Allow quota write streams with unknown free space

[veryCrunchy]

• Resolves[Bug]: Chunked upload to object-store (S3) primary fails with 413 "Insufficient space" for any user with a finite quota, regardless of free space #61488
• Resolves[Bug]: WebDAV chunked uploads fail with S3 primary storage and per-user quota #61704

Summary

This PR allows quota-wrapped writeStream() calls to proceed when the reported free space is unknown.

With S3 primary object storage and a finite user quota, chunked WebDAV uploads can fail while writing chunks to the DAV upload staging path under uploads/.... For upload staging paths, Quota::free_space() delegates to the wrapped storage. Object-store-backed storage can report free space as unknown, but Quota::writeStream() currently compares the known stream size directly against that value and can raise NotEnoughSpaceException even though the user's destination quota has enough available space.

This changes Quota::writeStream() to treat unknown free space consistently with other quota wrapper write paths such as file_put_contents(), copy(), copyFromStorage(), and moveFromStorage().

A regression test covers writing a known-size stream to an uploads/... path when the wrapped storage reports unknown free space.

AI assistance was used to help inspect logs, reason through the relevant code path, draft the regression test, and organize validation. I prepared this patch after reproducing the issue on an affected Nextcloud instance. After the fix was drafted and tested locally, I found the existing report in #61488 and linked this PR to that issue.

Validation performed:

./autotest.sh sqlite lib/Files/Storage/Wrapper/QuotaTest.php

Result:

OK, but some tests were skipped!
Tests: 115, Assertions: 506, Skipped: 1.

Manual validation was also performed against an affected Nextcloud instance with S3 primary storage and a finite user quota:

• Chunked WebDAV upload failed before this patch with 413 Request Entity Too Large / Insufficient space.
• Applying this one-line change allowed the same chunked WebDAV upload to complete successfully.
• Previously queued rclone VFS cache uploads were able to proceed without new 413 Insufficient space errors after applying the fix.
• Backport requested for stable34. I checked stable33, stable32, stable31, and stable30; those branches do not contain the Quota::writeStream() override with the vulnerable $size < $free comparison.

TODO

• Maintainer review

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes are not required
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[Copilot]

Pull request overview

This PR fixes false NotEnoughSpaceException failures during quota-wrapped writeStream() writes when the underlying storage reports “unknown/unlimited” free space (negative sentinel), which particularly affects chunked WebDAV uploads to uploads/... on S3 primary storage.

Changes:

• Update OC\Files\Storage\Wrapper\Quota::writeStream() to allow known-size writes when free_space() is negative (unknown/unlimited), aligning with other quota wrapper write paths.
• Add a PHPUnit regression test covering a known-size stream write to an uploads/... path when the wrapped storage reports unknown free space.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
lib/private/Files/Storage/Wrapper/Quota.php	Treat negative free_space() as allowed in writeStream() to avoid false “insufficient space” on storages that can’t report free space.
tests/lib/Files/Storage/Wrapper/QuotaTest.php	Adds regression coverage for writing a sized stream to uploads/... when wrapped storage reports unknown free space.

---

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[veryCrunchy]

/backport to stable34

[Copilot]

Pull request overview

Copilot reviewed 2 out of 2 changed files in this pull request and generated no new comments.

[susnux]

Thank you for your contribution!
Two points regarding the format:

• Please use conventional commits: https://www.conventionalcommits.org/en/v1.0.0/
• Please add the disclosure of your AI usage to your commit as per AI policy: https://github.com/nextcloud/.github/blob/master/AI_POLICY.md#disclosure

[Mebus]

I was unfortunately able to reproduce the problem with NC 34.0.1, but was gladly able to fix the issue by applying the proposed patch. Please release this fix as soon as possible :-)

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[as598466]

Confirming this on a new production instance — same symptoms, same workaround.

Environment

• Nextcloud Server: <34.0.2>
• Primary storage: S3 object store (OVH Object Storage, S3-compatible)
• No totalSizeLimit configured in the objectstore arguments
• PHP <8.5>, <nginx>, <MariaDB 11.8>

Symptoms

• User quota set to 5 GB, well under usage. Small files upload fine.
• Any upload large enough to be chunked (~100 MB and above, and consistently for 1 GB+ files) fails with Insufficient space.
• Setting the same user's quota to Unlimited makes the exact same upload succeed immediately, with no other change.
• occ files:scan reports no discrepancy, and occ user:info shows the expected free quota.

Confirmed fix

Changing the single comparison in lib/private/Files/Storage/Wrapper/Quota.php:

 public function writeStream(string $path, $stream, ?int $size = null): int {
// ...
if ($size !== null) {
- if ($size < $free) {+ if ($free < 0 || $size < $free) {
return parent::writeStream($path, $stream, $size);
} else {
throw new NotEnoughSpaceException();
}
}

The root cause analysis in the issue description matches what I see: the chunk parts land under uploads/, which Quota::free_space() delegates to the wrapped storage, and ObjectStoreStorage::free_space() returns FileInfo::SPACE_UNLIMITED (-3) when no total size limit is set. Quota::writeStream() then evaluates $size < -3, which is always false, and throws NotEnoughSpaceException → EntityTooLarge / 413.

One thing worth adding for other people hitting this: the regression is not limited to 34.x. I checked the released tags and the Quota::writeStream() override introduced by #59995 is also present in 32.0.13:

So a backport to stable32 looks necessary in addition to stable34.