sys/vm/vnode_pager.c

   1 /*-
   2  * SPDX-License-Identifier: BSD-4-Clause
   3  *
   4  * Copyright (c) 1990 University of Utah.
   5  * Copyright (c) 1991 The Regents of the University of California.
   6  * All rights reserved.
   7  * Copyright (c) 1993, 1994 John S. Dyson
   8  * Copyright (c) 1995, David Greenman
   9  *
  10  * This code is derived from software contributed to Berkeley by
  11  * the Systems Programming Group of the University of Utah Computer
  12  * Science Department.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions
  16  * are met:
  17  * 1. Redistributions of source code must retain the above copyright
  18  *    notice, this list of conditions and the following disclaimer.
  19  * 2. Redistributions in binary form must reproduce the above copyright
  20  *    notice, this list of conditions and the following disclaimer in the
  21  *    documentation and/or other materials provided with the distribution.
  22  * 3. All advertising materials mentioning features or use of this software
  23  *    must display the following acknowledgement:
  24  *      This product includes software developed by the University of
  25  *      California, Berkeley and its contributors.
  26  * 4. Neither the name of the University nor the names of its contributors
  27  *    may be used to endorse or promote products derived from this software
  28  *    without specific prior written permission.
  29  *
  30  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  31  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  32  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  33  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  34  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  35  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  36  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  37  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  38  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  39  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  40  * SUCH DAMAGE.
  41  *
  42  *      from: @(#)vnode_pager.c 7.5 (Berkeley) 4/20/91
  43  */
  44
  45 /*
  46  * Page to/from files (vnodes).
  47  */
  48
  49 /*
  50  * TODO:
  51  *      Implement VOP_GETPAGES/PUTPAGES interface for filesystems. Will
  52  *      greatly re-simplify the vnode_pager.
  53  */
  54
  55 #include <sys/cdefs.h>
  56 __FBSDID("$FreeBSD$");
  57
  58 #include "opt_vm.h"
  59
  60 #include <sys/param.h>
  61 #include <sys/systm.h>
  62 #include <sys/proc.h>
  63 #include <sys/vnode.h>
  64 #include <sys/mount.h>
  65 #include <sys/bio.h>
  66 #include <sys/buf.h>
  67 #include <sys/vmmeter.h>
  68 #include <sys/limits.h>
  69 #include <sys/conf.h>
  70 #include <sys/rwlock.h>
  71 #include <sys/sf_buf.h>
  72
  73 #include <machine/atomic.h>
  74
  75 #include <vm/vm.h>
  76 #include <vm/vm_param.h>
  77 #include <vm/vm_object.h>
  78 #include <vm/vm_page.h>
  79 #include <vm/vm_pager.h>
  80 #include <vm/vm_map.h>
  81 #include <vm/vnode_pager.h>
  82 #include <vm/vm_extern.h>
  83
  84 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
  85     daddr_t *rtaddress, int *run);
  86 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
  87 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
  88 static void vnode_pager_dealloc(vm_object_t);
  89 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
  90 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *,
  91     int *, vop_getpages_iodone_t, void *);
  92 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
  93 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  94 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  95     vm_ooffset_t, struct ucred *cred);
  96 static int vnode_pager_generic_getpages_done(struct buf *);
  97 static void vnode_pager_generic_getpages_done_async(struct buf *);
  98
  99 struct pagerops vnodepagerops = {
 100         .pgo_alloc =    vnode_pager_alloc,
 101         .pgo_dealloc =  vnode_pager_dealloc,
 102         .pgo_getpages = vnode_pager_getpages,
 103         .pgo_getpages_async = vnode_pager_getpages_async,
 104         .pgo_putpages = vnode_pager_putpages,
 105         .pgo_haspage =  vnode_pager_haspage,
 106 };
 107
 108 int vnode_pbuf_freecnt;
 109 int vnode_async_pbuf_freecnt;
 110
 111 /* Create the VM system backing object for this vnode */
 112 int
 113 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
 114 {
 115         vm_object_t object;
 116         vm_ooffset_t size = isize;
 117         struct vattr va;
 118
 119         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
 120                 return (0);
 121
 122         while ((object = vp->v_object) != NULL) {
 123                 VM_OBJECT_WLOCK(object);
 124                 if (!(object->flags & OBJ_DEAD)) {
 125                         VM_OBJECT_WUNLOCK(object);
 126                         return (0);
 127                 }
 128                 VOP_UNLOCK(vp, 0);
 129                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 130                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0);
 131                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 132         }
 133
 134         if (size == 0) {
 135                 if (vn_isdisk(vp, NULL)) {
 136                         size = IDX_TO_OFF(INT_MAX);
 137                 } else {
 138                         if (VOP_GETATTR(vp, &va, td->td_ucred))
 139                                 return (0);
 140                         size = va.va_size;
 141                 }
 142         }
 143
 144         object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
 145         /*
 146          * Dereference the reference we just created.  This assumes
 147          * that the object is associated with the vp.
 148          */
 149         VM_OBJECT_WLOCK(object);
 150         object->ref_count--;
 151         VM_OBJECT_WUNLOCK(object);
 152         vrele(vp);
 153
 154         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
 155
 156         return (0);
 157 }
 158
 159 void
 160 vnode_destroy_vobject(struct vnode *vp)
 161 {
 162         struct vm_object *obj;
 163
 164         obj = vp->v_object;
 165         if (obj == NULL)
 166                 return;
 167         ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
 168         VM_OBJECT_WLOCK(obj);
 169         umtx_shm_object_terminated(obj);
 170         if (obj->ref_count == 0) {
 171                 /*
 172                  * don't double-terminate the object
 173                  */
 174                 if ((obj->flags & OBJ_DEAD) == 0) {
 175                         vm_object_terminate(obj);
 176                 } else {
 177                         /*
 178                          * Waiters were already handled during object
 179                          * termination.  The exclusive vnode lock hopefully
 180                          * prevented new waiters from referencing the dying
 181                          * object.
 182                          */
 183                         KASSERT((obj->flags & OBJ_DISCONNECTWNT) == 0,
 184                             ("OBJ_DISCONNECTWNT set obj %p flags %x",
 185                             obj, obj->flags));
 186                         vp->v_object = NULL;
 187                         VM_OBJECT_WUNLOCK(obj);
 188                 }
 189         } else {
 190                 /*
 191                  * Woe to the process that tries to page now :-).
 192                  */
 193                 vm_pager_deallocate(obj);
 194                 VM_OBJECT_WUNLOCK(obj);
 195         }
 196         KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object));
 197 }
 198
 199
 200 /*
 201  * Allocate (or lookup) pager for a vnode.
 202  * Handle is a vnode pointer.
 203  *
 204  * MPSAFE
 205  */
 206 vm_object_t
 207 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 208     vm_ooffset_t offset, struct ucred *cred)
 209 {
 210         vm_object_t object;
 211         struct vnode *vp;
 212
 213         /*
 214          * Pageout to vnode, no can do yet.
 215          */
 216         if (handle == NULL)
 217                 return (NULL);
 218
 219         vp = (struct vnode *) handle;
 220
 221         /*
 222          * If the object is being terminated, wait for it to
 223          * go away.
 224          */
 225 retry:
 226         while ((object = vp->v_object) != NULL) {
 227                 VM_OBJECT_WLOCK(object);
 228                 if ((object->flags & OBJ_DEAD) == 0)
 229                         break;
 230                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 231                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
 232         }
 233
 234         KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
 235
 236         if (object == NULL) {
 237                 /*
 238                  * Add an object of the appropriate size
 239                  */
 240                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 241
 242                 object->un_pager.vnp.vnp_size = size;
 243                 object->un_pager.vnp.writemappings = 0;
 244
 245                 object->handle = handle;
 246                 VI_LOCK(vp);
 247                 if (vp->v_object != NULL) {
 248                         /*
 249                          * Object has been created while we were sleeping
 250                          */
 251                         VI_UNLOCK(vp);
 252                         VM_OBJECT_WLOCK(object);
 253                         KASSERT(object->ref_count == 1,
 254                             ("leaked ref %p %d", object, object->ref_count));
 255                         object->type = OBJT_DEAD;
 256                         object->ref_count = 0;
 257                         VM_OBJECT_WUNLOCK(object);
 258                         vm_object_destroy(object);
 259                         goto retry;
 260                 }
 261                 vp->v_object = object;
 262                 VI_UNLOCK(vp);
 263         } else {
 264                 object->ref_count++;
 265 #if VM_NRESERVLEVEL > 0
 266                 vm_object_color(object, 0);
 267 #endif
 268                 VM_OBJECT_WUNLOCK(object);
 269         }
 270         vrefact(vp);
 271         return (object);
 272 }
 273
 274 /*
 275  *      The object must be locked.
 276  */
 277 static void
 278 vnode_pager_dealloc(vm_object_t object)
 279 {
 280         struct vnode *vp;
 281         int refs;
 282
 283         vp = object->handle;
 284         if (vp == NULL)
 285                 panic("vnode_pager_dealloc: pager already dealloced");
 286
 287         VM_OBJECT_ASSERT_WLOCKED(object);
 288         vm_object_pip_wait(object, "vnpdea");
 289         refs = object->ref_count;
 290
 291         object->handle = NULL;
 292         object->type = OBJT_DEAD;
 293         if (object->flags & OBJ_DISCONNECTWNT) {
 294                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 295                 wakeup(object);
 296         }
 297         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 298         if (object->un_pager.vnp.writemappings > 0) {
 299                 object->un_pager.vnp.writemappings = 0;
 300                 VOP_ADD_WRITECOUNT(vp, -1);
 301                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
 302                     __func__, vp, vp->v_writecount);
 303         }
 304         vp->v_object = NULL;
 305         VOP_UNSET_TEXT(vp);
 306         VM_OBJECT_WUNLOCK(object);
 307         while (refs-- > 0)
 308                 vunref(vp);
 309         VM_OBJECT_WLOCK(object);
 310 }
 311
 312 static boolean_t
 313 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 314     int *after)
 315 {
 316         struct vnode *vp = object->handle;
 317         daddr_t bn;
 318         int err;
 319         daddr_t reqblock;
 320         int poff;
 321         int bsize;
 322         int pagesperblock, blocksperpage;
 323
 324         VM_OBJECT_ASSERT_WLOCKED(object);
 325         /*
 326          * If no vp or vp is doomed or marked transparent to VM, we do not
 327          * have the page.
 328          */
 329         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 330                 return FALSE;
 331         /*
 332          * If the offset is beyond end of file we do
 333          * not have the page.
 334          */
 335         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 336                 return FALSE;
 337
 338         bsize = vp->v_mount->mnt_stat.f_iosize;
 339         pagesperblock = bsize / PAGE_SIZE;
 340         blocksperpage = 0;
 341         if (pagesperblock > 0) {
 342                 reqblock = pindex / pagesperblock;
 343         } else {
 344                 blocksperpage = (PAGE_SIZE / bsize);
 345                 reqblock = pindex * blocksperpage;
 346         }
 347         VM_OBJECT_WUNLOCK(object);
 348         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 349         VM_OBJECT_WLOCK(object);
 350         if (err)
 351                 return TRUE;
 352         if (bn == -1)
 353                 return FALSE;
 354         if (pagesperblock > 0) {
 355                 poff = pindex - (reqblock * pagesperblock);
 356                 if (before) {
 357                         *before *= pagesperblock;
 358                         *before += poff;
 359                 }
 360                 if (after) {
 361                         /*
 362                          * The BMAP vop can report a partial block in the
 363                          * 'after', but must not report blocks after EOF.
 364                          * Assert the latter, and truncate 'after' in case
 365                          * of the former.
 366                          */
 367                         KASSERT((reqblock + *after) * pagesperblock <
 368                             roundup2(object->size, pagesperblock),
 369                             ("%s: reqblock %jd after %d size %ju", __func__,
 370                             (intmax_t )reqblock, *after,
 371                             (uintmax_t )object->size));
 372                         *after *= pagesperblock;
 373                         *after += pagesperblock - (poff + 1);
 374                         if (pindex + *after >= object->size)
 375                                 *after = object->size - 1 - pindex;
 376                 }
 377         } else {
 378                 if (before) {
 379                         *before /= blocksperpage;
 380                 }
 381
 382                 if (after) {
 383                         *after /= blocksperpage;
 384                 }
 385         }
 386         return TRUE;
 387 }
 388
 389 /*
 390  * Lets the VM system know about a change in size for a file.
 391  * We adjust our own internal size and flush any cached pages in
 392  * the associated object that are affected by the size change.
 393  *
 394  * Note: this routine may be invoked as a result of a pager put
 395  * operation (possibly at object termination time), so we must be careful.
 396  */
 397 void
 398 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
 399 {
 400         vm_object_t object;
 401         vm_page_t m;
 402         vm_pindex_t nobjsize;
 403
 404         if ((object = vp->v_object) == NULL)
 405                 return;
 406 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 407         VM_OBJECT_WLOCK(object);
 408         if (object->type == OBJT_DEAD) {
 409                 VM_OBJECT_WUNLOCK(object);
 410                 return;
 411         }
 412         KASSERT(object->type == OBJT_VNODE,
 413             ("not vnode-backed object %p", object));
 414         if (nsize == object->un_pager.vnp.vnp_size) {
 415                 /*
 416                  * Hasn't changed size
 417                  */
 418                 VM_OBJECT_WUNLOCK(object);
 419                 return;
 420         }
 421         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 422         if (nsize < object->un_pager.vnp.vnp_size) {
 423                 /*
 424                  * File has shrunk. Toss any cached pages beyond the new EOF.
 425                  */
 426                 if (nobjsize < object->size)
 427                         vm_object_page_remove(object, nobjsize, object->size,
 428                             0);
 429                 /*
 430                  * this gets rid of garbage at the end of a page that is now
 431                  * only partially backed by the vnode.
 432                  *
 433                  * XXX for some reason (I don't know yet), if we take a
 434                  * completely invalid page and mark it partially valid
 435                  * it can screw up NFS reads, so we don't allow the case.
 436                  */
 437                 if ((nsize & PAGE_MASK) &&
 438                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 439                     m->valid != 0) {
 440                         int base = (int)nsize & PAGE_MASK;
 441                         int size = PAGE_SIZE - base;
 442
 443                         /*
 444                          * Clear out partial-page garbage in case
 445                          * the page has been mapped.
 446                          */
 447                         pmap_zero_page_area(m, base, size);
 448
 449                         /*
 450                          * Update the valid bits to reflect the blocks that
 451                          * have been zeroed.  Some of these valid bits may
 452                          * have already been set.
 453                          */
 454                         vm_page_set_valid_range(m, base, size);
 455
 456                         /*
 457                          * Round "base" to the next block boundary so that the
 458                          * dirty bit for a partially zeroed block is not
 459                          * cleared.
 460                          */
 461                         base = roundup2(base, DEV_BSIZE);
 462
 463                         /*
 464                          * Clear out partial-page dirty bits.
 465                          *
 466                          * note that we do not clear out the valid
 467                          * bits.  This would prevent bogus_page
 468                          * replacement from working properly.
 469                          */
 470                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 471                 }
 472         }
 473         object->un_pager.vnp.vnp_size = nsize;
 474         object->size = nobjsize;
 475         VM_OBJECT_WUNLOCK(object);
 476 }
 477
 478 /*
 479  * calculate the linear (byte) disk address of specified virtual
 480  * file address
 481  */
 482 static int
 483 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 484     int *run)
 485 {
 486         int bsize;
 487         int err;
 488         daddr_t vblock;
 489         daddr_t voffset;
 490
 491         if (address < 0)
 492                 return -1;
 493
 494         if (vp->v_iflag & VI_DOOMED)
 495                 return -1;
 496
 497         bsize = vp->v_mount->mnt_stat.f_iosize;
 498         vblock = address / bsize;
 499         voffset = address % bsize;
 500
 501         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 502         if (err == 0) {
 503                 if (*rtaddress != -1)
 504                         *rtaddress += voffset / DEV_BSIZE;
 505                 if (run) {
 506                         *run += 1;
 507                         *run *= bsize/PAGE_SIZE;
 508                         *run -= voffset/PAGE_SIZE;
 509                 }
 510         }
 511
 512         return (err);
 513 }
 514
 515 /*
 516  * small block filesystem vnode pager input
 517  */
 518 static int
 519 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
 520 {
 521         struct vnode *vp;
 522         struct bufobj *bo;
 523         struct buf *bp;
 524         struct sf_buf *sf;
 525         daddr_t fileaddr;
 526         vm_offset_t bsize;
 527         vm_page_bits_t bits;
 528         int error, i;
 529
 530         error = 0;
 531         vp = object->handle;
 532         if (vp->v_iflag & VI_DOOMED)
 533                 return VM_PAGER_BAD;
 534
 535         bsize = vp->v_mount->mnt_stat.f_iosize;
 536
 537         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 538
 539         sf = sf_buf_alloc(m, 0);
 540
 541         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 542                 vm_ooffset_t address;
 543
 544                 bits = vm_page_bits(i * bsize, bsize);
 545                 if (m->valid & bits)
 546                         continue;
 547
 548                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 549                 if (address >= object->un_pager.vnp.vnp_size) {
 550                         fileaddr = -1;
 551                 } else {
 552                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 553                         if (error)
 554                                 break;
 555                 }
 556                 if (fileaddr != -1) {
 557                         bp = getpbuf(&vnode_pbuf_freecnt);
 558
 559                         /* build a minimal buffer header */
 560                         bp->b_iocmd = BIO_READ;
 561                         bp->b_iodone = bdone;
 562                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 563                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 564                         bp->b_rcred = crhold(curthread->td_ucred);
 565                         bp->b_wcred = crhold(curthread->td_ucred);
 566                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 567                         bp->b_blkno = fileaddr;
 568                         pbgetbo(bo, bp);
 569                         bp->b_vp = vp;
 570                         bp->b_bcount = bsize;
 571                         bp->b_bufsize = bsize;
 572                         bp->b_runningbufspace = bp->b_bufsize;
 573                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 574
 575                         /* do the input */
 576                         bp->b_iooffset = dbtob(bp->b_blkno);
 577                         bstrategy(bp);
 578
 579                         bwait(bp, PVM, "vnsrd");
 580
 581                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 582                                 error = EIO;
 583
 584                         /*
 585                          * free the buffer header back to the swap buffer pool
 586                          */
 587                         bp->b_vp = NULL;
 588                         pbrelbo(bp);
 589                         relpbuf(bp, &vnode_pbuf_freecnt);
 590                         if (error)
 591                                 break;
 592                 } else
 593                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 594                 KASSERT((m->dirty & bits) == 0,
 595                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 596                 VM_OBJECT_WLOCK(object);
 597                 m->valid |= bits;
 598                 VM_OBJECT_WUNLOCK(object);
 599         }
 600         sf_buf_free(sf);
 601         if (error) {
 602                 return VM_PAGER_ERROR;
 603         }
 604         return VM_PAGER_OK;
 605 }
 606
 607 /*
 608  * old style vnode pager input routine
 609  */
 610 static int
 611 vnode_pager_input_old(vm_object_t object, vm_page_t m)
 612 {
 613         struct uio auio;
 614         struct iovec aiov;
 615         int error;
 616         int size;
 617         struct sf_buf *sf;
 618         struct vnode *vp;
 619
 620         VM_OBJECT_ASSERT_WLOCKED(object);
 621         error = 0;
 622
 623         /*
 624          * Return failure if beyond current EOF
 625          */
 626         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 627                 return VM_PAGER_BAD;
 628         } else {
 629                 size = PAGE_SIZE;
 630                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 631                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 632                 vp = object->handle;
 633                 VM_OBJECT_WUNLOCK(object);
 634
 635                 /*
 636                  * Allocate a kernel virtual address and initialize so that
 637                  * we can use VOP_READ/WRITE routines.
 638                  */
 639                 sf = sf_buf_alloc(m, 0);
 640
 641                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 642                 aiov.iov_len = size;
 643                 auio.uio_iov = &aiov;
 644                 auio.uio_iovcnt = 1;
 645                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 646                 auio.uio_segflg = UIO_SYSSPACE;
 647                 auio.uio_rw = UIO_READ;
 648                 auio.uio_resid = size;
 649                 auio.uio_td = curthread;
 650
 651                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 652                 if (!error) {
 653                         int count = size - auio.uio_resid;
 654
 655                         if (count == 0)
 656                                 error = EINVAL;
 657                         else if (count != PAGE_SIZE)
 658                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 659                                     PAGE_SIZE - count);
 660                 }
 661                 sf_buf_free(sf);
 662
 663                 VM_OBJECT_WLOCK(object);
 664         }
 665         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 666         if (!error)
 667                 m->valid = VM_PAGE_BITS_ALL;
 668         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 669 }
 670
 671 /*
 672  * generic vnode pager input routine
 673  */
 674
 675 /*
 676  * Local media VFS's that do not implement their own VOP_GETPAGES
 677  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 678  * to implement the previous behaviour.
 679  *
 680  * All other FS's should use the bypass to get to the local media
 681  * backing vp's VOP_GETPAGES.
 682  */
 683 static int
 684 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
 685     int *rahead)
 686 {
 687         struct vnode *vp;
 688         int rtval;
 689
 690         vp = object->handle;
 691         VM_OBJECT_WUNLOCK(object);
 692         rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
 693         KASSERT(rtval != EOPNOTSUPP,
 694             ("vnode_pager: FS getpages not implemented\n"));
 695         VM_OBJECT_WLOCK(object);
 696         return rtval;
 697 }
 698
 699 static int
 700 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
 701     int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
 702 {
 703         struct vnode *vp;
 704         int rtval;
 705
 706         vp = object->handle;
 707         VM_OBJECT_WUNLOCK(object);
 708         rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
 709         KASSERT(rtval != EOPNOTSUPP,
 710             ("vnode_pager: FS getpages_async not implemented\n"));
 711         VM_OBJECT_WLOCK(object);
 712         return (rtval);
 713 }
 714
 715 /*
 716  * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
 717  * local filesystems, where partially valid pages can only occur at
 718  * the end of file.
 719  */
 720 int
 721 vnode_pager_local_getpages(struct vop_getpages_args *ap)
 722 {
 723
 724         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 725             ap->a_rbehind, ap->a_rahead, NULL, NULL));
 726 }
 727
 728 int
 729 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
 730 {
 731
 732         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 733             ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg));
 734 }
 735
 736 /*
 737  * This is now called from local media FS's to operate against their
 738  * own vnodes if they fail to implement VOP_GETPAGES.
 739  */
 740 int
 741 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
 742     int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
 743 {
 744         vm_object_t object;
 745         struct bufobj *bo;
 746         struct buf *bp;
 747         off_t foff;
 748 #ifdef INVARIANTS
 749         off_t blkno0;
 750 #endif
 751         int bsize, pagesperblock, *freecnt;
 752         int error, before, after, rbehind, rahead, poff, i;
 753         int bytecount, secmask;
 754
 755         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 756             ("%s does not support devices", __func__));
 757
 758         if (vp->v_iflag & VI_DOOMED)
 759                 return (VM_PAGER_BAD);
 760
 761         object = vp->v_object;
 762         foff = IDX_TO_OFF(m[0]->pindex);
 763         bsize = vp->v_mount->mnt_stat.f_iosize;
 764         pagesperblock = bsize / PAGE_SIZE;
 765
 766         KASSERT(foff < object->un_pager.vnp.vnp_size,
 767             ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
 768         KASSERT(count <= sizeof(bp->b_pages),
 769             ("%s: requested %d pages", __func__, count));
 770
 771         /*
 772          * The last page has valid blocks.  Invalid part can only
 773          * exist at the end of file, and the page is made fully valid
 774          * by zeroing in vm_pager_get_pages().
 775          */
 776         if (m[count - 1]->valid != 0 && --count == 0) {
 777                 if (iodone != NULL)
 778                         iodone(arg, m, 1, 0);
 779                 return (VM_PAGER_OK);
 780         }
 781
 782         /*
 783          * Synchronous and asynchronous paging operations use different
 784          * free pbuf counters.  This is done to avoid asynchronous requests
 785          * to consume all pbufs.
 786          * Allocate the pbuf at the very beginning of the function, so that
 787          * if we are low on certain kind of pbufs don't even proceed to BMAP,
 788          * but sleep.
 789          */
 790         freecnt = iodone != NULL ?
 791             &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
 792         bp = getpbuf(freecnt);
 793
 794         /*
 795          * Get the underlying device blocks for the file with VOP_BMAP().
 796          * If the file system doesn't support VOP_BMAP, use old way of
 797          * getting pages via VOP_READ.
 798          */
 799         error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
 800         if (error == EOPNOTSUPP) {
 801                 relpbuf(bp, freecnt);
 802                 VM_OBJECT_WLOCK(object);
 803                 for (i = 0; i < count; i++) {
 804                         VM_CNT_INC(v_vnodein);
 805                         VM_CNT_INC(v_vnodepgsin);
 806                         error = vnode_pager_input_old(object, m[i]);
 807                         if (error)
 808                                 break;
 809                 }
 810                 VM_OBJECT_WUNLOCK(object);
 811                 return (error);
 812         } else if (error != 0) {
 813                 relpbuf(bp, freecnt);
 814                 return (VM_PAGER_ERROR);
 815         }
 816
 817         /*
 818          * If the file system supports BMAP, but blocksize is smaller
 819          * than a page size, then use special small filesystem code.
 820          */
 821         if (pagesperblock == 0) {
 822                 relpbuf(bp, freecnt);
 823                 for (i = 0; i < count; i++) {
 824                         VM_CNT_INC(v_vnodein);
 825                         VM_CNT_INC(v_vnodepgsin);
 826                         error = vnode_pager_input_smlfs(object, m[i]);
 827                         if (error)
 828                                 break;
 829                 }
 830                 return (error);
 831         }
 832
 833         /*
 834          * A sparse file can be encountered only for a single page request,
 835          * which may not be preceded by call to vm_pager_haspage().
 836          */
 837         if (bp->b_blkno == -1) {
 838                 KASSERT(count == 1,
 839                     ("%s: array[%d] request to a sparse file %p", __func__,
 840                     count, vp));
 841                 relpbuf(bp, freecnt);
 842                 pmap_zero_page(m[0]);
 843                 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
 844                     __func__, m[0]));
 845                 VM_OBJECT_WLOCK(object);
 846                 m[0]->valid = VM_PAGE_BITS_ALL;
 847                 VM_OBJECT_WUNLOCK(object);
 848                 return (VM_PAGER_OK);
 849         }
 850
 851 #ifdef INVARIANTS
 852         blkno0 = bp->b_blkno;
 853 #endif
 854         bp->b_blkno += (foff % bsize) / DEV_BSIZE;
 855
 856         /* Recalculate blocks available after/before to pages. */
 857         poff = (foff % bsize) / PAGE_SIZE;
 858         before *= pagesperblock;
 859         before += poff;
 860         after *= pagesperblock;
 861         after += pagesperblock - (poff + 1);
 862         if (m[0]->pindex + after >= object->size)
 863                 after = object->size - 1 - m[0]->pindex;
 864         KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
 865             __func__, count, after + 1));
 866         after -= count - 1;
 867
 868         /* Trim requested rbehind/rahead to possible values. */
 869         rbehind = a_rbehind ? *a_rbehind : 0;
 870         rahead = a_rahead ? *a_rahead : 0;
 871         rbehind = min(rbehind, before);
 872         rbehind = min(rbehind, m[0]->pindex);
 873         rahead = min(rahead, after);
 874         rahead = min(rahead, object->size - m[count - 1]->pindex);
 875         /*
 876          * Check that total amount of pages fit into buf.  Trim rbehind and
 877          * rahead evenly if not.
 878          */
 879         if (rbehind + rahead + count > nitems(bp->b_pages)) {
 880                 int trim, sum;
 881
 882                 trim = rbehind + rahead + count - nitems(bp->b_pages) + 1;
 883                 sum = rbehind + rahead;
 884                 if (rbehind == before) {
 885                         /* Roundup rbehind trim to block size. */
 886                         rbehind -= roundup(trim * rbehind / sum, pagesperblock);
 887                         if (rbehind < 0)
 888                                 rbehind = 0;
 889                 } else
 890                         rbehind -= trim * rbehind / sum;
 891                 rahead -= trim * rahead / sum;
 892         }
 893         KASSERT(rbehind + rahead + count <= nitems(bp->b_pages),
 894             ("%s: behind %d ahead %d count %d", __func__,
 895             rbehind, rahead, count));
 896
 897         /*
 898          * Fill in the bp->b_pages[] array with requested and optional
 899          * read behind or read ahead pages.  Read behind pages are looked
 900          * up in a backward direction, down to a first cached page.  Same
 901          * for read ahead pages, but there is no need to shift the array
 902          * in case of encountering a cached page.
 903          */
 904         i = bp->b_npages = 0;
 905         if (rbehind) {
 906                 vm_pindex_t startpindex, tpindex;
 907                 vm_page_t p;
 908
 909                 VM_OBJECT_WLOCK(object);
 910                 startpindex = m[0]->pindex - rbehind;
 911                 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
 912                     p->pindex >= startpindex)
 913                         startpindex = p->pindex + 1;
 914
 915                 /* tpindex is unsigned; beware of numeric underflow. */
 916                 for (tpindex = m[0]->pindex - 1;
 917                     tpindex >= startpindex && tpindex < m[0]->pindex;
 918                     tpindex--, i++) {
 919                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
 920                         if (p == NULL) {
 921                                 /* Shift the array. */
 922                                 for (int j = 0; j < i; j++)
 923                                         bp->b_pages[j] = bp->b_pages[j +
 924                                             tpindex + 1 - startpindex];
 925                                 break;
 926                         }
 927                         bp->b_pages[tpindex - startpindex] = p;
 928                 }
 929
 930                 bp->b_pgbefore = i;
 931                 bp->b_npages += i;
 932                 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
 933         } else
 934                 bp->b_pgbefore = 0;
 935
 936         /* Requested pages. */
 937         for (int j = 0; j < count; j++, i++)
 938                 bp->b_pages[i] = m[j];
 939         bp->b_npages += count;
 940
 941         if (rahead) {
 942                 vm_pindex_t endpindex, tpindex;
 943                 vm_page_t p;
 944
 945                 if (!VM_OBJECT_WOWNED(object))
 946                         VM_OBJECT_WLOCK(object);
 947                 endpindex = m[count - 1]->pindex + rahead + 1;
 948                 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
 949                     p->pindex < endpindex)
 950                         endpindex = p->pindex;
 951                 if (endpindex > object->size)
 952                         endpindex = object->size;
 953
 954                 for (tpindex = m[count - 1]->pindex + 1;
 955                     tpindex < endpindex; i++, tpindex++) {
 956                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
 957                         if (p == NULL)
 958                                 break;
 959                         bp->b_pages[i] = p;
 960                 }
 961
 962                 bp->b_pgafter = i - bp->b_npages;
 963                 bp->b_npages = i;
 964         } else
 965                 bp->b_pgafter = 0;
 966
 967         if (VM_OBJECT_WOWNED(object))
 968                 VM_OBJECT_WUNLOCK(object);
 969
 970         /* Report back actual behind/ahead read. */
 971         if (a_rbehind)
 972                 *a_rbehind = bp->b_pgbefore;
 973         if (a_rahead)
 974                 *a_rahead = bp->b_pgafter;
 975
 976 #ifdef INVARIANTS
 977         KASSERT(bp->b_npages <= nitems(bp->b_pages),
 978             ("%s: buf %p overflowed", __func__, bp));
 979         for (int j = 1, prev = 0; j < bp->b_npages; j++) {
 980                 if (bp->b_pages[j] == bogus_page)
 981                         continue;
 982                 KASSERT(bp->b_pages[j]->pindex - bp->b_pages[prev]->pindex ==
 983                     j - prev, ("%s: pages array not consecutive, bp %p",
 984                      __func__, bp));
 985                 prev = j;
 986         }
 987 #endif
 988
 989         /*
 990          * Recalculate first offset and bytecount with regards to read behind.
 991          * Truncate bytecount to vnode real size and round up physical size
 992          * for real devices.
 993          */
 994         foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
 995         bytecount = bp->b_npages << PAGE_SHIFT;
 996         if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
 997                 bytecount = object->un_pager.vnp.vnp_size - foff;
 998         secmask = bo->bo_bsize - 1;
 999         KASSERT(secmask < PAGE_SIZE && secmask > 0,
1000             ("%s: sector size %d too large", __func__, secmask + 1));
1001         bytecount = (bytecount + secmask) & ~secmask;
1002
1003         /*
1004          * And map the pages to be read into the kva, if the filesystem
1005          * requires mapped buffers.
1006          */
1007         if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
1008             unmapped_buf_allowed) {
1009                 bp->b_data = unmapped_buf;
1010                 bp->b_offset = 0;
1011         } else {
1012                 bp->b_data = bp->b_kvabase;
1013                 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
1014         }
1015
1016         /* Build a minimal buffer header. */
1017         bp->b_iocmd = BIO_READ;
1018         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
1019         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
1020         bp->b_rcred = crhold(curthread->td_ucred);
1021         bp->b_wcred = crhold(curthread->td_ucred);
1022         pbgetbo(bo, bp);
1023         bp->b_vp = vp;
1024         bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
1025         bp->b_iooffset = dbtob(bp->b_blkno);
1026         KASSERT(IDX_TO_OFF(m[0]->pindex - bp->b_pages[0]->pindex) ==
1027             (blkno0 - bp->b_blkno) * DEV_BSIZE +
1028             IDX_TO_OFF(m[0]->pindex) % bsize,
1029             ("wrong offsets bsize %d m[0] %ju b_pages[0] %ju "
1030             "blkno0 %ju b_blkno %ju", bsize,
1031             (uintmax_t)m[0]->pindex, (uintmax_t)bp->b_pages[0]->pindex,
1032             (uintmax_t)blkno0, (uintmax_t)bp->b_blkno));
1033
1034         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
1035         VM_CNT_INC(v_vnodein);
1036         VM_CNT_ADD(v_vnodepgsin, bp->b_npages);
1037
1038         if (iodone != NULL) { /* async */
1039                 bp->b_pgiodone = iodone;
1040                 bp->b_caller1 = arg;
1041                 bp->b_iodone = vnode_pager_generic_getpages_done_async;
1042                 bp->b_flags |= B_ASYNC;
1043                 BUF_KERNPROC(bp);
1044                 bstrategy(bp);
1045                 return (VM_PAGER_OK);
1046         } else {
1047                 bp->b_iodone = bdone;
1048                 bstrategy(bp);
1049                 bwait(bp, PVM, "vnread");
1050                 error = vnode_pager_generic_getpages_done(bp);
1051                 for (i = 0; i < bp->b_npages; i++)
1052                         bp->b_pages[i] = NULL;
1053                 bp->b_vp = NULL;
1054                 pbrelbo(bp);
1055                 relpbuf(bp, &vnode_pbuf_freecnt);
1056                 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
1057         }
1058 }
1059
1060 static void
1061 vnode_pager_generic_getpages_done_async(struct buf *bp)
1062 {
1063         int error;
1064
1065         error = vnode_pager_generic_getpages_done(bp);
1066         /* Run the iodone upon the requested range. */
1067         bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
1068             bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
1069         for (int i = 0; i < bp->b_npages; i++)
1070                 bp->b_pages[i] = NULL;
1071         bp->b_vp = NULL;
1072         pbrelbo(bp);
1073         relpbuf(bp, &vnode_async_pbuf_freecnt);
1074 }
1075
1076 static int
1077 vnode_pager_generic_getpages_done(struct buf *bp)
1078 {
1079         vm_object_t object;
1080         off_t tfoff, nextoff;
1081         int i, error;
1082
1083         error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0;
1084         object = bp->b_vp->v_object;
1085
1086         if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
1087                 if (!buf_mapped(bp)) {
1088                         bp->b_data = bp->b_kvabase;
1089                         pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
1090                             bp->b_npages);
1091                 }
1092                 bzero(bp->b_data + bp->b_bcount,
1093                     PAGE_SIZE * bp->b_npages - bp->b_bcount);
1094         }
1095         if (buf_mapped(bp)) {
1096                 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1097                 bp->b_data = unmapped_buf;
1098         }
1099
1100         VM_OBJECT_WLOCK(object);
1101         for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1102             i < bp->b_npages; i++, tfoff = nextoff) {
1103                 vm_page_t mt;
1104
1105                 nextoff = tfoff + PAGE_SIZE;
1106                 mt = bp->b_pages[i];
1107
1108                 if (nextoff <= object->un_pager.vnp.vnp_size) {
1109                         /*
1110                          * Read filled up entire page.
1111                          */
1112                         mt->valid = VM_PAGE_BITS_ALL;
1113                         KASSERT(mt->dirty == 0,
1114                             ("%s: page %p is dirty", __func__, mt));
1115                         KASSERT(!pmap_page_is_mapped(mt),
1116                             ("%s: page %p is mapped", __func__, mt));
1117                 } else {
1118                         /*
1119                          * Read did not fill up entire page.
1120                          *
1121                          * Currently we do not set the entire page valid,
1122                          * we just try to clear the piece that we couldn't
1123                          * read.
1124                          */
1125                         vm_page_set_valid_range(mt, 0,
1126                             object->un_pager.vnp.vnp_size - tfoff);
1127                         KASSERT((mt->dirty & vm_page_bits(0,
1128                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
1129                             ("%s: page %p is dirty", __func__, mt));
1130                 }
1131
1132                 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
1133                         vm_page_readahead_finish(mt);
1134         }
1135         VM_OBJECT_WUNLOCK(object);
1136         if (error != 0)
1137                 printf("%s: I/O read error %d\n", __func__, error);
1138
1139         return (error);
1140 }
1141
1142 /*
1143  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1144  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1145  * vnode_pager_generic_putpages() to implement the previous behaviour.
1146  *
1147  * All other FS's should use the bypass to get to the local media
1148  * backing vp's VOP_PUTPAGES.
1149  */
1150 static void
1151 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1152     int flags, int *rtvals)
1153 {
1154         int rtval;
1155         struct vnode *vp;
1156         int bytes = count * PAGE_SIZE;
1157
1158         /*
1159          * Force synchronous operation if we are extremely low on memory
1160          * to prevent a low-memory deadlock.  VOP operations often need to
1161          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1162          * operation ).  The swapper handles the case by limiting the amount
1163          * of asynchronous I/O, but that sort of solution doesn't scale well
1164          * for the vnode pager without a lot of work.
1165          *
1166          * Also, the backing vnode's iodone routine may not wake the pageout
1167          * daemon up.  This should be probably be addressed XXX.
1168          */
1169
1170         if (vm_cnt.v_free_count < vm_cnt.v_pageout_free_min)
1171                 flags |= VM_PAGER_PUT_SYNC;
1172
1173         /*
1174          * Call device-specific putpages function
1175          */
1176         vp = object->handle;
1177         VM_OBJECT_WUNLOCK(object);
1178         rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
1179         KASSERT(rtval != EOPNOTSUPP,
1180             ("vnode_pager: stale FS putpages\n"));
1181         VM_OBJECT_WLOCK(object);
1182 }
1183
1184 static int
1185 vn_off2bidx(vm_ooffset_t offset)
1186 {
1187
1188         return ((offset & PAGE_MASK) / DEV_BSIZE);
1189 }
1190
1191 static bool
1192 vn_dirty_blk(vm_page_t m, vm_ooffset_t offset)
1193 {
1194
1195         KASSERT(IDX_TO_OFF(m->pindex) <= offset &&
1196             offset < IDX_TO_OFF(m->pindex + 1),
1197             ("page %p pidx %ju offset %ju", m, (uintmax_t)m->pindex,
1198             (uintmax_t)offset));
1199         return ((m->dirty & ((vm_page_bits_t)1 << vn_off2bidx(offset))) != 0);
1200 }
1201
1202 /*
1203  * This is now called from local media FS's to operate against their
1204  * own vnodes if they fail to implement VOP_PUTPAGES.
1205  *
1206  * This is typically called indirectly via the pageout daemon and
1207  * clustering has already typically occurred, so in general we ask the
1208  * underlying filesystem to write the data out asynchronously rather
1209  * then delayed.
1210  */
1211 int
1212 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1213     int flags, int *rtvals)
1214 {
1215         vm_object_t object;
1216         vm_page_t m;
1217         vm_ooffset_t maxblksz, next_offset, poffset, prev_offset;
1218         struct uio auio;
1219         struct iovec aiov;
1220         off_t prev_resid, wrsz;
1221         int count, error, i, maxsize, ncount, pgoff, ppscheck;
1222         bool in_hole;
1223         static struct timeval lastfail;
1224         static int curfail;
1225
1226         object = vp->v_object;
1227         count = bytecount / PAGE_SIZE;
1228
1229         for (i = 0; i < count; i++)
1230                 rtvals[i] = VM_PAGER_ERROR;
1231
1232         if ((int64_t)ma[0]->pindex < 0) {
1233                 printf("vnode_pager_generic_putpages: "
1234                     "attempt to write meta-data 0x%jx(%lx)\n",
1235                     (uintmax_t)ma[0]->pindex, (u_long)ma[0]->dirty);
1236                 rtvals[0] = VM_PAGER_BAD;
1237                 return (VM_PAGER_BAD);
1238         }
1239
1240         maxsize = count * PAGE_SIZE;
1241         ncount = count;
1242
1243         poffset = IDX_TO_OFF(ma[0]->pindex);
1244
1245         /*
1246          * If the page-aligned write is larger then the actual file we
1247          * have to invalidate pages occurring beyond the file EOF.  However,
1248          * there is an edge case where a file may not be page-aligned where
1249          * the last page is partially invalid.  In this case the filesystem
1250          * may not properly clear the dirty bits for the entire page (which
1251          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1252          * With the page locked we are free to fix-up the dirty bits here.
1253          *
1254          * We do not under any circumstances truncate the valid bits, as
1255          * this will screw up bogus page replacement.
1256          */
1257         VM_OBJECT_RLOCK(object);
1258         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1259                 if (!VM_OBJECT_TRYUPGRADE(object)) {
1260                         VM_OBJECT_RUNLOCK(object);
1261                         VM_OBJECT_WLOCK(object);
1262                         if (maxsize + poffset <= object->un_pager.vnp.vnp_size)
1263                                 goto downgrade;
1264                 }
1265                 if (object->un_pager.vnp.vnp_size > poffset) {
1266                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1267                         ncount = btoc(maxsize);
1268                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1269                                 pgoff = roundup2(pgoff, DEV_BSIZE);
1270
1271                                 /*
1272                                  * If the object is locked and the following
1273                                  * conditions hold, then the page's dirty
1274                                  * field cannot be concurrently changed by a
1275                                  * pmap operation.
1276                                  */
1277                                 m = ma[ncount - 1];
1278                                 vm_page_assert_sbusied(m);
1279                                 KASSERT(!pmap_page_is_write_mapped(m),
1280                 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1281                                 MPASS(m->dirty != 0);
1282                                 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1283                                     pgoff);
1284                         }
1285                 } else {
1286                         maxsize = 0;
1287                         ncount = 0;
1288                 }
1289                 for (i = ncount; i < count; i++)
1290                         rtvals[i] = VM_PAGER_BAD;
1291 downgrade:
1292                 VM_OBJECT_LOCK_DOWNGRADE(object);
1293         }
1294
1295         auio.uio_iov = &aiov;
1296         auio.uio_segflg = UIO_NOCOPY;
1297         auio.uio_rw = UIO_WRITE;
1298         auio.uio_td = NULL;
1299         maxblksz = roundup2(poffset + maxsize, DEV_BSIZE);
1300
1301         for (prev_offset = poffset; prev_offset < maxblksz;) {
1302                 /* Skip clean blocks. */
1303                 for (in_hole = true; in_hole && prev_offset < maxblksz;) {
1304                         m = ma[OFF_TO_IDX(prev_offset - poffset)];
1305                         for (i = vn_off2bidx(prev_offset);
1306                             i < sizeof(vm_page_bits_t) * NBBY &&
1307                             prev_offset < maxblksz; i++) {
1308                                 if (vn_dirty_blk(m, prev_offset)) {
1309                                         in_hole = false;
1310                                         break;
1311                                 }
1312                                 prev_offset += DEV_BSIZE;
1313                         }
1314                 }
1315                 if (in_hole)
1316                         goto write_done;
1317
1318                 /* Find longest run of dirty blocks. */
1319                 for (next_offset = prev_offset; next_offset < maxblksz;) {
1320                         m = ma[OFF_TO_IDX(next_offset - poffset)];
1321                         for (i = vn_off2bidx(next_offset);
1322                             i < sizeof(vm_page_bits_t) * NBBY &&
1323                             next_offset < maxblksz; i++) {
1324                                 if (!vn_dirty_blk(m, next_offset))
1325                                         goto start_write;
1326                                 next_offset += DEV_BSIZE;
1327                         }
1328                 }
1329 start_write:
1330                 if (next_offset > poffset + maxsize)
1331                         next_offset = poffset + maxsize;
1332
1333                 /*
1334                  * Getting here requires finding a dirty block in the
1335                  * 'skip clean blocks' loop.
1336                  */
1337                 MPASS(prev_offset < next_offset);
1338
1339                 VM_OBJECT_RUNLOCK(object);
1340                 aiov.iov_base = NULL;
1341                 auio.uio_iovcnt = 1;
1342                 auio.uio_offset = prev_offset;
1343                 prev_resid = auio.uio_resid = aiov.iov_len = next_offset -
1344                     prev_offset;
1345                 error = VOP_WRITE(vp, &auio,
1346                     vnode_pager_putpages_ioflags(flags), curthread->td_ucred);
1347
1348                 wrsz = prev_resid - auio.uio_resid;
1349                 if (wrsz == 0) {
1350                         if (ppsratecheck(&lastfail, &curfail, 1) != 0) {
1351                                 vn_printf(vp, "vnode_pager_putpages: "
1352                                     "zero-length write at %ju resid %zd\n",
1353                                     auio.uio_offset, auio.uio_resid);
1354                         }
1355                         VM_OBJECT_RLOCK(object);
1356                         break;
1357                 }
1358
1359                 /* Adjust the starting offset for next iteration. */
1360                 prev_offset += wrsz;
1361                 MPASS(auio.uio_offset == prev_offset);
1362
1363                 ppscheck = 0;
1364                 if (error != 0 && (ppscheck = ppsratecheck(&lastfail,
1365                     &curfail, 1)) != 0)
1366                         vn_printf(vp, "vnode_pager_putpages: I/O error %d\n",
1367                             error);
1368                 if (auio.uio_resid != 0 && (ppscheck != 0 ||
1369                     ppsratecheck(&lastfail, &curfail, 1) != 0))
1370                         vn_printf(vp, "vnode_pager_putpages: residual I/O %zd "
1371                             "at %ju\n", auio.uio_resid,
1372                             (uintmax_t)ma[0]->pindex);
1373                 VM_OBJECT_RLOCK(object);
1374                 if (error != 0 || auio.uio_resid != 0)
1375                         break;
1376         }
1377 write_done:
1378         /* Mark completely processed pages. */
1379         for (i = 0; i < OFF_TO_IDX(prev_offset - poffset); i++)
1380                 rtvals[i] = VM_PAGER_OK;
1381         /* Mark partial EOF page. */
1382         if (prev_offset == poffset + maxsize && (prev_offset & PAGE_MASK) != 0)
1383                 rtvals[i++] = VM_PAGER_OK;
1384         /* Unwritten pages in range, free bonus if the page is clean. */
1385         for (; i < ncount; i++)
1386                 rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR;
1387         VM_OBJECT_RUNLOCK(object);
1388         VM_CNT_ADD(v_vnodepgsout, i);
1389         VM_CNT_INC(v_vnodeout);
1390         return (rtvals[0]);
1391 }
1392
1393 int
1394 vnode_pager_putpages_ioflags(int pager_flags)
1395 {
1396         int ioflags;
1397
1398         /*
1399          * Pageouts are already clustered, use IO_ASYNC to force a
1400          * bawrite() rather then a bdwrite() to prevent paging I/O
1401          * from saturating the buffer cache.  Dummy-up the sequential
1402          * heuristic to cause large ranges to cluster.  If neither
1403          * IO_SYNC or IO_ASYNC is set, the system decides how to
1404          * cluster.
1405          */
1406         ioflags = IO_VMIO;
1407         if ((pager_flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) != 0)
1408                 ioflags |= IO_SYNC;
1409         else if ((pager_flags & VM_PAGER_CLUSTER_OK) == 0)
1410                 ioflags |= IO_ASYNC;
1411         ioflags |= (pager_flags & VM_PAGER_PUT_INVAL) != 0 ? IO_INVAL: 0;
1412         ioflags |= (pager_flags & VM_PAGER_PUT_NOREUSE) != 0 ? IO_NOREUSE : 0;
1413         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1414         return (ioflags);
1415 }
1416
1417 /*
1418  * vnode_pager_undirty_pages().
1419  *
1420  * A helper to mark pages as clean after pageout that was possibly
1421  * done with a short write.  The lpos argument specifies the page run
1422  * length in bytes, and the written argument specifies how many bytes
1423  * were actually written.  eof is the offset past the last valid byte
1424  * in the vnode using the absolute file position of the first byte in
1425  * the run as the base from which it is computed.
1426  */
1427 void
1428 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
1429     int lpos)
1430 {
1431         vm_object_t obj;
1432         int i, pos, pos_devb;
1433
1434         if (written == 0 && eof >= lpos)
1435                 return;
1436         obj = ma[0]->object;
1437         VM_OBJECT_WLOCK(obj);
1438         for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1439                 if (pos < trunc_page(written)) {
1440                         rtvals[i] = VM_PAGER_OK;
1441                         vm_page_undirty(ma[i]);
1442                 } else {
1443                         /* Partially written page. */
1444                         rtvals[i] = VM_PAGER_AGAIN;
1445                         vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1446                 }
1447         }
1448         if (eof >= lpos) /* avoid truncation */
1449                 goto done;
1450         for (pos = eof, i = OFF_TO_IDX(trunc_page(pos)); pos < lpos; i++) {
1451                 if (pos != trunc_page(pos)) {
1452                         /*
1453                          * The page contains the last valid byte in
1454                          * the vnode, mark the rest of the page as
1455                          * clean, potentially making the whole page
1456                          * clean.
1457                          */
1458                         pos_devb = roundup2(pos & PAGE_MASK, DEV_BSIZE);
1459                         vm_page_clear_dirty(ma[i], pos_devb, PAGE_SIZE -
1460                             pos_devb);
1461
1462                         /*
1463                          * If the page was cleaned, report the pageout
1464                          * on it as successful.  msync() no longer
1465                          * needs to write out the page, endlessly
1466                          * creating write requests and dirty buffers.
1467                          */
1468                         if (ma[i]->dirty == 0)
1469                                 rtvals[i] = VM_PAGER_OK;
1470
1471                         pos = round_page(pos);
1472                 } else {
1473                         /* vm_pageout_flush() clears dirty */
1474                         rtvals[i] = VM_PAGER_BAD;
1475                         pos += PAGE_SIZE;
1476                 }
1477         }
1478 done:
1479         VM_OBJECT_WUNLOCK(obj);
1480 }
1481
1482 void
1483 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1484     vm_offset_t end)
1485 {
1486         struct vnode *vp;
1487         vm_ooffset_t old_wm;
1488
1489         VM_OBJECT_WLOCK(object);
1490         if (object->type != OBJT_VNODE) {
1491                 VM_OBJECT_WUNLOCK(object);
1492                 return;
1493         }
1494         old_wm = object->un_pager.vnp.writemappings;
1495         object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1496         vp = object->handle;
1497         if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1498                 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1499                 VOP_ADD_WRITECOUNT(vp, 1);
1500                 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1501                     __func__, vp, vp->v_writecount);
1502         } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1503                 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1504                 VOP_ADD_WRITECOUNT(vp, -1);
1505                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1506                     __func__, vp, vp->v_writecount);
1507         }
1508         VM_OBJECT_WUNLOCK(object);
1509 }
1510
1511 void
1512 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1513     vm_offset_t end)
1514 {
1515         struct vnode *vp;
1516         struct mount *mp;
1517         vm_offset_t inc;
1518
1519         VM_OBJECT_WLOCK(object);
1520
1521         /*
1522          * First, recheck the object type to account for the race when
1523          * the vnode is reclaimed.
1524          */
1525         if (object->type != OBJT_VNODE) {
1526                 VM_OBJECT_WUNLOCK(object);
1527                 return;
1528         }
1529
1530         /*
1531          * Optimize for the case when writemappings is not going to
1532          * zero.
1533          */
1534         inc = end - start;
1535         if (object->un_pager.vnp.writemappings != inc) {
1536                 object->un_pager.vnp.writemappings -= inc;
1537                 VM_OBJECT_WUNLOCK(object);
1538                 return;
1539         }
1540
1541         vp = object->handle;
1542         vhold(vp);
1543         VM_OBJECT_WUNLOCK(object);
1544         mp = NULL;
1545         vn_start_write(vp, &mp, V_WAIT);
1546         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1547
1548         /*
1549          * Decrement the object's writemappings, by swapping the start
1550          * and end arguments for vnode_pager_update_writecount().  If
1551          * there was not a race with vnode reclaimation, then the
1552          * vnode's v_writecount is decremented.
1553          */
1554         vnode_pager_update_writecount(object, end, start);
1555         VOP_UNLOCK(vp, 0);
1556         vdrop(vp);
1557         if (mp != NULL)
1558                 vn_finished_write(mp);
1559 }