I'm trying to populate a disk image in a container environment (podman) on Centos 8. I had originally run into issues with accessing the loop device from the container until finding on SO and other sources that I needed to run podman as root and with the `--privileged` option.

While this did solve my problem in general, I noticed that after rebooting my host, my first attempt to setup a loop device in the container would fail (`failed to set up loop device: No such file or directory`), but after exiting and relaunching the container it would succeed (/dev/loop0). If for some reason I needed to set up a second loop device (/dev/loop1) in the container (after having gotten a first one working), it too would fail until I exited and relaunched the container.

Experimenting a bit further, I found I could avoid the errors entirely if I ran `losetup --find --show <file created with dd>` enough times to attach the maximum number of loop devices I would need, then detached all of those with `losetup -D`, I could avoid the loop device errors in the container entirely.

I suspect I'm missing something obvious about what losetup does on the host which it is apparently not able to do entirely within a container, or maybe this is more specifically a Centos+podman+losetup issue. Any insight as to what is going on and why I have to preattach/detach the loop devices after a reboot to avoid problems inside my container?

Steps to reproduce on a Centos 8 system (after having attached/detached once following a reboot):

```
$ dd if=/dev/zero of=file bs=1024k count=10
10+0 records in
10+0 records out
10485760 bytes (10 MB, 10 MiB) copied, 0.00826706 s, 1.3 GB/s
$ cp file 1.img
$ cp file 2.img
$ cp file 3.img
$ cp file 4.img
$ sudo podman run -it --privileged --rm -v .:/images centos:8 bash

[root@2da5317bde3e /]# cd images
[root@2da5317bde3e images]# ls
1.img  2.img  3.img  4.img  file
[root@2da5317bde3e images]# losetup --find --show 1.img
/dev/loop0
[root@2da5317bde3e images]# losetup --find --show 2.img
losetup: 2.img: failed to set up loop device: No such file or directory
[root@2da5317bde3e images]# losetup -D
[root@2da5317bde3e images]# exit

exit
$ sudo podman run -it --privileged --rm -v .:/images centos:8 bash

[root@f9e41a21aea4 /]# cd images
[root@f9e41a21aea4 images]# losetup --find --show 1.img
/dev/loop0
[root@f9e41a21aea4 images]# losetup --find --show 2.img
/dev/loop1
[root@f9e41a21aea4 images]# losetup --find --show 3.img
losetup: 3.img: failed to set up loop device: No such file or directory
[root@f9e41a21aea4 /]# losetup -D
[root@f9e41a21aea4 images]# exit

exit
$ sudo podman run -it --privileged --rm -v .:/images centos:8 bash

[root@c93cb71b838a /]# cd images
[root@c93cb71b838a images]# losetup --find --show 1.img
/dev/loop0
[root@c93cb71b838a images]# losetup --find --show 2.img
/dev/loop1
[root@c93cb71b838a images]# losetup --find --show 3.img
/dev/loop2
[root@c93cb71b838a images]# losetup --find --show 4.img
losetup: 4.img: failed to set up loop device: No such file or directory

```