Description of problem:
Created mount point /data for silverblue, ran installation, kaboom.

While verifying that bug 1845095 is fixed, this came up later. The first mount seemed to be ok.

Silverblue compose https://kojipkgs.fedoraproject.org/compose/rawhide/Fedora-Rawhide-20210628.n.0/compose/Silverblue/x86_64/iso/Fedora-Silverblue-ostree-x86_64-Rawhide-20210628.n.0.iso

Version-Release number of selected component:
anaconda-35.17

The following was filed automatically by anaconda:
anaconda 35.17 exception report
Traceback (most recent call first):
  File "/usr/lib/python3.10/site-packages/dasbus/client/handler.py", line 497, in _handle_method_error
    raise exception from None
  File "/usr/lib/python3.10/site-packages/dasbus/client/handler.py", line 477, in _get_method_reply
    return self._handle_method_error(error)
  File "/usr/lib/python3.10/site-packages/dasbus/client/handler.py", line 444, in _call_method
    return self._get_method_reply(
  File "/usr/lib64/python3.10/site-packages/pyanaconda/modules/common/task/__init__.py", line 46, in sync_run_task
    task_proxy.Finish()
  File "/usr/lib64/python3.10/site-packages/pyanaconda/payload/rpmostreepayload.py", line 120, in _run_tasks
    sync_run_task(task_proxy)
  File "/usr/lib64/python3.10/site-packages/pyanaconda/payload/rpmostreepayload.py", line 96, in install
    self._run_tasks(task_paths, self._progress_cb)
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation_tasks.py", line 458, in run_task
    self._task(*self._task_args, **self._task_kwargs)
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation_tasks.py", line 496, in start
    self.run_task()
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation_tasks.py", line 311, in start
    item.start()
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation_tasks.py", line 311, in start
    item.start()
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation_tasks.py", line 311, in start
    item.start()
  File "/usr/lib64/python3.10/site-packages/pyanaconda/installation.py", line 405, in run_installation
    queue.start()
  File "/usr/lib64/python3.10/threading.py", line 946, in run
    self._target(*self._args, **self._kwargs)
  File "/usr/lib64/python3.10/site-packages/pyanaconda/threading.py", line 275, in run
    threading.Thread.run(self)
dasbus.error.DBusError: [Errno 1] Operace není povolena: '/mnt/sysroot/data'

Additional info:
addons:         com_redhat_kdump
cmdline:        /usr/bin/python3  /sbin/anaconda
cmdline_file:   BOOT_IMAGE=vmlinuz initrd=initrd.img inst.stage2=hd:LABEL=Fedora-SB-ostree-x86_64-rawh quiet
dnf.librepo.log: 
executable:     /sbin/anaconda
hashmarkername: anaconda
kernel:         5.13.0-0.rc7.20210625git44db63d1ad8d.55.fc35.x86_64
product:        Fedora
release:        Fedora release 35 (Rawhide)
release_type:   pre-release
type:           anaconda
version:        rawhide