Re: [dm-devel] block mapping

["Kasatkin, Dmitry" <dmitry kasatkin intel com>]

On Thu, Sep 29, 2011 at 5:19 PM, Zdenek Kabelac <zkabelac redhat com> wrote:
> Dne 29.9.2011 16:10, Kasatkin, Dmitry napsal(a):
>> Hello,
>>
>>
>> On Thu, Sep 29, 2011 at 4:42 PM, Zdenek Kabelac <zkabelac redhat com> wrote:
>>> Dne 29.9.2011 15:35, Kasatkin, Dmitry napsal(a):
>>>> Hello All,
>>>>
>>>> I would like to implement such block device, which can store
>>>> additional information along with the block data.
>>>> For example. so if file system has 4k block, I would like to store
>>>> 4k+256b of additional information...
>>>>
>>>> Can such block device be implemented with device mapper?
>>>>
>>>
>>> Yes - i.e.the old snapshot target stores the block and it's remapping info
>>> (thought the size info is much smaller then 256b)
>>>
>>
>> 1. Old snapshot target? Where is it...
>>
>
> kernel/drivers/md/dm-snap-persistent.c
>
>
>> 2. Isn't it stores some data at the beginning of the block device - in
>> the header..
>
> A bit more complicated that this - but yes, quite straightforward target.
>

Thanks

>
> Zdenek
>
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