core: move overlay conversion code to its own file (#266)

core/overlay_transition.go

@@ -0,0 +1,245 @@
+// Copyright 2023 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package core
+
+import (
+	"bufio"
+	"bytes"
+	"fmt"
+	"io"
+	"os"
+	"time"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/core/rawdb"
+	"github.com/ethereum/go-ethereum/core/state"
+	"github.com/ethereum/go-ethereum/core/types"
+	"github.com/ethereum/go-ethereum/crypto"
+	"github.com/ethereum/go-ethereum/log"
+	"github.com/ethereum/go-ethereum/rlp"
+	"github.com/ethereum/go-ethereum/trie"
+)
+
+// OverlayVerkleTransition contains the overlay conversion logic
+func OverlayVerkleTransition(statedb *state.StateDB) error {
+	migrdb := statedb.Database()
+
+	// verkle transition: if the conversion process is in progress, move
+	// N values from the MPT into the verkle tree.
+	if migrdb.InTransition() {
+		var (
+			now             = time.Now()
+			tt              = statedb.GetTrie().(*trie.TransitionTrie)
+			mpt             = tt.Base()
+			vkt             = tt.Overlay()
+			hasPreimagesBin = false
+			preimageSeek    = migrdb.GetCurrentPreimageOffset()
+			fpreimages      *bufio.Reader
+		)
+
+		// TODO: avoid opening the preimages file here and make it part of, potentially, statedb.Database().
+		filePreimages, err := os.Open("preimages.bin")
+		if err != nil {
+			// fallback on reading the db
+			log.Warn("opening preimage file", "error", err)
+		} else {
+			defer filePreimages.Close()
+			if _, err := filePreimages.Seek(preimageSeek, io.SeekStart); err != nil {
+				return fmt.Errorf("seeking preimage file: %s", err)
+			}
+			fpreimages = bufio.NewReader(filePreimages)
+			hasPreimagesBin = true
+		}
+
+		accIt, err := statedb.Snaps().AccountIterator(mpt.Hash(), migrdb.GetCurrentAccountHash())
+		if err != nil {
+			return err
+		}
+		defer accIt.Release()
+		accIt.Next()
+
+		// If we're about to start with the migration process, we have to read the first account hash preimage.
+		if migrdb.GetCurrentAccountAddress() == nil {
+			var addr common.Address
+			if hasPreimagesBin {
+				if _, err := io.ReadFull(fpreimages, addr[:]); err != nil {
+					return fmt.Errorf("reading preimage file: %s", err)
+				}
+			} else {
+				addr = common.BytesToAddress(rawdb.ReadPreimage(migrdb.DiskDB(), accIt.Hash()))
+				if len(addr) != 20 {
+					return fmt.Errorf("addr len is zero is not 32: %d", len(addr))
+				}
+			}
+			migrdb.SetCurrentAccountAddress(addr)
+			if migrdb.GetCurrentAccountHash() != accIt.Hash() {
+				return fmt.Errorf("preimage file does not match account hash: %s != %s", crypto.Keccak256Hash(addr[:]), accIt.Hash())
+			}
+			preimageSeek += int64(len(addr))
+		}
+
+		const maxMovedCount = 10000
+		// mkv will be assiting in the collection of up to maxMovedCount key values to be migrated to the VKT.
+		// It has internal caches to do efficient MPT->VKT key calculations, which will be discarded after
+		// this function.
+		mkv := newKeyValueMigrator()
+		// move maxCount accounts into the verkle tree, starting with the
+		// slots from the previous account.
+		count := 0
+
+		// if less than maxCount slots were moved, move to the next account
+		for count < maxMovedCount {
+			acc, err := types.FullAccount(accIt.Account())
+			if err != nil {
+				log.Error("Invalid account encountered during traversal", "error", err)
+				return err
+			}
+			vkt.SetStorageRootConversion(*migrdb.GetCurrentAccountAddress(), acc.Root)
+
+			// Start with processing the storage, because once the account is
+			// converted, the `stateRoot` field loses its meaning. Which means
+			// that it opens the door to a situation in which the storage isn't
+			// converted, but it can not be found since the account was and so
+			// there is no way to find the MPT storage from the information found
+			// in the verkle account.
+			// Note that this issue can still occur if the account gets written
+			// to during normal block execution. A mitigation strategy has been
+			// introduced with the `*StorageRootConversion` fields in VerkleDB.
+			if acc.HasStorage() {
+				stIt, err := statedb.Snaps().StorageIterator(mpt.Hash(), accIt.Hash(), migrdb.GetCurrentSlotHash())
+				if err != nil {
+					return err
+				}
+				stIt.Next()
+
+				// fdb.StorageProcessed will be initialized to `true` if the
+				// entire storage for an account was not entirely processed
+				// by the previous block. This is used as a signal to resume
+				// processing the storage for that account where we left off.
+				// If the entire storage was processed, then the iterator was
+				// created in vain, but it's ok as this will not happen often.
+				for ; !migrdb.GetStorageProcessed() && count < maxMovedCount; count++ {
+					var (
+						value     []byte   // slot value after RLP decoding
+						safeValue [32]byte // 32-byte aligned value
+					)
+					if err := rlp.DecodeBytes(stIt.Slot(), &value); err != nil {
+						return fmt.Errorf("error decoding bytes %x: %w", stIt.Slot(), err)
+					}
+					copy(safeValue[32-len(value):], value)
+
+					var slotnr []byte
+					if hasPreimagesBin {
+						var s [32]byte
+						slotnr = s[:]
+						if _, err := io.ReadFull(fpreimages, slotnr); err != nil {
+							return fmt.Errorf("reading preimage file: %s", err)
+						}
+					} else {
+						slotnr = rawdb.ReadPreimage(migrdb.DiskDB(), stIt.Hash())
+						if len(slotnr) != 32 {
+							return fmt.Errorf("slotnr len is zero is not 32: %d", len(slotnr))
+						}
+					}
+					if crypto.Keccak256Hash(slotnr[:]) != stIt.Hash() {
+						return fmt.Errorf("preimage file does not match storage hash: %s!=%s", crypto.Keccak256Hash(slotnr), stIt.Hash())
+					}
+					preimageSeek += int64(len(slotnr))
+
+					mkv.addStorageSlot(migrdb.GetCurrentAccountAddress().Bytes(), slotnr, safeValue[:])
+
+					// advance the storage iterator
+					migrdb.SetStorageProcessed(!stIt.Next())
+					if !migrdb.GetStorageProcessed() {
+						migrdb.SetCurrentSlotHash(stIt.Hash())
+					}
+				}
+				stIt.Release()
+			}
+
+			// If the maximum number of leaves hasn't been reached, then
+			// it means that the storage has finished processing (or none
+			// was available for this account) and that the account itself
+			// can be processed.
+			if count < maxMovedCount {
+				count++ // count increase for the account itself
+
+				mkv.addAccount(migrdb.GetCurrentAccountAddress().Bytes(), acc)
+				vkt.ClearStrorageRootConversion(*migrdb.GetCurrentAccountAddress())
+
+				// Store the account code if present
+				if !bytes.Equal(acc.CodeHash, types.EmptyCodeHash[:]) {
+					code := rawdb.ReadCode(statedb.Database().DiskDB(), common.BytesToHash(acc.CodeHash))
+					chunks := trie.ChunkifyCode(code)
+
+					mkv.addAccountCode(migrdb.GetCurrentAccountAddress().Bytes(), uint64(len(code)), chunks)
+				}
+
+				// reset storage iterator marker for next account
+				migrdb.SetStorageProcessed(false)
+				migrdb.SetCurrentSlotHash(common.Hash{})
+
+				// Move to the next account, if available - or end
+				// the transition otherwise.
+				if accIt.Next() {
+					var addr common.Address
+					if hasPreimagesBin {
+						if _, err := io.ReadFull(fpreimages, addr[:]); err != nil {
+							return fmt.Errorf("reading preimage file: %s", err)
+						}
+					} else {
+						addr = common.BytesToAddress(rawdb.ReadPreimage(migrdb.DiskDB(), accIt.Hash()))
+						if len(addr) != 20 {
+							return fmt.Errorf("account address len is zero is not 20: %d", len(addr))
+						}
+					}
+					// fmt.Printf("account switch: %s != %s\n", crypto.Keccak256Hash(addr[:]), accIt.Hash())
+					if crypto.Keccak256Hash(addr[:]) != accIt.Hash() {
+						return fmt.Errorf("preimage file does not match account hash: %s != %s", crypto.Keccak256Hash(addr[:]), accIt.Hash())
+					}
+					preimageSeek += int64(len(addr))
+					migrdb.SetCurrentAccountAddress(addr)
+				} else {
+					// case when the account iterator has
+					// reached the end but count < maxCount
+					migrdb.EndVerkleTransition()
+					break
+				}
+			}
+		}
+		migrdb.SetCurrentPreimageOffset(preimageSeek)
+
+		log.Info("Collected key values from base tree", "count", count, "duration", time.Since(now), "last account", statedb.Database().GetCurrentAccountHash())
+
+		// Take all the collected key-values and prepare the new leaf values.
+		// This fires a background routine that will start doing the work that
+		// migrateCollectedKeyValues() will use to insert into the tree.
+		//
+		// TODO: Now both prepare() and migrateCollectedKeyValues() are next to each other, but
+		//       after we fix an existing bug, we can call prepare() before the block execution and
+		//       let it do the work in the background. After the block execution and finalization
+		//       finish, we can call migrateCollectedKeyValues() which should already find everything ready.
+		mkv.prepare()
+		now = time.Now()
+		if err := mkv.migrateCollectedKeyValues(tt.Overlay()); err != nil {
+			return fmt.Errorf("could not migrate key values: %w", err)
+		}
+		log.Info("Inserted key values in overlay tree", "count", count, "duration", time.Since(now))
+	}
+
+	return nil
+}