Toggle SAFE syncmode on and off automatically

If monerod is started with default sync mode, set it to SAFE after
synchronization completes. Set it back to FAST if synchronization
restarts (e.g. because another peer has a longer blockchain).

If monerod is started with an explicit sync mode, none of this
automation takes effect.

3 files changed, 14 insertions, 0 deletions

diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index 3efb8c3c3..ad246d85e 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -606,6 +606,13 @@ public:
   virtual void sync() = 0;
 
   /**
+   * @brief toggle safe syncs for the DB
+   *
+   * Used to switch DBF_SAFE on or off after starting up with DBF_FAST.
+   */
+  virtual void safesyncmode(const bool onoff) = 0;
+
+  /**
    * @brief Remove everything from the BlockchainDB
    *
    * This function should completely remove all data from a BlockchainDB.
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index a756c04c6..4100d9cca 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -1318,6 +1318,11 @@ void BlockchainLMDB::sync()
   }
 }
 
+void BlockchainLMDB::safesyncmode(const bool onoff)
+{
+  mdb_env_set_flags(m_env, MDB_NOSYNC|MDB_MAPASYNC, !onoff);
+}
+
 void BlockchainLMDB::reset()
 {
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index 14e5d34e2..3a11ddf0d 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -165,6 +165,8 @@ public:
 
   virtual void sync();
 
+  virtual void safesyncmode(const bool onoff);
+
   virtual void reset();
 
   virtual std::vector<std::string> get_filenames() const;