Description of problem:
Bug resulted in the Blivet-GUI, under an extended partition, by creating and selecting a logical partition’s filesystem as unformatted.

Version-Release number of selected component:
anaconda-26.21.7-1

The following was filed automatically by anaconda:
anaconda 26.21.7-1 exception report
Traceback (most recent call first):
  File "/usr/lib/python3.6/site-packages/blivetgui/blivetgui.py", line 219, in _reraise_exception
    raise type(exception)(str(exception) + "\n" + traceback)
  File "/usr/lib/python3.6/site-packages/blivetgui/blivetgui.py", line 448, in add_device
    self._reraise_exception(result.exception, result.traceback)
_ped.PartitionException: Can't add a logical partition to /dev/vda, because there is no extended partition.
Traceback (most recent call last):
  File "/usr/lib/python3.6/site-packages/blivetgui/blivet_utils.py", line 1146, in add_device
    blivet.partitioning.do_partitioning(self.storage)
  File "/usr/lib/python3.6/site-packages/blivet/partitioning.py", line 582, in do_partitioning
    allocate_partitions(storage, disks, partitions, free)
  File "/usr/lib/python3.6/site-packages/blivet/partitioning.py", line 961, in allocate_partitions
    _part.req_start_sector, _part.req_end_sector)
  File "/usr/lib/python3.6/site-packages/blivet/partitioning.py", line 446, in add_partition
    constraint=constraint)
  File "/usr/lib64/python3.6/site-packages/parted/decorators.py", line 42, in new
    ret = fn(*args, **kwds)
  File "/usr/lib64/python3.6/site-packages/parted/disk.py", line 245, in addPartition
    constraint.getPedConstraint())
_ped.PartitionException: Can't add a logical partition to /dev/vda, because there is no extended partition.


Additional info:
addons:         com_redhat_docker, com_redhat_kdump
cmdline:        /usr/libexec/system-python  /sbin/anaconda
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         4.11.0-2.fc26.x86_64
product:        Fedora
release:        Cannot get release name.
type:           anaconda
version:        26

Potential duplicate: bug 1442020