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 "opt_vm.h"
  57
  58 #include <sys/param.h>
  59 #include <sys/systm.h>
  60 #include <sys/proc.h>
  61 #include <sys/vnode.h>
  62 #include <sys/mount.h>
  63 #include <sys/bio.h>
  64 #include <sys/buf.h>
  65 #include <sys/vmmeter.h>
  66 #include <sys/limits.h>
  67 #include <sys/conf.h>
  68 #include <sys/rwlock.h>
  69 #include <sys/sf_buf.h>
  70
  71 #include <machine/atomic.h>
  72
  73 #include <vm/vm.h>
  74 #include <vm/vm_param.h>
  75 #include <vm/vm_object.h>
  76 #include <vm/vm_page.h>
  77 #include <vm/vm_pager.h>
  78 #include <vm/vm_map.h>
  79 #include <vm/vnode_pager.h>
  80 #include <vm/vm_extern.h>
  81
  82 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
  83     daddr_t *rtaddress, int *run);
  84 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
  85 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
  86 static void vnode_pager_dealloc(vm_object_t);
  87 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
  88 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *,
  89     int *, vop_getpages_iodone_t, void *);
  90 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
  91 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  92 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  93     vm_ooffset_t, struct ucred *cred);
  94 static int vnode_pager_generic_getpages_done(struct buf *);
  95 static void vnode_pager_generic_getpages_done_async(struct buf *);
  96
  97 struct pagerops vnodepagerops = {
  98         .pgo_alloc =    vnode_pager_alloc,
  99         .pgo_dealloc =  vnode_pager_dealloc,
 100         .pgo_getpages = vnode_pager_getpages,
 101         .pgo_getpages_async = vnode_pager_getpages_async,
 102         .pgo_putpages = vnode_pager_putpages,
 103         .pgo_haspage =  vnode_pager_haspage,
 104 };
 105
 106 int vnode_pbuf_freecnt;
 107 int vnode_async_pbuf_freecnt;
 108
 109 /* Create the VM system backing object for this vnode */
 110 int
 111 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
 112 {
 113         vm_object_t object;
 114         vm_ooffset_t size = isize;
 115         struct vattr va;
 116
 117         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
 118                 return (0);
 119
 120         while ((object = vp->v_object) != NULL) {
 121                 VM_OBJECT_WLOCK(object);
 122                 if (!(object->flags & OBJ_DEAD)) {
 123                         VM_OBJECT_WUNLOCK(object);
 124                         return (0);
 125                 }
 126                 VOP_UNLOCK(vp, 0);
 127                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 128                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0);
 129                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 130         }
 131
 132         if (size == 0) {
 133                 if (vn_isdisk(vp, NULL)) {
 134                         size = IDX_TO_OFF(INT_MAX);
 135                 } else {
 136                         if (VOP_GETATTR(vp, &va, td->td_ucred))
 137                                 return (0);
 138                         size = va.va_size;
 139                 }
 140         }
 141
 142         object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
 143         /*
 144          * Dereference the reference we just created.  This assumes
 145          * that the object is associated with the vp.
 146          */
 147         VM_OBJECT_WLOCK(object);
 148         object->ref_count--;
 149         VM_OBJECT_WUNLOCK(object);
 150         vrele(vp);
 151
 152         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
 153
 154         return (0);
 155 }
 156
 157 void
 158 vnode_destroy_vobject(struct vnode *vp)
 159 {
 160         struct vm_object *obj;
 161
 162         obj = vp->v_object;
 163         if (obj == NULL)
 164                 return;
 165         ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
 166         VM_OBJECT_WLOCK(obj);
 167         if (obj->ref_count == 0) {
 168                 /*
 169                  * don't double-terminate the object
 170                  */
 171                 if ((obj->flags & OBJ_DEAD) == 0)
 172                         vm_object_terminate(obj);
 173                 else
 174                         VM_OBJECT_WUNLOCK(obj);
 175         } else {
 176                 /*
 177                  * Woe to the process that tries to page now :-).
 178                  */
 179                 vm_pager_deallocate(obj);
 180                 VM_OBJECT_WUNLOCK(obj);
 181         }
 182         vp->v_object = NULL;
 183 }
 184
 185
 186 /*
 187  * Allocate (or lookup) pager for a vnode.
 188  * Handle is a vnode pointer.
 189  *
 190  * MPSAFE
 191  */
 192 vm_object_t
 193 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 194     vm_ooffset_t offset, struct ucred *cred)
 195 {
 196         vm_object_t object;
 197         struct vnode *vp;
 198
 199         /*
 200          * Pageout to vnode, no can do yet.
 201          */
 202         if (handle == NULL)
 203                 return (NULL);
 204
 205         vp = (struct vnode *) handle;
 206
 207         /*
 208          * If the object is being terminated, wait for it to
 209          * go away.
 210          */
 211 retry:
 212         while ((object = vp->v_object) != NULL) {
 213                 VM_OBJECT_WLOCK(object);
 214                 if ((object->flags & OBJ_DEAD) == 0)
 215                         break;
 216                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 217                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
 218         }
 219
 220         KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
 221
 222         if (object == NULL) {
 223                 /*
 224                  * Add an object of the appropriate size
 225                  */
 226                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 227
 228                 object->un_pager.vnp.vnp_size = size;
 229                 object->un_pager.vnp.writemappings = 0;
 230
 231                 object->handle = handle;
 232                 VI_LOCK(vp);
 233                 if (vp->v_object != NULL) {
 234                         /*
 235                          * Object has been created while we were sleeping
 236                          */
 237                         VI_UNLOCK(vp);
 238                         VM_OBJECT_WLOCK(object);
 239                         KASSERT(object->ref_count == 1,
 240                             ("leaked ref %p %d", object, object->ref_count));
 241                         object->type = OBJT_DEAD;
 242                         object->ref_count = 0;
 243                         VM_OBJECT_WUNLOCK(object);
 244                         vm_object_destroy(object);
 245                         goto retry;
 246                 }
 247                 vp->v_object = object;
 248                 VI_UNLOCK(vp);
 249         } else {
 250                 object->ref_count++;
 251 #if VM_NRESERVLEVEL > 0
 252                 vm_object_color(object, 0);
 253 #endif
 254                 VM_OBJECT_WUNLOCK(object);
 255         }
 256         vref(vp);
 257         return (object);
 258 }
 259
 260 /*
 261  *      The object must be locked.
 262  */
 263 static void
 264 vnode_pager_dealloc(vm_object_t object)
 265 {
 266         struct vnode *vp;
 267         int refs;
 268
 269         vp = object->handle;
 270         if (vp == NULL)
 271                 panic("vnode_pager_dealloc: pager already dealloced");
 272
 273         VM_OBJECT_ASSERT_WLOCKED(object);
 274         vm_object_pip_wait(object, "vnpdea");
 275         refs = object->ref_count;
 276
 277         object->handle = NULL;
 278         object->type = OBJT_DEAD;
 279         if (object->flags & OBJ_DISCONNECTWNT) {
 280                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 281                 wakeup(object);
 282         }
 283         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 284         if (object->un_pager.vnp.writemappings > 0) {
 285                 object->un_pager.vnp.writemappings = 0;
 286                 VOP_ADD_WRITECOUNT(vp, -1);
 287                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
 288                     __func__, vp, vp->v_writecount);
 289         }
 290         vp->v_object = NULL;
 291         VOP_UNSET_TEXT(vp);
 292         VM_OBJECT_WUNLOCK(object);
 293         while (refs-- > 0)
 294                 vunref(vp);
 295         VM_OBJECT_WLOCK(object);
 296 }
 297
 298 static boolean_t
 299 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 300     int *after)
 301 {
 302         struct vnode *vp = object->handle;
 303         daddr_t bn;
 304         int err;
 305         daddr_t reqblock;
 306         int poff;
 307         int bsize;
 308         int pagesperblock, blocksperpage;
 309
 310         VM_OBJECT_ASSERT_WLOCKED(object);
 311         /*
 312          * If no vp or vp is doomed or marked transparent to VM, we do not
 313          * have the page.
 314          */
 315         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 316                 return FALSE;
 317         /*
 318          * If the offset is beyond end of file we do
 319          * not have the page.
 320          */
 321         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 322                 return FALSE;
 323
 324         bsize = vp->v_mount->mnt_stat.f_iosize;
 325         pagesperblock = bsize / PAGE_SIZE;
 326         blocksperpage = 0;
 327         if (pagesperblock > 0) {
 328                 reqblock = pindex / pagesperblock;
 329         } else {
 330                 blocksperpage = (PAGE_SIZE / bsize);
 331                 reqblock = pindex * blocksperpage;
 332         }
 333         VM_OBJECT_WUNLOCK(object);
 334         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 335         VM_OBJECT_WLOCK(object);
 336         if (err)
 337                 return TRUE;
 338         if (bn == -1)
 339                 return FALSE;
 340         if (pagesperblock > 0) {
 341                 poff = pindex - (reqblock * pagesperblock);
 342                 if (before) {
 343                         *before *= pagesperblock;
 344                         *before += poff;
 345                 }
 346                 if (after) {
 347                         /*
 348                          * The BMAP vop can report a partial block in the
 349                          * 'after', but must not report blocks after EOF.
 350                          * Assert the latter, and truncate 'after' in case
 351                          * of the former.
 352                          */
 353                         KASSERT((reqblock + *after) * pagesperblock <
 354                             roundup2(object->size, pagesperblock),
 355                             ("%s: reqblock %jd after %d size %ju", __func__,
 356                             (intmax_t )reqblock, *after,
 357                             (uintmax_t )object->size));
 358                         *after *= pagesperblock;
 359                         *after += pagesperblock - (poff + 1);
 360                         if (pindex + *after >= object->size)
 361                                 *after = object->size - 1 - pindex;
 362                 }
 363         } else {
 364                 if (before) {
 365                         *before /= blocksperpage;
 366                 }
 367
 368                 if (after) {
 369                         *after /= blocksperpage;
 370                 }
 371         }
 372         return TRUE;
 373 }
 374
 375 /*
 376  * Lets the VM system know about a change in size for a file.
 377  * We adjust our own internal size and flush any cached pages in
 378  * the associated object that are affected by the size change.
 379  *
 380  * Note: this routine may be invoked as a result of a pager put
 381  * operation (possibly at object termination time), so we must be careful.
 382  */
 383 void
 384 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
 385 {
 386         vm_object_t object;
 387         vm_page_t m;
 388         vm_pindex_t nobjsize;
 389
 390         if ((object = vp->v_object) == NULL)
 391                 return;
 392 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 393         VM_OBJECT_WLOCK(object);
 394         if (object->type == OBJT_DEAD) {
 395                 VM_OBJECT_WUNLOCK(object);
 396                 return;
 397         }
 398         KASSERT(object->type == OBJT_VNODE,
 399             ("not vnode-backed object %p", object));
 400         if (nsize == object->un_pager.vnp.vnp_size) {
 401                 /*
 402                  * Hasn't changed size
 403                  */
 404                 VM_OBJECT_WUNLOCK(object);
 405                 return;
 406         }
 407         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 408         if (nsize < object->un_pager.vnp.vnp_size) {
 409                 /*
 410                  * File has shrunk. Toss any cached pages beyond the new EOF.
 411                  */
 412                 if (nobjsize < object->size)
 413                         vm_object_page_remove(object, nobjsize, object->size,
 414                             0);
 415                 /*
 416                  * this gets rid of garbage at the end of a page that is now
 417                  * only partially backed by the vnode.
 418                  *
 419                  * XXX for some reason (I don't know yet), if we take a
 420                  * completely invalid page and mark it partially valid
 421                  * it can screw up NFS reads, so we don't allow the case.
 422                  */
 423                 if ((nsize & PAGE_MASK) &&
 424                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 425                     m->valid != 0) {
 426                         int base = (int)nsize & PAGE_MASK;
 427                         int size = PAGE_SIZE - base;
 428
 429                         /*
 430                          * Clear out partial-page garbage in case
 431                          * the page has been mapped.
 432                          */
 433                         pmap_zero_page_area(m, base, size);
 434
 435                         /*
 436                          * Update the valid bits to reflect the blocks that
 437                          * have been zeroed.  Some of these valid bits may
 438                          * have already been set.
 439                          */
 440                         vm_page_set_valid_range(m, base, size);
 441
 442                         /*
 443                          * Round "base" to the next block boundary so that the
 444                          * dirty bit for a partially zeroed block is not
 445                          * cleared.
 446                          */
 447                         base = roundup2(base, DEV_BSIZE);
 448
 449                         /*
 450                          * Clear out partial-page dirty bits.
 451                          *
 452                          * note that we do not clear out the valid
 453                          * bits.  This would prevent bogus_page
 454                          * replacement from working properly.
 455                          */
 456                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 457                 } else if ((nsize & PAGE_MASK) &&
 458                     vm_page_is_cached(object, OFF_TO_IDX(nsize))) {
 459                         vm_page_cache_free(object, OFF_TO_IDX(nsize),
 460                             nobjsize);
 461                 }
 462         }
 463         object->un_pager.vnp.vnp_size = nsize;
 464         object->size = nobjsize;
 465         VM_OBJECT_WUNLOCK(object);
 466 }
 467
 468 /*
 469  * calculate the linear (byte) disk address of specified virtual
 470  * file address
 471  */
 472 static int
 473 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 474     int *run)
 475 {
 476         int bsize;
 477         int err;
 478         daddr_t vblock;
 479         daddr_t voffset;
 480
 481         if (address < 0)
 482                 return -1;
 483
 484         if (vp->v_iflag & VI_DOOMED)
 485                 return -1;
 486
 487         bsize = vp->v_mount->mnt_stat.f_iosize;
 488         vblock = address / bsize;
 489         voffset = address % bsize;
 490
 491         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 492         if (err == 0) {
 493                 if (*rtaddress != -1)
 494                         *rtaddress += voffset / DEV_BSIZE;
 495                 if (run) {
 496                         *run += 1;
 497                         *run *= bsize/PAGE_SIZE;
 498                         *run -= voffset/PAGE_SIZE;
 499                 }
 500         }
 501
 502         return (err);
 503 }
 504
 505 /*
 506  * small block filesystem vnode pager input
 507  */
 508 static int
 509 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
 510 {
 511         struct vnode *vp;
 512         struct bufobj *bo;
 513         struct buf *bp;
 514         struct sf_buf *sf;
 515         daddr_t fileaddr;
 516         vm_offset_t bsize;
 517         vm_page_bits_t bits;
 518         int error, i;
 519
 520         error = 0;
 521         vp = object->handle;
 522         if (vp->v_iflag & VI_DOOMED)
 523                 return VM_PAGER_BAD;
 524
 525         bsize = vp->v_mount->mnt_stat.f_iosize;
 526
 527         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 528
 529         sf = sf_buf_alloc(m, 0);
 530
 531         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 532                 vm_ooffset_t address;
 533
 534                 bits = vm_page_bits(i * bsize, bsize);
 535                 if (m->valid & bits)
 536                         continue;
 537
 538                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 539                 if (address >= object->un_pager.vnp.vnp_size) {
 540                         fileaddr = -1;
 541                 } else {
 542                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 543                         if (error)
 544                                 break;
 545                 }
 546                 if (fileaddr != -1) {
 547                         bp = getpbuf(&vnode_pbuf_freecnt);
 548
 549                         /* build a minimal buffer header */
 550                         bp->b_iocmd = BIO_READ;
 551                         bp->b_iodone = bdone;
 552                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 553                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 554                         bp->b_rcred = crhold(curthread->td_ucred);
 555                         bp->b_wcred = crhold(curthread->td_ucred);
 556                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 557                         bp->b_blkno = fileaddr;
 558                         pbgetbo(bo, bp);
 559                         bp->b_vp = vp;
 560                         bp->b_bcount = bsize;
 561                         bp->b_bufsize = bsize;
 562                         bp->b_runningbufspace = bp->b_bufsize;
 563                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 564
 565                         /* do the input */
 566                         bp->b_iooffset = dbtob(bp->b_blkno);
 567                         bstrategy(bp);
 568
 569                         bwait(bp, PVM, "vnsrd");
 570
 571                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 572                                 error = EIO;
 573
 574                         /*
 575                          * free the buffer header back to the swap buffer pool
 576                          */
 577                         bp->b_vp = NULL;
 578                         pbrelbo(bp);
 579                         relpbuf(bp, &vnode_pbuf_freecnt);
 580                         if (error)
 581                                 break;
 582                 } else
 583                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 584                 KASSERT((m->dirty & bits) == 0,
 585                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 586                 VM_OBJECT_WLOCK(object);
 587                 m->valid |= bits;
 588                 VM_OBJECT_WUNLOCK(object);
 589         }
 590         sf_buf_free(sf);
 591         if (error) {
 592                 return VM_PAGER_ERROR;
 593         }
 594         return VM_PAGER_OK;
 595 }
 596
 597 /*
 598  * old style vnode pager input routine
 599  */
 600 static int
 601 vnode_pager_input_old(vm_object_t object, vm_page_t m)
 602 {
 603         struct uio auio;
 604         struct iovec aiov;
 605         int error;
 606         int size;
 607         struct sf_buf *sf;
 608         struct vnode *vp;
 609
 610         VM_OBJECT_ASSERT_WLOCKED(object);
 611         error = 0;
 612
 613         /*
 614          * Return failure if beyond current EOF
 615          */
 616         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 617                 return VM_PAGER_BAD;
 618         } else {
 619                 size = PAGE_SIZE;
 620                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 621                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 622                 vp = object->handle;
 623                 VM_OBJECT_WUNLOCK(object);
 624
 625                 /*
 626                  * Allocate a kernel virtual address and initialize so that
 627                  * we can use VOP_READ/WRITE routines.
 628                  */
 629                 sf = sf_buf_alloc(m, 0);
 630
 631                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 632                 aiov.iov_len = size;
 633                 auio.uio_iov = &aiov;
 634                 auio.uio_iovcnt = 1;
 635                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 636                 auio.uio_segflg = UIO_SYSSPACE;
 637                 auio.uio_rw = UIO_READ;
 638                 auio.uio_resid = size;
 639                 auio.uio_td = curthread;
 640
 641                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 642                 if (!error) {
 643                         int count = size - auio.uio_resid;
 644
 645                         if (count == 0)
 646                                 error = EINVAL;
 647                         else if (count != PAGE_SIZE)
 648                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 649                                     PAGE_SIZE - count);
 650                 }
 651                 sf_buf_free(sf);
 652
 653                 VM_OBJECT_WLOCK(object);
 654         }
 655         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 656         if (!error)
 657                 m->valid = VM_PAGE_BITS_ALL;
 658         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 659 }
 660
 661 /*
 662  * generic vnode pager input routine
 663  */
 664
 665 /*
 666  * Local media VFS's that do not implement their own VOP_GETPAGES
 667  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 668  * to implement the previous behaviour.
 669  *
 670  * All other FS's should use the bypass to get to the local media
 671  * backing vp's VOP_GETPAGES.
 672  */
 673 static int
 674 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
 675     int *rahead)
 676 {
 677         struct vnode *vp;
 678         int rtval;
 679
 680         vp = object->handle;
 681         VM_OBJECT_WUNLOCK(object);
 682         rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
 683         KASSERT(rtval != EOPNOTSUPP,
 684             ("vnode_pager: FS getpages not implemented\n"));
 685         VM_OBJECT_WLOCK(object);
 686         return rtval;
 687 }
 688
 689 static int
 690 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
 691     int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
 692 {
 693         struct vnode *vp;
 694         int rtval;
 695
 696         vp = object->handle;
 697         VM_OBJECT_WUNLOCK(object);
 698         rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
 699         KASSERT(rtval != EOPNOTSUPP,
 700             ("vnode_pager: FS getpages_async not implemented\n"));
 701         VM_OBJECT_WLOCK(object);
 702         return (rtval);
 703 }
 704
 705 /*
 706  * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
 707  * local filesystems, where partially valid pages can only occur at
 708  * the end of file.
 709  */
 710 int
 711 vnode_pager_local_getpages(struct vop_getpages_args *ap)
 712 {
 713
 714         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 715             ap->a_rbehind, ap->a_rahead, NULL, NULL));
 716 }
 717
 718 int
 719 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
 720 {
 721
 722         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 723             ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg));
 724 }
 725
 726 /*
 727  * This is now called from local media FS's to operate against their
 728  * own vnodes if they fail to implement VOP_GETPAGES.
 729  */
 730 int
 731 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
 732     int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
 733 {
 734         vm_object_t object;
 735         struct bufobj *bo;
 736         struct buf *bp;
 737         off_t foff;
 738         int bsize, pagesperblock, *freecnt;
 739         int error, before, after, rbehind, rahead, poff, i;
 740         int bytecount, secmask;
 741
 742         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 743             ("%s does not support devices", __func__));
 744
 745         if (vp->v_iflag & VI_DOOMED)
 746                 return (VM_PAGER_BAD);
 747
 748         object = vp->v_object;
 749         foff = IDX_TO_OFF(m[0]->pindex);
 750         bsize = vp->v_mount->mnt_stat.f_iosize;
 751         pagesperblock = bsize / PAGE_SIZE;
 752
 753         KASSERT(foff < object->un_pager.vnp.vnp_size,
 754             ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
 755         KASSERT(count <= sizeof(bp->b_pages),
 756             ("%s: requested %d pages", __func__, count));
 757
 758         /*
 759          * The last page has valid blocks.  Invalid part can only
 760          * exist at the end of file, and the page is made fully valid
 761          * by zeroing in vm_pager_get_pages().
 762          */
 763         if (m[count - 1]->valid != 0 && --count == 0) {
 764                 if (iodone != NULL)
 765                         iodone(arg, m, 1, 0);
 766                 return (VM_PAGER_OK);
 767         }
 768
 769         /*
 770          * Synchronous and asynchronous paging operations use different
 771          * free pbuf counters.  This is done to avoid asynchronous requests
 772          * to consume all pbufs.
 773          * Allocate the pbuf at the very beginning of the function, so that
 774          * if we are low on certain kind of pbufs don't even proceed to BMAP,
 775          * but sleep.
 776          */
 777         freecnt = iodone != NULL ?
 778             &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
 779         bp = getpbuf(freecnt);
 780
 781         /*
 782          * Get the underlying device blocks for the file with VOP_BMAP().
 783          * If the file system doesn't support VOP_BMAP, use old way of
 784          * getting pages via VOP_READ.
 785          */
 786         error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
 787         if (error == EOPNOTSUPP) {
 788                 relpbuf(bp, freecnt);
 789                 VM_OBJECT_WLOCK(object);
 790                 for (i = 0; i < count; i++) {
 791                         PCPU_INC(cnt.v_vnodein);
 792                         PCPU_INC(cnt.v_vnodepgsin);
 793                         error = vnode_pager_input_old(object, m[i]);
 794                         if (error)
 795                                 break;
 796                 }
 797                 VM_OBJECT_WUNLOCK(object);
 798                 return (error);
 799         } else if (error != 0) {
 800                 relpbuf(bp, freecnt);
 801                 return (VM_PAGER_ERROR);
 802         }
 803
 804         /*
 805          * If the file system supports BMAP, but blocksize is smaller
 806          * than a page size, then use special small filesystem code.
 807          */
 808         if (pagesperblock == 0) {
 809                 relpbuf(bp, freecnt);
 810                 for (i = 0; i < count; i++) {
 811                         PCPU_INC(cnt.v_vnodein);
 812                         PCPU_INC(cnt.v_vnodepgsin);
 813                         error = vnode_pager_input_smlfs(object, m[i]);
 814                         if (error)
 815                                 break;
 816                 }
 817                 return (error);
 818         }
 819
 820         /*
 821          * A sparse file can be encountered only for a single page request,
 822          * which may not be preceeded by call to vm_pager_haspage().
 823          */
 824         if (bp->b_blkno == -1) {
 825                 KASSERT(count == 1,
 826                     ("%s: array[%d] request to a sparse file %p", __func__,
 827                     count, vp));
 828                 relpbuf(bp, freecnt);
 829                 pmap_zero_page(m[0]);
 830                 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
 831                     __func__, m[0]));
 832                 VM_OBJECT_WLOCK(object);
 833                 m[0]->valid = VM_PAGE_BITS_ALL;
 834                 VM_OBJECT_WUNLOCK(object);
 835                 return (VM_PAGER_OK);
 836         }
 837
 838         bp->b_blkno += (foff % bsize) / DEV_BSIZE;
 839
 840         /* Recalculate blocks available after/before to pages. */
 841         poff = (foff % bsize) / PAGE_SIZE;
 842         before *= pagesperblock;
 843         before += poff;
 844         after *= pagesperblock;
 845         after += pagesperblock - (poff + 1);
 846         if (m[0]->pindex + after >= object->size)
 847                 after = object->size - 1 - m[0]->pindex;
 848         KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
 849             __func__, count, after + 1));
 850         after -= count - 1;
 851
 852         /* Trim requested rbehind/rahead to possible values. */
 853         rbehind = a_rbehind ? *a_rbehind : 0;
 854         rahead = a_rahead ? *a_rahead : 0;
 855         rbehind = min(rbehind, before);
 856         rbehind = min(rbehind, m[0]->pindex);
 857         rahead = min(rahead, after);
 858         rahead = min(rahead, object->size - m[count - 1]->pindex);
 859         KASSERT(rbehind + rahead + count <= sizeof(bp->b_pages),
 860             ("%s: behind %d ahead %d count %d", __func__,
 861             rbehind, rahead, count));
 862
 863         /*
 864          * Fill in the bp->b_pages[] array with requested and optional
 865          * read behind or read ahead pages.  Read behind pages are looked
 866          * up in a backward direction, down to a first cached page.  Same
 867          * for read ahead pages, but there is no need to shift the array
 868          * in case of encountering a cached page.
 869          */
 870         i = bp->b_npages = 0;
 871         if (rbehind) {
 872                 vm_pindex_t startpindex, tpindex;
 873                 vm_page_t p;
 874
 875                 VM_OBJECT_WLOCK(object);
 876                 startpindex = m[0]->pindex - rbehind;
 877                 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
 878                     p->pindex >= startpindex)
 879                         startpindex = p->pindex + 1;
 880
 881                 /* tpindex is unsigned; beware of numeric underflow. */
 882                 for (tpindex = m[0]->pindex - 1;
 883                     tpindex >= startpindex && tpindex < m[0]->pindex;
 884                     tpindex--, i++) {
 885                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 886                             VM_ALLOC_IFNOTCACHED);
 887                         if (p == NULL) {
 888                                 /* Shift the array. */
 889                                 for (int j = 0; j < i; j++)
 890                                         bp->b_pages[j] = bp->b_pages[j +
 891                                             tpindex + 1 - startpindex];
 892                                 break;
 893                         }
 894                         bp->b_pages[tpindex - startpindex] = p;
 895                 }
 896
 897                 bp->b_pgbefore = i;
 898                 bp->b_npages += i;
 899                 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
 900         } else
 901                 bp->b_pgbefore = 0;
 902
 903         /* Requested pages. */
 904         for (int j = 0; j < count; j++, i++)
 905                 bp->b_pages[i] = m[j];
 906         bp->b_npages += count;
 907
 908         if (rahead) {
 909                 vm_pindex_t endpindex, tpindex;
 910                 vm_page_t p;
 911
 912                 if (!VM_OBJECT_WOWNED(object))
 913                         VM_OBJECT_WLOCK(object);
 914                 endpindex = m[count - 1]->pindex + rahead + 1;
 915                 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
 916                     p->pindex < endpindex)
 917                         endpindex = p->pindex;
 918                 if (endpindex > object->size)
 919                         endpindex = object->size;
 920
 921                 for (tpindex = m[count - 1]->pindex + 1;
 922                     tpindex < endpindex; i++, tpindex++) {
 923                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 924                             VM_ALLOC_IFNOTCACHED);
 925                         if (p == NULL)
 926                                 break;
 927                         bp->b_pages[i] = p;
 928                 }
 929
 930                 bp->b_pgafter = i - bp->b_npages;
 931                 bp->b_npages = i;
 932         } else
 933                 bp->b_pgafter = 0;
 934
 935         if (VM_OBJECT_WOWNED(object))
 936                 VM_OBJECT_WUNLOCK(object);
 937
 938         /* Report back actual behind/ahead read. */
 939         if (a_rbehind)
 940                 *a_rbehind = bp->b_pgbefore;
 941         if (a_rahead)
 942                 *a_rahead = bp->b_pgafter;
 943
 944         KASSERT(bp->b_npages <= sizeof(bp->b_pages),
 945             ("%s: buf %p overflowed", __func__, bp));
 946
 947         /*
 948          * Recalculate first offset and bytecount with regards to read behind.
 949          * Truncate bytecount to vnode real size and round up physical size
 950          * for real devices.
 951          */
 952         foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
 953         bytecount = bp->b_npages << PAGE_SHIFT;
 954         if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
 955                 bytecount = object->un_pager.vnp.vnp_size - foff;
 956         secmask = bo->bo_bsize - 1;
 957         KASSERT(secmask < PAGE_SIZE && secmask > 0,
 958             ("%s: sector size %d too large", __func__, secmask + 1));
 959         bytecount = (bytecount + secmask) & ~secmask;
 960
 961         /*
 962          * And map the pages to be read into the kva, if the filesystem
 963          * requires mapped buffers.
 964          */
 965         if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
 966             unmapped_buf_allowed) {
 967                 bp->b_data = unmapped_buf;
 968                 bp->b_offset = 0;
 969         } else {
 970                 bp->b_data = bp->b_kvabase;
 971                 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
 972         }
 973
 974         /* Build a minimal buffer header. */
 975         bp->b_iocmd = BIO_READ;
 976         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 977         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 978         bp->b_rcred = crhold(curthread->td_ucred);
 979         bp->b_wcred = crhold(curthread->td_ucred);
 980         pbgetbo(bo, bp);
 981         bp->b_vp = vp;
 982         bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
 983         bp->b_iooffset = dbtob(bp->b_blkno);
 984
 985         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 986         PCPU_INC(cnt.v_vnodein);
 987         PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages);
 988
 989         if (iodone != NULL) { /* async */
 990                 bp->b_pgiodone = iodone;
 991                 bp->b_caller1 = arg;
 992                 bp->b_iodone = vnode_pager_generic_getpages_done_async;
 993                 bp->b_flags |= B_ASYNC;
 994                 BUF_KERNPROC(bp);
 995                 bstrategy(bp);
 996                 return (VM_PAGER_OK);
 997         } else {
 998                 bp->b_iodone = bdone;
 999                 bstrategy(bp);
1000                 bwait(bp, PVM, "vnread");
1001                 error = vnode_pager_generic_getpages_done(bp);
1002                 for (i = 0; i < bp->b_npages; i++)
1003                         bp->b_pages[i] = NULL;
1004                 bp->b_vp = NULL;
1005                 pbrelbo(bp);
1006                 relpbuf(bp, &vnode_pbuf_freecnt);
1007                 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
1008         }
1009 }
1010
1011 static void
1012 vnode_pager_generic_getpages_done_async(struct buf *bp)
1013 {
1014         int error;
1015
1016         error = vnode_pager_generic_getpages_done(bp);
1017         /* Run the iodone upon the requested range. */
1018         bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
1019             bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
1020         for (int i = 0; i < bp->b_npages; i++)
1021                 bp->b_pages[i] = NULL;
1022         bp->b_vp = NULL;
1023         pbrelbo(bp);
1024         relpbuf(bp, &vnode_async_pbuf_freecnt);
1025 }
1026
1027 static int
1028 vnode_pager_generic_getpages_done(struct buf *bp)
1029 {
1030         vm_object_t object;
1031         off_t tfoff, nextoff;
1032         int i, error;
1033
1034         error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0;
1035         object = bp->b_vp->v_object;
1036
1037         if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
1038                 if (!buf_mapped(bp)) {
1039                         bp->b_data = bp->b_kvabase;
1040                         pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
1041                             bp->b_npages);
1042                 }
1043                 bzero(bp->b_data + bp->b_bcount,
1044                     PAGE_SIZE * bp->b_npages - bp->b_bcount);
1045         }
1046         if (buf_mapped(bp)) {
1047                 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1048                 bp->b_data = unmapped_buf;
1049         }
1050
1051         VM_OBJECT_WLOCK(object);
1052         for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1053             i < bp->b_npages; i++, tfoff = nextoff) {
1054                 vm_page_t mt;
1055
1056                 nextoff = tfoff + PAGE_SIZE;
1057                 mt = bp->b_pages[i];
1058
1059                 if (nextoff <= object->un_pager.vnp.vnp_size) {
1060                         /*
1061                          * Read filled up entire page.
1062                          */
1063                         mt->valid = VM_PAGE_BITS_ALL;
1064                         KASSERT(mt->dirty == 0,
1065                             ("%s: page %p is dirty", __func__, mt));
1066                         KASSERT(!pmap_page_is_mapped(mt),
1067                             ("%s: page %p is mapped", __func__, mt));
1068                 } else {
1069                         /*
1070                          * Read did not fill up entire page.
1071                          *
1072                          * Currently we do not set the entire page valid,
1073                          * we just try to clear the piece that we couldn't
1074                          * read.
1075                          */
1076                         vm_page_set_valid_range(mt, 0,
1077                             object->un_pager.vnp.vnp_size - tfoff);
1078                         KASSERT((mt->dirty & vm_page_bits(0,
1079                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
1080                             ("%s: page %p is dirty", __func__, mt));
1081                 }
1082
1083                 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
1084                         vm_page_readahead_finish(mt);
1085         }
1086         VM_OBJECT_WUNLOCK(object);
1087         if (error != 0)
1088                 printf("%s: I/O read error %d\n", __func__, error);
1089
1090         return (error);
1091 }
1092
1093 /*
1094  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1095  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1096  * vnode_pager_generic_putpages() to implement the previous behaviour.
1097  *
1098  * All other FS's should use the bypass to get to the local media
1099  * backing vp's VOP_PUTPAGES.
1100  */
1101 static void
1102 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1103     int flags, int *rtvals)
1104 {
1105         int rtval;
1106         struct vnode *vp;
1107         int bytes = count * PAGE_SIZE;
1108
1109         /*
1110          * Force synchronous operation if we are extremely low on memory
1111          * to prevent a low-memory deadlock.  VOP operations often need to
1112          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1113          * operation ).  The swapper handles the case by limiting the amount
1114          * of asynchronous I/O, but that sort of solution doesn't scale well
1115          * for the vnode pager without a lot of work.
1116          *
1117          * Also, the backing vnode's iodone routine may not wake the pageout
1118          * daemon up.  This should be probably be addressed XXX.
1119          */
1120
1121         if (vm_cnt.v_free_count + vm_cnt.v_cache_count <
1122             vm_cnt.v_pageout_free_min)
1123                 flags |= VM_PAGER_PUT_SYNC;
1124
1125         /*
1126          * Call device-specific putpages function
1127          */
1128         vp = object->handle;
1129         VM_OBJECT_WUNLOCK(object);
1130         rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
1131         KASSERT(rtval != EOPNOTSUPP,
1132             ("vnode_pager: stale FS putpages\n"));
1133         VM_OBJECT_WLOCK(object);
1134 }
1135
1136
1137 /*
1138  * This is now called from local media FS's to operate against their
1139  * own vnodes if they fail to implement VOP_PUTPAGES.
1140  *
1141  * This is typically called indirectly via the pageout daemon and
1142  * clustering has already typically occured, so in general we ask the
1143  * underlying filesystem to write the data out asynchronously rather
1144  * then delayed.
1145  */
1146 int
1147 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1148     int flags, int *rtvals)
1149 {
1150         int i;
1151         vm_object_t object;
1152         vm_page_t m;
1153         int count;
1154
1155         int maxsize, ncount;
1156         vm_ooffset_t poffset;
1157         struct uio auio;
1158         struct iovec aiov;
1159         int error;
1160         int ioflags;
1161         int ppscheck = 0;
1162         static struct timeval lastfail;
1163         static int curfail;
1164
1165         object = vp->v_object;
1166         count = bytecount / PAGE_SIZE;
1167
1168         for (i = 0; i < count; i++)
1169                 rtvals[i] = VM_PAGER_ERROR;
1170
1171         if ((int64_t)ma[0]->pindex < 0) {
1172                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1173                     (long)ma[0]->pindex, (u_long)ma[0]->dirty);
1174                 rtvals[0] = VM_PAGER_BAD;
1175                 return VM_PAGER_BAD;
1176         }
1177
1178         maxsize = count * PAGE_SIZE;
1179         ncount = count;
1180
1181         poffset = IDX_TO_OFF(ma[0]->pindex);
1182
1183         /*
1184          * If the page-aligned write is larger then the actual file we
1185          * have to invalidate pages occuring beyond the file EOF.  However,
1186          * there is an edge case where a file may not be page-aligned where
1187          * the last page is partially invalid.  In this case the filesystem
1188          * may not properly clear the dirty bits for the entire page (which
1189          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1190          * With the page locked we are free to fix-up the dirty bits here.
1191          *
1192          * We do not under any circumstances truncate the valid bits, as
1193          * this will screw up bogus page replacement.
1194          */
1195         VM_OBJECT_WLOCK(object);
1196         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1197                 if (object->un_pager.vnp.vnp_size > poffset) {
1198                         int pgoff;
1199
1200                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1201                         ncount = btoc(maxsize);
1202                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1203                                 /*
1204                                  * If the object is locked and the following
1205                                  * conditions hold, then the page's dirty
1206                                  * field cannot be concurrently changed by a
1207                                  * pmap operation.
1208                                  */
1209                                 m = ma[ncount - 1];
1210                                 vm_page_assert_sbusied(m);
1211                                 KASSERT(!pmap_page_is_write_mapped(m),
1212                 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1213                                 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1214                                     pgoff);
1215                         }
1216                 } else {
1217                         maxsize = 0;
1218                         ncount = 0;
1219                 }
1220                 if (ncount < count) {
1221                         for (i = ncount; i < count; i++) {
1222                                 rtvals[i] = VM_PAGER_BAD;
1223                         }
1224                 }
1225         }
1226         VM_OBJECT_WUNLOCK(object);
1227
1228         /*
1229          * pageouts are already clustered, use IO_ASYNC to force a bawrite()
1230          * rather then a bdwrite() to prevent paging I/O from saturating
1231          * the buffer cache.  Dummy-up the sequential heuristic to cause
1232          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
1233          * the system decides how to cluster.
1234          */
1235         ioflags = IO_VMIO;
1236         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1237                 ioflags |= IO_SYNC;
1238         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1239                 ioflags |= IO_ASYNC;
1240         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1241         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1242
1243         aiov.iov_base = (caddr_t) 0;
1244         aiov.iov_len = maxsize;
1245         auio.uio_iov = &aiov;
1246         auio.uio_iovcnt = 1;
1247         auio.uio_offset = poffset;
1248         auio.uio_segflg = UIO_NOCOPY;
1249         auio.uio_rw = UIO_WRITE;
1250         auio.uio_resid = maxsize;
1251         auio.uio_td = (struct thread *) 0;
1252         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1253         PCPU_INC(cnt.v_vnodeout);
1254         PCPU_ADD(cnt.v_vnodepgsout, ncount);
1255
1256         if (error) {
1257                 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1258                         printf("vnode_pager_putpages: I/O error %d\n", error);
1259         }
1260         if (auio.uio_resid) {
1261                 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1262                         printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1263                             auio.uio_resid, (u_long)ma[0]->pindex);
1264         }
1265         for (i = 0; i < ncount; i++) {
1266                 rtvals[i] = VM_PAGER_OK;
1267         }
1268         return rtvals[0];
1269 }
1270
1271 void
1272 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written)
1273 {
1274         vm_object_t obj;
1275         int i, pos;
1276
1277         if (written == 0)
1278                 return;
1279         obj = ma[0]->object;
1280         VM_OBJECT_WLOCK(obj);
1281         for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1282                 if (pos < trunc_page(written)) {
1283                         rtvals[i] = VM_PAGER_OK;
1284                         vm_page_undirty(ma[i]);
1285                 } else {
1286                         /* Partially written page. */
1287                         rtvals[i] = VM_PAGER_AGAIN;
1288                         vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1289                 }
1290         }
1291         VM_OBJECT_WUNLOCK(obj);
1292 }
1293
1294 void
1295 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1296     vm_offset_t end)
1297 {
1298         struct vnode *vp;
1299         vm_ooffset_t old_wm;
1300
1301         VM_OBJECT_WLOCK(object);
1302         if (object->type != OBJT_VNODE) {
1303                 VM_OBJECT_WUNLOCK(object);
1304                 return;
1305         }
1306         old_wm = object->un_pager.vnp.writemappings;
1307         object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1308         vp = object->handle;
1309         if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1310                 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1311                 VOP_ADD_WRITECOUNT(vp, 1);
1312                 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1313                     __func__, vp, vp->v_writecount);
1314         } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1315                 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1316                 VOP_ADD_WRITECOUNT(vp, -1);
1317                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1318                     __func__, vp, vp->v_writecount);
1319         }
1320         VM_OBJECT_WUNLOCK(object);
1321 }
1322
1323 void
1324 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1325     vm_offset_t end)
1326 {
1327         struct vnode *vp;
1328         struct mount *mp;
1329         vm_offset_t inc;
1330
1331         VM_OBJECT_WLOCK(object);
1332
1333         /*
1334          * First, recheck the object type to account for the race when
1335          * the vnode is reclaimed.
1336          */
1337         if (object->type != OBJT_VNODE) {
1338                 VM_OBJECT_WUNLOCK(object);
1339                 return;
1340         }
1341
1342         /*
1343          * Optimize for the case when writemappings is not going to
1344          * zero.
1345          */
1346         inc = end - start;
1347         if (object->un_pager.vnp.writemappings != inc) {
1348                 object->un_pager.vnp.writemappings -= inc;
1349                 VM_OBJECT_WUNLOCK(object);
1350                 return;
1351         }
1352
1353         vp = object->handle;
1354         vhold(vp);
1355         VM_OBJECT_WUNLOCK(object);
1356         mp = NULL;
1357         vn_start_write(vp, &mp, V_WAIT);
1358         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1359
1360         /*
1361          * Decrement the object's writemappings, by swapping the start
1362          * and end arguments for vnode_pager_update_writecount().  If
1363          * there was not a race with vnode reclaimation, then the
1364          * vnode's v_writecount is decremented.
1365          */
1366         vnode_pager_update_writecount(object, end, start);
1367         VOP_UNLOCK(vp, 0);
1368         vdrop(vp);
1369         if (mp != NULL)
1370                 vn_finished_write(mp);
1371 }