Bug 1248115

This works for me on Fedora 22, so I guess it must have something
to do with the version of sfdisk on Debian vs Fedora (the program
was substantially rewritten upstream recently).

I have:
util-linux-2.26.2-1.fc22.x86_64

What version of sfdisk/util-linux do you have?

Sorry, I now see you're actually using Fedora host (not Debian
as I thought for some reason).  What version of util-linux is it anyway?

Same here: util-linux-2.26.2-1.fc22.x86_64

The difference may be I was extracting to an existing thin-LV so the image was resized.

Trying virt-builder with `--size 10G` option: it fails:

[root@hp-ms-01-c14 ~]# virt-builder debian-6 -o /tmp/test-debian-6 --size 10G
[   0.8] Downloading: http://libguestfs.org/download/builder/debian-6.xz
[   1.9] Planning how to build this image
[   1.9] Uncompressing
[  29.7] Resizing (using virt-resize) to expand the disk to 10.0G
virt-resize: error: libguestfs error: part_set_mbr_id: sfdisk --part-type: 
You cannot change a partition into an extended one or vice versa. Delete it 
first.
sfdisk: /dev/sdb: partition 2: failed to set partition type

If reporting bugs, run virt-resize with debugging enabled and include the 
complete output:

  virt-resize -v -x [...]

Attaching output of the same command with -x -v.

Created attachment 1057539 [details]
virt-builder output

Oh I see, I can reproduce it also using the --size 10G parameter.

This seems to be a bug in sfdisk as far as I can tell.  Here is
a reproducer:

$ rm -f disk.img 
$ truncate -s 4G disk.img
$ fdisk disk.img

Welcome to fdisk (util-linux 2.26.2).
Changes will remain in memory only, until you decide to write them.
Be careful before using the write command.

Device does not contain a recognized partition table.
Created a new DOS disklabel with disk identifier 0x81a5bda3.

Command (m for help): n
Partition type
   p   primary (0 primary, 0 extended, 4 free)
   e   extended (container for logical partitions)
Select (default p): e
Partition number (1-4, default 1): 
First sector (2048-8388607, default 2048): 
Last sector, +sectors or +size{K,M,G,T,P} (2048-8388607, default 8388607): 

Created a new partition 1 of type 'Extended' and of size 4 GiB.

Command (m for help): p
Disk disk.img: 4 GiB, 4294967296 bytes, 8388608 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x81a5bda3

Device     Boot Start     End Sectors Size Id Type
disk.img1        2048 8388607 8386560   4G  5 Extended

Command (m for help): w
The partition table has been altered.
Syncing disks.

### Notice that the MBR type byte is 05:

$ virt-filesystems -a disk.img --all --long -h
Name       Type        VFS      Label  MBR  Size  Parent
/dev/sda1  filesystem  unknown  -      -    1.0K  -
/dev/sda1  partition   -        -      05   1.0K  /dev/sda
/dev/sda   device      -        -      -    4.0G  -

### Now try setting the MBR type byte to 05.

$ sfdisk --part-type /dev/sda 1 5
You cannot change a partition into an extended one or vice versa. Delete it first.
sfdisk: /dev/sda: partition 1: failed to set partition type

Bleah; the sfdisk command there was obviously wrong.  However
it still fails when I use the correct command:

$ sfdisk --part-type disk.img 1 5
You cannot change a partition into an extended one or vice versa. Delete it first.
sfdisk: disk.img: partition 1: failed to set partition type

Fixed by upstream commit df15fb3d053716d03055df755911d66814054b4b. 
Thanks for your report!

Note that with the bugfix you still cannot change type of the extended partition which is already used by nested logical partition(s), but your use-case works as expected:

# sfdisk -ql /dev/sdc
Device     Boot Start     End Sectors  Size Id Type
/dev/sdc1        2048   22527   20480   10M 83 Linux
/dev/sdc2       22528 1023999 1001472  489M 83 Linux

# sfdisk /dev/sdc --part-type 2 5 
The partition table has been altered.
Calling ioctl() to re-read partition table.
Syncing disks.

# sfdisk -ql /dev/sdc
Device     Boot Start     End Sectors  Size Id Type
/dev/sdc1        2048   22527   20480   10M 83 Linux
/dev/sdc2       22528 1023999 1001472  489M  5 Extended


The bugfix will be definitely in v2.27 (f23), is it necessary to backport it also to f22?

It would be nice to have it in F22, but don't sweat it if it's a
difficult backport.

Thanks guys!

util-linux-2.26.2-3.fc22 has been submitted as an update for Fedora 22.
https://admin.fedoraproject.org/updates/util-linux-2.26.2-3.fc22

Package util-linux-2.26.2-3.fc22:
* should fix your issue,
* was pushed to the Fedora 22 testing repository,
* should be available at your local mirror within two days.
Update it with:
# su -c 'yum update --enablerepo=updates-testing util-linux-2.26.2-3.fc22'
as soon as you are able to.
Please go to the following url:
https://admin.fedoraproject.org/updates/FEDORA-2015-13513/util-linux-2.26.2-3.fc22
then log in and leave karma (feedback).

util-linux-2.26.2-3.fc22 has been pushed to the Fedora 22 stable repository.  If problems still persist, please make note of it in this bug report.

*** Bug 1265078 has been marked as a duplicate of this bug. ***