Top Locks command implementation (#7052)

API to list locks used in distributed XL mode

cmd/peer-rpc-client.go

@@ -1,5 +1,5 @@
 /*
- * Minio Cloud Storage, (C) 2018 Minio, Inc.
+ * Minio Cloud Storage, (C) 2018, 2019 Minio, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -200,6 +200,15 @@ func (rpcClient *PeerRPCClient) ServerInfo() (ServerInfoData, error) {
 	return reply, err
 }
 
+// GetLocksResp stores various info from the client for each lock that is requested.
+type GetLocksResp map[string][]lockRequesterInfo
+
+// GetLocks - returns the lock information on the server to which the RPC call is made.
+func (rpcClient *PeerRPCClient) GetLocks() (resp GetLocksResp, err error) {
+	err = rpcClient.Call(peerServiceName+".GetLocks", &AuthArgs{}, &resp)
+	return resp, err
+}
+
 // NewPeerRPCClient - returns new peer RPC client.
 func NewPeerRPCClient(host *xnet.Host) (*PeerRPCClient, error) {
 	scheme := "http"