ovl-idmapped-mount.sh in ubuntu_overlayfs_smoke_test failed with `mount: /root/ovl: wrong fs type, bad option, bad superblock on overlay, missing codepage or h elper program, or other error.`

[Francis Ginther]

The ovl-idmapped-mount.sh test fails on some kernels. So far, this is seen on jammy/linux.

21:55:19 INFO | START ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh timestamp=1691790919 timeout=300 localtime=Aug 11 21:55:19
21:55:19 DEBUG| Persistent state client._record_indent now set to 2
21:55:19 DEBUG| Persistent state client.unexpected_reboot now set to ('ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh', 'ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh')
21:55:19 DEBUG| Waiting for pid 3335 for 300 seconds
21:55:19 WARNI| System python is too old, crash handling disabled
21:55:19 DEBUG| Running 'sudo -iu ubuntu /home/ubuntu/autotest/client/tmp/ubuntu_overlayfs_smoke_test/src/overlay-shiftfs-tests/tests/ovl-idmapped-mount.sh'
21:55:27 DEBUG| [stdout] Creating idmap-test
21:55:43 DEBUG| [stdout]
[snip]
Starting idmap-test
21:55:44 ERROR| [stderr] + mkdir work upper lower ovl
21:55:44 ERROR| [stderr] + mount -t overlay overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl
21:55:44 ERROR| [stderr] mount: /root/ovl: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error.
21:55:44 DEBUG| [stdout]
[snip]
21:55:57 DEBUG| FAIL
21:55:57 DEBUG| stderr:
21:55:57 DEBUG| + mkdir work upper lower ovl
21:55:57 DEBUG| + mount -t overlay overlay -o lowerdir=lower,upperdir=upper,workdir=work ovl
21:55:57 DEBUG| mount: /root/ovl: wrong fs type, bad option, bad superblock on overlay, missing codepage or helper program, or other error.
21:55:57 INFO | ERROR ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh ubuntu_overlayfs_smoke_test.ovl-idmapped-mount.sh timestamp=1691790957 localtime=Aug 11 21:55:57 Command <sudo -iu ubuntu /home/ubuntu/autotest/client/tmp/ubuntu_overlayfs_smoke_test/src/overlay-shiftfs-tests/tests/ovl-idmapped-mount.sh> failed, rc=1, Command returned non-zero

[Jian Hui Lee (jianhuilee)]

issue is seen on mtk jammy 5.15 kernel.
'overlay: support idmapped layers' was supported since v5.18: https://<email address hidden>/
the failure is expected.