diff --git a/crates/librqbit/src/session_persistence/json.rs b/crates/librqbit/src/session_persistence/json.rs
index 7ed44b5..cda4e69 100644
--- a/crates/librqbit/src/session_persistence/json.rs
+++ b/crates/librqbit/src/session_persistence/json.rs
@@ -85,6 +85,8 @@ impl JsonSessionPersistenceStore {
     }
 
     async fn flush(&self) -> anyhow::Result<()> {
+        // we don't need the write lock technically, but we need to stop concurrent modifications
+        let db_content = self.db_content.write().await;
         let tmp_filename = format!("{}.tmp", self.db_filename.to_str().unwrap());
         let mut tmp = tokio::fs::OpenOptions::new()
             .create(true)
@@ -96,8 +98,7 @@ impl JsonSessionPersistenceStore {
         trace!(?tmp_filename, "opened temp file");
 
         let mut buf = Vec::new();
-        serde_json::to_writer(&mut buf, &*self.db_content.read().await)
-            .context("error serializing")?;
+        serde_json::to_writer(&mut buf, &*db_content).context("error serializing")?;
 
         trace!(?tmp_filename, "serialized DB as JSON");
         tmp.write_all(&buf)