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Sender: Chuck Lever <chucklever@gmail.com>
Subject: [PATCH v2 21/27] NFSD: Add a tracepoint for DELEGRETURN
From:   Chuck Lever <chuck.lever@oracle.com>
To:     bfields@fieldses.org, Bill.Baker@oracle.com
Cc:     linux-nfs@vger.kernel.org
Date:   Mon, 21 Sep 2020 14:12:40 -0400
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Record the stateid being returned to help troubleshoot problems
with delegation. The status code is reported by the
nfsd_compound_status tracepoint.

nfsd-1035  [002]    75.873544: nfsd4_delegreturn:    xid=0x6575fc16 client 5f68de0f:f04d8b16 stateid 0000005c:00000001
nfsd-1035  [002]    75.873574: nfsd_file_put:        hash=0xac7 inode=0xffff8887050d7470 ref=1 flags=REFERENCED may=READ file=0xffff888717a79680
nfsd-1035  [002]    75.873575: nfsd_file_put_final:  hash=0xac7 inode=0xffff8887050d7470 ref=0 flags=REFERENCED may=READ file=0xffff888717a79680
nfsd-1035  [002]    75.873601: nfsd4_compoundstatus: xid=0x6575fc16 op=4/4 OP_DELEGRETURN status=OK

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 fs/nfsd/nfs4state.c |    2 ++
 fs/nfsd/trace.h     |   26 ++++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 47790c7a29a3..992ac867e52e 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -6303,6 +6303,8 @@ nfsd4_delegreturn(struct svc_rqst *rqstp, struct nfsd4_compound_state *cstate,
 	__be32 status;
 	struct nfsd_net *nn = net_generic(SVC_NET(rqstp), nfsd_net_id);
 
+	trace_nfsd4_delegreturn(rqstp, stateid);
+
 	if ((status = fh_verify(rqstp, &cstate->current_fh, S_IFREG, 0)))
 		return status;
 
diff --git a/fs/nfsd/trace.h b/fs/nfsd/trace.h
index 18b359a04d96..234b4ea7a4c7 100644
--- a/fs/nfsd/trace.h
+++ b/fs/nfsd/trace.h
@@ -679,6 +679,32 @@ TRACE_EVENT(nfsd4_stateid_prep,
 	)
 );
 
+TRACE_EVENT(nfsd4_delegreturn,
+	TP_PROTO(
+		const struct svc_rqst *rqstp,
+		const stateid_t *stp
+	),
+	TP_ARGS(rqstp, stp),
+	TP_STRUCT__entry(
+		__field(u32, xid)
+		__field(u32, cl_boot)
+		__field(u32, cl_id)
+		__field(u32, si_id)
+		__field(u32, si_generation)
+	),
+	TP_fast_assign(
+		__entry->xid = be32_to_cpu(rqstp->rq_xid);
+		__entry->cl_boot = stp->si_opaque.so_clid.cl_boot;
+		__entry->cl_id = stp->si_opaque.so_clid.cl_id;
+		__entry->si_id = stp->si_opaque.so_id;
+		__entry->si_generation = stp->si_generation;
+	),
+	TP_printk("xid=0x%08x client %08x:%08x stateid %08x:%08x",
+		__entry->xid, __entry->cl_boot, __entry->cl_id,
+		__entry->si_id, __entry->si_generation
+	)
+);
+
 DECLARE_EVENT_CLASS(nfsd_stateid_class,
 	TP_PROTO(stateid_t *stp),
 	TP_ARGS(stp),