if param count changes we need to zero the file size
@ -56,6 +56,7 @@ int AP_Filesystem_Param::open(const char *fname, int flags)
r.start = 0;
r.count = 0;
r.read_size = 0;
r.file_size = 0;
r.writebuf = nullptr;
if (!read_only) {
// setup for upload