gc: added DeletionMode flag to allow gc dry runs

3 files changed, 27 insertions, 0 deletions

diff --git a/zenstore/filecas.cpp b/zenstore/filecas.cpp
index c83f87c1b..0efdc96f5 100644
--- a/zenstore/filecas.cpp
+++ b/zenstore/filecas.cpp
@@ -557,13 +557,24 @@ FileCasStrategy::CollectGarbage(GcContext& GcCtx)
 
 	if (ChunksToDelete.empty())
 	{
+		ZEN_INFO("nothing to delete");
+
 		return;
 	}
 
 	ZEN_INFO("deleting file CAS garbage: {} chunks ({})", ChunksToDelete.size(), NiceBytes(ChunksToDeleteBytes));
 
+	if (GcCtx.IsDeletionMode() == false)
+	{
+		ZEN_INFO("NOTE: not actually deleting anything since deletion is disabled");
+
+		return;
+	}
+
 	for (const IoHash& Hash : ChunksToDelete)
 	{
+		ZEN_TRACE("deleting chunk {}", Hash);
+
 		std::error_code Ec;
 		DeleteChunk(Hash, Ec);
 
diff --git a/zenstore/gc.cpp b/zenstore/gc.cpp
index 3395761d6..c3cb77b69 100644
--- a/zenstore/gc.cpp
+++ b/zenstore/gc.cpp
@@ -11,6 +11,7 @@ struct GcContext::GcState
 {
 	CasChunkSet m_CasChunks;
 	CasChunkSet m_CidChunks;
+	bool		m_DeletionMode = true;
 };
 
 GcContext::GcContext() : m_State(std::make_unique<GcState>())
@@ -45,6 +46,17 @@ GcContext::FilterCas(std::span<const IoHash> Cas, std::function<void(const IoHas
 	m_State->m_CasChunks.FilterChunks(Cas, [&](const IoHash& Hash) { KeepFunc(Hash); });
 }
 
+bool
+GcContext::IsDeletionMode() const
+{
+	return m_State->m_DeletionMode;
+}
+void 
+GcContext::SetDeletionMode(bool NewState)
+{
+	m_State->m_DeletionMode = NewState;
+}
+
 //////////////////////////////////////////////////////////////////////////
 
 GcContributor::GcContributor(CasGc& Gc) : m_Gc(Gc)
@@ -115,6 +127,7 @@ CasGc::CollectGarbage()
 	// First gather reference set
 
 	GcContext GcCtx;
+	GcCtx.SetDeletionMode(false);
 
 	for (GcContributor* Contributor : m_GcContribs)
 	{
diff --git a/zenstore/include/zenstore/gc.h b/zenstore/include/zenstore/gc.h
index d3092d91c..46b588570 100644
--- a/zenstore/include/zenstore/gc.h
+++ b/zenstore/include/zenstore/gc.h
@@ -30,6 +30,9 @@ public:
 	void FilterCids(std::span<const IoHash> Cid, std::function<void(const IoHash&)> KeepFunc);
 	void FilterCas(std::span<const IoHash> Cas, std::function<void(const IoHash&)> KeepFunc);
 
+	bool IsDeletionMode() const;
+	void SetDeletionMode(bool NewState);
+
 private:
 	struct GcState;