wen_restart: Find the bank hash of the heaviest fork, replay if neces…

…sary. (solana-labs#420)

* Find the bank hash of the heaviest fork, replay if necessary.

* Make it more explicit how heaviest fork slot is selected.

* Use process_single_slot instead of process_blockstore_from_root, the latter
may re-insert banks already frozen.

* Put BlockstoreProcessError into the error message.

* Check that all existing blocks link to correct parent before replay.

* Use the default number of threads instead.

* Check whether block is full and other small fixes.

* Fix root_bank and move comments to function level.

* Remove the extra parent link check.

ledger/src/blockstore_processor.rs

@@ -1794,7 +1794,7 @@ fn supermajority_root_from_vote_accounts(
 // Processes and replays the contents of a single slot, returns Error
 // if failed to play the slot
 #[allow(clippy::too_many_arguments)]
-fn process_single_slot(
+pub fn process_single_slot(
     blockstore: &Blockstore,
     bank: &BankWithScheduler,
     replay_tx_thread_pool: &ThreadPool,

wen-restart/Cargo.toml

@@ -15,10 +15,13 @@ anyhow = { workspace = true }
 log = { workspace = true }
 prost = { workspace = true }
 prost-types = { workspace = true }
+rayon = { workspace = true }
+solana-entry = { workspace = true }
 solana-gossip = { workspace = true }
 solana-ledger = { workspace = true }
 solana-logger = { workspace = true }
 solana-program = { workspace = true }
+solana-program-runtime = { workspace = true }
 solana-runtime = { workspace = true }
 solana-sdk = { workspace = true }
 solana-vote-program = { workspace = true }