kernel: Move block tree db open to block manager

Before this change the block tree db was needlessly re-opened during
startup when loading a completed snapshot. Improve this by letting the
block manager open it on construction. This also simplifies the test
code a bit.

The change was initially motivated to make it easier for users of the
kernel library to instantiate a BlockManager that may be used to read
data from disk without loading the block index into a cache.

src/bitcoin-chainstate.cpp

@@ -106,6 +106,10 @@ int main(int argc, char* argv[])
     };
     auto notifications = std::make_unique<KernelNotifications>();
 
+    node::CacheSizes cache_sizes;
+    cache_sizes.block_tree_db = 2 << 20;
+    cache_sizes.coins_db = 2 << 22;
+    cache_sizes.coins = (450 << 20) - (2 << 20) - (2 << 22);
 
     // SETUP: Chainstate
     auto chainparams = CChainParams::Main();
@@ -119,14 +123,14 @@ int main(int argc, char* argv[])
         .chainparams = chainman_opts.chainparams,
         .blocks_dir = abs_datadir / "blocks",
         .notifications = chainman_opts.notifications,
+        .block_tree_db_params = DBParams{
+            .path = abs_datadir / "blocks" / "index",
+            .cache_bytes = static_cast<size_t>(cache_sizes.block_tree_db),
+        },
     };
     util::SignalInterrupt interrupt;
     ChainstateManager chainman{interrupt, chainman_opts, blockman_opts};
 
-    node::CacheSizes cache_sizes;
-    cache_sizes.block_tree_db = 2 << 20;
-    cache_sizes.coins_db = 2 << 22;
-    cache_sizes.coins = (450 << 20) - (2 << 20) - (2 << 22);
     node::ChainstateLoadOptions options;
     auto [status, error] = node::LoadChainstate(chainman, cache_sizes, options);
     if (status != node::ChainstateLoadStatus::SUCCESS) {

src/init.cpp

@@ -1056,6 +1056,10 @@ bool AppInitParameterInteraction(const ArgsManager& args)
             .chainparams = chainman_opts_dummy.chainparams,
             .blocks_dir = args.GetBlocksDirPath(),
             .notifications = chainman_opts_dummy.notifications,
+            .block_tree_db_params = DBParams{
+                .path = args.GetDataDirNet() / "blocks" / "index",
+                .cache_bytes = 0,
+            },
         };
         auto blockman_result{ApplyArgsManOptions(args, blockman_opts_dummy)};
         if (!blockman_result) {
@@ -1198,18 +1202,33 @@ static ChainstateLoadResult InitAndLoadChainstate(
         .signals = node.validation_signals.get(),
     };
     Assert(ApplyArgsManOptions(args, chainman_opts)); // no error can happen, already checked in AppInitParameterInteraction
+
     BlockManager::Options blockman_opts{
         .chainparams = chainman_opts.chainparams,
         .blocks_dir = args.GetBlocksDirPath(),
         .notifications = chainman_opts.notifications,
+        .block_tree_db_params = DBParams{
+            .path = args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = static_cast<size_t>(cache_sizes.block_tree_db),
+            .wipe_data = do_reindex,
+        },
     };
     Assert(ApplyArgsManOptions(args, blockman_opts)); // no error can happen, already checked in AppInitParameterInteraction
+
+    // Creating the chainstate manager internally creates a BlockManager, opens
+    // the blocks tree db, and wipes existing block files in case of a reindex.
+    // The coinsdb is opened at a later point on LoadChainstate.
     try {
         node.chainman = std::make_unique<ChainstateManager>(*Assert(node.shutdown_signal), chainman_opts, blockman_opts);
+    } catch (dbwrapper_error& e) {
+        LogError("%s\n", e.what());
+        return {ChainstateLoadStatus::FAILURE, _("Error opening block database")};
     } catch (std::exception& e) {
         return {ChainstateLoadStatus::FAILURE_FATAL, strprintf(Untranslated("Failed to initialize ChainstateManager: %s"), e.what())};
     }
     ChainstateManager& chainman = *node.chainman;
+    if (chainman.m_interrupt) return {ChainstateLoadStatus::INTERRUPTED, {}};
+
     // This is defined and set here instead of inline in validation.h to avoid a hard
     // dependency between validation and index/base, since the latter is not in
     // libbitcoinkernel.
@@ -1232,7 +1251,6 @@ static ChainstateLoadResult InitAndLoadChainstate(
     };
     node::ChainstateLoadOptions options;
     options.mempool = Assert(node.mempool.get());
-    options.wipe_block_tree_db = do_reindex;
     options.wipe_chainstate_db = do_reindex || do_reindex_chainstate;
     options.prune = chainman.m_blockman.IsPruneMode();
     options.check_blocks = args.GetIntArg("-checkblocks", DEFAULT_CHECKBLOCKS);

src/kernel/blockmanager_opts.h

@@ -5,6 +5,7 @@
 #ifndef BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
 #define BITCOIN_KERNEL_BLOCKMANAGER_OPTS_H
 
+#include <dbwrapper.h>
 #include <kernel/notifications_interface.h>
 #include <util/fs.h>
 
@@ -27,6 +28,7 @@ struct BlockManagerOpts {
     bool fast_prune{false};
     const fs::path blocks_dir;
     Notifications& notifications;
+    DBParams block_tree_db_params;
 };
 
 } // namespace kernel

src/kernel/chainstatemanager_opts.h

@@ -42,7 +42,6 @@ struct ChainstateManagerOpts {
     std::optional<uint256> assumed_valid_block{};
     //! If the tip is older than this, the node is considered to be in initial block download.
     std::chrono::seconds max_tip_age{DEFAULT_MAX_TIP_AGE};
-    DBOptions block_tree_db{};
     DBOptions coins_db{};
     CoinsViewOptions coins_view{};
     Notifications& notifications;

src/node/blockmanager_args.cpp

@@ -6,6 +6,7 @@
 
 #include <common/args.h>
 #include <node/blockstorage.h>
+#include <node/database_args.h>
 #include <tinyformat.h>
 #include <util/result.h>
 #include <util/translation.h>
@@ -34,6 +35,8 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& args, BlockManager::Op
 
     if (auto value{args.GetBoolArg("-fastprune")}) opts.fast_prune = *value;
 
+    ReadDatabaseArgs(args, opts.block_tree_db_params.options);
+
     return {};
 }
 } // namespace node

src/node/blockstorage.cpp

@@ -36,6 +36,7 @@
 #include <util/translation.h>
 #include <validation.h>
 
+#include <cstddef>
 #include <map>
 #include <ranges>
 #include <unordered_map>
@@ -1183,7 +1184,19 @@ BlockManager::BlockManager(const util::SignalInterrupt& interrupt, Options opts)
       m_opts{std::move(opts)},
       m_block_file_seq{FlatFileSeq{m_opts.blocks_dir, "blk", m_opts.fast_prune ? 0x4000 /* 16kB */ : BLOCKFILE_CHUNK_SIZE}},
       m_undo_file_seq{FlatFileSeq{m_opts.blocks_dir, "rev", UNDOFILE_CHUNK_SIZE}},
-      m_interrupt{interrupt} {}
+      m_interrupt{interrupt}
+{
+    m_block_tree_db = std::make_unique<BlockTreeDB>(m_opts.block_tree_db_params);
+
+    if (m_opts.block_tree_db_params.wipe_data) {
+        m_block_tree_db->WriteReindexing(true);
+        m_blockfiles_indexed = false;
+        // If we're reindexing in prune mode, wipe away unusable block files and all undo data files
+        if (m_prune_mode) {
+            CleanupBlockRevFiles();
+        }
+    }
+}
 
 class ImportingNow
 {

src/node/chainstate.cpp

@@ -34,34 +34,8 @@ namespace node {
 // to ChainstateManager::InitializeChainstate().
 static ChainstateLoadResult CompleteChainstateInitialization(
     ChainstateManager& chainman,
-    const CacheSizes& cache_sizes,
     const ChainstateLoadOptions& options) EXCLUSIVE_LOCKS_REQUIRED(::cs_main)
 {
-    auto& pblocktree{chainman.m_blockman.m_block_tree_db};
-    // new BlockTreeDB tries to delete the existing file, which
-    // fails if it's still open from the previous loop. Close it first:
-    pblocktree.reset();
-    try {
-        pblocktree = std::make_unique<BlockTreeDB>(DBParams{
-            .path = chainman.m_options.datadir / "blocks" / "index",
-            .cache_bytes = static_cast<size_t>(cache_sizes.block_tree_db),
-            .memory_only = options.block_tree_db_in_memory,
-            .wipe_data = options.wipe_block_tree_db,
-            .options = chainman.m_options.block_tree_db});
-    } catch (dbwrapper_error& err) {
-        LogError("%s\n", err.what());
-        return {ChainstateLoadStatus::FAILURE, _("Error opening block database")};
-    }
-
-    if (options.wipe_block_tree_db) {
-        pblocktree->WriteReindexing(true);
-        chainman.m_blockman.m_blockfiles_indexed = false;
-        //If we're reindexing in prune mode, wipe away unusable block files and all undo data files
-        if (options.prune) {
-            chainman.m_blockman.CleanupBlockRevFiles();
-        }
-    }
-
     if (chainman.m_interrupt) return {ChainstateLoadStatus::INTERRUPTED, {}};
 
     // LoadBlockIndex will load m_have_pruned if we've ever removed a
@@ -203,7 +177,7 @@ ChainstateLoadResult LoadChainstate(ChainstateManager& chainman, const CacheSize
         }
     }
 
-    auto [init_status, init_error] = CompleteChainstateInitialization(chainman, cache_sizes, options);
+    auto [init_status, init_error] = CompleteChainstateInitialization(chainman, options);
     if (init_status != ChainstateLoadStatus::SUCCESS) {
         return {init_status, init_error};
     }
@@ -239,7 +213,7 @@ ChainstateLoadResult LoadChainstate(ChainstateManager& chainman, const CacheSize
         // for the fully validated chainstate.
         chainman.ActiveChainstate().ClearBlockIndexCandidates();
 
-        auto [init_status, init_error] = CompleteChainstateInitialization(chainman, cache_sizes, options);
+        auto [init_status, init_error] = CompleteChainstateInitialization(chainman, options);
         if (init_status != ChainstateLoadStatus::SUCCESS) {
             return {init_status, init_error};
         }

src/node/chainstate.h

@@ -20,12 +20,7 @@ struct CacheSizes;
 
 struct ChainstateLoadOptions {
     CTxMemPool* mempool{nullptr};
-    bool block_tree_db_in_memory{false};
     bool coins_db_in_memory{false};
-    // Whether to wipe the block tree database when loading it. If set, this
-    // will also set a reindexing flag so any existing block data files will be
-    // scanned and added to the database.
-    bool wipe_block_tree_db{false};
     // Whether to wipe the chainstate database when loading it. If set, this
     // will cause the chainstate database to be rebuilt starting from genesis.
     bool wipe_chainstate_db{false};

src/node/chainstatemanager_args.cpp

@@ -49,7 +49,6 @@ util::Result<void> ApplyArgsManOptions(const ArgsManager& args, ChainstateManage
 
     if (auto value{args.GetIntArg("-maxtipage")}) opts.max_tip_age = std::chrono::seconds{*value};
 
-    ReadDatabaseArgs(args, opts.block_tree_db);
     ReadDatabaseArgs(args, opts.coins_db);
     ReadCoinsViewArgs(args, opts.coins_view);
 

src/test/blockmanager_tests.cpp

@@ -33,6 +33,10 @@ BOOST_AUTO_TEST_CASE(blockmanager_find_block_pos)
         .chainparams = *params,
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = notifications,
+        .block_tree_db_params = DBParams{
+            .path = m_args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = 0,
+        },
     };
     BlockManager blockman{*Assert(m_node.shutdown_signal), blockman_opts};
     // simulate adding a genesis block normally
@@ -140,6 +144,10 @@ BOOST_AUTO_TEST_CASE(blockmanager_flush_block_file)
         .chainparams = Params(),
         .blocks_dir = m_args.GetBlocksDirPath(),
         .notifications = notifications,
+        .block_tree_db_params = DBParams{
+            .path = m_args.GetDataDirNet() / "blocks" / "index",
+            .cache_bytes = 0,
+        },
     };
     BlockManager blockman{*Assert(m_node.shutdown_signal), blockman_opts};
 

src/test/util/setup_common.cpp

@@ -62,7 +62,6 @@
 #include <stdexcept>
 
 using namespace util::hex_literals;
-using kernel::BlockTreeDB;
 using node::ApplyArgsManOptions;
 using node::BlockAssembler;
 using node::BlockManager;
@@ -245,14 +244,15 @@ ChainTestingSetup::ChainTestingSetup(const ChainType chainType, TestOpts opts)
             .chainparams = chainman_opts.chainparams,
             .blocks_dir = m_args.GetBlocksDirPath(),
             .notifications = chainman_opts.notifications,
+            .block_tree_db_params = DBParams{
+                .path = m_args.GetDataDirNet() / "blocks" / "index",
+                .cache_bytes = static_cast<size_t>(m_cache_sizes.block_tree_db),
+                .memory_only = opts.block_tree_db_in_memory,
+                .wipe_data = m_args.GetBoolArg("-reindex", false),
+            },
         };
         m_node.chainman = std::make_unique<ChainstateManager>(*Assert(m_node.shutdown_signal), chainman_opts, blockman_opts);
         LOCK(m_node.chainman->GetMutex());
-        m_node.chainman->m_blockman.m_block_tree_db = std::make_unique<BlockTreeDB>(DBParams{
-            .path = m_args.GetDataDirNet() / "blocks" / "index",
-            .cache_bytes = static_cast<size_t>(m_cache_sizes.block_tree_db),
-            .memory_only = true,
-        });
     };
     m_make_chainman();
 }
@@ -278,9 +278,7 @@ void ChainTestingSetup::LoadVerifyActivateChainstate()
     auto& chainman{*Assert(m_node.chainman)};
     node::ChainstateLoadOptions options;
     options.mempool = Assert(m_node.mempool.get());
-    options.block_tree_db_in_memory = m_block_tree_db_in_memory;
     options.coins_db_in_memory = m_coins_db_in_memory;
-    options.wipe_block_tree_db = m_args.GetBoolArg("-reindex", false);
     options.wipe_chainstate_db = m_args.GetBoolArg("-reindex", false) || m_args.GetBoolArg("-reindex-chainstate", false);
     options.prune = chainman.m_blockman.IsPruneMode();
     options.check_blocks = m_args.GetIntArg("-checkblocks", DEFAULT_CHECKBLOCKS);

src/test/validation_chainstatemanager_tests.cpp

@@ -393,6 +393,11 @@ struct SnapshotTestSetup : TestChain100Setup {
                 .chainparams = chainman_opts.chainparams,
                 .blocks_dir = m_args.GetBlocksDirPath(),
                 .notifications = chainman_opts.notifications,
+                .block_tree_db_params = DBParams{
+                    .path = chainman.m_options.datadir / "blocks" / "index",
+                    .cache_bytes = static_cast<size_t>(m_cache_sizes.block_tree_db),
+                    .memory_only = m_block_tree_db_in_memory,
+                },
             };
             // For robustness, ensure the old manager is destroyed before creating a
             // new one.