Ejemplo n.º 1
0
static void
vnode_pager_generic_getpages_done_async(struct buf *bp)
{
	int error;

	error = vnode_pager_generic_getpages_done(bp);
	bp->b_pager.pg_iodone(bp->b_caller1, bp->b_pages,
	  bp->b_pager.pg_reqpage, error);
	for (int i = 0; i < bp->b_npages; i++)
		bp->b_pages[i] = NULL;
	bp->b_vp = NULL;
	pbrelbo(bp);
	relpbuf(bp, &vnode_async_pbuf_freecnt);
}
Ejemplo n.º 2
0
static void
vnode_pager_generic_getpages_done_async(struct buf *bp)
{
	int error;

	error = vnode_pager_generic_getpages_done(bp);
	/* Run the iodone upon the requested range. */
	bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
	    bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
	for (int i = 0; i < bp->b_npages; i++)
		bp->b_pages[i] = NULL;
	bp->b_vp = NULL;
	pbrelbo(bp);
	relpbuf(bp, &vnode_async_pbuf_freecnt);
}
Ejemplo n.º 3
0
/*
 * This is now called from local media FS's to operate against their
 * own vnodes if they fail to implement VOP_GETPAGES.
 */
int
vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
    int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
{
	vm_object_t object;
	struct bufobj *bo;
	struct buf *bp;
	off_t foff;
#ifdef INVARIANTS
	off_t blkno0;
#endif
	int bsize, pagesperblock, *freecnt;
	int error, before, after, rbehind, rahead, poff, i;
	int bytecount, secmask;

	KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
	    ("%s does not support devices", __func__));

	if (vp->v_iflag & VI_DOOMED)
		return (VM_PAGER_BAD);

	object = vp->v_object;
	foff = IDX_TO_OFF(m[0]->pindex);
	bsize = vp->v_mount->mnt_stat.f_iosize;
	pagesperblock = bsize / PAGE_SIZE;

	KASSERT(foff < object->un_pager.vnp.vnp_size,
	    ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
	KASSERT(count <= sizeof(bp->b_pages),
	    ("%s: requested %d pages", __func__, count));

	/*
	 * The last page has valid blocks.  Invalid part can only
	 * exist at the end of file, and the page is made fully valid
	 * by zeroing in vm_pager_get_pages().
	 */
	if (m[count - 1]->valid != 0 && --count == 0) {
		if (iodone != NULL)
			iodone(arg, m, 1, 0);
		return (VM_PAGER_OK);
	}

	/*
	 * Synchronous and asynchronous paging operations use different
	 * free pbuf counters.  This is done to avoid asynchronous requests
	 * to consume all pbufs.
	 * Allocate the pbuf at the very beginning of the function, so that
	 * if we are low on certain kind of pbufs don't even proceed to BMAP,
	 * but sleep.
	 */
	freecnt = iodone != NULL ?
	    &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
	bp = getpbuf(freecnt);

	/*
	 * Get the underlying device blocks for the file with VOP_BMAP().
	 * If the file system doesn't support VOP_BMAP, use old way of
	 * getting pages via VOP_READ.
	 */
	error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
	if (error == EOPNOTSUPP) {
		relpbuf(bp, freecnt);
		VM_OBJECT_WLOCK(object);
		for (i = 0; i < count; i++) {
			PCPU_INC(cnt.v_vnodein);
			PCPU_INC(cnt.v_vnodepgsin);
			error = vnode_pager_input_old(object, m[i]);
			if (error)
				break;
		}
		VM_OBJECT_WUNLOCK(object);
		return (error);
	} else if (error != 0) {
		relpbuf(bp, freecnt);
		return (VM_PAGER_ERROR);
	}

	/*
	 * If the file system supports BMAP, but blocksize is smaller
	 * than a page size, then use special small filesystem code.
	 */
	if (pagesperblock == 0) {
		relpbuf(bp, freecnt);
		for (i = 0; i < count; i++) {
			PCPU_INC(cnt.v_vnodein);
			PCPU_INC(cnt.v_vnodepgsin);
			error = vnode_pager_input_smlfs(object, m[i]);
			if (error)
				break;
		}
		return (error);
	}

	/*
	 * A sparse file can be encountered only for a single page request,
	 * which may not be preceded by call to vm_pager_haspage().
	 */
	if (bp->b_blkno == -1) {
		KASSERT(count == 1,
		    ("%s: array[%d] request to a sparse file %p", __func__,
		    count, vp));
		relpbuf(bp, freecnt);
		pmap_zero_page(m[0]);
		KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
		    __func__, m[0]));
		VM_OBJECT_WLOCK(object);
		m[0]->valid = VM_PAGE_BITS_ALL;
		VM_OBJECT_WUNLOCK(object);
		return (VM_PAGER_OK);
	}

#ifdef INVARIANTS
	blkno0 = bp->b_blkno;
#endif
	bp->b_blkno += (foff % bsize) / DEV_BSIZE;

	/* Recalculate blocks available after/before to pages. */
	poff = (foff % bsize) / PAGE_SIZE;
	before *= pagesperblock;
	before += poff;
	after *= pagesperblock;
	after += pagesperblock - (poff + 1);
	if (m[0]->pindex + after >= object->size)
		after = object->size - 1 - m[0]->pindex;
	KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
	    __func__, count, after + 1));
	after -= count - 1;

	/* Trim requested rbehind/rahead to possible values. */   
	rbehind = a_rbehind ? *a_rbehind : 0;
	rahead = a_rahead ? *a_rahead : 0;
	rbehind = min(rbehind, before);
	rbehind = min(rbehind, m[0]->pindex);
	rahead = min(rahead, after);
	rahead = min(rahead, object->size - m[count - 1]->pindex);
	/*
	 * Check that total amount of pages fit into buf.  Trim rbehind and
	 * rahead evenly if not.
	 */
	if (rbehind + rahead + count > nitems(bp->b_pages)) {
		int trim, sum;

		trim = rbehind + rahead + count - nitems(bp->b_pages) + 1;
		sum = rbehind + rahead;
		if (rbehind == before) {
			/* Roundup rbehind trim to block size. */
			rbehind -= roundup(trim * rbehind / sum, pagesperblock);
			if (rbehind < 0)
				rbehind = 0;
		} else
			rbehind -= trim * rbehind / sum;
		rahead -= trim * rahead / sum;
	}
	KASSERT(rbehind + rahead + count <= nitems(bp->b_pages),
	    ("%s: behind %d ahead %d count %d", __func__,
	    rbehind, rahead, count));

	/*
	 * Fill in the bp->b_pages[] array with requested and optional   
	 * read behind or read ahead pages.  Read behind pages are looked
	 * up in a backward direction, down to a first cached page.  Same
	 * for read ahead pages, but there is no need to shift the array
	 * in case of encountering a cached page.
	 */
	i = bp->b_npages = 0;
	if (rbehind) {
		vm_pindex_t startpindex, tpindex;
		vm_page_t p;

		VM_OBJECT_WLOCK(object);
		startpindex = m[0]->pindex - rbehind;
		if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
		    p->pindex >= startpindex)
			startpindex = p->pindex + 1;

		/* tpindex is unsigned; beware of numeric underflow. */
		for (tpindex = m[0]->pindex - 1;
		    tpindex >= startpindex && tpindex < m[0]->pindex;
		    tpindex--, i++) {
			p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
			if (p == NULL) {
				/* Shift the array. */
				for (int j = 0; j < i; j++)
					bp->b_pages[j] = bp->b_pages[j + 
					    tpindex + 1 - startpindex]; 
				break;
			}
			bp->b_pages[tpindex - startpindex] = p;
		}

		bp->b_pgbefore = i;
		bp->b_npages += i;
		bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
	} else
		bp->b_pgbefore = 0;

	/* Requested pages. */
	for (int j = 0; j < count; j++, i++)
		bp->b_pages[i] = m[j];
	bp->b_npages += count;

	if (rahead) {
		vm_pindex_t endpindex, tpindex;
		vm_page_t p;

		if (!VM_OBJECT_WOWNED(object))
			VM_OBJECT_WLOCK(object);
		endpindex = m[count - 1]->pindex + rahead + 1;
		if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
		    p->pindex < endpindex)
			endpindex = p->pindex;
		if (endpindex > object->size)
			endpindex = object->size;

		for (tpindex = m[count - 1]->pindex + 1;
		    tpindex < endpindex; i++, tpindex++) {
			p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
			if (p == NULL)
				break;
			bp->b_pages[i] = p;
		}

		bp->b_pgafter = i - bp->b_npages;
		bp->b_npages = i;
	} else
		bp->b_pgafter = 0;

	if (VM_OBJECT_WOWNED(object))
		VM_OBJECT_WUNLOCK(object);

	/* Report back actual behind/ahead read. */
	if (a_rbehind)
		*a_rbehind = bp->b_pgbefore;
	if (a_rahead)
		*a_rahead = bp->b_pgafter;

#ifdef INVARIANTS
	KASSERT(bp->b_npages <= nitems(bp->b_pages),
	    ("%s: buf %p overflowed", __func__, bp));
	for (int j = 1; j < bp->b_npages; j++)
		KASSERT(bp->b_pages[j]->pindex - 1 ==
		    bp->b_pages[j - 1]->pindex,
		    ("%s: pages array not consecutive, bp %p", __func__, bp));
#endif

	/*
	 * Recalculate first offset and bytecount with regards to read behind.
	 * Truncate bytecount to vnode real size and round up physical size
	 * for real devices.
	 */
	foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
	bytecount = bp->b_npages << PAGE_SHIFT;
	if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
		bytecount = object->un_pager.vnp.vnp_size - foff;
	secmask = bo->bo_bsize - 1;
	KASSERT(secmask < PAGE_SIZE && secmask > 0,
	    ("%s: sector size %d too large", __func__, secmask + 1));
	bytecount = (bytecount + secmask) & ~secmask;

	/*
	 * And map the pages to be read into the kva, if the filesystem
	 * requires mapped buffers.
	 */
	if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
	    unmapped_buf_allowed) {
		bp->b_data = unmapped_buf;
		bp->b_offset = 0;
	} else {
		bp->b_data = bp->b_kvabase;
		pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
	}

	/* Build a minimal buffer header. */
	bp->b_iocmd = BIO_READ;
	KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
	KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
	bp->b_rcred = crhold(curthread->td_ucred);
	bp->b_wcred = crhold(curthread->td_ucred);
	pbgetbo(bo, bp);
	bp->b_vp = vp;
	bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
	bp->b_iooffset = dbtob(bp->b_blkno);
	KASSERT(IDX_TO_OFF(m[0]->pindex - bp->b_pages[0]->pindex) ==
	    (blkno0 - bp->b_blkno) * DEV_BSIZE +
	    IDX_TO_OFF(m[0]->pindex) % bsize,
	    ("wrong offsets bsize %d m[0] %ju b_pages[0] %ju "
	    "blkno0 %ju b_blkno %ju", bsize,
	    (uintmax_t)m[0]->pindex, (uintmax_t)bp->b_pages[0]->pindex,
	    (uintmax_t)blkno0, (uintmax_t)bp->b_blkno));

	atomic_add_long(&runningbufspace, bp->b_runningbufspace);
	PCPU_INC(cnt.v_vnodein);
	PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages);

	if (iodone != NULL) { /* async */
		bp->b_pgiodone = iodone;
		bp->b_caller1 = arg;
		bp->b_iodone = vnode_pager_generic_getpages_done_async;
		bp->b_flags |= B_ASYNC;
		BUF_KERNPROC(bp);
		bstrategy(bp);
		return (VM_PAGER_OK);
	} else {
		bp->b_iodone = bdone;
		bstrategy(bp);
		bwait(bp, PVM, "vnread");
		error = vnode_pager_generic_getpages_done(bp);
		for (i = 0; i < bp->b_npages; i++)
			bp->b_pages[i] = NULL;
		bp->b_vp = NULL;
		pbrelbo(bp);
		relpbuf(bp, &vnode_pbuf_freecnt);
		return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
	}
}
Ejemplo n.º 4
0
/*
 * small block filesystem vnode pager input
 */
static int
vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
{
	struct vnode *vp;
	struct bufobj *bo;
	struct buf *bp;
	struct sf_buf *sf;
	daddr_t fileaddr;
	vm_offset_t bsize;
	vm_page_bits_t bits;
	int error, i;

	error = 0;
	vp = object->handle;
	if (vp->v_iflag & VI_DOOMED)
		return VM_PAGER_BAD;

	bsize = vp->v_mount->mnt_stat.f_iosize;

	VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);

	sf = sf_buf_alloc(m, 0);

	for (i = 0; i < PAGE_SIZE / bsize; i++) {
		vm_ooffset_t address;

		bits = vm_page_bits(i * bsize, bsize);
		if (m->valid & bits)
			continue;

		address = IDX_TO_OFF(m->pindex) + i * bsize;
		if (address >= object->un_pager.vnp.vnp_size) {
			fileaddr = -1;
		} else {
			error = vnode_pager_addr(vp, address, &fileaddr, NULL);
			if (error)
				break;
		}
		if (fileaddr != -1) {
			bp = getpbuf(&vnode_pbuf_freecnt);

			/* build a minimal buffer header */
			bp->b_iocmd = BIO_READ;
			bp->b_iodone = bdone;
			KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
			KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
			bp->b_rcred = crhold(curthread->td_ucred);
			bp->b_wcred = crhold(curthread->td_ucred);
			bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
			bp->b_blkno = fileaddr;
			pbgetbo(bo, bp);
			bp->b_vp = vp;
			bp->b_bcount = bsize;
			bp->b_bufsize = bsize;
			bp->b_runningbufspace = bp->b_bufsize;
			atomic_add_long(&runningbufspace, bp->b_runningbufspace);

			/* do the input */
			bp->b_iooffset = dbtob(bp->b_blkno);
			bstrategy(bp);

			bwait(bp, PVM, "vnsrd");

			if ((bp->b_ioflags & BIO_ERROR) != 0)
				error = EIO;

			/*
			 * free the buffer header back to the swap buffer pool
			 */
			bp->b_vp = NULL;
			pbrelbo(bp);
			relpbuf(bp, &vnode_pbuf_freecnt);
			if (error)
				break;
		} else
			bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
		KASSERT((m->dirty & bits) == 0,
		    ("vnode_pager_input_smlfs: page %p is dirty", m));
		VM_OBJECT_WLOCK(object);
		m->valid |= bits;
		VM_OBJECT_WUNLOCK(object);
	}
	sf_buf_free(sf);
	if (error) {
		return VM_PAGER_ERROR;
	}
	return VM_PAGER_OK;
}
Ejemplo n.º 5
0
/*
 * This is now called from local media FS's to operate against their
 * own vnodes if they fail to implement VOP_GETPAGES.
 */
int
vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int bytecount,
    int reqpage, vop_getpages_iodone_t iodone, void *arg)
{
	vm_object_t object;
	struct bufobj *bo;
	struct buf *bp;
	daddr_t firstaddr, reqblock;
	off_t foff, pib;
	int pbefore, pafter, i, size, bsize, first, last, *freecnt;
	int count, error, before, after, secmask;

	KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
	    ("vnode_pager_generic_getpages does not support devices"));
	if (vp->v_iflag & VI_DOOMED)
		return (VM_PAGER_BAD);

	object = vp->v_object;
	count = bytecount / PAGE_SIZE;
	bsize = vp->v_mount->mnt_stat.f_iosize;

	/*
	 * Synchronous and asynchronous paging operations use different
	 * free pbuf counters.  This is done to avoid asynchronous requests
	 * to consume all pbufs.
	 * Allocate the pbuf at the very beginning of the function, so that
	 * if we are low on certain kind of pbufs don't even proceed to BMAP,
	 * but sleep.
	 */
	freecnt = iodone != NULL ?
	    &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
	bp = getpbuf(freecnt);

	/*
	 * Get the underlying device blocks for the file with VOP_BMAP().
	 * If the file system doesn't support VOP_BMAP, use old way of
	 * getting pages via VOP_READ.
	 */
	error = VOP_BMAP(vp, IDX_TO_OFF(m[reqpage]->pindex) / bsize, &bo,
	    &reqblock, &after, &before);
	if (error == EOPNOTSUPP) {
		relpbuf(bp, freecnt);
		VM_OBJECT_WLOCK(object);
		for (i = 0; i < count; i++)
			if (i != reqpage) {
				vm_page_lock(m[i]);
				vm_page_free(m[i]);
				vm_page_unlock(m[i]);
			}
		PCPU_INC(cnt.v_vnodein);
		PCPU_INC(cnt.v_vnodepgsin);
		error = vnode_pager_input_old(object, m[reqpage]);
		VM_OBJECT_WUNLOCK(object);
		return (error);
	} else if (error != 0) {
		relpbuf(bp, freecnt);
		vm_pager_free_nonreq(object, m, reqpage, count, FALSE);
		return (VM_PAGER_ERROR);

		/*
		 * If the blocksize is smaller than a page size, then use
		 * special small filesystem code.
		 */
	} else if ((PAGE_SIZE / bsize) > 1) {
		relpbuf(bp, freecnt);
		vm_pager_free_nonreq(object, m, reqpage, count, FALSE);
		PCPU_INC(cnt.v_vnodein);
		PCPU_INC(cnt.v_vnodepgsin);
		return (vnode_pager_input_smlfs(object, m[reqpage]));
	}

	/*
	 * Since the caller has busied the requested page, that page's valid
	 * field will not be changed by other threads.
	 */
	vm_page_assert_xbusied(m[reqpage]);

	/*
	 * If we have a completely valid page available to us, we can
	 * clean up and return.  Otherwise we have to re-read the
	 * media.
	 */
	if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
		relpbuf(bp, freecnt);
		vm_pager_free_nonreq(object, m, reqpage, count, FALSE);
		return (VM_PAGER_OK);
	} else if (reqblock == -1) {
		relpbuf(bp, freecnt);
		pmap_zero_page(m[reqpage]);
		KASSERT(m[reqpage]->dirty == 0,
		    ("vnode_pager_generic_getpages: page %p is dirty", m));
		VM_OBJECT_WLOCK(object);
		m[reqpage]->valid = VM_PAGE_BITS_ALL;
		vm_pager_free_nonreq(object, m, reqpage, count, TRUE);
		VM_OBJECT_WUNLOCK(object);
		return (VM_PAGER_OK);
	} else if (m[reqpage]->valid != 0) {
		VM_OBJECT_WLOCK(object);
		m[reqpage]->valid = 0;
		VM_OBJECT_WUNLOCK(object);
	}

	pib = IDX_TO_OFF(m[reqpage]->pindex) % bsize;
	pbefore = ((daddr_t)before * bsize + pib) / PAGE_SIZE;
	pafter = ((daddr_t)(after + 1) * bsize - pib) / PAGE_SIZE - 1;
	first = reqpage < pbefore ? 0 : reqpage - pbefore;
	last = reqpage + pafter >= count ? count - 1 : reqpage + pafter;
	if (first > 0 || last + 1 < count) {
		VM_OBJECT_WLOCK(object);
		for (i = 0; i < first; i++) {
			vm_page_lock(m[i]);
			vm_page_free(m[i]);
			vm_page_unlock(m[i]);
		}
		for (i = last + 1; i < count; i++) {
			vm_page_lock(m[i]);
			vm_page_free(m[i]);
			vm_page_unlock(m[i]);
		}
		VM_OBJECT_WUNLOCK(object);
	}

	/*
	 * here on direct device I/O
	 */
	firstaddr = reqblock;
	firstaddr += pib / DEV_BSIZE;
	firstaddr -= IDX_TO_OFF(reqpage - first) / DEV_BSIZE;

	/*
	 * The first and last page have been calculated now, move
	 * input pages to be zero based, and adjust the count.
	 */
	m += first;
	reqpage -= first;
	count = last - first + 1;

	/*
	 * calculate the file virtual address for the transfer
	 */
	foff = IDX_TO_OFF(m[0]->pindex);

	/*
	 * calculate the size of the transfer
	 */
	size = count * PAGE_SIZE;
	KASSERT(count > 0, ("zero count"));
	if ((foff + size) > object->un_pager.vnp.vnp_size)
		size = object->un_pager.vnp.vnp_size - foff;
	KASSERT(size > 0, ("zero size"));

	/*
	 * round up physical size for real devices.
	 */
	secmask = bo->bo_bsize - 1;
	KASSERT(secmask < PAGE_SIZE && secmask > 0,
	    ("vnode_pager_generic_getpages: sector size %d too large",
	    secmask + 1));
	size = (size + secmask) & ~secmask;

	/*
	 * and map the pages to be read into the kva, if the filesystem
	 * requires mapped buffers.
	 */
	if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
	    unmapped_buf_allowed) {
		bp->b_data = unmapped_buf;
		bp->b_offset = 0;
	} else {
		bp->b_data = bp->b_kvabase;
		pmap_qenter((vm_offset_t)bp->b_data, m, count);
	}

	/* build a minimal buffer header */
	bp->b_iocmd = BIO_READ;
	KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
	KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
	bp->b_rcred = crhold(curthread->td_ucred);
	bp->b_wcred = crhold(curthread->td_ucred);
	bp->b_blkno = firstaddr;
	pbgetbo(bo, bp);
	bp->b_vp = vp;
	bp->b_bcount = size;
	bp->b_bufsize = size;
	bp->b_runningbufspace = bp->b_bufsize;
	for (i = 0; i < count; i++)
		bp->b_pages[i] = m[i];
	bp->b_npages = count;
	bp->b_pager.pg_reqpage = reqpage;
	atomic_add_long(&runningbufspace, bp->b_runningbufspace);

	PCPU_INC(cnt.v_vnodein);
	PCPU_ADD(cnt.v_vnodepgsin, count);

	/* do the input */
	bp->b_iooffset = dbtob(bp->b_blkno);

	if (iodone != NULL) { /* async */
		bp->b_pager.pg_iodone = iodone;
		bp->b_caller1 = arg;
		bp->b_iodone = vnode_pager_generic_getpages_done_async;
		bp->b_flags |= B_ASYNC;
		BUF_KERNPROC(bp);
		bstrategy(bp);
		/* Good bye! */
	} else {
		bp->b_iodone = bdone;
		bstrategy(bp);
		bwait(bp, PVM, "vnread");
		error = vnode_pager_generic_getpages_done(bp);
		for (i = 0; i < bp->b_npages; i++)
			bp->b_pages[i] = NULL;
		bp->b_vp = NULL;
		pbrelbo(bp);
		relpbuf(bp, &vnode_pbuf_freecnt);
	}

	return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
}