refactoring: separating .vif from tier file loading

weed/storage/volume.go

@@ -27,6 +27,7 @@ type Volume struct {
 	needleMapKind      NeedleMapType
 	noWriteOrDelete    bool // if readonly, either noWriteOrDelete or noWriteCanDelete
 	noWriteCanDelete   bool // if readonly, either noWriteOrDelete or noWriteCanDelete
+	hasRemoteFile      bool // if the volume has a remote file
 	MemoryMapMaxSizeMb uint32
 
 	super_block.SuperBlock

weed/storage/volume_loading.go

@@ -26,9 +26,13 @@ func (v *Volume) load(alsoLoadIndex bool, createDatIfMissing bool, needleMapKind
 	fileName := v.FileName()
 	alreadyHasSuperBlock := false
 
-	if v.maybeLoadVolumeInfo() {
+	v.maybeLoadVolumeInfo()
+
+	if v.HasRemoteFile() {
 		v.noWriteCanDelete = true
-		// open remote file
+		v.noWriteOrDelete = false
+		glog.V(0).Infof("loading volume %d from remote %v", v.Id, v.volumeInfo.Files)
+		v.LoadRemoteFile()
 		alreadyHasSuperBlock = true
 	} else if exists, canRead, canWrite, modifiedTime, fileSize := checkFile(fileName + ".dat"); exists {
 		// open dat file

weed/storage/volume_tier.go

@@ -7,10 +7,11 @@ import (
 
 	_ "github.com/chrislusf/seaweedfs/weed/storage/backend/s3_backend"
 
+	"github.com/golang/protobuf/jsonpb"
+
 	"github.com/chrislusf/seaweedfs/weed/glog"
 	"github.com/chrislusf/seaweedfs/weed/pb/volume_server_pb"
 	"github.com/chrislusf/seaweedfs/weed/storage/backend"
-	"github.com/golang/protobuf/jsonpb"
 )
 
 func (v *Volume) GetVolumeInfo() *volume_server_pb.VolumeInfo {
@@ -57,21 +58,13 @@ func (v *Volume) maybeLoadVolumeInfo() bool {
 	glog.V(0).Infof("volume %d is tiered to %s as %s and read only", v.Id,
 		v.volumeInfo.Files[0].BackendName(), v.volumeInfo.Files[0].Key)
 
-	v.noWriteCanDelete = true
-	v.noWriteOrDelete = false
-
-	glog.V(0).Infof("loading volume %d from remote %v", v.Id, v.volumeInfo.Files)
-	v.LoadRemoteFile()
+	v.hasRemoteFile = true
 
 	return true
 }
 
 func (v *Volume) HasRemoteFile() bool {
-	if v.DataBackend == nil {
-		return false
-	}
-	_, ok := v.DataBackend.(*backend.DiskFile)
-	return !ok
+	return v.hasRemoteFile
 }
 
 func (v *Volume) LoadRemoteFile() error {