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 <vm/vm.h>
  69 #include <vm/vm_object.h>
  70 #include <vm/vm_page.h>
  71 #include <vm/vm_pager.h>
  72 #include <vm/vm_map.h>
  73 #include <vm/vnode_pager.h>
  74 #include <vm/vm_extern.h>
  75
  76 static void vnode_pager_init(void);
  77 static daddr_t vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
  78                                          int *run);
  79 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
  80 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
  81 static void vnode_pager_dealloc(vm_object_t);
  82 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int);
  83 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, boolean_t, int *);
  84 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  85 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t);
  86
  87 struct pagerops vnodepagerops = {
  88         .pgo_init =     vnode_pager_init,
  89         .pgo_alloc =    vnode_pager_alloc,
  90         .pgo_dealloc =  vnode_pager_dealloc,
  91         .pgo_getpages = vnode_pager_getpages,
  92         .pgo_putpages = vnode_pager_putpages,
  93         .pgo_haspage =  vnode_pager_haspage,
  94 };
  95
  96 int vnode_pbuf_freecnt;
  97
  98 static void
  99 vnode_pager_init(void)
 100 {
 101
 102         vnode_pbuf_freecnt = nswbuf / 2 + 1;
 103 }
 104
 105 /* Create the VM system backing object for this vnode */
 106 int
 107 vnode_create_vobject(struct vnode *vp, size_t isize, struct thread *td)
 108 {
 109         vm_object_t object;
 110         vm_ooffset_t size = isize;
 111         struct vattr va;
 112
 113         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
 114                 return (0);
 115
 116         while ((object = vp->v_object) != NULL) {
 117                 VM_OBJECT_LOCK(object);
 118                 if (!(object->flags & OBJ_DEAD)) {
 119                         VM_OBJECT_UNLOCK(object);
 120                         return (0);
 121                 }
 122                 VOP_UNLOCK(vp, 0, td);
 123                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 124                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vodead", 0);
 125                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY, td);
 126         }
 127
 128         if (size == 0) {
 129                 if (vn_isdisk(vp, NULL)) {
 130                         size = IDX_TO_OFF(INT_MAX);
 131                 } else {
 132                         if (VOP_GETATTR(vp, &va, td->td_ucred, td) != 0)
 133                                 return (0);
 134                         size = va.va_size;
 135                 }
 136         }
 137
 138         object = vnode_pager_alloc(vp, size, 0, 0);
 139         /*
 140          * Dereference the reference we just created.  This assumes
 141          * that the object is associated with the vp.
 142          */
 143         VM_OBJECT_LOCK(object);
 144         object->ref_count--;
 145         VM_OBJECT_UNLOCK(object);
 146         vrele(vp);
 147
 148         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
 149
 150         return (0);
 151 }
 152
 153 void
 154 vnode_destroy_vobject(struct vnode *vp)
 155 {
 156         struct vm_object *obj;
 157
 158         obj = vp->v_object;
 159         if (obj == NULL)
 160                 return;
 161         ASSERT_VOP_LOCKED(vp, "vnode_destroy_vobject");
 162         VM_OBJECT_LOCK(obj);
 163         if (obj->ref_count == 0) {
 164                 /*
 165                  * vclean() may be called twice. The first time
 166                  * removes the primary reference to the object,
 167                  * the second time goes one further and is a
 168                  * special-case to terminate the object.
 169                  *
 170                  * don't double-terminate the object
 171                  */
 172                 if ((obj->flags & OBJ_DEAD) == 0)
 173                         vm_object_terminate(obj);
 174                 else
 175                         VM_OBJECT_UNLOCK(obj);
 176         } else {
 177                 /*
 178                  * Woe to the process that tries to page now :-).
 179                  */
 180                 vm_pager_deallocate(obj);
 181                 VM_OBJECT_UNLOCK(obj);
 182         }
 183         vp->v_object = NULL;
 184 }
 185
 186
 187 /*
 188  * Allocate (or lookup) pager for a vnode.
 189  * Handle is a vnode pointer.
 190  *
 191  * MPSAFE
 192  */
 193 vm_object_t
 194 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 195                   vm_ooffset_t offset)
 196 {
 197         vm_object_t object;
 198         struct vnode *vp;
 199
 200         /*
 201          * Pageout to vnode, no can do yet.
 202          */
 203         if (handle == NULL)
 204                 return (NULL);
 205
 206         vp = (struct vnode *) handle;
 207
 208         ASSERT_VOP_LOCKED(vp, "vnode_pager_alloc");
 209
 210         /*
 211          * If the object is being terminated, wait for it to
 212          * go away.
 213          */
 214         while ((object = vp->v_object) != NULL) {
 215                 VM_OBJECT_LOCK(object);
 216                 if ((object->flags & OBJ_DEAD) == 0)
 217                         break;
 218                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 219                 msleep(object, VM_OBJECT_MTX(object), PDROP | PVM, "vadead", 0);
 220         }
 221
 222         if (vp->v_usecount == 0)
 223                 panic("vnode_pager_alloc: no vnode reference");
 224
 225         if (object == NULL) {
 226                 /*
 227                  * And an object of the appropriate size
 228                  */
 229                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 230
 231                 object->un_pager.vnp.vnp_size = size;
 232
 233                 object->handle = handle;
 234                 if (VFS_NEEDSGIANT(vp->v_mount))
 235                         vm_object_set_flag(object, OBJ_NEEDGIANT);
 236                 vp->v_object = object;
 237         } else {
 238                 object->ref_count++;
 239                 VM_OBJECT_UNLOCK(object);
 240         }
 241         vref(vp);
 242         return (object);
 243 }
 244
 245 /*
 246  *      The object must be locked.
 247  */
 248 static void
 249 vnode_pager_dealloc(object)
 250         vm_object_t object;
 251 {
 252         struct vnode *vp = object->handle;
 253
 254         if (vp == NULL)
 255                 panic("vnode_pager_dealloc: pager already dealloced");
 256
 257         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 258         vm_object_pip_wait(object, "vnpdea");
 259
 260         object->handle = NULL;
 261         object->type = OBJT_DEAD;
 262         if (object->flags & OBJ_DISCONNECTWNT) {
 263                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 264                 wakeup(object);
 265         }
 266         ASSERT_VOP_LOCKED(vp, "vnode_pager_dealloc");
 267         vp->v_object = NULL;
 268         vp->v_vflag &= ~VV_TEXT;
 269 }
 270
 271 static boolean_t
 272 vnode_pager_haspage(object, pindex, before, after)
 273         vm_object_t object;
 274         vm_pindex_t pindex;
 275         int *before;
 276         int *after;
 277 {
 278         struct vnode *vp = object->handle;
 279         daddr_t bn;
 280         int err;
 281         daddr_t reqblock;
 282         int poff;
 283         int bsize;
 284         int pagesperblock, blocksperpage;
 285         int vfslocked;
 286
 287         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 288         /*
 289          * If no vp or vp is doomed or marked transparent to VM, we do not
 290          * have the page.
 291          */
 292         if (vp == NULL)
 293                 return FALSE;
 294
 295         VI_LOCK(vp);
 296         if (vp->v_iflag & VI_DOOMED) {
 297                 VI_UNLOCK(vp);
 298                 return FALSE;
 299         }
 300         VI_UNLOCK(vp);
 301         /*
 302          * If filesystem no longer mounted or offset beyond end of file we do
 303          * not have the page.
 304          */
 305         if ((vp->v_mount == NULL) ||
 306             (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size))
 307                 return FALSE;
 308
 309         bsize = vp->v_mount->mnt_stat.f_iosize;
 310         pagesperblock = bsize / PAGE_SIZE;
 311         blocksperpage = 0;
 312         if (pagesperblock > 0) {
 313                 reqblock = pindex / pagesperblock;
 314         } else {
 315                 blocksperpage = (PAGE_SIZE / bsize);
 316                 reqblock = pindex * blocksperpage;
 317         }
 318         VM_OBJECT_UNLOCK(object);
 319         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 320         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 321         VFS_UNLOCK_GIANT(vfslocked);
 322         VM_OBJECT_LOCK(object);
 323         if (err)
 324                 return TRUE;
 325         if (bn == -1)
 326                 return FALSE;
 327         if (pagesperblock > 0) {
 328                 poff = pindex - (reqblock * pagesperblock);
 329                 if (before) {
 330                         *before *= pagesperblock;
 331                         *before += poff;
 332                 }
 333                 if (after) {
 334                         int numafter;
 335                         *after *= pagesperblock;
 336                         numafter = pagesperblock - (poff + 1);
 337                         if (IDX_TO_OFF(pindex + numafter) >
 338                             object->un_pager.vnp.vnp_size) {
 339                                 numafter =
 340                                     OFF_TO_IDX(object->un_pager.vnp.vnp_size) -
 341                                     pindex;
 342                         }
 343                         *after += numafter;
 344                 }
 345         } else {
 346                 if (before) {
 347                         *before /= blocksperpage;
 348                 }
 349
 350                 if (after) {
 351                         *after /= blocksperpage;
 352                 }
 353         }
 354         return TRUE;
 355 }
 356
 357 /*
 358  * Lets the VM system know about a change in size for a file.
 359  * We adjust our own internal size and flush any cached pages in
 360  * the associated object that are affected by the size change.
 361  *
 362  * Note: this routine may be invoked as a result of a pager put
 363  * operation (possibly at object termination time), so we must be careful.
 364  */
 365 void
 366 vnode_pager_setsize(vp, nsize)
 367         struct vnode *vp;
 368         vm_ooffset_t nsize;
 369 {
 370         vm_object_t object;
 371         vm_page_t m;
 372         vm_pindex_t nobjsize;
 373
 374         if ((object = vp->v_object) == NULL)
 375                 return;
 376         VM_OBJECT_LOCK(object);
 377         if (nsize == object->un_pager.vnp.vnp_size) {
 378                 /*
 379                  * Hasn't changed size
 380                  */
 381                 VM_OBJECT_UNLOCK(object);
 382                 return;
 383         }
 384         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 385         if (nsize < object->un_pager.vnp.vnp_size) {
 386                 /*
 387                  * File has shrunk. Toss any cached pages beyond the new EOF.
 388                  */
 389                 if (nobjsize < object->size)
 390                         vm_object_page_remove(object, nobjsize, object->size,
 391                             FALSE);
 392                 /*
 393                  * this gets rid of garbage at the end of a page that is now
 394                  * only partially backed by the vnode.
 395                  *
 396                  * XXX for some reason (I don't know yet), if we take a
 397                  * completely invalid page and mark it partially valid
 398                  * it can screw up NFS reads, so we don't allow the case.
 399                  */
 400                 if ((nsize & PAGE_MASK) &&
 401                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 402                     m->valid != 0) {
 403                         int base = (int)nsize & PAGE_MASK;
 404                         int size = PAGE_SIZE - base;
 405
 406                         /*
 407                          * Clear out partial-page garbage in case
 408                          * the page has been mapped.
 409                          */
 410                         pmap_zero_page_area(m, base, size);
 411
 412                         /*
 413                          * XXX work around SMP data integrity race
 414                          * by unmapping the page from user processes.
 415                          * The garbage we just cleared may be mapped
 416                          * to a user process running on another cpu
 417                          * and this code is not running through normal
 418                          * I/O channels which handle SMP issues for
 419                          * us, so unmap page to synchronize all cpus.
 420                          *
 421                          * XXX should vm_pager_unmap_page() have
 422                          * dealt with this?
 423                          */
 424                         vm_page_lock_queues();
 425                         pmap_remove_all(m);
 426
 427                         /*
 428                          * Clear out partial-page dirty bits.  This
 429                          * has the side effect of setting the valid
 430                          * bits, but that is ok.  There are a bunch
 431                          * of places in the VM system where we expected
 432                          * m->dirty == VM_PAGE_BITS_ALL.  The file EOF
 433                          * case is one of them.  If the page is still
 434                          * partially dirty, make it fully dirty.
 435                          *
 436                          * note that we do not clear out the valid
 437                          * bits.  This would prevent bogus_page
 438                          * replacement from working properly.
 439                          */
 440                         vm_page_set_validclean(m, base, size);
 441                         if (m->dirty != 0)
 442                                 m->dirty = VM_PAGE_BITS_ALL;
 443                         vm_page_unlock_queues();
 444                 }
 445         }
 446         object->un_pager.vnp.vnp_size = nsize;
 447         object->size = nobjsize;
 448         VM_OBJECT_UNLOCK(object);
 449 }
 450
 451 /*
 452  * calculate the linear (byte) disk address of specified virtual
 453  * file address
 454  */
 455 static daddr_t
 456 vnode_pager_addr(vp, address, run)
 457         struct vnode *vp;
 458         vm_ooffset_t address;
 459         int *run;
 460 {
 461         daddr_t rtaddress;
 462         int bsize;
 463         daddr_t block;
 464         int err;
 465         daddr_t vblock;
 466         daddr_t voffset;
 467
 468         if (address < 0)
 469                 return -1;
 470
 471         if (vp->v_mount == NULL)
 472                 return -1;
 473
 474         bsize = vp->v_mount->mnt_stat.f_iosize;
 475         vblock = address / bsize;
 476         voffset = address % bsize;
 477
 478         err = VOP_BMAP(vp, vblock, NULL, &block, run, NULL);
 479
 480         if (err || (block == -1))
 481                 rtaddress = -1;
 482         else {
 483                 rtaddress = block + voffset / DEV_BSIZE;
 484                 if (run) {
 485                         *run += 1;
 486                         *run *= bsize/PAGE_SIZE;
 487                         *run -= voffset/PAGE_SIZE;
 488                 }
 489         }
 490
 491         return rtaddress;
 492 }
 493
 494 /*
 495  * small block filesystem vnode pager input
 496  */
 497 static int
 498 vnode_pager_input_smlfs(object, m)
 499         vm_object_t object;
 500         vm_page_t m;
 501 {
 502         int i;
 503         struct vnode *vp;
 504         struct bufobj *bo;
 505         struct buf *bp;
 506         struct sf_buf *sf;
 507         daddr_t fileaddr;
 508         vm_offset_t bsize;
 509         int error = 0;
 510
 511         vp = object->handle;
 512         if (vp->v_mount == NULL)
 513                 return VM_PAGER_BAD;
 514
 515         bsize = vp->v_mount->mnt_stat.f_iosize;
 516
 517         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 518
 519         sf = sf_buf_alloc(m, 0);
 520
 521         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 522                 vm_ooffset_t address;
 523
 524                 if (vm_page_bits(i * bsize, bsize) & m->valid)
 525                         continue;
 526
 527                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 528                 if (address >= object->un_pager.vnp.vnp_size) {
 529                         fileaddr = -1;
 530                 } else {
 531                         fileaddr = vnode_pager_addr(vp, address, NULL);
 532                 }
 533                 if (fileaddr != -1) {
 534                         bp = getpbuf(&vnode_pbuf_freecnt);
 535
 536                         /* build a minimal buffer header */
 537                         bp->b_iocmd = BIO_READ;
 538                         bp->b_iodone = bdone;
 539                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 540                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 541                         bp->b_rcred = crhold(curthread->td_ucred);
 542                         bp->b_wcred = crhold(curthread->td_ucred);
 543                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 544                         bp->b_blkno = fileaddr;
 545                         pbgetbo(bo, bp);
 546                         bp->b_bcount = bsize;
 547                         bp->b_bufsize = bsize;
 548                         bp->b_runningbufspace = bp->b_bufsize;
 549                         runningbufspace += bp->b_runningbufspace;
 550
 551                         /* do the input */
 552                         bp->b_iooffset = dbtob(bp->b_blkno);
 553                         bstrategy(bp);
 554
 555                         bwait(bp, PVM, "vnsrd");
 556
 557                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 558                                 error = EIO;
 559
 560                         /*
 561                          * free the buffer header back to the swap buffer pool
 562                          */
 563                         pbrelbo(bp);
 564                         relpbuf(bp, &vnode_pbuf_freecnt);
 565                         if (error)
 566                                 break;
 567
 568                         VM_OBJECT_LOCK(object);
 569                         vm_page_lock_queues();
 570                         vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize);
 571                         vm_page_unlock_queues();
 572                         VM_OBJECT_UNLOCK(object);
 573                 } else {
 574                         VM_OBJECT_LOCK(object);
 575                         vm_page_lock_queues();
 576                         vm_page_set_validclean(m, (i * bsize) & PAGE_MASK, bsize);
 577                         vm_page_unlock_queues();
 578                         VM_OBJECT_UNLOCK(object);
 579                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 580                 }
 581         }
 582         sf_buf_free(sf);
 583         vm_page_lock_queues();
 584         pmap_clear_modify(m);
 585         vm_page_unlock_queues();
 586         if (error) {
 587                 return VM_PAGER_ERROR;
 588         }
 589         return VM_PAGER_OK;
 590
 591 }
 592
 593
 594 /*
 595  * old style vnode pager input routine
 596  */
 597 static int
 598 vnode_pager_input_old(object, m)
 599         vm_object_t object;
 600         vm_page_t m;
 601 {
 602         struct uio auio;
 603         struct iovec aiov;
 604         int error;
 605         int size;
 606         struct sf_buf *sf;
 607         struct vnode *vp;
 608
 609         VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
 610         error = 0;
 611
 612         /*
 613          * Return failure if beyond current EOF
 614          */
 615         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 616                 return VM_PAGER_BAD;
 617         } else {
 618                 size = PAGE_SIZE;
 619                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 620                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 621                 vp = object->handle;
 622                 VM_OBJECT_UNLOCK(object);
 623
 624                 /*
 625                  * Allocate a kernel virtual address and initialize so that
 626                  * we can use VOP_READ/WRITE routines.
 627                  */
 628                 sf = sf_buf_alloc(m, 0);
 629
 630                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 631                 aiov.iov_len = size;
 632                 auio.uio_iov = &aiov;
 633                 auio.uio_iovcnt = 1;
 634                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 635                 auio.uio_segflg = UIO_SYSSPACE;
 636                 auio.uio_rw = UIO_READ;
 637                 auio.uio_resid = size;
 638                 auio.uio_td = curthread;
 639
 640                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 641                 if (!error) {
 642                         int count = size - auio.uio_resid;
 643
 644                         if (count == 0)
 645                                 error = EINVAL;
 646                         else if (count != PAGE_SIZE)
 647                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 648                                     PAGE_SIZE - count);
 649                 }
 650                 sf_buf_free(sf);
 651
 652                 VM_OBJECT_LOCK(object);
 653         }
 654         vm_page_lock_queues();
 655         pmap_clear_modify(m);
 656         vm_page_undirty(m);
 657         vm_page_unlock_queues();
 658         if (!error)
 659                 m->valid = VM_PAGE_BITS_ALL;
 660         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 661 }
 662
 663 /*
 664  * generic vnode pager input routine
 665  */
 666
 667 /*
 668  * Local media VFS's that do not implement their own VOP_GETPAGES
 669  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 670  * to implement the previous behaviour.
 671  *
 672  * All other FS's should use the bypass to get to the local media
 673  * backing vp's VOP_GETPAGES.
 674  */
 675 static int
 676 vnode_pager_getpages(object, m, count, reqpage)
 677         vm_object_t object;
 678         vm_page_t *m;
 679         int count;
 680         int reqpage;
 681 {
 682         int rtval;
 683         struct vnode *vp;
 684         int bytes = count * PAGE_SIZE;
 685         int vfslocked;
 686
 687         vp = object->handle;
 688         VM_OBJECT_UNLOCK(object);
 689         vfslocked = VFS_LOCK_GIANT(vp->v_mount);
 690         rtval = VOP_GETPAGES(vp, m, bytes, reqpage, 0);
 691         KASSERT(rtval != EOPNOTSUPP,
 692             ("vnode_pager: FS getpages not implemented\n"));
 693         VFS_UNLOCK_GIANT(vfslocked);
 694         VM_OBJECT_LOCK(object);
 695         return rtval;
 696 }
 697
 698 /*
 699  * This is now called from local media FS's to operate against their
 700  * own vnodes if they fail to implement VOP_GETPAGES.
 701  */
 702 int
 703 vnode_pager_generic_getpages(vp, m, bytecount, reqpage)
 704         struct vnode *vp;
 705         vm_page_t *m;
 706         int bytecount;
 707         int reqpage;
 708 {
 709         vm_object_t object;
 710         vm_offset_t kva;
 711         off_t foff, tfoff, nextoff;
 712         int i, j, size, bsize, first;
 713         daddr_t firstaddr;
 714         struct bufobj *bo;
 715         int runpg;
 716         int runend;
 717         struct buf *bp;
 718         int count;
 719         int error = 0;
 720
 721         object = vp->v_object;
 722         count = bytecount / PAGE_SIZE;
 723
 724         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 725             ("vnode_pager_generic_getpages does not support devices"));
 726         if (vp->v_mount == NULL)
 727                 return VM_PAGER_BAD;
 728
 729         bsize = vp->v_mount->mnt_stat.f_iosize;
 730
 731         /* get the UNDERLYING device for the file with VOP_BMAP() */
 732
 733         /*
 734          * originally, we did not check for an error return value -- assuming
 735          * an fs always has a bmap entry point -- that assumption is wrong!!!
 736          */
 737         foff = IDX_TO_OFF(m[reqpage]->pindex);
 738
 739         /*
 740          * if we can't bmap, use old VOP code
 741          */
 742         if (VOP_BMAP(vp, 0, &bo, 0, NULL, NULL)) {
 743                 VM_OBJECT_LOCK(object);
 744                 vm_page_lock_queues();
 745                 for (i = 0; i < count; i++)
 746                         if (i != reqpage)
 747                                 vm_page_free(m[i]);
 748                 vm_page_unlock_queues();
 749                 cnt.v_vnodein++;
 750                 cnt.v_vnodepgsin++;
 751                 error = vnode_pager_input_old(object, m[reqpage]);
 752                 VM_OBJECT_UNLOCK(object);
 753                 return (error);
 754
 755                 /*
 756                  * if the blocksize is smaller than a page size, then use
 757                  * special small filesystem code.  NFS sometimes has a small
 758                  * blocksize, but it can handle large reads itself.
 759                  */
 760         } else if ((PAGE_SIZE / bsize) > 1 &&
 761             (vp->v_mount->mnt_stat.f_type != nfs_mount_type)) {
 762                 VM_OBJECT_LOCK(object);
 763                 vm_page_lock_queues();
 764                 for (i = 0; i < count; i++)
 765                         if (i != reqpage)
 766                                 vm_page_free(m[i]);
 767                 vm_page_unlock_queues();
 768                 VM_OBJECT_UNLOCK(object);
 769                 cnt.v_vnodein++;
 770                 cnt.v_vnodepgsin++;
 771                 return vnode_pager_input_smlfs(object, m[reqpage]);
 772         }
 773
 774         /*
 775          * If we have a completely valid page available to us, we can
 776          * clean up and return.  Otherwise we have to re-read the
 777          * media.
 778          */
 779         VM_OBJECT_LOCK(object);
 780         if (m[reqpage]->valid == VM_PAGE_BITS_ALL) {
 781                 vm_page_lock_queues();
 782                 for (i = 0; i < count; i++)
 783                         if (i != reqpage)
 784                                 vm_page_free(m[i]);
 785                 vm_page_unlock_queues();
 786                 VM_OBJECT_UNLOCK(object);
 787                 return VM_PAGER_OK;
 788         }
 789         m[reqpage]->valid = 0;
 790         VM_OBJECT_UNLOCK(object);
 791
 792         /*
 793          * here on direct device I/O
 794          */
 795         firstaddr = -1;
 796
 797         /*
 798          * calculate the run that includes the required page
 799          */
 800         for (first = 0, i = 0; i < count; i = runend) {
 801                 firstaddr = vnode_pager_addr(vp,
 802                         IDX_TO_OFF(m[i]->pindex), &runpg);
 803                 if (firstaddr == -1) {
 804                         VM_OBJECT_LOCK(object);
 805                         if (i == reqpage && foff < object->un_pager.vnp.vnp_size) {
 806                                 panic("vnode_pager_getpages: unexpected missing page: firstaddr: %jd, foff: 0x%jx%08jx, vnp_size: 0x%jx%08jx",
 807                                     (intmax_t)firstaddr, (uintmax_t)(foff >> 32),
 808                                     (uintmax_t)foff,
 809                                     (uintmax_t)
 810                                     (object->un_pager.vnp.vnp_size >> 32),
 811                                     (uintmax_t)object->un_pager.vnp.vnp_size);
 812                         }
 813                         vm_page_lock_queues();
 814                         vm_page_free(m[i]);
 815                         vm_page_unlock_queues();
 816                         VM_OBJECT_UNLOCK(object);
 817                         runend = i + 1;
 818                         first = runend;
 819                         continue;
 820                 }
 821                 runend = i + runpg;
 822                 if (runend <= reqpage) {
 823                         VM_OBJECT_LOCK(object);
 824                         vm_page_lock_queues();
 825                         for (j = i; j < runend; j++)
 826                                 vm_page_free(m[j]);
 827                         vm_page_unlock_queues();
 828                         VM_OBJECT_UNLOCK(object);
 829                 } else {
 830                         if (runpg < (count - first)) {
 831                                 VM_OBJECT_LOCK(object);
 832                                 vm_page_lock_queues();
 833                                 for (i = first + runpg; i < count; i++)
 834                                         vm_page_free(m[i]);
 835                                 vm_page_unlock_queues();
 836                                 VM_OBJECT_UNLOCK(object);
 837                                 count = first + runpg;
 838                         }
 839                         break;
 840                 }
 841                 first = runend;
 842         }
 843
 844         /*
 845          * the first and last page have been calculated now, move input pages
 846          * to be zero based...
 847          */
 848         if (first != 0) {
 849                 for (i = first; i < count; i++) {
 850                         m[i - first] = m[i];
 851                 }
 852                 count -= first;
 853                 reqpage -= first;
 854         }
 855
 856         /*
 857          * calculate the file virtual address for the transfer
 858          */
 859         foff = IDX_TO_OFF(m[0]->pindex);
 860
 861         /*
 862          * calculate the size of the transfer
 863          */
 864         size = count * PAGE_SIZE;
 865         KASSERT(count > 0, ("zero count"));
 866         if ((foff + size) > object->un_pager.vnp.vnp_size)
 867                 size = object->un_pager.vnp.vnp_size - foff;
 868         KASSERT(size > 0, ("zero size"));
 869
 870         /*
 871          * round up physical size for real devices.
 872          */
 873         if (1) {
 874                 int secmask = bo->bo_bsize - 1;
 875                 KASSERT(secmask < PAGE_SIZE && secmask > 0,
 876                     ("vnode_pager_generic_getpages: sector size %d too large",
 877                     secmask + 1));
 878                 size = (size + secmask) & ~secmask;
 879         }
 880
 881         bp = getpbuf(&vnode_pbuf_freecnt);
 882         kva = (vm_offset_t) bp->b_data;
 883
 884         /*
 885          * and map the pages to be read into the kva
 886          */
 887         pmap_qenter(kva, m, count);
 888
 889         /* build a minimal buffer header */
 890         bp->b_iocmd = BIO_READ;
 891         bp->b_iodone = bdone;
 892         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 893         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 894         bp->b_rcred = crhold(curthread->td_ucred);
 895         bp->b_wcred = crhold(curthread->td_ucred);
 896         bp->b_blkno = firstaddr;
 897         pbgetbo(bo, bp);
 898         bp->b_bcount = size;
 899         bp->b_bufsize = size;
 900         bp->b_runningbufspace = bp->b_bufsize;
 901         runningbufspace += bp->b_runningbufspace;
 902
 903         cnt.v_vnodein++;
 904         cnt.v_vnodepgsin += count;
 905
 906         /* do the input */
 907         bp->b_iooffset = dbtob(bp->b_blkno);
 908         bstrategy(bp);
 909
 910         bwait(bp, PVM, "vnread");
 911
 912         if ((bp->b_ioflags & BIO_ERROR) != 0)
 913                 error = EIO;
 914
 915         if (!error) {
 916                 if (size != count * PAGE_SIZE)
 917                         bzero((caddr_t) kva + size, PAGE_SIZE * count - size);
 918         }
 919         pmap_qremove(kva, count);
 920
 921         /*
 922          * free the buffer header back to the swap buffer pool
 923          */
 924         pbrelbo(bp);
 925         relpbuf(bp, &vnode_pbuf_freecnt);
 926
 927         VM_OBJECT_LOCK(object);
 928         vm_page_lock_queues();
 929         for (i = 0, tfoff = foff; i < count; i++, tfoff = nextoff) {
 930                 vm_page_t mt;
 931
 932                 nextoff = tfoff + PAGE_SIZE;
 933                 mt = m[i];
 934
 935                 if (nextoff <= object->un_pager.vnp.vnp_size) {
 936                         /*
 937                          * Read filled up entire page.
 938                          */
 939                         mt->valid = VM_PAGE_BITS_ALL;
 940                         vm_page_undirty(mt);    /* should be an assert? XXX */
 941                         pmap_clear_modify(mt);
 942                 } else {
 943                         /*
 944                          * Read did not fill up entire page.  Since this
 945                          * is getpages, the page may be mapped, so we have
 946                          * to zero the invalid portions of the page even
 947                          * though we aren't setting them valid.
 948                          *
 949                          * Currently we do not set the entire page valid,
 950                          * we just try to clear the piece that we couldn't
 951                          * read.
 952                          */
 953                         vm_page_set_validclean(mt, 0,
 954                             object->un_pager.vnp.vnp_size - tfoff);
 955                         /* handled by vm_fault now */
 956                         /* vm_page_zero_invalid(mt, FALSE); */
 957                 }
 958
 959                 if (i != reqpage) {
 960
 961                         /*
 962                          * whether or not to leave the page activated is up in
 963                          * the air, but we should put the page on a page queue
 964                          * somewhere. (it already is in the object). Result:
 965                          * It appears that empirical results show that
 966                          * deactivating pages is best.
 967                          */
 968
 969                         /*
 970                          * just in case someone was asking for this page we
 971                          * now tell them that it is ok to use
 972                          */
 973                         if (!error) {
 974                                 if (mt->flags & PG_WANTED)
 975                                         vm_page_activate(mt);
 976                                 else
 977                                         vm_page_deactivate(mt);
 978                                 vm_page_wakeup(mt);
 979                         } else {
 980                                 vm_page_free(mt);
 981                         }
 982                 }
 983         }
 984         vm_page_unlock_queues();
 985         VM_OBJECT_UNLOCK(object);
 986         if (error) {
 987                 printf("vnode_pager_getpages: I/O read error\n");
 988         }
 989         return (error ? VM_PAGER_ERROR : VM_PAGER_OK);
 990 }
 991
 992 /*
 993  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
 994  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
 995  * vnode_pager_generic_putpages() to implement the previous behaviour.
 996  *
 997  * All other FS's should use the bypass to get to the local media
 998  * backing vp's VOP_PUTPAGES.
 999  */
1000 static void
1001 vnode_pager_putpages(object, m, count, sync, rtvals)
1002         vm_object_t object;
1003         vm_page_t *m;
1004         int count;
1005         boolean_t sync;
1006         int *rtvals;
1007 {
1008         int rtval;
1009         struct vnode *vp;
1010         struct mount *mp;
1011         int bytes = count * PAGE_SIZE;
1012
1013         /*
1014          * Force synchronous operation if we are extremely low on memory
1015          * to prevent a low-memory deadlock.  VOP operations often need to
1016          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1017          * operation ).  The swapper handles the case by limiting the amount
1018          * of asynchronous I/O, but that sort of solution doesn't scale well
1019          * for the vnode pager without a lot of work.
1020          *
1021          * Also, the backing vnode's iodone routine may not wake the pageout
1022          * daemon up.  This should be probably be addressed XXX.
1023          */
1024
1025         if ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)
1026                 sync |= OBJPC_SYNC;
1027
1028         /*
1029          * Call device-specific putpages function
1030          */
1031         vp = object->handle;
1032         VM_OBJECT_UNLOCK(object);
1033         if (vp->v_type != VREG)
1034                 mp = NULL;
1035         (void)vn_start_write(vp, &mp, V_WAIT);
1036         rtval = VOP_PUTPAGES(vp, m, bytes, sync, rtvals, 0);
1037         KASSERT(rtval != EOPNOTSUPP,
1038             ("vnode_pager: stale FS putpages\n"));
1039         vn_finished_write(mp);
1040         VM_OBJECT_LOCK(object);
1041 }
1042
1043
1044 /*
1045  * This is now called from local media FS's to operate against their
1046  * own vnodes if they fail to implement VOP_PUTPAGES.
1047  *
1048  * This is typically called indirectly via the pageout daemon and
1049  * clustering has already typically occured, so in general we ask the
1050  * underlying filesystem to write the data out asynchronously rather
1051  * then delayed.
1052  */
1053 int
1054 vnode_pager_generic_putpages(vp, m, bytecount, flags, rtvals)
1055         struct vnode *vp;
1056         vm_page_t *m;
1057         int bytecount;
1058         int flags;
1059         int *rtvals;
1060 {
1061         int i;
1062         vm_object_t object;
1063         int count;
1064
1065         int maxsize, ncount;
1066         vm_ooffset_t poffset;
1067         struct uio auio;
1068         struct iovec aiov;
1069         int error;
1070         int ioflags;
1071
1072         object = vp->v_object;
1073         count = bytecount / PAGE_SIZE;
1074
1075         for (i = 0; i < count; i++)
1076                 rtvals[i] = VM_PAGER_AGAIN;
1077
1078         if ((int64_t)m[0]->pindex < 0) {
1079                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1080                         (long)m[0]->pindex, (u_long)m[0]->dirty);
1081                 rtvals[0] = VM_PAGER_BAD;
1082                 return VM_PAGER_BAD;
1083         }
1084
1085         maxsize = count * PAGE_SIZE;
1086         ncount = count;
1087
1088         poffset = IDX_TO_OFF(m[0]->pindex);
1089
1090         /*
1091          * If the page-aligned write is larger then the actual file we
1092          * have to invalidate pages occuring beyond the file EOF.  However,
1093          * there is an edge case where a file may not be page-aligned where
1094          * the last page is partially invalid.  In this case the filesystem
1095          * may not properly clear the dirty bits for the entire page (which
1096          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1097          * With the page locked we are free to fix-up the dirty bits here.
1098          *
1099          * We do not under any circumstances truncate the valid bits, as
1100          * this will screw up bogus page replacement.
1101          */
1102         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1103                 if (object->un_pager.vnp.vnp_size > poffset) {
1104                         int pgoff;
1105
1106                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1107                         ncount = btoc(maxsize);
1108                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1109                                 vm_page_lock_queues();
1110                                 vm_page_clear_dirty(m[ncount - 1], pgoff,
1111                                         PAGE_SIZE - pgoff);
1112                                 vm_page_unlock_queues();
1113                         }
1114                 } else {
1115                         maxsize = 0;
1116                         ncount = 0;
1117                 }
1118                 if (ncount < count) {
1119                         for (i = ncount; i < count; i++) {
1120                                 rtvals[i] = VM_PAGER_BAD;
1121                         }
1122                 }
1123         }
1124
1125         /*
1126          * pageouts are already clustered, use IO_ASYNC t o force a bawrite()
1127          * rather then a bdwrite() to prevent paging I/O from saturating
1128          * the buffer cache.  Dummy-up the sequential heuristic to cause
1129          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
1130          * the system decides how to cluster.
1131          */
1132         ioflags = IO_VMIO;
1133         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1134                 ioflags |= IO_SYNC;
1135         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1136                 ioflags |= IO_ASYNC;
1137         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1138         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1139
1140         aiov.iov_base = (caddr_t) 0;
1141         aiov.iov_len = maxsize;
1142         auio.uio_iov = &aiov;
1143         auio.uio_iovcnt = 1;
1144         auio.uio_offset = poffset;
1145         auio.uio_segflg = UIO_NOCOPY;
1146         auio.uio_rw = UIO_WRITE;
1147         auio.uio_resid = maxsize;
1148         auio.uio_td = (struct thread *) 0;
1149         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1150         cnt.v_vnodeout++;
1151         cnt.v_vnodepgsout += ncount;
1152
1153         if (error) {
1154                 printf("vnode_pager_putpages: I/O error %d\n", error);
1155         }
1156         if (auio.uio_resid) {
1157                 printf("vnode_pager_putpages: residual I/O %d at %lu\n",
1158                     auio.uio_resid, (u_long)m[0]->pindex);
1159         }
1160         for (i = 0; i < ncount; i++) {
1161                 rtvals[i] = VM_PAGER_OK;
1162         }
1163         return rtvals[0];
1164 }
1165
1166 struct vnode *
1167 vnode_pager_lock(vm_object_t first_object)
1168 {
1169         struct vnode *vp;
1170         vm_object_t backing_object, object;
1171
1172         VM_OBJECT_LOCK_ASSERT(first_object, MA_OWNED);
1173         for (object = first_object; object != NULL; object = backing_object) {
1174                 if (object->type != OBJT_VNODE) {
1175                         if ((backing_object = object->backing_object) != NULL)
1176                                 VM_OBJECT_LOCK(backing_object);
1177                         if (object != first_object)
1178                                 VM_OBJECT_UNLOCK(object);
1179                         continue;
1180                 }
1181         retry:
1182                 if (object->flags & OBJ_DEAD) {
1183                         if (object != first_object)
1184                                 VM_OBJECT_UNLOCK(object);
1185                         return NULL;
1186                 }
1187                 vp = object->handle;
1188                 VI_LOCK(vp);
1189                 VM_OBJECT_UNLOCK(object);
1190                 if (first_object != object)
1191                         VM_OBJECT_UNLOCK(first_object);
1192                 VFS_ASSERT_GIANT(vp->v_mount);
1193                 if (vget(vp, LK_CANRECURSE | LK_INTERLOCK |
1194                     LK_RETRY | LK_SHARED, curthread)) {
1195                         VM_OBJECT_LOCK(first_object);
1196                         if (object != first_object)
1197                                 VM_OBJECT_LOCK(object);
1198                         if (object->type != OBJT_VNODE) {
1199                                 if (object != first_object)
1200                                         VM_OBJECT_UNLOCK(object);
1201                                 return NULL;
1202                         }
1203                         printf("vnode_pager_lock: retrying\n");
1204                         goto retry;
1205                 }
1206                 VM_OBJECT_LOCK(first_object);
1207                 return (vp);
1208         }
1209         return NULL;
1210 }