Fix double-locking bug in flush()

yama/src/pile/local_sqlitebloblogs.rs

@@ -527,14 +527,20 @@ impl RawPile for SqliteBloblogPile {
         Ok(Box::new(ki))
     }
     fn flush(&self) -> anyhow::Result<()> {
-        let inner = self.inner.lock().unwrap();
-        let _inner = self
-            .writers_reach_zero
-            .wait_while(inner, |inner| inner.writers_in_progress != 0)
-            .unwrap();
-
+        // must do this before we lock inner.
         self.flush_queued_pointer_writes()?;
 
+        let inner = self.inner.lock().unwrap();
+
+        if inner.writers_in_progress > 0 {
+            let _inner = self
+                .writers_reach_zero
+                .wait_while(inner, |inner| {
+                    inner.writers_in_progress != 0
+                })
+                .unwrap();
+        }
+
         // TODO sync all files we have open first!
         sync();
         Ok(())