Re: [PATCH v11 0/4] MR6855: server: Fix renaming file to a hardlink of itself.

[Jinoh Kang (＠iamahuman)]

Jinoh Kang (@iamahuman) commented about server/fd.c:
> -
>    break;
> - }
> - if (i >= 0x8000)
> - {
> -
>    set_error( STATUS_UNSUCCESSFUL );
> -
>    goto ret;
> - }
> -
> - if (!is_dir)
> - {
> -
>    /* we can't just do rename(2) here; renaming a file to its hardlink is no-op */
> -
>    if (linkat( dirfd, tmpname, dirfd, dstname, 0 ) && errno != EEXIST)
> -
>    {
> -
>        if (errno == EPERM || errno == EOPNOTSUPP)
> -
>        {
> -
>            /* FIXME: filesystem doesn't support hardlinks, entire operation might be a no-op on casefold dirs */

If a filesystem does not support hardlinks, different dentry means different file so it shouldn't be a silent no-op (for bind mounts it would return EBUSY, which is not silent)