Function lf_iteratelocks_sysid

freebsd/kern/kern_lockf.c:1868–1928

STAILQ_HEAD(lockdesclist, lockdesc);

int
lf_iteratelocks_sysid(int sysid, lf_iterator *fn, void *arg)
{
	struct lockf *ls;
	struct lockf_entry *lf;
	struct lockdesc *ldesc;
	struct lockdesclist locks;
	int error;

	/*
	 * In order to keep the locking simple, we iterate over the
	 * active lock lists to build a list of locks that need
	 * releasing. We then call the iterator for each one in turn.
	 *
	 * We take an extra reference to the vnode for the duration to
	 * make sure it doesn't go away before we are finished.
	 */
	STAILQ_INIT(&locks);
	sx_xlock(&lf_lock_states_lock);
	LIST_FOREACH(ls, &lf_lock_states, ls_link) {
		sx_xlock(&ls->ls_lock);
		LIST_FOREACH(lf, &ls->ls_active, lf_link) {
			if (lf->lf_owner->lo_sysid != sysid)
				continue;

			ldesc = malloc(sizeof(struct lockdesc), M_LOCKF,
			    M_WAITOK);
			ldesc->vp = lf->lf_vnode;
			vref(ldesc->vp);
			ldesc->fl.l_start = lf->lf_start;
			if (lf->lf_end == OFF_MAX)
				ldesc->fl.l_len = 0;
			else
				ldesc->fl.l_len =
					lf->lf_end - lf->lf_start + 1;
			ldesc->fl.l_whence = SEEK_SET;
			ldesc->fl.l_type = F_UNLCK;
			ldesc->fl.l_pid = lf->lf_owner->lo_pid;
			ldesc->fl.l_sysid = sysid;
			STAILQ_INSERT_TAIL(&locks, ldesc, link);
		}
		sx_xunlock(&ls->ls_lock);
	}
	sx_xunlock(&lf_lock_states_lock);

	/*
	 * Call the iterator function for each lock in turn. If the
	 * iterator returns an error code, just free the rest of the
	 * lockdesc structures.
	 */
	error = 0;
	while ((ldesc = STAILQ_FIRST(&locks)) != NULL) {
		STAILQ_REMOVE_HEAD(&locks, link);
		if (!error)
			error = fn(ldesc->vp, &ldesc->fl, arg);
		vrele(ldesc->vp);
		free(ldesc, M_LOCKF);
	}