Function cache_neg_evict

freebsd/kern/vfs_cache.c:1341–1406

}

static bool
cache_neg_evict(void)
{
	struct namecache *ncp, *ncp2;
	struct neglist *nl;
	struct vnode *dvp;
	struct mtx *dvlp;
	struct mtx *blp;
	uint32_t hash;
	u_char nlen;
	bool evicted;

	nl = cache_neg_evict_select_list();
	if (nl == NULL) {
		return (false);
	}

	mtx_lock(&nl->nl_lock);
	ncp = TAILQ_FIRST(&nl->nl_hotlist);
	if (ncp != NULL) {
		cache_neg_demote_locked(ncp);
	}
	ncp = cache_neg_evict_select_entry(nl);
	if (ncp == NULL) {
		counter_u64_add(neg_evict_skipped_empty, 1);
		mtx_unlock(&nl->nl_lock);
		mtx_unlock(&nl->nl_evict_lock);
		return (false);
	}
	nlen = ncp->nc_nlen;
	dvp = ncp->nc_dvp;
	hash = cache_get_hash(ncp->nc_name, nlen, dvp);
	dvlp = VP2VNODELOCK(dvp);
	blp = HASH2BUCKETLOCK(hash);
	mtx_unlock(&nl->nl_lock);
	mtx_unlock(&nl->nl_evict_lock);
	mtx_lock(dvlp);
	mtx_lock(blp);
	/*
	 * Note that since all locks were dropped above, the entry may be
	 * gone or reallocated to be something else.
	 */
	CK_SLIST_FOREACH(ncp2, (NCHHASH(hash)), nc_hash) {
		if (ncp2 == ncp && ncp2->nc_dvp == dvp &&
		    ncp2->nc_nlen == nlen && (ncp2->nc_flag & NCF_NEGATIVE) != 0)
			break;
	}
	if (ncp2 == NULL) {
		counter_u64_add(neg_evict_skipped_missed, 1);
		ncp = NULL;
		evicted = false;
	} else {
		MPASS(dvlp == VP2VNODELOCK(ncp->nc_dvp));
		MPASS(blp == NCP2BUCKETLOCK(ncp));
		SDT_PROBE2(vfs, namecache, evict_negative, done, ncp->nc_dvp,
		    ncp->nc_name);
		cache_zap_locked(ncp);
		counter_u64_add(neg_evicted, 1);