BFS does this as part of journal management, but not as part of block
cache synchronization (which makes sense, as flushing it then would
defeat the purpose of the drive's write cache.) No other file system
seems to touch it at all, so we should do it as part of an explicit sync.
This may help with some of the filesystem corruption issues, as it seems
that on slow disks, the drive might not have enough time to flush the cache
before it is powered off (or on some SATA/AHCI based disks, it is not flushed
before close at all), so triggering it here and, as the ioctl is supposed to be
synchronous, waiting for it also, seems to make sense.
Change-Id: I7d9992c21ca4b59c839711dcc96c973b4b8df052
Reviewed-on: https://review.haiku-os.org/530
Reviewed-by: Jérôme Duval <jerome.duval@gmail.com>
Reviewed-by: waddlesplash <waddlesplash@gmail.com>
74e882b39b