Safely migrate to FileSystemStoreV2

Before moving to PaginatedKVStore everywhere we need to use
FileSystemStoreV2 instead of FileSystemStoreV1. This will safely migrate
over to it on first start up. Also adds a test to make sure we handle it
properly.

Author: benthecarman

src/builder.rs

@@ -34,12 +34,13 @@ use lightning::routing::scoring::{
 use lightning::sign::{EntropySource, NodeSigner};
 use lightning::util::config::HTLCInterceptionFlags;
 use lightning::util::persist::{
-	KVStore, CHANNEL_MANAGER_PERSISTENCE_KEY, CHANNEL_MANAGER_PERSISTENCE_PRIMARY_NAMESPACE,
-	CHANNEL_MANAGER_PERSISTENCE_SECONDARY_NAMESPACE,
+	migrate_kv_store_data, KVStore, CHANNEL_MANAGER_PERSISTENCE_KEY,
+	CHANNEL_MANAGER_PERSISTENCE_PRIMARY_NAMESPACE, CHANNEL_MANAGER_PERSISTENCE_SECONDARY_NAMESPACE,
 };
 use lightning::util::ser::ReadableArgs;
 use lightning::util::sweep::OutputSweeper;
 use lightning_persister::fs_store::v1::FilesystemStore;
+use lightning_persister::fs_store::v2::FilesystemStoreV2;
 use vss_client::headers::VssHeaderProvider;
 
 use crate::chain::ChainSource;
@@ -629,15 +630,20 @@ impl NodeBuilder {
 		self.build_with_store(node_entropy, kv_store)
 	}
 
-	/// Builds a [`Node`] instance with a [`FilesystemStore`] backend and according to the options
+	/// Builds a [`Node`] instance with a [`FilesystemStoreV2`] backend and according to the options
 	/// previously configured.
+	///
+	/// If the storage directory contains data from a v1 filesystem store, it will be
+	/// automatically migrated to the v2 format.
 	pub fn build_with_fs_store(&self, node_entropy: NodeEntropy) -> Result<Node, BuildError> {
 		let mut storage_dir_path: PathBuf = self.config.storage_dir_path.clone().into();
 		storage_dir_path.push("fs_store");
 
 		fs::create_dir_all(storage_dir_path.clone())
 			.map_err(|_| BuildError::StoragePathAccessFailed)?;
-		let kv_store = FilesystemStore::new(storage_dir_path);
+
+		let kv_store = open_or_migrate_fs_store(storage_dir_path)?;
+
 		self.build_with_store(node_entropy, kv_store)
 	}
 
@@ -1087,7 +1093,7 @@ impl ArcedNodeBuilder {
 		self.inner.read().unwrap().build(*node_entropy).map(Arc::new)
 	}
 
-	/// Builds a [`Node`] instance with a [`FilesystemStore`] backend and according to the options
+	/// Builds a [`Node`] instance with a [`FilesystemStoreV2`] backend and according to the options
 	/// previously configured.
 	pub fn build_with_fs_store(
 		&self, node_entropy: Arc<NodeEntropy>,
@@ -1998,6 +2004,40 @@ fn build_with_store_internal(
 	})
 }
 
+/// Opens a [`FilesystemStoreV2`], automatically migrating from v1 format if necessary.
+///
+/// If the directory contains v1 data (files at the top level), the data is migrated to v2 format
+/// in a temporary directory, the original is renamed to `fs_store_v1_backup`, and the migrated
+/// directory is moved into place.
+fn open_or_migrate_fs_store(storage_dir_path: PathBuf) -> Result<FilesystemStoreV2, BuildError> {
+	match FilesystemStoreV2::new(storage_dir_path.clone()) {
+		Ok(store) => Ok(store),
+		Err(e) if e.kind() == std::io::ErrorKind::InvalidData => {
+			// The directory contains v1 data, migrate to v2.
+			let mut v1_store = FilesystemStore::new(storage_dir_path.clone());
+
+			let mut v2_dir = storage_dir_path.clone();
+			v2_dir.set_file_name("fs_store_v2_migrating");
+			fs::create_dir_all(v2_dir.clone()).map_err(|_| BuildError::StoragePathAccessFailed)?;
+			let mut v2_store = FilesystemStoreV2::new(v2_dir.clone())
+				.map_err(|_| BuildError::KVStoreSetupFailed)?;
+
+			migrate_kv_store_data(&mut v1_store, &mut v2_store)
+				.map_err(|_| BuildError::KVStoreSetupFailed)?;
+
+			// Swap directories: rename v1 out of the way, move v2 into place.
+			let mut backup_dir = storage_dir_path.clone();
+			backup_dir.set_file_name("fs_store_v1_backup");
+			fs::rename(&storage_dir_path, &backup_dir)
+				.map_err(|_| BuildError::KVStoreSetupFailed)?;
+			fs::rename(&v2_dir, &storage_dir_path).map_err(|_| BuildError::KVStoreSetupFailed)?;
+
+			FilesystemStoreV2::new(storage_dir_path).map_err(|_| BuildError::KVStoreSetupFailed)
+		},
+		Err(_) => Err(BuildError::KVStoreSetupFailed),
+	}
+}
+
 fn optionally_install_rustls_cryptoprovider() {
 	// Acquire a global Mutex, ensuring that only one process at a time install the provider. This
 	// is mostly required for running tests concurrently.

tests/integration_tests_rust.rs

@@ -2487,6 +2487,37 @@ async fn build_0_7_0_node(
 	(balance, node_id)
 }
 
+async fn build_0_7_0_node_fs_store(
+	bitcoind: &BitcoinD, electrsd: &ElectrsD, storage_path: String, esplora_url: String,
+	seed_bytes: [u8; 64],
+) -> (u64, bitcoin::secp256k1::PublicKey) {
+	let mut builder_old = ldk_node_070::Builder::new();
+	builder_old.set_network(bitcoin::Network::Regtest);
+	builder_old.set_storage_dir_path(storage_path);
+	builder_old.set_entropy_seed_bytes(seed_bytes);
+	builder_old.set_chain_source_esplora(esplora_url, None);
+	let node_old = builder_old.build_with_fs_store().unwrap();
+
+	node_old.start().unwrap();
+	let addr_old = node_old.onchain_payment().new_address().unwrap();
+	premine_and_distribute_funds(
+		&bitcoind.client,
+		&electrsd.client,
+		vec![addr_old],
+		Amount::from_sat(100_000),
+	)
+	.await;
+	node_old.sync_wallets().unwrap();
+
+	let balance = node_old.list_balances().spendable_onchain_balance_sats;
+	assert!(balance > 0);
+	let node_id = node_old.node_id();
+
+	node_old.stop().unwrap();
+
+	(balance, node_id)
+}
+
 async fn do_persistence_backwards_compatibility(version: OldLdkVersion) {
 	let (bitcoind, electrsd) = common::setup_bitcoind_and_electrsd();
 	let esplora_url = format!("http://{}", electrsd.esplora_url.as_ref().unwrap());
@@ -2550,6 +2581,52 @@ async fn persistence_backwards_compatibility() {
 	do_persistence_backwards_compatibility(OldLdkVersion::V0_7_0).await;
 }
 
+#[tokio::test(flavor = "multi_thread", worker_threads = 1)]
+async fn fs_store_persistence_backwards_compatibility() {
+	let (bitcoind, electrsd) = common::setup_bitcoind_and_electrsd();
+	let esplora_url = format!("http://{}", electrsd.esplora_url.as_ref().unwrap());
+
+	let storage_path = common::random_storage_path().to_str().unwrap().to_owned();
+	let seed_bytes = [42u8; 64];
+
+	// Build a node using v0.7.0's build_with_fs_store (FilesystemStore v1).
+	let (old_balance, old_node_id) = build_0_7_0_node_fs_store(
+		&bitcoind,
+		&electrsd,
+		storage_path.clone(),
+		esplora_url.clone(),
+		seed_bytes,
+	)
+	.await;
+
+	// Now reopen with current code's build_with_fs_store, which should
+	// auto-migrate from FilesystemStore v1 to FilesystemStoreV2.
+	#[cfg(feature = "uniffi")]
+	let builder_new = Builder::new();
+	#[cfg(not(feature = "uniffi"))]
+	let mut builder_new = Builder::new();
+	builder_new.set_network(bitcoin::Network::Regtest);
+	builder_new.set_storage_dir_path(storage_path);
+	builder_new.set_chain_source_esplora(esplora_url, None);
+
+	#[cfg(feature = "uniffi")]
+	let node_entropy = NodeEntropy::from_seed_bytes(seed_bytes.to_vec()).unwrap();
+	#[cfg(not(feature = "uniffi"))]
+	let node_entropy = NodeEntropy::from_seed_bytes(seed_bytes);
+	let node_new = builder_new.build_with_fs_store(node_entropy.into()).unwrap();
+
+	node_new.start().unwrap();
+	node_new.sync_wallets().unwrap();
+
+	let new_balance = node_new.list_balances().spendable_onchain_balance_sats;
+	let new_node_id = node_new.node_id();
+
+	assert_eq!(old_node_id, new_node_id);
+	assert_eq!(old_balance, new_balance);
+
+	node_new.stop().unwrap();
+}
+
 #[tokio::test(flavor = "multi_thread", worker_threads = 1)]
 async fn onchain_fee_bump_rbf() {
 	let (bitcoind, electrsd) = setup_bitcoind_and_electrsd();