[Bug]: GenericFileException when uploading files to a shared folder

⚠️ 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

When uploading a bunch of pictures to a shared folder, there were a lot of "An unknown error has occurred" errors. In the logs, I see GenericFileExceptions (from App "Index") and corresponding PHP errors ("Failed to open stream: No such file or directory", see below).

Steps to reproduce

1. Create folder, share it
2. Upload files
3. "An unknown error has occurred"

Expected behavior

no error should occur

Nextcloud Server version

29

Operating system

Other

PHP engine version

PHP 8.2

Web server

Apache (supported)

Database engine version

PostgreSQL

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

{
    "system": {
        "htaccess.RewriteBase": "\/",
        "memcache.local": "\\OC\\Memcache\\APCu",
        "apps_paths": [
            {
                "path": "\/var\/www\/html\/apps",
                "url": "\/apps",
                "writable": false
            },
            {
                "path": "\/var\/www\/html\/custom_apps",
                "url": "\/custom_apps",
                "writable": true
            }
        ],
        "passwordsalt": "***REMOVED SENSITIVE VALUE***",
        "secret": "***REMOVED SENSITIVE VALUE***",
        "trusted_domains": [
            "localhost",
            "akki",
            "akki.fin.earth",
            "192.168.200.9",
            "creideiki.homelinux.net",
            "cloud.helmut-bender.de"
        ],
        "trusted_proxies": "***REMOVED SENSITIVE VALUE***",
        "datadirectory": "***REMOVED SENSITIVE VALUE***",
        "dbtype": "pgsql",
        "version": "29.0.10.1",
        "overwrite.cli.url": "https:\/\/cloud.helmut-bender.de",
        "overwritehost": "cloud.helmut-bender.de",
        "overwritewebroot": "\/",
        "overwriteprotocol": "https",
        "dbname": "***REMOVED SENSITIVE VALUE***",
        "dbhost": "***REMOVED SENSITIVE VALUE***",
        "dbport": "",
        "dbtableprefix": "oc_",
        "dbuser": "***REMOVED SENSITIVE VALUE***",
        "dbpassword": "***REMOVED SENSITIVE VALUE***",
        "default_phone_region": "DE",
        "installed": true,
        "instanceid": "***REMOVED SENSITIVE VALUE***",
        "maintenance": false,
        "mail_from_address": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpmode": "smtp",
        "mail_sendmailmode": "smtp",
        "mail_domain": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauth": 1,
        "mail_smtphost": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpport": "587",
        "mail_smtpname": "***REMOVED SENSITIVE VALUE***",
        "mail_smtppassword": "***REMOVED SENSITIVE VALUE***",
        "mail_smtpauthtype": "PLAIN",
        "loglevel": 0,
        "mail_smtpsecure": "tls",
        "memcache.distributed": "\\OC\\Memcache\\Redis",
        "memcache.locking": "\\OC\\Memcache\\Redis",
        "redis": {
            "host": "***REMOVED SENSITIVE VALUE***",
            "password": "***REMOVED SENSITIVE VALUE***",
            "port": 6379
        },
        "theme": "",
        "app_install_overwrite": [
            "maps"
        ],
        "maintenance_window_start": 23,
        "upgrade.disable-web": true
    }
}

List of activated Apps

Enabled:
  - activity: 2.21.1
  - bruteforcesettings: 2.9.0
  - calendar: 4.7.16
  - circles: 29.0.0-dev
  - cloud_federation_api: 1.12.0
  - comments: 1.19.0
  - contacts: 6.0.1
  - contactsinteraction: 1.10.0
  - dashboard: 7.9.0
  - dav: 1.30.1
  - deck: 1.13.3
  - epubviewer: 1.6.7
  - federatedfilesharing: 1.19.0
  - federation: 1.19.0
  - files: 2.1.1
  - files_downloadlimit: 2.0.0
  - files_external: 1.21.0
  - files_pdfviewer: 2.10.0
  - files_reminders: 1.2.0
  - files_sharing: 1.21.0
  - files_trashbin: 1.19.0
  - files_versions: 1.22.0
  - firstrunwizard: 2.18.0
  - forms: 4.3.4
  - groupfolders: 17.0.8
  - integration_openstreetmap: 1.0.12
  - logreader: 2.14.0
  - lookup_server_connector: 1.17.0
  - maps: 1.4.0
  - metadata: 0.21.0
  - nextcloud_announcements: 1.18.0
  - notes: 4.11.0
  - notifications: 2.17.0
  - oauth2: 1.17.1
  - password_policy: 1.19.0
  - photos: 2.5.0
  - privacy: 1.13.0
  - provisioning_api: 1.19.0
  - recommendations: 2.1.0
  - related_resources: 1.4.0
  - serverinfo: 1.19.0
  - settings: 1.12.0
  - sharebymail: 1.19.0
  - support: 1.12.0
  - survey_client: 1.17.0
  - systemtags: 1.19.0
  - tasks: 0.16.1
  - text: 3.10.1
  - theming: 2.4.0
  - twofactor_backupcodes: 1.18.0
  - updatenotification: 1.19.1
  - user_status: 1.9.0
  - viewer: 2.3.0
  - weather_status: 1.9.0
  - workflowengine: 2.11.0
Disabled:
  - admin_audit: 1.19.0
  - encryption: 2.17.0
  - spreed: 19.0.11 (installed 19.0.11)
  - suspicious_login: 7.0.0
  - twofactor_totp: 11.0.0-dev
  - user_ldap: 1.20.0

Nextcloud Signing status

No errors have been found.

Nextcloud Logs

{"reqId":"eKhJe8j51sFuomAOD60J","level":3,"time":"2024-12-25T10:26:35+00:00","remoteAddr":"91.89.167.224","user":"hab","app":"index","method":"GET","url":"/index.phpiew?fileId=46219&x=250&y=250","message":"Exception thrown: OCP\\Files\\GenericFileException","userAgent":"Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0","version":"29.0.10.1","exception":{"Exception":"OCP\\Files\\GenericFileException","Message":"","Code":0,"Trace":[{"file":"/var/www/html/lib/private/Files/SimpleFS/SimpleFile.php","line":74,"function":"getContent","class":"OC\\Files\\Node\\File","type":"->","args":[]},{"file":"/var/www/html/lib/public/AppFramework/Http/FileDisplayResponse.php","line":70,"function":"getContent","class":"OC\\Files\\SimpleFS\\SimpleFile","type":"->","args":[]},{"file":"/var/www/html/lib/private/AppFramework/App.php","line":241,"function":"callback","class":"OCP\\AppFramework\\Http\\FileDisplayResponse","type":"->","args":[{"__class__":"OC\\AppFramework\\Http\\Output"}]},{"file":"/var/www/html/lib/private/Route/Router.php","line":331,"function":"main","class":"OC\\AppFramework\\App","type":"::","args":["OC\\Core\\Controller\\PreviewController","getPreviewByFileId",{"__class__":"OC\\AppFramework\\DependencyInjection\\DIContainer"},{"_route":"core.preview.getpreviewbyfileid"}]},{"file":"/var/www/html/lib/base.php","line":1060,"function":"match","class":"OC\\Route\\Router","type":"->","args":["/core/preview"]},{"file":"/var/www/html/index.php","line":49,"function":"handleRequest","class":"OC","type":"::","args":[]}],"File":"/var/www/html/lib/private/Files/Node/File.php","Line":56,"message":"","exception":[],"CustomMessage":"Exception thrown: OCP\\Files\\GenericFileException"},"id":"676bddf69c419"}

{"reqId":"eKhJe8j51sFuomAOD60J","level":3,"time":"2024-12-25T10:26:35+00:00","remoteAddr":"91.89.167.224","user":"hab","app":"PHP","method":"GET","url":"/index.phpiew?fileId=46219&x=250&y=250","message":"file_get_contents(/var/www/html/data/appdata_ocwflvc6mxkf/preview/b/b/f/9/6/d/e/46219/256-256-crop.png): Failed to open stream: No such file or directory at /var/www/html/lib/private/Files/Storage/Local.php#331","userAgent":"Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:133.0) Gecko/20100101 Firefox/133.0","version":"29.0.10.1","data":{"app":"PHP"},"id":"676bddf69c427"}

Additional info

OS: Docker image (nextcloud:29-apache) on QNAP QTS (Linux 5.10.60-qnap x86_64)

Start by tracing the preview request through lib/private/Files/SimpleFS/SimpleFile.php, lib/public/AppFramework/Http/FileDisplayResponse.php, and lib/private/Files/Storage/Local.php, using the supplied stack trace and PreviewController route. Reproduce an upload to a shared folder and confirm that previews no longer produce GenericFileException or missing-file errors.