moved source directories into `/src` (#264)

* moved source directories into `/src`
* updated bundle.lua for new `src` path
* moved some docs, icon
* removed old test trees

1 files changed, 1312 insertions, 0 deletions

diff --git a/src/zenstore/blockstore.cpp b/src/zenstore/blockstore.cpp
new file mode 100644
index 000000000..5dfa10c91
--- /dev/null
+++ b/src/zenstore/blockstore.cpp
@@ -0,0 +1,1312 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenstore/blockstore.h>
+
+#include <zencore/fmtutils.h>
+#include <zencore/logging.h>
+#include <zencore/scopeguard.h>
+#include <zencore/timer.h>
+
+#include <algorithm>
+
+#if ZEN_WITH_TESTS
+#	include <zencore/compactbinarybuilder.h>
+#	include <zencore/testing.h>
+#	include <zencore/testutils.h>
+#	include <zencore/workthreadpool.h>
+#	include <random>
+#endif
+
+//////////////////////////////////////////////////////////////////////////
+
+namespace zen {
+
+//////////////////////////////////////////////////////////////////////////
+
+BlockStoreFile::BlockStoreFile(const std::filesystem::path& BlockPath) : m_Path(BlockPath)
+{
+}
+
+BlockStoreFile::~BlockStoreFile()
+{
+	m_IoBuffer = IoBuffer();
+	m_File.Detach();
+}
+
+const std::filesystem::path&
+BlockStoreFile::GetPath() const
+{
+	return m_Path;
+}
+
+void
+BlockStoreFile::Open()
+{
+	m_File.Open(m_Path, BasicFile::Mode::kDelete);
+	void* FileHandle = m_File.Handle();
+	m_IoBuffer		 = IoBuffer(IoBuffer::File, FileHandle, 0, m_File.FileSize());
+}
+
+void
+BlockStoreFile::Create(uint64_t InitialSize)
+{
+	auto ParentPath = m_Path.parent_path();
+	if (!std::filesystem::is_directory(ParentPath))
+	{
+		CreateDirectories(ParentPath);
+	}
+
+	m_File.Open(m_Path, BasicFile::Mode::kTruncateDelete);
+	void* FileHandle = m_File.Handle();
+
+	// We map our m_IoBuffer beyond the file size as we will grow it over time and want
+	// to be able to create sub-buffers of all the written range later
+	m_IoBuffer = IoBuffer(IoBuffer::File, FileHandle, 0, InitialSize);
+}
+
+uint64_t
+BlockStoreFile::FileSize()
+{
+	return m_File.FileSize();
+}
+
+void
+BlockStoreFile::MarkAsDeleteOnClose()
+{
+	m_IoBuffer.MarkAsDeleteOnClose();
+}
+
+IoBuffer
+BlockStoreFile::GetChunk(uint64_t Offset, uint64_t Size)
+{
+	return IoBuffer(m_IoBuffer, Offset, Size);
+}
+
+void
+BlockStoreFile::Read(void* Data, uint64_t Size, uint64_t FileOffset)
+{
+	m_File.Read(Data, Size, FileOffset);
+}
+
+void
+BlockStoreFile::Write(const void* Data, uint64_t Size, uint64_t FileOffset)
+{
+	m_File.Write(Data, Size, FileOffset);
+}
+
+void
+BlockStoreFile::Flush()
+{
+	m_File.Flush();
+}
+
+BasicFile&
+BlockStoreFile::GetBasicFile()
+{
+	return m_File;
+}
+
+void
+BlockStoreFile::StreamByteRange(uint64_t FileOffset, uint64_t Size, std::function<void(const void* Data, uint64_t Size)>&& ChunkFun)
+{
+	m_File.StreamByteRange(FileOffset, Size, std::move(ChunkFun));
+}
+
+constexpr uint64_t ScrubSmallChunkWindowSize = 4 * 1024 * 1024;
+
+void
+BlockStore::Initialize(const std::filesystem::path&			  BlocksBasePath,
+					   uint64_t								  MaxBlockSize,
+					   uint64_t								  MaxBlockCount,
+					   const std::vector<BlockStoreLocation>& KnownLocations)
+{
+	ZEN_ASSERT(MaxBlockSize > 0);
+	ZEN_ASSERT(MaxBlockCount > 0);
+	ZEN_ASSERT(IsPow2(MaxBlockCount));
+
+	m_TotalSize		 = 0;
+	m_BlocksBasePath = BlocksBasePath;
+	m_MaxBlockSize	 = MaxBlockSize;
+
+	m_ChunkBlocks.clear();
+
+	std::unordered_set<uint32_t> KnownBlocks;
+	for (const auto& Entry : KnownLocations)
+	{
+		KnownBlocks.insert(Entry.BlockIndex);
+	}
+
+	if (std::filesystem::is_directory(m_BlocksBasePath))
+	{
+		std::vector<std::filesystem::path> FoldersToScan;
+		FoldersToScan.push_back(m_BlocksBasePath);
+		size_t FolderOffset = 0;
+		while (FolderOffset < FoldersToScan.size())
+		{
+			for (const std::filesystem::directory_entry& Entry : std::filesystem::directory_iterator(FoldersToScan[FolderOffset]))
+			{
+				if (Entry.is_directory())
+				{
+					FoldersToScan.push_back(Entry.path());
+					continue;
+				}
+				if (Entry.is_regular_file())
+				{
+					const std::filesystem::path Path = Entry.path();
+					if (Path.extension() != GetBlockFileExtension())
+					{
+						continue;
+					}
+					std::string FileName = PathToUtf8(Path.stem());
+					uint32_t	BlockIndex;
+					bool		OK = ParseHexNumber(FileName, BlockIndex);
+					if (!OK)
+					{
+						continue;
+					}
+					if (!KnownBlocks.contains(BlockIndex))
+					{
+						// Log removing unreferenced block
+						// Clear out unused blocks
+						ZEN_DEBUG("removing unused block at '{}'", Path);
+						std::error_code Ec;
+						std::filesystem::remove(Path, Ec);
+						if (Ec)
+						{
+							ZEN_WARN("Failed to delete file '{}' reason: '{}'", Path, Ec.message());
+						}
+						continue;
+					}
+					Ref<BlockStoreFile> BlockFile{new BlockStoreFile(Path)};
+					BlockFile->Open();
+					m_TotalSize.fetch_add(BlockFile->FileSize(), std::memory_order::relaxed);
+					m_ChunkBlocks[BlockIndex] = BlockFile;
+				}
+			}
+			++FolderOffset;
+		}
+	}
+	else
+	{
+		CreateDirectories(m_BlocksBasePath);
+	}
+}
+
+void
+BlockStore::Close()
+{
+	RwLock::ExclusiveLockScope InsertLock(m_InsertLock);
+	m_WriteBlock		  = nullptr;
+	m_CurrentInsertOffset = 0;
+	m_WriteBlockIndex	  = 0;
+
+	m_ChunkBlocks.clear();
+	m_BlocksBasePath.clear();
+}
+
+void
+BlockStore::WriteChunk(const void* Data, uint64_t Size, uint64_t Alignment, const WriteChunkCallback& Callback)
+{
+	ZEN_ASSERT(Data != nullptr);
+	ZEN_ASSERT(Size > 0u);
+	ZEN_ASSERT(Size <= m_MaxBlockSize);
+	ZEN_ASSERT(Alignment > 0u);
+
+	RwLock::ExclusiveLockScope InsertLock(m_InsertLock);
+
+	uint32_t WriteBlockIndex = m_WriteBlockIndex.load(std::memory_order_acquire);
+	bool	 IsWriting		 = !!m_WriteBlock;
+	if (!IsWriting || (m_CurrentInsertOffset + Size) > m_MaxBlockSize)
+	{
+		if (m_WriteBlock)
+		{
+			m_WriteBlock = nullptr;
+		}
+
+		if (m_ChunkBlocks.size() == m_MaxBlockCount)
+		{
+			throw std::runtime_error(fmt::format("unable to allocate a new block in '{}'", m_BlocksBasePath));
+		}
+
+		WriteBlockIndex += IsWriting ? 1 : 0;
+		while (m_ChunkBlocks.contains(WriteBlockIndex))
+		{
+			WriteBlockIndex = (WriteBlockIndex + 1) & (m_MaxBlockCount - 1);
+		}
+
+		std::filesystem::path BlockPath = GetBlockPath(m_BlocksBasePath, WriteBlockIndex);
+
+		Ref<BlockStoreFile> NewBlockFile(new BlockStoreFile(BlockPath));
+		NewBlockFile->Create(m_MaxBlockSize);
+
+		m_ChunkBlocks[WriteBlockIndex] = NewBlockFile;
+		m_WriteBlock				   = NewBlockFile;
+		m_WriteBlockIndex.store(WriteBlockIndex, std::memory_order_release);
+		m_CurrentInsertOffset = 0;
+	}
+	uint64_t InsertOffset				 = m_CurrentInsertOffset;
+	m_CurrentInsertOffset				 = RoundUp(InsertOffset + Size, Alignment);
+	uint64_t			AlignedWriteSize = m_CurrentInsertOffset - InsertOffset;
+	Ref<BlockStoreFile> WriteBlock		 = m_WriteBlock;
+	m_ActiveWriteBlocks.push_back(WriteBlockIndex);
+	InsertLock.ReleaseNow();
+
+	WriteBlock->Write(Data, Size, InsertOffset);
+	m_TotalSize.fetch_add(AlignedWriteSize, std::memory_order::relaxed);
+
+	Callback({.BlockIndex = WriteBlockIndex, .Offset = InsertOffset, .Size = Size});
+
+	{
+		RwLock::ExclusiveLockScope _(m_InsertLock);
+		m_ActiveWriteBlocks.erase(std::find(m_ActiveWriteBlocks.begin(), m_ActiveWriteBlocks.end(), WriteBlockIndex));
+	}
+}
+
+BlockStore::ReclaimSnapshotState
+BlockStore::GetReclaimSnapshotState()
+{
+	ReclaimSnapshotState	State;
+	RwLock::SharedLockScope _(m_InsertLock);
+	for (uint32_t BlockIndex : m_ActiveWriteBlocks)
+	{
+		State.m_ActiveWriteBlocks.insert(BlockIndex);
+	}
+	if (m_WriteBlock)
+	{
+		State.m_ActiveWriteBlocks.insert(m_WriteBlockIndex);
+	}
+	State.BlockCount = m_ChunkBlocks.size();
+	return State;
+}
+
+IoBuffer
+BlockStore::TryGetChunk(const BlockStoreLocation& Location) const
+{
+	RwLock::SharedLockScope InsertLock(m_InsertLock);
+	if (auto BlockIt = m_ChunkBlocks.find(Location.BlockIndex); BlockIt != m_ChunkBlocks.end())
+	{
+		if (const Ref<BlockStoreFile>& Block = BlockIt->second; Block)
+		{
+			return Block->GetChunk(Location.Offset, Location.Size);
+		}
+	}
+	return IoBuffer();
+}
+
+void
+BlockStore::Flush()
+{
+	RwLock::ExclusiveLockScope _(m_InsertLock);
+	if (m_CurrentInsertOffset > 0)
+	{
+		uint32_t WriteBlockIndex = m_WriteBlockIndex.load(std::memory_order_acquire);
+		WriteBlockIndex			 = (WriteBlockIndex + 1) & (m_MaxBlockCount - 1);
+		m_WriteBlock			 = nullptr;
+		m_WriteBlockIndex.store(WriteBlockIndex, std::memory_order_release);
+		m_CurrentInsertOffset = 0;
+	}
+}
+
+void
+BlockStore::ReclaimSpace(const ReclaimSnapshotState&			Snapshot,
+						 const std::vector<BlockStoreLocation>& ChunkLocations,
+						 const ChunkIndexArray&					KeepChunkIndexes,
+						 uint64_t								PayloadAlignment,
+						 bool									DryRun,
+						 const ReclaimCallback&					ChangeCallback,
+						 const ClaimDiskReserveCallback&		DiskReserveCallback)
+{
+	if (ChunkLocations.empty())
+	{
+		return;
+	}
+	uint64_t WriteBlockTimeUs		 = 0;
+	uint64_t WriteBlockLongestTimeUs = 0;
+	uint64_t ReadBlockTimeUs		 = 0;
+	uint64_t ReadBlockLongestTimeUs	 = 0;
+	uint64_t TotalChunkCount		 = ChunkLocations.size();
+	uint64_t DeletedSize			 = 0;
+	uint64_t OldTotalSize			 = 0;
+	uint64_t NewTotalSize			 = 0;
+
+	uint64_t MovedCount	  = 0;
+	uint64_t DeletedCount = 0;
+
+	Stopwatch  TotalTimer;
+	const auto _ = MakeGuard([&] {
+		ZEN_DEBUG(
+			"reclaim space for '{}' DONE after {}, write lock: {} ({}), read lock: {} ({}), collected {} bytes, deleted {} and moved "
+			"{} "
+			"of {} "
+			"chunks ({}).",
+			m_BlocksBasePath,
+			NiceTimeSpanMs(TotalTimer.GetElapsedTimeMs()),
+			NiceLatencyNs(WriteBlockTimeUs),
+			NiceLatencyNs(WriteBlockLongestTimeUs),
+			NiceLatencyNs(ReadBlockTimeUs),
+			NiceLatencyNs(ReadBlockLongestTimeUs),
+			NiceBytes(DeletedSize),
+			DeletedCount,
+			MovedCount,
+			TotalChunkCount,
+			NiceBytes(OldTotalSize));
+	});
+
+	size_t BlockCount = Snapshot.BlockCount;
+	if (BlockCount == 0)
+	{
+		ZEN_DEBUG("garbage collect for '{}' SKIPPED, no blocks to process", m_BlocksBasePath);
+		return;
+	}
+
+	std::unordered_set<size_t> KeepChunkMap;
+	KeepChunkMap.reserve(KeepChunkIndexes.size());
+	for (size_t KeepChunkIndex : KeepChunkIndexes)
+	{
+		KeepChunkMap.insert(KeepChunkIndex);
+	}
+
+	std::unordered_map<uint32_t, size_t> BlockIndexToChunkMapIndex;
+	std::vector<ChunkIndexArray>		 BlockKeepChunks;
+	std::vector<ChunkIndexArray>		 BlockDeleteChunks;
+
+	BlockIndexToChunkMapIndex.reserve(BlockCount);
+	BlockKeepChunks.reserve(BlockCount);
+	BlockDeleteChunks.reserve(BlockCount);
+	size_t GuesstimateCountPerBlock = TotalChunkCount / BlockCount / 2;
+
+	size_t DeleteCount = 0;
+	for (size_t Index = 0; Index < TotalChunkCount; ++Index)
+	{
+		const BlockStoreLocation& Location = ChunkLocations[Index];
+		OldTotalSize += Location.Size;
+		if (Snapshot.m_ActiveWriteBlocks.contains(Location.BlockIndex))
+		{
+			continue;
+		}
+
+		auto   BlockIndexPtr = BlockIndexToChunkMapIndex.find(Location.BlockIndex);
+		size_t ChunkMapIndex = 0;
+		if (BlockIndexPtr == BlockIndexToChunkMapIndex.end())
+		{
+			ChunkMapIndex								   = BlockKeepChunks.size();
+			BlockIndexToChunkMapIndex[Location.BlockIndex] = ChunkMapIndex;
+			BlockKeepChunks.resize(ChunkMapIndex + 1);
+			BlockKeepChunks.back().reserve(GuesstimateCountPerBlock);
+			BlockDeleteChunks.resize(ChunkMapIndex + 1);
+			BlockDeleteChunks.back().reserve(GuesstimateCountPerBlock);
+		}
+		else
+		{
+			ChunkMapIndex = BlockIndexPtr->second;
+		}
+
+		if (KeepChunkMap.contains(Index))
+		{
+			ChunkIndexArray& IndexMap = BlockKeepChunks[ChunkMapIndex];
+			IndexMap.push_back(Index);
+			NewTotalSize += Location.Size;
+			continue;
+		}
+		ChunkIndexArray& IndexMap = BlockDeleteChunks[ChunkMapIndex];
+		IndexMap.push_back(Index);
+		DeleteCount++;
+	}
+
+	std::unordered_set<uint32_t> BlocksToReWrite;
+	BlocksToReWrite.reserve(BlockIndexToChunkMapIndex.size());
+	for (const auto& Entry : BlockIndexToChunkMapIndex)
+	{
+		uint32_t			   BlockIndex	 = Entry.first;
+		size_t				   ChunkMapIndex = Entry.second;
+		const ChunkIndexArray& ChunkMap		 = BlockDeleteChunks[ChunkMapIndex];
+		if (ChunkMap.empty())
+		{
+			continue;
+		}
+		BlocksToReWrite.insert(BlockIndex);
+	}
+
+	if (DryRun)
+	{
+		ZEN_DEBUG("garbage collect for '{}' DISABLED, found {} {} chunks of total {} {}",
+				  m_BlocksBasePath,
+				  DeleteCount,
+				  NiceBytes(OldTotalSize - NewTotalSize),
+				  TotalChunkCount,
+				  OldTotalSize);
+		return;
+	}
+
+	Ref<BlockStoreFile> NewBlockFile;
+	try
+	{
+		uint64_t WriteOffset   = 0;
+		uint32_t NewBlockIndex = 0;
+		for (uint32_t BlockIndex : BlocksToReWrite)
+		{
+			const size_t ChunkMapIndex = BlockIndexToChunkMapIndex[BlockIndex];
+
+			Ref<BlockStoreFile> OldBlockFile;
+			{
+				RwLock::SharedLockScope _i(m_InsertLock);
+				Stopwatch				Timer;
+				const auto				__ = MakeGuard([&] {
+					 uint64_t ElapsedUs = Timer.GetElapsedTimeUs();
+					 WriteBlockTimeUs += ElapsedUs;
+					 WriteBlockLongestTimeUs = std::max(ElapsedUs, WriteBlockLongestTimeUs);
+				 });
+				OldBlockFile			   = m_ChunkBlocks[BlockIndex];
+			}
+
+			if (!OldBlockFile)
+			{
+				// If the block file pointed to does not exist, move them all to deleted list
+				BlockDeleteChunks[ChunkMapIndex].insert(BlockDeleteChunks[ChunkMapIndex].end(),
+														BlockKeepChunks[ChunkMapIndex].begin(),
+														BlockKeepChunks[ChunkMapIndex].end());
+				BlockKeepChunks[ChunkMapIndex].clear();
+			}
+
+			const ChunkIndexArray& KeepMap = BlockKeepChunks[ChunkMapIndex];
+			if (KeepMap.empty())
+			{
+				const ChunkIndexArray& DeleteMap = BlockDeleteChunks[ChunkMapIndex];
+				for (size_t DeleteIndex : DeleteMap)
+				{
+					DeletedSize += ChunkLocations[DeleteIndex].Size;
+				}
+				ChangeCallback({}, DeleteMap);
+				DeletedCount += DeleteMap.size();
+				{
+					RwLock::ExclusiveLockScope _i(m_InsertLock);
+					Stopwatch				   Timer;
+					const auto				   __ = MakeGuard([&] {
+						uint64_t ElapsedUs = Timer.GetElapsedTimeUs();
+						ReadBlockTimeUs += ElapsedUs;
+						ReadBlockLongestTimeUs = std::max(ElapsedUs, ReadBlockLongestTimeUs);
+					});
+					if (OldBlockFile)
+					{
+						m_ChunkBlocks[BlockIndex] = nullptr;
+						ZEN_DEBUG("marking cas block store file '{}' for delete, block #{}", OldBlockFile->GetPath(), BlockIndex);
+						m_TotalSize.fetch_sub(OldBlockFile->FileSize(), std::memory_order::relaxed);
+						OldBlockFile->MarkAsDeleteOnClose();
+					}
+				}
+				continue;
+			}
+
+			ZEN_ASSERT(OldBlockFile);
+
+			MovedChunksArray	 MovedChunks;
+			std::vector<uint8_t> Chunk;
+			for (const size_t& ChunkIndex : KeepMap)
+			{
+				const BlockStoreLocation ChunkLocation = ChunkLocations[ChunkIndex];
+				Chunk.resize(ChunkLocation.Size);
+				OldBlockFile->Read(Chunk.data(), Chunk.size(), ChunkLocation.Offset);
+
+				if (!NewBlockFile || (WriteOffset + Chunk.size() > m_MaxBlockSize))
+				{
+					uint32_t NextBlockIndex = m_WriteBlockIndex.load(std::memory_order_relaxed);
+
+					if (NewBlockFile)
+					{
+						NewBlockFile->Flush();
+						NewBlockFile = nullptr;
+					}
+					{
+						ChangeCallback(MovedChunks, {});
+						MovedCount += KeepMap.size();
+						MovedChunks.clear();
+						RwLock::ExclusiveLockScope __(m_InsertLock);
+						Stopwatch				   Timer;
+						const auto				   ___ = MakeGuard([&] {
+							uint64_t ElapsedUs = Timer.GetElapsedTimeUs();
+							ReadBlockTimeUs += ElapsedUs;
+							ReadBlockLongestTimeUs = std::max(ElapsedUs, ReadBlockLongestTimeUs);
+						});
+						if (m_ChunkBlocks.size() == m_MaxBlockCount)
+						{
+							ZEN_ERROR("unable to allocate a new block in '{}', count limit {} exeeded",
+									  m_BlocksBasePath,
+									  static_cast<uint64_t>(std::numeric_limits<uint32_t>::max()) + 1);
+							return;
+						}
+						while (m_ChunkBlocks.contains(NextBlockIndex))
+						{
+							NextBlockIndex = (NextBlockIndex + 1) & (m_MaxBlockCount - 1);
+						}
+						std::filesystem::path NewBlockPath = GetBlockPath(m_BlocksBasePath, NextBlockIndex);
+						NewBlockFile					   = new BlockStoreFile(NewBlockPath);
+						m_ChunkBlocks[NextBlockIndex]	   = NewBlockFile;
+					}
+
+					std::error_code Error;
+					DiskSpace		Space = DiskSpaceInfo(m_BlocksBasePath, Error);
+					if (Error)
+					{
+						ZEN_ERROR("get disk space in '{}' FAILED, reason: '{}'", m_BlocksBasePath, Error.message());
+						return;
+					}
+					if (Space.Free < m_MaxBlockSize)
+					{
+						uint64_t ReclaimedSpace = DiskReserveCallback();
+						if (Space.Free + ReclaimedSpace < m_MaxBlockSize)
+						{
+							ZEN_WARN("garbage collect for '{}' FAILED, required disk space {}, free {}",
+									 m_BlocksBasePath,
+									 m_MaxBlockSize,
+									 NiceBytes(Space.Free + ReclaimedSpace));
+							RwLock::ExclusiveLockScope _l(m_InsertLock);
+							Stopwatch				   Timer;
+							const auto				   __ = MakeGuard([&] {
+								uint64_t ElapsedUs = Timer.GetElapsedTimeUs();
+								ReadBlockTimeUs += ElapsedUs;
+								ReadBlockLongestTimeUs = std::max(ElapsedUs, ReadBlockLongestTimeUs);
+							});
+							m_ChunkBlocks.erase(NextBlockIndex);
+							return;
+						}
+
+						ZEN_INFO("using gc reserve for '{}', reclaimed {}, disk free {}",
+								 m_BlocksBasePath,
+								 ReclaimedSpace,
+								 NiceBytes(Space.Free + ReclaimedSpace));
+					}
+					NewBlockFile->Create(m_MaxBlockSize);
+					NewBlockIndex = NextBlockIndex;
+					WriteOffset	  = 0;
+				}
+
+				NewBlockFile->Write(Chunk.data(), Chunk.size(), WriteOffset);
+				MovedChunks.push_back({ChunkIndex, {.BlockIndex = NewBlockIndex, .Offset = WriteOffset, .Size = Chunk.size()}});
+				uint64_t OldOffset = WriteOffset;
+				WriteOffset		   = RoundUp(WriteOffset + Chunk.size(), PayloadAlignment);
+				m_TotalSize.fetch_add(WriteOffset - OldOffset, std::memory_order::relaxed);
+			}
+			Chunk.clear();
+			if (NewBlockFile)
+			{
+				NewBlockFile->Flush();
+				NewBlockFile = nullptr;
+			}
+
+			const ChunkIndexArray& DeleteMap = BlockDeleteChunks[ChunkMapIndex];
+			for (size_t DeleteIndex : DeleteMap)
+			{
+				DeletedSize += ChunkLocations[DeleteIndex].Size;
+			}
+
+			ChangeCallback(MovedChunks, DeleteMap);
+			MovedCount += KeepMap.size();
+			DeletedCount += DeleteMap.size();
+			MovedChunks.clear();
+			{
+				RwLock::ExclusiveLockScope __(m_InsertLock);
+				Stopwatch				   Timer;
+				const auto				   ___ = MakeGuard([&] {
+					uint64_t ElapsedUs = Timer.GetElapsedTimeUs();
+					ReadBlockTimeUs += ElapsedUs;
+					ReadBlockLongestTimeUs = std::max(ElapsedUs, ReadBlockLongestTimeUs);
+				});
+				m_ChunkBlocks[BlockIndex]	   = nullptr;
+				ZEN_DEBUG("marking cas block store file '{}' for delete, block #{}", OldBlockFile->GetPath(), BlockIndex);
+				m_TotalSize.fetch_sub(OldBlockFile->FileSize(), std::memory_order::relaxed);
+				OldBlockFile->MarkAsDeleteOnClose();
+			}
+		}
+	}
+	catch (std::exception& ex)
+	{
+		ZEN_ERROR("reclaiming space for '{}' failed with: '{}'", m_BlocksBasePath, ex.what());
+		if (NewBlockFile)
+		{
+			ZEN_DEBUG("dropping incomplete cas block store file '{}'", NewBlockFile->GetPath());
+			m_TotalSize.fetch_sub(NewBlockFile->FileSize(), std::memory_order::relaxed);
+			NewBlockFile->MarkAsDeleteOnClose();
+		}
+	}
+}
+
+void
+BlockStore::IterateChunks(const std::vector<BlockStoreLocation>& ChunkLocations,
+						  const IterateChunksSmallSizeCallback&	 SmallSizeCallback,
+						  const IterateChunksLargeSizeCallback&	 LargeSizeCallback)
+{
+	std::vector<size_t> LocationIndexes;
+	LocationIndexes.reserve(ChunkLocations.size());
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkLocations.size(); ++ChunkIndex)
+	{
+		LocationIndexes.push_back(ChunkIndex);
+	}
+	std::sort(LocationIndexes.begin(), LocationIndexes.end(), [&](size_t IndexA, size_t IndexB) -> bool {
+		const BlockStoreLocation& LocationA = ChunkLocations[IndexA];
+		const BlockStoreLocation& LocationB = ChunkLocations[IndexB];
+		if (LocationA.BlockIndex < LocationB.BlockIndex)
+		{
+			return true;
+		}
+		else if (LocationA.BlockIndex > LocationB.BlockIndex)
+		{
+			return false;
+		}
+		return LocationA.Offset < LocationB.Offset;
+	});
+
+	IoBuffer ReadBuffer{ScrubSmallChunkWindowSize};
+	void*	 BufferBase = ReadBuffer.MutableData();
+
+	RwLock::SharedLockScope _(m_InsertLock);
+
+	auto GetNextRange = [&](size_t StartIndexOffset) {
+		size_t					  ChunkCount	= 0;
+		size_t					  StartIndex	= LocationIndexes[StartIndexOffset];
+		const BlockStoreLocation& StartLocation = ChunkLocations[StartIndex];
+		uint64_t				  StartOffset	= StartLocation.Offset;
+		while (StartIndexOffset + ChunkCount < LocationIndexes.size())
+		{
+			size_t					  NextIndex = LocationIndexes[StartIndexOffset + ChunkCount];
+			const BlockStoreLocation& Location	= ChunkLocations[NextIndex];
+			if (Location.BlockIndex != StartLocation.BlockIndex)
+			{
+				break;
+			}
+			if ((Location.Offset + Location.Size) - StartOffset > ScrubSmallChunkWindowSize)
+			{
+				break;
+			}
+			++ChunkCount;
+		}
+		return ChunkCount;
+	};
+
+	size_t LocationIndexOffset = 0;
+	while (LocationIndexOffset < LocationIndexes.size())
+	{
+		size_t					  ChunkIndex	= LocationIndexes[LocationIndexOffset];
+		const BlockStoreLocation& FirstLocation = ChunkLocations[ChunkIndex];
+
+		const Ref<BlockStoreFile>& BlockFile = m_ChunkBlocks[FirstLocation.BlockIndex];
+		if (!BlockFile)
+		{
+			while (ChunkLocations[ChunkIndex].BlockIndex == FirstLocation.BlockIndex)
+			{
+				SmallSizeCallback(ChunkIndex, nullptr, 0);
+				LocationIndexOffset++;
+				if (LocationIndexOffset == LocationIndexes.size())
+				{
+					break;
+				}
+				ChunkIndex = LocationIndexes[LocationIndexOffset];
+			}
+			continue;
+		}
+		size_t BlockSize  = BlockFile->FileSize();
+		size_t RangeCount = GetNextRange(LocationIndexOffset);
+		if (RangeCount > 0)
+		{
+			size_t					  LastChunkIndex = LocationIndexes[LocationIndexOffset + RangeCount - 1];
+			const BlockStoreLocation& LastLocation	 = ChunkLocations[LastChunkIndex];
+			uint64_t				  Size			 = LastLocation.Offset + LastLocation.Size - FirstLocation.Offset;
+			BlockFile->Read(BufferBase, Size, FirstLocation.Offset);
+			for (size_t RangeIndex = 0; RangeIndex < RangeCount; ++RangeIndex)
+			{
+				size_t					  NextChunkIndex = LocationIndexes[LocationIndexOffset + RangeIndex];
+				const BlockStoreLocation& ChunkLocation	 = ChunkLocations[NextChunkIndex];
+				if (ChunkLocation.Size == 0 || (ChunkLocation.Offset + ChunkLocation.Size > BlockSize))
+				{
+					SmallSizeCallback(NextChunkIndex, nullptr, 0);
+					continue;
+				}
+				void* BufferPtr = &((char*)BufferBase)[ChunkLocation.Offset - FirstLocation.Offset];
+				SmallSizeCallback(NextChunkIndex, BufferPtr, ChunkLocation.Size);
+			}
+			LocationIndexOffset += RangeCount;
+			continue;
+		}
+		if (FirstLocation.Size == 0 || (FirstLocation.Offset + FirstLocation.Size > BlockSize))
+		{
+			SmallSizeCallback(ChunkIndex, nullptr, 0);
+			LocationIndexOffset++;
+			continue;
+		}
+		LargeSizeCallback(ChunkIndex, *BlockFile.Get(), FirstLocation.Offset, FirstLocation.Size);
+		LocationIndexOffset++;
+	}
+}
+
+const char*
+BlockStore::GetBlockFileExtension()
+{
+	return ".ucas";
+}
+
+std::filesystem::path
+BlockStore::GetBlockPath(const std::filesystem::path& BlocksBasePath, const uint32_t BlockIndex)
+{
+	ExtendablePathBuilder<256> Path;
+
+	char BlockHexString[9];
+	ToHexNumber(BlockIndex, BlockHexString);
+
+	Path.Append(BlocksBasePath);
+	Path.AppendSeparator();
+	Path.AppendAsciiRange(BlockHexString, BlockHexString + 4);
+	Path.AppendSeparator();
+	Path.Append(BlockHexString);
+	Path.Append(GetBlockFileExtension());
+	return Path.ToPath();
+}
+
+#if ZEN_WITH_TESTS
+
+TEST_CASE("blockstore.blockstoredisklocation")
+{
+	BlockStoreLocation Zero = BlockStoreLocation{.BlockIndex = 0, .Offset = 0, .Size = 0};
+	CHECK(Zero == BlockStoreDiskLocation(Zero, 4).Get(4));
+
+	BlockStoreLocation MaxBlockIndex = BlockStoreLocation{.BlockIndex = BlockStoreDiskLocation::MaxBlockIndex, .Offset = 0, .Size = 0};
+	CHECK(MaxBlockIndex == BlockStoreDiskLocation(MaxBlockIndex, 4).Get(4));
+
+	BlockStoreLocation MaxOffset = BlockStoreLocation{.BlockIndex = 0, .Offset = BlockStoreDiskLocation::MaxOffset * 4, .Size = 0};
+	CHECK(MaxOffset == BlockStoreDiskLocation(MaxOffset, 4).Get(4));
+
+	BlockStoreLocation MaxSize = BlockStoreLocation{.BlockIndex = 0, .Offset = 0, .Size = std::numeric_limits<uint32_t>::max()};
+	CHECK(MaxSize == BlockStoreDiskLocation(MaxSize, 4).Get(4));
+
+	BlockStoreLocation MaxBlockIndexAndOffset =
+		BlockStoreLocation{.BlockIndex = BlockStoreDiskLocation::MaxBlockIndex, .Offset = BlockStoreDiskLocation::MaxOffset * 4, .Size = 0};
+	CHECK(MaxBlockIndexAndOffset == BlockStoreDiskLocation(MaxBlockIndexAndOffset, 4).Get(4));
+
+	BlockStoreLocation MaxAll = BlockStoreLocation{.BlockIndex = BlockStoreDiskLocation::MaxBlockIndex,
+												   .Offset	   = BlockStoreDiskLocation::MaxOffset * 4,
+												   .Size	   = std::numeric_limits<uint32_t>::max()};
+	CHECK(MaxAll == BlockStoreDiskLocation(MaxAll, 4).Get(4));
+
+	BlockStoreLocation MaxAll4096 = BlockStoreLocation{.BlockIndex = BlockStoreDiskLocation::MaxBlockIndex,
+													   .Offset	   = BlockStoreDiskLocation::MaxOffset * 4096,
+													   .Size	   = std::numeric_limits<uint32_t>::max()};
+	CHECK(MaxAll4096 == BlockStoreDiskLocation(MaxAll4096, 4096).Get(4096));
+
+	BlockStoreLocation Middle = BlockStoreLocation{.BlockIndex = (BlockStoreDiskLocation::MaxBlockIndex) / 2,
+												   .Offset	   = ((BlockStoreDiskLocation::MaxOffset) / 2) * 4,
+												   .Size	   = std::numeric_limits<uint32_t>::max() / 2};
+	CHECK(Middle == BlockStoreDiskLocation(Middle, 4).Get(4));
+}
+
+TEST_CASE("blockstore.blockfile")
+{
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path() / "blocks";
+	CreateDirectories(RootDirectory);
+
+	{
+		BlockStoreFile File1(RootDirectory / "1");
+		File1.Create(16384);
+		CHECK(File1.FileSize() == 0);
+		File1.Write("data", 5, 0);
+		IoBuffer DataChunk = File1.GetChunk(0, 5);
+		File1.Write("boop", 5, 5);
+		IoBuffer	BoopChunk = File1.GetChunk(5, 5);
+		const char* Data	  = static_cast<const char*>(DataChunk.GetData());
+		CHECK(std::string(Data) == "data");
+		const char* Boop = static_cast<const char*>(BoopChunk.GetData());
+		CHECK(std::string(Boop) == "boop");
+		File1.Flush();
+		CHECK(File1.FileSize() == 10);
+	}
+	{
+		BlockStoreFile File1(RootDirectory / "1");
+		File1.Open();
+
+		char DataRaw[5];
+		File1.Read(DataRaw, 5, 0);
+		CHECK(std::string(DataRaw) == "data");
+		IoBuffer DataChunk = File1.GetChunk(0, 5);
+
+		char BoopRaw[5];
+		File1.Read(BoopRaw, 5, 5);
+		CHECK(std::string(BoopRaw) == "boop");
+
+		IoBuffer	BoopChunk = File1.GetChunk(5, 5);
+		const char* Data	  = static_cast<const char*>(DataChunk.GetData());
+		CHECK(std::string(Data) == "data");
+		const char* Boop = static_cast<const char*>(BoopChunk.GetData());
+		CHECK(std::string(Boop) == "boop");
+	}
+
+	{
+		IoBuffer DataChunk;
+		IoBuffer BoopChunk;
+
+		{
+			BlockStoreFile File1(RootDirectory / "1");
+			File1.Open();
+			DataChunk = File1.GetChunk(0, 5);
+			BoopChunk = File1.GetChunk(5, 5);
+		}
+
+		CHECK(std::filesystem::exists(RootDirectory / "1"));
+
+		const char* Data = static_cast<const char*>(DataChunk.GetData());
+		CHECK(std::string(Data) == "data");
+		const char* Boop = static_cast<const char*>(BoopChunk.GetData());
+		CHECK(std::string(Boop) == "boop");
+	}
+	CHECK(std::filesystem::exists(RootDirectory / "1"));
+
+	{
+		IoBuffer DataChunk;
+		IoBuffer BoopChunk;
+
+		{
+			BlockStoreFile File1(RootDirectory / "1");
+			File1.Open();
+			File1.MarkAsDeleteOnClose();
+			DataChunk = File1.GetChunk(0, 5);
+			BoopChunk = File1.GetChunk(5, 5);
+		}
+
+		const char* Data = static_cast<const char*>(DataChunk.GetData());
+		CHECK(std::string(Data) == "data");
+		const char* Boop = static_cast<const char*>(BoopChunk.GetData());
+		CHECK(std::string(Boop) == "boop");
+	}
+	CHECK(!std::filesystem::exists(RootDirectory / "1"));
+}
+
+namespace blockstore::impl {
+	BlockStoreLocation WriteStringAsChunk(BlockStore& Store, std::string_view String, size_t PayloadAlignment)
+	{
+		BlockStoreLocation Location;
+		Store.WriteChunk(String.data(), String.length(), PayloadAlignment, [&](const BlockStoreLocation& L) { Location = L; });
+		CHECK(Location.Size == String.length());
+		return Location;
+	};
+
+	std::string ReadChunkAsString(BlockStore& Store, const BlockStoreLocation& Location)
+	{
+		IoBuffer ChunkData = Store.TryGetChunk(Location);
+		if (!ChunkData)
+		{
+			return "";
+		}
+		std::string AsString((const char*)ChunkData.Data(), ChunkData.Size());
+		return AsString;
+	};
+
+	std::vector<std::filesystem::path> GetDirectoryContent(std::filesystem::path RootDir, bool Files, bool Directories)
+	{
+		DirectoryContent DirectoryContent;
+		GetDirectoryContent(RootDir,
+							DirectoryContent::RecursiveFlag | (Files ? DirectoryContent::IncludeFilesFlag : 0) |
+								(Directories ? DirectoryContent::IncludeDirsFlag : 0),
+							DirectoryContent);
+		std::vector<std::filesystem::path> Result;
+		Result.insert(Result.end(), DirectoryContent.Directories.begin(), DirectoryContent.Directories.end());
+		Result.insert(Result.end(), DirectoryContent.Files.begin(), DirectoryContent.Files.end());
+		return Result;
+	};
+
+	static IoBuffer CreateChunk(uint64_t Size)
+	{
+		static std::random_device rd;
+		static std::mt19937		  g(rd());
+
+		std::vector<uint8_t> Values;
+		Values.resize(Size);
+		for (size_t Idx = 0; Idx < Size; ++Idx)
+		{
+			Values[Idx] = static_cast<uint8_t>(Idx);
+		}
+		std::shuffle(Values.begin(), Values.end(), g);
+
+		return IoBufferBuilder::MakeCloneFromMemory(Values.data(), Values.size());
+	}
+}  // namespace blockstore::impl
+
+TEST_CASE("blockstore.chunks")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory, 128, 1024, {});
+	IoBuffer BadChunk = Store.TryGetChunk({.BlockIndex = 0, .Offset = 0, .Size = 512});
+	CHECK(!BadChunk);
+
+	std::string		   FirstChunkData	   = "This is the data of the first chunk that we will write";
+	BlockStoreLocation FirstChunkLocation  = WriteStringAsChunk(Store, FirstChunkData, 4);
+	std::string		   SecondChunkData	   = "This is the data for the second chunk that we will write";
+	BlockStoreLocation SecondChunkLocation = WriteStringAsChunk(Store, SecondChunkData, 4);
+
+	CHECK(ReadChunkAsString(Store, FirstChunkLocation) == FirstChunkData);
+	CHECK(ReadChunkAsString(Store, SecondChunkLocation) == SecondChunkData);
+
+	std::string ThirdChunkData =
+		"This is a much longer string that will not fit in the first block so it should be placed in the second block";
+	BlockStoreLocation ThirdChunkLocation = WriteStringAsChunk(Store, ThirdChunkData, 4);
+	CHECK(ThirdChunkLocation.BlockIndex != FirstChunkLocation.BlockIndex);
+
+	CHECK(ReadChunkAsString(Store, FirstChunkLocation) == FirstChunkData);
+	CHECK(ReadChunkAsString(Store, SecondChunkLocation) == SecondChunkData);
+	CHECK(ReadChunkAsString(Store, ThirdChunkLocation) == ThirdChunkData);
+}
+
+TEST_CASE("blockstore.clean.stray.blocks")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory / "store", 128, 1024, {});
+
+	std::string		   FirstChunkData	   = "This is the data of the first chunk that we will write";
+	BlockStoreLocation FirstChunkLocation  = WriteStringAsChunk(Store, FirstChunkData, 4);
+	std::string		   SecondChunkData	   = "This is the data for the second chunk that we will write";
+	BlockStoreLocation SecondChunkLocation = WriteStringAsChunk(Store, SecondChunkData, 4);
+	std::string		   ThirdChunkData =
+		"This is a much longer string that will not fit in the first block so it should be placed in the second block";
+	WriteStringAsChunk(Store, ThirdChunkData, 4);
+
+	Store.Close();
+
+	// Not referencing the second block means that we should be deleted
+	Store.Initialize(RootDirectory / "store", 128, 1024, {FirstChunkLocation, SecondChunkLocation});
+
+	CHECK(GetDirectoryContent(RootDirectory / "store", true, false).size() == 1);
+}
+
+TEST_CASE("blockstore.flush.forces.new.block")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory / "store", 128, 1024, {});
+
+	std::string FirstChunkData = "This is the data of the first chunk that we will write";
+	WriteStringAsChunk(Store, FirstChunkData, 4);
+	Store.Flush();
+	std::string SecondChunkData = "This is the data for the second chunk that we will write";
+	WriteStringAsChunk(Store, SecondChunkData, 4);
+	Store.Flush();
+	std::string ThirdChunkData =
+		"This is a much longer string that will not fit in the first block so it should be placed in the second block";
+	WriteStringAsChunk(Store, ThirdChunkData, 4);
+
+	CHECK(GetDirectoryContent(RootDirectory / "store", true, false).size() == 3);
+}
+
+TEST_CASE("blockstore.iterate.chunks")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory / "store", ScrubSmallChunkWindowSize * 2, 1024, {});
+	IoBuffer BadChunk = Store.TryGetChunk({.BlockIndex = 0, .Offset = 0, .Size = 512});
+	CHECK(!BadChunk);
+
+	std::string		   FirstChunkData	  = "This is the data of the first chunk that we will write";
+	BlockStoreLocation FirstChunkLocation = WriteStringAsChunk(Store, FirstChunkData, 4);
+
+	std::string		   SecondChunkData	   = "This is the data for the second chunk that we will write";
+	BlockStoreLocation SecondChunkLocation = WriteStringAsChunk(Store, SecondChunkData, 4);
+	Store.Flush();
+
+	std::string		   VeryLargeChunk(ScrubSmallChunkWindowSize * 2, 'L');
+	BlockStoreLocation VeryLargeChunkLocation = WriteStringAsChunk(Store, VeryLargeChunk, 4);
+
+	BlockStoreLocation BadLocationZeroSize	 = {.BlockIndex = 0, .Offset = 0, .Size = 0};
+	BlockStoreLocation BadLocationOutOfRange = {.BlockIndex = 0,
+												.Offset		= ScrubSmallChunkWindowSize,
+												.Size		= ScrubSmallChunkWindowSize * 2};
+	BlockStoreLocation BadBlockIndex		 = {.BlockIndex = 0xfffff, .Offset = 1024, .Size = 1024};
+
+	Store.IterateChunks(
+		{FirstChunkLocation, SecondChunkLocation, VeryLargeChunkLocation, BadLocationZeroSize, BadLocationOutOfRange, BadBlockIndex},
+		[&](size_t ChunkIndex, const void* Data, uint64_t Size) {
+			switch (ChunkIndex)
+			{
+				case 0:
+					CHECK(Data);
+					CHECK(Size == FirstChunkData.size());
+					CHECK(std::string((const char*)Data, Size) == FirstChunkData);
+					break;
+				case 1:
+					CHECK(Data);
+					CHECK(Size == SecondChunkData.size());
+					CHECK(std::string((const char*)Data, Size) == SecondChunkData);
+					break;
+				case 2:
+					CHECK(false);
+					break;
+				case 3:
+					CHECK(!Data);
+					break;
+				case 4:
+					CHECK(!Data);
+					break;
+				case 5:
+					CHECK(!Data);
+					break;
+				default:
+					CHECK(false);
+					break;
+			}
+		},
+		[&](size_t ChunkIndex, BlockStoreFile& File, uint64_t Offset, uint64_t Size) {
+			switch (ChunkIndex)
+			{
+				case 0:
+				case 1:
+					CHECK(false);
+					break;
+				case 2:
+					{
+						CHECK(Size == VeryLargeChunk.size());
+						char*  Buffer	  = new char[Size];
+						size_t HashOffset = 0;
+						File.StreamByteRange(Offset, Size, [&](const void* Data, uint64_t Size) {
+							memcpy(&Buffer[HashOffset], Data, Size);
+							HashOffset += Size;
+						});
+						CHECK(memcmp(Buffer, VeryLargeChunk.data(), Size) == 0);
+						delete[] Buffer;
+					}
+					break;
+				case 3:
+					CHECK(false);
+					break;
+				case 4:
+					CHECK(false);
+					break;
+				case 5:
+					CHECK(false);
+					break;
+				default:
+					CHECK(false);
+					break;
+			}
+		});
+}
+
+TEST_CASE("blockstore.reclaim.space")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory / "store", 512, 1024, {});
+
+	constexpr size_t				ChunkCount = 200;
+	constexpr size_t				Alignment  = 8;
+	std::vector<BlockStoreLocation> ChunkLocations;
+	std::vector<IoHash>				ChunkHashes;
+	ChunkLocations.reserve(ChunkCount);
+	ChunkHashes.reserve(ChunkCount);
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		IoBuffer Chunk = CreateChunk(57 + ChunkIndex);
+
+		Store.WriteChunk(Chunk.Data(), Chunk.Size(), Alignment, [&](const BlockStoreLocation& L) { ChunkLocations.push_back(L); });
+		ChunkHashes.push_back(IoHash::HashBuffer(Chunk.Data(), Chunk.Size()));
+	}
+
+	std::vector<size_t> ChunksToKeep;
+	ChunksToKeep.reserve(ChunkLocations.size());
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		ChunksToKeep.push_back(ChunkIndex);
+	}
+
+	Store.Flush();
+	BlockStore::ReclaimSnapshotState State1 = Store.GetReclaimSnapshotState();
+	Store.ReclaimSpace(State1, ChunkLocations, ChunksToKeep, Alignment, true);
+
+	// If we keep all the chunks we should not get any callbacks on moved/deleted stuff
+	Store.ReclaimSpace(
+		State1,
+		ChunkLocations,
+		ChunksToKeep,
+		Alignment,
+		false,
+		[](const BlockStore::MovedChunksArray&, const BlockStore::ChunkIndexArray&) { CHECK(false); },
+		[]() {
+			CHECK(false);
+			return 0;
+		});
+
+	size_t DeleteChunkCount = 38;
+	ChunksToKeep.clear();
+	for (size_t ChunkIndex = DeleteChunkCount; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		ChunksToKeep.push_back(ChunkIndex);
+	}
+
+	std::vector<BlockStoreLocation> NewChunkLocations = ChunkLocations;
+	size_t							MovedChunkCount	  = 0;
+	size_t							DeletedChunkCount = 0;
+	Store.ReclaimSpace(
+		State1,
+		ChunkLocations,
+		ChunksToKeep,
+		Alignment,
+		false,
+		[&](const BlockStore::MovedChunksArray& MovedChunks, const BlockStore::ChunkIndexArray& DeletedChunks) {
+			for (const auto& MovedChunk : MovedChunks)
+			{
+				CHECK(MovedChunk.first >= DeleteChunkCount);
+				NewChunkLocations[MovedChunk.first] = MovedChunk.second;
+			}
+			MovedChunkCount += MovedChunks.size();
+			for (size_t DeletedIndex : DeletedChunks)
+			{
+				CHECK(DeletedIndex < DeleteChunkCount);
+			}
+			DeletedChunkCount += DeletedChunks.size();
+		},
+		[]() {
+			CHECK(false);
+			return 0;
+		});
+	CHECK(MovedChunkCount <= DeleteChunkCount);
+	CHECK(DeletedChunkCount == DeleteChunkCount);
+	ChunkLocations = std::vector<BlockStoreLocation>(NewChunkLocations.begin() + DeleteChunkCount, NewChunkLocations.end());
+
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		IoBuffer ChunkBlock = Store.TryGetChunk(NewChunkLocations[ChunkIndex]);
+		if (ChunkIndex >= DeleteChunkCount)
+		{
+			IoBuffer VerifyChunk = Store.TryGetChunk(NewChunkLocations[ChunkIndex]);
+			CHECK(VerifyChunk);
+			IoHash VerifyHash = IoHash::HashBuffer(VerifyChunk.Data(), VerifyChunk.Size());
+			CHECK(VerifyHash == ChunkHashes[ChunkIndex]);
+		}
+	}
+
+	NewChunkLocations = ChunkLocations;
+	MovedChunkCount	  = 0;
+	DeletedChunkCount = 0;
+	Store.ReclaimSpace(
+		State1,
+		ChunkLocations,
+		{},
+		Alignment,
+		false,
+		[&](const BlockStore::MovedChunksArray& MovedChunks, const BlockStore::ChunkIndexArray& DeletedChunks) {
+			CHECK(MovedChunks.empty());
+			DeletedChunkCount += DeletedChunks.size();
+		},
+		[]() {
+			CHECK(false);
+			return 0;
+		});
+	CHECK(DeletedChunkCount == ChunkCount - DeleteChunkCount);
+}
+
+TEST_CASE("blockstore.thread.read.write")
+{
+	using namespace blockstore::impl;
+
+	ScopedTemporaryDirectory TempDir;
+	auto					 RootDirectory = TempDir.Path();
+
+	BlockStore Store;
+	Store.Initialize(RootDirectory / "store", 1088, 1024, {});
+
+	constexpr size_t	  ChunkCount = 1000;
+	constexpr size_t	  Alignment	 = 8;
+	std::vector<IoBuffer> Chunks;
+	std::vector<IoHash>	  ChunkHashes;
+	Chunks.reserve(ChunkCount);
+	ChunkHashes.reserve(ChunkCount);
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		IoBuffer Chunk = CreateChunk(57 + ChunkIndex / 2);
+		Chunks.push_back(Chunk);
+		ChunkHashes.push_back(IoHash::HashBuffer(Chunk.Data(), Chunk.Size()));
+	}
+
+	std::vector<BlockStoreLocation> ChunkLocations;
+	ChunkLocations.resize(ChunkCount);
+
+	WorkerThreadPool	WorkerPool(8);
+	std::atomic<size_t> WorkCompleted = 0;
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		WorkerPool.ScheduleWork([&Store, ChunkIndex, &Chunks, &ChunkLocations, &WorkCompleted]() {
+			IoBuffer& Chunk = Chunks[ChunkIndex];
+			Store.WriteChunk(Chunk.Data(), Chunk.Size(), Alignment, [&](const BlockStoreLocation& L) { ChunkLocations[ChunkIndex] = L; });
+			WorkCompleted.fetch_add(1);
+		});
+	}
+	while (WorkCompleted < Chunks.size())
+	{
+		Sleep(1);
+	}
+
+	WorkCompleted = 0;
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		WorkerPool.ScheduleWork([&Store, ChunkIndex, &ChunkLocations, &ChunkHashes, &WorkCompleted]() {
+			IoBuffer VerifyChunk = Store.TryGetChunk(ChunkLocations[ChunkIndex]);
+			CHECK(VerifyChunk);
+			IoHash VerifyHash = IoHash::HashBuffer(VerifyChunk.Data(), VerifyChunk.Size());
+			CHECK(VerifyHash == ChunkHashes[ChunkIndex]);
+			WorkCompleted.fetch_add(1);
+		});
+	}
+	while (WorkCompleted < Chunks.size())
+	{
+		Sleep(1);
+	}
+
+	std::vector<BlockStoreLocation> SecondChunkLocations;
+	SecondChunkLocations.resize(ChunkCount);
+	WorkCompleted = 0;
+	for (size_t ChunkIndex = 0; ChunkIndex < ChunkCount; ++ChunkIndex)
+	{
+		WorkerPool.ScheduleWork([&Store, ChunkIndex, &Chunks, &SecondChunkLocations, &WorkCompleted]() {
+			IoBuffer& Chunk = Chunks[ChunkIndex];
+			Store.WriteChunk(Chunk.Data(), Chunk.Size(), Alignment, [&](const BlockStoreLocation& L) {
+				SecondChunkLocations[ChunkIndex] = L;
+			});
+			WorkCompleted.fetch_add(1);
+		});
+		WorkerPool.ScheduleWork([&Store, ChunkIndex, &ChunkLocations, &ChunkHashes, &WorkCompleted]() {
+			IoBuffer VerifyChunk = Store.TryGetChunk(ChunkLocations[ChunkIndex]);
+			CHECK(VerifyChunk);
+			IoHash VerifyHash = IoHash::HashBuffer(VerifyChunk.Data(), VerifyChunk.Size());
+			CHECK(VerifyHash == ChunkHashes[ChunkIndex]);
+			WorkCompleted.fetch_add(1);
+		});
+	}
+	while (WorkCompleted < Chunks.size() * 2)
+	{
+		Sleep(1);
+	}
+}
+
+#endif
+
+void
+blockstore_forcelink()
+{
+}
+
+}  // namespace zen