Re: [PATCH v4 4/8] NFSD add COPY_NOTIFY operation

[bfields@xxxxxxxxxxxx (J. Bruce Fields)]

On Mon, Jul 08, 2019 at 03:23:48PM -0400, Olga Kornievskaia wrote:
> @@ -726,24 +727,53 @@ struct nfs4_stid *nfs4_alloc_stid(struct nfs4_client *cl, struct kmem_cache *sla
>  /*
>   * Create a unique stateid_t to represent each COPY.
>   */
> -int nfs4_init_cp_state(struct nfsd_net *nn, struct nfsd4_copy *copy)
> +static int nfs4_init_cp_state(struct nfsd_net *nn, void *ptr, stateid_t *stid)
>  {
>  	int new_id;
>  
>  	idr_preload(GFP_KERNEL);
>  	spin_lock(&nn->s2s_cp_lock);
> -	new_id = idr_alloc_cyclic(&nn->s2s_cp_stateids, copy, 0, 0, GFP_NOWAIT);
> +	new_id = idr_alloc_cyclic(&nn->s2s_cp_stateids, ptr, 0, 0, GFP_NOWAIT);
>  	spin_unlock(&nn->s2s_cp_lock);
>  	idr_preload_end();
>  	if (new_id < 0)
>  		return 0;
> -	copy->cp_stateid.si_opaque.so_id = new_id;
> -	copy->cp_stateid.si_opaque.so_clid.cl_boot = nn->boot_time;
> -	copy->cp_stateid.si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
> +	stid->si_opaque.so_id = new_id;
> +	stid->si_opaque.so_clid.cl_boot = nn->boot_time;
> +	stid->si_opaque.so_clid.cl_id = nn->s2s_cp_cl_id;
>  	return 1;
>  }
>  
> -void nfs4_free_cp_state(struct nfsd4_copy *copy)
> +int nfs4_init_copy_state(struct nfsd_net *nn, struct nfsd4_copy *copy)
> +{
> +	return nfs4_init_cp_state(nn, copy, &copy->cp_stateid);
> +}

This little bit of refactoring could go into a seperate patch.  It's
easier for me to review lots of smaller patches.

But I don't understand why you're doing it.

Also, I'm a little suspicious of code that doesn't initialize an object
till after it's been added to a global structure.  The more typical
pattern is:


	initialize foo
	take locks, add foo global structure, drop locks.

This prevents anyone doing a lookup from finding "foo" while it's still
in a partially initialized state.

--b.