Allow blacklisting blocks from being finalized again after block revert (#6301)

* Allow blacklisting blocks from being finalized again after block revert

* Use BlockRules for storing unfinalized and add have_state_at in revert

* Move finalization_check in finalize_block upward

* Directly mark finalization blacklist as badblocks

* Remove obselete comment

substrate/client/db/src/lib.rs

@@ -50,8 +50,7 @@ mod subdb;
 use std::sync::Arc;
 use std::path::{Path, PathBuf};
 use std::io;
-use std::collections::HashMap;
-
+use std::collections::{HashMap, HashSet};
 
 use sc_client_api::{
 	UsageInfo, MemoryInfo, IoInfo, MemorySize,
@@ -70,6 +69,7 @@ use parking_lot::RwLock;
 use sp_core::ChangesTrieConfiguration;
 use sp_core::offchain::storage::{OffchainOverlayedChange, OffchainOverlayedChanges};
 use sp_core::storage::{well_known_keys, ChildInfo};
+use sp_arithmetic::traits::Saturating;
 use sp_runtime::{generic::BlockId, Justification, Storage};
 use sp_runtime::traits::{
 	Block as BlockT, Header as HeaderT, NumberFor, Zero, One, SaturatedConversion, HashFor,
@@ -962,6 +962,7 @@ impl<Block: BlockT> Backend<Block> {
 		// TODO: ensure best chain contains this block.
 		let number = *header.number();
 		self.ensure_sequential_finalization(header, last_finalized)?;
+
 		self.note_finalized(
 			transaction,
 			false,
@@ -1015,9 +1016,10 @@ impl<Block: BlockT> Backend<Block> {
 		Ok(())
 	}
 
-	fn try_commit_operation(&self, mut operation: BlockImportOperation<Block>)
-		-> ClientResult<()>
-	{
+	fn try_commit_operation(
+		&self,
+		mut operation: BlockImportOperation<Block>,
+	) -> ClientResult<()> {
 		let mut transaction = Transaction::new();
 		let mut finalization_displaced_leaves = None;
 
@@ -1404,7 +1406,10 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		Ok(())
 	}
 
-	fn commit_operation(&self, operation: Self::BlockImportOperation) -> ClientResult<()> {
+	fn commit_operation(
+		&self,
+		operation: Self::BlockImportOperation,
+	) -> ClientResult<()> {
 		let usage = operation.old_state.usage_info();
 		self.state_usage.merge_sm(usage);
 
@@ -1420,9 +1425,11 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		}
 	}
 
-	fn finalize_block(&self, block: BlockId<Block>, justification: Option<Justification>)
-		-> ClientResult<()>
-	{
+	fn finalize_block(
+		&self,
+		block: BlockId<Block>,
+		justification: Option<Justification>,
+	) -> ClientResult<()> {
 		let mut transaction = Transaction::new();
 		let hash = self.blockchain.expect_block_hash_from_id(&block)?;
 		let header = self.blockchain.expect_header(block)?;
@@ -1488,7 +1495,13 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 		})
 	}
 
-	fn revert(&self, n: NumberFor<Block>, revert_finalized: bool) -> ClientResult<NumberFor<Block>> {
+	fn revert(
+		&self,
+		n: NumberFor<Block>,
+		revert_finalized: bool,
+	) -> ClientResult<(NumberFor<Block>, HashSet<Block::Hash>)> {
+		let mut reverted_finalized = HashSet::new();
+
 		let mut best_number = self.blockchain.info().best_number;
 		let mut best_hash = self.blockchain.info().best_hash;
 
@@ -1507,18 +1520,28 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 					return Ok(c.saturated_into::<NumberFor<Block>>())
 				}
 				let mut transaction = Transaction::new();
+				let removed_number = best_number;
+				let removed = self.blockchain.header(BlockId::Number(best_number))?.ok_or_else(
+					|| sp_blockchain::Error::UnknownBlock(
+						format!("Error reverting to {}. Block hash not found.", best_number)))?;
+				let removed_hash = removed.hash();
+
+				let prev_number = best_number.saturating_sub(One::one());
+				let prev_hash = self.blockchain.hash(prev_number)?.ok_or_else(
+					|| sp_blockchain::Error::UnknownBlock(
+						format!("Error reverting to {}. Block hash not found.", best_number))
+				)?;
+
+				if !self.have_state_at(&prev_hash, prev_number) {
+					return Ok(c.saturated_into::<NumberFor<Block>>())
+				}
+
 				match self.storage.state_db.revert_one() {
 					Some(commit) => {
 						apply_state_commit(&mut transaction, commit);
-						let removed_number = best_number;
-						let removed = self.blockchain.header(BlockId::Number(best_number))?.ok_or_else(
-							|| sp_blockchain::Error::UnknownBlock(
-								format!("Error reverting to {}. Block hash not found.", best_number)))?;
 
-						best_number -= One::one();	// prev block
-						best_hash = self.blockchain.hash(best_number)?.ok_or_else(
-							|| sp_blockchain::Error::UnknownBlock(
-								format!("Error reverting to {}. Block hash not found.", best_number)))?;
+						best_number = prev_number;
+						best_hash = prev_hash;
 
 						let update_finalized = best_number < finalized;
 
@@ -1531,7 +1554,12 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 							),
 						)?;
 						if update_finalized {
-							transaction.set_from_vec(columns::META, meta_keys::FINALIZED_BLOCK, key.clone());
+							transaction.set_from_vec(
+								columns::META,
+								meta_keys::FINALIZED_BLOCK,
+								key.clone()
+							);
+							reverted_finalized.insert(removed_hash);
 						}
 						transaction.set_from_vec(columns::META, meta_keys::BEST_BLOCK, key);
 						transaction.remove(columns::KEY_LOOKUP, removed.hash().as_ref());
@@ -1562,7 +1590,7 @@ impl<Block: BlockT> sc_client_api::backend::Backend<Block> for Backend<Block> {
 
 		revert_leaves()?;
 
-		Ok(reverted)
+		Ok((reverted, reverted_finalized))
 	}
 
 	fn blockchain(&self) -> &BlockchainDb<Block> {
@@ -1986,7 +2014,6 @@ pub(crate) mod tests {
 
 			backend.commit_operation(op).unwrap();
 
-
 			assert!(backend.storage.db.get(
 				columns::STATE,
 				&sp_trie::prefixed_key::<BlakeTwo256>(&key, EMPTY_PREFIX)