Re: [PATCH] nested partitions

[Vladimir 'phcoder' Serbinenko]

Rediff

On Mon, Aug 24, 2009 at 12:57 AM, Vladimir 'phcoder'
Serbinenko<address@hidden> wrote:
> Rediff
> On Mon, Aug 17, 2009 at 4:34 PM, Vladimir 'phcoder'
> Serbinenko<address@hidden> wrote:
>> On Mon, Aug 17, 2009 at 4:06 PM, Robert Millan<address@hidden> wrote:
>>> On Mon, Aug 17, 2009 at 03:00:52PM +0200, Vladimir 'phcoder' Serbinenko 
>>> wrote:
>>>> Rediff and few fixes
>>>
>>> Please note that after what we discussed on IRC, we need to find a solution
>>> that wouldn't make boot time increase linearly with the number of 
>>> filesystems
>>> or partmaps GRUB supports.
>>>
>> It probe time scales linearly no matter what we do. Fortunately with
>> disk cache few first sectors are read and checked for different
>> signatures which is fast. As for module autoload with search patch it
>> doesn't happen except in the failure to access requested device.
>>> I really think supporting every sort of combination is too extreme.  For
>>> example who would want an msdos/msdos chain?  OpenSolaris creates one, but
>>> it's a false positive.
>>>
>> minix does it and it's not a false positive.
>>> The overall idea *is* nice.  Some combinations (e.g. msdos/bsd) are cleaner
>>> this way, but supporting everything doesn't scale well.
>> AFAIK no partmap goes beyond first 16K for signature checking. Time
>> for signature checking can be neglected and 16K would be read for
>> filesystem probe too. Additionally e.g. (hd0,1) is probed for
>> subpartitions only if (hd0,1,X) is requested or we're scanning through
>> partitions. In last case we're likely to fsprobe partition anyway so
>> it doesn't create any overhead
>>>
>>> Perhaps we can explicitly list which combinations make sense?  So when an
>>> msdos label is found, its partitions are probed for bsd labels too, but not
>>> for msdos labels again, etc.
>>>
>>> --
>>> Robert Millan
>>>
>>>  The DRM opt-in fallacy: "Your data belongs to us. We will decide when (and
>>>  how) you may access your data; but nobody's threatening your freedom: we
>>>  still allow you to remove your data and not access it at all."
>>>
>>>
>>> _______________________________________________
>>> Grub-devel mailing list
>>> address@hidden
>>> http://lists.gnu.org/mailman/listinfo/grub-devel
>>>
>>
>>
>>
>> --
>> Regards
>> Vladimir 'phcoder' Serbinenko
>>
>> Personal git repository: http://repo.or.cz/w/grub2/phcoder.git
>>
>
>
>
> --
> Regards
> Vladimir 'phcoder' Serbinenko
>
> Personal git repository: http://repo.or.cz/w/grub2/phcoder.git
>



-- 
Regards
Vladimir 'phcoder' Serbinenko

Personal git repository: http://repo.or.cz/w/grub2/phcoder.git

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