Storage limit per location

S3 has no bucket quota, so NG Backup enforces one: before a pack is
uploaded, the stored size plus the pack must stay under the location's
limit, otherwise the backup stops with an error (and administrators are
notified through the failed run). Repacking during prune is exempt, as it
is how space is freed. occ backup:target:limit NAME [SIZE|none].

Also ignore credential files in the repository.

lib/Service/TargetService.php

@@ -90,6 +90,12 @@ class TargetService {
 		return ctype_digit($nameOrId) ? $this->mapper->find((int)$nameOrId) : $this->mapper->findByName($nameOrId);
 	}
 
+	/** Size limit for the data stored on this location (null = none). */
+	public function setMaxBytes(Target $target, ?int $maxBytes): Target {
+		$target->setMaxBytes($maxBytes);
+		return $this->mapper->update($target);
+	}
+
 	public function setAppendOnly(Target $target, bool $appendOnly): Target {
 		$target->setAppendOnly($appendOnly);
 		return $this->mapper->update($target);
@@ -109,6 +115,7 @@ class TargetService {
 		if ($target->getRepositoryId() !== null && $repo->id() !== $target->getRepositoryId()) {
 			throw new \RuntimeException('The target now contains a different repository than when it was added');
 		}
+		$repo->setMaxBytes($target->getMaxBytes());
 		return $repo;
 	}