Used space is hardly freed when a file is deleted and CopyTo is called

[starius]

I put files of sizes 180M and 10M to a GKV store. The size of storage file was 250M.
Then I removed a file of size 180M and called CopyTo. New storage file is 200M.

[starius]

The following workaround fixed most of the leaks for me: set file size to 0 before removing it.

diff --git a/dir.go b/dir.go
index 32109ba..7ccc1e6 100644
--- a/dir.go
+++ b/dir.go
@@ -153,6 +153,7 @@ func (dir *Dir) Remove(ctx context.Context, req *fuse.RemoveRequest) error {
        }
 
        if !isDir {
+               node.(*File).setSize(0)
                dir.Files = append(dir.Files[:posn], dir.Files[posn+1:]...)
                dir.MarkDirty()
                err = dir.WriteBlock(dir, dir.KVS)

But some leaks must be still active: after I copied the store to another file, its size was 40K.