small optimization

0fcb8f0c · Nickolai Zeldovich · 278654b6 · 0fcb8f0c
--- a/fs.c
+++ b/fs.c
@@ -208,6 +208,9 @@ static void *
 evict(void *vkey, void *p)
 {
  struct inode *ip = p;
+  if (ip->ref)
+    return 0;
+
  acquire(&ip->lock);
  if (ip->ref == 0)
    return ip;