nvme_ns_lock
ret = nvme_ns_lock(npa->npa_ns, level, flags);
ret = nvme_ns_lock(npa->npa_ns, level, flags);
extern bool nvme_ns_lock(nvme_ns_t *, nvme_lock_level_t, nvme_lock_flags_t);
return (nvme_ns_lock(ns, NVME_LOCK_L_READ, NVME_LOCK_F_DONT_BLOCK));
return (nvme_ns_lock(ns, NVME_LOCK_L_WRITE, NVME_LOCK_F_DONT_BLOCK));