nfsd: rename delegation related tracepoints to make them less confusing

Now when a read delegation is given, two delegation related traces
will be printed:

    nfsd_deleg_open: client 5f45b854:e6058001 stateid 00000030:00000001
    nfsd_deleg_none: client 5f45b854:e6058001 stateid 0000002f:00000001

Although the intention is to let developers know two stateid are
returned, the traces are confusing about whether or not a read delegation
is handled out. So renaming trace_nfsd_deleg_none() to trace_nfsd_open()
and trace_nfsd_deleg_open() to trace_nfsd_deleg_read() to make
the intension clearer.

The patched traces will be:

    nfsd_deleg_read: client 5f48a967:b55b21cd stateid 00000003:00000001
    nfsd_open: client 5f48a967:b55b21cd stateid 00000002:00000001
Suggested-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

fs/nfsd/nfs4state.c

@@ -5127,7 +5127,7 @@ nfs4_open_delegation(struct svc_fh *fh, struct nfsd4_open *open,
 
 	memcpy(&open->op_delegate_stateid, &dp->dl_stid.sc_stateid, sizeof(dp->dl_stid.sc_stateid));
 
-	trace_nfsd_deleg_open(&dp->dl_stid.sc_stateid);
+	trace_nfsd_deleg_read(&dp->dl_stid.sc_stateid);
 	open->op_delegate_type = NFS4_OPEN_DELEGATE_READ;
 	nfs4_put_stid(&dp->dl_stid);
 	return;
@@ -5244,7 +5244,7 @@ nfsd4_process_open2(struct svc_rqst *rqstp, struct svc_fh *current_fh, struct nf
 	nfs4_open_delegation(current_fh, open, stp);
 nodeleg:
 	status = nfs_ok;
-	trace_nfsd_deleg_none(&stp->st_stid.sc_stateid);
+	trace_nfsd_open(&stp->st_stid.sc_stateid);
 out:
 	/* 4.1 client trying to upgrade/downgrade delegation? */
 	if (open->op_delegate_type == NFS4_OPEN_DELEGATE_NONE && dp &&

fs/nfsd/trace.h

@@ -289,8 +289,8 @@ DEFINE_STATEID_EVENT(layout_recall_done);
 DEFINE_STATEID_EVENT(layout_recall_fail);
 DEFINE_STATEID_EVENT(layout_recall_release);
 
-DEFINE_STATEID_EVENT(deleg_open);
-DEFINE_STATEID_EVENT(deleg_none);
+DEFINE_STATEID_EVENT(open);
+DEFINE_STATEID_EVENT(deleg_read);
 DEFINE_STATEID_EVENT(deleg_break);
 DEFINE_STATEID_EVENT(deleg_recall);