[PATCH] mkfs: Fix input offset counting in headerball mode

[Mike Baynton]

Thanks for the update, Gao! Appreciate your review.

Mike

On Fri, Oct 25, 2024 at 8:36 PM Gao Xiang <hsiangkao at linux.alibaba.com> wrote:
>
> Hi Mike,
>
> On 2024/10/25 03:58, Mike Baynton wrote:
> > When using --tar=headerball, most files included in the headerball are
> > not included in the EROFS image. mkfs.erofs typically exits prematurely,
> > having processed non-USTAR blocks as USTAR and believing they are
> > end-of-archive markers. (Other failure modes are probably also possible
> > if the input stream doesn't look like end-of-archive markers at the
> > locations that are being read.)
> >
> > This is because we lost correct count of bytes that are read from the
> > input stream when in headerball (or ddtaridx) modes. We were assuming that
> > in these modes no data would be read following the ustar block, but in
> > case of things like PAX headers, lots more data may be read without
> > incrementing tar->offset.
> >
> > This corrects by always incrementing the offset counter, and then
> > decrementing it again in the one case where headerballs differ -
> > regular file data blocks are not present.
> >
> > Signed-off-by: Mike Baynton <mike at mbaynton.com>
>
> Sorry for late reply, I'm busy in personal stuffs now.
> I will look into these cases and reply again later.
>
> Thanks,
> Gao Xiang