Function dbuf_destroy

freebsd/contrib/openzfs/module/zfs/dbuf.c:2727–2843

}

void
dbuf_destroy(dmu_buf_impl_t *db)
{
	dnode_t *dn;
	dmu_buf_impl_t *parent = db->db_parent;
	dmu_buf_impl_t *dndb;

	ASSERT(MUTEX_HELD(&db->db_mtx));
	ASSERT(zfs_refcount_is_zero(&db->db_holds));

	if (db->db_buf != NULL) {
		arc_buf_destroy(db->db_buf, db);
		db->db_buf = NULL;
	}

	if (db->db_blkid == DMU_BONUS_BLKID) {
		int slots = DB_DNODE(db)->dn_num_slots;
		int bonuslen = DN_SLOTS_TO_BONUSLEN(slots);
		if (db->db.db_data != NULL) {
			kmem_free(db->db.db_data, bonuslen);
			arc_space_return(bonuslen, ARC_SPACE_BONUS);
			db->db_state = DB_UNCACHED;
			DTRACE_SET_STATE(db, "buffer cleared");
		}
	}

	dbuf_clear_data(db);

	if (multilist_link_active(&db->db_cache_link)) {
		ASSERT(db->db_caching_status == DB_DBUF_CACHE ||
		    db->db_caching_status == DB_DBUF_METADATA_CACHE);

		multilist_remove(dbuf_caches[db->db_caching_status].cache, db);
		(void) zfs_refcount_remove_many(
		    &dbuf_caches[db->db_caching_status].size,
		    db->db.db_size, db);

		if (db->db_caching_status == DB_DBUF_METADATA_CACHE) {
			DBUF_STAT_BUMPDOWN(metadata_cache_count);
		} else {
			DBUF_STAT_BUMPDOWN(cache_levels[db->db_level]);
			DBUF_STAT_BUMPDOWN(cache_count);
			DBUF_STAT_DECR(cache_levels_bytes[db->db_level],
			    db->db.db_size);
		}
		db->db_caching_status = DB_NO_CACHE;
	}

	ASSERT(db->db_state == DB_UNCACHED || db->db_state == DB_NOFILL);
	ASSERT(db->db_data_pending == NULL);
	ASSERT(list_is_empty(&db->db_dirty_records));

	db->db_state = DB_EVICTING;
	DTRACE_SET_STATE(db, "buffer eviction started");
	db->db_blkptr = NULL;

	/*
	 * Now that db_state is DB_EVICTING, nobody else can find this via