File Locking

A mechanism to prevent concurrent modifications to the same file by multiple clients or processes simultaneously. Advisory locks (such as POSIX flock) require cooperating processes to honor them voluntarily, while mandatory locks are enforced by the kernel. WebDAV defines HTTP LOCK and UNLOCK methods for distributed file locking, and NFS provides its own locking protocol. Proper file locking is essential in multi-user FTP servers and collaborative editing environments.