hold read-lock when iterating query results

datastore.go

@@ -53,9 +53,8 @@ func NewDatastore(path string, opts *Options) (*Datastore, error) {
 		return nil, err
 	}
 
-	closeLk := sync.RWMutex{}
 	ds := Datastore{
-		accessor: &accessor{ldb: db, syncWrites: true, closeLk: &closeLk},
+		accessor: &accessor{ldb: db, syncWrites: true, closeLk: new(sync.RWMutex)},
 		DB:       db,
 		path:     path,
 	}
@@ -110,8 +109,6 @@ func (a *accessor) Has(key ds.Key) (exists bool, err error) {
 }
 
 func (a *accessor) GetSize(key ds.Key) (size int, err error) {
-	a.closeLk.RLock()
-	defer a.closeLk.RUnlock()
 	return ds.GetBackedSize(a, key)
 }
 
@@ -151,6 +148,8 @@ func (a *accessor) Query(q dsq.Query) (dsq.Results, error) {
 	}
 	r := dsq.ResultsFromIterator(q, dsq.Iterator{
 		Next: func() (dsq.Result, bool) {
+			a.closeLk.RLock()
+			defer a.closeLk.RUnlock()
 			if !next() {
 				return dsq.Result{}, false
 			}