ~0ull);
-	ZENCORE_API static IoBuffer MakeFromTemporaryFile(const path_char_t* FileName);
+	ZENCORE_API static IoBuffer MakeFromTemporaryFile(const std::filesystem::path& FileName);
 	ZENCORE_API static IoBuffer MakeFromFileHandle(void* FileHandle, uint64_t Offset = 0, uint64_t Size = ~0ull);
 	inline static IoBuffer		MakeCloneFromMemory(const void* Ptr, size_t Sz) { return IoBuffer(IoBuffer::Clone, Ptr, Sz); }
 };
diff --git a/zencore/include/zencore/testutils.h b/zencore/include/zencore/testutils.h
index 72d985d5c..04648c6de 100644
--- a/zencore/include/zencore/testutils.h
+++ b/zencore/include/zencore/testutils.h
@@ -11,6 +11,7 @@ std::filesystem::path CreateTemporaryDirectory();
 class ScopedTemporaryDirectory
 {
 public:
+	explicit ScopedTemporaryDirectory(std::filesystem::path Directory);
 	ScopedTemporaryDirectory();
 	~ScopedTemporaryDirectory();
 
diff --git a/zencore/iobuffer.cpp b/zencore/iobuffer.cpp
index 04685defc..922c14f83 100644
--- a/zencore/iobuffer.cpp
+++ b/zencore/iobuffer.cpp
@@ -437,7 +437,7 @@ IoBufferBuilder::MakeFromFile(const path_char_t* FileName, uint64_t Offset, uint
 }
 
 IoBuffer
-IoBufferBuilder::MakeFromTemporaryFile(const path_char_t* FileName)
+IoBufferBuilder::MakeFromTemporaryFile(const std::filesystem::path& FileName)
 {
 	uint64_t FileSize;
 	void*	 Handle;
@@ -449,7 +449,7 @@ IoBufferBuilder::MakeFromTemporaryFile(const path_char_t* FileName)
 	// when a file has been written to a staging directory, and is going
 	// to be moved in place
 
-	HRESULT hRes = DataFile.Create(FileName, GENERIC_READ | DELETE, FILE_SHARE_READ | FILE_SHARE_DELETE, OPEN_EXISTING);
+	HRESULT hRes = DataFile.Create(FileName.native().c_str(), GENERIC_READ | DELETE, FILE_SHARE_READ | FILE_SHARE_DELETE, OPEN_EXISTING);
 
 	if (FAILED(hRes))
 	{
@@ -460,7 +460,7 @@ IoBufferBuilder::MakeFromTemporaryFile(const path_char_t* FileName)
 
 	Handle = DataFile.Detach();
 #	else
-	int Fd = open(FileName, O_RDONLY);
+	int Fd = open(FileName.native().c_str(), O_RDONLY);
 	if (Fd < 0)
 	{
 		return {};
diff --git a/zencore/string.cpp b/zencore/string.cpp
index 4bf0378b2..efa84ea73 100644
--- a/zencore/string.cpp
+++ b/zencore/string.cpp
@@ -341,7 +341,17 @@ NiceBytesToBuffer(uint64_t Num, std::span<char> Buffer)
 size_t
 NiceByteRateToBuffer(uint64_t Num, uint64_t ElapsedMs, std::span<char> Buffer)
 {
-	size_t n = NiceNumGeneral(Num * 1000 / ElapsedMs, Buffer, kNicenumBytes);
+	size_t n = 0;
+
+	if (ElapsedMs)
+	{
+		n = NiceNumGeneral(Num * 1000 / ElapsedMs, Buffer, kNicenumBytes);
+	}
+	else
+	{
+		Buffer[n++] = '0';
+		Buffer[n++] = 'B';
+	}
 
 	Buffer[n++] = '/';
 	Buffer[n++] = 's';
diff --git a/zencore/testutils.cpp b/zencore/testutils.cpp
index 78957cbcf..dbc3ab5af 100644
--- a/zencore/testutils.cpp
+++ b/zencore/testutils.cpp
@@ -26,6 +26,13 @@ ScopedTemporaryDirectory::ScopedTemporaryDirectory() : m_RootPath(CreateTemporar
 {
 }
 
+ScopedTemporaryDirectory::ScopedTemporaryDirectory(std::filesystem::path Directory) : m_RootPath(Directory)
+{
+	std::error_code Ec;
+	std::filesystem::remove_all(Directory, Ec);
+	std::filesystem::create_directories(Directory);
+}
+
 ScopedTemporaryDirectory::~ScopedTemporaryDirectory()
 {
 	std::error_code Ec;
diff --git a/zenserver/projectstore.cpp b/zenserver/projectstore.cpp
index 5c4983472..f14bc7896 100644
--- a/zenserver/projectstore.cpp
+++ b/zenserver/projectstore.cpp
@@ -1403,7 +1403,7 @@ HttpProjectService::HttpProjectService(CasStore& Store, ProjectStore* Projects)
 				{
 					return SharedBuffer(std::move(Data));
 				}
-				else if (Data = IoBufferBuilder::MakeFromTemporaryFile(AttachmentPath.native().c_str()))
+				else if (Data = IoBufferBuilder::MakeFromTemporaryFile(AttachmentPath))
 				{
 					return SharedBuffer(std::move(Data));
 				}
diff --git a/zenserver/vfs.cpp b/zenserver/vfs.cpp
deleted file mode 100644
index fcc9a71f8..000000000
--- a/zenserver/vfs.cpp
+++ /dev/null
@@ -1,900 +0,0 @@
-// Copyright Epic Games, Inc. All Rights Reserved.
-
-#include "vfs.h"
-
-#if ZEN_WITH_VFS
-#	include <zencore/except.h>
-#	include <zencore/filesystem.h>
-#	include <zencore/stream.h>
-#	include <zencore/windows.h>
-#	include <zencore/logging.h>
-#	include <zenstore/CAS.h>
-
-#	include <map>
-
-#	include <atlfile.h>
-#	include <projectedfslib.h>
-
-#	pragma comment(lib, "projectedfslib.lib")
-
-namespace zen {
-
-//////////////////////////////////////////////////////////////////////////
-
-struct ProjFsCliOptions
-{
-	bool		IsDebug = false;
-	bool		IsClean = false;
-	std::string CasSpec;
-	std::string ManifestSpec;
-	std::string MountPoint;
-};
-
-struct GuidHasher
-{
-	size_t operator()(const GUID& Guid) const
-	{
-		static_assert(sizeof(GUID) == (sizeof(size_t) * 2));
-
-		const size_t* Ptr = reinterpret_cast<const size_t*>(&Guid);
-
-		return Ptr[0] ^ Ptr[1];
-	}
-};
-
-class ProjfsNamespace
-{
-public:
-	HRESULT Initialize(const char* SnapshotSpec, const char* CasSpec)
-	{
-		std::filesystem::path ManifestSpec = zen::ManifestSpecToPath(SnapshotSpec);
-
-		CAtlFile ManifestFile;
-		HRESULT	 hRes = ManifestFile.Create(ManifestSpec.c_str(), GENERIC_READ, FILE_SHARE_READ, OPEN_EXISTING);
-		if (FAILED(hRes))
-		{
-			ZEN_ERROR("MANIFEST NOT FOUND!");  // TODO: add context
-
-			return hRes;
-		}
-
-		ULONGLONG FileLength = 0;
-		ManifestFile.GetSize(FileLength);
-
-		std::vector<uint8_t> Data;
-		Data.resize(FileLength);
-
-		ManifestFile.Read(Data.data(), (DWORD)Data.size());
-
-		zen::MemoryInStream MemoryStream(Data.data(), Data.size());
-
-		ReadManifest(/* out */ m_Manifest, MemoryStream);
-
-		uint64_t TotalBytes = 0;
-		uint64_t TotalFiles = 0;
-
-		m_Manifest.Root.VisitFiles([&](const zen::LeafNode& Node) {
-			TotalBytes += Node.FileSize;
-			TotalFiles++;
-		});
-
-		m_FileByteCount = TotalBytes;
-		m_FileCount		= TotalFiles;
-
-		// CAS root
-
-		zen::CasStoreConfiguration Config;
-		Config.RootDirectory = CasSpec;
-		m_CasStore->Initialize(Config);
-
-		return S_OK;
-	}
-
-	struct LookupResult
-	{
-		const zen::TreeNode* TreeNode = nullptr;
-		const zen::LeafNode* LeafNode = nullptr;
-	};
-
-	bool IsOnCasDrive(const char* Path)
-	{
-		ZEN_UNUSED(Path);
-
-		// TODO: programmatically determine of CAS and workspace path is on same drive!
-		return true;
-	}
-
-	LookupResult LookupNode(const std::wstring& Name) const
-	{
-		if (Name.empty())
-			return {nullptr};
-
-		zen::ExtendableWideStringBuilder<MAX_PATH> LocalName;
-		LocalName.Append(Name.c_str());
-
-		// Split components
-
-		const wchar_t* PathComponents[MAX_PATH / 2];
-		size_t		   PathComponentCount = 0;
-
-		const size_t Length = Name.length();
-
-		wchar_t* Base	 = LocalName.Data();
-		wchar_t* itStart = Base;
-
-		for (int i = 0; i < Length; ++i)
-		{
-			if (Base[i] == '\\')
-			{
-				// Component separator
-
-				Base[i] = L'\0';
-
-				PathComponents[PathComponentCount++] = itStart;
-
-				itStart = Base + i + 1;
-			}
-		}
-
-		// Push final component
-		if (Name.back() != L'\\')
-			PathComponents[PathComponentCount++] = itStart;
-
-		const zen::TreeNode* Node = &m_Manifest.Root;
-
-		if (PathComponentCount == 1)
-		{
-			if (PrjFileNameCompare(L"root", Name.c_str()) == 0)
-				return {Node};
-			else
-				return {nullptr};
-		}
-
-		for (size_t i = 1; i < PathComponentCount; ++i)
-		{
-			const auto& part = PathComponents[i];
-
-			const zen::TreeNode* NextNode = nullptr;
-
-			for (const zen::TreeNode& ChildNode : Node->Children)
-			{
-				if (PrjFileNameCompare(part, ChildNode.Name.c_str()) == 0)
-				{
-					NextNode = &ChildNode;
-					break;
-				}
-			}
-
-			if (NextNode)
-			{
-				Node = NextNode;
-
-				continue;
-			}
-
-			if (i == PathComponentCount - 1)
-			{
-				for (const zen::LeafNode& Leaf : Node->Leaves)
-				{
-					if (PrjFileNameCompare(part, Leaf.Name.c_str()) == 0)
-						return {nullptr, &Leaf};
-				}
-			}
-
-			return {nullptr};
-		}
-
-		return {Node};
-	}
-
-	const zen::SnapshotManifest& Manifest() const { return m_Manifest; }
-	zen::CasStore&				 CasStore() { return *m_CasStore; }
-
-	uint64_t FileCount() const { return m_FileCount; }
-	uint64_t FileByteCount() const { return m_FileByteCount; }
-
-private:
-	zen::SnapshotManifest		   m_Manifest;
-	std::unique_ptr<zen::CasStore> m_CasStore;
-
-	size_t m_FileCount	   = 0;
-	size_t m_FileByteCount = 0;
-};
-
-/** Projected File System Provider
- */
-
-class ProjfsProvider
-{
-public:
-	HRESULT ReadManifest(const char* ManifestSpec, const char* CasSpec);
-	HRESULT Initialize(std::filesystem::path RootPath, bool Clean);
-	void	Cleanup();
-
-	struct Callbacks;
-
-private:
-	static void DebugPrint(const char* Format, ...);
-
-	HRESULT StartDirEnum(const PRJ_CALLBACK_DATA* CallbackData, LPCGUID EnumerationId);
-	HRESULT EndDirEnum(const PRJ_CALLBACK_DATA* CallbackData, LPCGUID EnumerationId);
-	HRESULT GetDirEnum(const PRJ_CALLBACK_DATA*	   CallbackData,
-					   LPCGUID					   EnumerationId,
-					   LPCWSTR					   SearchExpression,
-					   PRJ_DIR_ENTRY_BUFFER_HANDLE DirEntryBufferHandle);
-	HRESULT GetPlaceholderInformation(const PRJ_CALLBACK_DATA* CallbackData);
-	HRESULT GetFileStream(const PRJ_CALLBACK_DATA* CallbackData, UINT64 ByteOffset, UINT32 Length);
-	HRESULT QueryFileName(const PRJ_CALLBACK_DATA* CallbackData);
-	HRESULT NotifyOperation(const PRJ_CALLBACK_DATA*	 CallbackData,
-							BOOLEAN						 IsDirectory,
-							PRJ_NOTIFICATION			 NotificationType,
-							LPCWSTR						 DestinationFileName,
-							PRJ_NOTIFICATION_PARAMETERS* OperationParameters);
-	void	CancelCommand(const PRJ_CALLBACK_DATA* CallbackData);
-
-	class DirectoryEnumeration;
-
-	zen::RwLock																	m_Lock;
-	std::unordered_map<GUID, std::unique_ptr<DirectoryEnumeration>, GuidHasher> m_DirectoryEnumerators;
-	ProjfsNamespace																m_Namespace;
-	PRJ_NAMESPACE_VIRTUALIZATION_CONTEXT										m_PrjContext		= nullptr;
-	bool																		m_GenerateFullFiles = false;
-};
-
-class ProjfsProvider::DirectoryEnumeration
-{
-public:
-	DirectoryEnumeration(ProjfsProvider* Outer, LPCGUID EnumerationGuid, const wchar_t* RelativePath)
-	: m_Outer(Outer)
-	, m_EnumerationId(*EnumerationGuid)
-	, m_Path(RelativePath)
-	{
-		ResetScan();
-	}
-
-	~DirectoryEnumeration() {}
-
-	void ResetScan()
-	{
-		// Restart enumeration from beginning
-
-		m_InfoIterator = m_Infos.end();
-
-		const ProjfsNamespace::LookupResult Lookup = m_Outer->m_Namespace.LookupNode(m_Path);
-
-		if (Lookup.TreeNode == nullptr && Lookup.LeafNode == nullptr)
-			return;
-
-		if (Lookup.TreeNode)
-		{
-			const zen::TreeNode* RootNode = Lookup.TreeNode;
-
-			// Populate info array
-
-			FILETIME FileTime;
-			GetSystemTimeAsFileTime(&FileTime);
-
-			for (const zen::TreeNode& ChildNode : RootNode->Children)
-			{
-				PRJ_FILE_BASIC_INFO Fbi{0};
-
-				Fbi.IsDirectory	 = TRUE;
-				Fbi.FileSize	 = 0;
-				Fbi.CreationTime = Fbi.LastAccessTime = Fbi.LastWriteTime = Fbi.ChangeTime = *((LARGE_INTEGER*)&FileTime);
-				Fbi.FileAttributes														   = FILE_ATTRIBUTE_DIRECTORY;
-
-				m_Infos.insert({ChildNode.Name, Fbi});
-			}
-
-			for (const zen::LeafNode& Leaf : RootNode->Leaves)
-			{
-				PRJ_FILE_BASIC_INFO Fbi{0};
-
-				Fbi.IsDirectory	   = FALSE;
-				Fbi.FileSize	   = Leaf.FileSize;
-				Fbi.FileAttributes = FILE_ATTRIBUTE_NORMAL;
-				Fbi.CreationTime = Fbi.LastAccessTime = Fbi.LastWriteTime = Fbi.ChangeTime =
-					*reinterpret_cast<const LARGE_INTEGER*>(&Leaf.FileModifiedTime);
-
-				m_Infos.insert({Leaf.Name, Fbi});
-			}
-		}
-
-		m_InfoIterator = m_Infos.begin();
-	}
-
-	HRESULT HandleRequest(_In_ const PRJ_CALLBACK_DATA*	   CallbackData,
-						  _In_opt_z_ LPCWSTR			   SearchExpression,
-						  _In_ PRJ_DIR_ENTRY_BUFFER_HANDLE DirEntryBufferHandle)
-	{
-		int EnumLimit = INT_MAX;
-
-		DebugPrint("ENUM '%S' -> pattern %S\n", CallbackData->FilePathName, SearchExpression);
-
-		HRESULT hRes = S_OK;
-
-		if (CallbackData->Flags & PRJ_CB_DATA_FLAG_ENUM_RESTART_SCAN)
-			ResetScan();
-
-		if (m_InfoIterator == m_Infos.end())
-			return S_OK;
-
-		if (CallbackData->Flags & PRJ_CB_DATA_FLAG_ENUM_RETURN_SINGLE_ENTRY)
-			EnumLimit = 1;
-
-		if (!m_Predicate)
-		{
-			if (SearchExpression)
-			{
-				bool isWild = PrjDoesNameContainWildCards(SearchExpression);
-
-				if (isWild)
-				{
-					if (SearchExpression[0] == L'*' && SearchExpression[1] == L'\0')
-					{
-						// Trivial accept -- no need to change predicate from the default
-					}
-					else
-					{
-						m_SearchExpression = SearchExpression;
-
-						m_Predicate = [this](LPCWSTR name) { return PrjFileNameMatch(name, m_SearchExpression.c_str()); };
-					}
-				}
-				else
-				{
-					if (SearchExpression[0])
-					{
-						// Look for specific name match (does this ever happen?)
-
-						m_SearchExpression = SearchExpression;
-
-						m_Predicate = [this](LPCWSTR name) { return PrjFileNameCompare(name, m_SearchExpression.c_str()) == 0; };
-					}
-				}
-			}
-		}
-
-		if (!m_Predicate)
-			m_Predicate = [](LPCWSTR) { return true; };
-
-		while (EnumLimit && m_InfoIterator != m_Infos.end())
-		{
-			auto& ThisNode = *m_InfoIterator;
-
-			auto& Name = ThisNode.first;
-			auto& Info = ThisNode.second;
-
-			if (m_Predicate(Name.c_str()))
-			{
-				hRes = PrjFillDirEntryBuffer(Name.c_str(), &Info, DirEntryBufferHandle);
-
-				if (hRes == HRESULT_FROM_WIN32(ERROR_INSUFFICIENT_BUFFER))
-					return S_OK;
-
-				if (FAILED(hRes))
-					break;
-
-				--EnumLimit;
-			}
-
-			++m_InfoIterator;
-		}
-
-		return hRes;
-	}
-
-private:
-	ProjfsProvider*	   m_Outer = nullptr;
-	const std::wstring m_Path;
-	const GUID		   m_EnumerationId;
-
-	// We need to maintain an ordered list of directory items since the
-	// ProjFS enumeration code gets confused otherwise and ends up producing
-	// multiple entries for the same file if there's a 'hydrated' version
-	// present.
-
-	struct FilenameLess
-	{
-		bool operator()(const std::wstring& Lhs, const std::wstring& Rhs) const { return PrjFileNameCompare(Lhs.c_str(), Rhs.c_str()) < 0; }
-	};
-
-	typedef std::map<std::wstring, PRJ_FILE_BASIC_INFO, FilenameLess> FileInfoMap_t;
-
-	FileInfoMap_t			m_Infos;
-	FileInfoMap_t::iterator m_InfoIterator;
-
-	std::wstring					  m_SearchExpression;
-	std::function<bool(LPCWSTR name)> m_Predicate;
-};
-
-//////////////////////////////////////////////////////////////////////////
-// Callback forwarding functions
-//
-
-struct ProjfsProvider::Callbacks
-{
-	static HRESULT CALLBACK StartDirEnum(_In_ const PRJ_CALLBACK_DATA* CallbackData, _In_ const GUID* EnumerationId)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->StartDirEnum(CallbackData, EnumerationId);
-	}
-
-	static HRESULT CALLBACK EndDirEnum(_In_ const PRJ_CALLBACK_DATA* CallbackData, _In_ LPCGUID EnumerationId)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->EndDirEnum(CallbackData, EnumerationId);
-	}
-
-	static HRESULT CALLBACK GetDirEnum(_In_ const PRJ_CALLBACK_DATA*	CallbackData,
-									   _In_ LPCGUID						EnumerationId,
-									   _In_opt_z_ LPCWSTR				SearchExpression,
-									   _In_ PRJ_DIR_ENTRY_BUFFER_HANDLE DirEntryBufferHandle)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)
-			->GetDirEnum(CallbackData, EnumerationId, SearchExpression, DirEntryBufferHandle);
-	}
-
-	static HRESULT CALLBACK GetPlaceholderInformation(_In_ const PRJ_CALLBACK_DATA* CallbackData)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->GetPlaceholderInformation(CallbackData);
-	}
-
-	static HRESULT CALLBACK GetFileStream(_In_ const PRJ_CALLBACK_DATA* CallbackData, _In_ UINT64 ByteOffset, _In_ UINT32 Length)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->GetFileStream(CallbackData, ByteOffset, Length);
-	}
-
-	static HRESULT CALLBACK QueryFileName(_In_ const PRJ_CALLBACK_DATA* CallbackData)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->QueryFileName(CallbackData);
-	}
-
-	static HRESULT CALLBACK NotifyOperation(_In_ const PRJ_CALLBACK_DATA* CallbackData,
-											_In_ BOOLEAN				  IsDirectory,
-											_In_ PRJ_NOTIFICATION		  NotificationType,
-											_In_opt_ LPCWSTR			  DestinationFileName,
-											_Inout_ PRJ_NOTIFICATION_PARAMETERS* OperationParameters)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)
-			->NotifyOperation(CallbackData, IsDirectory, NotificationType, DestinationFileName, OperationParameters);
-	}
-
-	static VOID CALLBACK CancelCommand(_In_ const PRJ_CALLBACK_DATA* CallbackData)
-	{
-		return reinterpret_cast<ProjfsProvider*>(CallbackData->InstanceContext)->CancelCommand(CallbackData);
-	}
-};
-
-// {6EEB94E4-3EF3-4C1C-AF15-D7FF64C19A4F}
-static const GUID ProviderGuid = {0x6eeb94e4, 0x3ef3, 0x4c1c, {0xaf, 0x15, 0xd7, 0xff, 0x64, 0xc1, 0x9a, 0x4f}};
-
-void
-ProjfsProvider::DebugPrint(const char* FmtString, ...)
-{
-	va_list vl;
-	va_start(vl, FmtString);
-
-#	if 0
-	vprintf(FmtString, vl);
-#	endif
-
-	va_end(vl);
-}
-
-HRESULT
-ProjfsProvider::Initialize(std::filesystem::path RootPath, bool Clean)
-{
-	PRJ_PLACEHOLDER_VERSION_INFO Pvi = {};
-	Pvi.ContentID[0]				 = 1;
-
-	if (Clean && std::filesystem::exists(RootPath))
-	{
-		printf("Cleaning '%S'...", RootPath.c_str());
-
-		bool success = zen::DeleteDirectories(RootPath);
-
-		if (!success)
-		{
-			printf(" retrying...");
-
-			success = zen::DeleteDirectories(RootPath);
-
-			// Failed?
-		}
-
-		printf(" done!\n");
-	}
-
-	bool RootDirectoryCreated = false;
-
-retry:
-	if (!std::filesystem::exists(RootPath))
-	{
-		zen::CreateDirectories(RootPath);
-	}
-
-	{
-		HRESULT hRes = PrjMarkDirectoryAsPlaceholder(RootPath.c_str(), nullptr, &Pvi, &ProviderGuid);
-
-		if (FAILED(hRes))
-		{
-			if (hRes == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND) && !RootDirectoryCreated)
-			{
-				printf("Creating '%S'...", RootPath.c_str());
-
-				std::filesystem::create_directories(RootPath.c_str());
-
-				RootDirectoryCreated = true;
-
-				printf("done!\n");
-
-				goto retry;
-			}
-			else if (hRes == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
-			{
-				ThrowSystemException(hRes, "Failed to initialize root placeholder");
-			}
-
-			// Ignore error, problems will be reported below anyway
-		}
-	}
-
-	// Callbacks
-
-	PRJ_CALLBACKS cbs = {};
-
-	cbs.StartDirectoryEnumerationCallback = Callbacks::StartDirEnum;
-	cbs.EndDirectoryEnumerationCallback	  = Callbacks::EndDirEnum;
-	cbs.GetDirectoryEnumerationCallback	  = Callbacks::GetDirEnum;
-	cbs.GetPlaceholderInfoCallback		  = Callbacks::GetPlaceholderInformation;
-	cbs.GetFileDataCallback				  = Callbacks::GetFileStream;
-	cbs.QueryFileNameCallback			  = Callbacks::QueryFileName;
-	cbs.NotificationCallback			  = Callbacks::NotifyOperation;
-	cbs.CancelCommandCallback			  = Callbacks::CancelCommand;
-
-	// Parameters
-
-	const PRJ_NOTIFY_TYPES dwNotifications = PRJ_NOTIFY_FILE_OPENED | PRJ_NOTIFY_NEW_FILE_CREATED | PRJ_NOTIFY_FILE_OVERWRITTEN |
-											 PRJ_NOTIFY_PRE_DELETE | PRJ_NOTIFY_PRE_RENAME | PRJ_NOTIFY_PRE_SET_HARDLINK |
-											 PRJ_NOTIFY_FILE_RENAMED | PRJ_NOTIFY_HARDLINK_CREATED |
-											 PRJ_NOTIFY_FILE_HANDLE_CLOSED_NO_MODIFICATION | PRJ_NOTIFY_FILE_HANDLE_CLOSED_FILE_MODIFIED |
-											 PRJ_NOTIFY_FILE_HANDLE_CLOSED_FILE_DELETED | PRJ_NOTIFY_FILE_PRE_CONVERT_TO_FULL;
-
-	PRJ_NOTIFICATION_MAPPING Mappings[] = {{dwNotifications, L"root"}};
-
-	PRJ_STARTVIRTUALIZING_OPTIONS SvOptions = {};
-
-	SvOptions.Flags						= PRJ_FLAG_NONE;
-	SvOptions.PoolThreadCount			= 8;
-	SvOptions.ConcurrentThreadCount		= 8;
-	SvOptions.NotificationMappings		= Mappings;
-	SvOptions.NotificationMappingsCount = 1;
-
-	HRESULT hRes = PrjStartVirtualizing(RootPath.c_str(), &cbs, this, &SvOptions, &m_PrjContext);
-
-	if (SUCCEEDED(hRes))
-	{
-		// Create dummy 'root' directory for now until I figure out how to
-		// invalidate entire trees (ProjFS won't allow invalidation of the
-		// entire provider tree).
-
-		PRJ_PLACEHOLDER_INFO pli{};
-		pli.FileBasicInfo.IsDirectory	 = TRUE;
-		pli.FileBasicInfo.FileAttributes = FILE_ATTRIBUTE_DIRECTORY;
-		pli.VersionInfo					 = Pvi;
-
-		hRes = PrjWritePlaceholderInfo(m_PrjContext, L"root", &pli, sizeof pli);
-	}
-
-	if (SUCCEEDED(hRes))
-	{
-		ZEN_INFO("Successfully mounted snapshot at '{}'!", WideToUtf8(RootPath.c_str()));
-	}
-	else
-	{
-		ZEN_INFO("Failed mounting snapshot at '{}'!", WideToUtf8(RootPath.c_str()));
-	}
-
-	return hRes;
-}
-
-void
-ProjfsProvider::Cleanup()
-{
-	PrjStopVirtualizing(m_PrjContext);
-}
-
-HRESULT
-ProjfsProvider::ReadManifest(const char* ManifestSpec, const char* CasSpec)
-{
-	printf("Initializing from manifest '%s'\n", ManifestSpec);
-
-	m_Namespace.Initialize(ManifestSpec, CasSpec);
-
-	return S_OK;
-}
-
-HRESULT
-ProjfsProvider::StartDirEnum(const PRJ_CALLBACK_DATA* CallbackData, LPCGUID EnumerationId)
-{
-	zen::RwLock::ExclusiveLockScope _(m_Lock);
-
-	m_DirectoryEnumerators[*EnumerationId] = std::make_unique<DirectoryEnumeration>(this, EnumerationId, CallbackData->FilePathName);
-
-	return S_OK;
-}
-
-HRESULT
-ProjfsProvider::EndDirEnum(const PRJ_CALLBACK_DATA* CallbackData, LPCGUID EnumerationId)
-{
-	ZEN_UNUSED(CallbackData);
-	ZEN_UNUSED(EnumerationId);
-
-	zen::RwLock::ExclusiveLockScope _(m_Lock);
-
-	m_DirectoryEnumerators.erase(*EnumerationId);
-
-	return S_OK;
-}
-
-HRESULT
-ProjfsProvider::GetDirEnum(const PRJ_CALLBACK_DATA*	   CallbackData,
-						   LPCGUID					   EnumerationId,
-						   LPCWSTR					   SearchExpression,
-						   PRJ_DIR_ENTRY_BUFFER_HANDLE DirEntryBufferHandle)
-{
-	DirectoryEnumeration* directoryEnumerator;
-
-	{
-		zen::RwLock::SharedLockScope _(m_Lock);
-
-		auto it = m_DirectoryEnumerators.find(*EnumerationId);
-
-		if (it == m_DirectoryEnumerators.end())
-			return E_FAIL;	// No enumerator associated with specified GUID
-
-		directoryEnumerator = (*it).second.get();
-	}
-
-	return directoryEnumerator->HandleRequest(CallbackData, SearchExpression, DirEntryBufferHandle);
-}
-
-HRESULT
-ProjfsProvider::GetPlaceholderInformation(const PRJ_CALLBACK_DATA* CallbackData)
-{
-	ProjfsNamespace::LookupResult result = m_Namespace.LookupNode(CallbackData->FilePathName);
-
-	if (auto Leaf = result.LeafNode)
-	{
-		PRJ_PLACEHOLDER_INFO PlaceholderInfo = {};
-
-		LARGE_INTEGER FileTime;
-		FileTime.QuadPart = Leaf->FileModifiedTime;
-
-		PlaceholderInfo.FileBasicInfo.ChangeTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.CreationTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.LastAccessTime = FileTime;
-		PlaceholderInfo.FileBasicInfo.LastWriteTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.FileSize		 = Leaf->FileSize;
-		PlaceholderInfo.FileBasicInfo.IsDirectory	 = 0;
-		PlaceholderInfo.FileBasicInfo.FileAttributes = FILE_ATTRIBUTE_NORMAL;
-
-		HRESULT hRes = PrjWritePlaceholderInfo(m_PrjContext, CallbackData->FilePathName, &PlaceholderInfo, sizeof PlaceholderInfo);
-
-		return hRes;
-	}
-
-	if (auto node = result.TreeNode)
-	{
-		PRJ_PLACEHOLDER_INFO PlaceholderInfo = {};
-
-		FILETIME ft;
-		GetSystemTimeAsFileTime(&ft);
-
-		LARGE_INTEGER FileTime;
-		FileTime.QuadPart = UINT64(ft.dwHighDateTime) << 32 | ft.dwLowDateTime;
-
-		PlaceholderInfo.FileBasicInfo.ChangeTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.CreationTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.LastAccessTime = FileTime;
-		PlaceholderInfo.FileBasicInfo.LastWriteTime	 = FileTime;
-		PlaceholderInfo.FileBasicInfo.IsDirectory	 = TRUE;
-		PlaceholderInfo.FileBasicInfo.FileAttributes = FILE_ATTRIBUTE_DIRECTORY;
-
-		HRESULT hRes = PrjWritePlaceholderInfo(m_PrjContext, CallbackData->FilePathName, &PlaceholderInfo, sizeof PlaceholderInfo);
-
-		return hRes;
-	}
-
-	return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
-}
-
-HRESULT
-ProjfsProvider::GetFileStream(const PRJ_CALLBACK_DATA* CallbackData, UINT64 ByteOffset, UINT32 Length)
-{
-	ProjfsNamespace::LookupResult result = m_Namespace.LookupNode(CallbackData->FilePathName);
-
-	if (const zen::LeafNode* leaf = result.LeafNode)
-	{
-		zen::CasStore& casStore = m_Namespace.CasStore();
-
-		const zen::IoHash& ChunkHash = leaf->ChunkHash;
-
-		zen::IoBuffer Chunk = casStore.FindChunk(ChunkHash);
-
-		if (!Chunk)
-			return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
-
-		if (m_GenerateFullFiles)
-		{
-			DWORD chunkSize = (DWORD)Chunk.Size();
-
-			zen::StringBuilder<66> b3string;
-			DebugPrint("GET FILE STREAM: %s -> %d '%S'\n", ChunkHash.ToHexString(b3string).c_str(), chunkSize, CallbackData->FilePathName);
-
-			// TODO: implement support for chunks > 4GB
-			ZEN_ASSERT(chunkSize == Chunk.Size());
-
-			HRESULT hRes = PrjWriteFileData(m_PrjContext, &CallbackData->DataStreamId, (PVOID)Chunk.Data(), 0, chunkSize);
-
-			return hRes;
-		}
-		else
-		{
-			HRESULT hRes = PrjWriteFileData(m_PrjContext,
-											&CallbackData->DataStreamId,
-											(PVOID)(reinterpret_cast<const uint8_t*>(Chunk.Data()) + ByteOffset),
-											ByteOffset,
-											Length);
-
-			return hRes;
-		}
-	}
-
-	return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
-}
-
-HRESULT
-ProjfsProvider::QueryFileName(const PRJ_CALLBACK_DATA* CallbackData)
-{
-	ProjfsNamespace::LookupResult result = m_Namespace.LookupNode(CallbackData->FilePathName);
-
-	if (result.LeafNode || result.TreeNode)
-		return S_OK;
-
-	return HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND);
-}
-
-HRESULT
-ProjfsProvider::NotifyOperation(const PRJ_CALLBACK_DATA*	 CallbackData,
-								BOOLEAN						 IsDirectory,
-								PRJ_NOTIFICATION			 NotificationType,
-								LPCWSTR						 DestinationFileName,
-								PRJ_NOTIFICATION_PARAMETERS* OperationParameters)
-{
-	ZEN_UNUSED(DestinationFileName);
-
-	switch (NotificationType)
-	{
-		case PRJ_NOTIFICATION_FILE_OPENED:
-			{
-				auto& pc = OperationParameters->PostCreate;
-
-				DebugPrint("*** OPEN: %s %08x '%S'\n", IsDirectory ? "(DIR)" : "-FILE", pc.NotificationMask, CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_NEW_FILE_CREATED:
-			{
-				auto& pc = OperationParameters->PostCreate;
-
-				DebugPrint("*** NEW : %s %08x '%S'\n", IsDirectory ? "(DIR)" : "-FILE", pc.NotificationMask, CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_FILE_OVERWRITTEN:
-			{
-				auto& pc = OperationParameters->PostCreate;
-
-				DebugPrint("*** OVER: %s %08x '%S'\n", IsDirectory ? "(DIR)" : "-FILE", pc.NotificationMask, CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_PRE_DELETE:
-			{
-				if (wcsstr(CallbackData->FilePathName, L"en-us"))
-					DebugPrint("*** PRE DELETE '%S'\n", CallbackData->FilePathName);
-
-				DebugPrint("*** PRE DELETE '%S'\n", CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_PRE_RENAME:
-			DebugPrint("*** PRE RENAME '%S'\n", CallbackData->FilePathName);
-			break;
-
-		case PRJ_NOTIFICATION_PRE_SET_HARDLINK:
-			DebugPrint("*** PRE SET HARDLINK '%S'\n", CallbackData->FilePathName);
-			break;
-
-		case PRJ_NOTIFICATION_FILE_RENAMED:
-			DebugPrint("*** FILE RENAMED '%S'\n", CallbackData->FilePathName);
-			break;
-
-		case PRJ_NOTIFICATION_HARDLINK_CREATED:
-			DebugPrint("*** HARDLINK RENAMED '%S'\n", CallbackData->FilePathName);
-			break;
-
-		case PRJ_NOTIFICATION_FILE_HANDLE_CLOSED_NO_MODIFICATION:
-			DebugPrint("*** FILE CLOSED NO CHANGE '%S'\n", CallbackData->FilePathName);
-			break;
-
-		case PRJ_NOTIFICATION_FILE_HANDLE_CLOSED_FILE_MODIFIED:
-			{
-				// const auto& handleClose = OperationParameters->FileDeletedOnHandleClose;
-
-				DebugPrint("*** FILE CLOSED MODIFIED '%S'\n", CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_FILE_HANDLE_CLOSED_FILE_DELETED:
-			{
-				// const auto& handleClose = OperationParameters->FileDeletedOnHandleClose;
-
-				DebugPrint("*** FILE CLOSED DELETED '%S'\n", CallbackData->FilePathName);
-			}
-			break;
-
-		case PRJ_NOTIFICATION_FILE_PRE_CONVERT_TO_FULL:
-			DebugPrint("*** FILE PRE CONVERT FULL '%S'\n", CallbackData->FilePathName);
-			break;
-	}
-
-	return S_OK;
-}
-
-void
-ProjfsProvider::CancelCommand(const PRJ_CALLBACK_DATA* CallbackData)
-{
-	ZEN_UNUSED(CallbackData);
-}
-
-//////////////////////////////////////////////////////////////////////////
-
-struct Vfs::VfsImpl
-{
-	void Initialize() { m_PrjProvider.Initialize("E:\\VFS_Test", /* clean */ true); }
-	void Start() {}
-	void Stop() {}
-
-private:
-	ProjfsProvider m_PrjProvider;
-};
-
-//////////////////////////////////////////////////////////////////////////
-
-Vfs::Vfs() : m_Impl(new VfsImpl)
-{
-}
-
-Vfs::~Vfs()
-{
-}
-
-void
-Vfs::Initialize()
-{
-	m_Impl->Initialize();
-}
-
-void
-Vfs::Start()
-{
-}
-
-void
-Vfs::Stop()
-{
-}
-
-}  // namespace zen
-#endif
\ No newline at end of file
diff --git a/zenserver/vfs.h b/zenserver/vfs.h
deleted file mode 100644
index 0d2ca6062..000000000
--- a/zenserver/vfs.h
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright Epic Games, Inc. All Rights Reserved.
-
-#pragma once
-
-#ifndef ZEN_WITH_VFS
-#	define ZEN_WITH_VFS 0
-#endif
-
-#if ZEN_WITH_VFS
-#	include <memory>
-
-namespace zen {
-
-/**
- * Virtual File System serving
- */
-
-class Vfs
-{
-public:
-	Vfs();
-	~Vfs();
-
-	void Initialize();
-
-	void Start();
-	void Stop();
-
-private:
-	struct VfsImpl;
-
-	std::unique_ptr<VfsImpl> m_Impl;
-};
-
-}  // namespace zen
-#endif
diff --git a/zenserver/zenserver.vcxproj b/zenserver/zenserver.vcxproj
index 7fad477a1..b670582e7 100644
--- a/zenserver/zenserver.vcxproj
+++ b/zenserver/zenserver.vcxproj
@@ -83,6 +83,7 @@
       <OptimizeReferences>true</OptimizeReferences>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <UACExecutionLevel>RequireAdministrator</UACExecutionLevel>
+      <DelayLoadDLLs>projectedfslib.dll;shell32.dll</DelayLoadDLLs>
     </Link>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'">
@@ -99,7 +100,7 @@
       <SubSystem>Console</SubSystem>
       <GenerateDebugInformation>true</GenerateDebugInformation>
       <UACExecutionLevel>RequireAdministrator</UACExecutionLevel>
-      <DelayLoadDLLs>projectedfslib.dll</DelayLoadDLLs>
+      <DelayLoadDLLs>projectedfslib.dll;shell32.dll</DelayLoadDLLs>
     </Link>
   </ItemDefinitionGroup>
   <ItemGroup>
@@ -127,7 +128,6 @@
     <ClInclude Include="targetver.h" />
     <ClInclude Include="upstream\upstreamcache.h" />
     <ClInclude Include="upstream\zen.h" />
-    <ClInclude Include="vfs.h" />
     <ClInclude Include="windows\service.h" />
   </ItemGroup>
   <ItemGroup>
@@ -151,7 +151,6 @@
     <ClCompile Include="experimental\usnjournal.cpp" />
     <ClCompile Include="upstream\upstreamcache.cpp" />
     <ClCompile Include="upstream\zen.cpp" />
-    <ClCompile Include="vfs.cpp" />
     <ClCompile Include="windows\service.cpp" />
     <ClCompile Include="zenserver.cpp" />
   </ItemGroup>
diff --git a/zenserver/zenserver.vcxproj.filters b/zenserver/zenserver.vcxproj.filters
index 04e639a33..b87fa0016 100644
--- a/zenserver/zenserver.vcxproj.filters
+++ b/zenserver/zenserver.vcxproj.filters
@@ -4,7 +4,6 @@
     <ClInclude Include="targetver.h" />
     <ClInclude Include="projectstore.h" />
     <ClInclude Include="casstore.h" />
-    <ClInclude Include="vfs.h" />
     <ClInclude Include="testing\launch.h" />
     <ClInclude Include="cache\cacheagent.h">
       <Filter>cache</Filter>
@@ -50,7 +49,6 @@
     <ClCompile Include="zenserver.cpp" />
     <ClCompile Include="projectstore.cpp" />
     <ClCompile Include="casstore.cpp" />
-    <ClCompile Include="vfs.cpp" />
     <ClCompile Include="cache\cacheagent.cpp">
       <Filter>cache</Filter>
     </ClCompile>
diff --git a/zenstore/basicfile.cpp b/zenstore/basicfile.cpp
index f41f04101..cfc77e2a5 100644
--- a/zenstore/basicfile.cpp
+++ b/zenstore/basicfile.cpp
@@ -143,6 +143,12 @@ BasicFile::StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<voi
 	}
 }
 
+void 
+BasicFile::Write(MemoryView Data, uint64_t FileOffset, std::error_code& Ec)
+{
+	Write(Data.GetData(), Data.GetSize(), FileOffset, Ec);
+}
+
 void
 BasicFile::Write(const void* Data, uint64_t Size, uint64_t FileOffset, std::error_code& Ec)
 {
@@ -177,6 +183,12 @@ BasicFile::Write(const void* Data, uint64_t Size, uint64_t FileOffset, std::erro
 }
 
 void
+BasicFile::Write(MemoryView Data, uint64_t FileOffset)
+{
+	Write(Data.GetData(), Data.GetSize(), FileOffset);
+}
+
+void
 BasicFile::Write(const void* Data, uint64_t Size, uint64_t Offset)
 {
 	std::error_code Ec;
diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index ee641b80a..f69ed6bdb 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -9,12 +9,15 @@
 #include <zencore/memory.h>
 #include <zencore/scopeguard.h>
 #include <zencore/string.h>
+#include <zencore/testing.h>
+#include <zencore/testutils.h>
 #include <zencore/thread.h>
 #include <zencore/uid.h>
 #include <zenstore/basicfile.h>
 
 #include <gsl/gsl-lite.hpp>
 
+#include <barrier>
 #include <filesystem>
 #include <functional>
 #include <unordered_map>
@@ -86,15 +89,19 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 	{
 		ShardingHelper Name(m_Config.RootDirectory.c_str(), ChunkHash);
 
+		const HANDLE ChunkFileHandle = FileRef.FileHandle;
+
 		auto DeletePayloadFileOnClose = [&] {
 			// This will cause the file to be deleted when the last handle to it is closed
 			FILE_DISPOSITION_INFO Fdi{};
 			Fdi.DeleteFile = TRUE;
-			BOOL Success   = SetFileInformationByHandle(FileRef.FileHandle, FileDispositionInfo, &Fdi, sizeof Fdi);
+			BOOL Success   = SetFileInformationByHandle(ChunkFileHandle, FileDispositionInfo, &Fdi, sizeof Fdi);
 
 			if (!Success)
 			{
-				ZEN_WARN("Failed to flag temporary payload file for deletion: '{}'", PathFromHandle(FileRef.FileHandle));
+				ZEN_WARN("Failed to flag temporary payload file '{}' for deletion: '{}'",
+						 PathFromHandle(ChunkFileHandle),
+						 GetLastErrorAsString());
 			}
 		};
 
@@ -118,6 +125,28 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 
 				return CasStore::InsertResult{.New = false};
 			}
+			else
+			{
+				if (hRes == HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND))
+				{
+					// Shard directory does not exist
+				}
+				else if (hRes == HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND))
+				{
+					// Shard directory exists, but not the file
+				}
+				else if (hRes == HRESULT_FROM_WIN32(ERROR_SHARING_VIOLATION))
+				{
+					 // Sharing violation, likely because we are trying to open a file
+					 // which has been renamed on another thread, and the file handle
+					 // used to rename it is still open. We handle this case below
+					 // instead of here
+				}
+				else
+				{
+					ZEN_INFO("Unexpected error opening file '{}': {}", WideToUtf8(Name.ShardedPath), hRes);
+				}
+			}
 		}
 
 		std::filesystem::path FullPath(Name.ShardedPath.c_str());
@@ -138,7 +167,7 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 
 		// Try to move file into place
 
-		BOOL Success = SetFileInformationByHandle(FileRef.FileHandle, FileRenameInfo, RenameInfo, BufferSize);
+		BOOL Success = SetFileInformationByHandle(ChunkFileHandle, FileRenameInfo, RenameInfo, BufferSize);
 
 		if (!Success)
 		{
@@ -150,7 +179,7 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 			auto InternalCreateDirectoryHandle = [&] {
 				return DirHandle.Create(FilePath.c_str(),
 										GENERIC_READ | GENERIC_WRITE,
-										FILE_SHARE_READ | FILE_SHARE_WRITE,
+										FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE,
 										OPEN_EXISTING,
 										FILE_FLAG_BACKUP_SEMANTICS);
 			};
@@ -163,6 +192,9 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 
 			if (FAILED(hRes))
 			{
+				// TODO: we can handle directory creation more intelligently and efficiently than
+				// this currently does
+
 				CreateDirectories(FilePath.c_str());
 
 				hRes = InternalCreateDirectoryHandle();
@@ -173,9 +205,9 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 				ThrowSystemException(hRes, "Failed to open shard directory '{}'"_format(FilePath));
 			}
 
-			// Retry
+			// Retry rename/move
 
-			Success = SetFileInformationByHandle(FileRef.FileHandle, FileRenameInfo, RenameInfo, BufferSize);
+			Success = SetFileInformationByHandle(ChunkFileHandle, FileRenameInfo, RenameInfo, BufferSize);
 		}
 
 		if (Success)
@@ -183,8 +215,17 @@ FileCasStrategy::InsertChunk(IoBuffer Chunk, const IoHash& ChunkHash)
 			return CasStore::InsertResult{.New = true};
 		}
 
+		const DWORD LastError = GetLastError();
+
+		if ((LastError == ERROR_FILE_EXISTS) || (LastError == ERROR_ALREADY_EXISTS))
+		{
+			DeletePayloadFileOnClose();
+
+			return CasStore::InsertResult{.New = false};
+		}
+
 		ZEN_WARN("rename of CAS payload file failed ('{}'), falling back to regular write for insert of {}",
-				 GetLastErrorAsString(),
+				 GetSystemErrorAsString(LastError),
 				 ChunkHash);
 
 		DeletePayloadFileOnClose();
@@ -445,4 +486,94 @@ FileCasStrategy::GarbageCollect(GcContext& GcCtx)
 	ZEN_UNUSED(GcCtx);
 }
 
+//////////////////////////////////////////////////////////////////////////
+
+#if ZEN_WITH_TESTS
+
+TEST_CASE("cas.file.move")
+{
+	using namespace fmt::literals;
+
+	ScopedTemporaryDirectory TempDir{"d:\\filecas_testdir"};
+
+	CasStoreConfiguration CasConfig;
+	CasConfig.RootDirectory = TempDir.Path() / "cas";
+
+	FileCasStrategy FileCas(CasConfig);
+
+	{
+		std::filesystem::path Payload1Path{TempDir.Path() / "payload_1"};
+
+		IoBuffer ZeroBytes{1024 * 1024};
+		IoHash	 ZeroHash = IoHash::HashBuffer(ZeroBytes);
+
+		BasicFile PayloadFile;
+		PayloadFile.Open(Payload1Path, true);
+		PayloadFile.Write(ZeroBytes, 0);
+		PayloadFile.Close();
+
+		IoBuffer Payload1 = IoBufferBuilder::MakeFromTemporaryFile(Payload1Path);
+
+		CasStore::InsertResult Result = FileCas.InsertChunk(Payload1, ZeroHash);
+		CHECK_EQ(Result.New, true);
+	}
+
+#	if 0
+	SUBCASE("stresstest")
+	{
+		std::vector<IoHash> PayloadHashes;
+
+		const int kWorkers = 64;
+		const int kItemCount = 128;
+
+		for (int w = 0; w < kWorkers; ++w)
+		{
+			for (int i = 0; i < kItemCount; ++i)
+			{
+				IoBuffer Payload{1024};
+				*reinterpret_cast<int*>(Payload.MutableData()) = i;
+				PayloadHashes.push_back(IoHash::HashBuffer(Payload));
+
+				std::filesystem::path PayloadPath{TempDir.Path() / "payload_{}_{}"_format(w, i)};
+				WriteFile(PayloadPath, Payload);
+			}
+		}
+
+		std::barrier Sync{kWorkers};
+
+		auto PopulateAll = [&](int w) {
+			std::vector<IoBuffer> Buffers;
+
+			for (int i = 0; i < kItemCount; ++i)
+			{
+				std::filesystem::path PayloadPath{TempDir.Path() / "payload_{}_{}"_format(w, i)};
+				IoBuffer			  Payload = IoBufferBuilder::MakeFromTemporaryFile(PayloadPath);
+				Buffers.push_back(Payload);
+				Sync.arrive_and_wait();
+				CasStore::InsertResult Result = FileCas.InsertChunk(Payload, PayloadHashes[i]);
+			}
+		};
+
+		std::vector<std::jthread> Threads;
+
+		for (int i = 0; i < kWorkers; ++i)
+		{
+			Threads.push_back(std::jthread(PopulateAll, i));
+		}
+
+		for (std::jthread& Thread : Threads)
+		{
+			Thread.join();
+		}
+	}
+#	endif
+}
+
+#endif
+
+void
+filecas_forcelink()
+{
+}
+
 }  // namespace zen
diff --git a/zenstore/filecas.h b/zenstore/filecas.h
index db21502c6..14314ce52 100644
--- a/zenstore/filecas.h
+++ b/zenstore/filecas.h
@@ -57,4 +57,6 @@ private:
 	};
 };
 
+void filecas_forcelink();
+
 }  // namespace zen
diff --git a/zenstore/include/zenstore/CAS.h b/zenstore/include/zenstore/CAS.h
index d0698df7f..86e7e78d9 100644
--- a/zenstore/include/zenstore/CAS.h
+++ b/zenstore/include/zenstore/CAS.h
@@ -21,7 +21,7 @@ namespace zen {
 
 struct CasStoreConfiguration
 {
-	// Root directory for CAS store -- if not specified a default folder will be assigned in 'Documents\zen'
+	// Root directory for CAS store
 	std::filesystem::path RootDirectory;
 
 	// Threshold below which values are considered 'tiny' and managed using the 'tiny values' strategy
diff --git a/zenstore/include/zenstore/basicfile.h b/zenstore/include/zenstore/basicfile.h
index fad4a33e1..7ae35dea6 100644
--- a/zenstore/include/zenstore/basicfile.h
+++ b/zenstore/include/zenstore/basicfile.h
@@ -36,6 +36,8 @@ public:
 	void	 Read(void* Data, uint64_t Size, uint64_t FileOffset);
 	void	 StreamFile(std::function<void(const void* Data, uint64_t Size)>&& ChunkFun);
 	void	 StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<void(const void* Data, uint64_t Size)>&& ChunkFun);
+	void	 Write(MemoryView Data, uint64_t FileOffset);
+	void	 Write(MemoryView Data, uint64_t FileOffset, std::error_code& Ec);
 	void	 Write(const void* Data, uint64_t Size, uint64_t FileOffset);
 	void	 Write(const void* Data, uint64_t Size, uint64_t FileOffset, std::error_code& Ec);
 	void	 Flush();
diff --git a/zenstore/zenstore.cpp b/zenstore/zenstore.cpp
index cd16e5634..d852fa64b 100644
--- a/zenstore/zenstore.cpp
+++ b/zenstore/zenstore.cpp
@@ -4,6 +4,7 @@
 
 #include <zenstore/CAS.h>
 #include <zenstore/basicfile.h>
+#include "filecas.h"
 
 namespace zen {
 
@@ -12,6 +13,7 @@ zenstore_forcelinktests()
 {
 	basicfile_forcelink();
 	CAS_forcelink();
+	filecas_forcelink();
 }
 
 }  // namespace zen