fix(fs): deadlock when get link error (#963)

pkg/singleflight/singleflight.go

@@ -74,6 +74,7 @@ type Group[T any] struct {
 	mu sync.Mutex          // protects m
 	m  map[string]*call[T] // lazily initialized
 
+	// Won't remember error
 	Remember bool
 }
 
@@ -158,7 +159,7 @@ func (g *Group[T]) doCall(c *call[T], key string, fn func() (T, error)) {
 		g.mu.Lock()
 		defer g.mu.Unlock()
 		c.wg.Done()
-		if !g.Remember && g.m[key] == c {
+		if (!g.Remember || c.err != nil) && g.m[key] == c {
 			delete(g.m, key)
 		}