fix bug that gen layer tar contains duplicated files

Signed-off-by: frankyang <[email protected]>

cache/blobs_linux.go

@@ -43,8 +43,17 @@ func (sr *immutableRef) tryComputeOverlayBlob(ctx context.Context, lower, upper
  if err != nil {
  return emptyDesc, false, errors.Wrap(err, "failed to open writer")
  }
+ cw.Truncate(0)
  defer func() {
  if cw != nil {
+ // after commit success cw will be set to nil, if cw isn't nil, error
+ // happened before commit, we should abort this ingest, and because the
+ // error may incured by ctx cancel, use a new context here. And since
+ // cm.Close will unlock this ref in the content store, we invoke abort
+ // to remove the ingest root in advance.
+ if aerr := sr.cm.ContentStore.Abort(context.Background(), ref); aerr != nil {
+ bklog.G(ctx).WithError(aerr).Warnf("failed to abort writer %q", ref)
+ }
  if cerr := cw.Close(); cerr != nil {
  bklog.G(ctx).WithError(cerr).Warnf("failed to close writer %q", ref)
  }