Re: [PATCH] NFSD: Fix trace_nfsd_slot_seqid_sequence

[Jeff Layton <jlayton@kernel.org>]

On Mon, 2025-02-03 at 09:49 -0500, cel@kernel.org wrote:
> From: Chuck Lever <chuck.lever@oracle.com>
> 
> While running down the problem triggered by disconnect injection,
> I noticed the "in use" string was actually never hooked up in this
> trace point, so it always showed the traced slot as not in use. But
> what might be more useful is showing all the slot status flags.
> 
> Also, this trace point can record and report the slot's index
> number, which among other things is useful for troubleshooting slot
> table expansion and contraction.
> 
> Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
> ---
>  fs/nfsd/trace.h | 19 +++++++++++++++----
>  1 file changed, 15 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
> index ad2c0c432d08..49bbd26ffcdb 100644
> --- a/fs/nfsd/trace.h
> +++ b/fs/nfsd/trace.h
> @@ -803,6 +803,14 @@ DEFINE_EVENT(nfsd_cs_slot_class, nfsd_##name, \
>  DEFINE_CS_SLOT_EVENT(slot_seqid_conf);
>  DEFINE_CS_SLOT_EVENT(slot_seqid_unconf);
>  
> +#define show_nfs_slot_flags(val)					\
> +	__print_flags(val, "|",						\
> +		{ NFSD4_SLOT_INUSE,		"INUSE" },		\
> +		{ NFSD4_SLOT_CACHETHIS,		"CACHETHIS" },		\
> +		{ NFSD4_SLOT_INITIALIZED,	"INITIALIZED" },	\
> +		{ NFSD4_SLOT_CACHED,		"CACHED" },		\
> +		{ NFSD4_SLOT_REUSED,		"REUSED" })
> +
>  TRACE_EVENT(nfsd_slot_seqid_sequence,
>  	TP_PROTO(
>  		const struct nfs4_client *clp,
> @@ -813,10 +821,11 @@ TRACE_EVENT(nfsd_slot_seqid_sequence,
>  	TP_STRUCT__entry(
>  		__field(u32, seqid)
>  		__field(u32, slot_seqid)
> +		__field(u32, slot_index)
> +		__field(unsigned long, slot_flags)
>  		__field(u32, cl_boot)
>  		__field(u32, cl_id)
>  		__sockaddr(addr, clp->cl_cb_conn.cb_addrlen)
> -		__field(bool, in_use)
>  	),
>  	TP_fast_assign(
>  		__entry->cl_boot = clp->cl_clientid.cl_boot;
> @@ -825,11 +834,13 @@ TRACE_EVENT(nfsd_slot_seqid_sequence,
>  				  clp->cl_cb_conn.cb_addrlen);
>  		__entry->seqid = seq->seqid;
>  		__entry->slot_seqid = slot->sl_seqid;
> +		__entry->slot_index = seq->slotid;
> +		__entry->slot_flags = slot->sl_flags;
>  	),
> -	TP_printk("addr=%pISpc client %08x:%08x seqid=%u slot_seqid=%u (%sin use)",
> +	TP_printk("addr=%pISpc client %08x:%08x idx=%u seqid=%u slot_seqid=%u flags=%s",
>  		__get_sockaddr(addr), __entry->cl_boot, __entry->cl_id,
> -		__entry->seqid, __entry->slot_seqid,
> -		__entry->in_use ? "" : "not "
> +		__entry->slot_index, __entry->seqid, __entry->slot_seqid,
> +		show_nfs_slot_flags(__entry->slot_flags)
>  	)
>  );
>  

Reviewed-by: Jeff Layton <jlayton@kernel.org>