Re: [PATCH] nfsd4: handle failure to find backchannel

[Kinglong Mee <kinglongmee@gmail.com>]

On 7/12/2014 05:16, J. Bruce Fields wrote:
> The local variable "ses" will be left NULL here in the case we fail to
> find a connection.  Spotted by a coverity scan.
>     
> Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> 
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index 2c73cae9899d..fe22cd5c42d3 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -1001,14 +1001,18 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
>  	}
>  	spin_unlock(&clp->cl_lock);
>  
> +	if (!c)
> +		goto out_no_connection;

Setting err to -EINVAL maybe better.
Otherwise, nfsd4_mark_cb_down will be called with err == 0.

>  	err = setup_callback_client(clp, &conn, ses);

setup_callback_client also return -EINVAL when ses == NULL with conn.cb_xprt == NULL.

thanks,
Kinglong Mee

> -	if (err) {
> -		nfsd4_mark_cb_down(clp, err);
> -		return;
> -	}
> +	if (err)
> +		goto out_no_connection;
>  	/* Yay, the callback channel's back! Restart any callbacks: */
>  	list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
>  		run_nfsd4_cb(cb);
> +	return;
> +out_no_connection:
> +	nfsd4_mark_cb_down(clp, err);
> +	return;
>  }
>  
>  static void nfsd4_do_callback_rpc(struct work_struct *w)
> --
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