LOCKFS_WLOCK
lock = LOCKFS_WLOCK;
case LOCKFS_WLOCK:
if (lockfs.lf_lock != LOCKFS_WLOCK) {
lockfs.lf_lock = LOCKFS_WLOCK;
lf.lf_lock = LOCKFS_WLOCK;
lf.lf_lock = LOCKFS_WLOCK;
lf->lf_lock = LOCKFS_WLOCK;
lf.lf_lock = LOCKFS_WLOCK;
#define ULOCKFS_WLOCK ((1 << LOCKFS_WLOCK)) /* write lock */
#define LOCKFS_IS_WLOCK(LF) ((LF)->lf_lock == LOCKFS_WLOCK)