From 45465e5a054f638aeae1ef1c9ed246c931a8376b Mon Sep 17 00:00:00 2001
From: Neetika Mittal <7251919+mneetika@users.noreply.github.com>
Date: Tue, 2 Jun 2026 04:33:37 +0100
Subject: [PATCH] fix(master): notify clients after manual volume grow (#9656)

Co-authored-by: Neetika Mittal <mneetika@users.noreply.github.com>
---
 weed/server/master_grpc_server.go           |  7 ++++
 weed/server/master_grpc_server_test.go      | 37 +++++++++++++++++++++
 weed/server/master_grpc_server_volume.go    |  4 +--
 weed/server/master_server_handlers_admin.go |  3 ++
 4 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/weed/server/master_grpc_server.go b/weed/server/master_grpc_server.go
index aef686959..33c1ec37c 100644
--- a/weed/server/master_grpc_server.go
+++ b/weed/server/master_grpc_server.go
@@ -427,6 +427,13 @@ func (ms *MasterServer) broadcastToClients(message *master_pb.KeepConnectedRespo
 	ms.clientChansLock.RUnlock()
 }
 
+// broadcastVolumeLocationsToClients notifies connected clients about newly created volume locations.
+func (ms *MasterServer) broadcastVolumeLocationsToClients(locations []*master_pb.VolumeLocation) {
+	for _, location := range locations {
+		ms.broadcastToClients(&master_pb.KeepConnectedResponse{VolumeLocation: location})
+	}
+}
+
 func (ms *MasterServer) informNewLeader(stream master_pb.Seaweed_KeepConnectedServer) error {
 	leader, err := ms.Topo.Leader()
 	if err != nil {
diff --git a/weed/server/master_grpc_server_test.go b/weed/server/master_grpc_server_test.go
index 4c085436f..fb12f5dc9 100644
--- a/weed/server/master_grpc_server_test.go
+++ b/weed/server/master_grpc_server_test.go
@@ -2,8 +2,10 @@ package weed_server
 
 import (
 	"testing"
+	"time"
 
 	"github.com/seaweedfs/seaweedfs/weed/cluster"
+	"github.com/seaweedfs/seaweedfs/weed/pb/master_pb"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -35,3 +37,38 @@ func TestInitialLockRingUpdateSkipsNonFilers(t *testing.T) {
 
 	assert.Nil(t, ms.initialLockRingUpdate(cluster.BrokerType, "group-a"))
 }
+
+// TestBroadcastVolumeLocationsToClients verifies grown volume locations are sent to registered clients.
+func TestBroadcastVolumeLocationsToClients(t *testing.T) {
+	clientChan := make(chan *master_pb.KeepConnectedResponse, 2)
+	ms := &MasterServer{
+		clientChans: map[string]chan *master_pb.KeepConnectedResponse{
+			"default.filer@127.0.0.1:8888": clientChan,
+		},
+	}
+
+	ms.broadcastVolumeLocationsToClients([]*master_pb.VolumeLocation{
+		{Url: "volume-a:8080", NewVids: []uint32{7}},
+		{Url: "volume-b:8080", NewVids: []uint32{8}},
+	})
+
+	var first *master_pb.KeepConnectedResponse
+	select {
+	case first = <-clientChan:
+	case <-time.After(2 * time.Second):
+		t.Fatal("timed out waiting for first broadcast")
+	}
+	require.NotNil(t, first.GetVolumeLocation())
+	assert.Equal(t, []uint32{7}, first.GetVolumeLocation().GetNewVids())
+	assert.Equal(t, "volume-a:8080", first.GetVolumeLocation().GetUrl())
+
+	var second *master_pb.KeepConnectedResponse
+	select {
+	case second = <-clientChan:
+	case <-time.After(2 * time.Second):
+		t.Fatal("timed out waiting for second broadcast")
+	}
+	require.NotNil(t, second.GetVolumeLocation())
+	assert.Equal(t, []uint32{8}, second.GetVolumeLocation().GetNewVids())
+	assert.Equal(t, "volume-b:8080", second.GetVolumeLocation().GetUrl())
+}
diff --git a/weed/server/master_grpc_server_volume.go b/weed/server/master_grpc_server_volume.go
index 586bf37f4..fbffea562 100644
--- a/weed/server/master_grpc_server_volume.go
+++ b/weed/server/master_grpc_server_volume.go
@@ -42,9 +42,7 @@ func (ms *MasterServer) DoAutomaticVolumeGrow(req *topology.VolumeGrowRequest) {
 		glog.V(1).Infof("automatic volume grow failed: %+v", err)
 		return
 	}
-	for _, newVidLocation := range newVidLocations {
-		ms.broadcastToClients(&master_pb.KeepConnectedResponse{VolumeLocation: newVidLocation})
-	}
+	ms.broadcastVolumeLocationsToClients(newVidLocations)
 }
 
 func (ms *MasterServer) ProcessGrowRequest() {
diff --git a/weed/server/master_server_handlers_admin.go b/weed/server/master_server_handlers_admin.go
index 322a41608..76e4ebc59 100644
--- a/weed/server/master_server_handlers_admin.go
+++ b/weed/server/master_server_handlers_admin.go
@@ -91,6 +91,9 @@ func (ms *MasterServer) volumeGrowHandler(w http.ResponseWriter, r *http.Request
 		} else {
 			var newVidLocations []*master_pb.VolumeLocation
 			newVidLocations, err = ms.vg.GrowByCountAndType(ms.grpcDialOption, uint32(count), option, ms.Topo)
+			if len(newVidLocations) > 0 {
+				ms.broadcastVolumeLocationsToClients(newVidLocations)
+			}
 			count = uint64(len(newVidLocations))
 		}
 	} else {