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                         /*
 176                          * Waiters were already handled during object
 177                          * termination.  The exclusive vnode lock hopefully
 178                          * prevented new waiters from referencing the dying
 179                          * object.
 180                          */
 181                         KASSERT((obj->flags & OBJ_DISCONNECTWNT) == 0,
 182                             ("OBJ_DISCONNECTWNT set obj %p flags %x",
 183                             obj, obj->flags));
 184                         vp->v_object = NULL;
 185                         VM_OBJECT_WUNLOCK(obj);
 186                 }
 187         } else {
 188                 /*
 189                  * Woe to the process that tries to page now :-).
 190                  */
 191                 vm_pager_deallocate(obj);
 192                 VM_OBJECT_WUNLOCK(obj);
 193         }
 194         KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object));
 195 }
 196
 197
 198 /*
 199  * Allocate (or lookup) pager for a vnode.
 200  * Handle is a vnode pointer.
 201  *
 202  * MPSAFE
 203  */
 204 vm_object_t
 205 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 206     vm_ooffset_t offset, struct ucred *cred)
 207 {
 208         vm_object_t object;
 209         struct vnode *vp;
 210
 211         /*
 212          * Pageout to vnode, no can do yet.
 213          */
 214         if (handle == NULL)
 215                 return (NULL);
 216
 217         vp = (struct vnode *) handle;
 218
 219         /*
 220          * If the object is being terminated, wait for it to
 221          * go away.
 222          */
 223 retry:
 224         while ((object = vp->v_object) != NULL) {
 225                 VM_OBJECT_WLOCK(object);
 226                 if ((object->flags & OBJ_DEAD) == 0)
 227                         break;
 228                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 229                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
 230         }
 231
 232         KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
 233
 234         if (object == NULL) {
 235                 /*
 236                  * Add an object of the appropriate size
 237                  */
 238                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 239
 240                 object->un_pager.vnp.vnp_size = size;
 241                 object->un_pager.vnp.writemappings = 0;
 242
 243                 object->handle = handle;
 244                 VI_LOCK(vp);
 245                 if (vp->v_object != NULL) {
 246                         /*
 247                          * Object has been created while we were sleeping
 248                          */
 249                         VI_UNLOCK(vp);
 250                         VM_OBJECT_WLOCK(object);
 251                         KASSERT(object->ref_count == 1,
 252                             ("leaked ref %p %d", object, object->ref_count));
 253                         object->type = OBJT_DEAD;
 254                         object->ref_count = 0;
 255                         VM_OBJECT_WUNLOCK(object);
 256                         vm_object_destroy(object);
 257                         goto retry;
 258                 }
 259                 vp->v_object = object;
 260                 VI_UNLOCK(vp);
 261         } else {
 262                 object->ref_count++;
 263 #if VM_NRESERVLEVEL > 0
 264                 vm_object_color(object, 0);
 265 #endif
 266                 VM_OBJECT_WUNLOCK(object);
 267         }
 268         vref(vp);
 269         return (object);
 270 }
 271
 272 /*
 273  *      The object must be locked.
 274  */
 275 static void
 276 vnode_pager_dealloc(vm_object_t object)
 277 {
 278         struct vnode *vp;
 279         int refs;
 280
 281         vp = object->handle;
 282         if (vp == NULL)
 283                 panic("vnode_pager_dealloc: pager already dealloced");
 284
 285         VM_OBJECT_ASSERT_WLOCKED(object);
 286         vm_object_pip_wait(object, "vnpdea");
 287         refs = object->ref_count;
 288
 289         object->handle = NULL;
 290         object->type = OBJT_DEAD;
 291         if (object->flags & OBJ_DISCONNECTWNT) {
 292                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 293                 wakeup(object);
 294         }
 295         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 296         if (object->un_pager.vnp.writemappings > 0) {
 297                 object->un_pager.vnp.writemappings = 0;
 298                 VOP_ADD_WRITECOUNT(vp, -1);
 299                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
 300                     __func__, vp, vp->v_writecount);
 301         }
 302         vp->v_object = NULL;
 303         VOP_UNSET_TEXT(vp);
 304         VM_OBJECT_WUNLOCK(object);
 305         while (refs-- > 0)
 306                 vunref(vp);
 307         VM_OBJECT_WLOCK(object);
 308 }
 309
 310 static boolean_t
 311 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 312     int *after)
 313 {
 314         struct vnode *vp = object->handle;
 315         daddr_t bn;
 316         int err;
 317         daddr_t reqblock;
 318         int poff;
 319         int bsize;
 320         int pagesperblock, blocksperpage;
 321
 322         VM_OBJECT_ASSERT_WLOCKED(object);
 323         /*
 324          * If no vp or vp is doomed or marked transparent to VM, we do not
 325          * have the page.
 326          */
 327         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 328                 return FALSE;
 329         /*
 330          * If the offset is beyond end of file we do
 331          * not have the page.
 332          */
 333         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 334                 return FALSE;
 335
 336         bsize = vp->v_mount->mnt_stat.f_iosize;
 337         pagesperblock = bsize / PAGE_SIZE;
 338         blocksperpage = 0;
 339         if (pagesperblock > 0) {
 340                 reqblock = pindex / pagesperblock;
 341         } else {
 342                 blocksperpage = (PAGE_SIZE / bsize);
 343                 reqblock = pindex * blocksperpage;
 344         }
 345         VM_OBJECT_WUNLOCK(object);
 346         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 347         VM_OBJECT_WLOCK(object);
 348         if (err)
 349                 return TRUE;
 350         if (bn == -1)
 351                 return FALSE;
 352         if (pagesperblock > 0) {
 353                 poff = pindex - (reqblock * pagesperblock);
 354                 if (before) {
 355                         *before *= pagesperblock;
 356                         *before += poff;
 357                 }
 358                 if (after) {
 359                         /*
 360                          * The BMAP vop can report a partial block in the
 361                          * 'after', but must not report blocks after EOF.
 362                          * Assert the latter, and truncate 'after' in case
 363                          * of the former.
 364                          */
 365                         KASSERT((reqblock + *after) * pagesperblock <
 366                             roundup2(object->size, pagesperblock),
 367                             ("%s: reqblock %jd after %d size %ju", __func__,
 368                             (intmax_t )reqblock, *after,
 369                             (uintmax_t )object->size));
 370                         *after *= pagesperblock;
 371                         *after += pagesperblock - (poff + 1);
 372                         if (pindex + *after >= object->size)
 373                                 *after = object->size - 1 - pindex;
 374                 }
 375         } else {
 376                 if (before) {
 377                         *before /= blocksperpage;
 378                 }
 379
 380                 if (after) {
 381                         *after /= blocksperpage;
 382                 }
 383         }
 384         return TRUE;
 385 }
 386
 387 /*
 388  * Lets the VM system know about a change in size for a file.
 389  * We adjust our own internal size and flush any cached pages in
 390  * the associated object that are affected by the size change.
 391  *
 392  * Note: this routine may be invoked as a result of a pager put
 393  * operation (possibly at object termination time), so we must be careful.
 394  */
 395 void
 396 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
 397 {
 398         vm_object_t object;
 399         vm_page_t m;
 400         vm_pindex_t nobjsize;
 401
 402         if ((object = vp->v_object) == NULL)
 403                 return;
 404 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 405         VM_OBJECT_WLOCK(object);
 406         if (object->type == OBJT_DEAD) {
 407                 VM_OBJECT_WUNLOCK(object);
 408                 return;
 409         }
 410         KASSERT(object->type == OBJT_VNODE,
 411             ("not vnode-backed object %p", object));
 412         if (nsize == object->un_pager.vnp.vnp_size) {
 413                 /*
 414                  * Hasn't changed size
 415                  */
 416                 VM_OBJECT_WUNLOCK(object);
 417                 return;
 418         }
 419         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 420         if (nsize < object->un_pager.vnp.vnp_size) {
 421                 /*
 422                  * File has shrunk. Toss any cached pages beyond the new EOF.
 423                  */
 424                 if (nobjsize < object->size)
 425                         vm_object_page_remove(object, nobjsize, object->size,
 426                             0);
 427                 /*
 428                  * this gets rid of garbage at the end of a page that is now
 429                  * only partially backed by the vnode.
 430                  *
 431                  * XXX for some reason (I don't know yet), if we take a
 432                  * completely invalid page and mark it partially valid
 433                  * it can screw up NFS reads, so we don't allow the case.
 434                  */
 435                 if ((nsize & PAGE_MASK) &&
 436                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 437                     m->valid != 0) {
 438                         int base = (int)nsize & PAGE_MASK;
 439                         int size = PAGE_SIZE - base;
 440
 441                         /*
 442                          * Clear out partial-page garbage in case
 443                          * the page has been mapped.
 444                          */
 445                         pmap_zero_page_area(m, base, size);
 446
 447                         /*
 448                          * Update the valid bits to reflect the blocks that
 449                          * have been zeroed.  Some of these valid bits may
 450                          * have already been set.
 451                          */
 452                         vm_page_set_valid_range(m, base, size);
 453
 454                         /*
 455                          * Round "base" to the next block boundary so that the
 456                          * dirty bit for a partially zeroed block is not
 457                          * cleared.
 458                          */
 459                         base = roundup2(base, DEV_BSIZE);
 460
 461                         /*
 462                          * Clear out partial-page dirty bits.
 463                          *
 464                          * note that we do not clear out the valid
 465                          * bits.  This would prevent bogus_page
 466                          * replacement from working properly.
 467                          */
 468                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 469                 } else if ((nsize & PAGE_MASK) &&
 470                     vm_page_is_cached(object, OFF_TO_IDX(nsize))) {
 471                         vm_page_cache_free(object, OFF_TO_IDX(nsize),
 472                             nobjsize);
 473                 }
 474         }
 475         object->un_pager.vnp.vnp_size = nsize;
 476         object->size = nobjsize;
 477         VM_OBJECT_WUNLOCK(object);
 478 }
 479
 480 /*
 481  * calculate the linear (byte) disk address of specified virtual
 482  * file address
 483  */
 484 static int
 485 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 486     int *run)
 487 {
 488         int bsize;
 489         int err;
 490         daddr_t vblock;
 491         daddr_t voffset;
 492
 493         if (address < 0)
 494                 return -1;
 495
 496         if (vp->v_iflag & VI_DOOMED)
 497                 return -1;
 498
 499         bsize = vp->v_mount->mnt_stat.f_iosize;
 500         vblock = address / bsize;
 501         voffset = address % bsize;
 502
 503         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 504         if (err == 0) {
 505                 if (*rtaddress != -1)
 506                         *rtaddress += voffset / DEV_BSIZE;
 507                 if (run) {
 508                         *run += 1;
 509                         *run *= bsize/PAGE_SIZE;
 510                         *run -= voffset/PAGE_SIZE;
 511                 }
 512         }
 513
 514         return (err);
 515 }
 516
 517 /*
 518  * small block filesystem vnode pager input
 519  */
 520 static int
 521 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
 522 {
 523         struct vnode *vp;
 524         struct bufobj *bo;
 525         struct buf *bp;
 526         struct sf_buf *sf;
 527         daddr_t fileaddr;
 528         vm_offset_t bsize;
 529         vm_page_bits_t bits;
 530         int error, i;
 531
 532         error = 0;
 533         vp = object->handle;
 534         if (vp->v_iflag & VI_DOOMED)
 535                 return VM_PAGER_BAD;
 536
 537         bsize = vp->v_mount->mnt_stat.f_iosize;
 538
 539         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 540
 541         sf = sf_buf_alloc(m, 0);
 542
 543         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 544                 vm_ooffset_t address;
 545
 546                 bits = vm_page_bits(i * bsize, bsize);
 547                 if (m->valid & bits)
 548                         continue;
 549
 550                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 551                 if (address >= object->un_pager.vnp.vnp_size) {
 552                         fileaddr = -1;
 553                 } else {
 554                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 555                         if (error)
 556                                 break;
 557                 }
 558                 if (fileaddr != -1) {
 559                         bp = getpbuf(&vnode_pbuf_freecnt);
 560
 561                         /* build a minimal buffer header */
 562                         bp->b_iocmd = BIO_READ;
 563                         bp->b_iodone = bdone;
 564                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 565                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 566                         bp->b_rcred = crhold(curthread->td_ucred);
 567                         bp->b_wcred = crhold(curthread->td_ucred);
 568                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 569                         bp->b_blkno = fileaddr;
 570                         pbgetbo(bo, bp);
 571                         bp->b_vp = vp;
 572                         bp->b_bcount = bsize;
 573                         bp->b_bufsize = bsize;
 574                         bp->b_runningbufspace = bp->b_bufsize;
 575                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 576
 577                         /* do the input */
 578                         bp->b_iooffset = dbtob(bp->b_blkno);
 579                         bstrategy(bp);
 580
 581                         bwait(bp, PVM, "vnsrd");
 582
 583                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 584                                 error = EIO;
 585
 586                         /*
 587                          * free the buffer header back to the swap buffer pool
 588                          */
 589                         bp->b_vp = NULL;
 590                         pbrelbo(bp);
 591                         relpbuf(bp, &vnode_pbuf_freecnt);
 592                         if (error)
 593                                 break;
 594                 } else
 595                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 596                 KASSERT((m->dirty & bits) == 0,
 597                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 598                 VM_OBJECT_WLOCK(object);
 599                 m->valid |= bits;
 600                 VM_OBJECT_WUNLOCK(object);
 601         }
 602         sf_buf_free(sf);
 603         if (error) {
 604                 return VM_PAGER_ERROR;
 605         }
 606         return VM_PAGER_OK;
 607 }
 608
 609 /*
 610  * old style vnode pager input routine
 611  */
 612 static int
 613 vnode_pager_input_old(vm_object_t object, vm_page_t m)
 614 {
 615         struct uio auio;
 616         struct iovec aiov;
 617         int error;
 618         int size;
 619         struct sf_buf *sf;
 620         struct vnode *vp;
 621
 622         VM_OBJECT_ASSERT_WLOCKED(object);
 623         error = 0;
 624
 625         /*
 626          * Return failure if beyond current EOF
 627          */
 628         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 629                 return VM_PAGER_BAD;
 630         } else {
 631                 size = PAGE_SIZE;
 632                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 633                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 634                 vp = object->handle;
 635                 VM_OBJECT_WUNLOCK(object);
 636
 637                 /*
 638                  * Allocate a kernel virtual address and initialize so that
 639                  * we can use VOP_READ/WRITE routines.
 640                  */
 641                 sf = sf_buf_alloc(m, 0);
 642
 643                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 644                 aiov.iov_len = size;
 645                 auio.uio_iov = &aiov;
 646                 auio.uio_iovcnt = 1;
 647                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 648                 auio.uio_segflg = UIO_SYSSPACE;
 649                 auio.uio_rw = UIO_READ;
 650                 auio.uio_resid = size;
 651                 auio.uio_td = curthread;
 652
 653                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 654                 if (!error) {
 655                         int count = size - auio.uio_resid;
 656
 657                         if (count == 0)
 658                                 error = EINVAL;
 659                         else if (count != PAGE_SIZE)
 660                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 661                                     PAGE_SIZE - count);
 662                 }
 663                 sf_buf_free(sf);
 664
 665                 VM_OBJECT_WLOCK(object);
 666         }
 667         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 668         if (!error)
 669                 m->valid = VM_PAGE_BITS_ALL;
 670         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 671 }
 672
 673 /*
 674  * generic vnode pager input routine
 675  */
 676
 677 /*
 678  * Local media VFS's that do not implement their own VOP_GETPAGES
 679  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 680  * to implement the previous behaviour.
 681  *
 682  * All other FS's should use the bypass to get to the local media
 683  * backing vp's VOP_GETPAGES.
 684  */
 685 static int
 686 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
 687     int *rahead)
 688 {
 689         struct vnode *vp;
 690         int rtval;
 691
 692         vp = object->handle;
 693         VM_OBJECT_WUNLOCK(object);
 694         rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
 695         KASSERT(rtval != EOPNOTSUPP,
 696             ("vnode_pager: FS getpages not implemented\n"));
 697         VM_OBJECT_WLOCK(object);
 698         return rtval;
 699 }
 700
 701 static int
 702 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
 703     int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
 704 {
 705         struct vnode *vp;
 706         int rtval;
 707
 708         vp = object->handle;
 709         VM_OBJECT_WUNLOCK(object);
 710         rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
 711         KASSERT(rtval != EOPNOTSUPP,
 712             ("vnode_pager: FS getpages_async not implemented\n"));
 713         VM_OBJECT_WLOCK(object);
 714         return (rtval);
 715 }
 716
 717 /*
 718  * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
 719  * local filesystems, where partially valid pages can only occur at
 720  * the end of file.
 721  */
 722 int
 723 vnode_pager_local_getpages(struct vop_getpages_args *ap)
 724 {
 725
 726         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 727             ap->a_rbehind, ap->a_rahead, NULL, NULL));
 728 }
 729
 730 int
 731 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
 732 {
 733
 734         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 735             ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg));
 736 }
 737
 738 /*
 739  * This is now called from local media FS's to operate against their
 740  * own vnodes if they fail to implement VOP_GETPAGES.
 741  */
 742 int
 743 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
 744     int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
 745 {
 746         vm_object_t object;
 747         struct bufobj *bo;
 748         struct buf *bp;
 749         off_t foff;
 750         int bsize, pagesperblock, *freecnt;
 751         int error, before, after, rbehind, rahead, poff, i;
 752         int bytecount, secmask;
 753
 754         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 755             ("%s does not support devices", __func__));
 756
 757         if (vp->v_iflag & VI_DOOMED)
 758                 return (VM_PAGER_BAD);
 759
 760         object = vp->v_object;
 761         foff = IDX_TO_OFF(m[0]->pindex);
 762         bsize = vp->v_mount->mnt_stat.f_iosize;
 763         pagesperblock = bsize / PAGE_SIZE;
 764
 765         KASSERT(foff < object->un_pager.vnp.vnp_size,
 766             ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
 767         KASSERT(count <= sizeof(bp->b_pages),
 768             ("%s: requested %d pages", __func__, count));
 769
 770         /*
 771          * The last page has valid blocks.  Invalid part can only
 772          * exist at the end of file, and the page is made fully valid
 773          * by zeroing in vm_pager_get_pages().
 774          */
 775         if (m[count - 1]->valid != 0 && --count == 0) {
 776                 if (iodone != NULL)
 777                         iodone(arg, m, 1, 0);
 778                 return (VM_PAGER_OK);
 779         }
 780
 781         /*
 782          * Synchronous and asynchronous paging operations use different
 783          * free pbuf counters.  This is done to avoid asynchronous requests
 784          * to consume all pbufs.
 785          * Allocate the pbuf at the very beginning of the function, so that
 786          * if we are low on certain kind of pbufs don't even proceed to BMAP,
 787          * but sleep.
 788          */
 789         freecnt = iodone != NULL ?
 790             &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
 791         bp = getpbuf(freecnt);
 792
 793         /*
 794          * Get the underlying device blocks for the file with VOP_BMAP().
 795          * If the file system doesn't support VOP_BMAP, use old way of
 796          * getting pages via VOP_READ.
 797          */
 798         error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
 799         if (error == EOPNOTSUPP) {
 800                 relpbuf(bp, freecnt);
 801                 VM_OBJECT_WLOCK(object);
 802                 for (i = 0; i < count; i++) {
 803                         PCPU_INC(cnt.v_vnodein);
 804                         PCPU_INC(cnt.v_vnodepgsin);
 805                         error = vnode_pager_input_old(object, m[i]);
 806                         if (error)
 807                                 break;
 808                 }
 809                 VM_OBJECT_WUNLOCK(object);
 810                 return (error);
 811         } else if (error != 0) {
 812                 relpbuf(bp, freecnt);
 813                 return (VM_PAGER_ERROR);
 814         }
 815
 816         /*
 817          * If the file system supports BMAP, but blocksize is smaller
 818          * than a page size, then use special small filesystem code.
 819          */
 820         if (pagesperblock == 0) {
 821                 relpbuf(bp, freecnt);
 822                 for (i = 0; i < count; i++) {
 823                         PCPU_INC(cnt.v_vnodein);
 824                         PCPU_INC(cnt.v_vnodepgsin);
 825                         error = vnode_pager_input_smlfs(object, m[i]);
 826                         if (error)
 827                                 break;
 828                 }
 829                 return (error);
 830         }
 831
 832         /*
 833          * A sparse file can be encountered only for a single page request,
 834          * which may not be preceded by call to vm_pager_haspage().
 835          */
 836         if (bp->b_blkno == -1) {
 837                 KASSERT(count == 1,
 838                     ("%s: array[%d] request to a sparse file %p", __func__,
 839                     count, vp));
 840                 relpbuf(bp, freecnt);
 841                 pmap_zero_page(m[0]);
 842                 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
 843                     __func__, m[0]));
 844                 VM_OBJECT_WLOCK(object);
 845                 m[0]->valid = VM_PAGE_BITS_ALL;
 846                 VM_OBJECT_WUNLOCK(object);
 847                 return (VM_PAGER_OK);
 848         }
 849
 850         bp->b_blkno += (foff % bsize) / DEV_BSIZE;
 851
 852         /* Recalculate blocks available after/before to pages. */
 853         poff = (foff % bsize) / PAGE_SIZE;
 854         before *= pagesperblock;
 855         before += poff;
 856         after *= pagesperblock;
 857         after += pagesperblock - (poff + 1);
 858         if (m[0]->pindex + after >= object->size)
 859                 after = object->size - 1 - m[0]->pindex;
 860         KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
 861             __func__, count, after + 1));
 862         after -= count - 1;
 863
 864         /* Trim requested rbehind/rahead to possible values. */
 865         rbehind = a_rbehind ? *a_rbehind : 0;
 866         rahead = a_rahead ? *a_rahead : 0;
 867         rbehind = min(rbehind, before);
 868         rbehind = min(rbehind, m[0]->pindex);
 869         rahead = min(rahead, after);
 870         rahead = min(rahead, object->size - m[count - 1]->pindex);
 871         KASSERT(rbehind + rahead + count <= sizeof(bp->b_pages),
 872             ("%s: behind %d ahead %d count %d", __func__,
 873             rbehind, rahead, count));
 874
 875         /*
 876          * Fill in the bp->b_pages[] array with requested and optional
 877          * read behind or read ahead pages.  Read behind pages are looked
 878          * up in a backward direction, down to a first cached page.  Same
 879          * for read ahead pages, but there is no need to shift the array
 880          * in case of encountering a cached page.
 881          */
 882         i = bp->b_npages = 0;
 883         if (rbehind) {
 884                 vm_pindex_t startpindex, tpindex;
 885                 vm_page_t p;
 886
 887                 VM_OBJECT_WLOCK(object);
 888                 startpindex = m[0]->pindex - rbehind;
 889                 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
 890                     p->pindex >= startpindex)
 891                         startpindex = p->pindex + 1;
 892
 893                 /* tpindex is unsigned; beware of numeric underflow. */
 894                 for (tpindex = m[0]->pindex - 1;
 895                     tpindex >= startpindex && tpindex < m[0]->pindex;
 896                     tpindex--, i++) {
 897                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 898                             VM_ALLOC_IFNOTCACHED);
 899                         if (p == NULL) {
 900                                 /* Shift the array. */
 901                                 for (int j = 0; j < i; j++)
 902                                         bp->b_pages[j] = bp->b_pages[j +
 903                                             tpindex + 1 - startpindex];
 904                                 break;
 905                         }
 906                         bp->b_pages[tpindex - startpindex] = p;
 907                 }
 908
 909                 bp->b_pgbefore = i;
 910                 bp->b_npages += i;
 911                 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
 912         } else
 913                 bp->b_pgbefore = 0;
 914
 915         /* Requested pages. */
 916         for (int j = 0; j < count; j++, i++)
 917                 bp->b_pages[i] = m[j];
 918         bp->b_npages += count;
 919
 920         if (rahead) {
 921                 vm_pindex_t endpindex, tpindex;
 922                 vm_page_t p;
 923
 924                 if (!VM_OBJECT_WOWNED(object))
 925                         VM_OBJECT_WLOCK(object);
 926                 endpindex = m[count - 1]->pindex + rahead + 1;
 927                 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
 928                     p->pindex < endpindex)
 929                         endpindex = p->pindex;
 930                 if (endpindex > object->size)
 931                         endpindex = object->size;
 932
 933                 for (tpindex = m[count - 1]->pindex + 1;
 934                     tpindex < endpindex; i++, tpindex++) {
 935                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL |
 936                             VM_ALLOC_IFNOTCACHED);
 937                         if (p == NULL)
 938                                 break;
 939                         bp->b_pages[i] = p;
 940                 }
 941
 942                 bp->b_pgafter = i - bp->b_npages;
 943                 bp->b_npages = i;
 944         } else
 945                 bp->b_pgafter = 0;
 946
 947         if (VM_OBJECT_WOWNED(object))
 948                 VM_OBJECT_WUNLOCK(object);
 949
 950         /* Report back actual behind/ahead read. */
 951         if (a_rbehind)
 952                 *a_rbehind = bp->b_pgbefore;
 953         if (a_rahead)
 954                 *a_rahead = bp->b_pgafter;
 955
 956         KASSERT(bp->b_npages <= nitems(bp->b_pages),
 957             ("%s: buf %p overflowed", __func__, bp));
 958
 959         /*
 960          * Recalculate first offset and bytecount with regards to read behind.
 961          * Truncate bytecount to vnode real size and round up physical size
 962          * for real devices.
 963          */
 964         foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
 965         bytecount = bp->b_npages << PAGE_SHIFT;
 966         if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
 967                 bytecount = object->un_pager.vnp.vnp_size - foff;
 968         secmask = bo->bo_bsize - 1;
 969         KASSERT(secmask < PAGE_SIZE && secmask > 0,
 970             ("%s: sector size %d too large", __func__, secmask + 1));
 971         bytecount = (bytecount + secmask) & ~secmask;
 972
 973         /*
 974          * And map the pages to be read into the kva, if the filesystem
 975          * requires mapped buffers.
 976          */
 977         if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
 978             unmapped_buf_allowed) {
 979                 bp->b_data = unmapped_buf;
 980                 bp->b_offset = 0;
 981         } else {
 982                 bp->b_data = bp->b_kvabase;
 983                 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
 984         }
 985
 986         /* Build a minimal buffer header. */
 987         bp->b_iocmd = BIO_READ;
 988         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 989         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 990         bp->b_rcred = crhold(curthread->td_ucred);
 991         bp->b_wcred = crhold(curthread->td_ucred);
 992         pbgetbo(bo, bp);
 993         bp->b_vp = vp;
 994         bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
 995         bp->b_iooffset = dbtob(bp->b_blkno);
 996
 997         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 998         PCPU_INC(cnt.v_vnodein);
 999         PCPU_ADD(cnt.v_vnodepgsin, bp->b_npages);
1000
1001         if (iodone != NULL) { /* async */
1002                 bp->b_pgiodone = iodone;
1003                 bp->b_caller1 = arg;
1004                 bp->b_iodone = vnode_pager_generic_getpages_done_async;
1005                 bp->b_flags |= B_ASYNC;
1006                 BUF_KERNPROC(bp);
1007                 bstrategy(bp);
1008                 return (VM_PAGER_OK);
1009         } else {
1010                 bp->b_iodone = bdone;
1011                 bstrategy(bp);
1012                 bwait(bp, PVM, "vnread");
1013                 error = vnode_pager_generic_getpages_done(bp);
1014                 for (i = 0; i < bp->b_npages; i++)
1015                         bp->b_pages[i] = NULL;
1016                 bp->b_vp = NULL;
1017                 pbrelbo(bp);
1018                 relpbuf(bp, &vnode_pbuf_freecnt);
1019                 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
1020         }
1021 }
1022
1023 static void
1024 vnode_pager_generic_getpages_done_async(struct buf *bp)
1025 {
1026         int error;
1027
1028         error = vnode_pager_generic_getpages_done(bp);
1029         /* Run the iodone upon the requested range. */
1030         bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
1031             bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
1032         for (int i = 0; i < bp->b_npages; i++)
1033                 bp->b_pages[i] = NULL;
1034         bp->b_vp = NULL;
1035         pbrelbo(bp);
1036         relpbuf(bp, &vnode_async_pbuf_freecnt);
1037 }
1038
1039 static int
1040 vnode_pager_generic_getpages_done(struct buf *bp)
1041 {
1042         vm_object_t object;
1043         off_t tfoff, nextoff;
1044         int i, error;
1045
1046         error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0;
1047         object = bp->b_vp->v_object;
1048
1049         if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
1050                 if (!buf_mapped(bp)) {
1051                         bp->b_data = bp->b_kvabase;
1052                         pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
1053                             bp->b_npages);
1054                 }
1055                 bzero(bp->b_data + bp->b_bcount,
1056                     PAGE_SIZE * bp->b_npages - bp->b_bcount);
1057         }
1058         if (buf_mapped(bp)) {
1059                 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1060                 bp->b_data = unmapped_buf;
1061         }
1062
1063         VM_OBJECT_WLOCK(object);
1064         for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1065             i < bp->b_npages; i++, tfoff = nextoff) {
1066                 vm_page_t mt;
1067
1068                 nextoff = tfoff + PAGE_SIZE;
1069                 mt = bp->b_pages[i];
1070
1071                 if (nextoff <= object->un_pager.vnp.vnp_size) {
1072                         /*
1073                          * Read filled up entire page.
1074                          */
1075                         mt->valid = VM_PAGE_BITS_ALL;
1076                         KASSERT(mt->dirty == 0,
1077                             ("%s: page %p is dirty", __func__, mt));
1078                         KASSERT(!pmap_page_is_mapped(mt),
1079                             ("%s: page %p is mapped", __func__, mt));
1080                 } else {
1081                         /*
1082                          * Read did not fill up entire page.
1083                          *
1084                          * Currently we do not set the entire page valid,
1085                          * we just try to clear the piece that we couldn't
1086                          * read.
1087                          */
1088                         vm_page_set_valid_range(mt, 0,
1089                             object->un_pager.vnp.vnp_size - tfoff);
1090                         KASSERT((mt->dirty & vm_page_bits(0,
1091                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
1092                             ("%s: page %p is dirty", __func__, mt));
1093                 }
1094
1095                 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
1096                         vm_page_readahead_finish(mt);
1097         }
1098         VM_OBJECT_WUNLOCK(object);
1099         if (error != 0)
1100                 printf("%s: I/O read error %d\n", __func__, error);
1101
1102         return (error);
1103 }
1104
1105 /*
1106  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1107  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1108  * vnode_pager_generic_putpages() to implement the previous behaviour.
1109  *
1110  * All other FS's should use the bypass to get to the local media
1111  * backing vp's VOP_PUTPAGES.
1112  */
1113 static void
1114 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1115     int flags, int *rtvals)
1116 {
1117         int rtval;
1118         struct vnode *vp;
1119         int bytes = count * PAGE_SIZE;
1120
1121         /*
1122          * Force synchronous operation if we are extremely low on memory
1123          * to prevent a low-memory deadlock.  VOP operations often need to
1124          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1125          * operation ).  The swapper handles the case by limiting the amount
1126          * of asynchronous I/O, but that sort of solution doesn't scale well
1127          * for the vnode pager without a lot of work.
1128          *
1129          * Also, the backing vnode's iodone routine may not wake the pageout
1130          * daemon up.  This should be probably be addressed XXX.
1131          */
1132
1133         if (vm_cnt.v_free_count + vm_cnt.v_cache_count <
1134             vm_cnt.v_pageout_free_min)
1135                 flags |= VM_PAGER_PUT_SYNC;
1136
1137         /*
1138          * Call device-specific putpages function
1139          */
1140         vp = object->handle;
1141         VM_OBJECT_WUNLOCK(object);
1142         rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
1143         KASSERT(rtval != EOPNOTSUPP,
1144             ("vnode_pager: stale FS putpages\n"));
1145         VM_OBJECT_WLOCK(object);
1146 }
1147
1148
1149 /*
1150  * This is now called from local media FS's to operate against their
1151  * own vnodes if they fail to implement VOP_PUTPAGES.
1152  *
1153  * This is typically called indirectly via the pageout daemon and
1154  * clustering has already typically occurred, so in general we ask the
1155  * underlying filesystem to write the data out asynchronously rather
1156  * then delayed.
1157  */
1158 int
1159 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1160     int flags, int *rtvals)
1161 {
1162         int i;
1163         vm_object_t object;
1164         vm_page_t m;
1165         int count;
1166
1167         int maxsize, ncount;
1168         vm_ooffset_t poffset;
1169         struct uio auio;
1170         struct iovec aiov;
1171         int error;
1172         int ioflags;
1173         int ppscheck = 0;
1174         static struct timeval lastfail;
1175         static int curfail;
1176
1177         object = vp->v_object;
1178         count = bytecount / PAGE_SIZE;
1179
1180         for (i = 0; i < count; i++)
1181                 rtvals[i] = VM_PAGER_ERROR;
1182
1183         if ((int64_t)ma[0]->pindex < 0) {
1184                 printf("vnode_pager_putpages: attempt to write meta-data!!! -- 0x%lx(%lx)\n",
1185                     (long)ma[0]->pindex, (u_long)ma[0]->dirty);
1186                 rtvals[0] = VM_PAGER_BAD;
1187                 return VM_PAGER_BAD;
1188         }
1189
1190         maxsize = count * PAGE_SIZE;
1191         ncount = count;
1192
1193         poffset = IDX_TO_OFF(ma[0]->pindex);
1194
1195         /*
1196          * If the page-aligned write is larger then the actual file we
1197          * have to invalidate pages occurring beyond the file EOF.  However,
1198          * there is an edge case where a file may not be page-aligned where
1199          * the last page is partially invalid.  In this case the filesystem
1200          * may not properly clear the dirty bits for the entire page (which
1201          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1202          * With the page locked we are free to fix-up the dirty bits here.
1203          *
1204          * We do not under any circumstances truncate the valid bits, as
1205          * this will screw up bogus page replacement.
1206          */
1207         VM_OBJECT_WLOCK(object);
1208         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1209                 if (object->un_pager.vnp.vnp_size > poffset) {
1210                         int pgoff;
1211
1212                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1213                         ncount = btoc(maxsize);
1214                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1215                                 /*
1216                                  * If the object is locked and the following
1217                                  * conditions hold, then the page's dirty
1218                                  * field cannot be concurrently changed by a
1219                                  * pmap operation.
1220                                  */
1221                                 m = ma[ncount - 1];
1222                                 vm_page_assert_sbusied(m);
1223                                 KASSERT(!pmap_page_is_write_mapped(m),
1224                 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1225                                 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1226                                     pgoff);
1227                         }
1228                 } else {
1229                         maxsize = 0;
1230                         ncount = 0;
1231                 }
1232                 if (ncount < count) {
1233                         for (i = ncount; i < count; i++) {
1234                                 rtvals[i] = VM_PAGER_BAD;
1235                         }
1236                 }
1237         }
1238         VM_OBJECT_WUNLOCK(object);
1239
1240         /*
1241          * pageouts are already clustered, use IO_ASYNC to force a bawrite()
1242          * rather then a bdwrite() to prevent paging I/O from saturating
1243          * the buffer cache.  Dummy-up the sequential heuristic to cause
1244          * large ranges to cluster.  If neither IO_SYNC or IO_ASYNC is set,
1245          * the system decides how to cluster.
1246          */
1247         ioflags = IO_VMIO;
1248         if (flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL))
1249                 ioflags |= IO_SYNC;
1250         else if ((flags & VM_PAGER_CLUSTER_OK) == 0)
1251                 ioflags |= IO_ASYNC;
1252         ioflags |= (flags & VM_PAGER_PUT_INVAL) ? IO_INVAL: 0;
1253         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1254
1255         aiov.iov_base = (caddr_t) 0;
1256         aiov.iov_len = maxsize;
1257         auio.uio_iov = &aiov;
1258         auio.uio_iovcnt = 1;
1259         auio.uio_offset = poffset;
1260         auio.uio_segflg = UIO_NOCOPY;
1261         auio.uio_rw = UIO_WRITE;
1262         auio.uio_resid = maxsize;
1263         auio.uio_td = (struct thread *) 0;
1264         error = VOP_WRITE(vp, &auio, ioflags, curthread->td_ucred);
1265         PCPU_INC(cnt.v_vnodeout);
1266         PCPU_ADD(cnt.v_vnodepgsout, ncount);
1267
1268         if (error) {
1269                 if ((ppscheck = ppsratecheck(&lastfail, &curfail, 1)))
1270                         printf("vnode_pager_putpages: I/O error %d\n", error);
1271         }
1272         if (auio.uio_resid) {
1273                 if (ppscheck || ppsratecheck(&lastfail, &curfail, 1))
1274                         printf("vnode_pager_putpages: residual I/O %zd at %lu\n",
1275                             auio.uio_resid, (u_long)ma[0]->pindex);
1276         }
1277         for (i = 0; i < ncount; i++) {
1278                 rtvals[i] = VM_PAGER_OK;
1279         }
1280         return rtvals[0];
1281 }
1282
1283 void
1284 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written)
1285 {
1286         vm_object_t obj;
1287         int i, pos;
1288
1289         if (written == 0)
1290                 return;
1291         obj = ma[0]->object;
1292         VM_OBJECT_WLOCK(obj);
1293         for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1294                 if (pos < trunc_page(written)) {
1295                         rtvals[i] = VM_PAGER_OK;
1296                         vm_page_undirty(ma[i]);
1297                 } else {
1298                         /* Partially written page. */
1299                         rtvals[i] = VM_PAGER_AGAIN;
1300                         vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1301                 }
1302         }
1303         VM_OBJECT_WUNLOCK(obj);
1304 }
1305
1306 void
1307 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1308     vm_offset_t end)
1309 {
1310         struct vnode *vp;
1311         vm_ooffset_t old_wm;
1312
1313         VM_OBJECT_WLOCK(object);
1314         if (object->type != OBJT_VNODE) {
1315                 VM_OBJECT_WUNLOCK(object);
1316                 return;
1317         }
1318         old_wm = object->un_pager.vnp.writemappings;
1319         object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1320         vp = object->handle;
1321         if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1322                 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1323                 VOP_ADD_WRITECOUNT(vp, 1);
1324                 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1325                     __func__, vp, vp->v_writecount);
1326         } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1327                 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1328                 VOP_ADD_WRITECOUNT(vp, -1);
1329                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1330                     __func__, vp, vp->v_writecount);
1331         }
1332         VM_OBJECT_WUNLOCK(object);
1333 }
1334
1335 void
1336 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1337     vm_offset_t end)
1338 {
1339         struct vnode *vp;
1340         struct mount *mp;
1341         vm_offset_t inc;
1342
1343         VM_OBJECT_WLOCK(object);
1344
1345         /*
1346          * First, recheck the object type to account for the race when
1347          * the vnode is reclaimed.
1348          */
1349         if (object->type != OBJT_VNODE) {
1350                 VM_OBJECT_WUNLOCK(object);
1351                 return;
1352         }
1353
1354         /*
1355          * Optimize for the case when writemappings is not going to
1356          * zero.
1357          */
1358         inc = end - start;
1359         if (object->un_pager.vnp.writemappings != inc) {
1360                 object->un_pager.vnp.writemappings -= inc;
1361                 VM_OBJECT_WUNLOCK(object);
1362                 return;
1363         }
1364
1365         vp = object->handle;
1366         vhold(vp);
1367         VM_OBJECT_WUNLOCK(object);
1368         mp = NULL;
1369         vn_start_write(vp, &mp, V_WAIT);
1370         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1371
1372         /*
1373          * Decrement the object's writemappings, by swapping the start
1374          * and end arguments for vnode_pager_update_writecount().  If
1375          * there was not a race with vnode reclaimation, then the
1376          * vnode's v_writecount is decremented.
1377          */
1378         vnode_pager_update_writecount(object, end, start);
1379         VOP_UNLOCK(vp, 0);
1380         vdrop(vp);
1381         if (mp != NULL)
1382                 vn_finished_write(mp);
1383 }