Re: [Bug-cpio] [PATCH v4 2/3] initramfs: read metadata from special file METADATA!!!

[Mimi Zohar]

Hi Roberto,

> diff --git a/init/initramfs.c b/init/initramfs.c
> index 5de396a6aac0..862c03123de8 100644
> --- a/init/initramfs.c
> +++ b/init/initramfs.c

> +static int __init do_process_metadata(char *buf, int len, bool last)
> +{

Part of the problem in upstreaming CPIO xattr support has been the
difficulty in reading and understanding the initramfs code due to a
lack of comments.  At least for any new code, let's add some comments
to simplify the review.  In this case, understanding "last", before
reading the code, would help.

Mimi

> +     int ret = 0;
> +
> +     if (!metadata_buf) {
> +             metadata_buf_ptr = metadata_buf = kmalloc(body_len, GFP_KERNEL);
> +             if (!metadata_buf_ptr) {
> +                     ret = -ENOMEM;
> +                     goto out;
> +             }
> +
> +             metadata_len = body_len;
> +     }
> +
> +     if (metadata_buf_ptr + len > metadata_buf + metadata_len) {
> +             ret = -EINVAL;
> +             goto out;
> +     }
> +
> +     memcpy(metadata_buf_ptr, buf, len);
> +     metadata_buf_ptr += len;
> +
> +     if (last)
> +             do_parse_metadata(previous_name_buf);
> +out:
> +     if (ret < 0 || last) {
> +             kfree(metadata_buf);
> +             metadata_buf = NULL;
> +             metadata = 0;
> +     }
> +
> +     return ret;
> +}
> +
>  static int __init do_copy(void)
>  {
>       if (byte_count >= body_len) {
>               if (xwrite(wfd, victim, body_len) != body_len)
>                       error("write error");
> +             if (metadata)
> +                     do_process_metadata(victim, body_len, true);
>               ksys_close(wfd);
>               do_utime(vcollected, mtime);
>               kfree(vcollected);
> @@ -458,6 +500,8 @@ static int __init do_copy(void)
>       } else {
>               if (xwrite(wfd, victim, byte_count) != byte_count)
>                       error("write error");
> +             if (metadata)
> +                     do_process_metadata(victim, byte_count, false);
>               body_len -= byte_count;
>               eat(byte_count);
>               return 1;
>