validation: rename snapshot chainstate dir

This changes the snapshot's leveldb chainstate dir name from
`chainstate_[blockhash]` to `chainstate_snapshot`. This simplifies
later logic that loads snapshot data, and enforces the limitation
of a single snapshot at any given time.

Since we still need to persis the blockhash of the base block, we
write that out to a file (`chainstate_snapshot/base_blockhash`) for
later use during initialization, so that we can reinitialize the
snapshot chainstate.

Co-authored-by: Russell Yanofsky <russ@yanofsky.org>

1 files changed, 10 insertions, 2 deletions

diff --git a/src/validation.cpp b/src/validation.cpp
index 402a962a04..0bfa17bb2b 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -1515,7 +1515,7 @@ void Chainstate::InitCoinsDB(
     fs::path leveldb_name)
 {
     if (m_from_snapshot_blockhash) {
-        leveldb_name += "_" + m_from_snapshot_blockhash->ToString();
+        leveldb_name += node::SNAPSHOT_CHAINSTATE_SUFFIX;
     }
 
     m_coins_views = std::make_unique<CoinsViews>(
@@ -4837,9 +4837,17 @@ bool ChainstateManager::ActivateSnapshot(
             static_cast<size_t>(current_coinstip_cache_size * SNAPSHOT_CACHE_PERC));
     }
 
-    const bool snapshot_ok = this->PopulateAndValidateSnapshot(
+    bool snapshot_ok = this->PopulateAndValidateSnapshot(
         *snapshot_chainstate, coins_file, metadata);
 
+    // If not in-memory, persist the base blockhash for use during subsequent
+    // initialization.
+    if (!in_memory) {
+        LOCK(::cs_main);
+        if (!node::WriteSnapshotBaseBlockhash(*snapshot_chainstate)) {
+            snapshot_ok = false;
+        }
+    }
     if (!snapshot_ok) {
         WITH_LOCK(::cs_main, this->MaybeRebalanceCaches());
         return false;