/* * 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 * $Id: vnode_pager.c,v 1.47 1995/09/06 05:37:41 dyson Exp $ */ /* * 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 struct pagerops vnodepagerops = { NULL, vnode_pager_alloc, vnode_pager_dealloc, vnode_pager_getpages, vnode_pager_putpages, vnode_pager_haspage, NULL }; static int vnode_pager_leaf_getpages(); static int vnode_pager_leaf_putpages(); /* * Allocate (or lookup) pager for a vnode. * Handle is a vnode pointer. */ vm_object_t vnode_pager_alloc(handle, size, prot, offset) void *handle; vm_size_t size; vm_prot_t prot; vm_offset_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; /* * Prevent race condition when allocating the object. This * can happen with NFS vnodes since the nfsnode isn't locked. */ while (vp->v_flag & VOLOCK) { vp->v_flag |= VOWANT; tsleep(vp, PVM, "vnpobj", 0); } vp->v_flag |= VOLOCK; /* * If the object is being terminated, wait for it to * go away. */ while (((object = vp->v_object) != NULL) && (object->flags & OBJ_DEAD)) { tsleep(object, PVM, "vadead", 0); } if (object == NULL) { /* * And an object of the appropriate size */ object = vm_object_allocate(OBJT_VNODE, round_page(size)); object->flags = OBJ_CANPERSIST; /* * Hold a reference to the vnode and initialize object data. */ VREF(vp); object->un_pager.vnp.vnp_size = size; object->handle = handle; vp->v_object = object; } else { /* * vm_object_reference() will remove the object from the cache if * found and gain a reference to the object. */ vm_object_reference(object); } if (vp->v_type == VREG) vp->v_flag |= VVMIO; vp->v_flag &= ~VOLOCK; if (vp->v_flag & VOWANT) { vp->v_flag &= ~VOWANT; wakeup(vp); } return (object); } void vnode_pager_dealloc(object) vm_object_t object; { register struct vnode *vp = object->handle; if (vp == NULL) panic("vnode_pager_dealloc: pager already dealloced"); if (object->paging_in_progress) { int s = splbio(); while (object->paging_in_progress) { object->flags |= OBJ_PIPWNT; tsleep(object, PVM, "vnpdea", 0); } splx(s); } object->handle = NULL; vp->v_object = NULL; vp->v_flag &= ~(VTEXT | VVMIO); vp->v_flag |= VAGE; vrele(vp); } boolean_t vnode_pager_haspage(object, offset, before, after) vm_object_t object; vm_offset_t offset; int *before; int *after; { struct vnode *vp = object->handle; daddr_t bn; int err, run; daddr_t reqblock; int poff; int bsize = vp->v_mount->mnt_stat.f_iosize; int pagesperblock; /* * If filesystem no longer mounted or offset beyond end of file we do * not have the page. */ if ((vp->v_mount == NULL) || (offset >= object->un_pager.vnp.vnp_size)) return FALSE; pagesperblock = bsize / PAGE_SIZE; reqblock = offset / bsize; err = VOP_BMAP(vp, reqblock, (struct vnode **) 0, &bn, after, before); if (err) return TRUE; if (((long) bn) < 0) return FALSE; poff = (offset - (reqblock * bsize)) / PAGE_SIZE; if (before) { *before *= pagesperblock; *before += poff; } if (after) { int numafter; *after *= pagesperblock; numafter = pagesperblock - (poff + 1); if (offset + numafter * PAGE_SIZE > object->un_pager.vnp.vnp_size) { numafter = (object->un_pager.vnp.vnp_size - offset)/PAGE_SIZE; } *after += numafter; } 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; u_long nsize; { vm_object_t object = vp->v_object; if (object == NULL) return; /* * Hasn't changed size */ if (nsize == object->un_pager.vnp.vnp_size) return; /* * File has shrunk. Toss any cached pages beyond the new EOF. */ if (nsize < object->un_pager.vnp.vnp_size) { if (round_page((vm_offset_t) nsize) < object->un_pager.vnp.vnp_size) { vm_object_page_remove(object, round_page((vm_offset_t) nsize), object->un_pager.vnp.vnp_size, FALSE); } /* * this gets rid of garbage at the end of a page that is now * only partially backed by the vnode... */ if (nsize & PAGE_MASK) { vm_offset_t kva; vm_page_t m; m = vm_page_lookup(object, trunc_page((vm_offset_t) nsize)); if (m) { kva = vm_pager_map_page(m); bzero((caddr_t) kva + (nsize & PAGE_MASK), round_page(nsize) - nsize); vm_pager_unmap_page(kva); } } } object->un_pager.vnp.vnp_size = (vm_offset_t) nsize; object->size = round_page(nsize); } void vnode_pager_umount(mp) register struct mount *mp; { struct vnode *vp, *nvp; loop: for (vp = mp->mnt_vnodelist.lh_first; vp != NULL; vp = nvp) { /* * Vnode can be reclaimed by getnewvnode() while we * traverse the list. */ if (vp->v_mount != mp) goto loop; /* * Save the next pointer now since uncaching may terminate the * object and render vnode invalid */ nvp = vp->v_mntvnodes.le_next; if (vp->v_object != NULL) { VOP_LOCK(vp); vnode_pager_uncache(vp); VOP_UNLOCK(vp); } } } /* * Remove vnode associated object from the object cache. * This routine must be called with the vnode locked. * * XXX unlock the vnode. * We must do this since uncaching the object may result in its * destruction which may initiate paging activity which may necessitate * re-locking the vnode. */ void vnode_pager_uncache(vp) struct vnode *vp; { vm_object_t object; /* * Not a mapped vnode */ object = vp->v_object; if (object == NULL) return; vm_object_reference(object); VOP_UNLOCK(vp); pager_cache(object, FALSE); VOP_LOCK(vp); return; } void vnode_pager_freepage(m) vm_page_t m; { PAGE_WAKEUP(m); vm_page_free(m); } /* * calculate the linear (byte) disk address of specified virtual * file address */ vm_offset_t vnode_pager_addr(vp, address, run) struct vnode *vp; vm_offset_t address; int *run; { int rtaddress; int bsize; vm_offset_t block; struct vnode *rtvp; int err; int vblock, voffset; if ((int) address < 0) 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 */ void vnode_pager_iodone(bp) struct buf *bp; { bp->b_flags |= B_DONE; wakeup(bp); } /* * small block file system vnode pager input */ 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; vp = object->handle; 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++) { if ((vm_page_bits(m->offset + i * bsize, bsize) & m->valid)) continue; fileaddr = vnode_pager_addr(vp, m->offset + i * bsize, (int *)0); if (fileaddr != -1) { bp = getpbuf(); /* build a minimal buffer header */ bp->b_flags = B_BUSY | B_READ | B_CALL; bp->b_iodone = vnode_pager_iodone; bp->b_proc = curproc; bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred; if (bp->b_rcred != NOCRED) crhold(bp->b_rcred); if (bp->b_wcred != NOCRED) crhold(bp->b_wcred); bp->b_un.b_addr = (caddr_t) kva + i * bsize; bp->b_blkno = fileaddr; pbgetvp(dp, bp); bp->b_bcount = bsize; bp->b_bufsize = bsize; /* do the input */ VOP_STRATEGY(bp); /* we definitely need to be at splbio here */ s = splbio(); while ((bp->b_flags & B_DONE) == 0) { tsleep(bp, PVM, "vnsrd", 0); } splx(s); if ((bp->b_flags & B_ERROR) != 0) error = EIO; /* * free the buffer header back to the swap buffer pool */ relpbuf(bp); if (error) break; vm_page_set_validclean(m, (i * bsize) & (PAGE_SIZE-1), bsize); } else { vm_page_set_validclean(m, (i * bsize) & (PAGE_SIZE-1), bsize); bzero((caddr_t) kva + i * bsize, bsize); } } vm_pager_unmap_page(kva); pmap_clear_modify(VM_PAGE_TO_PHYS(m)); m->flags &= ~PG_ZERO; if (error) { return VM_PAGER_ERROR; } return VM_PAGER_OK; } /* * old style vnode pager output routine */ 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; error = 0; /* * Return failure if beyond current EOF */ if (m->offset >= object->un_pager.vnp.vnp_size) { return VM_PAGER_BAD; } else { size = PAGE_SIZE; if (m->offset + size > object->un_pager.vnp.vnp_size) size = object->un_pager.vnp.vnp_size - m->offset; /* * Allocate a kernel virtual address and initialize so that * we can use VOP_READ/WRITE routines. */ kva = vm_pager_map_page(m); aiov.iov_base = (caddr_t) kva; aiov.iov_len = size; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = m->offset; auio.uio_segflg = UIO_SYSSPACE; auio.uio_rw = UIO_READ; auio.uio_resid = size; auio.uio_procp = (struct proc *) 0; error = VOP_READ(object->handle, &auio, 0, curproc->p_ucred); if (!error) { register 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); } pmap_clear_modify(VM_PAGE_TO_PHYS(m)); m->dirty = 0; m->flags &= ~PG_ZERO; return error ? VM_PAGER_ERROR : VM_PAGER_OK; } /* * generic vnode pager input routine */ 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; vp = object->handle; rtval = VOP_GETPAGES(vp, m, count, reqpage); if (rtval == EOPNOTSUPP) return vnode_pager_leaf_getpages(object, m, count, reqpage); else return rtval; } static int vnode_pager_leaf_getpages(object, m, count, reqpage) vm_object_t object; vm_page_t *m; int count; int reqpage; { vm_offset_t kva, foff; int i, size, bsize, first, firstaddr; struct vnode *dp, *vp; int runpg; int runend; struct buf *bp; int s; int error = 0; vp = object->handle; 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 = m[reqpage]->offset; /* * if we can't bmap, use old VOP code */ if (VOP_BMAP(vp, 0, &dp, 0, NULL, NULL)) { for (i = 0; i < count; i++) { if (i != reqpage) { vnode_pager_freepage(m[i]); } } 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 != MOUNT_NFS)) { for (i = 0; i < count; i++) { if (i != reqpage) { vnode_pager_freepage(m[i]); } } cnt.v_vnodein++; cnt.v_vnodepgsin++; return vnode_pager_input_smlfs(object, m[reqpage]); } /* * if ANY DEV_BSIZE blocks are valid on a large filesystem block * then, the entire page is valid -- */ if (m[reqpage]->valid) { m[reqpage]->valid = VM_PAGE_BITS_ALL; for (i = 0; i < count; i++) { if (i != reqpage) vnode_pager_freepage(m[i]); } return VM_PAGER_OK; } /* * 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, m[i]->offset, &runpg); if (firstaddr == -1) { if (i == reqpage && foff < object->un_pager.vnp.vnp_size) { panic("vnode_pager_putpages: unexpected missing page: firstaddr: %d, foff: %ld, vnp_size: %d", firstaddr, foff, object->un_pager.vnp.vnp_size); } vnode_pager_freepage(m[i]); runend = i + 1; first = runend; continue; } runend = i + runpg; if (runend <= reqpage) { int j; for (j = i; j < runend; j++) { vnode_pager_freepage(m[j]); } } else { if (runpg < (count - first)) { for (i = first + runpg; i < count; i++) vnode_pager_freepage(m[i]); 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 = m[0]->offset; /* * 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) size = (size + DEV_BSIZE - 1) & ~(DEV_BSIZE - 1); bp = getpbuf(); 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_flags = B_BUSY | B_READ | B_CALL; bp->b_iodone = vnode_pager_iodone; /* B_PHYS is not set, but it is nice to fill this in */ bp->b_proc = curproc; bp->b_rcred = bp->b_wcred = bp->b_proc->p_ucred; if (bp->b_rcred != NOCRED) crhold(bp->b_rcred); if (bp->b_wcred != NOCRED) crhold(bp->b_wcred); bp->b_blkno = firstaddr; pbgetvp(dp, bp); bp->b_bcount = size; bp->b_bufsize = size; cnt.v_vnodein++; cnt.v_vnodepgsin += count; /* do the input */ VOP_STRATEGY(bp); s = splbio(); /* we definitely need to be at splbio here */ while ((bp->b_flags & B_DONE) == 0) { tsleep(bp, PVM, "vnread", 0); } splx(s); if ((bp->b_flags & B_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); for (i = 0; i < count; i++) { pmap_clear_modify(VM_PAGE_TO_PHYS(m[i])); m[i]->dirty = 0; m[i]->valid = VM_PAGE_BITS_ALL; m[i]->flags &= ~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 emperical 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) { vm_page_deactivate(m[i]); PAGE_WAKEUP(m[i]); } else { vnode_pager_freepage(m[i]); } } } if (error) { printf("vnode_pager_getpages: I/O read error\n"); } return (error ? VM_PAGER_ERROR : VM_PAGER_OK); } int 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; vp = object->handle; rtval = VOP_PUTPAGES(vp, m, count, sync, rtvals); if (rtval == EOPNOTSUPP) return vnode_pager_leaf_putpages(object, m, count, sync, rtvals); else return rtval; } /* * generic vnode pager output routine */ static int vnode_pager_leaf_putpages(object, m, count, sync, rtvals) vm_object_t object; vm_page_t *m; int count; boolean_t sync; int *rtvals; { int i; struct vnode *vp; int maxsize, ncount; struct uio auio; struct iovec aiov; int error; vp = object->handle;; for (i = 0; i < count; i++) rtvals[i] = VM_PAGER_AGAIN; if ((int) m[0]->offset < 0) { printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%x(%x)\n", m[0]->offset, m[0]->dirty); rtvals[0] = VM_PAGER_BAD; return VM_PAGER_BAD; } maxsize = count * PAGE_SIZE; ncount = count; if (maxsize + m[0]->offset > object->un_pager.vnp.vnp_size) { if (object->un_pager.vnp.vnp_size > m[0]->offset) maxsize = object->un_pager.vnp.vnp_size - m[0]->offset; else maxsize = 0; ncount = (maxsize + PAGE_SIZE - 1) / PAGE_SIZE; if (ncount < count) { for (i = ncount; i < count; i++) { rtvals[i] = VM_PAGER_BAD; } if (ncount == 0) { printf("vnode_pager_putpages: write past end of file: %d, %d\n", m[0]->offset, object->un_pager.vnp.vnp_size); return rtvals[0]; } } } for (i = 0; i < count; i++) { m[i]->busy++; m[i]->flags &= ~PG_BUSY; } aiov.iov_base = (caddr_t) 0; aiov.iov_len = maxsize; auio.uio_iov = &aiov; auio.uio_iovcnt = 1; auio.uio_offset = m[0]->offset; auio.uio_segflg = UIO_NOCOPY; auio.uio_rw = UIO_WRITE; auio.uio_resid = maxsize; auio.uio_procp = (struct proc *) 0; error = VOP_WRITE(vp, &auio, IO_VMIO, curproc->p_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 %d\n", auio.uio_resid, m[0]->offset); } for (i = 0; i < count; i++) { m[i]->busy--; if (i < ncount) { rtvals[i] = VM_PAGER_OK; } if ((m[i]->busy == 0) && (m[i]->flags & PG_WANTED)) wakeup(m[i]); } return rtvals[0]; } struct vnode * vnode_pager_lock(object) vm_object_t object; { for (; object != NULL; object = object->backing_object) { if (object->type != OBJT_VNODE) continue; VOP_LOCK(object->handle); return object->handle; } return NULL; }