write_behind
write_behind(file, pf->f_convert);
write_behind(file, pf->f_convert);
static int write_behind = 1;
SYSCTL_INT(_vfs, OID_AUTO, write_behind, CTLFLAG_RW, &write_behind, 0,
switch(write_behind) {
write_behind(file, convert);
write_behind(file, convert); /* flush last buffer */
(void)write_behind(file, convert); /* flush it */
int write_behind(FILE *, int);