Function lf_advlockasync

freebsd/kern/kern_lockf.c:416–744

* Advisory record locking support */

 * Advisory record locking support
 */
int
lf_advlockasync(struct vop_advlockasync_args *ap, struct lockf **statep,
    u_quad_t size)
{
	struct lockf *state;
	struct flock *fl = ap->a_fl;
	struct lockf_entry *lock;
	struct vnode *vp = ap->a_vp;
	caddr_t id = ap->a_id;
	int flags = ap->a_flags;
	int hash;
	struct lock_owner *lo;
	off_t start, end, oadd;
	int error;

	/*
	 * Handle the F_UNLKSYS case first - no need to mess about
	 * creating a lock owner for this one.
	 */
	if (ap->a_op == F_UNLCKSYS) {
		lf_clearremotesys(fl->l_sysid);
		return (0);
	}

	/*
	 * Convert the flock structure into a start and end.
	 */
	switch (fl->l_whence) {
	case SEEK_SET:
	case SEEK_CUR:
		/*
		 * Caller is responsible for adding any necessary offset
		 * when SEEK_CUR is used.
		 */
		start = fl->l_start;
		break;

	case SEEK_END:
		if (size > OFF_MAX ||
		    (fl->l_start > 0 && size > OFF_MAX - fl->l_start))
			return (EOVERFLOW);
		start = size + fl->l_start;
		break;

	default:
		return (EINVAL);
	}
	if (start < 0)
		return (EINVAL);
	if (fl->l_len < 0) {
		if (start == 0)
			return (EINVAL);
		end = start - 1;
		start += fl->l_len;
		if (start < 0)
			return (EINVAL);
	} else if (fl->l_len == 0) {
		end = OFF_MAX;