serialize incremental_snapshot_hash (#26839)

* serialize incremental_snapshot_hash

* pr feedback

core/src/accounts_hash_verifier.rs

@@ -190,6 +190,7 @@ impl AccountsHashVerifier {
             accounts_package.snapshot_links.path(),
             accounts_package.slot,
             &accounts_hash,
+            None,
         );
         datapoint_info!(
             "accounts_hash_verifier",

core/tests/snapshots.rs

@@ -256,6 +256,7 @@ fn run_bank_forks_snapshot_n<F>(
         accounts_package.snapshot_links.path(),
         accounts_package.slot,
         &last_bank.get_accounts_hash(),
+        None,
     );
     let snapshot_package = SnapshotPackage::new(accounts_package, last_bank.get_accounts_hash());
     snapshot_utils::archive_snapshot_package(
@@ -491,6 +492,7 @@ fn test_concurrent_snapshot_packaging(
                 accounts_package.snapshot_links.path(),
                 accounts_package.slot,
                 &Hash::default(),
+                None,
             );
             let snapshot_package = SnapshotPackage::new(accounts_package, Hash::default());
             pending_snapshot_package
@@ -534,6 +536,7 @@ fn test_concurrent_snapshot_packaging(
         saved_snapshots_dir.path(),
         saved_slot,
         &Hash::default(),
+        None,
     );
 
     snapshot_utils::verify_snapshot_archive(

runtime/src/bank.rs

@@ -236,6 +236,25 @@ impl RentDebit {
     }
 }
 
+/// Incremental snapshots only calculate their accounts hash based on the account changes WITHIN the incremental slot range.
+/// So, we need to keep track of the full snapshot expected accounts hash results.
+/// We also need to keep track of the hash and capitalization specific to the incremental snapshot slot range.
+/// The capitalization we calculate for the incremental slot will NOT be consistent with the bank's capitalization.
+/// It is not feasible to calculate a capitalization delta that is correct given just incremental slots account data and the full snapshot's capitalization.
+#[derive(Serialize, Deserialize, AbiExample, Clone, Debug, Default, PartialEq, Eq)]
+pub struct BankIncrementalSnapshotPersistence {
+    /// slot of full snapshot
+    pub full_slot: Slot,
+    /// accounts hash from the full snapshot
+    pub full_hash: Hash,
+    /// capitalization from the full snapshot
+    pub full_capitalization: u64,
+    /// hash of the accounts in the incremental snapshot slot range, including zero-lamport accounts
+    pub incremental_hash: Hash,
+    /// capitalization of the accounts in the incremental snapshot slot range
+    pub incremental_capitalization: u64,
+}
+
 #[derive(Clone, Debug, Default, PartialEq, Eq)]
 pub struct RentDebits(HashMap<Pubkey, RentDebit>);
 impl RentDebits {
@@ -976,6 +995,7 @@ pub struct BankFieldsToDeserialize {
     pub(crate) epoch_stakes: HashMap<Epoch, EpochStakes>,
     pub(crate) is_delta: bool,
     pub(crate) accounts_data_len: u64,
+    pub(crate) incremental_snapshot_persistence: Option<BankIncrementalSnapshotPersistence>,
 }
 
 // Bank's common fields shared by all supported snapshot versions for serialization.
@@ -1083,6 +1103,7 @@ impl PartialEq for Bank {
             accounts_data_size_delta_on_chain: _,
             accounts_data_size_delta_off_chain: _,
             fee_structure: _,
+            incremental_snapshot_persistence: _,
             // Ignore new fields explicitly if they do not impact PartialEq.
             // Adding ".." will remove compile-time checks that if a new field
             // is added to the struct, this ParitalEq is accordingly updated.
@@ -1336,6 +1357,8 @@ pub struct Bank {
 
     /// Transaction fee structure
     pub fee_structure: FeeStructure,
+
+    pub incremental_snapshot_persistence: Option<BankIncrementalSnapshotPersistence>,
 }
 
 struct VoteWithStakeDelegations {
@@ -1466,6 +1489,7 @@ impl Bank {
 
     fn default_with_accounts(accounts: Accounts) -> Self {
         let mut bank = Self {
+            incremental_snapshot_persistence: None,
             rewrites_skipped_this_slot: Rewrites::default(),
             rc: BankRc::new(accounts, Slot::default()),
             status_cache: Arc::<RwLock<BankStatusCache>>::default(),
@@ -1765,6 +1789,7 @@ impl Bank {
 
         let accounts_data_size_initial = parent.load_accounts_data_size();
         let mut new = Bank {
+            incremental_snapshot_persistence: None,
             rewrites_skipped_this_slot: Rewrites::default(),
             rc,
             status_cache,
@@ -2126,6 +2151,7 @@ impl Bank {
         }
         let feature_set = new();
         let mut bank = Self {
+            incremental_snapshot_persistence: fields.incremental_snapshot_persistence,
             rewrites_skipped_this_slot: Rewrites::default(),
             rc: bank_rc,
             status_cache: new(),

runtime/src/serde_snapshot.rs

@@ -8,7 +8,7 @@ use {
         accounts_index::AccountSecondaryIndexes,
         accounts_update_notifier_interface::AccountsUpdateNotifier,
         append_vec::{AppendVec, StoredMetaWriteVersion},
-        bank::{Bank, BankFieldsToDeserialize, BankRc},
+        bank::{Bank, BankFieldsToDeserialize, BankIncrementalSnapshotPersistence, BankRc},
         blockhash_queue::BlockhashQueue,
         builtins::Builtins,
         epoch_stakes::EpochStakes,
@@ -77,6 +77,7 @@ pub struct AccountsDbFields<T>(
     /// slots that were roots within the last epoch for which we care about the hash value
     #[serde(deserialize_with = "default_on_eof")]
     Vec<(Slot, Hash)>,
+    // here?
 );
 
 /// Helper type to wrap BufReader streams when deserializing and reconstructing from either just a
@@ -193,6 +194,7 @@ trait TypeContext<'a>: PartialEq {
         stream_reader: &mut BufReader<R>,
         stream_writer: &mut BufWriter<W>,
         accounts_hash: &Hash,
+        incremental_snapshot_persistence: Option<&BankIncrementalSnapshotPersistence>,
     ) -> std::result::Result<(), Box<bincode::ErrorKind>>
     where
         R: Read,
@@ -370,12 +372,18 @@ fn reserialize_bank_fields_with_new_hash<W, R>(
     stream_reader: &mut BufReader<R>,
     stream_writer: &mut BufWriter<W>,
     accounts_hash: &Hash,
+    incremental_snapshot_persistence: Option<&BankIncrementalSnapshotPersistence>,
 ) -> Result<(), Error>
 where
     W: Write,
     R: Read,
 {
-    newer::Context::reserialize_bank_fields_with_hash(stream_reader, stream_writer, accounts_hash)
+    newer::Context::reserialize_bank_fields_with_hash(
+        stream_reader,
+        stream_writer,
+        accounts_hash,
+        incremental_snapshot_persistence,
+    )
 }
 
 /// effectively updates the accounts hash in the serialized bank file on disk
@@ -387,6 +395,7 @@ pub fn reserialize_bank_with_new_accounts_hash(
     bank_snapshots_dir: impl AsRef<Path>,
     slot: Slot,
     accounts_hash: &Hash,
+    incremental_snapshot_persistence: Option<&BankIncrementalSnapshotPersistence>,
 ) -> bool {
     let bank_post = snapshot_utils::get_bank_snapshots_dir(bank_snapshots_dir, slot);
     let bank_post = bank_post.join(snapshot_utils::get_snapshot_file_name(slot));
@@ -404,6 +413,7 @@ pub fn reserialize_bank_with_new_accounts_hash(
                 &mut BufReader::new(file),
                 &mut BufWriter::new(file_out),
                 accounts_hash,
+                incremental_snapshot_persistence,
             )
             .unwrap();
         }

runtime/src/serde_snapshot/newer.rs

@@ -96,6 +96,7 @@ impl From<DeserializableVersionedBank> for BankFieldsToDeserialize {
             stakes: dvb.stakes,
             epoch_stakes: dvb.epoch_stakes,
             is_delta: dvb.is_delta,
+            incremental_snapshot_persistence: None,
         }
     }
 }
@@ -209,6 +210,7 @@ impl<'a> TypeContext<'a> for Context {
             // we can grab it on restart.
             // TODO: if we do a snapshot version bump, consider moving this out.
             lamports_per_signature,
+            None::<BankIncrementalSnapshotPersistence>,
         )
             .serialize(serializer)
     }
@@ -314,6 +316,10 @@ impl<'a> TypeContext<'a> for Context {
         bank_fields.fee_rate_governor = bank_fields
             .fee_rate_governor
             .clone_with_lamports_per_signature(lamports_per_signature);
+
+        let incremental_snapshot_persistence = ignore_eof_error(deserialize_from(stream))?;
+        bank_fields.incremental_snapshot_persistence = incremental_snapshot_persistence;
+
         Ok((bank_fields, accounts_db_fields))
     }
 
@@ -327,12 +333,13 @@ impl<'a> TypeContext<'a> for Context {
     }
 
     /// deserialize the bank from 'stream_reader'
-    /// modify the accounts_hash
+    /// modify the accounts_hash and incremental_snapshot_persistence
     /// reserialize the bank to 'stream_writer'
     fn reserialize_bank_fields_with_hash<R, W>(
         stream_reader: &mut BufReader<R>,
         stream_writer: &mut BufWriter<W>,
         accounts_hash: &Hash,
+        incremental_snapshot_persistence: Option<&BankIncrementalSnapshotPersistence>,
     ) -> std::result::Result<(), Box<bincode::ErrorKind>>
     where
         R: Read,
@@ -345,6 +352,7 @@ impl<'a> TypeContext<'a> for Context {
         let blockhash_queue = RwLock::new(rhs.blockhash_queue.clone());
         let hard_forks = RwLock::new(rhs.hard_forks.clone());
         let lamports_per_signature = rhs.fee_rate_governor.lamports_per_signature;
+
         let bank = SerializableVersionedBank {
             blockhash_queue: &blockhash_queue,
             ancestors: &rhs.ancestors,
@@ -382,7 +390,12 @@ impl<'a> TypeContext<'a> for Context {
 
         bincode::serialize_into(
             stream_writer,
-            &(bank, accounts_db_fields, lamports_per_signature),
+            &(
+                bank,
+                accounts_db_fields,
+                lamports_per_signature,
+                incremental_snapshot_persistence,
+            ),
         )
     }
 }

runtime/src/serde_snapshot/tests.rs

@@ -190,6 +190,7 @@ fn test_bank_serialize_style(
     serde_style: SerdeStyle,
     reserialize_accounts_hash: bool,
     update_accounts_hash: bool,
+    incremental_snapshot_persistence: bool,
 ) {
     solana_logger::setup();
     let (genesis_config, _) = create_genesis_config(500);
@@ -236,8 +237,18 @@ fn test_bank_serialize_style(
     } else {
         bank2.get_accounts_hash()
     };
-    if reserialize_accounts_hash {
-        let slot = bank2.slot();
+
+    let slot = bank2.slot();
+    let incremental =
+        incremental_snapshot_persistence.then(|| BankIncrementalSnapshotPersistence {
+            full_slot: slot + 1,
+            full_hash: Hash::new(&[1; 32]),
+            full_capitalization: 31,
+            incremental_hash: Hash::new(&[2; 32]),
+            incremental_capitalization: 32,
+        });
+
+    if reserialize_accounts_hash || incremental_snapshot_persistence {
         let temp_dir = TempDir::new().unwrap();
         let slot_dir = temp_dir.path().join(slot.to_string());
         let post_path = slot_dir.join(slot.to_string());
@@ -248,21 +259,32 @@ fn test_bank_serialize_style(
             let mut f = std::fs::File::create(&pre_path).unwrap();
             f.write_all(&buf).unwrap();
         }
+
         assert!(reserialize_bank_with_new_accounts_hash(
             temp_dir.path(),
             slot,
-            &accounts_hash
+            &accounts_hash,
+            incremental.as_ref(),
         ));
         let previous_len = buf.len();
         // larger buffer than expected to make sure the file isn't larger than expected
-        let mut buf_reserialized = vec![0; previous_len + 1];
+        let sizeof_none = std::mem::size_of::<u64>();
+        let sizeof_incremental_snapshot_persistence =
+            std::mem::size_of::<Option<BankIncrementalSnapshotPersistence>>();
+        let mut buf_reserialized =
+            vec![0; previous_len + sizeof_incremental_snapshot_persistence + 1];
         {
             let mut f = std::fs::File::open(post_path).unwrap();
             let size = f.read(&mut buf_reserialized).unwrap();
-            assert_eq!(size, previous_len);
+            let expected = if !incremental_snapshot_persistence {
+                previous_len
+            } else {
+                previous_len + sizeof_incremental_snapshot_persistence - sizeof_none
+            };
+            assert_eq!(size, expected);
             buf_reserialized.truncate(size);
         }
-        if update_accounts_hash {
+        if update_accounts_hash || incremental_snapshot_persistence {
             // We cannot guarantee buffer contents are exactly the same if hash is the same.
             // Things like hashsets/maps have randomness in their in-mem representations.
             // This make serialized bytes not deterministic.
@@ -311,6 +333,7 @@ fn test_bank_serialize_style(
     assert_eq!(dbank.get_balance(&key3.pubkey()), 0);
     assert_eq!(dbank.get_accounts_hash(), accounts_hash);
     assert!(bank2 == dbank);
+    assert_eq!(dbank.incremental_snapshot_persistence, incremental);
 }
 
 pub(crate) fn reconstruct_accounts_db_via_serialization(
@@ -359,11 +382,18 @@ fn test_bank_serialize_newer() {
     for (reserialize_accounts_hash, update_accounts_hash) in
         [(false, false), (true, false), (true, true)]
     {
-        test_bank_serialize_style(
-            SerdeStyle::Newer,
-            reserialize_accounts_hash,
-            update_accounts_hash,
-        )
+        for incremental_snapshot_persistence in if reserialize_accounts_hash {
+            [false, true].to_vec()
+        } else {
+            [false].to_vec()
+        } {
+            test_bank_serialize_style(
+                SerdeStyle::Newer,
+                reserialize_accounts_hash,
+                update_accounts_hash,
+                incremental_snapshot_persistence,
+            )
+        }
     }
 }
 
@@ -555,7 +585,7 @@ mod test_bank_serialize {
 
     // This some what long test harness is required to freeze the ABI of
     // Bank's serialization due to versioned nature
-    #[frozen_abi(digest = "9vGBt7YfymKUTPWLHVVpQbDtPD7dFDwXRMFkCzwujNqJ")]
+    #[frozen_abi(digest = "5py4Wkuj5fV2sLyA1MrPg4pGNwMEaygQLnpLyY8MMLGC")]
     #[derive(Serialize, AbiExample)]
     pub struct BankAbiTestWrapperNewer {
         #[serde(serialize_with = "wrapper_newer")]

runtime/src/snapshot_utils.rs

@@ -2045,6 +2045,7 @@ pub fn package_and_archive_full_snapshot(
         accounts_package.snapshot_links.path(),
         accounts_package.slot,
         &bank.get_accounts_hash(),
+        None,
     );
 
     let snapshot_package = SnapshotPackage::new(accounts_package, bank.get_accounts_hash());
@@ -2097,6 +2098,7 @@ pub fn package_and_archive_incremental_snapshot(
         accounts_package.snapshot_links.path(),
         accounts_package.slot,
         &bank.get_accounts_hash(),
+        None,
     );
 
     let snapshot_package = SnapshotPackage::new(accounts_package, bank.get_accounts_hash());