cmd, core, tests: add readonly notion in the snapshots

core, cmd: polish pruner configs

cmd, core: polish

core/state/pruner: open the snaps in non-readonly for pruning

cmd, core, tests: add nobuild

core: polish

cmd/geth/snapshot.go

@@ -170,7 +170,14 @@ func pruneState(ctx *cli.Context) error {
 	defer stack.Close()
 
 	chaindb := utils.MakeChainDatabase(ctx, stack, false)
-	pruner, err := pruner.NewPruner(chaindb, stack.ResolvePath(""), stack.ResolvePath(config.Eth.TrieCleanCacheJournal), ctx.Uint64(utils.BloomFilterSizeFlag.Name))
+	defer chaindb.Close()
+
+	prunerconfig := pruner.Config{
+		Datadir:   stack.ResolvePath(""),
+		Cachedir:  stack.ResolvePath(config.Eth.TrieCleanCacheJournal),
+		BloomSize: ctx.Uint64(utils.BloomFilterSizeFlag.Name),
+	}
+	pruner, err := pruner.NewPruner(chaindb, prunerconfig)
 	if err != nil {
 		log.Error("Failed to open snapshot tree", "err", err)
 		return err
@@ -199,12 +206,20 @@ func verifyState(ctx *cli.Context) error {
 	defer stack.Close()
 
 	chaindb := utils.MakeChainDatabase(ctx, stack, true)
+	defer chaindb.Close()
+
 	headBlock := rawdb.ReadHeadBlock(chaindb)
 	if headBlock == nil {
 		log.Error("Failed to load head block")
 		return errors.New("no head block")
 	}
-	snaptree, err := snapshot.New(chaindb, trie.NewDatabase(chaindb), 256, headBlock.Root(), false, false, false)
+	snapconfig := snapshot.Config{
+		CacheSize:  256,
+		Recovery:   false,
+		NoBuild:    true,
+		AsyncBuild: false,
+	}
+	snaptree, err := snapshot.New(snapconfig, chaindb, trie.NewDatabase(chaindb), headBlock.Root())
 	if err != nil {
 		log.Error("Failed to open snapshot tree", "err", err)
 		return err
@@ -479,7 +494,13 @@ func dumpState(ctx *cli.Context) error {
 	if err != nil {
 		return err
 	}
-	snaptree, err := snapshot.New(db, trie.NewDatabase(db), 256, root, false, false, false)
+	snapConfig := snapshot.Config{
+		CacheSize:  256,
+		Recovery:   false,
+		NoBuild:    true,
+		AsyncBuild: false,
+	}
+	snaptree, err := snapshot.New(snapConfig, db, trie.NewDatabase(db), root)
 	if err != nil {
 		return err
 	}

cmd/utils/flags.go

@@ -2198,6 +2198,9 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (*core.BlockChain, ethdb.Data
 	if !ctx.Bool(SnapshotFlag.Name) {
 		cache.SnapshotLimit = 0 // Disabled
 	}
+	// Disable snapshot generation/wiping by default
+	cache.SnapshotNoBuild = true
+
 	if ctx.IsSet(CacheFlag.Name) || ctx.IsSet(CacheTrieFlag.Name) {
 		cache.TrieCleanLimit = ctx.Int(CacheFlag.Name) * ctx.Int(CacheTrieFlag.Name) / 100
 	}
@@ -2206,7 +2209,6 @@ func MakeChain(ctx *cli.Context, stack *node.Node) (*core.BlockChain, ethdb.Data
 	}
 	vmcfg := vm.Config{EnablePreimageRecording: ctx.Bool(VMEnableDebugFlag.Name)}
 
-	// TODO(rjl493456442) disable snapshot generation/wiping if the chain is read only.
 	// Disable transaction indexing/unindexing by default.
 	chain, err := core.NewBlockChain(chainDb, cache, gspec, nil, engine, vmcfg, nil, nil)
 	if err != nil {

core/blockchain.go

@@ -135,7 +135,8 @@ type CacheConfig struct {
 	SnapshotLimit       int           // Memory allowance (MB) to use for caching snapshot entries in memory
 	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
+	SnapshotNoBuild bool // Whether the background generation is allowed
+	SnapshotWait    bool // Wait for snapshot construction on startup. TODO(karalabe): This is a dirty hack for testing, nuke it
 }
 
 // defaultCacheConfig are the default caching values if none are specified by the
@@ -399,7 +400,13 @@ func NewBlockChain(db ethdb.Database, cacheConfig *CacheConfig, genesis *Genesis
 			log.Warn("Enabling snapshot recovery", "chainhead", head.NumberU64(), "diskbase", *layer)
 			recover = true
 		}
-		bc.snaps, _ = snapshot.New(bc.db, bc.stateCache.TrieDB(), bc.cacheConfig.SnapshotLimit, head.Root(), !bc.cacheConfig.SnapshotWait, true, recover)
+		snapconfig := snapshot.Config{
+			CacheSize:  bc.cacheConfig.SnapshotLimit,
+			Recovery:   recover,
+			NoBuild:    bc.cacheConfig.SnapshotNoBuild,
+			AsyncBuild: !bc.cacheConfig.SnapshotWait,
+		}
+		bc.snaps, _ = snapshot.New(snapconfig, bc.db, bc.stateCache.TrieDB(), head.Root())
 	}
 
 	// Start future block processor.

core/state/pruner/pruner.go

@@ -63,6 +63,13 @@ var (
 	emptyCode = crypto.Keccak256(nil)
 )
 
+// Config includes all the configurations for pruning.
+type Config struct {
+	Datadir   string // The directory of the state database
+	Cachedir  string // The directory of state clean cache
+	BloomSize uint64 // The Megabytes of memory allocated to bloom-filter
+}
+
 // Pruner is an offline tool to prune the stale state with the
 // help of the snapshot. The workflow of pruner is very simple:
 //
@@ -75,40 +82,44 @@ var (
 // periodically in order to release the disk usage and improve the
 // disk read performance to some extent.
 type Pruner struct {
-	db            ethdb.Database
-	stateBloom    *stateBloom
-	datadir       string
-	trieCachePath string
-	headHeader    *types.Header
-	snaptree      *snapshot.Tree
+	config      Config
+	chainHeader *types.Header
+	db          ethdb.Database
+	stateBloom  *stateBloom
+	snaptree    *snapshot.Tree
 }
 
 // NewPruner creates the pruner instance.
-func NewPruner(db ethdb.Database, datadir, trieCachePath string, bloomSize uint64) (*Pruner, error) {
+func NewPruner(db ethdb.Database, config Config) (*Pruner, error) {
 	headBlock := rawdb.ReadHeadBlock(db)
 	if headBlock == nil {
 		return nil, errors.New("Failed to load head block")
 	}
-	snaptree, err := snapshot.New(db, trie.NewDatabase(db), 256, headBlock.Root(), false, false, false)
+	snapconfig := snapshot.Config{
+		CacheSize:  256,
+		Recovery:   false,
+		NoBuild:    true,
+		AsyncBuild: false,
+	}
+	snaptree, err := snapshot.New(snapconfig, db, trie.NewDatabase(db), headBlock.Root())
 	if err != nil {
 		return nil, err // The relevant snapshot(s) might not exist
 	}
 	// Sanitize the bloom filter size if it's too small.
-	if bloomSize < 256 {
-		log.Warn("Sanitizing bloomfilter size", "provided(MB)", bloomSize, "updated(MB)", 256)
-		bloomSize = 256
+	if config.BloomSize < 256 {
+		log.Warn("Sanitizing bloomfilter size", "provided(MB)", config.BloomSize, "updated(MB)", 256)
+		config.BloomSize = 256
 	}
-	stateBloom, err := newStateBloomWithSize(bloomSize)
+	stateBloom, err := newStateBloomWithSize(config.BloomSize)
 	if err != nil {
 		return nil, err
 	}
 	return &Pruner{
-		db:            db,
-		stateBloom:    stateBloom,
-		datadir:       datadir,
-		trieCachePath: trieCachePath,
-		headHeader:    headBlock.Header(),
-		snaptree:      snaptree,
+		config:      config,
+		chainHeader: headBlock.Header(),
+		db:          db,
+		stateBloom:  stateBloom,
+		snaptree:    snaptree,
 	}, nil
 }
 
@@ -236,12 +247,12 @@ func (p *Pruner) Prune(root common.Hash) error {
 	// reuse it for pruning instead of generating a new one. It's
 	// mandatory because a part of state may already be deleted,
 	// the recovery procedure is necessary.
-	_, stateBloomRoot, err := findBloomFilter(p.datadir)
+	_, stateBloomRoot, err := findBloomFilter(p.config.Datadir)
 	if err != nil {
 		return err
 	}
 	if stateBloomRoot != (common.Hash{}) {
-		return RecoverPruning(p.datadir, p.db, p.trieCachePath)
+		return RecoverPruning(p.config.Datadir, p.db, p.config.Cachedir)
 	}
 	// If the target state root is not specified, use the HEAD-127 as the
 	// target. The reason for picking it is:
@@ -252,7 +263,7 @@ func (p *Pruner) Prune(root common.Hash) error {
 		// Retrieve all snapshot layers from the current HEAD.
 		// In theory there are 128 difflayers + 1 disk layer present,
 		// so 128 diff layers are expected to be returned.
-		layers = p.snaptree.Snapshots(p.headHeader.Root, 128, true)
+		layers = p.snaptree.Snapshots(p.chainHeader.Root, 128, true)
 		if len(layers) != 128 {
 			// Reject if the accumulated diff layers are less than 128. It
 			// means in most of normal cases, there is no associated state
@@ -294,7 +305,7 @@ func (p *Pruner) Prune(root common.Hash) error {
 		}
 	} else {
 		if len(layers) > 0 {
-			log.Info("Selecting bottom-most difflayer as the pruning target", "root", root, "height", p.headHeader.Number.Uint64()-127)
+			log.Info("Selecting bottom-most difflayer as the pruning target", "root", root, "height", p.chainHeader.Number.Uint64()-127)
 		} else {
 			log.Info("Selecting user-specified state as the pruning target", "root", root)
 		}
@@ -303,7 +314,7 @@ func (p *Pruner) Prune(root common.Hash) error {
 	// It's necessary otherwise in the next restart we will hit the
 	// deleted state root in the "clean cache" so that the incomplete
 	// state is picked for usage.
-	deleteCleanTrieCache(p.trieCachePath)
+	deleteCleanTrieCache(p.config.Cachedir)
 
 	// All the state roots of the middle layer should be forcibly pruned,
 	// otherwise the dangling state will be left.
@@ -325,7 +336,7 @@ func (p *Pruner) Prune(root common.Hash) error {
 	if err := extractGenesis(p.db, p.stateBloom); err != nil {
 		return err
 	}
-	filterName := bloomFilterName(p.datadir, root)
+	filterName := bloomFilterName(p.config.Datadir, root)
 
 	log.Info("Writing state bloom to disk", "name", filterName)
 	if err := p.stateBloom.Commit(filterName, filterName+stateBloomFileTempSuffix); err != nil {
@@ -362,7 +373,13 @@ func RecoverPruning(datadir string, db ethdb.Database, trieCachePath string) err
 	// - The state HEAD is rewound already because of multiple incomplete `prune-state`
 	// In this case, even the state HEAD is not exactly matched with snapshot, it
 	// still feasible to recover the pruning correctly.
-	snaptree, err := snapshot.New(db, trie.NewDatabase(db), 256, headBlock.Root(), false, false, true)
+	snapconfig := snapshot.Config{
+		CacheSize:  256,
+		Recovery:   true,
+		NoBuild:    true,
+		AsyncBuild: false,
+	}
+	snaptree, err := snapshot.New(snapconfig, db, trie.NewDatabase(db), headBlock.Root())
 	if err != nil {
 		return err // The relevant snapshot(s) might not exist
 	}

core/state/snapshot/journal.go

@@ -120,7 +120,7 @@ func loadAndParseJournal(db ethdb.KeyValueStore, base *diskLayer) (snapshot, jou
 }
 
 // loadSnapshot loads a pre-existing state snapshot backed by a key-value store.
-func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash, recovery bool) (snapshot, bool, error) {
+func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, root common.Hash, cache int, recovery bool, noBuild bool) (snapshot, bool, error) {
 	// If snapshotting is disabled (initial sync in progress), don't do anything,
 	// wait for the chain to permit us to do something meaningful
 	if rawdb.ReadSnapshotDisabled(diskdb) {
@@ -164,13 +164,16 @@ func loadSnapshot(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int,
 		// disk layer.
 		log.Warn("Snapshot is not continuous with chain", "snaproot", head, "chainroot", root)
 	}
-	// Everything loaded correctly, resume any suspended operations
+	// Load the disk layer status from the generator if it's not complete
 	if !generator.Done {
-		// Whether or not wiping was in progress, load any generator progress too
 		base.genMarker = generator.Marker
 		if base.genMarker == nil {
 			base.genMarker = []byte{}
 		}
+	}
+	// Everything loaded correctly, resume any suspended operations
+	// if the background generation is allowed
+	if !generator.Done && !noBuild {
 		base.genPending = make(chan struct{})
 		base.genAbort = make(chan chan *generatorStats)
 

core/state/snapshot/snapshot.go

@@ -148,6 +148,14 @@ type snapshot interface {
 	StorageIterator(account common.Hash, seek common.Hash) (StorageIterator, bool)
 }
 
+// Config includes the configurations for snapshots.
+type Config struct {
+	CacheSize  int  // Megabytes permitted to use for read caches
+	Recovery   bool // Indicator that the snapshots is in the recovery mode
+	NoBuild    bool // Indicator that the snapshots generation is disallowed
+	AsyncBuild bool // The snapshot generation is allowed to be constructed asynchronously
+}
+
 // Tree is an Ethereum state snapshot tree. It consists of one persistent base
 // layer backed by a key-value store, on top of which arbitrarily many in-memory
 // diff layers are topped. The memory diffs can form a tree with branching, but
@@ -158,9 +166,9 @@ type snapshot interface {
 // storage data to avoid expensive multi-level trie lookups; and to allow sorted,
 // cheap iteration of the account/storage tries for sync aid.
 type Tree struct {
+	config Config                   // Snapshots configurations
 	diskdb ethdb.KeyValueStore      // Persistent database to store the snapshot
 	triedb *trie.Database           // In-memory cache to access the trie through
-	cache  int                      // Megabytes permitted to use for read caches
 	layers map[common.Hash]snapshot // Collection of all known layers
 	lock   sync.RWMutex
 
@@ -183,26 +191,27 @@ type Tree struct {
 //     This case happens when the snapshot is 'ahead' of the state trie.
 //   - otherwise, the entire snapshot is considered invalid and will be recreated on
 //     a background thread.
-func New(diskdb ethdb.KeyValueStore, triedb *trie.Database, cache int, root common.Hash, async bool, rebuild bool, recovery bool) (*Tree, error) {
+func New(config Config, diskdb ethdb.KeyValueStore, triedb *trie.Database, root common.Hash) (*Tree, error) {
 	// Create a new, empty snapshot tree
 	snap := &Tree{
+		config: config,
 		diskdb: diskdb,
 		triedb: triedb,
-		cache:  cache,
 		layers: make(map[common.Hash]snapshot),
 	}
-	if !async {
+	// Create the building waiter iff the background generation is allowed
+	if !config.NoBuild && !config.AsyncBuild {
 		defer snap.waitBuild()
 	}
 	// Attempt to load a previously persisted snapshot and rebuild one if failed
-	head, disabled, err := loadSnapshot(diskdb, triedb, cache, root, recovery)
+	head, disabled, err := loadSnapshot(diskdb, triedb, root, config.CacheSize, config.Recovery, config.NoBuild)
 	if disabled {
 		log.Warn("Snapshot maintenance disabled (syncing)")
 		return snap, nil
 	}
 	if err != nil {
-		if rebuild {
-			log.Warn("Failed to load snapshot, regenerating", "err", err)
+		log.Warn("Failed to load snapshot", "err", err)
+		if !config.NoBuild {
 			snap.Rebuild(root)
 			return snap, nil
 		}
@@ -727,7 +736,7 @@ func (t *Tree) Rebuild(root common.Hash) {
 	// generator will run a wiper first if there's not one running right now.
 	log.Info("Rebuilding state snapshot")
 	t.layers = map[common.Hash]snapshot{
-		root: generateSnapshot(t.diskdb, t.triedb, t.cache, root),
+		root: generateSnapshot(t.diskdb, t.triedb, t.config.CacheSize, root),
 	}
 }
 

tests/state_test_util.go

@@ -267,7 +267,13 @@ func MakePreState(db ethdb.Database, accounts core.GenesisAlloc, snapshotter boo
 
 	var snaps *snapshot.Tree
 	if snapshotter {
-		snaps, _ = snapshot.New(db, sdb.TrieDB(), 1, root, false, true, false)
+		snapconfig := snapshot.Config{
+			CacheSize:  1,
+			Recovery:   false,
+			NoBuild:    false,
+			AsyncBuild: false,
+		}
+		snaps, _ = snapshot.New(snapconfig, db, sdb.TrieDB(), root)
 	}
 	statedb, _ = state.New(root, sdb, snaps)
 	return snaps, statedb