Re: junk in MBR editor and uneditable partition

[David Laight <david%l8s.co.uk@localhost>]

On Fri, Jun 27, 2008 at 05:43:53PM -0500, Jeremy C. Reed wrote:
> Probably can't easily reproduce this, but I will mention it anyways.
> 
> My disk had a mix of DOS, NTFS, Linux and NetBSD partitions.
> 
> sysinst from latest amd64 HEAD build (4.99.67).
> 
> MBR partition editor had junk under "Bootmenu" field:
> 
> NTFS          Error
> Linux native  'I.<            (the dot is really some high ascii corner)
> Unknown (5)   A

I don't think sysinst actually checks for the netbsd bootmenu 'magic'
before displaying the bootmenu text - so is showing whatever 'junk' is
in that section of the mbr code.
That might be considered a bug...

> I deleted partitions -- selected and then selected "type" and then chose 
> to delete.
> 
> But couldn't delete the "Unknown (5)". No way to select the "type". Also 
> couldn't change its size less than 30000 MB.
> 
> So went to shell and ran "fdisk -u wd0"
> 
> Said it was "Extended partition" (even though I had another regular 
> partition following it).

The is no requirement for the extended partition to be in the last slot.

Type '5' is one of the 'extended partition' types, but not the one that
is usually used (5 is MBR_PTYPE_EXT, more normal is 0x0f MBR_PTYPE_EXT_LBA).
The code is probably confused because it expects to find the same
data structes as for the 0x0f - and they clearly aren't present!

> I set type to 0 and removed these. (It warned about losing extended 
> partitions.)

Sysinst is less pragmatic!

> Restarted sysinst and then could setup MBR partitions.
> 
> Should I file a PR for this?

They are 2 unrelated issues - so would need separate bugs.
However the 2nd one is unlikely to be investigated (by anyone) without
a means of creating an equivalent mbr. So a hexdump of sector 0, and the
first sector of the type '5' ptn - and maybe an indication of what had
actually created it.

>   Jeremy C. Reed


        David

-- 
David Laight: david%l8s.co.uk@localhost