Directory fsync
Synchronization of a directory descriptor so that namespace changes such as file creation, removal, or rename can survive a crash according to the filesystem's durability semantics.
Calling fsync() on a file does not necessarily make the directory entry that names it durable. Creating a new file or publishing one with rename() also modifies metadata in the parent directory.
Crash-consistent publication sequences therefore often synchronize the directory after the file itself. Exact requirements depend on operating-system and filesystem semantics; in atomic publication, visibility and durability have to be verified as separate properties.