ensure metadata follow a specific folder

fix https://github.com/seaweedfs/seaweedfs/issues/5774

weed/mount/meta_cache/meta_cache_subscribe.go

@@ -7,6 +7,7 @@ import (
 	"github.com/seaweedfs/seaweedfs/weed/pb"
 	"github.com/seaweedfs/seaweedfs/weed/pb/filer_pb"
 	"github.com/seaweedfs/seaweedfs/weed/util"
+	"strings"
 )
 
 func SubscribeMetaEvents(mc *MetaCache, selfSignature int32, client filer_pb.FilerClient, dir string, lastTsNs int64) error {
@@ -57,12 +58,17 @@ func SubscribeMetaEvents(mc *MetaCache, selfSignature int32, client filer_pb.Fil
 
 	}
 
+	prefix := dir
+	if !strings.HasSuffix(prefix, "/") {
+		prefix = prefix + "/"
+	}
+
 	metadataFollowOption := &pb.MetadataFollowOption{
 		ClientName:             "mount",
 		ClientId:               selfSignature,
 		ClientEpoch:            1,
 		SelfSignature:          selfSignature,
-		PathPrefix:             dir,
+		PathPrefix:             prefix,
 		AdditionalPathPrefixes: nil,
 		DirectoriesToWatch:     nil,
 		StartTsNs:              lastTsNs,