Re: [PATCH] NFSD: Fix trace_nfsd_slot_seqid_sequence

Jeff Layton
2025-02-03T15:11:44Z

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>