[Bug]: Cannot upload file that exactly fits the storage quota

[saw-jan]

⚠️ 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

1️⃣ ❌ Cannot upload content that exactly fits the quota

curl -XPUT 'http://nextcloud.local/remote.php/dav/files/demo/lorem.txt' -d "1234567890" -u demo:demo -v

< HTTP/2 413
...
<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns">
  <s:exception>OCA\DAV\Connector\Sabre\Exception\EntityTooLarge</s:exception>
  <s:message>Insufficient space</s:message>
</d:error>

2️⃣ ❌ Cannot download the existing file if the storage is completely full.

When trying to download the file after the storage quota get completely used. (e.g: 10B/10B), the download request fails with 503 status error.

curl 'http://nextcloud.local/remote.php/dav/files/demo/lorem.txt' -u demo:demo -v

< HTTP/2 503
...
<?xml version="1.0" encoding="utf-8"?>
<d:error xmlns:d="DAV:" xmlns:s="http://sabredav.org/ns">
  <s:exception>Sabre\DAV\Exception\ServiceUnavailable</s:exception>
  <s:message>Could not open file: lorem.txt (345), file does seem to exist</s:message>
</d:error>

👉 NOTE: the above actions work in NC33 (Nextcloud Hub 26 Winter (33.0.2))

Steps to reproduce

Upload:

1. Create a user with some bytes of quota (e.g: 10B)
2. As new user, Upload a file that fits the 10B ❌

Donwload:

1. As user, upload 8bytes file
2. As admin, reduce the user quota to 8B
3. As user, try to download that file ❌

Expected behavior

Should be able to download existing files.

Nextcloud Server version

34 (master): Nextcloud Hub 26 Spring (34.0.0 beta 4)

Operating system

None

PHP engine version

None

Web server

None

Database engine version

None

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

None

Are you using the Nextcloud Server Encryption module?

None

What user-backends are you using?

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

Configuration report

List of activated Apps

Nextcloud Signing status

Nextcloud Logs

Additional info

No response