The No-Order File System Modern file systems use ordering points to maintain consistency in the face of system crashes. However, such ordering leads to lower performance, higher complexity, and a strong and perhaps naive dependence on lower layers to correctly enforce the ordering of writes. Lower layers such as the hypervisor in virtual machine systems, and the disk in baremetal systems often fail to propagate or act on flushes correctly, thereby failing to enforce ordering. F_FULLFSYNC: Does the same thing as fsync(2) then asks the drive to flush all buffered data to the permanent storage device (arg is ignored). This is currently implemented on HFS, MS-DOS (FAT), and Universal Disk Format (UDF) file systems. The operation may take quite a while to complete.