nfsd: Add tracepoints for update of the expkey and export cache entries

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/nfsd/export.c

@@ -141,7 +141,9 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
 	if (len == 0) {
 		set_bit(CACHE_NEGATIVE, &key.h.flags);
 		ek = svc_expkey_update(cd, &key, ek);
-		if (!ek)
+		if (ek)
+			trace_nfsd_expkey_update(ek, NULL);
+		else
 			err = -ENOMEM;
 	} else {
 		err = kern_path(buf, 0, &key.ek_path);
@@ -151,7 +153,9 @@ static int expkey_parse(struct cache_detail *cd, char *mesg, int mlen)
 		dprintk("Found the path %s\n", buf);
 
 		ek = svc_expkey_update(cd, &key, ek);
-		if (!ek)
+		if (ek)
+			trace_nfsd_expkey_update(ek, buf);
+		else
 			err = -ENOMEM;
 		path_put(&key.ek_path);
 	}
@@ -644,15 +648,17 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 	}
 
 	expp = svc_export_lookup(&exp);
-	if (expp)
-		expp = svc_export_update(&exp, expp);
-	else
+	if (!expp) {
 		err = -ENOMEM;
-	cache_flush();
-	if (expp == NULL)
-		err = -ENOMEM;
-	else
+		goto out4;
+	}
+	expp = svc_export_update(&exp, expp);
+	if (expp) {
+		trace_nfsd_export_update(expp);
+		cache_flush();
 		exp_put(expp);
+	} else
+		err = -ENOMEM;
 out4:
 	nfsd4_fslocs_free(&exp.ex_fslocs);
 	kfree(exp.ex_uuid);

fs/nfsd/trace.h

@@ -105,6 +105,32 @@ TRACE_EVENT(nfsd_exp_find_key,
 	)
 );
 
+TRACE_EVENT(nfsd_expkey_update,
+	TP_PROTO(const struct svc_expkey *key, const char *exp_path),
+	TP_ARGS(key, exp_path),
+	TP_STRUCT__entry(
+		__field(int, fsidtype)
+		__array(u32, fsid, 6)
+		__string(auth_domain, key->ek_client->name)
+		__string(path, exp_path)
+		__field(bool, cache)
+	),
+	TP_fast_assign(
+		__entry->fsidtype = key->ek_fsidtype;
+		memcpy(__entry->fsid, key->ek_fsid, 4*6);
+		__assign_str(auth_domain, key->ek_client->name);
+		__assign_str(path, exp_path);
+		__entry->cache = !test_bit(CACHE_NEGATIVE, &key->h.flags);
+	),
+	TP_printk("fsid=%x::%s domain=%s path=%s cache=%s",
+		__entry->fsidtype,
+		__print_array(__entry->fsid, 6, 4),
+		__get_str(auth_domain),
+		__get_str(path),
+		__entry->cache ? "pos" : "neg"
+	)
+);
+
 TRACE_EVENT(nfsd_exp_get_by_name,
 	TP_PROTO(const struct svc_export *key,
 		 int status),
@@ -126,6 +152,26 @@ TRACE_EVENT(nfsd_exp_get_by_name,
 	)
 );
 
+TRACE_EVENT(nfsd_export_update,
+	TP_PROTO(const struct svc_export *key),
+	TP_ARGS(key),
+	TP_STRUCT__entry(
+		__string(path, key->ex_path.dentry->d_name.name)
+		__string(auth_domain, key->ex_client->name)
+		__field(bool, cache)
+	),
+	TP_fast_assign(
+		__assign_str(path, key->ex_path.dentry->d_name.name);
+		__assign_str(auth_domain, key->ex_client->name);
+		__entry->cache = !test_bit(CACHE_NEGATIVE, &key->h.flags);
+	),
+	TP_printk("path=%s domain=%s cache=%s",
+		__get_str(path),
+		__get_str(auth_domain),
+		__entry->cache ? "pos" : "neg"
+	)
+);
+
 DECLARE_EVENT_CLASS(nfsd_io_class,
 	TP_PROTO(struct svc_rqst *rqstp,
 		 struct svc_fh	*fhp,