S_ISBLK 10 include/linux/device_cgroup.h if (!S_ISBLK(inode->i_mode) && !S_ISCHR(inode->i_mode)) S_ISBLK 2558 include/linux/fs.h #define special_file(m) (S_ISCHR(m)||S_ISBLK(m)||S_ISFIFO(m)||S_ISSOCK(m))