Statediffing geth

* Write state diff to CSV (#2)

* port statediff from https://github.com/jpmorganchase/quorum/blob/9b7fd9af8082795eeeb6863d9746f12b82dd5078/statediff/statediff.go; minor fixes

* integrating state diff extracting, building, and persisting into geth processes

* work towards persisting created statediffs in ipfs; based off github.com/vulcanize/eth-block-extractor

* Add a state diff service

* Remove diff extractor from blockchain

* Update imports

* Move statediff on/off check to geth cmd config

* Update starting state diff service

* Add debugging logs for creating diff

* Add statediff extractor and builder tests and small refactoring

* Start to write statediff to a CSV

* Restructure statediff directory

* Pull CSV publishing methods into their own file

* Reformatting due to go fmt

* Add gomega to vendor dir

* Remove testing focuses

* Update statediff tests to use golang test pkg

instead of ginkgo

- builder_test
- extractor_test
- publisher_test

* Use hexutil.Encode instead of deprecated common.ToHex

* Remove OldValue from DiffBigInt and DiffUint64 fields

* Update builder test

* Remove old storage value from updated accounts

* Remove old values from created/deleted accounts

* Update publisher to account for only storing current account values

* Update service loop and fetching previous block

* Update testing

- remove statediff ginkgo test suite file
- move mocks to their own dir

* Updates per go fmt

* Updates to tests

* Pass statediff mode and path in through cli

* Return filename from publisher

* Remove some duplication in builder

* Remove code field from state diff output

this is the contract byte code, and it can still be obtained by querying
the db by the codeHash

* Consolidate acct diff structs for updated & updated/deleted accts

* Include block number in csv filename

* Clean up error logging

* Cleanup formatting, spelling, etc

* Address PR comments

* Add contract address and storage value to csv

* Refactor accumulating account row in csv publisher

* Add DiffStorage struct

* Add storage key to csv

* Address PR comments

* Fix publisher to include rows for accounts that don't have store updates

* Update builder test after merging in release/1.8

* Update test contract to include storage on contract intialization

- so that we're able to test that storage diffing works for created and
deleted accounts (not just updated accounts).

* Factor out a common trie iterator method in builder

* Apply goimports to statediff

* Apply gosimple changes to statediff

* Gracefully exit geth command(#4)

* Statediff for full node (#6)

* Open a trie from the in-memory database

* Use a node's LeafKey as an identifier instead of the address

It was proving difficult to find look the address up from a given path
with a full node (sometimes the value wouldn't exist in the disk db).
So, instead, for now we are using the node's LeafKey with is a Keccak256
hash of the address, so if we know the address we can figure out which
LeafKey it matches up to.

* Make sure that statediff has been processed before pruning

* Use blockchain stateCache.OpenTrie for storage diffs

* Clean up log lines and remove unnecessary fields from builder

* Apply go fmt changes

* Add a sleep to the blockchain test

* refactoring/reorganizing packages

* refactoring statediff builder and types and adjusted to relay proofs and paths (still need to make this optional)

* refactoring state diff service and adding api which allows for streaming state diff payloads over an rpc websocket subscription

* make proofs and paths optional + compress service loop into single for loop (may be missing something here)

* option to process intermediate nodes

* make state diff rlp serializable

* cli parameter to limit statediffing to select account addresses + test

* review fixes and fixes for issues ran into in integration

* review fixes; proper method signature for api; adjust service so that statediff processing is halted/paused until there is at least one subscriber listening for the results

* adjust buffering to improve stability; doc.go; fix notifier
err handling

* relay receipts with the rest of the data + review fixes/changes

* rpc method to get statediff at specific block; requires archival node or the block be within the pruning range

* fix linter issues

* include total difficulty to the payload

* fix state diff builder: emit actual leaf nodes instead of value nodes; diff on the leaf not on the value; emit correct path for intermediate nodes

* adjust statediff builder tests to changes and extend to test intermediate nodes; golint

* add genesis block to test; handle block 0 in StateDiffAt

* rlp files for mainnet blocks 0-3, for tests

* builder test on mainnet blocks

* common.BytesToHash(path) => crypto.Keaccak256(hash) in builder; BytesToHash produces same hash for e.g. []byte{} and []byte{\x00} - prefix \x00 steps are inconsequential to the hash result

* complete tests for early mainnet blocks

* diff type for representing deleted accounts

* fix builder so that we handle account deletions properly and properly diff storage when an account is moved to a new path; update params

* remove cli params; moving them to subscriber defined

* remove unneeded bc methods

* update service and api; statediffing params are now defined by user through api rather than by service provider by cli

* update top level tests

* add ability to watch specific storage slots (leaf keys) only

* comments; explain logic

* update mainnet blocks test

* update api_test.go

* storage leafkey filter test

* cleanup chain maker

* adjust chain maker for tests to add an empty account in block1 and switch to EIP-158 afterwards (now we just need to generate enough accounts until one causes the empty account to be touched and removed post-EIP-158 so we can simulate and test that process...); also added 2 new blocks where more contract storage is set and old slots are set to zero so they are removed so we can test that

* found an account whose creation causes the empty account to be moved to a new path; this should count as 'touching; the empty account and cause it to be removed according to eip-158... but it doesn't

* use new contract in unit tests that has self-destruct ability, so we can test eip-158 since simply moving an account to new path doesn't count as 'touchin' it

* handle storage deletions

* tests for eip-158 account removal and storage value deletions; there is one edge case left to test where we remove 1 account when only two exist such that the remaining account is moved up and replaces the root branch node

* finish testing known edge cases

* add endpoint to fetch all state and storage nodes at a given blockheight; useful for generating a recent atate cache/snapshot that we can diff forward from rather than needing to collect all diffs from genesis

* test for state trie builder

* if statediffing is on, lock tries in triedb until the statediffing service signals they are done using them

* fix mock blockchain; golint; bump patch

* increase maxRequestContentLength; bump patch

* log the sizes of the state objects we are sending

* CI build (#20)

* CI: run build on PR and on push to master

* CI: debug building geth

* CI: fix coping file

* CI: fix coping file v2

* CI: temporary upload file to release asset

* CI: get release upload_url by tag, upload asset to current relase

* CI: fix tag name

* fix ci build on statediff_at_anyblock-1.9.11 branch

* fix publishing assets in release

* use context deadline for timeout in eth_call

* collect and emit codehash=>code mappings for state objects

* subscription endpoint for retrieving all the codehash=>code mappings that exist at provided height

* Implement WriteStateDiffAt

* Writes state diffs directly to postgres

* Adds CLI flags to configure PG

* Refactors builder output with callbacks

* Copies refactored postgres handling code from ipld-eth-indexer

* rename PostgresCIDWriter.{index->upsert}*

* go.mod update

* rm unused

* cleanup

* output code & codehash iteratively

* had to rf some types for this

* prometheus metrics output

* duplicate recent eth-indexer changes

* migrations and metrics...

* [wip] prom.Init() here? another CLI flag?

* tidy & DRY

* statediff WriteLoop service + CLI flag

* [wip] update test mocks

* todo - do something meaningful to test write loop

* logging

* use geth log

* port tests to go testing

* drop ginkgo/gomega

* fix and cleanup tests

* fail before defer statement

* delete vendor/ dir

* fixes after rebase onto 1.9.23

* fix API registration

* use golang 1.15.5 version (#34)

* bump version meta; add 0.0.11 branch to actions

* bump version meta; update github actions workflows

* statediff: refactor metrics

* Remove redundant statediff/indexer/prom tooling and use existing
prometheus integration.

* "indexer" namespace for metrics

* add reporting loop for db metrics

* doc

* metrics for statediff stats

* metrics namespace/subsystem = statediff/{indexer,service}

* statediff: use a worker pool (for direct writes)

* fix test

* fix chain event subscription

* log tweaks

* func name

* unused import

* intermediate chain event channel for metrics

* update github actions; linting

* add poststate and status to receipt ipld indexes

* stateDiffFor endpoints for fetching or writing statediff object by blockhash; bump statediff version

* fixes after rebase on to v1.10.1

* update github actions and version meta; go fmt

* add leaf key to removed 'nodes'

* include Postgres migrations and schema

* service documentation

* touching up

update github actions after rebase

fix connection leak (misplaced defer) and perform proper rollback on errs

improve error logging; handle PushBlock internal err

* build docker image and publish it to Docker Hub on release

* add access list tx to unit tests

* MarshalBinary and UnmarshalBinary methods for receipt

* fix error caused by 2718 by using MarshalBinary instead of EncodeRLP methods

* ipld encoding/decoding tests

* update TxModel; add AccessListElementModel

* index tx type and access lists

* add access list metrics

* unit tests for tx_type and access list table

* unit tests for receipt marshal/unmarshal binary methods

* improve documentation of the encoding methods

* fix issue identified in linting

Author: elizabethengelman

.github/workflows/on-master.yaml

@@ -0,0 +1,30 @@
+name: Docker Build and publish to Github
+
+on:
+  push:
+    branches:
+      - v1.10.2-statediff
+      - v1.10.1-statediff
+      - v1.9.25-statediff
+      - v1.9.24-statediff
+      - v1.9.23-statediff
+      - v1.9.11-statediff
+
+jobs:
+  build:
+    name: Run docker build and publish
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run docker build
+        run: docker build -t vulcanize/go-ethereum -f Dockerfile .
+      - name: Get the version
+        id: vars
+        run: echo ::set-output name=sha::$(echo ${GITHUB_SHA:0:7})
+      - name: Tag docker image
+        run: docker tag vulcanize/go-ethereum docker.pkg.github.com/vulcanize/go-ethereum/go-ethereum:${{steps.vars.outputs.sha}}
+      - name: Docker Login
+        run: echo ${{ secrets.GITHUB_TOKEN }} | docker login https://docker.pkg.github.com -u vulcanize --password-stdin
+      - name: Docker Push
+        run: docker push docker.pkg.github.com/vulcanize/go-ethereum/go-ethereum:${{steps.vars.outputs.sha}}
+

.github/workflows/on-pr.yml

@@ -0,0 +1,12 @@
+name: Docker Build
+
+on: [pull_request]
+
+jobs:
+  build:
+    name: Run docker build
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+      - name: Run docker build
+        run: docker build -t vulcanize/go-ethereum .

.github/workflows/publish.yaml

@@ -0,0 +1,41 @@
+name: Publish geth to release
+on:
+  release:
+    types: [published]
+jobs:
+  push_to_registries:
+    name: Publish assets to Release
+    runs-on: ubuntu-latest
+    steps:
+      - name: Get the version
+        id: vars
+        run: |
+          echo ::set-output name=sha::$(echo ${GITHUB_SHA:0:7})
+          echo ::set-output name=tag::$(echo ${GITHUB_REF#refs/tags/})
+      - name: Docker Login to Github Registry
+        run: echo ${{ secrets.GITHUB_TOKEN }} | docker login https://docker.pkg.github.com -u vulcanize --password-stdin
+      - name: Docker Pull
+        run: docker pull docker.pkg.github.com/vulcanize/go-ethereum/go-ethereum:${{steps.vars.outputs.sha}}
+      - name: Copy ethereum binary file
+        run: docker run --rm --entrypoint cat docker.pkg.github.com/vulcanize/go-ethereum/go-ethereum:${{steps.vars.outputs.sha}} /usr/local/bin/geth > geth-linux-amd64
+      - name: Docker Login to Docker Registry
+        run: echo ${{ secrets.VULCANIZEJENKINS_PAT }} | docker login -u vulcanizejenkins --password-stdin
+      - name: Tag docker image
+        run: docker tag docker.pkg.github.com/vulcanize/go-ethereum/go-ethereum:${{steps.vars.outputs.sha}} vulcanize/vdb-geth:${{steps.vars.outputs.tag}}
+      - name: Docker Push to Docker Hub
+        run: docker push vulcanize/vdb-geth:${{steps.vars.outputs.tag}}
+      - name: Get release
+        id: get_release
+        uses: bruceadams/[email protected]
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+      - name: Upload Release Asset
+        id: upload-release-asset
+        uses: actions/upload-release-asset@v1
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        with:
+          upload_url: ${{ steps.get_release.outputs.upload_url }}
+          asset_path: geth-linux-amd64
+          asset_name: geth-linux-amd64
+          asset_content_type: application/octet-stream

Dockerfile.amd64

@@ -0,0 +1,7 @@
+# Build Geth in a stock Go builder container
+FROM golang:1.15.5 as builder
+
+#RUN apk add --no-cache make gcc musl-dev linux-headers git
+
+ADD . /go-ethereum
+RUN cd /go-ethereum && make geth

cmd/geth/config.go

@@ -25,6 +25,8 @@ import (
 	"reflect"
 	"unicode"
 
+	"github.com/ethereum/go-ethereum/eth/downloader"
+	"github.com/ethereum/go-ethereum/statediff"
 	"gopkg.in/urfave/cli.v1"
 
 	"github.com/ethereum/go-ethereum/cmd/utils"
@@ -134,6 +136,9 @@ func makeConfigNode(ctx *cli.Context) (*node.Node, gethConfig) {
 		cfg.Ethstats.URL = ctx.GlobalString(utils.EthStatsURLFlag.Name)
 	}
 	applyMetricConfig(ctx, &cfg)
+	if ctx.GlobalBool(utils.StateDiffFlag.Name) {
+		cfg.Eth.Diffing = true
+	}
 
 	return stack, cfg
 }
@@ -144,6 +149,11 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 	if ctx.GlobalIsSet(utils.OverrideBerlinFlag.Name) {
 		cfg.Eth.OverrideBerlin = new(big.Int).SetUint64(ctx.GlobalUint64(utils.OverrideBerlinFlag.Name))
 	}
+
+	if cfg.Eth.SyncMode == downloader.LightSync {
+		return makeLightNode(ctx, stack, cfg)
+	}
+
 	backend, eth := utils.RegisterEthService(stack, &cfg.Eth)
 
 	// Configure catalyst.
@@ -156,6 +166,34 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 		}
 	}
 
+	if ctx.GlobalBool(utils.StateDiffFlag.Name) {
+		var dbParams *statediff.DBParams
+		if ctx.GlobalIsSet(utils.StateDiffDBFlag.Name) {
+			dbParams = new(statediff.DBParams)
+			dbParams.ConnectionURL = ctx.GlobalString(utils.StateDiffDBFlag.Name)
+			if ctx.GlobalIsSet(utils.StateDiffDBNodeIDFlag.Name) {
+				dbParams.ID = ctx.GlobalString(utils.StateDiffDBNodeIDFlag.Name)
+			} else {
+				utils.Fatalf("Must specify node ID for statediff DB output")
+			}
+			if ctx.GlobalIsSet(utils.StateDiffDBClientNameFlag.Name) {
+				dbParams.ClientName = ctx.GlobalString(utils.StateDiffDBClientNameFlag.Name)
+			} else {
+				utils.Fatalf("Must specify client name for statediff DB output")
+			}
+		} else {
+			if ctx.GlobalBool(utils.StateDiffWritingFlag.Name) {
+				utils.Fatalf("Must pass DB parameters if enabling statediff write loop")
+			}
+		}
+		p := statediff.ServiceParams{
+			DBParams:        dbParams,
+			EnableWriteLoop: ctx.GlobalBool(utils.StateDiffWritingFlag.Name),
+			NumWorkers:      ctx.GlobalUint(utils.StateDiffWorkersFlag.Name),
+		}
+		utils.RegisterStateDiffService(stack, eth, &cfg.Eth, p)
+	}
+
 	// Configure GraphQL if requested
 	if ctx.GlobalIsSet(utils.GraphQLEnabledFlag.Name) {
 		utils.RegisterGraphQLService(stack, backend, cfg.Node)
@@ -167,6 +205,20 @@ func makeFullNode(ctx *cli.Context) (*node.Node, ethapi.Backend) {
 	return stack, backend
 }
 
+func makeLightNode(ctx *cli.Context, stack *node.Node, cfg gethConfig) (*node.Node, ethapi.Backend) {
+	backend := utils.RegisterLesEthService(stack, &cfg.Eth)
+
+	// Configure GraphQL if requested
+	if ctx.GlobalIsSet(utils.GraphQLEnabledFlag.Name) {
+		utils.RegisterGraphQLService(stack, backend.ApiBackend, cfg.Node)
+	}
+	// Add the Ethereum Stats daemon if requested.
+	if cfg.Ethstats.URL != "" {
+		utils.RegisterEthStatsService(stack, backend.ApiBackend, cfg.Ethstats.URL)
+	}
+	return stack, backend.ApiBackend
+}
+
 // dumpConfig is the dumpconfig command.
 func dumpConfig(ctx *cli.Context) error {
 	_, cfg := makeConfigNode(ctx)

cmd/geth/main.go

@@ -150,6 +150,12 @@ var (
 		utils.EWASMInterpreterFlag,
 		utils.EVMInterpreterFlag,
 		utils.MinerNotifyFullFlag,
+		utils.StateDiffFlag,
+		utils.StateDiffDBFlag,
+		utils.StateDiffDBNodeIDFlag,
+		utils.StateDiffDBClientNameFlag,
+		utils.StateDiffWritingFlag,
+		utils.StateDiffWorkersFlag,
 		configFileFlag,
 		utils.CatalystFlag,
 	}

cmd/geth/usage.go

@@ -229,6 +229,17 @@ var AppHelpFlagGroups = []flags.FlagGroup{
 			utils.LegacyRPCApiFlag,
 		},
 	},
+	{
+		Name: "STATE DIFF",
+		Flags: []cli.Flag{
+			utils.StateDiffFlag,
+			utils.StateDiffDBFlag,
+			utils.StateDiffDBNodeIDFlag,
+			utils.StateDiffDBClientNameFlag,
+			utils.StateDiffWritingFlag,
+			utils.StateDiffWorkersFlag,
+		},
+	},
 	{
 		Name: "MISC",
 		Flags: []cli.Flag{

cmd/utils/flags.go

@@ -66,6 +66,8 @@ import (
 	"github.com/ethereum/go-ethereum/p2p/nat"
 	"github.com/ethereum/go-ethereum/p2p/netutil"
 	"github.com/ethereum/go-ethereum/params"
+	"github.com/ethereum/go-ethereum/statediff"
+
 	pcsclite "github.com/gballet/go-libpcsclite"
 	gopsutil "github.com/shirou/gopsutil/mem"
 	"gopkg.in/urfave/cli.v1"
@@ -760,6 +762,30 @@ var (
 		Name:  "catalyst",
 		Usage: "Catalyst mode (eth2 integration testing)",
 	}
+	StateDiffFlag = cli.BoolFlag{
+		Name:  "statediff",
+		Usage: "Enables the processing of state diffs between each block",
+	}
+	StateDiffDBFlag = cli.StringFlag{
+		Name:  "statediff.db",
+		Usage: "PostgreSQL database connection string for writing state diffs",
+	}
+	StateDiffDBNodeIDFlag = cli.StringFlag{
+		Name:  "statediff.dbnodeid",
+		Usage: "Node ID to use when writing state diffs to database",
+	}
+	StateDiffDBClientNameFlag = cli.StringFlag{
+		Name:  "statediff.dbclientname",
+		Usage: "Client name to use when writing state diffs to database",
+	}
+	StateDiffWritingFlag = cli.BoolFlag{
+		Name:  "statediff.writing",
+		Usage: "Activates progressive writing of state diffs to database as new block are synced",
+	}
+	StateDiffWorkersFlag = cli.UintFlag{
+		Name:  "statediff.workers",
+		Usage: "Number of concurrent workers to use during statediff processing (0 = 1)",
+	}
 )
 
 // MakeDataDir retrieves the currently requested data directory, terminating
@@ -1000,6 +1026,10 @@ func setWS(ctx *cli.Context, cfg *node.Config) {
 	if ctx.GlobalIsSet(WSPathPrefixFlag.Name) {
 		cfg.WSPathPrefix = ctx.GlobalString(WSPathPrefixFlag.Name)
 	}
+
+	if ctx.GlobalBool(StateDiffFlag.Name) {
+		cfg.WSModules = append(cfg.WSModules, "statediff")
+	}
 }
 
 // setIPC creates an IPC path configuration from the set command line flags,
@@ -1720,6 +1750,15 @@ func RegisterEthService(stack *node.Node, cfg *ethconfig.Config) (ethapi.Backend
 	return backend.APIBackend, backend
 }
 
+// RegisterLesEthService adds an Ethereum les client to the stack.
+func RegisterLesEthService(stack *node.Node, cfg *eth.Config) *les.LightEthereum {
+	backend, err := les.New(stack, cfg)
+	if err != nil {
+		Fatalf("Failed to register the Ethereum service: %v", err)
+	}
+	return backend
+}
+
 // RegisterEthStatsService configures the Ethereum Stats daemon and adds it to
 // the given node.
 func RegisterEthStatsService(stack *node.Node, backend ethapi.Backend, url string) {
@@ -1735,6 +1774,13 @@ func RegisterGraphQLService(stack *node.Node, backend ethapi.Backend, cfg node.C
 	}
 }
 
+// RegisterStateDiffService configures and registers a service to stream state diff data over RPC
+func RegisterStateDiffService(stack *node.Node, ethServ *eth.Ethereum, cfg *ethconfig.Config, params statediff.ServiceParams) {
+	if err := statediff.New(stack, ethServ, cfg, params); err != nil {
+		Fatalf("Failed to register the Statediff service: %v", err)
+	}
+}
+
 func SetupMetrics(ctx *cli.Context) {
 	if metrics.Enabled {
 		log.Info("Enabling metrics collection")

core/blockchain.go

@@ -131,6 +131,7 @@ type CacheConfig struct {
 	Preimages           bool          // Whether to store preimage of trie key to the disk
 
 	SnapshotWait bool // Wait for snapshot construction on startup. TODO(karalabe): This is a dirty hack for testing, nuke it
+	StateDiffing bool // Whether or not the statediffing service is running
 }
 
 // defaultCacheConfig are the default caching values if none are specified by the
@@ -209,6 +210,10 @@ type BlockChain struct {
 
 	shouldPreserve  func(*types.Block) bool        // Function used to determine whether should preserve the given block.
 	terminateInsert func(common.Hash, uint64) bool // Testing hook used to terminate ancient receipt chain insertion.
+
+	// Locked roots and their mutex
+	trieLock    sync.Mutex
+	lockedRoots map[common.Hash]bool
 }
 
 // NewBlockChain returns a fully initialised block chain using information
@@ -245,6 +250,7 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, chainConfig *par
 		futureBlocks:   futureBlocks,
 		engine:         engine,
 		vmConfig:       vmConfig,
+		lockedRoots:    make(map[common.Hash]bool),
 	}
 	bc.validator = NewBlockValidator(chainConfig, bc, engine)
 	bc.prefetcher = newStatePrefetcher(chainConfig, bc, engine)
@@ -1031,7 +1037,10 @@ func (bc *BlockChain) Stop() {
 			}
 		}
 		for !bc.triegc.Empty() {
-			triedb.Dereference(bc.triegc.PopItem().(common.Hash))
+			pruneRoot := bc.triegc.PopItem().(common.Hash)
+			if !bc.TrieLocked(pruneRoot) {
+				triedb.Dereference(pruneRoot)
+			}
 		}
 		if size, _ := triedb.Size(); size != 0 {
 			log.Error("Dangling trie nodes after full cleanup")
@@ -1488,6 +1497,11 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 		triedb.Reference(root, common.Hash{}) // metadata reference to keep trie alive
 		bc.triegc.Push(root, -int64(block.NumberU64()))
 
+		// If we are statediffing, lock the trie until the statediffing service is done using it
+		if bc.cacheConfig.StateDiffing {
+			bc.LockTrie(root)
+		}
+
 		if current := block.NumberU64(); current > TriesInMemory {
 			// If we exceeded our memory allowance, flush matured singleton nodes to disk
 			var (
@@ -1526,7 +1540,11 @@ func (bc *BlockChain) writeBlockWithState(block *types.Block, receipts []*types.
 					bc.triegc.Push(root, number)
 					break
 				}
-				triedb.Dereference(root.(common.Hash))
+				pruneRoot := root.(common.Hash)
+				if !bc.TrieLocked(pruneRoot) {
+					log.Debug("Dereferencing", "root", root.(common.Hash).Hex())
+					triedb.Dereference(pruneRoot)
+				}
 			}
 		}
 	}
@@ -2510,3 +2528,28 @@ func (bc *BlockChain) SubscribeLogsEvent(ch chan<- []*types.Log) event.Subscript
 func (bc *BlockChain) SubscribeBlockProcessingEvent(ch chan<- bool) event.Subscription {
 	return bc.scope.Track(bc.blockProcFeed.Subscribe(ch))
 }
+
+// TrieLocked returns whether the trie associated with the provided root is locked for use
+func (bc *BlockChain) TrieLocked(root common.Hash) bool {
+	bc.trieLock.Lock()
+	locked, ok := bc.lockedRoots[root]
+	bc.trieLock.Unlock()
+	if !ok {
+		return false
+	}
+	return locked
+}
+
+// LockTrie prevents dereferencing of the provided root
+func (bc *BlockChain) LockTrie(root common.Hash) {
+	bc.trieLock.Lock()
+	bc.lockedRoots[root] = true
+	bc.trieLock.Unlock()
+}
+
+// UnlockTrie allows dereferencing of the provided root- provided it was previously locked
+func (bc *BlockChain) UnlockTrie(root common.Hash) {
+	bc.trieLock.Lock()
+	bc.lockedRoots[root] = false
+	bc.trieLock.Unlock()
+}