FreeBSD/sys/kern/vfs_bio.c
/*
 *	babarrierwrite:
 *
 *	Asynchronous barrier write.  Start output on a buffer, but do not
 *	wait for it to complete.  Place a write barrier after this write so
 *	that this buffer and all buffers written before it are committed to
 *	the disk before any buffers written after this write are committed
 *	to the disk.  The buffer is released when the output completes.
 */
Asynchronous barrier write.  Start output on a buffer, but do not
wait for it to complete.  Place a write barrier after this write so
that this buffer and all buffers written before it are committed to
the disk before any buffers written after this write are committed
to the disk.  The buffer is released when the output completes.
Asynchronous barrier write . Start output on a buffer but do not wait for it to complete . Place a write barrier after this write so that this buffer and all buffers written before it are committed to the disk before any buffers written after this write are committed to the disk . The buffer is released when the output completes .
void
babarrierwrite(struct buf *bp)
{
	bp->b_flags |= B_ASYNC | B_BARRIER;
	(void) bwrite(bp);
}
void babarrierwrite ( struct buf * bp ) { bp -> b_flags |= B_ASYNC | B_BARRIER ; ( void ) bwrite ( bp ) ; }
babarrierwrite:
      Asynchronous barrier write.
babarrierwrite : Asynchronous barrier write .