Linux 文件缓存 (二)

close系统调用1. 首先来到系统调用入口，主要使用__close_fd进行了具体的处理过程(current->files表示进程当前打开文件表信息，fd为需要关闭的文件索引)1048 /*
1049  * Careful here! We test whether the file pointer is NULL before
1050  * releasing the fd. This ensures that one clone task can‘t release
1051  * an fd while another clone is opening it.
1052  */
1053 SYSCALL_DEFINE1(close, unsigned int, fd)
1054 {
1055         int retval = __close_fd(current->files, fd);
1056
1057         /* can‘t restart close syscall because file table entry was cleared */
1058         if (unlikely(retval == -ERESTARTSYS ||
1059                      retval == -ERESTARTNOINTR ||
1060                      retval == -ERESTARTNOHAND ||
1061                      retval == -ERESTART_RESTARTBLOCK))
1062                 retval = -EINTR;
1063
1064         return retval;
1065 }
1066 EXPORT_SYMBOL(sys_close);