getdirtybuf
ibp = getdirtybuf(ibp, LOCK_PTR(ump), MNT_WAIT);
bp = getdirtybuf(bmsafemap->sm_buf, LOCK_PTR(ump), waitfor);
nbp = getdirtybuf(nbp, LOCK_PTR(ump), waitfor);
nbp = getdirtybuf(nbp, LOCK_PTR(ump), waitfor);
bp = getdirtybuf(bp, LOCK_PTR(ump), waitfor);
bp = getdirtybuf(bp, LOCK_PTR(ump), MNT_WAIT);
bp = getdirtybuf(bp, LOCK_PTR(ump), MNT_WAIT);
static struct buf *getdirtybuf(struct buf *, struct rwlock *, int);
if ((bp = getdirtybuf(bp, BO_LOCKPTR(bo), MNT_WAIT)) == NULL)