Getting a block from a block device?

[Manish Katiyar]

On Tue, Nov 8, 2011 at 6:02 AM, Dan Luedtke <maildanrl at googlemail.com> wrote:
> Thanks for all the answers!
>
>> You need to look at other block-based file systems in the kernel sources in fs dir for examples and understand how they do it.
> I looked at fs/minix/* fs/fat/* and peeked into fs/ext2/, but got more
> confused so I decided to ask for a starting point.

Hi Dan,

You may find https://github.com/mkatiyar/testfs helpful.

>
>> Also i think if you are interested in reading the first sector
>> then you can probably check the block/genhd.c file
>> get the disk (i.e struct genhd) then the partition (struct hdpart)
>> you will be able to get the first sector.
> Thanks, a well documented source file. However, shouldn't I get the
> right partition (I called it block device in previously sent mails,
> thought of e.g. /dev/sda2 as a device not a partition) from VFS when a
> user requestes mounting it?
>
>> That's an old assignment from my uni.
> Wow, exactly what I needed! Thanks for this starting point.
>
>> I would redirect you to learn about struct gendisk and struct bio.
> Noted, I will take a look after studying the vvfs-files from Stephens link.
>
>> Can you tell what are you trying to achieve?
> I'd like to implement a filesystem as kernel modul (like fat, ext2,
> ...). The filesystem is a very simple one, based on chained blocks
> (similar to linked lists in c). I "invented" it when I tried to write
> a bootloader that does not require a second stage to read an kernel
> image. (This is all more or less a "because we can"-project, no
> commercial background, just learning).
>
> Once again, thank you guys!
>
> Greetings,
>
> Dan
> --
> Dan Luedtke
> http://www.danrl.de
>
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-- 
Thanks -
Manish