Function vnode_pager_generic_getpages_done

freebsd/vm/vnode_pager.c:1117–1199

}

static int
vnode_pager_generic_getpages_done(struct buf *bp)
{
	vm_object_t object;
	off_t tfoff, nextoff;
	int i, error;

	KASSERT((bp->b_ioflags & BIO_ERROR) == 0 || bp->b_error != 0,
	    ("%s: buf error but b_error == 0\n", __func__));
	error = (bp->b_ioflags & BIO_ERROR) != 0 ? bp->b_error : 0;
	object = bp->b_vp->v_object;

	if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
		if (!buf_mapped(bp)) {
			bp->b_data = bp->b_kvabase;
			pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
			    bp->b_npages);
		}
		bzero(bp->b_data + bp->b_bcount,
		    PAGE_SIZE * bp->b_npages - bp->b_bcount);
	}
	if (buf_mapped(bp)) {
		pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
		bp->b_data = unmapped_buf;
	}

	/*
	 * If the read failed, we must free any read ahead/behind pages here.
	 * The requested pages are freed by the caller (for sync requests)
	 * or by the bp->b_pgiodone callback (for async requests).
	 */
	if (error != 0) {
		VM_OBJECT_WLOCK(object);
		for (i = 0; i < bp->b_pgbefore; i++)
			vm_page_free_invalid(bp->b_pages[i]);
		for (i = bp->b_npages - bp->b_pgafter; i < bp->b_npages; i++)
			vm_page_free_invalid(bp->b_pages[i]);
		VM_OBJECT_WUNLOCK(object);
		return (error);
	}

	/* Read lock to protect size. */
	VM_OBJECT_RLOCK(object);
	for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
	    i < bp->b_npages; i++, tfoff = nextoff) {
		vm_page_t mt;

		nextoff = tfoff + PAGE_SIZE;
		mt = bp->b_pages[i];
		if (mt == bogus_page)
			continue;

		if (nextoff <= object->un_pager.vnp.vnp_size) {
			/*
			 * Read filled up entire page.
			 */
			vm_page_valid(mt);
			KASSERT(mt->dirty == 0,