> Would it be ok to use
>     ubc_alloc(&vp->v_uobj, ..)
>     uiomove()
>     ubc_release(.., UBC_UNMAP)

it doesn't allocate blocks.

> or
>     vn_rdwr()
>     VOP_PUTPAGES(.., PGO_CLEANIT|PGO_SYNCIO|PGO_FREE);

i think it works.  (for ubcified filesystems.)

if you feel it's too much work for the intermediate solution,
please say so.  i will just revive ffs VOP_BALLOC in that case.

YAMAMOTO Takashi