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/sysctl.h>
  63 #include <sys/proc.h>
  64 #include <sys/vnode.h>
  65 #include <sys/mount.h>
  66 #include <sys/bio.h>
  67 #include <sys/buf.h>
  68 #include <sys/vmmeter.h>
  69 #include <sys/limits.h>
  70 #include <sys/conf.h>
  71 #include <sys/rwlock.h>
  72 #include <sys/sf_buf.h>
  73 #include <sys/domainset.h>
  74
  75 #include <machine/atomic.h>
  76
  77 #include <vm/vm.h>
  78 #include <vm/vm_param.h>
  79 #include <vm/vm_object.h>
  80 #include <vm/vm_page.h>
  81 #include <vm/vm_pager.h>
  82 #include <vm/vm_map.h>
  83 #include <vm/vnode_pager.h>
  84 #include <vm/vm_extern.h>
  85
  86 static int vnode_pager_addr(struct vnode *vp, vm_ooffset_t address,
  87     daddr_t *rtaddress, int *run);
  88 static int vnode_pager_input_smlfs(vm_object_t object, vm_page_t m);
  89 static int vnode_pager_input_old(vm_object_t object, vm_page_t m);
  90 static void vnode_pager_dealloc(vm_object_t);
  91 static int vnode_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *);
  92 static int vnode_pager_getpages_async(vm_object_t, vm_page_t *, int, int *,
  93     int *, vop_getpages_iodone_t, void *);
  94 static void vnode_pager_putpages(vm_object_t, vm_page_t *, int, int, int *);
  95 static boolean_t vnode_pager_haspage(vm_object_t, vm_pindex_t, int *, int *);
  96 static vm_object_t vnode_pager_alloc(void *, vm_ooffset_t, vm_prot_t,
  97     vm_ooffset_t, struct ucred *cred);
  98 static int vnode_pager_generic_getpages_done(struct buf *);
  99 static void vnode_pager_generic_getpages_done_async(struct buf *);
 100
 101 struct pagerops vnodepagerops = {
 102         .pgo_alloc =    vnode_pager_alloc,
 103         .pgo_dealloc =  vnode_pager_dealloc,
 104         .pgo_getpages = vnode_pager_getpages,
 105         .pgo_getpages_async = vnode_pager_getpages_async,
 106         .pgo_putpages = vnode_pager_putpages,
 107         .pgo_haspage =  vnode_pager_haspage,
 108 };
 109
 110 int vnode_pbuf_freecnt;
 111 int vnode_async_pbuf_freecnt;
 112
 113 static struct domainset *vnode_domainset = NULL;
 114
 115 SYSCTL_PROC(_debug, OID_AUTO, vnode_domainset, CTLTYPE_STRING | CTLFLAG_RW,
 116     &vnode_domainset, 0, sysctl_handle_domainset, "A",
 117     "Default vnode NUMA policy");
 118
 119 /* Create the VM system backing object for this vnode */
 120 int
 121 vnode_create_vobject(struct vnode *vp, off_t isize, struct thread *td)
 122 {
 123         vm_object_t object;
 124         vm_ooffset_t size = isize;
 125         struct vattr va;
 126
 127         if (!vn_isdisk(vp, NULL) && vn_canvmio(vp) == FALSE)
 128                 return (0);
 129
 130         while ((object = vp->v_object) != NULL) {
 131                 VM_OBJECT_WLOCK(object);
 132                 if (!(object->flags & OBJ_DEAD)) {
 133                         VM_OBJECT_WUNLOCK(object);
 134                         return (0);
 135                 }
 136                 VOP_UNLOCK(vp, 0);
 137                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 138                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vodead", 0);
 139                 vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
 140         }
 141
 142         if (size == 0) {
 143                 if (vn_isdisk(vp, NULL)) {
 144                         size = IDX_TO_OFF(INT_MAX);
 145                 } else {
 146                         if (VOP_GETATTR(vp, &va, td->td_ucred))
 147                                 return (0);
 148                         size = va.va_size;
 149                 }
 150         }
 151
 152         object = vnode_pager_alloc(vp, size, 0, 0, td->td_ucred);
 153         /*
 154          * Dereference the reference we just created.  This assumes
 155          * that the object is associated with the vp.
 156          */
 157         VM_OBJECT_WLOCK(object);
 158         object->ref_count--;
 159         VM_OBJECT_WUNLOCK(object);
 160         vrele(vp);
 161
 162         KASSERT(vp->v_object != NULL, ("vnode_create_vobject: NULL object"));
 163
 164         return (0);
 165 }
 166
 167 void
 168 vnode_destroy_vobject(struct vnode *vp)
 169 {
 170         struct vm_object *obj;
 171
 172         obj = vp->v_object;
 173         if (obj == NULL)
 174                 return;
 175         ASSERT_VOP_ELOCKED(vp, "vnode_destroy_vobject");
 176         VM_OBJECT_WLOCK(obj);
 177         umtx_shm_object_terminated(obj);
 178         if (obj->ref_count == 0) {
 179                 /*
 180                  * don't double-terminate the object
 181                  */
 182                 if ((obj->flags & OBJ_DEAD) == 0) {
 183                         vm_object_terminate(obj);
 184                 } else {
 185                         /*
 186                          * Waiters were already handled during object
 187                          * termination.  The exclusive vnode lock hopefully
 188                          * prevented new waiters from referencing the dying
 189                          * object.
 190                          */
 191                         KASSERT((obj->flags & OBJ_DISCONNECTWNT) == 0,
 192                             ("OBJ_DISCONNECTWNT set obj %p flags %x",
 193                             obj, obj->flags));
 194                         vp->v_object = NULL;
 195                         VM_OBJECT_WUNLOCK(obj);
 196                 }
 197         } else {
 198                 /*
 199                  * Woe to the process that tries to page now :-).
 200                  */
 201                 vm_pager_deallocate(obj);
 202                 VM_OBJECT_WUNLOCK(obj);
 203         }
 204         KASSERT(vp->v_object == NULL, ("vp %p obj %p", vp, vp->v_object));
 205 }
 206
 207
 208 /*
 209  * Allocate (or lookup) pager for a vnode.
 210  * Handle is a vnode pointer.
 211  *
 212  * MPSAFE
 213  */
 214 vm_object_t
 215 vnode_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot,
 216     vm_ooffset_t offset, struct ucred *cred)
 217 {
 218         vm_object_t object;
 219         struct vnode *vp;
 220
 221         /*
 222          * Pageout to vnode, no can do yet.
 223          */
 224         if (handle == NULL)
 225                 return (NULL);
 226
 227         vp = (struct vnode *) handle;
 228
 229         /*
 230          * If the object is being terminated, wait for it to
 231          * go away.
 232          */
 233 retry:
 234         while ((object = vp->v_object) != NULL) {
 235                 VM_OBJECT_WLOCK(object);
 236                 if ((object->flags & OBJ_DEAD) == 0)
 237                         break;
 238                 vm_object_set_flag(object, OBJ_DISCONNECTWNT);
 239                 VM_OBJECT_SLEEP(object, object, PDROP | PVM, "vadead", 0);
 240         }
 241
 242         KASSERT(vp->v_usecount != 0, ("vnode_pager_alloc: no vnode reference"));
 243
 244         if (object == NULL) {
 245                 /*
 246                  * Add an object of the appropriate size
 247                  */
 248                 object = vm_object_allocate(OBJT_VNODE, OFF_TO_IDX(round_page(size)));
 249
 250                 object->un_pager.vnp.vnp_size = size;
 251                 object->un_pager.vnp.writemappings = 0;
 252                 object->domain.dr_policy = vnode_domainset;
 253
 254                 object->handle = handle;
 255                 VI_LOCK(vp);
 256                 if (vp->v_object != NULL) {
 257                         /*
 258                          * Object has been created while we were sleeping
 259                          */
 260                         VI_UNLOCK(vp);
 261                         VM_OBJECT_WLOCK(object);
 262                         KASSERT(object->ref_count == 1,
 263                             ("leaked ref %p %d", object, object->ref_count));
 264                         object->type = OBJT_DEAD;
 265                         object->ref_count = 0;
 266                         VM_OBJECT_WUNLOCK(object);
 267                         vm_object_destroy(object);
 268                         goto retry;
 269                 }
 270                 vp->v_object = object;
 271                 VI_UNLOCK(vp);
 272         } else {
 273                 object->ref_count++;
 274 #if VM_NRESERVLEVEL > 0
 275                 vm_object_color(object, 0);
 276 #endif
 277                 VM_OBJECT_WUNLOCK(object);
 278         }
 279         vrefact(vp);
 280         return (object);
 281 }
 282
 283 /*
 284  *      The object must be locked.
 285  */
 286 static void
 287 vnode_pager_dealloc(vm_object_t object)
 288 {
 289         struct vnode *vp;
 290         int refs;
 291
 292         vp = object->handle;
 293         if (vp == NULL)
 294                 panic("vnode_pager_dealloc: pager already dealloced");
 295
 296         VM_OBJECT_ASSERT_WLOCKED(object);
 297         vm_object_pip_wait(object, "vnpdea");
 298         refs = object->ref_count;
 299
 300         object->handle = NULL;
 301         object->type = OBJT_DEAD;
 302         if (object->flags & OBJ_DISCONNECTWNT) {
 303                 vm_object_clear_flag(object, OBJ_DISCONNECTWNT);
 304                 wakeup(object);
 305         }
 306         ASSERT_VOP_ELOCKED(vp, "vnode_pager_dealloc");
 307         if (object->un_pager.vnp.writemappings > 0) {
 308                 object->un_pager.vnp.writemappings = 0;
 309                 VOP_ADD_WRITECOUNT(vp, -1);
 310                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
 311                     __func__, vp, vp->v_writecount);
 312         }
 313         vp->v_object = NULL;
 314         VOP_UNSET_TEXT(vp);
 315         VM_OBJECT_WUNLOCK(object);
 316         while (refs-- > 0)
 317                 vunref(vp);
 318         VM_OBJECT_WLOCK(object);
 319 }
 320
 321 static boolean_t
 322 vnode_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *before,
 323     int *after)
 324 {
 325         struct vnode *vp = object->handle;
 326         daddr_t bn;
 327         int err;
 328         daddr_t reqblock;
 329         int poff;
 330         int bsize;
 331         int pagesperblock, blocksperpage;
 332
 333         VM_OBJECT_ASSERT_WLOCKED(object);
 334         /*
 335          * If no vp or vp is doomed or marked transparent to VM, we do not
 336          * have the page.
 337          */
 338         if (vp == NULL || vp->v_iflag & VI_DOOMED)
 339                 return FALSE;
 340         /*
 341          * If the offset is beyond end of file we do
 342          * not have the page.
 343          */
 344         if (IDX_TO_OFF(pindex) >= object->un_pager.vnp.vnp_size)
 345                 return FALSE;
 346
 347         bsize = vp->v_mount->mnt_stat.f_iosize;
 348         pagesperblock = bsize / PAGE_SIZE;
 349         blocksperpage = 0;
 350         if (pagesperblock > 0) {
 351                 reqblock = pindex / pagesperblock;
 352         } else {
 353                 blocksperpage = (PAGE_SIZE / bsize);
 354                 reqblock = pindex * blocksperpage;
 355         }
 356         VM_OBJECT_WUNLOCK(object);
 357         err = VOP_BMAP(vp, reqblock, NULL, &bn, after, before);
 358         VM_OBJECT_WLOCK(object);
 359         if (err)
 360                 return TRUE;
 361         if (bn == -1)
 362                 return FALSE;
 363         if (pagesperblock > 0) {
 364                 poff = pindex - (reqblock * pagesperblock);
 365                 if (before) {
 366                         *before *= pagesperblock;
 367                         *before += poff;
 368                 }
 369                 if (after) {
 370                         /*
 371                          * The BMAP vop can report a partial block in the
 372                          * 'after', but must not report blocks after EOF.
 373                          * Assert the latter, and truncate 'after' in case
 374                          * of the former.
 375                          */
 376                         KASSERT((reqblock + *after) * pagesperblock <
 377                             roundup2(object->size, pagesperblock),
 378                             ("%s: reqblock %jd after %d size %ju", __func__,
 379                             (intmax_t )reqblock, *after,
 380                             (uintmax_t )object->size));
 381                         *after *= pagesperblock;
 382                         *after += pagesperblock - (poff + 1);
 383                         if (pindex + *after >= object->size)
 384                                 *after = object->size - 1 - pindex;
 385                 }
 386         } else {
 387                 if (before) {
 388                         *before /= blocksperpage;
 389                 }
 390
 391                 if (after) {
 392                         *after /= blocksperpage;
 393                 }
 394         }
 395         return TRUE;
 396 }
 397
 398 /*
 399  * Lets the VM system know about a change in size for a file.
 400  * We adjust our own internal size and flush any cached pages in
 401  * the associated object that are affected by the size change.
 402  *
 403  * Note: this routine may be invoked as a result of a pager put
 404  * operation (possibly at object termination time), so we must be careful.
 405  */
 406 void
 407 vnode_pager_setsize(struct vnode *vp, vm_ooffset_t nsize)
 408 {
 409         vm_object_t object;
 410         vm_page_t m;
 411         vm_pindex_t nobjsize;
 412
 413         if ((object = vp->v_object) == NULL)
 414                 return;
 415 /*      ASSERT_VOP_ELOCKED(vp, "vnode_pager_setsize and not locked vnode"); */
 416         VM_OBJECT_WLOCK(object);
 417         if (object->type == OBJT_DEAD) {
 418                 VM_OBJECT_WUNLOCK(object);
 419                 return;
 420         }
 421         KASSERT(object->type == OBJT_VNODE,
 422             ("not vnode-backed object %p", object));
 423         if (nsize == object->un_pager.vnp.vnp_size) {
 424                 /*
 425                  * Hasn't changed size
 426                  */
 427                 VM_OBJECT_WUNLOCK(object);
 428                 return;
 429         }
 430         nobjsize = OFF_TO_IDX(nsize + PAGE_MASK);
 431         if (nsize < object->un_pager.vnp.vnp_size) {
 432                 /*
 433                  * File has shrunk. Toss any cached pages beyond the new EOF.
 434                  */
 435                 if (nobjsize < object->size)
 436                         vm_object_page_remove(object, nobjsize, object->size,
 437                             0);
 438                 /*
 439                  * this gets rid of garbage at the end of a page that is now
 440                  * only partially backed by the vnode.
 441                  *
 442                  * XXX for some reason (I don't know yet), if we take a
 443                  * completely invalid page and mark it partially valid
 444                  * it can screw up NFS reads, so we don't allow the case.
 445                  */
 446                 if ((nsize & PAGE_MASK) &&
 447                     (m = vm_page_lookup(object, OFF_TO_IDX(nsize))) != NULL &&
 448                     m->valid != 0) {
 449                         int base = (int)nsize & PAGE_MASK;
 450                         int size = PAGE_SIZE - base;
 451
 452                         /*
 453                          * Clear out partial-page garbage in case
 454                          * the page has been mapped.
 455                          */
 456                         pmap_zero_page_area(m, base, size);
 457
 458                         /*
 459                          * Update the valid bits to reflect the blocks that
 460                          * have been zeroed.  Some of these valid bits may
 461                          * have already been set.
 462                          */
 463                         vm_page_set_valid_range(m, base, size);
 464
 465                         /*
 466                          * Round "base" to the next block boundary so that the
 467                          * dirty bit for a partially zeroed block is not
 468                          * cleared.
 469                          */
 470                         base = roundup2(base, DEV_BSIZE);
 471
 472                         /*
 473                          * Clear out partial-page dirty bits.
 474                          *
 475                          * note that we do not clear out the valid
 476                          * bits.  This would prevent bogus_page
 477                          * replacement from working properly.
 478                          */
 479                         vm_page_clear_dirty(m, base, PAGE_SIZE - base);
 480                 }
 481         }
 482         object->un_pager.vnp.vnp_size = nsize;
 483         object->size = nobjsize;
 484         VM_OBJECT_WUNLOCK(object);
 485 }
 486
 487 /*
 488  * calculate the linear (byte) disk address of specified virtual
 489  * file address
 490  */
 491 static int
 492 vnode_pager_addr(struct vnode *vp, vm_ooffset_t address, daddr_t *rtaddress,
 493     int *run)
 494 {
 495         int bsize;
 496         int err;
 497         daddr_t vblock;
 498         daddr_t voffset;
 499
 500         if (address < 0)
 501                 return -1;
 502
 503         if (vp->v_iflag & VI_DOOMED)
 504                 return -1;
 505
 506         bsize = vp->v_mount->mnt_stat.f_iosize;
 507         vblock = address / bsize;
 508         voffset = address % bsize;
 509
 510         err = VOP_BMAP(vp, vblock, NULL, rtaddress, run, NULL);
 511         if (err == 0) {
 512                 if (*rtaddress != -1)
 513                         *rtaddress += voffset / DEV_BSIZE;
 514                 if (run) {
 515                         *run += 1;
 516                         *run *= bsize/PAGE_SIZE;
 517                         *run -= voffset/PAGE_SIZE;
 518                 }
 519         }
 520
 521         return (err);
 522 }
 523
 524 /*
 525  * small block filesystem vnode pager input
 526  */
 527 static int
 528 vnode_pager_input_smlfs(vm_object_t object, vm_page_t m)
 529 {
 530         struct vnode *vp;
 531         struct bufobj *bo;
 532         struct buf *bp;
 533         struct sf_buf *sf;
 534         daddr_t fileaddr;
 535         vm_offset_t bsize;
 536         vm_page_bits_t bits;
 537         int error, i;
 538
 539         error = 0;
 540         vp = object->handle;
 541         if (vp->v_iflag & VI_DOOMED)
 542                 return VM_PAGER_BAD;
 543
 544         bsize = vp->v_mount->mnt_stat.f_iosize;
 545
 546         VOP_BMAP(vp, 0, &bo, 0, NULL, NULL);
 547
 548         sf = sf_buf_alloc(m, 0);
 549
 550         for (i = 0; i < PAGE_SIZE / bsize; i++) {
 551                 vm_ooffset_t address;
 552
 553                 bits = vm_page_bits(i * bsize, bsize);
 554                 if (m->valid & bits)
 555                         continue;
 556
 557                 address = IDX_TO_OFF(m->pindex) + i * bsize;
 558                 if (address >= object->un_pager.vnp.vnp_size) {
 559                         fileaddr = -1;
 560                 } else {
 561                         error = vnode_pager_addr(vp, address, &fileaddr, NULL);
 562                         if (error)
 563                                 break;
 564                 }
 565                 if (fileaddr != -1) {
 566                         bp = getpbuf(&vnode_pbuf_freecnt);
 567
 568                         /* build a minimal buffer header */
 569                         bp->b_iocmd = BIO_READ;
 570                         bp->b_iodone = bdone;
 571                         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
 572                         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
 573                         bp->b_rcred = crhold(curthread->td_ucred);
 574                         bp->b_wcred = crhold(curthread->td_ucred);
 575                         bp->b_data = (caddr_t)sf_buf_kva(sf) + i * bsize;
 576                         bp->b_blkno = fileaddr;
 577                         pbgetbo(bo, bp);
 578                         bp->b_vp = vp;
 579                         bp->b_bcount = bsize;
 580                         bp->b_bufsize = bsize;
 581                         bp->b_runningbufspace = bp->b_bufsize;
 582                         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
 583
 584                         /* do the input */
 585                         bp->b_iooffset = dbtob(bp->b_blkno);
 586                         bstrategy(bp);
 587
 588                         bwait(bp, PVM, "vnsrd");
 589
 590                         if ((bp->b_ioflags & BIO_ERROR) != 0)
 591                                 error = EIO;
 592
 593                         /*
 594                          * free the buffer header back to the swap buffer pool
 595                          */
 596                         bp->b_vp = NULL;
 597                         pbrelbo(bp);
 598                         relpbuf(bp, &vnode_pbuf_freecnt);
 599                         if (error)
 600                                 break;
 601                 } else
 602                         bzero((caddr_t)sf_buf_kva(sf) + i * bsize, bsize);
 603                 KASSERT((m->dirty & bits) == 0,
 604                     ("vnode_pager_input_smlfs: page %p is dirty", m));
 605                 VM_OBJECT_WLOCK(object);
 606                 m->valid |= bits;
 607                 VM_OBJECT_WUNLOCK(object);
 608         }
 609         sf_buf_free(sf);
 610         if (error) {
 611                 return VM_PAGER_ERROR;
 612         }
 613         return VM_PAGER_OK;
 614 }
 615
 616 /*
 617  * old style vnode pager input routine
 618  */
 619 static int
 620 vnode_pager_input_old(vm_object_t object, vm_page_t m)
 621 {
 622         struct uio auio;
 623         struct iovec aiov;
 624         int error;
 625         int size;
 626         struct sf_buf *sf;
 627         struct vnode *vp;
 628
 629         VM_OBJECT_ASSERT_WLOCKED(object);
 630         error = 0;
 631
 632         /*
 633          * Return failure if beyond current EOF
 634          */
 635         if (IDX_TO_OFF(m->pindex) >= object->un_pager.vnp.vnp_size) {
 636                 return VM_PAGER_BAD;
 637         } else {
 638                 size = PAGE_SIZE;
 639                 if (IDX_TO_OFF(m->pindex) + size > object->un_pager.vnp.vnp_size)
 640                         size = object->un_pager.vnp.vnp_size - IDX_TO_OFF(m->pindex);
 641                 vp = object->handle;
 642                 VM_OBJECT_WUNLOCK(object);
 643
 644                 /*
 645                  * Allocate a kernel virtual address and initialize so that
 646                  * we can use VOP_READ/WRITE routines.
 647                  */
 648                 sf = sf_buf_alloc(m, 0);
 649
 650                 aiov.iov_base = (caddr_t)sf_buf_kva(sf);
 651                 aiov.iov_len = size;
 652                 auio.uio_iov = &aiov;
 653                 auio.uio_iovcnt = 1;
 654                 auio.uio_offset = IDX_TO_OFF(m->pindex);
 655                 auio.uio_segflg = UIO_SYSSPACE;
 656                 auio.uio_rw = UIO_READ;
 657                 auio.uio_resid = size;
 658                 auio.uio_td = curthread;
 659
 660                 error = VOP_READ(vp, &auio, 0, curthread->td_ucred);
 661                 if (!error) {
 662                         int count = size - auio.uio_resid;
 663
 664                         if (count == 0)
 665                                 error = EINVAL;
 666                         else if (count != PAGE_SIZE)
 667                                 bzero((caddr_t)sf_buf_kva(sf) + count,
 668                                     PAGE_SIZE - count);
 669                 }
 670                 sf_buf_free(sf);
 671
 672                 VM_OBJECT_WLOCK(object);
 673         }
 674         KASSERT(m->dirty == 0, ("vnode_pager_input_old: page %p is dirty", m));
 675         if (!error)
 676                 m->valid = VM_PAGE_BITS_ALL;
 677         return error ? VM_PAGER_ERROR : VM_PAGER_OK;
 678 }
 679
 680 /*
 681  * generic vnode pager input routine
 682  */
 683
 684 /*
 685  * Local media VFS's that do not implement their own VOP_GETPAGES
 686  * should have their VOP_GETPAGES call to vnode_pager_generic_getpages()
 687  * to implement the previous behaviour.
 688  *
 689  * All other FS's should use the bypass to get to the local media
 690  * backing vp's VOP_GETPAGES.
 691  */
 692 static int
 693 vnode_pager_getpages(vm_object_t object, vm_page_t *m, int count, int *rbehind,
 694     int *rahead)
 695 {
 696         struct vnode *vp;
 697         int rtval;
 698
 699         vp = object->handle;
 700         VM_OBJECT_WUNLOCK(object);
 701         rtval = VOP_GETPAGES(vp, m, count, rbehind, rahead);
 702         KASSERT(rtval != EOPNOTSUPP,
 703             ("vnode_pager: FS getpages not implemented\n"));
 704         VM_OBJECT_WLOCK(object);
 705         return rtval;
 706 }
 707
 708 static int
 709 vnode_pager_getpages_async(vm_object_t object, vm_page_t *m, int count,
 710     int *rbehind, int *rahead, vop_getpages_iodone_t iodone, void *arg)
 711 {
 712         struct vnode *vp;
 713         int rtval;
 714
 715         vp = object->handle;
 716         VM_OBJECT_WUNLOCK(object);
 717         rtval = VOP_GETPAGES_ASYNC(vp, m, count, rbehind, rahead, iodone, arg);
 718         KASSERT(rtval != EOPNOTSUPP,
 719             ("vnode_pager: FS getpages_async not implemented\n"));
 720         VM_OBJECT_WLOCK(object);
 721         return (rtval);
 722 }
 723
 724 /*
 725  * The implementation of VOP_GETPAGES() and VOP_GETPAGES_ASYNC() for
 726  * local filesystems, where partially valid pages can only occur at
 727  * the end of file.
 728  */
 729 int
 730 vnode_pager_local_getpages(struct vop_getpages_args *ap)
 731 {
 732
 733         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 734             ap->a_rbehind, ap->a_rahead, NULL, NULL));
 735 }
 736
 737 int
 738 vnode_pager_local_getpages_async(struct vop_getpages_async_args *ap)
 739 {
 740
 741         return (vnode_pager_generic_getpages(ap->a_vp, ap->a_m, ap->a_count,
 742             ap->a_rbehind, ap->a_rahead, ap->a_iodone, ap->a_arg));
 743 }
 744
 745 /*
 746  * This is now called from local media FS's to operate against their
 747  * own vnodes if they fail to implement VOP_GETPAGES.
 748  */
 749 int
 750 vnode_pager_generic_getpages(struct vnode *vp, vm_page_t *m, int count,
 751     int *a_rbehind, int *a_rahead, vop_getpages_iodone_t iodone, void *arg)
 752 {
 753         vm_object_t object;
 754         struct bufobj *bo;
 755         struct buf *bp;
 756         off_t foff;
 757 #ifdef INVARIANTS
 758         off_t blkno0;
 759 #endif
 760         int bsize, pagesperblock, *freecnt;
 761         int error, before, after, rbehind, rahead, poff, i;
 762         int bytecount, secmask;
 763
 764         KASSERT(vp->v_type != VCHR && vp->v_type != VBLK,
 765             ("%s does not support devices", __func__));
 766
 767         if (vp->v_iflag & VI_DOOMED)
 768                 return (VM_PAGER_BAD);
 769
 770         object = vp->v_object;
 771         foff = IDX_TO_OFF(m[0]->pindex);
 772         bsize = vp->v_mount->mnt_stat.f_iosize;
 773         pagesperblock = bsize / PAGE_SIZE;
 774
 775         KASSERT(foff < object->un_pager.vnp.vnp_size,
 776             ("%s: page %p offset beyond vp %p size", __func__, m[0], vp));
 777         KASSERT(count <= sizeof(bp->b_pages),
 778             ("%s: requested %d pages", __func__, count));
 779
 780         /*
 781          * The last page has valid blocks.  Invalid part can only
 782          * exist at the end of file, and the page is made fully valid
 783          * by zeroing in vm_pager_get_pages().
 784          */
 785         if (m[count - 1]->valid != 0 && --count == 0) {
 786                 if (iodone != NULL)
 787                         iodone(arg, m, 1, 0);
 788                 return (VM_PAGER_OK);
 789         }
 790
 791         /*
 792          * Synchronous and asynchronous paging operations use different
 793          * free pbuf counters.  This is done to avoid asynchronous requests
 794          * to consume all pbufs.
 795          * Allocate the pbuf at the very beginning of the function, so that
 796          * if we are low on certain kind of pbufs don't even proceed to BMAP,
 797          * but sleep.
 798          */
 799         freecnt = iodone != NULL ?
 800             &vnode_async_pbuf_freecnt : &vnode_pbuf_freecnt;
 801         bp = getpbuf(freecnt);
 802
 803         /*
 804          * Get the underlying device blocks for the file with VOP_BMAP().
 805          * If the file system doesn't support VOP_BMAP, use old way of
 806          * getting pages via VOP_READ.
 807          */
 808         error = VOP_BMAP(vp, foff / bsize, &bo, &bp->b_blkno, &after, &before);
 809         if (error == EOPNOTSUPP) {
 810                 relpbuf(bp, freecnt);
 811                 VM_OBJECT_WLOCK(object);
 812                 for (i = 0; i < count; i++) {
 813                         VM_CNT_INC(v_vnodein);
 814                         VM_CNT_INC(v_vnodepgsin);
 815                         error = vnode_pager_input_old(object, m[i]);
 816                         if (error)
 817                                 break;
 818                 }
 819                 VM_OBJECT_WUNLOCK(object);
 820                 return (error);
 821         } else if (error != 0) {
 822                 relpbuf(bp, freecnt);
 823                 return (VM_PAGER_ERROR);
 824         }
 825
 826         /*
 827          * If the file system supports BMAP, but blocksize is smaller
 828          * than a page size, then use special small filesystem code.
 829          */
 830         if (pagesperblock == 0) {
 831                 relpbuf(bp, freecnt);
 832                 for (i = 0; i < count; i++) {
 833                         VM_CNT_INC(v_vnodein);
 834                         VM_CNT_INC(v_vnodepgsin);
 835                         error = vnode_pager_input_smlfs(object, m[i]);
 836                         if (error)
 837                                 break;
 838                 }
 839                 return (error);
 840         }
 841
 842         /*
 843          * A sparse file can be encountered only for a single page request,
 844          * which may not be preceded by call to vm_pager_haspage().
 845          */
 846         if (bp->b_blkno == -1) {
 847                 KASSERT(count == 1,
 848                     ("%s: array[%d] request to a sparse file %p", __func__,
 849                     count, vp));
 850                 relpbuf(bp, freecnt);
 851                 pmap_zero_page(m[0]);
 852                 KASSERT(m[0]->dirty == 0, ("%s: page %p is dirty",
 853                     __func__, m[0]));
 854                 VM_OBJECT_WLOCK(object);
 855                 m[0]->valid = VM_PAGE_BITS_ALL;
 856                 VM_OBJECT_WUNLOCK(object);
 857                 return (VM_PAGER_OK);
 858         }
 859
 860 #ifdef INVARIANTS
 861         blkno0 = bp->b_blkno;
 862 #endif
 863         bp->b_blkno += (foff % bsize) / DEV_BSIZE;
 864
 865         /* Recalculate blocks available after/before to pages. */
 866         poff = (foff % bsize) / PAGE_SIZE;
 867         before *= pagesperblock;
 868         before += poff;
 869         after *= pagesperblock;
 870         after += pagesperblock - (poff + 1);
 871         if (m[0]->pindex + after >= object->size)
 872                 after = object->size - 1 - m[0]->pindex;
 873         KASSERT(count <= after + 1, ("%s: %d pages asked, can do only %d",
 874             __func__, count, after + 1));
 875         after -= count - 1;
 876
 877         /* Trim requested rbehind/rahead to possible values. */
 878         rbehind = a_rbehind ? *a_rbehind : 0;
 879         rahead = a_rahead ? *a_rahead : 0;
 880         rbehind = min(rbehind, before);
 881         rbehind = min(rbehind, m[0]->pindex);
 882         rahead = min(rahead, after);
 883         rahead = min(rahead, object->size - m[count - 1]->pindex);
 884         /*
 885          * Check that total amount of pages fit into buf.  Trim rbehind and
 886          * rahead evenly if not.
 887          */
 888         if (rbehind + rahead + count > nitems(bp->b_pages)) {
 889                 int trim, sum;
 890
 891                 trim = rbehind + rahead + count - nitems(bp->b_pages) + 1;
 892                 sum = rbehind + rahead;
 893                 if (rbehind == before) {
 894                         /* Roundup rbehind trim to block size. */
 895                         rbehind -= roundup(trim * rbehind / sum, pagesperblock);
 896                         if (rbehind < 0)
 897                                 rbehind = 0;
 898                 } else
 899                         rbehind -= trim * rbehind / sum;
 900                 rahead -= trim * rahead / sum;
 901         }
 902         KASSERT(rbehind + rahead + count <= nitems(bp->b_pages),
 903             ("%s: behind %d ahead %d count %d", __func__,
 904             rbehind, rahead, count));
 905
 906         /*
 907          * Fill in the bp->b_pages[] array with requested and optional
 908          * read behind or read ahead pages.  Read behind pages are looked
 909          * up in a backward direction, down to a first cached page.  Same
 910          * for read ahead pages, but there is no need to shift the array
 911          * in case of encountering a cached page.
 912          */
 913         i = bp->b_npages = 0;
 914         if (rbehind) {
 915                 vm_pindex_t startpindex, tpindex;
 916                 vm_page_t p;
 917
 918                 VM_OBJECT_WLOCK(object);
 919                 startpindex = m[0]->pindex - rbehind;
 920                 if ((p = TAILQ_PREV(m[0], pglist, listq)) != NULL &&
 921                     p->pindex >= startpindex)
 922                         startpindex = p->pindex + 1;
 923
 924                 /* tpindex is unsigned; beware of numeric underflow. */
 925                 for (tpindex = m[0]->pindex - 1;
 926                     tpindex >= startpindex && tpindex < m[0]->pindex;
 927                     tpindex--, i++) {
 928                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
 929                         if (p == NULL) {
 930                                 /* Shift the array. */
 931                                 for (int j = 0; j < i; j++)
 932                                         bp->b_pages[j] = bp->b_pages[j +
 933                                             tpindex + 1 - startpindex];
 934                                 break;
 935                         }
 936                         bp->b_pages[tpindex - startpindex] = p;
 937                 }
 938
 939                 bp->b_pgbefore = i;
 940                 bp->b_npages += i;
 941                 bp->b_blkno -= IDX_TO_OFF(i) / DEV_BSIZE;
 942         } else
 943                 bp->b_pgbefore = 0;
 944
 945         /* Requested pages. */
 946         for (int j = 0; j < count; j++, i++)
 947                 bp->b_pages[i] = m[j];
 948         bp->b_npages += count;
 949
 950         if (rahead) {
 951                 vm_pindex_t endpindex, tpindex;
 952                 vm_page_t p;
 953
 954                 if (!VM_OBJECT_WOWNED(object))
 955                         VM_OBJECT_WLOCK(object);
 956                 endpindex = m[count - 1]->pindex + rahead + 1;
 957                 if ((p = TAILQ_NEXT(m[count - 1], listq)) != NULL &&
 958                     p->pindex < endpindex)
 959                         endpindex = p->pindex;
 960                 if (endpindex > object->size)
 961                         endpindex = object->size;
 962
 963                 for (tpindex = m[count - 1]->pindex + 1;
 964                     tpindex < endpindex; i++, tpindex++) {
 965                         p = vm_page_alloc(object, tpindex, VM_ALLOC_NORMAL);
 966                         if (p == NULL)
 967                                 break;
 968                         bp->b_pages[i] = p;
 969                 }
 970
 971                 bp->b_pgafter = i - bp->b_npages;
 972                 bp->b_npages = i;
 973         } else
 974                 bp->b_pgafter = 0;
 975
 976         if (VM_OBJECT_WOWNED(object))
 977                 VM_OBJECT_WUNLOCK(object);
 978
 979         /* Report back actual behind/ahead read. */
 980         if (a_rbehind)
 981                 *a_rbehind = bp->b_pgbefore;
 982         if (a_rahead)
 983                 *a_rahead = bp->b_pgafter;
 984
 985 #ifdef INVARIANTS
 986         KASSERT(bp->b_npages <= nitems(bp->b_pages),
 987             ("%s: buf %p overflowed", __func__, bp));
 988         for (int j = 1, prev = 0; j < bp->b_npages; j++) {
 989                 if (bp->b_pages[j] == bogus_page)
 990                         continue;
 991                 KASSERT(bp->b_pages[j]->pindex - bp->b_pages[prev]->pindex ==
 992                     j - prev, ("%s: pages array not consecutive, bp %p",
 993                      __func__, bp));
 994                 prev = j;
 995         }
 996 #endif
 997
 998         /*
 999          * Recalculate first offset and bytecount with regards to read behind.
1000          * Truncate bytecount to vnode real size and round up physical size
1001          * for real devices.
1002          */
1003         foff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1004         bytecount = bp->b_npages << PAGE_SHIFT;
1005         if ((foff + bytecount) > object->un_pager.vnp.vnp_size)
1006                 bytecount = object->un_pager.vnp.vnp_size - foff;
1007         secmask = bo->bo_bsize - 1;
1008         KASSERT(secmask < PAGE_SIZE && secmask > 0,
1009             ("%s: sector size %d too large", __func__, secmask + 1));
1010         bytecount = (bytecount + secmask) & ~secmask;
1011
1012         /*
1013          * And map the pages to be read into the kva, if the filesystem
1014          * requires mapped buffers.
1015          */
1016         if ((vp->v_mount->mnt_kern_flag & MNTK_UNMAPPED_BUFS) != 0 &&
1017             unmapped_buf_allowed) {
1018                 bp->b_data = unmapped_buf;
1019                 bp->b_offset = 0;
1020         } else {
1021                 bp->b_data = bp->b_kvabase;
1022                 pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages, bp->b_npages);
1023         }
1024
1025         /* Build a minimal buffer header. */
1026         bp->b_iocmd = BIO_READ;
1027         KASSERT(bp->b_rcred == NOCRED, ("leaking read ucred"));
1028         KASSERT(bp->b_wcred == NOCRED, ("leaking write ucred"));
1029         bp->b_rcred = crhold(curthread->td_ucred);
1030         bp->b_wcred = crhold(curthread->td_ucred);
1031         pbgetbo(bo, bp);
1032         bp->b_vp = vp;
1033         bp->b_bcount = bp->b_bufsize = bp->b_runningbufspace = bytecount;
1034         bp->b_iooffset = dbtob(bp->b_blkno);
1035         KASSERT(IDX_TO_OFF(m[0]->pindex - bp->b_pages[0]->pindex) ==
1036             (blkno0 - bp->b_blkno) * DEV_BSIZE +
1037             IDX_TO_OFF(m[0]->pindex) % bsize,
1038             ("wrong offsets bsize %d m[0] %ju b_pages[0] %ju "
1039             "blkno0 %ju b_blkno %ju", bsize,
1040             (uintmax_t)m[0]->pindex, (uintmax_t)bp->b_pages[0]->pindex,
1041             (uintmax_t)blkno0, (uintmax_t)bp->b_blkno));
1042
1043         atomic_add_long(&runningbufspace, bp->b_runningbufspace);
1044         VM_CNT_INC(v_vnodein);
1045         VM_CNT_ADD(v_vnodepgsin, bp->b_npages);
1046
1047         if (iodone != NULL) { /* async */
1048                 bp->b_pgiodone = iodone;
1049                 bp->b_caller1 = arg;
1050                 bp->b_iodone = vnode_pager_generic_getpages_done_async;
1051                 bp->b_flags |= B_ASYNC;
1052                 BUF_KERNPROC(bp);
1053                 bstrategy(bp);
1054                 return (VM_PAGER_OK);
1055         } else {
1056                 bp->b_iodone = bdone;
1057                 bstrategy(bp);
1058                 bwait(bp, PVM, "vnread");
1059                 error = vnode_pager_generic_getpages_done(bp);
1060                 for (i = 0; i < bp->b_npages; i++)
1061                         bp->b_pages[i] = NULL;
1062                 bp->b_vp = NULL;
1063                 pbrelbo(bp);
1064                 relpbuf(bp, &vnode_pbuf_freecnt);
1065                 return (error != 0 ? VM_PAGER_ERROR : VM_PAGER_OK);
1066         }
1067 }
1068
1069 static void
1070 vnode_pager_generic_getpages_done_async(struct buf *bp)
1071 {
1072         int error;
1073
1074         error = vnode_pager_generic_getpages_done(bp);
1075         /* Run the iodone upon the requested range. */
1076         bp->b_pgiodone(bp->b_caller1, bp->b_pages + bp->b_pgbefore,
1077             bp->b_npages - bp->b_pgbefore - bp->b_pgafter, error);
1078         for (int i = 0; i < bp->b_npages; i++)
1079                 bp->b_pages[i] = NULL;
1080         bp->b_vp = NULL;
1081         pbrelbo(bp);
1082         relpbuf(bp, &vnode_async_pbuf_freecnt);
1083 }
1084
1085 static int
1086 vnode_pager_generic_getpages_done(struct buf *bp)
1087 {
1088         vm_object_t object;
1089         off_t tfoff, nextoff;
1090         int i, error;
1091
1092         error = (bp->b_ioflags & BIO_ERROR) != 0 ? EIO : 0;
1093         object = bp->b_vp->v_object;
1094
1095         if (error == 0 && bp->b_bcount != bp->b_npages * PAGE_SIZE) {
1096                 if (!buf_mapped(bp)) {
1097                         bp->b_data = bp->b_kvabase;
1098                         pmap_qenter((vm_offset_t)bp->b_data, bp->b_pages,
1099                             bp->b_npages);
1100                 }
1101                 bzero(bp->b_data + bp->b_bcount,
1102                     PAGE_SIZE * bp->b_npages - bp->b_bcount);
1103         }
1104         if (buf_mapped(bp)) {
1105                 pmap_qremove((vm_offset_t)bp->b_data, bp->b_npages);
1106                 bp->b_data = unmapped_buf;
1107         }
1108
1109         VM_OBJECT_WLOCK(object);
1110         for (i = 0, tfoff = IDX_TO_OFF(bp->b_pages[0]->pindex);
1111             i < bp->b_npages; i++, tfoff = nextoff) {
1112                 vm_page_t mt;
1113
1114                 nextoff = tfoff + PAGE_SIZE;
1115                 mt = bp->b_pages[i];
1116
1117                 if (nextoff <= object->un_pager.vnp.vnp_size) {
1118                         /*
1119                          * Read filled up entire page.
1120                          */
1121                         mt->valid = VM_PAGE_BITS_ALL;
1122                         KASSERT(mt->dirty == 0,
1123                             ("%s: page %p is dirty", __func__, mt));
1124                         KASSERT(!pmap_page_is_mapped(mt),
1125                             ("%s: page %p is mapped", __func__, mt));
1126                 } else {
1127                         /*
1128                          * Read did not fill up entire page.
1129                          *
1130                          * Currently we do not set the entire page valid,
1131                          * we just try to clear the piece that we couldn't
1132                          * read.
1133                          */
1134                         vm_page_set_valid_range(mt, 0,
1135                             object->un_pager.vnp.vnp_size - tfoff);
1136                         KASSERT((mt->dirty & vm_page_bits(0,
1137                             object->un_pager.vnp.vnp_size - tfoff)) == 0,
1138                             ("%s: page %p is dirty", __func__, mt));
1139                 }
1140
1141                 if (i < bp->b_pgbefore || i >= bp->b_npages - bp->b_pgafter)
1142                         vm_page_readahead_finish(mt);
1143         }
1144         VM_OBJECT_WUNLOCK(object);
1145         if (error != 0)
1146                 printf("%s: I/O read error %d\n", __func__, error);
1147
1148         return (error);
1149 }
1150
1151 /*
1152  * EOPNOTSUPP is no longer legal.  For local media VFS's that do not
1153  * implement their own VOP_PUTPAGES, their VOP_PUTPAGES should call to
1154  * vnode_pager_generic_putpages() to implement the previous behaviour.
1155  *
1156  * All other FS's should use the bypass to get to the local media
1157  * backing vp's VOP_PUTPAGES.
1158  */
1159 static void
1160 vnode_pager_putpages(vm_object_t object, vm_page_t *m, int count,
1161     int flags, int *rtvals)
1162 {
1163         int rtval;
1164         struct vnode *vp;
1165         int bytes = count * PAGE_SIZE;
1166
1167         /*
1168          * Force synchronous operation if we are extremely low on memory
1169          * to prevent a low-memory deadlock.  VOP operations often need to
1170          * allocate more memory to initiate the I/O ( i.e. do a BMAP
1171          * operation ).  The swapper handles the case by limiting the amount
1172          * of asynchronous I/O, but that sort of solution doesn't scale well
1173          * for the vnode pager without a lot of work.
1174          *
1175          * Also, the backing vnode's iodone routine may not wake the pageout
1176          * daemon up.  This should be probably be addressed XXX.
1177          */
1178
1179         if (vm_page_count_min())
1180                 flags |= VM_PAGER_PUT_SYNC;
1181
1182         /*
1183          * Call device-specific putpages function
1184          */
1185         vp = object->handle;
1186         VM_OBJECT_WUNLOCK(object);
1187         rtval = VOP_PUTPAGES(vp, m, bytes, flags, rtvals);
1188         KASSERT(rtval != EOPNOTSUPP,
1189             ("vnode_pager: stale FS putpages\n"));
1190         VM_OBJECT_WLOCK(object);
1191 }
1192
1193 static int
1194 vn_off2bidx(vm_ooffset_t offset)
1195 {
1196
1197         return ((offset & PAGE_MASK) / DEV_BSIZE);
1198 }
1199
1200 static bool
1201 vn_dirty_blk(vm_page_t m, vm_ooffset_t offset)
1202 {
1203
1204         KASSERT(IDX_TO_OFF(m->pindex) <= offset &&
1205             offset < IDX_TO_OFF(m->pindex + 1),
1206             ("page %p pidx %ju offset %ju", m, (uintmax_t)m->pindex,
1207             (uintmax_t)offset));
1208         return ((m->dirty & ((vm_page_bits_t)1 << vn_off2bidx(offset))) != 0);
1209 }
1210
1211 /*
1212  * This is now called from local media FS's to operate against their
1213  * own vnodes if they fail to implement VOP_PUTPAGES.
1214  *
1215  * This is typically called indirectly via the pageout daemon and
1216  * clustering has already typically occurred, so in general we ask the
1217  * underlying filesystem to write the data out asynchronously rather
1218  * then delayed.
1219  */
1220 int
1221 vnode_pager_generic_putpages(struct vnode *vp, vm_page_t *ma, int bytecount,
1222     int flags, int *rtvals)
1223 {
1224         vm_object_t object;
1225         vm_page_t m;
1226         vm_ooffset_t maxblksz, next_offset, poffset, prev_offset;
1227         struct uio auio;
1228         struct iovec aiov;
1229         off_t prev_resid, wrsz;
1230         int count, error, i, maxsize, ncount, pgoff, ppscheck;
1231         bool in_hole;
1232         static struct timeval lastfail;
1233         static int curfail;
1234
1235         object = vp->v_object;
1236         count = bytecount / PAGE_SIZE;
1237
1238         for (i = 0; i < count; i++)
1239                 rtvals[i] = VM_PAGER_ERROR;
1240
1241         if ((int64_t)ma[0]->pindex < 0) {
1242                 printf("vnode_pager_generic_putpages: "
1243                     "attempt to write meta-data 0x%jx(%lx)\n",
1244                     (uintmax_t)ma[0]->pindex, (u_long)ma[0]->dirty);
1245                 rtvals[0] = VM_PAGER_BAD;
1246                 return (VM_PAGER_BAD);
1247         }
1248
1249         maxsize = count * PAGE_SIZE;
1250         ncount = count;
1251
1252         poffset = IDX_TO_OFF(ma[0]->pindex);
1253
1254         /*
1255          * If the page-aligned write is larger then the actual file we
1256          * have to invalidate pages occurring beyond the file EOF.  However,
1257          * there is an edge case where a file may not be page-aligned where
1258          * the last page is partially invalid.  In this case the filesystem
1259          * may not properly clear the dirty bits for the entire page (which
1260          * could be VM_PAGE_BITS_ALL due to the page having been mmap()d).
1261          * With the page locked we are free to fix-up the dirty bits here.
1262          *
1263          * We do not under any circumstances truncate the valid bits, as
1264          * this will screw up bogus page replacement.
1265          */
1266         VM_OBJECT_RLOCK(object);
1267         if (maxsize + poffset > object->un_pager.vnp.vnp_size) {
1268                 if (!VM_OBJECT_TRYUPGRADE(object)) {
1269                         VM_OBJECT_RUNLOCK(object);
1270                         VM_OBJECT_WLOCK(object);
1271                         if (maxsize + poffset <= object->un_pager.vnp.vnp_size)
1272                                 goto downgrade;
1273                 }
1274                 if (object->un_pager.vnp.vnp_size > poffset) {
1275                         maxsize = object->un_pager.vnp.vnp_size - poffset;
1276                         ncount = btoc(maxsize);
1277                         if ((pgoff = (int)maxsize & PAGE_MASK) != 0) {
1278                                 pgoff = roundup2(pgoff, DEV_BSIZE);
1279
1280                                 /*
1281                                  * If the object is locked and the following
1282                                  * conditions hold, then the page's dirty
1283                                  * field cannot be concurrently changed by a
1284                                  * pmap operation.
1285                                  */
1286                                 m = ma[ncount - 1];
1287                                 vm_page_assert_sbusied(m);
1288                                 KASSERT(!pmap_page_is_write_mapped(m),
1289                 ("vnode_pager_generic_putpages: page %p is not read-only", m));
1290                                 MPASS(m->dirty != 0);
1291                                 vm_page_clear_dirty(m, pgoff, PAGE_SIZE -
1292                                     pgoff);
1293                         }
1294                 } else {
1295                         maxsize = 0;
1296                         ncount = 0;
1297                 }
1298                 for (i = ncount; i < count; i++)
1299                         rtvals[i] = VM_PAGER_BAD;
1300 downgrade:
1301                 VM_OBJECT_LOCK_DOWNGRADE(object);
1302         }
1303
1304         auio.uio_iov = &aiov;
1305         auio.uio_segflg = UIO_NOCOPY;
1306         auio.uio_rw = UIO_WRITE;
1307         auio.uio_td = NULL;
1308         maxblksz = roundup2(poffset + maxsize, DEV_BSIZE);
1309
1310         for (prev_offset = poffset; prev_offset < maxblksz;) {
1311                 /* Skip clean blocks. */
1312                 for (in_hole = true; in_hole && prev_offset < maxblksz;) {
1313                         m = ma[OFF_TO_IDX(prev_offset - poffset)];
1314                         for (i = vn_off2bidx(prev_offset);
1315                             i < sizeof(vm_page_bits_t) * NBBY &&
1316                             prev_offset < maxblksz; i++) {
1317                                 if (vn_dirty_blk(m, prev_offset)) {
1318                                         in_hole = false;
1319                                         break;
1320                                 }
1321                                 prev_offset += DEV_BSIZE;
1322                         }
1323                 }
1324                 if (in_hole)
1325                         goto write_done;
1326
1327                 /* Find longest run of dirty blocks. */
1328                 for (next_offset = prev_offset; next_offset < maxblksz;) {
1329                         m = ma[OFF_TO_IDX(next_offset - poffset)];
1330                         for (i = vn_off2bidx(next_offset);
1331                             i < sizeof(vm_page_bits_t) * NBBY &&
1332                             next_offset < maxblksz; i++) {
1333                                 if (!vn_dirty_blk(m, next_offset))
1334                                         goto start_write;
1335                                 next_offset += DEV_BSIZE;
1336                         }
1337                 }
1338 start_write:
1339                 if (next_offset > poffset + maxsize)
1340                         next_offset = poffset + maxsize;
1341
1342                 /*
1343                  * Getting here requires finding a dirty block in the
1344                  * 'skip clean blocks' loop.
1345                  */
1346                 MPASS(prev_offset < next_offset);
1347
1348                 VM_OBJECT_RUNLOCK(object);
1349                 aiov.iov_base = NULL;
1350                 auio.uio_iovcnt = 1;
1351                 auio.uio_offset = prev_offset;
1352                 prev_resid = auio.uio_resid = aiov.iov_len = next_offset -
1353                     prev_offset;
1354                 error = VOP_WRITE(vp, &auio,
1355                     vnode_pager_putpages_ioflags(flags), curthread->td_ucred);
1356
1357                 wrsz = prev_resid - auio.uio_resid;
1358                 if (wrsz == 0) {
1359                         if (ppsratecheck(&lastfail, &curfail, 1) != 0) {
1360                                 vn_printf(vp, "vnode_pager_putpages: "
1361                                     "zero-length write at %ju resid %zd\n",
1362                                     auio.uio_offset, auio.uio_resid);
1363                         }
1364                         VM_OBJECT_RLOCK(object);
1365                         break;
1366                 }
1367
1368                 /* Adjust the starting offset for next iteration. */
1369                 prev_offset += wrsz;
1370                 MPASS(auio.uio_offset == prev_offset);
1371
1372                 ppscheck = 0;
1373                 if (error != 0 && (ppscheck = ppsratecheck(&lastfail,
1374                     &curfail, 1)) != 0)
1375                         vn_printf(vp, "vnode_pager_putpages: I/O error %d\n",
1376                             error);
1377                 if (auio.uio_resid != 0 && (ppscheck != 0 ||
1378                     ppsratecheck(&lastfail, &curfail, 1) != 0))
1379                         vn_printf(vp, "vnode_pager_putpages: residual I/O %zd "
1380                             "at %ju\n", auio.uio_resid,
1381                             (uintmax_t)ma[0]->pindex);
1382                 VM_OBJECT_RLOCK(object);
1383                 if (error != 0 || auio.uio_resid != 0)
1384                         break;
1385         }
1386 write_done:
1387         /* Mark completely processed pages. */
1388         for (i = 0; i < OFF_TO_IDX(prev_offset - poffset); i++)
1389                 rtvals[i] = VM_PAGER_OK;
1390         /* Mark partial EOF page. */
1391         if (prev_offset == poffset + maxsize && (prev_offset & PAGE_MASK) != 0)
1392                 rtvals[i++] = VM_PAGER_OK;
1393         /* Unwritten pages in range, free bonus if the page is clean. */
1394         for (; i < ncount; i++)
1395                 rtvals[i] = ma[i]->dirty == 0 ? VM_PAGER_OK : VM_PAGER_ERROR;
1396         VM_OBJECT_RUNLOCK(object);
1397         VM_CNT_ADD(v_vnodepgsout, i);
1398         VM_CNT_INC(v_vnodeout);
1399         return (rtvals[0]);
1400 }
1401
1402 int
1403 vnode_pager_putpages_ioflags(int pager_flags)
1404 {
1405         int ioflags;
1406
1407         /*
1408          * Pageouts are already clustered, use IO_ASYNC to force a
1409          * bawrite() rather then a bdwrite() to prevent paging I/O
1410          * from saturating the buffer cache.  Dummy-up the sequential
1411          * heuristic to cause large ranges to cluster.  If neither
1412          * IO_SYNC or IO_ASYNC is set, the system decides how to
1413          * cluster.
1414          */
1415         ioflags = IO_VMIO;
1416         if ((pager_flags & (VM_PAGER_PUT_SYNC | VM_PAGER_PUT_INVAL)) != 0)
1417                 ioflags |= IO_SYNC;
1418         else if ((pager_flags & VM_PAGER_CLUSTER_OK) == 0)
1419                 ioflags |= IO_ASYNC;
1420         ioflags |= (pager_flags & VM_PAGER_PUT_INVAL) != 0 ? IO_INVAL: 0;
1421         ioflags |= (pager_flags & VM_PAGER_PUT_NOREUSE) != 0 ? IO_NOREUSE : 0;
1422         ioflags |= IO_SEQMAX << IO_SEQSHIFT;
1423         return (ioflags);
1424 }
1425
1426 /*
1427  * vnode_pager_undirty_pages().
1428  *
1429  * A helper to mark pages as clean after pageout that was possibly
1430  * done with a short write.  The lpos argument specifies the page run
1431  * length in bytes, and the written argument specifies how many bytes
1432  * were actually written.  eof is the offset past the last valid byte
1433  * in the vnode using the absolute file position of the first byte in
1434  * the run as the base from which it is computed.
1435  */
1436 void
1437 vnode_pager_undirty_pages(vm_page_t *ma, int *rtvals, int written, off_t eof,
1438     int lpos)
1439 {
1440         vm_object_t obj;
1441         int i, pos, pos_devb;
1442
1443         if (written == 0 && eof >= lpos)
1444                 return;
1445         obj = ma[0]->object;
1446         VM_OBJECT_WLOCK(obj);
1447         for (i = 0, pos = 0; pos < written; i++, pos += PAGE_SIZE) {
1448                 if (pos < trunc_page(written)) {
1449                         rtvals[i] = VM_PAGER_OK;
1450                         vm_page_undirty(ma[i]);
1451                 } else {
1452                         /* Partially written page. */
1453                         rtvals[i] = VM_PAGER_AGAIN;
1454                         vm_page_clear_dirty(ma[i], 0, written & PAGE_MASK);
1455                 }
1456         }
1457         if (eof >= lpos) /* avoid truncation */
1458                 goto done;
1459         for (pos = eof, i = OFF_TO_IDX(trunc_page(pos)); pos < lpos; i++) {
1460                 if (pos != trunc_page(pos)) {
1461                         /*
1462                          * The page contains the last valid byte in
1463                          * the vnode, mark the rest of the page as
1464                          * clean, potentially making the whole page
1465                          * clean.
1466                          */
1467                         pos_devb = roundup2(pos & PAGE_MASK, DEV_BSIZE);
1468                         vm_page_clear_dirty(ma[i], pos_devb, PAGE_SIZE -
1469                             pos_devb);
1470
1471                         /*
1472                          * If the page was cleaned, report the pageout
1473                          * on it as successful.  msync() no longer
1474                          * needs to write out the page, endlessly
1475                          * creating write requests and dirty buffers.
1476                          */
1477                         if (ma[i]->dirty == 0)
1478                                 rtvals[i] = VM_PAGER_OK;
1479
1480                         pos = round_page(pos);
1481                 } else {
1482                         /* vm_pageout_flush() clears dirty */
1483                         rtvals[i] = VM_PAGER_BAD;
1484                         pos += PAGE_SIZE;
1485                 }
1486         }
1487 done:
1488         VM_OBJECT_WUNLOCK(obj);
1489 }
1490
1491 void
1492 vnode_pager_update_writecount(vm_object_t object, vm_offset_t start,
1493     vm_offset_t end)
1494 {
1495         struct vnode *vp;
1496         vm_ooffset_t old_wm;
1497
1498         VM_OBJECT_WLOCK(object);
1499         if (object->type != OBJT_VNODE) {
1500                 VM_OBJECT_WUNLOCK(object);
1501                 return;
1502         }
1503         old_wm = object->un_pager.vnp.writemappings;
1504         object->un_pager.vnp.writemappings += (vm_ooffset_t)end - start;
1505         vp = object->handle;
1506         if (old_wm == 0 && object->un_pager.vnp.writemappings != 0) {
1507                 ASSERT_VOP_ELOCKED(vp, "v_writecount inc");
1508                 VOP_ADD_WRITECOUNT(vp, 1);
1509                 CTR3(KTR_VFS, "%s: vp %p v_writecount increased to %d",
1510                     __func__, vp, vp->v_writecount);
1511         } else if (old_wm != 0 && object->un_pager.vnp.writemappings == 0) {
1512                 ASSERT_VOP_ELOCKED(vp, "v_writecount dec");
1513                 VOP_ADD_WRITECOUNT(vp, -1);
1514                 CTR3(KTR_VFS, "%s: vp %p v_writecount decreased to %d",
1515                     __func__, vp, vp->v_writecount);
1516         }
1517         VM_OBJECT_WUNLOCK(object);
1518 }
1519
1520 void
1521 vnode_pager_release_writecount(vm_object_t object, vm_offset_t start,
1522     vm_offset_t end)
1523 {
1524         struct vnode *vp;
1525         struct mount *mp;
1526         vm_offset_t inc;
1527
1528         VM_OBJECT_WLOCK(object);
1529
1530         /*
1531          * First, recheck the object type to account for the race when
1532          * the vnode is reclaimed.
1533          */
1534         if (object->type != OBJT_VNODE) {
1535                 VM_OBJECT_WUNLOCK(object);
1536                 return;
1537         }
1538
1539         /*
1540          * Optimize for the case when writemappings is not going to
1541          * zero.
1542          */
1543         inc = end - start;
1544         if (object->un_pager.vnp.writemappings != inc) {
1545                 object->un_pager.vnp.writemappings -= inc;
1546                 VM_OBJECT_WUNLOCK(object);
1547                 return;
1548         }
1549
1550         vp = object->handle;
1551         vhold(vp);
1552         VM_OBJECT_WUNLOCK(object);
1553         mp = NULL;
1554         vn_start_write(vp, &mp, V_WAIT);
1555         vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
1556
1557         /*
1558          * Decrement the object's writemappings, by swapping the start
1559          * and end arguments for vnode_pager_update_writecount().  If
1560          * there was not a race with vnode reclaimation, then the
1561          * vnode's v_writecount is decremented.
1562          */
1563         vnode_pager_update_writecount(object, end, start);
1564         VOP_UNLOCK(vp, 0);
1565         vdrop(vp);
1566         if (mp != NULL)
1567                 vn_finished_write(mp);
1568 }