[pnfs] [PATCH 02/11] Refactor NFSv4 callback service

[Benny Halevy]

On Nov. 28, 2007, 6:25 +0200, ricardo.labiaga at netapp.com wrote:
> Prepare the NFSv4 callback service mechanism to understand v4.0 and v4.1
> callbacks.  Create a new function nfs4_callback_up() that contains the minor
> version 0 specific logic.  It is invoked by nfs_callback_up().
> 
> Augment the list of arguments passed to nfs_callback_up() since it will need
> to deal with minor version 1 as well.  Move the creation of the backchannel
> after the rpc_client has been initialized since the rpc_xprt structure will be
> needed to crated the NFSv4.1 callback.
> 
> Signed-off-by: Ricardo Labiaga <ricardo.labiaga at netapp.com>
> ---
>  fs/nfs/callback.c |   35 +++++++++++++++++++++++++----------
>  fs/nfs/callback.h |    2 +-
>  fs/nfs/client.c   |   19 ++++++++++---------
>  3 files changed, 36 insertions(+), 20 deletions(-)
> 
> diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
> index a796be5..2898a6b 100644
> --- a/fs/nfs/callback.c
> +++ b/fs/nfs/callback.c
> @@ -57,7 +57,7 @@ module_param_call(callback_tcpport, param_set_port, param_get_int,
>  /*
>   * This is the callback kernel thread.
>   */
> -static void nfs_callback_svc(struct svc_rqst *rqstp)
> +static void nfs4_callback_svc(struct svc_rqst *rqstp)
>  {
>  	int err;
>  
> @@ -104,10 +104,28 @@ static void nfs_callback_svc(struct svc_rqst *rqstp)
>  	module_put_and_exit(0);
>  }
>  
> +
> +/*
> + * Bring up the NFSv4 callback service
> + */
> +int nfs4_callback_up(struct svc_serv *serv) {
> +	int ret = 0;
> +
> +	ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport,
> +							SVC_SOCK_ANONYMOUS);
> +	if (ret < 0)

This used to be (ret <= 0)...
If the port==0 case is not an error this warrants a separate patch that should be
pushed upstream (so it should precede this one).

> +		return ret;
> +	nfs_callback_tcpport = ret;
> +	dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
> +	ret = svc_create_thread(nfs4_callback_svc, serv);
> +
> +	return ret;
> +}
> +
>  /*
>   * Bring up the server process if it is not already up.
>   */
> -int nfs_callback_up(void)
> +int nfs_callback_up(int minorversion, void *args)
>  {
>  	struct svc_serv *serv;
>  	int ret = 0;
> @@ -123,14 +141,11 @@ int nfs_callback_up(void)
>  	if (!serv)
>  		goto out_err;
>  
> -	ret = svc_makesock(serv, IPPROTO_TCP, nfs_callback_set_tcpport,
> -							SVC_SOCK_ANONYMOUS);
> -	if (ret <= 0)
> -		goto out_destroy;
> -	nfs_callback_tcpport = ret;
> -	dprintk("Callback port = 0x%x\n", nfs_callback_tcpport);
> -
> -	ret = svc_create_thread(nfs_callback_svc, serv);
> +	switch (minorversion) {
> +	case 0:
> +		ret = nfs4_callback_up(serv);
> +		break;
> +	}
>  	if (ret < 0)
>  		goto out_destroy;
>  	nfs_callback_info.serv = serv;
> diff --git a/fs/nfs/callback.h b/fs/nfs/callback.h
> index c2bb14e..be1d755 100644
> --- a/fs/nfs/callback.h
> +++ b/fs/nfs/callback.h
> @@ -63,7 +63,7 @@ extern __be32 nfs4_callback_getattr(struct cb_getattrargs *args, struct cb_getat
>  extern __be32 nfs4_callback_recall(struct cb_recallargs *args, void *dummy);
>  
>  #ifdef CONFIG_NFS_V4
> -extern int nfs_callback_up(void);
> +extern int nfs_callback_up(int minorversion, void *args);
>  extern void nfs_callback_down(void);
>  #else
>  #define nfs_callback_up()	(0)
> diff --git a/fs/nfs/client.c b/fs/nfs/client.c
> index dee739c..8266178 100644
> --- a/fs/nfs/client.c
> +++ b/fs/nfs/client.c
> @@ -113,12 +113,6 @@ static struct nfs_client *nfs_alloc_client(const char *hostname,
>  	if ((clp = kzalloc(sizeof(*clp), GFP_KERNEL)) == NULL)
>  		goto error_0;
>  
> -	if (nfsversion == 4) {
> -		if (nfs_callback_up() < 0)
> -			goto error_2;
> -		__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
> -	}
> -
>  	atomic_set(&clp->cl_count, 1);
>  	clp->cl_cons_state = NFS_CS_INITING;
>  
> @@ -150,7 +144,6 @@ static struct nfs_client *nfs_alloc_client(const char *hostname,
>  error_3:
>  	if (__test_and_clear_bit(NFS_CS_CALLBACK, &clp->cl_res_state))
>  		nfs_callback_down();
> -error_2:
>  	kfree(clp);
>  error_0:
>  	return NULL;
> @@ -909,14 +902,22 @@ static int nfs4_init_client(struct nfs_client *clp,
>  	if (error)
>  		goto error;
>  
> -	/* XXX TODO: Need to start the callback server here */
> -
>  	error = nfs_create_rpc_client(clp, proto, timeo, retrans, authflavour,
>  					RPC_CLNT_CREATE_DISCRTRY);
>  	if (error < 0)
>  		goto error;
>  	memcpy(clp->cl_ipaddr, ip_addr, sizeof(clp->cl_ipaddr));
>  
> +	/* Start the callback server */
> +	error = nfs_callback_up(clp->cl_minorversion,
> +		clp->cl_rpcclient->cl_xprt);
> +	if (error < 0) {
> +		dprintk("%s: failed to start callback. Error = %d\n",
> +			__FUNCTION__, error);
> +		goto error;
> +	}
> +	__set_bit(NFS_CS_CALLBACK, &clp->cl_res_state);
> +
>  	error = nfs_idmap_new(clp);
>  	if (error < 0) {
>  		dprintk("%s: failed to create idmapper. Error = %d\n",