Re: [PATCH v2 1/1] nfsd4: Expose the callback address and state of each NFS4 client

[Bruce Fields <bfields@fieldses.org>]

When I run trace-cmd report I get output like:

  [nfsd:nfsd_cb_state] function cb_state2str not defined
  [nfsd:nfsd_cb_shutdown] function cb_state2str not defined
  [nfsd:nfsd_cb_probe] function cb_state2str not defined
  [nfsd:nfsd_cb_lost] function cb_state2str not defined

I don't know how this is supposed to work.  Is it OK for tracepoint definitions
to reference kernel functions if they're defined in the right way somehow?  If
not, I don't know what the solution would be for sharing this--define a macro
that expands to the array literal and use that in both places?  Or maybe just
live with the the redundancy.

--b.

On Mon, May 17, 2021 at 04:29:45PM -0400, Dave Wysochanski wrote:
> In addition to the client's address, display the callback channel
> state and address in the 'info' file.  Define and use a common
> function for this information that can be used by both callback
> trace events and the NFS4 client 'info' file.
> 
> Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
> ---
>  fs/nfsd/nfs4state.c |  2 ++
>  fs/nfsd/trace.c     | 15 +++++++++++++++
>  fs/nfsd/trace.h     |  9 ++-------
>  3 files changed, 19 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> index b2573d3ecd3c..f3b8221bb543 100644
> --- a/fs/nfsd/nfs4state.c
> +++ b/fs/nfsd/nfs4state.c
> @@ -2385,6 +2385,8 @@ static int client_info_show(struct seq_file *m, void *v)
>  		seq_printf(m, "\nImplementation time: [%lld, %ld]\n",
>  			clp->cl_nii_time.tv_sec, clp->cl_nii_time.tv_nsec);
>  	}
> +	seq_printf(m, "callback state: %s\n", cb_state2str(clp->cl_cb_state));
> +	seq_printf(m, "callback address: %pISpc\n", &clp->cl_cb_conn.cb_addr);
>  	drop_client(clp);
>  
>  	return 0;
> diff --git a/fs/nfsd/trace.c b/fs/nfsd/trace.c
> index f008b95ceec2..6291b5d10824 100644
> --- a/fs/nfsd/trace.c
> +++ b/fs/nfsd/trace.c
> @@ -2,3 +2,18 @@
>  
>  #define CREATE_TRACE_POINTS
>  #include "trace.h"
> +
> +const char *cb_state2str(const int state)
> +{
> +	switch (state) {
> +	case NFSD4_CB_UP:
> +		return "UP";
> +	case NFSD4_CB_UNKNOWN:
> +		return "UNKNOWN";
> +	case NFSD4_CB_DOWN:
> +		return "DOWN";
> +	case NFSD4_CB_FAULT:
> +		return "FAULT";
> +	}
> +	return "UNDEFINED";
> +}
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index 10cc3aaf1089..8908d48b2aa6 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -876,12 +876,7 @@
>  	TP_printk("client %08x:%08x", __entry->cl_boot, __entry->cl_id)
>  )
>  
> -#define show_cb_state(val)						\
> -	__print_symbolic(val,						\
> -		{ NFSD4_CB_UP,		"UP" },				\
> -		{ NFSD4_CB_UNKNOWN,	"UNKNOWN" },			\
> -		{ NFSD4_CB_DOWN,	"DOWN" },			\
> -		{ NFSD4_CB_FAULT,	"FAULT"})
> +const char *cb_state2str(const int state);
>  
>  DECLARE_EVENT_CLASS(nfsd_cb_class,
>  	TP_PROTO(const struct nfs4_client *clp),
> @@ -901,7 +896,7 @@
>  	),
>  	TP_printk("addr=%pISpc client %08x:%08x state=%s",
>  		__entry->addr, __entry->cl_boot, __entry->cl_id,
> -		show_cb_state(__entry->state))
> +		cb_state2str(__entry->state))
>  );
>  
>  #define DEFINE_NFSD_CB_EVENT(name)			\
> -- 
> 1.8.3.1