mount of compressed erofs shows corrupted data

[Jungkook Park]

In some cases, file contents are corrupted if I mount a lz4 compressed erofs image file.

How to reproduce:

1. Download the attached file (pip-22.0.2-py3-none-any.whl). Actually, this file is installed from python3.10-venv package and is originally located at /usr/share/python-wheels/pip-22.0.2-py3-none-any.whl.
2. `mkdir source && mv pip-22.0.2-py3-none-any.whl source/`
3. `mkfs.erofs uncomp.erofs source/`
4. `mkfs.erofs -z lz4 comp.erofs source/`
5. `mkdir mount_uncomp && mount uncomp.erofs mount_uncomp/`
6. `mkdir mount_comp && mount comp.erofs mount_comp/`
7. compare the hashes of the file for each mountpoint.

If I run the above code, I found the result
- md5sum source/pip-22.0.2-py3-none-any.whl : 5a1376d56e14bd0127f47e0d6a042479
- md5sum mount_uncomp/pip-22.0.2-py3-none-any.whl : 5a1376d56e14bd0127f47e0d6a042479
- md5sum mount_comp/pip-22.0.2-py3-none-any.whl : 8e01bd5ea2108f41684ba724f6d15101

And the diff of their hexdump shows 4 bytes mismatch.

ProblemType: Bug
DistroRelease: Ubuntu 22.04
Package: linux-image-6.2.0-35-generic 6.2.0-35.35~22.04.1
ProcVersionSignature: Ubuntu 6.2.0-35.35~22.04.1-generic 6.2.16
Uname: Linux 6.2.0-35-generic x86_64
ApportVersion: 2.20.11-0ubuntu82.5
Architecture: amd64
CasperMD5CheckResult: pass
CloudArchitecture: x86_64
CloudID: none
CloudName: none
CloudPlatform: none
CloudSubPlatform: config
Date: Mon Oct 30 14:04:37 2023
InstallationDate: Installed on 2022-11-08 (356 days ago)
InstallationMedia: Ubuntu-Server 22.04.1 LTS "Jammy Jellyfish" - Release amd64 (20220809)
ProcEnviron:
 TERM=screen
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: linux-signed-hwe-6.2
UpgradeStatus: No upgrade log present (probably fresh install)