sys/vm/vnode_pager.c

   1 /*-
   2  * Copyright (c) 1990 University of Utah.
   3  * Copyright (c) 1991 The Regents of the University of California.
   4  * All rights reserved.
   5  * Copyright (c) 1993, 1994 John S. Dyson
   6  * Copyright (c) 1995, David Greenman
   7  *
   8  * This code is derived from software contributed to Berkeley by
   9  * the Systems Programming Group of the University of Utah Computer
  10  * Science Department.
  11  *
  12  * Redistribution and use in source and binary forms, with or without
  13  * modification, are permitted provided that the following conditions
  14  * are met:
  15  * 1. Redistributions of source code must retain the above copyright
  16  *    notice, this list of conditions and the following disclaimer.
  17  * 2. Redistributions in binary form must reproduce the above copyright
  18  *    notice, this list of conditions and the following disclaimer in the
  19  *    documentation and/or other materials provided with the distribution.
  20  * 3. All advertising materials mentioning features or use of this software
  21  *    must display the following acknowledgement:
  22  *      This product includes software developed by the University of
  23  *      California, Berkeley and its contributors.
  24  * 4. Neither the name of the University nor the names of its contributors
  25  *    may be used to endorse or promote products derived from this software
  26  *    without specific prior written permission.
  27  *
  28  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  29  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  30  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  31  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  32  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  33  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  34  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  35  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  37  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  38  * SUCH DAMAGE.
  39  *
  40  *      from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
  41  */
  42
  43 /*
  44  * Page to/from files (vnodes).
  45  */
  46
  47 /*
  48  * TODO:
  49  *      Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
  50  *      greatly re-simplify the vnode_pager.
  51  */
  52
  53 #include <sys/cdefs.h>
  54 __FBSDID("$FreeBSD$");
  55
  56 #include <sys/param.h>
  57 #include <sys/systm.h>
  58 #include <sys/proc.h>
  59 #include <sys/vnode.h>
  60 #include <sys/mount.h>
  61 #include <sys/bio.h>
  62 #include <sys/buf.h>
  63 #include <sys/vmmeter.h>
  64 #include <sys/limits.h>
  65 #include <sys/conf.h>
  66 #include <sys/sf_buf.h>
  67
  68 #include <machine/atomic.h>
  69
  70 #include <vm/vm.h>
  71 #include <vm/vm_object.h>
  72 #include <vm/vm_page.h>
  73 #include <vm/vm_pager.h>
  74 #include <vm/vm_map.h>
  75 #include <vm/vnode_pager.h>
  76 #include <vm/vm_extern.h>
  77
  78 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
  79     daddr_t *rtaddress, int *run);
  80 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
  81 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
  82 static void vnode_pager_dealloc(vm_object_t);
  83 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
  84 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
  85 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  86 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  87     vm_ooffset_t, struct ucred *cred);
  88
  89 struct pagerops vnodepagerops = {
  90         .pgo_alloc =    vnode_pager_alloc,
  91         .pgo_dealloc =  vnode_pager_dealloc,
  92         .pgo_getpages = vnode_pager_getpages,
  93         .pgo_putpages = vnode_pager_putpages,
  94         .pgo_haspage =  vnode_pager_haspage,
  95 };
  96
  97 int vnode_pbuf_freecnt;
  98
  99 /* Create the VM system backing object for this vnode */
 100 int
 101 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
 102 {
 103         vm_object_t object;
 104         vm_ooffset_t size = isize;
 105         struct vattr va;
 106
 107         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
 108                 return (0);
 109
 110         while ((object = vp->v_object) != NULL) {
 111                 VM_OBJECT_LOCK(object);
 112                 if (!(object->flags & OBJ_DEAD)) {
 113                         VM_OBJECT_UNLOCK(object);
 114                         return (0);
 115                 }
 116                 VOP_UNLOCK(vp, 0);
 117                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 118                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0);
 119                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 120         }
 121
 122         if (size == 0) {
 123                 if (vn_isdisk(vp, NULL)) {
 124                         size = IDX_TO_OFF(INT_MAX);
 125                 } else {
 126                         if (VOP_GETATTR(vp, &va, td->td_ucred))
 127                                 return (0);
 128                         size = va.va_size;
 129                 }
 130         }
 131
 132         object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
 133         /*
 134          * Dereference the reference we just created.  This assumes
 135          * that the object is associated with the vp.
 136          */
 137         VM_OBJECT_LOCK(object);
 138         object->ref_count--;
 139         VM_OBJECT_UNLOCK(object);
 140         vrele(vp);
 141
 142         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
 143
 144         return (0);
 145 }
 146
 147 void
 148 vnode_destroy_vobject(struct vnode *vp)
 149 {
 150         struct vm_object *obj;
 151
 152         obj = vp->v_object;
 153         if (obj == NULL)
 154                 return;
 155         ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
 156         VM_OBJECT_LOCK(obj);
 157         if (obj->ref_count == 0) {
 158                 /*
 159                  * vclean() may be called twice. The first time
 160                  * removes the primary reference to the object,
 161                  * the second time goes one further and is a
 162                  * special-case to terminate the object.
 163                  *
 164                  * don't double-terminate the object
 165                  */
 166                 if ((obj->flags & OBJ_DEAD) == 0)
 167                         vm_object_terminate(obj);
 168                 else
 169                         VM_OBJECT_UNLOCK(obj);
 170         } else {
 171                 /*
 172                  * Woe to the process that tries to page now :-).
 173                  */
 174                 vm_pager_deallocate(obj);
 175                 VM_OBJECT_UNLOCK(obj);
 176         }
 177         vp->v_object = NULL;
 178 }
 179
 180
 181 /*
 182  * Allocate (or lookup) pager for a vnode.
 183  * Handle is a vnode pointer.
 184  *
 185  * MPSAFE
 186  */
 187 vm_object_t
 188 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 189     vm_ooffset_t offset, struct ucred *cred)
 190 {
 191         vm_object_t object;
 192         struct vnode *vp;
 193
 194         /*
 195          * Pageout to vnode, no can do yet.
 196          */
 197         if (handle == NULL)
 198                 return (NULL);
 199
 200         vp = (struct vnode *) handle;
 201
 202         /*
 203          * If the object is being terminated, wait for it to
 204          * go away.
 205          */
 206 retry:
 207         while ((object = vp->v_object) != NULL) {
 208                 VM_OBJECT_LOCK(object);
 209                 if ((object->flags & OBJ_DEAD) == 0)
 210                         break;
 211                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 212                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0);
 213         }
 214
 215         if (vp->v_usecount == 0)
 216                 panic("vnode_pager_alloc: no vnode reference");
 217
 218         if (object == NULL) {
 219                 /*
 220                  * Add an object of the appropriate size
 221                  */
 222                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 223
 224                 object->un_pager.vnp.vnp_size = size;
 225
 226                 object->handle = handle;
 227                 VI_LOCK(vp);
 228                 if (vp->v_object != NULL) {
 229                         /*
 230                          * Object has been created while we were sleeping
 231                          */
 232                         VI_UNLOCK(vp);
 233                         vm_object_destroy(object);
 234                         goto retry;
 235                 }
 236                 vp->v_object = object;
 237                 VI_UNLOCK(vp);
 238         } else {
 239                 object->ref_count++;
 240                 VM_OBJECT_UNLOCK(object);
 241         }
 242         vref(vp);
 243         return (object);
 244 }
 245
 246 /*
 247  *      The object must be locked.
 248  */
 249 static void
 250 vnode_pager_dealloc(object)
 251         vm_object_t object;
 252 {
 253         struct vnode *vp;
 254         int refs;
 255
 256         vp = object->handle;
 257         if (vp == NULL)
 258                 panic("vnode_pager_dealloc: pager already dealloced");
 259
 260         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 261         vm_object_pip_wait(object, "vnpdea");
 262         refs = object->ref_count;
 263
 264         object->handle = NULL;
 265         object->type = OBJT_DEAD;
 266         if (object->flags & OBJ_DISCONNECTWNT) {
 267                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 268                 wakeup(object);
 269         }
 270         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 271         vp->v_object = NULL;
 272         vp->v_vflag &= ~VV_TEXT;
 273         while (refs-- > 0)
 274                 vunref(vp);
 275 }
 276
 277 static boolean_t
 278 vnode_pager_haspage(object, pindex, before, after)
 279         vm_object_t object;
 280         vm_pindex_t pindex;
 281         int *before;
 282         int *after;
 283 {
 284         struct vnode *vp = object->handle;
 285         daddr_t bn;
 286         int err;
 287         daddr_t reqblock;
 288         int poff;
 289         int bsize;
 290         int pagesperblock, blocksperpage;
 291         int vfslocked;
 292
 293         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 294         /*
 295          * If no vp or vp is doomed or marked transparent to VM, we do not
 296          * have the page.
 297          */
 298         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 299                 return FALSE;
 300         /*
 301          * If the offset is beyond end of file we do
 302          * not have the page.
 303          */
 304         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 305                 return FALSE;
 306
 307         bsize = vp->v_mount->mnt_stat.f_iosize;
 308         pagesperblock = bsize / PAGE_SIZE;
 309         blocksperpage = 0;
 310         if (pagesperblock > 0) {
 311                 reqblock = pindex / pagesperblock;
 312         } else {
 313                 blocksperpage = (PAGE_SIZE / bsize);
 314                 reqblock = pindex * blocksperpage;
 315         }
 316         VM_OBJECT_UNLOCK(object);
 317         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 318         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 319         VFS_UNLOCK_GIANT(vfslocked);
 320         VM_OBJECT_LOCK(object);
 321         if (err)
 322                 return TRUE;
 323         if (bn == -1)
 324                 return FALSE;
 325         if (pagesperblock > 0) {
 326                 poff = pindex - (reqblock * pagesperblock);
 327                 if (before) {
 328                         *before *= pagesperblock;
 329                         *before += poff;
 330                 }
 331                 if (after) {
 332                         int numafter;
 333                         *after *= pagesperblock;
 334                         numafter = pagesperblock - (poff + 1);
 335                         if (IDX_TO_OFF(pindex + numafter) >
 336                             object->un_pager.vnp.vnp_size) {
 337                                 numafter =
 338                                     OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
 339                                     pindex;
 340                         }
 341                         *after += numafter;
 342                 }
 343         } else {
 344                 if (before) {
 345                         *before /= blocksperpage;
 346                 }
 347
 348                 if (after) {
 349                         *after /= blocksperpage;
 350                 }
 351         }
 352         return TRUE;
 353 }
 354
 355 /*
 356  * Lets the VM system know about a change in size for a file.
 357  * We adjust our own internal size and flush any cached pages in
 358  * the associated object that are affected by the size change.
 359  *
 360  * Note: this routine may be invoked as a result of a pager put
 361  * operation (possibly at object termination time), so we must be careful.
 362  */
 363 void
 364 vnode_pager_setsize(vp, nsize)
 365         struct vnode *vp;
 366         vm_ooffset_t nsize;
 367 {
 368         vm_object_t object;
 369         vm_page_t m;
 370         vm_pindex_t nobjsize;
 371
 372         if ((object = vp->v_object) == NULL)
 373                 return;
 374 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 375         VM_OBJECT_LOCK(object);
 376         if (nsize == object->un_pager.vnp.vnp_size) {
 377                 /*
 378                  * Hasn't changed size
 379                  */
 380                 VM_OBJECT_UNLOCK(object);
 381                 return;
 382         }
 383         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 384         if (nsize < object->un_pager.vnp.vnp_size) {
 385                 /*
 386                  * File has shrunk. Toss any cached pages beyond the new EOF.
 387                  */
 388                 if (nobjsize < object->size)
 389                         vm_object_page_remove(object, nobjsize, object->size,
 390                             FALSE);
 391                 /*
 392                  * this gets rid of garbage at the end of a page that is now
 393                  * only partially backed by the vnode.
 394                  *
 395                  * XXX for some reason (I don't know yet), if we take a
 396                  * completely invalid page and mark it partially valid
 397                  * it can screw up NFS reads, so we don't allow the case.
 398                  */
 399                 if ((nsize & PAGE_MASK) &&
 400                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 401                     m->valid != 0) {
 402                         int base = (int)nsize & PAGE_MASK;
 403                         int size = PAGE_SIZE - base;
 404
 405                         /*
 406                          * Clear out partial-page garbage in case
 407                          * the page has been mapped.
 408                          */
 409                         pmap_zero_page_area(m, base, size);
 410
 411                         /*
 412                          * Update the valid bits to reflect the blocks that
 413                          * have been zeroed.  Some of these valid bits may
 414                          * have already been set.
 415                          */
 416                         vm_page_set_valid(m, base, size);
 417
 418                         /*
 419                          * Round "base" to the next block boundary so that the
 420                          * dirty bit for a partially zeroed block is not
 421                          * cleared.
 422                          */
 423                         base = roundup2(base, DEV_BSIZE);
 424
 425                         /*
 426                          * Clear out partial-page dirty bits.
 427                          *
 428                          * note that we do not clear out the valid
 429                          * bits.  This would prevent bogus_page
 430                          * replacement from working properly.
 431                          */
 432                         vm_page_lock_queues();
 433                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 434                         vm_page_unlock_queues();
 435                 } else if ((nsize & PAGE_MASK) &&
 436                     __predict_false(object->cache != NULL)) {
 437                         vm_page_cache_free(object, OFF_TO_IDX(nsize),
 438                             nobjsize);
 439                 }
 440         }
 441         object->un_pager.vnp.vnp_size = nsize;
 442         object->size = nobjsize;
 443         VM_OBJECT_UNLOCK(object);
 444 }
 445
 446 /*
 447  * calculate the linear (byte) disk address of specified virtual
 448  * file address
 449  */
 450 static int
 451 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 452     int *run)
 453 {
 454         int bsize;
 455         int err;
 456         daddr_t vblock;
 457         daddr_t voffset;
 458
 459         if (address < 0)
 460                 return -1;
 461
 462         if (vp->v_iflag & VI_DOOMED)
 463                 return -1;
 464
 465         bsize = vp->v_mount->mnt_stat.f_iosize;
 466         vblock = address / bsize;
 467         voffset = address % bsize;
 468
 469         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 470         if (err == 0) {
 471                 if (*rtaddress != -1)
 472                         *rtaddress += voffset / DEV_BSIZE;
 473                 if (run) {
 474                         *run += 1;
 475                         *run *= bsize/PAGE_SIZE;
 476                         *run -= voffset/PAGE_SIZE;
 477                 }
 478         }
 479
 480         return (err);
 481 }
 482
 483 /*
 484  * small block filesystem vnode pager input
 485  */
 486 static int
 487 vnode_pager_input_smlfs(object, m)
 488         vm_object_t object;
 489         vm_page_t m;
 490 {
 491         int bits, i;
 492         struct vnode *vp;
 493         struct bufobj *bo;
 494         struct buf *bp;
 495         struct sf_buf *sf;
 496         daddr_t fileaddr;
 497         vm_offset_t bsize;
 498         int error = 0;
 499
 500         vp = object->handle;
 501         if (vp->v_iflag & VI_DOOMED)
 502                 return VM_PAGER_BAD;
 503
 504         bsize = vp->v_mount->mnt_stat.f_iosize;
 505
 506         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 507
 508         sf = sf_buf_alloc(m, 0);
 509
 510         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 511                 vm_ooffset_t address;
 512
 513                 bits = vm_page_bits(i * bsize, bsize);
 514                 if (m->valid & bits)
 515                         continue;
 516
 517                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 518                 if (address >= object->un_pager.vnp.vnp_size) {
 519                         fileaddr = -1;
 520                 } else {
 521                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 522                         if (error)
 523                                 break;
 524                 }
 525                 if (fileaddr != -1) {
 526                         bp = getpbuf(&vnode_pbuf_freecnt);
 527
 528                         /* build a minimal buffer header */
 529                         bp->b_iocmd = BIO_READ;
 530                         bp->b_iodone = bdone;
 531                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 532                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 533                         bp->b_rcred = crhold(curthread->td_ucred);
 534                         bp->b_wcred = crhold(curthread->td_ucred);
 535                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 536                         bp->b_blkno = fileaddr;
 537                         pbgetbo(bo, bp);
 538                         bp->b_bcount = bsize;
 539                         bp->b_bufsize = bsize;
 540                         bp->b_runningbufspace = bp->b_bufsize;
 541                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 542
 543                         /* do the input */
 544                         bp->b_iooffset = dbtob(bp->b_blkno);
 545                         bstrategy(bp);
 546
 547                         bwait(bp, PVM, "vnsrd");
 548
 549                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 550                                 error = EIO;
 551
 552                         /*
 553                          * free the buffer header back to the swap buffer pool
 554                          */
 555                         pbrelbo(bp);
 556                         relpbuf(bp, &vnode_pbuf_freecnt);
 557                         if (error)
 558                                 break;
 559                 } else
 560                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 561                 KASSERT((m->dirty & bits) == 0,
 562                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 563                 VM_OBJECT_LOCK(object);
 564                 m->valid |= bits;
 565                 VM_OBJECT_UNLOCK(object);
 566         }
 567         sf_buf_free(sf);
 568         if (error) {
 569                 return VM_PAGER_ERROR;
 570         }
 571         return VM_PAGER_OK;
 572 }
 573
 574 /*
 575  * old style vnode pager input routine
 576  */
 577 static int
 578 vnode_pager_input_old(object, m)
 579         vm_object_t object;
 580         vm_page_t m;
 581 {
 582         struct uio auio;
 583         struct iovec aiov;
 584         int error;
 585         int size;
 586         struct sf_buf *sf;
 587         struct vnode *vp;
 588
 589         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 590         error = 0;
 591
 592         /*
 593          * Return failure if beyond current EOF
 594          */
 595         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 596                 return VM_PAGER_BAD;
 597         } else {
 598                 size = PAGE_SIZE;
 599                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 600                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 601                 vp = object->handle;
 602                 VM_OBJECT_UNLOCK(object);
 603
 604                 /*
 605                  * Allocate a kernel virtual address and initialize so that
 606                  * we can use VOP_READ/WRITE routines.
 607                  */
 608                 sf = sf_buf_alloc(m, 0);
 609
 610                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 611                 aiov.iov_len = size;
 612                 auio.uio_iov = &aiov;
 613                 auio.uio_iovcnt = 1;
 614                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 615                 auio.uio_segflg = UIO_SYSSPACE;
 616                 auio.uio_rw = UIO_READ;
 617                 auio.uio_resid = size;
 618                 auio.uio_td = curthread;
 619
 620                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 621                 if (!error) {
 622                         int count = size - auio.uio_resid;
 623
 624                         if (count == 0)
 625                                 error = EINVAL;
 626                         else if (count != PAGE_SIZE)
 627                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 628                                     PAGE_SIZE - count);
 629                 }
 630                 sf_buf_free(sf);
 631
 632                 VM_OBJECT_LOCK(object);
 633         }
 634         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 635         if (!error)
 636                 m->valid = VM_PAGE_BITS_ALL;
 637         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 638 }
 639
 640 /*
 641  * generic vnode pager input routine
 642  */
 643
 644 /*
 645  * Local media VFS's that do not implement their own VOP_GETPAGES
 646  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 647  * to implement the previous behaviour.
 648  *
 649  * All other FS's should use the bypass to get to the local media
 650  * backing vp's VOP_GETPAGES.
 651  */
 652 static int
 653 vnode_pager_getpages(object, m, count, reqpage)
 654         vm_object_t object;
 655         vm_page_t *m;
 656         int count;
 657         int reqpage;
 658 {
 659         int rtval;
 660         struct vnode *vp;
 661         int bytes = count * PAGE_SIZE;
 662         int vfslocked;
 663
 664         vp = object->handle;
 665         VM_OBJECT_UNLOCK(object);
 666         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 667         rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
 668         KASSERT(rtval != EOPNOTSUPP,
 669             ("vnode_pager: FS getpages not implemented\n"));
 670         VFS_UNLOCK_GIANT(vfslocked);
 671         VM_OBJECT_LOCK(object);
 672         return rtval;
 673 }
 674
 675 /*
 676  * This is now called from local media FS's to operate against their
 677  * own vnodes if they fail to implement VOP_GETPAGES.
 678  */
 679 int
 680 vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
 681         struct vnode *vp;
 682         vm_page_t *m;
 683         int bytecount;
 684         int reqpage;
 685 {
 686         vm_object_t object;
 687         vm_offset_t kva;
 688         off_t foff, tfoff, nextoff;
 689         int i, j, size, bsize, first;
 690         daddr_t firstaddr, reqblock;
 691         struct bufobj *bo;
 692         int runpg;
 693         int runend;
 694         struct buf *bp;
 695         int count;
 696         int error;
 697
 698         object = vp->v_object;
 699         count = bytecount / PAGE_SIZE;
 700
 701         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 702             ("vnode_pager_generic_getpages does not support devices"));
 703         if (vp->v_iflag & VI_DOOMED)
 704                 return VM_PAGER_BAD;
 705
 706         bsize = vp->v_mount->mnt_stat.f_iosize;
 707
 708         /* get the UNDERLYING device for the file with VOP_BMAP() */
 709
 710         /*
 711          * originally, we did not check for an error return value -- assuming
 712          * an fs always has a bmap entry point -- that assumption is wrong!!!
 713          */
 714         foff = IDX_TO_OFF(m[reqpage]->pindex);
 715
 716         /*
 717          * if we can't bmap, use old VOP code
 718          */
 719         error = VOP_BMAP(vp, foff / bsize, &bo, &reqblock, NULL, NULL);
 720         if (error == EOPNOTSUPP) {
 721                 VM_OBJECT_LOCK(object);
 722                 vm_page_lock_queues();
 723                 for (i = 0; i < count; i++)
 724                         if (i != reqpage)
 725                                 vm_page_free(m[i]);
 726                 vm_page_unlock_queues();
 727                 PCPU_INC(cnt.v_vnodein);
 728                 PCPU_INC(cnt.v_vnodepgsin);
 729                 error = vnode_pager_input_old(object, m[reqpage]);
 730                 VM_OBJECT_UNLOCK(object);
 731                 return (error);
 732         } else if (error != 0) {
 733                 VM_OBJECT_LOCK(object);
 734                 vm_page_lock_queues();
 735                 for (i = 0; i < count; i++)
 736                         if (i != reqpage)
 737                                 vm_page_free(m[i]);
 738                 vm_page_unlock_queues();
 739                 VM_OBJECT_UNLOCK(object);
 740                 return (VM_PAGER_ERROR);
 741
 742                 /*
 743                  * if the blocksize is smaller than a page size, then use
 744                  * special small filesystem code.  NFS sometimes has a small
 745                  * blocksize, but it can handle large reads itself.
 746                  */
 747         } else if ((PAGE_SIZE / bsize) > 1 &&
 748             (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
 749                 VM_OBJECT_LOCK(object);
 750                 vm_page_lock_queues();
 751                 for (i = 0; i < count; i++)
 752                         if (i != reqpage)
 753                                 vm_page_free(m[i]);
 754                 vm_page_unlock_queues();
 755                 VM_OBJECT_UNLOCK(object);
 756                 PCPU_INC(cnt.v_vnodein);
 757                 PCPU_INC(cnt.v_vnodepgsin);
 758                 return vnode_pager_input_smlfs(object, m[reqpage]);
 759         }
 760
 761         /*
 762          * If we have a completely valid page available to us, we can
 763          * clean up and return.  Otherwise we have to re-read the
 764          * media.
 765          */
 766         VM_OBJECT_LOCK(object);
 767         if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
 768                 vm_page_lock_queues();
 769                 for (i = 0; i < count; i++)
 770                         if (i != reqpage)
 771                                 vm_page_free(m[i]);
 772                 vm_page_unlock_queues();
 773                 VM_OBJECT_UNLOCK(object);
 774                 return VM_PAGER_OK;
 775         } else if (reqblock == -1) {
 776                 pmap_zero_page(m[reqpage]);
 777                 KASSERT(m[reqpage]->dirty == 0,
 778                     ("vnode_pager_generic_getpages: page %p is dirty", m));
 779                 m[reqpage]->valid = VM_PAGE_BITS_ALL;
 780                 vm_page_lock_queues();
 781                 for (i = 0; i < count; i++)
 782                         if (i != reqpage)
 783                                 vm_page_free(m[i]);
 784                 vm_page_unlock_queues();
 785                 VM_OBJECT_UNLOCK(object);
 786                 return (VM_PAGER_OK);
 787         }
 788         m[reqpage]->valid = 0;
 789         VM_OBJECT_UNLOCK(object);
 790
 791         /*
 792          * here on direct device I/O
 793          */
 794         firstaddr = -1;
 795
 796         /*
 797          * calculate the run that includes the required page
 798          */
 799         for (first = 0, i = 0; i < count; i = runend) {
 800                 if (vnode_pager_addr(vp, IDX_TO_OFF(m[i]->pindex), &firstaddr,
 801                     &runpg) != 0) {
 802                         VM_OBJECT_LOCK(object);
 803                         vm_page_lock_queues();
 804                         for (; i < count; i++)
 805                                 if (i != reqpage)
 806                                         vm_page_free(m[i]);
 807                         vm_page_unlock_queues();
 808                         VM_OBJECT_UNLOCK(object);
 809                         return (VM_PAGER_ERROR);
 810                 }
 811                 if (firstaddr == -1) {
 812                         VM_OBJECT_LOCK(object);
 813                         if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
 814                                 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
 815                                     (intmax_t)firstaddr, (uintmax_t)(foff >> 32),
 816                                     (uintmax_t)foff,
 817                                     (uintmax_t)
 818                                     (object->un_pager.vnp.vnp_size >> 32),
 819                                     (uintmax_t)object->un_pager.vnp.vnp_size);
 820                         }
 821                         vm_page_lock_queues();
 822                         vm_page_free(m[i]);
 823                         vm_page_unlock_queues();
 824                         VM_OBJECT_UNLOCK(object);
 825                         runend = i + 1;
 826                         first = runend;
 827                         continue;
 828                 }
 829                 runend = i + runpg;
 830                 if (runend <= reqpage) {
 831                         VM_OBJECT_LOCK(object);
 832                         vm_page_lock_queues();
 833                         for (j = i; j < runend; j++)
 834                                 vm_page_free(m[j]);
 835                         vm_page_unlock_queues();
 836                         VM_OBJECT_UNLOCK(object);
 837                 } else {
 838                         if (runpg < (count - first)) {
 839                                 VM_OBJECT_LOCK(object);
 840                                 vm_page_lock_queues();
 841                                 for (i = first + runpg; i < count; i++)
 842                                         vm_page_free(m[i]);
 843                                 vm_page_unlock_queues();
 844                                 VM_OBJECT_UNLOCK(object);
 845                                 count = first + runpg;
 846                         }
 847                         break;
 848                 }
 849                 first = runend;
 850         }
 851
 852         /*
 853          * the first and last page have been calculated now, move input pages
 854          * to be zero based...
 855          */
 856         if (first != 0) {
 857                 m += first;
 858                 count -= first;
 859                 reqpage -= first;
 860         }
 861
 862         /*
 863          * calculate the file virtual address for the transfer
 864          */
 865         foff = IDX_TO_OFF(m[0]->pindex);
 866
 867         /*
 868          * calculate the size of the transfer
 869          */
 870         size = count * PAGE_SIZE;
 871         KASSERT(count > 0, ("zero count"));
 872         if ((foff + size) > object->un_pager.vnp.vnp_size)
 873                 size = object->un_pager.vnp.vnp_size - foff;
 874         KASSERT(size > 0, ("zero size"));
 875
 876         /*
 877          * round up physical size for real devices.
 878          */
 879         if (1) {
 880                 int secmask = bo->bo_bsize - 1;
 881                 KASSERT(secmask < PAGE_SIZE && secmask > 0,
 882                     ("vnode_pager_generic_getpages: sector size %d too large",
 883                     secmask + 1));
 884                 size = (size + secmask) & ~secmask;
 885         }
 886
 887         bp = getpbuf(&vnode_pbuf_freecnt);
 888         kva = (vm_offset_t) bp->b_data;
 889
 890         /*
 891          * and map the pages to be read into the kva
 892          */
 893         pmap_qenter(kva, m, count);
 894
 895         /* build a minimal buffer header */
 896         bp->b_iocmd = BIO_READ;
 897         bp->b_iodone = bdone;
 898         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 899         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 900         bp->b_rcred = crhold(curthread->td_ucred);
 901         bp->b_wcred = crhold(curthread->td_ucred);
 902         bp->b_blkno = firstaddr;
 903         pbgetbo(bo, bp);
 904         bp->b_bcount = size;
 905         bp->b_bufsize = size;
 906         bp->b_runningbufspace = bp->b_bufsize;
 907         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 908
 909         PCPU_INC(cnt.v_vnodein);
 910         PCPU_ADD(cnt.v_vnodepgsin, count);
 911
 912         /* do the input */
 913         bp->b_iooffset = dbtob(bp->b_blkno);
 914         bstrategy(bp);
 915
 916         bwait(bp, PVM, "vnread");
 917
 918         if ((bp->b_ioflags & BIO_ERROR) != 0)
 919                 error = EIO;
 920
 921         if (!error) {
 922                 if (size != count * PAGE_SIZE)
 923                         bzero((caddr_t) kva + size, PAGE_SIZE * count - size);
 924         }
 925         pmap_qremove(kva, count);
 926
 927         /*
 928          * free the buffer header back to the swap buffer pool
 929          */
 930         pbrelbo(bp);
 931         relpbuf(bp, &vnode_pbuf_freecnt);
 932
 933         VM_OBJECT_LOCK(object);
 934         vm_page_lock_queues();
 935         for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
 936                 vm_page_t mt;
 937
 938                 nextoff = tfoff + PAGE_SIZE;
 939                 mt = m[i];
 940
 941                 if (nextoff <= object->un_pager.vnp.vnp_size) {
 942                         /*
 943                          * Read filled up entire page.
 944                          */
 945                         mt->valid = VM_PAGE_BITS_ALL;
 946                         KASSERT(mt->dirty == 0,
 947                             ("vnode_pager_generic_getpages: page %p is dirty",
 948                             mt));
 949                         KASSERT(!pmap_page_is_mapped(mt),
 950                             ("vnode_pager_generic_getpages: page %p is mapped",
 951                             mt));
 952                 } else {
 953                         /*
 954                          * Read did not fill up entire page.
 955                          *
 956                          * Currently we do not set the entire page valid,
 957                          * we just try to clear the piece that we couldn't
 958                          * read.
 959                          */
 960                         vm_page_set_valid(mt, 0,
 961                             object->un_pager.vnp.vnp_size - tfoff);
 962                         KASSERT((mt->dirty & vm_page_bits(0,
 963                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
 964                             ("vnode_pager_generic_getpages: page %p is dirty",
 965                             mt));
 966                 }
 967
 968                 if (i != reqpage) {
 969
 970                         /*
 971                          * whether or not to leave the page activated is up in
 972                          * the air, but we should put the page on a page queue
 973                          * somewhere. (it already is in the object). Result:
 974                          * It appears that empirical results show that
 975                          * deactivating pages is best.
 976                          */
 977
 978                         /*
 979                          * just in case someone was asking for this page we
 980                          * now tell them that it is ok to use
 981                          */
 982                         if (!error) {
 983                                 if (mt->oflags & VPO_WANTED)
 984                                         vm_page_activate(mt);
 985                                 else
 986                                         vm_page_deactivate(mt);
 987                                 vm_page_wakeup(mt);
 988                         } else {
 989                                 vm_page_free(mt);
 990                         }
 991                 }
 992         }
 993         vm_page_unlock_queues();
 994         VM_OBJECT_UNLOCK(object);
 995         if (error) {
 996                 printf("vnode_pager_getpages: I/O read error\n");
 997         }
 998         return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
 999 }
1000
1001 /*
1002  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1003  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1004  * vnode_pager_generic_putpages() to implement the previous behaviour.
1005  *
1006  * All other FS's should use the bypass to get to the local media
1007  * backing vp's VOP_PUTPAGES.
1008  */
1009 static void
1010 vnode_pager_putpages(object, m, count, sync, rtvals)
1011         vm_object_t object;
1012         vm_page_t *m;
1013         int count;
1014         boolean_t sync;
1015         int *rtvals;
1016 {
1017         int rtval;
1018         struct vnode *vp;
1019         int bytes = count * PAGE_SIZE;
1020
1021         /*
1022          * Force synchronous operation if we are extremely low on memory
1023          * to prevent a low-memory deadlock.  VOP operations often need to
1024          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1025          * operation ).  The swapper handles the case by limiting the amount
1026          * of asynchronous I/O, but that sort of solution doesn't scale well
1027          * for the vnode pager without a lot of work.
1028          *
1029          * Also, the backing vnode's iodone routine may not wake the pageout
1030          * daemon up.  This should be probably be addressed XXX.
1031          */
1032
1033         if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)
1034                 sync |= OBJPC_SYNC;
1035
1036         /*
1037          * Call device-specific putpages function
1038          */
1039         vp = object->handle;
1040         VM_OBJECT_UNLOCK(object);
1041         rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
1042         KASSERT(rtval != EOPNOTSUPP,
1043             ("vnode_pager: stale FS putpages\n"));
1044         VM_OBJECT_LOCK(object);
1045 }
1046
1047
1048 /*
1049  * This is now called from local media FS's to operate against their
1050  * own vnodes if they fail to implement VOP_PUTPAGES.
1051  *
1052  * This is typically called indirectly via the pageout daemon and
1053  * clustering has already typically occured, so in general we ask the
1054  * underlying filesystem to write the data out asynchronously rather
1055  * then delayed.
1056  */
1057 int
1058 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals)
1059         struct vnode *vp;
1060         vm_page_t *m;
1061         int bytecount;
1062         int flags;
1063         int *rtvals;
1064 {
1065         int i;
1066         vm_object_t object;
1067         int count;
1068
1069         int maxsize, ncount;
1070         vm_ooffset_t poffset;
1071         struct uio auio;
1072         struct iovec aiov;
1073         int error;
1074         int ioflags;
1075         int ppscheck = 0;
1076         static struct timeval lastfail;
1077         static int curfail;
1078
1079         object = vp->v_object;
1080         count = bytecount / PAGE_SIZE;
1081
1082         for (i = 0; i < count; i++)
1083                 rtvals[i] = VM_PAGER_AGAIN;
1084
1085         if ((int64_t)m[0]->pindex < 0) {
1086                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1087                         (long)m[0]->pindex, (u_long)m[0]->dirty);
1088                 rtvals[0] = VM_PAGER_BAD;
1089                 return VM_PAGER_BAD;
1090         }
1091
1092         maxsize = count * PAGE_SIZE;
1093         ncount = count;
1094
1095         poffset = IDX_TO_OFF(m[0]->pindex);
1096
1097         /*
1098          * If the page-aligned write is larger then the actual file we
1099          * have to invalidate pages occuring beyond the file EOF.  However,
1100          * there is an edge case where a file may not be page-aligned where
1101          * the last page is partially invalid.  In this case the filesystem
1102          * may not properly clear the dirty bits for the entire page (which
1103          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1104          * With the page locked we are free to fix-up the dirty bits here.
1105          *
1106          * We do not under any circumstances truncate the valid bits, as
1107          * this will screw up bogus page replacement.
1108          */
1109         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1110                 if (object->un_pager.vnp.vnp_size > poffset) {
1111                         int pgoff;
1112
1113                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1114                         ncount = btoc(maxsize);
1115                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1116                                 vm_page_lock_queues();
1117                                 vm_page_clear_dirty(m[ncount - 1], pgoff,
1118                                         PAGE_SIZE - pgoff);
1119                                 vm_page_unlock_queues();
1120                         }
1121                 } else {
1122                         maxsize = 0;
1123                         ncount = 0;
1124                 }
1125                 if (ncount < count) {
1126                         for (i = ncount; i < count; i++) {
1127                                 rtvals[i] = VM_PAGER_BAD;
1128                         }
1129                 }
1130         }
1131
1132         /*
1133          * pageouts are already clustered, use IO_ASYNC t o force a bawrite()
1134          * rather then a bdwrite() to prevent paging I/O from saturating
1135          * the buffer cache.  Dummy-up the sequential heuristic to cause
1136          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
1137          * the system decides how to cluster.
1138          */
1139         ioflags = IO_VMIO;
1140         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1141                 ioflags |= IO_SYNC;
1142         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1143                 ioflags |= IO_ASYNC;
1144         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1145         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1146
1147         aiov.iov_base = (caddr_t) 0;
1148         aiov.iov_len = maxsize;
1149         auio.uio_iov = &aiov;
1150         auio.uio_iovcnt = 1;
1151         auio.uio_offset = poffset;
1152         auio.uio_segflg = UIO_NOCOPY;
1153         auio.uio_rw = UIO_WRITE;
1154         auio.uio_resid = maxsize;
1155         auio.uio_td = (struct thread *) 0;
1156         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1157         PCPU_INC(cnt.v_vnodeout);
1158         PCPU_ADD(cnt.v_vnodepgsout, ncount);
1159
1160         if (error) {
1161                 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1162                         printf("vnode_pager_putpages: I/O error %d\n", error);
1163         }
1164         if (auio.uio_resid) {
1165                 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1166                         printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1167                             auio.uio_resid, (u_long)m[0]->pindex);
1168         }
1169         for (i = 0; i < ncount; i++) {
1170                 rtvals[i] = VM_PAGER_OK;
1171         }
1172         return rtvals[0];
1173 }