DMU_POOL_CHECKSUM_SALT
rc = zap_lookup(spa, &dir, DMU_POOL_CHECKSUM_SALT, 1,
strcmp(attr.za_name, DMU_POOL_CHECKSUM_SALT) == 0) {
DMU_POOL_CHECKSUM_SALT, 1,
DMU_POOL_CHECKSUM_SALT) == ENOENT) {
DMU_POOL_DIRECTORY_OBJECT, DMU_POOL_CHECKSUM_SALT, 1,