edge-simplified-installer image hangs when filesystem customization mountpoint size is bigger than 8 GiB

[mcattamoredhat]

Describe the bug
Since filesystem customization is available in simplified-installer image type in RHEL-9.5 fix-fs-customization:exec start and stop logic, it has been seen that when the installer blueprint is configured with a mount point whose partition size is equal or bigger than 8 GiB, the image is not able to boot properly and installation hangs.
More details and logs have been gathered in the following Jira card Custom partition mount points in raw/ami/vsphere and simplified installer test cases

Environment

• OS version (/etc/os-release and /etc/redhat-release):

$ cat /etc/os-release 
NAME="Red Hat Enterprise Linux"
VERSION="9.5 (Plow)"
ID="rhel"
ID_LIKE="fedora"
VERSION_ID="9.5"
PLATFORM_ID="platform:el9"
PRETTY_NAME="Red Hat Enterprise Linux 9.5 Beta (Plow)"
ANSI_COLOR="0;31"
LOGO="fedora-logo-icon"
CPE_NAME="cpe:/o:redhat:enterprise_linux:9::baseos"
HOME_URL="https://www.redhat.com/"
DOCUMENTATION_URL="https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/9"
BUG_REPORT_URL="https://issues.redhat.com/"

REDHAT_BUGZILLA_PRODUCT="Red Hat Enterprise Linux 9"
REDHAT_BUGZILLA_PRODUCT_VERSION=9.5
REDHAT_SUPPORT_PRODUCT="Red Hat Enterprise Linux"
REDHAT_SUPPORT_PRODUCT_VERSION="9.5 Beta"

• osbuild-composer version (rpm -qi osbuild-composer)

[admin@simp-inst-rhel-9-5-240904 ~]$ rpm -qi osbuild-composer
Name        : osbuild-composer
Version     : 120
Release     : 1.20240904git2447408.el9
Architecture: x86_64
Install Date: Wed Sep  4 10:54:23 2024
Group       : Unspecified
Size        : 19022
License     : Apache-2.0
Signature   : (none)
Source RPM  : osbuild-composer-120-1.20240904git2447408.el9.src.rpm
Build Date  : Wed Sep  4 10:45:50 2024
Build Host  : simp-inst-rhel-9-5-240904
URL         : https://github.com/osbuild/osbuild-composer
Summary     : An image building service based on osbuild
Description :

A service for building customized OS artifacts, such as VM images and OSTree
commits, that uses osbuild under the hood. Besides building images for local
usage, it can also upload images directly to cloud.

It is compatible with composer-cli and cockpit-composer clients.

To Reproduce
Steps to reproduce the behavior:

git clone -b fs-custom-lvs-raw-image https://github.com/mcattamoredhat/osbuild-composer.git && cd osbuild-composer
make rpm && sudo dnf -y install rpmbuild/RPMS/x86_64/*
cd test/cases
EDGE_USER_PASSWORD=<edge_user_password> ./ostree-simplified-installer.sh

Blueprint filesystem customization:

[[customizations.filesystem]]
mountpoint = "/foo/bar"
size=2147483648
[[customizations.filesystem]]
mountpoint = "/foo"
size=8589934592
[[customizations.filesystem]]
mountpoint = "/var/myfiles"
size= "1 GiB"

Expected behavior
The edge VMs are created and the filesystem customization remains in the system even after system upgrade. This is the behavior that is currently seen in edge-raw-image, ami/vsphere image test cases.

Additional context
Add any other context about the problem here.