core, eth: abort snapshot generation on snap sync and resume later

core/rawdb/accessors_snapshot.go

@@ -24,6 +24,26 @@ import (
 	"github.com/ethereum/go-ethereum/log"
 )
 
+// ReadSnapshotDisabled retrieves if the snapshot maintenance is disabled.
+func ReadSnapshotDisabled(db ethdb.KeyValueReader) bool {
+	disabled, _ := db.Has(snapshotDisabledKey)
+	return disabled
+}
+
+// WriteSnapshotDisabled stores the snapshot pause flag.
+func WriteSnapshotDisabled(db ethdb.KeyValueWriter) {
+	if err := db.Put(snapshotDisabledKey, []byte("42")); err != nil {
+		log.Crit("Failed to store snapshot disabled flag", "err", err)
+	}
+}
+
+// DeleteSnapshotDisabled deletes the flag keeping the snapshot maintenance disabled.
+func DeleteSnapshotDisabled(db ethdb.KeyValueWriter) {
+	if err := db.Delete(snapshotDisabledKey); err != nil {
+		log.Crit("Failed to remove snapshot disabled flag", "err", err)
+	}
+}
+
 // ReadSnapshotRoot retrieves the root of the block whose state is contained in
 // the persisted snapshot.
 func ReadSnapshotRoot(db ethdb.KeyValueReader) common.Hash {

core/rawdb/database.go

@@ -371,9 +371,9 @@ func InspectDatabase(db ethdb.Database, keyPrefix, keyStart []byte) error {
 			var accounted bool
 			for _, meta := range [][]byte{
 				databaseVersionKey, headHeaderKey, headBlockKey, headFastBlockKey, lastPivotKey,
-				fastTrieProgressKey, snapshotRootKey, snapshotJournalKey, snapshotGeneratorKey,
-				snapshotRecoveryKey, txIndexTailKey, fastTxLookupLimitKey, uncleanShutdownKey,
-				badBlockKey,
+				fastTrieProgressKey, snapshotDisabledKey, snapshotRootKey, snapshotJournalKey,
+				snapshotGeneratorKey, snapshotRecoveryKey, txIndexTailKey, fastTxLookupLimitKey,
+				uncleanShutdownKey, badBlockKey,
 			} {
 				if bytes.Equal(key, meta) {
 					metadata.Add(size)

core/rawdb/schema.go

@@ -45,6 +45,9 @@ var (
 	// fastTrieProgressKey tracks the number of trie entries imported during fast sync.
 	fastTrieProgressKey = []byte("TrieSync")
 
+	// snapshotDisabledKey flags that the snapshot should not be maintained due to initial sync.
+	snapshotDisabledKey = []byte("SnapshotDisabled")
+
 	// snapshotRootKey tracks the hash of the last snapshot.
 	snapshotRootKey = []byte("SnapshotRoot")