ovl_dentry_casefolded
if (!err && ofs->casefold != ovl_dentry_casefolded(newdentry)) {
if (ofs->casefold != ovl_dentry_casefolded(base)) {
if (ofs->casefold != ovl_dentry_casefolded(this)) {
bool is_casefolded = ovl_dentry_casefolded(path->dentry);