[Bug]: Quota rounding issues for new users created via OCS v1 API

⚠️ This issue respects the following points: ⚠️

• This is a bug, not a question or a configuration/webserver/proxy issue.
• This issue is not already reported on Github OR Nextcloud Community Forum (I've searched it).
• Nextcloud Server is up to date. See Maintenance and Release Schedule for supported versions.
• I agree to follow Nextcloud's Code of Conduct.

Bug description

I am not able to set a byte-accurate quota for a new Nextcloud user using the API endpoint /ocs/v1.php/cloud/users.

I use the following quota for the user: 28664560
But the user account is created with: 28626125

Adding 256 bytes to the quota leads to the same quota value for the user account. Thats why I'm pretty sure there must be any rounding issue.

Steps to reproduce

1. curl -u "ADMINUSER:ADMINPASSWORD" -H "OCS-APIRequest: true" -d "userid=TESTUSER" -d "password=TESTUSERPASSWORD" -d "quota=28664560" -X POST "https://NEXTCLOUD-URL/ocs/v1.php/cloud/users"

2. curl -u "ADMINUSER:ADMINPASSWORD" -H "OCS-APIRequest: true" "https://NEXTCLOUD-URL/ocs/v1.php/cloud/users/testuser"

Expected behavior

Output of curl #2 shows:

  <quota>
   <quota>28664560</quota>
   [...]
  </quota>

Nextcloud Server version

30

Operating system

Debian/Ubuntu

PHP engine version

PHP 8.2

Web server

Apache (supported)

Database engine version

MySQL

Is this bug present after an update or on a fresh install?

None

Are you using the Nextcloud Server Encryption module?

Encryption is Disabled

What user-backends are you using?

• Default user-backend (database)
• LDAP/ Active Directory
• SSO - SAML
• Other

Configuration report

# sudo -u www-data php occ config:list system
{
    "system": {
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            [HIDDEN]
        ],
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "mysql",
        "version": "30.0.10.1",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "mysql.utf8mb4": true,
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "installed": true,
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "overwriteprotocol": "https",
        "overwritewebroot": "\/",
        "mail_smtpmode": "smtp",
        "mail_smtpsecure": "ssl",
        "mail_sendmailmode": "smtp",
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauthtype": "LOGIN",
        "mail_smtpauth": 1,
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "465",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "maintenance_window_start": 1,
        "twofactor_enforced": "false",
        "twofactor_enforced_groups": [],
        "twofactor_enforced_excluded_groups": [],
        "maintenance": false,
        "theme": "",
        "loglevel": 2,
        "enable_previews": false,
        "skeletondirectory": "",
        "cors.allowed-origins": [
            [HIDDEN]
        ]
    }
}

List of activated Apps

# sudo -u www-data php occ app:list
Enabled:
  - activity: 3.0.0
  - app_api: 4.0.6
  - bruteforcesettings: 3.0.0
  - calendar: 5.2.4
  - circles: 30.0.0
  - cloud_federation_api: 1.13.0
  - contactsinteraction: 1.11.0
  - dashboard: 7.10.0
  - dav: 1.31.1
  - drawio: 3.0.9
  - federatedfilesharing: 1.20.0
  - federation: 1.20.0
  - files: 2.2.0
  - files_downloadlimit: 3.0.0
  - files_pdfviewer: 3.0.0
  - files_reminders: 1.3.0
  - files_sharing: 1.22.0
  - files_trashbin: 1.20.1
  - files_versions: 1.23.0
  - gpoddersync: 3.12.0
  - logreader: 3.0.0
  - lookup_server_connector: 1.18.0
  - metadata: 0.22.0
  - music: 2.1.4
  - nextcloud_announcements: 2.0.0
  - notifications: 3.0.0
  - oauth2: 1.18.1
  - password_policy: 2.0.0
  - photos: 3.0.2
  - privacy: 2.0.0
  - provisioning_api: 1.20.0
  - recommendations: 3.0.0
  - related_resources: 1.5.0
  - repod: 3.5.8
  - serverinfo: 2.0.0
  - settings: 1.13.0
  - sharebymail: 1.20.0
  - support: 2.0.0
  - survey_client: 2.0.0
  - systemtags: 1.20.0
  - text: 4.1.0
  - theming: 2.6.0
  - twofactor_backupcodes: 1.19.0
  - unroundedcorners: 1.1.4
  - updatenotification: 1.20.0
  - user_status: 1.10.0
  - viewer: 3.0.0
  - weather_status: 1.10.0
  - webapppassword: 25.3.0
  - webhook_listeners: 1.1.0-dev
  - workflowengine: 2.12.0
Disabled:
  - admin_audit: 1.20.0
  - comments: 1.20.1 (installed 1.15.0)
  - encryption: 2.18.0
  - files_external: 1.22.0
  - firstrunwizard: 3.0.0 (installed 3.0.0)
  - suspicious_login: 8.0.0
  - twofactor_nextcloud_notification: 4.0.0
  - twofactor_totp: 12.0.0-dev
  - user_ldap: 1.21.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

Additional info

No response

Start by reproducing the quota discrepancy with the documented POST and GET requests against /ocs/v1.php/cloud/users, using the exact value 28664560. Trace the OCS user-creation and user-query entry points to find where the quota changes; done means the GET response returns the exact requested byte value for a newly created user.