In distributed storage environments, storage resources are typically shared across multiple users, projects, and applications. Without effective constraint mechanisms, abnormal writes or erroneous operations from a single tenant can quickly consume large amounts of space or inodes, impacting system stability and cost control. Quota management provides a way to establish predictable resource boundaries in shared environments. In distributed systems, quota management is far more than just "setting a limit." The system must balance concurrent writes from multiple clients, asynchronous metadata updates, and overall throughput. At the same time, quota rules must be enforced at different levels of control. To address this, JuiceFS provides multi-level quota capabilities covering the entire file system, directories, and users, supporting scenarios ranging from overall capacity control to individual and team-level constraints.…