Add GC reserve block logic

1 files changed, 71 insertions, 10 deletions

diff --git a/zenstore/compactcas.cpp b/zenstore/compactcas.cpp
index 8cf6fe229..99f00f5af 100644
--- a/zenstore/compactcas.cpp
+++ b/zenstore/compactcas.cpp
@@ -309,7 +309,7 @@ CasContainerStrategy::InsertChunk(const void* ChunkData, size_t ChunkSize, const
 			WriteBlockIndex += WriteBlock ? 1 : 0;
 			while (m_ChunkBlocks.contains(WriteBlockIndex))
 			{
-				WriteBlockIndex++;
+				WriteBlockIndex = (WriteBlockIndex + 1) & CasDiskLocation::MaxBlockIndex;
 			}
 			auto BlockPath				   = BuildUcasPath(m_BlocksBasePath, WriteBlockIndex);
 			WriteBlock					   = std::make_shared<ChunkBlock>(BlockPath);
@@ -678,6 +678,7 @@ CasContainerStrategy::CollectGarbage(GcContext& GcCtx)
 				if (!NewBlockFile || (WriteOffset + Chunk.size() > m_MaxBlockSize))
 				{
 					NewBlockIndex = m_WriteBlockIndex.load();
+
 					{
 						RwLock::ExclusiveLockScope _l(m_LocationMapLock);
 						if (NewBlockFile)
@@ -695,12 +696,16 @@ CasContainerStrategy::CollectGarbage(GcContext& GcCtx)
 								return;
 							}
 						}
+						if (m_ChunkBlocks.size() == CasDiskLocation::MaxBlockIndex)
+						{
+							throw std::runtime_error(fmt::format("unable to allocate a new block in {}", m_ContainerBaseName));
+						}
 						while (m_ChunkBlocks.contains(NewBlockIndex))
 						{
-							NewBlockIndex++;
+							NewBlockIndex = (NewBlockIndex + 1) & CasDiskLocation::MaxBlockIndex;
 						}
-						auto BlockPath				 = BuildUcasPath(m_BlocksBasePath, NewBlockIndex);
-						NewBlockFile				 = std::make_shared<ChunkBlock>(BlockPath);
+						auto NewBlockPath			 = BuildUcasPath(m_BlocksBasePath, NewBlockIndex);
+						NewBlockFile				 = std::make_shared<ChunkBlock>(NewBlockPath);
 						m_ChunkBlocks[NewBlockIndex] = NewBlockFile;
 					}
 
@@ -714,16 +719,30 @@ CasContainerStrategy::CollectGarbage(GcContext& GcCtx)
 
 					if (Space.Free < m_MaxBlockSize)
 					{
-						ZEN_INFO("garbage collect from '{}' FAILED, required disk space {}, free {}",
+						std::filesystem::path GCReservePath = m_Config.RootDirectory / (m_ContainerBaseName + ".gc.reserve.ucas");
+						if (!std::filesystem::is_regular_file(GCReservePath))
+						{
+							ZEN_INFO("garbage collect from '{}' FAILED, required disk space {}, free {}",
+									 m_Config.RootDirectory / m_ContainerBaseName,
+									 m_MaxBlockSize,
+									 NiceBytes(Space.Free));
+							RwLock::ExclusiveLockScope _l(m_LocationMapLock);
+							m_ChunkBlocks.erase(NewBlockIndex);
+							return;
+						}
+
+						ZEN_INFO("using gc reserve for '{}', disk free {}",
 								 m_Config.RootDirectory / m_ContainerBaseName,
-								 m_MaxBlockSize * m_MaxBlockSize,
 								 NiceBytes(Space.Free));
-						RwLock::ExclusiveLockScope _l(m_LocationMapLock);
-						m_ChunkBlocks.erase(NewBlockIndex);
-						return;
+						auto NewBlockPath = BuildUcasPath(m_BlocksBasePath, NewBlockIndex);
+						std::filesystem::rename(GCReservePath, NewBlockPath);
+						NewBlockFile->Open();
+					}
+					else
+					{
+						NewBlockFile->Create(m_MaxBlockSize);
 					}
 
-					NewBlockFile->Create(m_MaxBlockSize);
 					MovedBlocks.clear();
 					WriteOffset = 0;
 				}
@@ -930,6 +949,7 @@ CasContainerStrategy::OpenContainer(bool IsNewStore)
 	std::filesystem::path SidxPath		 = m_Config.RootDirectory / (m_ContainerBaseName + ".uidx");
 	std::filesystem::path SlogPath		 = m_Config.RootDirectory / (m_ContainerBaseName + ".ulog");
 	std::filesystem::path LegacySobsPath = m_Config.RootDirectory / (m_ContainerBaseName + ".ucas");
+
 	if (IsNewStore)
 	{
 		if (std::filesystem::is_regular_file(LegacySobsPath))
@@ -1177,6 +1197,47 @@ CasContainerStrategy::OpenContainer(bool IsNewStore)
 		m_CurrentInsertOffset = AlignPositon(SmallestBlockSize, m_PayloadAlignment);
 	}
 
+	// Create GC reserve file if possible
+	std::filesystem::path GCReservePath = m_Config.RootDirectory / (m_ContainerBaseName + ".gc.reserve.ucas");
+
+	std::error_code Error;
+	DiskSpace		Space = DiskSpaceInfo(m_Config.RootDirectory, Error);
+	if (Error)
+	{
+		ZEN_ERROR("get disk space in {} FAILED, reason '{}'", m_ContainerBaseName, Error.message());
+		return;
+	}
+
+	BasicFile GCReserveFile;
+	if (std::filesystem::is_regular_file(GCReservePath))
+	{
+		GCReserveFile.Open(GCReservePath, false);
+		std::uint64_t CurrentSize = GCReserveFile.FileSize();
+		if (CurrentSize != m_MaxBlockSize)
+		{
+			if (CurrentSize > m_MaxBlockSize)
+			{
+				GCReserveFile.SetFileSize(m_MaxBlockSize);
+			}
+			else
+			{
+				std::uint64_t ExtraSpace = m_MaxBlockSize - CurrentSize;
+				if (Space.Free >= ExtraSpace)
+				{
+					GCReserveFile.SetFileSize(m_MaxBlockSize);
+				}
+			}
+		}
+	}
+	else
+	{
+		if (Space.Free > m_MaxBlockSize)
+		{
+			GCReserveFile.Open(GCReservePath, true);
+			GCReserveFile.SetFileSize(m_MaxBlockSize);
+		}
+	}
+
 	// TODO: should validate integrity of container files here
 }