ZFS_OBJ_MUTEX
mutex_enter(ZFS_OBJ_MUTEX((zfsvfs), (obj_num)))
mutex_tryenter(ZFS_OBJ_MUTEX((zfsvfs), (obj_num)))
mutex_exit(ZFS_OBJ_MUTEX((zfsvfs), (obj_num)))
ASSERT(MUTEX_HELD(ZFS_OBJ_MUTEX(zfsvfs, zp->z_id)));
ASSERT(MUTEX_HELD(ZFS_OBJ_MUTEX(zp->z_zfsvfs, zp->z_id)) ||