/* * Copyright (c) 1990 University of Utah. * Copyright (c) 1991 The Regents of the University of California. * All rights reserved. * Copyright (c) 1993, 1994 John S. Dyson * Copyright (c) 1995, David Greenman * * This code is derived from software contributed to Berkeley by * the Systems Programming Group of the University of Utah Computer * Science Department. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. * * from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91 * $FreeBSD$ */ /* * Page to/from files (vnodes). */ /* * TODO: * Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will * greatly re-simplify the vnode_pager. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include static void vnode_pager_init(void); static vm_offset_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, int *run); static void vnode_pager_iodone(struct buf *bp); static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m); static int vnode_pager_input_old(vm_object_t object, vm_page_t m); static void vnode_pager_dealloc(vm_object_t); static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int); static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *); static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); struct pagerops vnodepagerops = { vnode_pager_init, vnode_pager_alloc, vnode_pager_dealloc, vnode_pager_getpages, vnode_pager_putpages, vnode_pager_haspage, NULL }; int vnode_pbuf_freecnt; static void vnode_pager_init(void) { vnode_pbuf_freecnt = nswbuf / 2 + 1; } /* * Allocate (or lookup) pager for a vnode. * Handle is a vnode pointer. * * MPSAFE */ vm_object_t vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t offset) { vm_object_t object; struct vnode *vp; /* * Pageout to vnode, no can do yet. */ if (handle == NULL) return (NULL); vp = (struct vnode *) handle; ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc"); mtx_lock(&Giant); /* * Prevent race condition when allocating the object. This * can happen with NFS vnodes since the nfsnode isn't locked. */ VI_LOCK(vp); while (vp->v_iflag & VI_OLOCK) { vp->v_iflag |= VI_OWANT; msleep(vp, VI_MTX(vp), PVM, "vnpobj", 0); } vp->v_iflag |= VI_OLOCK; VI_UNLOCK(vp); /* * If the object is being terminated, wait for it to * go away. */ while ((object = vp->v_object) != NULL) { VM_OBJECT_LOCK(object); if ((object->flags & OBJ_DEAD) == 0) break; msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0); } if (vp->v_usecount == 0) panic("vnode_pager_alloc: no vnode reference"); if (object == NULL) { /* * And an object of the appropriate size */ object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size))); object->un_pager.vnp.vnp_size = size; object->handle = handle; vp->v_object = object; } else { object->ref_count++; VM_OBJECT_UNLOCK(object); } VI_LOCK(vp); vp->v_usecount++; vp->v_iflag &= ~VI_OLOCK; if (vp->v_iflag & VI_OWANT) { vp->v_iflag &= ~VI_OWANT; wakeup(vp); } VI_UNLOCK(vp); mtx_unlock(&Giant); return (object); } static void vnode_pager_dealloc(object) vm_object_t object; { struct vnode *vp = object->handle; GIANT_REQUIRED; if (vp == NULL) panic("vnode_pager_dealloc: pager already dealloced"); VM_OBJECT_LOCK(object); vm_object_pip_wait(object, "vnpdea"); VM_OBJECT_UNLOCK(object); object->handle = NULL; object->type = OBJT_DEAD; ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc"); vp->v_object = NULL; vp->v_vflag &= ~(VV_TEXT | VV_OBJBUF); } static boolean_t vnode_pager_haspage(object, pindex, before, after) vm_object_t object; vm_pindex_t pindex; int *before; int *after; { struct vnode *vp = object->handle; daddr_t bn; int err; daddr_t reqblock; int poff; int bsize; int pagesperblock, blocksperpage; GIANT_REQUIRED; /* * If no vp or vp is doomed or marked transparent to VM, we do not * have the page. */ if (vp == NULL) return FALSE; VI_LOCK(vp); if (vp->v_iflag & VI_DOOMED) { VI_UNLOCK(vp); return FALSE; } VI_UNLOCK(vp); /* * If filesystem no longer mounted or offset beyond end of file we do * not have the page. */ if ((vp->v_mount == NULL) || (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)) return FALSE; bsize = vp->v_mount->mnt_stat.f_iosize; pagesperblock = bsize / PAGE_SIZE; blocksperpage = 0; if (pagesperblock > 0) { reqblock = pindex / pagesperblock; } else { blocksperpage = (PAGE_SIZE / bsize); reqblock = pindex * blocksperpage; } err = VOP_BMAP(vp, reqblock, (struct vnode **) 0, &bn, after, before); if (err) return TRUE; if (bn == -1) return FALSE; if (pagesperblock > 0) { poff = pindex - (reqblock * pagesperblock); if (before) { *before *= pagesperblock; *before += poff; } if (after) { int numafter; *after *= pagesperblock; numafter = pagesperblock - (poff + 1); if (IDX_TO_OFF(pindex + numafter) > object->un_pager.vnp.vnp_size) { numafter = OFF_TO_IDX(object->un_pager.vnp.vnp_size) - pindex; } *after += numafter; } } else { if (before) { *before /= blocksperpage; } if (after) { *after /= blocksperpage; } } return TRUE; } /* * Lets the VM system know about a change in size for a file. * We adjust our own internal size and flush any cached pages in * the associated object that are affected by the size change. * * Note: this routine may be invoked as a result of a pager put * operation (possibly at object termination time), so we must be careful. */ void vnode_pager_setsize(vp, nsize) struct vnode *vp; vm_ooffset_t nsize; { vm_pindex_t nobjsize; vm_object_t object = vp->v_object; GIANT_REQUIRED; if (object == NULL) return; /* * Hasn't changed size */ if (nsize == object->un_pager.vnp.vnp_size) return; nobjsize = OFF_TO_IDX(nsize + PAGE_MASK); /* * File has shrunk. Toss any cached pages beyond the new EOF. */ if (nsize < object->un_pager.vnp.vnp_size) { if (nobjsize < object->size) { VM_OBJECT_LOCK(object); vm_object_page_remove(object, nobjsize, object->size, FALSE); VM_OBJECT_UNLOCK(object); } /* * this gets rid of garbage at the end of a page that is now * only partially backed by the vnode. * * XXX for some reason (I don't know yet), if we take a * completely invalid page and mark it partially valid * it can screw up NFS reads, so we don't allow the case. */ if (nsize & PAGE_MASK) { vm_page_t m; m = vm_page_lookup(object, OFF_TO_IDX(nsize)); if (m && m->valid) { int base = (int)nsize & PAGE_MASK; int size = PAGE_SIZE - base; /* * Clear out partial-page garbage in case * the page has been mapped. */ pmap_zero_page_area(m, base, size); vm_page_lock_queues(); /* * XXX work around SMP data integrity race * by unmapping the page from user processes. * The garbage we just cleared may be mapped * to a user process running on another cpu * and this code is not running through normal * I/O channels which handle SMP issues for * us, so unmap page to synchronize all cpus. * * XXX should vm_pager_unmap_page() have * dealt with this? */ pmap_remove_all(m); /* * Clear out partial-page dirty bits. This * has the side effect of setting the valid * bits, but that is ok. There are a bunch * of places in the VM system where we expected * m->dirty == VM_PAGE_BITS_ALL. The file EOF * case is one of them. If the page is still * partially dirty, make it fully dirty. * * note that we do not clear out the valid * bits. This would prevent bogus_page * replacement from working properly. */ vm_page_set_validclean(m, base, size); if (m->dirty != 0) m->dirty = VM_PAGE_BITS_ALL; vm_page_unlock_queues(); } } } object->un_pager.vnp.vnp_size = nsize; object->size = nobjsize; } /* * calculate the linear (byte) disk address of specified virtual * file address */ static vm_offset_t vnode_pager_addr(vp, address, run) struct vnode *vp; vm_ooffset_t address; int *run; { int rtaddress; int bsize; daddr_t block; struct vnode *rtvp; int err; daddr_t vblock; int voffset; GIANT_REQUIRED; if ((int) address < 0) return -1; if (vp->v_mount == NULL) return -1; bsize = vp->v_mount->mnt_stat.f_iosize; vblock = address / bsize; voffset = address % bsize; err = VOP_BMAP(vp, vblock, &rtvp, &block, run, NULL); if (err || (block == -1)) rtaddress = -1; else { rtaddress = block + voffset / DEV_BSIZE; if (run) { *run += 1; *run *= bsize/PAGE_SIZE; *run -= voffset/PAGE_SIZE; } } return rtaddress; } /* * interrupt routine for I/O completion */ static void vnode_pager_iodone(bp) struct buf *bp; { bp->b_flags |= B_DONE; wakeup(bp); } /* * small block filesystem vnode pager input */ static int vnode_pager_input_smlfs(object, m) vm_object_t object; vm_page_t m; { int i; int s; struct vnode *dp, *vp; struct buf *bp; vm_offset_t kva; int fileaddr; vm_offset_t bsize; int error = 0; GIANT_REQUIRED; vp = object->handle; if (vp->v_mount == NULL) return VM_PAGER_BAD; bsize = vp->v_mount->mnt_stat.f_iosize; VOP_BMAP(vp, 0, &dp, 0, NULL, NULL); kva = vm_pager_map_page(m); for (i = 0; i < PAGE_SIZE / bsize; i++) { vm_ooffset_t address; if (vm_page_bits(i * bsize, bsize) & m->valid) continue; address = IDX_TO_OFF(m->pindex) + i * bsize; if (address >= object->un_pager.vnp.vnp_size) { fileaddr = -1; } else { fileaddr = vnode_pager_addr(vp, address, NULL); } if (fileaddr != -1) { bp = getpbuf(&vnode_pbuf_freecnt); /* build a minimal buffer header */ bp->b_iocmd = BIO_READ; bp->b_iodone = vnode_pager_iodone; 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) kva + i * bsize; bp->b_blkno = fileaddr; pbgetvp(dp, bp); bp->b_bcount = bsize; bp->b_bufsize = bsize; bp->b_runningbufspace = bp->b_bufsize; runningbufspace += bp->b_runningbufspace; /* do the input */ VOP_SPECSTRATEGY(bp->b_vp, bp); /* we definitely need to be at splvm here */ s = splvm(); while ((bp->b_flags & B_DONE) == 0) { tsleep(bp, PVM, "vnsrd", 0); } splx(s); if ((bp->b_ioflags & BIO_ERROR) != 0) error = EIO; /* * free the buffer header back to the swap buffer pool */ relpbuf(bp, &vnode_pbuf_freecnt); if (error) break; vm_page_lock_queues(); vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); vm_page_unlock_queues(); } else { vm_page_lock_queues(); vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize); vm_page_unlock_queues(); bzero((caddr_t) kva + i * bsize, bsize); } } vm_pager_unmap_page(kva); vm_page_lock_queues(); pmap_clear_modify(m); vm_page_flag_clear(m, PG_ZERO); vm_page_unlock_queues(); if (error) { return VM_PAGER_ERROR; } return VM_PAGER_OK; } /* * old style vnode pager output routine */ static int vnode_pager_input_old(object, m) vm_object_t object; vm_page_t m; { struct uio auio; struct iovec aiov; int error; int size; vm_offset_t kva; struct vnode *vp; GIANT_REQUIRED; error = 0; /* * Return failure if beyond current EOF */ if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) { return VM_PAGER_BAD; } else { size = PAGE_SIZE; if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size) size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex); /* * Allocate a kernel virtual address and initialize so that * we can use VOP_READ/WRITE routines. */ kva = vm_pager_map_page(m); vp = object->handle; aiov.iov_base = (caddr_t) kva; aiov.iov_len = size; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = IDX_TO_OFF(m->pindex); auio.uio_segflg = UIO_SYSSPACE; auio.uio_rw = UIO_READ; auio.uio_resid = size; auio.uio_td = curthread; error = VOP_READ(vp, &auio, 0, curthread->td_ucred); if (!error) { int count = size - auio.uio_resid; if (count == 0) error = EINVAL; else if (count != PAGE_SIZE) bzero((caddr_t) kva + count, PAGE_SIZE - count); } vm_pager_unmap_page(kva); } vm_page_lock_queues(); pmap_clear_modify(m); vm_page_undirty(m); vm_page_flag_clear(m, PG_ZERO); if (!error) m->valid = VM_PAGE_BITS_ALL; vm_page_unlock_queues(); return error ? VM_PAGER_ERROR : VM_PAGER_OK; } /* * generic vnode pager input routine */ /* * Local media VFS's that do not implement their own VOP_GETPAGES * should have their VOP_GETPAGES call to vnode_pager_generic_getpages() * to implement the previous behaviour. * * All other FS's should use the bypass to get to the local media * backing vp's VOP_GETPAGES. */ static int vnode_pager_getpages(object, m, count, reqpage) vm_object_t object; vm_page_t *m; int count; int reqpage; { int rtval; struct vnode *vp; int bytes = count * PAGE_SIZE; GIANT_REQUIRED; vp = object->handle; rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0); KASSERT(rtval != EOPNOTSUPP, ("vnode_pager: FS getpages not implemented\n")); return rtval; } /* * 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(vp, m, bytecount, reqpage) struct vnode *vp; vm_page_t *m; int bytecount; int reqpage; { vm_object_t object; vm_offset_t kva; off_t foff, tfoff, nextoff; int i, j, size, bsize, first, firstaddr; struct vnode *dp; int runpg; int runend; struct buf *bp; int s; int count; int error = 0; GIANT_REQUIRED; object = vp->v_object; count = bytecount / PAGE_SIZE; if (vp->v_mount == NULL) return VM_PAGER_BAD; bsize = vp->v_mount->mnt_stat.f_iosize; /* get the UNDERLYING device for the file with VOP_BMAP() */ /* * originally, we did not check for an error return value -- assuming * an fs always has a bmap entry point -- that assumption is wrong!!! */ foff = IDX_TO_OFF(m[reqpage]->pindex); /* * if we can't bmap, use old VOP code */ if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) { vm_page_lock_queues(); for (i = 0; i < count; i++) if (i != reqpage) vm_page_free(m[i]); vm_page_unlock_queues(); cnt.v_vnodein++; cnt.v_vnodepgsin++; return vnode_pager_input_old(object, m[reqpage]); /* * if the blocksize is smaller than a page size, then use * special small filesystem code. NFS sometimes has a small * blocksize, but it can handle large reads itself. */ } else if ((PAGE_SIZE / bsize) > 1 && (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) { vm_page_lock_queues(); for (i = 0; i < count; i++) if (i != reqpage) vm_page_free(m[i]); vm_page_unlock_queues(); cnt.v_vnodein++; cnt.v_vnodepgsin++; return vnode_pager_input_smlfs(object, 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) { vm_page_lock_queues(); for (i = 0; i < count; i++) if (i != reqpage) vm_page_free(m[i]); vm_page_unlock_queues(); return VM_PAGER_OK; } m[reqpage]->valid = 0; /* * here on direct device I/O */ firstaddr = -1; /* * calculate the run that includes the required page */ for (first = 0, i = 0; i < count; i = runend) { firstaddr = vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &runpg); if (firstaddr == -1) { if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { panic("vnode_pager_getpages: unexpected missing page: firstaddr: %d, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx", firstaddr, (uintmax_t)(foff >> 32), (uintmax_t)foff, (uintmax_t) (object->un_pager.vnp.vnp_size >> 32), (uintmax_t)object->un_pager.vnp.vnp_size); } vm_page_lock_queues(); vm_page_free(m[i]); vm_page_unlock_queues(); runend = i + 1; first = runend; continue; } runend = i + runpg; if (runend <= reqpage) { vm_page_lock_queues(); for (j = i; j < runend; j++) vm_page_free(m[j]); vm_page_unlock_queues(); } else { if (runpg < (count - first)) { vm_page_lock_queues(); for (i = first + runpg; i < count; i++) vm_page_free(m[i]); vm_page_unlock_queues(); count = first + runpg; } break; } first = runend; } /* * the first and last page have been calculated now, move input pages * to be zero based... */ if (first != 0) { for (i = first; i < count; i++) { m[i - first] = m[i]; } count -= first; reqpage -= first; } /* * 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; if ((foff + size) > object->un_pager.vnp.vnp_size) size = object->un_pager.vnp.vnp_size - foff; /* * round up physical size for real devices. */ if (dp->v_type == VBLK || dp->v_type == VCHR) { int secmask = dp->v_rdev->si_bsize_phys - 1; KASSERT(secmask < PAGE_SIZE, ("vnode_pager_generic_getpages: sector size %d too large\n", secmask + 1)); size = (size + secmask) & ~secmask; } bp = getpbuf(&vnode_pbuf_freecnt); kva = (vm_offset_t) bp->b_data; /* * and map the pages to be read into the kva */ pmap_qenter(kva, m, count); /* build a minimal buffer header */ bp->b_iocmd = BIO_READ; bp->b_iodone = vnode_pager_iodone; /* B_PHYS is not set, but it is nice to fill this in */ 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; pbgetvp(dp, bp); bp->b_bcount = size; bp->b_bufsize = size; bp->b_runningbufspace = bp->b_bufsize; runningbufspace += bp->b_runningbufspace; cnt.v_vnodein++; cnt.v_vnodepgsin += count; /* do the input */ if (dp->v_type == VCHR) VOP_SPECSTRATEGY(bp->b_vp, bp); else VOP_STRATEGY(bp->b_vp, bp); s = splvm(); /* we definitely need to be at splvm here */ while ((bp->b_flags & B_DONE) == 0) { tsleep(bp, PVM, "vnread", 0); } splx(s); if ((bp->b_ioflags & BIO_ERROR) != 0) error = EIO; if (!error) { if (size != count * PAGE_SIZE) bzero((caddr_t) kva + size, PAGE_SIZE * count - size); } pmap_qremove(kva, count); /* * free the buffer header back to the swap buffer pool */ relpbuf(bp, &vnode_pbuf_freecnt); vm_page_lock_queues(); for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) { vm_page_t mt; nextoff = tfoff + PAGE_SIZE; mt = m[i]; if (nextoff <= object->un_pager.vnp.vnp_size) { /* * Read filled up entire page. */ mt->valid = VM_PAGE_BITS_ALL; vm_page_undirty(mt); /* should be an assert? XXX */ pmap_clear_modify(mt); } else { /* * Read did not fill up entire page. Since this * is getpages, the page may be mapped, so we have * to zero the invalid portions of the page even * though we aren't setting them valid. * * Currently we do not set the entire page valid, * we just try to clear the piece that we couldn't * read. */ vm_page_set_validclean(mt, 0, object->un_pager.vnp.vnp_size - tfoff); /* handled by vm_fault now */ /* vm_page_zero_invalid(mt, FALSE); */ } vm_page_flag_clear(mt, PG_ZERO); if (i != reqpage) { /* * whether or not to leave the page activated is up in * the air, but we should put the page on a page queue * somewhere. (it already is in the object). Result: * It appears that empirical results show that * deactivating pages is best. */ /* * just in case someone was asking for this page we * now tell them that it is ok to use */ if (!error) { if (mt->flags & PG_WANTED) vm_page_activate(mt); else vm_page_deactivate(mt); vm_page_wakeup(mt); } else { vm_page_free(mt); } } } vm_page_unlock_queues(); if (error) { printf("vnode_pager_getpages: I/O read error\n"); } return (error ? VM_PAGER_ERROR : VM_PAGER_OK); } /* * EOPNOTSUPP is no longer legal. For local media VFS's that do not * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to * vnode_pager_generic_putpages() to implement the previous behaviour. * * All other FS's should use the bypass to get to the local media * backing vp's VOP_PUTPAGES. */ static void vnode_pager_putpages(object, m, count, sync, rtvals) vm_object_t object; vm_page_t *m; int count; boolean_t sync; int *rtvals; { int rtval; struct vnode *vp; struct mount *mp; int bytes = count * PAGE_SIZE; GIANT_REQUIRED; /* * Force synchronous operation if we are extremely low on memory * to prevent a low-memory deadlock. VOP operations often need to * allocate more memory to initiate the I/O ( i.e. do a BMAP * operation ). The swapper handles the case by limiting the amount * of asynchronous I/O, but that sort of solution doesn't scale well * for the vnode pager without a lot of work. * * Also, the backing vnode's iodone routine may not wake the pageout * daemon up. This should be probably be addressed XXX. */ if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min) sync |= OBJPC_SYNC; /* * Call device-specific putpages function */ vp = object->handle; if (vp->v_type != VREG) mp = NULL; (void)vn_start_write(vp, &mp, V_WAIT); rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0); KASSERT(rtval != EOPNOTSUPP, ("vnode_pager: stale FS putpages\n")); vn_finished_write(mp); } /* * This is now called from local media FS's to operate against their * own vnodes if they fail to implement VOP_PUTPAGES. * * This is typically called indirectly via the pageout daemon and * clustering has already typically occured, so in general we ask the * underlying filesystem to write the data out asynchronously rather * then delayed. */ int vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals) struct vnode *vp; vm_page_t *m; int bytecount; int flags; int *rtvals; { int i; vm_object_t object; int count; int maxsize, ncount; vm_ooffset_t poffset; struct uio auio; struct iovec aiov; int error; int ioflags; GIANT_REQUIRED; object = vp->v_object; count = bytecount / PAGE_SIZE; for (i = 0; i < count; i++) rtvals[i] = VM_PAGER_AGAIN; if ((int) m[0]->pindex < 0) { printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%x)\n", (long)m[0]->pindex, m[0]->dirty); rtvals[0] = VM_PAGER_BAD; return VM_PAGER_BAD; } maxsize = count * PAGE_SIZE; ncount = count; poffset = IDX_TO_OFF(m[0]->pindex); /* * If the page-aligned write is larger then the actual file we * have to invalidate pages occuring beyond the file EOF. However, * there is an edge case where a file may not be page-aligned where * the last page is partially invalid. In this case the filesystem * may not properly clear the dirty bits for the entire page (which * could be VM_PAGE_BITS_ALL due to the page having been mmap()d). * With the page locked we are free to fix-up the dirty bits here. * * We do not under any circumstances truncate the valid bits, as * this will screw up bogus page replacement. */ if (maxsize + poffset > object->un_pager.vnp.vnp_size) { if (object->un_pager.vnp.vnp_size > poffset) { int pgoff; maxsize = object->un_pager.vnp.vnp_size - poffset; ncount = btoc(maxsize); if ((pgoff = (int)maxsize & PAGE_MASK) != 0) { vm_page_clear_dirty(m[ncount - 1], pgoff, PAGE_SIZE - pgoff); } } else { maxsize = 0; ncount = 0; } if (ncount < count) { for (i = ncount; i < count; i++) { rtvals[i] = VM_PAGER_BAD; } } } /* * pageouts are already clustered, use IO_ASYNC t o force a bawrite() * rather then a bdwrite() to prevent paging I/O from saturating * the buffer cache. Dummy-up the sequential heuristic to cause * large ranges to cluster. If neither IO_SYNC or IO_ASYNC is set, * the system decides how to cluster. */ ioflags = IO_VMIO; if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) ioflags |= IO_SYNC; else if ((flags & VM_PAGER_CLUSTER_OK) == 0) ioflags |= IO_ASYNC; ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0; ioflags |= IO_SEQMAX << IO_SEQSHIFT; aiov.iov_base = (caddr_t) 0; aiov.iov_len = maxsize; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = poffset; auio.uio_segflg = UIO_NOCOPY; auio.uio_rw = UIO_WRITE; auio.uio_resid = maxsize; auio.uio_td = (struct thread *) 0; error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred); cnt.v_vnodeout++; cnt.v_vnodepgsout += ncount; if (error) { printf("vnode_pager_putpages: I/O error %d\n", error); } if (auio.uio_resid) { printf("vnode_pager_putpages: residual I/O %d at %lu\n", auio.uio_resid, (u_long)m[0]->pindex); } for (i = 0; i < ncount; i++) { rtvals[i] = VM_PAGER_OK; } return rtvals[0]; } struct vnode * vnode_pager_lock(object) vm_object_t object; { struct thread *td = curthread; /* XXX */ GIANT_REQUIRED; for (; object != NULL; object = object->backing_object) { if (object->type != OBJT_VNODE) continue; if (object->flags & OBJ_DEAD) { return NULL; } /* XXX; If object->handle can change, we need to cache it. */ while (vget(object->handle, LK_NOPAUSE | LK_SHARED | LK_RETRY | LK_CANRECURSE, td)){ if ((object->flags & OBJ_DEAD) || (object->type != OBJT_VNODE)) return NULL; printf("vnode_pager_lock: retrying\n"); } return object->handle; } return NULL; }