B_DONTNEED
(flags & B_DONTNEED) == 0)
(flags & ~(B_ASYNC|B_DONTNEED|B_FREE)) == 0) {
(B_DONTNEED | B_FREE | B_FORCE | B_ASYNC),
(flags & ~(B_ASYNC|B_DONTNEED|B_FREE)) == 0) {
bflags |= B_DONTNEED;
(B_DONTNEED|B_FREE|B_ASYNC),
(flags & B_DONTNEED), kcred);
VN_DISPOSE(pp, B_FREE, (flags & B_DONTNEED), kcred);
bflags |= B_DONTNEED;