NFSD: Move nfsd_file_trace_alloc() tracepoint

Avoid recording the allocation of an nfsd_file item that is
immediately released because a matching item was already
inserted in the hash.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/filecache.c

@@ -303,7 +303,6 @@ nfsd_file_alloc(struct nfsd_file_lookup_key *key, unsigned int may)
 		refcount_set(&nf->nf_ref, 2);
 		nf->nf_may = key->need;
 		nf->nf_mark = NULL;
-		trace_nfsd_file_alloc(nf);
 	}
 	return nf;
 }
@@ -1126,6 +1125,7 @@ out_status:
 	return status;
 
 open_file:
+	trace_nfsd_file_alloc(nf);
 	nf->nf_mark = nfsd_file_mark_find_or_create(nf);
 	if (nf->nf_mark) {
 		if (open) {

fs/nfsd/trace.h

@@ -774,12 +774,35 @@ DEFINE_EVENT(nfsd_file_class, name, \
 	TP_PROTO(struct nfsd_file *nf), \
 	TP_ARGS(nf))
 
-DEFINE_NFSD_FILE_EVENT(nfsd_file_alloc);
 DEFINE_NFSD_FILE_EVENT(nfsd_file_put_final);
 DEFINE_NFSD_FILE_EVENT(nfsd_file_unhash);
 DEFINE_NFSD_FILE_EVENT(nfsd_file_put);
 DEFINE_NFSD_FILE_EVENT(nfsd_file_unhash_and_dispose);
 
+TRACE_EVENT(nfsd_file_alloc,
+	TP_PROTO(
+		const struct nfsd_file *nf
+	),
+	TP_ARGS(nf),
+	TP_STRUCT__entry(
+		__field(const void *, nf_inode)
+		__field(unsigned long, nf_flags)
+		__field(unsigned long, nf_may)
+		__field(unsigned int, nf_ref)
+	),
+	TP_fast_assign(
+		__entry->nf_inode = nf->nf_inode;
+		__entry->nf_flags = nf->nf_flags;
+		__entry->nf_ref = refcount_read(&nf->nf_ref);
+		__entry->nf_may = nf->nf_may;
+	),
+	TP_printk("inode=%p ref=%u flags=%s may=%s",
+		__entry->nf_inode, __entry->nf_ref,
+		show_nf_flags(__entry->nf_flags),
+		show_nfsd_may_flags(__entry->nf_may)
+	)
+);
+
 TRACE_EVENT(nfsd_file_acquire,
 	TP_PROTO(
 		const struct svc_rqst *rqstp,