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         umtx_shm_object_terminated(obj);
 168         if (obj->ref_count == 0) {
 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_WUNLOCK(obj);
 176         } else {
 177                 /*
 178                  * Woe to the process that tries to page now :-).
 179                  */
 180                 vm_pager_deallocate(obj);
 181                 VM_OBJECT_WUNLOCK(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, struct ucred *cred)
 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         /*
 209          * If the object is being terminated, wait for it to
 210          * go away.
 211          */
 212 retry:
 213         while ((object = vp->v_object) != NULL) {
 214                 VM_OBJECT_WLOCK(object);
 215                 if ((object->flags & OBJ_DEAD) == 0)
 216                         break;
 217                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 218                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
 219         }
 220
 221         KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
 222
 223         if (object == NULL) {
 224                 /*
 225                  * Add an object of the appropriate size
 226                  */
 227                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 228
 229                 object->un_pager.vnp.vnp_size = size;
 230                 object->un_pager.vnp.writemappings = 0;
 231
 232                 object->handle = handle;
 233                 VI_LOCK(vp);
 234                 if (vp->v_object != NULL) {
 235                         /*
 236                          * Object has been created while we were sleeping
 237                          */
 238                         VI_UNLOCK(vp);
 239                         VM_OBJECT_WLOCK(object);
 240                         KASSERT(object->ref_count == 1,
 241                             ("leaked ref %p %d", object, object->ref_count));
 242                         object->type = OBJT_DEAD;
 243                         object->ref_count = 0;
 244                         VM_OBJECT_WUNLOCK(object);
 245                         vm_object_destroy(object);
 246                         goto retry;
 247                 }
 248                 vp->v_object = object;
 249                 VI_UNLOCK(vp);
 250         } else {
 251                 object->ref_count++;
 252 #if VM_NRESERVLEVEL > 0
 253                 vm_object_color(object, 0);
 254 #endif
 255                 VM_OBJECT_WUNLOCK(object);
 256         }
 257         vref(vp);
 258         return (object);
 259 }
 260
 261 /*
 262  *      The object must be locked.
 263  */
 264 static void
 265 vnode_pager_dealloc(vm_object_t object)
 266 {
 267         struct vnode *vp;
 268         int refs;
 269
 270         vp = object->handle;
 271         if (vp == NULL)
 272                 panic("vnode_pager_dealloc: pager already dealloced");
 273
 274         VM_OBJECT_ASSERT_WLOCKED(object);
 275         vm_object_pip_wait(object, "vnpdea");
 276         refs = object->ref_count;
 277
 278         object->handle = NULL;
 279         object->type = OBJT_DEAD;
 280         if (object->flags & OBJ_DISCONNECTWNT) {
 281                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 282                 wakeup(object);
 283         }
 284         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 285         if (object->un_pager.vnp.writemappings > 0) {
 286                 object->un_pager.vnp.writemappings = 0;
 287                 VOP_ADD_WRITECOUNT(vp, -1);
 288                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
 289                     __func__, vp, vp->v_writecount);
 290         }
 291         vp->v_object = NULL;
 292         VOP_UNSET_TEXT(vp);
 293         VM_OBJECT_WUNLOCK(object);
 294         while (refs-- > 0)
 295                 vunref(vp);
 296         VM_OBJECT_WLOCK(object);
 297 }
 298
 299 static boolean_t
 300 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 301     int *after)
 302 {
 303         struct vnode *vp = object->handle;
 304         daddr_t bn;
 305         int err;
 306         daddr_t reqblock;
 307         int poff;
 308         int bsize;
 309         int pagesperblock, blocksperpage;
 310
 311         VM_OBJECT_ASSERT_WLOCKED(object);
 312         /*
 313          * If no vp or vp is doomed or marked transparent to VM, we do not
 314          * have the page.
 315          */
 316         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 317                 return FALSE;
 318         /*
 319          * If the offset is beyond end of file we do
 320          * not have the page.
 321          */
 322         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 323                 return FALSE;
 324
 325         bsize = vp->v_mount->mnt_stat.f_iosize;
 326         pagesperblock = bsize / PAGE_SIZE;
 327         blocksperpage = 0;
 328         if (pagesperblock > 0) {
 329                 reqblock = pindex / pagesperblock;
 330         } else {
 331                 blocksperpage = (PAGE_SIZE / bsize);
 332                 reqblock = pindex * blocksperpage;
 333         }
 334         VM_OBJECT_WUNLOCK(object);
 335         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 336         VM_OBJECT_WLOCK(object);
 337         if (err)
 338                 return TRUE;
 339         if (bn == -1)
 340                 return FALSE;
 341         if (pagesperblock > 0) {
 342                 poff = pindex - (reqblock * pagesperblock);
 343                 if (before) {
 344                         *before *= pagesperblock;
 345                         *before += poff;
 346                 }
 347                 if (after) {
 348                         /*
 349                          * The BMAP vop can report a partial block in the
 350                          * 'after', but must not report blocks after EOF.
 351                          * Assert the latter, and truncate 'after' in case
 352                          * of the former.
 353                          */
 354                         KASSERT((reqblock + *after) * pagesperblock <
 355                             roundup2(object->size, pagesperblock),
 356                             ("%s: reqblock %jd after %d size %ju", __func__,
 357                             (intmax_t )reqblock, *after,
 358                             (uintmax_t )object->size));
 359                         *after *= pagesperblock;
 360                         *after += pagesperblock - (poff + 1);
 361                         if (pindex + *after >= object->size)
 362                                 *after = object->size - 1 - pindex;
 363                 }
 364         } else {
 365                 if (before) {
 366                         *before /= blocksperpage;
 367                 }
 368
 369                 if (after) {
 370                         *after /= blocksperpage;
 371                 }
 372         }
 373         return TRUE;
 374 }
 375
 376 /*
 377  * Lets the VM system know about a change in size for a file.
 378  * We adjust our own internal size and flush any cached pages in
 379  * the associated object that are affected by the size change.
 380  *
 381  * Note: this routine may be invoked as a result of a pager put
 382  * operation (possibly at object termination time), so we must be careful.
 383  */
 384 void
 385 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
 386 {
 387         vm_object_t object;
 388         vm_page_t m;
 389         vm_pindex_t nobjsize;
 390
 391         if ((object = vp->v_object) == NULL)
 392                 return;
 393 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 394         VM_OBJECT_WLOCK(object);
 395         if (object->type == OBJT_DEAD) {
 396                 VM_OBJECT_WUNLOCK(object);
 397                 return;
 398         }
 399         KASSERT(object->type == OBJT_VNODE,
 400             ("not vnode-backed object %p", object));
 401         if (nsize == object->un_pager.vnp.vnp_size) {
 402                 /*
 403                  * Hasn't changed size
 404                  */
 405                 VM_OBJECT_WUNLOCK(object);
 406                 return;
 407         }
 408         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 409         if (nsize < object->un_pager.vnp.vnp_size) {
 410                 /*
 411                  * File has shrunk. Toss any cached pages beyond the new EOF.
 412                  */
 413                 if (nobjsize < object->size)
 414                         vm_object_page_remove(object, nobjsize, object->size,
 415                             0);
 416                 /*
 417                  * this gets rid of garbage at the end of a page that is now
 418                  * only partially backed by the vnode.
 419                  *
 420                  * XXX for some reason (I don't know yet), if we take a
 421                  * completely invalid page and mark it partially valid
 422                  * it can screw up NFS reads, so we don't allow the case.
 423                  */
 424                 if ((nsize & PAGE_MASK) &&
 425                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 426                     m->valid != 0) {
 427                         int base = (int)nsize & PAGE_MASK;
 428                         int size = PAGE_SIZE - base;
 429
 430                         /*
 431                          * Clear out partial-page garbage in case
 432                          * the page has been mapped.
 433                          */
 434                         pmap_zero_page_area(m, base, size);
 435
 436                         /*
 437                          * Update the valid bits to reflect the blocks that
 438                          * have been zeroed.  Some of these valid bits may
 439                          * have already been set.
 440                          */
 441                         vm_page_set_valid_range(m, base, size);
 442
 443                         /*
 444                          * Round "base" to the next block boundary so that the
 445                          * dirty bit for a partially zeroed block is not
 446                          * cleared.
 447                          */
 448                         base = roundup2(base, DEV_BSIZE);
 449
 450                         /*
 451                          * Clear out partial-page dirty bits.
 452                          *
 453                          * note that we do not clear out the valid
 454                          * bits.  This would prevent bogus_page
 455                          * replacement from working properly.
 456                          */
 457                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 458                 } else if ((nsize & PAGE_MASK) &&
 459                     vm_page_is_cached(object, OFF_TO_IDX(nsize))) {
 460                         vm_page_cache_free(object, OFF_TO_IDX(nsize),
 461                             nobjsize);
 462                 }
 463         }
 464         object->un_pager.vnp.vnp_size = nsize;
 465         object->size = nobjsize;
 466         VM_OBJECT_WUNLOCK(object);
 467 }
 468
 469 /*
 470  * calculate the linear (byte) disk address of specified virtual
 471  * file address
 472  */
 473 static int
 474 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 475     int *run)
 476 {
 477         int bsize;
 478         int err;
 479         daddr_t vblock;
 480         daddr_t voffset;
 481
 482         if (address < 0)
 483                 return -1;
 484
 485         if (vp->v_iflag & VI_DOOMED)
 486                 return -1;
 487
 488         bsize = vp->v_mount->mnt_stat.f_iosize;
 489         vblock = address / bsize;
 490         voffset = address % bsize;
 491
 492         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 493         if (err == 0) {
 494                 if (*rtaddress != -1)
 495                         *rtaddress += voffset / DEV_BSIZE;
 496                 if (run) {
 497                         *run += 1;
 498                         *run *= bsize/PAGE_SIZE;
 499                         *run -= voffset/PAGE_SIZE;
 500                 }
 501         }
 502
 503         return (err);
 504 }
 505
 506 /*
 507  * small block filesystem vnode pager input
 508  */
 509 static int
 510 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
 511 {
 512         struct vnode *vp;
 513         struct bufobj *bo;
 514         struct buf *bp;
 515         struct sf_buf *sf;
 516         daddr_t fileaddr;
 517         vm_offset_t bsize;
 518         vm_page_bits_t bits;
 519         int error, i;
 520
 521         error = 0;
 522         vp = object->handle;
 523         if (vp->v_iflag & VI_DOOMED)
 524                 return VM_PAGER_BAD;
 525
 526         bsize = vp->v_mount->mnt_stat.f_iosize;
 527
 528         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 529
 530         sf = sf_buf_alloc(m, 0);
 531
 532         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 533                 vm_ooffset_t address;
 534
 535                 bits = vm_page_bits(i * bsize, bsize);
 536                 if (m->valid & bits)
 537                         continue;
 538
 539                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 540                 if (address >= object->un_pager.vnp.vnp_size) {
 541                         fileaddr = -1;
 542                 } else {
 543                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 544                         if (error)
 545                                 break;
 546                 }
 547                 if (fileaddr != -1) {
 548                         bp = getpbuf(&vnode_pbuf_freecnt);
 549
 550                         /* build a minimal buffer header */
 551                         bp->b_iocmd = BIO_READ;
 552                         bp->b_iodone = bdone;
 553                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 554                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 555                         bp->b_rcred = crhold(curthread->td_ucred);
 556                         bp->b_wcred = crhold(curthread->td_ucred);
 557                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 558                         bp->b_blkno = fileaddr;
 559                         pbgetbo(bo, bp);
 560                         bp->b_vp = vp;
 561                         bp->b_bcount = bsize;
 562                         bp->b_bufsize = bsize;
 563                         bp->b_runningbufspace = bp->b_bufsize;
 564                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 565
 566                         /* do the input */
 567                         bp->b_iooffset = dbtob(bp->b_blkno);
 568                         bstrategy(bp);
 569
 570                         bwait(bp, PVM, "vnsrd");
 571
 572                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 573                                 error = EIO;
 574
 575                         /*
 576                          * free the buffer header back to the swap buffer pool
 577                          */
 578                         bp->b_vp = NULL;
 579                         pbrelbo(bp);
 580                         relpbuf(bp, &vnode_pbuf_freecnt);
 581                         if (error)
 582                                 break;
 583                 } else
 584                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 585                 KASSERT((m->dirty & bits) == 0,
 586                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 587                 VM_OBJECT_WLOCK(object);
 588                 m->valid |= bits;
 589                 VM_OBJECT_WUNLOCK(object);
 590         }
 591         sf_buf_free(sf);
 592         if (error) {
 593                 return VM_PAGER_ERROR;
 594         }
 595         return VM_PAGER_OK;
 596 }
 597
 598 /*
 599  * old style vnode pager input routine
 600  */
 601 static int
 602 vnode_pager_input_old(vm_object_t object, vm_page_t m)
 603 {
 604         struct uio auio;
 605         struct iovec aiov;
 606         int error;
 607         int size;
 608         struct sf_buf *sf;
 609         struct vnode *vp;
 610
 611         VM_OBJECT_ASSERT_WLOCKED(object);
 612         error = 0;
 613
 614         /*
 615          * Return failure if beyond current EOF
 616          */
 617         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 618                 return VM_PAGER_BAD;
 619         } else {
 620                 size = PAGE_SIZE;
 621                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 622                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 623                 vp = object->handle;
 624                 VM_OBJECT_WUNLOCK(object);
 625
 626                 /*
 627                  * Allocate a kernel virtual address and initialize so that
 628                  * we can use VOP_READ/WRITE routines.
 629                  */
 630                 sf = sf_buf_alloc(m, 0);
 631
 632                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 633                 aiov.iov_len = size;
 634                 auio.uio_iov = &aiov;
 635                 auio.uio_iovcnt = 1;
 636                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 637                 auio.uio_segflg = UIO_SYSSPACE;
 638                 auio.uio_rw = UIO_READ;
 639                 auio.uio_resid = size;
 640                 auio.uio_td = curthread;
 641
 642                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 643                 if (!error) {
 644                         int count = size - auio.uio_resid;
 645
 646                         if (count == 0)
 647                                 error = EINVAL;
 648                         else if (count != PAGE_SIZE)
 649                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 650                                     PAGE_SIZE - count);
 651                 }
 652                 sf_buf_free(sf);
 653
 654                 VM_OBJECT_WLOCK(object);
 655         }
 656         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 657         if (!error)
 658                 m->valid = VM_PAGE_BITS_ALL;
 659         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 660 }
 661
 662 /*
 663  * generic vnode pager input routine
 664  */
 665
 666 /*
 667  * Local media VFS's that do not implement their own VOP_GETPAGES
 668  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 669  * to implement the previous behaviour.
 670  *
 671  * All other FS's should use the bypass to get to the local media
 672  * backing vp's VOP_GETPAGES.
 673  */
 674 static int
 675 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
 676     int *rahead)
 677 {
 678         struct vnode *vp;
 679         int rtval;
 680
 681         vp = object->handle;
 682         VM_OBJECT_WUNLOCK(object);
 683         rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
 684         KASSERT(rtval != EOPNOTSUPP,
 685             ("vnode_pager: FS getpages not implemented\n"));
 686         VM_OBJECT_WLOCK(object);
 687         return rtval;
 688 }
 689
 690 static int
 691 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
 692     int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
 693 {
 694         struct vnode *vp;
 695         int rtval;
 696
 697         vp = object->handle;
 698         VM_OBJECT_WUNLOCK(object);
 699         rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
 700         KASSERT(rtval != EOPNOTSUPP,
 701             ("vnode_pager: FS getpages_async not implemented\n"));
 702         VM_OBJECT_WLOCK(object);
 703         return (rtval);
 704 }
 705
 706 /*
 707  * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
 708  * local filesystems, where partially valid pages can only occur at
 709  * the end of file.
 710  */
 711 int
 712 vnode_pager_local_getpages(struct vop_getpages_args *ap)
 713 {
 714
 715         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 716             ap->a_rbehind, ap->a_rahead, NULL, NULL));
 717 }
 718
 719 int
 720 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
 721 {
 722
 723         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 724             ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg));
 725 }
 726
 727 /*
 728  * This is now called from local media FS's to operate against their
 729  * own vnodes if they fail to implement VOP_GETPAGES.
 730  */
 731 int
 732 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
 733     int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
 734 {
 735         vm_object_t object;
 736         struct bufobj *bo;
 737         struct buf *bp;
 738         off_t foff;
 739         int bsize, pagesperblock, *freecnt;
 740         int error, before, after, rbehind, rahead, poff, i;
 741         int bytecount, secmask;
 742
 743         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 744             ("%s does not support devices", __func__));
 745
 746         if (vp->v_iflag & VI_DOOMED)
 747                 return (VM_PAGER_BAD);
 748
 749         object = vp->v_object;
 750         foff = IDX_TO_OFF(m[0]->pindex);
 751         bsize = vp->v_mount->mnt_stat.f_iosize;
 752         pagesperblock = bsize / PAGE_SIZE;
 753
 754         KASSERT(foff < object->un_pager.vnp.vnp_size,
 755             ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
 756         KASSERT(count <= sizeof(bp->b_pages),
 757             ("%s: requested %d pages", __func__, count));
 758
 759         /*
 760          * The last page has valid blocks.  Invalid part can only
 761          * exist at the end of file, and the page is made fully valid
 762          * by zeroing in vm_pager_get_pages().
 763          */
 764         if (m[count - 1]->valid != 0 && --count == 0) {
 765                 if (iodone != NULL)
 766                         iodone(arg, m, 1, 0);
 767                 return (VM_PAGER_OK);
 768         }
 769
 770         /*
 771          * Synchronous and asynchronous paging operations use different
 772          * free pbuf counters.  This is done to avoid asynchronous requests
 773          * to consume all pbufs.
 774          * Allocate the pbuf at the very beginning of the function, so that
 775          * if we are low on certain kind of pbufs don't even proceed to BMAP,
 776          * but sleep.
 777          */
 778         freecnt = iodone != NULL ?
 779             &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
 780         bp = getpbuf(freecnt);
 781
 782         /*
 783          * Get the underlying device blocks for the file with VOP_BMAP().
 784          * If the file system doesn't support VOP_BMAP, use old way of
 785          * getting pages via VOP_READ.
 786          */
 787         error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
 788         if (error == EOPNOTSUPP) {
 789                 relpbuf(bp, freecnt);
 790                 VM_OBJECT_WLOCK(object);
 791                 for (i = 0; i < count; i++) {
 792                         PCPU_INC(cnt.v_vnodein);
 793                         PCPU_INC(cnt.v_vnodepgsin);
 794                         error = vnode_pager_input_old(object, m[i]);
 795                         if (error)
 796                                 break;
 797                 }
 798                 VM_OBJECT_WUNLOCK(object);
 799                 return (error);
 800         } else if (error != 0) {
 801                 relpbuf(bp, freecnt);
 802                 return (VM_PAGER_ERROR);
 803         }
 804
 805         /*
 806          * If the file system supports BMAP, but blocksize is smaller
 807          * than a page size, then use special small filesystem code.
 808          */
 809         if (pagesperblock == 0) {
 810                 relpbuf(bp, freecnt);
 811                 for (i = 0; i < count; i++) {
 812                         PCPU_INC(cnt.v_vnodein);
 813                         PCPU_INC(cnt.v_vnodepgsin);
 814                         error = vnode_pager_input_smlfs(object, m[i]);
 815                         if (error)
 816                                 break;
 817                 }
 818                 return (error);
 819         }
 820
 821         /*
 822          * A sparse file can be encountered only for a single page request,
 823          * which may not be preceded by call to vm_pager_haspage().
 824          */
 825         if (bp->b_blkno == -1) {
 826                 KASSERT(count == 1,
 827                     ("%s: array[%d] request to a sparse file %p", __func__,
 828                     count, vp));
 829                 relpbuf(bp, freecnt);
 830                 pmap_zero_page(m[0]);
 831                 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
 832                     __func__, m[0]));
 833                 VM_OBJECT_WLOCK(object);
 834                 m[0]->valid = VM_PAGE_BITS_ALL;
 835                 VM_OBJECT_WUNLOCK(object);
 836                 return (VM_PAGER_OK);
 837         }
 838
 839         bp->b_blkno += (foff % bsize) / DEV_BSIZE;
 840
 841         /* Recalculate blocks available after/before to pages. */
 842         poff = (foff % bsize) / PAGE_SIZE;
 843         before *= pagesperblock;
 844         before += poff;
 845         after *= pagesperblock;
 846         after += pagesperblock - (poff + 1);
 847         if (m[0]->pindex + after >= object->size)
 848                 after = object->size - 1 - m[0]->pindex;
 849         KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
 850             __func__, count, after + 1));
 851         after -= count - 1;
 852
 853         /* Trim requested rbehind/rahead to possible values. */
 854         rbehind = a_rbehind ? *a_rbehind : 0;
 855         rahead = a_rahead ? *a_rahead : 0;
 856         rbehind = min(rbehind, before);
 857         rbehind = min(rbehind, m[0]->pindex);
 858         rahead = min(rahead, after);
 859         rahead = min(rahead, object->size - m[count - 1]->pindex);
 860         KASSERT(rbehind + rahead + count <= sizeof(bp->b_pages),
 861             ("%s: behind %d ahead %d count %d", __func__,
 862             rbehind, rahead, count));
 863
 864         /*
 865          * Fill in the bp->b_pages[] array with requested and optional
 866          * read behind or read ahead pages.  Read behind pages are looked
 867          * up in a backward direction, down to a first cached page.  Same
 868          * for read ahead pages, but there is no need to shift the array
 869          * in case of encountering a cached page.
 870          */
 871         i = bp->b_npages = 0;
 872         if (rbehind) {
 873                 vm_pindex_t startpindex, tpindex;
 874                 vm_page_t p;
 875
 876                 VM_OBJECT_WLOCK(object);
 877                 startpindex = m[0]->pindex - rbehind;
 878                 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
 879                     p->pindex >= startpindex)
 880                         startpindex = p->pindex + 1;
 881
 882                 /* tpindex is unsigned; beware of numeric underflow. */
 883                 for (tpindex = m[0]->pindex - 1;
 884                     tpindex >= startpindex && tpindex < m[0]->pindex;
 885                     tpindex--, i++) {
 886                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 887                             VM_ALLOC_IFNOTCACHED);
 888                         if (p == NULL) {
 889                                 /* Shift the array. */
 890                                 for (int j = 0; j < i; j++)
 891                                         bp->b_pages[j] = bp->b_pages[j +
 892                                             tpindex + 1 - startpindex];
 893                                 break;
 894                         }
 895                         bp->b_pages[tpindex - startpindex] = p;
 896                 }
 897
 898                 bp->b_pgbefore = i;
 899                 bp->b_npages += i;
 900                 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
 901         } else
 902                 bp->b_pgbefore = 0;
 903
 904         /* Requested pages. */
 905         for (int j = 0; j < count; j++, i++)
 906                 bp->b_pages[i] = m[j];
 907         bp->b_npages += count;
 908
 909         if (rahead) {
 910                 vm_pindex_t endpindex, tpindex;
 911                 vm_page_t p;
 912
 913                 if (!VM_OBJECT_WOWNED(object))
 914                         VM_OBJECT_WLOCK(object);
 915                 endpindex = m[count - 1]->pindex + rahead + 1;
 916                 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
 917                     p->pindex < endpindex)
 918                         endpindex = p->pindex;
 919                 if (endpindex > object->size)
 920                         endpindex = object->size;
 921
 922                 for (tpindex = m[count - 1]->pindex + 1;
 923                     tpindex < endpindex; i++, tpindex++) {
 924                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 925                             VM_ALLOC_IFNOTCACHED);
 926                         if (p == NULL)
 927                                 break;
 928                         bp->b_pages[i] = p;
 929                 }
 930
 931                 bp->b_pgafter = i - bp->b_npages;
 932                 bp->b_npages = i;
 933         } else
 934                 bp->b_pgafter = 0;
 935
 936         if (VM_OBJECT_WOWNED(object))
 937                 VM_OBJECT_WUNLOCK(object);
 938
 939         /* Report back actual behind/ahead read. */
 940         if (a_rbehind)
 941                 *a_rbehind = bp->b_pgbefore;
 942         if (a_rahead)
 943                 *a_rahead = bp->b_pgafter;
 944
 945         KASSERT(bp->b_npages <= sizeof(bp->b_pages),
 946             ("%s: buf %p overflowed", __func__, bp));
 947
 948         /*
 949          * Recalculate first offset and bytecount with regards to read behind.
 950          * Truncate bytecount to vnode real size and round up physical size
 951          * for real devices.
 952          */
 953         foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
 954         bytecount = bp->b_npages << PAGE_SHIFT;
 955         if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
 956                 bytecount = object->un_pager.vnp.vnp_size - foff;
 957         secmask = bo->bo_bsize - 1;
 958         KASSERT(secmask < PAGE_SIZE && secmask > 0,
 959             ("%s: sector size %d too large", __func__, secmask + 1));
 960         bytecount = (bytecount + secmask) & ~secmask;
 961
 962         /*
 963          * And map the pages to be read into the kva, if the filesystem
 964          * requires mapped buffers.
 965          */
 966         if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
 967             unmapped_buf_allowed) {
 968                 bp->b_data = unmapped_buf;
 969                 bp->b_offset = 0;
 970         } else {
 971                 bp->b_data = bp->b_kvabase;
 972                 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
 973         }
 974
 975         /* Build a minimal buffer header. */
 976         bp->b_iocmd = BIO_READ;
 977         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 978         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 979         bp->b_rcred = crhold(curthread->td_ucred);
 980         bp->b_wcred = crhold(curthread->td_ucred);
 981         pbgetbo(bo, bp);
 982         bp->b_vp = vp;
 983         bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
 984         bp->b_iooffset = dbtob(bp->b_blkno);
 985
 986         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 987         PCPU_INC(cnt.v_vnodein);
 988         PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages);
 989
 990         if (iodone != NULL) { /* async */
 991                 bp->b_pgiodone = iodone;
 992                 bp->b_caller1 = arg;
 993                 bp->b_iodone = vnode_pager_generic_getpages_done_async;
 994                 bp->b_flags |= B_ASYNC;
 995                 BUF_KERNPROC(bp);
 996                 bstrategy(bp);
 997                 return (VM_PAGER_OK);
 998         } else {
 999                 bp->b_iodone = bdone;
1000                 bstrategy(bp);
1001                 bwait(bp, PVM, "vnread");
1002                 error = vnode_pager_generic_getpages_done(bp);
1003                 for (i = 0; i < bp->b_npages; i++)
1004                         bp->b_pages[i] = NULL;
1005                 bp->b_vp = NULL;
1006                 pbrelbo(bp);
1007                 relpbuf(bp, &vnode_pbuf_freecnt);
1008                 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
1009         }
1010 }
1011
1012 static void
1013 vnode_pager_generic_getpages_done_async(struct buf *bp)
1014 {
1015         int error;
1016
1017         error = vnode_pager_generic_getpages_done(bp);
1018         /* Run the iodone upon the requested range. */
1019         bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
1020             bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
1021         for (int i = 0; i < bp->b_npages; i++)
1022                 bp->b_pages[i] = NULL;
1023         bp->b_vp = NULL;
1024         pbrelbo(bp);
1025         relpbuf(bp, &vnode_async_pbuf_freecnt);
1026 }
1027
1028 static int
1029 vnode_pager_generic_getpages_done(struct buf *bp)
1030 {
1031         vm_object_t object;
1032         off_t tfoff, nextoff;
1033         int i, error;
1034
1035         error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0;
1036         object = bp->b_vp->v_object;
1037
1038         if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
1039                 if (!buf_mapped(bp)) {
1040                         bp->b_data = bp->b_kvabase;
1041                         pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
1042                             bp->b_npages);
1043                 }
1044                 bzero(bp->b_data + bp->b_bcount,
1045                     PAGE_SIZE * bp->b_npages - bp->b_bcount);
1046         }
1047         if (buf_mapped(bp)) {
1048                 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1049                 bp->b_data = unmapped_buf;
1050         }
1051
1052         VM_OBJECT_WLOCK(object);
1053         for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1054             i < bp->b_npages; i++, tfoff = nextoff) {
1055                 vm_page_t mt;
1056
1057                 nextoff = tfoff + PAGE_SIZE;
1058                 mt = bp->b_pages[i];
1059
1060                 if (nextoff <= object->un_pager.vnp.vnp_size) {
1061                         /*
1062                          * Read filled up entire page.
1063                          */
1064                         mt->valid = VM_PAGE_BITS_ALL;
1065                         KASSERT(mt->dirty == 0,
1066                             ("%s: page %p is dirty", __func__, mt));
1067                         KASSERT(!pmap_page_is_mapped(mt),
1068                             ("%s: page %p is mapped", __func__, mt));
1069                 } else {
1070                         /*
1071                          * Read did not fill up entire page.
1072                          *
1073                          * Currently we do not set the entire page valid,
1074                          * we just try to clear the piece that we couldn't
1075                          * read.
1076                          */
1077                         vm_page_set_valid_range(mt, 0,
1078                             object->un_pager.vnp.vnp_size - tfoff);
1079                         KASSERT((mt->dirty & vm_page_bits(0,
1080                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
1081                             ("%s: page %p is dirty", __func__, mt));
1082                 }
1083
1084                 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
1085                         vm_page_readahead_finish(mt);
1086         }
1087         VM_OBJECT_WUNLOCK(object);
1088         if (error != 0)
1089                 printf("%s: I/O read error %d\n", __func__, error);
1090
1091         return (error);
1092 }
1093
1094 /*
1095  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1096  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1097  * vnode_pager_generic_putpages() to implement the previous behaviour.
1098  *
1099  * All other FS's should use the bypass to get to the local media
1100  * backing vp's VOP_PUTPAGES.
1101  */
1102 static void
1103 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1104     int flags, int *rtvals)
1105 {
1106         int rtval;
1107         struct vnode *vp;
1108         int bytes = count * PAGE_SIZE;
1109
1110         /*
1111          * Force synchronous operation if we are extremely low on memory
1112          * to prevent a low-memory deadlock.  VOP operations often need to
1113          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1114          * operation ).  The swapper handles the case by limiting the amount
1115          * of asynchronous I/O, but that sort of solution doesn't scale well
1116          * for the vnode pager without a lot of work.
1117          *
1118          * Also, the backing vnode's iodone routine may not wake the pageout
1119          * daemon up.  This should be probably be addressed XXX.
1120          */
1121
1122         if (vm_cnt.v_free_count + vm_cnt.v_cache_count <
1123             vm_cnt.v_pageout_free_min)
1124                 flags |= VM_PAGER_PUT_SYNC;
1125
1126         /*
1127          * Call device-specific putpages function
1128          */
1129         vp = object->handle;
1130         VM_OBJECT_WUNLOCK(object);
1131         rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
1132         KASSERT(rtval != EOPNOTSUPP,
1133             ("vnode_pager: stale FS putpages\n"));
1134         VM_OBJECT_WLOCK(object);
1135 }
1136
1137
1138 /*
1139  * This is now called from local media FS's to operate against their
1140  * own vnodes if they fail to implement VOP_PUTPAGES.
1141  *
1142  * This is typically called indirectly via the pageout daemon and
1143  * clustering has already typically occurred, so in general we ask the
1144  * underlying filesystem to write the data out asynchronously rather
1145  * then delayed.
1146  */
1147 int
1148 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1149     int flags, int *rtvals)
1150 {
1151         int i;
1152         vm_object_t object;
1153         vm_page_t m;
1154         int count;
1155
1156         int maxsize, ncount;
1157         vm_ooffset_t poffset;
1158         struct uio auio;
1159         struct iovec aiov;
1160         int error;
1161         int ioflags;
1162         int ppscheck = 0;
1163         static struct timeval lastfail;
1164         static int curfail;
1165
1166         object = vp->v_object;
1167         count = bytecount / PAGE_SIZE;
1168
1169         for (i = 0; i < count; i++)
1170                 rtvals[i] = VM_PAGER_ERROR;
1171
1172         if ((int64_t)ma[0]->pindex < 0) {
1173                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1174                     (long)ma[0]->pindex, (u_long)ma[0]->dirty);
1175                 rtvals[0] = VM_PAGER_BAD;
1176                 return VM_PAGER_BAD;
1177         }
1178
1179         maxsize = count * PAGE_SIZE;
1180         ncount = count;
1181
1182         poffset = IDX_TO_OFF(ma[0]->pindex);
1183
1184         /*
1185          * If the page-aligned write is larger then the actual file we
1186          * have to invalidate pages occurring beyond the file EOF.  However,
1187          * there is an edge case where a file may not be page-aligned where
1188          * the last page is partially invalid.  In this case the filesystem
1189          * may not properly clear the dirty bits for the entire page (which
1190          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1191          * With the page locked we are free to fix-up the dirty bits here.
1192          *
1193          * We do not under any circumstances truncate the valid bits, as
1194          * this will screw up bogus page replacement.
1195          */
1196         VM_OBJECT_WLOCK(object);
1197         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1198                 if (object->un_pager.vnp.vnp_size > poffset) {
1199                         int pgoff;
1200
1201                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1202                         ncount = btoc(maxsize);
1203                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1204                                 /*
1205                                  * If the object is locked and the following
1206                                  * conditions hold, then the page's dirty
1207                                  * field cannot be concurrently changed by a
1208                                  * pmap operation.
1209                                  */
1210                                 m = ma[ncount - 1];
1211                                 vm_page_assert_sbusied(m);
1212                                 KASSERT(!pmap_page_is_write_mapped(m),
1213                 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1214                                 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1215                                     pgoff);
1216                         }
1217                 } else {
1218                         maxsize = 0;
1219                         ncount = 0;
1220                 }
1221                 if (ncount < count) {
1222                         for (i = ncount; i < count; i++) {
1223                                 rtvals[i] = VM_PAGER_BAD;
1224                         }
1225                 }
1226         }
1227         VM_OBJECT_WUNLOCK(object);
1228
1229         /*
1230          * pageouts are already clustered, use IO_ASYNC to force a bawrite()
1231          * rather then a bdwrite() to prevent paging I/O from saturating
1232          * the buffer cache.  Dummy-up the sequential heuristic to cause
1233          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
1234          * the system decides how to cluster.
1235          */
1236         ioflags = IO_VMIO;
1237         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1238                 ioflags |= IO_SYNC;
1239         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1240                 ioflags |= IO_ASYNC;
1241         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1242         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1243
1244         aiov.iov_base = (caddr_t) 0;
1245         aiov.iov_len = maxsize;
1246         auio.uio_iov = &aiov;
1247         auio.uio_iovcnt = 1;
1248         auio.uio_offset = poffset;
1249         auio.uio_segflg = UIO_NOCOPY;
1250         auio.uio_rw = UIO_WRITE;
1251         auio.uio_resid = maxsize;
1252         auio.uio_td = (struct thread *) 0;
1253         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1254         PCPU_INC(cnt.v_vnodeout);
1255         PCPU_ADD(cnt.v_vnodepgsout, ncount);
1256
1257         if (error) {
1258                 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1259                         printf("vnode_pager_putpages: I/O error %d\n", error);
1260         }
1261         if (auio.uio_resid) {
1262                 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1263                         printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1264                             auio.uio_resid, (u_long)ma[0]->pindex);
1265         }
1266         for (i = 0; i < ncount; i++) {
1267                 rtvals[i] = VM_PAGER_OK;
1268         }
1269         return rtvals[0];
1270 }
1271
1272 void
1273 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written)
1274 {
1275         vm_object_t obj;
1276         int i, pos;
1277
1278         if (written == 0)
1279                 return;
1280         obj = ma[0]->object;
1281         VM_OBJECT_WLOCK(obj);
1282         for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1283                 if (pos < trunc_page(written)) {
1284                         rtvals[i] = VM_PAGER_OK;
1285                         vm_page_undirty(ma[i]);
1286                 } else {
1287                         /* Partially written page. */
1288                         rtvals[i] = VM_PAGER_AGAIN;
1289                         vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1290                 }
1291         }
1292         VM_OBJECT_WUNLOCK(obj);
1293 }
1294
1295 void
1296 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1297     vm_offset_t end)
1298 {
1299         struct vnode *vp;
1300         vm_ooffset_t old_wm;
1301
1302         VM_OBJECT_WLOCK(object);
1303         if (object->type != OBJT_VNODE) {
1304                 VM_OBJECT_WUNLOCK(object);
1305                 return;
1306         }
1307         old_wm = object->un_pager.vnp.writemappings;
1308         object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1309         vp = object->handle;
1310         if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1311                 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1312                 VOP_ADD_WRITECOUNT(vp, 1);
1313                 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1314                     __func__, vp, vp->v_writecount);
1315         } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1316                 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1317                 VOP_ADD_WRITECOUNT(vp, -1);
1318                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1319                     __func__, vp, vp->v_writecount);
1320         }
1321         VM_OBJECT_WUNLOCK(object);
1322 }
1323
1324 void
1325 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1326     vm_offset_t end)
1327 {
1328         struct vnode *vp;
1329         struct mount *mp;
1330         vm_offset_t inc;
1331
1332         VM_OBJECT_WLOCK(object);
1333
1334         /*
1335          * First, recheck the object type to account for the race when
1336          * the vnode is reclaimed.
1337          */
1338         if (object->type != OBJT_VNODE) {
1339                 VM_OBJECT_WUNLOCK(object);
1340                 return;
1341         }
1342
1343         /*
1344          * Optimize for the case when writemappings is not going to
1345          * zero.
1346          */
1347         inc = end - start;
1348         if (object->un_pager.vnp.writemappings != inc) {
1349                 object->un_pager.vnp.writemappings -= inc;
1350                 VM_OBJECT_WUNLOCK(object);
1351                 return;
1352         }
1353
1354         vp = object->handle;
1355         vhold(vp);
1356         VM_OBJECT_WUNLOCK(object);
1357         mp = NULL;
1358         vn_start_write(vp, &mp, V_WAIT);
1359         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1360
1361         /*
1362          * Decrement the object's writemappings, by swapping the start
1363          * and end arguments for vnode_pager_update_writecount().  If
1364          * there was not a race with vnode reclaimation, then the
1365          * vnode's v_writecount is decremented.
1366          */
1367         vnode_pager_update_writecount(object, end, start);
1368         VOP_UNLOCK(vp, 0);
1369         vdrop(vp);
1370         if (mp != NULL)
1371                 vn_finished_write(mp);
1372 }