Re: [Qemu-devel] [PATCH 03/32] vvfat: Fix partition table

[Kevin Wolf <kwolf@redhat.com>]

Am 05.07.2012 13:10, schrieb Markus Armbruster:
> Kevin Wolf <kwolf@redhat.com> writes:
> 
>> Am 05.07.2012 11:23, schrieb Markus Armbruster:
>>> Kevin Wolf <kwolf@redhat.com> writes:
>>>
>>>> Am 29.06.2012 22:33, schrieb Blue Swirl:
>>>>> On Fri, Jun 29, 2012 at 3:34 PM, Markus Armbruster <armbru@redhat.com> wrote:
>>>>>> +    partition->length_sector_long = cpu_to_le32(s->bs->total_sectors
>>>>>> +                                                - s->first_sectors_number + 1);
>>>>
>>>> Just wondering... This should be the same as s->sector_count, right?
>>>
>>> Hmm.  vvfat_open() assigns:
>>>
>>>     s->sector_count = cyls * heads * secs - (s->first_sectors_number - 1);
>>>     bs->total_sectors = cyls * heads * secs;
>>>
>>> But it then changes it minds and does:
>>>
>>>     s->sector_count = s->faked_sectors + s->sectors_per_cluster*s->cluster_count;
>>
>> Which probably means that they differ if some sub-cluster sized space is
>> left unused at the end of the disk. It's not useful to have this space
>> included in the partition, but it doesn't hurt either. So I suppose
>> either way is fine.
> 
> Complication: the partition should end on a cylinder boundary.  Shaving
> off an unused tail may well interfere with that.  Let's stick to v1
> here.

Good point. If anything, maybe add a comment.

Kevin