mdconfig(8) with offset? Or: resizing a NTFS qemu image

[cpghost]

On Sat, Nov 15, 2008 at 01:46:43AM +0100, cpghost wrote:
> Hello,
> 
> I'm trying to extend a ntfs filesystem in a qemu raw image, by
> following the instructions here:
> 
> http://qemu-forum.ipi.fi/viewtopic.php?p=12362
> 
> Of course, this requires sysutils/ntfsprogs and the equivalent of
> losetup. Of course, mdconfig is our losetup.
> 
> Now, how is it possible to mdconfig a file, but starting from a
> specific offset?
> 
> (Of course, taking the image file apart, mdconfig one of its fragments,
> then putting it back together could be a hackish work-around (?), but
> it would be nice if mdconfig were able to map a partial file directly.)

Just one more data point: if I mdconfig the qemu raw image, I do
get both a /dev/md0 and /dev/md0s1 device, so I can fdisk /dev/md0s1
directly.

mdconfig to another offset in the raw image file is therefore not
strictly needed in this special case; but it would still be a
nice-to-have feature.

Regards,
-cpghost.

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