cfdisk will happily create a partition of size zero

cfdisk will happily create a partition of size zero

[Benno Schulenberg]

Hi,

My disk is configured like this:

                                 Disk: /dev/sda
             Size: 149.1 GiB, 160041885696 bytes, 312581808 sectors
                       Label: dos, identifier: 0x5ef35ef3

    Device      Boot     Start       End   Sectors   Size Id Type
    /dev/sda1             2048  31262489  31260442  14.9G 83 Linux
    /dev/sda2   *     31262490  62508914  31246425  14.9G 83 Linux
    /dev/sda3         62508915  93755339  31246425  14.9G 83 Linux
    /dev/sda4         93755401 312576704 218821304 104.4G  5 Extended           
    |-/dev/sda5       93755403  94767434   1012032 494.2M 82 Linux swap / Solari
    |-/dev/sda6       94767498 252975554 158208057  75.5G 83 Linux
    |-/dev/sda7      252975618 282776129  29800512  14.2G 83 Linux
    `-/dev/sda8      282776193 312576704  29800512  14.2G 83 Linux
    Free space       312578048 312581807      3760   1.9M

When I delete sda5 to sda8 and then sda4, and then recreate sda4,
and then in the free space create a partition of 1 sector, things
look like this:

    /dev/sda4               93755392  312581807  218826416  104.4G   5 Extended
    |-/dev/sda5             93757440   93757440          0      0B  83 Linux    
    `-Free space            93759488  312581807  218822320  104.4G

Strange.  Start and end of sda5 are on the same sector?

Anyway, if I then in the free space try to create a partition of
say 123M, the response on the bottombar is (in red):

Start sector 93759488 out of range.

??

Benno

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Re: cfdisk will happily create a partition of size zero

[Phillip Susi]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

On 1/31/2015 4:58 AM, Benno Schulenberg wrote:
> /dev/sda4               93755392  312581807  218826416  104.4G   5
> Extended |-/dev/sda5             93757440   93757440          0
> 0B  83 Linux `-Free space            93759488  312581807  218822320
> 104.4G
> 
> Strange.  Start and end of sda5 are on the same sector?

Looks like there is also an off by one error in the size calculation
since a partition that starts and ends on the same sector does still
occupy that one sector, so its size can not be zero.


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Re: cfdisk will happily create a partition of size zero

[Karel Zak]

On Thu, Feb 05, 2015 at 02:59:42PM -0500, Phillip Susi wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> On 1/31/2015 4:58 AM, Benno Schulenberg wrote:
> > /dev/sda4               93755392  312581807  218826416  104.4G   5
> > Extended |-/dev/sda5             93757440   93757440          0
> > 0B  83 Linux `-Free space            93759488  312581807  218822320
> > 104.4G
> > 
> > Strange.  Start and end of sda5 are on the same sector?
> 
> Looks like there is also an off by one error in the size calculation
> since a partition that starts and ends on the same sector does still
> occupy that one sector, so its size can not be zero.

It was core of the problem -), all this should be already fixed. Try it.

    Karel

-- 
 Karel Zak  <kzak@redhat.com>
 http://karelzak.blogspot.com