Re: [PATCH v5 3/5] nfsd: convert nfs4_client->cl_cb_flags to a generic flags field

["J. Bruce Fields" <bfields@fieldses.org>]

On Wed, Feb 01, 2012 at 10:44:10AM -0500, Jeff Layton wrote:
> We'll need a way to flag the nfs4_client as already being recorded on
> stable storage so that we don't continually upcall.

Looks like the code currently uses cl_firststate for that purpose.

I'm perfectly open to the argument that using a u32 to store a boolean
is rather silly, and can't see any problem with doing it this way
instead, but then let's remove cl_firstate while we're at it.

--b.

> 
> The cl_cb_flags field is only using 2 bits right now, so repurpose that
> to a generic flags field. Rename NFSD4_CLIENT_KILL to
> NFSD4_CLIENT_CB_KILL to make it evident that it's part of the callback
> flags. Add a mask that we can use for existing checks that look to see
> whether any flags are set, so that the new STABLE flag doesn't
> interfere.
> 
> Signed-off-by: Jeff Layton <jlayton@redhat.com>
> ---
>  fs/nfsd/nfs4callback.c |   12 ++++++------
>  fs/nfsd/state.h        |    8 +++++---
>  2 files changed, 11 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4callback.c b/fs/nfsd/nfs4callback.c
> index 6f3ebb4..730e2cc 100644
> --- a/fs/nfsd/nfs4callback.c
> +++ b/fs/nfsd/nfs4callback.c
> @@ -756,7 +756,7 @@ void nfsd4_probe_callback(struct nfs4_client *clp)
>  {
>  	/* XXX: atomicity?  Also, should we be using cl_cb_flags? */
>  	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
> -	set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
> +	set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
>  	do_probe_callback(clp);
>  }
>  
> @@ -915,7 +915,7 @@ void nfsd4_destroy_callback_queue(void)
>  /* must be called under the state lock */
>  void nfsd4_shutdown_callback(struct nfs4_client *clp)
>  {
> -	set_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags);
> +	set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
>  	/*
>  	 * Note this won't actually result in a null callback;
>  	 * instead, nfsd4_do_callback_rpc() will detect the killed
> @@ -966,15 +966,15 @@ static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
>  		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
>  		clp->cl_cb_conn.cb_xprt = NULL;
>  	}
> -	if (test_bit(NFSD4_CLIENT_KILL, &clp->cl_cb_flags))
> +	if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
>  		return;
>  	spin_lock(&clp->cl_lock);
>  	/*
>  	 * Only serialized callback code is allowed to clear these
>  	 * flags; main nfsd code can only set them:
>  	 */
> -	BUG_ON(!clp->cl_cb_flags);
> -	clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_cb_flags);
> +	BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
> +	clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
>  	memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
>  	c = __nfsd4_find_backchannel(clp);
>  	if (c) {
> @@ -1000,7 +1000,7 @@ void nfsd4_do_callback_rpc(struct work_struct *w)
>  	struct nfs4_client *clp = cb->cb_clp;
>  	struct rpc_clnt *clnt;
>  
> -	if (clp->cl_cb_flags)
> +	if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
>  		nfsd4_process_cb_update(cb);
>  
>  	clnt = clp->cl_cb_client;
> diff --git a/fs/nfsd/state.h b/fs/nfsd/state.h
> index 8f539ee..0f9a0ac 100644
> --- a/fs/nfsd/state.h
> +++ b/fs/nfsd/state.h
> @@ -250,9 +250,11 @@ struct nfs4_client {
>  
>  	/* for v4.0 and v4.1 callbacks: */
>  	struct nfs4_cb_conn	cl_cb_conn;
> -#define NFSD4_CLIENT_CB_UPDATE	1
> -#define NFSD4_CLIENT_KILL	2
> -	unsigned long		cl_cb_flags;
> +#define NFSD4_CLIENT_STABLE		(0)	/* client on stable storage */
> +#define NFSD4_CLIENT_CB_UPDATE		(1)
> +#define NFSD4_CLIENT_CB_KILL		(2)
> +#define NFSD4_CLIENT_CB_FLAG_MASK	(0x6)
> +	unsigned long		cl_flags;
>  	struct rpc_clnt		*cl_cb_client;
>  	u32			cl_cb_ident;
>  #define NFSD4_CB_UP		0
> -- 
> 1.7.7.6
>