rm: cannot remove '.nix-portable/store/xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx-something/foo/bar': Permission denied about nix-portable HOT 3 OPEN

static void extract_archive(TarArchive & archive, const Path & destDir)
{
    int flags = ARCHIVE_EXTRACT_TIME | ARCHIVE_EXTRACT_SECURE_SYMLINKS | ARCHIVE_EXTRACT_SECURE_NODOTDOT;

    for (;;) {
        struct archive_entry * entry;
        int r = archive_read_next_header(archive.archive, &entry);
        if (r == ARCHIVE_EOF)
            break;
        auto name = archive_entry_pathname(entry);
        if (!name)
            throw Error("cannot get archive member name: %s", archive_error_string(archive.archive));
        if (r == ARCHIVE_WARN)
            warn(archive_error_string(archive.archive));
        else
            archive.check(r);

        archive_entry_copy_pathname(entry, (destDir + "/" + name).c_str());

        // sources can and do contain dirs with no rx bits
        if (archive_entry_filetype(entry) == AE_IFDIR && (archive_entry_mode(entry) & 0500) != 0500)
            archive_entry_set_mode(entry, archive_entry_mode(entry) | 0500);

        // Patch hardlink path
        const char * original_hardlink = archive_entry_hardlink(entry);
        if (original_hardlink) {
            archive_entry_copy_hardlink(entry, (destDir + "/" + original_hardlink).c_str());
        }

        archive.check(archive_read_extract(archive.archive, entry, flags));
    }

    archive.close();
}

/* To improve purity, users may want to make the Nix store a read-only
   bind mount.  So make the Nix store writable for this process. */
void LocalStore::makeStoreWritable()
{
#if __linux__
    if (!isRootUser()) return;
    /* Check if /nix/store is on a read-only mount. */
    struct statvfs stat;
    if (statvfs(realStoreDir.get().c_str(), &stat) != 0)
        throw SysError("getting info about the Nix store mount point");

    if (stat.f_flag & ST_RDONLY) {
        if (mount(0, realStoreDir.get().c_str(), "none", MS_REMOUNT | MS_BIND, 0) == -1)
            throw SysError("remounting %1% writable", realStoreDir);
    }
#endif
}