--- a/src/fs.c	Tue Jan 22 15:48:35 2019 +0900
+++ b/src/fs.c	Tue Jan 22 17:32:06 2019 +0900
@@ -453,7 +453,7 @@
     st->size = ip->size;
 }
 
-__code cbc_readi (struct inode *ip, char *dst, uint off, uint n, struct file *f, __code (*next)(int ret))
+__code cbc_readi (struct inode *ip, char *dst, uint off, uint n, __code (*next)(int ret))
 {
     uint tot, m;
     struct buf *bp;
@@ -463,7 +463,7 @@
             goto next(-1);
         }
 
-        goto cbc_devsw[ip->major].read(ip, dst, n, f, next);
+        goto cbc_devsw[ip->major].read(ip, dst, n, next);
     }
 
     if (off > ip->size || off + n < off) {
@@ -481,10 +481,6 @@
         brelse(bp);
     }
 
-    if (n > 0)
-        f->off += n;
-    iunlock(f->ip);
-
     goto next(n);
 }