mvcc: add truncate method to logical log

core/mvcc/persistent_storage/logical_log.rs

@@ -184,4 +184,15 @@ impl LogicalLog {
         let c = self.file.sync(completion)?;
         Ok(IOResult::IO(IOCompletions::Single(c)))
     }
+
+    pub fn truncate(&mut self) -> Result<IOResult<()>> {
+        let completion = Completion::new_trunc(move |result| {
+            if let Err(err) = result {
+                tracing::error!("logical_log_truncate failed: {}", err);
+            }
+        });
+        let c = self.file.truncate(0, completion)?;
+        self.offset = 0;
+        Ok(IOResult::IO(IOCompletions::Single(c)))
+    }
 }

core/mvcc/persistent_storage/mod.rs

@@ -31,6 +31,10 @@ impl Storage {
     pub fn sync(&self) -> Result<IOResult<()>> {
         self.logical_log.write().unwrap().sync()
     }
+
+    pub fn truncate(&self) -> Result<IOResult<()>> {
+        self.logical_log.write().unwrap().truncate()
+    }
 }
 
 impl Debug for Storage {