convfsync

convfsync is a system call in some Unix-like operating systems that allows a process to synchronize a file with its on-disk representation. It is similar to the fsync system call but offers additional control over which parts of the file are synchronized. Specifically, convfsync can be used to synchronize data from a specified offset up to a specified length within a file. This granular control can be beneficial for performance in certain applications that frequently update only small portions of large files.

When convfsync is invoked, the system ensures that all modified data and metadata within the specified range are written from the operating system's buffer cache to the underlying storage device. This operation is crucial for data integrity, as it guarantees that changes are made persistent even in the event of a system crash or power failure. Unlike fsync, which synchronizes the entire file, convfsync's targeted approach can reduce the amount of disk I/O required, potentially leading to improved performance for applications that can leverage its selective synchronization capabilities. The exact implementation and availability of convfsync may vary across different operating systems and file systems.