fix: refactor locks to apply them uniquely per node (#11052)

This refactor is done for few reasons below

- to avoid deadlocks in scenarios when number
  of nodes are smaller < actual erasure stripe
  count where in N participating local lockers
  can lead to deadlocks across systems.

- avoids expiry routines to run 1000 of separate
  network operations and routes per disk where
  as each of them are still accessing one single
  local entity.

- it is ideal to have since globalLockServer
  per instance.

- In a 32node deployment however, each server
  group is still concentrated towards the
  same set of lockers that partipicate during
  the write/read phase, unlike previous minio/dsync
  implementation - this potentially avoids send
  32 requests instead we will still send at max
  requests of unique nodes participating in a
  write/read phase.

- reduces overall chattiness on smaller setups.

cmd/lock-rest-client.go

@@ -32,7 +32,7 @@ import (
 // lockRESTClient is authenticable lock REST client
 type lockRESTClient struct {
 	restClient *rest.Client
-	endpoint   Endpoint
+	u          *url.URL
 }
 
 func toLockError(err error) error {
@@ -51,7 +51,7 @@ func toLockError(err error) error {
 
 // String stringer *dsync.NetLocker* interface compatible method.
 func (client *lockRESTClient) String() string {
-	return client.endpoint.String()
+	return client.u.String()
 }
 
 // Wrapper to restClient.Call to handle network errors, in case of network error the connection is marked disconnected
@@ -137,7 +137,7 @@ func (client *lockRESTClient) Expired(ctx context.Context, args dsync.LockArgs)
 
 func newLockAPI(endpoint Endpoint) dsync.NetLocker {
 	if endpoint.IsLocal {
-		return globalLockServers[endpoint]
+		return globalLockServer
 	}
 	return newlockRESTClient(endpoint)
 }
@@ -147,7 +147,7 @@ func newlockRESTClient(endpoint Endpoint) *lockRESTClient {
 	serverURL := &url.URL{
 		Scheme: endpoint.Scheme,
 		Host:   endpoint.Host,
-		Path:   pathJoin(lockRESTPrefix, endpoint.Path, lockRESTVersion),
+		Path:   pathJoin(lockRESTPrefix, lockRESTVersion),
 	}
 
 	restClient := rest.NewClient(serverURL, globalInternodeTransport, newAuthToken)
@@ -163,5 +163,8 @@ func newlockRESTClient(endpoint Endpoint) *lockRESTClient {
 		return !isNetworkError(err)
 	}
 
-	return &lockRESTClient{endpoint: endpoint, restClient: restClient}
+	return &lockRESTClient{u: &url.URL{
+		Scheme: endpoint.Scheme,
+		Host:   endpoint.Host,
+	}, restClient: restClient}
 }