ceph_pg_pool_name_by_id
pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, spec->pool_id);
pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
pool_name = ceph_pg_pool_name_by_id(osdc->osdmap, pool);
extern const char *ceph_pg_pool_name_by_id(struct ceph_osdmap *map, u64 id);
EXPORT_SYMBOL(ceph_pg_pool_name_by_id);